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Biomedical subjects

K Sakamoto

Publications and source records attributed to K Sakamoto.

At least 325 records · Page 18Linked to original sources
PubMed1997

Daunorubicin-induced smooth muscle contraction: involvement of Ca2+ entry mechanism.

The mechanisms of the smooth muscle contractile action of daunorubicin were investigated using guinea-pig aortae, and the involvement of the Ca2+ entry mechanism was compared among different smooth-muscle preparations. In the aorta, daunorubicin showed a concentration-dependent contractile action at concentrations of 10-200 microM. The contractile response to daunorubicin was completely dependent on extracellular Ca2+, but only slightly sensitive to verapamil or nifedipine. Trifluoperazine abolished the contraction by daunorubicin, but no significant effect was noted with amiloride, phentolamine, indomethacin or staurosporine. The order of potency (sensitivity) for daunorubicin-induced smooth muscle contraction was oesophagus = gall bladder = iliac artery > bronchus = aorta, while that of maximum reactivity was iliac artery = aorta > bronchus = oesophagus = gall bladder. In the portal vein, daunorubicin showed no contractile action. Although the smooth muscle contraction induced by daunorubicin was strongly dependent on extracellular Ca2+ in the aorta, iliac artery, bronchus, oesophagus and gall bladder, its sensitivity to verapamil varied among the different smooth muscle preparations, with the sensitivity being iliac artery = gall bladder > bronchus = oesophagus > aorta. These results suggest that daunorubicin has contractile action on various kinds of smooth muscle, mainly via the transplasmalemmal Ca2+ entry mechanism, but the degree of involvement of the voltage-dependent Ca2+ channel differs among the different smooth muscle preparations.

Animals↗
PubMed1997

Electron resonance studies on the influence of anionic surfactants on human skin.

BACKGROUND: When skin is exposed to chemicals, raw materials interact with the lipid structure of the stratum corneum. At least two types of disorders can be distinguished--that of alkyl chains inside one lipid bilayer and that of lipid layer arrangement. Electron spin resonance (ESR) spectroscopy of a nitroxide spin label is a valuable method in the study of biological membranes. OBJECTIVE: These experiments define the effect of anionic surfactants on the lipid bilayer of human stratum corneum. METHODS: 5-Doxyl stearic acid (5-DSA) was used as the spin label. Sodium lauryl sulfate (SLS) and sodium lauroyl-L-glutamate (SLG) were the anionic surfactants studied. ESR spectrum measurements of surfactant-treated stratum corneum were performed and order parameters calculated. RESULTS: 1% of SLS leads to an obvious change in ESR spectra--from strongly to weakly immobilized spectra. The molecular motion of spin labels (5-DSA) in SLS-treated stratum corneum is different from that of spin labels in the untreated stratum corneum. The ESR spectra suggest that SLS affects the spin label binding to the lipid membrane and causes an increase in the mobility of bilayers. On the other hand, there were minimal changes in ESR spectra of 1% of SLG-treated stratum corneum. An increase in fluidity of skin lipid bilayers suggests a decrease in the skin barrier function. CONCLUSION: ESR may provide a facile and robust method to define the subclinical irritancy potential of anionic surfactants and other materials.

Anions↗
PubMed1997

Single dose radiocurability of four murine solid tumors and a predictive assay for the curability in situ.

Correlations between radiocurability and kinetic parameters were investigated in four transplantable tumor types in WHT/Ht mice. The radiation dose to achieve 50% tumor control at 120 days after irradiation, i.e., TCD50/120, was 30 Gy for squamous cell carcinoma H, 32 Gy for squamous cell carcinoma NOS, 46 Gy for rhabdomyosarcoma KAS, and 63 Gy for fibrosarcoma YAS. The tumor cell kinetic parameters investigated were specific growth delay, volume doubling time, 125I-iododeoxyuridine (IUdR) uptake rate, and specific cell loss rate. The specific cell loss rate was defined as the ratio of cell loss rate in non-irradiated tumors to the rate in irradiated tumors, and was obtained by measuring the retention rate of radioactivity in the tumors. No correlations were found between specific growth delay, volume doubling time, 125I-IUdR uptake rate, and TCD50. However, the specific cell loss rate correlated with the TCD50. Therefore, the 125I-IUdR labeling method may be useful as an in situ predictive assay for tumor radiocurability.

Animals↗
PubMed1997

Variation from cytopathogenic biotype to non-cytopathogenic biotype is correlated with the deletion of cellular sequence from bovine viral diarrhea viruses.

Non-cytopathogenic (NCP) viruses of bovine viral diarrhea (BVD) virus were detected at a low ratio by the reverse plaque formation method from virus samples after several plaque clonings of cytopathogenic (CP) BVD viruses; NADL and Osloss strains. This phenomenon suggests that the NCP BVD viruses are produced at a low ratio during the propagation of CP BVD viruses in vitro. To investigate the differences between the parent CP BVD virus and the NCP BVD virus as a real progeny, the regions flanking the insertion of cellular mRNA in the p125 domain of NADL and Osloss strains were amplified by RT-PCR and cloned into pGEM 3Z plasmid vector, and then sequenced. Consequently, it was confirmed that sequences of cellular mRNA insertion of CP BVD viruses, NADL and Osloss strains, were completely and exactly deleted from the NCP BVD viruses which were real progeny of CP BVD viruses, NADL and Osloss strains. These results suggest that NCP BVD viruses may revert from CP biotype to NCP biotype by the deletion of cellular mRNA insertion in the viral genome of CP BVD viruses (NADL and Osloss strains).

Amino Acid Sequence↗
PubMed1997

Pancreas morphology of the striped hyena (Hyena hyena).

The pancreas of a striped hyena (Hyena hyena) was examined by the naked eyes and light microscopy. The distribution of A, B, D and PP cells in the islets of Langerhans was investigated immunohistochemically. The pancreas, located in the mesoduodenum, consisted of three lobes. It was about 420 mm in total length, about 10-30 mm in width and about 10 mm in maximum thickness. The smallest lobe was caudally separated from two cranial lobes. This characteristic lobe was named as a caudal lobe. Two pancreatic and one accessory pancreatic ducts opened into the duodenum. The pancreatic acini, secretory ducts and endocrine islets were arranged as shown in other carnivores. A cells were located in the peripheral region of the islets, whereas B cells were equally distributed in the islets. Both D and PP cells were also discerned in the islets.

Animals↗
PubMed1997

Effect of muscle length on distribution of muscle fiber conduction velocity for M. biceps brachii.

The influence of the muscle length on the distribution of muscle fiber conduction velocity (MFCV) was estimated at 3 different elbow angles (90 degrees, 120 degrees and 150 degrees) during the contraction of 30% of isometric maximum voluntary contraction (MVC). Surface electromyogram was recorded in the distal region of m. biceps brachii using a surface array electrode. MFCVs at the different locations from the end-plate to the distal tendon of the muscle were measured directly using the averaging method. MFCVs near the end-plate and the distal tendon of the muscle showed the high values, while MFCVs in the middle region between the end-plate and the distal tendon of the muscle had low values at the same elbow angles. The mean MFCVs in the middle region decreased when the muscle length increased during the contraction of 30% MVC. The middle region length changed when the elbow joint was extended from the elbow angle of 90 degrees to that of 150 degrees. Although previous studies showed the influence of muscle length on MFCV for special regions (like end-plate, tendon, and middle region), MFCV for whole regions, that is, the distribution of MFCV has not been studied for various muscle length. The MFCV for the same region in the some muscle length could not be estimated. In the study, the distribution of MFCV in various muscle length for the contraction of 30% MVC was obtained, and the model with the function including muscle length for the estimation of MFCV was presented.

Adult↗
PubMed1997

Investigation of infection routes of Helicobacter pylori in health checks of residents by random sampling.

We performed an epidemiological study to clarify the infection routes of Helicobacter pylori (HP) in residents of a certain district. We sampled 10% of adult residents comprising 7,389 males and females in a certain geographical area for our study by random sampling. Among them, the blood was drawn from 325 subjects who agreed to undergo health checks, and Helicobacter pylori antibody (anti-HPIgG) and an antibody against hepatitis A virus (anti-HAV) were measured. In addition, we conducted a questionnaire survey on all of the 325 subjects and mainly investigated the relation between the life-style and the rate of anti-HPIgG carriers. In this geographical area, the positive rate for anti-HPIgG in the subjects in their twenties was 67% (10/15), and it increased with age. The positive rate for anti-HAV in the subjects in their twenties was 17% (2/12). When we investigated the positive rate for HP antibody in 114 subjects of 57 families. The positive rate in parents whose children (20-39 years old) were also positive for anti-HPIgG was significantly higher than that whose children were negative for anti-HPIgG (p < 0.03). There was no significant relation between other life-style factors surveyed and the positive rate for anti-HPIgG. The rate of positive anti-HPIgG carriers in this geographical area was higher in the subjects in their twenties comparing to average Japanese infection rate, suggesting that this area was highly infected by HP. Infection within the family was thought to be a factor of the higher rate of HP infection in younger generations.

Adult↗
PubMed1997

[Progression of renal disease in patients with reflux nephropathy. Follow-up study].

BACKGROUND: We previously estimated the turning point of reflux nephropathy irreversibly deteriorating to end stage renal disease, mainly based on findings in renal biopsy (Eur. Urol., 26: 153-159, 1994). In this study, we aim to evaluate clinical parameters which may be closely associated with progression of reflux nephropathy to end stage renal disease. SUBJECTS AND METHODS: Ninety five patients (84 children and 11 adults; 41 men and 54 women) with renal scar and/or reflux (>/ = grade 3), mean aged 9.4 +/- 9.1 years (3 months-53 years) were followed up for 3.7 years +/- 2.7 (6 months-18 years). Vesicoureteral reflux was bilateral in 64 and unilateral in 31; primary in 85 and secondary in 10 patients. Clinical parameters including body weight, height, blood pressure, 24 hour urinary protein excretion, serum creatinine, 99m Tc-DTPA GFR and 99 m Tc-DMSA uptake were monitored over time. All patients underwent antireflux surgery (with or without other reconstructive surgery) and open renal biopsy. Three patients progressing to end stage renal disease underwent subsequent biopsy. RESULTS: Over-5 year observation period, the prevalence of new scare formation and further extension in scar was significantly higher in the group of renal functional deterioration (35%) than in the group of stable renal function (6.0%). Over the same period DMSA uptake decreased significantly (< 0.05) in the group of scar b (Smellie's classification), suggesting most kidneys of scar b eventually resulting in atrophic kidney (scar c). Proteinuria more than 100 mg/day appeared to be a critical level for predicting irreversible deterioration in renal function. Glomerular hypertrophy was closely related to the increase in urinary protein excretion and serum creatinine, contrary to the decrease in DTPA-GFR. In addition, bilateral renal scar b, glomerular hypertrophy (> 2 SD), proteinuria (> 300 mg/day), low GFR (mean: 49 ml/min), and diastolic hypertension seemed to be implicated in the genesis of ESRD. CONCLUSION: Glomerular damage due to either reflux nephropathy or dysplasia may cause proteinuria. Proteinuria of 100 mg/day was significantly (p < 0.01) associated with 2 SD of glomerular hypertrophy on histology and clinical observation (suggesting hyperfiltration). Thereafter, a rapid increase in proteinuria followed by diastolic hypertension appears be significant for predicting ESRD.

Adult↗
PubMed1997

[A case of gastric malignant lymphoma with perforation during chemotherapy].

A 54-year-old male was admitted for loss of appetite lasting for about 3 months. The patient was diagnosed as malignant lymphoma in the stomach invading directly the pancreas, spleen and transverse colon. Chemotherapy, two cycles of VEPA.M, was selected as the initial treatment. After the first cycle of chemotherapy, the patient was discharged temporarily. During the second cycle, on an ambulant basis, the patient suddenly complained of severe pain and distension in the abdomen. Through the X-ray examination of the chest, free air was demonstrated in the bilateral subphrenic spaces. The patient was diagnosed as perforation of the gastrointestinal tract. Subsequently, total gastrectomy was performed. Pathological examination revealed no malignant cells in the stomach wall. It is suggested that the perforation was caused by weakening of the stomach wall following chemotherapy.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1997

[Interstitial pneumonia in an HTLV-I carrier].

A 31-year-old woman was admitted to our hospital because of dyspnea on exertion. She had had the same symptom a few years earlier. A chest radiograph revealed ground-glass-like shadows on both sides, and the arterial PaO2 was 54 Torr when the patient was breathing room air. We first suspected hypersensitivity pneumonitis, but the dyspnea and hypoxemia did not resolve during treatment in the hospital, and returned home. She felt no obvious changes in symptoms while at home. We found no antibodies to Tricosporon cutaneum in her serum. Computed tomography of the chest revealed diffuse pan-lobular areas of high density. Bronchoalveolar lavage was done and the total cell count was 9.6 X 10(7). About three quarters (73%) of the recovered cells were lymphocytes. Examination of a transbronchial biopsy specimen showed alveolar thickening with infiltration of small mononuclear cells. No granulomas or Massons bodies were seen, and no antibodies specific to collagen-vascular disease were detected. We therefore excluded the diagnosis of hypersensitivity pneumonitis, idiopathic interstitial pneumonia and collagen-associated pneumonitis. There was no evidence of drug-induced pneumonitis. She was seropositive for HTLV-I. We suspected that this was a case of HTLV-1-associated pneumonitis.

Adult↗
PubMed1997

[Balloon-occluded ethanol ablation therapy: (BEAT) for hepatocellular carcinoma].

To obtain simultaneous embolization of feeding arteries and portal veins in the hepatocellular carcinoma, we performed a new treatment, balloon occluded ethanol ablation therapy (BEAT), in 7 patients. A Balloon catheter was inserted into the hepatic vein draining the tumor bearing segment of the liver. During occlusion of the hepatic vein by balloon catheter, an absolute ethanol-Lipiodol emulsion was injected through a microcatheter or a microballoon catheter placed in the feeding artery. There were no major side effects. Histological examination of the specimen taken from one case showed complete necrosis of the tumor and accumulation of Lipiodol within the portal veins of the surrounding tissue.

Aged↗
PubMed1997

[A case of esophageal leiomyoma found as mediastinal tumor, diagnosed with endoscopic ultrasonography].

A 20 year-old female was admitted to our department because of an abnormal shadow in chest roentgenogram on a physical check-up. The barium swallowing study revealed an oppression of the middle of the esophagus. Endoscopy, chest CT and MRI failed to distinguish submucosal tumor from mediastinal tumor. Endoscopic ultrasonography showed the mass originated from the esophagus and a diagnosis of esophageal smooth muscle tumor was obtained. The tumor was tried to resect by thoracoscopic surgery but was failed because of its shape like a tortoise shell. The tumor was resected through the right thoracotomy and the diagnosis was confirmed histopathologically.

Adult↗
PubMed1997

An investigation of stretch reflex in physiological tremor.

This paper describes a theoretical consideration on muscle stretch reflex in physiological tremor (abbreviated as tremor). In making a model, the function of rostro-caudal homonymous motoneurone pool as well as the interaction between spinal cord mechanism and supraspinal system is investigated. The known physiology of the neuromuscular oscillations is used to evaluate the responses of a set of differential equation that represents lumped system dynamics underlying the stretch reflex process of tremor. According to the model, the stretch reflex along with the mechanics of limb is behaving as a filter. With sharp resonant peaks and without the need of any external inputs, the filter selects oscillators and sustains tremulous movement. These reflex features, especially the findings of an existence of two sharp resonant centers, are particular valuable in an explanation of the two spectral peaks observed in tremor. It is demonstrated that (1) the two peaks of tremor, which vibrate at 10 Hz and 20 Hz, largely depend on the coupling lambda between spinal and supraspinal system, i.e., lambda leads to "spontaneous symmetry breaking" producing a peak doubling; (2) the two peaks are attributable to two decoupled states found in our model. The pea with 10 Hz is attributed to the state Z+ (t) describing an average state of spinal+supraspinal system, while the one with 20 Hz denotes the state Z-(t) which presents a relative movement of spinal and supraspinal system. With regarding to the nature of tremor under various conditions such as loading, fatigue, and pseudo-gravity, this paper discusses the possible connections of lambda to these experimental environments. Also, this paper argues that representation of stretch reflex by the decoupled states is more essential than other traditional representations used in approaching to tremor phenomena.

Animals↗