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Biomedical subjects

L Dzubow

Publications and source records attributed to L Dzubow.

11 recordsLinked to original sources
PubMed1996

Treatment of photodamaged skin with trichloroacetic acid and topical tretinoin.

BACKGROUND: Photodamaged skin typically displays lentigines, actinic keratoses, wrinkles, and textural alteration. Chemical peeling has been used to treat these, but few controlled studies have been performed to determine its efficacy. OBJECTIVE: Our purpose was to compare the efficacy of a medium-depth chemical peel with and without tretinoin before and after treatment. METHODS: Sixteen men with actinic damage including actinic keratoses were treated with a 40% trichloroacetic acid(TCA) chemical peel. Half were pretreated for 6 weeks with topical tretinoin; they also used tretinoin after the peel. Photographs were obtained at baseline and at 6 weeks and 6 months after treatment. Changes in specific features were rated by a panel of three examiners. RESULTS: Some improvement was noted in all patients. More rapid and even frosting was observed in the patients pretreated with tretinoin. Solar lentigines, actinic keratoses, and skin texture were the features of photoaging most affected; wrinkles were least affected. No statistically significant difference was found between patients treated with TCA and tretinoin (before and after peel) and those with TCA alone. CONCLUSION: A medium-depth chemical peel with 40% TCA alone produced moderate improvement in some manifestations of actinic damage but had little effect on wrinkles. Treatment with tretinoin before and after TCA did not significantly enhance the efficacy of the peel.

Administration, Cutaneous↗
PubMed1995

The isolated frontal forelock.

BACKGROUND: The progression and extent of male pattern baldness is statistically unpredictable. OBJECTIVE: An approach to the patient with male pattern baldness is suggested, which results in a product that changes appearance in a positive way, is natural, requires no maintenance, and does not deconstruct with progression of alopecia. METHODS AND RESULTS: A technique is described for transplantation of the frontal forelock allowing creation of a soft anterior zone and a dense posterior component. CONCLUSION: The utilization of donor hair to create a transplanted forelock will eventuate in a product that maintains naturalness regardless of the progression or extent of future hair loss.

Adult↗
PubMed1993

Mouse skin is particularly susceptible to tumor initiation during early anagen of the hair cycle: possible involvement of hair follicle stem cells.

Stem cells are believed to be a necessary target of chemical carcinogens. Based on autoradiographic, ultrastructural, and biologic criteria, we have recently proposed that hair follicle stem cells reside not in the bulb, but in the upper outer root sheath in an area called the bulge. Proliferating cells have been shown to be more susceptible to tumor initiation, and we have recently demonstrated that cells in the bulge undergo transient proliferation during early anagen. Therefore, we theorized that mouse skin should be particularly susceptible to carcinogen application during early anagen phase. In this paper, we show that early anagen Swiss and Sencar mouse skin is indeed particularly susceptible to one- and two-stage chemical carcinogenesis, resulting in tumor yields one to five times those obtained with telogen-timed carcinogen application. Our findings implicate a possible involvement of the bulge cells as precursors to some of the skin cancers, and support the concept that these are stem cells. These observations also raise important questions about the cellular origins and biologic behavior of chemically induced murine skin tumors.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1988

Activation of human squamous cell carcinoma ornithine decarboxylase activity by guanosine triphosphate.

Previous studies have demonstrated the presence in mouse epidermal tumors of a structurally and functionally altered ornithine decarboxylase (ODC). In this report, the enzymatic properties of ODC from normal human skin and squamous cell carcinomas are examined. Some tumors contained a more heat stable ODC than the enzyme found in normal skin. GTP stimulated enzyme activity in four of seven tumor extracts tested but had no effect on normal skin ODC. Kinetic analyses indicated that GTP either lowered the apparent Km of tumor ODC for L-ornithine, increased the Vmax, or had both effects, depending on the tumor examined. Gel filtration chromatography of crude tumor extracts indicated the existence of multiple molecular weight forms of ODC, some of which can be activated by GTP and some of which are unaffected by GTP. Some tumors contain both a GTP-activatable and -nonactivatable form of the enzyme. Immunolocalization studies demonstrated the presence within squamous cell carcinomas of cells with a constitutively high level of immunoreactive ODC, a situation never observed in normal skin tissue. These results suggest that some human squamous cell carcinomas contain a functionally altered ODC that may be aberrantly regulated.

Carcinoma, Squamous Cell↗
PubMed1975

Computer simulation of the metabolism of guinea pig brain slices, and how they differ from the intact brain.

A computer model of the metabolism of glutamate, glutamine, gamma-aminobutyrate and the Krebs cycle in guinea pig cortex slices has been constructed in terms of 98 reactions among 38 unlabeled species. Fitting the data from slices required the addition of a third small compartment to previous 2-compartment models based on whole brain experiments. This third compartment corresponds to the tissue damaged during the slicing process, and dominates the metabolism of 14C-labeled substrates at early times. The times required for equilibration between this additional compartment and the bulk of the slice are no longer than expected. Interpretation of short-term slice experiments may be subject to appreciable error owing to the presence of this additional compartment.

Acetates↗