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Biomedical subjects

S Lam

Publications and source records attributed to S Lam.

At least 199 records · Page 11Linked to original sources
PubMed1980

Ethylenediamine-induced asthma.

A patient with asthma due to exposure to ethylenediamine was described. He was exposed to a large number of chemicals used in developing color photographs. He developed a specific and reproducible late asthmatic reaction after occupational-type exposure test to ethylenediamine. Exposure to other chemicals, such as formaldehyde and Kodak developers CD2 and CD3 (p-phenylenediamine derivatives), did not induce any asthmatic reaction. Result of a skin test with ethylenediamine was negative, and precipitating antibodies to this chemical were not found. The late asthmatic reaction was not accompanied by an increase in the venous plasma concentration of histamine. The mechanism of the late asthmatic reaction to ethylenediamine is unknown. An immunologically mediated mechanism cannot be excluded. However, intrinsic bronchial hyperreactivity is probably not an important predisposing factor, because bronchial reactivity decreased and approached the normal range after the patient was removed from further exposure. Ethylenediamine released histamine in studies in vitro from the whole blood of patients as well as in those of 2 unexposed subjects. The role of direct, histamine release in the pathogenesis of asthma has yet to be determined. This is another example of late asthmatic reaction induced by a low-molecular-weight compound.

Adult↗
PubMed1980

Interrelationships between serum chemotactic factor inactivator, alpha 1-antitrypsin deficiency, and chronic obstructive lung disease.

Serum chemotactic factor inactivator (CFI) activity was quantitated in 22 subjects with chronic airflow obstruction (CAO); 8 had normal antitrypsin levels (Pi M phenotype), 6 had intermediate antitrypsin deficiency (Pi MZ phenotype), and 8 had severe antitrypsin deficiency (Pi Z phenotype). We studied 19 healthy subjects with normal lung function as controls; 3 had Pi M and 6 had Pi MZ phenotypes. Subjects with CAO, irrespective of the alpha 1-antitrypsin (AAT) phenotype, had significantly lower CFI activity than the normal subjects; the lowest levels were found in those with CAO and Pi Z phenotype. Normal subjects with intermediate AAT deficiency and MZ phenotype had normal levels of CFI. The results suggest that deficiency of serum CFI may be important in the pathogenesis of chronic airflow obstruction, particularly in those with severe AAT deficiency.

Adult↗
PubMed1979

In vitro drug resistance of salmonellae in Singapore.

Strains of Salmonella typhi isolated in Singapore were susceptible to chloramphenicol (except from two imported cases) and most of them also generally susceptible to ampicillin and septrin. Drug-resistant strains of Salmonella typhimurium appeared in 1971 and caused out-breaks among young children. However, decreasing drug-resistance of S. typhimurium was recorded in recent years following a drop in the number of cases. Other Salmonella serovers were found relatively susceptible to the antibiotics tested.

Anti-Bacterial Agents↗
PubMed1977

Multiple myeloma with cutaneous involvement.

A 49-year-old man with multiple myeloma, IgA type, contracted cutaneous plasmocytomas. No deposits of immunoglobulin were found in the cutaneous tumor by direct immunofluorescence. The case is an unusual manifestation occurring in multiple myeloma.

Fluorescent Antibody Technique↗
PubMed1975

Retention of antimelanoma effect of polyinosinic-polycytidylic acid in neonatally thymectomized, irradiated, leukopenic mice.

Polyinosinic-polycytidylic acid (PIC), a synthetic polyribonucleotide, inhibits the growth of B16 malignant melanoma in C57BL/6 mice. Since PIC has been reported to augment immune responses, we tested the hypothesis that the antitumor effect of PIC against B16 melanoma is via immune stimulation. Mice were neonatally thymectomized or neonatally thymectomized and subsequently irradiated to suppress their immune reactivity. In such animals PIC retained its ability to inhibit the growth of B16 melanoma, in the face of profound leukopenia and lymphopenia, suggesting that its antimelanoma effect is probably not mediated by augmentation of the host's immune antitumor response.

Animals↗
PubMed1974

The distribution of crossovers along unreplicated lambda bacteriophage chromosomes.

The distribution of crossovers along unreplicated chromosomes of bacteriophage lambda has been examined by determining the density distributions and genotypes of particles in the progenies of crosses of density-labeled by ordinary parents in the presence of genetic blocks to replication. The Red and Rec systems combined produce crossovers primarily near the ends (especially the right end) of the chromosome. Removal of the generalized lambda recombination functions by red and gam mutations results in loss of these terminal crossovers; coupled with this loss is a disappearance of the differential dependence of recombination frequencies in terminal and central intervals on DNA synthesis. Removal of the bacterial system by a recA mutation results in severe depression of crossing over among unreplicated phage, with the few recombinants produced by the lambda system occurring near the right end.

Chromosome Mapping↗