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Biomedical subjects

N Levine

Publications and source records attributed to N Levine.

At least 19 recordsLinked to original sources
PubMed1992

Tretinoin emollient cream: a new therapy for photodamaged skin.

BACKGROUND: Tretinoin administered topically in 0.1% concentration has been shown to improve the wrinkling and irregular pigmentation of photoaged skin. OBJECTIVE: The purpose of this study was to assess the safety and efficacy of various concentrations of tretinoin in a new emollient cream base in the treatment of photoaged skin. METHODS: Three concentrations of tretinoin (0.05%, 0.01%, and 0.001%) in a new emollient cream formulation were compared with vehicle in a 24-week, double-blind, randomized, multicenter study of 296 subjects with photodamaged facial skin. RESULTS: Tretinoin emollient cream 0.05% gave a significantly better global response to therapy than vehicle (p less than 0.001), with 68% of subjects exhibiting improvement at the end of therapy, compared with 43% of subjects in the vehicle group. An excellent or good response was found in 26% of subjects treated with tretinoin emollient cream 0.05% versus 11% of vehicle-treated subjects. Fine wrinkling, mottled hyperpigmentation, and roughness were more improved in subjects who received tretinoin emollient cream 0.05% than in vehicle-treated subjects (p less than 0.05). No significant difference was found between vehicle and tretinoin emollient cream 0.01% or 0.001%. Histologic examination showed increases in epidermal and granular layer thickness, decreased melanin content and compaction of the stratum corneum after therapy with tretinoin emollient cream 0.05% or 0.01%. Mild to moderate skin reactions, such as erythema, peeling, and burning, were the most common side effects and, although most prevalent in the group using the 0.05% concentration, generally did not limit tretinoin use. CONCLUSION: Tretinoin emollient cream 0.05% appears to be safe and effective in the treatment of photodamaged skin.

Administration, Topical↗
PubMed1992

Effects of a melanotropic peptide on melanoma cell growth, metastasis, and invasion.

Melanocyte stimulating hormone (alpha-MSH, alpha-melanotropin),Ac-Ser-Tyr-Ser-Met-Glu-His-Phe-Arg-Trp-Gly-Ly-Pro-Va l-NH2, regulates melanogenesis within epidermal melanocytes of many animals. An MSH analogue ([Nle4,D-Phe7]alpha-MSH) that exhibits superpotency and prolonged biological activity has been synthesized, biologically characterized, and is presently in clinical trials to determine its possible clinical use in tanning of the skin. It also has potential for the diagnosis, localization, and chemotherapy of melanoma. The effects of this analogue on the growth, metastatic behavior, and invasive potential of a melanotic variant of Cloudman S-91 murine melanoma are reported here. In an intracutaneous murine model of melanoma cell tumor growth, the analogue did not increase primary tumor growth (size) after the period of administration of the peptide hormone analogue and did not affect spontaneous lung metastases. Survival times for the control and melanotropin-treated groups were similar, suggesting that overall tumor burden was not affected by treatment with the hormone analogue. Last, melanoma cell invasion through a human amniotic basement membrane in vitro was not enhanced compared to untreated cells.

Amino Acid Sequence↗
PubMed1992

Advances in the treatment of acquired and developmental defects of hard dental tissues.

With the decline in dental caries, the dental profession and the general public have become sensitized to the "new" specialty of cosmetic dentistry. As a consequence, research in the field of dental materials for the ideal, most natural restorative materials and techniques has become a primary focus and has had a profound influence on dental education and practice. This brief article will highlight some of these newer concepts.

Composite Resins↗
PubMed1992

Controlled localized heat therapy in cutaneous warts.

BACKGROUND: Controlled localized heating as a method of superficial tissue destruction has been used in veterinary medicine for the treatment of benign and malignant tumors. The rationale for its use is that the diseased tissue being treated is more sensitive to the effects of heating than is normal tissue. This technology was applied to the treatment of common hand warts in a placebo-controlled study. OBSERVATIONS: Twenty-nine warts were treated one to four times (median, two times) at 50 degrees C for 30 to 60 seconds. Twenty-five (86%) of 29 treated verrucae regressed completely while seven (41%) of 17 control warts resolved during the course of the study. No wart that regressed regrew during the follow-up period (mean, 15.6 weeks). CONCLUSIONS: Controlled localized heating can cause the regression of hand warts. The 86% regression rate compares favorably with other wart treatment modalities. The mechanism of action and the effect of heat on these virally induced tumors is not known but may involve direct antiviral effects, physical destruction of the tumor, or the promotion of an inflammatory response that ultimately eradicates the lesion.

Adult↗
PubMed1991

Induction of skin tanning by subcutaneous administration of a potent synthetic melanotropin.

UNLABELLED: OBJECTIVE--To determine the efficacy of short-term administration of a synthetic analogue of alpha-melanotropin, [Nle4D-Phe7] (NDP)-alpha-melanocyte-stimulating hormone (MSH), in darkening (tanning) human skin. DESIGN--Randomized, placebo-controlled, double-blind clinical trial. SETTING--Clinical research unit of a university medical center. SUBJECTS--Twenty-eight healthy white men with a history of either poor tanning (skin type I or II) or good tanning (skin type III or IV) recruited from advertisements and paid to participate in the study. METHODS--Each subject received 10 subcutaneous injections of either a purified NDP preparation or saline over 12 days. They were followed up for 7 weeks after therapy was completed. All subjects used a high-potency sunscreen during the trial. MAIN OUTCOME MEASURE--Skin darkening was quantified by serial chromaticity measurements prior to, during, and after therapy. RESULTS: -A significant parabolic curve of skin darkening activity was noted in subjects with skin type I or II (P less than .001) and with skin type III or IV (P much less than .001) who were given NDP. No darkening occurred in the subjects who were given a placebo. Peak changes were seen 1 to 3 weeks after therapy was completed. CONCLUSION--Human skin darkens as a response to a synthetic melanotropin given by subcutaneous injection. Skin tanning appears possible without potentially harmful exposure to ultraviolet radiation.

Adult↗
PubMed1979

Operative blood loss in transurethral prostatectomy.

Operative blood loss was measured in 62 transurethral prostatectomies performed with a continuous irrigation suction resectoscope. Although blood loss per minute is comparable to levels in earlier studies the rapidity with which resection can be accomplished results in a marked reduction in operative blood loss.

Aged↗
PubMed1979

Localized pemphigoid simulating dyshidrosiform dermatitis.

A patient had a localized, persistent vesicular eruption of the feet that was clinically identical to dyshidrosiform dermatitis. Direct and indirect immunofluorescent studies revealed a bullous pemphigoid (BP) pattern. Antibody blocking experiments showed the patient's circulating basement membrane zone antibody to be identical to that of classical BP. Possible pathogenetic mechanisms of localized BP are discussed.

Aged↗
PubMed1978

Measurement of pH in the rat epididymis in vivo.

Antimony microelectrodes were used to measure pH in rat seminiferous tubules and epididymides in vivo. Acidification of fluid leaving the testis occurs primarily in the initial segment and to a lesser extent in the intermediate zone.

Animals↗