General population screening for infection with Helicobacter pylori: a realistic option?

Objectives: To consider the effectiveness of a community programme of Helicobacter pylori (H pylori) screening and eradication run in collaboration with general practitioners. Specifically, to assess numbers successfully eradicating H pylori and consequently reducing the prevalence of infection, and to identify and consider areas of poor compliance.

Setting: A large general practice in Market Harborough, Leicestershire, UK.

Flow cytometric quantitation of immunofluorescence intensity: problems and perspectives. European Working Group on Clinical Cell Analysis.

Quantitation of immunofluorescence intensity serves to estimate the number of defined molecules expressed on or in cells. Clinical applications of this diagnostic tool are increasing, e.g.

Flow cytometric enumeration of CD34+ hematopoietic stem and progenitor cells. European Working Group on Clinical Cell Analysis.

The need for a rapid and reliable marker for the engraftment potential of hematopoietic stem and progenitor cell (HPC) transplants has led to the development of flow cytometric assays to quantitate such cells on the basis of their expression of CD34. The variability associated with enumeration of low-frequency cells (i.e.

Quality assessment of CD34+ stem cell enumeration: experience of the United Kingdom National External Quality Assessment Scheme (UK NEQAS) using a unique stable whole blood preparation.

CD34+ peripheral blood stem cell (PBSC) mobilization and harvesting has rapidly replaced autologous bone marrow as a source of stem cells for transplantation. Timing and adequacy of harvests rely upon the accurate enumeration of circulating CD34+ cells. However, previous EQA programmes have reported interlaboratory CVs as high as 284%, suggesting the need for greater standardization.

Determination of leucocyte antibody binding capacity (ABC): the need for standardization.

The flow cytometric determination of antigen density, or cellular antibody binding capacity, is now an accepted technique for the characterization of cells in health and disease. In HIV infection, for example, antigen density changes in CD38 expression may be an important indicator of disease progression. Our experience of using one such method, Quantum Simply Cellular, which measures antibody binding capacity (ABC), has highlighted several technical factors which can affect the results.

Reasons for non-compliance with screening for infection with Helicobacter pylori, in a multi-ethnic community in Leicester, UK.

In this study, we aimed to identify reasons for non-compliance with a screening programme for Helicobacter pylori (H pylori), in a multi-ethnic community and to assess the effectiveness of Asian language materials towards increasing compliance. A serological screening test for infection with H pylori was offered to 200 Asians and 200 non-Asians (mainly Europeans), aged 21-55 y, registered at a single general practice. Reasons for non-attendance for screening were identified by reply slip or interview.

Gene amplification as a prognostic factor in primary brain tumors.

The most reliable prognostic factors for patients with primary malignant brain tumors remain histology, age, and functional status. Management of these individuals might be improved by quantifying pertinent molecular markers. We have measured the gene dosage of the epidermal growth factor receptor (EGFR), mouse double minute 2 (MDM2), and cyclin-dependent kinase 4 (CDK4) genes in a series of brain tumor specimens and correlated their amplification status with standard prognostic factors and survival.

Relationship of Beck Depression Inventory factors to depression among adolescents.

Beck Depression Inventory (BDI) scores of 328 adolescents referred to a depression clinic were factor analyzed to test the discriminant validity of each factor. Three of the four factors (Negative Self Attitude. Performance Difficulty, and Somatic Symptoms) discriminated depressed adolescents from those with a behavior disorder or no diagnosis; the Negative Self Attitude and Performance Difficulty factors also discriminated depressed from anxious adolescents.

Glucose and phosphate toxicity in hamster preimplantation embryos involves disruption of cellular organization, including distribution of active mitochondria.

While perinuclear clustering of active mitochondria, as revealed by Rhodamine 123 staining and confocal microscopy, is part of normal hamster embryo development, it is not known whether this reorganization is necessary for development. To determine if disruption of mitochondrial organization occurs in developmentally compromised embryos, the intensity of Rhodamine 123 staining was quantitated using NIH Image Software in different regions of cultured hamster 2-cell embryos exposed to either blocking (contains glucose and phosphate) or non-blocking culture conditions. Three regions within each blastomere were defined based on the organization of freshly collected embryos: cortical (ring beneath plasma membrane), perinuclear, and intermediate regions.

Isolation and amino acid sequence of a new long-chain neurotoxin with two chromatographic isoforms (Aa el and Ae e2) from the venom of the Australian death adder (Acanthophis antarcticus).

The amino acid sequence of a previously undescribed toxin from Australian death adder venom (Acanthophis antarcticus) has been elucidated. It appears to exist in two forms which are separated by reverse-phase high-performance liquid chromatography, but which have the same sequence and mol. wt.

An optimized approach to membrane capacitance estimation using dual-frequency excitation.

We present an optimized solution to the problem of membrane impedance estimation when a patch-clamped cell is stimulated by a dual-frequency, sinusoidal excitation. The complete data set of raw whole-cell current samples is typically reduced, via digital lock-in detection, to measurements of the complex cell model admittance at the two stimulus frequencies. We describe a statistical model of both data sets and demonstrate that the admittance data adequately represent the essential features obtained from the raw data.

Single-cell measurements of quantal secretion induced by alpha-latrotoxin from rat adrenal chromaffin cells: dependence on extracellular Ca2+.

alpha-Latrotoxin (alpha-LT), from black widow spider venom, is a potent enhancer of the spontaneous quantal release of neurotransmitter from a variety of nerve terminals and clonal neurosecretory cells. Using electrochemical amperometry and estimation of membrane impedance by phase detection, we present evidence that alpha-LT induces exocytosis of catecholamines from rat adrenal chromaffin cells beginning as rapidly as 30 s after close application of the toxin. This release is largely dependent on adequate levels of extracellular Ca2+ ([Ca2+]o).

Evaluation of a novel stable whole blood quality control material for lymphocyte subset analysis: results from the UK NEQAS immune monitoring scheme.

The UK NEQAS immune Monitoring Scheme (UK NEQAS) evaluates the performance of laboratories routinely performing T-lymphocyte subset analysis on HIV-infected individuals. The scheme originally issued fresh whole blood, but a significant problem was that of analyte stability, especially 36 h postphlebotomy. To circumvent this problem, we have developed a novel stabilisation procedure that ensures retention of leucocyte light scatter and immunological staining characteristics for up to 300 days.

Self-perceptions, motivation, and school functioning of low-income maltreated and comparison children.

Maltreated children are at risk for disturbances and delays in their socioemotional and scholastic functioning. This study examined the impact of child maltreatment and age on perceptions of competence, and the relations among perceived competence, motivation, and school functioning. The sample included 76 school children living in poverty, approximately two-thirds of whom had been victims of child maltreatment.

Performance evaluation of the FACSCount System: a dedicated system for clinical cellular analysis.

Flow cytometers are instruments that can determine multiparameter data simultaneously and have a great potential in providing unique information about cells. The FACSCount System is designed as the first dedicated flow cytometer for the clinical laboratory. Its current configuration provides CD4, CD8, and CD3 absolute counts from 100 microliters of whole blood.

Translocation of active mitochondria during hamster preimplantation embryo development studied by confocal laser scanning microscopy.

The role of mitochondrial metabolism in the development of preimplantation embryos is unclear. To clarify the importance of mitochondria in early development, the fluorescent probes rhodamine 123 (Rh123: stains active mitochondrial membrane) and nonyl acridine orange (NAO: stains active and inactive mitochondrial membrane) were used with confocal laser scanning microscopy to study the distribution of mitochondria in hamster unfertilized follicular and oviductal eggs (11.5 hr and 16 hr post-hCG, respectively) and preimplantation embryos (1-cell to blastocyst).

Inhibitory effect of glucose and phosphate on the second cleavage division of hamster embryos: is it linked to metabolism?

Hamster embryos cannot complete the second cleavage division in vitro in the presence of glucose and inorganic phosphate (Glu/Pi). Embryos can recover from an 8 h (12:30-20:30 h) exposure to Glu/Pi, although cleavage is retarded by 10 h and continued development to the blastocyst stage is rare (2%). The vulnerability of 2-cell embryos to Glu/Pi changes during the cell cycle, being greatest just prior to cleavage which occurs at approximately 21:00 h: exposure to Glu/Pi from 12:30-14:30 h allowed 94% development to morulae/blastocysts while exposure from 18:30-20:30 h decreased morula/blastocyst development to 48%.

Voltage-dependent Na+ and Ca2+ currents in human pancreatic islet beta-cells: evidence for roles in the generation of action potentials and insulin secretion.

We describe three voltage-dependent inward currents in human pancreatic beta-cells. First, a rapidly inactivating Na+ current, blocked by tetrodotoxin (TTX) is seen upon brief depolarization to or beyond -40 mV. Second, a transient, low-voltage-activated (LVA), amiloride-blockable Ca2+ current is seen upon depolarization to or beyond -55 mV; it inactivates within less than 1s of sustained depolarization to -40 mV.