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Biomedical subjects

M Su

Publications and source records attributed to M Su.

11 recordsLinked to original sources
PubMed1991

Does prestretching stainless-steel wire have any clinical significance?

Clinical parameters of prestretch and tension forces placed on stainless-steel wire by 20 oral and maxillofacial surgeons were obtained. Unstretched wire was clinically as tough or tougher than prestretched wire of a similar gauge. Both prestretched and unstretched wires, twisted to their maximum, loosened when under tension. As the prestretch forces increased, the clinical strength of the wire diminished.

Analysis of Variance↗
PubMed1991

Ventilatory and cardiometabolic responses to unilateral sanding in elderly women with ischemic heart disease: a pilot study.

This study was undertaken to investigate how 8 elderly women with ischemic heart disease would respond to a unilateral sanding activity. Three ventilatory measures-expiratory tidal volume, respiratory rate, and expiratory volume--and four cardiometabolic measures--metabolic equivalent, systolic blood pressure, heart rate, and pressure rate product--were continuously recorded during the sanding activity. The two independent variables were angle of the sanding board and sanding velocity. The activity was graded to yield five conditions: (a) sitting at rest; (b) 0 degrees at 15 cycles per min (cpm); (c) 0 degrees at 30 cpm; (d) 15 degrees at 15 cpm; and (e) 15 degrees at 30 cpm. The findings indicated that increasing the angle of the board while holding the velocity constant did not always increase the mean values of the ventilatory and cardiometabolic measures. However, increasing the velocity while holding the angle constant always increased the mean values of the dependent variables. The data also indicated that the metabolic equivalent reached during the sanding activity was no greater than 2, which corresponds to a light activity, such as playing a musical instrument. Replication of the study with a larger sample size may further elucidate the behavior of these two functions during a graded sanding activity. In the present study, a unilateral sanding activity by elderly patients with cardiac impairment was shown to provide valuable data on ventilatory and cardiometabolic functions. The study also demonstrated that a unilateral sanding activity can be safely used as a graded activity in occupational therapy for the cardiac rehabilitation of elderly women.

Activities of Daily Living↗
PubMed1991

[Effect of diethyldithiocarbamate on interleukin 2 production of patients with oral lichen planus and its clinical therapeutic efficacy].

Diethyldithiocarbamate (DTC), a biological augmenting agent specific for T cells, was applied to treat patients with incipient oral lichen planus (OLP) who had been refractory to traditional therapy. DTC was administered orally (5 mg.kg-1, twice a week) for at least 3 months. Interleukin 2 (IL-2) production and lymphocyte proliferation of peripheral blood mononuclear cells (PBMC) were measured before and after the treatment. The bioactivity of IL-2 was determined by the use of IL-2 dependent cell line CTLL-2 and human recombinant IL-2. The results indicated that both IL-2 production of PBMC and lymphocyte proliferation increased (P less than 0.01). Clinical symptoms were improved significantly. The effective rate in 30 patients was 86.7%. It is suggested that the mechanism involves that DTC improves the cellular immunity of the patients.

Adult↗
PubMed1990

[Analysis of mononuclear cell subsets infiltrated and DR-positive epithelial cells in autoimmune thyroid diseases].

Specimens of thyroid tissue from 37 cases of autoimmune thyroiditis (AT), 13 cases of thyrotoxicosis accompanied with thyroiditis (TTOT), and 23 cases of Graves' disease (GD) were analyzed by immunohistochemistry with monoclonal antibodies. The majority of infiltrating mononuclear cells were learnt to be T cells. T+4 cells were abundant in lymphoid follicles and many T+8 cells were noticed in those areas with advanced destruction. B lymphocytes were predominantly located at the germinal centers. Most importantly, DR-positive thyroid epithelial cells were significantly increased with intense lymphocytes infiltration and severe destruction of the thyroid architecture. The percentage of T cell subpopulations, B cells, macrophages were somewhat similar. Anyhow, the increase of total number of infiltrating cells and the extent of inflammatory injury were remarkable in GD, TTOT and AT. The results support the idea that some GD cases may further develop in to autoimmune thyroiditis later.

CD4-Positive T-Lymphocytes↗
PubMed1989

Lack of alveolar O2 during lung reperfusion does not decrease edema formation.

We previously reported that pulmonary arterial occlusion for 48 h followed by 4 h of reperfusion in awake dogs results in marked edema and inflammatory infiltrates in both reperfused and contralateral lungs (Am. Rev. Respir. Dis. 134: 752-756, 1986; J. Appl. Physiol. 63: 942-950, 1987). In this experiment we study the effects of alveolar hypoxia on this injury. Anesthetized dogs underwent thoracotomy and occlusion of the left pulmonary artery. Twenty-four hours later the dogs were reanesthetized, and a double-lumen endotracheal tube was placed. The right lung was continuously ventilated with an inspiratory O2 fraction (FIO2) of 0.35. In seven study animals the left lung was ventilated with an FIO2 of 0 for 3 h after the left pulmonary artery occluder was removed. In six control animals the left lung was ventilated with an FIO2 of 0.35 during the same reperfusion period. Postmortem bloodless wet-to-dry weight ratios were 5.87 +/- 0.20 for the left lower lobe and 5.32 +/- 0.12 for the right lower lobe in the dogs with hypoxic ventilation (P less than 0.05 for right vs. left lobes). These values were not significantly different from the control dog lung values of 5.94 +/- 0.22 for the left lower lobe and 5.11 +/- 0.07 for the right lower lobe (P less than 0.05 for right vs. left lobes). All values were significantly higher than our laboratory normal of 4.71 +/- 0.06. We conclude that reperfusion injury is unaffected by alveolar hypoxia during the reperfusion phase.

Animals↗
PubMed1988

Dimethylthiourea does not ameliorate reperfusion lung injury in dogs or rabbits.

We previously demonstrated that in vivo reperfusion of a dog lung after 48 h of pulmonary arterial (PA) ischemia results in pulmonary edema with a significant infiltrate of polymorphonuclear leukocytes. We hypothesized that the injury resulted from production of hydroxyl radical by activated neutrophils. In the current study, we attempted to prevent the injury in both dogs and rabbits with dimethylthiourea (DMTU), a scavenger of hydroxyl radical. After 48 h of left PA occlusion in 18 dogs, DMTU was administered to 9 animals and 9 were not treated. The occlusion was then released, and the dogs were killed 4 h later. Reperfusion resulted in a drop in leukocyte count and left lung edema, but there was no difference between treated and untreated animals. The wet-to-dry ratios of the lungs in the treated group were 5.76 +/- 0.44 (SE) on the reperfused left side and 4.50 +/- 0.06 (P less than 0.05) on the right side. In the untreated groups the comparable ratios were 5.73 +/- 0.31 and 4.92 +/- 0.10 (P less than 0.05 for right vs. left). Histological examination revealed significant differences between the right and left lungs in the extent of intra-alveolar granulocytes and macrophages but did not reveal differences between the treated and untreated animals. To ensure that neither the model nor the lack of response to DMTU was species specific, we then developed a rabbit model of reperfusion edema.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1975

Vasomotor nerve control of isolated arteries and veins.

In order to compare neuro-effector function in different blood vessels, frequency-response relationships were determined for the following preparations: 1)Isolated rings of the proximal saphenous, distal saphenous and ear arteries, the parietal branch of the internal iliac vein and the small saphenous vein from the rabbit, 2) spiral strips of the rabbit pulmonary artery and 3) longitudinal preparations of the rat portal vein. In each rabbit tissue only one low (less than or equal to 4 Hz) and one high (larger than or equal to 8 Hz) transmural nerve stimulation frequency was applied until steady state responses were obtained and these were expressed as a percentage of a maximum response to exogenous noradrenaline (NA) applied in each experiment. The general shape of the frequency-response curves was similar, but differences in steepness and amplitude of the maximum neurogenic response relative to exogenous NA were found. The steepness of the frequency-response relationships of the veins tended to be greater than those of the arteries. It appears that factors such as close neuro-muscular contacts, presence of terminal nerve fibres within the media and the operation of mechanisms for myogenic propagation of activity contribute to the effectiveness of neurogenic vascular control as revealed by frequency-response curves. In vivo, geometrical factors can greatly augment the hemodynamic significance of the observed differences.

Animals↗
PubMedDate not supplied

Ibuprofen improves cerebral blood flow after global cerebral ischemia in dogs.

In a canine model of global cerebral ischemia, 6 dogs received a saline placebo prior to the event and 5 received 12.5 mg/kg ibuprofen. Cerebral venous outflow from the confluence of the sagittal and transverse sinuses, systolic and diastolic arterial pressure, cardiac output, pH, Paco2, Pao2, and arterial and sagittal sinus thromboxane B2 and 6-keto-PGF1 alpha were measured at intervals up to 120 minutes thereafter. Postischemic cerebral hypoperfusion was significantly improved in the ibuprofen pretreatment group. Control dogs showed significant increases in sagittal sinus postischemic thromboxane B2 concentrations, but pretreated dogs showed nearly complete inhibition of postischemic thromboxane B2 production. Pretreated dogs also had significantly lower levels of 6-keto-PGF1 alpha from the sagittal sinus. There were no significant differences in the other variables at any interval. We conclude that ibuprofen ameliorates postischemic cerebral hypoperfusion, and that this improvement is associated with decreased sagittal sinus levels of thromboxane B2 and 6-keto-PGF1 alpha.

6-Ketoprostaglandin F1 alpha↗