Acute Fixation Protocol for High-Energy Tibial Pilon Fractures Decreases Time to Fixation and Lowers Operative Costs Without Affecting Wound Complications and Reoperations.

OBJECTIVES: To determine whether an acute fixation protocol for high-energy tibial pilon fractures increases the rate of wound complications. DESIGN: Retrospective comparative study. SETTING: Urban level 1 trauma center. PATIENTS/PARTICIPANTS: One hundred forty-seven patients with OTA/AO 43B and 43C high-energy tibial pilon fractures treated with open reduction and internal fixation (ORIF). INTERVENTION: Acute (<48 hours) versus delayed ORIF protocols. MAIN OUTCOME MEASUREMENT: Wound complications, reoperations, time to fixation, operative costs, and hospital length of stay (LOS). Patients were compared by protocol, regardless of ORIF timing, for an intention-to-treat analysis. RESULTS: Thirty-five and 112 high-energy pilon fractures were treated under the acute and delayed ORIF protocols, respectively. In the acute ORIF protocol group, 82.9% of patients received acute ORIF versus 15.2% of patients in the standard delayed protocol group. The 2 groups had no observed difference (OD) in the rate of wound complications (OD -5.7%, confidence interval (95% CI) -16.1% to 7.8%; P = 0.56) or reoperations (OD -3.9%, 95% CI, -14.1% to 9.4%; P = 0.76). The acute ORIF protocol group had a shorter LOS (OD -2.0, 95% CI, -4.0 to 0.0; P = 0.02) and lower operative costs (OD $-2709.27, 95% CI, -3582.02 to -1601.16; P < 0.01). On multivariate analysis, wound complications were associated with open fractures (odds ratio 3.36, 95% CI, 1.06-10.69; P = 0.04) and an American Society of Anesthesiologists score >2 (odds ratio 3.68, 95% CI, 1.07-12.67; P = 0.04). CONCLUSION: This study suggests that an acute fixation protocol for high-energy pilon fractures decreases time to definitive fixation, lowers operative costs, and shortens hospital LOS without affecting wound complications or reoperations. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Early Outcomes of Operative Versus Nonoperative Management of Stress-Positive Minimally Displaced Lateral Compression Type 1 Pelvic Ring Injuries.

OBJECTIVES: To compare the early outcomes of patients with stress-positive minimally displaced lateral compression type 1 (LC1b) pelvic ring injuries managed with or without operative fixation. DESIGN: Retrospective comparison study. SETTING: Level 1 trauma center. PATIENTS/PARTICIPANTS: Forty-three patients with LC1b injuries. INTERVENTION: Operative versus nonoperative. MAIN OUTCOME MEASUREMENTS: Discharge to subacute rehabilitation (SAR); 2- and 6-week pain visual analog score, opioid use, assistive device use, percentage of normal single assessment numerical evaluation, SAR status; fracture displacement; and complications. RESULTS: The operative group did not differ in age, gender, body mass index, high-energy mechanism, dynamic displacement stress radiographs, complete sacral fractures, Denis sacral fracture classification, Nakatani rami fracture classification, follow-up length, or American Society of Anesthesiologists classification. The operative group was less likely to be using an assistive device at 6 weeks [observed difference (OD) -53.9%, 95% confidence interval (CI) -74.3% to -20.6%, OD/CI 1.00, P = 0.0005], less likely to remain in an SAR at 2 weeks (OD -27.5%, CI, -50.0% to -2.7%, OD/CI 0.58, P = 0.02), and had less fracture displacement at follow-up radiographs (OD -5.0 mm, CI, -9.2 to -1.0 mm, OD/CI 0.61, P = 0.02). There were no other differences in outcomes between treatment groups. Complications occurred in 29.6% (n = 8/27) of the operative group compared with 25.0% (n = 4/16) of the nonoperative group resulting in 7 and 1 additional procedures, respectively. CONCLUSIONS: Operative treatment was associated with early benefits over nonoperative management, including shorter time using assistive devices, less SAR use, and less fracture displacement at follow-up. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Observations on heterodonty within the dentition of the Atlantic Sharpnose Shark, Rhizoprionodon terraenovae (Richardson, 1836), from the north-central Gulf of Mexico, USA, with implications on the fossil record.

The Atlantic Sharpnose Shark, Rhizoprionodon terraenovae (Richardson, 1836), is the most common small coastal requiem shark in the north-central Gulf of Mexico, USA. Despite this fact, little is known about the dental variation within this taxon. To help rectify this shortcoming, we examined 126 male and female R. terraenovae jaws sets across all maturity stages to document the various types of heterodonty occurring in the dentition of this taxon. Quantitative data gathered from a subset of our sample allowed for us to place teeth within the dentition of R. terraenovae into standardized upper and lower parasymphyseal/symphyseal, anterior lateral, and posterior tooth groups. As with all carcharhinid sharks, the dentition of R. terraenovae exhibits monognathic and dignathic heterodonty. We also observed significant ontogenetic heterodonty in the species, as the teeth and dentition progress through five generalized developmental stages as the shark matures. The ontogenetic development of serrations on the teeth appears to be closely related to documented dietary changes as the shark matures. Initial diets are comprised of high percentages of invertebrate prey like shrimp, crabs, and squid, but this transitions through ontogeny to a diet that is more reliant on fishes. We also provide the first documentation of gynandric heterodonty in mature male R. terraenovae, with development of these seasonal teeth likely enabling a male to grasp female sharks during copulation. Our analysis revealed a tremendous amount of variation in the dentition of R. terraenovae, which has direct implications on the taxonomy of fossil Rhizoprionodon. A comparison of the jaws in our sample to those of the extant species of Rhizoprionodon and the morphologically similar Loxodon, Scoliodon, and Sphyrna allowed us to formulate a list of generic-level characteristics to assist with the identification of isolated teeth. When applied to the fossil record, it is shown that some species previously assigned to Rhizoprionodon likely belong to one of the other aforementioned genera. The earliest occurrence of unequivocal Rhizoprionodon teeth in the fossil record are those of the Eocene †R. ganntourensis (Arambourg, 1952), the oldest records of which occur in early Ypresian deposits in Alabama and Mississippi, USA. The early Eocene occurrence of unequivocal fossil Rhizoprionodon teeth in Alabama predates the first occurrence of Negaprion, Galeocerdo, and Carcharhinus teeth in the state, supporting published molecular and morphological phylogenies positing a basal position for Rhizoprionodon within the Carcharhinidae.

Combined Anterior-Posterior versus Posterior-Only Fixation of Stress-Positive Minimally Displaced Lateral Compression Type 1 (LC1) Pelvic Ring Injuries.

OBJECTIVES: To compare hospital outcomes and late displacement between stress-positive minimally displaced lateral compression type 1 (LC1) pelvic ring injuries treated with combined anterior-posterior versus posterior-only fixation. DESIGN: Retrospective comparative cohort. SETTING: Urban level-one trauma center. PATIENTS/PARTICIPANTS: LC1 injuries managed operatively. INTERVENTION: Anterior-posterior versus posterior-only fixation. MAIN OUTCOME MEASUREMENTS: Physical therapy (PT) clearance, discharge location, hospital length of stay (LOS), inpatient morphine equivalent doses (MED), and fracture displacement at follow-up. RESULTS: Groups were similar in demographic and injury characteristics (age, high energy mechanism, ASA score, stress displacement, and rami/sacral fracture classifications). Anterior-posterior fixation resulted in longer operative times (median difference (MD): 27.0 minutes, 95% confidence interval (CI): 17.0 to 40.0, P < 0.0001) and had a trend of increased estimated blood loss (MD: 10 mL, CI: 0 to 30, P = 0.07). Patients with anterior-posterior fixation required less inpatient MEDs (MD: -180.0, CI: -341.2 to -15.0, P = 0.02), were more likely to clear PT by discharge (100% vs. 70%, proportional difference (PD): 30%, CI: 2.0%-57.2%, P = 0.02), were less likely to discharge to rehabilitation facilities (0% vs. 30%, PD: 30%, CI: 2.0%-57.2%, P = 0.02), and had a trend of less days to clear PT after surgery (MD: -1, CI: -2 to 0, P = 0.09) and decreased LOS (MD: -1, CI: -4 to 1, P = 0.17). Late fracture displacement did not differ between groups. CONCLUSION: Anterior-posterior fixation of LC1 injuries was associated with an improved early hospital course-specifically, reduced inpatient opioid use and an increased number of patients who could clear PT and discharge home. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Nonoperative Management of Minimally Displaced Lateral Compression Type 1 Pelvic Ring Injuries With and Without Occult Instability.

OBJECTIVES: To determine the association of pelvic fracture displacement on lateral stress radiographs (LSRs) with the hospital course of patients with minimally displaced lateral compression type 1 (LC1) pelvic injuries. DESIGN: Retrospective review. SETTING: Level 1 trauma center. PATIENTS/PARTICIPANTS: Twenty-eight adult patients with minimally displaced (<1 cm) LC1 injuries. INTERVENTION: Nonoperative management. MAIN OUTCOME MEASUREMENTS: Delayed operative fixation, days to clear physical therapy, mobilization, hospital length of stay, and total hospital opioid morphine equivalent dose. RESULTS: LSR displacement was correlated with delayed operative fixation [r = 0.23, 95% confidence interval (CI) 0.05-1.11; P = 0.01], days to clear PT (r = 0.13, CI 0.01-0.28; P = 0.02), length of stay (r = 0.13, CI 0.006-0.26; P = 0.02), and opioid morphine equivalent dose (r = 19.4, CI 1.5-38.1; P = 0.03). A receiver operating characteristic curve for delayed operative fixation over LSR displacement had an area under the curve of 0.87. The LSR displacement threshold that maximized sensitivity and specificity for detecting patients who required delayed fixation was 10 mm (100% sensitivity and 78% specificity). Ten of the 15 patients with ≥10 mm of displacement on LSRs underwent delayed operative fixation for pain with mobilization at a median of 6 days (interquartile range 3.7-7.5). Patients with ≥10 mm of displacement on LSRs took longer to clear PT, took longer to walk 15 feet, had longer hospital stays, and used more opioids. CONCLUSIONS: LC1 fracture displacement on LSRs is associated with delayed operative fixation, difficulty mobilizing secondary to pain, longer hospital stays, and opioid use. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Clinical and pathological comparison of Astragalus lentiginosus and Ipomoea carnea poisoning in goats.

The indolizidine alkaloid swainsonine, found in some Astragalus and Oxytropis (i.e., locoweed) species, is a potent cellular glycosidase inhibitor that often poisons livestock. Other toxic genera such as some Ipomoea species also contain swainsonine as well as calystegines which are similar polyhydroxy alkaloids. The toxicity of calystegines is poorly characterized; however, they are also potent glycoside inhibitors capable of intestinal and cellular glycoside dysfunction. The objective of this study was to directly compare A. lentiginosus and I. carnea poisoning in goats to better characterize the role of the calystegines. Three groups of four goats each were treated with ground alfalfa (control), I. carnea or A. lentiginosus to obtain daily doses of 0.0, 1.5, and 1.5 mg swainsonine/kg bw per day, respectively, for 45 days. Animals were observed daily and weekly body weights, serum enzyme activities, and serum swainsonine concentrations were determined. At day 45 all animals were euthanized and necropsied. Goats treated with A. lentiginosus and I. carnea developed clinical disease characterized by mild intention tremors and proprioceptive deficits. Goats treated with A. lentiginosus developed clinical disease sooner and with greater consistency. No differences in body weight, serum swainsonine concentrations and serum enzyme activity were observed between goats treated with A. lentiginosus and I. carnea. Additionally, there were no differences in the microscopic and histochemical studies of the visceral and neurologic lesions observed between goats treated with A. lentiginosus and I. carnea. These findings suggest that I. carnea-induced clinical signs and lesions are due to swainsonine and that calystegines contribute little or nothing to toxicity in goats in the presence of swainsonine.

Atrazine movement in corn cultivated soil using HYDRUS-2D: A comparison between real and simulated data.

Atrazine is an herbicide that is applied in corn around the world and in sugarcane in Brazil. It is known to be hazardous for animals' health, mobile in the soil, and its analysis is considered expensive and onerous. Solute movement studies are essential to provide information about dangerous molecules movement, which can avoid contamination. While field investigations demand time and financial resources, numerical models are an alternative to describe water and solute distribution in the soil profile. Thus, the objective of this work was to use HYDRUS 2-D model for simulations of atrazine movement in containers packed with tropical soil cultivated with corn and to compare simulated and observed data through statistical parameters. The research was carried out in a greenhouse during 116 days after planting. Atrazine was analyzed in the soil solution at three different depths to validate HYDRUS-2D. Simulations were carried out using hydraulic properties fitted directly to measured retention data and parameters for corn growing and atmospheric characteristics. The mixed procedure analysis indicated that there are differences in atrazine concentration among depths and along time. In general, atrazine concentration is higher at shallow depths and right after application. However, it is possible to find atrazine in deeper soil layers, which might be a concern regarding contamination. RMSE, Willmott and Pearson coefficients indicated a favorable capacity of the model to simulate atrazine concentration on corn cultivation. HYDRUS-2D is a reliable tool to obtain trends in atrazine movement under these experiment's conditions. The uptake parameters, the crop root growth and distribution parameters depend on further specific studies to better describe the relationship between the plant and atrazine and meteorological parameters need to be updated.

Usefulness Of Glucocorticoids In The Management Of Foreign Body Aspiration.

Foreign body aspiration can be a life-threatening emergency. An aspirated solid or semi-solid object may lodge in the larynx, trachea or other breathing airways. If the object is large enough to cause nearly complete obstruction of the airway, asphyxia may rapidly cause death. We report a 19-year old man admitted with right lower lobe pneumonia who spontaneously expelled a foreign body, one day after admission and glucocorticoids administration. Glucocorticoids should be considered in foreign body aspiration management because improvement of the inflammatory reaction may facilitate expontaneous expulsion or foreign body extraction

Bis-spirolabdane diterpenoids from Leonotis nepetaefolia.

Ten new bis-spirolabdane diterpenoids, leonepetaefolins A-E (1, 3, 5, 7, 9) and 15-epi-leonepetaefolins A-E (2, 4, 6, 8, 10), together with eight known labdane diterpenoids (11-18) as well as two known flavonoids, apigenin and cirsiliol, were isolated from the leaves of Leonotis nepetaefolia. The structures of the new compounds were determined on the basis of 1D- and 2D-NMR experiments including (1)H, (13)C, DEPT, (1)H-(1)H COSY, HSQC, HMBC, and NOESY. The absolute configuration of an epimeric mixture of 1 and 2 was determined by X-ray crystallographic analysis. The compounds isolated were evaluated for their binding propensity in several CNS G-protein-coupled receptor assays in vitro.

Receptor screening technologies in the evaluation of Amazonian ethnomedicines with potential applications to cognitive deficits.

ETHNOPHARMACOLOGICAL RELEVANCE: Amazonian peoples utilize a variety of psychoactive plants that may contain novel biologically active compounds. Efforts to investigate such remedies in terms of neuropharmacology have been limited. AIM OF THIS STUDY: This study identified Amazonian ethnomedicines with potential for the treatment of cognitive deficits in schizophrenia and dementias, and characterized their interactions with CNS neurotransmitter receptors in vitro. MATERIALS AND METHODS: Approximately 300 Amazonian species with folk uses or constituents indicative of central nervous system activity were incorporated into a database constructed from literature searches, herbarium surveys, and interviews with traditional practitioners. Approximately 130 of these targeted species were collected in Loreto province, Peru, and 228 fractions derived from them were screened in 31 radioreceptor assays via the resources of the NIMH Psychoactive Drug Screening Program. A subset was also screened in functional assays at selected serotonin, muscarinic, and adrenergic receptors. RESULTS: Ninety-one samples displayed ≥60% inhibition of radioligand binding activity in receptor assays; 135 samples displayed agonist or antagonist activity (or both) in functional assays. CONCLUSIONS: Potential CNS activity was detected in about 40% of the samples screened, with some correlations to both folk uses and phytochemical constituents. These results may point to novel and potentially therapeutic CNS active compounds.

Do Mexican Americans perceive environmental issues differently than Caucasians: a study of cross-ethnic variation in perceptions related to water in Tucson.

Little is known about the environmental perceptions of our nation's Mexican and Mexican American population, especially in the area of water quality. We examined these perceptions to determine the extent to which Caucasians and Mexican Americans living in the Tucson, Arizona, metropolitan area differ in their perceptions of water quality-related risk, inequity, trust, and participation in civic activities. Ethnic variations in perceptions toward inequity, trust, and public participation were observed even when socioeconomic variation between Caucasians and Mexican Americans was controlled. However, significant ethnic variations in perceptions of water quality-related risks were observed only when socioeconomic variation was not controlled. Implications of these findings to environmental justice efforts in Mexican American communities are discussed.

The sensorimotor system, part I: the physiologic basis of functional joint stability.

OBJECTIVE: To define the nomenclature and physiologic mechanisms responsible for functional joint stability. DATA SOURCES: Information was drawn from an extensive MEDLINE search of the scientific literature conducted in the areas of proprioception, neuromuscular control, and mechanisms of functional joint stability for the years 1970 through 1999. An emphasis was placed on defining pertinent nomenclature based on the original references. DATA SYNTHESIS: Afferent proprioceptive input is conveyed to all levels of the central nervous system. They serve fundamental roles in optimal motor control and sensorimotor control over functional joint stability. CONCLUSIONS/APPLICATIONS: Sensorimotor control over the dynamic restraints is a complex process that involves components traditionally associated with motor control. Recognizing and understanding the complexities involved will facilitate the continued development and institution of management strategies based on scientific rationales.

The Sensorimotor System, Part II: The Role of Proprioception in Motor Control and Functional Joint Stability.

OBJECTIVE: To discuss the role of proprioception in motor control and in activation of the dynamic restraints for functional joint stability. DATA SOURCES: Information was drawn from an extensive MEDLINE search of the scientific literature conducted in the areas of proprioception, motor control, neuromuscular control, and mechanisms of functional joint stability for the years 1970-1999. DATA SYNTHESIS: Proprioception is conveyed to all levels of the central nervous system. It serves fundamental roles for optimal motor control and sensorimotor control over the dynamic restraints. CONCLUSIONS/APPLICATIONS: Although controversy remains over the precise contributions of specific mechanoreceptors, proprioception as a whole is an essential component to controlling activation of the dynamic restraints and motor control. Enhanced muscle stiffness, of which muscle spindles are a crucial element, is argued to be an important characteristic for dynamic joint stability. Articular mechanoreceptors are attributed instrumental influence over gamma motor neuron activation, and therefore, serve to indirectly influence muscle stiffness. In addition, articular mechanoreceptors appear to influence higher motor center control over the dynamic restraints. Further research conducted in these areas will continue to assist in providing a scientific basis to the selection and development of clinical procedures.

Sensorimotor system measurement techniques.

OBJECTIVE: To provide an overview of currently available sensorimotor assessment techniques. DATA SOURCES: We drew information from an extensive review of the scientific literature conducted in the areas of proprioception, neuromuscular control, and motor control measurement. Literature searches were conducted using MEDLINE for the years 1965 to 1999 with the key words proprioception, somatosensory evoked potentials, nerve conduction testing, electromyography, muscle dynamometry, isometric, isokinetic, kinetic, kinematic, posture, equilibrium, balance, stiffness, neuromuscular, sensorimotor, and measurement. Additional sources were collected using the reference lists of identified articles. DATA SYNTHESIS: Sensorimotor measurement techniques are discussed with reference to the underlying physiologic mechanisms, influential factors and locations of the variable within the system, clinical research questions, limitations of the measurement technique, and directions for future research. CONCLUSIONS/RECOMMENDATIONS: The complex interactions and relationships among the individual components of the sensorimotor system make measuring and analyzing specific characteristics and functions difficult. Additionally, the specific assessment techniques used to measure a variable can influence attained results. Optimizing the application of sensorimotor research to clinical settings can, therefore, be best accomplished through the use of common nomenclature to describe underlying physiologic mechanisms and specific measurement techniques.

The Effects of Sex, Joint Angle, and the Gastrocnemius Muscle on Passive Ankle Joint Complex Stiffness.

OBJECTIVE: To assess the effects of sex, joint angle, and the gastrocnemius muscle on passive ankle joint complex stiffness (JCS). DESIGN AND SETTING: A repeated-measures design was employed using sex as a between-subjects factor and joint angle and inclusion of the gastrocnemius muscle as within-subject factors. All testing was conducted in a neuromuscular research laboratory. SUBJECTS: Twelve female and 12 male healthy, physically active subjects between the ages of 18 and 30 years volunteered for participation in this study. The dominant leg was used for testing. No subjects had a history of lower extremity musculoskeletal injury or circulatory or neurologic disorders. MEASUREMENTS: We determined passive ankle JCS by measuring resistance to passive dorsiflexion (5 degrees.s(-1)) from 23 degrees plantar flexion (PF) to 13 degrees dorsiflexion (DF). Angular position and torque data were collected from a dynamometer under 2 conditions designed to include or reduce the contribution of the gastrocnemius muscle. Separate fourth-order polynomial equations relating angular position and torque were constructed for each trial. Stiffness values (Nm.degree(-1)) were calculated at 10 degrees PF, neutral (NE), and 10 degrees DF using the slope of the line at each respective position. RESULTS: Significant condition-by-position and sex-by-position interactions and significant main effects for sex, position, and condition were revealed by a 3-way (sex-by-position, condition-by-position) analysis of variance. Post hoc analyses of the condition-by-position interaction revealed significantly higher stiffness values under the knee-straight condition compared with the knee-bent condition at both ankle NE and 10 degrees DF. Within each condition, stiffness values at each position were significantly higher as the ankle moved into DF. Post hoc analysis of the sex-by-position interaction revealed significantly higher stiffness values at 10 degrees DF in the male subjects. Post hoc analysis of the position main effect revealed that as the ankle moved into dorsiflexion, the stiffness at each position became significantly higher than at the previous position. CONCLUSIONS: The gastrocnemius contributes significantly to passive ankle JCS, thereby providing a scientific basis for clinicians incorporating stretching regimens into rehabilitation programs. Further research is warranted considering the cause and application of the sex-by-position interaction.

Calcium-stimulated insulin secretion in diffuse and focal forms of congenital hyperinsulinism.

OBJECTIVES: To identify infants with hyperinsulinism caused by defects of the beta-cell adenosine triphosphate-dependent potassium channel complex and to distinguish focal and diffuse forms of hyperinsulinism caused by these mutations. STUDY DESIGN: The acute insulin response to intravenous calcium stimulation (CaAIR) was determined in 9 patients <20 years with diffuse hyperinsulinism caused by defective beta-cell sulfonylurea receptor (SUR1(-/-)), 3 patients with focal congenital hyperinsulinism (6 weeks to 18 months), a 10-year-old with insulinoma, 5 with hyperinsulinism/hyperammonemia syndrome caused by defective glutamate dehydrogenase (6 months to 28 years), 4 SUR1(+/-) heterozygotes with no symptoms, and 9 normal adults. Three infants with congenital focal disease, 1 with diffuse hyperinsulinism, and the child with insulinoma underwent selective pancreatic intra-arterial calcium stimulation with hepatic venous sampling. RESULTS: Children with diffuse SUR1(-/-) disease and infants with congenital focal hyperinsulinism responded to CaAIR, whereas the normal control group, patients with hyperinsulinism/hyperammonemia syndrome, and SUR1(+/-) carriers did not. Selective arterial calcium stimulation of the pancreas with hepatic venous sampling revealed selective, significant step-ups in insulin secretion that correlated anatomically with the location of solitary lesions confirmed surgically in 2 of 3 infants with congenital focal disease and in the child with insulinoma. Selective arterial calcium stimulation of the pancreas with hepatic venous sampling demonstrated markedly elevated baseline insulin levels throughout the pancreas of the infant with diffuse hyperinsulinism. CONCLUSIONS: The intravenous CaAIR is a safe and simple test for identifying infants with diffuse SUR1(-/-) hyperinsulinism or with focal congenital hyperinsulinism. Preoperative selective arterial calcium stimulation of the pancreas with hepatic venous sampling can localize focal lesions causing hyperinsulinism in children. The combination of these calcium stimulation tests may help distinguish focal lesions suitable for cure by local surgical resection.

Trypanosoma cruzi meningoencephalitis in HIV-infected patients.

Five cases of Trypanosoma cruzi meningoencephalitis in HIV-infected patients are reported. All patients presented with mass lesions on head computed tomographic scan, trypanosomes in the cerebrospinal fluid and failure to respond to antitoxoplasmosis therapy. Benznidazole therapy was associated with clinical improvement in 1 patient. Another 4 patients had T cruzi identified in a peripheral smear. T cruzi needs to be considered in the differential diagnosis of HIV-infected patients with central nervous system mass lesions if they have a history of appropriate exposure.

Variant in sulfonylurea receptor-1 gene is associated with high insulin concentrations in non-diabetic Mexican Americans: SUR-1 gene variant and hyperinsulinemia.

The high-affinity sulfonylurea receptor (SUR1) gene regulates insulin secretion and may play a role in type 2 diabetes. A silent variant in exon 31 of SUR1 (AGG-->AGA) was detected by single-strand conformational polymorphism and genotypes were determined for 396 Mexican American subjects (289 non-diabetic). The normal and mutant alleles were designated G and A, respectively. Among non-diabetics, those with the AA genotype had higher fasting insulin values than those with the AG and GG genotypes (113.4 pmol/l for AA vs 82.8 pmol/l for AG/GG, P=0.043). Similar results were observed for 2-h insulin (849.6 pmol/l for AA vs 498.6 pmol/l for AG/GG, P=0.0003) and for the proinsulin to specific insulin ratio (0.068 for AA vs 0.056 for AG/GG, P=0.030). Specific insulin levels also differed significantly across the three genotypic classes (P=0.021). No differences in fasting glucose, body mass index, or waist circumference according to genotype were noted. Two-hour glucose was modestly higher in individuals with the AA genotype. Since we have previously reported linkage between SUR1 and hyperglycemia, the present association between a SUR1 variant and hyperinsulinemia in normal individuals from a high diabetes risk ethnic group raises the possibility of primary insulin hypersecretion as an antecedent of type 2 diabetes in at least some individuals from this population.

National survey of clinical and subclinical mastitis in Jamaican dairy herds, 1985-1986.

Between April 1985 and August 1986, 89 Jamaican dairy herds with 10 or more cows were visited, 1,645 lactating cows were examined using the CMT test and 254 composite milk samples collected for bacteriological examination. Widespread management faults were noted, especially of milking machine usage and maintenance and the abuse of antibiotics. Fifty-six per cent of all quarters were found to have CMT scores of one or higher, 0.8% showed clinical mastitis and 3.2% were blind. The most common bacterial pathogen Staphylococcus aureus, was recovered from 31% of sampled cows. The resultant milk loss from clinical and subclinical mastitis was estimated to be 20% of the potential national production.