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Biomedical subjects

M J Levin

Publications and source records attributed to M J Levin.

At least 127 records · Page 7Linked to original sources
PubMed1989

Comparison of intramuscular recombinant alpha interferon (rIFN-2A) with topical acyclovir for the treatment of first-episode herpes genitalis and prevention of recurrences.

Intramuscular recombinant alpha interferon (rIFN-2A; 9 million IU given for 5 days during a 9-day treatment period) was compared with topical acyclovir in a double-blind, placebo-controlled trial for the treatment of first-episode genital herpes simplex virus (HSV) infection and for subsequent alteration of the frequency of recurrences. rIFN-2A (within 96 h of onset of the first episode) was not superior to topical acyclovir in a well-matched group of 105 patients. The early use of rIFN-2A also did not alter the frequency or severity of genital HSV recurrences within either the first or second 6 months following therapy. Separate analyses by HSV type and by type of infection (primary versus nonprimary) did not change this conclusion. Furthermore, there was significant toxicity associated with rIFN-2A therapy. rIFN-2A is not indicated for the treatment of genital HSV infections.

Acyclovir↗
PubMed1989

Identification of major Trypanosoma cruzi antigenic determinants in chronic Chagas' heart disease.

To identify Trypanosoma cruzi target antigens in overt Chagas' heart disease, a parasite lambda gt11 cDNA library was screened with the serum of a patient with a severe chagasic heart involvement (JL). Using a phage dot array immunoassay, 5 highly antigenic clones, JL1, JL5, JL7, JL8, and JL9, were probed with sera from clinically characterized T. cruzi infected subjects. The correlation of cloned T. cruzi antigen recognition with the clinical status of the subjects led to the identification of a recombinant antigen, JL5, that reacted predominantly with sera from patients with Chagas' heart disease. The antigenic determinant of the JL5 recombinant was a small 35 amino acid peptide. The nucleotide and the deduced amino acid sequence, together with other experimental data, allowed identification as the C-terminal portion of a T. cruzi P ribosomal protein. The C-terminal undecapeptide in JL5, EDDDMGFGLFD, was highly homologous to the same region of the human P protein SD(D/E)DMGFGLFD. The latter sequence has been identified as the P protein epitope in systemic lupus erythematosus (SLE). Positive SLE sera reacted with the JL5 recombinant phage, suggesting that the T. cruzi P protein might induce antibodies with a similar specificity to that of P antibodies in SLE.

Adult↗
PubMed1989

Inhibition of varicella-zoster virus in vitro by human peripheral blood mononuclear cells.

A functional in vitro assay of cell-mediated immunity to varicella-zoster virus (VZV) is described. This procedure uses an enzyme-linked immunosorbent assay (ELISA) to measure the inhibitory effect of human peripheral blood mononuclear cells on VZV antigen production by VZV-infected cell monolayers. When mononuclear cells from VZV-immune, tetanus-immune donors were stimulated with either VZV antigen or tetanus toxoid they reduced VZV antigen production. In contrast, mononuclear cells from VZV-nonimmune, tetanus-immune donors reduced VZV antigen only when stimulated with tetanus toxoid, but not when stimulated with VZV antigen. Cell-free supernatants recovered from the VZV inhibition assays contained the anti-VZV activity. The magnitude of the anti-VZV activity of the supernatants equalled the inhibition observed when the stimulated mononuclear cells were added to the VZV-infected monolayers. Treatment of either mononuclear cells or supernatants with anti-interferon gamma antibody indicated that their VZV inhibitory capability was largely due to the production of interferon gamma by stimulated mononuclear cells.

Adult↗
PubMed1989

Antiviral susceptibilities of herpes simplex virus isolates from infants with recurrent mucocutaneous lesions after neonatal infection.

Recurrent mucocutaneous lesions occur in many infants after completion of antiviral therapy of neonatal herpes simplex virus (HSV) infection. To determine whether these recurrences were caused by viruses that had become resistant to acyclovir or vidarabine, we tested the antiviral susceptibilities of 22 pretherapy and 32 posttherapy HSV isolates from 22 infants younger than 3 months of age. Sixteen had been treated with acyclovir and six with vidarabine. Antiviral susceptibilities were measured by an enzyme-linked immunosorbent assay and are expressed as the 50% inhibitory dose. All HSV isolates had a 50% inhibitory dose for acyclovir of less than 1.0 micrograms/ml. The mean vidarabine 50% inhibitory dose was 11.4 micrograms/ml for pretherapy isolates and 8.9 micrograms/ml for posttherapy isolates. Antiviral therapy did not select for recurrences with HSV resistant to acyclovir or vidarabine.

Antiviral Agents↗
PubMed1988

Intracellular detection of sense and antisense enteroviral RNA by in situ hybridization.

We prepared sense (S) and anti-sense (AS) 3H-labelled single-stranded RNA probes by polymerase-directed in vitro transcription of a coxsackievirus B3-derived cDNA fragment cloned in the PGEM2 plasmid vector. The probes detected, by in situ hybridization, both S and AS forms of viral RNA in the cytoplasm of coxsackievirus-infected tissue culture cells. More S (genomic and messenger) RNA was present than AS (negative and replicative intermediate) RNA. We confirmed and quantitated this observation with slot-blot hybridization of lysates of infected cells in which the ratio of detectable S to AS RNA was 40:1. The selective detection and localization of both forms of RNA in infected cells with sensitive and specific bi-directional probes advances the applicability of in situ hybridization to the study of viral pathogenesis.

Cell Line↗
PubMed1988

Development and application of RNA probes for the study of picornaviruses.

Single-stranded RNA probes were developed from cloned cDNA fragments derived from four picornaviruses; poliovirus type 1, coxsackievirus B3, ECHOvirus 9 and Theiler's murine encephalomyelitis virus. In comparative testing with a nick-translated cDNA probe, the RNA probe was found to be 10-100-fold more sensitive. Hybridization conditions were optimized for RNA probes to picornavirus targets. Longer hybridization times gave an improved signal, as did a temperature of 50 degrees C. Formamide concentration had little effect on signal strength. A crude transcription mix performed as well or better as a probe than did more purified preparations of RNA. Finally, a combination of the three probes derived from human picornaviruses detected all 16 serotypes of human enteroviruses tested. Used individually, the four probes detected different spectra of animal and human picornaviruses, shedding more light on the interrelationships among these pathogens.

DNA↗
PubMed1988

Neonatal rotavirus-associated necrotizing enterocolitis: case control study and prospective surveillance during an outbreak.

After the death of a premature infant from rotavirus-associated necrotizing enterocolitis, we instituted prospective surveillance for this disease in our neonatal intensive care unit. During the 4-month study period an additional six cases of necrotizing enterocolitis and eight cases of hemorrhagic gastroenteritis occurred. Rotavirus infection was documented in 11 of these 15 symptomatic infants, in comparison with only eight rotavirus infections in 147 asymptomatic or minimally symptomatic babies (P less than 0.0001). Stools from 110 nursery personnel tested during the outbreak did not contain rotavirus. However, 12 of 59 staff members had serum IgM antibody against rotavirus, suggesting recent infection. In a case-control study we compared babies with severe gastrointestinal illness with a control group randomly selected from asymptomatic babies in the nursery during the time of the outbreak. Univariate analysis found six categorical variables and nine continuous variables that were significantly associated with disease. Multivariate logistic regression analysis, however, found only birth weight (P less than 0.0001), rotavirus infection (P less than 0.0001), and age at time of first nonwater feeding (P less than 0.02) to be associated with gastrointestinal illness. This study provides further evidence for the role of infection in some cases of neonatal necrotizing enterocolitis and hemorrhagic gastroenteritis.

Colorado↗
PubMed1988

Lack of correlation between infection with reovirus 3 and extrahepatic biliary atresia or neonatal hepatitis.

Infection with reovirus 3 (Reo-3) has been suggested as the cause of extrahepatic biliary atresia and idiopathic neonatal hepatitis, but confirmation has been lacking. Therefore we have searched for a specific anti-Reo-3 antibody response in the sera of patients with biliary atresia or neonatal hepatitis and for Reo-3 antigens in their hepatobiliary tissues. Sera from 23 infants with extrahepatic biliary atresia, 12 with neonatal hepatitis, 30 age-matched control patients with other liver diseases, and 55 control patients without liver disease were tested by an enzyme-linked immunosorbent assay for total (IgA, IgG, and IgM) anti-Reo-3 antibodies; sera of infants younger than 6 months of age were tested also for IgM anti-Reo-3 antibodies alone. There was no difference between either total or IgM anti-Reo-3 antibody levels in infants with extrahepatic biliary atresia or neonatal hepatitis and levels in control infants. Reo-3 antigens were not detected in the hepatobiliary tissues of 19 infants (18 with biliary atresia, one with neonatal hepatitis) by an immunoperoxidase method that readily demonstrated Reo-3 in control infected HEp-G2 cells. Our data do not support a relationship between neonatal liver diseases and infection with Reo-3.

Antigens, Viral↗
PubMed1988

Nonisotopic oligomeric probes for the human enteroviruses.

Oligonucleotide probes were prepared from highly conserved regions of human enteroviral genomes. These reagents were labeled with either 32P or alkaline phosphatase and were successfully used in blot assays to detect a wide variety of human enteroviruses, proving the potential utility of oligomeric sequences as pan-enteroviral probes. The availability of nonisotopic probes will ultimately make a hybridization assay for enteroviruses easier, shorter, and more adaptable for routine diagnostic laboratories.

Base Sequence↗
PubMed1987

Transferrin gene expression in choroid plexus of the adult rat brain.

Transferrin immunoreactivity and transferrin messenger RNA (mRNA) were recently found to be present in oligodendrocytes of the adult rat brain by using immunohistochemistry and in situ hybridization procedure. The present study demonstrates, in the same way, that epithelial cells of the choroid plexus also contain transferrin together with transferrin mRNA. Choroid plexus of the lateral and the third ventricle are rich in transferrin mRNA, while choroid plexus of the fourth ventricle contain few if any transferrin mRNA. These results demonstrate that epithelial cells of the choroid plexus as well as oligodendrocytes express the transferrin gene in the adult rat brain.

Animals↗
PubMed1987

Complete structure of the human transferrin gene. Comparison with analogous chicken gene and human pseudogene.

The complete structure of the human transferrin gene is presented. This gene has a total size of about 33.5 kb and is organized in 17 exons separated by 16 introns. The chicken ovotransferrin gene has a size of 10.5 kb and is also organized in 17 exons and 16 introns. The analysis of the structure of the two genes confirm, at the gene level, that transferrins originated by a gene duplication phenomenon. Finally, the existence of a new member of the transferrin family, a human transferrin non-processed pseudogene is demonstrated.

Amino Acid Sequence↗
PubMed1987

RNA target loss during solid phase hybridization of body fluids--a quantitative study.

Recent applications of nucleic acid hybridization to the diagnosis of viral infections are limited by the sensitivity of the assay system and, hence, by the amount of target viral nucleic acid in the specimen. In the case of single-stranded RNA viruses, RNase activity in body fluids poses a potential obstacle to optimizing sensitivity. We added radioactively labelled, purified, single-stranded enteroviral RNA to various body fluids and noted significant loss of this 'target' RNA during the course of routine hybridization procedures. We confirmed that RNase activity was responsible for much of the target loss. Further characterization of the RNase activity found it to be rapidly acting (less than 15 s), concentrated (equally active at 10-fold dilution of body fluid) and potent--resulting in RNA breakdown products too small to be retained by any of six commercially available membrane filters. The RNase was active only in solution and was effectively inhibited by treatment of the body fluid with inhibitors prior to contact of the fluid with RNA. In contrast, when RNA within virions was added to body fluids, it was largely retained by membrane filters during the hybridization procedure. We conclude that detection of single-stranded RNA viruses in body fluids will depend upon the quantity of intact virions in the specimen. RNase inhibitors should be immediately added to body fluid specimens after collection to minimize the loss of RNA which will occur if virions are disrupted in transport and handling of the specimen.

Amniotic Fluid↗
PubMed1987

Varicella zoster antibody testing in the care of pregnant women exposed to varicella.

Appropriate use of varicella zoster immunoglobulin to prevent or ameliorate maternal or perinatal infection depends on accurate identification of varicella-susceptible women. Detection of fluorescent antibody to varicella zoster virus membrane antigen is an available means for identifying women exposed to varicella who are at risk for infection. During a 5 1/2-year period, 37 pregnant women who had been exposed to varicella and who had a negative or indeterminate history of prior varicella were tested for the presence of varicella zoster virus membrane antigen. Among the 17 women with a negative history, 12 (71%) had a positive test result and five (29%) had a negative test result. Among 20 women with undeterminant histories, 18 (90%) were immune and two (10%) were susceptible. Three additional women who were tested despite a history of varicella had positive varicella zoster virus membrane antigen test results. Overall, 81% of patients with a negative or uncertain history of varicella had serologic evidence of past varicella. One of six untreated seronegative women and one weakly positive woman developed disease. There was no instance of congenital varicella. Expeditious determination of varicella zoster virus membrane antigen or equivalent anti-varicella antibody status in pregnant women exposed to varicella appears to be a rapid, satisfactory method for determining who should promptly receive varicella zoster immunoglobulin passive immunization.

Antigens, Surface↗
PubMed1987

Pharmacokinetics of acyclovir suspension in infants and children.

Eighteen children from 3 weeks to 6.9 years of age were given an oral acyclovir suspension for herpes simplex or varicella-zoster virus infections. Thirteen patients who were 6 months to 6.9 years old received 600 mg/m2 per dose, and three infants and two children less than 2 years old were given 300 mg/m2 per dose. The drug was given four times a day, except to one infant who was treated with three doses a day. Among the 13 children who received the 600-mg/m2 dose, the maximum concentration in plasma (Cmax) was 0.99 +/- 0.38 microgram/ml (mean +/- standard deviation), the time to maximum concentration (Tmax) was 3.0 +/- 0.86 h, the area under the curve (AUC) was 5.56 +/- 2.17 micrograms.h/ml, and the elimination half-life (t1/2) was 2.59 +/- 0.78 h. The three infants less than 2 months of age who received the 300-mg/m2 dose had a Cmax of 1.88 +/- 1.11 micrograms/ml, a Tmax of 4.10 +/- 0.48 h, an AUC of 6.54 +/- 4.32 micrograms.h/ml, and a t1/2 of 3.26 +/- 0.33 h. The acyclovir suspension was well tolerated by young children. No adverse effects requiring discontinuation of the drug occurred.

Acyclovir↗
PubMed1987

Rapid herpes simplex virus susceptibility testing using an enzyme-linked immunosorbent assay performed in situ on fixed virus-infected monolayers.

An enzyme-linked immunosorbent assay was performed directly on fixed, virus-infected cell monolayers to rapidly determine the susceptibility of herpes simplex virus to antiviral drugs. Susceptibility determinations by this method correlated well with those obtained by plaque reduction assay and avoided some of the drawbacks of other methods currently available.

Acyclovir↗
PubMed1987

Processing and presentation of cell-associated varicella-zoster virus antigens by human monocytes.

To determine whether viral antigens associated with infected cells were processed for presentation to T cells, we cultured human blood mononuclear cells (MNC) from varicella-zoster virus (VZV) immune donors with VZV-infected fibroblasts of known HLA type which had been fixed in 0.05% glutaraldehyde. After 7-8 days of culture thymidine uptake by T4+ cells exceeded that of T8+ cells. Stimulated cells were depleted of adherent cells and restimulated with VZV-infected fibroblasts from donors matched or unmatched with the responder for HLA type in the presence or absence of fresh adherent cells. Proliferation of the VZV-specific blasts required the presence of adherent cells matched with the responder lymphocytes for HLA-DR; conversely, the VZV specific response was not restricted by the MHC of the fibroblasts used in the restimulation assay. Preincubation of the adherent cells with chloroquine inhibited the proliferative response in a dose-dependent manner. These results suggest that VZV antigens on infected cells may be processed by monocytes for presentation to T cells.

Adult↗