Understanding veterinarians' prescribing decisions on antibiotic dry cow therapy.

In the United Kingdom, blanket antibiotic dry cow therapy (BDCT) is commonly prescribed. An alternate strategy is selective dry cow therapy (SDCT) whereby a teat sealant is given instead of an antibiotic to cows with a low probability of infection. Switching from BDCT to SDCT can significantly reduce antibiotic use. The aims of this study were to explore how veterinarians (vets) rationalized their prescribing decisions for mammary treatments at drying off, and the barriers and motivators they perceived to implementing SDCT. Face-to-face interviews were conducted with 20 purposively recruited vets from 6 practices in England, United Kingdom. The data were analyzed qualitatively using an inductive thematic analysis. The majority of participants stated a personal preference for SDCT because it constitutes more responsible antibiotic use. On the majority of farms, the prescribing decision was taken by a senior veterinarian and BDCT was prescribed. Less experienced vets expressed a desire to be more involved in the decision-making process. The first theme, prioritizing responsible antimicrobial prescribing, encapsulated the difficulties vets expressed engaging with farmers, conflicts of interest, and vets' determination to take action. The second theme, the effect of a vet's experience on their ability to influence farmers, focused on the specific challenges faced by less experienced vets and the importance of vets being both trusted by farmers and being knowledgeable. The third theme, vets' perceptions about the risk and complexity of implementing SDCT, revealed markedly different levels of concern and fears about adverse outcomes with teat sealants versus antibiotics. The results also showed differences in perceptions about how difficult SDCT is to implement in practice. The last theme, vets' suggestions for facilitating the introduction of SDCT, was wide ranging and provided useful insight from a veterinary perspective into ways to facilitate SDCT. Initiatives that seek to alter vets' perceptions of the risks associated with switching to using SDCT are likely to prove useful in facilitating change. Our results also suggest that it is vital for senior vets to take a leading role in facilitating farms to implement SDCT. Less experienced colleagues may benefit from more help from senior vets to gain the trust of farmers and to become involved more quickly in herd-level preventive medicine. Vets must work together and take a united approach to reduce antimicrobial use.

Methane in aquifers and alluvium overlying a coal seam gas region: Gas concentrations and isotopic differentiation.

The detection and attribution of methane in aquifers overlying oil and gas reservoirs has recently gained increasing attention internationally. The Surat Basin, in the Great Artesian Basin (GAB), Australia, hosts a coal seam gas (CSG) reservoir, with feedlots, town water supply, mines and agriculture that extract groundwater from aquifers that underly and overly the gas reservoir. This study aimed to use a multi-isotopic approach to differentiate biogenic methane generated in situ in GAB aquifers and the Condamine Alluvium, from the biogenic CSG produced from the underlying Walloon Coal Measures reservoir, to understand if gas had migrated or not. Dissolved methane (0.001 to 160 mg/l) and total methane concentrations (up to 91,818 ppmv) were measured using closed sampling methods and were higher than from open direct fill sampling (<0.001 to 25.4 mg/l), especially in gassy bores that contain dissolved methane above 10 to 13 mg/l. The CSG production waters and a gassy overlying aquifer bore had the most depleted water isotopes, and also the most enriched δ13C-DIC indicating strong methanogenesis. The majority of aquifers have isotopic signatures (δ13C-DIC, CH4 and CO2) indicating in situ methane production by primary CO2 reduction or fermentation, distinct from secondary microbial CO2 reduction in the CSG reservoir. Fractionation factors support methane production mainly via CO2 reduction, with fermentation in a subset of aquifer samples. The gas wetness parameters (636 to 20,000) are consistent with mainly microbial gases, with low dissolved ethane (max 0.04 mg/l). The majority of aquifer and alluvium samples in this study are consistent with in situ methane production, not migration, however in several gassy bores the methane source could not be clearly identified. This study is broadly applicable to understanding methane sources in aquifers overlying CSG reservoirs.

The adsorption and self-assembly of mixtures of alkylbenzene sulfonate isomers and the role of divalent electrolyte.

In this paper, the role of the different structural isomers of the anionic surfactant sodium para-dodecyl benzene sulfonate, LAS, on surface adsorption and solution self-assembly has been studied. Using a combination of neutron reflectivity, NR, and small angle neutron scattering, SANS, the effect of mixing an isomer with a short symmetric hydrocarbon chain with one which has an asymmetric hydrocarbon chain on both the equilibrium surface adsorption behavior and the solution microstructure of the mixtures, both in the presence and absence of a divalent cation (Ca(2+)), has been investigated. In the absence of electrolyte, the LAS isomer mixtures form small charged globular micelles throughout the composition range studied. The micelle aggregation number increases with the increase in the asymmetric isomer content, reflecting an increase in the packing efficiency within the micelle. The addition of calcium ions promotes the formation of planar aggregates, as multilamellar vesicles, but only when the symmetric LAS isomer is the major component of the mixture. At a surfactant concentration just above the critical micelle concentration, CMC, and in the absence of electrolyte, the variation in the surface composition is close to the solution composition. Regular solution theory, RST, calculations show that this variation is also close to what is expected for ideal mixing. The addition of Ca(2+) ions induces a different surface behavior, resulting in the formation of multilayer structures at the interface throughout the entire composition range.

The development and validation of the Misophonia response scale.

OBJECTIVE: Most current Misophonia scales are not validated, do not include both emotional and physiological responses to triggers, and/or focus only on auditory triggers. This research aimed to develop and validate a measure of the magnitude of the Misophonic response that addressed these omissions. METHOD: Three studies were carried out with individuals with self-diagnosed Misophonia. In study 1, expert opinion and participants commented on initial items to determine both face and content validity. In study 2, scale structure, reliability, and convergent and discriminant validity were determined using correlations, principal component analysis (PCA), and reliability analysis. In study 3, factor structure was confirmed in another sample of participants using confirmatory factor analysis (CFA). RESULTS: The final 22-item scale assesses the magnitude of responses to triggers across any sensory modality. There are three subscales (emotional, physiological, and participation in life), with three additional items measuring frequency of triggers, avoidance of triggers, and time taken to recover from the triggers. The final scale showed suitable discriminant and convergent validity, with good internal consistency (Cronbach's alphas range 0.77 to 0.89). The three-component solution extracted using PCA explained 53.97% of variance, with all items loading between 0.45 and 0.84. The structure was confirmed with CFA (χ2 = 269.01, p < .001; CFI = 0.96; TLI = 0.96 and RMSEA = 0.045 (CI 0.037-0.053). CONCLUSION: The Misophonia Response Scale, which is valid and reliable, will facilitate understanding of Misophonia as it is short and easy to use for self-report in research.

Surface and solution properties of anionic/nonionic surfactant mixtures of alkylbenzene sulfonate and triethyleneglycol decyl ether.

The surface adsorption behavior and the solution microstructure of mixtures of the C(6) isomer of anionic surfactant sodium para-dodecyl benzene sulfonate, ABS, with nonionic surfactant monodecyl triethyleneglycol ether, C(10)E(3,) have been investigated using a combination of neutron reflectivity, NR, and small-angle neutron scattering, SANS. In solution, the mixing of C(10)E(3) and ABS results in the formation of small globular micelles over most of the composition range (100:0 to 20:80 ABS/C(10)E(3)). Planar aggregates (lamellar or unilamellar vesicles, ULV) are observed for solution compositions rich in the nonionic surfactant (>80 mol % nonionic). Prior to the transition to planar aggregates, the micelle aggregation number increases with increasing nonionic composition. The lamellar-phase region is preceded by a narrow range of composition over which mixtures of micelles and small unilamellar vesicles coexist. The variation in surface absorption behavior with solution composition shows a strong surface partitioning of the more surface-active component, C(10)E(3). This pronounced departure from ideal mixing is not readily explained by existing surfactant mixing theories. In the presence of Ca(2+) ions, a more complex evolution of solution phase behavior with solution composition is observed. The lamellar-phase region occurs over a broader range of solution compositions at the expense of the small-vesicle phase. The phase boundaries are shifted to lower nonionic compositions, and the extent to which the solution-phase diagrams are modified increases with increasing calcium ion concentration. The SANS data for the large planar aggregates are consistent with large polydisperse flexible unilamellar vesicles. In the presence of Ca(2+) ions, the surface adsorption patterns become more consistent with ideal mixing in the nonionic-rich region of the surface-phase diagram. However, in the ABS-rich regions the surface behavior is more complex because of the spontaneous formation of more complex surface microstructures (bilayers to multilayers). Both in water and in the presence of Ca(2+) ions the variations in the surface adsorption behavior and in the solution mesophase structure do not appear to be closely correlated.

The in vivo relationship between cross-sectional area and CT dose index in abdominal multidetector CT with automatic exposure control.

The relationship between patient cross-sectional area and both volume CT dose index (CTDI) and dose length product was explored for abdominal CT in vivo, using a 16 multidetector row CT (MDCT) scanner with automatic exposure control. During a year-long retrospective survey of patients with MDCT for symptoms of abdominal sepsis, cross-sectional areas were estimated using customised ellipses at the level of the middle of vertebra L3. The relationship between cross-sectional area and the exposure parameters was explored. Scans were performed using a LightSpeed 16 (GE Healthcare Medical Systems, Milwaukee, WI) operated with tube current modulation. From a survey of 94 patients it was found that the CTDI increased with the increase in patient cross-sectional area. The relationship was logarithmic rather than linear, with a least-squares fit to the data (R(2) = 0.80). For abdominal CT the cross-sectional area gave a measure of patient size based on the region of the body to be exposed. Exposure parameters increased with increasing cross-sectional area and the greater radiation exposure of larger patients was partly a consequence of their size. Given increasing obesity levels we believe that cross-sectional area and scan length should be added to future dose surveys, allowing patient size to be considered as a factor of relevance when examining population doses.

Microbiology insights into boosting salivary defences through the use of enzymes and proteins.

OBJECTIVES: To assess the effects of enzymes and proteins in toothpastes to boost salivary defences and reduce oral bacteria growth and viability. METHODS: An in vitro study to measure levels of hypothiocyanite in saliva after treatment with a toothpaste containing enzymes and proteins (colorimetric assay). A randomised, crossover in vivo study measuring, with biochemical assays, the effect of a toothpaste containing enzymes and proteins on the levels of hydrogen peroxide and lysozyme in saliva. In vitro studies to measure, using fluorescent dyes, the effects of enzymes and proteins on bacterial membrane integrity. In vitro microbiology studies measuring the effects of enzymes and proteins on planktonic bacterial growth, in vitro studies in single and multispecies biofilms measuring the effect of toothpaste with enzymes and proteins compared to control toothpaste. RESULTS: Levels of hypothiocyanite, hydrogen peroxide and lysozyme are boosted after application of a toothpaste containing enzymes and proteins. The enzymes and proteins adversely affect the bacterial membrane integrity in Streptococcus mutans and growth of planktonic S. mutans and Fusobacterium nucleatum. In a single species biofilm model the viability of S. mutans was significantly reduced and in a 7 species biofilm model bacterial viability was reduced for a biofilm grown on a pellicle pre-treated with toothpaste containing enzymes and proteins. CONCLUSIONS: The use of a toothpaste containing enzymes and proteins can boost the natural salivary defences by increasing the levels of lysozyme and hydrogen peroxide in vivo and hypothiocyanite in vitro and reduce the growth and viability of oral bacteria in microbiological models. CLINICAL SIGNIFICANCE: The subtle effects reported here of enzymes and proteins in toothpastes on oral bacteria are consistent with both the gum health benefits reported for such toothpastes containing enzymes and proteins by Daly [1] and Pedersen [2] and the rebalancing of the oral microbiome reported by Adams [3].

The influence of hydrogeological disturbance and mining on coal seam microbial communities.

The microbial communities present in two underground coal mines in the Bowen Basin, Queensland, Australia, were investigated to deduce the effect of pumping and mining on subsurface methanogens and methanotrophs. The micro-organisms in pumped water from the actively mined areas, as well as, pre- and post-mining formation waters were analyzed using 16S rRNA gene amplicon sequencing. The methane stable isotope composition of Bowen Basin coal seam indicates that methanogenesis has occurred in the geological past. More recently at the mine site, changing groundwater flow dynamics and the introduction of oxygen in the subsurface has increased microbial biomass and diversity. Consistent with microbial communities found in other coal seam environments, pumped coal mine waters from the subsurface were dominated by bacteria belonging to the genera Pseudomonas and the family Rhodocyclaceae. These environments and bacterial communities supported a methanogen population, including Methanobacteriaceae, Methanococcaceae and Methanosaeta. However, one of the most ubiquitous micro-organisms in anoxic coal mine waters belonged to the family 'Candidatus Methanoperedenaceae'. As the Archaeal family 'Candidatus Methanoperedenaceae' has not been extensively defined, the one studied species in the family is capable of anaerobic methane oxidation coupled to nitrate reduction. This introduces the possibility that a methane cycle between archaeal methanogenesis and methanotrophy may exist in the anoxic waters of the coal seam after hydrogeological disturbance.

Targeting neuronal nitric oxide synthase with gene transfer to modulate cardiac autonomic function.

Microdomains of neuronal nitric oxide synthase (nNOS) are spatially localised within both autonomic neurons innervating the heart and post-junctional myocytes. This review examines the use of gene transfer to investigate the role of nNOS in cardiac autonomic control. Furthermore, it explores techniques that may be used to improve upon gene delivery to the cardiac autonomic nervous system, potentially allowing more specific delivery of genes to the target neurons/myocytes. This may involve modification of the tropism of the adenoviral vector, or the use of alternative viral and non-viral gene delivery mechanisms to minimise potential immune responses in the host. Here we show that adenoviral vectors provide an efficient method of gene delivery to cardiac-neural tissue. Functionally, adenovirus-nNOS can increase cardiac vagal responsiveness by facilitating cholinergic neurotransmission and decrease beta-adrenergic excitability. Whether gene transfer remains the preferred strategy for targeting cardiac autonomic impairment will depend on site-specific promoters eliciting sustained gene expression that results in restoration of physiological function.

Release and interconversion of P2 receptor agonists by human osteoblast-like cells.

Nucleotides, acting as agonists at P2 receptors, are important extracellular signaling molecules in many tissues. In bone they affect both bone-forming osteoblast and bone-resorbing osteoclast cell activity. The presence of nucleotides in the extracellular microenvironment is largely determined by their release from cells and metabolism by ecto-enzymes, both of which have scarcely been studied in bone. We have investigated adenosine 5'-triphosphate (ATP) release from SaOS-2 osteoblastic cells and the activities of cell surface ecto-enzymes on ATP metabolism. ATP, but not LDH, was detected in SaOS-2 cell conditioned medium, suggesting these cells were actively releasing ATP. Introduction of ADP resulted in increased ATP concentrations in the medium, which was found not to be receptor mediated. Nucleotide inhibition and substrate specificity studies revealed an ecto-nucleoside diphosphokinase (ecto-NDPK) was responsible for the ADP-->ATP conversion; PCR and immunocytochemistry confirmed its presence. Analysis of ATP metabolism over time demonstrated overall ATP degradation was increased by inhibiting ecto-NDPK activity; confirming that the combined action of multiple osteoblast-expressed ecto-enzymes affected extracellular nucleotide concentration. The data establish the coexistence of ATP-consuming, and for the first time, ATP-generating activities on the osteoblast cell surface, the discovery of which has significant implications for studies involving P2 receptor subtypes in bone.

A comparative study of evaluation of radiographs, CT and 3D reformatted CT in facial trauma: what is the role of 3D?

A panel of 17 trainee maxillofacial surgeons viewed 23 cases of facial trauma, demonstrated on radiographs, axial CT images and three-dimensional (3D) reformatted CT images in a standardized viewing format under standard conditions. Their diagnostic interpretation, extraction of information relevant to surgical management and subjective evaluation of each modality were recorded by standard questionnaire and compared with a gold standard evaluation by a consultant radiologist and surgeon reading based on results of clinical management. There were clear and measurable differences in the viewers' evaluations of radiographs, CT and 3D reformatted images. Overall, surgeons showed more accurate diagnostic reading of radiographs and 3D reformatted images. This was in contrast to their subjective assessment of the clinical value of each modality, which showed a strong preference for 3D over all other techniques and for CT over radiographs. However the perceived benefit of axial CT images over radiographs was not reproduced on objective testing in this group; surgeons appear to perform less well in interpreting CT images than their subjective response to the modality would suggest. This work has supported the view that surgeons value 3D imaging as a front-line tool in the evaluation and management of selected cases of acute facial trauma. We have demonstrated that the perceived benefits of 3D reformatted CT to surgeons appear real.

Peripheral pre-synaptic pathway reduces the heart rate response to sympathetic activation following exercise training: role of NO.

OBJECTIVES: We tested the hypothesis that the attenuated heart rate (HR) response to sympathetic activation following swim training in the guinea pig (Cavia porcellus) results from a peripheral modulation of pacemaking by nitric oxide (NO). METHODS: Nitric oxide synthase (NOS) inhibition on the increase in heart rate with sympathetic nerve stimulation (SNS) was investigated in the isolated guinea pig double atrial/right stellate ganglion preparation from exercise trained (6-weeks swimming, n=20) and sedentary animals (n=20). Western blot analysis for neuronal nitric oxide synthase (nNOS) was performed on the stellate ganglion from both groups. RESULTS: Relative to the control group, the exercise group demonstrated typical exercise adaptations of increased ventricular weight/body weight ratio, enhanced skeletal muscle citrate synthase activity and higher concentrations of [3H]ouabain binding sites in both skeletal and cardiac tissue (P<0.05). The increase in heart rate (bpm) with SNS significantly decreased in the exercise group (n=16) compared to the sedentary group (n=16) from 30+/-5 to 17+/-3 bpm at 1 Hz; 67+/-7 to 47+/-4 bpm at 3 Hz; 85+/-9 to 63+/-4 bpm at 5 Hz and 101+/-9 to 78+/-5 bpm at 7 Hz stimulation (P<0.05). The increase in heart rate with cumulative doses (0.1-10 microM) or a single dose (0.1 microM) of bath-applied norepinephrine expressed as the effective doses at which the HR response was 50% of the maximum response (EC50) were similar in both exercise (EC50 -6.08+/-0.16 M, n=8) and sedentary groups (EC50 -6.18+/-0.07 M, n=7). Trained animals had significantly more nNOS protein in left stellate ganglion compared to the sedentary group. In the exercise group, the non-isoform selective NOS inhibitor, N-omega nitro-L-arginine (L-NA, 100 microM) caused a small but significant increase in the heart rate response to SNS. However, the positive chronotropic response to sympathetic nerve stimulation remained significantly attenuated in the exercise group compared to the sedentary group during NOS inhibition (P<0.05). CONCLUSIONS: Our results indicate that there is a significant peripheral pre-synaptic component reducing the HR response to sympathetic activation following training, although NO does not play a dominant role in this response.

Ceruloplasmin, transferrin and apotransferrin facilitate iron release from human liver cells.

The rate of iron release from HepG2 liver cells was increased not only by extracellular apotransferrin, but also by diferric transferrin, in a non-additive, concentration-dependent manner and to a similar magnitude. This suggests that rapid equilibration between receptor-mediated uptake and the release process determines net iron retention by the liver. Release was also accelerated by ceruloplasmin; most importantly, the effect of this protein was greatest when iron release was occurring rapidly, stimulated by apotransferrin, or under conditions of limited oxygen. Thus iron release involves both apotransferrin and ferrotransferrin, with ceruloplasmin playing a role in tissues with limited oxygen supply, as in the liver in vivo.

Body composition in myelomeningocele.

Body composition and measures of obesity were evaluated in 59 subjects with myelomeningocele (MMC), aged 0.3-29 y, by anthropometry and measures of body cell mass (BCM) and intra- and extracellular water (ICW and ECW), derived from total body potassium and deuterium-isotope dilution; these results were compared with reference data. Body composition was normal in preambulatory children with MMC. Beyond ages 3-4 y there was significant depletion of BCM and total body water, with maldistribution of water (increased ECW and decreased ICW) and increased percentage body fat above that expected for age and sex. These findings were more pronounced in females and in those with high lesions, and were less pronounced in those who remained ambulatory. These changes may result in metabolic and nutritional maladaption during stress. The relation of BCM, total body water depletion and increased ECW to decreasing ambulatory activity suggests that early nutritional and mobility programs warrant further study.

Nephropathy in the mature pig after the irradiation of a single kidney: a comparison with the immature pig.

The right kidney of 11 mature 10-month-old Large White female pigs was irradiated with single doses of 9.8-14.0 Gy of 60Co gamma rays. Individual kidney glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) were measured using 99mTc-DTPA and 131I-hippuran renography for periods up to 24 weeks after irradiation. Renal function was assessed either as a functional index, FI (FI = irradiated/unirradiated kidney function), or as the individual kidney GFR and ERPF. The radiation-induced changes after the irradiation of a single kidney (unilaterally irradiated--UI) of mature pigs were compared with those previously observed in 14-week-old immature pigs. Irradiation resulted in a dose-dependent reduction in the FI for both GFR and ERPF. However, these reductions were significantly less than those previously seen in immature pigs. Within 2 weeks of irradiation GFR increased in both the irradiated and the unirradiated kidneys in each animal, compared with unirradiated age-matched control kidneys. No marked changes in renal hemodynamics were seen in mature animals after a single dose of 9.8 Gy. This was in marked contrast to the pronounced reduction in the GFR and ERPF in the irradiated kidney previously observed in immature animals irradiated with an equivalent single dose of X rays. After higher doses, the irradiated kidney in mature pigs showed a dose-dependent reduction in GFR and ERPF. However, the extent of this reduction was significantly less than that seen in immature animals. There was no apparent difference in the response of the unirradiated kidneys in mature or immature pigs. The ED50 values, based on a probit fit to the data for the proportion of functional tests in which the irradiated kidney showed a greater than or equal to 50% reduction in GFR or ERPF, were higher in the mature animals; for example for ERPF the ED50 values were 11.76 +/- 0.28 Gy and 7.67 +/- 0.34 Gy for mature and immature animals, respectively. Thus, the UI kidney in mature pigs appears to be less radiosensitive than the UI kidney in immature animals.

Radiation-induced changes in glomerular and tubular cell kinetics and morphology following irradiation of a single kidney in the pig.

PURPOSE: Radiation-induced changes in glomerular and tubular cell kinetics and morphology following irradiation of a single pig kidney were assessed. METHODS AND MATERIALS: The right kidney of 13 adult female Large White pigs was irradiated with a single dose of 9.8 Gy gamma rays. Animals were serially killed between 2 and 24 weeks postirradiation (PI); 1 h prior to postmortem each pig received 500 mg bromodeoxyuridine (BrdUrd). At postmortem, both kidneys were removed and tissue taken to prepare cell suspensions. The labeling index (LI) of these suspensions was measured using flow cytometry; in vivo BrdUrd incorporation in glomerular and tubular cells was determined immunohistochemically. The kidneys were also assessed histologically. RESULTS: Irradiation of the right kidney alone resulted in a significant increase in renal cell LI in both the irradiated and the contralateral unirradiated kidney within 2 weeks of irradiation; peak values of 1.57 +/- 0.32% and 1.04 +/- 0.13%, respectively, were seen 4 weeks PI, significantly greater (P < 0.001) than the preirradiation value of 0.18 +/- 0.01%. The LI values then declined with time, but remained greater than those seen prior to irradiation. A similar pattern of response was determined from counts of labeled glomerular and tubular cells identified immunohistochemically. The increase in labeled glomerular cells was seen 2 weeks PI, whereas that for the tubular cells did not occur until 4 weeks PI. The irradiated kidney exhibited diffuse, progressive glomerular alterations. In contrast, tubular damage was focal; the irradiated kidney also exhibited a prominent vasculopathy, involving arteriolar and peripheral interlobular artery thickening. The contralateral unirradiated kidney appeared unchanged. CONCLUSION: These findings confirm the hypothesis that the morphologic and kinetic responses observed after irradiation of a single kidney are similar to those observed after irradiation of both kidneys. Renal irradiation results in significant alterations in glomerular and tubular cell proliferation and morphology within 2-4 weeks of irradiation; glomerular changes appear predominant.

Functional recovery in the irradiated kidney following removal of the contralateral unirradiated kidney.

The right kidneys of seven Large White female pigs, approximately 14 weeks of age, were irradiated with single doses of 7-12.6 Gy of 250 kV X-rays. Sequential measurements of individual kidney glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) were carried out using 99mTc-DTPA and [131I]hippuran renography for time periods up to 24 weeks after irradiation. From this data, kidneys receiving a dose of 7 Gy were found to be functioning (F), while kidneys which received greater than or equal to 8.8 Gy were assessed as having no significant function (NF). When the pigs were approximately 10 months of age the contralateral unirradiated kidney was removed; the left kidney of three age-matched unirradiated pigs was also removed. The response of the right kidney to unilateral nephrectomy (UN) in these animals was assessed in terms of changes in haemodynamics (i.e. GFR and ERPF) for periods up to 24 weeks after UN. At post-mortem, the length and weight of the remaining kidney was measured. A marked increase in renal length was observed in irradiated kidneys following UN. In addition, the weights of irradiated kidneys following UN were greater than those of irradiated kidneys in age-matched pigs where the unirradiated kidney had not been removed. Four weeks after UN there was a pronounced increase in GFR and, in particular, ERPF in previously NF irradiated kidneys. The mean increase in these parameters, measured at the end of the follow-up period, when compared with the pre-surgery values, was 350.1 +/- 84.3 and 781.8 +/- 151.0% respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

The response of the pig kidney to the combined effects of cisplatin and unilateral renal irradiation.

Seven mature Large White female pigs, approximately 10 months of age received a single dose of cis-dichlorodiammineplatinum(II), c-DDP (2.5 mg/kg body weight). Prior to, and 4 weeks after c-DDP administration, individual kidney glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) were measured by [99mTc]DTPA and [131I]hippuran renography. Of the 5 pigs surviving the c-DDP treatment most exhibited a reduction in both GFR and ERPF; the mean reduction in GFR (36.2 +/- 18.9%) was more pronounced than that for ERPF (12.6 +/- 19.4%). However, the difference in the severity of the impairment in these two parameters was not significant (p greater than 0.55). Haematocrit, haemoglobin and red blood cell counts were markedly reduced 14 days after c-DDP infusion, and despite some recovery evident 21 days after treatment, all three haematological parameters were still reduced 28 days after c-DDP administration. The right kidneys of these 5 animals, plus 5 pigs which did not receive c-DDP, were irradiated with a single dose of 11.9 Gy of 60Co gamma-rays. Individual kidney GFR and ERPF was routinely measured up to 24 weeks after irradiation. Pigs in which only the right kidney was irradiated showed a marked increase in both GFR and ERPF values 2 weeks after irradiation. This was followed by a decline in function with a reduction of 50% in terms of ERPF 16 weeks after irradiation. Values then showed some evidence of a recovery in function. There was a concomitant compensatory response by the contralateral unirradiated kidney.(ABSTRACT TRUNCATED AT 250 WORDS)