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.

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.

[Problems encountered during natural disasters: a questionnaire study]. / Dogal afetler sirasinda karsilasilan sorunlar: bir anket çalismasi.

Human being has been encountering huge natural mass disasters since the dawn of existence. In the earthquake both Marmara region on August 17 1999 and Duzce region on November 12 1999, according to official records, 18.287 people were dead and 46.857 were injured. The purpose of this study is to get information by bilateral interviews with those who witnessed this big earthquake in different districts and to contribute in forming a prepared "disaster administration" consciousness for the prospective disasters, under the basis of these information. This study was made by interviewing with 262 people, 82 of whom witnessed the earthquake in the city of Yalova, 90 in Izmit, Bolu and Golcuk and 90 in Istanbul, used a questionnaire form consisted of multi choice and commentary questions. It is of very importance to diffuse educational programmes to increase social consciousness and sensibility about earthquake. Some projects to meet the basic requirements like communication, rescue, accommodation, nutrition and urgent medical support must be developed and embodied. Measures enabling to determine the identities of those who lose their lives in the earthquake must be determined and organized with the collaboration of forensic medical units.

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.

Effect of aluminum on the blood-brain barrier permeability in acute and chronically hyperglycemic rats.

This study examined the changes in blood-brain barrier (BBB) permeability following acute aluminum (Al) exposure during acute and chronic hyperglycemia in rats. Acute hyperglycemia was induced by intraperitoneal injection of glucose solution at 30 min after giving Al. Chronic hyperglycemia was made by an injection of alloxan monohydrate. BBB permeability was measured in the four regions of the brain at 1 h after administrating Al by spectrophotometric quantification of Evans blue (EB) dye. The extravasation of EB dye was significantly more extensive in the two regions of brain in the groups treated with Al, Al plus glucose, and alloxan plus Al than in the groups treated with saline, glucose, and alloxan alone (p < 0.05). Under acute and chronic hyperglycemia plus Al treatment, the BBB permeability to EB was significantly higher than that observed solely in Al-treated rats (p < 0.05). These data indicate that Al toxicity leads to an additional increase in BBB permeability, in which acute and chronic hyperglycemia potentiates the effects of Al to enhance BBB permeability to EB.

Effects of profound hypothermia on the blood-brain barrier permeability in acute and chronically ethanol treated rats.

This study examines the effects of profound hypothermia on the blood-brain barrier (BBB) permeability in ethanol administrated rats. Vascular permeability to intravenously injected Evans blue (EB) was quantitatively examined in the brain regions of rats. Rats were treated with ethanol acute and chronically. Rectal temperature of rats was dropped into 20+/-1 degrees C during profound hypothermia. Mean arterial blood pressure in both acute and chronic ethanol treatments plus hypothermia significantly dropped into low levels as well as in hypothermia alone (P<0.01). Hypothermia led to a significant increase in the content of EB dye in the brain regions of rats (P<0.05). Both acute and chronic ethanol treatments plus hypothermia did not lead to a significant increase in the BBB permeability against intravenously injected EB dye. We conclude that ethanol intake protects the BBB against the effects of hypothermia.

Analysis of gastrocnemius compound muscle action potential in rat after death: significance for the estimation of early postmortem interval.

The estimation of postmortem interval is of great importance in forensic medicine. Changes in the properties of excitable tissue provide another possible means by which the time of death can be estimated. This paper reports the monitorization of the compound action potentials recorded from gastrocnemius muscle by means of sciatic nerve stimulation in rats before and after death. The sciatic nerve was stimulated using rectangular impulses of 0.1ms duration and intensities ranged between 1 and 100mA while the rat was alive. Subsequently, the rat was killed by cervical dislocation. The similar measurement procedure was performed at the moment of death and every 5min after sequentially. There was a progressive decline in amplitude values that began 10min after death. The decrease in the amplitude of the compound muscle action potentials (CMAP) was most prominent especially when elicited with lower stimulus intensities. The mean area of the CMAPs also began to decrease beginning from 15min after death. Fifteen minutes after death, the motor latencies began to prolong. Thirty-five minutes after death, the decline in amplitude and area of mean CMAP was most prominent as the mean motor latency. At the 40th minute, most of the CMAPs were unelicitable. During the early postmortem interval, these amplitude, area and motor latency alterations decrease in the amplitude and area, prolongation of motor latency seems to be well correlated with each other and this was statistically significant. These findings are discussed as possible basis of a forensic method for postmortem interval estimation.

Questioning the psycho-socio-cultural factors that contribute to the cases of suicide attempts: an investigation.

Suicide attempts can be described to include all actions taken by an individual to end their life as a result of acute desperation. In parallel with the changes in the make-up of human societies both globally and in this country in recent years, suicide attempts are receiving attention in ever increasing proportions. The current study is aimed at investigating the psycho-socio-cultural factors that contribute to the known cases of suicide attempts. The study included 116 cases admitted to the Emergency Internal Medicine and Surgery Units of the University of Istanbul, Faculty of Medicine Hospital between 1 December 1998 and 31 May 1999. In only 47 cases, a 30-point questionnaire was used in several face-to-face interviews with the patients following the preparation of a clinical case study. In establishing the socio-demographic, socio-cultural and socio-economic attributes of each individual case, a range of contributing effective factors is questioned. Including the specific reasons for each suicide attempt, the emotional state of the individual prior to the suicide attempt, the type of suicide action chosen and reasons for this selection, immediate family structure, personal psychiatric antecedent, substance abuse. The results of our investigations are compared with the existing literature in a multi-faceted discussion.