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Biomedical subjects

T Davis

Publications and source records attributed to T Davis.

At least 37 records · Page 2Linked to original sources
PubMed1989

The undiluted message in psychiatry: is medical rounding valuable?

The present research investigated whether psychiatric inpatients would recall, without distortion, the key components of information presented to them during morning rounds. Over the 4 weeks of the study, the messages of rounding psychiatrists were recorded and then compared with the recollections of 16 subjects recorded several hours later. Analysis showed that undistorted recall of messages occurred significantly more often than distorted recall or no recall. These results suggest that there is a possible value for undiluted messages in medical rounding in the inpatient psychiatric context when given as an adjunct to psychotherapeutic and psychopharmacological interventions.

Humans↗
PubMed1989

Do inhibitors of lipoxygenase and cyclooxygenase block neonatal hypoxic pulmonary vasoconstriction?

Lipoxygenase products have been suggested as mediators of the hypoxic pulmonary pressor response in newborn animals. Data supporting this suggestion are equivocal, since lipoxygenase and leukotriene receptor antagonists that have been used may produce vasodilation because of phosphodiesterase inhibition. We used a leukotriene receptor antagonist L 649923, which appears not to have smooth muscle relaxant activity. L 649923 blocks pressor responses to leukotriene D4 (LTD4) without diminishing the pressor response to hypoxia. Also, BW 755C did not block the pressor response to hypoxia in newborn sheep and goats, whereas the pressor response to LTD4 (75 ng/kg) was depressed significantly. In newborn sheep there was an augmented response to hypoxia with BW 755C, which is consistent with cyclooxygenase inhibition. Finally, the thromboxane receptor antagonist SQ 29548 was investigated in both species. With this agent the pressor response to LTD4 in contrast to that of hypoxia was completely inhibited. We conclude that thromboxanes are involved in the pressor response to LTD4 in newborn lambs and goats. These data do not support the view that leukotrienes are involved in the ovine or caprine neonatal pulmonary pressor response to hypoxia.

4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyraz↗
PubMed1989

Endoscopic injection therapy for acute upper GI bleeding.

In summary, we have found this technique to be useful in patients in whom coagulation therapy is not possible or effective. It must still be considered a technique which is undergoing evaluation. Prospective randomized trials comparing this therapy with other currently available therapies such a electrocoagulation, laser and conservative management must be completed to firmly define its place in treatment strategy for acute upper GI bleeding.

Aged↗
PubMed1989

Occurrence of Culex erythrothorax in southeastern Colorado and report of virus isolations from this and other mosquito species.

Significant numbers of Culex erythrothorax were collected during arbovirus surveillance in 1987 and 1988 at Las Animas, Bent County, on the high plains of southeastern Colorado. This finding extends the range of this species to the eastern side of the Rocky Mountains. The isolation of western equine encephalitis virus in 1988 from both Cx. tarsalis and Cx. erythrothorax suggests that the latter also may be involved in the endemic cycle of this virus in the area. St. Louis encephalitis, Hart Park, Turlock, and a Bunyamwera group virus were also isolated from the mosquitoes collected.

Aedes↗
PubMed1988

Nucleotide sequence of the mannitol (mtl) operon in Escherichia coli.

The nucleotide sequence of the known portions of the mannitol operon in Escherichia coli (mtlOPAD) has been determined. Both the operator-promoter region and the intercistronic region between the mtlA and mtlD genes (encoding the mannitol-specific Enzyme II of the phosphotransferase system and mannitol-1-phosphate dehydrogenase, respectively) show parallels with corresponding regions of the glucitol (gut) operon, but neither the mtlA nor the mtlD gene products show obvious homology with the corresponding gene products of the glucitol operon. Five potential cyclic AMP receptor protein binding sites were identified in the mtlOP region, all showing near identity with the consensus sequence. Four regions of dyad symmetry (four to seven bases in length), serving as potential repressor binding sites, overlap with the potential cyclic AMP receptor protein binding sites. Repetitive extragenic palindromic (REP) sequences, forming stem-loop structures in the intercistronic region between mtlA and mtlD and following the mtlD gene were identified. Probable terminator sequences were not found in any of these three regulatory regions. Mannitol-1-phosphate dehydrogenase exhibits two overlapping, potential NAD+ binding sites near the N-terminus of the protein. Computer techniques were used to analyse the mtlD gene and its product.

Amino Acid Sequence↗
PubMed1987

CpG deficiency, dinucleotide distributions and nucleosome positioning.

The dinucleotide CpG is deficient in (A + T)-rich regions of vertebrate DNA in both coding and non-coding sequences and there is a corresponding increase above expectation in the occurrence of TpG and CpA. By contrast in (G + C)-rich regions no deficiency of CpG is found. Such (G + C)-rich sequences, containing the expected number of CpG dinucleotides, alternate along the genome with (A + T)-rich sequences which have a lower than expected CpG content. The G + C content of vertebrate DNA can oscillate with a period of 150-200 bp and this may be a factor in positioning nucleosomes. The role of mutagenesis in loss of CpG and increase of A + T, particularly in non-coding regions, is discussed.

Base Composition↗
PubMed1987

Pulmonary aspergillosis: unusual radiographic appearance.

Three cases of pulmonary aspergillosis are reported in which a seldom-mentioned radiographic feature was seen, namely, a stable, well-defined nodule or mass. The diagnosis of aspergillosis was based on results of transthoracic needle aspiration biopsy. Computed tomographic scans obtained before biopsy revealed no evidence of underlying cavitary disease. Two patients had hemoptysis. The nodule in the third patient was found on a routine chest radiograph.

Aged↗
PubMed1987

Glycogen-rich clear cell carcinoma of the urethra: an ultrastructural study.

A 49-year-old black woman developed a urethral glycogen-rich clear cell carcinoma. She was treated with anterior pelvic exenteration. The resected lymph nodes, vagina, uterine cervix, endometrium, ovaries, and urinary bladder were free of neoplasm. Histologically the neoplasm consisted of clear cells growing in sheets and occasional papillary structures. In some areas, hobnail cells were present. Ultrastructurally, the cells had apical caps, short microvilli, and complex cell bases, and contained abundant glycogen. These features were identified in one, but not the other of two previously reported cases. Because glycogen-rich clear cell carcinomas of the lower urinary tract do not resemble ultrastructurally mesonephric remnants or carcinomas known to arise from them, these glycogen-rich clear cell carcinomas should not be called "mesonephromas" as has been the practice.

Adenocarcinoma↗
PubMed1987

Epizootic vesicular stomatitis in Colorado, 1982: epidemiologic and entomologic studies.

An epizootic of vesicular stomatitis (VS) caused by the New Jersey serotype of VS virus affected livestock and humans in 14 western states in 1982-1983. Epidemiological observations were made on at least 10% of the cattle in 4 dairy herds that were located in the vicinity of Grand Junction, Colorado. High rates of neutralizing antibody to the New Jersey serotype were seen in all cattle regardless of whether livestock in the dairy had clinical VS or a decrease in mild production. Antibody titers remained high in these cattle for as long as 2 years after the epizootic. No virus isolations were made from 32 humans with clinical signs compatible with viral disease. Entomological information was obtained during the epizootic from 23 premises in northwestern Colorado. Insect collections yielded 4 isolates from Culicoides spp. midges, 2 from C. variipennis, and 1 each from C. stellifer and C. (Selfia) spp. This is the first report of VS virus isolations from field-collected Culicoides.

Aedes↗
PubMed1987

Classification of type III (severe) open fractures relative to treatment and results.

Severe type III open fractures were subtyped according to the differences in prognosis for sepsis, amputation, and treatment: IIIA (adequate soft-tissue coverage of bone with extensive soft-tissue laceration or flaps), IIIB (extensive soft-tissue loss with periosteal stripping and bone exposure), and IIIC (arterial injury requiring repair). Analysis of 303 open fractures revealed a sepsis rate of 0% in type I, 2.5% in type II, and 13.7% in type III. The rate of amputation was 18.7%, and the rate of nonunion was 18.5% in type III open fractures. Type IIIA, IIIB, and IIIC open fractures had sepsis rates of 5%, 28%, and 8%, and amputation rates of 2.5%, 5.6%, and 25%, respectively. The overall wound sepsis rate in the 303 open fractures was 4.4%, and the nonunion rate was 8.6%.

Amputation, Surgical↗
PubMed1986

Methylation of chromatin in vitro.

The endogenous DNA methylase in nuclei isolated from growing mouse cells preferentially methylates DNA in micrococcal nuclease-resistant regions probably as a result of the location in these regions of the preponderance of hemimethylated sites. Added mouse ascites cell DNA methylase catalyses the methylation of exposed, nuclease-sensitive DNA in chromatin from growing or non-growing mouse or insect cells. The poor acceptor ability of nuclease-resistant regions in this situation is due to the presence of histone proteins which block de novo methylation. Transcriptionally active regions of chromatin are selectively methylated in vitro by either endogenous or added DNA methylase.

Animals↗
PubMed1986

Acute complications of endotracheal intubation. Relationship to reintubation, route, urgency, and duration.

Sixty-one consecutive medical intensive care unit patients who were intubated for more than three days were prospectively studied for complications. Patients who were reintubated had a higher incidence of all complications (chi square = 5.4; p less than .025), as did those with prolonged intubation (chi square = 16.1; p less than .005). Neither route nor urgency had an adverse clinical effect. In contrast there was a 13 percent incidence of acute tracheolaryngeal complications, but no association was found with reintubation, route, urgency, or total duration of endotracheal intubation.

Adult↗
PubMed1985

Delayed methylation and the matrix bound DNA methylase.

It is shown that the methylation of DNA that occurs in isolated nuclei is "delayed methylation". This methylation is not reduced in nuclei which have been pretreated with 0.2M NaCl to extract the soluble methylase suggesting that this methylation is the product of a firmly bound matrix associated DNA methylase. Evidence is provided that, like the methylase, the DNA substrate is associated with the nuclear matrix.

Animals↗
PubMed1985

Phase I evaluation of a synthetic mutant of beta-interferon.

A synthetic mutant of beta-interferon, produced by recombinant DNA technology, was prepared with serine substituted for the naturally occurring cysteine at amino acid 17. This molecule, after purification to homogeneity, was evaluated in 23 patients with cancer for tolerated doses, safety, and pharmacokinetics. Each patient was begun on twice weekly administration, one dose i.m., then an identical dose i.v. Doses, escalated weekly, were tolerated by 9 of 12 patients at 100 X 10(6) units i.m., 11 of 14 patients at 100 X 10(6) units i.v., and 8 of 10 patients receiving i.v. doses of 200 X 10(6) units. Fever (greater than or equal to 38.9 degrees C), the commonest cause for ceasing dose escalation, occurred in 11 of 13 patients who developed limiting i.v. toxicity and 6 of 11 who developed limiting i.m. toxicity. Patients who did not have progressive cancer after completion of dose escalation received five consecutive daily doses at their maximum tolerated single dose by each route, i.m. and i.v. These two 5-day treatments were given without difficulty. All patients treated with 300 X 10(6) units or less, i.m. (n = 13) or i.v. (n = 10), were able to receive five daily doses without limiting toxicity. Peak serum titers occurred immediately after i.v. administration and declined in an exponential manner thereafter. Despite absence of measurable titers in serum after i.m. injection, fever and significant (P less than 0.05) depression of WBC and platelet counts, serum calcium, and serum cholesterol occurred (prestudy to maximum tolerated dose). An immunoglobulin antibody to beta-interferon, detected by enzyme-linked immunoabsorbent assay, developed in 17 of 23 patients. Neutralizing activity (titer 10(2] was found in only 1 of 23 patients. No immune-mediated sequelae (symptomatic or renal) were identified. Further Phase I and II trials with this molecule will determine whether it will prove to have a better therapeutic index or different spectrum of therapeutic activity from alpha-interferon or gamma-interferon.

Adult↗
PubMed1979

The effect of "warm-up" on exercise-induced asthma.

To determine the effect of "warm-up" on exercise-induced asthma (EIA) 18 subjects ( mean age 19.7 years) performed five minutes of submaximal treadmill running to achieve a heart rate (HR) of 85% of predicted maximum for age. One such exercise test was preceded by "warm-up" and one was not. "Warm-up" consisted of three minutes of treadmill walking or jogging to attain 60% of predicted maximun HR for age. An identical incidence (77.8%) and severity (38.1% mean decrease in FEV1) of EIA was recorded after treadmill running whether preceded by "warm-up" or not. While this study does not support the concept that "warm-up" could reduce the likelihood of EIA, it is recommended that a longer, more intense "warm-up" involving interval exercise should be evaluated before rejecting the view that "warm-up" ameliorates EIA.

Adolescent↗