Detection of bladder carcinoma in females by flow cytometry and cytology

The sensitivity of bladder wash flow cytometry (BWFCM), voided urinary cytology (VUC), and cytology of catheterized urine obtained at the time of cystoscopy (CUC) were reviewed on all women evaluated for bladder cancer at Memorial Sloan-Kettering Cancer Center between June 1985 and December 1986. This comprised sixty-four episodes of pathologically proven bladder cancer in 48 women. Considering positive and suspicious results jointly the sensitivities of BWFCM, CUC and 3 VUC were 75%, 64% and 56%, respectively. If only positive results were considered (i.e., suspicious results considered as negative), the sensitivities of BWFCM, CUC and 3 VUC were 64%, 31% and 32%, respectively. The sensitivities of these tests are less than for a predominantly male population, presumably related to the presence of squamous epithelium and greater frequency of pyuria. However, bladder wash flow cytometry and conventional cytology are still a very valuable addition to cystoscopic examination, and the combination of BWFCM with conventional cytology is more sensitive than either procedure alone.     

Influence of exercise on the fiber composition of skeletal muscle

Summary Biopsy samples from the vastus lateralis muscle (VLM) of man were examined for fiber composition at rest and at selected intervals during prolonged exercise ranging in intensity from 40% to 75% of the total body maximal oxygen uptake (VO _2max) and one-min bouts of exercise at 150%VO _2max. Because of the heterogeneity of fibers in human VLM, studies were also completed where the effect of exercise on the fiber composition of the rat soleus muscle (SM) was examined. In some animals the SM from one hindlimb was removed 9 days prior to their being exercised after which the remaining SM was removed. Exercise reduced muscle glycogen in all experiments. In the studies with man, blood lactate exceeded 17 mmoles/l after the heavy exercise but was largely unchanged by endurance exercise. Colonic temperature of the exercised rats exceeded 40° C. In studies where fibers were identified only as type I and type II, type II fibers in the VLM of all samples (16) taken at rest averaged 61.2±12.5% as compared to 59.0±12.0% after exercise (54 biopsy samples). In a second series of studies with man where the subtypes of type II fibers were identified, there were also no differences in fiber composition of the VLM after varying periods of exercise. Glycogen content and percent fiber composition were the same in right and left SM obtained from rested rats. Exercise (30 to 40 min) did not alter the fiber composition of the rat SM. These data demonstrate that the histochemically demonstratable myofibrillar actomyosin ATPase of skeletal muscle is not altered by a single exercise bout.     

The kinetic mechanism of sheep liver sorbitol dehydrogenase.

The relations between the kinetic parameters for both sorbitol oxidation and fructose reduction by sheep liver sorbitol dehydrogenase show that a Theorell-Chance compulsory order mechanism operates from pH 7.4 to 9.9. This is supported by many parallels with the kinetics of horse liver alcohol dehydrogenase, which operates by this classical mechanism. An isotope-exchange study using D-(2H8)sorbitol confirmed the existence of ternary complexes and that, under maximum velocity conditions, their interconversion is not rate-determining. Substrate inhibition at high concentrations of D-sorbitol or D-fructose confirmed rate-determining enzyme--coenzyme product dissociation, slowed by the existence of more stable abortive ternary enzyme-coenzyme product complexes with substrate. The effect of the inhibitor/activator 2,2,2-tribromoethanol showed the existence of enzyme-NAD-CBr3CH2OH complexes inhibiting the first phase of reaction and enzyme-NADH-CBr3CH2OH complexes dissociating more rapidly than the usual rate-determining enzyme-NADH coenzyme product dissociation in the final phase. Inhibition studies with dithiothreitol also confirmed an ordered binding of coenzymes and second substrates to sorbitol dehydrogenase. Neither D-sorbitol nor D-fructose had any effect on enzyme inactivation by the affinity labelling reagent DL-2-bromo-3-(5-imidazolyl)propionic acid, thus giving no evidence for their existence as binary enzyme-substrate complexes. Several alternative polyol substrates for sorbitol dehydrogenase gave the same maximum velocity as sorbitol. This indicated a common rate-limiting binary enzyme-NADH product dissociation and a similarity of mechanism. An enzyme assay for pH 7.0 and 9.9 is given which enables the concentration of sorbitol dehydrogenase to be determined from initial rate measurements of enzyme activity.     

Hybridization and speciation

Hybridization has many and varied impacts on the process of speciation. Hybridization may slow or reverse differentiation by allowing gene flow and recombination. It may accelerate speciation via adaptive introgression or cause near‐instantaneous speciation by allopolyploidization. It may have multiple effects at different stages and in different spatial contexts within a single speciation event. We offer a perspective on the context and evolutionary significance of hybridization during speciation, highlighting issues of current interest and debate. In secondary contact zones, it is uncertain if barriers to gene flow will be strengthened or broken down due to recombination and gene flow. Theory and empirical evidence suggest the latter is more likely, except within and around strongly selected genomic regions. Hybridization may contribute to speciation through the formation of new hybrid taxa, whereas introgression of a few loci may promote adaptive divergence and so facilitate speciation. Gene regulatory networks, epigenetic effects and the evolution of selfish genetic material in the genome suggest that the Dobzhansky–Muller model of hybrid incompatibilities requires a broader interpretation. Finally, although the incidence of reinforcement remains uncertain, this and other interactions in areas of sympatry may have knock‐on effects on speciation both within and outside regions of hybridization.     

Whole wheat versus mixed layer diet as supplementary feed to layers foraging a sequence of different forage crops

In many cases health and welfare problems are observed in organic egg production systems, as are high environmental risks related to nutrient leaching. These disadvantages might be reduced if the layers are allowed to utilise their ability to forage to a higher degree thereby reducing the import of nutrients into the system and stimulating the hens to perform a natural behaviour. However, very little is known about the ability of modern high-producing layers to take advantage of foraging to cover their nutritional needs, and the aim of the present work was to clarify this subject. Six flocks, each of 26 hens and one cock, were moved regularly in a rotation between different forage crops for a period of 130 days. Half of the flocks were fed typical layer feed for organic layers and half were fed whole wheat. The forage crops consisted of grass/clover, pea/vetch/oats, lupin and quinoa. At the beginning of the experiment, wheat-fed hens had a lower intake of supplementary feed (wheat) and a lower laying rate, egg weight and body weight. However, after a period of 6 to 7 weeks, the intake of wheat increased to approximately 100 g per hen per day and the laying rate increased to the same level as for the hens fed layer feed. For both groups of hens egg weight and body weight increased during the remaining part of the experiment. Crop analysis revealed different food preferences for hens fed layer feed and wheat-fed hens. Wheat-fed hens ate less of the cultivated seeds, whereas the amounts of plant material, oyster shells, insoluble grit stone and soil were larger in the crops from wheat-fed hens. Floor eggs were significantly more frequent in the hens fed layer feed, whereas wheat-fed hens only rarely laid floor eggs. Irrespective of treatment, hens were found to have excellent health and welfare. We conclude that nutrient-restricted, high-producing organic layers are capable of finding and utilising considerable amounts of different feed items from a cultivated foraging area without negative effects on their health and welfare.     

Field evaluation of a semiautomated method for rapid and simple analysis of recreational water microbiological quality

An early warning system using a rapid enzymatic semiautomated method suitable for fecal coliform detection in recreational waters within 8 h was developed further and evaluated in this study. This rapid method was compared to the standard method followed in the United Kingdom. We used 1,011 samples originating from 206 different locations in Wales. When we assessed the presence or absence of fecal coliforms, targeting very low levels of contamination, we obtained 83.9% agreement between the rapid method and the lauryl sulfate broth-membrane filtration technique, whereas direct confirmation of the samples processed by the rapid method showed 89. 3% agreement. Environmental enzymatic background activity was found to be the main limiting factor for this method. Owing to a specific and integrated handling of the results by the software of the instrument, the percentage of false-positive results (a consequence of enzymatic background) was successfully limited to 2.9% by the direct confirmation evaluation. However, 7.8% false-negative results due to "late-growers" had to be accepted in order to produce results within a working day. At present, the method can be used in a more conservative way to assess the environmental threshold of 100 CFU of fecal coliforms per 100 ml in recreational waters. The implications of our findings with regard to the applicability of rapid enzymatic methods are discussed.