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.

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.

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.

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.

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)

'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.

Suppression of synthesis and esterification of cholesterol and stimulation of low density lipoprotein receptor activity by polyoxyethylated cholesterol in cultured human fibroblasts.

In cultured skin fibroblasts from normal and homozygous familial hypercholesterolemic subjects, a water-soluble polyoxyethylated derivative of cholesterol suppresses the incorporation of [2-14C]acetate into cholesterol and decreases the activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase, the rate-limiting enzyme of cholesterol synthesis. The effect of this compound on low density lipoprotein (LDL) receptor-mediated activities (binding, internalization, and degradation of LDL) and on cholesterol ester formation was compared to that of LDL and 25-hydroxycholesterol. In normal fibroblasts preincubated in lipoprotein-deficient serum, LDL or 25-hydroxycholesterol decreased cholesterol synthesis and LDL receptor activity and increased cholesterol ester formation. In contrast, polyoxyethylated cholesterol stimulated LDL receptor activity, inhibited cholesterol ester formation mediated by LDL and 25-hydroxycholesterol, and inhibited the activity of acyl-CoA:cholesterol acyltransferase in cell extracts. Polyoxyethylated cholesterol had no effect on the low level of LDL receptor activity of homozygous hypercholesterolemic fibroblasts but stimulated the half-normal activity of heterozygous cells.

Proton nuclear magnetic resonance study of cobrotoxin.

Cobrotoxin (Mr 6949), which binds tightly to the acetylcholine receptors, contains no phenylalanines and only two histidines, two tyrosines, and one tryptophan that result in well-resolved aromatic proton resonances in D2O at 360 MHz. His-32, Tyr-25, and the Trp are essential for toxicity and may interact with the acetylcholine receptor. We assign two titratable resonances (pKa = 5.1) at delta = 9.0 and 7.5 ppm at pH 2.5 and at 7.7 and 7.1 ppm at pH 9.5 to the C-2 and C-4 ring protons, respectively, of His-4. Two other titratable resonances (pKa = 5.7) at delta = 8.8 and 6.9 ppm at pH 2.5 and at 7.8 and 6.7 ppm at pH 9.5 are assigned to the C-2 and C-4 ring protons of His-32, respectively. The differences in delta values of the two histidines reflect chemically different microenvironments while their low pKa values could arise from nearby positive charges. A methyl resonance gradually shifts upfield to delta approximately 0.4 ppm as His-4 is deprotonated and is tentatively assigned to the methyl group of Thr-14 or Thr-15 which, from published X-ray studies of neurotoxins, are located in the vicinity of His-4. Further, we have identified the aromatic resonances of the invariant tryptophan and individual tyrosines and the methyl resonance of one of the two isoleucines in the molecule. Several broad nontitrating resonances of labile protons which disappear at pH greater than 9 may arise from amide groups of the beta sheet in cobrotoxin.

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.