Rosa Novellas

Determination of renal vascular resistance in dogs with diabetes mellitus and hyperadrenocorticism.

In dogs, diabetes mellitus and hyperadrenocorticism are causes of hypertension associated with increases in vascular peripheral resistance. In human patients, the renal resistive index (ri) and pulsatility index (pi) are related to hypertension and diabetes and are used as indicators of disease severity. In this study the renal vascular resistance was measured in 12 dogs with hyperadrenocorticism, three with diabetes mellitus and four with both conditions, and the possible relationships between the two indices, blood pressure and biochemical parameters were investigated. Hypertension, defined as a systolic blood pressure more than 150 mmHg, was recorded in two of the dogs with hyperadrenocorticism and three of the dogs with hyperadrenocorticism and diabetes. The overall mean values for RI, PI and systolic blood pressure were higher in the diseased group of dogs than in 27 healthy dogs, and both indices were correlated with blood glucose concentration.

Assessment of renal vascular resistance and blood pressure in dogs and cats with renal disease

This study investigated the possible relationships between renal resistive index (RI) or pulsatility index (PI) and systolic blood pressure and biochemical and haematological parameters in dogs and cats with renal disease. The study included 50 dogs and 20 cats with renal disease. RI and PI were significantly higher in both dogs and cats with renal disease than in 27 healthy dogs and 10 healthy cats. In dogs, a significant negative correlation was found between RI and red blood cell count, and a positive correlation was found between PI and serum creatinine. In cats, a positive correlation was found between RI and serum urea, between PI and serum creatinine, and between PI and serum urea. No relationship could be found between either RI or PI and systolic blood pressure.

Renal Ultrasound in Dogs and Cats

Diagnostic imaging techniques for the urinary system include: radiology (excretory urography, cystography, double-contrast cystography, positive-contrast cystography, and retrograde urethrography), abdominal ultrasonography, Doppler ultrasound, CT, MRI and scintigraphy. Diseases of the urinary tract can be differentiated into those affecting the upper urinary tract (kidneys and ureters) and those affecting the lower urinary tract (bladder and urethra). Some of the diseases affecting the kidneys are produced by a disease of the lower urinary tract. In such cases the ultrasonographic study has to be as comprehensive as possible. Only few renal anomalies may give specific images in the ultrasound exam. Therefore, renal biopsy or fine needle aspiration (FNA) may be necessary to achieve a final diagnosis (Vaden, 2005). Rawlings et al. (2003) indicated that high quality renal biopsy specimens can be obtained using 14-gauge, double spring-activated biopsy needles during laparoscopy. Doppler ultrasonography is the study of the characteristics of blood flow (red blood cells) in both the systolic and diastolic phases of the circulatory cycle. There are some indices, such as the resistive index and the pulsatility index that have been applied to the assessment of renal parenchymal diseases. An increased resistive index may be suggestive of diffuse, infiltrative renal disease.

Abdominal radiographic and ultrasonographic findings in ferrets (Mustela putorius furo) with systemic coronavirus infection.

Ferret systemic coronavirus infection (FSCV) is a systemic disease in ferrets that clinically and pathologically resembles the dry form of FIP. The present study describes abdominal imaging features of 11 ferrets with FSCV. Abdominal survey radiographs were available for eight ferrets and ultrasound examination for all cases. Loss of lumbar musculature, decreased peritoneal detail, presence of mid-abdominal soft-tissue masses and splenomegaly were the most significant radiographic signs in these patients. Ultrasonographic findings including peritonitis, abdominal lymphadenopathy, splenomegaly, abdominal soft-tissue masses, nephromegaly and changes in the renal cortex echogenicity were recorded in the majority of cases with FSCV. As an imaging modality, ultrasound is superior to radiology when abdominal contrast is reduced, as it frequently occurs in these cases. However, although imaging techniques provide additional information in the antemortem diagnosis, they can not replace the definitive diagnosis based on histological and immunohistochemical results.

Effect of delayed acquisition times on gadolinium-enhanced magnetic resonance imaging of the presumably normal canine brain.

A delay in imaging following intravenous contrast medium administration has been recommended to reduce misdiagnoses. However, the normal variation of contrast enhancement in dogs following a delay has not been characterized. Contrast-enhanced MR imaging of 22 dogs was assessed, in terms of identification of normal anatomic structures, to investigate the variation associated with 10-min delay between contrast medium administration and imaging. All dogs had a normal brain MR imaging study and unremarkable cerebrospinal fluid. Specific regions of interest were assessed both objectively, using computer software, and subjectively using three observers. Mean contrast enhancement > 10% was seen in the pituitary gland, choroid plexus, meninges, temporal muscle, trigeminal nerve, and the trigeminal nerve root. Structures with an active blood-brain barrier had minimal contrast enhancement (< 6%). Enhancing structures had significantly more contrast enhancement at t = 1 min vs. t = 10 min, except in temporal muscle, the trigeminal nerve and the trigeminal nerve root. Interobserver agreement was moderate to good in favor of the initial postcontrast T1-weighted (T1w) sequence. The observers found either no difference or poor agreement in identification of the nonvascular structures. Intraobserver agreement was very good with all vascular structures and most nonvascular structures. A degree of meningeal enhancement was a consistent finding. The initial acquisition had higher enhancement characteristics and observer agreement for some structures; however, contrast-to-noise was comparable in the delayed phase or not significantly different. We provide baseline references and suggest that the initial T1w postcontrast sequence is preferable but not essential should a delayed postcontrast T1w sequence be performed.

Non-invasive in vivo measurement of cardiac output in C57BL/6 mice using high frequency transthoracic ultrasound: evaluation of gender and body weight effects

Even though mice are being increasingly used as models for human cardiovascular diseases, non-invasive monitoring of cardiovascular parameters such as cardiac output (CO) in this species is challenging. In most cases, the effects of gender and body weight (BW) on these parameters have not been studied. The objective of this study was to provide normal reference values for CO in C57BL/6 mice, and to describe possible gender and/or BW associated differences between them. We used 30-MHz transthoracic Doppler ultrasound to measure hemodynamic parameters in the ascending aorta [heart rate (HR), stroke volume (SV), stroke index (SI), CO, and cardiac index (CI)] in ten anesthetized mice of either sex. No differences were found for HR, SV, and CO. Both SI and CI were statistically lower in males. However, after normalization for BW, these differences disappeared. These results suggest that if comparisons of cardiovascular parameters are to be made between male and female mice, values should be standardized for BW.

Doppler evaluation of the effects of propofol, etomidate and alphaxalone on fetoplacental circulation hemodynamics in the pregnant ewe

INTRODUCTION Umbilical artery (UA) hemodynamics reflect blood flow and vascular resistance in the placental circulation. We examined non-invasively the hemodynamic effects of propofol, etomidate, and alphaxalone on the placental circulation of a sheep model by means of UA Doppler ultrasonography. METHODS Eleven sheep fetuses were examined at 90-109 days of gestation. UA Doppler ultrasound was performed before and after administration of a single intravenous bolus of propofol, etomidate, or alphaxalone. UA Doppler velocities (peak systolic velocity, end diastolic velocity, and mean velocity), vascular indices (pulsatility index, resistance index, and S/D ratio), blood flow, and fetal heart rate were recorded during the experimental period and UA Doppler waveforms were characterized. RESULTS A laminar, parabolic, low resistance flow was observed in the UA of the sheep fetuses. No statistically significant changes were observed in the UA Doppler waveforms or in the UA Doppler hemodynamics after anesthesia induction. DISCUSSION Changes in placental vascular resistance may alter the corresponding UA Doppler waveforms. When resistance in the fetal placenta increases, blood flow in the UA becomes more pulsatile. In the present study, umbilical arteries showed a parabolic flow with low resistance in all cases, as it occurs in normal human pregnancy. The administration of these anesthetics did not cause abnormalities in the normal UA Doppler pattern, inducing no changes in the resistance of the placenta in any case. CONCLUSION These results suggest that intravenous anesthetic induction with propofol, etomidate, or alphaxalone does not cause significant detrimental effects on the placental circulation of the pregnant ewe.

Comparison between ultrasonographic findings of benign and malignant canine mammary gland tumours using B-mode, colour Doppler, power Doppler and spectral Doppler

The aim of this study was to evaluate whether the comparison between the ultrasonographic features of canine mammary tumours, assessed by B-Mode, colour Doppler, power Doppler, spectral Doppler, and histopathologic features, would help to differentiate if a tumour is benign or malignant. Ultrasonographic examinations of 104 tumours were performed. Volume, margins, presence of a capsule, echotexture and presence and distribution of the vascular flow of the tumours were evaluated. All the tumours were surgically removed, submitted for histopathologic examination and classified in two groups: Group I (benign tumours) and Group II (malignant tumours). Echotexture was the only parameter evaluated by B-Mode ultrasonography where significant differences were found (p<0.01), with tumours in Group I being homogeneous and tumours in Group II presenting greater heterogeneity. Presence of vascular flow was observed in most of the tumours from both groups and no differences between them were found. Regarding flow distribution, significant differences were observed between groups (p<0.05). In benign tumours, the most common vascular pattern was the peripheral, showing significant differences (p<0.05) compared to mixed and central patterns. In malignant tumours the mixed pattern was the most frequent. Also significant differences among other patterns (peripheral and central) were found. Concerning vascular resistivity and pulsatility indexes, there were no significant differences between the two groups. The echotexture and type of vascular flow pattern of canine mammary gland tumours may help, in a first examination of the tumour, to differentiate between benign and malignant tumours; however to reach a definitive diagnosis histological study is required.

In vivo tracking and immunological properties of pulsed porcine monocyte-derived dendritic cells

Cellular therapies using immune cells and in particular dendritic cells (DCs) are being increasingly applied in clinical trials and vaccines. Their success partially depends on accurate delivery of cells to target organs or migration to lymph nodes. Delivery and subsequent migration of cells to regional lymph nodes is essential for effective stimulation of the immune system. Thus, the design of an optimal DC therapy would be improved by optimizing technologies for monitoring DC trafficking. Magnetic resonance imaging (MRI) represents a powerful tool for non-invasive imaging of DC migration in vivo. Domestic pigs share similarities with humans and represent an excellent animal model for immunological studies. The aim of this study was to investigate the possibility using pigs as models for DC tracking in vivo. Porcine monocyte derived DC (MoDC) culture with superparamagnetic iron oxide (SPIO) particles was standardized on the basis of SPIO concentration and culture viability. Phenotype, cytokine production and mixed lymphocyte reaction assay confirmed that porcine SPIO-MoDC culture were similar to mock MoDCs and fully functional in vivo. Alike, similar patterns were obtained in human MoDCs. After subcutaneous inoculation in pigs, porcine SPIO-MoDC migration to regional lymph nodes was detected by MRI and confirmed by Perls staining of draining lymph nodes. Moreover, after one dose of virus-like particles-pulsed MoDCs specific local and systemic responses were confirmed using ELISPOT IFN-γ in pigs. In summary, the results in this work showed that after one single subcutaneous dose of pulsed MoDCs, pigs were able to elicit specific local and systemic immune responses. Additionally, the dynamic imaging of MRI-based DC tracking was shown using SPIO particles. This proof-of-principle study shows the potential of using pigs as a suitable animal model to test DC trafficking with the aim of improving cellular therapies.

Successful medical management of pseudomembranous cystitis in three cats with lower urinary tract obstruction

CASE REPORT The present case series describes the clinical course and outcome of three cats diagnosed with pseudomembranous cystitis. This is an uncommon presentation of lower urinary tract obstruction but can be easily be identified by ultrasonography, revealing severe bladder wall thickening and thin hyperechoic luminal strips. The condition can be secondary to severe bacterial urinary tract infection. All cats were successfully treated with medical management only, mainly based on antimicrobials and individualised supportive therapy. CONCLUSION Further evaluation of this condition is necessary in order to determine potential underlying aetiologies, pathophysiological mechanisms and the most appropriate standardised treatment.