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Biomedical subjects

D Frank

Publications and source records attributed to D Frank.

At least 73 records · Page 4Linked to original sources
PubMed1994

Exoproduct secretions of Pseudomonas aeruginosa strains influence severity of alveolar epithelial injury.

To determine whether exoenzyme S plays a role in alveolar epithelial injury, two parental strains of Pseudomonas aeruginosa, PAK and PA103, were tested that produced large quantities of exoenzyme S. Strains PAK and PA103 differ in the form of exoenzyme S they produce. Strain PAK produces a 53-kDa protein that does not possess ADP-ribosyltransferase activity and large quantities of a 49-kDa protein that expresses ADP-ribosyltransferase activity. Strain PA103 produces the 53-kDa protein and low amounts of exoenzyme S activity. A quantitative experimental protocol was used to measure the protein permeability of the alveolar epithelium and the dissemination of the bacteria to the pleural space and circulation. The results indicate that instillation of PAK and PA103 resulted in significant lung injury. Control experiments utilizing isogenic, exoenzyme S-deficient, regulatory mutants in the infection model reduced the lung injury and the dissemination of instilled bacteria. Taken together these results suggest that alveolar epithelial injury correlated with the production of the 53-kDa form of exoenzyme S or other coordinately regulated factors.

ADP Ribose Transferases↗
PubMed1994

[The concept of myocardial infarct rehabilitation in phase III].

The benefit of outpatient rehabilitation in coronary artery disease is well documented in literature. Despite this, there is evident lack of rehabilitation facilities during phase III WHO in our country. Departments of Physical Medicine and Rehabilitation seem to be well suited to run ambulant rehabilitation programmes. Therefore we developed a comprehensive rehabilitation programme including physical training, dietary counselling and teaching lessons for patients. Physical training is strictly aerobic according to the guidelines of medical training therapy. Training time will rise systematically. To keep risks low, precise in- and exclusion criteria are defined. Regular training for the staff is mandatory. Uniformity of therapeutic interventions and documentation provide quick evaluation of therapeutic success.

Ambulatory Care↗
PubMed1993

Acute phase response to Salmonella in a pig liver perfusion model.

Livers from 7- to 14-day old pigs were maintained on a perfusion apparatus for 3 h. The perfused livers maintained physiologic and immunologic functions during perfusion. The perfused livers retained 78-94% of a non-recirculating inoculum of approximately 1-5 x 10(8) Salmonella choleraesuis (Scs), and cleared 94.9 +/- 1.7% of the retained (Scs) during the 3-h perfusion period. When the acute phase response (APR) was induced in liver donor pigs 24 h before liver perfusion, the perfused livers had diminished capability to retain, and greatly diminished capability to clear Scs. When sterile, filtered, and concentrated liver perfusate (LP) from previous, LPS-perfused livers was added to the perfusion fluid (PF) at 50 min of Scs perfusion (passive APR), Scs clearance was inhibited. When sterile, filtered LP from previously Scs perfused livers was added to the system, liver clearance was abolished, and Scs always grew in such livers during the 3 h perfusion period. The LP of livers perfused with Scs enhanced growth of Scs in an in vitro assay. These observations suggest that products of the acute phase response favor growth of Scs in vitro and in vivo.

Acute-Phase Reaction↗
PubMed1993

Effect of bovine immunodeficiency-like virus infection on immune function in experimentally infected cattle.

Bovine immunodeficiency-like virus (BIV) is a bovine lentivirus that has antigenic and genetic homology with the human immunodeficiency virus. Little work has been reported on the effect of BIV infection on bovine immune function. This study was designed to evaluate lymphocyte blastogenesis, mononuclear cell subset numbers, neutrophil function, hematology, and clinical signs in three groups of cattle. These groups were evaluated at 0-2 months post inoculation (PI, Group 1), 4-5 months PI (Group 2), or 19-27 months PI (Group 3). BIV infected animals were inoculated with the R-29 isolate of BIV in tissue culture cells, peripheral blood mononuclear cells from a R-29 infected calf, or a molecular clone of the R-29 isolate. Most inoculated animals seroconverted to BIV by Western immunoblot. BIV was reisolated from most of the animals inoculated. BIV infection was associated with an increase in the lymphocyte blastogenic response to the mitogen phytohemagglutinin in Groups 2 and 3. Neutrophil antibody dependent cell mediated cytotoxicity and neutrophil iodination were decreased (P < 0.05) in BIV infected cattle (Groups 2 and 3 and Group 3, respectively). All animals were clinically normal during the evaluation periods. Notable differences were not observed in the other assessments performed. Work with additional BIV isolates and over longer time frames is warranted.

Analysis of Variance↗
PubMed1993

Expression of an early myelopoietic antigen (CD33) on a subset of human umbilical cord blood-derived natural killer cells.

A new subset of natural killer (NK) cells was identified in human umbilical cord blood. This subset of CD56+/CD3- NK cells co-expressed the CD33 antigen, which is present on early hematopoietic progenitors confined to the myeloid lineage. The percentage of the CD56+/CD33+ cells among the CD56+/CD3- NK cells was 7.9 +/- 6.6% (n = 27) with a range of 1.4-25.5% and a considerable individual variability. Additionally, the majority of freshly isolated CD56+/CD33+ cells co-expressed the CD2 and CD7 antigen, a minor proportion co-expressed the CD8 antigen but essentially all of the cells stained negative for CD16 and CD57. Morphological analysis of the CD56+/CD33+ cells showed the features of large agranular lymphocytes. From some of the samples, the CD56+/CD33+ NK cells were cultivated and expanded in vitro by incubation of the cells with interleukin 2 (IL-2) for up to 50 days. Morphological analysis of the cultured CD56+/CD33+ cells showed the features of large granular lymphocytes (LGL). The IL-2-expanded CD56+/CD33+ NK cells showed only a low cytolytic activity against K562 target cells, whereas most of the NK activity of the expanded cells was contributed by the CD56+/CD33- NK cells.

Antigens, CD↗
PubMed1993

Alveolar epithelial injury and pleural empyema in acute P. aeruginosa pneumonia in anesthetized rabbits.

We developed an experimental model of acute Pseudomonas aeruginosa pneumonia in anesthetized ventilated rabbits to determine whether bacterial-induced injury to the alveolar epithelium would occur and the effect of the injury on the pleural space. Dose-response studies established that 10(9) colony-forming units of P. aeruginosa (wild-type strain, PAO-1) were required to injure the epithelial barrier and to cause pleural empyema with exudative pleural effusions that contained both the instilled alveolar protein tracer and P. aeruginosa. We explored the mechanisms of P. aeruginosa-induced lung and pleural injury by using three isogenic bacterial strains to compare several extracellular virulence products. PAO-S21, which carries an insertion mutation in a regulatory gene that prevents the production of exoenzyme S, resulted in no lung or pleural injury. PAO-R1, which carries a deletion in a regulatory gene that controls the production of elastase and alkaline protease, caused the same degree of lung and pleural injury as PAO-1 did. Instillation of PLC-SRN, which has both structural genes encoding phospholipase C activity deleted, resulted in a moderate reduction in alveolar epithelial injury. Although other products may be involved, exoenzyme S and phospholipase C are important in mediating injury to the alveolar epithelial barrier in acute P. aeruginosa pneumonia in rabbits.

Anesthesia↗
PubMed1993

[Religious dogmatism and ecclesiogenic neuroses. A quasi-experimental contribution to Catholic church communities between tradition and pleuralism].

Schaetzing (1955) characterizes "ecclesiogen neurosis" as mental disturbances, which are caused by "dogmatism of the church". To prove his thesis that the factor "dogmatism of the church" goes along with ecclesiogen-neurotic symptoms we use as factorial levels two different forms of Catholic congregations, that is to say a "traditional congregation" (high "dogmatism of the church") and a "pluralistic" one (low "dogmatism of the church"). In this quasi-experimental design 93 Catholics who are involved in the church of a "traditional" congregation and 70 of a "pluralistic" one are examined. The correctness of categorizing these congregations to the factorial levels is proved empirically. To record ecclesiogen-neurotic symptoms we consider "religious anxiety" (Kim, 1988) and "depressivity" (Zerssen, 1976). Our findings show that active Catholics of both congregations show a distinct higher expressivity in the dependent variable "depressivity" compared with the mean population. The comparison of both congregation samples by analysis of covariance shows furthermore, that the dependent variable "religious anxiety" is significantly higher in the "traditional" congregation than in the "pluralistic" one. The results are later critically discussed.

Adult↗
PubMed1992

Application of an organic solvent extraction to the determination of catechol-O-methyltransferase activity by high-performance liquid chromatography in human mononuclear cells.

We report here a method for measuring mononuclear cell catechol-O-methyltransferase (COMT) activity which is ideally adapted to clinical studies. The method measures the O-methylation of dopamine to 3-methoxytyramine and 4-methoxy-3-hydroxyphenethylamine. Whole mononuclear cell sonicate is incubated with saturating concentrations of dopamine, S-adenosyl-L-methionine and magnesium chloride in sodium-potassium phosphate buffer at pH 7.3. An organic solvent extraction using ethyl acetate is then used for product separation, followed by high-performance liquid chromatography with electrochemical detection for product separation and quantification. This method allows both O-methylated products, 3-methoxytyramine and 4-methoxy-3-hydroxyphenethylamine, to be isolated and quantified separately. The apparent Michaelis constants for dopamine and S-adenosyl-L-methionine using this method are similar to values reported previously (0.51 and 14 microM, respectively). The optimal concentration of magnesium chloride is eight to ten times higher than previously reported. No endogenous inhibitors were apparent using this assay. The within-day coefficient of variation using this method is 7% when measuring 3-methoxytyramine and 5% when measuring 4-methoxy-3-hydroxyphenethylamine. The between-day coefficient of variation is 11%. Mononuclear cell COMT activity can be detected using protein concentrations as low as 0.75 mg/ml, corresponding to 2-3 ml of whole blood. The small amount of blood required per sample allows multiple sample analysis from a single patient, including infants.

Adult↗
PubMed1992

Comparative biological responses of rabbits infected with human T-lymphotropic virus type I isolates from patients with lymphoproliferative and neurodegenerative disease.

An experimental rabbit model was used to determine host responses to infection by various human T-lymphotropic virus type-I (HTLV-I) strains. Seven groups of 4 to 5 rabbits each were inoculated with lethally-irradiated HTLV-I-infected cell lines derived from patients with adult T-cell leukemia/lymphoma or from patients with HTLV-I-associated myelopathy. Four separate control groups of 2 rabbits each were inoculated with similarly prepared HTLV-I-negative cells derived from rabbits or humans. Anti-viral antibody responses were assessed by immunoblot assay and hematologic parameters were measured using automated cell counters and cytologic staining. The virologic status of challenged rabbits was determined by co-culture and HTLV-I antigen capture assay, as well as by polymerase chain reaction (PCR) amplification of HTLV-I DNA from peripheral blood mononuclear cells (PBMC) or tissues. The HTLV-I inocula could be separated into groups based upon their infectivity to rabbits: highly infectious strains elicited intense serologic responses and were detected frequently in tissues by antigen and PCR assays, while other strains were moderately to poorly infectious, induced weak antibody responses and were infrequently detected by antigen and PCR assays. Overall, PBMC appeared to have the greatest quantity of HTLV-I containing cells, while bone marrow was a poor source of virus. No clinical or hematologic abnormalities were evident during the 24-week course of infection. Taken together, our results suggest there is heterogeneity in the biological response to HTLV-I infection which is, in part, dependent on the infecting strain of virus.

Animals↗
PubMed1992

Coronary atherectomy: overview and implications for nursing.

Coronary atherectomy, a new invasive procedure for the treatment of atherosclerotic heart disease, consists of the excision and removal of atherosclerotic tissue from coronary artery walls. This article provides current information on atherectomy, including its potential advantages over percutaneous transluminal coronary angioplasty (PTCA). Indications, limitations, medical research, and implications for nursing research are described. A case study is presented.

Atherectomy, Coronary↗
PubMed1992

An essential splicing factor, SLU7, mediates 3' splice site choice in yeast.

Recently, we have reported the identification of several genes that exhibit genetic interactions with the U5 snRNA. Two of these genes, SLU4 and SLU7 (SLU: synergistic lethal with U5 snRNA), encode products required for the second catalytic step of splicing. To analyze the specific roles of SLU4 and SLU7, we have determined how mutants influence the relative usage of competing 3' splice sites. We find that mutations in SLU7 eliminate the normal 20-fold preference for 3' splice sites located > 22 nucleotides downstream of the branchpoint. In contrast, mutations in SLU4 inhibit usage of all 3' splice sites, regardless of their location. This suggests that SLU7 is involved in the process of 3' splice site choice, whereas SLU4 fulfills a generic requirement for the second step. We show that SLU7 is an essential gene that contains a small motif with striking similarity to the cysteine-rich zinc knuckle of retroviral nucleocapsid proteins, which has been implicated in RNA binding. Mutational analysis of SLU7 indicates that this motif influences the efficiency, but not the sequence specificity, of 3' splice site selection. The identification of a component of the constitutive splicing machinery that can promote 3' splice site choice has potentially important implications for alternative splicing.

Amino Acid Sequence↗
PubMed1992

Synthetic lethal mutations suggest interactions between U5 small nuclear RNA and four proteins required for the second step of splicing.

To investigate the function of the U5 small nuclear ribonucleoprotein (snRNP) in pre-mRNA splicing, we have screened for factors that genetically interact with Saccharomyces cerevisiae U5 snRNA. We isolated trans-acting mutations that exacerbate the phenotypes of conditional alleles of the U5 snRNA and named these genes SLU, for synergistically lethal with U5 snRNA. SLU1 and SLU2 are essential for the first catalytic step of splicing, while SLU7 and SLU4 (an allele of PRP17 [U. Vijayraghavan, M. Company, and J. Abelson, Genes Dev. 3:1206-1216, 1989]) are required only for the second step of splicing. Furthermore, slu4-1 and slu7-1 are lethal in combination with mutations in PRP16 and PRP18, which also function in the second step, but not with mutations in factors required for the first catalytic step, such as PRP8 and PRP4. We infer from these data that SLU4, SLU7, PRP18, PRP16, and the U5 snRNA interact functionally and that a major role of the U5 snRNP is to coordinate a set of factors that are required for the completion of the second catalytic step of splicing.

Base Sequence↗
PubMed1992

Localized expression of a Xenopus POU gene depends on cell-autonomous transcriptional activation and induction-dependent inactivation.

We have cloned a cDNA encoding a Xenopus POU domain protein, XLPOU91, which is expressed at high levels in gastrula embryos. XLPOU91 transcription initiates at the midblastula transition, and declines to low levels by late neurula stages. In early neurula embryos, XLPOU91 transcripts are enriched 35-fold in the most ventroposterior versus anterior regions. Initial transcriptional activation of the gene is cell autonomous; the gene is activated in dissociated gastrula stage embryos as well as in animal cap explants. Cell-cell communication is needed for proper temporal down-regulation of XLPOU91 expression in late neurula embryos; cell dissociation during blastula stages or removal of explants from the embryo prevents normal transcriptional shunt down. Explants treated with peptide growth factors (PGFs) mimic the normal temporal and spatial shut down in whole embryos. This negative regulatory pathway may be important for determining cell fate or maintaining an inducible state in the ventroposterior region of the embryo.

Amino Acid Sequence↗
PubMed1991

Demethylation of CpG islands in embryonic cells.

DNA in differentiated somatic cells has a fixed pattern of methylation, which is faithfully copied after replication. By contrast, the methylation patterns of many tissue-specific and some housekeeping genes are altered during normal development. This modification of DNA methylation in the embryo has also been observed in transgenic mice and in transfection experiments. Here we report the fate in mice of an in vitro-methylated adenine phosphoribosyltransferase transgene. The entire 5' CpG island region became demethylated, whereas the 3' end of the gene remained modified and was even methylated de novo at additional sites. Transfection experiments in vitro show that the demethylation is rapid, is specific for embryonic cell-types and affects a variety of different CpG island sequences. This suggests that gene sequences can be recognized in the early embryo and imprinted with the correct methylation pattern through a combination of demethylation and de novo methylation.

Adenine Phosphoribosyltransferase↗
PubMed1991

Strain differences in mouse brain weight gain and spatial-location scores during postnatal development.

Brain weight and performance on a spatial-location test were measured from birth to weaning on mouse strains CD1, Balb/c, and their F1 cross. For CD1, onsets of both the last rapid-brain-growth stage and nonzero scores on the spatial-location test were around age 17 days; asymptotes of both were reached about age 23 days. Balb/c and F1 had at least 5- to 6-day delays of both onsets and asymptotes. For the strains studied, onset of nonzero performance on the spatial-location test may be a provisional indicator of onset of significant and rapid brain growth after age 15 days. The delayed F1 brain growth stage could indicate that control of brain growth about age 20 days resides in an inhibitory factor present in Balb/c but not in CD1.

Animals↗
PubMed1991

Transient expression of XMyoD in non-somitic mesoderm of Xenopus gastrulae.

XMyoD is the earliest marker of muscle development in Xenopus embryos and is expressed in presumptive somites in the late gastrula. In the early gastrula, in situ hybridization showed XMyoD transcripts in precursors of both muscle and non-muscle mesoderm. Embryos ventralized by UV irradiation made no muscle, but expressed XMyoD transiently. Embryo explants that differentiated ventral mesoderm also expressed XMyoD transiently. These results show that the initiation of XMyoD expression is not sufficient to convert cells to muscle and suggest that XMyoD is expressed in response to a general mesodermalizing signal; expression is stabilized and enhanced only in muscle precursors that have received a dorsalizing signal.

Animals↗
PubMed1990

Demethylation of genes in animal cells.

Tissue-specific animal cell genes are usually fully methylated in the germ line and become demethylated in those cell types in which they are expressed. To investigate this process, we inserted a methylated IgG kappa gene into fibroblasts and lymphocytes at various stages of development. The results show that this gene undergoes demethylation only in the mature lymphocytes and therefore suggest that the ability to demethylate a gene is developmentally regulated. These studies were supported by similar experiments using the rat Insulin I gene, and in this case it appears that the cis-acting elements that control demethylation may be different from those responsible for gene activation. The ability to demethylate the housekeeping gene APRT is also under developmental control, because this occurs only in embryonic cells, both in tissue culture and in transgenic mice.

Adenine Phosphoribosyltransferase↗