Optically driven microelectromechanical-system deformable mirror under high-frequency AC bias

A new, optically addressed deformable mirror device is demonstrated. The device consists of a pixellated metalized polymeric membrane mirror supported above an optically addressed photoconductive substrate. A conductive transparent ZnO layer is deposited on the back side of the substrate. A very high-frequency AC bias is applied between the membrane and the back electrode of the device. The membrane is deformed when the back of the device is illuminated because of impedance and bias redistribution between two cascaded impedances. We fabricated, demonstrated, and modeled the operation of this device.

Elbow deformities after fracture

Nonunion of the lateral humeral condyle,cubitus varus, cubitus valgus, and fishtail deformity represent particularly challenging problems to the upper extremity surgeon. Although closed or open reduction and pinning of supracondylar fractures of the distal humerus can restore anatomic alignment and avoid anatomic deformities in most cases, closed reduction is still a common form of treatment. In those hopefully few cases in which reduction is less than optimal, or when a good reduction is performed but subsequently lost between follow-up visits, the aforementioned deformities of the distal humerus can develop. Even when anatomic reduction is obtained and held, avascular necrosis of the trochlea may develop, leading to the so-called fishtail deformity. Although not recognized for several years, and when initially recognized, not necessarily taken seriously, fishtail deformity may be one of the more devastating deformities in that it is not correctable by traditional methods of osteotomy. Flexion contracture when present may be treated by standard release; however, when a bony block exists as a result of the shape of the fishtail, nonsurgical options exist and the patient often is left with a permanent loss of motion.

CAVEOLAE ARE NEGATIVE REGULATORS OF TRANSFORMING GROWTH FACTOR-β1 SIGNALING IN URETERAL SMOOTH MUSCLE CELLS

PURPOSE

The mechanisms underlying ureteral cell regulation are largely unknown. Previous studies have identified lipid rafts/caveolae as regulators of growth stimulatory signals in ureteral smooth muscle cells (USMCs). In this study we determined whether growth inhibitory signaling by transforming growth factor-beta1 (TGF-beta1) is also regulated by caveolae in USMC.

MATERIALS AND METHODS

Expression of components of the TGF-beta1 signaling axis in USMCs was determined by immunoblot and mRNA analyses. Growth regulatory activity of TGF-beta1 was assessed by H-thymidine incorporation. In select experiments caveolae were disrupted reversibly by cholesterol depletion and replenishment prior to TGF-beta1 treatment. TGF-beta1-responsive gene expression was evaluated using the TGF-beta1 responsive promoter-reporter construct 3TP-Lux.

RESULTS

USMCs expressed TGF-beta1, types I and II TGF-beta1 receptors, and the effector Smad-2. TGF-beta1 potently inhibited DNA synthesis in USMCs (IC50 60 pM). TGF-beta1 mediated DNA synthesis inhibition was potentiated following the disruption of caveolae by cholesterol depletion. This effect was reversible with membrane cholesterol restoration. TGF-beta1 stimulated gene activity was augmented by caveolae disruption, while caveolae reformation returned promoter activity to baseline levels.

CONCLUSIONS

TGF-beta1 is a potent growth inhibitor of USMCs and its activity can be enhanced by caveolae ablation. These findings suggest a role for TGF-beta1 in the growth regulation of normal ureteral cells and implicate caveolar membrane domains in the negative regulation of TGF-beta1 signaling. These studies may be relevant to ureteral pathologies that are characterized by smooth muscle dysplasia.

Blastocystis hominis as a cause of hypoalbuminemia and anasarca

The protozoan Blastocystis hominis has been considered nonpathogenic, but this classification has come under scrutiny in light of reports in the medical literature indicating it could be the cause of intestinal disorders and, in one case, hypoalbuminemia. Reported here is a severe case of infection with B. hominis that caused acute gastroenteritis with prolonged diarrhea, hypoalbuminemia and anasarca. The diagnosis was based on the parasitological finding, since no other pathological evidence was found. The patient responded favorably to treatment with metronidazole for 10 days. This case supports the idea that B. hominis should be considered as a cause of opportunistic infection in debilitated patients despite the controversy surrounding its pathogenicity.

Signaling through PI3K/Akt mediates stretch and PDGF-BB-dependent DNA synthesis in bladder smooth muscle cells

PURPOSE

Smooth muscle cells (SMC) of the bladder undergo hypertrophy and hyperplasia following exposure to sustained mechanical overload. Although superficial similarities in the response of the heart and bladder to hypertrophic stimuli suggest that similar molecular mechanisms may be involved, this remains to be demonstrated. In this study we compared signal transduction pathway activation in primary culture bladder SMC and cardiac myofibroblasts in response to cyclic stretch. The effects of growth factor stimulation on pathway activation in bladder SMC were also investigated.

MATERIALS AND METHODS

Primary culture rodent bladder SMC or cardiac myofibroblasts were subjected to cyclic stretch-relaxation in the absence or presence of pharmacologic inhibitors of the phosphoinositide-3-kinase, (PI3K)/Akt, extracellular signal-regulated kinase-mitogen activated protein kinase (Erk-MAPK) or the p38 stress-activated protein kinase-2 (SAPK2) pathways. In parallel experiments human bladder SMC were treated with platelet-derived growth factor-BB (PDGF-BB), heparin-binding EGF-like growth factor (HB-EGF) or fibroblast growth factor-2 (FGF-2). In each case the extent of DNA synthesis was determined by uptake of tritiated thymidine, and activation of specific signaling intermediates was determined by immunoblot analysis using antibodies to the non-phosphorylated and phosphorylated (activated) forms of Akt, p38 and Erk1/2.

RESULTS

Akt and p38 were rapidly phosphorylated in stretched bladder SMC and cardiac myofibroblasts, and stretch-induced DNA synthesis in these cells was ablated with inhibitors of PI3K or p38 but not Erk-MAPK. Similarly, PDGF-BB up-regulated DNA synthesis in bladder SMC in a p38 and Akt-dependent manner.

CONCLUSIONS

We conclude that distinct stimuli, such as mechanical stretch and PDGF-BB, promote DNA synthesis in bladder SMC through shared downstream signaling pathways. Furthermore, phenotypically similar cells from the bladder and heart show comparable pathway activation in response to stretch. These findings suggest that similar molecular mechanisms underlie the altered growth responses of the bladder and heart to mechanical overload. This study also provides the first report of Akt activation in bladder SMC and suggests that Akt, consistent with its pivotal role in cardiac hypertrophy, may also be a key regulator of remodeling in the SMC compartment of the bladder exposed to hypertrophic/hyperplastic stimuli in vivo.

Platelet derived growth factor-BB is a potent mitogen for rat ureteral and human bladder smooth muscle cells: dependence on lipid rafts for cell signaling

PURPOSE

Fibromuscular tissues of the detrusor/bladder body (B), trigone (T) and ureter (U) display distinct patterns of tissue remodeling in pathologic contexts, however the mechanisms underlying these observations are unknown. In this study we asked whether B, T and U smooth muscle cells (SMC) respond to several SMC growth factors and explored the role of caveolae/lipid raft membrane microdomains in signaling by one of these factors, PDGF-BB.

MATERIALS AND METHODS

SMC were isolated and cultured from B, T and U from newborn rats and from human bladder detrusor. Responses to growth factors were assessed by cell proliferation, DNA synthesis, and immunoblot methods. Cholesterol was depleted from cell membranes in select experiments using cyclodextrin and the cholesterol synthesis inhibitor lovastatin. High-affinity PDGF receptor (PDGFR) sites were measured by 125I-PDGF-BB binding assay.

RESULTS

PDGF-BB increased DNA synthesis rate in U and T SMC, with U SMC being highly responsive; in contrast, B SMC did not respond to this growth factor. Two other mitogens, HB-EGF and FGF-2, marginally stimulated DNA synthesis in all lineages. Human detrusor (hD) SMC were also highly responsive to PDGF-BB. Differences in responses to PDGF-BB correlated with translocation of PDGFRs into the caveolae/lipid raft membrane fraction following stimulation, but not with the number of high affinity PDGF binding sites. Cholesterol depletion from cell membranes reduced the response of U and hD SMC to PDGF-BB.

CONCLUSIONS

These findings indicate that 1) PDGF-BB is likely to be a physiologically relevant stimulator of mitogenic signaling in certain types of urinary tract SMC, 2) there are significant and unanticipated regional differences in the ability of urinary tract SMC to respond to muscle mitogens, and 3) lipid raft membrane microdomains mediate, in part, the ability of urinary tract SMC to respond to PDGF-mediated signals.

Pediatric motor vehicle related injuries in the Navajo Nation: the impact of the 1988 child occupant restraint laws

BACKGROUND

Navajo motor vehicle mortality is the highest among the 12 Indian Health Service (IHS) administrative areas. In July 1988, the Navajo Nation enacted a primary enforcement safety belt use and a child restraint law.

OBJECTIVE

Assess the impact of the laws on the rate and severity of pediatric (0-19 years) motor vehicle injury resulting in hospitalizations in the Navajo Nation.

METHODS

Hospitalizations associated with motor vehicle related injury discharges were identified by International Classification of Diseases, 9th revision, CM E codes, 810-825 (.0,.1) from the Navajo IHS hospital discharge database. Age specific rates for the period before the law, 1983-88, were compared with those after enactment and enforcement, 1991-95. Severity of injury, measured by the abbreviated injury scale (AIS) score and new injury severity score (NISS), was determined with ICDMAP-90 software. Wilcoxon rank sum and chi(2) tests were used for analysis.

RESULTS

Discharge rates (SE) for motor vehicle injury (per 100 000) decreased significantly in all age groups: 0-4 years (62 (7) to 28 (4)), 5-11 years (55.3 (6) to 26 (4)), and 15-19 years (139 (14) to 68 (7)); p=0.0001. In children 0-4 years, the median AIS score decreased from 1.5 (1,3) (25th, 75th centile) to 1 (1,2), p=0.06, and the median NISS decreased from 3.5 (1,9) to 2 (1,5), p=0.07. The proportion of children with NISS scores >4 decreased significantly for the 0-4 year age group (p=0.03).

CONCLUSIONS

Concurrent with enactment of the Navajo Nation occupant and child restraint laws there was a reduction in the rate of motor vehicle related hospital discharges for children. Severity of injury declined in very young Navajo children. The effect of enactment and enforcement of this Native American child occupant restraint law may serve as an example of an effective injury control effort directed at Native American children.

Is the use of insulin lispro safe in pregnancy?

OBJECTIVE

To provide a review of the use and safety of insulin lispro during pregnancy.

METHODS

This is a review of the available literature on the use of insulin lispro in pregnancy. A MEDLINE search was performed which included published manuscripts and abstracts in the English language to June 2001.

RESULTS

The extensive search revealed that data on insulin lispro use during pregnancy are limited. Most of the reports on the use of insulin lispro during pregnancy demonstrated improvement of glycemic control, an increase in patient satisfaction, decreased hypoglycemic episodes, improved maternal and neonatal outcomes, and no deterioration in retinal status. However, there were two reports where it was suggested that there was an association with the use of insulin lispro in pregnancy and increased risk for the development of congenital anomalies and/or development or progression of diabetic retinopathy.

CONCLUSIONS

Preliminary data suggest that insulin lispro does not have adverse maternal or fetal effects during pregnancy in women with diabetes. The use of insulin lispro during pregnancy results in improved glycemic control, fewer hypoglycemic episodes, improved patient satisfaction, improved maternal and neonatal outcomes and no deterioration in retinal status. There is no evidence that the use of insulin lispro during pregnancy results in an increased rate of congenital malformations. A prospective randomized clinical trial is imperative for further evaluation of any possible association with the use of insulin lispro during pregnancy and an increased rate of congenital malformations or change in retinal status.

Spontaneous preterm delivery in the type 1 diabetic pregnancy: the role of glycemic control

OBJECTIVE

To determine the role of glycemic control in spontaneous preterm delivery in type 1 diabetic women.

METHODS

A secondary analysis of data from women enrolled in the Diabetes in Pregnancy Program prior to 20 weeks was performed. Multiple logistic regression was used to analyze the association between glycohemoglobin A1 in women with spontaneous preterm delivery (n = 53) and women who delivered at term (n = 200). Maternal demographics and obstetric outcomes were also compared between the groups.

RESULTS

Glycohemoglobin A1 levels were higher in the spontaneous preterm delivery group than the term group throughout pregnancy, reaching statistical significance after the first trimester. The last glycohemoglobin A1 prior to delivery was 8.1% in the spontaneous preterm delivery group and 7.4% in the term group (p = 0.002). Using multiple logistic regression, each 1% increase in glycohemoglobin A1 increased the risk of spontaneous preterm delivery by 37%.

CONCLUSION

Poor glycemic control is associated with an increased risk of spontaneous preterm delivery, suggesting that strict glycemic control may reduce the rate of preterm delivery in these women.

In vitro therapy with dobutamine, isoprenaline and sodium nitroprusside protects vascular smooth muscle metabolism from subarachnoid haemorrhage induced cerebral vasospasm

BACKGROUND

The cerebrospinal fluid (CSF) from subarachnoid haemorrhage (SAH) patients with cerebral vasospasm stimulates vasoconstriction and oxygen consumption in the porcine carotid artery in vitro. Stimulation of oxygen consumption has been used as an in vitro model of vasospasm to assess the relative benefits of nimodipine, isoprenaline, dobutamine, and sodium nitroprusside (SNP).

METHOD

Samples of human CSF were obtained from SAH patients and applied to de-endothelialised porcine carotid artery. Stimulation of oxygen consumption (as an in vitro marker for a stimulation of the vessels) was monitored and the effects of SNP, isoprenaline, dobutamine or nimodipine were measured.

FINDINGS

The CSF from SAH patients with evidence of vasospasm stimulated oxygen consumption to 0.91 +/- 0.17 (microM O2/min/g dry wt, +/- SD p < or = 0.01) and CSF from SAH patients without vasospasm did not significantly stimulate oxygen consumption 0.27 +/- 0.02, with 0.23 +/- 0.03 (microM O2/min/g dry wt) being an unstimulated rate of respiration for the porcine carotid artery. SNP, isoprenaline or dobutamine significantly (p < or = 0.01) decreased the stimulation of oxygen consumption of the porcine carotid artery whereas nimodipine did not. In a cohort of 41 SAH patients who received nimodipine alone or nimodipine and dobutamine, the in hospital mortality rate of the patients who received only nimodipine was 42% as compared to an in hospital mortality rate of 17% in the nimodipine plus dobutamine group P < or = 0.076).

INTERPRETATION

The in vivo data on the 41 patients is not statistically significant, so further studies are required to determine if the differences are important. SNP, isoprenaline and dobutamine significantly decreased oxygen consumption of the porcine carotid arteries exposed to CSF from SAH patients who had vasospasm whereas nimodipine did not. Our in vitro results suggest that these compounds require further study in patients with SAH who are at risk for vasospasm because they may have a direct benefit for the vasospastic arteries.

Overexpression of retinoic acid receptors alpha and gamma into neoplastic epidermal cells causes retinoic acid-induced growth arrest and apoptosis

Retinoids are essential for normal epidermal differentiation and are used for the prevention and treatment of numerous skin disorders and cancers in humans. In previous studies, we have shown that retinoic acid receptors (RARs) -alpha and -gamma are down-regulated during skin tumor progression. The transduction of v-ras(Ha) into primary mouse keratinocytes is sufficient to reduce both RARalpha and RARgamma protein levels as well as inhibit their transactivation functions. Our primary objective is to investigate the roles that RARalpha and RARgamma play in keratinocyte tumor cell proliferation. Through retroviral gene transduction, we overexpressed RARalpha or RARgamma into neoplastic mouse epidermal cells with down-regulated endogenous RAR proteins. Following all-trans retinoic acid (RA) treatment, RARalpha- and RARgamma-transduced cell lines exhibit a progressive, dose-dependent growth inhibition relative to the control LXSN cell lines. Further characterization of RAR-transduced cells following RA treatment reveals that both RARalpha and RARgamma cause a decrease in S-phase population, while only RARalpha causes a simultaneous G(0)/G(1) block as evidenced by reduced [(3)H]-thymidine incorporation and flow cytometric analysis of DNA content. Following RA treatment, both receptors cause an early, transient increase in the cyclin-dependent kinase inhibitor (CDKI) p21 proteins, while only RARalpha causes a simultaneous sharp, brief increase in the CDKI p16 protein. A later decrease in cyclin D(1) protein is also evident in RARalpha- and RARgamma-transduced cells. Chromatin condensation and PARP cleavage are observed in both RARalpha- and RARgamma-transduced cells indicating an RA-induced apoptosis that may be caspase dependent. Furthermore, both receptors cause a late upregulation and apparent cleavage of the squamous differentiation marker protein kinase C (PKC)-eta. These results suggest that RARalpha and RARgamma enhance growth suppression and apoptosis of neoplastic epidermal keratinocytes. This growth inhibitory effect of both retinoid receptors in neoplastic keratinocytes may be achieved through distinct as well as overlapping mechanisms of cell cycle control.

Homodyne and heterodyne imaging through a scattering medium

We introduce a novel two-dimensional (2D) homodyne and heterodyne technique for imaging objects through or embedded in a scattering medium. Our imaging approach is based on heterodyning of light with different Doppler broadenings that is scattered from objects of two different textures or from an opaque object and a textured scattering medium. We report on the initial demonstration of pulling signals out of noise for an object hidden behind a scattering medium. Enhancements of signal-to-noise ratio of the order of 50 have been achieved by use of a 2D holographic phase-sensitive detector. We also discuss the experimental feasibility of this approach for objects embedded in a scattering medium.

A side-by-side comparison of sampling methods for settled, indoor allergens

Exposure to indoor allergens is associated with asthma, but there is no standardized sampling method for measuring allergens. We compared the association of measured allergen exposure and serum-specific IgE levels and the precision of three sampling methods (Cyclone, Mighty Mite, and Readivac II) to identify a standardized sampling method for indoor allergens. A random sample of 72 children, 5 to 17 years old, with doctor-diagnosed asthma who lived in the same residence >or=2 years were enrolled. Composite, side by side floor samples were obtained with all three methods. Dust allergen concentrations and serum-specific IgE levels were measured for Der f I, Fel d I, and Bla g I. Mean allergen concentration did not differ significantly by sampling method. Cat allergen was significantly correlated with serum-specific IgE for Cyclone (P=0.003) and Mighty Mite (P=0.008), but only marginally for Readivac II (P=0.07). Dust mite allergen was significantly correlated with serum-specific IgE for Readivac II (P=0.02) and Cyclone (P=0.038), but not for Mighty Mite (P=0.12). Cockroach allergen was not correlated with serum-specific IgE for any sampling method. In multiple linear regression, cat allergen was associated with serum-specific IgE for Cyclone (P=0.007) and Mighty Mite (P=0.02), but not for Readivac II (P=0.06). In contrast, dust mite allergen was marginally associated with serum-specific IgE for Readivac II (P=0.07), but not for Mighty Mite (P=0.64) or Cyclone (P=0.27). The Cyclone and Mighty Mite were more precise than Readivac II for cat allergen, but there was no difference for dust mite allergen (P>0.05). No single method is superior for measurement of indoor allergens. In general, cat allergen collected with the Cyclone was a better predictor of serum-specific IgE levels to Fel d I, whereas dust mite allergen collected with the Readivac II was a better predictor of serum-specific IgE levels to Der f I.

Trends and patterns of playground injuries in United States children and adolescents

OBJECTIVE

To determine the prevalence, trends, and severity of injuries attributable to playground falls relative to other common unintentional mechanisms that resulted in an emergency department (ED) visit in the United States.

DESIGN AND SETTING

Data from the emergency subset of the National Hospital Ambulatory Medical Care Survey collected from 1992 to 1997 for children <20 years.

METHODS

Injury rates and 95% confidence intervals (CIs) were estimated and injury severity scores were computed.

RESULTS

There were 920551 (95% CI: 540803 to 1300299) ED visits over the 6-year study period by children and adolescents that were attributable to falls from playground equipment. The annual incidence of visits for playground injuries did not significantly decrease over the course of the study (187000 to 98000, P =.053). Injury visits for playground falls were twice as prevalent as pedestrian mechanisms, but they were less prevalent than visits for motor vehicle-- and bicycle-related injuries. A larger proportion of playground falls resulted in "moderate-to-severe" injury than did bicycle or motor vehicle injuries. Children aged 5 to 9 years had the highest number of playground falls (P =.0014). Playground falls were most likely to occur at school compared to home, public, and other locations (P =.0016).

CONCLUSIONS

Playground injury emergency visits have not significantly declined and remain a common unintentional mechanism of injury. Injury visits for playground falls were proportionally more severe than injury visits attributable to other common unintentional mechanisms. Interventions targeting schools and 5- to 9-year-old children may have the greatest impact in reducing emergency visits for playground injuries.