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Biomedical subjects

M Ohata

Publications and source records attributed to M Ohata.

At least 145 records · Page 8Linked to original sources
PubMed1977

Control of parathyroid hormone hydrolysis by the kidney.

In order to assess the role of the kidney in controlling the degradation, fate, half-life, and consequently the functional level of the parathyroid hormone in vivo, highly purified bovine parathyroid hormone (bPTH 1-84) and synthetic N-terminal peptide of the bovine parathyroid hormone (bPTH 1-34) were iodinated and their hydrolysis by the kidney and liver tissue of rats were measured under various levels of parathyroid function and calcium metabolism. While the hydrolysis of bPTH 1-84 did not change significantly in response to acute change of serum parathyroid hormone in response to injections of EDTA, phosphate, and calcium or after parathyroidectomy, less bPTH 1-34 was hydrolyzed 60 min after injection of EDTA or phosphate along with the rise of serum PTH than in the controls. No significant change was found in the hydrolysis of bPTH 1-34 after calcium infusion or parathyroidectomy with a consequent fall of serum parathyroid hormone. Increase of calcium ions in the incubation medium in vitro resulted in a more pronounced increase of bPTH 1-34 hydrolysis than that of bPTH 1-84. Hydrolysis of the N-terminal portion of parathyroid hormone probably plays a more important role in the acute control of the functional level of the parathyroid hormone than the hydrolysis of the whole molecule.

Animals↗
PubMed1977

Endocrine control of the intestinal calcium excretion.

Calcium excretion from rat intestine was measured by placing distilled water in an intestinal loop in situ and measuring the calcium content after various intervals. More calcium was excreted from the intestine of 18-month-old rats than that of 1-month-old rat. Acute hypocalcemia failed to change the intestinal calcium excretion significantly. Parathyroidectomy decreased intestinal calcium excretion and administration of Parathyroid Extract reversed it. Renal damage produced by injection of Na-sulfacetylthiazole increased the intestinal calcium excreation but dihydrotachysterol reversed it. Gastrin at 200 microng/kg increased the intestinal calcium excretion. Calcium excretion, like calcium absorption, appears to be controled by various endocrine factors and the method of intestinal loop in situ appears to be useful to study the part played by these factors.

Animals↗
PubMed1977

Effect of 1alphaOH-vitamin D3 in a case of pseudohypoparathyroidism.

A 37-year-old woman with typical features of pseudohypoparathyroidism (chronic tetany, paresthesia, persistent hypocalcemia, round face, short stature, short metacarpals and metatarsals, cucutaneous calcification and lack of response to exogenous and endogenous parathyroid hormone as regards urinary phosphate and cyclic AMP excretion) was treated with oral administration of 2 microgram/day of 1alphaOH-vitamin D3. Serum calcium started to rise within 3 days returning to the normal level with disappearance of symptoms referrable to hypocalcemia. Such a favorable effect of a small dose of 1alphaOH-vitamin D3 in a patient with typical hypoparathyroidism suggests an important role of disturbance of 1alpha-hydroxylation of vitamin D3 by the kidney in the pathogenesis of calcium and phosphorus abnormality in this disease. Forty-four cases of pseudohypoparathyroidism in the Japanese literature were briefly reviewed.

Administration, Oral↗
PubMed1977

Elevation of serum 25-hydroxycalciferol levels in androgen-treated and ultraviolet-irradiated rats.

Administration of 4-8 mg testosterone propionate significantly raised 25-hydroxycalciferol levels in the ultraviolet irradiated rats compared to the ultraviolet irradiated controls, but failed to influence serum 25-hydroxycalciferol levels in the non-irradiated animals. Estradiol benzoate and progesterone did not influence serum 25-hydroxycalciferol levels regardless of the ultraviolet irradiation. These findings implicate that testosterone enhances vitamin D biosynthesis induced by ultraviolet irradiation in rats, in accordance with the clinical observation that males often show higher levels of serum 25-hydroxycalciferol than females.

Animals↗
PubMed1976

Aging and parathyroid hormone secretion.

Influence of age on parathyroid hormone secretion and release was studied in vitro using rat parathyroid glands in culture and in vivo by EDTA injection. Parathyroid hormone was measured by radioimmunoassay using guinea pig antibody for bovine parathyroid hormone and 125I-labeled synthetic N-terminal peptide of bovine parathyroid hormone. Significantly less PTH was released from parathyroid glands of 18-mo-old rats than from those of 1 mo of age at various calcium concentrations of the medium in vitro. Secretion of parathyroid hormone in response to EDTA-induced hypocalcemia in vivo was also less in older rats than in younger ones, giving lower deltaPTH/deltaCa values in the older animal. Secretion of parathyroid hormone therefore appears to decrease along with aging in rats.

Aging↗
PubMed1976

Possible function of human brown adipose tissue as suggested by observation on perirenal brown fats from necropsy cases of variable age groups.

In 134 out of 180 perirenal fat samples (74%) derived from Japanese necropsy cases aged from 1 month to 86 years, the brown fat tissue persisted in variable amounts. Brown fat cells were classified into 6 types: Type 1 cells are fat-depleted cells filled with granular cytoplasm and are believed to be produced after oxidation of fat for heat production. Type 2 cells are small-locular cells suitable for rapid oxidation of fat droplets. Type 3 (middle-locular) and 4 (large-locular) represent fat-storage cells containing large amounts of fat. Type 5 cells are thought to be transitional forms between multilocular brown fat cells and monolocular white fat cells. Type 6 (cytoplasm-rich multilocular) cells, usually found together with Type 1 cells, are thought to be fat-depleting or -consuming cells, since in them fat droplets are reduced in number and size probably in consequence of oxidation of fat, but by contrast granular cytoplasm is increased in amount separating the individual fat droplets by thick cytoplasmic septa. The occurrence of Types 1 and/or 6 cells that has been revealed in 65 out of the total 180 samples (36%), suggests that the oxidation of fat for the thermogenesis proceeds in the brown fat tissue and that brown fat cells partially undergo fat depletion. In the present study, the thermogenesis of human brown fat tissue was suggested chiefly with regard to the occurrence of Types 1 and/or 6 cells. In the majority of perirenal fat samples from infants (1-11 months) relatively numerous Types 1 and 6 cells were frequently revealed together with Type 2 cells, suggesting rapid and active heat production in support of the view that in human infants the brown fat tissue may be thermogenetically active to maintain body temperature. In the same manner, marked ability to produce a considerable amount of heat was evidenced in brown fat tissue of children and teenagers. In younger and elderly adults the frequency of occurrence and the amount of the perirenal brown fat tissue were decreased but Types 1 and/or 6 cells could be found in 17-40% of them, infrequently together, with Type 2 cells, suggesting persistence of the thermogenic activity with occasional large heat production especially in younger adults (20-39 years). Thus, the results obtained in this study have clarified that the human brown fat tissue can respond to stimuli given to the body by oxidation of stored fat even in the latest decades of life. In cases of death from burning, drowning, bleeding, drug poisoning etc., numerous Types 1 and/or 6 cells were found, suggesting that an active fat oxidation would take place in brown fat tissue assumedly as the result of the raised noradrenalin level in this tissue. The so-called small cytoplasmic cells found in perirenal fats from cases of death from liver cirrhosis and other causes were assumed to be atrophic fat-depleted brown fat cells.

Adipose Tissue, Brown↗
PubMed1976

[Meningioma in the aged--on its differential diagnosis (author's transl)].

Despite vast improvement in diagnostic techniques in neurosurgery during the past few decades, there still remain a significant number of intracranial tumors in geriatric age group, which are not recognized in the early course of the disease or during life. We are now focusing on the diagnostic problems of meningiomas in the geriatric age group and stressing the significant value of brain scanning in the differential diagnosis of brain tumors from cerebral vascular disease or other conditions. During about 10-year period, a total of 36 intracranial tumours in cases over 60 year old have been studied. Sixteen of these tumors are meningiomas and form the basis of this report. The age of these cases was between 60 and 83 years with average of 70.5. There were two males and 14 females. As to the location, four were parsagittal and falx meningiomas, three were at tuberculum sellae, two were at sphenoidal ridge, one was at tentorium in location. Twelve cases were erroniously diagnosed and confusion with cerebrovascular disease was most common. We analysed the onset and the progression of symptoms of our 16 cases, and picked up and stressed the four peculiarities of geriatric meningiomas. The first one is that the onset of symptoms is very sudden, almost precipitate, and the subsequent clinical course may be so rapidly progressive. The six patients in our cases were included in this group. A case among those was verified to be complicated with intratumoral hemorrhage, and another one with a subdural hematoma. The vast contrast to the first group is the second peculiarity. The meningioma especially in the geriatric age group may frequently unfold a clinical picture, which by its very insidious onset and slow development may be even unrecognized during life. The third is that patients developed dementia, at the onset in two cases and in any course of this disease in six. All too frequently in these instances the tumor has been overlooked and wrongly diagnosed as a senile dementia or psychosis. The fourth is that the meningioma developed with intermittent, recurrent and streotyped cerebral symptoms including epilepsy. We presented a case with intermittent aphasia due to a convexity meningioma on the dominant side. In almost all cases, manifestation of increased intracranial pressure was absent or not significant. There was found a papilledema in only one case, and cerebrospinal fluid revealed a normal pressure in six out of eight cases in which lumbar puncture was performed. It was proved that brain scanning was one of the most useful adjuncts in the diagnosis of brain tumor in the aged even in serious conditions. Changing brain scan patterns in association with clinical course is a useful diagnostic guide in differentiating tumors from cerebrovascular accidents. The serial scan density change is more meaningful if the clinical course is considered. Scanning should be done as soon as possible when the brain tumor is suspected and should be rescanned if necessary.

Age Factors↗
PubMed1976

[The epidermoid tumor of the lateral cerebral ventricle; report of a case (author's transl)].

The authors report a case of epidermoid tumor of the lateral ventricle. Epidermoid tumors are relatively uncommon intracranial lesions and the one situated in the lateral ventricle has not been reported in this country. A 42 year old house wife was admitted to Asahi Central Hospital on February 14, 1973, complaining of progressive right hemiparesis for 2 years. The patient had no headache and no other symptoms of increased intracranial pressure. Neurological examination revealed disorientation, dyscalculia, amnestic aphasia, morter dysphasia, right facial paresis (central type) and right hemiparesis. The laboratory findings, which included complete blood count, serum electrolytes, urinalysis, electrocardiogram and blood Wassermann, were normal. Initial pressure of the spinal tap was 410 mmH2O and crystal clear CSF was obtained. tplain craniogram showed no calcification and was normal. The left CAG showed clearly the signs of the temporal lobe tumor (Fig. 1, 2, 3, 4.), but showed no early veins and no tumor stains. The brain scintigram was normal. A left temporo-parietooccipital craniotomy was performed. The epidural Echogram (horizontal section-Fig. 5, coronall section-Fig. 6) revealed the clear demarcated, multicystic round tumor in the inferior horn of the left lateral ventricle. After the whitesoap like tumor was totaly removed, the all interior surface of the left inferior horn of the lateral ventricle was seen (Fig. 8). Tumor was 5.5 cm in diameter and 50 g in weight. Histological findings of the tumor showed typical epidermoid (Fig. 9, 10). The origin of the intravetricular epidermoids and the usefulness of echo-encephalorgaphy were briefly discussed.

Adult↗
PubMed1976

[Evaluation of shunt therapy in normal pressure hydrocephalus-surgical results in neurological conditions (author's transl)].

This presentation is a study of 18 patients diagnosed as having normal pressure hydrocephalus and treated by CSF diversion procedures. Pre- and postoperative neurological conditions of these patients were evaluated, compared, and analysed. There were 56% of males and 44% of females and the number of patients under 60 and over 61 were equal. The histories and clinical findings in all suggested a diagnosis of normal pressure hydrocephalus. In 12, the two thirds of patients, showed progressive intellectual deterioration, ataxic gait and/or incontinence following subarachnoid hemorrhage. Similar neurological features were preceded by craniocerebral trauma in one, megadolichobasilar artery in one and superior sagittal sinus thrombosis in one. Three cases were idiopathic. 169Yb cisternography, transfer test of radioisotope to blood, angiography and in some cases pneumoencephalography were performed in the usual manner to confirm the diagnosis. Attempts have been made to correlate the surgical results with the ages of patients, the duration of symtoms, and the causes of hydrocephalus. Neurological symptoms were divided into three groups. Group "A" is composed of mental deterioration, lack of spontaneity and willingness, mutism and disorientation, groups "B" includes gait disturbance and group "C" incontinence. The results of surgical treatment were analyzed according to the three groups of symptoms not only in the percentage of cases who improved but also in the time interval from the time of shunting to the appearance of operative results. The results are as follows. The good surgical improvements were achieved in the cases of under 70 years old, in the case of NPH of known causes, such as subarachnoid hemorrhage, craniocerebral trauma, and in the cases operated on within three months after the onset of symptoms. Recovery of "A" symtoms was achieved not only sooner after the operation but also in more cases than those of "B" and "C" symptoms. The correlation was analyzed between the duration or symptoms and time interval after the shunting and the appearance of operative results. Although no correlation was obtained in "A" symptoms, the sooner was shunting performed, the earlier appeared the operative results in "B" and "C" symptoms. In conclusion, it appeared from the results of the present study, that in addition to the integration of the results of different examinations such as isotope cisternography, air study and angiography, the combination of the patient data such as ages, duration of symptoms and the cause of hydrocephalus are essential in selecting the patients for shunting operation. If the diagnosis of normal pressure hydrocephalus is confirmed and surgical improvement is predicted, the patient should be shunted as soon as possible to obtain a good surgical results especially in mental symptoms, which is the important factor in performing rehabilitation therapy.

Adult↗
PubMed1975

Effect of diphosphonate on crystallization of calcium oxalate in vitro.

Reliable techniques for the calculation of activity product (state of saturation), formation product (limit of metastability) and crystal growth of calcium oxalate were devised. The activity product at saturation was 2.53 times 10 minus 9 M2, and was independent of duration of incubation, solid-to-solution ratio, pH, calcium concentration or ionic strength. These tehcniques were utilized to assess the effect of disodium ethane-1-hydroxy-1, 1-diphosphonate (EHDP) on crystallization of calcium oxalate in an aqueous salt solution in vitro. EHDP increased the formation product of calcium oxalate, indicating an inhibition of nucleation of calcium oxalate. Further, it inhibited the crystal growth of calcium oxalate.

Calcium↗