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Biomedical subjects

J S Russell

Publications and source records attributed to J S Russell.

14 recordsLinked to original sources
PubMed2005

Aesthetic orthodontic brackets.

Due to an increasing demand for superior aesthetics during fixed appliance treatment, the use of aesthetic brackets has grown in popularity over recent years. Although often requested by patients, aesthetic brackets are not without their disadvantages. This article presents the currently available plastic and ceramic brackets and discusses the potential problems associated with each. Recent advances, introduced by manufacturers in an attempt to overcome their clinical disadvantages, are described.

Ceramics↗
PubMed2000

Cotton boll abscission and yield losses associated with first-instar bollworm (Lepidoptera: Noctuidae) injury to nontransgenic and transgenic Bt cotton.

Field tests were conducted in northeastern Louisiana to determine the effects of infestations by Helicoverpa zea (Boddie) on cotton bolls of varying ages. First instars were caged on bolls of nontransgenic ('Deltapine 5415') or transgenic Bacillus thuringiensis Berliner variety kurstaki (Bt) ('NuCOTN 33B') cotton from 29 June to 11 August during 1997 and 1998. Deltapine 5415 bolls that accumulated 179 (7.2 d), 281 (11.2 d), and 253 (10.1 d) heat units beyond anthesis were safe from bollworm-induced abscission at 72 h after infestation, 7 d after infestation, and at the time of harvest, respectively. NuCOTN 33B bolls that accumulated 157 (6.3 d), 185 (7.4 d), and 180 (7.2 d) heat units beyond anthesis were safe from bollworm-induced abscission at 72 h after infestation, 7 d after infestation, and at the time of harvest, respectively. Bollworm larvae reduced seedcotton weights of Deltapine 5415 bolls that accumulated between 58.5 (2.3 d) and 350.5 (14.0 d) heat units beyond anthesis. Seedcotton weights of NuCOTN 33B bolls that accumulated between 0 and 281 (11.2 d) heat units beyond anthesis were reduced by bollworm injury. Deltapine 5415 and NuCOTN 33B bolls that accumulated 426.5 (17.1 d) and 299.5 (12.0 d) heat units beyond anthesis, respectively, before infestation were not injured by first-instar bollworm larvae. These data provide information about late-season insecticide termination strategies for bollworms on nontransgenic and transgenic Bt-cotton. This, in turn, will help pest managers determine when insecticides are no longer economical during the late season.

Animals↗
PubMed1999

Radiosensitization of human tumor cell lines induced by the adenovirus-mediated expression of an anti-Ras single-chain antibody fragment.

The expression of activated ras genes has been implicated as a contributing factor to the radioresistance of tumor cells. As a strategy for compromising Ras protein activity and potentially enhancing the radiosensitivity of tumor cells, we have investigated the application of the AV1Y28 adenovirus, which expresses a single-chain antibody fragment directed against p21 Ras proteins. The ability of AV1Y28 transduction to modulate radioresponse was investigated using four human tumor cell lines--U251 glioblastoma, MIA PaCa-2 pancreatic carcinoma, and the colon carcinomas SW620 and HT29. Cultures were exposed to sufficient levels of AV1Y28 to transduce more than 90% of the cells; 24 h later, cultures were exposed to ionizing radiation, and clonogenic cell survival was determined. Tumor cell survival was reduced by 40-50% when the tumor cell lines were exposed to AV1Y28 only. In addition, for each tumor cell line, AV1Y28 exposure enhanced the level of radiation-induced cell killing. Dose enhancement factors at a surviving fraction of 0.1 ranged from 1.3 to 1.5. Furthermore, for each of the cell lines, the surviving fraction at 2 Gy was significantly reduced by AV1Y28 exposure. In contrast to the results seen in tumor cells, the radiosensitivity of a normal human fibroblast cell line was not affected by AV1Y28. These data indicate that this anti-Ras adenovirus enhances the radiosensitivity of tumor cells but does not affect the radiosensitivity of normal cells.

Adenoviridae↗
PubMed1996

Substance P and neurokinin A metabolism by cultured human skeletal muscle myocytes and fibroblasts.

A recent study determined that cultured human skeletal muscle adult myoblasts, myotubes, and fibroblasts degraded angiotensins and kinins via neutral endopeptidase-24.11 (NEP-24.11: EC 3.4.24.11) and aminopeptidase N (APN: EC 3.4.11.2). Due to the possible importance of other peptides to skeletal muscle blood flow and function, the present study looked specifically at the metabolism of the neurokinins substance P (SP) and neurokinin A (NKA) by skeletal muscle peptidases. The results show that SP is degraded not only by NEP-24.11, but also sequentially by dipeptidyl(amino)peptidase IV (DAP IV: EC 3.4.14.5)/APN. NKA is unaffected by DAP IV but is metabolized by NEP-24.11 and APN. NEP-24.11 was inhibited by phosphoramidon (IC50 = 80 nM), thiorphan and ZINCOV, DAP IV by diprotin A (IC50 = 8 microM), and APN by amastatin (IC50 = 50 nM) and bestatin (IC50 = 100 microM). Skeletal muscle myocyte and fibroblast metabolism of SP and NKA may regulate local skeletal muscle vascular and extravascular functions including SP- and NKA-mediated nerve-induced vasodilation. Inhibition of both NEP-24.11 and DAP IV/APN may increase skeletal muscle blood flow and decrease peripheral vascular resistance via potentiation of local neurokinin levels.

Adult↗
PubMed1995

Angiotensin and bradykinin metabolism by peptidases identified in skeletal muscle.

We have identified angiotensin-converting enzyme, neutral endopeptidase-24.11, and aminopeptidase M in a purified glycoprotein fraction of rabbit skeletal muscle membranes. The identification was based on substrate specificity and sensitivity to selective inhibitors. Angiotensin I metabolism was due to angiotensin-converting enzyme-mediated conversion to angiotensin II and neutral endopeptidase-24.11-mediated conversion to angiotensin(1-7). Bradykinin was degraded by angiotensin-converting enzyme and neutral endopeptidase-24.11; angiotensin II by neutral endopeptidase-24.11; and angiotensin III by neutral endopeptidase-24.11 and aminopeptidase M. Thus, the effects of angiotensins and kinins on skeletal muscle blood flow and metabolism may be regulated by local angiotensin-converting enzyme, neutral endopeptidase-24.11, and aminopeptidase M.

Aminopeptidases↗
PubMed1995

Angiotensin and bradykinin metabolism by peptidases identified in cultured human skeletal muscle myocytes and fibroblasts.

Angiotensin (ANG) and kinin metabolizing enzymes, angiotensin-converting enzyme (ACE; EC 3.4.15.1), neutral endopeptidase-24.11 (NEP-24.11; EC 3.4.24.11), and aminopeptidase M (AmM; EC 3.4.11.2), have recently been identified in a purified skeletal muscle glycoprotein fraction. We have analyzed the cellular localization of these enzymes. In cultured human skeletal muscle adult myoblasts, myotubes, and fibroblasts, kinins and angiotensins were metabolized by NEP-24.11 and AmM but not by ACE. NEP-24.11 degraded ANG II, ANG III. and bradykinin (BK) and converted ANG I to the active metabolite ANG(1-7). ANG III was converted to the novel ANG IV metabolite [des-Arg1]ANG III by AmM. These data suggest that, due to their abundance in the body, skeletal muscle myocytes and fibroblasts may play a major role in modulation of the systemic and local effects of angiotensins and kinins. This role could be particularly important in individuals receiving treatment with ACE inhibitors.

Aminopeptidases↗
PubMed1994

Serving severely mentally ill people in a major Canadian city.

Over the past twenty years, GVMHS has been the single organization taking ultimate responsibility for the seriously mentally ill throughout the city. It uses central coordination coupled with community-based teams and partnership programs with other agencies to strike a useful balance between integration and flexibility. GVMHS's mission throughout that time has been to provide everyday community support, networking, case management, rehabilitation, and counseling services to as many seriously mentally ill persons with concomitant disabilities as possible. To carry out that mission, GVMHS has developed some innovative solutions for the problems of community support--problems such as psychiatric emergencies, crises, community demands for service outside the mandate, and workload management. GVMHS has also developed dual-diagnosis, multicultural, multiagency case coordination for the multiproblem client (Buckley and Bigelow, 1992), specialized family and child programs, and specialized geriatric programs. This has all been possible only because financial support is available on an ongoing basis at a level adequate to provide good, dependable services. GVMHS has been proven an effective service in a number of studies (Bigelow and Beiser, 1978; Beiser, Shore, Peters, and Tatum, 1985). It has also demonstrated good cost-efficiency (Bigelow and McFarland, 1989) and abundant innovation and adaptation to emerging challenges (Bigelow, McFarland, Russell, and Sladen-Dew, 1990). It has proven that dedicated, well-trained professionals working at the community level will work hard and smart and that an agency and its staff will stick to the mandate of serving people with serious mental illnesses and disabilities even under pressure to do otherwise. The intriguing thing is that this productivity is not driven by competition, incentives, or threat: none of these factors presses upon the Greater Vancouver Mental Health Services Society from without and none is built in. The excellent performance of GVMHS seems to derive from the professional dedication and motivation of the clinical staff and its administration.

Canada↗
PubMed1993

Managing acute care.

In the last few years, much medical-facility construction has been driven by what insurers want. Hospitals have built facilities for well-reimbursed procedures and closed money-losing ones. Health-maintenance organizations increasingly expect to hold down costs by making prepayment arrangements with doctors and their hospitals. President Clinton has pledged early action on health-care reform, which will likely change planners' priorities. Whether the nation goes to Clintonian "managed competition" or a Canadian-style nationwide single-payer system (the two most likely options), the projects on these pages reflect two large-scale trends that are likely to continue: the movement of more procedures from inpatient to outpatient facilities and the separation of treatment functions from ordinary office and administrative tasks so that the latter are not performed in the same high-cost buildings as technology-intensive procedures. Various schemes that make care more "patient-centered" have been tried and been shown to speed healing, even for outpatients, but such hard-to-quantify issues get short shrift in an era of knee-jerk cost containment. The challenge in tomorrow's healthcare universe--whatever it becomes--will be to keep these issues on the table.

Architecture↗
PubMed1993

Two owners face new facts of life.

Two diverse non-profit clients see big changes in the world in which they operate. Can the Philadelphia Zoo maintain its status as one of America's best zoos in the face of leadership changes and a prolonged economic slump within its community? And how will Kaiser Permanente, a health-care giant, meet the challenges of universal "managed" care?

Animals↗