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Biomedical subjects

G W Long

Publications and source records attributed to G W Long.

At least 55 records · Page 3Linked to original sources
PubMed1986

Cardiopulmonary involvement rare in severe Schistosoma japonicum infection.

In a prospective study, 65 consecutive patients hospitalized with Schistosoma japonicum infection were evaluated for evidence of cardiopulmonary involvement. Thirty-two patients had evidence of severe liver dysfunction while 11 patients had portal hypertension only. Of these 43 patients with hepatosplenic disease, only one patient had pulmonary hypertension. Cardiopulmonary involvement is relatively uncommon in severe S. japonicum infections.

Adolescent↗
PubMed1985

Mapping and sequence of the gene for the pseudorabies virus glycoprotein which accumulates in the medium of infected cells.

RNA from pseudorabies virus (PRV)-infected cells was translated in a reticulocyte lysate with and without the addition of dog pancreas microsomes. Upon addition of the microsomes to the translation reaction, an additional prominent protein product was observed that was not present when microsomes were omitted. The gene coding for this processed protein and its lower-molecular-weight precursor was mapped within the small unique region of the genome by hybridization of mRNA to cloned fragments of PRV DNA and translation of the selected mRNAs. A fragment of the coding region of this gene was inserted into an open reading frame cloning vector to express part of this gene as a hybrid protein in Escherichia coli. This hybrid protein was injected into mice to raise an antiserum which was found to precipitate the glycoprotein which accumulates in the medium of PRV-infected cells. This allows us to conclude that the gene for the "excreted" glycoprotein (gX) maps to the small unique region of the genome, and that the precursor of this glycoprotein is readily processed by dog pancreas microsomes. The region of the PRV genome which codes for this glycoprotein was sequenced and found to include an open reading frame coding for 498 amino acids, flanked by sequences which contain features common to eucaryotic promoters and polyadenylation signals. The predicted protein sequence includes a hydrophobic sequence at the N-terminus which could be a signal sequence, and a hydrophobic sequence followed by a hydrophilic sequence at the C-terminus.

Amino Acid Sequence↗
PubMed1984

Multidrug-resistant Serratia marcescens bacteriuria related to urologic instrumentation.

An outbreak of urinary tract infections caused by multidrug-resistant Serratia marcescens lasted for 12 months and was found to be related to urologic instrumentation. Thirty-four patients had primary infections; four had cross-infections. Only six patients had indwelling bladder catheters. The median interval between instrumentation and initial isolation of Serratia was six days. Seventy-three percent of patients were symptomatic, two were bacteremic. No common instruments, personnel, or wards were identified, and environmental cultures failed to reveal the epidemic strain of Serratia. The outbreak ended when the instrument disinfectant was changed. Serotyping was identical in nine of ten isolates. Intraspecies conjugation demonstrated resistance transfer of gentamicin, tobramycin, carbenicillin, chloramphenicol, and co-trimoxazole. The enzyme 6'-N-acetyl transferase was responsible for gentamicin-inactivation in patient isolates and a transconjugate. Although no significant spread of this multidrug-resistance plasmid to other Enterobacteriaceae occurred in the hospital, two instances of apparent in vivo transfer to other bladder organisms occurred.

Adult↗
PubMed1984

HLA antigens and malaria at San Lazaro Hospital Manila, Philippines.

Human leucocyte antigens (HLA) were used as genetic markers in an attempt to determine possible host genetic susceptibility or resistance to malarial infections. HLA-A and B typing on lymphocytes from 68 confirmed P. falciparum and 77 P. vivax cases was compared with that found in 66 control subjects with no known history of malaria. A significant deviation was observed in the distribution of HLA-B27. This phenotype was absent in the P. falciparum group although found present in the P. vivax group (10%) and the control group (11%). Also, the combination of A9(w24) and B5 was significantly higher among the P. falciparum group than that found in the P. vivax and control groups. These findings require confirmation but do suggest the possibility of genetic susceptibility and that extensive genetic studies might be worth investigating.

Disease Susceptibility↗
PubMed1982

Efficacy of purified schistosoma japonicum egg antigens for ELISA serodiagnosis of human Schistosomiasis japonica: specificity and sensitivity.

At present, there is no consensus that purified schistosome egg antigens offer any advantage in the diagnosis of schistosomiasis by enzyme linked immunosorbent assay (ELISA). Previously, we demonstrated by multiple techniques that the major serologic antigens in Schistosoma japonicum soluble egg antigen (SEA) are glycoproteins, and that the glycoproteins with highest specificity and sensitivity are hydrophobes. We therefore tested these materials for their specificity, sensitivity and cost effectiveness in the ELISA. In this study we used five SEA fractions that varied in their purity and antigenicity. The order of immunologic specific activity in the ELISA, measured by titration of a standard sera pool, was: hydrophobic glycoproteins (highest), crude SEA glycoproteins, hydrophilic glycoproteins, crude SEA, and SEA proteins (lowest). Complexity (purity) of these materials were (in rank order), hydrophilic glycoproteins (purest), hydrophobic glycoproteins, crude glycoproteins, SEA proteins, and crude SEA (most complex). Epidemiologic sensitivity in the ELISA was tested on limited but well characterized populations. At high antigen coating concentration (0.5 microgram/well), the only antigen fraction with poor sensitivity was SEA proteins. There was little difference in epidemiologic sensitivity between the purer fractions with highest immunologic sensitivity (hydrophobic glycoproteins and crude SEA glycoproteins) and the crude SEA which possesses intermediate immunologic sensitivity. Differences in epidemiologic sensitivity were most pronounced when wells were coated at an antigen concentration (0.1 microgram/well) where crude SEA began to fail. Specificity for all preparations, assessed by reactivity with sera from patients with other trematode infections and with cestode and nematode infections, was excellent. The clinical sensitivity of the ELISA employing crude S. japonicum SEA is so high, and the specificity so good, that the increased immunologic sensitivity of partially purified antigens had little effect on epidemiologic sensitivity. This is not true for the S. mansoni ELISA where crude antigens had inferior sensitivity and specificity.

Antibodies↗
PubMed1981

Characterization of the glycoprotein antigens which mediate the Schistosoma japonicum circumoval precipitin reaction.

The circumoval precipitin test is a serological test used for diagnosis of schistosomiasis japonica. Soluble egg antigens of Schistosoma japonicum block the formation of the circumoval precipitin by serum from infected humans. Consequently, circumoval precipitin inhibition was used to monitor purification of the soluble egg antigens of S. japonicum. Crude egg antigens were separated into protein and glycoprotein fractions by lectin chromatography on concanavalin A Sepharose. The glycoprotein fraction produced two intense precipitin lines upon immunodiffusion analysis with human chronic infection sera. The protein fraction produced two faint precipitin lines which did not cross-react with those of the glycoprotein fraction. The glycoprotein fraction contained 90% of the circumoval precipitin inhibitory activity. Isoelectric focusing of (125)I-labeled concanavalin A Sepharose fractions revealed at least four groups of potential S. japonicum antigens, termed JAG I, II, and III, and a JAG IV complex. These had isoelectric points ranging from 3.2 to 6.7. In these respects, the S. japonicum egg antigen glycoproteins are similar to those of Schistosoma mansoni. The glycoproteins were further separated by diethylaminoethyl ion-exchange chromatography. On immunodiffusion analysis it was found that one of the strong Ouchterlony precipitin lines was associated with glycoproteins that did not adsorb to diethyl-aminoethyl columns, whereas the second Ouchterlony precipitin was heterodisperse, being present in the first, second, and third of the four peaks eluted from the diethylaminoethyl column. Immunoelectrophoresis of the diethylaminoethyl fractions demonstrated that the antigen present in highest concentration in soluble egg antigen glycoproteins, JAG II, was extremely heterodisperse in its behavior on diethylaminoethyl columns. This is unlike the S. mansoni antigens which can be easily separated by diethylaminoethyl ion-exchange chromatography.

Animals↗
PubMed1981

Fractionation of Schistosoma japonicum soluble egg antigen glycoproteins by hydrophobic interaction chromatography.

We are currently studying the soluble egg antigens of Schistosoma japonicum in an attempt to determine which antigens are potent immunogens. Previously, we demonstrated by Ouchterlony immunodiffusion and inhibition of the circumoval precipitin test that the glycoprotein fraction of soluble egg antigens contains the antigens which are most immunogenic in natural infections. The soluble egg antigen glycoproteins have now been further fractionated via hydrophobic interaction chromatography on phenyl Sepharose. We found that there were at least two antigens involved in the circumoval precipitin reaction. Both the hydrophilic antigen which we call japonicum antigen glycoprotein II (JAG II) and a mixture of hydrophobic antigens (JAG III and the JAG IV complex) were capable of causing a 50% inhibition of the COP reaction around S. japonicum eggs. JAG II was not a major serological antigen of S. japonicum since it gave only a weak precipitin line upon Ouchterlony immunodiffusion analysis with pooled sera from Filipino patients with chronic S. japonicum infections. Hydrophobic interaction chromatography yielded preparations which were sufficiently pure for use in radioimmunoassays. By radioimmunoassay, the best antigens among the glycoproteins were moderately hydrophobic JAG III and the JAG IV complex. They had large amounts of antibody directed toward them in patients with schistosomiasis japonica and exhibited little reactivity with S. mansoni. The hydrophilic glycoproteins JAG I and II were poor immunogens and extensively cross-reacted with S. mansoni. This cross-reactivity means that diagnostic tests with crude soluble egg antigens would run the risk of potential false-negative results in patients with other trematode infections.

Animals↗
PubMed1980

Analysis of the immunoglobulins responsible for the circumoval precipitation reaction.

Two morphologically distinct types of circumoval precipitates (COP) have been observed in human Schistosoma japonicum infections. An elongated segmented COP occurs in chronic human infections. An unsegmented "reaction of recent infection" (RRI) occurs in serum from humans with recently acquired infections and is morphologically similar to the reaction observed in the sera of mice infected with S. japonicum. Sera from infected mice and humans were separated by G-200 chromatography to determine whether the unsegmented "RRI" was due to IgM antibody and the segmented COP reaction due to IgG. There was an elevation of the 19S fraction of sera of mice with 10 and 16 week infections. In addition, the murine 7S fraction was elevated in the 16 week infections. The COP activity was confined to the 7S fraction in the murine sera. Sera from Philippine patients which produced reactions of recent infection (acute sera), segmented COP reactions (chronic sera), and mixed reactions (believed to be from a transition stage between acute and chronic schistosomiasis) were tested. All human sera had elevation of both the 19S and 7S fractions of the acute serum. However, COP-reactive antibodies were confined to the 7S fraction of sera from the transition stage and acute stage infections. The results suggest that although IgM antibodies do in certain cases participate in the COP and produce reactions of recent infection, antibody class is not responsible for the different morphology of this reaction.

Animals↗
PubMed1978

Localization of genetic control in mice over response to liver-specific F antigen.

Antibody production to the liver-specific F antigen was tested in recombinant strains of mice of different H-2 types to determine whether a histocompatibility-linked immune response (Ir) gene controlled responsiveness to this antigen. Responseiveness was found to be controlled by an Ir gene located in the K end (K and/or I-A subregions) of the H-2 complex.

Animals↗
PubMed1970

Experience with electron microscopy in the differential diagnosis of smallpox.

The usefulness of negative-contrast electron microscopy in the rapid differential diagnosis of poxvirus and herpesvirus exanthems is described in this study of 301 specimens from patients with vesicular exanthematous diseases. Specimens from patients with smallpox, various forms of vaccination complications, varicella, zoster (shingles), and herpes simplex are included in this evaluation. Electron microscopy, when applied to the study of lesion material, was found to be more sensitive than the classical techniques of virus isolation in the diagnosis of both poxvirus and herpes/varicella virus infections. However, since specific identification of a virus within a group cannot be made morphologically by electron microscopy, it is recommended that both electron microscopy and virus isolation methods be employed for the routine differential diagnosis of vesicular exanthematous diseases in the reference diagnostic laboratory.

Animals↗
PubMedDate not supplied

Reversal of drug-resistant falciparum malaria by calcium antagonists: potential for host cell toxicity.

Agents capable of reversing multidrug resistance (mdr) in falciparum malaria were investigated for potentiation of chloroquine accumulation and toxicity in a cell culture system. Verapamil, its analog RO11-2933, and desipramine caused a dose-dependent increase in the accumulation of chloroquine (CQ) within human and mouse hepatocytes but not human lung cells. Only those cells in which drug accumulation was enhanced by reversing agents reacted positively for P-glycoprotein (PgP)--the putative mediator of the enhanced drug efflux characteristic of mdr. Clinically achievable concentrations of verapamil (0.4 microM) and desipramine (1 microM) increased CQ accumulation within primary mouse hepatocytes by more than 50%. A well-differentiated normal human cell line (Hep-G2) was killed in media containing a combination of supraphysiological concentrations of CQ and verapamil but survived the same concentrations of either drug alone. Reversing agents may block PgP-mediated drug export from normal tissues as well as from MDR cells. Iatrogenic toxicity resulting from this accumulation of potentially toxic drugs such as CQ within normal cells could complicate the reversal of mdr in vivo.

ATP Binding Cassette Transporter, Subfamily B, Mem↗