Biomedical subjects

H Matoba

Publications and source records attributed to H Matoba.

31 records · Page 2Linked to original sources

PubMed1992

Triphenyltin-induced increase in the intracellular Ca2+ of dissociated mammalian CNS neuron: its independence from voltage-dependent Ca2+ channels.

To test the possibility that triphenyltin (TPT) increases the intracellular Ca2+ ([Ca2+]i) in neurons as found previously in thymocytes, the effect of TPT on [Ca2+]i was examined in rat cerebellar neurons by a flow-cytometer with fluorescent dyes. TPT at concentrations ranging from 3 x 10(-7) M to 1 x 10(-5) M dose-dependently increased the [Ca2+]i. The TPT-induced increase in [Ca2+]i was not attenuated by a Ca2+ channel blocker, suggesting that it was not dependent on voltage-dependent Ca2+ channels. As the concentration of external Ca2+ ([Ca2+]e) increased, TPT produced a more profound increase in the [Ca2+]i. However, the increase in the [Ca2+]i by TPT was observed even in nominally [Ca2+]e-free solution. These results suggest two possibilities. First, TPT may promote Ca(2+)-influx to the neuron. Secondly, TPT may affect the intracellular Ca-store sites. This study is relevant to the neurotoxicity of organotins because it has become progressively clear that sustained increases in the [Ca2+]i can activate various Ca(2+)-dependent degradative processes.

Animals↗

PubMed1991

[Endophthalmitis in Japan--a nationwide study with reference to type and etiology].

A nationwide clinical study on bacterial and fungal endophthalmitis was done with special reference to their type and etiology. Two hundred and eighty cases of endophthalmitis were reviewed. All cases were divided into two categories such as exogenous (trauma, surgery, and ulcer) and endogenous (metastasis). Penetrating trauma was responsible for 93 cases (33.2%), surgery for 88 cases (31.4%), ulcer for 11 cases (3.9%) and metastasis for 88 cases (31.4%). Out of the 280 cases, 79 cases (28.2%) were microbiologically diagnosed through aqueous or vitreous tap or biopsy. The total numbers of isolated organisms amounted to 87 consisting of 43 Gram-positive bacteria, 30 Gram-negative bacteria and 14 fungi. The positive isolation was 31 out of 86 (36%) from the aqueous and 52 out of 103 (50%) from the vitreous. Exogenous types associated with trauma, surgery or ulcer were mainly caused by Gram-positive bacteria of 37 strains, led by coagulase-negative staphylococci in 14 cases. On the other hand, endogenous cases were mainly due to Gram-negative bacteria of 14 strains including Klebsiella pneumoniae in 5 cases, E. coli in 4 cases and fungi of 11 strains including candida spp in 9 cases.

Adolescent↗

PubMed1990

Muscle responses of thoroughbreds to conventional race training and detraining.

Ten healthy sedentary Thoroughbreds with previous race training experience were trained conventionally for 9 weeks. Muscle biopsy samples were obtained before and after training and after 6 weeks of detraining pasture rest. Biopsy samples were obtained from the right deltoid, triceps, vastus lateralis, middle gluteal, biceps femoris, and semitendinosus muscles. The deep-frozen biopsy samples were analyzed for activities of succinate dehydrogenase (SDH), 3-hydroxy-acylcoenzyme A dehydrogenase (HAD), and phosphorylase (PHOS) and for glycogen concentration. The triceps and gluteal muscle samples were also serially sectioned and stained for myofibrillar actomyosin adenosine triphosphatase (ATPase) activity after alkaline (pH 10.3) and sequential acidic (pH 4.34) ATPase inactivation. Fiber types I (alkaline preincubation), IIA1, IIA2, and IIA3 (sequential acidic preincubation over 5 minutes) were identified and were evaluated for fiber-type distribution and fiber areas. Increases in response to training were observed in deltoid and vastus muscle SDH and gluteal muscle HAD activities, and deltoid muscle glycogen concentration (P less than 0.05 to P less than 0.01). Changes in PHOS activity were not observed. Type-IIA1, -IIA2, and -IIA3 fiber areas in triceps muscle were increased in response to training (P less than 0.05 to P less than 0.01). Changes in fiber-type distribution did not occur in response to training. Changes in muscle enzyme activities, glycogen concentration, fiber types, and fiber areas were not seen from posttraining to detraining. Further increases were observed when detraining values were compared with pretraining values in deltoid, triceps, vastus, gluteal, and biceps femoris muscle SDH activities and in gluteal muscle glycogen concentration (P less than 0.05 to P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

3-Hydroxyacyl CoA Dehydrogenases↗

PubMed1986

[A histochemical study on postnatal growth of the soleus muscles of male and female mice].

Postnatal changes in histochemical properties of the soleus muscles were examined in male and female mice aged 5 to 40 weeks. The fiber type composition did not significantly differ between sexes 5 weeks after birth. In males the percentage of type I fibers increased from 5 to 22 weeks of age but did not change thereafter. In females the percentage of type I fibers increased from 5 to 40 weeks of age. As a result, females had significantly higher percentage of type I fibers than males 30 and 40 weeks after birth. The smaller increase in the percentage of type I fibers during postnatal growth in males is suggested to be attributable to the higher testosterone level. In males the cross-sectional area of both type I and type II fibers increased with age. In females, however, the cross-sectional area of type II fibers increased with age whereas that of type I fibers increased from 5 to 10 weeks of age but thereafter decreased gradually. The ratio of mean fiber cross-sectional area of type I fibers to that of type II fibers decreased slightly from 5 to 10 weeks of age but did not change thereafter in males. In females the ratio increased from 5 to 10 weeks but thereafter decreased gradually. The ratio was significantly higher in females than in males in all age groups. The percentage area occupied by type I fibers increased with age in both sexes. The increase was greater in females than in males, however. Furthermore, females had significantly higher value than males in all age groups. No significant age difference and sex difference were observed in the total number of muscle fibers.

Animals↗

PubMed1985

Comparison of fiber types in skeletal muscles from ten animal species based on sensitivity of the myofibrillar actomyosin ATPase to acid or copper.

Comparisons were made of the histochemical characteristics of skeletal muscle from 10 animal species. The basic comparison was made from the staining patterns for the myofibrillar actomyosin ATPase produced by preincubation of fresh frozen cross-sections of muscle at alkaline pH (10.30) or acid pH (4.60) with those produced by preincubation in media containing Cu2+ at alkaline pH (10.30), near neutral pH (7.40), or acid pH (4.60). Muscle sections were also stained for reduced nicotinamide adenine dinucleotide tetrazolium reductase and alpha-glycerophosphate dehydrogenase to provide an indication of the relative oxidative and glycolytic capacity of the different fiber types. Type II fibers in mixed fibered muscles were either very sensitive, moderately sensitive, or relatively insensitive to inactivation of the myofibrillar actomyosin ATPase after acid preincubation. These fibers were identified as type IIA1, IIA2, and IIA3, respectively. The myofibrillar actomyosin ATPase of the type I fibers of these muscles, with the exception of those in mouse muscle, was activated by pretreatment with acid. A separation of animal species was possible based on the stability of the IIA1 fibers to inclusion of Cu2+ in the preincubation medium. For one group of animals (rat, mouse, monkey, man, dog, rabbit, and cow), a reciprocal relationship existed between lability to acid and stability to Cu2+ for type IIA1 and IIA3 fibers, respectively. For the second group of animals (horse, ass, and cat) there was a parallel relationship between lability or stability of the type IIA1 and IIA3 fibers to pretreatment with either acid or Cu2+.

Actomyosin↗

PubMed1984

Identification of fiber types in rat skeletal muscle based on the sensitivity of myofibrillar actomyosin ATPase to copper.

Experiments are reported demonstrating that differential rates of inactivation of the histochemical staining for myofibrillar actomyosin ATPase in rat skeletal muscle fibers exist following inclusion of low concentrations of Cu2+ in the preincubation medium. This response of rat muscle occurs at near neutral (7.40), acid (4.60), and alkaline (10.30) pH. The response to Cu2+ appears to result from a binding of Cu2+ onto the myofibrillar complex, probably on myosin itself, as it can be reversed by soaking of the pretreated muscle sections in sodium cyanide or the Cu2+ chelator diethyldithiocarbamate. The pattern of modification of the staining pattern following pretreatment with Cu2+ is the mirror image of that produced by pretreatment with acid. The results demonstrate that the inclusion of Cu2+ in the preincubation media for the myofibrillar actomyosin ATPase can be a useful tool to differentiate fiber types. They also support the earlier conclusion that three distinct types of type II fibers can be identified in rat skeletal muscle based on the histochemical staining for myofibrillar actomyosin ATPase.

Adenosine Triphosphatases↗

PubMed1984

Influence of exercise on the fiber composition of skeletal muscle.

Biopsy samples from the vastus lateralis muscle (VLM) of man were examined for fiber composition at rest and at selected intervals during prolonged exercise ranging in intensity from 40% to 75% of the total body maximal oxygen uptake (VO2max) and one-min bouts of exercise at 150% VO2max. Because of the heterogeneity of fibers in human VLM, studies were also completed where the effect of exercise on the fiber composition of the rat soleus muscle (SM) was examined. In some animals the SM from one hindlimb was removed 9 days prior to their being exercised after which the remaining SM was removed. Exercise reduced muscle glycogen in all experiments. In the studies with man, blood lactate exceeded 17 mmoles/l after the heavy exercise but was largely unchanged by endurance exercise. Colonic temperature of the exercised rats exceeded 40 degrees C. In studies where fibers were identified only as type I and type II, type II fibers in the VLM of all samples (16) taken at rest averaged 61.2 +/- 12.5% as compared to 59.0 +/- 12.0% after exercise (54 biopsy samples). In a second series of studies with man where the subtypes of type II fibers were identified, there were also no differences in fiber composition of the VLM after varying periods of exercise. Glycogen content and percent fiber composition were the same in right and left SM obtained from rested rats. Exercise (30 to 40 min) did not alter the fiber composition of the rat SM. These data demonstrate that the histochemically demonstratable myofibrillar actomyosin ATPase of skeletal muscle is not altered by a single exercise bout.

Adenosine Triphosphatases↗

PubMed1984

Influence of ionic composition, buffering agent, and pH on the histochemical demonstration of myofibrillar actomyosin ATPase.

The influence of the composition of the preincubation medium on the histochemical demonstration of myofibrillar actomyosin ATPase, including a variety of carboxylic acid and non-carboxylic acid buffering compounds and neutral salts, was studied. In inorganic salt-free systems the rate of the activation of type I fibers and inactivation of type II fibers was accelerated when the carboxylic acids had longer chain length or multiple carboxyl groups. Of these factors, the number of carboxyl groups was dominant with a 100 mM citrate buffer producing a sharp differentiation between fiber types. In contrast, the time course of the response was exceptionally long in an acetate buffer. The time course of the ATPase reaction was also modified by other buffers at pH 4.60. The most notable were an ascorbate - glycine buffer system which produced little or no deviation from the alkaline preincubation staining pattern after prolonged preincubation and a pyrophosphate system which produced a rapid change. Neutral salts in the preincubation medium accelerated the time course of the inactivation - activation process with the order for the halogen salts of K+ being F- less than Cl- less than Br- less than I-, which is a progression by molecular weight. The only sequence for cations on the myofibrillar actomyosin ATPase was Li+ less than Na+ less than K+. The response to salts was concentration dependent. An interaction existed between buffering compound, type of salt, and pH. These experiments demonstrate that the histochemical differentiation of fiber types by the myofibrillar actomyosin ATPase reaction depends upon a modification of some component(s) of the myofibrillar complex that can be influenced by a number of factors.

Adenosine Triphosphatases↗

PubMed1984

Role of carbohydrate in exercise.

Carbohydrate is an important energy source during exercise. During short, heavy exercise it may be the only energy source for the working muscle and may be derived exclusively from the glycogen stores within the muscle fibers themselves. During prolonged, submaximal exercise the magnitude of the contribution that carbohydrate makes to the total fuel consumed depends upon a number of factors, including (1) the intensity of the exercise, (2) the duration of the exercise, (3) the state or type of training that the individual has engaged in, or both, and (4) the diet previously consumed. Due to their limited storage in the body and the relative ease with which these stores can be manipulated by combinations of diet and/or training, a knowledge of the dynamics of carbohydrate metabolism is an important component in the arsenal of knowledge for coaches and athletes.

Blood Glucose↗

PubMed1981

Histochemical changes of rat skeletal muscles induced by cold acclimation.

After cold acclimation of rats the augmentation of succinic dehydrogenase activity in the fast-twitch oxidative glycolytic (FOG) and the slow-twitch oxidative (SO) fibers was observed in entire regions of the soleus, the extensor digitorum longus, the plantaris, the longissimus and the gastrocnemius muscles. Furthermore, a tendency to increased proportion of the FOG and the SO fibers was observed more prominently in superficial regions than in deep regions of a large muscle such as the gastrocnemius muscle.

Adaptation, Physiological↗

PubMedDate not supplied

Treatment of Vogt-Koyanagi- Harada's disease during pregnancy.

BACKGROUND: Caution should be exercised in treating patients with autoimmune diseases during pregnancy. CASES: We successfully treated three cases of Vogt-Koyanagi-Harada's disease (VKH disease) during pregnancy. OBSERVATIONS: In the second trimester (14-27 weeks) of 1 patient, inflammation was mild and could be treated by topical corticosteroid. There is the possibility that her immune response had been modified by pregnancy. Systemic corticosteroid in a high dose was administered to the two cases in the second and third trimesters of pregnancy (28-41 weeks). The severity of inflammation in these 2 patients was similar to that in nonpregnant women. Inflammation subsided immediately without recurrence in all cases. No abnormality was found during the deliveries or in the babies. CONCLUSIONS: Treatment for VKH disease during pregnancy should be chosen according to the severity of inflammation, the stage of pregnancy, and the maternal and fetal conditions.

Adult↗

PubMedDate not supplied

The muscle fiber composition of skeletal muscle as a predictor of athletic success. An overview.

Human skeletal muscle is composed of varying percentages of fiber types. This percent composition varies widely between muscles and among individuals. The fiber composition of some skeletal muscle could be construed as being advantageous to successful performance in selected athletic event. However, this relationship is not sufficiently close to warrant the conclusion that the fiber composition of the muscle per se is the determinant of the superior performance of elite athletes. Reasonably good evidence exists to support the position that the fiber composition of a muscle is the result of a genetic endowment. Although muscle fibers are mutable, present evidence is equivocal as to whether habitual participation in given type of physical activity is responsible for high percentages of a given fiber type being present in the muscles of some athletes. Although considerable knowledge has come from the study of muscle samples obtained from sedentary individuals, athletes of a wide range of performance capacity, and individuals before and after training, a considerable gap remains for a full understanding of how the characteristics of muscle are related to performance capacity. The observation that considerable variation exists in the percent distribution of the fibers within a muscle and that athletes with a wide range of fiber populations in their muscles can be successful in the same athletic event cautions against the routine application of the biopsy technique to estimate the fiber distribution of muscles and also to use such data as a routine screening procedure for predicting athletic success. The point, as was made in an earlier paper, that the biopsy technique for studying muscle is a research tool, will probably continue to be true for the near future.

Adenosine Triphosphate↗

PubMedDate not supplied

Response of skeletal muscle to training.

Physical training induces adaptive changes in skeletal muscle. These changes are localised to the active muscle with their magnitude depending upon the nature, i.e. time and intensity, of the training regimen. The most notable changes are increased concentrations of mitochondria and glycogen. With endurance training there are major changes in metabolism in that there is a greater contribution of fat to the total metabolism during submaximal exercise. This results in a conservation of the stores of glycogen with the net result of increasing total exercise capacity. This increased use of fat during submaximal exercise appears to be more closely related to the elevations in the concentration of mitochondria in muscle than to changes in total body maximal oxygen uptake. The combination of a greater contribution of fat to the metabolism and the elevated concentration of stored glycogen are prime factors contributing to the enhanced endurance capacity after endurance training. The mechanism for the greater use of fat after endurance training is discussed. Evidence now supports the hypothesis that this is due to a tighter control over the Embden-Meyerhof pathway as a result of the greater concentration of mitochondria. The effect of heavy resistance exercise on the size and strength of skeletal muscle is discussed. Some attention is focused on the recently revived controversy concerning whether muscle enlargement is the result of a hypertrophy of pre-existing fibres or of hyperplasia. It is concluded that although there is considerable evidence to support the development of hypertrophy in response to heavy resistance exercise, the contention that a splitting of fibres occurs to produce a greater fibre number is presently poorly supported.

Adenosine Triphosphate↗