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Biomedical subjects

B Robinson

Publications and source records attributed to B Robinson.

At least 73 records · Page 4Linked to original sources
PubMed1996

Recurrent substernal nodular goiter: incidence and management.

BACKGROUND: Surgery for recurrent multinodular goiter is associated with an increased risk of complications. When recurrence occurs in a substernal location, difficulties associated with surgical removal may be even more significant. METHODS: Information relating to indications for surgery, procedure performed, pathologic findings, and surgical complications was obtained from a prospective thyroid surgery database maintained in our unit for the past 39 years. RESULTS: During the study period 234 patients underwent operation for retrosternal recurrence of a nodular goiter. In the majority of cases (51%) the indication for surgery was the presence of compressive symptoms. In only four cases was a sternal split required to remove substernal recurrence. Complications occurred in 35 patients, including four permanent recurrent laryngeal nerve palsies. No patient had permanent hypoparathyroidism. CONCLUSIONS: Surgery for recurrent substernal goiter, although technically demanding, can be performed with a minimum of morbidity if appropriate attention is paid to anatomy and embryology. A sternal split is only rarely required.

Adult↗
PubMed1996

C-myc oncogene expression in human melanoma and its relationship with tumour antigenicity.

Melanoma produces specific tumour antigens which are capable of eliciting an immune response. However, this tumour evades the immune system, in part, by downregulation of class I HLA antigens on the cell surface, which are required for T cell recognition. It has been suggested that the oncogene c-myc may have a role in effecting this change in vitro, however, the relationship between oncoprotein level and tumour antigenicity has not been established in human tumours. This study measured c-myc oncoprotein in 94 melanoma specimens (46 primary tumours and 48 regional metastases) using flow cytometry and evaluated class I HLA expression with immunohistochemistry. C-myc expression was found in 91 tumours (96%) with higher expression in metastases than primary melanomas (P<0.005). Class I HLA expression was found to show great variation although metastases showed less antigenicity than primary tumours (P<0.01). Analysis of the relationship between these two parameters revealed a highly significant correlation in both primary (P<0.01) and metastatic disease (P<0.01), with high oncoprotein being associated with down regulation of cell surface antigens. Knowledge of the control of tumour antigenicity is likely to provide an objective platform for the development of new strategies for immunotherapy.

Antigens, Neoplasm↗
PubMed1996

Primary hyperparathyroidism in childhood and adolescence.

OBJECTIVE: The aim of this study was to determine the nature of the presentation and pathology of primary hyperparathyroidism in children and adolescents and to compare these findings with adults. METHODOLOGY: Data were obtained from the Thyroid Surgery Database at Royal North Shore Hospital on all children and adolescents undergoing parathyroid surgery. These results were then compared to data obtained from the last 100 consecutive adult parathyroidectomies. RESULTS: A total of eight younger patients underwent parathyroidectomy including three children (0-12 years) and five adolescents (13-18 years). A common presentation in the younger age group was hypercalcaemic crisis (50%) with a serum calcium > 3.5 mmol/L and clinical signs of calcium intoxication. This compared to the adult age group where only 8% presented with crisis (P < 0.05). Eighty-eight per cent of the younger patients complained of abdominal symptoms compared to only 1% of adults. Seven of eight young patients had sporadic hyperparathyroidism. CONCLUSIONS: Primary hyperparathyroidism, although uncommon in the younger age group, is still most commonly associated with sporadic tumours. Familial syndromes do not constitute a large percentage of patients. Younger patients are more prone to present late with abdominal symptoms, toxicity and hypercalcaemic crisis, presumably due to delayed diagnosis of an uncommon condition in this age group.

Adenoma↗
PubMed1996

The aetiology, investigation and management of surgical disorders of the thyroid gland.

There have been many recent advances in our understanding of thyroid disease, including thyroid physiology, the molecular biology of thyroid neoplasms, guidelines for the management of surgical thyroid disease and the operative approach to thyroidectomy. The control of thyroid growth and function is better understood now that the thyroid stimulating hormone (TSH) receptor has been characterized as a G-protein coupled transmembrane receptor. The peripheral action of thyroid hormones is also better understood in terms of their interaction with nuclear thyroid hormone receptors. An adenoma-carcinoma sequence for the development of thyroid neoplasms has been proposed based on the characterization of a number of proto-oncogenes and tumour suppressor genes, and different pathways for the development of papillary and follicular thyroid carcinoma have been demonstrated. Fine needle biopsy has become, over the past few years, the principal diagnostic technique for evaluation of thyroid nodules, and has resulted in a significant reduction in the need for surgery for benign thyroid nodules. The approach to the management of thyroid carcinoma can now be based on comprehensive scoring systems for assigning patients to a particular risk group, the most recent of which is the MACIS system based on distant metastases (M), age (A), completeness of resection (C), invasion (I) and size (S). The capsular technique of thyroidectomy as described has now been shown to be the best method to preserve parathyroid blood supply, protect the recurrent laryngeal nerve and minimize the complications of thyroid surgery.

Drosophila Proteins↗
PubMed1996

A survey study of neuropsychiatric complaints in patients with Graves' disease.

One hundred thirty-seven patients with treated Graves' disease completed a questionnaire pertaining to neuropsychiatric complaints. Psychiatric symptoms, especially anxiety and irritability, were common prior to treatment of hyperthyroidism. These complaints appeared to result in delays in seeking treatment as well as delays in receiving appropriate diagnosis. Subjects reported significantly worse memory, attention, planning, and productivity while hyperthyroid than prior to becoming hyperthyroid, and, although somewhat improved once euthyroid, they reported residual cognitive deficits. These results suggest that neuropsychiatric impairments are highly prevalent in Graves' disease, may lead to initial misdiagnosis or delays in diagnosis of the endocrine disorder, and may continue even once patients are believed to be euthyroid.

Adult↗
PubMed1995

Induction of Fos protein in a model of closed head injury in rats.

The induction of Fos immunoreactivity in the pyriform cortex and the hippocampal formation after closed head injury was determined and compared to that seen following cortical needle injury in pentobarbital anaesthetized male rats. Robust Fos expression was observed in the ipsilateral pyriform cortex following both types of injury but was observed in the ipsilateral dentate gyrus only following closed head injury. Pretreatment with the NMDA receptor blocker MK-801 eliminated closed head injury induced Fos expression in the pyriform cortex and attenuated that seen in the hippocampus. Similar amounts of Fos expression were observed in urethane anaesthetized lactating and nonlactating rats following closed head injury. No gross behavioural impairments as reflected in body weight gain and locomotor activity were seen in animals subjected to closed head injury. These results demonstrate that as with other forms of brain damage, closed head injury at levels that produce no overt brain lesion nor gross behavioural impairment induce Fos expression in the pyriform cortex and the dentate gyrus which is dependent on the activation of NMDA receptors. Further, this response to brain injury is not modulated by lactation.

Animals↗
PubMed1995

The effect of in utero administration of buthionine sulfoximine on rat development.

Glutathione (GSH) is a tripeptide that is thought to be an essential cell component playing an important role as a cellular antioxidant and scavenger of free radicals. GSH depletion has been shown to render cells more sensitive to various insults. GSH has a protective effect. GSH levels can be decreased by inhibition of its synthesis with buthionine sulfoximine (BSO), which inhibits gamma-glutamylcysteine synthetase. Several studies have shown that treatment with BSO enhances the toxicity of some drugs and radiation. A previous study indicated that the effects of BSO on the developing embryo were short lived and did not persist to birth. In the above-mentioned study, mothers were treated with BSO only on days 10 and 11 of gestation. The objective of the present study was to determine the effects of BSO administration on GSH depletion throughout pregnancy on the developing rat. Timed pregnant Sprague-Dawley rats were placed on a liquid BioServ diet containing BSO starting on day 1 of pregnancy. The mothers received a daily dose of BSO ranging from 2 to 6 mmol/kg/24 h. The mothers were maintained on the diet until gestation day 21 when they were anesthetized with sodium pentobarbital and the pups delivered by Cesarean section. GSH levels were measured in brain and liver, and various parameters relating to development were assessed. A dose-response curve showed that a maximum depletion (86%) of GSH in the mother's liver was produced by the 6 mmol/kg dose of BSO. However, no change was seen in brain GSH levels of the mothers.(ABSTRACT TRUNCATED AT 250 WORDS)

Abnormalities, Drug-Induced↗
PubMed1995

Distribution of NADPH-diaphorase staining and light-induced Fos expression in the rat suprachiasmatic nucleus region supports a role for nitric oxide in the circadian system.

Nitric oxide serves as a messenger molecule in some neuronal systems that use glutamate as a transmitter and it has been shown that glutamate mediates the transmission of photic signals by retinal ganglion cell axons terminating in the hypothalamic suprachiasmatic nucleus, site of the circadian pacemaker in rodents. Recent experiments have demonstrated that pharmacological treatments which block nitric oxide synthesis by nitric oxide synthase prevent glutamate-induced phase shifts of the cell firing rhythm in suprachiasmatic nucleus slice preparation in vitro; similar treatments were found to inhibit light transmission to the suprachiasmatic nucleus as well as light-induced phase shifts in activity rhythms in vivo, implicating nitric oxide in circadian light signalling in vivo. There is limited information, however, about the presence and function of nitric oxide synthase-containing neurons within retinorecipient regions of the rodent suprachiasmatic nucleus. In the present study we used NADPH-diaphorase histochemistry and immunostaining for the nuclear phosphoprotein Fos to assess the co-distribution of nitric oxide synthase-containing neurons and light-responsive cells in the rat suprachiasmatic nucleus region. A strong convergence between NADPH-diaphorase-stained cell bodies and fibres and cells that expressed Fos in response to photic stimulation was noted in the anterior periventricular nucleus, suprachiasmatic preoptic nucleus, retrochiasmatic area, the inter-suprachiasmatic nucleus region, and the dorsal aspect of the optic chiasm, below the suprachiasmatic nucleus. A similar convergence between NADPH-diaphorase-stained fibres and Fos-immunoreactive cells was noted inside the suprachiasmatic nucleus, but the number of NADPH-diaphorase-stained elements found in this region was substantially low compared with that found in retinorecipient regions bordering the nucleus. In many cases both inside and outside the suprachiasmatic nucleus, the Fos-immunoreactive cells appeared to make direct contact with NADPH-diaphorase-stained cells or fibres, but no co-localization of Fos immunoreactivity and NADPH-diaphorase histochemical activity within individual cells was detected. Extensive co-distribution of NADPH-diaphorase-stained cells and fibres and cells that express Fos in response to photic stimulation in the suprachiasmatic nucleus region is in line with the hypothesis that nitric oxide participates in the mechanism mediating circadian light signalling in the suprachiasmatic nucleus. However, lack of co-localization of the two markers to individual cells rules out the possibility that retinorecipient cells in the suprachiasmatic region synthesize and release nitric oxide when photically-activated. Instead, the results support the possibility that photic stimulation triggers nitric oxide synthesis in nitric oxide synthase-containing neurons located near the photically-activated cells.

Animals↗
PubMed1995

Ultraviolet light entrains rodent suprachiasmatic nucleus pacemaker.

It has long been assumed that, in contrast to other vertebrates, mammals are ultraviolet blind. Recent evidence indicates, however, that the spectral sensitivity of the retina in rodents extends into the ultraviolet range. This finding, combined with reports that ultraviolet light can suppress nocturnal melatonin release and reverse the effect of short photoperiod on the gonads, invites speculation about the role of ultraviolet light in photoperiodic control of physiological and behavioral functions. One idea is that ultraviolet light participates in retinally mediated processes underlying photic entrainment of a pacemaker located in the hypothalamic suprachasmatic nucleus that generates circadian rhythms. Consistent with such a function, we now show that ultraviolet light is capable of inducing phase shifts in circadian rhythms in the rat and of inducing in the hypothalamic suprachiasmatic nucleus expression of the transcription factor Fos, a known cellular correlate of light-induced phase shifts of the hypothalamic suprachiasmatic nucleus pacemaker.

Animals↗
PubMed1995

Prolonged evaluation of epinephrine and normal saline solution injections in an acute ulcer model with a single bleeding artery.

BACKGROUND: Animal studies of epinephrine or normal saline solution injection for bleeding ulcers do not consistently demonstrate local tamponade effect. METHODS: We studied the change of bleeding rates of 28 acute gastric ulcers with a single bleeding artery in 10 dogs. Four injections of 1 mL epinephrine 1:10000 at 1 mm from the spurting artery (n = 7) were compared to four injections of normal saline solution 1 to 5 mL (n = 12) and to four dry needle sticks (n = 9). Bleeding rates were measured at initial arterial incision and at minutes 1, 5, 10, 15, 20, 25, and 30 after treatment. RESULT: Reductions in early blood loss to 24.3% +/- .05 of baseline occurred with saline solution, to 17.7% +/- .03 with epinephrine, and to 66.0% +/- 1.8 in controls (p < .05 for epinephrine and saline solution vs control). A tendency for saline solution injected ulcers to resume bleeding was identified, with late blood loss increasing to 26.9% +/- .05 of baseline, (saline solution vs control) compared to 7.7% +/- .02 in epinephrine injected ulcers (p < .05 vs control). CONCLUSIONS: The early acute hemostatic effect of injection therapy depends on local tamponade. The prolonged hemostatic effect is a combination of tamponade and vasoconstriction, with advantage of epinephrine over saline solution.

Animals↗
PubMed1995

p53 status of head and neck cancer: relation to biological characteristics and outcome of radiotherapy.

p53 status was investigated in 99 patients with squamous cell carcinoma of the head and neck region uniformly treated with accelerated radiotherapy and in whom tumour cell proliferation and DNA aneuploidy were assessed using bromodeoxyuridine (BrdUrd) incorporation and flow cytometry (FCM). Seventy-six percent of tumours were immunohistochemically positive for p53 protein, but heterogeneity was noticed both in the percentage of cells positive for p53 and in their level of expression. However, tumours which were either essentially all positive or all negative or showed sporadic positivity for p53 protein showed no differences in their level of aneuploidy, proliferation rate, tissue organisation or outcome with radiotherapy. There was a trend for those p53-positive tumours with the strongest expression to have more DNA aneuploidy and deregulation of proliferation organisation than weaker expressors; but there were no differences in proliferation rate or outcome of radiotherapy. These studies suggest that p53 protein stabilisation as assessed by immunohistochemistry does not have any major relationship with the biological characteristics and outcome of squamous cell cancer treated by accelerated radiotherapy.

Aneuploidy↗
PubMed1995

Measuring forearm blood flow and interpreting the responses to drugs and mediators.

Venous occlusion plethysmography has been widely used to study forearm blood flow. The principle of the technique is straightforward: the rate of swelling of the forearm during occlusion of venous return is used to assess the rate of arterial inflow. Provided that perfusion pressure (arterial blood pressure) remains constant, changes in flow reflect changes in smooth muscle tone in small arteries and arterioles. Local infusion into the brachial artery allows assessment of the direct effect of drugs on vascular tone and has been used to probe the roles of endogenous mediators. The technique is at its most powerful when dose-response relationships to different drugs or mediators within a single study are being compared but can also be used for comparison of responses to drugs between healthy control subjects and patient populations. However, when responses between groups are being compared, it is important to take into account the starting conditions of baseline blood flow and pressure. This article describes venous occlusion plethysmography, discusses the presentation and analysis of data (dose of drug or concentration? forearm blood flow or resistance?), and highlights certain potential problems and limitations of the technique as a means of studying disease states.

Blood Pressure↗
PubMed1995

Teleform scannable data entry: an efficient method to update a community-based medical record? Community care coordination network Database Group.

Community-based multi-disciplinary care of chronically ill individuals frequently requires the efforts of several agencies and organizations. The Community Care Coordination Network (CCCN) is an effort to establish a community-based clinical database and electronic communication system to facilitate the exchange of pertinent patient data among primary care, community-based and hospital-based providers. In developing a primary care based electronic record, a method is needed to update records from the field or remote sites and agencies and yet maintain data quality. Scannable data entry with fixed fields, optical character recognition and verification was compared to traditional keyboard data entry to determine the relative efficiency of each method in updating the CCCN database.

Chronic Disease↗
PubMed1994

Induction of Fos protein in the piriform cortex after brain injury in pentobarbital-anaesthetized rats: lack of effect of lactation.

The ability of lactation and progesterone administration to inhibit the induction of Fos protein in the piriform cortex after brain injury in pentobarbital-anaesthetized rats was assessed in three studies. Consistent with previous reports we found that brain injury-induced Fos expression in the piriform cortex could be eliminated by the administration of the non-competitive NMDA receptor antagonist MK 801 (4 mg/kg i.p.). Fos induction was not reduced, however, in lactating dams (days 7-9) post-partum or in progesterone-treated males. These results are not consistent with the hypothesis that suckling stimulation and progesterone have a direct effect at the NMDA receptor complex.

Anesthesia↗