Search PubMed⌕ Search

Biomedical subjects

D M Lyster

Publications and source records attributed to D M Lyster.

At least 37 records · Page 2Linked to original sources
PubMed1984

Gamma scintigraphy using Tc-99m labeled antibody to human chorionic gonadotropin.

A case report is presented describing a 27-year-old woman with invasive trophoblastic hydatidiform mole metastatic to the lung. Gamma scintiscanning, using a polyclonal and monoclonal antibody specific to human chorionic gonadotropin, hCG, and labeled with Tc-99m, is described. The area of the primary lesion in the uterus was demonstrated with both antibodies tested without computer subtraction techniques; metastatic deposits in the lung were detected only with the aid of blood pool subtraction techniques.

Adult↗
PubMed1983

Potential use of radiolabelled porphyrins for tumor scanning.

Fe-TMPI, Fe-TCP and protohemins showed high initial uptake using tissue culture techniques with mouse tumor cells (P815). However, the tumor uptake in the in vivo model was poor. Of the radionuclides investigated, iron labelled to TMPI demonstrated the best uptake by tumor in vitro. As has been previously demonstrated, the unnatural meso-arylporphyrin derivatives showed better uptake than did naturally occurring porphyrins and their derivatives.

Animals↗
PubMed1982

Leaking Glenn anastomosis demonstrated by first pass radionuclide angiography.

First pass radionuclide angiography was used to demonstrate a leaking Glenn anastomosis at the superior vena cava--right atrial junction as well as tricuspid atresia and a ligated persistent left superior vena cava. First pass radionuclide angiography may demonstrate anatomic configurations not obvious at cardiac catheterization and can be useful for adults with complicated congenital heart disease, particularly when biplane or multiple view angiography is not possible. Lung perfusion imaging can lead to an incorrect diagnosis of pulmonary embolism if the presence of a Glenn anastomosis in not known.

Adult↗
PubMed1980

Prevention of aspirin-induced faecal blood loss by prostaglandin E2.

Prostaglandins have been shown in animal laboratory studies to be capable of protecting the gastrointestinal tract against injury by exogenous agents. This study was conducted to determine if prostaglandin E2 (PGE2), which is native to the human gastric mucosa, could influence the increase in faecal blood loss associated with the ingestion of aspirin (ASA). A randomised double-blind study was performed on 27 healthy men. Faecal blood loss was measured by the 51Cr labelled red cell technique. ASA (600 mg four times daily) caused a significant increase in faecal blood loss. PGE2 (1 mg four times daily) had no effect on faecal blood loss when administered alone. When given in addition to ASA it resulted in a faecal blood loss not significantly different from control. No significant alteration in intestinal transit occurred. It is concluded that PGE2 protects man from the gastrointestinal injury associated with ASA.

Adult↗
PubMed1977

Evaluation of formamidine sulfinic acid and other reducing agents for use in the preparation of Tc-99m labeled radiopharmaceuticals.

Various reducing agents have been evaluated for their potential usefulness in the preparation of 99mTc labeled radiopharmaceuticals for use in nuclear medicine. Adequate labeling of various radiopharmaceuticals was accomplished using formamidine sulfinic acid. Nitrogen-purging of solutions is not required, which is an advantage for in-house preparation. Tagging requires heating, however, so heat-labile material cannot be used. Various compounds that could not be labeled when stannous chloride was used, could be tagged with 99mTc when formanidine sulfinic acid was used as the reducing agent.

Amidines↗
PubMed1977

An evaluation of radiocolloid sizing techniques.

Techniques for sizing radiocolloids are reviewed. The small size range (1-100 nm) of many radiocolloids and their polydispersity limit the choice of the technique used. To compare several techniques directly, the particle size of Technetium-99m sulfide colloid was studied using Nuclepore filtration, ultracentrifugation and electron microscopy. The last of these was adopted as the method of choice. Using this technique, the particle size and shape of colloids below 100 nm can be accurately determined. Technetium-99m antimony sulfide colloid and indium-113m hydroxide were then examined by electron microscopy, and the chemical nature of the particles was determined by x-ray fluorescence analysis. Results resolved the size discrepancies reported in the literature and demonstrated the importance of identifying the chemical nature of the particles under examination.

Colloids↗
PubMed1976

99mTc-bioquin-7CA, a potential new hepatobiliary scanning agent.

The complex 99mTc-Sn-8-hydroxyquinoline-7-carboxylate (99mTc-bioquin-7CA) was investigated in animals as a potential hepatobiliary scanning agent. Following intravenous injection, the complex was found to localize in the liver rapidly and in the gallbladder in 5--15 min; after 15 min it was excreted into the biliary tract with a high degree of specificity. Urinary excretion was negligible, reducing scan interference from the kidneys. Distribution studies in mice compared well withe localization of activity observed in rabbit scans. Preparation of the complex was rapid and simple; stannous ion was used as the reducing agent.

Biliary Tract Diseases↗
PubMed1975

Analbuminemia in a neonate.

A small-for-gestational-age infant, found to have analbuminemia in the neonatal period, is reported and the twelve cases recorded in the world literature are reviewed. Patients lacking this serum protein are essentially asymptomatic, apart from minimal ankle edema and ease of fatigue. Apparent compensatory mechanisms which come into play when serum albumin is low include prolonged half-life of albumin and transferrin, an increase in serum globulins, beta lipoprotein, and glycoproteins, arterial hypotension with reduced capillary hydrostatic pressure, and the ability to respond with rapid sodium and chloride diuresis in response to small volume changes. Examination of plasma amino acids, an investigation not previously reported, revealed an extremely low plasma tryptophan level, a finding which may be important in view of the role of tryptophan in albumin synthesis.

Blood Chemical Analysis↗
PubMedDate not supplied

Animal model for investigation of spinal cord injury caused by aortic cross-clamping.

The objective of this experimental protocol was to design a large animal model that could simulate the ischemic condition caused by aortic cross-clamping during the operation for intrathoracic and thoraco-abdominal aneurysm. Domestic swine weighing 25 to 30 kg were used for this model. The thoracic cavity was opened through the fourth intercostal space. Cross-clamp was applied below the left subclavian artery. Duration of cross-clamp was 30 min and the reperfusion period was 24 h. Methods of assessment included Tarlov's criteria, histology transmission electron microscopy, and spinal cord perfusion with microspheres. This model is reproducible. The results of experimental protocols completed using this model are referenced. This article discusses the details of the experimental protocol with steps toward reproduction of the model and rationalization. This animal model can be used for the evaluation of the pathophysiology of spinal cord injury and sensory- and motor-evoked potentials, and most importantly it can also be used for the examination of pharmacological interventions for prevention and treatment of ischemia reperfusion injury caused by aortic cross-clamping.

Animals↗
PubMedDate not supplied

Interstitial lymphoscintigraphy for lymphatic mapping in surgical practice and research.

Lymphoscintigraphy is a nuclear medicine technique that gives morphologic and functional information about the lymphatic system. The size of radiopharmaceutical used is a critical factor for it to have acceptable characteristics of uptake by the lymphatics and migration to lymph nodes. A small particle (10-100 nm) with opsonins or a unique surface is required for uptake by lymph-node macrophages. It can be prepared for application with a simple filtering process producing a predictable size distribution and number of particles for the scan. The radiation dose is safe for the patient and staff. Technetium-99m sulfur colloid is readily available and approved for use. The injection can be performed by anyone with certification in handling radiopharmaceuticals. Imaging is done with standard gamma cameras available in any nuclear medicine department. The addition of the hand-held gamma probe adds a new dimension to application of the technique of lymphatic mapping and identification of areas that retain radiopharmaceuticals. Its use is simple and reproducible. The application of lymphoscintigraphy and gamma-probe localization techniques in clinical medicine is best exemplified with the now commonly used sentinel node approach to staging and treating intermediate-thickness malignant melanoma. A number of other malignant diseases such as breast cancer may have their treatments altered with these techniques as well. As a research and diagnostic tool, the creative application of interstitial lymphoscintigraphy can give important qualitative information regarding the morphology and physiology of the lymphatic system. The development of these techniques for surgical research and practice is reviewed.

Breast Neoplasms↗
PubMedDate not supplied

Assessment of myocardial metabolic state after hypothermic heart preservation for transplantation utilizing radioiodinated free fatty acid imaging.

Myocardial turnover of 15-p-iodo(123I)-phenylpentadecanoic acid (123I-IPPA) was assessed in 14 swine experiments before and after orthotopic heart transplantation. Two preservation techniques were used: simple hypothermic storage (group 1; n = 7) and a perfusion technique (group 2; n = 7) with pressure maintained at 28 cm H2O (20 mm Hg) and a myocardial temperature of 8 to 10 degrees C. Hearts in both groups were initially perfused with hypothermic isosmolar potassium cardioplegic solution to acquire immediate diastolic arrest. The perfusate in group 2 was an extracellular formulation supplemented with glucose, mannitol, insulin, and oxygen. The ischemic interval for both groups was 6 hours including orthoptic transplantation. Pretransplant and posttransplant planar gamma imaging was performed using 3 to 5 mCi 123I-IPPA. Fatty acid turnover was assessed using time-activity curves analyzed by monoexponential least squares curve fitting generating t1/2 (half-lives in minutes). Increases in t1/2 were observed in hearts of both groups after transplantation, that is, lateral (290% +/- 72% and 104% +/- 49% increase, p = 0.03), septal (140% +/- 34% and 39% +/- 29% increase, p = 0.02), and apical (273% +/- 111% and 133% +/- 44% increase, p = 0.06) walls within groups 1 and 2, respectively. We conclude that 123I-IPPA turnover is useful in assessing the immediate metabolic state of posttransplant myocardium. It can also be concluded that preservation techniques based on continuous hypothermic perfusion are better able to maintain normal metabolic substrate utilization immediately after transplantation than are simple hypothermic storage techniques.

Animals↗