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L Davis

Publications and source records attributed to L Davis.

At least 37 records · Page 2Linked to original sources
PubMed1995

Comparative analysis of mouse NotI linking clones with mouse and human genomic sequences and transcripts.

NotI cleavage sites are frequently associated with CpG islands that identify the 5' regulatory sites of functional genes in the genome. Therefore we analyzed a sample of 22 NotI linking clones prepared from mouse brain DNA, to determine whether these mouse NotI site associated clones could be used for comparative analysis of mouse and human genomes by cross-reaction with both mouse and human genomic DNA and RNA in Southern and Northern hybridization. We further examined whether we could establish the identity of these clones with known genes by comparing the nucleotide sequences surrounding the NotI site with the GenBank database. We observed that 70% of the clones cross-hybridized with human DNA and that 4 of 11 tested clones (36%) detected a transcript in human HeLa cells RNA whereas 73% clones (8/11) detected transcripts in mouse RNAs from one or more organs. Single pass sequence analysis was successful on 16 of 19 clones. The GC content in these sequence was very high (48.8% to 73.8%) suggesting that 12 of 16 sequenced clones contained a CpG island. Three out of 19 clones showed significant similarity with previously analyzed mouse gene sequences in GenBank, including the mouse rRNA gene family, cathepsin and the scip POU-domain genes. In addition, two sequences showed significant similarity to the human and rabbit protein phosphatase 2A-beta subunit and the human transforming growth factor-beta. Thus, 5 of 16 clones showed homology with identified genes. These results and the recent work of using RLGS methods for genetic mapping indicate that NotI linking clones can be used to efficiently cross reference a comparative analysis of the mouse and human genomic maps.

Animals↗
PubMed1995

Race, control, mastery, and caregiver distress.

This study investigated the relationship between race, psychological resources of sense of control and caregiver mastery, and distress outcomes of caregiver depression and role stain among 77 African American and 138 White spouse caregivers of persons with dementia. Patterns of association between psychological resources and caregiving distress outcomes varied by type of outcome. Sense of control had a direct negative relationship with depression. Caregiver mastery moderated the effects of stressors on depression and was the only significant psychological resource predicting role strain. Although African American caregivers were less likely to report caregiver depression and role strain, there were no race differences in the process influencing caregiver distress.

Aged↗
PubMed1995

Using a group-oriented contingency to increase social interactions between children with autism and their peers. A preliminary analysis of corollary supportive behaviors.

The effects of a group-oriented contingency on the social and supportive interactions of three preschoolers with autism and their socially competent peers were examined. Children participated in daily manipulative play activities in groups of three (including one target child and two peers). A group reinforcement contingency increased all three target children's social interactions with peers (e.g., share, assistance, and play organizers) but produced few or no corollary supportive exchanges within the playgroups (e.g., one socially competent youngster tells another to "Ask [target child] to share the Lego toys with us"). After a withdrawal of treatment phase in which social interactions decreased to low levels, children were taught to direct supportive comments to other members of their playgroups. Following this brief training, the interdependent group contingency was reinstated to reinforce the share, assistance, and play organizer exchanges between the target children and peers. In addition to interacting with the target children, socially competent youngsters also used supportive prompts to facilitate the social exchanges between their remaining group members. Children's social and supportive interactions decreased and increased again during subsequent baseline and group contingency phases. These results are discussed with regard to the efficacy of group-oriented contingencies and the function of supportive peer behaviors.

Autistic Disorder↗
PubMed1995

Primary sclerosing cholangitis in 32 children: clinical, laboratory, and radiographic features, with survival analysis.

The clinical presentation and outcome of 32 children with primary sclerosing cholangitis (PSC) are reviewed, the largest North American series. The majority of patients were diagnosed in their second decade (median age: 13 years). Four children presented before the age of 2 years, but none in the neonatal period. Seventeen patients had inflammatory bowel disease (IBD), all with colitis, 14 ulcerative colitis, and 3 Crohn's disease. Eight patients presented with chronic liver disease before clinical onset of IBD. Only 8 of 32 patients were jaundiced at presentation. Fifteen of 32 had a normal serum alkaline phosphatase (ALP) level at presentation. Nine children presented with features similar to those of autoimmune hepatitis. Cholangiography was performed in all cases and classified by a scoring system specifically developed for pediatric patients. Intrahepatic disease predominated; in only three cases a common bile duct stricture was identified requiring stenting. Findings on the initial liver biopsy were classified according to Ludwig's criteria for staging PSC: there were 15 biopsies in stages 1 to 2 and 17 biopsies stages 3 to 4. HLA class I and II antigens were determined in 27 patients. An increased incidence of HLA B8 and DR2(15) but not DRw52a (DRB3*0101) was found. Anti-neutrophil cytoplasmic antibody (ANCA) was positive in 10 of 24 patients tested. Survival analysis indicated that a later age at presentation, splenomegaly, and prolonged prothrombin time (PT) at presentation were significant contributors to the prediction of poor outcome (i.e., death or listing for transplantation). Liver transplantation was successfully performed in seven children. Physicians must maintain a high index of suspicion of PSC in any child or young adult presenting with chronic liver disease, especially in the presence of IBD, even with a normal serum alkaline phosphatase level.

Adolescent↗
PubMed1995

Evaluation of neuromuscular effects and antagonism of rocuronium bromide: a preliminary report.

Twenty ASA I-II patients received either 2 or 3 x ED95 doses of rocuronium bromide during nitrous oxide, oxygen, propofol, fentanyl-based anaesthesia. The mean times to maximum block were 98 s and 74 s and the mean duration of clinical relaxation (recovery to 25% T1) was 35 min and 46 min following 620 micrograms kg-1 and 930 micrograms kg-1, respectively. Neuromuscular blockade was antagonized with either neostigmine or edrophonium from a twitch height of 25%. Although there was no significant difference between the recovery times neostigmine appeared to give more consistent antagonism of rocuronium-induced blockade.

Adolescent↗
PubMed1994

2-Amino-3-ketobutyrate-CoA ligase from beef liver mitochondria. Purification and partial sequence.

2-Amino-3-ketobutyrate-CoA ligase (EC 2.3.1.29), or aminoacetone synthetase, has been purified by a nine-step procedure from 1.0 kg of beef liver to yield 8.8 mg of homogeneous enzyme. The homogeneous form of the enzyme, a monomer of M(r) = 44,000, shows unusually high absorption at 430 nm, with a ratio of absorbance at 280 and 430 nm of 2.6. On storage a species with an additional absorption peak at 332 is formed. Neither the 430-nm peak nor the 332-430 ratio is affected by pH or substrates. The peak at 430 nm and enzyme activity are both reduced by borohydride reduction and treatment with cysteine. The first 21 amino acids at the NH2-terminal of the ligase occur in the sequence Ser-Ala-Leu-Ala-Gln-Leu-Arg-Gly-Ile-Leu-Glu-Glu-Glu-Leu-Glu-Ser-Ile-Arg- Gly-Ala - Gly. No homology is detectable in the first 20 amino acids of the Escherichia coli and beef liver mitochondria enzymes. However, homology is found around the lysine residue to which the pyridoxal 5'-phosphate is attached in the two enzymes. A very hydrophobic peptide containing pyridoxal phosphate having the following sequence Leu-Leu-Gly-Val-Met-Asp-Gln-Val-Thr-Ile-Ile-Asn-Ser-Thr-Leu-Gly-Lys(P xy)-Ala- Leu-Gly-Gly-Ala-Ser-Gly-Gly-Tyr-Thr-Thr-Gly-Pro-Gly-Ala-Leu-Val has been isolated from the ligase. Fourteen residues around the lysine to which the pyridoxal 5'-phosphate is bound are completely identical with the pyridoxal 5'-phosphate containing peptide isolated from the E. coli 2-amino-3-ketobutyrate-CoA ligase.

Acetyltransferases↗
PubMed1994

Preparative in situ hybridization: selection of chromosome region-specific libraries on mitotic chromosomes.

We have developed preparative in situ hybridization (Prep-ISH) of complex DNA populations to mitotic chromosomes as a means of generating chromosome region-specific DNA subpopulations. Prep-ISH is a combination of two cytogenetic techniques: in situ hybridization of DNA molecules to mitotic chromosomes and chromosome microdissection. Here, we present test cases demonstrating the feasibility of this approach on mouse and human genomes, using single nuclei, single chromosomes, or single chromosomal subregions to assess sensitivity, specificity, and representation of the Prep-ISH technique. Prep-ISH has a number of applications in studies of gene expression and genome organization, including efficient cytogenetic sorting of tissue-specific cDNAs and genomic DNA libraries. In addition, Prep-ISH is likely to dramatically reduce the number of candidate genes to aid in gene discovery efforts and to improve efficiency of developing transcription maps and YAC and cosmid contigs through defined cytogenetic regions.

Animals↗
PubMed1994

Purification and structural characterization of porcine L-threonine dehydrogenase.

L-Threonine dehydrogenase was purified 10,000-fold to a specific activity approximately 300 mumol.min-1.mg-1 protein from porcine liver mitochondria. Purification to apparent homogeneity was achieved by sequential chromatography on DEAE Sepharose FF, Affi-Gel Blue, Sephacryl S-200, Matrex Gel Red A, and Matrex Gel Green A. The subunit molecular mass was estimated as 37 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, while an apparent native molecular mass of 73 kDa was shown by gel filtration chromatography, suggesting a dimeric structure. The purified enzyme was subjected to proteolytic degradation and the resulting peptides were isolated exclusively by reverse-phase high-performance liquid chromatography. Approximately 70% of the total sequence was obtained and the N-terminal amino acid sequence of the intact polypeptide chain was thus tentatively extended to residue 40.

Alcohol Oxidoreductases↗
PubMed1994

Application of the 3M microvascular anastomotic device in non-vascular tubular structures.

In this study, the 3M microvascular anastomotic system was utilized for the first time to perform an end-to-end anastomosis in a non-vascular tubular structure, which was compared to the conventional microvascular suture method. The bicornuate rat uterus was the preferred structure because of its anatomic similarity to the human fallopian tube. Thirty Sprague-Dawley rats underwent 3M and conventional end-to-end anastomoses of their bicornuate uteri. At different intervals, the animals were explored and biopsies were taken for examination under light microscopy. Overall patency rate with the 3M technique was 68 percent vs. 96 percent with the conventional technique. Complication rates were 40 percent with the 3M device and 12 percent with the conventional method. This study concludes that, if this method is to be used on non-vascular tubular structures, further modifications to the system and additional research are mandatory, in order to recommend this technique for clinical application.

Anastomosis, Surgical↗
PubMed1994

Systemic administration of new therapeutic radioisotopes, including phosphorus, strontium, samarium, and rhenium.

New advances in systemic radionuclide therapy have increased the number of treatment options available for patients with painful osseous metastases. This form of therapy has three major appeals: 1) it addresses all sites of involvement; 2) selective absorption into bone limits irradiation of normal tissues; and 3) as a result, toxicity may be reduced and the therapeutic ratio improved. The clinical experience with radioactive phosphorus, strontium, samarium, and rhenium are reviewed. To date, the best studied and the only Food and Drug Administration approved agent is strontium-89. About 60% to 90% of patients treated with strontium-89 respond with complete or partial relief of pain for a median duration of 6 months. Large, prospectively randomized clinical trials have established the efficacy of strontium-89 as a first-line therapy and as an adjuvant to external-beam radiotherapy. Particularly advantageous is its usefulness in situations in which external-beam radiotherapy options have been exhausted and normal tissue tolerance has been reached. Newer radiopharmaceuticals are still under investigation.

Bone Neoplasms↗
PubMed1994

Cisplatin: a clinical review. Part II--Nursing assessment and management of side effects of cisplatin.

Cisplatin is one of the most active cancer treatment agents available. Unfortunately, however, cisplatin causes many untoward side effects. Nurses play a major role in administering cisplatin and in preventing and managing the adverse effects associated with this drug. In order to maximize the quality of life of patients undergoing cisplatin treatment, nurses need a thorough knowledge of its uses, administration, and side effects. This article is the second of a two-part series about cisplatin. Part I provided a review of the mechanism of action, current uses, and administration guidelines. Part II discusses the most common side effects of cisplatin and the appropriate nursing assessment and management of patients undergoing treatment with this agent. In addition, future directions for the use of cisplatin and the use of alternative agents will be discussed.

Cisplatin↗
PubMed1993

Phase I/II trial of accelerated fractionation in brain metastases RTOG 85-28.

PURPOSE: Radiation Therapy Oncology Group 85-28 represents a Phase I/II trial of accelerated fractionation in patients with brain metastases. METHODS AND MATERIALS: Patients entered had controlled or absent primary with metastases other than brain which were stable or only brain metastases with the primary uncontrolled. Karnosfky status was required to be greater than 60. Patients received 1.6 Gy twice daily separated by 4-8 hr delivered 5 days a week. The entire brain was treated to 32.0 Gy and the boost dose escalated from 16.0 Gy to 22.40 Gy and subsequently 32.00 Gy and 42.40 Gy. RESULTS: We observed no undue toxicity with escalating dose of irradiation. An incremental, although not statistically significant improvement in survival was noted with escalating doses. Median survival ranged from 4.2 months to 6.4 months with escalating dose of irradiation. Median survival also increased in patients with controlled primary tumors, non-lung primaries and solitary metastasis. CONCLUSION: The incremental improvement in survival in patients with good prognostic factors appeared encouraging. The Radiation Therapy Oncology Group will test the 54.4 Gy study against 30 Gy in 2 weeks in a Phase III trial based on the results of this trial.

Adult↗