Biomedical subjects

H Hara

Publications and source records attributed to H Hara.

At least 505 records · Page 28Linked to original sources

PubMed1992

Catecholamine histofluorescence depletion in the infarcted brain parenchyma but not in the adventitia of the occluded cerebral arteries in rats.

The effect of acute cerebral ischemia on the catecholamine-containing nerve fibers in the brain parenchyma and in the adventitia of the cerebral arteries was studied in the rat. Unilateral cerebral ischemia was produced with an intraluminal thread technique which does not damage the adventitia of cerebral arteries. One to three days after surgery the ischemic damage of the brain was consistently observed in the territory of the middle cerebral artery of the operated side. Depletion of catecholamine histofluorescence was observed in the infarcted brain parenchyma. However, in the adventitia of the middle cerebral arteries of the operated side, catecholamine histofluorescence remained intact. No detectable changes in fluorescence were observed in the brain parenchyma or adventitia of the cerebral arteries in the contralateral side. The results indicate that the perivascular catecholamine-containing nerve fibers are not impaired by the intraluminal occlusion of the cerebral artery in the early stage of ischemia.

Animals↗

PubMed1992

Regional variations in particulate cyclic AMP dependent-protein kinase binding activity in the gerbil hippocampus following transient forebrain ischemia by [3H]cyclic AMP binding.

Changes in the binding of [3H]cyclic AMP as an indicator of particulate cyclic AMP-dependent protein kinase (AMP-DPK) binding activity following transient forebrain ischemia were studied in the gerbil using in vitro autoradiography. [3H]Cyclic AMP binding in the strata pyramidale and lacunosum-moleculare of the hippocampal CA1, the stratum pyramidale of the CA3, and the dentate gyrus decreased transiently in the early postischemic phase but then recovered. However, [3H]cyclic AMP binding in the strata pyramidale and radiatum of the CA1, the granular layer of the dentate gyrus, and the upper layer of the cortex decreased again 7 days after ischemia. In the CA4 subfield and the lower layer of the cortex, the binding showed no significant alterations after ischemia. Administration of pentobarbital prior to the induction of ischemia prevented the decrease in [3H]cyclic AMP binding in the CA1 subfield 6 h and 7 days after ischemia, and showed protective effects against neuronal death of the CA1 pyramidal cells 7 days after ischemia. These results indicate that marked alteration of intracellular signal transduction precedes neuronal damage in the hippocampal CA1 subfield. Furthermore, postischemic reduction of [3H]cyclic AMP binding in the histologically intact cerebral cortex, CA3, and dentate gyrus may be the reflection of cellular dysfunction after energy failure.

Animals↗

PubMed1992

Role of apolipoproteins in cholesterol efflux from macrophages to lipid microemulsion: proposal of a putative model for the pre-beta high-density lipoprotein pathway.

Lipid microemulsion of phospholipid and triglyceride with the size of low-density lipoprotein was capable of removing cholesterol from cholesterol-loaded mouse peritoneal macrophages, resulting in reduction of intracellularly accumulated cholesteryl ester. Apolipoproteins (apo) A-I, A-II, C-III, and E bound to the surface of the microemulsion did not modulate the interaction of the microemulsion with the cells in terms of the cholesterol efflux. The cholesterol removal by the microemulsion was enhanced by some 30% only when apoA-I, -A-II, and -E were present in excess to provide their free forms in the medium, but apoC-III did not show such an effect even by its excess amount. The kinetics including the results with apoC-III were consistent with a model that the apparent enhancement was due to generation of pre-beta high-density lipoprotein (HDL)-like particles upon the interaction of free apolipoproteins with macrophages [Hara, H., & Yokoyama, S. (1991) J. Biol. Chem. 266, 3080-3086]. However, pre beta-HDL-like particle was not detected after 6- and 24-h incubation in the medium where cholesterol efflux to the emulsion was maximally enhanced by the apolipoproteins, and cholesterol and phospholipids removed from the cells were all found with the microemulsions. It was also shown separately that the lipids in pre beta-HDL-like particles generated by apoA-I and macrophages were rapidly, within the order of minutes, transferred to the apo-lipoprotein-covered microemulsions when they were incubated together. Thus, the data were consistent with a model that the free form of certain apolipoproteins, such as apoA-I, -A-II, and -E but not apoC-III, generates pre beta-HDL-like particles with cellular lipids in situ and these particles act as mediators for cholesterol transfer from the cells to other lipoproteins.

Apolipoproteins↗

PubMed1992

Continuing evolution in the operative management of primary hyperparathyroidism.

During the past several decades the operation for primary hyperparathyroidism at The University of Chicago, Ill, has changed from subtotal parathyroidectomy for all patients to removal of an adenoma with performance of biopsies of all other glands to bilateral neck exploration, resection of the adenoma, and performance of fewer biopsies of normal glands. During the 1980s, 308 operations were performed; 288 patients underwent first operations. Two hundred forty-five (85.1%) of these patients had an adenoma and forty-three (14.9%) had hyperplasia (multiglandular disease); none had a carcinoma. Resolution of hypercalcemia was achieved in 281 patients (97.5%); seven patients experienced failed explorations. The early cure was the same whether or not preoperative localization studies were performed. Nineteen patients underwent 20 reoperative parathyroidectomies during this period. Preoperative localization studies, done in 16 (80%) of 20 cases, were very helpful. Ninety percent of patients with abnormal parathyroid glands in their neck or mediastinum were cured with their initial reoperation.

Adenoma↗

PubMed1992

The effect of taurine on the age-related decline of the immune response in mice: the restorative effect on the T cell proliferative response to costimulation with ionomycin and phorbol myristate acetate.

1. Proliferative responses to the costimulation with phorbol-12-myristate-13-acetate (PMA) and suboptimal doses of ionomycin in the purified T and B cells from old mice were lower than those from young mice. 2. The degree of the age-related decline was more significant in T cells than in B cells. 3. Taurine, a sulfur containing amino acid, augmented the proliferative responses of T cells from both young and old mice. 4. The augmentation of the proliferative response by taurine was more marked in old T cells than in young T cells. 5. The concentration of intracellular free calcium ion ([Ca2+]i) was significantly lower in old T cells when stimulated with PMA and ionomycin than observed in young T cells. 6. In the presence of taurine, the concentration of [Ca2+]i in the old T cells significantly increased under stimulation by PMA and ionomycin. 7. The results indicate that taurine improved the proliferative response in old T cells by restoration of the increment of the concentration of [Ca2+]i under the stimulation by PMA and ionomycin.

Aging↗

PubMed1992

Extracellular matrix changes of the optic nerve lamina cribrosa in monkey eyes with experimentally chronic glaucoma.

Using light microscopic immunohistochemistry, we studied the immunolocalization and immunoreactivity of the extracellular matrix, including collagen types III, IV, VI, laminin, and alpha elastin in the lamina cribrosa of monkey eyes with normal and experimentally chronic glaucoma. Our results showed: (1) abnormal linearlike immunodeposits of both collagen type IV and laminin in the margin of the lamina cribrosa with significant density in the glaucomatous eyes; (2) the immunoreactivity of collagen type III resembled that of the normal eye, but was slightly stronger at the laminar surface; (3) findings with collagen type VI resembled those of type III with an enhanced linearlike staining surrounding the nerve-fiber bundles. Furthermore, staining of alpha elastin demonstrated dramatic changes in both reactivity and localization. The lamina cribrosa of glaucomatous eyes showed a markedly reduced immunoreactivity as well as an irregular, interrupted pattern. These observations suggest that the changes might be a secondary to the long-standing elevation of intraocular pressure. The alteration of these macromolecules may modify the course of glaucomatous optic damage.

Animals↗

PubMed1992

Beta-thalassemia major resulting from a compound heterozygosity for the beta-globin gene mutation: further evidence for multiple origin and migration of the thalassemia gene.

We describe in a Japanese family beta zero-thalassemia resulting from a compound heterozygosity for a beta-globin gene mutation. One mutation is a C-to-T transition at IVS-2 nucleotide position 654 on the background of Mediterranean haplotype IX. Another mutation is a G-to-A transition at IVS-2 nucleotide position 1, associated with a novel haplotype XI. The occurrence of these mutations on various chromosomal backgrounds provides strong evidence for an interplay of gene migration, interallelic gene conversion, and multiple origins of the same mutation.

Adult↗

PubMed1992

Secretory meningioma associated with numerous meningothelial rosettes.

A case of secretory meningioma with numerous meningothelial rosettes is reported. A 66-year-old man with moyamoya disease gradually developed skull deformity, and underwent surgery for the skull tumor overlying the hemisphere. Histological examination disclosed numerous meningothelial rosettes quite similar to those induced by subarachnoid injection of epinephrine and pseudopsammoma bodies described by Kepes. This may be the first case of meningioma associated with numerous rosette formations.

Aged↗

PubMed1992

Glycerol injection to the rat trigeminal nerve: histological and immunohistochemical studies.

The effect of topical glycerol injection into the rat trigeminal nerves was investigated histologically and immunohistochemically. Anhydrous glycerol was injected into the preganglionic portion of the trigeminal nerves via a ventral approach. Extensive myelin swelling and axonolysis were observed in the rats killed 1 and 2 weeks after glycerol injection. Numerous inflammatory cells were seen especially in the animals sacrificed 1 week after surgery. Myelin disintegration continued up to 4 weeks after glycerol injection. In normal and saline injected sham operated nerves, calcitonin gene-related peptide (CGRP)- and substance P(SP)-like immunoreactivities were densely localized in the nerve fibers. A marked decrease in both CGRP- and SP-like immunofluorescence was seen in the nerves after glycerol injection. The remaining nerve fibers often had blunt endings with increased fluorescence. Swollen and winding structures were also found. These immunohistochemical changes were observed in the rats killed 1 and 2 weeks following surgery. A similar change but of lesser degree was seen in the 4-week-animal. The present study suggests that topical glycerol injection into the trigeminal nerve induces degeneration of the nerves immunoreactive to CGRP and SP. These changes emphasize the putative functional implications of the peptides in relieving the pain of trigeminal neuralgia after topical glycerol injection.

Animals↗

PubMed1992

Alpha-helical requirements for free apolipoproteins to generate HDL and to induce cellular lipid efflux.

The structural requirement has been studied for apolipoproteins in their free form to interact with cells, to generate high density lipoprotein (HDL), and to cause cellular lipid efflux (J. Biol. Chem. 266, 3080-3086, 1991). It is shown that human apolipoprotein (apo) A-IV and apolipophorin III of Manduca sexta cause cholesterol efflux from cholesterol-loaded mouse peritoneal macrophages and reduce intracellularly accumulated cholesteryl ester as a result of forming HDL-like particles with cellular lipids, as do apoA-I, A-II and E. On the other hand, similar to apoC-III, reduced-and-carboxymethylated human apoA-II had no such effect. Thus, apolipoproteins seem to require at least four amphiphilic helical segments per molecule to express this function.

Animals↗

PubMed1992

Increased receptor binding of low-density lipoprotein from individuals consuming a high-carbohydrate, low-saturated-fat diet.

The substitution of saturated fat by complex carbohydrate, according to current dietary recommendations, results in a decrease of plasma and low-density lipoprotein (LDL) cholesterol levels. To determine whether this decrease might result from structural and thus functional changes in LDL particles, the binding internalization and degradation of 125I-LDL were measured using TR715-19 cells, a mutant CHO line into which has been transfected the human LDL receptor, and in which measurements of binding are highly reproducible. Eleven nondiabetic subjects (35 +/- 4 years, 27% +/- 3% body fat) were studied after they had 15% protein, and 560 mg cholesterol/d and the other containing 21% fat (6% saturated), 65% carbohydrate, 14% protein, and 524 mg cholesterol/d.LDL cholesterol levels decreased form 125 +/- 6 to 108 +/- 5 mg/dl (P < .01) on the high-carbohydrate diet. There was an increase in the binding affinity of LDL (Kd 6.6 +/- 2.6 v 7.3 +/- 2.7 micrograms/mL +/- SD; P < .02), and internalization (P < .10), and degradation (P < .05) were also higher. The data suggest that decreasing dietary saturated fat may cause alterations in LDL composition that result in increased receptor clearance; this may partially explain the LDL-decreasing effect of this dietary change.

Adult↗

PubMed1992

Regulation of beta-endorphin receptor expression in mouse spleen cells with Con A and rIL-2.

The expression of the beta-endorphin receptor on both activated and unstimulated mouse spleen cells was studied. Results showed that unstimulated cells have only one type of beta-endorphin receptor with a specific low affinity (Kd = 1.034 +/- 0.0237 x 10(-7) M, 25,000 sites/cell). After Con A stimulation, cells express two types of receptors, one with a low affinity (Kd = 1.034 +/- 0.024 x 10(-7) M, 320,000 sites/cell) and the other with a high affinity (Kd = 1.052 +/- 0.033 x 10(-9) M, 49,000 sites/cell). The kinetic experiments during 4 days after Con A activation indicated that the receptor of high affinity emerged from 24 to 72 h, while the low affinity one increased in number after stimulation. The receptor numbers of both high and low affinity ones reached a maximum peak at 72 h, then began to decline. The addition of exogenous rIL-2 depressed the Con A-induced increment of the receptor numbers of both the high and low affinity ones, but enhanced the proliferative response of the cells. It is suggested that the degree of the expression of the receptors does not simply depend on the mitogenic degree of the cells. In addition, our experiment demonstrated that splenocytes cultured in medium with or without Con A or Con A + rIL-2 for 96 h did not secrete any detectable amount of beta-endorphin with use of the RIA assay, which is sensitive enough to detect the much lower levels of beta-endorphin than that necessary for biological effects. We suggest that the expression of the high affinity beta-endorphin receptor on the activated T-lymphocytes may have to precede the production of IL-2 to potentiate the T-cell proliferative response. The mechanisms and modes of interaction between the neuroendocrine system and the immune system were discussed.

Animals↗

PubMed1992

Effects of aging on signal transmission and transduction systems in the gerbil brain: morphological and autoradiographic study.

The Mongolian gerbil was used as a model of aging because of its relatively short lifespan, genetic homogeneity and the fact that data had been collected previously. Furthermore, gerbils have been widely used in biomedical investigations of stroke and epilepsy. Age-related differences in signal transmission and transduction systems were investigated in brains of three-, 11- and 21-month-old gerbils by morphological and in vitro receptor autoradiographic studies. Morphometric analysis revealed a decreased number of neurons in layer III of the occipital cortex and also a decrease in cerebellar Purkinje cells in 21-month-old animals. However, no statistical differences were observed in the hippocampal formation, the dorsolateral striatum and layer III of the frontal cortex. Autoradiography was used to map muscarinic cholinergic (labeled with [3H]quinuclidinyl benzilate), serotonin2 ([3H]spiperone), dopamine D2 ([3H]spiperone), adenosine A1 ([3H]cyclohexyladenosine), GABAA ([3H]muscimol), naloxone ([3H]naloxone), protein kinase C ([3H]phorbol 12,13-dibutyrate), adenylate cyclase ([3H]forskolin), cyclic AMP ([3H]cyclic AMP) and L-type Ca2+ channels ([3H]PN200-110). Muscarinic cholinergic receptor and protein kinase C, cyclic AMP and L-type Ca2+ channels were significantly decreased in the cerebral cortex and/or in the CA1 subfield of the hippocampus in the 21-month-old group. Muscarinic cholinergic receptor and L-type Ca2+ channel binding sites were significantly reduced in the dentate gyrus. In contrast, protein kinase C was increased in this area in the 21-month-old group. Also, naloxone binding sites were increased in the CA3 subfield, hilus, dentate gyrus and molecular layer of the cerebellum in the 11- and 21-month-old groups. Muscarinic cholinergic, serotonin2 and dopamine D2 receptors and adenylate cyclase were significantly decreased in the striatum. On the other hand, adenosine A1 and GABAA receptors remained unchanged in the 21-month-old group. Although age-related histopathological abnormalities were only observed in the occipital cortex and in the cerebellum, alterations of signal transmission and transduction systems were noticed in all areas examined (e.g. cerebral cortex, CA1 subfield, dentate gyrus and striatum). These data indicate that changes in these receptors and binding sites may be related to dysfunction of learning and memory and to the loss of motor function. The aged gerbil model is a good system for studying aging and is of value for simulating aging after epilepsy and stroke.

Aging↗

PubMed1992

Postischemic binding of [3H]phorbol 12,13-dibutyrate and [3H]inositol 1,4,5-trisphosphate in the gerbil brain: an autoradiographic study.

Postischemic alteration of second messenger systems was investigated in the Mongolian gerbil, utilizing [3H]phorbol 12,13-dibutyrate and [3H]inositol 1,4,5-trisphosphate receptor autoradiography. Transient ischemia was induced for 10 min, and animals were allowed to survive for various recirculation periods of up to one month. [3H]Phorbol 12,13-dibutyrate binding in selectively vulnerable areas showed no significant change 1-24 h after ischemia except for a transient decline in a few regions. Thereafter, the binding in most of the selectively vulnerable areas showed significant alteration 48 h or seven days after ischemia. Interestingly, dentate molecular layer which was resistant to ischemia showed a significant elevation in the number of [3H]phorbol 12,13-dibutyrate binding sites. One month after ischemia, [3H]phorbol 12,13-dibutyrate binding showed significant reduction only in the striatum and the hippocampal CA1 sector where severe neuronal damage was seen morphologically. A significant elevation in the number of [3H]phorbol 12,13-dibutyrate binding sites was still seen in the dentate molecular layer one month after ischemia. In contrast, [3H]inositol 1,4,5-trisphosphate binding showed significant reduction in the selectively vulnerable regions 1-24 h after ischemia. Thereafter, [3H]inositol 1,4,5-trisphosphate binding in most of the selectively vulnerable areas markedly decreased up to one month after ischemia. In the dentate molecular layer, [3H]inositol 1,4,5-trisphosphate binding also showed significant reduction during recirculation except for a slight recovery 48 h and seven days after ischemia. One month after ischemia, the binding in all regions showed significant reduction. These results suggest that postischemic alteration of two second messenger (protein kinase C and inositol 1,4,5-trisphosphate) binding sites was produced with different processes in selectively vulnerable areas.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

Effects of hyperthermia on the effectiveness of MK-801 treatment in the gerbil hippocampus following transient forebrain ischemia.

The effects of dizocilipine maleate (MK-801), a noncompetitive N-methyl-D-aspartate (NMDA) receptor/channel antagonist, were tested on the dysfunction of neurotransmitter and signal transduction systems and morphological damage 7 days after transient forebrain ischemia in gerbils. Neurotransmitter system (adenosine A1, muscarinic cholinergic receptor) and signal transduction system (inositol 1,4,5-trisphosphate receptor: IP3, protein kinase C: PKC, L-type calcium channels) binding sites were mapped by in vitro quantitative receptor autoradiography. All ligands used in the present study decreased significantly in the CA1 subfield 7 days after ischemia. In normothermic animals, pretreatment with MK-801 failed to protect against decreased receptor binding in the hippocampus 7 days after ischemia. Moreover, in a morphological study, pre- and posttreatment of MK-801 failed to show protective effects against ischemic neuronal damage. On the other hand, pretreatment of MK-801, without maintaining body temperature, prevented the neuronal death of CA1 subfield 7 days after ischemia. These results weaken the hypothesis that NMDA receptor/channel may play a pivotal role in the pathogenesis of neuronal damage after transient forebrain ischemia.

Animals↗

PubMed1992

QRS complex changes in the V5 ECG lead during cardiac surgery.

The QRS complex in lead V5 was studied during cardiac surgery. R wave amplitude decreased after induction of anesthesia to approximately 50% to 60% of the preanesthetic level before the institution of CPB (P < 0.001). An rS complex appeared immediately after cardioversion and changed in configuration to an Rs complex 15 to 30 minutes after aortic declamping. The R wave continued to recover toward the preanesthetic level at sternal closure. Patients with coronary artery disease had a poorer recovery of the R wave (P < 0.05) than patients with valvular heart disease; the former recovered to only 50% of the preanesthetic level at sternal closure. Nonsurvivors had much smaller R waves (26.1 +/- 20.5%) than survivors (P < 0.001). The R wave peaked 30 to 40 ms after initiation of the QRS complex, which indicates recovery of conductivity and the activation sequence of the left ventricular (LV) free wall, which is easily disturbed by hypothermia, cardioplegia, and ischemia during aortic cross-clamping. Monitoring QRS complex changes in lead V5 appears to be important on weaning from cardiopulmonary bypass to detect regional ischemia, and also to observe electrophysiologic recovery of the LV free wall.

Adult↗

PubMed1992

Different effects of casein and soyabean protein on gastric emptying of protein and small intestinal transit after spontaneous feeding of diets in rats.

The effects of dietary casein and soyabean-protein isolate (SPI) on gastric emptying and small intestinal transit were observed in rats fed on an 80 g casein or 80 g SPI/kg diet. After a 24 h fast, rats were given 2 g of both the test diets containing 10 g guanidinated casein/kg diet as a marker protein. The amounts of the marker protein remaining in the stomach of the rats fed on the casein or SPI diet were similar and decreased to about 50% after 20 min. The emptying rate then slowed, especially in the casein group, so that the amount leaving the stomach after 1 h in the SPI group was slightly higher (P < 0.05). The small intestinal transit of chyme was estimated by a bolus injection of colloidal carbon suspension or of colloidal carbon and 3H-labelled polyethylene glycol through an implanted duodenal catheter 6 min before death. The average value of transit at 12, 20, 40 and 60 min after feeding of SPI diet was about 25% faster than that after casein diet. The transit velocity of the SPI group was also faster than that of the non-protein group 40 min after feeding. These findings reveal that SPI enhances the small intestinal transit of the liquid phase of chyme. There was no correlation between the gastric emptying of homarginine and small intestinal transit. This result suggest that the small intestinal transit of lumen contents is controlled by the dietary protein regardless of the gastric emptying of protein.

Animals↗

PubMed1992

Infection of terminally differentiated myotubes with Rous sarcoma virus (RSV): lack of DNA integration but presence of RSV mRNA.

We re-examined the generally accepted concept that replication of Rous sarcoma virus (RSV) requires host DNA synthesis. We used terminally differentiated chicken myotubes as the host because chromosomal DNA replication is completely abolished by the natural differentiation process. Southern blot analysis detected unintegrated viral DNA in both the nucleus and cytoplasm of infected myotubes. This indicated that reverse transcription of the infecting viral RNA and transport of the newly synthesized viral DNA into the nucleus proceeded normally in myotubes. However, restriction enzyme digestion of high M(r) DNA prepared from infected myotubes produced none of the fragments specific for RSV, indicating that the viral DNA had failed to integrate into the myotube chromosomal DNA. In these infected myotubes, viral RNA was detected by in situ hybridization. Northern blot analysis showed the presence of all three RSV mRNAs (38S, 28S and 21S). The amount of these viral RNAs in infected myotubes was comparable with that found in infected fibroblasts. We conclude that host DNA synthesis is required for RSV integration, but, in contrast to the generally accepted concept, viral DNA integration is not an absolute requirement for transcription of the RSV genome.

Animals↗