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S J Graham

Publications and source records attributed to S J Graham.

At least 37 records · Page 2Linked to original sources
PubMed1998

Time and temperature dependence of MR parameters during thermal coagulation of ex vivo rabbit muscle.

Detailed measurements of the T1-weighted, T2-weighted, and MT-weighted signal were performed for ex vivo muscle samples heated to various temperatures for different times. Consistent, monotonic increases in signal intensity were observed with progressive thermal coagulation, corresponding to an increase in T2 relaxation time and an increase in MT-weighted signal for temperatures above 60 degrees C. The relationship for T1 relaxation was more complex, showing a decrease in T1 relaxation from 40 to 60 degrees C and an increase above 60 degrees C. These techniques provide a more direct measure of tissue thermal coagulation than that provided by MR thermometry and suggest MR imaging strategies for the optimization and monitoring of thermal coagulation therapy protocols that create thermal damage in target tissues.

Animals↗
PubMed1997

A flexible magnetization transfer line shape derived from tissue experimental data.

To summarize and compare magnetization transfer data from biological tissues, a method was developed to extract the average absorption lineshape of the semi-solid pool directly from magnetization transfer experimental data along with the four other parameters that characterize the two-pool model of exchange. Magnetization transfer data for several biological tissues were analyzed using this method and the resulting "flexible" lineshapes were compared with super-Lorentzian and "Kubo-Tomita" lineshapes. The use of flexible lineshapes noticeably improves the fit of the two-pool model to the data. The derived flexible lineshapes of all the tissues analyzed are physically realistic and show remarkably consistent behavior.

Animals↗
PubMed1997

Magnetic resonance properties of ex vivo breast tissue at 1.5 T.

The magnetic resonance absorption spectrum, T1 and T2 relaxation time distributions, and magnetization transfer properties of ex vivo breast tissue have been characterized at 1.5 T and 37 degrees C. The fraction of fibroglandular tissue within individual tissue samples (n = 31) was inferred from the tissue volumetric water content obtained by integration of resolvable broad-line fat and water resonances. The spectroscopically estimated water content was strongly correlated with that extracted enzymatically (Pearson correlation coefficient 0.98, P < < 0.01), which enabled the assignment of principal relaxation components for fibroglandular tissue (T2=0.04+/-0.01, T1=1.33+/-0.24 s), and for adipose tissue (T2=0.13+/-0.01, T1=0.23+/-0.01 s, and T2=0.38+/-0.03, T1=0.62+/-0.16 s). Th e relaxation components for fibroglandular tissue exhibited strong magnetization transfer, whereas those for adipose tissue showed little magnetization transfer effect. These results ultimately have applicability to the optimization of clinical magnetic resonance imaging and research investigations of the breast.

Breast↗
PubMed1997

Metered dose inhalers III: Metaproterenol sulphate; particle size distribution and dose uniformity.

Three American products and one Canadian product were examined for content uniformity and particle size distribution. The results showed that not all products performed equally well. Some of the products exhibited high sprays early in the canister lifetime and all products demonstrated loss of prime. The particle size distributions were determined using the Andersen cascade impactor (USP Induction Port) and the fine particle fraction was determined using the twin impinger. The results showed that three of the four products had similar particle size distribution profiles. Both the Andersen cascade impactor and the twin impinger yielded the same trends in the amount of drug substance delivered to the fine particle fraction.

Bronchodilator Agents↗
PubMed1996

Criteria for analysis of multicomponent tissue T2 relaxation data.

Monte Carlo simulations were performed to determine whether the multicomponent T2 distribution of tissue can be estimated accurately from T2 decay data acquired in vivo. Simulated data were generated for white matter, fast twitch muscle, and breast tissue. The signal-to-noise ratio, number of data samples, and minimum echo time were varied from the experimental conditions currently achievable with MRI to those achievable for in vitro experiments. Data were fitted by a distribution of T2 values using the T2NNLS algorithm, and statistics characterizing the estimated T2 components were determined. Current MRI techniques were found to provide conditions insufficient for accurate multicomponent T2 analysis on a pixel-by-pixel basis. However, volume localization methods that measure T2 decay from a large volume of interest have potential for this analysis. These results illustrate a general framework for development of new techniques to measure T2 decay accurately in vivo.

Brain Chemistry↗
PubMed1996

MR measurement of relative water content and multicomponent T2 relaxation in human breast.

MR techniques providing accurate measurement of relative volumetric water content and multicomponent T2 relaxation times from a large volume of interest, have been implemented for characterization of breast tissue in vivo. In a sequence of 20-s breath-holds, data are obtained from much of the breast volume while suppressing signal from the chest wall and torso. Relative water content of each breast is calculated from one-dimensional fat and water profiles obtained using a hybrid two-point Dixon method (TE/TR = 17/5000 ms). Multicomponent T2 relaxation measurements are calculated from T2 decay curves obtained using a CPMG train of rectangular pulses (TE/TR = 8/5000 ms, 140 echoes) preceded by saturation pulses to localize longitudinal magnetization spatially. These techniques, validated in phantoms and human volunteers, are suitable for quantitative study of breast tissue in vivo, and in particular to investigate the potential role of MR for assessment of breast cancer risk.

Body Water↗
PubMed1996

Metered-dose inhalers, I: Drug content and particle size distribution of beclomethasone dipropionate.

Four commercially available beclomethasone metered dose inhalers were analyzed for both spray content uniformity and particle size. The drug contents of primed and unprimed sprays collected at the beginning of the lifetime of the canister were not significantly different from those collected throughout the experiment. Particle size analysis of the four products using the Andersen Cascade Impactor Mark II showed that the distribution profiles were not identical. An existing HPLC method was modified to quantitate single sprays for content uniformity and to measure the amount on an impactor stage for particle sizing.

Administration, Inhalation↗
PubMed1996

Quantitative correlation of breast tissue parameters using magnetic resonance and X-ray mammography.

Previous investigators have shown that there is a strong association between the fraction of fibroglandular tissue within the breast as determined by X-ray mammography (per cent density) and breast cancer risk. In this study, the quantitative correlation between per cent density and two objective magnetic resonance (MR) parameters of breast tissue, relative water content and mean T2 relaxation time, as investigated for 42 asymptomatic subjects. Using newly developed, rapid techniques MR measurements were performed on a volume-of-interest incorporating equal, representative portions of both breasts. X-ray mammograms of each subject were digitised and analysed semiautomatically to determine per cent density. Relative water content showed a strong positive correlation with per cent density (Pearson correlation coefficient rp = 0.79, P < 0.0001) and mean T2 value showed a strong negative correlation with per cent density (rp = -0.61, P < 0.0001). The MR and X-ray parameters were also associated with sociodemographic and anthropometric risk factors for breast cancer (P < 0.05). The potential use of MR parameters to assess risk of breast cancer and to provide a frequent, non-hazardous monitor of breast parenchyma is discussed.

Adipose Tissue↗
PubMed1993

Prognostic implications of a bone marrow histopathologic classification system in mycosis fungoides and the Sézary syndrome.

BACKGROUND: The authors devised a histopathologic classification system for interpreting bone marrow biopsy materials in patients with mycosis fungoides and the Sézary syndrome and correlated histopathologic findings with clinical stage and outcome. METHODS: Bone marrow specimens from 90 consecutively staged patients were examined for lymphoid infiltrates, benign or cytologically atypical lymphoid aggregates, and large or cytologically transformed cells. RESULTS: Thirty-seven (41%) marrows were involved, two with diffuse lymphomatous infiltrates and 35 with lymphoid aggregates. Twelve of the 35 had lymphoid aggregates consisting of cytologically normal-appearing lymphocytes, and 23 had aggregates composed of cytologically atypical lymphocytes. Eleven patients had greater than 5% large cytologically transformed cells. Patients with infiltrative disease or cytologically atypical aggregates had an inferior survival compared with those with cytologically normal lymphocytes (P2 = 0.0042), and patients with aggregates consisting of cytologically normal lymphocytes had a survival comparable with that of patients with uninvolved marrows (P2 = 0.33). Whereas most patients with cytologically atypical marrows had advanced skin and lymph node involvement, 28% had early skin stage. Bone marrow eosinophilia was noticed in 38% of patients and was not consistently associated with peripheral blood eosinophilia or clinical stage. CONCLUSIONS: These results suggest that patients with cytologically atypical lymphoid aggregates or diffuse lymphomatous infiltration of the marrow have an inferior survival regardless of clinical stage, whereas those with lymphoid aggregates consisting of cytologically normal-appearing lymphocytes have a survival indistinguishable from that of patients without lymphoid aggregates.

Adult↗
PubMed1992

Whole-body pathologic analysis of a patient with Thorotrast-induced myelodysplasia.

An autopsy was performed on a 72-y-old Caucasian female who had received a carotid artery injection of thorium dioxide in 1953. The body was dissected in such a manner as to provide for radiobiological evaluation as well as to determine histologically the distribution of Thorotrast in the tissues and its complications. Thorotrast was identified within the liver, spleen, lymph nodes, bone marrow, and surrounding the right carotid artery (the injection site). The cause of death was gastric hemorrhage complicating pancytopenia secondary to refractory anemia with excess of blasts (myelodysplastic syndrome).

Aged↗
PubMed1992

Inferior punctal occlusion with removable silicone punctal plugs in the treatment of dry-eye related contact lens discomfort.

Thirty subjects complaining of a decrease in soft contact lens wearing time secondary to dry eye discomfort were selected for our study. All subjects were between the ages of 25 and 40 and selected on the basis of subjective dry eye complaints alone. Five of these subjects had punctum that were too small to facilitate plug placement and were therefore eliminated from further study. Removable silicone punctal plugs were monocularly placed in the lower puncta of the remaining 25 subjects. In an attempt to minimize the placebo effect, both puncta were manipulated equally prior to plug insertion and the patient was not told which eye had been treated. Three weeks following plug placement, blind data assessment showed that 18 of the 25 subjects reported, on average, a 34.6 percent increase in comfortable contact lens wearing time in the treated eye. Three subjects reported no subjective increase in comfortable wearing time and four subjects were unable to tolerate the punctal plugs for more than a week due to plug-related discomfort. Problematic epiphora was not reported in any of the treated eyes. Reversible inferior punctal occlusion, when tolerated, can significantly increase comfortable contact lens wearing time while still allowing enough drainage from the upper puncta to prevent epiphora.

Adult↗
PubMed1991

Sublingual apomorphine solution in Parkinson's disease.

OBJECTIVE: To compare the effects of single doses of oral levodopa, subcutaneous apomorphine and sublingual apomorphine. DESIGN: Single-blind placebo-controlled comparative study. SETTING: Subjects were admitted as day patients to the neurology ward. PATIENTS: Five patients with idiopathic Parkinson's disease and "end of dose deterioration" entered and completed the study. INTERVENTIONS: Patients were given domperidone (20 mg by mouth three times a day) to prevent nausea and apomorphine (1-3 mg by subcutaneous injection), apomorphine in glycerol (10-30 mg sublingually) or their usual levodopa regimen. MAIN OUTCOME MEASURES: Efficacy, time to onset of effect and duration of effect of oral levodopa, subcutaneous apomorphine and sublingual apomorphine. Tremor amplitude and timed pegboard and gait tasks were used as objective indices of clinical state. RESULTS: Maximal efficacy of the three treatments was comparable (P = 0.28-0.99). Mean latency to onset of effect of both formulations of apomorphine was less than that of levodopa (P = 0.022-0.048) but so was the duration of effect (P = 0.044-0.049). CONCLUSIONS: Sublingual apomorphine may be a convenient means of rapidly terminating "off" periods associated with long term levodopa therapy.

Administration, Oral↗
PubMed1991

Malignant cyst of the lateral aspect of the neck: branchial cleft carcinoma or metastasis?

A 58-year-old man had a left jugulodigastric mass, which was found to be cystic by computed tomography, and no evidence of other lesions. Grossly and histologically, the surgical specimen consisted of a thin-walled, fluid-filled cyst lined by squamous epithelium that varied in appearance from benign to invasive squamous cell carcinoma. The findings supported a differential diagnosis of branchial cleft carcinoma (BCCA) versus cystic growth of a lymph node metastasis from an occult malignancy. On this basis, guided biopsies of the upper aerodigestive tract were performed, with strong suspicion of a tonsillar bed lesion. Microscopic examination revealed the primary tumor within tissue excised from the left tonsillar fossa. Comparison of the current case with cases of BCCA and cystic tonsillar metastases from the literature illustrated the potential pitfalls in rendering a diagnosis of BCCA. Recognition of this lesion as a distinctive clinical variant of oropharyngeal carcinoma is warranted.

Branchioma↗
PubMed1991

High-performance liquid chromatographic method for the assay of verapamil hydrochloride and related compounds in raw material.

A modification of the USP HPLC method [ United States Pharmacopeia XXII, pp. 1444-1446] for the assay of the purity of verapamil hydrochloride has been evaluated for the determination of the drug content and related compounds in drug raw material. The method enables the resolution of 16 related compounds from the parent drug and, in most cases, from each other. The minimum quantifiable amount for most related compounds is less than 0.05%. Six drug raw material samples are analysed and the total impurities found to be 0.3% or less. All drug assay values were within the USP recommended limits of 99.0-100.5%.

Chromatography, High Pressure Liquid↗
PubMed1990

Burkitt's lymphoma: a pericardial presentation.

Described herein is a case of childhood Burkitt's lymphoma initially presenting as a pericardial effusion. A cytological diagnosis was made from a Wright's-Giemsa stained cytospin preparation. Supporting diagnostic evidence was provided by immunological surface marker analysis and electron microscopy. To our knowledge, Burkitt's lymphoma has not hitherto been diagnosed initially from the morphology of cells in pericardial fluid.

Biopsy, Needle↗