Changes and tracking of physical activity across seven years in Mexican-American and European-American mothers

Longitudinal changes in physical activity among 129 Mexican-American (mean age 30.8; SD = 5.6) and 97 European-American (mean age 31.2; SD = 5.4) women were studied. Two physical activity recall interviews were administered at baseline and 7 years later. At baseline, European-American women reported more vigorous leisure activity (p < .005) than Mexican-Americans, and Mexican-Americans reported more moderate work activity (p < .02) than European-Americans. Virtually all components of physical activity increased significantly over the 7 years. Pearson tracking correlations for total energy expenditure were about r = 0.30. The finding that both groups increased physical activity overtime was unexpected and was unrelated to a reduction in the number of preschool children in the homes over time.

Mitochondrial function and oxygen supply in normal and in chronically ischemic muscle: a combined 31P magnetic resonance spectroscopy and near infrared spectroscopy study in vivo

PURPOSE

We used (31)P magnetic resonance spectroscopy (MRS) and near-infrared spectroscopy (NIRS) as a means of quantifying abnormalities in calf muscle oxygenation and adenosine triphosphate (ATP) turnover in peripheral vascular disease (PVD).

METHODS

Eleven male patients with PVD (mean age, 65 years; range, 55-76 years) and nine male control subjects of similar age were observed in a case-control study in vascular outpatients. Inclusion criteria were more than 6 months' calf claudication (median, 1.5 years; range, 0.6-18 years); proven femoropopliteal or iliofemoral occlusive or stenotic disease; maximum treadmill walking distance (2 km/h, 10 degrees gradient) of 50 to 230 m (mean, 112 m); ankle-brachial pressure index of 0.8 or less during exercise (mean, 0.47; range, 0.29-0.60). Exclusion criteria included diabetes mellitus, anemia, and magnet contraindications. Simultaneous (31)P MRS and NIRS of lateral gastrocnemius was conducted during 2 to 4 minutes of voluntary 0.5 Hz isometric plantarflexion at 50% and 75% maximum voluntary contraction force (MVC), followed by 5 minutes recovery. Each subject was studied three times, and the results were combined.

RESULTS

Compared with control subjects, patients with PVD showed (1) normal muscle cross-sectional area, MVC, ATP turnover, and contractile efficiency (ATP turnover per force/area); (2) larger phosphocreatine (PCr) changes during exercise (ie, increased shortfall of oxidative ATP synthesis) and slower PCr recovery (47% +/- 7% [mean +/- SEM] decrease in functional capacity for oxidative ATP synthesis, P = .001); (3) faster deoxygenation during exercise and slower postexercise reoxygenation (59% +/- 7% decrease in rate constant, P = .0009), despite reduced oxidative ATP synthesis; (4) correlation between PCr and NIRS recovery rate constants (P < .02); and (5) correlations between smaller walking distance, slower PCr recovery, and reduced MVC (P < .001). The precision of the key measurements (rate constants and contractile efficiency) was 12% to 18% interstudy and 30% to 40% intersubject.

CONCLUSION

The primary lesion in oxygen supply dominates muscle metabolism. Reduced force-generation in patients who are affected more may protect muscle from metabolic stress.

Identification and characterisation of a developmentally regulated mammalian gene that utilises -1 programmed ribosomal frameshifting

Translational recoding of mRNA through a -1 ribosomal slippage mechanism has been observed in RNA viruses and retrotransposons of both eukaryotes and prokaryotes. Whilst this provides a potentially powerful mechanism of gene regulation, the utilization of -1 translational frameshifting in regulating mammalian gene expression has remained obscure. Here we report a mammalian gene, Edr, which provides the first example of -1 translational recoding in a eukaryotic cellular gene. In addition to bearing functional frameshift elements that mediate expression of distinct polypeptides, Edr bears both CCHC zinc-finger and putative aspartyl protease catalytic site retroviral-like motifs, indicative of a relic retroviral-like origin for Edr. These features, coupled with conservation of Edr as a single copy gene in mouse and man and striking spatio-temporal regulation of expression during embryogenesis, suggest that Edr plays a functionally important role in mammalian development.

Efficacy of in-feed tylosin phosphate for the treatment of necrotic enteritis in broiler chickens

The efficacy of tylosin phosphate for the treatment of necrotic enteritis (NE) was investigated in a floor pen study of 2,000 broiler chickens. A model in which Clostridium perfringens was administered in the feed on Days 14 to 16 was used to initiate an outbreak of NE. Treatments, allocated at the pen level in a randomized complete block design, consisted of five levels of tylosin phosphate (0, 50, 100, 200, or 300 ppm) administered in the feed on Days 15 to 22, following the identification of an outbreak of NE on Day 15. Mortality due to NE was significantly reduced (P < 0.05) for medicated birds at all dose levels of tylosin phosphate compared to unmedicated birds. Mean NE lesion scores on Day 17 were significantly reduced (P < 0.05) by all levels of tylosin treatment compared to those of unmedicated birds, decreasing linearly from 2.66 at 0 ppm to 0.38 at 100 ppm and 0 at higher doses. Tylosin at all levels provided improvement in Day 29 body weight, average daily gain, feed to gain ratio, and average daily feed intake compared to unmedicated birds. The results of this study provide evidence that tylosin phosphate, when administered in feed, is effective in the treatment of clinical outbreaks of NE in broiler chickens and suggest that the optimal dose for this purpose is 100 ppm.

Medullomyoblastoma: case report

This 7-year-old boy presented with a 2-week history of headache, nausea, vomiting, anorexia, lethargy, and unsteadiness of gait. Brain magnetic resonance imaging (MRI) revealed a cystic mass within the vermis of the cerebellum. A suboccipital craniectomy was performed to remove a tumor that contained primitive neuroectodermal cells with florid skeletal muscle differentiation. Immunohistochemical studies and electron microscopy confirmed the presence of both a primitive neuroectodermal component and rhabdomyoblastic differentiation, consistent with the diagnosis of medullomyoblastoma. This exceedingly rare tumor of the cerebellar vermis of children is characterized by two components: primitive neuroectodermal tumor cells and skeletal muscle. Although the histogenesis remains uncertain, advances in immunohistochemistry and electron microscopy suggest the origin of this tumor from a multipotential stem cell precursor.

From fertilization to gastrulation: axis formation in the mouse embryo

Although much remains unknown about how the embryonic axis is laid down in the mouse, it is now clear that reciprocal interactions between the extraembryonic and embryonic lineages establish and reinforce patterning of the embryo. At early post-implantation stages, the extraembryonic ectoderm appears to impart proximal-posterior identity to the adjacent proximal epiblast, whereas the distal visceral endoderm signals to the underlying epiblast to restrict posterior identity as it moves anteriorward. At gastrulation, the visceral endoderm is necessary for specifying anterior primitive streak derivatives, which, in turn, pattern the anterior epiblast. Polarity of these extraembryonic tissues can be traced back to the blastocyst stage, where asymmetry has been linked to the point of sperm entry at fertilization.

Functional analysis of secreted and transmembrane proteins critical to mouse development

We describe the successful application of a modified gene-trap approach, the secretory trap, to systematically analyze the functions in vivo of large numbers of genes encoding secreted and membrane proteins. Secretory-trap insertions in embryonic stem cells can be transmitted to the germ line of mice with high efficiency and effectively mutate the target gene. Of 60 insertions analyzed in mice, one-third cause recessive lethal phenotypes affecting various stages of embryonic and postnatal development. Thus, secretory-trap mutagenesis can be used for a genome-wide functional analysis of cell signaling pathways that are critical for normal mammalian development and physiology.

Nodal signalling in the epiblast patterns the early mouse embryo

Shortly after implantation the mouse embryo comprises three tissue layers. The founder tissue of the embryo proper, the epiblast, forms a radially symmetric cup of epithelial cells that grows in close apposition to the extra-embryonic ectoderm and the visceral endoderm. This simple cylindrical structure exhibits a distinct molecular pattern along its proximal-distal axis. The anterior-posterior axis of the embryo is positioned later by coordinated cell movements that rotate the pre-existing proximal-distal axis. The transforming growth factor-beta family member Nodal is known to be required for formation of the anterior-posterior axis. Here we show that signals from the epiblast are responsible for the initiation of proximal-distal polarity. Nodal acts to promote posterior cell fates in the epiblast and to maintain molecular pattern in the adjacent extra-embryonic ectoderm. Both of these functions are independent of Smad2. Moreover, Nodal signals from the epiblast also pattern the visceral endoderm by activating the Smad2-dependent pathway required for specification of anterior identity in overlying epiblast cells. Our experiments show that proximal-distal and subsequent anterior-posterior polarity of the pregastrulation embryo result from reciprocal cell-cell interactions between the epiblast and the two extra-embryonic tissues.

Magnesium sulfate in the treatment of refractory ventricular fibrillation in the prehospital setting

OBJECTIVE

To determine if magnesium sulfate (MgSO(4)) improves outcome in cardiac arrest patients initially in ventricular fibrillation (VF).

METHODS

Randomized, prospective, double blind, placebo-controlled, multicenter prehospital trial using 2 g of MgSO(4). Eligible patients were non-traumatic cardiac arrest patients (> or =18 years of age) presenting in VF. The protocol included those patients refractory to three electroshocks. Epinephrine and either 2 g of MgSO(4) or placebo (normal saline) were then administered. The primary outcome variable was return of spontaneous circulation (ROSC) in the field and a perfusing pulse on arrival at the ED. Secondary endpoints included admission to the hospital (ADMT) and hospital discharge (DISC). IRB approval was obtained at all participating centers.

RESULTS

Total 116 patients (58 MgSO(4), 58 placebo) were enrolled during the period from 4/1992 to 10/96 with 109 available. There were no significant differences between the groups in baseline characteristics and times to cardio pulmonary resuscitation (CPR), advanced life support (ALS), and first defibrillation, except for time to study drug administration. There was no significant differences in ROSC (placebo, 18.5%, and MgSO(4), 25.5%, P=0.38), ADMT (placebo rate=16.7%, MgSO(4)=16.4%, P=1.0) or DISC (placebo rate=3.7%, MgSO(4)=3.6%, P=1.0).

CONCLUSIONS

We failed to demonstrate that the administration of 2 g of MgSO(4) to prehospital cardiac arrest patients presenting in VF improves short or long term survival.

Prospective analysis of the efficacy of continuous intraoperative nerve monitoring during thyroidectomy, parathyroidectomy, and parotidectomy

OBJECTIVE

Continuous intraoperative electromyographic monitoring was prospectively performed in all parotidectomies, thyroidectomies, and parathyroidectomies over approximately 5 years to assess the efficacy of this technology.

STUDY DESIGN AND SETTING

Continuous intraoperative nerve monitoring with perioperative nerve assessment was performed. The postresection minimal stimulation level of the nerves was determined to evaluate if this level would predict nerve function postoperatively.

RESULTS

Forty-four parotidectomies and 70 thyroid/parathyroid operations were performed with 140 nerves at risk (44 facial, 96 recurrent laryngeal). The incidence of temporary facial paralysis was 15.9% (7 of 44) and the incidence of permanent paralysis was 0%. The incidence of temporary recurrent laryngeal nerve paralysis in terms of nerves at risk was 1.0% (1 of 96), and the incidence of permanent recurrent laryngeal nerve paralysis was 0%. All patients with normally functioning facial and recurrent laryngeal nerves postoperatively had minimal stimulation levels less than or equal to 0.4 mA.

CONCLUSION

Continuous intraoperative nerve monitoring was associated with extremely low rates of temporary and permanent nerve paralysis in our series of 140 nerves at risk as compared to the rates documented in the literature.

Aortic side branch embolization before endovascular aneurysm repair: incidence of type II endoleak

PURPOSE

To assess the feasibility of embolization of aortic side branches and its impact on the incidence of type II endoleak after endovascular aneurysm repair.

MATERIALS AND METHODS

Endovascular aneurysm repair was performed in 74 patients. Aortic side branch vessels were evaluated on the preoperative angiogram and computed tomography (CT) and, where embolization of lumbar and inferior mesenteric vessels was considered technically possible, this was attempted prior to endovascular repair. Follow-up CT was used to assess the presence of type II endoleak.

RESULTS

Seventy-two patients were followed up for longer than 1 month. Embolization was attempted in 25 cases, successfully in 10, with partial success in 11, and failure in four. Twenty patients with successful or partly successful preoperative embolization were discharged and followed-up. Four (20%) had demonstrable type II endoleak during follow-up, with two of these persisting at latest follow-up. Of 43 patients without previous embolization, there were 10 (23.3%) type II endoleaks during the follow-up period, four of these persisting. In cases with type II endoleak, mean sac diameter change was -0.5 mm in the cases with previous embolization and +3.1 mm without. The mean period to onset of type II endoleak was 6.9 months without, and 15.3 months with, previous embolization.

CONCLUSION

Although the cohort size is below a level that would confer significance, the trend of these findings is such as to suggest a lack of influence of aortic side branch embolization on the incidence of type II endoleak during the follow-up period.

Efficacy of narasin in the prevention of necrotic enteritis in broiler chickens

The efficacy of narasin in the control of necrotic enteritis (NE) was investigated in a floor pen study of 2000 broiler chickens using a Clostridium perfringens feed inoculum challenge model. Treatments were 1) nonmedicated, nonchallenged; 2) nonmedicated, challenged; 3) narasin, nonchallenged; 4) narasin, challenged. Narasin was administered at 70 ppm in the feed from day 0 to trial termination on day 41. Challenge inoculum contained approximately 1 x 10(8) colony-forming units CP/ml and was administered from day 14 to day 16. In the unmedicated groups, challenged birds had significantly (P < 0.05) lower mean body weight and reduced feed efficiency at day 21 and significantly (P < 0.01) higher cumulative NE mortality at day 41 compared with unchallenged. Similarly, among unmedicated birds, those challenged had a significantly (P < 0.01) higher mean NE score on day 17 and significantly (P < 0.05) higher mean huddling scores on days 15-17 than unchallenged. Among challenged birds, those fed narasin had significantly (P < 0.05) higher mean body weight and improved feed efficiency at days 21 and 41 and significantly (P < 0.01) lower cumulative NE mortality at day 41 than unmedicated. Similarly, among challenged birds, those receiving narasin had a lower mean NE score on day 17 (P > 0.05) and significantly (P < 0.05) lower huddling scores on days 16 and 17 than unmedicated. Coccidiosis lesion scores were zero for birds euthanatized from all treatment groups on day 17, suggesting that the beneficial effects of narasin were not due to prevention of coccidiosis. This study thus provides evidence that narasin is effective in the prevention of necrotic enteritis in broiler chickens.

Adjustment to cancer - coping or personal transition?

The term 'adjustment' is widely used within the psycho-oncology literature and, although it is a topic of central importance to the lived experience of people with cancer, the psychological mechanisms of adjustment have rarely been described. Rather than regarding it as the absence of psychopathology or the end-point of coping with the global threat of cancer, adjustment refers to the psychological processes that occur over time as the individual, and those in their social world, manage, learn from and adapt to the multitude of changes which have been precipitated by the illness and its treatment. However, these changes are not always for the worse: sometimes they precipitate 'healthy personal growth' in a number of areas. It is only from explicit theories of adjustment that progress can be made in understanding how and why psychological disorders so frequently develop in cancer and what steps may be taken to prevent them. This paper combines the complementary assets of coping theory and social-cognitive theory and proposes the Social-Cognitive Transition (SCT) model of adjustment, a clinical model which also accounts for the frequent reports of healthy personal growth associated with cancer.

An LDL-receptor-related protein mediates Wnt signalling in mice

Wnt genes comprise a large family of secreted polypeptides that are expressed in spatially and tissue-restricted patterns during vertebrate embryonic development. Mutational analysis in mice has shown the importance of Wnts in controlling diverse developmental processes such as patterning of the body axis, central nervous system and limbs, and the regulation of inductive events during organogenesis. Although many components of the Wnt signalling pathway have been identified, little is known about how Wnts and their cognate Frizzled receptors signal to downstream effector molecules. Here we present evidence that a new member of the low-density lipoprotein (LDL)-receptor-related protein family, LRP6 (ref. 3), is critical for Wnt signalling in mice. Embryos homozygous for an insertion mutation in the LRP6 gene exhibit developmental defects that are a striking composite of those caused by mutations in individual Wnt genes. Furthermore, we show a genetic enhancement of a Wnt mutant phenotype in mice lacking one functional copy of LRP6. Together, our results support a broad role for LRP6 in the transduction of several Wnt signals in mammals.

Graft distortion after endovascular repair of abdominal aortic aneurysm: association with sac morphology and mid-term complications

PURPOSE

To investigate the incidence, significance, and mechanism of stent-graft distortion after endovascular repair (EVR) of abdominal aortic aneurysm.

METHODS

EVR of abdominal aortic aneurysm was performed in 51 cases (49 modular, bifurcated; 2 tube). Thirty-two patients were followed for 6 or more months and had equivalent baseline and follow-up images which could be used to determine changes in graft configuration. Sac dimensions were measured using computed tomographic (CT) images and graft-related complications were recorded.

RESULTS

Amongst 32 patients evaluated on follow-up, there was graft distortion in 24. Distorted grafts were significantly (p = 0.002) associated with sac diameter reduction (mean 5 mm) and sac length reduction (mean 8.1 mm). All graft-related complications occurred in the limbs of eight distorted grafts, with a mean reduction of sac length in this group of 7.8 mm on reformatted CT images.

CONCLUSION

There was a highly significant association between graft distortion and limb complications, and reduced sac dimensions.

Should pediatric emergency care be decentralized?: an out-of-hospital destination model for critically ill children

OBJECTIVES

A time-to-initial-stabilization model for out-of-hospital destinations of critically ill children (CICs) was developed. Application of this model to assess the impact of changes in different parameters of an emergency medical services for children (EMSC) system is described.

METHODS

A computer model created a 2,500-square-mile community containing ten community hospitals (CHs) and one pediatric critical care center (PCC). Community hospitals capable of providing initial immediate stabilization of CICs were defined as emergency departments accepting pediatrics (EDAPs). Critically ill children were randomly selected in proportion to population densities across the modeled community. Time to initial stabilization (TIS) was defined as the time to arrival at either an EDAP or a PCC or time to arrival at a non-EDAP CH + travel time for a team from the PCC to the non-EDAP CH + preparation/dispatch (P/D) time. The following parameters of the model were varied and their effect on TIS was evaluated: location of CHs, location of PCC, primary destinations for CICs, percent of CHs meeting EDAP standards, out-of-hospital compliance with designated hospitals for CICs, P/D time, and ambulance speed.

RESULTS

The computer model selected 1,000 CICs in accordance with the population densities of the community. The scenario with the shortest TIS was one in which every CH achieved EDAP designation (9.8 +/- 0.5 minutes). The scenario with the longest TIS involved a model in which every CIC was transported directly to the PCC (28.6 +/- 0.33 minutes). The number of EDAPs in a community and out-of-hospital compliance with use of EDAPs produced comparable effects on the TIS. Travel speeds had a direct effect on TIS but also exaggerated inefficiencies between scenarios. The P/D time had little effect on the TIS.

CONCLUSIONS

An out-of-hospital destination model has been developed with the ability to modify multiple EMSC system variables. Application of this model demonstrates the shortest times to stabilization of critically ill children occur in systems that maximize the number of hospitals that meet EDAP standards and decentralize pediatric emergency care.

Reperfusion injury of cardiac myocytes: mechanisms, treatment, and implications for advanced practice nursing

Reperfusion injury is a major complication associated with the restoration of blood flow to previously ischemic myocardium. The deleterious effects associated with reperfusion injury result from several complex pathologic mechanisms. The complexity of these mechanisms makes development of treatment protocols difficult. The purpose of this article is to review the pathophysiology of reperfusion injury and currently indicated therapies. Implications for advanced practice nursing and areas for further research are presented.

Two liquid medium systems, mycobacteria growth indicator tube and MB redox tube, for Mycobacterium tuberculosis isolation from sputum specimens

Two manual liquid medium systems, the Mycobacteria Growth Indicator Tube (MGIT) and MB Redox tube systems, were evaluated in comparison to the radiometric BACTEC-460 semiautomated system for recovery of Mycobacterium tuberculosis from sputum specimens. The highest level of recovery, from a total of 77 culture-positive specimens, occurred with the BACTEC-460 system (92.2%), followed by the MB Redox tube (80.5%) and the MGIT (63.6%) systems. The shortest time to detection was observed also among the cultures in BACTEC-460: a mean of 12 days to a growth index (GI) of 10 and 15 days to a GI of 500. The mean times for the other systems were 16 days for the MB Redox tube system and 17.4 days for the MGIT system. The proportion of cultures grown after more than 3 weeks of incubation was only 2.8 or 8.4% in BACTEC-460 (for a GI of 10 or 500) but 17.7% in MB Redox and 22.5% in MGIT. Despite these differences in comparison to the BACTEC-460 system and some differences between the MGIT and MB Redox tube systems, either of the two manual liquid medium systems presents a reasonable alternative to the BACTEC-460 system, especially for laboratories with a limited workload, and a valuable element in the laboratory protocol, in conjunction with solid media, for obtaining rapid detection of growth from about 80% of culture-positive specimens and for better overall recovery of M. tuberculosis.

Endotension after endovascular aneurysm repair: definition, classification, and strategies for surveillance and intervention

In the ongoing evolution of a categorization system for endoleak, the authors propose the term endotension to define persistent or recurrent pressurization of the aortic aneurysm sac after endovascular repair. Endotension is evidence that the aneurysm remains at risk of rupture and should, therefore, be considered an indication for secondary intervention. Management strategies and a grading system for endotension are offered.

Storage temperatures of out-of-hospital medications

OBJECTIVES

To determine whether temperatures inside drug boxes used in the out-of-hospital setting are within the U.S. Pharmacopeia recommendations for "controlled room temperature," which is defined as a temperature maintained between 15 degrees C and 30 degrees C with a mean kinetic temperature less than 25 degrees C, and to determine whether time-temperature indicator labels can reliably monitor mean kinetic temperatures.

METHODS

Two methods were used to monitor temperatures: miniature electronic temperature recorders and color-changing time-temperature indicator labels. These were placed in drug storage boxes of advanced life support units over three summer months and two winter months.

RESULTS

In summer, the electronic recorders logged temperatures exceeding 30 degrees C in all drug storage boxes, ranging from 3% to 29% of the total time. The mean kinetic temperatures by location for the whole period ranged from 21 degrees C to 30 degrees C. In the winter, the electronic recorders logged temperatures exceeding 30 degrees C at one location 2% of the total time. There were significant temperature excursions below 15 degrees C at all locations, ranging from 16% to 90% of the total time. At one location, there were temperature readings below 0 degrees C for 9% of the total time. The mean kinetic temperatures obtained from the electronic recorders and the indicator labels differed by less than 1 degrees C.

CONCLUSIONS

This study demonstrates that out-of-hospital medications are subject to temperatures both above and below recommended storage temperatures. Time-temperature indicator labels can reliably monitor exposure to elevated temperatures.

Use of contrast-enhanced ultrasound in follow-up after endovascular aortic aneurysm repair

PURPOSE

To investigate the use of contrast-enhanced ultrasound in the detection of endoleak after endovascular repair of abdominal aortic aneurysm.

MATERIALS AND METHODS

Eighteen patients underwent follow-up on 20 occasions after endovascular aortic aneurysm repair by arterial-phase contrast-enhanced spiral computed tomography (CT). All patients had unenhanced color Doppler ultrasound and Levovist-enhanced ultrasound on the same day. The ultrasound examinations were reported in a manner that was blind to the CT results. CT was regarded as the gold standard for the purposes of the study.

RESULTS

There were three endoleaks shown by CT. Unenhanced ultrasound detected only one endoleak (sensitivity, 33%). Levovist-enhanced ultrasound detected all three endoleaks (sensitivity, 100%). Levovist-enhanced ultrasound indicated an additional six endoleaks that were not confirmed by CT (specificity, 67%; positive predictive value, 33%). In one of these six cases, the aneurysm increased in size, which indicates a likelihood of endoleak. Two of the remaining false-positive results occurred in patients known to have a distal implantation leak at completion angiography.

CONCLUSION

In this small group of patients, contrast-enhanced ultrasound appears to be a reliable screening test for endoleak. The false-positive results with enhanced ultrasound may be due to the failure of CT to detect slow flow collateral pathways. Although the number of patients in this study is small, enhanced ultrasound may be more reliable than CT in detecting endoleak.