PubMed Health⌕ Search

Biomedical subjects

R Sellar

Publications and source records attributed to R Sellar.

11 recordsLinked to original sources
PubMed1995

Gonadotropin-releasing hormone receptor messenger ribonucleic acid expression in rat ovary.

Rat GnRH pituitary receptor complementary DNA was used to isolate a truncated clone from a rat corpus luteum complementary DNA library that proved to be identical in sequence to the rat anterior pituitary GnRH receptor. The distribution of the GnRH receptor messenger RNA (mRNA) was then determined in rat ovary using in situ hybridization. GnRH receptor expression was investigated in cyclic female rats and in hypophysectomized immature female rats treated with either recombinant human FSH or human menopausal gonadotropin. The expression of LH receptor mRNA was determined in serial sections as an index of the health and differentiation of the follicles. In cyclic animals, GnRH receptor mRNA was detected in granulosa cells at varying stages of follicular development and in the corpus luteum. Ovaries from hypophysectomized animals expressed GnRH receptor mRNA in the granulosa cells of most follicles. The administration of FSH or human menopausal gonadotropin to hypophysectomized animals altered the distribution of GnRH receptor mRNA. During antral development, the signal was most abundant in medium-sized follicles not expressing LH receptor mRNA and showing signs of follicular atresia. However, healthy preovulatory follicles also expressed GnRH receptor mRNA. We conclude that the expression of the GnRH receptor gene in granulosa cells is 1) individually regulated for each follicle, 2) persists in the corpus luteum, and 3) expressed in atretic follicles.

Animals↗
PubMed1994

Single photon emission computed tomography in long-term survivors of adult brain tumours.

Sixteen patients with primary brain tumours were examined on average eight years after treatment with surgery or whole brain irradiation using standard clinical assessment, CT, a neuropsychological test battery, and single photon emission CT (SPECT) with 99mTc-exametazime. Seventeen lesions were discovered on inspection of SPECT images, 11 with x-ray CT. Quantitative assessment of tracer uptake compared with 16 matched healthy volunteers was consistent with the presence of lesions. Measurement of uptake in brain regions of the hemisphere not containing the primary tumour still showed significant reductions in patients. This may be due to remote direct effects of the tumour or, more likely, to the whole brain irradiation received. Psychometric performance on most tests was significantly impaired in the patient group and was correlated with abnormalities of tracer uptake to relevant brain regions.

Adult↗
PubMed1994

An experimental study to evaluate the accuracy of diencephalic and pallidal target localization using the Brown-Roberts-Wells stereotactic system and unreformatted axial GE8800 CT scanning.

An experimental study was undertaken to evaluate the accuracy with which the intercommissural line (IL) length and anterior-posterior commissural (AC-PC) plane could be selected using unreformatted axial CT8800 imaging. Using these reference points, the Schaltenbrandt and Bailey stereotactic atlas and the Brown-Roberts-Wells (BRW) stereotactic system 1.82 mm ball bearings were deposited at selected diencephalic and pallidal targets in cadaver brains. There were errors in both IL length (median 1.5 mm) and AC-PC plane (median forward angulation of 9 degrees) estimation. Ball bearing deposition into large nuclei such as the pulvinar and globus pallidus and those in proximity to the mid IL such as the nuclei ventro oralis anterior (Voa), ventro oralis posterior (Vop) and ventro intermedius (Vim) was generally good; however, localization of the relatively small intralaminar nucleus was poor. This study suggests that when the AC and PC are not well imaged on sagittal reformations of axial diencephalic CT scans estimation of the AC-PC plane and IL from axial CT scans may be accurate enough for anatomical localization of certain functional stereotactic targets. The implications of this experimental study to operative functional stereotaxy are discussed.

Biopsy↗
PubMed1994

Teaching image-guided stereotactic methodology and functional neuroanatomy of the thalamus and pallidum: a simple ex vivo technique.

A simple and cheap model that enables on site, ex vivo, but very practical, learning of frame-based image-guided stereotactic technique and methodology, and the functional anatomy of the pallidum and thalamus is described. Using a cadaver skull, a specially prepared, formalin-fixed cadaver brain, and a modified stereotactic probe application of a stereotactic frame to the cranium, fiducial point acquisition, target point acquisition, computation of both arc and probe depth settings, and verification of target point accuracy can all be practiced. If diencephalic targets are selected for targeting with ball bearings then section of the cadaver brains, and study of a human thalamic stereotactic atlas provides an excellent and clinically relevant method of learning functionally important thalamic and pallidal anatomy. The method and techniques are described for CT imaging using the Brown-Roberts-Wells frame, but they are equally applicable to other frame types.

Brain Mapping↗
PubMed1994

A simple practical classification of cerebral infarcts on CT and its interobserver reliability.

PURPOSE: To test the interobserver reliability of a simple method of classifying cerebral infarcts as seen on CT brain scans, which might allow differentiation of the site and size of the infarct from infarct swelling and hemorrhagic transformation. METHOD: Two experienced neuroradiologists independently reviewed 119 CT brain scans showing recent small to large cortical and subcortical cerebral infarcts and classified each for site and size, amount of swelling, and hemorrhagic transformation blind to clinical information. Six less experienced general radiologists in training classified 33 of the CT scans blind to clinical information. Interobserver agreement was calculated using unweighted kappa statistics. RESULTS: The kappa statistics between the two experienced neuroradiologists were: (a) 0.78 for site and size (95% confidence interval 0.69-0.87); (b) 0.8 for swelling (95% confidence interval, 0.68-0.92); and (c) 0.3 for hemorrhagic transformation (95% confidence interval, 0-0.77); indicating "good," "excellent," and "fair" agreement, respectively. Agreement for the less experienced radiologists was fair to excellent. CONCLUSION: The cerebral infarct morphologic classification is simple, quick, and reliable and therefore practical. It usefully distinguishes between infarcts of similar site and size but with different amounts of swelling and hemorrhagic transformation, thus facilitating study of factors such as the influence of drug treatment on infarct swelling, which might influence clinical outcome. Although developed for CT, it could be used equally for MR imaging and has applications in research and clinical practice.

Adult↗
PubMed1993

Accuracy of ventrolateral thalamic nucleus localization using unreformatted CT scans and the B-R-W system. Experimental studies and clinical findings during functional neurosurgery.

The accuracy with which the ventrolateral thalamic nucleus could be targetted using the BRW stereotactic system and unreformatted axial CT imaging was evaluated in cadaver brains mounted in a skull. Ball bearings (1.82 mm diameter) were placed in the nuclei ventro intermedius (Vim), ventro oralis anterior (Voa) and posterior (Vop) and the brains then sectioned, the locations of the ball bearings relative to the anterior (AC) and posterior commissures (PC) measured and evaluated with reference to a Schaltenbrandt and Bailey stereotactic atlas. Targetting of the ventrolateral thalamic region was frequently accurate (77%) but because of errors in estimation of the AC-PC plane (mean forward angulation of 9 degrees) some ball bearings were placed too deeply in the Fields of and Forel, zona incerta and rostral subthalamic nucleus. Ventrolateral thalamotomy using the BRW stereotactic system and unreformatted axial CT imaging was undertaken in six patients with tremor due to a range of pathologies. The tremor was abolished or altered in four patients whilst no lesion was made in the other two patients since no site that reduced the tremor, could be located. The surgical and clinical implications of this study are discussed.

Diencephalon↗
PubMed1992

Phase II study of tauromustine in malignant glioma.

46 eligible patients with either anaplastic astrocytoma (AA) or glioblastoma (GBM) and clinical and computed-tomography-confirmed relapse following primary surgery and radiotherapy received oral tauromustine 130 mg/m2 every 5 weeks. A prospective design allowed for concurrent assessment of both clinical and radiological responses and drug toxicity. 41% of patients improved clinically whilst 46% improved radiologically with 3 complete, 7 partial and 7 minimal responses (WHO criteria). Toxicity included grade III or IV gastrointestinal side-effects (15%), grade III or IV leukopenia (24%) and grade III and IV thrombocytopenia (44%). In 9 clinically responding patients, haematological toxicity led to discontinuation of treatment. All patients were followed-up until death and second-line chemotherapy was not used. Median post-treatment survival was 26 weeks for patients with GBM and 57 weeks for patients with AA. Overall 2-year survival rate was 69% for AA and 23% for GBM. Tauromustine given at the time of relapse has demonstrable antitumour activity in patients not previously treated with chemotherapy.

Adult↗
PubMed1992

Epileptogenic anaplastic astrocytoma imaged only by T2-weighted magnetic resonance studies: clinical and surgical implications.

The case of a 28-year-old woman who presented with focal sensory seizures and later developed mild sensory loss in the face and hand is described. An EEG, two contrast-enhanced CT and non-enhanced T1-weighted magnetic resonance (MR) scans were normal, but T2-weighted MR scans revealed a lesion measuring 3 x 2 cm in the mid-rolandic region. This lesion did not enlarge over a 6-month period. Resection of the abnormal gyrus was guided by electrocorticography and histology revealed an anaplastic astrocytoma. Although there was resolution of the facio-digital sensory loss postoperatively the frequency and pattern of the partial sensory seizures was unchanged. The neuroradiological and histological findings in this case highlight the difficulties concerning the indications for surgical intervention in adult patients who present with epilepsy and have lesions visualized only on magnetic resonance imagery.

Adult↗
PubMed1990

Low back pain.

Explore the source record for details and available documents.

Back Pain↗
PubMed1987

Gastric and periurethral metastases from seminoma testis.

A case of seminoma testis with metastases to periurethral tissue and gastric submucosa is described. Response to treatment with irradiation and chemotherapy was good. Regression of the unusually sited tumour masses is demonstrated by barium meal and computed tomography. A brief review of gastric metastases is presented.

Adult↗