Beneficial effect of tetrahydrobiopterin on the survival of rats exposed to hepatic ischemia-reperfusion injury

INTRODUCTION

The protective role of nitric oxide (NO) against hepatic ischemia-reperfusion (I/R) injury remains controversial. In this study we investigated the effect of tetrahydrobiopterin (BH4) on the survival of rats exposed to an hepatic I/R injury.

METHODS

The rats were subjected to 100 minutes of 70% hepatic ischemia 30 minutes after administration of BH4 or saline. A specific inducible NO synthase (iNOS) blocker, 1400W, was used to evaluate endogenous iNOS. NOS protein measured the histological appearance of the liver by Western blotting, and survival was evaluated after reperfusion.

RESULTS

The 1-week survival rate was 60% among the BH4 group and 10% for the saline group. The serum ALT and bilirubin values in the BH4 group were significantly lower than the saline group. Histological examination of the liver revealed only a small necrotic area in the BH4 group as opposed to massive necrosis and cell infiltration in the saline group. Injection of 1400W significantly decreased the prolongation of survival produced by BH4.

CONCLUSIONS

BH4 significantly improved the survival rate, the histological findings, and the liver function, thereby reducing liver failure. Western blotting showed a higher level of iNOS protein in the BH4 group than the saline group, 1400W suppressed this effect of BH4. Taken together, these observations suggest that NO derived from reactions driven by BH4-induced iNOS exerts a protective effect against reperfusion injury.

Central facial weakness due to medial medullary infarction: the course of facial corticobulbar fibres

Two patients are reported with contralateral hemiparesis including a face of supranuclear type, caused by an infarct of the unilateral ventromedial part of the upper medulla. Data from these patients support the hypothesis that part of the corticobulbar fibres supplying the lower facial muscles descend ipsilaterally in the ventromedial part of the upper medulla and then, after decussation, ascend rostrally to the contralateral facial nucleus.

[Central facial weakness due to medullary pyramidal infarction; a case report]

We reported a hypertensive 40-year-old man who developed sudden right hemiparesis, deep sensory disturbance, left hypoglossal nerve palsy, and mild right central facial weakness. MRI of the brain showed an infarct located in the left upper medullary pyramid. Course and connection of the corticobulbar pathway are not well known in human. Recently Cavazos (1996) described a hypothesis that some facial corticobulbar fibers descend caudally ipsilaterally as low as the upper medulla, making a loop before decussating and ascending to the contralateral facial nucleus Contralateral central facial weakness may result from interruption of these descending fibers.

[Favorable prognosis in a case of recurrent cerebral infarctions caused by chronic disseminated intravascular coagulation due to ovarian carcinoma]

We report a 53-year-old woman who developed a cerebral infarction in the left middle cerebral artery area. Although she did not have a hemorrhagic tendency, the results of her examination showed a chronic disseminated intravascular coagulation (DIC) and a left ovarian carcinoma. Gabexate mesilate (FOY) and nafamostat mesilate (FUT) were not effective for her DIC. One month after admission, she had another cerebral infarction in the right posterior cerebral artery area. She was treated by heparin sodium and her chronic DIC improved. Then, she was operated on for ovarian carcinoma; the histologic finding was clear cell adenocarcinoma. No recurrence of DIC nor cerebral infarction was observed postoperatively. Patients with cerebral infarctions caused by chronic DIC due to ovarian carcinoma have been reported in the literature, but few patients had a favorable prognosis such as the present case. Heparin therapy appears to be the treatment of choice for chronic DIC rather than FOY or FUT, if there is no hemorrhagic tendency. When a patient with DIC develops cerebral infarction, one should always investigate for possible malignant tumors.

Effects of serotonin on the release of thyrotropin-releasing hormone from the rat retina in vitro

Effects of serotonin on the release of thyrotropin-releasing hormone (TRH) from the rat retina were studied in vitro. The retina was incubated in medium 199 (pH 7.4) with 1.0 mg/ml of bacitracin and 100 micrograms/ml of ascorbic acid (medium) for 20 min. The amount of TRH release into the medium was measured by radioimmunoassay. The TRH release from the rat retina was inhibited significantly in a dose-related manner with the addition of serotonin and enhanced with cyproheptadine. The inhibitory effect of serotonin on TRH release from the retina was blocked with the addition of cyproheptadine. The elution profile of methanol extract of the rat retina was identical to that of synthetic TRH. The findings suggest that the serotonergic system inhibits TRH release from the rat retina in vitro.

[Clinical features of anterior inferior cerebellar artery territory infarcts--a study of ten patients]

Clinical features of the anterior inferior cerebellar artery (AICA) territory infarcts were investigated in ten patients, ranging in age from 38 to 76 years. In all patients, there were MR images of infarction located in the area supplied by the AICA. The lesion was on the left side in 6 patients and right side in 4. The lesion of brain stem including the middle cerebellar peduncle was found in 7 patients and that extended to the cerebellum was in 3 patients. The main ipsilateral neurological signs were the VII and VIII cranial nerves palsy and cerebellar ataxia. The V and VI cranial nerves palsy. Horner's syndrome, and dysphagia were also present. The main contralateral sign was superficial sensory disturbance, but no hemiplegia. The underlying pathology included chiefly hyperlipidemia, hypertension, and diabetes mellitus. Cerebral angiography was performed in 8 patients, most of which was observed severe arteriosclerosis suggesting poor hemodynamics in the vertebral and basilar arteries. The prognosis was relatively good, but the VII, VIII, and V cranial nerves palsy and contralateral superficial sensory disturbance remained as the sequelae. As mentioned above, there were various neurological findings and MR images in AICA territory infarcts. Especially there were some patients whose lesion extended to the upper medulla and neurological findings were similar to the Wallenberg syndrome. It is important that one investigates not only axial slices but also coronal slices of MR image to estimate the extension of AICA territory infarct.

Serum hyaluronic acid and interleukin-6 as possible markers of carpal tunnel syndrome in chronic hemodialysis patients

To elucidate the precise mechanism of carpal tunnel syndrome (CTS), serum hyaluronic acid (HA), interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha) were measured in 71 chronic hemodialysis patients with or without CTS and/or shoulder pain. Patients were divided into two groups: Group 1 (n = 40) was the control group, and Group 2 (n = 31) patients had carpal tunnel syndrome, shoulder pain, or both. None of the patients had liver disease, rheumatoid arthritis, other inflammatory disease, or cancer. Serum HA concentrations in Groups 1 and 2 were 106.0 +/- 77.5 and 442.6 +/- 564.7 ng/dl (mean +/- SD), respectively. The difference between the groups was significant (p < 0.01). The serum concentrations of IL-6 in Group 1 were significantly lower than in Group 2 (p < 0.05); however, there was no significant difference in serum IL-1 beta and TNF-alpha levels. The mechanisms regulating in vivo synthesis of HA was obscure; however, in vitro studies suggest that inflammatory cytokines may stimulate an increased production of HA. In this study, CTS might be associated with increased serum concentrations of HA, and HA production might be mediated by IL-6.