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Biomedical subjects

T Yamamura

Publications and source records attributed to T Yamamura.

At least 253 records · Page 14Linked to original sources
PubMed1991

Blood pressure measurement by arterial tonometry in controlled hypotension.

A newly developed arterial tonometer enabled us to measure the blood pressure waveforms in addition to determining systolic and diastolic pressures noninvasively and continuously. Twenty-eight adult patients undergoing orthopedic surgery under controlled hypotension were studied. Systolic blood pressure was reduced to two-thirds of baseline values with an infusion of nitroglycerin during nitrous oxide/enflurane anesthesia. Intraarterial blood pressures were simultaneously measured in either the right or the left radial artery with a cannula and a Gould P23XL calibrated transducer; tonometric monitoring was performed on the contralateral radial artery using a Colin CBM-3000 instrument. The outputs of the two blood pressure measurement instruments were recorded for later data analysis. The shape of the tonometric pressure waveform was nearly identical to the waveform recorded intraarterially even during controlled hypotension. Regression analyses of 2039 paired tonometric and intraarterial blood pressure values during the hypotensive period showed good correlations (r = 0.78 for systolic, r = 0.81 for mean, and r = 0.70 for diastolic pressures). The accuracy of systolic, mean, and diastolic readings was from 4 to 7 mm Hg with negligible bias and did not differ significantly among six systolic, four mean, and four diastolic pressure groups. Our results indicate that arterial tonometry can provide accurate, reliable, and real-time monitoring of blood pressure even during controlled hypotension.

Adult↗
PubMed1991

Vipoma of the pancreas complicating ulcerative colitis.

We report a case of vipoma of the pancreas in conjunction with ulcerative colitis in a 20-yr-old woman. Twenty months after the onset of ulcerative colitis, the patient complained of watery diarrhea and was found to have an electrolyte disorder. A pancreatic tumor was detected by ultrasonography and computed tomography, along with an elevation of serum vasoactive intestinal polypeptide (VIP). The secretory diarrhea diminished dramatically, and the serum VIP level decreased into the normal range immediately after resection of the pancreatic tumor. Immunohistochemical staining revealed a pancreatic vipoma. Despite removal of the vipoma, she underwent restorative proctocolectomy and ileal J-pouch anal anastomosis 2 yr later due to progression of the ulcerative colitis. Postoperative course was uneventful, with excellent functional results. Knowledge of this rare condition accompanying ulcerative colitis may help in the management of the patient with an atypical clinical course.

Adult↗
PubMed1991

Giant hypertrophied anal papilla. Case report.

Anal papillae, polypoid lesions formed by hyperplasia of connective tissue in the vicinity of the anal columns, are usually small and asymptomatic. A rare case of giant hypertrophied anal papilla complicated by massive anal bleeding and prolapse is reported.

Anus Neoplasms↗
PubMed1991

Alcohol addiction of methamphetamine abusers in Japan.

Fifty-eight methamphetamine (MAMP) abusers were surveyed to demonstrate the types of nature of MAMP abuse. In-depth interviews using psychophysiological techniques assessed the subjects to be truthful or deceptive about their abuse histories. Research diagnostic criteria determined the subjects clinical symptoms. The results show that three factors characterize MAMP abuse: significant correlation was found between the years of abuse; the manifestation of somatic or mental disorders or both, and alcohol (Alc) addiction. MAMP abusers who were nondrinkers or light drinkers developed a tendency to dislike Alc after MAMP abuse, while there was no change in Alc consumption in heavy drinkers. The findings suggest that the combined abuse of MAMP and Alc aggravates somatic and mental disorders and that Alc plays an important role in the fatal effect of MAMP, especially from small doses. This provides support for the synergistic effects between MAMP and Alc. Coadministration of MAMP and Alc appears to produce long-acting and more complicated changes in the brain's neurotransmitter function.

Adult↗
PubMed1991

[Experimental studies on prevention of liver metastases by continuous intraportal chemotherapy].

Our experiment was designed to elucidate the efficacy of continuous intraportal chemotherapy (CIPC) for the prevention of liver metastases. Catheter was introduced into ileocecal vein of white rabbit for administration of adriamycin (ADM). VX2 cells were inoculated into portal vein to form liver metastases. Three experiments were designed as follows: 1) Immediately after inoculation of tumor cells, ADM was administered continuously for 7 days. 2) Continuous administration of ADM started on the 3rd day after inoculation of tumor cells. 3) Immediately after inoculation of tumor cells, ADM was administered by CIPC or systemically for 7 days. The same number of tumor cells were inoculated into portal vein and no treatment was given in control group. The rabbits were sacrificed on the 14th day. Number and size of liver metastases were calculated. Results were as follows: In 1) and 2), the metastases in CIPC group were significantly decreased in number and size compared with those in control group. In 3), no metastasis was observed in CIPC group, but a third of the rabbits developed metastases in systemic group. These results suggest that CIPC is effective for prevention of liver metastases and its efficacy is greater than for systemic chemotherapy.

Animals↗
PubMed1991

Stapled anastomosis for trans-sphincteric resection of the rectum.

We have found that in all patients who have undergone this procedure, normal defecation and complete continence are maintained. The surgical wound heals well and functional results have been uniformly good, even in instances in which only 1 centimeter of the rectum remains. This procedure may be useful for patients who are carefully diagnosed by preoperative transrectal ultrasonography in which the lower edge of the rectal tumor is within 8 centimeters of the anal verge, the tumors do not extend into the muscularis propria and there is no lymph node metastasis. Use of the CEEA stapling device can shorten the time of operation and is particularly beneficial for elderly patients and those who are at poor risk.

Aged↗
PubMed1991

[A retrospective study on postoperative pulmonary dysfunction as a function of the surgical injury].

Pre- and postoperative pulmonary function tests were studied retrospectively in 80 patients. They were divided into one of 5 groups: 1, surgery of the upper abdomen; 2, surgery of the lower abdomen; 3, surgery of the body surface; 4, thoracic surgery; and 5, extensive abdominal surgery. Postoperative pulmonary function tests were performed when the patients recovered to be able to sit up. The time necessary to reach this stage varied from 8 th postoperative day in groups 1, 2, and 3 to 24 postoperative day in groups 4 and 5. FRC, %FEV1.0, V25, and TV were unchanged in groups 1 and 2 postoperatively. There was a significant reduction in VC to 81.6 +/- 24.1% and 89.1 +/- 13.3% of the preoperative value in group 1 and 2, respectively. A significant decrease in TLC and a significant increase in RV were observed in group 1. The changes in pulmonary mechanics can be attributed to the muscle dysfunction during inspiratory and expiratory effort. A decrease in TLC and an increase in RV were also observed in group 2. All of the pulmonary function variables remained unchanged postoperatively in group 3. The restrictive pulmonary dysfunction with significantly reduced VC was observed in groups 4 and 5. V50 and V25 were significantly decreased in group 4. These changes could be attributed to the use of the extracorporeal circulation during cardiac surgery and the postoperative mechanical ventilation. TLC decreased significantly in groups 4 and 5, and RV increased significantly in group 5, but unchanged in group 4. The results indicate that the expiratory muscles function normally following the thoracic surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

No severe bottleneck during human evolution: evidence from two apolipoprotein C-II deficiency alleles.

The DNA sequences of a Japanese and a Venezuelan apolipoprotein (apo) C-II deficiency allele, of a normal Japanese apo C-II gene, and of a chimpanzee apo C-II gene were amplified by PCR, and their nucleotide sequences were determined on multiple clones of the PCR products. The normal Japanese sequence is identical to--and the chimpanzee sequence differs by only three nucleotides from--a previously published normal Caucasian sequence. In contrast, the two human mutant sequences each differ from the normal apo C-II gene sequence by several nucleotides, including deletions. The data suggest that both mutant alleles arose greater than 500,000 years ago. It is shown that a defective allele can persist in a population for only a short time if a bottleneck occurs. Therefore, the antiquity of the two alleles suggests no severe bottleneck during human evolution. Moreover, the fact that one allele is from Japan and the other is from a Venezuelan Caucasian family is more consistent with the multiregional evolution model of modern human origins than with the complete replacement or "out of Africa" model.

Alleles↗
PubMed1990

The spontaneously epileptic rat (SER), a zitter*tremor double mutant rat: histopathological findings in the central nervous system.

The spontaneously epileptic rat (SER), a mutant homozygous for both zitter and tremor genes, exhibits absence-like seizures and tonic convulsions without external stimulation from 7 to 8 weeks of age. Histopathological studies of the central nervous system revealed the following abnormalities. The 35-day-old SERs which exhibit body tremor, and which have never shown seizures, had marked vacuolation and hypomyelination in the brainstem and cerebellum. The vacuoles were produced by splitting of the myelin sheaths and swelling of the dendrites and were related to primary swelling of the astrocytes. The 2- to 3-month-old SERs with staggering gait and seizures showed focal axonal swelling ('torpedo') and advanced vacuolation in the granular cell layer of the cerebellum in addition to the abnormalities observed at 35 days of age. Degenerative neurons and spheroidal bodies were observed in the substantia nigra and ventral tegmental nucleus. These brain areas are known to be related to tonic convulsions in the several experimental models. The SER is believed to be a useful tool for the investigation of the relationship between the structure and function of the central nervous system in epilepsy. It is probable that the more severe changes in the cerebellum are responsible for the staggering gait.

Animals↗
PubMed1990

Enhanced binding activity of an apolipoprotein E mutant, APO E5, to LDL receptors on human fibroblasts.

We have previously demonstrated an apolipoprotein E (apo E) mutant, apo E5, associated with hyperlipidemia and atherosclerotic vascular diseases. To investigate the possible mechanism of apo E5 involvement in the development of hyperlipidemia, we have isolated the apo E isoprotein and determined its binding activity to LDL (low density lipoprotein) receptors. It was shown that the apo E5 isoprotein was two times more active for binding to LDL receptors than apo E3. The concentration of apo E, at which 50% of 125I-labeled LDL bound to the receptor was displaced, was 29 ng/ml for apo E5 and 63 ng/ml for apo E3. This result suggests that the high affinity of apo E5 to LDL receptors results in a high uptake of apo E5-containing lipoproteins by the liver and leads to a down-regulation of LDL receptors in the liver. We can postulate that individuals with apo E5 are susceptible to hypercholesterolemia and in consequence to atherosclerosis.

Apolipoproteins E↗
PubMed1990

Pathogenesis of acute cholecystitis after gastrectomy.

The increased incidence of gallbladder diseases after gastrectomy is discussed with regard to contractile motility of the gallbladder. Ultrasonographic findings and contraction of the gallbladder in response to egg yolk or caerulein were studied before and after gastrectomy at intervals ranging from 2 weeks to 6 months. Enlargement of the gallbladder with accumulation of biliary sludge and hypomotility were frequently observed within a month of operation for gastric cancer, suggesting that biliary stasis is an important contributing factor in postoperative acute cholecystitis. Within 3 months of operation, contraction had recovered to close to preoperative levels and the incidence of biliary sludge formation gradually decreased. Daily administration of an opiate antagonist, naloxone (0.8 mg), significantly improved gallbladder dyskinesia and decreased the incidence of biliary sludge formation within 1 month of gastrectomy.

Acute Disease↗
PubMed1990

Binding of Cu(II), Tb(III) and Fe(III) to chicken ovotransferrin. A kinetic study.

The kinetics of binding of Cu(II), Tb(III) and Fe(III) to ovotransferrin have been investigated using the stopped-flow technique. Rate constants for the second-order reaction, k+, were determined by monitoring the absorbance change upon formation of the metal-transferrin complex in time range of milliseconds to seconds. The N and C sites appeared to bind a particular metal ion with the same rate; thus, average formation rate constants k+ (average) were 2.4 x 10(4) M-1 s-1 and 8.3 x 10(4) M-1 s-1 for Cu(II) and Tb(III) respectively. Site preference (N site for Cu(II) and C site for Tb(III] is then mainly due to the difference in dissociation rate constant for the metals. Fe(III) binding from Fe-nitrilotriacetate complex to apo-ovotransferrin was found to be more rapid, giving an average formation rate constant k+ (average) of 5 x 10(5) M-1 s-1, which was followed by a slow increase in absorbance at 465 nm. This slow process has an apparent rate constant in the range 3 s-1 to 0.5 s-1, depending upon the degree of Fe(III) saturation. The variation in the rate of the second phase is thought to reflect the difference in the rate of a conformational change for monoferric and diferric ovotransferrins. Monoferric ovotransferrin changes its conformation more rapidly (3.4 s-1) than diferric ovotransferrin (0.52 s-1). A further absorbance decrease was observed over a period of several minutes; this could be assigned to release of NTA from the complex, as suggested by Honda et al. (1980).

Animals↗