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J Davis

Publications and source records attributed to J Davis.

At least 73 records · Page 4Linked to original sources
PubMed2000

Inhibitors of tyrosine phosphatases block angiotensin II inhibition of Na(+) pump.

To determine how angiotensin II inhibits the Na(+) pump (Na(+), K(+)-ATPase) in rat zona glomerulosa, we selectively blocked signaling proteins that could be activated by the angiotensin AT(1) receptor and known to affect Na(+) pump activity. Inhibitors of protein kinase C [calphostin C (1 microM); staurosporine (1 microM)], phospholipase A(2) [arachidonyl triflouromethyl ketone (25 microM); quinacrine (75 microM)], diacylgycerol lipase [RHC-80267 (5 microM)], and tyrosine phosphorylation [tyrphostin 47 (100 microM)] had no effect on angiotensin II inhibition of the Na(+) pump. On the other hand, inhibitors of tyrosine phosphatases [phenylarsine oxide (5 microM) and 4-bromotetramisole oxalate (100 microM)] blocked angiotensin II inhibition, where as inhibitors of serine/threonine phosphatases [okadaic acid (1 microM) and microcystin (1.5 microM)] did not. Thus, angiotensin II inhibition of the Na(+) pump may in part be mediated by a tyrosine phosphatase.

Angiotensin II↗
PubMed2000

Rapid determination of COL2A1 mutations in individuals with Stickler syndrome: analysis of potential premature termination codons.

Stickler syndrome is one of the milder phenotypes resulting from mutations in the gene that encodes type-II collagen, COL2A1. All COL2A1 mutations known to cause Stickler syndrome result in the formation of a premature termination codon within the type-II collagen gene. COL2A1 has 10 in-frame CGA codons, which can mutate to TGA STOP codons via a methylation-deamination mechanism. We have analyzed these sites in genomic DNA from a panel of 40 Stickler syndrome patients to test the hypothesis that mutations that cause Stickler syndrome preferentially occur at these bases. Polymerase chain reaction (PCR) amplification of genomic DNA containing each of the in-frame CGA codons was done by one of two methods: either using primers that amplify DNA that includes the CGA codon, or using allele-specific primers that either amplify normal sequence containing a CGA codon or amplify a mutant sequence containing a TGA codon. Analysis of PCR products by restriction endonuclease digestion or sequencing demonstrated the presence of a normal or mutated codon. TGA mutations were identified in eight patients, at five of the 10 in-frame CGA codons. The identification of these mutations in eight of 40 patients demonstrates that these sites are common sites for mutations in individuals with Stickler syndrome and, we propose, should be analyzed as a first step in the search for mutations that result in this disorder.

Alleles↗
PubMed2000

Evidence for gelsolin as a corneal crystallin in zebrafish.

We have shown that gelsolin is one of the most prevalent water-soluble proteins in the transparent cornea of zebrafish. There are also significant amounts of actin. In contrast to actin, gelsolin is barely detectable in other eye tissues (iris, lens, and remaining eye) of the zebrafish. Gelsolin cDNA hybridized intensely in Northern blots to RNA from the cornea but not from the lens, brain, or headless body. The deduced zebrafish gelsolin is approximately 60% identical to mammalian cytosolic gelsolin and has the characteristic six segmental repeats as well as the binding sites for actin, calcium, and phosphatidylinositides. In situ hybridization tests showed that gelsolin mRNA is concentrated in the zebrafish corneal epithelium. The zebrafish corneal epithelium stains very weakly with rhodamine-phalloidin, indicating little F-actin in the cytoplasm. In contrast, the mouse corneal epithelium contains relatively little gelsolin and stains intensely with rhodamine-phalloidin, as does the zebrafish extraocular muscle. We propose, by analogy with the diverse crystallins of the eye lens and with the putative enzyme-crystallins (aldehyde dehydrogenase class 3 and other enzymes) of the mammalian cornea, that gelsolin and actin-gelsolin complexes act as water-soluble crystallins in the zebrafish cornea and contribute to its optical properties.

Amino Acid Sequence↗
PubMed2000

Buoyant magnetic flux tubes enhance radiation in Z pinches

In numerous experiments, magnetic energy coupled to strongly radiating Z-pinch plasmas exceeds the thermalized kinetic energy, sometimes by a factor of 2-3. We demonstrate that the enhanced energy coupling may be due to the buoyancy rise of toroidal magnetic flux tubes converging to the axis through the unstable pinch plasma. We derive an explicit formula for the enhanced dissipation rate and apply this formula to reconsider an old problem of power balance in a steady-state Z pinch, and then to analyze a new challenge of producing K-shell 3 to 10 keV radiation in long-pulse Z-pinch implosions.

Journal Article↗
PubMed2000

Increased levels of leukemia inhibitory factor mRNA in muscular dystrophy and human muscle trauma.

Leukemia inhibitory factor (LIF) is an important muscle trauma factor both after crush injury and in the mdx mouse dystrophy model. It is important to establish which growth factors have a role in human muscle regeneration due to potential clinical therapeutic applications. As there is limited information concerning LIF expression in human muscle, we investigated the relative levels of LIF messenger ribonucleic acid (mRNA) in human muscle injury. Semiquantitative reverse transcriptase followed by polymerase chain reaction was used to amplify LIF message. We found that although LIF mRNA is expressed in low levels in control muscle, a sevenfold increase occurred after orthopedic muscle trauma and a marked 19-fold increase in dystrophic muscle (P < 0.002). These results indicate that LIF mRNA is upregulated in surgical and especially medical muscle injury with repeated myonecrosis. Muscle growth factors such as LIF may assist in future muscle rehabilitation after injury.

Adolescent↗
PubMed2000

Sonoelectroanalytical detection of lead at a bare copper electrode.

The sonochemically facilitated, mercury free detection of Pb2+ at a copper electrode has been investigated as a means of simplifying the quantification of this important analyte and to minimise the interference of copper ion. The procedure relies upon maximising the formation of Pb-Cu intermetallic compounds leading to the emergence of a single, easily quantifiable stripping signal. Linear responses to Pb2+ were obtained with a sensitivity comparable to that obtained at a bare glassy carbon electrode. Interference from Cu2+, Zn2+ and Cd2+ was assessed on the copper electrode with no appreciable change in the Pb2+ voltammetric profile observed. In contrast, bare glassy carbon showed a significant change in Pb2+ voltammetric profile as Cu2+ was added, due to the formation of intermetallic species.

Calibration↗
PubMed2000

The modern National Kidney Foundation: broad scope, clear vision, better lives.

The mission of the National Kidney Foundation is very broad, going well beyond what its name implies. The Foundation works for, cares about, and represents millions of Americans, from the child who wets the bed to the diabetic with hypertension to the grandfather on dialysis. It is dedicated to making lives better through a variety of educational programs for patients and their families as well as physicians, social workers, nurses, dietitians, technicians, administrators, and clinical and transplant coordinators. It supports research, promotes organ and tissue donation, provides direct services to patients, and advocates for patients through public policy and legislative initiatives. Its programs aid people at risk of kidney and urinary tract disease, individuals affected by these diseases, living organ donors and families of donors, and recipients of all types of lifesaving organ and tissue transplants.

Adult↗
PubMed2000

Proapoptotic functions of cytotoxic lymphocyte granule constituents in vitro and in vivo.

Recent advances in our understanding of cytolytic effector mechanisms include the partial characterization of caspase-independent apoptotic pathways triggered by granzymes, a realization of the vital importance of perforin and granzymes in the defence against certain virus infections in vivo and the first description of hereditary immunodeficiency due to disordered perforin expression in humans.

Animals↗
PubMed2000

The Scottish and Manchester randomised trial of neo-adjuvant chemotherapy for advanced cervical cancer.

204 eligible patients were entered into a multicentre randomised trial of neo-adjuvant chemotherapy prior to radical radiotherapy. The aim of this study was to assess whether there was any survival advantage in patients undergoing chemotherapy and radiotherapy compared with those given radiotherapy alone. Patients were aged up to 70 years, performance status 0-1/2, with bulky stage IIb, stage III or stage IVa squamous or adenosquamous carcinoma. Three cycles of methotrexate 100 mg/m2 and cisplatin 50 mg/m2 were given at 2-weekly intervals before radical radiotherapy. 104 eligible patients received the combination treatment and 100 radiotherapy only. The two arms of the study were well balanced for tumour and patient characteristics. The response rate to chemotherapy was 49%, 33% of patients in the radiotherapy (XRT) alone arm and 45% of the combination arm were clinically free of tumour at the end of treatment. The median follow-up for surviving patients is 5.4 years (range: 11 months-8 years) and 84% have been followed-up for more than 4 years. 134 patients have died (68 XRT only, 66 combined arm). The median survival RT alone was 111 weeks (95% confidence interval (CI) 72-151 weeks), combination arm 125 weeks (95% CI 79-170 weeks). The estimated death ratio is 0.79 (P = 0.19, 95% CI 0.56-1.12). The estimated 3-year survival is 40% (95% CI 30-50%) RT only compared with 47% (95% CI 37-57%) in the combination arm. Acute and late toxicity of radiotherapy was not increased by the addition of chemotherapy.

Adult↗
PubMed2000

Red-carpet rodent care: making the most of dollars and sense in the animal facility.

Cutting-edge biomedical research programs have entered an era in which phenotypic characterizations for genetically altered rodents can facilitate appropriate care. The veterinary care requirements necessary to support such animal models can include the procedures already adapted as standard practice in companion animal hospitals, and can decrease data variability while increasing survival rates.

Journal Article↗
PubMed2000

Air flight disaster, posttraumatic stress, and postventive rescue and response: the aftermath of the San Diego PSA 182 plane crash recovery operation, 20 years on.

San Diego in 1978 was the scene of one of the USA's most tragic and traumatic air flight disasters, when an inbound Boeing 727 collided with a small private Cessna 172. The collision occurred in the vicinity of North Park, a suburb of San Diego. All aircraft occupants were killed or injured and many residents were injured. The wreckage was mainly concentrated in an area about the size of a city block, in a temperature of 100 degrees F or more. The whole experience was unlike anything any of the professionals involved had been prepared for, and beyond anything the civilians involved could have imagined. Many sought out intervention and help and counselling, and this paper examines the implications of the event 20 years on.

Accidents, Aviation↗
PubMed2000

Effect of single versus multiple courses of antenatal corticosteroids on maternal and neonatal outcome.

OBJECTIVE: Treatment of pregnant mothers with a single course of antenatal corticosteroids significantly reduces neonatal mortality and morbidity. Multiple weekly courses are often given. However, the safety and efficacy of repeated courses of antenatal corticosteroids have not been adequately studied. STUDY DESIGN: A retrospective study was performed for 609 mothers and their 713 infants who were treated with 1 to 12 courses of antenatal corticosteroids. Data for 369 singleton preterm infants born at < or =34 weeks' gestation, 210 multiple gestations, and 134 infants delivered at > or =35 weeks' gestation were analyzed separately. RESULTS: The incidence of respiratory distress syndrome was 45% for single-course and 35% for multiple-course groups (P =.005; odds ratio, 0.44; 95% confidence interval, 0.25-0.79). The multiple-course group also had significantly less patent ductus arteriosus (20% vs 13%; P =.016). Incidence of death before discharge and other neonatal morbidities were similar. The multiple-course group had a reduction of 0.46 +/- 0.19 cm in head circumference at birth (P =.013) when adjusted for gestational age and preeclampsia. The 2 groups had similar birth weights. Infants born at > or =35 weeks' gestation, multiple-gestation infants, and infants who were born >7 days after the last corticosteroid dose had similar outcomes, regardless of the number of courses they received. Mothers treated with multiple courses compared with a single course had a significantly higher incidence of postpartum endometritis (P =.013), even though they had a lower incidence of prolonged rupture of membranes (24% vs 33%, P =.06) and similar cesarean delivery rates. CONCLUSION: Exposure to multiple courses of antenatal corticosteroids compared with a single course resulted in a significant reduction in the incidence of respiratory distress syndrome in singleton preterm infants delivered within a week of the last corticosteroid dose. This was associated with a reduction in birth head circumference and an increased incidence of maternal endometritis. Whether the potential benefits of repeated therapy clearly outweigh the risks will ultimately be determined in randomized prospective controlled trials.

Adrenal Cortex Hormones↗
PubMed2000

Quantitative trait loci and candidate gene mapping of bud set and bud flush in populus.

The genetic control of bud phenology in hybrid poplar was studied by mapping quantitative trait loci (QTL) affecting the timing of autumn bud set and spring bud flush. The founders of the mapping pedigree were collected from widely separated latitudes to maximize segregating variation for dormancy-related traits in the F(2) generation-the female Populus trichocarpa parent is from Washington State (48 degrees N) and the male P. deltoides parent is from Texas (31 degrees N). Bud set and bud flush timing were measured on the F(2) generation in a replicated clonal field trial. Using a linkage map constructed of AFLP and microsatellite markers, three QTL controlling bud set and six QTL controlling bud flush were detected. Additionally, five candidate genes believed to be involved in perception of photoperiod (PHYB1, PHYB2) or transduction of abscisic acid response signals (ABI1B, ABI1D, and ABI3) were placed on the QTL map. PHYB2 and ABI1B were found to be coincident with QTL affecting bud set and bud flush.

Base Sequence↗
PubMed2000

Corrugator supercilii muscle resection and migraine headaches.

This study was conducted to determine whether there is an association between the removal of the corrugator supercilii muscle and the elimination or significant improvement of migraine headaches. Questionnaires were sent to 314 consecutive patients who had undergone corrugator supercilii muscle resection during endoscopic, transpalpebral, or open forehead rejuvenation procedures. The patients were queried as to whether they had a history of migraine headaches and, if so, whether the headaches significantly improved or disappeared after surgery. If the answer was affirmative, then the patients were further questioned about the duration of the improvement or cessation of the headaches and the relationship to the timing of the surgery. After an initial evaluation of the completed questionnaires, a telephone interview was conducted to confirm the initial answers and to obtain further information necessary to ensure that the patients had a proper diagnosis based on the International Headache Society criteria for migraine headaches. The charts of the patients who had migraine headaches were studied to ascertain and classify the type of surgery they had undergone. Patient demographics were reviewed, and the results were statistically analyzed. Of the 314 patients, 265 (84.4 percent) either responded to the questionnaire, were interviewed, or both responded to the questionnaire and were interviewed. Of this group, 16 patients were excluded because of the provision of insufficient information to meet the International Headache Society criteria, the presence of organic problems, and other exclusions mandated by study design. Thirty-nine (15.7 percent) of the remaining 249 patients had migraine headaches that fulfilled the Society criteria. Thirty-one of the 39 (79.5 percent) with preoperative migraine noted elimination or improvement in migraine headaches immediately after surgery (p < 0.0001; McNemar), and the benefits lasted over a mean follow-up period of 47 months. When the respondents with a positive history of migraine headaches were further divided, 16 patients (p < 0.0001; McNemar) noticed improvement over a mean follow-up period of 47 months, and 15 (p < 0.0001; McNemar) experienced total elimination of their migraine headaches over a mean follow-up period of 46.5 months. When divided by migraine headache type, 29 patients (74 percent) had nonaura migraine headaches. Of these patients, the headaches disappeared in 11 patients, improved in 13 patients, and did not change in five patients (p < 0.0001). Ten patients experienced aura-type headaches, which disappeared or improved in seven of the patients and did not change in three of the patients (p < 0.0001). This study proves for the first time that there is indeed a strong correlation between the removal of the corrugator supercilii muscle and the elimination or significant improvement of migraine headaches.

Adult↗