PubMed Health⌕ Search

Biomedical subjects

K Honma

Publications and source records attributed to K Honma.

At least 235 records · Page 13Linked to original sources
PubMed1982

Hepatic alveolar echinococcosis invading pancreas, vertebrae, and spinal cord.

A case of hepatic alveolor echinococcosis with contiguous invasion of the pancreas, vertebrae, and spinal cord and intrathecal metastases to the brain stem is reported. The long course after a hemihepatectomy may be a factor in the modification of the natural course of the disease and in the induction of this unusual mode of spread.

Adult↗
PubMed1982

Ontogeny of the circadian rhythm of plasma corticosterone in blind infantile rats.

1. Post-natal manifestation of plasma corticosterone rhythm was followed by individual pups until the end of 12 weeks of life. Results obtained were analysed by both visual inspection and a least squares spectrum method. The validity of the approaches used was evaluated. 2. Circadian rhythm of plasma corticosterone in sighted pups under light-dark cycle (LD) first appeared at around the third post-natal week, accompanied often with a bimodal pattern: a second peak being counterphased to the first main peak. The second peak became obscure at the fourth week, disappearing as pups matured. 3. The hormone rhythm in blinded pups whose eyes were removed within 16 h of birth was free-running under LD with a period of 24.40 +/- 0.02 h (mean +/- S.E.M.). The free-running period was stable until at least the end of the twelfth week of life. 4. The acrophase of the circadian rhythm in blind pups born and reared under LD was 180 degrees out of phase to that born and reared under DL, a reversed light-dark condition. In each case, the acrophase shifted about 8 h from that of sighted pups at the fourth week of life. 5. It is suggested that an underlying oscillator for the hormone rhythm starts to oscillate earlier than the fourth week of life and the environmental light-dark cycle prior to the fourth week determines the phase angle of the circadian rhythm in blind pups.

Aging↗
PubMed1982

Possible zeitgebers for external entrainment of the circadian rhythm of plasma corticosterone in blind infantile rats.

1. The phase angle of circadian rhythm of plasma corticosterone in individual blind pups was followed in order to find out an effective zeitgeber(s) during the post-natal development. 2. The retinal light pathway before the opening of eyes was not essential for the entrainment of pups' rhythm to the environmental light-dark (LD) cycle. 3. In blinded pups whose eyes were enucleated on the day of birth, no evidence was obtained for effective extra-retinal pathways for photic inputs. 4. Free-running circadian hormone rhythm of blind pups was not entrained by 'social contact' with other sighted pups in the same cage. 5. Even when the duration of nursing was varied from 2 to 4 weeks, the phase angle of pups' rhythm at the fourth week was not affected. 6. In mother-pups exchange experiments in which pups born from LD mother were reared by DL mother (LD-DL pups) and conversely, pups from DL original mother were reared by LD foster mother (DL-LD pups), about one half of the pups at the fourth post-natal week of both groups exhibited phase angles belonging to their original mothers and the other half showed phase angles of their foster mothers. 7. It is suggested that blind pups may retain the phase angle of circadian rhythm of the original mother and the overt hormone rhythm may be modifiable by the foster mother during the early phase of post-natal life.

Aging↗
PubMed1982

Prenatal onset and maternal modifications of the circadian rhythm of plasma corticosterone in blind infantile rats.

1. In order to clarify the manner in which maternal nursing modifies the circadian rhythm of plasma corticosterone in blind pups, specified schedules of maternal nursing were imposed on blind pups and the hormone rhythm was followed individually. 2. Two groups of blinded pups were continuously nursed, alternately by two mother rats having different circadian phases of lactating period. In both groups, phase angles of the original mother were predominantly reflected in the phase of the pups' hormone rhythm. 3. When the maternal nursing was limited only during the light period (L nursing), it caused no detectable effect on the pups' hormone rhythm. 4. In contrast, when the maternal nursing was limited only during the dark period (D nursing), approximately one half of the pups at the fourth post-natal week showed a bimodal pattern of hormone rhythm. A second peak appearing 180 degrees out of phase to the first peak disappeared by the sixth or eight post-natal week. 5. It is concluded that the circadian oscillation underlying the plasma corticosterone rhythm starts to function prenatally and the original mother (probably, a prenatal LD cycle) primarily determines the phase angle of the circadian oscillation in blind pups. The maternal nursing does not entrain the pups' circadian oscillation, but does modify transiently the overt hormone rhythm, probably through a discord between maternal nursing and pups' feeding phases.

Animals↗
PubMed1981

Isolation and partial structural characterization of macroglycolipid from rabbit erythrocyte membranes.

A macroglycolipid containing galactose and N-acetylglucosamine as predominant sugar constituents was prepared together with glycophorin from rabbit erythrocyte membranes by extraction with lithium diiodosalicylate and partition in aqueous phenol. The macroglycolipid was effectively separated from the glycophorin fraction by ion-exchange chromatography in the presence of a detergent, Ammonyx LO. Its yield (ca. 4 mg/100 ml erythrocytes) was significantly higher than that of the macroglycolipids from human erythrocytes. The structure of the carbohydrate moiety in the macroglycolipid was analyzed by methylation analysis, Smith degradation, nitrous acid deamination, and chromium trioxide oxidation. Assuming one ceramide residue per molecule, the average number of sugars in the macroglycolipid was about 30. The macroglycolipid had a highly branching structure: Gal(alpha 1 leads to 3)Gal(beta 1 leads to 4)GlcNAc sequences are present at nonreducing termini and leads to 3 Gal(beta 1-4)GlcNAc repeating units are present in the inner core of the sugar chain. Some of the inner galactose residues branch at the C-6 position. Constituents of the ceramide moiety were also characterized.

Animals↗
PubMed1980

The role of monoamines in female puberty.

The estradiol positive feedback mechanism appears to become mature between days 10 and 20 after birth. Rising serum prolactin levels between day 20 after birth and puberty are correlated with high hypothalamic norepinephrine turnover. High prolactin levels stimulate hypothalamic dopamine (DA) turnover, which may actively inhibit hypothalamic luteinizing hormone-releasing hormone (LHRH) release. Hypothalamic DNA receptor sensitivity is high in 10- to 20-day-old rats and gradually decreases between day 20 after birth and puberty. The reason for this desensitization may be the high hypothalamic DA turnover. This may result in a less strong inhibition of LHRH release allowing the positive feedback action of estradiol to elicit the first preovulatory luteinizing hormone (LH) surge initiating puberty.

Adrenalectomy↗
PubMed1980

Amino acid sequence and attachment sites of oligosaccharide units of porcine erythrocyte glycophorin.

The amino acid sequence of the glycophorin from porcine erythrocyte membrane has been determined by Edman degradation. Porcine glycophorin is a polypeptide chain of 133 amino acid residues and contains 12 oligosaccharide units attached to the amino-terminal side of the molecule. Ten oligosaccharides are linked O-glycosidically to threonine/serine residues and the remaining two oligosaccharides are attached N-glycosidically to asparagine residues. The amino acid sequence is consistent with the transmembrane orientation of glycophorin. Porcine and human glycophorins are similar in amphiphilic property, molecular size, and carbohydrate content, but the two glycophorins differ considerably in the amino acid sequence: particularly, the amino-terminal sequences which are highly glycosylated show no homology.

Amino Acid Sequence↗
PubMed1979

Involvement of catecholamines in eliciting LH peaks in 15-day-old female rats: effects of treatment with prolactin.

In the serum of 15-day-old female rats, treated either with alpha-methyl-p-tyrosine (alpha-MPT) or saline, serum LH levels were determined. From the brains of all animals the medial preoptic areas (MPO) and the anterior and posterior mediobasal hypothalami (AMBH and PMBH) were punched out and stored frozen in perchloric acid. In the punches of those animals with very high or basal LH levels catecholamine concentrations were measured radioenzymatically and on the basis of the degree of catecholamine depletion after alpha-MPT the turnover rates of dopamine (DA) and norepinephrine (NE) were calculated. NE turnover in the MPO was significantly higher in the animals with high LH levels as compared to those with low LH values. In the PMBH an inverse correlation between LH levels and NE turnover rates could be demonstrated. NE turnover in the AMBH, and DA turnover in all 3 structures did not correlate with serum LH levels. Serum FSH and prolactin levels were higher in the animals with high LH levels. These changes are similar to those observed in adult proestrous rats and it is concluded that the LH peaks in 15-day-old animals reflect a positive feedback action of estradiol. In a second experiment prolactin was administered to determine if it could prevent the occurrence of these LH peaks. Ovine prolactin (2 X 0.5 micrograms/g body weight) injected from day 8--15 suppressed serum LH levels to almost undetectable values. Catecholamine turnover measurements in these animals revealed increased DA turnover in the MPO, AMBH and PMBH, whereas NE turnover was not affected. These results indicate that DA turnover of the incertohypothalamic and of the tuberoinfundibular DA neurons is accelerated by prolactin and that an increased DA turnover in one of these systems is responsible for inhibition of LH release.

Animals↗
PubMed1979

Partial amino acid sequence of glycophorin from porcine erythrocyte membranes.

Glycophorin from porcine erythrocyte membranes was digested with trypsin and chymotrypsin. Some of the peptides were isolated by conventional techniques. The amino acid sequence was determined for two isolated peptides: a chymotryptic glycopeptide of 19 residues and a tryptic peptide of 36 residues which represented the carboxy terminal of the glycophorin.

Amino Acid Sequence↗
PubMed1978

A phase response curve for the locomotor activity rhythm of the rat.

A phase response curve was obtained for the locomotor activity rhythm of the rat. Mus norvegicus albicus, by interrupting a free-running rhythm with light signals of short duration. The response curve obtained was continuous and had the switch-over point at the position of 2 h before the acrophase, followed by the portion of advancing phase shift. The pattern of the curve was typical for the nocturnal rodent.

Adaptation, Physiological↗
PubMed1978

Simultaneous determination of circadian rhythms of locomotor activity and body temperature in the rat.

Stimultaneous determination of the circadian rhythms of locomotor activity and body temperature was carried out in the rat. Deep body temperature was monitored continuously using a telemetric device. The circadian rhythm of locomotor activity was characterized by clustering of several bursts of activity during the dark period. The circadian rhythm of body temperature was also characterized by bursts of small fluctuations which were well correlated with those of locomotor activity. Correlation between the two functions was such that the regression line expressing body temperature as a function of locomotor activity had approximately the same slope for dark and light periods, but a body temperature for a given amount of locomotor activity was significantly higher during the dark period than during the light one. After a prolonged exposure to constant light, the circadian rhythm disappeared in both functions. Both showed bursts of fluctuations which were correlated with each other. These results indicate that the bursts of body temperature increment were dependent on those of the locomotor activity. However, manifestation of the circadian rhythm per se of body temperature could not be explained as resulting exclusively from the circadian fluctuation of locomotor activity.

Animals↗
PubMed1977

Assays and dynamics of corticotropin-releasing factor activity in rat hypothalamus.

Features of several assays for corticotropin-releasing factor (CRF) were compared, with reference to sensitivity, precision, specificity and convenience. In general, in vivo assays are less specific, whereas in vitro assays with isolated pituitary cells appear to suffer from vulnerability. Promising approaches for overcoming this difficulty are appearing: one is the cell culture technique and the other is the perfusion of pituitary cell column. However, the findings with vasopressin are again discordant. So far, the in vivo-in vitro assay system appears to be the most satisfactory. In this connection, special emphasis was laid on the CRF assay by out intrapituitary injection technique through the parapharyngeal approach, which has features of both in vivo and in vitro systems. The drawbacks with this assay are its complexity and relatively lower precision. Problems of the use of dexamethasone are discussed from a viewpoint of possible multistage feedback inhibition, as postulated by Yates et al. Several findings on the CRF dynamics were mentioned, in order to exemplify the findings obtained with our assay: it was shown that the two-peaked changes of CRF after ether-laparotomy stress in adult rats were composed of heterogeneous components, as revealed by differential effect of cycloheximide. Pretreatment with cycloheximide similarly abolished the delayed CRF peak that was observed in 2-day-old neonatal rats under stress. These findings suggest an operation of a biochemical denominator in common with both cases.

Adrenocorticotropic Hormone↗
PubMed1977

Endogenous carbon monoxide production in alloxanized rats.

The endogenous production of carbon monoxide (Vco) in thirty-three diabetic rats induced by alloxan and in fifteen normal rats was measured by serial determinations of the expired carbon monoxide and of the increase of carbon monoxide in the blood during rebreathing in a closed system. Vco (mean +/- S.E., micronl/250g/hr) in the group of alloxanized rats 24, 48, 72, 96, 120 and over 144 hours after the alloxan injection was 6.2 +/- 2.9, 8.4 +/- 2.1, +/- 1.8, 10.7 +/- 3.5, 16.4 +/- 2.0 and 16.5 +/- 2.2, respectively, whereas it was 5.9 +/- 0.4 for the control. This indicates that the alloxanized group maintaining a high blood sugar level for over 120 hours has a three-fold higher Vco than the control.

Animals↗