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Biomedical subjects

M Lynn

Publications and source records attributed to M Lynn.

At least 73 records · Page 4Linked to original sources
PubMed1984

Biochemical alterations in the mouse induced by Pseudomonas aeruginosa and its slime glycolipoprotein.

Mice, injected with either live cells of Pseudomonas aeruginosa, or its slime glycolipoprotein (GLP), developed similar lethal syndromes. Within 14 h, biochemical changes in the sera, such as increased urea, aspartate aminotransferase, alanine aminotransferase, and creatinine, as well as decreased glucose, albumin, total protein, uric acid, and alkaline phosphatase, indicated liver and renal dysfunction. These marked alterations were in contrast with the minimal histopathological changes that occurred in these organs. Either live cell or GLP challenge also induced haemolysis in vivo. Immunization with GLP protected mice against most biochemical changes when challenged with live cells but did not protect GLP-challenged mice against the biochemical alterations assayed in the sera.

Animals↗
PubMed1983

Induction of active immunity with membrane fractions from Haemophilus influenzae type b.

Using Escherichia coli strain E-1 as a model, we developed procedures for the preparation of outer- and inner-membrane-enriched fractions as structural units. These procedures could be used to prepare relatively pure inner and outer membrane fractions as determined by succinate dehydrogenase activity, ketodeoxyoctonate levels, and polyacrylamide gradient gel electrophoresis. The use of these procedures to fractionate membrane components from Haemophilus influenzae type b strains H-2 and H-E led to good separation of outer- and inner-membrane-enriched fractions as determined by succinate dehydrogenase and ketodeoxyoctonate levels but incomplete separation as determined by polyacrylamide gradient gel electrophoresis. Although there were differences between the electrophoresis profiles of outer membrane fractions of strains H-2 and H-E, immunization with outer membrane of either strain led to the induction of a high degree of immunoprotection against challenge with the H-2 strain. Protection could also be elicited with inner membrane preparations, but such protection may be due to contamination with outer membrane. Extracted membrane protein induced levels of protection that were comparable to those induced by whole membrane fractions.

Animals↗
PubMed1983

Naturally occurring antibodies in human sera that react with Haemophilus influenzae type b ribosomal vaccine.

Sera from populations of normal adults and children as well as sera from children with systemic Haemophilus influenzae type b disease were tested for antibodies reacting with ribosomes from H. influenzae type b. Adults generally had high titers of antibody, with 90% having titers greater than 1:64. The distribution of titers approximated a normal curve. Among normal children, there was more variability between individual titers, with the median titers ranging between 1:64 and 1:128. In contrast, acute-phase sera from children with systemic H. influenzae type b disease all had titers of 1:16 or less. Two convalescent-phase sera had high titers. Absorption experiments ruled out cross-reaction between ribosomes and type b capsular material. Ribosomes from two unrelated type b strains were completely cross-reactive, whereas absorption with ribosomes from a type c strain led to significantly decreased titers in three of four sera. Absorption of sera with ribosomes from Pseudomonas aeruginosa and Streptococcus pneumoniae also decreased titers, indicating that these antibodies may have been induced by ribosomes of other bacteria.

Adolescent↗
PubMed1983

Opsonization and phagocytosis of Haemophilus influenzae type B organisms by mouse polymorphonuclear leucocytes and antiribosomal serum.

Sera from rabbits immunized with ribosomes passively protect mice challenged with Haemophilus influenzae type b. The protective antibody interacted with organisms in the blood and possibly at the sites of dissemination, but not at the site of inoculation. Macrophages did not phagocytize oposonized bacteria in our system. However, immune serum enhanced phagocytosis and intracellular killing by polymorphonuclear leucocytes (PMN) by reducing viable counts by 77 to 93% and 35 to 50%, respectively. There was a strong correlation between opsonizing activity and passive protection in immune and normal serum. Inactivation of complement significantly reduced the opsonizing activity of the immune serum. A significant portion of the protection associated with the immune serum is localized in the IgM fraction. Immune serum, depleted of IgG, enhanced phagocytosis to a degree similar to intact immune serum. However, immune serum depleted of IgM, opsonized bacteria to the same degree as normal serum. Therefore, the immune component of serum responsible for protection and opsonization appears to be localized in the IgM fraction. These data indicate that protection induced by antiribosomal antibodies results from an interaction with the cell surface of H. influenzae organisms, leading to increased phagocytosis by PMN.

Animals↗
PubMed1981

Serological and biological activities of anti-Haemophilus influenzae ribosomal serum.

The antibody content in serum from rabbits immunized with ribosomes from Haemophilus influenzae type b was determined by passive hemagglutination, enzyme-linked immunosorbent assay, and complement fixation. Attempts to use passive hemagglutination to assay anti-ribosomal antibodies were unsuccessful. In the enzyme-linked immunosorbent assay tests, rabbit antiserum was allowed to react with ribosomes that adhered to microtiter plates. The enzyme-linked immunosorbent assay method detected, in two ribosome-immunized rabbits and by 3 days postimmunization, titers which rose to plateaus on days 24 to 31 and declined thereafter. With the complement fixation method, the serum from one immunized rabbit also showed a titer on day 3 and reached a plateau on days 20 to 31. Serum from the other immunized rabbit did not develop a titer until day 11; it reached a lower plateau on days 20 to 24 and then declined on days 27 to 55. Although there were no apparent differences between the two immunized rabbits by the enzyme-linked immunosorbent assay, there were differences between the complement fixation antibodies in these rabbits. Passive protection experiments were performed with these sera. Maximal passive protection was achieved when mice were challenged intraperitoneally with 100 50% lethal doses of H. influenzae and immunized intravenously 1 h later with rabbit serum collected 27 days postimmunization. Rabbit anti-ribosomal sera were evaluated for bactericidal activity. Undiluted immune sera showed bactericidal activity; however, when diluted 1:10, activity was lost. Although bactericidal activities of immune sera were correlated to passive protection activities, it is unlikely that such protection was due to bactericidal antibodies. Immune serum had opsonizing activity since it enhanced phagocytosis of H. influenzae by mouse leukocytes.

Animals↗
PubMed1981

Kinetics of Haemophilus influenzae type B infection in normal and ribosome-immunized mice using intraperitoneal and intracerebral routes of inoculation.

The kinetics of infection was studied in normal and ribosome-immunized mice challenged with Haemophilus influenzae Type b organisms. Ribosomal preparations extracted by the differential-centrifugation and sodium-dodecyl-sulphate treatment or ammonium-sulphate-precipitation procedures were highly immunoprotective when mice were challenged by the i.p. route. After i.p. injections, organisms rapidly spread to blood, liver, lungs and brain in normal and immunized mice. However, by 24 h after injection, evidence of organism clearance could be seen in immunized mice. By 32 h organisms were cleared from blood, brain and lungs of all immunized mice and from spleens in 2 of 3 mice. However, organisms persisted in high numbers of unimmunized mice until their death by 48 h. These data indicate that i.p. injections of H. influenzae mixed with gastric mucin leads to a true infection and can be used as a model to evaluate immunoprotective activity. The kinetics of infection induced by intracerebral (i.c.) inoculation also was studied. The LD50 for this type of infection was more than 1000 times the LD50 for i.p. infection. The patterns of infection induced by i.c. challenge were similar in normal and immunized mice and immunoprotection could not be detected using this model.

Animals↗
PubMed1979

The superiority of combination chemotherapy over single agent chemotherapy in small cell lung carcinoma.

From June 1974 to October 1976, 288 patients with small cell undifferentiated lung carcinoma were entered into a randomized, controlled study comparing the two noncycle-active induction regimens of cyclophosphamide vs. the combination of cyclophosphamide, doxorubicin and imidazole carboximide (DTIC). Patients were stratified by extent of disease, previous radiotherapy and performance status. Responding patients and those who did not progress were then randomized to receive their initial regimen alone, or their initial regimen with added cycle-active therapy (vincristine, hydroxyurea and methotrexate). While only 4/34 (12%) evaluable patients treated with cyclophosphamide achieved a response (greater than 50% regression), a final total of 119/217 (57%) evaluable patients on the three drugs have responded (p = 0.005). The survival curve for all the combination-treated patients was significantly better than for those treated with cyclophosphamide alone (p = 0.012). There was no demonstrable statistical superiority in length of remission or survival for patients on the combination who received in addition cycle-active consolidation therapy. In the combination chemotherapy group, survival duration was longer for patients with limited disease than extensive disease (p = 0.035). There was a strong correlation between quality of remission produced by the combination and survival.

Adult↗
PubMed1979

Role of bovine serum albumin in the nutrition of Mycobacterium tuberculosis.

Bovine serum albumin promotes the growth of small inocula of Mycobacterium tuberculosis in media containing unesterified fatty acids. Albumin binds fatty acids present in concentrations toxic for the organisms. In the present study, additional roles of albumin were investigated. When present in a basal medium, fatty acid-free albumin could be utilized by M. tuberculosis as a sole source of carbon. Since albumin could not substitute for the amino acids in basal medium as a nitrogen source, it was concluded that the protein component in albumin was not utilized as a nutrient by the organisms. An ether extract of fatty acid-free albumin supported a small but significant amount of growth. Analysis of the lipids in fatty acid-free albumin by gas chromatography revealed the presence of 686 microgram of fatty acid per g of albumin. Although a small amount of growth occurred when a lipid extract of albumin was present in the medium, growth stimulation was dependent in major part on the presence of undenatured albumin in the medium. Lipids, when bound to albumin, can serve as a nontoxic source of carbon and energy.

Culture Media↗
PubMed1978

Characterization of the immunoprotective antigen of ribosomal preparations from Haemophilus influenzae.

This investigation was designed to characterize the immunoprotective antigen of ribosomal preparations from Haemophilus influenzae. The ribosomes that elicited 80 to 90% protection contained 25% protein and 75% ribonucleic acid but did not contain any detectable hexoses. The immunodiffusion and hemagglutination inhibition tests also failed to demonstrate that the capsular material (polyribose phosphate) was in ribosomal preparations. Treatment of ribosomes with ribonuclease degraded 78% ribonucleic acid but did not affect the immunogenicity of such preparations. The proteolytic enzymes reduced the immunogenicity of ribosomes corresponding to the amount of protein degraded. The protection elicited by ribosomal protein extracted with 2-chloroethanol was comparable to that induced by intact ribosomes. In contrast, the low levels of protection observed by immunization with phenol-extracted ribonucleic acid were dependent on the amounts of contaminating protein. Finally, immunogenicity of ribosomal ribonucleic acid and protein was abrogated by treatment with proteolytic enzymes. These results clearly indicate that the protein associated with Haemophilus ribosomes is the major immunoprotective antigen.

Animals↗
PubMed1977

In vivo distribution of Pseudomonas aeruginosa slime glycolipoprotein: association with leukocytes.

Intraperitoneal injection of slime glycolipoprotein (GLP) from Pseudomonas aeruginosa induced leukopenia and death of mice, similar to the effect of infection with viable organisms. Differential counts established that the leukopenia was characterized by a decrease in the number of polymorphonuclear leukocytes, followed by death of mice. Mice immunized with GLP survived challenge and responded with a leukocytosis that had a substantial increase in circulating polymorphonuclear leukocytes. Leukocytes from GLP-injected mice were agglutinated by anti-GLP serum, indicating an association between GLP and leukocytes. Other results indicated that 14C-labeled GLP is deposited mainly in the liver. Normal leukocytes labeled with 51Cr were injected intravenously into mice receiving an intraperitoneal injection of GLP. As with GLP, the 51Gr-labeled leukocytes were sequestered in the liver. These results indicate that GLP enters the blood stream and becomes associated mainly with neutrophils, and that the neutrophil-GLP complex is deposited in the liver, possibly accounting for the leukopenia in mice.

Agglutination Tests↗
PubMed1977

Immunoprotective activity of ribosomes from Haemophilus influenzae.

Immunization with ribosomal preparations from Haemophilus influenzae type b elicited protective immunity in mice. Ribosomes from disrupted cells where isolated by differential centrifugation using sodium dodecyl sulfate. The washed ribosomes contained 25% protein and 75% ribonucleic acid and sedimented as a single peak on sucrose density gradient analysis with a sedimentation coefficient of 67S, using Escherichia coli ribosomes as a 70S marker. Immunodiffusion tests with antipolyribose phosphate serum showed that the ribosomes were free from capsular material. Mice immunized subcutaneously with ribosomes, with or without adjuvant, were challenged intraperitoneally with 100 to 1,000 mean lethal doses of H. influenzae type b suspended in gastric mucin. Significant protection was induced by ribosomes and was compared to that obtained after sublethal infection with live cells. The protection was greatly enhanced after incorporation of ribosomes into adjuvants. Maximum protection (90 to 95%) was observed at 1 to 2 weeks after immunization. Ribosomes from a nonencapsulated strain of H. influenzae were as immunogenic as those from the encapsulated strain, demonstrating that the capsular material is not responsible for immunogenicity of Haemophilus ribosomes.

Adjuvants, Immunologic↗
PubMedDate not supplied

Effects of home versus supervised exercise for patients with intermittent claudication.

PURPOSE: This study was performed to test the efficacy of a supervised, hospital-based exercise program compared with a home-based exercise program involving minimal supervision, for both walking ability and quality of life measures in patients with exercise-limiting intermittent leg claudication. METHODS: Twenty-one patients were assigned randomly to 12 weeks of supervised exercise or to a home-based exercise group. After 12 weeks the participants in the supervised group transitioned to a home-based program. Both groups were then reevaluated at the end of 24 weeks. The initial claudication distance (ICD) and absolute claudication distance (ACD) on progressive treadmill exercise was measured at baseline, 12 weeks, and 24 weeks. Additionally, self-reported quality of life status was evaluated using the MOS SF-36 questionnaire. RESULTS: Each group improved (P < 0.01) ACD from baseline to 12 weeks, which was sustained at the 24-week follow-up. Both groups experienced similar long-term improvements (P < 0.05) in ACD (521.5 +/- 253.4 meters to 741.9 +/- 365.6 meters for the supervised group, 532.2 +/- 263.5 meters to 715.0 +/- 394.4 meters in the home group, P not significant, between groups). The supervised group experienced a greater improvement (P < 0.01) in the ICD after 12 weeks than the home group but not at 24 weeks. The on-site group also experienced significant improvements in ICD after 24 weeks (P < 0.05). Neither group manifested an improvement in self-reported physical function or mental health as assessed by the MOS SF-36. CONCLUSION: A structured exercise program was more effective in improving the ICD over a 24-week period than a less formal, home-based program. However, if patients are screened properly and receive adequate instruction, a home-based program can be a safe, low-cost alternative providing similar long-term (24 weeks) exercise benefits in ACD.

Aged↗