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Biomedical subjects

H Shimabukuro

Publications and source records attributed to H Shimabukuro.

At least 37 records · Page 2Linked to original sources

[Marked effect of furosemide and hypertonic saline in the treatment of SIAD after head injury].

A case of SIADH after head injury was encountered and treated successfully with furosemide and hypertonic saline. 250 mg of furosemide was given twice at two hours' interval. The dose of 2.5% saline for the infusion was calculated according to the excretion of sodium in the urine collected during this period. The level of serum sodium quickly rose from 113 mEq/l to 137 mEq/l in 33 hours. The consciousness of the patient returned to normal. The problems of quick correction of hyponatremia including the central pontine neurolysis were discussed.

Adult↗

Trigeminal neurinoma revealed by intratumoral hemorrhage following a minor head injury.

A trigeminal neurinoma which produced the signs and symptoms of a localized intratumoral hemorrhage without showing any extratumoral hemorrhage successive to a minor head injury is reported here. A 33-year-old man noticed pain and hypesthesia on the right side of the forehead and double vision on the day following an occipital trauma. A computed tomographic scan demonstrated a large high-density mass in the anterior part of the right cerebellopontine angle. A diagnosis of trigeminal neurinoma was made and the tumor was successfully removed. The largest part of the tumor consisted of a blood clot and necrotic tissue. In this case of minor head injury, the intratumoral hemorrhage was thought to have occurred as a result of obliteration of the lumen followed by recanalization of the meningeal vessels enclosed in the tumor by the growing neurinoma and distal vessel necrosis. Such a case of trigeminal neurinoma which revealed itself through intratumoral hemorrhage following a minor head injury has not been previously reported.

Adult↗

The development of intracranial aneurysms associated with pulseless disease.

Two cases of pulseless disease associated with intracranial aneurysms, one located at the tip of the basilar artery and the other at the left internal carotid-posterior communicating artery junction which developed with episodes of subarachnoid hemorrhage due to their rupture, are presented. Whether the aneurysms and pulseless disease occurred independently or whether the aneurysms developed secondarily from the altered hemodynamic flow produced by pulseless disease is unknown; however, it is certain that abnormal intracranial hemodynamic forces play a role in the development of aneurysms.

Adult↗

Ultrastructural localization of carbonic anhydrase activity in the rat choroid plexus epithelial cell.

Localization of carbonic anhydrase activity was studied electron microscopically on cells of the rat choroid plexus epithelium. For the ultracytochemical detection of these activities, Yokota's technique (1969), which is the modification of Hansson's method (1967) was employed. Numerous electron dense reaction products were observed in the microvilli of the choroidal epithelial cell. The reaction deposits were also remarkably present in the infoldings of the basal plasmalemma but to a lesser extent than in the microvilli. The localization sites were mainly on the plasma membrane, but some reaction products were also observed in the cytoplasm near the plasma membrane. Hardly any reaction product was found in the intracellular organelles except for the mitochondria in which reaction products were occasionally observed on the cristae. These activities were completely inhibited by acetazolamide. As the carbonic anhydrase activity was histochemically seen in the microvilli and the basal infoldings, it is likely that carbonic anhydrase is related to an active transport process in the secretion of cerebrospinal fluid as is Na+, K+ -ATPase (Masuzawa et al. 1980).

Animals↗

The enzyme cytochemistry of the intracellular organelles in the rat choroid plexus epithelial cell.

Electron microscopic cytochemical studies on the rat choroid plexus epithelium have revealed enzymatic sites for the activities of acid phosphatase, glucose-6-phosphatase and thiamine pyrophosphatase on different organelles. Only the activity of acid phosphatase has been previously described. Acid phosphatase, glucose-6-phosphatase and thiamine pyrophosphatase were respectively situated mainly in the lysosomes, in the endoplasmic reticulum an nuclear envelope, and in the Golgi complex. These three enzymes can thus be considered as marker enzymes for their respective organelles in the choroid plexus epithelial cells as well as in other tissue cells. The possible function of these enzymes in the choroid plexus epithelial cells is also briefly discussed.

Acid Phosphatase↗

Ultrastructure of disseminated choroid plexus papilloma.

A disseminated choroid plexus papilloma (DCPP) with a malignant change in the cervico-spinal leptomeninges observed 4 years after the removal of choroid plexus papilloma (CPP), originating from the fourth ventricle, was studied under the electron microscope. Although the ultrastructure of intracranial CPP has been reported by several authors, there are just a few reports on DCPP. The present tumor was ultrastructurally very similar to normal choroid plexus, but the lack of the capillary fenestration and of invaginations of the epithelial basal plasmalemmas suggested that the epithelium was deprived of secretory function.

Cerebral Ventricle Neoplasms↗

Mode of action of bacterial collagenase on a synthetic substrate, (Pro-Pro-Gly)5.

Clostridial collagenase (EC 3.4.24.3) catalyzes the hydrolysis of (Pro-Pro-Gly)5 at minimum of three different rates, producing Pro-Pro, Gly-Pro-Pro and Gly-Pro-Pro-Gly, and various intermediate peptides. The intermediate and final products were separated by cation-exchange column chromatogrphy and identified, and their rates of formation were measured. Pro-Pro was released most rapidly with formation of the tridecapeptide. After the initial release of the N-terminal Pro-Pro, hexa- and heptapeptides were formed in larger amounts than tri-, tetra-, nona- and decapeptides from the tridecapeptide. The rates of disappearance of the intermediates decreased in the order trideca- greater than deca- and nona- greater than heptapeptide. The results indicate that the enzyme hydrolyzes inner linkages of the tridecapeptide having N- and C-terminal Gly residues, forming large peptides, preferentially to outer linkages, forming the tri- and tetrapeptides.

Clostridium↗

Peptide inhibitors of angiotensin I-converting enzyme in digests of gelatin by bacterial collagenase.

Peptide inhibitors of angiotensin I-converting enzyme (peptidyldipeptide hydrolase, EC 3.4.15.1) were produced by digesting gelatin with bacterial collagenase. The inhibitors were isolated from the digests with a combination of alcohol fractionation, treatment with Amberlite CG-50 column, gel filtration through Sephadex G-25, and Dowex 50 column and paper chromatography. Nine peptide fractions were purified to apparent homogeneity judging by thin-layer and ion-exchange column chromatography, and amino acid composition. Amino acid sequences of the peptides were determined: 2 were found to be mixtures of peptides and the sequence of another was only partially determined. Six of the peptides were potent inhibitors of the converting enzyme, while the other three were less active. 6 peptides were substrates for the enzyme. The enzyme released a dipeptide, Ala-Hyp from one peptide and was strongly inhibited by this dipeptide. The remainder of the parent peptides was a less effective inhibitor.

Amino Acid Sequence↗