Effect of hypothermia on blood-brain barrier permeability following traumatic brain injury in chronically ethanol-treated rats.

The objective of this study was to investigate the effect of hypothermia on the blood-brain barrier (BBB) disruption caused by traumatic brain injury (TBI) in chronically ethanol-treated rats. BBB permeability was measured using Evans blue (EB) dye. Arterial blood pressure levels of animals in hypothermic groups decreased significantly. The EB dye extravasation into the brain significantly increased in hypothermia and at 6 and 24 h after TBI. In ethanol-treated rats that were subjected to TBI, hypothermia led to a significant decrease in EB dye content in the brain at 24 h but not at 6 h after TBI when compared with TBI alone.

Effects of lipopolysaccharide on the blood-brain barrier permeability in prolonged nitric oxide blockade-induced hypertensive rats.

The authors investigated the effects of lipopolysaccharide (LPS) on the blood-brain barrier (BBB) integrity and the activity of astrocytes during the Nw-nitro-L-arginine methyl ester (L-NAME) hypertension followed by angiotensin (ANG) II in rats. They measured the changes in the BBB permeability using the Evans blue (EB) dye and concomitantly in the levels of TNF-a, IL-1b, and IL-6 in serum and nitric oxide in plasma. The authors performed two tight junction-specific proteins, zonula occludens-1 and occludin, and glial fibrillary acidic protein, by using immunohisto-chemical method. The serum levels of TNF-a, IL-1 IL-6, and the plasma level of nitric oxide significantly increased in LPS-treated rats (p<.01). The EB dye extravasation increased in cerebellum (p<.001) and diencephalon (p<.05) of L-NAME plus ANG II-treated animals. However, LPS reduced the increased EB dye extravasation in the brain regions of L-NAME-induced hypertensive rats treated with ANG II (p<.001). In L-NAME, there was a considerable loss of staining in both zonula occludens-1 and occludin. Staining for zonula occludens-1 and occludin was highly intensive in animals treated with LPS. Glial fibrillary acidic protein staining was seen in a few astrocytes in brains of L-NAME-treated animals. However, this staining showed an increased intensity in the brain sections of animals treated with LPS. This study indicates that, in L-NAME hypertensive rats, ANG II leads to an increase in the extravasation of EB dye to brain as a result of decreased activity of tight junction proteins and astrocytes, and LPS could significantly attenuate the EB dye transport to the brain through the increased activity of tight junction proteins and astrocytes.

Transfusional transmitted virus seroprevalence in asymptomatic HBsAg (+) hepatitis B carriers.

BACKGROUND: The aim of this study was to evaluate the transfusional transmitted virus (TTV) seroprevalence in asymptomatic HBsAg (+) patients and to assess the influence of TTV on the course of these patients. METHODS: Sixty asymptomatic HBV carriers were included and 31 healthy volunteers served as controls. Cases were followed at 6-month intervals for a total duration of 4 years. RESULTS: In the asymptomatic carrier group, 31 patients (51.7%) had a history of surgery and 10 (16.7%) had a history of blood transfusions. TTV-DNA was detected in 45 of these patients (75%). In the control group, 12 patients (38.7%) had a history of surgery and 2 had (6.5%) a history of blood transfusions. TTV-DNA was found in 20 (64.5%) of these subjects. The incidence of TTV-DNA positivity was not significantly different between the two groups (P > 0.05). CONCLUSION: In spite of the common occurrence of HBV and TTV, TTV-DNA was also detected in 64.5% of healthy controls. Furthermore, during 4 years of follow up, TTV had no detrimental effects on the course of asymptomatic HBV carriers. These results suggest that the hepatic injury due to TTV is insignificant in this group of patients.

Effect of losartan on the blood-brain barrier permeability in diabetic hypertensive rats.

Our previous publication has stressed the benefits of losartan, an angiotensin II receptor blocker, on the permeability of blood-brain barrier (BBB) and blood pressure during L-NAME-induced hypertension. This study reports the impacts of anti-hypertensive treatment by losartan on the brain endothelial barrier function and the arterial blood pressure, during acute hypertension episode, in experimentally diabetic hypertensive rats. Systolic blood pressure measurements were taken with tail cuff method before and during administration of L-NAME (0.5 mg/ml). We induced diabetes by using alloxan (50 mg/kg, i.p). Losartan (3 mg/kg, i.v) was given to rats following the L-NAME treatment. Acute hypertensive vascular injury was induced by epinephrine (40 microg/kg). The BBB disruption was quantified according to the extravasation of the Evans blue (EB) dye. L-NAME induced a significant increase in arterial blood pressure on day 14 in normoglycemic and hyperglycemic rats (p < 0.05). Losartan significantly reduced the increased blood pressure in hypertensive and diabetic hypertensive rats (p < 0.01). Epinephrine-induced acute hypertension in diabetic hypertensive rats increased the content of EB dye dramatically in cerebellum and diencephalon (p < 0.01) and slightly in both cerebral cortex (p < 0.05). Losartan treatment reduced the increased BBB permeability to EB dye in the brain regions of diabetic hypertensive rats treated with epinephrine (p < 0.05). This study indicates that, in diabetic hypertensive rats, epinephrine administration leads to an increase in microvascular-EB-albumin efflux to brain, however losartan treatment significantly attenuates this protein's transport to brain tissue.

Effect of aluminum on the blood-brain barrier permeability during nitric oxide-blockade-induced chronic hypertension in rats.

We examined the effect of aluminum on the permeability of the blood-brain barrier (BBB) during nitric oxide-blockade-induced chronic hypertension in rats. Animals were given the inhibitor of nitric oxide synthase, L-NAME (Nomega-nitro-L-arginine methyl ester), for 4 wk to induce chronic hypertension. Two groups of rats were given an intraperitoneal injection of aluminum chloride. The integrity of the BBB was assessed by a quantitative measurement for Evans blue (EB) dye. The arterial blood pressure in L-NAME- and L-NAME plus aluminum-treated animals was significantly elevated from 115+/-2.8 and 110+/-1.7 mm Hg to 174+/-5.2 and 175+/-4.8 mm Hg, respectively (p < 0.01). The EB dye content in the brain regions of the rats in the L-NAME group was increased, but there was no statistical significance compared to the saline group. The extravasation of EB dye was significantly increased in the brain regions of the animals treated with aluminum compared to the rats treated with saline (p < 0.05). A significantly higher EB dye content in the brain regions was observed in the L-NAME plus aluminum group compared to L-NAME, aluminum, and saline groups (p < 0.01). These findings indicate that exposure to a high level of aluminum leads to an additional increase in BBB permeability where nitric oxide-blockade-induced chronic hypertension potentiates the effect of aluminum to enhance BBB permeability to EB dye.

Comparison of morphological changes in white blood cells after death and in vitro storage of blood for the estimation of postmortem interval.

Estimation of the time of death is one of the most important problems for forensic medicine and law. Physical and chemical postmortem changes are evaluated together while estimating the time of death. In this study, in vitro storage and postmortem changes of white blood cells were aimed to be compared within the given postmortem interval, and a follow-up study was carried out. Blood smears which were obtained from 10 non-refrigerated cadavers (experimental group) and from 40 hospital patients (control group) have been evaluated to observe and compare changes during the in vitro storage and postmortem degenerative morphological changes that white blood cells undergo throughout the given postmortem intervals. The samples were examined by using a light microscope, and blood cells were differentiated by staining blood films with May-Grunwald stain, followed by Giemsa stain. Identifiable degenerated eosinophils and monocytes were first examined at 6h of death and the in vitro storage, and they were unidentifiable beyond 72 h of storage. Identifiable degeneration of neutrophils were first examined at 6h of death and storage while unidentifiable beyond 96 h of storage. Identifiable degeneration of lymphocytes were first examined at 24h of death, and they were still identifiable beyond 120 h. Cellular changes of leukocytes can be useful in the 6-120 h for estimating the time of in vitro storage, and the findings match during the first 21 h for both experimental and control groups. Finally, this follow-up study and the comparison will also be carried out for a longer postmortem interval, and other specific hypothesis that relate cellular changes in tissues other than blood with time since death are various points that needs to be studied.

Magnesium sulfate attenuates increased blood-brain barrier permeability during insulin-induced hypoglycemia in rats.

Magnesium probably protects brain tissue against the effects of cerebral ischemia, brain injury and stroke through its actions as a calcium antagonist and inhibitor of excitatory amino acids. The effects of magnesium sulfate on cerebrovascular permeability to a dye, Evans blue, were studied during insulin-induced hypoglycemia with hypothermia in rats. Hypoglycemia was induced by an intramuscular injection of insulin. After giving insulin, each animal received MgSO4 (270 mg/kg) ip, followed by a 27 mg/kg dose every 20 min for 2.5 h. Plasma glucose and Mg2+ levels of animals were measured. Magnesium concentrations increased in the serum following MgSO4 administration (6.05+/-0.57 vs. 2.58+/-0.14 mg/dL in the Mg2+ group, and 7.14+/-0.42 vs. 2.78+/-0.06 mg/dL in the insulin + Mg2+ group, P < 0.01). Plasma glucose levels decreased following hypoglycemia (4+/-0.66 vs. 118+/-2.23 mg/dL in the insulin group, and 7+/-1.59 vs. 118+/-4.84 mg/dL in the insulin + Mg2+ group, P < 0.01). Blood-brain barrier permeability to Evans blue considerably increased in hypoglycemic rats (P < 0.01). In contrast, blood-brain barrier permeability to Evans blue was significantly reduced in treatment of hypoglycemic rats with MgSO4 (P < 0.01). These results indicate that Mg2+ greatly reduced the passage of exogenous vascular tracer bound to albumin into the brain during hypoglycemia with hypothermia. Mg2+ could have protective effects on blood-brain barrier permeability against insulin-induced hypoglycemia.

The attitudes of medical students to autopsy.

To assess the attitudes of medical students to autopsy, 6th year students in the Medical Schools located in Istanbul, Edirne and Bursa in Turkey were asked to participate in a questionnaire. In the questionnaire, the main questions were on the number of autopsies they had attended, the number of autopsies they had participated in, their reaction to the first autopsy, whether they felt the conditions were adequate or not and what would their objectives be upon deciding to perform an autopsy. In the evaluation, it was detected that most of the participants had attended an autopsy, only a minority had participated in autopsy and most of them felt uncomfortable and inadequate on performing autopsy. The results were discussed with respect to the literature.

Virginity examinations in Turkey: role of forensic physicians in controlling female sexuality.

CONTEXT: Although the Turkish Medical Association has deemed "virginity examinations" a form of gender-based violence, women in Turkey are often subjected to such examinations by forensic physicians for both legal and social reasons. Little is known about these physicians' role and attitudes in this practice. OBJECTIVES: To assess forensic physicians' experiences and attitudes regarding virginity examinations in Turkey and suggest potential solutions to the problems identified. DESIGN: Cross-sectional self-administered survey. SETTING: Surveys were completed during the Forensic Science Congress held in Kusadasi in April 1998 as well as in urban academic and medical practice settings between April and October 1998. PARTICIPANTS: Of 158 physicians who practice, are formally trained in, or are in training for forensic medicine, 118 completed the survey (response rate, 74.7%). MAIN OUTCOME MEASURES: Frequency and circumstances of conducting virginity examinations, opinions regarding beneficial and adverse consequences of these examinations, and recommendations for changing the practice, as measured by a 100-item questionnaire. RESULTS: Overall, survey respondents reported conducting 5901 examinations in the previous 12 months; 4045 were conducted because of alleged sexual assault and 1856 for social reasons. Although 68% of forensic physicians indicated that they believed virginity examinations are inappropriate in the absence of an allegation of sexual assault, 45% had conducted examinations for social reasons. The majority of the respondents (93%) agreed that the examinations are psychologically traumatic for the patient. In addition, more than half (58%) reported that at least 50% of patients undergo examinations against their will. CONCLUSIONS: Nearly half of forensic physicians in Turkey conduct virginity examinations for social reasons despite beliefs that such examinations are inappropriate, traumatic to the patient, and often performed against the patient's will. Physicians' participation in such practices is inconsistent with principles of bioethics and international human rights.

The hepatic lipid peroxidation, copper and fibrosis in cholestatic rats.

Hepatic lipid peroxidation was shown to be stimulated in the livers of cholestatic rats with increased hydroxyproline levels. In another group, cholestatic rats were fed with a copper-supplemented diet to increase hepatic copper levels. Although liver copper concentrations increased about 16-fold in copper supplemented cholestatic rats compared to normally fed cholestatic rats, no change was observed either in hepatic lipid peroxidation or in hydroxyproline levels.