Orthostatic hypotension induced by postural change in the rat (tilt test).

Postural-change-induced (orthostatic) hypotension is defined as an excessive drop in arterial blood pressure occurring when moving toward an upright position. This side effect, which may limit the therapeutic use of some agents, can occur with drugs, such as adrenoceptor blockers and vasodilators, that dampen sympathetic reflex activity. Described in this unit is a procedure for evaluating the effects of test substances on the changes in blood pressure and heart rate that occur in an anesthetized, normotensive rat during a tilting challenge (head-up position). In addition to being a relatively simple technique, this assay yields reproducible orthostatic hypotensive responses and allows for the investigation, in the same preparation, of several ascending doses of a test substance. Examples of results obtained with prazosin, an α1-adrenoceptor antagonist that is notorious for causing orthostatic hypotension, are provided for illustrative purposes.

Cardiomyopathic Syrian hamster as a model of congestive heart failure.

Cardiomyopathic Syrian hamsters (Bio TO-2 dilated strain) constitute an animal model of congestive heart failure, which progressively develops an alteration of cardiac function leading to decreased arterial blood pressure and musculo-cutaneous blood flow associated with a complex process of cardiac remodeling including left ventricle dilation, wall thinning, and greater collagen density. The protocols described in this unit are designed to assess the pharmacological effects of new therapeutic strategies on cardiac and systemic hemodynamics, morphometry (body and target organs weight), cardiac remodeling (left ventricle dilation and collagen density), and survival in this model of dilated cardiomyopathy. Examples of results obtained with enalapril, an angiotensin I converting enzyme inhibitor, are provided for illustrative purposes.

FDG-PET scan in local follow-up of irradiated head and neck squamous cell carcinomas.

We performed a prospective study to assess the value of positron emission tomography (PET) with 2-[18F]-fluoro-2-deoxy-D-glucose (FDG) in the prediction of local control in irradiated head and neck squamous cell carcinomas (HNSCCs). Forty-two patients with irradiated HNSCCs underwent 49 FDG-PET scans between 3 and 6 months after the end of radiotherapy. The mean follow-up time after the first FDG-PET scan was 17 months. The result of the FDG-PET scan was true-positive in 6 patients, false-positive in 7 patients, and true-negative in 29 patients. The sensitivity, specificity, positive predictive value, and negative predictive value of FDG-PET scanning were 100%, 81%, 46%, and 100%, respectively. We conclude that FDG-PET scanning is useful for prediction of therapy outcome in irradiated HNSCCs. No biopsy is needed for at least 1 year if an FDG-PET scan is negative. If the scan is positive and the biopsy is negative, decreased FDG uptake measured in a follow-up scan indicates that a local recurrence is unlikely.

[Complications with totally implantable venous access device. A retrospective of 116 cases]. / Complications des chambres à cathéter implantables. Etudes rétrospective de 116 cas.

OBJECTIVE: To evaluate the complications related to implantation and use of totally implantable venous access devices (TIVAD). METHODS: Retrospective study based on 116 TIVAD involving 113 adult patients (93M/20F, mean age 59 years). The implantation was achieved under local anaesthesia (69% of cases) and under general anaesthesia (31% of cases). RESULTS: The total TIVAD follow-up time was of 45 963 days (mean per device: 396 days). We used cephalic vein (95 cases), subclavian vein (13), internal jugular vein (4) and external jugular vein (4). A total of 27 complications were observed: 2 were related to the implantation (1 haematoma, 1 wrong positioning of the catheter), 25 were due to the use of the device, among which: 10 septicaemias (0.22/1 000 catheter days), 6 deep vein thrombosis (0.13/1 000 catheter days), 4 catheter obliterations (0.09/1 000 catheter days), one local infection (0.02/1 000 catheter days) and 4 catheter disconnections (0.09/1 000 catheter days) including 3 intra-cardiac migrations due to a defective model. These complications led to early removal of 14% of devices. The side of implantation and the type of venous access had no statistically significant incidence on postoperative complications. Operative accidents were avoided by the predominant use of venous access by dissection rather than by puncture. CONCLUSION: The complications described were considerable, notably during the intensive use of TIVAD. However they must not mask the benefits of such devices. They justify the training of medical staff and the development of preventive measures.