Optimal intensity for respiratory muscle endurance training in patients with spinal cord injury.

OBJECTIVE: Respiratory muscle endurance of able-bodied persons, assessed by normocapnic hyperpnoea at 70% of their maximal voluntary ventilation, usually ranges from 10 to 20 minutes. The aim of this study was to determine the level of ventilation that patients with paraplegia and tetraplegia can sustain for 10-20 minutes to later be used as the guideline for respiratory muscle endurance training. DESIGN: Pilot study; cross-over setting. SUBJECTS: Two groups, 8 patients with paraplegia and 6 with tetraplegia. METHODS: Respiratory muscle endurance tests were performed at 3 different intensities of normocapnic hyperpnoea, i.e. 20%, 40% and 60% maximal voluntary ventilation. Subjects performed partial re-breathing from a bag to assure normocapnia. Respiratory endurance was separately analysed for patients with paraplegia and tetraplegia. RESULTS: Mean respiratory endurance times were 46.0, 18.9 and 4.2 minutes at 20%, 40% and 60% maximal voluntary ventilation in patients with tetraplegia and 51.8, 38.8 and 12.2 minutes in patients with paraplegia. The duration differed significantly at 60% maximal voluntary ventilation between the groups. CONCLUSION: Minute ventilation to perform respiratory muscle endurance training can be set at around 40% of maximal voluntary ventilation for patients with tetraplegia and around 60% of maximal voluntary ventilation for patients with paraplegia, as these levels can be sustained for 10-20 minutes.     

Deprivation of parenting disrupts development of homeostatic and reward systems in marmoset monkey offspring.

BACKGROUND: Early environment is a major determinant of long-term mental health, evidenced by the relationship between early-life neglect or abuse and chronically increased vulnerability to developmental psychopathology, including major depressive disorder (MDD). Animal studies can increase understanding of environmentally mediated causal risk processes. We describe how daily deprivation of biological parenting in primate infants disrupts development of homeostatic and reward systems central to MDD. METHODS: Nine breeding pairs of marmoset monkeys provided control twins (CON) and early-deprived twins (ED); the latter were socially isolated for 30-120 min/day on days 2-28. During the first year of life, basal urinary norepinephrine (NE) titers and cardiophysiologic activity were measured. At the end of year 1 (adolescence), automated neuropsychologic tests were conducted to measure responsiveness to changes in stimulus-reward association (simple/reversed visual discrimination learning) and to reward per se (progressive ratio [PR] reinforcement schedule). RESULTS: The ED monkeys exhibited increased basal urinary NE titers and increased systolic blood pressure relative to CON siblings. The ED monkeys required more sessions to reinstate stimulus-oriented behavior following reversal, suggesting increased vulnerability to perceived loss of environmental control; ED monkeys also performed less PR operant responses, indicating that reward was less of an incentive and that they were mildly anhedonic relative to CON. CONCLUSIONS: In marmoset monkeys, neglect-like manipulation of ED leads to chronic changes in homeostatic systems, similar to those in children and adolescents exposed to early-life adversity and in MDD, and to responses to environmental stimuli similar to those that characterize MDD.     

Nitrogen dioxide exposures inside ice skating rinks.

OBJECTIVES. The common operation of fuel-powered resurfacing equipment in enclosed ice skating rinks has the potential for producing high concentrations of carbon monoxide and nitrogen dioxide. Exposures to these gaseous combustion products may adversely affect the health of those inside the rink. Little information is available on pollutant concentrations under normal operating conditions. METHODS. One-week average nitrogen dioxide concentrations in 70 northeastern US rinks were measured with passive samplers during normal winter season conditions. RESULTS. The median nitrogen dioxide level inside rinks was 180 ppb, more than 10 times higher than the median outdoor concentration. One-week average nitrogen dioxide concentrations above 1000 ppb were measured in 10% of the rinks. CONCLUSIONS. Considering that short-term peak concentrations were likely to have reached two to five times the measured 1-week averages, our results suggest that nitrogen dioxide levels were well above short-term air quality guidelines and constitute a public health concern of considerable magnitude.     

Needle tract recurrences after closed biopsy for sarcoma: Three cases and review of the literature

Background: Percutaneous closed needle biopsy of musculoskeletal neoplasms has gained in popularity. However, it remains controversial whether or not to resect the needle tract for fear of a local recurrence. A single published case report exists, noting the lone tract recurrence of an extremity skeletal osteosarcoma. Methods: We report on three additional individuals who demonstrated that tract local recurrences may occur after a closed needle biopsy for nonosteosarcoma, nonextremity sarcomas. For perspective, the world literature is reviewed to identify tract recurrences for other malignancies and the results of needle biopsy in musculoskeletal neoplasms. Results: Eighty-nine percent of needle tract local recurrences occur when carcinomas are subjected to biopsy, as reported in the literature. Forty-seven cases since 1950 are described representing essentially all tumor types. The nature of musculoskeletal neoplasms makes closed biopsy more difficult than for softer, more homogeneous, and easier to access neoplasms. Conclusions: Local recurrences of sarcoma may occur in closed needle biopsy tracts. Strong consideration should be given to open biopsy and tract resection.     

Chromosomal localization of three genes coamplified in the multidrug-resistant CHRC5 Chinese hamster ovary cell line

At least five gene classes are amplified in the multidrug-resistant CHO cell line CHRC5. Protein products have been identified for two classes; class 2 codes for the large membrane P-glycoprotein, whereas class 4 encodes the small cytoplasmic calcium-binding protein sorcin (V19). By DNA analysis we have shown previously that these five genes are linked in two groups: class 1 + 2 + 3; and class 4 + 5. By use of in situ hybridization with complementary DNAs derived from the resistant cell line we demonstrate here that genes from both linkage groups are amplified and situated together in each of two different chromosomal regions of the resistant Chinese hamster cell line. The positions of the amplicons correspond to cytogenetically identified homogeneously staining regions in an altered 7q+ chromosome and in a rearranged Z-7 [t(3;4)] chromosome. The native genes were mapped both in the CHRC5 line and in a normal diploid Chinese hamster cell strain, CHNF 86. We confirm the position of the class 2 gene on 1q26 and we show that class 4 and 5 genes are located in the same region of 1q. We conclude that the gene classes 2, 4, and 5 are closely juxtaposed in the normal Chinese hamster genome and comprise one amplicon in resistant cells. Our results are compatible with the hypothesis that multidrug resistance is due to overexpression of P-glycoprotein genes and that the other genes amplified in the CHRC5 line are coamplified because they happen to lie close to the P-glycoprotein genes.     

The CCR5Delta32 allele is associated with reduced liver inflammation in hepatitis C virus infection.

CCR5Delta32 is a deletion mutation in the chemokine receptor CCR5. Liver inflammatory activity was found to be significantly reduced (P = 0.005) in Jewish Israeli patients infected with the hepatitis C virus (HCV) carrying the CCR5Delta32 allele. The CCR5Delta32 allele does not alter susceptibility to HCV infection; however, it may play a role in the progression and outcome of the disease.     

Clonidine in the treatment of brainstem spasticity. Case report.

This report describes a patient who developed spasticity after a medullary infarct. No improvement in her spasticity was achieved by baclofen therapy and the side effects of the drug necessitated its gradual withdrawal. Recent reports of the success of clonidine in the management of spasticity due to spinal cord injury prompted an attempt at clonidine therapy. When clonidine therapy was initiated, the patient responded rapidly with both subjective and objective improvements in her spasticity. This case suggests a potential role for clonidine in the treatment of spasticity resulting from brainstem infarction.     

Environmental tobacco smoke concentrations in no-smoking and smoking sections of restaurants.

To characterize the effectiveness of a local ordinance that restricts smoking in restaurants to one third of the seating area, this study made simultaneous measurements of two markers of environmental tobacco smoke, respirable suspended particles and nicotine, in the smoking and no-smoking sections of seven restaurants. The mean concentrations of respirable suspended particles and nicotine were 40% and 65% lower, respectively, in the no-smoking than in the smoking sections, indicating substantial but not complete protection against exposure.     

Receptive field scatter,topography and map variability in different layers of the hindpaw representation of rat somatosensory cortex

We recorded neurons extracellularly in layers II/III, IV, and V of the hindpaw representation of primary somatosensory cortex in anesthetized rats and studied laminar features of receptive fields (RFs) and representational maps. On average, RFs were smallest in layer IV and largest in layer V; however, for individual penetrations we found substantial deviations from this rule. Within the hindpaw representation, a distinct rostrocaudal gradient of RF size was present in all layers. While layer V RFs were generally largest independent of this gradient, layer IV RFs recorded caudally representing the proximal portions of the paw were larger than layer II/III RFs recorded rostrally representing the digits. The individual scatter of the locations of RFs across laminar groups was in the range of several millimeters, corresponding to about 25% of the average RF diameter. The cutaneous representations of the hindpaw in extragranular layers were confined to the areal extent defined by responsive sites in layer IV. Comparison between RFs determined quantitatively and by handplotting showed a reliable correspondence. Repeated measurements of RFs revealed spontaneous fluctuations of RF size of no more than 5% of the initial condition over an observation period of several hours. The topography and variability of cortical maps of the hindpaw representation were studied with a quantitative interpolation method taking into account the geometric centers of RFs and the corresponding cortical recording sites. On average, the overall topography in terms of preservation of neighborhood relations was present in all layers, although some individual maps showed severe distortions of topography. Factors contributing to map variability were overall position of the representation on the cortical surface, internal topography and spatial extent. Interindividual variability of map layout was always highest in the digit representations. Local topographic orderliness was lowest in layer V, but comparable in layers II/III and IV. Within layer IV, the lowest orderliness was observed in the digit representations. Our data emphasize a substantial variability of RF size, overlap and position across layers and within layers. At the level of representational maps, we found a similar degree of variability that often co-varied across layers, with little evidence for significant layer specificity. Laminar differences are likely to arise from the specific input-output pattern, layer-specific cell types and the connectivity between different layers. Our findings emphasizing similarities in the variability across layers support the notion of tightly coupled columnar interactions between different layers.