Quantification of Gordona amarae strains in foaming activated sludge and anaerobic digester systems with oligonucleotide hybridization probes

Previous studies have shown the predominance of mycolic acid-containing filamentous actinomycetes (mycolata) in foam layers in activated sludge systems. Gordona (formerly Nocardia) amarae often is considered the major representative of this group in activated sludge foam. In this study, small-subunit rRNA genes of four G. amarae strains were sequenced, and the resulting sequences were compared to the sequence of G. amarae type strain SE-6. Comparative sequence analysis showed that the five strains used represent two lines of evolutionary descent; group 1 consists of strains NM23 and ASAC1, and group 2 contains strains SE-6, SE-102, and ASF3. The following three oligonucleotide probes were designed: a species-specific probe for G. amarae, a probe specific for group 1, and a probe targeting group 2. The probes were characterized by dissociation temperature and specificity studies, and the species-specific probe was evaluated for use in fluorescent in situ hybridizations. By using the group-specific probes, it was possible to place additional G. amarae isolates in their respective groups. The probes were used along with previously designed probes in membrane hybridizations to determine the abundance of G. amarae, group 1, group 2, bacterial, mycolata, and Gordona rRNAs in samples obtained from foaming activated sludge systems in California, Illinois, and Wisconsin. The target groups were present in significantly greater concentrations in activated sludge foam than in mixed liquor and persisted in anaerobic digesters. Hybridization results indicated that the presence of certain G. amarae strains may be regional or treatment plant specific and that previously uncharacterized G. amarae strains may be present in some systems.     

Occurrence of verocytotoxin-producing Escherichia coli O157 on Dutch dairy farms

During the period from September 1996 through November 1996, 10 Dutch dairy farms were visited to collect fecal samples from all cattle present. The samples were examined for the presence of verocytotoxin (VT)-producing Escherichia coli (VTEC) of serogroup O157 (O157 VTEC) by immunomagnetic separation following selective enrichment. Cattle on 7 of the 10 dairy farms tested positive for O157 VTEC, with the proportion of cattle infected varying from 0.8 to 22.4%. On the seven farms positive for O157 VTEC, the excretion rate was highest in calves ages 4 to 12 months (21.2%). In a follow-up study, two O157 VTEC-positive farms and two O157 VTEC-negative farms identified in the prevalence study were revisited five times at intervals of approximately 3 months. Cattle on each farm tested positive at least once. The proportion of cattle infected varied from 0 to 61.0%. Excretion rates peaked in summer and were lowest in winter. Again, the highest prevalence was observed in calves ages 4 to 12 months (11.8%). O157 VTEC strains were also isolated from fecal samples from horses, ponies, and sheep and from milk filters and stable flies. O157 VTEC isolates were characterized by VT production and type, the presence of the E. coli attaching-and-effacing gene, phage type, and pulsed-field gel electrophoretic genotype. No overlapping strain types were identified among isolates from different farms except one. The predominance of a single type at each sampling suggests that horizontal transmission is an important factor in dissemination of O157 VTEC within a farm. The presence of more than one strain type, both simultaneously and over time, suggests that there was more than one source of O157 VTEC on the farms. Furthermore, this study demonstrated that the O157 VTEC status of a farm cannot be ascertained from a single visit testing a small number of cattle.     

Morphological transformation of C3H/M2 mouse fibroblasts by extracts of human mammary lipid

The aim of this study was to determine whether suckling-induced prolactin (PRL) levels were modified when milk ejection was impaired. Milk ejection impairment was achieved in two experimental models: a) depriving the dam of sleep during suckling and b) increasing the nonsuckling intervals in lactating dams. Sleep deprivation blocked milk ejection and enhanced suckling-induced PRL levels in dams that had been previously separated from their pups. When milk ejection is blocked in litter-deprived dams, mammary glands are not evacuated and they remain engorged. Suckling stimuli were not the cause of the difference in suckling-induced serum PRL levels in control and sleep-deprived dams. The engorgement of the mammary glands may play a role, as a maximum suckling-induced PRL increase was not observed in nonseparated SD dams with nonengorged mammary glands. Moreover, suckling-induced PRL levels were decreased when engorged mammary glands of SD dams were evacuated through an oxytocin injection. A parallel increase between suckling-induced PRL levels and mammary gland weight was observed in the experiments in which milk ejection was impaired through an increase in the intervals of nonsuckling, providing additional support for a relationship between mammary gland engorgement and the regulation of suckling-induced PRL levels.     

Lumbar spine magnetic resonance imaging: comparison between fast spin echo proton density and spin echo T1 axial scans

Spin echo (SE) T1 axial scans are routinely obtained in magnetic resonance imaging of the lumbar spine in many centres. This study directly compared matched SE T1 and fast SE (FSE) proton density (PD) axial scans. Both SE T1 and FSE PD axial scans of the lumbar spine were obtained in 116 consecutive patients. The imaging parameters (field-of-view, slice thickness, interslice gap, number of excitations and matrix size) and scan levels were identical for each pair of sequences. At two selected levels, L4/5 and L5/S1, various structures were independently graded by two observers. In 232 lumbar levels analysed, the bone marrow, epidural fat, disc, extradural nerve root and facet joint were equally well seen on both sequences by both observers (combined mean grades of 2.93-2.99). The thecal sac was marginally better depicted on FSE PD than on SE T1 images, with mean grades of 2.96 and 2.88, respectively. The psoas muscle was adequately visualized for diagnostic purposes on both sequences (mean grades of 2.30-2.32). The cauda equina were better seen on FSE PD (mean grade 1.92) than on SE T1 (mean grade 1.00) images. In conclusion, FSE PD scans are comparable to and may potentially replace SE T1 axial MR scans of the lumbar spine.     

A family of human receptors structurally related to Drosophila Toll

Interhelical electrostatic interactions at specific heptad positions can regulate dimerization specificity of alpha-helical coiled-coils. We have analyzed 20 vertebrate myosin sequences from a variety of organisms and tissues in order to determine if interhelical ionic interactions correlate with the observed myosin dimerization specificity. We find that the sites for potential interhelical ion pairing are identical in virtually all sarcomeric myosins whether they form homo- or heterodimers. We also show that smooth muscle and non-muscle myosin rod sequences exhibit a different conserved pattern of potential interhelical ion pairing. These observations suggest that myosin rod residues involved in interhelical electrostatic interactions do not regulate dimerization specificity, but may contribute to the specific arrangements of myosin molecules that determine differences in the filament morphology of sarcomeric and non-sarcomeric muscles.     

Dystrophia myotonica

The authors present two cases of myotonic dystrophy (Steinert's disease) with cardiac involvement in young adults. They point out the rareness of this disease, the multisystemic involvement and also the diagnostic problems in the absence of the classic clinical picture.     

Pharmacological relaxation of the saphenous vein during harvesting for coronary artery bypass grafting

Spasm of the saphenous vein frequently occurs during harvesting from the leg and high-pressure distension is required to restore an adequate diameter for grafting. Forceful distention has been shown to damage the intima and media and may predispose to subsequent occlusion of the vein graft. Various pharmacologic vasodilators are capable of relaxing veins; in this study, we carried out a systematic investigation to determine the appropriate agents and concentrations for use during vein graft operations. In organ baths, human saphenous vein segments were contracted with potassium or a thromboxane mimetic, and vasodilator agents were then applied. Glyceryl trinitrate, 7.2 micrograms/mL, or papaverine hydrochloride, 11.9 micrograms/mL, caused 80% to 100% relaxation of contraction induced by potassium or thromboxane. Verapamil, 15.5 micrograms/mL, relaxed the potassium contraction by 100% and the thromboxane contraction by 75%. Comparison of the time course of action showed that glyceryl trinitrate had a rapid onset and a short duration of maximal action, whereas verapamil (like papaverine) had delayed onset and a long duration. A mixture of glyceryl trinitrate and verapamil combined rapid onset with long duration of action. We now use a mixture of glyceryl trinitrate and verapamil (pH 7.4) topically and intraluminally during harvesting of the saphenous vein to provide a relaxed conduit for coronary artery bypass grafting.     

Physiological responses to maximal treadmill and handweighted exercise

The purpose of this investigation was to compare the peak physiological responses among four protocols that employed different amounts of handweighted exercise in 16 males (aged 26.3 +/- 4.1 years). The four protocols were (a) uphill treadmill running (UR; 3.36 m.s-1, 2.5% grade increase-3 min-1); (b) uphill treadmill walking while pumping 1.36-kg handweights (HW) (UWHW; 1.79 m.s-1, 5.0% grade increase x 3 min-1; (c) treadmill walking while pumping .91-kg HW (WHW; 1.79 m.s-1, 0% grade, .91-kg HW increase x 3 min-1); and (d) standing in place and pumping HW (SHW; arm work as described in WHW). It was hypothesized that the peak responses would be inversely proportional to the estimated muscle mass activated (i.e., UR = UWHW > WHW > SHW). Dependent variables included peak oxygen uptake (VO2 peak), peak heart rate (HRpeak), peak ventilation (Ve peak), and peak respiratory exchange ratio (RERpeak). No differences were noted between UR and UWHW with respect to any of the dependent variables. All variables (except RERpeak) were greater (p < .01) in UR and UWHW than either WHW or SHW. RERpeak was greater (p < .01) in UR and UWHW than in WHW. VO2 peak and HRpeak were greater (p < .01) in WHW when compared to SHW. Mean VO2 peak was 97.5, 69.7, and 60% of UR for UWHW, WHW, and SHW, respectively. Therefore, walking and pumping handweights provides a maximal stimulus to the oxygen transport system.     

Generating a normalized geometric liver model using warping

This review discusses the development and use of 5-hydroxytryptamine3 (5-HT3) antagonists, especially granisetron, for the treatment of chemotherapy-induced emesis. Following recent evidence suggesting that high-dose chemotherapy is more effective in increasing tumor response rate and median survival time, more effective antiemetic control is essential. Granisetron, a new 5-HT3, is approximately 400 times more potent than metoclopramide and, unlike metoclopramide, does not produce extrapyramidal side effects. Granisetron has been shown to be effective as a single prophylactic dose, over 5 days and in patients receiving repeated cycles of chemotherapy. Patients with nausea and vomiting within the first 24 h after chemotherapy are more likely to experience delayed symptoms; however, episodes of breakthrough nausea and vomiting can be controlled by intervention with one, and in some cases more, doses of granisetron. The development of granisetron represents an important advance in the control of chemotherapy induced emesis.