Results of a nationwide prospective audit of stoma complications within 3 weeks of surgery

OBJECTIVE: Actuarial analysis of stoma complications (problematic stomas) is lacking. The objectives of this audit were: to identify the incidence of stoma complications within the UK; to highlight any dissimilarity of incidence from centre to centre; to ascertain if the height of the stoma (distance of stoma lumen from the skin) at the time of fashioning is a predisposing factor to problems; and finally to initiate much needed research. METHOD: Commencing 1st January 2005, stoma care services nationwide (256) were invited to audit prospectively their next 50 enteric stomas or for a period of 1 year which ever came first. The definition of a problematic stoma being one, which needed one or more accessories to keep the patient clean and dry for a minimum period of 24 h. The incident is to have happened within 3 weeks of surgery. Factors taken into account were: type of stoma, height of stoma within 48 h of surgery; emergency or elective procedure, problem identified, BMI, gender and underlying diagnosis of the patient. The identities of the participating centres are confidential. RESULTS: Of the 256 hospital-based stoma care services within the UK, 93 (36%) participated. A total of 3970 stomas were recorded, of which 1329 (34%) were identified as problematic. Sixty-two centres reported 45-50 stomas with a range of complications 6-96%. The loop ileostomy was found to be the stoma which causes most problems. A stoma of <10 mm is a predisposing factor to complications and problems are more likely to occur following an emergency procedure. More men than women have stomas formed, but have significantly fewer problems and there is no significant difference between underlying diagnoses. CONCLUSION: The stoma height, stoma type and gender of the patient are significant risk factors identified in this audit. The BMI of patient did not affect the outcome. Patients undergoing an emergency procedure are more likely to have a problematic stoma. The significant variation of complications from centre to centre indicates surgical technique as being the key factor in stoma formation and subsequent quality of life for the patient.     

Activation of the respiratory burst in murine phagocytes by certain guanine ribonucleosides modified at the 7 and 8 positions: possible involvement of a pertussis toxin-sensitive G-protein

The capacity of certain guanine ribonucleosides (modified at the 7 and/or 8 positions) to enhance the respiratory burst of murine peritoneal phagocytes was evaluated. The results show that 8-mercaptoguanosine, 8-bromoguanosine, 7-methyl-8-oxoguanosine and 7-thia-8-oxoguanosine, when injected intraperitoneally into mice, induced peritoneal phagocytes to generate reactive oxygen species as early as 1 h after injection. In vivo administration of the nucleosides induced higher levels of phagocyte activation than in vitro treatment with the same nucleosides. However, the addition of interferon alpha/beta in vitro significantly increased the magnitude of phagocyte activation by the nucleosides, suggesting an important role for cytokines/lymphokines in the nucleoside-induced phagocyte activation in vivo. Furthermore, pre-treatment of phagocytes in vitro with Bordetella pertussis toxin, before treatment with the guanosines, inhibited their capacity to induce the respiratory burst. These observations establish these low-molecular-weight compounds as interesting probes for the study of stimulus-response coupling in phagocytes.     

Substituted isoquinolines and quinazolines as potential antiinflammatory agents. Synthesis and biological evaluation of inhibitors of tumor necrosis factor alpha.

A series of isoquinolin-1-ones and quinazolin-4-ones and related derivatives were prepared and evaluated for their ability to inhibit tumor necrosis factor alpha (TNFalpha) production in human peripheral blood monocytes stimulated with bacterial lipopolysaccharide (LPS). In an effort to optimize the TNFalpha inhibitory activity, a homologous series of N-alkanoic acid esters was prepared. Several electrophilic and nucleophilic substitutions were also carried out. Alkanoic acid esters of four carbons were found to be optimum for activity in both the isoquinoline and quinazoline series. Ring substituents such as fluoro, bromo, nitro, acetyl, and aminomethyl on the isoquinoline ring resulted in a significant loss of activity. Likewise, similar groups on the quinazoline ring also reduced inhibitory activity. However, the 6- and 7-aminoquinazoline derivatives, 75 and 76, were potent inhibitors, with IC(50) values in the TNFalpha in vitro assay of approximately 5 microM for each. An in vivo mouse model of pulmonary inflammation was then used to evaluate promising candidate compounds identified in the primary in vitro assay. Compound 75 was selected for further study in this inhalation model, and was found to reduce the level of TNFalpha in brochoalveolar lavage fluid of LPS-treated mice by about 50% that of control mice. Thus, compounds such as 75, which can effectively inhibit proinflammatory cytokines such as TNFalpha in clinically relevant animal models of inflammation and fibrosis, may have potential as new antiinflammatory agents. Finally, a quinazoline derivative suitable to serve as a photoaffinity radiolabeled compound was prepared to help identify the putative cellular target(s) for these TNFalpha inhibitors.     

Risk-adjustment in hepatobiliary pancreatic surgery

AIM: The present study evaluates the performance of the POSSUM, the American Society of Anesthetists (ASA), APACHE and Childs classification in predicting mortality and morbidity in hepatopancreaticobiliary (HPB) surgery. We describe especially the limitations and advantages of risk in stratifying the patients. METHODS: We investigated 177 randomly chosen patients undergoing elective complex HPB surgery in a single institution with a total of 71 pre-operative and intra-operative risk factors. Primary endpoint was in-hospital mortality and morbidity. Ordered logistic regression analysis was used to identify individual predictors of operative morbidity and mortality. RESULTS: The operative mortality in the series was 3.95%. This compared well with the p-POSSUM and APACHE predicted mortality of 4.31% and 4.29% respectively. Postoperative complications amounted to 45% with 24 (13.6%) patients having a major adverse event. On multrvariate analysis the pre-operative POSSUM physiological score (OR = 1.18, P = 0.009) was superior in predicting complications compared to the ASA (P= 0.108), APACHE (P= 0.117) or Childs classification (P= 0.136). In addition, serum sodium, creatinine, international normalized ratio (INR), pulse rate, and intra-operative blood loss were independent risk factors. A combination of the POSSUM variables and INR offered the optimal combination of risk factors for risk prognostication in HPB surgery. CONCLUSION: Morbidity for elective HPB surgery can be accurately predicted and applied in everyday surgical practice as an adjunct in the process of informed consent and for effective allocation of resources for intensive and high-dependency care facilities.     

Noncovalent Modification of Deoxyhemoglobin S Solubility and Erythrocyte Sickling

Ammonium sulfate, as well as potassium phosphate, can be used to measure solubility differences between hemoglobin S and hemoglobin A. In addation, the solubility of deoxyhemoglobin C(Harlem) in 1.96 M phosphate has a markedly different temperature dependence from that of deoxyhemoglobin S. This observation indicates that the solubility measurement is quite sensitive to changes in protein structure. Because of the large degree of comparability between the solubility and the aggregation of deoxyhemoglobin S, solubility was used to measure the effectiveness of organic compounds as noncovalent modifiers of deoxyhemoglobin S aggregation.Organic solvents (ethanol, dimethylsulfoxide, 1,4-dioxane, dimethylformamide) alter the solubility characteristics of deoxyhemoglobin S in 1.96 M phosphate buffer, pH 7.0. The concentrations of solvent necessary to provide a half-maximal effect are remarkably similar (about 0.5 M), although the chemical nature of these compounds is quite different. The effect of these solvents must be to prevent the noncovalent bond formation necessary to produce the insoluble hemoglobin precipitate, perhaps by altering the water structure around the deoxyhemoglobin S molecules. In addition to these organic solvents, guanidine hydrochloride and urea, two well-known protein denaturants, were studied. Guanidine hydrochloride was as effective as the best organic solvent in increasing the solubility of deoxyhemoglobin S; urea was far less effective. Studies in vitro with intact erythrocytes from individuals homozygous for hemoglobin S showed that sickling is decreased up to 50% by treatment with ethanol. This offers further evidence that solubility is monitoring a phenomenon similar to the aggregation of deoxyhemoglobin S inside erythrocytes. While use of these particular compounds in vitro would seem to have no clinical implications, these studies do suggest that the use of chemicals that do not modify hemoglobin S covalently should be explored in efforts to prevent deoxyhemoglobin S aggregation.     

Restoring allosterism with compensatory mutations in hemoglobin.

Abnormal human hemoglobins (HBs) with amino acid substitutions in the alpha 1 beta 2 interface have very high oxygen affinity and greatly reduced cooperativity in O2 binding compared to normal human Hb. In such abnormal Hbs with mutations at position beta 99, the intersubunit hydrogen bonds between Asp-beta 99 and Tyr-alpha 42 and between Asp-beta 99 and Asn-alpha 97 are broken, thus destabilizing the deoxyquaternary structure of these Hbs. A molecular dynamics method has been used to design compensatory amino acid substitutions in these Hbs that can restore their allosteric properties. We have designed a compensatory mutation in a naturally occurring mutant Hb, Hb Kempsey (Asp-beta 99-->Asn), and have produced it using our Escherichia coli expression plasmid pHE2. We have determined the O2 binding properties of this recombinant double mutant Hb, Hb(Asp-beta 99-->Asn and Tyr-alpha 42-->Asp) and have used 1H NMR spectroscopy to investigate the tertiary structures around the heme groups and the quaternary structure in the alpha 1 beta 2 subunit interface. Our results clearly show that the Tyr-alpha 42-->Asp replacement can substantially compensate for the functional defect of Hb Kempsey caused by the Asp-beta 99-->Asn substitution. The structural and functional information derived from this recombinant Hb provides insights into the structural basis of allosterism and the design of compensatory amino acid substitutions to restore the functional properties of other abnormal HBs associated with hemoglobinopathies.     

Matrix metalloproteinase 9 expression in primary human prostatic adenocarcinoma and benign prostatic hyperplasia.

Matrix metalloproteinase (MMP) expression was investigated in patients with prostatic adenocarcinoma and benign prostatic hyperplasia (BPH). Forty-one men were studied: 26 had histologically proven prostate cancer, with 14 (54%) showing metastatic disease; 15 patients had BPH. Prostatic tissue was obtained from transurethral resection and needle core biopsies; gelatinolytic activity was determined by zymography. Seven gelatinolytic bands were detected, with molecular weights ranging from > 100 kilodalton (kDa) to 29 kDa. Nine of 14 patients (64%) with skeletal metastases had 92 kDa activity, present in only two of 12 patients (17%) with a negative bone scan, and absent in BPH. The 92 kDa gelatinolytic activity was expressed in 73% of aneuploid tumours compared with 20% of diploid tumours. A 97 kDa gelatinase was expressed in 80% of BPH samples and 23% of carcinoma patients. Enzyme bands of 72, 66 and 45 kDa were equally expressed in malignant tissue, irrespective of metastatic status, but were expressed in fewer BPH patients. The 97, 92, 66 and 45 kDa enzymes were identified as being pro-MMP-9 sequences by Western blotting, using a specific antibody directed against the pro sequence of the mature protein. MMP activity appeared to be increased in malignant prostatic tissue compared with BPH. Pro-MMP-9, in its 92 kDa form, was shown to be exclusively expressed by malignant prostatic tissue, and in particular by tumours that exhibited the aggressive and metastatic phenotype.     

Effect of Surgically-Induced Weight Loss on Leukocyte Indicators of Chronic Inflammation in Morbid Obesity

Background: Recent evidence suggests that morbid obesity is a chronic inflammatory condition that may be associated with immune dysfunction.To test this hypothesis, we investigated several leukocyte cell surface markers of chronic inflammation and followed their response to surgically-induced weight loss. Methods: 26 patients having Roux-en-Y gastric bypass (RYGBP) for morbid obesity (BMI>40) were compared to 10 normal controls (BMI<25). Relative monocyte and neutrophil frequencies and expression of the activation antigens CD11b (adhesion molecule), CD16 (Fc receptor), and CD62L (Lselectin), were evaluated by flow cytometry preoperatively and at 1, 3, 6 and 12 months after RYGBP. Cases served as their own controls but were also compared to non-obese controls. The results were statistically analyzed using Student's t-test and ANOVA for parametric values and Mann-Whitney along with Kruskal-Wallis ANOVA for nonparametric values Results: The control group had mean age 37 ± 7.6 with mean 23 ± 2.5 and no comorbidities. The mean age of the sample group was 40.36 ± 13.7 with mean BMI 52 ± 8.2. The neutrophil and monocyte relative frequencies of CD11b (monocytes and neutrophils), and CD16 (neutrophils only) were comparable to controls at baseline and did not change significantly with weight loss throughout the study period. However, a significant reduction of CD62L (Lselectin) expression was noted in monocytes and neutrophils at baseline (neutrophils 103 vs 240 gmf, p<0.001) (monocytes104 vs 246 gmf, P<0.001) when compared to normal controls. Levels of L-selectin normalized by 6 months in both monocytes and neutrophils, and by 12 months had become abnormally elevated in monocytes (monocytes 391 gmf, P=0.007); in neutrophils, there was an upward trend that did not reach significance.The expression of the LPS receptor CD14 in the study group was elevated significantly compared to controls at baseline (1129 vs 719 gmf, P=0.004); this marker appeared to return to normal by 3 months. Monocyte CD14+/CD16+ subset percentage were also elevated significantly at baseline (14.3% vs 5.25%, P <0.001), declined throughout the time period but was still significant at 1 year (8.8%, P<0.001). Eosinophil percentages were elevated at baseline (3.3% obese vs 1.8% controls, P=0.003) and remained so throughout the time period. Conclusion: Deficiencies in the immune system of morbidly obese individuals include elevated levels of eosinophils, monocyte CD14, and monocyte CD14+/CD16+ subsets, with depression of monocyte and neutrophil CD62L. These abnormal levels reverse rapidly with surgically-induced weight loss. RYGBP is not only a weight loss operation but also appears to be an immune restorative procedure.     

The impact of laparoscopy on bariatric surgery

The rising popularity of bariatric surgery over the past several years is attributable in part to the development of laparoscopic bariatric surgery. Morbidly obese patients have associated comorbid conditions that may predispose them to postoperative morbidity. The laparoscopic approach to bariatric surgery offers a minimally invasive option that reduces the physiologic stress and provides clinical benefits, as compared with the open approach. This review summarizes the impact of laparoscopic surgery on bariatric surgery, the various risk factors that could potentially predispose morbidly obese patients to postoperative morbidity, the fundamental differences between laparoscopic and open bariatric surgery, and the physiology of reduced tissue injury associated with laparoscopic bariatric surgery.