bluuebunny/crossref_metadata_2025 huggingface dataset:
Intraoral distribution of Actinobacillus actinomycetemcomitans in young adults with minimal periodontal disease
Authors: Müller H.‐P. , Heinecke A. , Fuhrmann A. , Eger T. , Zöller L.
Published: March 2003

The aim of the present study was to investigate the intraoral distribution of Actinobacillus actinomycetemcomitans in young adults with minor signs of periodontal disease but harboring the organisms in the oral cavity. 17 healthy volunteers, 20 to 27 years of age, participated. Samples from mucosal surfaces of the oro‐pharyngeal cavity and saliva (n=221) as well as subgingival plaque from every tooth (n=477) were selectively cultivated for A. actinomycetemcomitans. Species identity and presence of the leukotoxin encoding gene, ltxA, were checked by multiplex polymerase chain reaction. Moreover, the leukotoxin promoter region was analyzed. No isolate harbored a 530 bp deletion in the promoter region of the leukotoxin gene, signaling minimally toxic strains. 42.1±30.4% extracrevicular and 34.4±29.5% subgingival samples were culture‐positive. In extracrevicular samples, the organism could easily be recovered from cheek mucosa (62%), saliva (59%) and the palatal tonsils (41%). Mean log‐transformed numbers of A. actinomycetemcomitans colony forming units (CFU/ml) in culture‐positive material ranged between 1.8 from the hard palate and 2.3 from 10 μl saliva. The highest prevalence in subgingival plaque was observed at maxillary 3rd molars (55%) followed by maxillary lateral incisors (50%) and mandibular 3rd molars (41%). Mean log‐transformed counts of CFU/ml ranged between 2.2 at maxillary 3rd molars and 3.4 at upper central incisors. When adjusted for jaw, site and tooth type, the odds of isolating higher numbers of the organism were increased with every mm probing depth by a factor of 1.35 (p<0.05). The odds ratio for bleeding on probing was 1.38. Thus, in this young adult population with minor periodontal disease, A. actinomycetemcomitans was mainly associated with some deviation from gingival health. Of concern might be a minority of subjects (29%) with an extremely wide distribution of the organism in the oral cavity.
Histometric evaluation of the effect of nicotine administration on periodontal breakdown: an in vivo study
Authors: Nociti Francisco H. , Nogueira‐Filho Getúlio R. , Tramontina Vinícius A. , Naval Machado Maria A. , Barros Silvana P. , Sallum Enilson A. , Sallum Antonio Wilson
Published: March 2003

The present study investigated the effect of nicotine administration on periodontal breakdown resulting from ligature‐induced periodontitis in rats. Twenty adult male Wistar rats were used. After anesthesia, a mandibular first molar was randomly assigned to receive a cotton ligature in the sulcular area while the contralateral tooth was left unligated. The animals were randomly assigned to one of the following treatments, of daily intraperitoneal injections: A – saline solution, B – 0.37 mg of nicotine/kg, C – 0.57 mg of nicotine/kg and D – 0.73 mg of nicotine/kg. Thirty days later, the animals were sacrificed and the specimens routinely processed for serial decalcified sections. Statistical analysis (ANOVA) revealed greater bone loss (p<0.05) in the ligated teeth of animals which received nicotine (groups B/C/D) than in the ligated teeth of animals which received saline solution (group A). In addition, a dose‐dependent response was observed among the nicotine groups. A negative effect of nicotine was observed in the unligated teeth of the experimental groups (p<0.05). Therefore, daily administration of nicotine enhanced, in a dose‐dependent manner, the effects of local factors in producing periodontal breakdown. Furthermore, the nicotine seemed to have a direct deleterious effect on the periodontal tissues.
Recognition of the carbohydrate modifications to the RgpA protease of Porphyromonas gingivalis by periodontal patient serum IgG
Authors: Slaney Jennifer M. , Rangarajan Minnie , Aduse‐Opoku Joseph , Fawell Stuart , Darby Ivan , Kinane Denis , Curtis Michael A.
Published: March 2003

Periodontal infections by Porphyromonas gingivalis are associated with a sustained systemic IgG antibody response and elevations in local antibody synthesis to this organism. One of the targets of this response is a protease, RgpAcat, which is an important virulence determinant of this organism. Recently, we demonstrated that this molecule is glycosylated and that the glycan chains are immunologically related to P. gingivalis lipopolysaccharide (LPS) (Curtis et al., Infect Immun 1999;62:3816–3823). In the present study, we examined the role of these glycan additions in the immune recognition of RgpAcat by sera from adult periodontal patients (n = 25). Serum IgG antibody levels to P. gingivalis W50, RgpAcat and LPS and to recombinant RgpA were determined by enzyme‐linked immunosorbant assay (ELISA). No correlation was observed between the antibody levels to RgpAcat from P. gingivalis and the recombinant form of this enzyme expressed in Escherichia coli. However, a strong association was found between the recognition of LPS and the wild‐type enzyme (R = 0.8926; p = 0.0005). Incorporation of LPS into the ELISA led to a significant reduction (mean 25%; range 0.8–43%, SD = 15; p < 0.05) in the recognition of RgpAcat, but had no effect on the recognition of control antigens. Deglycosylation of RgpAcat led to the abolition of immune recognition by patient serum IgG, which suggests that the glycan additions to this molecule are the principal targets of the immune response. Therefore, glycosylation of the RgpAcat protease may play an important role in immune evasion by shielding the primary structure from immune recognition.
Upregulation of co‐stimulatory molecule expression and dendritic cell marker (CD83) on B cells in periodontal disease
Authors: Mahanonda Rangsini , Sa‐Ard‐Iam Noppadol , Yongvanitchit Kosol , Wisetchang Mahisorn , Ishikawa Isao , Nagasawa Toshiyuki , Walsh Douglas S. , Pichyangkul Sathit
Published: March 2003

T cells and their cytokines are well known for their important role in the pathogenesis of periodontitis. To date, the role of antigen presenting cells (APCs), which are known to be critical in the regulation of T cell response, has been poorly investigated in periodontitis. In this study, we analyzed the expression of co‐stimulatory molecules (CD80 and CD86) and CD83, which is a marker of mature dendritic cells, on gingival cells that were isolated from severe periodontitis tissues, with the use of flow cytometry. Significant upregulation of CD86 and CD83 expression was detected in periodontitis lesions, and most of this occurred on B cells. In vitro peripheral blood mononuclear cell cultures showed that stimulation with different periodontopathic bacteria, that included Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, Prevotella intermedia, and Actinomyces viscosus, upregulated both CD86 and CD83 expression on B cells. Therefore, the presence of plaque bacteria may be responsible for the enhanced expression seen in vivo on gingival B cells. APC function by bacterial‐activated B cells was further investigated using allogeneic mixed leukocyte reactions. After 24 h culture with either A. actinomycetemcomitans or P. gingivalis, these activated B cells performed as potent APCs in mixed leukocyte reactions, and they stimulated T cells to produce high levels of gamma interferon and minimal interleukin‐5. In conclusion, periodontopathic bacterial‐induced B cell activation with upregulation of CD86 and CD83 may be associated with enhanced APC function. The results of this study suggest, therefore, that infiltrated gingival B cells have a possible role as APCs in the regulation and maintenance of local T cell response in periodontitis.
Relationship between vitamin D receptor gene polymorphism and periodontitis
Authors: Sun J. L. , Meng H. X. , Cao C. F. , Tachi Y. , Shinohara M. , Ueda M. , Imai H. , Ohura K.
Published: March 2003

Recent studies have shown that vitamin D receptor (VDR) gene polymorphism had regulatory effects on bone mineral density (BMD) and bone turnover. The VDR gene has also been indicated as a candidate gene for the susceptibility of osteoporosis. However, it is unclear whether VDR genotypes could be associated with alveolar bone loss of patients with periodontitis, or whether vitamin D receptor gene could be a candidate gene for susceptibility to periodontitis. The purpose of this study was to answer these two questions.

Methods:
Twenty‐four cases of adult periodontitis (AP), 37 cases of early onset periodontitis (EOP) and 39 healthy controls were recruited for the study. Individual samples of venous blood and DNA were obtained from each subject. Genotypes of the TaqI VDR gene were determined by PCR and TaqI restriction endonuclease digestion.

Results:
One out of 24 AP patients, nine out of 37 EOP patients and two out of 39 healthy controls were detected with Tt genotype, while the rest had the TT genotype. The detected frequency of Tt genotype was significantly higher in EOP patients (24.3%) than in AP patients (4.2%) and healthy controls (5.1%). The frequency of t allele was also significantly higher in EOP patients. There was no statistical difference in the distribution of TaqI VDR genotypes between AP patients and healthy controls. The study suggests that Tt genotype might be a risk indicator for the susceptibility to EOP. Carriage of the allele (t) of the TaqI VDR gene may increase the risk of developing EOP.
Three case reports of aggressive periodontitis associated with Porphyromonas gingivalis in younger patients
Authors: Ishikawa Isao , Kawashima Yoko , Oda Shigeru , Iwata Takanori , Arakawa Shinichi
Published: March 2003

The terms ‘early onset periodontitis’ (EOP) and ‘juvenile periodontitis’ (JP) were replaced by that of ‘aggressive periodontitis’ in a recent international workshop for the classification of periodontal diseases and conditions. The chief etiologic agent for aggressive periodontitis is considered to be Actinobacillus actinomycetemcomitans in localized juvenile periodontitis. Porphyromonas gingivalis is also mentioned as the etiologic agent of the aggressive periodontitis, although to date its role remains questionable. This communication describes three cases of aggressive periodontitis found to be associated with P. gingivalis but not A. actinomycetemcomitans by polymerase chain reaction (PCR) and enzyme‐linked immunosorbent assay (ELISA). Our findings clarify the role of P. gingivalis as an etiologic agent in this type of periodontitis and confirm its inclusion in the current definition of aggressive periodontitis.
Identification of a new variant of fimA gene of Porphyromonas gingivalis and its distribution in adults and disabled populations with periodontitis
Authors: Nakagawa I. , Amano A. , Ohara‐Nemoto Y. , Endoh N. , Morisaki I. , Kimura S. , Kawabata S. , Hamada S.
Published: March 2003

Porphyromonas gingivalis fimbriae are critical for the promotion of bacterial infection. The fimA gene encoding fimbrillin, a subunit of fimbriae, has been classified into five genotypes (types I to V) based on their nucleotide sequences. Using a fimA type‐specific PCR assay, our previous study demonstrated a close relationship between P. gingivalis possessing type II and type IV fimA genes and adult periodontitis. In that study, some clinical specimens were found to be positive for both types I‐ and II‐ fimA specific primers, likely due to the coexistence of two clonal types or a single clone of an unknown genotype in the samples. In the present study, we cloned a new variant of the fimA gene, designated as type Ib fimA, from P. gingivalis HG1691. The nucleotide sequence of the cloned fimA gene showed a 97.1% homology with that of type I fimA, indicating it as a clonal variant of type I fimA. Organisms with type Ib fimA were detected in 13.5% of periodontitis patients and in 2.9% of periodontal healthy adults. Statistical analysis revealed a strong relationship between periodontitis and specific fimA types such as type Ib [odds ratio (OR) 6.51], type II (OR 77.8), and type IV (OR 7.54). Moreover, type Ib fimA‐organisms were also found to be related to periodontitis in Down's syndrome (OR 1.91) and mentally disabled populations (OR 4.00). These findings suggest that P. gingivalis with type Ib fimA is closely associated with the progression of periodontitis, similar to organisms with type II and IV fimA.
Activation of MMP‐2 by Porphyromonas gingivalis in human periodontal ligament cells
Authors: Pattamapun Kassara , Tiranathanagul Siriluck , Yongchaitrakul Tussanee , Kuwatanasuchat Jintakorn , Pavasant Prasit
Published: March 2003

It has been reported that matrix metalloproteinase (MMP) produced by host cells plays a major role in periodontal tissue destruction. In addition, secreted virulence factors from Porphyromonas gingivalis can alter MMP secretion and cause activation in host cells that lead to the tissue degradation. In this study, we examine the effects of P. gingivalis supernatant on matrix metalloproteinase‐2 (MMP‐2) activation in human periodontal ligament (HPDL) cells. Cultures of HPDL cells were treated with P. gingivalis supernatant for 48 h and the level of MMP‐2 activation was monitored by gelatin zymography. The profound activation of MMP‐2 was seen only in the treated group. The activation of MMP‐2 was inhibited by MMP inhibitors phenanthroline and EDTA, but not serine protease or cysteine protease inhibitors. To study the correlation between the expression of membrane‐type‐1 matrix metalloproteinase (MT1‐MMP) and the activation of MMP‐2, the level of MT1‐MMP was analyzed. The results from reverse‐transcription polymerase chain reaction (RT‐PCR) and Western analysis indicated that P. gingivalis supernatant up‐regulated the expression of MT1‐MMP in both transcription and translation levels within 48 h. These results suggest that P. gingivalis supernatant can activate MMP‐2 in HPDL cells and the mechanism of activation may involve the increased amount of MT1‐MMP. It is possible that the activation of MMP‐2 by P. gingivalis plays a role in the process of chronic periodontitis.
The Mechanism Underlying the Protective Effect of the Thearubigin Fraction of Black Tea (Camellia sinensis) Extract against the Neuromuscular Blocking Action of Botulinum Neurotoxins
Authors: Satoh Eiki , Ishii Toshiaki , Shimizu Yoshio , Sawamura Shin‐ichi , Nishimura Masakazu
Published: March 2003

Abstract: The aim of the present study was to elucidate the mechanism of the protective effect of black tea extract, the thearubigin fraction, against the neuromuscular blocking action of botulinum neurotoxin types A, B, and E. The effects of thearubigin fraction extracted from a black tea infusion were examined on the neuromuscular blocking action of botulinum neurotoxin types A, B, and E in mouse phrenic nerve‐diaphragm preparations and on the binding of these toxins to rat cerebrocortical synaptosomes. Botulinum neurotoxin type A (1.5 nM), B (6 nM), or E (5 nM) abolished indirect twitches in mouse phrenic nerve‐diaphragm preparations within 50, 90, 90 min., respectively. Thearubigin fraction mixed with each toxin blocked the inhibitory effect of the toxins. The specific binding of [125I]botulinum neurotoxin type A, B, or E to rat cerebrocortical synaptosomes was inhibited by mixing iodinated toxin with thearubigin fraction. The elution profile of [125I]botulinum neurotoxin type A, B, or E on Sephadex G‐50 column chromatography was different from that of toxin mixed with thearubigin fraction. These findings indicate that thearubigin fraction protects against the neuromuscular blocking action of botulinum neurotoxin types A, B, and E by binding with the toxins.
Reduction in 8‐methoxypsoralen immersion time alters the erythemal response to bath PUVA
Authors: Azurdia R. M. , Dean M. P. , Rhodes L. E.
Published: March 2003

Topical psoralen plus ultraviolet A (PUVA) using 8‐methoxypsoralen (8‐MOP) bath solution is a well established and effective treatment in dermatology. The standard immersion time in the UK is 15 min, but a shorter bathing period could potentially increase treatment convenience. In order to examine the effect of reduction in immersion time on skin phototoxicity, we compared the erythemal response to UVA following 5 min and 15 min psoralen baths. The study was performed on the forearm skin of 7 healthy volunteers using an 8‐MOP psoralen concentration of 2.6 mg/l. One forearm of each volunteer was soaked for 15 min and the other for 5 min, followed by immediate irradiation with a series of 10 doses of broadband UVA ranging from 0.1 J/cm2 to 6.9 J/cm2. At 72 h, the minimal phototoxic doses (MPDs) were noted and erythema readings (erythema index) were taken in triplicate with a reflectance instrument. The median MPD following 5 min immersion was 1.7 (range 0.7–2.7) J/cm2 compared with 1.0 (range 0.4–1.7) J/cm2 after 15 min treatment, with no significant difference. However, the mean slope of erythema dose–response on the 15‐min treated side was significantly steeper than on the 5‐min treated side, 0.036 and 0.021 respectively, P< 0.05. Hence, this preliminary work shows that reducing 8‐MOP immersion time to 5 min reduces the erythemal response to UVA. It will clearly be necessary to examine the effect of a shortened immersion period on disease clearance before considering such a change to the topical PUVA regime.
Subliminal ultraviolet‐B irradiation for the prevention of vitamin D deficiency in the elderly: a feasibility study
Authors: Chuck Alexis , Todd Joanne , Diffey Brian
Published: March 2003

Aim:

To investigate whether daily subliminal ultraviolet‐B irradiation in elderly subjects can maintain a normal vitamin D status.

Material and methods:

In an open, uncontrolled study, 10 residents (four men and six women), mean age on entry of 83 years (range 65–97 years), from a residential nursing home in County Durham, England, were exposed daily to an artificial source of ultraviolet‐B radiation equivalent to 15 min of summer sunshine. The change in plasma 25‐hydroxyvitamin D levels following irradiation was measured.

Results: Improvement in the vitamin D status of the elderly residents was achieved with no change in their routine and with no intervention on the part of carers.

Conclusions: On the basis of this small pilot study we conclude that subliminal ultraviolet‐B irradiation may be effective in maintaining vitamin D status in elderly people at a lower cost than that of using oral vitamin D supplementation. Further controlled studies are needed before this technique can be recommended to change health policy with regard to the vitamin D status of institutionalised elderly people.
013 Effect of UV on the susceptibility of acid‐soluble Skh‐1 hairless mouse collagen to collagenase
Authors: Menter J.M. , Cornelison L.M. , Patta A.M. , Sayer R.M. , Abukhalaf I.K. , Silvestrov N.S. , Willis I.
Published: March 2003

To test the hypothesis that UV could alter collagen susceptibility to interstitial collagenase, acid‐extracted Skh‐1 hairless mouse collagen samples were (un)irradiated with 0–140 J/cm2 of radiation from bank of filtered FS lamp (UVB/UVA = 0.33, fluence rate = 0.81 mW/cm2). Subsequent to UV irradiation, collagen samples were coupled with fluorescein isothiocyanate (FITC) and assayed for its susceptibility to bacterial collagenase by monitoring the appearance of supernatant FITC fluorescence (a measure of lysed collagen) over time of incubation. As a reference. unirradiated commercial FITC – labeled collagen (Elastin Products) was similarly analyzed. Mouse collagen had a lower rate of cleavage than did the calf skin sample. Mouse collagen initial cleavage followed a quasi‐linear time course over the first 5 h. Calf‐skin collagen displayed a ‘sigmoidal’ time course, reminiscent of a cooperative mechanism. UV irradiation afforded no significant effect on the ability of collagenase to cleave mouse collagen, although a small effect could be discerned after 48 h (140 J/cm2). On the other hand, these samples exhibited significant chain degradation. cross‐linking and loss of intrinsic collagen fluorescence on UV photolysis. It appears that the rate of cleavage depends on the superstructure of the collagen, and that the collagen fluorophores are not in proximity to the specific site of collagenase cleavage.

Supported in part by NIH/MBRS Grant #GM 08248 and RCMI Grant #RR 03034.
018 New source for evaluating PDT drugs in the laboratory
Authors: Sayre R.M. , Dowdy J.C. , Gart M.
Published: March 2003

Laboratory comparison of different PDT drugs can pose a number of problems because of sources with different exposure geometries and excitation wavebands. This can be overcome by utilizing a single source consisting of a quartz halogen source filtered with appropriate narrow band pass, interference type filters. The source is modified to provide eight simultaneous exposures to samples in 96 well tissue culture plates. This enables a substantial number of exposures to be performed for comparative effectiveness studies. By simply changing optical band pass filters different drugs can be tested in the same plates or subsequent plates. By irradiating each plate from the bottom, all wells can be comparably exposed irrespective of media volume.
020 Adult onset erythropoietic protoporphyria in association with myelodysplastic syndrome
Authors: Thornton Spann C. , Tok J. , Nimmer S. , Zug K. , Deleo V.
Published: March 2003

Erythropoletic Protoporphyria (EPP) is normally a disease of childhood that has an autosomal dominant inheritance pattern. The mean age of onset is 4 years and it is characterized by variable photosensitivity caused by a defect in the ferrocheletase gene, resulting in accumulation of protoporphyrin in skin and erythroid tissues. A 60 year‐old male with no prior history or family history of EPP developed burning, pruritis, diffuse erythema and edema in sun‐exposed areas. He had a known historv of Myelodysplastic Syndrome (MDS), and his symptoms began several years after the MDS was diagnosed. Hematologic analysis revealed increased plasma and red blood cell protoporphyrins. Urinary porphyrins were normal. As these results are indicative of EPP, genetic analysis was performed to detect a mutation of the ferrocheletase gene. Genomic DNA was extracted from whole blood and amplified with primers flanking the exons of the ferrocheletase gene. The DNA was examined for mutations by direct sequencing, which revealed no sequence alteration in the ferrocheletase gene. It was therefore concluded that the patient's MDS led to dysplastic growth of stem cells and subsequent inhibition of blood ferrocheletase. The interruption of porphyrin metabolism by hematologic malignancies is exceedingly rare but well documented, and MDS has been linked to other types of porphyria in the past. However, there is only one other case in the literature of EPP as a sequelae of MDS. This is the only documented case of EPP caused by MDS that has the benefit of mutational analysis of the ferrocheletase gene.
022 308 excimer laser treatment of psoriasis
Authors: Taylor C.R. , Taneja A. , Gupta S. , Racette A. , Asawanonda P. , Trehan M.
Published: March 2003

The excimer 308 nm laser has recently been FDA‐approved in the United States for the treatment of psoriasis. Our center was the first to study this device systematically for this indication. Investigations to date have included an initial dose‐response study, a high‐dose as well as a medium‐dose one. Collectively, these results were analyzed and remission periods were reviewed. The rapidity of clearing as well as the severity of side‐effects showed a clear dose‐response relationship. Even thick plaques responded. The treatment process itself is quick and painless, allowing the operator to cover a palm‐sized area in just a minute. The laser is easy to use and there are no disfiguring purpura. By selectively focusing on lesional skin, overall cutaneous ultraviolet burden is minimized. Localized tanning is another side‐effect to be anticipated. Obviously, blistering doses show limited applicability as the sole treatment for extensive disease. Moreover, the long‐term risks associated with blistering directly on plaques of psoriasis themselves, while not clearly established, seem unlikely to be favorable. On the other hand, sub‐blistering doses appear to be extremely well‐tolerated. Wound care, except in the cases of blistering doses, is minimal. In short, the 308 nm excimer laser offers a novel targeted treatment modality for localized psoriasis, even when the plaques are quite thick.
Neuroprotection by melatonin from glutamate‐induced excitotoxicity during development of the cerebellum in the chick embryo
Authors: Espinar Auxiliadora , García‐Oliva Alejandro , Isorna Eva M. , Quesada Adela , Prada Francisco A. , Guerrero Juan M.
Published: March 2003

This work investigated the ability of melatonin to prevent cell damage in the cerebellar cortex of chick embryo caused by glutamate administration. Cell injury was evaluated estimating, at ultrastructural level, the phenomenon of cell death and the synaptogenesis of the Purkinje cells and the cerebellar glomerular synaptic complex. Administration of glutamate during cerebellar development of the chick provokes excitotoxic neuronal degeneration characterized by a phenomenon of neuronal cell death that exhibits essentially the features of a death pattern described as necrosis and the deletion of synaptogenic processes. Our results show that melatonin has a neuroprotective effect against glutamate‐induced excitotoxicity. This effect is morphologically revealed by the lack of neural cell death in the embryos treated with melatonin prior to glutamate injection and also by the degree of a synaptogenesis similar to that exhibited by the control group. Likewise, we corroborate the absence of teratological effects of melatonin on chick cerebellar development. Although the possible mechanisms involved in the neuroprotective effect of melatonin are discussed, i.e., direct antioxidant effects, up‐regulating endogenous antioxidant defenses, and inhibiting nitric oxide formation activated by glutamate, further studies are required to establish the actual mechanism involved in the neuroprotective effect of melatonin.
Identification and sequencing of pineal‐specific enhancing region in the mouse tryptophan hydroxylase promoter
Authors: Yim Sung‐Vin , Huh Sung‐Oh , Kim Jong‐Woo , Kim Mi‐Ja , Park Seung‐Joon , Jung Jee‐Chang , Chung Joo‐Ho
Published: March 2003

Pineal‐specific expression of the tryptophan hydroxylase (TPH) gene has been demonstrated by a number of studies. However, little is known about the regulatory mechanism for pineal‐specific expression of the TPH gene. To identify the cis‐acting region responsible for
pineal‐specific expression of the TPH gene, we investigated a 6.1‐kb
5′‐flanking region of the mouse TPH gene using an immortalized
pineal cell line (PGT‐β) derived from transgenic mice. By deletion
analysis, it was demonstrated that the pineal‐specific enhancing region
resides approximately between −6.1 and −4.7 kb upstream from
the transcription initiation site of the mouse TPH gene. Additionally,
nucleotide sequence analysis of this region showed that the
(AC/TG)22 repetitive sequence is located approximately
−5.78 kb upstream of the mouse TPH gene, and several known
tissue‐specific cis‐acting elements, such as Pit‐1 and the
pituitary specific element (PSE), have also been identified in the
region. We believe that the analysis of the sequence and several
cis‐acting elements in the pineal‐specific enhancing region of the mouse TPH promoter would enhance our understanding of the precise mechanism of pineal‐specific expression.
Role of extracellular calcium on the regulation of melatonin synthesis in the Syrian hamster pineal gland
Authors: Santana Celsa , Moujir Fatima , Sanchez JuanJose , Reiter Russel J. , Abreu Pedro
Published: March 2003

The role of extracellular calcium on the induction of cyclic AMP production, N‐acetyltransferase (NAT) activity and melatonin synthesis, induced by forskolin, was investigated in Syrian hamster pineal glands. Pineals were removed from hamsters killed either in the first half of the normal dark period or late in the dark period. Forskolin immediately increased NAT activity and melatonin levels only when the glands were collected late in the dark period, while in the first half of the dark phase, hamster pineals responded to forskolin with an increase of NAT activity and melatonin production only after 6 hr of incubation. The absence of calcium prevented the induction of melatonin synthesis by forskolin only when glands were collected early in the dark phase and incubated for 6 hr. In the second half of the normal dark period removal of calcium markedly decreased NAT activity and melatonin levels in glands incubated with forskolin for either 4 or 6 hr. However, the absence of extracellular calcium had no significant effect on the induction of cyclic AMP production by forskolin in pineals collected either early in the dark period or late in the dark phase. These data indicate that at least part of the action of extracellular calcium is indirect and that it affects steps in the induction of melatonin synthesis beyond the accumulation of cAMP.
Evaluation of plasma levels of melatonin after midazolam or sodium thiopental anesthesia in children
Authors: Muñoz‐Hoyos Antonio , Heredia Francisco , Moreno Francisco , García Joaquín José , Molina‐Carballo Antonio , Escames Germaine , Acuña‐Castroviejo Darío
Published: March 2003

Midazolam and sodium thiopental are two commonly used drugs in anesthesia for minor surgical procedures in children. A relationship exists between benzodiazepines (BNZ), barbiturates and melatonin. Whereas these drugs increase pineal melatonin production, the indoleamine amplifies the effects of both BNZ and barbiturates on the central nervous system (CNS). Our purpose was thus to analyze the plasma levels of melatonin before and during midazolam or sodium thiopental anesthesia in children subjected to ambulatory surgical procedures. Midazolam (0.4 mg/kg) or sodium thiopental (5 mg/kg) were administered i.v. to 33 and 32 children (aged between 2 and 14 yr), respectively, and blood samples were taken before and 5, 10 and 20 min after the drugs were administered. Melatonin was measured in plasma by a commercial radioimmunoassay kit previously standardized in our laboratory. The results showed that neither midazolam nor sodium thiopental anesthesia significantly affected the levels of melatonin studied at anytime. Significant correlations were found comparing the levels of melatonin between the different times studied. These results suggest that midazolam or sodium thiopental did not affect melatonin production by the pineal gland, thus avoiding a possible potentiating effect of the indoleamine on the central effects of these drugs during anesthesia. However, the possibility that changes in melatonin had been masked by the antioxidant role of the neurohormone are discussed.
Vascular reactivity in diabetic rats: effect of melatonin
Authors: Reyes‐Toso Carlos F. , Rosón María I. , Albornoz Liliana E. , Damiano Pablo F. , Linares Laura M. , Cardinali Daniel P.
Published: March 2003

The aim of the present study was to evaluate the in vitro contractile response of rat aorta in mild and severe type I diabetes and the effect of melatonin on it. Aortic rings were obtained from male Wistar rats injected with streptozotocin 8–12 wks earlier. Rats were divided into three groups: non‐diabetic rats (NDR), mildly diabetic rats (MDR) and severely diabetic rats (SDR). Dose–response curves for acetylcholine‐induced, endothelium‐related relaxation of aortic rings (after previous exposure to phenylephrine) and for serotonin‐induced vasoconstriction were conducted in the presence or absence of 10–5 mol/L melatonin. This protocol was repeated with rings preincubated in a high glucose solution (44 mmol/L). The contractile response to phenylephrine decreased in SDR, an effect counteracted by preincubation with high glucose. Melatonin decreased phenylephrine‐induced vasoconstriction in MDR and counteracted the effect of high glucose in SDR. Acetylcholine‐evoked relaxation decreased significantly after exposure to a high glucose in SDR, this effect being counteracted by melatonin. Serotonin‐induced vasoconstriction decreased in SDR and augmented in MDR, but only after exposure to high glucose. Melatonin reduced the maximal tension of aortic contraction after serotonin in MDR, both under basal conditions and after preincubation in a high glucose solution. The results support the existence of differences in vasomotor responses as a function of the diabetes state and of an improvement of contractile performance in diabetic rats after exposure to melatonin at a pharmacological concentration (in terms of circulating melatonin levels but not necessarily for some other fluids or tissues).
Cloning, localization and functional properties of a cGMP‐gated channel in photoreceptor cells from fish pineal gland
Authors: Decressac Sonia , Grechez‐Cassiau Aline , Lenfant Jacques , Falcón Jacky , Bois Patrick
Published: March 2003

Abstract: The perception of photic information and its translation into a rhythmic melatonin signal differ considerably among vertebrates. In the fish pineal gland, melatonin biosynthesis is controlled directly by the natural light/dark cycle. There are indications that the mechanisms of phototransduction are similar in the retinal and pineal photoreceptor cells. Here we report the molecular cloning of a novel ionic cyclic guanosine monophosphate (cGMP)‐gated channel from trout pineal photoreceptors. The deduced amino acid sequence exhibits a high sequence homology to cyclic nucleotide‐gated‐3 (CNG) channels from retinal cones. In situ hybridization with sections of trout pineal gland revealed the expression of CNG channel in photoreceptor cells of the pineal organ. Electrophysiological studies by means of patch‐clamp technique indicated that the native channel in photoreceptor cells and the expressed channel in a human cell line (HEK 293 cells) have properties similar to those of cone‐CNG (cCNG)‐3 channels. They are activated by cGMP, insensitive to cyclic adenosine monophosphate (cAMP) and blocked by intracellular Mg2+ ions at positive voltage values. They have a single‐channel conductance close to 42 pS in negative voltage range. In transfected HEK cells loaded with the calcium indicator dye Fura 2, direct activation of CNG channels by 8‐Br‐cGMP increased fluorescence. The signal was blocked by the addition of Mg2+ ions. From these results, it is suggested that the pineal cyclic nucleotide‐gated channel is a good candidate for mediating calcium entry into the pineal photoreceptors. It is most probably a key element in the signalling pathways that control the rhythmic production of melatonin.
The protective effect of melatonin on renal ischemia–reperfusion injury in the rat
Authors: Sener Göksel , Sehirli A. Özer , Keyer‐Uysal Meral , Arbak Serap , Ersoy Yasemin , Yeğen Berrak Ç.
Published: March 2003

Oxygen free radicals are considered to be important components involved in the pathophysiological tissue alterations observed during ischemia–reperfusion (I/R). In this study, we investigated the putative protective effects of melatonin treatment on renal I/R injury. Wistar albino rats were unilaterally nephrectomized and subjected to 45 min of renal pedicle occlusion followed by 1, 3, 6, 24, 48 hr or 1 wk of reperfusion. Melatonin (10 mg/kg, s.c.) or vehicle was administered twice, 15 min prior to ischemia and immediately before the reperfusion period. At the end of the reperfusion periods, rats were decapitated. Kidney samples were taken for histological examination or the determination of renal malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO) activity and protein oxidation (PO). Serum creatinine and blood urea nitrogen (BUN) concentrations were measured for the evaluation of renal function. The results revealed that I/R induced nephrotoxicity, as evidenced by increases in BUN and creatinine levels at each time point, was reversed by melatonin treatment. The decrease in GSH and increases in MDA, MPO and PO induced by I/R indicated that renal injury involves free radical formation. As melatonin administration reversed these oxidant responses, improved renal function and microscopic damage, it seems likely that melatonin protects kidney tissue against oxidative damage.
Normal and pathological adaptations of articular cartilage to joint loading
Authors: Arokoski J. P. A. , Jurvelin J. S. , Väätäinen U. , Helminen H. J.
Published: March 2003

Joints are functional units that transmit mechanical loads between contacting bones during normal daily or specialized activities, e.g., sports. All components of the joint, i.e. articular cartilage, bone, muscles, ligaments/tendons and nerves, participate in load transmission. Failure in any of these components can cause joint malfunction, which, in turn, may lead to accumulation of damage in other joint components. Mechanical forces have great influence on the synthesis and rate of turnover of articular cartilage molecules, such as proteoglycans (PGs). Regular cyclic loading of the joint enhances PG synthesis and makes cartilage stiff. On the other hand, loading appears to have less evident effects on the articular cartilage collagen fibril network. Continuous compression of the cartilage diminishes PG synthesis and causes damage of the tissue through necrosis. The prevailing view is that osteoarthrosis (OA) starts from the cartilage surface through PG depletion and fibrillation of the superficial collagen network. It has also been suggested that the initial structural changes take place in the subchondral bone, especially when the joint is exposed to an impact type of loading. This in turn would create an altered stress pattern on joint surfaces, which leads to structural damage and mechanical failure of articular cartilage. The importance of the neuromuscular system to the initiation and progression of OA is still poorly understood. Many surgical extra‐ and intra‐articular procedures have been used for the treatment of OA. Although some of the new methods, such as autologous chondrocyte transplantation and mosaicplasty, have given good clinical results, it is reasonable to emphasize that the methods still are experimental and more controlled studies are needed.
Effect of stride length on symptoms of exercise‐induced muscle damage during a repeated bout of downhill running
Authors: Eston R. G. , Lemmey A. B. , McHugh P. , Byrne C. , Walsh S. E.
Published: March 2003

The purpose of this study was to assess the effects of changes in stride length on the symptoms of exercise‐induced muscle damage (EIMD) during a repeated bout of downhill running in a group of 18 men and women. Muscle tenderness, plasma creatine kinase activity (CK) and maximal voluntary isometric force were measured before and after two downhill runs, with each run separated by 5 weeks. The first downhill run was at the preferred stride frequency (PSF). Participants were then randomly allocated to one of three sex‐balanced groups with equal numbers of men and women: overstride (−8% PSF), understride (+8% PSF) and normal stride frequency for the second downhill run. Stride length had no effect (P>0.05) on muscle tenderness, CK or isometric peak force. Increases in muscle tenderness (P<0.001) and CK were lower (P<0.05) following the second downhill run, although there was no difference in the pattern and extent of the strength decrement between the two runs. There were also no differences (P>0.05) in muscle tenderness, CK or the relative strength loss between the men and the women. Results suggest that the symptoms of EIMD are unaffected by gender and small alterations to the normal stride pattern during constant velocity downhill running. The observation that muscle tenderness and CK were reduced following a repeated bout of similar eccentric exercise is consistent with the phenomenon known as the ‘repeated bout effect’ of muscle damage.
Effect of acetate on glycogen replenishment in liver and skeletal muscles after exhaustive swimming in rats
Authors: Nakao C. , Yamada E. , Fukaya M. , Tayama K. , Tsukamoto Y. , Sato Y.
Published: March 2003

Immediately after exhaustive swimming, rats were given one of the following orally: distilled water (W), glucose (G); acetic acid (A); citric acid (C); glucose and acetic acid (GA); and glucose and citric acid (GC), and they were killed 2 h after ingestion (each trial: n=4). Exhaustive exercise resulted in a significant reduction of the glycogen store in the gastrocnemius muscle. The glycogen stores in the liver were significantly higher following ingestion in groups GA and GC, in the gastrocnemius in groups G, GA and GC, and in the soleus in group GC, than immediately post exercise. These results suggest that oral acetic acid with glucose can facilitate liver glycogen restoration during the early period of recovery, and that acetate has about the same physiological effects as citrate on glycogen replenishment.
Asymptomatic hypoechoic regions on patellar tendon ultrasound: A 4‐year clinical and ultrasound followup of 46 tendons
Authors: Cook J. L. , Khan K. M. , Kiss Z. S. , Coleman B. D. , Griffiths L.
Published: March 2003

Patellar tendon ultrasound appearance is commonly used in clinical practice to diagnose patellar tendinopathy and guide management. Using a longitudinal study design we examined whether or not the presence of a hypoechoic ultrasonographic lesion in an asymptomatic patellar tendon conferred a risk for developing jumper’s knee compared with a tendon that was ultrasonographically normal. Ultrasonographic, symptomatic and anthropometric assessment was completed at baseline and followup. Magnetic resonance imaging was performed on four tendons that resolved ultrasonographically in the study period. Forty‐six patellar tendons were followed over 47±11.8 months. Eighteen tendons were hypoechoic at baseline and 28 were ultrasonographically normal. Five tendons resolved ultrasonographically in the study period. Magnetic resonance imaging in four of these tendons was normal. Seven normal patellar tendons at baseline developed a hypoechoic area but only two became symptomatic. Analysis of ultrasonography at baseline and clinical outcome with Fisher’s exact test shows there is no association between baseline ultrasound changes and symptoms at followup. In this study there is no statistically significant relationship between ultrasonographic patellar tendon abnormalities and clinical outcome in elite male athletes. Management of jumper’s knee should not be solely based on ultrasonographic appearance; clinical assessment remains the cornerstone of appropriate management.
Maximal strength training improves aerobic endurance performance
Authors: Hoff J. , Gran A. , Helgerud J.
Published: March 2003

The aim of this experiment was to examine the effects of maximal strength training with emphasis on neural adaptations on strength‐ and endurance‐performance for endurance trained athletes. Nineteen male cross‐country skiers about 19.7 ± 4.0 years of age and a maximal oxygen uptake (VO2 max) of 69.4 ± 2.2 mL × kg−1 × min−1 were randomly assigned to a training group (n = 9) or a control group (n = 10). Strength training was performed, three times a week for 8 weeks, using a cable pulley simulating the movements in double poling in cross‐country skiing, and consisted of three sets of six repetitions at a workload of 85% of one repetition maximum emphasizing maximal mobilization of force in the concentric movement. One repetition maximum improved significantly from 40.3 ± 4.5 to 44.3 ± 4.9 kg. Time to peak force (TPF) was reduced by 50 and 60% on two different submaximal workloads. Endurance performance measured as time to exhaustion (TTE) on a double poling ski ergometer at maximum aerobic velocity, improved from 6.49 to 10.18 min; 20.5% over the control group. Work economy changed significantly from 1.02 ± 0.14 to 0.74 ± 0.10 mL × kg−0.67 × min−1. Maximal strength training with emphasis on neural adaptations improves strength, particularly rate of force development, and improves aerobic endurance performance by improved work economy.
Effects of exercise on glycemic control and body mass in type 2 diabetes mellitus: a meta‐analysis of controlled clinical trials
Authors: Boule N. G. , Haddad E. , Kenny G. P. , Wells G. A. , Sigal R. J.
Published: March 2003

Context: Exercise is widely perceived to be beneficial for glycemic control and weight loss in patients with type 2 diabetes. However, clinical trials on the effects of exercise in patients with type 2 diabetes have had small sample sizes and conflicting results. Objective: To systematically review and quantify the effect of exercise on glycosylated hemoglobin (HbA(1c)) and body mass in patients with type 2 diabetes. Data sources: Database searches of MEDLINE, EMBASE, Sport Discuss, Health Star, Dissertation Abstracts and the Cochrane Controlled Trials Register for the period up to and including December 2000. Additional data sources included bibliographies of textbooks and articles identified by the database searches. Study selection: We selected studies that evaluated the effects of exercise interventions (duration ≥ = 8 weeks) in adults with type 2 diabetes. Fourteen (11 randomized and three non‐randomized) controlled trials were included. Studies that included drug cointerventions were excluded. Data extraction: Two reviewers independently extracted baseline and post‐intervention means and SDs for the intervention and control groups. The characteristics of the exercise interventions and the methodological quality of the trials were also extracted. Data synthesis: Twelve aerobic training studies [mean (SD), 3.4 (0.9) times/week for 18 (15) weeks] and two resistance training studies [mean (SD), 10 (0.7) exercises, 2.5 (0.7) sets, 13 (0.7) repetitions, 2.5 (0.4) times/week for 15 (10) weeks] were included in the analyses. The weighted mean post‐intervention HbA(1c) was lower in the exercise groups compared with the control groups (7.65% vs 8.31%; weighted mean difference, 0.66%; P < 0.001). The difference in post‐intervention body mass between exercise groups and control groups was not significant (83.02 kg vs 82.48 kg; weighted mean difference, 0.54; P= 0.76). Conclusion: Exercise training reduces HbA(1c) by an amount that should decrease the risk of diabetic complications, but no significantly greater change in body mass was found when exercise groups were compared with control groups.
Anterior cruciate ligament injuries in young females playing soccer at senior levels
Authors: Söderman K. , Pietilä T. , Alfredson H. , Werner S.
Published: March 2003

The aim of this investigation was to study the consequences of anterior cruciate ligament injuries in female soccer players. Special interest was focused on young female soccer players (< 16 years) sustaining anterior cruciate ligament injuries when playing at a senior level, which means playing together with players 19 years or older. In Sweden, all players belonging to an organized soccer club are insured by the same insurance company, the Folksam Insurance Company. Data of all soccer‐related knee injuries in females reported to the Folksam Insurance Company between 1994 and 1998 were collected. A questionnaire was sent to 978 females who were registered to have sustained a knee injury before the age of 20 years. The response rate was 79%. Three hundred and ninety‐eight female soccer players who had sustained an anterior cruciate ligament injury before the age of 19 years were analysed. Most of their anterior cruciate ligament injuries had been diagnosed using arthroscopy or magnetic resonance imaging (84%). Thirty‐eight percent of the players had been injured before the age of 16 years. Of these, 39% were injured when playing in senior teams. When playing in senior teams 59% of the players below the age of 16 years and 44% of the players 16 years or older sustained their ACL injuries during contact situations. At the time of this investigation (2–7 years after the anterior cruciate ligament injury), altogether 78% (n = 311) reported that they had stopped playing soccer. The most common reason (80%) was symptoms from their anterior cruciate ligament‐injured knee. It appears that many young female soccer players injure their anterior cruciate ligament when playing at a senior level. Therefore, we suggest that female soccer players under the age of 16 years should be allowed to participate only in practice sessions but not games at a senior level.