Re-epithelialization of the rat cornea is accelerated by blockade of opioid receptors

A native opioid peptide, [Met⁵]-enkephalin, termed opioid growth factor (OGF), serves as a constitutively expressed and autocrine produced inhibitory molecule related to developing, neoplastic, renewing, and healing tissues. The present study was designed to examine the effects of interfering with opioid–receptor interaction during re-epithelialization of the cornea in the rat using both systemic injections and topical applications of the potent opioid antagonist naltrexone (NTX). A 4 mm diameter epithelial defect was made in the center of the rat cornea. NTX injected twice daily or applied as eyedrops four times daily significantly accelerated re-epithelialization compared to controls. Beginning as early as 8 h after wounding, both the systemic and topical NTX treatment groups had defects that were approximately 10% to 67% smaller than control abrasions at the time points examined. Similarly, the rate of healing for the NTX groups was 4.7- and 2.8-fold greater than controls for systemic and topical paradigms, respectively. The incidence of complete re-epithelialization in animals given systemic administration of NTX was markedly accelerated in comparison to control rats; however, differences in incidence of repair between NTX and control groups receiving topical application were not observed. These results show that native opioid peptides function in wound healing, and exert a tonically inhibitory influence at the receptor level on repair of corneal epithelial injuries.     

Muscle power after glucose-potassium loading in undernourished patients

The force-frequency characteristics and maximal relaxation rate of the adductor pollicis muscle were measured before and after 48 hours of intravenous loading with glucose (104.5 kJ (25 kcal)/kg/24 h) and potassium (20 mmol(mEq)/500 ml glucose) in eight undernourished patients about to undergo surgery. Both variables of skeletal muscle performance, which were depressed when compared with data from 100 healthy volunteers, improved significantly after glucose-potassium loading. The improvement was accompanied by restoration of muscle glycogen values and return of respiratory exchange ratios towards unity. These results imply that if muscle power is a yardstick for preoperative nutritional rehabilitation then a simple regimen of energy-electrolyte repletion may be cost effective in preparing undernourished patients for major surgery.     

Residual activity of permethrin on cattle as determined by mosquito bioassays

The residual effectiveness against laboratory-reared female Anopheles quadrimaculatus mosquitoes of a synthetic pyrethroid (permethrin) applied to cattle was determined. Twenty-four-hour postexposure mortality and the degree of successful blood engorgement were determined by exposing mosquitoes for 10 min to cattle. Three replicated assays were conducted and mortality determined at 1, 2, 5, 7, 14 and 21 days after each treatment with an oil-based formulation of permethrin (DeLice) or with an emulsifiable concentrate (Atroban) applied at label rates. Mosquito mortality ranged from 79 to 85% (1 day postapplication) to 12-38% (21 days postapplication).     

Metal-polysiloxane shields for radiation therapy of maxillo-facial tumors

In the treatment of some head and neck lesions with high-intensity radiation (teletherapy), an essential procedure is the application of an individually customized shielding appliance, which is designed, modeled, and formed into a working extra- or intraoral stent for the purpose of sparing healthy tissues. The present state of the art is slow and technique intensive, which can add to patient discomfort and inconvenience during molding and fabrication. A new formulation is described, which offers speed and ease of forming a moldable composite stent especially for intraoral use. Interleaved stacks of calibrated thin radiochromic film strips and soft-tissue-simulating plastic (polystyrene) layers gave a means of mapping one- or two-dimensional profiles of dose distributions adjacent to the high-density shielding materials using a spectrophotometer equipped with a gel scanner or a scanning laser-beam microdensitometer. Tests using collimated gamma-ray beams from a 60Co teletherapy unit were made in order to measure the dose distribution near interfaces of tissue-simulating polymer and the composite stent material with and without mixtures of metals (Ag-Cu and Sn-Sb). These results show that quickly formed composites made of a flexible resin with high concentrations of powdered spherical metal alloys provide effective custom-designed shielding, and, with a thin overlayer of the resin without metal, a diminished back-scattered radiation dose to normal tissues. An example of a successful formulation is a mixture of 90% by weight Ag-Cu alloy powder in a vinyl polysiloxane resin. This material is a moldable putty which, upon polymerization, forms a rigid elastomeric material, providing a half-value layer of approximately 2.5 to 2.8 cm for a gamma-ray beam from a 60Co source.     

Surgical treatment of the incontinent female patient with myelomeningocele

Surgical therapy was required for 42 incontinent female patients with myelomeningocele who had urodynamically documented high pressure bladders. Conservative treatment consisting of cholinolytic and alpha-adrenergic agents, and intermittent self-catheterization had failed. The surgical approach consisted of perivesical denervation (for hyperreflexia), Burch bladder neck suspension, enlargement cystoplasty and ureteral reimplantation when required. Among 33 patients (79 per cent) there was no incontinence on intermittent self-catheterization and 6 (14 per cent) had improvement with rare urgency or stress incontinence. In 3 patients (7 per cent) sphincteric incompetence required a transvaginal sling procedure.     

Biotransformation of glyceryl trinitrate and elevation of cyclic GMP precede glyceryl trinitrate-induced vasodilation.

In this study, we examined glyceryl trinitrate (GTN) biotransformation and cyclic GMP elevation in vascular smooth muscle before onset of GTN-induced relaxation. Isolated rabbit aortic strips (RAS) and strips of bovine pulmonary artery (BPA) and bovine pulmonary vein (BPV) were contracted submaximally and incubated with [3H]GTN. Before onset of GTN-induced vasodilation, the tissues were freeze-clamped and then analyzed for GTN, glyceryl-1,2-dinitrate (1,2-GDN), and glyceryl-1,3-dinitrate (1,3-GDN) and for cyclic GMP. Before onset of relaxation of RAS, BPA, and BPV, there was significant biotransformation of GTN to GDN and significant elevation of cyclic GMP. There was significantly greater biotransformation of GTN and elevation of cyclic GMP by BPV than by BPA incubated with the same concentration of GTN, which was temporally related with the more rapid onset of relaxation induced in BPV than in BPA. These results are consistent with the hypothesis that the magnitude of GTN biotransformation before vasodilation is the important determinant of subsequent tissue relaxation. In GTN biotransformation before vasodilation, there was preferential formation of 1,2-GDN. These data indicate that the mechanism of GTN biotransformation to 1,2-GDN is related to elevation of cyclic GMP and subsequent vasodilation.     

Classroom procedures for remediating behavior disorders

Numerous effective interventions for the control of behavior problems in the classroom have been developed. These have included relatively simple strategies such as providing contingent attention for appropriate behaviors and social reprimands or timeout for inappropriate behavior. Behavior control procedures have grown in sophistication to involve more complex systems such as token economies, skill straining strategies, peer interventions, and self-control procedures. Each technique has proved effective in improving classroom behavior, however, the combination of multiple techniques has had the most powerful effects on students. The ultimate goal of remediating complex behavior disorders such that appropriate behavior generalizes across new settings and events will require more comprehensive programs and continued analysis of new and promising practices.     

Naltrexone's influence on neurobehavioral development

The ontogeny of spontaneous motor and sensorimotor behaviors of preweaning rats, as well as ambulation, emotionality, and nociception at weaning (day 21), were studied in rats given chronic administration of 1 or 50 mg/kg naltrexone from birth to day 21. The age at which a specific spontaneous motor behavior or performance initially appeared and the age at which 100% of the animals demonstrated a particular behavior were accelerated in animals given 50 mg/kg naltrexone, but delayed in rats injected with 1 mg/kg naltrexone. In general, ambulation, emotionality, and nociceptive responses were not affected by naltrexone treatment, although the frequency of face-washing in both naltrexone groups and activity cage performance in the 50 mg/kg naltrexone group deviated from control levels. Observations of head-shake and wet-dog shake behaviors in naltrexone-treated animals at 2 hr and 10 hr post-drug injection were similar to controls with the exception of an abnormal increase in the 1 mg/kg naltrexone group at 10 hr. Although these results may imply that endogenous opioid systems play a role in regulating neurobehavioral development, further study is needed to distinguish whether these changes are a consequence of the somatic and morphological alterations known to occur with naltrexone administration or if the timetable of behavioral ontogeny is governed by endorphin-opiate receptor interaction.