PubMed Health⌕ Search

Biomedical subjects

H Sameshima

Publications and source records attributed to H Sameshima.

At least 19 recordsLinked to original sources
PubMed2004

Estimation of physiologic ability and surgical stress (E-PASS) for a surgical audit in elective digestive surgery.

BACKGROUND: This study was undertaken to establish an equation to estimate mortality with the use of the prediction scoring system designated as the Estimation of Physiologic Ability and Surgical Stress (E-PASS), and to evaluate the system's usefulness in defining quality of care by comparing it with the Physiologic and Operative Severity Score for the enUmeration for Mortality and morbidity (POSSUM) and Portsmouth-possum (P-POSSUM) scoring systems previously generated for surgical audit. METHODS: Patients (n=5212; group A) who underwent elective gastrointestinal surgery were analyzed to establish equations for estimated 30-day and in-hospital mortality rates. The usefulness of E-PASS was evaluated in another series of 1934 patients (group B) who underwent elective digestive surgery in 6 national hospitals. The ratio of observed to estimated mortality rates (OE ratio) of each hospital was defined as a measure of quality. RESULTS: In group A, 30-day and in-hospital mortality rates increased as the Comprehensive Risk Score (CRS) increased, providing equations for estimated mortality rates. There was an excellent correlation between the estimated and observed mortality rates in individual diseases: R=0.958, N=6, P=.0027 for in-hospital mortality; R=0.937, N=6, P=.0059 for 30-day mortality. In all patients of group B, the E-PASS system estimated the 30-day mortality rates by 0.63-fold (linear analysis), whereas the POSSUM score was 11.0-fold (exponential analysis). The E-PASS system estimated the in-hospital mortality rates by 1.2-fold (linear analysis), whereas the P-POSSUM score was 4.5-fold (linear analysis). The OE ratios for 30-day mortality among the 6 hospitals defined by E-PASS correlated well with those defined by POSSUM: R=0.996, N=6, P<.0001. Similarly, the OE ratios for in-hospital mortality defined by E-PASS were also highly correlated with those defined by P-POSSUM:(R=0.929, N=6, P=.0075. CONCLUSIONS: The E-PASS scoring system may be useful in defining surgical quality and may be more accurate than existing systems in evaluating elective digestive surgery.

Digestive System Surgical Procedures↗
PubMed2001

Evaluation of an Estimation of Physiologic Ability and Surgical Stress (E-PASS) scoring system to predict postoperative risk: a multicenter prospective study.

We previously reported generating a scoring system termed E-PASS that predicted postsurgical risk. This study was undertaken to evaluate the usefulness of this system. A consecutive series of 902 patients who underwent elective gastrointestinal operations in six national hospitals in Japan were prospectively assessed for a comprehensive risk score (CRS) of the E-PASS, which was compared with their postoperative course. The postoperative morbidity rates linearly increased as the CRS increased. The postoperative mortality rate was only 0.13%, when the CRS was below 0.5; however, it increased to 9.7% when the CRS ranged from 0.5 to <1.0, and to 26.9% when the CRS was > or =1.0. The CRS correlated significantly with the severity of postoperative complications (rs = 0.527, P < 0.0001) and the costs of hospital stay (rs = 0.810, P < 0.0001). When the CRS-adjusted mortality rate at the CRS of > or =0.5 was compared among the hospitals, it was related to the hospital volume of operations, being 44.2% at the volume of <100 cases per year, 20.6% at the range of 100-199 cases, and 8.6% at the volume of > or =200 cases. These results suggest that E-PASS may be useful for predicting postsurgical risk, estimating medical expense, and comparing surgical quality.

Adolescent↗
PubMed2001

Long-term magnesium sulfate treatment as protection against hypoxic-ischemic brain injury in seven-day-old rats.

OBJECTIVE: Our purpose was to study the effects of long-term treatment with magnesium sulfate on hypoxic-ischemic brain damage in newborn rats. STUDY DESIGN: Seven-day-old rat pups (n = 120) were exposed to unilateral carotid artery ligation and 2 hours of hypoxia (8% oxygen in 92% nitrogen). Neuronal loss was evaluated in 4 groups. The loading dose group (n = 25) received a bolus injection of 270 mg/kg magnesium sulfate intraperitoneally. The maintenance group (n = 26) received 3 days of continuous infusion of magnesium sulfate with a micro-osmotic pump at a rate of 72 mg/kg per hour. The loading dose-plus-maintenance group (n = 23) received both. The control group (n = 46) did not receive magnesium. Seven days after the injury the pups were killed and the brains were removed for analysis. Severity of neuronal loss was evaluated in the cerebral cortex and hippocampus and compared among groups by chi2 test. RESULTS: Cyst formation resulting from necrosis was significantly decreased in the maintenance group (15%) and loading dose-plus-maintenance group (9%) but not in the loading dose group (52%) relative to the control group (46%). Severity of neuronal loss in the cerebral cortex and the hippocampus was also significantly improved in the maintenance group and the loading dose-plus-maintenance group but not in the loading dose group. Mortality rates were not different among the groups. Magnesium ion concentrations at 24 hours were significantly decreased from the preinfusion value of 0.49 +/- 0.01 mmol/L in the control group (0.34 +/- 0.03 mmol/L) but remained within normal ranges in the maintenance group (0.46 +/- 0.02 mmol/L with a pump infusing 72 mg/kg per hour and 0.56 +/- 0.05 mmol/L with a pump infusing 24 mg/kg hour). There was an inverse relationship between the maintenance dose and neuronal loss but not between the maintenance dose and mortality rate. CONCLUSION: Long-term magnesium administration had neuroprotective effects against hypoxia-ischemia in newborn rats.

Animals↗
PubMed2001

Insulin-meal interval and short-term glucose fluctuation in tightly controlled gestational diabetes mellitus.

OBJECTIVE: To study the effect of two insulin-meal intervals on short-term glucose fluctuations in tightly controlled gestational diabetes mellitus (GDM). METHODS: We performed a prospective and paired study in 11 Japanese GDM women requiring insulin for good glycemic control during the third trimester. The women were subjected to test two insulin-meal intervals: 15 min and 30 min. Both regimens were examined in each patient in random order, 2 days apart. Blood glucose was measured by an automated glucose monitor every 2 min. Short-term glucose fluctuations of the two observations were analyzed by two-way ANOVA for repeated measurements with a post hoc t test (p < 0.05). Data were expressed as mean +/- SD. RESULTS: Daily glucose profiles of the two groups showed that their glycemic controls on the days of observation were good and that the two glucose profile curves were superimposable. A transient decrease in glucose (nadir 62 +/- 6 mg/dl) was observed at 6-10 min of meal ingestion in the 30-min regimen, which was significantly different from the glucose fluctuations during the 15-min regimen. The 2-h postprandial glucose levels were similar in both experiments. CONCLUSIONS: In women with tightly controlled GDM during the third trimester, insulin-meal intervals of 15 min are beneficial when compared with 30-min intervals, in that they avoid preprandial hypoglycemia without increasing 2-h postprandial hyperglycemia.

Adult↗
PubMed2001

[Toxicity study of cefmatilen hydrochloride hydrate (S-1090) (6)--Six-month repeated oral dose toxicity study in dogs].

A six-month repeated oral dose toxicity study of Cefmatilen hydrochloride hydrate (S-1090) at dose levels of 40, 100 and 250 mg potency/kg/day was conducted in male and female beagle dogs. No toxicologically significant changes were observed in general conditions of all animals. Reddish-brown feces (due to chelated products of S-1090 or its decomposition products with Fe3+ in the diet) were observed in all treated groups. Plasma irons showed a tendency to increase in the males and females of the 250 mg potency/kg group. However, as no changes suggesting anemia or hepatic injury were observed in this group, the change of plasma iron was considered to have no toxicological significance. No toxicologically significant changes were observed in other examination items. The plasma S-1090 concentrations increased in a manner less than dose-proportional. Based on the above results, the NOAEL of S-1090 was assessed to be 250 mg potency/kg/day.

Administration, Oral↗
PubMed2001

[Toxicity study of cefmatilen hydrochloride hydrate (S-1090) (5)--Six-month repeated oral dose toxicity study and supplement study in rats].

Cefmatilen hydrochloride hydrate (S-1090) was orally administered to rats at dose levels of 100, 300 and 1000 mg potency/kg once daily for 6 months. All the S-1090 treated groups showed soft feces, reddish-brown feces (due to chelated products of S-1090 or its decomposition products with Fe3+ in the diet), abdominal distention, increased food and water consumption, lower urine pH, and a decrease of white blood cells counts (except for males of the 100 mg potency/kg group). One male in the 300 mg potency/kg group showed mucous feces and marked decrease in body weight, and diet in the middle stage of the administration period. In necropsy of the survivors of all treated groups, marked cecal enlargement was noted. No remarkable changes were observed in the other examination items. From the early stage of the withdrawal period, animals in the 1000 mg potency/kg group showed again soft or mucous feces and a marked decrease in body weight. Of these animals, one male died and another male was sacrificed in a moribund state at about 2 weeks of the withdrawal period. Enterocolitis was observed in these cases. Almost all animals recovered within 3 weeks of withdrawal. A supplemental study of the 6-month toxicity study was conducted to examine the mechanisms of enterocolitis and the changes observable in the 100 or 300 mg potency/kg groups after drug withdrawal. As a reference, cefdinir (CFDN), an oral cephem antibiotic the same as S-1090, was added in the 1000 mg potency/kg group. No deaths occurred in any groups. Decreased intestinal flora were noted in all the groups treated with S-1090 or CFDN at the end of the dosing period. At 2 weeks of the withdrawal period, C. difficile and its D-1 toxin in the cecal contents were highly detected in the S-1090 300 and 1000 mg potency/kg groups and CFDN group. Inflammatory changes in the cecum and colon were observed in these groups. At 4 weeks of the withdrawal period, intestinal flora in the S-1090 groups almost returned to the condition before dosing, but those in the CFDN group were retained highly. Cecal D-1 toxin in the CFDN group was positive and higher than in the S-1090 groups. It was thus considered that the critical condition with enterocolitis resulted from C. difficile, which proliferated more rapidly than the other bacteria and D-1 toxin produced by this bacteria in the withdrawal period. Above changes were commonly observed in the CFDN group. The NOAEL of S-1090 was assessed to be 100 mg potency/kg/day which induced no enteritis.

Administration, Oral↗
PubMed2000

Early glycemic control reduces large-for-gestational-age infants in 250 Japanese gestational diabetes pregnancies.

Our objective was to test if tight glycemic control versus loose glycemic control in gestational diabetic patients and a gestational age of < 32 weeks influence fetal growth, fetal distress, and neonatal complication. We performed a retrospective study with 250 gestational diabetes mellitus in Japanese women. Two groups were categorized according to the timing at which good maternal glycemic control was attained at < 32 weeks and kept so until delivery (group 1) and > 32 weeks or never until delivery (group 2). In these two groups, neonatal growth (large-for-gestational age: LGA; appropriate- : AGA; and small- : SGA), neonatal complications (hypoglycemia, jaundice, polycythemia, and cumulative incidence), and incidence of fetal distress were compared. The chi2 test, unpaired t test, one-way analysis of variance (ANOVA) and multiple logistic regression analyses were used for statistical analyses. Maternal age, height, prepregnancy body mass index (BMI), gestational age at delivery were not different between the groups. In group 2 (> 32 weeks), LGA, macrosomia (> 4 kg), neonatal hypoglycemia was significantly increased compared with those in group 1. Incidence of SGA, fetal distress, and neonatal jaundice were not different between the groups. Multiple logistic regression analysis for LGA showed significant relation to timing of maternal glycemic control. We concluded that good glycemic control should be attained at < 32 weeks and maintained until delivery to reduce LGA infants and neonatal hypoglycemia in gestational diabetes mellitus. This management did not appear to decrease SGA infants or fetal distress.

Analysis of Variance↗
PubMed2000

Antepartum evaluation of monochorionic diamniotic (MD) twins; MD-twin score: a new scoring method for perinatal outcome.

OBJECTIVE: Our purpose was to establish a new scoring method to survey monochorionic diamniotic (MD) twins during antepartum periods. STUDY DESIGN: A retrospective study was performed regarding MD twins delivered between January 1992 and July 1996. Maternal and neonatal records were assessed for the following 5 perinatal variables; birth-weight discordance, amniotic-fluid discordance, hydrops fetalis, umbilical-cord insertion, and fetal-heart-rate monitoring. Each variable was coded as normal or abnormal and then assigned an arbitrary weight of 0 if normal and 1 if abnormal, yielding a range of scores from 0 (all normal) to 5 (all abnormal). The relationships between individual variables and their combinations and the outcome of pregnancy was determined. A poor pregnancy outcome consisted of intrauterine death, neonatal death, or neurological sequelae of at least one twin. The 5-variable combination was termed as the MD-twin score. A chi-square test and logistic regression analysis were used to determine statistical significance. RESULTS: There were 59 MD pregnancies, of which 13 pregnancies resulted in a poor outcome. The single variable that most likely contributed to a poor outcome was amniotic-fluid discordance. All 35 pregnancies with an MD-twin score of < or = 2 had a good outcome. There were 14 pregnancies with a score of 3, and 21% of them had a poor outcome. All of the pregnancies with a score of > or = 4 had a poor outcome. When we chose the MD-twin score of 3 as the critical point for a poor outcome, the likelihood ratio statistics became the highest of any single variable or any combination of variables. CONCLUSION: The MD-twin score predicted poor outcomes better than did any single variable or combination of variables.

Amniotic Fluid↗
PubMed2000

Fetal cardiovascular function during prolonged magnesium sulfate tocolysis.

The purpose of this study was to evaluate the fetal cardiovascular function during prolonged magnesium sulfate tocolysis. We performed a fetal ultrasonographic examination in 15 patients (Mg group) during magnesium sulfate tocolysis for the treatment of preterm labor. The maternal serum magnesium concentration was 5.7 +/- 0.5 mg/dl at the time of the examination. Sixteen fetuses in normal pregnancies at similar gestational ages were used as the control group. The fetal heart rate and the middle cerebral artery pulsatility index in the Mg group were lower than in the control group (p < 0.01). Fractional shortening (FS) of the right ventricle in the Mg group was lower (p < 0.01), while FS of the left ventricle was higher (p < 0.01) than in the controls. The calculated blood flow through the tricuspid orifice in the Mg group was lower than in the control group (p < 0.01). In contrast, the blood flow through the mitral orifice in the Mg group was higher than in the control group (p < 0.01). In conclusion, in spite of the fact that the right ventricular function is depressed, the fetus maintains its cardiac output during prolonged hypermagnesemia by increasing its left ventricular function. These results indicate the different fetal intracardiac and peripheral circulation, especially in the brain, from normal fetuses.

Adult↗
PubMed1999

Pretreatment with magnesium sulfate protects against hypoxic-ischemic brain injury but postasphyxial treatment worsens brain damage in seven-day-old rats.

OBJECTIVE: Our purpose was to study the neuroprotective effect of magnesium sulfate on hypoxicischemic brain damage and how the timing of magnesium administration changes its effect in the newborn rat. STUDY DESIGN: Seven-day-old rats (n = 91) were exposed to unilateral carotid artery ligation followed by 2 hours of hypoxia (8% oxygen in 92% nitrogen). Magnesium sulfate (270 mg/kg) was intraperitoneally administered 30 minutes before (pretreatment) or 30 minutes after (posttreatment) the 2 hours of hypoxia. In each experiment equivalent amounts of saline solution were administered as controls. Seven days after the injury the rats were killed and the brains were removed for histologic study with hematoxylin and eosin staining. The severity of brain atrophy and neuronal damage was evaluated in the cerebral cortex and hippocampus and compared by chi2 test between the magnesium group and the controls. RESULTS: Ionized magnesium concentrations were significantly increased from 0.52 +/- 0.02 mmol/L to 1.38 +/- 0.07 mmol/L at 0.5 hour after injection and thereafter gradually decreased to 0.73 +/- 0.07 mmol/L at 3.5 hours. Magnesium significantly reduced the incidence of weight loss (0% in magnesium vs 29% in controls) and protected the cerebral cortex from neuronal loss (the incidence of normal, mild, moderate, and severe neuronal loss was 48%, 29%, 5%, and 19% in magnesium and 30%, 5%, 25%, and 40% in controls, respectively) in the pretreatment group. In the posttreatment group magnesium caused increased neuronal damage compared with the controls. CONCLUSION: Magnesium sulfate has neuroprotective effects against hypoxia-ischemia. This effect is restricted to the pretreatment group in which magnesium sulfate is administered before the insult.

Animals↗
PubMed1999

Heat shock protein 72 expression and microtubule-associated protein 2 disappearance after hypoxia-ischemia in the developing rat brain.

OBJECTIVE: This study was intended to investigate the temporal changes in heat shock protein 72 expression and microtubule-associated protein 2 disappearance in rat brain at 2 different ages after hypoxic-ischemic insult. STUDY DESIGN: Both 5-day-old and 14-day-old Wistar rats were subjected to unilateral common carotid artery ligation and hypoxia in 8% oxygen for 2 hours at 33 degrees C. Brain sections were examined sequentially for heat shock protein 72 expression at 0.5, 3, 6, 12, 24, 48, and 72 hours of recovery after hypoxia-ischemia and for microtubule-associated protein 2 disappearance at 0, 24, 48, and 72 hours of recovery and at 7 days of recovery after hypoxia-ischemia. Results of immunohistochemical staining for heat shock protein 72 and microtubule-associated protein 2 were used as markers for detection of early hypoxic-ischemic brain damage. Permanent neuronal damage was assessed with hematoxylin and eosin staining at 7 days after hypoxia. RESULTS: In 5-day-old rats microtubule-associated protein 2 expression was lost as early as 0 hours after hypoxia-ischemia in the cerebral cortex and hippocampus, with a peak at 48 hours after which expression recovered. Expression of heat shock protein 72 was detected in the ligated hemisphere at 0.5 hours after hypoxia-ischemia and peaked at 6 to 24 hours of recovery. In 14-day-old rats microtubule-associated protein 2 was stained in the cortex at 0 hours after hypoxia-ischemia but gradually disappeared in the cerebral cortex and hippocampus after 24 hours of recovery. The expression of heat shock protein 72 was not detected by 6 hours of recovery in the cerebral cortex and by 3 to 12 hours of recovery in the hippocampus, but heat shock protein 72 was persistently expressed in the cortex and hippocampus after 48 hours of recovery. Neuronal damage was significantly less in 5-day-old rats than in 14-day-old rats. CONCLUSION: In 5-day-old rats hypoxia-ischemia causes earlier changes in heat shock protein 72 and microtubule-associated protein 2 immunostaining results and causes less severe brain damage than in 14-day-old rats.

Aging↗
PubMed1999

Intracranial haemorrhage as a cause of maternal mortality during 1991-1992 in Japan: a report of the Confidential Inquiry into Maternal Deaths Research Group in Japan.

OBJECTIVE: To determine the causes of maternal deaths by intracranial haemorrhage in Japan. DESIGN: Retrospective analysis of records relating to maternal deaths in 1991 and 1992. SAMPLES: Two hundred and thirty maternal deaths, including 25 cases of primary intracranial haemorrhage and two cases with secondary bleeding. METHODS: Attending doctors were interviewed and completed a 600-item data collection instrument for each maternal death. An expert committee reviewed the data for each death to determine whether the maternal deaths could have been prevented. MAIN OUTCOME MEASURES: Preventability of maternal death from intracranial haemorrhage treated in obstetric and emergency services in Japan. RESULTS: Half of the primary intracranial haemorrhages occurred during pregnancy, 20% during labour, and 30% in the postnatal period. Neurosurgeons considered that there were only three women in whom surgical drainage was indicated. The committee determined that there was only one maternal death which had a > or = 70% of being prevented. After detailed discussion of each case, 60% of the women (15/25) may have been saved by earlier and more intensive medical intervention. CONCLUSIONS: These findings suggest that detailed history taking and early diagnosis of intracranial haemorrhage would be helpful. Regionalisation of obstetric emergency systems are necessary to reduce maternal deaths in Japan due to intracranial haemorrhage.

Adult↗
PubMed1999

[Clinicobacteriological studies on the nine cases with upper genital tract Mycoplasma hominis infection].

Clinicobacteriological characteristics of nine cases isolated Mycoplasma hominis from the genital tract were studied, and the following results were obtained: elevation of IgG antibodies to M. hominis was measured by ELISA in all cases, but in the MI method only one case showed an elevation of metabolic inhibitory antibody. Convalescent sera from seven patients showed additional and high density bands which were not recognized by acute phase sera in immunoblotting. It was thought that in two patients M. hominis was a causal bacteria for pelvic inflammatory disease (PID). In three cases, it was suggested that M. hominis was related to a premature delivery and idiopathic labor. As infectious symptoms, two patients had body temperatures of more than 38 degrees C but other cases showed 37-37.8 degrees C. Though all cases showed an elevation of CRP, six elevations were slight. As a medication beta-lactam agents were administrated, but their efficacy was not recognized. Furthermore, two patients showed spontaneous recovery in spite of improper antimicrobial agents administration or drainage combined with antimicrobial agents. From the above results. It was thought that M. hominis played a causative role in upper genital tract infection.

Adult↗
PubMed1999

[Comparison of the effect of rapid infusion of lactated and that of acetated Ringer's solutions on maternal and fetal metabolism and acid-base balance].

The maternal and neonatal metabolism and acid-base balance were investigated in 20 parturients undergoing combined spinal and epidural anesthesia for cesarean delivery. Patients received intravenous infusion at a rate of either 25 ml.kg-1.h-1 of lactated (LR group, n = 10) or acetated (AR group, n = 10) Ringer's solution before anesthesia, to prevent hypotension during anesthesia. We obtained venous blood samples as follows; maternal control before anesthesia, maternal sample A after the infusion, umbilical sample B, and neonatal pedal sample C 5 h after birth, and determined lactate, pyruvate, bicarbonate, and base excess concentrations, and pH in each sample. In sample A, the lactate level was significantly higher and base excess level was significantly lower in the LR group than in the AR group. The pH of sample A and B was significantly higher in the AR group than in the LR group. However, no differences in all parameters of sample C between the two groups were observed. These results demonstrated that acetated Ringer's solution is better than lactated Ringer's solution in rapid infusion before cesarean section because of the correction of neonatal lactic acidosis.

Acid-Base Equilibrium↗
PubMed1999

Echocardiographic findings of pulmonary atresia or critical pulmonary stenosis and intact ventricular septum in utero.

BACKGROUND: Neonates with right ventricular outflow obstruction and intact ventricular septum show serious hemodynamic problems, such as severe hypoxemia, congestive heart failure due to massive tricuspid regurgitation, respiratory distress related to huge pulmonary hypoplasia or ventricular dysfunction due to right ventricle-coronary communication. Recent advances in fetal diagnosis include many cases of in utero diagnosis of pulmonary atresia or critical pulmonary stenosis and intact ventricular septum. METHOD: Among the fetuses examined from April 1994 to March 1998, five fetuses were found with pulmonary atresia (PA) or critical pulmonary stenosis (CPS). Fetal echocardiograms were reviewed to elucidate the accuracy of fetal information and the efficacy of fetal diagnosis in the perinatal management of patient with CPS or PA and intact ventricular septum. RESULTS: The five cases were divided into two groups: two with a very small right ventricle (group 1) and three with a tripartite right ventricle (group 2). Fetal cardiomegaly and right atrial dilatation were prominent in group 2, whereas cardiac sizes were normal in group 1. Serial fetal examination in one group 2 fetus revealed developing right ventricular hypertrophy in utero. All group 2 cases showed massive tricuspid regurgitation (TR). Estimated right ventricular pressures from TR always exceeded the systemic blood pressures of gestational age-matched neonates. Reversed flow through the ductus arteriosus was recorded in both groups and ductus-dependent pulmonary circulation after birth was anticipated. Patency of both tricuspid and pulmonary valves was difficult to recognize in utero, as was right ventricle-coronary artery communication. Four of the five cases were maternally transported and survived palliative and/or definitive intervention. One fetus with chromosomal abnormality was observed without intervention during infancy and received palliative surgery when she was two years old. CONCLUSION: Fetal hemodynamic information was useful for making decisions not only after birth, but also in utero, and may eventually result in improving the prognosis of babies with PA/CPS. Serial observation of the fetuses with PA/CPS may also suggest the possible pathogenesis of PA/CPS in utero.

Echocardiography↗
PubMed1998

Hypoxic-ischemic tolerance phenomenon observed in neonatal rat brain.

OBJECTIVE: Our purpose was to determine whether hypoxic-ischemic brain damage would be protected against by advance conditioning of the animal with 4 hours of hypoxic exposure. STUDY DESIGN: Neonatal rats were exposed on postnatal day 7 to (1) 4 hours of hypoxia with 8% oxygen (preconditioning hypoxic group) or (2) 4 hours of normoxia (sham-preconditioning group). At 24 hours after the conditioning, rats from both groups were exposed to left carotid artery ligation followed by 2 hours of hypoxia (8% oxygen/92% nitrogen). All the rats were killed 1 week after hypoxia-ischemia, and their brains were extracted for histologic study. RESULTS: Two types of brain damage were histologically observed at 1 week after hypoxia-ischemia in both groups: (1) generalized infarction in the ligated hemisphere and (2) predominant neuronal loss in the hippocampal region. The total incidence of brain damage was significantly decreased in the preconditioning hypoxic group (10/24 rats, 41.7%) compared with the sham-preconditioning hypoxic group (17/22 rats, 77.3%; P < .05). CONCLUSION: Our results show that the hypoxic-ischemic tolerance phenomenon may be induced in the hypoxic-ischemic brain damage model by conditioning the animal before the insult with 4 hours of hypoxic exposure.

Animals↗
PubMed1998

Effects of 4 hours magnesium sulfate infusion on fetal heart rate variability and reactivity in a goat model.

Effects of magnesium sulfate were investigated on fetal heart rate (FHR) baseline, variability, and reactivity in goats. Six chronically catheterized fetuses of Japanese Saanen goat at 125 to 130 days' gestation (term = 147 days) were used. Magnesium sulfate was directly infused to the fetuses. Short-term variability and long-term variability were obtained according to Huey et al. The baseline, reactivity, short-term variability and long-term variability of the FHR were compared between those receiving magnesium sulfate infusions and those receiving vehicle infusions without magnesium sulfate for 4 hr. Two-way analysis of variance (ANOVA) and Duncan's multiple range test was applied for statistical significance. Four hours magnesium sulfate infusion significantly increased fetal plasma concentration of magnesium from 2.4-6.6 mg/dL, without significant changes in fetal respiratory gases and pH values. The baseline FHR was significantly decreased by magnesium infusion compared with that receiving vehicle infusion. The incidence of acceleration, short-term variability, and long-term variability during the fourth hour of magnesium infusion was also significantly decreased compared to a controlled infusion. The time spent by high amplitude phase of short-term variability and that of long-term variability were also significantly reduced. Significant correlation was obtained between the magnesium concentration and incidence of acceleration at fourth hour of magnesium infusion. Four hours infusion of magnesium sulfate significantly decreases baseline FHR, short-term variability, long-term variability, and reactivity in fetal goats at 0.85 gestation.

Animals↗