The role of glutathione in carboplatin ototoxicity in the chinchilla

The role of glutathione in carboplatin ototoxicity was investigated in the chinchilla. Chinchillas hearing was tested with both distortion product otoacoustic emissions (DPOAE) and evoked potentials recorded from a chronic electrode in the inferior colliculus (IC). All subjects had an osmotic pump fitted to their right ear and it received buthionine sulfoximine (BSO) at a dose of 15 mM delivered at 5 ml per hour for 14 days. A group (N=4) was given a double dose of carboplatin (25 mg/kg i.p. for 2 days). The pump was implanted three days before the carboplatin dose. The BSO treated ears showed a greater loss in both evoked potential and DPOAE measures, as well as substantially fewer missing hair cells. The results implicate reactive oxygen species (ROS) as a common factor in ototoxic reactions because suppression of glutathione antioxidant leads to greater ototoxic reactions.     

Induction for overseas qualified doctors

This study describes a strategy for the integration of overseas doctors with different professional and cultural backgrounds. A central induction course, complementing local trust-based induction programmes, was developed and evaluated by the London Deanery. Most participants found the course helpful, and their comments were used to further improve it.     

Clostridium perfringens pleuropulmonary infection and septic shock: case report and population-based laboratory surveillance study

We report a rare case of necrotizing pneumonia, empyema, and septic shock caused by Clostridium perfringens. Population-based laboratory surveillance was subsequently conducted that identified an annual incidence of invasive C. perfringens disease of 0.83 per 100,000 population with a striking age-related increased risk for acquisition.     

Revascularization in severe ventricular dysfunction (15% ≤ LVEF ≤ 30%): a comparison of bypass grafting and percutaneous intervention

Background

We sought to determine the optimal approach to revascularization of patients with severe left ventricular (LV) dysfunction.

Methods

We conducted a single-center observational study of 117 consecutive patients who had severe LV dysfunction (15% ≤ LV ejection fraction ≤ 30%) and underwent either coronary artery bypass grafting (CABG, n = 69) or percutaneous revascularization (n = 48) between 1992 and 1997.

Results

The CABG group was younger (62 versus 67 years, p = 0.026), and fewer previous bypasses (7% versus 40%, p < 0.0001) and fewer prior percutaneous revascularizations (16% versus 42%, p = 0.0019) were noted. More vessels were revascularized (3 ± 0.8 versus 1.5 ± 0.7, p < 0.0001), and revascularization was more complete by CABG (84% versus 48%, p < 0.0001). Morbidity and mortality at 30 days were similar, and there was no significant difference in 3-year survival (73% versus 67%), although 3-year cardiac event-free survival (52% versus 25%, p = 0.0011) and 3-year target vessel revascularization-free survival (71% versus 41%, p < 0.0001) were significantly better in the CABG group, and LV ejection fraction was significantly improved after CABG. In the subgroup of patients 65 years of age or older and those without proximal left anterior descending coronary artery lesions, significant benefit of CABG in cardiac event-free and target vessel revascularization-free survival disappeared.

Conclusions

We found that in clinically selected patients with severe ventricular dysfunction, CABG compared with percutaneous revascularization achieves more complete revascularization, improved LV function, fewer cardiac events, and fewer target vessel revascularizations, but does not affect mid-term survival. A prospective controlled trial with defined criteria for treatment assignment is warranted to confirm our results regarding the two revascularization strategies in patients with severe LV dysfunction.     

Gamma-aminobutyric acid circuits shape response properties of auditory cortex neurons

Neurons containing gamma aminobutyric acid (GABA) are widely distributed throughout the primary auditory cortex (AI). We investigated the effects of endogenous GABA by comparing response properties of 110 neurons in chinchilla AI before and after iontophoresis of bicuculline, a GABA(A) receptor antagonist, and/or CGP35348, a GABA(B) receptor antagonist. GABA(A) receptor blockade significantly increased spontaneous and driven discharge rates, dramatically decreased the thresholds of many neurons, and constricted the range of thresholds across the neural population. Some neurons with 'non-onset' temporal discharge patterns developed an onset pattern that was followed by a long pause. Interestingly, the excitatory response area typically expanded on both sides of the characteristic frequency; this expansion exceeded one octave in a third of the sample. Although GABA(B) receptor blockade had little effect alone, the combination of CGP35348 and bicuculline produced greater increases in driven rate and expansion of the frequency response area than GABA(A) receptor blockade alone, suggesting a modulatory role of local GABA(B) receptors. The results suggest that local GABA inhibition contributes significantly to intensity and frequency coding by controlling the range of intensities over which cortical neurons operate and the range of frequencies to which they respond. The inhibitory circuits that generate nonmonotonic rate-level functions are separate from those that influence other response properties of AI neurons.     

Survey of the definition and screening of neonatal hypoglycaemia in Australia

Objective : To determine the approach to identifying neonatal hypoglycaemia and the definition of neonatal hypoglycaemia used by neonatal paediatricians in Australian Level 3 neonatal intensive care units (NICU).
Methodology : A questionnaire was sent to the 101 neonatal paediatricians in the 22 Level 3 NICU in Australia asking their method of screening for, and definition of, neonatal hypoglycaemia.
Results : Responses were received from 70 neonatal paediatricians, including all 22 directors. A bedside glucose meter is used in 19 of 22 NICU to screen for hypoglycaemia, whilst one NICU uses a glucose analyzer and another NICU uses a visual colour comparison method. One NICU does not screen, but has blood glucose measured in a satellite laboratory. If the screening method suggests hypoglycaemia, 62 of 63 neonatal paediatricians proceed to blood glucose determination in a laboratory, mostly using plasma samples. Based on the laboratory measurement, the definition of neonatal hypoglycaemia ranged from <1.1 to 3.0 mmol/L.
Conclusions : The majority of neonatal paediatricians in Australian NICU screen for neonatal hypoglycaemia using a bedside glucose meter. There is a wide range in the definition of neonatal hypoglycaemia from <1.1 to 3.0mmol/L.