Intra- and extracellular modifications of apolipoproteins.

This chapter outlined the methods used to study intra- and extracellular modifications of apolipoproteins. These and other related studies have shown that several of the apolipoproteins undergo a series of intra- and extracellular modifications as follows: All apolipoproteins studied contain an 18-26 long signal peptide which is cleaved cotranslationally by the signal peptidase of the rough endoplasmic reticulum. ApoE is further modified intracellularly with carbohydrate chains containing sialic acid and is secreted in the modified form designated apoEs. The modified apoE is subsequently desialated in plasma. ApoA-I is secreted in a proapoA-I form, which consists of 249 amino acids. The N-terminal hexapeptide of proapoA-I is cleaved extracellularly by a proapoA-I to plasma apoA-I converting protease. This cleavage generates the plasma apoA-I form which consists of 243 amino acids. Other known apolipoprotein modifications include the modification of apoB, apoC-III, and apoD with carbohydrate chains that contain sialic acid and the proteolytic cleavage of the proapoA-II segment. At the present time we are able to distinguish several isoprotein forms for a particular apolipoprotein. In addition, we began to understand the biochemical changes which lead to a few of these isoproteins. Future research should be directed toward a better understanding not only of the structure but most importantly of the physiological significance of the different apolipoprotein forms.

Serum F protein estimation in liver allograft recipients with graft dysfunction.

Serum levels of F protein, a 44 kD cytoplasmic protein mainly found in hepatocytes, became elevated during episodes of graft dysfunction following orthotopic liver transplantation. In a study of 27 liver transplant recipients, the rise in F protein did not precede rises in the other conventional biochemical indices of hepatic dysfunction. Serum F protein concentration significantly correlated with serum levels of aspartate aminotransferase, gamma-glutamyltransferase, alkaline phosphatase, and bilirubin (all P less than 0.001) and also with the prothrombin time (P = 0.048). Despite its high concentration in liver cells, this marker does not provide any additional benefit in the diagnosis of graft dysfunction or in monitoring liver allograft function following transplantation.

Intestinal mucosal mononuclear cell chimaerism after sex-mismatched allogeneic bone marrow transplantation.

The contribution of haemopoietic cell chimaerism to the pathogenesis of GVHD after BMT is unclear. This report raises the possibility that donor lymphocyte-recipient macrophage chimaerism may occur shortly after allogeneic marrow engraftment and hence might contribute to the development of GVHD. Immunohistological studies of intestinal mucosa in an allogeneic BMT patient, who did not engraft, revealed an almost complete absence of lymphocytes 30 days after transplant, but preservation of mucosal macrophage numbers. Subsequently, combined immunohistology-Y chromosome in situ hybridization studies were performed in two female BMT recipients of male donor marrow. These studies revealed that between 25 and 40% of macrophages and between 25 and 40% of T lymphocytes were of donor origin during the first 6 months after transplant. In conclusion, whilst the immunohistological studies of intestinal mucosa from a patient who failed to engraft suggest that donor lymphocyte-recipient macrophage ('split') chimaerism may occur shortly after marrow engraftment, the subsequent in situ hybridization studies revealed 'mixed' chimaerism in the two sex-mismatched BMT recipients.

Immunohistochemical changes in sigmoid colon after allogeneic and autologous bone marrow transplantation.

AIM: To determine whether there are characteristic immunohistological changes in the colonic mucosa in acute graft versus host disease (GvHD). METHODS: Consecutive allogeneic (n = 11) and autologous (n = 11) bone marrow transplant recipients underwent endoscopic biopsy of sigmoid mucosa before transplant and on day 30 post-transplant. Immunohistochemical staining and quantitation of intraepithelial and lamina propria mononuclear cells were undertaken using a panel of monoclonal antibodies and a Streptavidin-biotin alkaline phosphatase staining technique. RESULTS: In the allogeneic group (nine of whom had clinical acute GvHD) there was a fivefold increase in lamina propria CD16+ mononuclear cells (3.1 +/- 4.3 to 17.0 +/- 12.2 per 100 lamina propria nucleated cells), compared with autologous transplant recipients in whom this rise was twofold (5.5 +/- 4.6 to 10.6 +/- 7.1 per 100 lamina propria nucleated cells). The CD16+ mononuclear cells had morphological appearances of tissue macrophages, but in neither the allogeneic nor autologous groups was there an increase in total macrophage numbers (CD14+). In patients with acute GvHD the lamina propria CD4+:CD8+ lymphocyte ratio fell (1.97 +/- 1.12 to 1.07 +/- 1.01), primarily because of a fall in the number of lamina propria CD4+ lymphocytes. In both allogeneic and autologous groups there was a fall in intraepithelial lymphocyte numbers, but there was no change in CD19+ (B cell), CD25+ (interleukin-2 receptor positive) or CD56+ (natural killer) cell numbers. CONCLUSION: Following bone marrow transplantation, there appears to be upregulation of lamina propria tissue macrophage CD16 (an Fc receptor for IgG), a change which is more noticeable after allogeneic transplantation and which may be related to the development of acute GvHD. In patients with acute GvHD there was a fall in the lamina propria CD4+:CD8+ lymphocyte ratio. If these changes are functionally important, they may have significant implications for understanding the pathogenesis of GvHD.

Ultrastructural evidence of intestinal mucosal macrophage activation after bone marrow transplantation.

Previous studies have demonstrated upregulation of intestinal mucosal macrophage CD16 (an Fc receptor for IgG) in bone marrow transplant (BMT) recipients with graft-versus-host disease (GVHD). We sought to determine whether there was ultrastructural evidence of mucosal macrophage activation in allogeneic BMT recipients and relate appearances to those seen in autologous BMT patients and to immunohistological findings. Sigmoid colonic mucosal biopsies from five allogeneic and three autologous BMT patients were taken prior to, 30 days after transplant and, in three of the allogeneic patients, 120 days after transplant. These were examined by immunohistochemistry and electron microscopy. Immunohistological analysis revealed upregulation of lamina propria macrophage CD16 after transplant in all patients except one autologous BMT recipient; there were no such changes in total macrophage numbers. Ultrastructural evidence of lamina propria macrophage activation was prominent after both allogeneic and autologous BMT. There was an increase in nuclear size accompanied by increased euchromatin and larger nucleoli. In the cytoplasm there were increased numbers of lysosomes, many of which were small and cylindrical, and cytoplasmic flaps were prominent. Phagosomes were less numerous after transplant. These data confirm that after BMT intestinal mucosal macrophages become activated. However changes in macrophage ultrastructure specific to patients at risk of developing clinical GVHD are lacking.

Proteome analysis of Helicobacter pylori: major proteins of type strain NCTC 11637.

Proteome analysis involves the simultaneous resolution and display of proteins produced by an organism, followed by the quantitation, characterisation and identification of these proteins. As part of an ongoing study mapping and comparing the proteins expressed by various strains of the pathogenic bacterium Helicobacter pylori, we have resolved and identified 93 of the most abundant proteins expressed by type reference strain NCTC 11637. Proteins were separated by two-dimensional gel electrophoresis and stained with Coomassie G250. Intensely-stained spots were excised and digested with trypsin, and the resulting peptides were characterised by mass spectrometry. Proteins were then identified by correlating actual peptide profiles with theoretical profiles generated from published nucleotide sequences. Ninety-three of the most intensely-stained protein spots were identified as the products of 35 genes, giving a ratio of 2.7 protein gene-products per gene. The products of the tsaA, pfr, ureA and ureB genes were amongst several proteins present in multiple isoforms. Peptide mass fingerprinting data were used to identify probable post-translational protein modifications. These results suggest that H. pylori proteins are subject to a high degree of post-translational modification. Comparative proteomics of H. pylori strains should greatly assist in investigating the pathogenic properties of this bacterium.

Detection of Helicobacter pylori antigen in faeces by enzyme immunoassay.

The detection of Helicobacter pylori antigen directly in faecal specimens may offer an alternative non-invasive method for determining the presence of H. pylori infection. This study compared the performance of the Premier Platinum HpSA enzyme immunoassay (HpSA) with histology and CLOtest, a rapid urease test. Of 134 patients undergoing upper gastrointestinal endoscopy, 37 (28%) were H. pylori-positive by histology and CLOtest. Using the HpSA test, H. pylori was detected in 35 H. pylori-positive patients (95% sensitivity) and one H. pylori-negative patient (99% specificity). The positive and negative predictive values for HpSA were 97 and 98%, respectively. HpSA is a rapid, easily performed, non-invasive method for detecting H. pylori.

Nocardiosis in liver transplantation: variation in presentation, diagnosis and therapy.

Nocardiosis arose in seven of 191 liver transplant patients (3.7%) over a period of 3.5 years. Four patients had only pulmonary lesions while three had disseminated disease. Nocardia asteroides was isolated from three patients following bronchoscopy, percutaneous aspirate of a pulmonary lesion in one patients, and from the skin from the aspirates in three patients. Delay in diagnosis in two cases was due to negative microscopy; in one, the diagnosis was made only after repeated bronchoscopy. Of the seven patients, three (43%) died. In two of these, nocardiosis was considered to have directly contributed to death. Co-existent bacterial and viral infections were present in all patients who died. In vitro susceptibility of the organism to co-trimoxazole was variable and did not necessarily reflect clinical efficacy. In one patient, a good clinical response was achieved with co-trimoxazole despite apparently reduced in vitro susceptibility.

Micronutrient status in patients receiving home parenteral nutrition.

Administration of home parenteral nutrition (HPN) to patients with intestinal failure requires attention to caloric content of feeds, fluid, electrolyte balance, and micronutrient status. Peripheral blood estimations of vitamins and trace elements may be abnormal, but their clinical significance in relation to deficiency or toxicity states is not always clear. We sought to determine the incidence and nature of clinical micronutrient abnormality in our HPN program. Clinical assessment and case record review of 49 patients actively receiving HPN was undertaken, and, in 32 of these patients, serum micronutrient levels were assayed. Clinical evidence of micronutrient deficiency was identified in 16 patients (33%). Iron deficiency anemia occurred in 14 patients which resolved after iron supplementation in all except 1 patient who had persistent intestinal blood loss. Anemia was precipitated in six patients by identifiable clinical events (acute gastrointestinal disease in five and menorrhagia in one), and in two others folate deficiency coexisted. Biotin deficiency developed in three patients, manifested by dry eyes and angular cheilitis or hair loss. Vitamin A deficiency resulting in visual disturbance developed in one patient who was not receiving multivitamin supplements at that time. Serum levels of zinc, copper, selenium, manganese, vitamin A, and vitamin E were measured in 32 patients. No patient had normal levels of all six micronutrients. Nevertheless, there was no clinical evidence of toxicity or deficiency in any of these patients at the time assays were performed. In conclusion, abnormalities of micronutrient status are common in HPN patients, but serious sequelae appear to be unusual.

Prospective study of the quality of life in patients assessed for liver transplantation: outcome in transplanted and not transplanted groups.

The quality of life in adult patients with chronic liver disease who were considered for transplantation was assessed prospectively over a 2 year period, for both those who did and did not subsequently receive transplants. The main outcome measures were the Nottingham Health Profile and survival. Of the 109 patients who completed an entry profile, 27 were transplanted, 71 not transplanted during the study period, and 11 rejected for transplant. Quality of life and severity of liver disease at entry was worse for the transplant group, whose survival at 15 months from entry was 81% compared with 78% for those not transplanted. Among transplant survivors there were marked improvements in quality of life, whilst amongst those not receiving transplants there was little change. In conclusion, liver transplantation was effective in improving quality of life in patients with chronic liver disease, but comparison between transplant and non-transplant patients is difficult because of differences between the groups.

Computed tomography colonography.

Computed tomography colonography (virtual colonoscopy) is an exciting technique that continues to evolve but promises to be a valuable tool for diagnosis of and screening for colorectal neoplasia.

The behaviour of preschool children receiving fluoride varnish application in a community setting.

BACKGROUND: The behaviour of young children receiving mildly invasive dental preventive procedures in a community setting warrants more extensive research due to limitations in the literature.Objectives To document the behavioural profile of preschool children undergoing a preventive oral health intervention (fluoride varnish application) and to investigate this behaviour across children with different previous experience of the procedure, ages and initial anxiety states. METHOD: Nurse-child interactions were video recorded and child behaviours coded and analysed using a specially developed coding scheme (SABICS). Behaviour frequency was measured and presented diagrammatically, followed by independent sample non-parametric tests to distinguish behavioural group differences. RESULTS: Three hundred and three interactions were coded out of 456 recorded application sessions. 'Nonverbal agreement' behaviour was observed most frequently compared to disruptive behaviours. Younger preschool children tended to exhibit 'interact with instrument' behaviour more frequently than older children regardless of whether they had had previous application experience. Children who showed signs of initial anxiety were likely to display more disruptive behaviours during the later stage of the procedure compared with non-anxious children. CONCLUSIONS: Dental staff working with preschool children are recommended to use encouragement-centred strategies to promote nonverbal cooperative behaviours in children. In addition, procedure instruments could be considered as a tool to gain child cooperation. Evidence of an autocorrelation effect of child behaviour was found, indicating that the early presentation of child behaviour predicted the behaviour of the child at later stages.

The behaviour of extended duties dental nurses and the acceptance of fluoride varnish application in preschool children.

BACKGROUND: Extended duties dental nurses (EDDNs) have been trained to deliver fluoride varnish applications to preschool children as part of the Childsmile initiative in Scotland. OBJECTIVES: To determine a detailed behavioural profile of the EDDNs during the administration of the fluoride varnish to confirm professional manner and identify differences in nurse behaviours between successful and unsuccessful application sessions. METHODS: Nurse-child interactions were video recorded and nurse behaviours coded and analysed using a specially developed coding scheme (SABICS). Behaviour frequency and duration were measured and correlations were calculated. Differences in behaviour were examined between successful and unsuccessful application sessions. RESULTS: Three hundred and three interactions were coded out of 456 recorded application sessions. No incident occurred where nurses threatened or placed undue stress on a child. In unsuccessful, compared with successful, application sessions, nurses demonstrated higher frequency and duration of the following behaviours: 'permission seeking', 'offer of task alternative', 'information seeking' and 'reassurance', controlling for length of procedure. Whereas with successful applications, 'praise', 'instruction' and 'information-giving' were used more frequently and for a longer duration, compared with unsuccessful applications. CONCLUSIONS: The EDDNs demonstrated a professional manner working with preschool children. They behaved differently between successful and unsuccessful application sessions. Sequential analysis is needed to examine causal effects of behaviours and its effects on delivery outcomes.

Randomized single blind trial of two low-volume bowel preparations for screening computed tomographic colonography.

BACKGROUND: Bowel preparation is an important part of computed tomographic colonography (CTC); we evaluated two small-volume preparations for screening CTC with regard to quality of preparation and patient acceptability. METHODS: Asymptomatic subjects at average risk for colorectal cancer from a community-based CTC screening program were randomized to bowel preparation comprising magnesium/bisacodyl/picolax or polyethylene glycol (PEG)/picolax. CTC images were evaluated by a blinded investigator for residual feces and fluid; subjects completed a questionnaire regarding acceptability of the preparation. RESULTS: In 176 subjects randomized to magnesium/bisacodyl/picolax (n = 82) or PEG/picolax (n = 94), the former preparation was discontinued because of syncope or presyncope in four (5%) subjects. Another 137 subjects received PEG/picolax without a significant adverse event. There were no other major differences in acceptability of the preparations as reported by subjects. The quality of bowel preparations for reporting CTC was similar. CONCLUSION: For subjects having screening CTC, both small-volume bowel preparations are generally well tolerated and result in minimal fluid and fecal residue; however, the magnesium/bisacodyl/picolax preparation was accompanied by an unacceptable incidence of syncope and is no longer used by us.

Review: Helicobacter pylori. Current issues and new directions.

The present review outlines current management issues and controversies related to Helicobacter pylori infection. Clearance of this infection markedly reduces the likelihood of duodenal and gastric ulcer recurrence and may result in the regression of low grade primary gastric lymphoma. Recent therapeutic advances have seen the development of simpler drug regimens to treat H. pylori that have fewer side effects and are shorter in duration. Clearance of the infection can be achieved in 80-95% of patients treated, depending on the drug regimen used, compliance with medications and antibiotic sensitivity. In developed nations reinfection is uncommon after successful treatment. Data do not currently support treatment of this infection for non-ulcer dyspepsia or for the prevention of gastric cancer, although whether certain individuals or populations may benefit from such treatment remains to be clarified.

Primary cerebral lymphoma: an association with craniopharyngioma or cadaveric growth hormone therapy?

OBJECTIVES: To present the first case of primary cerebral lymphoma associated with craniopharyngioma or previous cadaveric growth hormone therapy. CLINICAL FEATURES: A 22-year-old male shop assistant of European descent presented with unilateral uveitis and was found to have a high grade primary cerebral lymphoma. This occurred nine years after successful surgical resection of a craniopharyngioma without the administration of adjuvant radiotherapy. INTERVENTION AND OUTCOME: There was initial radiological resolution of cerebral lymphoma after cranial irradiation. Recurrence was noted 10 weeks later, resulting in the patient's death. CONCLUSION: The development of primary cerebral lymphoma following a craniopharyngioma is considered most likely a chance occurrence. Cadaveric growth hormone therapy may play a role in the genesis of lymphoma.

Nitrous oxide for colonoscopy: a randomized controlled study.

BACKGROUND: Intravenous sedation/analgesia for colonoscopy is accompanied with certain risks and postprocedure drowsiness. We sought to determine whether inhaled nitrous oxide (Entonox: 50% nitrous oxide, 50% oxygen) provides adequate analgesia for colonoscopy and the impact of this agent on recovery. METHODS: All patients undergoing outpatient colonoscopy were considered for the study (n = 248) except those with previous colonic resection. Data for patients unsuitable for randomization (n = 58) and those who declined to participate (n = 88) were also analyzed. RESULTS: One hundred two patients were randomized to receive inhaled Entonox alone (n = 56) or intravenous midazolam and meperidine (n = 46). Forty-nine (88%) patients randomized to Entonox underwent complete colonoscopy without conversion to intravenous medications. Entonox patients reported more pain (p < 0.0001), tolerated colonoscopy less well (p < 0.0001), were less satisfied (p = 0.01), and less willing to undergo colonoscopy again under the same circumstances (p = 0.04). Of patients receiving intravenous medication, 91% found colonoscopy less unpleasant and 9% as unpleasant as anticipated; this compares with 52% and 21% Entonox patients, respectively, and an additional 27% Entonox patients who found colonoscopy more unpleasant than anticipated. Recovery was faster among Entonox patients (median 30 versus 60 minutes, p < 0.0001). CONCLUSION: Entonox is less effective than midazolam with meperidine for colonoscopy but is acceptable in many patients and allows faster recovery.

Treatment of Helicobacter pylori infection to reduce gastric cancer incidence: uncertain benefits of a community based programme in Australia.

Helicobacter pylori is a cause of gastric adenocarcinoma, but the role of H. pylori eradication in reducing cancer risk is unknown. We sought to estimate the benefits of a screening and treatment programme for H. pylori infection, aimed at reducing the incidence of gastric cancer in Australia. The impact of this programme on cancer incidence was evaluated in sensitivity analyses utilizing Western Australian Cancer Registry data and published data on the epidemiology of H. pylori and gastric cancer. The impact of variation in parameters used in the sensitivity analyses was substantial, ranging from a 38% reduction in lifetime risk of gastric cancer in a best-case to 3% in a worst-case scenario. In an intermediate-case scenario there is a 23% reduction in lifetime risk, but in real terms this reflects a fall in cumulative incidence from 0.7 to 0.5% for males or 0.3 to 0.2% for females. The projected cumulative lifetime incidence of gastric cancer in H. pylori-infected males is 2.2% and 0.9% for females; this contrasts with 0.4 and 0.2%, respectively, for those never infected. According to an intermediate-case scenario, to prevent one gastric cancer, screening with or without subsequent treatment would be required in 617 men or 1639 women. Furthermore, this programme may be less effective in reducing cancer incidence than would be achieved naturally over the next 15 years, providing the current annual decline in gastric cancer incidence continues. In conclusion, the benefits of a community based programme of H. pylori eradication in terms of cancer risk reduction remain unclear, related largely to uncertainties in the parameters used to calculate these benefits. In Australia, any benefits obtained are likely to be, at best, modest.

Nodular regenerative hyperplasia of the liver: the importance of combined macroscopic and microscopic findings.

A 40-year-old man with rheumatoid arthritis, splenomegaly and mild thrombocytopenia presented with gross ascites and a history of excess alcohol consumption. Oesophageal varices were documented endoscopically. Alcoholic cirrhosis was suspected and laparoscopy revealed a macronodular liver surface. Liver biopsy disclosed subtle microscopic structural variations which together with the laparoscopic findings were consistent with the diagnosis of nodular regenerative hyperplasia. The importance in diagnosis of macroscopic appearance combined with histological findings is emphasised. Clinically significant portal hypertension may be present at a histologically early stage of this condition.

Nonattendance at outpatient endoscopy.

BACKGROUND AND STUDY AIMS: Nonattendance at outpatient endoscopy leads to inefficiency and delay in diagnosis. We aimed to identify factors associated with failure to attend outpatient gastroscopy and colonoscopy. PATIENTS AND METHODS: We carried out a retrospective audit of nonattendance at outpatient endoscopy over a 12-month period at our tertiary hospital endoscopy unit. Attending patients on the same endoscopy list were used as controls. Patient charts and referral letters were reviewed. The information collected included referral source, time between referral and procedure, indication and type of procedure, reason for nonattendance and history of previous endoscopy. Following the audit a trial of telephone reminders was implemented over a 3-month period. RESULTS: From 2157 outpatient procedures that were scheduled, 263 nonattendees (12.2 %) were identified with 261 controls. Of the nonattendees, 109 (41 %) did not attend for colonoscopy, 121 (46 %) did not attend for gastroscopy and 33 (13 %) failed to turn up for combined procedures. Monday was the most common day of the week for nonattendance (40 % of nonattenders). Nonattendees were younger (46 +/- 14 vs. 55 +/- 16, P < 0.001), less likely to be referred from a gastroenterologist ( P < 0.001) or private practice ( P = 0.02) and more likely to be referred from the emergency department ( P = 0.007). Subsequent to this, a 3-month period of telephone reminder reduced nonattendance rates from 12.2 % to 9 % ( P = 0.03). CONCLUSIONS: Younger patients scheduled for outpatient endoscopy on Mondays who are not referred by a gastroenterologist or private physician are more likely not to attend. These patients should be targeted for interventions designed to increase attendance. Telephone reminders have a modest effect on reducing nonattendance rates.