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Biomedical subjects

M Maeda

Publications and source records attributed to M Maeda.

At least 1,315 records · Page 73Linked to original sources
PubMed1984

[Clinical studies on surgical treatment of renal hyperparathyroidism].

While patients of chronic renal failure can survive today for a long period thanks to the spread of hemodialysis, establishment of criteria for the treatment of renal hyperparathyroidism is an important problem. In the 15 cases of renal hyperparathyroidism previously operated by the author, preoperative examinations and findings at the time of operation, and technique of operation and postoperative examinations were analyzed together with the effects of operation, and the indications and technique of operation were discussed. Surgical indication Since the histological findings of resected parathyroids presented chief cell hyperplasia in the whole gland and coexistence of fat tissues was hardly recognized, it was estimated that the weight of parathyroid glands directly reflected the secretory function of the parathyroid glands. Accordingly, the relation between the preoperative findings and weight of parathyroid glands was analyzed. As a result, a significant correlation was noted between the preoperative c-PTH and the weight of parathyroid glands. Hence it was proved possible to predict the approximate weight of parathyroid glands from the preoperative level of c-PTH. Further investigations were made on s-Al-P, s-CT, RMC, roentgenographic findings, ca-infusion test, iliac bone biopsy, subjective symptoms, and weight of parathyroid glands, and the following conclusions were obtained with respect to the surgical indication. 1) When the weight of parathyroid glands was estimated to be above 2000 mg, the operation would be an absolute indication. 2) If the weight is estimated between 1000 and 2000 mg, the operation should be preferred because the improvement by conservative treatment may not be expected. 3) In the case of slight swelling of less than 1000 mg, the first choice of treatment should be conservative. However the operation in the early stage would be essential in the case of calcification of the blood vessel wall. Surgical technique In 10 of the 15 cases operated, subtotal parathyroidectomy was performed. For longer period than 6 months after surgery clinical study was performed with respect to the changes in c-PTH, s-Al-P, CT, RMC, bone roentgenographic findings, s-Ca, s-P, iliac bone biopsy, and subjective symptoms. As a result, the postoperative course was good in patients in whom the subtotal parathyroidectomy was performed with 20 to 50 mg of the remaining parathyroid tissue. The value of c-PTH was stabilized in 3 months after the operation, and was thereafter controlled within normal ranges. In view of the possibility of the recurrence, the desirable weight of the remaining parathyroid tissue would be 20 to 30 mg.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1984

[Parenteral replacement of thyroid hormones].

Because of the development in parenteral nutrition, the replacement of thyroid hormones in hypothyroid or athyroid patients under intravenous hyperalimentation has become a new problem to be considered. We tried parenteral replacement of the hormones, intravenously or by enema, in three such patients. Two patients, 54 y-o and 64 y-o females, who underwent laryngo-esophago-thyroidectomy for cervical esophageal cancer or thyroid cancer, had replacement with intravenous l-thyroxine with an initial dose of 100 micrograms/day for 9 and 22 days, respectively. Another patient, a 56 y-o female with dysphagia due to local recurrence of cervical esophageal cancer after laryngo-esophago-thyroidectomy, was given 100 mg of desiccated thyroid by enema for 8 days followed by intravenous l-thyroxine for 104 days. Serum levels of thyroxine, triiodothyronine and TSH before l-thyroxine treatment indicated severe hypothyroidism in all cases. During the first 7 days of the intravenous therapy, serum thyroxine and triiodothyronine levels increased by 0.87 +/- 0.14 microgram/dl/day and 6.7 +/- 4.7 ng/dl/day, respectively, while serum TSH levels decreased by 7.8 +/- 6.4 microU/ml/day. Plasma T4 levels reached the normal level within 7 days, and plasma T3 levels within 11 days, while it took 14 days for plasma TSH levels to decrease to the normal level. The maintenance dose checked by the normal TSH levels in a patient undergoing a long term therapy was 75 micrograms/day or 1.83 micrograms/kg of body weight/day.(ABSTRACT TRUNCATED AT 250 WORDS)

Enema↗
PubMed1984

Radical operation for thyroid carcinoma invading the trachea.

We report 12 cases of well-differentiated thyroid carcinoma that invaded the trachea. In all of these cases, we performed a hemithyroidectomy, including the isthmus, with an accompanying neck dissection and resection of the trachea. Six of 12 patients experienced hemoptysis, and a diagnosis of tracheal invasion was made preoperatively in nine patients by tracheal endoscopy and computed tomography. Histologic diagnosis was confirmed by a preoperative biopsy in one case only. An end-to-end anastomosis of the trachea was performed in five patients, an anastomosis between the cricoid cartilage and the trachea was performed in five patients, and an anastomosis between the thyroid cartilage and the trachea was performed in two patients. One patient with a recurrence of tumor died of tracheal bleeding 11/2 years later. One patient died of massive gastrointestinal bleeding postoperatively. The remaining ten patients have been doing well from three months to five years two months postoperatively.

Adenocarcinoma↗
PubMed1984

Exocrine and endocrine secretion from isolated perfused rat pancreas with islet cell tumors induced by streptozotocin and nicotinamide.

Pancreatic exocrine and endocrine function in the rat with islet cell tumors induced by streptozotocin and nicotinamide was studied in the in vitro isolated perfused pancreas. The tumor-bearing pancreas secreted significant amounts of insulin even at 2.8 mM glucose stimulation. Further, insulin response to 8.3 mM glucose stimulation was greater in the tumor-bearing pancreas than in the control. Not only endocrine, but also exocrine, disorders were found in the rat pancreas bearing islet cell tumors. In contrast to the increased response of insulin, amylase output in response to 0.1 ng/ml cerulein was significantly lower in the tumor-bearing than in the control pancreas, although there was no difference in pancreatic juice flows from both groups. These results suggest that enzyme secretory function of the pancreas with islet cell tumors may be suppressed in the presence of some interrelationship between the exocrine and endocrine portion of the pancreas with islet cell tumors.

Adenoma, Islet Cell↗
PubMed1984

Attenuation values of chronic subdural haematoma and subdural effusion in CT scans.

When peripheral blood is serially diluted with saline solution, the bloody colour is determined by the derivative of haemoglobin. Solutions over 10(5)/mm3 red cells or 0.5 g/dl haemoglobin are represented as being sanguineous. This is the lower limit for a subdural haematoma, because the name itself requires at least a bloody appearance of its contents. Diluted blood solutions less 0.5 X 10(4) red cells or 15 mg/dl haemoglobin are macroscopically translucent or watery clear. Solutions between bloody and translucent are xanthochromic. If the contents of a subdural collection is watery clear or xanthochromic, it must be called an effusion or hygroma. The haemoglobin in haematomas is the most important factor determining the attenuation values in the CT scan. Protein, iron or calcium ions have only minimal concentration in haematomas and are negligible for attenuation values of haematomas in the CT scan. The lightest sanguineous solution, that is a haematoma, corresponds to 15 Hounsfield's units measured by the CT scan.

Chronic Disease↗
PubMed1984

Carrier-added and no-carrier-added syntheses of [18F]spiroperidol and [18F]haloperidol.

Syntheses of [18F]haloperidol and [18F]spiroperidol in both no-carrier-added and carrier-added forms have been accomplished. The no-carrier-added [18F]butyrophenone neuroleptics were prepared in low (less than 2%) yield by acid decomposition of aryl piperidine triazenes. Carrier-added 18F-neuroleptics were prepared in better (5-17%) yields by 18F-for-19F nucleophilic aromatic substitution. The preparation of all synthetic precursors, and procedures for radiolabeling are fully described.

Butyrophenones↗
PubMed1984

Synthesis and antitumor activity of cis-dichloroplatinum (II)-N-aminated nucleoside complexes.

N-Aminated nucleoside complexes of cis-dichloroplatinum(II) were synthesized, and their antitumor activities against L1210 cells in mice and in vitro were studied. While the native nucleosides failed to show any antitumor activity, the complexes exhibited high antitumor activity and had no nephrotoxicity in mice. Studies on their mode of action in vitro indicated that the ligands played characteristic roles in the appearance of antitumor activity; ribonucleoside complexes caused the inhibition of RNA synthesis, and deoxyribo- or arabinonucleoside complexes caused the inhibition of DNA synthesis.

Animals↗
PubMed1984

The cocarcinogenic effect of intrarectal deoxycholate in rats is reduced by oral metronidazole.

Bile acids enhance colorectal carcinogenesis in animals and man, perhaps after degradation by faecal anaerobes. The promotional effect of sodium deoxycholate (SDC) and its relationship to bacteria was examined in male Sprague-Dawley rats (n = 115) which had received a 6-week course of azoxymethane (total dose 90 mg kg-1 s.c.) Two groups received 3 X weekly intrarectal (i.r.) instillations of N saline or 0.12 M SDC for 18 weeks. Another group received SDC i.r. plus metronidazole (22.5 mg kg-1) daily in the drinking water. Controls had no instillations or metronidazole alone. By 28 weeks SDC had increased mean colonic crypt depth by 9% (P less than 0.001), and had almost trebled colorectal tumour yields from 2.4 +/- 0.4 per rat (mean +/- s.e.) in controls to 6.4 +/- 0.5 (P less than 0.001). Tumour yields after SDC + metronidazole (4.2 +/- 0.5) remained 75% higher than in controls (P less than 0.01) but were 33% less than after SDC alone (P less than 0.01), and the increase in crypt depth was maintained at 7% (P less than 0.001). Neither metronidazole alone nor saline i.r. had any effect on tumour yield, but metronidazole alone reduced crypt depth by 9% (P less than 0.001). Deoxycholate is a potent cocarcinogen and also stimulates mucosal hyperplasia. Metronidazole reduces its tumour-promoting effect, suggesting that faecal anaerobes are important in bile acid cocarcinogenesis.

Animals↗
PubMed1984

Effect of short-term peroral administration of synthetic trypsin inhibitor on endocrine secretion in the isolated perfused rat pancreas.

The effects of peroral treatment with synthetic trypsin inhibitor on endocrine secretion in response to four different stimuli were investigated in the isolated perfused rat pancreas. After 10 days' treatment pancreatic wet weights and protein and amylase contents in the pancreas were significantly increased. On the other hand, total contents of IRI and IRG in the T.I.-treated and control pancreas were nearly the same. In spite of the lack of alteration in hormone contents, a lower initial phase of IRI response to 8.3 mM glucose, glucose plus 0.1 ng/ml caerulein or 20 mM arginine was observed in the T.I.-treated pancreas. Furthermore, the IRI response to 10 mM theophylline was both slower and the most reduced in the T.I.-treated pancreas. From these observations, it is suggested that short-term peroral administration of synthetic trypsin inhibitor not only has no trophic effect on pancreatic B-cell and A-cell in the rat but also may affect some pathway of insulin secretion from the B-cell to reduce IRI responses to secretagogues.

Amylases↗
PubMed1984

Relation of doubling time of plasma calcitonin levels to prognosis and recurrence of medullary thyroid carcinoma.

Plasma calcitonin (CT) levels were measured serially in 54 patients surgically treated for medullary thyroid carcinoma. Patients with postoperative basal CT levels higher than 1 ng/ml measured within 1 month after surgery had a higher recurrence rate than those with lower CT levels (p less than 0.002). Patients with postoperative basal CT levels higher than 2 ng/ml had a lower survival rate than those with lower CT levels (p less than 0.01). However, preoperative basal CT levels had no significant correlation with life expectancy or recurrence during the present observation period. Serial measurements in 23 patients with elevated postoperative CT levels showed exponential increases in basal CT levels in 19 patients (p less than 0.05 in nine patients, 0.05 less than p less than 0.1 in four patients) and slight decreases in four (p less than 0.05 in one patient). Doubling time of CT levels calculated from the regression line in each patient showed the highest correlation with 3-year survival, recurrence within 5 years, and time interval between surgery and clinical recurrence of the tumor, allowing quantitative prediction of the prognosis.

Calcitonin↗
PubMed1984

Malignant fibrous histiocytoma developing in a burn scar.

A case of malignant fibrous histiocytoma (MFH) developing in a burn scar is presented. The patient was burnt at 3 years of age and 25 years later, a rapidly growing tumour developed in the burn scar. MFH was diagnosed by light and electron microscopy and by an immunoperoxidase method. This complication of a burn scar has not been previously reported.

Adult↗
PubMed1984

Emergence of permanent teeth and onset of dental stages in Japanese children.

The purpose of the present cross-sectional study was to provide mean times of emergence of permanent teeth and onset of dental stages in Japanese children. A total of 1819 schoolchildren aged 6-15 yr were recorded. The results demonstrated specific sequences of emergence in the two arches and earlier emergence times in girls than in boys, both findings in keeping with investigations on other ethnic groups. Secular trend in tooth emergence was studied by comparing the results with data on Japanese children in 1934. The comparison revealed earlier mean times of emergence in general in contemporary Japanese.

Adolescent↗
PubMed1984

Accommodation to a reduced islet cell mass in dogs.

The quantitative insulin response to glucose stimulus can be drastically reduced by subtotal pancreatectomy. An 80% pancreatectomy was performed preserving the pancreatic duct in seven dogs. The insulin output into the portal vein and cephalic vein insulin after intravenous glucose challenge were measured. Output was recorded in 25 controls, and before and 2 wk after subtotal pancreatectomy in the seven animals. Histologic sections of the original resection were compared with the remnant of pancreas taken at the end of the study. In this model, which approaches islet cell failure in terms of glucose homeostasis, the tactics that permit enhancement of islet function can be discerned and to some degree quantitated. The pancreatic remnant does not oversecrete to approximate normal function, although glucose sensitivity is somewhat enhanced. No beta-cell hyperplasia was seen. Despite low insulin output into the portal vein, systemic insulin levels are conserved. This decrease in the plasma clearance of insulin supports glucose homeostasis. Accommodation to severe islet reduction occurs via both intrapancreatic and, more importantly, extrapancreatic mechanisms.

Animals↗
PubMed1984

Evidence that the 5'-monodeiodinases for thyroxine and 3,3',5'-triiodothyronine in the rat pituitary are separate enzymes.

Studies were directed at the question of whether the enzyme that mediates the 5'- or outer ring monodeiodination of T4 is the same as that which mediates the 5'-monodeiodination of rT3. Advantage was taken of previous observations which indicated that T3, when administered to the hypothyroid rat, acutely inhibits the 5'-monodeiodination of T4 to yield T3 in hemipituitaries in vitro. In the present experiments, these effects of T3 on the generation of T3 from T4 were confirmed in both hemipituitaries and homogenates, indicating that they were not due to an effect of T3 on the cellular penetration of the [125I]T4 used as substrate. In contrast, in separate experiments with both hemipituitaries and homogenates, T3 had no effect on the metabolism of [125I]rT3, including its 5'-monodeiodination to yield 3,3'-diiodothyronine. In other experiments, the divergent effects of T3 on the metabolism of T4 and rT3 were also observed when the two substrates were studied in paired hemipituitaries and paired aliquots of the same pituitary homogenate. Failure of T3 to inhibit the 5'-monodeiodination of rT3 in pituitary homogenates could not be explained by the presence of marked enzyme excess, since T3 was also without effect when homogenates were incubated with rT3 at a concentration of 1 microgram/ml. In additional experiments, propylthiouracil (PTU) in vitro (1 mM) was found to have no effects on either the rapid metabolism of [125I]T4 seen in the pituitaries of hypothyroid rats or the less rapid metabolism of [125I]T4 seen in pituitaries of hypothyroid rats given T3. In contrast, though PTU failed to alter the metabolism of [125I]rT3 in pituitaries of hypothyroid rats, it greatly inhibited the metabolism of [125I]rT3 in the pituitaries of hypothyroid rats given T3. These results are consistent with those in previous reports which indicate that the pituitary contains two enzymes that mediate the deiodination of T4 and rT3. One is a PTU-insensitive enzyme that mediates the 5'-monodeiodination of T4; its activity is increased in hypothyroidism and is decreased by T3 replacement. The other is a PTU-sensitive enzyme that mediates much of the 5'-monodeiodination of rT3 in the pituitary of the T3-replaced rat, as in the euthyroid rat, but whose activity is largely supplanted by that of the PTU-insensitive enzyme in hypothyroidism.

Animals↗
PubMed1984

Control of cellular differentiation by temperature in the cellular slime mould Dictyostelium discoideum.

The effects of low temperature on morphogenesis and cellular differentiation of Dictyostelium discoideum were examined. During incubation at 5 degrees C, the vegetative and preaggregation cells never developed, but cell masses at the aggregation or slug stage developed to form hemispherical, or dumbbell-shaped multicellular structures. By staining with FITC-antispore IgG, the structures formed after 10 days of incubation of tipped aggregates at 5 degrees C were found to be composed of 90% spores, 5% prespore cells and 5% non-stained cells. Since only 20% of the total cells constituting the tipped aggregate had been prespore cells at the beginning of incubation, this showed that spore differentiation proceeded even at low temperature, while stalk differentiation was completely inhibited. Similar results were obtained when the cells were incubated at 3 degrees C. However, at 0 degree C, morphogenesis and cellular differentiation did not occur, although most of the prespore cells at the late culmination stage differentiated incompletely into spores. Possible reasons for the high proportion of spores being induced by low temperature are discussed.

Cold Temperature↗