Biomedical subjects

K Sakai

Publications and source records attributed to K Sakai.

At least 883 records · Page 49Linked to original sources

PubMed1991

[Factors related to serum lipid levels in women of middle and old age--a community study].

Serum lipid levels of 168 women ranging in age from 30 to 69 were measured at a mass health screening in an urban community in Saitama prefecture. Degree of obesity, skinfold thickness and blood pressure were measured and the relation between these physical measurements to serum lipid levels was studied. The results are as follows: (1) Mean total cholesterol level, degree of obesity, systolic blood pressure and diastolic blood pressure increased linearly with advancing age. (2) Simple correlation analysis disclosed that the level of total cholesterol was positively correlated to age, degree of obesity, systolic blood pressure and triglyceride level. HDL-cholesterol level showed a significantly negative correlation to degree of obesity, skinfold thickness and triglyceride level. Degree of obesity was positively correlated to skinfold thickness, systolic blood pressure, diastolic blood pressure, total cholesterol and triglyceride level, but was negatively correlated to HDL-cholesterol. Systolic blood pressure had a positive correlation with age, degree of obesity, diastolic blood pressure, total cholesterol and triglyceride level. (3) Principal component analysis, when performed with the variables age, degree of obesity, skinfold thickness, systolic blood pressure, diastolic blood pressure, level of total cholesterol, triglyceride and HDL-cholesterol, showed that subjects could be divided into the group having obesity with low HDL-cholesterol (first principal component), the hypertensive group (second principal component), and the group having hyperlipidemia with advancing age (third principal component). (4) Multiple regression analysis was also carried out, taking HDL-cholesterol level as the dependent variable, and age, degree of obesity, systolic blood pressure, total cholesterol and triglyceride level as independent variables. Degree of obesity and triglyceride level were negatively related to HDL-cholesterol.

Adult↗

PubMed1991

Pulmonary surfactant obtained from starved rats enhances phagocytosis of alveolar macrophages.

Phagocytic activity of alveolar macrophages (AM) was enhanced by pulmonary surfactant obtained from bronchoalveolar lavage fluid of rats starved for 2 days, as compared to fed. The enhanced activity of phagocytosis was dependent on the dose of surfactant. The prepared surfactant showed a different protein to phospholipid ratio of 0.108 in fed and 0.234 in 2 days starved, because of an increased ratio of protein in surfactant from 2 days starved rats. F(ab')2 anti-surfactant protein inhibited the enhanced AM phagocytosis by surfactant. These results suggested that the enhancement of AM phagocytosis in 2 days starved rats was on account of an increase of protein in their surfactant compared to fed.

Animals↗

PubMed1991

Long-term survival and complications after composite graft replacement for ascending aortic aneurysm associated with aortic regurgitation.

The Bentall operation was performed in 44 patients between March 1972 and December 1988. Twenty patients had stigmata of Marfan's syndrome, and 15 had aortic dissection. All showed annuloaortic ectasia. Follow-up ranged from 1 to 16 years (mean, 5.8 years). There were six early deaths (14%) and seven late deaths (16%), with actuarial survival at 10 years of 65 +/- 8%. The late deaths were mostly related to aneurysms occurring in the remainder of the aorta. No patient has undergone reoperation related to the composite graft, but six patients required seven subsequent operations on the remaining aorta. The actuarial probability of freedom from late death and subsequent operation at 8 years was 64 +/- 9% for the operative survivors, but it was 44 +/- 17% for the patients with aortic dissection and 37 +/- 19% for those with Marfan's syndrome. Postoperative angiography performed 3-168 months (mean, 42 months) postoperatively in 23 nonselective patients demonstrated recurrent true aneurysms at both or one of the coronary ostia (seven), persistent dissection distal to the distal aortic anastomosis (five), pseudoaneurysm at the left coronary ostium (one), pseudoaneurysm due to a small leak at the proximal aortic anastomosis (one), and partial dehiscence of the distal aortic suture line (one). Composite graft replacement carries a potential risk of various late complications. Our data support the concept that earlier detection and aggressive treatment of the late complications occurring in the remainder of the diseased aorta is necessary to improve long-term survival after the Bentall operation.

Actuarial Analysis↗

PubMed1991

[A study of the adhesive resins used in adhesion bridges].

UNLABELLED: We suspected that the composition of stiffened adhesive resins may cause adhesion bridges to drop out. In this study, by using a scanning type electron microscope, we observed the breaking sides of the adhesive resin after the tension test. We also examined the surfaces of the resin that we cut and ground after it had hardened, and the surfaces of the adhesion bridges that dropped out. RESULTS: 1) RESULTS of the tension test. No significant differences between the adhesive resins were observed. We noticed no significant differences between the metal surface treatment methods. 2) Observations of the breaking side after the tension test. When we examined Panavia EX, we observed flaking of the metallic side and the tooth enamel. We noticed that the surface was smooth regardless of the method of preprocessing the metal. But the surface of the adhesive resin was bumpy, and we found bubbles of different sizes on the resin surfaces. When we examined Super-Bond C&B, we observed flaking of the metallic side and the tooth enamel, and the surfaces were smooth regardless of the method of preprocessing the metal. Unlike Panavia EX, however, we found various hollows, big and small, like the bubbles on the smooth surfaces of Super-Bond C&B. 3) Observations of the abrasive surface of stiffened adhesive resins. With an ambient temperature of 15 and 28 degrees, we found many minute hollows like bubbles on the abrasive surfaces of Panavia EX and Super-Bond C&B. 4) Observations of the surface of the bonding materials of the adhesion bridges which dropped out. We found bumpy surfaces on the adhesive resin which remained on the metallic side of the adhesion bridges, whichever position the adhesion bridges dropped out of.

Boron Compounds↗

PubMed1991

[Electrocardiographic findings and their relationship to blood pressure, obesity and serum lipids in the middle and old aged at a localized community].

Electrocardiographic findings and their relationship to blood pressure, degree of obesity, skinfold thickness, total cholesterol and triglyceride level were studied using health examination results. The subjects were 855 residents ranging in age from 40 to 79 from a localized community in Saitama prefecture who participated in a health examination. For electrocardiographic findings, left ventricural hypertrophy (LVH) and ST, T changes were adopted as predictive parameters which were closely related to incidence of coronary heart disease. The results are summarized as follow: 1) Results of the electrocardiograms showed high frequencies of LVH and ST, T changes. Frequency of both LVH and ST, T changes increased linearly with advancing age. Frequency of LVH was significantly higher in men than women. Frequency of ST, T changes was higher in women than men. 2) As to predictive parameters of coronary heart disease, frequency of LVH was positively associated with systolic blood pressure, but was negatively associated with skinfold thickness. In females, frequency of LVH was negatively related to obesity, and frequency of ST, T changes was significantly related to systolic blood pressure and obesity. While frequency of ST, T changes was associated with increase in total cholesterol level, it was not significant. However ST, T changes were shown to be significantly related to triglyceride level.

Adult↗

PubMed1991

A five-year appraisal and hemodynamic evaluation of the Björk-Shiley Monostrut valve.

Two hundred forty-four Björk-Shiley Monostrut valves were implanted in 225 consecutive patients from October 1983 to December 1988. Aortic valve replacement was performed in 90 patients, mitral valve replacement in 118, and double valve replacement in 16 patients. One patient had tricuspid valve replacement. There were 100 female patients and 125 male patients with a mean age of 54 years (range 2 to 71 years). Present data were completely available for all patients. The cumulative follow-up was 541 patient-years with a mean of 2 years, 5 months. The closing date for follow-up was July 1989, and the closing interval was 2 months. The early mortality rate was 3.1%, and the late mortality rate, 3.1%. The 5-year survival rate was 88% +/- 2.0%: 87% +/- 3.0% for aortic valve replacement, 91% +/- 3.3% for mitral valve replacement, and 75% +/- 9.6% for double valve replacement. The actuarial rates of freedom from thromboembolism at 5 years were 93% +/- 3.2% for aortic, 96% +/- 1.4% for mitral, and 94% +/- 6.1% for double valve replacement. There were no instances of structural valve deterioration. Actuarial rate of freedom from valve-related morbidity and mortality was 86% +/- 2.0% at 5 years: 86% +/- 9.5% for aortic, 87% +/- 3.3% for mitral, and 75% +/- 7.3% for double valve replacement. Effective valve areas (average) of 12 mitral and 12 aortic valve prostheses were calculated at rest and during bicycle exercise: 2.4 cm2 at rest and 2.8 cm2 during exercise in 27 mm aortic valves, 2.4 cm2 at rest and 3.0 cm2 during exercise in 25 mm aortic valves, 2.0 cm2 at rest and 2.4 cm2 during exercise in 27 mm mitral valves, and 2.6 cm2 at rest and 2.5 cm2 during exercise in 29 mm mitral valve. On the basis of our follow-up period of 5 years, we have judged the Björk-Shiley Monostrut valve reliable, with a low incidence of valve-related morbidity and with acceptably satisfactory hemodynamic characteristics at rest and during exercise.

Adolescent↗

PubMed1991

[Intercostal nerve cross-anastomosis and DREZ-tomy in a patient with brachial plexus avulsion].

An 18-year-old male with a right brachial plexus injury caused by a motorcycle accident was admitted on October 13, 1988. A detailed examination revealed that the brachial plexus was totally injured. The axon reflex test suggested that the lesion sites were postganglionic in the C5 and C6 nerves, and preganglionic in the C7, C8 and Th1. On December 14, 1988, intercostal nerve cross-anastomosis was performed in the hope that a lost motor function of the right upper extremity could be restored as a first step. An electromyogram 6 months after this anastomotic operation demonstrated synkinesis between the biceps brachialis and the intercostal muscles during deep inspiration. Fifteen months after this operation, active voluntary muscle discharges which were higher than before in amplitude, were provoked. The right elbow flexion was gradually restored independently of respiration. On the other hand, intractable pain with a persistent severe tingling sensation appeared approximately one week after the injury on the lesioned upper extremity. The pain rapidly increased in severity. The DREZ-tomy from C5 to Th1 was performed on March 7, 1989. This has brought complete relief of the intractable pain. A brief discussion was given concerning some aspects of the brachial plexus avulsion and DREZ-tomy.

Adolescent↗

PubMed1991

Staging and follow-up of primary gastric lymphoma by endoscopic ultrasonography.

The usefulness of endoscopic ultrasonography (EUS) was assessed for diagnosing the depth of invasion in the gastric wall, the infiltration to the adjacent organs, and detecting regional lymph node involvement in primary gastric lymphoma. EUS was performed in 11 patients with primary gastric lymphoma who subsequently underwent gastrectomy with lymph node dissection, as well as chemotherapy in some cases. EUS findings showed a good correlation with the histopathology of the resected specimens. An accurate diagnosis of the depth of invasion into the gastric wall was made in 10 of 11 patients using the same T grade of the 1987 TNM system for gastric carcinoma. EUS also clearly visualized the reduction of depth of tumor invasion in two patients who underwent chemotherapy. Perigastric lymph node involvement could be detected accurately in nine of 11 patients. In conclusion, EUS is an excellent and sensitive diagnostic modality for the preoperative staging and follow-up of primary gastric lymphoma.

Aged↗

PubMed1991

[A close relationship between the renal potassium regulation and the maximum binding of ouabain to erythrocytes].

Maximum binding of ouabain to erythrocytes (Bmax), serum K, urinary aldosterone excretion (U-Aldo) and fractional excretion of filtered K (FEK) were examined in 69 healthy children aged 12 to 15 years to assess the relationship between the sodium pump receptor in erythrocytes and the renal handling of potassium (K). Bmax showed a significant negative correlation with FEK. Subsequently, FEK showed a negative correlation with serum K which was within normal range in every child, and a positive correlation with U-Aldo. However, Bmax showed no correlation with serum K or U-Aldo. These findings suggest that aldosterone may influence Bmax via the changes in FEK and serum K within physiological ranges. In other words, there can exist a close relation between Bmax and the renin-angiotensin-aldosterone system through K metabolism.

Adolescent↗

PubMed1991

Morphological heterogeneity among fractionated alveolar macrophages in their release of lysosomal enzymes.

When coupled with separation of alveolar macrophages (AM) into four different density fractions (I, II, III and IV) by discontinuous Percoll gradient centrifugation, ultrastructural heterogeneity was evident in secreting process of lysosomal enzymes. Lower dense AM (I and II) released high levels of acid phosphatase and cathepsin B, whereas higher dense ones (III and IV) did not. Ultrastructurally, there were multiple ruffling and active extension of long cytoplasmic processes from one pole or around the cell surface of AM obtained from the higher density fractions. In contrast, AM from lower dense fractions had much less cytoplasmic processes and contained more cytoplasmic vacuoles showing positive reactions of acid phosphatase. These cells featured more frequently round or ovoid knobs with acid phosphatase activity along and from the tips of the cytoplasmic processes, suggestive of exocytosis. It was suggested that these ultrastructural changes linked to the maturation process and release of lysosomal enzymes from differentiated AM.

Acid Phosphatase↗

PubMed1990

Nuclei of origin of monoaminergic, peptidergic, and cholinergic afferents to the cat trigeminal motor nucleus: a double-labeling study with cholera-toxin as a retrograde tracer.

The aim of the present study was to determine the brainstem afferents and the location of neurons giving rise to monoaminergic, cholinergic, and peptidergic inputs to the cat trigeminal motor nucleus (TMN). This was done in colchicine treated animals by using a very sensitive double immunostaining technique with unconjugated cholera-toxin B subunit (CT) as a retrograde tracer. After CT injections in the TMN, retrogradely labeled neurons were most frequently seen bilaterally in the nuclei reticularis parvicellularis and dorsalis of the medulla oblongata, the alaminar spinal trigeminal nucleus (magnocellular division), and the adjacent pontine juxtatrigeminal region and in the ipsilateral mesencephalic trigeminal nucleus. We further observed that inputs to the TMN arise from the medial medullary reticular formation (the nuclei retricularis magnocellularis and gigantocellularis), the principal bilateral sensory trigeminal nucleus, and the dorsolateral pontine tegmentum. In addition, the present study demonstrated that the TMN received 1) serotonergic afferents, mainly from the nuclei raphe obscurus, pallidus, and dorsalis; 2) catecholaminergic afferent projections originating exclusively in the dorsolateral pontine tegmentum, including the Kölliker-Fuse, parabrachialis lateralis, and locus subcoeruleus nuclei; further, that 3) methionin-enkephalin-like inputs were located principally in the medial medullary reticular formation (nuclei reticularis magnocellularis and gigantocellularis and nucleus paragigantocellularis lateralis), in the caudal raphe nuclei (Rpa and Rob) and the dorsolateral pontine tegmentum; 4) substance P-like immunoreactive neurons projecting to the TMN were present in the caudal raphe and Edinger-Westphal nuclei; and 5) cholinergic afferents originated in the whole extent of the nuclei reticularis parvicellularis and dorsalis including an area located ventral to the nucleus of the solitary tract at the level of the obex. In the light of these anatomical data, the present report discusses the possible physiological involvement of TMN inputs in the generation of the trigeminal jaw-closer muscular atonia occurring during the periods of paradoxical sleep in the cat.

Afferent Pathways↗

PubMed1990

Two glyceraldehyde-3-phosphate dehydrogenase isozymes from the koningic acid (heptelidic acid) producer Trichoderma koningii.

The sesquiterpene lactone koningic acid (heptelidic acid) irreversibly inactivated glyceraldehyde-3-phosphate dehydrogenase [D-glyceraldehyde 3-phosphate: NAD+ oxidoreductase (phosphorylating)] (EC 1.2.1.12) (GAPDH) and thus inhibits glycolysis. The koningic-acid-producing strain of Trichoderma koningii M3947 was shown to contain the koningic-acid-resistant GAPDH isozyme (GAPDH I) under conditions of koningic acid production. In peptone-rich medium, however, no koningic acid production was observed, and the koningic-acid-sensitive GAPDH isozyme (GAPDH II), in addition to the resistant enzyme, was produced. Both enzymes were tetramer with a molecular mass of 152 kDa (4 x 38 kDa) and lost enzyme activity when two of the four cysteine residues reacted with koningic acid. The apparent Km values of GAPDH I and II for glyceraldehyde 3-phosphate were 0.54 mM and 0.33 mM, respectively. The former isozyme was inhibited 50% by 1 mM koningic acid but not affected at 0.1 mM, while the latter isozyme was inhibited 50% at 0.01 mM. The immunochemical properties and partial amino acid sequences suggested that the two isozymes have different molecular structures. These results suggest that GAPDH I is responsible for the glycolysis in T. koningii when koningic acid is produced.

Amino Acid Sequence↗

PubMed1990

Inhibition by carbachol microinjections of presumptive cholinergic PGO-on neurons in freely moving cats.

The effects of microinjections of a cholinergic agonist, carbachol (0.2 micrograms/0.2 microliters), were examined on a population of presumptive cholinergic mesopontine PGO-on neurons that presents a tonic pattern of discharge during waking and exhibits short spike bursts preceding the onset of dorsal lateral geniculate PGO waves during paradoxical sleep and slow wave sleep just prior to it. PGO-on neurons were activated antidromically by the stimulation of the dorsal lateral geniculate, pulvinar and/or medial and intralaminar thalamic nuclei. They were all characterized by a long spike duration and a slow conduction velocity. Microinjections of carbachol near unit recording sites in freely moving cats induced a complete suppression of the spontaneous tonic activity during waking, but did not suppress the spontaneous phasic burst activity during sleep. Carbachol microinjections also resulted in a marked reduction in responsiveness of PGO-on neurons to orthodromic stimulation. These spike depressant effects lasted for approximately 90-120 min and were reversed completely by a local or systemic administration of atropine sulfate. These findings point to a direct inhibition of central cholinergic PGO-on neurons via a muscarinic autoreceptor and a difference in the mechanisms underlying the generation of tonic and phasic burst activity of PGO-on neurons occurring during waking and sleep.

Animals↗

PubMed1990

Involvement of histaminergic neurons in arousal mechanisms demonstrated with H3-receptor ligands in the cat.

The effects of histamine H3-receptor ligands on sleep-waking parameters were studied in freely moving cats. Oral administration of (R)alpha-methylhistamine (alpha MHA), a H3-agonist, caused a significant increase in deep slow wave sleep while that of thioperamide, a H3-antagonist, enhanced wakefulness in a marked and dose-dependent manner. The arousal effects of thioperamide were prevented by pretreatment with alpha MHA or mepyramine, a H1-receptor antagonist. The findings support the hypothesis that the histaminergic neurons are critically involved in arousal mechanisms and suggest that H3-receptors play an active part in these mechanisms by regulating histamine transmission.

Animals↗

PubMed1990

Phenotype analyses and cellular mechanisms of the pre-effector T-lymphocyte response to a progressive syngeneic murine sarcoma.

Lymph nodes draining the progressively growing, weakly immunogenic, MCA 105 sarcoma contained tumor-sensitized but not fully functional pre-effector T-cells. These cells could further differentiate to acquire full antitumor effector function for adoptive therapy in an established in vitro sensitization (IVS) procedure. In this study, we utilized selective depletion with antibodies of lymphocyte subsets bearing the L3T4 (CD4) or Lyt-2 (CD8) antigen and of cells bearing the asialo-GM1 (ASGM-1) glycosphingolipid to identify the phenotype of pre-effector cells elicited during progressive tumor growth. Cells from lymph nodes draining a progressive MCA 105 tumor in the footpad were treated with antibodies plus complement prior to IVS. The antitumor efficacy of resulting IVS cells was assessed in adoptive therapy of 3-day established pulmonary MCA 105 metastases. Depletion of Lyt-2+ cells eliminated in vivo antitumor reactivity with concurrent elimination of in vitro cytotoxic activity against the MCA 105 tumor, whereas depletion of L3T4+ cells did not have an impact on either in vivo or in vitro antitumor reactivities. Treatment with ASGM-1 antiserum plus complement was also found to abrogate therapeutic efficacy. However, the in vitro cytotoxic activity was not affected. These results indicate that the pre-effector cells were Lyt-2+, L3T4-, and ASGM-1+. We next examined whether the sensitization of pre-effector cells in vivo required the participation of L3T4+ helper cells. To approach this, mice were depleted of L3T4+, Lyt-2+, or ASGM-1+ cells by antibody injections before tumor inoculation. Treatment with Lyt-2 monoclonal antibody abrogated the pre-effector cell response in the draining lymph nodes, as evidenced by failure to generate therapeutically effective cells following IVS. On the other hand, neither L3T4 nor ASGM-1 antibody treatment affected the generation of pre-effector cells. Thus, sensitization of Lyt-2+ pre-effector cells in response to progressive tumor occurred in the absence of L3T4+ helper cells.

Animals↗

PubMed1990

Mechanisms of anti-CD4-mediated depletion and immunotherapy. A study using a set of chimeric anti-CD4 antibodies.

A family of rat-mouse chimeric anti-murine CD4 antibodies was used to study the mechanisms of anti-CD4-mediated depletion and immunotherapy. The chimeric antibodies retain identical affinity and specificity as the therapeutically effective prototype antibody, rat GK1.5, but are of different mouse isotypes. GK1.5 gamma 1, GK1.5 gamma 2a, and GK1.5 gamma 2b are significantly more effective at CD4+ cell depletion than rat GK1.5 when low doses of antibody are administered. In contrast, no depletion is seen with GK1.5 gamma 3 at any dose. Depletion of CD4+ cells in vivo is not correlated with either the ability of the antibody to mediate C-dependent cytotoxicity or antibody-dependent cell-mediated cytotoxicity in vitro, implying that additional antibody-mediated cytotoxic mechanisms occur in vivo. The chimeric antibodies were used to investigate the mechanism of GK1.5-mediated immunotherapy in a prototypic model of T cell-mediated autoimmunity, experimental allergic encephalomyelitis. Mice treated with a single dose of 100 micrograms of either GK1.5, GK1.5 gamma 1, or GK1.5 gamma 2a showed significant recovery within 72 h. In contrast, mice treated with 100 micrograms of GK1.5 gamma 3 showed only marginal improvement within the first 72 h and regressed within 5 days of treatment initiation. These data suggest that anti-CD4-mediated immunotherapy of murine experimental allergic encephalomyelitis is correlated with depletion of CD4+ cells.

Animals↗

PubMed1990

Purification and characterization of an exo-beta-D-glucosaminidase, a novel type of enzyme, from Nocardia orientalis.

A new enzyme capable of hydrolyzing chitobiose, which is an induced enzyme, was purified to apparent homogeneity from the culture filtrate of Nocardia orientalis IFO 12806. Biospecific affinity chromatography on chitotriitol-Sepharose CL-4B was effective for purification of this enzyme. It is clearly demonstrated that the enzyme is an exo-hydrolase, removing single glucosamine residues from the nonreducing terminal of a sequence of beta-(1----4)-linked glucosamine chain, such as chitosan and chitooligosaccharides, and therefore characterized as an exo-beta-D-glucosaminidase. The enzyme was found to show maximum activity on chitotetraose, chitopentaose, and their corresponding alcohols and a slight decrease in rate on longer chain lengths of substrates. A significant decrease in rate was observed using p-nitrophenyl beta-D-glucosaminide and chitobiitol as substrates. In the hydrolysis of partially acetylated chitosans, the enzyme appeared to be effective in cleaving glucosamine from the GlcN beta 1----4GlcNAc beta 1----sequence as well as the GlcN beta 1----4GlcN beta 1----sequence. These observations suggest that the second residue from the terminal plays an important role in enzyme activity, but the enzyme permits the replacement of glucosamine at the second residue by N-acetylglucosamine.

Chitin↗

PubMed1990

HTLV-I sequences are not detected in peripheral blood genomic DNA or in brain cDNA of multiple sclerosis patients.

Human T-cell lymphotropic virus (HTLV-I) was recently reported to be etiologically associated with multiple sclerosis (MS). Genomic DNA from peripheral blood lymphocytes and brain plaques of patients with MS was analyzed for the presence of sequences homologous to the HTLV-I pol gene using the polymerase chain reaction and dot blot techniques. Comparison of DNA amplification patterns between patients with MS, and with control subjects who have other autoimmune conditions, with those in healthy control subjects and with an HTLV-I-infected cell line indicates that HTLV-I pol sequence is not present in the peripheral blood of patients with MS, and that the virus is not active in MS brain plaques.

Autoimmune Diseases↗