A review of optical pacing with infrared light.

Optical pacing (OP) uses pulsed infrared light to initiate heartbeats in electrically excitable cardiac tissues without employing exogenous agents. OP is an alternative approach to electrical pacing that may overcome some its disadvantages for some applications. In this review, we discuss the initial demonstrations, mechanisms, safety, advantages and applications of OP.

Decreased myoblast differentiation in chronic binge alcohol-administered simian immunodeficiency virus-infected male macaques: role of decreased miR-206.

Skeletal muscle stem cells play a critical role in regeneration of myofibers. We previously demonstrated that chronic binge alcohol (CBA) markedly attenuates myoblast differentiation potential and myogenic gene expression. Muscle-specific microRNAs (miRs) are implicated in regulation of myogenic genes. The aim of this study was to determine whether myoblasts isolated from asymptomatic CBA-administered simian immunodeficiency virus (SIV)-infected macaques treated with antiretroviral therapy (ART) showed similar impairments and, if so, to elucidate potential underlying mechanisms. Myoblasts were isolated from muscle at 11 mo after SIV infection from CBA/SIV macaques and from time-matched sucrose (SUC)-treated SIV-infected (SUC/SIV) animals and age-matched controls. Myoblast differentiation and myogenic gene expression were significantly decreased in myoblasts from SUC/SIV and CBA/SIV animals compared with controls. SIV and CBA decreased muscle-specific miR-206 in plasma and muscle and SIV decreased miR-206 expression in myoblasts, with no statistically significant changes in other muscle-specific miRs. These findings were associated with a significant increase in histone deacetylase 4 (HDAC4) and decrease in myogenic enhancer factor 2C (MEF2C) expression in CBA/SIV muscle. Transfection with miR-206 inhibitor decreased myotube differentiation, increased expression of HDAC4, and decreased MEF2C, suggesting a critical role of miR-206 in myogenesis. Moreover, HDAC4 was confirmed to be a direct miR-206 target. These results support a mechanistic role for decreased miR-206 in suppression of myoblast differentiation resulting from chronic alcohol and SIV infection. The parallel changes in skeletal muscle and circulating levels of miR-206 warrant studies to establish the possible use of plasma miR-206 as an indicator of impaired muscle function.

2H stable isotope analysis of human tooth enamel: a new tool for forensic human provenancing?

Stable isotope analysis of biogenic tissues such as tooth enamel and bone mineral has become a well-recognised and increasingly important method for determining the provenance of human remains, and it has been used successfully in bio-archaeological studies as well as forensic investigations. In particular, (18)O and (2)H stable isotope signatures of bone and hair, respectively, are well-established proxies of climate (temperature) and source water and are therefore considered as indicators of geographic life trajectories of animals and humans. While the methodology for (2)H analysis of human hair, fingernails, and bone collagen is currently used to determine human provenance, i.e. geographic origin and identify possible migration patterns, studies involving the analysis of (2)H in tooth enamel appear to be nonexistent in the scientific literature. Ground tooth enamel was analysed by continuous-flow isotope ratio mass spectrometry (IRMS) coupled on-line to a high-temperature conversion elemental analyser (TC/EA). An array of tooth enamel samples from archaeological and modern teeth has been analysed under different experimental conditions, and the results of this proof-of-concept study are presented. While no significant differences in (2)H abundance were noted as a result of H exchange studies or different sample preparation protocols, no significant differences or trends in measured δ(2)H-values were observed either with regard to known differences in geographical provenance. We concluded that the δ(2)H-values obtained from tooth enamel could not be used as proxy for a person's geographical origin during adolescence.

Platelet pheresis is not a useful adjunct to blood-sparing strategies in cardiac surgery.

OBJECTIVE: To examine whether specific platelet pheresis (minimal plasma harvested) would contribute toward reduced blood loss and allogenic blood requirements after cardiac surgery. DESIGN: A prospective randomized trial. SETTING: A large cardiothoracic surgical center. PARTICIPANTS: Consenting patients undergoing routine coronary artery or valve surgery (n = 54). INTERVENTIONS: Patients in the pheresis group underwent platelet pheresis in the anesthetic preparation room before general anesthesia. Pheresed platelets were stored during cardiopulmonary bypass and were returned to the patients after reversal of heparin with protamine toward the end of surgery. Control patients underwent their operations without this intervention. MEASUREMENTS AND MAIN RESULTS: Primary endpoints were blood loss and transfusion requirements. There were no differences between the 2 groups (pheresis v control: median loss, 960 mL v 1100 mL, p = 0.15; median blood transfused, 896 mL v 635 mL, p = 0.71). Secondary endpoints included analysis of platelet counts, platelet function, and surface markers. Counts remained the same after retransfusion of platelets up to 2 hours after surgery. Platelet aggregation to ristocetin was well preserved, but adenosine diphosphate caused almost no aggregation of the harvested platelets. Flow cytometry revealed the platelets to have a reduced surface density of the glycoprotein 1b receptor, and 13% of them were irreversibly activated. CONCLUSION: Platelet pheresis activates a proportion of the harvested platelets and impairs the function of the remainder; this may explain its failure to reduce postoperative blood loss and transfusion requirements.

Single molecule detection of double-stranded DNA in poly(methylmethacrylate) and polycarbonate microfluidic devices.

Single photon burst techniques were used to detect double-stranded DNA molecules in poly(methylmethacrylate) (PM MA) and polycarbonate (PC) microfluidic devices. A confocal epi-illumination detection system was constructed to monitor the fluorescence signature from single DNA molecules that were multiply labeled with the mono-intercalating dye, TOPRO-5, which possessed an absorption maximum at 765 nm allowing excitation with a solid-state diode laser and fluorescence monitoring in the near-infrared (IR). Near-IR excitation minimized autofluorescence produced from the polymer substrate, which was found to be significantly greater when excitation was provided in the visible range (488 nm). A solution containing lambda-DNA (48.5 kbp) was electrokinetically transported through the microfluidic devices at different applied voltages and solution pH values to investigate the effects of polymer substrate on the transport rate and detection efficiency of single molecular events. By applying an autocorrelation analysis to the data, we were able to obtain the molecular transit time of the individual molecules as they passed through the 7 microm laser beam. It was observed that the applied voltage for both devices affected the transport rate. However, solution pH did not alter the transit time for PM MA-based devices since the electroosmotic flow of PMMA was independent of solution pH. In addition, efforts were directed toward optimizing the sampling efficiency (number of molecules passing through the probe volume) by using either hydrodynamically focused flows from a sheath generated by electrokinetic pumping from side channels or reducing the channel width of the microfluidic device. Due to the low electroosmotic flows generated by both PMMA and PC, tight focusing of the sample stream was not possible. However, in PMMA devices, flow gating was observed by applying field strengths > -120 V/cm to the sheath flow channels. By narrowing the microchannel width, the number of molecular events detected per unit time was found to be four times higher in channels with 10 microm widths compared to those of 50 microm, indicating improved sampling efficiency for the narrower channels without significantly deteriorating detection efficiency. Attempts were made to do single molecule sizing of lambda-DNA, M13 (7.2 kbp) and pUC19 (2.7 kbp) using photon burst detection. While the average number of photons for each DNA type were different, the standard deviations were large due to the Gaussian intensity profile of the excitation beam. To demonstrate the sensitivity of single molecule analysis in the near-IR using polymer microfluidic devices, the near-IR chromophore, NN382, wasanalyzed using ourconfocal imager. A detection efficiency of 94% for single NN382 molecules was observed in the PC devices.

Nanoliter-scale sample preparation methods directly coupled to polymethylmethacrylate-based microchips and gel-filled capillaries for the analysis of oligonucleotides.

We are currently developing miniaturized, chip-based electrophoresis devices fabricated in plastics for the high-speed separation of oligonucleotides. One of the principal advantages associated with these devices is their small sample requirements, typically in the nanoliter to sub-nanoliter range. Unfortunately, most standard sample preparation protocols, especially for oligonucleotides, are done off-chip on a microliter-scale. Our work has focused on the development of capillary nanoreactors coupled to micro-separation platforms, such as micro-electrophoresis chips, for the preparation of sequencing ladders and also polymerase chain reactions (PCRs). These nanoreactors consist of fused-silica capillary tubes (10-20 cm x 20-50 microns I.D.) with fluid pumping accomplished using the electroosmotic flow generated by the tubes. These reactors were situated in fast thermal cyclers to perform cycle sequencing or PCR amplification of the DNAs. The reactors could be interfaced to either a micro-electrophoresis chips via capillary connectors micromachined in polymethylmethacrylate (PMMA) using deep X-ray etching (width 50 microns; depth 50 microns) or conventional capillary gel tubes using zero-dead volume glass unions. For our chips, they also contained an injector, separation channel (length 6 cm; width 30 microns; depth 50 microns) and a dual fiber optic, near-infrared fluorescence detector. The sequencing nanoreactor used surface immobilized templates attached to the wall via a biotin-streptavidin-biotin linkage. Sequencing tracks could be directly injected into gel-filled capillary tubes with minimal degradation in the efficiency of the separation process. The nanoreactor could also be configured to perform PCR reactions by filling the capillary tube with the PCR reagents and template. After thermal cycling, the PCR cocktail could be pooled from multiple reactors and loaded onto a slab gel or injected into a capillary tube or microchip device for fractionation.

Micromachining in plastics using X-ray lithography for the fabrication of microelectrophoresis devices.

Micromachining was performed in polymethylmethacrylate (PMMA) using X-ray lithography for the fabrication of miniaturized devices (microchips) for potential applications in chemical and genetic analyses. The devices were fabricated using two different techniques: transfer mask technology and a Kapton mask. For both processes, the channel topography was transferred (1:1) to the appropriate substrate via the use of an optical mask. In the case of the transfer mask technique, the PMMA substrate was coated with a positive photoresist and a thin Au/Cr plating base. Following UV exposure, the resist was developed and a thick overlayer (approximately 3 microns) of Au electroplated onto the PMMA substrate only where the resist was removed, which acted as an absorber of the X-rays. In the other technique, a Kapton film was used as the X-ray mask. In this case, the Kapton film was UV exposed using the optical mask to define the channel topography and following development of the resist, a thick Au overlayer (8 microns) was electrodeposited onto the Kapton sheet. The PMMA wafer during X-ray exposure was situated directly underneath the Kapton mask. In both cases, the PMMA wafer was exposed to soft X-rays and developed to remove the exposed PMMA. The resulting channels were found to be 20 microns in width (determined by optical mask) with channel depths of approximately 50 microns (determined by x-ray exposure time). In order to demonstrate the utility of this micromachining process, several components were fabricated in PMMA including capillary/chip connectors, injectors for fixed-volume sample introduction, separation channels for electrophoresis and integrated fiber optic fluorescence detectors. These components could be integrated into a single device to assemble a system appropriate for the rapid analysis of various targets.

Sanger DNA-sequencing reactions performed in a solid-phase nanoreactor directly coupled to capillary gel electrophoresis.

A miniaturized, solid-phase nanoreactor was developed to prepare Sanger DNA-sequencing ladders which was directly interfaced to a capillary gel electrophoresis system. A biotinylated fragment of the rat brain actin gene (1 kbp) was amplified by PCR and attached to the interior wall of an (aminoalkyl)silane-derivatized fused-silica capillary tube via a biotin/streptavidin/biotin linkage. Coverage of the capillary wall with the biotinylated DNA averaged 77 +/- 10%. Stability of the anchored template under pressure (33 nL/s) and electroosmotic flows (11.3 nL/s) were favorable, requiring rinsing for > 150 h to reduce the surface coverage by only 50%. In addition, the immobilized template was stable toward temperatures required for preparing sequencing ladders, even under cycling conditions. Standard Sanger dideoxynucleotide termination performed in a large-volume (approximately 8 microL) solid-phase reactor using the thermally stable polymerase enzymes Taq and Vent and the polymerases T7 and Bst with off-line slab gel electrophoresis and autoradiographic detection indicated that acceptable fragment generation was achieved only in the case of the thermally stable polymerases. Banding was not apparent for T7 and Bst since all reagents were inserted into the column in a single plug at the beginning of the reaction. A small volume reactor (volume approximately 62 nL) was then used to perform DNA polymerase reactions and was coupled directly to a capillary gel column for separation. The capillary reactor was placed inside a thermocycler to control the temperature during chain extension and was directly connected to the gel column via zero dead volume fused-silica connectors. The complementary DNA fragments generated (C-track only) in the reactor were denatured using heat and directly injected onto the gel-filled capillary for size separation with detection accomplished using near-IR laser-induced fluorescence. Extension and single-base separation resolution of the C-track, which was directly injected onto the gel column, was estimated to be > 450 bases from the primer annealing site with plate numbers ranging from 1 x 10(6) to 2 x 10(6)/m.

Is there a role for physician assistants in community mental health?

The authors briefly describe the history and development of the medical discipline of physician assistants (PAs). A careful review of the literature reveals the limited use of PAs in psychiatry, usually only for primary health care needs. A model for using PAs as psychiatric assistants is presented, including the training required and a description of the clinical and administrative functions. The advantages of such a model are multiple. These include: 1) more effective and efficient use of the psychiatrist; 2) reduced costs of service; 3) increased primary medical screening capability in the CMHC; and 4) increased presence of ethnic minorities on the professional staff of the CMHC. Disadvantages of the model relate to training and "turf" issues. In view of the shortage and dissatisfaction of psychiatrists in CMHC settings, and other challenges to the provision of quality mental health care in the community, this model should be considered as a logical and positive response to that challenge. If the model is valid, then training facilities must make a systematic effort to recruit, train, and place psychiatric physician assistants in community agencies.

Quality, cost-effective psychiatric treatment: A CNS--MD collaborative practice model.

Health care reform presents an opportunity to design alternative health care delivery models. Psychiatric clinical nurse specialists and psychiatrists are particularly well positioned to work together as full and equal partners, to complement each other's practice and to provide cost-effective care with improved patient outcomes. In this case study, we show that, with the addition of psychotherapy provided by a CNS, the cost of care for the patient decreased from over $40,000 (average hospital cost only) to less than $4,000 per year. In addition, the patient attained competent self-care and an enhanced quality of life. Characteristics of effective collaboration are described. Replication of this design by psychiatric clinical nurse specialists is recommended.

Emergency department patterns in psychiatric visits during the holiday season.

STUDY OBJECTIVE: To determine the prevalence of psychopathology during the holiday season and which subpopulations are at greatest risk for holiday decompensation. DESIGN: A retrospective analysis of emergency department records. SETTING: ED of a university-affiliated hospital located in a mixed urban-agricultural catchment area in North Carolina. PARTICIPANTS: Eight thousand seven hundred fifty-six patient visits to the ED, with subsequent triage for psychiatric evaluation, for a 6-year period (1987 to 1993), were analyzed. RESULTS: We observed seasonal patterns in visits, with a general decrease in visits preceding holidays followed by an increase afterward. Substance abusers, men, and black patients were more likely to visit the ED than expected, particularly during the weeks surrounding Christmas. CONCLUSION: These results support the existence of a "Christmas effect" on ED visitations by patients with psychiatric symptoms. Understanding of these patterns may help emergency physicians predict the seasonal variation of such patient visits and apply preventive measures accordingly.

Transepithelial phosphate transport in rabbit proximal tubular cells adapted to phosphate deprivation.

Both renal and nonrenal cells in culture adapt to deprivation of Pi by increasing Na-dependent Pi uptake. We studied whether this change in uptake is reflected in an increased renal transepithelial Pi transport. We grew primary cultures of rabbit renal cortical cells in plastic flasks and subcultured them onto Millicell-HA filters. This produced cell monolayers, which structurally and functionally resembled proximal tubule. These cells performed Na-dependent net transepithelial transport of 32Pi in the apical-to-basolateral direction that was inhibited by phosphonoformic acid in the apical fluid or by ouabain in the basolateral fluid or by preincubation with parathyroid hormone. Overnight incubation at low Pi concentrations led to a progressive increase in 5-min Na-dependent Pi uptake into cell monolayers. Na-dependent Pi uptake was threefold higher following overnight incubation at 25 microM Pi, compared with 3 mM Pi, and the increase was one-half maximal with incubation at an extracellular Pi concentration ([Pi]) of 300 microM. This was associated with a decrease in Na-dependent transepithelial Pi flux to the basolateral fluid by the same cells, which fell dramatically following incubation at < or = 300 microM Pi. There was no change in Na-dependent uptake or transepithelial transport of L-glutamine. This adaptation to Pi deprivation in vitro appears to serve to restore depleted cell stores of Pi rather than to regulate transepithelial Pi transport.

Religious practices and alcoholism in a southern adult population.

OBJECTIVE: The study examined associations between religious variables and alcohol abuse and dependence among 2,969 North Carolina residents aged 18 to 97 who participated in the 1983-1984 National Institute of Mental Health Epidemiologic Catchment Area survey at its Piedmont location. METHODS: Six-month and lifetime prevalence of alcohol disorders were compared among participants reporting varying levels of religious activity. Data were collected on frequency of Bible reading, prayer, and church attendance; time spent watching or listening to religious programming on television or radio; importance of religion; religious denomination; and identification as "born-again" Christians. RESULTS: Recent and lifetime alcohol disorders were less common among weekly churchgoers and those who considered themselves born again. Recent, but not lifetime, alcohol disorders were also less common among respondents who frequently read the Bible or prayed privately. Alcohol disorders were more common among those who frequently watched or listened to religious television and radio. Lifetime, but not recent, alcohol disorders were more prevalent among members of Pentecostal denominations. CONCLUSIONS: Longitudinal study is necessary to further clarify and explain these relationships between religious practices and alcohol disorders.

Treatment of social phobia with clonazepam and placebo.

Clonazepam and placebo were administered in a double-blind pilot study to 75 outpatients with social phobia. The mean maximum dose of clonazepam was 2.4 mg/day at endpoint (range, 0.5 to 3 mg). Treatment was continued for up to 10 weeks. The results of an intent-to-treat analysis indicated superior effects of clonazepam on most measures. Response rates for clonazepam and placebo were 78.3 and 20.0%. Drug effects were apparent on performance and generalized social anxiety, on fear and phobic avoidance, on interpersonal sensitivity, on fears of negative evaluation, and on disability measures. Significant differences were evident by week 1, 2, or 6, depending upon the rating scale used. Clonazepam was well tolerated in general, although unsteadiness and dizziness were more severe and persistent than was the case for placebo subjects.

Magnetic resonance spectroscopy in social phobia: preliminary findings.

Proton localized magnetic resonance spectroscopy was studied in 20 social phobics and 20 age- and sex-matched controls. Stimulated Echo Acquisition Mode volume element localization was used with chemical shift imaging. Choline and creatine signal-to-noise ratios (SNRs) were significantly lower in social phobia than in controls in subcortical, thalamic, and caudate areas. In the social phobic group, N-acetylaspartate (NAA) SNR was significantly lower in cortical and subcortical regions, and ratios of NAA to other metabolites were lower in social phobia. Choline, creatine, and NAA SNRs were inversely correlated to total social phobia and fear symptoms, as measured by the Brief Social Phobia Scale, in the thalamic and noncortical gray areas. In a small number of patients who received clonazepam, posttreatment SNRs generally increased relative to baseline. Our results suggest a promising place for magnetic resonance spectroscopy in social phobia and also indicate potential pharmacodynamic uses of this technique.

Should physicians screen for depression in elderly medical inpatients?: Results of a decision analysis.

OBJECTIVE: We wish to determine whether or not elderly medical inpatients should be screened for depressive disorder using either 1) a self-rated depression scale (Geriatric Depression Scale), 2) "usual clinical assessment," or 3) neither, assuming that treatment with tricyclic antidepressants (TCAs) is the primary mode of intervention. METHOD: Based on recent data from epidemiological studies on the prevalence and course of depression, the test characteristics of available screening tests, and the efficacy and side-effects of traditional antidepressants, decision analysis is used to help decide whether or not clinicians should screen for depression in this setting. RESULTS: These calculations indicate that if screening is done solely to identify depressed patients for treatment with TCAs, then the highest utility lies in not screening; however, the difference in utilities between that decision and the decisions to either screen with GDS or screen by usual clinical assessment was only .04 units on a 0 to 100 scale, making the decision virtually a toss-up. Furthermore, even a small variation in one of several clinical factors or test characteristics could give screening a higher utility. In particular, if psychotherapy is considered as the primary intervention, then the utility of screening exceeds that of not screening. CONCLUSION: Characteristics of the screening test, clinical setting, types and safety of available treatments, each impact on the usefulness of screening and must be kept in mind when diagnosing and treating depressed medically ill elders hospitalized in acute care settings.

Systematics and body size: implications for feeding adaptations in New World monkeys.

The relationship between body size and feeding ecology is well established for primates. It is argued that the evolutionary history of modern New World monkeys and, in particular, the path to attainment of current body size is significant in understanding the similarities and differences between dietary strategies and other ecological parameters of similar-sized monkeys. Current interpretations of New World monkey evolutionary relationships are reviewed. Based on a synthesis of available body weights and the assumption that the earliest New World monkeys weighed close to 1 kg, similar to modern Aotus and Callicebus, predicted patterns of body size change in each lineage are given. Restrictions on directions of body size change in primates are discussed, and it is shown that "Stanley's Rule" offers a good explanation for differing body size ranges in New and Old World anthropoids. Predicted ecological correlates to body size drawn from the mammalian literature are offered and tested using data on New World monkeys, which show some concurrence and several interesting departures from predicted patterns. Sexual dimorphism in body weight of New World monkey species is reviewed, based on the new summary of body weight data given.