I.v. melphalan in carcinoma of the lung: effect of cyclophosphamide priming on hematopoietic toxicity

Thirty-six patients with lung cancer, 24 with prior chemotherapy and 12 without prior chemotherapy, received iv melphalan at doses ranging from 20 to 40 mg/m2 of body surface area. Patients who showed moderate myelosuppression and remained in the study were also investigated to determine if cyclophosphamide (300 mg/m2) administered 1 week before the identical dose of i.v. melphalan modified the hematopoietic toxicity of melphalan (cyclophosphamide priming). In this study, the activity of melphalan was minimal, four minor responses with no partial or complete responses. Three of these minor responses were in previously untreated patients. The major toxicity was hematopoietic and the maximum tolerated i.v. dose was 20 mg/m2 in the patients previously treated with chemotherapy and 30 mg/m2 in those without prior chemotherapy. Cyclophosphamide priming did not reduce the myeloid toxicity. Myelosuppression was more severe in the course that included cyclophosphamide. Recovery, however, appeared to be similar in both courses. I.v. melphalan at these doses has minimal activity in lung cancer. Cyclophosphamide administered 1 week before i.v. melphalan does not decrease the myelosuppression but should be investigated further for its effect on the rate of wbc and neutrophil count recovery.     

The relationship between smoking status and serious psychological distress: findings from the 2007 Behavioral Risk Factor Surveillance System

Objectives:  

To examine the associations between smoking and quit attempts with psychological distress and also by socioeconomic groups.     

Study of serum adenosine deaminase (ADA) and ascorbic acid levels in recurrent tonsillitis

A biochemical study consisting of estimation of serum adenosine deaminase and ascorbic acid was carried out in 20 patients of recurrent tonsillitis (i) during the acute attack, (ii) after medical treatment and (iii) after tonsillectomy. These parameters were compared with a control group of 20 healthy individuals. The study revealed significant decrease of ADA and ascorbic acid levels during acute stage of recurrent tonsillitis, and subsequent recovery after medical treatment and tonsillectomy. Levels of ascorbic acid were similarly reflected. In the acute stage of recurrent tonsillitis, tonsils, instead of acting as protective barriers, appear to become a source for the breakdown of immunological mechanism.     

Controlled FiO2 Therapy to Neonates by Oxygenhood in the Absence of Oxygen Analyzer

Background

A study was conducted to evaluate a system of standardizing the oxygen concentration inside the oxygen hood and to develop guidelines for controlled FiO₂ administration by changing size of the hood, lid position on the hood and the oxygen flow rate, without an oxygen analyzer. The effect of low flow rates on carbon dioxide (CO₂) retention was also studied.

Method

A dummy patient and thirty neonates, requiring oxygen to be delivered through head box, constituted the material for the study group. Oxygen content in the head box was measured using a standard oxygen analyzer while the size of head box, flow rate and lid position were changed independently and in combination. The head boxes were tested on a dummy patient. These results were analyzed, and applied to thirty neonates requiring oxygen therapy using a head box.

Result

Volume of headbox had an inverse relation with the oxygen concentration inside the headbox and smaller sized headbox achieved more predictable oxygen concentration at all flow rates. Maximum difference in oxygen concentration by varying the lid position was seen in the large headbox. Keeping the variables constant, oxygen concentration was significantly lower in babies as compared to dummy. No significant CO₂ retention was found at a flow rate of four litres per minute (lpm) in small and three lpm in a medium and large head box respectively, while lower flow rates were associated with CO₂ retention.

Conclusion

It is possible to predict the oxygen concentration inside the head box without the use of oxygen analyzer. Larger head box and higher lid position, results in lower oxygen concentration, at a given oxygen flow rate. Oxygen concentration achieved in babies is lesser than the concentration achieved in a dummy. Flow rates of less than four lpm in small and three lpm in medium and large sized head boxes are associated with CO₂ retention. These results are not applicable to infants weighing less than 2 kg.Key Words: Neonates, Oxygen therapy, Oxygen hood, Oxygen concentration, Oxygen analyzer     

Effect of zinc added to multi-vitamin supplementation containing low-dose vitamin A on plasma retinol level in children--a double-blind randomized, controlled trial

In a community-based double-blind randomized trial in children aged 6-35 months, both intervention and control groups received a multi-vitamin syrup containing vitamin A, while the intervention group had zinc gluconate (equivalent to 10 mg of elemental zinc) additional in the syrup. There was a significant decrease in diarrhoea and pneumonia in the intervention group. This study was undertaken to investigate if addition of zinc to vitamin A had improved plasma retinol levels, which, in turn, was responsible for the effects observed in the intervention group. In a randomly-selected subsample of 200 children--100 each from the intervention and the control group, plasma retinol levels after 120 days of supplementation were measured. There was no difference in the mean plasma retinol levels [the difference in the mean 0.46 microg/dL (95% confidence interval -1.42-2.36)] between the two groups following supplementation. No difference in plasma retinol levels was observed in the subgroups based on base-line nutritional status and plasma zinc levels. Addition of zinc to low-dose vitamin A in this study did not improve the vitamin A status of children and cannot explain morbidity effects of the intervention.     

Hypothermia in the management of traumatic brain injury. A systematic review and meta-analysis

Objective Brain injury remains the leading cause of death in cases of trauma in North America and Europe. This article critically appraised and summarised all published and peer-reviewed, randomised, controlled trials of the use of hypothermia in traumatic brain injury.Design To be included, a study had to be a published, randomised, controlled trial of the use of hypothermia in the management of traumatic brain injury. Pooling of data and meta-analysis of results occurred.Setting Conducted at a tertiary level Canadian teaching hospital.Patients and participants Patients were combined from eight randomised, controlled trials to generate a population of 748 severely head-injured patients.Measurements and results Eight studies provided data on the efficacy of hypothermia in the management of traumatic brain injury. The pooled odds ratio of mortality in the hypothermic group was 0.81 (95%CI =0.59–1.13, p=0.22). The OR of a poor neurological outcome (GOS 1,2 or 3) was 0.75 (95% CI=0.56–1.01, p=0.06). The odds ratio for pneumonia in the normothermic group was 0.42 (95%CI =0.25–0.70, p=0.001).Conclusions Although meta-analysis suggests that iatrogenic hypothermia may confer a marginal benefit in neurological outcome, there does not appear to be clear evidence of lower mortality rates in unselected traumatic brain injury patients. Prolonged hypothermia may confer a benefit, particularly in patients with elevated intracranial pressure refractory to conventional manipulations. Conclusions regarding the use of hypothermia are controversial and not strongly supported by the available evidence.     

The electrophysiological effects of ouabain on sinus node and atrium in man.

Electrophysiological studies were performed in 16 patients before and 30 min after intravenous administration of ouabain (0.1 mg/kg). P-A interval (mean+/-SEM) was 40+/-2.1 ms before and 44+/- 1.5 ms after ouabain (P less than 0.001). Atrial effective and functional refractory periods (ERP and FRP) were measured in all patients during sinus rhythm and during driving at equivalent paced rates in 12 patients. The mean atrial ERP and FRP during sinus rhythm were, respectively, 244+/-10.5 and 307+/-11.0 ms before and 253+/-9.7 and 318+/-11.4 ms after infusion of ouabain (NS). Mean atrial ERP and FRP during driving were, respectively, 231+/-15.3 and 264+/-14.9 ms before and 266+/-18.6 and 296+/-19.7 ms after ouabain (P less than 0.01 and P less than 0.01). Mean sinus cycle length and sinus recovery times were, respectively, 887+/-31.2 and 1,113+/-38.7 ms before and 905+/-38.2 and 1,008+/-30.7 ms after infusion of ouabain (NS and P less than 0.005). Calculated sinoatrial conduction times before and after ouabain were 90+/-6.8 and 110+/-8.5 ms, respectively (P less than 0.005). In summary, ouabain produced depression of intraatrial conduction as manifested by increase in P-A interval and atrial effective and functional refractory periods. Ouabain significantly increased calculated sinoatrial conduction time without significant effect on spontaneous sinus cycle length.     

Treadmill exercise testing in the Wolff-Parkinson-White syndrome

Graded treadmill exercise testing was performed in 54 patients with the Wolff-Parkinson-White syndrome and preexcitation (persistent in 36, intermittent in 9 and concealed in 9). Forty-eight patients had previous paroxysmal supraventricular arrhythmia (spontaneous or induced or both). At initiation of treadmill testing, the nine patients with intermittent and the nine with concealed preexcitation had normal conduction. None manifested preexcitation during exercise. Thirty-six patients had preexcitation at initiation of exercise; exercise produced no change in preexcitation in 2, partial normalization of the QRS complex in 16 (due to enhanced atrioventricular [A-V] nodal conduction), and total normalization of the QRS complex in 18 (due to enhanced A-V nodal conduction in 14 and to rate-dependent anomalous pathway block in 4). Exercise-provoked block of the anomalous pathway reflected prolonged anomalous pathway refractoriness, as measured with atrial stimulation. All 18 patients with either total or partial preexcitation at peak exercise manifested more than 1 mm flat or downsloping S-T segment depression. None had evidence of ischemic heart disease. None of the 54 patients manifested either paroxysmal supraventricular tachycardia or atrial fibrillation during or after treadmill exercise.Treadmill exercise testing in patients with preexcitation frequently produces partial or total normalization of the QRS complex due to enhanced A-V nodal conduction and, less commonly, total normalization due to rate-dependent block of the anomalous pathway. False positive S-T segment changes (suggesting ischemia) are always present in patients manifesting preexcitation during treadmill testing. Treadmill exercise testing in patients with preexcitation does not provoke paroxysmal supraventricular tachycardia or atrial fibrillation and is not useful as a provocative test for arrhythmia.     

Implicit Bias in Pediatric Academic Medicine

Objective

Despite known benefits of diversity, certain racial/ethnic groups remain underrepresented in academic pediatrics. Little research exists regarding unconscious racial attitudes among pediatric faculty responsible for decisions on workforce recruitment and retention in academia. This study sought to describe levels of unconscious racial bias and perceived barriers to minority recruitment and retention among academic pediatric faculty leaders.