Cot death in Hong Kong: an unexplained rarity.
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Hong Kong↗
Biomedical subjects
N Lee
Publications and source records attributed to N Lee.
Oligomerization of pregnancy-specific beta 1-glycoprotein (SP1) at physiologic pH and ionic strength.
Highly purified pregnancy-specific beta 1-glycoprotein (SP1) migrated in gel electrophoresis as a homogeneous species and behaved as a single species in 6 mol/l guanidinium chloride (GdmCl), both in the ultracentrifuge and HPLC. At physiologic pH and ionic strength, in the absence of GdmCl, SP1 existed in the form of oligomers of apparent molecular weights of 40 000 to greater than 300 000. The specific activity of these oligomers varied over a 5-fold range. Electrophoretic mobility also varied among SP1 oligomers, with increasing (alpha-like) mobility shown by oligomers of increasing molecular size. Oligomerization may explain some or all of the reports of SP1 heterogeneity.
Chromatography, High Pressure Liquid↗
Evaluation of a seven day course of oxytetracycline in women with chlamydial cervicitis.
In an urban clinic for sexually-transmitted diseases, 270 women with cervical swabs culture positive for Chlamydia trachomatis were treated with 250 mg oxytetracycline orally four times daily for 7 days. Chlamydial infection was found again in 17 of 220 (7.3%) women examined one month after treatment, and in 12 of 113 (9.7%) women reexamined three months after treatment. Even in cases where reinfection seemed unlikely, only 177 of 198 (89%) were cured. Most post-treatment infections were not clinically apparent, and laboratory follow-up was essential for evaluation of chemotherapy.
Chlamydia Infections↗
The organization of the araBAD operon of Escherichia coli.
The nucleotide (nt) sequence of the araBAD operon of Escherichia coli B/r has been determined. The nt sequence predicts a transcript of about 4250 nt. The coding regions of araB, araA and araD genes were identified by partial amino acid (aa) sequences of the purified proteins and their cleavage products. We have deduced that the polypeptides encoded by the araBAD operon consist of 566 (araB), 500 (araA) and 231 (araD) aa residues. The operon contains a leader sequence of 27 nt. The intergenic region between araB and araA is 10 bp in length, while the araA and araD genes are separated by 283 bp consisting primarily of six REP sequences. Comparison of the E. coli sequence with that of Salmonella typhimurium [Lin et al., Gene 34 (1985) 111-122; 123-128; 129-134] shows that, while considerable divergence in nt sequence has occurred, the aa sequences are largely conserved. The most pronounced difference, found in the araD gene, is the deletion of a single nt in the S. typhimurium sequence.
Amino Acid Sequence↗
Human liver apolipoprotein B-100 cDNA: complete nucleic acid and derived amino acid sequence.
Human apolipoprotein B-100 (apoB-100), the ligand on low density lipoproteins that interacts with the low density lipoprotein receptor and initiates receptor-mediated endocytosis and low density lipoprotein catabolism, has been cloned, and the complete nucleic acid and derived amino acid sequences have been determined. ApoB-100 cDNAs were isolated from normal human liver cDNA libraries utilizing immunoscreening as well as filter hybridization with radiolabeled apoB-100 oligodeoxynucleotides. The apoB-100 mRNA is 14.1 kilobases long encoding a mature apoB-100 protein of 4536 amino acids with a calculated amino acid molecular weight of 512,723. ApoB-100 contains 20 potential glycosylation sites, and 12 of a total of 25 cysteine residues are located in the amino-terminal region of the apolipoprotein providing a potential globular structure of the amino terminus of the protein. ApoB-100 contains relatively few regions of amphipathic helices, but compared to other human apolipoproteins it is enriched in beta-structure. The delineation of the entire human apoB-100 sequence will now permit a detailed analysis of the conformation of the protein, the low density lipoprotein receptor binding domain(s), and the structural relationship between apoB-100 and apoB-48 and will provide the basis for the study of genetic defects in apoB-100 in patients with dyslipoproteinemias.
Amino Acid Sequence↗
Glanzmann's thrombasthenia: diagnosis supplemented by HP1-1D monoclonal antibody.
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Adolescent↗
Human ApoB-100 gene resides in the p23----pter region of chromosome 2.
Human apolipoprotein (apo) B-100 is the major apolipoprotein of low density lipoproteins (LDL) and the principal ligand for interaction with the LDL receptor. The gene for apoB-100 has been localized to the p23----pter region of chromosome 2 by filter hybridization analysis with radiolabelled apoB-100 cDNA probes and human-mouse somatic cell hybrids containing chromosome 2 translocations. Other genes at the end of the short arm of chromosome 2 include acid phosphatase, proopiomelanocortin complex, malate dehydrogenase, and N-myc, the latter gene has been previously localized to the same bands (2p23----pter) as the apoB-100 gene. The localization of the apoB-100 gene to the p23----pter region of chromosome 2 completes the genomic organizational relationship of the LDL receptor and the two apolipoprotein ligands for the LDL receptor, apoE and apoB-100; the LDL receptor and apoE having been previously localized to chromosome 19.
Animals↗
An analysis of some risk factors for lung cancer in Hong Kong.
Lung cancer has been the major cause of cancer death in Hong Kong for more than a decade. Although it is known that some 95% of male cases can be attributed to smoking, the etiological factors in women remain elusive. Among "never-smoked" female cases, increases in attributable risk from passive smoking were limited to only some of the histological types of lung carcinomas, and an overall analysis of all types did not reveal any significant increase in relative risk from this source. Other environmental factors which encourage bronchial irritation are suspected. Methodological differences may explain the differences in proportional distributions of histological lung tumor types noted between previous reports, and the risk values attributed therein to active and passive smoking.
Adolescent↗
Effects of Quantum Flux Density on Photosynthesis and Chloroplast Ultrastructure in Tissue-Cultured Plantlets and Seedlings of Liquidambar styraciflua L. towards Improved Acclimatization and Field Survival.
Liquidambar styraciflua L. seedlings and tissue-cultured plantlets were grown under high, medium, or low (315, 155, or 50 microeinsteins per square meter per second photosynthetically active radiation) quantum flux densities. Net photosynthesis, chlorophyll content, and chloroplast ultrastructure of leaves differentiated from these conditions were investigated. Seedling photosynthetic rates at light saturation were positively related to light pretreatments, being 6.44, 4.73, and 2.75 milligrams CO(2) per square decimeter per hour for high, medium, and low light, respectively. Cultured plantlets under all light conditions had appreciably higher photosynthetic rates than noncultured seedlings; corresponding rates were 12.14, 13.55, and 11.36 milligrams CO(2) per square decimeter per hour. Chlorophyll in seedlings and plantlets was significantly higher in low light-treated plants. Seedling leaves had chloroplasts with abundant starch regardless of light pretreatment. In high light, starch granules were predominant and associated with disrupted granal structure. Low light seedling chloroplasts had smaller starch grains and well-formed grana. In contrast, tissue culture-differentiated leaves were devoid of starch; grana were well organized in higher quantum flux density treatments, but disorganized at low flux densities.
Journal Article↗
Stimulation of human leukocytes by protein II+ gonococci is mediated by lectin-like gonococcal components.
We investigated the ability of carbohydrates, glycosidases, and concanavalin A to inhibit the stimulation of the human leukocyte oxidative burst by gonococci in the absence of serum. The gonococci used in this study contained protein II (P.II) outer membrane proteins, and neutrophil oxidative burst was measured by luminol-enhanced chemiluminescence (CL). The following carbohydrates inhibited CL induced by nonpiliated P.II+ gonococci: beta-D-glucosamine greater than N-acetylneuraminic acid (sialic acid) greater than mannose greater than alpha-methylmannoside greater than N-acetyl-beta-D-glucosamine greater than or equal to glucose greater than or equal to lactose. Fucose, galactose, or beta-D-galactosamine (all 100 mM) did not inhibit or slightly increased CL, indicating a specificity for the observed effects. Mannose and alpha-methylmannoside also inhibited induction of monocyte CL by P.II+ gonococci. Incubation of neutrophils with concanavalin A inhibited subsequent gonococcus-induced CL but not phorbol myristate acetate-induced CL. Treatment of neutrophils with alpha-mannosidase reduced subsequent gonococcus-induced CL greater than 99%, whereas such treatment of gonococci had no effect on their ability to induce neutrophil CL. Incubation of a P.IIb-containing variant of Neisseria gonorrhoeae FA1090 with anti-P.IIb monoclonal antibody inhibited subsequent stimulation of neutrophil CL in a dose-responsive manner, indicating a specific role for P.IIb in the stimulatory process. The data suggest that one or more lectin-like components on the surface of P.II+ gonococci mediate their ability to stimulate the oxidative burst of human phagocytes.
Antibodies, Monoclonal↗
Pseudomonas pseudomallei infection from drowning: the first reported case in Taiwan.
We report a case of Pseudomonas pseudomallei infection, in which the patient acquired the bacteria by aspiration of river water after a drowning incident near Manila, the Philippines. The pulmonary form of melioidosis was noted at the onset, but septicemia developed at a later stage. Positive blood cultures were obtained 17 days after the accident. The patient was treated successfully with a combination of amikacin and cephalothin. This is the first report of P. pseudomallei infection documented in Taiwan.
Amikacin↗
Chlamydial infections of the urethra in women.
Cervical and endourethral swabs from 360 untreated women attending a sexually transmitted disease (STD) clinic were cultured for Chlamydia trachomatis and other genitourinary pathogens. The patients included contacts of men with non-gonococcal urethritis, women with gonorrhoea, and those in whom symptoms suggestive of urinary tract infection were the main reasons for their attendance. Chlamydial infection of the urethra was less common than, and seldom occurred in the absence of, cervical chlamydial infection; it was frequently silent, producing no signs or symptoms of urethritis. Only 33/96 women with evidence of urethritis gave chlamydia positive urethral swabs, and 14 of them had other concurrent infections of the genitourinary tract. Chlamydia trachomatis thus does not appear to be a major cause of the signs and symptoms of urethritis commonly found in women attending STD clinics, and there seems to be no indication for taking routine urethral swabs to aid in the diagnosis of chlamydial infection in women.
Cervix Uteri↗
[A simple method for performing yeast carbohydrate assimilation test].
A modified auxanographic method was employed to perform carbohydrates assimilation test for 25 strains of yeasts representing the following 8 species: Candida albicans, C. glabrata, C. krusei, C. parapsilosis, C. stellatoides, C. tropicalis, Cryptococcus neoformans, and Rhodotorula glutinis. The results obtained were analyzed by comparing with the conventional auxanographic method, and it was found that the modified method was more accurate, rapid and easy in reading. The modified method was obviously easier in manipulation and more economic than that of Wickerham's broth technique and yeast assimilation agar slant technique.
Candida albicans↗
Cloning with tandem gene systems for high level gene expression.
A method has been devised for increasing the copy number of a gene (or genes) cloned into a plasmid while minimizing the size of the plasmid. If n copies of a transcriptional unit are cloned, including the promoter, coding region and terminator, the size of the plasmid will increase by n times the total size of the unit. However, if we borrow the concept of polycistronic operon and sandwich n structural genes, each with its own ribosome binding-site, between a promoter and a transcription terminator, there will be a space saving equivalent to n-1 promoters and n-1 transcription terminators. We have constructed plasmids in which an E. coli lipoprotein promoter is followed by 1 to 4 human leukocyte interferon genes and a transcription terminator. The applications of this method in genetic engineering are discussed.
Amino Acid Sequence↗
Mechanisms of deoxyadenosine toxicity in human lymphoid cells in vitro: relevance to the therapeutic use of inhibitors of adenosine deaminase.
Deoxyadenosine (AdR) appears to be central to the molecular events mediating immunodeficiency in children born with adenosine deaminase (ADA) deficiency but it is still uncertain whether lymphotoxicity is due to AdR directly inhibiting transmethylation reactions in which S-adenosylmethionine is the methyl group donor, or is due to phosphorylation of AdR to deoxyadenosine triphosphate (dATP) which then inhibits ribonucleotide reductase or is due to other mechanisms. Using AdR and the ADA inhibitor deoxycoformycin (dCF) and assessing cell viability, nucleoside incorporation into RNA and DNA, as well as measuring deoxyribonucleoside triphosphate (dNTP) concentrations and S-adenosylhomocysteine (SAH) hydrolase activity, we have studied various types of human lymphoid cells and demonstrated in them the relative importance of the above two mechanisms of AdR toxicity. Treatment of normal resting peripheral blood lymphocytes in culture with AdR and dCF resulted in impaired viability. Although elevated dATP levels as well as decreased SAH hydrolase activities were both observed, the failure of a known inhibitor of ribonucleotide reductase (hydroxyurea) to produce toxicity, and the inability of deoxycytidine (CdR) to achieve a rescue effect, point to another mechanism, possibly inhibition of trans-methylation or ATP depletion being the more likely causes of toxicity in resting lymphocytes. The same mechanism may well account for the rapid and severe lymphopenia in patients treated with dCF. On the other hand, in cultured lymphoblasts in the exponential phase of growth. AdR and dCF produced marked inhibition of growth and cell death both in a Thy-ALL line and in a c-ALL line, in the absence of significant inhibition of SAH hydrolase, but with a substantial elevation in dATP concentrations and depressed levels of the other dNTP. Minor toxicity occurred in a proliferating B lymphoblast line despite almost complete inactivation of SAH hydrolase. These observations indicate inhibition of ribonucleotide reductase as the more likely mechanism of toxicity in rapidly proliferating lymphocytes. Other T-cells actively synthesizing DNA, such as PHA-stimulated or MLC activated lymphocytes and T-lymphoid colony forming cells, are also likely to be affected by the same mechanism. Indeed in PHA-stimulated lymphocytes, deoxycytidine caused significant although incomplete rescue from toxicity due to dCF and AdR. In patients with ADA deficiency or treated with ADA inhibitors, both mechanisms could be operative. These observations are also relevant to the possible use of dCF and AdR as immunosuppressive agents and for the removal of T-cells or residual Thy-ALL blasts from bone marr
Adenosine Deaminase Inhibitors↗
Disseminated petriellidiosis (allescheriasis) in a patient with refractory acute lymphoblastic leukaemia.
A case of disseminated petriellidiosis is presented. This complication occurred in a patient with refractory acute lymphoblastic leukaemia, who was receiving repeated courses of cytotoxic drugs, antibiotics and prolonged corticosteroid therapy. The diagnosis of infection by Petriellidium boydii was established by pathological and microbiological studies of a specimen obtained at open lung biopsy. The portal of entry was probably through the lung spreading later via the blood stream to the brain, thyroid and kidneys. The present case once again emphasises the importance of specific microbiological identification in definitive diagnosis. To our knowledge, only three cases of disseminated petriellidiosis have been reported and this case appears to be the first case with renal involvement.
Adult↗
[Angioimmunoblastic lymphadenopathy with dysproteinemia--a clinicopathological analysis of 12 cases].
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Adult↗
Inhibition of secretion of a mutant lipoprotein across the cytoplasmic membrane by the wild-type lipoprotein of the Escherichia coli outer membrane.
A globomycin-resistant mutant of Escherichia coli was found to produce a precursor of the major outer membrane lipoprotein (prolipoprotein), in which the glycine residue at position 14 within the signal peptide was replaced by an aspartic acid residue. The same mutation has been reported by Lin et al. (Proc. Natl. Acad. Sci. U.S.A. 175:4891-4895, 1978). The structural gene of the mutant prolipoprotein was inserted into an inducible expression cloning vehicle. When the mutant prolipoprotein was produced in lipoprotein-minus host cells, 82% of the unprocessed protein was found in the membrane fraction, with the remaining 18% localized in the soluble fraction. However, when the production of the mutant prolipoprotein was induced in the wild-type lpp+ host cells, only 31% of the mutant prolipoprotein was found in the membrane fraction, leaving the remaining 69% in the soluble, cytoplasmic fraction. In addition, the assembly of the wild-type lipoprotein in these cells was not affected, whether the mutant prolipoprotein was produced or not. These results suggest that secretions of both mutant and wild-type prolipoproteins utilize the same component(s) responsible for the initial stages of secretion across the cytoplasmic membrane. However, it appears that the wild-type lipoprotein has a higher affinity for these components than does the mutant lipoprotein.
Anti-Bacterial Agents↗