High-throughput organ-on-chip platform with integrated programmable fluid flow and real-time sensing for complex tissue models in drug development workflows.

Drug development suffers from a lack of predictive and human-relevant in vitro models. Organ-on-chip (OOC) technology provides advanced culture capabilities to generate physiologically appropriate, human-based tissue in vitro, therefore providing a route to a predictive in vitro model. However, OOC technologies are often created at the expense of throughput, industry-standard form factors, and compatibility with state-of-the-art data collection tools. Here we present an OOC platform with advanced culture capabilities supporting a variety of human tissue models including liver, vascular, gastrointestinal, and kidney. The platform has 96 devices per industry standard plate and compatibility with contemporary high-throughput data collection tools. Specifically, we demonstrate programmable flow control over two physiologically relevant flow regimes: perfusion flow that enhances hepatic tissue function and high-shear stress flow that aligns endothelial monolayers. In addition, we integrate electrical sensors, demonstrating quantification of barrier function of primary gut colon tissue in real-time. We utilize optical access to the tissues to directly quantify renal active transport and oxygen consumption via integrated oxygen sensors. Finally, we leverage the compatibility and throughput of the platform to screen all 96 devices using high content screening (HCS) and evaluate gene expression using RNA sequencing (RNA-seq). By combining these capabilities in one platform, physiologically-relevant tissues can be generated and measured, accelerating optimization of an in vitro model, and ultimately increasing predictive accuracy of in vitro drug screening.

Cystamine/cysteamine rescues the dopaminergic system and shows neurorestorative properties in an animal model of Parkinson's disease.

The neuroprotective properties of cystamine identified in pre-clinical studies have fast-tracked this compound to clinical trials in Huntington's disease, showing tolerability and benefits on motor symptoms. We tested whether cystamine could have such properties in a Parkinson's disease murine model and now provide evidence that it can not only prevent the neurodegenerative process but also can reverse motor impairments created by a 6-hydroxydopamine lesion 3 weeks post-surgery. Importantly, we report that cystamine has neurorestorative properties 5 weeks post-lesion as seen on the number of nigral dopaminergic neurons which is comparable with treatments of cysteamine, the reduced form of cystamine used in the clinic, as well as rasagiline, increasingly prescribed in early parkinsonism. All three compounds induced neurite arborization of the remaining dopaminergic cells which was further confirmed in ex vivo dopaminergic explants derived from Pitx3-GFP mice. The disease-modifying effects displayed by cystamine/cysteamine would encourage clinical testing.

Spatial Distribution of Venturia inaequalis Airborne Ascospores in Orchards.

ABSTRACT Apple scab (Venturia inaequalis) causes important economic losses in many apple production areas of the world. The disease is controlled by numerous fungicide applications regardless of the presence of ascospores in the orchard. Airborne ascospore concentration (AAC) can be measured in real time to time fungicide applications. However, the level of heterogeneity of the AAC in commercial orchards was unknown. Consequently, the spatial distribution of V. inaequalis ascospores was studied in a commercial apple orchard of 0.43 ha. The potential ascospore dose (PAD) and AAC were measured in 40 quadrats each of 108 m(2). In each quadrat, the AAC was monitored during the major rain events in spring 1999 and 2000 using spore samplers. The variance-to-mean ratio for the PAD and for most of the AAC sampling dates was >1, indicating an aggregated pattern of distribution. None of the frequency distributions of the most important ascospore ejection events followed the Poisson probability distribution, indicating that the pattern of distribution was not random. For all events, AAC had an aggregated pattern of distribution as suggested by the negative binomial distribution. The PAD followed neither the Poisson nor the negative binomial distribution. Geostatistical analyses confirmed the aggregated pattern of distribution. The cultivars had an effect on the PAD and AAC distribution pattern, but both PAD and AAC were not uniformly distributed within a block of the same cultivar. Therefore, the number, location, and height of samplers required to estimate AAC in orchards need to be investigated before using information on AAC for decision making.

Management of an infant with diffuse bullous pulmonary lesions using high-frequency oscillatory ventilation.

PURPOSE: To describe the anesthetic and ventilatory management of an infant with diffuse pulmonary bullous lesions. CLINICAL FEATURES: Four successive operations were scheduled for an infant with diffuse pulmonary bullous lesions. At the age of seven weeks, conventional positive pressure ventilation during laparotomy for intestinal occlusion led to arterial desaturation. This was corrected by returning to spontaneous respiration and deep inhalation anesthesia with halothane. Based on our ICU experience and due to a potential impaired oxygenation during conventional ventilation, we chose high-frequency oscillatory ventilation (HFOV) for bilateral sequential thoracotomies for bullectomies at the age of five months. We elected the same ventilatory mode for laparotomy for intestinal obstruction secondary to a polyp at the age of six months. This ventilatory mode was combined with total intravenous anesthesia and epidural analgesia and provided optimal oxygenation and ventilation as well as vital signs stability. CONCLUSION: High frequency oscillatory ventilation is a safe technique that may be used in the operating room in cases where conventional ventilation failed to provide satisfactory gas exchange.

Epidural anaesthesia for elective caesarean section does not influence fetal umbilical artery blood flow indices.

This prospective study was completed to determine the influence of epidural anaesthesia on the fetoplacental circulation of normal subjects. Thirty-seven normal pregnant patients at term, undergoing elective Caesarean section, had Doppler measurements of the fetal umbilical artery blood flow velocity before and after epidural anaesthesia using lidocaine 2% without epinephrine. There were no differences in systolic/diastolic, resistance or pulsality indices following epidural anaesthesia. These results suggest that this technique has no adverse effect on fetoplacental circulation in normal non-labouring subjects.

Propofol for pulsed dye laser treatments in paediatric outpatients.

Pulsed dye laser is a new treatment for port-wine stains, congenital lesions in the cutaneous vascular plexus. We report our anesthetic experience with paediatric outpatients treated in the dermatology clinic. From April to November 1993, 48 ASA 1 children were anaesthetised for a total of 105 consecutive laser treatments. The youngest was eight months old, the oldest was 12 yrs old and most of the sessions (43%) were done for children aged from two to four years. Each received acetaminophen (10 mg.kg-1 p.o.) before treatment. A propofol infusion was chosen for anaesthesia to achieve early discharge and to reduce the incidence of postoperative emesis. The infusion was adjusted to maintain blood pressure within 20% of baseline and to keep the child immobile. The dose was progressively reduced during the procedure from 400 micrograms.kg-1.min-1 to 100 micrograms.kg-1.min-1. Fentanyl (2 micrograms.kg-1 i.v.) was added for analgesia. Respiration was spontaneous through a nasopharyngeal airway (air in oxygen 40%). Anaesthesia proceeded uneventfully in all cases and lasted for 15-30 min (63% of treatments), 30-45 min (28%) or 45-60 min (9%) according to the size of the lesion. The mean stay in the recovery room was 25.1 min and none of the patients experienced emesis. Our experience shows that general anaesthesia with propofol supplemented with fentanyl offers a rapid onset and awakening, a painless treatment and an immobile child. It is a safe solution to alleviate pain from repeated painful procedures even in small children under two years of age.

Diagnosis of vertical HIV-1 transmission using the polymerase chain reaction and dried blood spot specimens.

We have used the polymerase chain reaction (PCR) to detect HIV proviral sequences in minute amounts of peripheral blood collected onto newborn screening blotters. Forty-three newborns, infants, and children of HIV-infected mothers were serially studied: dried blood spot (DBS) specimens were processed for PCR; serum was assayed for HIV antibodies, p24 antigen, and immunoglobulins; mononuclear cells were cultured and CD4 cells were quantitated by immunofluorescence. There was excellent agreement between the results of blood spot PCR, viral culture, and clinical and immunological indicators of HIV infection. Eighteen of 19 infected children tested positive by both PCR and culture, including six asymptomatic infants who were less than 10 weeks of age. As expected, p24 antigen capture assays were insensitive, detecting only 13 of the 19 infected children. One infected infant tested positive by PCR, but negative by culture and antigen. This infant was seropositive at 27 months and had pronounced hypergammaglobulinemia in association with non-specific symptoms. Twenty-four of the 43 infants were asymptomatic with normal immune profiles, declining antibody levels and no evidence of infection. These children tested repeatedly negative by PCR, culture, and p24 antigen assays. Our results indicate that DBS PCR is a sensitive, specific, and cost-effective alternative to viral culture for the early diagnosis (or exclusion) of perinatal HIV infection. DBS sampling opens the way for large-scale prospective studies to determine the exact rates of vertical HIV transmission in industrialized, as well as, nonindustrialized countries.

Pediatric liver transplantation: the Montreal experience.

The introduction of cyclosporine A in 1980 greatly improved the survival of children with end-stage liver disease undergoing orthotopic liver transplantation. The average 1-year survival rate following hepatic transplantation increased from 30% in 1963 to 70% in 1980. This report summarizes the initial experience of two pediatric hospitals in Montreal--Hôpital Ste-Justine and Montreal Children's Hospital. Since December 1985, 13 orthotopic liver transplantations have been performed in 11 patients: six females and five males. The median age was 18 months (range, 13 months to 17 years) and the median weight was 10 kg (range, 8.5 to 38 kg). The indications for transplantation were biliary atresia (5 patients), tyrosinemia (2 patients), biliary hypoplasia (1 patient), Amerindian cirrhosis (1 patient), Crigler-Najjar syndrome, type I (1 patient), and fulminant non-A, non-B hepatitis with grade IV encephalopathy (1 patient). Immunosuppression was ensured by cyclosporine A, azathioprine, and steroids. The function of 11 grafts was immediate following revascularization of the grafts. One graft had delayed function due to preservation injury, and one had primary nonfunction. Surgical complications included bile peritonitis (1), ruptured aneurysm of an aortic conduit (1), and thrombosis of the hepatic artery necessitating retransplantation (2). Three of our patients died, one from postoperative cerebral edema, one of primary nonfunction of the graft, and one of ruptured aneurysm of an aortic conduit. Our overall survival rate was 72% with a follow-up of 3 to 32 months. Pediatric liver transplantation can now provide successful treatment and cure of liver diseases considered, until recently, dismal and hopeless.

Acute epiglottitis: an overview.

The authors make use of their experience in the epidemiology, diagnosis, treatment and complications of acute epiglottitis. This study is based on the examination of 212 consecutive cases of infants hospitalized at the "Hôpital Sainte-Justine pour les enfants" (Montreal, Quebec, Canada). These patients were treated following the protocol of a multidisciplinary study that began on January 1, 1974, and continues at the present time. The authors conclude the following: Acute epiglottitis still contributes to sudden death in infants; The overall care of the patient requires a medical transfer with the possibility of an emergency ventilation and intubation; The early diagnosis and treatment are directed by the same protocol that is established by the multidisciplinary work of the anesthesiological, pediatrician, radiologist and ENT specialists.

Nausea and vomiting after strabismus surgery in preschool children.

The incidence of nausea and vomiting after strabismus surgery was studied in 64 children aged one to six years. Incidence was determined in the post-anaesthesia recovery room (PARR), in the same day surgery (SDS) unit, and at home on days one and two after the operation. After induction of anaesthesia, the children received an intravenous injection of droperidol (50 micrograms . kg-1) or saline in a double-blind randomized fashion, and an intravenous injection of glycopyrrolate (7.5 micrograms . kg-1) or atropine (10 micrograms . kg-1) in an open randomized fashion. The incidence of emetic symptoms was highest in the SDS unit and at home on day one. Droperidol slightly but significantly delayed awakening and was not, at least in this particular age group, associated with any difference in postoperative sickness. Despite theoretical advantages, glycopyrrolate offered no significant benefit over atropine as far as postoperative emesis was concerned.

Palliative surgery in tetralogy of Fallot.

Because much controversy surrounds the palliative surgical treatment of young children with tetralogy of Fallot the authors review their experience over 13 years with two procedures--the Blalock-Taussig operation and the Waterston shunt. Blalock shunts were performed 195 times in 172 patients; 147 had a single Blalock anastomosis which carried them through the critical period and allowed for later correction of the tetralogy. Thrombosis of the Blalock anastomosis occurred in two patients in the early postoperative period. In 23 patients a second shunt was necessary after the first Blalock shunt became inadequate in spite of being patent. The age of the children ranged from 2 weeks to 9 years, 74% being operated upon under the age of 2 years. There were four early deaths (2%) and five late deaths (2.5%) in this group. Of the last 91 consecutive patients operated upon between Sept. 1, 1972 and June 30, 1980 none have died. Between September 1968 and June 1980, 14 patients with tetralogy of Fallot underwent a Waterston shunt. Their ages ranged from 2 days to 4 years. Six patients were younger than 35 days at the time of operation. There were two operative deaths in this group. The Waterston shunt carries a high risk and is reserved for the occasional patient who needs palliation during the first weeks of life and in whom the anatomy of the subclavian artery does not favour a good Blalock-Taussig shunt. The Blalock-Taussig operation is preferred because it is safe and gives good sustained clinical results. The mortality was much lower than previously reported. The growth of the pulmonary arteries was good in most patients. The Blalock shunt did not increase the pulmonary resistance and it did not influence the operative mortality.

Pre-anaesthetic medication in paediatric day-care surgery.

Pre-anaesthetic medication has the primary aim of making the whole process of anaesthesia smooth and agreeable. This prospective blind study was planned to compare the efficacy of three active drugs and a placebo as premedication in a paediatric population undergoing operation on a day care basis. One hundred and fifty-nine patients between one and 12 years of age were assigned randomly to one of four groups who received either hydroxyzine 0.5 mg . kg-1 (n - 43) promethazine 0.5 mg . kg-1 (n 40) diazepam 0.1 mg . kg (n - 378) or placebo (n - 36) by mouth, 60 minutes before operation. Observations in the operating room included the emotional state of the patient on arrival, quality of induction and complications. In the recovery room time for emergence from anaesthesia, complications and requirements for analgesia were recorded. The parents were asked for return a questionnaire detailing psychological and physical complications during three postoperative days. There was no difference between the groups in any of the factors examined. From this study we conclude that children undergoing surgical operations and anaesthesia on a day care basis should not receive pharmacological premedication, not because of overwhelming risk from its use, but because of the absence of any benefit.