Search PubMed⌕ Search

Biomedical subjects

R Montgomery

Publications and source records attributed to R Montgomery.

At least 55 records · Page 3Linked to original sources
PubMed1991

External fistulas arising from the digestive tract.

External abdominal fistulas that arise from the digestive tract are associated with high mortality and prolonged morbidity in terms of infection, malnutrition, and skin excoriation. Such external fistulas most commonly follow anastomotic leak after gastrointestinal surgery. We identified 58 patients seen over a 5-year period at the University of Louisville Hospitals because of external abdominal fistulas that arose from the stomach (8), duodenum (4), small intestine (26), colon (14), biliary tract (9), and pancreas (7). Fifteen patients had multiple fistulas and 32 had high-output fistulas (greater than 200 mL/day). Closure was achieved in 48 patients, and eight of the 10 patients whose fistulas remained open died. Overall mortality was 19%. Principles of management include control of infection, correction of fluid and electrolyte imbalance, nutritional support, proper wound care, and often operative intervention. Multiple staged operations over many months were particularly important in managing complex wounds with large abdominal wall defects and multiple fistulas. Fistula closure is the ultimate goal, and patience is important to achieve it.

Abdomen↗
PubMed1991

Evaluation of cryopreserved bone and synthetic biomaterials in promoting spinal fusion.

The purpose of the study was to evaluate the use of cryopreserved allograft bone and tricalcium phosphate in promoting spinal fusion. Nine 20-30 lb swine underwent posterior spinal fusion at T5-T6, T13-T14, and L2-L3. Autogenous bone, cryopreserved allograft bone, or equal parts of allograft bone and tricalcium phosphate were added to the decorticated posterior elements. A total of 27 sites were prepared for fusion. The spines were retrieved at 6 months and evaluated for integrity and stability of the fusion sites by clinical examination, three-point bending tests, multiplanar radiographs, and undecalcified tetracycline-labeled and decalcified histologic sections. The nine sites that received autogenous bone were solidly fused. There were one clinical and two radiographic nonunions in the nine sites that received cryopreserved allograft bone. Sites that received a mixture of allograft bone and tricalcium phosphate demonstrated slight motion at two locations and radiographic evidence of fusion at all levels. The extent and degree of fusion was not site-specific. Three-point bending analysis did not demonstrate a significant trend as to site or materials specificity. No adverse histologic response was noted. Histologic sections and tetracycline labels confirmed abundant new bone formation at all sites at 6 months. Although autogenous bone remains the gold standard for use in spinal arthrodesis, this study demonstrates the value of cryopreserved allograft bone alone and in combination with tricalcium phosphate in promoting spinal fusion.

Animals↗
PubMed1989

Experimental and clinical significance of endotoxin-dependent HLA-DR expression on monocytes.

For much of the last decade, an increasing number of surgeons have been interested in objective assessment of cellular contributors to host defense function. In order to study many of these processes, it is apparently desirable that the cells be isolated to the extent feasible for the purpose of analyzing a more or less pure population of cellular elements. The purpose of this paper is to describe the physiologic activation of mononuclear cells that occurs as a result of the isolation process. Therefore, it follows logically that such cells are therein intrinsically less responsive to further physiologic manipulation in vitro. Analyses of such data without an awareness of this intrinsic aberration will undoubtedly lead to misinterpretation of the capacity of such cells for further modulation by immunostimulants or by the intrinsic processes related to injury, anesthesia, and operation. Furthermore, it may indicate that certain agents, e.g., cytokines, are unable to stimulate cellular function when, in fact, the defense function of the cell has been initially stimulated by the isolation procedure. Fractionation of human peripheral blood over Hypaque-Ficoll and subsequent purification of monocytes by adherence to plastic lead to an increase in the relative density of HLA-DR on monocytes. This increase occurred when carried out in endotoxin lipopolysaccharide (LPS)-contaminated or LPS-depleted reagents. LPS, added experimentally to whole blood, enhanced HLA-DR expression on monocytes without further manipulation. Monocyte HLA-DR expression measured in whole blood was reduced in patients with major sepsis (n = 19) compared to normal subjects (n = 10).(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies↗
PubMed1988

The comparative clearance rates of the pleural and peritoneal cavities.

We compared the rates of bacterial clearance from the pleural and peritoneal cavities of rats after contamination with 1 x 10(6) live Escherichia coli. Pleural clearance was enhanced beginning at 30 minutes after injection and extended to at least six hours. At 24 hours, the clearance was similar for both the pleural and peritoneal groups. Blood and organ bacterial cultures were similar between these two groups. White blood cell populations were similar at rest, but there was a greater increase in the leukocyte population in the pleural cavity six hours after E coli stimulation. We postulate that the increased clearance of E coli from the pleural cavity may be due to differences in lymphatic absorption, recruitment of leukocytes, or fibrin trapping of bacteria.

Animals↗
PubMed1986

Serospecific antigens of Legionella pneumophila.

Serospecific antigens isolated by EDTA extraction from four serogroups of Legionella pneumophila were analyzed for their chemical composition, molecular heterogeneity by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and immunological properties. The antigens were shown to be lipopolysaccharides and to differ from the lipopolysaccharides of other gram-negative bacteria. The serospecific antigens contained rhamnose, mannose, glucosamine, and two unidentified sugars together with 2-keto-3-deoxyoctonate, phosphate, and fatty acids. The fatty acid composition was predominantly branched-chain acids with smaller amounts of 3-hydroxymyristic acid. The antigens contain periodate-sensitive groups; mannosyl residues were completely cleaved by periodate oxidation. Hydrolysis of the total lipopolysaccharide by acetic acid resulted in the separation of a lipid A-like material that cross-reacted with the antiserum to lipid A from Salmonella minnesota but did not comigrate with it on sodium dodecyl sulfate gels. None of the four antigens contained heptose. All of the antigen preparations showed endotoxicity when tested by the Limulus amebocyte lysate assay. The results of this study indicate that the serogroup-specific antigens of L. pneumophila are lipopolysaccharides containing an unusual lipid A and core structure and different from those of other gram-negative bacteria.

Antigens, Bacterial↗
PubMed1986

Characterization of human interferon species using gel extraction and monoclonal antibodies: implications on clinical use of interferon preparations.

Human interferons from various sources have been characterized using sodium dodecyl sulfate polyacrylamide gel electrophoresis followed by electrotransfer onto nitrocellulose and reaction with specific polyclonal and monoclonal antibodies. When gel slices were extracted, alpha-interferon subspecies possessed antiviral activity predominantly in the 18.6-19.7K region bands, the beta-interferon in the 22.1K band, and gamma-interferon in the 16.5-18.0K bands. Three of the monoclonal antibodies (Ab 138, Ab 126, Ab 098) reacted with a characteristic triplet of biologically active bands (18.6K, 19.1K, 19.7K) obtained using the Namalwa cell interferons, while two (Ab 194 and Ab 232) reacted only with the 18.6K band and Ab 523 reacted with the 19.7K band. With the human leukocyte interferons, Ab 098, Ab 194, and Ab 232 reacted with the active 18.6K band. The Ab 138, Ab 126, and Ab 523 reacted specifically with certain lower molecular weight active bands (13K region). A comparison of the antiviral activity and reactivity towards monoclonal and polyclonal antibodies presents a differentiation of the subspecies of interferons in the wide array of closely related proteins in interferon preparations packaged for clinical use.

Antibodies, Monoclonal↗
PubMed1985

Peptidase activity of macromomycin apoprotein.

Macromomycin, an antibiotic and antitumor protein obtained from Streptomyces macromomyceticus, displayed specific aminopeptidase activity. Pure macromomycin degraded the beta-chain of insulin, a few synthetic di- and tripeptides, and a number of proteins of KB cell plasma membrane. The biological activity and the peptidase activity showed similar temperature-dependent patterns suggesting that one protein is responsible for both activities. The apoprotein contained the aminopeptidase activity while the chromophore, which displayed the antibiotic and antitumor activity, did not show any such activity.

Amino Acids↗
PubMed1985

Proteolytic activity of largomycin.

Largomycin, an antibiotic and antitumor protein, purified from the culture broth of Streptomyces pluricolorescens, displayed specific proteolytic activity. Pure largomycin did not degrade a number of substrates commonly used for detection of aminopeptidase, endopeptidase and carboxypeptidase activity. Pure largomycin degraded angiotensin II, bradykinin, a few dipeptides and a number of proteins of KB cell plasma membranes. The biological activity and the proteolytic activity of largomycin showed similar temperature-dependent patterns, suggesting that one protein is responsible for both activities. The apoprotein of largomycin, which did not show antibiotic activity, contained the proteolytic activity.

Aminoglycosides↗
PubMed1982

Largomycin: preparation, properties, and structure.

Largomycin has been purified to homogeneity by chromatography on hydroxylapatite whereby carbohydrate and protease impurities were removed. Largomycin is an acidic protein (pI 4.13, molecular weight 29300) which forms a dimer in phosphate buffer. An N-terminal amino acid sequence analysis from the amino-terminal residue gave, for the first 32 residues, Asp-Ile-Leu-Ile-Ala-Gly-Ala-Thr-Gly-Asn-Val-Gly-Lys-Pro-Leu-Val-Glu-Gly-Leu-Leu - Ala-Ala-Gly-Lys-Pro-Val-Arg-Ala-Leu-Thr-Arg-Asn... The sequence from the carboxyl terminus was -Ala-Ala-Leu-Phe-OH with threonine, valine, and glutamic acid being released upon prolonged digestion. The same amino acid sequences were found for largomycin prepared from either the culture broth or the mycelium of Streptomyces pluricolorescens. The similarities extended to the other physical properties, the antimicrobial activity against Staphylococcus aureus and Sarcina lutea, and the antitumor activity against KB cells. Largomycin inhibits the biosynthesis of DNA and RNA. An iodinated derivative did not bind to KB cells. The antimicrobial activity was lost following ultraviolet irradiation, protection against which was not afforded by p-aminobenzoic acid.

Amino Acid Sequence↗
PubMed1982

Antitumor proteins of Streptomyces macromomyceticus: purification and characterization of auromomycin, macromomycin A, and macromomycin D.

Macromomycin A and the two related proteins auromomycin and macromomycin D were isolated from the culture filtrates of Streptomyces macromomyceticus by chromatography on columns of DEAE-cellulose, Amberlite XAD-7, and decylagarose. Antibodies prepared against macromomycin A showed antigenic identity by Ouchterlony double diffusion between the three purified proteins. This similarity was further demonstrated by their behavior on disc gel electrophoresis, the amino acid compositions, and comparative peptide mapping of the aminoethylated derivatives. They differed, however, in other chemical and biological properties. Auromomycin and macromomycin A, pI 5.4, have antibiotic activity, which is absent in macromomycin D, pI 5.2. This antibiotic activity was associated with chromophore groups that were extractable by methanol. High-pressure liquid chromatography of the methanol extracts gave difference profiles for each of the purified proteins. The differences in the three proteins extended to their ultraviolet-visible spectra, fluorescence and circular dichroism, and the changes of these properties with heating. The heat denaturation, with auromomycin and macromomycin melting at 70.5 degrees C and macromomycin D at 57.0 degrees C, was reversible. Changes were noted in the spectra both during and following heating at 80 degrees C; the antibacterial activity was lost in auromomycin and only partially reduced in macromomycin A. The properties of the three proteins support the general similarities in their polypeptide structures, modifications in the properties of which are endowed by the differences in the associated nonprotein chromophores.

Amino Acids↗
PubMed1981

(Na+ + K+)-stimulated ATPase inhibition by cesalin and macromomycin.

(Na+ + K+)-stimulated ATPase was purified from dog kidney and its catalytic and glycoprotein subunits were separated. The enzymatic activity of the ATPase was totally inhibited by ouabain and partially inhibited by cesalin, maromomycin, concanavalin A, and wheat germ agglutinin. The inhibitions by cesalin or macromomycin can be reversed by the addition of phosphatidylethanolamine or phosphatidylserine, but not phosphatidylcholine. The specific binding of 125I-cesalin to the enzyme was inhibited by concanavalin A, wheat germ agglutinin, macromomycin, and the antibodies prepared in rabbits against the holoenzyme and the glycoprotein subunit, but not by ouabain, simple sugars, or the antibody against the catalytic subunit. It is proposed that the antitumor activities of cesalin and macromomycin are initiated in part by their binding to the glycoprotein subunit of (Na+ + K+)-ATPase in the plasma membrane.

Adenocarcinoma↗
PubMed1981

Cryoimmunoglobulinaemia in patients with renal disease. II attempts to demonstrate-that cryoprecipitate contain autoantibodies and/or antigen.

Seventeen patients found to have cryoimmunoglobulinaemia (CIG) while undergoing diagnostic renal biopsy and two patients with CIG without renal disease were studied. The cryoprecipitates (CP) from four of seven patients tested contained enhanced concentrations of autoantibodies: to vascular smooth muscle, autologous skeletal muscle, nuclear antigen and cardiac muscle. Antisera were made in rabbits against each of the 19 CP; six antisera contained antibodies to sarcolemma of skeletal muscle, nuclear antigen, elastin, reticulin, renal eluate and autologous kidney immune deposits respectively. Although one anti-CP antiserum bound to renal deposits, eight others tested on autologous renal biopsies did not. The data suggest that CP frequently may contain enhanced concentration of circulating autoantibodies and/or tissue antigens, possibly as immune complexes. In only one case was it possible to demonstrate that there was a common immunological identity between CP and renal Ig deposits.

Antigen-Antibody Complex↗
PubMed1980

Binding of cesalin, an antitumor protein, to cultured mammalian cells.

125-I-labelled cesalin binds to KB cells and plasma membranes in a specific and saturable manner. At 0 degrees C the cesalin specifically bound to cells is completely displaceable by excess unlabelled cesalin, but at 37 degrees C only 50% can be removed after incubation for 2 h. The extent of binding to plasma membranes has the following characteristics: it is increased following treatment of membranes with cholate; treatment with trypsin has no effect on binding and neither is the bound 125-I-labelled cesalin removed following digestion with trypsin; binding is not inhibited by several carbohydrates but is decreased to about one half by concanavalin A. In addition it is found that some degradation of cesalin occurs with KB cells, the specific binding to which is not enhanced by chloroquine, a lysosomotropic agent. No loss of binding in cells is seen after 4 h exposure to cesalin, suggesting no reduction in the receptors by internalization. The data are consistent with a mechanism in which 125I-labelled cesalin is rapidly bound at 37 degrees C to a receptor on cell membranes through which the biological activity is effected. Slowly, some change in the bound cesalin occurs that prevents its complete displacement from the cells.

Carcinoma↗