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Biomedical subjects

D Royston

Publications and source records attributed to D Royston.

At least 37 records · Page 2Linked to original sources
PubMed2001

Solitary fibrous tumour of the parotid gland.

Solitary fibrous tumours are rare tumours originally described in the pleura. More recently there have been reports of these tumours arising at other sites including the parotid region. They are characterized histologically by a variety of growth patterns that can be confused by the unwary with other benign or malignant tumours particularly sarcomas. We present a case occurring in the pre-auricular region which presented diagnostic difficulties.

Adult↗
PubMed2001

Efficacy and cost-effectiveness of bronchial arterial embolisation in the treatment of major haemoptysis.

OBJECTIVE: To determine the efficacy and cost-effectiveness of bronchial artery embolisation (BAE) in the treatment of major and massive haemoptysis in HIV-positive and negative patients with pulmonary inflammatory disease. METHODS: A retrospective review of patients admitted over a period of 24 months to Wentworth Hospital with major haemoptysis treated using BAE. RESULTS: Eighty-seven patients were treated (77 males, 10 females). Bilateral disease was present in 50 patients (57%). Thirty-two patients were HIV-positive (37%). Embolisation was successfully performed in 77 patients (88.5%), and failed for technical reasons in 10 patients (11.5%). There was only one procedural complication. Fifty-seven patients had a successful outcome, with cessation of haemoptysis within 24 hours (66.5%). Haemoptysis continued in 30 patients (34%) (20 patients embolised and the 10 patients who had failed procedures). Fourteen of these patients (16%) required lobectomy or pneumonectomy as an emergency procedure. Five patients (5.7%) died from respiratory failure or pulmonary haemorrhage. Twenty-four HIV-positive patients were successfully embolised. Costing of BAE, including a 2-day ICU and 3-day ward stay, was R6,720; together with surgical resection the cost was R14,170. CONCLUSIONS: BAE is an effective treatment for major and/or massive haemoptysis in patients with pulmonary inflammatory disease who are not surgical candidates. Patients who are HIV-positive are able to tolerate the procedure well.

Adult↗
PubMed2000

[Effect of fructose-1,6-diphosphate on myocardial purin and pyrimidin metabolism during coronary artery bypass grafting surgery].

During ischaemia, the glycolytic pathway (Embden-Meyerhof) is up regulated in an attempt to produce ATP anaerobically. However, this is short-lived due to negative feedback on the key glycolytic enzyme phosphofructokinase by accumulating lactate. Fructose-1,6-diphosphate (FDP), a high energy intermediary metabolite of this pathway, is unique in that is enters glycolysis distal to this inhibitory site. Exogenously administered FDP should therefore theoretically yield ATP independent of lactate accumulation and thereby ameliorate ischaemic injury. Clinical benefit has been shown in coronary artery bypass grafting (CABG) surgery, congestive cardiac failure and adult respiratory distress syndrome. Ischaemia-reperfusion injury induced by cardiopulmonary bypass (CPB) presents clinically as an impairment of myocardial function in the postoperative period. At a cellular level this reflects myocardial metabolic changes and nucleotide degradation (directly linked to high energy phosphate turnover). Quantification of myocardial nucleotide catabolite release therefore provides useful information regarding intermediary metabolism and cytoprotection conferred to myocardial (inosine, uridine) and endothelial (hypoxanthine) tissue. The authors investigated the myocardial cytoprotective effects of FDP in 16 patients scheduled for elective CABG surgery. Aortic and coronary sinus blood were collected directly into liquid nitrogen and analysed by high performance liquid chromatography prior to CPB and at different time points after reperfusion. FDP was administered intravenously in 8 patients and 5% dextrose was administered in 8 other patients. Analysis of transmyocardial (coronary sinus-aortic) nucleotide metabolite levels showed increased release of inosine, hypoxanthine and uridine in both the FDP and the control groups following reperfusion. However, compared to baseline (pre-aortic clamping) values, hypoxanthine and inosine concentrations were significantly elevated at 0, 1, 5 and 10 minutes following reperfusion in the control group. This was in contrast to earlier recovery to baseline levels (after 5 minutes of reperfusion) in the FDP group. Furthermore, when compared to control group, the hypoxanthine and inosine concentrations were significantly decreased by FDP treatment. Uridine concentrations were significantly elevated at 1 and 5 minutes in the control group and no significant change was observed in the FDP group. In conclusion, these data suggest that FDP, through an intermediary metabolic effect, may contribute to myocardial and endothelial cytoprotection during the ischaemic insult of cardiac surgery.

Adult↗
PubMed2000

Cerebral blood flow changes in rhinogenic subdural empyema and the role of hyperaemia in brain swelling.

BACKGROUND: Previous studies have demonstrated that rhinogenic subdural empyema (SDE) generally has a good prognosis. Most patients are admitted with an altered level of consciousness or significant neurological deficit, but eventually have a good outcome. It is well known that intra-operative brain swelling may occur with subdural empyema. OBJECTIVE: To define cerebral blood flow (CBF) dynamics and determine the role of cerebral hyperaemia, if any, in intracranial SDE. METHODS: CBF dynamics were assessed in five patients (mean age 13.2 +/- 2.2 years) with unilateral rhinogenic convexity SDE documented on computer tomography (CT). Regional cortical blood flow (rCBF) was measured using a thermo-coupled sensor placed on the cortex at the time of surgery. Dynamic CT scans were performed to assess cerebral blood volume (CBV) quantitatively, while transcranial Doppler ultrasonography (TCD) was used to measure cerebral blood flow velocities (CBF velocities) both pre- and post-operatively for 21 days. The opposite 'normal' hemisphere served as a control for each patient. RESULTS: Post-operative rCBF and CBF velocities in the pathological hemisphere progressively increased to plateau at 96 hours. Cerebral blood volume was increased bilaterally, but to a greater extent in the pathological hemisphere and more so in grey than white matter. These haemodynamic changes, though clinically significant did not reach statistical significance (p>0.05). CONCLUSION: Our results suggest that the accompanying brain swelling in rhinogenic SDE is a complex event, with reactive cerebral hyperaemia possibly playing neuroprotective role. Furthermore, unilateral convexity empyema causes bilateral cerebral haemodynamic changes. Future studies are necessary to define the aetiology of brain swelling in intracranial SDE.

Adolescent↗
PubMed1999

Malignant lymphoma of the cervix. An unusual presentation and a rare disease.

Malignant lymphomas arising in the uterus are uncommon and are more commonly seen in the cervix than the corpus. Involvement of the cervix as part of a systemic lymphoma is more common than primary lymphoma, but the cervix as the site of presentation is unusual. We report two cases of malignant lymphoma of the cervix. The first patient, a 52-year-old woman, was referred to colposcopy following persistent low grade dyskaryosis on cervical cytology. At colposcopy a Lletz biopsy was performed and a diagnosis of CIN 1 and focal CIN 2 was made. In addition the subepithelial zone revealed a non-Hodgkin's (NHL) B-cell follicular lymphoma. The patient was subsequently staged as NHL Stage 3E. The second patient, a 35-year-old woman, was referred to the gynaecology department with a history of abnormal vaginal bleeding and two abnormal smears. Subsequent cervical biopsy revealed a high grade, large cell, malignant lymphoma, diffuse, B-cell. The patient was staged as Stage IE. Primary lymphoma of the uterine cervix as illustrated in the second case is very unusual. One case had negative cytology and one case had abnormal cells of uncertain origin. This highlights the difficulty of diagnosing cervical lymphoma, a rare but treatable malignancy, on cytology and suggests that cervical biopsy is needed for the confirmation of the diagnosis.

Adult↗
PubMed1999

Double fluorescent-amplification refractory mutation detection (dF-ARMS) of the factor V Leiden and prothrombin mutations.

Simultaneous fluorescent [F] detection of the factor V Leiden (G1691A) and the prothrombin 3'-untranslated region (G20210A) mutations were performed in a single tube polymerase chain reaction (PCR). Amplification refractory mutation detection system (ARMS) formed the basis of this assay design. Fluorescent-labelled primers incorporated into amplicons during the reaction facilitated detection directly by GeneScan analysis without further manipulation. To test the efficacy of this double [F]-ARMS (dF-ARMS) method, 48 patients with unexplained thrombotic tendencies were investigated for their factor V Leiden and prothrombin genotypes. These results corresponded exactly with data achieved using the more conventional methods of restriction fragment length polymorphism (RFLP)-PCR and direct DNA sequencing. Three out of the 48 patients in this group were found to be compound heterozygotes.

Alleles↗
PubMed1998

Aprotinin versus lysine analogues: the debate continues.

The decision to use any pharmacologic intervention inevitably rests on balancing the efficacy and safety of the intervention. The advent of the acquired immunodeficiency syndrome epidemic greatly increased awareness of transfusion-related illnesses and focused attention on methods to prevent the need for blood and blood products. This has led, especially in the last decade, to increased use of drugs to help reduce perioperative bleeding. This chapter focuses on the lysine analogues and aprotinin as the serine protease inhibitor currently available in clinical practice. Both groups of compounds have recently shown promise in reducing surgical bleeding. However, the reader will notice that none of these agents are new; they have all been available for more than 30 years. What is new is their use in preventing bleeding. We therefore have considerable knowledge regarding the safety of these compounds. The first part of this review will compare the actions of these two types of agents on the processes related to thrombosis, hemostasis, and fibrinolysis. This is followed by a comparison of the efficacy of each intervention and any dose-response relationship. This section highlights the reported reduction in postoperative bleeding with both classes of agent. There is, however, no obvious or consistent reduction in the transfusion of blood and blood products in patients given lysine analogues. In contrast, there is a consistent reduction in the need for blood transfusions in patients given aprotinin therapy. The next major section will discuss the evidence to suggest that these drugs may, because of their known effects on the processes related to inflammation, hemostasis, and cellular repair, contribute to an improvement or worsening of outcome after cardiac operations. In particular, this section focuses on the antiinflammatory actions and modifications in vascular tone associated with aprotinin therapy. These effects may be related to improved outcome in patients by reducing the incidence of permanent neurologic deficit or stroke after heart operations, as well as inhibiting pulmonary vascular hyperreactivity and hypertension in susceptible individuals. Finally, this brief review discusses the safety issues that have been raised in regard to each of these classes of agents, specifically problems associated with abnormal renal function, hypersensitivity reactions, and thrombotic complications.

Aminocaproic Acid↗
PubMed1998

Cardiopulmonary effects of 7.2% saline solution compared with gelatin infusion in the early postoperative period after coronary artery bypass grafting.

OBJECTIVE: We report a clinical study on the use of 7.2%, 2400 mOsm/L, hypertonic saline solution compared with gelatin in early postoperative period after coronary artery bypass surgery. METHODS: Two groups (n = 10 each) received 5 ml/kg of either saline solution or gelatin over 1 hour. Cardiac index, central venous pressure, pulmonary capillary wedge pressure, systemic and pulmonary vascular resistance indices, arterial oxygen tension, plasma osmolarity, electrolytes, and urinary output were recorded before starting the infusion and subsequently at 10, 30, 60, 90, 120, 240 and 600 minutes. Plasma creatinine, urea, electrolytes, urinary volume, and sodium excretion were measured at 12 and 24 hours. RESULTS: There were no significant demographic or operative difference between the groups. Patients receiving saline solution had a larger diuresis at 12 (p = 0.0008) and 24 hours (p = 0.002), with less positive balance at 12 hours (p = 0.0008). The group receiving saline solution had better cardiorespiratory recovery with shorter extubation time (p = 0.033), and earlier increase in cardiac index with a positive correlation between plasma sodium content and cardiac index. Maximum increase in cardiac index (+31%) occurred at 60 minutes (p = 0.025) associated with 8% increase in plasma sodium content (r = 0.51, p = 0.01), without a concomitant rise in pulmonary capillary wedge pressure. The group receiving gelatin had a linear increase in cardiac index with increasing pulmonary capillary wedge pressure, reaching +16% from baseline by 90 minutes. Compared with the gelatin-treated group, patients receiving saline solution had unchanged systemic vascular resistance index but a significantly lower pulmonary vascular resistance index with a negative correlation to plasma sodium content. There was no difference in levels of urea and creatinine. No side-effect attributable to the use of saline solution was observed.

Coronary Artery Bypass↗
PubMed1998

Potential therapeutic applications of fructose-1,6-diphosphate.

Ischaemia-related tissue injury is the leading cause of death in developed countries. Drugs that can reduce ischaemic injury would be beneficial in treatment of myocardial infarction (MI), surgical trauma and stroke. Fructose-1,6-diphosphate (FDP) is a key intermediate in anaerobic glycolysis and is the product of the major regulatory enzyme in the pathway (phosphofructokinase). Preclinical and clinical data suggest that FDP has substantial cytoprotective effects in a variety of ischaemia-reperfusion injury scenarios. Evidence indicates that FDP has a direct effect on ATP pools, reduces ischaemia-induced tissue damage and has positive inotropic effects on heart function. The clinical data suggest that FDP may be a useful drug in a variety of ischaemic and inflammatory clinical settings where acute management of tissue injury is desired. Potential uses include: iv. administration for the reduction of ischaemic injury in sickle cell anaemia, bypass surgery, congestive heart failure, myocardial infarction, as well as organ preservation in transplants.

Journal Article↗
PubMed1998

Patient selection and anesthetic management for early extubation and hospital discharge: CABG.

Three model systems have been described that may facilitate an increase in the numbers of patients passing through the hospital within the resource allocation available: (1) early fast-track extubation, < 3 hours after surgery, (2) planned intensive care unit discharge < 18 hours, and (3) early hospital discharge < 5 days. Thus far, studies have not clearly identified patient group or risk demonstrating a need for prolonged intubation or delayed intensive care unit and hospital length of stay. It thus appears appropriate to suggest that all patients be considered suitable for early extubation, mobilization, and hospital discharge. An increase in the proportion of patients eligible for a more rapid, but safe, progression through their operative procedures may be facilitated by pharmacologic intervention or alteration in anesthetic technique. Prevention of adverse perioperative myocardial outcome by inhibition of stress responses and careful control of intraoperative cardiovascular variables is most easily achieved by high thoracic (C7-T1) epidural conduction block or by a high-dose opioid anesthetic technique using remifentanil. The ultrashort action of remifentanil facilitates the ability to plan and control the period of recovery of spontaneous ventilation and extubation while providing profound reduction of intraoperative stress responses and hemodynamic stability. Safe extubation requires that the patient be alert and cooperative, be hemodynamically stable and warm, is not bleeding, and has adequate respiratory function. Interventions with anti-inflammatory and hemostatic agents such as the serine protease inhibitor aprotinin or with corticosteroids can have a major impact on achieving the criteria needed to ensure rapid discharge from the intensive care unit.

Analgesics, Opioid↗