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Biomedical subjects

M Chiba

Publications and source records attributed to M Chiba.

At least 397 records · Page 22Linked to original sources
PubMed1980

Effect of tin on porphyrin biosynthesis.

Certain disturbances in porphyrin biosynthesis were examined in rabbits administered with either tin or lead. Stannous chloride treatment increased the concentrations of coproporphyrin in blood and urine, as did lead acetate treatment. No effect of tin on 5-aminolevulinic acid concentration was observed in blood and urine, whereas lead treatment increased it markedly in both. Tin profoundly inhibited the activity of 5-aminolevulinate dehydratase in blood, but did not alter it in liver although tin content in liver was considerably higher than that in blood. In contrast to a prolonged inhibition of erythrocyte 5-aminolevulinate dehydratase by lead, tin inhibition of erythrocyte 5-aminolevulinate dehydratase activity was rapidly reversed after the cessation of the metal treatment.

Aminolevulinic Acid↗
PubMed1980

Isolation and characterization of colonic intraepithelial and lamina proprial lymphocytes.

A technique is described, involving sequential treatment of the human colonic mucosa with EDTA in calcium-magnesium-free medium, and with collagenase, to isolate lymphoid cells enriched for intraepithelial (IEL) or lamina proprial lymphocytes (LPL). The IEL and LPL isolates also contained small numbers of eosinophils, mast cells, neutrophils, and macrophages. Plasma cells were present in the LPL but not in the IEL. The IEL isolates contained approximately equal proportions of T, B, and null cells. In contrast, the LPL suspensions contained 52% of T cells, 22% of B cells, and 26% of null cells. The most prevalent membrane immunoglobulin in the two colonic lymphoid cell suspensions was IgA (IEL--53%; LPL--71%). In colonic tissue sections, the percentages of immunoglobulin-containing cells as well as the proportions of cells containing IgA, both in the epithelial layer and the lamina propria, were similar to those found in the suspensions of lymphocytes stained for membrane immunoglobulin. These and other morphologic and characterization data support the contention that the two colonic lymphoid cell populations, obtained by the isolation procedures, were selectively enriched for intraepithelial or lamina proprial lymphocytes, respectively. Thus, this technique provides an important tool for further studies of the functional properties of the gut-associated lymphoid tissues.

Basement Membrane↗
PubMed1980

Patterns of organization of comments on the corticopontine projection in the cat with the pontocerebellar projection.

Following lesions of various parts of the cat cerebral cortex, the distribution of degenerating fibers in the pontine nuclei was mapped in drawings of serial transverse and horizontal sections of Fink and Heimer. All parts of the cerebrum give rise to the corticopontine fibers and each functionally uniform area has its particular projection zones in the pons. Thus, it has been shown that the pontine projection zones from the sensorimotor, auditory, orbital, cingulate and "association" cortices are arranged in longitudinal columns throughout the pons, mostly in well delimited columns, while those from the visual cortex reveal columns oriented transversely in the rostral part of the pons. When the distribution of the pontine afferents from various parts of the cortex are compared in detail, it is evident that there are differences in locations of the columns, clustered in continuous zones of terminations, among different pontine projections, although there are partial overlaps among these projection zones. The present as well as the previous findings of the corticopontine projection are correlated with observations of the pontocerebellar projection obtained by other investigators with the horseradish peroxidase and the autoradiographic methods, and a possible propagation of different modalities of sensations from the cerebral cortex, via the pons, to the cerebellum is discussed with reference to some physiological data. The present study largely confirms and extends the previous data of the corticopontine projection and reveals that the cortico-ponto-cerebellar pathways are more cmplexly organized than was previously assumed.

Afferent Pathways↗
PubMed1980

High performance liquid chromatographic method for simultaneous determination of residual benomyl and methyl 2-benzimidazole carbamate on apple foliage without cleanup.

A simple HPLC method has been developed to individually determine residues of benomyl and MBC on apple leaves without cleanup. Sample leaves in a Mason jar are freeze-dried and tumbled for extraction in CHCl3 containing 5000 microgram n-propyl isocyanate/mL at 1 degree C. n-Butyl isocyanate is added to the extract of 5000 microgram/mL, and 20 microL of the mixture is injected into the HPLC system. A brownlee LiChrosorb silica gel column with a guard column is operated with a mixed mobile phase of chloroform--hexane (4 + 1) saturated with water. MBC, present as a degradation compound of benomyl, is identified as methyl 1 - (n - propylcarbamoyl) - 2 - benzimidazole carbamate (MBC-n-PIC derivative). At 280 nm, both benomyl and MBC-n-PIC can be detected with a UV detector at a level of 0.2 ppm in apple leaves.

Benomyl↗
PubMed1979

Cortical neurons projecting to the pontine nuclei in the cat. An experimental study with the horseradish peroxidase technique.

Horseradish peroxidase (HRP) injections in various portions of the cat pontine nuclei resulted in retrograde labeling of neurons in layer V of the ipsilateral cerebral cortex. Corticopontine neurons, pyramidal in type, have been found to be labeled in the entire cortex, confirming the previous findings of anterograde degeneration studies. Most (91%) of the labeled cells were 14--26 micrometer in diameter (mean 19.4 +/- 4.5 micrometer SD). Small (10--20 micrometer) and medium (20--40 micrometer) cells represent 51.5% and 47.7%, respectively, of the total number of the labeled neurons. The populations of the neurons of various sizes were almost identical in different cortical areas, and were different from the populations of corticoreticular and corticospinal cells. Corticopontine cells were well labeled in experimental cases of 3-days' survival time, confirming the topographical organization established previously by degeneration studies for this projection system. However, in cases of shorter survival time (20--27 h), the number of labeled neurons was very small. The relative paucity of labeled corticopontine neurons in the sigmoid and lateral gyri is discussed with reference to other cortical descending neurons (e.g., the corticotectal, corticoreticular and corticospinal) which have hitherto been identified morphologically as well as physiologically.

Animals↗
PubMed1979

K-Cell activity in lamina proprial lymphocytes from the human colon.

Using an enzymatic method for their isolation, it has been shown that human colonic lamina proprial lymphocytes, isolated from patients with various colonic diseases and depleted of polymorphonuclear leukocytes and macrophages, demonstrated K-cell activity in two antibody-dependent cell-mediated cytotoxicity assays in vitro. No differences were found between the activities of lamina proprial lymphocytes isolated from colonic specimens involved by Crohn's disease, chronic ulcerative colitis, or colonorectal carcinoma. K-cell activity was demonstrable using lymphoid cells isolated from the colons of patients receiving steroid therapy at the time of the therapeutic resections. These findings indicate the need for further investigation of possible roles for K-cells in local immune responses in the human bowel mucosa in inflammatory and neoplastic diseases.

B-Lymphocytes↗
PubMed1979

5-aminolevulinate dehydratase activity in blood of rabbits given tin or lead.

The activity of 5-aminolevulinate dehydratase (ALAD) in rabbit blood is significantly inhibited by tin. Intravenous administration of tin (0.48 or 4.8 mumol/kg body weight) causes a decrease in the activity of the enzyme by 60% or 94% respectively. The effects of tin and lead on ALAD differ: inhibition by tin is not affected by pre-incubation at 50-60 degrees C, whereas the inhibitory effect of lead is increased by the same pretreatment. The optimum pH for rabbit blood ALAD is 6.8 in control rabbits. This optimum shifts to pH 5.8-6.0 in the blood of tin-treated rabbits, with or without pre-incubation at 60 degrees C for 5 min, while a similar shift is prevented by the same pre-incubation after lead treatment. Recovery to normal activity is faster after tin than after lead treatment.

Animals↗