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Biomedical subjects

N Tamura

Publications and source records attributed to N Tamura.

At least 163 records · Page 9Linked to original sources
PubMed1996

[Pulmonary eosinophilic granuloma with relatively rapid progression and remission].

A 53-year-old woman with a smoking history of 20 pack-years was admitted to the hospital because of dry coughing and exertional dyspnea that had progressed over the previous 3 months. A chest X-ray film taken one month before the onset of symptoms was almost normal. Diffuse small nodular shadows with infiltration were evident one month after the onset of symptoms, and increased rapidly until admission to the hospital. Eosinophilic granuloma was diagnosed histologically after thoracoscopy. The symptoms, chest X-ray findings and pulmonary-function data improved spontaneously after admission to the hospital and the nodular shadows had a almost completely disappeared by 5 months later; the patient continued to smoke. The present case is unique and valuable because it shows the natural course of eosinophilic granuloma from the onset of symptoms to remission.

Eosinophilic Granuloma↗
PubMed1996

[Idiopathic segmental anhidrosis].

We described two cases of idiopathic segmental anhidrosis. Case 1 was a 47-year-old man, who noticed anhidrosis on the right side of face and chest during body heating. Case 2 was a 54-year-old woman, who complained of anhidrosis on the left side of face and upper chest during exercise. Both cases had neither somatic neurological deficit nor autonomic failure except for anhidrosis pupil size and deep tendon reflexes were normal. Reflex sweating to pilocarpine was exaggerated in the anhidrotic areas in both cases, suggesting lesions in the preganglionic sudomotor nerves. Abnormal laboratory finding was elevated serum rheumatoid factor level in only case 2. Segmental anhidrosis was static for 1.5 year and one year, respectively. The previous literature contains similar four cases. Idiopathic segmental anhidrosis may be an abortive form of Ross' syndrome (tonic pupil, hyporeflexia and segmental anhidrosis).

Female↗
PubMed1996

[A case of sympathotonic orthostatic hypotension following herpes simplex encephalitis].

The etiology of sympathotonic orthostatic hypotension (SOH) is still unknown. We reported a 50-year-old male case of SOH associated with herpes simplex encephalitis. Eight days before admission to our hospital, he noticed fever, which was followed by intractable hiccup. He was admitted to a local hospital, where nuchal rigidity and mononuclear CSF pleocytosis were noted. On the 9th hospital day, he suddenly developed respiratory arrest, and his consciousness state deteriorated to coma. He was transferred to our hospital with artificial ventilation on the same day. The second CSF examination revealed pleocytosis and positive herpes-simplex-virus antibody. CAT scan showed diffuse high density areas in the bilateral temporal lobes. Intensive anti-herpetic therapy was started. On the 14th hospital day, spontaneous respiration came back and consciousness state was improved from coma to stupor. He gradually recovered to alert state and became ambulatory by the 30th hospital day. Seven weeks after the onset of his illness, he noticed orthostatic dizziness for the first time during his rehabilitation exercises. Blood pressure was 116/78mmHg at supine position and 82/62mmHg at standing position, and the heart rate was 83bpm, and 141bpm, respectively. Plasma noradrenaline concentration was 0.09 ng/ml (within normal range) at supine position, but increased to 0.29ng/ml upon standing. Catecholamine infusion tests revealed hyposensitivity in beta 2-receptors; decrease in blood pressure in response to isoprenaline was blunted, while increase of blood pressure to noradrenaline was not impaired. Nerve conduction studies and sweating tests were normal. When he was discharged from our hospital on the 87th hospital day, he still had orthostatic symptoms. His complete recovery took full one year. Some authors claimed that SOH is an abortive form of acute autonomic neuropathy, while others postulated that it was due to unbalanced cardiovascular alpha- and beta-adrenoceptor functions. SOH of the present case seems to be caused by the central nervous lesions; especially, the brain stem involvement due to herpes simplex encephalitis may well be causing SOH.

Autonomic Nervous System↗
PubMed1996

Deterioration of urinary findings after tonsil stimulation in patients with IgA nephropathy.

We studied whether urinary findings are affected by stimulation of tonsils in patients with IgA nephropathy. In 62 patients with IgA nephropathy and 20 patients with other renal diseases tonsils were stimulated by an ultra short wave for 10 min. Changes in amount of urinary protein, urinary sediment, blood leucocyte count, concentrations of serum IgA and serum secretory IgA were evaluated after tonsil stimulation. Forty of 62 patients with IgA nephropathy (65%) showed deterioration of urinary findings after the stimulation compared with 6 of 20 patients with other renal diseases (30%). The deterioration was significantly more frequent in IgA nephropathy than in other renal diseases (p <0.005). Previous episodes of gross hematuria following upper respiratory tract infections had occurred in 17 of 40 patients who showed deterioration of urinary findings after tonsil stimulation (43%) as against in 4 of 22 without deterioration (18%). The level of serum secretory IgA was higher in patients who showed deterioration of urinary findings after tonsil stimulation than in those who did not show it. Though tonsil stimulation increased blood leucocyte count it did not affect the concentrations of serum IgA or secretory IgA. It is concluded that tonsil stimulation often deteriorates urinary findings in patients with IgA nephropathy; therefore chronic tonsillitis may play a part in the pathogenesis of IgA nephropathy.

Adolescent↗
PubMed1996

Reactive arthritis induced by tonsillitis.

We describe 13 adult patients with reactive arthritis induced by tonsillitis. Arthritis occurred 710 days after tonsillitis and involved the wrists, knees, feet and sternoclavicular joints. Some cases had pain in the Achilles tendon areas. Synovial fluid examined in 4 patients was sterile. All patients except 3 showed unequivocal elevation of serum ASO and/or ASK. Streptococcus was isolated from tonsillar swabs in 7 patients. One had maculopapular erythema and 2 had abdominal pain of unknown origin, but none had cardiac involvement, chorea and subcutaneous nodule. HLA examination revealed that 4 had B39 (p <0.005). Eight cases were treated with antibiotics. Five cases underwent tonsillectomy. All tonsils had cryptic abscess. No exacerbation was seen thereafter. These cases probably represent reactive arthritis induced by tonsillitis and should be distinguished from other rheumatic diseases.

Adult↗
PubMed1996

[Orthostatic hypotension and postprandial hypotension].

Both orthostatic hypotension (OH) and postprandial hypotension (PPH) may result from lesions in any part of the baroreflex arc, which comprises central autonomic network, afferent pathways, efferent pathways, and neuro-vascular junction. Nonetheless, most attention has been centered to the efferent pathways to date. In the present report, I discussed on the contribution of neuro-vascular junction and central autonomic network to the development of OH and PPH. I also referred to the essential difference in pathophysiology between OH and PPH. (1) Difference between OH and PPH: Essential difference is in triggers inducing the initial blood pressure fall. The trigger in OH is gravity, while that in PPH is abnormal release of vasodilative gastroenteric peptides; the former is equally delivered to all persons living on earth, but the latter varies from person to person. (2) Neuro-vascular junction: Previous studies, in which catecholamine drip infusion tests were carried out on patients with OH, suggested that all of cardiovascular alpha-, beta 1, and beta 2 adrenoceptors gain denervation supersensitivity in OH. This view does, however, underestimate the blood pressure buffering effect of baroreflex. Because long-standing alteration in blood pressure by drip infusion of catecholamine necessarily provokes baroreflex, it is reasonable that augmented cardiovascular responses in OH are largely due to baroreflex failure. We performed bolus infusion tests of noradrenaline and isoprenaline on patients with OH, and found that alpha-adrenoceptor-mediated rise in blood pressure was comparable to control, beta 1-mediated increase in heart rate was blunted, and beta 2-mediated fall in blood pressure was enhanced in OH. It is, therefore, likely that beta 2-mediated vasodilation exceeds alpha-mediated vasoconstriction in OH. In such condition, noradrenaline may produce a paradoxical hypotensive effect, which contributes to the development of OH or PPH. (3) Central autonomic network (CAN): Clinical symptoms due to lesions within CAN are usually not manifested when the efferent sympathetic pathways are highly impaired, as in multiple system atrophy. Some variants of OH and PPH may result from lesions within CAN, however. For example, we have experienced a case of sympathotonic OH associated with herpes simplex encephalitis, in which the efferent pathways do not seem to be involved.

Eating↗
PubMed1995

Structural organization and chromosomal assignment of the human obese gene.

The obese (ob) gene has been identified through a positional cloning approach; the mutation of this gene causes marked hereditary obesity and diabetes mellitus in mice. We report here the isolation and characterization of the human ob gene. Southern blot analysis demonstrated a single copy of the ob gene in the human genome. The human ob gene spanned approximately 20 kilobases (kb) and contained three exons separated by two introns. The first intron, approximately 10.6 kb in size, occurred in the 5'-untranslated region, 29 base pair (bp) upstream of the ATG start codon. The second intron of 2.3 kb in size was located at glutamine +49. By rapid amplification of 5'-cDNA ends, the transcription initiation sites were mapped 54-57 bp upstream of the ATG start codon. The 172-bp 5'-flanking region of the human ob gene contained a TATA box-like sequence and several cis-acting regulatory elements (three copies of GC boxes, an AP-2-binding site, and a CCAAT/enhancer-binding protein-binding site). By the fluorescence in situ hybridization technique, the ob gene was assigned to human chromosome 7q31.3. This study should establish the genetic basis for ob gene research in humans, thereby leading to the better understanding of the molecular mechanisms underlying the ob gene.

Amino Acid Sequence↗
PubMed1995

Properties of the voltage-gated calcium channels mediating dopamine and acetylcholine release from the isolated rat retina.

We examined the properties of voltage-gated calcium channels mediating endogenous dopamine (DA) and acetylcholine (ACh) release in the isolated rat retina. Application of 30 mM KCl elicited the release of DA and ACh, and these releases were abolished in Ca(2+)-free medium. The high K(+)-evoked DA release was largely blocked by both of omega-agatoxin IVA and omega-conotoxin MVIIC, P- and Q-type calcium channel antagonists, and partly blocked by isradipine, and L-type calcium channel antagonist, and omega-conotoxin GVIA, an N-type calcium channel antagonist. omega-Agatoxin IVA at a small dose, sufficient to block P-type channels alone, was however without effect. On the other hand, the high K(+)-evoked ACh release was partly blocked by omega-agatoxin IVA and omega-conotoxin MVIIC, but was resistant to isradipine and omega-conotoxin GVIA. Flunarizine, a non-selective T-type calcium channel antagonist, did not inhibit the release of DA and ACh. Cd2+ markedly blocked the release of both DA and ACh, Co2+ and Ni2+ slightly blocked the release of DA, and the release of ACh was not blocked by these two divalent cations. These results suggest that the high K(+)-evoked release of retinal DA is largely mediated by omega-agatoxin IVA and omega-conotoxin MVIIC sensitive calcium channels (probably Q-type channels), while the release of retinal ACh is largely mediated by as yet uncharacterized Cd2+ sensitive calcium channels. The properties of voltage-gated calcium channels involved in the release of ACh in the rat retina differ from those of DA.

Acetylcholine↗
PubMed1995

Characterization of the 5'-flanking region and chromosomal assignment of the human brain natriuretic peptide gene.

Brain natriuretic peptide (BNP) is a cardiac hormone that occurs predominantly in the ventricle, and synthesis and secretion of BNP are greatly augmented in patients with congestive heart failure and in animal models of ventricular hypertrophy. In order to elucidate the molecular mechanisms underlying the human BNP gene expression in the heart, the human BNP gene was isolated from a size-selected genomic minilibrary. The 1.9-kb human BNP 5'-flanking region (-1813 to +110) contained an array of putative cis-acting regulatory elements. Various lengths of the cloned 5'-flanking sequences were linked upstream to the bacterial chloramphenicol acetyltransferase (CAT) gene, and their promoter activities were assayed. The 1.9-kb promoter region showed a high-level CAT activity in cultured neonatal rat ventricular cardiocytes. When the CT-rich sequences (-1288 to -1095) were deleted, the high-level activity was reduced to approximately 30%. The 399-bp BNP 5'-flanking region (-289 to +110) showed approximately 10% activity of the 1.9-kb region. Furthermore, using human-rodent somatic hybrid cell lines, the BNP gene was assigned to human chromosome 1, on which the atrial natriuretic peptide gene is localized. The present study leads to a better understanding of the molecular mechanisms for the human BNP gene expression in the heart.

Animals↗
PubMed1995

Assessment of working skeletal muscle oxygenation in patients with chronic heart failure.

Patients with chronic heart failure (CHF) are frequently limited by muscle fatigue resulting from impaired skeletal muscle blood flow. Accordingly, we assessed working skeletal muscle oxygenation in such patients using near-infrared (NIR) spectroscopy. Nine normal subjects (mean age 52 years) and 12 patients with CHF (mean age 60 years) were studied. NIR spectroscopy was used to monitor relative changes in oxygenated hemoglobin (Hb) and myoglobin (Mb) (oxy Hb/Mb), deoxygenated Hb and Mb (deoxy Hb/Mb), and total (oxy + deoxy) Hb and Mb (total Hb/Mb) contents in the vastus lateralis muscle at rest, during warm-up (0 W, 30 cycles/min for 3 min), incremental maximal supine bicycle exercise (ramp protocol, 15 W/min, 50 cycles/min), and recovery. At peak exercise the patients exhibited reduced heart rate, systolic blood pressure, peak exercise oxygen consumption (VO2; 15 +/- 3.0 ml/kg/min vs 32 +/- 8.5 ml/kg/min), and workload (99 +/- 23.4 W vs 183 +/- 68.4 W) as compared with the normal subjects. The respiratory quotient was comparable in both groups. In the normal subjects, oxy Hb/Mb was increased from the warm-up period to the early phase of exercise, followed by a progressive decrease to peak exercise. In the recovery phase, oxy Hb/Mb was increased abruptly. For these patients, change in oxy Hb/Mb followed a pattern similar to that seen in normal subjects, and oxy Hb/Mb was decreased earlier in contrast to that in the normal subjects. There was a significant difference in the change of oxy Hb/Mb during warm-up, early phase exercise, and recovery between the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Exercise Test↗
PubMed1995

Ultrastructural relation between nerve terminals and dentine bridge formation after pulpotomy in human teeth.

Close association between nerve terminals and preodontoblasts, odontoblasts and predentine was observed during healing after pulpotomy. The nerve terminals frequently contained large numbers of synaptic vesicles. Terminals with many vesicles tended to be fewer in the predentine than in the odontoblastic layer. The distribution of terminals was more dense at the stage before the regenerated odontoblasts became arranged regularly beneath the predentine. It is suggested that these terminals have some efferent role(s), especially during collagen synthesis at the early stage of dentinogenesis. The nerves may release their abundant synaptic vesicles, in addition to serving a sensory role for monitoring the increased sensitivity in the injured areas.

Dentin, Secondary↗
PubMed1995

A saponin conjugated with 2,3-dihydro-2,5-dihydroxy-6-methyl-4H-pyran-4-one from Dolichos lablab.

A new 2,3-dihydro-2,5-dihydroxy-6-methyl-4H-pyran-4-one (DDMP)-conjugated saponin, lablab saponin I, was isolated from the hypocotyl of hyacinth bean (Dolichos lablab). The structure was elucidated by 1H NMR and 13C NMR spectroscopy and chemical techniques as 3-O-[alpha-L-rhamnopyranosyl- (1-->2)-beta-D-galactopyranosyl(1-->2)-beta-D-glucuronopyranosyl(1 -->)]-22-O- [2,3-dihydro-2,5-dihydroxy-6-methyl-4H-pyran-4-one(2'-->)]-3 beta, 22 beta, 24-trihy-droxyolean-12-en-28-al. SOD (superoxide dismutase)-like activity depended upon the DDMP group and the aldehyde group (C-28) of the aglycone was observed in the order of lablab saponin I > glutathione > soyasaponin beta g > maltol. The soybean saponin Bb, lacking the DDMP moiety was found not to exhibit the SOD-like activity.

Carbohydrate Conformation↗
PubMed1995

Membranoproliferative glomerulonephritis associated with hepatitis C virus infection responsive to interferon-alpha.

A 42-year-old man with hepatitis C virus infection, cryoglobulinemia, hypocomplementemia, and nephrotic syndrome is reported. The kidney biopsy showed membranoproliferative glomerulonephritis. The patient was treated with interferon-alpha for 2 months. After the treatment, serum hepatitis C virus RNA became negative and nephrotic syndrome remitted. Repeat biopsy of the kidney revealed an improvement in renal histology. This case confirms an association between hepatitis C virus infection and membranoproliferative glomerulonephritis and the usefulness of interferon-alpha for treatment.

Adult↗
PubMed1995

Preparation of a monoclonal antibody against mouse brain natriuretic peptide (BNP) and tissue distribution of BNP in mice.

1. In order to explore the significance of brain natriuretic peptide (BNP), a cardiac hormone secreted from the ventricle, in mice, we prepared a monoclonal antibody against mouse BNP (mBNP) and established a specific radioimmunoassay (RIA) for mBNP. 2. A monoclonal antibody, KY-mBNP-I, was prepared by the fusion of mouse myeloma cells X63-Ag8.653 with spleen cells of the BALB/c mouse immunized with synthetic mBNP[108-121] conjugated to bovine thyroglobulin. KY-mBNP-I belonged to an IgG2a subclass and showed a high affinity for mBNP (Ka = 1.8 x 10(11) mol/L-1). 3. The RIA established that using KY-mBNP-I was highly sensitive and specific for mBNP, with an IC50 value of 3 fmol/tube and cross-reactivities of less than 0.003% with related natriuretic peptides. mBNP-like immunoreactivity (mBNP-LI) was detected in the mouse atrium (0.35 +/- 0.02 nmol/g), ventricle (20.5 +/- 0.5 pmol/g) and kidney (0.50 +/- 0.05 pmol/g), but not in other tissues including brain. 4. Gel filtration analysis revealed that the major component of tissue mBNP-LI was co-eluted with synthetic mBNP[77-121], a 45-amino acid mature peptide. 5. The monoclonal antibody and RIA for mBNP established here will provide useful tools to investigate the functional significance of BNP in mice, coupled with the genetic engineering approach.

Animals↗
PubMed1995

Molecular cloning of rat obese cDNA and augmented gene expression in genetically obese Zucker fatty (fa/fa) rats.

The obese (ob) gene has recently been isolated through a positional cloning approach, the mutation of which causes a marked hereditary obesity and diabetes mellitus in mice. In the present study, we isolated rat ob cDNA and examined the tissue distribution of the ob gene expression in rats. We also studied the gene expression in genetically obese Zucker fatty (fa/fa) rats. The rat ob gene product, a 167 amino acid protein with a putative signal sequence, was 96 and 83% homologous to the mouse and human ob proteins, respectively. Northern blot analysis using the rat ob cDNA probe identified a single mRNA species of 4.5 kb in size in the adipose tissue, while no significant amount of ob mRNA was present in other tissues in rats. The ob gene was expressed in the adipose tissue with region specificities. The rank order of the ob mRNA level in the adipose tissue was epididymal, retroperitoneal, and pericardial white adipose tissue > mesenteric and subcutaneous white adipose tissue > or = interscapular brown adipose tissue. The ob gene expression occurred in mature adipocytes rather than in stromalvascular cells isolated from the rat adipose tissue. Expression of the ob gene was markedly augmented in all the adipose tissue examined in Zucker fatty (fa/fa) rats at the stage of established obesity. The present study leads to the better understanding of the physiologic and pathophysiologic roles of the ob gene.

Adipose Tissue↗