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Biomedical subjects

D A Whiting

Publications and source records attributed to D A Whiting.

At least 37 records · Page 2Linked to original sources
PubMed1993

Diagnostic and predictive value of horizontal sections of scalp biopsy specimens in male pattern androgenetic alopecia.

BACKGROUND: Vertical sections of small scalp biopsy specimens are often inadequate for the diagnosis of male pattern androgenetic alopecia (MPAA). Quantitative analysis of follicular structures in horizontal sections can provide more information. OBJECTIVES: Our purpose was to establish better diagnostic criteria by comparing horizontal and vertical sections of scalp biopsy specimens from MPAA and normal control subjects and to determine the predictive value of horizontal sections, by relating counts of follicular structures in MPAA to subsequent hair regrowth from topical minoxidil therapy. METHODS: Paired 4 mm punch biopsy specimens were taken from 22 normal control subjects and 106 patients with MPAA, for horizontal and vertical sectioning. In horizontal sections, hair bulbs, terminal anagen, catagen and telogen hairs, telogen germinal units, and vellus hairs were counted, as were follicular units and stelae. RESULTS: The diagnosis of MPAA was confirmed by finding decreased terminal hairs and increased stelae and vellus hairs. The average horizontal section contained 22 terminal and 13 vellus hairs, a 1.7:1 ratio. Changes compatible with MPAA were found in most vertical and horizontal sections, but horizontal sections were required for follicular counts and showed terminal:vellus hair ratios diagnostic of MPAA in 67% of cases. Of 44 patients treated with topical minoxidil, five with less than 2 follicular structures/mm2 showed no hair regrowth, 32 with 2 to 4 follicular structures/mm2 showed regrowth in 72%, and seven with more than 4 follicular structures/mm2 showed regrowth in 86% of cases. In MPAA with no significant inflammation, regrowth occurred in 77% of cases, versus 55% in cases with significant inflammation. CONCLUSION: Horizontal sections of scalp biopsy specimens in MPAA provide more diagnostic information than vertical sections and appear to have a predictive value for hair regrowth.

Administration, Cutaneous↗
PubMed1993

Structural requirements for the direct and cytochrome P450-dependent reaction of cyclic alpha,beta-unsaturated carbonyl compounds with glutathione: a study with coumarin and related compounds.

The interaction of glutathione (GSH) with coumarin, or one of a series of compounds related to coumarin, was assessed in the absence and presence of liver microsomes (direct reaction and indirect reaction, respectively) to determine the structural requirements for direct and mono-oxygenase-mediated reaction of cyclic alpha,beta-unsaturated carbonyls with GSH. Acrolein was used as a positive control for the direct reaction, and produced complete or nearly complete depletion of GSH under all assay conditions. 5,6-Dihydro-2H-pyran-2-one and 2-cyclohexen-1-one also produced substantial depletion of GSH in the direct reaction, which was not increased by the addition of liver microsomes. Coumarin, 2H-pyran-2-one and precocene I (a substituted pyran lacking the 2-one structure) were not substrates for the direct reaction but did cause depletion of GSH when incubated in the presence of rat or human liver microsomes. These depletions were dependent on a functioning mono-oxygenase system as judged by the effects of omission of cofactors, addition of competitive or inactivating inhibitors of cytochrome P450, and induction. Dihydrocoumarin, delta-valerolactone, cyclohexanone and 4H-pyran-4-one were not substrates for either the direct or indirect reaction. These findings are rationalized on the basis of a direct nucleophilic attack of GSH on the alpha,beta-centre of the alpha,beta-unsaturated carbonyl compounds, which is hindered by benzenoid resonance in coumarin and 2H-pyran-2-one, for which enzyme-mediated reaction with GSH, probably via a 3,4-epoxide, is the favoured mechanism.

Aged↗
PubMed1992

Treatment of female androgenetic alopecia with minoxidil 2%.

The safety and efficacy of minoxidil 2% for the treatment of female androgenetic alopecia was assessed in a 32-week double-blind placebo-controlled trial. Thirty-three women aged 22 to 44 years with hair loss classified as Ludwig's grade I or II were enrolled, and 28 completed the trial. Before the administration of treatment, mean nonvellus hair counts were taken within a 1-cm2 target area of the scalp. For the 15 patients in the minoxidil group, the mean count was 169 hairs compared with 161 hairs for the 13 patients in the placebo group. At the completion of the trial, the patients treated with minoxidil 2% had a mean nonvellus hair count of 195 hairs versus a mean hair count of 177 for patients in the placebo group; 60% (9) of the patients in the minoxidil group showed minimal to moderate hair growth compared with 46% (6) of the patients in the placebo group. No serious side effects were encountered during this study, nor any significant changes in safety parameters. There were no dropouts due to medical events related to minoxidil 2%.

Administration, Topical↗
PubMed1992

Bubble hair.

An unusual hair dystrophy was studied by means of light and electron microscopy. Hair fibers demonstrated a boomerang deformity containing small and large "bubbles". Electron microscopy revealed a loss of cortical cells and medulla at these sites. Cross-section images showed either a single large cavity or a reticulated, "swiss cheese-like" loss of cells. These two cases represent the second and third reported cases of bubble hair deformity. We present the second light and electron microscopic study of this disorder, including new electron microscopic findings. The cause of bubble hair deformity remains obscure. The involved tufts of wiry hair resolved with gentle hair care. This suggests that trauma to the hair shaft may play a role. It is likely that additional cases of bubble hair remain unrecognized. Investigation of other patients with localized tufts of wiry hair is likely to reveal additional cases.

Adult↗
PubMed1992

Treatment of cutaneous squamous cell carcinomas by intralesional interferon alfa-2b therapy.

BACKGROUND AND DESIGN: Intralesional recombinant interferon alfa-2b has been shown to be effective in the treatment of actinic keratoses and basal cell carcinomas. This open-label study was designed to evaluate the effectiveness and cosmetic result of this therapy on actinically induced, primary cutaneous squamous cell carcinomas. Thirty-six squamous cell carcinomas (28 invasive lesions and 8 in situ lesions) ranging in size from 0.5 to 2.0 cm in the longest dimension were treated with interferon alfa-2b 1.5 million units injected intralesionally three times per week for 3 weeks. Eighteen weeks following therapy, the treatment sites were excised and examined for histologic evidence of remaining tumor. RESULTS: Thirty-three (97.1%) of 34 evaluable lesions revealed an absence of squamous cell carcinoma histologically after therapy, although three biopsy specimens (8.8%) obtained after treatment showed actinic keratoses, for an overall complete response rate of 88.2%. The lesion not eliminated after treatment was an invasive squamous cell carcinoma. The investigators and patients independently judged 93.9% of cases to have a very good or excellent cosmetic result. Adverse reactions were limited to those influenzalike symptoms well recognized to occur with interferon therapy and these were well tolerated. Only one patient discontinued therapy due to side effects. CONCLUSIONS: This trial demonstrates that intralesional interferon is effective in the treatment of small sun-induced squamous cell carcinomas with well-tolerated side effects and a highly acceptable cosmetic result.

Adult↗
PubMed1991

O-hydroxyphenylacetaldehyde: a major novel metabolite of coumarin formed by rat, gerbil and human liver microsomes.

A major novel coumarin metabolite was isolated from rat hepatic microsomal incubations by high-performance liquid chromatography. In the presence of a rat liver cytosolic fraction and NADH it was rapidly metabolized to O-hydroxyphenylethanol. The metabolite co-chromatographed with an authentic sample of O-hydroxyphenylacetaldehyde and its identity was confirmed by mass spectral analysis. The formation of O-hydroxyphenylacetaldehyde from coumarin was NADPH-dependent. It was the major metabolite formed by rat, gerbil and human liver microsomes at a coumarin concentration of 1mM.

Acetaldehyde↗
PubMed1987

Structural abnormalities of the hair shaft.

Abnormalities of the hair shaft are varied and often confusing. They do require accurate recognition, which can be helpful in the diagnosis and management of a hair disorder, or in the detection of underlying disease. A reliable evaluation of hair shaft abnormality is dependent on familiarity with the vast structural variations in normal hair, the hair growth cycle, and the changes produced by weathering. These structural abnormalities can be congenital or acquired, and some are associated with hair fragility. The classification used here has the advantage of simplicity and is keyed to easy recognition of the abnormalities under the light microscope. The four major types of abnormality are fractures, irregularities, twisting, and extraneous matter affecting the hair shaft. The diagnostic features of the different hair shaft abnormalities are outlined.

Corynebacterium Infections↗
PubMed1987

The treatment of alopecia areata.

Alopecia areata has an unpredictable course that is not easily altered by treatment. Different treatments will provoke regrowth of terminal hair to a variable extent but may not prevent further hair loss. Corticosteroids are the most popular form of treatment and can be given topically, intralesionally, or, in rare cases, systemically; they work best by intralesional injection of long-acting steroid suspensions. Minoxidil has had limited success in stimulating hair regrowth without altering the course of alopecia areata. Short-contact anthralin therapy has also showed promise, especially in children. Other forms of treatment described herein include contact sensitizers, phototherapy, and immunomodulators such as inosiplex, cyclosporine, and nitrogen mustard.

Alopecia Areata↗
PubMed1984

Resistant childhood psoriasis: an analysis of patients seen in a day-care center.

During a three-and-one-half-year period, 54 children aged 1 to 16 years, all of whom had resistant psoriasis, were seen at a day-care center. The female: male ratio was 3:2. In 74% of the patients, the onset of psoriasis occurred when they were below 10 years of age. Papules and plaques occurred in 78% of cases, guttate lesions in 16%, and nail involvement in 21%. A family history of psoriasis was present in 69% of cases, preceding upper respiratory tract infections occurred in 35%, and prior cradle cap and/or diaper rash in 50%. In the day-care center, Goeckerman therapy was given to 31 children. The average duration of treatment was 12 days, producing maximum clearing of over 90% in 64% of patients, with substantial improvement in the remainder. After three months, the psoriasis in 83% of these patients was over 90% clear; 43% showed maximum clearing at one year. Two patients were treated with anthralin and ultraviolet light alone, one with good results. One patient with nail psoriasis alone was not treated. The remaining 20 patients were either unable to attend for treatment at the center or had less extensive psoriasis. Home treatment was prescribed for them, with less satisfactory results.

Administration, Topical↗
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↗
PubMed1979

Acne.

The cause of acne is still obscure, but genetic predisposition, sebaceous overactivity, overgrowth of bacterial flora and exposure to comedogenic substances are all significant factors. Acne lesions occur mainly in sebaceous follicles, which are characterized by deep follicular canals and large sebaceous glands. The associated seborrhea is not due to a circulatory excess of androgens but may be caused by a local amplification of androgenic activity. This, in turn, may be due to large numbers of androgen receptors and a high concentration of enzymes such as 17beta-hydroxysteroid dehydrogenase, within the sebaceous gland itself. Hyperkeratosis of the retention type in the pilary infrainfundibulum obstructs the outflow of sebum and keratin flakes. This favors the proliferation of Propionibacterium acnes which may initiate inflammation in microcomedos and lead to formation of pustules, papules or nodules. Topical therapy with tretinoin, benzoyl peroxide and antibiotics such as clindamycin is widely used today. Oral tetracyclines and other chemotherapeutic agents remain necessary in severe cases.

Acne Vulgaris↗
PubMed1978

Skin tumours in white South Africans. Part IV. Influence of occupation, sun sensitivity, colouring and associated skin tumours on the incidence of skin tumours.

Outdoor and industrial occupations in the southern Transvaal do not increase the incidence of any skin tumour excepting that of squamous cell carcinoma. However, they accelerate the onset of solar keratoses and squamous and basal cell carcinomas. A fair, sun-sensitive skin, red hair and blue eyes are more important factors predisposing towards the development of skin cancer. Unduly large numbers of seborrhoeic keratoses were found in association with polyps, and of intradermal naevi with both cavernous haemangiomas and lentigines. A high proportion of solar keratosis was found in both squamous cell carcinoma and Bowen's disease, and of basal cell carcinoma in superficial basal carcinoma, but the reverse associations were not significant.

Humans↗
PubMed1978

Skin tumours in white South Africans. Part V. Treatment of skin tumours.

Dermatological methods of treating skin tumours, comprising curettage and electrodesiccation, simple excision and topical 5-fluoro-uracil, are described. Treatment of benign tumours was successful and recurrences were insignificant. Most skin cancers were treated by curettage and electrodesiccation. Cure rates with this method were 96.5% for basal cell, 94.2% for squamous cell and 100% for superficial carcinomas. Cosmetic results were satisfactory in 95% of cases. The indications for the different methods of treating skin tumours are discussed. It is concluded that curettage and electrodesiccation, in experienced hands, is a quick, effective and inexpensive procedure suitable for treating most of the skin tumours encountered in dermatological practice.

Basal Cell Carcinoma↗
PubMed1978

Skin tumours in White South Africans. Part II. Age and sex distribution.

The incidence of skin tumours according to age and sex is analysed. Sun-induced tumours occur most commonly in persons between the ages of 50 and 69 years. One half of malignant melanomas are seen at ages following the decline in incidence of junctional and compound naevi. Squamous cell carcinomas occur earlier in males. Histiocytomas are seen earlier and spider angiomas later in females. Tumours occurring predominantly in males include squamous and basal cell carcinoma, kerato-acanthoma and pyogenic granuloma. Histiocytoma and spider angioma are seen more often in females.

Adolescent↗
PubMed1978

Skin tumours in White South Africans. Part III. Distribution of skin tumours on the body.

The distribution of the commoner skin tumours is detailed according to body site. Cutaneous horns, keratoacanthomas, Bowen's lesions and squamous and basal cell carcinomas occur mainly on exposed areas, confirming the importance of sunlight in their causation. However, a quarter of the Bowen's and over half the superficial basal cell carcinoma lesions are seen on covered areas, indicating that these tumours are both distinct entities. That seborrhoeic keratoses, intradermal and compound naevi, haemangiomas and lentigines were most often seen on the face may simply reflect the fact that patients often seek cosmetic help for these complaints. Distributional analysis suggests that cellular naevi on the trunk are much more likely to cause malignant melanoma than those on exposed areas.

Basal Cell Carcinoma↗
PubMed1978

Skin tumours in White South Africans. Part I. Patients, methods and incidence.

A survey of all skin tumours recorded in Whites in a dermatological practice in the southern Transvaal is presented. Nearly a quarter of the 15 000 consecutive patients seen over a period of 7 years complained of skin tumours. They were considered to be a representative sample of the population, since their occupations compared well with those of White South Africans in general. The relative frequency of skin tumours is shown in detail. Sun-induced tumours are common, solar keratoses occurring in 10% of all patients, basal cell carcinomas in 4%, kerato-acanthomas in 1% and squamous cell carcinomas in 0,5%. Seborrhoeic keratoses, cellular naevi, polyps, cysts, angiomas and histiocytomas are also commonly seen; patients with these complaints often seek medical advice for cosmetic reasons.

Basal Cell Carcinoma↗