Biomedical subjects

H Tamura

Publications and source records attributed to H Tamura.

At least 19 recordsLinked to original sources

PubMed1992

A new sensitive microplate assay of plasma endotoxin.

We have developed a microplate method for determining endotoxin in platelet-rich plasma-using Endospecy, an endotoxin-specific chromogenic Limulus test reagent. Nonspecific activators and inhibitors of the test were eliminated by exposing samples (5 microliters) to the alkali reagent consisting of KOH, CaCl2, Triton X-100, ethyleniminepolymer and N,N-bis(2-hydroxyethyl)glycine. The recoveries of various endotoxins were almost complete and not enhanced by dilution. The dose-response curve was linear over endotoxin concentrations of 2-400 pg/ml with good precision (C.V. less than 5.0%). Normal human plasmas (n = 30) contained less than 5.0 pg/ml of endotoxin in reference to that of Escherichia coli 0111: B4. All plasma samples with high concentration of endotoxin by a conventional method showed high values by the microplate assay as well. Since it does not require centrifugation, the new treatment allows the whole reactions to proceed on the same microplate. This permits us to apply the Limulus test to an automated assay system, making plasma endotoxin determination simpler and more rapid than a conventional test tube method.

Detergents↗

PubMed1992

G test, a new direct method for diagnosis of Candida infection: comparison with assays for beta-glucan and mannan antigen in a rabbit model of systemic candidiasis.

An indirect method to measure beta-glucan, a major structural component of yeast cell walls, is available, but has the disadvantage of requiring the combined use of two assays. Recent reports describe the fungal index, which measures the difference between the conventional limulus test, in which factors C and G react with endotoxin and beta-glucan, and a new endotoxin-specific test, in which only factor C reacts with endotoxin. The G test was developed as a direct method to measure beta-glucan, and contains only factor G reacting with beta-glucan alone. In this study, the G test was examined in sera of rabbits with experimental systemic candidiasis, and compared with the fungal index and mannan assay. The G test showed positive in all rabbits with systemic candidiasis faster and with higher titers than with the fungal index. Three rabbits with fulminant systemic candidiasis showed higher levels of reactivity with the G test and the fungal index than two rabbits with mild reactions. Mannan was positive by at least one serum in four of five rabbits by the latex agglutination test, and there was a good correlation between these assays. The G test is a good serodiagnostic method for the detection of candidiasis.

Animals↗

PubMed1992

Determination of plasma (1-->3)-beta-D-glucan: a new diagnostic aid to deep mycosis.

We present additional evidence that plasma from patients with deep-seated mycoses contains (1-->3)-beta-D-glucan. Digestion of such samples with endo-(1-->3)-beta-D-glucanase completely abolished the ability of the plasma to activate factor-G, a horseshoe crab coagulation enzyme that is extremely sensitive to this polysaccharide. Measurement of plasma (1-->3)-beta-D-glucan is a promising method for the diagnosis of deep-seated mycoses and for monitoring the response of these infections to antifungal therapy.

Amino Acid Sequence↗

PubMed1992

Molecular cloning of a rat liver cDNA encoding the 16 kDa subunit of vacuolar H(+)-ATPases: organellar and tissue distribution of 16 kDa proteolipids.

A cDNA (T3-L) encoding the 16 kDa subunit of vacuolar H(+)-ATPase was cloned from a cDNA library of rat liver. A polypeptide of 155 amino acids with a molecular mass of 15,807 Da (pI = 9.5) having four hydrophobic stretches was predicted. T3-L polypeptide was 92% and 100% identical with the 16 kDa proteolipid of bovine chromaffin granule and that of mouse, respectively. Antisera raised against the NH2-terminal of the T3-L polypeptide reacted positively with the membrane ghosts of rat liver tritosomes and the partially purified H(+)-ATPase thereof. Western blotting of subcellular fractions with the antisera showed high abundance of 16 kDa protein in the lysosomes, although a significant amount was also detected in the Golgi apparatus. Western blotting of rat tissues revealed high levels of 16 kDa proteolipid in the brain and the kidney. Northern blots with T3-L similarly showed considerably high expression of T3-L mRNA in the brain and the kidney. Southern hybridization of rat genomic DNA with T3-L showed at most three distinct bands, regardless of the stringency of hybridization and whether hybridization was performed with its subfragments. This suggests the possibility of multiple (at least three) homologous/identical genes encoding 16 kDa proteolipid. The possible presence and significance of isoforms of 16 kDa proteolipid in rats are discussed.

Amino Acid Sequence↗

PubMed1992

Mass production of sphingomyelinase of Bacillus cereus by a protein-hyperproducing strain, Bacillus brevis 47, and its purification.

Sphingomyelinase (sphingomyelin cholinephosphohydrolase) [EC 3.1.4.12] of Bacillus cereus was overproduced in a protein-hyperproducing strain, B. brevis 47, by cloning the gene into an expression vector pNU211, which has been developed to express a foreign gene utilizing a promoter and a signal sequence of an outer cell wall protein gene. From 1 liter of culture, about 10 mg of protein was purified to near-homogeneity by two steps of column chromatography; this is almost 500 times higher production compared to the conventional preparation from the original strain, B. cereus IAM 1208. The N-terminal amino acid sequence of the secreted enzyme was identical to that of the authentic enzyme, indicating that the signal sequence for secretion of B. cereus was processed properly in B. brevis 47.

Amino Acid Sequence↗

PubMed1992

Molecular analysis of immunoglobulin heavy chain genes coding for idiotypic and anti-idiotypic antibodies involved in B-B cellular interaction.

We recently reported that a unique B cell clone (B19-1d), specific for a cross-reactive idiotype (CRI) on MOPC104E myeloma protein (M104E), enhances Igh-restricted CRI+ antibody production. In this paper, we report the nucleotide sequences of immunoglobulin heavy chain variable regions (VH) of both M104E and B19-1d-derived hybridoma (HB19) antibodies. The sequence data revealed that both belong to the J558 germ line VH gene subfamily. Strikingly, not only the VH region, but also the leader sequences of M104E and HB19 are very similar to each other at 88% (VH) and 91% (leader) homology, but they use different D and J segments. The VH region sequence similarity is highest among the germ line VH gene sequences of the BALB/c J558 subfamily so far screened. Southern hybridization data, using 5'-noncoding regions of either M104E or HB19 genomic VH gene clones as probes, revealed that both VH genes are conserved in the M104E CRI producer strains of mice. Moreover, these probes show the restriction length polymorphism pattern of mouse VH genes in various strains. That the HB19 VH gene locates to the 5' upper arm of the M104E VH gene on the chromosome was suggested by Southern blot hybridization. Immunoglobulin VH gene restriction of idiotypic and antiidiotypic B-B cellular interaction is discussed from a molecular point of view.

Amino Acid Sequence↗

PubMed1992

T-independent polyclonal activation of B cells in vitro by immunoglobulin binding substance (IBS) from the granary weevil.

Experiments are described for T-independent polyclonal activation of B cells in vitro by the immunoglobulin binding substance (IBS) from the granary weevil. The affinity-chromatographically purified IBS was used. IBS is a heat-, alkali- and acid-stable glucopeptide which is characterized by non-specific immunoglobulin binding to the Fab fragment. The purified IBS consists of three polymer homologues whose molecular weights are 12-14,000, 25-30,000 and more than 150,000 Da. IBS did not stimulate DNA synthesis by murine T cells, macrophages or plasma cells whereas it did stimulate that by mature B cells without any help from T cells or macrophages. IBS also stimulated both in vitro IgG production by spleen cells and in vitro sensitization of spleen cells by sheep red cells (SRBC). IBS was found to stimulate DNA synthesis by B cells mediated by binding to surface immunoglobulins of B cells. IBS is thought to be a useful amplifier for inducing human hybridomas and a valuable tool for examining mature B cells, both diagnostically and experimentally.

Animals↗

PubMed1992

Activity-dependent potentiation and depression of visual cortical responses to optic nerve stimulation in kittens.

1. To see whether long-lasting changes in synaptic efficacy are induced in the developing visual cortex (VC), field potentials evoked by test stimulation given alternatively to each of the optic nerves (ONs) were recorded from VC of kittens ranging in age from 4 to 8 wk. In some experiments, field potentials were recorded simultaneously from the dorsal lateral geniculate nucleus (LGN) in addition to VC. 2. Tetanic stimulation was applied to one of the ONs for 1-60 min at 5 Hz. Homosynaptic potentiation of cortical responses, defined as an increase lasting > 2.5 h in the cortical field potential evoked by test stimulation of the ON that was tetanized, was induced without any changes in LGN responses in 3 of the 12 kittens tested. Heterosynaptic depression, defined as a decrease lasting > 0.5 h in the field potential evoked by stimulation of the ON that was not tetanized, was also induced in two of those three kittens. 3. To elucidate a role of inputs originating from spontaneous activity of retinal ganglion cells in induction of potentiation and depression in the cortex, tetrodotoxin (TTX) was injected into both eyes of 11 kittens. After we confirmed the suppression of retinal activity by TTX, tetanic stimulation was applied to ON. Homosynaptic potentiation of cortical responses was induced in 6 of the 11 kittens, and the ratio of the mean amplitude of posttetanic responses to that of pretetanic responses for the 11 kittens was on average larger than that for the 12 control kittens. Heterosynaptic depression was not observed in any of the 11 kittens. 4. To see a role of postsynaptic activity in induction of potentiation and depression, gamma-aminobutyric acid (GABA) was applied continuously to the VC by an infusion pump in 10 kittens. Tetanic stimulation was given to ON while cortical activities were suppressed by GABA. After recovery of cortical activities, homosynaptic depression was found to be induced in 3 of the 10 kittens, but homosynaptic potentiation was not observed at all. The ratio of amplitude of posttetanic to pretetanic responses at the tetanized side for the 10 kittens was on average smaller than that for the 11 TTX-injected kittens. 5. These results can be accounted for by the modified covariance model in which the relation of postsynaptic activity and direction of changes in synaptic efficacy is formulated.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1992

Digoxin-like immunoreactive substance in urine of patients with mucocutaneous lymph node syndrome (MCLS).

Levels of digoxin-like immunoreactive substance (DLIS) and dehydroepiandrosterone sulfate (DHEA) in urine from patients with mucocutaneous lymph node syndrome (MCLS) were measured by radioimmunoassay. Because DLIS of stored samples was often below the level of detection by conventional immunoassay, the authors used 80% ammonium sulfate and extraction with phosphate buffer and then 80% hot ethanol. To study the origin of raised levels of DLIS in urine, the synthesis of DLIS by cultured human umbilical vein endothelial cells (HUVEC) was tested in vitro. The correlation between DLIS and DHEA levels was not significant. Mean levels of urinary DLIS corrected for creatinine in the patients with MCLS were significantly higher than in both normal and diseased controls. The culture medium of HUVEC was found to contain DLIS activity. These results show that MCLS should be added to the clinical states associated with an increased urinary concentration of DLIS and that the endothelial cells are one source of DLIS in man.

Blood Proteins↗

PubMed1992

Enhancing effect of butorphanol on medetomidine-induced sedation in pigs.

Enhancing effect of an opiate agonist-antagonist butorphanol (0.2 mg/kg) on sedation induced by medetomidine (80 micrograms/kg) was evaluated in pigs. Butorphanol significantly enhanced the depth of medetomidine-induced sedation and prolonged the duration of that assessed by posture score and spontaneous movement of pigs. The combination of medetomidine and butorphanol produced excellent muscle relaxation and moderate surface analgesia which was enough for procedures with mild pain in pigs.

Animals↗

PubMed1992

Antagonism of medetomidine sedation by atipamezole in pigs.

The efficacy of atipamezole as a medetomidine antagonist was evaluated in pigs. The atipamezole doses (intramuscularly) were 80, 160, 320 and 480 micrograms/kg of body weight, which were one, two, four and six times higher than the preceding medetomidine dose (80 micrograms/kg, intramuscularly). Atipamezole effectively reversed medetomidine-induced sedation, and the optimal action was seen at doses of 160 and 320 micrograms/kg. Recovery from sedation was quick and smooth, and adverse effects such as hyperactivity or tachycardia were minimal with either dose.

Adrenergic alpha-Agonists↗

PubMed1992

A balanced anesthesia with a combination of xylazine, ketamine and butorphanol and its antagonism by yohimbine in pigs.

The effects of intramuscular injections of xylazine (2 mg/kg)-ketamine (15 mg/kg) [X-K15], and xylazine (2 mg/kg)-ketamine (5 mg/kg)-butorphanol (0.22 mg/kg) [X-K5-B] were compared in atropinized (0.05 mg/kg) miniature pigs (pigs). Both combinations induced the anesthesia for more than 1 hr, however X-K5-B induced the more potent and well balanced anesthesia as compared with X-K15, although the amount of ketamine was reduced to one third. The duration of loss of pedal reflex, an indicator of surgical anesthesia, in X-K5-B (62 +/- 13 min) was significantly (P less than 0.05) longer than in X-K15 (28 +/- 19 min). In addition, X-K5-B was accompanied by loss of laryngeal reflex in all pigs. Recovery from anesthesia in X-K5-B was much smoother than in X-K15, and the administration of yohimbine (0.05 mg/kg) could rapidly and smoothly reverse the anesthesia induced by X-K5-B, although it was accompanied by a transient fall in blood pressure and tachycardia. The combination of xylazine, ketamine and butorphanol appears to be a relatively safe and widely available anesthesia for the period of one hour in pigs.

Acid-Base Equilibrium↗

PubMed1992

Sedative effects of medetomidine in pigs.

Sedative effects of medetomidine, a potent selective and specific alpha 2-adrenoceptor agonist, were evaluated in pigs using 5 different doses (30, 50, 80, 100 and 150 micrograms/kg of body weight) and compared with those of xylazine (2 mg/kg). Atropine (25 micrograms/kg) was mixed with both drugs to prevent severe bradycardia. All drugs were administered intramuscularly. Medetomidine at a dosage of 30 micrograms/kg produced more potent sedation than xylazine. The depth of sedation induced by medetomidine was dose dependent within the range from 30 to 80 micrograms/kg. At 100 or 150 micrograms/kg, the depth of sedation was mostly the similar level to that at 80 micrograms/kg but the duration was prolonged. The degree of muscle relaxation produced by medetomidine also seemed to be dose dependent from 30 to 80 micrograms/kg and was stronger than that produced by xylazine. An increase in the duration of muscle relaxation was dose dependent up to 150 micrograms/kg. No analgesic effect was produced by xylazine, however moderate analgesia was obtained by medetomidine. There were no marked changes in heart rate and respiratory rate during the observation period in pigs of any groups, however mild hypothermia after the administration of both drugs was observed. From these results, medetomidine has a significant and dose-dependent sedative effects which are much more potent than that of xylazine, and a combination of 80 micrograms/kg of medetomidine and 25 micrograms/kg of atropine is suitable for sedation with lateral recumbency and moderate muscle relaxation without notable side effects in pigs.

Analgesia↗

PubMed1992

A case of congenital dyserythropoietic anemia type II associated with hemochromatosis.

A 54-year-old woman with anemia, diabetes mellitus and liver dysfunction was admitted to our hospital. Numerous binucleated erythroblasts in the bone marrow, a positive serum acidified test, and the presence of anti I and anti i antigens on the surface of her erythrocytes indicated that she had congenital dyserythropoietic anemia (CDA) Type II. Hemochromatosis was confirmed by a liver biopsy. This case is a sibling of a patient with CDA Type II reported by Omine et al in 1981 (Acta Haematol Jpn 44:1). They report that no physical or hematological abnormalities were found when she was examined at the age of 29 years. Twenty-five years later, she developed CDA Type II and hemochromatosis. This case indicates that long-term observation of the family members of a patient with CDA Type II is necessary.

Anemia, Dyserythropoietic, Congenital↗

PubMed1992

Alterations of anionic charge and/or sites of the glomerular basement membrane in the heterologous phase of passive Heymann nephritis.

Alterations of the anionic charge and/or sites of the glomerular basement membrane (GBM) in the heterologous phase of passive Heymann nephritis (PHN) were studied. Rats with PHN induced by a single injection of anti-Fx1A IgG were examined at days 1, 2, 3 and 4. The left kidney was perfused with ruthenium red (RR) solution as a cationic probe. The RR particles (= anionic sites) in the GBM were counted and expressed as the number of RR particles per unit length of GBM. For quantitative determination of the total anionic charge of the GBM, the GBM-bound ruthenium (= anionic charge) was measured with an atomic absorption spectrophotometer (AAS). Abnormal proteinuria corresponding to a decrease in anionic charge was detected at days 3 and 4. The anionic sites in the lamina rara externa (LRE) adjacent to immune complex (IC) deposits were found to have diminished earlier from day 1 onwards. This diminution was largely confined to areas adjacent to the IC deposits and was significantly correlated with the amount of urinary albumin excretion. Proteinuria in the heterologous phase of PHN would thus appear to be causally related to a decrease in the number of anionic sites in the LRE adjacent to IC deposits.

Animals↗

PubMed1992

[A case of primary amyloidosis associated with giant cell infiltration within a Bowman's capsule].

A 67-year-old man was hospitalized with a diagnosis of nephrotic syndrome. Physical findings at admission were generalized edema and macroglossia. Urinalysis showed massive proteinuria, + +occult blood, and granular and broad casts. Ig A lambda monoclonal gammopathy was noted in the serum. There was no evidence of myeloma in the bone marrow aspirate, scintigram or X-ray of the bone. A biopsy specimen of the kidney showed massive deposits of structureless material in the glomeruli. Marked cell infiltration was also observed in the interstitium. Multinucleated giant cells were occasionally seen in the Bowman's capsules and the interstitium. There were reactive changes in the Bowman's capsule adjacent to the giant cell. The deposits were proved to be amyloid by positive staining with Congo red and apple-green birefringence by polarized light. In addition, microfibrills seen on electron microscopy displayed deposits. Amyloid depositions were observed in other tissues such as gingiva, skin and tongue. Staining of amyloid with Congo red was resistant to potassium permanganate, and amyloid was positively stained with lambda-light chain of immunoglobulin. These findings indicated that the patient had primary amyloidosis. Infiltration of the multinucleated giant cell has been reported only in patients with familial amyloidosis and secondary amyloidosis associated with rheumatoid arthritis. To our knowledge the present case is a first report of the giant cell infiltration in a Bowman's capsule in primary amyloidosis.

Aged↗

PubMed1992

[Clinical experience with the omnicarbon valve prosthesis].

Between January 1985 and March 1990, isolated valve replacements with the Omnicarbon valve were performed in 90 patients aged 34-72 years. There were 53 aortic valve replacements (AVR) and 37 mitral valve replacements (MVR). The cumulative follow-up was 320 patient-year (py) with a mean follow-up of 3.7 +/- 1.4 years. There were 3 operative and hospital mortalities (3.3%), resulting from retrograde aortic dissection during cardiopulmonary bypass, postoperative renal failure, and rupture of infective pseudoaneurysm in ascending aorta. Seven patients died during the late postoperative period, 4 due to valve-related causes. Two of these patients died of prosthetic valve endocarditis (PVE), while the others died of thromboembolism (including valve thrombosis). The overall actuarial survival rate at 6 years was 86.3% (98.8% for AVR, and 82.1% for MVR). There were 2 thromboembolic events (one mesenteric artery thrombosis, and the other valve thrombosis). The linearized incidence of thromboembolism was 0.63%/py. PVE occurred in 3 patients (0.94%/py). One patient (0.31%/py) was found to have a valve dehiscence due to aortitis syndrome. There were no instances of anticoagulant-related hemorrhage, or valve-related hemolysis. The actuarial rate of freedom from valve-related mortality at 6 years was 93.5% (100% for AVR, and 88.1% for MVR). On the basis of a follow-up period of 6 years, good clinical results and a low incidence of valve-related complications can be demonstrated with Omnicarbon valve.

Adult↗

PubMed1992

[Percutaneous transluminal coronary angioplasty in patients with previous coronary artery bypass grafting].

Percutaneous transluminal coronary angioplasty (PTCA) has been used to treat patients with previous coronary artery bypass grafting (CABG). Seven patients with previous CABG underwent coronary artery or vein graft angioplasty following a recurrence of symptoms. Fifteen lesions were attempted in 7 patients. The primary angiographic success rate was 100%. The primary angiographic success rate was defined as reduction of a stenosis by at least 20% of the vessel diameter, leaving a stenosis of less than 60%. There were no complications following PTCA such as death or myocardial infarction. No patients were referred for urgent surgery. Three patients have undergone another PTCA after 3 months and remain well. All patients at follow-up continue to have improved symptoms. Our experience suggests that the patients with recurrence of coronary artery or bypass stenosis following CABG may be suitable for PTCA.

Aged↗