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Biomedical subjects

R P Dawber

Publications and source records attributed to R P Dawber.

At least 19 recordsLinked to original sources
PubMed1992

Minoxidil-induced changes in the contraction of collagen lattices by human skin fibroblasts.

This investigation has studied the effect of minoxidil on the contraction of hydrated collagen lattices by human dermal fibroblasts. Type I collagen was mixed with a fibroblast suspension and polymerized, and minoxidil 10 to 800 micrograms/ml (0.05 to 4 mM) was added at the time the lattices were released. Minoxidil at concentrations from 100 to 600 micrograms/ml inhibited contraction in a dose-dependent manner, whereas 800 micrograms/ml prevented contraction completely, most cells remaining rounded. Considerable inhibition was already evident within 24 hours. Visualization of living cells with MTT and cell counts showed that inhibition in the first 48 hours was not due to fibroblast death. Exchange of minoxidil to normal medium led to a resumption of contraction and a return to an elongate morphology. Minoxidil at 10 micrograms/ml had no significant effect on lattice contraction, whereas at 100 micrograms/ml it slowed contraction without affecting proliferation or morphology, as observed under the light microscope. The inhibitory effect of minoxidil should be investigated further in relation to the control of contraction of wounds in vivo.

Adolescent↗
PubMed1992

Scarring alopecia in discoid lupus erythematosus.

The clinicopathological features of the scarring alopecia of discoid lupus erythematosus (DLE) were studied. Scarring alopecia was present in 34% of 89 patients with DLE and was associated with a prolonged disease course. More than half these patients had scalp involvement at the onset of the disease. There was a significant reduction in size of sebaceous glands in affected scalp. Perifollicular lymphocytic inflammation was maximal around the mid-follicle at the level of the sebaceous gland, which seems to be an important functional level in the follicle. There are changes in the expression of the matrix molecules, the proteoglycans, in the connective tissue sheath and the keratin intermediate filaments in the outer root sheath cells at this level in normal scalp and in diseased scalp. Loss of a population of mid-follicular stem cells may be important in the pathogenesis of scarring alopecia in DLE.

Adolescent↗
PubMed1992

Hereditary hypotrichosis (Marie-Unna type) and juvenile macular degeneration (Stargardt's maculopathy).

Hypotrichosis of the Marie-Unna variety is a distinctive syndrome eponymously named following a publication in 1925 describing a family in which 27 individuals in seven generations were affected by a previously unreported type of hypotrichosis. Its inheritance is determined by an autosomal dominant gene and it usually occurs as an isolated abnormality. Hereditary macular degeneration (Stargardt's maculopathy) is also well recognized and has been reported in one family in association with alopecia areata but never in association with Marie-Unna hypotrichosis. Inheritance of Stargardt's maculopathy is autosomal recessive. Our patient demonstrates the co-existence of these two uncommon genetic disorders and it would appear that both defects have been independently inherited.

Child↗
PubMed1992

An epidemiological profile of in-patient workload in dermatology.

Trends in admission rates, patterns of readmission, lengths of stay and clinical caseload for in-patient dermatology from 1976 to 1985 are described using data from the Oxford record-linkage study. Age-specific admission rates were considerably higher in people aged 50 years and over than in younger people. Admission rates declined over time in most age-sex groups below the age of 70 years, but increased over time for the over 70s. In dermatology, unlike most other specialties, the length of patients' stay did not decrease substantially over the 10 years. In-patient workload consisted predominantly of leg ulcers, psoriasis, and eczema. This did not change appreciably over time. New out-patients at dermatology clinics rose by 41% from 1976 to 1985, and all out-patient visits rose by 20% during the 10-year period. Because the profile of in-patient workload changed relatively little over time, we speculate that the impact of innovations in dermatological practice has been much greater in the ambulatory setting than in the management of those patients requiring prolonged in-patient care. Future routine measures of workload in dermatology should include demographic and clinical data on out-patients.

Adult↗
PubMed1992

Congenital inclusion dermoid cysts of the scalp.

The natural history of congenital inclusion dermoid cysts of the scalp is unknown. We report three cases of this condition, which has been followed from birth for up to ten years. Dermoids are congenital subcutaneous cysts, which gradually flatten and scar over a number of years. The lesions are covered with skin showing focal alopecia but they may be surrounded by a collar of hypertropic hair. Later in life flattened cysts may be mistaken for aplasia cutis, but the history of a cyst at birth allows the clinician to distinguish these two conditions. As these cysts have a potential for intracranial extension, this is an important clinical entity.

Alopecia↗
PubMed1992

Variations in the beading configuration in monilethrix.

Using information from a light microscope integrated with a computer, we quantified the variation in node and internode dimensions in monilethrix. We combined this with rate of growth measurements in individual hairs to make the following conclusions. There is considerable variation of node and internode configuration within single hairs. Hairs from the same scalp, sampled at the same time show no mutual coordination of node-internode formation, even when different growth rates are taken into account. There is no apparent correlation between the day-night cycle and the node-internode rhythm. The follicular expression of monilethrix appears largely independent of unifying systemic influences.

Adult↗
PubMed1991

Monilethrix treated with oral retinoids.

We report a childhood case of monilethrix in which oral etretinate was given. Clinically, the cosmetic benefit was marginal. However, of note was that there was an increase in hair length with loss of beading along the shaft of these hairs. The background scalp appearance of keratosis pilaris persisted in these areas. This suggests that the beading alone is influenced by etretinate and is not solely an artefact secondary to the hyperkeratotic condition at the follicular opening.

Administration, Oral↗
PubMed1991

Cyproterone acetate for severe hirsutism: results of a double-blind dose-ranging study.

OBJECTIVE: The objective was to determine if cyproterone acetate (CPA) therapy for hirsute women demonstrated a dose response. DESIGN: A double-blind dose-ranging study of the effect of 3 doses of cyproterone acetate for a period of 12 months. PATIENTS: Twenty-one hirsute women received the Dianette contraceptive pill (35 micrograms ethinyl oestradiol + 2 mg CPA, Schering Healthcare, UK), 20 received Dianette plus 20 mg CPA and 19 received Dianette plus 100 mg CPA: supplementary CPA was administered on days 1-10 of the birth control pill cycle as described by Hammerstein. MEASUREMENTS: Hair growth was measured using the clinical scale of Ferriman and Gallwey and by direct measurement of hair shaft diameter and linear growth of hair on the face, forearm, abdomen and thigh. RESULTS: Thirty-eight women completed 12 months therapy, eight withdrew due to side-effects and 14 were lost to follow-up. All three dose schedules produced significant reductions in clinical hair growth scores. This reduction was seen after 6 months with Dianette alone (P less than 0.005) and after 3 months with both the higher doses (P less than 0.01). There were no significant differences between the effect of different doses at any of the three-monthly time points. Hair diameter measurements were reduced by all doses after 12 months: face by 27*, 37, 37%*, forearm 5, 10, 8%*, abdomen 22*, 39*, 33%*, thigh 12, 24*, 30%* (median reductions (*P less than 0.01) for Dianette, D + 20 mg CPA and D + 100 mg CPA respectively). There were no significant reductions in daily linear growth rates. A comparison of the percentage reduction in hair shaft diameter at each site demonstrated no significant difference between doses, although the reductions by the three doses on the forearm, abdomen and thigh suggested a trend towards a dose response. CONCLUSIONS: We conclude that cyproterone acetate 2 mg daily appears to be as effective as higher doses in the therapy of hirsute women.

Adolescent↗
PubMed1991

The spectrum of malignant melanoma of the nail apparatus.

Unlike most morphological types of malignant melanoma, that of the nail apparatus is relatively rare--only 2% to 3% of one series. Although in the case of blacks and orientals, the incidence of malignant melanoma of the nail apparatus is proportionately more common. However, it is a serious disease with poor 5-year survival figures in the published series--21% to 50%. This poor prognosis may be an intrinsic function of the site and of other parts of the body, but the lateness of diagnosis in many of the published cases is of far more significance. In malignant melanoma at other body sites, late diagnosis usually relates to the patient not presenting early in the course of the disease; this may also apply to nail malignant melanoma. However, the frequency of failure of the first line physician or surgeon to recognize the clinical signs or to perform a biopsy from the correct site to obtain an accurate diagnosis is far more important.

Adult↗
PubMed1990

Hair follicle destruction and regeneration in guinea pig skin after cutaneous freeze injury.

We have investigated the histological changes in hair follicles in guinea pig skin after standardized moderate and severe cryosurgery injuries. Hair follicles were permanently destroyed by cryosurgery, but more than one mechanism may be operative during follicle destruction and shedding. The mechanism depends upon the severity of the freeze. After a light freeze injury, the changes are predominantly within the hair follicle. The hair is shed at the surface and there is selective autolysis of follicular cells, but dermal connective tissue is preserved and there is little surrounding damage. However, after a severe cryoinjury as used in "tumor doses," there is destruction of dermal connective tissue and dermal scarring. The necrotic dermis is shed, taking with it the dead follicles and morphologically normal elastic tissue.

Animals↗
PubMed1990

Tufted folliculitis. A specific bacterial disease?

Residual groups of hair follicles and unusual "tufts" of multiple hairs emerging from single follicular openings have been described in scarring alopecia associated with staphylococcal infection. Various mechanisms have been proposed to explain these findings. Histological study of four cases suggests that retention of telogen hairs through several hair cycles may be responsible for this phenomenon.

Adult↗
PubMed1990

Matting of scalp hair during shampooing--a new look.

We present a new case of irreversible hair matting, a rare, but important and alarming, acquired hair disorder. This case was investigated to test the causal hypothesis proposed in 1984. At the same time four other specimens of matted hair from patients and tangles from normal individuals were also examined. Light and electron microscopy showed dramatic permanent twisting and bending of the hairs through 180 degrees. There was marked variation in the fibre width of hairs from matted samples, with some longitudinally split along a considerable length. This bending and entanglement of hairs of varying widths (felting) seemed to be the main reason for the hairs becoming so dramatically knotted together in four of the cases. In only one case was there any evidence of a viscous fluid binding the hair together. This finding suggests that there may be two different mechanisms involved in hair matting.

Adult↗
PubMed1989

Spironolactone is an effective and well tolerated systemic antiandrogen therapy for Hirsute women.

We treated 22 hirsute women with spironolactone in an open trial to determine whether it caused objective changes in hair growth. Among them, 18 women completed 12 months therapy with 200 mg spironolactone daily. During this period, the mean daily linear growth rates of hair on the face, abdomen, and thigh were reduced to 66% (P less than 0.001), 75% (P less than 0.01), and 72% (P less than 0.001) of their pretreatment values. The mean hair shaft diameters were reduced to 83% (P less than 0.01) on the face, 88% (P less than 0.001) on the arm, 74% (P less than 0.01) on the abdomen, and 80% (P less than 0.001) on the thigh. Daily hair volume production was calculated from the diameter and daily growth rate; it was reduced to 60% (P less than 0.01) on the face, 52% (P less than 0.01) on the arm, 34% (P less than 0.001) on the abdomen, and 48% (P less than 0.001) on the thigh. Six of the 18 women who completed the study developed midcycle vaginal bleeding, and 3 women had previously irregular menstrual cycles regulated. We conclude that spironolactone is effective and well tolerated for hirsute women.

Adult↗