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Biomedical subjects

Y Nakata

Publications and source records attributed to Y Nakata.

At least 19 recordsLinked to original sources
PubMed1992

Radioimmunoassay of 5 beta-cholestane-3 alpha,7 alpha,12 alpha,25-tetrol 3-glucuronide in serum of patients with cerebrotendinous xanthomatosis.

A rapid, convenient, and specific radioimmunoassay for 5 beta-cholestane-3 alpha,7 alpha,12 alpha,25-tetrol has been developed. Specific antiserum was obtained from rabbits immunized by the bile alcohol-bovine serum albumin conjugate, which was coupled by an (O-carboxymethyl)oxime bridge at the C-3 position. The assay produces values for serum concentrations of bile alcohol glucuronides in patients with cerebrotendinous xanthomatosis.

Brain Diseases↗
PubMed1992

Ossifying fibroma of the thoracolumbar spine: a case report and review of the literature.

A 43-year-old woman with ossifying fibroma of the thoracolumbar vertebrae was presented with a 6-month history of progressive radiculomyelopathy. The symptoms were successfully treated by laminectomy and partial resection of the lesion. This is the first reported case of ossifying fibroma involving the thoracolumbar spine. The clinical significance and management of this rare lesion are discussed with a review of the literature.

Adult↗
PubMed1992

Fluorescence digital image analysis of thrombin and ADP induced rise in intracellular Ca2+ concentration of single blood platelets.

Cytoplasmic free Ca2+ concentration, [Ca2+]i, was estimated in single rabbit blood platelets by digital imaging microscopy with the use of the specific Ca(2+)-indicator dye Fura-2. Uneven distribution and low level of [Ca2+]i was found in the resting platelet even in the presence of extracellular 1 mM Ca2+. Thrombin at 1 unit/ml immediately caused a transient increase in [Ca2+]i, which was followed by a secondary and sustained increase in [Ca2+]i. The distribution of increased levels of [Ca2+]i was also shown to be uneven within the cell. The presence of 1 mM EGTA in the medium only slightly decreased the initial rise in [Ca2+]i, but completely inhibited the latter phase, a sustained rise in [Ca2+]i. This result shows that the initial rise of [Ca2+]i might not be caused by Ca2+ influx, but might be induced by mobilization of Ca2+ from intracellular Ca2+ storage sites. This speculation is further supported by the fact that the elevated [Ca2+]i induced by thrombin immediately decreased to the base line value when 3 mM EGTA was applied. Thus, thrombin induced elevation of [Ca2+]i is suggested to consist of two different processes, namely the mobilization of Ca2+ from the intracellular storage sites and the successive Ca2+ influx through the receptor activated Ca2+ channels. Stimulation with ADP also caused a rapid elevation of platelet [Ca2+]i, but this effect of ADP was different form that of thrombin. Thus, the ADP induced rise in [Ca2+]i was accompanied by oscillation and was inhibited by extracellular EGTA. Our present experiment is the first report that clearly and directly reveals the differences between the effects of thrombin and ADP on [Ca2+]i of platelets.

Adenosine Diphosphate↗
PubMed1992

Chiba Spinal System in the operative management of scoliosis.

The Chiba Spinal System was developed for three-dimensional correction of scoliosis. The system consists of a 7-mm diameter smooth solid rod, closed and open hooks, and specially designed conical sleeves. The rod does not have ratchets or threads, thus minimizing stress concentrations. The closed and open hooks are attached to the rod using the conical sleeves. The sleeves have longitudinal slits permitting compression during insertion. The outrigger system with a torque wrench is used to correct the deformity in the frontal plane. When correcting lordosis with vertebral rotation, a sagittal correction device may be used. Fifty-two patients with idiopathic scoliosis were operated on with this system from 1986 through 1989. The average correction of the scoliosis was 58%. For the 21 patients with thoracic lordosis less than 0 degrees, the mean preoperative lordosis was -8 degrees, which was corrected to +7 degrees. The mean correction of the vertebral rotation was 24%. Two patients complained of paresthesia of the thoracic region after operation, but this disappeared within 2 weeks. In 32 patients with more than 2 years' follow-up, the mean loss of correction was 3 degrees. One case with instrumentation failure was noted.

Adolescent↗
PubMed1992

Case report of an insulin-dependent diabetes multiplex family with a pair of identical twins.

The following is a case of a family with a pair of identical twins and a family history of insulin-dependent diabetes mellitus (IDDM). A 2 year old identical twin was first admitted to our hospital and diagnosed as IDDM based on diabetic ketoacidosis. His father has been treated with insulin since the diagnosis of IDDM at the age of 17. All family members had the HLA-DR4 and DQA1*0301 alleles, which are strongly associated with IDDM. The DR-DQ haplotypes of the father and both twins were DR4-DQW8 (DQB1*0302), which increases susceptibility to IDDM. Islet cell antibodies were positive only in the index twin at the time of diagnosis. The co-twin was considered to have beta-cell dysfunction based on the result of an intravenous glucose tolerance test.

Adult↗
PubMed1992

VDD pacing with a previously implanted single lead system.

Three patients who had undergone implantation of a rate modulated, atrial sensitive RS4 pacemaker, with a single orthogonal lead underwent replacement of a depleted unit with a DDD pulse generator, reusing the original lead with an adapter that allowed conversion of the bipolar atrial electrode into unipolar configuration. The mean atrial electrogram amplitude was 1.8 mV and no significant atrial sensing defects were found during Holter monitoring. As the RS4 pulse generator is no longer available, continued VDD pacing is possible by replacing it with a DDD pulse generator using the previously implanted single lead system.

Aged↗
PubMed1992

Clinical significance of QRS duration during ventricular pacing.

To clarify the clinical significance of an abnormally prolonged paced QRS duration, we studied 114 patients who had undergone pacing for atrioventricular block (AVB). Patients were divided into two groups: group I consisted of 29 patients with at least one paced QRS duration greater than or equal to 180 msec during the follow-up period; group II consisted of 85 patients with paced QRS durations less than 180 msec. The clinical background, QRS complexes before pacing, and the echocardiographic findings were assessed. Males (P less than 0.05), those with H-V block (P less than 0.05) and a wider QRS complex of conducted and escape beats (both P less than 0.01) were dominant in group I. The incidence of underlying heart disease was greater in group I than in group II (83% vs 32%, P less than 0.01). Reduced left ventricular ejection fraction (LVEF) and increased left ventricular end-diastolic dimension (LVDd) were more prominent in group I than in group II (LVEF 0.49 +/- 0.17 vs 0.68 +/- 0.10, P less than 0.01, LVDd 57.1 +/- 7.9 mm vs 48.5 +/- 5.6 mm, P less than 0.01). The paced QRS duration correlated with LVEF (r = -0.61) and LVDd (r = 0.81). A paced QRS duration greater than or equal to 180 msec was sensitive and specific for a LVEF less than 0.5 (83.3% and 85.2%) and LVDd greater than or equal to 60 mm (100% and 81.4%). We conclude that patients with a prolonged paced QRS duration have more serious heart disease, and the paced QRS duration can be a useful indicator of impaired LV function.

Cardiac Pacing, Artificial↗
PubMed1992

Long-term follow-up study of three patients with the long QT syndrome.

We studied three women with the long QT syndrome. They were aged 42, 52 and 25 years and had experienced recurrent syncopal attacks. We followed case 1 for 17, case 2 for 18, and case 3 for over 6 y. The attacks tended to occur during the premenstrual stage in case 1 and case 2; case 3 often experienced attacks after exercise. The QT(U)c intervals on admission were 0.68, 0.62, and 0.50 in case 1, 2, and 3, respectively. Torsade de pointes followed by ventricular fibrillation was documented in case 1 and case 2. Although each was treated with a beta-blocker, none was fully compliant with the regimen. In case 1, estrogen therapy administered to maintain the hormonal balance premenstrually effectively prevented attacks. Despite the inconsistent use of beta-blockers, the attacks in case 1 and case 2 tended to decrease with age. Case 2 experienced no attacks after menopause. Cause 3 took medication consistently and remained free of attacks for over 6 y. Although she discontinued beta-blocker therapy because of pregnancy, she has experienced no attacks to date. These case studies suggest that hormonal status may be important in the development of syncopal attacks in female patients with the long QT syndrome.

Adult↗
PubMed1992

Isolation of substance P binding protein from rat brain.

Substance P (SP) binding protein of rat brain was solubilized by digitonin. The solubilized proteins were then purified by sequential gel filtration, concanavalin A lectin Sepharose, and SP-affinity chromatography. The calculated molecular weight of this purified SP binding protein was 76-74 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The rabbits were immunized with the purified protein and resulting polyclonal anti-sera were tested. The immune serum significantly inhibited [3H]SP binding to the 3-[(3-cholamidopropyl)dimethylammonio]-1-propane sulfonate solubilized membrane fractions from rat brain, whereas pre-bleed antiserum failed to inhibit the binding. This polyclonal antibody also inhibited the activity of 45Ca influx into astroglioma cells stimulated by SP, but does not inhibit that stimulated by histamine. Furthermore, this polyclonal antibody recognized the 76-74 kDa band as assessed by Western blotting. These data strongly suggest that this polyclonal antibody could recognize a part of the natural SP receptor site.

Animals↗
PubMed1992

Clinical features of 125 patients with sarcoidosis: Okayama University Hospital review of a recent 10-year period.

Clinical features were studied in 125 patients with sarcoidosis (72 females and 53 males) diagnosed at Okayama University Hospital during a recent 10-year period. The age distribution had two peaks in patients in their 20s and the 50s. Over half of the patients were detected at health screening check and were asymptomatic, while the remaining were symptomatic. Twelve patients were in stage 0, 41 were in stage I, 54 were in stage II, 16 were in stage III, and 2 were in stage IV according to the chest x-ray findings. Serum angiotensin converting enzyme levels and serum lysozyme levels were elevated in 60% and 76% of the patients, respectively. The bronchoalveolar lavage fluid showed lymphocytosis, especially of helper T-cells. The clinical features of sarcoidosis appear to depend on the duration of the disease.

Adolescent↗
PubMed1992

[An elderly case of hypertension with persistent orthostatic hypotension].

The authors report the successful control of labile hypertension associated with orthostatic hypotension in a 75-year-old male patient, by means of L-DOPS, a synthetic precursor of norepinephrine in combination with antihypertensive drugs. He had been known to be hypertensive for 15 years and developed a persistent floating sensation 2 years age. Despite good control of hypertension after admission, orthostatic hypotension was still observed. Passive tilt produced a blood pressure reduction of 60/20 mmHg. Spectral analysis of heart rate variability showed a disturbance in the activation of the sympathetic nervous system. Treatment with L-DOPS attenuated the blood pressure reduction in response to passive tilt (35/12 mmHg) and improved the sympathetic response. Because of an increase in blood pressure by L-DOPS, addition of either a calcium channel blocker or an angiotensin-converting enzyme inhibitor was necessary. These combinations of treatment successfully controlled blood pressure as well as orthostatic hypotension.

Aged↗
PubMed1992

Biosynthesis of cholesterol linoleate by polyethylene glycol-modified cholesterol esterase in organic solvents.

Cholesterol esterase modified with polyethylene glycol was able to dissolve in some highly hydrophobic solvents such as benzene and toluene, and catalyze the synthesis of cholesterol linoleate with time dependency in the reverse of the usual reaction in aqueous solvents. Enzymatic cholesterol linoleate synthesis followed Michaelis-Menten kinetics which depended on the concentration of cholesterol and linoleic acid. When more than 20 mM of both substrates was used, the specific activity in this esterification was 200-250 nmol/min/mg protein. The apparent Km value for cholesterol and linoleic acid was 3.7 and 7.6 mM, respectively. The possibility of using such a modified enzyme for the synthesis of less stable cholesterol esters is discussed.

Cholesterol Esters↗
PubMed1992

[Malignancies in patients with sarcoidosis].

We evaluated the occurrence and type of malignant tumors in 148 patients with sarcoidosis followed at the Okayama University Hospital. Nine patients had malignancies; in 2 of 9 patients the development of malignancy preceded that of sarcoidosis, and one patient presented with sarcoidosis and malignancy at the same time. Six patients developed six types of malignancy following the development sarcoidosis; one case each of stomach cancer, lung cancer, breast cancer, thyroid cancer, testicular tumor, laryngeal cancer, and chronic lymphocytic leukemia. There was no significant difference between sexes (3 males and 3 females). The mean age of the cancer group at the onset of sarcoidosis was 56 years, which was significantly higher (p less than 0.05) than that of the control group. In these 6 patients, the mean interval from onset of sarcoidosis to detection of cancer was 11.7 years (range 1.5 to 30.2 years). The relative risk of malignancy was calculated based on the data for 148 patients with sarcoidosis with a total of 1371 person-years. The expected incidences of cancer for all sites and specific sites were estimated by applying age- and sex-adjusted person-years. The observed incidence of cancer was significantly (p less than 0.05) greater than the expected incidence for thyroid cancer, laryngeal cancer, and leukemia. No significant difference in incidence was found for all sites or for the other sites of cancer. The increased cancer incidence in sarcoidosis may be secondary to immunological abnormalities associated with this disease.

Adult↗
PubMed1992

Enzymatic properties of polyethylene glycol-modified cholesterol esterase in organic solvents.

The solvent dependency and substrate specificity of polyethylene glycol (PEG)-modified cholesterol esterase (CEH) catalyzing cholesterol ester synthesis in organic solvents were studied. When cholesterol and linoleic acid were used as the substrates, PEG-modified CEH synthesized cholesterol linoleate only in water-immiscible organic solvents. Among some solvents capable of solubilizing all of the reaction components (PEG-modified CEH, cholesterol, and linoleic acid), chloroform was most suitable for enzymatic cholesterol linoleate synthesis, and the synthetic activity for cholesterol linoleate decreased in the order chloroform, benzene, toluene, and cyclohexane. PEG-modified CEH synthesized various cholesterol esters with significant substrate specificity. The substrate specificity for cholesterol ester synthesis in benzene was analogous to that for cholesterol ester hydrolysis in aqueous solution.

Cholesterol↗
PubMed1992

[Release of interleukin-6 by alveolar macrophages in patients with sarcoidosis].

The supernatants from cultures of alveolar macrophages from 12 patients with sarcoidosis and 7 control subjects were assayed for interleukin-6 (IL-6) using an ELISA system. IL-6 was detectable without a stimulant in supernatants from all subjects with sarcoidosis and controls. However, the supernatants from 4 of 12 untreated patients with sarcoidosis contained significantly greater amounts of IL-6. When macrophages were stimulated by Propionibacterium acnes (P. acnes), the mean level of IL-6 in the supernatant of patients with sarcoidosis was 5.18 +/- 1.46 ng/ml, which was significantly higher than in controls (3.34 +/- 0.39) (p less than 0.05). Furthermore, in patients with sarcoidosis, the mean level of IL-6 in the supernatant was significantly correlated with the percentage of lymphocytes in bronchoalveolar lavage fluid (p less than 0.05), the level of interleukin-1 released by alveolar macrophages stimulated by P. acnes (p less than 0.05), and the phagocytic index of alveolar macrophages (p less than 0.05). The large amount of IL-6 in the supernatant after stimulation by LPS was measured in patients with sarcoidosis (24.49 +/- 13.36) and in controls (12.4 +/- 8.53), and there was no significant difference between patients with sarcoidosis and controls. Small amounts of IL-6 were detectable in bronchoalveolar fluid from only 2 of 26 patients with sarcoidosis; however, it was detected in none of 15 controls. It is suggested that the enhancement of IL-6 release by alveolar macrophages has a role in the activation of immune effector cells at sites of sarcoidosis.

Adult↗
PubMed1991

8-Methyladenosine-substituted analogues of 2-5A: synthesis and their biological activities.

8-Methyladenosine-substituted analogues of 2-5A, p5'A2'p5'A2'p5'(me8A), p5'A2'p5'(me8A)2'p5'(me8A), p5'(me8A)2'p5'(me8A)2'p5'(me8A), and p5'(me8A) 2'p5'A2'p5'A, were prepared via a modification of a lead ion-catalyzed ligation reaction. These 2-5A monophosphates were converted into the corresponding 5'-triphosphates. Substitution of an 8-methyladenosine residue at the third position (2'-terminus) of the oligonucleotides increased the stability to snake venom phosphodiesterase digestion. Both binding and activation of mouse liver 2-5A dependent ribonuclease (RNase L) by the various 8-methyladenosine-substituted 2-5A analogues were examined. Among the 8-methyladenosine-substituted trimer analogues, the analogues with 8-methyladenosine residing in the 2'-terminal position showed the strongest binding affinity and were several times more effective than 2-5A itself as an inhibitor of translation.

Adenine Nucleotides↗
PubMed1991

Characterization of the carbohydrate chain on the substance P receptor in the rat brain cortex: effect of lectins on [3H]substance P binding.

The characteristics of the carbohydrate chain on the rat cerebral cortical substance P (SP) receptor were studied. We examined the effects of pretreatment with three lectins (concanavalin A, wheat germ agglutinin, lens culinaris agglutinin) on the [3H]SP binding activities. Each lectin can bind to the specific carbohydrate chain. Among these lectins, only concanavalin A inhibited specific [3H]SP binding by reducing the affinity of the binding sites. The inhibitory action of concanavalin A was dose-dependent and diminished by the addition of alpha-methyl-D-mannoside. The present results suggest that the rat cortical SP receptor has either a biantennary complex-type or a high mannose-type of carbohydrate chain, and that the carbohydrate chain is implicated in the SP binding activity of the SP receptor system.

Animals↗