Timely thoracoscopic decortication promotes the recovery of paediatric parapneumonic empyema.

INTRODUCTION: Parapneumonic empyema is one of the most commonly encountered yet difficult to manage paediatric thoracic conditions. Conservative treatment with chest tube drainage and fibrinolytic agents had been proposed but operative decortication remains the gold standard for refractory cases. Thoracoscopic decortication has been advocated in recent years due to its superiority in terms of post-operative pain, cosmesis and other long-term results. However, few studies investigated the effect of timing on peri-operative outcomes. This study aims to explore the benefits of early decortication. METHODS: Retrospective study of all patients who underwent thoracoscopic decortication between 1999 and 2013 at a tertiary referral centre was performed. Data were extracted from respective medical records. Patients' demographics, peri-operative outcomes, length of hospitalization and post-operative complications were analysed. RESULTS: A total of 28 patients were identified, 12 males and 16 females. Average age of patients was 4.5 years (range 12 months-14 years). Right-sided empyema was involved in 14 of the patients. Patients who underwent operation within 2 weeks from symptom onset (n = 16) showed significant shorter post-operative hospital stay (mean 9.5 vs 20.4 days, p = 0.003) and total hospitalization duration (mean 19.3 vs 38.8 days, p < 0.001). Correlation study demonstrated a strong relation between delay in operation and prolonged hospitalization (r = 0.63, p = 0.001). The peri-operative and post-operative outcomes were similar. No major post-operative complication was encountered except one patient who required a second decortication for residual empyema. CONCLUSION: Thoracoscopic decortication is a safe and feasible procedure for parapneumonic empyema. Timely surgery is recommended as it promotes early recovery and shorter hospitalization.

Differential-phase-shift quantum key distribution using heralded narrow-band single photons.

We demonstrate the first proof of principle differential phase shift (DPS) quantum key distribution (QKD) using narrow-band heralded single photons with amplitude-phase modulations. In the 3-pulse case, we obtain a quantum bit error rate (QBER) as low as 3.06% which meets the unconditional security requirement. As we increase the pulse number up to 15, the key creation efficiency approaches 93.4%, but with a cost of increasing the QBER. Our result suggests that narrow-band single photons maybe a promising source for the DPS-QKD protocol.

Suppression of 3-hydroxy-3-methylglutaryl coenzyme A reductase activity and of incorporation of acetate into cholesterol in homozygous hypercholesterolemic fibroblasts by ferritin-low density lipoprotein conjugates.

Conjugates of ferritin with low density lipoproteins (LDL) were prepared and separated by sucrose gradient centrifugation. These conjugates, at cholesterol concentration of 100--132 microgram/ml, caused a greater than 90% suppression of hydroxymethylglutaryl coenzyme A reductase activity and of acetate incorporation into cholesterol in cultured skin fibroblasts from a normal subject as well as from a subject with homozygous familial hypercholesterolemia. The half maximal inhibition concentration was approx. 10 microgram/ml cholesterol for LDL and ferritin . (LDL)2 and 5 microgram/ml for (ferritin)2 . LDL in both cell lines. In contrast, native low density lipoproteins have only a minimal inhibitory effect in homozygous cells. The ability of the conjugates to stimulate the incorporation of oleate into cholesteryl esters was also equal in the two cell lines, although the conjugates were only 10% as active as low density lipoproteins in the normal cells. LDL reduced the ferritin . (LDL)2-mediated suppression of hydroxymethylglutaryl-CoA reductase activity in homozygous cells while ferritin . (LDL)2 reduced the LDL-mediated stimulation of cholesteryl ester formation in normal cells.

The effects of triiodothyronine, hydrocortisone and insulin on lipid synthesis by cultured fibroblasts preincubated in a serum-free medium.

Studies of lipid metabolism in cell cultures are usually carried out after preincubation of cells in media containing lipoprotein-deficient or delipidated serum. The artifacts produced during delipidation prevent the standardization of assays and the study of the role of hormones on lipid metabolism. We studied the effects of triiodothyronine, hydrocortisone, insulin and their combination on cholesterol and fatty acid synthesis in cultured human skin fibroblasts preincubated for 24 h in an artificial medium (medium A) consisting of equal volumes of Dulbecco's modified Eagle's and Ham's F-12 media enriched with transferrin, biotin and calcium pantothenate. In cells preincubated in medium A the incorporation of acetate to cholesterol and the activity of hydroxymethylglutaryl-coenzyme A (HMG-CoA) reductase were much lower than in cells preincubated in standard medium containing lipoprotein-deficient serum. Addition of the three hormones caused a marked stimulation of the incorporation of acetate to cholesterol (from 3.1 to 17.7 pmol/min per mg protein), an activity similar to that in cells preincubated in lipoprotein-deficient serum plus hormones. The stimulatory effect of the hormones on HMG-CoA reductase activity was smaller, from 11 to 26 pmol/min per mg protein compared to 83 pmol/min per mg protein in cells preincubated in lipoprotein-deficient serum plus hormones. Most of the stimulatory effect was due to insulin. The lack of coordinate response between these two parameters in cells preincubated in artificial medium could not be explained by (a) stimulation of a post-mevalonate step as measured by the incorporation of mevalonate to cholesterol; (b) the in vitro inactivation of HMG-CoA reductase by phosphorylation: incubation of fibroblast microsomes with Escherichia coli alkaline phosphatase resulted in a decrease in HMG-CoA reductase activity, in contrast to an increase in hepatic microsomes; (c) the presence of inhibitors of HMG-CoA reductase in the microsomal extract. In cells preincubated in medium A the incorporation of acetate to fatty acids and the activities of acetyl-CoA carboxylase and fatty acid synthetase were approximately equal to that of cells preincubated in standard medium containing lipoprotein-deficient serum. Hormones added to medium A caused a stimulation of incorporation of acetate to fatty acids (from 5.1 to 19.8 pmol/min per mg protein), the activity of acetyl-CoA carboxylase (from 494 to 820 pmol/min per mg protein) and of fatty acid synthetase (from 300 to 678 pmol/mg protein). These values were significantly higher than those obtained in cells preincubated with lipoprotein-deficient serum with or without hormones.(ABSTRACT TRUNCATED AT 400 WORDS)

Laboratory suggestion. Interpretation of plasma protamine paracoagulation test.

The reliability of the plasma protamine paracoagulation test has been questioned because of the controversy surrounding its interpretation and because of false positives reported with high frequency in some series. To minimize the frequency of false positives, it is recommended that when the test is done at room temperature, clot or fibrin strand formation be considered a positive result and precipitates be considered negative. Use of the wire hook to distinguish fibrin strands from precipitates is suggested. Nascent clotting and blood drawn from indwelling catheters should be avoided.

Permanent records of microchromatography of hemoglobins.

In the general hematology laboratory, quantitation of hemoglobin A2 by the microchromatographic method is superior to the method of elution from cellulose acetate membranes. A permanent record of microchromatographic patterns for the detection of hemoglobins S and C at birth can be easily obtained by using a photocopying machine and a flat mirror. These copies can be stored for comparison with definitive results when the children are retested at 6 months of age or later.

Actin-positive spindle cell lymphoma.

We report an unusual case of malignant lymphoma, large noncleaved B-cell type, exhibiting sarcomatoid and myxoid patterns and strong positive staining for muscle-specific actin. Despite vigorous chemotherapy, the 64-year-old male patient, who had lymphoma involving his right inguinal area, retroperitoneum, and anterior chest wall at the time of presentation, died 3 months later.

'Rhabdoid' Wilms' tumor: an ultrastructural study.

We studied a 5-week-old infant who had a "rhabdoid" Wilms' tumor. Ultrastructural studies disclosed aggregates of cytoplasmic filaments that seemed to correspond with the eosinophilic cytoplasmic bodies seen by light microscopy, but did not uncover evidence of rhabdomyoblastic differentiation. The histogenesis of this subtype was not established, but origin from the metanephric blastema could not be ruled out.

Postoperative spindle-cell nodule of urinary bladder with unusual intracytoplasmic inclusions.

Postoperative spindle-cell nodule of the urinary bladder (or in the absence of previous surgical procedure, inflammatory pseudotumor) is a reactive process of unknown etiology mimicking a sarcoma. Intracytoplasmic inclusion bodies were noted inside the atypical spindle cells on Diff-Quik stained smears in a recent case of this entity. Although fluorescence was noted in the inclusion bodies with monoclonal antibodies against the major outer membrane protein of the Chlamydia species, the exact nature of these inclusion bodies remains unknown.

Simple BASIC program for calculating the cervicovaginal FNP and for estimating the sample size of the number of cervicovaginal smears to be rescreened.

OBJECTIVE: To guide cytotechnologists and pathologists in calculating the false negative proportion, or rate, and the number of Papanicolaou smears to be reevaluated for a meaningful assessment of screening performance, a computer program written in BASIC was prepared, based on several recent publications in the field of cytopathology. RESULTS: A complete program listing and sample runs to help users be cognizant of the necessary inputs to run the program. The output from the program gives the results of the various calculations. CONCLUSION: Since the tedious manual calculations are handled by the computer program, it is more likely for those involved in the interpretation of Papanicolaou smears to follow the approaches suggested by experts in these two areas.