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Biomedical subjects

I Matsubara

Publications and source records attributed to I Matsubara.

At least 91 records · Page 5Linked to original sources
PubMed1974

Light and x-ray diffraction studies on chick skeletal muscle under controlled physiological conditions.

1. The sarcomere length (s) of ehick slow and fast muscles (anterior and posterior latissimus dorsi (ant. lat. dorsi and post. lat. dorsi)) was measured by the method of light diffraction. In resting ant. lat. dorsi, s changed from 1.76 to 2.30 mum during stretch from minimum to maximum muscle lengths in situ, and in resting post. lat. dorsi from 2.18 to 2.63 mum.2. Resting tension started to rise in ant. lat. dorsi when s exceeded 1.7-1.8 mum, but in post. lat. dorsi not until s exceeded 2.6-2.7 mum.3. X-ray diffraction patterns showed that ant. lat. dorsi contains collagen filaments; collagen reflexions were not seen in patterns obtained from post. lat. dorsi with the same exposure time.4. The relation between active tension and sarcomere length was similar for ant. and post. lat. dorsi. The maximum active tension was observed when s = 2.05-2.15 mum in ant. lat. dorsi, and when s = 2.10-2.25 mum in post. lat. dorsi.5. X-ray diffraction patterns from both muscles showed that the periodic structures of the thick and thin filaments are similar to those in frog and rabbit skeletal muscles.6. The volume of the myofilament lattice in resting ant. lat. dorsi was 3.06 (+/- 0.14) x 10(9) A(3), in resting post. lat. dorsi 2.98 (+/- 0.09) x 10(9) A(3). These values are close to that of frog skeletal muscle. The lattice volume remained constant in ant. lat. dorsi and post. lat. dorsi over the range of sarcomere lengths found in situ.7. The equatorial diffraction patterns from the ant. lat. dorsi in rigor (glycerol extracted) were different from that of the resting muscle, and suggested that a large number of cross-bridges were attached to the thin filaments during rigor. During potassium contracture, however, the diffraction pattern remained similar to that from the resting ant. lat. dorsi.

Animals↗
PubMed1972

Effect of cigarette smoking on human precapillary sphincters.

1. Capillary filtration coefficient of human calf was measured by pressure plethysmography before and after cigarette smoking, which is known to release noradrenaline from nerve terminals of sympathetic vasoconstrictors. Calf blood flow and venous pressure-volume curves of the calf were also obtained before and after smoking.2. Capillary filtration coefficient decreased by 19% when cigarette smoke was inhaled deeply at 30 s intervals for 12-15 min, indicating the closure of precapillary sphincters.3. Calf blood flow decreased by 31% after smoking, indicating that arterioles were constricted. The degree of arteriolar constriction, however, was not strong enough to lessen the capillary hydrostatic pressure, since the absorption of tissue fluid into capillary blood vessels did not occur.4. The venous system seemed little affected by cigarette smoking, since venous pressure-volume curves were unaltered.

Adult↗
PubMed1972

Transcapillary fluid movement in human calf after drinking hypertonic saline.

1. Transcapillary absorption of interstitial fluid was demonstrated with a pressure plethysmograph applied to the human calf after the ingestion of 200 ml. hypertonic (5.1%) saline. Capillary absorption began within 15 min after ingestion and lasted for about 2 hr. The maximum rate of absorption (0.019 ml./min. 100 ml. tissue) was attained 30-75 min after ingestion.2. The total amount of fluid absorbed into capillary blood vessels in the calf was 1.11 ml./100 ml. tissue. The amount of fluid thus absorbed in the whole body was estimated to be 677 ml.3. The capillary filtration coefficient (CFC) of the calf was also measured by the pressure plethysmograph. This was 0.0038 ml./min. mm Hg. 100 ml. tissue.4. The peak value of capillary absorption pressure was 5.2 mm Hg.5. The total osmotic pressure of the plasma rose by 12.6 m-osmole/kg H(2)O after ingestion. This rise was accompanied by transcapillary fluid absorption.6. The plasma protein concentration and packed cell volume were almost unchanged by ingestion, indicating that the plasma volume was unaltered.7. It was estimated that the net shift of fluid between intracellular and interstitial compartments during the period of transcapillary fluid absorption was very small.8. It is concluded that the volume of fluid moving from plasma into intestinal lumen is the same as that flowing from interstitial fluid into plasma, and that the transcapillary absorption is caused by a difference in osmotic pressure between the plasma and the interstitial fluid.

Absorption↗