A Bayesian analysis of colonic crypt structure and coordinated response to carcinogen exposure incorporating missing crypts.

This paper is concerned with modeling the architecture of colonic crypts and the implications of this modeling for understanding possible coordinated response of carcinogen-induced DNA damage between various regions of the colon. The methods we develop to address these two issues are applied to a particular important example in colon carcinogenesis. We cast the problem as an unusual and not previously studied hierarchical mixed-effects model characterized by completely missing covariates in units at a structurally base level, except for some randomly selected units.

Fish oil enhances targeted apoptosis during colon tumor initiation in part by downregulating Bcl-2.

We have shown that fish oil is protective against colon tumorigenesis, primarily by upregulating apoptosis. Production of prostaglandin E2 (PGE2) in colon cancer cells by cyclooxygenase (COX)-I and -II is known to inhibit apoptosis by induction of bcl-2. Because we have shown that fish oil downregulates PGE2 and COX-II, we hypothesized that this upregulation of apoptosis would be coincident with a downregulation of bcl-2.

Dietary fish oil reduces oxidative DNA damage in rat colonocytes.

Prolonged generation of reactive oxygen species by inflammatory mediators can induce oxidative DNA damage (8-oxodG formation), potentially resulting in intestinal tumorigenesis. Fish oil (FO), compared to corn oil (CO), has been shown to downregulate inflammation and upregulate apoptosis targeted at damaged cells. We hypothesized FO could protect the intestine against 8-oxodG formation during dextran sodium sulfate- (DSS-) induced inflammation.

Lasers in dermatology: four decades of progress.

Advances in laser technology have progressed so rapidly during the past decade that successful treatment of many cutaneous concerns and congenital defects, including vascular and pigmented lesions, tattoos, scars, and unwanted hair-can be achieved. The demand for laser surgery has increased substantially by patients and dermatologists alike as a result of the relative ease with which many of these lesions can be removed, combined with a low incidence of adverse postoperative sequelae. Refinements in laser technology and technique have provided patients and practitioners with more therapeutic choices and improved clinical results.

Botulinum toxin type B for dynamic glabellar rhytides refractory to botulinum toxin type A.

Background: Botulinum toxin type B (BTX-B; Myobloc) has recently been introduced for the treatment of dynamic rhytides. This serotype is structurally similar to botulinum toxin type A (BTX-A; Botox) and appears to produce equivalent muscular paralysis. Because of the fact that some patients may become resistant to the effects of BTX-A with its continued use or may require large doses of type A to exert adequate muscular paralysis, the use of BTX-B may prove beneficial in these cases.

Magmatic events can produce rapid changes in hydrothermal vent chemistry.

The Endeavour segment of the Juan de Fuca ridge is host to one of the most vigorous hydrothermal areas found on the global mid-ocean-ridge system, with five separate vent fields located within 15 km along the top of the ridge segment. Over the past decade, the largest of these vent fields, the 'Main Endeavour Field', has exhibited a constant spatial gradient in temperature and chloride concentration in its vent fluids, apparently driven by differences in the nature and extent of subsurface phase separation. This stable situation was disturbed on 8 June 1999 by an earthquake swarm.

Quantification of human intestinal gene expression profiles using exfoliated colonocytes: a pilot study.

Early detection of colon cancer can result in a high cure rate; therefore, an accurate screening method is imperative. Adoption of non-invasive testing designed to reduce anxiety over colorectal cancer screening and improve early detection is highly desirable. Therefore, we have developed a novel non-invasive methodology utilizing exfoliated colonocytes in order to quantify colonic messenger RNAs (mRNAs).

Are all infrared lasers equally effective in skin rejuvenation.

In an attempt to limit the prolonged postoperative healing associated with ablative laser skin resurfacing and in response to growing public interest in less invasive treatment modalities, nonablative laser and light source technology was developed. Over the past few years, several clinical and histologic research studies have been conducted to determine the relative efficacy of these nonablative systems. These systems stimulate dermal collagen remodeling using wavelengths and concomitant tissue cooling that limit injury to the epidermis, thereby minimizing or eliminating postoperative sequelae.

Evaluation of a novel topical anesthetic agent for cutaneous laser resurfacing: a randomized comparison study.

Background: A variety of topical anesthetic compounds are available for use prior to minimally or moderately painful cutaneous laser procedures. A novel lidocaine/tetracaine-based peel has recently been developed that is applied to the skin as a cream and, once air dried, is removed as a flexible film that may prove useful in providing adequate dermal anesthesia for dermatologic laser surgery.

Objective: To evaluate the clinical efficacy of a novel topical anesthetic peel preparation for induction of local anesthesia prior to full-face cutaneous laser resurfacing.

Fish oil increases mitochondrial phospholipid unsaturation, upregulating reactive oxygen species and apoptosis in rat colonocytes.

We have shown that a combination of fish oil (high in n-3 fatty acids) with the butyrate-producing fiber pectin, upregulates apoptosis in colon cells exposed to the carcinogen azoxymethane, protecting against colon tumor development. We now hypothesize that n-3 fatty acids prime the colonocytes such that butyrate can initiate apoptosis. To test this, 30 Sprague-Dawley rats were provided with diets differing in the fatty acid composition (corn oil, fish oil or a purified fatty acid ethyl ester diet).

Intrinsic room-temperature electrophosphorescence from a pi-conjugated polymer.

Electrically induced phosphorescence from a poly(para-phenylene) ladder-type polymer is observed for the first time and characterized using time resolved spectroscopy. Short-lived phosphorescence is also observed in gated fluorescence spectra and is found to be quenched reversibly by oxygen. Thermally activated triplet diffusion to covalently bound palladium sites, which are formed at a concentration of about 80 ppm in a side reaction during polymer synthesis, is believed to be the cause of this novel effect, which suggests a new approach to the design of efficient electroluminescent materials.

Opportunities for nutritional amelioration of radiation-induced cellular damage.

The closed environment and limited evasive capabilities inherent in space flight cause astronauts to be exposed to many potential harmful agents (chemical contaminants in the environment and cosmic radiation exposure). Current power systems used to achieve space flight are prohibitively expensive for supporting the weight requirements to fully shield astronauts from cosmic radiation. Therefore, radiation poses a major, currently unresolvable risk for astronauts, especially for long-duration space flights.

Nonablative laser skin resurfacing using a 1540 nm erbium glass laser: a clinical and histologic analysis.

Background: A variety of laser systems have recently become available that allow for selective dermal remodeling without disruption of the epidermal surface. Modest clinical improvement in mild to moderate photoinduced facial rhytides with minimal morbidity is typical of these nonablative lasers, providing a significant advantage over traditional ablative laser systems.

Objective: To determine the clinical and histologic effects of a novel 1540 nm erbium glass laser on facial rhytides.

Oncogenic ras alters sensitivity of mouse colonocytes to butyrate and fatty acid mediated growth arrest and apoptosis.

Docosahexaenoic acid (DHA) and butyrate favorably modulate colonocyte proliferation and apoptosis. In order to elucidate how oncogenic Ras modulates responses to these chemopreventive nutrients, we incubated isogenic non-transformed and Ras malignant transformed mouse colon cells with butyrate and DHA or linoleic acid (LA). Combining DHA with 1mM butyrate decreased proliferation relative to LA or no PUFA treatment in both cell lines.

Clinical comparison of sclerotherapy versus long-pulsed Nd:YAG laser treatment for lower extremity telangiectases.

Background: Sclerotherapy has traditionally been considered the gold standard of treatment for leg veins, but patient fear of multiple needle injections and side effects of treatment have fueled investigation into other treatment alternatives. As a result, vascular-specific laser and light sources have been developed in an effort to treat these vessels with minimal morbidity and improved efficacy.

Objective: To compare the clinical efficacy of leg telangiectasia treatment with sodium tetradecyl sulfate sclerotherapy to long-pulsed 1064 nm Nd:YAG laser irradiation.

Dietary n-3 PUFA alter colonocyte mitochondrial membrane composition and function.

There is experimental evidence that dietary fish oil, which contains the n-3 fatty acid family, i.e., EPA and DHA, protects against colon tumor development, in part by increasing apoptosis.

Laser scar revision.

A variety of lasers can be used to treat scars and striae effectively. It is of paramount importance that the type of scar be properly classified on initial examination so that the most appropriate method of treatment can be chosen. Classification also allows the laser surgeon to discuss with the patient the anticipated response to treatment.

Regional anesthesia with monitored anesthesia care for dermatologic laser surgery.

This article describes an anesthetic technique that the authors have found useful for cutaneous laser surgery in keeping with the standards for office-based anesthesia practice. Although still in its infancy, office-based anesthesia for dermatologic laser procedures has become one of the most challenging yet rewarding fields of anesthesia today. As laser procedures continue to flourish, with seemingly endless technologic advances, surgeons, anesthesia providers, and other medical personnel must work collaboratively in developing appropriate office-based practice.

Laser resurfacing of darkly pigmented patients.

Hyperpigmentation following laser resurfacing in darker-skinned individuals is common but treatable. This pigmentation is usually heralded by persistent erythema and can be prevented in most patients if aggressive laser resurfacing is curtailed and conservative or single-pass techniques are applied. Avoiding excessive intraoperative frictional trauma when removing the desiccated tissue Avoiding excessive intraoperative frictional trauma when removing the desiccated tissue and potentially irritating agents or infections in the pre- or postoperative period is also instrumental in avoiding long-term complications.

Cutaneous metastasis from an intracranial glioblastoma multiforme.

A 34-year-old white man with a history of an intracranial glioblastoma multiforme was treated with surgical excision and radiotherapy. Five months later, the patient had a rapidly growing scalp mass develop. This lesion was excised, and the histology revealed a tumor that was similar to the originally resected intracranial glioblastoma.

Lasers in dermatology. An overview of types and indications.

Advances in laser technology have been so marked over the past two decades that successful eradication of many cutaneous pathologies and congenital defects, including vascular and pigmented lesions, tattoos, scars, and unwanted hair, can now be fully realized. Because of the relative ease with which many of these lesions can be removed, coupled with a low incidence of adverse postoperative sequelae, demand for laser surgery has increased substantially. In this review, the currently available laser systems with cutaneous application are outlined, with special reference to recent advancements and modifications in laser technology that have greatly expanded the laser surgeon's armamentarium and improved upon overall treatment efficacy.

Anatomical site-specific response to DNA damage is related to later tumor development in the rat azoxymethane colon carcinogenesis model.

There is now general agreement that the etiology of proximal and distal colon cancers may differ, thus prompting renewed interest in understanding anatomical site-specific molecular mechanisms of tumor development. Using a 2x2x2 factorial design with male Sprague-Dawley rats (corn oil, fish oil; pectin, cellulose; plus or minus azoxymethane injection) we found a greater than 2-fold difference (P < 0.001) in tumor incidence proximally versus distally (prox/dist ratio: corn oil, 2.