Effects of gamma-hydroxybutyrate on cerebrospinal fluid lactate and glucose levels after spinal cord trauma.

This study aims to evaluate the effects of gamma-hydroxybutyrate (GHB) after spinal cord trauma (SCT). Twenty rabbits were divided equally into four groups: group I was the sham-operated group, group II suffered from SCT but received no treatment, group III was given a dose of 400 mg/kg of GHB intravenously before SCT and group IV received the same dose after SCT. Cerebrospinal fluid (CSF) samples were obtained 30 min before SCT (T(0)), at 60 (T(1)) and 120 min (T(2)) after SCT. There was a threefold increase in lactate levels from baseline value at T(2) in group II, while statistically significant elevation of the lactate levels were not observed in groups III and IV. Glucose levels at T(1) and T(2) were significantly lower in groups III and IV compared with the control group. The findings of this study demonstrate that GHB can control the increase of CSF lactate and glucose levels following SCT and that this metabolic effect may be associated with neuroprotective physiological changes.     

The potential of intradialytic parenteral nutrition: A review

Malnutrition is common in chronic hemodialysis (CHD) patients and is strongly related to increased morbidity and mortality. Among the various approaches to treat malnutrition in this patient population, intradialytic parenteral nutrition (IDPN) is the treatment of choice for a small but important percentage of malnourished CHD patients. However, the new revised policies relating to IDPN reimbursement by Medicare in the US have made it very difficult to qualify patients for this potentially useful therapy. This restrictive policy was adopted mainly because there are no clear data that support IDPN use or efficacy. Studies to date in the literature do not provide clear documentation of the benefits of IDPN or their cost-effectiveness. The purpose of this review is to critically evaluate studies relating to the use of IDPN as a potential therapy to treat malnutrition in CHD patients and to discuss potential trials to prove its cost-effectiveness.     

Antibiotic prophylaxis influences cardiovascular stability in complicated surgery

Objective:Antibiotic prophylaxis is used in many surgical procedures but there are frequent cardiovascular instabilities following antibiotics in perioperative period. A clinic modelling randomised trial (CMRT) in pigs was developed to compare the effects of 2 commonly used antibiotic combinations on cardiovascular stability during major surgery. Materials and methods:Thirty pigs (both sexes) were randomised into 3 groups, receiving either saline (placebo), co-amoxiclav or cefuroxime/metronidazole in clinically relevant doses as antibiotic prophylaxis. A laparotomy was performed and the abdomen remained open. Surgical complications were simulated by removing one third of the blood volume. For fluid resuscitation, 500 ml hetastarch (HAES^TM) were infused rapidly (therapy of complication) and polymyxin B (15 mg/kg bodyweight) was applied for induction of histamine release reactions (complication of therapy). The main end points were histamine release reactions, these were classified by 2 blinded investigators. Results:Neither cardiovascular changes nor histamine release reactions were detected immediately after the administration of antibiotics or placebo alone. Plasma histamine concentrations increased after bleeding in the co-amoxiclav group (p < 0.05). After fluid resuscitation and induction of anaphylactoid reactions, the median histamine release and cardiovascular changes were not significantly different between the groups. However, the incidence of typical histamine release related reactions differed significantly between the groups: 8/10 for the controls, 6/10 in the co-amoxiclav and 2/10 in the cefuroxime/metronidazole group (p < 0.05). Conclusions:The stability and reproducibility of this model clearly demonstrated the concept of a ‘clinic modelling randomised trial’ as a useful tool. Antibiotic prophylaxis influences the organism’s capability to cope with intraoperative bleeding and fluid resuscitation problems. Indeed antibiotic prophylaxis may be beneficial. These effects of antibiotics could only be demonstrated in complex surgical models. Thus new antibiotics should be investigated in complex animal models prior to prospective randomised clinical trials or usage in clinical practice.     

Glomerular changes in BK virus nephropathy

This study seeks to define the glomerular changes that are associated with human BK virus nephropathy (BKVN). It is based on histopathologic review of 124 biopsies showing light-microscopic changes of viral nephropathy. The diagnosis of BKVN was confirmed by immunohistochemistry or by in situ hybridization. Histological lesions were scored by the Banff 97 criteria for renal allograft pathology and were correlated with clinical parameters. Viral cytopathic effect in the parietal Bowman's capsular epithelium was seen in 21/124 (17%) biopsies. Immunohistochemistry showed infection of Bowman's capsular epithelium in an additional 15/124 (12%) biopsies. Crescents were found in 15/124 (12%) samples. Glomerulitis exceeding grade Banff g1 was only occasionally shown (4/124=3% biopsies). Other pathologic lesions documented include mild increase in mesangial matrix in 23% biopsies, aneurysmal dilatation of glomerular capillaries in 28%, ischemic glomerulopathy in 62%, and chronic transplant glomerulopathy graded as mild (cg1) in 62% of biopsies and as moderate (cg2) in 2/124 (1.9%) biopsies. These findings show that infection of the glomerular epithelium cells can occur in a subset of patients with BKVN, most often in biopsies with high viral load in the tubular epithelium. Isolated crescents can occur in BKVN biopsies, but rapidly progressive glomerulonephritis is not observed. Two biopsies showed electron-dense deposits on ultrastructural examination, but a cause and effect relationship to BK virus infection could not be established.     

Results of rhabdomyosarcoma treatment in a developing country

Fifty-one children (median age: 4.5 years; 4 months-16 years) diagnosed with rhabdomyosarcoma were treated in our center between 1980-1999. The primary sites were head and neck in 31.4%, the genito-urinary system in 21.6%, and extremities in 9.8% of the patients. The histopathologic subtypes were embryonal in 80.4%, alveolar in 9.8%, and undifferentiated in 9.8%. The majority of the patients were considered group III (47%) and group IV (25.5%) according the criteria of the Intergroup Rhabdomyosarcoma Study (IRS). Primary total tumour resection was performed in only 27.5% of the patients. The patients were treated with assigned regimens of IRS II and IRS III protocols. Radiotherapy was applied to 92.1% of the patients. Thirty-four patients (66.7%) were lost to follow up, and of the remaining 17 patients, 7 patients (41.2%) died, relapse occurred in 9 patients (52.9%) and 10 patients (58.8%) are alive. The percentage of cases lost to follow up during the first 10 years and the following 9 years of the study were 77.4% and 50%, respectively. In compliance with cancer treatment remains a major problem in developing countries.     

Premedication with H1 and H2 blocking agents reduces the incidence of postoperative nausea and vomiting

Objective:Patients undergoing anaesthesia and surgery frequently complain about postoperative nausea and vomiting (PONV). Whether pretreatment with H₁ and H₂ blocking agents reduces the incidence of PONV remains controversial. To answer this question, we performed a randomised, prospective, placebo-controlled clinical study to evaluate the efficacy of a premedication with H₁ and H₂ receptor antagonists. Material and Subjects:1149 patients (both sexes) undergoing surgery were randomly assigned to three treatment groups and one control group. Patients in the treatment groups were premedicated with the following H₁ + H₂ receptor antagonists:Group 1 (n = 335): 5 mg/kg cimetidine i.v. + 0.1 mg/kg dimetindene i.v. 20 min before induction of anaesthesiaGroup 2 (n = 337): 1.25 mg/kg ranitidine i.v. + 0.1 mg/kg dimetindene i.v. 20 min before induction of anaesthesiaGroup 3 (n = 316): 300 mg ranitidine p.o. + 0.1 mg/kg dimetindene i.v. 1 to 2 h before induction of anaesthesiaGroup 4 (n = 161): 20 ml saline solution i.v. 20 min before induction of anaesthesiaPatients from the treatment groups 1, 2 and 3 received regional or general anaesthesia depending on the clinical decision. All control patients received general anaesthesia consisting of fentanyl, a thiobarbiturate, enflurane, nitrous oxide, oxygen, and vecuronium. Results:The incidence of nausea and vomiting was 8.5%, 6.8% and 5.4% in patients from the treatment groups (1, 2 and 3) who underwent general anaesthesia (n = 545), with no statistically significant differences between groups. The incidence of nausea and vomiting in the control group (n = 161) was 28.3% (nausea) and 27.5% (vomiting), respectively. In patients who underwent regional anaesthesia (n = 443), the incidence of nausea and vomiting was 2.5% and 1.1%, respectively. Conclusions:Premedication with H₁ and H₂ blocking agents significantly reduces the incidence of postoperative nausea and vomiting.     

Biocompatibility of dialysis membranes: effects of chronic complement activation

The ability of three dialysis membranes (cuprophane, cellulose acetate, and polymethylmethacrylate) to activate complement was studied prospectively in ten chronic dialysis patients using new and reused membranes. Patients were dialyzed for 1 month with each type of membrane. New cuprophane membranes caused the most intense activation, while polymethylmethacrylate (PMMA) surfaces caused the least degree of complement activation. Reuse decreases the capacity of the cuprophane membrane to activate complement but does not significantly alter the capacity of cellulose acetate membranes. The extent of complement activation paralleled the ability of these membranes to induce neutropenia. Recurrent dialysis with new cuprophane and cellulose acetate membranes leads to a decrease in pre-dialysis and "rebound leukocytosis" neutrophil count, as well as a more intense activation of complement and an enhanced endogenous clearance of products of complement activation. The clinical sequelae of recurrent complement activation are discussed.     

Preserving function and long-term patency of dialysis access

Of the 283, 932 patients with end stage renal disease (ESRD) receiving replacement therapy in the US in 1996, 62% were being treated with haemodialysis. Improved survival of haemodialysis patients coupled with the inability to provide enough renal transplants for the growing ESRD population has resulted in an increase in the average length of time patients spend on dialysis. Vascular accesses are, therefore, required to function for longer periods of time. Maintenance of a reliable access to the circulation has been described as the Achilles' heel of modern haemodialysis. Preserving access function and long-term patency are essential for efficient dialysis delivery.