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PubMedDate not supplied

Determination of organochlorine pesticides in cheese.

A multiresidue technique was developed for the analysis of 17 organochlorine compounds in cheese: alpha-hexachlorocyclohexane (alpha-HCH), beta-HCH, gamma-HCH, delta-HCH, aldrin, dieldrin, endrin, heptachlor, heptachlor epoxide, chlordane, o,p'- ... (o,p'-DDT), p,p'-DDT, o,p'- ... (o,p'-DDD), p,p'-DDD, o,p'- ... (o,p'-DDE), p,p'-DDE, and the fungicide hexachlorobenzene. In this technique, the fat, previously extracted from the cheeses, was subjected to 2 cleanup and extraction methods: with H2SO4, for acid-resistant organochlorine pesticides, and with KOH-ethanol. The behavior of the compounds in both treatments enabled us to identify the organochlorine pesticides in cheese. The precision (repeatability and reproducibility) and accuracy of the technique were validated.

Animals↗

PubMed1995

Carbon-11-cocaine binding compared at subpharmacological and pharmacological doses: a PET study.

UNLABELLED: We have characterized cocaine binding in the brain to a high-affinity site on the dopamine transporter using PET and tracer doses of [11C]cocaine in the baboon in vivo. The binding pattern, however, of cocaine at tracer (subpharmacological) doses may differ from that observed when the drug is taken in behaviorally active doses particularly since in vitro studies have shown that cocaine also binds to low affinity binding sites. METHODS: PET was used to compare and characterize [11C]cocaine binding in the baboon brain at low subpharmacological (18 micrograms average dose) and at pharmacological (8000 micrograms) doses. Serial studies on the same day in the same baboon were used to assess the reproducibility of repeated measures and to assess the effects of drugs which inhibit the dopamine, norepinephrine and serotonin transporters. Time-activity curves from brain and the arterial plasma input function were used to calculate the steady-state distribution volume (DV). RESULTS: At subpharmacological doses, [11C]cocaine had a higher binding and slower clearance in striatum than in other brain regions. At pharmacological doses, [11C]cocaine had a more homogeneous distribution. Bmax/Kd for sub-pharmacological [11C]cocaine corresponded to 0.5-0.6 and for pharmacological [11C]cocaine it corresponded to 0.1-0.2. Two-point Scatchard analysis gave Bmax = 2300 pmole/g and Kd' = 3600 nM. Bmax/Kd for sub-pharmacological doses of [11C]cocaine was decreased by cocaine and drugs that inhibit the dopamine transporter, to 0.1-0.2, but not by drugs that inhibit the serotonin or the norepinephrine transporter. None of these drugs changed Bmax/Kd for a pharmacological dose of [11C]cocaine. CONCLUSION: At subpharmacological doses, [11C]cocaine binds predominantly to a high-affinity site on the dopamine transporter.

Animals↗

PubMed1994

A new method to assess gastric mucosa rewarming time in patients with portal hypertension.

It is possible that the mucosal damage in congestive gastropathy of portal hypertensive patients may have an ischemic basis, since rewarming time in other sites correlates with local blood flow, a method was designed to assess the capacity of the gastric mucosa to rewarm the stomach after a cold challenge, as an index of ischemia. Eleven control subjects and 15 patients with portal hypertension (10 treated with sclerotherapy) were studied with an integrated circuit temperature transducer connected to a digital display. A balloon containing the temperature transducer inside was reversibly fixed 10 cm. proximally to the distal end of a panendoscope. Once upper endoscopy was completed, the balloon placed in the antrum was infused with cooled water (2 degrees C) through a polyethylene tube. The time elapsed for the water to be rewarmed from 20 degrees C to 25 degrees C to 30 degrees C and 20 degrees C to 30 degrees C was measured. Reproducibility of repeated measurements, gave a coefficient of variation of 6%. Total rewarming time was (-mean +/- SD) 178 +/- 51.3 seconds, significantly higher in Portal hypertensive patients as compared to 114 +/- 34.7 seconds in Controls (P < 0.001). (95% Confidence Interval: -X = 63.4 seconds Cl 45.02 to 81.78). 60% of Sensitivity and 100% of Specificity The slower rewarming time in patients with portal hypertension may be the result of mucosal ischaemia, but oedema and cellular infiltration could also affect the heat flow.

Adolescent↗

PubMed1994

[Treatment of writer's cramp with botulinum toxin].

Writer's cramp is a focal dystonia that is resistant to most treatment regimens. This article describes two patients with writer's cramp who were successfully treated with botulinum toxin injections into the forearm muscles. Transient weakness due to the effect of botulinum toxin was registered in the injected muscles. No other side effects were observed. The beneficial effect of a single injection lasted from three to four months and could be reproduced by repeated injections over a three year follow-up period. We conclude that botulinum toxin injections may provide safe and effective treatment in selected patients with writer's cramp.

Botulinum Toxins↗

PubMed1975

[Comparative study of four national disinfectant testing techniques (author's transl)].

Four methods for the evaluation of the bactericidal property of disinfectants have been compared. These methods are (1) the qualitative suspension test of the directives for the testing of disinfectants of the German Society for Hygiene and Microbiology, (2) the quantitative suspension test of the dutch committee on phytopharmacy, (3) the carrier or use-dilution method of the A.O.A.C. and (4) the KELSEY and SYKES' capacity test. Aim of this study has been the evaluation of (1) the repeatability and reproducibility of the test results of the four methods, and of (2) the agreement of the degree of efficiency as determined by the different techniques. At least three dilutions of the three disinfectant standards (a phenolic, an aldehyde solution and an iodophore) have been tested against Staphylococcus aureus and Pseudomonas aeruginoas. In this article the authors describe the methods used and the specific difficulties of these techniques. In the suspension technique of the DGHM, the use of only one subculture is stated as not sufficient for exact evaluation of the extinction. In the dutch suspension test, the use of pour plates leads to troubles. The preparative incubation time of the use-dilution method of the A.O.A.C. has been experienced as too long. The structure of the KELSEY and SYKES' test is complicated. Also the results by the two research-teams, are reported and summarized. It has been found that the transition from active to inactive dilution is most marked in the two suspension tests, whereas the distinction between the results of the use-dilution method of the A.O.A.C. is not so clear.

Aldehydes↗

PubMed1993

Use of colostrum to detect antibodies against glycoprotein I of Aujeszky's disease virus.

Serum and colostrum samples taken from 499 sows from five herds of pigs endemically infected and vaccinated against Aujeszky's disease virus, were used to investigate whether colostrum could be used to detect antibodies against glycoprotein I (gI) of the virus. Using serum as the reference, the test applied to colostrum had a sensitivity of 97 per cent and a specificity of 88 per cent. When samples were taken from 50 sows from a gI seronegative vaccinated herd, one colostrum sample was gI-positive, giving a specificity for the test of 98 per cent. The mean gI antibody titres in colostrum were about six times higher than in serum. Samples of colostrum were also taken from 132 sows from eight unvaccinated herds free of Aujeszky's disease virus. All these samples were gI-negative, giving a specificity of 100 per cent. Colostrum samples can be stored for at least six weeks at -20 degrees C without compromising the test results, and the repeatability and reproducibility of the test applied to colostrum were good.

Animals↗

PubMed1994

Peroxynitrite, a product of superoxide and nitric oxide, produces coronary vasorelaxation in dogs.

The vascular effect of peroxynitrite (ONOO-), a product of superoxide anion and nitric oxide, in isolated canine coronary arteries bathed in a 10 mM 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid-buffered physiological salt solution (pH 7.4) was investigated. ONOO- was synthesized from nitrite and H2O2 in a quenched-flow reactor. Addition of 0.01 to 30 microM ONOO- produced a rapid, dose-dependent relaxation in all 17 rings of coronary arteries with a threshold concentration of 0.1 microM, IC50 of 1.0 +/- 0.1 microM and Emax of -96 +/- 0.5% (Means +/- S.E.M.). Incubation of arteries in a standard bicarbonate-buffered Krebs-Henseleit solution decreased slightly the sensitivity of ONOO- relaxation but did not alter the maximum effect (Emax = -97 +/- 1.1, n = 6 vessels). The ONOO(-)-induced coronary relaxation was reversible upon washing, and was also reproducible with repeated testings in the same ring. Mechanical removal of intimal endothelium did not alter the observed relaxant effect. Addition of superoxide dismutase (100 U/ml) potentiated the ONOO- relaxation by shifting the dose-response curve to the left (IC50 = 0.4 +/- 0.1 microM, P < .05, n = 17), whereas 3 microM hemoglobin inhibited it by shifting the curve to the right (IC50 = 20 +/- 4 microM, P < .05, n = 15). Relaxation was also observed with higher concentrations of sodium nitrite and decomposed ONOO-, although the time course of the development of these relaxations was considerably slower and with reduced sensitivity. In addition, superoxide dismutase had no effect on the latter relaxation responses.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

Fine needle tissue aspiration biopsy of the testis.

OBJECTIVE: To develop a fine needle tissue aspiration biopsy technique that provides sufficient tissue for accurate histological assessment and research purposes. DESIGN: After assessing different needles and developing a method for handling small amounts of tissue, 87 patients underwent fine needle tissue aspiration biopsy. The quantity, quality, and appearance of the tissue was examined and adverse effects of the procedure were noted. Fine needle tissue aspiration and open biopsy samples were compared in 26 patients. Suitability of the tissue for flow cytometry and electron microscopy was also assessed. RESULTS: The 20-gauge, 5-cm Menghini and Turner biopsy needles penetrated the testis more readily and recovered larger quantities of tissue. Adequate samples were recovered from 83% of cases (average of 21.8 tubule sections per testis) with the frequency of recovery and the amount of tissue obtained increasing through-out the study. Some distortions of the tissue were seen but these rarely interfered with the diagnosis. Although many patients suffered slight discomfort during the injection of the anesthetic, no serious complications were encountered during or after the procedure. Comparison of fine needle tissue aspiration and open biopsy diagnoses found either full agreement (56%) or slight differences (38%) in the degree of hypospermatogenesis. CONCLUSIONS: Fine needle tissue aspiration biopsy was found to be a quick, easy, repeatable, and reproducible method of obtaining testicular tissue. No serious adverse effects of the procedure were detected and the diagnoses were found to be comparable to those obtained by open biopsy.

Adult↗

PubMedDate not supplied

Liquid chromatographic method for determination of sulfamethazine residues in milk: collaborative study.

Seven laboratories participated in a collaborative study of a liquid chromatographic (LC) method for determination of sulfamethazine (SMZ) residues in raw milk that were previously frozen. The milk is extracted with chloroform, the chloroform is evaporated, and the residue is suspended in hexane and extracted with 0.1M KH2PO4 (PDP) solution. The PDP extract is analyzed by LC on a C18 column with methanol-0. 1M PDP (30 + 70) as mobile phase. Individual laboratories were instructed to analyze 5 replicates each of control milk, fortified control milk at 2 levels, and 3 blind samples. Blind samples included raw milk fortified with SMZ at 10 and 20 ppb and 1 sample containing SMZ residue from a dosed cow. For blind fortified samples containing 10 ppb SMZ, average recovery and relative standard deviations for repeatability and reproducibility (RSDr and RSRR) based on the results from 6 of the 7 participating laboratories were 8.21 ppb, 7.16%, and 23.16%, respectively. Similar data, including results from a seventh participant who reported instrumental problems but was not eliminated by the Dixon outlier test, were 9.13 ppb, 8.38%, and 31.94%, respectively. These results demonstrate that the method is suitable for the determination of SMZ residues in milk at 10 ppb and above. The method was adopted first action by AOAC International.

Animals↗

PubMedDate not supplied

Liquid chromatographic method for determination of diquat and paraquat herbicides in potatoes: collaborative study.

A liquid chromatographic (LC) method for the determination of diquat and paraquat herbicides/desiccants in potatoes was collaboratively studied in 6 laboratories. Analytes are extracted from 5 g sample with dilute acid by using a microreflux procedure; the hydrolysate is adjusted to pH 9-10 and passed through a disposable silica cartridge for rapid cleanup and preconcentration. Analytes are separated on a reversed-phase LC column and are measured as their heptanesulfonate ion pairs by UV detection. Each collaborator determined diquat and paraquat at 4 levels (0.05, 0.1, 0.5, and 1.0 ppm) in blind duplicate samples plus 2 blind negative control samples. Potatoes, obtained from each participant's region, were spiked by the collaborators with unknown aqueous solutions containing no analyte or a mixture of diquat and paraquat standards. Repeatability and reproducibility relative standard deviations (RSDr and RSDR) averaged 17.1 and 29.0%, respectively, for determination of diquat and 10.8 and 29.5%, respectively, for paraquat. For analysis of standard solutions, RSDr and RSDR values were 6.3 and 12.0%, respectively, for diquat and 7.3 and 13.9%, respectively, for paraquat. Accuracy, measured by comparison with true spiking values (absolute recovery) averaged 77.6 and 76.2% for diquat and paraquat, respectively, and ranged from 71.8 to 88.0% for both compounds. The method was adopted first action by AOAC International.

Chromatography, Liquid↗

PubMedDate not supplied

Enzymatic-gravimetric determination in foods of dietary fiber as sum of insoluble and soluble fiber fractions: summary of collaborative study.

A collaborative study was conducted on an enzymatic-gravimetric method for determination of total dietary fiber in foods, in which soluble fiber and insoluble fiber are determined separately. Ten collaborators analyzed blind duplicate test samples from 5 food products: turnip, wheat bran, beans canned with tomato sauce, rice, and whole wheat bread. Repeatability and reproducibility relative standard deviations ranged from 1.48 to 14.73% and from 4.13 to 17.94%, respectively. The method was adopted first action by AOAC International.

Bread↗

PubMed1995

[Functional laryngeal obstruction].

We describe 4 patients with reversible obstruction of the upper airways, a condition that usually presents with crises of dyspnea and respiratory sounds. No organic cause could be identified and the symptoms were initially confused with those of bronchial asthma. During episodes, the flow-volume curve suggested obstruction of the upper airways with poor reproducibility and repeatedly normal resistance values. Fiberoptic bronchoscopy allowed us to confirm the functional nature of the obstruction in these cases.

Adult↗

PubMedDate not supplied

Determination of D-malic acid in apple juice by liquid chromatography: collaborative study.

Eleven laboratories collaboratively studied a liquid chromatographic (LC) method for determination of D-malic acid in apple juice. The mobile phase consisted of mM L-valine and 8 mM copper acetate adjusted to pH 5.5 with NaOH. The UV detector was set at 330 nm, and a single reversed-phase LC column was used. Seven paired samples containing various amounts of D-malic acid ranging from 0 to 188 mg/100 mL of 12 Brix pasteurized apple juice were tested by each collaborator. Repeatability and reproducibility coefficients of variation ranged from 1.0 to 3.5% and 7.7 to 11.7%, respectively, within the range of 26 to 188 mg D-malic acid/100 mL of 12 Brix apple juice. The collaborative study results demonstrated that the method could quantitate the economic adulteration of apple juice with DL-malic acid at lower levels than those reported with previous methods. The LC method for determination of D-malic acid in apple juice has been adopted first action by AOAC INTERNATIONAL.

Beverages↗

PubMed1995

[Evaluation of coronary risk: a new technique of measuring lipoprotein (a)].

The aim of this study was to assess the reliability of immuno-nephelemetric assay (INA) of lipoprotein (Lp(a)) compared with immuno-radiometric (IRMA) and immuno-enzymologic (ELISA) assays in a coronary (P1) and a non-coronary (P2) populations. The serums of 66 coronary subjects (P1) with an average age of 61.5 +/- 10 years and 137 non-coronary subjects (P2) with an average age of 54 +/- 12 years were analysed by the 3 techniques. The technical characteristics of the INA were: negligeable interference with plasminogen (PLG) (< 1/100) for PLG < 375 mg/l; excellent repeatability and reproducibility at low, medium and high concentrations, respectively 12.3 and 7.5%. 1.2 and 1.2%, 1.3 and 1.1%, low dependance on sample conservation (stable 5 days at +4 degrees C), excellent practicability (simple and quick automised analysis: 10 min). The linear correlations with the concentrations of Lp(a) were: excellent with INA/IRMA P1 and P2: 0.99; very good with INA/ELISA P1: 0.88 and P2: 0.85; very good between IRMA/ELISA P1: 0.91 and P2: 0.87. The average values of Lp(a) were 386 mg/l (INA), 339 mg/l (IRMA), 316 mg/l (ELISA) for P1, and 231 mg/l (INA), 212 mg/l (IRMA) and 153 mg/l (ELISA) for P2, with a significant difference between P1 and P2 with all three techniques: 0.0138 (INA), 0.0207 (IRMA) and 0.0001 (ELISA). The authors concluded that measuring Lp(a) by INA is reliable with respect to IRMA and ELISA techniques, as accurate, quicker, automatised and cheaper, compensating for a lower sensitivity, a calculated risk of a non-specific reaction and the necessity of a shorter delay of analysis. The comparative results in two populations demonstrate it to be an excellent marker of coronary risk for epidemiological studies, independant of other risk factors.

Adult↗

PubMedDate not supplied

[The consolidation and reproduction of a state of haloperidol-induced catalepsy].

Catalepsy induced by a single intraperitoneal injection of haloperidol (2.5 mg/kg) was consolidated and without additional influences and retained within 2 week (being tested on the 2nd, 7th, and 14th days after injection). Enhancement of catalepsy retrieval was observed during testing of the same animals on the 14th day as compared with the 7th day. Maximal catalepsy expression was reached after 2 hours of testing procedure which points to the existence of the mechanism of autoenhancement of retrieval which is probably underlain by the automodulation of the long-lasting modulatory DA receptors. The retrieval of catalepsy is suggested to be induced by a situational conditioned stimulus, since on the 2nd, 7th and 14th days it may be reproduced without repeated haloperidol injection only in the testing box.

Animals↗

PubMedDate not supplied

Two-day hydrophobic grid membrane filter method for yeast and mold enumeration in foods using YM-11 agar: collaborative study.

Twenty laboratories participated in a collaborative study to validate a 2-day hydrophobic grid membrane filter method using YM-11 agar for enumeration of yeast and mold in foods. Six naturally contaminated food products were included in the study: garlic powder, raw ground beef, walnuts, flour/meal, orange juice, and yogurt. The test method produced significantly higher results than the 5-day pour plate reference method for orange juice and significantly lower, though numerically similar, results for walnuts and yogurt. Differences between the test and reference methods were not significant for garlic powder, raw ground beef, or flour/meal. Repeatability and reproducibility were similar for both the test and reference methods in all cases. The hydrophobic grid membrane filter method for enumeration of yeast and mold in foods has been adopted by AOAC INTERNATIONAL.

Agar↗

PubMed1996

[Immunoenzymatic assays of c-erbB-2 oncoprotein and epidermal growth factor receptor in breast cancer: correlation with clinical and biological parameters].

Two new immunoenzymatic assays for c-erbB-2 oncoprotein and epidermal growth factor receptor (EGF-R) (Oncogene Science) in human breast cancer were validated. Correlations between these assays and some clinical and biological parameters were also studied. The repeatability and reproducibility of standard curves for the two methods gave a coefficient of variation (CV) of less than 4% and about 10% respectively. The accuracy of c-erbB-2 oncoprotein and EGF-R assays was examined by using dilution and recovery tests throughout the standard curves. The linear relations between theoretical and measured values, for these tests, had slopes close to 1 and an intercept near 0. The median value for EGF-R, measured on solubilized membranes of 290 primary tumors, was 0.12 fmol/micrograms protein, the mean value was 0.37 (range 0 to 35.7). For c-erbB-2 oncoprotein, the median value, measured using the same population, was 2.75 human neu unit/micrograms protein, the mean value was 7.85 (range 1 to 125). There was an inverse relationship between EGF-R values and those for the estrogen receptor (ER), progesterone receptor and pS2 protein as well as menopausal status. C-erbB-2 oncoprotein concentrations were positively correlated with ER, pS2 protein and cathepsin D. Furthermore, a significant positive correlation was observed between EGF-R levels and c-erbB-2 oncoprotein levels. In conclusion, immunoenzymatic assays of EGF-R and c-erbB-2 oncoprotein are easy to use, sensitive and reliable. The accurate standardisation of immunoenzymatic assays could contribute to the clinical use of EGF-R and c-erbB-2 oncoprotein as prognostic factors in breast cancer.

Breast Neoplasms↗

PubMedDate not supplied

Determination of atrazine in water by magnetic particle immunoassay: collaborative study.

A collaborative study was performed to determine mean recovery and precision for analysis of atrazine in drinking and surface waters by immunoassay. The study design was based on the blind duplicate test plan for collaborative studies. Three blank waters (municipal drinking water, well water, and surface water) were spiked at 3 atrazine levels. Two water samples with naturally incurred atrazine loads were also spiked with atrazine at 3 levels. In the enzyme-linked immunoassay method, the water sample is mixed with a pesticide-enzyme conjugate and added to paramagnetic particles with triazine-specific antibodies attached. After separation of antibody-bound atrazine and atrazine-enzyme conjugate from free components, the bound enzyme conjugate catalyzes a reaction producing a colored end product. The color developed is inversely proportional to the original concentration of atrazine in the water sample. Fourteen laboratories participated in the collaborative study. Data were analyzed for repeatability and reproducibility, and average recoveries at the spike levels were calculated. Over the concentration range tested, the mean recovery of atrazine spiked into blank and pesticide-contaminated waters was 104%. Overall RSDR averaged about 40% for atrazine concentrations near the method detection limit (0.05 microgram/L) and about 15% at concentrations above 5 times the detection limit (0.25 microgram/L). Corresponding single-analyst RSDr values were 24 and 10%. Recovery and precision for the 3 blank water matrixes and the waters that had been naturally contaminated with atrazine showed no significant differences. The magnetic particle immunoassay for determination of atrazine in water has been adopted first action by AOAC INTERNATIONAL.

Atrazine↗