bluuebunny/crossref_metadata_2025 huggingface dataset:
Possible Role of Vasopressin in the Thermoregulatory Response to Chlorpyrifos in the Rat
Authors: Yang Yong‐Lu , Gordon Christopher J.
Published: March 2003

Abstract: Arginine vasopressin is a naturally occurring antipyretic which is released into the CNS to prevent excessive elevations in body temperature during fever. Circulating levels of arginine vasopressin may also have a role in the tonic control of body temperature. We have found that the organophosphate insecticide chlorpyrifos will raise blood pressure and lower body temperature in the rat. Because arginine vasopressin is a potent hypertensive agent and is capable of lowering core temperature, we suspected that arginine vasopressin may be involved in the thermoregulatory response to chlorpyrifos. To this end, core temperature and motor activity of male and female Sprague‐Dawely rats were monitored before and after treatment with the corn oil vehicle or chlorpyrifos (15 mg/kg in females; 30 mg/kg in males; oral) concomitant with injection of a saline vehicle or a type 1 arginine vasopressin antagonist (20 μg/kg in females; 30 μg/kg in males; intraperitoneally). Rats dosed with chlorpyrifos and saline underwent a 2–3 ° reduction in core temperature >50% decrease in motor activity. The V1 antagonist attenuated the hypothermic effect of chlorpyrifos in both sexes. Chlorpyrifos‐induced inhibition in motor activity was unaffected by the V1 antagonist. In another experiment, the V1 antagonist (30 μg/kg) was co‐administered with saline or 0.2 mg/kg oxotremorine, a muscarinic agonist that stimulates a heat loss response and partially mimics the effects of chlorpyrifos. The V1 antagonist attenuated the hypothermic effect of oxotremorine in both sexes. Plasma arginine vasopressin levels were determined in male rats 3 hr after corn oil or 30 mg/kg chlorpyrifos. There was no significant effect of chlorpyrifos on plasma levels of arginine vasopressin. That the V1 antagonist blocked the hypothermic effect of chlorpyrifos suggests that the thermoregulatory response to chlorpyrifos is mediated by central and/or systemic vasopressin release. The lack of a significant increase in plasma vasopressin after chlorpyrifos suggests that localized release of vasopressin may be involved in the thermoregulatory response to chlorpyrifos.
Behavioural Effects in Rodents of Methyl Angolensate: a Triterpenoid Isolated from Entandrophragma angolense*
Authors: Amos Samson , Orisadipe Abayomi , Binda Lucy , Emeje Martins , Adesomoju Akinbobola , Okogun Joseph , Akah Peter , Wambebe Charles , Gamaniel Karniyus
Published: March 2003

Abstract: Behavioral effects of methyl angolensate were investigated in mice and rats. Spontaneous motor activity, pentobarbital sleeping time, amphetamine‐stereotyped behaviour, exploratory activity and apomorphine – induced climbing studies in mice were evaluated. The results revealed that methyl angolensate reduced spontaneous motor activity in mice, prolonged the duration of pentobarbital sleeping time in rats and attenuated amphetamine‐induced stereotype behaviour in rats. Methyl angolensate also decreased exploratory activity in mice and reduced the rate of apomorphine‐induced climbing in mice at the doses tested. It is suggested that methyl angolensate possesses some biologically active principles that are sedative in nature.
Beneficial Effects of Trandolapril in Uninephrectomized Spontaneously Hypertensive Rats: Role of Cyclooxygenase Pathway
Authors: López‐Hernández Francisco J. , Carrón Rosalía , Montero María J.
Published: March 2003

Abstract: The antihypertensive efficacy of the angiotensin‐converting enzyme inhibitor trandolapril was evaluated in uninephrectomized spontaneously hypertensive rats. After 5 weeks of treatment, blood pressure, cardiac and aortic mass, as well as the functional status of the aortic endothelium, and the role played by the cyclooxygenase pathway were investigated. In addition, the effect of a sub‐antihypertensive dose of the calcium antagonist verapamil, in combination with trandolapril, was also investigated. As compared to placebo, trandolapril returned blood pressure and aortic lamina media cross sectional area to normotensive values, significantly reduced the heart‐to‐body weight, and improved the acetylcholine‐induced relaxation of aortic rings. This latter effect is thought to be mediated by the elimination of a substance derived from the cyclooxygenase pathway. Verapamil, in single therapy, did not reduce blood pressure, or heart‐to‐body weight, increased aortic lamina media cross sectional area and impaired acetylcholine‐induced relaxation. When combined with trandolapril in dual therapy, some of the beneficial effects of trandolapril remained, whereas others were counterbalanced by verapamil. In conclusion, trandolapril proved to be an effective therapeutic drug in this animal model of hypertension. Combination of trandolapril with a sub‐antihypertensive dose of verapamil did not show any positive synergistic effect; on the contrary, it outweighed some of the beneficial effects of trandolapril.
Antidiabetogenic Effect of Fusidic Acid in Diabetes Prone BB Rats: A Sex‐Dependent Organ Accumulation of the Drug is Seen
Authors: Hageman Ida , Buschard Karsten
Published: March 2003

Abstract: Fusidic acid and its sodium salt (fusidin) are widely used antistaphylococcal drugs which possesses immunomodulatory properties. This prompted us to investigate whether high concentrations of fusidin could lower the diabetes incidence in diabetes‐prone BB (BioBreeding) rats. As fusidin has previously been claimed to be poorly absorbed in rats after oral administration we wanted to measure the activity of the drug in various organs. Three groups of BB rats were used: 63 rats received fusidin dissolved in drinking water; 65 rats received chow containing fusidin; and 72 rats served as controls. The content of fusidin in the organs were examined microbiologically. The incidence of diabetes was significantly lower in the two fusidin‐treated groups compared to the control group. The incidence was lower for male than for female rats in both experimental groups while no gender difference was seen in the control group. The female rats had a substantially higher content of fusidin in their organs than the males regardless of the administration way and regardless of diabetes outbreak or not. Interestingly, the fusidin treated non‐diabetic rats displayed a lower random blood glucose level than the controls. In conclusion, fusidin is well absorbed after oral administration and it significantly reduces the diabetes incidence in BB rats. Fusidin accumulates substantially more in female rats which may be due to the steroid structure of fusidin. Whether the same phenomenon takes place in human beings is not known.
Tanning salons in southwest Poland: a survey of safety standards and professional knowledge of the staff
Authors: Szepietowski Jacek C. , Nowicka Danuta , Soter Katarzyna , Strzelecka Ewa , Kozera Marzena , Salomon Joanna
Published: March 2003

Background: Nowadays, sunbeds are very popular worldwide; however – in the majority of countries, including Poland – there are no general guidelines and/or regulations for sunbed usage.

Purpose: The aim of the study was to evaluate tanning salons in southwest Poland, paying special attention to safety regulations and basic professional knowledge of the staff members of these units. The hypothesis was put that tanning salons offer better skin and eye protection if their employees are more educated.

Methods: Fifty‐five sunbed units were visited by the investigators, acting as potential clients. Information was obtained from the staff members in response to previously designed questionnaire.

Results: Employees of 41.8% of sunbed units had adequate knowledge of radiation used in their establishments. Goggles were provided in 72.7%, sunglasses in additional 25.5% of salons. Lotions with sunscreens were available in 41.8% of units. Brief medical history of the client was taken in 20% of units. No dermatological examination was performed. Tanning salons, where employed staff were well‐orientated in ultraviolet radiation emitted in their units, significantly more frequently recommended usage of goggles and sunscreens (P = 0.0037 and P = 0.0033, respectively). Moreover, in these establishments sunscreens were more commonly available (P = 0.0029).

Conclusions: The knowledge of staff members of tanning salons is poor and the eye and skin protection is not enough. The results point out the importance of the knowledge of the staff members in providing skin and eye protection.
Cyclosporin‐A suppresses p53‐dependent repair DNA synthesis and apoptosis following ultraviolet‐B irradiation
Authors: Sugie N. , Fujii N. , Danno K.
Published: March 2003

Background: The combination of cyclosporin‐A (CS‐A) and ultraviolet‐B (UV‐B) irradiation is not recommended in the treatment of psoriasis, because risks of UV‐B‐induced skin cancer are increased. The recommendation, however, has not well been confirmed by basic researches.

Purpose: In this study, we investigated the effects of CS‐A on UV‐B‐induced repair DNA synthesis, apoptosis and p53 expression.

Methods: Following the short‐term administration of CS‐A (5 and 50 mg/kg/day) or vehicle (V) alone, female BALB/c mice, 8–10 weeks old, were treated with UV‐B irradiation (100 and 500 mJ2 cm) or tape stripping (TS). After the treatment, the effects of CS‐A on the increased rate of epidermal DNA synthesis were examined by using 5′‐bromodeoxyuridine (BrdU) pulse‐labelling techniques. In separate experiments, the effects of CS‐A on the number of sunburn cells, nick‐end labelling +  cells and p53 + cells were examined 24 h after UV‐B irradiation.

Results: Cyclosporin‐A significantly suppressed the UV‐B‐induced increase in BrdU uptake, which occurs to repair DNA damage, while there were no significant effects on the stripping (S)‐induced increase or the rate of normal epidermal proliferation, which is not associated with any DNA injuries. The number of sunburn cells, nick‐end labelling +  cells and p53 +  cells was significantly reduced by pretreatment with CS‐A.

Conclusion: Cyclosporin‐A interferes with the self‐ protective mechanisms involved in both repair and apoptotic removal of UV‐B‐induced DNA damage. The loss of p53 expression is responsible for the effects of CS‐A.
Melatonin protects against oxidized low‐density lipoprotein‐induced inhibition of nitric oxide production in human umbilical artery
Authors: Wakatsuki Akihiko , Okatani Yuji , Ikenoue Nobuo , Shinohara Koichi , Watanabe Kazushi , Fukaya Takao
Published: March 2003

We evaluated the antioxidative effect of melatonin on the oxidized low‐density lipoprotein (LDL)‐induced impairment of nitric oxide (NO) production in human umbilical artery, which may be the prime cause of endothelial dysfunction in pre‐eclampsia. Umbilical artery sections with intact endothelium were obtained from healthy pregnant women who were delivered between 37 and 40 wk of gestation. The production of NO in the umbilical arteries was stimulated by adding l‐arginine followed by incubation for 60 min. NO concentrations were estimated by measuring nitrite ions (NO2−) using high‐performance liquid chromatography. LDL was oxidized by incubation with 5 μM CuSO4 at 37°C for 4 hr, followed by dialysis at 4°C for 24 hr. Prior to the addition of l‐arginine, the segments were treated with native or oxidized LDL (0, 50, 100, 200, 400 μg/mL), or were pre‐treated with either mannitol (50 mM) or melatonin (20, 100, 500 μM) before adding oxidized LDL. Changes in l‐arginine‐induced NO2− production were expressed as a percentage of NO2− production at the end of pre‐incubation. Treatment with oxidized LDL significantly reduced l‐arginine‐induced NO2− production (P<0.05), while NO2− production did not change by incubation with native LDL. Pre‐treatment with melatonin significantly increased NO2− production that had been decreased by oxidized LDL (P<0.05). Similarly, pre‐treatment with mannitol reversed the oxidized LDL‐induced reduction in NO2− production (P<0.05). These results indicate that melatonin protects against oxidized LDL‐induced inhibition of NO production in the endothelium of human umbilical arteries, most likely through its ability to scavenge hydroxyl radicals.
Effect of melatonin on changes in hepatic antioxidant enzyme activities in rats treated with α‐naphthylisothiocyanate
Authors: Ohta Yoshiji , Kongo Mutsumi , Kishikawa Teruaki
Published: March 2003

We have reported that melatonin protects against α‐naphthylisothiocyanate (ANIT)‐induced acute liver injury in rats by preventing enhanced lipid peroxidation. Herein, we examine the effect of melatonin on hepatic antioxidant enzyme activities in rats with a single i.p. injection of ANIT (75 mg/kg body weight) in order to clarify the protective mechanism of the indoleamine against ANIT‐induced acute liver injury. Rats received a single oral administration of melatonin (10 or 100 mg/kg body weight) at 12 hr after ANIT treatment. Hepatic Cu,Zn‐superoxide dismutase (Cu,Zn‐SOD), Mn‐superoxide dismutase (Mn‐SOD), catalase (CAT), Se‐glutathione peroxidase (Se‐GSH‐Px), glutathione reductase (GSSG‐R), and glucose‐6‐phosphate dehydrogenase (G‐6‐PDH) activities and reduced glutathione (GSH) concentration were determined 12 and 24 hr after ANIT treatment. ANIT‐treated rats showed decreases in hepatic Cu,Zn‐SOD and GSSG‐R activities at 24 hr after treatment, transient increases in hepatic CAT and Se‐GSH‐Px activities at 12 hr, and no changes in hepatic Mn‐SOD and G‐6‐PDH activities at 12 or 24 hr. Only the high dose of melatonin attenuated the decrease in hepatic Cu,Zn‐SOD activity, while both doses of the indoleamine almost completely attenuated the decrease in hepatic GSSG‐R activity. Neither dose of melatonin affected hepatic CAT, Se‐GSH‐Px, and G‐6‐PDH activities. ANIT‐treated rats showed an increase in hepatic GSH concentration at 24 hr after treatment. Neither dose of melatonin affected the increase in hepatic GSH concentration. These results indicate that orally administered melatonin prevents decreases in Cu,Zn‐SOD and GSSG‐R activities in the liver of ANIT‐treated rats, and suggest that the indoleamine may protect against ANIT‐induced acute liver injury by attenuating the disruption of hepatic antioxidant defense systems.
Melatonin protects against copper‐mediated free radical damage
Authors: Parmar Paresh , Limson Janice , Nyokong Tebello , Daya Santy
Published: March 2003

Copper is an essential trace element which forms an integral component of many enzymes. While trace amounts of copper are needed to sustain life, excess copper is extremely toxic. Copper has been implicated in various neurodegenerative disorders, such as Wilson's and Alzheimer's diseases. Previous studies showed that melatonin, the principle secretory product of the pineal gland, binds Cupric chloride (Cu2+) and that this may have implications in copper‐induced neurodegenerative diseases. In the present study, in vitro copper‐mediated lipid peroxidation was induced. Melatonin (5 mM) protected against copper‐mediated lipid peroxidation in liver homogenates. Electron micrographs of in vivo administered Cu2+and melatonin show that melatonin affords some protection to rat hepatocytes in the presence of copper. Electrochemical studies performed show that melatonin, in addition to binding Cu2+, may provide protection against copper‐mediated free radical damage by binding Cu1+. The findings of these studies provide further evidence for the neuroprotective role of melatonin.
Effects of pinealectomy on the levels and the circadian rhythm of plasma homocysteine in rats
Authors: Baydas Giyasettin , Gursu M. Ferit , Cikim Gurkan , Canpolat Sinan , Yasar Abdullah , Canatan Halit , Kelestimur Haluk
Published: March 2003

Abstract: Hyperhomocysteinemia is an independent cardiovascular risk factor. There are several factors including aging that contribute to the development of hyperhomocysteinemia. Nevertheless, the exact mechanisms causing this condition are still debated. We hypothesize that the age‐related decrease in melatonin levels may be consequential in hyperhomocysteinemia. Recently, we found that plasma homocysteine (Hcy) levels are increased in pinealectomized (PINX) rats and melatonin reverses this increase. The aim of the present study was to determine if there is a circadian rhythm of plasma Hcy in rats and to examine the effect of pinealectomy on this cycle. Plasma Hcy levels demonstrated a 24‐hr rhythm with a peak at 02:00 hr and a nadir at 14:00 hr in both control and PINX rats. Pinealectomy did not change the phase of the rhythm or the nocturnal elevation of plasma Hcy, but it did significantly increase mean plasma Hcy levels compared with those in controls and in rats that were sham pinealectomized (sPINX) (P < 0.05). Melatonin decreases plasma Hcy levels while causing an increase in total glutathione (tGSH). In conclusion, we speculate that decreasing levels of melatonin during aging lead to hyperhomocysteinemia and a decrease in tGSH and the latter may be one of the factors causing hyperhomocysteinemia in the elderly population.
Effect of salbutamol, a beta‐2‐adrenergic agonist, on erythropoietin concentration in healthy males
Authors: Berglund B. , Sundgot‐Borgen J. , Wide L.
Published: March 2003

Fifteen healthy males, aged 20–30 years, participated in a double‐blind cross‐over study on the effect of the beta‐2 stimulator salbutamol on erythropoietin concentration and hemoglobin concentration. The treatment period comprised inhalation of salbutamol, 0.8 mg four times daily for 2 weeks. Serum‐erythropoietin was essentially unaltered after treatment with salbutamol, 9.5±4.94 IU  ·  l−1 (mean±SD), as compared to both control situation, 9.2±4.50 IU  ·  l−1(mean±SD), and placebo treatment (9.7±4.07 IU  ·  l−1) (mean±SD). The same pattern, no significant changes between control situation and treatment with salbutamol or placebo, also applied to hemoglobin concentration. In conclusion, it is not possible to increase erythropoietin concentration and thereby erytropoiesis by inhalation of high doses of the International Olympic Committee (IOC) approved beta‐2 stimulator salbutamol for 2 weeks in healthy young males.
Simple objective measurement of the cutaneous delayed‐type hypersensitivity reaction to tuberculin using spectrophotometry
Authors: Chambers Mark A. , Jahans Keith , Whelan Adam , Hughes Catherine , Sayers Robin , Perkins Alan , Glyn Hewinson R.
Published: March 2003

Background/aims:  A number of subjective methods have been used to quantify the extent of the cutaneous delayed‐type hypersensitivity (DTH) reaction. However, because of their subjective nature, significant differences in measurements may be seen between individual observers or laboratories unless thorough training is given to each observer.

Methods:  Objective measurement of the DTH reaction using a hand‐held spectrophotometer is described. Guinea pigs were primed using inoculation with Mycobacterium bovis Bacille Calmette‐Guerin and challenged five weeks later in the shaved flank with three doses of bovine purified protein derivative. The extent of the ensuing DTH reaction was measured 24 and 48 h later. Spectrophotometric measurement of the reaction site was compared with a control region of skin on each animal and expressed as the change within a standard colour space. Data obtained with the spectrophotometer was compared with the subjective measurement of the area of the DTH reaction by an experienced operator.

Results: T he measurements obtained with the spectrophotometer correlated very closely with conventional measurement of the reaction area by a trained operator. The reaction size in square mm and changes along the red/green colour axis was correlated most strongly.

Conclusion:  Spectrophotometric measurement of the DTH reaction had advantages over conventional measuring techniques in terms of speed, reproducibility and reduced operator to operator variation. We conclude that the cutaneous DTH reaction may be simply and objectively quantified with the use of a hand‐held spectrophotometer.
Assessment of collagen lattice thickness by B‐scan echography
Authors: Viennet C. , Degouy A. , Bride J. , Humbert P.
Published: March 2003

Background/aims:  Collagen lattices are an in vitro dermal equivalent that has led to the development of an original model of dermal tissue. Fibroblasts cultured in three‐dimensions in a collagen matrix differentiate similarly to in vivo. New technological performances in ultrasonic imaging can now provide precise measurements of tissue thickness with good resolution. The aim of this study was to assess, by B‐scan echography, the correlation between collagen lattice thickness and various collagen and cell concentrations.

Methods:  Three concentrations of human dermal fibroblasts (F1 = 8.105 C/mL, F2 = 16.105 C/mL, F3 = 32.105 C/mL) and three concentrations of rat tail collagen (C1 = 2 mg mL−1, C2 = 3 mg mL−1, C3 = 4 mg mL−1) were prepared for five different kinds of collagen lattices: F2C1, F2C2, F2C3, F1C1 and F3C1 (n = 5 per case). Ultrasonic imaging was performed on day 0, 4, 6, 10, 12 and 14 using a Dermcup® 2020 scanner. The scans measured thickness in the centre and periphery of the lattice.

Results:  The collagen lattice echogenicity was similar to a dermis in vivo. For each assessment, the collagen lattice thickness increased until day 12 and then stabilized. The lattice was thicker when the cellular concentration was higher, (at day 14: F1C1 = 0.66 mm, F2C1 = 0.86 mm, F3C1 = 1.21 mm). The collagen concentration did not significantly influence lattice thickness.

Conclusion:  Collagen lattice thickness increased with retraction time and cellular concentration.
Benign dermoscopic network patterns in dysplastic melanocytic nevi
Authors: Troyanova Petranka
Published: March 2003

Background/aims: Epiluminescence microscopy (ELM) is a non‐invasive clinical technique, which by employing the optical phenomenon of oil immersion makes surface structures of the skin accessible for in vivo examination and provides additional criteria for the diagnosis of pigment skin lesions (PSLs). Many ELM criteria have been described. One of the most important ELM criteria is the pigment network (PN).

Objective: The aim of this study is to identify benign ELM (dermoscopic) network patterns of dysplastic melanocytic nevi (DMN).

Methods: This study included 907 dysplastic melanocytic nevi in 178 patients. Prior to biopsy, each lesion was photographed with oil immersion, and the images were viewed on a high‐resolution compact slide projector. For each PSL, the ELM Network Features and ABCD‐score were evaluated.

Results and discussion: The benign dermoscopic network features in DMN are the presents of a regular PN with delicate lines and margins, which predominantly thins out at the border of the lesion. For DMN, with these features, the mean ABCD score is smaller than ABCD‐score for DMNs with irregular, prominent PN and network patches, ending abruptly at the periphery. In DMN with a network predominantly thinning out at the border of the lesion several uniform network patterns were found—diffuse network pattern, patchy network pattern, structureless center pattern, globular center pattern, and pigmented‐blotch center pattern.

Conclusions: Benign features of pigment network are regularity, delicacy and thinning out at the border of the lesion. Benign dermoscopic network patterns are diffuse network pattern, patchy network pattern, structureless center pattern, globular center pattern, and pigmented‐blotch center pattern. They can be found in DMN with a network predominantly thinning out at the border of the lesion.
Validation and clinical relevance of a novel scalp coverage scoring method
Authors: Van Neste Dominique , Leroy Thérèse , Sandraps Emmanuelle
Published: March 2003

Background/aims: Distinctive patterns of defective scalp skin coverage or alopecia have been identified by clinicians but do not help measuring the dynamics of hair changes over time. Hence, we conceived the scalp coverage scoring (SCS) method that integrates cumulative changes of hair growth or loss. In this paper, we report the results of validation studies demonstrating that the SCS can be applied in real time in the clinic or on global photographs for evaluating the severity of androgenetic alopecia (AGA) of male subjects and for monitoring changes over time.

Methods: Different panels totalling 38 different male subjects with AGA were classified according to a modified Norwood–Hamilton scale and were evaluated with the SCS system (real time or global photographs). The contrast‐enhanced phototrichogram method (CE‐PTG), a refined non‐invasive and validated analytical technique was used for calibration purposes.

Results: The real time SCS was correlated with SCS on global photographs. The inter‐ and intra‐observer variation of SCS obtained on global photographs was less than 3%. The real time SCS was negatively correlated with the clinical staging of male pattern baldness according to the modified Norwood–Hamilton scale, confirming less scalp coverage in more severly affected subjects. In 12 male subjects with AGA, after SCS evaluation of the top of the head, a 1‐cm2 central target site was explored with CE‐PTG. There was a significant correlation of real time SCS with the percentage of thick anagen hair (r = 0.53; P < 0.08) and with the density of thin hair (r = −0.68; P < 0.02). Changes over time as documented on global photographs (18 subjects at baseline and after 12 and 60 months) were rated by a panel of independent experts (paired photographs) who were not blinded as to time. Randomised individual photographs were also examined one at a time for SCS. This procedure documents data obtained without control of baseline photographs and establishes blinding as to time. The changes calculated from SCS (after – baseline) were correlated (r = 0.9; P < 0.0001) with the rating of the panel of experts.

Conclusions: When minimum technical precautions are taken prior to the scoring session, the main points of interest of the SCS method are:

Non‐invasive quantitative and reproducible technique

Measures dynamics of scalp hair growth and loss

Easily applied in the hair clinic.
Mammalian Tumor Susceptibility Gene 101 (TSG101) and the Yeast Homologue, Vps23p, Both Function in Late Endosomal Trafficking
Authors: Babst Markus , Odorizzi Greg , Estepa Eden J. , Emr Scott D.
Published: March 2003

The mammalian tumor susceptibility gene tsg101 encodes the homologue of Vps23p, a class E Vps protein essential for normal membrane trafficking in the late endosome/multivesicular body of yeast. Both proteins assemble into large (∼350 kDa) cytosolic protein complexes and we show that the yeast complex contains another class E Vps protein, Vps28p. tsg101 mutant cells exhibit defects in sorting and proteolytic maturation of the lysosomal hydrolase cathepsin D, as well as in the steady‐state distribution of the mannose‐6‐phosphate receptor. Additionally, endocytosed EGF receptors that are normally sorted to the lysosome are instead rapidly recycled back to the cell surface in tsg101 mutant cells. We propose that tsg101 mutant cells are defective in the delivery of cargo proteins to late endosomal compartments. One consequence of this endosomal trafficking defect is the delayed down‐regulation/degradation of activated cell surface receptors, resulting in prolonged signaling. This may contribute to the tumorigenic phenotype exhibited by the tsg101 mutant fibroblasts.
Generation of MHC Class I Peptide Antigens by Protein Processing in the Secretory Route by Furin
Authors: Gil‐Torregrosa Beatriz C. , Castaño A. Raúl , López Daniel , Del Val Margarita
Published: March 2003

Cytosolic degradation of endogenously synthesized proteins by the proteasome and translocation of processed peptides to the endoplasmic reticulum by the transporters associated with antigen presentation constitutes the classical route for antigen presentation by MHC class I proteins. We have previously defined an alternative pathway in the secretory route involving proteolytic maturation of precursor proproteins for chimeric hepatitis B virus secretory core protein HBe containing a class I epitope at its carboxy‐terminus. We extend those results by demonstrating that intracellular delivery of the trans‐Golgi network protease furin increases both proteolytic maturation and antigen presentation of the chimeric HBe proteins. An additional class I epitope from the HIV envelope gp160 protein was inserted into this COOH‐terminal region of two different chimeric HBe proteins. This epitope was also presented to CTL in a transporter‐independent manner involving furin, and protein maturation and antigen presentation were also enhanced by furin over‐expression. Presentation of this second epitope was restricted by a different class I allele, thus suggesting that antigen presentation by this new pathway may apply to any antigenic epitope and class I molecule. These results define the furin proteolytic maturation pathway of HBe in the secretory route as a general antigen processing route for MHC class I presentation.
Membrane Traffic in Sphingolipid Storage Diseases
Authors: Pagano Richard E. , Puri Vishwajeet , Dominguez Michel , Marks David L.
Published: March 2003

In this review, we summarize our studies of membrane lipid transport in sphingolipid storage disease (SLSD) fibroblasts. We recently showed that several fluorescent SL analogs were internalized from the plasma membrane predominantly to the Golgi complex of normal cells, while in ten different SLSD cell types, these lipids accumulated in endosomes and lysosomes (The Lancet 1999;354: 901–905). Additional studies showed that cholesterol homeostasis is perturbed in multiple SLSDs secondary to SL accumulation and that mistargeting of SL analogs was regulated by cholesterol (Nature Cell Biol 1999;1: 386–388). Based on these findings, we hypothesize that endogenous sphingolipids, which accumulate in SLSD cells due to primary defects in lipid catabolism, result in an altered intracellular distribution of cholesterol, and that this alteration in membrane composition then results in defective sorting and transport of SLs. The importance of SL/cholesterol interactions and potential mechanisms underlying the regulation of lipid transport and targeting are also discussed. These studies suggest a new paradigm for regulation of membrane lipid traffic along the endocytic pathway and could have important implications for future studies of protein trafficking as well as lipid transport. This work may also lead to important future clinical developments (e.g. screening tests for SLSD, new methodology for screening drugs which abrogate lipid storage, and possible therapeutic approaches to SLSD).
Signaling on the Endocytic Pathway
Authors: McPherson Peter S. , Kay Brian K. , Hussain Natasha K.
Published: March 2003

Ligand binding to receptor tyrosine kinases and G‐protein‐coupled receptors initiates signal transduction events and induces receptor endocytosis via clathrin‐coated pits and vesicles. While receptor‐mediated endocytosis has been traditionally considered an effective mechanism to attenuate ligand‐activated responses, more recent studies demonstrate that signaling continues on the endocytic pathway. In fact, certain signaling events, such as the activation of the extracellular signal‐regulated kinases, appear to require endocytosis. Protein components of signal transduction cascades can assemble at clathrin coated pits and remain associated with endocytic vesicles following their dynamin‐dependent release from the plasma membrane. Thus, endocytic vesicles can function as a signaling compartment distinct from the plasma membrane. These observations demonstrate that endocytosis plays an important role in the activation and propagation of signaling pathways.
Mitotic Golgi is in a Dynamic Equilibrium Between Clustered and Free Vesicles Independent of the ER
Authors: Jesch Stephen A. , Mehta Amy J. , Velliste Meel , Murphy Robert F. , Linstedt Adam D.
Published: March 2003

Golgi inheritance during cell division involves Golgi disassembly but it remains unclear whether the breakdown product is dispersed vesicles, clusters of vesicles or a fused ER/Golgi network. Evidence against the fused ER/Golgi hypothesis was previously obtained from subcellular fractionation studies, but left concerns about the means used to obtain and disrupt mitotic cells. Here, we performed velocity gradient analysis on otherwise untreated cells shaken from plates 9 h after release from an S‐phase block. In addition, we used digitonin and freeze/thaw permeabilization as alternatives to mechanical homogenization. Under each of these conditions, approximately 75% of the Golgi was recovered in a population of small vesicles that lacked detectable ER. We also used multilabel fluorescent microscopy with optical sectioning by deconvolution to compare the 3D metaphase staining pattern of endogenous Golgi and ER markers. Although both ER and Golgi staining were primarily diffuse, only the ER was excluded from the mitotic spindle region. Surprisingly, only 2% of the Golgi fluorescence was present as resolvable structures previously characterized as vesicle clusters. These were not present in the ER pattern. Significantly, a portion of the diffuse Golgi fluorescence, presumably representing dispersed 60‐nm vesicles, underwent an apparent rapid aggregation with the larger Golgi structures upon treatments that impaired microtubule integrity. Therefore, mitotic Golgi appears to be in a dynamic equilibrium between clustered and free vesicles, and accurate partitioning may be facilitated by microtubule‐based motors acting on the clusters to insure random and uniform distribution of the vesicles.
Organelle Acidification and Disease
Authors: Weisz Ora A.
Published: March 2003

A subset of cellular compartments maintain acidic interior environments that are critical for the specific functions of each organelle and for cell growth and survival in general. The pH of each organelle reflects the balance between proton pumping, counterion conductance, and proton leak. Alterations in steady‐state organelle pH due to defects in either proton pumping activity or counterion conductance have been suggested to contribute to the pathology of several diseases; however, definitive evidence remains elusive. This review describes recent evidence for the misregulation of organelle pH in the progression of cancer, Dent's disease, and cystic fibrosis.
Clostridial deep neck infection developed after extraction of a tooth: a case report and review of the literature in Japan
Authors: Nakamura S , Inui M , Nakase M , Kamei T , Higuchi Y , Goto A , Tagawa T
Published: March 2003

A rare case of severe deep neck infection caused by clostridia after extraction of the left lower canine is presented. The patient was a 63‐year‐old Japanese woman who had a history of diabetes. The pertinent literature in Japan is reviewed and discussed.
Parkin binds the Rpn10 subunit of 26S proteasomes through its ubiquitin‐like domain
Authors: Sakata Eri , Yamaguchi Yoshiki , Kurimoto Eiji , Kikuchi Jun , Yokoyama Shigeyuki , Yamada Shingo , Kawahara Hiroyuki , Yokosawa Hideyoshi , Hattori Nobutaka , Mizuno Yoshikuni , Tanaka Keiji , Kato Koichi
Published: March 2003

Parkin, a product of the causative gene of autosomal‐recessive juvenile parkinsonism (AR‐JP), is a RING‐type E3 ubiquitin ligase and has an amino‐terminal ubiquitin‐like (Ubl) domain. Although a single mutation that causes an Arg to Pro substitution at position 42 of the Ubl domain (the Arg 42 mutation) has been identified in AR‐JP patients, the function of this domain is not clear. In this study, we determined the three‐dimensional structure of the Ubl domain of parkin by NMR, in particular by extensive use of backbone 15 N‐1 H residual dipolar‐coupling data. Inspection of chemical‐shift‐perturbation data showed that the parkin Ubl domain binds the Rpn10 subunit of 26S proteasomes via the region of parkin that includes position 42. Our findings suggest that the Arg 42 mutation induces a conformational change in the Rpn10‐binding site of Ubl, resulting in impaired proteasomal binding of parkin, which could be the cause of AR‐JP.
Thyrotropin‐Releasing Hormone‐Induced Down‐Regulation of Pyroglutamyl Aminopeptidase II Activity Involves l‐Type Calcium Channels and Cam Kinase Activities in Cultures of Adenohypophyseal Cells
Authors: Vargas M. A. , Cisneros M. , Joseph‐Bravo P. , Charli J.‐L.
Published: March 2003

Released thyrotropin‐releasing hormone (TRH) is inactivated by a narrow specificity ectopeptidase, pyroglutamyl aminopeptidase II (PPII), present in brain and lactotrophs. Various hypothalamic/paracrine factors, including TRH, slowly (in hours) regulate the activity of PPII on the surface of adenohypophyseal cells. TRH‐induced down‐regulation was mimicked by protein kinase C (PKC) activation but was not affected by inhibition of PKC. Adenylate cyclase activation can also down‐regulate PPII. The purpose of this study was to identify elements of the transduction pathway used by TRH to regulate PPII activity. In primary cultures of female adenohypophyseal cells, activation of the stimulatory G protein or adenylate cyclase produced an effect additive to that of TRH; inhibition of protein kinase A activity did not interfere with TRH action. However, regulation of PPII activity by TRH was inhibited by a phospholipase C β inhibitor or chelation of intracellular calcium. l‐type calcium channels (LCC) agonists mimicked TRH action and their effect was not additive with that of TRH. Antagonists of LCC channels and inhibitors of calmodulin or calcium/calmodulin‐dependent protein kinase blocked TRH action. Therefore, TRH‐induced calcium entry through l‐type calcium channels and the activity of calcium/calmodulin‐dependent protein kinase are required for TRH effect on PPII activity in primary cultures of adenohypophyseal cells. This pathway may coregulate PPII and prolactin biosynthesis in response to TRH.
Naturally Occurring Differences in Maternal Care are Associated with the Expression of Oxytocin and Vasopressin (V1a) Receptors: Gender Differences
Authors: Francis D. D. , Young L. J. , Meaney M. J. , Insel T. R.
Published: March 2003

Variations in maternal care have been associated with long‐term changes in neurochemistry and behaviour in adult rats. Rats receiving high levels of licking and grooming as pups are less fearful and more maternal than rats receiving low levels of maternal licking and grooming. Central pathways for oxytocin and vasopressin have been implicated in the neurobiology of anxiety and social behaviours. We assessed whether variations in maternal care were associated with differences in oxytocin receptors (OTR) or vasopressin (V1a) receptors in the brains of adult offspring. In the central nucleus of the amygdala and bed nucleus of the stria terminalis, OTR binding was increased in adult females, but not adult males, that had received high levels of maternal licking and grooming as pups. Conversely, amygdala V1a receptor binding was increased in males, but not females, that had received high levels of maternal licking and grooming. These findings suggest that variations in maternal care may influence the expression of oxytocin and vasopressin receptors in a gender‐specific manner.
Y1 Receptor Activation is Involved in the Effect of Exogenous Neuropeptide Y on Pup Growth and the Early Termination of Lactational Diestrus in the Postpartum Rat
Authors: Toufexis D. J. , Yorozu S. , Woodside B.
Published: March 2003

The effect of chronic administration of exogenous neuropeptide Y (NPY) and specific NPY receptor agonists and antagonists on reproductive function was examined in lactating rats. As previously demonstrated in our laboratory, chronic (7‐day) intracerebroventricular (i.c.v.) NPY infusion (6 µg/day) from days 8–15 postpartum (pp) caused a significant decrease in milk production and an early termination of lactational diestrus. Similar application of the mixed Y1/Y4/Y5 receptor agonist (Leu31, Pro34) NPY (at 3, 6 and 9 µg/day) reproduced the effect of chronic NPY infusion on milk production in a dose‐independent manner. Consistent with this effect, the potent Y1 antagonist/Y4 agonist, 1229U91, given concomitantly with NPY eliminated the decline in milk production. The Y2 receptor agonist, NPY13–36, had no effect on milk production at any of the doses used. Length of lactational diestrus was reduced following administration of the Y2 agonist at 18 µg/day but not at 9 µg or 27 µg/day whereas (Leu31, Pro34) NPY infusion had no effect on this parameter at any of the doses used. However, the group that was treated with NPY plus 1229U91 exhibited the usual length of lactational diestrus, indicating that there is at least some Y1 involvement in the effects of NPY on lactational infertility. To test the possibility that the effects of NPY infusion are mediated through changes in circulating prolactin and progesterone, plasma concentrations of these hormones were measured on day 15 pp in NPY‐, (Leu31, Pro34) NPY‐ and vehicle‐treated females. NPY‐infused females had lower plasma prolactin concentrations than vehicle‐infused dams but progesterone concentrations were similar across groups. Overall, these data indicate that chronic exogenous NPY‐infusion in lactating females disrupts milk production and shortens lactational diestrus, most likely through reducing prolactin secretion, and that this effect is mediated via Y1 receptor activity.
Fc receptor regulation of protective immunity against Chlamydia trachomatis
Authors: Moore Terri , Ananaba Godwin A. , Bolier Jacqueline , Bowers Samera , Belay Tesfaye , Eko Francis O. , Igietseme Joseph U.
Published: March 2003

The prevailing paradigm for designing potentially efficacious vaccines against the obligate intracellular bacterium, Chlamydia trachomatis, advocates regimens capable of inducing a mucosal antigen‐specific T helper type 1 (Th1) response. However, recent reports indicate that rapid and efficient clearance of a secondary infection also requires certain B‐cell functions. We investigated the hypothesis that Fc receptor (FcR)‐mediated antibody effector mechanisms are important B‐cell‐related functions involved in controlling a chlamydial genital reinfection. Microbiological analysis of genital chlamydial infection in FcR knockout (FcRKO) mice lacking the activatory FcγRI (CD64) and FcRγIII (CD16), as well as the inhibitory FcγRIIB1 (CD32), revealed a greater intensity of secondary infection (i.e. bacterial shedding) in FcR−/− as compared to FcR+/+ mice; however, the course of the primary infection was indistinguishable in both animals. Pathologically, FcRKO mice suffered greater ascending infection than immunocompetent wild‐type (WT) mice after a secondary infection. Immunological evaluation indicated that the presence of specific anti‐chlamydial antibodies enhanced chlamydial antigen presentation for induction of a Th1 response by FcR+/+, but not FcR−/−, antigen‐presenting cells. In addition, specific anti‐chlamydial antibodies augmented both macrophage killing of infected epithelial cells by antibody‐dependent cellular cytotoxicity (ADCC) and macrophage inhibition of productive growth of chlamydiae in co‐cultures. These results indicate that B cells participate in anti‐chlamydial immunity via FcR‐mediated effector functions of antibodies, which are operative during reinfections. Such effector functions include ADCC, and possibly enhanced uptake, processing and presentation of chlamydial antigens for rapid induction of a Th1 response, all facilitating the early clearance of an infection. These findings suggest that a future anti‐chlamydial vaccine should elicit both humoral and T‐cell‐mediated immune responses for optimal memory response and vaccine efficacy.
Unequal competitor ideal free distributions: predictions for differential effects of interference between habitats
Authors: Humphries Stuart , Ruxton Graeme D. , Van Der Meer Jaap
Published: March 2003

Unequal competitor ideal free distribution (IFD) models that deal with the effects of interference allow for the relaxation of several unrealistic assumptions of the basic IFD model. We used the recently developed interaction‐matrix method to examine the general case where the effect of interference can vary between patches, one previously unexplored in the literature.

An analytical approach revealed that mixed solutions are not possible for the case of differential interference between patches. However, simulations from an individual‐based model suggest that, when numbers of individuals similar to those commonly used in empirical tests of the IFD are considered, mixed solutions are in fact predicted.

This discrepancy can only be detected by the use of individual‐based models, and may help to explain the lack of certain previously predicted distributions in empirical tests of the theory. We suggest that future work should employ individual‐based models to better link empirical tests with analytic theory.
Influence of metal roughness on the near‐field generated by an aperture/apertureless probe
Authors: Martin O. J. F. , Paulus M.
Published: March 2003

We study the influence of metal roughness on the near‐field distribution generated by an aperture or an apertureless (scattering) probe. Different experimental parameters are investigated: roughness magnitude, aperture form, distribution of the roughness. Our results show that aluminium roughness has a dramatic impact on the emission characteristics of a near‐field probe and in particular on its polarization sensitivity. Apertureless or scattering probes appear to be less sensitive to roughness and to provide a well confined field even with a somewhat rough probe.
Functional characterization of a novel serotonin receptor (5‐HTap2) expressed in the CNS of Aplysia californica
Authors: Barbas Demian , Zappulla Jacques P. , Angers Stéphane , Bouvier Michel , Castellucci Vincent F. , DesGroseillers Luc
Published: March 2003

Serotonin has been shown to be a neuromodulator in the Aplysia californica CNS. The diversity of serotonin actions is due to the existence of several different receptor subtypes. In this study we report the cloning of a full‐length cDNA, coding for a novel serotonin receptor (5‐HTap2). The receptor protein bears the characteristics of G protein‐coupled receptors. It shares 68% and 34% of its amino acid sequence identity with the 5‐HTlym receptor from Lymnaea stagnalis and the mammalian 5‐HT1A receptor, respectively. When transfected in HEK 293 cells, 5‐HTap2 was negatively coupled to adenylate cyclase. Ligand binding analysis indicated that the order of potencies of various drugs for the inhibition of [3H]LSD binding was: methiothepin >
metergoline
> 5‐CT > PAPP > 5‐HT >
ketanserin
> NAN‐190 > 8‐OH‐DPAT > clozapine. RT‐PCR amplification of RNA isolated from different tissues indicated that this receptor is expressed in the CNS and in bag cells. The expression of 5‐HTap2 restricted to the CNS suggests an important role for this receptor in the modulation of neuronal functions in Aplysia. Moreover, the high expression of 5‐HTap2 in the bag cells, associated with its pharmacological profile, suggests that this receptor may be implicated in modulating the afterdischarge during the egg‐laying behavior.
Reduced nitric oxide metabolites in CSF of patients with tetrahydrobiopterin deficiency
Authors: Zorzi Giovanna , Thöny Beat , Blau Nenad
Published: March 2003

We investigated CSF concentrations of nitrite and nitrate as indicators of nitric oxide (NO) production in patients with tetrahydrobiopterin (BH4) deficiencies. Patients with 6‐pyruvoyl‐tetra‐hydropterin synthase, sepiapterin reductase and dihydropteridine reductase deficiencies exhibited decreased CSF nitrite + nitrate levels compared with healthy control subjects. Reduced levels of nitrite + nitrate were not influenced by oral administration of 2.5–5.0 mg/kg tetrahydrobiopterin. Our data indicate impaired NO synthase function in patients with BH4 deficiency and suggest possible involvement in the neuronal cell dysfunction.