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Biomedical subjects

Y Harada

Publications and source records attributed to Y Harada.

At least 793 records · Page 44Linked to original sources
PubMed1982

Properties of a new complement-dependent bactericidal factor specific for Ra chemotype salmonella in sera of conventional and germ-free mice.

A complement-dependent bactericidal factor, Ra-reactive factor, that acts specifically on Ra chemotype strains of Salmonella was found in sera of eighteen strains of nonimmune mice, including a thymusless strain. The specificity of binding of this factor to the cells of Ra chemotype bacteria was evidenced by absorption studies. The factor was inactivated by treatment with 0.02 M 2-mercaptoethanol or heating for 30 min at 55 degrees C. This factor was present in mice reared by feeding with a chemically defined, antigen-free diet under germ-free conditions. Fetal and newborn mice from a conventional or germ-free mother had the factor, although the titer was lower than the adults'. The titer in the newborn mice reached adult level 1 wk after birth. The titer in the adult mice did not increase markedly after immunization with heat-killed bacteria or administration of Freund's complete adjuvant and turpentine. These results indicate that this factor is actively produced by mice that have never been stimulated with exogenous Ra antigen.

Animals↗
PubMed1981

Cancer of the head and neck in atomic bomb survivors: Hiroshima and Nagasaki, 1957-1976.

A search was conducted in Hiroshima and Nagasaki for all cases of cancer of the lip, nose and nasal cavity, accessory sinuses, larynx, and the oral cavity and pharynx with their subdivisions occurring during the period 1957-1976 among a large, fixed cohort of atomic bomb survivors. A total of 232 cases were identified, of which 154 (66.4%) were histologically confirmed (definite cases). Among definite cases, cancer of the epiglottis and larynx predominated (31.2%), followed by accessory sinus (24.7%) and tongue (18.8%). Of the 154 definite cases, 141 (91.6%) were squamous-cell carcinomas. Only two sarcomas were identified, neither of which was attributable to radiation exposure. Analysis of both total and definite cases, by both total group and major anatomic site, failed to reveal definite evidence of a radiation relationship. Although a suggestive relationship to radiation dose was found for accessory sinus cancers (P = 0.06) among the definite cases, inconsistencies in the data do not permit the conclusion that the incidence of tumors in this group increased as a result of atomic bomb radiation exposure. The medical literature concerning post-irradiation head and neck tumors is briefly reviewed.

Carcinoma, Squamous Cell↗
PubMed1981

Mechanism of kyotorphin-induced release of Met-enkephalin from guinea pig striatum and spinal cord.

The characteristics of kyotorphin (Tyr-Arg)-induced release of Met-enkephalin from the striatum and the spinal cord of guinea pig were determined by superfusing the slices in vitro and then carrying out radioimmunoassays. Depolarization by 50 mM K+ induced a marked release of Met-enkephalin-like immunoreactivity. The potassium-induced release of Met-enkephalin was calcium-dependent. In preparations from a striatum, the addition of kyotorphin to the superfusion medium produced a concentration-dependent increase in Met-enkephalin. The kyotorphin-induced release of Met-enkephalin was calcium-dependent and was abolished by tetrodotoxin. Similar effects of kyotorphin were seen in the spinal cord preparations. Electrical field stimulation of the striatal slices at a frequency of 10 Hz also evoked significant and calcium-dependent increases in the release of Met-enkephalin and markedly enhanced the kyotorphin-induced release of Met-enkephalin, as compared to the controls not given field stimulation. These results suggest that kyotorphin depolarizes the so-called enkephalinergic neurons and releases Met-enkephalin from nerve terminals. This effect of kyotorphin may be a possible mechanism related to the manifestation of analgesia.

Animals↗
PubMed1981

Morphological and electrophysiological evidence for axonal regeneration of axotomized cerebellothalamic neurons in kittens.

Against the current concept of abortive regeneration of axotomized neurons in the mammalian central nervous system, the occurrence of remarkable axonal regeneration of cerebellothalamic projection neurons following transection of the decussation of the superior cerebellar peduncle was proved in kittens morphologically by utilizing anterograde axonal transport of horseradish peroxidase and electrophysiologically by recording the cerebellar-induced cerebral cortical potential. Following axotomy, not only axonal regeneration occurred but also retrograde degeneration of somata which was apparently noticeable as cell loss. The extent of cerebellar nuclear cell loss was inversely related to the extent of regeneration of cerebellofugal axons.

Animals↗
PubMed1981

[Comparative nephrotoxicity of latamoxef and other cephalosporins in rabbits. Combined administration with furosemide or tobramycin. (author's transl)].

I. The nephrotoxic potential of latamoxef (LMOX, 6059-S) was evaluated in male rabbits after combined administration of 500 or 2,000 mg/kg of the compound (ear vein) with subcutaneous injection of furosemide (FUR) at 50 mg/kg. Histological examination of kidney tissues of all animals were performed after 72 hours. Three rabbits were used at each dose level, and comparative studies were performed using several cephalosporins, such as CET and CEZ. Neither LMOX nor CET produced nephrotoxic effects at 500 mg/kg when given in combination with FUR. Although slight elevation of BUN and creatinine in plasma and hyaline casts in lumen of the distal tubules were observed in animals receiving 2,000 mg/kg of LMOX or CET when dosed with FUR, no histological changes were found in renal tissues. Significantly more nephrotoxicity was observed with the treatment of CEZ alone, and this toxicity was augmented in combination with FUR. II. Concomitant administration of LMOX with intramuscular injection of tobramycin (TOB) was estimated in male rabbits. Rabbits received daily intramuscular injection of TOB at 50 mg/kg for 10 days in combination with single dosing of LMOX (500 or 2,000 mg/kg) on the 8th day after the start of TOB treatment. Three rabbits were used at each dose level, and comparative studies were conducted using CET or CEZ. All rabbits were killed 48 hours after the last injection of TOB and examined histopathologically. Combined administrations of LMOX or CET did not aggravate the nephrotoxicity induced by TOB. However, CEZ enhanced renal injuries produced by TOB injection.

Animals↗
PubMed1981

Altered resistance to Listeria monocytogenes in diabetic mice.

Resistance to Listeria monocytogenes (L.M.) in diabetic state was studied using streptozotocin (SZ)-induced diabetic mice. SZ-diabetic mice showed an enhanced resistance to primary listerial infection with a sublethal dose of inoculum, whereas there was no difference between normal and diabetic hosts when challenged with a lethal dose. The growth of L.M. in diabetic mice was inhibited at an early stage of infection. However viable Listeria survived in diabetic mice at a later stage, suggesting the trend of persisting infection. Such enhanced resistance to L.M. in diabetic mice was associated with increased rate of spreading of peritoneal macrophages and with reduction in the level of delayed type hypersensitivity (DTH) to L.M. Therefore, it seemed likely that the enhanced resistance to Listeria in diabetic mice would be due to nonspecifically activated macrophages. Secondary challenge in the immunized animals and transfer experiment with immune spleen cells revealed that the development of protective immunity in diabetic mice was inferior to that in normal mice. Treatment with insulin could hardly influence the altered resistance to L.M. in diabetic mice.

Animals↗