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.     

The effect of monensin on gametogenesis and zoosporogenesis in the aquatic fungus,Allomyces macrogynus

Summary Cytoplasmic cleavage in the gametangia and zoosporangia ofA. macrogynus was studied using monensin, an ionophore known to disrupt several endomembrane functions in plant and animal cells. Monensin interfered with normal gamete and zoospore formation in a dose dependent manner such that at a 20 M concentration very abnormal cells were released from the reproductive structures. It was evident that monensin's effect was most pronounced during the first 25 minutes of gametogenesis and parallels in time the onset and continuation of the cytoplasmic cleavage events. Observations using fluorescence and differential interference contrast microscopy indicated that the ionophore inhibited normal cytoplasmic cleavage resulting in the production of multinucleate cells, many of which had either no flagella or multiple flagella. Transmission electron microscopy showed that the monensin-treated gametangia had many large vacuoles which contained amorphous electron-opaque material. X-ray microprobe analysis demonstrated that the elemental composition of the large vacuoles was identical to that of the dense globular inclusions seen in untreated gametangia, and morphological analysis confirmed the relationship between these endomembrane structures. Thus this swollen endomembrane component probably is not involved in the cleavage process. Single endomembrane cisternae which were very common in untreated gametangia were seldom seen in monensin-treated preparations. Instead, many smaller electron-transparent vacuoles were observed. These swollen cisternae may both represent monensin-modified Golgi apparatus equivalents and/or play a critical role during the process of gametogenesis and zoosporogenesis inA. macrogynus.     

Competition between Pseudomonas fluorescens Ag1 and Alcaligenes eutrophus JMP134 (pJP4) during colonization of barley roots

Abstract: To use deliberately released beneficial microorganisms in the rhizosphere, we need a better understanding of the process of root colonization by seed-borne or soil-borne inocula. In this study, we determine the survival of Pseudomonas fluorescens Ag1 and Alcaligenes eutrophus JMP134, their colonization ability as affected by substrates, and the relative importance of migration versus competition for colonization of the root. Ag1 and the 2,4-dichlorophenoxy-acetic acid (2,4-D) degrader JMP134 were inoculated in sterile barley rhizosphere systems. After inoculation of seeds with individual strains, comparable population sizes were established in the rhizosphere as determined by immunofluorescence microscopic total cell counts. Both strains were motile and able to colonize the entire root system without percolating water to stimulate passive transport. Comparing immunofluorescence microscopic cell counts with colony-forming units demonstrated that a subpopulation of A. eutrophus JMP134 closely associated with the root was non-culturable in contrast to the population in rhizosphere soil. Hence, the sole use of culture-dependent methods may give misleading information about the distribution of bacteria in the rhizosphere. Colonization studies with both strains showed that co-inoculation of Ag1 and JMP134 caused a decrease of the population size of JMP134 if 2,4-D was not added to the soil as a specific carbon source for this strain. Thus, competition for limited carbon sources might influence the composition of the bacterial community in the rhizosphere. We also found that the presence of an established inoculum in the soil reduced subsequent root colonization by a seed-inoculated strain, probably by filling available niches, also indicating that competition from other bacteria may be an important factor determining the distribution of seed-borne inocula. This factor may be just as important for the distribution of bacteria as migration.     

Zoosporogenesis in Pseudoperonospora cubensis, the causal agent of cucurbit downy mildew

During sporulation of Pseudoperonospora cubensis on cucumber leaves ( Cucumis saliva ) zoosporangia are formed on the dichotomously branched sporangiophore. The mature zoosporangium has a preformed discharge papilla and the cytoplasm is uncleaved. The zoosporangium wall is decorated and the outer layer of the wall is electron opaque in ultrathin sections. As the zoosporangium is able to survive freezing (- 18°C) for prolonged periods of time (3–4 months) the zoosporangium may serve as the "resting" structure which survives overwintering in Northern latitudes in the absence of oospore formation.
Zoospore cleavage can be synchronized by placing freshly harvested zoosporangia in distilled water. Cleavage of the zoosporangial cytoplasm is by means of the fusion of small vesicles apparently derived from dictyosomes which become highly active after zoosporogenesis is induced.
Vesicles with an osmiophilic electron opaque content are the dominant type of vesicle found in the zoosporangia. The content of these vesicles undergoes dynamic changes during zoosporogenesis and during the late stages of sporogenesis the content becomes finely striated as is typical of these vesicles when observed in the zoospore. On the basis of the results presented here it is suggested that zoosporangium formation and zoosporogenesis in P. cubensis could serve as a model system for assays with obligate oomycetous plant pathogens, also in relation to fungicide mode of action studies.     

Oviposition preference of Anthocoris nemorum and A. nemoralis for apple and pear

Anthocoris nemorum L. and Anthocoris nemoralis Fabricius (Heteroptera: Anthocoridae) are important predators of insect pests in pome fruit. Females insert their eggs in leaf tissue. The females’ choice of oviposition site is important for the subsequent distribution of nymphs on host plants. Oviposition preference for apple and pear leaves was tested in the laboratory in four experiments (experiments 1–4). In three experiments it was tested whether simulated insect damage to leaves (experiments 5 and 6) or the presence of prey (experiment 7) influenced oviposition preference. The effect of the presence of prey was only tested for A. nemorum on apple leaves. There was a highly significant anthocorid species × plant interaction for the number of eggs laid on apple and pear leaves. Anthocoris nemorum laid more eggs on apple than on pear leaves, while A. nemoralis preferred pear. Anthocoris nemorum's preference for apple increased over the 6‐week period in which experiments 1–4 were performed, from 66% to 91% eggs laid on apple leaves. No change over time in preference was found for A. nemoralis. Across experiments 1–4, the majority of A. nemorum eggs were laid near leaf margins, whereas eggs of A. nemoralis were more commonly found in the leaf centre, 5 mm or more from the margin, with a highly significant leaf region × species interaction. There was no significant difference in preference for leaf side between A. nemorum and A. nemoralis, but there was a highly significant plant × leaf side × experiment interaction. Thus, more eggs were laid on the ventral than on the dorsal side of pear leaves in experiment 4, while significantly more eggs were laid on the dorsal side of apple leaves in experiments 3 and 4. Choice tests between damaged and healthy leaves showed that A. nemorum laid significantly more eggs on the damaged leaves, while A. nemoralis preferred healthy leaves. Anthocoris nemorum showed a near‐significant preference for ovipositing on leaves with eggs of Operophtera brumata (Lepidoptera: Geometridae). The oviposition preferences found correspond to the natural distribution of these predators in apple and pear orchards. The preference of A. nemorum for leaf margins, and of A. nemoralis for the leaf centre as an oviposition site, supports earlier observations. A preference for leaf side for oviposition site has not been reported earlier. Preference for damaged leaves could help A. nemorum to locate prey in a field situation.     

Quantitation of chloramphenicol acetyl transferase (CAT) messenger RNA by filter hybridisation using a digoxigenin label

Summary Slot- and dot-blotting are commonly used to evaluate levels of messenger ribonucleic acid (mRNA). Quantitation of bacterially-expressed chloramphenicol acetyl transferase (CAT) mRNA by this method is highly dependent on total RNA immobilised onto the solid support as well as mRNA concentration. mRNA quantitation by comparison with a pure standard results in underestimation. An improved protocol for CAT mRNA detection is described.     

Body composition analysis by DEXA by using dynamically changing samarium filtration

Gotfredsen, Anders, Lene Bæksgaard, and Jannik Hilsted.Body composition analysis by DEXA by using dynamically changing samarium filtration. J. Appl. Physiol.82(4): 1200-1209, 1997.Dual-energy X-ray absorptiometry (DEXA)has a high accuracy for body composition analysis but is influenced bybeam hardening and other error sources in the extremes of measurement.To compensate for beam hardening, the Norland XR-36 introduces adynamically changing samarium filtration system, which depends on thecurrent-absorber thickness. With this system we found a good agreement(r = 0.99) between reference andmeasured amounts of tissue or fat percentages in a plastic phantom andin smaller (~0.5-4 kg) and larger (~5-20 kg) piles oftissue (ox muscle and lard). Scans of six healthy volunteers coveredwith combinations of beef and lard (~5-15 kg) showed a goodagreement (r = 0.99) between referenceand DEXA values of added soft tissue mass and fat percentage. Weconclude that the DEXA method (and, in particular, the Norland XR-36using dynamic filtration) has a high accuracy for body compositionanalysis. It has a potential for gaining status as a reference methodin the future and may presently be used as a supplement to thetraditional methods for body composition analysis.

     

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.