Repeated treadmill walks affect physiologic responses in children with cerebral palsy

PURPOSE: To determine whether physiologic responses during treadmill walking in children with cerebral palsy (CP) are affected by repeated walking bouts on different days, and whether effects are different at different speeds. METHODS: Three girls and five boys (9.2-15.7 yr, 23.3-64.4 kg) with mild CP received 12-15 min of treadmill walking practice and had their fastest walking speed (FWS) determined during an introductory visit. During each of three subsequent visits (day 1, day 2, day 3), subjects walked for 3 min at 60, 75, and 90% FWS. Resting physiologic measures were taken on day 1. RESULTS: From day 1 to day 3, net ventilation ([OV0312]E), and net heart rate (HR) at 90% FWS decreased by 3.6 L.min-1 and 8 beats.min-1, respectively. There were no differences between day 1 and day 2 or day 1 and day 3 for any other physiologic variable at any speed. Day 3 was less than day 2 for net HR (60% FWS) and, independent of speed, net [OV0312]O2 (per kilogram of body mass and per stride) and net energy expenditure (kJ.min-1). Between-day reliability (R) of physiologic responses was > or = 0.95, except respiratory rate (R = 0.75). Intrasubject, between-day variability for the [OV0312]O2 measures was 7.6-12.9%. CONCLUSION: Because there were no day 1 to day 3 reductions in metabolic variables, day 1 to day 3 reductions at 90% FWS in net HR may reflect decreased emotional stress over time and reductions in net [OV0312]E, an uncoupling of [OV0312]O2 and [OV0312]E. Despite between-day differences, reliable net physiologic and stable net metabolic variables may be collected in subjects with mild CP after one treadmill walking practice session.     

Use of a cold cathode for percutaneous stimulation of human plantarflexor muscles

Prolonged, supramaximal stimulation of the soleus muscle is painful to humans. A method is proposed whereby percutaneous, supramaximal stimulation is possible using a cold cathode. Cooling the skin exposed to the stimulating current results in a sufficient anaesthesia of nociceptive cutaneous afferent nerves. This occurs without concomitant cooling of the muscle mass deep to the skin and subcutaneous tissue. Electronic Publication     

Trends of probable post-traumatic stress disorder in New York City after the September 11 terrorist attacks

The authors investigated trends in probable post-traumatic stress disorder (PTSD) prevalence in the general population of New York City in the first 6 months after the September 11 terrorist attacks. Three random digit dialing telephone surveys of adults in progressively larger portions of the New York City metropolitan area were conducted 1 month, 4 months, and 6 months after September 11, 2001. A total of 1,008, 2,001, and 2,752 demographically representative adults were recruited in the three surveys, respectively. The current prevalence of probable PTSD related to the September 11 attacks in Manhattan declined from 7.5% (95% confidence interval: 5.7, 9.3) 1 month after September 11 to 0.6% (95% confidence interval: 0.3, 0.9) 6 months after September 11. Although the prevalence of PTSD symptoms was consistently higher among persons who were more directly affected by the attacks, a substantial number of persons who were not directly affected by the attacks also met criteria for probable PTSD. These data suggest a rapid resolution of most of the probable PTSD symptoms in the general population of New York City in the first 6 months after the attacks. The psychological consequences of a large-scale disaster in a densely populated urban area may extend beyond persons directly affected by the disaster to persons in the general population.     

Depletion and sizes of motor units in spinal muscular atrophy

Motor unit number estimation (MUNE) was applied to the biceps brachii muscles of 13 young patients (age 5--24 years) with spinal muscular atrophy (SMA) and the results compared with those of healthy control subjects matched for age and gender. In the SMA patients, all motor unit (MU) estimates fell below the control range, and there was good correspondence between the values for the two arms in the same subject. No correlation could be found between the MUNEs and the severity of the weakness. This unexpected result was attributed to the presence of small and normal-sized MUs in the muscles of patients, in addition to MUs that appeared to be considerably enlarged. The threefold mean increase in MU potential size was insufficient to compensate for the MU loss. In addition, the study confirmed that there are, on average, approximately 130 MUs in the healthy biceps brachii muscle.     

Local anesthetics potentiate nitric oxide synthase type 2 expression in rat glial cells

Expression of the calcium-independent nitric oxide synthase (NOS2) contributes to damage in neurologic disease and trauma. The effects of local anesthetics on NOS2 expression have not been examined. The authors tested the effects of four local anesthetics on the expression of NOS2 in immunostimulated rat C6 glioma cells. Incubation with local anesthetics alone did not induce nitrite accumulation; however, the nitrite production induced by stimulation with bacterial endotoxin lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma) was increased in a dose-dependent manner by bupivacaine (maximal 3-fold at 360 microM), tetracaine (maximal 7-fold at 360 microM), and lidocaine at higher doses (5-fold increase at 3.3 mM). Significant increases in nitrite production were observed in concentrations of bupivacaine or tetracaine as low as 120 microM, which correspond to 30 microg/mL (.003% weight/volume). In contrast, ropivacaine had little effect on nitrite production (160% of control values) and only at the highest concentration (3.3 mM, corresponding to 890 microg/mL or 0.089% w/v) tested. Increased nitrite production was not caused by cytotoxic effects of the drugs used, as assessed by release of intracellular lactate dehydrogenase. Increased nitrite production was accompanied by increased NOS2 catalytic activity, steady state mRNA levels, and promoter activation. These results demonstrate that submillimolar doses of two commonly used local anesthetics can increase glial NOS2 expression.     

Feto-fetal transfusion syndrome

Out of 42 pairs of liveborn monochorial twins there were 32 pairs with vascular anastomoses. Of these, 11 pairs had feto-fetal transfusion syndrome. There were another 8 pairs of stillborn twin fetuses with vascular communications and in these chronic feto-fetal transfusion syndrome might have resulted in intrauterine death.     

Socioeconomic mobility in adulthood and cardiovascular disease mortality

PurposeLife course models suggest that socioeconomic mobility is associated with decreased cardiovascular disease (CVD) mortality risk. We examined adult socioeconomic mobility measured by household income in relation to CVD mortality risk among older adults.MethodsData from 2691 (n_men = 1157; n_women = 1534) Alameda County Study respondents in 1994 were used in these analyses. Latent growth curve models were used to identify income patterns from 1965 to 1994.ResultsIncome patterns were categorized as consistently low, moderately low, increasing, and high. Bivariate models showed that membership in the increasing compared with high pattern was associated with decreased hazards of CVD mortality (hazard ratio, 0.15; 95% confidence interval [CI], 0.04–0.53). Controlling for age, race/ethnicity, marital status, and gender, respondents in the consistently low (HR, 2.1; 95% CI, 1.5–3.1) and high pattern (HR, 2.2; 95% CI, 1.1–4.2) had increased hazards of CVD mortality than those in the moderately low income group.ConclusionsPatterns of association were consistent with social mobility models of socioeconomic position, indicating lower CVD mortality risk for those with increasing or higher incomes. Future work should continue to investigate measures that capture the variation in social mobility over the life course, and how these patterns shape chronic disease risk in later life.     

Are doctors and nurses associated with coverage of essential health services in developing countries? A cross-sectional study

Background  

There is broad policy consensus that a shortage of doctors and nurses is a key constraint to increasing utilization of essential health services important for achieving the health Millennium Development Goals. However there is limited research on the quantitative links between health workers and service coverage rates. We examined the relationship between doctor and nurse concentrations and utilization rates of five essential health services in developing countries.     

Hematological changes associated with marathon running

Coulter profiles with differential white cell counts, serum ferritin, and haptoglobin levels were determined in venous blood samples obtained from 90 males (M) and 25 females (F) immediately before and after completion of a competitive marathon (42.2 km) race. In an additional 20 male runners, the same measurements were performed serially during the 24 h following their completion of the race. In the pre-race samples from 90 M and 25 F, hypoferritinemia was present in 4/22 M and 1 F found to be mildly anemic. Neutropenia was detected in 4 M and 3 F and mild thrombocytopenia in 2 M. Haptoglobin levels were normal in all the female runners but reduced (less than 0.3 g/l) in 6 M. All post-race samples (88 M and 25 F) were characterized by a reactive neutrophilia and thrombocytosis including those with pre-race neutropenia or thrombocytopenia. An unexpected and incompletely explained sex difference in packed cell volume (PCV) response was observed. In males, the mean PCV increased from 0.425 +/- 0.021 to 0.444 +/- 0.028 (P less than 0.0001) whereas in females it decreased from 0.437 +/- 0.029 to 0.423 +/- 0.036 (P less than 0.05). In the post-race samples, anhaptoglobinemia was found in 13/88 M and 4/25 F. In the 20 male runners studied serially for 24 h after the race, the major changes involved a progressive increase in mean plasma volume (17.4% +/- 12.2% at 24 h) compared with the pre-race value, a progressive and significant increase in MCH and MCHC probably indicating a loss in red cell water and the gradual reversion of the reactive neutrophilia and thrombocytosis to basal levels.