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Biomedical subjects

J L Jacobs

Publications and source records attributed to J L Jacobs.

At least 19 recordsLinked to original sources
PubMed1989

Host and bacterial factors associated with Haemophilus influenzae type b disease in Minnesota children vaccinated with type b polysaccharide vaccine.

Host and bacterial factors were evaluated among 86 Minnesota children with Haemophilus influenzae type b disease detected by active surveillance after introduction of type b polysaccharide vaccine in the state. Children were 2-6 y of age. Thirty-three (38%) had been vaccinated. There was no significant difference between the frequency of low serum concentrations of IgM, IgA, IgG, or IgG2 in the vaccinated and nonvaccinated subjects (13% vs. 8%, P = .5). The presence of the Gm immunoglobulin allotype phenotype (1,3,17;23;5,13,21), previously associated with a lower relative risk of vaccine failure in children from other states, was associated with a fourfold decrease in the relative risk of vaccine failure in Minnesota (P less than .07). Haemophilus isolates from 58 of the children were available for clonal characterization by multilocus electrophoresis and outer membrane protein subtyping. There were no significant differences between the clone distribution of the strains causing disease in vaccinated and nonvaccinated patients, and nearly all disease-producing clones in Minnesota also are known to cause disease in other areas of the country. Thus, vaccine failure in Minnesota is infrequently associated with hypogammaglobulinemia or with infection by unusual clones of a H. influenzae type b. Also, the Gm phenotype associated with protection against vaccine failure in other areas of the USA appears to be protective in Minnesota.

Antibodies, Bacterial↗
PubMed1988

Lack of efficacy of Haemophilus b polysaccharide vaccine in Minnesota.

We evaluated the efficacy of Haemophilus b polysaccharide vaccine in children in Minnesota using a case-control study. The vaccine became available in Minnesota in August 1985. During the subsequent 28 months, 88 cases of invasive H influenzae type b disease were identified in children 24 to 71 months of age, the group targeted for vaccination. Of the 88 cases, 36 (41%) occurred in vaccinated children. Fifty-eight (33%) of 176 controls were vaccinated during a similar period. The vaccine's protective efficacy for children with any history of vaccination was -58% (95% confidence interval = -204% to 18%). The vaccine's protective efficacy for children who were most likely to be protected by vaccination was -55% (95% confidence interval = -238% to 29%). Our results indicate that vaccination with Haemophilus b polysaccharide vaccine had no effect in preventing H influenzae type b disease in Minnesota children.

Bacterial Capsules↗
PubMed1988

Extended polysialic acid chains (n greater than 55) in glycoproteins from human neuroblastoma cells.

Polysialic acid-containing glycoproteins consisting of extended chains of at least 55 sialyl residues (DP55, where DP represents degree of polymerization) are expressed on human neuroblastoma cells, CHP-134. The strategy used for detecting these unique carbohydrate structures was based on the use of two highly specific prokaryotic-derived enzyme systems and an anti-polysialosyl antibody (H.46). These probes were developed for the detection of polysialic acid on neural cell adhesion molecules (Troy, F. A., Hallenbeck, P. C., McCoy, R. D., and Vimr, E. R. (1987) Methods Enzymol. 138, 169-185). Proof for the presence of long chain multimers of sialic acid was based on two types of experiments which utilized: 1) a glycopeptide fraction of CHP-134 cells, labeled metabolically with D-[3H]GlcN and 2) a membrane fraction from CHP-134 cells which served as an exogenous acceptor of [14C] NeuNAc residues in an Escherichia coli K1 sialyltransferase assay. In vitro, this enzyme CMP-NeuNAc:poly-alpha-2,8-sialosyl sialyltransferase catalyzes the transfer of [14C]NeuNAc from CMP-[14C]NeuNAc to exogenous acceptors containing at least 3 sialyl residues. In the first series of experiments, endo-N-acetylneuraminidase (Endo-N), a bacteriophage-derived enzyme specific for hydrolyzing poly-alpha-2,8-sialosyl chains containing a minimum of 5 sialyl residues was used. Limit Endo-N digestion of the 3H-glycopeptides from the [3H] GlcN-labeled cells released short [3H]sialyl oligomers [( 3H]DP1-6) which were degraded to [3H]NeuNAc by exosialidase. Partial Endo-N digestion released a series of [3H]sialyl oligomers extending up to DP55. The longer (DP20-55) and intermediate sized (DP10-20) oligomers were isolated and converted to short oligomers ((3H]DP1-6) by retreating with Endo-N, thus confirming their identity as homo-oligomers of alpha-2,8-linked [3H]NeuNAc residues. In the second series of experiments, a membrane fraction of CHP-134 cells was radiolabeled in vitro with [14C]NeuNAc by E. coli K1 sialyltransferase. The membrane fraction had a major portion of radioactivity that was high Mr and polydisperse (Mr 100,000-250,000) as demonstrated in sodium dodecyl sulfate-polyacrylamide gels. Using Western blotting, pre-existing material of similar size was shown to react with antibody H.46.(ABSTRACT TRUNCATED AT 400 WORDS)

Cell Line↗
PubMed1988

The influence of Fluosol-DA on the occurrence of lung metastases in Lewis lung carcinoma and B16 melanoma.

The development of lung metastases from subcutaneously implanted tumors or the development of lung nodules from intravenously injected tumor cells are model systems for metastases formation. Animals bearing subcutaneous Lewis lung tumors (50-100 mm3) were treated with a single dose of Fluosol-DA followed by 1 h of breathing carbogen or maintenance in air. Their lungs were examined for metastases 25 or 40 days after tumor cell implantation. Treatment with Fluosol-DA and carbogen or air breathing reduced by almost 4-fold the number of lung metastases seen. The addition of Fluosol-DA with air or carbogen breathing to treatment of the tumor-bearing limb with 20 Gy reduced the number of lung metastases by 2-fold compared to radiation treatment alone. If Fluosol-DA was administered immediately before or up to 3 days prior to an intravenous challenge with Lewis lung tumor cells, there was a 2- to 3-fold reduction in the number of lung nodules formed. Fluosol-DA administered immediately before or up to 4 days prior to B16 melanoma cells caused a 2- to 3-fold reduction in the number of lung nodules observed. The vascular endothelial cell monolayer adhesion assay was used to test the effects of prior exposure to Fluosol-DA on the attachment of radiolabelled B16 melanoma cells in vitro. There was a trend toward increasing attachment of B16 cells to the endothelial monolayer with prior exposure to increasing concentrations of Fluosol-DA; however, this difference did not reach statistical significance.

Animals↗
PubMed1987

In vitro and in vivo activation of human mononuclear phagocytes by interferon-gamma. Studies with normal and AIDS monocytes.

To determine the potential immunotherapeutic role of interferon-gamma (IFN-gamma) as a mononuclear phagocyte-activating agent, we examined the effector cell function of peripheral blood monocytes from healthy donors and acquired immunodeficiency syndrome (AIDS) patients after either in vitro and/or in vivo treatment with recombinant (r) IFN-gamma. When assayed immediately after a 24-hr in vitro pulse with 300 U/ml, normal and AIDS monocytes behaved similarly with little augmentation of their intrinsically high levels of H2O2 release and activity against Toxoplasma gondii; in contrast, activity toward the more resistant intracellular pathogen, Leishmania donovani, was appreciably enhanced by rIFN-gamma. In addition, upon testing 4 to 6 days after in vitro pulsing, both normal and AIDS monocytes showed clear evidence of persistent activation in all three assays. The capacity of IFN-gamma to similarly activate monocytes in vivo was confirmed in all ten treated AIDS patients by examining cells before and after 24-hr infusions of 0.03 and 0.5 mg of rIFN-gamma/square meter (M2) of body surface area. For postinfusion monocytes tested after 1 day in culture, H2O2 release and antitoxoplasma activity were essentially unchanged, but antileishmanial effects were augmented. After 5 to 7 days in culture, monocytes from treated patients showed 3.2- to 5.9-fold increases in H2O2-releasing capacity and increases of 49 to 68% and 35 to 61% in intracellular activity against T. gondii and L. donovani, respectively. These results indicate that the human monocyte can be induced by rIFN-gamma to express signs of both immediate and persistent activation and suggest that, as a direct activator of mononuclear phagocytes, rIFN-gamma may also have potential as an immunotherapeutic agent for patients with intracellular infections.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Approaches to defining the mechanism of enhancement by Fluosol-DA 20% with carbogen of melphalan antitumor activity.

Fluosol-DA with carbogen (95% oxygen and 5% carbon dioxide) breathing can increase the efficacy of melphalan. Addition of Fluosol-DA to treatment with melphalan leads to a greater increase in tumor growth delay under conditions of air breathing and carbogen breathing than does the fat emulsion Intralipid. The ability of melphalan to kill tumor cells increased with dose over the range of drug examined. At the lower doses of drug there is some increase in tumor cell killing seen with the addition of carbogen breathing or Fluosol-DA and air breathing; however, at the highest dose of the drug this difference disappeared. Throughout the melphalan dosage range examined there is approximately 1 log greater tumor cell kill observed with the addition of Fluosol-DA and carbogen breathing compared to the drug treatment alone. There was no significant difference in the survival of bone marrow cells under any of the treatment conditions. Fluosol-DA itself with air or carbogen breathing produced no detectable cross-links in DNA from tumors treated in vivo. The cross-linking factors for melphalan with air or carbogen breathing and for melphalan plus Fluosol-DA and air breathing were similar; when carbogen breathing was added to the treatment combination, the cross-linking factor increased almost 3-fold. When melphalan was dissolved in Fluosol-DA, the melphalan moved quickly into the lipophilic perfluorochemical particles so that after 1 h 60% of the drug was in the perfluorochemical layer. At 24 h, 85-90% of the melphalan was sequestered in the perfluorochemical particles. The pharmacokinetics of [14C]melphalan alone, [14C]melphalan plus Fluosol-DA, and [14C]melphalan prepared in Fluosol-DA were studied in several tissues of FSaIIC fibrosarcoma-bearing mice. In general, the tissue absorption and distribution t1/2s for melphalan were shortened in the presence of Fluosol-DA (except for kidneys). Shifting the t1/2s for absorption and distribution to shorter times produces a much sharper and earlier peak in the drug exposure of the tumor. Fluosol-DA provides a relatively nontoxic means of increasing oxygen delivery to tumors and a therapeutically meaningful way of improving melphalan antitumor activity.

Animals↗
PubMed1987

Some complexes of cobalt(III) and iron(III) are radiosensitizers of hypoxic EMT6 cells.

The radiosensitizing potential in hypoxic EMT6 cells of several complexes of Co(III) and Fe(III) has been examined. The cytotoxicity of each of the agents toward oxygenated and hypoxic EMT6 cells was tested over the concentration range of 1 to 500 micron for 1-h drug exposure. There was no statistically significant difference between the cytotoxicity of these complexes toward oxygenated and hypoxic cells. Based on these findings, 100 micron was selected as the drug concentration for the initial assessment of radiosensitizing potential. The radiation survival of EMT6 cells in the presence of 100 microM drug for a series of Co(III) complexes in which the number of nitro ligands was varied showed that the hexanitro and the triamine-trinitro complexes are very effective radiosensitizers. The trans-tetrammine dinitro complex was a more effective radiosensitizer than the corresponding cis-dinitro complex. The diethylenetriamine and 1,10-phenanthroline complexes were very effective radiosensitizers, producing dose-modifying factors of 2.4. The trans-tetrammine dichloro complex was moderately effective, giving a dose-modifying factor of 1.9. On the other hand, the hexammine and triammine tricyano complexes and the trans-dinitro complex with negatively charged acetylacetonate ligands were ineffective as radiosensitizers in this system. Finally, three complexes with cyclopentadienyl ligands were examined. The ferricenium salt itself was a moderately effective radiosensitizer, giving a dose-modifying factor of 2.0. However, both the dimethylferricenium salt and the analogous cobalt complex were ineffective. The FSaIIC fibrosarcoma was used to study radiosensitizing potential in vivo. The trans-tetramminedinitro complex was administered at doses of 100, 200, or 300 mg/kg as a single ip injection 1 h prior to irradiation or as three daily ip injections. There was increasing dose modification with increasing drug dosage. With a fractionated radiation protocol in which five daily fractions of 2, 3, or 4 Gy were administered to the tumor-bearing limb with ip drug injections of 100 or 200 mg/kg given 1 h prior to irradiation, a dose-modifying effect of 1.6 was observed with 5 X 200 mg/kg of the drug.

Animals↗
PubMed1986

Intracellular distribution of a platinum-rhodamine 123 complex in cis-platinum sensitive and resistant human squamous carcinoma cell lines.

The platinum(II) tetrachlorodianion and two molecules of rhodamine-123 associate to form a neutral tight ion pair. To examine the intracellular fate of this ionic complex, the levels of uptake after a 1-hr exposure to a 100 microM concentration of each component of the complex, the complex itself and cis-diamminedichloroplatinum(II) (CDDP) were measured in SCC-25 cells. The uptake of Pt(Rh-123)2 was measured by two independent methods: fluorescence and 195mPt gamma-counting. There was excellent agreement between these two methods as to the amount of Pt(Rh-123)2 which was taken up by the cells, indicating that the Pt(Rh-123)2 is probably entering cell intact. Association with Rh-123 increased the amount of platinum which entered the cells by about 70-fold compared to CDDP and increased by about 700-fold the amount of platinum which entered the cells compared to K2PtCl4. The subcellular distributions of Pt(Rh-123)2, Rh-123, CDDP and K2PtCl4 were also examined. When measured by fluorescence or 195mPt gamma-counting, 40-54% of the Pt(Rh-123)2 was in the nuclei of the SCC-25 or SCC-25/CP cells and 27-35% was in the cytosol of the cells. There was excellent agreement between the findings of fluorescence and 195mPt gamma-counting regarding the amount of Pt(Rh-123)2 in each of the subcellular fractions immediately after incubation with the drug and over the time course of observation after drug removal, indicating that the Pt(Rh-123)2 is probably remaining largely intact intracellularly. On a per mg protein basis, there was about a 55-fold greater amount of platinum in the nuclei of the SCC-25 cells exposed to Pt(Rh-123)2 compared to cells exposed to CDDP. In the SCC-25/CP cells, there was about 258-fold greater platinum in the nuclei of cells exposed to Pt(Rh-123)2 than those exposed to CDDP because CDDP was taken up to a much lesser extent by the SCC-25/CP cells. Association of Rh-123 with potassium tetrachlorodianion forms a tight ion pair, which enters cells in relatively high amounts and is selectively concentrated in the nuclei of the cells.

Antineoplastic Agents↗
PubMed1985

Patients at risk for AIDS-related opportunistic infections. Clinical manifestations and impaired gamma interferon production.

We studied 81 men (79 homosexuals and 2 drug abusers) with persistent lymphadenopathy to determine whether those at risk for AIDS-related opportunistic infections could be identified prospectively. (Sixty-nine of 76 [91 per cent] had antibodies to human T-cell lymphotropic virus Type III [HTLV-III], and 76 of 79 [96 per cent] had abnormal T4/T8 cell ratios.) During the follow-up period (mean +/- S.E.M., 12.9 +/- 0.5 months; range, 8 to 19), infections developed in none of 38 patients with lymphadenopathy alone and in only 1 of 15 (7 per cent) with antecedent herpes zoster infection; however, 13 of 28 (46 per cent) with lymphadenopathy accompanied by constitutional symptoms or oral candidiasis or both had opportunistic infections within the follow-up period. Among the results of various T-cell assays, only antigen-stimulated lymphocyte proliferation and gamma interferon generation, which were absent or barely measurable in those in whom AIDS ultimately developed, were of prognostic value. T cells from 15 patients, 11 of whom had constitutional symptoms or thrush, failed to generate antigen-induced gamma interferon; infections developed in 10 of these 15 (67 per cent) within a mean of 8.2 months. These results suggest that patients with AIDS-related complex who are at risk for opportunistic infections within a year can be identified by correlating clinical manifestations with antigen-stimulated T-cell responses--in particular, with the production of gamma interferon.

Acquired Immunodeficiency Syndrome↗
PubMed1985

Trapezium implant arthroplasty: evaluation of a semiconstrained implant.

Twenty-five patients who presented with symptoms of disabling pain secondary to arthritis at the base of thumb had 29 arthroplasties with silicone rubber trapezium implants. Stabilization was achieved with tenodesis using a strip of abductor pollicis longus as described by Eaton. All patients had relief of pain after surgery. We examined 23 hands in 19 patients for follow-up. Average follow-up was 31 months. Assessment of functional status and measurements of prehensile capabilities showed that all patients had improved after surgery. Range of motion of the thumb was measured (radial abduction averaged 40 degrees; 80% had full opposition). Average key pinch was 8 pounds. Stability of the implant was assessed with standard posteroanterior, lateral, and stress views of the trapeziometacarpal joint. Comparisons were made with previously reported results for Eaton and Swanson trapezium implants. The tenodesis effect may provide a more stable, although possibly less mobile, CMC joint of the thumb.

Aged↗