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Biomedical subjects

Y Murakami

Publications and source records attributed to Y Murakami.

At least 793 records · Page 44Linked to original sources
PubMed1989

Random segregation of DNA strands in epidermal basal cells.

According to the hypothesis proposed by Cairns, stem cells retain the older of the two parental DNA strands, whereas differentiating daughter cells receive the newly synthesized strand, so that a set of "immortal strands" persists in stem cells through successive cell divisions. To test this hypothesis, five successive divisions were induced in basal epidermal cells in vivo by two injections of cholera toxin into mouse skin and cells labeled with [3H]thymidine at the first cell cycle were chased for 50 days. If selective segregation occurs, the labeled strand should be transferred into a non-stem daughter cell after the second division and labeled cells would eventually be eliminated from the epidermis. However, the results suggest random segregation of DNA strands in epidermal basal cells. Labeled basal cells were persistently present throughout the whole epidermis for 50 days. Furthermore, labeled mitotic cells were found after the third division and their numbers of grains decreased exponentially through 5 cycles of divisions.

Animals↗
PubMed1989

[Legionella dumoffii and Legionella pneumophila serogroup 5 isolated from 2 cases of fulminant pneumonia].

We encountered two cases of legionella pneumonia which ran a dramatic course and isolated Legionella dumoffii from one patient and Legionella pneumophila serogroup 5 from the other patient. The patient from whom L. dumoffii was isolated was a 59-year-old male with no basic disease. He presented chill, fever, coughing and other symptoms, starting on July 3, 1986, his disease was diagnosed as pneumonia at the clinic of his company. The patient was then introduced and admitted to our hospital. On admission chest radiography disclosed zonal pneumonia with an unclear border in the right superior lobe of the lung; a beta-lactam preparation was administered, but no effect was obtained and the lung lesion showed a rapid advance. From this condition, we suspected legionella pneumonia and changed the therapy to treatment with erythromycin and rifampicillin. Despite this, no improvement occurred and the patient died on the 26th hospital day. Colonies like Legionella colonies were separated from a total of seven specimens of biopsy aspirated matter from the airway and autopsy collected lung abscess and tracheal secretions, and the bacterium was identified L. dumoffii based on the biochemical and serological properties. In addition, the patient's serum was found to have an increased antibody titer against L. dumoffii. Based on these findings, the patient's disease was diagnosed as pneumonia as caused by L. dumoffii, a relatively rare bacterium as a member of the genus Legionella. The patient from whom Legionella pneumophila serogroup 5 was isolated was an 81-year-old man with basic diseases such as heart failure, anemia and hypothyroidism. He presented fever, general fatigue, anorexia and other symptoms, starting around June 2, 1987; pneumonia was suspected and the patient was urgently admitted to our hospital. The patient died of pneumonia of unknown cause on the second hospital day. To clarify the cause, autopsy was conducted; a large number of colonies like Legionella colonies were noted in the lung tissue. Identification test was then conducted and the bacterium was identified as L. pneumophila; we concluded that the patient's pneumonia had been caused by the identified bacterium L. pneumophila. The isolate was further subjected to slide agglutination test and identified as L. pneumophila serogroup 5.

Aged↗
PubMed1989

Genetic suppression of a dnaG mutation in Escherichia coli.

Escherichia coli strains with a temperature-sensitive mutation, dnaG2903, in the primase-encoding gene spontaneously reverted to the temperature-insensitive phenotype at a high frequency. Many of the reversions were caused by extragenic sdg suppressors. About 100 independently isolated sdg suppressors were analyzed. They fall into two classes. The sdgA mutations were genetically mapped very close to and upstream of the dnaG gene and were found to be cis dominant. DNA sequencing of two of them revealed that G----A and C----A base substitutions had occurred 43 and 62 bases, respectively, upstream of the dnaG start codon. This region represents a transcriptional terminator thought to contribute to control of dnaG gene expression. The other class of suppressor, sdgB, seemed to comprise mutant alleles in the rpoB gene coding for the beta subunit of RNA polymerase core enzyme. Some of them were initially isolated as rifampin-resistant mutants. Both the sdgA and sdgB suppressors were found to increase the transcriptional activity of dnaG. This finding and other observations led to the proposition that sdgA and sdgB suppress the phenotype caused by dnaG2903 by overproducing the mutated primase; the quantitative oversupply may compensate for the qualitative defect of the dnaG2903 primase. An alternative mechanism of suppression by sdgB is discussed.

Base Sequence↗
PubMed1989

Possible mechanisms involved in growth hormone secretion induced by galanin in the rat.

The mechanisms by which central or systemic administration of galanin stimulates GH secretion were investigated in either conscious or urethane-anesthetized male rats. Intracerebroventricular injection of synthetic porcine galanin, a 29-amino acid gut-brain peptide (0.12, 0.6, and 3 nmol/rat), resulted in a dose-related increase in plasma GH. The plasma GH level was increased by an N-terminal galanin fragment [galanin-(1-19)], but not by C-terminal fragments [galanin-(2-29) and -(21-29)]. Intravenous injection or infusion of galanin (0.6 and 3 nmol/100 g BW) also raised plasma GH. The plasma GH increase induced by galanin was inhibited by pretreatment with rabbit antiserum specific for rat GRF. Pretreatment with yohimbine or phenoxybenzamine, alpha-adrenergic blockers, or picrotoxin, a gamma-aminobutyric acid (GABA) antagonist, blunted the plasma GH increase induced by intracerebroventricular injection of galanin. On the other hand, the plasma GH increase induced by iv injection of galanin was suppressed by picrotoxin, but not by phenoxybenzamine. These findings suggest that 1) both central and systemic administration of galanin stimulate GH secretion in the rat; 2) the N-terminal structure of galanin is required to stimulate GH secretion; 3) the stimulating effect of galanin is mediated, at least in part, by hypothalamic GRF; and 4) central alpha-adrenergic and GABAergic mechanisms may be involved in GH release induced by central administration of galanin, whereas systemic injection of galanin stimulates GH release predominantly through GABAergic mechanisms in the rat.

Adrenergic alpha-Antagonists↗
PubMed1989

Improvement of right ventricular systolic performance by long-term domiciliary oxygen therapy in patients with chronic respiratory failure.

Eight patients with clinically stable chronic respiratory failure, hypoxemia (PaO2 less than or equal to 60 mmHg) and pulmonary hypertension (mean pulmonary arterial pressure greater than or equal to 20 mmHg) were allocated to long-term domiciliary oxygen therapy, and were followed for three months. Oxygen was supplied for from 15 to 18 hours daily from an oxygen concentrator at a flow rate sufficient to raise the PaO2 to 60 to 80 mmHg. We examined the effects of this therapy on right ventricular performance both at rest and during exercise in these patients. Hemodynamic data were obtained by right heart catheterization. Right ventricular ejection fractions (RVEF) were ascertained using first-pass quantitative radionuclide 81mKr angiocardiography. Thirty minutes of oxygen inhalation at rest had no significant effect on cardiac function, both before therapy (T0) and after 3 months of therapy (T1). The mean pulmonary arterial pressure and the pulmonary vascular resistance during exercise were not significantly different between T0 and T1. On the other hand, at T0, the RVEF tended to decrease from 51.6 +/- 4.9% (during oxygen inhalation at rest) to 48.7 +/- 7.9% (during exercise), whereas at T1 it significantly (p less than 0.05) increased from 48.8 +/- 6.8% (during oxygen inhalation at rest) to 54.2 +/- 8.2% (during exercise). Thus, while 3 months of long-term domiciliary oxygen therapy did not reduce the right ventricular afterload either at rest or during exercise, it was found to improve the right ventricular systolic performance during exercise. This suggested that long-term oxygen therapy could be useful in improving the quality of daily life of patients with chronic respiratory failure.

Aged↗
PubMed1989

Study of cardiac hypertrophy--humoral factors that stimulate protein metabolism of cultured rat heart cells.

Recent extensive studies suggested that some humoral factors may contribute to the development and/or reversal of cardiac hypertrophy in hypertension. The purpose of this study is to examine whether there exists humoral factor(s) for cardiac hypertrophy in experimental perinephritic hypertension in dogs. Hypertension was induced by the method of Page with some modifications. Humoral factors were studied using a microassay system that was independent of pressure overload, hemodynamic effects, and other factors. L(-)-isoproterenol (ISO) and angiotensin II (AngII) increased the uptake of 3H-uridine into 10-day-old cultured heart cells. The maximal response to ISO or AngII was obtained by 10(-5) M ISO or 10(-10) M AngII, and the percent increments in the uptake of 3H-uridine was 38.4 +/- 20.4%, and 45.1 +/- 22.5%, respectively. Moreover, ISO, DL-noradrenaline, and AngII stimulated protein synthesis of 7-day-old or 14-day-old cultured heart cells in this order (9.5 +/- 1.5, 7.3 +/- 1.2, 2.0 +/- 0.5 micrograms/6 x 10(5) by 7-day-old heart cells; 23.8 +/- 8.3, 19.0 +/- 9.4, 4.4 +/- 1.1 micrograms/6 x 10(5) by 14-day-old heart cells). Heart and kidney extracts were obtained from experimental perinephritic hypertensive dogs and sham-operated dogs. The heart extract obtained from hypertrophied left ventricle (LV) of the experimental hypertensive dogs, but not of the sham-operated dogs, increased the uptake of 3H-uridine into 10-day-old heart cells. The mean percent increment in uptake of 3H-uridine induced by the hypertrophied LV heart extract at a final concentration of 5 x 10(-3)% V/V (1-3 micrograms) in different experiments was about 15%. High performance liquid chromatography (HPLC) demonstrated that the LV heart extract obtained from the perinephritic hypertensive dogs contained at least 16 molecules. Among them, one with a molecular weight of approximately 11,200 daltons stimulated uptake of both 3H-uridine and 14C-leucine into cultured heart cells. These results demonstrated that heart extract obtained from hypertrophied LV of perinephritic hypertensive dogs contained at least one factor which may induce and/or modulate myocardial hypertrophy in this model for hypertension.

Angiotensin II↗
PubMed1989

Enzyme immunoassay for oxytocin.

A competitive, double antibody enzyme immunoassay for oxytocin in a heterologous system was developed. Horseradish peroxidase was conjugated with oxytocin using N-succinimidyl 3-(2-pyridyldithio) propionate, and rabbit anti-oxytocin serum was produced by immunization of oxytocin-bovine serum albumin complex which was prepared by the carbodiimide method. The sensitivity of the assay was 4 microIU/tube, which corresponded to 10 microIU per ml using 400 microliters of the sample which was extracted from the same volume of plasma by means of SEP-PAK C18 cartridges. The coefficients of variation for different levels of oxytocin ranged from 6.8-15.9% and 8.5-16.7%, for intra- and inter-assay. Recovery of oxytocin added to plasma after extraction was 99-117%. No or little cross-reaction with arginine- and lysine-vasopressin was found. Plasma oxytocin concentrations determined by the proposed enzyme immunoassay were well correlated with those determined by radioimmunoassay (r = 0.90).

Immunoenzyme Techniques↗
PubMed1989

Measurement of nocturnal urinary growth hormone values.

Nocturnal urinary growth hormone values were measured by a sensitive enzyme immunoassay in normal adults, patients with GH deficiency, patients with Turner's syndrome, normal but short children who had normal plasma GH responses to provocative tests, and patients with acromegaly. The mean nocturnal urinary GH values in patients with acromegaly were significantly greater than those in normal adults (1582.3 +/- 579.8 vs 53.5 +/- 8.6 pmol/mmol creatinine (+/- SEM); p less than 0.05). In the normal but short children and patients with Turner's syndrome, the mean nocturnal urinary GH values were 83.1 +/- 5.2 and 79.8 +/- 29.5 pmol/mmol creatinine, respectively. In patients with GH deficiency, the nocturnal urinary GH values were undetectable (less than 5.3 pmol/mmol creatinine) except in one patient where the value was 6.3 pmol/mmol creatinine. The nocturnal urinary GH values of the patients with GH deficiency were significantly lower than those of the other groups (p less than 0.05). In normal but short children, the nocturnal urinary GH values correlated significantly with mean plasma nocturnal GH concentrations (r = 0.76, p less than 0.001), and 24-hour urinary GH values (r = 0.84, p less than 0.001), respectively. In 4 patients with GH deficiency who had circulating anti-hGH antibody, the urinary GH values were also undetectable. These data indicate that nocturnal urinary GH value reflects endogenous GH secretion during collection time, and that measurement of the nocturnal urinary GH values is a useful method for screening of patients with GH deficiency and acromegaly.

Acromegaly↗
PubMed1989

A highly sensitive sandwich enzyme immunoassay of urinary growth hormone in children with short stature, Turner's syndrome, and simple obesity.

GH values were determined by a highly sensitive sandwich enzyme immunoassay in the 1st morning and/or 24-h accumulated urine samples in 94 children (short stature 70, including 14 with complete GH deficiency, 9 with partial GH deficiency, and 47 with GH-normal short stature; Turner's syndrome, 10, and simple obesity, 14). GH values were also determined in the 2nd to 4th urine samples taken on the same day together with the 1st morning urine in 5 of them. GH values in the 1st morning urine correlated significantly with those of the 24-h urine and with serum peak and mean GH values during nocturnal sleep as a physiological GH secretion test. The 2nd to 4th urines had lower GH concentrations than the 1st morning urine. The GH value of the 1st morning urine in complete GH deficiency was significantly lower than those in GH-normal short stature, partial GH deficiency and Turner's syndrome. However, no significant difference was detected in urinary GH values between complete GH deficiency and simple obesity. We conclude that 1st morning urinary GH estimation may be useful for differentiation of complete GH deficiency from other causes of short stature, but may be difficult for the distinction between complete GH-deficiency and obesity with normal GH secretory ability.

Adolescent↗
PubMed1989

Effect of alpha 2-adrenergic receptor antagonist (midaglizole) on gastrointestinal motility in conscious dogs.

To clarify the physiological role of the mechanism that adrenergic nerve inhibits Ach release from intramural cholinergic nerve endings, the influence of Midaglizole, alpha 2-adrenergic receptor antagonist, to postprandial gastrointestinal motilities in conscious dogs was investigated. Postprandial motilities of gastric antrum, duodenum, ileum, and colon were significantly enhanced by Midaglizole (3.0-5.0 mg/kg body weight, i.v.). These excitatory responses were abolished by atropine (0.05-0.1 mg/kg body weight, i.v.). On the other hand, in most cases (29 cases out of 32), when Midaglizole was administered during quiesent phase of IMC, no change occurred in gastrointestinal motility. However, after subliminal dose of pentagastrin or cisapride, which stimulated Ach release from intramural cholinergic neuron without development of motility, was administered, Midaglizole induced phasic, postprandial motility-like contraction in gastrointestinal tract. Even in the fasted state, when Midaglizole was administered intragastrically, irregular contractions with high amplitude occurred in every regions from gastric antrum to colon. And these excitatory responses were abolished by atropine. Similar reaction was observed also in truncal vagotomized dogs. These results suggest that it is the physiological mechanism that adrenergic nerve presynaptically inhibits Ach release from intramural cholinergic neuron, which is the main mechanism of development of postprandial motility, acting on alpha 2-adrenergic receptor, and has tonic control of postprandial motility.

Adrenergic alpha-Antagonists↗
PubMed1989

Possible involvement of endogenous opioid peptides in prolactin secretion induced by alpha 2-adrenergic stimulation in rats.

Noradrenergic mechanisms have a stimulatory role in regulating prolactin (PRL) secretion in the rat. We investigated the mechanism by which the alpha 2-adrenergic system stimulates PRL release in urethane-anesthetized male rats. Intracerebroventricular injection of norepinephrine (2 micrograms/rat) or epinephrine (100 ng and 1 microgram/rat) caused an increase in plasma PRL levels. The PRL increase induced by epinephrine was much greater than that by norepinephrine. Intracerebroventricular injection of phentolamine (1 microgram/rat), an alpha-antagonist, blunted the plasma PRL increase induced by epinephrine (100 ng intracerebroventricularly). Plasma PRL levels were increased by intravenous injection of alpha 2-agonists, clonidine (15 micrograms/100 g of body wt), and xylazine (200 micrograms/100 g of body wt). Plasma PRL increase induced by clonidine or xylazine was suppressed by intravenous injection of naloxone (125 micrograms/100 g of body wt), an opiate antagonist. These findings suggest that alpha 2-adrenergic mechanisms stimulate pituitary PRL secretion, at least partly, by activating endogenous opioid peptides in the rat.

Animals↗
PubMed1989

[Nuclear DNA cytofluorometry of normal human laryngeal epithelia and squamous cell carcinoma].

Normal human laryngeal epithelia and laryngeal squamous cell carcinoma were assayed by Feulgen DNA cytofluorometry using free cell nuclei isolated from carnoy-fixed, paraffin-embedded specimens. In all of the 12 normal specimens, the epithelium showed typical diploid cell clones with low proliferative activity. Polyploid cells were seen in only two specimens from subjects aged 61 and 69 years respectively, and the number of polyploid cells seen in these two specimens was only two. Fifteen cancer cases were divided into three groups: an untreated group (5 cases), a chemotherapy group (5 cases) and a group of cases with recurrence after radiation therapy (5 cases). Among these three groups the DNA ploidy patterns were compared. In the untreated group, all cases showed a two-peak diploid pattern and a high proliferative activity, and polyploid cells were present. In the chemotherapy group, a wide one-peak histogram extending from 2C to about 5C was noted in 4 cases, and an aneuploid pattern in one case. Thus, the DNA ploidy pattern in the chemotherapy group differed from that in the untreated group. Of the 5 cases with recurrence after radiation therapy, one had a tetraploid pattern, but the remaining 4, a two-peak diploid pattern similar to that seen in the untreated group. Polyploid cells were observed in all these cancer cases. However, because they were also seen in some normal subjects, the finding of polyploid cells is not considered to be conclusive of cancer diagnosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1989

[Audiological study for ears with aural stenosis and atresia].

The audiological study for ears with aural stenosis and atresia was performed. The hearing level of ears with three types of ear plugs (with the hole of phi 1mm, with the hole of phi 3mm and without the hole) was tested experimentally by 10 normal hearing subjects in pure tone audiometry, and the audiograms of congenital and acquired aural stenosis and atresia were investigated statistically. And then following results were obtained. 1) The air conduction levels were higher, as the diameter of ear plug's hole got shorter in normal hearing subjects. And the shape of their audiograms was gradual sloping type. 2) The air conduction levels of ears with congenital aural stenosis and atresia were almost from 60 to 70 dB, and the levels were almost same throughout 7 frequencies. But the audiograms of ears with acquired aural stenosis and atresia showed conductive and gradual sloping type. 3) From the results mentioned above, the reason why the hearing loss of ears with aural stenosis and atresia showed conductive hearing loss limited to low and middle frequencies was considered to depend on the abnormality of the middle ear. 4) An average value of hearing threshold level in bone conduction among normal hearing subjects with three types of ear plugs was almost -7.8dB. There was no relation between the size of ear plug's hole and the shift of bone conduction level.

Adult↗
PubMed1989

[Bacteriological investigation of the pre- and postoperative transition of the pharyngeal flora in the patients received tonsillectomy].

Several investigations have been reported on the interactive relation between the normal flora and the pathogenic micro-organisms in the human upper respiratory tracts (Thompson, Sanders, etc). It has also been known that some alpha-streptococci have inhibitory effect on the growth of group A beta-hemolytic streptococci. A study upon the role of alpha-streptococci in the throat (tonsil and pharynx) was performed using 73 culture specimens (throat swabs) obtained from 42 patients. Forty-four specimens were taken from the patients who received tonsillectomy, pre- and postoperatively, and 29 were from the patients who did not receive the operation. In the group of patients who received tonsillectomy, alpha-streptococci with inhibitory effect on the growth of group A beta-streptococci were detected less frequently preoperatively, when compared with the patients without tonsillectomy. On the other hand, postoperatively, marked increase of alpha-streptococci of these types was found in the normal flora of the throat. However, further detailed study on this subject is necessary because of the exceptional results in our observations.

Adolescent↗
PubMed1989

Recombinant interferon-gamma is a potent inhibitor of osteoblastic cell functions.

Interleukin-1 and tumor necrosis factor-stimulated bone resorption is mediated by osteoclast-activating factor elaborated by osteoblasts. Recombinant interferon-gamma inhibits stimulation of bone resorption by these cytokines. We examined here the effects of recombinant mouse interferon-gamma (rmIFN-G) on DNA and collagen synthesis, and on alkaline phosphatase (ALP) activity, in the osteoblastic cell line (MC3T3-E1) under confluent culture conditions. Addition of rmIFN-G to the cells markedly inhibited their DNA synthesis and ALP activity in dose- and culture time-related manner. Also we found that rmIFN-G decreased markedly collagen synthesis at day 3 after addition of the agent. These data indicate that rmIFN-G is a potent inhibitor of osteoblastic cell functions.

Alkaline Phosphatase↗
PubMed1989

[Syrinx-like artifact on MR images of the spinal cord].

We evaluated the syrinx like artifact on midline sagittal MR images of cervical spine. This artifact appeared as linear regions of low intensity along the length of the spinal cord. This artifact was frequently seen. And, when it appear as a single midline band, it mimics pathological conditions such as a syrinx. We found that this artifact eliminated by increasing the number of phase encoding steps, or decreasing the field of view. These method were useful for differentiation of artifact from syrinx.

Cervical Vertebrae↗