Count rate limitations for pulse-counting instrumentation in pulsed accelerator fields

This paper discusses various concepts involved in the counting losses of pulse-counting health physics instrumentation when used within the pulsed radiation environments of typical accelerator fields in order to preestablish appropriate limitations in use. Discussed are the "narrow" pulse and the "wide" pulse cases, the special effect of neutron moderating assemblies, and the effect of pulse fine microstructure on the counting losses of the pulse-counting instrumentation. In the narrow-pulse case, the accelerator pulse width is less than or equal to the instrument's dead time; whereas in the wide-pulse case, the accelerator pulse width is significantly longer than the instrument's dead time. Examples are provided that highlight the various concepts and limitations.     

A novel form of short QT syndrome (SQT3) is caused by a mutation in the KCNJ2 gene

Short QT syndrome (SQTS) leads to an abbreviated QTc interval and predisposes patients to life-threatening arrhythmias. To date, two forms of the disease have been identified: SQT1, caused by a gain of function substitution in the HERG (I(Kr)) channel, and SQT2, caused by a gain of function substitution in the KvLQT1 (I(Ks)) channel. Here we identify a new variant, "SQT3", which has a unique ECG phenotype characterized by asymmetrical T waves, and a defect in the gene coding for the inwardly rectifying Kir2.1 (I(K1)) channel. The affected members of a single family had a G514A substitution in the KCNJ2 gene that resulted in a change from aspartic acid to asparagine at position 172 (D172N). Whole-cell patch-clamp studies of the heterologously expressed human D172N channel demonstrated a larger outward I(K1) than the wild-type (P<0.05) at potentials between -75 mV and -45 mV, with the peak current being shifted in the former with respect to the latter (WT, -75 mV; D172N, -65 mV). Coexpression of WT and mutant channels to mimic the heterozygous condition of the proband yielded an outward current that was intermediate between WT and D172N. In computer simulations using a human ventricular myocyte model the increased outward I(K1) greatly accelerated the final phase of repolarization, and shortened the action potential duration. Hence, unlike the known mutations in the two other SQTS forms (N588K in HERG and V307L in KvLQT1), simulations using the D172N and WT/D172N mutations fully accounted for the ECG phenotype of tall and asymmetrically shaped T waves. Although we were unable to test for inducibility of arrhythmia susceptibility due to lack of patients' consent, our computer simulations predict a steeper steady-state restitution curve for the D172N and WT/D172N mutation, compared with WT or to HERG or KvLQT1 mutations, which may predispose SQT3 patients to a greater risk of reentrant arrhythmias.     

Surgical treatment of inspissated bile syndrome using a 2-stage pure laparoscopic approach: A case report

We describe a 99-day old girl with inspissated bile syndrome (IBS) unresponsive to treatment with oral ursodeoxycholic acid. We performed a pure laparoscopic 2-stage procedure, consisting of cholecystostomy and insertion of an indwelling balloon catheter for local ursodeoxycholic acid flushing for 13 consecutive days. Subsequently, the cholecystostomy was removed, preserving the gallbladder using the same laparoscopical approach when bilirubin values returned to normal and bile duct obstruction was no longer detectable radiologically. This is the first report of an exclusively laparoscopic management of IBS.     

Is non-union of tibial shaft fractures due to nonculturable bacterial pathogens? A clinical investigation using PCR and culture techniques

ABSTRACT: BACKGROUND: Non-union continues to be one of the orthopedist's greatest challenges. Despite effective culture methods, the detection of low-grade infection in patients with non-union following tibial fracture still presents a challenge. We investigated whether "aseptic" tibial non-union can be the result of an unrecognized infection. METHODS: A total of 23 patients with non-union following tibial shaft fractures without clinical signs of infection were investigated. Intraoperative biopsy samples obtained from the non-union site were examined by means of routine culture methods and by polymerase chain reaction (PCR) for the detection of 16 S ribosomal RNA (rRNA). Control subjects included 12 patients with tibial shaft fractures. RESULTS: 23 patients (8 women and 15 men; mean age: 47.4 years) were included into this study. Preoperative C-reactive protein levels (mean: 20.8 mg/l) and WBC counts (mean: 8,359/ul) in the study group were not significantly higher than in the control group. None of the samples of non-union routine cultures yielded microorganism growth. Bacterial isolates were found by conventional culturing methods in only 1 case of an open fracture from the control group. In this case, PCR yielded negative results. 16 S rRNA was detected in tissue specimens from 2 patients (8.7%) with non-union. The analysis of these variable speciesspecific sequences enabled the identification of specific microorganisms (1x Methylobacterium species, 1x Staphylococcus species). Both PCR-positive patients were culture-negative. CONCLUSIONS: The combination of microbiological culture and broad-range PCR seems to substantially add to the number of microbiological diagnoses obtained and may improve the clinican's ability to tailor therapy to the individual patient's needs.     

The ups and downs of Parkinson disease: a prospective study of mood and anxiety fluctuations.

BACKGROUND: Parkinson disease (PD) patients with motor fluctuations experience mood fluctuations, but studies have been limited in number and methodology. OBJECTIVES: To better understand the phenomenology of mood, anxiety, and motor fluctuations in PD. METHOD: Eighty-seven PD patients and 19 spouse controls completed questionnaires, rating scales, and diaries using visual analogue scales (VAS) to rate mood, anxiety, and motor states. Average daily variance in VAS scores was determined, and PD patients whose average daily variance was larger than that for all of the control subjects were considered to have fluctuations. RESULTS: Twenty-nine percent of patients had fluctuations in anxiety, 24% motor, and 21% mood; 65% had no fluctuations. Seventy-five percent of patients with motor fluctuations had mood and/or anxiety fluctuations, but 5 subjects reported emotional fluctuations without motor fluctuations. The combination of mood and anxiety fluctuations was frequent, but anxiety and mood did not always appear to fluctuate together. Visual inspection of diaries revealed that not all patients exhibited a temporal relationship between emotional and motor fluctuations. Compared with nonfluctuators, those with mood or anxiety fluctuations were more likely to have higher scores on psychiatric rating scales, report histories of depression or anxiety, and use psychotropic medications. CONCLUSIONS: PD patients are heterogeneous with regard to the presence, range, and pattern of fluctuations. In general, patients with mood fluctuations also have anxiety fluctuations.     

Mild early life stress enhances prefrontal-dependent response inhibition in monkeys.

BACKGROUND: Severely stressful early experiences have been implicated in the pathophysiology of psychiatric disorders. In contrast, exposure to mild early life stress (i.e., stress inoculation) strengthens emotional and neuroendocrine resistance to subsequent stressors. Herein we extend this research to examine the effects of mild early life stress on cognition. METHODS: Squirrel monkeys were randomized to a mild intermittent stress (IS; n = 11) or nonstress (NS; n = 9) condition from 17 to 27 weeks postpartum. At 1.5 years of age, monkeys were assessed for response inhibition on a test previously shown to reflect prefrontal-dependent cognitive function. RESULTS: IS monkeys demonstrated fewer response inhibition errors compared with NS monkeys. There were no rearing-related differences in aspects of performance that did not require inhibitory control. Compared with NS monkeys, IS monkeys had lower basal plasma pituitary-adrenal stress hormone levels. No rearing-related differences on neuroendocrine measures obtained 15 minutes after testing were found. CONCLUSIONS: Results from this experiment provide the first evidence that exposure to mildly stressful early experiences improves prefrontal-dependent response inhibition in primates. Combined with our previous data, findings from this animal model suggest that exposure to mild early life stress may enhance the development of brain systems that regulate emotional, neuroendocrine, and cognitive control.     

Establishment of an enzyme-linked immuno-sorbent assay for urinary trypsin inhibitor by using a monoclonal antibody.

Monoclonal antibodies against inter-alpha-trypsin-inhibitor (ITI) were produced. One clone showing specificity for urinary trypsin inhibitor (UTI), a proteolytic fragment of ITI, which is excreted into urine, was selected for the establishment of an enzyme-linked immuno-sorbent assay (ELISA). The ELISA for the quantification of UTI was shown to work reproducibly in the range between 0.5 and 10 ng UTI/ml urine. Urines of several patients suffering from different lung diseases were screened for UTI using the established ELISA. Highest UTI levels were found in the urine of patients with lung empyema. A more moderate increase was observed in patients suffering from lung tuberculosis and from secondary and primary lung tumors.