Biomedical subjects
Publications and source records attributed to K Y Chang.
A growing understanding of the diversity of structures and biological functions of DNA and RNA, coupled with progress in synthetic and spectroscopic techniques, have allowed remarkable progress in NMR studies of nucleic acids. Here we review novel principles of nucleic acid structure and recognition revealed by these studies and highlight opportunities for future progress.
It has been a common observation that children with supracondylar fracture of the humerus tend to demonstrate hyperextensibility of their elbow joints. In this study, we measured and compared the degree of hyperextension of the uninjured elbow of children less than sixteen years old who sustained either a supracondylar or a distal radial fracture. We concluded that children with higher degree of hyperextension in the elbow are more likely to sustain a supracondylar fracture than a distal radius fracture during a fall on the outstretched hand.
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BACKGROUND AND STUDY AIMS: Information about the appropriate endoscopic treatment of gastric variceal bleeding is sparse. We therefore designed a prospective and randomized study to evaluate and compare efficacy and complication rates of two agents, hypertonic glucose water (50% GW) and sodium tetradecyl sulfate (STS), in treating acute gastric variceal bleeding after esophageal varix eradication. PATIENTS AND METHODS: Of 51 patients with advanced cirrhosis of the liver (Child's C), with acute gastric variceal bleeding initially evaluated, 25 patients were randomized to receive 1.5% STS and 26 to receive 50% glucose water. Treatment was aimed at achieving initial and permanent hemostasis by variceal eradication. RESULTS: Control of acute gastric variceal bleeding was achieved in 80% of the STS group and 92% of the GW group. The rebleeding rate in the STS group was 70%, while in the GW group it was 30% (P < 0.05). Overall, obliteration was achieved in only 32% of the STS group and 81% of the GW group during admission (P < 0.05). There was a trend toward a higher gastric ulcer rate in the STS group compared with the GW group (92% vs. 30%; P < 0.05). The rebleeding control rate and permanent hemostasis rate in the GW group (70%, 54%) were also significantly higher than in the STS group (21%, 12%; P < 0.05; P < 0.05). The hospital mortality for the STS group was 50%, and for the GW group 30%. CONCLUSION: Treatment with hypertonic glucose water in gastric vericeal bleeding was superior to treatment with STS in controlling bleeding and in achieving vericeal obliteration, less rebleeding, and a lower complication rate. The results of this study suggest that hypertonic glucose water is a clinically effective, easily available, and safe sclerosing agent.
Transferrin binding protein (TfBP), a glycoprotein, is originally purified from the chicken oviduct. Recently, TfBP has been revealed as a novel transferrin binding protein, structurally related to the chicken heat shock protein 108. The physiological function of this protein, however, has not yet been established. Antiserum to TfBP was found to stain selectively transferrin- and iron-rich oligodendrocytes of the normal chicken brain, suggesting a role for this protein in connection with transferrin and iron storage in these cells. In this study, we further demonstrate a TfBP-immunoreactivity in the chicken respiratory tract mucosa, where transferrin is known to be present and have antioxidant and antibacterial properties. A strong TfBP immunoreactivity was revealed in certain regions of the respiratory tract. In the trachea and bronchi, TfBP-immunoreactive product was localized specifically to the mucous gland cells, whereas ciliated epithelial cells were negative. In the lung, TfBP immunoreactivity was mostly confined to the parabronchi and atria. The immunoreactive products were found in the cytoplasm of the epithelial cells lining the parabronchial and atrial walls. These findings suggest that the presence of TfBP in the airway mucosa may be a necessary condition for transferrin concentration in the extracellular milieu of the respiratory tract.
In Taiwan, spontaneous oesophageal rupture is uncommon but the outcome is often lethal because of failure to make an early diagnosis. We have analysed clinical data, management and the risk factors that affect mortality for a consecutive series of 11 patients who had spontaneous oesophageal perforation between 1983 and 1994. The primary symptom was chest or abdominal pain, which was present in 100% of patients; 91% of patients had abnormal chest x-ray (63% pleural effusion, 46% pneumomediastinum, 37% subcutaneous emphysema). In our series of patients the lower thoracic area was the most common location of the perforation (80% of patients. There were no statistically significant differences in mortality due to age, underlying disease, perforation size, location or surgical methods. A poor prognosis seems to be correlated with the time elapsed between the perforation and treatment (especially if > 72 hours) (p < 0.05), respiratory failure (p < 0.05), and heavy contamination of the mediastinum (p < 0.05). The clinical findings depend on the location and time of perforation. History, chest x-ray and oesophagogram are the most useful diagnostic tools. Early diagnosis and treatment are mandatory for these patients.
From February 1979 to May 1994, 18 cases of colonic tuberculosis were detected by colonscopy at Chang Gung Momorial Hospital, Linkou Medical Center. There were 10 males and 8 females, with mean age of 43.6. In ten, the diagnosis was confirmed histologically or bacteriologically in colonic biopsy material and post-operated lymph nodes. The remaining 8 patients was suspected on colonoscopy, and had good response to antituberculous therapy. The major symptoms were abdominal pain (83%), diarrhea (67%), and body weight loss (61%). Average duration from symptoms to diagnosis was 4.1 months. Chest X-ray revealed active pulmonary tuberculosis in 14 of 18 patients (78%), 4 of 14 patients were military type. The colonic tuberculosis involved in ileocecal area in 6, ileocecum and contiguous colonic regions in 7, segmental colonic involvement in 4, and pancolitis in 1 patient. Multiple ulceration and ulcerohypertrophic lesions were the major colonoscopic findings. Typical caseating granuloma were found in 5 cases (36%) from colonoscopic biopsy, the other 5 from surgical resected specimens. Antituberculous therapy produced remarkable symptomatic improvement in all patients except 2 cases complicated with intestinal obstruction necessitating laparotomy. Colonoscopy with biopsy is a useful diagnostic tool in early diagnosis and avoiding unnecessary laparotomy in colonic tuberculosis.
The prevalence and prognostic significance of bacterascites (BA) were prospectively studied in 443 predominantly HBsAg-positive cirrhotic patients with ascites. Spontaneous bacterial peritonitis (SBP), culture-negative neutrocytic ascites (CNNA), and BA were identified in 12.4%, 8.4%, and 10.8%, respectively. Of these, 67%, 70%, and 71%, respectively, had peritonitis-related signs or symptoms. Among patients with SBP or CNNA, the clinical and laboratory data showed no significant difference between the symptomatic and asymptomatic groups. In contrast, among the patients with BA, the symptomatic group had significantly higher levels of serum total bilirubin and prolonged prothrombin time and significantly lower levels of ascitic fluid total protein than the asymptomatic group. Furthermore, the clinical and laboratory data were relatively similar between patients with asymptomatic BA and those with sterile ascites. In contrast, patients with SBP, CNNA, or symptomatic BA exhibited significantly more severe degrees of liver disease and significantly lower levels of ascitic fluid total protein than those with sterile ascites. There was no statistically significant difference between SBP and bacterascites regarding flora. All patients with SBP, CNNA, or symptomatic BA received antibiotic treatment immediately after paracentesis, as did six of the 14 patients with asymptomatic BA for concurrent respiratory or urinary tract infection, while the remaining eight patients with asymptomatic BA were followed clinically without treatment. Repeated paracentesis in the latter revealed no evidence of SBP or CNNA. The in-hospital mortality for sterile ascites was 22.8%, significantly lower than the 54.5% for SBP, 43.2% for CNNA, and 50% for symptomatic BA, but similar to the 21.4% for asymptomatic BA.(ABSTRACT TRUNCATED AT 250 WORDS)
A 23-yr-old male with acute hepatitis A and coexistent hepatitis C became critically ill 3 wk after the onset of fever and jaundice with progressive anemia, thrombocytopenia, and hepatosplenomegaly. Bone marrow biopsy revealed hemophagocytosis. Despite aggressive supportive treatment with parenteral steroids, the patient died of disseminated intravascular coagulopathy with gastrointestinal bleeding. Necropsy of the liver showed histiocyte aggregation in the portal area with hemophagocytosis.
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Base-pair formation between two hairpin loops--a "kissing" complex--is an RNA-folding motif that links two elements of RNA secondary structure. It is also a unique protein recognition site involved in regulation of ColE1 plasmid DNA replication. The trans-activation response element (TAR), a hairpin and bulge at the 5' end of the untranslated leader region of the human immunodeficiency virus 1 mRNA, enhances the transcription of the virus and is necessary for viral replication. Gel electrophoresis and absorbance melting curves indicate that a synthesized RNA hairpin (Tar*-16) with a loop sequence complementary to the TAR loop sequence (CUGGGA) associates specifically with a 16-nucleotide TAR hairpin (Tar-16) to form a stable complex. RNase T1 probing indicates that the three guanines in the Tar-16 loop become inaccessible in the complex. NMR imino proton spectra reveal that 5 base pairs are formed between the two hairpin loops (Tar-16 and Tar*-16); only the adenine at the 3' terminus of the TAR loop does not form a base pair with the 5'-terminal uracil of the complementary loop. A 14-nucleotide hairpin [CCUA(UCCCAG)UAGG] with a loop sequence complementary to the TAR loop is conserved within the gag gene of human immunodeficiency virus 1. A synthesized RNA hairpin corresponding to this conserved sequence also binds to the Tar-16 hairpin with high affinity. It is possible that the same RNA loop-loop interaction occurs during the viral life cycle.
This study was conducted to clarify the effects of vibration on the peripheral nerves. Rat tails were exposed to vibration (acceleration 56.9 m/s2, frequency 60 Hz, amplitude 0.4 mm for two or four hours daily, six days a week. The maximum motor conduction velocity (MCV), the amplitude of evoked response, and the motor distal latency were measured on rat tail nerves every two months. Thin sections of tail nerves were examined under the electron microscope after 200, 500, and 800 hours of vibration. Neurophysiological and ultrastructural changes in tail nerves increased with the dose of vibration. In the groups exposed to vibration the MCVs were significantly reduced after a vibration time up to 400 hours, whereas the motor distal latency was not delayed significantly until 600 vibration hours. The ultrastructural changes were (1) detachment of the myelin sheath from the axolemma, (2) constriction of the axon, (3) protrusion of the myelin sheath into the axon, (4) accumulation of vacuoles in paranodal regions, and (5) dilatation of the Schmidt-Lanterman incisures. The ultrastructural changes induced by vibration in the paranodal regions and myelin sheaths were possibly responsible for the reduction in MCVs.
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Deacetylation of octa-O-acetylsucrose (1) with Alcalase or protease N gave the 2,3,4,6,3',4',6'-hepta-acetate (2) as the initial major product with the 2,3,4,6,3',4'-hexa-acetate (3) as the subsequent main product. The 2,3,4,1',3',4',6'-hepta-acetate (5) was obtained from 1 by the action of lipase OF or lipase AP6, and the 2,3,4,6,1',3',6'-(4) and 2,3,4,6,1',3',4'-hepta-acetate (7) by the action of Candida lipase and chymotrypsin, respectively. The 2,3,6,1',3',4',6'-hepta-acetate (6) was formed from 5 by acyl migration.
A case of fetus-in- fetu is reported. It occurred in an 8-week-old Korean boy who had been born by cesarean section due to abdominal distension. The fetus-in- fetu was connected to the superior mesenteric artery and consisted of two masses, apparently representing two portions of an acardiac monster. There was an amniotic membrane covering both masses, and the umbilical cord clearly was identifiable. One mass included the brain, eye, trachea, salivary glands, thyroid, pancreas, spleen, etc., while the other mass contained extremity bones, vertebrae, testis, adrenals, and intestinal loops. This is probably a case of separated fetus-in- fetu that showed unusually well-developed internal organs.