Biomedical subjects
Publications and source records attributed to T Yamamura.
A thread holding ring, originally developed for valve replacement surgery and now commercially available, was successfully employed when performing ileoanal or coloanal anastomosis in 34 patients. The use of this instrument for ileoanal or coloanal anastomosis shortened the operation time and resulted in a decreased rate of complications related to the anastomosis.
The incidence of postoperative hyperamylasaemia was evaluated in 70 patients who underwent staged restorative proctocolectomy. On the 14th postoperative day, 27 of 70 patients after total colectomy showed hyperamylasaemia, and the serum amylase returned to normal on the 30th postoperative day. Three out of 37 after ileoanal anastomosis and 8 out of 70 after stoma closure showed elevation of serum amylase postoperatively. Total colectomy might have a possible role in the postoperative increase of serum amylase. None of these patients had any obvious clinical evidence of postoperative pancreatitis. In 7 patients showing significant elevation of serum amylase levels (over 1000 IU), this was due predominantly to the pancreatic isoenzyme. This transitory elevation of serum amylase did not seem to be altered by the administration of therapeutic agents for pancreatitis. These observations suggest that postoperative hyperamylasaemia without clinical evidence of pancreatitis is very common after total colectomy, and that postoperative hyperamylasaemia itself does not necessarily require treatment.
We report a case of malignant histiocytosis of the intestine (MHI) in which clinical and small bowel barium examination led to an initial diagnosis of Crohn's disease. The patient's symptoms and radiologic features improved dramatically with steroid therapy, and the patient remained free of severe symptoms for five years; at this stage, massive rectal bleeding occurred and segmental ileal resection was performed. Pathology findings of the resected specimen revealed nonspecific ulceration of the ileum. The correct diagnosis, MHI, became apparent six months after surgical intervention, on the appearance of multiple lymphadenopathy.
Transmural stimulation (TS; 15 V, 0.5 msec, 1-5 Hz, for 30 sec) caused a contraction in a frequency-dependent manner of the longitudinal muscle with myenteric plexus of the guinea pig ileum. Two-min premedication with human pancreatic polypeptide (HPP, 10(-8) M-10(-6) M), neuropeptide Y (NPY, 10(-8) M-10(-6) M), and peptide YY (PYY, 10(-8) M-10(-6) M) partially, by less than 35%, reduced TS (15 V, 0.5 msec, 10 Hz)-evoked contraction in a dose-dependent manner without affecting the resting tensions. Hexamethonium, phentolamine, prazocine, yohimbine, propranolol, naloxone and theophylline had no effects on the inhibitory actions of these peptides on TS-evoked contractions. TS (15 V, 0.5 msec, 10 Hz)-evoked 3H-ACh release was significantly reduced by 2-min premedication of HPP (10(-6) M), NPY (10(-6) M) and PYY (10(-6) M). The order of potency of these depressant effects on TS-evoked contraction and 3H-ACh release was PYY greater than NPY greater than HPP. It is suggested that the members of PP family have inhibitory effects on the contractile motility by depressing ACh release from myenteric plexus of the guinea pig ileum.
The effects of propofol on synaptic transmission were characterized and compared with pentobarbital in the rat hippocampal slice preparation. Hippocampal CA1 population spike after stimulation of Schaffer collaterals indicated that the postsynaptic response was primarily mediated by non-N-methyl-D-aspartate class glutamate receptors since it was abolished by the presence of 6,7-dinitroquinoxaline-2,3-dione (DNQX). Propofol and pentobarbital depressed CA1 population spike amplitude in a dose dependent fashion. Dose-response curves for population spike amplitudes were determined for propofol and pentobarbital and the concentrations producing a half-maximum response (ED(50)) were 110 microM and 160 microM for propofol and pentobarbital, respectively. By contrast, when GABA A-mediated inhibition was blocked by addition of 100 microM pictotoxin, propofol, in concentrations up to 400 microM had no significant effect on population spike amplitudes. These results suggest that propofol attenuates synaptic transmission in the central nervous system in part by enhancing GABA A-mediated inhibition and not by depressing glutamate-mediated excitation, as occurs with pentobarbital.
Hemodynamic effects of nicardipine-induced hypotension during enflurane/nitrous oxide were evaluated in 10 surgical patients. An infusion of nicardipine was titrated to maintain mean arterial pressure at 60 to 70 mmHg under enflurane 1.5 to 2.0 vol% and nitrous oxide 60 vol%. Mean arterial pressure was well controlled with the nicardipine infusion, whereas cardiac index increased with decreased systemic vascular resistance. Heart rate increased concomitantly with decreased blood pressure, which indicated that enflurane 1.5 to 2.0 vol% did not suppress baroreceptor reflex during nicardipine administration. However, rate-pressure-product was not increased by the nicardipine. Right and left ventricular systolic work indices were not increased by the nicardipine. Right ventricular ejection fraction was not also changed by the nicardipine. Although serum norepinephrine level increased during the nicardipine infusion, the values remained within physiological ranges. Our results suggest that nicardipine-induced hypotension may be safely performed during enflurane/nitrous oxide anesthesia because neither ventricular work nor myocardial oxygen demand was increased by nicardipine.
The interactions of methamphetamine (MAMP) and ethanol (EtOH) on multiple active/passive avoidance performance and neurotransmitters in different brain regions were examined. After the acquisition schedules, rats were retrained under the influence of MAMP (2 mg/kg/day, IP), EtOH (2 g/kg/day, IP), and in combination over 20 days in rats (n = 6 per group). As a function of progress of drug treatment, MAMP-EtOH mixtures disrupt the learned avoidance performance and produced severe impairment of discriminative behavior caused by enhancement of excitability induced by MAMP when compared with MAMP only. At withdrawal, MAMP-EtOH-induced impairments of performance significantly persisted, whereas MAMP-only-induced impairments slightly recovered. At the eleventh day drug withdrawal, MAMP-only-induced alterations of neurotransmitter levels at different regions were alleviated by EtOH, but these did not return to normal levels. These data provide support for the direct antagonistic and indirect additive interactions following constant daily treatment with a combination of MAMP and EtOH. EtOH may be an important factor in MAMP abuse to MAMP-induced psychosis or neurotoxicity.
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Serum lipoproteins and apolipoproteins were analyzed in 199 patients with acute myocardial infarction (CCU group), and in 211 normal healthy individuals (control group). It was shown that serum lipoprotein abnormalities, especially elevated low density lipoprotein (LDL) levels, are closely related to atherogenesis in relatively young patients and in subjects with severe coronary lesions. The frequency of apo E4 was higher and that of E2 was lower in the CCU group than in the control group. Apo E mutants, E7 and E5, were also frequent in the CCU group. Subjects with an E3/2 phenotype had reduced LDL and increased VLDL levels, and those with an E4/3 phenotype had increased LDL levels in serum. These results suggest that apo E4 is a positive risk factor and apo E2 a negative risk factor for atherosclerosis. The action of apo E isoproteins to increase or decrease serum LDL levels may be one of the mechanisms of atherosclerosis. Furthermore, the effect of apo E isoforms on serum lipoproteins was evident even in childhood. The mutant apo E binding to LDL receptors were investigated to clarify the metabolism of apo E5 and apo E7. The affinity of apo E5 was twice that of the wild form of apo E3. Apo E7, however, had a lower receptor affinity than apo E3. Therefore, the authors postulate that individuals with apo E5 have increased risk of developing hypercholesterolemia and subsequent atherosclerosis. From the binding data of apo E7, the action of apo E7 is considered similar to that of apo E2.
Post surgical cataracts induced by corticosteroids as immunosuppressive agents were investigated in recipients undergoing triple therapy with ciclosporin and the results were compared with those who had therapy without ciclosporin administration. The subjects of the triple therapy group were 54 cases with a mean age of 31.7 years. The mean observation period was 25 months. The incidence of posterior subcapsular cataract was 77.8%. 7.9% of them developed progressed cataract. Early cataractous changes were noticed within one post-operative year in half of the cases. 3 out of 22 cases that were followed up over three years showed progressed cataractous changes. The total doses of methylprednisolone during the period of the first post-transplant year in recipients with Grades I or II and over Grade III were 7.7 +/- 1.9g and 9.8 +/- 3.6g, respectively. They were significantly higher than those in the conventional therapy group. However, a 2 to 3 g reduction in the total dose of steroids during the first year had no influence on cataract occurrence.
BACKGROUND: This study included 16 patients without complications, eight patients with ulcerative colitis, and eight patients with familial adenomatous polyposis. All patients underwent colectomy, mucosal proctectomy, and ileoanal anastomosis in the jackknife position with complete removal of the rectoanal columnar mucosa above the dentate line (IAA) through the anus. METHODS: The patients were divided into two groups: eight patients with the rectal cuff about 7 cm from the dentate line, "the medium-cuff group," and eight patients who underwent resection of the rectal stump above the levator, leaving a cuff of 2 cm, "the minimum-cuff group." RESULTS: In the medium-cuff group the percent recovery of maximum resting pressure and maximum squeeze pressure 12 months after IAA were not significantly decreased, the rectoanal inhibitory reflex recovered in 87.5% of patients, and all patients regained continence. In the minimum-cuff group, however, the percent recovery for both pressures remained significantly reduced, the reflex never recovered, and only 25% of the patients were continent after 12 months (p less than 0.05). There was no significant difference in capacity or distensibility of the ileal pouch between the groups. CONCLUSIONS: These results indicate that the medium-cuff method was associated with a superior functional result compared with the minimum-cuff method in the early postoperative period and the cuff in the lower rectum connected with the visceral nerves should be preserved to achieve better bowel function in the patient undergoing IAA. The initial mucosectomy through the anus in the prone jackknife position is useful for this purpose.
Fecal bile acids (FBA) were analyzed by gas-liquid chromatography in 29 patients [17 with ulcerative colitis (UC) and 12 with adenomatosis coli (AC)] and 5 healthy volunteers. Seven UC and 9 AC patients had undergone total colectomy and J-shaped ileal pouch-anal anastomosis (JAA). The mean daily FBA output was similar for JAA and terminal ileostomy patients (approximately 370 mg/day), and was about 1.5 times that of healthy Japanese volunteers (approximately 235 mg/day). The output of unconjugated bile acids, secondary bile acids, and 7-dehydroxylated bile acid was higher in JAA patients with UC than in terminal ileostomy patients, but there were no significant differences between the groups. The total fecal bacterial count in JAA patients was 10 times that in terminal ileostomy patients but was 1/10 of that in healthy volunteers. In patients with defunctioning high ileostomy, FBA output increased markedly (maximum, 3054 mg/day), and serum cholesterol levels were also significantly lower (P less than 0.05). These results suggest that after JAA the bile acid metabolism and fecal bacterial flora undergo more normalization than after terminal ileostomy.
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This study attempted to determine the mechanism of anal canal motility after ileoanal anastomosis with the use of alpha-, beta- and muscarinic receptor agents. Forty-five patients, 19 +/- 2 months after operation (mean plus or minus S.E.M.) and 48 control volunteers were studied. Anal manometry indicated no difference in maximum resting pressure and squeeze pressure between the patients and the normal controls. Greater amplitude and less frequent anal canal slow waves were a particular characteristic during the postoperative period. Phentolamine (alpha-blocker) exhibited a stimulatory effect on anal resting tone in the normal rectum, while propranolol (beta-blocker) and atropine (muscarinic blocker) had no effect. However, alpha-, beta- and muscarinic receptors all had stimulatory effects on postoperative anal tone. The muscarinic receptor had dominant effects on the reduction in anal canal slow wave frequency after ileoanal anastomosis. Our results indicated that neorectum after ileoanal anastomosis had hybrid characteristics of both rectum and ileum. Through analysis of receptor-related motor function, we may be able to improve our understanding of dyscontinence after ileoanal anastomosis.
BACKGROUND: There has recently been increasing interest in coloanal reconstruction after proctectomy for low rectal carcinoma. We describe here our pilot experience with seven patients undergoing modified anoabdominal resection of the rectum and a colonic J-pouch anal anastomosis. METHODS: The procedure varied according to the extent of internal anal sphincter (IAS) resection (type a, partial resection of the upper IAS; type b, circumferential resection of the upper IAS; type c, partial preservation of the lower IAS; and type d, total resection of the IAS). RESULTS: None of the patients had incontinence, but preservation of the lower half of the IAS (types a and b) showed functional superiority over more extensive IAS resection (types c and d). Only patients who underwent types c and d resection needed medications to reduce stool frequency. CONCLUSIONS: Our results suggest that the lower half of the IAS has a more important role than the upper half in the control of defecation. Total resection of the IAS did not sacrifice continence, but preservation of at least the lower IAS resulted in a better quality of life. Careful patient selection is needed when considering the use of these procedures for tumors in the lowest part of the rectum.
Cellular DNA content of primary colorectal cancers was measured by flow cytometry and investigated on clinico-pathological features to elucidate the relationship between DNA ploidy patterns and outcomes. IN 144 colorectal carcinomas, DNA diploid carcinomas accounted for 23% and DNA aneuploid carcinomas for 77%. NO significant difference was observed between DNA ploidy pattern and tumor differentiation, lymph node metastasis or lympangial invasion. DNA aneuploid tumor had a tendency to invade vein and to lead to hematogenic metastasis. Patients with DNA aneuploid tumor showed a significantly poor disease-free and overall survival rate. Significantly increased incidence of hematogenic recurrence was demonstrated in the DNA aneuploid cases. These results suggest that the DNA ploidy pattern of colorectal cancers may prove to be of prognostic value.
We studied the pharmacokinetics of continuous and bolus intraportal 5-FU infusion. In continuous intraportal infusion group, 20 mg/kg of 5-FU was infused into ileocecal vein for an hour and the same dose was infused bolusly in bolus intraportal infusion group. Blood samples were collected from portal vein continuously and liver specimens were obtained continuously. The rabbits were sacrificed at 180 minutes from the start of infusion of 5-FU and small intestine was obtained. The results were as follows: A significantly higher concentration of 5-FU in the portal vein was observed in the continuous intraportal infusion group compared with the one-shot infusion group. But the elimination rate of 5-FU was more rapid after cessation of infusion in the continuous infusion group. The rate of FdUMP elimination in the liver tended to be lower in bolus intraportal infusion. The FdUMP concentration in the small intestine was higher in the continuous intraportal infusion group than in the bolus infusion group. In the continuous intraportal infusion group, the FdUMP concentration in the liver was lower than in the small intestine. This depended on the effect of the 5-FU catabolic enzyme, dihydrouracil dehydrogenase, which is contained in the liver in large quantities. The results suggest that in order to increase the FdUMP concentration in the liver with continuous intraportal 5-FU infusion, suppression of the effect of this enzyme is necessary.
Localized giant pseudopolyposis is a rare complication in patients with ulcerative colitis which progresses to a huge intramural polypoid mass. Our case described here is a 30-yr-old female with chronic ulcerative colitis who developed localized giant pseudopolyposis with unexpected infiltrating adenocarcinoma. This case is one of an unusual form of cancer presentation in ulcerative colitis, and it indicates that we should be aware of the possibility of occult adenocarcinoma inside a large pseudopolyposis with no superficial dysplasia.