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Biomedical subjects

J F Huber

Publications and source records attributed to J F Huber.

At least 19 recordsLinked to original sources
PubMed1995

Assay of neopterin in serum by means of two-dimensional high-performance liquid chromatography with automated column switching using three retention mechanisms.

An automated two-dimensional HPLC method for the determination of neopterin in serum is described. Neopterin is separated from proteins on a short octadecylsilica column by size exclusion and from the majority of the other serum components by adsorption. The fraction containing neopterin is transferred by column switching to a solvent-generated cation-exchange column using dodecylsulfonic acid as surface activator. Parameters influencing the separation performance and sensitivity of the fluorescence detection are discussed. The efficiency of the cleaning of the first column was optimized. The method was validated. It achieves a precision of 1% (R.S.D.) and a detection limit of about 0.3 nmol/l. The accuracy is nearly 100%. The method allows a high sample throughput, requiring 15 min per sample.

Automation↗
PubMed1995

Joint infections due to Listeria monocytogenes: case report and review.

Joint infections of bone are unusual manifestations of listerial infection. Fourteen cases of septic arthritis due to Listeria monocytogenes have been previously described in adults. We report the 15th case of septic arthritis due to Listeria in which bilateral prosthetic hips in a renal transplant patient were involved. In addition, we review the literature on listerial joint infections.

Adult↗
PubMed1986

[Multicenter experiences with the intracervical administration of a new PGE2 gel in labor induction].

With the participation of four Swiss obstetric clinics, medically indicated inductions of birth (with living fetuses) were performed using a new, stable PGE2 gel, and documented according to a uniform protocol. The study was conducted to investigate the efficacy of 0.5 mg of PGE2, in 2.5 ml of a vehicle (Triacetin) not yet commercially available, for local cervical maturation (n = 41). Thirty-nine patients selected by prospective randomization, in whom birth was induced conventionally, served as a control group. The efficiency of the prostaglandin gel alone or respectively with additional administration of oxytocin was evaluated on the basis of the clear changes in the cervical findings observed within 12 or respectively 24 hours, the spontaneous births, or, in the case of cesarean deliveries, according to the pelvic score. Application of PGE2 alone led to impressive changes of the cervix score and, in 34 of the 41 cases, to regular contractions after an average time of 87 minutes. After 12 hours, prior to administration of oxytocin, 43% of the patients were already delivered. The combination of locally applied PGE2 gel with conventional oxytocin induction significantly increases the number of successful inductions. The percentage of unsuccessfully attempted inductions was reduced to 24% in the PGE2 gel group as compared to 44% in the control group.

Adolescent↗
PubMed1983

Are vaginal fluid concentrations of prolactin, alpha-fetoprotein and human placental lactogen useful for diagnosing ruptured membranes?

Vaginal fluid levels of prolactin (Prl), alpha-fetoprotein (AFP) and human placental lactogen (hPL) were assayed to investigate their usefulness in the diagnosis of ruptured membranes. Fifty-two patients at term were divided into those with intact membranes, and those with ruptured membranes. In patients with intact membranes the concentration of all three substances was low with few exceptions. The mean vaginal concentrations of the three proteins were significantly higher in patients with ruptured membranes, but low values were also found in this group. It is concluded, that because of the overlap between the values, Prl, AFP and hPL measurements in vaginal fluid do not represent a useful advance in the assessment of rupture of the membranes.

Body Fluids↗
PubMed1979

Quantitation of the information content of multi-dimensional gas chromatography and low-resolution mass spectrometry in the identification of doping drugs.

On the basis of information theory, a comparison of the performance of the identification of compounds by multi-dimensional gas chromatography and binary-encoded low-resolution mass spectrometry is made for doping drugs. This group of compounds was not selected at random but according to their pharmocological effects. For these compounds it was observed that the m/e values of the peaks in the mass spectra are highly correlated, while a number of chromatographic columns can be found on which the retention data are only slightly correlated. As a result, the information content of two-dimensional gas chromatographic retention data on such columns equals the information content of binary-encoded low-resolution mass spectra. It is shown that the accuracy and precision of retention data in gas--liquid chromatography, and therefore the information content, can be significantly improved if the data are corrected for adsorption effects of the solid support and extrapolated to a limiting value in the case of asymmetric peaks.

Central Nervous System Stimulants↗
PubMed1979

[Determination of carbamate pesticides in fruits and vegetables by means of high pressure liquid chromatography (author's transl)].

It is shown that carbamate pesticides can be determined at the ppm level in different kinds of fruits and vegetables using high pressure liquid chromatography. The lower detection limit corresponding to a signal to noise ratio of three is between 0,025 and 0,25 ppm depending on the type of carbamate and plant material. In all cases it is below the maximum permissible value for pesticide residues. Due to the high separating power of high pressure liquid chromatography a simple sample pretreatment procedure can be used. The carbamates are extracted from the biological sample by dichloromethane and injected directly into the liquid chromatograph after replacing the extraction solvent by the mobile phase. In many cases a definite identification and quantitation of the carbamate is possible with a single chromatographic column. Some plants with a more complex matrix require a two-column operation in which the effluent fraction of the first column containing the pesticide is transferred by column switching to a second column in order to achieve a complete separation. The improved resolution in the two-column operation is caused by the relative enrichment effect of the fractionation and the increased column length.

Carbamates↗
PubMed1978

[Quality of life and the subjective well-being after successful kidney transplantations].

The quality of life following kidney transplantation is examined. For this reason a total of 38 patients were questioned. There were three subgroups: 18 adults and 10 children with excellent kidney function and 10 patients in whom nephrectomy had to be performed after rejection of the transplanted organ. The extent and importance of the changes of various criteria considered essential for judgement of the quality of life are illustrated. Adults and children alike consider the improvement of drinking and eating habits, improvement of physical fitness and of the capability to deal with psychological problems as the essence of their greater joy in life. For children there are added advantages at school and in the choice of their occupational activity. In conclusion there is a definite improvement of the quality of life following renal transplantation.

Adult↗
PubMed1977

Improvement of the efficiency of ion-exchange cellulose columns and their application.

Packing procedures and operating conditions for microparticulate ion-exchange cellulose columns were investigated. The efficiencies of ion-exchange cellulose and mixed-bed ion-exchange cellulose columns were compared. The mixed-bed columns contained ion-exchange cellulose and diatomite, and those with a 5:1 volume ratio of ion-exchange cellulose (average particle size 7 micronm) and diatomite were found to be superior in almost every respect. Medical, pharmaceutical, biochemical and environmental applications of this type of column are shown.

Cellulose↗
PubMed1977

Separation of estrogen glucorinides, sulphates and phosphates on ion-exchange cellulose by high-pressure liquid chromatography.

In continuation of previous work, the selectivity of anion-exchange cellulose systems with respect to thirty estrogen conjugates was studied. The influence of the type and particle size of cellulose anion exchangers, the type and concentration of the counter anion, pH and temperature was investigated. On the basis of the results the optimal choice of the ion-exchange material, the eluent and the operating conditions is demonstrated. The results of the optimization are exemplified by a number of chromatograms showing rapid separations, including the determination of the estrogen conjugate profile of human pregnancy urine.

Cellulose↗
PubMed1977

Rapid trace analysis of barbiturates in blood and saliva by high-pressure liquid chromatography.

The performances of a number of liquid--solid systems, consisting of mixtures of water and methanol as liquid phase and methyl silica as solid phase, were investigated with respect to their use in the separation of barbiturates by high-pressure liquid chromatography (HPLC). Phase system selectivities and column efficiencies were determined. The results were applied to the development of a rapid method for the determination of trace amounts of barbiturates in blood. The first step in the analysis, the extraction of barbiturates from blood, was also investigated and good recoveries were achieved. The extracts were analyzed by HPLC using ultraviolet detection at 220 nm. A low detection limit and high precision were obtained; An amount of 5 ng hexobarbital, for example, can be determined with a precision of +/-15% and 5 mug with a precision of +/-0.3%. The time course of the concentration of hexobarbital in the serum and saliva of man after an oral administration of 400 mg is demonstrated.

Autoanalysis↗