Biomedical subjects
Publications and source records attributed to T Yamamura.
The authors report a case of the passage of a total colonic J-pouch "cast" per anus after anoabdominal rectal resection and colonic J-pouch-anal anastomosis. This occurred without development of cuff abscess and was not due to occlusion of the inferior mesenteric artery. This was successfully treated, with preservation of anal function, with resection of the colonic J-pouch by transanal approach.
Cardiac electrophysiological variables during thoracic epidural lidocaine (TEL) were compared with those during continuous intravenous lidocaine (IVL) infusion in 14 mongrel dogs anaesthetized with enflurane in order to investigate the combined effects of thoracic epidural anaesthesia (TEA) and enflurane anaesthesia on intracardiac conduction. Thoracic epidural lidocaine suppressed intracardiac conduction. Sinus cycle length (SCL) and Atrium-His (AH) interval increased by 9 and 11 per cent respectively (P less than 0.05), 30 min after TEL. Intravenous lidocaine did not increase either SCL or AH. The functional refractory period of the atrioventricular node increased five per cent above the control value 15 min after TEL (P less than 0.05), while it was unchanged in the IVL group. The mean plasma concentrations of lidocaine ranged from 0.48 +/- 0.07 to 1.00 +/- 0.14 micrograms.ml-1 in the TEL group and from 0.98 +/- 0.13) to 1.21 +/- 0.15 micrograms.ml-1 in the IVL group. There were no significant differences in plasma concentrations of lidocaine in both groups during the observation period. Therefore, it is concluded that the depressant effects of TEA on intracardiac conduction were caused by blocking of the sympathetic efferent activity. Caution may be advised in administering TEA when cardiac conduction is already compromised.
The direct inotropic action of seven local anesthetics: procaine, mapivacaine, lidocaine, tetracaine, chloroprocaine, bupivacaine and etidocaine were compared in isolated cat papillary muscles. All of the local anesthetics produced a dose-related depression of maximal velocity of shortening (Vmax), maximal developed force (Fm) and maximal dF/dt. The more potent local anesthetics such as bupivacaine and etidocaine depressed myocardial contractility at significantly lower concentrations than the less potent local anesthetics such as lidocaine and mepivacaine. Depression of Vmax by bupivacaine or etidocaine was three times greater than that by lidocaine and ten times greater than that by procaine. At the same concentration (10(-4) M), direct myocardial depression was demonstrated in the following order of severity: etidocaine >/= bupivacaine >> tetracaine >> chloroprocaine >/= lidocaine >> mepivacaine >> procaine.
The effects of anesthetic induction by diazepam, flunitrazepam and midazolam on cardiac performance were evaluated in 33 ASA class I surgical patients (average age was 36 years). The patients were divided according to the 3 drug groups, and the effects of each drug assessed utilizing measurements of systolic time intervals. An increase in heart rate and decrease in blood pressure was observed following flunitrazepam and midazolam induction. There was no changes in PEPI (pre-ejection period index) and LVETI (left ventricular ejection time index) by benzodiazepines induction. The PEP/LVET ratio was increased by diazepam while the DPTI (diastolic pressure time index)/TTI (tension time index) was reduced by flunitrazepam and midazolam. However, these changes in PEP/LVET and DPTI/TTI were within normal limits. These data indicate that in healthy humans the induction dose of either diazepam, flunitrazepam or midazolam does not extremely influence either PEP/LVET for cardiac performance or DPTI/TTI for cardiac oxygen balance. The results also suggest that the simultaneous use of PEP/LVET and DPTI/TTI is more informative than any single variable for the evaluation of cardiac effects of anesthetics.
We have developed a novel, portable refractometer (Noevir-Eva) for measuring transepidermal water loss (TEWL) which consists of a light emitting diode and a phototransistor. Cobalt chloride is used as an indicator of the amount of water. Filter paper, previously soaked with cobalt chloride solution and then dried, is attached to the skin with tape (3M Blenderm). Then, the monochromatic light (670 nm) which is yielded from the light-emitting diode is irradiated, reflecting on the above-mentioned filter paper, and the intensity of the reflected light is detected by a phototransistor. The amount of water evaporation from the surface of the skin is determined by the unit of reflected light intensity. The measured values by this new apparatus show a linear relationship with those of the commercially available apparatus (Evaporimeter EP-1). Accordingly, this new refractometer for the TWEL proved to be sensitive, dependable and also inexpensive.
We have investigated the change in activity of sphingomyelinase in human whole epidermis during aging. The sphingomyelinase activity gradually decreased with the aging process; that of people aged eighty decreased to one fourth of that of people aged twenty in same area. This result indicates that the lipid metabolism may be altered in the epidermis during aging.
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Synaptic mechanisms underlying ketamine anesthesia were studied using in vitro preparations of the lamprey CNS. Although lampreys are one of the most primitive vertebrates, the synaptic physiology and pharmacology are similar to those in the higher vertebrates. Axonal conduction, transmitter release from the presynaptic terminal, postsynaptic response to the putative neurotransmitters, and resting and activated membrane properties were studied in the absence and the presence of various concentrations of ketamine. Ketamine markedly reduced N-methyl-D-aspartate (NMDA)-activated responses, such as depolarizations to bath-applied NMDA and bursting rhythm during "fictive locomotion." The 50% block of the responses took place in the presence of 10-20 microM ketamine, whereas those induced by kainate and quisqualate (the other two subclasses of L-glutamate/L-aspartate agonists) were spared at concentrations higher than 600-800 microM. None of the other neuronal events tested were suppressed in the presence of still higher concentrations of ketamine. The results support the hypothesis that ketamine might exert its anesthetic effect by a pharmacologically specific interaction with the NMDA receptor.
The BE-2 lymphocyte surface protein is frequently expressed by the malignant cells of cutaneous T-cell lymphoma (CTCL) but is not detectable on the surface of normal resting peripheral blood lymphocytes. The expression of BE-2 by normal T cells can be induced by lectin stimulation. Membrane expression of BE-2 surpasses that of the membrane receptor for IL-2, another T-cell activation marker, at day 5. The peak expression of BE-2 appears at day 6-8. The appearance of BE-2 could also be demonstrated after anti-CD3 and allogeneic stimulation. Long-term T-cell clones derived from normal donors and maintained in culture with periodic stimulation were also found to express BE-2 continuously. Thus, BE-2 is a late activation marker not expressed on normal peripheral blood lymphocytes and pathologically expressed on circulating malignant cells in the disease CTCL.
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We analyzed serum lipoproteins and apolipoprotein E (apo E) from 199 patients in CCU, having ischemic heart disease, and from 211 healthy subjects. It was suggested that serum lipoprotein abnormalities, especially elevated low density lipoprotein (LDL) levels, are closely related to atherogenesis in relatively young patients and subjects with severe coronary lesions. The frequency of apo E-4 was higher and that of E-2 was lower in the CCU group than in the control group. Apo E mutants, E-7 (Glu244----Lys, Glu245----Lys) and E-5 (Glu3 (Glu3----Lys), were also frequent in the CCU group. Apo E isoproteins have higher pI in the order E-2, E-3, E-4, and we observed that LDL-cholesterol levels increased in the same order. The apo E mutants, E-5 and E-7, are also more basic than E-4. These findings suggest that basic apo Es were associated with the development of atherosclerosis. The prevalence of familial hypercholesterolemia (FH) in the CCU group was more than 10 times higher than the reported frequency of FH heterozygotes in normal population. The persistence of marked hypercholesterolemia from infancy probably makes FH patients susceptible to atherosclerosis. Based on the analysis of LDL-receptor protein synthesis, various types of mutations were observed even in phenotypically homozygous FH patients. FH homozygotes were divided into 2 groups, a receptor-negative group and a receptor-defective group. We found a great difference in the frequency of coronary heart disease depending on whether even a small number of receptors were present or not.
Nine out of 19 newborn pups from 4 litters died or euthanatized on day 10 to 17 after birth in a specific-pathogen-free beagle colony which had been established by cesarean section and bottle-feeding. Necropsy showed congestion and edema of the lungs, congestion of the liver and splenomegaly, as well as many subcapsular petechiae and wedge-shaped areas of ecchymosis on the cut surface of the kidneys. A cytopathic agent isolated from the lungs, kidneys and liver was identified as a canine herpesvirus. The bitches in the animal house were seroconverted into positive for the isolate after the outbreak of the disease. Histopathological lesions in six cases were characterized by multiple necrosis and hemorrhage in various organs. In addition, fibrinoid necrosis was seen in the arterial walls in wedge-shaped necrotic areas of the kidneys. The outbreak appeared to be temporary, since the same disease has not occurred in the colony up to the present time.
We report on the excitatory effect of gamma-aminobutyric acid, which increased after the oral administration of valproate sodium, on anal canal resting pressure in human beings, gamma-aminobutyric acid receptors. We used this drug in order to improve continence after ileoanal anastomosis. Seventeen patients (eight with ulcerative colitis and nine with adenomatosis coli) were tested after receiving ileoanal anastomosis. The placebo showed no effect, but valproate sodium could ameliorate frequent defecation and soiling and the resulting perianal skin complications. Increasing anal resting pressure was also observed during valproate sodium administration without the amplitude, frequency of peristaltic wave, or voluntary squeeze pressure being affected. These results suggest that the subchronic administration of valproate sodium may be useful in the treatment of minor incontinence after ileoanal anastomosis.
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L-Glutamate and related excitatory amino acids (EAA) are firmly established as major excitatory synaptic transmitter substances in the vertebrate central nervous system. Questions which have been addressed include: How many receptors are there for the EAAs?; What ion channels and/or 'second-messenger' systems are regulated by these receptors?; What are the roles of EAAs in higher neural functions?; Are they involved in neurological disorders? EAA receptors appear not only to mediate normal synaptic transmission along excitatory pathways but also to participate in the modification of synaptic connections during development. However, overaction of receptors can also mediate neuronal degeneration and even cell death. NMDA receptor antagonists markedly attenuate neuronal necrosis. Therefore, it appears that ischemia- and hypoglycemia-associated brain damage results not from a lack of energy substrates but rather via the mediation of NMDA receptors and 'excitotoxic' mechanisms. The action of ketamine anesthesia is closely associated with a block of the NMDA receptor. Ketamine binds to a site within the lumen of the NMDA-activated channel and can become trapped there when the channel closes. Current evidence indicated that NMDA receptor antagonists will be of value for the treatment of delayed neuronal death. NMDA receptor will lead to understanding the mechanisms underlying learning and memory, the control of neuronal excitability and neuronal death.
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During a major abdominal surgery, intraoperative manipulation may cause circulatory changes, which lead to release of granulocyte elastase. Twenty one patients were studied to elucidate the release of granulocyte elastase and the inhibitory effect of a protease inhibitor (ulinastatin) on lysosomal enzyme release during pancreas surgery. Patients were divided into 3 groups. Patients in group A served as control. Patients in group B were given ulinastatin 10,000 units.kg-1 intravenously prior to surgery. Patients in group C were given ulinastatin 5,000 units.kg-1 intravenously twice prior to surgery and 3 hours after the start of surgery. The granulocyte elastase was measured by commercially available kits, at 7 points: prior to induction of anesthesia, immediately after tracheal intubation, 30, 60, 120, 180 min after the start of surgery and 30 min after surgery. The plasma level of elastase increased markedly during the operation in group A, it did not increase in groups B and C during the operation. Thirty min after the operation, the plasma level of elastase increased markedly in group A (354 +/- 63 micrograms.l-1), and in group B (396 +/- 167 micrograms.l-1). The plasma level of elastase was restored to normal levels 30 min after the operation in group C. These results indicate that granulocyte elastase values were maintained at significantly higher levels during and after pancreas surgery, and suggest that ulinastatin inhibits the release of granulocyte elastase during pancreas surgery.
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