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Biomedical subjects

T Tomiyama

Publications and source records attributed to T Tomiyama.

At least 109 records · Page 6Linked to original sources
PubMed1992

Acute effect of an alpha 1-adrenoceptor antagonist on urinary sodium excretion, plasma atrial natriuretic peptide, arginine vasopressin, and the renin-aldosterone system in healthy subjects.

To elucidate the mechanism underlying the sodium retention caused by alpha 1-adrenoceptor blockade in man, a placebo-controlled, randomised, double-blind study has been made of the acute effects of bunazosin an alpha 1-antagonist, on urinary sodium excretion, atrial natriuretic peptide (ANP), arginine vasopressin (AVP), and the renin-aldosterone system in 7 healthy men. A single oral dose of bunazosin 2.0 mg caused a significant reduction (P less than 0.05) in urinary sodium excretion after 0-2 h, 2-4 h, and 4-6 h. The mean values for plasma ANP, AVP, aldosterone, and cortisol concentrations at those times were similar after placebo and bunazosin, and plasma renin activity was significantly increased 2 and 4 h after bunazosin. Pretreatment with oral enalapril 10 mg, an angiotensin converting enzyme inhibitor, did not prevent the bunazosin-induced reduction in urinary sodium excretion. There was a significant positive correlation between the drug-induced changes in blood pressure and urinary sodium excretion. The results suggest that ANP, AVP, and renin-aldosterone may play little role in the sodium retention caused by acute alpha 1-adrenoceptor blockade in man.

Adrenergic alpha-Antagonists↗
PubMed1992

Prostaglandin E1 enhances hepatic portal venous flow by dilating the portal vascular bed in 70% hepatectomized dog.

The effects of portal, hepatic arterial and femoral venous administration of prostaglandin E1 (PGE) on portal venous flow (PVF) and hepatic arterial flow HAF were examined before and after 70% hepatectomy in anesthetized dogs. In the hepatectomized condition, portal venous administration of PGE (0.5 microgram/kg/min) caused an increase in PVF without any change in systemic arterial pressure (SAP). HAF was unchanged following the injection. The portal effect of PGE on PVF was dose-dependent, and a reduction in portal venous resistance was seen. However, the same dose of PGE failed to change PVF under intact liver conditions. Hepatic arterial administration of PGE (0.5 microgram/kg/min) brought no significant change in PVF or HAF, with or without hepatectomy. Femoral venous administration of PGE (0.5 micrograms/kg/min) produced an increase in PVF concomitant with a significant decrease in SAP. HAF showed no change after the injection. A decrease in PVR was seen only in the hepatectomized condition. It is concluded that PGE is potent in increasing PVF in the hepatectomized condition, and the portal vasculature is involved as the site of action.

Alprostadil↗
PubMed1992

The preclinical safety evaluation of human monoclonal antibody against cytomegalovirus.

The human monoclonal antibody against cytomegalovirus (Mab C23) was examined pharmacokinetically and toxicologically as part of the preclinical studies prior to approval for human use. Rats given repeated intravenous administrations of Mab C23 produced no antibodies against Mab C23 and maintained a blood Mab C23 level in a dose-dependent manner. However, pregnant rabbits produced antibodies against Mab C23. The half-life of Mab C23 in plasma was 15.9 days in rats, which was similar to that of normal human serum gamma-globulin (NHSG). Neither behavioral effects nor circulatory disturbance was found in mice, rats, and dogs even after a single intravenous injection of 100 or 200 mg/kg, which corresponds to 50 or 100 times the intended clinical dosage. The repeated doses of 2, 10, or 20 mg/kg of Mab C23 on six occasions with 1- or 2-week intervals elicited a transient decrease in leukocyte counts in rats given 10 or 20 mg/kg, but no adverse effects in cynomolgus monkeys. Mab C23 did not cause any reproductive or developmental toxicity when administered to rats and rabbits at dose levels of 20 mg/kg or less. However, pregnant animals showed lower plasma levels of Mab C23 than non-pregnant animals. The chromosomal aberration test disclosed no clastogenicity in human lymphocytes. An immunostaining for Mab C23 revealed no localizations in several tissues of cynomolgus monkeys given intravenous doses of Mab C23.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

In vivo measurement of spatial dose distribution with thermoluminescent sheet around high dose-rate intracavitary source: application to rectal cancer.

For intracavitary high dose-rate radiation therapy, a thermoluminescent [TL] sheet for in vivo measurement of spatial dose distribution around source has been recently developed. The TL sheet was found to have a linear response with a very wide dynamic range from at least 0.002 cGy to 5000 cGy for 60Co gamma-rays. This TL sheet (40 cm x 50 cm x 200 microns), which is composed of Teflon mixed with BaSO4:Eu doped powder, is very flexible and can be cut to the desired size. In addition, this sheet is easy to handle because of its insensitivity to room light. The spatial dose distribution is displayed in a color mode by using a newly developed TL sheet readout system. For a clinical application, the TL sheet was wrapped on an applicator for intracavitary radiation therapy of a rectal cancer and was inserted into the rectum. The location of the TL sheet could be confirmed with diagnostic X ray film. After irradiation with high dose-rate 60Co source, the in vivo relative dose distribution on the surface of the rectum was determined. This TL sheet provided a convenient means of measuring the relative dose distributions around 60Co sources of various patterns in intracavitary radiation therapy.

Brachytherapy↗
PubMed1992

Generation and characterization of a human monoclonal antibody that neutralizes diverse HIV-1 isolates in vitro.

OBJECTIVE: The purpose of this study was to develop and characterize human monoclonal antibodies (HuMAb) that neutralize HIV-1. DESIGN: Based upon previous studies involving the generation of HuMAb that neutralize other enveloped viruses, we thought it feasible to generate HuMAb that might neutralize HIV-1. METHODS: A HuMAb was generated by fusing splenic B-cells from an HIV-positive patient with a mouse myeloma cell line. Flow cytometry was used to determine surface reactivity of the HuMAb on HIV-infected and non-infected cells. Radioimmunoprecipitation was employed to elucidate the antigen recognized by the HuMAb. A cell survival assay was used to determine the ability of the HuMAb to neutralize divergent isolates of HIV-1 in the presence or absence of complement. A gp120-CD4 inhibition enzyme-linked immunosorbent assay (ELISA) was developed in order to initiate studies to determine the mechanism of neutralization by the HuMAb. RESULTS: An anti-HIV HuMAb was generated that neutralized two HIV-1 isolates (IIIB and MN) without complement and which neutralized one divergent isolate (RF) and one clinical isolate in the presence of complement. This HuMAb, designated S1-1, was found, by flow cytometric analysis, to react with the surface of HIV-1-infected but not with uninfected cells. Radioimmunoprecipitation analysis demonstrated that S1-1 binds to native HIV gp120, but not dithiothreitol (DTT)-treated gp120. In addition, HuMAb S1-1 did not bind to denatured HIV antigens in Western blot analysis. HuMAb S1-1 effectively inhibited the binding of gp120 to soluble CD4 in ELISA. CONCLUSIONS: These results suggest that the epitope recognized by S1-1 is conformational and conserved among diverse HIV-1 isolates and may represent an uncharacterized HIV neutralizing domain within or close to the CD4 binding domain on gp120. HuMAb S1-1 might have a role to play in vaccine development or passive immunotherapy.

Antibodies, Monoclonal↗
PubMed1991

Recognition of human immunodeficiency virus glycoproteins by natural anti-carbohydrate antibodies in human serum.

Anti-carbohydrate antibodies were isolated from Human immunodeficiency virus (HIV) negative human serum by affinity chromatography using yeast mannan followed by protein A. The purified mannan-binding IgG (MBIgG) bound to HIV glycoproteins gp 160, gp 120 and gp 41 in Western blot. Immunofluorescence revealed that MBIgG bound to HIV/IIIB-infected H9 cells but not to uninfected H9 cells, suggesting that carbohydrate structures recognized by MBIgG are specifically expressed on HIV-infected cells. MBIgG did not neutralize infectivity of HIV. These results show that normal human serum contains natural antibodies reactive to carbohydrate structures of HIV glycoproteins propagated in human cells.

Antibodies↗
PubMed1991

Response of newly established mouse myeloid leukemic cell lines to MC3T3-G2/PA6 preadipocytes and hematopoietic factors.

Some mouse myeloid leukemias induced by X-irradiation and serially transplanted into syngenic mice do not proliferate in vitro even in the presence of hematopoietic factors. To examine whether such leukemic cells can proliferate in response to stromal cells, we cocultured them with MC3T3-G2/PA6 (PA6) preadipocytes, cells that can support the growth of hematopoietic stem cells. All leukemias developed into in vitro cell lines, showing a dependence on contact with the PA6 cells. Two cell lines responded to none of the known hematopoietic factors including interleukin-3 (IL-3), IL-4, IL-5, IL-6, GM-CSF, G-CSF, M-CSF, and Epo. These results demonstrate that the mechanism of the action of PA6 cells is different from that of any of the known hematopoietic factors, and that, because these two leukemic cell lines retained the ability to grow in vivo, responsiveness to the known hematopoietic factors is not essential for the leukemic cell growth in vivo. Furthermore, all leukemic cell lines could respond also to the preadipocytes fixed with formalin, paraformaldehyde, or glutaraldehyde, suggesting that some molecule(s) associated with the surface of PA6 cells or with extracellular matrix secreted by the preadipocytes is responsible for the leukemic cell growth.

Adipose Tissue↗
PubMed1991

Diagnosis of biliary diseases via a naso-biliary catheter.

Nasobiliary double contrast radiography and nasobiliary cytological diagnosis via nasobiliary catheter were performed in 30 patients with biliary diseases to assess the diagnostic usefulness and limitations of the procedures. The results showed that the contour and fine mucosal pattern of the extrahepatic bile duct could be demonstrated adequately (88%) by nasobiliary double contrast radiography. In contrast, the intrahepatic bile duct could not be fully demonstrated (56%) by nasobiliary double contrast radiography because of its anatomical structure. On the other hand the fine reticular pattern of the mucosa was defined in each section of the gallbladder by nasobiliary double contrast radiography. This procedure is thus a valuable method for detection of mucosal lesions of the extrahepatic bile duct and gallbladder, especially carcinoma. The cell collection rate was not as high (59%) using conventional nasobiliary cytological diagnosis. Brush cytology via a nasobiliary catheter was shown to be a useful adjunct to other diagnostic procedures.

Barium Sulfate↗
PubMed1991

A human monoclonal antibody against varicella-zoster virus glycoprotein III.

Hybridomas producing human monoclonal antibodies (HMAbs) against varicella-zoster virus (VZV) were generated by fusing murine myeloma cells with human lymphocytes immunized in vitro. An assay system was developed to select anti-glycoprotein (gp)III HMAbs from the pool of anti-VZV HMAbs. A murine anti-gpIII MAb, 4B7, did not react with a VZV-infected cell homogenate, but did react with a VZV-infected cell monolayer, whereas anti-gpI and anti-gpII MAbs reacted with both antigens. Hybridomas were screened to obtain HMAbs having a reaction profile similar to that of 4B7 and one such clone, V3, stably produces human IgG1 (kappa). HMAb V3 immunoprecipitated a VZV antigen of 115K to 120K, which was not immunoabsorbed by an anti-gpII HMAb, implying that V3 recognizes gpIII. V3 neutralized VZV independently of complement, unlike anti-gpI and anti-gpII HMAbs. All five strains of VZV tested were completely neutralized by V3, and the dose of V3 required to reduce the number of virus plaques by 50% ranged from 0.027 to 0.15 micrograms/ml. V3 was also able to inhibit the spread of virus infection from infected to uninfected cells, whereas anti-gpI and anti-gpII HMAbs could not. In addition, V3 mediated antibody-dependent cellular cytotoxicity but not complement-dependent cytotoxicity of VZV-infected cells. The results suggest that an anti-gpIII HMAb may provide a new means of passive immunoprophylaxis and also help to identify an antigenic epitope appropriate for a subunit vaccine.

Animals↗
PubMed1991

[Clinical evaluation of cefuzonam (CZON) for bacterial pneumonia and lung abscess: comparative study with cefotiam (CTM)].

A double blind study was conducted to objectively evaluate the usefulness of Cefuzonam (CZON) in the treatment of bacterial pneumonia and lung abscess. Cefotiam (CTM) was used as a control drug. Each drug was administered by intravenous drip infusion at 1 g at a time, twice daily, for 14 days as a rule. The results are as follows: 1. Enrolled in this study were 145 cases in total, comprising 72 of CZON group and 73 of CTM group. Of the total cases, 109 (53 of CZON group and 56 CTM group) were evaluated for clinical efficacy by the evaluation committee. Exclusion rate and background of patients were not significantly different between the two groups. 2. Clinical effectiveness assessed by the committee showed the efficacy rates of 84.9% (45 cases out of 53) for the CZON group and 83.3% (47 cases out of 56) for the CTM group, with no significant difference between the two groups. 3. The bacteriological eradication rates were 89.5% (17 strains out of 19) for the CZON group and 78.3% (18 strains out of 23) for the CTM group, with no significant difference between the two groups. 4. The incidence of side effects was 5 cases (7.5%) for the CZON group and 3 cases (4.2%) for the CTM group. The incidence rate of laboratory test abnormality was 28.4% (19 cases out of 67) for the CZON group and 31.3% (12 cases out of 67) for the CTM group. There was no significant difference between the two groups. 5. Usefulness rates calculated by the committee were 79.2% (42 cases out of 53) for the CZON group and 76.8% (43 cases out of 56) for the CTM group. There was no significant difference between the two groups. These results show that CZON is a useful drug in the treatment of bacterial pneumonia and lung abscess.

Adolescent↗
PubMed1991

Hyperinsulinemia and blood pressure in non-obese middle-aged subjects with normal glucose tolerance.

A possible link between hyperinsulinemia and blood pressure was studied in non-obese subjects with normal glucose tolerance. First, the responses in plasma glucose and serum insulin to an oral glucose load (75-g oral glucose tolerance test) were compared between 42 patients with essential hypertension and 93 normotensive control subjects. Second, of the 93 normotensive subjects, the relations of serum insulin levels to blood pressure, serum cholesterol, and triglycerides concentrations were assessed in 8 hyperinsulinemic (serum insulin level [during fasting, or after glucose loading, or both] greater than 2 S.D. higher than the mean) and 8 pair-matched normoinsulinemic subjects (serum insulin level within 1 S.D. of the mean), individually matched for age, sex, and body mass index. Plasma glucose and serum insulin responses to the glucose load in hypertensive subjects were identical to the respective responses in normotensive subjects, while the mean total serum cholesterol level was slightly higher (p less than 0.05) in hypertensive subjects. The respective values for systolic and diastolic blood pressures, and total serum cholesterol and triglycerides concentrations were comparable in hyperinsulinemic and normoinsulinemic subjects. These results did not suggest a close association between hyperinsulinemia and elevated blood pressure in non-obese middle-aged Japanese subjects with normal glucose tolerance.

Blood Glucose↗
PubMed1990

Preparation of human monoclonal antibodies against a cytomegalovirus glycoprotein complex of 130 and 55 kDa.

Nine human monoclonal antibodies (MAbs) with neutralization activity against cytomegalovirus (CMV) were obtained by screening human MAbs using a CMV glycoprotein complex of 130 and 55 kDa (gp130/55). The gp130/55 antigen was purified by immunoaffinity chromatography and the purified antigen used to detect anti-gp130/55 MAbs in an enzyme-linked immunosorbent assay. Relatively few of the human anti-CMV MAbs were directed against gp130/55 but all showed high neutralization activities to a variety of clinical isolates with titers (ED50 values) ranging from 0.15 to 7.9 micrograms/ml. Six of the nine anti-gp130/55 MAbs required complement for virus neutralization. Such human MAbs may prove to be useful for passive immunotherapy against CMV infection.

Antibodies, Monoclonal↗
PubMed1990

Comparison of the renal effects of dilevalol and carteolol in patients with mild to moderate essential hypertension.

The effects of 6 weeks of treatment with dilevalol 100 mg once daily, or carteolol 10 mg once daily, on renal blood flow (RBF), glomerular filtration rate (GFR) and total renal vascular resistance (TRR) were studied in 10 patients with mild-to-moderate essential hypertension in a randomised cross-over experiment. Both drugs lowered the systolic and diastolic blood pressures to a similar extent without altering the heart rate. Carteolol non-significantly decreased RBF by 9.2% and GFR by 12.3% without altering. TRR, whereas dilevalol produced a significant reduction in TRR by 13.2% (p less than 0.05), a non-significant decrease in RBF by 4.6% and no change in GFR. Neither drug changed plasma osmotic pressure, serum total protein concentration, electrolytes or plasma aldosterone concentration. Plasma renin activity tended to be lower in the dilevalol phase as compared to the carteolol phase. The results suggest that dilevalol may cause a greater decrease in TRR and less reduction in GFR when compared to carteolol in patients with mild-to-moderate essential hypertension. The difference in the renal effects might be due to the difference in the potency of vasodilatory properties of both drugs at the doses applied.

Adult↗
PubMed1990

Renal effects of nicardipine, a calcium antagonist, in hypertensive type 2 (non-insulin-dependent) diabetic patients with and without nephropathy.

The renal effects of oral maintenance doses of nicardipine 60-120 mg/day have been studied in 18 hypertensive patients with Type 2 (non-insulin-dependent) diabetes mellitus: 6 with normoalbuminuria (urinary albumin excretion rate, AER less than 20 micrograms.min-1, Group A); 6 with incipient nephropathy, (AER 20-200 micrograms.min-1, Group B); and 6 with overt nephropathy (AER greater than 200 micrograms.min-1, Group C). Treatment for 4 weeks significantly lowered the systolic and diastolic blood pressures and reduced total renal vascular resistance in all three groups. Nicardipine increased renal blood flow significantly in Group C and slightly in Group B, and had no effect in Group A. Glomerular filtration rate remained unchanged in all three groups. It significantly reduced AER and the fractional clearance of albumin in Group B, whereas AER in Groups A and C was not altered. Plasma renin activity, aldosterone concentration, osmotic pressure, serum total protein and albumin concentrations and haemoglobin A1c level were similar in the control and nicardipine phases in all three groups. The results suggest that nicardipine may preserve renal function whilst having a concomitant hypotensive action in hypertensive Type 2 diabetic patients with normoalbuminuria and incipient nephropathy, and that the drug may improve renal blood flow in patients with overt nephropathy. The effect of the drug on urinary albumin excretion may deserve further investigation.

Albuminuria↗