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PubMed2004

Evaluation of P-glycoprotein, HER-2/ErbB-2, p53, and Bcl-2 in primary tumor and metachronous lung metastases in patients with high-grade osteosarcoma.

BACKGROUND: Investigation of the relation between primary tumor and metastatic disease is necessary for the identification of predictive factors for postrecurrence survival (PRS) in patients with recurrent osteosarcoma. METHODS: Cellular levels of P-glycoprotein, ErbB-2, p53, and Bcl-2 expression were evaluated in primary tumor biopsy and metachronous pulmonary metastasis specimens from 19 patients with high-grade osteosarcoma. Results were analyzed for differences between primary tumor and pulmonary metastases and for correlations between expression patterns and survival. RESULTS: Positive staining in lung metastases was noted in 68%, 53%, 32%, and 84% of patients for P-glycoprotein, ErbB-2, p53, and Bcl-2, respectively. These percentages were higher than those observed in primary tumor specimens for all genetic markers evaluated, with a significant difference in the percentage of patients with positive staining for P-glycoprotein (68% vs. 32%; P = 0.05) and a near-significant difference in the percentage of patients with positive staining for Bcl-2 (84% vs. 53%; P = 0.08). Patients with ErbB-2 expression in the primary tumor were more likely to have multiple metastases and shorter recurrence-free intervals compared with patients in whom ErbB-2 expression was not observed, whereas differences in P-glycoprotein, p53, and Bcl-2 expression were not related to differences in metastatic pattern. PRS was influenced by p53 expression levels in pulmonary metastases, with patients who had negative staining for p53 having a significantly better PRS rate relative to patients with positive staining for p53 (3-year PRS rate: p53-negative, 64%; p53-positive, 17%; P = 0.008). CONCLUSIONS: In the current study of patients with high-grade osteosarcoma, most patients exhibited increased cellular expression of P-glycoprotein, ErbB-2, and Bcl-2 in recurrent pulmonary metastases compared with primary tumor. Further studies aimed at investigating the relation between altered p53 expression in lung metastases and postrecurrence survival are recommended.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2002

Prenatal diagnosis of Pierre-Robin sequence as part of Stickler syndrome.

Stickler syndrome or hereditary progressive arthro-ophthalmopathy, is an autosomal dominant condition characterized by ocular manifestations, arthritic changes, orofacial features and deafness, in variable degrees.We report the first case of prenatal diagnosis of Stickler syndrome in a child with a Pierre-Robin sequence (PRS) causing a polyhydramnios. When isolated polyhydramnios is not explained by immunological, metabolic or infectious causes, swallowing difficulty due to PRS must be considered. As PRS is aetiologically heterogeneous, the prognosis depends on the cause. Genetic investigations and familial history must be taken into account. Here, in a context of familial Stickler syndrome, making the prenatal diagnosis of PRS as part of Stickler syndrome allowed us to reassure the parents and to anticipate airway trouble at the child's birth.

Abnormalities, Multiple↗
PubMed1992

Synthetic "interface" peptides alter dimeric assembly of the HIV 1 and 2 proteases.

Retroviral proteases are obligate homodimers and play an essential role in the viral life cycle. Dissociation of dimers or prevention of their assembly may inactivate these enzymes and prevent viral maturation. A salient structural feature of these enzymes is an extended interface composed of interdigitating N- and C-terminal residues of both monomers, which form a four-stranded beta-sheet. Peptides mimicking one beta-strand (residues 95-99), or two beta-strands (residues 1-5 plus 95-99 or 95-99 plus 95-99) from the human immunodeficiency virus 1 (HIV1) interface were shown to inhibit the HIV1 and 2 proteases (PRs) with IC50's in the low micromolar range. These interface peptides show cognate enzyme preference and do not inhibit pepsin, renin, or the Rous sarcoma virus PR, indicating a degree of specificity for the HIV PRs. A tethered HIV1 PR dimer was not inhibited to the same extent as the wild-type enzymes by any of the interface peptides, suggesting that these peptides can only interact effectively with the interface of the two-subunit HIV PR. Measurements of relative dissociation constants by limit dilution of the enzyme show that the one-strand peptide causes a shift in the observed Kd for the HIV1 PR. Both one- and two-strand peptides alter the monomer/dimer equilibrium of both HIV1 and HIV2 PRs. This was shown by the reduced cross-linking of the HIV2 PR by disuccinimidyl suberate in the presence of the interface peptides. Refolding of the HIV1 and HIV2 PRs with the interface peptides shows that only the two-strand peptides prevent the assembly of active PR dimers. Although both one- and two-strand peptides seem to affect dimer dissociation, only the two-strand peptides appear to block assembly. The latter may prove to be more effective backbones for the design of inhibitors directed toward retroviral PR dimerization in vivo.

Amino Acid Sequence↗
PubMed1987

The effect of progesterone on the localization of progesterone receptors in the nuclei of chick oviduct cells.

The location of occupied and unoccupied progesterone receptors (PR) in chick oviduct cells was studied by immuno-electron microscopy with the use of a highly specific polyclonal anti-PR antibody and pre-embedding modifications of the peroxidase-anti-peroxidase- (PAP-) or immunogold-silver methods. Both methods revealed a nuclear localization of the PRs. The location of the PR in the nucleus was studied in detail by means of the immunogold-silver method. The most intense labelling for unoccupied PRs was in the condensed chromatin. After occupation of PRs with progesterone (P), decondensation or dispersion of chromatin was observed. At the same time, the labelling in the border area of condensed and dispersed chromatin, and in the dispersed chromatin, increased. The changes were statistically significant. The results can be explained by conformational changes of the PR-containing chromatin rather than by translocation of PRs from one site to another.

Animals↗
PubMed1986

Morphology and fibrinolytic activity of canine autogenous mesothelium used as venous substitute.

Autogenous mesothelium was used as venous substitute in ten dogs. Patches of mesothelium of three different origins were grafted into the anterior wall of the common iliac veins (CIV): peritoneum taken from and including the posterior rectus sheath (PRS), simple peritoneum (P) and mesentery (M). Animals were killed after 2, 4, 8, and 16 days and after 3 months. The segments of CIV, including the patches, were removed for study. On light microscopy, the PRS grafts showed a normal mesothelium but marked submesothelial fibrosis. The M and P grafts showed normal mesothelium and only mild fibrous thickening. On scanning electron microscopy, there was a perfect continuity of the mesothelial cells and the normal endothelium at the suture line. In the center of the graft, the cells had become elongated along the axis of blood flow. Fibrinolytic activity (FA) was measured by a standardized fibrin plate technique and quantitated in tissue activator units per gram of tissue (TAU/g). The mean FA of iliac vein specimens was 1101.7 +/- 133.3 TAU/g (mean +/- SEM). The mean FA determined before grafting for each kind of mesothelium was the following: PRS = 418.8 +/- 26.9 TAU/g; P = 873.0 +/- 107.1 TAU/g; M = 1142.3 +/- 91.4 TAU/g where only PRS showed values significantly lower than iliac vein mean FA (P less than 0.001). Postoperatively, the mesothelial FA, after an initial reduction, increased on day 4 and reached values significantly higher than the control values (1445.7 +/- 204.1 TAU/g tissue vs 853.1 +/- 62.3 TAU/g tissue; P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Pharmaceutical representatives in academic medical centers: interaction with faculty and housestaff.

OBJECTIVE: To determine the nature, frequency and effects of internal medicine housestaff and faculty contacts with pharmaceutical representatives (PRs). DESIGN AND SETTING: The authors surveyed internal medicine faculty at seven midwest teaching hospitals and housestaff from two of the teaching programs. The survey asked about type and frequency of contacts with PRs and behavior that might be related to these contacts. T-tests and logistic regression were used to estimate the relationship between reported physician contacts and behavioral changes. PARTICIPANTS: Two hundred forty faculty (78%) and 131 house officers (75%) responded to the survey. RESULTS: Faculty and housestaff averaged 1.5 brief contacts per month with PRs. Housestaff averaged more than one meal/month at pharmaceutical company expense. Twenty-five percent of faculty and 32% of residents reported changing their practices at least once based on PR contact. Independent predictors of faculty change in practice were brief or extended conversations and free meals. Predictors of faculty requests for formulary addition were brief conversations and receipt of honoraria or research support. Only brief conversations independently predicted housestaff changes in practice. CONCLUSION: Academic housestaff and faculty have frequent PR contact; such contact is related to changes in behavior. The potential for influence of PRs in academic medical centers should be recognized, and their activities should be evaluated accordingly.

Academic Medical Centers↗
PubMed1997

Specificity of Retroviral Proteinases Based on Substrates Containing Tyrosine and Proline at the Site of Cleavage.

The retroviral proteinase (PR) plays crucial roles in the viral life cycle, therefore it is a target for chemotherapy. However, resistance rapidly develops due to frequent mutations. Studies to determine the common features of the specificity of different retroviral PRs may help to design broad spectrum inhibitors and reduce the possibility of viable mutants. We have studied the specificity of various retroviral proteinases including those the PR of HIV-1, HIV-2, equine infectious anemia virus and avian myeloblastosis virus using oligopeptide substrates. A series of oligopeptides containing substitutions in a sequence Val-Ser-Gln-Asn-Tyr*Pro-Ile-Val-Gln (asterisk indicates the site of cleavage) representing a naturally occurring cleavage site in HIV-1 was used to characterize the seven substrate binding subsites of the enzymes. The unsubstituted substrate is a typical class 1 cleavage site substrate containing an aromatic amino acid and a proline residue at the site of cleavage. The largest differences in kinetics of substrate hydrolysis were obtained with peptides containing substitutions of the Ser and Asn residues. Detailed analysis of the results by molecular modeling and comparison with previously reported data revealed the common characteristics of the specificity of the PRs as well as its strong dependence on the sequence context of the substrate. However, molecular modeling in many cases provided explanation for the sequence context dependence. Also, comparison of the specificity of the enzymes suggests that the specificity of HIV-1 and -2 PRs is rather exceptional preferring hydrophilic residues at the most discriminative positions while other PRs prefer hydrophobic residues.

Journal Article↗
PubMed2001

Characterization of the prfA virulence gene cluster insertion site in non-hemolytic Listeria spp.: probing the evolution of the Listeria virulence gene island.

The prfA virulence gene cluster is present between prs and ldh in the pathogenic L. monocytogenes and L. ivanovii, but absent from the non-pathogenic L. innocua and L. welshimeri. To probe the evolution of this virulence gene cluster, we sequenced the prs-ldh intergenic region in L. welshimeri and L. innocua. Two ORFs (ORFA and ORFB) were found in both species as well as in L. monocytogenes. Another ORF of unknown function (ORFZ) was found in L. monocytogenes and L. innocua, while two unique ORFs were present in L. welshimeri. ORFA and ORFB showed significant functional constraint, suggesting that further investigations in the functions of these genes, including possible roles in horizontal gene transfer or sequence deletion, are warranted. DNA sequences homologous to Tn1545 integration consensus sequences were found downstream of prs and ORFB, thus defining the likely junctions of the virulence gene island and indicating that the prs-ldh intergenic region may represent a Tn insertion hot spot. Our results are consistent with the hypothesis that a combination of horizontal gene transfer and deletion events mayhave been involved in the evolution of the prfA virulence gene cluster in Listeria.

Animals↗
PubMed2003

Pierre-Robin syndrome associated with Chiari type I malformation.

CASE REPORT: Pierre-Robin syndrome (PRS) is a rare congenital malformation that shows severe micrognathia and cleft soft palate. A 15-year-old boy who was admitted with occipital headache and gait disturbance was diagnosed with PRS. Radiological evaluation revealed severe herniation of the cerebellar tonsil and multiple craniovertebral osseous anomalies. We carried out foramen magnum decompression (FMD) with duroplasty. Postoperative MRI showed the cerebellar tonsil was freed from strangulation. RESULT AND CONCLUSION: This patient presented with the common finding between PRS and Chiari type I on the embryological aspect by illustrating pathophysiology of the Chiari I malformation. To our knowledge, this is the first reported case of PRS associated with Chiari malformation type I.

Adolescent↗
PubMed2002

Brainstem dysfunction: a possible neuroembryological pathogenesis of isolated Pierre Robin sequence.

UNLABELLED: Pierre Robin sequence (posterior U-shape cleft palate, glossoptosis, retrognathia) (PRS) is a frequent and heterogeneous neonatal condition of obscure origin. We show here that orodigestive and cardiorespiratory functional disorders are very frequent in PRS and that these functional disorders, as well as anatomical and embryological data, argue for the involvement of brainstem dysfunction in the pathogenesis of some cases of isolated PRS. A total of 66 infants consecutively admitted for isolated PRS were followed-up with observations and investigations focused on their orodigestive and cardiorespiratory disorders. Neonatal clinical examination and neonatal anatomical aspects of the three orofacial features of the sequence were evaluated. Feeding difficulties and respiratory disorders were recorded and infants were classified according to three grades of severity. The relation between functional severity grade and neonatal orofacial features was evaluated, as well as the relation between functional severity grade and specific criteria characterising oesophageal and laryngeal motility and cardiac orthoparasympathetic imbalance. In the first weeks of life, sucking and swallowing disorders (100%), excessive regurgitation (94%), upper airways obstruction (50%), and cardiac vagal overactivity (59%) were noted. Correlation of anatomical features with functional severity grades was poor except for extreme forms of glossoptosis and retrognathia. Specific anomalies of oesophageal motility, pharyngolaryngeal tone and parasympathetic cardiac regulation were described. These anomalies were more frequent in children with the two higher grades of functional severity. CONCLUSION: infants with Pierre Robin sequence have early and severe anomalies of orodigestive and cardiorespiratory function which do not appear to be related solely to anatomical features and which require proper medical management. We suggest a prenatal and neonatal brainstem dysfunction as a neuroembryological hypothesis to explain the onset of some cases of Pierre Robin sequence.

Brain Diseases↗
PubMed2004

Spatial avoidance of littoral and pelagic invertebrate predators by Daphnia.

Studies on spatial avoidance behaviour of predators by prey often ignored the fact that prey typically face multiple predators which themselves interact and show a spatial pattern in abundance and predation rates (PRs). In a series of laboratory experiments, we investigated predation risk (PRI) and horizontal migration of the cladoceran Daphnia magna between open water and vegetation in response to two important invertebrate predators with a contrasting spatial distribution: pelagic Choaborus and vegetation-associated Ischnura. As expected, PRI by Chaoborus was higher in open water due to higher numbers and higher PRs of Chaoborus, while for Ischnura, PRI was highest in the vegetation due to higher densities, despite lower PRs of Ischnura. In accordance with this, Daphnia moved into the vegetation in the presence of the pelagic Chaoborus alone. In the presence of Ischnura alone, however, Daphnia showed no response. We hypothesize this may be the result of a constitutive behaviour of Daphnia to avoid pelagic fish, which impedes a response to the open water. In the combined predator treatment, Daphnia migrated to the open water zone. The increased risk of predation in the vegetation, due to a facilitating effect of Chaoborus on Ischnura PRs is believed to have caused this migration of the Daphnia. This response of Daphnia declined through time and Daphnia moved toward the vegetation. A decline in the activity of the Ischnura larvae through time may have switched the risk balance in favour of the vegetation environment.

Animals↗
PubMed2003

Cerebral autoregulation during orthostatic stress in healthy controls and in patients with posturally related syncope.

Posturally related syncope (PRS) is a common and distressing problem, which frequently occurs in people with no apparent clinical disorder and is ultimately caused by a reduction in blood supply to the brain. The aim of this study was to compare cerebrovascular responses to orthostatic stress in otherwise healthy patients suffering from PRS, and who were shown to have a poor orthostatic tolerance (n=28), with those in healthy control subjects with good orthostatic tolerance (n=11). Responses of heart rate, arterial blood pressure, end tidal carbon dioxide and middle cerebral artery (MCA) blood flow velocity were determined during a progressive orthostatic stress test of combined head-up tilting and lower body suction, which was continued until presyncope. We assessed the efficiency of autoregulation of cerebral blood flow from the relationship between values of MCA velocity and pressure obtained over the expected range for autoregulation (> 55 mmHg). All patients with PRS had a significant correlation between MCA velocity and pressure, but this was seen in only two of the controls. Furthermore, the values of the correlation coefficients were significantly higher in patients than controls, (p<0.001). We interpret these data as indicating that autoregulation in patients with PRS is less effective than in controls and suggest that this provides evidence for a link between abnormalities of regulation of the cerebral circulation and predisposition to syncope.

Adult↗
PubMed1984

Plasma renin substrate, renin activity, and aldosterone levels in a sample of oral contraceptive users from a community survey.

Fasting plasma renin substrate (PRS), plasma renin activity (PRA), plasma aldosterone (PA), and blood pressure (BP) levels were measured from 212 apparently healthy normotensive nonpregnant white women aged 21 to 39 years, selected on the basis of oral contraceptive (OC) use of nonuse in 1976 following a community survey in East Boston. The mean PRS level was 7118 ng/dl among OC users and 1935 ng/dl among nonusers (p less than 0.0001). In contrast, mean PRA was 2.9 ng of angiotensin 1 per milliliter per hour among users and 3.0 ng of angiotensin l/ml/hr among nonusers (p = NS); mean PA levels were 26.2 ng/dl and 25.4 ng/dl, respectively (p = NS). Mean systolic BPs were 113.8 mm Hg among current OC users and 111.2 mm Hg among nonusers (p = 0.078); diastolic BPs were 68.5 and 68.9, respectively (p = NS). These data indicate a greater than three-fold increase in PRS among current OC users compared to nonusers, with virtually identical PRA and PA levels. The data indicate that normotensive women using OCs maintain normal PRA and PA levels despite marked elevations in PRS.

Adult↗
PubMed1983

Posterior rhythmic slow activity in EEG after eye closure.

During a 20 month period, EEGs in 7 patients, ages 6-16 years, showed a distinctive posterior rhythmic slow (PRS) activity brought on by eye closure. Following eye opening for 5-10 sec, eye closure on command was followed by a rhythmic high amplitude (100-250 microV) slow wave discharge of 3-4 c/sec lasting for 1.5-3 sec after a latency of 300-500 msec. Its distribution was limited to the occipital, posterior temporal and parietal regions. It was always bilaterally synchronous, occurred symmetrically or asymmetrically and fatigued easily. Of the 7 initial EEGs, only 2 had other EEG abnormalities. One patient, in a subsequent EEG, developed spontaneous PRS unrelated to eye closure. Clinical histories on the 7 patients showed 5 with various types of seizure disorders, 1 with attention deficit disorder, and 1 with Tourette syndrome. Neurological examination was normal in all patients, while computerized tomography or radioisotope brain scan was normal in 4. We suggest that PRS after eye closure represents a variant of the non-specific spontaneously occurring PRS described by Aird and Gastaut and others. It was found only in children and was not found to be helpful in diagnosing a seizure disorder or structural abnormality. Furthermore, such a discharge should not be interpreted as epileptiform activity.

Adolescent↗
PubMed1983

Resistance to tobacco necrosis virus induced by salicylate in detached tobacco leaves.

Sodium salicylate reduced both the size and viral antigen content of non-self-limiting necrotic lesions produced by tobacco necrosis virus (TNV) in detached tobacco leaves during the partly localized reaction to virus. The antiviral effect of salicylate occurred at concentrations close to the limits of toxicity, and depended on the timing of administration. Both viral antigen accumulation and lesion size were strongly inhibited by a continuous supply of salicylate before or just after virus infection. Salicylate treatment did not prevent TNV accumulation when given after the establishment of infection or when arrested 24 h after TNV inoculation. Both procedures, however, did limit lesion enlargement. These results constitute a limit for the use of salicylate as a chemotherapeutic agent but do not exclude its use in limiting the pathogenetic effects of the virus. The salicylate treatments induced the formation of four pathogenesis-related proteins (PRs). The PRs formation was stimulated during the first 8 h of treatment and persisted for some time after the salicylate supply was discontinued. No correlation was found between the presence of PRs and the reduction of TNV accumulation: low salicylate concentrations (0.25 mM) inducing the formation of the PRs did not induce resistance against the multiplication and/or cell-to-cell spread of TNV.

Plant Viruses↗
PubMed1980

Delayed-alternation performance after selective lesions within the prefrontal cortex of the cat.

On the basis of new neuroanatomical findings on relationships between subregions of the mediodorsal thalamic nucleus and the prefrontal cortex of the cat, it was attempted to investigate the relative importance of prefrontal subfields with the aim of obtaining evidence in favor of a functional inequality of different prefrontal subfields. Four areas, named presylvian (PRS), proreal (PR), dorsomedial (DM), and orbito-insular (OI) sectors, were ablated successfully in 30 adult animals. Performance of a 10-sec delayed-alternation task was compared pre- and postoperatively. Furthermore, most of the cats had to learn an extension of this task postoperatively, using a 20-sec delay period, and lastly, these animals were subjected to an extinction test. Significant performance differences were obtained between cats of different groups in all three tasks. Lesions of subregion PR, and even more of subregion PRS, led to severe behavioral deterioration, whereas lesions of subregion OI were without effect, when compared with the behavior of a sham-operated control group. PRS-cats, furthermore, showed motor disturbances during the first postoperative week. The results obtained suggest that it is possible to subdivide the cat's prefrontal cortex functionally. In addition, it is hypothesized that behavioral changes in cats of groups PRS and PR are due to an inability to use kinesthetic information properly.

Animals↗
PubMed1993

Plant 'pathogenesis-related' proteins and their role in defense against pathogens.

The hypersensitive reaction to a pathogen is one of the most efficient defense mechanisms in nature and leads to the induction of numerous plant genes encoding defense proteins. These proteins include: 1) structural proteins that are incorporated into the extracellular matrix and participate in the confinement of the pathogen; 2) enzymes of secondary metabolism, for instance those of the biosynthesis of plant antibiotics; 3) pathogenesis-related (PR) proteins which represent major quantitative changes in soluble protein during the defense response. The PRs have typical physicochemical properties that enable them to resist to acidic pH and proteolytic cleavage and thus survive in the harsh environments where they occur: vacuolar compartment or cell wall or intercellular spaces. Since the discovery of the first PRs in tobacco many other similar proteins have been isolated from tobacco but also from other plant species, including dicots and monocots, the widest range being characterized from hypersensitively reacting tobacco. Based first on serological properties and later on sequence data, the tobacco PRs have been classified in five major groups. Group PR-1 contains the first discovered PRs of 15-17 kDa molecular mass, whose biological activity is still unknown, but some members have been shown recently to have antifungal activity. Group PR-2 contains three structurally distinct classes of 1,3-beta-glucanases, with acidic and basic counterparts, with dramatically different specific activity towards linear 1,3-beta-glucans and with different substrate specificity. Group PR-3 consists of various chitinases-lysozymes that belong to three distinct classes, are vacuolar or extracellular, and exhibit differential chitinase and lysozyme activities. Some of them, either alone or in combination with 1,3-beta-glucanases, have been shown to be antifungal in vitro and in vivo (transgenic plants), probably by hydrolysing their substrates as structural components in the fungal cell wall. Group PR-4 is the less studied, and in tobacco contains four members of 13-14.5 kDa of unknown activity and function. Group PR-5 contains acidic-neutral and very basic members with extracellular and vacuolar localization, respectively, and all members show sequence similarity to the sweet-tasting protein thaumatin. Several members of the PR-5 group from tobacco and other plant species were shown to display significant in vitro activity of inhibiting hyphal growth or spore germination of various fungi probably by a membrane permeabilizing mechanism.(ABSTRACT TRUNCATED AT 400 WORDS)

Chitinases↗
PubMed1990

Cloning of cDNAs for human phosphoribosylpyrophosphate synthetases 1 and 2 and X chromosome localization of PRPS1 and PRPS2 genes.

Cloned cDNAs representing the entire, homologous (80%) translated sequences of human phosphoribosylpyrophosphate synthetase (PRS) 1 and PRS 2 cDNAs were utilized as probes to localize the corresponding human PRPS1 and PRPS2 genes, previously reported to be X chromosome linked. PRPS1 and PRPS2 loci mapped to the intervals Xq22-q24 and Xp22.2-p22.3, respectively, using a combination of in situ chromosomal hybridization and human x rodent somatic cell panel genomic DNA hybridization analyses. A PRPS1-related gene or pseudogene (PRPS1L2) was also identified using in situ chromosomal hybridization at 9q33-q34. Human HPRT and PRPS1 loci are not closely linked. Despite marked cDNA and deduced amino acid sequence homology, human PRS 1 and PRS 2 isoforms are encoded by genes widely separated on the X chromosome.

Animals↗