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Biomedical subjects

M Tamaki

Publications and source records attributed to M Tamaki.

At least 19 recordsLinked to original sources
PubMed1996

Prognostic significance of Ki-67 labeling indices obtained using MIB-1 monoclonal antibody in patients with supratentorial astrocytomas.

BACKGROUND: Identification of the prognosis of patients with gliomas is important for selecting and evaluating the effectiveness of treatment. The aim of this study was to evaluate the Ki-67 labeling index (LI) using the newly generated MIB-1 monoclonal antibody (MoAb) as a prognostic indicator for patients with astrocytomas. METHODS: Ki-67 immunohistochemistry was performed on paraffin sections to estimate the growth potential of 72 supratentorial astrocytomas using the MIB-1 MoAb after hydrated autoclaving treatment. Multivariate analysis using the Cox proportional hazard stepwise model was used to evaluate the influence of Ki-67 LI, as well as other prognostic factors, on the duration of survival of patients with supratentorial astrocytomas. RESULTS: The mean Ki-67 LI was 3.8% (+/- 2.7%; standard deviation [SD]) in Grade 2 gliomas (n = 19), 18.4% (+/- 9.7% SD) in Grade 3 gliomas (n = 25), and 31.6% (+/- 12.9% SD) in Grade 4 gliomas (n = 28). Multivariate survival analysis showed that histologic grade, Ki-67 LI, and Karnofsky performance status (KPS) score before and after treatment were independent, statistically significant prognostic factors for patients with all grades of astrocytomas. In high grade lesions, Ki-67 LI, tumor location (superficial vs. deep), and KPS score after treatment were significant prognostic variables, whereas histologic grade did not meet the significance level for entry into the stepwise model. CONCLUSIONS: These results indicate that the Ki-67 LI obtained using MIB-1 MoAb is an important and practical tool for estimating biologic behavior of gliomas, as well as for predicting survival.

Adolescent↗
PubMed1996

A stable Escherichia coli-mycobacteria shuttle vector 'pSO246' in Mycobacterium bovis BCG.

The most widely used plasmid vector system in mycobacteria is based on pAL5000 from Mycobacterium fortuitum. The derivatives of the pAL5000-based shuttle vectors between Escherichia coli and mycobacteria, which we have utilized to secrete recombinant antigens, were generated. The stability of the vectors was assessed in Mycobacterium bovis BCG (BCG). The plasmid vector pSO246 was stable in BCG for at least 50 generations.

Bacterial Proteins↗
PubMed1995

Molecular evolution of a class C beta-lactamase extending its substrate specificity.

Enterobacter cloacae GC1, a clinical strain isolated in 1992 in Japan, was found to produce a chromosomal class C beta-lactamase with extended substrate specificity to oxyimino beta-lactam antibiotics, significantly differing from the known E. cloacae beta-lactamases such as the P99 beta-lactamase. The 1560 nucleotides including the GC1 beta-lactamase gene were sequenced, and the amino acid sequence of the mature enzyme comprising 364 amino acids was deduced. A comparison of the amino acid sequence with those of known E. cloacae beta-lactamases revealed the duplication of three amino acids at positions 208-213, i.e. Ala-Val-Arg-Ala-Val-Arg. This duplication was attributed to a tandem duplication of a 9-nucleotide sequence. The chimeric beta-lactamases produced by the chimeric genes from the GC1 and P99 beta-lactamase genes indicated that the extended substrate specificity is entirely attributed to the 3-amino acid insertion. Two mutant beta-lactamases were prepared from P99 beta-lactamase by site-directed mutagenesis, i.e. an Ala-Ala-Ala sequence was inserted before or after the native Ala-Val-Arg at positions 208-210. These mutant enzymes revealed that the Ala-Val-Arg located from positions 211 to 213 in the GC1 beta-lactamase are the newly inserted residues, and this phenomenon is independent of the characteristics of the amino acids inserted.

Amino Acid Sequence↗
PubMed1995

Persistent pure verbal amnesia and transient aphasia after left thalamic infarction.

A 57-year-old right-handed man suffered persistent pure verbal amnesia (PPVA) and transient aphasia after left thalamic infarction. A neuroanatomical study with magnetic resonance imaging to identify the site of the lesion showed destruction of the internal medullary lamina (IML), mammillothalamic tract (MTT), the ventrolateral nucleus (VL) and the lower one-third of the medial nucleus. As regions critical for PPVA are unknown, we reviewed the cases of PPVA after left thalamic infarction reported in the literature. These suggest that confined destruction of the IML, MTT and VL in the left thalamus can produce PPVA.

Anomia↗
PubMed1995

Cell adhesion molecules acting between C6 glioma and endothelial cells.

The interactions between tumor cells and endothelium play a key role in the process of tumor growth, local invasion, and distant metastasis. In the present study, we examined the adhesion of C6 glioma cells to bovine endothelial cell (EC) monolayers and defined the cell adhesion molecules acting between these cells. Pretreatment of the EC monolayer with cytokines, tumor necrosis factor (TNF)-alpha, interleukin (IL)-1 beta, and interferon (INF)-gamma, significantly increased the adhesion of C6 glioma cells to the EC monolayer. The effect lasted more than 24 hours and was protein-synthesis dependent. The adhesion of C6 glioma cells to TNF-activated ECs was blocked by the monoclonal antibody to the intercellular adhesion molecule-1 (ICAM-1) or beta 2 integrin, whereas that of melanoma cells was not. These findings provide evidence that ICAM-1 and beta 2 integrin function as inducible cell surface molecules that can support the adhesion of C6 glioma cells to ECs, and may contribute to the characteristic growth of glial tumors in vivo.

Animals↗
PubMed1995

Immunofluorescence study of immune complexes in polymyalgia rheumatica.

Two elderly patients with polymyalgia rheumatica (PMR), one with and the other without temporal arteritis (TA), are presented. Immunofluorescence study of muscle biopsy specimens showed IgG, IgA, and fibrinogen deposits in the perifascicular area in the perimysium. This finding suggests that immune complexes play a role in the pathogenesis of this condition and that the pathophysiology of PMR involves an interstitial inflammatory process.

Angiography↗
PubMed1995

Induction of Fos protein in the rat hypothalamus elicited by insulin-induced hypoglycemia.

To evaluate the responses to insulin-induced hypoglycemia of neurons in vivo, we studied Fos protein induction in the brain by means of immunohistochemistry. The induction of Fos protein was maximum after the first injection of insulin for 3 h. This induction was found in the parvocellular division of paraventricular nucleus (PVN), the periventricular, dorsomedial and arcuate nuclei and the lateral hypothalamic area of the hypothalamus. These findings show the activation of specific subsets of neurons in areas of the hypothalamus following hypoglycemic stimulation.

Animals↗
PubMed1995

Resistance of growth hormone secretion to hypoglycemia in the mouse.

Although previous studies have demonstrated that acute hypoglycemia inhibits growth hormone (GH) secretion due to stimulation of hypothalamic somatostatin (SS) neurones in the rat, the effect of hypoglycemia on GH secretion has not yet been elucidated in the mouse. In this study, the effects of insulin-induced hypoglycemia on mouse GH secretion, hypothalamic c-fos expression, GH-releasing hormone (GRH) and SS mRNA levels were investigated in conscious male mice. Seven days after implantation of chronic atrial catheters, blood samples were taken every 20 min from 1200-1600 h under unrestrained conditions. Insulin was administered iv every 20 min from 1200-1240 h to induce moderate hypoglycemia (MH) and severe hypoglycemia (SH), respectively. Expression of hypothalamic c-fos protein was examined 30 min and 60 min after induction of hypoglycemia by immunohistochemistry. Hypothalamic GRH and SS mRNA levels were examined 1 h and 3 h after induction of hypoglycemia by Northern blot analysis. The lowest mean plasma glucose levels after insulin injections were 49.1 +/- 4.1 mg/dl and 34.2 +/- 5.6 mg/dl in conscious mice, respectively. However, pulsatile GH secretion was not significantly altered in either group. Although both MH and SH markedly stimulated c-fos expression in specific hypothalamic nuclei including the paraventricular nucleus, they did not induce c-fos protein in the periventricular nucleus. Neither MH nor SH altered hypothalamic GRH or SS mRNA levels. These results suggest that hypoglycemia does not activate SS neurons which inhibit GH secretion in the mouse.

Animals↗
PubMed1995

Role of ring size on the secondary structure and antibiotic activity of gramicidin S.

In order to investigate the contribution of ring size to the secondary structure and antibiotic activity of gramicidin S, many analogs consisting of 6, 7, 8, 9, 11, 12, 13, and 14 amino acid residues were synthesized. In the analogs with smaller ring sizes than that of gramicidin S, only des-Val1-, des-Leu3- and des-Pro5-gramicidin S showed weak activity against the gram-positive micro-organisms tested. On the other hand, all analogs having larger rings, in which L- or D-Leu residues were inserted, were active. The activity of the analogs consisting of 10, 11 and 12 amino acid residues was stronger than those of the analogs with other ring sizes, and the activity of endo-Leu2a-gramicidin S against S. epidermidis SP-al-1 and B. subtilis ATCC 6633 was twice of that of gramicidin S.

Amino Acid Sequence↗
PubMed1995

Suppression of episodic growth hormone secretion in streptozotocin-induced diabetic mice: time-course studies on the hypothalamic pituitary axis.

To elucidate the roles of the hypothalamic peptides, GH-releasing hormone (GRH) and somatostatin (SRIH), potentially responsible for altered GH dynamics in diabetes, we studied the time courses of their changes in level associated with altered GH secretion in streptozotocin (STZ)-induced diabetic mice. Diabetic mice were used at 4, 7, and 14 days after STZ injection for analyses of 1) GH secretion in vivo, 2) hypothalamic GRH and SRIH messenger RNA (mRNA) levels, 3) pituitary GH mRNA and protein contents, and 4) pituitary GH response to GRH in vitro. GH secretion was completely suppressed 7 and 14 days after STZ injection. The hypothalamic GRH mRNA level was reduced to 59.8%, 61.2%, and 48.5% of control values at 4, 7, and 14 days, respectively. In contrast, the hypothalamic SRIH mRNA level was not altered at all of these time points. Pituitary GH mRNA and protein contents were significantly reduced to 70.2% and 61.5% of those in controls, respectively, only at 14 days. Pituitary GH responses to GRH at three doses (10, 50, and 250 nM) in vitro were remarkably increased at 4, 7, and 14 days. These findings indicate that the diabetic state rapidly and primarily inhibits hypothalamic GRH gene expression without affecting SRIH. A persistent decrease in hypothalamic GRH tone has been suggested to result in inhibition of GH synthesis in the pituitary. Enhancement of GH responsiveness to GRH may be due to the up-regulation of GRH receptors in the pituitary.

Animals↗
PubMed1995

Inhibitory effects of interleukin-1 on growth hormone secretion in conscious male rats.

Although various pathophysiological effects of interleukin (IL) on the CRF-ACTH-adrenal axis and gonadotropin secretion have been studied extensively, the effects of IL on GH secretion still remain to be elucidated. We investigated the possible effects of IL on GH secretion in six groups of conscious rats. In four groups, IL was administered by continuous iv infusion and in the other two, by intracerebroventricular injection. Saline-treated rats served as controls for these groups. Sequential blood sampling was performed every 20 min in all groups, and the plasma GH concentration was determined by RIA. The expression of hypothalamic c-fos protein in a separate group was examined by immunohistochemistry. Continuous infusion of both IL-1 alpha and IL-1 beta (10 ng/min) significantly inhibited GH surges. The plasma IL-1 level was elevated to 2-3 ng/ml. Continuous iv infusion of IL-2 and IL-6 had no effect on GH secretion. The intracerebroventricular injection of both IL-1 alpha and IL-1 beta significantly inhibited GH surges, and the inhibitory effect was much greater for IL-1 beta than for IL-1 alpha. Continuous iv infusion of IL-1 beta markedly stimulated c-fos expression in specific hypothalamic nuclei, particularly in the paraventricular nucleus. These findings suggest that, in the rat, IL-1 inhibits GH secretion through its peripheral and central actions.

Animals↗
PubMed1995

Immunohistochemical detection of progesterone receptors and the correlation with Ki-67 labeling indices in paraffin-embedded sections of meningiomas.

Female sex steroids may play a role in the proliferation of meningiomas. We investigated the progesterone receptor (PgR) immunoreactivities and the Ki-67 labeling indices in the formalin-fixed, paraffin-embedded sections of meningiomas from 39 patients. After autoclave pretreatment of the sections (which were immersed in a citrate buffer), the sections were incubated with the monoclonal antibody for the PgR and the MIB-1 monoclonal antibody for the Ki-67 antigen. In the meningiomas studied, the immunoreactivity for the PgR was moderately to strongly positive in 51%, weakly positive in 21%, and negative in 28%. The nuclear staining for the PgR was clear, and no tumors were positive for the estrogen receptor. The Ki-67 labeling indices of the PgR-positive meningiomas (mean +/- standard deviation, 2.35 +/- 2.12%) were significantly lower than those of the PgR-negative meningiomas (6.53 +/- 4.83%) (P < 0.05). Two meningiomas that had recurred more than once showed high Ki-67 labeling indices and negative immunostaining for the PgR. These findings indicate that the PgR status may be closely related to the growth potentials of the meningiomas. Our results confirm that the immunodetection of the PgR and the Ki-67 antigen on the paraffin sections of meningiomas provides a practical tool for estimating the biological behavior of the meningiomas.

Adult↗
PubMed1995

Unusual recurrence pattern in peritorcular meningioma--case report.

A 45-year-old female presented with a recurrent peritorcular meningioma. The recurrence was very unusual as the tumor arose from the confluens sinuum and extended to the left jugular bulb completely within the sinuses, obstructing the venous outflow. However, there were no clinical symptoms or neurological abnormalities, due to the development of collateral circulation. The possibility of intrasinus recurrence should always be considered in patients with tumor invasion to sinus walls, even if the patient has no clinical symptoms or neurological abnormalities.

Cranial Sinuses↗
PubMed1995

[Two cases of cavity formation in prostatic urethra after transurethral microwave thermotherapy (TUMT) with Prostatron].

The Prostatron device, developed by Dr. Devonec, provides microwave heating of the prostate and simultaneous conductive cooling of the urethra. Treatment with Prostatron (transurethral microwave thermotherapy: TUMT) of BPH can be performed in a single session, and the urethra, the rectum and the surrounding tissue are protected with the temperature monitoring system. TUMT with Prostatron may be more suitable for a small adenoma with mild symptoms than a large adenoma with severe symptoms, because objective improvement is rarely observed compared with subjective improvement. We have treated 40 cases of BPH with Prostatron (Prostasoft 2, max. energy: 50 watt, max. urethral temperature: 44.5 degrees C, max. rectal temperature: 42.5 degrees C) since March 1993. Among them, there were 2 cases of large cavity formation involving the prostatic urethra. With cavity formation, TUMT may have its place in the treatment of a large adenoma with severe urinary symptoms, but loses its advantage in the prevention of persistent urinary infection and retrograde ejaculation, especially in the treatment of a small adenoma in a younger patient with mild urinary symptoms. It is unknown why such cavity formation occurred only in 2 patients among 40 equally treated cases, but the causes of cavity formation and safety of TUMT should be evaluated again, even though no injury to the rectum and the external urethral sphincter were detected. We report these 2 cases, and causes of cavity formation and discuss the prospects of TUMT.

Aged↗
PubMed1995

[Chronic inflammatory demyelinating polyneuropathy associated with chronic liver disease due to type B and type C hepatitis virus].

A patient with chronic inflammatory demyelinating polyneuropathy (CIDP) associated with type B and type C hepatitis virus infection is reported. A 54-year-old female who had a blood transfusion at the age of 31 years was diagnosed as a carrier of hepatitis B virus at the age of 43. Liver dysfunction was first noted in 1987 and gradually grew worse year by year. Beginning in early June 1992, the patients general fatigue became worse, her serum GOT and GPT levels became elevated, and she complained of a tingling sensation in her arms and legs. Neurological examination revealed moderate sensory disturbance of the glove-and-stocking type in all of her extremities. Deep tendon reflexes were all diminished. Hepatitis C antibody was detected in the serum at this time. On June 12, 1993, progression of her sensory disturbance was found to be associated with generalized muscle weakness. Cerebrospinal fluid studies showed increased protein without pleocytosis. Motor nerve conduction studies revealed marked prolongation of terminal latencies, reduction of conduction velocities, and abnormal temporal dispersion of the motor potentials. No sensory potentials could be evoked at any of the sites stimulated. Sural nerve biopsy showed segmental demyelination and severe loss of large myelinated fibers as well as some onion bulb formation. A diagnosis of CIDP was made. Treatment with corticosteroids was started, but there was little improvement in neurological function. The liver dysfunction progressed further and ultimately the patient died of hepatic failure. An autopsy demonstrated liver cirrhosis, but no malignant tumors were evident.(ABSTRACT TRUNCATED AT 250 WORDS)

Chronic Disease↗
PubMed1995

[A case of lung metastasis from renal cell carcinoma showing complete response by a combination chemotherapy with methotrexate, vinblastine and pepleomycin (MVP)].

A 69-year-old woman visited our hospital with complaints of low grade fever and general fatigue in October 1990. Computed tomography (CT), ultrasonogram, and renal arteriography showed left renal tumor and she was diagnosed with renal cell carcinoma (T2M0N0). Left radical nephrectomy was performed in December 12, 1990. After operation, 3 x 10(6) unit per day of IFN-alpha were administered three times per week. She complained of low grade fever and general fatigue in June, 1991. CT showed left lung metastasis (phi 3 cm). She was given combined chemotherapy (MVP: methotrexate, vinblastine, pepleomycin). After 2 courses, lung metastasis decreased and after 4 courses, lung metastasis was not shown by CT in December, 1992. No evidence of relapse was shown by CT in June, 1994.

Aged↗