Biomedical subjects

G A Andrews

Publications and source records attributed to G A Andrews.

At least 19 recordsLinked to original sources

PubMed1992

Production, characterization, and applications of a murine monoclonal antibody to dog erythrocyte antigen 1.1.

A murine IgM monoclonal antibody, which recognizes dog erythrocyte antigen (DEA) 1.1, has been produced. The antibody correctly identified canine RBC possessing DEA 1.1 in a panel of RBC typed by an independent laboratory. Reactivity of the monoclonal antibody was compared with canine anti-DEA 1.1 antiserum with 163 RBC samples from 145 dogs. Results of agglutination tests with the 2 reagents were in agreement for all samples. A card agglutination test that uses the monoclonal antibody with blood is described. A monoclonal antibody-based test should facilitate blood typing for DEA 1.1 in clinical practice.

Agglutination Tests↗

PubMed1992

N-glycolylneuraminic acid and N-acetylneuraminic acid define feline blood group A and B antigens.

Blood group incompatibility causes transfusion reactions and neonatal isoerythrolysis in cats. We investigated the molecular nature of the blood group antigens from cats that had blood type A, B, and AB erythrocytes. Naturally occurring anti-type B antibodies, Triticum vulgaris lectin, monoclonal antibody (MoAb) 32-27, and MoAb R-24 were used in agglutination tests, Western blots, and thin-layer chromatography (TLC) enzyme immunostaining. Type A erythrocytes had NeuGc-NeuGc-Galactose-Glucose-Ceramide ([NeuGc]2GD3) where NeuGc represents N-glycolylneuraminic acid, and NeuAc-NeuGc-GD3, where NeuAc represents N-acetylneuraminic acid, and may have [NeuGc]2 disialylparagloboside and NeuAc-NeuGc-disialylparagloboside. Type B erythrocytes only had [NeuAc]2GD3. Type AB erythrocytes had [NeuGc]2GD3, NeuAc-NeuGc-GD3, and [NeuAc]2GD3. Blood group antigens were also found on a 50-Kd membrane protein. We conclude that type B erythrocytes are characterized by [NeuAc]2GD3 as the only form of this ganglioside and the presence of NeuAc on a 50-Kd membrane protein. NeuGc is the major determinant of the A antigen; specifically, [NeuGc]2GD3 is the major glycolipid form. The A antigen is also present on a 50-Kd membrane protein.

ABO Blood-Group System↗

PubMed1992

Reactivity of lichen lectins with blood typed canine erythrocytes.

Extracts from 69 species of lichens were tested for their ability to agglutinate untreated and enzyme-modified erythrocytes from a panel of blood typed dogs. Forty-three lichen species reacted positively with either untreated or enzyme-modified cells. Many extracts exhibited differential agglutination among red cells tested. The patterns of differential agglutination observed with the lichen extracts did not correspond to known canine blood groups present on the test red cell panel.

Animals↗

PubMed1992

Inhibition of equine complement activity by polysulfated glycosaminoglycans.

The ability of polysulfated glycosaminoglycans (PSGAG) to inhibit the complement cascade was evaluated. The role of complement in inflammation and infection has been well documented. Inhibition of the complement cascade by PSGAG could explain why intra-articularly administered PSGAG diminish diarthrodial joint inflammation and potentiate septic arthritis in horses. Hemolytic complement testing was performed to evaluate the effect of PSGAG on the equine classical and alternate pathways of complement, using rabbit erythrocytes as the target cells. Concentration of PSGAG between 0.2 mg/ml and 0.6 mg/ml significantly (P less than 0.05) inhibited equine complement in dose-related fashion. Further increase in complement inhibition was not observed at PSGAG concentration greater than 0.6 mg/ml. Difference was not apparent in the extent of inhibition of complement from each of the 4 horses tested. Polysulfated glycosaminoglycans appeared to inhibit the classical and alternate complement pathways equally, indicating possible effect on complement components common to both pathways. Heat inactivation of complement function completely inhibited (P less than 0.01) the hemolytic activity of the serum from all horses.

Animals↗

PubMed1980

Unintentional intra-arterial injection of a bone-imaging agent.

The inadvertent intra-arterial injection of a dose of Tc-99m-MDP is reported. Limited quantitative studies were done on the distribution pattern. More extensive investigations of cases of this type may yield useful data on the behavior of radiopharmaceuticals.

Diphosphonates↗

PubMed1979

Carbon-11-labeled amino acids for the rectilinear and positron tomographic imaging of the human pancreas.

Modification of the Bücherer-Strecker amino acid synthesis facilitated the production of DL-[11C]tryptophan and DL-[11C]valine for clinical trials in patients with proven or suspected pancreatic disease. Examples of rectilinear scans and tomographic images of the pancreas are presented in this initial paper. Positron computed tomography was done with the ORTEC ECAT system. Rapid localization of these C-11-labeled amino acids and fast clearance from the plasma permit almost immediate examination following i.v. injection. Illustrative images include the normal pancreas, pancreatitis, and pancreatic carcinoma. The use of positron tomobraphy with C-11-labeled DL-tryptophan and DL-valine appears to offer a new and promising diagnostic modality for the detection and study of pancreatic diseases.

Carbon Radioisotopes↗

PubMed1978

Histopathologic studies of the liver following intravenous colloidal 198Au therapy.

Histologic studies of liver tissue from 27 patients given up to 395 mCi (cumulative) of intravenous colloidal 198Au showed no definite radiation injury and no correlation between hepatic abnormalities and dose. Demonstration of aggregates of colloidal gold in the Kupffer cells was inconsistent, suggesting slow removal or dispersion. Although the liver ordinarily receives the highest radiation dose, the critical organ is the marrow. Results support the recent introduction of 198Au to supplement teletherapy for certain neoplasms diffusely infiltrating the liver. Apparently the beta distribution minimizes endothelial injury in large vessels, which has been shown to be the cause of radiation hepatitis.

Adolescent↗

PubMed1978

Ga-67 citrate imaging in tumors of the genito-urinary tract: report of cooperative study.

Whole-body imaging with Ga-67 citrate in 127 tumors of the genito-urinary tract has been evaluated by a cooperative group using a uniform protocol. Primary sites of tumor were not detectable by imaging, except for one bladder and one kidney tumor. Proven and apparent metastases yielded positive scans, however, in 51% of prostatic, 50% of bladder, 72% of kidney, and 53% of testicular neoplasms. In bladder and kidneys metastases, if bone sites are excluded, detection of soft tissue metastases was 61% and 75%, respectively. In embryonal-cell carcinoma of the testicle, 74% of metastatic foci were detected.

Adenocarcinoma↗

PubMed1978

Ga-67 citrate imaging in malignant lymphoma: final report of cooperative group.

In a large cooperative study of Ga-67 uptake in non-Hodgkin's malignant lymphoma, 76% of untreated patients showed positive uptake in one or more lesions. The percentage of known individual lesions seen on scan was significantly lower; thus, negative findings at any one site may have much less significance than positive findings. After treatment, the number of lesions seen decreases sharply, but the role of Ga-67 in evaluating response to therapy is uncertain, especially in view of the fairly large number of lesions undetectable before therapy. Histologic type plays a role in Ga-67 uptake. Large lesions are much more effectively detected than small ones. In spite of numerous false-negative results, Ga-67 scanning is a useful method in evaluating the extent of untreated disease and the presence of lesions posttherapy.

False Negative Reactions↗

PubMed1977

The use of rare-earth radionuclides and other bone-seekers in the evaluation of bone lesions in patients with multiple myeloma or solitary plasmacytoma.

Twenty-four patients with multiple myeloma and 4 with solitary plasmacytoma had total-body scans after intravenous injection of 67Ga-citrate alone (17 patients) or combined with other agents (11 patients). The latter included 99mTc-diphosphonate (99mTc-DP), 99mTc-polyphosphate (99mTc-PP), or 99mTc-sulfur colloid (99mTc-SC) given alone or combined with 171Er, 157Dy, or 167Tm as citrate. In some patients more than one agent was compared to 67Ga and radiographic bone surveys. In general, localization of the rare-earth "bone-seekers" was poor except for 157Dy, which compared well with 99mTc-PP and 99mTc-DP; 157Dy was also helpful in studies of the abdomen and pelvis because of its failure to concentrate in the gastrointestinal tract. No toxic or nonspecific effects were noted.

Dysprosium↗

PubMed1977

Tumor location with 1-aminocyclopentane [11C] carboxylic acid: preliminary clinical trials with single-photon detection.

High specific activity [11C] Carboxyl-labeled 1-aminocyclopentane-carboxylic acid ([11C] ACPC) was tested as a tumor-scanning agent in thirty-eight patients. This artificial amino acid clears the blood to a level of less than 12% within 45 min; thus, imaging is possible within the useful life of C-11. [11C] ACPC can be produced in amounts adequate for clinical scanning. Doses between 12 and 45 mCi were given by i.v. injection, and scans obtained only in the single-photon mode gave clinical information on the sites of tumors. There was no evidence of any toxic effects from [11C] ACPC, and the radiation doses as extrapolated from animal data are approximately 0.01 rad per mCi for the whole body and less than 0.06 rad per mCi for the pancreas. In all but five of the 38 patients [11C] ACPC scans were compared with those obtained with Ga-67 citrate. There were 19 positive [11C] ACPC scans and 24 positive Ga-67 scans. The results indicate that [11C] ACPC is likely to be of diagnostic value for cancer patients if used in conjunction with positron tomography instrumentation.

Amino Acids↗

PubMed1977

Gallium-67 citrate imaging in Hodgkin's disease: final report of cooperative group.

A large cooperative study of Ga-67 uptake in Hodgkin's disease showed that 88% of untreated patients had a positive uptake in one or more lesions. The percent of individual lesions seen on scan, however, was significantly lower; this indicated that negative findings at any one site do not argue strongly against the possiblilty of a lesion there. After treatment, the number of visualized lesions decreased sharply, but the exact role of Ga-67 in evaluating therapy is still not clear. Of the various histologic types of Hodgkin's disease, there was a high incidence of localization in all except the lymphocyte-predominance type, which showed a slightly lower uptake. No lesions less than 1 cm in diameter were successfully imaged and the size most easily detected was 4 cm in diameter. As expected, the imaging technique was much less successful for abdominal lesions than for those at other sites because of interfering concentration in bowel and liver. Both radiotherpy and chemotherapy tend to reverse the abnormalities seen on scan. The finding of a significant number of unsuspected positive lesions in asymptomatic patients returning for routine followup suggests that this is a distinctly valuable use of Ga-67, allowing early therpy for recurrences.

Gallium Radioisotopes↗

PubMed1975