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Biomedical subjects

M Ito

Publications and source records attributed to M Ito.

At least 19 recordsLinked to original sources
PubMed1979

Photochemical reaction of 9-cis-retro-gamma-rhodopsin at low temperatures.

9-cis-Retro-gamma-rhodopsin (lambda max = 420 nm) was prepared from 9-cis-retro-gamma-retinal and cattle opsin. After cooling to liquid nitrogen temperature (77 K), the pigment was irradiated with light at 380 nm. The spectrum shifted to the longer wavelengths, owing to formation of a batho product. This fact indicates that the conjugated double bond system from C-5 to C-8 of the chromophoric retinal in rhodopsin was not necessary for formation of bathorhodopsin. Reirradiation of the batho product with light at wavelengths longer than 520 nm yielded a mixture composed of presumably 9- or 11-cis forms of retro-gamma-rhodopsin. These three isomers are interconvertible by light at liquid nitrogen temperature. Thus the retro-gamma-rhodopsin system is similar in photochemical reaction at 77 K to cattle rhodopsin system. Each system has its own batho product. Based on these results, it was infered that the formation of batho-rhodopsin is due to photoisomerization of the chromophoric retinal of rhodopsin and is not due to translocation of a proton on the ring or on the side chain from C-6 to C-8 of the chromophoric retinal to the Schiff-base nitrogen.

Animals↗
PubMed1979

A new sensitive method for assay of histidase in human skin and detection of heterozygotes for histidinemia.

A new sensitive method was developed for assay of histidase in the stratum corneum of human skin with [14C] histidine as substrate. With this method histidase could be detected using less than 1 mg of stratum corneum. Skin histidase was markedly reduced in seven infants with histidinemia. The enzyme activities in thirteen parents of the patients were about 50% of the normal values, and even the highest values in the parents did not overlap the lowest normal values. Thus heterozygotes in the autosomal recessive form of histidinemia can be distinguished from normal persons by their skin histidase activity measured by this sensitive assay method.

Adult↗
PubMed1979

Interaction between the horizontal vestibulo-ocular reflex and optokinetic response in rabbits.

Dynamic characteristics of the horizontal vestibulo-ocular reflex (HVOR), the optokinetic response (OKR), and their interactions were investigated in alert albino rabbits. For stimulation of the horizontal semicircular canals, the whole rabbit was rotated sinusoidally on a motor-driven turntable at peak-to-peak amplitudes of 5 degrees to 30 degrees over a frequency range of 1/30 to 1/2 Hz. Optokinetic stimulation was provided by a narrow vertical slit light source presented in front of the eye to be tested. The evoked horizontal eye movements were observed and measured by means of a closed circuit television system adapted to provide an analog signal proportional to the eye movement. The net HVOR was obtained by rotation of the turntable in darkness and the net OKR by rotation of the light source. Combining rotation of the turntable with a stationary light source immediately increased the gain and reduced the phase shift of the HVOR. The light source moving in phase with the turntable, but at twice the angular amplitude, reduced the gain and advanced the phase of the HVOR. Eye movement curves of the HVOR modified by a fixed or moving slit light could be reconstructed approximately by a linear combination of the net HVOR and OKR.

Animals↗
PubMed1979

Adaptive modification of the rabbit's horizontal vestibulo-ocular reflex during sustained vestibular and optokinetic stimulation.

Adaptability of the horizontal vestibulo-ocular reflex (HVOR) and the optokinetic response (OKR) was examined in alert albino rabbits during sustained runs lasting 5--12 h under four different stimulus conditions. (1) Sinusoidal rotation of the rabbit in darkness by 5 degrees at 1/10 Hz, or (2) sinusoidal movement of a vertical slit light by 2.5 degrees of 5 degrees at 1/10 Hz around the optical axis of the stationary rabbit, affected the gain of neither the HVOR nor the OKR. (3) Combination of the stimulus as in (1) with the stationary slit light increased the gain of the HVOR gradually. A plateau at about 140% of the initial control was reached in 5 h. (4) Combination of the stimulus as in (1) with the slit light movement by 10 degrees in phase with the turntable decreased the HVOR gain gradually, a plateau being obtained at about 70% of the initial control in 5 h. Changes of the HVOR gain induced in conditions (3) and (4) were not frequency-specific and accompanied by no signficant modification of either the gain or phase of the OKR or the linear property of HVOR-OKR interaction. A small but significant change of the HVOR phase was also detected under the condition (3) but not (4).

Adaptation, Ocular↗
PubMed1979

A clinical study of tuberculous colitis.

During the last 8 years, the diagnosis of tuberculous colitis has been made radiologically in 22 cases. Twelve were confirmed by histological or bacteriological evidences. The X-ray findings are classified into three types as follows: Type A, showing an extensive scarred area in the ileocecum and ascending colon. Type B, showing annular stricture in the ascending colon and dilatation of its oral side. Type C, showing pouchformation (pseudo-diverticulum) and deformity in the cecum. We emphasize that histological examination and culture of the biopsy specimens by endoscopy were useful for the diagnosis of tuberculous colitis. Furthermore, radiologic changes of the colon by administration of antituberculous drugs were observed.

Adult↗
PubMed1979

Tuberous sclerosis: early neurologic manifestations and CT features in 18 patients.

Early clinical manifestations and radiologic features of tuberous sclerosis were studied in 18 consecutive patients encountered in the past two years, including two patients harboring an associated intraventricular tumor (giant-cell astrocytoma). Depigmented naevi rather than adenoma sebaceum, infantile spasms and intracranial calcifications were the cardinal early features in this present series, and CT scanning proved to be the single most useful diagnostic technique in the early detection of intracranial calcifications and therefore for the early diagnosis of this disorder. CT scanning was also useful in detecting the intraventricular tumors in the early stage before they became clinically manifest.

Adolescent↗
PubMed1979

Computed tomography of cerebral palsy: evaluation of brain damage by volume index of CSF space.

Between 1976 and 1978, we examined 110 Japanese children with cerebral palsy using a CT 1000 and a CT 1010 (EMI). In 92% of all patients, there were abnormal findings. Cortical atrophy was seen in 51%, ventricular dilatation in 86%, localized low density areas in 22%, brain anomalies in 10% and asymmetry of cerebral hemisphere in 31%. In spastic hemiplegia, the characteristic CT revealed asymmetrical ventricular dilatation without cortical atrophy and localized low density areas in the cerebral hemisphere contralateral to the palsy. In spastic tetraplegia, CT revealed moderate to marked diffuse cerebral atrophy or brain anomalies. In athetosis, CT revealed normal or slight cerebral atrophy. In 60 cases where a CT 1010 was used, we calculated the volume index of CSF space by computer, Eclipse S/200, and analyzed the relationship between the clinical features of cerebral palsy and the volume index of CSF space.

Adolescent↗
PubMed1979

Responses of vibrissa-sensitive cortical neurons in normal and prenatally X-irradiated rat.

1. Rats were irradiated by 200 R of X ray on day 17 (the 18th day) of gestation through the body wall of the mother. When they underwent the following electrophysiological tests at the age of 3-4 mo, the somatosensory cortex showed a lack of layers II, III, IV, and Va, as described by previous investigators (3, 4). 2. Spike responses to quick whisker deflections were recorded from single cells in the somatosenory cortex of normal and prenatally X-irradiated rats. 3. In normal animals, single units often responded to several whiskers, but the magnitudes (response latency and firing probability) of the responses were graded around a whisker in the "center" of the field that gave rise to the strongest response. During electrode penetration perpendicular to the cortical surface, such a center remained unchanged or shifted to another whisker that was immediately adjacent. As for the large-sized, initially positive unitary spikes (typically 2 mV or higher) sampled in this study, no systematic change in the response latency, the size of receptive field, or response probability was detected during the penetration. 4. The above description holds also for the irradiated rats except that the response latency was prolonged when compared to the normal controls. 5. Cortical laminar analysis of field potentials revealed that while the earliest electric sink appeared in layer IV in the controls, that in the irradiated rats was observed in layer Vb. However, there was no difference in the latency of these potentials between the two groups, suggesting that vibrissal sensory signals reach the cortical level normally even in the irradiated rats. The prolonged latency of the irradiated cortical neuronal response could thus be ascribed to an abnormal intracortical delay, which was most likely associated with the failure of development of layer IV stellate cells in these preparations. 6. A possibility as to how the layer IV stellate cells are involved in input-output relationships in the normal somatosensory cortex is presented and discussed.

Animals↗
PubMed1979

Changes in connective tissue components in ulcer tissue during the healing process of acetic acid ulcer in rats.

In order to elucidate the role of connective tissue components on the repair of ulcerated regions, quantitative changes in chemical components in ulcer tissue during the healing process were investigated in acetic acid-induced ulcer in rats. The ulcer index showed a peak on the 5th day after the operation, declined rapidly and maintained a slight level the 15th to the 60th days, without a complete recovery. In ulcer tissue, sialic acid and hexosamine remarkably increased in the early stages of healing, showing a peak on the 5th day. The patterns of time course of changes in both components ran almost parallel with those in the ulcer index. Uronic acid maintained slightly higher levels than normal levels the 5th to the 60th days. Hydroxyproline continued to increase with the time course from the 25th day. When acid mucopolysaccharides in ulcer tissue were isolated into various fractions, there were increases in hyaluronic acid on the 5th day, in chondroitin sulfate A and chondroitin sulfate C on the 30th day and chondroitin sulfate B on the 60th day, respectively. Significance of changes in these components in the healing process is discussed.

Acetates↗
PubMed1979

Studies on the mechanism of action of cetraxate [4'-(2-carboxyethyl)phenyl trans-4-aminomethyl cyclohexanecarboxylate hydrochloride], a new anti-ulcer agent.

To elucidate mechanisms involved in the anti-ulcer action of cetraxate, the effects of this agent on the ulcer index (UI), fibrinolytic activity (FA) and contents of several connective tissue components in ulcer tissue were examined using aspirin- and acetic acid ulcers in rats. In aspirin ulcer, cetraxate (100 and 300 mg/kg p.o.), like tranexamic acid (500 mg/kg p.o.), epsilon-aminocaproic acid (500 mg/kg p.o.) and gefarnate (200 mg/kg p.o.), inhibited both the UI and FA. However, aluminum sucrose sulfate (1000 mg/kg p.o.) was effective only against the UI and L-glutamine (500 mg/kg p.o.) failed to inhibit both parameters. In acetic acid ulcer, following oral, daily X either 5 or 8 administrations, cetraxate (200 and 300 mg/kg), gefarnate (200 mg/kg), aluminum sucrose sulfate (1000 mg/kg) and L-glutamine (500 mg/kg) were effective on both the UI and FA. Tranexamic acid (500 mg/kg) and epsilon-aminocaproic acid (500 mg/kg) were ineffective on the UI, although both agents inhibited FA. In acetic acid ulcer, cetraxate induced increases in hexosamine and uronic acid, that is, acid mucopolysaccharides (AMPS), especially chondroitin sulfate A and -C, whereas L-glutamine and aluminum sucrose sulfate resulted in increases in hexosamine and sialic acid, that is, glycoproteins. From these results, cetraxate may mainly accelerate the ulcer healing by increasing AMPS in ulcer tissue. Moreover, the local anti-FA property of this agent may be also beneficial in treating bleeding ulcers.

Acetates↗
PubMed1979

Significance of skin pressure in body heat balance.

It has been demonstrated by Takagi and his colleagues that pressure on a specified area of the body surface causes depression of sweating in a certain body division and changes in the relative sweat rates between body divisions. Furthermore, skin pressure has been assumed to suppress the central thermoregulatory activity, thus bringing about a rise or fall in body temperature in a hot or cool environment, respectively. We examined the effect of skin pressure applied to the bilateral subaxillary regions on body heat balance by means of continuous recordings of evaporative weight loss (total sweat rate), local sweat rates at various areas and rectal and skin temperatures and measurements of metabolic rate. Most experiments were carried out at a room temperature of 36 degrees C with 40% rh and a few were done at 27 degrees C in the absence of thermal sweating. Various strengths of pressure up to 5 kg/50 cm2 were employed. It was observed that the total sweat rate was either unchanged, decreased or occasionally even increased. There was an apparent tendency that the stronger the pressure was, the more depressed was the total sweating. A weaker pressure, on the other hand, often caused facilitation of total sweating. Changes in rectal and mean body temperatures and in metabolic rate were minimal in the majority of cases, and bore no relationship to the changes in the total sweat rate. These results offer no evidence that skin pressure of up to 5 kg/50 cm2 affects human central thermoregulatory activity but suggest that it may exert a sweat-inhibitory effect, primarily through the interaction of sudomotor impulses somewhere along the efferent pathways, possibly at the spinal segmental level.

Adult↗