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Biomedical subjects

J Lipinski

Publications and source records attributed to J Lipinski.

At least 19 recordsLinked to original sources
PubMed2001

Automated solid phase dynamic extraction--extraction of organics using a wall coated syringe needle.

Extractions of liquid samples were carried out using wall coated needles prepared from stainless steel capillary columns instead of syringe needles. This micro extraction technique was applied to the analysis of pesticides in water. Important parameters influencing the extraction such as sample velocity, extraction time and also the desorption parameters were investigated and optimized. Automation of this technique was realized using a conventional automatic sampler. Limits of detection were improved using the multiple extraction/desorption technique. Chromatographic data and limits of detection were compared with those obtained by solid phase micro extraction (SPME). Using a needle with a 7 microns film yielded limits of detection varying from 0.001-0.1 microgram/L and were in the same range as those resulting from the extraction using a 100 microns polydimethylsiloxane (PDMS) SPME fiber. The main advantages of the needle extraction technique were the significantly higher extraction speed and the practical aspects of a stable steel needle compared to those of a fragile fiber. The extraction speed using a needle with a 7 microns film was up to five times higher than the speed of SPME using a 100 microns PDMS fiber. The steel needle could be stressed mechanically in a higher extent than a SPME fiber. Sample volumes and aliquots of liquid media could be handled and moved from one bottle to another using the automatic sampler.

Journal Article↗
PubMed2000

Automated multiple solid phase micro extraction. An approach to enhance the limit of detection for the determination of pesticides in water.

A method was developed to decrease the limit of detection (LOD) for pesticide residue analysis in water using multiple SPME. To enhance the absolute amount transferred to the GC column an enrichment step is integrated in the SPME/GC-analysis. A series of several extraction and desorption steps are performed and the analytes are trapped at the front of the cold GC column before the GC analysis is started. The parameters mainly influencing this enrichment are the equilibrium time, the slope of the adsorption time/peak area profile at its start, the number and the duration of the extraction steps. The role of these parameters was investigated.

Chromatography, Gas↗
PubMed1999

[High-dose Crataegus extract WS 1442 in the treatment of NYHA stage II heart failure].

The efficacy and tolerance of the standardized hawthorn (crataegus) extract WS 1442 were tested in a multicenter utilization observational study. We monitored 1,011 patients with cardiac insufficiency stage NYHA II, treated with this extract (Crataegutt novo 450, 1 tablet b.i.d.) over a period of 24 weeks. During and at the end of the observation period a significant improvement in clinical symptoms (reduced performance in the exercise tolerance test, fatigue, palpitation and exercise dyspnea) was observed. Ankle edema and nocturia disappeared by 83%, and by half of the patients respectively manifesting these symptoms before treatment. The improvement and economization of cardiac performance were additionally shown by a reduction in blood pressure, an increased maximal exercise tolerance and a reduction in the difference in the pressure/heart rate product (PHRP). The positive effects of WS 1442 were further demonstrated by an improved ejection fraction and an increased percentile shortening fraction measured using M-mode echocardiography. The stabilizing effect of the hawthorn extract on the heart rate was shown by a slower rest pulse, as well as by an increase in the number of day and night normorhythmic patients, as documented by long-term ECG. The reduction in the number of patients showing ST depressions, arrhythmias and ventricular extrasystoles at the maximum exercise level is regarded as an indication for an improved myocardial perfusion. Fourteen side effects were noted. In two cases (abdominal discomfort and facial pains accompanied by tachycardia) a possible relationship with the hawthorn therapy, was postulated which however was considered unlikely by the treating physicians. Almost 2/3 of the patients felt better or much better following the 24 weeks of treatment. More than 3/4 of the participating physicians noted a good or a very good efficacy, and 98.7% noted a good or a very good tolerance. High-dose hawthorn therapy is an efficient, well-tolerated and easily regulated therapeutic alternative for patients suffering from cardiac insufficiency stage NYHA II.

Dose-Response Relationship, Drug↗
PubMed1996

Amelanotic lentigo maligna melanoma: a diagnostic conundrum-- presentation of four new cases.

BACKGROUND: The clinical appearance of amelanotic lentigo maligna melanoma (ALMM) is quite confusing and usually is not diagnosed prior to histopathologic examination. METHODS: We have studied four new patients with ALMM whose correct diagnosis was not obtained from any one clinical finding. We arrived at the final diagnosis in an unexpected way, having had biopsied the lesions for diagnoses other than malignant melanoma. RESULTS: ALMM presents as a nonspecific skin lesion with no single indicative characteristic. A search of the literature confirmed our difficulty in making the diagnosis. CONCLUSIONS: To diagnose ALMM, one has to be cognizant of this condition and has to consider a constellation of findings that are unusual with melanocytic lesions. Questionable lesions must be biopsied for definitive histopathologic diagnosis.

Aged↗
PubMed1988

CAPA--Computer Aided Pesticide Analysis. Computer program for the automated evaluation of chromatographic data for residue analysis of foods.

Pesticide residue analysis in food by means of gas chromatography with columns of different polarity and several selective detectors provides the analyst with a great number of chromatographic data. The introduction of personal computer based chromatographic data systems into research laboratories increased the efficiency of information management and organization; user designed software packages now have direct access to the stored data. The computer program CAPA (Computer Aided Pesticide Analysis) was developed for the interpretation and evaluation of chromatographic results. The program is written in TURBO PASCAL 3.0 and consists of several subprograms. In the main database all pesticides are filed in a multidimensional structure. The various subprograms have access to this catalog of retention and response data. Using the subprogram INTERPRET, which is the core of CAPA, the analyst is provided with all information necessary to interpret a gas chromatogram: identification of calibrated pesticides and estimation of their concentration. Automated screening analyses can be evaluated with the subprogram AUTOINTERPRET, an automated of INTERPRET that uses all relevant information stored in the data base. A report is produced containing the pesticides found in the sample and proposals how to confirm them best with the equipment and methods available. Finally the analyst has to make the decision about the probable presence and quantity of the indicated pesticides and to project the next confirmatory step by using INTERPRET.

Autoanalysis↗
PubMed1985

Microcomputer programming in basic for the evaluation of capillary gas chromatography in the analysis of pesticide residues. I. MATRIXCOMP--a program that facilitates the recognition of interfering peaks from the biological matrix.

Chromatograms of pesticide residues in food include peaks produced by pesticides and matrix compounds. Pesticide peaks are recognized by means of relative retention times and response factors; two detectors are used and internal standard methods are applied. Chromatograms of reference samples for all types of food are stored as raw data in a reduced format, together with tables of all chromatographic data for the matrix compounds. MATRIXCOMP provides the analyst with the chromatograms of the actual sample and the reference in parallel on a visual display screen for visual comparison. Simultaneously, the relevant chromatographic data for the sample, the reference and the calibration tables are displayed on a second screen page in a condensed form.

Chromatography, Gas↗
PubMed1985

Differentiation of metastatic breast carcinoma from Stewart-Treves angiosarcoma. Use of anti-keratin and anti-desmosome monoclonal antibodies and factor VIII-related antibodies.

A chronic brawny edema developed in the shoulder and arm ipsilateral to the site of a previous mastectomy in a 68-year-old woman. Bluish nodules and telangiectasia admixed with more superficial papules and plaques developed subsequently. Histologically, many of these lesions showed angiocentric clusters of large hyperchromatic tumor cells, often with lumina in the center. It was difficult to differentiate two possibilities, ie, postmastectomy angiosarcoma in lymphedema (Stewart-Treves syndrome) and nodulotelangiectatic metastasis of the original breast carcinoma. Monoclonal anti-keratin antibody and anti-desmosome antibody identified keratin and desmosomes in the tumor cells, whereas staining with factor VIII-related antigen yielded negative results. Electron microscopy revealed, in addition to keratin filaments and desmosomes, typical secretory cells and lumen formation. A combined use of specific monoclonal and polyclonal antibodies is helpful in the determination of tumor origins.

Aged↗