Rotational displacement of the distal epiphysis of the tibia without fracture.
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Biomedical subjects
Publications and source records attributed to M G Smith.
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We used rep+ and rep- recombinant AAV-plasmid vectors containing the nonselectable marker chloramphenicol acetyltransferase (CAT) driven by the AAV p40 promoter, and having a selectable marker, neo, inserted in the plasmid genome, and driven by a herpesvirus thymidine kinase gene promoter. Each vector was transfected into human 293 cells or HeLa cells and the neo gene was used to select geneticin-resistant (genr) cells containing integrated vectors. The genr cells were then screened for expression of the unselected marker CAT. For 293 cells, most clones from the rep- vector gave high CAT expression whereas only 50% of those from the rep+ vector expressed CAT, generally at low level. For HeLa cells about 25% of the clones derived from either the rep+ or rep- vector expressed CAT, and several clones from the rep+ vector gave very high yields. We also analyzed integrated rep+ vectors by rescue after superinfection with adenovirus and by Southern blotting. The AAV-CAT genome could be rescued from 50% of HeLa cell clones but not from 293 cell clones. Lack of rescuability reflected rearrangement of the AAV genome termini or the rep gene. Western blotting showed low level constitutive expression of rep protein in one 293 cell clone and two HeLa cell clones. Thus, the AAV p40 promoter (as well as p5 and p19) can function in integrated vectors to express unselected markers which can subsequently be rescued. Expression and rescue depended upon several parameters including the cell type, the initial structure of the vector (rep+ or rep-) but not continued expression of rep, and possibly global effects of the surrounding chromatin.
Adeno-associated virus (AAV) vectors readily express the gene for geneticin-resistance under control of the AAV p40 promoter when chromosomally integrated at low copy number in mammalian cells. We show that a truncated AAV rep gene, transcribed from the p5 and p19 promoters, mediates a negative effect on expression of geneticin-resistance in human 293 cells and a positive effect in HeLa cells. Also, we describe a novel phenotype for a mutant expressing the p19 rep gene alone which has a negative effect in 293 cells but no positive effect in HeLa cells.
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Samples of blended mutton tissue in small polyvinyl chloride sachets were incubated in water baths for different times and at varying temperatures. The temperature of each bath was recorded accurately throughout each experiment. Using equations previously derived for the lag and generation times of coliform organisms in blended mutton tissue, the expected increases of these bacteria were calculated from the time/temperature recordings. These were compared with the data obtained from plate counts made on the tissue samples in the sachets before and after incubation. The studies were done with a strain of Escherichia coli, one of Salmonella typhimurium and the coliform organisms naturally present on sheep carcasses processed in a commercial abattoir. The calculated growth agreed closely with that measured. Therefore, if mutton, after overnight chilling, is warmed again to temperatures within the growth range of these bacteria, the possible increases in the numbers of cells present can be calculated directly from time and temperature measurements. The implications for the present codes of practice in abattoirs are discussed.
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Two girls with congenital postural deformity of the wrist associated with deformity of the feet are reported. Fetal position in utero is discussed as a likely cause, and treatment by simple manipulation is recommended.
The growth of coliform organisms on meat tissue from sheep carcasses processed in a commercial abattoir was investigated. The results indicated that for practical purposes the minimum temperature of growth of these organisms on meat may be taken as 8 degrees C. Equations were derived relating the generation time and the lag time of coliform organisms in raw blended mutton to the temperature at which the meat is held. Estimates of growth obtained with these equations were found to agree closely with the experimental results, especially at temperatures above 10 degrees C, and allowed the generation times and the lag times for all temperatures up to 40 degrees C to be calculated. These times were also found to agree closely with the times determined using a strain of Escherichia coli inoculated into blended mutton tissue. A strain of Salmonella typhimurium inoculated in the same way into blended mutton tissue gave longer generation and lag times at temperatures below 15 degrees C. Therefore, it is believed that the calculated tables of lag and generation times included in this paper can be used to determine the length of time raw chilled meat may be held afterwards at temperatures above the minimum temperature of growth without an increase in the number of any salmonella organisms present, and these times include a safety margin at each temperature. The study indicates that the mandatory codes of practice presently applied in commercial abattoirs are too stringent. Maintaining the temperature of boning rooms at 10 degrees C or less does not appear to be necessary providing the meat is processed within the calculated time limits. A relaxation of the restrictions on boning room temperatures would decrease costs, increase worker comfort and safety and would not compromise the bacteriological safety of the meat produced.
We describe the construction of an adeno-associated virus (AAV) vector in which the coding sequence of the procaryotic gene neo is expressed under the control of the major AAV promoter p40. This AAV-neo vector allowed stable expression of neo as a dominant selective marker in mammalian cells by selection of cells which were resistant to the antibiotic geneticin (G418). When the vector was introduced into human (293 or HeLa) cell lines by a DNA transfection procedure, stable geneticin-resistant colonies were obtained. When the vector was first packaged into AAV particles and then introduced into cells via particle infection, geneticin-resistant cells were obtained at higher frequencies than those obtained by DNA transfection. In geneticin-resistant cells the AAV-neo vector was integrated at low copy number and could be rescued by subsequent infection with wild-type AAV and the helper adenovirus or, in some cases, by infection with adenovirus alone. The rescued AAV-neo vector could then be recovered as amplified unintegrated DNA from a Hirt lysate. These results demonstrate that AAV can be used as a transducing viral vector for stable integration and expression of a foreign gene in mammalian cells. The high frequency of integration and the ability to rescue the integrated vector suggest that this vector system may be useful for selecting genes from cDNA libraries. This vector may also be useful for introduction of genes into cells which are refractory to transfection in procedures such as those involving the use of CaPO4 or DEAE-dextran.
The Automated Portable Test (APT) System is a notebook-sized, computer-based, human-performance and subjective-status assessment system. It is now being used in a wide range of environmental studies (e.g., simulator aftereffects, flight tests, drug effects, and hypoxia). Three questionnaires and 15 performance tests have been implemented, and the adaptation of 30 more tests is underway or is planned. The APT System is easily transportable, is inexpensive, and has the breadth of expansion options required for field and laboratory applications. The APT System is a powerful and expandable tool for human assessment in remote and unusual environments.
An extensive study of the plumbing systems in Kingston Hospital was made over the three years following the 1980 outbreak of legionnaires' disease. The introduction of chlorination and raising the water temperature controlled the outbreak but failed to decontaminate water outlets in the wards. Legionella pneumophila was isolated from rubber washers in shower fittings, and laboratory experiments demonstrated the ability of L pneumophila to grow in water in contact with these rubber components. All the components in the hospital's fittings were replaced with an approved type, and since then L pneumophila has not been isolated from water or components.
The purposes of the present investigation were: (1) to describe the relationships between exercise pulmonary ventilation (VE) and oxygen uptake (VO2) and VE and carbon dioxide production (VCO2), (2) to determine the % VO2 max at the lowest ventilatory equivalent of oxygen (VEO2), and (3) to examine the relationship between the % VO2 max at the lowest VEO2 and maximal aerobic power (VO2 max). During incremental load work, VE increased exponentially in relation to elevations in VO2 and VCO2. Differentiation of the VE to VO2 exponential equation gives the minimum slope of the equation and corresponds to the lowest ventilatory equivalent for oxygen. In our subjects, VO2 max (mean +/- SD) was 3.84 +/- 0.71 l . min-1, and VO2 at the lowest VEO2 was 1.70 +/- 0.32 l . min-1. The VO2 at the lowest VEO2 was 44.3 +/- 4.0% VO2 max (range 37% to 53% VO2 max). The correlation coefficient (r) between VO2 at the lowest VEO2 and VO2 max was 0.90, while the r between % VO2 max at the lowest VEO2 and VO2 max was -0.24.
Of 103 neonates with congenital dislocation of the hip in a consecutive personal series, 100 were treated with a standard divaricator splintage regimen; of these, the result is known in 97. In three babies with irreducible dislocation no treatment was attempted. In 90 babies the hips became normal. In one hip dislocation persisted; in three osteochondritis with femoral growth plate damage developed without obvious cause; and in two hip dysplasia responded to surgical correction of femoral anteversion. In one baby attempted treatment of irreducible hips produced a poor result. The practice of treating all hips found to be unstable at orthopaedic examination but not those previously suspected but later unconfirmed is defended.
Examination of some previously isolated bile acid-utilizing Pseudomonas strains showed that Pseudomonas sp. ATCC 31752, together with other fluorescent strains, can be assigned to Pseudomonas putida biotype B, whereas Pseudomonas sp. ATCC 31753, like most other nonfluorescent strains, is an unrecognized phenotype. A study was made of the growth of these two species at 25 degrees C and pH 7.0 in a fermentor with 2.5 g of sodium cholate liter-1 as sole carbon source, and the catabolism of the cholate and its products was followed by high-pressure liquid chromatographic and thin-layer chromatographic examination. At aeration rates of either 150 or 5 ml min-1 liter-1, growth of each species followed the same catabolic pathway. 7 alpha, 12 beta-Dihydroxy-1,4-androstadiene-3,17-dione was the major catabolite formed, with 0.3 g liter-1 being the maximum concentration that accumulated at the higher aeration rate, whereas 1.4 g liter-1 accumulated at the lower aeration rate, irrespective of the species used. The latter yield is sufficiently high to be of potential commercial value if such a catabolite were found to be economically useful for steroid drug manufacture. It is postulated that the rate-limiting step in cholic acid catabolism by these species at the lower aeration rate is 9 alpha-hydroxylation, a step requiring molecular oxygen, hence, the marked effect of oxygen limitation on catabolite accumulation. Another consequence of oxygen limitation is the production of a red pigment in the culture medium, which, however, does not affect catabolite recovery.
The effects of diet and exercise on serum triglycerides (Trig), total cholesterol (TC), low density lipoprotein cholesterol (LDL), high density lipoprotein cholesterol (HDL), and the HDL to TC ratio (HDL/TC) were evaluated in 45 men training continuously for a duration of 6 months. Body mass index (BMI), percentage body fat, and serum values for Trig, TC, HDL, and HDL/TC were constant throughout the observation period. Bivariate correlations indicated that Trig, TC, and LDL were linearly related and HDL and HDL/TC were related to HDL and HDL/TC. Multiple regression analysis suggested that BMI was the best predictor of Trig, TC, and LDL, while distance run per month was the best predictor of HDL and HDL/TC and second best predictor of Trig. The weekly intakes of fish, bread, cooked cereal, wine, beer, soft drinks, and vegetables were less significant predictors of lipoprotein levels.
In a cross-sectional study of Hopi and Navajo Indians with non-insulin-dependent diabetes mellitus, we found vascular complications to be strongly related to the duration of diabetes. In patients with diabetes of at least 10 yr duration, retinopathy was found in 57%, nephropathy in 40%, peripheral neuropathy in 21%, and peripheral vascular disease in 28%. For the Hopi and Navajo, the duration-specific prevalence rates of microvascular disease were very similar to prevalence rates found in many other populations. Thus we question the concept, based on reports in the late 1960s, that the Hopi and Navajo Indians have hyperglycemia as an isolated chemical abnormality unaccompanied by other manifestations of diabetes mellitus.
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Various RNA fractions were isolated from nuclei of 12-day lactating rat mammary glands and examined for their ability to inhibit cell-free protein synthesis. Although total nuclear RNA was generally inactive, material contained in the poly(A)+ nuclear RNA fraction and the low-molecular-weight RNA derived from total nuclear RNA by sucrose gradient centrifugation, inhibited the translation of several mRNAs but not poly(U) or poly(A). Separation of the small nuclear RNAs by preparative polyacrylamide-urea gel electrophoresis allowed the identification of at least three active inhibitor RNA species. These differed both with respect to their ability to inhibit protein synthesis, and in their mechanism of action. While two of the RNA species inhibited elongation the other inhibited initiation of protein synthesis.