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Biomedical subjects

R L Dobson

Publications and source records attributed to R L Dobson.

At least 55 records · Page 3Linked to original sources
PubMed1987

Neutron RBEs and the radiosensitive target for mouse immature oocyte killing.

The highly radiosensitive immature oocytes of mice were irradiated in vivo with graded doses of 252Cf fission radiation, 0.43- or 15-MeV neutrons, or 60Co gamma rays. Comparisons of oocyte survival for neutrons and for gamma rays demonstrate that neutron RBEs for the killing of these important cells do not reach the high values (30-50 or more) at low doses observed for several other biological end points. Rather, neutrons differ little in effectiveness from gamma rays in killing these extremely sensitive murine oocytes. For 0.43-MeV neutrons, RBEs obtained from fitted survival curves reach only 1.7 at 0.1 rad. For 15-MeV neutrons, they are not significantly different from 1 at any dose tested (lowest, 4.5 rad). For 252Cf fission neutrons (E = 2.15 MeV), RBEs are intermediate between those for 0.43- and 15-MeV neutrons. For all neutron energies tested, the RBEs are particularly low in the juvenile period, a time when murine immature oocytes are especially radiosensitive. With exposure just prior to birth, however, when these cells are much less easily killed, higher, more usual RBEs are found. The minimum size of the lethality target in mouse immature oocytes, estimated from the inactivation constant for 0.43-MeV neutrons and microdosimetric values, is larger than the nucleus but not larger than the cell. This and related analytical considerations suggest that the hypersensitive target in these particular oocytes is the plasma membrane, a finding which is in excellent accord with results from other experiments using different, contrasting radiations and dose deliveries (accelerated Si14+ ions, gamma rays, and beta rays from 3HOH compared with those from [3H]thymidine).

Animals↗
PubMed1986

Mononuclear cell phenotypes in patients with psoriasis.

Mononuclear blood cells from 19 patients with psoriasis were stained with a panel of monoclonal antibodies which detect total T lymphocytes, their helper/inducer and suppressor/cytotoxic subsets and Ia-positive lymphocytes and monocytes. Fluorescence-positive cells were enumerated by cell flow cytometry. In these patients, percentages of all mononuclear cell studies were within reference range with few, sporadic exceptions. Statistical analysis of data showed no significant differences between patient values and reference values from a panel of 100 normal subjects.

Adult↗
PubMed1985

An outbreak of contact dermatitis in farm workers.

Fourteen of twenty-six migrant workers developed contact dermatitis at a single tomato-strawberry farm in Tennessee. Investigation identified one of eleven pesticides used by the farmer, 2,4-dichloro-6-(o-chloroanilino)-s-triazine anilazine; Dyrene), as the cause of the dermatitis in six of seven workers who were available for patch testing. As a result of this investigation, the label on Dyrene has been revised to warn users of possible sensitization.

Adolescent↗
PubMed1985

Epidermal nuclear immunofluorescence: serological correlations supporting an in vivo reaction.

Epidermal nuclear deposits of immunoglobulins (Ig) were studied by direct immunofluorescence in three groups of patients: ten scleroderma (SD, systemic sclerosis), seven dermatomyositis (DM) and seven systemic lupus erythematosus (SLE). Each patient had skin biopsies taken from three different sites (nailfold, forearm, buttock) on the same day that a serum sample was also obtained. Epidermal nuclear deposits were observed in nine of twenty-four patients (five SD, two DM, two SLE). A high serum ANA titre correlated significantly with the presence of epidermal nuclear Ig deposits. The nucleolar epidermal nuclear pattern was limited to the SD group, four of ten patients showing this pattern. Two of nine patients with positive results in the nailfold and forearm had negative findings in the buttock, supporting the view that deposition of Ig in the epidermal nuclei occurs in vivo.

Adolescent↗
PubMed1985

Direct and indirect immunofluorescent findings in dermatomyositis.

Three skin biopsies (proximal nailfold, extensor forearm and buttock) and serum samples were studied by direct and indirect immunofluorescence, immunodiffusion and radioimmunoassay techniques in 6 patients with dermatomyositis. A variety of serologic and immunopathologic abnormalities was observed in the patients. Three of 6 patients had antinuclear antibodies (ANA) of a speckled pattern mixed with a peculiar dot pattern. Epidermal intercellular deposits of immunoglobulins were seen in the nailfold biopsies of 2 patients; one of them also had IgG deposits in the cytoplasm of epidermal cells. Forearm and buttock biopsies were negative.

Adolescent↗
PubMed1985

Fibronectin distribution in nailfold biopsies of scleroderma (systemic sclerosis) patients.

The distribution of fibronectin (FN) was studied in skin biopsies of 13 patients with scleroderma (SD), 7 patients with dermatomyositis (D), and 10 normal controls (NC) by direct immunofluorescence. In normal tissues, continuous or segmental linear staining of the dermal-epidermal junction (DEJ) was seen. Papillary, subpapillary dermis, and papillary capillary loops showed a reticular pattern of deposition with fibronectin. Scleroderma patients revealed similar staining in the dermis and DEJ. The reticular distribution of FN appeared to stain more intensely in the dermis than in controls, especially in deeper layers. The amount of FN in walls of blood vessels from SD patients was markedly increased; all dermal vessels stained with FN and revealed considerably thicker walls and larger lumens. FN distribution in DM patients was similar to that seen in SD with an increased amount of FN staining in capillary walls.

Adolescent↗
PubMed1985

Immunoglobulin E in psoriasis evaluated by paper radioimmunosorbent and paper enzyme-immunosorbent tests.

Serum IgE concentrations were determined by the paper radioimmunosorbent test in 56 patients with psoriasis and 50 normal controls, and by the paper enzyme-immunosorbent test in 32 of these patients and 50 controls. Elevated IgE levels were found in 26 (46%) of 56 patients with psoriasis and in 1 normal control (2%). The mean value (208 U/ml) in 56 patients was significantly higher than in normal controls (31 U/ml). Thirteen of 19 patients (68%) with extensive involvement (greater than 20% body surface) had an increased IgE level; the mean value (365 U/ml) was 4 times greater than in 17 patients with limited lesions (89 U/ml) and 12 times higher than in 50 normal controls (31 U/ml). No correlation was found between serum IgE levels and the presence of psoriatic arthritis. Both paper radioimmunosorbent and paper enzyme-immunosorbent testing produced similar results.

Adolescent↗
PubMed1985

Anticentromere antibody and immunoglobulin allotypes in scleroderma.

Fifty-five unrelated whites with disorders in the scleroderma spectrum who had both antinuclear antibodies and Raynaud's phenomenon (RP) were studied. Of the 22 patients with anticentromere antibody (ACA), three had diffuse scleroderma; 16 had the complete or incomplete syndrome of calcinosis, RP, esophageal dysmotility, sclerodactyly, and telangiectasia (CREST syndrome); and three had RP only. Thirty-three patients with other nuclear patterns all had systemic scleroderma (28 diffuse scleroderma, five CREST syndrome). Patients with ACA had less organ system involvement, and lower frequencies of anemia and elevation of sedimentation rate than ACA-negative patients, but these differences were not statistically significant. They also had fewer manifestations of CREST syndrome. All 55 patients were studied for the Gm and Km allotypic markers. No association was found between Gm or Km allotypic markers and scleroderma or between the allotypic markers and the presence of ACA.

Adolescent↗
PubMed1984

Association between fluorescent antinuclear antibodies, capillary patterns, and clinical features in scleroderma spectrum disorders.

Antinuclear antibody and in vivo capillary patterns were studied in 33 patients with Raynaud's phenomenon only and in 68 patients with scleroderma spectrum disorders; the results were correlated with clinical and laboratory findings. In addition, antinuclear antibody results in the groups with Raynaud's phenomenon only and scleroderma spectrum disorders were compared with those found in 70 patients with systemic lupus erythematosus (SLE). Distinct antinuclear antibody profiles were observed in the three diagnostic groups. Comparison of patients with anticentromere antibodies with others in the group with scleroderma spectrum disorders demonstrated that anticentromere antibody-positive patients tended to have a milder disease: less skin and visceral involvement, less frequent presence of hypertension, anemia, and elevated sedimentation rate. These differences did not, however, reach statistical significance. Comparison of patients with scleroderma spectrum disorders according to in vivo capillary patterns revealed that those with an "active" pattern had significantly more extensive skin involvement than those with a "slow" pattern. Visceral involvement tended to be greater in all organ systems in the group with an "active" pattern and reached statistical significance for muscle and kidney. Hypertension was also significantly more frequent in the group with an "active" pattern than in the group with a "slow" one. The latter was positively correlated with the presence of anticentromere antibody.

Adolescent↗
PubMed1984

Immune complexes and antinuclear, antinucleolar, and anticentromere antibodies in scleroderma.

Forty-one patients with various forms of systemic sclerosis (scleroderma) and positive antinuclear antibodies of nucleolar (ten patients), speckled (eleven patients), or centromere pattern (twenty patients) were selected for study of immune complexes by the radioisotope labeled Clq binding and the radioisotope labeled protein A binding methods. The presence of immune complexes was found by the Clq binding assay in sixteen patients (39%) and by a protein A binding assay in eight patients (20%). Overall, 46% of patients (19/41) had immune complexes. A lower incidence of organ involvement and fewer positive results in the screening of serum immune complexes were observed in patients with centromere antibody (35%) than in patients with nucleolar (60%) or speckled pattern (55%). Patients with immune complexes had higher frequencies of kidney, heart, and muscle involvement and digital ulceration than did patients with no detectable immune complexes, but the differences were not statistically significant. Diffuse skin involvement was not related to the presence of immune complexes.

Adult↗
PubMed1983

Gm allotypes in blacks with systemic lupus erythematosus.

Serum samples were collected from 328 healthy American Blacks and from 61 American Blacks with systemic lupus erythematosus (SLE). Sera were typed for the Gm1,2,3,5,6,13,17, and 21 allotypes as well as for the Km(1) allotype. The frequency of Gm phenotype 1,17;5,6,13 was significantly increased in the SLE patients (p = 0.0001, RR = 3.19, EF = 0.29). Our data suggest the existence of at least two immunoglobulin allotype associated genes that somehow interact to increase susceptibility to SLE in Blacks. To our knowledge, this is the first report of an association of Gm and SLE in Blacks.

Black People↗
PubMed1983

Female germ cell loss from radiation and chemical exposures.

Female germ cells in some mammals are extremely sensitive to killing by ionizing radiation, especially during development. Primordial oocytes in juvenile mice have an LD50 of only 6-7 rad, and the germ cell pool in squirrel monkeys is destroyed by prenatal exposure of 0.7 rad/day. Sensitivity varies greatly with species and germ cell stage. Unusually high sensitivity has not been found in macaques and may not occur in man, but this has not been established for all developmental stages. The exquisite oocyte radiosensitivity in mice apparently reflects vulnerability of the plasma membrane, not DNA, which may have implications for estimating human genetic risks. Germ cells can be killed also by chemicals. Such oocyte loss, with similarities to radiation effects, is under increasing study, including chemotherapy observations in women. More than 75 compounds have been tested in mice, with in vivo toxicity quantified by oocyte loss; certain chemicals apparently act on the membrane.

Administration, Oral↗
PubMed1981

Topical clindamycin therapy for acne vulgaris. A cooperative clinical study.

Eleven institutions participated in an eight-week controlled clinical study to evaluate treatment of acne vulgaris with topical clindamycin hydrochloride and clindamycin phosphate. Three hundred fifty-eight patients with comparable baseline pustule, papule, and nodule counts applied 1%, clindamycin hydrochloride, 1% clindamycin phosphate, or a hydroalcoholic vehicle twice daily. Every two weeks, lesions were counted, and patients' evaluations of their acne conditions were scored. By week 8, pustule and papule counts in the groups who were receiving clindamycin were significantly lower than those in the group receiving placebo. Also, more patients who were receiving clindamycin thought their acne improved by week 8 (with significantly higher change-in-acne scores) than did the patients receiving placebo. Patients receiving clindamycin reported 12 episodes of diarrhea; only one episode was considered to be treatment related. These results substantiate the clinical impression that topical clindamycin is effective treatment for acne.

1-Propanol↗
PubMed1981

Efficacy of halcinonide cream, 0.1 percent, in the treatment of moderate and severe dermatoses.

The efficacy of halcinonide cream, 0.1 percent, was evaluated in 101 patients with moderate or severe dermatoses. Conditions of these patients included contact dermatitis, atopic dermatitis, nummular eczema, neurodermatitis, stasis dermatitis, dyshidrosis, and various combinations of these disorders. Halcinonide cream was prescribed twice or three times a day for three weeks, and patients were followed-up weekly during this period. Sixteen patients stopped treatment after two weeks because their lesions had cleared. By the end of three weeks, the condition in 46 of the patients had completely resolved, the condition in 39 showed marked improvement, the condition in 10 had improved moderately, the condition in 5 showed mild improvement, and the condition in 1 did not show any improvement. No local or systemic side effects were reported. We conclude that halcinonide cream is an effective and safe topical therapy in the short-term treatment of a variety of moderate to severe steroid-responsive dermatoses.

Administration, Topical↗