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Biomedical subjects

D Wall

Publications and source records attributed to D Wall.

70 records · Page 4Linked to original sources
PubMed1988

A new method of segmental orthotopic liver transplantation in children.

Orthotopic liver transplantation requires matching of the donor and recipient for size. The rarity of suitable pediatric and infant donors in many countries has resulted in the acceptance of the principle of a reduced-sized adult liver graft for children. A new method of segmental orthotopic liver transplant is described. This method involves resecting the recipient liver off the inferior vena cava, which is left in situ, and the donor hepatic vein is anastomosed end to side to the inferior vena cava. The technique allows orthotopic liver transplantation with widely mismatched sizes from adults to infants.

Anastomosis, Surgical↗
PubMed1987

The Queensland Liver Transplant Programme: the first two years.

Orthotopic liver transplantation began in Brisbane in January 1985. During the first two years of the programme an assessment committee evaluated 55 patients (38 adults, 17 children). Patients were either accepted for transplantation, rejected as unsuitable or deferred for elective reassessment. All of the 10 adults who were rejected for transplantation because they had "too advanced" disease died within four months of assessment. Six children who were accepted for transplantation died before a suitable donor liver could be found. In the first two years, 21 orthotopic liver transplantations were performed on 18 patients (adults, 13 patients; children, five patients). Fifteen of 21 grafts were procured from within Queensland. Twelve (67%) patients are alive at three to 23 months and all have been discharged from hospital. Deaths in adults were due to sepsis (three patients), aspiration pneumonitis (one patient), rejection and hepatic artery thrombosis (one patient) and the recurrence of a hepatocellular carcinoma five months after discharge from hospital (one patient). Two patients underwent a second transplantation procedure because of chronic rejection at four months and at 11 months, respectively, after the initial operation. One patient received a second transplant for primary graft failure at four days after the operation. A scoring system which considered the presence of pre-operative patient factors, such as coma, ascites, malnutrition and previous abdominal surgery, partly predicted the operative blood loss and patient survival. In conclusion, orthotopic liver transplantation is being performed in Australia with survival rates that are comparable with those of established overseas units.

Adolescent↗
PubMed1987

Import of rat ornithine transcarbamylase precursor into mitochondria: two-step processing of the leader peptide.

The mitochondrial matrix enzyme ornithine transcarbamylase (OTC) is synthesized on cytoplasmic polyribosomes as a precursor (pOTC) with an NH2-terminal extension of 32 amino acids. We report here that rat pOTC synthesized in vitro is internalized and cleaved by isolated rat liver mitochondria in two, temporally separate steps. In the first step, which is dependent upon an intact mitochondrial membrane potential, pOTC is translocated into mitochondria and cleaved by a matrix protease to a product designated iOTC, intermediate in size between pOTC and mature OTC. This product is in a trypsin-protected mitochondrial location. The same intermediate-sized OTC is produced in vivo in frog oocytes injected with in vitro-synthesized pOTC. The proteolytic processing of pOTC to iOTC involves the removal of 24 amino acids from the NH2 terminus of the precursor and utilizes a cleavage site two residues away from a critical arginine residue at position 23. In a second cleavage step, also catalyzed by a matrix protease, iOTC is converted to mature OTC by removal of the remaining eight residues of leader sequence. To define the critical regions in the OTC leader peptide required for these events, we have synthesized OTC precursors with alterations in the leader. Substitution of either an acidic (aspartate) or a "helix-breaking" (glycine) amino acid residue for arginine 23 of the leader inhibits formation of both iOTC and OTC, without affecting translocation. These mutant precursors are cleaved at an otherwise cryptic cleavage site between residues 16 and 17 of the leader. Interestingly, this cleavage occurs at a site two residues away from an arginine at position 15. The data indicate that conversion of pOTC to mature OTC proceeds via the formation of a third discrete species: an intermediate-sized OTC. The data suggest further that, in the rat pOTC leader, the essential elements required for translocation differ from those necessary for correct cleavage to either iOTC or mature OTC.

Animals↗
PubMed1987

Stapled marlex mesh abdominal closure for repeat laparotomy in pancreatic disease.

A series of seven cases of severe pancreatic disease have been managed by repeat laparotomy for debridement of necrotizing pancreatitis, drainage of abscesses or control of haemorrhage with stapled marlex mesh closure of the abdominal wall. The use of a stapled marlex mesh at first laparotomy provides for safe, expedient relaparotomy until sepsis or haemorrhage is controlled.

Aged↗
PubMed1981

Fermentative conversion of cellulose to acetic Acid and cellulolytic enzyme production by a bacterial mixed culture obtained from sewage sludge.

A simple procedure that uses a cellulose-enriched culture started from sewage sludge was developed for producing cellulolytic enzymes and converting cellulose to acetic acid rather than CH(4) and CO(2). In this procedure, the culture which converts cellulose to CH(4) and CO(2) was mixed with a synthetic medium and cellulose and heated to 80 degrees C for 15 min before incubation. The end products formed were acetic acid, propionic acid, CO(2), and traces of ethanol and H(2). Supernatants from 6- to 10-day-old cultures contained 16 to 36 mM acetic acid. Cellulolytic enzymes in the supernatant were stable at 2 degrees C under aerobic conditions for up to 4 weeks and had the ability to hydrolyze carboxymethyl cellulose, a microcystalline cellulose, cellobiose, xylan, and filter paper to reducing sugars.

Journal Article↗
PubMed1975

Metastatic basal cell carcinoma.

A case of basal cell carcinoma which metastasized to an axillary lymph node is presented. There were no histological features that enabled either the presumed primary lesion or the metastasis to be distinguished from the usual non-metastasizing basal cell carcinoma. Evidence is presented that metastasis is considerably less freguent in Queensland that is reported in an overseas series.

Adult↗
PubMedDate not supplied

Red foxes (Vulpes vulpes) in Ireland as hosts for parasites of potential zoonotic and veterinary significance.

Intestinal washes, faecal flotations and serological examinations for antibodies to Toxoplasma gondii and Neospora caninum were used to assess the prevalence of parasites in carcases of foxes killed on roads or shot in the Dublin area and surrounding counties. The ascarids Uncinaria stenocephala and Toxocara canis were prevalent, as was the trematode Alaria alata. Taenia species, eggs of Capillaria species and sporocysts of Sarcocystis species were also found. Only one fox out of 70 examined was seropositive for N. caninum, whereas 24 of 51 were seropositive for T. gondii.

Ancylostomatoidea↗