Publications by authors named "Iriki M"

This article reviews 40 years of research (1970-2010) into the capability of the efferent sympathetic nervous system to display differential responsiveness. Discovered first were antagonistic changes of activity in sympathetic filaments innervating functionally different sections of the cardiovascular system in response to thermal stimulation. During the subsequent four decades of investigation, a multitude of differential sympathetic efferent response patterns were identified, ranging from opposing activity changes at the level of multi-fiber filaments innervating different organs to the level of single fibers controlling functionally different structures in the same organ.

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The incidence of heat disorders in July and August during 10 yr (1995-2004) reported for the population of Yamanashi prefecture was analyzed, with special consideration of an aging society, in relation to levels and patterns of phases with high daily maximal temperatures. There was an increasing tendency for years with hot summers in comparison to preceding decades. Two climatic characteristics associated with increased incidence of heat disorders have become apparent: first, sustained phases of atmospheric temperatures exceeding approximately 32 degrees C, second, rapid onset of phases with high maximal temperature after preceding phases of relatively cool weather.

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The detection of surface and internal temperatures is achieved by axons terminating at lamina I of the spinal dorsal horn, otherwise approached only by nociceptive afferents. Recent advances in thermal physiology research have disclosed that temperature-sensitive ion channels belonging to the "transient receptor potential" family exist in the peripheral sensory neurons and in the brain. Thermosensory, nociceptive and polymodal afferents project to different thalamic nuclei, and specific pathways to the insular cortex evoke the conscious experience of thermal sensation.

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Objectives: To examine differences in views on geriatrics education at the undergraduate level between Japan and other industrialized countries, including the United Kingdom.

Design: We conducted a nationwide survey of professorial staff responsible for undergraduate education in all medical schools in Japan, and an international survey of 37 medical schools and geriatric institutes in other industrialized countries, including 16 medical schools in the United Kingdom.

Results: The results indicate that undergraduate education in geriatrics in Japan emphasizes the theoretical aspects of the aging process and the features of diseases in the elderly, and lacks attention to the practical aspects of care.

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The increase in the number and proportion of the elderly in Japan over the last 30 years has been faster than that in any other country. One of the measures we are compelled to take to deal with this drastic change in medicosocial circumstances is reform of the medical school curriculum. However, the necessary reforms are being implemented slowly and are still insufficient.

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The role of endogenous angiotensin II (ANG II) at the level of the rostral (RVLM) and caudal ventrolateral medulla (CVLM) in the control of sympathetic baroreflex function was investigated in urethan-anesthetized rabbits. The baroreflex relationship between mean arterial pressure and integrated renal sympathetic nerve activity (RSNA) was compared before and during microinfusion of saralasin, an ANG II receptor antagonist into RVLM or CVLM. The infusion of saralasin (20 pmol/min) into RVLM reduced the upper plateau, the range, and the range-dependent gain of the baroreflex, as well as the resting level of RSNA.

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Article Synopsis
  • The review aims to guide the future of undergraduate education in geriatric medicine in Japan by analyzing current practices in western countries.
  • In the UK, geriatric medicine training is robust, with most universities having dedicated departments and mandatory courses, while in the US, it is mostly elective and faces a shortage of faculty.
  • There is a need for increased clinical and basic research in geriatric medicine and gerontology to inspire more individuals to enter the field.
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With the aging of Japan's population, physicians need to be aware of advances in geriatric medicine. To assess the status of geriatric medicine in undergraduate education, we surveyed of medical student's opinions on gerontology and geriatric medicine. A questionnaire was sent to six-year medical students at a total of 20 schools that did not include geriatric medicine in their curriculum.

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With the rapid aging of Japan's population, medical professionals who specialize in geriatric medicine are in unprecedented demand. To meet that demand and to improve the curriculum for teaching geriatric medicine and gerontology in Japan, we surveyed medical students' understandings of these specialties. Students at 14 schools with classes in geriatric medicine and gerontology were surveyed.

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Article Synopsis
  • Undergraduate education in gerontology and geriatric medicine is increasingly crucial due to the growing elderly population.
  • A questionnaire was distributed to professors from 14 medical schools to evaluate geriatric medicine curricula and gather their perspectives on an ideal curriculum.
  • Responses indicated that while all schools offer lectures in geriatric medicine, the total hours vary significantly, and there is a general consensus that more emphasis on bedside teaching is needed.
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Because the number of people who reach an advanced age has been increasing at an unprecedented rate in Japan, geriatricians are expected to play a central role in health care for the elderly. However, only 16 out of 80 medical schools (20 percent) now have departments of geriatrics for undergraduate education. To develop undergraduate education in the field of geriatrics, a survey was sponsored by the Research Projects on Aging and Health (Health Science Research Grant the Ministry of Health and Welfare of Japan).

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  • The study investigated how procaine injections into specific brain regions impact the heat production in urethane-anesthetized rats, measuring temperature changes in brown adipose tissue and rectum.
  • The most significant temperature increase occurred upon injection in the lower midbrain, indicating that this area plays a crucial role in regulating body temperature.
  • The findings suggest that inhibiting certain brain functions with procaine leads to increased temperature through heightened sympathetic nervous system activity, validating the existence of a tonic inhibitory mechanism on heat production in the lower midbrain.
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  • The study evaluated how R-R intervals and their variability (CVR-R) can indicate thermal comfort levels in a controlled environment.
  • Ten male subjects participated, reporting sensations of thermal comfort while their heart rates and skin temperatures were monitored at three different temperatures (20°C, 26°C, and 30°C).
  • Results showed that cold conditions (20°C) led to lower skin temperatures and higher heart rates, indicating discomfort, while warmer conditions (30°C) caused increased skin temperatures and fluctuating heart rates, also resulting in discomfort among participants.
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Experiments were designed to clarify the role of the brain's organum vasculosum laminae terminalis (OVLT) in the development of fever in rabbits. Rectal and ear skin temperatures were recorded in conscious animals in which the OVLT had been electrolytically destroyed or in which the preoptic anterior hypothalamus (PO/AH) had been transected bilaterally. When the OVLT had been ablated the febrile responses to intravenous injection of interleukin-1 beta (IL-1 beta) or tumour necrosis factor alpha were significantly attenuated, while those to intracerebroventricular injection of IL-1 beta were not affected.

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General anesthetic agents have central and peripheral effects on body temperature regulation, and its alterations are related to the depth of anesthesia. To evaluate the effect of halothane and enflurane on thermoregulation, we investigated the threshold of body core temperatures to induce peripheral vasoconstriction and shivering in spontaneously breathing rabbits. Rabbits were anesthetized with halothane or enflurane at 0.

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  • The study explored how TNF alpha causes fever in rabbits and found that IL-1 beta is not a major factor in this process.
  • Pre-treatment with anti-IL-1 beta antiserum blocked the fever response to IL-1 beta but had no effect on fever caused by TNF alpha.
  • The findings suggest that while IL-1 beta may not contribute to TNF alpha-induced fever, the opioid system in the brain plays a role in this fever mechanism.
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Effects of injection of 1-oleoyl-2-docosahexaenoyl-sn-glycero-3-phosphorylcholine (ODHPC) on learning ability were investigated in rats using discriminatory shock avoidance learning task. When ODHPC (2 mumol) was intraperitonealy administered 5 min before the beginning of the first trial of learning task from the second to fifth sessions, avoiding rates of the ODHPC-injected group were significantly higher than those of the control group. However, any injection of ODHPC derivatives, such as 1-oleoyl-2-docosahexaenoyl-diacylglycerol, 1,2-dioleoyl-sn-glycero-3-phosphorylcholine, glycerophosphorylcholine, docosahexaenoate, oleate and choline chloride, did not affect learning.

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  • The study examined the effects of administering O-DH-PC, a type of lecithin, and GPC on sleep in male F344 rats.
  • O-DH-PC significantly increased both paradoxical sleep time and total sleep time 24 hours after administration at a dose of 10 micrograms per rat.
  • The findings suggest that the sleep-enhancing effects of O-DH-PC are linked to its fatty acid components rather than its choline content.
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We have evaluated a new infrared tympanic thermometer, IT-10, as an intraoperative temperature monitor in patients with or without open abdominal surgery. It determines temperature by measuring infrared radiation given off by a warm object. Temperatures measured with this device were closely correlated with those measured with rectal and bladder thermometries.

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  • The study examined how TRH and its analog NS-3 affect body temperature and blood circulation.
  • Both NS-3 and TRH increased body temperature, metabolic rate, and heart-related activities in rabbits.
  • NS-3 proved to be more potent than TRH overall, but exhibited varying levels of potency across different physiological effects.
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Although suppression of thermoregulatory mechanisms by anesthetics is generally assumed, the extent to which thermoregulatory responses are active during general anesthesia is not known. To evaluate the effect of anesthetics on thermoregulation, we investigated the threshold body core temperatures to induce peripheral cutaneous vasoconstriction and shivering in spontaneously breathing rabbits. Rabbits are anesthetized with halothane at 0.

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  • The study examined how cool temperatures affect the contraction of smooth muscle in guinea pig taenia caeci when exposed to neurotransmitters like acetylcholine (ACh) and 5-hydroxytryptamine (5-HT).
  • Lower temperatures (30°C) were found to significantly increase the contraction response to both ACh and 5-HT compared to body temperature (37°C).
  • The results suggest that the enhanced contractile response at lower temperatures might involve increased intracellular calcium levels, as indicated by stronger contractions when calcium and caffeine were introduced at cooler temperatures.
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Interleukin-1 (IL-1) is now generally accepted as an endogenous pyrogenic mediator of fever induction. IL-1 induces fever by means of activation of arachidonate metabolism in the brain. However, whether circulating IL-1 enters the brain or not, further, the question of where is the action site of circulating IL-1 on the brain, have not been clearly demonstrated.

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The effect of propiverine hydrochloride (P-4) on the function of the bladder in decerebrated dogs was compared with that of propantheline, an anticholinergic drug which is used for the treatment of micturitional disorders. P-4 (5 and 10 mg/kg, i.v.

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