Complexity in seemingly simple sodium magnesiate systems.

A systematic study both in the solid- and solution-state, was carried out for a series of sodium magnesiates containing the utility amide ligand 1,1,1,3,3,3-hexamethyldisilazide (HMDS). The first complex considered is the donor-free bisamido monoalkyl polymeric complex [Na(µ-HMDS)2Mg((n)Bu)]∞ 1. The reactivity of 1 with common tertiary bidentate donors including N,N,N',N'-tetramethylethylenediamine (TMEDA) or its chiral relative (1R,2R)-tetramethylcyclohexyldiamine [(R,R)-TMCDA] is detailed. Surprisingly, the products of these reactions are not simple diamine adducts but are solvent separated sodium magnesiate systems [(TMEDA)2·Na](+)[Mg(HMDS)3](-) 2 and [{(R,R)-TMCDA}2·Na](+)[Mg(HMDS)3](-) 3. By concentrating on the likely equilibria which may give rise to formation of 2, a potential intermediate complexed ion pair [{(TMEDA)2·Na}(µ-(n)Bu)Mg(HMDS)2] 4 was isolated. Additionally, the novel "inverse magnesiates" [{Na(µ-HMDS)}2Mg(µ-(n)Bu)2·(TMEDA)]∞ 5 and [{Na(µ-HMDS)}2Mg(µ-(n)Bu)2·{(R,R)-TMCDA}]∞ 6, were obtained by reacting solutions of composition "NaMg(HMDS)((n)Bu)2" (a likely by-product in the formation of 2 from 1), with TMEDA or (R,R)-TMCDA. The structure and nature of these bimetallic complexes have been determined using a combination of X-ray crystallographic studies and multinuclear NMR spectroscopy.

Predictors of outcome in palliative colonic stent placement for malignant obstruction.

BACKGROUND: Emergency surgery for large bowel obstruction carries significant morbidity and mortality. After initially promising results, concerns have been raised over complication rates for self-expandable metal stents (SEMS) in both the palliative and bridge-to-surgery settings. This article documents the technique used at the authors' institution, and reports on success and complication rates, as well as identifying predictors of endoscopic reintervention or surgical treatment. METHODS: Data were collected for a prospective cohort of consecutive patients undergoing attempted colonoscopic SEMS insertion at a single institution between 1998 and 2013. Multivariable logistic models were fitted to assess possible predictors of endoscopic reintervention and surgical treatment. RESULTS: Palliative SEMS insertion was attempted in 146 patients. Primary colorectal cancer was the most common cause of obstruction (95.2 per cent). The majority of patients (77.4 per cent) were treated in an acute setting, with a high technical success rate of 97.3 per cent. The perforation rate was 4.8 per cent and the 30-day procedural mortality rate 2.7 per cent. No predictors of early complications were identified, although patients with metastases and those who received chemotherapy were more likely to have late complications. Some 30.8 per cent of patients required at least one further intervention, with 11.0 per cent of the cohort requiring a stoma. Endoscopic reintervention was largely successful. CONCLUSION: SEMS offer a valid alternative to operative intervention in the palliative management of malignant large bowel obstruction. Patients receiving chemotherapy are more likely to receive endoscopic reintervention, which is largely successful.

The process and outcomes of a nurse-led colorectal cancer follow-up clinic.

AIM: Evidence suggests that follow-up after colorectal cancer improves survival. Colorectal cancer is so common that patient follow-up can overwhelm a service, affecting the ability to see new referrals and reassess patients seen previously who have new symptoms. In order to cope with this demand a nurse-led follow-up service was started in 2004. We aimed to review the results of a nurse-led colorectal cancer follow-up clinic. METHOD: Between 1 December 2004 and 31 January 2011, patients who underwent resection for colorectal cancer were followed up by a nurse specialist according to a protocol determined by the colorectal surgeons in the unit. All patient details were recorded prospectively in a purpose designed database. RESULTS: Nine hundred and fifty patients were followed up over 7 years. Some 368 patients were discharged from the follow-up programme, 474 patients remain actively involved in the programme and 108 patients died. Of the patients discharged from the follow-up scheme 269 (73%) were discharged to their general practitioner free of disease after 5 years. Of the 108 who patients died, 98 were as a result of colorectal cancer. Twenty patients (2.1%) were identified with local (peri-anastomotic) disease recurrence and 93 patients (9.8%) were found to have developed distant metastatic disease. Of these, 65 patients (6.8%) were referred for palliative care and 28 (2.9%) had surgery for focal metastatic disease of whom 18 were still alive at the time of this analysis. CONCLUSION: This paper shows that a nurse-led clinic for colorectal cancer follow-up can achieve satisfactory results with detection rates of recurrent or metastatic disease comparable to consultant follow-up. A nurse-led clinic provides the benefits of follow-up without overwhelming the consultant colorectal surgical clinic practice.

The role of positron emission tomography in the management of recurrent colorectal cancer: a review.

PURPOSE: Surgery remains the only option for potential cure in patients with recurrent colorectal cancer. Accurate staging modalities aid in the avoidance of futile surgery, which may result in considerable morbidity in patients with incurable disease. Current imaging techniques used in disease staging often are not sensitive enough to identify low-volume metastatic disease. This study reviews the role of positron emission tomography in the assessment of patients with suspected recurrent colorectal cancer. METHODS: A literature search using the PubMed, MEDLINE, and Embase database was performed, locating English language articles on positron emission tomography, positron emission tomography, recurrent colon, and/or rectal cancer. The references of these papers were searched manually for further references. RESULTS: Positron emission tomography is more sensitive and more specific than conventional diagnostic imaging for metastatic disease and local recurrence respectively. Studies confirm the superior ability of positron emission tomography scans compared with conventional diagnostic imaging in differentiating between scar tissue and invasive tumor. Positron emission tomography scanning is more sensitive and specific for the assessment of liver metastases (and probably in patients with lung metastasis) than conventional diagnostic imaging. Positron emission tomography is superior to conventional diagnostic imaging in the investigation of raised carcinoembryonic antigen in the postoperative patient and alters management in approximately 37 percent of patients with recurrent colorectal cancer. The limitations and cost effectiveness of positron emission tomography are discussed. CONCLUSIONS: Positron emission tomography scanning is emerging as the imaging modality of choice for patients being considered for surgery for locally recurrent colorectal cancer. Positron emission tomography has the greatest impact by detecting unresectable disease and thereby averting inappropriate surgery. Despite the high set-up costs, its use seems to be cost effective.

Parastomal hernia.

BACKGROUND: Parastomal hernia following formation of an ileostomy or colostomy is common. This article reviews the incidence of hernia, the technical factors related to the construction of the stoma that may influence the incidence, and the success of the different methods of repair. METHODS: A literature search using the Medline database was performed to locate English language articles on parastomal hernia. Further articles were obtained from the references cited in the literature initially reviewed. RESULTS: Parastomal hernia affects 1.8-28.3 per cent of end ileostomies, and 0-6.2 per cent of loop ileostomies. Following colostomy formation, the rates are 4.0-48.1 and 0-30.8 per cent respectively. Site of stoma formation (through or lateral to rectus abdominis), trephine size, fascial fixation and closure of lateral space are not proven to affect the incidence of hernia. The role of extraperitoneal stoma construction is uncertain. Mesh repair gives a lower rate of recurrence (0-33.3 per cent) than direct tissue repair (46-100 per cent) or stoma relocation (0-76.2 per cent). CONCLUSION: The incidence of parastomal hernia is between 0 and 48.1 per cent, depending on the type of stoma and length of follow-up. No technical factors related to the construction of the stoma have been shown to prevent herniation. If repair is required, a prosthetic mesh technique should be considered. Further randomized clinical trials (particularly of extraperitoneal stoma construction) are needed.

The utility of laparoscopy in the diagnosis of acute appendicitis in women of reproductive age.

AIM: To see whether laparoscopy improves the accuracy of a clinical diagnosis of acute appendicitis in women of reproductive age, and to determine what the long-term sequelae are of not removing an appendix deemed at laparoscopy to be normal. METHOD: The initial part of the study was undertaken during 1991-1992. Female patients between 16 and 45 years were eligible for inclusion once a clinical decision had been made to perform an appendicectomy for suspected acute appendicitis. Following consent, patients were randomized into two groups. One group had open appendicectomy, as planned. The other group had laparoscopy, followed by open appendicectomy only if the appendix was seen to be inflamed or was not visualized. The end points for the study were the clinical outcomes of all patients, and the results of histology, where appropriate. An attempt was made to contact all patients at 10 years to determine whether they had had a subsequent appendicectomy, or had been diagnosed with another abdominal condition that might be relevant to the initial presentation in 1991-1992. RESULTS: Laparoscopic assessment was correct in all cases in which the appendix was visualized. Diagnostic accuracy was improved from 75% to 97%. Laparoscopy was associated with no added complications, no increase in hospital stay in patients who went on to appendicectomy, and a reduction in hospital stay for those who underwent laparoscopy alone. No patients developed a problem over the 10-year follow-up period from having a normal-looking appendix not removed at laparoscopy. CONCLUSION: Laparoscopic assessment of the appendix is reliable, and to leave a normal-looking appendix at laparoscopy does not appear to cause any long-term problems.

Management of late complications of pelvic radiation in the rectum and anus: a review.

PURPOSE: Radiotherapy has become one of the most important treatment modalities for human malignancy. Tumors affecting the organs of the pelvis are increasingly being irradiated for local treatment benefit, with the subsequent complication of anorectal injury of varying extent. The aim of this review is to determine how to manage the consequences of long-term effects of radiotherapy on the rectum and anus. METHODS: A comprehensive search of the literature with manual cross-referencing was performed using the MEDLINE, PubMed, and Cochrane Databases. RESULTS: Long-term manifestations of injury caused by pelvic radiotherapy include abscess and fistula formation, stricture, mucus discharge, urgency, tenesmus, diarrhea, increased risk of cancer, and most commonly, bleeding. Most patients present with several symptoms; however, usually one symptom dominates. CONCLUSIONS: Many of these symptoms are self-limiting, and mucosal complications may often be treated by nonsurgical methods such as topical formalin application, endoscopic argon plasma coagulation, and hyperbaric oxygen therapy. Conservative measures have not been shown to be of benefit if symptoms persist. Structural abnormalities and septic complications are likely to require surgery. Modern techniques in the delivery of radiotherapy help minimize the likelihood of rectal complications.

Vaccine efficacy for reducing turbinate atrophy and improving growth rate in piggeries with endemic atrophic rhinitis.

Two vaccines, based on formalin-killed whole cells of toxigenic Pasteurella multocida type D and Bordetella bronchiseptica combined with a partially toxoided cell extract of P multocida, were prepared with Freund's incomplete adjuvant (vaccine 1) or by alum precipitation (vaccine 2). Each was tested for safety and efficacy in reducing the severity of nasal turbinate atrophy and improving the growth rate of pigs in three Western Australian commercial piggeries with endemic atrophic rhinitis. In safety experiments with vaccine 1, no adverse clinical effects were observed in vaccinated sows or their progeny. Piglets receiving vaccine 2 showed no injection site abnormalities, pyrexia or turbinate atrophy. In field trials, vaccine 1 significantly reduced the prevalence of moderate to severe nasal turbinate atrophy (Done score 3 to 5) when used in two piggeries (A and B). Progeny from vaccinated sows in piggery B also grew significantly faster than controls. When vaccine 2 was used in piggery A at a later date and in another piggery (C), growth rate was not improved in either piggery and the prevalence of moderate to severe turbinate atrophy was reduced only in piggery C.

Use of the enzyme linked immunosorbent assay (ELISA) to detect the IgM and IgG antibody response to Leptospira interrogans Serovar hardjo in pregnant ewes.

Fourteen pregnant ewes were inoculated with Leptospira interrogans serovar hardjo via intramuscular injection or inoculation via the conjunctiva. The serological response to inoculation detected by the microscopic agglutination test was compared to IgM and IgG antibody levels detected by enzyme linked immunosorbent assay. Intramuscular injection produced a better serological response than conjunctival inoculation. The mean IgM response was short lived whereas the IgG antibody response and the MAT persisted for much longer. The IgM antibody levels may be useful as an indicator of recent exposure. Although leptospiruria was not established in any of the animals, 6 of the 14 pregnant ewes failed to rear a healthy lamb.

Vaccination against ovine dermatophilosis.

Zoospore, filamentous and soluble antigens were prepared from Dermatophilus congolensis and examined for their ability to protect sheep from challenge with D. congolensis zoospores. In 1 experiment, sheep were vaccinated with Antigens A, B and C. The number of sheep protected in the group vaccinated with Antigen B was greater (P less than 0.05) than that in the unvaccinated group after challenge. The group vaccinated with Antigen B had a higher antibody response (P less than 0.05) to Antigen B than to Antigen A or C. In a second experiment, 2 groups of sheep were vaccinated with Antigen B. All sheep in this study developed lesions after challenge, but those on the vaccinated sheep were less severe (P less than 0.05) than those on the unvaccinated sheep. The antibody response to Antigen A, 28 days after vaccination, was higher (P less than 0.05) than the response to Antigen B.

Serum and skin surface antibody responses in merino sheep given three successive inoculations with Dermatophilus congolensis.

Three antigens prepared from different phases of the life cycle of Dermatophilus congolensis were used in an enzyme-linked immunosorbent assay to measure serum and skin surface antibody responses in sheep after a first, second and third inoculation with D. congolensis. After the first inoculation, a strong antibody response to the flagella, filament and soluble antigens was detected after 7-21 days in the sera from sheep that were regularly biopsied; the antibody response at the skin surface was detected 28-42 days after inoculation, when the lesions were resolving. Strong anamnestic responses were detected in the serum of sheep that were biopsied and some of the nonbiopsied sheep after the second and third inoculations, but the skin surface antibody response at these times was variable.

Cellular responses in the skin of merino sheep to repeated inoculation with Dermatophilus congolensis.

The cellular response in the skin of Merino sheep was examined after three successive inoculations with Dermatophilus congolensis. There was a massive neutrophil influx into the infected epidermis and underlying dermis at 4-10 days after the first inoculation. A lymphocyte-macrophage response occurred at 10-12 days, followed by a plasma cell response at 14-38 days. Resolution of skin lesions after the first inoculation corresponded to the time when the plasma cell response in the skin was most intense. A second inoculation with D. congolensis, 70 days after the first, failed to produce skin lesions typical of dermatophilosis. Typical lesions of dermatophilosis did develop after a third inoculation of the same sheep 140 days after the first inoculation, but the lesions resolved in most sheep within 13 days. Dermatophilosis did not develop in some of these sheep at sites inoculated with 100-1000-fold lower infective doses of D. congolensis, whereas control sheep did develop lesions.

Isolation of toxigenic Pasteurella multocida from an outbreak of atrophic rhinitis in pigs.

An outbreak of severe atrophic rhinitis is described. A toxigenic strain of P. multocida was isolated from one affected pig. Severe turbinate atrophy was not associated with significantly reduced bodyweight gain in a batch of 34 pigs examined at slaughter. The history of the outbreak suggested that pigs recently introduced from overseas may have been the source of the disease.

Use of enzyme immunoassay in a serological survey of leptospirosis in sheep.

A total of 731 serums, all from Merino rams from 20 farms, were tested for antibodies against Leptospira interrogans serovars hardjo, pomona and tarassovi using the microscopic agglutination test (MAT). The enzyme immunoassay (EIA) technique was used to test all serums for IgM and IgG antibodies to serovar hardjo. In the MAT, reactions to serovar hardjo were most common with 236 rams (32.3%) reacting at 1/100 or greater. Only 1.9% of serums reacted against serovar tarassovi and 1.1% against serovar pomona. The percentage of sheep with positive MAT reactions to serovar hardjo ranged from 0 0 to 94.9 between farms. When using EIA, 46 (6.2%) of the serums were positive for IgM antibody and 246 (33.6%) were positive for IgG antibody. Correlation of the EIA for detection of IgG antibody with the MAT was good. The EIA detection of IgG antibody was considered to be a good alternative test to the MAT for epidemiological studies in sheep.

The use of the enzyme-linked immunosorbent assay (ELISA) to detect the IgM and IgG antibody response to Leptospira interrogans serovars hardjo, pomona and tarassovi in cattle.

Leptospira interrogans serovars pomona, hardjo and tarassovi were each used to inoculate 6 cattle. Three-hundred and ninety-nine sera collected from the inoculated animals and from a control group over a 3-month period were tested using the microscopic agglutination test (MAT) and the enzyme-linked immunosorbent assay (ELISA). Leptospiruria was monitored by microscopic examination and culture. The ELISA detected specific IgM antibody against the serovars in all infected cattle 1 week after inoculation. This IgM antibody persisted in most of the animals for 3-5 weeks. Specific IgG antibody appeared at the same time or just after IgM, but persisted for much longer. Levels of antibody detected by the ELISA and the MAT did not correlate with each other, nor with the periods of leptospiruria found in the infected cattle.