Population structure in the Culex pipiens complex of mosquitos

Mosquitos of the Culex pipiens complex offer unique opportunities for study of the mechanisms that separate populations and of the possible advantages of the blood-feeding habit. C. pipiens is a polytypic species in which there are at least three major adaptations to environment. The tropical quinquefasciatus (fatigans) is a generalized blood-feeder dependent on the year-round availability of a variety of hosts. The obligate blood-feeding pipiens form of the temperate zone appears to be adapted to feeding upon nesting birds. The autogenous molestus form is essentially non-blood-feeding. Additional variants are present in different parts of the world.     

Clinical and radiologic analysis of 13 cases of primary neuroectodermal tumors of bone

Radiographs and clinical charts were reviewed in a series of 13 cases of primary neuroectodermal bone tumors, involving 9 males and 4 females, aged from 3 to 32 years (average: 15 years). The average delay between the onset and diagnosis was 5 months. Fever and other systemic symptoms were present in 6 cases; in 4 cases a fracture was the mode of presentation. Seven patients had metastases (4 involving bone) at the time of presentation. Only one patient is still alive after 5 years. In the 10 patients who died as a direct result of the tumor, death occured on average 8 months following diagnosis if metastases were present initially, and 36 months after the diagnosis otherwise. Tumors predominantly involved the leg (7 cases), the pelvis (2 cases), and the humerus (2 cases), the involvement being both diaphyseal and metaphyseal. The radiologic appearance is that of an aggressive, poorly demarcated tumor, with cortical destruction, periosteal reaction and soft tissue invasion. Comparison with Ewing sarcoma shows little radiologic or clinical difference, except for a poorer prognosis in neuroectodermal bone tumors. Both bone tumors may have a similar neuroectodermal origin, with Ewing sarcoma representing the undifferentiated variety.     

Can parturients identify the midline during neuraxial block placement?

Study Objective

To determine whether parturients can reliably identify their midline during epidural or spinal needle insertion, and to determine whether parturient feedback helps the anesthesiologist successfully identify the midline.

Design

Survey instrument completed by anesthesiologists.

Setting

Labor and delivery unit of a university-based, tertiary-care hospital.

Measurements

Completed questionnaires were obtained for 554 of 904 (61.3%) neuraxial blocks. Data were collected on the type of neuraxial block, number of needle redirections required to identify the midline, the patient's height and weight, the patient's position during block placement, whether the patient was questioned for assistance identifying the midline, and if so, how helpful the patient was in redirecting the needle to locate the epidural or subarachnoid space.

Main Results

The anesthesiologist requested the assistance of 194 patients (35.0%) for needle location. Of those questioned, the anesthesiologist reported 128 instances (66.0%) when the patient's response was helpful in identification of the midline. Morbidly obese parturients (BMI > 35 kg/m²) were questioned more often than their non-morbidly obese counterparts (48.9% vs. 30.5%; P < 0.0005). Of those morbidly obese parturients who were questioned (n = 64), 76.6% were reported by the anesthesiologist to be helpful.

Conclusions

Most patients, including morbidly obese patients, are helpful in identifying the midline during neuraxial anesthesia.     

Comparison of PCR with blood smear and inoculation of small animals for diagnosis of Babesia microti parasitemia.

The specific diagnosis of babesiosis, which is caused by the piroplasm Babesia microti, is made by microscopic identification of the organism in Giemsa-stained thin blood smears, detection of babesial antibody in acute-and convalescent-phase sera, or identification of the organism following the injection of patient blood into laboratory animals. Although rapid diagnosis can be made with thin blood smears, parasites are often not visualized early in the course of infection. PCR is a new, rapid diagnostic technique for the detection of Babesia spp. that has not yet been systematically evaluated. We conducted a blinded study of the sensitivity, specificity, and reproducibility of the PCR-based test with patients with babesiosis and a group of asymptomatic subjects residing in a region in southern New England where babesiosis is enzootic. Among 19 patients with recent babesial illness, we found that PCR was as sensitive and specific as the use of Giemsa-stained blood smears and inoculation of hamsters. Among asymptomatic subjects, the PCR result was positive for 3 persons with recent babesial infection and was negative for 41 persons without previous babesial infection. We conclude that the B. microti PCR procedure is sufficiently sensitive, specific, and reproducible for use in the diagnosis of acute babesiosis.     

Antibody response of the mouse reservoir of Borrelia burgdorferi in nature.

To determine whether the white-footed mouse reservoir host (Peromyscus leucopus) of the agent of Lyme disease (Borrelia burgdorferi) naturally mounts an immune response against the full range of antigens expressed by this zoonotic pathogen, we analyzed the pattern of immunoreactivity of these rodents at sites in which the intensity of transmission differs. Although the incidence of seroconversion within the reservoir population relates proportionally to the density of subadult deer ticks (Ixodes dammini), seroprevalence appears constant. About a fifth as many juvenile mice recognize spirachete antigens as do adult mice. Virtually all reservoir mice in nature recognize the p20, p35.5, p39, and p58 antigens, regardless of the intensity of transmission. Seropositive mice retain reactivity to a wide range of spirochetal antigens. Few mice recognize flagellin, OspB, and OspC. Although a third of serum samples include reactivity to a 31-kDa band, this reaction is irregular and may represent an uncharacterized antigen that comigrates with OspA. Mice captured where transmission is intense recognize the same spectrum of antigens as do mice captured where vector ticks are scarce.     

Optimal voxel size for measuring global gray and white matter proton metabolite concentrations using chemical shift imaging.

Quantification of gray and white matter levels of spectroscopically visible metabolites can provide important insights into brain development and pathological conditions. Chemical shift imaging offers a gain in efficiency for estimation of global gray and white matter metabolite concentrations compared to single voxel methods. In the present study, the optimal voxel size is calculated from segmented human brain data and accompanying field maps. The optimal voxel size is found to be approximately 8 cc, but a wide range of values, 4-64 cc, can be chosen with little increase in estimated concentration error (<15%). Magn Reson Med 44:10-18, 2000.     

Spatially resolved two‐dimensional spectroscopy

A method is presented to collect spatially resolved two‐dimensional spectra on a conventional clinical scanner. Time‐varying gradients during the readout period rapidly sample data simultaneously for two spatial and two spectral dimensions. The k‐space trajectories are based on spiral paths that make efficient use of the gradient hardware. A gridding algorithm is used for reconstruction. With the spiral‐based readout gradients, current single‐voxel two‐dimensional techniques can be extended to spatially resolved volumetric acquisitions. The method is demonstrated with a two‐dimensional J‐resolved acquisition of a phantom with separate compartments of lactic acid and ethyl alcohol in water. Data were acquired with a spatial resolution of 18 × 18 pixels over a 24 cm field of view, 400 Hz spectral bandwidth in the chemical shift dimension with a 3.8 Hz resolution, and 50 Hz spectral bandwidth in the second frequency dimension with a 1.56 Hz resolution. Magn Reson Med 41:8‐12, 1999. © 1999 Wiley‐Liss, Inc.     

Neurochemical deficits in the cerebellar vermis in child offspring of parents with bipolar disorder

Singh MK, Spielman D, Libby A, Adams E, Acquaye T, Howe M, Kelley R, Reiss A, Chang KD. Neurochemical deficits in the cerebellar vermis in child offspring of parents with bipolar disorder.
Bipolar Disord 2011: 13: 189–197. © 2011 The Authors.
Journal compilation © 2011 John Wiley & Sons A/S. Objectives: We aimed to compare concentrations of N‐acetyl aspartate, myo‐inositol, and other neurometabolites in the cerebellar vermis of offspring at risk for bipolar disorder (BD) and healthy controls to examine whether changes in these neuronal metabolite concentrations occur in at‐risk offspring prior to the onset of mania. Methods: A total of 22 children and adolescents aged 9–17 years with a familial risk for bipolar I or II disorder [at‐risk offspring with non‐bipolar I disorder mood symptoms (AR)], and 25 healthy controls (HC) were examined using proton magnetic resonance spectroscopy at 3T to study metabolite concentrations in an 8‐cc voxel in the cerebellar vermis. Results: Decreased myo‐inositol and choline concentrations in the vermis were seen in the AR group compared to HC (p < 0.01). Conclusions: Decreased cellular metabolism and interference with second messenger pathways may be present in the cerebellar vermis in youth at risk for BD as evident by decreased myo‐inositol and choline concentrations in this region. These results may be limited by a cross‐sectional design, co‐occurring diagnoses, and medication exposure. Longitudinal studies are necessary to determine whether early neurochemical changes can predict the development of mania. Improved methods for identifying children with certain neurochemical vulnerabilities may inform preventive and early intervention strategies prior to the onset of mania.     

Analyses of volatile organic compounds from human skin

Background Human skin emits a variety of volatile metabolites, many of them odorous. Much previous work has focused upon chemical structure and biogenesis of metabolites produced in the axillae (underarms), which are a primary source of human body odour. Nonaxillary skin also harbours volatile metabolites, possibly with different biological origins than axillary odorants. Objectives To take inventory of the volatile organic compounds (VOCs) from the upper back and forearm skin, and assess their relative quantitative variation across 25 healthy subjects. Methods Two complementary sampling techniques were used to obtain comprehensive VOC profiles, viz., solid‐phase microextraction and solvent extraction. Analyses were performed using both gas chromatography/mass spectrometry and gas chromatography with flame photometric detection. Results Nearly 100 compounds were identified, some of which varied with age. The VOC profiles of the upper back and forearm within a subject were, for the most part, similar, although there were notable differences. Conclusions The natural variation in nonaxillary skin odorants described in this study provides a baseline of compounds we have identified from both endogenous and exogenous sources. Although complex, the profiles of volatile constituents suggest that the two body locations share a considerable number of compounds, but both quantitative and qualitative differences are present. In addition, quantitative changes due to ageing are also present. These data may provide future investigators of skin VOCs with a baseline against which any abnormalities can be viewed in searching for biomarkers of skin diseases.