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Biomedical subjects

H S Chung

Publications and source records attributed to H S Chung.

7 recordsLinked to original sources
PubMed1991

[Effect of shift interval for the clinical nurse with respect to circadian rhythm].

Circadian rhythm is entrained in the 24-hour time interval by periodic factors in the environment, known as zeitgeber. But most rotating work schedules are outside the range of the entrainment of the pacemaker timing the human circadian sleep-wake cycle. It has been postulated that physiological and emotional disturbances occur in most human functions when the circadian rhythm is disturbed. So application of circadian principles to the design of shift schedules can aid in maintaining the temporal integrity of the circadian system and thereby minimize for the shift worker any detrimental consequences of circadian disruption. This study was a quasi-experimental study to test the effect of shift intervals for the clinical nurse on the circadian rhythm. Twenty nurses newly employed in general units of two hospitals were selected as an experimental group and twelve college nursing students as a control group. Both groups were selected according to an established criteria using a purposive sampling technique. Ten subjects were assigned to a weekly shift group and another ten to a biweekly shift group engaged in a semi-continuous shift schedule (sunday off) with a backward direction; that is, morning-evening-night shift. The control group worked a morning shift for 42 days. Oral temperature rhythm, waking time, sleep-wake cycle, fatigue, and mental performance were measured during the experimental period. The data collection period was from April 30, 1990 to June 10, 1990. MANOVA, paired t-test, ANOVA, and Student Newman Keuls method were used for statistical analysis. The results are summarized as follows. 1. Phase delay in the acrophase of temperature rhythm was shown according to the backward rotating shift. A complete adaptation to work on the night shift was achieved between the sixth and ninth day of the night shift. 2. There was no difference in either waking time or sleep-wake cycle according to the duration of the working day for every shift group. Significant difference was found in the waking time and the sleep-wake cycle for subjects on the morning, evening, and night shift in both of the shift groups (weekly shift group: lambda = 0.121, p less than 0.01, lambda = 0.112, p less than 0.01, biweekly shift group: lambda = 0.116, p less than 0.01, lambda = 0.084, p less than 0.01). 3. There was no difference in fatigue between the first working day and the last working day for the control group and for the biweekly shift group.(ABSTRACT TRUNCATED AT 400 WORDS)

Analysis of Variance↗
PubMed1991

Abnormal muscle response in microvascular decompression of hemifacial spasm.

In 1976, Jannetta et al, suggested that microvascular compression caused by arteries and veins crossing the root entry zone of the facial nerve, was the major etiology of hemifacial spasm (HFS). Surgical treatment has become a major trend. Microvascular decompression (MVD) with teflon patches has a high cure rate. However, the possible occurrence of multiple vessel compression makes it difficult to decide which of these vessels are responsible for the symptom during operation. Recently, a method of abnormal EMG was elaborated upon by Møller and Jannetta in 1987, to ensure the quality of MVD intraoperatively. In this study, we report 6 cases who underwent the procedure successfully. After general anesthesia and muscle relaxation, the abnormal EMG was not suppressed. When the offending vessel was lifted up from the facial nerve, the abnormal EMG disappeared immediately. In each case, postoperative improvement of facial spasm correlated with intraoperative abnormal EMG changes. This method is not only able to guide the surgeon to the vessel that induces HFS but also guarantees the quality of MVD.

Adult↗
PubMed1989

[The changes of the orofacial muscle activity induced by the lip forces in subjects with normal occlusion].

This study was intended to investigate whether lip exercise affect the activities of the lips, tongue, digastric and masseter muscles and to understand the functional interrelationship between them. As the forces of maximum lip grimace was reduced to slight lip seal gradually, the electromyograph was taken from 9 conscious human adults with normal occlusion in the upper and lower lips, tongue, digastric and masseter muscle using surface electrodes, especially, newly designed subminiature surface electrodes which was attached directly to the tongue. The results were as follows. 1. During induced maximum lip grimace in the mandibular rest position, there're prominent increase of EMG activity in the upper and lower lips, tongue and digastric muscle 1714 mu v, 2787 mu v, 2142 mu v and 623 mu v, respectively, but there was little activity in the masseter muscle, 129 mu v. The force level induced by maximum grimace of the lips was about 110g when the force transducer was positioned between upper and lower lips in the incisor area. 2. As the lip forces were reduced gradually, EMG activities of the lips, tongue and digastric muscles were decreased definitely with certain tendency, but there was no change in the masseteric EMG activity. Above mentioned results suggest that (1) lip exercise can promote the activities of the lips, tongue and digastric muscles but cannot change the activity of the masseter muscle and (2) masseteric muscle activity seems to be independent of the lips and the tongue but digastric muscle activity is related more closely to them through lip exercise in the subjects with normal occlusion.

Adult↗
PubMed1977

Abnormalities of the immune system in children with neuroblastoma related to the neoplasm and chemotherapy.

Children with localized and metastatic neuroblastoma were studies to determine their immune status at the time of diagnosis and while they were receiving intensive intermittent chemotherapy; Investigations included leukocyte and differential counts, delayed hypersensitivity response, quantitative serum immunoglobulins, percentages of T and Fc receptor lymphocytes, PHA-induced mitogenesis, and antibody-and PHA-dependent cellular cytoxicity. Abnormalities related to the neoplasm at diagnosis were limited to depressed leukocyte and lymphocyte counts and increased concentrations of serum IgM in patients with metastases to bone marrow and other sites. No abnormalities were observed in those with localized tumors. Intermittent chemotherapy of metastatic neuroblastoma caused immunosuppression. Effects were most marked during five-day courses of chemotherapy; they included abrogation of DH and decreased leukocyte and lymphocyte counts and percentages of Fc receptor lymphocytes. Recovery of DH with partial recovery of leukocyte and lymphocyte counts was observed three weeks, later, prior to the next course, We conclude that both metastatic tumor and chemotherapy cause abnormalities of the immune system in children with neuroblastoma.

Antibodies, Neoplasm↗