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Biomedical subjects

M Stapleton

Publications and source records attributed to M Stapleton.

15 recordsLinked to original sources
PubMed1996

MADR1, a MAD-related protein that functions in BMP2 signaling pathways.

Components of the signaling pathways that lie downstream of Ser/Thr kinase receptors and are required for signaling by the TGF beta superfamily have been poorly defined. The Drosophila gene Mothers against dpp (MAD) and the C. elegans sma genes are implicated in these signaling pathways. We show that MAD functions downstream of DPP receptors and is required for receptor signaling. Phosphorylation of MADR1, a human homolog of MAD, is tightly regulated and rapidly induced by BMP2, but not TGF beta or activin. This phosphorylation is necessary for function, since a point mutant that yields a null phenotype in Drosophila is not phosphorylated. BMP2 treatment results in accumulation of MADR1 in the nucleus. MAD proteins may thus define a novel class of signaling molecules with nuclear function in Ser/Thr kinase receptor signaling pathways.

Activins↗
PubMed1995

Communitywide shigellosis: control of an outbreak and risk factors in child day-care centers.

OBJECTIVES: The study's objectives were to assess (1) control of a community outbreak of shigellosis through the promotion of handwashing, (2) risk factors in day-care centers, and (3) shigellosis attributable to attendance at a day-care center. METHODS: In 1991, an outbreak of Shigella sonnei infections occurred in Lexington-Fayette County, Ky; 14 licensed child day-care centers were involved. Communitywide promotion of hand washing was instituted along with diarrhea surveillance. A case-control study compared day-care centers that had confirmed cases of shigellosis with centers that had none. A family transmission study determined those cases attributable to attendance at day-care centers. RESULTS: The outbreak abated 3 weeks after the interventions' initiation. Day-care centers with outbreaks were more likely than those with no cases to have a food handler who changed diapers and to provide transportation for children from their homes to the center. These centers also had a higher toddler-to-toilet ratio than control centers (21 vs 12). In 58% of families with shigellosis, the first person with diarrhea during the outbreak was a child younger than 6 years; 92% of diarrheal illnesses among these children were attributable to day-care attendance. CONCLUSIONS: Community involvement in increasing hand washing most likely resulted in control of this shigellosis outbreak. Diarrhea prevention strategies in day-care centers could prevent substantial communitywide disease.

Case-Control Studies↗
PubMed1992

Adjuvanticity and ISCOM formation by structurally diverse saponins.

Adjuvant activity and immunostimulating complex (ISCOM) formation by a series of saponins and glycoalkaloids differing in the structures of their aglycones and sugar chains were examined. The only two saponins apart from Quillaia that were adjuvant-active were Gypsophila and Saponaria, which resemble Quillaia in that they contain saponins with branched sugar chains attached to positions 3 and 28 of the aglycone. Glycoalkaloids with a branched sugar chain lacked adjuvant activity. Saponaria saponins formed irregular ISCOM-like structures, and Gypsophila produced a sheet of joined pore-like structures. The alfalfa hederagenin saponin and Quinoa also formed pore-sheets, despite lacking adjuvanticity.

Adjuvants, Immunologic↗
PubMed1992

The control of the antibody isotype response to recombinant human immunodeficiency virus gp120 antigen by adjuvants.

Both saponin and muramyl dipeptide (MDP) formulated with a squalane-in-water emulsion of large particle size prepared with a vortex mixer were superior to Al(OH)3 as adjuvants for HIV gp120 in mice. All the adjuvants induced IgG1 antibody, but saponin elicited the highest titers of IgG2a. The secretion of interleukin-5 (IL-5) and interferon gamma (IFN gamma) by lymph node cells cultured in vitro with gp120 was studied. All the cultures secreted IL-5, but only those from saponin-immunized mice produced IFN gamma, suggesting that saponin is capable of activating both the Th1 and TH2 T-cell subsets. The titers of neutralizing antibodies were low with both MDP and saponin, and they occurred in mice which were also positive for antibodies against a V3 loop peptide. Glucosaminylmuramyl dipeptide (GMDP) which is less pyrogenic than MDP and a nonpyrogenic analog GMDPA, displayed equivalent adjuvant activity to MDP. The level and isotype composition of antibodies induced by GMDP in combination with squalane emulsions depended on the dimension of the emulsion particles. With a large (2500 nm) particle size the response was confined to IgG1 in Balb/c mice, but when this was reduced to 150 nm by sonication the antibody response was increased and relatively high levels of IgG2a appeared in some mice.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1992

Dithranol allergy: fact or fiction?

A case of a psoriatic patient allergic to dithranol and coal tar is described. It is suggested that dithranol 0.001% pet. is a suitable concentration to test for dithranol allergy, as higher concentrations may produce irritant reactions. The literature on dithranol allergy is reviewed and the frequent simultaneous reactions to dithranol and coal tar discussed.

Anthralin↗
PubMed1992

Survival of persons with AIDS in Kentucky.

Of all reported Kentucky adult/adolescent cases of AIDS (124) with diagnosis dates from July 1, 1990, through June 30, 1991, 33% died within three months of diagnosis. To discern possible reasons for these very short survival times, information was analyzed from the CDC AIDS Confidential Case Report of the 124 patients and from the hospital charts of the 29 patients who were reported as having died within the month of or the month following diagnosis. Data suggested that survival for three months appears to be less likely for blacks, for males, and for those 30 through 34 years old. In the cohort the first diagnosis of AIDS was made at 40 different hospitals and the patients presented to 77 different physicians. Of chart-reviewed patients, 16 of the 29 (55.1%) were previously known to be HIV-positive. The most commonly identified likely reason for short survival time from AIDS diagnosis to death was that the diagnosis had been previously missed (10 of the 29 patients--34%). The study showed that many known to be HIV-positive for some time had apparently received little or no care for their infection from testing until diagnosis with AIDS. Medical review of patient charts suggested that scatter of caregivers may have resulted in some errors in diagnosis and treatment decisions. Also, considerable numbers of persons with HIV infection are either not utilizing the existing HIV counseling, testing, and follow-up systems or are not receiving medical care for their infection once it is identified.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Genomic structure of Chlamydomonas caltractin. Evidence for intron insertion suggests a probable genealogy for the EF-hand superfamily of proteins.

A clone containing the gene locus for Chlamydomonas caltractin, a 20,000 Mr calcium-binding protein that is a member of the EF-hand superfamily of calcium-modulated proteins, was isolated and the structural organization of the gene was determined. The intron-exon organization was resolved by direct comparison of the genomic sequence with a caltractin cDNA. The promoter region does not contain the typical TATA or CCAAT boxes, but the sequences at the splice junctions are similar to those of other eukaryotes. The positions of the six introns in the caltractin gene do not typically define unit structures, nor do they coincide with those in genes for other members of the EF-hand superfamily. An analysis of exon sequences at the splice junctions in the genes of this multigene family was undertaken; evidence was obtained that supports the hypothesis that introns arose at proto-splice sites. A probable evolutionary history for the EF-hand superfamily based on intron insertion is offered.

Amino Acid Sequence↗
PubMed1982

Serum elevation of high density lipoprotein (HDL) cholesterol in epileptic patients taking carbamazepine or phenytoin.

Serum lipids and the cholesterol concentration in the high density lipoprotein (HDL) fraction were measured in epileptic patients taking either carbamazepine or phenytoin as single drug treatment. There was a significant increase in HDL-cholesterol levels in patients taking both phenytoin and carbamazepine. Serum total-cholesterol concentrations in patients taking both drugs did not differ significantly from those of controls. The ratio of HDL-cholesterol/total cholesterol was increased in both drugs and the increase reached significance in patients taking phenytoin. There was a significant increase in serum triglycerides in females taking carbamazepine.

Adolescent↗
PubMed1981

Simple adaptation of the Technicon SMAC system to operate 18 channels with reduced volumes of plasma.

The Technicon SMAC system was adapted to function with much smaller volumes of plasma than those used in standard procedures. With only minimal operator-entered changes to the 7.6 computer program, and simple modifications of the glucose and alkaline phosphatase channels, the SMAC analyser performed equally well when the plasma volume was decreased from 235 microliter sequentially down through 176 microliter, 142 microliter, and 105 microliter. The basic principle employed was to maintain a constant flow rate of diluted sample plus diluent with decreasing sample size. The instrument proved to have the capability of operating successfully on all channels with lower signals than those encountered with the unmodified system.

Autoanalysis↗