Detection of HBsAg in newborns

Cord blood samples collected from 150 newborns were tested for HBsAg using micro ELISA technique. Only 8 (5.3 per cent) out of 150 samples were found to be positive for HBsAg in variable titres. It is important to identify these HBsAg positive newborns so that appropriate measures could be adopted at the earliest to prevent the complications of HBsAg carriage.     

The study of fecal-Escherichia coli peritonitis-induced septic shock in a neonatal pig model

Peritonitis-induced septic shock in the neonate is associated with a high mortality. Because there exists no clinically relevant model to study resuscitation of these patients, a model using the neonatal pig was developed. After arterial and central venous cannulation, and placement of a left pulmonary-artery thermodilution catheter, 12 anesthetized neonatal pigs were "resuscitated" with fluids (5% albumin in lactated Ringer's solution at 15 ml/kg/hr), antibiotics, and correction of acidemia. The pigs were divided into two groups: a control group (n = 5), which was not subjected to peritonitis and which was killed after 6 hours of monitoring, and a septic group (n = 7), which was inoculated with an intraperitoneal injection of sterile pig feces and Escherichia coli and was monitored until death (mean survival time (S.D.) 546(159) minutes). Serial measurements of hemodynamic and laboratory data were obtained. While pigs in the control group showed no significant changes in these data as measured against time, the pigs in the experimental group showed an early transient rise in cardiac index which was significant (p less than .05) and which was followed by a steady decline in cardiac index until death. These changes in cardiac index were accompanied by a continuous decline in mean arterial pressure, central venous pressure, pulmonary artery pressure, and systemic vascular resistance index, while pulmonary vascular resistance index showed a gradual continuous rise. The observed changes in hemodynamic and laboratory data mimic those anticipated in the human neonate with peritonitis-induced septic shock. This model proves reliable and reproducible, and shows promise as a tool to study the resuscitation of neonates with septic shock.     

Atrial fibrillation: epidemiology, mechanisms and management

The incidence of AF, the most common sustained arrhythmia in clinical practice, increases with age and coronary artery disease, hypertension and valvular heart disease are common underlying substrates; however, occasionally, AF may occur without any underlying heart disease. The most widely accepted theory of its mechanism is Moe's multiple wavelet hypothesis, although recent studies are helping to shed light on other mechanisms, including the focal origin of AF in some patients. Most patients experience palpitations, but fatigue, dyspnoea, and dizziness may also occur. Therapy includes prevention of thromboembolism, control of rate, and restoration and maintenance of sinus rhythm. The risks and benefits of each treatment modality need to be assessed according to each patient's circumstances. Unlike other arrhythmias, there is still no highly successful therapy for treating AF. However, significant advances are being made using non-pharmacological approaches to either prevent or cure this troublesome arrhythmia.     

Timing of dental extractions in patients undergoing radiotherapy and the incidence of osteoradionecrosis: a systematic review and meta-analysis

This systematic review aimed to examine whether the incidence of osteonecrosis differed between patients who have dental extractions before or after radiotherapy (RT). The reported incidence of osteoradionecrosis (ORN) of the jaws following RT to the head and neck varies widely in the literature. Currently, for patients with head and neck cancer there are no universally accepted guidelines on the optimal timing of dental surgery relative to RT to minimise incident ORN. A literature review was conducted using the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) criteria. A search of PubMed, EMBASE, Evidence-Based Medicine, and Web of Science databases targeted literature published up to and including 10 April 2020. Two independent reviewers assessed studies for eligibility against inclusion criteria. An assessment of bias was conducted for each of the included studies and relevant data extracted. A meta-analysis was undertaken using the statistical methods described. Twenty-four of 708 studies were included. They were heterogeneous and included a wide variation of RT methods, head and neck malignancies, and comorbidities. While some concluded that the incidence of ORN was dependent on the timing of dental extractions in relation to RT, with regard to the risk of its development, others reported additional factors such as age, comorbidities, extent of surgical resection, and dose and field of radiation, as more important predictors than timing. In many there was consistent lack of detail around the timing of dental procedures in relation to the delivery of RT. From 21 studies including 36,294 patients, of whom 14,389 had extractions before RT, the pooled incidence of ORN was 5.5% (95% CI: 2.1% to 10.1%). Significant heterogeneity was found in Cochran’s Q-test (p < 0.001) and Higgins I² = 98.0%. From 21 studies including 37,805 patients, of whom 6030 had extractions after RT, the pooled incidence of ORN was 5.3% (95% CI: 2.9% to 8.2%). Significant heterogeneity was found in Cochran’s Q-test (p < 0.001) and Higgins I² = 80.0%. There was no statistically significant difference between these two groups (random-effects model Q=0.12, p=0.73). Large, longitudinal studies with a priori-specified methods are needed to identify, recruit, and prospectively follow patients with head and neck cancer for the onset of ORN after dental surgery. This will allow clinical guidelines to be established to assist clinicians to plan treatment when extractions are indicated in patients undergoing RT to the head and neck.