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Biomedical subjects

K Kitano

Publications and source records attributed to K Kitano.

At least 181 records · Page 10Linked to original sources
PubMed1981

Sulfazecin and isosulfazecin, novel beta-lactam antibiotics of bacterial origin.

In the long history of screening for antibiotics, fungi and actinomycetes have been the only producers of beta-lactam antibiotics although several phytopathogenic bacteria have been reported to produce toxins with a beta-lactam structure. We report here the first evidence that novel monocyclic beta-lactam antibiotics, sulfazecin and isosulfazecin, are produced by new species of Pseudomonas.

Anti-Bacterial Agents↗
PubMed1981

Electrophysiologic and histologic correlations in chronic complete atrioventricular block.

Electrophysiologic studies using the His bundle electrogram (HBE) and histologic studies of serial sections of the conduction system were correlated in two groups of deceased patients. Group 1 consisted of five patients with chronic complete atrioventricular block (CAVB) who had narrow QRS complexes and AH block (block proximal to the His bundle deflection). Group 2 consisted of four patients with chronic CAVB who had wide QRS complexes and HV block (block distal to the His bundle deflection). In group 1, the sites of the main lesion were not located in the approaches to the atrioventricular (AV) node or the AV node, but were found in the penetrating portion of the His bundle in one patient and in the branching portion of the His bundle in three patients. In the remaining patient, the main site of block could not be demonstrated histologically in the AV conduction system, but marked fibrosis of the approaches to the sinoatrial node and surrounding atrial muscle was found. In all patients of group 2, the site of the main lesion was located in the bilateral bundle branches, and thus was compatible with so-called trifascicular block. This correlation study between the His bundle electrogram and histologic findings of the AV conduction system showed that in some cases, CAVB presenting as AH block on the HBE can be associated with a lesion in the branching portion of the His bundle (distal His), and that CAVB presenting as HV block on the HBE is associated with a bilateral lesion of the bundle branches.

Aged↗
PubMed1980

C-19393 S2 and H2, new carbapenem antibiotics. I. Taxonomy of the producing strain, fermentation and antibacterial properties.

C-19393 S2 and H2 are new carbapenem antibiotics produced by a streptomycete. The producing strain was taxonomically studied and named Streptomyces griseus subsp. cryophilus. Cobaltous compounds were necessary for production of the antibiotics. C-19393 S2 and H2 showed a broad spectrum of antibacterial activities with C-19393 H2 being 8 approximately 120 times more active than C-19393 S2. They also exhibited beta-lactamase-inhibiting activities and acted synergistically with ampicillin and cefotiam against clinical isolates resistant to beta-lactam antibiotics.

Anti-Bacterial Agents↗
PubMed1980

Possible factors influencing the immunoglobulin G concentration in swine colostrum.

The immunoglobulin (Ig) G concentration in swine colostrum was determined by the single radial immunodiffusion method, using 157 samples collected from farm-raised sows in the Yamaguchi Prefecture of Japan during 1976 and 1977. The mean IgG value was 53.03 mg/ml, and the maximum and minimum values were 101.39 mg/ml and 11.74 mg/ml, respectively. The amount of IgG varied greatly among sows. To clarify the possible factors influencing the amount of IgG in colostrum, the following items were surveyed: season, district, breed, age of sows, number of parturitions, udder section from which samples were collected, kind of feed, vaccinations of swine erysipelas live-organism vaccine, hog cholera live-virus vaccine, Japanese encephalitis live-virus vaccine, tramsmissible gastroenteritis liver-virus vaccine, type of farming, and number of sows raised on a farm. Relationships between the amount of IgG in colostrum and each of these 13 items were analyzed. Seemingly, strong correlations with the amounts if IgG in colostrum were found with five items (district, number of parturitions, kind of feed, type of farming, and number of sows). To the contrary, five items (age, udder section, and vaccinations of swine erysipelas live-organism vaccine, hog cholera live-virus vaccine, and Japanese encephalitis live-virus vaccine) had poor correlations. Other items had moderate correlations. The multiple correlation coefficient obtained was 0.5499.

Age Factors↗
PubMed1980

Antibacterial antibodies in swine colostrum.

Antibacterial antibody activities were examined in 138 samples of swine colostrum by O-agglutinin test with serotypes of Escherichia coli (O-6, 0-45, 0-81, 0-83, 0-115, 0-138, O-139, and O-126), Salmonella typhimurium, and Salmonella cholerae suis. The mean agglutinin titer of E coli O-83 was the highest; E coli O-115 was next highest. The mean agglutinin titer of S cholerae suis was lowest; S typhimurium was next to lowest. Correlation coefficients among these O-agglutinin titers were between 0.109 and 0.693. Correlations of S typhimurium were the poorest; those of E coli O83, E coli O-138, and S cholerae suis were also poor. By principal component analysis, it was possible to classify ten kinds of O-agglutinins into four groups. The cumulative proportion of the first four principal components accounted for 77.97% of the total variance. Cumulative coefficients of factor loadings were from 65.25% to 99.50% of these O-agglutinins.

Agglutinins↗
PubMed1979

Triggering of autolytic cell wall degradation in Escherichia coli by beta-lactam antibiotics.

A biochemical method was developed to quantitatively compare the effectiveness of beta-lactams in triggering murein degradation (autolysin activity) in Escherichia coli. Bacteria prelabeled in their cell walls with radioactive diaminopimelic acid in growth medium were exposed for 10 min to the antibiotics at the appropriate minimal growth inhibitory concentrations and at multiples of these values, and the rate of cell wall degradation was followed during subsequent penicillin-binding protein (PBP)-1 were the most effective triggers of autolytic wall degradation; beta-lactams selective for PBP-2 were the poorest; and antibiotics preferentially binding to PBP-3 showed intermediate activities. The relative effectiveness of beta-lactams in autolysin triggering was found to parallel the effectiveness of the same drugs in causing rapid loss of viability, culture lysis, and spheroplast formation. Autolysin triggering was suppressed by inhibitors of protein and ribonucleic acid biosynthesis but not by inhibitors of deoxyribonucleic acid synthesis. The beta-lactam-induced cell wall degradation did not seem to involve a direct stimulation of enzyme activity or synthesis of new enzyme molecules, and murein sacculi isolated from cells that had been preexposed to a triggering dose of beta-lactam treatment exhibited the same sensitivity to crude, homologous autolysins as sacculi prepared from untreated control bacteria. On the basis of these observations, mechanisms are considered for the triggering of E. coli autolysins and for the role of autolytic activity in bacterial spheroplast formation, lysis, and death.

Anti-Bacterial Agents↗
PubMed1979

Escherichia coli mutants tolerant to beta-lactam antibiotics.

Two types of Escherichia coli mutants tolerant to beta-lactam antibiotics were isolated. One is E. coli chi2452, which showed a tolerant response against beta-lactam antibiotics when grown at 42 degrees C, and the others are the mutants C-80 and C-254, selected from mutagenized E. coli chi1776 by cycles of exposure to ampicillin, cephaloridine, and starvation of the nutritionally required diaminopimelic acid. Beta-lactam antibiotics caused rapid loss of viability and lysis in cultures of chi1776 or in chi2452 grown at 32 degrees C. In contrast, the same antibiotics caused only a reversible inhibition of growth in mutants C-80 and C-254 or in cultures of chi2452 grown at 42 degrees C. Beta-lactam antibiotics that show high affinity for penicillin-binding proteins 2 or 3 (mecillinam and cephalexin, respectively) induced similar morphological effects (ovoid cell formation and filament formation) in both parent and mutant strains. In contrast, beta-lactam antibiotics which have a high affinity for penicillin-binding protein 1 (e.g., cephaloridine or cefoxitin), which cause rapid lysis in the parental strains, caused cell elongation in the tolerant bacteria. In contrast to the parental cells, autolytic cell wall degradation was not triggered by beta-lactam treatment of chi2452 cells grown at 42 degrees C or in mutants C-80 and C-254. The total autolytic activity of mutants C-80 and C-254 was less than 30% that of the parent strain. However, virtually identical autolytic activities were found in cells of chi2452 grown either at 42 or 32 degrees C. Possible mechanisms for the penicillin tolerance of E. coli are considered on the basis of these findings.

Ampicillin↗
PubMed1977

Raphe induced inhibition of intralaminar thalamic unitary activities and its blockade by para-chlorophenylalanine in cats.

Extracellular recordings were made of intralaminar thalamic neurones responding to stimulation of the radial nerves. The effects on this response of a conditioning stimulation of the median raphe nucleus were studied in both untreated and p-CPA pretreated cats. Ninety-two percent of thalamic responses to somatic stimulation in untreated cats was inhibited by conditioning stimulation of the raphe nucleus. The intensities of conditioning stimulation required for the inhibition were significantly higher in cats pretreated with p-CPA than in cats not treated with the drug. It is suggested that raphe projection to intralaminar thalamus excerts an inhibitory influence on thalamic activities, and that the inhibition is mediated by a putative neurotransmitter, serotonin. The possible involvement of the median raphe nucleus in pain processing is discussed.

Animals↗
PubMed1977

Clinical and electrophysiologic studies on the Wolff-Parkinson-White syndrome in aged cases.

Clinical and electrophysiologic studies were performed in 10 aged cases (50-82 years of age) with WPW syndrome and following results were obtained: 1) Episodes of paroxysm of supraventricular tachyarrhythmias were observed in 7 and complication of sinus node dysfunction was noted in 3. 2) P-delta intervals on electrocardiogram exceeding 0.12 sec were observed in 4 cases. 3) Patterns of normalization of QRS complex in 4 cases were characterized by tachycardia-dependent in 2 and bradycardia-dependent in 2. 4) Effective refractory period of the accessory pathway (AP) in antegrade direction exceeded that of A-V node in 5 cases and the former exceeding 500 msec was observed in 2 cases. The relations between the changes of the electrophysiologic properties of the AP and altered clinical manifestations of the WPW syndrome in aged cases were discussed.

Age Factors↗
PubMed1977

[Familial multiple hemangioblastomas--report of two cases in a family (author's transl)].

The authors reported their experience with two cases in a kindred with multiple hemangioblastomas in the cerebellum, brain stem, and spinal cord associated with von Hippel's disease, von Recklinghausen's disease and some visceral changes. (The members of this kindred died of similar disease.) Two patients, a 42-year-old man and his 14-year-old niece, showed various neurological signs involving central nervous system. Furthermore the man had some café-au-lait spots in the skin, a papillomatous tumors in the tongue and a vascular tumor in the right kidney. Both also had von Hippel's disease. Neuroradiological study and operations demonstrated multiple hemangioblastomas in the cerebellum, medulla oblongata and the spinal cord in association with abnormal enlargements of the medulla and the spinal cord which suggested coexistence of the parenchymatous tumor, probably glioma, in them. All hemangioblastomas in the cerebellum of both patients were removed. The literature of the familial multiple hemangioblastomas was reviewed and the coexistence of Lindau's disease, von Recklinghausen's disease and glioma was discussed.

Adolescent↗