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Biomedical subjects

H Hayashi

Publications and source records attributed to H Hayashi.

At least 829 records · Page 46Linked to original sources
PubMed1994

Pelvic fascia strength in women with stress urinary incontinence in comparison with those who are continent.

Biophysical properties of the anterior vaginal wall as well as the rectus fascia were evaluated in vivo by penetrating the Stamey needle into these tissues of 26 female patients with stress incontinence in comparison with those of 21 continent subjects. The results demonstrated that shear strength of the anterior vaginal wall was lower in incontinent patients than in continent subjects (P < 0.01). Shear strength of the rectus fascia in the patients, which was not supposed to be related to urinary incontinence and should have had the same strength as the control subjects, was also found to be lower than the control (P < 0.01). Shear strength of the vaginal wall was not correlated with age irrespective of their continence status (P > 0.05). Based on our findings it is concluded that some women suffering from stress incontinence may have a hereditary disorder of biophysical properties of the tissues.

Adult↗
PubMed1994

Isoform transition of contractile proteins related to muscle remodeling with an axial gradient during metamorphosis in Xenopus laevis.

For clarification of the mechanism of hormonally and spatially regulated larval-to-adult conversion of skeletal muscle, changes in the expression of muscle contractile proteins were examined during metamorphosis of Xenopus laevis. Analysis by electrophoresis revealed that isoforms of myosin heavy chain (MHC) switched from larval to adult type and adult-specific beta-tropomyosin (TM) appeared during metamorphosis in addition to preexisting alpha-TM. Distinct regional differences in isoform transition were apparent. Isoform changes started at stage 54 in the hindlimb and at stage 57 in the body. However, no change in the tail occurred. Immunohistochemical examination was performed to analyze isoform transition in dorsal body muscle. Before metamorphosis (stage 53), only a small number of muscle fibers at the dorsomedial part of dorsal muscle expressed "adult-type" muscle proteins. During metamorphosis the adult-type area gradually expanded from dorsal to ventral slides with an anteroposterior gradient with increase in adult-type (adult-type MHC and beta-TM-positive) muscle fibers. Thus, there is a gradient in isoform transition. In addition, adult-type fibers showed smaller diameter than larval-type fibers and DNA synthesis occurred in dorsal muscle with an anteroposterior gradient before the isoform transition, suggesting that new myogenesis of adult-type fibers proceeds with a gradient during metamorphosis. Also, degenerating fibers were observed only in the larval-type area. These results suggest that isoform transition is achieved by new proliferation of adult-type myoblasts and death of preexisting larval-type fibers, not by change in gene expression within the same cell.

Animals↗
PubMed1994

Activation tagging: a means of isolating genes implicated as playing a role in plant growth and development.

Activation T-DNA tagging has been used to generate a variety of tobacco cell lines selected by their ability to grow either in the absence of auxin or cytokinin in the culture media, or under selective levels of an inhibitor of polyamine biosynthesis. The majority of the cell lines studied in detail contain single T-DNA inserts genetically co-segregating with the selected phenotype. While most of the plants regenerated from the mutant cell lines appear phenotypically normal, several display phenotypes which could be inferred to result from disturbances in the content, or the metabolism, of auxins and cytokinins, or polyamines. The tagging vector is designed to allow the isolation of tagged plant genes by plasmid rescue. Confirmation that the genomic sequence responsible for the selected phenotype has indeed been isolated is provided by PEG-mediated protoplast DNA uptake of rescued plasmids followed by selection for protoplast growth under the original selective conditions. Several plasmids have been rescued from the mutant lines which confer on transfected protoplasts the ability to grow either in the absence of auxin or cytokinin in the culture media, or under selective levels of an inhibitor of polyamine biosynthesis. This review describes the background to activation tagging and our progress in characterizing the genes that have been tagged in the mutant lines we have generated.

Cytokinins↗
PubMed1994

Greater number of microtubules per axon of unmyelinated fibers of mutant quails deficient in neurofilaments: possible compensation for the absence of neurofilaments.

Morphometric evaluations were performed on the peroneal nerve from mutant quails deficient in neurofilaments (NF) to elucidate the effect of an absence of NF on unmyelinated axons. The diameter frequency distribution of unmyelinated axons was similar between controls and mutants. The mean transverse axonal area, axonal circumference and circularity index of the unmyelinated axons were also similar in controls and mutants. However, the number of microtubules (MT) per axon was greater (P < 0.01) in the mutants than in the controls. The regression analysis relating the number of MT per axon to the diameter of unmyelinated axons indicated a greater number of MT in the mutants than in the controls (P < 0.05-0.01). A significantly greater number of MT per axon in the mutants may suggest a compensatory increase of MT in the absence of NF. This may conserve the size and transverse circular profile of the unmyelinated axons which are probably maintained by both MT and NF in the controls. The number of MT may be increased at the expense of the soluble fraction of tubulin.

Animals↗
PubMed1994

Curative local control of malignant tumors in the acetabulum by intraoperative radiotherapy.

As treatment for malignant tumors in the acetabular region of the pelvis, radiotherapy, mainly in the form of intraoperative radiotherapy (IORT), was carried out in four patients. One had a malignant fibrous histiocytoma of bone and three had metastatic tumors from the stomach and lung. Over follow-up period, ranging from 3 to 46 months, satisfactory limb function was preserved in three patients; the fourth suffered from femoral nerve palsy as a complication of IORT. Cessation of growth was observed radiologically in all the tumors, and curative local control was proven histologically in two patients at autopsy.

Acetabulum↗
PubMed1994

Left ventricular function in asthmatic children chronically treated with theophylline evaluated by exercise Doppler echocardiography.

To evaluate the chronic effects of theophylline on cardiac function, M-mode and pulsed Doppler derived variables were measured at rest and the suprasternal continuous wave Doppler measurement of ascending aortic flow was used during treadmill exercise testing. Subjects consisted of 13 children with stable asthma (mean 11.7 +/- 2.2 years) who were treated with theophylline for at least one year and 16 age-matched, untreated normal volunteers. In the resting state, the chronic administration of theophylline seemed to produce a slight increase in percent fractional shortening, outflow peak velocity and atrial contribution to ventricular filling in the asthmatic children as compared to normals, but these changes were not statistically significant. The asthmatic children showed significantly lower values than the controls in exercise induced changes in the peak velocity, stroke index and cardiac index, but not in the heart rate. Therefore, chronic administration of theophylline appears to have a minimal effect on resting cardiac function, but a possibly deleterious effect on the cardiac response to exercise testing.

Adolescent↗
PubMed1994

Correlation between serum levels of alanine aminotransferase and ferritin in male blood donors with antibody to hepatitis C virus.

Chronic hepatitis C has been demonstrated to be associated with hepatic iron overload, and the hypothesis that the disease activity of hepatitis C is associated with iron cytotoxicity was tested in male volunteer blood donors. Sera with either antibody to hepatitis C virus or hepatitis B surface antigen were selected for determination of ferritin concentration and alanine aminotransferase activity. A correlation between serum ferritin concentration (Y; microgram/l) and alanine aminotransferase activity (X; IU/l) was found in donors with antibody to hepatitis C (log Y = 0.65 x log X + 0.98, r = 0.53, and P < 0.01). The correlation was lower in donors with hepatitis B surface antigen (r = 0.37; P < 0.01). Hepatitis C virus infection probably induces time-dependent iron accumulation associated with the progression of disease activity, while hepatitis B virus infection results in a variety of iron loads with different clinical features. The high disease activity related to hyperferritinemia suggests the presence of iron-induced liver damage in donors with hepatitis C.

Adult↗
PubMed1994

Physiological properties of periodontal mechanosensitive neurones in the trigeminal (Gasserian) ganglion of the rat.

Periodontal mechanosensitive (PM) primary afferent neurones were recorded from the rat trigeminal ganglion and their response to mechanical tooth stimulation studied. The majority (95%) of PM afferents were single-tooth units and most were sensitive to mechanical stimulation of the incisor. They had a sustained response to pressure applied to the tooth, and showed a directional selectivity to the stimulation. Only a small number (5%) of units were multi-tooth sensitive; their receptive fields were restricted to the molars. When the incisor was stimulated mechanically in 12 directions in a plane perpendicular to the axis of the tooth crown, the predominant response fields of the PM units were of the medium type (90-180 degree response angle) or the broad type (180-360 degrees). Each unit had single optimal stimulus direction oriented predominantly in the rostrocaudal or caudorostral direction. About 60% of the PM units responded to tooth stimulation at irregular spike intervals, whereas the remaining 40% fired at relatively regular intervals. When the tooth was stimulated at a force of 0.05 N, the mean spike interval and rate of spike-interval fluctuation [percentage of the standard deviation (SD) of the interval distribution to the mean interval (mean); SD/mean x 100] were 29.2 ms and 38.1% for the regular-interval units, and 15.1 ms and 8.8% for the irregular-interval ones. The mean spike interval of the regular units was significantly longer than that of the irregular ones.

Animals↗
PubMed1994

Extended palmar advancement flap with V-Y closure for finger injuries.

The technique of using volar advancement flaps with V-Y closure to the fingers is described. It is possible to perform volar flap advancements up to 15 mm and use V-Y closures in the distal palm, avoiding a skin graft. This method is based on knowledge of the vascular anatomy of the finger dorsum, to avoid devitalising dorsal skin. This method was applied to 14 fingers of 13 patients including finger amputations, claw nail deformities, and skin defects of the middle phalanx. Favourable results were observed.

Adolescent↗
PubMed1994

Circulatory collapse and sudden death in respirator-dependent amyotrophic lateral sclerosis.

Circulatory collapse and sudden death was defined retrospectively as one of the major critical problems among 23 respirator-dependent patients with amyotrophic lateral sclerosis (ALS). Six cases died from sudden cardiac arrest or anoxic encephalopathy following the circulatory collapse. In five among the six cases, sudden death or cardiac arrest occurred during sleep at night. Eight cases had had episodes of marked fluctuation of blood pressure before death, including paroxysmal elevation of blood pressure and heart rate, and successive sudden pressure fall without compensatory tachycardia. The spells of hypotension often occurred during sleep. In addition, the prospective study of diurnal variation of blood pressure, heart rate, plasma norepinephrine and plasma renin activity in nine respirator-dependent ALS patients showed continuous tachycardia and more remarkable nocturnal decrease of blood pressure compared with the control subjects. Plasma norepinephrine levels were constantly higher in the ALS patients particularly in a daytime. These indicate the continuous sympathetic hyperactivity in ALS. We discuss the cause of the circulatory collapse and sudden death in the respirator-dependent ALS patients in terms of the autonomic dysregulatory mechanism or the sympathetic hyperactivity.

Adult↗
PubMed1994

Participation of the limbic system and its associated areas in the dementia of amyotrophic lateral sclerosis.

The topographic distribution of degenerative changes in large brain sections from five sporadic amyotrophic lateral sclerosis (ALS) patients with dementia and three without dementia was examined. The dementia characteristics were impaired shifting from one line of thinking to another, perseveration, and emotional disinhibition as well as impairment of cognition, and judgment. Neuropathological examinations showed definite ALS changes in all the patients studied. In addition, the five patients with dementia showed neuronal loss, gliosis, and sponginess of the superficial layers throughout the cerebral cortices, predominantly in the dorsomedial cortex of the temporal tip and the parahippocampal, ambiens, anterior cingulate, rectal, orbital, and insular gyri as well as neuronal loss in the basolateral nucleus of the amygdala, nucleus accumbens, and subiculum of the hippocampus. Ubiquitin-immunoreactive inclusions were present in some neurons in the granular cell layers of the hippocampus. Fibrous gliosis was extensive in the subcortical and deep white matter of the frontotemporal lobes. The affected regions take in the limbic system and its associated areas which are the sources of the psychological problems, including emotional disturbance, experienced by these ALS patients. The psychological problems of ALS need to be investigated in relation to the involvement of the limbic system.

Adult↗
PubMed1994

Biotinyl C-terminal-extended motilin as a biologically active receptor probe.

The synthesis, purification, and characterization of biotinylated analogues of motilin are reported. The C-terminal of canine motilin was extended by the addition of a cysteine residue, and then biotinylated. Biotinyl motilin was purified by following HPLC and characterized by amino acid analysis. Biotinylation of the ligand was confirmed by ELISA assay with the avidin-biotin system. Biotinyl motilin showed similar affinity for binding to rabbit gastric membrane fraction compared to unlabeled canine motilin, and also retained functional activity in its ability to cause contraction of rabbit duodenal segments. To determine the binding of biotinyl motilin in isolated rabbit antral smooth muscle, cells were incubated with the biotinyl motilin with and without excess of unlabeled motilin. Subsequent addition of avidin-biotinylated peroxidase complex showed the distribution of reaction products over the cell surface. Bioactive biotinyl motilin provides a useful probe for the demonstration of cell surface motilin receptors and will facilitate receptor purification and characterization.

Amino Acid Sequence↗
PubMed1994

Beneficial or adverse effects of hepatectomy vs. ethanol injection therapy in RBT-1 carcinoma of the rat liver.

In an attempt to ascertain the possible beneficial or adverse effects of ethanol injection into a hepatic malignant tumor, we carried out a series of experiments using the RBT-1 carcinoma. Ten days after the inoculation of RBT-1 carcinoma into the rat livers, the animals were separated into four groups: group A received a sham operation, group B had ethanol injections directly into the hepatic tumor, group C underwent tumor removal and group D underwent tumor removal 20 min after ethanol injection. When a comparison was made with all groups, survival time was significantly longer in group B than in A (p < 0.01), group C than A (p < 0.01) and group C than B (p < 0.01). The incidence of vascular permeation of liver tumor cells into the hepatic vein was significantly higher in group D than C (p < 0.05). Twenty days after initial injection of RBT-1 tumor, 10 rats in each group were killed, and their lungs were assessed for evidence of metastatic spread of tumor. The number of metastatic nodules in the lungs was significantly increased in those rats that had undergone intrahepatic ethanol injection vs. those that had not (group B vs. A [p < 0.05] and group D vs. C [p < 0.05]). The number of metastatic nodules in the lungs differed significantly in those rats that had undergone hepatectomy vs. those that had not. These results are taken to mean that hepatectomy and ethanol injection into a tumor was an effective therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Fluorescence imaging of intracellular Ca2+.

The measurement of intracellular Ca2+ concentrations ([Ca2+]i) is of critical importance, because many cellular functions are tightly regulated by [Ca2+]i. The fluorescent indicator, fura-2, has been used frequently to measure [Ca2+]i because of its sensitivity and specificity, and because it can be loaded into living cells with little disruption of function. Most importantly, the peak excitation wavelength of fura-2 changes when it binds Ca2+. As a consequence, measurements of fluorescence at two excitation wavelengths can be used to obtain an estimate of [Ca2+]i that is independent of dye concentration and cell thickness. Fura-2 acetoxymethyl ester (AM) is a lipid-soluble derivative that is often used because of its ability to pass through cell membranes. There are, however, several problems with the use of fura-2 AM such as intracellular compartmentation and incomplete deesterification. The availability of low-light-level cameras and computer hardware for the digitization of fluorescent images has made quantitative fluorescence microscopy possible. This technique has shown a striking spatial heterogeneity of [Ca2+]i in a variety of cell types, and has revealed substantial new information on dynamic intracellular biochemistry and signal transduction. However, the current imaging technology is not fully developed because of dye and instrumentation limitations. Further development of techniques and new probes are required to improve temporal and spatial resolution.

Animals↗
PubMed1994

Hypobaric-hypoxic exposure and histochemical responses of soleus muscle fibers in the rat.

Hypoxia-acclimatized rats had a higher percentage of fast-twitch oxidative glycolytic fibers and a lower percentage of slow-twitch oxidative fibers in the soleus muscle than age-matched normoxic-rats. However, there was no difference in the fiber type composition of the soleus muscle between hypoxic- and normoxic-male rats after hypoxic-rats were bred at the sea level atmospheric pressure for 5 weeks. Therefore, it is suggested that a higher percentage of fast-twitch oxidative glycolytic fibers in the muscle is found only under hypoxic conditions and is due to an acute response to hypoxia.

Animals↗
PubMed1994

Hepatitis C infection unrelated to blood transfusion in hemodialysis patients.

Hepatitis C virus antibodies were studied using both the 1st and 2nd generation tests in 485 patients who were on maintenance hemodialysis. One hundred and eighty-seven tested positive for antibodies (38.6%); 139 of them had a history of past blood transfusion. There was a crude correlation between the amount of blood given and the antibody positivity rate among those who had a history of blood transfusion. Of 152 patients who had no blood transfusion history, 48 or 31.2% were positive for the antibodies. The length of the period during which these patients had undergone dialysis was closely correlated with the positivity rate; 50% of those who had been on dialysis for more than 10 years were positive for anti-HCV. The positivity rate among the new dialysis patients with chronic renal failure as the control was 4.6%. The difference may be accounted for by nosocomial hepatitis C virus infection. It appears that with two new needle holes made along the anastomosed blood vessels two to three times a week, the chances of patient exposure to hepatitis C virus may increase with time.

Adolescent↗
PubMed1994

New teleocidin-related metabolites, (-)-7-geranylindolactam V and blastmycetin F, from Streptoverticillium blastmyceticum.

Two new teleocidin-related metabolites, (-)-7-geranylindolactam-V [2] and blastmycetin F [3], were isolated from fermentation broths of the actinomycete Streptoverticillium blastmyceticum NA34-17, and their structures were determined by spectroscopic methods. Compound 2 bound strongly to phorbol ester receptors in a mouse epidermal particulate fraction, suggesting that it is a potent in vivo tumor promoter comparable to teleocidins A-1 [4] and B-4 [5].

Animals↗