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Biomedical subjects

L Delbridge

Publications and source records attributed to L Delbridge.

At least 73 records · Page 4Linked to original sources
PubMed1991

Prognostic significance of nuclear DNA content in phaeochromocytoma.

Nuclear DNA content of 27 phaeochromocytomas was measured by image analysis of thin sections and monolayer smears of nuclei extracted from thick sections (cytospins) using archival paraffin-embedded tissue blocks. Recurrence was assessed on the basis of clinical follow-up or urinary catecholamine levels. The mean follow-up was 5.0 years, with a range of 4 months to 15 years. Although it is not possible to differentiate accurately malignant tumours using DNA analysis, prediction of benign tumours is possible. Using thin sections, all tumours were benign when the percentage of cells with a DNA content of 2.5 c (2 c = diploid) was less than 40% and the DNA content of 5 c was less than 4%. Using the cytospin preparation, all diploid tumours were benign. Thus, patients with diploid tumours may be saved intensive long-term follow-up. Aneuploid and tetraploid tumours, however, continue to require careful lifelong follow-up.

Adolescent↗
PubMed1991

Comparison of image analysis and flow cytometric determination of cellular DNA content.

A good correlation (r = 0.94) was obtained between the DNA indices (DI) using flow cytometry and image analysis of nuclei cytospins extracted from paraffin wax embedded tumour sections. Some of the limitations and problems associated with image analysis which came to light included an unacceptably high coefficient of variation (CV) and a "left-shift" in the DI in most DNA histograms obtained when using image analysis of 5 microns sections. In contrast, the DNA histograms generated using image analysis of cytospun nuclei from paraffin wax blocks were of good quality and similar to those obtained using flow cytometry. Variability in Feulgen staining was common and an important source of error despite rigorous control of the staining technique. This could be overcome by using internal controls such as fibroblasts rather than external controls (rat hepatocytes) to determine the diploid DI with image analysis. A thorough understanding and appreciation of the methodological problems associated with image analysis and flow cytometric determination of DNA content is required before these methods find widespread clinical application.

Adrenal Gland Neoplasms↗
PubMed1991

Use of X-ray diffraction in study of human diabetic and aging collagen.

Extensive investigations of the solubility and fluorescence of collagen fibers in diabetes have revealed that there are significant changes in their physical properties. These changes are associated with increased cross-link formation. We used X-ray diffraction to study these changes in human extensor tendons at a molecular level in relation to both aging and diabetes. Our results indicate that diabetes induces significant alterations in the ultrastructure of collagen in the lateral packing of the molecules and the axial structure of the specimen. These changes can be induced in normal tendon by incubation in ribose and glucose-6-phosphate but are different from those associated with the normal process of aging.

Adolescent↗
PubMed1991

Transhepatic portal vein catheterization for localization of insulinomas: a ten-year experience.

One of the most important factors in the management of insulinomas is the ability to localize the tumor accurately either before or during surgery. We prospectively carried out transhepatic portal venous sampling (THPVS) for tumor localization in 35 of 40 patients with organic hyperinsulinism during a 10-year period. In 32 patients who underwent THPVS and in whom a single tumor was subsequently identified surgically, the maximal insulin gradient was located in the vicinity of the tumor in 100% of cases. Specific regionalization of the tumor on the basis of the site of the maximal insulin gradient to one of three regions (the tail, the body/neck region, and the head/uncinate region) gave a sensitivity of 81% and a specificity of 91%. In contrast, the use of specific cutoff levels for the insulin gradient as a guide to the presence of a tumor in one of these three regions did not increase the accuracy, leading instead to a significant loss of sensitivity with no comparable increase in specificity. There were no major complications from the procedure in any patient. The initial use of computed tomographic/ultrasound scanning and selective angiography localized only 46% of tumors, whereas subsequent THPVS led to the accurate preoperative localization of 100% of all tumors submitted to surgery. Although the surgeon would have identified 81% of the tumors correctly at operation, in 19% (n = 6) he would have failed. Four tumors were in the uncinate and two were in the head. It seems that in patients with proved or established organic hyperinsulinism, THPVS may continue to be of value, if only to regionalize the tumor, especially those in the pancreatic head and uncinate process so as to preclude noncurative operations on the body and tail of the pancreas.

Adult↗
PubMed1990

Fine needle biopsy of thyroid nodules: the importance of technique.

Fine needle biopsy (FNB) is the most accurate method available for the investigation of single thyroid nodules. The exact technique employed, however, varies considerably among clinicians: in our institution the incidence of 'inadequate' specimens produced ranges from only 13 to 62%, depending on the individual performing the biopsy. In a prospective in vivo study, a variety of biopsy techniques employing different gauge needles and differing numbers of passes with and without aspiration were assessed with respect to the quality of cytological specimen produced. Criteria assessed included the number of cells or sheets of cells, cell clumping, blood contamination, amount of colloid, and overall slide quality. Samples obtained with a 21 gauge needle without aspiration consistently gave best individual cell morphology. On the other hand, samples obtained with a 23 gauge needle with five aspirated passes through the nodule gave the highest yield of cells with an acceptable minimal increase in the degree of blood contamination and cell clumping. In order to achieve consistent yields from FNB of thyroid nodules, a combination of these two techniques is recommended.

Adult↗
PubMed1990

Radical treatment of mal perforans in diabetic patients with arterial insufficiency.

Forty patients with diabetes mellitus and severe mal perforans underwent dorsal excision of the involved metatarsal head with primary closure of the plantar ulcer. Patients were screened before operation with noninvasive studies documenting pulse examination, ankle pressure index, and toe blood pressures. Fifteen of 40 patients (38%) had no palpable pedal pulses. Three patients had vascular reconstruction before metatarsal head resection. Mean toe pressure of the entire group was 135 +/- 35 mm Hg (range, 60 to 190), with six patients having a pressure less than 100 mm Hg. All patients had primary healing of the plantar wound and secondary healing of the dorsal incision with no amputations or readmissions for forefoot sepsis in the mean follow-up of 38.5 months (range, 2 to 54 months). In seven patients with recurrent ulcers, no relationship was found between measured indexes of forefoot perfusion and recurrence. However, all patients with recurrence were noncompliant in returning for follow-up orthotic care. This technique provides a means to ensure rapid healing of severe mal perforans while decreasing hospitalization, wound care, and periods of immobilization and is applicable in diabetic patients with arterial insufficiency and toe pressure of at least 60 mm Hg.

Blood Pressure↗
PubMed1989

Increase in crosslinking of nonenzymatically glycosylated collagen induced by products of lipid peroxidation.

The increase in crosslinking in normal and nonenzymatically glycosylated rat tail tendon collagen after treatment with decomposing lipid hydroperoxides was assessed by measuring the breaking time of tendons immersed in 7 M urea under a 3 g weight at 40 degrees C (thermal rupture time). The incubation of tendons in 200 mM glucose for 43 h at 40 degrees C increased thermal rupture times from 5.15 to 26.38 min, (P less than 0.001) with no significant corresponding increase in tendons incubated in buffer alone. After incubation of the glycosylated tendons in the presence of peroxidized linoleic/arachidonic acid vesicles for about 20 h, their thermal rupture time increased to 3360 min (P less than 0.001). The rupture time for normal tendons after the same treatment was 206 min. These apparent crosslinking increases cannot be fully accounted for by reactions involving malondialdehyde, as incubation of both glycosylated and normal tendons in enzymatically produced malondialdehyde resulted in a modest two- to threefold increase in thermal rupture time.

Animals↗
PubMed1989

Trainee surgery in teaching hospitals: is there a cost?

The morbidity rate for 2858 patients undergoing thyroidectomy over the 10 year period January 1977-December 1986 was examined and related to the involvement of a surgical trainee in the operative procedure. There was no overall difference in specific complication rates related to the surgical procedure, being 13.8% when the procedure was undertaken by a consultant, and 13.1% when a surgical trainee was involved in the procedure. There was a significant increase (P = 0.0025) in operative time increasing from 127 min for the consultant to 146 min when the trainee was involved (a 15% increase). There was no significant difference in bed stay for any of the groups. Surgical trainees can be safely taught operative skills under supervision without risk of increased complications. There is a cost, however, to the hospital system in terms of increased demands on time and operative facilities.

Costs and Cost Analysis↗
PubMed1988

Catalysis of lipid peroxidation by glucose and glycosylated collagen.

Peroxidation of membranes of linoleic/arachadonic acid vesicles at 40 degrees C was catalysed by glucose or glycosylated collagen. Kinetics of hydroperoxide production were similar in both cases. There was a kinetic lag, the duration of which was inversely proportional to the amount of glucose or glycosylated collagen used to initiate the peroxidation. This was followed by a rapid increase in the rate of oxidation. The final rate was independent of the amount of catalyst added. Vesicle lysis accompanied the increases in peroxidation. Addition of desferrioxamine, an iron chelator, only partially inhibited the oxidative process.

Animals↗
PubMed1987

Total thyroidectomy. The preferred option for multinodular goiter.

Total thyroidectomy is an operation that has generally been reserved for the management of differentiated thyroid carcinoma. Over the last decade total thyroidectomy has become used increasingly and is now the preferred option in the authors' unit for the management of multinodular goiter affecting the entire gland. Over the period from 1975 to 1985, 853 thyroidectomies have been performed for multinodular goiter; of these, 115 have been total thyroidectomies. During that time, the incidence of total thyroidectomy for multinodular goiter has increased in percentage terms from 9% in 1975 to 50% in 1985. There have been two cases of permanent hypoparathyroidism and one case of permanent recurrent laryngeal nerve injury, and these occurred in patients who had less than total thyroidectomy. Total thyroidectomy is an appropriate operation for the management of diffuse multinodular goiter where the entire gland is involved because it precludes patients from requiring further surgery for recurrent disease, with its high associated risks. It must be emphasized, however, that protection of the recurrent laryngeal nerve and parathyroid glands must still be paramount in dealing with benign thyroid disease.

Goiter, Nodular↗
PubMed1987

Surgery for adrenal tumours: is operation for the small incidental tumour appropriate?

The last 15 years have seen a change in the indications for adrenalectomy. On the one hand there has been a decline in the number of operations for metastatic breast cancer due principally to the introduction of effective medical therapy. Moreover, the introduction of trans-sphenoidal techniques has reduced the number of adrenalectomies for Cushing's Disease. In contrast the introduction of CT scanning has seen an increase in the diagnosis of incidental adrenal masses, most of which turn out to be benign non-functioning adrenal cortical adenomas. During the period 1970-86, 124 adrenalectomies were performed at Royal North Shore Hospital. From 1970 to 1976 the primary indication for adrenalectomy was metastatic breast carcinoma (84%). Over the past three years one of the primary indications has been the discovery of an asymptomatic, non-functional adrenal mass on CT scan (26%) and, of these tumours, 95% have been less than 5 cm in size. Yet no incidentally discovered adrenal mass was an adrenocortical carcinoma and no adrenocortical carcinoma was smaller than 7 cm in diameter. We recommend that an asymptomatic adrenal mass less than 6 cm in size, with no evidence of function, should be managed conservatively.

Adenoma↗
PubMed1987

Rectal prolapse: relationship with joint mobility.

Joint mobility was assessed in 25 patients who had undergone surgery for complete rectal prolapse and in 25 age- and sex-matched control subjects. A significant increase in extensibility of the fifth finger was found in the patients with rectal prolapse. It was further found that there was a progressive decrease in joint mobility with age in both groups. The pathophysiology of rectal prolapse is complex. Factors considered to be important include rectal intussusception associated with the commonly observed lack of rectal fixation within the sacral hollow, with a deep Pouch of Douglas and weak pelvic floor musculature. The joint hypermobility demonstrated in these patients suggests an underlying connective tissue abnormality which perhaps contributes to the lack of rectal fixation within the pelvis and to the rectal wall intussusception.

Adolescent↗
PubMed1987

Hydatid disease at Royal North Shore Hospital: results of surgical treatment.

A study of the results of surgery for hydatid disease was undertaken at Royal North Shore Hospital for the period 1966-83. There were 51 patients who underwent surgery for this disease and follow-up was obtained in all but eight cases. Comparison of cumulative survivals for this group with that of a matched Australian population showed that patients undergoing surgical treatment of their hydatid can anticipate a normal life expectancy. There was no evidence that patients with extrahepatic disease fared any worse than those with disease confined to the liver. Documented recurrence of hydatid disease occurred in eight cases following surgery and only one patient actually died from hydatid disease. This was a case in which spillage occurred at the initial procedure. This paper is presented as a reminder that hydatid disease still occurs with sufficient frequency to pose therapeutic problems for surgeons. Whilst total eradication of the parasite will only occur with enforcement of public health measures, surgery would still appear to be effective therapy for established hydatid disease so long as care is taken to avoid cyst rupture.

Adolescent↗
PubMed1987

Effects of experimental diabetes, uremia, and malnutrition on wound healing.

The strength of linear wounds was studied in normal and diabetic rats in the first 8 wk after wounding. The strength of wounds from diabetic animals was found to be reduced compared with normal controls but could be improved by insulin treatment, especially when excellent metabolic control was achieved. There appeared to be both quantitative and qualitative defects in the formation of wound tissues in diabetic animals, because wound strength was not normalized when the thinner skin of diabetic animals was taken into consideration. This was different from the findings in rats with renal failure or malnutrition: in these two conditions, wound strength appeared reduced but was normalized when adjusted for skin thickness. Increased activity of aldose reductase did not appear to be an important factor in the impairment of wound healing in diabetes, because wound strength was not corrected by treatment with sorbinil, an aldose reductase inhibitor. The precise mechanism of abnormal wound strength in diabetes remains to be studied further, but careful control of diabetes, maintenance of nutrition, and treatment of systemic illness are important factors in the promotion of wound healing.

Animals↗
PubMed1987

Thyroid surgery in the elderly.

Thyroid disease is common in the elderly but appropriate surgical procedures are frequently avoided in the belief that the patient's age precludes a successful outcome. This avoidance may result in surgery having to be performed at a later stage as an emergency when conditions are not necessarily ideal for treatment of airway obstruction by goitrous tissue. Between 1970 and 1985, 575 patients aged over sixty years underwent thyroidectomy in The University of Sydney Department of Surgery at Royal North Shore Hospital. The most commonly performed procedure was total thyroid lobectomy (185); there were however a significant number of total thyroidectomies (86), 41% for benign and 59% for malignant thyroid pathology. The complication rate was considered to be acceptably low in this group. Complications of thyroid surgery itself occurred in 1.2%, recurrent laryngeal nerve palsy 1%, and hypoparathyroidism 0.2%. Other complications (4.8%) were those to be expected in an elderly patient population with multiple pathology and comprised myocardial infarction, cardiac arrhythmias and respiratory problems. There were 2 deaths in this group (0.4%), one occurred when the endotracheal tube perforated the trachea of a patient whose thyroid malignancy proved to be invading the trachea. The accumulated data in this study showed that age, regardless of pathological classification, was the major single prognostic factor for survival in thyroid malignancy. Aged patients can undergo thyroid surgery with no significantly added risk provided specific associated problems are addressed before operation.

Aged↗
PubMed1986

The impact of fine-needle aspiration biopsy on surgery for single thyroid nodules.

Biopsy by fine-needle aspiration has emerged as the most effective single technique for the investigation of single thyroid nodules. A comparison was made of patients who underwent surgery for single nodules in 1979 (before the introduction of fine-needle aspiration biopsy to this Department) and in 1984, after this technique had become fully established. Biopsy by fine-needle aspiration proved to be reliable in the selection of patients for surgery. The incidence of malignancy in each category was: malignant, 83%; atypical, 26%; inadequate, 7%; and benign, none. This contrasted with nuclear scanning and ultrasound techniques that were in use over that period, where the malignancy rate of nodules that showed no uptake of radioisotope was 11% and that of an ultrasound scan that demonstrated a "solid" or "cystic/solid" was 16%. Similarly, nodules that showed an uptake of radioisotope or an ultrasound scan that demonstrated a "cystic" image did not exclude malignancy reliably. As a result of fine-needle aspiration biopsy, there was a 60% reduction in the number of thyroidectomies for single nodules during its use with a higher yield, but no change in the absolute number, of patients with malignancy of the thyroid gland.

Adult↗