Discriminative stimulus effects of butorphanol: influence of training dose on the substitution patterns produced by Mu, Kappa and Delta opioid agonists

The discriminative stimulus effects of butorphanol were examined in separate groups of pigeons trained to discriminate either a low (0.1 mg/kg), medium (1.0 mg/kg) or high (5.6 mg/kg) dose of butorphanol from saline. The mu-selective opioid antagonist naloxone was considerably more potent than the delta-selective opioid antagonist naltrindole in antagonizing the effects of butorphanol. In each of the training dose groups, the mu opioid agonists morphine, l-methadone and fentanyl, as well as buprenorphine, (-)-pentazocine, nalbuphine, (-)-metazocine and nalorphine, substituted completely for the butorphanol stimulus. The rank order of potency for these compounds in substituting for the butorphanol stimulus was similar across training dose groups and similar to those reported in studies in which fentanyl or morphine were used as training stimuli. (-)-N-allylnormetazocine (NANM) and levallorphan substituted completely for the butorphanol stimulus in the low-dose group, and substituted partially for and antagonized partially the butorphanol stimulus in the medium- and high-dose groups. The kappa opioid agonists spiradoline, bremazocine, U50,488 and U69,593 substituted partially for butorphanol in the low-dose group, an effect that was not reversed by naloxone. In the medium- and high-dose groups, these kappa opioid agonists produced predominantly saline-appropriate responding. The delta opioid agonist BW373U86 substituted completely for butorphanol in the low-dose group, and naltrindole was more potent than naloxone in antagonizing these effects. In the medium- and high-dose groups, BW373U86 substituted partially for the butorphanol stimulus. Unlike the substitution patterns produced by the mu, kappa and delta opioid agonists, the sigma/phencyclidine compounds (+)-cyclazocine and (+)-NANM and the barbiturate pentobarbital produced predominantly saline-appropriate responding in all training dose groups. The present findings suggest that opioids with agonist activity at mu, kappa and delta opioid receptors share similar stimulus effects with a low training dose of butorphanol, whereas only opioids with agonist activity at the mu opioid receptor share stimulus effects with a medium and high training dose of butorphanol.

Asthma presentations to emergency departments in western Sydney during the January 1994 Bushfires

BACKGROUND

From 5 to 12 January 1994, the state of New South Wales suffered from the worst bushfires seen this century. High levels of particulate air pollution were recorded in western Sydney from 7 to 14 January 1994, with nephelometry readings reaching 10.24 beta scat (10(-4)/m) and particulate matter < 10 mu readings peaking at 250.00 micrograms/m3. The aim of this study was to determine whether there was an increase in the proportion of asthma presentations to emergency departments (ED) in western Sydney as a result of the bushfire-generated particulate air pollution.

METHOD

We retrospectively analysed the emergency room attendance books for asthma presentations from seven public hospitals serving the Western Sydney and Wentworth Health Areas over two 6-7 week periods, 17 December 1992 to 31 January 1993, and 17 December 1993 to 31 January 1994. Air pollution and meteorological data were obtained from local monitoring stations.

RESULTS

The difference in the proportion of all ED presentations that were due to asthma during the week of the bushfire-generated air pollution, compared with the same week 12 months before, after adjusting for baseline changes over the 12-month period, was 0.0067 (95% CI: -0.0007, 0.0141). The maximum daily nephelometry reading was not a significant predictor of the daily number of asthma presentations to ED in any of the Poisson regression models.

CONCLUSIONS

The bushfire-generated particulate air pollution in January 1994 did not result in an increase in asthma presentations to ED in western Sydney.

Haemopoietic growth factors, the cell cycle of acute myeloblastic leukaemia progenitors and sensitivity to cytosine arabinoside

We describe an 'in vitro' model which permits assessment of acute myeloblastic leukaemia (AML) progenitor cells' response to Ara-C alone and in conjunction with recombinant human (rh) cytokines by evaluating cell cycle characteristics of purified AML blast progenitors and their chemosensitivity in clonogenic culture before and after cytokine priming. Parallel investigation of Ara-C/cytokine treatment on normal CFU-GM progenitors was included as these cells are important for post-therapeutic reconstitution of haemopoiesis. Kinetic and clonogenic findings for AML marrows were extremely variable with G+GM-CSF or IL-3 priming. However, inclusion of rhSCF and resultant synergism with the other cytokines, introduced a pronounced element of consistency in AML results. Normal CFU-GM responded to rhG+GM-CSF or IL-3 with increased kinetic activity and sensitivity to Ara-C. rhSCF synergised strongly with the other factors, causing increased cell cycling and attainment of maximal chemosensitivity 'in vitro'. No correlation was evident between 'in vitro' findings for AML samples, patient FAB types or clinical outcome. This study highlights the fact that both normal and AML cells can be targeted by rh cytokines, particularly when rhSCF is included in priming cocktails.

Stress-induced changes in brain-derived neurotrophic factor expression are attenuated in aged Fischer 344/N rats

Aging and stress can sometimes result in a decline in brain function. We addressed the question whether changes in the expression of neurotrophic factors, which are necessary for the survival and maintenance of neurons, might occur during aging and stress. Therefore, we used in situ hybridization to investigate the effects of aging and stress on neurotrophic factor expression in young (3-4 month) and old (24 month) male Fischer 344/N rats. The ability of acute immobilization stress (2 h) to modulate BDNF mRNA levels in old rats was significantly reduced both in the hippocampus (a smaller decrease in BDNF) and the PVN (a smaller increase in BDNF) compared to young rats. In contrast, the induction of nerve growth factor and neurotrophin 3 (NT-3) by stress was not influenced by age. The diminished BDNF responses to stress in aged rats may be relevant to difficulties in adaptation to stress encountered during old age.

The effect of ketoprofen creams on periodontal disease in rhesus monkeys

Ketoprofen creams were evaluated for the treatment of periodontal disease in a placebo-controlled, double-blind study in the rhesus monkeys, Macaca mulatta. Two formulations containing ketoprofen (1%), with or without vitamin E, were evaluated against appropriate controls (8 monkeys per group). Two weeks prior to treatment, the animals received prophylaxis on only the left side of the mouth (spontaneous model). Selected teeth on the right side of the mouth were ligated (ligature model). The creams were administered to the gingiva once daily at a standard dose of 1.8 ml per monkey for 6 months. Clinical assessments were made 2 wk before initiation, at baseline and 1, 2, 3 and 6 months post-treatment. The clinical parameters included plaque formation, gingival redness, edema, bleeding on probing and Ramfjord Attachment Level measurements (RAL). Radiographs were taken at 2 wk before initiation, baseline and at 3 and 6 months post-treatment. Digital, subtraction radiography was used to measure vertical linear bone loss along the interproximal root surfaces of the left and right mandibular first molars. Gingival crevicular fluid (GCF) was collected for biochemical assays on PGE2, TxB2, LTB4, IL-1 beta and TNF alpha. There were no significant differences among groups with respect to gingival indices. Radiographic data demonstrated significant positive effects on bone activity in both groups treated with ketoprofen formulations with improvement over time in the ligature model (0.01 < or = p < or = 0.04). The placebo group exhibited bone loss of 1.96 +/- 0.48 and 1.40 +/- 0.56 mm per site at 3 and 6 months, respectively. The group treated with ketoprofen cream showed an apparent bone gain of 0.28 +/- 0.41 and 0.78 +/- 0.47 mm per site at 3 and 6 months, respectively. The group treated with ketoprofen cream containing vitamin E showed a mean bone loss of 0.41-0.48 mm per site at 3 months with improvement to an apparent bone gain of 0.31 +/- 0.44 mm per site at 6 months. The biochemical data demonstrated early and significant suppression of GCF-LTB4 by both ketoprofen formulations at 1 month, which preceded the significant suppression of GCF-PGE2 at 2 and 3 months in the ligature model (p < 0.003) and at 2 to 6 months in the spontaneous model (p < 0.02). We conclude that ketoprofen at 1% level in suitable topical vehicles can effectively inhibit GCF-LTB4 and GCF-PGE2 and positively alter alveolar bone activity in the ligature-induced model of periodontitis in the monkey.

Glycoxidation and oxidative stress in Parkinson disease and diffuse Lewy body disease

Oxidative stress is well accepted as an important pathogenic factor in Parkinson disease, based largely on indirect evidence. Recently, we have developed antibodies that recognize specific advanced glycation end-products (anti-pentosidine and anti-pyrraline), protein modifications that are potentiated by oxidative stress in a process termed glycoxidation. We applied these antibodies immunocytochemically to affected regions in Parkinson disease and diffuse Lewy body disease brains. Additionally, we used antibodies to heme oxygenase-1, a putative marker of oxidative stress response. Immunoreactivity to pentosidine, pyrraline, and heme oxygenase-1 was seen in the substantia nigra of Parkinson disease and the neocortex of diffuse Lewy body disease. Heme oxygenase-1 was further demonstrated by immunoelectron microscopy in intimate association with filaments of cortical Lewy bodies. Immunolocalization of advanced glycation end-products and a marker of oxidative stress response induction provides evidence that glycoxidation and oxidative stress may be an important pathogenic factor in diseases characterized by Lewy body formation, and furthers the evidence that cytoskeletal proteins and their inclusions are susceptible to oxidative stress.

Segmental bioelectrical impedance in patients with chronic renal failure

We studied changes in hydration by whole body and segmental (arm, leg and trunk)bioelectrical impedance analysis (BIN in patients with chronic renal failure (CRF) undergoing haemodialysis and continuous ambulatory peritoneal dialysis (CAPD). Mean (SD) fluid removal by haemodialysis of 1.38 (0.81) kg was overestimated by whole body BIA at 1.83 (1.13) I, P < 0.005. Peritoneal fluid drained from the CAPD patients of 1.88 (0.36) kg was underestimated by whole body BIA at 0.59 (0.35) I, P < 0.0001. Resistance and reactance significantly increased for the whole body and all segments (except trunk reactance) after haemodialysis. Drainage of CAPD fluid resulted in smaller increases in trunk resistance and whole body resistance. The increase in trunk resistance was less in CAPD than haemodialysis patients, even though the volume of fluid drained from the peritoneum in CAPD patients exceeded that removed from the whole body during haemodialysis. We conclude that whole body BIA does not estimate changes in body fluid with sufficient accuracy to be of use in clinical practice. Segmental impedance may be a potentially useful method for investigation of regional changes in body fluid, though is insensitive to changes within the peritoneal cavity.

The novel cardioprotective agent BMS-180448 activates a potassium conductance in cardiac and vascular smooth muscle

The goal of the present study was to further characterize the effects of the novel cardioprotective agent BMS-180448 on potassium fluxes in cardiac and vascular smooth muscle. Exposure of voltage-clamped guinea pig ventricular myocytes to BMS-180448 (300 microM) produced an inhibition of IK followed by the delayed (5.5 +/- 0.5 min) activation of a large time-independent potassium current. At 100 microM, BMS-180448 produced only inhibition of IK. The BMS-180448 activated current was refractory to block by 30 microM glyburide but was largely inhibited by 100 microM alinidine (84 +/- 6% inhibition at +40 mV). Cromakalim (100 microM)-activated currents were fully inhibited by 3 microM glyburide and 79 +/- 4% blocked by 100 microM alinidine. The current responses to BMS-180448 were unaffected by the inclusion of 10 mM UDP (100 microM ATP) in the pipette. BMS-180448 also produced a concentration-dependent increase in 86Rb efflux from aortic strips; efflux responses were increased in low calcium medium and fully antagonized by 3 microM glyburide. Thus, BMS-180448 activates a potassium conductance in both cardiac and smooth muscle. The glyburide sensitivity of the BMS-180448-induced increase in 86Rb efflux from the aortic preparations suggests that this drug activates IKATP in vascular smooth muscle. Moreover, the observation that BMS-180448 (100 microM) partially inhibits the effects of cromakalim in ventricular muscle cells suggests that these drugs interact, directly or indirectly, with a common site in cardiac muscle.

Measurement of total body water by bioelectrical impedance in chronic renal failure

OBJECTIVE

Abnormalities of body hydration are common in patients with advanced chronic renal failure (CRF) and may be associated with important adverse clinical effects, even in the absence of clinical features of fluid retention or depletion. Bioelectrical impedance analysis (BIA) is a simple, non-invasive method of measuring body water content and thus could be of use in the management and study of patients with CRF. This study was performed to assess the ability of BIA to measure total body water (TBW) in patients with CRF.

DESIGN

TBW was measured by two different impedance systems, with comparison of the results with TBW determined by deuterium oxide dilution (D2O).

SETTING

Renal Unit, Leeds General Infirmary and Centre for Bone and Body Composition Research, University of Leeds, UK.

RESULTS

The range of the 95% limits of method agreement between BIA and D2O expressed as a percentage of the mean for the group was +/- 13.4% for the RJL 101A system and +/- 15.6% for the Holtain system in controls. For the whole CRF group the limits were moderately greater than controls at +/- 17.3% (RJL) and +/- 21.9% (Holtain). Analysis of subgroups of the CRF patients showed the smallest limits in those receiving peritoneal dialysis (+/- 15.5% RJL and 18.2% Holtain). Limits were greater for patients on haemodialysis (+/- 16.0% RJL and +/- 23.8% Holtain) and undialysed patients (+/- 20.1% and +/- 23.0%).

CONCLUSIONS

BIA is less accurate for the measurement of TBW in patients with CRF than in healthy subjects, though in some groups of patients the effect of CRF on the validity of this technique may be only mild. Abnormalities of reactance suggest that abnormal variability in the distribution of fluid between intra- and extracellular compartments is the major cause of reduced accuracy of TBW calculated by BIA in CRF patients.

The use of poetry to test nursing knowledge

The traditional testing process often is static and intimidating to students and encourages multiple guessing or rote recall of information. To avoid these problems and encourage student creativity and critical thinking, the author developed a test that solely uses poetry. In this article, she discusses the use of poetry to test nursing knowledge.

Whole body and regional body composition in patients with chronic renal failure

BACKGROUND

Nutritional state is a powerful prognostic factor in chronic renal failure (CRF). Techniques for the assessment of nutrition have limitations which are often most marked in the presence of renal disease. We have used techniques of body composition analysis to assess the nutritional state of groups of patients with CRF.

METHODS

Body composition was measured in groups of patients with advanced CRF on conservative treatment, peritoneal dialysis, and haemodialysis and the results compared with a healthy control group. The selection criteria for the CRF patients ensured that they were "stable' with no recent intercurrent illness, and dialysis adequacy was satisfactory according to currently accepted targets.

RESULTS

Whole body dual energy X-ray absorptiometry (DEXA) found significant reduction in lean tissue in haemodialysis patients and female peritoneal dialysis patients. Regional analysis with DEXA showed reduction in limb (especially arm), lean tissue in CRF patients, with arm lean tissue being reduced in all three CRF groups for females and both dialysis groups for males. Limb/trunk lean tissue ratios were significantly reduced for all CRF groups. Bioelectrical impedance showed reductions of fat-free mass in the same groups who had reduced whole body lean tissue with DEXA, but skinfold anthropometry failed to detect any significant reduction in fat-free mass.

CONCLUSIONS

We conclude that even in "healthy' groups of CRF patients receiving adequate dialytic and dietary management, lean tissue depletion is a common problem. Regional analysis by DEXA, with measurement of limb lean tissue mass is a more sensitive method for the detection of lean tissue depletion than measurement of whole body lean tissue in patients with CRF.

Influence of changes in peritoneal fluid on body-composition measurements by dual-energy X-ray absorptiometry in patients receiving continuous ambulatory peritoneal dialysis

The effect of the presence of intraabdominal fluid on measurement of body composition by dual-energy X-ray absorptiometry (DXA) was determined by scanning 14 patients who were receiving continuous ambulatory peritoneal dialysis (CAPD) before and after the drainage of peritoneal dialysate, resulting in a mean (+/- SD) weight loss of 1.81 +/- 0.34 kg. DXA showed changes in whole-body soft tissue, which were correctly localized to the trunk region on regional analysis. Changes in DXA estimates of mean total lean tissue, 1.78 +/- 0.94 kg, and trunk lean tissue, 1.87 +/- 0.84 kg, were very similar to the actual change in body weight. However, the DXA estimate of change in total soft tissue, 2.11 +/- 0.44 kg, was significantly greater than the change in body weight by 0.3 kg (P < 0.005); the difference was accounted for by a tendency for a reduction in the estimate of body fat affecting the trunk region after drainage of dialysate. DXA was also less good at detecting changes in individual subjects. Estimates of total and regional bone mineral content and bone mineral density were not affected by the drainage of the dialysis fluid.

Spatial distribution of femoral bone mineral in dual energy X-ray absorptiometry images: a possible technique to improve discrimination between normal and osteoporotic patients

The measurement of bone mineral density (BMD) using dual energy X-ray absorptiometry (DXA) provides an indicator of subsequent risk of hip fracture, but because of the significant overlap of measurements obtained from osteoporotic and control groups its predictive power is limited. The radiographic technique of Singh grading for the assessment of femoral osteoporosis utilizes information about the distribution of trabecular bundles, but the morphological information available in the DXA image has not previously been analysed. In this study of DXA images from 64 individuals (32 controls and 32 classified as osteoporotic) a subjective grading technique analogous to Singh grading is proposed, and quantitative measurements are made of image features corresponding to two of the categories. Discrimination was assessed using receiver operating characteristic (ROC) curves: the best discrimination was by spinal BMD (Az = 0.85 +/- 0.05) a performance equalled by one of the new parameters; the subjective grading method (Az = 0.79 +/- 0.07) performed as well as measurements of BMD in the femur. These results suggest that although the alternative measures do not improve on the discrimination possible using spinal BMD, morphological information from the hip itself may in the future have a place in the assessment of bone quality.

Specific cleavage of immunoglobulin G by copper ions

The hinge region of a recombinant-DNA-produced human IgG1 (Campath 1H) is specifically cleavable at a single copper-sensitive peptide bond, yielding a distinct fragment resolved by size-exclusion high-performance liquid chromatography. This novel metal ion-catalysed cleavage at slightly alkaline pH is inhibited by EDTA and its rate is reduced at slightly acidic conditions (pH 5-6) and accelerated by increasing concentrations of cupric ion and higher temperature. Complete cleavage was observed after incubation at pH 8 for 24 h with 1 mM CuCl2. Sequence analysis determined the cleavage site to be the Lys226-Thr227 bond in the hinge-region sequence DKTHT. Cleavage of other IgGs was observed to varying degrees, and specific cleavage of synthetic peptides containing this pentapeptide sequence was also observed.

Surgical resection of primary soft-tissue sarcoma. Incidence of residual tumour in 95 patients needing re-excision after local resection

We reviewed retrospectively 236 consecutive patients seen in our soft-tissue sarcoma clinic. Of these, 95 had had a primary soft-tissue sarcoma excised elsewhere, but with histologically inadequate resection margins. All these patients had a secondary and wider re-excision. The tissues removed at the secondary re-excision were examined histologically for the presence of residual tumour. Definite tumour tissue was found in 29 of 55 lower-limb specimens, 16 of 25 upper-limb, 7 of 10 trunk and 4 of 5 head and neck specimens. In 31 cases some residual tumour was visible macroscopically, and in 56 of the 95 patients (59%) the primary tumour had been incompletely excised. Our results indicated that surgical assessment of the adequacy of excision is very inaccurate and that most local recurrences are the consequence of inadequate primary surgery. The large number of patients who had inadequate initial treatment emphasises the need for a co-ordinated multidisciplinary approach to the management of patients with soft-tissue sarcoma.

Hippocampal vulnerability to stress and aging: possible role of neurotrophic factors

Chronic stress can accelerate age-related damage to the hippocampus. Adrenal glucocorticoids are thought to be responsible for this damage because of their ability to compromise energy metabolism and make neurons more vulnerable to glutamate excitotoxicity. Additional mechanisms by which stress or glucocorticoids could damage the hippocampus are considered in the context of recent evidence that stress regulates neurotrophic factor expression in the brain. Stress has been found to decrease brain-derived neurotrophic factor (BDNF) mRNA in the hippocampus, and this may contribute to stress-induced damage in this and other brain areas. Nerve growth factor (NGF) and neurotrophin-3 (NT-3) are increased by stress and glucocorticoids perhaps as a compensatory response to stress-induced damage. Because neurotrophic factors can protect the brain from a variety of traumatic insults, it is likely that they might also be effective in preventing or reversing glucocorticoid-induced damage to the hippocampus.

In vitro anticancer activity of fruit extracts from Vaccinium species

Fruit extracts of four Vaccinium species (lowbush blueberry, bilberry, cranberry, and lingonberry) were screened for anticarcinogenic compounds by a combination of fractionation and in vitro testing of their ability to induce the Phase II xenobiotic detoxification enzyme quinone reductase (QR) and to inhibit the induction of ornithine decarboxylase (ODC), the rate-limiting enzyme in polyamine synthesis, by the tumor promoter phorbol 12-myristate 13-acetate (TPA). The crude extracts, anthocyanin and proanthocyanidin fractions were not highly active in QR induction whereas the ethyl acetate extracts were active QR inducers. The concentrations required to double QR activity (designated CDqr) for the ethyl acetate extracts of lowbush blueberry, cranberry, lingonberry, and bilberry were 4.2, 3.7, 1.3, and 1.0 microgram tannic acid equivalents (TAE), respectively, Further fractionation of the bilberry ethyl acetate extract revealed that the majority of inducer potency was contained in a hexane/chloroform subfraction (CDqr = 0.07 microgram TAE). In contrast to their effects on QR, crude extracts of lowbush blueberry, cranberry, and lingonberry were active inhibitors of ODC activity. The concentrations of these crude extracts needed to inhibit ODC activity by 50% (designated IC50) were 8.0, 7.0, and 9.0 micrograms TAE, respectively. The greatest activity in these extracts appeared to be contained in the polymeric proanthocyanidin fractions of the lowbush blueberry, cranberry, and lingonberry fruits (IC50 = 3.0, 6.0, and 5.0 micrograms TAE, respectively). The anthocyanidin and ethyl acetate extracts of the four Vaccinium species were either inactive or relatively weak inhibitors of ODC activity. Thus, components of the hexane/chloroform fraction of bilberry and of the proanthocyanidin fraction of lowbush blueberry, cranberry, and lingonberry exhibit potential anticarcinogenic activity as evaluated by in vitro screening tests.

A portable system for measuring bone mineral density in the pre-term neonatal forearm

Current systems used to measure bone mineral content (BMC) in the neonate have the major drawback that the child must be well enough to be moved to the scanner. Consequently, low birth weight pre-term neonates, a group at particular risk of mineral compromise, cannot be measured. This paper describes a portable neonatal bone mineral device capable of measuring bone mineral in the incubator. It uses a radiation sensitive, charge coupled device (CCD) to acquire a bone mineral image enabling bone mineral to be measured at various sites. It measures bone mineral density (BMD) with a precision of 5.5 mg cm-2 in vivo, reduced to 7.5 mg cm-2 when repositioning between scans is taken into account. The procedure takes under 5 min with an image acquisition time of 30 s and an absorbed radiation dose to skin of 6 microSv. Calibration has been undertaken with aluminium foils of differing thickness to confirm the linearity of the system throughout the intended measurement range. A regression line fitted to the data demonstrated linearity and correlation between BMD and aluminium thickness with r = 0.99 (p < 0.0001). Preliminary measurements on pre-term neonates show values of BMD ranging from 43 to 115 mg cm-2 in babies aged 23-41 weeks post-conception. These figures are within the linear range of the system.