Amine group of guanine enhances the binding of norfloxacin antibiotics to DNA

The binding mode of norfloxacin, a quinolone antibacterial agent, in the synthetic polynucleotides poly[d(G-C)2], poly[d(I-C)2] and poly[d(A-T)2] was studied using polarized light spectroscopy, fluorescence spectroscopy and melting profiles. The absorption, circular and linear dichroism properties of norfloxacin are essentially the same for all the complexes, and the angle of electric transition dipole moment I and II of norfloxacin relative to the DNA helix axis is measured as 68-75 degrees for all complexes. These similarities indicate that the binding mode of norfloxacin is similar for all the polynucleotides. The decrease in the linear dichroism (LD) magnitude at 260 nm upon binding norfloxacin, which is strongest for the norfloxacin-poly[d(G-C)2] complex, and the identical melting temperature of poly[d(A-T)2] and poly[d(I-C)2] in the presence and absence of norfloxacin rule out the possibility of classic intercalation and minor groove binding. However, the characteristics of the fluorescence emission spectra of norfloxacin bound to poly[d(A-T)2] and to poly[d(I-C)2] are similar but are different to that of norfloxacin bound to poly[d(G-C)2]. As the amine group of the guanine base protrudes to the minor groove, this result strongly suggests that norfloxacin binds in the minor groove of B-form DNA in a nonclassic manner.

The effects of chemical remediation treatments on the extractability and speciation of cadmium and lead in contaminated soils

Two rural soils contaminated by cadmium (Cd) and lead (Pb) were used to evaluate the effect of different chemical treatments on changes in speciation and extractability of Cd and Pb, and in phytoavailability to wheat. Triplicates of seven chemical treatments were tested to compare and evaluate the remediation techniques for contaminated soils using pot experiments. Treatments applied were calcium carbonate, a high quantity of phosphate salt, hog composts, iron oxide, manganese oxide, zeolite, and unamended control. Wheat (Triticum aestivum) was planted in the different amended soils for a further one month to evaluate the effectiveness of treatments on uptake of Cd and Pb by the wheat shoots. Results indicated that addition of calcium carbonate, manganese oxide, or zeolite reduces the extractability of Cd or Pb in both soils, and significantly reduce the uptake of Cd and Pb by wheat shoots. Changes in the extractability and metal sequential fractionations indicate that the exchangeable (or available) form of Cd and Pb in two soils can be transformed into unavailable forms after these amendments.

A small heat shock protein cooperates with heat shock protein 70 systems to reactivate a heat-denatured protein

Small heat shock proteins (sHsps) are a diverse group of heat-induced proteins that are conserved in prokaryotes and eukaryotes and are especially abundant in plants. Recent in vitro data indicate that sHsps act as molecular chaperones to prevent thermal aggregation of proteins by binding non-native intermediates, which can then be refolded in an ATP-dependent fashion by other chaperones. We used heat-denatured firefly luciferase (Luc) bound to pea (Pisum sativum) Hsp18.1 as a model to define the minimum chaperone system required for refolding of a sHsp-bound substrate. Heat-denatured Luc bound to Hsp18.1 was effectively refolded either with Hsc/Hsp70 from diverse eukaryotes plus the DnaJ homologs Hdj1 and Ydj1 (maximum = 97% Luc reactivation with k(ob) = 1.0 x 10(-2)/min), or with prokaryotic Escherichia coli DnaK plus DnaJ and GrpE (100% Luc reactivation, k(ob) = 11.3 x 10(-2)/min). Furthermore, we show that Hsp18.1 is more effective in preventing Luc thermal aggregation than the Hsc70 or DnaK systems, and that Hsp18.1 enhances the yields of refolded Luc even when other chaperones are present during heat inactivation. These findings integrate the aggregation-preventive activity of sHsps with the protein-folding activity of the Hsp70 system and define an in vitro system for further investigation of the mechanism of sHsp action.

Expression and native structure of cytosolic class II small heat-shock proteins

Higher plants synthesize small heat-shock proteins (smHSPs) from five related gene families. The class I and II families encode cytosolic smHSPs. We characterized the class II smHSPs of pea (Pisum sativum) and compared them with class I smHSPs. Antibodies against recombinant HSP17.7, a class II smHSP, recognized four heat-inducible 17- to 18-kD polypeptides and did not cross-react with class I smHSPs. On sucrose gradients the class II smHSPs sedimented primarily at 8 Svedberg units, indicating that they are components of large complexes similar in size to class I smHSP complexes. However, the class I and II complexes were readily distinguishable by nondenaturing polyacrylamide gel electrophoresis and isoelectric focusing. Nondenaturing immune precipitations using anti-HSP17.7 or anti-HSP18.1 (a class I smHSP) antiserum provide further evidence that the class I and II smHSPs exist in different complexes, composed primarily of smHSPs. Recombinant HSP17.7 and HSP18.1 formed complexes of sizes similar to those formed in vivo. When these two smHSPs were mixed, denatured with urea, and then dialyzed, the distinct class I and II complexes again formed, each containing only HSP18.1 or HSP17.7. Thus, cytosolic smHSPs from two related gene families expressed simultaneously form distinct complexes in vivo, suggesting that they have subtly different functions.

A small heat shock protein stably binds heat-denatured model substrates and can maintain a substrate in a folding-competent state

The small heat shock proteins (sHSPs) recently have been reported to have molecular chaperone activity in vitro; however, the mechanism of this activity is poorly defined. We found that HSP18.1, a dodecameric sHSP from pea, prevented the aggregation of malate dehydrogenase (MDH) and glyceraldehyde-3-phosphate dehydrogenase heated to 45 degrees C. Under conditions in which HSP18.1 prevented aggregation of substrates, size-exclusion chromatography and electron microscopy revealed that denatured substrates coated the HSP18.1 dodecamers to form expanded complexes. SDS-PAGE of isolated complexes demonstrated that each HSP18.1 dodecamer can bind the equivalent of 12 MDH monomers, indicating that HSP18.1 has a large capacity for non-native substrates compared with other known molecular chaperones. Photoincorporation of the hydrophobic probe 1,1'-bi(4-anilino)naphthalene-5,5'-disulfonic acid (bis-ANS) into a conserved C-terminal region of HSP18.1 increased reversibly with increasing temperature, but was blocked by prior binding of MDH, suggesting that bis-ANS incorporates proximal to substrate binding regions and that substrate-HSP18.1 interactions are hydrophobic. We also show that heat-denatured firefly luciferase bound to HSP18.1, in contrast to heat-aggregated luciferase, can be reactivated in the presence of rabbit reticulocyte or wheat germ extracts in an ATP-dependent process. These data support a model in which sHSPs prevent protein aggregation and facilitate substrate refolding in conjunction with other molecular chaperones.

Application of contrast agents in the evaluation of stroke: conventional MR and echo-planar MR imaging

The availability of new therapeutic interventions, including neuroprotective agents and endovascular thrombolysis, has given new hope to patients suffering an acute stroke. Early intervention remains a key factor in the effectiveness of these new and traditional treatments. More importantly, the capability to assess the viability and reversibility of the ischemic tissue became essential for better delineation and differentiation of infarcted versus ischemic tissue and patient management. Abnormal MR imaging (MRI) findings during acute stroke usually reflect the underlying pathophysiologic changes, which can be classified into three sequential stages: (a) hypoperfusion, (b) cellular dysfunction and (c) breakdown of the blood-brain barrier. The first stage is a kinetic phenomenon (not biologic) and, therefore, can be detected immediately. Contrast agents accentuate the abnormal flow kinetics and facilitate the early diagnosis of ischemia using either conventional MRI or newly developed echo-planar perfusion imaging (EPPI). The demonstration of abnormal arterial or parenchymal enhancement on conventional MRI during acute stroke provides the earliest sign of vascular occlusion/stenosis. EPPI, in contrast, provides information related to microcirculation (< 100 microns) and tissue reserve (cerebral blood volume) that cannot be obtained by conventional angiography and is directly related to the target end-organ. Further information obtained from both contrast MRI and EPPI may have a predictive value in the clinical outcome of acute stroke patients.

Structure and in vitro molecular chaperone activity of cytosolic small heat shock proteins from pea

Plants synthesize several classes of small heat shock proteins ranging in size from 15 to 30 kDa. Two conserved classes, designated class I and class II, are localized to the cytosol. Recombinant HSP18.1 and HSP17.7, representing class I and class II proteins from pea, respectively, were expressed in Escherichia coli and purified. Non-denaturing polyacrylamide gel electrophoresis and electron microscopy demonstrated that the purified proteins formed discretely sized, high molecular weight complexes. Sedimentation equilibrium analytical ultracentrifugation revealed that the HSP18.1 and HSP17.7 complexes were composed of approximately 12 subunits. Both proteins were able to enhance the refolding of chemically denatured citrate synthase and lactate dehydrogenase at stoichiometric levels in an ATP-independent manner. Furthermore, HSP18.1 and HSP17.7 prevented aggregation of citrate synthase at 45 degrees C and irreversible inactivation of citrate synthase at 38 degrees C. HSP18.1 also suppressed aggregation of lactate dehydrogenase at 55 degrees C. These findings demonstrate that HSP18.1 and HSP17.7 can function as molecular chaperones in vitro.

Consequences of reproduction on the liveweight, fat depth, wool growth, and intake of grazing Merino ewes in the short and long term

Effects of the current and previous year's reproductive performance on liveweight, fat depth, pasture intake, and wool growth were estimated in breeding Merino ewes in each of 2 years and in 4 seasons corresponding with stages of the annual reproductive cycle. Ewes bearing multiple lambs were heavier in early pregnancy (autumn, by 1.5 kg) and in late pregnancy (winter, by 2.5 kg) than single-bearing ewes, with both being heavier than nonpregnant (dry) ewes in winter (by 1.7-4.2 kg). Pregnancy had no effect on fat depth or intake in autumn or winter. Lactating ewes were leaner (by 1.0-1.7 mm), had lower liveweights (by 6.4-8.6 kg), and had substantially higher intakes [by 286-348 g digestible organic matter intake (DOMI)/day] than non-lactating ewes. From summer to winter, ewes that had previously reared a lamb, or lambs, to weaning weighed less, were leaner, and had higher intakes than ewes that were previously dry. Pregnant ewes grew significantly less clean wool and grew it less efficiently (g wool/kg DOMI) in autumn (7-9% less) and winter (11-18% less) than non-pregnant ewes. Similarly, lactating ewes grew less wool (by 23-30%) less efficiently than ewes not suckling, the effect being greater in ewes with multiple lambs. Post-weaning, however, ewes that had reared a lamb to weaning grew significantly more wool (by 6-15%) up to 4 months post-weaning, although efficiency of wool growth was still impaired. The effects of reproductive status on the fibre diameter of wool reflected those for wool growth. Effects of reproduction on productivity are long term and recovery may not be achieved before the next reproductive cycle.

Photophysical properties and photoisomerization processes of Methyl Red embedded in rigid polymer

The photophysical properties of Methyl Red molecules embedded in a poly(methyl methacrylate) (PMMA) matrix were investigated with photoinduced absorption, absorption kinetics, steady-state, and time-resolved luminescence spectroscopy. The excited singlet (S(1)) state lifetimes for trans and cis isomers of Methyl Red in PMMA at room temperature have been measured as 35 and 420 ps, respectively. The excited triplet (T(1)) state energy level and its lifetime at 77 K were also obtained. A slow trans-cis isomerization process having a time constant of a few hundred seconds was observed for the illuminated Methyl Red in rigid polymer. Based on measured photophysical properties and dynamic processes, an energy-level diagram for Methyl Red molecules in rigid polymer is introduced to explain these observations.

Leucine 332 influences the CO2/O2 specificity factor of ribulose-1,5-bisphosphate carboxylase/oxygenase from Anacystis nidulans

The role of Leu 332 in ribulose-1,5-bisphosphate carboxylase/oxygenase from the cyanobacterium Anacystis nidulans was investigated by site-directed mutagenesis. Substitutions of this residue with Met, Ile, Val, Thr, or Ala decreased the CO2/O2 specificity factor by as much as 67% and 96% for the Ile mutant in the presence of Mg2+ and Mn2+, respectively. For the Met, Ile, and Ala mutants in the presence of Mg2+, no loss of oxygenase activity was observed despite the loss of greater than 65% of the carboxylase activity relative to the wild-type enzyme. In the presence of Mn2+, carboxylase activities for mutant enzymes were reduced to approximately the same degree as was observed in the presence of Mg2+, although oxygenase activities were also reduced to similar extents as carboxylase activities. Only minor changes in Km(RuBP) were observed for all mutants in the presence of Mg2+ relative to the wild-type enzyme, indicating that Leu 332 does not function in RuBP binding. These results suggest that in the presence of Mg2+, Leu 332 contributes to the stabilization of the transition state for the carboxylase reaction, and demonstrate that it is possible to affect only one of the activities of this bifunctional enzyme.

A facile method to determine the CO2/O 2 specificity factor for ribulose bisphosphate carboxylase/oxygenase

A rapid method to determine the CO2/O2 specificity factor of ribulose 1,5-bisphosphate carboxylase/oxygenase is presented. The assay measures the amount of CO2 and O2 fixation at varying CO2/O2 ratios to determine the relative rates of each reaction. CO2 fixation is measured by the incorporation of the moles of(14)CO2 into 3-phosphoglycerate, while O2 fixation is determined by subtraction of the moles of CO2 fixed from the moles of RuBP consumed in each reaction. By analyzing the inorganic phosphate specifically hydrolyzed from RuBP under alkaline conditions, the amount of RuBP present before and after catalysis by rubisco can be determined.

Effect of divergent selection for weaning weight on liveweight and wool growth responses to feed intake in Merino ewes

During a 6-week experiment, the feed requirements for maintenance of liveweight (LW) by adult Merino ewes were measured in 2 flocks selected over 32 years for divergent weaning weight. Also examined were the net efficiency of LW gain and wool growth in response to change in feed intake, and the ability to digest dietary organic matter. Ewes selected for high weaning weight (W+) were 31% heavier than those selected for low weaning weight (W-) at the start of the experiment. To maintain LW, W+ ewes ate 24% more digestible organic matter (DOM) per day than W- ewes. There were no differences (P>0.2) in the net efficiency of feed use for LW gain. The W+ ewes digested more (P<0.01) dietary organic matter, by 1.8 percentage units, than W- ewes and, consequently, required only 22% more dry feed to maintain their heavier LW. Ewes from the 2 flocks did not differ (P>0.4) in the amount of wool grown, and as W+ ewes were larger, they produced less (P<0.01) wool per kg LW for the same DOM intake.

The budgetary impact of 5-HT3 receptor antagonists in the management of chemotherapy-induced emesis

The study examined the budgetary implications of using 5-hydroxytryptamine3 receptor antagonists (5-HT3RA), granisetron or ondansetron, in the management of chemotherapy-induced emesis (CIE). A treatment model was constructed to represent a baseline of efficacy and costs for treating a cohort of patients with conventional antiemetics. Groups of patients who would be expected to receive the most benefit from 5-HT3RA were then identified and the effect upon costs of using these compounds in a consecutively larger proportion of selected patients was calculated. On the basis of illustrative costs from The Cookridge Hospital in the UK, it was concluded that the new antiemetics can be used in acute emesis with substantial clinical benefit for an increase of 3-10% to total treatment costs. However, for delayed emesis these compounds have not yet shown a clinical advantage, and the increase in total costs of 12-34% is not justified.

Serine-376 contributes to the binding of substrate by ribulose-bisphosphate carboxylase/oxygenase from Anacystis nidulans

Site-directed mutagenesis was used to change Ser376 in the active site of ribulose-1,5-bisphosphate carboxylase/oxygenase from the cyanobacterium Anacystis nidulans to Cys, Thr, or Ala. When expressed in Escherichia coli and purified, the mutant enzymes exhibited carboxylase activities that were reduced by 99% or more with respect to the activity of the wild-type enzyme. The Km values for ribulose bisphosphate at pH 8.0, 30 degrees C, were elevated from 46 microM for wild-type enzyme to 287, 978, and 81 microM for mutants in which Cys, Thr, or Ala, respectively, replaced Ser376. The Cys and Thr variants were almost devoid of oxygenase activity whereas the Ala variant had 16% as much oxygenase as wild-type enzyme, suggesting that this mutation had greatly elevated the oxygenase:carboxylase ratio.

Direct responses in males and correlated responses for reproduction in females to selection for testicular size adjusted for body weight in young male lambs

Selection based upon testicular diameter adjusted for body weight at 6, 10 and 14 weeks of age was used to produce two lines of sheep, with either high or low testicular size. Ten generations of selection were carried out and the estimate of the realized heritability of the selection criterion was 0.53 +/- 0.01. There were significant positive correlated responses to selection for testicular diameter at 6, 10 and 14 weeks of age, but the correlated responses in body weight at these ages were negative. In mature females, there were significant negative correlated responses to selection in premating body weight in the 1st, 2nd and 3rd breeding season and in the day of the first oestrus in the 2nd breeding season. Litter size per ewe mated had a small positive correlated response to selection in the second breeding season. This latter response appeared to be due to a positive correlated response in fertility, ewes from the High-line having a significantly higher probability of conceiving to a single mating than those from the Low-line. There was no significant correlated response in ovulation rate or litter size per ewe lambing and the genetic correlation between these traits and the selection criterion is likely to be close to zero. This may be due to the adjustment for body weight used, but it is possible that, in any event, body weight in young rams may be a better predictor of female ovulation rate than testicular diameter. These results do not rule out the possibility that testicular size in rams older than those selected would provide a good predictor of genetic merit for female ovulation rate.

Growth and carcass fatness of ewe, wether, ram and cryptorchid crossbred lambs reared at pasture: effects of weaning age

The effects of weaning age and sex on growth, the carcass fatness and dressing percentage were studied in grazing Dorset x (Border Leicester x Merino) lambs. Entire male (ram and cryptorchid) lambs grew significantly (P<0.001) faster from marking to slaughter than did either wethers or ewes. They were also leaner than wethers, which were in turn leaner than ewes (mean � s.e. GR tissue depth: 11.4 � 0.16, 13.9 � 0.22 and 16.3 � 0.23 mm, respectively, at a carcass weight of 19.7 kg). Across all sex groups, the GR measurement increased 1.2 � 0.03 mm per kg increase in carcass weight. An earlier weaning (at 13-15 weeks of age) reduced (P<0.001) liveweight gains. There was also a small reduction (P<0.05) in the GR measurement associated with the earlier weaning, particularly in ewe and wether lambs. The dressing percentage of wethers increased with increasing liveweight over the entire range of weights. However, in ewes and entire males, there was little change in dressing percentage with increasing liveweight above 40 kg. An earlier weaning was associated with a small reduction in dressing percentage.

Pharmacokinetics of norethindrone: effect of particle size

In 24 healthy women between the ages of 19 and 35 years who had not used oral contraceptive preparations for at least 60 days, it was found that the smaller the particle size of norethindrone (NET) administered, the higher was the plasma NET level obtained. Three different preparations having particle sizes of NET smaller than 250 microns, 44 microns or 10 microns were tested in a crossover pattern. The time required to reach maximum plasma concentration (Tmax) became shorter with decreasing particle size, 1.69 hr, 1.52 hr and 1.06 hr, respectively. As particle size was reduced, the maximum NET plasma concentration (Cmax) increased for the 3 different 1 mg NET preparations, i.e. 8.66 ng/ml, 10.53 ng/ml and 15.73 ng/ml. A trial with a 2 mg NET preparation made with NET utilizing the 44 microns same material displayed a Tmax similar to the 1 mg NET preparation having the same particle size while the Cmax reached a level of 17.56 ng/ml. The area under the plasma concentration versus time curve from 0-24 hrs and the extrapolated total area under the curve, increased with decreasing particle size. The use of a smaller particle size allows for more rapid dissolution or oral contraceptive tablets when measured in vitro; however, there is no evidence that such faster dissolution leads to a significant difference in efficacy. Oral contraceptive tablets have, since their inception, utilized both large and small NET particle size material in various preparations.

Bioequivalence of two oral contraceptive drugs containing norethindrone and ethinyl estradiol

Two oral contraceptive drugs, Formulation A and Formulation B, both of similar hormonal content, were compared with each other to determine if they were bioequivalent. Both drugs contain 1 mg of norethindrone (NET) and 0.035 mg of ethinyl estradiol (EE). Application of an interval test for the ratio of the computed parameter means demonstrated equivalence for the two formulations with respect to the 0-24 hour area under the plasma level versus time curve (AUC24), the total area under the curve (AUCtot) and for the maximum plasma concentration (Cmax) for both ethinyl estradiol and norethindrone. The data support the hypothesis for bioequivalence of the two formulations with respect to total absorption.

[The effect of muscle relaxation training on patients with insomnia complaints]

This study was performed to examine the effect of muscle relaxation training on patients with insomnia complaints. The subjects were selected those who have taken poor sleep below 240-300 minutes per day, between 16-15 ages, without organic brain syndromes. Using the Budzinski's muscle relaxation training tapes the patients have been gotten the muscle relaxation training daily during four weeks and examined the state anxiety with Spielberger's Trait-State Anxiety Scale, and investigated Sleep amounts, Blood pressure, Pulse rates, Respiratory rates before and after the muscle relaxation training. The results were as follow: 1. The mean of the State anxiety after the muscle relaxation training (41.8 +/- 6.4) was significantly lower than that of before training (54.2 +/- 7.0) (p less than 0.001). 2. The mean of systolic blood pressure after the training (114.3 +/- 7.8 mmHg) was significantly lower than that of before training (139.0 +/- 9.8) (p less than 0.001). 3. The mean of Pulse rate after the training (89.2 +/- 3.0) was significantly lower than that of before training (103.9 +/- 7.4) (p less than 0.001). 4. The mean of Respiratory rate after the training (18.6 +/- 1.0) was significantly lower than that of before training (22.8 +/- 1.3) (p less than 0.001). 5. The mean of Sleep amount after the muscle relaxation training (459.8 +/- 52.4 minutes) was significantly increased than that of before training (287.3 +/- 30.3) (p less than 0.001).

Study of LH response to GnRH in the young male as a criterion of genetic merit for female reproduction in sheep

A high and a low response line in sheep were selected on the basis of the mean concentration of LH in 10-week-old Finn-Dorset ram lambs after an i.v. injection of 5 micrograms GnRH. After 8 male generations the mean LH response of the high line was more than 5-fold that of the low line and the heritability of the selected trait was estimated at 0.44 +/- 0.015. Highly significant line differences in mean LH response to GnRH were also found in males at 20 weeks of age and females at 10 and 20 weeks of age and the genetic correlations between the four LH response traits appear to be close to unity. Large line differences in the mean FSH response to GnRH were also found in both males and females at 10 and 20 weeks of age. Selection had little effect on the physical characteristics of lambs. High-response line ewes entering their first breeding season at about 7 months of age showed oestrus earlier in the season and had higher ovulation rates and numbers of lambs born per ewe lambing than did low-response line ewes. In the second breeding season, at about 19 months of age, the only line difference was a higher ovulation rate early in the breeding season in high-line ewes. It is suggested that these changes may be mediated by a more rapid response in high-line ewes to increased GnRH stimulation at puberty or at the beginning of the breeding season.

Noninvasive measurement of regional lung water distribution in healthy man and in pulmonary oedema

A quasi steady-state noninvasive, radioisotopic technique for measuring regional lung water distribution in man is described. The method depends upon the dilution principle. 123I labelled human serum albumin (HSA) and sodium iodide (NaI) were injected intravenously, allowed to mix completely within the body fluids and then counted externally over the chest. The size of each compartment to which the markers are confined was calculated from the external count rate and the isotopic concentration of the marker in plasma. 123I-HSA was used to estimate intravascular water and 123I-NaI extracellular water. Ratio analysis of the differential attenuation of the two photoenergies of 123Iodine (29 keV, 159 keV) by the lung and chest wall was used to estimate the absolute amount of isotope in the lung, independent of chest wall contribution, after validation by phantom studies. Regional pulmonary plasma (PPVr) and interstitial (PIVr) fluid volumes in normal subjects were 7.1 +/- 1.4 and 7.6 +/- 1.3 ml.100 cm-3 lung (mean +/- SD; n = 13) at mid-tidal volume, respectively. In patients with the adult respiratory distress syndrome, PPVr and PIVr were 7.0 +/- 2.9 and 15.9 +/- 4.6 ml.100 cm-3 lung (n = 18), respectively. The pulmonary artery wedge (Paw) pressure was normal (12.5 +/- 2.5 mmHg; n = 5). In patients with pulmonary oedema due to left heart disease, PPVr and PIVr were 7.2 +/- 2.7 and 12.1 +/- 3.7 ml.100 cm-3 lung (n = 8), respectively. The mean Paw pressure in this group was high (28.5 +/- 3.9 mmHg).