Continuity of care: does it contribute to quality of care?

Continuity of care is defined and measured in terms of care received from a single physician, from several physicians practicing as a group and from physicians seen through referrals. All patients receiving tonsillectomy and adenoidectomy (T and As) in Manitoba for one year, as well as a group of similar individuals treated with respiratory illnesses but not having T and As, were studied. Several patient and physician characteristics were examined to determine their relationship to continuity of care. Continuity consistently increased with patient age, but appeared unrelated to several other variables. The links between continuity of care and quality of care were explored using process and outcome measures of quality. A cross-lagged panel analysis suggested no casual relationship between continuity and quality. These results contradict those of several other studies; they are important in that continuity of care is shown not to reduce one type of error of commission made by practitioners.

Genetic effects of chlorinated anilines and azobenzenes on Salmonella typhimurium

The mutagenicity of 19 herbicide-derived chlorinated azobenzenes and structurally related chlorinated anilines and nitrobenzenes was assayed towards several strains of S. typhimurium, using the plate incorporation method and the fluctuation test, in the presence or in the absence of liver post-mitochondrial fractions, in aerobic and anerobic conditions. Positive results were obtained with 4,4'-dichloroazobenzene, 4,4'-dichloroazoxybene, 3,4-dichloronitrobenzene and, to a much lesser extent, with 3,4,3',4'-tetrachloroazobenzene. No mutagenic effect was observed with 2,3,7,8-tetrachlorodibenzo-p-dioxin in any condition.

Tonsillectomy in Manitoba: who are the patients? the surgeons? the hospitals?

Although tonsillectomy-adenoidectomy rates are declining across North America, this paper suggests they are not falling fast enough. More than half the cases coming to surgery fail to meet accepted standards regardless of who performs the surgery, or where it takes place. Family surgery is still fairly common and is almost never indicated. While younger physicians have higher standards of selection, they are not doing any less T and A surgery than their older colleagues; in fact younger general surgeons are doing more. This study concludes that non-indicated T and A surgery is still a prevalent problem, deserving of widespread attention.

Interrelation of DNA replication, specific growth rate and growth temperature in the sensitivity of Escherichia coli to cold shock

Escherichia coli W3110 was grown in a chemostat under conditions of carbon limitation at various temperatures and specific growth rates (mu). Exponential survivor-time curves following cold osmotic shock were biphasic. These could be described by the sum of two exponential functions representing the survival of sensitive and resistant fractions of the population where the size of the sensitive fraction was directly proportional to mu. Decimal reduction times for the more resistant fraction were unaffected by mu yet decreased with increasing growth temperature. Sensitivity to cold shock was evaluated for an E. coli CR34 mutant, temperature-sensitive in initiation of DNA replication. When grown in the chemostat at the non-restrictive temperature (30 degrees C) sensitivity was directly proportional to mu. Following a rise in the incubation temperature to 42 degrees C, sensitivity decreased markedly and reached a minimum 45 to 60 min after the temperature increase. Sensitivity of the E. coli mutant grown at 30 degrees C and raised to 42 degrees C for 1 h was low and relatively unaffected by growth rate.

Additivity of action between polysorbate 80 and polymyxin B towards spheroplasts of Pseudomonas aeruginosa NCTC 6750

When polymyxin B and polysorbate 80 were used together against spheroplasts of Pseudomonas aeruginosa, the activities were found to be additive. These substances have previously been reported to act synergistically against P. aeruginosa, but little or no intrinsic activity towards intact cells has been attributed to polysorbate 80. We suggest that in addition to enhancing polymyxin B penetration to the cytoplasmic membrane, polysorbate 80 may also act as an antimicrobial agent when polymyxin-induced damage to the outer membrane facilitates the surfactant's passage through the cell envelope.

Influence of suspending media upon the susceptibility of Pseudomonas aeruginosa NCTC 6750 and its spheroplasts to polymyxin B

The lytic and bactericidal actions of polymyxin B on whole cells and spheroplasts of Pseudomonas aeruginosa varied markedly with the suspending media, and there was little correlation between them. Relative rates of lysis of these preparations and also of Bacillus megaterium protoplasts suggested that polymyxin causes progressive damage to the cytoplasmic membrane, such that membrane permeability towards various ions increased as follows: K(+) > Na(+) > NO(3) (-) > Cl(-), Ca(2+), H(2)PO(4) (-)/HPO(4) (2-). Impermeant compounds, such as NaCl and sucrose, protected whole cells against lysis but not against death. It is suggested that lysis of whole cells by polymyxin is a secondary effect, resulting from entry of solutes normally excluded by the cytoplasmic membrane and the fragility of the damaged outer membrane. Because the degree of lysis varies with the external solutes, it should be treated with caution as a descriptor of polymyxin activity.

New design of an ion cyclotron resonance cell capable of temperature variation over the range 80< or =T< or =450 K

The design of an ICR cell capable of convenient operation over the temperature range 80< or =T< or =450 K is reported. Time-temperature plots indicate that the cell can undergo changes in temperatures of DeltaT=100 K in 30-45 min. Thermal gradients in the cell are small, less than +/-2 K. Factors that governed the design of the cell are discussed in detail, as are potential problem areas. The cell is tested by measuring two proton transfer equilibrium constants, one that shows a large temperature coefficient and the other a small temperature coefficient. In each case the results agree well with similar experimental data in the literature.

Effect of R-plasmid RP1 and nutrient depletion on the gross cellular composition of Escherichia coli and its resistance to some uncoupling phenols

The resistance of Escherichia coli batch cultures depleted of carbon (C-dep), magnesium (Mg-dep), or phosphate (P-dep) against low concentrations of 3-chlorophenol, 4-chlorophenol, or 2-phenoxyethanol varied. C-dep cultures were always significantly more sensitive than Mg-dep or P-dep cultures. The presence of R-plasmid RP1 increased the sensitivity of C-dep cultures to 3- and 4-chlorophenol, yet had little effect on those cultured depleted in magnesium or phosphate ions. Cultures with R-plasmid RP1 had increased levels of beta-polyhydroxybutyrate irrespective of the nature of the depleting nutrient. P-dep bacteria had less than one-third of the phospholipid of other cell types, this deficiency being compensated for by increases in fatty acid and neutral lipid content. The reduction in phospholipid content of P-dep cultures was entirely accounted for by decreased diphosphatidylglycerol and phosphatidylethanolamine levels in these cells.

Influence of growth rate and nutrient limitation on the gross cellular composition of Pseudomonas aeruginosa and its resistance to 3- and 4-chlorophenol

Concentrations of 3-chlorophenol and 4-chlorophenol below their minimal inhibitory concentrations were found to increase the permeability of Pseudomonas aeruginosa cells to protons. Levels of such activity were assessed in suspensions of cells prepared from chemostat-grown cultures, limited by either magnesium (Mg-lim) or glucose (G-lim), with the use of five growth rates. Drug concentrations required to produce the same levels of proton translocation varied with the growth rate and the nutrient limiting growth. Fast-growing cultures were more sensitive than slower-growing ones, and G-lim cells were generally more sensitive than Mg-lim ones. 3-Chlorophenol had greater activity than 4-chlorophenol at slow growth rates, but at faster rates of growth their activity was similar. Variation in these iso-effective concentrations for different cells probably reflected an alteration in the ease of drug penetration of the outer envelope. Uptake of the compounds by cells in suspension varied, drug-sensitive bacteria absorbing more than resistant ones. This variation in uptake persisted when bacteria were solvent-extracted to remove readily extractable lipids (REL). Since no significant alteration in cell size was observed among the growth conditions studied, variation in absorption probably resulted from an altered affinity of the cells to the drug, with little involvement of REL. Overall REL content did not alter significantly with growth rate or nutrient limitation. However, total phospholipid content decreased and fatty acid content increased with increasing growth rate. For G-lim and Mg-lim cultures phosphatidylcholine content remained constant, yet phosphatidylethanolamine and phosphatidylglycerol content decreased with increasing growth rate. Diphosphatidylglycerol content decreased with increasing growth rate for Mg-lim cultures and remained relatively constant for G-lim cultures. Lipopolysaccharide content of the cells was higher in Mg-lim than in G-lim cultures and decreased with increasing growth rate in both cases. Lipopolysaccharide content correlated significantly with drug uptake and sensitivity, and it appeared to determine the degree of penetration of the cell envelope by these chlorinated phenols.

Facultative polyploidy in endocrine tissues

Adrenal tissue from 44 autopsies and 30 biopsies of thyroid gland were analyzed by flow--and scanning-cytophotometry. Most nuclei were diploid and the 4C fraction ranged from 1.9 to 6.1% according to the technique, but with no significant difference between controls and adenomas, hyperplasias, adenomatous goiters, or two carcinomas of the thyroid gland. The only significant increase of 4C fraction was found in normal adrenals of patients above 50 years of age (P less than 0,025). Similarly constant was the proportion of 8C nuclei which ranged from 0.5 to 1.3 per thousand. However, in one of 23 adenomatous goiters a total polyploidization was was observed. Comparable results in the literature show that the thyroid gland like the epithelium of seminal vesicles can facultatively become polyploidized, in contrast to the obligatory polyploid orgnas namely the liver and heart. This is not related to malignancy.

Increasing the probability of sterility of medicinal products

Calculations show that official tests for sterility offer unacceptably low degrees of assurance of sterility. Some batches of heat treated articles with 10% contamination can pass the E.P. test on about 92% of occasions. It is proposed that viable counts be made on products immediately before the terminal inactivation procedure and that upper limits be set for the level of contamination. Samples of the product should be inoculated with spores of known resistance characteristics and also with samples of swabs from the production area. Such inoculated products should then be tested for absence of viable organisms, after being subjected to the terminal inactivation procedure. This test should be coupled with close environmental and process control and personnel education. It is recommended that these procedures replace the conventional test for sterility. The use of spores as direct and independent indicators of sterility, especially where the lethal conditions cannot be monitored instrumentally is recommended. A flexible approach is proposed for the use of the ‘lethality factor’ suitable for a terminal heat inactivation procedure; this would depend on the nature of the product and the standard of monitoring facilities and personnel. A change in the language is proposed. A medicinal product processed such that an acceptable probability of sterility exists, should be designated not as sterile but as safe.

Alkaline inorganic pyrophosphatase activity of mammalian-cell alkaline phosphatase

Alkaline phosphatase prepared from mammalian cell cultures was found to have alkaline inorganic pyrophosphatase activity. Both of these activities appear to be associated with a single protein, as demonstrated by: (1) concomitant purification of alkaline phosphatase and alkaline inorganic pyrophosphatase; (2) proportional precipitation of alkaline phosphatase and inorganic pyrophosphatase activities by titrating constant amounts of an enzyme preparation with increasing concentration of antibody; (3) immune electrophoresis, which showed that precipitin bands that have alkaline phosphatase activity also have pyrophosphatase activity; (4) inhibition of pyrophosphatase activity by cysteine, an inhibitor of alkaline phosphatase activity; (5) similar subcellular localization of the two enzyme activities as demonstrated by histochemical methods; (6) hormonal and substrate induction of alkaline phosphatase activity in mammalian cell cultures, which produced a nearly parallel rise in inorganic pyrophosphatase activity.