Description of serum symmetric dimethylarginine concentration and of urinary SDS-AGE pattern in dogs with ACTH dependent hyperadrenocorticism

Serum symmetric dimethylarginine (SDMA) and patterns of urinary protein separated by sodium dodecyl sulfate agarose gel electrophoresis (SDS-AGE) have not been investigated as biomarkers in dogs with ACTH-dependent hyperadrenocorticism (ADHAC). This exploratory prospective study aimed to evaluate SDMA, serum creatinine (sCR), and SDS-AGE in dogs with ADHAC with and without proteinuria (ADHAC-P and ADHAC-nP, respectively). Thirty-five pet dogs classified as ADHAC-P (n=16), ADHAC-nP (n=6) and healthy (n=13) were included. Renal biomarkers were evaluated in all dogs at diagnosis. Baseline concentration of SDMA was not significantly different between the three groups (P = 0.15) whereas sCr was significantly lower in dogs in ADHAC dogs compared to healthy dogs (88.0 µmol/L [70.4-132.6; 79.2-114.4]) whether they had proteinuria or not (P = 0.014 and 0.002, respectively). However, baseline concentrations of sCr and SDMA were not significantly different between dogs with ADHAC-P dogs (SDMA, 8 µg/dL [5-12; 7-9]; sCr, 57.2 µmol/L [35.2-212.2; 52.8-92.4]) and ADHAC-nP dogs (SDMA, 8.5 µg/dL [7-13; 8-10]; sCr, 70.4 µmol/L [61.6-79.2; 61.6-70.4]) (P = 0.35 and P = 0.41, respectively). Proteinuria in dogs with ADHAC-P was mainly of glomerular origin (SDS-AGE pattern: glomerular in 10/16 dogs; mixed glomerular/tubular in four dogs). In our study, SDMA was neither significantly different in dogs with ADHAC whether they were proteinuric or not, nor between ADHAC and healthy dogs. Urinary electrophoresis provides additional information to the UPC and further investigations are needed to determine whether it may help identify dogs with ADHAC-P requiring specific antiproteinuric treatment.

Dose Coverage Variation Caused by Setup Uncertainties in VMAT-TBI Treatment

PURPOSE/OBJECTIVE(S)

Volumetric Modulated Arc Therapy Total Body Irradiation (VMAT TBI) offers several advantages over conventional TBI techniques, including reduced cost of the treatment room (a normal-sized vault versus a large shielded vault), increased patient comfort during treatment, lung sparing without the need for physical blocks, and a more homogeneous dose distribution. In VMAT-TBI treatment, plans at multiple isocenters are utilized to cover the entire body, and patients are positioned with the aid of image guidance. However, aligning the patient's entire body during setup can be challenging due to its pliability, and the setup time is heavily dependent on the tolerance allowed by the image guidance. Therefore, studying the variation in dose coverage caused by setup uncertainties in VMAT-TBI treatments can help optimize the clinical workflow and determine the optimal tolerance for patient positioning.

MATERIALS/METHODS

New plans were generated to simulate the uncertainties that occur during treatment setup for each patient. These plans were created by shifting the original VMAT TBI plans at the head, chest, abdomen (or pelvis) isocenters by 5mm and 1cm in the left-right (LR), inferior-superior (IS), and anterior-posterior (AP) directions, respectively. Dose DicomRT files were exported, and the dose change due to the shifts was analyzed. The statistical quantification of the percentage of the body that experienced a dose change of over 2%, 5%, and 10% of the prescription due to the shifts from the original plans was calculated for all patients. Histograms were generated, showing the percentage of body getting dose change of 1-2%, 2-3%, 3-5%, 5-7%, 7-10%, 10-15%.

RESULTS

The table below displays the percent volume receiving a dose change of 2%, 5%, and 10% of the prescription for a 5mm shift. Among the shift directions, the dose change is most sensitive in the IS direction, with similar impact observed the in LR and AP directions. Among different sites, the chest experiences the largest dose change, followed by the pelvis. For a 5mm shift in the IS direction, the average percent volume receiving a dose change of 2%, 5%, and 10% in the chest is 9.25%, 2.64%, and 0.27%, respectively. For a 1cm shift, the numbers are 12.23%, 6.75%, and 1.29%. In the pelvis (abdomen), these values are 9.03%, 1.67%, and 0.17% for a 5mm shift and 13.28%, 6.1%, and 0.85% for a 1cm shift. For head plans, the values are 2.72%, 0.9%, and 0.14% for a 5mm shift and 3.77%, 1.66%, and 0.53% for a 1cm shift.

CONCLUSION

Accurate alignment in the chest region is crucial in VMAT TBI treatment. Efforts should be made to minimize shifts over 1cm in the IS direction.

Short course of immune-suppressive doses of prednisolone, evaluated through a prospective double-masked placebo-controlled clinical trial in healthy Beagles, is associated with sustained modifications in renal, hydration, and electrolytic status

OBJECTIVE

To investigate the effects and duration of orally administered prednisolone on renal function evaluated by glomerular filtration rate (GFR) determination and creatinine (Cr) and symmetric dimethylarginine (SDMA) concentrations as well as on urinalysis, electrolytes, and hydric status in healthy dogs.

ANIMALS

14 healthy Beagles.

PROCEDURES

In this prospective double-masked placebo-controlled study, dogs were randomized after baseline evaluation to receive a 7-day course of either prednisolone (1.5 to 2.0 mg/kg, PO, q 12 h) or a placebo. A repeated-measure design was performed, each dog participating in 4 successive sampling sessions. Clinical data, systolic blood pressure, CBC, and biochemical analyses including serum SDMA concentration, GFR determination, urine output quantification, and complete urinalysis were performed for all dogs the day before (D0) and at the end of steroid administration (D7) as well as 2 weeks (D21) and 4 weeks (D35) after the end of treatment.

RESULTS

At D7, when compared with baseline, GFR increased significantly in treated dogs, whereas creatinine and SDMA concentrations decreased significantly. GFR and Cr but not SDMA modifications persisted significantly at D21. None of the variables differed significantly from baseline at D35. The OR of presenting an albumin band on urine electrophoresis was 2.4 times as high in treated versus control dogs (OR, 36; 95% CI, 1.8 to 719.4; P = 0.02).

CLINICAL RELEVANCE

A short-term course of immune-suppressive prednisolone treatment in healthy dogs leads to a sustained but reversible renal hyperfiltration state. Modification in electrolytic variables can affect the clinical interpretation of blood work in such patients.

P43 In vitro activity of cefiderocol and comparators against Gram-negative pathogens: ARTEMIS study in the UK

Objectives

Cefiderocol (CFDC) is a novel siderophore cephalosporin approved in Europe for the treatment of infections caused by aerobic Gram-negative (GN) bacteria in adults with limited treatment options. The aim of the ARTEMIS study was to evaluate the in vitro activity of CFDC and comparators against recent clinical isolates collected across five countries in Europe. Here we report susceptibility data from isolates collected in the UK.

Methods

From January to December 2020, GN clinical isolates were collected from hospitalized patients from all infection sites (excluding the urinary tract). Duplicate isolates of the same species from a single patient were excluded. As a prespecified target, each laboratory collected 75 isolates, with: 20 Klebsiella spp., 20 other Enterobacterales, 20 Pseudomonas aeruginosa and 15 Acinetobacter baumannii isolates expected to be included. CFDC susceptibility testing was conducted using disc diffusion (with 30 μg discs) on Mueller–Hinton agar and Sensititre^™ broth microdilution (BMD) panels [EUMDROXF; centrally tested at International Health Management Associates (IHMA)]. Susceptibility by disc diffusion was reported using zone diameter breakpoints (BPs) of ≥22 mm (or ≥17 mm for A. baumannii isolates, corresponding to MIC values below the pharmacokinetic/pharmacodynamic BPs of ≤2 mg/L). Comparator susceptibility was determined using custom research use only Sensititre^™ BMD panels (CMP2SHIH) according to the EUCAST method for BMD. Antimicrobial susceptibility was interpreted according to EUCAST clinical BPs (v.11 2021).

Results

In total, 517 isolates were collected from nine UK hospitals, of which: 308 (59.6%) were Enterobacterales [including 147 (28.4%) Klebsiella spp.], 148 (28.6%) were P. aeruginosa and 33 (6.4%) were A. baumannii. The most common sites of infection were bloodstream (n = 245; 47.4%), respiratory tract (n = 158; 30.6%) and skin (n = 59; 11.4%). A high percentage of Enterobacterales (90.2%), P. aeruginosa (96.6%) and A. baumannii (96.9%) isolates were susceptible to CFDC by disc diffusion. By central laboratory testing (MIC), 99.0% of Enterobacterales, 99.3% of P. aeruginosa and 93.9% of A. baumannii isolates were susceptible to CFDC. High susceptibility rates (>85%) were also observed for all comparator agents (Table 1). A total of 32/517 (6.2%) isolates were carbapenem resistant, the majority of which (22/32, 68.8%) were susceptible to CFDC by disc diffusion.

Conclusions

Among clinical GN isolates collected from UK hospitals in 2020, a high percentage (98.6%), including carbapenem-resistant isolates, were susceptible to CFDC by BMD. These data support the use of CFDC in patients with GN infections and limited treatment options. The differences identified between EUCAST disc diffusion and BMD using Sensititre^™ panels for CFDC highlight that disc diffusion underestimates Enterobacterales susceptibility to CFDC, which is mainly a result of the area of technical uncertainty (where isolates with MIC of 2 mg/L have a zone diameter of <22 mm and are characterized as resistant). This requires further investigation to explore whether the EUCAST zone diameter BP is optimal for CFDC disc testing.

Asymptomatic carriage of canine infectious respiratory disease complex pathogens among healthy dogs

OBJECTIVES

The objectives of this study were to determine the prevalence of canine infectious respiratory disease pathogens among asymptomatic client-owned dogs, and to compare the risks of asymptomatic pathogen carriage between client-owned dogs and dogs in an animal shelter.

MATERIALS AND METHODS

Pooled tonsillar, conjunctival and nasal cavity swabs from asymptomatic client-owned dogs (n=133) were tested using a real-time polymerase chain reaction canine respiratory panel. Identical samples from asymptomatic dogs in an animal shelter (n=295) were similarly tested for selected pathogens. Risk differences were calculated between client-owned dogs and shelter dogs for each of the respiratory pathogens included in the analyses.

RESULTS

A total of 15 of 133 (11.3%) asymptomatic client-owned dogs were positive for at least one pathogen in the complex. Seven dogs (6.1%) were positive for M. cynos, six (5.2%) were positive for B. bronchiseptica, two (1.7%) were positive for canine herpesvirus type 1 and two (1.7%) were positive for canine respiratory coronavirus. For all eight pathogens tested in both groups, the proportion of positive cases was higher among shelter dogs than among client-owned dogs. Shelter dogs had a higher risk for M. cynos (0.18, 95% confidence interval: 0.12 to 0.25), canine respiratory coronavirus (0.15, 95% confidence interval: 0.10 to 0.19), canine distemper virus (0.06, 95% confidence interval: 0.03 to 0.09), and canine pneumovirus (0.05, 95% confidence interval: 0.03 to 0.08) than client-owned dogs. Odds ratios for M. cynos (0.31, 95% confidence interval: 0.08 to 0.92) and canine respiratory coronavirus (0.05, 95% confidence interval: 0.01 to 0.18) were significantly different between client-owned and shelter dogs. In all cases except for canine herpesvirus type 1, dogs within the shelter population were observed to be at higher risk of exhibiting asymptomatic carriage of a respiratory pathogen as compared to client-owned dogs. The strength of this association was strongest for M. cynos and canine respiratory coronavirus.

CLINICAL SIGNIFICANCE

The risk of canine infectious respiratory disease pathogen exposure posed by asymptomatic client-owned dogs is poorly defined. This study also corroborates previous reports of high canine infectious respiratory disease prevalence among clinically healthy shelter dogs, and further determined that the overall prevalence of canine infectious respiratory disease pathogen carriage among clinically healthy client-owned dogs is low but is highest for the traditional pathogen B. bronchiseptica and the emerging pathogen M. cynos.

Urinary clusterin and cystatin B as biomarkers of tubular injury in dogs following envenomation by the European adder

Diagnosing acute kidney injury remains a challenge since the established renal biomarkers, serum creatinine (sCr) and symmetric dimethylarginine (SDMA) reflect glomerular function and not tubular injury. Sensitive tubular markers such as urinary clusterin (uClust) and cystatin B (uCysB) have been proposed to detect AKI at an earlier stage. Since envenomation by the European adder (Vipera berus berus) could serve as a spontaneous disease model of AKI we investigated these new biomarkers in affected dogs. Concentrations of uClust and uCysB as well as sCr and SDMA were analyzed retrospectively in stored samples from 26 dogs with snake envenomation and 13 healthy controls. Higher concentrations of uClust (P < 0.012) and uCysB (P < 0.001) were observed in the snake-envenomed group. Normalization of uClust and uCysB to urinary creatinine did not alter the results. No differences were observed in sCr and SDMA between the snake-envenomed group and the healthy control group. Spearman rank correlation analysis revealed a strong association of uClust with uCysB in the snake-envenomed dogs (r = 0.75 P < 0.001) but not in the healthy controls. The high percentage of snake-envenomed dogs with increased uClust and uCysB concentrations in the absence of increased sCr and SDMA suggests renal tubular injury in the affected dogs. Larger prospective case-controlled studies are warranted to evaluate the clinical utility and prognostic value of these biomarkers.

Antibiotic use is associated with resistance of environmental organisms in a teaching hospital

An intensive care unit (ICU), acute stroke unit (ASU) and medical day bed unit (MDBU) underwent a standardized four-month environmental screening programme. The aim was to examine environmental organisms from these wards and compare bacterial resistances in association with antimicrobial usage. Hand-touch and other sites were screened using commercial dip-slides, and staff were asked to provide fingertip cultures. Patient blood isolates were retained throughout the study. Organisms were quantitatively and qualitatively assessed including antimicrobial susceptibility testing. Antibiotic consumption data in defined daily doses/1000 patient-days were obtained for each unit for the previous year. Two hundred and seventy-six staphylococci and 67 Gram-negative bacilli were recovered. Antibiotic resistance was significantly associated with individual wards for staphylococci (P<0.0001) and coliforms (P=0.04), and trends were also demonstrated for other Gram-negative organisms (P=0.06) despite fewer numbers. Antibiotic consumption on the ICU was six-fold higher than on the ASU and MDBU. Associations were found between consumption of selected antibiotic groups and corresponding resistances among staphylococci and Gram-negative bacilli. Antibacterial resistance was the only significant difference between environmental bacteria from different wards, and appeared to reflect prescribing pressure. Visual inspection of a ward may not provide a reliable guide regarding the presence of multi-resistant organisms in the hospital environment or the potential risk of infection. These findings have implications for local antibiotic policies, infection control and cleaning schedules.

Recombinant AAV-mediated delivery of a tet-inducible reporter gene to the rat retina

Viral delivery of neurotrophins or other therapeutic genes is an attractive option for treating retinal degeneration. Regulated expression of these genes in the retina is needed to aid in dose delivery and to promote safety. To evaluate whether tetracycline (tet)-inducible transgenes encapsidated in recombinant adeno-associated viruses (rAAV) can provide controlled gene expression in vitro and in the rat retina, two viruses were constructed: a silencer/activator vector and an inducible doxycycline (dox)-responsive GFP vector. Combinations of these two viruses were subretinally injected into wild-type rats and dox was orally administered through the drinking water. Retinal GFP expression was monitored in vivo with a noninvasive fluorescence imaging method. Eyes were also examined by histology, Western analysis, and electroretinography. Subretinal injection of rAAV efficiently delivers inducible genes to both photoreceptors and retinal pigment epithelial cells. GFP expression was initially observed 1 week postinduction, and GFP protein was undetectable after removal of dox. In uninduced animals, GFP expression was negligible. The dox dosage was varied in vivo and showed a correlation to the level of GFP expression. Thus, transduction of retinal cells with tet-inducible vectors allows for tight regulation of gene expression.

Evaluation of the clinical efficacy of marbofloxacin (Zeniquin) tablets for the treatment of canine pyoderma: an open clinical trial

The efficacy and field safety of marbofloxacin (Zeniquin) for the treatment of superficial and deep bacterial pyoderma were evaluated. Seventy-two dogs were treated with 2.75 mg kg-1 of marbofloxacin orally once daily for 21 or 28 days. Sixty-two dogs (86%) had superficial pyoderma and 10 (14%) had deep pyoderma. A history of prior pyoderma was reported in 39/72 dogs. Pretreatment aerobic bacteriologic cultures of skin lesions were performed in 47 cases and the predominant pathogen isolated was Staphylococcus intermedius. Treatment was successful in 62/72 (86.1%) dogs, improvement was noted in 6/72 (8.3%) dogs and treatment failed in 4/72 (5.6%) dogs. Adverse effects associated with treatment included listlessness, anorexia, vomiting, soft stool, flatulence and polydipsia; these adverse effects were seen in only 6/81 dogs. Marbofloxacin was safe and effective for the treatment of superficial and deep pyoderma in dogs at the dosage used in this study.

Two animal models of retinal degeneration are rescued by recombinant adeno-associated virus-mediated production of FGF-5 and FGF-18

The goal of these experiments was to evaluate the potential of the fibroblast growth factor family members FGF-5 and FGF-18 to rescue photoreceptors from cell death in retinal degenerative disease. Two strains of transgenic rats, expressing either a P23H or an S334ter rhodopsin mutation, were used as model systems. The neurotrophic growth factors were delivered by subretinal injection of adeno-associated virus vectors, driving expression of the genes with a constitutive CMV promoter. Morphological and functional analyses were performed to determine whether FGF-5 or FGF-18 overexpression could ameliorate cell death in the retina. Immunocytochemistry was used to determine the cellular sites of expression of the factors and to test for up-regulation of FGF receptors due to injection. Significant rescue from photoreceptor cell death was found after injections of vectors expressing either FGF-5 or FGF-18 in the animal models. Increased survival of photoreceptors did not produce a significant increase in electroretinographic responses, however, reflecting either trauma due to the surgery or a suppression of signaling due to expression of proteins. Three weeks after injections, both growth factors were localized to the inner and outer segments of photoreceptors, and the receptors FGFR1 and FGFR2 were also found to be up-regulated in these regions. No visible pathological changes were seen in the FGF-5- or FGF-18-treated eyes. These results indicate that the delivery of either FGF-5 or FGF-18 with adeno-associated virus protects photoreceptors from apoptosis in transgenic rat models of retinitis pigmentosa and that the rescue is probably mediated by conventional receptor tyrosine kinase pathways in photoreceptors.

The sequence of the human genome

A 2.91-billion base pair (bp) consensus sequence of the euchromatic portion of the human genome was generated by the whole-genome shotgun sequencing method. The 14.8-billion bp DNA sequence was generated over 9 months from 27,271,853 high-quality sequence reads (5.11-fold coverage of the genome) from both ends of plasmid clones made from the DNA of five individuals. Two assembly strategies-a whole-genome assembly and a regional chromosome assembly-were used, each combining sequence data from Celera and the publicly funded genome effort. The public data were shredded into 550-bp segments to create a 2.9-fold coverage of those genome regions that had been sequenced, without including biases inherent in the cloning and assembly procedure used by the publicly funded group. This brought the effective coverage in the assemblies to eightfold, reducing the number and size of gaps in the final assembly over what would be obtained with 5.11-fold coverage. The two assembly strategies yielded very similar results that largely agree with independent mapping data. The assemblies effectively cover the euchromatic regions of the human chromosomes. More than 90% of the genome is in scaffold assemblies of 100,000 bp or more, and 25% of the genome is in scaffolds of 10 million bp or larger. Analysis of the genome sequence revealed 26,588 protein-encoding transcripts for which there was strong corroborating evidence and an additional approximately 12,000 computationally derived genes with mouse matches or other weak supporting evidence. Although gene-dense clusters are obvious, almost half the genes are dispersed in low G+C sequence separated by large tracts of apparently noncoding sequence. Only 1.1% of the genome is spanned by exons, whereas 24% is in introns, with 75% of the genome being intergenic DNA. Duplications of segmental blocks, ranging in size up to chromosomal lengths, are abundant throughout the genome and reveal a complex evolutionary history. Comparative genomic analysis indicates vertebrate expansions of genes associated with neuronal function, with tissue-specific developmental regulation, and with the hemostasis and immune systems. DNA sequence comparisons between the consensus sequence and publicly funded genome data provided locations of 2.1 million single-nucleotide polymorphisms (SNPs). A random pair of human haploid genomes differed at a rate of 1 bp per 1250 on average, but there was marked heterogeneity in the level of polymorphism across the genome. Less than 1% of all SNPs resulted in variation in proteins, but the task of determining which SNPs have functional consequences remains an open challenge.

Implementation of intraosseous infusion technique by aeromedical transport programs

Aeromedical transport program implementation of intraosseous infusion (IOI) was ascertained by telephone survey. One hundred thirty-three programs were polled: 69.2% had never utilized IOI nor were considering its use; 13.5% had previously utilized IOI; 15.8% had not yet implemented IOI but had been in-serviced on the technique; and 1.5% were considering implementation. Of 39 programs previously in-serviced or presently utilizing the procedure, seven restricted IOI insertion to physicians while 32 permitted placement by nurses or paramedics. Half of the programs would pursue IOI immediately after a 5-minute trial of peripheral line placement in preference to cutdown or central venous line attempts. About 50 IOI were performed by aeromedical transport personnel in 1986. Rate of successful insertion was approximately 80%. Complications were few and minor. This survey demonstrates that the simple, safe technique of IOI is being grossly under-utilized and warrants further consideration.

Propranolol inhibits adenylate cyclase and secretion stimulated by deoxycholic acid in the rabbit colon

Bile acids cause diarrhea by inducing colonic secretion, probably mediated through the cyclic AMP system. The aim was to determine the effects of an adenylate cyclase inhibitor, propranolol, on deoxycholic acid (DCA) stimulation of net secretion and the cyclic AMP system in the colon. In each of 30 New Zealand white rabbits, 0.9% NaC1 as control and 6 mM and 8 mM DCA were injected in random sequence into three colonic loops in situ. Propranolol, 4 mg per kg was administered intravenously to 12 of the 30 rabbits 1/2 hr before preparation of the loops, i.e., 5 1/2 hr before the rabbits were killed. In the 18 untreated animals, 6 and 8 mM DCA significantly stimulated colonic net secretion and mucosal adenylate cyclase activity; 6 mM DCA caused no change in mucosal phosphodiesterase activity, whereas 8 mM DCA caused a 25% decrease (P less than 0.01). In propranolol-treated animals compared to untreated animals, the volume of luminal fluid in controls was not different, with 6 mM DCA it was 88% less (P less than 0.01), and with 8 mM DCA it was 45% less (P less than 0.01); adenylate cyclase activity in controls was 43% less (P less than 0.01), with 6 mM DCA it was 67% less (P less than 0.01), and with 8 mM DCA it was 65% less (P less than 0.01); phosphodiesterase activity in controls and with 6 mM DCA was not different and with 8 mM DCA it was 38% greater (P less than 0.02). In conclusion, propranolol prevented DCA stimulation of colonic net secretion and inhibited the cyclic AMP system. Propranolol, therefore, warrants investigation as therapy for diarrhea caused by bile acids in the colon.