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Biomedical subjects

T Yamagami

Publications and source records attributed to T Yamagami.

At least 181 records · Page 10Linked to original sources
PubMed1986

Transsphenoidal extracapsular approach to pituitary tumors.

Two years' experience with an extracapsular transsphenoidal approach to pituitary adenomas is presented. Some pituitary tumors contain an inordinate amount of connective tissue that often makes transsphenoidal resection difficult. By opening the tumor capsule and adjacent arachnoid membrane, such tumors with suprasellar extension can be safely removed. In some cases of functioning adenoma, resection of the diaphragma sellae and adjacent arachnoid membrane results in hormonal control. Among 62 cases of transsphenoidal surgery for pituitary adenomas, eight cases required this procedure. The surgical procedure is described and the cases are summarized. The indication and limitations of this procedure are discussed.

Adenoma↗
PubMed1986

[CT findings of growth hormone secreting pituitary adenomas].

The value of high-resolution computed tomography (CT) in the diagnosis of pituitary adenoma has recently been stressed, especially of the coronal view with contrast enhancement. Analysis of the CT scans of 33 growth hormone (GH) secreting pituitary adenomas was done (11 cases of microadenomas, 7 cases of intrasellar adenomas and 15 cases of macroadenomas with suprasellar extension). In macroadenomas, the density was high in five cases, high with isodense portion in two cases, mixed in four cases, isodense in three cases, and isodense and low dense in one case. Six adenomas showed homogeneous density and nine were heterogeneous. After contrast enhancement, two cases showed marked enhancement, ten cases mild and three cases ring enhancement. Margin of adenoma was smooth in nine cases and irregular in six. Among seven cases of intrasellar adenoma one accompanied primary empty sella. In microadenomas ten of eleven cases had hypodense mass inside the normally enhanced pituitary gland. The margin was ill-defined in seven cases and well-defined in three. Eight cases had pituitary height 7 mm or more. Upper surface of the pituitary gland was convex upward in five cases, flat in four and concave in two. Deviation of pituitary stalk was found in seven cases. Bony changes of sellar floor were recognized in three cases. There was a tendency that serum GH level increased with the increment of the size of adenoma. Serum GH levels in adenomas with ring enhancement were lower than those in the homogeneously enhanced adenomas of similar size. One case with marked enhancement showed the highest GH level among all adenomas of the presented series.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoma↗
PubMed1985

Synergistic stimulation of VIP/PHM-27 gene expression by cyclic AMP and phorbol esters in human neuroblastoma cells.

The effects of dibutyryl cAMP (Bt2cAMP) and phorbol esters such as 12-O-tetradecanoylphorbol-13-acetate (TPA) and phorbol-12,13-didecanoate (PDD) on VIP/PHM-27 gene expression in human neuroblastoma cells in culture were investigated. Bt2cAMP and phorbol esters increased the VIP/PHM-27 mRNA level by about 9- and 4-fold, respectively. In the presence of both Bt2cAMP and phorbol esters, the VIP/PHM-27 mRNA level increased by about 36-fold. The intracellular cAMP level was essentially unaffected by phorbol esters. The VIP/PHM-27 gene dosage was unchanged by Bt2cAMP and phorbol esters. The results suggest that cAMP and phorbol esters synergistically induce the VIP/PHM-27 gene expression through independent pathways.

1-Methyl-3-isobutylxanthine↗
PubMed1985

High-performance liquid chromatography of coenzyme Q-related compounds and its application to biological materials.

A convenient and precise method for the separation and determination of coenzyme Q (CoQ)-related compounds (CoQ homologues, plastoquinone-9, ubichromenol-9, etc.) was developed using high-performance liquid chromatography (HPLC). All compounds tested were separated using a reverse-phase column with a suitable mobile phase and detected at a wavelength of 275 nm. CoQ extracts in plasma and erythrocytes were purified by thin-layer chromatography prior to HPLC analysis, but such purification was not necessary when determining CoQ in urine and tissues. Hydroquinone forms of CoQ existing in animal tissues were oxidized to the corresponding quinone forms with potassium hexacyanoferrate(III). This HPLC method was applied satisfactorily to the determination of the contents of CoQ homologues in human and animal samples. CoQ10 was the only homologue detected in human samples, and CoQ8, CoQ9 and CoQ10 were native homologues of CoQ in rat tissues. Ubichromenol-9 and plastoquinone-9 were not detected in these samples.

Adult↗
PubMed1985

Therapeutic effect of taurine in congestive heart failure: a double-blind crossover trial.

In a double-blind, randomized, crossover, placebo-controlled study, we investigated the effects of adding taurine to the conventional treatment in 14 patients with congestive heart failure for a 4-week period. Compared with placebo, taurine significantly improved the New York Heart Association functional class (p less than 0.02), pulmonary crackles (p less than 0.02), and chest film abnormalities (p less than 0.01). A benefit of taurine over placebo was demonstrated when an overall treatment response for each patient was evaluated on the basis of clinical examination (p less than 0.05). No patient worsened during taurine administration, but four patients did during placebo. Pre-ejection period (corrected for heart rate) decreased from 148 +/- 14 ms before taurine treatment to 137 +/- 12 ms after taurine (p less than 0.001), and the quotient pre-ejection period/left ventricular ejection time decreased from 47 +/- 9 to 42 +/- 8% (p less than 0.001). Side effects did not occur in the patients during taurine. The results indicate that addition of taurine to conventional therapy is safe and effective for the treatment of patients with congestive heart failure.

Administration, Oral↗
PubMed1985

Astroblastoma of pure type.

A rare case of astroblastoma of the pure type occurring in the left occipital lobe of a 54-year-old female is reported. The predominant histologic feature was that of perivascular pseudorosettes. The tumor tissues were not stained by the Mallory's phosphotungstic acid-hematoxylin, but the perikarya of some tumor cells were positively stained for the glial fibrillary acidic protein.

Astrocytoma↗
PubMed1985

Histologic study of normal rat brain tissue after neodymium-yttrium aluminum garnet laser irradiation. I. Cerebral hemisphere.

We report a histologic study of normal rat brain tissue after neodymium-yttrium aluminum garnet laser irradiation. Morphological changes occurred at a maximum depth of 5 mm after 60-W, 1-second exposure, at a 2-mm distance between the optical fiber tip and the brain surface. Polymorphonuclear leukocyte infiltration into the irradiated area was observed 48 hours after irradiation. After 72 hours, macrophages and fibroblasts appeared; their number increased thereafter. At 1 month, tissue defects attributable to neodymium-yttrium aluminum garnet laser irradiation were small. Gliotic changes were rarely seen. We conclude that 60-W irradiation is harmful to young rats but not to adult rats.

Animals↗
PubMed1985

Histologic changes in rat brain tissue caused by neodymium-yttrium aluminum garnet laser irradiation. II. Cerebellum.

Histologic changes after neodymium-yttrium aluminum garnet laser irradiation were evaluated in the rat cerebellum. Irradiation of 60 W (corresponds to 45.2 W/mm2) to the posterior fossa was dangerous even in adult rats, although this value was safe for the rat cerebral hemisphere as previously reported. The histologic changes caused by neodymium-yttrium aluminum garnet laser irradiation were similar to those caused by thermal energies. To the adult rat cerebellum, 45 W (35.2 W/mm2) can safely be applied. For the further use of the neodymium-yttrium aluminum garnet laser in neurosurgery, our findings should be taken into consideration.

Animals↗
PubMed1985

Induction of rat pancreatic B-cell tumors by the combined administration of streptozotocin or alloxan and poly(adenosine diphosphate ribose) synthetase inhibitors.

Streptozotocin and alloxan were administered to Wistar rats in combination with poly(adenosine diphosphate ribose) synthetase inhibitors. Ten to 16 months after the injection of streptozotocin (50 mg/kg body weight i.v.) and 3-aminobenzamide (345 mg/kg i.v.), streptozotocin (50 mg/kg) and nicotinamide (350 mg/kg i.p.), streptozotocin (50 mg/kg) and picolinamide (250 mg/kg i.p.), alloxan (40 mg/kg i.v.) and nicotinamide (350 mg/kg), alloxan (40 mg/kg) and 3-aminobenzamide (345 mg/kg), and alloxan (40 mg/kg) and picolinamide (250 mg/kg), pancreatic islet cell tumors developed in 100, 98, 60, 26, 22, and 20% of surviving rats, respectively. However, after the single injection of streptozotocin and alloxan, islet cell tumors developed in 42 and 11% of surviving rats, respectively. The tumors were rich in B-granules on electron micrographs and contained as large amounts of proinsulin messenger RNA as normal pancreatic islets. The results indicate that poly(adenosine diphosphate ribose) synthetase inhibitors enhance the tumorigenic effect of streptozotocin and alloxan on islet B-cells.

Adenoma, Islet Cell↗
PubMed1985

[Treatment of primary empty sella with intractable headache via the transsphenoidal approach].

Two cases of primary empty sella with intractable headache were treated via the transsphenoidal approach. One patient was a fifty-three-year-old female with right upper nasal quadrantanopsia and intractable retrobulbar pain and the other was fourty-six-year-old female with continuous retrobulbar pain with a history of transient right temporal hemianopsia. Both cases were diagnosed by metrizamide CT cisternography. They had normal endocrinological functions. They did not respond to drug therapy and were treated surgically. In each case, the dura mater of the floor of the sella was elevated with lyophilized human dura mater and bone fragments obtained during the procedure. In the former case, significant improvement of visual field defect was not obtained but the retrobulbar pain disappeared completely after the operation. In the latter case which had intractable headache for six months, the symptom disappeared just after the operation. Until now, retroorbital pain has not recurred in both cases for several months. Primary empty sella has been considered to be a benign condition except in some cases with CSF rhinorrhea or with visual disturbance. Headache which is often accompanied to primary empty sella has rarely been treated surgically because it is difficult to know whether the headache is related to the empty sella or not. Another reason may be that there is few available data concerning to the efficacy of surgical treatment. Headache caused by stretching of the dura of the floor of the sella is usually frontal or retrobulbar, continuous, profound and intractable.(ABSTRACT TRUNCATED AT 250 WORDS)

Empty Sella Syndrome↗
PubMed1985

[Estrogen-induced pituitary tumors--in relation to the changes in the pituitary gland after estrogen withdrawal].

Pituitary tumors were induced in female rats of Wistar strain by administration of estradiol valerate (E2) and the effect of estrogen withdrawal on E2-induced tumors were studied to elucidate the nature of the induced tumors. Ten mg of E2 was administered to 100 rats intraperitoneally once every 2 weeks, totally four times. Experimental animals were sacrificed at 1 week before, 2, 6, 10, and 14 weeks after stopping injection of E2. The incidence of pituitary tumor and hyperplasia (Table 1). Pituitary glands in each animals were examined and were classified into three groups, namely pituitary tumor, hyperplasia, and normal gland according to histological findings. The incidence of pituitary tumors was highest in rats sacrificed 6 weeks after E2 withdrawal. Pituitary tumors became less frequent and hyperplasias and normal glands became more frequent in rats sacrificed thereafter. Pituitary weight (Table 2, Fig. 1) Irrespective of timing of sacrifice, the weight of pituitary gland (mean +/- SE) was 134 +/- 70 mg in the group which were judged as having a pituitary tumor, 38 +/- 17 mg in the hyperplasia group, and 17 +/- 5 mg in the normal group, respectively. Pituitary weight of control rats were 12 +/- 3 mg. The tumor group had a significantly heavier pituitary weight than hyperplasia and normal groups (p less than 0.01). In each group, there was no significant difference of pituitary weights between animals sacrificed at different intervals after E2 withdrawal.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoma↗
PubMed1985

[Clinical analysis of large and/or invasive pituitary adenomas].

To establish a more reasonable therapeutic guide line for large and/or invasive pituitary adenomas, 257 cases of pituitary adenoma were analyzed. Among 83 cases with slight or moderate suprasellar extension (Wilson's Grade II-A & B) in the pre-CT era, 57 patients were alive at the time of follow-up (mean follow-up period: 12.7 years). Death of unspecified causes other than cancer, myocardial infarction, etc. were reported in nine patients. Among 60 cases of Grade II-A & B in the post-CT era, 59 patients were alive (mean follow-up: 3.4 years). Comparing these groups, cases with huge suprasellar extension (Grade C) had much worse prognosis. Only two patients were alive among 14 cases of Group C in the pre-CT era. Seven cases of death with unspecified causes were reported. In the 13 cases of Group C in the post-CT era, 12 patients were alive but at least four of them were severely handicapped. In 10 cases with sphenoid invasion (Grade IV) in the pre-CT era, only two were alive. In the group of Grade IV in the post-CT era, one patient died and three patients were operated repeatedly. Severe complications of irradiation therapy occurred in seven patients (mean interval: 6.6 years) among 120 cases of irradiated pituitary adenomas in every category. Among six cases with histological malignancy, three were operated repeatedly; among the latter group, two patients died and the third showed intracranial metastases. The present data indicate that large and/or invasive pituitary adenomas have a pessimistic prognosis, although adenomas with mild or moderate simple suprasellar extension have fairly good prognosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoma↗