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Biomedical subjects

A J Gray

Publications and source records attributed to A J Gray.

At least 19 recordsLinked to original sources
PubMed2001

Olfactory identification is impaired in clinic-based patients with vascular dementia and senile dementia of Alzheimer type.

AIMS: It is now well established that there are abnormalities in the sense of smell in patients suffering from Alzheimer's disease (AD). They have both raised olfactory thresholds and impaired odour identification. The situation in vascular dementia is unclear. We used the University of Pennsylvania Smell Identification Test (UPSIT), a 40-item, forced choice, cued, 'scratch-and- sniff' test, to examine olfactory identification in vascular dementia and to determine whether it would differentiate the disorder from AD and normal elderly. METHODS: We investigated three matched subject groups: 13 people having a Cambridge Examination for Mental Disorders in the Elderly (CAMDEX) diagnosis of definite senile dementia of Alzheimer type, 13 having a CAMDEX diagnosis of definite vascular dementia and 13 non-cognitively impaired controls. The subjects were then tested with the UPSIT in their own home by an independent blind researcher to see if the test could distinguish the different diagnostic groups in this setting. RESULTS: The median UPSIT score was 30 (out of a maximum of 40) for controls, 12 for the vascular group and 15 for the AD group. The difference was significant (p = 0.05) between both demented groups and the normal controls. Similarly there was a significant difference in the UPSIT score between the AD group and controls (p = 0.001) and between the vascular dementia group and controls (p = 0.001), but there was no significant difference between the AD group and the vascular dementia group. The UPSIT score correlated strongly with the degree of cognitive impairment as measured by the CAMCOG (r(s) = 0.683, p = 0.01) CONCLUSIONS: Patients with vascular dementia had a similar degree of olfactory impairment to those with AD. The UPSIT successfully differentiated between dementia patients and normal elderly British subjects tested in their own homes. The UPSIT did not differentiate between those with AD and vascular dementia.

Aged↗
PubMed2001

An evaluation of semiautomatic approaches to contour segmentation applied to fungal hyphae.

Semiautomatic image analysis techniques are particularly useful in biological applications, which commonly generate very complex images, and offer considerable flexibility. However, systematic study of such methods is lacking; most research develops fully automatic algorithms. This paper describes a study to evaluate several different semiautomatic or computer-assisted approaches to contour segmentation within the context of segmenting degraded images of fungal hyphae. Four different types of contour segmentation method, with varying degrees and types of user input, are outlined and applied to hyphal images. The methods are evaluated both quantitatively and qualitatively by comparing results obtained by several test subjects segmenting simulated images qualitatively similar to the hyphal images of interest. An active contour model approach, using control points, emerges as the method to be preferred to three more traditional approaches. Feedback from the image provider indicates that any of the methods described have something useful to offer for segmentation of hyphae.

Algorithms↗
PubMed1999

Air emboli with Haemaccel(R)

We report two cases of venous air embolism which occurred in association with infusion of Haemaccel(R) using a pressure bag. As a result of these incidents, we performed a study that showed that up to 45 ml of air can be infused into a patient from a pressurised Haemaccel(R) plastic bottle using a standard administration set. We also demonstrated that the volume of air infused was influenced by the type and size of the pressure bag and the warming of the Haemaccel(R) plastic container.

Aged↗
PubMed1999

Stevens-Johnson syndrome in patients on phenytoin and cranial radiotherapy.

The use of phenytoin as a prophylactic anticonvulsant after brain surgery, particularly for brain tumors, is a common practice, regardless of whether the patient has a previous history of convulsions. This treatment policy assumes that the benefits exceed the risks. Four cases are described of adverse reactions to phenytoin during the concomitant use of cranial radiotherapy. In one patient this proved fatal. There is increasing anecdotal support in the literature for a synergistic effect between phenytoin therapy and cranial radiotherapy that can result in the life-threatening Stevens-Johnson syndrome. While the association is uncommon, four cases within 24 months in one department suggest that the routine use of postoperative phenytoin as a prophylactic anticonvulsant in the absence of a history of seizures may not be warranted, particularly if the patient is to receive cranial radiotherapy.

Adult↗
PubMed1998

Thrombin stimulates fibroblast procollagen production via proteolytic activation of protease-activated receptor 1.

Thrombin is a multifunctional serine protease that has a crucial role in blood coagulation. It is also a potent mesenchymal cell mitogen and chemoattractant and might therefore have an important role in the recruitment and local proliferation of mesenchymal cells at sites of tissue injury. We hypothesized that thrombin might also affect the deposition of connective tissue proteins at these sites by directly stimulating fibroblast procollagen production. To address this hypothesis, the effect of thrombin on procollagen production and gene expression by human foetal lung fibroblasts was assessed over 48 h. Thrombin stimulated procollagen production at concentrations of 1 nM and above, with maximal increases of between 60% and 117% at 10 nM thrombin. These effects of thrombin were, at least in part, due to increased steady-state levels of alpha1(I) procollagen mRNA. They could furthermore be reproduced with thrombin receptor-activating peptides for the protease-activated receptor 1 (PAR-1) and were completely abolished when thrombin was rendered proteolytically inactive with the specific inhibitors d-Phe-Pro-ArgCH2Cl and hirudin, indicating that thrombin is mediating these effects via the proteolytic activation of PAR-1. These results suggest that thrombin might influence the deposition of connective tissue proteins during normal wound healing and the development of tissue fibrosis by stimulating fibroblast procollagen production.

Connective Tissue↗
PubMed1998

Long-term results of accelerated radiation treatment for advanced head and neck cancer.

BACKGROUND AND PURPOSE: This report presents long-term follow-up data from a prospective but unrandomized trial of a continuous 3.5-week course of accelerated radiation treatment (ART) used as primary treatment for patients with loco-regionally advanced head and neck cancer. MATERIALS AND METHODS: Ninety-three patients in three centres in New Zealand and Australia were treated with ART (59.40 Gy in 33 fractions over 24-25 days). Their disease originated from three anatomical regions (oral cavity, 35 patients; pharynx, 31 patients; larynx, 27 patients). Seventy-nine of these patients had stage III or IV cancers. RESULTS: Follow-up ranged from 68 to 203 months (median 139 months). Loco-regional (LR) failure occurred in 52 patients leading to a 10-year actuarial expectation of LR control of 38%. The actuarial expectation of LR control at 10 years was highly dependent on stage and for stage III, IVA and IVB patients it was 57+/-8.1%, 32+/-1.7% and 7+/-0.5%, respectively. Multivariate analysis could not confirm an independent impact of primary site or histological differentiation on LR failure. Two patients died of acute toxicity of treatment and six patients developed grade 3/4 late complications affecting soft tissues only, yielding an actuarial expectation of complications of this severity at 5 years of 9%. No cases of osteoradionecrosis or myelitis were observed. CONCLUSION: This ART, which has proved easy to use at a number of large and small centres, has produced encouraging long-term LR control at a cost of limited soft tissue morbidity.

Adolescent↗
PubMed1998

Towards automatic cell identification in DIC microscopy.

A general method is proposed for constructing templates of cells in differential interference contrast (DIC) microscopy. This takes account of the optics which generate DIC images, and is applicable to both transparent and semi-transparent cells of simple and complex shapes. Then, a template matching methodology is presented, which uses fast Fourier transforms to fit templates of a range of sizes and orientations to images. For illustration, this is used to automatically identify and measure individual Candida yeast cells in clusters.

Automation↗
PubMed1998

Out of hospital cardiac arrest and associated injury.

Three patients are described who sustained injuries around the time of a collapse that led to out of hospital cardiac arrest. In this group of patients the importance of taking a complete medical history and recording the circumstances of the syncopal episode cannot be overemphasised. If cardiac output is successfully restored the possibility of occult traumatic injury must be considered in high risk patients.

Aftercare↗
PubMed1997

Radiation therapy for retinoblastoma: a retrospective review of 120 patients.

PURPOSE: To characterize the patient population and treatment outcomes in patients with Retinoblastoma (RB) referred for External Beam Orbital Radiotherapy (EBORT) to King Faisal Specialist Hospital & Research Centre (KFSH&RC), Riyadh, Saudi Arabia from 1976 to 1993. METHODS AND MATERIALS: A retrospective study of 120 patients with RB affecting a total of 192 eyes. Patients were divided into three groups. Group A are 60 patients (64 eyes) treated with EBORT to the intact eye to preserve vision. Reese-Ellsworth (RE) Staging was: 1: 12%; 2: 10%; 3: 12%; 4: 23%; and 5: 43%. Twenty-eight patients (47%) also received Vincristine, Adriamycin, and Cyclophosphamide chemotherapy (C/T). Mean follow-up, per patient, was 48.5 months. Standard treatment until 1992 was 45 Gy in 12 fractions of 3.75 Gy, three times weekly over 18 days. Assuming the alpha/beta ratio for early effects and tumor control at 10, Tk = 21 days, Tpot = 5 days, then the Biological Equivalent Dose (BED) was 62 Gy10 for early effects, and 101 Gy3 for late effects. Group B are 28 patients (28 eyes) treated for curative intent with EBORT to the orbit for locally advanced disease, usually after enucleation (24 eyes). Nineteen patients (83%) also had C/T. Mean follow-up was 22.6 months. Group C are 37 patients with advanced disease treated with radiotherapy for palliation. Seventeen (46%) also received C/T. Mean follow-up was 11.7 months. RESULTS: Group A-following EBORT useful vision was retained in RE Stage 1 to 5: 7 of 7, 6 of 6, 4 of 8, 10 of 15, and 7 of 28 eyes, respectively. There was no significant difference between patients who received adjuvant chemotherapy and those who did not. Complications included cataract (27%), retinopathy (25%), vitreous hemorrhage (19%), and orbital deformities (11%). In Group B the local control rate was 71%. In Group C, 10 (27%) of the 37 patients were alive at last contact, and 27 (73%) were either terminal or dead of disease. None of Group A or B patients had positive CSF cytology, bone scan, or bone marrow examination. In Group C 19% had positive CSF cytology, and bone marrow, and 14% had a positive bone scan. CONCLUSIONS: 1) EBORT preserved useful vision in a significant proportion of patients even in eyes with advanced RE Stage RB, but longer follow-up is likely to reveal an even higher complication rate with this regime. 2) High dose per fraction probably contributed to the increased complications. 3) Chemotherapy did not demonstrate any effect on retaining vision in this study. 4) For disease that is confined to within the eye clinically and radiologically, invasive procedures for CSF cytology, bone marrow examination, and bone scan do not seem warranted. 5) The optimum technique, fractionation, and dosage for RB is still not well defined.

Child↗
PubMed1997

The ligamentum teres of the hip: an arthroscopic classification of its pathology.

Pathology of the ligamentum teres is rarely diagnosed. We describe the classification of the lesions seen at hip arthroscopy based on a group of 20 patients. Three groups are noted: complete rupture, partial rupture, and the degenerate ligamentum. The complete ligamentum teres rupture group had a history of either major trauma or surgery and had a high incidence of other hip pathology such as labral tears and articular damage. The partial ligamentum rupture group presented with a long history of ill-defined hip pain. Minor associated hip abnormalities were seen at arthroscopy. Degenerate ligamentum teres rupture presented with symptoms of the underlying osteoarthritis. Debridement or washout was performed but, at 2 years, patients had severe persistent symptoms or had had a joint replacement.

Adult↗
PubMed1996

Treatment results for 149 medulloblastoma patients from one institution.

PURPOSE: Retrospective analysis of patients with medulloblastoma to determine the effectiveness of previous treatments for medulloblastoma and plan for future management strategies. METHODS AND MATERIALS: During the period March 1976 to December 1991, 172 patients with cerebellar medulloblastoma were referred to King Faisal Specialist Hospital and Research Center. One hundred and forty-nine patients were treated with curative intent. There were six postoperative deaths, and 10 patients planned for radiotherapy treatment failed to complete the prescribed course. One hundred and thirty-three patients completed a course of radiotherapy after surgery. Adjuvant chemotherapy was not used routinely (six patients only). Tumors were staged retrospectively according to the Chang staging system. There were no T1 patients, 32 patients had T2 tumors, 76 had T3 tumors, and 29 had T4 tumors. The T stage could not be allocated in 12 patients. Ninety-nine patients required a shunting procedure either pre- or postoperatively. Forty-six patients had complete resection of tumor, 91 had incomplete resection, and 6 patients had biopsy only. The extent of resection could not he determined in six patients. The median radiation dose for the whole brain was 34 Gy, spine 32.5 Gy, and posterior fossa 52.8 Gy. Fraction sizes ranged from 1.7-1.8 Gy for craniospinal fields and 2 Gy for the posterior fossa boost. Seventy percent completed the prescribed course within 7 weeks. RESULTS: Actuarial survival for the whole group of 149 patients was 53% at 5 years and 38% at 10 years. On univariate analysis, patients with T2 tumors did significantly better as compared to patients with T3 and T4 tumors. Survival of patients who had clinical and radiological complete resection of tumor at surgery was significantly better than patients with incomplete tumor removal. The presence of a ventriculoperitoneal (VP) shunt had a significant negative impact on survival. Treatment failure by site was analyzed with respect to the radiation dose. Doses greater than 50 Gy for the posterior fossa, and greater than 30 Gy for craniospinal axis, resulted in significantly better survival. On multivariate analysis, the only significant prognostic factor was the presence of a VP shunt in patients with T2 tumors. CONCLUSION: T stage, VP shunt, radiation doses and extent of surgery were important prognostic factors. In this study, radiation doses of more than 50 Gy to the posterior fossa and 30 Gy to the craniospinal axis resulted in improved survival.

Adolescent↗
PubMed1996

Pericardial metastasis in carcinoma of the uterine cervix.

Cardiac metastasis from gynecological malignancies is rare. Only six cases of carcinoma of the uterine cervix have been reported where the diagnosis of malignant pericardial effusion was made antemortem. The treatment of neoplastic pericardial effusion is controversial; both surgical and nonsurgical treatments are advocated. We present a patient with pericardial effusion secondary to carcinoma of the cervix and recommend subxiphoid pericardial fenestration for reliable long-term control of malignant effusion.

Female↗