Internal quality assurance in a clinical virology laboratory. I. Internal quality assessment.

AIMS--In April 1991 an internal quality assessment scheme (IQAS) was introduced into the virology section of the Clinical Microbiology and Public Health Laboratory, Cambridge. The IQAS was established to identify recurring technical and procedural problems, to check the adequacy of current techniques, and to calculate the frequency of errors. METHODS--Between April 1991 and December 1993, 715 anonymous clinical serum samples were submitted to the laboratory to test 3245 individual procedures of diagnostic viral serology. RESULTS--A total of 485 (14.9%) procedural and 61 (1.9%) technical discrepancies were observed, the technical discrepancies mainly being recorded in complement fixation tests. Twenty two (0.7% of total procedures) of the technical discrepancies were diagnostically significant. CONCLUSIONS--Evaluation criteria developed with the introduction of IQAS to viral serology, and technical and procedural discrepancies are assessed. As yet, IQAS has not been introduced to other sections of the diagnostic virology laboratory (virus isolation, electron microscopy, immunofluorescence, and enzyme linked immunosorbent assays for viral and chlamydial antigens).     

Internal quality assurance in a clinical virology laboratory. II. Internal quality control.

AIMS--In April 1991 additional quality control procedures were introduced into the virology section of the Clinical Microbiology and Public Health Laboratory, Cambridge. Internal quality control (IQC) samples were gradually included in the serological assays performed in the laboratory and supplemented kit controls and standard sera. METHODS--From April 1991 to December 1993, 2421 IQC procedures were carried out with reference sera. RESULTS--The IQC samples were evaluated according to the Westgard rules. Violations were recorded in 60 of 1808 (3.3%) controls and were highest in the IQC samples of complement fixation tests (25/312 (8%) of controls submitted for complement fixation tests). CONCLUSIONS--The inclusion of IQC samples in the serological assays performed in the laboratory has highlighted batch to batch variation in commercial assays. The setting of acceptable limits for the IQC samples has increased confidence in the validity of assay results.     

Antiphospholipid antibodies (APA) and recurrent pregnancy loss: treating a unique APA positive population

Dear Sir, We read the recent article by Franklin and Kutteh (2002), concerningthe pregnancy outcomes of recurrent pregnancy loss (RPL) patientswho had normal obstetrical evaluations with the exception ofpositive antiphospholipid antibodies (aPL) findings. In theirreport distinctions were made between two groups of aPL positiveRPL patients with reference to their aPL specificities. Group1 patients had ‘the common’ aPL, anticardiolipin(aCL), or antiphosphatidylserine antibodies (aPS) and/or a lupusanticoagulant (LAC). For comparisons,     

Health expenditure and finance: who gets what?

The methods used in South Africa's first comprehensive review of health finance and expenditure are outlined. Special measures were adopted to make the process acceptable to all concerned during a period of profound political transition. The estimation of indicators of access to public sector resources for districts sorted by per capita income allowed the health care problems of disadvantaged communities to be highlighted.     

LPS-Induced NF-kappaB activation and TNF-alpha release in human monocytes are protein tyrosine kinase dependent and protein kinase C independent

BACKGROUND: Tumor necrosis factor alpha (TNF-alpha) is an important mediator of septic shock. Endotoxin (LPS) signal transduction in human monocytes leads to activation of nuclear factor-kappa B (NF-kappaB) and TNF-alpha release. Previous studies have implicated activation of both protein kinase C (PKC) and protein tyrosine kinases (PTK) in LPS-induced NF-kappaB activation and TNF-alpha production. We hypothesized that inhibition of either PKC or PTK would decrease LPS-induced NF-kappaB DNA binding and TNF-alpha release in human monocytes. MATERIALS AND METHODS: Human monocytes were stimulated with PMA (50 ng/ml) alone or LPS (100 ng/ml) with and without a nonspecific serine/threonine protein kinase inhibitor staurosporine (Stauro), a specific pan-PKC inhibitor bisindolylmaleimide (Bis), or an inhibitor of PTK genistein (Gen). TNF-alpha release in culture supernatants was measured by an ELISA. NF-kappaB DNA binding was evaluated by electrophoretic mobility shift assay. RESULTS: LPS increased NF-kappaB DNA binding and TNF-alpha release in human monocytes. Nonspecific protein kinase inhibition inhibited NF-kappaB activation and TNF-alpha release, while specific PKC inhibition with Bis had no effect on LPS-induced NF-kappaB DNA binding or TNF-alpha release. PTK inhibition with Gen attenuated both LPS-induced NF-kappaB DNA binding and TNF-alpha production in human monocytes. Direct activation of PKC with PMA induced both NF-kappaB activation and TNF-alpha production by human monocytes. CONCLUSIONS: These results suggest that LPS-induced NF-kappaB activation and TNF-alpha release in human monocytes are independent of PKC activity. Furthermore, our results provide evidence that PTK plays a role in LPS-induced NF-kappaB activation and TNF-alpha release in human monocytes and thus could be a potential therapeutic target in inflammatory states.     

Angiotropic large B-cell lymphoma with clinical features resembling subacute combined degeneration of the cord

Angiotropic large cell lymphoma is a rare neoplastic disorder associated with a high mortality. The hallmark of the disease is lymphoid proliferation confined to the intravascular compartment without local tissue or vessel wall infiltration [1]. This feature is so striking that the disease was originally thought to arise from endothelial tissue and early cases were described as malignant angioendotheliomatosis. However, application of immunohistochemical methods for detection of lymphoid markers such as the CD45 and CD20 cell surface markers has confirmed its lymphoid origin, usually of B-cell lineage [2]. Clinical manifestations of the disease are protean and are due to multifocal medium and small vessel occlusion by tumour cells [3]. Characteristic sites of involvement are skin and central nervous system and although an ante-mortem diagnosis can be made from a biopsy specimen, it is often unsuspected [4]. We present a case of angiotropic large B-cell lymphoma in a 74-year-old man who presented with urinary symptoms and had a neurological picture resembling subacute combined degeneration of the cord.     

Monoclonal antibodies to human melanoma-associated antigens: an amplified enzyme-linked immunosorbent assay for the detection of antigen, antibody, and immune complexes

An amplified, indirect biotin-avidin micro-enzyme-linked immunosorbent assay was developed for the measurement of human melanoma-associated antigens, either free or circulating with associated immunoglobulin in patient sera. Parameters and specificity of detection were assessed using monoclonal antibody to human melanoma-associated antigens. The main advantages of the assay are its flexibility, through the use of indirect detection and a variety of formats, and its sensitivity, with a lower limit of antibody detection at 100 pg/well and a lower limit of soluble antigen detection at 10 pg/well. The assay was applied to cell surface antigen detection with monoclonal antibody 9.2.27 to a melanoma-associated antigen against a panel of glutaraldehyde-fixed cells, and gave similar binding specificity as assessed by a previous 125I-Protein A assay. Utilizing a unique "sandwich" format, aMr 100,000 melanoma-carcinoma-associated antigen was quantitated in melanoma patient sera and found highly elevated in Stage IV disease. The same sandwich format was also used to detect and determine the class of human immunoglobulin associated with circulating Mr 100,000 human melanoma-associated antigens in normal donor sera. Thus, the sensitivity and flexibility of this enzyme-linked immunosorbent assay system make it particularly suitable for numerous applications in the study of monoclonal antibody-defined tumor-associated antigens.