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Biomedical subjects

R M Adams

Publications and source records attributed to R M Adams.

At least 55 records · Page 3Linked to original sources
PubMed1989

Mycosis fungoides in relation to environmental exposures and immune response: a case-control study.

Mycosis fungoides is a cutaneous T-cell lymphoma of unknown etiology, thought to be a rare sequela of chronic antigenic stimulation that may occur, for example, with exposure to contact allergens. To explore this possibility, we interviewed 174 patients with mycosis fungoides and 294 randomly selected control subjects in the San Francisco, Los Angeles, and Seattle areas concerning their lifetime histories of employment, chemical exposures, allergy, atopy, and certain medical conditions. Patients reported higher prevalence of cancers other than the non-Hodgkin's lymphomas and skin cancers (relative risk = 3.3, P less than .001) and were more likely than controls to burn when exposed to the sun (for nonblacks, relative risk = 1.7, P = .01). The latter difference may reflect a manifestation rather than a precursor of the disease. We found no consistent or biologically plausible differences between patients and controls with respect to types of jobs held, or to occupational or vocational exposures to chemicals. These findings do not support the hypothesis that persistent antigenic stimulation by contact allergens is etiologically important in the pathogenesis of mycosis fungoides.

Case-Control Studies↗
PubMed1989

Prevalence and relevance of allergic reactions in patients patch tested in North America--1984 to 1985.

Between Jan. 1, 1984, and May 1, 1985, 1199 patients with suspected allergic contact dermatitis were patch tested with 32 "standard" allergens, 707 patients with 19 "vehicle and preservative" allergens, and 613 patients with 10 "special study" allergens. Ten dermatologists representing nine geographic centers collected and analyzed data with the use of the American Academy of Dermatology's mainframe computer in Evanston, Illinois. The most common sensitizers identified were nickel, p-phenylenediamine, quaternium-15, neomycin, thimerosal, formaldehyde, cinnamic aldehyde, ethylenediamine, potassium dichromate, and thiuram mix. Each positive reaction was assessed for its clinical relevance.

Adult↗
PubMed1989

Panels of allergens for specific occupations.

It is important to have available panels of materials for patch testing patients working in specific occupations. Although it is not essential in every case to test with each substance listed on a given panel, careful consideration of the patient's work environment should suggest the specific test items that will provide the highest diagnostic yield in cases of allergic contact dermatitis.

Allergens↗
PubMed1989

Contact allergic dermatitis to dicyclohexylcarbodiimide used in protein synthesis.

Dicyclohexylcarbodiimide is a commonly used coupling agent found in protein synthesis. It is a potent allergic sensitizer found especially in the emerging industries involved in recombinant DNA synthesis. Chemists who work in research and development of this industry are especially at risk of development of contact dermatitis, unless they are careful and avoid skin contact. This report describes two chemists with allergic contact dermatitis from repeated contact with this compound in their work as research and development chemists. An appropriate concentration for patch testing is suggested.

Adult↗
PubMed1989

Expression and nucleotide sequence of the Lactobacillus bulgaricus beta-galactosidase gene cloned in Escherichia coli.

The Lactobacillus bulgaricus beta-galactosidase gene was cloned on a ca. 7-kilobase-pair HindIII fragment in the vector pKK223-3 and expressed in Escherichia coli by using its own promoter. The nucleotide sequence of the gene and approximately 400 bases of 3'- and 5'-flanking sequences was determined. The amino acid sequence of the beta-galactosidase, deduced from the nucleotide sequence of the gene, yielded a monomeric molecular mass of ca. 114 kilodaltons, slightly smaller than the E. coli lacZ and Klebsiella pneumoniae lacZ enzymes but larger than the E. coli evolved (ebgA) beta-galactosidase. The cloned beta-galactosidase was found to be indistinguishable from the native enzyme by several criteria. From amino acid sequence alignments, the L. bulgaricus beta-galactosidase has a 30 to 34% similarity to the E. coli lacZ, E. coli ebgA, and K. pneumoniae lacZ enzymes. There are seven regions of high similarity common to all four of these beta-galactosidases. Also, the putative active-site residues (Glu-461 and Tyr-503 in the E. coli lacZ beta-galactosidase) are conserved in the L. bulgaricus enzyme as well as in the other two beta-galactosidases mentioned above. The conservation of active-site amino acids and the large regions of similarity suggest that all four of these beta-galactosidases evolved from a common ancestral gene. However, these enzymes are quite different from the thermophilic beta-galactosidase encoded by the Bacillus stearothermophilus bgaB gene.

Amino Acid Sequence↗
PubMed1988

Subchondral cystic lesions (osteochondrosis) of the femoral heads in a horse.

Bilateral subchondral cystic lesions of the femoral head in a horse resulted in lameness. The lesions had resulted in degenerative disease in the left coxofemoral joint. The cause of lameness was confirmed by use of intra-articular anesthesia, joint fluid analysis, and radiography. Subchondral cystic lesions involving the femoral head should be considered in the differential diagnosis of equine lameness localized in the upper portion of the hind limb.

Animals↗
PubMed1988

The case for patch test readings beyond day 2. Notes from the lost and found department.

Additional patch test readings taken after 2 days (48 hours) are valuable in distinguishing false-positive reactions, which may occur up to 22% of the time. Second readings taken on days 3 through 7 may detect an additional 34% positive reactivity. Those reactions, both lost (initially positive, later negative) and found (initially negative, later positive) by delayed readings, require clinical correlation for relevance as do the readings that persist at and beyond day 2 (positive at both readings).

Allergens↗
PubMed1988

Medicolegal aspects of occupational skin diseases.

Skin diseases, including chemical burns, are the most frequently reported of all occupational illnesses. More than 90 per cent of work-related dermatologic problems are contact dermatitis, and there is rarely anything about the location and appearance of these lesions to differentiate clearly from a dermatitis of nonoccupational origin. A complete and time-consuming history must therefore be taken, including documentation of nonwork activities.

Adult↗
PubMed1986

Contact allergen alternatives: 1986.

Repeated episodes of allergic contact dermatitis burden patients with disability and expense, as well as considerable discomfort. In this paper we describe safe and practical alternatives for allergens present on the 1984-1985 "standard patch test tray" of the American Academy of Dermatology. In addition, we have provided information on alternatives for other important and common allergens encountered today. For each allergen, in addition to the molecular weight, we have given the Chemical Abstracts Number (CAS). This will be especially useful when the American Academy of Dermatology has in operation its computerized data bank, cross-linking chemicals with commercial products. In the near future, a physician will be able to obtain rapidly either the ingredients of a given product, or a list of commercial products containing a specific allergen, or both. This information will increase immensely the importance of searching for allergens by patch testing.

Allergens↗
PubMed1986

Secretion and autoproteolytic maturation of subtilisin.

The sequence of the cloned Bacillus amyloliquefaciens subtilisin gene suggested that this secreted serine protease is produced as a larger precursor, designated preprosubtilisin [Wells, J. A., Ferrari, E., Henner, D. J., Estell, D. A. & Chen, E. Y. (1983) Nucleic Acids Res. 11, 7911-7925]. Biochemical evidence presented here shows that a subtilisin precursor is produced in Bacillus subtilis hosts. The precursor is first localized in the cell membrane, reaching a steady-state level of approximately equal to 1000 sites per cell. Mutations in the subtilisin gene that alter a catalytically critical residue (i.e., aspartate +32----asparagine), or delete the carboxyl-terminal portion of the enzyme that contains catalytically critical residues, block the maturation of this precursor. This block occurs when these mutant genes are expressed in B. subtilis hosts where the chromosomal subtilisin gene has been deleted. When the mutant B. amyloliquefaciens subtilisins are expressed in B. subtilis hosts that contain an intact chromosomal subtilisin gene, the mutant precursors are processed to a mature form and released to the medium. Such processing, in trans, of the precursor is also demonstrated in vitro by addition of active subtilisin. Thus, the release of subtilisin from the cell membrane is dependent on an autoproteolytic process that appears to be novel among secreted proteins.

Bacillus↗
PubMed1986

Allergic contact dermatitis: novel immunohistologic features.

Leu-8 is a novel antigen expressed by the majority of mature T cells and certain other cells. Recent studies of the allogeneic mixed leukocyte reaction indicate that both Leu-8+ and Leu-8- subsets of Leu-3+ T cells have important functions in cell-mediated immunity in vitro. In order to determine whether Leu-3+8+ and/or Leu-3+8- T cells are present in cell-mediated immune reactions in vivo, we studied the immunohistology of allergic contact dermatitis in 8 biopsies from 8 patients with positive patch tests and 3 biopsies from 2 patients with Rhus dermatitis. Both Leu-3+8+ and Leu-3+8- T cells were present in each biopsy. Only 1 case had a definite minority of the Leu-3+8+ subset. These results suggest that, analogous to in vitro systems, both Leu-8+ and Leu-8- subsets of Leu-3+ T cells are involved in cell-mediated immunity in vivo. HLA-DR+ keratinocytes were present in only 3 of 11 biopsies at days 3-7. No HLA-DQ+ keratinocytes were identified. We also confirmed prior findings that Leu-3+ cells are the predominant T-cell population, Langerhans cells are increased, and B cells and NK cells are rare. Furthermore, Tac and Ki-67 expression by T cells and Leu-3 expression by Langerhans cells tended to increase over time.

Adolescent↗
PubMed1985

Effects of mechanical trauma on nails.

The nails are useful "tools" in many occupations, but because of their exposed position are vulnerable to mechanical and chemical traumas. This review deals with the common injuries and disorders of the nails in the workplace. Information is given regarding the occupations in which damage to nails is most likely to occur.

Hemorrhage↗
PubMed1985

A five-year study of cosmetic reactions.

During 64 months (1977 to 1983), twelve dermatologists from various sections of the United States studied a total of 713 patients with cosmetic dermatitis out of an estimated total of 13,216 patients with contact dermatitis. The number of patients seen for all causes during this period was 281,100. An important finding was that half of the patients or physicians were unaware that a cosmetic was responsible for their dermatitis. Skin care products, hair preparations (including colors), and facial makeup were responsible for the majority of the reactions. The most important objective was identification of causative ingredients. Eighty-seven percent of the subjects had patch tests. Fragrance, preservatives (Quaternium-15, formaldehyde, imidazolidinyl urea, and parabens), p-phenylenediamine, and glyceryl monothioglycolate were the most frequently identified allergic sensitizers, in that order. In addition to the clinical data, the study permitted assessment of the frequency of cosmetic reactions, although the data may not be entirely representative of the country at large because of the special interests of the dermatologists involved.

Adult↗
PubMed1984

Allergic contact dermatitis from rosin used as soldering flux.

Two cases of allergic contact dermatitis from soldering fluxes are reported. Both were caused by rosin (colophony). One case was confirmed by a positive patch test to rosin purchased from a commercial European patch test supplier. The other could be confirmed only by a positive patch test to the specific rosin used to flux the solder; repeated patch tests to rosin purchased from the same European supplier were negative. Dermatitis from soldering fluxes is reviewed.

Adult↗
PubMed1983

Implementing an industrial hearing conservation program in the schools.

The harmful effects of exposure to high noise levels have been well-documented and include auditory and non-auditory factors. The most notable auditory effect is permanent loss of hearing, many times accompanied by the constant perception of a ringing-type noise in the ears (tinnitus). Despite this, there has been insufficient attention given to the hazardous effects of noise in the school health education curriculum. The industrial arts program is one area that deserves special attention because of the noise levels that teachers and students are exposed to in the classroom and the assumed future exposure that students will experience in their recreational and work experiences. This report describes a hearing conservation program implemented in the Industrial Arts Program in the Dallas Independent School District that attempts to provide: 1) protection for students and teachers using equipment that produces excessive, damaging noise; and 2) information to students on the hazardous effects of noise, so they will understand the consequences of not protecting their ears when exposed to excessive noise and the available means to protect their hearing. As the cost of the program was minimal, other school districts could implement similar programs with little additional resources and effort.

Adolescent↗