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Biomedical subjects

K Chin

Publications and source records attributed to K Chin.

At least 145 records · Page 8Linked to original sources
PubMed1989

Analysis of survival in patients with pulmonary atresia and intact ventricular septum treated surgically.

The epidemiology of 98 children who underwent surgical intervention for pulmonary atresia and intact ventricular septum is presented. Sixty-one (62.2%) of the children died. Survival time from the date of the first operation ranged from 0 to 17.76 years. Analysis of the survivors revealed that an estimate of the probability of surviving for two years is 47% (95% confidence limits of 37%, 57%). An estimate of the median survival time is 1.43 years. In a Cox proportional hazards model, using survival time in days as the outcome variable (n = 73, using complete data), operative weight at first operation (P = 0.0019), right/left ventricular pressure ratio (P = 0.0185), and absence of ventriculo-coronary arterial connections (P = 0.0362) were identified as significant predictors of survival.

Adolescent↗
PubMed1989

Linked markers flanking the gene for multiple endocrine neoplasia type 2A.

The inherited cancer syndrome multiple endocrine neoplasia type 2A (MEN2A) has recently been mapped to chromosome 10. We have typed 29 families with this disorder with DNA markers from the pericentromeric region of chromosome 10. Two markers, RBP3 and MCK2, were tightly linked to the MEN2A gene at recombination fractions of less than 3%. Multipoint analysis of the linkage data suggests that the gene is located within a 3-cM interval defined by the markers RBP3/MCK2 on one side and TB14.34 on the other. No evidence for locus heterogeneity was detected in any of the 27 families from 14 countries who were informative for the markers tested. The data confirm and refine the original assignment and provide the basis for presymptomatic screening for this disorder.

Chromosome Mapping↗
PubMed1989

Breathing during sleep with mild hypoxia.

To investigate ventilatory response to mild hypoxia during non-rapid-eye-movement sleep, we administered approximately 16% O2 (which corresponds to concentrations found in commercial high altitude air craft) to 12 normal subjects by using a Venturi mask, which did not alter the breathing pattern during this study. Under mild hypoxia, inspiratory minute ventilation during sleep showed an initial rapid increase (P less than 0.001) but then declined significantly (P less than 0.001) and stabilized. Stable levels differed among individuals and, compared with those measured before hypoxia, were significantly lower in some subjects, higher in one, and essentially unchanged in the others. The initial rapid increase in minute ventilation after mild hypoxia during sleep correlated with the respective values of hypoxic ventilatory response during the awake state (P less than 0.01), but the final lowered levels did not. We conclude that the ventilatory response after mild hypoxia during sleep is biphasic and hypoxic depression exerts considerable influence on ventilation under mild hypoxia during sleep. So we should take hypoxic depression into consideration to evaluate the response to hypoxia during sleep.

Adult↗
PubMed1989

[Noninvasive ventilatory support on chronic respiratory failure with hypoventilation].

Chest negative pressure ventilation (CNPV) and intermittent positive pressure ventilation (IPPV) through a nose mask were used for ventilatory support of 4 patients with chronic respiratory failure due to old tuberculosis (2 patients), chronic pulmonary emphysema, and kyphoscoliosis (VC, 0.91 +/- 0.16 L; %VC 31.2 +/- 3.2; FEV1.0, 0.62 +/- 0.19 L). These ventilatory supports were used for relief of chronic arterial CO2 retention, weaning from the mechanical ventilation, therapy for the acute exacerbation on the chronic respiratory failure, and the relief of the respiratory muscle fatigue. After CNPV and IPPV through a nose mask, PaCO2 showed a significant fall from 75.7 +/- 14.8 Torr to 60.2 +/- 12.3 Torr (p less than 0.01). All patients showed improvement of clinical symptoms. Two patients have continued CNPV at home on a regular basis. We conclude that CNPV and IPPV through a nose mask significantly improve hypoventilation and quality of life in some patients with chronic respiratory failure.

Adult↗
PubMed1989

[Evaluation of respiratory disability in patients of respiratory diseases using relationships between ventilatory drive, ventilation and thoracic pump function during exercise].

We studied the parameters of breathing control during exercise in patients with respiratory diseases for the evaluation of respiratory disability. The ventilatory drive during the same load exercise was increased in patients with respiratory diseases compared with that in normal subjects. In addition, the ratio of ventilation to ventilatory drive during exercise was decreased in patients with respiratory diseases. Impairment of rapid thoracic movement was suggested to be one of the mechanical limitations for ventilation in these patients, based on the findings of smaller esophageal pressure fluctuation during maximum ventilation of 40 respirations per minute than that in normal subjects. Flow at 0.1 sec after initiation of inspiration was designated V0.1. The increase of the ratio of V0.1 at rest to that at maximum voluntary inspiration (V0.0 (rest)/V0.1 (max)) indicate the grade of respiratory disability showing the impossibility of rapid movement of thorax as a parameter of thoracic pump function. It was recognized that the decrease of VE/P0.1 during incremental exercise indicated ventilatory insufficiency.

Exercise Test↗
PubMed1989

[Well-differentiated adenocarcinoma of the papilla of vater--report of a case].

Reported is the case of a 64-year-old female who was admitted to our clinic because of hyperamylasemia. Duodenal endoscopic examination revealed a tumor at the papilla of Vater. A biopsy specimens taken from the top of the tumor showed a well-differentiated adenocarcinoma. Under the diagnosis of cancer of the papilla of Vater, pancreaticoduodenectomy was performed. The first histological diagnosis was carcinoma in adenoma, but from the results of nucleus-gland ratio examined from 6 parts of the "adenoma", all of which were over 0.50, we finally concluded this case as de nove well-differentiated adenocarcinoma, and not carcinoma in adenoma. Thus, there is a possibility that past reports of adenoma or carcinoma in adenoma of the papilla of Vater might contain de novo well-differentiated adenocarcinoma.

Adenocarcinoma↗
PubMed1987

Is endoscopy hazardous to your liver?

In a survey of a gastrointestinal endoscopy society, 92 members (84%) filled out a questionnaire and donated serum specimens for testing for hepatitis B markers and alanine aminotransferase. The frequency of serologic evidence of exposure to hepatitis B was only slightly higher than that seen in the general population and comparable to that reported in "low-risk" health-care workers. Overall, 12% had markers of previous hepatitis B exposure and 3% had an abnormal aminotransferase determination. There was no correlation between hepatitis B exposure and endoscopic experience.

Adult↗
PubMed1987

Effects of head restraint on signal detectability in simultaneous and successive vigilance tasks.

Dittmar, Warm, and Dember (1985) suggested that visual parallax may lead to declines in perceptual sensitivity over time in spatial vigilance tasks involving comparative judgments. The present study tested this possibility by restraining subjects' head movements during a 1-hr vigil in which comparative (simultaneous task) or absolute (successive task) judgments of line length were necessary for signal detection. Under free-viewing conditions, perceptual sensitivity declined over time with both types of tasks. Head restraint eliminated the sensitivity decrement in both cases. The results highlight signal quality as a crucial determinant of perceptual decrements in sustained attention.

Attention↗
PubMed1986

Purification of murine erythropoietin produced in serum-free cultures of erythroleukemia cells.

We previously documented that several erythroleukemia cell lines released factors that stimulated erythropoiesis in vivo and in vitro. A simple five-step scheme has been devised that allows purification of this erythropoietic activity to apparent homogeneity. The methods employed included lectin affinity chromatography (wheat germ agglutinin), gel filtration (ultro gel ACA44), ion exchange, hydroxylapatite, and high performance liquid chromatography. Following polyacrylamide gel electrophoresis, biologic activity was recovered in an area corresponding to a molecular weight of 35,000 daltons. Silver staining of a polyacrylamide gel after electrophoresis of our most purified preparation revealed a single band at 35,000 daltons.

Animals↗
PubMed1985

Paradoxical deterioration of left ventricular asynergy after administration of nitroglycerin.

The effects of nitroglycerin on segmental asynergy were studied by 2-dimensional echocardiography. Forty-five patients with coronary artery disease and segmental wall motion abnormality at rest were examined, 31 with Q-wave and 14 with only ST-T abnormalities. Left ventricular (LV) echocardiograms were recorded from the LV apex in 4 planes, obtained by systematically rotating the transducer at 45 degrees intervals around the mitral office, using a mechanical device. Sixteen LV segments were analyzed in each patient on real-time display by 2 observers independently. The wall motion analysis was classified as normal, hypokinetic, akinetic or dyskinetic. Of 720 segments, 596 were agreed on by 2 observers in the assessment of wall motion before and after administration of nitroglycerin: 334 segments (56%) showed no change in wall motion, 206 (35%) showed improvement of wall motion and 56 (9%) showed worsening of myocardial asynergy after nitroglycerin. These data suggest that administration of nitroglycerin may result in unexpected worsening of segmental asynergy. This may be secondary to an adverse effect of a decrease in perfusion pressure in critically occluded arteries or may represent a coronary steal phenomenon.

Aged↗