Pasture production in cleared and uncleared grazing systems of central Queensland, Australia

Clearing land of trees and introducing exotic pastures to enhance pasture and cattle production and hence enterprise financial performance are widely practised in Queensland. The results from many previous studies on tree clearing have emphasised the gains in pasture production, but over periods of less than 10–15 years after clearing. The present study questioned the sustainability of pasture production in cleared systems over a longer time-frame (>10 years of clearing). For this, three different age groups of clearing i.e. 5 year, 11–13 year and 33 year were selected in each of 3 major types of tree communities i.e. Eucalyptus populnea, E. melanophloia and Acacia harpophylla in central Queensland. Paired comparisons of cleared and uncleared (intact) pasture systems were selected for each age group of clearing. The results suggest that the initial gains in pasture production upon clearing were compatible with published studies. However, for longer periods of time since clearing, the gains in pasture production were not sustained and were accompanied by risks of land degradation and loss of pasture plant diversity. For E. populnea and A. harpophylla, the maximum benefits from clearing were achieved at 13–15 years whereas for E. melanophloia, any benefits existed only over a short period of 5–6 years. The study emphasises that each tree community exhibits a specific response with regard to the duration of increased pasture production following clearing. To estimate the total benefits from tree clearing in pasture development, it is important to consider both monetary benefits and non-monetary losses from clearing for different types of tree communities.

Evaluation of the anti-proliferative and anti-oxidative activities of leaf extract from in vivo and in vitro raised Ashwagandha

Withania somnifera (Ashwagandha) is used in Indian traditional medicine, Ayurveda and is believed to have a variety of health promoting effects. Molecular mechanisms and pathways underlying these effects have not been studied. We tried to characterize various activities of leaf extract of Ashwagandha (Lash) raised in the field and in the laboratory. We found that the Lash from field-raised plants has a significant anti-proliferative activity in human tumorigenic cells. However, it did not impart any protection against the oxidative damage caused by high glucose and hydrogen peroxide to human tumor cells suggesting that it can be used as an anti-tumor, but not as an anti-oxidant, substance.

Comparison of prognostic factors in patients in phase I trials of cytotoxic drugs vs new noncytotoxic agents

The aims of this study were to identify prognostic variables for toxicity and survival in patients with cancer participating in phase I clinical trials and compare characteristics of those treated with cytotoxic chemotherapy (CT) and non-cytotoxic drugs (non-CT). Data were collected from 420 (114 CT, 306 non-CT) patients enrolled in 16 phase I trials (five CT and 11 non-CT trials) in one cancer centre. Analyses of all patients were used to compare treatment groups, identify predictive variables for toxicity and to estimate prognostic factors in overall survival (OS). These were used to develop a prognostic index (PI). Multivariate analysis found those patients with better performance status, fewer sites of metastases, baseline Hb>12 g dl⁻¹ and WBC or LDH in the normal range had significantly better OS. Male gender, platelet count <450 × 10⁹ l⁻¹, high WBC or treatment with a non-CT phase I agent significantly reduced the chance of grade 3/4 toxicity. Overall survival was not significantly different between the CT and non-CT groups (260 vs 192 days, P=0.47) except for those with liver metastases (228 vs 137 days, P=0.02). Overall tumour response was 4.9% (95% CI: 2.7–7.0%). The PI identified three distinct patient groups with median survival of 321, 257 and 117 days. In conclusion, entry into a phase I trial of a non-CT drug is a safe option for heavily pretreated patients with cancer. The PI generated from these data can estimate the survival probability for patients entering phase I studies.

Antioxidant enzyme gene expression in congestive heart failure following myocardial infarction

Increased oxidative stress and reduction in antioxidant enzymes have been suggested to be involved in the pathophysiology of congestive heart failure subsequent to myocardial infarction (MI). The objective of the present study was to characterize changes in the mRNA abundance and protein levels for the enzymatic antioxidants, superoxide dismutase (SOD), glutathione peroxidase (GSHPx) and catalase during the sequelae of congestive heart failure in rats. MI was produced by the ligation of the left coronary artery and hearts from controls and 1, 4 and 16 week PMI groups were analyzed. Losartan treatment (2 mg/ml in drinking water, daily) was started at 4 weeks and continued for 12 weeks. The mRNA levels for SOD were reduced by about 40% at 1-week PMI, were near to the control levels at 4-week PMI and at 16 weeks PMI, the levels were reduced by about 73% below the controls. GSHPx mRNA levels remained unchanged at all time points. The mRNA levels for catalase remained unchanged at 1 and 4 weeks PMI and were significantly reduced by about 44% at 16 weeks PMI as compared to the controls. The protein levels for MnSOD, CuZnSOD, GSHPx at 1 and 16 weeks remained unchanged in treated and untreated PMI groups. However, the protein levels for catalase was significantly increased in the control and PMI groups treated with Losartan. It is concluded that changes in the SOD and catalase activities during severe heart failure correlated with changes in mRNA for these enzymes. The precise mechanism/s for the improvement in antioxidant reserve and protein levels after Losartan treatment is/are unclear at this time.

Kinetics of antibody response by Dot-ELISA in rabbits immunized with adult Haemonchus contortus antigen

Whole adult soluble extract of Haemonchus contortus as an antigen along with Freund's complete adjuvant, was used to immunize rabbits. Antisera from immunized rabbits were collected at intervals of 30, 60, 90, 120, 150 and 180 days. For the detection and titration of anti-H. contortus antibodies in these sera, Dot-ELISA was developed. Sera collected 30 days post-immunization exhibited a titre of 1:5,000 in all the rabbits except one, where a titre of 20,000 was recorded. Later, all the rabbits attained the highest titre of 40,000 at different periods of post-immunizations, which were maintained 150-180 days. These high titre sera can be of immense use in the identification and characterization of immunodominant antigens of adult H. contortus.

Antimutagenic activities of acetone and methanol fractions of Terminalia arjuna

The antimutagenic effect of benzene, chloroform, acetone and methanol fractions from Terminalia arjuna, a well-known medicinal plant, was determined against Acid Black dye, 2-aminofluorene (2AF) and 4-nitro-o-phenylenediamine (NPD) in TA98 Frameshift mutagen tester strain of Salmonella typhimurium. Among the different fractions, the antimutagenic effect of acetone and methanol fractions was more than that observed with other fractions. Co-incubation and pre-incubation modes of experimentation did not show much difference in the antimutagenic activity of the extracts. Moreover, these fractions inhibited the S9-dependent mutagens, 2AF and Acid Black dye more effectively than the direct-acting mutagens. Studies are under way to isolate and elucidate the nature of the antimutagenic factor in acetone and methanol fractions.

The in vitro antimutagenic activity of Triphala--an Indian herbal drug

A study to evaluate an antimutagenic potential of water, chloroform and acetone extracts of Triphala has been made in an Ames histidine reversion assay using TA98 and TA100 tester strains of Salmonella typhimurium against the direct-acting mutagens, 4-nitro-o-phenylenediamine (NPD) and sodium azide, and the indirect-acting promutagen, 2-aminofluorene (2AF), in the presence of phenobarbitone-induced rat hepatic S9. A combination drug 'Triphala' - a composite mixture of Terminalia bellerica, T. chebula and Emblica officinalis, has been used in traditional system of medicine for the treatment of many malaises, such as heart ailments and hepatic diseases. The drug was sequentially extracted with water, acetone and chloroform at room temperature. The study revealed that water extract was ineffective in reducing the revertants induced by the mutagens. The results with chloroform and acetone extracts showed inhibition of mutagenicity induced by both direct and S9-dependent mutagens. A significant inhibition of 98.7% was observed with acetone extract against the revertants induced by S9-dependent mutagen, 2AF, in co-incubation mode of treatment. Various spectroscopic techniques, namely 1H-NMR, normal 13C-NMR, distortionless enhancement by polarization transfer (DEPT-90 and DEPT-135), UV and IR, are under way to identify the polyphenolic compounds from an acetone extract.

Mechanism of inhibition of the class C beta-lactamase of Enterobacter cloacae P99 by cyclic acyl phosph(on)ates: rescue by return

As previously described (Pratt, R. F.; Hammar, N. J. J. Am. Chem. Soc. 1998, 120, 3004.), 1-hydroxy-4,5-benzo-2,6-dioxaphosphorinone(3)-1-oxide (salicyloyl cyclic phosphate) inactivates the class C beta-lactamase of Enterobacter cloacae P99 in a covalent fashion. The inactivated enzyme slowly reverts to the active form. This paper shows that reactivation involves a recyclization reaction that regenerates salicyloyl cyclic phosphate rather than hydrolysis of the covalent intermediate. The inactivation, therefore, is a slowly reversible covalent modification of the active site. The thermodynamic dissociation constant of the inhibitor from the inactivated enzyme is 0.16 microM. Treatment of the inactivated enzyme with alkali does not produce salicylic acid but does, after subsequent acid hydrolysis, yield one molar equivalent of lysinoalanine. This result proves that salicyloyl cyclic phosphate inactivates the enzyme by (slowly reversible) phosphorylation of the active site serine residue. This result contrasts sharply with the behavior of acyclic acyl phosphates which transiently inactivate the P99 beta-lactamase by acylation (Li, N.; Pratt, R. F. J. Am. Chem. Soc. 1998, 120, 4264.). This chemoselectivity difference is explored by means of molecular modeling. Rather counterintuitively, in view of the relative susceptibility of phosphates and phosphonates to nucleophilic attack at phosphorus, 1-hydroxy-4,5-benzo-2-oxaphosphorinanone(3)-1-oxide, the phosphonate analogue of salicyloyl cyclic phosphate, did not appear to inactivate the P99 beta-lactamase in a time-dependent fashion. It was found, however, to act as a fast reversible inhibitor (K(i) = 10 microM). A closer examination of the kinetics of inhibition revealed that both on and off rates (9.8 x 10(3) s(-1) x M(-1) and 0.098 s(-1), respectively) were much slower than expected for noncovalent binding. This result strongly indicates that the inhibition reaction of the phosphonate also involves phosphylation of the active site. Hence, unlike the situation with bacterial DD-peptidases covalently inactivated by beta-lactams, the P99 beta-lactamase inactivated by the above cyclic acyl phosph(on)ates can be rescued by return. Elimination of the recyclization reaction would lead to more effective inhibitors.

Mechanism of reaction of acyl phosph(on)ates with the beta-lactamase of Enterobacter cloacae P99

A series of acyl phosph(on)ates has been prepared to more closely examine the details of the interactions of this class of molecule with beta-lactamases. In general, they were found to react with the class C beta-lactamase of Enterobacter cloacae P99 in two ways, by acylation and by phosphylation. The acyl-enzymes generated by the former reaction were transiently stable with half-lives of between 3 and 45 s, of comparable lifetime therefore to those generated by the inhibitory beta-lactams cefotaxime, cefuroxime, and cefoxitin. On the other hand, phosphylation led to a completely inactive enzyme. In general, the second-order rate constants for acylation (k(cat)/K(m)) were larger than for phosphylation (k(i)). As expected on chemical grounds, phosphylation was found to be relatively more effective for the phosphonates than the phosphates. The acyl phosphates were much more effective acylating agents however. The acylation reaction was found to be enhanced by hydrophobic substituents in both the acyl and leaving group moieties. Thus, the most reactive compound in this series was benzo[b]thiophene-2-carbonyl 2'-naphthyl phosphate with a K(m) value of 0.15 microM and a k(cat) of 0.2 s(-1); k(cat)/K(m) is therefore 1.3 x 10(6) s(-1) M(-1), making this compound the most specific acyclic acylation reagent for this beta-lactamase yet described. Significant substrate inhibition by this compound suggested that further binding regions may be available for exploitation in inhibitor design. A linear free energy analysis showed that the transition states for acylation of the beta-lactamase by aroyl phosphates are analogues of the corresponding aryl boronic acid adducts. Molecular modeling suggested that the aroyl phosphates react with the P99 beta-lactamase with the aroyl group in the side chain/acyl group site of normal substrates and the phosphate in the leaving group site. In this orientation, the phosphate leaving group interacts strongly with Lys 315.

Glucose-6-phosphate dehydrogenase deficiency in blood donors: screening by micromethaemoglobin reduction test

500 blood donors were screened for G6PD deeiciency using micromethaemoglobin reduction (microMRT) test. Most of the blood donors were young adult males (95.8%). The overall incidence of G6PD deficiency was found to be 0.8%. There, was apparently decreased frequency of G6PD deficient blood donors with increasing age, and no relation could be ascertained between G6PD) deficiency and blood groups.

Peroxisome proliferator activator receptor-gamma agonists and 15-deoxy-Delta(12,14)(12,14)-PGJ(2) induce apoptosis in normal and malignant B-lineage cells

The research described herein evaluates the expression and functional significance of peroxisome proliferator activator receptor-gamma (PPAR-gamma) on B-lineage cells. Normal mouse B cells and a variety of B lymphoma cells reflective of stages of B cell differentiation (e.g., 70Z/3, CH31, WEHI-231, CH12, and J558) express PPAR-gamma mRNA and, by Western blot analysis, the 67-kDa PPAR-gamma protein. 15-Deoxy-Delta(12,14)-PGJ(2) (15d-PGJ(2)), a PPAR-gamma agonist, has a dose-dependent antiproliferative and cytotoxic effect on normal and malignant B cells as shown by [(3)H]thymidine and 3-[4,5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide assays. Only PPAR-gamma agonists (thiazolidinediones), and not PPAR-alpha agonists, mimicked the effect of 15d-PGJ(2) on B-lineage cells, indicating that the mechanism by which 15d-PGJ(2) negatively affects B-lineage cells involves in part PPAR-gamma. The mechanism by which PPAR-gamma agonists induce cytotoxicity is via apoptosis, as shown by annexin V staining and as confirmed by DNA fragmentation detected using the TUNEL assay. Interestingly, addition of PGF(2alpha), which was not known to affect lymphocytes, dramatically attenuated the deleterious effects of PPAR-gamma agonists on B lymphomas. Surprisingly, 15d-PGJ(2) induced a massive increase in nuclear mitogen-activated protein kinase activation, and pretreatment with PGF(2alpha) blunted the mitogen-activated protein kinase activation. This is the first study evaluating PPAR-gamma expression and its significance on B lymphocytes. PPAR-gamma agonists may serve as a counterbalance to the stimulating effects of other PGs, namely PGE(2), which promotes B cell differentiation. Finally, the use of PGs, such as 15d-PGJ(2), and synthetic PPAR-gamma agonists to induce apoptosis in B-lineage cells may lead to the development of novel therapies for fatal B lymphomas.

Effects of dietary selenium (SE) on morphology of testis and cauda epididymis in rats

Selenium is an essential micronutrient for animals. To determine whether its excess in diet induces morphological changes within the male reproductive system, a detailed qualitative and quantitative evaluation of the changes in the histology of the testis and cauda epididymis was undertaken in male rats. Adult male albino rats were fed 6 and 8 ppm Se in diet for 6 and 9 weeks. Each male consuming 6 ppm Se was mated with two untreated females, their offsprings were allowed to mature upto 12 weeks of age. The testes and cauda epididymes of male rats were prepared for light microscopy. Excess of dietary Se caused dose-time-dependent reduction in body weight and reproductive organ weights but increase in number of morphologically abnormal spermatozoa. Histopathological studies of the testes and cauda epididymis have revealed that Se-rich diets cause dose-time-dependent reduction in tubular diameter, epithelial height, number of spermatogenic cells and disintegration of cellular associations in the seminiferous tubules of testes along with reduction in the diameter of cauda epididymal tubules and pseudostratification of their epithelial lining. Progeny (feeding on normal diet) of paternally treated rats has shown retarded growth.

HNE-derived 2-pentylpyrroles are generated during oxidation of LDL, are more prevalent in blood plasma from patients with renal disease or atherosclerosis, and are present in atherosclerotic plaques

Free radical oxidation of human plasma low-density lipoprotein (LDL) produces 2-pentylpyrrole epitopes that are generated by reaction of 4-hydroxy-2-nonenal (HNE), a product of lipid oxidation, with protein lysyl residues. The HNE-derived 2-pentylpyrrole ("HNE-pyrrole") epitopes were detected with an enzyme-linked immunosorbent assay (ELISA) using antibodies (ON-KLH) raised against protein-bound 2-pentylpyrrole obtained by the reaction of 2-oxononanal (ON) with keyhole limpet hemocyanin (KLH). HNE-pyrrole epitopes in human plasma are not associated primarily with LDL protein, apolipoprotein (apo) B, since only 15% of the total HNE-pyrrole immunoreactivity is removed by immunoprecipitation of apo B. The levels of ON-KLH immunoreactivity detected in human plasma were found to be significantly elevated in renal failure and atherosclerosis patients when compared to those in healthy volunteers. HNE-pyrrole immunoreactivity was also detected in atherosclerotic plaques. The highest levels were associated with extracellular connective tissue. Levels of ON-KLH immunoreactivity in human plasma far exceed levels of free HNE, presumably because of the rapid clearance of free relative to protein-bound HNE. Therefore, HNE-pyrrole epitopes provide a more indelible marker of oxidative injury than levels of free HNE.

Isolevuglandin-protein adducts in humans: products of free radical-induced lipid oxidation through the isoprostane pathway

A family of extremely reactive electrophiles, isolevuglandins (isoLGs), is generated in vivo by free radical-induced lipid oxidation and rearrangement of endoperoxide intermediates of the isoprostane pathway. Protein adducts of two different oxidized lipids, isoLGE(2) and iso[4]LGE(2), and the corresponding autoantibodies are present in human blood. Western blot analysis of a polyacrylamide gel electrophoresis gel detects several immunoreactive plasma proteins. Only a minor fraction of the isoLG-protein modifications is associated with low density lipoprotein since mean levels were decreased only 20-22% by immunoprecipitation of apolipoprotein B (apoB). Mean levels of both isoLGE(2) and iso[4]LGE(2)-protein adducts in plasma from patients with atherosclerosis (AS) (n=16) or end-stage renal disease (RD) (n=8) are about twice those in healthy individuals (n=25). These elevated levels are not related to variations in age, total cholesterol or apoB. A linear correlation (r=0.79) between plasma isoLGE(2) and iso[4]LGE(2)-protein adduct levels in all 49 individuals is consistent with a common free radical-induced mechanism for the production of both oxidized lipids in vivo. The correlation is even stronger (r=0.86) for patients with AS or RD. That isoLG-protein adduct levels are more strongly correlated with disease than are total cholesterol or apoB suggests an independent defect that results in an abnormally high level of oxidative injury associated with AS and RD.

Structural and functional consequences of peptide-carbohydrate mimicry. Crystal structure of a carbohydrate-mimicking peptide bound to concanavalin A

The functional consequences of peptide-carbohydrate mimicry were analyzed on the basis of the crystal structure of concanavalin A (ConA) in complex with a carbohydrate-mimicking peptide, DVFYPYPYASGS. The peptide binds to the non-crystallographically related monomers of two independent dimers of ConA in two different modes, in slightly different conformations, demonstrating structural adaptability in ConA-peptide recognition. In one mode, the peptide has maximum interactions with ConA, and in the other, it shows relatively fewer contacts within this site but significant contacts with the symmetry-related subunit. Neither of the peptide binding sites overlaps with the structurally characterized mannose and trimannose binding sites on ConA. Despite this, the functional mimicry between the peptide and carbohydrate ligands was evident. The peptide-inhibited ConA induced T cell proliferation in a dose-dependent manner. The effect of the designed analogs of the peptide on ConA-induced T cell proliferation and their recognition by the antibody response against alpha-d-mannopyranoside indicate a role for aromatic residues in functional mimicry. Although the functional mimicry was observed between the peptide and carbohydrate moieties, the crystal structure of the ConA-peptide complex revealed that the two peptide binding sites are independent of the methyl alpha-d-mannopyranoside binding site.

PPAR-gamma-mediated regulation of normal and malignant B lineage cells

Prostaglandins of the E-series stimulate B lymphocytes by enhancing immunoglobulin-class switching and antibody production. Little is known about whether or not other prostaglandins affect B lineage cells and perhaps counterbalance the stimulatory effects of PGE2. PGD2 is a major product of cyclooxygenase in bone marrow and in macrophages, suggesting a role for this lipid product in immunological responses. PGD2 undergoes dehydration to the biologically active prostaglandin 15-deoxy-delta 12,14-PGJ2 (15d-PGJ2) that binds to the nuclear receptor known as peroxisome proliferator-activated receptor gamma (PPAR-gamma). We found that normal mouse B cells and a variety of B lymphoma cells (e.g., 70Z/3, WEHI-231, CH12, and J558) express PPAR-gamma mRNA and the 67-kDa PPAR-gamma protein. 15d-PGJ2 had a dose-dependent antiproliferative/cytotoxic effect on normal and malignant B cells, as shown by 3H-thymidine and MTT assays. Only PPAR-gamma agonists (i.e., thiazolidinediones) mimicked the effect of 15d-PGJ2 on B lineage cells, indicating that the mechanism by which 15d-PGJ2 negatively affects B lineage cells involves PPAR-gamma. The mechanism whereby PPAR-gamma agonists induced cytotoxicity is via apoptosis, as shown by Annexin V assay. PPAR-gamma agonists may serve as a counterbalance to the stimulating effects of PGE2, which promotes B-cell differentiation. The use of prostaglandins, such as 15d-PGJ2, and synthetic PPAR-gamma agonists to induce apoptosis in B lineage cells may lead to the development of therapies for fatal PGE2-resistant B lymphomas.

Isolevuglandin-protein adducts in oxidized low density lipoprotein and human plasma: a strong connection with cardiovascular disease

Isolevuglandins (isoLGs) are extremely reactive gamma-ketoaldehydes that avidly bind covalently with proteins and cause protein-protein as well as DNA-protein crosslinking. IsoLG-protein adducts are generated upon oxidation of low-density lipoprotein (LDL), and may contribute to atherogenesis since such adducts cause recognition and endocytosis of the modified LDL by macrophage cells. Levels of isoLG-protein adducts in human blood plasma are more closely correlated with disease than are the classical risk factors LDL or total cholesterol. We review the basic research that eventuated in the discovery of isoLGs and describe what is known about their natural occurrence and close connection with cardiovascular disease.

The aryl hydrocarbon receptor interacts with estrogen receptor alpha and orphan receptors COUP-TFI and ERRalpha1

The molecular mechanisms underlying the apparent "cross-talk" between estrogen receptor (ER)- and arylhydrocarbon receptor (AHR)-mediated activities are unknown. To determine how AHR ligand 2, 3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) may inhibit ER action and, conversely, to examine how 17-beta-estradiol (E(2)) affects AHR activity, we examined discrete activities of each receptor, i.e., protein-protein interactions, DNA binding, and transcriptional activation. We report that AHR interacts directly with ERalpha, COUP-TF, and ERRalpha1, in a ligand-specific manner in vitro. Unoccupied or beta-napthoflavone (beta-NF)-occupied AHR showed stronger interaction with ERalpha, COUP-TF, and ERRalpha1 than when AHR was occupied by the partial antagonist alpha-naphthoflavone (alpha-NF), indicating a role for ligand in AHR interaction with these proteins. We also report that AHR interacts with COUP-TF in transfected CV-1 cells. In contrast, the AHR nuclear translocator protein (ARNT) did not interact with COUP-TF, ERRalpha1, or ERalpha. We next examined the interaction of either ERalpha or COUP-TF with a consensus xenobiotic response element (XRE). Purified ERalpha did not bind the consensus XRE, but COUP-TFI bound the consensus XRE, suggesting a role for COUP-TF as a AHR/ARNT competitor for XRE binding. In transiently transfected MCF-7 human breast cancer cells, overexpression of COUP-TFI inhibited TCDD-activated reporter gene activity from the CYP1A1 promoter. TCDD inhibited estradiol (E(2))-activated reporter gene activity from a consensus ERE and from the EREs in the pS2 and Fos genes, and COUP-TFI did not block the antiestrogenic activity of TCDD. The specific interaction of COUP-TF with XREs and AHR together with the inhibition of TCDD-induced gene expression by COUP-TF suggests that COUP-TF may regulate AHR action both by direct DNA binding competition and through protein-protein interactions.

Predicting recovery from acute asthma in an emergency diagnostic and treatment unit

OBJECTIVE

Optimal use of emergency diagnostic and treatment unit (EDTU) resources for treatment of acute asthma should be facilitated by the selection of patients with a high probability of discharge from the EDTU. The study goal was to identify characteristics of the patient or exacerbation that could be used to predict recovery of pulmonary function within 12 hours.

METHODS

Comprehensive cohort design in an urban public hospital. The subjects were 269 patients with moderately severe asthma exacerbations. Data were collected for historical and presenting features and response to treatment over 12 hours. Two outcomes were examined: 1) discharge from the EDTU and 2) achieving 50% predicted peak expiratory flow rate (PEFR) within 12 hours.

RESULTS

The two outcomes showed good concordance. The third-treatment PEFR was found to be predictive of both discharge and reaching 50% predicted PEFR within 12 hours. Since the objective measure of reaching 50% predicted PEFR is more readily defined and thus more generalizable, the authors focused on this outcome when describing prediction zones. Patients with 40% or higher PEFR after third treatment had an 89% probability of reaching 50% predicted in 12 hours, while those with a third-treatment PEFR lower than 32% predicted had only a 22% probability.

CONCLUSIONS

A simple objective measure of pulmonary function early in treatment discriminated among those with high, low, and intermediate probabilities of achieving a specified level of PEFR within 12 hours. Awareness of this probability could assist clinicians attempting to predict discharge from the EDTU and facilitate decision making regarding utilization of EDTU resources.

Microwave absorption in oligomers of ethylene glycol

The dielectric properties of biologically and pharmaceutically important low-molecular weight ethylene glycols H(-OCH2CH2-)n -OH (n = 1,2,4,6) were investigated to clarify the effect of chain length on the dielectric properties. The measurement of dielectric constant and dielectric loss was carried out over the frequency range 200 MHz to 20 GHz at temperatures of 25 degrees C to 55 degrees C. It is found that in these molecules microwave dielectric losses are significant. The dispersion behaviour of these molecules can be represented by Cole-Cole equation. The dielectric properties of these homologous ethylene glycols are discussed in terms of the effects of chain length and intermolecular hydrogen bonds regarding the molecular conformations. These wide frequency range dielectric data have also been discussed in view of the suitable selection of the oligomer of ethylene glycol for cosmetic preparations and other pharmaceutical applications with the intention of protection of the skin from weak microwave radiations present in the surrounding environment. These systematic microwave dielectric data with frequency and temperature variation are not available and are provided in this paper.

Community health centers: unrecognized partners in health professions education

Increasing demand for health professionals with training in ambulatory and primary care practice is placing stress on existing training site capacity. Community health centers can serve as model training sites, offering comprehensive multidisciplinary health care services and teaching clinician role models. In this study, 32 Illinois community and migrant health centers and federally qualified health centers were surveyed to asses their involvement with training in the past three years. Thirty centers had offered training to students from many disciplines, with nursing (27 centers) and medicine (24) the most frequent. Most centers had established formal relationships with training institutions but generally had limited involvement with course planning. Continued participation will likely require adequate funding, with some centers also seeking stronger institutional relationships and better integration of community health issues. Educators and policy makers may need to take a more active role in supporting centers, acquiring funds, and other enabling factors.

Protein adducts of iso[4]levuglandin E2, a product of the isoprostane pathway, in oxidized low density lipoprotein

Levuglandin (LG) E2, a cytotoxic seco prostanoic acid co-generated with prostaglandins by nonenzymatic rearrangements of the cyclooxygenase-derived endoperoxide, prostaglandin H2, avidly binds to proteins. That LGE2-protein adducts can also be generated nonenzymatically is demonstrated by their production during free radical-induced oxidation of low density lipoprotein (LDL). Like oxidized LDL, LGE2-LDL, but not native LDL, undergoes receptor-mediated uptake and impaired processing by macrophage cells. Since radical-induced lipid oxidation produces isomers of prostaglandins, isoprostanes (isoPs), via endoperoxide intermediates, we postulated previously that a similar family of LG isomers, isoLGs, is cogenerated with isoPs. Now iso[4]LGE2-protein epitopes produced by radical-induced oxidation of arachidonic acid in the presence of protein were detected with an enzyme-linked immunosorbent assay. Iso[4]LGE2-protein epitopes are also generated during free radical-induced oxidation of LDL. All of the LGE2 isomers generated upon oxidation of LDL are efficiently sequestered by covalent adduction with LDL-based amino groups. The potent electrophilic reactivity of iso-LGs can be anticipated to have biological consequences beyond their obvious potential as markers for specific arachidonate-derived protein modifications that may be of value for the quantitative assessment of oxidative injury.

Effects of dietary selenium on biochemical composition of rat testis

Treatment of rats with selenium (6 and 8 ppm in diet) for 6 and 9 weeks resulted in decrease in testicular protein, phospholipid content and LDH activity and an increase in the lipid, cholesterol content and activity of ACP and ALP. These alterations have been discussed in relation to interference of selenium in various metabolic processes of testis. It seems that selenium affects the oxido-reductase activity of glutathione and resulting in oxidative damage to testis.

Determination of rifampicin and its main metabolite in plasma and urine in presence of pyrazinamide and isoniazid by HPLC method

A reversed phase HPLC method is described for the simultaneous estimation of rifampicin and its major metabolite desacetyl rifampicin, in the presence of isoniazid and pyrazinamide, in human plasma and urine. The assay involves simple liquid extraction of drug, metabolite and internal standard (rifapentine) from biological specimens and their subsequent separation on a C18 reversed phase column and single wavelength UV detection. In plasma as well as in urine samples, all the three compounds of interest eluted within 17 min. Using methanol-sodium phosphate buffer (pH 5.2; 0.01 M) (65:35, v/v) as mobile phase under isocratic conditions, it was established that isoniazid, pyrazinamide and ascorbic acid (added to prevent oxidative degradation of analytes) did not interfere with the analyte peaks. Recoveries (extraction efficiency) for drug were greater than 90% in both plasma and urine, whereas for metabolite the values were found to be 79 and 86% in plasma and urine, respectively. The plasma and urine methods were precise (total coefficient of variation ranged from 5 to 23%) and accurate (-7 to 5% of the nominal values) for both the analytes. Individual variance components, their estimates and their contribution to the total variance were also determined. Using the same method, unknown samples supplied by WHO were assayed and good correlations were obtained between the found and intended values. The method developed proved to be suitable for simultaneous estimation of rifampicin and desacetyl rifampicin in plasma and urine samples.

Diagnosing ascitic etiology on a biochemical basis

BACKGROUND/AIMS

The analysis of ascitic fluid has been complicated by several new tests. To simplify its assessment, we evaluated ascitic fluid pH with six other parameters prospectively and simultaneously in blood and ascitic fluid in sixty patients with ascites.

METHODOLOGY

Sixty patients were selected on whom abdominal paracentesis was performed in order to determine which tests were the most reliable for the etiological diagnosis of ascites. Their ascitic fluid pH, cholesterol, albumin, and total proteins were analyzed to distinguish between malignant and cirrhotic ascites. The diagnosis of cirrhosis was based on histological findings, and/or clinical, biochemical, and endoscopic/ultrasonographic findings in whom percutaneous liver biopsy was contraindicated.

RESULTS

The serum-ascites albumin gradient was higher (p<0.001) in cirrhotic as compared to tubercular, malignant or cardiac ascites. We discovered that ascitic fluid lactate dehydrogenase and cholesterol were best for diagnosing malignant ascites, ascitic fluid glucose and ascitic fluid/blood glucose ratio were perfect for diagnosing tubercular ascites, and ascitic fluid pH and lactate dehydrogenase were suitable for diagnosing spontaneous bacterial peritonitis. Correspondingly, ascitic fluid albumin, ascitic fluid/serum albumin, total proteins, and serum ascites albumin gradient were best for diagnosing sterile cirrhotic ascites.

CONCLUSIONS

Diagnostic paracentesis is a useful procedure. The practice of ordering a battery of tests on every ascitic fluid specimen should be abandoned. Rather, an algorithm approach should be adopted in which the results of initial analysis guide us to further relent tests that help in arriving at the etiology of ascites.

Knowledge and self-care practices of diabetics in a resettlement colony of Chandigarh

Self-care is an important component of diabetes control programme. A cross-sectional survey was carried out in a resettlement colony of Chandigarh and 60 diabetics aged 20 years and above were identified. Their knowledge and practices regarding diet, genital hygiene, care of foot, wound, complications of diabetes and medication was assessed using a semistructured interview schedule. Most of them (60%) opined that diabetic should consume whatever is cooked in the family. Forty eight diabetics knew that sweets and fatty foods should be avoided but only 18.3% were avoiding them. Genital hygiene was maintained by 51.7% and foot care was done by 63.3% through regular washing. Monitoring of blood sugar was poor (46.7%), only 3 knew and were continuing self testing of urine. Oral anti-diabetic drug compliance rate was 62.9%. None of the patients on insulin injections knew about self therapy. Knowledge regarding diabetic complications was partial. There is a need to reorient and motivate health personnels in educating diabetics about self-care.

NO decreases phosphorylation of focal adhesion proteins via reduction of Ca in rat aortic smooth muscle cells

Our laboratory has previously reported that the antimitogenic effect of nitric oxide (NO) in primary cultures of rat aortic smooth muscle cells may be attributed to activation of protein tyrosine phosphatase and dephosphorylation of protein phosphotyrosine [G.S. Dhaunsi, C. Matthews, K. Kaur, and A. Hassid, Am, J. Physiol. 272 (Heart Circ. Physiol. 41): H1342-H1349, 1997]. The goal of the current study was to investigate the role of cytoplasmic Ca in this process and to identify protein substrates that are dephosphorylated by treatment with NO. Treatment of primary rat aortic smooth muscle cell cultures with the NO donor S-nitroso-N-acetylpenicillamine (SNAP) decreased cytoplasmic Ca levels and elicited phosphotyrosine dephosphorylation. Both effects were mimicked by the extracellular and intracellular Ca chelators ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) and 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA), respectively, and by the Ca channel blocker nifedipine. Conversely, elevation of cytoplasmic Ca via the use of the Ca ionophore A-23187 or high extracellular K+ prevented or attenuated SNAP-induced dephosphorylation. Both BAPTA and nifedipine also decreased DNA synthesis, providing further evidence to link dephosphorylation to antimitogenesis. Two of the proteins dephosphorylated by treatment of cells with NO or EGTA were identified as the focal adhesion proteins, cortactin and paxillin. These results indicate that NO-induced dephosphorylation of protein phosphotyrosine is mediated by reduction of cytoplasmic Ca and suggest that dephosphorylation of focal adhesion proteins may be of relevance to the antimitogenic effect of NO.

Plants obtained from the Khair tree (Acacia catechu Willd.) using mature nodal segments

An in vitro method for obtaining plants of Acacia catechu has been developed using nodal explants from mature `elite' trees growing in the field. Maximum shoot bud development (eight to ten) from a single explant was achieved on Murashige and Skoog (MS) medium supplemented with 6-benzylaminopurine (BAP) (4.0 mg/l) and α-naphthaleneacetic acid (0.5 mg/l). Addition of adenine sulphate (25.0 mg/l), ascorbic acid (20.0 mg/l) and glutamine (150.0 mg/l) to the medium was found beneficial for maximum shoot bud induction. The shoot buds developed into healthy and sturdy shoots on MS medium containing BAP and kinetin at 1.0 mg/l. Excised shoots were rooted on 1/4-strength MS medium with indole-3-acetic acid at 3.0 mg/l and 1.5% sucrose to obtain complete plants.

(Carboxyalkyl)pyrroles in human plasma and oxidized low-density lipoproteins

Free-radical oxidation of human plasma low-density lipoprotein (LDL) produces (carboxyalkyl)pyrrole (CAP) epitopes that were detected with enzyme-linked immunosorbent assays using antibodies raised against keyhole limpet hemocyanin (KLH)-bound 2-(omega-carboxyheptyl)-pyrrole (CHP) and 2-(omega-carboxypropyl)pyrrole (CPP). These antibodies exhibit high structural selectivity (< 0.5% cross-reactivity) in competitive binding inhibition assays with the corresponding human serum albumin (HSA)-bound pyrroles. No cross-reactivity was detected for HSA-bound 2-pentylpyrrole, an epitope that is generated by a reaction of 4-hydroxy-2-nonenal (HNE) with protein lysyl residues. Oxidation of either arachidonic or linoleic acid in the presence of HSA produced an HNE-derived 2-pentylpyrrole epitope. However, only oxidation of linoleic acid formed HSA-bound CHP, while only oxidation of arachidonic acid generated HSA-bound CPP. Since ester hydrolysis with KOH markedly elevated levels of immunoreactive epitopes detected in oxidized LDL, the CAPs are presumably generated by reactions of oxidized cholesteryl esters, triglycerides, and phospholipids with LDL protein, and only some of these oxidized esters are hydrolyzed, e.g., by phospholipase activity associated with LDL. Protein-bound CHP immunoreactivity was detected in human plasma, and levels are significantly elevated in renal failure and atherosclerosis patients compared with healthy volunteers. This provides the first evidence for the biological occurrence of protein-bound CAPs in vivo and further suggests that free-radical oxidation of polyunsaturated lipids produces hydroxyalkenal carboxylate esters whose gamma-hydroxy-alpha,beta-unsaturated aldehyde functionality and reactivity resemble that of HNE.

A comparison between emergency diagnostic and treatment unit and inpatient care in the management of acute asthma

BACKGROUND

Emergency diagnostic and treatment units (EDTUs) may provide an alternative to hospitalization for patients with reversible diseases, such as asthma, who fail to adequately respond to emergency department therapy.

OBJECTIVE

To evaluate the medical and cost-effectiveness, patient satisfaction, and quality of life of patients receiving EDTU care for acute asthma compared with inpatient care.

METHODS

A prospective, randomized clinical trial performed at 2 urban public hospitals enrolled patients with acute asthma (age range, 18-55 years) not meeting discharge criteria after 3 hours of emergency department therapy. Patients were treated with inhaled adrenergic agonists and steroids in an EDTU for up to 9 hours after randomization or with routine therapy in a hospital ward. Patients were followed up for 8 weeks.

MAIN OUTCOME MEASURES

Discharge rate from the EDTU, length of stay, relapse rates, days missed from work or school, days incapacitated during waking hours, symptom-free days and nights, nocturnal awakenings, direct medical costs, patients satisfaction, and patient quality of life.

RESULTS

The study consisted of 222 patients with asthma. Sixty-five patients (59%) treated in an EDTU were discharged home; the remainder were admitted to the hospital. There were no differences during the follow-up period in relapse rates (P = .74) or in any other morbidities between the EDTU and inpatient groups. There were significant differences in the length of stay, patient satisfaction, and quality of life favoring EDTU care. The mean (+/-SD) cost per patient in the EDTU group was $1202.79 +/- $1343.96, compared with $2247.32 +/- $1110.18 for the control group (P < .001).

CONCLUSIONS

Treatment of selected patients with asthma in an EDTU results in the safe discharge of most such patients. This study suggests that quality gains and cost-effective measures can be achieved by the use of such units.

Levuglandin E2-protein adducts in human plasma and vasculature

The prostaglandin endoperoxide PGH2 rearranges nonenzymatically to generate prostaglandins and secoprostanoic acid levulinaldehyde derivatives such as PGE2 and levuglandin (LG) E2, respectively. Direct detection of LGE2 in biological samples is complicated because it is rapidly sequestered by covalent adduction to endogenous nucleophiles including proteins, which produces LGE2-derived protein-bound pyrroles. Therefore, to detect LGE2-protein adducts in vivo, antibodies were raised against a covalent adduct of LGE2 with keyhole limpet hemocyanin (KLH). This antigen enabled the production of high-titer antibodies that exhibit minimal cross-specificity and are sensitive for detecting LGE2-derived pyrroles. Although pyrrole yields are low at LG/protein ratios found in vivo, an enzyme-linked immunosorbent assay with the LGE2-KLH antibodies detects LGE2-derived protein-bound pyrrole immunoreactivity in human plasma from specific patient populations. Furthermore, prominent immunocytochemical staining of human brain thin sections revealed the presence of LGE2-derived pyrrole immunoreactivity, especially in the meningeal vessels of some patients. This demonstration of LG-protein adducts in human plasma and vasculature provides the first evidence for the biological occurrence of levuglandins in vivo and further suggests that these antibodies might prove useful in diagnostic and mechanistic studies of various disease conditions.

A two-year experience of an acute pain service in Singapore

The first anaesthesia-based acute pain service in Singapore is described. The benefits, risks and resource implications of such a service during its first two years are reviewed. One thousand two hundred and sixty-eight (1,268) post-operative patients were treated with either patient-controlled analgesia (310 patients) or epidural opioid analgesia (958 patients). Retrospective analysis of the data revealed good patient satisfaction with a low incidence of potentially life threatening side-effects: more than 79% of patients reported satisfaction with pain control while only 0.2% of patients receiving epidural opioid analgesia experienced clinically significant respiratory depression. There were no reports of respiratory depression in the patient-controlled analgesia group. The authors conclude that the provision of an acute pain service in the local context was safe and resulted in excellent post-operative patient satisfaction.

NO increases protein tyrosine phosphatase activity in smooth muscle cells: relationship to antimitogenesis

We investigated the mechanisms of NO-induced antimitogenesis in primary aortic smooth muscle cells from newborn rats. S-nitroso-N-acetylpenicillamine (SNAP), an NO-releasing agent, decreased basal and growth factor-stimulated DNA synthesis with a threshold effectiveness of 0.3-3 microM. A second NO-releasing agent, 3-morpholinosydnonimine-N-ethylcarbamide, a hydrolysis-resistant cyclic nucleotide, 8-bromo-guanosine 3',5'-cyclic monophosphate (8-BrcGMP), and atrial natriuretic peptides elicited a similar effect, whereas 8-bromo-adenosine 3',5'-cyclic monophosphate (8-BrcAMP) was ineffective, supporting the view that NO and cGMP, but not cAMP, mediated at least some of SNAP's antimitogenic effect. SNAP and 8-BrcGMP decreased the levels of phosphotyrosine, especially in proteins of 70-85 kDa and approximately 215 kDa molecular mass. SNAP decreased protein phosphotyrosine levels with a threshold effectiveness similar to that of its antimitogenic effect. Moreover, SNAP increased protein tyrosine phosphatase (PTPase) activity in cell homogenates, indicating that phosphotyrosine dephosphorylation was likely to be the result of increased PTPase activity. Peroxovanadate, a selective PTPase inhibitor, blocked the antimitogenic effect of 8-BrcGMP, suggesting that loss of protein phosphotyrosine and antimitogenesis were causally linked. These findings describe a potential mechanism for NO-induced antimitogenesis in aortic smooth muscle cells in primary culture.

Serum immunoglobulin estimation in 30 cases of cutaneous vasculitis

Clinically diagnosed and histopathologically proved 30 cases of cutaneous vasculitis (CV) were collected from Dermatovenereology department. Serum immunoglobulins (Igs) estimation was done in all cases. Nineteen cases showed increased levels of Igs, 4 had decreased levels, while in 7 cases Igs levels remained normal. Seventeen had increase in IgG, 17 cases had in IgA and 10 in IgM and decrease in levels of IgM was seen in 3, and IgA in 2 cases. But the fluctuation in levels of Igs was statistically insignificant.

Immunochemical evidence supporting 2-pentylpyrrole formation on proteins exposed to 4-hydroxy-2-nonenal

Previous model studies suggested the formation of lysine-based 2-pentylpyrroles as novel late adduction products formed upon exposure of proteins to the lipid peroxidation product 4-hydroxy-2-nonenal (HNE). Two 2-pentylpyrrole immunogens were prepared, one by treating keyhole limpet hemocyanin (KLH) directly with 4-oxononanal and the other by preformation of 6-(2-pentylpyrrol-1-yl)hexanoic acid from 6-aminocaproic acid and 4-oxononanal, followed by carbodiimide coupling to KLH. Pyrrole content and lysine modification in KLH were assayed independently. Following immunization of rabbits, antibody titer increased and plateaued over a 4 month period. The structural specificity of the IgG fractions of the antisera was evaluated through comprehensive competitive ELISA studies. These antibodies were used to verify the time-dependent appearance of the 2-pentylpyrrole epitope in protein exposed to HNE. Potential advantages of antibodies recognizing "advanced lipid peroxidation end products" over those recognizing "early" HNE adduction products are discussed.