Biomedical subjects
Publications and source records attributed to L H Lee.
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HT29 cells endogenously express the cystic fibrosis transmembrane conductance regulator (CFTR) and have been used previously as a model to examine cellular regulation of CFTR expression and chloride secretory function. Homologous recombination has been used to specifically disrupt CFTR transcription in the HT29-18-C1 subclone. Experiments demonstrate successful disruption of a CFTR allele by DNA constructs, which target insertion of the neomycin phosphotransferase gene into CFTR exon 1 via homologous recombination. The mutation of one allele is a partial knockout because this cell line has multiple CFTR alleles. The mutation is confirmed by polymerase chain reaction (PCR) and genomic Southern blot analysis. A 52-68% reduction in CFTR mRNA levels is observed in the mutant cell line by both Northern and PCR analysis. However, Western blots show no decrease in total CFTR protein levels. Consistent with the lack of reduction in CFTR protein, the partial knockout mutant does not demonstrate alterations in cyclic AMP or calcium stimulation of chloride efflux or net osmolyte loss. Results suggest that posttranscriptional regulation of CFTR levels may contribute to maintenance of cellular chloride transport function.
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The sequence of RNA genome segment S4 of the avian reovirus (ARV) strain S1133 was determined. S4 RNA is 1185 base pairs long and contains one open reading frame encoding a protein of 367 amino acid residues (40.6 kDa), the similar size as the known S4 gene product (sigma NS), with a net charge of -1 at neutral pH. The S4 RNA sequence possesses a pentanucleotide sequence UCAUC at the 3'-terminus of its plus strand like in ARV S1 and S3 segments and ten segments of mammalian reovirus (MRV). The predicted amino acid sequence comparison revealed that the homology is 44.02%, 45.71%, and 42.33% for ARV sigma NS and three serotypes of MRV sigma NS, respectively. The relatively high content of alpha-helix structure in the C-terminal portion of ARV sigma NS suggests that this protein may functionally relate to MRV sigma NS. Northern blot hybridization showed that a 32P-labeled cDNA insert S4-49 from ARV S4 RNA cross-hybridized with the corresponding RNA segments of all seven strains of ARV tested.
The double-stranded RNA genome segment S3 of avian reovirus (ARV) S1133 was cloned following polyadenylation of both strands and cDNA synthesis of S3 RNA. The complete segment S3 nucleotide sequence was determined. S3 is 1196 base pairs long with one long open reading frame (ORF). The ORF possesses the AUG initiation codon in an optimum context for translation and starts at the first initiation codon (residue 24) and extends for 367 codons, sufficient to encode a protein of the same size as the known S3 gene product, protein sigmaB, one of the major outer capsid proteins of avian reovirus (Mr 41471). Protein sigmaB was subsequently expressed in Escherichia coli. The expressed protein sigmaB was indistinguishable from virion protein sigmaB as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, immunoblot assay, and N-terminal amino acid sequencing of several peptides generated by Staphyloccus aureus V8 protease digestion. ARV S3 genome segment possesses a pentanucleotide UCAUC at the 3'-terminus of its plus strand. The pentanucleotide sequence is common to the other genome segment S1 of ARV and to ten genome segments of mammalian reovirus at the 3'-terminus of their plus strands. Amino acid sequence analysis revealed that ARV sigmaB does not contain a repeated basic amino acid motif as do the three serotypes of mammalian reovirus. The results of amino acid sequencing suggest that the most susceptible cleavage sites of sigmaB to V8 protease are located in a hydrophilic area between amino acids 95 and 140.
OBJECTIVE: To establish the frequency, symptoms, duration, and treatment methods of childhood migraine in an urban area. DESIGN: Self-administered questionnaire survey. The questionnaire was designed according to criteria suggested by the International Headache Society (IHS). PARTICIPANTS: In 1994, with the help of school officials in 41 elementary and middle schools in the Greater Cleve-land Area, 18,000 questionnaires were distributed to the parents of schoolchildren who ranged in age from 5 to 13 years. RESULTS: Of the total 2572 respondents, 222 children (8.6%) met the IHS criteria for migraine. Male to female ratio was 1:1.2 (99:120), 65.8% had a positive family history of migraine, 30.6% had onset of migraine at 4 to 5 years of age, and 54.1% reported having an aura (71% of these were visual aura). The headaches were mostly pulsating, poorly localized, lasted about 2 to 12 hours, and were aggravated by motion, noise, and bright light. The associated symptoms were nausea, vomiting, photophobia, and phonophobia. During the attack, 43% of the migraineurs had to stay in bed, and 27% were unable to attend school. Only 19.8% of the migraineurs were diagnosed to have migraine by their physicians, and most of these had not received treatment. CONCLUSION: This study in an urban area indicates that childhood migraine is a common, often underdiagnosed disorder that causes significant suffering for children and their families.
Conscientious sign-out between medical interns is important for the continuity of care of hospitalized patients. We developed a standardized sign-out card that prompted the intern going off duty to transmit patient care information to the inter on call. The card was tested in a prospective, randomized, controlled trial in which one group of interns used the card, and another group did not. Any instance of poor sign-out was reported on a questionnaire completed by the intern who had been on call the previous night. The group using the sign-out cards reported poor sign-out on 8 nights (5.8% of questionnaires), and the control group reported it on 17 nights (14.9% of questionnaires, p = .016). The card was time-effective and inexpensive, resulted in more complete data recording, and possibly decreased the morbidity associated with poor sign-out.
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The purposes of this research study were: (1) to determine whether changes in cardiac rate, skin temperature, and/or electrodermal activity occur as children change mental imagery and (2) to determine whether such changes are related to age, sex, or other variables. Children who were evaluated in this study had no previous experience with hypnosis or biofeedback training and were in good health with no learning disabilities. Thirty-eight boys and 38 girls ranging in age from 5 to 15 years were studied in a comfortable setting with a constant room temperature and biofeedback equipment. A Procomp 5DX computer software unit was used to measure autonomic reactivity during baseline and mental processing periods. After baseline monitoring indicated stabilization of autonomic measures, each child was asked to think about being in a quiet, pleasant place for 120 seconds. Pulse rate, skin temperature, and electrodermal activity were recorded. A resting period followed, and each child was then asked to think about an exciting activity, such as a preferred sports activity, for another 120 seconds. At the end of this monitoring, each child was asked to describe what had been his/her mental imagery during the two monitoring periods. Data analysis used paired t tests and repeated measures analysis of variance. For all children, the pulse rates showed significant decreases (p < .001) during quiet and relaxing imagery and significant increases (p < .001) during active imagery. Skin temperatures increased significantly (p < .001) during quiet imagery and active imagery, whereas electrodermal activity decreased (p < .001) during active imagery. Observed changes did not relate to age or sex. The results confirm our clinical observations that deliberate changing of mental imagery by children results in immediate autonomic changes. Questions evolving from this study and similar studies done in adults are: (1) Do average-thinking processes impact on autonomic changes over long periods of time and (2) do these changes ultimately impact on health, such as cardiovascular status?
All retroviruses need mechanisms for nucleocytoplasmic export of their unspliced RNA and for maintenance of this RNA in the cytoplasm, where it is either translated to produce Gag and Pol proteins or packaged into viral particles. The complex retroviruses encode Rev or Rex regulatory proteins, which interact with cis-acting viral sequences to promote cytoplasmic expression of incompletely spliced viral RNAs. Since the simple retroviruses do not encode regulatory proteins, we proposed that they might contain cis-acting sequences that could interact with cellular Rev-like proteins. To test this possibility, we initially looked for a cis-acting sequence in avian retroviruses that could substitute for Rev and the Rev response element in human immunodeficiency virus type 1 expression constructs. A cis-acting element in the 3' untranslated region of Rous sarcoma virus (RSV) RNA was found to promote Rev-independent expression of human immunodeficiency virus type 1 Gag proteins. This element was mapped between RSV nucleotides 8770 and 8925 and includes one copy of the direct repeat (DR) sequences flanking the RSV src gene; similar activity was observed for the upstream DR. To address the function of this element in RSV, both copies of the DR sequence were deleted. Subsequently, each DR sequence was inserted separately back into this deleted construct. While the viral construct lacking both DR sequences failed to replicate, constructs containing either the upstream or downstream DR replicated well. In the absence of both DRs, Gag protein levels were severely diminished and cytoplasmic levels of unspliced viral RNA were significantly reduced; replacement of either DR sequence led to normal levels of Gag protein and cytoplasmic unspliced RNA.
We describe nine asymptomatic chronic carriers of hepatitis B virus, four males and five females, with a mean age of forty-six years and all were Chinese, who developed exacerbation of hepatitis following chemotherapy for haematological malignancies. Seven patients had non-Hodgkin's lymphoma of whom three were treated with MACOP-B, two with BCEPP, one with PROMACE-CYTABOM and one with CHOP. Two patients had acute myeloid leukaemia and were treated with daunorubicin and cytosine arabinoside. Exacerbation of hepatitis occurred between one to four weeks following the last course of chemotherapy in eight patients. Two patients developed exacerbation of hepatitis when the dosage of prednisolone was reduced after they had ten weeks of high dose prednisolone. The outcome was fatal in six patients; all of whom developed hepatic encephalopathy. In four of these patients, alanine transaminase levels exceeded 1000 iu/l. Cytotoxic and immunosuppressive therapy permit enhanced viral replication. Withdrawal of the drugs results in partial restoration of immunocompetence and leads to rapid destruction of hepatocytes with consequent hepatic necrosis. Hence, patients who are hepatitis B virus carriers undergoing chemotherapy should be closely monitored. The fatal outcome of reactivation of chronic hepatitis B virus warrants prospective trials addressing preventive measures.
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The acronym HELLP describes a syndrome of (H) hemolysis, (EL) elevated liver enzymes, and (LP) low platelets, which symptomatically defines a unique group of preeclamptic/eclamptic women. Pregnancies complicated by this syndrome are associated with poor maternal and fetal outcome. This poses a considerable challenge to the anesthesiologists as many of these patients require emergent Cesarean section. We reported a 30-year-old woman with gestation of 32 wk who sustained Cesarean section under the impression of pregnancy with HELLP syndrome. General anesthesia was performed for this patient. The preoperative evaluation, general management, and intraoperative monitoring system were described. The individual role and use of labetalol and propofol were also discussed in this report.
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Platelet phospholipid dependent thrombin generation was determined in 20 patients with thrombocytosis, 18 with thrombocytopenia, and 25 normal controls, using a quantitative chromogenic assay. Platelets from patients with myeloproliferative disorders displayed normal lag times to 20 nM thrombin concentration but increased thrombin potentials, even when corrected for platelet size. Platelets from patients with reactive thrombocytosis supported normal thrombin generation. ITP platelets were large, with a proportionate increase in thrombin potentials, but very short lag times to 20 nM thrombin concentration. Following marrow ablation there was a progressive loss of activation-induced enhancement of thrombin generation. Platelets from patients with idiopathic aplastic anaemia supported normal thrombin generation. These findings indicate that platelet phospholipid-dependent thrombin generation is altered in many patients with a variety of quantitative platelet disorders, and this may be an important determinant of the clinical expression of these disorders.