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Biomedical subjects

A Davis

Publications and source records attributed to A Davis.

At least 109 records · Page 6Linked to original sources

Defining the implant treatment volume for patients with low risk prostate cancer: does the anterior base need to be treated?

PURPOSE: An increased incidence of acute urinary retention has been reported after interstitial prostate radiation therapy when the anterior base of the prostate gland receives 100% of the prescription dose. The frequency of prostate cancer in this location as a function of the pre-treatment prostate specific antigen (PSA), biopsy Gleason score, and 1992 American Joint Commission on Cancer Staging (AJCC) was determined. METHODS AND MATERIALS: One hundred four men treated at the Brigham and Women's Hospital with radical prostatectomy for clinically localized prostate cancer between 1995-1996 comprised the study population. Prostatectomy specimens were whole mounted and the location of each tumor foci enumerated. RESULTS: Of 269 foci of prostate cancer found in 39 low-risk prostate cancer patients (PSA < 10 ng/ml, biopsy Gleason score < or = 6, and 1992 AJCC clinical stage T1c,2a), a single focus (0.37%) was noted in the anterior base. Conversely, 20/355 (5.6%) and 18/251 (7.2%) tumor foci were noted in the anterior base in 43 patients with intermediate risk and 24 patients with high-risk disease, respectively. CONCLUSIONS: A new definition of the treatment volume excluding the anterior base for low-risk prostate cancer patients may be justified.

Brachytherapy↗

Diversity of Microorganisms Isolated from Amber.

> Abstract Claims that organisms can be cultured from amber, if substantiated, would be significant contributions to our understanding of the evolution, tenacity, and potential spread of life. Three reports on the isolation of organisms from amber have been published. Cano and Borucki recently reported the isolation of Bacillus sphaericus and Lambert et al. have described a new species designated Staphylococcus succinus from 25-40 million year old Dominican amber. These characterized organisms were phylogenetically distant from extant relatives and the Staphylococcus sp. sufficiently far removed from other extant staphylococci to be considered a new species. Here we report the culture of bacteria from Dominican and previously untested 120 million year old Israeli (Lebanese lode) amber. Twenty-seven isolates from the amber matrix have been characterized by fatty-acid profiles (FAME) and/or 16S rRNA sequencing. We also performed a terminal restriction fragment pattern (TRF) analysis of the original amber before prolonged culture by consensus primer amplification of the 16S rRNA followed by restriction enzyme digestion of the amplicons. Sample TRFs were consistent with a sparse bacterial assemblage and included at least five of the isolated organisms. Finally, we microscopically mapped the internal topography of an amber slice.http://link.springer-ny.com/link/service/journals/00248/bibs/38n1p58.html

Journal Article↗

Clinician/patient interaction: communicating the benefits and risks of oral contraceptives.

Myths and misperceptions continue to influence women's opinions about oral contraceptives (OC), despite the immense body of evidence regarding OC safety and efficacy. Patient opinions about OC failure rates and health risks are often far from proven fact, and the health benefits of OC are too often unrecognized. Because successful OC use requires an informed patient, effective communication between clinicians and their patients is needed to correct misinformation, relieve unnecessary fears, and increase OC use. A variety of interactive counseling skills and attitudes can improve the process of patient counseling; they are especially crucial for adolescents, who may be reluctant or unable to easily articulate their concerns. Counseling messages can be geared specifically to the interests and concerns of particular age groups: adolescents, young adults, and perimenopausal women. With thoughtful planning and involvement of all members of the healthcare team, clinicians can create time and opportunities for the provision of consistent, appropriate counseling to all candidates for OC use.

Adolescent↗

The mitochondrial DNA C3303T mutation can cause cardiomyopathy and/or skeletal myopathy.

OBJECTIVE: Several mutations in mitochondrial DNA have been associated with infantile cardiomyopathy, including a C3303T mutation in the mitochondrial transfer RNA(Leu(UUR)) gene. Although this mutation satisfied generally accepted criteria for pathogenicity, its causative role remained to be confirmed in more families. Our objective was to establish the frequency of the C3303T mutation and to define its clinical presentation. STUDY DESIGN: Families with cardiomyopathy and maternal inheritance were studied by polymerase chain reaction/restriction fragment length polymorphism analysis looking for the C3303T mutation. RESULTS: We found the C3303T mutation in 8 patients from 4 unrelated families. In one, the clinical presentation was infantile cardiomyopathy; in the second family, proximal limb and neck weakness dominated the clinical picture for the first 10 years of life, when cardiac dysfunction became apparent; in the third family, 2 individuals presented with isolated skeletal myopathy and 2 others with skeletal myopathy and cardiomyopathy; in the fourth family, one patient had fatal infantile cardiomyopathy and the other had a combination of skeletal myopathy and cardiomyopathy. CONCLUSIONS: Our findings confirm the pathogenicity of the C3303T mutation and suggest that this mutation may not be rare. The C3303T mutation should be considered in the differential diagnosis of skeletal myopathies and cardiomyopathy, especially when onset is in infancy.

Adolescent↗

Subcellular immunolocalization of protein kinase CK2 in normal and carcinoma cells.

CK2 is a messenger-independent protein serine/threonine kinase that has been implicated in cell growth and proliferation. Our recent analysis of squamous cell carcinomas of the head and neck (SCCHN) revealed a significant elevation in CK2 activity in these tumor cells relative to normal mucosa of the upper aerodigestive tract and suggested a correlation with aggressive tumor behavior and poor clinical outcome. In order to further define the distribution of CK2 in these tissues, we have examined the immunohistochemical staining pattern of surgical specimens of both SCCHN tumors and normal upper aerodigestive tract mucosa using a monoclonal antibody directed against the catalytic subunit CK2-alpha of the kinase, and have compared these data with the subcellular distribution of CK2 activity in these same tissues. These measurements showed that CK2 is predominantly localized to the nuclei of the tumor cells, which agreed closely with the immunohistochemical staining pattern of CK2-alpha in tumor cells. The chiefly nuclear distribution of CK2-alpha immunostaining found consistently in SCCHN tumor cells and tumor-infiltrating lymphocytes contrasted with a relatively more predominant cytosolic staining pattern exhibited by various cellular constituents of normal oropharyngeal mucosa. The immunostaining pattern of CK2-alpha revealed that staining was observed in the cells stained for the proliferation-marker Ki-67; however, strong distinct immunostaining for CK2-alpha was also observed in large numbers of other cells in these same tumors, suggesting that CK2 elevation in these tumors is not a reflection of proliferative activity alone, but may also relate to the pathobiological behavior of the tumor.

Carcinoma, Squamous Cell↗

Novel suicide ligands of tubulin arrest cancer cells in S-phase.

It is presently accepted that the mechanism of action for all anti-tumor tubulin ligands involves the perturbation of microtubule dynamics during the G2/M phase of cell division and subsequent entry into apoptosis [1]. In this report, we challenge the established dogma by describing a unique mechanism of action caused by a novel series of tubulin ligands, halogenated derivatives of acetamido benzoyl ethyl ester. We have developed a suicide ligand for tubulin, which covalently attaches to the target and shows potent cancericidal activity in tissue culture assays and in animal tumor models. These compounds target early S-phase at the G1/S transition rather than the G2/M phase and mitotic arrest. Bcl-2 phosphorylation, a marker of mitotic microtubule inhibition by other tubulin ligands was dramatically altered, phosphorylation was rapid and biphasic rather than a slow linear event. The halogenated ethyl ester series of derivatives thus constitute a unique set of tubulin ligands which induce a novel mechanism of apoptosis.

Antineoplastic Agents↗

A prospective case-controlled study of 197 men, 50-60 years old, selected at random from a population at risk from hyperlipidaemia to examine the relationship between hyperlipidaemia and sensorineural hearing loss.

Hyperlipidaemia has been reported as an aetiological factor in sensorineural hearing loss. Reports on this subject have been retrospective, lacked adequate controls, or have been based on a series of cases which may represent incidental findings as hyperlipidaemia is prevalent in the normal population. The published evidence that hyperlipidaemia causes hearing problems is contradictory and warrants further controlled trials: A prospective case-controlled study was conducted of 197 men between 50 and 60 years old selected at random from a population at risk from ischaemic heart disease or hyperlipidaemia. Hearing thresholds, relevant variables and--on two occasions--their fasting cholesterol levels, were recorded. The control subjects were recruited from patients undergoing nasal surgery for either internal or external structural abnormalities. All study and control groups were also compared with the National Study of Hearing (NSH) data. When hearing thresholds were grouped together as 0.5, 1, 2 and 4 kHz, 0.5, 1, 2 kHz or 4, 6 and 8 kHz there were no statistically significant differences except at 4, 6 and 8 kHz in the worse hearing ear where the at risk group had better hearing thresholds, P = 0.0475. However, the differences which existed became reduced across all frequencies when the subgroup with fasting lipids > 6.5 mmol/l was compared with the at risk group as a whole against the NSH data.

Audiometry, Pure-Tone↗

A prospective case-controlled study of patients presenting with idiopathic sensorineural hearing loss to examine the relationship between hyperlipidaemia and sensorineural hearing loss.

The prevalence of hyperlipidaemia in the normal population means that hyperlipidaemia is often found in patients who have a hearing loss of unknown aetiology. We prospectively undertook a case-controlled study of 85 patients presenting consecutively with a sensorineural hearing loss of unknown aetiology to see if the prevalence of hyperlipidaemia differed between the group with an idiopathic sensorineural hearing loss and a control population. Control subjects were recruited from patients undergoing nasal surgery for structural abnormalities. Both the study and control groups were also compared with the National Study of Hearing data. Hyperlipidaemia was no more prevalent in a population with idiopathic sensorineural hearing loss than a control population. No consistent association between hyperlipidaemia and hearing loss was found.

Adult↗

Antioxidant enzymes, inflammatory indices and lifestyle factors in older men: a cohort analysis.

We examined the relationship between blood antioxidant enzyme activities, indices of inflammatory status and a number of lifestyle factors in the Caerphilly prospective cohort study of ischaemic heart disease. The study began in 1979 and is based on a representative male population sample. Initially 2512 men were seen in phase I, and followed-up every 5 years in phases II and III; they have recently been seen in phase IV. Data on social class, smoking habit, alcohol consumption were obtained by questionnaire, and body mass index was measured. Antioxidant enzyme activities and indices of inflammatory status were estimated by standard techniques. Significant associations were observed for: age with alpha-1-antichymotrypsin (p < 0.0001) and with caeruloplasmin, both protein and oxidase (p < 0.0001); smoking habit with alpha-1-antichymotrypsin (p < 0.0001), with caeruloplasmin, both protein and oxidase (p < 0.0001) and with glutathione peroxidose (GPX) (p < 0.0001); social class with alpha-1-antichymotrypsin (p < 0.0001), with caeruloplasmin both protein (p < 0.001) and oxidase (p < 0.01) and with GPX (p < 0.0001); body mass index with alpha-1-antichymotrypsin (p < 0.0001) and with caeruloplasmin protein (p < 0.001). There was no significant association between alcohol consumption and any of the blood enzymes measured. Factor analysis produced a three-factor model (explaining 65.9% of the variation in the data set) which appeared to indicate close inter-relationships among antioxidants.

Acute-Phase Proteins↗

The history of ASPRSN: a look back.

This article takes a look back at the 25-year history of the American Society of Plastic and Reconstructive Surgical Nurses (ASPRSN). Alice Davis, a founding member of the Society, examines ASPRSN's history from the beginning in 1975 through the present day in 1999.

History, 20th Century↗

New compensation model improves physician productivity.

In the mid-1990s, Meridia Health System, a hospital system in the Cleveland, Ohio, area began acquiring primary care physician practices to form the core of an integrated delivery system to compete with other providers in the area. Unfortunately, the structure of the physician compensation plan for Meridia's new physician employees caused productivity to decline and losses to mount. Meridia appointed a task force that included physicians to develop a new compensation plan that bases pay on the application of a collection rate percentage to each physician's gross fee-for-service billings. While not perfect, the new compensation plan is helping both Meridia and its physicians achieve their mutual goals of high-quality care, reasonable productivity, and operating efficiency.

Community Networks↗

Interferon-beta gene therapy inhibits tumor formation and causes regression of established tumors in immune-deficient mice.

Despite the potential of type 1 interferons (IFNs) for the treatment of cancer, clinical experience with IFN protein therapy of solid tumors has been disappointing. IFN-beta has potent antiproliferative activity against most human tumor cells in vitro in addition to its known immunomodulatory activities. The antiproliferative effect, however, relies on IFN-beta concentrations that cannot be achieved by parenteral protein administration because of rapid protein clearance and systemic toxicities. We demonstrate here that ex vivo IFN-beta gene transduction by a replication-defective adenovirus in as few as 1% of implanted cells blocked tumor formation. Direct in vivo IFN-beta gene delivery into established tumors generated high local concentrations of IFN-beta, inhibited tumor growth, and in many cases caused complete tumor regression. Because the mice were immune-deficient, it is likely that the anti-tumor effect was primarily through direct inhibition of tumor cell proliferation and survival. Based on these studies, we argue that local IFN-beta gene therapy with replication-defective adenoviral vectors might be an effective treatment for some solid tumors.

Adenoviridae↗

Effects of drying methods and additives on structure and function of actin: mechanisms of dehydration-induced damage and its inhibition.

Limited stability impedes the development of industrial and pharmaceutical proteins. Dried formulations are theoretically more stable, but the drying process itself causes structural damage leading to loss of activity after rehydration. Lyophilization is the most common method used to dry proteins, but involves freezing and dehydration, which are both damaging to protein. We compared an air-drying method to freeze-drying to test the hypothesis that terminal dehydration is the critical stress leading to loss of activity. The secondary structure of air-dried and freeze-dried actin was analyzed by infrared spectroscopy and related to the level of activity recovered from the rehydrated samples. Actin dried by either method in the absence of stabilizers was highly unfolded and the capacity to polymerize was lost upon rehydration. The degree of unfolding was reduced by air-drying or freeze-drying actin with sucrose, and the level of activity recovered upon rehydration increased. The addition of dextran to sucrose improved the recovery of activity from freeze-dried, but not air-dried samples. Dextran alone failed to protect the structure and function of actin dried by either method, indicating that proteins are not protected from dehydration-induced damage by formation of a glassy matrix. In some cases, recovered activity did not correlate directly with the level of structural protection conferred by a particular additive. This result suggests that secondary structural protection during drying is a necessary but not sufficient condition for the recovery of activity from a dried protein after rehydration.

Actins↗

Genomic organization and partial duplication of the human alpha7 neuronal nicotinic acetylcholine receptor gene (CHRNA7).

The human alpha7 neuronal nicotinic acetylcholine receptor gene (HGMW-approved symbol CHRNA7) has been characterized from genomic clones. The gene is similar in structure to the chick alpha7 gene with 10 exons and conserved splice junction positions. The size of the human gene is estimated to be larger than 75 kb. A putative promoter 5' of the translation start in exon 1 has been cloned and sequenced. The promoter region lacks a TATA box and has a high GC content (77%). Consensus Sp1, AP-2, Egr-1, and CREB transcription factor binding sites appear to be conserved between bovine and human genes. The alpha7 nAChR gene was found to be partially duplicated, with both loci mapping to the chromosome 15q13 region. A yeast artificial chromosome contig was constructed over a genetic distance of 5 cM that includes both alpha7 loci and the region between them. Four novel exons are described, located in genomic clones containing the partially duplicated gene. The duplicated sequences, including the novel exons, are expressed in human brain.

Base Sequence↗