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Biomedical subjects

M Koga

Publications and source records attributed to M Koga.

At least 217 records · Page 12Linked to original sources
PubMed1997

The measurement of blood flow parameters with deuterium stable isotope MR imaging.

METHODS: Because there are no radioactive hydrogen isotopes which can be used for clinical examinations, deuterium as a non-radioactive, freely diffusible tracer has some advantages compared with the radioactive tracers in the measurement of blood flow parameters. A non-invasive technique to estimate the mean tissue blood flow parameter in vivo was developed by using deuterium nuclear magnetic resonance (NMR) imaging in rat. We obtained the NMR signal changes from deuterium NMR images in nine male Wister rats after intravenous injection of D2O and applied exponential curve fitting analyses to calculate blood flow parameters of the brain, heart and skeletal muscle. RESULTS: While fitting the reducing of the monoexponential function yielded a blood flow parameter of 27.9 +/- 1.6 ml/min/100 g tissue weight for the brain and 46.7 +/- 3.7 ml/min/100 g tissue weight for the heart, fitting the early reducing of the signal intensity of the biexponential function yielded a blood flow parameter of 95.6 +/- 10.9 ml/min/100 g tissue weight for the brain and 108.0 +/- 13.1 ml/min/100 g tissue weight for the heart. The mean muscle blood flow parameter determined by the monoexponential uptake function was 43.8 +/- 7.3 ml/min/100 g tissue weight. CONCLUSIONS: The blood flow parameter measurement by means of an imaging coil for deuterium is less invasive and reflects the mean tissue blood flow parameter for the entire tissue sample more homogeneously than spectroscopic monitoring.

Animals↗
PubMed1997

Amlodipine lowers blood pressure without increasing sympathetic activity or activating the renin-angiotensin system in patients with essential hypertension.

OBJECTIVE: Recent clinical studies suggest that the reflex increase in sympathetic nervous activity accompanying a reduction in blood pressure may contribute to the untoward effects of dihydropyridine calcium antagonists. The aim of this study was to examine whether plasma noradrenaline levels and renin activity are increased with the reduction of blood pressure during the initial phase of administration of the long-acting dihydropyridine calcium antagonist amlodipine. METHODS: The effects of amlodipine on ambulatory blood pressure and on diurnal variations in plasma noradrenaline and renin activity were examined 1, 4, and 7 days after the start of amlodipine administration in eight inpatients with essential hypertension. RESULTS: The 24-h mean systolic and diastolic blood pressure on day 7 was significantly lower than it was 1 day before the start of treatment. There was no change in the mean heart rate. The mean trough to peak ratios of systolic and diastolic blood pressure of seven patients were 61% and 71%, respectively. Diurnal patterns of plasma noradrenaline levels and renin activity 1, 4, and 7 days after the start of amlodipine administration were unchanged. CONCLUSION: The antihypertensive effects of amlodipine were of slow onset and long duration and were not accompanied by an increase in sympathetic activity or activation of the renin-angiotensin system.

Aged↗
PubMed1997

Immunosuppressant pharmacodynamics on lymphocytes from healthy subjects and patients with chronic renal failure, nephrosis, and psoriasis: possible implications for individual therapeutic efficacy.

BACKGROUND: In organ transplantation, patients with peripheral blood mononuclear cells (PBMCs) that exhibit resistance to cyclosporine (INN, ciclosporin) or glucocorticoids in vitro are refractory to therapy based on these drugs in vivo. However, detection or distribution of the resistant patients with immunologic disorders remains to be documented. METHODS: Drug sensitivity tests were performed with PBMCs from four subject groups: 69 healthy subjects, 100 patients with chronic renal failure, 38 patients with nephrosis, and 51 patients with psoriasis. The values for the concentration that produces 50% lymphocyte-mitosis inhibition (IC50) of the drugs on PBMC blastogenesis were estimated, and individual variations or group differences in the IC50 values were examined. RESULTS: The median cyclosporine IC50 values of the four subject groups were similar, but large individual deviations in the IC50 values were observed. Individual differences in prednisolone IC50 values were spread from 1 to 3500 ng/ml. When compared with healthy subjects, a significantly large number of the patients with chronic renal failure group exhibited low responses to prednisolone (p < 0.04). In contrast, no significant difference in the methylprednisolone IC50 was observed among the groups. Normal upper thresholds for IC50 values of these drugs were estimated from the mean + 2 standard deviations (SD) of the IC50 values of healthy PBMCs, and the patients with IC50 values above these levels were considered to be resistant. The incidence of resistant patients with nephrosis or psoriasis was similar to that of healthy subjects; however, the incidence of cyclosporine- or prednisolone-resistant subjects with chronic renal failure was significantly higher (p < 0.04). Significant correlations between PBMC sensitivity to cyclosporine in vitro and clinical efficacy of the drug in vivo were observed in renal transplant recipients and in patients with psoriasis. CONCLUSIONS: A large subset of patients with chronic renal failure showed PBMC resistance to cyclosporine and prednisolone. Hyperresistant patients have a high risk of being refractory to immunosuppressive therapy with one of these drugs. Alternative treatment should be considered according to the individual drug-sensitivity data.

Adult↗
PubMed1997

Comparison between magnetization transfer contrast and fast spin-echo MR imaging of degenerative disease of the cervical spine at 0.3 T.

We compared magnetization transfer contrast (MTC) with gradient recalled echo (GRE) magnetic resonance imaging (MRI) and fast spin-echo (FSE) MRI of the degenerative cervical spine at 0.3 T. Fifty patients with suspected degenerative disease of the cervical spine were prospectively evaluated. Multislice sagittal and axial images of the cervical spine were obtained using MTC GRE sequence [repetition time (TR)/echo time (TE)/flip angle = 750/23/25 degrees] and FSE sequence with peripheral gating (TR/effective TE = 2000-4000/120). Quantitatively, FSE showed higher signal-to-noise ratio and superior disk contrast between normal and degenerative disks, while MTC images showed superior contrast-to-noise ratio for the cerebrospinal fluid (CSF) versus cord and superior CSF homogeneity. In qualitative analysis, similar results were obtained. In conclusion, FSE and MTC GRE sequences are MRI techniques of imaging the cervical spine that have different characteristics and supplement each other in the diagnostic imaging of degenerative disease of the cervical spine.

Adult↗
PubMed1997

Multiple pulmonary nodules in association with pyoderma gangrenosum.

This report describes a patient with extensive pyoderma gangrenosum in whom there were co-existent lung abnormalities. The patient's X-ray showed peripherally sited multiple pulmonary lesions bilaterally. A lung biopsy showed chronic non-specific inflammatory changes with neutrophil and lymphocyte infiltration which were similar to the skin lesions. This case was diagnosed as multiple aseptic nodules in pyoderma gangrenosum. The pulmonary infiltrative shadows were controlled only with prednisolone treatment. Steroid therapy is considered to be the first choice to control pulmonary lesions of this disease.

Anti-Inflammatory Agents↗
PubMed1997

Interleukin-6 secreting phaeochromocytoma associated with clinical markers of inflammation.

Phaeochromocytomas have been shown to produce not only catecholamines but other neuropeptides and hormones, with a variety of clinical manifestations. We report a 70-year-old female patient with phaeochromocytoma exhibiting sustained hypertension, low-grade fever, thrombocytosis, and elevated levels of plasma fibrinogen and C-reactive protein. Serum interleukin (IL)-6 levels were significantly elevated, whereas serum IL-1 alpha and IL-1 beta were not detectable. After surgical removal of the tumour, hypertension and low-grade fever disappeared, and the laboratory finding including serum IL-6 concentrations became normal. Immunohistochemical study of the tumour showed positive staining for IL-6. Culture of the resected tumour revealed the production of large amounts of IL-6. It is suggested that IL-6 secreted by the tumour was responsible for some of the clinical manifestations in this patient.

Adrenal Gland Neoplasms↗
PubMed1997

Human hepatic carbohydrate metabolism. Dynamic observation using 13C MRS without proton decoupling.

PURPOSE: Dynamic natural-abundance 13C MR spectroscopy (MRS) studies without proton decoupling were performed in the human liver using commercial 1.5 T MR equipment. MATERIAL AND METHODS: A single tuned custom-made circular surface coil with an OD of 20 cm operating at 16.04 MHz was used for the 13C study. Seventy-five grams of glucose dissolved in water was administered for the natural-abundance 13C-MRS dynamic study which lasted for approximately 40 to 60 min. Data acquisition was broken into 20-min and 1.7-min blocks. Localized proton shimming with a whole-body coil was performed with sufficient volume to include the observing area of the surface coil; the line width of the water signal was less than 20 Hz. RESULTS AND CONCLUSION: The glucose and glycogen spectra were clearly visible at 80 to 120 ppm after oral administration of the glucose solution. These data demonstrate that dynamic hepatic carbohydrate metabolism can be observed with commercially available MR equipment. Given that the human hepatic glycogen pool reaches maximum level within less than 10 min, this technique should provide a direct diagnosis of hepatic carbohydrate metabolic disorders.

Administration, Oral↗
PubMed1997

Relationship between levels of soluble interleukin-2 receptors and the types and activity of vitiligo.

Levels of serum-soluble interleukin-2 receptors (serum sIL-2R) are thought to indicate the activation of immunocompetent cells, mainly lymphocytes. Elevated levels of serum sIL-2R have been observed in various infectious and autoimmune diseases and also after organ transplantation. It has been hypothesized that autoimmune mechanisms are involved in the pathogenesis of vitiligo. Therefore, we studied serum sIL-2R levels in relation to disease types and activity of vitiligo. We used sera separated from venous blood samples from 12 patients with dermatomally distributed type B vitiligo, 17 patients with non-dermatomally distributed type A vitiligo during the active stage, 9 patients with type A vitiligo during the inactive stage, and 12 normal control subjects. Serum sIL-2R levels were similar in type B vitiligo patients and the controls but were significantly elevated in patients with active type A vitiligo compared with controls and inactive type A vitiligo patients. It is suggested that the immune system is activated in patients with type A vitiligo during the active stage and that autoimmune mechanisms may play a role only in type A vitiligo.

Autoimmunity↗
PubMed1997

Evaluation of acceleration plethysmograms in dermatology--efficacy of lipo PGE1 preparations against herpes zoster and neuralgia following herpes.

Reports published in recent years indicate that administration of lipo PGE1 is effective against herpes zoster and neuralgia following herpes. However, there are presently no standards to objectively assess efficacy. We therefore looked into the possibility of achieving this goal by using an acceleration plethysmograph. The results showed a significant difference in the rate of change of pulse waves after initiation of drip infusion as compared to before drip infusion among the effective group, the control group, and the non-effective group. This method appears to be useful to objectively assess both the analgesic effects of lipo PGE1 and the efficacy of drugs in general, based on data analysis. Our results suggest that investigations using this method may be able to predict the therapeutic effects of vasodilators and analyze hemodynamic disorders of the skin.

Alprostadil↗
PubMed1997

Coexpression of multiple Sertoli cell and Leydig cell marker genes in the spontaneous testicular tumor of F344 rat: evidence for phenotypical bifurcation of the interstitial cell tumor.

The development of testicular tumor has been frequently observed in some laboratory rat strains. In the present study, we have further characterized the testicular tumor that spontaneously develops in the F344 rat (F344/Jcl). Tumor cells first appeared in the interstitium and developed into multifocal nodular lesions. In the later stage, the whole testes were occupied by tumor cells that consisted of three different types of cells in morphological appearance: large clear type, small eosinophilic type and intermediate type. To determine the character of these cells, we examined the expression of marker genes for Sertoli cells (e.g., transferrin) and Leydig cells (e.g., 3 beta-hydroxysteroid dehydrogenase 1 (3 beta-HSD 1)). Transferrin and 3 beta-HSD 1 mRNAs were found in all 8 tumor samples analyzed by northern blotting. By in situ hybridization, we observed a substantial amount of 3 beta-HSD 1 mRNA and little or no transferrin mRNA in the large clear cells. In contrast, the small eosinophilic cells showed little or no 3 beta-HSD 1 mRNA and a large amount of transferrin mRNA, suggesting that the tumor was a mixture of at least two types of cells. Other Sertoli cell marker genes, such as cyclic protein 2 and sulfated glycoprotein 2, were expressed in all 8 tumors analyzed, and testin and steel factor (SLF), the c-kit receptor ligand, were also expressed in some of the tumors (testin, 75%; SLF, 25%), while other Leydig cell markers, LH receptor and c-kit, were expressed in 87% and 80% of the tumors, respectively. These results indicate that the spontaneous testicular tumor of F344 rat is of interstitium origin, showing phenotypical bifurcation possibly via transdifferentiation.

3-Hydroxysteroid Dehydrogenases↗
PubMed1997

Quantitative analysis of interferon alpha/beta receptor mRNA in the liver of patients with chronic hepatitis C: correlation with serum hepatitis C virus-RNA levels and response to treatment with interferon.

We analysed the expression of interferon (IFN) alpha/beta receptor mRNA in the liver of patients with chronic hepatitis C and examined the relationship between the expression of this receptor gene and the level of hepatitis C virus (HCV)-RNA as well as the response to 16 weeks of 6 x 10(6) units IFN. The mean level of IFN alpha/beta receptor mRNA in patients with chronic HCV infection (expressed as delta cycle; 10.8 +/- 1.9 (mean +/- SD); n = 39) was significantly higher than that of control subjects (9.4 +/- 0.5; n = 6; P < 0.01). There was a significant negative correlation between the level of IFN alpha/beta receptor mRNA and serum HCV-RNA in 39 patients with chronic hepatitis C (R = -0.546; P < 0.01). The mean level of IFN alpha/beta receptor mRNA in six patients who showed a complete response to IFN therapy (12.3 +/- 1.6) was higher than that of 15 patients who failed to respond to therapy (10.1 +/- 1.5; P < 0.01). Our results are consistent with the suggestion that the anti-viral activity of IFN depends on the level of the IFN alpha/beta receptor on hepatocytes in patients with chronic hepatitis C.

Adult↗
PubMed1997

A case of lymphoid interstitial pneumonia in a 3-month-old boy not associated with HIV infection: immunohistochemistry of lung biopsy specimens and serum transforming growth factor-beta 1 assay.

The case of a 3-month-old boy with lymphoid interstitial pneumonia (LIP) is reported. He had cough and tachypnea, his weight gain was poor and a chest radiograph showed microgranular shadows in almost all lung areas. Histological investigations revealed severe cellular infiltration by a variety of lymphoid and plasma cells with lymphoid follicle formation in the alveolar walls and also around the bronchioles. Foamy macrophages, a few lymphocytes and exudate filled the alveolar spaces. Epithelial cells lining the air spaces expressed human leukocyte antigen (HLA)-DR. Lymphocytes and macrophages in the alveolar spaces expressed transforming growth factor (TGF)-beta strongly. Serum TGF-beta 1 concentrations were measured eight times during the course of his illness. They exceeded the upper end of the normal range in four samples and were within it in the others. These results suggested that dysfunction of the immune system, especially abnormal expression of HLA-DR in non-immune cells and exaggerated production of TGF-beta played important roles in the pathogenesis of LIP in this patient.

Antigens, CD↗
PubMed1997

A patient with acromegaly who showed remarkable improvement of hyperglycemia after treatment with octreotide.

A case with diabetes mellitus associated with growth hormone (GH)-producing pituitary adenoma is described. A 56-year-old woman who had been treated for diabetes mellitus for 3 years, was admitted for the treatment of hyperglycemia. She showed a few acromegalic features and her plasma GH level was 146 +/- 16 ng/ml. After improvement of plasma glucose level by insulin injection, octreotide therapy (100 micrograms/8 hours) was started. Seven days after the initiation of octreotide therapy, the fasting plasma glucose level was almost normalized without insulin injection. After the octreotide treatment, urinary C-peptide excretion was significantly decreased and the plasma GH level became within normal range. In this case, octreotide appears to have improved the insulin sensitivity by reducing the plasma GH level.

Acromegaly↗
PubMed1997

Bilateral adrenal lymphoma with neoplastic angioendotheliosis.

We report a case of bilateral lymphoma of the adrenal glands. A 61-year-old man was admitted to our hospital in clinical shock with anuria. Endocrine examination indicated a diagnosis of Addison's disease. Large tumors were found bilaterally in the suprarenal area, and a needle biopsy was performed, and the diagnosis was malignant lymphoma. Treatment with chemotherapy achieved a moderate response. He was discharged, but died 1 month later. On autopsy, microscopic examination showed extensive intravascular infiltration of lymphoma cells. We considered this to be a case of bilateral adrenal lymphoma with neoplastic angioendotheliosis.

Acute Kidney Injury↗
PubMed1997

[Diagnostic criteria for Non-ABCDE hepatitis].

Hepatitis viruses A, B, C, D and E are all well-characterized, molecularly defined agents with unequivocal disease association. Usual diagnosis for these virus infections are established by serological markers which are specific antigens or antibodies for these virus infections. But serological diagnosis occasionally shows pseudonegative results because this method is indirect diagnosis. In contrast, molecular diagnosis catches directly components of viral structure. Molecular diagnosis is also able to show the appearance and disappearance of these hepatitis viruses. Diagnostic criteria for Non-ABCDE hepatitis is the exclusion of hepatitis viruses A, B, C, D and E infections by using not only serological diagnosis but also molecular diagnosis.

Acute Disease↗
PubMed1997

[Abdominal aortic aneurysm and annuloaortic ectasia in siblings with Marfan syndrome].

A combination of annuloaortic ectasia (AAE) and abdominal aortic aneurysm (AAA) appeared in siblings with Marfan syndrome is presented. The patients were a 53-year-old female and her younger brother. The brother died of arrhythmia twenty years before while waiting for surgical repair of AAE. His AAA and Marfan syndrome were ascertained at autopsy. The female patient received surgical repair for AAA and AAE subsequently. Pathologic study of the resected aneurysm revealed cystic medial necrosis. A combination of AAE and AAA developed in two members of a family with Marfan syndrome is extremely rare.

Aortic Aneurysm, Abdominal↗
PubMed1997

[Ventricular septal perforation due to coronary artery spasm--a case report].

A 70-year-old female was referred due to chest pain and cardiogenic shock. Echocardiogram showed ventricular septal perforation (VSP) with large left to right shunt. ECG indicated ischemia on the left anterior descending region. Instantaneous coronary angiogram was done under the support of IABP. Neither obstructive nor stenotic lesions were found in the coronary arteries. Coronary artery spasm was a likely cause of VSP. The patient underwent emergency surgery within 12 hours from the onset. The VSP, 2 cm in diameter, was located on the postero-apical portion of the ventricular septum. The defect was closed by endocardial patch method using an equine pericardium. Postoperative course was uneventful, and the patient was transferred 3 weeks after the operation.

Aged↗