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Biomedical subjects

T Akamatsu

Publications and source records attributed to T Akamatsu.

At least 145 records · Page 8Linked to original sources
PubMed1993

Genetic mapping of bfmA mutation causing fatty acid deficiency in Bacillus subtilis.

Bacillus subtilis strain 626, defective in the bfmA gene, is a derivative derivatives of B. subtilis strain 168 and requires branched short-chain carboxylic acids for growth. Branched-chain 2-keto acid decarboxylase activity and fatty acid synthesis in B. subtilis strain 626 were 14 and 7%, respectively, of their levels in strain 626-2R, a spontaneously reverted strain. These results indicate that the bfmA mutation is in either the branched-chain 2-keto acid decarboxylase gene itself or its controlling gene. Thus, primer synthesis from the 2-keto acid substrate in strain 626 is defective, causing a deficiency in fatty acid synthesis. A bfmA mutation was transferred to a suitable genetic background and analysed. The bfmA strain, CAC1, was competent and motile, and required 50 microM CaCl2 or 5 microM FeCl3 for growth on glucose minimal agar plates. The bfmA gene was mapped between glyC (320 degrees) and ctrA (325 degrees) and estimated to be at 320 degrees by protoplast fusion and PBS1 phage transduction.

Bacillus subtilis↗
PubMed1993

Protective effects of sesamin against liver damage caused by alcohol or carbon tetrachloride in rodents.

The effects of sesamin, a potent inhibitor of delta 5-desaturase in polyunsaturated fatty acid biosynthesis, on the fatty acid compositions of tissue lipids and liver functions were examined in rodents. When a mixture of sesamin and episesamin (51.1:48.2, w/w) was given to rats at a dietary level of 0.5% for 13 days, the proportions of dihomo-gamma-linolenic acid significantly increased not only in the liver but also in plasma and hemocytes, suggesting an interference with delta 5-desaturation by these lignans. The sesamin preparation at the dietary level of 1% improved changes in various blood parameters of the mouse, such as aspartate aminotransferase and alanine aminotransferase activities, and the concentrations of total cholesterol, triglyceride and total bilirubin, caused by continuous inhalation of ethanol. In addition, sesamin showed a significant protective effect against the accumulation of fat droplets and vacuolar degeneration in the mouse liver, as confirmed on histological examination. Sesamin, at the level of 100 mg/kg body weight, also tended to prevent liver lipid accumulation by carbon tetrachloride in mice. These results indicate that sesamin and a related lignan compound have an ability to improve liver function.

Administration, Inhalation↗
PubMed1993

[New criteria for evaluating the findings of clinical laboratory tests. New reference values for ascertaining biological effects of various environmental factors].

In this article new reference values and methodology of clinical laboratory tests useful as guidelines for providing health instruction on health effects of various environmental factors are suggested. Two different processes are developed as the methods for determining the reference values, which are comprised of three elements. One of the processes is based solely on the analysis of the relationship between a certain environmental factor and the result of a certain laboratory test (Unifactor method). The other process includes also analysis of other confounding factors in addition to analysis by the unifactor method (Multifactor method). Basic to these statistical analyses is the comparison of distribution of pertinent data among individuals with and without the factor. Using one of the reference values, 'X1 (unifactor method) or x1 (multifactor method)', we can discriminate those individuals who will be affected by an environmental factor with the highest reliability. Another reference value, 'X2 (unifactor method) or x2 (multifactor method)', on the other hand, can be used to identify those individuals in whose case the health effect of the factor must be closely considered. In some cases, a third reference value, 'X0 (unifactor method) or x0 (multifactor method), can also be determined. This value corresponds to the lowest or highest limit of the range that would not be associated with the factor. We believe that many health promotion activities may become more effective through the utilization of the results of health examinations that include assessment of total and environmental factors.

Clinical Laboratory Techniques↗
PubMed1993

Long-term survival of a patient with bile duct carcinoma by endoscopic biliary drainage.

An 80-yr-old female presented with obstructive jaundice. Endoscopic retrograde cholangiopancreatography showed a carcinoma in the middle extrahepatic bile duct, and a biliary endoprosthesis was inserted. Exfoliative cytology of the bile and forceps biopsy of the tumor revealed a papillary adenocarcinoma. Surgical resection could not be done because of her cardiovascular complications, and neither chemotherapy nor radiotherapy was administered. Stents were exchanged and cleaned 21 times because of occlusion and cholangitis. Subsequent serial cholangiogram showed a slow growth of the papillary tumor, but local invasion to the adjacent organs or distant metastasis was not observed. The patient survived for 7 yr and 6 months after insertion of the biliary endoprosthesis.

Adenocarcinoma, Papillary↗
PubMed1993

Efficacy of acellular pertussis vaccine in young infants.

A prospective study of a pertussis outbreak in a residential facility was done. Among 19 residents aged < or = 2 years, 10 children were unimmunized and 9 were immunized with acellular pertussis vaccines. Of the 10 unimmunized children, 7 acquired laboratory-confirmed pertussis (four-fold titer rise, positive culture, or both); of these, 6 developed typical symptoms. Eight of the 9 immunized children acquired laboratory-confirmed infections, and 1 of these developed typical symptoms. No difference in infection was noted between the unimmunized and immunized groups (7/10 vs. 8/9, respectively), but a significant difference was observed in the development of symptoms (6/10 vs. 1/9, P < .05). Also, the isolation rate of Bordetella pertussis seemed to differ between the two groups (6/10 vs. 2/9, P = .12). In this population, acellular pertussis vaccine did not prevent infection with B. pertussis but protected most young infants from the onset of clinical symptoms.

Antibodies, Bacterial↗
PubMed1992

Mucin histochemistry of pancreatic duct cell carcinoma, with special reference to organoid differentiation simulating gastric pyloric mucosa.

The present study was undertaken to explore mucins produced in normal, metaplastic, and hyperplastic ductal epithelia as well as in carcinoma tissues of the pancreas, and used a battery of histochemical techniques. Thirty-five cases of ordinary pancreatic duct cell carcinoma and nine cases of duct cell carcinoma, which fulfilled the clinical criteria of "mucin-producing carcinoma of the pancreas," were examined. The results indicated that all lesions of mucinous metaplasia with or without papillary hyperplasia as well as atypical hyperplasia characteristically had gastric mucins and showed organoid differentiation simulating the gastric pyloric mucosa, but never stained for 8-O-acetyl-N-acetylneuraminic acid, which is a histochemical marker of the large intestine. Ordinary duct cell carcinoma also contained gastric mucins and small intestinal mucins and showed organoid differentiation, but rarely had 8-O-acetyl-N-acetylneuraminic acid. Mucin-producing carcinomas were classified into two groups: the ordinary duct cell carcinoma group and a group that showed marked atrophy and extensive fibrosis of the parenchyma, a lack of organoid differentiation and gastric mucins, and an abundance of large and small intestinal mucins. These results suggest that gastrointestinal mucins are useful markers to detect cancer-related lesions and cancers of the pancreas.

Adult↗
PubMed1992

Centrifugal blood pump with a magnetically suspended impeller.

A centrifugal blood pump with a magnetically suspended impeller has been developed. It has a single inlet and outlet, and it generates centrifugal forces by the rotating impeller. The fluid-dynamical design for inflow and outflow through the impeller leads to elimination of the axial force and unbalanced radial force acting on the impeller. Consequently, three-component control systems, instead of five-component ones, are enough to position the impeller. The magnetically suspended impeller rotates by the magnetic coupling with the permanent magnets embedded in the outer rotator of the motor. This pump has enough performance to function as a blood pump. Further research on the null-power magnetic suspension and the generation of an efficient rotating magnetic field is in progress.

Equipment Design↗
PubMed1992

Menopause related changes of adrenocortical steroid production.

To elucidate changes of adrenocortical steroid production with age, reproductive age (n = 14), peri-menopausal (n = 12) and post-menopausal (n = 13) women were studied using basal hormone levels and the results of a rapid ACTH stimulation test. Peripheral serum levels of pregnenolone, 17 alpha-hydroxypregnenolone, 17 alpha-hydroxyprogesterone, dehydroepiandrosterone and androstenedione were measured by RIA. The basal levels of all steroids except pregnenolone decreased with age. A significant increase in the levels of all steroids after ACTH stimulation was observed in all subjects. Although, there was an age related decrease in the response of C19-steroids to ACTH, the response of pregnenolone and 17 alpha-hydroxyprogesterone to ACTH did not alter with age. The preserved response of 17 alpha-hydroxyprogesterone to ACTH in post-menopausal women suggests that 17 alpha-hydroxyprogesterone production plays a role in the age independency of cortisol. In the present paper, the changes in the capacity of the post-menopausal adrenal cortex to produce androgens and C21-steroids were demonstrated.

17-alpha-Hydroxypregnenolone↗
PubMed1992

Al-type generalized amyloidosis showing a solitary duodenal tumor.

An amyloid tumor of the duodenum is a rare occurrence. A patient who presented with epigastric discomfort, in whom a barium meal study revealed a tumor of the duodenum is described. Upper gastrointestinal endoscopy showed a submucosal location of the tumor, and examination of a biopsy revealed amyloid deposition of the AL type. Diffuse tumor involvement of adjacent tissues of the duodenum and also deposits of amyloid fibrils in the liver and skin with no evidence of a chronic pre- existing disease in the patient led to the diagnosis of primary systemic amyloidosis. The distinguishing feature of this case was the formation of a solitary and relatively large tumor in the duodenum mimicking a submucosal tumor, which is in contrast to most reported cases of multiple and smaller amyloid tumors in other parts of the gastrointestinal tract.

Amyloidosis↗
PubMed1992

In vitro closing behavior of the St. Jude Medical heart valve in the pulmonary position. Valve incompetence originating in the prosthesis itself.

We examined the in vitro closing behavior of the St. Jude Medical heart valve, simulating (1) a low-pressure system, (2) the anatomic peculiarity of the right ventricular outflow tract and the main pulmonary artery, and (3) disturbed diastolic compliance of the right ventricle. The variables in the experiment were the load impedance to the pump and the valve orientation. The results were as follows. The sequence of closure of the two semidiscs was based on the valve orientation; reduction in impedance caused the semidisc that closed last to remain open, while the other semidisc continued its open-close motion; further reduction in impedance prevented the semidisc, which continued its open-close motion, from closing completely. These results highlight the forces involved in semidisc closure and the existence of a threshold of force for completion of semidisc closure. Further, the results demonstrate that under certain circumstances the threshold cannot be exceeded via those forces. Therefore this incompetence must originate in the prosthesis itself. In this regard, we suggest an urgent need to reconsider the indications for St. Jude Medical heart valve pulmonic implantation. Finally, we advocate the necessity for an in vitro assessment of valve prostheses in a low-pressure system, to evaluate the safety of right-sided placement.

Evaluation Studies as Topic↗
PubMed1992

[Changes in steroid enzyme activities with age in human ovary].

It is well documented that sex hormone secretion decreases as age advances. In this study, 17 alpha-hydroxylase (17hy), 20 alpha(beta)-hydroxy steroid dehydrogenase (20-HSD), C17-20 lyase, 17 beta-hydroxy steroid dehydrogenase (17 beta-HSD) and aromatase activities in ovarian tissues were examined in order to study the changes in steroid metabolism in human ovary with age. Tissues were obtained from women aged 30-81 years who had undergone gynecological laparotomy. Enzyme activities were measured by the conversion of 14C-labeled progesterone, 17 alpha-hydroxy progesterone and androstenedione to amounts of corresponding labeled products. Remarkable reduction of C17-20 lyase and 17hy activities were noticed in the ovaries obtained from the women in the premenopausal stage when the activities were compared with those from reproduct women. However, the activities of aromatase, 17 beta-HSD and 20-HSD were not changed. Further, a decrease of 17hy activities was observed in the ovaries obtained from menopausal women. Aromatase activity was also reduced at this stage while the 17 beta-HSD and 20-HSD remained unchanged. In addition, the formation of 17 alpha, 20 beta-OH-P4 from 17P4 was first demonstrated indicating that activity of 20 beta-HSD in postmenopausal ovary and found to be localized in the microsomal fraction. These result indicated that the changes of ovarian steroid enzyme activities with age were characterized by a striking reduction in C17-20 lyase and 17hy activities while 17 beta-HSD and 20-HSD activities were not impaired. Aromatase activity was found to be decreased in ovaries at menopause.

17-Hydroxysteroid Dehydrogenases↗
PubMed1991

Adenocarcinoma of the cervical oesophagus arising from ectopic gastric mucosa. The histochemical determination of its origin.

A case of adenocarcinoma of the cervical oesophagus was examined by employing a battery of histochemical techniques and was demonstrated to arise from ectopic gastric mucosa. The patient was a 66-year-old Japanese male. Endoscopy revealed an ulcerated tumour on the right anterior wall of the cervical oesophagus, approximately 16 cm from the incisor teeth. Pathological examination of surgically removed specimens showed well-differentiated tubular adenocarcinoma. Ectopic gastric mucosa was found in the oesophageal mucosa adjoining the carcinoma. Histochemical stains for characterizing mucosubstances and immunostains for various antigens were used. In addition to this carcinoma, ectopic gastric mucosa in the oesophagus and normal oesophageal, cardiac, tracheal and bronchial mucosa were also examined. The results showed that the carcinoma contained mucins, which showed reactivities characteristic of the gastric surface mucous cell (galactose oxidase-cold thionin Schiff reactive) and gland mucous cell (paradoxical concanavalin A staining reactive). Ectopic gastric mucosa consistently contained these mucins, but other tissue sites lacked them.

Adenocarcinoma↗
PubMed1991

Effect of alcohol on blood levels of branched-chain alpha-keto acids in male Wistar rats.

The effect of oral alcohol administration on branched-chain alpha-keto acids was studied in Wistar rats. Rats were divided into alcohol loading groups 1 (ethanol single daily dose: 2.5 g/kg body wt for 14 days) and 2 (ethanol dose: 5 g/kg body wt), and a pair-fed control group (isocaloric glucose and food equal to the amount taken by group 1 the previous day). Branched-chain alpha-keto acids, other alpha-keto acids and amino acids were analysed using high-performance liquid chromatography. Results showed a significant body weight increase in the alcohol loading groups. Concentrations of branched-chain amino acids and keto acids were significantly increased in the alcohol-treated groups. The blood levels of methionine, threonine, alanine and glutamic acid were also increased by alcohol administration. Blood levels of taurine and ornithine, however, showed a significant decrease in the alcohol-treated groups. These results show that alcohol increases the blood levels of branched-chain keto acids and branched-chain amino acids.

Alcohol Drinking↗
PubMed1991

[Relations of serum apolipoprotein A-I, A-II and B levels to smoking, drinking and body mass].

To examine whether the serum apolipoprotein A-I level (Apo A-I), serum apolipoprotein A-II level (Apo A-II) and serum apolipoprotein B level (Apo B) are related to cigarette-smoking habits, drinking frequency and body mass index (BMI) independent of serum lipoprotein cholesterol levels (HDLC, LDLC or VLDLC), we statistically analyzed the data on Apo A-I, Apo A-II, Apo B, HDLC, LDLC and VLDLC and the life style data obtained from health examinations of 256 male residents aged 40 to 49 mostly randomly selected from two Japanese areas, Ninohe, Iwate and Ishikawa, Okinawa. The results were as follows: (1) HDLC was strongly positively correlated with Apo A-I and Apo A-II, while Apo B was strongly correlated with LDLC and VLDLC. (2) According to univariate analyses, Apo A-I, Apo A-II, Apo B, HDLC, LDLC and VLDLC were not associated with smoking. On the other hand, drinking frequency was positively associated with Apo A-I, Apo A-II and HDLC. Apo A-I and HDLC were negatively correlated with BMI, whereas Apo B, LDLC and VLDLC were positively correlated with BMI. (3) According to the results of multi-dimensional analyses of covariance, Apo A-II was positively correlated with drinking frequency independent of Apo A-I and HDLC, especially among the individuals with increased HDLC. The same multivariate analysis showed that Apo B was positively associated with smoking independent of LDLC and VLDLC among the individuals without increased VLDLC. From these results, we conclude that Apo A-II may be effective as a biological marker for alcohol drinking independent of Apo A-I and HDLC, while cigarette smoking may affect Apo B through a certain direct mechanical effect. (4) Increased HDLC in obese individuals (BMI greater than or equal to 27) or non-drinkers was associated with remarkably increased Apo A-I, while decreased HDLC in thin individuals (BMI less than 21) was associated with remarkably decreased Apo A-II.

Adult↗
PubMed1991

Epidemiology of glaucoma in Japan--a nationwide glaucoma survey.

A population-based, collaborative glaucoma survey was conducted in seven regions throughout Japan, during the years of 1988 and 1989. The total number of subjects examined was 8,126 out of 16,078 residents aged 40 years or older, representing a participation rate of 50.54%. There were no significant differences in background factors between participants and randomly sampled nonparticipants. A mainstay of the screening consisted of tonometry and fundus photography with nonmydriatic camera, followed by automatic perimetry as a recall examination. Overall prevalences obtained were primary open-angle glaucoma (POAG) 0.58%, low-tension glaucoma (LTG) 2.04%, primary angle closure glaucoma (PACG) 0.34%, other types of glaucomas 0.60%, and ocular hypertension (OH) 1.37% at the time of screening. The very high prevalence of LTG and extremely low prevalence of OH in the Japanese might reflect a racial peculiarity in the age-specific trend of the intraocular pressure. The prevalence of PACG was found much higher in Japanese than in Caucasians, with a predilection for women. Racial peculiarities as revealed in this study were discussed, with particular reference to the refractive status in the Japanese that showed progressive decrease in myopia with age.

Adult↗
PubMed1991

Factors affecting the patency of stents in malignant biliary obstructive disease: univariate and multivariate analysis.

To investigate the factors affecting the patency of biliary stents, we performed univariate and multivariate analyses in 370 straight stents with diameters of 10- to 12-French gauge which had been inserted singly as palliative treatment in 228 patients with malignant biliary obstructive disease. In the analysis of 226 first stents, advanced age of patients and higher serum bilirubin levels before insertion were found to be significant unfavorable factors limiting the duration of stent function. Overall, older age, male sex, no stent cleaning, and insertion on three or more occasions were significant unfavorable prognostic factors for patency. The risk of occlusion for stents inserted on three or more occasions was 2.32 times that of the first stent insertion. The median duration of patency of first, second, and subsequent stents was 177, 98, and 97 days, respectively. Diagnosis and the area of stenosis were unrelated to patency. No predictive significance of length or size of stent between 10- and 12-French gauge was found in our study.

Actuarial Analysis↗
PubMed1990

Histochemical demonstration of mucins in the intramucosal laminated structure of human gastric signet ring cell carcinoma and its relation to submucosal invasion.

Thirty-one cases of signet ring cell carcinoma of the human stomach at an early stage were studied, employing a variety of histochemical techniques to characterize mucins and to elucidate factors accelerating the invasion of carcinoma beyond the muscularis mucosae. Signet ring cells were classified into six types largely depending on their histochemical reactivities. In 29 of 31 cases examined, the histochemical stainings detected the presence of characteristic mucins in an intramucosal laminated structure of proliferating carcinoma cells. The upper and lower layers of the typical intramucosal laminated structure consisted of carcinoma cells containing surface mucous cell and glandular epithelial cell-type mucins respectively, whereas the middle layer was occupied by immature carcinoma cells. Such a structure appeared to simulate cellular differentiations occurring in normal mucosa. The intramucosal laminated structure underwent structural distortion or disappeared, where submucosal invasion was evident. Ulceration appears to trigger the invasion beyond the muscularis mucosae.

Adenocarcinoma, Mucinous↗