The effects of lipopolysaccharide-induced endogenous hyperthermia and different antipyretic treatment modalities on rat brain

BACKGROUND

In the present study, the effects of fever and hyperthermia, and different anti hyperthermia treatment modalities on the brain by was investigated by using experimental animal model

MATERIALS AND METHODS

Endogenous hyperthermia (41 degrees C) was induced by lipopolysaccharide (LPS) injection, and the signs of probable neuronal damage were evaluated by healthy, necrotic and apoptotic cells, and heat-shock proteins (HSP 27 and HSP 70) in cerebral cortex, cerebellum and hypothalamus. The animals were treated with widely used treatment modalities for high fever in pediatric practice, namely hypothermia, dexamethasone, paracetamol and diclofenac, and their effect on the hyperthermia-induced brain changes were evaluated.

RESULTS

Generalized seizure was observed in fifteen rats of which rectal temperature achieved 41 degrees C (15/36, 41%); five of them died on second day (5/15, 33%). LPS-induced endogenous hyperthermia; (i) caused significant increase of necrotic cells in cerebral cortex and cerebellum and apoptotic cells in all three regions (p < 0.05), (ii) caused significant decrease of healthy cells in cerebral cortex (p < 0.05), and (iii) no significant change of HSP 27 and 70 in all three neuronal locations (p > 0.05). For the treatment modalities applied; (i) paracetamol had an effect of increasing the healthy cell count in cerebral cortex and hypothalamus and decreasing the necrotic cell count in cerebellum and hypothalamus (p < 0.05).

CONCLUSION

The neuronal tissue in different regions of brain can show various degrees of damage in response to endogenous hyperthermia and the applied medications have varying degree of protection (Tab. 3, Fig. 6, Ref. 44).

Removal of the toxic effects of chlormadinon acetate on the development of Drosophila melanogaster via the use of nordihydroguaiaretic acid

In this study, the effects of chlormadinon acetate (CMA) and CMA + nordihydroguaiaretic acid (NDGA) on various developmental stages of Drosophila melanogaster were investigated. Different concentrations of CMA (1.0; 3.0; 5.0 and 10.0 μM/100 mL medium) and CMA + NDGA as the concentrations of CMA (1.0 + 1.0; 3.0 + 3.0; 5.0 + 5.0 and 10.0 + 10.0 μM/100 mL medium) were carried out during the developmental periods of the flies. When F(1) progeny of control and application groups were compared, CMA was found to extend the process of metamorphosis and decrease the total offspring numbers. However, these negative effects were inhibited by NDGA treatment at different concentrations. These results suggest that NDGA could effectively inhibit CMA-induced abnormalities in developmental stages of D. melanogaster. It was found that the difference between the groups was significantly important (p < 0.05).

Orexins Activates Protein Kinase C-Mediated Ca2+ Signaling in Isolated Rat Primary Sensory Neurons

Previous results have suggested that orexins causes a rise of intracellular free calcium ([Ca2+]i) in cultured rat dorsal root ganglion (DRG) neurons, implicating a role in nociception, but the underlying mechanism is unknown. Hence, the aim of the present study was to investigate whether the orexins-mediated signaling involves the PKC pathways in these sensory neurons. Cultured DRG neurons were loaded with 1 μmol Fura-2 AM and [Ca2+]i responses were quantified by the changes in 340/380 ratio using fluorescence imaging system. The orexin-1 receptor antagonist SB-334867-A (1 µM) inhibited the calcium responses to orexin-A and orexin-B (59.1±5.1 % vs. 200 nM orexin-A, n=8, and 67±3.8 % vs. 200 nM orexin-B, n=12, respectively). The PKC inhibitor chelerythrine (10 and 100 µM) significantly decreased the orexin-A (200 nM)-induced [Ca2+]i increase (59.4±4.8 % P<0.01, n=10 and 4.9±1.6 %, P<0.01, n=9) versus response to orexin-A). It was also found that chelerythrine dose-dependently inhibited the [Ca2+]i response to 200 nM orexin-B. In conclusion, our results suggest that orexins activate intracellular calcium signaling in cultured rat sensory neurons through PKC-dependent pathway, which may have important implications for nociceptive modulation and pain.

CORRELATIVE STUDY OF THE COGNITIVE IMPAIRMENT, REGIONAL CEREBRAL BLOOD FLOW, AND ELECTROENCEPHALOGRAM ABNORMALITIES IN CHILDREN WITH DOWN’S SYNDROME

The aim of this study was to investigate possible correlations of the cognitive impairment with abnormalities of regional cerebral blood flow and electroencephalogram in children with (Down's Syndrome) DS. Nine patients with DS were evaluated by single photon emission computed tomography (SPECT) in combination with clinical findings, electroencephalography (EEG), and magnetic resonance imaging (MRI). In cases with IQs below 40, there were one or more findings of abnormal EEG/MRI and brain perfusion SPECT. In 6 cases (66.7%) EEG findings were normal, but 3 (33.3%) had abnormal EEG findings. Perfusion abnormalities were most pronounced in the fronto-parieto-temporal region in the form of hypoperfusion (n = 5) and in the right hemisphere (n = 5) than the left hemisphere (n = 1). These findings suggest that the children with DS had varying levels of structural, perfusion, and electrophysiological abnormalities in the brain and these abnormalities were reflected by measurable alterations of the cognitive functions.

The trace metal levels in milk and dairy products consumed in middle Anatolia-Turkey

In this study, aluminium (Al), lead (Pb), cadmium (Cd), selenium (Se) and arsenic (As) contents in milk and different dairy product samples were measured. Pb, Cd, As, Al and Se contents in the milk and different dairy products ranged from 0.054 mg/kg (milk powder)-1.100 mg/kg (Kaşar cheese), 0.009 mg/kg (whey powder and yogurt)-0.051 mg/kg (Tulum cheese), 0.010 mg/kg (whey powder)-0.146 mg/kg (butter), 2.848 mg/kg (ice cream)-8.778 (drained yogurt) and n.d. (ice cream, milk and whey powder, yogurt, ayran and Lor cheese)-0.434 mg/kg (Tulum cheese), respectively. The 75% of White and Kaşar cheeses, 50% of Lor and 12.5% of Tulum cheese samples contained higher Pb according to the legal limits established by the Turkish Food Codex and European Communities regulation and 12.5% of Tulum cheese sample contained Cd. It was concluded that Pb contents of milk and dairy products from this region might be highly hazardous to human.

Antinociceptive efficacy of levetiracetam in a mice model for painful diabetic neuropathy

BACKGROUND AND OBJECTIVE

Despite important advances in available knowledge, management of neuropathic pain remains incomplete, and results from experimental and clinical studies indicate that some anticonvulsants show promise for treating neuropathic pain. The aim of this study was to assess the antinociceptive efficacy of levetiracetam (LEV, ucb L059) in a mice model for painful diabetic neuropathy using the in vivo nociceptive behavioral 'hot-plate test.'

METHODS

The hot-plate test consisted of placing individual mice (adult male Balb/C) on the hot plate at 50+/-0.1 degrees C and timing the delay for the first hind paw lift (nociceptive threshold). After obtaining control values, diabetes was induced by injection of streptozotocin [200 mg/kg intraperitoneally (i.p.)] and 2 weeks after induction of diabetes (serum glucose > or =400 mg/dL) LEV was administered i.p. and hot-plate tests were repeated. Pain threshold values were determined and analyzed by Kruskal-Wallis one-way analysis of variance (ANOVA) followed by a pairwise comparison using a Dunnett's t-test on the ranked data.

RESULTS

LEV (60, 300 and 900 mg/kg) had no significant effect on the nociceptive threshold in normal mice (n=8 for each dose, P>0.05). There were significant decreases in pain threshold latency in diabetic mice compared with the normal healthy group and these were significantly and dose-dependently restored by much lower doses of LEV (20, 100 and 200 mg/kg) in a reversible manner.

CONCLUSION

Results obtained from the in vivo behavioral test lend support to the validation of the promising therapeutic potential of the novel antiepileptic agent LEV in the treatment of neuropathic pain.

Children and adolescents with obesity and the metabolic syndrome have high circulating cortisol levels

OBJECTIVES

The aim of this study was to investigate the relationship between the varying degrees of obesity and blood glucocorticoid levels in obese children and adolescents with and without metabolic syndrome features.

METHODS

We studied 241 obese children and adolescents aged between 2 and 17.6 years; 127 boys and 114 girls. All children underwent an oral glucose tolerance test. Measurements included blood pressure, cortisol, ACTH, and lipid profiles. The diagnosis of metabolic syndrome was defined according to the criteria adapted from World Health Organisation and National Cholesterol Education Program Adult Treatment Panel-III guidelines.

RESULTS

Blood cortisol and ACTH levels were higher in patients with MS than without MS (p = 0.02). ACTH levels increased with weight (r = 0.13, p = 0.02), systolic blood pressure (r = 0.21, p = 0.002), diastolic blood pressure (r = 0.17, p = 0.01), fasting glucose (r = 0.17, p = 0.01). Cortisol production was only correlated with systolic blood pressure (r = 0.12, p = 0.05).

CONCLUSIONS

Results from the present study indicates that there may be a link between cortisol production and the metabolic syndrome in obese children and adolescents.

A survey of rate of victimization and attitudes towards physical violence among school-aged children in Turkey

BACKGROUND

Violence of any type is a serious issue in the lives of many children from all racial, cultural and economic backgrounds, and is a topic of enormous societal concern in any society. The purpose of this study was to examine the rate of exposure to violence as victims, and attitudes towards physical violence among school-aged children in eastern Turkey.

METHODS

All the basic education schools in Elazig, a typical eastern Anatolian city, were included. A total of 3725 fifth and sixth graders were asked to answer survey questions about the rate of physical violence exposure in their everyday lives and whether they thought the violence was an 'acceptable' behaviour.

RESULTS

The mean age of participants was 12.8 years with 46.8% boys and 53.2% girls, and their socio-economic status ranged from low-income to upper middle class. Seventy-four per cent of school-aged children reported exposure to at least one case of physical violence in their lives, and 43.4% reported experiencing physical violence within previous 12 months. Higher rates of exposure to physical violence were reported by boys than girls (P = 0.0001). Of the victims, 33.8% regarded physical violence as an acceptable or inevitable way of solution or responding to life events.

CONCLUSIONS

Results from the self-report of the receiving end of violent behaviours indicate that physical violent victimization is at an alarmingly high rate among children of eastern Turkey, and a significant per cent of these victims approves violence as a way of solution.

TOCOLYTIC EFFECT OF PARECOXIB, A NEW PARENTERAL CYCLO-OXYGENASE-2-SPECIFIC INHIBITOR, ON THE SPONTANEOUS AND PROSTAGLANDIN-INDUCED CONTRACTIONS OF RAT ISOLATED MYOMETRIUM

1. The present study was undertaken to elucidate the effects of parecoxib, a novel cyclo-oxygenase (COX)-2 inhibitor, on spontaneous and prostaglandin-induced contractions of uterine smooth muscle. 2. Non-pregnant adult Wistar rats were decapitated and dissected to isolate myometrial strips. The tissue was mounted in 5 mL organ baths filled with Krebs' solution that was maintained at 37 degrees C and bubbled continuously with a mixture of 95% O(2)-5% CO(2) to give pH 7.4. Contractions were recorded through transducers for isometric tension recording. The dose-dependent effects of parecoxib on contractility were quantified by changes in the mean amplitude, frequency and area under the contractile curve (AUC; percentage of control conditions) of the isometric tension recordings, averaged over 5 min intervals. Statistical analyses were performed using ANOVA. 3. Application of parecoxib (50-900 micromol/L) caused dose-dependent decreases in mean amplitude, mean frequency and mean AUC of both spontaneous and prostaglandin-induced contractions. Mean percentage inhibition of the AUC of spontaneous contractions was found to be 29, 56, 74 and 84% in the presence of 50, 150, 300 and 600 micromol/L parecoxib, resepctively (n = 8). In the case of prostaglandin (PG) F(2alpha)-induced contractions, 100, 300, 600 and 900 micromol/L parecoxib resulted in a 27, 43, 61 and 73% inhibition, respectively (n = 9). Moreover, pretreatment with parecoxib (600 micromol/L) reduced the responsiveness and maximum contractility to PGF(2alpha) compared with non-treated strips. 4. The data from the present study indicate, for the first time, that parecoxib inhibits spontaneous and prostaglandin-induced contractions of rat myometrium in vitro. These results raise the possibility that parecoxib may be of therapeutic use in the management of preterm labour and dysmenorrhoea.

Adsorptive removal of Methylene blue and Methyl orange from aqueous media by carboxylated diaminoethane sporopollenin: on the usability of an aminocarboxilic acid functionality-bearing solid-stationary phase in column techniques

The adsorption phenomena of Methylene blue (MB) and Methyl orange (MO) on a carboxylated diaminoethane sporopollenin (CDAE-S) solid phase were investigated in a column arrangement by using breakthrough technique. The adsorption phenomena were evaluated using some common adsorption isotherm models and Scatchard plot analysis, and obtained results were interpreted for evaluating the usability of CDAE-S for removal, recovery and preconcentration of the studied dyes both at the laboratory and industrial scales. On the basis of Scatchard plot analysis, the interaction types between the CDAE-S and the studied dyes were criticized in terms of affinity phenomena. Thus, the usability of a biomacromolecule-derived material, CDAE-S, as a cheap, environmentally-friendly and effective solid-stationary phase exhibiting both cation-exchange and anion-exchange characteristics at the same time, is discussed through the present study. Besides, from the obtained results, the protonated CDAE-S, which functionally resembles an amino acid structure, are presented as a two-in-one solid-stationary phase, and its adaptability to common processes performed under column conditions is also drawn in detail.

Prevalence of domestic violence during pregnancy in a Turkish community

This study was carried out to determine the prevalence and risk factors for domestic violence victimization of women during pregnancy by intimate partner throughout marriage in a Turkish community. Pregnant women living in the servicing area of selected health centers in Elazig were considered for the study and data were obtained through a questionnaire. A total of 249 pregnant women, mean age 26.8 +/- 5.2 years and the mean gravidity 2.6 +/- 1.7, were involved. Of the 249 women, 28.9% were exposed to at least one case of physical violence throughout matrimony, 12.4% being abused during the previous year and 4.8% during the current pregnancy, 30.5% were exposed to verbal insult and 4.4% exposed to sexual abuse during the current pregnancy. In addition, 25.7% were exposed to one or more types of domestic violence during previous pregnancies. There was a significant correlation between the rate of violent victimization and number of children, and the partner's alcohol habits and socioeconomical status of the families (p < 0.05). Results from the self-report of the receiving end of violent behaviors indicate that the rates of any type of intimate partner violence were very high among pregnant women in this studied Turkish population. Efforts to reduce the incidence of this women's rights and public health problem should be given high priority.

The adsorption behavior of crystal violet in functionalized sporopollenin-mediated column arrangements

The adsorption behavior of Crystal Violet (CV) on a sporopollenin-based solid phase, carboxylated diaminoethane sporopollenin (CDAE-S), was investigated under column conditions, and the obtained breakthrough profiles were used in evaluations and quantifications. The adsorption capacity of the CDAE-S was observed to be considerably higher than that of diaminoethane sporopollenin (DAE-S), revealing the importance of electrostatic interactions and carboxyl groups in the adsorption of CV on the CDAE-S. The binding of CV on the DAE-S was found to be a typical nonspecific adsorption, whilst cation-exchange was proposed as the main mechanism for monolayer adsorption of CV on the CDAE-S. Hence in the present study, the cation-exchange is suggested as an effective process for removal and recovery of CV from aqueous effluents, and in view of the pH point of zero charge matter, multifunctionality of the CDAE-S is discussed in detail, and various application possibilities based on "aminocarboxylic acid" functionality are also drawn.

Effect of the temperature and mobile phase composition on the retention behavior of nitroanilines on ligand-exchange stationary phase

This paper deals with the separation of isomers of nitroaniline by liquid chromatography using the ligand-exchange technique. The chromatographic separations were performed on the ligand-exchanger sporopollenin. The sporopollenin used as support of stationary phase was modified with carboxylated-ethylenediamine matrix and was loaded with cobalt(II) ions. Using the column packed with cobalt(II) loaded carboxylated diaminoethyl sporopollenin [Co(II)-CDAE-S], the retention behavior of 3- and 4-nitroanilines was investigated. The mobile phase used, was a mixture of 0.05 M NH(4)OH in ethanol-water. The resolution was strongly affected by the presence of ammonium hydroxide in the mobile phase and a concentration of 0.05 M was shown to be necessary for the separation of analytes. To study the effects of temperature on the resolution, column runs were also performed at various temperatures (15-60 degrees C). With increasing temperature, a decreased interaction between the solutes and the ligand-exchanger was observed. Consequently, the best results were obtained using a mixture of 0.05 M NH(4)OH in ethanol-water (10:90, v/v) as the mobile phase at a column temperature of 35 degrees C. Ligand-exchange chromatography on the Co(II)-CDAE-S could be a useful alternative method for the separation of nitroaniline.

Sildenafil Citrate Inhibits Agonist Induced Contractions in Isolated Rat Seminal Vesicles

PURPOSE

Sildenafil is reported to regulate smooth muscle contractility through nitric oxide-cyclic guanosine monophosphate, not only in the corpus cavernosum. Its possible effects on seminal vesicle contractility might be of importance with respect to premature ejaculation. We investigated the effects of sildenafil citrate (Pfizer, New York, New York) on agonist induced isometric contractions of the rat seminal vesicle in vitro.

MATERIALS AND METHODS

Seminal vesicles isolated from adult male Wistar rats were suspended in an organ bath and contracted by NE (10 microM), ACh (10 microM) or KCl (60 mM) (Sigma, Deisenhofen, Germany). The effects of sildenafil citrate (100 to 300 microM) were evaluated in terms of mean contraction amplitude, the area under force-time curves and isometric contractility indexes.

RESULTS

Sildenafil citrate (300 microM) significantly inhibited the mean amplitude +/- SEM of contractile responses induced by NE (1,061 +/- 153 vs 271 +/- 65 mg, p <0.0001), ACh (475 +/- 51 vs 68 +/- 17 mg, p <0.0001) and KCl (546 +/- 71 vs 59 +/- 18 mg, p <0.0002). It also caused dose dependent concomitant decreases in the area under force-time curves. Additionally, pretreatment with sildenafil citrate markedly prevented the contractile response to NE, ACh and KCl.

CONCLUSIONS

Our results indicate that sildenafil citrate inhibits the contractions of isolated rat seminal vesicle that are induced by NE, ACh or KCl. Future studies may support an in vivo effect of sildenafil for delaying or inhibiting seminal vesicle emission, thereby, promoting improvement in patients with premature ejaculation.

Patients with multiple sclerosis have higher levels of serum ghrelin

In addition to metabolic and neuroendocrine actions, the recently discovered hormone ghrelin has been found to have inhibitory effects on inflammatory processes. This novel finding suggests possible involvement of the peptide in the pathogenesis of inflammatory disorders including the inflammatory demyelinating disease of the central nervous system, multiple sclerosis (MS). The aim of the present study was to evaluate serum ghrelin levels in patients with MS. Serum ghrelin levels were measured in 40 MS patients and 20 controls. Control subjects were selected from healthy individuals, matched for age, sex and BMI. Fasting plasma levels of ghrelin were determined by radioimmunoassay. Serum ghrelin level was significantly higher in MS group (226.16 +/- 35.84 pg/ml, n=40) than that in the control group (113.04 +/- 11.28 pg/ml, n=20, P<0.001). Both, relapsing remitting and secondary progressive MS patients had ghrelin levels significantly higher than controls, while there was no significant difference between the ghrelin levels of patients with these two categories of MS. This study for the first time shows that patients with MS have higher levels of ghrelin and this increase in circulating ghrelin level may function against the proinflammatory process in these patients.

Ibuprofen reduces plasma nitrite/nitrate levels in a rabbit model of endotoxin-induced shock

OBJECTIVES

The purpose of this study was to investigate the effects of ibuprofen on plasma nitrite/nitrate levels, as indirect indicators of nitric oxide, in correlation with blood pressure in a rabbit model of endotoxin-induced shock.

METHODS

A total of 28 rabbits were randomly divided into four groups. Control group received physiological saline, while endotoxin (ETX, E. Coli, 055:B5, 2 mg/kg, i.v.) was administered to the rabbits in the other groups: group II receiving only ETX, in addition to ETX group III received ibuprofen (30 mg/kg) 30 minutes after ETX administration, whilst the group IV received ibuprofen (30 mg/kg) 30 minutes before ETX. Arterial blood pressure and plasma levels of nitrite/nitrate were determined immediately before (time 0) and 30, 60, 90, 120, 180, 240, and 300 minutes after ETX administration.

RESULTS

ETX administered groups had significantly higher plasma levels of nitrite/nitrate than the control group, at all consecutive measurements except at time O. Treatment with ibuprofen, either before or after ETX, partly restored the elevated levels of nitrite/nitrate. ETX also caused a significant decrease in blood pressure which was prevented in ibuprofen treated groups.

CONCLUSION

Results from this study indicate that administration of ibuprofen prevents sudden reductions in blood pressure by inhibiting excessive production of nitric oxide in rabbit model of endotoxin-induced shock and this may be of importance for providing crucial time for therapeutic intervention and survival in septic shock.

Inhibitory effects of sildenafil citrate on the tonus of isolated dog internal anal sphincter

PURPOSE

Although the exact pathogenesis of anal fissure is not known, hypertonicity of the internal anal sphincter might be involved in its pathogenesis as main event. To gain information about possible usefulness of the novel, smooth-muscle-relaxing drug, sildenafil, in chronic anal fissure, we investigated the effect of sildenafil citrate on acetylcholine-induced contractility of internal anal sphincter isolated from dogs.

METHODS

Internal anal sphincter strips were taken from German shepherd dogs and suspended in a tissue bath filled with Krebs solution at 37 degrees C (pH 7.4) continuously bubbled with 95 percent oxygen and 5 percent carbon dioxide, and isometric contractions were recorded. Contractions were evoked by 10 muM acetylcholine, and the effects of different concentrations of sildenafil citrate (0.1, 0.3, and 1 mM) on the isometric tension of each internal anal sphincter strip were examined. The statistical significance was analyzed by one-way analysis of variance.

RESULTS

Pretreatment with sildenafil citrate (0.1 mM) attenuated contractile response to acetylcholine (n = 3), which were significantly weak compared with the maximum contractile response to the acetylcholine alone (610 +/- 110 mg vs. 2,825.17 +/- 416 mg; n = 12; P < 0.05). Sildenafil citrate also significantly inhibited the acetylcholine-induced contractions in a dose-dependent manner when applied after.

CONCLUSIONS

This experimental in vitro study showed that sildenafil citrate relaxes acetylcholine stimulated contractions of isolated dog internal anal sphincter. This may be of importance for raising the possibility that sildenafil cit-rate may have future potential in the treatment of chronic anal fissure. Further studies are needed for a conclusive decision on possible usefulness of sildenafil citrate in patients with chronic anal fissure.

Removal of aniline from aqueous solution by PVC-CDAE ligand-exchanger

The adsorption of aniline from aqueous solutions onto cobalt(II)-poly(vinyl chloride)-carboxylated diaminoethane (PVC-CDAE) resin has been studied using a mini-column apparatus at 25+/-0.1 degrees C. First of all, experimental data obtained from the breakthrough curves were tested by using the Scatchard plot analysis, to have a preliminary prediction about the types of interaction of the resin with aniline. Our aim was to determine the model which best describes the experimental data. The aspect of the Scatchard plot indicated that the aniline adsorption did not follow the Langmuir model and the presence of two types of binding sites for aniline on the resin. However, the dynamics of aniline uptake were represented by the Freundlich model reasonably well. The kinetics of aniline adsorption from aqueous solution on the cobalt(II)-PVC-CDAE have also been tested using continuous column runs and rate-controlling step of the process was determined. In this study, homogeneous diffusion model was adapted to a column system to describe the change in the aniline concentration at the column exit beginning from breakthrough point as a function of time. Kinetic studies revealed that the rate-controlling step of the aniline adsorption was predominately film diffusion controlled rather particle diffusion.

The inhibitory role of melatonin on isolated guinea-pig urinary bladder: an endogenous hormone effect

OBJECTIVE

To investigate the effects of melatonin, an endogenous hormone, on acetylcholine and KCl-induced contractions of isolated guinea-pig detrusor muscle.

MATERIALS AND METHODS

Detrusor smooth muscle strips isolated from guinea-pig bladders were placed in an organ bath containing physiological saline at 37 degrees C and pH 7.4, constantly bubbled with 95% oxygen and 5% CO2. The effects of cumulatively applied melatonin on the acetylcholine- and KCl-induced contractions of isolated bladder strips were examined using isometric contraction measurements.

RESULTS

Melatonin (100 and 300 micromol/L) significantly inhibited the peak amplitude of both acetylcholine (10 micromol/L) and KCl (30 mmol/L)-induced contraction of the isolated bladder strips (P < 0.05). Similarly, melatonin caused a significant reduction in the contractile frequency induced by KCl (eight strips) in a concentration-dependent manner, while having no significant effect on the frequency of contractile response to acetylcholine, even at the highest concentration (300 micromol/L) used (P = 0.58, 14 strips).

CONCLUSIONS

These results suggest that melatonin inhibits acetylcholine- and KCl-induced contractions in isolated bladder strips from guinea pigs. The endogenous nature of melatonin, with its low side-effect profile, makes it a potentially useful agent to be considered in the medical management of the overactive bladder.

Effects of different weight loss protocols on serum leptin levels in obese females

We investigated the effects of different weight loss protocols on leptin levels in obese females with the aim of addressing the leptin resistance which has been found to be an aggravating factor in obesity. Twenty-four obese females enrolled to one of three 12-week weight loss protocols: orlistat-induced weight loss (OWL, n=8), exercise-induced weight loss (EWL, n=8) and orlistat plus exercise-induced weight loss (OEWL, n=8). Serum leptin levels were measured in duplicate by radioimmunoassay. There were significant reductions (P<0.01) in body weight and fat mass after the 12 week period in all groups: -11.4+/-0.5 kg and -9.8+/-0.5 kg (OEWL), -8.3+/-0.8 kg and -5.7+/-0.9 kg (OWL), -8.9+/-1.2 kg and -7.4+/-1.2 kg (EWL), respectively. Serum leptin levels were also decreased markedly in all groups: -59.2 % (OEWL1), -37.8 % (OWL) and -48.6 % (EWL) (P<0.01 all). In addition, there were marked decreases in leptin levels for each kilogram of fat mass after the 12 week period: -48.2+/-7.2 % (OEWL), -27.8+/-4.8 % (OWL) and -39.3+/-4.3 % (EWL) (P<0.01 all). Decreases in serum leptin levels expressed per kilogram of fat mass were significantly higher in the OEWL group compared to the OWL group (P=0.03). Consequently, an exercise training program in adjunct to pharmacotherapy provides higher weight reduction and fat mass loss in obesity treatment. It also seems to have further beneficial effects on leptin resistance, as indicated by decreases in leptin levels expressed per kilogram of fat mass.

Effects of different weight loss protocols on serum leptin levels in obese females

We investigated the effects of different weight loss protocols on leptin levels in obese females with the aim of addressing the leptin resistance which has been found to be an aggravating factor in obesity. Twenty-four obese females enrolled to one of three 12-week weight loss protocols: orlistat-induced weight loss (OWL, n=8), exercise-induced weight loss (EWL, n=8) and orlistat plus exercise-induced weight loss (OEWL, n=8). Serum leptin levels were measured in duplicate by radioimmunoassay. There were significant reductions (P<0.01) in body weight and fat mass after the 12 week period in all groups: -11.4+/-0.5 kg and -9.8+/-0.5 kg (OEWL), -8.3+/-0.8 kg and -5.7+/-0.9 kg (OWL), -8.9+/-1.2 kg and -7.4+/-1.2 kg (EWL), respectively. Serum leptin levels were also decreased markedly in all groups: -59.2 % (OEWL1), -37.8 % (OWL) and -48.6 % (EWL) (P<0.01 all). In addition, there were marked decreases in leptin levels for each kilogram of fat mass after the 12 week period: -48.2+/-7.2 % (OEWL), -27.8+/-4.8 % (OWL) and -39.3+/-4.3 % (EWL) (P<0.01 all). Decreases in serum leptin levels expressed per kilogram of fat mass were significantly higher in the OEWL group compared to the OWL group (P=0.03). Consequently, an exercise training program in adjunct to pharmacotherapy provides higher weight reduction and fat mass loss in obesity treatment. It also seems to have further beneficial effects on leptin resistance, as indicated by decreases in leptin levels expressed per kilogram of fat mass.

Assessment of Salivary and Serum Antioxidant Vitamins and Lipid Peroxidation in Patients with Recurrent Aphthous Ulceration

Recurrent aphthous ulceration (RAU) is a common oral mucosal disorder characterized by recurrent, painful oral aphthae. Although the exact cause of RAU is not known, local trauma, microorganisms, nutritional deficiencies, hormonal changes, genetics, and immunological factors have been suggested to contribute to its pathogenesis. The aim of this study was to assess the level of lipid peroxidation and status of antioxidant vitamins in patients with RAU. Thirty patients with RAU and 20 healthy controls were recruited. Vitamins A, E, and C and malondialdehyde (MDA) levels were measured in both serum and saliva of patients with RAU and control subjects by high performance liquid chromatography. Levels of vitamins A, E and C in both fluids were significantly lower (p < 0.05 for vitamins A and E, and p < 0.005 for vitamin C, respectively) in patients with RAU than in healthy control subjects. Conversely, the levels of MDA in serum and saliva were significantly higher (p < 0.005) in patients with RAU than in the control group. Furthermore, strong and highly significant correlation was found between serum and salivary levels of vitamins A, E and C, and MDA in patients with RAU (r > or = 0.90, p < 0.0001). The present study demonstrates that the serum and saliva levels of selected antioxidant vitamins are lower, while the degree of lipid peroxidation, as judged by the MDA levels, is higher in patients with RAU than in the control subjects. This is the first to measure specific antioxidant levels in both saliva and blood in the same patients, and indicates that the non-enzymatic anti-oxidant ability is impaired in patients with RAU.

Adsorption of indole and 2-methylindole on ligand-exchange matrix

The adsorption of indole and its 2-methyl derivative from aqueous solutions onto cobalt(II)-carboxylated diaminoethane sporopollenin (CDAE-sporopollenin) was studied using a fixed-bed column at 25+/-0.1 degrees C. Minicolumn adsorption studies showed that the breakthrough and the total adsorption capacities of CDAE-sporopollenin in the concentration range we have studied increased with increasing external ligand concentration. The characteristics of the adsorption process were investigated using Scatchard plot analysis, where the equilibrium binding data for indole on ligand exchanger gave rise to a linear plot. However, for 2-methylindole, divergence from the Scatchard plot was evident, consistent with the participation of secondary equilibrium effects in the adsorption process. The adsorption behaviors of ligands on CDAE-sporopollenin were expressed by both the Langmuir and Freundlich isotherms. The adsorption isotherm data for these ligands on the resin can be satisfactorily fitted to the Freundlich isotherm within the concentration range studied. However, in the case of 2-methylindole, the experimental data did not fit the Langmuir model, especially when a high ligand concentration range is used; this is probably due to the nonspecific interactions between the ligand exchange matrix and the methyl group present. Ligand adsorption constants and correlation coefficients for the ligands were calculated from the Langmuir and Freundlich isotherms.

Investigation of the influence of training status on the relationship between the acute exercise and serum leptin levels in obese females

OBJECTIVE

Recent studies have concluded that an energy expenditure by an acute exercise session has no immediate effect on leptin levels while some showed a decline in leptin levels. The purpose of this study was to investigate any possible effects of training status of the subjects on acute exercise-leptin relationship in obese patients.

MATERIALS AND METHODS

Fourteen obese sedentary females were enrolled to the study and effects of acute incremental exercise on serum leptin levels were determined at rest and at maximal exercise performance. Then, they participated to a 12-weeks endurance aerobic training programme performed in the laboratory on a computer controlled cycle ergometer and their leptin levels were re-evaluated and the leptin-acute exercise relationships obtained under different training levels in the same group of subjects were compared. The body compositions were determined by bioelectrical impedance. Pre and post training blood samples were taken at rest and at the maximal exercise performance. Serum leptin levels were analysed in duplicate by RIA. Data were evaluated using, paired t and Pearson's tests.

RESULTS

Leptin levels were not acutely affected by the incremental exercise either before (23.62+/-3.5 ng/ml and 22.62+/-3.6 ng/ml) or after (13.13+/-3.4 ng/ml and 13.82+/-3.6 ng/ml) endurance training. The marked decrease in leptin levels following training was closely correlated with fat mass loss R= 0.899 (P= 0.0001).

CONCLUSIONS

This study indicates that an increase in energy expenditure by acute exercise has no significant acute effect on leptin level regardless of the training status of the subjects and decrease in leptin levels after a 12-weeks endurance aerobic training programme are closely associated with the fat mass loss.

Effects of gentamicin sulfate on the contractility of myometrium isolated from non-pregnant cows

Gentamicin sulfate, an aminoglycoside antibiotic known to cause depression of neuromuscular function, is a drug of choice in intrauterine antibiotic treatment of bovine chronical or subclinical uterine infections but its effects on the contractility of the cow uterus have not been studied. The aim of this study was to characterize, in vitro, the effect of gentamicin sulfate on spontaneous as well as prostaglandin F2alpha (PGF2alpha) and oxytocin-induced contractility of the non-pregnant cow uterus. Myometrial strips were isolated from non-pregnant cows in follicular phase and suspended in a jacketed organ bath filled with Krebs solution at 37 degrees C (pH 7.4) continuously bubbled with 95% oxygen and 5% carbon dioxide and isometric contractions were recorded using isometric force displacement transducer. After manifestation of the spontaneous contractions during equilibration period the test substances PGF2alpha (1 microM), oxytocin (2.5 mIU/ml bath fluid) and gentamicin sulfate (150-600 microm) were added to the bath. The effects of gentamicin sulfate on amplitude (g) and frequency of spontaneous and the agonist-induced contractions were evaluated by 20 min intervals. Data were statistically analyzed using the Student's t-test and Wilcoxon signed-rank test where appropriate. P <0.05 was considered to be significant. Gentamicin sulfate inhibited spontaneous, as well as oxytocin or PGF2alpha-induced contractions in a dose-dependent manner. Although both the frequency and amplitude of contractions were significantly inhibited by gentamicin sulfate, the effect on the frequency of the spontaneous and agonist-induced contractions were more prominent than on the amplitude. The result from this in vitro study indicated that gentamicin sulfate inhibits spontaneous as well as oxytocin and PGF2alpha-induced contractions of myometrium isolated from non-pregnant cows. This may be of importance considering the potentially negative effect of gentamicin sulfate on uterine involution in cows with puerperal endometritis, resulting in impairment of fertility performance.

Epidemiological features of irritable bowel syndrome in a Turkish urban society

BACKGROUND AND AIM

Irritable bowel syndrome (IBS) is a widespread functional bowel disorder and its prevalence in Western societies ranges from 3-20%. The present study aimed to determine the prevalence of IBS in eastern Turkey, particularly in urban parts of Elazig where 250 000 people live.

METHODS

Of the 18 primary care centers, four were randomly selected for this study. All individuals (aged >17 years) living around the service area of these health centers were included. A total of 1900 subjects were randomly selected using the personal health records from the primary care centers. The total number of subjects that could be contacted was 1766. A questionnaire with multiple choice questions was applied to the subjects by medical students using the face-to-face technique. Prevalence of IBS and distribution of symptoms were evaluated by the Rome II criteria.

RESULTS

Of the 1766 subjects, 45.4% were male and 54.6% were female. Prevalence of IBS was 5% in males, 7.4% in females and 6.3% overall. The percentage of subjects with IBS in the 17-30 years age group was 26.2%; 52.3% in the 30-50 years age group and 21.6% in the above 50 years age group. Prevalence of IBS was highest (10.2%) in persons who were illiterate and lowest (3.0%) in university graduates. A positive correlation was determined between low economical status and prevalence of IBS (P < 0.05).

CONCLUSION

Although IBS is widely present in Turkey, its prevalence is lower than that reported in Western communities. In the region where this study was carried out, IBS was more prevalent in females and in individuals with low educational and economical status.

Diminished cellular and humoral immunity in workers occupationally exposed to low levels of ionizing radiation

BACKGROUND

It has been reported that subgroups of T-lymphocytes are affected at different levels and different cell groups of immune system give different responses in individuals exposed to long-term ionizing radiation. The aim of this study was to investigate the effect of occupational exposure to low levels of ionizing radiation in selected indices of cellular and humoral immunity in radiology workers.

METHODS

Level of subgroups of peripheral blood lymphocytes, complements (C(3), C(4)), and total immunoglobulins (IgG, IgA, IgM) were analyzed in 50 radiology workers occupationally exposed to low levels of ionizing radiation and 35 age-matched healthy controls.

RESULTS

CD4(+) T lymphocyte (T-helper) levels were determined as significantly low in radiology workers exposed to ionizing radiation compared with controls (p <0.05). There were no statistically significant differences in groups in terms of other subgroups of lymphocytes (p >0.05). In addition, levels of serum total IgG, IgA, IgM, C(3,) and C(4) were determined as significantly lower in workers exposed to ionizing radiation compared with controls (p <0.001). Total IgA and IgM levels in radiology workers who were smokers were determined as significantly lower compared with non-smoking radiology workers (p >0.05).

CONCLUSIONS

Levels of CD4(+) T lymphocytes and humoral immune response (total immunoglobulins and complements) were determined as weaker in workers exposed to low levels of ionizing radiation compared with controls, indicating the importance of taking appropriate measures to protect radiology workers from exposure to ionizing radiation and for these workers to avoid smoking. Further studies are needed for determining the appropriateness of periodic check-ups of immune functions and the most efficient and cost-effective ways of monitoring immune functions in radiology workers for detecting early changes in the immune system.

[Biochemical and immunological effects of ionizing radiation in radiology staff members]

PURPOSE

This study aimed to investigate the influence of occupational exposures to long term low-dose ionizing radiation on blood biochemistry and immunity levels of the radiology staff.

MATERIALS AND METHODS

Fifty-one subjects, aged between 21-57 years (30.06+/-7.02 years), working in the department of radiology were enrolled to this study. Twenty-five subjects (49.1%) were female and 26 (50.9%) were male. Control group consisted of 40 healthy non-smoking subjects aged between 20-60 years (mean 31.5+/-5.75) who had never been exposed to radiation; 19 (47.5%) of these were female and 21 (52.5%) male. Venous blood samples were obtained from the radiology staff and control group and immunological and biochemical analysis of samples were performed.

RESULTS

CD4+ T-lymphocyte ratio, and serum total IgA, IgG, IgM and C3, C4 levels were lower in the radiology staff compared to the controls. Serum triglycerides and paraoxonase activities were increased in the radiology staff (p<0.05).

CONCLUSION

In radiology workers exposed to long-term low-dose ionizing radiation, levels of the CD4+ T lymphocytes, total immunoglobulins (IgA, IgG, IgM), C3 and C4 levels were lower, while serum trygliceride levels and paraoxonase activities were significantly higher (p<0.05). IgA and IgM levels of smoker radiology workers were significantly lower than non-smoker radiology workers (p<0.05). Since the staff members of department of radiology are vulnerable to the side effects in parallel to the dose of radiation being exposed, we think that in addition to avoiding radiation as much as possible, they should have periodical blood biochemistry and immune function tests.

Biosorption of nickel(II) and copper(II) ions from aqueous solution by Streptomyces coelicolor A3(2)

The biosorption of nickel(II) and copper(II) ions from aqueous solution by dried Streptomyces coelicolor A3(2) was studied as a function of concentration, pH and temperature. The optimum pH range for nickel and copper uptake was 8.0 and 5.0, respectively. At the optimal conditions, metal ion uptake was increased as the initial metal ion concentration increased up to 250 mg l(-1). At 250 mg l(-1) copper(II) ion uptake was 21.8% whereas nickel(II) ion uptake was found to be as high as 7.3% compared to those reported earlier in the literature. Metal ion uptake experiments were carried out at different temperatures where the best ion uptake was found to be at 25 degrees C. The characteristics of the adsorption process were investigated using Scatchard analysis at 25 degrees C. Scatchard analysis of the equilibrium binding data for metal ions on S. coelicolor A3(2) gave rise to a linear plot, indicating that the Langmuir model could be applied. However, for nickel(II) ion, divergence from the Scatchard plot was evident, consistent with the participation of secondary equilibrium effects in the adsorption process. Adsorption behaviour of nickel(II) and copper(II) ions on the S. coelicolor A3(2) can be expressed by both the Langmuir and Freundlich isotherms. The adsorption data with respect to both metals provide an excellent fit to the Freundlich isotherm. However, when the Langmuir isotherm model was applied to these data, a good fit was obtained for the copper adsorption only and not for nickel(II) ion.

Possible effects of melatonin on thymus gland after pinealectomy in rats

OBJECTIVES

The purpose of this study was to investigate the effects of pinealectomy and pinealectomy plus melatonin administration on thymus weight and histology in adult Wistar-albino rats.

METHODS

The animals were divided into three groups. Group I and Group II were designated as control (sham-pinealectomized) and pinealectomized rats, respectively. They received 10% ethanol (0.1 ml per day s.c.) alone. The rats in Group III were pinealectomized and daily injected with melatonin (3 mg/kg/0.1 ml 10% ethanol per day s.c.) commencing on the day seven after surgical operation. Injections were applied for two months.

RESULTS

The thymus atrophied and its weight decreased after pinealectomy (p<0.001). The cortico-medullary boundary could not be distinguished and in the thymus induced a loss of lymphoid elements, increased number of phagocytic macrophages and enlarged blood vessels. Melatonin prevented the thymic involution.

CONCLUSIONS

These results suggest that pinealectomy decreases thymus weight and that long-term administration of melatonin restores thymus weight to normal levels.

Effects of body mass index on maximal work production capacity and aerobic fitness during incremental exercise

The aim of this study was to investigate the relationship between cardiopulmonary fitness as indicated by maximal work rate (Wmax) production and aerobic capacities (WAT), body mass index (BMI) and heart rate reserve. A total of 60 sedentary subjects (30 males, 30 females, aged 18-25 years) were enrolled in the study. Each subject performed an incremental exercise test (15 W/min) to the limit of tolerance on an electromagnetically-braked cycle ergometer. There was a negative correlation between increased BMI to Wmax capacity per kilogram body weight in male (r=-0.846, P=0.0001) and in female (r=-0.896, P=0.0001) subjects. In addition, W(AT) for each kilogram body weight also negatively correlated with increased BMI in male (r=-0.870, P=0.0001) and in females (r=-0.807, P=0.0001). The heart rate reserve correlated negatively with increasing BMI: r=-0.699, P=0.0001 (males) and r=-0.655, P=0.0001 (females). The results of the present study have suggested that, due to the inverse correlation between BMI, Wmax capacity, aerobic fitness and heart rate reserve, it may be useful to consider BMI in establishing cardiopulmonary fitness in various subjects.

Selective Extraction of Iron(III) from Aqueous Nitrate Solution in the Presence of Cobalt(II), Copper(II) and Nickel(II) Ions Using Bis(.DELTA.2-2-imidazolinyl)-5,5'-dioxime

The feasibility of using bis(delta2-2-imidazolinyl)-5,5'-dioxime (H2L) for the selective extraction of iron(III) from aqueous solutions was investigated by employing an solvent-extraction technique. The extraction of iron(III) from an aqueous nitrate solution in the presence of metal ions, such as cobalt(II), copper(II) and nickel(II), was carried out using H2L in binary and multicomponent mixtures. Iron(III) extraction has been studied as a function of the pH, equilibrium time and extractant concentration. From the extracted complex species in the organic phase, iron(III) was stripped with 2 M HNO3, and later determined using atomic-absorption spectrometry. The extraction was found to significantly depend on the aqueous solution pH. The extraction of iron(III) with H2L increases with the pH value, reaching a maximum in the zone of pH 2.0, remaining constant between 2 and 3.5 and subsequently decreasing. The quantitative extraction of iron(III) with 5 x 10(-30 M H2L in toluene is observed at pH 2.0. H2L was found to react with iron(III) to form ligand complex having a composition of 1:2 (Fe:H2L).

Effects of body mass index on maximal work production capacity and aerobic fitness during incremental exercise test

The aim of this study was to investigate the relationship between cardiopulmonary fitness as indicated by maximal work rate (Wmax) production and aerobic capacities (WAT), body mass index (BMI) and heart rate reserve. A total of 60 sedentary subjects (30 males, 30 females, aged 18-25 years) were enrolled in the study. Each subject performed an incremental exercise test (15 W/min) to the limit of tolerance on an electromagnetically-braked cycle ergometer. There was a negative correlation between increased BMI to Wmax capacity per kilogram body weight in male (r=-0.846, P=0.0001) and in female (r=-0.896, P=0.0001) subjects. In addition, W(AT) for each kilogram body weight also negatively correlated with increased BMI in male (r=-0.870, P=0.0001) and in females (r=-0.807, P=0.0001). The heart rate reserve correlated negatively with increasing BMI: r=-0.699, P=0.0001 (males) and r=-0.655, P=0.0001 (females). The results of the present study have suggested that, due to the inverse correlation between BMI, Wmax capacity, aerobic fitness and heart rate reserve, it may be useful to consider BMI in establishing cardiopulmonary fitness in various subjects.

The correlation between plasma homocysteine and malondialdehyde levels in preeclampsia

OBJECTIVE

To investigate the possible correlation between plasma malondialdehyde and homocysteine levels of preeclamptic patients.

DESIGN

Venous blood samples of 20 preeclamptics and 20 healthy pregnant controls were collected. Plasma malondialdehyde and homocysteine concentrations were measured and the correlation between them was investigated. Mann Whitney U test and Spearman correlation analysis were used for statistical analysis.

SETTING

University of Firat, Medical School.

RESULTS

Plasma malondialdehyde and homocysteine concentrations were higher in preeclamptic patients (p<0.05) and a positive correlation between these parameters was found (r: 0.77, p<0.01, n:20).

CONCLUSION

Our results may put forward some new strategies in the research of etiopathogenesis and treatment of preeclampsia.

Hyperhomocysteinemia may be a resistance factor in tocolytic treatment with β mimetics

Homocysteine is an intermediate amino acid in the methionine metabolism which does not take place in the structure of proteins. Plasma homocysteine levels can be elevated by a variety of genetic and nutritional factors. Hyperhomocysteinemia is an independent risk factor for cardiovascular diseases and common obstetric problems. Mildly elevated levels of homocysteine have been implicated in a number of disease processes such as atherosclerotic vascular disease and adverse obstetrical outcome. It was shown that the presence of high homocysteine concentrations in the in vitro system had an activating role in myometrial contractions. It is hypothesized that hyperhomocysteinemia in pregnancy is associated with preterm labor in consequence of myometrial contractions. Hyperhomocysteinemia, therefore, could be a treatable cause of this important public health and obstetric concern.

Effects of melatonin and oxytetracycline in autologous intraperitoneal ovary transplantation in rats

OBJECTIVES

To comparatively investigate the effects melatonin and oxytetracycline as antioxidants on autologous intraperitoneal ovary transplantation in rats.

SETTING AND DESIGN

28 adult female Wistar rats with regular estrous cycles were randomly divided into four groups. Group 1 (n=7) was the control group; Group 2 (n=7) bilateral oophorectomy and intraperitoneal transplantation group; and Groups 3 (n=7) and 4 (n=7) firstly received 20 mg/kg/IP melatonin and 10 mg/kg/IP oxytetracycline., respectively and fifteen minutes after that, they had bilateral oophorectomy and intraperitoneal transplantation. Ovarian tissue and blood malondialdehyde (MDA) levels, superoxide dismutase (SOD) and glutathione peroxidase (GSHPx) levels were determined. Vaginal cytology and ovarian necrosis were histopathologically investigated. Kruskall Wallis analysis of variance was used in the statistical analysis of data.

RESULTS

Ovarian necrosis, tissue MDA and plasma MDA levels were significantly higher in Group 2 compared to the Groups 1, 3 and 4 (p<0.03). SOD and GSHPx levels were significantly lower in group 2 compared to the groups 1, 3 and 4 (p<0.03). Melatonin was found to be more effective on ovarian necrosis and tissue MDA level than the use of oxytetracycline following autologous intraperitoneal ovary transplantation (p<0.03). There was a significant positive correlation between tissue MDA level and ovarian necrosis and a very strong negative correlation between tissue MDA and SOD level (rs = +/-0.9, n=28, p=0.000).

CONCLUSION

Although both melatonin and oxytetracycline were found to be effective in autologous intraperitoneal pelvic ovary transplantation, melatonin is more effective against both the ovarian necrosis and tissue MDA level in rats.

Homocysteine-induced enhancement of spontaneous contractions of myometrium isolated from pregnant women

BACKGROUND

Although many associations have been demonstrated between hyperhomocysteinemia and pregnancy complications, such as spontaneous abortion, preterm labor, preeclampsia and low birthweight, it is still not clear whether hyperhomocysteinemia is the cause or the consequence of these pregnancy complications. The aim of this study was to investigate the effects of homocysteine on the spontaneous contractility of isolated pregnant human myometrium.

METHODS

Myometrium samples obtained from women undergoing elective caesarean section were suspended in a jacketed organ bath containing Krebs' solution at 37 degrees C (pH 7.4), continuously gassed with 95% O2 and 5% CO2. After manifestation of spontaneous contractions under 2 g of resting tension, homocysteine was applied to the organ bath, and amplitude and frequency of contractions were evaluated at 20-min intervals. Statistical analysis of amplitude and frequency of the contractions was performed using the Kruskal-Wallis analysis of variance test.

RESULTS

Application of 0.1 mm homocysteine had no significant effect on either frequency (4.63 +/- 0.42 vs. 4.01 +/- 0.53 for the control period; p > 0.05) or amplitude (3.20 +/- 0.07 g vs. 3.15 +/- 0.07 g; p > 0.05) of spontaneous contractions, while 1 and 2 mm homocysteine significantly increased the frequency (8.54 +/- 0.62 vs. 3.9 +/- 0.44, p < 0.02, and 12.32 +/- 0.72 vs. 3.96 +/- 0.51, p < 0.001, respectively) of spontaneous contractions but caused only a modest change in amplitude (2.92 +/- 0.04 g vs. 2.87 +/- 0.05 g, p > 0.05, and 3.02 +/- 0.06 g vs. 2.93 +/- 0.05 g, p > 0.05, respectively).

CONCLUSION

Results from this study indicate for the first time that homocysteine causes enhancement of spontaneous contractions of myometrium derived from pregnant women.

The effects of photoperiod on testes in rat: a morphometric and immunohistochemical study

OBJECTIVE

The aim of this study was to examine the effects of photoperiod on testes in rat.

DESIGN

For this purpose 21 male Wistar rats were used. Animals were divided into three groups. Control rats in group I were kept under 12 hrs light: 12 hrs dark conditions (12L: 12D) for 10 weeks. Animals in group II were exposed to long photoperiods (18L: 6D), while rats in group III were exposed to short photoperiods (6L: 18D) for 10 weeks. At the end of the experiment, all animals were killed by decapitation and blood samples were obtained. Serum testosterone levels were determined with the use of a chemiluminescent enzyme immunoassay. The testes of all rats were removed and weighed. Testicular tissue was processed semiquantitative evaluation of immunohistochemical testosterone staining. Intensity of immunostaining was determined on a scale between 0 (no staining) and 5 (heavy staining). For morphometric comparison, diameters of seminiferous tubules in each group were measured.

RESULTS

In rats exposed to long photoperiods, testicular weights, diameters of seminiferous tubules and serum testosterone levels were significantly increased as compared to those in control rats. Whereas, exposure of rats to short photoperiods resulted in significantly decrease of testicular weights, diameters of seminiferous tubules and serum testosterone levels as compared to those in control rats and rats maintained in long photoperiods. Immunostaining of testosterone was moderate (3+) in control rats, heavy (5+) in rats exposed to long photoperiods and minimal (1+) in rats exposed to short photoperiods.

CONCLUSIONS

The results of our study indicate that testicular functions increase after exposure to long photoperiods and decrease after exposure to short photoperiods.

The H- and T-reflex response parameters of long- and short-distance athletes

It is well known that the training level of a muscle belongs to the parameters that affect the H-reflex response amplitude. The aim of this study was to investigate the effects of training type on H- and T-reflex response parameters. For this purpose, 20 long-distance athletes (group I, test group), 18 short-distance athletes (group II, test group) and 20 non-trained subjects (group III, control group) were involved in this study in which the H- and T-reflex amplitude and latency values were measured. The H-reflex amplitude and latency values found in groups I, II and III were 3.64 +/- 0.28 mV and 26.88 +/- 1.45 ms, 3.17 +/- 0.26 mV and 26.19 +/- 1.89 ms, and 6.07 +/- 0.34 mV and 26.77 +/- 1.32 ms, respectively. The T-reflex amplitude and latency values of the groups I, II and III were 3.30 +/- 0.18 mV and 32.01 +/- 1.02 ms, 3.11 +/- 0.20 mV and 31.47 +/- 1.16 ms, 4.24 +/- 0.21 mV and 31.47 +/- 1.16 ms, respectively. There was no statistically significant difference between the groups with respect to latencies of H- and T-reflexes (p>0.05). In both test groups, the amplitudes of the H-reflex and T-reflex were significantly smaller than the control group (p<0.05). The results of this study suggest that training of muscles affect the H- and T-reflex response parameters.

The inhibitory effects of dantrolene on action potential-induced calcium transients in cultured rat dorsal root ganglion neurons

We investigated the actions of dantrolene Ca(2+)-induced on Ca(2+)-release (CICR) evoked by action potentials in cultured rat sensory neurons. The effect of dantrolene on action potential after-depolarization and voltage-activated calcium currents was studied in cultured neonatal rat dorsal root ganglion cells (DRG) using the whole-cell patch-clamp technique. Depolarizing current injection evoked action potentials and depolarizing after-potentials, which are activated as a result of CICR following a single action potential in some cells. The type of after-potentials was determined by inducing action potentials from the resting membrane potential. Extracellular application of dantrolene (10 microM) abolished after-depolarizations without affecting action potential properties. Furthermore, dantrolene significantly reduced repetitive action potentials after depolarizing current injection into these neurons, but had no significant effect on the steady-state current voltage relationship of calcium currents in these neurons. We conclude that dantrolene inhibits the induction of action potential after depolarizations by inhibiting CICR in cultured rat sensory neurons.