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Biomedical subjects

S Yamazaki

Publications and source records attributed to S Yamazaki.

At least 487 records · Page 27Linked to original sources
PubMed1987

Antitoxic immunity of the population against diphtheria in Singapore.

A serological study to evaluate the efficacy of the diphtheria immunisation programme in Singapore based on sera collected from 425 healthy persons between 6 months and 40+ years of age showed that 94.6% of the population surveyed possessed protective neutralising antitoxin (greater than or equal to 0.01 IU/ml). No sex or ethnic difference was noted. The most suspectible age-group was adults above 40 years of age in which 14.3% had no protective antitoxic immunity against diphtheria (less than 0.01 IU/ml). The geometric mean titre was generally high with sharp anamnestic type of secondary response elicited by periodic boosters administered. The survey confirmed the efficacy of the childhood immunisation programme which extended from 3 months to 15+ years of age, in maintaining a high level of herd immunity of the population right into adulthood. Further extension of the programme to include routine revaccination of adults was not considered necessary.

Adolescent↗
PubMed1987

[Melanosis of choroid plexus papilloma of the lateral ventricle: a case report].

A case of pigmented, well differentiated, choroid plexus papilloma is reported. A 45-year-old man came to our hospital complaining of attacks of vertigo and nausea. Skull X-ray films and CT scan demonstrated a calcified tumor in the left middle fossa. Tumor removal was done, and it was found that the tumor occupied the inferior horn of the left lateral ventricle. Histological examination revealed well differentiated choroid plexus papilloma containing various shaped pigment granules in the cytoplasm. The pigment granules in the tumor cells were stained black by Fontana-Masson method for melanin. The stain was negative in a section subjected to oxidative bleach. Granules were PAS-positive and autofluorescence. Therefore, the pigment granules had properties of both melanin and lipofuscin. In the electron microscopic study the ultrastructural appearance of the pigment was similar to that of neuromelanin, but not to that of pre-melanosome of neural crest origin. The pigment in this case seemed to be formed by "melanization" of lipofuscin as Barden's theory of pseudo-peroxidation. There are several case reports of pigmented choroid plexus carcinoma. However, no case of pigmented, well differentiated choroid plexus papilloma has, so far, been reported.

Cerebral Ventricle Neoplasms↗
PubMed1987

Safety of hemihepatic vascular occlusion during resection of the liver.

To minimize both intraoperative bleeding and circulatory and biochemical disturbances due to the interruption of blood flow to the liver, we developed a technique for selective, mostly unilobar, control of the hilar vessels to the liver called hemihepatic vascular occlusion. One hundred and fifty-three patients who underwent hepatic resection were divided into four groups with and without cirrhosis of the liver and with and without hemihepatic vascular occlusion which was limited to 30 minutes followed by five minutes of perfusion, which was repeated if necessary. This technique reduced the intraoperative blood loss and the postoperative hyperbilirubinemia significantly but did not produce larger postoperative change of transaminases or lactic dehydrogenase serum levels when compared with similar resections without vascular control.

Bilirubin↗
PubMed1986

[Aluminum associated bone disease in patients undergoing long-term hemodialysis].

The widespread clinical use of hemodialysis has prolonged the survival of a vast number of uremic patients, but it has also yielded some problems including renal osteodystrophy. Recently, it has become well known that the clinical use of active vitamin D metabolites is effective in many patients with renal osteodystrophy. However, there are many patients with bone diseases resistant to such treatment. Several lines of evidences implicate aluminum as one of the causal factors in the production of such diseases. We recently found 20 patients with bone diseases associated with the deposition of aluminum in front of active calcification in the bone. All of them were undergoing maintenance hemodialysis with softened water thrice weekly and taking aluminum containing antacids and 1 alpha-(OH)D3. The age of the patients ranged between 30 y.o. and 62 y.o. (46.5 +/- 9.0, mean +/- s.d.). All of them had severe bone pain and 8 of them had bone fractures. Bone X-ray, bone scintigraphy, serum Ca, P, ALP, serum aluminum and bone histology were examined. Based on the bone histology, they were classified into four types; inactive type (9), osteomalacia type (6), mild type (4) and mixed type (1). There were no significant differences among each group concerning serum values of Ca, P and aluminum. Serum value of ALP tended to be high in the osteomalacia type, and that of c-PTH was significantly low in the inactive type compared with the other types. Our finding suggest that aluminum associated bone disease is not so rare in Japan and show that the diagnosis of this disease should be made histologically and that clinical and blood chemical features are not reliable for the diagnosis of aluminum associated bone disease in hemodialysis patients.

Adult↗
PubMed1986

Evolution of enterovirus 70 in nature: all isolates were recently derived from a common ancestor.

The data of large RNase T1-resistant oligonucleotide mapping of enterovirus 70 (EV 70) previously reported (Takeda et al., Virology 134, 375-388, 1984) were subjected to further genetical analysis to estimate the evolutionary rate of genome RNA of EV 70 and to clarify the phylogenetic relationship among isolates. A proportion of common spots between strains decreased as the year elapsed and eventually, only seven spots were common to all the 16 isolates tested, indicating that the substitution is scattered throughout the genome. On the other hand, some specific sets of spots were conserved among geographically or epidemiologically related strains. Base sequence variation of the isolates was deduced according to Aaronson et al. (Nucleic Acids Res. 10, 237-246, 1982) from pariwise comparison of the common spots and used as a genetic distance between them. The base substitution rate of virus genome was estimated by regression analysis of the genetic distance of the isolates against the sampling time. A fairly constant and rapid rate was obtained; it was 1.83 X 10(-3)/base/year. Based on the substitution rate, genetic distance and sampling time of the strains, the phylogenetic tree of EV 70 was constructed using Unweighted Pair Group Method Using Arithmetic Averages (UPGMA) (Nei, Molecular Population Genetics and Evolution, North Holland, Amsterdam, 1975). The tree supports the previous hypothesis that evolution of EV 70 started from a single common ancestor. The time of its emergence was estimated to be 1967 +/- 15 months. The virus branched into many strains early during the first pandemic and has evolved in a divergent fashion, yielding genetically polymorphic viruses in the world.

Biological Evolution↗
PubMed1986

Brain swelling and brain oedema in acute head injury.

Chronological changes in diffuse brain swelling and brain oedema were studied in repeated CT studies following a closed head injury. These findings were compared with changes in intracranial pressure (ICP). The grades of diffuse brain swelling were classified into mild, moderate and marked according to the CT findings. Planimetry of low density areas of brain oedema was carried out on repeated CT images. Diffuse brain swelling was recognized in 71% of patients shortly after the head injury and subsided within days 3-5. Brain oedema first appeared 24 hours post injury and did not reach its maximum size and distribution before days 5-8. Thus, these two events can be clearly separated. The intracranial pressure reflected the course of the brain swelling and was not very high during the presence of maximum oedema.

Acute Disease↗
PubMed1986

Enhanced cisternal drainage and cerebral vasospasm in early aneurysm surgery.

Enhanced cisternal drainage was performed following early aneurysm surgery in patients with Hunt and Kosnik grades I-III, to effect continuous wash-out of subarachnoid blood clots and reduce symptomatic vasospasm. Following extensive evacuation of the cisternal blood clots, the Liliequist's membrane was opened extensively and a third ventriculostomy was effected by opening the lamina terminals. The drainage effect was considered as poor, moderate or fair, depending on the average amount of CSF drainage/day. SAH was graded into 0-III depending on the severity of cisternal haematoma in the pre-operative CT. No symptomatic vasospasm occurred in patients with SAH grade I. In SAH grade II + III patients symptomatic vasospasm occurred in 78, 60 and 42% of patients with a poor, moderate and fair drainage effect, respectively. Nine patients who developed symptomatic vasospasm were treated by hypertensive/hypervolemic therapy (HHT). The HHT was effective in 7 patients with fair and moderate CSF drainage and ineffective in 2 patients with poor a drainage effect. It seems, that enhanced post-operative cisternal drainage can reduce the incidence of symptomatic vasospasm and be of benefit to the outcome of early aneurysm surgery.

Blood Pressure↗
PubMed1986

Epivascular glia and paravascular holes in normal human retina.

We examined the retinal surface of 28 autopsy eyes by scanning electron microscopy (SEM). Glialike cells or their processes, arranged in rows, were observed along retinal vessels in 22 eyes. Additionally, there were clusters of glialike cells over retinal vessels in 8 eyes. These proliferations ranged from focal to extensive ones, the latter resulting in distinct preretinal membranes. Focal defects of the superficial retina along the vessel were noted in 6 of 28 eyes. Transmission electron microscopic study in 2 surgically enucleated eyes with normal retinae revealed epivascular retinal degeneration and thinning of Müller cells. Glial processes appeared to be covering the defect of the internal limiting membrane and some projections of these cells continued inwards. These findings were consistent with the SEM findings of epivascular glialike structure. Our conclusions are that epivascular glialike structures and paravascular surface defects appear as a common finding in normal senile eyes, and that occasionally membranous formations arise from the epivascular area.

Adult↗
PubMed1986

Stimulation of fibroblast proliferation and prostaglandin production by purified recombinant murine interleukin 1.

Recombinant murine interleukin 1 (IL-1) obtained from a clone of Escherichia coli containing an IL-1 expression plasmid was purified to homogeneity using a sequential extraction procedure and gel filtration chromatography. The purified recombinant IL-1 exhibited a pI of approximately 5.2 and a sp act of 6 X 10(6) units/mg. These values are in agreement with those obtained with natural murine IL-1. The purified recombinant IL-1 enhanced the proliferation of human HEL and WI-38 fibroblasts in a serum-free medium. In addition, IL-1 stimulated fibroblast PGE2 5- to 30-fold over a 24-hr period. The effects of IL-1 on fibroblast activation were obtained with the same concentrations of IL-1 that are effective in the mouse thymocyte assay. These results unequivocally establish the ability of IL-1 to modulate fibroblast proliferation and function.

Animals↗
PubMed1986

CT findings of leptomeningeal and periventricular dissemination of tumors. Report of four cases.

Four cases of leptomeningeal dissemination of tumors were reported especially focused on their CT findings. These findings consisted of hydrocephalus and contrast enhancement of the quadrigeminal cistern, basal cisterns, Sylvian fissures, cerebro-cerebellar cortical sulci and ventricular wall. Although autopsy of 3 cases revealed diffuse subarachnoid tumor growth in the brain and spinal cord, not all lesions were demonstrated by CT. Therefore, CT findings varied greatly depending on case and course of the disease. Definite diagnosis of this disease could be done by CSF cytology.

Adenocarcinoma↗
PubMed1986

Effects of staged versus sudden reperfusion after acute coronary occlusion in the dog.

Sudden and staged reperfusion after experimental coronary artery occlusion was studied in relation to recovery of cardiac function and postreperfusion arrhythmias. Eighteen closed chest dogs with 3 hour intracoronary balloon occlusion of the proximal left anterior descending coronary artery were studied using two-dimensional echocardiography over a period of 3 weeks after reperfusion. Nine dogs had sudden reperfusion by abrupt balloon deflation. In nine other dogs reperfusion was staged with partial reflow (20 ml/min) for 2 hours through the central lumen of the catheter during persisting intracoronary balloon inflation, followed by balloon deflation and full reperfusion. Within the first 30 minutes of sudden reperfusion, ischemic zone end-diastolic wall thickness increased significantly, from 6.8 +/- 0.3 mm at 3 hours of occlusion to 10.2 +/- 2.6 mm (p less than 0.05). In contrast, at 30 minutes of partial reflow, wall thickness was 7.5 +/- 0.7 versus 6.8 +/- 0.7 mm at 3 hours of occlusion (NS). A small temporary increase in end-diastolic wall thickness was noted when full reflow was established after 2 hours of staged reperfusion. However, wall thickness was normal on the first day in the staged reperfusion series, while sudden reperfusion delayed recovery to 7 days. Function of the ischemic zone failed to improve substantially until day 3 after sudden reperfusion, whereas it improved consistently starting as early as 30 minutes after institution of the staged reperfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1986

Structure-function analysis of murine interleukin 1: biologically active polypeptides are at least 127 amino acids long and are derived from the carboxyl terminus of a 270-amino acid precursor.

Murine interleukin 1 (IL-1) is initially synthesized as a 270-amino acid precursor protein. Guided by amino-terminal end sequence analyses of mouse macrophage-derived IL-1, it was shown that expression of the carboxyl-terminal 156 amino acids (i.e., amino acids 115-270) of this precursor in Escherichia coli yields biologically active recombinant IL-1 (rIL-1) protein. To answer questions about precursor processing and the size of the smallest biologically active IL-1 fragment, we have engineered deletions of the rIL-1 (115-270) gene to encode two amino-terminal deletion analogs, rIL-1 (131-270) and rIL-1 (144-270), and a carboxyl-terminal deletion analog, rIL-1 (131-257, 270). The analogs were produced in E. coli, purified to homogeneity, and assayed for biological activity on murine thymocytes, human rheumatoid synovial cells, and human dermal fibroblasts and for their ability to bind to IL-1 receptors on murine EL-4 thymoma cells. The amino-terminal deletion analog rIL-1 (131-270) possessed a specific activity in the murine thymocyte proliferation assay equivalent to that of the 115-270 parent protein and exhibited significant biological activity in stimulating the production of collagenase and prostaglandin E2 by synovial cells and fibroblasts. The more extensive amino-terminal deletion analog rIL-1 (144-270) was inactive in all biological assays and failed to compete in the receptor binding assay. The carboxyl-terminal deletion analog rIL-1 (131-257, 270) competed less efficiently (by a factor of 100) in the receptor binding assay, retained weak biological activity on synovial cells and fibroblasts, and only demonstrated full intrinsic activity in the thymocyte proliferation assay when 100-200 times more protein was assayed. These results suggest that biologically active murine IL-1 polypeptides are at least 127 amino acids long and are derived from the carboxyl terminus of the 270-amino acid precursor. Furthermore, it appears that the integrity of the carboxyl terminus of the 270-amino acid precursor is important for activity but that different amino termini can be utilized to generate molecules with equivalent specific activities. This amino-terminal end flexibility supports a processing model for IL-1 maturation that partially explains IL-1 polypeptide heterogeneity.

Amino Acids↗
PubMed1986

Determination of the complete amino acid sequence of recombinant human gamma-interferon produced in Escherichia coli.

The complete amino acid sequence of recombinant human gamma-interferon (HuIFN-gamma) produced in Escherichia coli was determined using a gas-phase protein sequencer. The sequence was established by automated Edman degradation on the intact protein and its peptides obtained after Staphylococcus aureus V8 protease or trypsin digestion. The result was identical to the amino acid sequence predicted from the nucleotide sequence of the cloned HuIFN-gamma cDNA except that it was missing the four carboxy-terminal residues, Arg-Ala-Ser-Gln.

Amino Acid Sequence↗