Stability of carotenoids and alpha-tocopherol during blood collection and processing procedures.
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Adult↗
Biomedical subjects
M D Gross
Publications and source records attributed to M D Gross.
The current status of meta-iodobenzylguanidine and related agents for the diagnosis of neuro-endocrine tumors.
Metaiodobenzylguanidine (MIBG) has been in clinical use for 15 years and has been shown to have high sensitivity (about 85%) and specificity (> 95%) for the location of all types of pheochromocytomas. Similar results have been achieved with neuroblastomas. A wide range of other neuroendocrine lesions including carcinoids, medullary thyroid cancer and nonsecretory paragangliomas may also be imaged, but the lower sensitivity. The newly developed radiolabeled somatostatin analogs may have greater utility for these lesions. MIBG scintigraphy may also provide a unique in vivo probe for study of the sympathetic autonomic nervous system, particularly in the heart. Various radiolabels for MIBG and its analogs permit planar scintigraphy, SPECT, PET, intraoperative probe localization and radiopharmaceutical therapy.
3-Iodobenzylguanidine↗
The current status of radioiodinated metaiodobenzylguanidine therapy of neuro-endocrine tumors.
The avidity of many metastatic pheochromocytomas and neuroblastomas for metaiodobenzylguanidine (MIBG) observed at diagnostic scintigraphy has led to attempts to treat these lesions with large doses of MIBG. We and others have achieved therapeutic responses with 131I-MIBG (usually partial) in about a third of malignant pheochromocytomas. A small but important subgroup of advanced, poor prognosis neuroblastomas which have been resistant to all other therapies have also shown responses including occasional long-term survival (> 5 years) and apparent complete responses to 131I-MIBG. Because the physical properties of 131I are suboptimal for the delivery of therapeutic radiation to bone marrow micrometastases, a frequent problem in neuroblastoma, we have performed preliminary studies in poor prognosis Stage III and VI neuroblastoma using 125I-MIBG which has more satisfactory emissions. This has led to prolonged tumor stabilization and survival (> 19 to > 52 months) in 5 of 10 patients. MIBG radiopharmaceutical treatment of neuroendocrine tumor patients must still be considered an experimental but nevertheless promising treatment modality.
3-Iodobenzylguanidine↗
Interference by spironolactone on adrenocortical scintigraphy and other pitfalls in the location of adrenal abnormalities in primary aldosteronism.
A case of primary aldosteronism is presented in which the CT scan was initially misleading, adrenocortical scintigraphy was rendered inaccurate by pharmacological interference of spironolactone, and selective adrenal venous sampling of aldosterone was technically difficult. When dexamethasone suppression adrenocortical scintigraphy was performed with attention to technical detail and exclusion of interference by spironolactone, the causative lesion was scintigraphically demonstrated. This finding was confirmed by the results of venous sampling and the correctly located tumor removed.
Adosterol↗
Transferring provisional restorations to final master casts.
Many principles guide preparation and fitting of provisional restorations. Their importance as a diagnostic tool is considered. Aesthetic, phonetic, functional, parafunctional and dysfunctional factors after evaluation in the provisional restorations have to be transferred to the master cast to incorporate them into the final restoration. A method for transferring morphology of provisional restorations to the master cast through preparation of a wax analogue fixed partial denture is presented. This method is precise, practical, suitable for most rehabilitation cases, and not clinically time-consuming since most stages are carried out in the dental laboratory.
Dental Casting Technique↗
Locating neuroblastoma in the opsoclonus-myoclonus syndrome.
We examined the role of various medical imaging modalities, particularly metaiodobenzylguanidine (MIBG) scintigraphy in the investigation of patients presenting with the opsoclonus-myoclonus syndrome (OMS) who may harbor neuroblastomas. A retrospective analysis was therefore performed of all patients presenting with OMS in a 5 1/2 year period. Between December, 1988 and May, 1994, all 13 patients (mean age 15.2 months, range 3 days-30 months) presenting with OMS were extensively studied. A wide range of medical imaging modalities including CT, MRI and [131I] or [123I]-metaiodobenzylguanidine (MIBG) scintigraphy (total of 21 scans) were examined as a means of detecting a structural brain lesion or locating a neuroblastoma, a tumor generally found in less than half of patients with OMS. As anticipated a minority of patients (4) were eventually found to harbor neuroblastomas. In these four cases, two tumors were revealed on preoperative MIBG scintigraphy, one gave a false negative study and one tumor was not studied preoperatively. Each patient was also subjected to extensive radiological investigations in addition to MIBG scintigraphy, many of which were repetitive, redundant or had low clinical yield. The relative merits of the various procedures are compared, and an algorithm incorporating MIBG scintigraphy and limited central nervous system and abdominal anatomical modalities for the investigation of opsoclonus-myoclonus is suggested.
3-Iodobenzylguanidine↗
Plasma carotenoids as biomarkers of vegetable and fruit intake.
Higher intakes of vegetables and fruits are associated with a lower risk of certain human cancers. A biomarker of vegetable and fruit intake would be a valuable research tool. A cross-sectional study assessed the association between plasma carotenoid concentrations and intakes of vegetables and fruits. Plasma carotenoids (alpha-carotene, beta-carotene, lutein, beta-cryptoxanthin, and lycopene) were measured in 50 male and 49 female participants, aged 18-37 years, with a wide range of habitual vegetable and fruit intakes. Dietary intakes were assessed via a food frequency questionnaire. Intake of vegetables and fruits and high carotenoid foods were measured. The sum of the plasma carotenoids (excluding lycopene) was highly correlated with intake of total vegetables and fruits (r = 0.59). Of the individual plasma carotenoids, plasma alpha-carotene had the highest correlation with intakes of both total vegetables (r = 0.50) and total fruits (r = 0.58). Intakes of foods with high carotenoid contents were correlated with their corresponding plasma concentrations as follows: high beta-carotene foods (r = 0.41); high lutein foods (r = 0.46); and high lycopene foods (r = 0.11). Multiple regression analyses showed that intake of total vegetables and fruits was the most significant determinant of each plasma carotenoid except lycopene. The utility of combining the plasma carotenoids as biomarkers of vegetable and fruit intake was assessed by a stepwise regression of total vegetable and fruit intake on plasma carotenoids. Significant determinants of intake of total vegetables and fruits were alpha-carotene, beta-cryptoxanthin, lutein, and energy intake (R2 = 0.53).(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
Evidence for the formation of multiple types of acetaldehyde-haemoglobin adducts.
Acetaldehyde readily reacted with red blood cells and isolated haemoglobin to form adducts. We examined acetaldehyde-haemoglobin reaction products, isolated from red blood cells incubated with acetaldehyde (AcH), for the presence of stable peptide-specific acetaldehyde adducts. Red blood cell incubations were with 20, 50, and 200 mM acetaldehyde for 3, 24 and 48 hr. Peptide-specific [14C]acetaldehyde modifications of Hb from each incubation were identified by tryptic peptide mapping procedures. Nine peptides had modifications and six were found in incubations with 20 mM acetaldehyde. Two of the peptides were acetaldehyde modifications of the Hb alpha- and beta-chain N-termini. Stability studies indicated that the remaining seven [14C]AcH-modified peptides did not result, as can occur under certain conditions, from the transfer of AcH on the N-termini of Hb to N-termini formed after trypsin digestion. An analysis of the relative amounts of [14C]AcH-peptide adducts indicated that at least two of the seven peptides had reactivities for AcH different than the N-termini of Hb; that is, at least two modified peptides differ from imidazolidine-type adducts formed on the N-termini. The presence of multiple modifications with different sensitivities for AcH adduct formation may be useful in developing markers of alcohol consumption.
Acetaldehyde↗
Scintigraphic evaluation of clinically silent adrenal masses.
UNLABELLED: We studied 229 patients with abnormal adrenal anatomy depicted by CT who were without biochemical evidence of endocrine dysfunction using the presence of 131I-6 beta-iodomethyl-nor-cholesterol (NP-59) adrenal gland uptake as an index of differential adrenal function in the evaluation of the clinically "silent" adrenal mass lesion. METHODS: NP-59 (1 mCi) was injected intravenously with posterior and lateral abdominal images obtained 5-7 days postinjection. RESULTS: One-hundred and fifty-nine of 185 patients with unilateral adrenal enlargement on CT had scintigraphic evidence that the mass represented a functioning (NP-59 avid) but not hypersecretory, (biochemically normal) adrenal cortical adenoma (concordant imaging pattern). Forty-one of 44 patients with intra-adrenal neoplasms were depicted on scintigraphy as decreased or absent NP-59 accumulation on the side of the adrenal mass (discordant imaging pattern). In this study, sensitivity was 71% (41 of 58 patients; 95% confidence interval (CI), 58% to 88%); specificity was 100% (171 of 171 patients; 95% CI, 95% to 100%) and accuracy was 93% (212 of 229 patients; 95% CI, 88% to 96%). CONCLUSIONS: These data confirm our earlier observations that the functional information depicted by scintigraphy complements the morphological evaluation by CT and in the absence of hormonal dysfunction, the presence of concordant CT and 131I-NP-59 scans are characteristic of functioning, but not hypersecretory, benign adrenocortical adenomas. Conversely, discordant CT and 131I-NP-59 scans are suggestive of nonfunctioning, space-occupying, adrenal lesions.
Adenoma↗
Technetium-99m-red blood cell scintigraphy in the localization of nonenteric hemorrhage.
Rapid detection and localization of the bleeding site(s) are important factors in successful management of actively bleeding patients. Technetium-99m-red blood cell imaging is a sensitive, noninvasive modality commonly used for localization of gastrointestinal bleeding. Outside the gastrointestinal tract, experience with this technique has been limited. In this report, we present three cases of nonenteric bleeding successfully located using 99mTc red blood cells. The current literature regarding the scintigraphic localization of nonenteric bleeding is reviewed and discussed.
Aged↗
Quantification of aspiration: methodological and clinical perspectives.
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Deglutition↗
A functional and degenerate pair of EF hands contains the very high affinity calcium-binding site of calbindin-D28K.
Calbindin-D28K, a member of the troponin C superfamily of calcium-binding proteins, had six putative EF hand domains containing one very high affinity and two to three lower affinity calcium-binding sites. The location and binding activity of the calcium-binding sites were examined with a recombinant calbindin-D28K protein. This protein (Calb I-II) only contained EF hand domains 1 and 2 of calbindin-D28K. Binding of calcium and calcium analogs, the lanthanides, by the recombinant protein was determined in fluorescence emission experiments. Calb I-II bound 1 mol of terbium/mol of protein. Terbium was displaced from Calb I-II by other lanthanides and calcium. Fluorescence from terbium was not quenched by holmium. These results and Hill plots of calcium binding activity, determined from intrinsic protein fluorescence measurements, indicated the presence of a single high affinity calcium-binding site on Calb I-II. The properties of the binding site indicated that the very high affinity site of calbindin-D28K was located in EF hand domains 1 and 2 of the protein. In addition, these findings indicated the NH2-terminal pair of EF hands in calbindin-D28K did not depend on interactions with other domains in the protein for high affinity calcium binding activity. The results suggested at least one calcium-binding domain of calbindin-D28K can exist as an independent EF hand pair.
Amino Acid Sequence↗
Investigation of the effects of a variable lateral guidance incline on the pantronic registration of mandibular border movement: Part II.
This study was designed to test the hypothesis that changes in lateral guidance inclination could affect the condylar registrations in the recordings of an electronic pantography. In seven healthy subjects, pantronic registrations of immediate side shift, progressive side shift, and orbiting and protrusive condylar paths were recorded with lateral anterior guidance inclinations of 0, 20, 30, 45, and 60 degrees from the same pin height. Analysis of variance with repeated measures showed a significant decrease in the immediate side shift (p 0.016) and the progressive side shift (p 0.051) as the lateral guidance angle increased and no significant effect on the orbiting registrations. These observations, together with those from other studies, suggest that the concept of fabricating the working-side tooth guidance exactly according to instrument condylar settings (which themselves may be subject to a variable recording lateral anterior guidance) appears untenable and demands further study.
Adult↗
Impaired left ventricular contractile function in patients with long-term mitral regurgitation and normal ejection fraction.
OBJECTIVES: We tested the hypotheses that left ventricular chamber elastance would detect impaired contractile function in patients with long-term mitral regurgitation and a normal ejection fraction and that these patients would have unique temporal left ventricular size and ejection fraction responses to mitral valve surgery. BACKGROUND: Although it has been suggested that left ventricular contractile function may begin deteriorating in patients with long-term mitral regurgitation whereas ejection fraction remains normal, no data exist in humans. METHODS: We studied 11 control patients and 28 patients with long-term mitral regurgitation using micromanometer-measured pressures, biplane contrast cineventriculography and radionuclide angiography under control conditions and with alterations in load during right atrial pacing to calculate left ventricular chamber elastance and myocardial stiffness. RESULTS: The patients with mitral regurgitation were classified into subgroups: Group I, normal contractile function; Group II, impaired contractile function (reduced Emax) but normal ejection fraction, and Group III, impaired contractile function (reduced Emax) with reduced systolic myocardial stiffness. Twenty-two of the patients with mitral regurgitation underwent mitral valve surgery. In Group I, comparable decreases in left ventricular volume indexes (p < 0.01 and p = 0.05, respectively) were associated with no change in ejection fraction at 3 months and 1 year. In contrast, in Group II, reductions in volume indexes (p < 0.0001 and p < 0.001) were associated with a short-term decrease in ejection fraction (p < 0.001) that recovered at 1 year (p < 0.01 vs. short-term). Finally, in Group III, variable responses in volume indexes were associated with a consistent decrease in ejection fraction at 3 months and 1 year. CONCLUSIONS: An analysis of left ventricular chamber elastance provides data to support the concepts that 1) contractile function is impaired in some patients with long-term mitral regurgitation and a normal ejection fraction, 2) impaired contractile function may not be irreversible in all of these patients, and 3) an earlier consideration of mitral valve surgery may be warranted to preserve contractile function in these patients.
Adult↗
Extensive salivary contamination due to concurrent use of chewing tobacco during I-131 radioablative therapy.
Although multiple authors have reported on various causes of external I-131 contamination after administration of radioiodine, to the authors' knowledge there have been no reported cases of external contamination from salivary secretions due to expectoration of chewing tobacco. A case of extensive I-131 contamination of a hospital room, furniture, and plumbing due to indiscriminate use of chewing tobacco during an inpatient I-131 radioablative therapy is presented.
Aged↗
Acute effects of alcohol administration on regional cerebral blood flow: the role of acetate.
The effect of alcohol intoxication on regional cerebral blood flow (rCBF) is unclear. The few published studies provide a mixed picture of alcohol effects, suggesting that blood flow increases at low doses and decreases at higher doses of alcohol. Using the cerebral blood flow agent 99mtechnetium hexamethyl-propylene-amine-oxime (HMPAO) and image reconstruction with single photon emission computed tomography (SPECT), we evaluated the effect of an oral dose of ethanol (0.6 g/kg) on rCBF in two age-stratified groups of healthy, nonalcoholic men (12 age 22-37 and 12 age 63-77). Intoxication was associated with a significant 4% increase in global cortical CBF (t = 2.54, p = 0.02). Changes in HMPAO uptake were negatively correlated to ethanol levels in the entire group (r = -0.47, p = 0.04). This relationship was seen in the older subgroup (r = -0.70, p = 0.05), but not in the younger group (r = -0.34, p = 0.26). In contrast, the younger group showed a significant positive correlation between rCBF and increases in acetate levels (r = 0.71, p < 0.01), which was not seen in the older group (r = -0.02, p = 0.96). These findings suggest that both acetate and alcohol contribute to the changes in CBF seen in the intoxication syndrome and that their relative influence is age-dependent.
Acetates↗
Clinical review 50: Clinically silent adrenal masses.
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Adrenal Gland Diseases↗
L-thyroxine overdose: a case of marked, severe, prolonged, excess ingestion and review of the literature.
A case of a man with thyroid cancer who ingested between 0.9 and 3.3 mg l-thyroxine per day for over 10 years (the highest dose for 3 years) is reported. This had been prescribed for suppression of TSH for a well differentiated thyroid cancer. He was essentially asymptomatic and suffered no apparent ill effects from this prolonged and markedly excessive dosage of l-thyroxine. The literature lists a wide range of ill effects from both chronic and acute thyroid hormone overdosage but also records many examples of tolerance to excessive levels of exogenous thyroid hormone. The various circumstances leading to thyroid hormone overdose and potential ill-effects are reviewed.
Adult↗