Reversal of granulocyte adherence to nylon fibers using local anesthetic agents: possible application to filtration leukapheresis

The effects of the cationic anesthetic agents tetracaine and lidocaine on granulocyte function, morphology, and adherence to nylon fibers were studied in an attempt to improve current methods of granulocyte collection by filtration leukapheresis (FL). When dissolved in acid- citrate-dextrose (ACD) plasma, these drugs significantly increased granulocyte elution from the fibers in a dose-related fashion. Granulocytes exposed to tetracaine and lidocaine remained more than 95% viable, retained normal bactericidal capacity after the drugs were washed from the cells, and had preserved membrane integrity, as evidenced by the normal ultrastructural appearance of tetracaine- exposed cells and an absence of leakage of lysozyme or lactic dehydrogenase. Granulocytes eluted with the anesthetic agents were rounded in shape with a reduction in the number of filopodial cytoplasmic projections and a relative absence of cytoplasmic vacuolization when compared to granulocytes eluted with ACD plasma alone. Dose-related inhibition of phagocytosis and adherence, which was largely reversible after washing the granulocytes, was noted. Greater than 95% of the lidocaine could be removed from the eluate with a single centrifugation and resuspension, indicating that granulocytes prepared by FL with anesthetic-enhanced elution could be potentially transfusable.     

Platelets inhibit the induction of nitric oxide synthesis by interleukin-1 beta in vascular smooth muscle cells

We have investigated the role of platelets in regulating the hemostatic and vasomotor properties of vascular smooth muscle. Experiments were performed to examine the effect of the releasate from activated platelets on the production of nitric oxide from interleukin-1 beta (IL- 1 beta)-treated cultured rat aortic smooth muscle cells. Treatment of vascular smooth muscle cells with IL-1 beta resulted in significant accumulation of nitrite in the culture media and in marked elevation of intracellular cyclic guanosine monophosphate (GMP) levels. The releasate from collagen-aggregated platelets blocked the IL-1 beta- mediated production of nitrite and the accumulation of cyclic GMP in smooth muscle cells in a platelet number-dependent manner. In functional assays, the perfusates from columns containing IL-1 beta- treated smooth muscle cells relaxed detector blood vessels without endothelium and the addition of IL-1 beta-treated smooth muscle cells to suspensions of platelets inhibited their thrombin-induced aggregation. The simultaneous treatment of smooth muscle cells with IL- 1 beta and the platelet releasate abolished both the vasorelaxing activities of the perfusates and the inhibition of platelet aggregation. Platelet releasates treated with a neutralizing antibody to platelet-derived growth factor (PDGF) failed to block IL-1 beta- induced nitric oxide production by the smooth muscle cells, as measured by both biochemical and functional assays. The platelet releasate from a patient with gray platelet syndrome likewise failed to block IL-1 beta-induced nitrite release by smooth muscle cells. These results demonstrate that platelets downregulate the production of nitric oxide by IL-1 beta-treated vascular smooth muscle cells through the release of PDGF. This effect may represent a novel mechanism by which platelets regulate vasomotor tone and thrombus formation at sites of vascular injury.     

The Effect of Type of Femoral Component Fixation on Mortality and Morbidity after Hip Hemiarthroplasty: A Systematic Review and Meta-Analysis

HSS Journal ® - Hip hemiarthroplasty is a well-established treatment of displaced femoral neck fracture, although debate exists over whether cemented or uncemented fixation is superior....     

Biological risk indicators for recurrent non-specific low back pain in adolescents

Objectives: A matched case-control study was carried out to evaluate biological risk indicators for recurrent non-specific low back pain in adolescents.

Methods: Adolescents with recurrent non-specific low back pain (symptomatic; n = 28; mean (SD) age 14.9 (0.7) years) and matched controls (asymptomatic; n = 28; age 14.9 (0.7) years) with no history of non-specific low back pain participated. Measures of stature, mass, sitting height, sexual maturity (Tanner self assessment), lateral flexion of the spine, lumbar sagittal plane mobility (modified Schöber), hip range of motion (Leighton flexometer), back and hamstring flexibility (sit and reach), and trunk muscle endurance (number of sit ups) were performed using standardised procedures with established reliability. Backward stepwise logistic regression analysis was performed, with the presence/absence of recurrent low back pain as the dependent variable and the biological measures as the independent variables.

Results: Hip range of motion, trunk muscle endurance, lumbar sagittal plane mobility, and lateral flexion of the spine were identified as significant risk indicators of recurrent low back pain (p<0.05). Follow up analysis indicated that symptomatic subjects had significantly reduced lateral flexion of the spine, lumbar sagittal plane mobility, and trunk muscle endurance (p<0.05).

Conclusions: Hip range of motion, abdominal muscle endurance, lumbar flexibility, and lateral flexion of the spine were risk indicators for recurrent non-specific low back pain in a group of adolescents. These risk indicators identify the potential for exercise as a primary or secondary prevention method.

     

Angiotensin‐converting enzyme inhibition increases glucose‐induced insulin secretion in response to acute restraint

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Predictors of increased body mass index in Chinese children

A longitudinal study design was used to examine factors related to change of body mass index (BMI) over a 1-year period in 307 Chinese children, aged 7 and 8 years, in Taiwan. Standardized instruments were used to measure the children's food intake, physical activity/inactivity, and physical fitness, as well as maternal BMI. Results suggested that a high baseline BMI, poor aerobic capacity, and a high maternal BMI were significantly correlated with increased BMI at 12 months' follow-up. A higher baseline BMI, an overweight mother, increased television viewing and computer time, and poorer aerobic capacity were identified as predictors for weight gain in children (F=207.67; P<.001; adjusted R(2)=0.752). These findings suggest that health care providers need to include the family in children's health care visits and incorporate an assessment of maternal weight status and children's BMI status, activity levels, and aerobic capacity into patient care and education.     

GROWTH HORMONE ATTENUATES MYOCARDIAL FIBROSIS IN RATS WITH CHRONIC PRESSURE OVERLOAD-INDUCED LEFT VENTRICULAR HYPERTROPHY

• 1 The role of growth hormone (GH) in cardiac remodelling and function in chronic and persistent pressure overload‐induced left ventricular hypertrophy has not been defined. The aim of the present study was to assess short‐term GH treatment on left ventricular function and remodelling in rats with chronic pressure overload‐induced hypertrophy.
• 2 Twenty‐six weeks after induction of ascending aortic stenosis (AAS), rats were treated with daily subcutaneous injections of recombinant human GH (1 mg/kg per day; AAS‐GH group) or saline (AAS‐P group) for 14 days. Sham‐operated animals served as controls. Left ventricular function was assessed by echocardiography before and after GH treatment. Myocardial fibrosis was evaluated by histological analysis.
• 3 Before GH treatment, AAS rats presented similar left ventricular function and structure. Treatment of rats with GH after the AAS procedure did not change bodyweight or heart weight, both of which were higher in the AAS groups than in the controls. After GH treatment, posterior wall shortening velocity (PWSV) was lower in the AAS‐P group than in the control group. However, in the AAS‐GH group, PWSV was between that in the control and AAS‐P groups and did not differ significantly from either group. Fractional collagen (% of total area) was significantly higher in the AAS‐P and AAS‐GH groups compared with control (10.34 ± 1.29, 4.44 ± 1.37 and 1.88 ± 0.88%, respectively; P < 0.05) and was higher still in the AAS‐P group compared with the AAS‐GH group.
• 4 The present study has shown that short‐term administration of GH to rats with chronic pressure overload‐induced left ventricular hypertrophy induces cardioprotection by attenuating myocardial fibrosis.