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Biomedical subjects

D H Lee

Publications and source records attributed to D H Lee.

At least 19 recordsLinked to original sources
PubMed1992

Repression of the araBAD promoter from araO1.

DNA looping between the araO2 and araI sites holds the uninduced or basal level of expression of the araBAD genes from the pBAD promoter at a low level. Despite the presence of another and closer site potentially capable of mediating looping to araI, no repression from this site, called araO1, is observed. Here we show, using both in vivo and in vitro experiments, that the araO1 site is not normally occupied by AraC protein under repressing conditions, but that if AraC protein is overproduced and the araO2 site is absent, araO1 is then occupied and repression of pBAD can be observed.

AraC Transcription Factor↗
PubMed1992

PRS3 encoding an essential subunit of yeast proteasomes homologous to mammalian proteasome subunit C5.

We found by computer analysis that a putative yeast proteasome subunit gene named PRS3 that encodes a protein very similar to subunit C5 of rat and human proteasomes is located immediately 3' to the ERD2 gene of Saccharomyces cerevisiae. The similarity of the primary structures of the two suggests that this subunit may have a common function in proteasomes of all eukaryotes. The protein, deduced from the open reading frame of PRS3, consists of 242 amino acid residues with a calculated molecular weight of 27,077. Chromosomal disruption of the PRS3 gene created a recessive lethal mutation. Physical mapping by hybridization to intact S. cerevisiae chromosomal DNA showed that the PRS3 gene is located on chromosome II, unlike two other subunit genes, PRS1 and PRS2, which are located on chromosomes XV and VII, respectively. These findings indicate that the PRS3 protein is a subunit of yeast proteasomes that is essential for cell viability.

Amino Acid Sequence↗
PubMed1992

Serial cranial and spinal cord magnetic resonance imaging in multiple sclerosis.

Twenty-nine mildly disabled patients with multiple sclerosis underwent serial clinical and magnetic resonance imaging (MRI) evaluations (pre- and postgadolinium cranial and spinal cord MRI) on at least 3 occasions at 13-week intervals and during periods of suspected relapse. Using clinical judgment of the presence of recent active disease as the gold standard, combined MRI studies confirmed the clinical impression of active disease in 93% of follow-up visits (sensitivity) and the absence of active MS in 63% of follow-up visits (specificity). None of the cranial and spinal MRI-detected abnormalities disappeared. Gadolinium administration particularly increased the yield of spinal MRI. Cranial MRI alone detected 80% of the MRI-active visits. Clinical and MRI concordance was significantly better for the presence of recent disease activity than for the anatomical localization of the presumed site of activity. MRI evidence of apparent ongoing disease activity was seen more frequently in patients believed to have active multiple sclerosis in the preceding year (13 of 21) than in patients who had been in clinical remission for at least the 2 preceding years (2 of 8). Although clinical evidence of new disease activity was much less common in patients with active, chronic-progressive disease (1 of 8) than in patients with active, relapsing disease (9 of 13), the proportion of patients with either infrequent relapses, frequent relapses, or slow chronic-progressive disease in the preceding year in whom MRI activity developed and the pattern of this new MRI activity was similar between these types of active patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain↗
PubMed1992

Frequency and distribution of phenylketonuric mutations in Orientals.

The frequency and distribution of eight mutations (R111X, IVS4nt-1, Y204C, R243Q, IVS7nt-2, W326X, Y356X, and R413P) in the phenylalanine hydroxylase gene of Orientals in Japan and Korea were examined by allele-specific oligonucleotide hybridization. The mutant alleles comprised 54 and 55% of the phenylketonuria (PKU) chromosomes examined in 36 patients in Japan and 10 patients in Korea, respectively. The spectrum of PKU mutations in Japan was similar to that in China, particularly in northern China, but different from that in Korea. The IVS4nt-1 mutation had a high frequency in Korea and southern China, due to the result of the founder effect and genetic drift. The R413P mutation, which may have originated in the regions surrounding the Baikal, expanded to northern China and Japan. We did not find Caucasian mutations in the Japanese or Korean PKU chromosomes. Thus, PKU mutations occurred after racial divergence between Caucasians and Mongoloids, and there were different founding populations for PKU in the two populations.

Alleles↗
PubMed1992

Calcified gastric carcinoma: CT findings.

The computed tomographic (CT) findings of 13 cases of calcified gastric carcinoma were analyzed retrospectively. Eleven cases were confirmed as a mucinous adenocarcinoma by surgery (three cases), or endoscopic biopsy (eight cases). Two cases were diagnosed as adenocarcinoma by endoscopic biopsy. In all cases the calcifications were of the punctate or miliary shape and the size varied from 1-3 mm in diameter. The calcifications were located in the thickened gastric wall in all cases, and were seen in metastatic lesions such as lymph nodes and the liver in two cases. In 10 cases, some tumor portions showed lower attenuation number than that of the muscle on CT scans, and corresponded to mucin pool in tumor portions histologically. Twelve cases were in inoperable advanced stage.

Adenocarcinoma, Mucinous↗
PubMed1992

Methylparaben and propylparaben do not alter cerebral blood flow in humans.

In vitro studies suggest that the preservatives methylparaben and propylparaben included in some multidose vials of succinylcholine are the cerebral vasodilators responsible for the increases in intracranial pressure (ICP) documented after succinylcholine administration. To test this hypothesis, we measured cerebral blood flow (CBF) and cerebral blood flow velocity (CBFV) with inhaled 133Xenon and transcranial Doppler respectively in healthy humans before and after the intravenous administration of methylparaben and propylparaben. We found no change in either CBF or CBFV after the paraben injections and therefore conclude that it is unlikely that the rise in ICP seen with succinylcholine is caused by cerebral arterial vasodilatation from the preservatives methylparaben and propylparaben.

Cerebrovascular Circulation↗
PubMed1992

The medical treatment of a tuberculous tracheo-oesophageal fistula.

Tracheo-oesophageal (TE) fistulas caused by Mycobacterium tuberculosis are rare and usually require both surgical treatment and medical treatment with antituberculosis drugs. A patient with a tuberculous TE fistula and mediastinal lymphadenitis was successfully treated by medical management alone.

Adult↗
PubMed1992

Endoscopic carpal tunnel release: a cadaveric study.

Five surgeons performed endoscopic (Dyonics) carpal tunnel releases on 24 fresh cadaver wrists. In 50% of the specimens, transection of the transverse carpal ligament was incomplete. The average amount of incomplete release was 31% (range, 0% to 53%). Three types of incomplete release were noted: (1) release of Guyon's canal release--one, (2) incomplete distal ligament release--five, and (3) incomplete central or superficial release--six. Other technical errors were noted in nine of 24 specimens. There were no nerve lacerations. Endoscopic carpal tunnel release is either a technically demanding procedure, commonly results in incompletely released ligaments, or both. Proper training, followed by practice on several cadaver specimens before its clinical use, is recommended.

Anthropometry↗
PubMed1992

Mediastinal pancreatic pseudocyst with recurrent pleural effusion. Demonstration by endoscopic retrograde cholangiopancreatogram and subsequent computed tomography scan.

Mediastinal pseudocysts of internal pancreatic fistulas are rare as a cause of bilateral pleural effusions even in relapsing pancreatitis. We describe a 38-year-old man with recurrent bilateral pleural effusion as a complication of a pancreatic pseudocyst. Extension of a pancreatic pseudocyst into the posterior mediastinum was clearly identified by endoscopic retrograde cholangiopancreatogram and subsequent computed tomography scan of the abdomen and chest, and the complication was successfully treated by surgical management. We stress the importance of definite assessment of the communication of pancreatic pseudocyst with mediastinum in patients with pancreatitis who develop recurrent pleural effusions.

Adult↗
PubMed1992

Endobronchial tuberculosis. Clinical and bronchoscopic features in 121 cases.

The clinical and bronchoscopic features of endobronchial tuberculosis in 121 patients were retrospectively investigated. The peak incidence occurred in the second decades, with 3.8 times higher incidence noted in female than in male subjects. A barking cough with sputum was the most common chief complaint in 61.1 percent. Parenchymal infiltration and/or consolidation was the most common roentgenographic finding of the chest in 58.6 percent. Hypertrophy with luminal narrowing was the most common bronchoscopic finding in 43 percent. Bronchoscopically, right upper and right main bronchus were the most frequently involved in 30.5 percent. It was concluded from these data that using fiberoptic bronchoscopy allows not only substantial meaningful assessment of endobronchial tuberculosis but also relieves atelectasis eventually resulting in successful treatment with antituberculosis drugs.

Bronchi↗
PubMed1992

Mass treatment of head louse infestation with Sumithrin powder in primary schools in Korea.

A mass treatment of head louse infestation with Sumithrin powder (0.4% phenothrin) in primary school children was implemented during the period of September 1991-May 1992. The infestation rate of total 2,515 children was 38.6% in average (21.2% in boys and 57.2% in girls). The reduction rate of head louse infestation was 93.4% with a single treatment and 94.8% with double consecutive treatments with about 10 days interval, which indicated that a single treatment would be recommended for the mass treatment in the community. Long term follow-up after Sumithrin powder application for head louse control in a primary school showed that the infestation rate dropped from 33.1% before treatment to 5.4% by seven months after treatment, giving a 83.4% reduction rate.

Age Factors↗
PubMed1992

Sonographic detection of duodenal ulcer.

Using a wall thickness of greater than 5 mm for the first portion of the duodenum as the criterion for the sonographic diagnosis of duodenal ulcer, we studied the value of sonography in detecting this lesion. Endoscopy (88 patients) and upper gastrointestinal barium studies (12 patients) were used as the gold standards for the diagnosis. The study included 100 patients in whom gastrointestinal disease was suspected (20 with duodenal ulcer and 80 with normal findings). Of the 20 duodenal ulcers verified by endoscopy or upper gastrointestinal series, 13 patients had duodenal wall thickening, six had normal wall thickness, and one was nondiagnostic. Of the 80 subjects with normal findings on endoscopy or upper gastrointestinal series, 73 patients had a normal duodenum, four had wall thickening, and three were nondiagnostic. Considering the four nondiagnostic cases as sonographic errors, there were six false-negative cases and four false-positive cases (a sensitivity of 65%, specificity of 91%, positive predictive value of 76%, and negative predictive value of 92%). Our results show that sonography is not sufficiently sensitive to be used as a screening test, nor is it specific for duodenal ulcer, but a thickened duodenal wall of over 5 mm on sonography warrants additional work-up.

Duodenal Ulcer↗
PubMed1992

UV absorption complicates PCR decontamination.

UV irradiation is widely used to inactivate contaminating DNA in PCR. Highly UV-absorbent deoxyribonucleoside triphosphates in PCR mixtures reduce the efficiency of UV decontamination. Optimal decontamination may be achieved by irradiating the PCR mixture without the deoxyribonucleoside triphosphates.

Artifacts↗
PubMed1992

Staging and treatment of primary and persistent (recurrent) osteoid osteoma. Evaluation of intraoperative nuclear scanning, tetracycline fluorescence, and tomography.

The purposes of this study were (1) to evaluate the various methods of preoperative staging of osteoid osteomas, (2) to compare the different methods of intraoperative localization and excision of the tumor, and (3) to develop a clinical strategy for the treatment of persistent (recurrent) lesions. From 1978 until 1986, 14 consecutive patients had excision of osteoid osteomas. All patients' operative reports, roentgenograms, bone scans, computed tomographic scans and histologic studies were reviewed. With an average follow-up period of 94.5 months, 13 of 14 patients were cured with one operative procedure. One patient required two procedures. No patient developed a recurrence. Eleven of 14 niduses were confirmed on hematoxylin and eosin sections. Computed tomographic scan was the most useful preoperative study in localizing the nidus. It helped determine the surgical approach and the portion of bone to be resected. Intraoperative nuclear scanning (IONS) is a reliable technique in confirming complete removal of the nidus, with no increase in operative time. Intraoperative scanning did not appreciably affect the amount of bone resected. Recurrent tumors can be reliably resected, with a high cure rate, by careful preoperative staging and with use of IONS.

Adolescent↗
PubMed1991

Genomic structure of the human prototype strain H of hepatitis C virus: comparison with American and Japanese isolates.

Genomic RNA from the human prototype strain H of the hepatitis C virus (HCV-H) has been molecularly cloned and sequenced. The HCV-H sequence reported consists of 9416 nucleotides including the 5' and 3' untranslated regions. HCV-H shows 96% amino acid identity with the American isolate HCV-1 but only 84.9% with the Japanese isolates HCV-J and HCV-BK. In addition to the hypervariable region (region V) previously identified in the putative E2 domain, three other variable domains were identified: region V1 (putative E1), region V2 (putative E2), and region V3 (putative NS5). These regions appear rather conserved (86-100%) among the American isolates (HCV-1 and HC-J1) or among various Japanese isolates (HCV-J, HCV-BK, HCV-JH, and HC-J4) but show striking heterogeneity when the two subgroups are compared (42-87.5% amino acid difference). A structural similarity between the 5'-terminal hairpin structure of HCV and of poliovirus was observed. This study further suggests the existence of at least two genomic subtypes of HCV and confirms a distant relationship between HCV and pestiviruses.

Amino Acid Sequence↗
PubMed1991

Molecular cloning and sequence analysis of cDNAs for five major subunits of human proteasomes (multi-catalytic proteinase complexes).

Proteasomes are multicatalytic proteinase complexes consisting of a set of non-identical polypeptide components. Of these multiple components, the nucleotide sequences of five major subunits (named HC2, HC3, HC5, HC8 and HC9) of human proteasomes have been determined from recombinant cDNA clones by screening a human HepG2 hepatoblastoma cell cDNA library with rat proteasome cDNAs isolated previously as probes. The polypeptides deduced from their nucleotide sequences consisted of 263, 234, 241, 255 and 261 amino acid residues with calculated molecular weights of 29,554, 25,897, 26,487, 28,431 and 29,482, respectively, which are encoded by single independent genes. The primary structures of these subunits of human proteasomes closely resemble those of their rat counterparts and show considerably high inter-subunit homology, although the homology of HC5 is relatively low. These findings, together with the structural similarities of other eukaryotic proteasomes including those of Drosophila and yeast (Saccharomyces cerevisiae) support and extend the previously proposed concept that eukaryotic proteasome genes form a multi-gene family with the same evolutionary origin.

Amino Acid Sequence↗