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Biomedical subjects

M Levine

Publications and source records attributed to M Levine.

At least 451 records · Page 25Linked to original sources
PubMed1985

T-cell chronic lymphocytic leukaemia: anomalous cell markers, variable morphology, and marked responsiveness to pentostatin (2'-deoxycoformycin).

4 men with an unusual variant of T-cell chronic lymphocytic leukaemia are reported. The clinical features differed from the virus-associated T-cell disease reported from Japan, the Caribbean, and the southeastern United States. Cytology was pleiomorphic: cells with cerebriform nuclei resembling Sézary cells and lymphocytes with cytoplasmic granules resembling T-suppressor cells occurred in the same patients. Immunofluorescence studies with monoclonal antibodies suggested that the leukaemia cells expressed determinants of both helper- (OKT4+) and suppressor-(OKT8+) related antigens. The cells were TdT-negative. In all patients the disease was very refractory to conventional cytotoxic agents, but there was prompt and extensive response to the adenosine deaminase inhibitor pentostatin (2'-deoxycoformycin). This agent merits further study in the treatment of T-cell chronic lymphocytic leukaemia.

Adult↗
PubMed1985

Epitopes of herpes simplex virus type 1 glycoprotein gC are clustered in two distinct antigenic sites.

Epitopes of herpes simplex virus type 1 (HSV-1) strain KOS glycoprotein gC were identified by using a panel of gC-specific, virus-neutralizing monoclonal antibodies and a series of antigenic variants selected for resistance to neutralization with individual members of the antibody panel. Variants that were resistant to neutralization and expressed an antigenically altered form of gC were designated monoclonal antibody-resistant (mar) mutants. mar mutants were isolated at frequencies of 10(-3) to 10(-5), depending on the antibody used for selection. The epitopes on gC were operationally grouped into antigenic sites by evaluating the patterns of neutralization observed when a panel of 22 antibodies was tested against 22 mar mutants. A minimum of nine epitopes was identified by this process. Three epitopes were assigned to one antigenic site (I), and six were clustered in a second complex site (II) composed of three distinct subsites, IIa, IIb, and IIc. The two antigenic sites were shown to reside in physically distinct domains of the glycoprotein, by radioimmunoprecipitation of truncated forms of gC. These polypeptides lacked portions of the carboxy terminus and ranged in size from approximately one-half that of the wild-type molecule to nearly full size. Antibodies recognizing epitopes in site II immunoprecipitated the entire series of truncated polypeptides and thereby demonstrated that site II resided in the N-terminal half of gC. Antibodies reactive with site I, however, did not immunoprecipitate fragments smaller than at least two-thirds the size of the wild-type polypeptide, suggesting that site I was located in the C-terminal portion. Sites I and II were also shown to be spatially separate on the gC polypeptide by competition enzyme-linked immunosorbent assay with monoclonal antibodies representative of different site I and site II epitopes.

Animals↗
PubMed1985

Passive immune protection by herpes simplex virus-specific monoclonal antibodies and monoclonal antibody-resistant mutants altered in pathogenicity.

Virus-neutralizing monoclonal antibodies specific for 13 different genetically defined epitopes of glycoproteins gC, gB, and gD of herpes simplex virus type 1, strain KOS-321, were compared for their ability to provide passive immunity to DBA-2 mice challenged intracranially. Protection was highly specific, since individual monoclonal antibodies failed to protect against infection with monoclonal antibody-resistant (mar) mutants altered in the single epitope recognized by the injected antibody. The dose-response kinetics of passive immunity paralleled the in vitro neutralization titers for each antibody. No correlation was observed between immune protection and antibody isotype or complement-dependent in vitro neutralization titers. This suggests that virus neutralization was not the protective mechanism. In general, antibodies reactive with epitopes of gC were protective at the lowest antibody doses, antibodies specific for gB were less efficient in providing immunity, and antibodies against gD were the least effective. mar mutants with single epitope changes in gC and multiple epitope changes in gB showed highly reduced pathogenicity, requiring up to 5 X 10(6) PFU to kill 50% of infected animals. These findings indicated that antigenic variation affects virus growth and spread in the central nervous system. Thus, mutations which affect antigenic structure also can alter virus pathogenicity. The alteration of these epitopes does not, however, appreciably reduce the development of resistance to infection. Infection of mice with these mutants or inoculation of mice with UV-inactivated, mutant-infected cells before challenge rendered the animals resistant to infection with wild-type herpes simplex virus type 1.

Animals↗
PubMed1985

The pediatric population of two free-standing emergency clinics.

We studied the pediatric patient population of two free-standing emergency clinics (FECs) through an audit of medical records for 20 days randomly selected throughout 1983. We recorded the age, sex, number of visits, patient diagnoses, laboratory work, and charges. This information was compared with earlier national studies of physician practice. Of the 1062 visits audited, 27.6 percent were by patients 21 years of age or younger. This number is comparable to the percentage of office visits made to a national sample of general and family practitioners but well below the same figure for pediatricians. The pattern of FEC visits by this age group emerged as quite different from the pattern of visits to a national sample of office-based physicians by the same age group. The most frequent diagnoses for pediatric patients visiting FECs were upper respiratory infection (31.9%) and trauma related problems (28.5%). The number of laboratory diagnostic procedures ordered in FECs was lower than similar statistics for a national sample of pediatricians. Mean charges for visits in the FECs studied were $40.23.

Adolescent↗
PubMed1985

Differential effect of cimetidine on serum concentrations of carbamazepine and phenytoin.

Cimetidine is an inhibitor of drug metabolism. We studied the effects of cimetidine (1,200 mg/d) on steady-state serum concentrations of carbamazepine and phenytoin in 11 epileptic volunteers. The mean serum carbamazepine concentration was unchanged after 7 days of cimetidine treatment. Five subjects were taking phenytoin concurrently; their mean serum phenytoin concentration was significantly increased after 7 and 10 days of cimetidine treatment and returned to baseline 2 weeks after cimetidine was discontinued. Cimetidine apparently inhibits the clearance of phenytoin but not of carbamazepine in adults on chronic therapy.

Adolescent↗
PubMed1984

Herpes simplex virus thymidine kinase gene is stably maintained and expressed in cells transformed by protoplast fusion.

We examined a series of transformed cell lines resulting from transfer of the herpes simplex virus type 1 thymidine kinase gene to Ltk- cells by protoplast fusion gene transfer. We show that multiple copies of the transforming plasmid DNA, ranging from a minimum of two to greater than 20, were present in one or at most a few integration sites in each cell line. The TK+ phenotype was stable in five independent transformed cell lines after growth in nonselective medium for over a year. Transforming plasmid DNA was stable in one cell line containing from two to five copies after a year of growth in nonselective medium. In another cell line initially containing about 20 copies, the transforming DNA became rearranged soon after growth to mass culture, resulting in a decrease to two to five copies which then remained stably maintained. This suggests that TK+ transformants resulting from protoplast fusion are stable when the input DNA has integrated in a relatively low copy number.

Animals↗
PubMed1984

Human serum precipitins to oral bacteria related to dental caries.

Adults aged 20-38 years were classified by a positive (+) or negative (-) precipitating serum antibody response to D-alanyl glycerol teichoic acid (S), or an antigen from Actinomyces spp. (A). Culture filtrates of Streptococcus mutans and Actinomyces viscosus were used to detect the respective specific antibodies by immunoelectrophoresis and immunodiffusion when present in serum at a concentration of more than 0.05 mg/ml. Among subjects who had grown up in fluoridated areas, A+ subjects exhibited significantly fewer decayed, missing and filled teeth or teeth surfaces compared to A- subjects (p less than 0.02). For the whole population examined, caries severity increased with age and decreased with length of residence in a fluoridated area (p less than 0.01). When classified by A and S antibody response, only S-subjects showed a significant increase in caries score with age (p less than 0.02) and only A+S+ subjects a significant decrease in score with length of exposure to fluoridated water (p less than 0.05). It is concluded that the severity of caries in relation to age and fluoride exposure may differ in subjects with the different antibody specificities.

Actinomyces↗
PubMed1984

Recurrence of allergic bronchopulmonary aspergillosis after seven years of remission.

A staging system has been presented previously to assist in the evaluation and management of allergic bronchopulmonary aspergillosis (ABPA). One of these stages is a remission stage in which patients are free from pulmonary infiltrates. It had been uncertain whether patients with ABPA in remission were at risk for recurrences. We now present a patient in whom recurrence of ABPA developed after 7 yr of remission that demonstrates that patients with ABPA are at risk for recurrences for a prolonged period of time.

Adult↗
PubMed1984

Human DNA sequences homologous to a protein coding region conserved between homeotic genes of Drosophila.

Several human DNA sequences were isolated by virtue of homology to a highly conserved region that has been identified in a number of homeotic genes in Drosophila. Structural analysis of the human DNAs indicate that two separate and distinct regions sharing a high degree of homology with the homeo box sequences of Drosophila are separated by only 5 kb in the human genome. Sequence determination of these regions reveals that both human DNA sequences contain a region capable of coding 61 amino acids, which shares greater than 90% homology with the peptide sequences specified by the homeo box domain of Drosophila homeotic genes, Antennapedia, fushi tarazu, and Ultrabithorax. By contrast, the human DNA sequences lying outside of the 190 nucleotide homeo box region share virtually no sequence homology, either with the flanking sequences of the other human clones or with flanking regions of the known Drosophila homeotic genes.

Animals↗
PubMed1984

Purification and characterization of the serotype c antigen from Actinobacillus actinomycetemcomitans.

The serotype c antigen from Actinobacillus actinomycetemcomitans was purified with fractional ethanol precipitation of cell-free culture supernatant, sequential ion-exchange chromatography, and gel filtration chromatography. The preparation obtained demonstrated a single precipitin line in immunodiffusion, immunoelectrophoresis, and crossed immunoelectrophoresis when rabbit antisera to serotype c whole bacterial cells were used. No immunological reaction was detected with antisera to serotype c lipopolysaccharide, indicating that lipopolysaccharide was not present in the preparation. The serotype c antigen was composed of 95% carbohydrate, 2% protein, and 3.1% phosphate. Gas chromatographic analysis of the antigen obtained from growth in either complex or chemically defined media revealed that the carbohydrate constituent was composed of 84 to 90.1% mannose, 4.8 to 16% glucose, 1.9% N-acetylglucosamine, 1.4% fucose, and 0.2% galactose. The present data suggest that A. actinomycetemcomitans serotype c antigen is predominantly a mannose-containing carbohydrate suggestive of a mannan.

Actinobacillus↗
PubMed1984

D-Alanyl-substituted glycerol lipoteichoic acid in culture fluids of Streptococcus mutans strains GS-5 and BHT.

The content and D-alanyl ester complement of lipoteichoic acid from stationary-phase culture filtrates of Streptococcus mutans (strains BHT and GS-5; serotypes b and c) were determined chemically and serologically. A third less lipoteichoic acid was obtained from strain GS-5 than from strain BHT. This lipoteichoic acid had an increased mobility on immunoelectrophoresis after exposure overnight at pH 8 and a 10-fold greater content of alanine per mole of glycerol.

Alanine↗
PubMed1984

Transcriptional and genetic analyses of the herpes simplex virus type 1 genome: coordinates 0.29 to 0.45.

We have constructed a map of the genes encoded by a 23,000-nucleotide-pair region of herpes simplex virus type 1. This region, defined by the three adjacent EcoRI fragments N (map coordinates 0.298 to 0.315), F (0.315 to 0.421), and M (0.421 to 0.448), has previously been shown by genetic analysis to contain the genes for thymidine kinase, nucleocapsid protein p40, glycoprotein B, DNA-binding protein, and DNA polymerase. We report the identification and mapping of RNAs defining 13 viral genes encoded by the region 0.298 to 0.448. The transcriptional pattern shows families of overlapping messages, similar to those observed in other regions of the viral genome. We also isolated mutants representing four distinct complementation groups and physically mapped several of the mutations to regions within EcoRI fragment F by marker rescue. Mutations representing complementation groups 1-9 (glycoprotein B), 1-1 (DNA-binding protein), and 1-3 (DNA polymerase) were mapped to coordinates 0.361 to 0.368 to 0.411, and 0.411 to 0.421, respectively. A fourth previously undefined complementation group was mapped to the region between glycoprotein B and DNA-binding protein. Comparing the transcription mapping with marker rescue data suggests that the genes for glycoprotein B, DNA-binding protein, DNA polymerase, and nucleocapsid protein p40 are expressed as 3.3-, 4.2-, 4.3- or 4.2- or both, and 2.4-kilobase mRNAs, respectively.

Chromosome Mapping↗
PubMed1984

Immunogenicity of herpes simplex virus glycoproteins gC and gB and their role in protective immunity.

The relative antigenicity of the individual herpes simplex virus type 1 (KOS) glycoproteins gC and gB was analyzed in BALB/c mice by using KOS mutants altered in their ability to present these antigens on cell surface membranes during infection. The mutants employed were as follows: syn LD70 , a non-temperature-sensitive mutant defective in the synthesis of cell surface membrane gC; tsF13 , a temperature-sensitive mutant defective in the processing of the precursor form of gB to the mature cell surface form at 39 degrees C; and ts606 , an immediate early temperature-sensitive mutant defective in the production of all early and late proteins including the glycoproteins. By comparing the relative susceptibility to immunolysis of mouse 3T3 cells infected at 39 degrees C with wild-type virus, presenting the full complement of the glycoprotein antigens, gC, gB, and gD, with target cells infected with mutants presenting only subsets of these antigens, we determined that a major portion of cytolytic antibody contained in hyperimmune anti-herpes simplex virus type 1 (KOS) mouse antiserum was directed against glycoproteins gC and gB. The relative immunogenicity of wild-type and mutant virus-infected cells also was compared in BALB/c mice. Immunogen lacking the mature form of gB induced a cytolytic antibody titer comparable to that of the wild-type virus, whereas that lacking the mature form of gC showed a 70% reduction in titer. The absence of the mature cell surface forms of gB and gC in immunogen preparations resulted in a 4- to 15-fold reduction in in virus neutralizing titer. Animals immunized with ts606 -infected cells (39 degrees C) induced relatively little virus-specific cytolytic and neutralizing antibody. Analysis of the glycoprotein specificities of these antisera by radioimmunoprecipitation showed that the antigens immunoprecipitated reflected the viral plasma membrane glycoprotein profiles of the immunogens. The absence of the mature forms of gC or gB in the immunizing preparation did not appreciably affect the immunoprecipitating antibody response to other antigens. Mice immunized with wild-type and mutant virus-infected cells were tested for their resistance to intracranial and intraperitoneal challenge with the highly virulent WAL strain of herpes simplex virus type 1. Despite the observed alterations in serum virus-specific antibody induced with the individual immunogens, all animals survived an intraperitoneal challenge of 10 50% lethal doses. However, differences in the survival of animals were obtained upon intracranial challenge.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1984

Herpes simplex virus type 1 glycoprotein C-negative mutants exhibit multiple phenotypes, including secretion of truncated glycoproteins.

A virus-neutralizing monoclonal antibody specific for glycoprotein C (gC) of herpes simplex virus type 1 strain KOS was used to select a number of neutralization-resistant mutants. A total of 103 of these mutants also were resistant to neutralization by a pool of gC-specific antibodies and thus were operationally defined as gC-. Analysis of mutant-infected cell mRNA showed that a 2.7-kilobase mRNA, comparable in size to the wild-type gC mRNA, was produced by nearly all mutants. However, six mutants, gC-5, gC-13, gC-21, gC-39, gC-46, and gC-98, did not produce the normal-size gC mRNA but rather synthesized a novel 1.1-kilobase RNA species. These mutants had deletions of 1.6 kilobases in the coding sequence of the gC structural gene, which explains their gC- phenotype. Despite the production of an apparently normal mRNA by the remaining 97 mutants, only 7 mutants produced a detectable gC polypeptide. In contrast to wild-type gC, which is a membrane-bound glycoprotein with an apparent molecular weight of 130,000 (130K), five of these mutants quantitatively secreted proteins of lower molecular weight into the culture medium. These were synLD70 (101K), gC-8 (109K), gC-49 (112K), gC-53 (108K), and gC-85 (106K). The mutant gC-3 secreted a protein that was indistinguishable in molecular weight from wild-type KOS gC. Another mutant, gC-44, produced a gC protein which also was indistinguishable from wild-type gC by molecular weight and which remained cell associated. Pulse-labeling of infected cells in the presence and absence of the glycosylation inhibitor tunicamycin demonstrated that these proteins were glycosylated and provided estimates of the molecular weights of the nonglycosylated primary translation products. The smallest of these proteins was produced by synLD70 and was 48K, about two-thirds the size of the wild-type polypeptide precursor (73K). Physical mapping of the mutations in synLD70 and gC-8 by marker rescue placed these mutations in the middle third of the gC coding sequence. Mapping of the mutations in other gC- mutants, including two in which no protein product was detected, also placed these mutations within or very close to the gC gene. The biochemical and genetic data available on mutants secreting gC gene products suggest that secretion is due to the lack of a functional transmembrane anchor sequence on these mutant glycoproteins.

Animals↗
PubMed1984

Biochemical characterization of peptides from herpes simplex virus glycoprotein gC: loss of CNBr fragments from the carboxy terminus of truncated, secreted gC molecules.

A biochemical characterization of peptides from herpes simplex virus type 1 glycoprotein gC was carried out. We utilized simple micromethods, based on immunological isolation of biosynthetically radiolabeled gC, to obtain gC in pure form for biochemical study. CNBr fragments of gC were prepared, isolated, and characterized. These CNBr fragments were resolved into six peaks by chromatography on Sephacryl S-200 in 6 M guanidine hydrochloride. Only three of the CNBr fragments contained carbohydrate side chains, as judged from the incorporation of [14C]glucosamine. Radiochemical microsequence analyses were carried out on the gC molecule and on each of the CNBr fragments of gC. A comparison of this amino acid sequence data with the amino acid sequence predicted from the DNA sequence of the gC gene showed that the first 25 residues of the predicted sequence are not present in the gC molecule isolated from infected cells and allowed alignment of the CNBr fragments in the gC molecule. Glycoprotein gC was also examined from three gC mutants, synLD70, gC-8, and gC-49. These mutants lack an immunoreactive envelope form of gC but produce a secreted, truncated gC gene product. Glycoprotein gC from cells infected with any of these gC- mutants was shown to have lost more than one CNBr fragment present in the wild-type gC molecule. The missing fragments included the one containing the putative transmembrane anchor sequence. Glycoprotein gC from the gC-8 mutant was also shown, by tryptic peptide map analysis, to have lost more than five major arginine-labeled tryptic peptides arginine-labeled tryptic peptides present in the wild-type gC molecule and to have gained a lysine-labeled tryptic peptide not present in wild-type gC.

Amino Acid Sequence↗