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Biomedical subjects

A Roman

Publications and source records attributed to A Roman.

At least 19 recordsLinked to original sources
PubMed1992

Mutagenesis of human papillomavirus types 6 and 16 E7 open reading frames alters the electrophoretic mobility of the expressed proteins.

The E7 open reading frames of human papillomavirus type 6 (HPV-6) and HPV-16 encode proteins consisting of 98 amino acids that are quite similar in sequence yet different in electrophoretic mobility. Moreover, these proteins vary strikingly in oncogenicity. To investigate the molecular basis of the differences in structure and function, site-directed mutagenesis was used to exchange non-conserved amino acid residues between the two proteins. The mutated coding regions were expressed as fusion proteins in Escherichia coli and identified by Western blotting. Comparative analysis of the affinity-purified mutated E7 fusion proteins in polyacrylamide slab mini-gels in the presence of SDS and 2-mercaptoethanol revealed altered electrophoretic mobilities. This analysis suggests that the aspartic acid at residue 4 (Asp 4) contributes to the characteristic aberrant migration of the HPV-16 E7 protein in SDS-polyacrylamide gels.

Amino Acid Sequence↗
PubMed1991

Relative enhancer activity and transforming potential of authentic human papillomavirus type 6 genomes from benign and malignant lesions.

Human papillomavirus type 6 (HPV-6) is predominantly associated with benign genital warts whereas HPV-16 and HPV-18 are detected predominantly in carcinomas of the lower genital tract; HPV-6 is found rarely in such carcinomas. Experiments were designed to discriminate between two hypotheses concerning the role of HPV-6 in the genesis of a genital tract carcinoma: (i) the HPV-6 in the carcinoma (HPV6-T70) differs genetically from HPV-6 in a benign lesion (HPV6-W50), giving HPV6-T70 properties similar to those of HPV-16/18: (ii) HPV6-T70 and HPV6-W50 have similar biological activity, suggesting that the role of HPV-6 in oncogenesis is different from that of HPV-16/18. Restriction enzyme digestion and DNA sequence determination established that HPV6-T70 differs from HPV6-W50 in the upstream regulatory region (URR) but not in the proteins encoded by open reading frames (ORFs) E5, E6 or E7, ORFs implicated in oncogenesis. To determine whether the difference in the URR sequence could alter the level of expression of viral genes, the URRs were cloned into the enhancerless plasmid pSVEcat. Analysis of chloramphenicol acetyltransferase activity after transfection into HeLa and Vero cells showed that the URRs had comparable enhancer activity. Cotransfection of baby rat kidney (BRK) cells with HPV6-T70 and an activated ras gene indicated that, in contrast to HPV-16 and HPV-18, this HPV-6 genome could not cooperate with ras to transform BRK cells. The data suggest that HPV6-T70 and HPV6-W50 have similar enhancer activity and transforming potential.

Animals↗
PubMed1991

Analysis of invasive squamous cell carcinoma of the vulva and vulvar intraepithelial neoplasia for the presence of human papillomavirus DNA.

We have analyzed a number of invasive squamous cell carcinomas for the presence of human papillomavirus (HPV) DNA using dot blot and Southern blot analysis. Seven of 31 samples (23%) were positive by dot blot and/or Southern blot analysis. In contrast, six of 11 (55%) of vulvar intraepithelial neoplasias contained HPV DNA by dot blot and/or Southern blot hybridization. Less than 50% of the invasive vulvar carcinomas contained detectable HPV DNA. The average age at onset of vulvar carcinoma is higher than that for cervical carcinoma (in which HPV DNA is detected in over 80% of cases). Therefore, the role of HPV in the genesis of vulvar carcinoma may be different from the role of HPV in the genesis of cervical carcinoma.

Adult↗
PubMed1990

Dobutamine administration in septic shock: addition to a standard protocol.

Dobutamine administration has been shown to increase oxygen delivery in various conditions, but there are little data to document its effects in septic shock. We investigated the effects of dobutamine infusion at a rate of 5 micrograms/kg.min in 18 patients (mean 60 +/- 16 yr) with septic shock initially characterized by hypotension, oliguria, and hyperlactatemia in the presence of a documented source of sepsis. Early resuscitation had consisted of fluid administration and vasopressors when required. When added to this standard regimen, dobutamine had no significant effect on mean arterial pressure (MAP) (from 71 +/- 12 to 73 +/- 13 mm Hg), but markedly increased cardiac index (from 3.0 +/- 0.7 to 3.9 +/- 1.0 L/min.m2, p less than .001), stroke index (from 32 +/- 8 to 37 +/- 9 ml/m2, p less than .001) and oxygen transport (from 410 +/- 105 to 530 +/- 146 ml/min.m2, p less than .001). Oxygen consumption (VO2) increased concurrently (from 137 +/- 42 to 162 +/- 66 ml/min.m2, p less than .002). MAP increased (from 68 +/- 9 to 76 +/- 11 mm Hg) in 12 patients and decreased moderately (from 76 +/- 18 to 69 +/- 17 mm Hg) in six patients. The two subgroups of patients had similar hemodynamic profiles before the dobutamine infusion, but vasopressor therapy was already used in one of the 12 patients in the first subgroup and in three of the six patients in the second subgroup (p less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Oxygen uptake/supply dependency. Effects of short-term dobutamine infusion.

The present study explored the possibility of using a short-term dobutamine infusion to disclose oxygen uptake/supply dependency. The effects of a standard dose of 5 micrograms/kg/min of dobutamine on oxygen-derived variables were studied in 73 acutely ill patients with heart failure (n = 24) or sepsis (n = 49). In each group, patients were separated according to their blood lactate concentrations (either above or below 2 mEq/L). In all patient groups, dobutamine resulted in significant increases in cardiac output and oxygen transport. However, oxygen consumption increased significantly only in patients with elevated blood lactate levels (cardiac failure: from 108 +/- 26 to 131 +/- 25 ml/min/M2, n = 8, p less than 0.01; sepsis: from 139 +/- 44 to 167 +/- 68 ml/min/M2, n = 16, p less than 0.01) and not in the other patients (heart failure: from 121 +/- 29 to 115 +/- 31 ml/min/M2, n = 28, NS; sepsis: from 158 +/- 39 to 166 +/- 45 ml/min/M2, n = 21, NS). These data, therefore, indicate that dobutamine at the dose used does not increase oxygen consumption in critically ill patients unless there is coexistent tissue hypoxia reflected by increased blood lactate levels. A short-term dobutamine infusion can be used to disclose an oxygen uptake/supply dependency phenomenon.

Acidosis, Lactic↗
PubMed1989

Calbindin-D28 in mammalian brain, retina, and endocrine pancreas: immunohistochemical comparison with calretinin.

Calbindin 28K and calretinin are very similar calcium binding proteins which are both present in the central nervous system (CNS). They respectively bind 4 and 5 Ca++ ions. We have compared by immunohistochemistry and in situ hybridization their localisation in the brain and the retina. The two proteins are generally expressed in different neurons with a few neurons containing both calcium binding proteins. Calbindin 28K is also present in the endocrine system. We have examined the cellular distribution of calbindin in the pancreatic endocrine cells of chick, rat and human and found variable distribution among the different endocrine cell types. We also describe the presence of calbindin in RINm5F cells, an insulin-producing tumor cell line derived from a radiation-induced rat insulinoma.

Animals↗
PubMed1989

Human papillomaviruses: are we ready to type?

The issue of determining which human papillomavirus (HPV) is present in a clinical specimen (typing specimens for HPVs) is receiving attention because HPVs cause condyloma acuminata and are associated with the continuum of disease which ranges from dysplasia to invasive genital cancer. Morphological inspection of precancerous lesions is not sufficient to determine which lesions will progress and which will not. A number of research tools based primarily on deoxyribonucleic acid hybridization have been developed. These permit identification and typing of HPV in genital tract scrapings or biopsies. Some HPV types (e.g., HPV-16 and HPV-18) have been identified in high-grade dysplasias and carcinomas more commonly than other types (e.g., HPV-6) and have been designated "high risk" types for cervical cancer. Thus, the question arises whether HPV typing would improve patient management by providing increased sensitivity for detection of patients at risk or by providing a prognostic indicator. In this review, the available typing methods are reviewed from the standpoint of their sensitivity, specificity, and ease of application to large-scale screening programs. Data implicating HPVs in the genesis of genital tract cancers are reviewed, as is the association of specific HPV types with specific outcomes. We conclude that there is currently no simple, inexpensive assay for HPV types, although such assays may be developed in the future. Analysis of the typing data indicates that, while HPV types can be designated high risk and low risk, these designations are not absolute and thus the low-risk group should not be ignored. In addition, interpretation of the data is complicated by finding high-risk types in individuals with no indication of disease. Insufficient data exist to indicate whether knowledge of the presence of a given HPV type is a better prognostic indicator than cytological or histological results. Thus, more research is needed before it can be determined whether typing information will augment the method currently in use for deciding treatment regimen and whether it warrants widespread use.

DNA Probes, HPV↗
PubMed1989

Impaired non-specific delayed cutaneous hypersensitivity in bird fancier's lung.

The relation between non-specific delayed cutaneous hypersensitivity and bird fancier's lung was investigated in 13 patients with the disorder. They were compared with 50 subjects who had no reason to have decreased non-specific delayed cutaneous hypersensitivity (control group) and 34 patients with pulmonary sarcoidosis. In addition, 13 patients with bird fancier's lung (11 of the original group) were tested at least one year after avoiding exposure to the causal antigen. Five antigens (candidine, staphylococcal toxoid, tuberculin purified protein derivative, trichophyton, and streptokinase-streptodornase) were injected intradermally (0.1 ml) and the mean weal diameter was measured at 48 hours. The mean weal size was significantly less in the subjects with bird fancier's lung at the time of diagnosis than in the control group (2.23 v 5.66 mm) but did not differ significantly from that of the subjects with sarcoidosis (2.80 mm) or from that of the bird fanciers with no exposure to the causal antigen for one year (2.75 mm). The impairment of non-specific delayed cutaneous hypersensitivity in patients with bird fancier's lung appears to be quantitatively similar to that occurring in sarcoidosis.

Adult↗
PubMed1989

Surgical treatment of bone metastases of the peripheral skeleton--a review of 33 cases.

Out of a total of 31 patients (26 females and five males) there were 24 complete and nine impending pathological fractures. These, treated from October 1985 to September 1987 at the Bordet Institute, were evaluated. Breast cancer was the most frequent underlying disease (66%) followed by lung cancer (12%). Eighteen lesions were treated by endoprosthetic replacement and 15 by an intramedullary fixation device. Bone cement was added to either of these. Satisfactory pain relief was obtained in 82% of the treated areas and restoration of function in 76%. Complications were rare but included one easily resolved superficial wound infection, four deep venous thromboses, movement limited to 21% (seven joints), and the changing of two fixation or reconstruction devices. Median survival time was 6 months; 35% of the patients were still alive after 12 months and 10% after 24 months.

Adult↗
PubMed1989

The FDA rhesus breeding colony at La Parguera, Puerto Rico.

Experiences of the Caribbean Primate Research Center (CPRC) with the Food and Drug Administration's (FDA) rhesus monkey breeding contract at La Parguera and lessons which should have been learned are discussed. Onset of the rainy season and timing of rhesus monkey conceptions for 1973-79 showed random association. Electrocardiographic recordings of a male rhesus monkey during reproductive activity indicated extremely high and highly variable heart rates following ejaculation.

Academies and Institutes↗
PubMed1988

Pineal-retinal molecular relationships; immunocytochemical evidence of calbindin-27 kDa in pineal transducers.

Calbindin-27 kDa immunocytochemical localization was studied concurrently in the pineal organ and retina from human as well as representatives of all vertebrate classes. Calbindin immunoreactivity was demonstrated in retinal cones (but not in rods) and in pineal transducers (cone-like and modified photoreceptor cells, pinealocytes) of a majority of amniotes. In contrast, no labelling was observed in anamniotes, except in retinal cones of the toad. Labelling was distributed through all cellular compartments (outer and inner segments, perikarya, pedicles or processes) of pineal transducers and retinal cones. Intra- and interspecific variations of calbindin contents are discussed.

Animals↗
PubMed1988

Characterization of human papillomavirus type 6b DNA isolated from an invasive squamous carcinoma of the vulva.

Human papillomavirus type 6 (HPV 6) DNA was detected in an episomal form in DNA extracted from an invasive squamous carcinoma of the vulva. The viral DNA, designated HPV6-T70, was molecularly cloned. Restriction analysis of the HPV6-T70 genome revealed an insertion of approximately 35 bp in the 5' portion of the upstream regulatory region relative to the prototype HPV 6b genome, cloned from a benign genital wart (E.-M. de Villiers, L. Gissmann, and H. zur Hausen, 1981, J. Virol. 40, 932-935). However, sequence analysis of the upstream regulatory region identified several alterations in the purine-thymidine-rich region spanning nucleotides 7292-7400. One insertion of 24 bp at position 7323 represented an exact tandem duplication of nucleotides 7300-7323. A second insertion of 58 bp at position 7350 had 84% positional identity to immediately adjacent HPV 6 sequences (nucleotides 7303-7356) and was also similar to the 74-bp insertion found at position 7348 in HPV-6vc, cloned from an invasive verrucous carcinoma of the vulva (R. F. Rando, D. E. Groff, J. G. Chirikjian, and W. D. Lancaster, 1986, J. Virol. 57, 353-356). A deletion of 49 bp (nucleotides 7351-7399) immediately followed the 58-bp insertion. The cloned HPV6-T70 DNA induced the morphological transformation of NIH 3T3 cells.

Animals↗
PubMed1988

Alterations in the regulatory region of the human papillomavirus type 6 genome are generated during propagation in Escherichia coli.

We analyzed the long control regions (LCRs) of seven human papillomavirus type 6b (HPV-6b) clones, which contained prototype HPV-6b sequences recloned into various plasmid vectors and propagated in different strains of Escherichia coli. Southern blot analysis and DNA sequencing demonstrated three different sequences, each distinct from the published prototype HPV-6b sequence. Two of the plasmids contained insertions of 24 and 94 base pairs (bp) and a 1-bp deletion. Four plasmids contained insertions of 24 and 58 bp and a deletion of 49 bp. One plasmid contained a single insertion of 77 bp. The 94-, and 58-bp insertions occurred at the same site and had 100% positional identity across their shared lengths. All changes were located in the purine-thymidine-rich region of the LCR (nucleotides 7292 to 7400). Two additional LCR sequences were detected by restriction analysis of two other HPV-6b clones. We conclude that the purine-thymidine-rich region of the LCR is a hot spot for recombination in E. coli and that the alterations are the result of recA-independent events. These results emphasize the need to rigorously prove that a cloned isolate is an authentic copy of the genomic DNA present in the original lesion. In addition, the data indicate that the HPV-6b LCR sequences employed in different laboratories may be different, even if their parental DNAs were identical. Finally, we discuss the need for caution in assigning biological significance to alterations in this region, in view of the limited data available on the true identity of the HPV-6b LCR.

Base Sequence↗
PubMed1987

Transcriptional regulation of the human papillomavirus-16 E6-E7 promoter by a keratinocyte-dependent enhancer, and by viral E2 trans-activator and repressor gene products: implications for cervical carcinogenesis.

The transcriptional promoter of the candidate E6-E7 transforming gene region of human papillomavirus (HPV)-16 (P97) was active in transiently transfected cervical carcinoma cells when linked to the HSV-1 tk or bacterial cat genes. Sequences 5' to P97 contain a short enhancer element responding to cellular factor(s) in uninfected human foreskin keratinocytes and in cervical carcinoma cells, but not in human or animal fibroblasts. The E2 trans-activator products of HPV-16 or of the related bovine papillomavirus (BPV)-1 further elevated HPV-16-driven transcripts in co-transfections, and required the presence of E2-binding ACC(N)6GGT cores in cis. A 'short E2' C-terminal repressor gene product (sE2) of HPV-16 or the BPV-1 sE2 repressor not only inhibited viral E2 trans-activation, but also suppressed enhancer response to keratinocytic factors. Suppression by the sE2 products was abolished by deletion of the E2-binding cores in cis or by a mutation in the sE2 DNA binding domain. The keratinocyte-dependent enhancer is likely to contribute to the epithelial cell tropism of HPV-16, and may direct persistent E6-E7 gene transcription in response to cellular factors in cervical carcinoma cells in which the viral E2 genes are inactive.

Animals↗