Leukocyte Depletion of Blood Cardioplegia Attenuates Reperfusion Injury

Background. Leukocytes are associated with myocardial injury during reperfusion after ischemia. Short periods of leukocyte depletion during reperfusion result in persistent attenuation of postischemic myocardial dysfunction.

Methods. Leukocyte depletion was examined in a canine model of regional myocardial ischemia and reperfusion. The extracorporeal circuit and cardioplegia circuits underwent leukocyte depletion by mechanical filtration. Animals were instrumented for baseline global function before 90-minute occlusion of the left anterior descending coronary artery. Global function during ischemia and at 5, 30, 60, and 90 minutes after a 60-minute cardioplegic arrest using continuous blood cardioplegia was assessed in leukocyte-depleted (n = 9) and control (n = 10) groups.

Results. No significant difference between groups was seen for systemic leukocyte counts, global function, or water content. Endothelial function was significantly protected as assessed by response to both calcium ionophore (endothelial-dependent, receptor-independent relaxation: leukocyte-depleted, 72% ± 19% of endothelin-induced constriction versus control, 46% ± 14%; p < 0.05) and acetylcholine (endothelial-dependent, receptor-dependent relaxation: leukocyte-depleted, 83% ± 11% versus control, 44% ± 15%; p < 0.05).

Conclusions. Leukocyte-mediated endothelial reperfusion injury can be attenuated by leukocyte depletion during reperfusion.     

Thoracic Epidural Anesthesia Attenuates Hemorrhage-induced Impairment of Intestinal Perfusion in Rats

Background: During hemorrhagic hypotension, sympathetic vasoconstriction crucially contributes to gut mucosal damage. Sympathetic blockade by thoracic epidural anesthesia has been shown to increase mucosal microvascular perfusion and to improve survival after severe hemorrhage in laboratory animals. This study investigates the effects of thoracic epidural anesthesia on intestinal microvascular perfusion during hemorrhagic hypotension in rats.

Methods: In 32 anesthetized Sprague-Dawley rats either lidocaine 2% (thoracic epidural anesthesia) or normal saline (control) was infused via thoracic epidural catheters. Hemorrhagic hypotension (mean arterial pressure 30 mmHg for 60 min) was induced by withdrawal of blood, which was subsequently retransfused for resuscitation. Functional capillary density and erythrocyte velocity in the mucosa and muscularis were determined by intravital microscopy. Leukocyte-endothelium interaction was studied in postcapillary venules and sympathetic nerve fibers of the intestinal wall were identified by immunohistochemistry.

Results: During hypotension functional capillary density was significantly (P < 0.001) lower in the muscularis of the control group (median [25/75 percentile]: -46.5% [-59.6/-20.8%] change from baseline) as compared with animals that received thoracic epidural anesthesia (-6.1% [-13.4/1.1%]). There were no differences in erythrocyte velocity between groups throughout the experiment. Leukocyte rolling increased significantly (P < 0.001) after resuscitation in control (12 [6/15]vs. baseline 2.5 [1/8]) but not in thoracic epidural anesthesia (4 [2.3/7]vs. baseline: 5 [3/15.5]). Sympathetic nerve fibers were identified in the muscularis and submucosa but not in the mucosa.     

The effect of nimodipine on ICP and CBF in patients with normal-pressure hydrocephalus

Eight patients with normal-pressure hydrocephalus (NPH) were studied. The resting mean arterial blood pressure (MABP) was 100 (90-125) mmHg and the mean intracranial pressure (ICP) was 11 (5-17) mmHg. ICP and MABP were continuously measured intraventricularly and intra-arterially, respectively. Changes in global cerebral blood flow (CBF) were estimated by the arteriovenous oxygen difference method. Intravenous nimodipine (15 microgram/kg/hour) was given in the first 2 hours and 30 microgram/kg/hour in the next 2 hours. MABP was reduced 23 (4-47) mmHg (p less than 0.05). ICP was increased 3 (0-10) mmHg (p less than 0.05). CBF was unchanged in the group on the whole, but in 4 of patients a major drop in perfusion pressure was seen, and CBF decreased 6, 11, 23 and 34%, respectively. Thus these findings underline the importance of maintaining the perfusion pressure under treatment with nimodipine.     

Post-prostatectomy urinary incontinence: response to behavioral training

Urinary incontinence after prostatectomy can be psychologically and socially disabling. We reviewed our experience with 27 patients who were incontinent between 5 and 198 months after either radical retropubic, total perineal or transurethral prostatectomy. These patients were entered into our bladder behavior clinic, which was administered by nursing staff with physician supervision. Patients were strongly encouraged to discontinue the incontinence devices, and were then evaluated for the type and extent of incontinence. Perineal exercises were demonstrated in detail, tested for their correct use via simultaneous rectal and abdominal examination, and applied to the pattern of incontinence. Patients were evaluated frequently for compliance and their progress was followed with instruction repeated as needed. Pharmaceutical agents were not used. Among the 24 patients evaluable over-all improvement in the number of incontinent episodes was 56.6% (p less than 0.001). Two patients (8.3%) achieved total continence, 10 (42%) improved greatly, 4 showed moderate improvement and 8 (33%) showed essentially no change. Transurethral and perineal prostatectomy patients improved by 74 and 61%, respectively, versus only 33% in the radical retropubic group (p = 0.14). In addition, patients who previously underwent transurethral resection before total prostatectomy did worse (18%) than did those who did not (67%). We conclude that a significant number of patients who are incontinent after prostatectomy (especially those without a prior transurethral resection) can improve dramatically with a behavioral training program that provides a strong support system.     

Further experience with division of the left renal vein

The left renal vein (LRV) has numerous tributaries including, but not limited to, the inferior phrenic, suprarenal, and gonadal veins. The resultant potential for collateral LRV outflow through these tributaries in instances of LRV division is obvious. One of us has previously reported 10 such cases of LRV division (close to its confluence with the inferior vena cava and without reanastomosis) for the purpose of facilitating proximal abdominal aortic exposure for reconstructive procedures. One of the 10 patients had moderate renal insufficiency at follow-up. We present herein an additional 19 patients who underwent LRV division predominantly for aneurysmal disease of the abdominal aorta. Sixteen patients were available for follow-up. Three patients died in the intraoperative and early postoperative periods. Multivariate analysis of variance of preoperative, postoperative, and follow-up laboratory data--serum creatinine and BUN--showed no significant change in renal function as assessed.     

A comprehensive survey for polymorphisms in the bovine IFN-gamma gene reveals a highly polymorphic intronic DNA sequence allowing improved genotyping of Bovinae.

This study aimed to identify interferon-gamma (IFN-gamma) gene variants in cattle for diagnostic purposes. Therefore, the entire bovine IFN-gamma gene (BoIFNG) and 2605 bp of its promoter DNA were sequenced. The BoIFNG DNA sequence conforms to the published part of Bo-IFN-gamma cDNA. Primer extension experiments show the presence of a 5' extension of exon 1 by 42 nucleotides (nt). One SINE element (Bov-A2) is located in the 5'-region, and two SINE elements (Bov-tA, Bov-B) are contained in the 3'-region of BoIFNG. The variants were detected by comparative sequence analysis of PCR amplicons from different bovine species. Four polymorphic mononucleotide repeats are situated in the promoter and in intron 1. Four distinct series of single nucleotide polymorphisms (SNP) were found in functionally important regions of BoIFNG. The region between the two intron 1 microsatellites contains the highest density of SNPs in Bos taurus breeds. One G-T transversion in the coding region of exon 1 causes a Gly(14) to Val(14) exchange in the BoIFNG signal peptide of different bovine species. A G-A transition in exon 2 encodes a Ser(19) to Asn(19) change in the mature protein of the Tibetan yak. Genotyping of randomly sampled Holstein Friesian cows at selected SNPs and of both intron 1 microsatellites revealed two dominant BoIFNG microhaplotypes. The detected SNPs improve the recently reported genotyping system of cattle.