Biomedical subjects
Publications and source records attributed to S Nishimura.
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The infusion model was used to investigate the resolution mechanism of vasogenic brain oedema. HRP dissolved in autoserum was infused into the white matter of cats. The infused protein in the oedema fluid seemed not only to be absorbed by pinocytosis or phagocytosis, as has been reported previously, but also to be quickly washed out via the perivascular space of the post-capillary venules. Smaller molecules such as HRP moved faster than serum albumin in these spaces after the infusion pump was turned off. Rapid flow of extracellular fluid via the perivascular space may play an important role on the resolution process of vasogenic brain oedema by accelerating diffusion.
Islet amyloid polypeptide is a 37 amino acid hormone-like peptide which is the major protein component of islet amyloid deposits commonly found in patients with Type 2 (non-insulin-dependent) diabetes mellitus. Recent studies indicate that a physiologically active form of this peptide appears to be carboxyamidated and secreted from the insulin-producing beta cell. In order to clarify the possible in vivo actions of islet amyloid polypeptide, we have studied the effects of synthesized islet amyloid polypeptide-amide on peripheral glucose utilization by performing hyperinsulinaemic euglycaemic glucose clamp studies on dogs. Exogenously administered islet amyloid polypeptide-amide (an infusion from 1.0 to 100 micrograms.kg-1.h-1, over 2 h) inhibited the insulin-stimulated glucose disposal rate in a dose dependent manner. Twenty-five micrograms.kg-1.h-1 of islet amyloid polypeptide-amide infused via a peripheral vein significantly lowered the glucose disposal rate by 20% (from 17.4 +/- 1.7 to 14.4 +/- 1.7 mg.kg-1.min-1, n = 5, p less than 0.01). These findings suggest that islet amyloid polypeptide-amide causes peripheral insulin resistance in vivo.
The purpose of the present study was to describe the clinical course of patients with Grade-5 ruptured aneurysms (WFNS grading). Among 250 consecutive cases of ruptured aneurysms, 60 Grade-5 patients were reviewed retrospectively, consisting of 24 males and 36 females with an average age of 58 years. Thirty-two patients were directly transferred to our clinic, while the remaining 28 were referred from other clinics. Duration from rupture to arrival at our clinic was within 1 hour in 25 cases and within 2 hours in 43 cases. Systolic blood pressure on admission was 186 mmHg on average. Obvious misdiagnoses by primary physicians were made in 7 cases. Ventricular drainage and clipping/trapping of the aneurysms were performed in 7 and 25 cases, respectively. Forty-nine patients died and the remaining 11 survived. One made a good recovery, 1 was moderately disabled, 8 severely disabled, and 1 in a vegetative state. The prognosis for Grade-5 patients is well known as being extremely poor, which also was the case in our series. Early referral and early surgical intervention have not changed this poor prognosis. Possible improvement of the outcome of this group might be expected by 1) public health and primary physician education on aneurysmal subarachnoid haemorrhage, and 2) control of blood pressure during referral.
We describe an infant with congenital pyloric atresia associated with junctional epidermolysis bullosa, which is now recognized as an autosomal recessive syndrome. Laparotomy revealed a membrane in the pyloric antrum. Clinical manifestations included intractable diarrhoea and malnutrition due to protein-losing gastroenteropathy. A satisfactory nutritional state could not be obtained during the clinical course and the child died.
These factors influence proliferation and differentiation in various cell types. Their effects on a clonal cell line (RPC-C2A) having high ALPase activity were examined by assay of [3H]-thymidine incorporation and ALPase activity. Neither factor (at a dose of 0.5 ng/ml) altered the shape of the pulp cells. DNA synthesis was not affected by transforming growth factor-beta either in growing cells or in those nearly confluent, but epidermal growth factor, in doses ranging from 0.5 to 10 ng/ml, stimulated the incorporation of [3H]-thymidine in nearly confluent cells. Both factors inhibited ALPase activity in a dose-dependent manner. Indomethacin did not affect this inhibition, suggesting that this effect of growth factors may not be mediated by prostaglandin synthesis. Inhibitory effects of ALPase antagonists (L-phenylalanine, L-homoarginine, levamisole) were not affected by transforming growth factor-beta. Thus epidermal growth factor stimulates DNA synthesis and both transforming growth factor-beta and epidermal growth factor inhibit ALPase activity of clonal rat pulp cells, suggesting that both factors may act as regulators of biological function, including cell differentiation, in pulp cells.
An aqueous solution of calf thymus DNA was irradiated by 60Co gamma-rays and modified nucleosides produced in DNA were analyzed by high-pressure liquid chromatography coupled with a photodiode array UV detector. A new product with UV absorption maxima at 230 nm and 280 nm was observed. The structure of this compound was proposed to be 5-formyldeoxyuridine (f5dU) based on the mass spectrum of its trimethylsilyl derivative (M+, m/z472) and the structure was confirmed by chemical synthesis. The yield of f5dU (2.4/10(4) dT/krad) in DNA was of roughly the same order as that of 8-hydroxydeoxyguanosine and 5-hydroxymethyldeoxyuridine. Free f5dU was mutagenic to Salmonella typhimurium strain TA102: therefore f5dU incorporated into DNA may induce mutations.
Normal RAS proteins play a key role of molecular switch in the transduction of the growth signal from extracellular to intracellular space. The state of the switch is "on" when GTP is bound and "off" when GDP is bound to the protein. The crystal structure of a complex between a nonhydrolyzable GTP analog and the catalytic domain of a RAS protein has been determined by a rotation-translation search method. The orientations and positions of four independent molecules have been determined using a single molecule as a probe in the search. The crystal structure reveals that the gamma phosphate of the GTP analog induces extensive conformational changes on two loop regions of the protein.
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Three Japanese patients with isolated growth hormone deficiency from two different families were shown to be homozygous for deletion of the structural gene for human growth hormone (hGH-I gene). These three patients had the same restriction fragment length polymorphism haplotypes. In patient No. 1, the growth rate initially responded well to pituitary human growth hormone, but growth rapidly ceased concomitantly with the development of high levels of anti-hGH antibodies. He again responded well to recombinant methionyl hGH and recombinant hGH without the methionine residue, even though having high hGH antibodies. Two siblings (Patients No. 2 and 3) showed a rather good response to pituitary hGH treatment without hGH antibodies ever being detected (the Israeli-type). hGH-I gene deletions may not necessarily result in hGH antibody formation. Heterogeneity has been observed in isolated hGH deficiency due to hGH-I gene deletion. hGH-I gene analysis should not be limited to patients with hGH antibody formation and subnormal growth responses to hGH therapy.
A cleavage of rat DNA with restriction endonuclease Taq I produced at least 8 discrete bands. One of the bands, 0.29 kilobase pairs (kb) long, was isolated and cloned in plasmid. The hybridization of this fragment to genomic DNA digested with Taq I showed 1.6 kb, 1.2 kb and 0.29 kb band in a smear hybridization signal. A repetition of the DNA sequence of this fragment was about 12,500 copies/haploid genome of both Buffalo and Sprague-Dawley rats by the Cot-hybridization analysis. Four independent clones of 0.29 kb Taq I fragment share high homology (97%).
Four patients with severe intraventricular hemorrhage (IVH) were treated using urokinase administered into the lateral ventricles via a ventricular drainage catheter. All patients were female and of ages ranging from 24 to 53 years. The primary diseases were hemorrhagic infarction, moyamoya disease, sinus thrombosis, and thalamic bleeding. Urokinase administration was initiated at 1.3 days average after occurrence of IVH and continued for 3.3 days average in doses of 12,000-96,000 IU per day. Average clot lysis times from IVH, as assessed by computed tomography, were 5.0 +/- 0.8, 5.0 +/- 1.4, and 6.0 +/- 0.8 days for the fourth, the third, and the lateral ventricles, respectively. All patients suffered from meningitis which was probably caused by urokinase administration through a ventricular catheter. However, this was successfully treated by changing the antibiotics. There was no general bleeding tendency or intraventricular rebleeding due to urokinase administration, and none of the ventricular catheters were obstructed by clots throughout the course. The final outcome was good recovery in two patients, severe disability in one, and persistent vegetative state in one. These results correlated well with the consciousness level seen before ventricular drainage in each patient. Consequently, we are convinced that urokinase administration can prevent the harmful effects of IVH and that urokinase is useful not only for lysing ventricular clots but also for maintaining the patency of the ventricular catheter, which is important for control of intracranial pressure in the acute stage of severe IVH.
The authors report a case of subarachnoid hemorrhage and spinal root injury caused by an acupuncture needle buried in the posterior neck about 30 years before onset. A 33-year-old female presented with sudden onset of severe occipital headaches. Plain x-ray films of the cervical spine revealed a fine gold needle, about 1.5 cm in length, between the C1 and C2 vertebrae. The needle was piercing the spinal nerve root through the dural vein, and was removed. Postoperatively, the pain exacerbated by neck movement disappeared.
Active oxygen species (AOS) such as O2- and H2O2 have been shown to be generated from both gas and tar phases of cigarette smoke and it has been suggested that they are involved in carcinogenesis due to cigarette smoking. Therefore, we investigated the effect of cigarette smoking on oxidative DNA damages in human peripheral blood cells using 8-hydroxydeoxy-guanosine (8-OH-dG) as a marker. From ten healthy male volunteers aged 20-22 years, 5 ml of blood was taken before and 10 minutes after smoking 2 cigarettes in 10 minutes. After lysis of blood cell membranes leukocyte DNA was isolated using a DNA extractor and 8-OH-dG levels were determined using high performance liquid chromatography (HPLC) with electrochemical detection. The mean levels of 8-OH-dG increased significantly (P less than 0.05) from 3.3 +/- 0.8/10(6) dG (mean +/- SD) to 5.1 +/- 2.5 after smoking. These results indicate that cigarette smoking induces oxidative DNA damage in peripheral blood cells in a relatively short time.
A new encircling clip made of a silicone tube has been designed for treating accidentally injured cerebral vessels. No special holders are necessary. This clip can be tailored depending on the shape of the injured vessel. The clip is a simple and effective tool for achieving complete hemostasis.
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The synthesis and biological properties of some 3-vinylthio- and 3-vinylthiomethylcephem derivatives are described. Both series possess potent antibacterial activity. Among them, 3-[(Z)-2-cyanovinylthiomethyl]cephem derivative was found to have an expanded antibacterial spectrum.
The synthesis and antibacterial activity of several 7 beta-[1-(2-aminothiazol-4-yl)-1-cyclopropanecarboxyamido]cep hem derivatives (1) are described. The structure-activity relationships of 1 are also presented.