Biomedical subjects

B Lundgren

Publications and source records attributed to B Lundgren.

At least 91 records · Page 5Linked to original sources

PubMed1992

Antibody responses to a major Pneumocystis carinii antigen in human immunodeficiency virus-infected patients with and without P. carinii pneumonia.

Antibody responses to a major purified human Pneumocystis carinii surface antigen (gp95) were determined by ELISA in human immunodeficiency virus (HIV)-infected patients. Serum IgG directed against gp95 was measured in 129 consecutive HIV-infected patients who underwent bronchoscopy for evaluation of pulmonary symptoms. Significantly more patients with P. carinii pneumonia (PCP) had detectable antibodies compared with HIV-infected patients without PCP and with HIV-negative controls (50 [66%] of 76 vs. 18 [34%] of 53 and 7 [35%] of 20, respectively; P less than .001), and the level of antibody response was higher (mean optical density ratio: 0.6 vs. 0.23 and 0.2, respectively; P less than .01). Changes in antibody response were investigated in 78 patients for whom serial serum samples taken around the time of bronchoscopy were available. Of the 47 patients with verified PCP, 20 (43%) mounted an antibody response, compared with only 1 (3%) of 31 patients without PCP (P less than .001). This patient had PCP on the basis of clinical criteria, including response to therapy. Thus, despite severe immunosuppression, a proportion of HIV-infected patients with PCP can mount a specific IgG-mediated antibody response to P. carinii.

Antibodies, Fungal↗

PubMed1992

Pneumocystis carinii and specific fungi have a common epitope, identified by a monoclonal antibody.

Because Pneumocystis carinii may be related to fungi, we evaluated the reactivities of monoclonal antibodies raised against P. carinii with a variety of fungi. Fifty-two fungi and six protozoa were evaluated by immunofluorescence. One of three monoclonal antibodies (MAbs) tested (MAb 7D7) reacted with 15 fungi but no protozoa. Saccharomyces cerevisiae showed the strongest reactivity by immunofluorescence. The reactive antigen was characterized for four fungi by the immunoblot technique. In all cases the antigen that was reactive with MAb 7D7 was larger than the P. carinii antigens that reacted with 7D7. In further studies with P. carinii, Aspergillus species, and S. cerevisiae, we found that MAb 7D7 reacted with a carbohydrate component in all organisms. The presence of an epitope that is common to P. carinii and a number of fungi further supports the fungal nature of P. carinii.

Antibodies, Monoclonal↗

PubMed1992

Aqueous humor polyamines and alkaline phosphatase activity in endotoxin-induced uveitis: correlations to diverse leukocyte subsets.

The polyamines putrescine, spermidine and spermine have been proposed to be a part of the acute phase inflammatory response. They have been shown to be useful markers for cellular kinetics and change with various pathological conditions. The hypothesis that aqueous humor polyamines could be used to follow the time course of an endotoxin-induced inflammation in the eye was investigated. Additional parameters studied were the amount of aqueous leukocytes, alkaline phosphatase activity, distribution of leukocyte subsets and breakdown of the blood-aqueous barrier. Aqueous leukocytes, protein, alkaline phosphatase activity, putrescine and acetylated spermidine increased significantly as a response to inflammation during the first days after uveitis induction. Spermidine decreased 24 h after injection and seemed to rise thereafter. The different polyamines, except spermidine, correlated to the diverse infiltrating leukocyte subsets. These observations indicate that aqueous polyamines may be applied as valid markers for inflammation in the eye.

Alkaline Phosphatase↗

PubMed1992

Interaction of phospholipids with rhodamine 6G in toluene.

Upon interaction of various glycerophospholipids with Rhodamine 6G in toluene, a typical difference spectrum with an absorption maximum at approximately 515 nm is obtained . This spectrum is obtained with phosphatidylcholine only after treatment with NaCl, which presumably weakens intra- and/or inter-molecular electrostatic binding between the negatively charged phosphate moiety and the protonated nitrogen in this molecule. Absorption at 515 nm was linear for all of the phospholipids investigated from a concentration of approximately 1.2 microM up to at least 50 microM. The highest extinction coefficient was obtained for diphosphatidylglycerol (251 mM-1 cm-1) and all of the compounds tested, with the exception of phosphatidylethanolamine, demonstrated extinction coefficients higher than that of palmitic acid. Thus, the absorption spectrum which results from the interaction of purified glycerophospholipids with Rhodamine 6G in organic solvent is a sensitive measure of the amount of phospholipid present.

Coloring Agents↗

PubMed1992

Secondary cataract. An in vivo model for studies on secondary cataract in rabbits.

Secondary cataract formation is the most common postoperative complication following cataract surgery. To study different methods preventing the secondary cataract formation a relevant animal model is required. An in vivo rabbit model for studies on the prevention of secondary cataract formation is presented. The lens nucleus and cortex were removed by phacoemulsification, and two months later the growth of the secondary cataract was estimated by scoring on a scale from 0-4, both central and peripheral, and by measuring the wet mass of the dissected secondary cataract. The model seems to be a relevant way to study different concepts for the prevention of secondary cataract formation.

Animals↗

PubMed1991

Studies on the intracellular distributions of soluble epoxide hydrolase and of catalase by digitonin-permeabilization of hepatocytes isolated from control and clofibrate-treated mice.

Digitonin permeabilization of hepatocytes from control and clofibrate-treated (0.5% by mass, 10 days) male C57bl/6 mice was used to study the intracellular distributions of soluble ('cytosolic') epoxide hydrolase and of catalase. The following conclusions were drawn. (1) About 60% of the total soluble epoxide hydrolase activity in control mouse hepatocytes is situated in the cytosol. (2) The rest is not mitochondrial, but probably peroxisomal. (3) Of the total catalase activity in control mouse hepatocytes, 5-10% is found in the cytosol. (4) Treatment of mice with clofibrate increases the total hepatocyte activity of soluble epoxide hydrolase 4-fold, but does not influence the relative distribution of this enzyme between cytosol and peroxisomes. (5) The total catalase activity is increased 3.5-fold by clofibrate treatment and 15-35% of this activity is shifted from the peroxisomes to the cytosol.

Animals↗

PubMed1991

Eosinophil cationic protein stimulates and major basic protein inhibits airway mucus secretion.

Possible roles of eosinophil (EO) products in modulating the release of mucus from airway explants were investigated. Cell- and membrane-free lysates from purified human EOs (1 to 20 x 10(5)) caused a dose-dependent release of respiratory glycoconjugates (RGC) from cultured feline tracheal explants. Crude extracts from isolated EO granules also stimulated RGC release, suggesting that a granular protein might be responsible. Three proteins derived from EO granules, EO-derived neurotoxin, EO cationic protein (ECP), and major basic protein (MBP) were separated by sequential sizing and affinity chromatography. ECP (0.025 to 25 micrograms/ml) caused a dose-dependent increase in RGC release from both feline and human airway explants and also stimulated the release of the serous cell-marker, lactoferrin, from human bronchial explants. EO-derived neurotoxin (0.025 to 50 micrograms/ml) failed to affect RGC release, whereas MBP (50 micrograms/ml) significantly inhibited RGC release from feline explants. Thus, ECP stimulates RGC and lactoferrin release from airway explants, whereas MBP inhibits RGC release.

Airway Obstruction↗

PubMed1991

Purification and characterization of a major human Pneumocystis carinii surface antigen.

Previous studies of Pneumocystis carinii have identified the major surface antigen of rat and human isolates as proteins of 116,000 and 95,000 mol wt, respectively, that are antigenically not identical. In this study both rat and human P. carinii proteins were purified by solubilization with zymolyase followed by molecular sieve and ion exchange chromatography. The native proteins had an apparent mol wt of 290,000 or greater, based on molecular sieve studies as well as cross-linking studies. Both proteins were glycoproteins; treatment with endoglycosidase H resulted in a 9% decrease in mol wt. The carbohydrate composition of the rat P. carinii glycoprotein was distinct from the human isolate; glucose, mannose, galactose, and glucosamine occurred in approximately equimolar ratios in the human P. carinii protein, whereas glucose and mannose were the predominant sugars of the rat P. carinii protein. To evaluate humoral immune responses to the human P. carinii protein, an enzyme-linked immunosorbent assay using purified protein was developed. Some, but not all, patients who subsequently developed P. carinii pneumonia demonstrated a serum antibody response to the surface antigen. Nearly all subjects without a history of P. carinii pneumonia had no detectable antibodies. Purified P. carinii proteins will greatly facilitate the investigation of host-P. carinii interactions.

Animals↗

PubMed1991

Antiviral effects of 3'-fluorothymidine and 3'-azidothymidine in cynomolgus monkeys infected with simian immunodeficiency virus.

An acute infection with simian immunodeficiency virus (SIVSM) in cynomolgus monkeys was used to evaluate the antiviral effects of 3'-fluorothymidine (FLT) and 3'-azidothymidine [zidovudine (ZDV)]. Neither compound prevented the infection despite dosing prior to virus inoculation. FLT was about ten times more potent than ZDV in delaying the appearance of SIVSM antigen in the monkeys. The serum half-life of FLT was longer than that of ZDV and ZDV was bound to plasma proteins to about 60% while FLT was virtually unbound. It is proposed that the in vivo difference in potency between ZDV and FLT could, at least partly, be explained as the combined effects of a longer plasma half-life and a higher free concentration of FLT and possibly a higher intracellular concentration of the triphosphate of FLT.

Animals↗

PubMed1990

Effects of dietary treatment with clofibrate, nafenopin or WY-14.643 on mitochondria and DNA in mouse liver.

Male C57bl/6 mice were administered clofibrate (0.5%, w/w), nafenopin (0.125%, w/w) or WY-14.643 (0.125%, w/w) in their diet for 4 days. Assay of eight mitochondrial marker enzymes, -i.e., malate and glutamate dehydrogenases (matrix markers), cytochrome oxidase and cytochromes c + c1 and a (inner membrane), adenylate kinase (intermembrane space) and monoamine oxidase and microsomal glutathione transferase (outer membrane)--and morphometric analysis of electron micrographs was used to examine hepatic mitochondria after treatment with these peroxisome proliferators. A moderate increase in the number of hepatic mitochondrial profiles, with a simultaneous decrease in the average size of these organelles, was observed. The total mitochondrial volume is apparently unchanged during this process. An important experimental consequence of the apparent decrease in mitochondrial size is the redistribution of a large portion of the total hepatic mitochondria from the 'nuclear' to the mitochondrial fraction. A similar effect was seen with rats.

Animals↗

PubMed1990

Identification of Pneumocystis carinii chromosomes and mapping of five genes.

Pulsed field gel electrophoresis was used to identify the chromosome-size DNA of Pneumocystis carinii, a major pathogen of immunocompromised patients. Thirteen chromosomes of rodent Pneumocystis carinii, ranging in size from 300 to 700 kilobases (kb), were identified. The minimum genome size for P. carinii, estimated on the basis of the sizes of chromosomes, is 7,000 kb. Genetic heterogeneity among different P. carinii isolates was documented by demonstration of chromosomal size variability. By hybridization studies, the genes for topoisomerase I, dihydrofolate reductase, rRNA, actin, and thymidylate synthase were mapped to single chromosomes of approximately 650, 590, 550, 460, and 350 kb, respectively. Hybridization studies further confirmed the genetic heterogeneity of P. carinii.

Actins↗

PubMed1990

The metabolism of xenobiotics and its relationship to toxicity/genotoxicity: studies with human lymphocytes.

Most compounds considered to be foreign to the human body are rather hydrophobic and chemically inert. Because of their hydrophobicity, xenobiotics enter the body easily by diffusion through biological membranes, are difficult to excrete in unchanged form in the urine and bile and accumulate in hydrophobic compartments of the cell, including the phospholipid bilayer of membranes, where they can disturb normal cellular functions. In order to transform xenobiotics into products which are more readily excretable, enzymes of detoxication first activate these substances (primarily via the cytochrome P-450 monooxygenase system) to intermediates which are often highly electrophilic and reactive, such as epoxides, free radicals and carbonium ions. These intermediates are then partially inactivated and their solubility in water simultaneously increased through the addition of water (by epoxide hydrolases) or conjugation with glutathione (by glutathione transferases). Finally, an additional increase in water solubility can be achieved by conjugation with, for example, sulfate (via sulfotransferases) and/or glucuronic acid (via UDP-glucuronyltransferases). Unfortunately, reactive intermediates of xenobiotic metabolism which are not inactivated sufficiently rapidly can bind covalently to many nucleophilic groups in the cell, including those on DNA, RNA and protein. Most often, because of various cellular defense mechanisms, such binding causes no serious damage. However, in some cases toxic and/or genotoxic effects may be produced. As an alternative to experimentation with animals, we have examined xenobiotic metabolism in circulating mononuclear leukocytes from human beings. Certain enzymes of detoxication--including membrane-bound and cytosolic epoxide hydrolases and cytosolic glutathione transferases--can be easily measured and characterized in preparations from these cells. Autosomal dominant hereditary differences of at least several hundred-fold in the activity of glutathione transferase mu in circulating human lymphocytes were observed, differences which may be of value in predicting an individual's risk for toxic/genotoxic damage after exposure to certain xenobiotics.

Humans↗

PubMed1989

Isolation and expression of the Pneumocystis carinii thymidylate synthase gene.

The thymidylate synthase (TS) gene from Pneumocystis carinii has been isolated from complementary and genomic DNA libraries and expressed in Escherichia coli. The coding sequence of TS is 891 nucleotides, encoding a 297-amino acid protein of Mr 34,269. The deduced amino acid sequence is similar to TS from other organisms and is most closely related to the enzyme from Saccharomyces cerevisiae with 65% identity. TS is found on a 330-kilobase-pair chromosome in P. carinii. While TS and dihydrofolate reductase reside on a single polypeptide chain in all protozoa studied to date, TS is not linked to dihydrofolate reductase in P. carinii. The TS gene shows the presence of four small intervening sequences, some of which interrupt the coding sequence in highly ordered structural regions of the protein. Heterologous expression of P. carinii TS in E. coli was accomplished by cloning the coding sequence into plasmid vectors under control of the lac and tac promoters. These constructs direct the synthesis of catalytically active enzyme to the extent of 2% of total soluble protein.

Amino Acid Sequence↗

PubMed1989

Isolation and expression of the Pneumocystis carinii dihydrofolate reductase gene.

Pneumocystis carinii dihydrofolate reductase (DHFR; 5,6,7,8-tetrahydrofolate: NADP+ oxidoreductase, EC 1.5.1.3) cDNA sequences have been isolated by their ability to confer trimethoprim resistance to Escherichia coli. Consistent with the recent conclusion that P. carinii is a member of the Fungi, sequence analysis and chromosomal localization show that DHFR is neither physically nor genetically linked to thymidylate synthase. Expression of recombinant P. carinii DHFR in heterologous hosts provides an abundant source of the enzyme that may form a basis for the development of new therapies for this enigmatic pathogen. Studies with the recombinant enzyme show that trimethoprim is a very poor inhibitor of P. carinii DHFR and, in fact, is a more potent inhibitor of human DHFR.

Amino Acid Sequence↗

PubMed1989

Monoclonal antibodies to Pneumocystis carinii: identification of specific antigens and characterization of antigenic differences between rat and human isolates.

To increase understanding of the antigenic structure of Pneumocystis carinii, we developed monoclonal antibodies to rat and human P. carinii. The specificity of the antibodies was demonstrated by immunofluorescence and immunoblot studies. Only one of five monoclonal antibodies to rat P. carinii reacted with human P. carinii, and none of four monoclonal antibodies to human P. carinii reacted with rat P. carinii. Two antibodies to human P. carinii reacted by immunofluorescence with only one human P. carinii isolate. Immunoblot studies identified major antigens of rat P. carinii with molecular masses of 40,000-100,000 daltons and of human P. carinii with molecular masses of 22,000-95,000 daltons. These studies document the existence of antigenic differences between rat and human P. carinii and are consistent with the suggestion that individual isolates of human P. carinii are also antigenically different. Further studies with these antibodies should increase understanding of the antigenic nature of P. carinii and of the interaction of P. carinii with its host.

Animals↗

PubMed1989

Conception rate for infertile couples. The importance of anamnesis and signs of genital disease in men with abnormal semen findings.

During a 4-year period, 259 men were investigated for primary (86%) or secondary (14%) infertility. Some 3-5 years after the initial investigation, a follow-up study of conception rate, was performed in 200 of these cases. Conception had occurred in 79 couples (39%). Sperm density was lower among men with a history of genital disease(s) than amongst men without such a history, but conception rate was not influenced by a positive history. Men with signs of genital disease(s) had lower sperm density, a smaller proportion of morphologically normal spermatozoa and lower sperm motility, than men with a normal finding at physical examination. Men with such signs had the same conception rate as men with normal physical findings. The only subgroup, in which conception rate was lower than in men with no physical abnormalities, was men with palpatory abnormal epididymis(des).

Female↗

PubMed1989

Proliferation of peroxisomes and induction of cytosolic and microsomal epoxide hydrolases in different strains of mice and rats after dietary treatment with clofibrate.

1. The effects of dietary clofibrate (0.5%, w/w, for 10 days) on seven inbred strains of mice--C57BL/6, C57BL/B10A(5R), ATL/OLA, C3H/HE/OLA, BALB/C, CBA/CA and A/J/OLA--and three strains of rats--Sprague-Dawley, Wistar and LOU/OLA--have been investigated. Liver weight, peroxisome proliferation, catalase activity, cytosolic, microsomal and mitochondrial epoxide hydrolase activities, cytochrome oxidase activity, microsomal cytochrome P-450 content and cytosolic glutathione transferase activity in liver were determined, together with cytosolic and microsomal epoxide hydrolase and cytosolic glutathione transferase activities in the kidneys. 2. In all cases peroxisome proliferation and induction of cytosolic epoxide hydrolase were observed in livers of rodents exposed to clofibrate. Thus, no non-responsive strains were found and further evidence for a coupling between these two phenomena was provided. In many cases significant increases in the liver microsomal cytochrome P-450 content and decreases in the hepatic cytosolic glutathione transferase activity were also seen. 3. High levels of cytosolic epoxide hydrolase were found in the rat kidney. In several strains of mice and rats renal cytosolic epoxide hydrolase activity was increased by clofibrate. 4. There were often considerable strain differences. However, in general mice had higher cytosolic epoxide hydrolase and glutathione transferase activities, whereas rats had higher microsomal epoxide hydrolase activities.

Animals↗

PubMed1989

Experimental infection of cynomolgus monkeys (Macaca fascicularis) with simian immunodeficiency virus (SIVsm).

Five healthy cynomolgus monkeys were inoculated intravenously with simian immunodeficiency virus (SIVsm) propagated in human lymphocytes. All five animals became infected. Virus was recovered from blood mononuclear cells and viral antigen was detected in serum 12 days postinoculation (PI) in all inoculated animals. Virus was also isolated in all five animals tested 74 to 226 days PI. Antibodies to different structural proteins of SIV and HIV-2 were demonstrated by ELISA, Western blot, and radioimmunoprecipitation assay from day 31 PI concomitantly with a reduction of viral proteins in the serum. Reappearance of antigen accompanied by a fall in antibody to gag products (p26) was observed in two monkeys 69 days PI. All SIV-infected monkeys showed a pronounced decrease in CD4+ lymphocytes demonstrable already 12 days PI. They also developed persistent lymphadenopathy. Thus, infection of cynomolgus monkeys with SIVsm mimics events in human immunodeficiency virus infection in humans but the course of evolution of pathogenic events in the monkey is markedly compressed. This experimental model will be useful for evaluation of HIV vaccines and antiviral testing.

Acquired Immunodeficiency Syndrome↗