Genetic differentiation between and within strains of the saw-toothed grain beetle, Oryzaephilus surinamensis (Coleoptera: Silvanidae) at RAPD loci

Nine strains of Oryzaephilus surinamensis have been kept in laboratory culture for periods ranging from 5 to 30 years (30–180 generations). Two RAPD primers provided sufficient information to separate the strains reliably and unambiguously. The strains are maintained at a population size of 200 breeding adults. The marked divergence between strains is consistent with the small population size, which for the older strains, according to population genetics theory, implies that roughly half the original genetic variation should now be lost from within strains. However, there is no indication that the older strains have less inter-strain variation. The results demonstrate RAPD loci can reliably detect population subdivision, which in field populations of pest species is of fundamental importance in understanding the population genetics of insecticide resistance.     

The role of arthroscopy in the problem total knee replacement

Fourteen patients were retrospectively reviewed to examine the role of arthroscopy in the diagnosis and treatment of the problem total knee arthroplasty (TKA), and to define parameters for indications, techniques, and results. All patients had undergone a previous TKA, and postoperatively had problems with pain and/or range of motion. Routine evaluation failed to reveal sepsis or aseptic loosening. Arthroscopy was used to evaluate and treat certain specific conditions. The arthroscope was successful in removing loose bodies, correcting patella subluxation with an arthroscopic lateral release, excising a symptomatic pseudomeniscus, and releasing intraarticular adhesions to improve motion and relieve pain. The postoperative knee score improved 73%. Arthroscopy is a valuable tool to evaluate a painful TKA, and can be used to treat certain conditions that would otherwise require an arthrotomy. The rehabilitation time is easier on the patient and much quicker. Arthroscopy of a TKA does not compromise any future procedures. However, it remains a technically demanding procedure whose indications and expectations are still being defined.     

Simultaneous determination of sulfasalazine and its metabolites sulfapyridine and N-acetylsulfapyridine in human serum by ion-pair high-performance liquid chromatography using a polymer-based column

An HPLC method is described for the simultaneous and rapid determination of sulfasalazine (salicylazosulfapyridine) and two of its metabolites, sulfapyridine and N-acetylsulfapyridine, in human serum. The range of quantitation is 0.1 to 12 micrograms/mL for sulfasalazine and sulfapyridine and 0.25 to 12 micrograms/mL for N-acetylsulfapyridine. Serum is mixed with acetonitrile containing the internal standard sulfamethazine and the ion-pairing agent tetraethylammonium chloride. The acetonitrile extract is concentrated and analyzed by HPLC, using a new polymer-based column, and detected by UV spectroscopy at 270 nm. This paper is the first both to describe the simultaneous analysis of all three of the compounds from serum and to present sulfasalazine concentration-time data following oral administration to humans.     

Diagnosis of traumatic cardiac contusion

Cardiac contusion following blunt chest trauma remains a diagnostic problem because of a lack of sensitive diagnostic tests. This study evaluated thallous chloride Tl 201 single-photon-emission computed tomography in a series of 48 patients following blunt chest trauma. Of the 48 patients, 23 had normal scans. None of these patients proved to have serious arrhythmias during three days of continuous monitoring. Of 25 patients with abnormal or ambiguous studies, five (20%) developed serious arrhythmias requiring therapy. Single-photon-emission computed tomography scanning thus was sensitive in indicating that group of patients at risk of serious arrhythmias, and may therefore prove to be a useful screening test to determine the need for hospitalization and arrhythmia monitoring following blunt chest trauma.     

The logical structure and validity of experimental designs in pharmacokinetics and clinical pharmacology

Much of the literature on research design in clinical pharmacology and pharmacokinetics emphasizes statistical concerns, thus suggesting that a primary ingredient of a valid research design is an appropriate plan for statistical analysis of data. However, statistical validity is only one of several ways to evaluate an experimental study. The present paper reviews the underlying logic and sources of invalidity of experimental drug research suggesting influences and factors which may deceive or lure an experimenter into erroneous conclusions.