Multicenter evaluation of the performance and clinical utility in longitudinal monitoring of the Bayer Immuno 1 complexed PSA assay.

We conducted a multicenter evaluation of the analytical and clinical performance of the automated Bayer Immuno 1 complexed PSA (cPSA) assay, and compared assay performance to the Bayer Immuno 1 PSA assay. We sought to determine whether measurements of cPSA could be of clinical utility in the management of patients with prostate cancer. Results of the 10-day imprecision across three evaluation sites produced total CV < 2.50% and an analytical sensitivity of 0.02 microgram/L. There was an increased trend in clinical sensitivity for prostate cancer with increasing stage of disease (71-86%). Clinical specificity for patients with benign urogenital disease was 74.8%, and for other nonprostate diseases ranged from 91.1-100%. Retrospective serial monitoring of 155 patients with prostate cancer demonstrated concordance of cPSA measurements to clinical status for 97% of the patients analyzed. Results from the clinical studies using the Bayer Immuno 1 cPSA assay were comparable to results obtained with the Bayer Immuno 1 PSA assay. The Bayer Immuno 1 cPSA assay demonstrates analytical performance and clinical effectiveness in the management of prostate cancer patients during the course of disease and therapy.     

Effect of Cimetidine and other antihistaminics on the elimination of aminopyrine,phenacetin and caffein

Cimetidine is widely prescribed for the treatment of peptic ulcer disease and has recently been shown to inhibit the metabolism of warfarin, antipyrine and diazepam. To further examine this phenomenon we investigated the effect of various doses of cimetidine and other related drugs on ¹⁴C-aminopyrine, ¹⁴C-phenacetin and ¹⁴C-caffeine breath tests. Cimetidine caused a dose-related inhibition of the metabolism of aminopyrine and caffeine but had no effect on the phenacetin breath test. Metiamide, H₁-antihistamines, phenothiazines and local anesthetics also inhibited the aminopyrine breath test. Cyproheptadine had no effect on either phenacetin or caffeine elimination. This study demonstrates a complex drug-drug interaction which may have widespread clinical implications.     

Near-infrared spectroscopy for bioprocess monitoring and control.

This article describes the calibration of a spectroscopic scanning instrument for the measurement of selected contaminants in a complex biological process stream. Its use is for the monitoring of a process in which contaminants are to be removed selectively by flocculation from yeast cell homogenate. The main contaminants are cell debris, protein, and RNA. A low-cost instrument has been developed for sensitivity in the region of the NIR spectrum (from 1900 to 2500 nm) where preliminary work found NIR signatures from cell debris, protein, and RNA. Calibration models have been derived using a multivariate method for concentrations of these contaminants, such as would be found after the flocculation process. Two strategies were compared for calibrating the NIR instrument. In one case, samples were prepared by adding materials representative of the contaminants to clarified yeast homogenate so the contaminant levels were well known but outside the range of interest. In the other case, where samples were like those from the process stream after flocculation and floc removal, there was uncertainty of analysis of contaminant level, but the calibration was in the range of interest. Calibration using process stream samples gave results close to those derived from traditional assays. When the calibration models were used to predict the contaminant concentrations in previously unseen samples, the correlation coefficients between measurements and predictions were above 90% in all cases but one. The prediction errors were similar to the errors in the traditional assays.     

Transitions: Homo erectus and the Acheulian: the Ethiopian sites of Gadeb and the Middle Awash

Significant differences in activity-site patterning and artifact composition at Middle Pleistocene localities in Ethiopia's high plains and Afar Rift are indications of both single-episode, small-site residues from small groups and multi-purpose, multiple occupation sites from which larger, temporary groupings might be inferred. Reconstructions of palaeo-environments and geography show that large assemblages relate to relatively stable topography, such as stream channels or lake margins, while small assemblages are more common in deltaic situations of rapid sedimentation and burial in the Rift that preclude possibility of reoccupation. A model for Acheulian socio-economic behaviour within the drier African savanna, based (in part) on chimpanzee behaviour in open savanna habitats, is proposed. This takes the form of organization into relatively extensive territories, each with several more closed-vegetation core areas, of limited extent close to permanent water, surrounded by more extensive areas of drier, open savanna, regularly exploited and patrolled by small groups. Movement from one core area to another was rapid and made together as a group, to minimize danger from large predators and competition from other hominid groups.     

Determination of free and esterified cholesterol in human serum by high-performance liquid chromatography and optical activity detection

A separation and detection scheme is presented for the determination of free, esterified and total cholesterol in human serum. Separation is accomplished by reversed-phase high-performance liquid chromatography and the eluate is monitored by the laser-based optical activity detector. The method is simple, accurate and has the advantage of specificity and selectivity when compared with the many methods commonly used.     

High-Throughput Nonlinear Optical Microscopy

High-resolution microscopy methods based on different nonlinear optical (NLO) contrast mechanisms are finding numerous applications in biology and medicine. While the basic implementations of these microscopy methods are relatively mature, an important direction of continuing technological innovation lies in improving the throughput of these systems. Throughput improvement is expected to be important for studying fast kinetic processes, for enabling clinical diagnosis and treatment, and for extending the field of image informatics. This review will provide an overview of the fundamental limitations on NLO microscopy throughput. We will further cover several important classes of high-throughput NLO microscope designs with discussions on their strengths and weaknesses and their key biomedical applications. Finally, this review will close with a perspective of potential future technological improvements in this field.     

Post-translational processing of the porcine gastrin precursor by phosphorylation of the COOH-terminal fragment

The gene sequence encoding porcine preprogastrin is known; in order to clarify pathways of post-translational processing of the predicted precursor peptide we have characterized material reacting with antibodies to a synthetic peptide corresponding to the expected extreme COOH-terminal portion of the precursor. Radioimmunoassay was used to identify and monitor the purification of peptides in porcine antral mucosa. Two peptides (I and II) were isolated to homogeneity by steps involving gel filtration, ion exchange, and reversed-phase high performance liquid chromatography. The two co-eluted on gel filtration but were separated on anion-exchange chromatography. The more acidic peptide (II) was less hydrophobic on high performance liquid chromatography. Automated gas-phase microsequencing revealed the less acidic peptide (I) to have the sequence of porcine preprogastrin 96-104 (SAEEGDQRP); it would be produced by tryptic-like cleavage of Arg95-Ser96. The second peptide did not yield a phenylthiohydantoin-derivative on the first cycle but thereafter it sequenced as the first peptide (i.e. -AEEGDQRP). Incubation in alkali liberated almost equimolar amounts of phosphate from peptide II but not from I. In addition, alkaline phosphatase liberated phosphate and converted the acidic peptide to the less acidic one. The results suggest that serine in the first position is phosphorylated in peptide II but not I. The tripeptide -Ser(P)-Ala-Glu- also occurs in adrenocorticotropic hormone; this tripeptide is a substrate for physiological casein kinase. Potential phosphorylation sites occur at comparable positions in the precursors of a number of regulatory peptides.     

The mitochondrial outer membrane channel, VDAC, is regulated by a synthetic polyanion

A synthetic polyanion has been found to modulate the properties of the mitochondrial outer membrane channel, VDAC. This 10 kDa polyanion, first synthesized and described by Konig and co-workers, is a 1:2:3 copolymer of methacrylate, maleate, and styrene. It had been shown to interfere with the access of metabolites to the mitochondrial inner spaces. Here we show that, at nanomolar levels, the polyanion increases the voltage dependence of VDAC channels over 5-fold. Some channels seem to be totally blocked while others display the higher voltage dependence and are able to close at very low membrane potentials (5 mV). At 27 micrograms/ml polyanion, VDAC channels are closed while inserted into liposomes in the absence of any applied potential. The closed state of VDAC induced by the polyanion has similar properties to the closed state induced by elevated membrane potentials. The physical size of the polyanion-induced closed state (in VDAC-containing liposomes) is about 0.9 nm in radius. How this estimate fits with estimates of the channel's open state and estimated volume changes between the open and closed states, is discussed.