The BACTLAB system - a data system for bacteriological routine.

An implemented version of a data system for routine bacteriology is described which uses punch cards to capture all administrative data and OMR (optical mark recognition) documents for the bacteriological findings: diagnosis, antibiotic sensitivity patterns, phage type etc. The output includes reports for the customers and report lists for the laboratory, as well as surveys over findings of pertinent bacteria produced twice each month. In addition bills are produced at regular intervals, both for hospitals and for private patients. All results are stored on magnetic tape in order to make later analysis possible. The system has also been adapted for use in a research project for the study of postoperative infections.     

Invited review: Pharmacogenetics of estrogen replacement therapy.

There are a number of genetic factors that likely modulate both the beneficial and adverse effects of estrogen. An important domain of consideration is the relationship of estrogen and thrombosis risk. Gene polymorphisms among the key elements of the coagulation and fibrinolytic cascade appear to influence the effects of estrogen on risk for venous thromboembolic events and possibly arterial thrombosis as well. Emerging data also suggest that allelic variants in the estrogen receptor-alpha may modulate estrogen's effects, especially with respect to bone and lipid metabolism.     

The principle of adequate design and the cardiovascular system

The principle of adequate design (N. Rashevsky,Mathematical Biophysics, 3rd Ed., Vol. II, Dover Publications, Inc., New York, 1960) is applied to some parts of the cardiovascular system, extending the work of David Cohn (Bull. Math. Biophysics,16, 59–74, 1954;ibid.,17, 219–227, 1955). In addition to the diameterr _a of the aorta and the peripheral resistanceR, calculated by Cohn, other quantities are estimated as to their order of magnitude. It is shown that the specifications of the average metabolic rate lead, from considerations of design, to the possibility of evaluating the orders of magnitude of the average blood pressure, the systolic and diastolic pressures, stroke volume of the heart, duration of the cardiac period and the volume elasticity of the aorta. The calculated values are of the correct orders of magnitude. The purpose of the paper is to illustrate how the application of the principle of adequate design can lead to the evaluation of the above parameters from purely theoretical considerations, rather than from indirect measurements.     

Population need for renal replacement therapy in Thames regions: ethnic dimension.

OBJECTIVES--To determine the use of renal replacement therapy by ethnic origin and to ascertain the variation in provision of such therapy and to relate this to the distribution of ethnic minority populations. DESIGN--Analysis of retrospective and cross sectional data from 19 renal units. SETTING--All four Thames regional health authorities. SUBJECTS--Patients resident in the Thames regions who were accepted as new patients for renal replacement therapy during 1991 and 1992 and the patients who were already undergoing such treatment between December 1992 and April 1993. MAIN OUTCOME MEASURES--Rates of acceptance for and prevalence of renal replacement therapy among white, black, and Asian people. RESULTS--The average annual acceptance rates per million in 1991-2 were 61 for white people, 175 for black people, and 178 for Asians, and the prevalences per million were 351, 918, and 957 respectively. The relative risks increased with age. A threefold increase in the acceptance rate occurred in people aged under 55 in both the black and Asian populations, suggesting that the higher rates are probably not due to factors related to access alone. Treatment rates varied considerably among districts, reflecting both the distribution of ethnic minority populations and access to services. CONCLUSION--Black and Asian people receive and have a greater need for renal replacement therapy, and the need will increase as these populations age. These findings have important implications for the provision of renal services in districts with a high proportion of ethnic minorities and for the management of diabetes mellitus and hypertension, two important causes of end stage renal failure in these populations.     

High-efficiency gene inactivation and replacement system for gram-positive bacteria.

A system for high-efficiency single- and double-crossover homologous integration in gram-positive bacteria has been developed, with Lactococcus lactis as a model system. The system is based on a thermosensitive broad-host-range rolling-circle plasmid, pG+host5, which contains a pBR322 replicon for propagation in Escherichia coli at 37 degrees C. A nested set of L. lactis chromosomal fragments cloned onto pG+host5 were used to show that the single-crossover integration frequency was logarithmically proportional to the length of homology for DNA fragments between 0.35 and 2.5 kb. Using random chromosomal 1-kb fragments, we showed that homologous integration can occur along the entire chromosome. We made use of the reported stimulatory effect of rolling-circle replication on intramolecular recombination to develop a protocol for gene replacement. Cultures were first maintained at 37 degrees C to select for a bacterial population enriched for plasmid integrants; activation of the integrated rolling-circle plasmid by a temperature shift to 28 degrees C resulted in efficient plasmid excision by homologous recombination and replacement of a chromosomal gene by the plasmid-carried modified copy. More than 50% of cells underwent replacement recombination when selection was applied for the replacing gene. Between 1 and 40% of cells underwent replacement recombination when no selection was applied. Chromosomal insertions and deletions were obtained in this way. These results show that gene replacement can be obtained at an extremely high efficiency by making use of the thermosensitive rolling-circle nature of the delivery vector. This procedure is applicable to numerous gram-positive bacteria.     

The treatment of hemophilia A: from protein replacement to AAV-mediated gene therapy

Factor VIII (FVIII) is an essential component in blood coagulation, a deficiency of which causes the serious bleeding disorder hemophilia A. Recently, with the development of purification level and recombinant techniques, protein replacement treatment to hemophiliacs is relatively safe and can prolong their life expectancy. However, because of the possibility of unknown contaminants in plasma-derived FVIII and recombinant FVIII, and high cost for hemophiliacs to use these products, gene therapy for hemophilia A is an attractive alternative to protein replacement therapy. Thus far, the adeno-associated virus (AAV) is a promising vector for gene therapy. Further improvement of the virus for clinical application depends on better understanding of the molecular structure and fate of the vector genome. It is likely that hemophilia will be the first genetic disease to be cured by somatic cell gene therapy.