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Biomedical subjects

M Cassidy

Publications and source records attributed to M Cassidy.

At least 19 recordsLinked to original sources
PubMed1996

Comparison of high-resolution endoluminal sonography to video endoscopy in the detection and evaluation of esophageal varices.

High-resolution endoluminal sonography (HRES) was used to image and measure esophageal varices in control subjects and patients with portal hypertension and compared with endoscopic findings. Nine control patients and 68 patients with known cirrhosis or noncirrhotic portal hypertension underwent videotaped HRES and videotaped esophagoscopy (EGD). Two blinded investigators reviewed the videotapes to determine the presence and size of the largest esophageal varix in each patient. The largest varix by HRES was measured with the esophagus at rest at a point where the varix appeared most circular. The largest varix seen on EGD was graded on a 5-point scale. All nine of the control patients were correctly identified by both EGD and HRES as grade I (no varices). Eight of the 10 patients with no varices seen on EGD had varices identified by HRES. The interobserver correlation for HRES was r = .88 and for EGD was r = .79. The correlation between EGD and HRES was r = .50. High resolution endoluminal sonography allows quantitative measurement of variceal size, is a more sensitive and reproducible imaging modality than esophagoscopy for the detection and sizing of esophageal varices. There is poor correlation between monographic measurement and endoscopic grading of esophageal varices. Assessment of esophageal variceal presence and the measurement of variceal size by high resolution endoluminal sonography is an accurate, reproducible method of determining the size of esophageal varices.

Adult↗
PubMed1995

Serum neuron-specific enolase and immunohistochemical markers of neuroendocrine differentiation in lung cancer.

An enzyme immunoassay for serum neuron-specific enolase (NSE) was evaluated with respect to analytical performance and clinical utility and compared with immunohistochemical evaluation of neuroendocrine differentiation. Values obtained agreed well with values obtained using a radioimmunoassay method giving a correlation coefficient of 0.934. Analytical performance of the enzyme immunoassay was good but the diagnostic sensitivity of 82% in extensive and 67% in limited disease was insufficient for serum NSE to be of value in the diagnosis of small cell lung cancer (SCLC). Serum NSE decreased significantly in 11 of 15 patients with SCLC following institution of chemotherapy. Classification of lung cancers into SCLC and non small cell lung cancer (NSCLC) types is largely based on tumour morphology. Neuroendocrine differentiation may not be morphologically evident. Immunohistochemical staining of tumour tissue with markers of neuroendocrine differentiation, i.e. NSE (both monoclonal and polyclonal antibodies) Leu 7, Chromogranin A and P G P 9.5 was performed in both patients with SCLC and NSCLC. 38 per cent of patients with NSCLC had both raised serum NSE and positive NSE (polyclonal) immunoperoxidase staining of lung tissue. A further 35 per cent of patients showed a raised serum NSE or positive immunohistochemistry but not both. The presence of two positive immunoperoxidase markers in lung tissue has been suggested as an indicator of responsiveness to chemotherapy in NSCLC patients. A number of factors may affect immunohistochemical positivity in tissue sections and the additional use of a serum marker may better define chemotherapy responsive groups.

Adult↗
PubMed1994

Ameloblastoma of attached gingiva.

A case of a rare extra-osseous ameloblastoma is presented. It meets identical histological criteria as intra-osseous ameloblastoma, but its clinical presentation and behaviour are very different. It is non-invasive and may be locally excised without recurrence.

Ameloblastoma↗
PubMed1994

KP-1: not a specific marker. Staining of 137 sarcomas, 48 lymphomas, 28 carcinomas, 7 malignant melanomas and 8 cystosarcoma phyllodes.

This study documents the reactions of the monoclonal antibody KP-1, which detects histiocytes in paraffin sections, with 137 sarcomas, 48 lymphomas, 28 carcinomas, 7 malignant melanomas and 8 cystosarcoma phyllodes. The soft tissue sarcomas had been previously immunophenotyped. Positive staining was obtained in all categories of sarcoma except clear-cell sarcomas. Most categories of sarcoma showed staining in less than 10% of tumour cells although a minority of leiomyosarcomas showed more extensive staining. Five of 7 malignant melanomas were also positive while all lymphomas and carcinomas were negative. We conclude that KP-1 positivity is not helpful in supporting the histiocytic origin of a tumour and is of limited value in the differential diagnosis of soft tissue sarcomas or their separation from other categories of malignancy.

Antigens, CD↗
PubMed1994

Pseudosarcoma of the larynx: the value of ploidy analysis.

An 82-year-old male presented with a two-month history of hoarseness. A 2 cm pedunculated lesion was removed from the base of his epiglottis. Microscopy showed a polypoid atypical spindle cell lesion. Multiple levels failed to reveal an invasive squamous cell carcinoma. On the basis of haematoxylin and eosin stained sections the main differential diagnosis was a pseudosarcoma with an overlying dysplastic squamous mucosa or infiltrating spindle cell carcinoma. Immunohistochemistry showed positive staining for vimentin but no convincing staining with antibodies to cytokeratin and EMA. Ultrastructural analysis also failed to reveal epithelial characteristics. Ploidy analysis by static cytophotometry of the spindle cell proliferation revealed an aneuploid stem line with a DNA index of 1.67. On the basis of this the process was felt unlikely to be reactive and a diagnosis of a spindle cell squamous carcinoma was made. This diagnosis was subsequently supported by a clinical recurrence of the nodule at a six-month follow-up.

Aged↗
PubMed1994

Clear cell carcinoma arising in a pleomorphic adenoma of the submandibular gland.

Clear cell carcinoma of salivary gland is a rare neoplasm. We report a third case of clear cell carcinoma arising in a pleomorphic adenoma and also in an extraparotid location. We document the immunohistochemical profile of the tumour including reactivity with a marker for the c-erbB-2 oncoprotein and suggest a myoepithelial origin for these lesions. The presence of a tetraploid stemline may account for the rapid tumour progression in this case.

Adenocarcinoma, Clear Cell↗
PubMed1994

The regional distribution of N-acetylaspartylglutamate (NAAG) and peptidase activity against NAAG in the rat nervous system.

N-Acetylaspartylglutamate (NAAG), a prevalent peptide in the vertebrate nervous system, may be hydrolyzed by extracellular peptidase activity to produce glutamate and N-acetylaspartate. Hydrolysis can be viewed as both inactivating the peptide after synaptic release and increasing synaptic levels of ambient glutamate. To test the hypothesis that NAAG and the peptidase activity that hydrolyzes it coexist as a unique, two-stage system of chemical neurotransmission, 50 discrete regions of the rat CNS were microdissected for assay. In each microregion, the concentration of NAAG was determined by radioimmunoassay and the peptidase activity was assayed using tritiated peptide as substrate. The NAAG concentration ranged from 2.4 nmol/mg of soluble protein in median eminence to 64 in thoracic spinal cord. Peptidase activity against NAAG ranged from 54 pmol of glutamate produced per milligram of membrane protein per minute in median eminence to 148 in superior colliculus. A linear relationship was observed between NAAG peptidase and NAAG concentration in 46 of the 50 areas, with a slope of 2.26 and a correlation coefficient of 0.45. These data support the hypothesis that hydrolysis of NAAG to glutamate and N-acetylaspartate is a consistent aspect of the physiology and metabolism of this peptide after synaptic release. The ratio of peptide concentration to peptidase activity was > 0.3 in the following four areas: ventrolateral medulla and reticular formation where the peptide is concentrated in axons of passage, thoracic spinal cord, where NAAG is concentrated in ascending sensory tracts as well as motoneuron cell bodies, and ventroposterior thalamic nucleus.

Animals↗
PubMed1994

Comparison of the quality of obturation following endosonic versus hand instrumentation.

This study was undertaken to compare the quality of root canal obturation following preparation by endosonic or hand instrumentation. Forty single-canal, extracted lower premolar teeth were selected. One group of 20 teeth was prepared using a standard step-back technique, the other 20 teeth were prepared with an ultrasonic machine. The groups were subdivided, with two operators preparing 10 teeth of each group. The teeth were obturated by a third operator using cold laterally condensed gutta percha. The root apices were then immersed in methylene blue dye for 48 h and the teeth sectioned longitudinally. Image analysis recorded the amount of sealer and void within the obturated canal. The linear distance of dye penetration was measured to provide an indication of apical seal. Examination of the root canal shape resulting from the different preparation techniques used was also undertaken. No significant difference was noted in the percentage of sealer and void present in the root canals obturated after endosonic or hand instrumentation. There was a slightly greater although not significant increase in the degree of linear penetration of dye in canals prepared endosonically. The endosonic technique used in this study appeared to produce a canal preparation of slightly less continuous taper than that obtained with hand preparation.

Analysis of Variance↗
PubMed1994

C-erbB-2 immunostaining: problems with interpretation.

AIMS: To assess the consistency and reproducibility of assessment of c-erbB-2 immunostaining, and to examine some of the problems relating to inter- and intraobserver variability in the documentation of positive staining; to profile the spectrum of cytoplasmic and membranous staining in a wide range of tumour types. METHODS: A total of 283 neoplasms were examined for immunohistochemical expression of the c-erbB-2 oncoprotein. Three independent observers were required to assess intensity both of membrane and cytoplasmic staining on a three point and then a four point scale. Extent of positive staining was also assessed on a two point scale. A minimum of two weeks elapsed between assessments using the differing scales. RESULTS: Positive membrane staining was documented by one or more observers in 16.6% of tumours examined. This positivity was largely restricted to bladder, renal, and breast tumours. The overall level of disagreement as to the presence or absence of membranous staining was 11.3%. Cytoplasmic staining was identified in 55.5% of tumours studied. The level of disagreement as to the presence or absence of cytoplasmic staining was 26.5%. CONCLUSIONS: Intraobserver variability was minimal, indicating that each pathologist was adhering to internal reproducible standards. Interobserver variability was greater, indicating that the interpretation of c-erbB-2 immunostaining may require set guidelines. It is suggested that assessment should be referenced to a standard positive control, that a three tier system for grading of intensity and a two tier system for grading of extent should be adopted, and that the evaluation should be agreed by at least two pathologists. The presence of cytoplasmic staining should continue to be routinely recorded until its biological role and clinical implications are fully understood.

Biomarkers, Tumor↗
PubMed1994

An update on conventional fixed bridgework. Part 4: Clinical techniques.

The first three articles of this series have emphasized the importance of careful treatment planning in conventional fixed bridgework. In this, the fourth article, attention to detail continues to be the theme. The clinical procedures for fixed bridgework (tooth preparation, temporization, impression taking and occlusal registration) will be discussed.

Crowns↗
PubMed1994

An update on conventional fixed bridges. Part 1: Patient assessment and selection.

Over the past decade there have been many developments in the field of adhesive bridgework, a conservative treatment option for the patient with intact and unrestored abutment teeth. However, many situations still exist where resin bond retained bridges are unsuitable and more conventional techniques are called for. Although adhesive bridges are potentially less damaging to tooth structure, conventional bridgework has greater implications in terms of damage to abutment teeth and surrounding tissues. It is important to execute a carefully devised treatment plan skillfully if problems are to be avoided. This paper, the first in a series of 5 articles offering biologically based, practical guidelines to the dental surgeon, discusses how patients should be selected for these procedures.

Denture, Partial↗
PubMed1994

An update on conventional fixed bridges: 2. Designing fixed bridgework.

Most patients who have lost teeth prefer a fixed prosthesis to a removable prosthesis. In this, the second article in the series, we consider the principles of design that are applicable to conventional fixed bridgework and which will enable the clinician to select the prosthesis most appropriate for a partially dentate patient.

Denture Design↗