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Biomedical subjects

Y Masaki

Publications and source records attributed to Y Masaki.

At least 91 records · Page 5Linked to original sources
PubMed1994

Experimental laser anastomosis of the colon. Long-term results and histologic findings after laser closure of colotomies.

PURPOSE: Our previous experimental work showed the feasibility of colon anastomosis using laser; however, it also revealed a narrowing tendency after laser anastomosis. Long-term observation of the postoperative course of laser anastomosis was planned to assess this point. METHODS: Clinical observation and histologic examination of transverse colotomies (average, 21.2 mm) in New Zealand white rabbits (n = 12) closed with a 1,064-nm neodymiumyttrium aluminum garnet (Nd:YAG) laser were carried out up to the third postoperative month, compared with closure of colotomies using a single layer of interrupted sutures of 5-0 Maxon (Davis & Geck, Pearl River, NY) in a control group (n = 12). RESULTS: Whereas the narrowing tendency was observed up to one month after the operation in the laser group (P < 0.05), it disappeared at three months following the operation without causing abnormal weight loss during the experiment. Simultaneously, there was again a marked decrease in adhesion formation following laser anastomosis (P < 0.01). Collagen fibers were observed earlier in the laser group. CONCLUSIONS: An earlier commencement of collagen synthesis after laser anastomosis was proved. A narrowing tendency, which was observed from seven days to one month postoperatively, disappeared at three months after laser anastomosis without exerting any effect on growth.

Anastomosis, Surgical↗
PubMed1994

Effect of altering cerebrospinal fluid pressure on spinal cord blood flow.

Removal of cerebrospinal fluid (CSF) has been proposed as a means of protecting the spinal cord against ischemic injury during thoracoabdominal aneurysm operations. We investigated the effect of altering CSF pressure (CSFP) on lumbar spinal cord blood flow (SCBF) in an experiment using dogs. The SCBF was measured before and after withdrawal of CSF in settings with and without thoracic aortic clamping. Furthermore, SCBF was measured at the basal state and after elevation of CSFP to 20 mm Hg and to 40 mm Hg. The SCBF did not change significantly before and after removal of CSF in settings both with and without thoracic aortic clamping. Elevation of CSFP significantly reduced SCBF. Elevation of CSFP reduces SCBF, but lowering CSFP per se does not increase SCBF whether the thoracic aorta is occluded or not. This supports the notion that removal of CSF offers spinal cord protection only when CSFP is abnormally elevated.

Animals↗
PubMed1994

Sweet's syndrome during therapy with granulocyte colony-stimulating factor in a patient with aplastic anaemia.

A patient with aplastic anaemia developed Sweet's syndrome (a febrile neutrophilic dermatosis) during granulocyte colony-stimulating factor (G-CSF) therapy. Three repeated episodes of appearance and disappearance of erythematous nodules after administration and withdrawal of G-CSF confirmed that G-CSF induced Sweet's syndrome in the patient. Sweet's syndrome has been reported in patients with myelodysplastic syndrome and acute leukemia, but not in patients with aplastic anaemia. This is the first report of a patient with aplastic anaemia who developed G-CSF-induced Sweet's syndrome.

Adult↗
PubMed1994

In vivo, in vitro correlation of acetylcholine airway responsiveness in sensitized guinea pigs. The role of modified epithelial functions.

Many attempts have failed to correlate in vivo airway responsiveness with in vitro airway smooth muscle functions. We have reexamined this relation by taking account of airway epithelial functions in guinea pigs sensitized with inhaled ovalbumin (OA). In vivo responses were assessed by the provocative concentration of acetylcholine (ACh) required to double the airway opening pressure (PC200) under mechanical ventilation. In vitro responses were measured in a perfused whole-tracheal preparation. The negative logarithm of the molar concentration of ACh required to produce a 10% reduction in diameter was calculated both for epithelial-side stimulation (PC10(in)) and for serosal-side stimulation (PC10(out)). OA-sensitized guinea pigs showed significantly smaller log PC200 than control animals (0.51 +/- 0.07 and 0.81 +/- 0.10, respectively, p < 0.01). In in vitro study, there were variable differences in PC10(in) and PC10(out) in each animal. The difference in sensitivity between epithelial- and serosal-side stimulation (PC10(in-out)) showed a significant correlation in PC10(in) (r = 0.82, n = 9, p < 0.01) but not to PC10(out) (r = 0.39, p > 0.1), indicating that the variation in PC10(in-out) resulted from the changes in PC10(in). For in vivo-in vitro correlation, log PC200 correlated significantly with PC10(in) (r = 0.68, n = 9, p < 0.05) but not with PC10(out) (r = 0.18, p > 0.1). These results indicate that the sensitization by inhalation of OA produces increased airway responsiveness to ACh in vivo and that this airway responsiveness may be related, at least in part, to the altered airway epithelial functions.

Acetylcholine↗
PubMed1994

Gamma-interferon modifies guinea pig airway functions in vitro.

Cytokines produced by T-lymphocytes may have significant roles in the airway inflammation seen in bronchial asthma. Gamma interferon (IFN-gamma), a T-cell derived cytokine, is known to modify functions of both immune and non-immune cells. In this study, we investigated whether IFN-gamma can modify guinea pig airway functions in vitro. The isometric tension of guinea pig airway strips was measured in a tissue bath filled with Krebs-Henseleit solution. Contracting responses to carbachol and KCl, and the relaxing response to isoproterenol (ISO) were examined. Effects of IFN-gamma were examined by comparing responses of the strips incubated with or without IFN-gamma (1000 U.ml-1; 25,000 U.ml-1). Contracting responses to carbachol and KCl were not affected by the incubation with IFN-gamma other than slight increased in maximum contraction by carbachol after 5 hours incubation with 25,000 U.ml-1 of IFN-gamma. Both 1 and 5 h incubation of strips with 25,000 U.ml-1 IFN-gamma significantly increased the sensitivity to ISO (p < 0.01 and p < 0.05, respectively) without affecting maximum relaxation. The effect of IFN-gamma on ISO relaxation was abolished by the denudation of airway epithelium from strips, indomethacin (2 microM), and cycloheximide (70 microM) but not by N omega-nitro-L-arginine methyl ester (30 microM). In addition, heat-inactivated IFN-gamma and bacterial endotoxin (LPS, 0.625 pg.ml-1) had no effect on ISO relaxation. These results suggest that IFN-gamma is able to modify airway smooth muscle response to beta-adrenergic agonist by inducing release of prostanoids from airway epithelium.

Animals↗
PubMed1994

Induction of ovulation by endothelin-3 in rats.

Endothelins vary in their biological activity. We therefore examined the effects of endothelin-3 (ET-3) on ovulation and secretion of LH, FSH and prolactin in rats in which naturally occurring ovulation was blocked by the administration of sodium pentobarbital (40 mg/kg, i.p.) prior to the critical period (1330 h) on the day of pro-oestrus. ET-3 (10 nmol/kg) was given via the jugular vein under pentobarbital anaesthesia from 1600 to 1800 h on the day of pro-oestrous and induced ovulation in all rats whether given by venous injection or by infusion but the number of ova in rats injected with ET-3 was less than that in normally cycling control rats. Infusion of ET-3 stimulated the secretion of LH but caused a lower than expected rate of secretion of FSH. It would therefore appear that ET-3 causes release of the total amount of LH that is required for induction of ovulation. Our findings strongly suggest that ET-3 has a physiologically significant role in the regulation of anterior pituitary hormone secretion.

Animals↗
PubMed1994

Effect of daily subcutaneous administration of recombinant erythropoietin on chronic anemia in rheumatoid arthritis.

Mean (+/- SD) serum erythropoietin (EPO) levels were 18.6 +/- 5.6 mU/ml in 180 normal Japanese subjects. Serum EPO levels were elevated with a negative correlation on a log scale (r = -0.864, P < 0.005) to hematocrit (Ht) values in anemic patients not associated with rheumatoid arthritis (RA) or chronic renal failure (CRF). Serum EPO levels in patients with RA (31.6 +/- 16.4 mU/ml) were relatively lower than those in normal subjects and anemic patients without RA or CRF when matched for comparative Ht values. Seven anemic patients with RA were treated by daily subcutaneous (sc) injection of recombinant EPO (rEPO, 500-1,000 U/day) for 4 weeks. The patients had initial Ht values of 25.1% or less and maintained stable clinical status. The treatment with rEPO raised serum EPO levels (53.8 +/- 15.2 mU/ml, P < 0.05), which resulted in an increase in Ht values (more than 3%) in 6 out of 7 patients with RA. The mean (+/- SD) Ht values at the end of the treatment with rEPO (500-1,000 U/day) were greater than those before the treatment in the 7 patients with RA (28.5 +/- 4.6 vs. 22.7 +/- 2.5%, P < 0.05). These findings suggest that chronic anemia associated with RA may be corrected by daily sc injection of a small dose of rEPO.

Adult↗
PubMed1994

Clinical characteristics of idiopathic interstitial pneumonia (IIP) with bullae.

Multiple bullae have often been observed in the lungs of patients with idiopathic interstitial pneumonia (IIP). The etiology of bullae has been considered to be distinct from that of interstitial pneumonia and honeycomb lesions seen in IIP. The incidence of bullae was evaluated in 27 IIP patients (male; 23 cases, female; 4 cases) and clinical factors which are related to the development of bulla were analyzed. Of the 27 patients, 16 (59%) had bullae. All 16 were male smokers, and had higher smoking indices (p < 0.01) than patients without bullae. Eleven of the 16 IIP patients with bullae had clubbed fingers (69%, p < 0.05). Roentgenologically, cysts (75%, p < 0.05), low attenuation area (56%, p = 0.06), and honeycomb appearance (94%, p = 0.07) were observed more often in IIP patients with bullae. These results suggest that smoking habits may have a close relationship to the development of bullae seen in patients with IIP.

Aged↗
PubMed1994

[Changes of respiratory function after lung resection--taking notice of changes during exercise test and anaerobic metabolism].

Changes in the following respiratory functions during exercise test were examined before and after surgery in 31 patients undergoing pulmonary resection: VE, VCO2, and VT at a constant VO2 during exercise; and VO2, VCO2, VE and VT at constant loading (watt). At the level of 300 and 500 ml/min of VO2, VCO2 showed no significant difference before and after the operation but when VO2 reached 700 ml/min. VCO2 showed a significant increase from 542.0 +/- 78.3 ml/min to 595.5 +/- 85.2 ml/min postoperatively (p < 0.05). When exercise load was 45 watt, VE showed no significant difference before and after the operation, but when exercise load was 60 watt, VE showed a significant increase from 30.16 +/- 5.38 L/min to 33.89 +/- 4.69 L/min postoperatively (p < 0.005). These results indicated an early acceleration of ventilation in low load postoperatively. With respect to anaerobic metabolism, AT, oxygen uptake to work rate (delta VO2/delta WR), and our proposed index calculated as an area using the cumulative oxygen uptake were compared pre- and postoperatively. The results indicated that AT decreased significantly from 716.0 +/- 190.8 ml/min to 528.4 +/- 150.7 ml/min (p < 0.001), and delta VO2/delta WR also decreased significantly from 13.5 +/- 4.0 ml/min/W to 11.3 +/- 4.2 ml/min/W (p < 0.05). The index calculated as area showed a significant increase from 4070.2 +/- 3468.8 to 5095.3 +/- 3854.5 (p < 0.05). All these findings indicated that anaerobic metabolism increases postoperatively. Accordingly we conclude that postoperative increase of anaerobic metabolism causes postoperative acceleration of ventilation in low load.

Adult↗
PubMed1994

[Antigen-induced pulmonary arterial responses in the isolated perfused lung of sensitized rabbits].

To investigate whether blood components, such as complements, antibody, platelets and leukocytes, can play important roles in increasing pulmonary arterial and airway pressures after antigen challenge in sensitized rabbits, we measured the time course of pulmonary arterial pressure, airway pressure and lung weight gain after antigen challenge in isolated perfused rabbit lungs. Nineteen rabbits were divided into 3 groups; S group (n = 9), which was sensitized rabbit lung with antigen added into perfusate; NS group (n = 5), which was nonsensitized rabbit lung with antigen added into perfusate; S+R group (n = 5), which was sensitized rabbit lung with autologous erythrocytes added into perfusate. Although agglutinin titer in sensitized rabbits was more than 1: 10,000, that in the perfusate was less than 1:16. Pulmonary arterial and airway pressures significantly increased after antigen challenge in S group, while those in NS and S+R groups did not show any change. Also there were no significant changes in pulmonary arterial and airway pressures and lung weight gain in nonsensitized rabbit lungs of the same agglutinin titer as S group. Lung weight gain in S group was 2-4 times higher than that in S+R group after antigen challenge. We conclude that blood components, such as complements, antibody, platelets and leukocytes, do not play important roles on antigen induced pulmonary responses in sensitized rabbit lungs.

Airway Resistance↗
PubMed1994

[Successful VEP-IFN-alpha therapy in a case of non-secretory plasma cell leukemia (BJ-kappa type)].

Plasma cell leukemia is a rare disorder with poor prognosis. We present a case of non-secretory primary plasma cell leukemia (Bence-Jones kappa type), which was treated successfully by VEP-IFN-alpha therapy. A 82-year old man was admitted to Kanazawa Medical University in May 1991, because of emaciation and dehydration. Clinical findings showed decreased level of gamma-globulin (IgG, IgA and IgM were all decreased markedly), hypercalcemia, renal dysfunction and increased serum beta-2 microglobulin. The peripheral blood leukocyte count was 30,100/microliters with 64% plasma cells, and 80.4% plasma cells were also observed in the bone marrow. Only light chain-kappa was detected in plasma cells by an immunohistochemical staining method, but immunoelectrophoresis showed no M-bow either in serum or urine. Electron microscopy revealed typical plasma cells with prominently developed rough endoplasmic reticulum. From these results, the diagnosis of non-secretory primary plasma cell leukemia was established. He was treated with VEP-IFN-alpha regimen, and plasma cells decreased markedly in both peripheral blood and bone marrow. Serum immunoglobulin recovered to within the normal range. After 6 courses of VEP-IFN-alpha, complete remission was achieved and the remission was maintained until he died of an unrelated event, bronchial obstruction due to misswallowing, in April 1992.

Aged↗
PubMed1994

[Prostaglandin E1 does not inhibit production of TNF and IL-1 by mononuclear cells after head-neck surgery].

We studied whether human blood mononuclear cells could produce tumor necrosis factor (TNF) and interleukin 1 (IL-1) by surgical stimuli, and if so, prostaglandin E1 (PGE1) could inhibit their increases before and following operation in patients undergoing head-neck surgery. The patients were randomly allocated into 2 groups; no PGE1 infusion group (control group, n = 6) and PGE1 infusion group (PGE1 group, n = 6). PGE1 group was infused intravenously with PGE1 at a rate of 30 ng.kg-1 x min-1 during surgery and at a rate of 10-30 ng.kg-1 x min-1 after surgery. Peripheral blood was withdrawn into heparinized syringes from these patients immediately before surgery and on the 1st postoperative day. Production of TNF on the 1st postoperative day increased 1.5 fold in control group and 1.4 fold in PGE1 group compared with those before surgery. Production of IL-1 on the 1st postoperative day increased 1.7 fold in control group and 1.1 fold in PGE1 group compared with those before surgery. Also, there were no significant differences between 2 groups in both productions of TNF and IL-1. These data indicate that human blood mononuclear cells would produce TNF and IL-1 by surgical stimuli and PGE1 could inhibit their production by surgical stimuli. It also provides evidence that PGE1 does not inhibit the body's defense response to surgical stimuli.

Aged↗
PubMed1993

High-dose 15-deoxyspergualin monotherapy surpasses methylprednisolone in its therapeutic effect on advanced lupus nephritis in New Zealand black/white F1 hybrid mice, and low-dose combination may be synergistic.

To compare the therapeutic effect of 15-deoxyspergualin with that of methylprednisolone on advanced lupus nephropathy of New Zealand black/white F1 hybrid (B/W) mice, and also to study the possible synergistic effect of both drugs, B/W mice were heminephrectomized at 32 weeks of age, and were divided into six groups. Each group of mice was treated with 50 microliters phosphate-buffered saline (PBS), 3 mg/kg methylprednisolone, 20 mg methylprednisolone, 0.6 mg DSP, 6 mg DSP, or with 3 mg methylprednisolone plus 0.6 mg DSP, s.c., four times per week for 8 weeks. Urine and blood samples (by tail vein venipuncture), as well as renal tissue specimens, were taken at 32 and 40 weeks of age. The degree of proteinuria, and serum anti-DNA activity (by ELISA) were determined. Renal specimens were evaluated with light- and immunofluorescence (C3)-microscopy, the degree of pathological changes being semi-quantitated and expressed as total light-microscopy (LM) and immunofluorescence (IF) scores. The survival rate at 40 weeks of age was significantly elevated in 0.6 mg DSP, 6 mg DSP, and methylprednisolone + DSP groups of mice compared with the control group. The appearance rate of significant post-treatment proteinuria was comparable among all groups. The difference (post-treatment titre--pretreatment titre) of serum anti-DNA activity in the 6 mg DSP and methylprednisolone + DSP groups were significantly less, while that of the 3 mg methylprednisolone group was greater compared with the control level. As for the total LM score, the levels significantly decreased in the 6 mg DSP, methylprednisolone + DSP and 3 mg methylprednisolone groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Flavin-photosensitized monomerization of dimethylthymine cyclobutane dimer in the presence of magnesium perchlorate.

We have investigated the photosensitized monomerization of the cis,syn-cyclobutane dimer of 1,3-dimethylthymine using riboflavin tetraacetate and a 5-deazaflavin derivative as photosensitizer. Although little monomerization of the dimer is induced by photoexcitation of the flavins in the absence of any additives, the flavins can function as an efficient photosensitizer in the presence of magnesium perchlorate. Mechanistic studies involving spectroscopic, quantum-yield and flash-photolysis measurements demonstrated that the photosensitized monomerization exclusively proceeds through electron transfer from the dimer to the triplet flavins complexed with Mg2+. The effects of magnesium perchlorate are compared with those on the chloranil-photosensitized monomerization and also with the effects of HClO4 on the flavin-photosensitized reaction.

Flavins↗