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Biomedical subjects

S K Baker

Publications and source records attributed to S K Baker.

13 recordsLinked to original sources
PubMed2006

Size fractionation of a rumen microbial population by counter-flow centrifugal elutriation.

The microorganisms in rumen contents were physically separated into five fractions on the basis of size using counter-flow centrifugal elutriation (CCE). The use of CCE allowed the microbial population to be separated in a highly repeatable manner into two protozoal and three bacterial fractions with minimal loss of material (dry weight), and with no visible damage to the microorganisms. A Coulter counter was used to determine the sizes of the organisms in each fraction. The modified CCE method is suitable for studies of the rumen microbial ecosystem that require separation of defined fractions of the population.

Animals↗
PubMed2001

Expression of MCT1 and MCT4 in a patient with mitochondrial myopathy.

Mitochondrial myopathies (MM) are characterized by alterations in oxidative phosphorylation. The resultant increase in glycolytic flux produces a variable lactic acidosis. Intracellular acidification can induce both metabolic and, in the case of skeletal muscle, contractile dysfunction. Skeletal muscle lactate transporters have recently been identified which include both monocarboxylate transporter 1 (MCT1) and 4 (MCT4). Lactate import into oxidative skeletal muscle appears to be catalyzed by MCT1, whereas its extrusion from glycolytic fibers may be mediated by MCT4. We describe the expression of these isoforms in a patient with MM as compared to controls (n = 5). MCT4 content was 86% (>3 SD) higher in the patient with MM, whereas MCT1 content was less markedly elevated (47%), as compared to controls. These findings support previous work suggesting that the major role of MCT4 is to defend intracellular pH by extruding lactate and H(+) to the interstitium. The role of MCT1 in MM is less clear.

Aged↗
PubMed2000

Minimizing litigation risk. Documentation strategies in the occupational health setting.

When advice is given by telephone, nurses are relying on employees' or clients' own assessments of situations. Nurses do not have the benefit of examination and objective findings. Therefore, every occupational health practice should have a system for keeping a record of telephone calls. Noncompliance should be documented so the nurse is reminded of the need to consider compliance when caring for the client in the future. Documentation of report tracking and follow up, consent, client education, and discharge information contributes to improved quality of care and reduced risk of litigation. Client records should never be altered (i.e., changed) so the original entry is no longer visible. The SLIDE (Single Line, Initials, Date, Explanation) rule should be used.

Documentation↗
PubMed1999

Poor women living with HIV: self-identified needs.

Women with HIV are a growing at-risk population in our communities. They are often poor members of minority groups who have responsibilities for dependent children and other family members. They may experience physiological, psychological, and social symptoms and have needs that are unique to them as women. The purpose of this study was to give women with HIV the opportunity to identify their needs. Using the Objects Content Test, 48 women attending HIV clinics in a midsouth city listed 349 needs: 32% psychosocial, 14% physical, 13% service and maintenance, and 11% financial and legal. It is important for nurses working with these women in the community to know how they perceive their own needs and issues to plan and provide effective health care programs for this growing group of clients.

Adult↗
PubMed1998

Training intensity-dependent and tissue-specific increases in lactate uptake and MCT-1 in heart and muscle.

We investigated the effects of 3 wk of moderate- (21 m/min, 8% grade) and highintensity treadmill training (31 m/min, 15% grade) on 1) monocarboxylate transporter 1 (MCT-1) content in rat hindlimb muscles and the heart and 2) lactate uptake in isolated soleus (Sol) muscles and perfused hearts. In the moderately trained group MCT-1 was not increased in any of the muscles [Sol, extensor digitorum longus (EDL), and red (RG) and white gastrocnemius (WG)] (P > 0.05). Similarly, lactate uptake in Sol strips was also not increased (P > 0.05). In contrast, in the heart, MCT-1 (+36%, P < 0.05) and lactate uptake (+72%, P < 0.05) were increased with moderate training. In the highly trained group, MCT-1 (+70%, P < 0.05) and lactate uptake (+79%, P < 0.05) were increased in Sol. MCT-1 was also increased in RG (+94%, P < 0.05) but not in WG and EDL (P > 0.05). In the highly trained group, heart MCT-1 (+44%, P < 0.05) and lactate uptake (+173%, P < 0.05) were increased. In conclusion, it has been shown that 1) in both heart and skeletal muscle lactate uptake is increased only when MCT-1 is increased; 2) training-induced increases in MCT-1 occurred at a lower training intensity in the heart than in skeletal muscle; 3) in the heart, lactate uptake was increased much more after high-intensity training than after moderate-intensity training, despite similar increases in heart MCT-1 with these two training intensities; and 4) the increases in MCT-1 occurred independently of any changes in the heart's oxidative capacity (as measured by citrate synthase activity).

Animals↗
PubMed1997

Lactate transport and lactate transporters in skeletal muscle.

The study of lactate transport in skeletal muscle had until recently been hampered by the lack of suitable sarcolemmal vesicle preparations. Researchers are now at the threshold of developing some very new understandings about the movement of lactate into and out of skeletal muscle with (a) evidence for a lactate transport system in skeletal muscle, (b) the very recent cloning of several monocarboxylate transporter genes, (c) the expression of at least one monocarboxylate transporter protein that facilitates the transport of lactate in heart and skeletal muscle, and (d) the realization that lactate transport can be altered with changes in chronic muscle activity. The MCT1 expression patterns in metabolically heterogeneous skeletal suggests that a primary role of this lactate transporter is to take up lactate into the oxidative muscle fibers where it may be used as a fuel in mitochondrial oxidation. Increments in both MCT1 and lactate transport with training support this role.

Animals↗
PubMed1996

Hepatocyte growth factor. A cytokine mediating endothelial migration in inflammatory arthritis.

OBJECTIVE: Angiogenesis is an integral component of the vasculoproliferative phase of rheumatoid arthritis (RA). Recently, a heparin-binding cytokine termed hepatocyte growth factor (HGF), or scatter factor (due to its ability to disperse cohesive epithelial colonies), was described. We conducted this study to investigate the hypothesis that this cytokine was present in the milieu of the inflamed joint, and that it contributed to the chemotaxis of endothelial cells in the synovial tissue. METHODS: We examined synovial fluid, synovial tissue, and peripheral blood from 91 patients with RA and other arthritides. We used 83 total samples in an enzyme-linked immunosorbent assay to quantitate the HGF in synovial fluids and peripheral blood. To determine whether the HGF was biologically active, an epithelial scatter factor assay was performed. Immunohistochemical analysis was used to determine localization in synovial tissues. To define a function for synovial HGF, we preincubated rheumatoid synovial fluids with neutralizing anti-HGF and measured the ability of these synovial fluids to induce endothelial chemotaxis. RESULTS: Synovial fluid from patients with RA contained a mean +/- SEM HGF concentration of 2.0 +/- 0.3 ng/ml, while synovial fluid from patients with other arthritides (including inflammatory arthritis) contained 2.4 +/- 0.7 ng/ml HGF. Osteoarthritis (OA) patient samples contained the smallest quantities of synovial fluid HGF at 0.9 +/- 0.1 ng/ml. RA synovial fluid contained significantly more HGF than did RA peripheral blood (1.1 +/- 0.2 ng/ml) (P < 0.05). Rheumatoid synovial fluids induced more scattering of cells than did OA synovial fluids, suggesting a role for this cytokine in rheumatoid joint destruction. Interleukin-1 beta induced expression of rheumatoid synovial tissue fibroblast antigenic HGF and scatter factor activity. Immunohistochemically, HGF, as well as the HGF receptor (the met gene product), localized to significantly more rheumatoid synovial tissue lining cells than normal lining cells (P < 0.05). Both HGF and its receptor immunolocalized to subsynovial macrophages as well. Levels of synovial tissue immunoreactive HGF correlated positively with the number of synovial tissue blood vessels. Anti-HGF neutralized a mean of 24% of the chemotactic activity for endothelial cells found in 10 rheumatoid synovial fluid samples. CONCLUSION: These results indicate that synovial HGF may contribute to the vasculoproliferative phase of inflammatory arthritides such as RA, by inducing HGF-mediated synovial neovascularization. These findings point to a newly described role for HGF in the fibroproliferative phase of RA-associated synovitis.

Arthritis, Rheumatoid↗
PubMed1996

Mediators, cytokines, and growth factors in liver-lung interactions.

Multiple mediators have been implicated in the interactions between the liver and the lungs in various disease states. The best characterized mediator of liver-lung interaction is alpha 1-antitrypsin. Several cytokines and mediators may be involved in the pathogenesis of the hepatopulmonary syndrome and in the cytokine cascades that are activated in systemic inflammatory states such as acute respiratory distress syndrome. Hepatocyte growth factor or scatter factor is a recently described peptide with a broad range of biologic effects that may mediate lung-liver interactions.

Cytokines↗
PubMed1980

Normal and exceptional children's attitudes toward themselves and one another.

In this study 65 junior high school boys and girls (54 normal and 11 exceptional children) evaluated themselves most favorably, normal children as a group less favorably, and exceptional children as a group least favorable of all on the Personal Attribute Inventory for Children. This was so regardless of whether the respondents were normal or exceptional children. Since data were collected from mainstreamed classrooms, it appears that mainstreaming may not be directly deleterious to exceptional children's self-concepts, but has associated with it a negative stigma for exceptional children as a group for both exceptional and normal children. These findings, plus others reported previously, fail to demonstrate that mainstreaming in its present form may be an elixir for exceptional children's social-emotional difficulties.

Adolescent↗