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Biomedical subjects

M A Martin

Publications and source records attributed to M A Martin.

At least 271 records · Page 15Linked to original sources
PubMed1970

Sedimentation properties of simian virus 40-specific ribonucleic acid present in green monkey cells during productive infection and in mouse cells undergoing abortive infection.

The size distribution of polyribosome-associated simian virus 40 (SV40) ribonucleic acid (RNA) was examined at various times after productive infection. Eight hours after infection, virus-specific RNA was detected in the 14 to 17S region of a sucrose gradient by deoxyribonucleic acid (DNA)-RNA hybridization; RNA present in fractions sedimenting more rapidly did not react with SV40 DNA. At successively later times, SV40 RNA was detected in more rapidly sedimenting regions. By 24 hr, a portion of the SV40 RNA was detected in the 28S region, sedimenting slightly more rapidly than a MS2 RNA marker. Nuclear SV40 RNA, prepared from cells 48 hr after infection, was distributed in more rapidly sedimenting regions of the gradient, peaking at about 32 to 34S. Some nuclear virus-specific RNA could be detected in the 45 to 50S region. During the abortive infection of mouse cells, the sedimentation profile of SV40 RNA was very similar to that observed during the early phases of the lytic cycle.

Animals↗
PubMed1969

Polyoma virus gene activity during lytic infection and in transformed animal cells.

Randomly labeled RNA's from animal cells either productively infected or transformed by polyoma virus were used to measure virus DNA transcription. During lytic infection, 50 percent of polyoma virus DNA was expressed. In two different polyoma-transformed hamster cell lines, the same 20 percent of the virus genome was transcribed. About 10 percent of polyoma DNA was expressed in the one mouse transformed cell line examined.

Animals↗
PubMed1969

SV40 gene activity during lytic infection and in a series of SV40 transformed mouse cells.

Transcription of SV40 DNA was measured during lytic infection and in five SV40 transformed mouse cell lines. During productive infection, 50 per cent of viral DNA reacted with saturating amounts of lytic RNA. Varying portions of the SV40 genome were transcribed in transformed mouse cells, ranging from 15 per cent in a line which failed to yield virus, to 50 per cent in one line from which high titers of virus were obtained following cell fusion. The RNA from the SV40 transformed cell line, which saturated 50 per cent of the viral DNA, could not be distinguished from SV40 lytic RNA in reciprocal competition-hybridization experiments. These results suggest that some block or defect, subsequent to the transcription of SV40 DNA, prevents the appearance of progeny virus in this transformed 3T3 cell.

Animals↗
PubMed1969

Characteristics of the syrian hamster ribonucleic acid present in cells transformed by polyoma, simian virus 40, or adenovirus 12.

Ribonucleic acids of known specific activities were separately prepared from hamster cells transformed by polyoma, simian virus 40 (SV40), and adenovirus 12. When increasing amounts of these labeled ribonucleic acids were added to nitrocellulose filters containing immobilized (14)C-hamster deoxyribonucleic acid (DNA), about 5% of the DNA sites were saturated in each case. An additive saturation-hybridization experiment indicated that a portion of the 5% of the hamster DNA transcribed in SV40-transformed cells was also transcribed in polyoma-transformed cells. In addition, a separate region of the hamster genome was also transcribed in polyoma-transformed cells.

Adenoviridae↗
PubMedDate not supplied

Assessment of a breath collection technique and portable breath hydrogen monitor for use in cats and dogs.

Until now the use of breath hydrogen testing in companion animal gastroenterology has been limited to academic institutions because of the expense of the equipment. Recently portable breath hydrogen monitors, designed for use in paediatric gastroenterology, have been developed. They may be suitable for use in veterinary medicine as an ancillary diagnostic aid but, before widespread use can be recommended, thorough validation is required. Hydrogen breath tests were conducted in five dogs and four cats, undergoing investigations for small intestinal disease. Breath samples were taken using a closed-flow collection system and concurrently analysed with a commercially available portable breath hydrogen monitor and a previously validated breath hydrogen monitor. In cats, sample collection was troublesome and complete studies could only be performed in two individuals. Good correlation was demonstrated between the readings of both monitors (rs=0.902 and 0.935 for dogs and cats respectively; P<0.002) but agreement was poor with significant under-read from the portable monitor. Our results demonstrate that more studies on validation and the generation of a reference range would be required before the use of this portable hydrogen monitor could be recommended.

Animals↗
PubMedDate not supplied

Health-illness beliefs and practices of Haitians with HIV disease living in Boston.

The authors of this qualitative study explored the health-illness beliefs and practices of Haitians with HIV disease. The authors obtained a purposive sample of five Haitian men and four Haitian women with symptomatic HIV disease or AIDS living in Boston. Five themes were identified through content analysis of interviews and medical record review: (a) incorporation of traditional health-illness beliefs into beliefs about HIV disease; (b) A perceived need to hide HIV disease to avoid rejection, humiliation, and isolation; (c) use of spirituality to help cope with HIV disease; (d) history of limited contact with doctors prior to diagnosis of HIV disease; and (e) use of traditional healing practices for HIV disease. The findings have implications for improving cross-cultural communication between Haitians with HIV disease and their healthcare providers.

Adult↗
PubMedDate not supplied

Nursing considerations in the use of cidofovir for CMV retinitis in patients with AIDS: report of a roundtable meeting.

Cytomegalovirus (CMV) retinitis, a late complication of infection with HIV, generally leads to blindness if untreated. Although the retinal damage from CMV cannot be reversed, disease progression can be arrested with any one of three antiviral agents, which must be continued indefinitely. Intravenous ganciclovir and foscarnet, the earliest therapies, must be administered every day and require placement of an indwelling catheter. Cidofovir, a newly introduced intravenous antiviral, requires the least frequent administration; after two once-a-week induction doses, maintenance therapy is given only once every other week. However, cidofovir is potentially nephrotoxic and must be coadministered with nephroprotective probenecid and saline hydration. Careful adherence to treatment administration guidelines for cidofovir and probenecid is essential for safe administration of both drugs. Averting and managing adverse reactions to cidofovir and probenecid may present a true nursing challenge; however, with proper patient selection and appropriate use, cidofovir has the potential to greatly enhance the quality of life of a patient with CMV retinitis.

AIDS-Related Opportunistic Infections↗
PubMedDate not supplied

mRNA transcripts related to full-length endogenous retroviral DNA in human cells.

Mammalian cells contain multiple copies of endogenous type C retroviral DNA sequences. Among these sequences are complete, potentially infectious proviruses, proviral DNA that is expressed only in the form of viral antigens, retroviral segments that may contribute portions of envelope (env) genes during the generation of recombinant polytropic viruses, and many subgenomic viral DNA segments that may not be expressed at all. We have previously reported the identification and molecular cloning of type C retroviral sequences from human DNA and have shown that the partial nucleotide and deduced amino acid sequences of one of the clones obtained (lambda 51) are homologous to Moloney MuLV (MoMuLV) in the gag and pol regions. The lambda 51 clone as well as several others isolated from a human DNA library contained approximately 4.3 kilobases (kb) of retroviral sequences, were deleted in the env region, and were flanked by tandem repeats unlike the long terminal repeats (LTRs) typically found in proviral DNAs (P.E.S., in preparation). We describe here the characterization of a full-length human retroviral clone (lambda 4-1) containing LTR elements as well as a putative env region. DNA-RNA hybridization experiments reveal that human cells contain species of poly(A)+ RNA that anneal to segments of the full-length retroviral DNA clone.

Cloning, Molecular↗
PubMedDate not supplied

The HIV 'A' (sor) gene product is essential for virus infectivity.

The genome of the human immunodeficiency virus (HIV) contains several open reading frames (ORFs) not present in other viruses. The 'A' gene, also known as Q2 P'3, ORF-1(4) or sor5, partially overlaps the pol gene; its protein product has a relative molecular mass of 23,000 (Mr 23K) and is present in productively infected cells. The function of this protein is unclear; mutant viruses deleted in 'A' replicate in and kill CD4+ lymphocyte lines, but the high degree of conservation of the deduced amino-acid sequence in nine different HIV isolates (80%) and the presence of analogous genes in HIV-2 and other lentiviruses suggest that the gene function is an important one. Here we describe a mutant virus deficient in the 'A' gene which produces virion particles normally; however, the particles are approximately 1,000 times less infective than wild type. Transcomplementation experiments partially restore infectivity. The mutant virus spreads efficiently when virus-producing cells are co-cultivated with CD4+ lymphocytes, however, indicating that HIV can spread from cell to cell in a mechanism that does not require the 'A' gene product and probably does not require the production of infective virus particles.

Amino Acid Sequence↗