Surgery and anesthesia in Ontario.

Operative and case-fatality rates in Ontario for eight elective (discretionary) and seven nonelective (nondiscretionary) operations and the proportions of these operations and their anesthetic procedures performed by general practitioners were calculated. Cholecystectomy increased in frequency 32% from 1968 through 1973, tonsillectomy and adenoidectomy decreased 37%, and hysterectomy increased 41%. Except for colectomy the rates for nonelective operations changed only slightly over the 6 years. Case-fatality rates (hospital deaths per 10000 operations) for the discretionary operations in 1973 were as follows: extraction of lens, 23.1; tonsillectomy and adenoidectomy, 0.4 (2 deaths among 52938 operations); varicose vein stripping, 6.1; nonrecurrent inguinal herniorrhaphy, 21.9; cholecystectomy, 61.0; hemorrhoidectomy, 9.8; prostatectomy, 115.9; and hysterectomy, 9.6. In 1973 general practitioners did 32% of tonsillectomies and adenoidectomies (61% in 1971), 10 to 20% of inguinal herniorrhaphies, hemorrhoidectomies and appendectomies and 6% or less of the other operations. However, they performed 35% or more of the anesthetic procedures for these four operations as well as for varicose vein stripping, cholecystectomy and hysterectomy. Rates of general-practice surgery and anesthesia in an urban centre in Ontario were substantially less than those for the province as a whole.     

Comparative foraging behavior of Neotropical robber flies (Diptera: Asilidae)

Summary Robber fly species within a Panamanian rain forest comprised distinct shade-seeking (SS) and light-seeking (LS) groups. Thoracic temperatures of LS species averaged 9.2°C greater than ambient, whereas those of SS species averaged only 1.3°C above ambient. Among SS species, attack rate decreased with increasing body mass, whereas relocation rate and attack and relocation distances increased with increasing body mass. Attack and relocation distances of LS species were similar to those of SS species of similar size. Large (>100 mg) LS species, however, had much higher attack and relocation rates than large SS species. The potential costs and benefits of basking are briefly discussed.     

Five-year study of surgical rates in Ontario's counties.

The surgical rates for eight operations (hysterectomy, tonsillectomy/adenoidectomy, cholecystectomy, prostatectomy, appendectomy, mastectomy, colectomy and cesarean section) done in Ontario''s 44 counties from 1973 to 1977 were examined. There was considerable variation among the counties for all the operations studied, although the degree of intercounty variation decreased over the 5 years. Differences in resources (hospital beds and surgeons) explained little of the variation in the rates, but this may be because people crossed county lines for certain operations. Although some counties had consistently high or low rates for individual operations during the 5-year period, only four had consistently high rates for four or more operations, and only five had consistently low rates for four or more. The five counties with teaching health science centres had the highest ratios of specialists and surgeons to population, and, with the exception of one county in 1973, had above-average numbers of hospital beds. Despite the greater resources in these counties, their residents had consistently low rates for cholecystectomy, appendectomy, mastectomy and tonsillectomy/adenoidectomy. However, three of these counties had the highest rates for cesarean section. The variation in the rates is likely due to lack of agreement about indications for surgery or to variation in the use of technology rather than to differences in the incidence or prevalence of disorders.     

Enhanced kinetics of genetically engineered Burkholderia cepacia: the role of vgb in the hypoxic metabolism of 2-CBA

Application of Vitreoscilla hemoglobin (VHb) technology to 2-CBA degradation by Burkholderia cepacia strain DNT under hypoxic conditions was studied in continuous culture chemostats. Dechlorination abilities of both recombinant (VHb gene (vgb) containing) and untransformed cells were investigated at various dilution rates to ensure complete degradation of 2-CBA. As the dilution rate increased from 0.025 to 0.25 h(-1), the ratios of chloride release to degraded 2-CBA concentration decreased from 0.95 to 0.72 and from 0.89 to 0.39 for recombinant and untransformed cells, respectively. A nonstoichiometric relationship between chloride release and 2-CBA degradation was more pronounced for untransformed cells. Recombinant cell densities were 0.1-0.2. g L(-1) greater than untransformed cell densities for a range of dilution rates. As the dilution rate increased, the oxygen uptake rate (OUR) and the substrate utilization rate (SUR) decreased for both strains. The OUR/SUR ratio increased as the dilution rate increased for both strains but was much higher for the recombinant strain compared to untransformed cells. The specific 2-CBA degradation rate of recombinant cells was greater than that of untransformed cells (1.17 vs. 0.46 mg CBA (mg) day(-1), and half-saturation constants for recombinant cells were lower than those of untransformed cells (0.18 and 0.32 mg CBA L(-1), respectively). The pseudo-first-order degradation constants, k(1CBA) and k(1ACE), were higher for recombinant cells (6.5 L (mg cells)(-1) day(-1) and 95.6 L (mg cells)(-1) day(-1), respectively) than those of untransformed cells (1.44 L (mg cells)(-1) day(-1) and 73.7 L (mg cells)(-1) day(-1), respectively).     

Measures of early postoperative mortality: beyond hospital fatality rates.

OBJECTIVE--To quantify the short term risk of postoperative mortality in ways which take account of deaths after discharge and the background risks of death in patients who come to operation. DESIGN--Analysis of linked abstracts of hospital admission records and death certificates for common operations. SETTING--Six health districts in the Oxford region. SUBJECTS--Records of 223,529 operations performed in 1980-6. MAIN OUTCOME MEASURES--In hospital fatality rates, case fatality rates, and standardised mortality ratios at selected time periods during the year after operation and the ratio of early (< 30 days) to late (90-364 days after operation) fatality rates. RESULTS--Fatality rates throughout the year after operations performed after emergency admissions were generally higher than those for similar operations performed after elective admissions and higher than expected from population rates. Examples were prostatectomy, hip arthroplasty, inguinal herniorrhaphy, and cholecystectomy. Common elective operations such as inguinal herniorrhaphy and cataract operations showed no early peak in mortality, but others did. These included transurethral prostatectomy (ratio of early to late mortality 2.0; 95% confidence interval 1.3 to 2.6), hysterectomy (3.2; 1.5 to 6.6), hip arthroplasty (3.8; 2.5 to 5.4), and cholecystectomy (6.9; 4.3 to 11.1). CONCLUSIONS--Temporal profiles of death rates in the year after operation show which operations have early peaks in mortality and which do not. Emergency and elective operations have very different profiles and should be analysed separately. For elective operations for conditions which pose no immediate threat to life the ratio of early to later fatality rates provides a measure of increase in mortality after operation while allowing for the background risk of death in the patient groups.     

Effect of growth rate and substrate limitation on the composition and structure of the cell wall of Saccharomyces cerevisiae

1. A study was made of the composition and structure of walls isolated from yeast grown in continuous culture at different rates, under three conditions of glucose limitation in which the concentrations of glucose and ammonium sulphate in the medium and the oxygen-transfer rate in the culture were varied, and one condition of NH(4) (+) limitation. 2. The contents of total glucan and total mannan in the walls were relatively little affected by the growth rate under any of the four sets of conditions. The phosphorus and protein contents of walls from yeast grown under each of the four conditions increased as the growth rate was decreased. Walls from yeast grown under NH(4) (+) limitation contained only half as much protein as walls from cells grown under glucose limitation. The proportion of lipid was greatest in walls from yeast grown under NH(4) (+) limitation. 3. A procedure was devised for fractionating isolated walls, based on the ease with which the glucan and mannan were extracted with water and with hot and cold 6% (w/v) potassium hydroxide solution. The percentage of glucan, mannan, protein and phosphorus in each of the fractions was affected by the rate of growth and by the nature of the substrate limitation. 4. The beta-fructofuranosidase activities of yeast grown under glucose limitation increased as the growth rate was lowered, but decreased at very low growth rates. The effects at low growth rates were probably due to repression of enzyme synthesis by residual glucose in the culture filtrate. The beta-fructofuranosidase activities of yeast grown under NH(4) (+) limitation were much lower than those from yeast grown under any of the conditions of glucose limitation. 5. Yeast cells grown at any of the rates under NH(4) (+) limitation were longer and thinner than those grown at the same rate under any of the conditions of glucose limitation. Mean cell volumes were dependent on growth rate but not on the nature of the substrate limitation. 6. Electron micrographs of thin sections of isolated walls showed that cells grown under NH(4) (+) limitation had a more porous structure than those from cells grown under any of the conditions of glucose limitation.     

A Comparative Study on Protein Metabolism During Subculture and Differentiation of Tobacco Callus

Comparative study on the subcultured callus of tobacco (Nicotiana tabacum L. cv. Willow leaf) has revealed that protein contents and pr otease activities slowly decreased in the callus during differentiation and bud formation. The synthetic rates of fraction Ⅱ protein (water soluble protein and enzymes) and ribosomal hist one, the levels of total ribosomes, especially the levels of polyribosomes which function the protein synthesis, were higher in the differentiating callus than those in the subcultured callus. This indicates that protein synthesis in differentiating callus is greater than that in non-differentiating callus, and that the protein pattern synthesized in differentiating callus may differ from that in non-differentiating callus. During the late period of culture, the protease activities in subcultured callus rapidly increased, and the levels of polyribosomes, protein synthetic rates and protein contents apparently declined, which may be the result of metabolic changes in callus senescence. Meanwhile in the differentiating callus the protein contents, protein synthesis rates and polyribosome levels although somewhat declined accempanying the growth of formed bud, were still much higher than those in the subcultured callus.     

Elective total hip replacement: incidence,emergency readmission rate,and postoperative mortality.

OBJECTIVES--To report the incidence of elective total hip replacement and postoperative mortality, emergency readmission rates, and the demographic factors associated with these rates in a large defined population. DESIGN--Analysis of linked, routine abstracts of hospital inpatient records and death certificates. SETTING--10 hospitals in six districts in Oxford Regional Health Authority covered by the Oxford record linkage study. SUBJECTS--Records for 11,607 total hip replacements performed electively in 1976-85. MAIN OUTCOME MEASURES--Incidence of operation, postoperative mortality, relative mortality ratios, and incidence of emergency readmission. RESULTS--NHS operation rates increased over time from 43 to 58 operations/100,000 population. Variation in operation rates between districts reduced over time. Operation rates were on average 25% higher in women than men. There were 93 deaths (11/1000 operations) within 90 days of the operation and 208 emergency readmissions (28/1000 operations) within 28 days of discharge. Postoperative mortality and emergency readmission rates increased with age. No significant trend with time was found. Mortality in the 90 days after the operation was 2.5-fold higher (1.9 to 3.0) than in the rest of the first postoperative year. This represented an estimated excess of 6.5 (4.2 to 8.8) early postoperative deaths/1000 operations. Most deaths were ascribed to cardiovascular events. Thromboembolic disease was the commonest reason for emergency readmission. CONCLUSIONS--The pronounced increase in operations in districts with initially low rates suggests a trend towards greater equity in the local provision of NHS hip arthroplasty. The early postoperative clusters of deaths attributed to cardiovascular disease and of readmissions for thromboembolic disease suggest that there is scope for investigating ways of reducing the incidence of major adverse postoperative events.     

Rates of gastric evacuation in piscivorous brown trout, Salmo trutta

SUMMARY. 1. The dry weight of food remaining in the stomachs of piscivorous trout decreased exponentially with time. Gastric evacuation rates increased exponentially with increasing temperature but were unaffected by predator size, meal size or type of fish prey.
2. Mathematical models were developed to estimate both the rate and time for the gastric evacuation of different meal sizes (expressed as dry weight), and were applicable to piscivorous trout of different sizes (length range 10–32 cm) feeding on trout fry or sticklebacks at different temperatures (range 5–18°C).
3. The wet weight of food in the stomachs also decreased exponentially with time, but evacuation rates both increased with temperature and decreased with increasing meal size; the latter relationship occurred because relative rates of water loss from a meal also decreased with increasing meal size. Use of wet or dry weights can therefore lead to different conclusions about the effect of meal size on evacuation rates.
4. When piscivorous trout were fed three consecutive meals of varying size, the models predicted the total dry weight of food left in the stomach, but not the weight remaining for each individual meal. Interactions between meals led to an increase in evacuation rates for meals consumed early in the series and a decrease in evacuation rates for later meals.
5. Evacuation rates for piscivorous trout were compared with those for trout feeding on invertebrates in an earlier study, and were close to those for caddis larvae as prey, higher than those for mealworms and lower than those for a variety of invertebrate prey. Although a great deal is now known about the daily food intake and growth rates of trout feeding on invertebrates, there is little comparable information for piscivorous trout.     

Comparison of surgical and medical management of bleeding peptic ulcers.

During 1975-80, 908 patients admitted to Nottingham hospitals with gastrointestinal bleeding and found to have gastric or duodenal ulcers were analysed retrospectively for short-term outcome of treatment. Overall one-quarter of all patients underwent operation, but when the years 1975-7 were compared with 1978-80 the operation rate fell from one in three to just over one in five. Death rates were much lower in patients treated medically than in those who underwent operation, and the risks of operation were greater for patients with gastric ulcer. Less conventional operations were attended by greater mortality. Almost all patients who died during medical treatment and three-quarters of those who died after operation were over 65. No differences in age or clear variations in haemoglobin concentrations or transfusion requirements were found between the earlier and later periods. Reduction in operation rates had no appreciable effect on mortality, despite the accepted view that early operation is advisable.     

低温条件下黄瓜嫁接株与自根株光合特性的比较

研究了长期低温条件下,设施黄瓜嫁接苗和自根苗(播种后35 d)的净光合速率(P n)、表观量子效率(AQY)、气孔导度(G s)、蒸腾速率(T r)和胞间CO2浓度(C i)与光通量密度(PFD)的关系.结果表明:不同PFD条件下,经过长期低温后黄瓜嫁接苗和自根苗叶片的光饱和点、AQY、P n、G s和T r均较适温条件下显著下降,但嫁接黄瓜下降速度及程度显著低于自根黄瓜.适温条件下,黄瓜C i随PFD增加而降低;低温条件下,嫁接黄瓜C i也随PFD增强而降低,自根黄瓜则始终保持较高水平.以上结果表明,长期低温条件下,黄瓜嫁接苗与黄瓜自根苗均发生气孔抑制现象,但嫁接苗较自根苗保持相对较高的气孔导度,维持较高的光合同化效率,产生较少的过剩激发能,光合器官的伤害程度降低,因而有较强适应低温的能力.     

石山稀有濒危植物在迁地保护后的性状变异

本文对比研究了7种石山稀有濒危植物在石灰岩土壤以及迁移到酸性土壤后的外形特征,生长发育习性及化学元素含量,结果表明,7种石山稀有濒危植物迁移到酸性土壤后发生了以下变化：1）外形变化主要表现为叶片变大变薄,有的植物种子或叶形有变化;2）迁移后开花,结实,落叶期晚1周以上,在气候条件相同的地区,营养生长期没有变化;3）植物体内的化学元素N,Zn,B,Al的含量增加20％以上,而Ca含量减少10％;4）Al的含量虽增加很多,但仍远低于酸性土壤中的植物;Ca的含量虽然减少,但仍高于酸性土壤植物;5）元素K,B的生物吸收系数在石灰岩土壤高于酸性土壤,其他元素N,P,Ca,Mg,Fe,Al,Mn,Zn的生物吸收系数则是酸性土壤高于石灰岩土壤。     

Microcracking damage and the fracture process in relation to strain rate in human cortical bone tensile failure

It is difficult to define the 'physiological' mechanical properties of bone. Traumatic failures in-vivo are more likely to be orders of magnitude faster than the quasistatic tests usually employed in-vitro. We have reported recently [Hansen, U., Zioupos, P., Simpson, R., Currey, J.D., Hynd, D., 2008. The effect of strain rate on the mechanical properties of human cortical bone. Journal of Biomechanical Engineering/Transactions of the ASME 130, 011011-1-8] results from tests on specimens of human femoral cortical bone loaded in tension at strain rates (epsilon ) ranging from low (0.08s(-1)) to high (18s(-1)). Across this strain rate range the modulus of elasticity generally increased, stress at yield and failure and strain at failure decreased for rates higher than 1s(-1), while strain at yield was invariant for most strain rates and only decreased at rates higher than 10s(-1). The results showed that strain rate has a stronger effect on post-yield deformation than on initiation of macroscopic yielding. In general, specimens loaded at high strain rates were brittle, while those loaded at low strain rates were much tougher. Here, a post-test examination of the microcracking damage reveals that microcracking was inversely related to the strain rate. Specimens loaded at low strain rates showed considerable post-yield strain and also much more microcracking. Partial correlation and regression analysis suggested that the development of post-yield strain was a function of the amount of microcracking incurred (the cause), rather than being a direct result of the strain rate (the excitation). Presumably low strain rates allow time for microcracking to develop, which increases the compliance of the specimen, making them tougher. This behaviour confirms a more general rule that the degree to which bone is brittle or tough depends on the amount of microcracking damage it is able to sustain. More importantly, the key to bone toughness is its ability to avoid a ductile-to-brittle transition for as long as possible during the deformation. The key to bone's brittleness, on the other hand, is the strain and damage localisation early on in the process, which leads to low post-yield strains and low-energy absorption to failure.     

Trends in pulmonary embolism death rates for Canada and the United States, 1962-87.

To investigate the effect of advances in the prevention and treatment of pulmonary embolism, we examined the rates of death from pulmonary embolism in Canada for 1965-87 and compared them with those for the United States for 1962-84. The direct method of age standardization was used on sex-specific and age-specific death rates, with the 1960 US population as the standard. In both countries the death rates increased then decreased, although the changes in the Canadian rates occurred later and were less pronounced than those in the US rates. Men and elderly people were at higher risk of death from pulmonary embolism than women and younger people. Prevention strategies, possibly including encouraging a more active lifestyle and targetting high-risk groups, may further reduce pulmonary embolism death rates in both countries.     

Response of Chinese Wampee Axes and Maize Embryos to Dehydration at Different Rates

Survival of wampee (Clausena lansium Sksels) axes and maize (Zea mays L.) embryos decreased with rapid and slow dehydration. Damage of wampee axes by rapid dehydration was much less than by slow dehydration, and that was contrary to maize embryos. The malondialdehyde contents of wampee axes and maize embryos rapidly increased with dehydration, those of wampee axes were lower during rapid dehydration than during slow dehydration, and those of maize embryos were higher during rapid dehydration than during slow dehydration. Activities of superoxide dismutsse (SOD), ascorbate peroxidase (APX) and catalase (CAT) of wampee axes markedly increased during the sady phase of dehydration, and then rapidly decreased, and those of rapidly dehydrated axes were higher than those of slow dehydrated axes when they were dehydrated to low water contents. Activities of SOD and APX of maize embryos notable decreased with dehydration. There were higher SOD activities and lower APX activities of slowly dehydrated maize embryos compared with rapidly dehydrated maize embryos. CAT activities of maize embryos markedly increased during the eady phase of dehydration, and then decreased, and those of slowly dehydrated embryos were higher than those of rapidly dehydrated embryos during the late phase of dehydration.     

Dehydroepiandrosterone and dehydroepiandrosterone sulfate dynamics in obesity.

Dehydroepiandrosterone (D) and dehydroepiandrosterone sulfate (DS) dynamics were studied in three obese female subjects following a single injection of [4-14-CA1D and [7 alpha-3-H]-DS tracers. Dynamic parameters were calculated simultaneously by both the urinary and blood method of compartmentalization; Estimates for the urinary secretion and production rates of D were found to be high, and those of DS varied within normal range. Calculation of the conversion factors, rho DDS and rho DSD, by the urinary method revealed a noraml extraglandular DS yields D conversion, while that for D yields DS appeared deficient in obese female subjects. Estimates of inner and outer pool distribution volumes were extremely increased for free D; in contrast to this, moderately increased inner and decreased outer pool volumes of DS were observed. The metabolic clearance rates of D were normal or decreased and those for DS were greater than normal. The blood production rates of both B and DS were higher in obese female subjects than those estimated for normal women in our previous study; These observations suggest a considerable uptake of unconjugated D by adipose tissue, an overall poor D yields DS conversion and an accelerated DS metabolism in obese female subjects.     

磷饥饿下番茄幼苗根系液泡膜H+-ATPase活性的适应性变化

以‘世纪星’番茄为材料。研究了磷饥饿下番茄幼苗的生长状况及其根部液泡膜H^＋-ATPase活性的适应性变化。结果表明：磷饥饿下番茄幼苗的平均高度均低于对照苗,而主根长度均显著长于对照。磷饥饿提高了番茄幼苗根部液泡膜H^＋-ATPase的水解活性,随着磷胁迫时间的延长,该酶的活性逐渐增大,在磷饥饿7d时达到最大,后又略有降低;而对照番茄幼苗根部该酶的活性变化很小。动力学分析表明：磷饥饿使番茄幼苗根部液泡膜H^＋-ATPase的Km值明显降低,但对该酶的Kmax影响不大。这说明磷饥饿提高了该酶对其底物的亲和力。此外,磷饥饿并不改变液泡膜H^＋-ATPase酶的最适pH值（仍为7．5）。     

Tyr-503 of beta-galactosidase (Escherichia coli) plays an important role in degalactosylation.

Substitutions for Tyr-503 of beta-galactosidase caused large decreases of the activity. Both the galactosylation (k2) and degalactosylation (k3) rates were decreased. Substitutions by residues without transferable protons, caused k3 to decrease much more than k2 while substitutions with residues having transferable protons, caused approximately equal decreases of k2 and k3. Several lines of evidence showed this. The Km values of the substituted enzymes were much smaller than those for the wild type if the substituted amino acid residues did not have transferable protons; this was not the case when the substituted residues had transferable protons. Inhibition studies showed that the Km values were not small because of small Ks values but were small because of relatively small k3 values (compared with the k2 values). The conclusion that the k3 values are small relative to k2 upon substitution with residues without transferable protons is also based upon other studies: studies indicating that the reaction rates were similar with different substrates, studies in the presence of alcohol acceptors, studies showing that the rate of inactivation by 2,4-dinitrophenyl-2-deoxy-2-F-beta-D-galactopyranoside decreased much less than the rate of reactivation; studies on burst kinetics, and pH studies. The data suggest that Tyr-503 may be important for the degalactosylation reaction because of its ability to transfer protons and thereby facilitate cleavage of the transient covalent bond between galactose and Glu-537.     

Anaerobic fluidized bed whey treatment

Anaerobic treatment of moderate strength lactic casein why permeate [2000-7000 mg/L soluble chemical oxygen demand (SCOD)] is possible in fluidized bed reactors. Removal efficiencies up to 90% were obtained at organic removal rates of 7.7 kg SCOD M(-3) day(-1) and efficiencies of 70% were obtained at organic removal rates of 19.5 kg SCOD M(-3) day(-1), both at 35 degrees C. A removal rate of 3.0 kg SCOD M(-3) day(-1) at 50% removal efficiency was obtained at 15 degrees C. Nutrient requirements were much lower than for CSTR systems, and no supplemental nitrogen or phosphorus was required. Removal rates increased and removal efficiency decreased as the organic loading increased. Microorganism concentration increased with decreasing temperature, compensating for reduced reaction rates at lower temperatures.     

Economics of coronary artery bypass grafting.

To decide whether the number of operations for coronary artery bypass grafting should be increased, maintained at the present levels, or decreased we need to know how cost effective they are relative to other claimants on the resources of the National Health Service. For this purpose effectiveness is taken to be the effect on life expectancy adjusted for the quality of life. In an assessment of the cost per quality adjusted life year gained coronary artery bypass grafting rates well for cases of severe angina and extensive coronary artery disease. The cost, however, rises sharply for less severe cases. Bypass grafting seems to compare favourably with valve replacement for aortic stenosis and implantation of pacemakers for heart block; it is distinctly better than heart transplantation and the treatment of end stage renal failure but is probably less cost effective than hip replacement. If the number of operations for coronary artery bypass grafting were to increase it would be a fairly strong claimant only if restricted to the most severe cases. The data on which these judgments are based are crude and in need of refinement. The methodology is powerful, far reaching, and open to comment.