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Biomedical subjects

R Pierce

Publications and source records attributed to R Pierce.

At least 19 recordsLinked to original sources
PubMed1999

UVB irradiation stimulates deposition of new elastic fibers by modified epithelial cells surrounding the hair follicles and sebaceous glands in mice.

UVB irradiation stimulates the synthesis of elastin in the skin of humans and experimental animals. In this study we localized the site and the cells that are responsible for the synthesis of murine dermal elastic fibers. SKH-1 hairless mice were irradiated with UVB and the skin removed for light microscopy, electron microscopy, in situ hybridization, immunohistochemistry, and biochemical studies. In response to chronic low doses of UVB there was an initial moderate increase in tropoelastin mRNA in the papillary dermis. By contrast, there was a continuous marked elevation of collagen alpha1(I) message localizing to sites of inflammatory cell influx throughout the upper and lower dermis. After 25 wk of UV irradiation there was a 2-fold increase in skin elastin, yet total collagen remained unchanged. Serial desmosine analysis from en face sections indicated the increase in elastin content was due to dermal elastic fibers, an increase in the size and number of the dermal cysts, and an increase in subpanniculus elastic fibers. Elastin stains of en face sections suggested that the elastic fibers in the upper dermis were exclusively derived from cells lining the epithelial root sheath and sebaceous glands. In response to UV irradiation, the elastic fibers increased in number and size, wrapping around these structures and aligning in both directions as long fibers parallel to the body axis. Electron micrographs indicated that modified epithelial cells in close proximity to the flattened epithelial cells that encircled the root sheath and sebaceous glands were the source of the elastic fibers.

Animals↗
PubMed1998

Activity of respiratory pump and upper airway muscles during sleep onset.

Ventilation decreases at sleep onset. This change is initiated abruptly at alpha-theta electroencephalographic transitions. The aim of this study was to determine the contributions of reduced activity in respiratory pump muscles and upper airway dilator muscles to this change. Surface electromyograms over the diaphragm (Di) and intercostal muscles and fine-wire intramuscular electrodes in genioglossus (GG) and tensor palatini (TP) muscles were recorded in nine healthy young men. It was shown that phasic Di and both phasic and tonic TP activities were lower during theta than during alpha activity. Breath-by-breath analysis of the changes at alpha-theta transitions during the sleep-onset period showed a number of changes. At alpha-theta transitions, phasic activity of Di, intercostal, and GG muscles fell and rose again, and phasic and tonic activities of TP fell and remained at low levels during theta. With a state transition from theta to alpha, the phasic and tonic activities of the Di, GG, and TP increased dramatically. It is now clear that the fall in ventilation that occurs with sleep is related to a fall in activities of both upper airway dilator muscles and respiratory pump muscles.

Adolescent↗
PubMed1998

Duplex-directed vena caval filter placement: report of initial experience.

BACKGROUND: Fluoroscopy, cost, and patient transport contribute to difficulties occasionally associated with the placement of vena caval filters. Follow-up data in the literature document the use of duplex ultrasonography in visualizing the filter and determining caval patency. Filter placement at the bedside or in the vascular laboratory with duplex ultrasonography may simplify this common procedure. We have attempted to define the feasibility of this method. METHODS: Patients referred to the vascular surgery service for vena caval interruption were evaluated for ability to visualize the renal veins and inferior vena cava. Location of renal veins, maximum diameter of the vena cava, and presence or absence of thrombus were documented. If visualization was adequate, placement was performed at the bedside for patients in intensive care or in the vascular laboratory for nonmonitored patients. The initial 10 patients and subsequent patients in whom there was a question of adequate deployment underwent completion abdominal roentgenography. Patient follow-up was difficult. Duplex ultrasonography was used to assess migration, thrombus adherent to the filter, and vena caval patency. Patients in whom filter placement was prophylactic were given anticoagulants at the discretion of the primary physician. Inadequate visualization or vena caval size greater than 28 mm prompted fluoroscopic placement of the vena caval filter, because only Greenfield titanium filters were used in the study. RESULTS: Twenty-nine patients were referred for vena caval interruption. Inadequate visualization occurred in four obese patients, and filters were placed by fluoroscopy. There were no vena caval measurements greater than 24 mm. Twenty-five filters were placed without technical difficulty. One filter tilted into the right renal vein, requiring a suprarenal filter placed by fluoroscopy. Patient retrieval for follow-up has been difficult, but by ultrasonography there has been one vena caval thrombosis and no major filter migration. There have been no reported pulmonary emboli other than the one patient with initial tilt of the filter. CONCLUSIONS: Placement of vena caval filters is feasible with duplex ultrasonography. Visualization is the only limiting condition to placement and occurs rarely. Reducing the need for fluoroscopy, lowering costs, and not needing to transport the critically ill patient support the use of this system. Intravascular ultrasonography in selected patients may eliminate the need for fluoroscopic placement of vena caval filters.

Fluoroscopy↗
PubMed1997

Ligand binding was acquired during evolution of nuclear receptors.

The nuclear receptor (NR) superfamily comprises, in addition to ligand-activated transcription factors, members for which no ligand has been identified to date. We demonstrate that orphan receptors are randomly distributed in the evolutionary tree and that there is no relationship between the position of a given liganded receptor in the tree and the chemical nature of its ligand. NRs are specific to metazoans, as revealed by a screen of NR-related sequences in early- and non-metazoan organisms. The analysis of the NR gene duplication pattern during the evolution of metazoans shows that the present NR diversity arose from two waves of gene duplications. Strikingly, our results suggest that the ancestral NR was an orphan receptor that acquired ligand-binding ability during subsequent evolution.

Amino Acid Sequence↗
PubMed1997

Local transient induction of inflammatory cytokines after intranasal administration of recombinant Bordetella pertussis.

Inflammatory cytokines have been described to play a critical role in the orientation and amplification of the IgA immune response. In this study, we show that the intranasal administration of a Bordetella pertussis strain expressing the protective antigen glutathione-S-transferase of Schistosoma mansoni (Sm28GST) induced an inflammatory response in the lungs of mice, characterized by the production of inflammatory cytokines, such as Tumor Necrosis Factor alpha, Interleukin-6 and Transforming-Growth Factor beta. The production and the secretion of these cytokines in lung tissues were early and transient. Their presence was observed only during the first week after administration despite the persistence of the bacteria for 1 month. Two weeks after inoculation, Interleukin-10 secretion was detected in the lungs, which could explain the decrease in the production of inflammatory cytokines. These inflammation-regulating cytokines, induced in the lungs by the presence of the bacterial vector, could be part of the process generating the local immune response, in particular the anti-Sm28GST IgA response.

Administration, Intranasal↗
PubMed1997

Developmental skills of children with spastic diplegia: functional and qualitative changes after selective dorsal rhizotomy.

OBJECTIVE: This study examined changes in muscle tone, passive range of motion, stability, and mobility in developmental skills at 6 months and 1 year after selective dorsal rhizotomy (SDR). DESIGN: Prospective outcome study of a consecutive sample. SETTING: Private children's hospital. PATIENTS: Twenty-six children with spastic diplegia: 13 independent and 13 dependent ambulators (assistive devices). RESULTS: A decrease in spasticity was seen at 6 months after SDR, with no further decrease at 1 year. Increases in passive range of motion of the hip and ankle were seen at 6 months after SDR. The ability to assume and maintain developmental positions with improved alignment and stability was seen more frequently at 6 months after SDR, whereas an improvement in the ability to perform transitional movements was seen more frequently at 1 year after SDR. CONCLUSION: SDR decreases spasticity and increases lower extremity range of motion in children with spastic diplegia and appears to be associated with the ability to assume a greater variety of developmental positions with improved alignment, thus greater stability. Improvements in the ability to perform difficult transitional movements at 1 year after SDR are most likely the result of the combined effect of maturation, SDR, and intensive therapeutic intervention.

Activities of Daily Living↗
PubMed1997

The HLA-A*0201-restricted H-Y antigen contains a posttranslationally modified cysteine that significantly affects T cell recognition.

A peptide recognized by two cytotoxic T cell clones specific for the human minor histocompatibility antigen H-Y and restricted by HLA-A*0201 was identified. This peptide originates from SMCY, as do two other H-Y epitopes, supporting the importance of this protein as a major source of H-Y determinants in mice and humans. In naturally processed peptides, T cells only recognize posttranslationally altered forms of this peptide that have undergone modification of a cysteine residue in the seventh position. One of these modifications involves attachment of a second cysteine residue via a disulfide bond. This modification has profound effects on T cell recognition and also occurs in other class I MHC-associated peptides, supporting its general importance as an immunological determinant.

Animals↗
PubMed1997

Cost-effective method for bedside insertion of vena caval filters in trauma patients.

BACKGROUND: The need for patient transport for inferior vena cava (IVC) filter placement impacts patient safety, comfort, charges, and nursing care. Bedside, ultrasound-guided IVC filter placement may offer an acceptable, cost-effective alternative. METHODS: Prospective cohort study of 55 consecutive trauma patients requiring IVC filter placement. During a 13-month period (August of 1995-September of 1996), patients meeting criteria for IVC filter were evaluated. Complications were recorded, and the potential financial savings were determined. RESULTS: Of 3,172 trauma admissions, 55 patients met IVC filter criteria and 49 patients had IVC filters placed under ultrasound guidance. In six patients (10.9%), ultrasound guided filter placement failed. There were four complications in four patients (8.2%). Over 13 months, charges were reduced by $69,800 when compared with radiology suite placement and $118,300 when compared with operative placement. CONCLUSIONS: Ultrasound guided, bedside placement of IVC filters is a safe, cost-effective method of pulmonary embolism prophylaxis in select trauma patients.

Adolescent↗
PubMed1997

Product of the Schistosoma mansoni glutathione peroxidase gene is a selenium containing phospholipid hydroperoxide glutathione peroxidase (PHGPx) sharing molecular weight and substrate specificity with its mammalian counterpart.

In the blood fluke Schistosoma mansoni a functionally active, monomeric, phospholipid hydroperoxide glutathione peroxidase (PHGPx) has been purified and characterized. This enzyme contains a catalytically active selenocysteine. The protein has been shown to be the product of a cloned gene, previously referred to as a glutathione peroxidase gene. S. mansoni PHGPx has been found 5 times more abundant in female than in male worm extract. As in vertebrate PHGPx, homology alignment indicates that the residues involved in the glutathione binding by the tetrametric cellular glutathione peroxidase are mutated in the S. mansoni enzyme. Thus, this aspect appears a landmark of the PHGPx-type of glutathione peroxidases, which might be of functional relevance.

Amino Acid Sequence↗
PubMed1996

A selenium-containing phospholipid-hydroperoxide glutathione peroxidase in Schistosoma mansoni.

The 100000Xg supernatant parasite platyhelminth Schistosoma mansoni exhibits a glutathione peroxidase activity with the substrate phosphatidylcholine hydroperoxide. Purification yielded a protein of 20 kDa molecular mass both on gel filtration column chromatography and SDS/PAGE, thus suggesting that S. mansoni expresses a protein similar to the mammalian selenoenzynic phospholipid-hydroperoxide glutathione peroxidase. Kinetic analysis and substrate specificity corroborated this assumption, the second-order rate constants for the oxidation of the ground-state enzyme (k+1) being higher with phosphatidylcholine hydroperoxide than with other peroxide substrates, such as cumene liydroperoxide or H2O2, and quantitatively similar to those of mammalian phospholipid-hydroperoxide glutathione peroxidase. Partial sequencing of the protein and selenium measurement by neutron activation analysis established that the purified peroxidase corresponded to the product of the S. mansoni gene previously reported and supposed to encode a selenium-containing glutathione peroxidase [Roche, C., Williams, D. L., Khalife, J., LePresle, T., Capron, A. & Pierce, R. J. (1994) Cloning and characterization of gene encoding Schistosoma mansoni glutathione peroxidase, Gene 138, 149 - 152]. S. mansoni thus contains a scienoperoxidase sharing molecular mass, catalytic efficiency and substrate specificity with phospholipid-hydroperoxide glutathione peroxidase, dismantling the concept that those enzymes are unique to vertebrate organisms.

Amino Acid Sequence↗
PubMed1996

Update on lung cancer.

Lung cancer is common, largely smoking related and thus preventable. Focal non small cell disease is surgically resectable but presentation with mediastinal and metastatic disease is common and has a poor prognosis. Small cell lung cancer is chemosensitive but has a very poor prognosis. Widespread screening programs are not currently considered cost-effective. New preventive and therapeutic approaches are the way forward and a multidisciplinary approach is clearly needed.

Humans↗
PubMed1996

Temephos distribution and persistence in a southwest Florida salt marsh community.

The distribution and persistence of the mosquito larvicide temephos was monitored throughout an intertidal salt marsh community in southwest Florida following routine aerial applications of Abate 4-E (43% temephos) from 1988 through 1993. Temephos was found to be more highly concentrated in the surface water microlayer than in mid-depth water, exhibiting a mean of 330 micrograms/liter at the surface and 12 micrograms/liter at mid-depth from 1 fl. oz./acre applications and 120 micrograms/liter in the surface and 4.5 micrograms/liter in mid-depth water for 0.5 fl. oz./acre applications. Concentrations at both surface and mid-depth diminished rapidly within the first 24 hours. Mangrove leaves provided the most persistent reservoir for temephos, remaining more than 7 days. Temephos residues also were observed in select salt marsh organisms, including the sheepshead minnow (Cyprinodon variegatus), adult fiddler crabs (Uca rapax) and the ribbed mussel (Geukensia sp.).

Florida↗
PubMed1994

Brief upper airway dysfunction.

We have analysed the clinical manifestations of nine patients with brief upper airway dysfunction (BUAD) who attended the thoracic department of a major teaching hospital between 1987 and 1991. Episodes of BUAD developed within 1-4 months of presentation in three patients but were undiagnosed for 2.5-12.5 years in six. The mean age at onset was 51 years ranging from 37 to 66 years. The episodes occurred at irregular intervals. They lasted approximately 1-5 min, were frightening and consisted of an initial phase of obstructive apneoa lasting a few seconds to 2 min and a second phase of respiratory distress with inspiratory stridor lasting 1-4 min. Daytime episodes occurred in all and at night in five, waking three of the patients from sleep. In most instances, throat irritability triggered the episodes which were often preceded by cough. Potential causes of throat irritability included respiratory tract infection, allergy, oesophageal reflux and obstructive sleep apnoea. After treatment of throat irritability BUAD has ceased for at least a year in six of the eight with adequate follow-up. In conclusion, BUAD has characteristics clinical features which should enable it to be recognized more frequently, ensuring successful management.

Adult↗
PubMed1994

Characterization and localization of Schistosoma mansoni calreticulin Sm58.

Recombinant Schistosoma mansoni calreticulin (SmCaR) was expressed in Escherichia coli, using the glutathione S-transferase fusion protein, and its Ca(2+)-binding capacity was determined. Results obtained by a 45Ca2+ overlay technique showed that Ca(2+)-binding site(s) were present in the recombinant CaR indicating that proper folding of the protein was obtained using this system. An antiserum raised against the recombinant SmCaR showed that the native protein (Sm58) was expressed in all stages of the life-cycle from cercariae to the adult worm and in the egg. However, SmCaR seems to be a developmentally regulated protein whose expression can be used to study the post-transformational differentiation of the schistosomulum. Localization of SmCaR demonstrated that the majority of SmCaR was expressed in the epithelia of the digestive duct and in the genital organs. These results suggest that SmCaR, by regulating the Ca2+ concentration, may play an important role during cell proliferation. Finally the presence of SmCaR in miracidia and in the genital organs suggests that the antibody response directed against this protein could interfere in egg production.

Amino Acid Sequence↗