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Biomedical subjects

N Wilson

Publications and source records attributed to N Wilson.

At least 19 recordsLinked to original sources
PubMed1992

Intron requirement for expression of the human purine nucleoside phosphorylase gene.

Abbreviated purine nucleoside phosphorylase (PNP) genes were engineered to determine the effect of introns on human PNP gene expression. PNP minigenes containing the first intron (complete or shortened from 2.9 kb down to 855 bp), the first two introns or all five PNP introns resulted in substantial human PNP isozyme expression after transient transfection of murine NIH 3T3 cells. Low level human PNP activity was observed after transfection with a PNP minigene containing the last three introns. An intronless PNP minigene construct containing the PNP cDNA fused to genomic flanking sequences resulted in undetectable human PNP activity. Heterogeneous, stable NIH 3T3 transfectants of intron-containing PNP minigenes (verified by Southern analysis), expressed high levels of PNP activity and contained appropriately processed 1.7 kb message visualized by northern analysis. Stable transfectants of the intronless PNP minigene (40-45 copies per haploid genome) contained no detectable human PNP isozyme or mRNA. Insertion of the 855 bp shortened intron 1 sequence in either orientation upstream or downstream of a chimeric PNP promoter-bacterial chloramphenicol acetyltransferase (CAT) gene resulted in a several-fold increase in CAT expression in comparison with the parental PNP-CAT construct. We conclude that human PNP gene expression at the mRNA and protein level is dependent on the presence of intronic sequences and that the level of PNP expression varies directly with the number of introns included. The disproportionately greatest effect of intron 1 can be explained by the presence of an enhancer-like element retained in the shortened 855 bp intron 1 sequence.

3T3 Cells↗
PubMed1992

Communicable disease in New Zealand.

Communicable diseases remain a major problem in New Zealand; one which often only comes to the attention of management when an outbreak occurs and health care dollars are required for disease control. Hepatitis B and rheumatic fever remain the two diseases that place New Zealand in the developing nation league. Overall, the impact on mortality is low (only 5% in the 1-14 year age group) as is the impact on potential years of life lost. Morbidity figures are not known with any degree of accuracy as they are dependent on a notification system acknowledged to be deficient and hospital discharge data which include only a fraction of cases for a few serious diseases. The main preventive action hinges on the childhood immunisation programme which has undergone recent change. The true impact of environmental hygiene measures, health promotion and education has not been evaluated.

Adolescent↗
PubMed1992

Cor triatriatum associated with total anomalous pulmonary venous drainage in the setting of mitral atresia and a restrictive interatrial communication.

A rare variant of cor triatriatum is described in which the proximal "accessory" chamber received all four pulmonary veins and drained into the levoatriocardinal vein and then into the innominate vein. The distal "true" chamber contained the left atrial appendage. The left atrioventricular valve was atretic and the interatrial septum was restrictive.

Angiography↗
PubMed1992

Balloon coarctation angioplasty in adolescents and adults: early and intermediate results.

Twenty-three adolescent and adult patients with native coarctation of the aorta underwent balloon dilatation. Dissection of the aorta developed in one patient. Data were collected on the remaining 22 patients. They ranged in age from 15 to 55 years (mean 23 +/- 9.2 years). Invasive measurement of the peak systolic gradient (PSG) and biplane angiography were performed before and immediately after angioplasty and at follow-up 4 to 48 months (mean 15 months) later. PSG before dilatation was 37 to 100 mm Hg (mean 66.9 +/- 19.9 mm Hg) and decreased to 0 to 30 mm Hg (mean 9.1 +/- 11 mm Hg) immediately after dilatation (p less than 0.001). Restenosis occurred in two patients 6 months after dilatation, and one patient had an incomplete dilatation. These three patients underwent successful redilatation and remained improved 12 to 19 months later. There was no significant change in gradient at repeat catheterization in the remaining 20 patients. PSG was 0 to 20 mm Hg (mean 5.8 +/- 7.2 mm Hg). Angiography showed that a small aneurysm developed in one patient immediately after dilatation and in another 6 months later. Eleven patients were restudied more than once, and no change in gradient or size of the aneurysm was noted at mean follow-up 25 months after dilatation. This study demonstrated that balloon angioplasty is an effective method of treating adolescent and adult patient with native coarctation of the aorta. However, because of the uncertain natural history of aneurysm after dilatation, this procedure should be considered investigational until much longer follow-up times are available.

Adolescent↗
PubMed1992

Successful transcatheter closure of patent arterial duct six years after balloon dilatation of coarctation of the aorta.

A boy underwent total transcatheter occlusion of a patent arterial duct six years after successful balloon angioplasty of a native coarctation of the aorta. After successful implantation of a 12 mm device in the patent arterial duct there was no gradient across the descending aorta and five hours later there was no residual leak across the occluded patent arterial duct as judged by color Doppler.

Angioplasty, Balloon, Coronary↗
PubMed1992

Radioimmunoassay measurement of albumin in urine is a valid method for monitoring analbuminemia in rats.

Plasma and urinary albumin levels, urinary creatinine and urine volumes were measured at two-week intervals in Nagase analbuminemic rats (NAR) of either sex at ages from 42 to 154 days. Age matched Sprague Dawley (SD) rats were used as controls. Plasma concentrations of immunoreactive albumin (iALB) in NAR ranged from 0.007 +/- 0.002 to 0.023 +/- 0.003 mg/ml, and were lower in younger rats. In SD rats, plasma iALB concentrations ranged from 18.9 +/- 1.0 to 46.2 +/- 6.4 mg/ml. Urinary iALB output in NAR was less than 0.05 micrograms/mg creatinine measured over a 24 hr period, whereas it was greater than 20 micrograms/mg creatinine in the SD rats. Measurement of urine iALB concentrations in the NAR colony appears to be a reliable and a non-invasive method for monitoring the persistence of hypoalbuminemia.

Age Factors↗
PubMed1992

Ectoparasitic mites (Acari) of sympatric Brazilian free-tailed bats and big brown bats in Alabama.

Seven species of mites were recovered from 133 Brazilian free-tailed bats, Tadarida brasiliensis, and 94 big brown bats, Eptesicus fuscus, from February through November 1990 in colonies that shared roosting space in east-central Alabama. The macronyssid Chiroptonyssus robustipes (Ewing) was the most common mite on T. brasiliensis (964 mites, 87% of bats infested) and on E. fuscus (109 mites, 29% of bats infested). However, C. rubustipes normally is a specific parasite of T. brasiliensis. The macronyssids Steatonyssus ceratognathus (Ewing) and S. occidentalis (Ewing) were recovered from both species of bats in low numbers. S. ceratognathus is not a typical parasite of either species of bat, but S. occidentalis normally is specific to E. fuscus. Predictably, S. occidentalis was most frequently collected from E. fuscus (16 mites, 9% of bats infested), but two specimens were recovered from T. brasiliensis. Five specimens of the laelapid Androlaelaps casalis (Berlese) (a mite that is frequently associated with rodents) and one specimen of the myobiid mite Ewingana (Doreyana) longa (Ewing) (a specific ectoparasite of T. brasiliensis) were also recovered from T. brasiliensis. Singletons of the rosensteiniids Mydopholeus sp. and Nycteriglyphites pennsylvanicus Fain, Lukoschus & Whitaker were the only additional mites collected from E. fuscus; both of these mites have previously been collected from bats or their guano but are recorded here from Alabama for the first time. With respect to ectoparasite cross-infestations, E. fuscus appears to be at greater risk from sharing roots with T. brasiliensis. This is highlighted by the comparatively large numbers of C. robustipes that occurred on E. fuscus and the low numbers of S. occidentalis on T. brasiliensis. Although mites were the only arthropods recovered from bats in this study, a separate survey in 1991 revealed that the bat bug Cimex adjunctus Barber infested some other colonies of T. brasiliensis and E. fuscus in Alabama.

Alabama↗
PubMed1992

Transoesophageal echocardiography in neonates, infants and children: applicability and diagnostic value in everyday practice of a cardiothoracic unit.

OBJECTIVE: To determine the applicability of and information obtained by transoesophageal echocardiography in neonates, infants, and children in every day practice of a cardiothoracic unit. DESIGN: Four month prospective study. SETTING: Supraregional centre for paediatric cardiothoracic services. PATIENTS AND METHODS: 58 patients aged between four days and 16 years with a wide range of cardiovascular disease underwent transoesophageal echocardiography under sedation or general anaesthetic. One of two paediatric probes (6 or 7 mm diameter), or an adult probe (13 mm in diameter) was used. Whenever possible the investigation was immediately preceded by precordial echocardiography. MAIN OUTCOME MEASURES: Success, failure, technical difficulties, and complications of probe introduction and, when possible, comparison of the information obtained with that obtained from precordial echocardiography. RESULTS: Introduction of the probe was successful in 57 of the 58 patients. The only complication encountered was transient bradycardia during manipulation of the probe in a 2.2 kg baby. The adult (13 mm) probe was successfully used in children as small as 7.0 kg. Below this weight a smaller paediatric probe was required. In 56% of cases transoesophageal ultrasound provided information not obtained from the precordial approach. The technique was of particular value perioperatively and in the immediate postoperative period in neonates and infants and in the presence of valve prostheses and the investigation of mediastinal tumours in older children. CONCLUSIONS: Transoesophageal echocardiography is a valuable additional investigative tool for children of all ages. It is of particular value when acquisition of precordial image is impaired around the time of and after operation and in children with prosthetic valves or mediastinal tumour. Image quality was superior with the adult probe and we recommend the use of this probe unless the patient's weight is below 7 kg, when a paediatric probe allows this technique to be used usefully and safely in babies as small as 2.2 kg.

Adolescent↗
PubMed1992

Successful repair of pulmonary atresia with ventricular septal defect without the use of a conduit: a new surgical option. Report of two cases.

A new technique for the restoration of continuity between the pulmonary artery and the right ventricle in pulmonary atresia with ventricular septal defect without the use of a conduit is described. This was accomplished by anastomosing the inferior margin of the distal pulmonary artery to the apex of a T-shaped infundibular ventriculotomy to form the posterior wall of the reconstructed right ventricular outflow tract. A winged patch of bovine pericardium was then used for the anterior wall to complete reconstruction of the transannular right ventricular outflow tract. This technique was used successfully in two patients.

Anastomosis, Surgical↗
PubMed1992

99mTechnetium-labelled red blood cell scintigraphy as an alternative to angiography in the investigation of gastrointestinal bleeding: clinical experience in a district general hospital.

99mTechnetium-labelled red blood cell scintigraphy (99mTc RBC scintigraphy) was used as the second-line investigation to localise bleeding in 23 patients (11 male, 12 female; mean age 67 years) presenting with active bleeding per rectum. Scintigraphy was available on a 24 h basis. A total of 18 patients had positive scans (78%). Surgery was performed urgently in 11 patients and the site of bleeding, as predicted by scintigraphy, was confirmed in 9 (82%). 99mTc RBC scintigraphy was less useful in patients who were not bleeding actively or who were being investigated for chronic anaemia. This study suggests that 99mTc RBC scintigraphy can play a useful role in the preoperative localisation of unexplained gastrointestinal bleeding in hospitals with nuclear medicine facilities, but confirms it has little place in the management of patients unless they are bleeding actively.

Adult↗
PubMed1991

Risk factors for hepatitis B at a residential institution for intellectually handicapped persons.

We conducted a cross sectional study to evaluate risk factors for hepatitis B (HBV) infection among residents and staff at Braemar Hospital in Nelson. We obtained serum and abstracted medical charts for 114 of the 122 (93%) residents; 129 of 226 (57%) staff members completed questionnaires and provided serum. Seventy (61%) of the residents had serological markers of past HBV infection, including 42 (37%) who were identified as carriers. Residents' risk of being infected increased by 17% for each additional year they had lived in this institution; there were no significant differences in the likelihood of having markers of HBV infection by a person's age at first admission, sex, ethnicity, admission diagnosis, medical history, or various behavioural attributes. Among staff, 20 (16%) showed evidence of past exposure to HBV, but none were identified as being carriers; of these, 5 (25%) reported having received hepatitis B vaccine. Excluding the vaccinated persons who were seropositive, there were no demographic or occupational risk factors that were significantly associated with having serological markers of past HBV exposure. To control further HBV transmission in this setting, all current and future residents, as well as staff members who have direct contact with residents, should be screened for serological markers of HBV and persons identified as being susceptible should be vaccinated.

Adult↗
PubMed1991

Long-term outcome for children with acute renal failure following cardiac surgery.

Acute renal failure requiring dialysis occurred in 34 children (2.9%) following cardiac surgery over a five year period. 17 children (50%) recovered renal function with 11 (32%) long-term survivors. The long-term outcome for the survivors, in terms of renal function, was studied from 1 to 5 years after their episodes of acute renal failure. Three children had significant abnormalities of renal function despite normal urinalysis. Detailed assessment of renal function is advocated for children who survive acute renal failure following cardiac surgery.

Acute Kidney Injury↗