[Development of a new small caliber vascular prosthesis made of ultrafine fibers: preliminary report].
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Biomedical subjects
Publications and source records attributed to A Kitamura.
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A new vein holder for a side-to-side anastomosis between a vein graft and the coronary artery is described. The holder is consisted of two nerve hooks, and those distance is adjusted. The technique for creating the diamond anastomosis is also described.
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The structural organization of the gene coding for human hepatocyte growth factor (hHGF) has been determined by seven overlapping lambda phage genomic clones including three clones that were previously characterized. The gene for hHGF spans about 70 kbp of DNA and consists of 18 exons separated by 17 introns. The coding sequence of hHGF consists of multiple putative domains that are homologous to those observed in plasminogen. These regions were found as separate exons in the gene, and the exon-intron arrangement was similar to that of plasminogen. These results suggest that the genes for hHGF and plasminogen have arisen through gene duplication events from an ancestral gene. The major transcription initiation site of the hHGF gene is located 76 bp upstream of the translational start codon as judged by S1 nuclease mapping and primer extension analyses. A TATA-like element was found 33 nucleotides upstream of the transcription initiation site. Two sequence elements, an interleukin 6 response element (CTGGGA) and a potential binding site for NF-IL6 (TGAGGAAAG), are located near the transcription initiation site. These sequence elements might be involved in the regulation of HGF gene expression.
Rat fibroblast 3Y1 cells transformed by Rous sarcoma virus (RSV) or transfected with the v-src gene showed a highly constitutive v-src gene expression. Simultaneously, marked increases in the cellular level of nerve growth factor (NGF) mRNA and NGF content in the culture medium were observed. The levels of NGF mRNA and NGF secreted into the medium were correlated with the expression level of v-src mRNA gene in both transformants and control 3Y1 cells. These results suggest that v-src gene expression is relevant to regulation of NGF synthesis in rat 3Y1 fibroblasts.
The relation between dietary calcium and blood pressure was examined in 1,928 men, ages 40-69 years, from five geographic and two occupational populations in Japan. Dietary calcium intake was estimated using 24-hour dietary recall in systematic samples of participants of population-based cardiovascular surveys from 1983 to 1987. The means of daily calcium intake of the study populations ranged from 449 to 695 mg, approximately 300 mg lower than the recommended US dietary calcium intake. Linear regression analyses were used to examine the relation between dietary calcium and blood pressure within each population, controlling for age, body mass index, alcohol consumption, and sodium intake. Total calcium intake was inversely associated with the systolic blood pressure level in each population, and the pooled estimate of the regression coefficients for millimeters of mercury of blood pressure per 100-mg increase in calcium intake was -0.54 (95% confidence interval -0.89 to -0.19). The inverse association between calcium intake and diastolic blood pressure was less consistent, and the pooled estimate did not reach statistical significance (-0.10, 95% confidence interval -0.34-0.14). Inverse associations existed for both dairy and nondairy food sources of calcium when analyzed separately, and the association was significant only for dairy calcium. Although a causal relation between dietary calcium and blood pressure cannot be established, these results suggest a possible public health implication in Japan of increasing calcium intake for the prevention and control of hypertension, where average dietary calcium intake is low.
We recently reported the isolation and sequencing of cDNA for human hepatocyte growth factor (hHGF) [Miyazawa, K., Tsubouchi, H., Naka, D., Takahashi, K., Okigaki, M., Arakaki, N., Nakayama, H., Hirono, S., Sakiyama, O., Takahashi, K., Gohda, E., Daikuhara, Y. & Kitamura, N. (1989) Biochem. Biophys. Res. Commun. 163, 967-973]. In the present study, we report the sequence of another cDNA clone for a shorter form of hHGF mRNA. Comparison of the sequence with that of the hHGF cDNA revealed that the two sequences are identical in their 5' ends up to 865 nucleotides downstream from the translation-initiation site, then completely diverge from each other. By Northern blot analysis, the hHGF-related 1.5-kb mRNA, which corresponded to the newly isolated cDNA variant, was identified in human placenta. Sequence analysis of a human genomic HGF clone showed that the diverged 3'-terminal portion of the mRNA is generated by alternative RNA-processing events utilizing a specific exon. The mRNA could encode a short hHGF molecule of 290 amino acids corresponding to the N-terminal portion of hHGF which consists of 728 amino acids. In order to examine the effect of the predicted translation product on hepatocyte growth, an expression plasmid for the cDNA variant was constructed and transfected into Cos cells. Immunoblotting analysis showed that the transfected Cos cells produced a protein of about 33 kDa. The protein product did not stimulate DNA synthesis by rat hepatocytes in primary culture.
Desmoid tumors are rare, but not in patients with Gardner's syndrome. Although standard treatment is wide surgical excision, we prescribed chemotherapy for a 30-year-old woman with intra-abdominal desmoids, a complication after subtotal colectomy for the treatment of familial polyposis coli. Exploratory laparotomy revealed that the desmoids were not resectable. Chemotherapy with combinations of vincristine, azathioprine, cyclophosphamide, and prednisone was prescribed for over 3 months, and a partial regression of the tumors occurred. Two years after the initiation of the chemotherapy, complete regression of tumors was achieved with cyclophosphamide and prednisone. Surgical excision, irradiation, and chemotherapy treatments are discussed.
The relation of body fat distribution and body mass with haemoglobin A1c, blood pressure and blood lipids were examined in 874 men aged 40 to 59 not taking medication for diabetes mellitus and who worked for an urban company in Japan. Body fat distribution was measured by the waist hip circumference ratio. Body mass was estimated by Quetelet index. Haemoglobin A1c was measured from casual venous blood samples by high-pressure liquid chromatography. Measurement of haemoglobin A1c was validated by a 75 g oral glucose tolerance test conducted in a 7% sample. There was a dose-response relation between waist-hip ratio and haemoglobin A1c concentration while the relation between body mass index and haemoglobin A1c was not evident. Using linear regression to control for age, serum total cholesterol, usual alcohol consumption, cigarette smoking and body mass index, the positive association between waist-hip ratio and haemoglobin A1c remained significant (p = 0.02). This was not true for the positive association between body mass index and haemoglobin A1c (p = 0.32). Both waist-hip ratio and body mass index were positively associated with blood pressure and serum total cholesterol, and inversely associated with HDL-cholesterol. The associations of waist-hip ratio with blood pressure and blood lipids were significant after controlling for body mass index. Therefore, the waist-hip ratio is a correlate of both glucose abnormalities and known coronary risk factors in urban Japanese men even when body mass is controlled for.
The efficacy of the Stereotactic Aqua-Stream and Aspirator (SAS&A) was experimentally investigated by using hematoma models in the test tube and in gelatin. Even a solid hematoma can be crushed by the water jet and aspirated easily. The greater the positive pressure of the water jet and the negative pressure of suction, the stronger the ability to remove clots. A water jet pressure of 10-20 kg/cm2 and a suction pressure of 100-200 mm Hg were sufficient to remove experimental clots from the test vessels. When the SAS&A was operated in the brain of dogs with a water jet pressure of 20 kg/cm2 and a suction pressure of 200 mm Hg, aspirated brain tissue was less than 15 mg/min in weight, and histological brain injuries were observed only in the area less than 2 mm from the window of the probe, indicating that the procedure with the SAS&A would be relatively atraumatic. We conclude that these observations indicate that the SAS&A can be safe and extremely useful for removal of hypertensive intracerebral hematomas, even in the acute stage.
The mature portion of the TEM beta-lactamase (BLA) gene (bla) derived from pBR322 was fused with the promoter and signal region of Bacillus subtilis cellulase (BSC) gene (bsc), and the productivity was compared with that of the cloned native bsc gene, using a wild-type B. subtilis strain and a strain deficient in three proteases (i.e., extracellular serine protease, extracellular neutral protease, and the major intracellular serine protease) as hosts. The effects of the sen, sacQ, and prtR genes, carried on the same plasmids, were tested as for the productivities of BSC and BLA. The production of BSC was increased 9-fold by using the combination of the triple-protease deficient strain and the sacQ gene, compared with that by using the wild-type strain as a host, and no degradation of BSC was observed in the triple-protease deficient strain. On the other hand, though the production of the BSC-BLA fusion protein increased 2.5-fold in the triple-protease deficient strain, the BLA activity was decreased after the cell reached the stationary phase of growth, possibly due to some proteolysis. These observations show different sensitivity of secretary proteins to cellular proteases, and suggest that BLA is decomposed by remaining minor proteases.
A 64 year-old man was performed pneumoplication for his left-sided giant bulla on December 15, 1983. After five years, consciousness loss and right hemiplegia occurred. Brain CT revealed a cystic lesion with enhancement in the left occipital lobe. Brain biopsy disclosed metastatic small cell carcinoma. Lung biopsy showed the same histopathology, so primary lesion was considered to be from the site of the previous pneumoplication. Lung cancer associated with emphysematous bulla have been mostly characterized by tumor shadow or niveáu in the bulla. In this case, the postoperative infiltrating shadow of pneumoplication had made early diagnosis difficult.
To investigate the proportion by type of stroke in communities, a stroke surveillance was conducted in three rural populations between 1979 and 1987. Among 411 stroke patients aged 40 and over determined by the modified Millikan's stroke criteria, the type of stroke was analyzed using computed tomography (CT) criteria for 273 patients who were examined by CT. 1. Incidence rates of stroke determined by the modified Millikan's criteria did not vary among the three populations in all age-sex groups except for men aged 60-69. 2. The proportion of stroke patients who had CT examinations was 84-88% for men and women aged 40-69 in the three communities. 3. According to the CT criteria, the proportion by type of stroke in patients aged 40-69 in the three communities was 32% for cerebral hemorrhage, 16% for subarachnoid hemorrhage, 42% for cerebral infarction and 10% for unspecified stroke without CT abnormalities. Among the total with cerebral infarction, the proportion with cerebral infarction in penetrating artery regions, mostly lacunar infarction, was 65% and that of infarction in cortical artery regions, mostly thromboembolic infarction, was 35% for patients aged 40-69. 4. Cerebral infarction in cortical artery regions was classified further into embolic, thrombotic and unspecified types based on CT findings, the presence of embolic origin, and symptoms at the onset. The proportion of these three types of infarction were similar in patients aged 40-69. Compared with hospital-based studies in Japan, the present population-based study showed a higher proportion of cerebral infarction and infarction in penetrating artery regions. This study also indicated that the proportion of cerebral hemorrhage and infarction in penetrating artery regions was higher and that of infarction in cortical artery regions lower in Japanese than in Caucasians.
This study was conducted with the purpose of elucidating the ventilatory effect of percutaneous magnetic stimulation of the phrenic nerve and investigating the possibility of clinically utilizing this effect as the mechanism of an artificial respirator. A magnetic stimulator consisting of a flat circular coil generating strong magnetic fields up to a maximum of 1.3 Tesla was developed. Formed from 1.8 mm diameter copper wire, this coil is 40 mm in diameter, 14 mm in thickness and has an inductance of 24 microH. The appurtenant current generator can deliver more than 5000 A to the coil. The capacitor terminal voltage (Vc) of the generator was used as a parameter of the intensity of the stimulus. Ventilatory effects were assessed mainly by diaphragmatic electromyogram and by transdiaphragmatic pressure, ventilation flow and tidal volume measurements. Magnetic stimulation was applied percutaneously to a unilateral phrenic nerve in dogs as well as human subjects and also to a median nerve of the forearm in human subjects. The range of stimulatory intensity Vc necessary to obtain ventilatory effects was 400-500 V, and the tidal volume thus obtained corresponded to normal breathing at rest for both dogs and humans. No pain was felt in the vicinity of point of application of the stimulator and there were no significant adverse effects such as changes in the ECG or heart rate. These results indicated that percutaneous magnetic stimulation of the phrenic nerve could produce adequate ventilatory effects in control applications.
To investigate secular trends in prevalence and incidence of atrial fibrillation and associated factors, data from population studies of a northeast rural Japanese community, were explored. Cross-sectional studies for men and women aged 40-69 year were conducted in 1963-1966, 1972-1975 and 1984-1987. Age-adjusted prevalence rates of atrial fibrillation show no significant change in both men and women during these three periods. Over 80% of atrial fibrillation in each period showed no clinical evidence of rheumatic valvular disease, myocardial infarction, idiopathic cardiomyopathy, congenital heart disease and hyperthyroidism. Cohorts of men and women aged 40-69 year without atrial fibrillation at baseline were constructed in 1963-1966 (1,920 persons) and in 1972-1975 (2,325 persons) and followed until 1974 and 1987, respectively. In both cohorts, incidence of atrial fibrillation without these organic diseases was positively associated with hypertension related funduscopic abnormality and urine protein. Age-adjusted incidence rates of atrial fibrillation declined in both men and women between the two cohorts. This decline which was greater in hypertensives than in normotensives may in part reflect improvements in hypertension control in this community.
Twenty-two cases (34 sides) of postoperative maxillary cysts evaluated with axial and coronal computed tomograms were reviewed. Precise characteristics pertaining to the extent of maxillary sinus involvement, loculation, presence of septae, bony perforation, and associated cystic projection or extension into adjacent structures were determined. Of the 34 sides, 13 cysts involved the sinus completely. Twelve were multilocular. Thirteen exhibited incomplete septae. Perforations were most frequent in the anterolateral and medial bony walls (28 and 27, respectively); however, the 14 posterolateral wall perforations showed a higher percentage of cystic projection into adjacent structures. Ethmoid extension was seen on two sides, orbital extension on one. Nine sides showed tooth roots communicating with the cyst. The routine use of computed tomography in the evaluation of this type of cyst is proposed.
The stereotactic aqua stream and aspirator is modified from the aqua stream and aspirator for stereotactic evacuation of intracerebral hematoma. The newly designed needles were adapted to Leksell, Patil, Komai and Sugita stereotactic equipment. The new device was used in 14 cases with intracerebral hematoma. The tips of the needles were stereotactically inserted into the center of the hematoma cavities. The ratios of evacuated hematoma against hematoma content varied from 73 to 98%, averaging 87.2%. Hematomas could be satisfactorily and safely evacuated at any stage. Cerebral perfusion pressure was increased by 20 mm Hg during surgery.
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