Biomedical subjects

J Hashimoto

Publications and source records attributed to J Hashimoto.

At least 163 records · Page 9Linked to original sources

PubMed1990

[Development of a converging collimator for thyroid scintigraphy].

Thyroid scintigraphy is generally performed using a pin-hole or a parallel-hole collimator. The former yields a high resolution image, however, the acquisition time prolongs because the collimation system magnifies a thyroid image. The latter has somewhat low resolution, because the collimation system cannot magnify the thyroid image and it is difficult to close the collimator surface to a patient thyroid. The defects of the above two collimators are distortion or blurs at the thyroid edge of the acquired image. To improve the image quality of the thyroid scintigram, we made computer simulations concerning contrast resolution in comparison of a parallel-hole, pin-hole and converging collimator. The simulations results showed that the contrast resolution by the converging collimator is superior to the other collimators. According to the results, we developed a specially-designed converging collimator (thickness: 100 mm, focal length: 195 mm). We cut an edge of the collimator to decrease the distance between the neck and the collimator surface. Under almost the same conditions for spatial resolution and sensitivity, we compared the effectiveness of the converging collimator with that of the other two collimators; the pin-hole type [medium resolution] and the parallel-hole type [high resolution]. As a result of experiments using a phantom, the converging collimator showed less distortion compared with the other collimators at the deep area of the thyroid phantom.(ABSTRACT TRUNCATED AT 250 WORDS)

Computer Simulation↗

PubMed1989

A novel nonpeptidic, orally active renin inhibitor.

BW-175 is a newly synthesized renin inhibitor which is a nonpeptidic, norleucine analog. Its IC50 values for renin activity in human, squirrel monkey, marmoset, dog, hog, rabbit and rat plasma were 3.3, 6.6, 2.4, 42, 110, 86 and 3500 nM, respectively, and 26 microM for cathepsin D. Pepsin and angiotensin converting enzyme were hardly inhibited at 10(-4) M. BW-175 showed an oral bioavailability of 2.8% at 10 mg/kg and 9.7% at 30 mg/kg in rats. In normotensive, furosemide-treated high-renin marmosets, BW-175 (30 mg/kg p.o.) caused an intensive reduction in plasma renin activity and plasma angiotensin I formation, associated with a reduction in systolic blood pressure of 10-20 mm Hg for 2 hours.

Aminocaproates↗

PubMed1989

Effect of disopyramide on initiation of atrial fibrillation and relation to effective refractory period.

Electrophysiologic studies were performed before and after intravenous administration of disopyramide (2 mg/kg) to 40 patients with either documented or suspected atrial fibrillation (AF). In control studies, sustained AF (greater than 1 minute), nonsustained AF (1 to 60 seconds) and no AF were found in 14, 18 and 8 patients, respectively. After disopyramide, the ability to initiate AF was totally lost in 18 patients (group A), while 22 patients (group B) showed sustained AF (11 patients) or nonsustained AF (11 patients). The effective refractory period of the atrium was 232 +/- 41 ms in the control study and 266 +/- 49 ms after disopyramide. Atrial functional refractory periods before and after disopyramide were 282 +/- 43 and 317 +/- 48 ms, respectively. The differences and ratios of the refractory periods after and before disopyramide were higher in group A than in group B (p less than 0.001). The prolongation of atrial refractoriness after disopyramide was important to suppress the initiation of AF in group A. In some group B patients, on the other hand, the initiation of AF was promoted after disopyramide. Disopyramide may alter the atrial electrophysiologic substrate required for AF initiation.

Atrial Fibrillation↗

PubMed1989

In-vitro contractility of human seminiferous tubules in response to testosterone, dihydrotestosterone and estradiol.

The effects of steroids (testosterone, dihydrotestosterone and estradiol) on human seminiferous tubules in vitro were ascertained by recording the intratubular pressure with a servonull micropressure measuring device. We describe here the first response of the human seminiferous tubule to steroids. Testosterone and dihydrotestosterone had a biphasic effect on tubular contractility. Higher doses of both testosterone and dihydrotestosterone induced contractions of the seminiferous tubules whereas lower doses of these compounds induced relaxation. Estradiol (10(-9) M to 10(-6) M) induced relaxation of the seminiferous tubules in a dose-dependent manner. The results from these experiments suggested that steroids may be involved in the control of contraction of the human seminiferous tubule and may regulate the movement of spermatozoa from the testes.

Adult↗

PubMed1989

Constitutive production of interleukin 6/B cell stimulatory factor-2 from inflammatory synovium.

Interleukin 6 (IL-6) production from synovial tissues of various diseases was examined. Augmented IL-6 production was found in inflammatory synovium not only in RA but also in other kinds of synovitis, including psoriatic arthritis and Behçet's disease. Increased amounts of IL-6-mRNA were detected in rheumatoid synovium using a dot blot hydridization technique. Furthermore, there was a positive correlation between IL-6 production and accumulation of plasma cells in the synovium. These findings suggest that IL-6 plays an important role not only in immune response but also in active inflammation in various kinds of synovitis.

Adult↗

PubMed1989

Inhibitory effects of tumor necrosis factor alpha on fracture healing in rats.

Fracture healing, which involves a cascade of biological tissue responses, may be affected by various biochemical substances. One of these substances is tumor necrosis factor alpha (TNF). Studies were made on the effects of TNF on healing of fractured ribs of rats. Fracture healing was inhibited by daily administration of recombinant human TNF (400 micrograms/kg body weight per day, intraperitoneally) after fracture. The rate of union on day 20 was significantly lower in the TNF-treated group (4/18, 22.2%) than in the control group (14/18, 77.8%) (p less than 0.001 by Chi-square test). Histological examination showed that TNF inhibited cartilagenous callus formation. On day 10, cartilage was seen in the gap zone and under the periosteum in the control group, but no cartilage formation was observed in the gap zone in 9 of 12 specimens from the TNF-treated group. On day 20, the fracture ends were united by newly formed bone in the control group, but mature fibrous tissue was seen in the gap zone, and bony or cartilagenous union was not achieved in the TNF-treated group. These results show that TNF inhibits cartilage formation in the early phase of bone induction in fracture healing and suggest that this effect of TNF is due to its inhibition of differentiation of mesenchymal cells into chondroblasts.

Animals↗

PubMed1989

Clinical evaluation of semiautomatic and automatic devices for home blood pressure measurement: comparison between cuff-oscillometric and microphone methods.

The accuracy and reliability of blood pressure (BP) values were evaluated by comparing values obtained with eight automatic or semiautomatic devices designed for home BP measurement (four microphone devices based on the Korotkoff-sound technique and four cuff-oscillometric devices) with those obtained by the auscultatory method, using a standard mercury sphygmomanometer. Systolic blood pressure (SBP) values obtained using the microphone devices coincided well with those obtained by the auscultatory method. However, these devices produced a certain proportion of errors in the measurement of diastolic blood pressure (DBP), sometimes resulting in recordings at least 25 mmHg higher than those obtained by the standard method. The most frequent causes of this phenomenon were an auscultatory (silent) gap and a weak Korotkoff sound after phase IV. A microphone device using a condenser microphone built into the manometer displayed comparatively good acoustic characteristics for determining DBP. All cuff-oscillometric devices demonstrated minimal mean differences and a constant s.d. of mean difference for DBP, with no great differences from the auscultatory method. However, mean differences and s.d.s in SBP measurements using cuff-oscillometric devices were relatively greater than those obtained using some of the microphone devices. Furthermore, the direction of the mean differences in measurements from those obtained with the auscultatory method differed. The error in relation to the auscultatory method tended to be reproducible in the same subjects with both the microphone and the cuff-oscillometric devices.(ABSTRACT TRUNCATED AT 250 WORDS)

Ambulatory Care↗

PubMed1989

Two distinct O-methyltransferases in aflatoxin biosynthesis.

The substances belonging to the sterigmatocystin group bear a close structural relationship to aflatoxins. When demethylsterigmatocystin (DMST) was fed to Aspergillus parasiticus NIAH-26, which endogenously produces neither aflatoxins nor precursors in YES medium, aflatoxins B1 and G1 were produced. When dihydrodemethylsterigmatocystin (DHDMST) was fed to this mutant, aflatoxins B2 and G2 were produced. Results of the cell-free experiment with S-adenosyl-[methyl-3H]methionine showed that first the C-6-OH groups of DMST and DHDMST are methylated to produce sterigmatocystin and dihydrosterigmatocystin (O-methyltransferase I) and then the C-7-OH groups are methylated to produce O-methylsterigmatocystin (OMST) and dihydro-O-methylsterigmatocystin (DHOMST) (O-methyltransferase II). However, no methyltransferase activity was observed when either OMST, DHOMST, 5,6-dimethoxysterigmatocystin, 5-methoxysterigmatocystin, or sterigmatin was incubated with the cell extract. Treatment of the cell extract with N-ethylmaleimide inhibited O-methyltransferase I activity but not that of O-methyltransferase II. Furthermore, these O-methyltransferases were different in their protein molecules and were involved in both the reactions from DMST to OMST and DHDMST to DHOMST. The reactions described in this paper were not observed when the same mold had been cultured in YEP medium.

Aflatoxins↗

PubMed1989

Similarity in amplitude of the nocturnal fall in blood pressure in old and young patients with essential hypertension.

The influence of age on the nocturnal fall in blood pressure (BP) was examined in essential hypertensive patients as well as normal subjects. BP was monitored every 5 min for 24 hr by means of a finger volume oscillometric device. Average daytime BP was similar in the 3 age groups [young: less than 40 (years), n = 49, average daytime systolic BP (ASBP) = 132 +/- 20 mmHg, average daytime diastolic BP (ADBP) = 82 +/- 17 mmHg; adult: 40 less than or equal to less than 60, n = 110, ASBP = 127 +/- 19 mmHg, ADBP = 86 +/- 13 mmHg; old: 60 less than or equal to, n = 33, ASBP = 131 +/- 17 mmHg. ADBP = 83 +/- 11, mean +/- S.D.]. The nocturnal fall in BP was observed in all age groups and its amplitude (delta BP = average daytime BP - average nighttime BP) in the old patients (delta SBP = 13 +/- 11 mmHg, delta DBP = 10 + 8 mmHg) was similar to that in the young patients (delta SBP = 11 +/- 8 mmHg, delta DBP = 10 +/- 8 mmHg). The results suggests that information on the nocturnal behavior of BP is valuable in treating aged essential hypertensives to prevent cerebral and/or myocardial ischemia during sleep.

Adolescent↗

PubMed1989

[Cytokine production in inflamed human gingival tissues--interleukin-6].

Interleukin-6 (IL-6) is involved in the final differentiation of B cells into antibody-producing cells. Recent studies reveal that IL-6 plays an important role in inflammation. Histopathological studies showed that a large number of plasma cells in periodontitis is usually seen in the apical parts of cellular infiltrates beneath the periodontal connective tissues. This evidence suggests that IL-6 may play a critical role in the development of periodontitis. Therefore, we examined IL-6 production in the gingival tissues. Twelve periodontitis patients and five gingivitis patients were included in this study. Nine individuals with healthy periodontium acted as control subjects. Biopsy specimens were dissected into fragments 3 mm in diameter and plated onto 24-well culture plates with RPMI 1640 medium. IL-6 activity in the culture supernatants was measured by IgM production assay using the cell line SKW6-CL4. IL-6 activity was detected at significantly higher levels (P less than 0.001) in culture supernatants from the gingival tissues in periodontitis (23.2 +/- 14.4 units/ml) and gingivititis (12.5 +/- 3.4 units/ml) than in control tissues (2.3 +/- 1.2 units/ml). Subsequently, the relationship between IL-6 activity and clinical stages was examined. The IL-6 levels before initial preparation (23.2 +/- 14.4 units/ml) were significantly higher (P less than 0.001) than those after initial preparation (1.4 +/- 1.8 units/ml), but were not associated with either periodontal pocket depth or the extent of alveolar bone resorption in periodontitis.(ABSTRACT TRUNCATED AT 250 WORDS)

B-Lymphocytes↗

PubMed1989

[Study of cytokine production in inflamed human gingival tissues in periodontitis. Interleukin-1 (IL-1 alpha, beta) and tumor necrosis factor (TNF alpha)].

It seems to be generally agreed that periodontal disease is a local manifestation of a systemic immune response. Interleukin-1 (IL-1), which has multiple biologic activities, is detected in the gingival sulcus fluid of periodontitis sites. Recent investigations have revealed that IL-1 and tumor necrosis factor (TNF) are analogous to osteoclast activating factor and promote bone resorption. These findings have suggested the possibility that IL-1 and TNF may play a significant role in the initiation and development of periodontal disease. However, it remains to be determined whether these cytokines influence periodontal tissue breakdown in periodontitis. To elucidate the mechanisms of tissue breakdown in periodontitis, we examined cytokine production by human periodontitis gingival tissue. Twelve periodontitis patients were included in this study. Control subjects with healthy periodontium consisted of nine individuals. Gingival samples were biopsied from inflamed or healthy gingival tissues. Biopsy specimens were dissected into fragments 3 mm in diameter and plated onto 24 well culture plates with RPMI 1640 medium. IL-1 activity was measured by a growth inhibition assay using melanoma cell line A 375. An enzyme-linked immunosorbent assay (ELIZA) was used for measuring levels of human IL-1 alpha, IL-1 beta. TNF alpha activity was measured by a growth inhibition assay using cell line LM2D6. IL-1 activity was detected in significantly (p less than 0.001) higher levels in culture supernatants from gingival tissues in periodontitis (48.0 +/- 23.3 units/ml) than in control tissues (2.3 +/- 0.6 units/ml), however, levels of IL-1 activity were not associated with periodontal pocket depth or extent of alveolar bone resorption in periodontitis.(ABSTRACT TRUNCATED AT 250 WORDS)

Bone Resorption↗

PubMed1989

[Serum and tissue concentration of tegafur and 5-FU after administration of tegafur suppository in patients with lung cancer--correcting the influence of residual blood in the tissue].

Tissue concentration of tegafur and 5-FU was studied in 25 patients with of primary lung cancer, given 2 x 750 mg of tegafur suppository daily preoperatively (total doses 3.75-9.75 g, mean 5.16 g). Furthermore, the influence of blood remaining in the tissue was corrected in the determination of tegafur and 5-FU concentration. The tegafur level in tumor tissue (9.614 +/- 5.739 micrograms/g) was significantly (p less than 0.01) low compared with those in serum and normal lung tissue (13.185 +/- 8.198 micrograms/ml, 12.954 +/- 10.048 micrograms/g). On the other hand, the 5-FU level in tumor tissue (0.124 +/- 0.208) was significantly (p less than 0.01, p less than 0.05) high compared with those in serum and normal lung tissue (0.019 +/- 0.013 micrograms/ml, 0.035 +/- 0.031 micrograms/g) and showed approximately 2.5 times more minimum effective concentration against tumor cells (0.05 micrograms/g). The results show that preoperative administration of 2 x 750 mg of tegafur suppository daily is effective for the transfer of tegafur and 5-FU to lung cancer tissue.

Adult↗

PubMed1989

[Complication related to operative procedure in lung cancer and mediastinal malignancy--report of 6 cases].

Of the patients who underwent surgical treatment for the respiratory system at our hospital over the past 9 years, 6 were postoperatively complicated with chylothorax, 1 with liquorrhea and the other one with paraplegia. Chylothorax occurred after mediastinal lymph node dissection which was carried out for the treatment of malignant tumors. In five cases, it occurred on the left side, and in the sixth case, it occurred on the right side. In 2 patients who received conservative treatment, there was no reduction in chyle outflow, and they died of cerebral infarction and sepsis. The other 4 cases were surgically treated. In 3 of them, the impaired site of the thoracic duct was confirmed by administration of Sudan III before surgery. We confirmed that early reoperation for the chylothorax after lung resection should be performed. Liquorrhea occurred from the 5th costvertebral joint which had been directly infiltrated by lung carcinoma. Fortunately, the postoperative course was uneventful, though the patient complained of dizziness and headache until 14 postoperative days. The case of paraplegia was caused by oxydized cellulose cotton that entered the epidural space via the intervertebral foramen. It was used for hemostasis in the 5th costvertebral joint. This case indicates that oxydized cellulose cotton, which swells when it absorbs water, should be carefully used for hemostasis around the nerves.

Adolescent↗

PubMed1989

[Renography and renal imaging with 123I-orthoiodohippurate; comparison with 131I-orthoiodohippurate].

Renography and renal imaging with 123I-orthoiodohippurate (OIH) were performed in 29 patients with various renal diseases, and a comparison made with 131I-OIH. In all patients, renograms and images with 123I-OIH were superior to those with 131I-OIH, because of the increased density and image excellence of 123I-OIH. In addition, dynamic images to evaluate renal blood flow, as well as high quality sequential excretion images, can be obtained with 123I-OIH. From our clinical results, 123I-OIH is expected to replace 131I-OIH in renal function studies.

Humans↗

PubMed1989

[The optimum dose of iohexol 399 in excretory urography].

A randomized clinical trial was conducted to determine the optimum does of iohexol (iodine concentration 300 mgI/ml) as a contrast agent for excretory urography in screening outpatients. Cases were divided into two groups, 30 cases in Group A receiving 0.4 ml/kg of iohexol and 29 cases in group B receiving 0.8 ml/kg. Urography was performed at intervals of 5 minutes and 10 minutes following the injection. The diagnostic effectiveness of various X-ray images including nephrograms, the pyelocaliceal system, ureter and bladder were assessed. There was a significant disparity between the two groups during pyelocaliceal urography after 5 minutes, with a fair diagnosis attainable for 73.3% of group A versus 89.6% for group B (P less than 0.05), but after 10 minutes the rates for the two groups had evened out to 93.4% for group A and 96.6% for group B. During urography of the ureter after 5 minutes, only 16.6% of the cases in group A could be easily diagnosed against 51.7% of the cases in group B (P less than 0.05). However, after 10 minutes the rate for group A was up to 56.7% while the rate for group B was 82.8% (P less than 0.1). In the ureter after 5 minutes, non-diagnosable images constituted 26.7% of group A and 10.4% of group B, while after 10 minutes this had dropped to 16.6% for group A and 0% for group B. A comprehensive study of these results suggests that for diagnostic screenings which use iohexol as a contrast agent in excretory urography, optimal results may be obtained using iohexol in amounts of between 0.4 ml/kg and 0.8 ml/kg.

Ambulatory Care↗

PubMed1989

[The result of extended thymectomy in patients with myasthenia gravis of pure ocular type].

We studied postoperative status of 14 patients with myasthenia gravis of ocular type who underwent extended thymectomy. Nine patients were in remission, three improved, and two unchanged. No patient became worse and died. The remission rates at one, three, five, and ten years after operation were 50.0%, 58.3%, 60.0%, and 80.0%. The palliation rates at one, three, five, and ten years after operation were 64.3%, 75.0%, 80.0%, and 100%. The remission rate at one year after operation in patients of ocular type was significantly (p less than 0.05) higher than that in generalized type (191 patients). The mean preoperative duration of symptoms in patients who obtained remission after surgery was 7.2 +/- 6.5 months, while mean duration was 85.6 +/- 45.8 months in those patients who could not obtain remission, indicating a significant difference (p less than 0.05) of duration of symptoms between two groups. Among 89 patients with generalized as well as ocular symptoms before extended thymectomy, 62 patients (69.7%) still complained of ocular symptoms and 48 patients (53.9%) had generalized symptoms with or without ocular symptoms in 1 to 12 years after operation. This result shows that ocular symptoms do not disappear more easily than generalized ones. We conclude that extended thymectomy should be performed even in patients with myasthenia gravis of pure ocular type.

Adult↗

PubMed1989

[Surgical treatment of pulmonary metastases from osteogenic sarcoma-significance of aggressive resection of bilateral multiple metastases and tumors invading adjacent organs].

The results of surgical treatment of pulmonary metastases from osteogenic sarcoma were analyzed. Total cases were 23 with mean age of 17.0 +/- 9.1. The number of operations were 46, and operative procedures consisted of pneumonectomy in 1, lobectomy in 3, partial resection in 37 and resection of adjacent organs in 5. The overall five-year survival rate from the first thoracotomy was 21%. This was significantly higher than prognosis of the previous cases with pulmonary metastases which were not resected (p less than 0.001). Three-year survival rate for the group with 5 or less metastases was 57%, whereas that for the group with 6 or more metastases was 0% (p less than 0.02). To assess both the number and the diameter of metastases, an index called number-size score (NS score) was introduced, which was the sum of the diameters of each metastatic lesion. The three-year survival rate for the group with NS score 6 or less was 73%, whereas that for the group with NS score 7 or more was 9% (p less than 0.001). Disease free interval, the time of operation and histological effect of chemotherapy were not significantly related with prognosis. There was no long-term survivor among the patients with resection of adjacent organs. In conclusion, an aggressive resection of pulmonary metastases from osteogenic sarcoma should be performed with intensive chemotherapy, but significance of the resection of multiple metastases more than 20 or tumors invading adjacent organs is doubtful.

Adolescent↗

PubMed1989

[Study on indication of unilateral pulmonary artery occlusion test in patients undergoing pneumonectomy].

We tried to establish an indication of unilateral pulmonary artery occlusion test (UPAO), by analyzing the preoperative data of UPAO, overall and regional pulmonary function tests, and arterial blood gas in 55 patients who were intended for pneumonectomy. Our limits of functional indication for pneumonectomy were PPA less than or equal to 25 mmHg or TPVRI less than or equal to 700 dyne.cm-5.m2. PPA correlated with the inverse of contralateral FEV1.0/BSA (FEV section 1.0) and DLCO/BSA (section DLCO), which were calculated by multiplying preoperative values by contralateral ventilation fraction. TPVRI correlated with age, the inverse of PaO2, the inverse of FEV section 1.0, and the inverse of section DLCO. Multiple regression analysis yielded the equation, TPVRI approximately p = 1120/section DLCO + 24800/PaO2 + 6.40 X Age -506. In order to make false negative zero, the values of each parameter were as follows: age greater than or equal to 55, PaO2 less than or equal to 85 mmHg, FEV section 1.0 less than or equal to 0.8 L/m2, section DLCO less than or equal to 6.0 ml/min/mmHg/m2 and TPVRI approximately p greater than or equal to 450 dyne.sec.cm-5.m2. The specificities of each parameter were 18.6%, 20.9%, 39.2%, 40.4% and 59.0%. Therefore, in order to make false positive patients least, the criteria of TPVRI approximately p greater than or equal to 450 dyne.sec.cm-5.m2 should be used.

Adult↗