Assay of gamma-glutamylcysteine synthetase activity in Plasmodium berghei by liquid chromatography with electrochemical detection.

This work describes a high-performance liquid chromatography (HPLC) method to determine gamma-glutamylcysteine (gamma-GC), the intermediate product of glutathione biosynthesis. Separation relies on isocratic reversed-phase chromatography using a Symmetry C18 HPLC column, particle size 5 microm, 4.6 x 250 mm i.d. The mobile phase is methanol-dibasic sodium phosphate (pH 6.6; 2.8 mM) (10:90, v/v) at the flow-rate of 0.5 ml/min and detection is operated electrochemically (+200 and +550 mV) with a pre-column derivatisation reaction using ortho-phthalaldehyde (OPA) as reagent. Under these conditions the calibration range of gamma-GC was 0.3-10 microg/ml; the limit of quantification was 0.3 microg/ml; accuracy, expressed as %Bias, was <10 and precision (%CV) was <6. The proposed HPLC assay was used to quantitate the gamma-glutamylcysteine produced by the gamma-glutamylcysteine synthetase of the rodent malaria parasite Plasmodium berghei in an in vitro enzymatic assay.

Epidermal nevus syndrome: a review and case report.

The epidermal nevus syndrome is a disease complex of epidermal nevi and developmental abnormalities of different organ systems. The authors present a case of congenital systematized epidermal nevus syndrome in a patient with skin lesions covering approximately 80% of the total body surface area. The patient underwent staged treatment of the epidermal nevi with a carbon dioxide laser utilizing two different techniques. The larger verrucous lesions were debulked initially, and the resulting defects and thinner lesions were treated using the Silk Touch modality. The lesions were dermaplaned sequentially until they were ablated completely. All wounds healed without complication, and in a 2-year follow-up the patient has experienced no recurrence in the treated areas. Epidermal nevi can be treated safely, effectively, and without recurrence with carbon dioxide laser ablation.

Endoscopic-assisted carpal tunnel release: a coupling of endoscopic and open techniques.

Endoscopic-assisted carpal tunnel release (CTR) is a blending of the techniques of the open and endoscopic methods of carpal tunnel release. Endoscopic-assisted CTR increases visualization and safety over commonly performed endoscopic techniques while retaining the advantage of a smaller, more distally located scar and less dissection.

Recycling unused medical supplies: a surgeon's response.

In Third World countries, there is a desperate need for basic medical supplies. Surgeons are responsible for a significant amount of medical waste in operating rooms, and much of that waste comes from partially used prepackaged sterile operative sets. In October 1992, InterVol established a regional pilot program in Rochester, N.Y., to test the feasibility of collecting unused medical supplies from area health-care facilities and shipping them to countries that need them. This project was designed to help hospitals dispose of reusable medical supplies while providing direct support to Third World hospitals and to medical teams that volunteer in Third World countries. In the process, a data base was created, which could be analyzed to find new ways of limiting unused materials that needed to be discarded. This project operated in four phases: (1) setup and education, (2) collection, (3) sorting and inventory, and (4) distribution. The program was proved to be effective and may serve as a model to help other communities establish similar programs.

Carbon dioxide laser vaporization: relationship of scar formation to power density.

A direct relationship exists between the power density of a carbon dioxide laser and the thickness of scars it produces in rat skin. Statistically significant positive relationships were noted between laser power and scar thickness at days 14, 21, and 32. The slope of the curve increased as the number of days elapsed. At day 32, the ratio of scar thickness to CO2 laser power density delivered was 0.3 microns/W-cm2. Scar formation took longer for completion at higher wattages of irradiation.

The use of the carbon dioxide laser permits primary closure of contaminated and purulent lesions and wounds.

Excision of contaminated and purulent wounds with the carbon dioxide laser makes it safe to close the wounds primarily when certain steps are observed during the operation. The contaminated surface is sterilized with the defocused beam. The surgeons' and assistants' hands should not touch the contaminated areas, and both should wear two pairs of rubber gloves to protect against accidental contamination. All infected tissue is excised completely, and the wound cleansed by copious irrigation and the defocused laser. The wound may then be safely closed by simple sutures, skin graft, or by the rotation of a vascularized musculocutaneous flap. A series of cases are presented in order to illustrate these points.

The influence of hands-on laser training on usage of the CO2 laser.

A questionnaire was distributed to all participants in the Rochester General Hospital CO2 laser training workshops for surgeons (1982 to January 1985). The results of this study indicate that, while laser training is necessary prior to being able to use the laser, only a small fraction of trainees actually use the laser in their clinical practice. Surgeons who are using the laser do so in a minority of their cases. New incentives for laser usage must be investigated.

Hematoporphyrin derivative fluorescence: photographic techniques for the localization of malignant tissue.

Three simple methods for the detection of malignancy by the photography of hematoporphyrin derivative (HPD) fluorescence are presented. Two methods employ a single lens reflex camera with macrolens and Kodak high-speed Ektachrome (EL 400) film. Both employ a Corning Glass #3482 filter as a barrier on the lens. In method I, a single Kodak Wratten #39 filter is placed over a fluorescent "black light" source (two General Electric F20T12BL 20-W bulbs). In method II, twin electronic flash units (5,500 BCPS unfiltered) with a double thickness of Kodak Wratten #39 filter over them provide the light of excitation. Method III employs an adapted Polaroid SLR 680E Sun camera with two electronic flash units (5,500 BCPS, total unfiltered) rigged with a slave trigger. A Corning Glass #3482 filter is placed on the lens to act as a barrier, and two filters of Kodak Wratten #39 glass are placed on each flash unit. Photographs are taken in a darkened room.

Inexpensive retractors for laser operations.

The sterile tongue depressor and Lucite block have been presented as simple, safe and inexpensive retractors for use in laser operations. Such inexpensive devices are cost effective alternatives to blackened surgical instruments.