Venomous snakebite: past, present, and future treatment options.

BACKGROUND: Venomous snakebites continue to cause great morbidity, and treatment options are confusing the attending physician. In the United States approximately 45,000 snakebites occur each year, of which some 8000 are by 20 species of venomous snakes. METHODS: Information on venomous snakes and snakebite treatment was gathered from the libraries of the Wilderness Medical Society and the Rocky Mountain Center for Wilderness Medicine in Boise, Idaho (co-supported by the Boise State University and the Family Practice Residency of Idaho), as well as from current literature files of physicians practicing wilderness medicine. RESULTS AND CONCLUSIONS: Three genera of venomous snakes account for the majority of poisonous snake envenomations in this country. Most hospitalized victims are bitten either by rattlesnakes or copperheads or by unidentified snakes. Most of these bites occur during the summer months and are found on the extremities. Field treatment focuses on the application of a vacuum extractor and transportation to the nearest medical facility. Although constriction band use can be helpful, tourniquets, incision and suction, and ice therapy are contraindicated. Electric shock therapy is of no use and could cause serious injury. Hospital management focuses on rapid clinical evaluation and laboratory tests to establish the degree of envenomation, looking for clotting abnormalities. If envenomation has occurred and is reactive, polyvalent antivenin should be administered according to the degree of envenomation. Errors in diagnosis and treatment result in increased morbidity and put attending physicians at risk for litigation. Prevention remains the most successful approach to snakebite management.     

Glucose tolerance in women: the effects of age, body composition, and sex hormones.

OBJECTIVE: To determine the separate and interactive effects of age, phase of the menstrual cycle, menopausal hormone status, body fat mass, and regional fat distribution on glucose tolerance in healthy women. DESIGN: Retrospective study. SETTING: The Baltimore Longitudinal Study of Aging. PATIENTS: Two hundred sixty healthy women aged 22-89 years. MEASUREMENTS: Plasma levels of estradiol and progesterone, body mass index (BMI), waist-to-hip ratio (WHR), and plasma glucose values in the fasting state (FPG) as well as 120 minutes after 40 gm/m2 of oral glucose (G120) were measured for each participant. RESULTS: We found a progressive decline in oral glucose tolerance of 0.4 mM (6.7 mg/dL)/decade at G120) in women from early to late adult years, with no relationship to phase of the menstrual cycle and no abrupt change associated with the menopause. Multiple regression analysis revealed significant, independent effects of BMI and WHR on FPG and G120. The influence of age (P less than 0.01) on G120 was stronger than that of the BMI or WHR (P less than 0.05). There was no significant relationship between the levels of endogenous sex hormones and glucose tolerance after adjustments for age, BMI, and WHR. However, women taking oral contraceptives, but not those receiving postmenopausal replacement therapy, did exhibit mildly elevated G120 values. CONCLUSIONS: Age per se, and to a lesser extent BMI and WHR, but not levels of endogenous sex steroids, contribute to the physiological decline in glucose tolerance in older women.     

A mouse model for infectious mononucleosis

Epstein-Barr virus (EBV) is a ubiquitous human gamma-herpesvirus that establishes life-long latency and is associated with lymphoproliferative disorders and the development of several malignancies. EBV infection is frequently, but not always, associated with the development of a syndrome termed infectious mononucleosis. The recent isolation and characterization of a murine gamma-herpesvirus, MHV-68 (gammaHV-68) has provided the first small animal model for studying immunity and pathogenesis of a gamma-herpesvirus in its natural host. MHV-68 has important biological and genetic similarities with the human gamma-herpesviruses. Following intranasal infection of mice with MHV-68, an acute respiratory infection in the lung develops and is cleared, followed by the establishment of latency. Similar to EBV, MHV-68 latency is largely established in B cells, although other cell types can be latently infected. The establishment of latency correlates with a prominent splenomegaly, polyclonal B cell activation with associated autoantibody production, and CD8+ T cell-dominated peripheral blood lymphocytosis, in many aspects mirroring EBV-induced infectious mononucleosis. There are key differences in the MHV-68- and EBV-induced CD8+ T cell responses however. Whereas the expanded CD8+ T cells associated with EBV-induced mononucleosis are largely the outgrowth of T cells responding to lytic viral epitopes elicited during the acute phase of the response, the CD8+ T cell lymphocytosis associated with MHV-68-induced infectious mononucleosis is dominated by an oligoclonal population of T cells expressing Vbeta4+ T cell receptors that are not reactive to acute viral epitopes. The focus of this article will be to highlight the similarities and differences in the infectious mononucleosis syndrome associated with human and murine gamma-herpesviruses.     

Production of type I (alpha/beta) interferon after virus infection of cloned, alloantigen-sensitized mouse T lymphocytes

Mouse T lymphocytes sensitized to alloantigens were cloned by limiting dilution in the presence of interleukin 2. Clones were tested for surface markers Thy-1, Lyt-1 and Lyt-2, and for cytotoxic function. Production of interferon (IFN) by clones either (a) stimulated with allogeneic cells; (b) activated with concanavalin A (Con A); or (c) infected with Semliki Forest virus or Newcastle disease virus were assayed. All clones produced IFN upon Con A stimulation and most after virus infection. Analysis of the IFN produced by a single clone, using anti-IFN antisera, showed that while Con A stimulation induced production of type II IFN (IFN-gamma), the IFN produced after virus infection was type I IFN (IFN-alpha/beta).     

Preliminary assessment of the Con-Bio laser in vivo

A variety of lasers are available for the treatment of pigmented and vascular lesions. This paper presents our preliminary evaluation of the Q-switched 532 nm Con-Bio laser (Continuum Biomedical, Livermore, CA) in a murine model. Mice were anesthetized with intraperitoneal pentobarbital. Laser impacts (10 nsec, 150 mJ max.) were created on the ears at fluences of 1.5, 2, 3, 4, 5, and 6 J/cm 2. Acute study animals were sacrificed 15 min postinjury. Tissues were fixed in formalin and examined via light microscopy. Chronic study animals were allowed to heal for 3 weeks postoperatively. Parameters analyzed included the presence or absence of blistering, hemorrhage, visual assessment of thermal injury, microscopic evidence of vascular coagulation, or disruption and cosmesis. Acute vascular disruption and coagulation were present in all samples. Healing and cosmesis were good at all fluences tested. Tests of the laser in a prefocused mode produced a tissue cavitation effect with a depth of coagulation of 0.73 +/- 0.44 mm and hemorrhage of 0.68 +/- 0.41 mm. A chronic study of the vascular effect on larger vessels (1-2 mm) was conducted on a rabbit ear. Acute disruption was observed, however, all vessels were recanalized when examined grossly and histologically at 3 weeks. These preliminary results suggest that this new laser may be useful for the treatment of cutaneous vascular lesions. Further studies and clinical trials are warranted.     

Using Medicaid fee-for-service data to develop community health center policy

This article presents an analysis of fee-for-service Medicaid data for King County, Washington. This analysis was conducted using Department of Social and Health Services billing records for patients of the community health centers of Seattle-King County (14 primary care sites), the Seattle-King County Department of Public Health (9 primary care sites), and Harborview Medical Center (a large tertiary facility with a primary care outpatient clinic associated with the University of Washington) from January through June, 1992. The complete billing records of all patients who utilized any one of the 24 sites were made available. These records were used to review utilization patterns and patient costs. The implications for community health centers regarding Medicaid managed care, health care reform, and population-based management are discussed.