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Biomedical subjects

H Kitamura

Publications and source records attributed to H Kitamura.

At least 361 records · Page 20Linked to original sources
PubMed1992

Ultrastructural and immunohistochemical similarities between glomerular arteriolar and mesangial lesions in experimental diabetes.

It has thus far been speculated that plasma proteins have leaked and accumulated in diabetic expanded mesangium. We have previously shown that glomerular arteriolar hyalinosis has frequently occurred and has consisted of basement membrane-like extracellular matrix in alloxan diabetic rats. In the present study, the two diabetic glomerular lesions, arteriolar hyaline nodules and increased mesangial matrix, were comparatively evaluated by means of electron microscopy and immunohistochemistry. It was revealed that both of these lesions contained, in common, finely particulate extracellular matrix mingled with cytoplasmic fragments, and exhibited intense immunoreactions for IgG and IgM. It is indicated that both types of diabetic glomerular lesions are essentially of the same nature.

Animals↗
PubMed1992

Similarity of the constituents between glomerular arteriolar and mesangial lesions in experimental diabetes.

In our previous studies in experimental diabetic rats, we have observed close similarities of ultrastructure and accumulation of IgG and IgM between the mesangial expansion and arteriolar hyalinosis of the glomerulus, and have presumed that both diabetic lesions are essentially of similar nature. In the present study, we carried out a further study on the constituents of both these lesions, using the PA-TCH-SP-PD technique for neutral carbohydrates, sialic acid and glycoproteins and the IgG-gold-silver technique for type IV collagen and fibronectin. The above staining and immunolabelings proved to be comparable in both lesions of diabetic glomerulopathies. This argues for the hypothesis of the identity of the two lesions.

Animals↗
PubMed1992

Suppression of sympathetic nervous system activity by nicorandil during exercise.

1. Treadmill testing was done and plasma epinephrine and norepinephrine were measured during exercise and recovery in 21 patients with coronary artery disease given nicorandil. 2. Epinephrine levels during exercise did not change significantly with nicorandil, but the percent change in epinephrine with nicorandil tended to be lower during exercise. 3. Norepinephrine levels after exercise were suppressed with nicorandil (with, 424 +/- 15 pg/ml; without, 760 +/- 16, P less than 0.05). 4. Also, the percent change in norepinephrine with nicorandil was significantly decreased during exercise and recovery (with, 259 +/- 11%; without, 555 +/- 19, P less than 0.01). 5. Therefore, nicorandil suppressed the sympathetic nervous system hyper-response to exercise.

Adult↗
PubMed1992

Modulation of the incidence of hamster pulmonary endocrine cell hyperplasia by unilateral collapse of the lung.

We evaluated the effects of the unilateral collapse of the left lung on the formation of pulmonary endocrine cell hyperplasia (PECH) induced by 4-nitroquinoline 1-oxide (4NQO) in Syrian golden hamsters. Ten hamsters were injected subcutaneously with 20 mg/kg body weight of 4NQO, once a week for 4 weeks and treated with injection of silicone rubber into the left thorax at the 8th experimental week. Another 30 animals were divided into three groups: treated with 4NQO only, left lung collapse only, and vehicle only. All animals were sacrificed at the 30th week. The lung tissues were embedded in paraffin; 50 serial sections were made from the tissues of each animal and were studied histologically and immunohistochemically. PECH showed a positive immunostain for calcitonin and/or serotonin. In the uncollapsed right lungs of the animals treated with both 4NQO and unilateral collapse, the mean incidence of PECH was 12.2 x 10(-2)/mm3 lung volume; the incidences of PECH in the animals treated with 4NQO only, collapse only, and vehicle only were 4.1, 3.8, and 1.4 x 10(-2)/mm3, respectively. In the collapsed left lungs, PECH did not form, regardless of 4NQO treatment. This study demonstrates that unilateral collapse of the lung modulates the incidence of PECH induced by 4NQO in hamsters.

4-Nitroquinoline-1-oxide↗
PubMed1992

Effect of alacepril on blood pressure and neurohumoral factors at rest and during dynamic exercise in patients with essential hypertension.

We assessed blood pressure and neurohumoral factors at rest and during exercise in 10 patients with essential hypertension before and after treatment with the new angiotensin converting enzyme inhibitor, alacepril (25-50 mg day-1). Alacepril significantly lowered mean blood pressure at rest and at the same exercise load as before treatment without affecting heart rate response. The response of plasma renin activity, plasma aldosterone, and plasma adrenaline were not changed by alacepril, but increase of plasma angiotensin II and plasma noradrenaline during exercise were significantly attenuated after alacepril treatment (ANOVA, P = 0.04, both). The change in mean blood pressure during exercise was positively correlated with the decrease in plasma angiotensin II (r = 0.65, P < 0.05). These results demonstrated that alacepril was effective in essential hypertension both at rest and during exercise, suggesting that the antihypertensive effect during exercise might be related to the decrease in pressor hormones, especially in plasma angiotensin II.

Adult↗
PubMed1992

Activation of complement in normal serum by hydrogen peroxide and hydrogen peroxide-related oxygen radicals produced by activated neutrophils.

Neutrophils activated by soluble particulate stimuli generate superoxide anion and subsequently form hydrogen peroxide and other oxygen radicals. The effect of hydrogen peroxide on the complement system in normal serum was investigated. Treatment of normal serum with hydrogen peroxide resulted in a diminution of the haemolytic activity of the total and alternative complement pathways and the haemolytic titres of C3 and C5 but not of C2, in normal serum. These decreases in complement activity depended on the concentration of hydrogen peroxide added to the serum. Immunoelectrophoretic analysis of hydrogen peroxide-treated serum showed that C3 and C5 proteins were activated. Complement degradation products C3a and C5a were produced in normal serum treated with hydrogen peroxide, and 20 mM EDTA abolished C3a and C5a production in hydrogen peroxide-treated serum but 20 mM Mg-EGTA did not. Catalase completely abolished and dimethylsulphoxide and D-mannitol, hydroxyl radical scavengers, partially inhibited the hydrogen peroxide-mediated complement activation. Hypochlorite, incubated with normal serum, significantly inhibited serum haemolytic activity, and sodium thiosulphate, a reducing agent, abolished the effect of hypochlorite. Normal serum incubated with activated neutrophils showed neutrophil chemotactic activity and decreased serum haemolytic activity, and the addition of catalase or methionine (5 mM) completely abolished the effects of activated neutrophils. These results suggest that hydrogen peroxide activates complement via an alternative pathway of complement activation and that hydroxyl radicals and other hydrogen peroxide-related species such as hypochlorite are most likely involved in hydrogen peroxide-mediated complement activation. Complement activation by oxygen radicals produced by activated neutrophils may be one of the mechanisms by which complement is activated in human immune complex diseases.

Complement Activation↗
PubMed1992

Bulimia nervosa in a pair of male monozygotic twins.

This is a report of a pair of male monozygotic twins meeting the DSM-III-R criteria for bulimia nervosa. At the age of 15, both brothers began to diet and suffered from bulimia. They were admitted to psychiatric hospitals and separated. After admission, their clinical course dramatically changed. The differences in their clinical courses and endocrinological data are suggestive as to the roles of environmental and hereditary factors in the etiology of bulimia nervosa.

Adolescent↗
PubMed1992

Plasma catecholamine responses to dynamic exercise in patients with coronary artery disease--the relationship between sympathetic activity and systolic blood pressure and exercise-induced ventricular arrhythmias.

In order to investigate the relationship between sympathetic activity and postexercise systolic blood pressure (SBP) and exercise-induced ventricular arrhythmias in patients with coronary artery disease (CAD), we studied 38 patients and 9 normal subjects who underwent treadmill testing. Peak pressure-rate product was similar in the 2 groups. The plasma concentrations of norepinephrine and epinephrine at rest and immediately after exercise were significantly higher in patients with CAD compared with normal subjects (norepinephrine at rest, p < 0.01; norepinephrine immediately after exercise, p < 0.05; epinephrine at rest, p < 0.05; epinephrine immediately after exercise, p < 0.05). The level of norepinephrine immediately after exercise was significantly higher in 15 patients with a postexercise SBP increase than in 23 patients without that SBP change (p < 0.05), whereas the level of epinephrine was similar in the 2 groups. The level of epinephrine immediately after exercise was significantly higher in 10 patients with exercise-induced premature ventricular contractions than in 28 patients without those arrhythmias (p < 0.05), whereas the level of norepinephrine was similar in the 2 groups. We conclude that a postexercise SBP increase is related to the augmentation of sympathoneural activity and that exercise-induced ventricular arrhythmias are related to the augmentation of sympathoadrenal activity.

Arrhythmias, Cardiac↗
PubMed1992

Three-dimensional architecture of pericytes with special reference to their topographical relationship to microvascular beds.

Microvascular beds and pericytes in the submandibular gland, thyroid gland and heart were studied by combined scanning electron microscopy and chemical digestion. The submandibular gland had a relatively loose network of blood capillaries, the thyroid gland possessed a close-meshed network of capillaries, and those in the myocardium ran parallel to the long axis of myocardial cells. The thyroid gland exhibited the largest numbers of pericytes. Three types of pericytes could be distinguished by their shape and localization. Type I pericytes, which were confined to true capillaries, had a fusiform or polygonal cell body, a few long, slender longitudinal processes (primary ones) and short, fine circumferential processes (secondary ones). Type II pericytes, which were found in the arterial side of myocardial capillaries, were characterized by large, circumferential band-like processes completely encircling the vessel. Type III pericytes, which were seen on the venous side of thyroid and myocardial capillaries, had a flattened cell body and short, irregular processes. Type II and III pericytes appear to show an intermediate or transitional form between smooth muscle cells and typical pericytes (Type I). Judging from the configuration of pericytes suggests that these are related to functions such as contraction as well as mechanical support.

Animals↗
PubMed1992

Cardiovascular and sympathetic nervous responses to mental stress in hyperthyroid patients.

We measured the cardiovascular and sympathetic nervous responses to mental stress in subjects with hyperthyroidism. Ten hyperthyroid subjects and 10 age- and sex-matched normal subjects performed mental arithmetic. At rest, the heart rate was higher in hyperthyroid subjects than in normal subjects, but systolic blood pressure, plasma norepinephrine, and epinephrine concentrations did not differ between the two groups. Systolic blood pressure and heart rate during stress, and the changes in blood pressure and in plasma epinephrine concentration from rest to stress, were higher in hyperthyroid subjects than in normal subjects. Therefore, cardiovascular and adrenal responses to mental stress were abnormally high in subjects with hyperthyroidism.

Adolescent↗
PubMed1992

Cardiovascular and sympathetic nervous response to dynamic exercise in patients with essential hypertension.

To investigate the relationship among systolic blood pressure (SBP) during exercise (EX), left ventricular hypertrophy (LVH) and plasma norepinephrine concentration (NE) in patients with essential hypertension (HT), 20 patients with HT and 20 age- and sex-matched normal subjects were studied using treadmill testing. According to the change in SBP from rest to EX (delta SBP), patients with HT were classified into two groups (group I, n = 12, delta SBP less than 72 mmHg: group II, n = 8, delta SBP greater than or equal to 72 mmHg). There were no significant differences between the two groups with regard to SBP at rest, NE at rest and NE on EX. However, SBP at peak EX, delta SBP and the incidence of LVH were greater in group II than in group I. We conclude that exaggerated SBP response to EX in patients with HT is related to LVH.

Adult↗
PubMed1992

Parathyroid hormone-related protein as a cause of hypercalcemia in a B-cell type malignant lymphoma.

Hypercalcemia occurred in a patient with non-Hodgkin's (B-cell type) lymphoma when generalized lymphadenopathy developed. Despite low normal plasma parathyroid hormone (PTH), nephrogenous cAMP (NcAMP) was not suppressed, and serum and urine PTH-related protein (PTH-rP) levels were elevated. The plasma level of 1,25(OH)2D was within normal range. The combined chemotherapies successfully reduced the tumor size, serum Ca, PTH-rP, and lactic dehydrogenase. Serum osteocalcin was suppressed while the patient was hypercalcemic, and increased after chemotherapy. In the extract of the tumor tissue obtained post mortem, bioactivity stimulating the production of cAMP in osteoblasts was demonstrated along with the immunoreactive PTH-rP. This is the first report of a B-cell lymphoma producing PTH-rP and its association with humoral hypercalcemia of malignancy.

Aclarubicin↗
PubMed1992

[Cardiac and plasma catecholamine response to dynamic exercise in hyperthyroidism].

To investigate cardiac and sympathoadrenal responses to dynamic exercise, heart rate, systolic blood pressure, serial plasma norepinephrine (NE) and epinephrine (E) concentrations during multistage treadmill exercise were measured in 24 hyperthyroid patients (mean age; 42 +/- 16) and 24 age-sex matched control subjects. Eleven patients were re-examined in the euthyroid state after antithyroid therapy. Exercise duration was shorter in patient with hyperthyroidism. Also, the heart rates and systolic blood pressures at rest and in the early stage of exercise were significantly higher in hyperthyroidism. NE at rest (normal vs hyperthyroid: 124 +/- 10 vs 80 +/- 7 pg/ml, p < 0.01) and NE at peak exercise (475 +/- 38 vs 310 +/- 38 pg/ml, p < 0.01) were lower in hyperthyroidism. E at rest (22 +/- 2 vs 29 +/- 4 pg/ml, n.s.) did not differ, however, E during the first stage of exercise (30 +/- 3 vs 69 +/- 12 pg/ml, p < 0.01) was higher in hyperthyroidism. Re-examination for the euthyroid state revealed the decreases in the heart rates and systolic blood pressures at rest and in the early stage of exercise, and the normalization of the NE and E response. Thus, patients with hyperthyroidism was in the hyperdynamic cardiac state at rest and during dynamic exercise, which was accounted for by decreased sympathetic nervous activity and increased adrenomedullary responses. These modifications of sympathoadrenal response seemed reversible when patients were controlled by antithyroid therapy.

Adolescent↗
PubMed1992

[Expression of epidermal growth factor receptor in adult human airway epithelium--application of AMeX method].

To elucidate the role of epidermal growth factor (EGF) in the maintenance and repair of airway epithelial cells in adult humans, we investigated immunohistochemically whether EGF receptor (EGFR) is expressed in these cells. In the present study, we employed the AMeX method (Sato et al., 1986) for tissue preparation. We first examined the expression of EGFR in peripheral lung tissue and bronchial tissue obtained at surgery from thirteen adult patients with lung carcinoma. The results showed that there was no positive staining for EGFR in the bronchial surface epithelium, bronchial glandular cells, bronchiolar epithelium or alveolar lining cells. There was also no expression of EGFR in cells comprising areas of basal cell hyperplasia and epidermoid metaplasia in the bronchus, or alveolar cell hyperplasia and columnar cell metaplasia in fibrotic lung tissue. Second, we examined the expression of EGFR in regenerating distal airway epithelial cells, which were experimentally produced by xenotransplantation of human lung tissue into the subcutaneous tissue of nude mice. There was also no expression of EGFR at any stage of regeneration from one week through six weeks after the transplantation. It is concluded that EGFR is not expressed, at least at an immunohistochemically detectable level, by airway epithelial cells of adult humans, not only in the quiescent state but also under conditions in which epithelial cells are stimulated to replicate. Thus, it appears unlikely that the EGF/EGFR system plays an important role in either maintenance or repair of airway epithelial cells in adult humans.

Adult↗
PubMed1992

[A case of squamous cell carcinoma of the lung associated with acanthosis nigricans and solitary bronchial papilloma].

A 58-year-old man diagnosed as having acanthosis nigricans symmetrically distributed on the face, neck, hands, navel and external genitals, was admitted to our department for further investigation of abnormal chest films. Bronchoscopy revealed squamous cell carcinoma of left S6 and solitary bronchial papilloma of left S3. After left pneumonectomy, facial hyperpigmentation improved slightly. About half of the reported cases of acanthosis nigricans are accompanied by various kinds of malignant neoplasms, mostly adenocarcinomas of the digestive system. The association with squamous cell carcinoma of the lung in our case appears to be unique. Only 16 cases of solitary bronchial papilloma, including our case which had the smallest diameter of 2 mm, have been reported in Japan. While it is suggested that malignant neoplasms contribute to abnormal epidermal growth such as acanthosis nigricans, a causal relationship between squamous cell carcinoma of the lung and bronchial papilloma cannot be established.

Acanthosis Nigricans↗
PubMed1992

[A method for determination of proinsulin levels in serum using both insolubilized anti-insulin antibody and anti-C-peptide antibody].

A method is described for determination of proinsulin levels in serum. The principle of the assay is that proinsulin reacts with both anti-insulin and anti-C-peptide antibodies. The assay procedure is as follows; Anti-insulin antibody fixed to bacterial cell wall and insolubilized is incubated with test serum to form a complex of proinsulin-anti-insulin antibody (solid phase), followed by washing twice with buffer to eliminate free C-peptide. Then, glycin-HCl buffer is added to dissociate the bound proinsulin. After centrifugation, the supernatant is neutralized with NaOH and proinsulin in it is measured using RIA kit for CPR assay. The assay is simple, sensitive and reproducible. Neither insulin nor C-peptide contained in test serum influences the proinsulin levels determined by this assay. The mean +/- S.D. of the fasting serum proinsulin levels of healthy donors was 7.0 +/- 2.6 PM/l. A patient with insulinoma showed extremely high serum proinsulin level, which decreased to the normal range after extirpation of insulinoma.

Antibodies↗
PubMed1992

Segmental mediolytic arteritis. Clinicopathologic study and three-dimensional analysis.

We describe the first recorded case of segmental mediolytic arteritis (SMA) in Japan. A 71-year-old Japanese woman developed sudden abdominal pain and went into shock during hospitalization for treatment of valvular heart disease. Laparotomy revealed a ruptured pseudoaneurysm of the left gastric artery. Histological examination of the resected artery revealed multiple extensive areas of the dilated wall where the media had partially or totally disappeared with or without the intima. These features were typical of those described previously for SMA (1,2). Three-dimensional analysis of the arterial lesions revealed that the residual media formed branches and cavities down the long axis of the artery, indicating that the major cause of the medial disappearance was arterial dissection. Three months later, the patient died of sepsis. Autopsy revealed pseudoaneurysm formation at three different locations in the splenic artery. Histologically, these pseudoaneurysms showed destructive changes in the arterial wall similar to those described above, with organization and thrombosis, and were considered to be the end-stage lesion of SMA. This case is considered to be the fifth adult case of SMA in the literature and the first one showing chronic changes.

Aged↗