Biomedical subjects

H J Chung

Publications and source records attributed to H J Chung.

64 records · Page 4Linked to original sources

PubMed1991

EEG changes during recovery from acute severe neonatal citrullinemia.

We report our observations of serial clinical and EEG examinations in 3 neonates during recovery from acute severe encephalopathy due to citrullinemia. Their electroclinical picture closely resembles the clinical stages of experimental models of hyperammonemia in monkeys. The length of the EEG interburst interval, a quantitative measure of EEG background abnormality, correlated with elevated serum levels of ammonia and suggests that hyperammonemia itself is a key figure in the genesis of encephalopathy in this condition. Finally, the manner in which the EEG normalizes during recovery from hyperammonemia in this setting suggests that burst-suppression resembles an exaggerated regression to the discontinuity of the very premature infant.

Ammonia↗

PubMed1991

Significance of positive temporal sharp waves in the neonatal electroencephalogram.

We reviewed our computerized neonatal EEG database for records judged to display excessive positive temporal sharp waves (PTS) to determine their electroclinical associations and significance. Typical infants with excessive PTS were: (1) mature, with a mean conceptional age of 41.2 weeks, and (2) neurologically ill, judged by their high rate of associated EEG background abnormality (37 of 46; 80%) and clinical signs of encephalopathy (19 of 29; 66%). In comparison, healthy age-matched control infants never had excessive PTS. We consider an excess of PTS to be pathologic since they arise out of an abnormal EEG background in children exposed to potentially serious central nervous system illnesses and are associated with a high incidence of cerebral structural abnormalities (16 of 25; 64%). PTS may be comparable to the positive rolandic or vertex sharp waves in premature infants with periventricular injury of the deep white matter.

Brain Diseases↗

PubMed1989

Actinobacillus actinomycetemcomitans serotypes and leukotoxicity in Korean localized juvenile periodontitis.

Actinobacillus actinomycetemcomitans is though to play an important role in the pathogenesis of localized juvenile periodontitis (LJP). Preliminary data suggested that the serotype distribution of A. actinomycetemcomitans in Korea and the United States differ. This study evaluated A. actinomycetemcomitans prevalence, serotype distribution, and leukotoxicity in Korean LJP patients by culture, enzyme-linked immunosorbent assay, indirect immunofluorescence, and lactate dehydrogenase release from polymorphonuclear leukocytes exposed to A. actinomycetemcomitans. A. actinomycetemcomitans occurred in 75% of LJP lesions and 6% of normal sites with approximately equal distribution of serotype a, b, and c. Single serotypes were isolated from nine patients while three patients harbored two serotypes either in the same or different disease sites. A. actinomycetemcomitans leukotoxicity occurred in 22% isolates with a 69% prevalence. Individual sites harbored both leukotoxic and non-leukotoxic strains with no serotype association. The distribution of serotypes and leukotoxic strains of A. actinomycetemcomitans in Korean LJP patients differed from those reported in the United States. This suggests that serotype b may not be more important in the pathogenesis of LJP.

Actinobacillus↗

PubMed1989

[Tricalcium phosphate implant in periodontal defects--initial 3 months].

The present study was performed to evaluate the effect of tricalcium phosphate implant in human osseous defects. 4 intraosseous defects in 2 patients were treated with mucoperiosteal flap and tricalcium phosphate (TCP) implant and another 5 defects in the same patients were debrided only via mucoperiosteal flap. The healing response was evaluated clinically 10-12 weeks after treatment. More reduction in probing depth and more gains in probing attachment levels were observed in implanted sites than in control sites.

Bone Resorption↗

PubMed1986