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Biomedical subjects

D A Waller

Publications and source records attributed to D A Waller.

At least 55 records · Page 3Linked to original sources
PubMed1995

Engineered oryzacystatin-I expressed in transgenic hairy roots confers resistance to Globodera pallida.

The cysteine proteinase inhibitor, oryzacystatin-I (Oc-I), and several engineered Oc-I variants have been tested for efficacy in inhibiting growth and development of both the free-living nematode, Caenorhabditis elegans, and the plant parasitic nematode Globodera pallida. To assist in the design of protein engineering experiments to improve the efficacy of Oc-I, an alignment of 28 cystatins and a molecular model of Oc-I were generated. Inhibitory activities (Ki) of wild-type and variant forms of Oc-I against both papain and the C. elegans cysteine proteinase, gcp-1, were measured. For one variant, in which residue Asp86 was deleted (Oc-I deltaD86), the Ki was reduced by 13- to 14-fold. LD50 studies to test the effect of Oc-I and Oc-I delta D86 against C. elegans showed the relative median potency of Oc-I delta D86 to be 0.76 that of wild-type Oc-I. When expressed in tomato hairy roots both Oc-I and Oc-I delta D86 had a detrimental effect on growth and development of G. pallida. This effect was significantly greater on Oc-I deltaD86-expressing roots leading to a reduction in size of G. pallida females to a level at which fecundity is profoundly affected.

Amino Acid Sequence↗
PubMed1995

Bilateral sequential lung transplantation for end stage septic lung disease.

BACKGROUND: Bilateral sequential lung transplantation (BSLT) has been widely adopted as an alternative to combined heart and lung transplantation for the management of end stage septic lung disease in many transplant centres. METHODS: A retrospective review was undertaken of the first 32 consecutive patients with septic lung disease to undergo BSLT at the Freeman Hospital. RESULTS: Between April 1988 and October 1994 32 patients underwent BSLT. Survival at 30 days was 85% and actuarial survival at one year was 70%. Improved pulmonary function was seen in all surviving patients. CONCLUSION: BSLT for septic lung disease offers comparable survival to heart-lung transplantation, with excellent functional results. Long term results may be superior because the disadvantages of transplanting the heart are avoided.

Adolescent↗
PubMed1995

Video-assisted thoracoscopic pleurectomy in the management of malignant pleural effusion.

STUDY OBJECTIVE: To evaluate the outcome of pleurectomy using video-assisted thoracic surgery (VATS) for pleurodesis in patients with malignant pleural effusion. DESIGN: Cohort prospective study. Follow-up of patients from referral for thoracoscopy to death. SETTING: Regional Cardiothoracic Surgical Centre. PATIENTS: Nineteen patients (median age 63 years, range 51 to 84 years) with malignant pleural effusion, secondary to mesothelioma in 13 and metastatic adenocarcinoma in 6. INTERVENTION: Video-assisted parietal pleurectomy. MEASUREMENTS AND RESULTS: Median operating time was 35 min (range 15 to 60 min). The median fall in hemoglobin concentration in the first 24 h postsurgery was 1.1 g/dL (0.3-2.5 g/dL). The median postoperative morphine requirement was 1.25 mg/h (0-6.2 mg/h) in the first 12 h postoperatively. All patients were successfully extubated in the operating room, without the need for reventilation, and all patients were successfully discharged from the hospital with a median postoperative stay of 5 days (range 2 to 20 days). At current median follow-up of 12 months (range 4 to 17 mon) 6 patients died of their underlying disease. In the remaining 13 patients, two have developed recurrent effusions. CONCLUSIONS: Using VATS to perform parietal pleurectomy is a safe, effective method of obtaining palliative pleurodesis in patients with malignant effusions.

Aged↗
PubMed1994

Videothoracoscopic operation for secondary spontaneous pneumothorax.

Thoracotomy for the management of a secondary spontaneous pneumothorax is associated with a high perioperative risk related to the presence of underlying lung disease. Videothoracoscopy offers the potential therapeutic benefits of a minimally invasive approach. We report on a series of 22 patients (19 men and 3 women) with a mean age of 70 years (range, 46 to 92 years) who underwent videothoracoscopic surgical procedures for the treatment of secondary spontaneous pneumothorax. All patients had emphysema; their mean preoperative forced expiratory volume in 1 second was 48% of predicted and their mean forced vital capacity was 64% of predicted. Eighteen patients presented with a persistent air leak and their mean preoperative hospital stay was 18 days (range, 6 to 40 days). Pleurectomy was performed in all 22 patients, together with bullectomy in 20 patients, with a mean overall operating time of 57 minutes (range, 24 to 90 minutes). General anesthesia was used in each patient. Single-lung ventilation, used in the majority, was found to be superior to high-frequency jet ventilation. The postoperative analgesic requirement was minimal (average, 15 mg of morphine in the first 12 hours), and no patient required reventilation. A revisional thoracotomy for the management of a persistent postoperative air leak was required in 4 patients, one of whom subsequently died in respiratory failure. The mean postoperative stay was 9 days (range, 3 to 26 days). At a mean follow-up of 8.6 months (range, 2 to 15 months), no pneumothorax had recurred.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Videothoracoscopic pleurectomy after contralateral single-lung transplantation.

Left single-lung transplantation in a 46-year-old man was complicated by spontaneous contralateral pneumothorax during the immediate postoperative period. This persisted despite chemical pleurodesis, but was successfully treated by videothoracoscopic pleurectomy, with minimal effect on respiratory function. The increasing use of single-lung transplantation for emphysema may increase the incidence of such problems from the native lung. Minimally invasive techniques may be of great clinical benefit in this situation.

Chest Tubes↗
PubMed1994

Video-assisted thoracoscopic surgery versus thoracotomy for spontaneous pneumothorax.

In a prospective comparison, 60 patients suffering from complicated spontaneous pneumothorax were randomly allocated to receive treatment by a video-assisted thoracoscopic surgery (VATS) technique or by thoracotomy. Thirty patients underwent bullectomy and apical pleurectomy by VATS performed through three 2-cm incisions (group V) and 30 patients underwent a similar surgical procedure through a posterolateral thoracotomy (group T). The median operating time was significantly longer in group V (45 versus 37.5 minutes; p < 0.05), but the postoperative analgesic requirement and hospital stay were less than those in group T. On the third postoperative day, the reductions in the forced expiratory volume in 1 second and forced vital capacity were significantly lower in group V than in group T (p < 0.05 and p < 0.01, respectively). Initial treatment of the spontaneous pneumothorax was effective in 27 patients (90%) in group V and in 29 patients (97%) in group T. There have been two late recurrences in group V and one in group T at a median follow-up of 15.1 months and 16.3 months, respectively. Within the study group, 30 consecutive patients presented with primary spontaneous pneumothorax. In this subgroup there was no significant difference in the operating time between VATS and thoracotomy, but postoperative pain, hospital stay, and pulmonary dysfunction were all less for those undergoing VATS. All treatment failures were in the subgroup of 30 consecutive patients who presented with secondary spontaneous pneumothorax, and the hospital stay in this group was prolonged by the use of VATS. We conclude from our findings that VATS is superior to thoracotomy in the treatment of primary spontaneous pneumothorax.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Carbon dioxide laser bronchoscopy--a review of its use in the treatment of malignant tracheobronchial tumours in 142 patients.

We report our experience over an 8-yr period, 1984-1991, of the use of the carbon dioxide (CO2) laser in the treatment of otherwise inoperable malignant tracheobronchial lesions. In that period 142 patients (84 male, 58 female; median age 63 years) underwent 278 procedures. The trachea was the site of treatment in 44 patients, the carina in nine, a main bronchus in 80 and a lobar bronchus in nine. All resections were performed under general anaesthesia via a rigid bronchoscope. Symptomatic relief was obtained in 103 of the 116 patients whose main complaint was dyspnoea. Overall there was a mean improvement in forced expiratory volume in 1 s (FEV1) of 27%, in peak expiratory flow (PEF) of 22% and in forced vital capacity (FVC) of 7%. Most improvement in FEV1 and PEF was obtained by the treatment of tracheal lesions. Three patients died within 24 h of surgery and 30 day mortality was 18%. At a mean follow-up of 18.3 months the mean post-laser survival is 5 months. While the CO2 laser has limitations in the treatment of distal tumours when compared to the neodymium/yttrium aluminium garnet (Nd:YAG) laser, there was no higher incidence of complications. We have found CO2 laser bronchoscopy to be an effective palliation of inoperable malignant tumours particularly of the trachea and main bronchi.

Adult↗
PubMed1994

Cognitive function in children who receive organ transplantation.

The number of children who undergo cardiac, renal, and liver transplantation continues to increase. This review of the literature describing their cognitive function indicates that deficits ranging from gross IQ delay to subtle neuropsychological dysfunction are present in some of these children both before and after transplantation. However, with the exception of certain definite contributors to vulnerability, such as cyanotic heart disease, early onset of disease, and growth deficits in infancy (particularly in head circumference and height), the correlates of cognitive deficits are not clear. Problems with determining contributing variables include significant heterogeneity within study populations, difficulties obtaining appropriate control groups, and the need for longitudinal, long-term studies. Additional research is required to address limitations of past studies.

Adolescent↗
PubMed1994

Video-assisted thoracoscopic placement of paravertebral catheters: a technique for postoperative analgesia for bilateral thoracoscopic surgery.

Paravertebral catheters were placed bilaterally through a Tuohy needle under direct video control in a patient undergoing video-assisted thoracoscopic (VAT) surgery for recurrent, bilateral pneumothoraces. Postoperative analgesia was produced by infusing bupivacaine through the catheters. This provided good analgesia. VAT placement of paravertebral catheters is easily accomplished and may be a part of the surgical procedure.

Adult↗
PubMed1994

Videothoracoscopy in the diagnosis of intrathoracic pathology: early experience.

We report our experience using the new technique of videothoracoscopy in the diagnosis of intrathoracic pathology. In the last 12 months, 40 patients (24 male; 16 female) have undergone investigation by this method. Lung biopsy has been performed in 17 patients, pleural biopsy in 20 patients and mediastinal biopsy in three patients. The majority had been referred after other investigations had been inconclusive. All biopsies were diagnostic except one mediastinal biopsy. This early experience suggests that videothoracoscopic biopsy is a well-tolerated technique with high diagnostic yield.

Adolescent↗
PubMed1993

Structure of chicken annexin V at 2.25-A resolution.

The crystal structure of chicken annexin V has been solved by molecular replacement and refined at 2.25 A. The final R factor is 19.7% with good geometry. The chicken annexin V structure is very similar to the human annexin V structure, with four similar domains each containing five helices. The structure includes three calcium ions in domains I, II, and IV, each bound by the characteristic K-G-X-G-T-(38 residues)-D/E motif. In view of the structural similarity between human and chicken annexin V, we suggest that they have a common vital function which developed early in evolutionary history.

Amino Acid Sequence↗
PubMed1993

Noncardiogenic pulmonary edema complicating lung resection.

Postresectional pulmonary edema is a rare but potentially fatal complication of thoracic operations. In a retrospective study of 402 lung resections we have identified 11 cases of postresectional, noncardiogenic pulmonary edema. We have analyzed the individual data to test recognized hypotheses regarding this condition. Pulmonary edema occurred in 5.1% of right pneumonectomies, 4.0% of left pneumonectomies, and 1% of all lobectomies. In 2 patients the symptoms occurred immediately after operation; in the other 9 the mean interval to diagnosis was 43.4 hours. All 11 patients were in a positive fluid balance in the first 24 hours after operation (mean, 20.8 +/- 9.1 mL/kg). However, there was no significant difference between this value and the respective values for control groups of 20 patients having pneumonectomies and 20 patients having lobectomies in whom pulmonary edema did not develop. Our findings differ from other reported series in that perioperative fluid overload was not found to be a significant contributory factor in the development of postresectional pulmonary edema. We discuss other possible mechanisms for this phenomenon.

Aged↗
PubMed1993

Tridimensional Personality Questionnaire and serotonin in bulimia nervosa.

To determine the relationship between Tridimensional Personality Questionnaire (TPQ) scales and bulimia nervosa, TPQ scores of 27 bulimic women, age range 21-59, were compared with values for an age-matched sample of 128 normal control women drawn from the national norming sample by Przybeck. Scores for Novelty Seeking and Harm Avoidance were significantly higher, while scores for Reward Dependence were significantly lower for the bulimic women. A stepwise regression model of severity of purging on TPQ selected Novelty Seeking and a composite depression score, with Novelty Seeking being the stronger of the two predictors. Whole blood serotonin levels did not relate to TPQ scores or to purging frequency.

Adult↗
PubMed1993

Iatrogenic vascular injury following arterial cannulation: the importance of early surgery.

Prospective data were collected over a 7-year period on patients undergoing repair of iatrogenic vascular injury following arterial cannulation. From 9375 procedures (7790 coronary angiograms, 835 coronary angioplasties, 445 other cardiac catheterizations, 155 femoral angiograms, 150 peripheral angioplasties) surgical repair was required in 26 patients. The overall incidence of significant injury was 0.28% and higher in therapeutic than diagnostic procedures. The mode of presentation included: critical limb ischaemia in 18 cases, false aneurysm in three, haematoma in three and claudication in two. The common femoral artery was the most common site of injury. No patient presenting with false aneurysm or haematoma suffered any deleterious sequelae. However, 50% of those presenting with critical ischaemia suffered permanent disability after operation. The median delay to surgery was significantly longer in this group (24 versus 4 h; P < 0.001) but there was no difference in age or incidence of underlying peripheral vascular disease. The physical, psychological and litigious sequelae of the complications of iatrogenic vascular injury cannot be overstated. It is strongly advocated that immediate surgical consultation be applied when limb ischaemia is suspected.

Adolescent↗
PubMed1993

Videothoracoscopy in the treatment of spontaneous pneumothorax: an initial experience.

We report an initial experience with the new and potentially advantageous technique of videothoracoscopy in the treatment of pneumothorax. A series of 18 consecutive patients (14 male, 4 female) presenting with spontaneous pneumothorax over a 4-month period underwent surgical treatment by this method. The indication for surgery was recurrent pneumothorax in nine patients and persistent air leak in the remainder (median duration 15 days, range 5-28 days). Stapled apical bullectomy with apical parietal pleurectomy was performed in 14 patients, bullectomy alone was performed in one patient and pleurectomy alone in three patients. Additional talc pleurodesis was carried out in three of these patients. Median duration of operation was 53.5 min (range 35-120 min). The median postoperative drainage was 300 ml in 24 h (range 50-580 ml). The median duration of intercostal drainage was 48 h (range 24-384 h) and of postoperative hospital stay 4 days (range 3-18 days). The mean postoperative analgesic requirement was 1.3 mg morphine/h. Three complications required reoperation. In two patients a large air leak persisted after operation; one proceeded to thoracotomy for suturing of the air leak and in the other this was accomplished by videothoracoscopy. A further patient re-presented at 2 weeks with recurrent pneumothorax which was treated at thoracotomy. At a median follow-up of 68.5 days (range 10-124 days) this is the only recurrence. These complications were caused by errors in surgical technique early in our series. This initial experience of videothoracoscopic pleurectomy suggests it is an effective, well-tolerated treatment of spontaneous pneumothorax.

Adolescent↗
PubMed1992

The frequency of uniparental disomy in Prader-Willi syndrome. Implications for molecular diagnosis.

BACKGROUND: Prader-Willi syndrome is a genetic disorder characterized by infantile hypotonia, obesity, hypogonadism, and mental retardation, but it is difficult to diagnose clinically in infants and young children. In about two thirds of patients, a cytogenetically visible deletion can be detected in the paternally derived chromosome 15 (15q11q13). Recently, patients with Prader-Willi syndrome have been described who do not have the cytogenetic deletion but instead have two copies of the 15q11q13 region that are inherited from the mother (with none inherited from the father). This unusual form of inheritance is known as maternal uniparental disomy. Using molecular genetic techniques, we sought to determine the frequency of uniparental disomy in Prader-Willi syndrome. METHODS: We performed molecular analyses using DNA markers within 15q11q13 and elsewhere on chromosome 15 in 30 patients with Prader-Willi syndrome who had no cytogenetically visible deletion. We also studied their parents. Three patients with Prader-Willi syndrome who had a cytogenetic deletion served as controls. RESULTS: In 18 of the 30 patients without a cytogenetic deletion (60 percent), we demonstrated the presence of maternal uniparental disomy for chromosome 15 and its association with advanced maternal age. In another eight patients (27 percent), we identified large molecular deletions. The remaining four patients (13 percent) had evidence of normal biparental inheritance for chromosome 15; three of these patients were the only ones in the study who had some atypical clinical features. CONCLUSIONS: In about 20 percent of all cases, Prader-Willi syndrome results from the inheritance of both copies of chromosome 15 from the mother (maternal uniparental disomy). With the combined use of cytogenetic and molecular techniques, the genetic basis of Prader-Willi syndrome can be identified in up to 95 percent of patients.

Adult↗
PubMed1992

A comparative trial of aztreonam versus gentamicin in the treatment of urinary tract infections.

A prospective, randomized trial was conducted to compare the efficacy of aztreonam, a monobactam antibiotic, and gentamicin in the treatment of serious urinary tract infections. Fifty-five patients with a suspected or confirmed infection were randomized, 28 received aztreonam and 27 received gentamicin. Both antibiotics had a high clinical response rate (aztreonam 92%, gentamicin 85%). However, the duration of treatment was significantly shorter (p = 0.037, Wilcoxon Rank Sum Test) when aztreonam was used. There were no cases of toxicity with either antibiotic but 5 patients who received gentamicin required dose alteration. Aztreonam is well tolerated and is no less effective than gentamicin in the treatment of urinary tract infections and has advantages in convenience of use and duration of treatment.

Adult↗