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Biomedical subjects

R H Reid

Publications and source records attributed to R H Reid.

At least 37 records · Page 2Linked to original sources
PubMed1990

Radiopharmaceutical factors in the variable quality of [99mTc]HM-PAO images of the brain.

Variability in the quality of [99mTc]HM-PAO images of the brain has been attributed to differences between kits and the addition of excessive amounts of pertechnetate to the kits. A retrospective study showed no significant differences between batches of kits with respect to radiochemical purity (RCP) or image quality. Up to 3000 MBq (81 mCi) pertechnetate could be added to the kit without adversely affecting RCP or image quality. It was shown that image quality was directly affected by RCP at time of injection and dropped sharply when RCP fell below 85%. Interstitial injection and mixing with blood prior to injection also resulted in poor image quality. Pretreatment with perchlorate reduced uptake of activity in the parotid glands; this improved image quality and reduced the influence of RCP.

Brain↗
PubMed1989

Computer simulations of a tumor surface octapeptide epitope.

Molecular dynamics using CHARMM and GEMM programs with the Star Technologies ST 100 array processor functioning at the speed of super computers was used as a searching algorithm for conformational exploration of the octapeptide Gly-Asn-Thr-Ile-Val-Ala-Glu. This poorly soluble octapeptide is the N-terminal epitope of an 11 KD glycoprotein antigen residing on human ductal carcinoma (breast) cells. Very long (nanoseconds) simulations were required. Both an alpha-helix and the N-acetyl-N1-methylamide derived minimized starting structures gave the same lowest potential energy conformation with simulations at 600 K. The same conformation was found only when using the latter starting conformation with simulations at 300 K. The lowest potential energy conformation was stabilized by 4 hydrophobic contacts and 13 H bonds completing one turn of a left-handed helix.

Algorithms↗
PubMed1989

Clinical use of technetium-99m HM-PAO for determination of brain death.

We report our clinical experience with the use of [99mTc]hexamethyl propyleneamine oxime (HM-PAO) in establishing a diagnosis of brain death in 11 patients following trauma to the head and four patients who suffered atraumatic injuries. In 9/15 studies there was no intracranial flow present and brain death was then confirmed by standard criteria. Of the remaining 6/15 studies which showed evidence of cerebral perfusion, 3/6 patients underwent a subsequent HM-PAO study which showed cessation of perfusion. One additional patient died of pneumonia and two patients survived. Thus, in all cases where there was no flow present the diagnosis of brain death was later confirmed whereas three patients clinically thought to be brain dead showed significant perfusion and survived the cerebral trauma. HM-PAO may be useful in determination of brain death because it provides unequivocal results, can be performed by planar imaging at the bedside, and does not require withdrawal of medical therapy, thus allowing a diagnosis to be established more rapidly.

Brain↗
PubMed1988

Technetium-99m HM-PAO stereoisomers: differences in interaction with glutathione.

[99mTc]HM-PAO exists as two stereoisomers, d,1 and meso, only one of which is retained in the brain. It has been suggested recently that the biodistribution of [99mTc]d,1-HM-PAO can be explained by its interaction with glutathione (GSH) in the tissues. We studied the interactions of the d,1 and meso isomers with GSH in vitro by measuring the partitioning of activity between ethyl acetate and aqueous GSH solutions at various concentrations. Partitioning of both isomers demonstrated a sigmoidal relationship with GSH concentration, but the d,1 isomer showed eightfold greater reactivity than the meso isomer. In a separate experiment, the d,1 isomer showed a sevenfold greater interaction rate with GSH than the meso isomer. These results suggest that the stereoisomers of [99mTC]HM-PAO show differences in their interaction rate with GSH which may explain their different retention in the brain.

Glutathione↗
PubMed1986

Recurrent gastrointestinal bleeding from jejunal duplication.

A 26-year-old man presented on several occasions over a four-year period because of lower gastrointestinal bleeding. The cause of this eluded correct diagnosis and curative therapy until liver-spleen imaging and a tagged RBC bleeding study were performed at the time of active bleeding and compared.

Adult↗
PubMed1985

Staphylococcal protein A bound to Sepharose 4B is mitogenic for T cells but not B cells from rabbit tissues.

The mitogenicity of protein A from Staphylococcus aureus bound to Sepharose 4B (SpA-S) was tested against mononuclear cells from normal rabbit spleens and Peyer's patches after using Sephadex G-10 adherence chromatography to deplete macrophages and Sephadex G-200 anti-rabbit F(ab')2 immunoabsorbent columns to obtain B-enriched lymphocytes. Macrophage-depleted unseparated lymphocytes and the B-cell-depleted (T-cell-enriched) fractions from both tissues consistently showed good mitogenic responses to SpA-S. In contrast, the B-cell-enriched populations from either tissue did not respond to SpA-S. Supplementary experiments employing glass adherence and T-cell autorosetting did not support the possibility that the more efficient immunoabsorbent method of B-cell isolation had in some way caused the unresponsiveness to SpA-S. These results indicate that SpA-S is mitogenic for rabbit tissue T cells but will not serve as a T-independent mitogen for rabbit tissue B cells.

Animals↗
PubMed1984

Pediatric digital subtraction angiography.

Experience with intravenous digital subtraction angiography (DSA) in infants and children is limited, although its relative ease of performance, low complication rate, and diagnostic accuracy indicate great potential. We performed 87 DSA examinations (74 patients) and obtained sufficient detail to facilitate diagnosis in most cases. The major problems of patient movement and overlapping vessels can be minimized by judicious use of sedation and strict attention to technique. Exposure of patients to radiation has not been a limiting factor since our system uses low exposure factors (2-38 mR [.51-9.76 mu C/kg]/frame). Our results demonstrate that DSA has wide applicability to many organ systems and is especially useful in intracranial disease and for preoperative evaluation of neoplasms. More specific indications for its use in children must await further correlative studies.

Adolescent↗
PubMed1980

Lack of oncogenicity with immunosuppressive therapy.

The effect of immunosuppressive therapy on the incidence of malignancy was examined in BALB/c mice. In a short (31-week) protocol study, malignancy was induced by inoculating animals with 10(2.1) ID50 of lymphatic leukemia virus. Antilymphocyte antiserum and azathioprine increased the mortality and shortened the latency period of leukemia. Combining these two agents had a synergistic effect. The concept of immunological surveillance was investigated in a long-term protocol using the identical animal and immunosuppressive systems. Mice did not receive leukemia virus and were observed for development of spontaneous malignancy. Significant immunodepression was demonstrated after 348 days of immunosuppressive therapy. After two years, all surviving animals were killed and examined for neoplasia. There was no evidence that immunodepression increased the incidence of spontaneous malignancy. Immunosuppression adversely influenced exogenously administered, virus-induced murine leukemia. However, immunosuppressive therapy was not innately oncogenic and the concept of immunological surveillance was not confirmed.

Animals↗
PubMed1980

Primary neuroblastoma uptake of 99mtechnetium methylene diphosphonate.

Forty patients, ages three days to 12 years, with neuroblastomas had bone scans with 99mtechnetium methylene diphosphonate (99mTc-MDP) as part of their pretreatment examination. Twenty-four (60%) had primary tumor uptake and 16 (40%) did not. No difference was seen between the two groups in the incidence of tumor calcification or necrosis. No relationship between the level of urinary vanillylmandelic acid (VMA) and the presence of primary tumor uptake of 99mTc-MDP was found. The possible causes for the localization of 99mTc-MDP are discussed.

Adrenal Gland Neoplasms↗
PubMed1979

Myasthenia gravis treated with purified antithymocyte antiserum.

The therapeutic effect of goat anti-human thymocyte antiserum globulin (ATG) was assessed in 10 patients with myasthenia gravis. All subjects had far-advanced, debilitating disease poorly responsive to anticholinesterase therapy. Prolonged, low-dose ATG therapy was used, with 1.0 to 2.6 gm ATG protein administered intramuscularly over a 28- to 73-day period. Therapeutic responses of varying degrees were noted in 8 of 10 patients. Completion of a course of ATG treatment and discontinuation of the drug did not lead to acute relapse. Follow-up examinations for over 5 years have been maintained. A mean remission period of approximately 2 years was observed. This therapy deserves further evaluation; subjects with progressive myasthenia gravis despite prior thymectomy may represent ideal candidates.

Adolescent↗
PubMed1976

Antithymocyte antiserum therapy in myasthenia gravis.

The therapeutic effect of goat anti-human thymocyte antiserum globulin (ATG) was assessed in 10 patients with myasthenia gravis. Prolonged, low dose therapy was used with 1-0--1-6 grams protein administered intramuscularly over a 28-73 day period. Varying degrees of therapeutic response were noted in 8 patients. Fllow-up examinations for over 5 years have been maintained and relapse rates determined. The clinical criteria for aptients selection and characteristics of therapeutic response are presented.

Adolescent↗