Optogenetic activation of melanin-concentrating hormone neurons increases non-rapid eye movement and rapid eye movement sleep during the night in rats.

Neurons containing melanin-concentrating hormone (MCH) are located in the hypothalamus. In mice, optogenetic activation of the MCH neurons induces both non-rapid eye movement (NREM) and rapid eye movement (REM) sleep at night, the normal wake-active period for nocturnal rodents [R. R. Konadhode et al. (2013) J. Neurosci., 33, 10257-10263]. Here we selectively activate these neurons in rats to test the validity of the sleep network hypothesis in another species. Channelrhodopsin-2 (ChR2) driven by the MCH promoter was selectively expressed by MCH neurons after injection of rAAV-MCHp-ChR2-EYFP into the hypothalamus of Long-Evans rats. An in vitro study confirmed that the optogenetic activation of MCH neurons faithfully triggered action potentials. In the second study, in Long-Evans rats, rAAV-MCH-ChR2, or the control vector, rAAV-MCH-EYFP, were delivered into the hypothalamus. Three weeks later, baseline sleep was recorded for 48 h without optogenetic stimulation (0 Hz). Subsequently, at the start of the lights-off cycle, the MCH neurons were stimulated at 5, 10, or 30 Hz (1 mW at tip; 1 min on - 4 min off) for 24 h. Sleep was recorded during the 24-h stimulation period. Optogenetic activation of MCH neurons increased both REM and NREM sleep at night, whereas during the day cycle, only REM sleep was increased. Delta power, an indicator of sleep intensity, was also increased. In control rats without ChR2, optogenetic stimulation did not increase sleep or delta power. These results lend further support to the view that sleep-active MCH neurons contribute to drive sleep in mammals.

Systems Genomics Identifies a Key Role for Hypocretin/Orexin Receptor-2 in Human Heart Failure.

BACKGROUND: The genetic determinants of heart failure (HF) and response to medical therapy remain unknown. We hypothesized that identifying genetic variants of HF that associate with response to medical therapy would elucidate the genetic basis of cardiac function. OBJECTIVES: This study sought to identify genetic variations associated with response to HF therapy. METHODS: This study compared extremes of response to medical therapy in 866 HF patients using a genome-wide approach that informed the systems-based design of a customized single nucleotide variant array. The effect of genotype on gene expression was measured using allele-specific luciferase reporter assays. Candidate gene transcription-deficient mice underwent echocardiography and treadmill exercise. The ability of the target gene agonist to rescue mice from chemically-induced HF was assessed with echocardiography. RESULTS: Of 866 HF patients, 136 had an ejection fraction improvement of 20% attributed to resynchronization (n = 83), revascularization (n = 7), tachycardia resolution (n = 2), alcohol cessation (n = 1), or medications (n = 43). Those with the minor allele for rs7767652, upstream of hypocretin (orexin) receptor-2 (HCRTR2), were less likely to have improved left ventricular function (odds ratio: 0.40 per minor allele; p = 3.29 × 10(-5)). In a replication cohort of 798 patients, those with a minor allele for rs7767652 had a lower prevalence of ejection fraction >35% (odds ratio: 0.769 per minor allele; p = 0.021). In an HF model, HCRTR2-deficient mice exhibited poorer cardiac function, worse treadmill exercise capacity, and greater myocardial scarring. Orexin, an HCRTR2 agonist, rescued function in this HF mouse model. CONCLUSIONS: A systems approach identified a novel genetic contribution to human HF and a promising therapeutic agent efficacious in an HF model.

Natural killer function in flow cytometry. I. Evaluation of NK lytic activity on K562 cell line.

Flow cytometry has been employed to establish an NK assay using the K562 target cell line. These cells show a perpendicular light scatter (PLS) characteristically different from lymphocytes. Other physical parameters, such as forward light scatter (FLS), do not discriminate between the two populations, since dead K562 cells display similar FLS characteristics as effector cells. Killed cells are stained with propidium iodide and followed by flow analysis. It was advisable to add the dye in the medium so that, as long as the target cells are killed they will also be stained. Moreover the flow cytometric and trypan blue evaluation of target cell death rate showed a stronger correlation than did either test with the conventional 51Cr release assay, the first two methods both being based on the same biological mechanism.

Clostridium difficile colitis induced by cytarabine.

Pseudomembranous enterocolitis (PMC) has become a widely recognized syndrome of nausea, abdominal distention, and severe (frequently bloody) diarrhea (1). While this syndrome was first associated with the administration of clindamycin, almost all antimicrobial drugs can serve as predisposing agents (2). We wish to report a patient with typical PMC induced by the administration of cytarabine.

Dibromodulcitol in the treatment of metastatic hemangiopericytoma.

Hemangiopericytoma is an uncommon sarcoma arising from the pericapillary cells. While the rarity of this lesion precludes randomized investigation, metastatic hemangiopericytoma has been noted to respond to a variety of agents, including vincristine, adriamycin, actinomycin, and high-dose methotrexate. We wish to report an unusual case of this disease which failed to respond to the above but then exhibited a marked response to dibromodulcitol. In light of the unusual nature of this response, we would like to suggest a controlled trial of the use of dibromodulcitol in patients with this rare tumor.

In vitro methods to evaluate metal-cell interactions.

The aim of this study was to test different metals, widely employed in constructing prosthetic devices, by in vitro methods. Biological effects of such materials were analyzed through four different assays on human lymphocytes and granulocytes. The lymphocyte proliferation assay gave quantitative results, while the viability test showed the morphological appearance of the cells correlated well with previous results. NK cytotoxicity and granulocyte chemokinesis tests provided interesting data on leucocyte performance when challenged with metals. Therefore the present study adds new basic information on cell behaviour when metal products are present in the body, e.g. around devices implanted in human tissues.

Ensuring competencies of multidisciplinary staff in patient-focused care.

Faced with rising health care costs and consumer demands, hospitals are finding creative ways to streamline the delivery of patient care. One such approach is patient-focused care (PFC), in which hospitals bring services to the patient's beside and cross-train staff. The success of PFC depends on training and measuring staff competence in the new skills. This article describes how to implement an educational plan based on competencies for a successful transition to PFC.

Heart-smart service.

Cardiology patients--direct and ED admits--go to Lancaster General Hospital's Cardiology Admissions Unit (CAU) to receive care until a bed is available in an inpatient unit. The CAU yields high patient volume, positive patient and staff feedback, decreased ED length of stay, prompt initiation of treatment protocols, and more effective discharge planning.

Updated and expanded study of polycythemia vera and other myeloproliferative neoplasms in the tri-county area.

INTRODUCTION: The results of a 2001-2005 polycythemia vera (PV) investigation in Eastern Pennsylvania revealed a disease cluster plus underreporting and false reporting to the Pennsylvania Cancer Registry (PCR). PURPOSE: The objectives of this study were 1) to assess PV reporting to the PCR in 2006-2009, 2) to determine whether a cancer cluster persisted, and 3) to determine whether other myeloproliferative neoplasms (MPNs), including essential thrombocytopenia (ET), were subject to similar reporting problems. METHODS: Cases were identified from: 1) PCR records from the Tri-County, 2) reviewing billing records at Tri-County hematologist/oncologist offices, and 3) self-identification. An expert panel of physicians reviewed medical records and determined "true," "false," or "indeterminate" cases reported to the PCR. The analyses were conducted to determine sensitivity and positive predictive value (PPV) of case reporting to the PCR, estimate cancer incidence rates, and evaluate the presence of cancer clusters. RESULTS: Of 290 cases identified, 90% were from the original PCR, 9% from billing records, and 1% from self-report. Fifty-five cases consented to participate, and medical records were obtained for 44. The expert panel determined that 45% were true cases, 32% were false cases, and 23% were indeterminate. PV had 100% (95% CI, 59-100) sensitivity, but only 47% PPV (95% CI, 20-70): ET had 78% (95% CI, 47-99) sensitivity and 100% PPV (95% CI, 59-100). Low participation and chart review rates led to rates with wide confidence intervals. We did not identify any PV cancer clusters, but we did identify a cluster of 9 ET cases in the Wilkes-Barre, Pennsylvania area. CONCLUSION: The current study was limited by the low response rate (22%) from MPN patients in the Tri-County area. This study identified 47% PPV for PV reporting and 100% PPV for ET.

Lymphocyte clones from old subjects: growing rate and functional activity.

Old subjects exhibit a decline in circulating T cells and an impaired proliferative response to mitogens, plus a relative increase in cells with NK phenotype not associated with a concomitant increase in their cytolitic activity.In the present study a limiting dilution assay was used to evaluate the phenotype, the functional activity and the proliferative capacity of clones obtained from peripheral blood lymphocytes of old and young subjects. CD5+ CD8+ clones from old people showed a significant impairment in their proliferative capacity and a decreased lytic activity against K562 and P815-IgG cell lines.

Cellular response and anti-HBs synthesis in vitro after vaccination with yeast-derived recombinant hepatitis vaccine.

Two groups of subjects receiving two different doses of yeast-derived recombinant hepatitis B surface antigen (rHBsAg) (10 micrograms Gen-HB-Vax, Merck Sharp and Dohme and 20 micrograms Engerix-B, Smith Kline and French) were investigated for in vitro specific humoral and cellular response to the native protein. In vitro proliferative response was dependent on the following critical variables: (1) antigen-specific precursor lymphocytes were present in the peripheral blood for a very short time; (2) the number of circulating specific precursors was dependent on the dose of HBsAg used for vaccination; (3) the presence of antigen-presenting cells was necessary to obtain a blastogenic response in vitro. In vitro proliferation was enhanced by the addition of recombinant interleukin 2 (rIL-2). Spontaneous and stimulated (anti-CD3, pokeweed mitogen) anti-HBs antibody production in vitro was obtained in only eight out of 20 subjects after the fourth boost. Although a different immunogenicity of the two vaccines cannot be excluded, these data strongly suggest that T and B cells responsive to HBsAg present different kinetics of recirculation in the peripheral blood, depending on the antigen dose used for immunization.

Age-associated changes in CD8+ and CD16+ cell reactivity: clonal analysis.

A cloning technique was used to estimate the frequency of proliferating T cell precursors, the growth capacity of clone-forming cells and the functional activity of clones established in vitro from peripheral blood lymphocytes of young and old people. The mean frequency of proliferating precursors was lower in the elderly as was the proliferative capacity of CD8+ clones. In contrast, CD4+ and CD16+ clones showed a proliferation similar to that obtained from young subjects. When the clones were examined for their functional activity, CD4+ clones from both groups failed to show any cytolytic activity, while CD8+ clones exerted cytolysis against K562 and in antibody-dependent cell-mediated cytotoxicity but this function was reduced in clones derived from old subjects. Similarly, CD16+ clones from the elderly showed a decreased activity at some effector-to-target cell ratios. We conclude that the impaired functional activity (T or NK-dependent) found in the peripheral blood of aged subjects persists after in vitro selection when these cells are analysed at clonal level.