Dextran 40 (Rheomacrodex) or Polygeline (Haemaccel) as an epidural patch for post dural puncture headache: a neurotoxicity study in a rat model of Dextran 40 and Polygeline injected intrathecally.

BACKGROUND AND OBJECTIVE: Although an epidural autologous blood patch is considered the most effective treatment for post dural puncture headache, which sometimes occurs following spinal or inadvertent spinal anaesthesia, there remains a need for alternative materials for epidural patches. We investigated the potential neurotoxicity of Dextran 40 (Rheomacrodex) and Polygeline (Haemaccel) used for this purpose in a rat model. METHODS: Repeated boluses of 10% Dextran 40, 3.5% Polygeline or 0.9% saline were injected intrathecally over a period of 1 month in three groups of rats. RESULTS: No behavioural or clinical derangements were observed in any of the three groups during this period. After sacrifice of the animals at the end of the experiment, no significant differences in the histopathological appearances of the spinal cords in the three groups were observed. No toxic effects diminishing viability of spinal cord cells were evident. Similarly, viability of renal, hepatic and peripheral blood mononuclear cells remained unaffected (98% +/- 2%). CONCLUSIONS: No deleterious effects, clinical or cellular, were evident in this rat model when Dextran 40 or Polygeline were injected intrathecally. Thus, both substances can be considered as possible alternative materials for epidural patches.

Risk factors of atherosclerosis and saphenous vein endothelial function.

BACKGROUND: Impaired vasomotor function has been suggested as playing a role in the pathophysiology of atherosclerosis and it may also affect the late patency of bypass grafts. We evaluated, in vitro, the influence of risk factors of atherosclerosis on saphenous vein endothelial function in patients with cardiovascular diseases. METHODS: Forty-five saphenous vein rings with intact (E+) and denuded endothelium (E-) were studied. The following drugs were used: norepinephrine (NE), acetylcholine (Ach), histamine (H) and serotonine (5-HT). RESULTS: Contraction to norepinephrine (n=15) showed a maximal tension of 783+/-115 percent that was increased in diabetics, smokers, and patients with hypertension. There was a wide range of response to acetylcholine in rings with intact endothelium (n=25), (mean relaxation 16.4+/-1.7 percent, ranging from -22.2 percent to 45 percent) with relaxation (26+/-1.1 percent) and contraction (-11+/-1.2 percent); relaxation was reduced in patients with hypertension and in diabetics (7.4+/-2.6 percent vs non diabetics 24.4+/-1.73 percent; p<0.01). Five of the 12 veins from diabetics exibited contraction (10+/-1.48 percent). Histamine (n=15) caused moderate relaxation at low doses (25+/-2.46 percent) followed by contraction at higher concentrations (184+/-5.7 percent). This was greater in diabetics (193+/-6.8 percent vs non diabetics 157+/-5.3 percent; p=0.045) while in preparations without endothelium (n=10) only relaxation was obtained (45+/-2.89 percent). Contraction (242+/-7.4 percent) was observed in response to serotonine (n=15) that was not affected by endothelial removal. In this study saphenous vein: (1) exhibited a wide range of responses to acetylcholine; (2) evoked marked contraction to norepinephrine and serotonine; (3) elicited contraction in response to histamine that was endothelium-dependent, suggesting the production or the release of an endothelium-derived-contracting-factor (EDCF). CONCLUSIONS: Saphenous vein is able to secrete a contracting factor in patients with risk factors of atherosclerosis and above all diabetes. The mechanisms that regulate the balance between the relaxing and contracting factors and how the endothelial cells become the source of the substances with vasoconstrictor activity remain to be determined.

Lateral recumbent head-down posture for epidural catheter insertion reduces intravascular injection.

PURPOSE: The unintentional and unrecognized cannulation of an extradural vein is a potentially serious complication of an epidural anesthetic. The present study was undertaken to assess the incidence of blood vessel puncture related to epidural catheterization performed in three different body positions. METHODS: The study was conducted in 900 (three groups of 300) obstetric patients undergoing continuous epidural analgesia during their labour and who were randomly allocated to three groups. Epidural catheterization was performed with patients in the sitting, lateral recumbent horizontal, or lateral recumbent head-down position. RESULTS: There was a lower incidence of vessel cannulation when this procedure was performed in the lateral recumbent head-down position (2%) than in the lateral recumbent horizontal (6%) and in the sitting position (10.7%). CONCLUSION: Adoption of the lateral recumbent head-down position for the performance of lumbar epidural blockade, in labour at term, reduces the incidence of lumbar epidural venous puncture.

Double-blind treatment of major depression with dehydroepiandrosterone.

OBJECTIVE: This study was designed to assess possible antidepressant effects of dehydroepiandrosterone (DHEA), an abundant adrenocortical hormone in humans. METHOD: Twenty-two patients with major depression, either medication-free or on stabilized antidepressant regimens, received either DHEA (maximum dose = 90 mg/day) or placebo for 6 weeks in a double-blind manner and were rated at baseline and at the end of the 6 weeks with the Hamilton Depression Rating Scale. Patients previously stabilized with antidepressants had the study medication added to that regimen; others received DHEA or placebo alone. RESULTS: DHEA was associated with a significantly greater decrease in Hamilton depression scale ratings than was placebo. Five of the 11 patients treated with DHEA, compared with none of the 11 given placebo, showed a 50% decrease or greater in depressive symptoms. CONCLUSIONS: These results suggest that DHEA treatment may have significant antidepressant effects in some patients with major depression. Further, larger-scale trials are warranted.

Cervical reconstruction of the supra-aortic trunks: a 16-year experience.

PURPOSE: The purpose of this study was to review 182 consecutive cervical reconstructions of supra-aortic trunks, which were performed over a 16-year period. METHODS: A total of 182 innominate, common carotid, or subclavian arteries were reconstructed with a cervical approach in 173 patients aged 23 days to 83 years. Indications included hemispheric (n = 79), vertebrobasilar (n = 56), upper extremity (24), and internal mammary/cardiac ischemia (n = 5), asymptomatic severe common carotid disease (n = 33), or other (n = 3). Primary atherosclerotic innominate (n = 6), common carotid (n = 84), and subclavian (n = 66) lesions underwent reconstruction. Thirty-one operations were performed for multiple trunk involvement, recurrent disease, arteritis, infection, dissection, coarctation, or aneurysm. There were 122 bypass grafting procedures (98 ipsilateral, 24 contralateral) and 60 arterial transpositions. RESULTS: One death (0.5%) and 7 nonfatal strokes (3.8%) occurred, none in patients who were asymptomatic. Perioperative morbidity included four asymptomatic occlusions (2%), 6 myocardial infarctions (3%), 10 pulmonary complications (5%), and 2 graft infections (1%). Follow-up periods ranged from 1 to 190 months (mean, 53 +/- 5 months). Nineteen patients (10%) were lost to follow-up. Fifty-seven late deaths occurred, most from cardiac causes. Seven reconstructions necessitated late revision. The cumulative primary patency rate at 5 and 10 years was 91% +/- 2% and 82% +/- 5%, respectively. The survival rate at 5 years was 72% +/- 4% and at 10 years was 41% +/- 6%. The stroke-free survival rate was 92% +/- 2% at 5 years and 84% +/- 2% at 10 years. CONCLUSION: Cervical reconstruction of symptomatic and asymptomatic supra-aortic trunk lesions carries acceptable death and stroke rates and provides a long-term patient benefit. This should be the preferred approach for asymptomatic lesions and for patients with significant comorbidity because it carries less morbidity than direct transmediastinal aortic-based reconstruction.

Not disabled enough: the ADA's "major life activity" definition of disability.

Michelle Friedland argues in this note that the Americans with Disabilities Act fails to adequately distinguish between the separate goals of preventing pure discrimination and providing affirmative accommodation. The Act's conflation of these two different objectives, and its reliance on a single definition of disability for both, hinders its effectiveness in improving the status of individuals with disabilities in the employment setting. To illustrate this, she points to the counterintuitive results reached in recent court decisions. Friedland further traces the legislative origins of the Act's definition of disability and the ambiguity it leaves as to Congress's goals for the Act's employment provisions. She posits three possible goals the Act might be designed to achieve and recommends basic reforms for accomplishing each. Her ultimate conclusion is that provisions dealing with accommodation and discrimination need to be divided so that each can have its own definition of disability. In addition, she believes funding mechanisms for providing accommodation should be altered to ameliorate inequalities in burdens borne by employers and to avoid improper incentives to circumvent the Act.

Angiographic arterial occlusion and extra-anatomical vascular bypass for the management of a ureteral-iliac fistula: case report and review of the literature.

Ureteroarterial fistulas related to nonvascular etiology are rare clinical entities that are difficult to diagnose and manage. Diagnosis is best made by a combination of studies, including digital subtraction angiography. Low morbidity and mortality rates have been described with either percutaneous thrombosis of the iliac artery and extra-anatomic bypass, or by placement of a stented graft in the involved artery. We report on a well-documented case of a ureteroarterial fistula managed successfully with interventional radiologic embolization of the common iliac artery and immediate femoral-femoral arterial bypass. A review of the literature supports this approach.

Vena cava duplex imaging before caval interruption.

PURPOSE: Venacavograms are routinely obtained before vena cava filter placement to evaluate cava size, patency, and the presence of thrombus or venous anomalies. The objective of this study was to determine the ability of duplex ultrasonography to adequately evaluate the inferior vena cava (IVC) for size, patency, and the presence of thrombus before Greenfield filter (GF) insertion. METHODS: Duplex ultrasonographic scans were performed in 40 patients who had documented lower-extremity deep venous thrombosis diagnosed by duplex scan before GF placement. The infrarenal transverse and anteroposterior diameters of the IVC were measured, and the entire IVC was imaged for patency and the presence of thrombus or anomalies. Preoperative venacavograms were not obtained in any patients who had GFs placed in the operating room, but was performed during surgery during filter insertion. An additional 26 patients who had deep venous thrombosis and did not have caval interruption underwent IVC duplex to determine the patency and proximal extent of venous thrombosis. RESULTS: The indications for GF placement were contraindication to anticoagulation in 72.5% (29 patients); five filters were placed prophylactically; three for failure of anticoagulation; two after a complication of anticoagulation; and one before pulmonary embolectomy. The filters were placed in the operating room by surgeons in 82.5% of patients, with the remainder inserted in an angiography suite by an interventional radiologist. The ability of duplex to measure a transverse diameter of 26 mm or less had a sensitivity of 97.5%, positive predictive value of 100%, and overall accuracy of 97.5% using venacavography as the standard. Measurements of IVC diameter by duplex correlated with those based on venacavograms (r = 0.766; p < 0.001). Of the entire group of 66 IVC duplex examinations, one (1.5%) was incomplete because of technical limitations. IVC thrombus was noted by duplex in two patients who underwent GF insertion, which was confirmed with venacavography. No IVC anomalies were noted by duplex scans or venacavograms. CONCLUSION: Duplex ultrasonography is a useful and accurate method for assessment of the IVC before vena cava filter placement.

Drug-induced metabolic bone disease.

Drug-induced metabolic bone disease via modification of resorption, formation, and mineralization is responsible for a spectrum of disorders classified as osteoporosis, osteomalacia, and adynamic bone disease. Bone disease and the coincident risk of fracture and disability are well-documented with use of glucocorticoids, L-thyroxine, ethanol, tobacco, anticonvulsants, neuroleptics, and chemotherapeutic agents. Physician awareness of these risks highlights the need for close monitoring of dosages and drug interactions and allows for intervention with nutritional support, antiresorptive agents, and proformation agents.

Hypertonic saline resuscitation detrimentally affects renal function and survival in dehydrated rats.

The purpose of our studies was to determine whether hypertonic (7.5%) saline (HTS) resuscitation is effective in the setting of dehydration. We compared the effects of HTS (5 cc/kg) to those of Ringer's lactate (RL; 45 cc/kg) on renal function, following resuscitation from hypovolemia in hydrated (free access to food/water) vs. dehydrated (food/water restricted) rats (300-350 g). Renal failure was produced by hemorrhage (15 cc/kg) plus renal artery occlusion (25 min) followed by fluid resuscitation. Dehydration was confirmed by hemoconcentration and weight loss (8-10%). Renal function was assessed at 24 hr using 14C-inulin clearance (Cin) measurements. In hydrated animals, the Cin of RL-treated rats (625 +/- 54 microliters/min/100 g; n = 12) was no different from the Cin in HTS-treated rats (517 +/- 48 microliters/min/100 g; n = 13). Among dehydrated rats, Cin in HTS-treated rats (n = 6) was significantly lower (P < or = 0.05) than in RL-treated rats (n = 5) (117 +/- 33 microliters/min/100 g vs. 542 +/- 84 microliters/min/100 g, respectively). Cin in dehydrated RL-treated rats was not significantly different from that in hydrated RL-treated rats. Furthermore, in dehydrated animals, nine of nine resuscitated with RL survived, compared to six of 13 resuscitated with HTS. All hydrated animals survived. In summary, renal failure was ameliorated by RL and worsened by HTS resuscitation in dehydrated rats. Furthermore, mortality was increased in dehydrated animals resuscitated with HTS compared to RL.

Spontaneous regression of small cell carcinoma of lung associated with severe neuropathy.

This is a case report of small cell lung cancer (SCLC) that underwent spontaneous regression. This was associated with severe neuropathy, which was unresponsive to therapy, including corticosteroids and plasmapheresis. We present here the case report and a brief review of the literature.

Hageman factor deficiency presentation and implications for management.

One of the more fascinating aspects of patient management arises when dealing with coagulation disorders. Factor XII deficiency, first described by Ratnoff in 1968, is one such coagulation disorder which provides some interesting challenges in management. Factor XII deficiency has been shown to be an inherited autosomal recessive disorder. The presence of Hageman factor abnormality trait can be clinically suspected in a patient with a prolonged activated partial thromboplastin time (APTT), normal prothrombin time (PT), normal bleeding time, and no clinical history of bleeding. Once suspected, the deficiency can be confirmed by normalization of partial thromboplastin time (PTT) with normal aged plasma and by factor assay. The importance of understanding the mechanism of factor XII deficiency has clinical significance when attempts are made to heparinize individuals who have this deficiency. Three methods can be used to monitor therapy: the chromogenic heparin assay, the citrated thrombin time, and the recalcified thrombin time. Two cases are presented.

Hepatic angiosarcoma.

A patient with hepatic angiosarcoma is described. The significant aspects of this malignancy are delineated. This tumor constitutes only 2% of all primary tumors of the liver. The association with exposure to vinyl chloride and other carcinogens is reviewed. Diagnostic and therapeutic modalities are discussed.