A comparative study of treadmill tests and heel raising exercise for peripheral arterial disease

OBJECTIVES: This two part study validated a 1 min treadmill exercise test and compared this with simple heel raising exercise. METHODS: In an initial study of 24 claudicants (aged 43-79, median 63 years), ankle pressures were measured immediately after repeated treadmill exercises: for 1 min, until onset of claudication, and until maximum tolerated walking distance. Absolute value, fall and percent change in pressures were calculated. The results of this part of the study were then used as a "gold standard" for comparison with 30 s of heel raising and treadmill exercise. This second stage was performed on 21 symptomatic limbs (14 claudicants aged 42-73, median 69 years). RESULTS: Variability was least for pressures expressed as percent change after 1 min of exercise. The paired t-test revealed a significant correlation between the two methods of exercise (p < 0.05). CONCLUSION: Heel raising produced changes in ankle pressure which correlated well with those induced by treadmill exercise. We recommend the use of simple heel raising when a stress test is required to diagnose lower limb arterial insufficiency in the outpatient clinic.     

Characterization of microbial diversity by determining terminal restriction fragment length polymorphisms of genes encoding 16S rRNA

A quantitative molecular technique was developed for rapid analysis of microbial community diversity in various environments. The technique employed PCR in which one of the two primers used was fluorescently labeled at the 5' end and was used to amplify a selected region of bacterial genes encoding 16S rRNA from total community DNA. The PCR product was digested with restriction enzymes, and the fluorescently labeled terminal restriction fragment was precisely measured by using an automated DNA sequencer. Computer-simulated analysis of terminal restriction fragment length polymorphisms (T-RFLP) for 1,002 eubacterial sequences showed that with proper selection of PCR primers and restriction enzymes, 686 sequences could be PCR amplified and classified into 233 unique terminal restriction fragment lengths or "ribotypes." Using T-RFLP, we were able to distinguish all bacterial strains in a model bacterial community, and the pattern was consistent with the predicted outcome. Analysis of complex bacterial communities with T-RFLP revealed high species diversity in activated sludge, bioreactor sludge, aquifer sand, and termite guts; as many as 72 unique ribotypes were found in these communities, with 36 ribotypes observed in the termite guts. The community T-RFLP patterns were numerically analyzed and hierarchically clustered. The pattern derived from termite guts was found to be distinctly different from the patterns derived from the other three communities. Overall, our results demonstrated that T-RFLP is a powerful tool for assessing the diversity of complex bacterial communities and for rapidly comparing the community structure and diversity of different ecosystems.     

Quantitative analysis of acute axonal pathology in experimental spinal cord contusion

The major sensorimotor deficits that result from traumatic spinal cord injury (SCI) are due to loss of axons in ascending and descending pathways of the white matter (WM). Experimental treatments administered after a standardized SCI can reduce WM loss and long-term functional deficits. Thus, a significant proportion of WM loss occurs secondary to the mechanical injury and may be a target for therapeutic intervention. Presently, we know little of how and when secondary injury mechanisms operate in the WM after SCI. We therefore used a standardized rat model of clinically relevant contusion injury to examine axonal pathology over the first 24 h by light and electron microscopy. Based on qualitative evaluation of tissue at 15 min, 4 h, and 24 h after a "mild" SCI produced with a weight-drop device (10 g x 2.5 cm), we selected areas from the ventromedial WM at the lesion epicenter for quantitative analyses. We compared axon number and the proportion of axons with various axoplasmic and myelin abnormalities over time after SCI, as well as the effect of axon size on degree of pathology and loss. We found by 4 h postinjury (pi) axonal pathology was more severe than at 15 min and that a significant loss of large diameter axons had occurred; no significant additional loss of axons was seen by 24 h pi. When we compared axonal pathology after a more severe contusion (10 g x 17.5 cm), we found a greater loss of axons at 4 h. In addition, a higher proportion of the remaining axons demonstrated pathological alterations. We developed a semi-quantitative Axonal Injury Index (AII) as an overall measure of axonal pathology that was sensitive to the effects of injury severity at 4 h pi. The AII has greater statistical power than our individual measures of axonal pathology. Our results suggest that it may be possible to use the AII at 4 h pi to assess effects of potential therapeutic agents on acute axonal pathology after SCI.     

Normal human CD4+ memory T cells display broad heterogeneity in their activation threshold for cytokine synthesis

CD4+ memory T cells coordinate immune responses against viruses and other pathogens via the Ag-induced secretion of potent effector cytokines. The efficacy of these responses depends on both the overall number of pathogen-specific memory T cells and the particular array of cytokines that these cells are programmed to secrete. Here, we provide evidence that heterogeneity in Ag triggering thresholds constitutes an additional critical determinant of memory T cell function. Using a novel assay that allows single-cell detection of Ag-specific T cell cytokine production, we demonstrate that CMV-specific CD4+ memory cells from human peripheral blood display pronounced differences in their costimulatory requirements for Ag-induced triggering of IFN-gamma and IL-2 secretion, ranging from cells that trigger with little costimulation (e.g., resting APC alone) to cells requiring potent costimulation through multiple pathways (resting APC plus multiple costimulatory mAbs, or activated APC). These differences in costimulatory requirements are independent of clonal differences in TCR signaling intensity, consistent with an intrinsic activation-threshold heterogeneity that is "downstream" from the TCR. Thus, "effective" frequencies of Ag-specific CD4+ memory T cells appear to depend on the activation status of available APC, a dependence that would allow the immune system to rapidly adjust the number of functional Ag-specific memory T cells in a particular effector site according to local conditions.     

Abnormal origin of the vertebral artery from the common carotid artery

An abnormal origin of the vertebral artery from the common carotid artery (VA-CC) may occur on the right or left side with different embryonic mechanisms. We describe a patient with a double developmental anomaly, a right VA-CC and a right aortic arch. The rotation of the aortic arch caused a "twist" of the embryonic mechanisms of VA-CC and misdirected the differential diagnosis of the embryonic mechanisms at first glance. We discuss the pivotal points in differentiating the embryonic mechanisms of VA-CC.     

Medial synovial entrapment syndrome of the hip in Chinese children

BACKGROUND: "Medial synovial entrapment syndrome of the hip" is a preliminary name given by the authors to describe the topic of this paper. The authors hope to elicit the concern of clinicians and further explore the feasibility of this nomenclature for the described syndrome. METHODS: A total of 26 children with synovial disorder of the hip complained of limited motion and pain of various degrees in the hip, and a limp or refusal to bear weight. Clinical presentation, image studies, course and management were thoroughly reviewed and compared with other well-established synovial disorders of the hip. RESULTS: Twenty-two of the patients were cured by bedrest, skin traction and manipulative reduction. The remaining four patients were treated with surgery and had satisfactory results. Because of its unique clinical manifestation and the good results obtained from manipulative reduction, it is difficult to compare this condition with any other well-established disease entities. Thus, the authors suggest medial synovial entrapment syndrome of the hip (SES) as a preliminary name. CONCLUSIONS: Based on the 26 Chinese children with SES studied, the authors used clinical, anatomic and biomechanical bases for deriving this nomenclature. The similarity between transient synovitis and SES is discussed.