Cutaneous and systemic effects of varying doses of brown recluse spider venom in a rabbit model.

OBJECTIVE: To ascertain whether a dose response exists between the dose of brown recluse spider venom (BRSV) and the cutaneous and coagulation effects in a rabbit model. Cutaneous necrosis is a serious complication of brown recluse spider envenomation (spider bite with venom). Disseminated intravascular coagulation (DIC) is a dreaded complication of brown recluse envenomation in humans. New Zealand white (NZW) rabbits have proved to be a model for the study of therapeutic regimens to prevent skin necrosis after spider bites. We studied the venom's effects on the skin and the coagulation mechanism in this rabbit model to determine if a clear dose-response relationship could be established. Establishment of a dose-response relationship is an important first step in determining if the NZW rabbit is a suitable model to study both cutaneous and systemic effects of the venom. DESIGN: Thirty-six NZW rabbits were divided into three groups. One group received a saline injection, and the other two groups received a 4.0 microg or a 10.0 microg dose of purified BRSV intradermally into the skin on the dorsum of the back. METHODS: Blood was collected at baseline, 24, 48, and 72 hours. Tissue specimens were obtained after seven days during the animal necropsy and gross and microscopic pathology examination was conducted to assess tissue damage. Measurements included complete blood count (CBC); platelets; PT; activated partial thromboplastin time (APTT); fibrinogen (clottable, immunological); coagulation factors II, V, VII, VIII, IX, X, XI, XII; anti-thrombin (AT); alpha-2 antiplasmin (AP); Protein C (PC); mixing studies; lupus anticoagulant screening; plasminogen; thrombin-antithrombin; fibrin degradation products (FDP); d-dimer; and thrombin time. RESULTS: Gross pathology results were consistent with previous studies that used higher doses of BRSV. The WBC and platelet counts decreased at 24 hours in the two groups receiving the BRSV (p < 0.05). BRSV produced a dose related prolongation in the APTT (p < 0.05). Levels of fibrinogen as well as factors V, VII, VIII, IX, X, AT, and AP (p < 0.05) were increased in response to the BRSV. Protein C decreased at 24 hours (p < 0.05) and remained low in other time points. Mixing studies corrected the prolonged APTTs to normal ranges. Factor IIXI and XII showed no significant alteration in response to the BRSV. CONCLUSIONS: In the model, both the size and depth of the eschar were dose-related. We also observed a dose related elevation in the APTT that corrected with mixing studies. The dose-response relationship suggests direct interference by a component of the venom, rather than an idiosyncratic response. We did not detect a deficiency of commonly measured coagulation factors or evidence of a lupus anticoagulant. Protein C demonstrated a decrease. Although DIC did not occur in this rabbit model, a dose-related elevation in APTT was noted. The finding that the elevation corrected with mixing studies suggests that a plasma factor is essential in the coagulopathy associated with brown recluse envenomation. Further studies to identify this factor could shed light on human coagulopathy following envenomation.     

Laser laparoscopy—indications,techniques and results

The laser has revolutionized the role of gynaecological laparoscopy from a purely diagnostic one to that of first line operative intervention. Since the first report from Professor Bruhat of the use of the carbon dioxide (CO₂) laser at laparoscopy in 1979, there have been several advances made both in the type of laser used in gynaecology and the techniques employed. Initially used for the treatment of endometriosis and adhesions, the laser has been used in such diverse areas as treatment of polycystic ovarian disease, neosalpingostomies and myomectomies. Another advantage of laser laparoscopy is that it can often lead to a complete withdrawal from, or marked reduction in medication requirements, particularly when used in the treatment for dysmenorrhoea, endometriosis and polycystic ovarian disease. Today, there are few gynaecological procedures that cannot be performed laparoscopically, there-by avoiding all the sequelae associated with laparotomy. The laser as a surgical tool has been at the forefront of minimally invasive surgery. Minimal invasive surgical techniques not only reduce the length of stay in hospital, a crucial factor in today's economic climate, but also reduce post-operative morbidity, decrease the length of convalescence and allow the woman to return more quickly to her normal routine. Paper presented at the Third Congress of the Scandinavian Society for Laser Therapy, October 1991, Orebro, Sweden.     

Achieving optimal aesthetics using contemporary porcelain materials: a case report.

While the selection of an appropriate material contributes to restorative success, a thorough treatment plan with enhanced clinician/technician communication is required to ensure an appropriate and aesthetic result. A concise understanding of the patient's existing condition, desires, and expectations is critical to ensure restorative success. This case presentation demonstrates the clinical and laboratory protocols for the development of predictable, functional, and aesthetic porcelain restorations in treating severely compromised maxillary anterior dentition.     

Bilobed flap reconstruction of the temporal forehead.

The temporal forehead is a particularly challenging area for reconstruction. Temporal forehead skin lies in a broad flat plane that varies in thickness. The eyebrow, scalp hairline, and lateral canthus comprise its aesthetic boundaries and limit the available tissue for repair of defects. Characteristically, skin tumors of the temporal forehead have extensive subclinical spread and their removal leaves large defects. The goal of temporal forehead reconstruction is to recreate the aesthetic boundaries of the forehead and to regain symmetry with the contralateral side. The temporal forehead bilobed flap is a single-stage procedure that takes advantage of the best color match of adjacent tissue and often allows primary closure of the donor sites in relaxed skin tension lines with minimal distortion. Several cases are presented for illustration of the technique.     

Effect of chronic cisplatin administration on phosphate and glucose transport by the renal brush border membrane

Cisplatin (CIS-diamine dichloroplatinum) is a highly nephrotoxic antineoplastic agent which may cause acute renal failure and renal tubular dysfunction. In the present study we have examined the effect of chronic cisplatin administration on sodium-dependent 32P-phosphate and 3H glucose transport by the renal brush border membrane vesicles (BBMV). Our results indicate that both transport mechanisms were significantly reduced at the BBMV following cisplatin therapy due to an increased Km (0.13 +/- 0.09 vs. 0.34 +/- 0.09 mM; p = less than 0.01) without significant change in Vmax (56 +/- 18 vs. 44 +/- 17 pM/mg/s). The results of these studies indicate that cisplatin causes a diffuse renal injury in the proximal segment of the nephron altering both transport mechanisms. Possible mechanisms of cisplatin nephrotoxicity are discussed.     

The acute and chronic toxicity of ten chlorinated organic compounds to the American flagfish (Jordanella floridae)

The acute toxicity (96-hr median lethal concentrations (LC50s) of ten chlorinated isomers of benzene, phenol, ethane, and ethylene to the American flagfish (Jordanella floridae) were determined in both static and flowthrough systems. Chronic toxicity to embryo-larval fish was also estimated from hatching success and post-hatch survival as well as fry growth rates and survival. Maximum acceptable toxicant concentrations (MATC) were estimated where possible. In general, for both acute and chronic toxicity tests, the order of increasing relative toxicity based on the water-borne exposure concentrations was: chloroethanes, chloroethylenes, chlorobenzenes, and chlorophenols. Within groups, more highly chlorinated isomers were usually more toxic. The presence of suspended or colloidal 1,2,4,5-tetrachlorobenzene was observed in acute toxicity testing and affected toxicity estimates.