Engineered Cas12i2 is a versatile high-efficiency platform for therapeutic genome editing.

The CRISPR-Cas type V-I is a family of Cas12i-containing programmable nuclease systems guided by a short crRNA without requirement for a tracrRNA. Here we present an engineered Type V-I CRISPR system (Cas12i), ABR-001, which utilizes a tracr-less guide RNA. The compact Cas12i effector is capable of self-processing pre-crRNA and cleaving dsDNA targets, which facilitates versatile delivery options and multiplexing, respectively.

Cell-free protein synthesis of CRISPR ribonucleoproteins (RNP).

Cell-free protein synthesis is a powerful tool to produce recombinant proteins, and as an open system, can often integrate all or part of downstream assays. Here we describe in vitro synthesis of the Streptococcus pyogenes type II-A CRISPR-Cas9 ribonucleoproteins (SpCas9 RNPs), consisting of the effector protein and the single guide RNAs (sgRNAs). In spite of its large molecular weight (160kDa), the SpCas9 effector is expressed relatively well from linear DNA templates under T7 promoter in commercial reconstituted cell-free protein synthesis systems.

Multiplex Single-Molecule Kinetics of Nanopore-Coupled Polymerases.

DNA polymerases have revolutionized the biotechnology field due to their ability to precisely replicate stored genetic information. Screening variants of these enzymes for specific properties gives the opportunity to identify polymerases with different features. We have previously developed a single-molecule DNA sequencing platform by coupling a DNA polymerase to an α-hemolysin pore on a nanopore array.

Protective Propensity of Race or Environmental Features in the Development of Barrett's Esophagus in African Americans - A Single Center Pilot Study.

Background And Study Aims: Barrett's Esophagus (BE) is a well-recognized pre-malignant condition. Previous data indicate histologically confirmed BE frequency varies by ethnicity in the United States. However, clinical factor assessment to explain this has only occurred in a veteran population to date.

Stent type used does not impact complication rate or placement time but can decrease treatment cost for benign and malignant esophageal lesions.

Aim: To evaluate if differences exist between self-expanding esophageal metal stents (SEMS) and self-expanding esophageal plastic stents (SEPS) when used for benign or malignant esophageal disorders with regard to safety, efficacy, clinical outcomes, placement ease and cost.

Methods: A retrospective analysis was performed to evaluate outcome in patients having SEPS/SEMS placed for malignant or benign esophageal conditions from January 2005 to April 2012. Inclusion criteria was completed SEMS/SEPS placement.

African American ethnicity is not associated with development of Barrett's oesophagus after erosive oesophagitis.

Background: Barrett's oesophagus is the primary risk factor for oesophageal adenocarcinoma; erosive oesophagitis is considered an intermediate step with Barrett's oesophagus development potential upon healing. Barrett's oesophagus occurs in 9-19% following erosive oesophagitis but minimal data exists in African Americans. The study aim was to determine if ethnicity is associated with Barrett's oesophagus formation following erosive oesophagitis.

Proton radiotherapy dose perturbations caused by esophageal stents of varying material composition are negligible in an experimental model.

Background: Self-expanding metal and plastic esophageal stents (SEMS and SEPS, respectively) are used in conjunction with chemoradiation for palliation of malignant dysphagia. To date, the dosimetric effects of stents undergoing proton radiotherapy are not known.

Study Aim: To investigate the proton radiotherapy dose perturbations caused by esophageal stents of varying designs and materials undergoing external beam treatment for esophageal cancer.

Leadership in surgery for public sector hospitals in Jamaica: strategies for the operating room.

The barriers to health care delivery in developing nations are many: underfunding, limited support services, scarce resources, suboptimal health care worker attitudes, and deficient health care policies are some of the challenges. The literature contains little information about health care leadership in developing nations. This discursive paper examines the impact of leadership on the delivery of operating room (OR) services in public sector hospitals in Jamaica.

Infection control practice in the operating room: staff adherence to existing policies in a developing country.

Context: Infection control interventions are important for containing surgery-related infections. For this reason, the modern operating room (OR) should have well-developed infection control policies. The efficacy of these policies depends on how well the OR staff adhere to them.

Propofol sedation in patients undergoing colonoscopy in Jamaica.

Background: Propofol sedation is increasingly used for colonoscopy and may be associated with increased satisfaction and efficiency in diagnostic and therapeutic endoscopy. However propofol has a relatively narrow therapeutic window as it frequently produces deep sedation, and can precipitate respiratory depression.

Aim: To determine the efficacy, safety and patient satisfaction with propofol sedation in patients undergoing colonoscopy at the University Hospital of the West Indies (UHWI).

Direct-acting antiviral therapy for hepatitis C: attitudes regarding future use.

Introduction: Response to current therapy of hepatitis C virus (HCV) is suboptimal. Direct-acting antiviral therapies (DAA) are expected to improve treatment outcomes. Additional treatments for HCV will invariably make therapeutic choices and patient management more complex.

Prevalence of needlestick injuries and other high risk exposures among healthcare workers in Jamaica.

Objective: To assess the prevalence of needlestick injuries (NSIs) and other high risk exposures among healthcare workers at two hospitals in Jamaica.

Methods: Employing a cross-sectional study design, medical personnel (physicians, nurses) at two hospitals in Jamaica, were studied, utilizing a structured questionnaire consisting of 14 items to collect data on needle stick injuries and other injuries.

Results: There were 67 needlestick injuries in 47 persons.

Knowledge and practice of occupational infection control among healthcare workers in Jamaica.

Objective: To assess the knowledge, compliance and practice among healthcare workers of occupational infection control at two hospitals in Jamaica.

Methods: Employing a cross-sectional study design, medical personnel (physicians and nurses) at two hospitals in Jamaica, were studied, utilizing a structured questionnaire consisting of 14 items to collect the data.

Results: Participants considered the following fluids, not blood stained, high risk for HIV transmission: breast milk (79%), saliva (14%), urine (27%), pleural fluid (53%), CSF (55%), synovial fluid (37%), faeces (27%), peritoneal fluid (53%) and vomitus (21%).

Pulmonary hypertension: a review of the aetiology, pathophysiology and management.

Pulmonary hypertension (PH) is defined as a systolic pulmonary artery pressure (PAP) above 30 mmHg and a mean PAP above 25 mmHg. Pulmonary hypertensive diseases (PHDs) encompass a myriad of conditions that cause pulmonary hypertension (PH), hence the Evian Classification was developed for the categorization of the various causes. Pulmonary hypertensive diseases are complex conditions that are difficult to treat and in the case of primary pulmonary hypertension, there is no known cure.

A national survey on preoperative fasting policies and practices in Jamaican hospitals.

Controversy has arisen regarding the length and nature of the preoperative fast that should be required of patients with normal gastric emptying time undergoing elective surgery. Various studies and editorials have indicated that the traditional preoperative fasting policy of "NPO after midnight" may be illogical as it makes no distinction between solid foods and clear fluids. Successive National Surveys conducted in the United States of America (USA) have shown an increasing number of Ambulatory Surgery Hospitals adopting more liberal preoperative fasting guidelines.

Thirty-five years of cardiac surgery in Jamaica.

A retrospective review of the files of all patients who underwent cardiac surgery at the University Hospital of the West Indies (UHWI) and the Bustamante Hospital for Children (BHC), during the period April 1968 to June 2003 was undertaken. Data collected included age, gender New York Heart Association risk score, type and date of cardiac surgery. The mortality rate of patients who underwent surgery during the period January 1994 to June 2003 was also analyzed A total of 2202 patients had undergone cardiac surgery (CS) in Jamaica during the study period of 35 years and two months.

Initial experience with beating-heart single valve replacement surgery at the University Hospital of the West Indies, Kingston, Jamaica.

The objective of this study was to examine the consequences of performing single cardiac valve replacement procedures utilizing a beating-heart technique on typical patients presenting to the cardiothoracic surgery service for aortic or mitral valve replacement. Beating heart aortic (4) or mitral valve (1) replacement was performed on patients from July 2000 to November 2002. A stratified sample of five patients who underwent standard arrested-heart single valve replacement procedures between April 1997 and November 2002 was selected for retrospective comparison with the beating-heart group.

Complex regional pain syndrome.

A previously well fifty-five year-old female household helper developed complex regional pain syndrome Type II (reflex sympathetic dystrophy) following a minor injury to her left hand. She had marked hyperaesthesia and allodynia and was unable to perform her household work and to participate in the required physiotherapy. Following a series of stellate ganglion block, neurostimulation as well as physical therapy, there was a dramatic improvement in her condition and she was able to return to normal function.

Thymic surgery in Jamaica 1992-2000.

The treatment for thymic tumours and/or myaesthenia gravis (MG) includes thymectomy. Controversy exists as to the optimal timing and operative approach to thymectomy. At the University Hospital of the West Indies, Kingston, Jamaica, the results of thymic surgery during the period 1992 to 2000 were studied retrospectively.

Knowledge and fears of anaesthesia and surgery. The Jamaican perspective.

This study was undertaken to assess patients' knowledge and perceptions, fears and concerns regarding perioperative management. 300 patients were interviewed consecutively and a questionnaire was completed for each patient. 25% admitted to having anxiety about their upcoming operation.

Analysis of human cytomegalovirus nucleoprotein complexes.

When chromatin was isolated from cells infected with human cytomegalovirus, the virus DNA remained with the chromatin fraction. If deproteinized virus DNA was added to either isolated nuclei or chromatin, the DNA was lost during the chromatin isolation. When isolated chromatin from cytomegalovirus-infected cells was banded in isopycnic metrizamide gradients, a single peak with a density of 1.