Biomedical subjects

L Banks

Publications and source records attributed to L Banks.

86 records · Page 5Linked to original sources

PubMed1987

Human papillomavirus type 16 DNA cooperates with activated ras in transforming primary cells.

The close association of human papillomavirus type 16 DNA with a majority of cervical carcinomas implies some role for the virus in this type of cancer. To define the transforming properties of HPV-16 DNA in vitro we have now performed transfection experiments on baby rat kidney cells using HPV-16 DNA in conjunction with an activated ras gene. We have demonstrated that a 6.6-kb DNA fragment, containing the early genes of HPV-16 under the control of Moloney murine leukaemia virus long terminal repeats (MoMuLV-LTRs), cooperates with EJ-ras in transforming these cells. Both DNAs are required and neither alone is effective. The cooperating activity appears to reside in a protein or proteins derived from the E6/E7 region of the HPV-16 genome.

Animals↗

PubMed1987

Expression of human papillomavirus type 6 and type 16 capsid proteins in bacteria and their antigenic characterization.

The L1 and L2 capsid proteins encoded by human papillomavirus types 6 and 16 (HPV-6 and HPV-16) have been synthesized in bacteria. Antisera were raised against the HPV-6 L1- and L2-beta-galactosidase fusion proteins and against an HPV-16 L1 C-terminal peptide which was 14 amino acids long. The HPV-16 L1 peptide antibodies have been shown to be highly reactive with the HPV-16 L1-beta-galactosidase protein but not against the equivalent HPV-6 L1-beta-galactosidase fusion protein. The effectiveness of these antibodies was compared with commercially available antibovine papillomavirus type 1 (BPV-1) antibodies and the results demonstrated that the anti-BPV-1 antibodies reacted well against HPV-6 L1-beta-galactosidase but not against HPV-16 L1-beta-galactosidase. In addition, the L2 portion of the HPV-6 L2-beta-galactosidase fusion protein appeared particularly immunogenic, since antibodies raised against this fusion protein were predominantly reactive with the L2 moiety. The HPV-16 L1 peptide antibodies described here will be preferred reagents for the specific detection of HPV-16 capsid antigens, which may be particularly important in early diagnosis of HPV-16 infection.

Antibodies, Viral↗

PubMed1987

Identification of human papillomavirus type 18 E6 polypeptide in cells derived from human cervical carcinomas.

We recently reported the expression of human papillomavirus type 18 (HPV-18) E6 protein in bacteria and the production of anti-E6 polyclonal antibodies. This work has now been extended with the production of a panel of monoclonal antibodies against the HPV-18 E6 protein. These antibodies demonstrate that there is little antigenic conservation in the E6 protein between HPV-16 and HPV-18, with only one antibody recognizing a cross-reactive epitope. We have used both the monoclonal and the polyclonal antibodies to look for E6 expression in a number of HPV DNA-containing cell lines. These reagents specifically detected a 16.5K mol. wt. polypeptide in cells derived from a human cervical carcinoma.

Antibodies, Monoclonal↗

PubMed1987

Alternative splicing of human p53 transcripts.

The human p53 gene is expressed in both normal and transformed human cells as a family of polypeptides. One type of heterogeneity, which results in variation in electrophoretic mobility, is found at amino acid residue 72 (Matlashewski et al, 1987). A second type of heterogeneity is described here which involves an alteration in the sequence of the open reading frame at the 5' end of the p53 mRNA. This heterogeneity is generated by alternative splicing at the acceptor site in intron 2 resulting in an altered 5' end coding region. This study represents the first description of an altered human p53 transcript arising by differential splicing.

Amino Acid Sequence↗

PubMed1986

Isolation of human-p53-specific monoclonal antibodies and their use in the studies of human p53 expression.

The isolation and construction of a complete human p53 cDNA and subsequent expression in monkey cells is described. A set of new anti-(human p53) monoclonal antibodies has also been obtained and used to show the expression of the human p53 cDNA in cos-l cells. These antibodies enable the specific detection of human p53, which is synthesised in the presence of p53 from other species. Fusion proteins of p53 with beta-galactosidase were used firstly as antigen and secondly, in conjunction with competition assays, to localise the determinants recognized by the antibodies. At least two previously unrecognized epitopes are involved and two of the antibodies are human-p53-specific. The epitopes are denaturation-resistant and the antibodies are, therefore, valuable for immunoblotting as well as immunoprecipitation and enzyme-linked immunoassay. Transfection of plasmids containing complete human p53 cDNA into monkey (cos-l) cells cause expression of human p53 recognized by the monoclonal antibodies. Control plasmids did not induce immunoreactive protein.

Animals↗

PubMed1986

Analysis of human p53 proteins and mRNA levels in normal and transformed cells.

p53 mRNA and proteins were examined in a variety of human transformed cells and in normal human foreskin fibroblast cells. Both the steady-state and translatable levels of p53 mRNA were the same in normal and transformed human cells. In vitro synthesized p53, programmed by mRNA from normal and transformed human cells, revealed that there was heterogeneity in the primary structure of p53 from these cells. Pulse labeling of cells and immunoprecipitation analysis with a panel of human reactive anti-p53 antibodies demonstrated that the types of p53 synthesized in vitro corresponded to the types made in vivo from SV80 and COLO 320 cells. No p53 was detectable by similar pulse-labeling analysis of HeLa and normal foreskin fibroblast cells. Since it was necessary to use anti-p53 sera from cancer patients to carry out much of the immunoprecipitation analysis in this study we therefore further characterised these sera to determine if they reacted with one or more than one epitope. p53-beta-galactosidase fusion proteins were synthesized in Escherichia coli and used to analyse the anti-p53 antibodies produced by cancer patients. We demonstrate that the antisera contain antibodies directed against epitopes in both the N-terminal and C-terminal regions of the p53 molecule.

Antibody Specificity↗

PubMed1986

The expression of human papillomavirus type 18 E6 protein in bacteria and the production of anti-E6 antibodies.

Human papillomavirus type 18 (HPV-18) has recently been closely linked with human malignant cervical lesions. The early region of the genome of the related bovine papillomavirus (BPV) has been shown to be important for the production of the transformed phenotype. BPV E6 has been shown to be a transforming protein. We report the primary structure of the HPV-18 E6 open reading frame and its predicted amino acid sequence. Both E6 protein and E6-beta-galactosidase fusion protein were synthesized in bacteria. Antisera were raised against the E6-beta-galactosidase fusion protein and against an E6 N-terminal peptide which was 14 amino acids long. We show that these antisera reacted on Western blots against E6 synthesized in bacteria. The HPV E6 antigen and antibodies described here will be useful in understanding HPV expression and its association with human malignancies and may also be diagnostically useful.

Amino Acid Sequence↗

PubMed1986

Familial hypopituitarism associated with an enlarged pituitary fossa and an empty sella.

We report an 8-year follow-up of three sisters born of a consanguineous marriage and who originally presented with short stature and enlarged pituitary fossa. All have shown progressive failure of anterior pituitary hormone function. In addition, the two eldest sisters were eventually found to have an empty sella while the youngest, who initially showed an enhancing intrasellar mass consistent with a tumour, later showed an empty sella. A familial pituitary tumour developing early in childhood but subsequently undergoing involution could account for these findings.

Adolescent↗

PubMed1986

Expectant management of patients with unilateral hepatic duct stricture and liver atrophy.

Three patients with postcholecystectomy unilateral hepatic duct stricture and subsequent liver atrophy were treated conservatively, with a successful outcome of up to three years follow up. A better understanding of the pathophysiological sequelae of segmental hepatic duct obstruction suggests that in such circumstances reconstructive surgery, with its attendant risks, may not invariably be necessary.

Adult↗

PubMed1985

The role of CT in the diagnosis of primary lymphedema of the lower limb.

Twelve patients with primary lymphedema of the lower limb were examined with computed tomography (CT). A characteristic "honeycomb" pattern of the subcutaneous compartment was seen in 10 of these patients. CT scans in nine other patients with swollen leg secondary to chronic venous disease or lipedema did not show this characteristic pattern. CT may be helpful in the differential diagnosis of a swollen leg, thus obviating venography or lymphangiography.

Diagnosis, Differential↗

PubMed1983

Computed tomography of the heart: initial experience.

Computed tomography (CT) provides non-invasive diagnosis of cardiac lesions by direct demonstration of the myocardium and the individual cavities of the heart. The potential role of CT scanning in the detection and quantitation of acute myocardial infarction has been previously investigated in experimental animals. Initial experience in assessing 10 patients admitted with recent infarction on biochemical and electrocardiographic evidence is reported. Intravenous infusion of iodinated contrast agents produced contrast enhancement either of the rim or diffusely through the myocardium in the area of infarct, as sited electrocardiographically. Patients with coronary artery bypass grafts and hypertrophic cardiomyopathy have also been studied by this method. Cardiac CT with intravenous administration of contrast may have an important role in the future in assessment and follow-up of ischaemic heart disease.

Cardiomyopathy, Hypertrophic↗

PubMed1983

Herpes simplex virus non-structural proteins. IV. Purification of the virus-induced deoxyribonuclease and characterization of the enzyme using monoclonal antibodies.

The alkaline nucleases induced by herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) have been purified from high salt extracts of virus-infected cells. The purification used three types of column chromatography and resulted in apparently homogeneous DNase preparations with good recovery. The enzyme from HSV-2-infected cells has been characterized. It had both exonuclease and endonuclease activity, each with an unusually high pH optimum. The enzyme had an absolute requirement for magnesium which could not be replaced by other divalent cations. Analysis of the sedimentation characteristics and electrophoretic properties of the purified enzyme indicated that it was composed of a single subunit of mol. wt. 85 000. The purified HSV-2 enzyme was used as an immunogen to prime BALB/c mice which were used to prepare monoclonal antibodies. Three monoclonal antibodies were shown by several criteria to react with the enzyme. Thus, we were able to confirm that the 85K polypeptide did indeed have nuclease activity. This polypeptide was designated ICSP 22 in earlier studies and is a major polypeptide of virus-infected cells.

Animals↗

PubMed1983

High-resolution characterization of herpes simplex virus type 1 transcripts encoding alkaline exonuclease and a 50,000-dalton protein tentatively identified as a capsid protein.

Four partially overlapping mRNAs (1.9, 2.3, 3.9, and 4.5 kilobases [kb]) were located between 0.16 and 0.19 map units on the herpes simplex virus type 1 genome. Their direction of transcription was found to be from right to left. The 2.3-kb mRNA was found to be early (beta), whereas the others were late (beta gamma). Partial sequence analysis of the DNA encoding these genes indicated that the promoter for the 2.3-kb mRNA shares structural features with other early (beta) promoters. In vitro translation of hybrid-selected mRNA indicated that among the proteins these mRNAs encode are an 82,000-dalton (d) polypeptide reactive with a monoclonal antibody against herpes simplex virus type 2 alkaline exonuclease and a 50,000-d polypeptide weakly reactive with a polyclonal antibody made against the capsid protein VP19C. Further experiments suggested that the 2.3-kb mRNA encodes the 82,000-d polypeptide, whereas one (or both) of the larger mRNAs encodes the 50,000-d protein. A novel finding was that the 1.9-kb mRNA appears to share part of the translational reading frame for alkaline exonuclease, but any polypeptide it encodes does not react with the monoclonal antibody to this enzyme.

Base Sequence↗

PubMed1975

Prolactin studies in "functionless" pituitary tumours.

Hyperprolactinaemia was found in all 17 women and in one out of six men who presented with hypogonadism and a radiologically enlarged sella turcica but no other clinical endocrine dysfunction. Some of the women also had galactorrhoea. The greater the level of hyperprolactinaemia in these 18 patients the larger their sellae turcica except in two patients with unusual features. The sella turcica was usually asymmetrically enlarged and there was rearly an upward extension of tumour, though the sella floor often showed some erosion on tomography. An oral dose of bromocriptine suppressed the hyperprolactinaemia in mose patients at the same rate as in normal post-partum women. Nine of the 18 patients with hyperprolactinaemia had low basal luteinizing hormone (LH) levels. The LH responsiveness to 100 mug of LH-releasing hormone (LHRH) was tested in 12, and eight showed subnormal values. Of eight biopsy specimens obtained four showed acidophil granules on light microscopy, and in five granules of various sizes were seen on electron microscopy.

Adult↗