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Biomedical subjects

T Ishihara

Publications and source records attributed to T Ishihara.

At least 343 records · Page 19Linked to original sources
PubMed1994

[Measurement of serum free thyroxine concentrations using anti-T4 monoclonal antibody].

A new one-step radiolabeled antibody radioassay for measuring free T4 (FT4) in serum (Amerlex-MAB FT4) was evaluated in comparison with an analog tracer RIA of FT4 (Amerlex-M FT4). In this new method, 125I-labeled anti-T4 monoclonal antibody which has cross-reactivity with T3 is used as a tracer. When incubated with serum sample, the tracer binds to FT4 and the remaining tracer binds to a T3 coated particle (Amerlex MAB). The radioactivity bound to Amerlex MAB is measured. Counts of 125I bound to the T3 coated particle were inversely proportional to sample FT4 concentrations. The assay procedure is as follows. Fifty microliter of patient's serum or standard FT4, 500 microliters of Amerlex MAB and tracer is incubated at 37 degrees C for 30 minutes and centrifuged. Then the radioactivity of Amerlex MAB is measured using an autowell gamma counter. The intra-and interassay coefficients of variation were 1.6-2.7% and 2.6-8.0%, respectively. Although Amerlex-M FT4 values were significantly increased by adding human albumin to the serum, Amerlex-MAB FT4 values were not effected by the change of albumin concentrations. In nonthyroidal illness patients, Amerlex-MAB FT4 values were not affected by the concentrations of albumin, TBG and NEFA. The euthyroid central 95% reference range for FT4 determined by Amerlex-MAB FT4 was 0.99 to 1.54 ng/dl. The FT4 levels correlated well with the metabolic status. Although Amerlex-M FT4 values were spuriously increased in patients with anti-T4 autoantibodies, Amerlex-MAB FT4 values were not affected by the autoantibodies. Amerlex-MAB FT4 values of normal pregnant women were slightly lower in the second and third trimesters than in the first trimester. These lower FT4 concentrations in late pregnancy were considered likely not to be artefact by low serum albumin or high serum TBG but to be a physiological event. Amerlex-MAB FT4 values correlated well with FT4 indices and inversely correlated with TSH levels. A significant correlation (n = 401, r = 0.86, p = 0.0001) was observed between Amerlex-MAB FT4 and Amerlex-M FT4 values in various thyroid conditions without antithyroid autoantibodies. In summary, this new assay for FT4 is simple, rapid and reproducible. The measurement is useful for the evaluation of physiological thyroid function and helpful in the management of patients with thyroid diseases.

Adult↗
PubMed1993

Morphological evaluation of amyloid-laden arteries in leptomeninges, cortices and subcortices in cerebral amyloid angiopathy with subcortical hemorrhage.

To investigate the relationship between cerebral amyloid angiopathy and subcortical (lobar) hemorrhage, we examined the severity of amyloid deposition in the leptomeningeal, cortical and subcortical arteries in 28 autopsied elderly patients with cerebral amyloid angiopathy with subcortical hemorrhage, deep cerebral hemorrhage or without hemorrhage. The severity was evaluated in terms of the frequency of amyloid-laden arteries and the degree of amyloid deposition within the arteries. The frequency of amyloid-laden arteries, especially among arteries over 200 microns in diameter, was higher in subcortical hemorrhage group than in the deep hemorrhage group and the non-hemorrhage group, and when the degree of amyloid deposition in the arteries was divided into four grades (none, mild, moderate or severe), the severity was higher in the subcortical hemorrhage group than in the deep cerebral hemorrhage group and the non-hemorrhage group. These results suggest that severe cerebral amyloid angiopathy is related to non-traumatic subcortical hemorrhage in elderly persons.

Aged↗
PubMed1993

Localized amyloidosis in squamous cell carcinoma of uterine cervix: electron microscopic features of nodular and star-like amyloid deposits.

An ultrastructural study of amyloid deposits in four cases of squamous cell carcinoma of uterine cervix was performed. The amyloid deposits reacted with anti-keratin antiserum on frozen sections. Amyloid deposits showed nodular (4 cases) and star-like forms (3 cases). Nodular amyloid deposits were composed of slightly whorled fibrils, measuring 7-10 nm in width. Some of them contained cellular debris and thicker, more electron-dense filaments than amyloid fibrils. In three cases, filamentous tumour cells and filamentous masses were observed together with amyloid. Star-like amyloid deposits were composed of bundles of straight amyloid fibrils. Some of the tumour cells in contact with star-like amyloid deposits had deep cytoplasmic invaginations, where closely packed amyloid fibrils were arrayed in parallel fashion. In addition, a few tumour cells had membrane-bound amyloid fibrils in the cytoplasm. It is suggested that nodular amyloid deposits are derived from the tumour cells through filamentous degeneration. Amyloid fibrils in star-like amyloid deposits are thought to be formed within the cytoplasm or in the vicinity of invaginated cytoplasmic membranes of the tumour cells.

Aged↗
PubMed1993

Muscle damage progression in Duchenne muscular dystrophy evaluated by a new quantitative computed tomography method.

The progression of muscle damage was studied in the lower extremity and trunk muscles of patients with Duchenne muscular dystrophy (DMD) with a new quantitative computed tomography (CT) method. The degree of muscle fiber loss and fat tissue replacement was quantified using the indices of percent cross-sectional area (%CSA) of muscle and fat, or the percentages of the area having the CT numbers of normal muscle and fat. A cross-sectional study in 71 patients showed that as the disability stage progressed, both CT number and %CSA of muscle decreased while %CSA of fat increased. The rate of progression was different for each muscle, and the order of involvement was clarified. The CT findings were also significantly correlated with muscle strength, indicating validity of our method. Our findings of the natural course of muscle involvement would be useful in providing appropriate rehabilitative care as well as assessing the efficacy of therapeutic interventions.

Adolescent↗
PubMed1993

Castleman disease. Unusual retroperitoneal location indistinguishable from malignant tumor in preoperative angiographic appearance.

Castleman disease (angiofollicular lymph node hyperplasia) has been reported rarely as a solitary retroperitoneal mass radiographically indistinguishable from retroperitoneal malignancies. We report a case of a hyaline-vascular variant of Castleman disease presenting as a pararenal mass. The computerized tomographic and angiographic appearances of this lesion are presented, and the clinical importance of the differential diagnosis of retroperitoneal tumors is discussed.

Adult↗
PubMed1993

Molecular cloning and tissue distribution of a receptor for pituitary adenylate cyclase-activating polypeptide.

Pituitary adenylate cyclase-activating polypeptide (PA-CAP) is a polypeptide hormone related to vasoactive intestinal polypeptide (VIP). Rat PACAP receptor cDNA was isolated from a brain cDNA library by cross-hybridization with rat VIP receptor cDNA. The recombinant PACAP receptor expressed in COS cells bound PACAP with about 1000 times higher affinity than VIP, and PACAP stimulated adenylate cyclase through the cloned PACAP receptor. The rat PACAP receptor consists of 495 amino acids, contains seven transmembrane segments, and has a significant similarity with other Gs-coupled receptors, such as VIP, glucagon, and secretin receptors. PACAP receptor mRNA was abundantly expressed in the brain, but not in the peripheral tissues except for the adrenal gland. In situ hybridization revealed a high level of expression of PACAP receptor mRNA in the hippocampal dentate gyrus, olfactory bulb, and cerebellar cortex.

Amino Acid Sequence↗
PubMed1993

Localization of a gene for Fukuyama type congenital muscular dystrophy to chromosome 9q31-33.

Fukuyama type congenital muscular dystrophy (FCMD) is an autosomal recessive severe muscular dystrophy associated with an anomaly of the brain. Twenty-one FCMD families, 13 of them with consanguineous marriages, were analysed by genetic linkage analyses with polymorphic microsatellite markers to map the FCMD gene. Significant lod scores were obtained with the markers D9S58 (Zmax = 5.81 at theta = 0.06), D9S59 (Zmax = 4.33 at theta = 0.02), and HXB (Zmax = 3.28 at theta = 0.09) on chromosome 9q31-33. Multipoint analysis placed FCMD between D9S58 and D9S59, with a maximum lod score of 16.93. These markers will be useful for presymptomatic, prenatal and carrier diagnosis of family members carrying FCMD, and they represent important resources for the identification of a gene responsible for FCMD.

Chromosome Mapping↗
PubMed1993

Effects of spiraprilat, an angiotensin-converting enzyme inhibitor, on anesthetized dogs in a new model of acute left ventricular failure.

Spiraprilat, a new angiotensin-converting enzyme (ACE) inhibitor, was compared with enalaprilat for its ability to improve left ventricular (LV) function and metabolism in anesthetized open-chest dogs with a new model of acute LV failure (ALVF) induced by embolization of the left coronary artery with 50 microns plastic microspheres followed by intravenous (i.v.) infusion of methoxamine. With this procedure, LV end-diastolic pressure (LVEDP) increased from 4.2 +/- 0.7 to 12.8 +/- 1.3 mm Hg and remained at approximately 12 mm Hg throughout the experiment. Cardiac output (CO) decreased from 1.25 +/- 0.12 to 0.79 +/- 0.06 and 0.55 +/- 0.02 L/min at 30 and 90 min after methoxamine infusion, respectively. LVdP/dtmax and dP/dt/P decreased, while total peripheral resistance (TPR) increased. These hemodynamic changes indicated establishment of stable ALVF of a moderate degree. Moreover, decreases in myocardial lactate consumption and contents of creatine phosphate in the myocardium indicated the existence of moderate ischemia. The new ACE inhibitor, spiraprilat, as well as enalaprilat (30 micrograms/kg i.v.) effectively decreased mean aortic pressure (30%), LVEDP (20%), and TPR (30%) and increased stroke volume (SV) CO, and dP/dt/P. Both agents decreased myocardial oxygen consumption (20%) and caused a significant increase in myocardial creatine phosphate contents. These data indicate that the beneficial effects of both inhibitors extended not only to LV function but also to myocardial energy metabolism in ALVF.

Adenosine Triphosphate↗
PubMed1993

Sclerosing lipogranuloma of the male genitalia: analysis of the lipid constituents and histological study.

An analysis of lipids and histological examination were performed on tissues resected from 2 patients with sclerosing lipogranuloma of the scrotum. The clinical course and histological characteristics were consistent with those reported previously for typical primary sclerosing lipogranuloma of the male genitalia. There was no history of the injection or topical application of oils or fats. Both of our patients had eosinophilia and the lesions showed eosinophilic infiltration. Complete natural regression occurred several months after partial resection of the lesion in both cases, and no recurrence has been noted during follow-up. This lipid analysis and histological study revealed that no exogenous fatty elements were present and suggested that degeneration of endogenous fat due to some allergic mechanism might be involved in the development of sclerosing lipogranuloma. The eosinophilia associated with this disease and its spontaneous regression after partial resection also support this assumption.

Adult↗
PubMed1993

Antiarrhythmic agents act differently on the activation phase of the ACh-response in guinea-pig atrial myocytes.

1. Anti-acetylcholine effects of pilsicainide, flecainide, disopyramide and propafenone on the acetylcholine (ACh)-induced K+ current (IK.ACh) were examined in dissociated guinea-pig atrial myocytes under whole-cell voltage clamp by the use of the 'concentration-clamp' technique. 2. The IK.ACh was activated with a latency of about 100 ms after 1 microM ACh application and desensitized to a steady-state level. The latent period and the time to peak response were shortened with increasing ACh concentration. 3. The values of half-maximal inhibition (IC50) on the peak and steady state responses were 25 and 25 microM for pilsicainide, 1.7 and 2.0 microM for disopyramide, 19 and 2.0 microM for flecainide and 0.7 and 0.2 microM for propafenone, respectively. 4. Pilsicainide and disopyramide increased the latent period and the time to peak of IK.ACh in a concentration-dependent manner. Flecainide and propafenone did not change the latent period, but shortened the time to peak and hastened the decay of IK.ACh in a voltage-independent manner. 5. The results suggest that the mechanisms underlying the anti-acetylcholine effect of antiarrhythmic drugs are different among these drugs: i.e., pilsicainide and disopyramide mainly block the muscarinic ACh receptors while flecainide and propafenone inhibit the K+ channel itself as open channel blockers.

Acetylcholine↗
PubMed1993

Continuous hematocrit monitoring method in an extracorporeal circulation system and its application for automatic control of blood volume during artificial kidney treatment.

A two-frequency electrical conductivity method for measuring hematocrit has been developed for use in the continuous monitoring of circulating blood volume during artificial kidney treatment. Using this method, an algorithm for programmed control of blood volume also has been developed. This hematocrit measurement method is based on the beta-dispersion of blood conductivity, and the values measured during hemodialysis are in good agreement with the laboratory hematocrit values obtained by a Coulter counter. Programmed control of blood volume was used 29 times on 11 patients undergoing long-term dialysis. In each case, the blood volume was maintained within 2.5% of the desired level, and stable control was achieved even with disturbances caused by eating, change in body position, and so on. These methods can be used to study the relationship between blood volume and dialysis-induced hypotension during artificial kidney treatment and to achieve adequate ultrafiltration without clinical adverse effects.

Blood Volume↗
PubMed1993

Epithelial myoepithelial tumour of the tracheal gland.

A case of epithelial myoepithelial tumour originating from the tracheal gland in a 57 year old woman is described. The tumour was removed by segmental tracheal resection and end-to-end anastomosis. Histologically, the tumour comprised clear cells and presented a monophasic pattern. Immunohistochemical analysis showed that the tumour cells were positive for both S-100 protein and smooth muscle actin. suggesting that this tumour resembles a subtype of epithelial-myoepithelial carcinoma described in the 1990 WHO international classification of salivary glands. Although some reports describe a clear cell dominant epithelial myoepithelial carcinoma, in this case local invasiveness or regional lymphnode metastasis was not proved through investigation. It is therefore concluded that this was an epithelial myoepithelial tumour rather than a carcinoma.

Female↗