bluuebunny/crossref_metadata_2025 huggingface dataset:
Quality of cold and warm gutta‐percha fillings in oval canals in mandibular premolars
Authors: Wu M‐K. , Kašt'áková A. , Wesselink P. R.
Published: March 2003

Aim

The aim of this study was to determine the quality of cold and warm gutta‐percha fillings in oval canals.

Methodology

Two groups of mandibular premolars with oval canals were selected after bucco‐lingual and mesio‐distal radiographs indicated an internal long : short diameter of ≥1.6 at a level 5 mm from the apex. After instrumentation they were obturated, respectively, by cold lateral compaction of gutta‐percha cones (cold GP) and vertical compaction of warm gutta‐percha (warm GP). Leakage along apical root fillings was measured using a fluid transport model. After the leakage test, horizontal sections were cut 2 and 4 mm from the apex. The area of the canal and gutta‐percha in cross‐sections was measured using an image analysis program. The quality of root fillings was evaluated by calculating the percentage of gutta‐percha‐filled canal area (PGP).

Results

No significant difference in leakage was found between the two groups (P = 0.570). The warm GP group produced significantly higher PGPs than the cold GP group 4 mm from the apex only (P = 0.522 at 2 mm; P = 0.000 at 4 mm).

Conclusions

The percentage of gutta‐percha‐filled canal area using warm GP was greater than that of the cold GP in oval canals.
Guided bone regeneration (GBR) using membranes and calcium sulphate after apicectomy: a comparative histomorphometrical study
Authors: Yoshikawa G. , Murashima Y. , Wadachi R. , Sawada N. , Suda H.
Published: March 2003

Aim The purpose of the present study was to evaluate the effects of resorbable and non‐resorbable membranes, and calcium sulphate on bone regeneration in osseous defects in conjunction with apicectomy.

Methodology The mandibular third and fourth premolars of 12 beagle dogs were root treated, and apicectomies were performed. The osseous defects were divided randomly into five groups. In groups A, B and C the osseous defects were covered with e‐PTFE membranes, PLGA membranes, and collagen membranes, respectively. In group D, defects were filled with calcium sulphate. Nothing was used in group E, which served as controls. The dogs were sacrificed 4, 8, and 16 weeks after the surgery. Undemineralized sections were obtained and evaluated histomorphometrically.

Results Newly formed cortical bone had closed the defect in the cortical plate in all groups at 16 weeks. The degree of concavity of the new cortical bone at 16 weeks in groups A and D was significantly less than in group B (P < 0.01). The percentage of regenerated bone in group A was significantly greater than in groups B (P < 0.01), C (P < 0.05) and E (P < 0.05). In group D, it was significantly greater than in groups B (P < 0.01) and E (P < 0.05).

Conclusions The data suggests that e‐PTFE membrane is more effective compared to resorbable membranes and controls for bone regeneration after apicectomy, and that calcium sulphate could be substituted for e‐PTFE membrane.
Effects of rotary instruments and ultrasonic irrigation on debris and smear layer scores: a scanning electron microscopic study
Authors: Mayer B. E. , Peters O. A. , Barbakow F.
Published: March 2003

Aim This study evaluated debris and smear layer scores after two types of instruments manufactured from different alloys were used to ultrasonically activate irrigants during canal preparation. The influence of two rotary preparation techniques on cleanliness of the shaped canals was also studied.

Methodology Apical stops were prepared to size 45 in 42 single‐canalled extracted premolars and canines, which were divided into six equal groups. Groups 1, 2 and 3 were prepared by ProFile .04 (PF) while groups 4, 5 and 6 were prepared by Lightspeed (LS). All groups were irrigated using 5.25% NaOCl and 17% EDTA. Irrigants in groups 2 and 5 were ultrasonically activated using a size 15 steel K‐file and by a blunt flexible nickel–titanium wire in groups 3 and 6. Groups 1 and 4 served as negative controls. Roots were split and canal walls examined at 15×, 200× and 400× magnification in an SEM. Smear layer and debris scores were recorded at 3, 6 and 9 mm levels using a 5‐step scoring scale and a 200‐µm grid. Means were tested for significance using nonparametric Mann–Whitney U and Kruskal–Wallis tests.

Results Debris and smear layer scores for the six groups varied from 1.98 ± 1.04 to 3.47 ± 0.97 and from 1.37 ± 0.4 to 2.36 ± 0.99, respectively. Although all groups had significantly higher smear layer and debris scores at the 3 mm levels compared to the 9 mm levels (P < 0.05), no significant differences were recorded due to the ultrasonic energy transmitted by the two alloys.

Conclusion Ultrasonically activated irrigants did not reduce debris or smear layer scores. This finding was not influenced by the material nor by the design of the instrument used to transmit ultrasonic activation.
Semen levels of mitochondrial DNA deletions in men attending an infertility clinic do not correlate with phenotype
Authors: CUMMINS  , JEQUIER  , MARTIN  , MEHMET  , GOLDBLATT
Published: March 2003

In view of previous reports associating mitochondrial DNA deletions with male reproductive disorders, levels of the `common' 4977 bp mitochondrial DNA deletion were evaluated semi‐quantitatively in 64 men, without prior knowledge of the clinical diagnosis. Significant levels of deletions were detected in 34/64 men (53%) but 29 of these (45%) had a normal semen profile and were phenotypically normal. No deletions were detected in 30 men, of whom 21 were normospermic, six were oligozoospermic and three were azoospermic. It is concluded that although mitochondrial DNA deletions within the testis may be associated with primary testicular disease, no correlation with semen quality was evident in this study, thus limiting its potential use as a diagnostic test.
Freezing of testicular tissue as a minced suspension preserves sperm quality better than whole‐biopsy freezing when glycerol is used as cryoprotectant
Authors: CRABBÉ  , VERHEYEN  , TOURNAYE  , STEIRTEGHEM A. VAN
Published: March 2003

Frozen–thawed testicular spermatozoa have been used successfully for ICSI, especially in cases of obstructive azoospermia with normal spermatogenesis. Fewer attempts, however, have been made to check whether these rather immature spermatozoa, in a different environment with several other cell types present, have cryobiological requirements other than those of ejaculated spermatozoa. This is the reason why the freezing protocols and cryoprotectants (glycerol) used for freezing testicular tissue are based on experience with semen freezing. This study aimed to assess whether cryosurvival and/or motility was influenced by freezing of testicular tissue either as an intact biopsy or as a shredded tissue suspension, when glycerol was used as cryoprotectant. Freezing of testicular tissue as a suspension preserved motility (type B + C) significantly better than freezing of whole biopsies (9.2% vs. 4.0%). Similar observations have been made for vitality (39.3% vs. 25.4%). Centrifugation on 50% Percoll in order to remove the cryoprotectant resulted in a huge loss of spermatozoa (or late spermatids) and should therefore be especially avoided in cases of testicular failure. On the basis of these observations, mincing of the testicular biopsies before freezing may be advocated. Testicular spermatozoa seem to be better preserved when frozen in suspension, at least when slowly permeating glycerol is used as a cryoprotectant.
Sources of oestrogen in the testis and reproductive tract of the male
Authors: Carreau  , Genissel  , Bilinska  , Levallet
Published: March 2003

The cytochrome P450 aromatase (P450arom) is the terminal enzyme responsible for the irreversible transformation of androgens into oestrogens and is present in the endoplasmic reticulum of various tissues throughout at least the phylum of vertebrates. The CYP 19 gene is unique and its expression is regulated in a tissue and more precisely in a cell‐specific fashion via the alternative use of several promoters located in the first exons. The P450arom has been immunolocalized in germ cells of the mouse, brown bear and rooster. According to age, aromatase activity has been measured in immature and mature rat Leydig cells as well as in Sertoli cells, whereas in the pig, ram and human aromatase is mainly present in Leydig cells. In the adult rat testis, four complementary approaches (RTPCR, in situ hybridization, immunocytochemistry and the tritiated water assay) demonstrate that not only somatic cells but also mature germ cells represent a source of oestrogen synthesis. Taking into account the widespread distribution of oestrogen receptors (ERα & ERβ) in testicular cells and the genital tract of the male on the one hand, and the cross‐talk between sex steroids and growth factors, and between membrane receptors and nuclear receptors for steroids on the other hand, it is anticipated that understanding of the pathophysiological roles of these ‘female’ hormones in the male will advance understanding of the hormonal regulation of male reproductive function. One of the future goals is to define oestrogen‐targeted genes in the male gonad and indeed, a lot of work is now focused on this specific area in order to clarify the role of oestrogens in the reproductive tract of the male as well as to elucidate the regulation of aromatase gene expression.
Reactive oxygen species (ROS) production and the outcome of diagnostic tests of sperm function
Authors: Whittington Kate , Harrison Shona C. , Williams Kate M. , Day Joanne L. , Mclaughlin Eileen A. , Hull Michael G. R. , Ford W. Christopher L.
Published: March 2003

Washed sperm suspensions from 64 out of 89 (72%) randomly selected infertility patients produced detectable reactive oxygen species (ROS) compared to 17 out of 67 (25%) prospective semen donors (p < 0.01, Chi‐square test). Among patients, the median sperm concentration in ejaculates which yielded sperm suspensions that generated detectable levels of ROS was lower than in those which did not: 36.2 (15.63–57.64) vs. 71.5 (22–108) × 106/mL, respectively (median (interquartile range), p < 0.05, Kruskal–Wallis test). In samples that produced ROS, the basal rate of production and the rates after stimulation with 50 μmol N‐formyl met leu phe (N‐FMLP) l–1 or with 100 nmol phorbol 12‐myristate 13‐acetate (PMA) l–1 were significantly and inversely correlated with sperm concentration in the ejaculate (r=–0.43, –0.41 and –0.35, respectively, p < 0.01 Spearman’s rank correlation). The rate of ROS production showed no relationship to the motility of spermatozoa in semen, whether evaluated visually or via computer assisted semen analysis. However, there was a significant negative correlation (r=–0.370) between the motile, normal sperm concentration (MNSC) and basal ROS production, and when stimulated with N‐FMLP (r=–0.311) or with PMA (r=–0.249) (all p < 0.05). In patient samples that generated detectable ROS, the ability of the spermatozoa to retain motility for 24 h after preparation on a 40/80% Percoll gradient was negatively correlated with basal ROS production (r=–0.310, p < 0.05). ROS production was also related to the outcome of in vitro sperm mucus penetration tests. Unstimulated levels of ROS production showed a significant (p < 0.05), negative correlation with the number of progressively motile spermatozoa present in mucus after 15 (r=–0.379) and 60 (r=–0.362) min. These results suggest that sperm samples with increased ROS tend to have poor semen quality and reduced performance in a number of routine, diagnostic sperm function tests.
Difficulties in measuring the effect of testosterone replacement therapy on muscle function in older men
Authors: Clague John E. , Wu Frederick C. W. , Horan Michael A.
Published: March 2003

Muscle wasting in older men may be related to androgen deficiency. We have assessed the effect of testosterone replacement therapy on muscle function in the upper and lower limbs of older (age >60 years) men with blood testosterone levels < 14 nmol/L. Subjects (n = 7 per group) received testosterone enanthate 200 mg i.m. or placebo every 2 weeks in a double blind study over a 12‐week period and underwent muscle testing every 4 weeks. A significant increase in blood levels of testosterone and a reduction in levels of sex hormone binding globulin occurred in the treatment group. Total body mass, haemoglobin and packed cell volume also increased significantly (p < 0.05). No improvements in handgrip strength, isometric strength of knee flexors and extensors or leg extensor power were seen in either group. Wide variability in all measures of muscle function were observed in these elderly men suggesting that very large study groups would be required to determine potential treatment benefits on muscle function.
Enzymatic treatment of spermatozoa with a trypsin solution, SpermSolute: improved motility and enhanced ATP concentration
Authors: Figenschau  , Bertheussen
Published: March 2003

We have developed a solution, fully described in this report, that can be used in a pretreatment procedure to promote liquefaction and to enhance motility during preparation of spermatozoa. It was applied to native ejaculates prior to swim‐up and, in parallel investigations, motility and adenosine triphosphate concentration were compared in treated and untreated samples, which revealed that the solution significantly improved both parameters. The solution, named SpermSolute, is based on a proteinase (trypsin), which previously has been shown to stimulate the activity of a glycolytic key‐enzyme. We speculate that our findings reflect intracellular enzyme activation and we suggest that our formula can be used in sperm preparation to prevent cell aggregates and to promote liquefaction, in addition to promotion of motility.
New therapies for erectile dysfunction
Authors: Tan Hui‐Meng
Published: March 2003

The quest for improving and maintaining sexual function has been going on since time immemorial. The advent of an effective oral drug, sildenafil, has brought about unprecedented open discussion on male erectile dysfunction, and gas accelerated the pace of development of new therapies for erectile dysfunction. New knowledge in the physiology of sexual function has enabled researchers to target drug treatment at the whole network of the central nervous system and the numerous cascadic enzymatic reactions leading to relaxation of the corporal smooth muscle. One of the brightest potential applications of future molecular technology in the study of erectile dysfuction is in the utilization of gene therapy.
Metabolism of the putative antifertility agents 3–36chloro‐1‐hydroxypropanone and its dimethyl ketal in the male rat
Authors: Cooper  , Jones
Published: March 2003

3–36Chloro‐1‐hydroxypropanone (CHOP), a specific inhibitor of sperm glycolysis in vitro, is rapidly metabolized by the male rat to α‐chlorohydrin, 3‐chlorolactate and the inhibitory sperm metabolite, 3‐chlorolactaldehyde, presumably all being of the (S)‐configuration. The dimethyl ketal of 36Cl‐CHOP (3–36Cl‐dimethyl‐CHOP) is rapidly metabolized producing identical metabolites and excreted radioactivity in urine at a similar rate. As neither compound produced diuresis, glucosuria or induced the formation of spermatocoeles, conditions associated with related male antifertility and antiglycolytic agents, they could represent an alternative means of producing (S)‐3‐chlorolactaldehyde within spermatozoa in vivo.
The motility of demembranated human spermatozoa is inhibited by free calcium ion activities of 500 nmol/L or more
Authors: Williams K. M. , Ford W. C. L.
Published: March 2003

A number of studies have demonstrated that high calcium ion activities inhibit sperm motility, but little is known about the effect of different calcium activities close to the physiological range. Therefore, we investigated whether raising calcium activities within the submicromolar range would inhibit the motility of demembranated human spermatozoa. Spermatozoa were demembranated with Triton X‐100 and motility was measured objectively by computer assisted semen analysis. Motility, reactivated by 1 mol adenosine 5′‐triphosphate (ΑΤP)/L, was short lived, with maximum activity only sustained for about 1 min. Reactivated motility was not affected by 50 μmol cAMP/L. The amplitude of lateral head displacement was significantly greater at room temperature than at 37 °C, but there were no significant differences between the percentage of sperm motile or their velocity at the two temperatures. The calcium buffer 1,2‐bis(2‐aminophenoxy)ethane‐N,N,N′,N′‐tetraacetic acid (BAPTA) at 1 mmol/L was included in the demembranation–reactivation medium, and free calcium ion activities were calibrated using the fluorescent calcium probe Fura‐2. Calcium ion activities of ≥500 nmol/L significantly inhibited the percentage of demembranated–reactivated spermatozoa that were motile, and the velocity and lateral head displacement of these cells. The range of intracellular calcium activities in spermatozoa from 24 cryopreserved ejaculates was 110–534 nmol/L; roughly twice the value in fresh spermatozoa. Therefore, calcium ion activities in the range observed in cryopreserved spermatozoa can inhibit the activity of demembranated human spermatozoa.
Detection of progesterone receptors in human spermatozoa and their correlation with morphological and functional properties
Authors: Contreras H. R. , Llanos M. N.
Published: March 2003

In previous reports, it has been demonstrated that progesterone (P) stimulates capacitation, hyperactivation of human sperm motility and initiates the acrosome reaction (AR). This last effect has been related to the presence of non‐genomic receptors for the steroid, localized on the sperm head plasma membrane. These receptors can be detected after treating spermatozoa with the non‐permeable conjugate Progesterone – 3‐(O‐carboxymethyl) oxime: bovine serum albumin‐fluorescein isothiocyanate (P‐BSA‐FITC). In the present study, the presence of progesterone receptors was determined in a selected sperm population with normal morphology and high progressive motility. In addition, other parameters such as the AR, hypo‐osmotic swelling test, stability of chromatin and capacitating effect of P were evaluated. The percentage of P‐BSA‐FITC positive‐spermatozoa present in the selected sperm population was higher than in total seminal spermatozoa. Furthermore, spermatozoa incubated with P showed a higher percentage motility and AR than did control spermatozoa. The HOS test indicated that membrane integrity of P‐treated spermatozoa was not different to that found in the control sperm suspensions. Unexpectedly, the total sperm population treated with P showed a marked susceptibility to nuclear decondensation with reducing agents. According to these results, the selected sperm population of this study, able to respond to P, may be similar to that with good motility and normal morphology selected in the female reproductive tract, before fertilization.
Effect of anticoagulation upon nephron obstruction in experimental acute ischaemic renal failure. A morphological study
Authors: DRUID HENRIK , ENESTRÖM SVERKER , RAMMER LENNART
Published: March 2003

Ischaemic‐reperfusion injury as a model of acute renal failure (ARF) results in increased macromolecular permeability, tubular obstruction, and renal oedema. To investigate the role for coagulation in this model, anticoagulated and saline‐pretreated rats were subjected to 60 min unilateral renal artery occlusion (RAO). After 15 min of reflow, specimens were collected for electron and light microscopic examination. Morphometry was employed to study podocyte changes and Bowman's space dilatation as measures of increased permeability and tubular obstruction, respectively. After 15 min of reflow, Bowman's space increased significantly and the podocytes were markedly widened and flattened. Rats pretreated with heparin or warfarin showed less widening of Bowman's space than saline‐treated rats, whereas no significant difference was seen regarding the podocyte changes. In saline‐treated rats, fibrin‐positive material was seen in the tubules but not in the urine sediments collected after 90 min of reflow, either due to fibrinolysis or poor urinary elimination. The results suggest that anticoagulation does not preclude the glomerular sieving of macromolecules, but seems to reduce tubular obstruction, probably by preventing conversion of filtered fibrinogen into fibrin.
Regional activation of the immediate‐early response gene c‐fos in infarcted rat hearts
Authors: LARSEN TERJE H. , SKAR ROBERT , FROTJOLD EDEL K. , HAUKANES KJELLFRID , GREVE GOTTFRIED , SÆTERSDAL THORVALD
Published: March 2003

Regional infarction of the left ventricle is followed by hypertrophy of the viable myocardium. This compensatory growth of cardiac myocytes requires induction of gene transcription and synthesis of proteins. In this study, we examined the expression of the immediate‐early response gene c‐fos following ligation of the left coronary artery in rat hearts. RNase protection assay demonstrated a rapid increase in the c‐fos mRNA level in the ventricular myocardium. After two days of infarction, the c‐fos expression was attenuated and was comparable to that observed in sham‐operated control hearts. In situ tissue distribution of Fos protein‐like immunoreactivity revealed the appearance of positively stained cells adjacent to the lateral border of the ischaemic myocardium, in the left ventricular subendocardial areas, in the papillary muscles of the left ventricle, in the proximity of great transmural vessels, and focally in the normo‐perfused subepicardial myocardium. Double staining using antibodies recognizing the Fos protein and α‐actinin, confirmed that the accumulation of nuclear Fos protein‐like immunoreactivity was mainly seen in the cardiac myocytes. However, double staining of the Fos protein and Hoechst DNA labelling showed that detectable immunoreactivity occurred only in a limited proportion of the total nuclei present in these myocardial regions. Moreover, the regions showing c‐fos activation correspond to the areas in which the appearance of subsequent growth responses are most pronounced following myocardial infarction. The present results therefore indicate that an early and regional c‐fos activation is taking place in viable cardiac myocytes following left coronary artery ligation, and that c‐fos is a possible regulating factor of sequential events leading to altered pattern of gene expression and protein synthesis in the hypertrophying heart.
Decreased prostaglandin E2 synthesis by lung fibroblasts isolated from rats with bleomycin‐induced lung fibrosis
Authors: OGUSHI FUMITAKA , ENDO TAKESHI , TANI KENJI , ASADA KANJI , KAWANO TETSUYA , TADA HIROYA , MANIWA KOJI , SONE SABURO
Published: March 2003

In order to clarify the mechanism of pulmonary fibrosis, we examined the functional changes of lung fibroblasts in bleomycin (BLM)‐induced pulmonary fibrosis. Lung fibroblastic cells were obtained from rat lungs after an intratracheal treatment of BLM or saline. The spontaneous proliferation of BLM‐treated rat fibroblasts (BRF), which was estimated by 3H‐TdR incorporation and direct cell counting, was significantly more rapid than that of normal saline‐treated rat fibroblasts (NRF). Next, we investigated prostaglandin (PG) E2 synthesis by BRF and NRF, with or without stimulation by interleukin (IL)‐1α, and found that PGE2 production by BRF was significantly less than that by NRF. There was no significant difference in cyclooxygenase (COX) activity and COX‐2 mRNA level between BRF and NRF, indicating that the change in PGE2 production was independent of COX, a rate‐limiting enzyme for the production of PGE2. These results suggest that the proliferation of fibroblasts is down‐regulated by PGE2 released from themselves in normal lungs in an autocrine fashion, thus the decreased PGE2 production observed in lung fibroblasts from rats with BLM‐induced pulmonary fibrosis may result in the excessive fibroblast proliferation in this disorder. Overall, these findings throw some light on the mechanism of development of BLM‐induced pulmonary fibrosis.
Profile of transforming growth factor‐beta 1 in patients with dengue haemorrhagic fever
Authors: Agarwal  , Elbishbishi  , Chaturvedi  , Nagar  , Mustafa
Published: March 2003

The pathogenesis of dengue haemorrhagic fever (DHF) is incompletely understood but it has been suggested that various cytokines may have a role in the process. In this study the profile of the cytokine Transforming Growth Factor‐beta 1 (TGF‐β1) was investigated in the sera of 79 patients with various grades of dengue illness and in 21 normal healthy controls. Also, TGF‐β1‐specific mRNA was examined in their peripheral blood mononuclear cells (PBMC). The results showed that neither TGF‐β1 protein nor its mRNA were detected in healthy controls. In dengue patients, the TGF‐β1 protein and its mRNA were detected in 96%. However, among the patient groups, the levels of TGF‐β1 were lowest in patients with dengue fever (DF; mean value 315 ± 95 pg/ml) and were highest in patients with DHF grade IV (mean value 1350 ± 280 pg/ml; P = < 0.001). The cytokine appeared during the first four days of illness (304 ± 90 pg/ml) and gradually increased, reaching peak levels (1050 ± 215 pg/ml) after the 9th day of the illness. Thus TGF‐β1 in the sera and TGF‐β1‐mRNA in the PBMC were present in most of the patients with dengue (96%) but the cytokine levels were highest during the later periods of illness and in patients with DHF grade IV, suggesting a possible role of TGF‐β1 in the pathogenesis of DHF.
Acinar cell apoptosis and the origin of tubular complexes in caerulein‐induced pancreatitis
Authors: Reid Lynne E. , Walker Neal I.
Published: March 2003

The interrelationship between acinar cell apoptosis and tubular complex formation was examined in caerulein‐induced pancreatitis using histology, immunohistochemistry, electron microscopy and DNA gel electrophoresis. Rats were given 8 hourly subcutaneous injections of caerulein, 24μg/kg, for up to 2 days. Morphologically and biochemically typical apoptosis affected 4.6 and 8.9% of acinar cells at 1 and 2 days, respectively, resulting in removal of most acinar cells by 2 days. Consequently, pancreatic ducts, the lining cells expressing bcl‐2 and therefore resistant to apoptosis, became much more closely approximated to form the basis of tubular complexes; small numbers of immunohistochemically discrete acinar cells in their lining were either pre‐apoptotic resistant to it or newly formed. Proliferation of duct‐like lining cells was associated with apoptosis, an increase in islet cells and acinar cell regeneration. There was evidence of duct to acinar cell differentiation but the main increase in acinar cell numbers appeared to derive from proliferation of newly formed acinar cells.
Antioxidant status in delayed healing type of wounds
Authors: Rasik Anamika M. , Shukla Arti
Published: March 2003

This investigation studied the contribution of antioxidants in delaying healing in excision cutaneous wounds (8 mm) in diabetic, aged and immunocompromised animals. Skin levels of catalase, glutathione (GSH), ascorbic acid (AA) and vitamin E in streptozotocin‐induced diabetic rat were lower as compared to nondiabetics. The 7‐d wound tissue of diabetic rats showed an increased vitamin E level along with depleted GSH content. In aged rats (18 months old), higher levels of skin superoxide dismutase (SOD), glutathione peroxidase (Gpx) and thiobarbituric acid reactive substances (TBARS) and lower levels of catalase and GSH were found as compared to their values in young rats (3–4 months old). The levels of SOD, GPx, catalase, AA, GSH and vitamin E in 7‐d wound tissue of aged rats were significantly lower in comparison to those in young rats. However, TBARS were elevated in these wound tissues. The non‐wounded skin of immunocompromised (athymic) mice showed lower levels of SOD, catalase, and TBARS and higher GSH and GPx levels in comparison to those present in normal mouse skin. Surprisingly, the analysis of 7‐d wound tissue showed higher levels of SOD, catalase, GPx, and GSH and lower TBARS level in athymic mice compared to the wound tissue of normal mice.

Thus low levels of antioxidants accompanied by raised levels of markers of free radical damage play a significant role in delaying wound healing in aged rats. In diabetic rats reduced glutathione levels may have a contributory role in delaying the healing process. However, in immunocompromised mice the antioxidant status following injury showed an adapted response.
Microbiology of food taints
Authors: Whitfield Frank B.
Published: March 2003

Fresh and processed foods are often spoilt by the presence of undesirable flavours and odours caused by microbial action. The aim of this paper is to review the current knowledge of microbiologically induced taints that occur in a wide range of foodstuffs, including meats, poultry, fish, crustaceans, milk, dairy products, fruits, vegetables, cereals and cereal products. Examples have been chosen where the compounds responsible for the taint have been identified and sufficient data obtained to demonstrate the involvement of microorganisms. However, in some cases the full identity of the causative organism may not have been elucidated. The types of microorganisms covered by this review include bacteria, fungi, yeasts, actinomycetes and cyanobacteria. Although cyanobacteria do not in general infect foods, their presence in aqueous systems and water supplies can lead to off‐flavours in aquatic organisms and processed foodstuffs. Several examples of each of these processes are discussed. Wherever possible, the likely biosynthetic pathway used by the microorganism to produce the offending compound in a foodstuff is indicated.
Dielectric analysis of hen egg white with denaturation and in cool storage
Authors: Lu Yongjun , Fujii Mamiko
Published: March 2003

Dielectric relaxation spectra (DRS) of fresh hen raw egg white solutions and thermally denatured gels were measured at frequencies between 1 MHz and 3 GHz by using the coaxial line reflection method with a network analyser and an open‐ended coaxial probe. The values of the dielectric constant ε of the denatured gels were higher than those of the raw solutions at frequencies lower than 100 MHz and then became close to each other with the increase in the frequency. No significant change in effective conductivity σ was found on denaturation, implying that this process does not affect the binding of water. The gels were stored at 5°C for 13 days to be subjected to a dehydration process that led to a corresponding decrease in dielectric constant and conductivity. When the dielectric data had been measured, the molecular motions and water status in the egg whites were analysed.
The effect of freezing and thawing on the magnetic resonance imaging parameters of water in beef, lamb and pork meat
Authors: Evans Stephen D. , Nott Kevin. P. , Kshirsagar Ashwini A. , Hall Laurance D.
Published: March 2003

A new multisample magnetic resonance imaging (MRI) technique has been used to measure the values of T1, T2, magnetization transfer (MT) rate and liquid proton density ratio (M0%) for water in fresh and frozen–thawed beef, lamb and pork; four samples from the longissimus dorsi muscle of 25 different individuals per species were studied. The effect of two different chilling regimes, standard and tenderloin, were also studied. Standard chilled pork and lamb had a significantly higher M0% than tenderloin chilled samples, but there was no correlation between M0% and fresh weight; the differences in M0% are thought to be due to differences in MR (magnetic resonance)‐visible water. There was a significant decrease in water content, T1 relaxation time, and a significant increase in MT rate in the frozen–thawed samples when all the data were pooled for each species. However, individual animals differed in the magnitude and direction of the change; this means that because of interanimal variation, measurements of MR parameters from a single sample of meat cannot be used at present to authenticate it.
Control of microbial growth on rice sprouts
Authors: Piernas Valérie , Piernas Valérie , Guiraud Joseph P. , Guiraud Joseph P.
Published: March 2003

Different methods were investigated to prevent microbial hazards during rice sprouting. Disinfection of rice seeds before germination resulted in an immediate but temporary fall in microbial counts, except for minor populations (e.g. coliforms growing at 44 °C), which were totally eliminated. The levels were otherwise back to those of unsanitized seeds 24 h later. In‐process sprays of chlorinated water failed to limit the growth of residual bacteria. Post‐harvest decontamination was considered to improve the microbiological quality of sprouts. Experiments with artificially inoculated seeds demonstrated that immersing sprouts for 5 min in 60 °C water could decrease potential Listeria contamination to a safe level but that immersion would have no effect on the numbers of Bacillus cereus unless the temperature was increased to 100 °C.
Effects of the indigenous microflora of minimally processed lettuce on the survival and growth of Listeria innocua
Authors: Francis Gillian A. , O'Beirne David
Published: March 2003

Interactions between the natural background microflora of shredded lettuce and Listeria innocua (in lieu of Listeria monocytogenes) were studied. The effect of increasing the initial size of indigenous populations (from 103 to 106–107 CFU g−1) was tested for its ability to reduce L. innocua growth on shredded lettuce. Co‐culture experiments were performed in model media, where bacterial isolates from the indigenous microflora were tested for possible inhibitory effects. Varying the size of the indigenous populations had no effect on L. innocua survival or growth. However, interactions with individual species and mixed populations from lettuce did affect the survival and growth of L. innocua in model media. In general, mixed populations diminished L. innocua growth. In the undiluted lettuce medium, the various species tested individually either reduced or did not affect the growth of L. innocua. However, when the medium was diluted, some species extended the survival of L. innocua. Competition between the indigenous microflora and L. innocua resided mostly with the Enterobacter spp. and not with the pseudomonads. Enterobacter cloacae was particularly effective in reducing L. innocua growth. Lactic acid bacteria also reduced L. innocua growth in undiluted media. It is concluded that interactions with the natural background microflora may play an important role in determining the dynamics of Listeria populations on shredded lettuce.
Antibiotic use in aquaculture: development of antibiotic resistance – potential for consumer health risks*
Authors: Alderman D. J. , Hastings T. S.
Published: March 2003

As aquaculture has developed, a range of bacterial diseases have been encountered that have caused both major production problems and animal welfare difficulties. These diseases were initially controlled almost exclusively by the use of antimicrobial agents. Fish farming is now a sufficiently large and mature an industry to have justified the development of an effective range of vaccines that have largely supplanted the use of antimicrobial agents for most bacterial diseases in salmonid farming in Europe and North America. For most salmonid bacterial diseases, use of antimicrobial agents is now largely confined to emergency use in the event of breakdown of vaccine protection. In addition to the increasing availability of vaccines, aquaculture is steadily developing a range of improved husbandry methods to reduce the impact of disease. Although there is evidence that antibiotic resistance can be selected for in normal therapeutic use in aquaculture, the risks of transfer of such resistance to human consumers by any of the possible routes appears to be low. Where new species are under development for aquaculture and during the development of these species, bacterial diseases may be expected to occur that will need use of antimicrobials for disease control before vaccines can be developed. If antimicrobials were not available for use with new species, development would be likely to transfer to countries with poorer controls on antibiotic use. Use of antimicrobial agents in ornamental fish, particularly in some exporting countries, is significant, and evidence exists that multiple antibiotic resistant bacteria may be frequent in such animals. Although ornamental fish are not eaten, they do enter homes and are in close contact with humans.
Aquaculture production and potential for food safety hazards in sub‐Saharan Africa: with special reference to Malwai*
Authors: Chimatiro S. K.
Published: March 2003

Aquaculture in Africa accounts for less than 2% of total domestic fish production. Although its contribution has expanded significantly from 59 000 Mt in 1985 to 85 000 Mt in 1990, the estimated potential is 3.5 million Mt per year. Of the 20 major species cultured, only Nile tilapia, African catfish and common carp are farmed throughout Africa. The leading fish culture producers, Cote d'Ivoire, Egypt, Kenya, Nigeria, South Africa, Tunisia and Zambia, accounted for more than 95% of production in 1990. Production has remained static in many countries (e.g. Cameroon, Ghana and Nigeria) and has decreased in others (e.g. Madagascar, Uganda). The potential for aquaculture in the Southern African Development Community (SADC) region is 250 000 t year−1 (present production is 5000 t year−1). Extensive, small‐scale fish farming has expanded in Malawi, Mozambique, Tanzania and Zimbabwe, where there are some 25 000 fish ponds. Fish farming has virtually ceased in Angola and is negligible in other SADC countries. In South Africa, production increased 663% between 1982 and 1992, the fastest growth in the world. Aquaculture development in South Africa has been market driven, dominated by large‐scale producers and no small‐scale operators. Potential health hazards from aquaculture products arise from either contaminants that find their way into the fish during the process of farming (feed additives, drugs) or loss of quality due to poor handling and processing. Poor handling is the greatest potential food safety issue in sub‐Saharan Africa, because much of aquaculture production is undertaken by small‐scale farmers who grow and handle relatively small quantities. About 90% of the fish from capture fisheries in Africa is preserved by means of smoking or roasting (40%) and sun drying (50%). However, the bulk of fish from small‐scale rural aquaculture is sold fresh, whole and ungutted at the pond site. Although the FAO Code of Conduct for Responsible Fisheries and the FAO/WHO Codex Alimentarius Commission make provisions for regulating standards, there are no functional mechanisms to monitor and enforce standards in many countries in sub‐Saharan Africa (probably with the exception of South Africa). There is a need to define ‘reasonable’ critical control points that can easily be achieved by many aquaculture operators in the region. Information flow from produces to consumers and documentation of food safety hazards must also be established, and functional at national and regional level.
Quality of canned mushrooms acidified with glucono‐δ‐lactone
Authors: Rodrigo Mîguel , Calvo Carlos , Sanchez Tomás , Rodrigo Carmen , Martínez Antonio
Published: March 2003

Summary The effect of sterilisation conditions (116 °C, 54 min; 121 °C, 24 min and 126 °C, 8 min) and acidification with glucono‐δ‐lactone as compared with other acids (citric, ascorbic and EDTA) on the yield and quality (colour, texture and taste) of canned whole mushrooms, has been studied using previously refrigerated raw material (1.5 or 2.5 days at 2 °C). Colour measurement of canned mushrooms by the determination of the L* parameter of ten mushroom pilei probed to be the most suitable method, among those studied, shown the greater F parameter in a variance analysis. Yield was higher when the raw material was stored under refrigeration for longer. Yield, texture and colour improved with the Highest Temperature and Shortest Time process (126 °C, 8 min). Glucono‐δ‐lactone appears to be a more suitable acidulant than citric acid as it provides equal colour, texture and yield without conferring as acid a taste as citric or an extraneous flavour.
The microbiological safety of minimally processed vegetables
Authors: Francis Gillian A. , Thomas Christopher , O'beirne David
Published: March 2003

SummaryDemand for fresh, convenient, minimally processed vegetables has led to an increase in the quantity and variety of products available to the consumer. Modified atmosphere packaging, in combination with refrigeration, is increasingly being employed as a mild preservation technique to ensure quality and storage‐life. The fresh nature of these products, together with the mild processing techniques and subsequent storage conditions, have presented indigenous and pathogenic microorganisms with new ecosystems and potential infection vehicles; a number of outbreaks of foodborne disease being attributed to their consumption. Psychrotrophic pathogens and pathogens which are capable of maintaining an infectious potential under mild preservation regimes are of particular concern;Listeria monocytogenes,Aeromonas hydrophila and Clostridium botulinumbeing amongst the most notable. This review describes the processing, packaging and storage procedures involved in the production of minimally processed vegetables, and details their impact upon the survival and growth of associated pathogens. Gaps in our current understanding of the consequences of this novel technology for microbiological safety are highlighted.
Wetting behaviour of instantized cocoa beverage powders
Authors: Kyaw Hla P. , Hogekamp S.
Published: March 2003

Summary The aim of this work was the characterization of various instantized cocoa beverage powders with regard to their wetting behaviour in a standardized test. Brand name powders from local superstores were compared to each other and to model powders instantized in the laboratory by steam jet agglomeration. Basic powder properties such as agglomerate size or fines content in a mixture were varied to study possible effects on the wettability of this product group.
The effects on colour, texture and sensory attributes achieved by washing black tilapia flesh with a banana leaf ash solution
Authors: Mohsin Md , Bakar Jamilah , Selamat Jinap
Published: March 2003

Summary The washing of freshwater fish with clarified solutions of banana leaf ash to remove the muddy odour and flavour is common both in Bangladesh and Indian households. However, no scientific study has been done to evaluate its effectiveness. This study was, therefore, done to show the effect of the washing treatments on the following sensory attributes: odour; flavour; colour and texture. The latter two attributes were also measured by instrumental methods. The experimental animal was black tilapia (Oreochromis mossambicus), which was filleted and each fillet washed by a clarified solution of banana ash (either originally 5 or 7% ash). Controls were fillets washed in ice‐slush only. Those fillets washed in 5% ash for 5 min were the most acceptable for eating, cooked or uncooked. There were highly significant differences (p < 0.01) in the L‐colour values (lightness values) when treated fillets were compared to untreated fillets. However cooking the fillets reduced the difference, making it not significant. Texture was significantly affected by washing and this was retained in cooked fillets, however this was particularly significant using a 7% solution which gave a softer fillet.
The quality assessment of gari produced by using microwave energy
Authors: Oduro Ibok , Clarke Brian
Published: March 2003

Summary A novel technique using microwave energy for roasting and drying or garification of fermented cassava mash is investigated. The quality of gari produced using this method compared favourably with the standards quoted in the literature and with those of commercial gari purchased from a London market, in terms of colour, swelling capacity, moisture, pH and total acidity.
Effect of anions on the denaturation and aggregation of β‐Lactoglobulin as measured by differential scanning microcalorimetry
Authors: McPhail Deborah , Holt Carl
Published: March 2003

Summary Profound differences in the rate of aggregation and denaturation among β‐lactoglobulin samples from different sources can be reduced or even eliminated by dialysis of the samples first against a phosphate buffer. Visual evidence and thermograms indicated a reduced rate of aggregation in a phosphate buffered salt solution compared to the salt solution alone. The same effect was not achieved by another divalent tetrahedral ion, sulphate, nor by imidazole‐buffered NaCl. Replacement of the background electrolyte by Na acetate had no discernible effect on the thermogram in the phosphate buffer. Phosphate is particularly good at buffering the protein solution at neutral pH at elevated temperature so the main effect is to maintain the net protein charge. In the imidazole and unbuffered media, the protein can move towards its isoelectric point and although the protein is more stable, aggregation is faster. It is speculated that there might also be a specific interaction of the phosphate anion with a cation‐rich region of the β‐lactoglobulin surface which could also inhibit aggregation at elevated temperatures.
Effect of monoglycerides and diglycerol‐esters on viscoelasticity of heat‐set whey protein emulsion gels
Authors: Chen Jianshe , Dickinson Eric
Published: March 2003

Summary Effects of small‐molecule surfactants (emulsifiers) on the small‐deformation viscoelastic properties of heat‐set whey protein emulsion gels have been investigated using a controlled stress rheometer. The surfactants used in this investigation were the water‐soluble diglycerol monolaurate (DGML) and diglycerol monooleate (DGMO), and the oil‐soluble glycerol monooleate (GMO). The elastic modulus of the emulsion gel was found to decrease in the presence of a small amount of surfactant, but then to recover at higher surfactant concentrations. The initial reduction in modulus correlates with protein displacement from the oil droplet surface. The recovery of the storage and loss moduli at higher surfactant concentrations of DGML or DGMO may be due to the depletion flocculation of the emulsion prior to heat‐treatment. However, for systems containing high content of GMO in the oil phase, the recovery of the moduli is probably owing mainly to the smaller average particle size. Effects of surface monolayer composition, droplet aggregation and average particle size were discussed. The behaviour obtained here was compared with results for previously investigated whey protein emulsion gel systems containing different emulsifiers.
β‐Lactoglobulin – a three‐dimensional perspective
Authors: Sawyer Lindsay , Kontopidis George , Wu Su‐Ying
Published: March 2003

Summary Bovine β‐lactoglobulin has been the subject of intense study over the past 60 years by, effectively, every available physicochemical technique, of which one of the most powerful is X‐ray crystallography. We present a short review of the X‐ray crystallographic work on milk protein together with an overview of the properties as they are seen from the current state of crystallographic analyses. At the present time, structural analyses do not provide any further insights into the possible function of the protein.