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Biomedical subjects

D B Amos

Publications and source records attributed to D B Amos.

At least 19 recordsLinked to original sources
PubMed1999

Treatment of upper lip wrinkles: a comparison of 950 microsec dwell time carbon dioxide laser with unoccluded Baker's phenol chemical peel.

BACKGROUND: The high energy, pulsed, or computer-scanned continuous wave carbon dioxide laser (CO2 laser) has gained popularity as a wrinkle treatment because of its minimal thermal injury and precise control of tissue vaporization depth. Chemical peels such as phenol have also been effective in treating facial wrinkles. This is, to our knowledge, the first study comparing the use of CO2 laser to phenol for treatment of wrinkles on the upper lip. OBJECTIVE: To compare the effectiveness and side effect profile of the 950 microsec dwell time CO2 laser to that of unoccluded Baker's phenol chemical peel in the treatment of upper lip wrinkles. METHODS: Twenty female subjects with moderate to severe upper lip wrinkles were randomly treated with Baker's phenol on one side of the upper lip and the 950 microsec dwell time CO2 laser on the other side. RESULTS: The average upper lip laser-treated wrinkle score (0 = none to 5 = severe) decreased from 4.30+/-0.20 before treatment to 1.11+/-0.28 at 6 months after treatment. The average upper lip phenol-treated wrinkle score decreased from 4.20+/-0.20 to 0.47+/-0.12. The degree in which the wrinkle score improved after phenol treatment compared with that after laser treatment was statistically significant (p<0.03). CONCLUSION: Treatment of upper lip wrinkles with Baker's phenol resulted in greater improvement than treatment with the 950 microsec dwell time CO2 laser.

Aged↗
PubMed1999

Treatment of upper lip wrinkles: a comparison of the 950 microsec dwell time carbon dioxide laser to manual tumescent dermabrasion.

BACKGROUND: High-energy pulsed or computer-scanned continuous-wave carbon dioxide (CO2) laser resurfacing has gained popularity as a wrinkle treatment because of its minimal thermal injury and precise control of tissue vaporization depth. Manual tumescent dermabrasion has also been effective for treating facial wrinkles. This is, to our knowledge, the first study comparing the use of CO2 laser to manual tumescent dermabrasion for the treatment of wrinkles on the upper lip. OBJECTIVE: To compare prospectively the clinical efficacy of the 950 microsec dwell time CO2 laser to that of manual tumescent dermabrasion in the treatment of upper lip wrinkles. METHODS: Twenty female subjects with moderate to severe upper lip wrinkles were randomly treated with the 950 microsec dwell time CO2 laser on one side of the upper lip and manual tumescent dermabrasion on the other. RESULTS: The average upper lip laser-treated wrinkle score (0 = none to 5 = severe) decreased from 4.3 +/- 0.2 before treatment to 1.8 +/- 0.3 at 6 months after treatment. The average upper lip dermabrasion-treated wrinkle score decreased from 4.4 +/- 0.2 to 1.5 +/- 0.3. The degree to which the wrinkle score improved after laser treatment compared with that after dermabrasion was not statistically significant (P =.216). CONCLUSION: Manual tumescent dermabrasion and 950 microsec dwell time CO2 laser resurfacing are equally effective for the treatment of upper lip wrinkles.

Aged↗
PubMed1993

Rapid HLA-DR oligotyping by an enzyme-linked immunosorbent assay performed in microtiter trays.

A simple, sensitive ELISA that is performed in 96-well microtiter plates and that requires less than 90 minutes to complete was developed for HLA-DRB oligotyping. The second exon of HLA-DRB1 was amplified using an unlabeled forward primer and a biotinylated reverse primer and the PCR product was immobilized in avidin-coated wells. Subsequent treatment included exposure to 0.4 N NaOH to remove the nonbiotinylated sense strand, addition of a fluorescein-labeled oligonucleotide probe, one or more 5-minute stringency washes, addition of an alkaline-phosphatase-labeled anti-FL FAB, and then alkaline-phosphatase substrate and amplifier. An intense red-violet color developed within 15 minutes in positive wells and could be quantitated by OD readings at 490-495 nm. To control for stringency and to establish threshold OD values for positive reactions, biotin-labeled antisense oligos that were complementary to the probe or that differed by one or more bases were immobilized in wells in place of PCR products. The assay was sensitive to < 0.05 pmol (approximately 4 ng)/well and required only standard incubators and waterbaths and an optional microplate reader. All reagents were commercially available. The method should facilitate oligotyping of both class I and class II alleles and is adaptable for analysis of other polymorphic gene products.

Base Sequence↗
PubMed1989

Epitopes within the HLA-B5,B35 cross-reacting group.

The HLA-B5,B35 cross-reacting group is a large and serologically complex antigen family which includes the World Health Organization-recognized specificities HLA-B5,B51,Bw52,B35,Bw53,B18,Bw70,Bw71, and Bw72. In addition, several variants of antigens in this cross-reacting group have been described in the past but have not yet gained official recognition. A genetic basis for the complexity and the protein and molecular bases of this highly cross-reactive and polymorphic cross-reacting group have yet to be established. The potential contributions of shared amino acid sequences, the occurrence of multiple epitopes on a single HLA-B molecule, and the presence of new HLA-C antigens have been difficult to resolve. To address this issue, we have carefully examined the serologic reactions of more than 900 allo- and monoclonal antibodies (Tenth International Workshop, Third Asia-Oceanic Workshop, and local reagents) versus lymphocytes from 92 individuals of diverse ethnic origin (North American Caucasians, North American blacks, Amerindians, Middle Eastern Caucasians), 84 of whom were informative for the HLA-B5,B35 cross-reacting group and related antigens. Our results demonstrate that the HLA-B5,B35 gene products share different combinations of distinct epitopes. We have constructed a model for the evolution of this cross-reacting group by assigning polarity to distinct diversification steps utilizing principles of maximum parsimony.

Antibodies, Monoclonal↗
PubMed1987

The role of class I histocompatibility antigens in the regulation of T-cell activation.

Class I major histocompatibility antigens in humans (HLA antigens) were found to participate in the regulation of T-cell activation and proliferation induced by phytohemagglutinin. W6/32, a monomorphic antibody directed against class I HLA-A,B,C antigens, significantly inhibited the phytohemagglutinin-induced cell proliferation of peripheral blood lymphocytes. Almost complete suppression of cell activation was achieved on a subfraction of peripheral blood lymphocytes enriched in Mo1+ monocyte/macrophage cells. This inhibition of cell proliferation takes place at an early stage of activation and was found to be adherent cell dependent. Removal of monocyte/macrophage type cells from peripheral blood lymphocytes completely abrogated the inhibitory influence of anti-HLA-class I antibody, and, upon adding them back, suppression reappeared. Indirect immunofluorescence demonstrated that the expression of receptors for interleukin 2 and transferrin was impaired in the presence of antibody. Although the amount of interleukin 2 synthesized by these cells was also reduced, the addition of exogenous purified interleukin 2 did not restore cell proliferation. Mitogenesis induced by the Ca2+ ionophore A23187 was similarly suppressed, but mitogenesis induced by the phorbol diester phorbol myristate acetate, which activates cells by directly stimulating protein kinase C, was not suppressed. These results are consistent with a hypothesis that HLA class I antigens regulate an early event(s) of the Ca2+-dependent pathway of activation of T lymphocytes and that this event(s) apparently occurs before protein kinase C stimulation.

Antibodies↗
PubMed1987

Genetic and immunologic basis of atopic responses.

We summarize current understanding of the genetics of human diseases and of the major histocompatibility complex related factors regulating immune responsiveness. Special factors are involved in atopic diseases as a result of the intersection between the immune system, the targets in the tracheobronchial tree and the endocrine, neurologic and genetic mechanisms affecting both the effectors and the targets. The evidence from investigations of human subjects and their families and from laboratory animals for the underlying genetic and immunologic mechanisms of asthma are reviewed. The genetic control of asthma is complex. The evidence suggests a gene or genes associated with and linked to HLA. The disease phenotype may also be regulated by genetically determined levels of IgE and the outcome of the balance between immune response and immunosuppression.

Animals↗
PubMed1986

A mutation in a non-MHC murine cell surface antigen detectable by cytotoxic T lymphocytes.

During the course of screening new T-H-2 region congenic strains of mice constructed from the C57BL/6 and B6-H-2k strains, a new cell surface polymorphism, designated dtc-1, was identified by cell-mediated lympholysis techniques. The dtc-1 antigen can be found on both Con A- and LPS-stimulated lymphoblasts, peritoneal macrophages, and SV40-transformed mouse embryo fibroblasts. Lysis of dtc-1+ targets by CTL is H-2Dk restricted. All inbred strains tested are dtc-1+, with the exception of the B6-H-2k strain, which is dtc-1-, and several congenic strains directly derived from B6-H-2k. Because B6/Boy and AKR/Boy, the parents of the B6-H-2k strain, are dtc-1+, the dtc-1- phenotype may be the result of mutation in the locus specifying the cell surface molecule that carries this antigen. Segregation analysis of the dtc-1+/dtc-1- polymorphism demonstrated that this locus is not linked to T or H-2. The dtc-1 antigen thus identifies yet another cell surface polymorphism and adds another immunologically defined genetic marker to the murine genome. Furthermore, the dtc-1 system indicates the need for reevaluation and restandardization of congenic strains of mice derived from the B6-H-2k congenic strain.

Animals↗
PubMed1986

Functional defect of heat-inactivated human lymphocytes in mixed-lymphocyte culture.

Possible causes were examined for the inability of heat-inactivated lymphocytes to induce proliferative responses in mixed-lymphocyte cultures (MLC). Cells heated at 45 degrees C for 60 min lost greater than 90% of their capacity to stimulate in primary (1 degree) or secondary (2 degrees) MLC. This was not due to accelerated or delayed proliferation, nor to a simple quantitative loss of antigen since a 10-fold increase in stimulators or sequential addition of heated stimulators at 4-hr intervals was ineffective. Heated B lymphocytes had approximately 80% expression of HLA-DR and DQ antigens compared to unheated B cells when measured by flow cytometry using monoclonal antibodies detecting both monomorphic and polymorphic antigens. Contrary to some reports, there was no evidence of direct suppression or induction of suppression by heated stimulators or their supernatants. Reconstitution of 1 degree and 2 degrees MLC with crude MLC supernatants or more purified interleukin 1 (Il-1) or interleukin 2 (Il-2) was unsuccessful. The results indicate the heat-induced defect occurs immediately and is not due to direct or indirect suppression, insufficient amounts of Il-1 or Il-2, nor loss of polymorphic Class II HLA determinants. Heat inactivation of stimulator function may result from failure to present an "immunogenic grid" or loss of accessory molecules required in lymphocyte interactions.

B-Lymphocytes↗
PubMed1985

HLA studies of Highland and Coastal New Guineans.

The HLA profile of three New Guinean populations, two Highland (Asaro, Watut), and one Coastal is presented. The Highland populations are characterized by a low average number of alleles segregating at the HLA loci and also by a low mean value of heterozygosity at these loci. The genetic affinities of the two Highland groups with other Melanesian populations in the Pacific are remote. The Coastal group, on the other hand, shows strong similarities in its antigenic diversity and haplotypic combinations with other Melanesian populations. Nonetheless, the two Highland groups show significant divergence from each other in terms of allelic and haplotypic frequencies. Two different waves of migration settled in the Highlands of New Guinea between 10,000 and 15,000 years ago, and it is possible that the Watut, an Angan speaking group, represents the remnants of the first migration into the interior, whereas the Asaro, members of the Eastern Central family of the Trans-New Guinea phylum, arrived at a later date.

Adult↗
PubMed1984

HLA-DR7-specific monoclonal antibodies and a chimpanzee anti-DR7 serum detect different epitopes on the same molecule.

We describe here two monoclonal antibodies with HLA-DR7 serologic specificity. The antibodies, SFR16-DR7M, a cytotoxic rat IgM antibody of high affinity, and SFR16-DR7G, a noncytotoxic antibody of the rat IgG 2a class, react with only DR7-positive cells in radioimmunoassay. The cytotoxic activity of SFR16-DR7M correlates completely with the presence of the DR7 specificity, and segregates with the DR7-bearing haplotype in a family. SFR16-DR7M precipitates a class II molecule with the electrophoretic characteristics of DR molecules from LG-10, an HLA-DR7 homozygous cell line. SFR16-DR7G completely inhibits the cytotoxicity of SFR16-DR7M, but only partially inhibits the cytotoxicity of a chimpanzee antiserum with DR7 specificity, Gay/Swei. In binding-inhibition studies, binding of SFR16-DR7M to LG-10 cells is only partially inhibited by the chimpanzee antiserum and vice versa. Both SFR16-DR7M and Gay/Swei reciprocally deplete the same class II molecules from a 35S-methionine-labeled detergent-solubilized membrane preparation of the LG-10 cell line. The chimpanzee serum Gay contains antibodies reactive with epitopes on separated DR7 beta chains, while both SFR16-DR7M and SFR16-DR7G bind only to DR7 alpha-beta complexes. These data suggest that at least two allogenic epitopes exist which result in the same serologic specificity, and that these epitopes differ in their requirement for alpha-beta complex formation.

Animals↗
PubMed1984

H-2 antigens of certain t and non-t mice react with the same monoclonal antibody.

Monoclonal antibody 212.i.4.2 mediated complement-dependent lysis of spleen and lymph node cells carrying the tw1 , tw12 , tw71 , t6, tw73 , and tLub1 haplotypes, while cells from mice carrying 11 other t haplotypes were not lysed. The antibody also detected an epitope controlled by genes in the H-2Dd region of non-t mice. A molecule of 46,000 molecular weight was immunoprecipitated by 212.i.4.2 from detergent extracts of 125I-labelled spleen cells of +/ tw12 and B10.D2 mice. The H- 2dm2 mutation did not alter the expression of the epitope recognized by 212.i.4.2. However, the H- 2dm1 mutation decreased the reactivity of lymphoid cells with the antibody in cytotoxicity tests, and 212.i.4.2 immunoprecipitated little or no protein from extracts of B10.D2( R106 ) spleen cells which carry the H- 2dm1 mutation.

Animals↗
PubMed1983

The inheritance of immunoglobulin E: genetic linkage analysis.

Linkage analyses between 21 genetic markers including HLA-A, B, and the postulated locus for determining total serum IgE levels were done to try to clarify the inheritance of total IgE levels and to map the locus. A total of 316 individuals from five Mormon kindreds were studied, and data from an additional 204 Amish individuals from 11 families were analyzed for possible HLA linkage. Segregation analyses of both data sets did not give clear definition of the mode of inheritance of total IgE levels, but purely environmental models were rejected. Linkage analyses gave significant evidence against HLA linkage with the codominant, recessive, or dominant model of inheritance for total IgE levels. No significant evidence for linkage with any of the genetic markers was obtained. Since total serum IgE levels are correlated with allergies, understanding the genetics of total IgE levels is important to understanding the genetics of allergic disease in man.

Blood Group Antigens↗
PubMed1983

Genetic analysis of the T-H-2 region in non-t chromosomes. I. Two new congenic strains isolate Qglo-1 from H-2.

A general breeding protocol useful in the construction of congenic lines of mice disparate in the 15 cM T-H-2 region of chromosome 17 in non-t chromosomes is described. Two such congenic lines, B6.TC2/Rn and B6.TC3/Rn, were derived from the C57BL/6J and B6.C-H-2d/By strains using this protocol. Both B6.TC2 and B6.TC3 dissociate the quantitative activity locus for glyoxalase I (Qglo-1) from the H-2 complex, and hence possess BALB/cBy DNA centromeric to H-2. However, neither new strain is able to map any H-2-associated restriction fragment length polymorphism with an H-2 cDNA probe even though both strains are recombinant in the 2 cM Qglo-1-H-2K interval.

Animals↗