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Biomedical subjects

Helen McCarthy

Publications and source records attributed to Helen McCarthy.

8 recordsLinked to original sources

Total esophagogastric dissociation: 10 years' review.

PURPOSE: Neurologically impaired children run a 12% to 45% risk of recurrent gastroesophageal reflux (GER) after fundoplication. Elimination of the reflux by "rescue" total esophagogastric dissociation (TEGD) encouraged us to use it also as a "primary" form of antireflux surgery in this group of patients. METHODS: Twenty-six (14 male, 12 female) patients underwent TEGD between 1994 and 2004, of which 16 were primary and 10 were rescue procedures for failed fundoplication. RESULTS: There was no operative mortality and postoperative complications were limited to one subphrenic collection, one esophagojejunal dehiscence, and one small bowel hernia beneath the jejunal Roux loop. Gastrostomy feeding was usually established by 3 to 5 days and the mean hospital stay was 10.2 days (range, 6-18 days). At follow-up of 7 months to 11 years, there was no recurrence of GER. Four late deaths were unrelated to the surgery. The children's nutritional status improved with the mean weight standard deviation score showing a statistically significant increase from -2.63 preoperatively to -0.96 postoperatively (Wilcoxon's signed rank P value < or =.005). CONCLUSIONS: Total esophagogastric dissociation is a safe definitive solution for GER because it eliminates all risk of recurrent reflux. We therefore feel that TEGD can be used as a primary treatment of choice for severely neurologically impaired patients who are experiencing GER and are completely dependant on tube feeds.

Digestive System Surgical Procedures↗

Education. Class act.

Having a course accredited by a university can add to quality and credibility. A project manager with both university and clinical experience will prove useful. Choosing the right project team and academic partner is vital.

Accreditation↗

High expression of activation-induced cytidine deaminase (AID) and splice variants is a distinctive feature of poor-prognosis chronic lymphocytic leukemia.

In chronic lymphocytic leukemia (CLL), analysis of immunoglobulin heavy chain variable regions for somatic hypermutation identifies 2 prognostic subsets, mutated and unmutated. Investigators have postulated that unmutated and mutated CLL arises from malignant transformation of pre- and post-germinal center (GC) B cells, respectively. Alternatively, unmutated cases may arise from B cells stimulated by T-cell-independent antigens or from GC B cells with inactive somatic hypermutation. Activation-induced cytidine deaminase (AID), a protein essential for somatic hypermutation, is expressed by GC B cells in which this process occurs. We investigated AID mRNA expression in 20 CLL cases. In 8 cases we detected high expression of wild-type AID mRNA and 2 splice variants; in 12 cases and 5 normal peripheral blood B-cell samples we detected no expression using standard conditions. Of 8 CLL cases that highly expressed AID, 7 were unmutated, suggesting that this subset may arise from GC-experienced B cells with inactive somatic hypermutation, and may predict prognosis.

Alternative Splicing↗

Incidence of potential glycosylation sites in immunoglobulin variable regions distinguishes between subsets of Burkitt's lymphoma and mucosa-associated lymphoid tissue lymphoma.

Recently, a high incidence of novel N-glycosylation sites introduced by somatic mutation was observed in the immunoglobulin variable region genes of follicular lymphoma. As these are positively selected and are uncommon in normal B cells, they may have a role in tumour growth and behaviour. Sites are not characteristic of chronic lymphocytic leukaemia or myeloma, but are detectable in approximately 50% of diffuse large cell lymphomas. Another feature of the variable region genes of certain lymphomas is ongoing somatic mutation. To determine whether glycosylation is associated with this phenomenon, we analysed variable region gene sequences of Burkitt's lymphoma (BL) and mucosa-associated lymphoid tissue (MALT) lymphoma. Novel sites were common in endemic BL (82%) and in 4/5 patients with Iranian BL. However, sporadic BL had a lower incidence (43%). Patients with MALT lymphoma had a low frequency (9%) of novel sites, comparable to normal B cells. These findings distinguish glycosylation sites from ongoing mutation and may reflect different environmental influences on these tumours.

Binding Sites↗

Acquisition of potential N-glycosylation sites in the immunoglobulin variable region by somatic mutation is a distinctive feature of follicular lymphoma.

Most patients with follicular lymphoma (FL) have somatically mutated V genes with intraclonal variation, consistent with location in the germinal center site. Using our own and published sequences, we have investigated the frequency of potential N-glycosylation sites introduced into functional V(H) genes as a consequence of somatic mutation. FL cells were compared with normal memory B cells or plasma cells matched for similar levels of mutation. Strikingly, novel sites were detected in 55 of 70 (79%) patients with FL, compared to 7 of 75 (9%) in the normal B-cell population (P <.001). Diffuse large B-cell lymphoma (DLCL) showed an intermediate frequency (13 of 32 [41%] patients). Myeloma and the mutated subset of chronic lymphocytic leukemia showed frequencies similar to those of normal cells in 5 of 64 (8%) patients and 5 of 40 (13%) patients, respectively. In 3 of 3 random patients with FL, immunoglobulin was expressed as recombinant single-chain Fv in Pichia pastoris, and glycosylation was demonstrated. These findings indicate that N-glycosylation of the variable region may be common in FL and in a subset of DLCL. Most novel sites are located in the complementarity-determining regions. V(H) sequences of nonfunctional V(H) genes contained few sites, arguing for positive selection in FL. One possibility is that the added carbohydrate in the variable region contributes to interaction with elements in the germinal center environment. This common feature of FL may be critical for tumor behavior.

Amino Acid Sequence↗