Survey of bat populations from Mexico and Paraguay for rabies.

A mammalian survey was conducted in Mexico (October 1994-January 1996) and in Paraguay (August 1996-March 1997); a complete specimen was collected for each bat in the survey, including primary voucher specimen, ectoparasites, karyotype, and various frozen tissues. The surveys combined provided 937 brain samples (65 bat species) for rabies diagnosis. One male Lasiurus ega, collected in Paraguay, tested positive for the rabies virus (overall prevalence rate of 0.1%). Nucleotide sequence from a 300 bp region of the rabies nucleoprotein gene was compared with sequence obtained from representative rabies virus samples in the repository at the Centers for Disease Control and Prevention (Atlanta, Georgia, USA). Rabies virus extracted from the brain material of L. ega differed by only one nucleotide from a 300 bp consensus sequence (>99% homology) derived from samples for the variant of rabies virus transmitted by Lasiurus cinereus. Lasiurus ego differed by approximately 15% for the variant transmitted by Desmodus rotundus. Phylogenetic analysis found no evidence to suggest L. ego is a reservoir for rabies antigenic variant 6. The most likely explanation for rabies in L. ega was infection following contact with a rabid L. cinereus.

The validity of quick intraoperative parathyroid hormone assay: an evaluation in seventy-two patients based on gross morphologic criteria.

BACKGROUND: Parathyroidectomy for primary hyperparathyroidism has conventionally required identification of all parathyroid glands with excision of grossly abnormal glands. Using this approach, cure rates exceed 95%. Directed cervical exploration has been advocated using quick intraoperative parathyroid hormone (QPTH) assay with preoperative localization. Adoption of this approach requires validation of the accuracy of QPTH assay. METHODS: Patients with primary hyperparathyroidism undergoing bilateral neck exploration during a 31-month period were reviewed. Uniglandular (UGD) or multiglandular (MGD) disease was determined by gross morphologic criteria. QPTH assays were performed before skin incision and at 5, 10, and 20 minutes after excision of each abnormal gland. A 10-minute QPTH decrease of 50% from baseline levels indicated curative excision. These data were not used to guide extent of exploration or tissue resection. RESULTS: Of 72 patients, 55 (76%) had UGD and 17 (24%) had MGD. QPTH assay accurately predicted the disease state in 89%. Four (7%) UGD patients did not have an appropriate QPTH decline at 10 minutes. Four (24%) MGD patients had an inappropriate QPTH decline at 10 minutes. CONCLUSIONS: Using QPTH guided exploration, 6% (4 of 72) of patients would undergo unnecessary extended exploration and 6% (4 of 72) (95% CI, 1% to 13%) may require reoperation for unidentified MGD. These results validate the accuracy of QPTH assay.

Complex aortofemoral prosthetic infections: the role of autogenous superficial femoropopliteal vein reconstruction.

BACKGROUND: With increasing experience, we have encountered patients with complex aortofemoral prosthetic infections in whom extra-anatomic bypass (EAB) is not an option. HYPOTHESIS: Autogenous superficial femoropopliteal vein (SFPV) aortic reconstruction provides a limb-saving and lifesaving alternative with acceptable morbidity and mortality. DESIGN: Retrospective review. SETTING: University-based county, private, and Veterans Affairs hospitals. PATIENTS: Seventeen patients with infected aortofemoral bypasses in whom conventional EAB was impossible because of infection of previously placed EAB, massive groin and/or thigh sepsis, or both. MAIN OUTCOME MEASURES: Morbidity and mortality. RESULTS: Multiple previous operations were common (mean, 4 per patient) and included EAB (n = 11), replacement aortofemoral bypass (n = 4), prosthetic femoropopliteal bypass (n = 7), and thoracobifemoral bypass (n = 1); all bypasses became infected. Overall, 11 patients had sepsis at the time of presentation. Of the patients with massive groin infection, 7 had extensive deep infections involving most of the proximal thighs or retroperitoneum, 4 had enterocutaneous fistulae, and 2 had necrotizing fasciitis of the lower abdomen and thigh. Polymicrobial infections were common (n = 9). Four patients (24%) died in the perioperative period, 8 (47%) suffered major complications, and 4 (24%) underwent major amputations. Mortality in this group of patients was 3 times that of all other patients undergoing autogenous SFPV aortic reconstruction for prosthetic infection (8%). Amputation rates were also increased (24% vs 6%). The mean+/-SD follow-up time is 23+/-21 months. All patients maintained patent SFPV reconstructions. CONCLUSIONS: In the setting of complex aortofemoral prosthetic infections, autogenous SFPV aortic reconstruction is a useful option for patients in whom EAB is impossible and limb loss and/or death would be inevitable without revascularization.

The development of a clinically relevant canine model of postperfusion syndrome.

Investigation into the complex etiology of the postperfusion syndrome (PPS) has been limited by access to only retrospective human case studies, and performance of animal studies that examine biochemical predictors of injury rather than the PPS itself. To determine whether a reproducible canine model of the clinical syndrome was possible, seven dogs underwent cardiopulmonary bypass (CPB) with a bubble oxygenator for 0 (n = 1, sham), 2 (n = 1), 4 (n = 1), and 6 (n = 4) hours. Arterial oxygenation, chest radiographs, serum creatinine, and total leukocyte and platelet counts continued to change through the second postoperative day, illustrating the need for prolonged follow-up (48 hours) to accurately detect postperfusion organ dysfunction. The dogs that did not undergo CPB for 6 hours (n = 3) did not develop important pulmonary dysfunction postoperatively, but three of the four dogs undergoing 6 hours of CPB developed profound, persistent, arterial hypoxemia associated with radiographic, histologic, and hemodynamic evidence of severe PPS. Early evidence of renal dysfunction was also apparent within 84 hours of 6 hour CPB. It is concluded that the canine long duration (6 hour) CPB model, with prolonged (48 hour) postoperative monitoring, generates a reproducible, clinically relevant model of human PPS.

Nonparallel nephrotoxicity dose-response curves of aminoglycosides.

Nephrotoxicity comparisons of aminoglycosides in rats, utilizing large multiples of human doses, have indicated an advantage for netilmicin. However, no nephrotoxicity advantage of netilmicin has been demonstrated at the lower doses used in clinics. Some high-dose studies in rats have also suggested that the slope of the nephrotoxicity dose-response curve of netilmicin was less steep than the slopes of other aminoglycosides. Therefore, the slopes of the nephrotoxicity dose-response curves of gentamicin, amikacin, and netilmicin were compared in 200 rats at low multiples (one to five times) of human clinical doses. Histopathological evaluations of both kidneys from each rat revealed that netilmicin produced equivalent or greater nephrotoxicity as compared with gentamicin and amikacin and that the slope of the nephrotoxicity dose-response curve of netilmicin was approximately one-half as steep as the slopes of amikacin and gentamicin, which were parallel. The distribution of casts excreted in the urine after 2 weeks of dosing and the terminal gross observations corroborated the flatter dose-response slope of netilmicin. Nephrotoxicity advantages predicted by high-dose comparisons with netilmicin in rats are apparently a function of its less steep dose-response slope and therefore may have no relevance to lower doses.

Comparative low-dose nephrotoxicities of gentamicin, tobramycin, and amikacin.

Most investigations of the comparative nephrotoxicities of aminoglycosides in animals have utilized large multiples of the human dose. Furthermore, many of these assessments have used only one or two dose levels and have not described a dose-response comparison among antibiotics. Because of this lack of comparative dose-response data over a range of low multiples of the human dose, the nephrotoxicities of gentamicin, tobramycin, and amikacin were investigated in 180 rats, utilizing doses ranging from one to seven times the equivalent human clinical doses. Histopathological evaluations of both kidneys from each rat were scored without knowledge of the treatment, and statistical analyses of the results indicated that a linear and parallel dose-response relationship existed for each drug, the relative nephrotoxicity over the range of doses analyzed was gentamicin > tobramycin > amikacin (P = 0.0001), and, unlike amikacin, the human dose equivalents (milligrams per kilogram) of gentamicin and tobramycin were significantly nephrotoxic in rats (P < 0.05).

Butorphanol/acetaminophen double-blind study in postoperative pain.

An oral butorphanol/acetaminophen (4 mg/650 mg) combination product was evaluated for analgesic activity in 120 postoperative patients employing a double-blind experimental design. The combination product was significantly (p less than 0.05) superior to either butorphanol (4 mg) or acetaminophen (650 mg) as well as placebo. Except for acetaminophen which was only significantly different (p less than 0.05) from placebo at 2 hours according to pain relief, all other treatments were superior to placebo over the entire 4 hour observation period. The data demonstrate that butorphanol and acetaminophen have at least additive analgesic activity with a suggestion of synergism. A single tablet dose of the combination product (butorphanol 2 mg/acetaminophen 325 mg) was evaluated in a second study involving 60 patients and was significantly (p less than 0.05) superior to placebo. Both studies demonstrate that the butorphanol/acetaminophen combination product has potent analgesic activity with a minimal side effect profile.