Physical examination and CT to assess thoracic injury in 137 cats presented to UK referral hospitals after trauma

OBJECTIVES

The aim of the study was to describe clinical examination and thoracic CT (TCT) findings in cats after trauma, and to identify physical examination findings associated with both abnormalities on TCT and the need for therapeutic interventions.

METHODS

A multicentre, retrospective, observational study was conducted. Cats admitted to the participating hospitals with a history of blunt trauma and that underwent TCT were eligible. Data were collected on signalment, history, physical examination, TCT findings and subsequent interventions.

RESULTS

In total, 137 cats were included. Road traffic accidents (RTAs) were the most frequently reported cause of trauma (69%). Tachypnoea (32%), pale mucous membranes (22%) and dyspnoea (20%) were the most common abnormal findings on thoracic examination. The most frequently identified thoracic pathologies on TCT were atelectasis (34%), pulmonary contusions (33%), pneumothorax (29%) and pleural effusion (20%). Thoracocentesis was the most commonly performed intervention (12%), followed by chest drain placement (7%). A total of 45 (33%) cats had no physical examination abnormalities but did have abnormalities detected on TCT; six of these cats required interventions. Increasing numbers of thoracic abnormalities on clinical examination were associated with increasing likelihood of having abnormal findings on TCT (odds ratio [OR] 2.04, 95% confidence interval [CI] 1.21-3.44, P = 0.008) and of requiring an intervention (OR 1.82, 95% CI 1.32-2.51, P <0.001).

CONCLUSIONS AND RELEVANCE

RTAs were the most common reported cause of blunt trauma. Atelectasis, pulmonary contusions and pneumothorax were the most common abnormalities identified on TCT, and thoracic drainage was the most utilised intervention. TCT may be useful in identifying cats with normal thoracic physical examination findings that have significant thoracic pathology, and a high number of abnormal findings on thoracic examination should raise suspicion for both minor and major thoracic pathology. The results of this study can be used to assist in selecting appropriate cases for TCT after blunt trauma.

Endothelial CXCR7 regulates breast cancer metastasis

Atypical chemokine receptor CXCR7 (ACKR3) functions as a scavenger receptor for chemokine CXCL12, a molecule that promotes multiple steps in tumor growth and metastasis in breast cancer and multiple other malignancies. While normal vascular endothelium expresses low levels of CXCR7, marked upregulation of CXCR7 occurs in tumor vasculature in breast cancer and other tumors. To investigate effects of endothelial CXCR7 in breast cancer, we conditionally deleted this receptor from vascular endothelium of adult mice, generating CXCR7^ΔEND/ΔEND animals. CXCR7^ΔEND/ΔEND mice appeared phenotypically normal, although these animals exhibited a modest 35 ± 3% increase in plasma CXCL12 as compared with control. Using two different syngeneic, orthotopic tumor implant models of breast cancer, we discovered that CXCR7^ΔEND/ΔEND mice had significantly greater local recurrence of cancer following resection, elevated numbers of circulating tumor cells, and more spontaneous metastases. CXCR7^ΔEND/ΔEND mice also showed greater experimental metastases following intracardiac injection of cancer cells. These results establish that endothelial CXCR7 limits breast cancer metastasis at multiple steps in the metastatic cascade, advancing understanding of CXCL12 pathways in tumor environments and informing ongoing drug development targeting CXCR7 in cancer.

CXCL12-γ in primary tumors drives breast cancer metastasis

Compelling evidence shows that chemokine CXCL12 drives metastasis in multiple malignancies. Similar to other key cytokines in cancer, CXCL12 exists as several isoforms with distinct biophysical properties that may alter signaling and functional outputs. However, effects of CXCL12 isoforms in cancer remain unknown. CXCL12-α, β, and γ showed cell-type specific differences in activating signaling through G protein-dependent pathways in cell-based assays, while CXCL12-γ had greatest effects on recruitment of the adapter protein β-arrestin 2. CXCL12-β and γ also stimulated endothelial tube formation to a greater extent than CXCL12-α. To investigate effects of CXCL12 isoforms on tumor growth and metastasis, we used a mouse xenograft model of metastatic human breast cancer combining CXCR4+ breast cancer cells and mammary fibroblasts secreting an isoform of CXCL12. While all CXCL12 isoforms produced comparable growth of mammary tumors, CXCL12-γ significantly increased metastasis to bone marrow and other sites. Breast cancer cells originating from tumors with CXCL12-γ fibroblasts upregulated RANKL, contributing to bone marrow tropism of metastatic cancer cells. CXCL12-γ was expressed in metastatic tissues in mice, and we also detected CXCL12-γ in malignant pleural effusions from patients with breast cancer. In our mouse model, mammary fibroblasts disseminated to sites of breast cancer metastases, providing another mechanism to increase levels of CXCL12 in metastatic environments. These studies identify CXCL12-γ as a potent pro-metastatic molecule with important implications for cancer biology and effective therapeutic targeting of CXCL12 pathways.

Analytical description of dose profile behaviour in Gamma Knife radiosurgery

Stereotactic Gamma Knife radiosurgery utilizes ionizing beams from (60)Co sources and relies on a combination of collimator sizes, weighting, etc to generate a high-dose region that is conformal with a designated target volume. Dose computation is typically performed by computer, but in this paper, single collimator dose profile behaviour is modelled analytically and then extended to accommodate multiple collimators of different weights with co-located isocentres. The dose profile from a single helmet is derived from a top-hat beam profile approximation and an idealized symmetric distribution of sources is used to represent the 201 sources within a collimating helmet. The results from the analysis are validated by an independent numerical model and also compared with those obtained by other groups using numerical and experimental methods. With respect to multiple collimators, the relationship between the size (full width half maximum) of the irradiated volume and relative collimator weighting is also examined using the simple analytical model. The simplicity of the mathematics clarifies the relationship between beam profile, dose profile and multiple collimator behaviour, and provides data that compare favourably with published literature.

Stable periodic vortex shedding studied using computational fluid dynamics, laser sheet flow visualization, and MR imaging

Recirculating and detached flow patterns close to the carotid bifurcation are thought to play an important role in the development of carotid stenoses by promoting atherosclerosis. The aim of this study was to investigate a flow regime with strong transient characteristics, including vortex shedding and transport to develop methodologies appropriate to the analysis of carotid stenoses. The existence of a regular periodic vortex street behind a cylindrical flow obstruction was predicted and analysed in detail by Theodore van Karman in the early 20th century. This model was chosen in our study for both ease of phantom construction and of theoretical modelling using finite element computational fluid dynamics (CFD). The results of the theoretical calculations have been compared with two methods of flow visualization-laser sheet imaging and real-time echo planar magnitude MR imaging. Flow was investigated over a range of Reynold's number from 40 through 400 through which vortex shedding is predicted. Good overall agreement was obtained between the theoretical (16 mm-CFD) and experimental (16+/-2 mm-Laser, 17+/-2 mm-MRI) estimates of the Karman Vortex street wavelength for a Reynolds number of 200.

Angiotensin II as a potential method of targeting cytotoxic-loaded microspheres in patients with colorectal liver metastases

Regional chemotherapy is commonly used to treat patients with colorectal liver metastases. However, improvement in survival has still not been demonstrated. Cytotoxic loaded albumin microspheres for arterial administration have been described as a means of improving the the therapeutic index, but their distribution depends upon the prevailing pattern of arterial blood-flow at the time of injection. In this study, the ability of the vasoactive drug angiotensin II to target arterially injected microspheres to colorectal liver metastases is assessed in nine patients using scintigraphic planar and tomographic imaging. The median tumour: normal ratio in nine patients with colorectal liver metastases was 3.4:1 before the administration of angiotensin II. The corresponding ratio after administration of angiotensin II was 7.3:1. The median improvement factor was 1.8 (P less than 0.05). The data suggest that worthwhile tumour targeting can be achieved with angiotensin II in patients with colorectal liver metastases.

Effects of the 65-mph speed limit on rural interstate fatalities in New Mexico

As a result of federal legislation passed in April 1987, New Mexico was the first state to resume a 65-mph speed limit on rural Interstate highways. We compared the rates of fatal crashes before and after the speed limit change. The rate of fatal crashes in the 1 year after the speed limit was increased was 2.9 per 100 million vehicle-miles traveled, compared with a predicted rate of 1.5 per 100 million vehicle-miles based on the trend of the 5 previous years. When fatal crashes that occurred after the speed limit change were compared with fatal crashes in the 5 previous years, there was no difference in the mean age and sex of the at-fault drivers, mean age and sex of the victims, seat belt use by the victims, or alcohol involvement of the crashes. The increase in fatal crashes can be attributed to an increase in fatal single-vehicle crashes. Vehicles on rural Interstates are traveling at greater rates of speed and a larger proportion of vehicles are exceeding the 65-mph speed limit. The benefits associated with the 65-mph speed limit should be weighed against the increased loss of lives.

Clinical evaluation of angiotensin II enhanced perfusion scintigraphy in metastatic liver disease

The hepatic perfusion index (HPI) may be of value in the diagnosis of liver micro-metastases. However, raised values of HPI also occur in some benign liver conditions (e.g. cirrhosis), thereby weakening the diagnostic power of this test. It has been suggested that infusion of the vaso-active agent angiotensin II might improve the predictive value of dynamic scintigraphy because it has been shown to alter liver perfusion in patients with metastatic liver disease. Basal HPI values were not significantly different in a group of patients with metastases (n = 10) and a group with cirrhosis (n = 9). A significant rise in HPI occurred in the metastatic group using angiotensin II enhancement (p less than 0.01, Wilcoxon test). In the cirrhotic group there was no significant increase in the HPI with angiotensin II enhancement. Within the groups, there was considerable variation in response, with eight of ten metastatic and five of nine cirrhotic patients showing a rise in HPI during an angiotensin II infusion. As a result, there was complete overlap in the angiotensin II enhanced HPI for the two groups. Angiotensin II enhancement of HPI is therefore unlikely to improve the diagnostic power of dynamic scintigraphy in individual patients with established hepatic disease.

Cefoperazone plus piperacillin versus mezlocillin plus tobramycin as empiric therapy for febrile episodes in neutropenic patients

The double beta-lactam combination of cefoperazone plus piperacillin was compared with an aminoglycoside-containing regimen of mezlocillin plus tobramycin in a prospective, randomized trial of empiric therapy for febrile neutropenic patients (neutrophils no more than 1,000/mm3). Thirty febrile episodes were treated with cefoperazone plus piperacillin and mezlocillin plus tobramycin, respectively. There was no significant difference between the two groups with respect to age, sex, pretherapy neutrophil count, and mean duration of therapy. The majority of patients had neutrophil counts of no more than 200/mm3 at the initiation of therapy. Only microbiologically and clinically documented infections were evaluated for efficacy. The cefoperazone plus piperacillin regimen appeared to have a comparable response rate with the mezlocillin plus tobramycin regimen (20 of 24 patients [83 percent] versus 16 of 23 patients [70 percent]). Gram-positive micro-organisms were seen predominantly in this study, with the cefoperazone plus piperacillin regimen achieving a bacteriologic response in 84 percent, as opposed to 60 percent for those organisms treated with the mezlocillin plus tobramycin regimen. Neither regimen was totally effective against coagulase-negative staphylococci. Eight superinfections occurred in the cefoperazone plus piperacillin arm, whereas 11 superinfections occurred in the mezlocillin plus tobramycin arm. Although fungal superinfections were most common, the number of gram-positive superinfections in the mezlocillin plus tobramycin arm exceeded those seen in the cefoperazone plus piperacillin arm. The incidence of antibiotic-related side effects was similar in the two groups. Hypokalemia was most frequently seen. Both skin rashes and nephrotoxicity were more common with mezlocillin plus tobramycin. Cefoperazone plus piperacillin was found to be effective empiric therapy in febrile neutropenic patients. This double beta-lactam combination may be particularly useful for patients who have or are at high risk for the development of renal insufficiency.

Child restraint law effects on motor vehicle accident fatalities and injuries: the New Mexico experience

The New Mexico State Legislature passed a child restraint law applicable to children less than 5 years of age that became effective in June 1983. To evaluate the effectiveness of this law, we analyzed traffic accident data for New Mexico from January 1981 through September 1984. During this period, there were 20,972 children younger than 5 years of age in motor vehicle accidents. Restraint usage increased for this age group from a low of about 10% in 1981 to more than 40% in 1984 (P less than 10(-6)). Unrestrained children younger than 5 years of age were five times more likely to be killed and two times more likely to be injured than restrained children. Analysis of motor vehicle accident fatality and injury rates pre- and post-law revealed a 33% reduction in motor vehicle accident fatality rates and a 12.6% reduction in nonfatal injury rates for children younger than 5 years. We conclude that child restraint devices are effective in reducing motor vehicle accident fatalities and injuries in young children and the child restraint law has been effective in increasing child restraint usage and in reducing childhood death and injury in New Mexico.