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Biomedical subjects

P Albrecht

Publications and source records attributed to P Albrecht.

At least 19 recordsLinked to original sources
PubMed2003

Gemcitabine and carboplatin in patients with locally advanced or metastatic non-small cell lung cancer: a prospective phase II study.

PURPOSE: The primary objective of this phase II study was to determine the tumor remission rates in previously untreated patients with advanced or metastatic non-small cell lung cancer (stage IIIB and IV), after treatment with gemcitabine plus carboplatin. Secondary objectives of this study were to determine toxicity, median survival and progression free survival in the same patient population treated with gemcitabine plus carboplatin. PATIENTS AND METHODS: Chemonaive patients with histological or cytological diagnosis of stage IIIB or IV NSCLC and Karnofsky performance status >/=60 received gemcitabine 1000 mg/m(2) over 30 min on days 1 and 8 and carboplatin AUC 5.0 over 30 min on day 1 after the gemcitabine infusion. Treatment cycles were repeated every 21 days for a maximum of six cycles, or until disease progression or unacceptable toxicity occurred. RESULTS: Of the 60 patients qualified for efficacy analysis, five achieved complete remissions, 15 partial remissions and 33 had stable disease, for an overall objective response rate (CR+PR) of 33.3% (95% CI, 21.7-46.7%). Four patients had progressive disease. The predominant toxicity was hematologic, with grade 3/4 leucopoenia being most common (35% patients). The median duration of response was 5 months, median time to progression was 6 months and median survival was 9 months with 80% of patients censored. CONCLUSION: Gemcitabine plus carboplatin is an effective and well tolerated treatment for advanced NSCLC.

Adenocarcinoma↗
PubMed2001

Extensive and partial protein hydrolysate preterm formulas: the effect on growth rate, protein metabolism indices, and plasma amino acid concentrations.

BACKGROUND: The use of protein hydrolysate preterm formulas is restricted because data on their nutritional adequacy are scarce. The authors evaluated the rate of growth and indices of protein metabolism in low-birth weight infants fed extensive and partial protein hydrolysate preterm formula followed for 12 weeks. METHODS: A total of 61 low-birth weight infants were assigned randomly to receive extensive protein hydrolysate preterm formula (EH: n = 16), partial protein hydrolysate preterm formula (PH: n = 15), and standard preterm formula (SF; n = 15), or were fed their own mother's fortified breast milk (FBM; n = 15). The infants were investigated at study entry, and at 4, 8, and 12 weeks after study entry. RESULTS: There were no differences with respect to growth rate (weight gain, increments in length and head circumference), urea, albumin, prealbumin, transferrin, and plasma amino acid concentrations (except for tyrosine on a single occasion) according to the degree of hydrolysis. There were also no differences between groups fed hydrolyzed formulas and SF. However, several differences were found when EH and PH were compared with FBM. Weight gain from the entry to 12 weeks, serum urea at 12 weeks, and total plasma essential amino acids at 8 weeks were significantly higher in groups fed EH and PH than in those fed FBM. In addition, valine was significantly higher in groups fed PH (P < 0.05) than in the group fed FBM at 8 and 12 weeks, tyrosine was higher in EH and PH in comparison with FBM at 4 weeks, and in PH versus FBM at 12 weeks after study entry. CONCLUSIONS: This study suggests that experimental EH and PH are at least nutritionally equivalent to SFs.

Amino Acids↗
PubMed2000

7,11-cyclobotryococca-5,12,26-triene, a novel botryococcene-related hydrocarbon occurring in natural environments

[formula: see text] With the unambiguous structural characterization of 7,11-cyclobotryococca-5,12,26-triene 1 by NMR, a novel C30 botryococcene-related hydrocarbon skeleton bearing a midchain five-membered ring has been identified in organic-rich sediments from Lake Cadagno (Switzerland). This compound may originate from the green alga Botryococcus braunii (race B) widespread in recent and past environments. Alternatively, it may also be a yet unreported lipid of green sulfur photosynthetic bacteria (Chlorobiaceae) or a microbial transformation product of the farnesol produced by the latter.

Journal Article↗
PubMed2000

Occurrence of precursors of regular tricyclopolyprenoids in recent sediments

[structure: see text] Two novel C24 tricyclic alkenes of the cheilanthane series have been isolated from the solvent extract of a sulfur-rich recent sediment and their structures determined by NMR studies. They represent the first example of functionalized tricyclic hydrocarbons structurally related to the tricyclopolyprenanes widespread in ancient sediments and petroleum identified in recent sediments.

Journal Article↗
PubMed2000

Glycosides and phenylpropanoid glycerol in vitis vinifera cv. Gewurztraminer wine.

Eight glycosides and a phenylpropanoid glycerol were isolated from Vitis vinifera cv. Gewurztraminer wine, and their structures were elucidated by MS and NMR spectroscopies. cis-1-(5-Ethenyl-5-methyltetrahydrofuran-2-yl)-1-methylethyl O-beta-D-apiofuranosyl-(1-->6)-O-beta-D-glucopyranoside, (E)-3,6, 9-trihydroxymegastigm-7-ene 9-O-beta-D-glucopyranoside, 2-phenylethyl O-beta-D-apiofuranosyl-(1-->6)-O-beta-D-glucopyranoside, and 2-[4-(3-hydroxypropyl)-2-methoxyphenoxy]propane-1,3-diol are reported for the first time as wine components.

Glycerol↗
PubMed2000

[Intracutaneous tuberculin test using the Mendel-Mantoux technique. Tuberculin reactivity among inpatients in a pneumology department].

Detection of latent tuberculosis infection is an important step in the control of tuberculosis. The tuberculin skin test is the only proven method for identifying tuberculosis infection in patients who do not have tuberculosis disease. The prevalence of tuberculosis infection among hospitalized patients in a pneumological department of an inner-city hospital was evaluated, using the intradermal tuberculin skin test (Mantoux technique). Interpretation of the Mantoux test was based on the size of induration in millimeters and the individual risk profile of the patients, according to the guidelines of the American Thoracic Society and the Centers for Disease Control, revised in 1989. Of 697 tested patients, 252 showed test results consistent with tuberculosis infection (36.2%). 55 of these 697 patients had active tuberculosis disease or a prior history of tuberculosis (7.9%). A positive tuberculin skin test was found in 197 of 642 patients (30.7%) with a diagnosis different from tuberculosis (COPD, pneumonia, cancer and others). In our study, the sensitivity of the tuberculin skin test for active tuberculosis infection was 95%. The present study revealed a high prevalence of tuberculosis infection among hospitalized patients in a pneumological department. Further studies are needed to assess the usefulness of routine tuberculin skin testing in hospitalized populations.

Adult↗
PubMed1998

The use of 13C-labelled polycyclic aromatic hydrocarbons for the analysis of their transformation in soil.

The formation of non-extractable residues during biodegradation and humification processes in soils and sediments represents a major sink for organic contaminants. The mode of incorporation of polycyclic aromatic hydrocarbons (PAH) and their metabolites into macromolecular organic matter during microbial degradation was studied applying 13C-labelled compounds. Mineralisation rates were determined by measuring the 13CO2 production. An incorporation of 13C-PAH-fragments into humic material could be traced by isotopic analysis of the bulk organic matter. Furthermore, selective chemical degradation reactions were performed to analyse the precise chemical structure of covalently bound 13C-labelled PAH fragments in soil humic substances. Structural assignments by GC-MS combined with isotope measurements on the bulk organic carbon and at the molecular level (Isotope Ratio Monitoring-GC-MS) provided useful information on the fate of xenobiotics within the soil.

Anthracenes↗
PubMed1997

Electrical alternans during rest and exercise as predictors of vulnerability to ventricular arrhythmias.

This investigation was performed to evaluate the feasibility of detecting repolarization alternans with the heart rate elevated with a bicycle exercise protocol. Sensitive spectral signal-processing techniques are able to detect beat-to-beat alternation of the amplitude of the T wave, which is not visible on standard electrocardiogram. Previous animal and human investigations using atrial or ventricular pacing have demonstrated that T-wave alternans is a marker of vulnerability to ventricular arrhythmias. Using a spectral analysis technique incorporating noise reduction signal-processing software, we evaluated electrical alternans at rest and with the heart rate elevated during a bicycle exercise protocol. In this study we defined optimal criteria for electrical alternans to separate patients from those without inducible arrhythmias. Alternans and signal-averaged electrocardiographic results were compared with the results of vulnerability to ventricular arrhythmias as defined by induction of sustained ventricular tachycardia or fibrillation at electrophysiologic evaluation. In 27 patients alternans recorded at rest and with exercise had a sensitivity of 89%, specificity of 75%, and overall clinical accuracy of 80% (p <0.003). In this patient population the signal-averaged electrocardiogram was not a significant predictor of arrhythmia vulnerability. This is the first study to report that repolarization alternans can be detected with heart rate elevated with a bicycle exercise protocol. Alternans measured using this technique is an accurate predictor of arrhythmia inducibility.

Adolescent↗
PubMed1997

Potency of wild-type or sabin trivalent inactivated poliovirus vaccine, by enzyme-linked immunosorbent assay using monoclonal antibiotics specific for each antigenic site.

Potency testing of inactivated poliovirus vaccine (IPV) is hampered by the absence of a standardized in vitro test, as well as the lack of a generally accepted quantitative animal test. In vitro tests must be able to measure selectively the content of the "D" antigen in the vaccine which includes virus neutralizing antibodies. We tested 12 poliovirus type 1, 12 type 2 and six type 3, D antigen-specific monoclonal mouse antibodies (mAb) for use in the enzyme-linked immunosorbent assay (ELISA). We characterized the site-specific reactivities of three mAbs, one for each poliovirus type. The reactivity of the complete mAb panel encompassed the important antigenic sites on the virus surface of each of the poliovirus serotypes. Some of the mAbs were cross-reactive between wild-type and Sabin strain IPV. At least one mAb of each poliovirus type that was D antigen-specific and reacted with both wild-type and Sabin IPV was directed against an antigenic site thought to be immunogenic in humans. These reagents may be useful for improved standardization of the ELISA for IPV.

Animals↗
PubMed1997

T wave alternans during exercise and atrial pacing in humans.

INTRODUCTION: Evidence is accumulating that microvolt T wave alternans (TWA) is a marker of increased risk for ventricular tachyarrhythmias. Initially, atrial pacing was used to elevate heart rate and elicit TWA. More recently, a noninvasive approach has been developed that elevates heart rate using exercise. METHODS AND RESULTS: In 30 consecutive patients with a history of ventricular tachyarrhythmias, the spectral method was used to detect TWA during both atrial pacing and submaximal exercise testing. The concordance rate for the presence or absence of TWA using the two measurement methods was 84%. There was a patient-specific heart rate threshold for the detection of TWA that averaged 100 +/- 14 beats/min during exercise compared with 97 +/- 9 beats/min during right atrial pacing (P = NS). Beyond this threshold, there was a significant and comparable increase in level of TWA with decreasing pacing cycle length and increasing exercise heart rates. CONCLUSIONS: The present study is the first to demonstrate that microvolt TWA can be assessed reliably and noninvasively during exercise stress. There is a patient-specific heart rate threshold beyond which TWA continues to increase with increasing heart rates. Heart rate thresholds for the onset of TWA measured during atrial pacing and exercise stress were comparable, indicating that heart rate alone appears to be the main factor of determining the onset of TWA during submaximal exercise stress.

Adult↗
PubMed1997

Carbohydrate intolerance after acute gastroenteritis--a disappearing problem in Polish children.

The prevalence of carbohydrate intolerance in Polish children during an acute episode of gastroenteritis was determined. One hundred and seven consecutive children, less than 3 years old, with acute diarrhoea were enrolled into the study. Carbohydrate intolerance (diagnostic criteria: >0.5% reducing substances and stool pH less than 5.5) was diagnosed in 14/107 (13.08%) children: lactose intolerance was present in 12 (11.2%) patients; glucose polymer intolerance in 1 (0.93%) and monosaccharide intolerance in 1 (0.93%). The most important predisposing factor was rotavirus. In all cases the carbohydrate intolerance was transient, resolving within 5 days. Carbohydrate intolerance is also an infrequent problem in Polish children. Restriction of lactose-containing foods (use of lactose-free or low lactose formulas) for the majority of children with gastroenteritis does not seem to be justified.

Age Factors↗
PubMed1997

Exercise-induced T-wave alternans as a marker of high risk in patients with hypertrophic cardiomyopathy.

Microvolt-level T-wave alternans (alternating morphology from beat to beat) during atrial pacing and exercise may predict ventricular tachycardia (VT) and fibrillation (VF) in ischemic heart disease. We tested whether such alternans during exercise could identify high-risk patients with hypertrophic cardiomyopathy (HCM). We studied 14 HCM patients and 9 normal control subjects for T-wave alternans u sing the CH2000 system with 7 multisegment electrodes in a Frank orthogonal (XYZ) configuration. Bicycle ergometer exercise was used to increase the heart rate (HR) to 95-110 beats/min. Seven patients were at high risk for ventricular arrhythmias (1 with sustained VT, 3 with abnormal paced ventricular electrograms as seen in VF survivors, and 3 with nonsustained VT and/or an adverse family history), and the other 7 were at low risk. T-wave alternans was present if alternans > 1.9 microV was consistently present with the HR in excess of a patient-specific HR threshold. Alternans was found in 5 of 7 high-risk patients (71%) vs none of 7 low-risk patients or 9 control subjects (p < 0.025 and p < 0.01, respectively). Notably, all 4 patients with sustained VT or abnormal ventricular electrograms showed alternans. Thus, high-risk patients with HCM often show T-wave alternans. Microvolt-level alternans during exercise may be a useful marker for ventricular arrhythmic risk in patients with HCM.

Adult↗
PubMed1996

Power law behavior of RR-interval variability in healthy middle-aged persons, patients with recent acute myocardial infarction, and patients with heart transplants.

BACKGROUND: The purposes of the present study were (1) to establish normal values for the regression of log(power) on log(frequency) for, RR-interval fluctuations in healthy middle-aged persons, (2) to determine the effects of myocardial infarction on the regression of log(power) on log(frequency), (3) to determine the effect of cardiac denervation on the regression of log(power) on log(frequency), and (4) to assess the ability of power law regression parameters to predict death after myocardial infarction. METHODS AND RESULTS: We studied three groups: (1) 715 patients with recent myocardial infarction; (2) 274 healthy persons age and sex matched to the infarct sample; and (3) 19 patients with heart transplants. Twenty-four-hour RR-interval power spectra were computed using fast Fourier transforms and log(power) was regressed on log(frequency) between 10(-4) and 10(-2) Hz. There was a power law relation between log(power) and log(frequency). That is, the function described a descending straight line that had a slope of approximately -1 in healthy subjects. For the myocardial infarction group, the regression line for log(power) on log(frequency) was shifted downward and had a steeper negative slope (-1.15). The transplant (denervated) group showed a larger downward shift in the regression line and a much steeper negative slope (-2.08). The correlation between traditional power spectral bands and slope was weak, and that with log(power) at 10(-4) Hz was only moderate. Slope and log(power) at 10(-4) Hz were used to predict mortality and were compared with the predictive value of traditional power spectral bands. Slope and log(power) at 10(-4) Hz were excellent predictors of all-cause mortality or arrhythmic death. To optimize the prediction of death, we calculated a log(power) intercept that was uncorrelated with the slope of the power law regression line. We found that the combination of slope and zero-correlation log(power) was an outstanding predictor, with a relative risk of > 10, and was better than any combination of the traditional power spectral bands. The combination of slope and log(power) at 10(-4) Hz also was an excellent predictor of death after myocardial infarction. CONCLUSIONS: Myocardial infarction or denervation of the heart causes a steeper slope and decreased height of the power law regression relation between log(power) and log(frequency) of RR-interval fluctuations. Individually and, especially, combined, the power law regression parameters are excellent predictors of death of any cause or arrhythmic death and predict these outcomes better than the traditional power spectral bands.

Adult↗
PubMed1996

Exercise recordings for the detection of T wave alternans. Promises and pitfalls.

Despite significant advances in the treatment of sudden cardiac death, many individuals still go untreated because routine clinical tests do not identify them to be at risk. Recently, a study to identify individuals at risk has shown that the presence of T wave alternans (TWA), a fluctuation in T wave morphology occurring on an every-other-beat basis, is an accurate predictor of subsequent ventricular tachyarrhythmic events. T wave alternans as low as a few microvolts was found to be significant in predicting risk. Since TWA is often detectable only at elevated heart rates, the study used atrial pacing to increase the heart rate to approximately 100 beats/min. To make TWA measurement more broadly applicable, the authors have developed a methodology that uses noninvasive physiologic stress to raise the heart rate. A particular challenge was the measurement of TWA during exercise, since the levels of noise during exercise can far exceed the levels of TWA. However, by using special multisegment Hi-Res electrodes (Cambridge Heart, Bedford, MA), noise reduction software, and a spectral method of alternans analysis, the authors have been able to reduce noise and reliably measure microvolt-level alternans. This study presents an overview of the methodology for recording and analyzing microvolt-level TWA during ergometer exercise.

Adolescent↗
PubMed1996

Predicting sudden cardiac death from T wave alternans of the surface electrocardiogram: promise and pitfalls.

Sudden cardiac death remains a preeminent public health problem. Despite advances in preventative treatment for patients known to be at risk, to date we have been able to identify, and thus treat, only a small minority of these patients. Therefore, there is a major need to develop noninvasive diagnostic technologies to identify patients at risk. Recent studies have demonstrated that measurement of microvolt-level T wave alternans is a promising technique for the accurate identification of patients at risk for ventricular arrhythmias and sudden cardiac death. In this article, we review the clinical data establishing the relationship between microvolt T wave alternans and susceptibility to ventricular arrhythmias. We also review the methods and technology that have been developed to measure microvolt levels of T wave alternans noninvasively in broad populations of ambulatory patients. In particular, we examine techniques that permit the accurate measurement of T wave alternans during exercise stress testing.

Artifacts↗