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Biomedical subjects

Y Asano

Publications and source records attributed to Y Asano.

At least 487 records · Page 27Linked to original sources
PubMed1992

IgM neutralizing antibody responses to human herpesvirus-6 in patients with exanthem subitum or organ transplantation.

The assay for detecting IgM neutralizing (NT) antibody activity to human herpesvirus-6 (HHV-6) was developed by using pretreatment of blood sample with staphylococcal protein A. The activity was mostly present in IgM fractions of serum but not in IgA fractions separated by ultracentrifugation. The assay was used for seroepidemiological studies for HHV-6 infection. In primary HHV-6 infection, IgM NT antibodies appeared 5 to 7 days after onset of exanthem subitum, reached maximum titers at 2 to 3 weeks, and tended to decline to undetectable levels after 2 months. In contrast, reactivation of HHV-6 observed in organ transplants showed somewhat greater degree of IgM NT antibody responses that persisted for 2 to 3 months and became undetectable 5 to 6 months after transplantation. The level and persistence of NT antibody titers measured by the conventional method was generally greater than those of the IgM titers. The prevalence of the IgM NT antibodies was examined in healthy individuals. The antibody was first detected at 4 to 7 months of age (5%), reached maximum level at 8 to 11 months (40%), and was detectable by 4 to 6 years (17%). A few (4 to 5%) of adolescents and adults were positive for the antibody.

Adolescent↗
PubMed1992

Comparison of severity of viremia and antibody responses between infants and children with measles.

Severity of viremia and neutralizing antibody responses were compared between nine young infants (less than or equal to 10 months) with measles and 18 infants and children (greater than or equal to 11 months) with ordinary measles. Peripheral blood mononuclear cell (PBMC)-associated viremia was detected between the first day of elevation of fever (day 0) and day 5 of the disease in the former group, whereas PBMC-associated and cell-free viremia were detected between day 0 and day 14 in the latter group. The number of infected PBMC during the first 7 days of the disease was 3.22 +/- 1.07 (log10, mean +/- s.d.) per 10 million PBMC in the former group, which was significantly smaller (P = 0.02) than that of the latter group (4.21 +/- 1.18). The former group reached the maximum level of antibody earlier than the latter group.

Age Factors↗
PubMed1992

Fatal encephalitis/encephalopathy in primary human herpesvirus-6 infection.

An encephalitic illness with a fatal outcome occurred in a 9 month old girl with virologically confirmed exanthem subitum. Human herpes-virus-6 (HHV-6) DNA was found in the cerebrospinal fluid at the acute stage of the disease by the polymerase chain reaction, but the virus antigen was not detected in her brain tissue. This suggests that HHV-6-induced encephalitis/encephalopathy may be due to a non-infectious process.

Antigens, Viral↗
PubMed1992

Varicella zoster virus DNA in throat swabs of vaccinees.

Ninety throat swabs from 30 healthy children who received varicella vaccine were tested for varicella zoster virus DNA by the polymerase chain reaction. Seroconversion was observed in 27 of 30 (90%) vaccinees. The positive rates were 7.4% (2/27) at one week and 0% (0/27) at four weeks after vaccination. These rates were considerably lower than those in normal children with varicella.

Blotting, Southern↗
PubMed1992

Effect of insulin on potassium secretion in rabbit cortical collecting ducts.

Insulin is known to play an important role in the regulation of extrarenal K homeostasis. Previous clearance studies have shown that insulin decreases urinary K excretion, but the responsible nephron segments have not been identified. In this microperfusion study, in vitro, the effect of insulin on K transport in the cortical collecting duct (CCD), which is thought to be an important segment for regulation of the final urinary K excretion, was investigated. Basolateral insulin (10(-6) M) significantly inhibited net K secretion by 20% (mean JK = -26.2 +/- 4.2 peq.mm-1.min-1 for controls compared with -21.1 +/- 3.4 with insulin, P less than 0.001) and depolarized the transepithelial voltage (VT, from -14.6 +/- 3.5 to -10.8 +/- 3.5 mV, P less than 0.005), recovery did not occur over 60 min. Insulin (10(-11)-10(-5) M) depressed K secretion and depolarized the VT in a concentration-dependent manner. The half-maximal concentration was 5 x 10(-10) M, which is within the physiological range of plasma insulin concentration. In tubules of deoxycorticosterone acetate-treated rabbits, insulin also produced a significant fall in K secretion (from -43.4 +/- 7.5 to -36.1 +/- 5.7 peq.mm-1.min-1, P less than 0.05). Although luminal Ba (2 mM) decreased K secretion (from -14.4 +/- 2.9 to -7.0 +/- 1.7 peq.mm-1.min-1), basolateral insulin (10(-6) M) inhibited K secretion further (to -4.7 +/- 1.3 peq.mm-1.min-1, P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Amiloride↗
PubMed1992

Interaction of Cl- and other halogens with Cl- transport systems in rabbit cortical collecting duct.

We have reported that in the rabbit cortical collecting duct (CCD) we can identify electrophysiologically three distinct cell types; the collecting duct (CD) cell and the alpha- and beta-intercalated (IC) cell. To further characterize the Cl- transport properties of each cell type, we examined the interaction between Cl- and other halogens or SCN- in the isolated and perfused CCD by intracellular microelectrode impalement. The rapid depolarization of the basolateral membrane potential (VB) caused by replacement of bath Cl- with each anion revealed that the sequences of apparent halogen selectivity for the basolateral Cl- conductance were similar in all three cell types. The ranking of Cl- > Br- > F- > I- corresponds to the sequence 5 of Eisenman's series, indicating "strong" interaction of the anions with the selectivity site. The basolateral Cl- conductance of these three cell types may share common characteristics, although I- permeability is less in IC cells than in CD cells. Hyperpolarization of the basolateral membrane of the beta-IC cell upon reduction of luminal Cl- reflects alterations in either Cl- entry across the apical membrane, or Cl- exit across the basolateral membrane, or both. Luminal Cl- replacement with each anion showed that the sequence of the hyperpolarization of the basolateral membrane was I- >> cyclamate = SCN- > F- > Br-, suggesting that I-inhibits either apical Cl- entry or basolateral Cl- exit. On the other hand, in the CD cell reduction of the perfusate Cl- by replacement with each anion caused the basolateral membrane to hyperpolarize with a different ranking: cyclamate = F- > I- = SCN- > Br-.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Measurement of blood flow in the parameatal foreskin flap for urethroplasty in hypospadias repair.

During the one-stage repair of hypospadias the blood flow of the parameatal-based foreskin flap was measured in 30 patients by using laser Doppler velocimetry. The mean blood flow in the penile foreskin was estimated to be 15 ml/min/100 g and it increased to 150-200% after the induction of anesthesia, and then decreased to 72% at the tip of the created parameatal foreskin flap. Topical application of papaverine hydrochloride restored the flow to the preincision level in half of the cases. The parameatal foreskin flap, both in the form of a manta-wing and in extended circumferential form, appears to have an enough microcirculation suitable for one-stage repair (OUPF II and OUPF IV, respectively) of hypospadias.

Child↗
PubMed1992

Effects of uninephrectomy on electrical properties of the cortical collecting duct from rabbit remnant kidneys.

Microelectrode techniques were used to determine the Na+ and K+ transport properties of the collecting duct cell in the isolated cortical collecting duct (CCD) from rabbits 14 d after uninephrectomy (UNX); results were compared with those from sham-operated rabbits (control). UNX had no effects on plasma aldosterone levels. The CCDs from UNX rabbits exhibited structural hypertrophy. The lumen negative transepithelial voltage and the basolateral membrane voltage (VB) were elevated in the UNX group. Although the transepithelial conductance (GT) and the fractional apical membrane resistance (fRA) were not different between the two groups, the conductances of the apical and the basolateral membranes were increased, and the tight junction conductance was decreased in the UNX group. The amiloride-sensitive changes in apical membrane voltage (VA), fRA, and GT were greater in the UNX group. The changes in VA upon raising the perfusate K+ concentration and the changes in VA and GT upon addition of Ba2+ to the perfusate were elevated in the UNX group. Upon raising K+ in the bath, a large depolarization of VB was observed in the UNX group. Lowering the bath Cl- resulted in a small depolarization of VB in the UNX group. Addition of Ba2+ to the bath in the UNX group caused the VB to hyperpolarize in parallel with decreases in GT and fRA whereas in the control group it had no effect on VB. Addition of ouabain to the bath resulted in a large depolarization of VB in the UNX group. We conclude that (a) UNX stimulates conductances of Na+ and K+ in the apical membrane, active Na(+)-K+ pump activity, and K+ conductance in the basolateral membrane, independently of plasma aldosterone; (b) The basolateral membrane in the tubules of UNX rabbits is more selective to K+; and (c) the hyperpolarization of VB upon UNX may increase passive K+ entry into the cell across the basolateral membrane.

Aldosterone↗
PubMed1992

Stimulation of Na+/H+ exchange induced by angiotensin II in cultured rat vascular smooth muscle cells: role of Ca2+ and C-kinase.

Changes in cytosolic calcium concentration ([Ca2+]i) have been implicated in the regulation of intracellular pH (pHi) in several cell types. In the present study we investigated the regulatory mechanism of Na+/H+ exchange induced by angiotensin II (AII) in cultured rat vascular smooth muscle cells (VSMCs). Serially passaged VSMCs from Sprague-Dawley rat thoracic aorta were grown on coverslips and loaded with the pH-sensitive fluorescent indicator 2',7'-bis-(carboxyethyl)-5,6-carboxyfluorescein (BCECF). In HCO(3-)-free Ringer solution, pH 7.40, the resting pHi was 7.21 +/- 0.02 (n = 21). A biphasic response was seen after exposure of these cells to AII: an initial transient a acidification, followed by sustained alkalization. The magnitude of alkalization was dose-dependent. AII-mediated acidification was completely inhibited by [Sar1-IIe5-Gly8]AII, but amiloride had no effect. In contrast, the alkalization induced by AII was abolished by both amiloride and Na(+)-free medium. In Ca(2+)-free medium, the AII-induced alkalization was partially blocked and verapamil also caused partial inhibition. Since AII activates phospholipase C in VSMCs, we examined whether AII would increase Na+/H+ exchange by activation of protein kinase C. An inhibitor of protein kinase C, 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7), partially inhibited the alkalization induced by AII. These results indicate that AII stimulates cytoplasmic alkalization via an amiloride-sensitive Na+/H+ exchange system in cultured rat VSMCs, and that this AII-stimulated Na+/H+ exchange is mediated by Ca(2+)-dependent and protein kinase C-dependent mechanisms.

Amiloride↗
PubMed1992

Postnatal behavioral development in methylazoxymethanol-induced microcephalic rats--a behavioral teratology study.

Behavioral testings in methylazoxymethanol (MAM)-induced microcephalic rats were conducted. Pregnant Sprague-Dawley rats were treated intraperitoneally with 0, 20 or 40 mg/kg of MAM once a day on day 14 of gestation and were allowed to delivery. Male pups from each litter were examined for open field test at 6 weeks of age and shuttle-box avoidance test at 7 weeks or more of age. In the open field activity of pups, the counts of ambulation and locomoting distance in 40 mg/kg group have increased significantly as compared with those in control group. In the shuttle-box avoidance test, the avoidance response rate was dose-dependently high in the session of the 1st day. As to the interaction between the avoidance response rate and sequence of sessions, however, the avoidance response rate in 40 mg/kg group was significantly low. Rate of the rats with errors and number of response during the intertrial interval was significantly high in 40 mg/kg group. Thus, we could demonstrate functional disturbance in the memory retaining ability in utero MAM-exposed rats.

Abnormalities, Drug-Induced↗
PubMed1992

Renal potassium wasting in distal renal tubular acidosis: role of aldosterone.

The pathogenesis of renal potassium wasting and hypokalemia in classic renal tubular acidosis (type 1 RTA) remains uncertain. The prevailing theory is that K(+)-Na+ exchange is stimulated due to an inability of the distal tubule to establish a normal steep lumen-peritubular H+ gradient. We encountered a 42-year-old woman with type 1 RTA associated with Sjögren's syndrome, in whom renal potassium wasting and hypokalemia persisted despite sustained correction of systemic acidosis with alkali therapy and increased intake of potassium. In addition, plasma renin activity was markedly increased and the serum aldosterone level was upper-normal despite the hypokalemia. Increased intake of sodium resulted in suppression on the serum aldosterone and correction of renal potassium wasting and hypokalemia. This case shows that secondary hyperaldosteronism, possibly due to an impairment of sodium conservation in the distal tubule, may contribute to the loss of potassium from the distal tubule even after the correction of acidosis.

Acidosis, Renal Tubular↗
PubMed1992

Human herpesvirus-6 infection and bone marrow transplantation.

Human herpesvirus-6 (HHV-6) is ubiquitous in the human population and causes exanthem subitum, a benign disease seen in infancy. However it also produces a wide spectrum of clinical manifestations including cases with a fatal outcome. The virus remains latent in several organs, including the kidneys, liver, lymph/nodes and salivary glands, after the primary infection and reactivates when immune function is impaired. Reactivation of the virus occurred in a half of the bone marrow recipients 2 to 4 weeks after bone marrow transplantation (BMT). It remains to be established whether HHV-6 in fact causes the fever and rash observed in recipients who have reactivation of the virus. The data reviewed here will be required to compare with those of human herpesvirus 7 and a different group of HHV-6.

Adolescent↗
PubMed1992

[Progressing cases from low tone sudden deafness to Menière's disease--cochlear impairment in the so-called pre-Menière's disease period].

Among 80 patients with low tone sudden deafness (LTSD) who visited our department over the past 15 years, there were 6 cases (7.5%) who subsequently progressed to Menière's disease. The clinical and audiological processes of the 6 patients were studied in detail and the following results were obtained. (1) In these 6 patients, the time between onset of LTSD and the diagnosis of Menière's disease ranged from 4 months at the shortest to 6 years and 8 months at the longest, 2 years and 9 months on average. (2) Two pattern types were seen in the change from LTSD to Menière's disease: changing within a short period of time after recurrence of an LTSD-like attack, and changing after more than one year without recurrent attack. (3) The monoattack-nonrecovered type of LTSD and the recurrent type of LTSD within three months after the onset (short-term prognosis) frequently progressed to Menière's disease. (4) There were no close relationships between subjective symptoms and audiological features in the pre-Menière's disease period (from the onset of LTSD to the recurrence of vertigo with cochlear symptoms). (5) The 6 patients showed various audiogram shapes at the time of progression to Meniere's disease; 3 cases with the slightly rising type, 1 with the high frequency-impaired type, and 2 with the moderate, gradual and flat type. (6) Of the 6 patients, 3 had good hearing during long term observation. At least 2 patients seemed to have the mild type of Menière's disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

[Surgical outcome of 32 cases in traumatic subdural hygroma].

32 cases of traumatic subdural hygroma (TSH) in adults with surgical treatment were retrospectively investigated by means by clinical features and CT findings. The cases consisted of 29 males and 3 females, aged 41 to 87 years (mean 69). Preparative CT scan of all cases revealed low density area and crescent shape in frontotemporal or frontoparietal subdural space. Half of the cases had bilateral lesions. At operation of TSH, color of subdural fluid collections was more water clear or xanthochromic than bloody. As a results, 22 out of 32 cases (69%) in TSH improved with surgical treatment. Many of effective cases of surgical treatment in TSH had short interval from trauma to operation and light disturbance of consciousness before operation. However, the other intracranial damage will also affect the clinical outcome of TSH, because the majority of cases in this study was accompanied by an intracranial damage including cerebral contusion, subarachnoid hemorrhage or intracranial hemorrhage. Nevertheless, surgical management for TSH was so effective that the operation should be undergone sooner interval from trauma, simultaneously considering the another intracranial lesions except TSH. But then, we experienced 7 cases (22%) of ventricular dilatation and 5 cases (16%) of chronic subdural hematoma in postoperative follow up CT scans. In 5 cases among the former, ventriculoperitonial shunt was done, and in 3 cases among the latter, burr hole evacuation was performed. Therefore, the postoperative course of TSH should require careful observation by CT scan and so on.

Adult↗
PubMed1992

Human herpesvirus-6 DNA in cerebrospinal fluid of a child with exanthem subitum and meningoencephalitis.

The involvement of human herpesvirus-6 (HHV-6) and herpes simplex virus infections was evaluated virologically and serologically in a 13-month-old girl with meningoencephalitic illness occurring in the pre-eruptive stage of exanthem subitum. An isolation of HHV-6 from blood and seroconversion to the virus confirmed the primary infection with the virus. HHV-6 gene sequences were detected in cerebrospinal fluid of acute stage of the disease by polymerase chain reaction. There was no evidence of herpes simplex virus infection in blood and cerebrospinal fluid. The patient recovered from the disease without any sequelae, although abnormal electroencephalography and cerebral computed tomography findings were observed temporally in the acute stage of the disease. These findings strongly suggest that HHV-6 invades the central nervous system and causes meningoencephalitis.

Antibodies, Viral↗
PubMed1992

Effect of antiinflammatory agents on synthesis of MCP-1/JE transcripts by human blood monocytes.

The human monocyte chemoattractant protein (MCP)-1 encoded by the JE gene belongs to a family of low molecular weight secretory cytokines with monocyte-stimulating activity. JE transcripts are constitutively synthesized by normal and leukemic monocytes, as well as mesenchymal cells, including fibroblasts, vascular endothelial cells, and smooth muscle cells. Expression of MCP-1/JE is increased severalfold upon exposure of cells to recombinant human granulocyte-macrophage colony-stimulating factor but is down-regulated when cells are treated with lipopolysaccharide (LPS). Given the proinflammatory properties of MCP-1/JE, we have examined the modulatory effects of various antiinflammatory agents, including indomethacin, dexamethasone, cyclosporin A, and interleukin-4, on levels of MCP-1/JE transcripts either constitutively or inducibly expressed by human peripheral blood monocytes. Whereas indomethacin had no detectable effect on synthesis of MCP-1/JE transcripts and interleukin-4 treatment resulted in only a modest increase in steady state JE mRNA levels, exposure of monocytes to dexamethasone (DXS) led to a significant (2.5-10-fold) down-regulation of MCP-1/JE transcript levels. Studies examining the mechanism of down-regulation of JE mRNA by DXS indicated that DXS was acting transcriptionally and posttranscriptionally, by reducing the transcriptional rate of the MCP-1/JE gene and by destabilizing JE mRNA, a process requiring de novo RNA and protein synthesis. Although cyclosporin A by itself had no effect on synthesis of JE transcripts, it apparently relieved LPS-mediated down-regulation of JE transcript levels, by interfering with the destabilizing effect of LPS on JE mRNA. These results may provide new information regarding the action of antiinflammatory agents on synthesis of endogenous proinflammatory cytokines.

Anti-Inflammatory Agents↗