A guide to defining and implementing protocols for the welfare assessment of laboratory animals: eleventh report of the BVAAWF/FRAME/RSPCA/UFAW Joint Working Group on Refinement

The refinement of husbandry and procedures to reduce animal suffering and improve welfare is an essential component of humane science. Successful refinement depends upon the ability to assess animal welfare effectively, and detect any signs of pain or distress as rapidly as possible, so that any suffering can be alleviated. This document provides practical guidance on setting up and operating effective protocols for the welfare assessment of animals used in research and testing. It sets out general principles for more objective observation of animals, recognizing and assessing indicators of pain or distress and tailoring these to individual projects. Systems for recording indicators, including score sheets, are reviewed and guidance is set out on determining practical monitoring regimes that are more likely to detect any signs of suffering. This guidance is intended for all staff required to assess or monitor animal welfare, including animal technologists and care staff, veterinarians and scientists. It will also be of use to members of ethics or animal care and use committees. A longer version of this document, with further background information and extra topics including training and information sharing, is available on the Laboratory Animals website.

The mas oncogene as a neural peptide receptor: expression, regulation and mechanism of action

The human mas oncogene, which renders transfected NIH/3T3 cells tumorigenic, was identified as a subtype of angiotensin receptor by transient expression in Xenopus oocytes and stable expression in the mammalian neuronal cell line, NG115-401L. The mas receptor preferentially recognizes angiotensin III, and is expressed at high levels in brain. The mas/angiotensin receptor functions through the breakdown of inositol lipids and can drive DNA synthesis, unlike another inositol-linked peptide receptor, that for bradykinin. Comparative analysis of several early biochemical events elicited by either angiotensin or bradykinin stimulation of mas-transfected cells has not indicated a specific difference correlated with mitogenic activity. In particular, the inositol lipid kinase, phosphatidylinositol-3-kinase, thought to be involved in the mitogenic mechanism of platelet-derived growth factor receptors, is unaffected by activation of mas. These results have shown that a proto-oncogene encodes a neural peptide receptor, indicating that peptide receptors may be involved in differentiation and proliferation processes, as are other identified proto-oncogenes.

Genotypes of Cryptosporidium from Sydney water catchment areas

AIMS

Currently cryptosporidiosis represents the major public health concern of water utilities in developed nations and increasingly, new species and genotypes of Cryptosporidium are being identified in which the infectivity for humans is not clear. The complicated epidemiology of Cryptosporidium and the fact that the majority of species and genotypes of Cryptosporidium cannot be distinguished morphologically makes the assessment of public health risk difficult if oocysts are detected in the raw water supplies. The aim of this study was to use molecular tools to identify sources of Cryptosporidium from the Warragamba catchment area of Sydney, Australia.

METHODS AND RESULTS

Both faecal and water samples from the catchment area were collected and screened using immunomagnetic separation (IMS) and immunofluorescence microscopy. Samples that contained Cryptosporidium oocysts were genotyped using sequence and phylogenetic analysis of the 18S rDNA, and the heat-shock (HSP-70) gene. Analysis identified five Cryptosporidium species/genotypes including C. parvum (cattle genotype), C. suis, pig genotype II, the cervid genotype and a novel goat genotype.

CONCLUSIONS

Monitoring and characterization of the sources of oocyst contamination in watersheds will aid in the development and implementation of the most appropriate watershed management policies to protect the public from the risks of waterborne Cryptosporidium.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study has shown that quantification by IMS analysis can be combined with the specificity of genotyping to provide an extremely valuable tool for assessing the human health risks from land use activities in drinking water catchments.

Intramuscular tenotomy of flexor digitorum superficialis in the distal forearm after surgical excision of dupuytren's disease

Contracture of the proximal interphalangeal joint after surgery to excise Dupuytren's disease, despite release of the contributory structures within the finger, can be caused by flexor digitorum superficialis (FDS) contracture. We describe five cases where FDS contracture was released by intramuscular tenotomy in the distal forearm. Standard postoperative therapy for Dupuytren's fasciectomy was used and clinical review showed improved finger extension with no loss of strength. We suggest that intramuscular tenotomy of FDS in the forearm can be used safely where indicated after excision of the Dupuytren's disease.

Proportional assist ventilation as an aid to exercise training in severe chronic obstructive pulmonary disease

BACKGROUND

The effects of providing ventilatory assistance to patients with severe chronic obstructive pulmonary disease (COPD) during a high intensity outpatient cycle exercise programme were examined.

METHODS

Nineteen patients (17 men) with severe COPD (mean (SD) forced expiratory volume in 1 second (FEV(1)) 27 (7)% predicted) underwent a 6 week supervised outpatient cycle exercise programme. Ten patients were randomised to exercise with ventilatory assistance using proportional assist ventilation (PAV) and nine (two women) to exercise unaided. Before and after training patients performed a maximal symptom limited incremental cycle test to determine peak work rate (Wpeak) followed by a constant work rate (CWR) test at 70% of Wpeak achieved in the baseline incremental test. Minute ventilation (VE), heart rate, and arterialised venous plasma lactate concentration [La(+)] were measured before and after each test.

RESULTS

Mean training intensity (Wt/Wpeak) at 6 weeks was 15.2% (95% CI 3.2 to 27.1) higher in the group that used ventilatory assistance (p=0.016). Peak work rate after training was 18.4% (95% CI 6.4 to 30.5) higher (p=0.005) in the assisted group (p=0.09). [La(+)] at an identical workload after training was reduced by 30% (95% CI 16 to 44) in the assisted group (p=0.002 compared with baseline) and by 11% (95% CI -7 to 31) (p=0.08 compared with baseline) in the unassisted group (mean difference 18.4% (95% CI 3.3 to 40), p=0.09). A significant inverse relationship was found between reduction in plasma lactate concentration (DeltaL) at an equivalent workload after training during the CWR test and Wt/Wpeak achieved during the last week of training (r=-0.7, p=0.0006).

CONCLUSIONS

PAV enables a higher intensity of training in patients with severe COPD, leading to greater improvements in maximum exercise capacity with evidence of true physiological adaptation.

A novel clinical test of respiratory muscle endurance

Impaired respiratory muscle endurance (RME) could reduce exercise tolerance and contribute to ventilatory failure. The aim of the present study was to develop a clinically-feasible method to measure RME using negative-pressure inspiratory-threshold loading. It was hypothesized that endurance time (tlim) could be predicted by normalizing oesophageal pressure-time product (PTP) per total breath cycle (PTPoes) for maximum oesophageal pressure (Poes,max); the load/capacity ratio. The corresponding mouth pressures, PTPmouth and Pmouth,max were also measured. The RME test was performed on 30 healthy subjects exposed to the same target pressure (70% of Poes,max). Eight patients with systemic sclerosis/interstitial lung disease were studied to assess the validity and acceptability of the technique. Normal subjects showed a wide intersubject variation in tlim (coefficient of variation, 69%), with a linear relationship demonstrated between log tlim and PTPoes/Poes,max (r=0.88). All patients with systemic sclerosis/interstitial lung disease had normal respiratory muscle strength, but six out of eight had a reduction in RME. In conclusion, endurance time can be predicted from the load/capacity ratio, over a range of breathing strategies; this relationship allows abnormal respiratory muscle endurance to be detected in patients. Oesophageal and mouth pressure showed a close correlation, thus suggesting that the test could be applied noninvasively.

A novel measuring system for the determination of paramagnetic particle labels for use in magneto-immunoassays

Coated micrometer-sized paramagnetic particles (PMPs) are readily available and widely used in immunoassays, mainly for separation and as a solid phase. We have described in a separate paper a model sandwich assay in which approximately 1 x 10(5) to 1 x 10(6) PMPs (2.8 microm diameter) are immobilised on a plastic strip at the end of the assay. In this paper, we describe the design of an instrument that is capable of determining the number of PMPs on the plastic strip. The paper also describes a method of making standard plastic strips with known numbers of PMPs on them. A strip, when placed in a coil of wire in parallel with a capacitor, causes the resonant frequency of the coil to decrease because of the presence of the PMPs. The decrease in frequency relates directly to the number of PMPs on the strip. A circuit based on a voltage-controlled oscillator and a phase-locked loop is used to accurately measure the resonant frequency of the coil. The instrument is capable of detecting at least 1 x 10(5) PMPs immobilised on a plastic strip and has a linear response (r=0.99) for up to at least 3.33 x 10(6) PMPs. In terms of the iron content of the PMPs, the detection limit is approximately equal to 1.2 microg Fe in the paramagnetic particles and the sensitivity is approximately equal to 3 Hz per microg of Fe. The instrument is small and compact and together with a suitable magneto-immunoassay will have many applications, including near-patient monitoring.

The use of coated paramagnetic particles as a physical label in a magneto-immunoassay

An ideal label for use in an immunoassay would require no further chemical or electromagnetic stimulation prior to its detection and would be free from interference from the sample matrix. Micron sized paramagnetic particles are able to perturb magnetic fields. This perturbation can be directly detected using a suitable electronic device and is independent of the sample matrix. In this study coated paramagnetic particles were used as a physical label in a non-competitive solid phase "sandwich" assay for the detection of human transferrin. The transferrin acted as a "biological bridge" allowing a dose dependant immobilization of the paramagnetic particles to a polyethylene terephthalate solid phase. Quantitation of the paramagnetic label was achieved using an electronic detection system allowing a linear dose response with a femtomolar detection limit (260 fmol).

Cardiovascular and hypothalamic-pituitary-adrenal axis development in late gestation fetal sheep and young lambs following modest maternal nutrient restriction in early gestation

The effect of a 15% reduction in maternal nutrition for the first 70 days of gestation on cardiovascular and hypothalamic-pituitary-adrenal (HPA) axis responses to administration of corticotropin releasing hormone (CRH) + arginine vasopressin (AVP) was studied at 128 +/- 0.7 days gestation in fetal sheep and postnatally, at 85 +/- 4.5 days in young lambs. The effect on the fetal cardiovascular response to acute hypoxaemia was also examined. Under basal conditions, fetal heart rate (FHR) was reduced (P < 0.05) and basal femoral artery vascular resistance (FVR) was increased (P < 0.05) in fetuses of dietary-restricted (R) ewes compared with controls (C). Fetal mean arterial pressure (MAP) was similar in both groups. Femoral artery vascular resistance was also greater during hypoxaemia in R fetuses compared with C fetuses (P < 0.05), suggesting that chemoreflex mechanisms were augmented in the R group. The fetal ACTH response to CRH + AVP was similar in both groups. However, cortisol responses to CRH + AVP were smaller in R fetuses compared with C fetuses (P<0.05). Postnatally, basal MAP (P < 0.05), and ACTH (P < 0.01) and cortisol (P < 0.001) responses were greater in R lambs compared with C lambs. It was concluded that modest maternal undernutrition during pregnancy alters development of the cardiovascular system, producing elevated blood pressure in postnatal life. Development of the HPA axis is also altered, with reduced activity during fetal life, but increased activity postnatally. The data suggest that the HPA axis may play a role in mediating the elevation of MAP in R lambs.

Isolation and characterization of a novel type of neurotoxic peptide from the venom of the South African scorpion Parabuthus transvaalicus (Buthidae)

The venom of the South African scorpion Parabuthus transvaalicus was characterized using a combination of mass spectrometry and RP-HPLC separation and bioassays. The crude venom was initially separated into 10 fractions. A novel, moderately toxic but very high abundance peptide (birtoxin) of 58 amino-acid residues was isolated, identified and characterized. Each purification step was followed by bioassays and mass spectroscopy. First a C4 RP-HPLC column was used, then a C18 RP Microbore column purification resulted in > 95% purity in the case of birtoxin from a starting material of 230 microg of crude venom. About 12-14% of the D214 absorbance of the total venom as observed after the first chromatography step was composed of birtoxin. This peptide was lethal to mice at low microgram quantities and it induced serious symptoms including tremors, which lasted up to 24 h post injection, at submicrogram amounts. At least seven other fractions that showed different activities including one fraction with specificity against blowfly larvae were identified. Identification of potent components is an important step in designing and obtaining effective anti-venom. Antibodies raised against the critical toxic components have the potential to block the toxic effects and reduce the pain associated with the scorpion envenomation. The discovery of birtoxin, a bioactive long chain neurotoxin peptide with only three disulfide bridges, offers new insight into understanding the role of conserved disulfide bridges with respect to scorpion toxin structure and function.

Maternal undernutrition during the periconceptual period increases plasma taurine levels and insulin response to glucose but not arginine in the late gestational fetal sheep

Maternal undernutrition throughout gestation impairs pancreatic function in the offspring. The influence of periconceptual maternal undernutrition on fetal insulin responses to secretogues in late gestation is unknown. Romney ewes were fed concentrates at 1-2% of body weight/d (UN) or 3-4% of body weight/d (N) from -61 d to +30 d from mating. From 30 d gestation all ewes were fed at 3-4% of body weight/d. At 119 d gestation singleton fetuses (UN; n = 12, N; n = 10) underwent intravenous glucose (1.5 g) and arginine (300 mg) challenge tests. Paired maternal and fetal blood samples were collected over 60 min. Fetal plasma insulin area under the curve (AUC) was larger in UN than in N fetuses during glucose challenge (4.5 +/- 0.6 vs. 2.9 +/- 0.5 nM, p < 0.05) but was not different during arginine challenge. Maternal and fetal plasma taurine concentrations were higher in UN than N (maternal; 110 +/- 11 vs. 75 +/- 8 microM, fetal; 99 +/- 13 vs. 56 +/- 5 microM, both p < 0.05). Maternal periconceptual undernutrition influences fetal insulin secretion without affecting fetal size. The larger plasma insulin responses in UN fetuses could reflect accelerated maturation of pancreatic beta cells or an alteration of other mechanisms regulating insulin secretion. The role of taurine in fetal pancreatic beta cell development requires further investigation.

Undernutrition during the first half of gestation increases the predominance of fetal tissue in late-gestation ovine placentomes

OBJECTIVE

To investigate, in sheep, the effects of maternal undernutrition during the first half of pregnancy on placental growth and development and fetal growth.

STUDY DESIGN

Six ewes (R) were subjected to a 15% reduction in nutrient intake for the first 70 days of gestation and thereafter received the recommended daily intake. Another group of six ewes (C) received the recommended daily intake throughout pregnancy. At 130 days gestation the ewes were killed and morphological and morphometrical measurements were carried out on the placenta and fetus.

RESULTS

Undernutrition resulted in a significant alteration in placental morphology, which was seen as increased growth of the fetal side of the placenta in R animals. However, fetal size in late gestation was not affected by the undernutrition, suggesting that placental adaptation was successful in maintaining fetal growth.

CONCLUSION

Placental adaptations, including changes in gross morphology, may preserve fetal growth if maternal undernutrition is not severe. The mechanisms remain to be elucidated.

Maternal undernutrition in early gestation alters molecular regulation of the hypothalamic-pituitary-adrenal axis in the ovine fetus

We have demonstrated previously that plasma adrenocorticotropin hormone and cortisol responses to exogenous and endogenous stimuli are reduced in fetuses of mildly undernourished ewes. In the present study, we examined the molecular regulation of fetal hypothalamic-pituitary-adrenal (HPA) axis function at 127-130 days gestation (dGA) following 15% reduction in maternal nutrition between 0 and 70 dGA. Using in situ hybridization, we found that corticotropin releasing hormone (CRH) mRNA expression in the hypothalamic paraventricular nucleus (PVN) was lower in fetuses from nutrient restricted ewes than in controls. Restricted fetuses also had greater levels of mRNA encoding preproenkephalin (PENK) and magnocellular arginine vasopressin (AVP) in the PVN. Expression of oxytocin mRNA and parvocellular AVP mRNA in the PVN and pro-opiomelanocortin mRNA in the pituitary were unchanged. Glucocorticoid receptor mRNA expression was unaltered at the PVN, but was reduced (> 40%) in the anterior pituitary of restricted fetuses. Northern blot analysis demonstrated that levels of adrenal P450scc mRNA and P450(C17) mRNA were not different between the groups. We conclude that the reduction in HPA function reported previously is mediated, at least in part, by a decrease in expression of CRH mRNA and increase in PENK mRNA in the PVN.

Diaphragm strength in acute systemic lupus erythematosus in a patient with paradoxical abdominal motion and reduced lung volumes

Diaphragmatic weakness is reported as a common feature of the shrinking lung syndrome of systemic lupus erythematosus (SLE). However, in chronic stable SLE it has been shown that, despite poor performance of voluntary tests of diaphragm strength, twitch pressures obtained by stimulating the phrenic nerves are normal. We present a patient with acute SLE and pulmonary involvement who, despite having paradoxical abdominal motion and low maximal inspiratory pressures during voluntary manoeuvres, had normal diaphragm strength when assessed with magnetic stimulation of the phrenic nerves. Following immunosuppressive therapy symptoms and lung function improved, yet diaphragm contractility remained normal and unchanged. We suggest that this case supports the view that reduced diaphragm muscle contractility per se does not explain the small volume lungs and respiratory symptoms in patients with acute SLE.

Effects of undernutrition in early pregnancy on systemic small artery function in late-gestation fetal sheep

OBJECTIVE

The aim of this study was to investigate functional development of small arteries from the skeletal circulation of fetal sheep and to determine whether maternal undernutrition affects responses to vasoconstrictive and vasodilatory agonists in arteries from the late-gestation fetus.

STUDY DESIGN

We investigated vasoconstrictive and vasodilatory responses of isolated small (approximately 300 microm) arteries from the femoral vascular bed of fetal sheep and from late-gestation pregnant ewes. Ewes were fed either 100% of the nutritional requirement throughout pregnancy (control group) or a restricted diet of 85% or 50% of the nutritional requirement for the first 70 days of pregnancy. For the remainder of pregnancy all ewes were fed the complete diet.

RESULTS

Among control group animals vasoconstriction in response to norepinephrine was well developed in fetuses at 0.6 and 0.9 gestation with respect to that in the ewes. When expressed as a percentage of the response to 125-mmol/L potassium (to correct for differences in vessel size and muscle mass), maximum constriction in response to norepinephrine was greater in fetal vessels from 0.9 gestation than in either those at 0.6 gestation or those of the ewes. Endothelium-dependent vasorelaxation responses to acetylcholine and bradykinin were also well developed in fetuses at 0.6 and 0.9 gestation and were similar to those in the ewes. In fetuses at 0.9 gestation the 50% nutritional restriction of the ewe led to blunted endothelium-dependent vasodilatation in response to acetylcholine and blunted endothelium-independent vasodilatation in response to sodium nitroprusside. Responses in the fetuses at 0.9 gestation in which the ewes were fed a restricted diet of 85% were normal.

CONCLUSION

This study shows that from midgestation onward small arteries from the skeletal circulation of the fetal sheep have the functional capacity to respond to norepinephrine and endothelium-dependent vasodilators (eg, acetylcholine and bradykinin). The blunted responses to acetylcholine and sodium nitroprusside in the fetuses at 0.9 gestation among the group of dietarily restricted ewes (restricted diet of 50% group) were indicative of impaired vascular smooth muscle sensitivity to nitric oxide. This defect may contribute to the development of hypertension in later life.

Inspiratory pressure support prolongs exercise induced lactataemia in severe COPD

BACKGROUND

A physiological benefit from pulmonary rehabilitation in chronic obstructive pulmonary disease (COPD) is more probable if exercise is performed above the lactate threshold. This study was undertaken to investigate whether it was possible to extend the lactataemia of exercise using non-invasive inspiratory pressure support (IPS).

METHODS

Plasma lactate levels were measured in eight men with severe COPD who performed two treadmill walks at an identical constant work rate to a condition of severe dyspnoea; the second walk was supported by IPS.

RESULTS

Mean plasma lactate levels before the free and IPS assisted walks were 1.65 mmol/l and 1. 53 mmol/l, respectively (p = NS). Lactate levels increased during both walks to 2.96 mmol/l and 2.42 mmol/l, respectively (p = 0.01 for each) but the duration of the IPS assisted walk was significantly greater than the free walk (13.6 minutes versus 5.5 minutes, p = 0.01).

CONCLUSIONS

Patients with severe COPD can sustain exercise induced lactataemia for longer if assisted with IPS. This technique may prove to be a useful adjunct in pulmonary rehabilitation.

Effect of maternal undernutrition in early gestation on ovine fetal blood pressure and cardiovascular reflexes

Human epidemiological and animal experimental studies suggest that maternal undernutrition during pregnancy may alter cardiovascular development of the offspring. The extent to which these effects involve changes in fetal cardiovascular function and whether they are necessarily linked to reduced fetal growth is unknown. In sheep, we investigated the effect of a 15% reduction in maternal global nutrition for the first 70 days of gestation (term = 147 days) on fetal blood pressure development, baroreflex control of fetal heart rate (FHR), and cardiovascular responses to acute hypoxemia in late gestation. Basal mean arterial pressure (P < 0.05), systolic blood pressure (P < 0.05), diastolic blood pressure (P < 0.05), and rate-pressure product (P < 0.001) were significantly lower in fetuses of nutritionally restricted ewes (R) compared with controls (C). FHR was not altered. The operating point for the fetal baroreflex was significantly lower in R fetuses compared with C (P < 0.01), but there was no difference between the groups in the cardiovascular response to hypoxemia. We conclude that mild maternal undernutrition alters fetal cardiovascular development, producing low blood pressure and resetting of baroreflex control mechanisms. This effect occurs without any changes in fetal growth or blood gas status.

Effect of lung volume on the oesophageal diaphragm EMG assessed by magnetic phrenic nerve stimulation

Previous studies have shown conflicting results on the effect of lung volume on the diaphragm compound muscle action potential (CMAP). Consequently, the ability to quantify the oesophageal diaphragm electromyography (EMG) has been questioned. If lung volume changes have little effect on the diaphragm CMAP the accurate measurement of voluntary EMG, as an index of respiratory drive, may be possible. Furthermore, the measurement of CMAP could provide useful clinical information when evaluating patients with neuromuscular disease. To reassess the effect of lung volume on the oesophageal diaphragm CMAP, six normal subjects were studied using an oesophageal catheter incorporating seven electrodes (number one being proximal and seven distal) that were 1 cm in length and 1 cm apart. Electrode number three was positioned at the centre of the electrically active region of the diaphragm (EARdi) at functional residual capacity (FRC). The diaphragm CMAP elicited by bilateral magnetic stimulation of the phrenic nerves was simultaneously recorded from four electrode pairs. Pair one was created from electrodes one and three, pair two from electrodes two and four, pair three from electrodes three and five, and pair four from electrodes five and seven. Phrenic nerve stimulation was at residual volume (RV), FRC, FRC+1.0 L, FRC+2.0 L, and total lung capacity (TLC). The CMAP recorded from pair one was least influenced by changes in lung volume and the amplitude was 2.41+/-0.39 (mean+/-SD), 2.60+/-0.27, 2.64+/-0.29, and 2.71+/-0.45 mV at RV, FRC, FRC+1.0 L and FRC+2.0 L, respectively. At TLC the CMAP was more variable. The CMAP amplitude recorded from pair two increased with increasing lung volume and at FRC+2.0 L was 3.7 times larger than that at FRC. Pair four usually recorded substantially smaller CMAPs at all lung volumes. This study shows that the diaphragm compound muscle action potential recorded from an oesophageal electrode just above the diaphragm is relatively stable over the lung volume range residual volume to functional residual capacity+2.0 L.

Effect of maternal nutrient restriction in early gestation on responses of the hypothalamic-pituitary-adrenal axis to acute isocapnic hypoxaemia in late gestation fetal sheep

Epidemiological and experimental evidence suggests that maternal undernutrition during pregnancy may alter development of fetal organ systems. We have demonstrated previously that fetal hypothalamic-pituitary-adrenal (HPA) axis responses to exogenous corticotropin-releasing hormone (CRH) + arginine vasopressin (AVP), or adrenocorticotrophin hormone (ACTH), are reduced in fetuses of mildly undernourished ewes. To examine these effects further we tested HPA axis responses to acute isocapnic hypoxaemia in fetal sheep at 114-129 days gestation (dGA), following 15% reduction in maternal nutritional intake between 0 and 70 dGA. Fetuses from control (C) and nutrient-restricted (R) ewes were chronically catheterised and plasma ACTH and cortisol responses were determined at 114-115, 120-123 and 126-129 dGA during hypoxaemia (1 h) induced by lowering the maternal inspired O2 fraction (FI,O2). Basal plasma cortisol concentrations and HPA axis responses at 114-115 and 120-123 dGA did not differ between C and R fetuses. At 126-129 dGA, both plasma ACTH (P < 0.01) and cortisol (P < 0.05) responses were smaller in R fetuses compared to C fetuses. Fetal blood gas status, fetal body weight, body proportions and organ weights did not differ between the groups. We conclude that mild maternal undernutrition alters development of the fetal HPA axis producing a reduction in pituitary and adrenal responsiveness to endogenous stimuli.

Effect of maternal nutrient restriction in early gestation on development of the hypothalamic-pituitary-adrenal axis in fetal sheep at 0.8-0.9 of gestation

The fetal hypothalamic-pituitary-adrenal (HPA) axis has numerous key roles in development. Epidemiological data have linked adverse prenatal nutrition with altered organ development and increased incidence of disease in adult life. We studied HPA axis development in resting and stimulated states in late gestation fetal sheep, following 15% reduction in maternal nutritional intake over the first 70 days of gestation (dGA). Fetuses from control (C) and nutrient-restricted (R) ewes were chronically catheterised and response profiles for ACTH and cortisol were determined at 113-116 and 125-127 dGA after administration of corticotrophin releasing hormone (CRH) and arginine vasopressin (AVP). At 126-128 dGA cortisol profiles were also determined following ACTH administration. Basal ACTH and cortisol concentrations were not different between C and R fetuses. In R fetuses, ACTH response to CRH+AVP was significantly smaller at 113-116 dGA (P<0.01), and cortisol responses were smaller at both 113-116 dGA (P<0.01) and 125-127 dGA (P<0.0001). Cortisol response to ACTH was also smaller in R fetuses (P<0.001). We conclude that, in late gestation fetal sheep, pituitary and adrenal responsiveness is reduced following modest maternal nutrient restriction in early gestation.

Comparison of usefulness between exercise capacity and echocardiographic indexes of left ventricular function in cardiac amyloidosis

In patients with primary systemic amyloidosis (AL), the echocardiographic assessment of ventricular function alone does not always correspond to patients' symptoms and functional status. Peak oxygen uptake and anaerobic threshold (AT), in contrast, constitute 2 objective, reliable and reproducible indicators of functional status in patients with circulatory failure. Thirty-two consecutive patients (mean age 50 +/- 13 years) with histologic evidence of systemic primary AL were studied (29 AL, 3 hereditary). There were 16 with echocardiographic features of cardiac infiltration (group I) and 16 without (group II). Twenty age- and gender-matched healthy subjects were also studied for comparison. Of the 32 patients, 12 were in New York Heart Association functional class I, 9 were in class II, and 11 were in class III. Each subject underwent 2-dimensional and Doppler echocardiography and cardiopulmonary exercise testing using a modified Bruce protocol. Left atrial (LA), left ventricular (LV) dimensions, wall thickness, and LV fractional shortening, as well as transmitral flow velocities and their E/A ratio were measured. Peak oxygen consumption (VO2max [ml/kg/min]), AT (ml/kg/min), and exercise duration (seconds) were also measured. VO2max and AT were lower in patients with AL than in controls (20.8 +/- 7.0 vs 35.0 +/- 8.5, p <0.001 and 13.1 +/- 3.7 vs 27.0 +/- 4.2, p <0.001, respectively). As a group, symptomatic patients had lower VO2max, AT, and exercise duration than those without symptoms (17.1 +/- 3.6 vs 27.0 +/- 6.9, p = 0.0001, 11.1 +/- 2.1 vs 16.2 +/- 3.6, p = 0.0001, and 489 +/- 235 vs 843 +/- 197, p = 0.0001, respectively), whereas LV dimensions only showed a small difference (p = 0.03). VO2max, AT, and exercise duration of patients in functional class I were higher than those in functional classes II and III (p = 0.01, p <0.05, and p = 0.007, respectively). Asymptomatic patients had lower VO2max, AT, and exercise duration than controls (p <0.0001). VO2max, AT, and exercise duration were poorly related to LA diameter, LV dimensions, fractional shortening, wall thickness, peak velocities of E and A waveforms, and E/A ratio. Patients with VO2max > 15 ml/kg/min had a better survival than patients with VO2max < 15 ml/kg/min. Thus, in patients with primary systemic AL, cardiorespiratory exercise testing is the preferred way of assessing functional capacity. Echocardiographic Doppler indexes at rest are not predictive of a patient's symptoms and exercise capacity. Furthermore, VO2max is a strong independent predictor of survival in these patients.

Echocardiographic features of primary, secondary and familial amyloidosis

BACKGROUND

Currently recognized types of amyloidosis include primary, familial and secondary, each of which may affect the heart. There may be differences in the heart response to the deposition of amyloid fibrils in these three forms of the disease.

MATERIALS AND METHODS

Over a period of 10 years (1985-95), 28 consecutive patients with primary, 11 with secondary and 17 with familial amyloidosis were studied at the Departments of Cardiology of Laiko and Hammersmith Hospitals. The diagnosis of amyloidosis was confirmed by biopsies of subcutaneous fat, rectum, kidney, bone marrow, gum or sural nerve. Diagnosis of cardiac involvement was based on typical electrocardiographic and echocardiographic findings.

RESULTS

The left ventricular fractional shortening (%) was reduced in primary compared with familial or secondary amyloidosis (29.8 +/- 10.2 vs. 36.2 +/- 6.5 vs. 36 +/- 5.9, P < 0.05). The transmitral flow velocity pattern was compatible with abnormal relaxation in most patients in the three groups [primary 16 (57%), familial 11 (64. 7%), secondary 6 (54.5%), P = NS]. Right ventricular systolic dysfunction (right ventricular dP/dt < 220 mmHg s-1 or tricuspid annulus systolic excursion < 10 mm) was present in 8 (28.6%), 2 (11. 8%) and 0 patients. Patients with primary amyloidosis were followed up for 15 +/- 6 months. There were 12 deaths, and repeat echocardiography in the survivors revealed a significant deterioration of left ventricular systolic function (fractional shortening = 23.6% +/- 8.8%, P < 0.05 vs. baseline).

CONCLUSION

Primary amyloidosis is characterized by more severe cardiac involvement than the familial or secondary amyloidosis and has an ominous course.

Neuropsychological functioning in HIV-positive African-American women with a history of drug use

This preliminary investigation examined neuropsychological performance in a sample of human immunodeficiency virus (HIV)-positive and HIV-negative African-American women with a history of drug use. The study population was comprised of 10 HIV-negative, 9 asymptomatic HIV-positive, 13 symptomatic HIV-positive, and 10 acquired immunodeficiency virus (AIDS) patients. A neuropsychological battery designed to assess attention, psychomotor processing, verbal memory, and visual memory was administered to participants. No evidence of HIV-related cognitive impairment was found in patients in the early stages of HIV infection. Multivariate analyses of variance revealed significant deficits in psychomotor processing and verbal recall in persons with AIDS. These individuals showed greater difficulty in tasks requiring maintained attention and performed poorly on measures of immediate and delayed verbal recall. In contrast, HIV status was not related to visual memory, verbal recognition, or the number of errors made during a verbal recall task. The pattern of cognitive deficits observed in persons with AIDS resembles that commonly associated with subcortical pathology. The cognitive deficits observed were not related to depression or recentness of drug use.

Heat increment of feeding in Brunnich's guillemot

The rate of oxygen consumption (O2), respiratory quotient (RQ) and deep body temperature (TB) were recorded during a single, voluntary ingestion of Arctic cod Boreogadus saida (mean mass 18.9+/-1.1 g, s.e.m., N=13) by five postabsorptive Brunnich's guillemots (thick-billed murre, Uria lomvia). The birds were resting in air within their thermoneutral zone, and the fish were refrigerated to 0-2 degreesC. The rate of oxygen consumption increased by a factor of 1.4 during the first few minutes after ingestion, but there was no significant change in TB. Mean rate of oxygen consumption returned to preingestive levels 85 min after the birds ate the fish. The telemetered temperature of one fish reached TB within 20 min. This suggests that the persistent elevation in O2 over the next hour corresponded to the obligatory component of the heat increment of feeding (HIF) and was not related to heating the fish. Abdominal temperature increases after diving bouts in free-ranging common guillemots (common murre, Uria aalge) are possibly achieved through the HIF, since meals are processed at sea. Of the increase in O2 measured in the laboratory, it is calculated that 30 % is required to heat the fish, while 70 % is due to the HIF. In free-ranging birds, the excess heat provided by the HIF could contribute 6 % of the daily energy expenditure. This suggests that the HIF augments heat production in Uria spp. and thus reduces the energetic cost of thermoregulation.

Volume-sensitive taurine efflux from mammary tissue is not obliged to utilize volume-activated anion channels

Cell-swelling, induced by a hyposmotic shock, activates the release of taurine from lactating rat mammary tissue explants. The degree of stimulation of taurine efflux was dependent upon the extent of cell-swelling. Volume-sensitive taurine release was attenuated by the anion transport inhibitors NPPB, DIOA, DIDS, niflumate, flufenamate, mefenamate and diiodosalicylate but not by salicylate. Cell-swelling, following a hyposmotic challenge, did not increase the unidirectional efflux of radiolabelled I- or D-asparate from mammary tissue explants. The results suggest that although mammary tissue expresses a volume-sensitive amino acid transport system which is inhibited by anion transport blockers the pathway has no identity with volume-activated anion channels.

An amino-terminal truncated progesterone receptor isoform, PRc, enhances progestin-induced transcriptional activity

Previously we reported the identification of two unique progesterone receptor (PR) messenger RNA transcripts that encode a smaller PR isoform, termed the C-receptor (PRc). These two PR transcripts encode a protein that is N-terminally truncated, so that it lacks the first zinc finger of the DNA binding domain, but still contains a complete hormone binding region with sequences for dimerization and nuclear localization. We also have demonstrated the existence of a 60-kDa progestin-specific binding protein in progestin target cells using a monoclonal antibody directed to the C-terminus of PRs, suggesting that these two novel transcripts generate a truncated form of PR. In this paper, we address the hypothesis that the C-receptor arises from the initiation of translation of a methionine C-terminal to the methionine start sites that generate the larger 94-kDa A and 116-kDa B human PR isoforms. The studies shown here support the postulate that another downstream in-frame methionine within the PR-coding region can serve as a translation initiation site for the generation of a third PR protein. A partial PR complementary DNA, lacking the translation start sites for B- and A-receptors was translated in vitro. The synthetic protein product bound [3H]progestins and unlabeled progestins. The antiprogestin RU486 also competed for this binding. Transfection of this partial PR complementary DNA into PR-negative HeLa cells resulted in progestin-specific binding activity. Because the third PR isoform lacks the first zinc finger of the DNA binding domain, but contains sequences for dimerization, we reasoned that the C-receptor isoform would be transcriptionally in-active and not bind DNA directly. Surprisingly, however, in the presence of A- and/or B-receptors, we found that C-receptors can modulate the transcriptional activity of A- and/or B-receptors using a reporter gene. These studies emphasize that multiple receptor isoforms may have distinct biological properties, and that the truncated C-receptor may play a role in explaining some of the pleiotropic effects of progestins.

Separation of toxic peptides (microcystins) in capillary electrophoresis, with the aid of organic mobile phase modifiers

A capillary electrophoretic (CE) method incorporating sodium dodecyl sulphate (SDS)-organic modifier solvents in the CE buffer was developed for the detection of toxic cyclic heptapeptide toxins (microcystins) produced by blue-green algae (cyanobacteria). The applicability of these run buffers for the analysis of microcystins was evaluated and optimum conditions for separation were determined. The migration times, elution order and selectivity of the toxic peptides were influenced by modifying the composition of the electrophoretic buffer with organic solvents [0 to 20% (v/v)]. At maximum addition, the organic solvents with the exception of acetonitrile, increased the viscosity of the buffer solution. In contrast to the migration time of the other microcystins, that of microcystin-RR was not increased by the addition of 2-propanol to the buffer solution. Rather, microcystin-RR eluted more quickly with the increase in 2-propanol, thereby effecting changes in the elution order of the microcystins. In addition, this solvent resulted in comigration of microcystin-LR and microcystin-YR. No significant relationship was found between the elution order and separation and the structure of the toxic peptides studied in micellar electrokinetic capillary chromatography with an organic modifier in the buffer solution; but there is an agreement between the effects of the organic modifiers and their dipole moments. Parameters such as linearity, sensitivity and reproducibility were also evaluated. High-efficiency separations of toxic peptide molecules having equal or nearly equal mass to charge ratios have been achieved using SDS as an additive to the running buffer. The influence of the pH has been examined.

Insulin and ATP stimulate actin polymerization in U937 cells by a wortmannin-sensitive mechanism

ATP and insulin stimulate increases in phosphatidylinositol (3,4,5)-trisphosphate levels in myeloid-derived U937 cells. Quantification of FITC-phalloidin binding by fluorescence-activated cell sorting reveals that both ATP and insulin stimulate actin polymerization with distinctive kinetics in U937 cells. The response to ATP is rapid and dose-dependent with an EC50 of 200 nM, and is abolished by pre-incubation with the Ca2+ chelator BAPTA-AM. At 800 nM concentration, wortmannin, a potent inhibitor of phosphoinositide 3-kinase (PI3K), blocks the late, but not the early phase of actin polymerization stimulated by 100 nM ATP. Responses elicited by 10 micrograms/ml insulin are slower, smaller and more transient than responses to ATP, and are inhibited by preincubation with 100 nM wortmannin. Actin polymerization can also be stimulated by thapsigargin, but not by phorbol ester, providing further evidence for a role for Ca2+ in actin polymerization. These data implicate distinct Ca2+ and PI3K-mediated pathways in the regulation of actin polymerization.

Activation of the small GTP-binding proteins rho and rac by growth factor receptors

The small GTP-binding proteins, rho and rac, control signal transduction pathways that link growth factor receptors to the activation of actin polymerization. In Swiss 3T3 cells, rho proteins mediate the lysophosphatidic acid and bombesin-induced formation of focal adhesions and actin stress fibres, whilst rac proteins are required for the platelet-derived growth factor-, insulin-, bombesin- and phorbol ester (phorbol 12-myristate 13-acetate)-stimulated actin polymerization at the plasma membrane that results in membrane ruffling. To investigate the role of p85/p110 phosphatidylinositol 3-kinase in the rho and rac signalling pathways, we have used a potent inhibitor of this activity, wortmannin. Wortmannin has no effect on focal adhesion or actin stress fibre formation induced by lysophosphatidic acid, bombesin or microinjected recombinant rho protein. In contrast, it totally inhibits plasma membrane edge-ruffling induced by platelet-derived growth factor and insulin though not by bombesin, phorbol ester or microinjected recombinant rac protein. We conclude that phosphatidylinositol 3,4,5 trisphosphate mediates activation of rac by the platelet-derived growth factor and insulin receptors. The effects of lysophosphatidic acid on the Swiss 3T3 actin cytoskeleton can be blocked by the tyrosine kinase inhibitor, tyrphostin. Since tyrphostin does not inhibit the effects of microinjected rho protein, we conclude that lysophosphatidic acid activation of rho is mediated by a tyrosine kinase.

Activation of phosphoinositide 3-kinase is required for PDGF-stimulated membrane ruffling

BACKGROUND

There is substantial evidence that phosphoinositide 3-kinase (PI 3-kinase) is a critical component of signalling pathways used by the cell-surface receptors for a variety of mammalian growth factors and other hormones. The physiological product of this enzyme is a highly polar membrane lipid called phosphatidylinositol (3,4,5)-trisphosphate This lipid has been postulated to act as a second-messenger in cells but its putative targets are still unknown.

RESULTS

A particular rearrangement of actin filaments, which results in membrane ruffling, is elicited by the activation of PDGF beta-receptors expressed in cultured porcine aortic endothelial cells. We have found that this consequence of PDGF beta-receptor activation is inhibited by three independent manipulations of PI 3-kinase activity: firstly, by the deletion of tyrosine residues in the PDGF beta-receptor to which PI 3-kinase binds; secondly, by the overexpression of a mutant 85 kD PI 3-kinase regulatory subunit to which the catalytic kinase subunit cannot bind; and thirdly, by the addition of the fungal metabolite wortmannin, which is a potent inhibitor of the catalytic activity of PI 3-kinase.

CONCLUSIONS

These results argue strongly that phosphatidylinositol (3,4,5)-trisphosphate synthesis is required for growth-factor-stimulated membrane ruffling in porcine aortic endothelial cells, and suggest that synthesis of this lipid may be part of a signalling pathway leading to direct or indirect activation of the small GTP-binding protein Rac.

Multicentric evaluation of a new PT reagent based on recombinant human tissue factor and synthetic phospholipids

A new PT reagent based on recombinant human tissue factor and synthetic phospholipids (phosphatidyl choline and phosphatidyl serine) with defined fatty acid side chains was calibrated against BCT/253 and CRM 149R. A small but consistent bias in the International Sensitivity Index (ISI) value was obtained using either the human or rabbit brain reference material. ISI values were around 1.0 or slightly lower depending on the respective instrument. Mixing studies with factor deficient plasmas showed a high factor sensitivity especially for factor VII as compared to commercial rabbit brain or human placenta thromboplastin. In an international field trial the reagent was tested using fully or semi automated Electra coagulometers in 4 different laboratories. Results with normal samples were in excellent agreement among the different laboratories. Mean values were 10.9, 10.9, 11.0, 11.2 s with a range of 9.5 to 12.5 s. Results of males and females were not different. In patients with liver disease very similar PT activities were found as compared to sensitive rabbit brain or human placental thromboplastins. In normals and patients with oral anticoagulation INR values correlated very well against BCT (r = 0.98, regression line y = -0.07 + 0.9 x). The distribution of samples was linear over the whole range. In the comparison against sensitive rabbit brain thromboplastin or human placental thromboplastin similar correlations were found. In a few cases higher INR values were observed for the recombinant reagent especially in patients with intensive treatment. Factor assays in those patients showed at least the strong reduction of one vitamin K-dependent coagulation factor.(ABSTRACT TRUNCATED AT 250 WORDS)

External Ca effect on water permeability, regulatory volume decrease, and extracellular space in barnacle muscle cells

The effect of extracellular Ca2+ (Cao) on sarcolemmal hydraulic water permeability (L'p), regulatory volume decrease (RVD), and extracellular space (ECS) was studied in barnacle muscle cells. Absence or presence of Cao had no effect on L'p [0 Cao = 2.762 +/- 0.098 x 10(-5), and 11 mM Cao = 2.720 +/- 0.222 x 10(-5) cm.kg.s-1 x osmol x 1-kgH2O-1]. Likewise, cells exposed to anisosmotic media (for < 30 min) behaved as osmometers in 0 and 11 mM Cao, showing similar slopes and intercepts in van't Hoff plots. At longer incubation times, however, hyposmotic conditions promoted a Cao-dependent RVD. The relationship between Cao and the percentage of cells responding with RVD to a hyposmotic challenge was sigmoidal (half-maximal Cao = 4.83 mM). The mean rate of RVD (40 nl/min) was independent of the level of swelling in response to hyposmotic challenges. However, the magnitude of RVD increased with larger hyposmotic challenges. Both the presence of Cao and hypotonicity reduced the "apparent" ECS by 47 +/- 6 and 39 +/- 6%, respectively. Three-dimensional reconstruction of autoradiographs of the cells was made to interpret these results.

Fast-responding, fibre-optic based sensing system for the volatile anaesthetic halothane, using an ultraviolet absorption technique and a fluorescent film

An improved version of a fast-responding sensing system for the widely used volatile anaesthetic halothane (2-bromo-2-iodo-1,1,1-trifluoroethane) is described. The concentration of halothane is determined using an ultraviolet radiation (UV) absorption technique. Ultraviolet radiation at 230 nm is conveyed by a silica optical fibre to a gas flow-through cell containing the halothane, and the intensity of the UV reaching the other side of the cell is measured using a fluorescent polymer film. This paper describes the development of an efficient fluorescent polymer film for the sensor based on poly(ethylene glycol) containing two fluorophores (2,5-diphenyloxazole and tris[4,4,4-trifluoro-1-(2-thienyl)butane- 1,3-diono]europium(III)). The film fluoresces strongly with a red line spectrum when excited in the range from about 200 to 380 nm. There is evidence of direct energy transfer between the two fluorophores. A similar effect is observed in films prepared from Carbowax 20M and the europium chelate. An advantage of this approach is that the fluorescent radiation can be transmitted back to a silicon photo-detector using an inexpensive polymer optical fibre bundle. Two experimental sensor systems for halothane are described and the results show that, although the response does not obey the Beer-Lambert law, a reliable system for determining halothane can be constructed, which operates over the medically important range 0-3%. This paper also describes how the signal-to-noise ratio of the system can be improved by using the long fluorescence lifetime of the film.(ABSTRACT TRUNCATED AT 250 WORDS)