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Biomedical subjects

Y Kohashi

Publications and source records attributed to Y Kohashi.

17 recordsLinked to original sources
PubMed1996

A new method using top views of the spine to predict the progression of curves in idiopathic scoliosis during growth.

STUDY DESIGN: A prospective longitudinal study of 51 patients with idiopathic scoliosis using spinal stereoradiographs was performed. The top view, which was obtained from stereoscopic anteroposterior and lateral radiographs, was analyzed for predicting the progression of spinal deformity. OBJECTIVES: To show that the top view facilitates prediction of curve progression in idiopathic scoliosis at the initial examination. SUMMARY OF BACKGROUND DATA: Four progression factors were set up using the top view and were analyzed statistically for predicting progression. No previous study has assessed this concept. METHODS: Fifty-one patients with idiopathic thoracic scoliosis or combined thoracic and lumbar scoliosis were studied longitudinally. There were 24 untreated patients and 27 patients treated with braces. Four potential progression factors were evaluated using the top view: 1) the ratio of the frontal size and the sagittal size in the top view, 2) the magnitude and direction of the vector describing the plane of maximum curvature in the thoracic spine, 3) the magnitude and direction of the vector describing the plane of maximum curvature in the lumbar spine, and 4) the balance of these vectors between the thoracic and lumbar curve. All cases were classified into five groups according to these four factors. RESULTS: The probability of the progression was evaluated statistically, and the prevalence of curve progression was found in each group. The probability of progression of a scoliosis curve increased according to the increase of these four factors. No significant difference was found between Cobb angle at the initial examination and that at skeletal maturity in untreated patients with a small risk of progression. The patients with a large risk of progression and who were treated with braces showed progression of curvature despite brace treatment. CONCLUSION: The present study has evaluated factors relating to progression in scoliosis using the top view. These results may help predict the risk of progression in idiopathic scoliosis.

Adolescent↗
PubMed1986

Suppressive effect of Escherichia coli on adjuvant-induced arthritis in germ-free rats.

Our previous finding, that germ-free F344 rats develop severe adjuvant-induced arthritis, whereas specific pathogen-free rats develop mild disease, prompted us to investigate the role of bacterial flora in promoting the development of this disease. Germ-free rats given Escherichia coli experienced disease suppression. Germ-free rats treated with 3 strains of Lactobacillus experienced an enhancement of the disease, although it was not significant. Germ-free rats treated with a combination of E coli and lactobacilli had disease suppression similar to that of E coli monoassociated rats. Thus, these findings suggest that E coli may play a dominant role in modulating the development of the disease in this particular strain of F344 rats, possibly through its lipopolysaccharide (as evidenced by positive results on limulus tests). These findings also suggest that microflora play an important role in modifying the development of joint disease.

Animals↗
PubMed1986

[Hepatic disorder during long-term intravenous hyperalimentation in adults].

Hepatic disorder during long-term intravenous hyperalimentation (IVH) in adults was studied. Fifty-one patients (30 males and 21 females) in whom IVH was performed for more than 60 days at Tenri Hospital from 1975 to 1984, were divided into 3 groups by change of indices which showed hepatic cellular injury (CII) and bile stasis (BSI). Namely, type I patients (33 cases) showed transient abnormality of indices, type II patients (14 cases) has continuous abnormal indices during IVH and type III patients (4 cases) were lethal due to hepatic failure. There were no differences in clinical feature among 3 groups. Incidence of metabolic complications during IVH in type II was significantly higher than in type I (p less than 0.05). All patients of type III were complicated by severe infectious diseases. Chief histological findings from 13 specimens (6 biopsies and 7 autopsies) were fatty degeneration of hepatocytes and fibrosis in the portal area with proliferation of bile ducts. Change of the portal area had closer relationship to the clinical severity of hepatic disorder than change of hepatocytes. BSI was more important than CII in inspection of clinical course and estimation of prognosis on hepatic disorder during IVH.

Aged↗
PubMed1986

Acute and chronic polyarthritis induced by an aqueous form of 6-O-acyl and N-acyl derivatives of N-acetylmuramyl-L-alanyl-D-isoglutamine in euthymic rats and athymic nude rats.

The analogs of N-acetylmuramyl-L-alanyl-D-isoglutamine (MDP), 6-O-stearoyl-MDP (L18-MDP), and N-(N-acetylmuramyl-L-alanyl-D-isoglutaminyl)-N-stearoyl-L-lysine (MDP-Lys-L18) and N-(2-tetradecylhexadecanoyl)-MDP (B30-MDP) induced acute polyarthritis in both euthymic rats and in athymic nude rats after a single or multiple systemic administrations of their aqueous forms; water-in-oil emulsions did not induce acute polyarthritis. MDP and the adjuvant-active analogs MDP-O-nBu (MDP butyl ester), N-(3-hydroxy-2-docosylhexacosanoyl)-MDP (BH48-MDP) and the adjuvant-inactive analogs [L18-MDP (L)] or MDP-Lys-L18 (L), which is 6-O-stearoyl-N-acetylmuramyl-L-alanyl-L-isoglutamine, or N-(N-acetylmuramyl-L-alanyl-L-isoglutaminyl)-N-stearoyl-L-lysine, did not induce disease, at the dosages used. Histological examination of the acute exudative inflammatory reactions around joints revealed hypertrophy of both synovial villi and tendon sheath, infiltration of polymorphonuclear leukocytes (PMN) and fibrin deposition of the affected joint spaces. Most of these lesions rapidly subsided after cessation of the adjuvant injections. During multiple systemic injections of acyl-MDPs, this acute arthritis became chronic in euthymic rats but not in athymic nude rats; the chronic polyarthritis consisted of mononuclear cell infiltration and proliferation of the connective tissue growth and severe new bone formation of the shaft of the bone. It remains uncertain whether chronic polyarthritis results from the repeated flare of acute inflammatory reactions to the continuing stimulation of the adjuvants or whether it may require some immunologic process to such exogenous substances as bacterial fragments or autoantigens modified by exogenous substances such as type II collagen.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1985

Reverse effect of gram-positive bacteria vs. gram-negative bacteria on adjuvant-induced arthritis in germfree rats.

Germfree (GF) F344 rats developed severe adjuvant-induced arthritis with a 100% incidence after a single intradermal injection of heat-killed Mycobacterium bovis (BCG). Specific pathogene-free (SPF) rats developed less severe arthritis with a lower incidence. The rats colonized with Escherichia coli or Bacteroides developed mild disease comparable to that in SPF rats. The rats colonized with Bifidobacterium, Propionibacterium acnes, Lactobacillus casei, L. fermentum, L. murini, and L. acidophilus developed more severe disease than that in GF rats. Furthermore, the rats colonized with a mixture of E. coli and the above lactobacilli developed very mild disease similar to that in SPF rats. These results suggest that gram-negative bacteria, such as E. coli and Bacteroides, may suppress the disease, possibly through their lipopolysaccharides, and may be responsible for the lower susceptibility of SPF rats; gram-positive bacteria, such as Bifidobacterium, P. acnes, and lactobacilli, may enhance the disease, possibly through their peptidoglycans; and E. coli may play a dominant role in modulating the development of adjuvant-induced arthritis.

Animals↗
PubMed1984

Reduction of left ventricular size following oxygen inhalation in patients with coronary artery disease as measured by biplane coronary cineangiograms.

Left ventricular size is one of the major determinants of myocardial oxygen consumption, therefore if oxygen inhalation reduces myocardial oxygen demand, such might be beneficial in the treatment of acute myocardial infarction. Routine diagnostic biplane left coronary cineangiograms were obtained during air or oxygen breathing in 11 patients with old myocardial infarction or angina pectoris. Coordinates of the points on the left coronary artery were measured and throughout one cardiac cycle frame by frame. The spatial distance (segment length: L) between any two of these points was calculated. Segment length at R wave on the electrocardiogram (LECG R) and minimum value (Lmin) for each segment were calculated. Arterial pO2 was elevated by oxygen breathing from 91 +/- 4 (+/- SE) to 427 +/- 18 mmHg. Left ventricular segment length was significantly reduced by oxygen breathing: LECG R being reduced following oxygen breathing from 62.3 +/- 3.0 to 60.6 +/- 3.0 mm (a decrease of 3.3 +/- 0.8%) and Lmin also being reduced from 55.9 +/- 2.8 to 54.4 +/- 2.8 mm (a decrease of 3.1 +/- 1.0%). These figures indicate that left ventricular size was reduced. Reduction in left ventricular size through oxygen inhalation, by reducing myocardial oxygen demand, should therefore be beneficial in coronary artery disease.

Adult↗
PubMed1983

The failure of oxygen breathing to decrease the myocardial contractile force in denervated dogs.

This study was done to discover whether or not the oxygen-induced depression of sympathoadrenal activity contributes to a reduction of myocardial contractile force during oxygen breathing. In 10 open-chest dogs, myocardial contractile force was measured using a myocardial strain gauge arch during air and oxygen breathing before denervation (intact heart) and after bilateral vagotomies, sympathectomies and adrenalectomies with the intravenous administration of propranolol, phenoxybenzamine and atropin (denervated heart). One hundred percent oxygen breathing caused similar increases in arterial pO2 in both the intact (from 94 +/- 10 to 442 +/- 25 mmHg) and the denervated dogs (from 113 +/- 11 to 456 +/- 15 mmHg). Coronary blood flow measured at the left anterior descending coronary artery was reduced by oxygen breathing from 28.4 +/- 3.4 to 21.7 +/- 2.3 ml/min in the intact dogs, and from 19.4 +/- 3.4 to 14.9 +/- 2.6 ml/min in the denervated dogs. Myocardial contractile force was significantly reduced by oxygen breathing in the intact dogs (a reduction of 5.8 +/- 1.4%). In the denervated dogs, on the other hand, no significant changes in myocardial contractile force was seen. This study suggests that the reduction in myocardial contractile force is mediated through sympathoadrenal activity, and thus, is abolished by sympathoadrenal blockade.

Adrenalectomy↗
PubMed1981

Myocardial contractile force at high coronary arterial oxygen tension in dogs.

In 34 mongrel dogs, the left anterior descending coronary artery was perfused with the dog's own femoral arterial blood at a constant flow rate and the myocardial contractile force was measured using a myocardial strain gauge arch. When the femoral arterial blood was oxygenated (pO2 61.7 kPa (463 mmHg)) using an artificial lung, so that the perfused myocardium became hyperoxic, the myocardial contractile force was increased by 11.1 +/- 2.3%. When the perfusion rate was reduced by approximately 20%, there was a smaller increase in myocardial contractile force, 8.0 +/- 2.3%. If, in addition, oxygen inhalation was performed the myocardial contractile force decreased by 4.1 +/- 2.1%. In 10 mongrel dogs, the carotid arteries were perfused at a constant flow rate with femoral arterial blood from a donor dog. Oxygen inhalation by the donor dog caused a reduction in the myocardial contractile force of the experimental dog of 5.9 +/- 1.6%. It is suggested that oxygen has a direct effect in increasing myocardial contractile force. This increase is counteracted by oxygen-induced coronary vasoconstriction in some part and by a neurohumoral effect or suppression of chemoreceptor activity.

Animals↗
PubMed1981

[Change of left ventricular segment length by nitroglycerin measured by biplane coronary cineangiography in man (author's transl)].

Left ventricular size at different portions was evaluated following the administration of nitroglycerin to find whether there is any regional difference in the amount of shortening. In 6 patients with old myocardial infarction, biplane coronary cineangiograms were obtained before and after sublingual administration of nitroglycerin of 0.3 mg. The coordinates of the bifurcations of the left coronary artery at multiple sites were measured on the postero-anterior and lateral films and the spatial lengths (L) between any paired two points were calculated frame by frame covering one cardiac cycle. The maximum length (Lmax) was 63.2 +/- 3.1 (SE) mm before nitroglycerin as a whole and was 61.4 +/- 2.9 mm after nitroglycerin, showing no significant change. The minimum length (Lmin) also showed no significant change after nitroglycerin; from 56.1 +/- 2.9 to 54.9 +/- 2.6 mm. However, at the free wall, Lmax after nitroglycerin was reduced by 4.5 +/- 2.5%, and Lmax at the anterior septum was also reduced by 3.0 +/- 1.3%. Lmax at the base was unchanged after nitroglycerin. Lmin at the free wall and at the anterior septum were also reduced after nitroglycerin, 4.4 +/- 2.6 and 2.9 +/- 1.2%, respectively, and it was unchanged at the base. Since a reduction in the left ventricular size is effective in reducing myocardial oxygen demand and is effective in treating myocardial ischemia, it was suggested that nitroglycerin is more effective in relieving ischemia at the free wall and septum and less effective at the base.

Cineangiography↗
PubMed1980

Increases in coronary vascular resistance related to high arterial oxygen tension in dogs.

It is known that oxygen inhalation induces coronary vessel constriction as well as brings about a reduction in myocarial oxygen consumption. The present study was performed to clarify whether or not this constriction of the coronary vessels resulting from oxygen is secondary to the reduction in myocardial oxygen consumption. The regional myocardium in 12 mongrel dogs was perfused with femoral arterial blood at a constant rate of flow. While maintaining myocardial oxygen consumption equal by adjusting heart rate, coronary vascular resistance was compared under the two following conditions: 1) perfusion of the coronary artery with the dog's own femoral arterial blood (pO2 : 95 +/- 14 mmHg) and 2) perfusion with blood with a high level of oxygen tension (pO2 : 497 +/- 56 mmHg). Coronary vascular resistance was increased (p < 0.001) from 3.00 +/- 1.25 to 3.36 +/- 1.28 mmHg/ml/min by incresing the pO2 in the perfusing blood, even though myocardial oxygen consumption was kept at the same level. This increase in coronary vascular resistance resulting from the increase in oxygen tension was independent of the coronary perfusion rate as well as independent of the presence or absence of myocardial ischemia. This suggests that coronary vasoconstriction due to oxygen is not secondary to decreases in myocardial oxygen demand.

Animals↗