A large-scale automated method for hepatocyte isolation: effects on proliferation in culture.

Large-scale sterile methods for isolating hepatocytes are desirable for the development of bioartificial liver support systems. In this study the traditional centrifuge method was compared with the use of a Baylor Rapid Autologous Transfusion (BRAT) machine for isolating large quantities of porcine hepatocytes. After isolating hepatocytes, the methods were evaluated in terms of cell viability and yield per liver, proliferation over 7 days, and the effects on the cell cycle using the trypan blue exclusion test, conventional phase-contrast light microscopy, the lactate to pyruvate ratio, the leakage of lactate dehydrogenase (LD) and aspartate aminotransferase (AST), lidocaine clearance, albumin production, and flow cytometry. With the centrifuge method the mean cell viability was 92.5%, while with the BRAT method the viability was 95.9%. The minimal cell yields with the BRAT procedure were 7.3 x 10(9) for 250-ml centrifuge bowls and 2.8 x 10(9) for 165-ml bowls, which compares well with that found by other authors. Because the same initial procedures were employed in both methods the total hepatocyte yield per liver was comparable. Flow cytometry confirmed that the proliferation of hepatocytes was facilitated by oxygenation during the isolation procedure. The recovery of hepatocytes in culture following isolation was similar after either method. Daily microscopic investigation indicated that cytoplasmic vacuolization and granularities were present after either procedure and these disappeared following 3-4 days of culturing. Flow cytometry indicated that the hepatocyte cell cycle was similar after either method; at 7 days the profile indicated that the cells were still proliferating. Trends in the lactate to pyruvate ratio and the leakage of LD and AST indicated that the functional polarity of hepatocytes was regained after approximately 3 days. Lidocaine clearance at 4 days indicated that the cytochrome P450 system was active, while significant albumin production was apparent at day 5. The benefit of using BRAT technology in hepatocyte isolation lies in guaranteed sterility, convenience, speed, and the ability to oxygenate media and cell suspensions during the procedure.

[Patient activity level plans for personnel scheduling in nursing in-patient units]. / N plan vir die bepaling van pasiëntakuutheidsvlakke vir verpleegkundige postebepaling.

This study of patient activity level plans (PALP) to determine nursing levels for in-patients units was carried out by means of an exploratory, descriptive instrumental study within the context of a nursing situation. With the literature study serving as background, a patient activity level plan (PALP) was designed, according to accepted criteria, to find data on which to base post determination of nursing staff. This study was done at a private research hospital in Johannesburg where all the patients and nursing staff (first- as well as second-in-charge) were involved. The PALP-instrument was designed by the researcher, and under supervision of the researcher it was implemented in seven nursing units in the hospital. (The instrument proved to be highly reliable p = 0.999). The difference between nursing post determination as recommended and determined by PALP, and nursing post determination as determined by means of a pragmatic subjective approach by the nursing service manager of the hospital, proved to be statistically insignificant. The PALP instrument showed, however, that more nursing staff were needed in four of the seven units. The quality of the nursing care was not investigated nor was a productivity study carried out. The total difference between the recommended and actual nursing hours needed for all the nursing units shows a statistically significant difference (p = 0.0001) on a 1% significance level. The instrument proved to be easily comprehended, easily implemented and relevant to its purpose. It also shows a high inter-rator reliability (a chronbach alpha value of 0.999). Thus a reliable PALP-instrument was developed and successfully implemented at a research hospital for the determination of nursing posts. The most significant recommendations include national standardization of the PALP-instrument in hospitals and refining and testing of the PALP-instrument in other clinical areas e.g. out-patients and critical care units. This instrument could also contribute towards a more cost-effective post determination in nursing.

99mTc ethoxy methylpropyl isonitrile: a radioactive tracer for myocardial perfusion imaging.

The initial experience with a new 99mTc labelled myocardial perfusion agent, ethoxy methylpropyl isonitrile (EMI), is described in the primate as model. Rapid biliary clearance of EMI ensures low radionuclide concentration in the liver and lungs after 60 min. Adequate visualization of the myocardium is therefore possible. Heart-to-lung and heart-to-liver ratios of 1.52 and 2.45 respectively were obtained. EMI is an efficient imaging agent to evaluate myocardial ischemia and infarction.

Evaluation of (o)-[77Br]bromohippuran as renal tubular function agent.

(o)-[77Br]bromohippuran (BHIP) was developed as renal tubular function agent due to its favourable chemical and physical properties and compared to (o)-[131I]iodohippuran (IHIP). Renograms obtained from baboons were compared and absorbed radiation dose calculations performed. Although BHIP showed a delayed kidney uptake and washout pattern, good kidney clearance of the radionuclide was obtained after 30 min. Radiation dose values for BHIP were markedly lower than for IHIP indicating that larger activities of BHIP could be administered to increase counting statistics. BHIP imaging in normal volunteers did however not substantiate the favourable behaviour obtained in the primate.

Synthesis of five new 99mTc-HIDA isomers and comparison with 99mTc-HIDA.

Five new HIDA-compounds were synthesized, labelled with 99mTc and compared with 99mTc-(2,6-dimethyl)HIDA viz. (N-2,6-dimethylphenylcarbamoylmethyl)iminodiacetic acid by means of TLC and biodistribution studies on rabbits. The computerized method used by Britton and Brown during renal studies was successfully adapted to study the biodistribution of these agents.

Antibiotic-resistant Serratia marcescens infection in a hospital.

Over a 12-month period, 74 isolates of Serratia marcescens were obtained from various sources at Tygerberg Hospital. The majority of these isolates were from catheterized patients with urinary tract infections, and were non-pigmented and resistant to all antibiotics tested, excepting amikacin and neomycin. All isolates transferred resistance to tobramycin, gentamicin and tetracycline by conjugation to Escherichia coli recipients as separate markers at low frequency. A non-self-transmissible plasmid conferring resistance to kanamycin, ampicillin and gentamicin was mobilized from Serratia species to E. coli, and became fully self-transmissible in subsequent matings.