Optimal perfusion flow rate for the brain during deep hypothermic cardiopulmonary bypass at 20 degrees C. An experimental study

The relationship between the perfusion flow rate and cerebral oxygen consumption during deep hypothermic cardiopulmonary bypass at 20 degrees C was investigated in dogs. In 10 dogs the perfusion flow rate was decreased in steps from 100 to 60, 30, and 15 ml/kg/min every 30 minutes. Although cerebral blood flow decreased as perfusion flow rate decreased, the ratio of cerebral blood flow to the perfusion flow rate increased significantly (p less than 0.05) at a perfusion flow rate of 15 ml/kg/min compared to that at a perfusion flow rate of 100 or 60 ml/kg/min. The arterial-sagittal sinus blood oxygen content difference increased as perfusion flow rate decreased. Consequently, cerebral oxygen consumption did not vary significantly at perfusion flow rates of 100 (0.48 +/- 0.10), 60 (0.43 +/- 0.14), and 30 ml/kg/min (0.44 +/- 0.12 ml/100 gm/min), and it decreased significantly to 0.31 +/- 0.22 ml/100 gm/min at a perfusion flow rate of 15 ml/kg/min. In five dogs the perfusion flow rate was decreased in one step from 100 to 15 ml/kg/min, and after 60 minutes' perfusion at a perfusion flow rate of 15 ml/kg/min, the perfusion flow rate was returned to 100 ml/kg/min. Cerebral oxygen consumption decreased significantly during 60 minutes' perfusion at a perfusion flow rate of 15 ml/kg/min and did not return to its initial value after the perfusion flow rate was returned to 100 ml/kg/min. These data indicate that the optimal perfusion flow rate for the brain during deep hypothermic cardiopulmonary bypass at 20 degrees C appears to be 30 ml/kg/min, with a possible oxygen debt in the brain resulting in anaerobic metabolism if the perfusion flow rate is kept at 15 ml/kg/min or less.     

The long-term results of meniscus transplantation for articular cartilage defects in the knee joint

The purpose of this study was to examine the long-term clinical results of meniscus transplantation for articular cartilage defects in the knee joint. The type of study was case series. From October 1990 to June 1995, eight cases underwent allogenic or autogenic meniscus transplantations for articular cartilage defects, and seven cases were available for follow-up evaluations. The age at surgery ranged from 14 to 42 years of age (average 22.5). In one case, transplantation of tissue-engineered cartilage was performed due to pain 5 years after surgery. The other six cases were followed up for 8–13 years (average 10.1). The size of the cartilage defect ranged from 1.0 to 6.3 cm² (average 2.8 cm²). Patients were evaluated with the Lysholm score and MR images. We also performed arthroscopic examinations in three cases at the final evaluation. This study leads to the conclusion that meniscus transplantation for articular cartilage damage is not comparable to autologous chondrocyte transplantation. Two cases showed a good clinical outcome but the tissue remained as fibrocartilage tissue in the long-term.     

Clinical evaluation of midazolam as an anesthetic for geriatric patients and patients with hepatic dysfunction

This study evaluated the usefulness of midazolam in inducing a anesthetic state in 60 patients who underwent surgery under general anesthesia. The patients were divided into 3 groups; a geriatric group, a hepatic dysfunction group, and a control group (adults without complications). To induce sleep 0.15 mg.kg-1 or 0.2 mg.kg-1 of midazolam was administered intravenously to all three groups. After the administration of midazolam, the mean time for obtaining absence of response to calling name and absence of ciliary reflex were not significantly different in the three groups. The pulse rate and respiratory rate also did not change remarkably. But significant decreases were observed in the systolic blood pressure and tidal volume in all three groups. However, they were not significantly different among the three groups. These results indicate that midazolam is a useful drug for inducing anesthetic state in geriatric patients and patients with hepatic dysfunction.     

A case of a rare anomaly of the common bile duct associated with an abnormal arrangement of the pancreaticobiliary ductal union

A 39 year-old Japanese female patient with a duplication of the distal portion of the common bile duct is presented herein. Moreover, an abnormal arrangement of the pancreaticobiliary ductal union, congenital biliary dilatation and carcinoma of the gallbladder were all demonstrated by cholangiographic and endoscopical studies. The patient underwent radical surgery for advanced adenosquamous carcinoma of the gallbladder, and her postoperative course was satisfactory. A reflux of pancreatic juice into the bile duct was demonstrated, but it was eliminated and considered to be a contributory etiologic factor of the gallbladder carcinoma.     

Annulo-aortic ectasia with DeBakey type II dissecting aneurysm in Gaucher's disease

Annulo-aortic ectasia is an extremely rare complication of Gaucher's disease. We report successful surgery in a patient with Gaucher's disease complicated by annulo-aortic ectasia and aortic dissection. Cabrol's operation was accomplished without bleeding or sternal adaptation problems.     

Effect of midazolam as a premedicant

A new benzodiazepine-type drug, midazolam, was administered intramuscularly as a premedicant to 155 patients aged from 16 to 81 years with ASA status 1 or 2. The hypnotic action and the effect on the upper airway tract of midazolam were evaluated. Hypnosis appeared 5 minutes after the administration of midazolam, reached its plateau after 20 minutes and started to decline after 30 minutes. The hypnotic effect showed dose-dependent increase in doses ranging from 0.05 to 0.20 mg.kg-1. No age-dependent differences in hypnosis were observed except for teenage group which showed stronger hypnosis than the other age groups. There was no problem on the upper airway tract for all age groups at the dosage of 0.05 mg.kg-1, but in the patients over 40 years increasing dosage tended to obstruct the upper airway tract. Along with the appearance of hypnosis, cough and breath holding, suggesting retention and aspiration of saliva, were observed. The appropriate dosage of midazolam for premedication was considered to be 0.05 mg.kg-1.     

An immunocytochemical demonstration of calcineurin in human nerve cell tumors. A comparison with neuron-specific enolase and glial fibrillary acidic protein

Human central and peripheral nerve cell tumors were examined in detail using antibodies to calcineurin, glial fibrillary acidic protein (GFAP) and neuron-specific enolase (NSE). Forty-eight formalin-fixed and paraffin-embedded specimens of human neuronal tumors, including 27 medulloblastomas, were examined. Calcineurin-positive cells were found in all peripheral nerve cell tumors and the two gangliogliomas, whereas 20 of the 27 medulloblastomas and one of the two cerebral neuroblastomas did not contain calcineurin-positive cells. Differentiation of cells along the neuronal lines was positively correlated with calcineurin immunoreactivity. NSE-positive cells were found in all of the tumors with the exception of the one cerebral neuroblastoma. NSE immunoreactivity was not invariably consistent with calcineurin immunoreactivity and non-neuronal cells were often positive. Calcineurin-positive cells were all devoid of GFAP, but NSE-positive cells expressed GFAP in some tumors. GFAP-immunoreactive cells were found only in central nerve cell tumors, and not in peripheral tumors. In addition, GFAP-positive cells in some tumors such as retinoblastoma and medulloblastoma morphologically revealed not only neoplastic but also reactive astrocytic features.     

Effects of zinc and other divalent metals on deoxyribonucleic acid binding and hormone-binding activity of human alpha 1 thyroid hormone receptor expressed in Escherichia coli

Full-length human thyroid hormone receptor alpha 1 (hTR alpha 1) was expressed in Escherichia coli using a T7 expression system. While present in large amounts, the receptor was highly enriched in the insoluble fraction after cell lysis. We describe here the successful solubilization and refolding of the expressed receptor in a functional form in the presence of Zn2+. Using a DNA-cellulose binding assay and gel shift assay, we found that treatment of expressed receptor with 1 mM EDTA in the denaturing agent (5 M guanidine-HCl) results in the formation of aporeceptor that does not specifically recognize target DNA, while it does retain T3-binding activity. This aporeceptor recovered DNA-binding activity by adding Zn2+ during refolding. Zinc-induced restoration of DNA-binding activity occurred in a dose- and time-dependent manner. Moreover, once recovered, this DNA-binding activity persisted without Zn2+, even in the presence of 1 mM EDTA. These data indicate that the hTR alpha 1 molecule has a high affinity for Zn2+, and this metal coordination is essential for proper folding of TR protein into its native active structure.