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PubMed1981

[Performance and limitations of the analysis of HDL-cholesterol (author's transl)].

Comparing published data, three methods for HDL-cholesterol determination (phosphotungstate/MgCl2, dextran sulphate 500/MgCl2 and heparin/MnCl2) are reviewed with respect to accuracy, precision, sensitivity and liability to interference. All three methods are specific (complete precipitation of apolipoprotein B-containing lipoprotein) and sufficiently sensitive (only significant coprecipitation of HDL). A disadvantage of the heparin/MnCl2 method is incomplete precipitation of apolipoprotein B-containing lipoprotein in hypertriglyceridemic sera. Limitations of the diagnostic value of HDL-cholesterol analysis are discussed.

Apolipoproteins↗
PubMed1981

Separation of serum high-density lipoprotein for cholesterol determination: ultracentrifugation vs precipitation with sodium phosphotungstate and magnesium chloride.

We compared two methods for separation of serum high-density lipoprotein: selective precipitation with sodium phosphotungstate and magnesium chloride, and ultracentrifugation in sodium chloride solution (relative density 1.063). When the cholesterol content (determined enzymically with a centrifugal analyzer) of fractions obtained by each method was compared (ultracentrifugation = x), the correlation coefficient was 0.97; y = 1.01x - 11.2 mg/L; p less than 0.05; n = 54. The within-day and between-day coefficients of variation for this method were 1.1 and 4.0%, respectively. Reference intervals for high-density lipoprotein cholesterol in subpopulations categorized by age and sex were based on data obtained from volunteer blood donors.

Chemical Precipitation↗
PubMed1980

Applicability of various quality-control sera to assay of high-density lipoprotein cholesterol.

Effective internal quality control and external quality assessment of high-density lipoprotein cholesterol assay is made difficult by analyte instability, and the suitability of quality-control sera for this purpose has not been studied. We have therefore investigated the properties of 25 different control sera from 15 suppliers by estimating within-batch precision for the two precipitation procedures used most widely (phosphotungstate/Mg2+ and heparin/Mn2+ with enzymic measurement of cholesterol. Some sera had properties similar to those of fresh human serum, but others demonstrated poor precision for one or both procedures or contained apparent high-density lipoprotein cholesterol in unphysiological concentrations. A study of six sera indicated that between-batch precision was consistent with the within-batch findings. We found that eight of the 25 batches of quality-control serum we investigated may be used for internal quality control and external quality assessment of high-density lipoprotein cholesterol assay.

Chemical Precipitation↗
PubMed1980

Heparin--magnesium chloride--albumin method for enzymic measurement of cholesterol in high-density lipoprotein.

We describe a new method for measuring high-density-lipoprotein cholesterol in sera, with use of heparin, MgCl2, and albumin to precipitate very-low- and low-density lipoproteins, Lipoprotein electrophoresis and immunochemical methods show that high-density lipoprotein is completely and specifically isolated in the supernate, the cholesterol concentration of which is estimated by the enzymic method of Allain et al. (Clin. Chem. 20, 470, 1974). The precision of the method is excellent (CV = 1%) and the response is linear. Values so obtained correlate well with those obtained with the heparin-Mn2+ (r = 0.98) or the phosphotungstate-Mg2+ (r = 0.98) procedures. The technique is appropriate for routine clinical laboratory use.

Adult↗
PubMedDate not supplied

Bronchioloalveolar carcinoma in progressive systemic sclerosis. Report of a case diagnosed by fine needle aspiration cytology.

BACKGROUND: Progressive systemic sclerosis (PSS) is a systemic disorder involving many internal organs, including the lungs. The occurrence of a pulmonary tumor has occasionally been reported, especially in long-standing cases. Bronchioloalveolar carcinoma is the most prevalent histologic type. CASE: A 35-year-old male with a 12-year history of PSS presented with exertional dyspnea and pain in the left side of the chest. Fine needle aspiration cytology (FNAC) showed abundant cellular material with large, monolayered sheets and papillary structures. The neoplastic cells had uniform round to oval nuclei and spacious cytoplasm. Some had intranuclear vacuoles. Phosphotungstic acid-hematoxylin (PTAH) stain revealed structures in the form of prominent cell membranes rimming the free surfaces of the tumor cells. The overall cytologic picture was interpreted as consistent with bronchioloalveolar carcinoma. The patient's condition did not permit surgery. CONCLUSION: In this case the development of bronchioloalveolar carcinoma occurred over a 12-year period following the diagnosis of PSS. This case emphasizes diagnosis of the tumor solely by FNAC. PTAH stain was also helpful in the cytologic diagnosis.

Adenocarcinoma, Bronchiolo-Alveolar↗
PubMed1994

Nonlinearity of high-density lipoprotein cholesterol determinations is matrix dependent.

The majority of methods for determining high-density lipoprotein (HDL) cholesterol failed the 1991 College of American Pathologists (CAP) linearity survey (sets LN2-A, B, C). We hypothesized that they failed because of the survey material matrix. We evaluated linearity with dextran sulfate or phosphotungstate as the precipitating reagents for several methods: Ektachem; TDx; Sigma; Dimension; Cobas Fara, with Roche reagents; and the Hitachi 736, with precipitating reagents from Boehringer Mannheim Diagnostics. We tested CAP survey material, Sigma HDL-cholesterol control material, and a fresh serum pool for linearity, using the polynomial method. All of the methods were nonlinear for the CAP material and for the controls precipitated after dilution. Five of eight methods were linear for the control materials precipitated before dilution. All methods but one were linear for the serum pool. These results demonstrate that the source of the nonlinearity is located in the precipitation step and depends on the sample matrix.

Chemical Precipitation↗
PubMed1994

Oncocytic mucoepidermoid carcinoma of the parotid gland.

Oncocytic mucoepidermoid carcinoma of the salivary gland is rare. We describe a 60-year-old woman who presented with a slowly growing left parotid mass. The patient underwent a total parotidectomy, and her postoperative course was uneventful. The gland was enlarged and showed a partially cystic mass containing clear mucoid material. Microscopically, the entire mass showed variably sized cysts lined predominantly with oncocytes and a few mucous goblet cells. Histochemical stains for mitochondria, such as phosphotungstic acid-hematoxylin, confirmed the presence of oncocytes. The recognition of this variant is important, since most of the other primary oncocytic lesions of the salivary glands are benign. The tumor in this case is considered to be a low-grade carcinoma; therefore, complete surgical excision and long-term clinical follow-up are adequate management.

Carcinoma, Mucoepidermoid↗
PubMed1993

Ultrastructural evidences of a distinct axial domain within native rat tail tendon collagen fibrils.

The structure of collagen fibrils of tail tendon in young and mature rats was investigated by transmission (TEM) electron microscopy after cytochemical methods associated with special procedures of dehydration and fixation. All the collagen fibrils show a central condensed material of 4 nm in diameter which remains preserved even when fibrils have been swollen and partly disorganized by the ethyl glycol dehydration. A cytochemical characterization using PTA and TCH treatments strongly suggests the glycoprotein nature of this central compact material and reveals the heterogeneous structure of each fibril. The first morphological evidence that the construction of the collagen fibrils must take place around a condensed material which serves as a scaffolding is obtained. These observations are in agreement with the now well established existence of heterotypic collagen fibrils in many extracellular matrices.

Age Factors↗
PubMed1993

A multi-centre evaluation of the measurement of high density lipoprotein cholesterol by the Reflotron assay.

A multi-centre study was undertaken to evaluate the performance of the Reflotron high density lipoprotein cholesterol method in twelve different clinical chemistry hospital laboratories. Results were compared with phosphotungistic acid/Mg2+ and polyethylene glycol/dextran sulphate/Mg2+ precipitation methods, routinely performed in these laboratories. Precision was found to be excellent, for both the day-to-day results (SD = 0.03 mmol/l) and for the overall between-laboratory precision (SD = 0.02 mmol/l), measured with control sera. HDL cholesterol concentrations measured with the Reflotron system were about 10% lower than those obtained with the two routine precipitation methods, using different instruments with different cholesterol standardization procedures.

Chemistry, Clinical↗