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Biomedical subjects

S S Baker

Publications and source records attributed to S S Baker.

At least 55 records · Page 3Linked to original sources
PubMed1985

Relationships between in vitro selenium supply, glutathione peroxidase activity, and phagocytic function in the HL-60 human myeloid cell line.

Utilizing the HL-60 human promyelocytic leukemia cell line cultured in defined medium, we examined the quantitative and temporal relationships between Se supply and the activity of the selenoenzyme glutathione peroxidase, as well as the effects of selenium deficiency on phagocytic function. Glutathione peroxidase activity depended on the medium Se concentration up to 2.6 X 10(-8) M (sodium selenate, 5 ng/ml), above which a plateau occurred. HL-60 cells grown in medium without Se supplementation became GSH peroxidase deficient, with activity 1-3% that of Se-replete cells. Replenishment of the medium with sodium selenate returned enzyme activity to 23% that of replete cells by 24 h and to 85% by 7 days, a process blocked by cycloheximide. Se-deficient HL-60 cells induced to granulocytic differentiation by dimethylformamide showed decreased hexose monophosphate shunt activity in response to phorbol myristate acetate and to an exogenous enzymatic H2O2-generating system. However, Se-deficient and -replete cells showed equal responses to methylene blue, which stimulates the shunt independently from the glutathione cycle. Se-deficient mature HL-60 cells stimulated with phorbol myristate acetate released 2.3-fold more H2O2 than Se-replete cells and only slightly (not significantly) less O2. Se-deficient and -replete differentiated HL-60 cells did not differ significantly in their capacities for cell motility or for ingestion of serum-opsonized bacteria. Differences between the findings of the present study and previous in vivo rat studies may reflect both the defined in vitro environment of the cell line and the inverse ratios of catalase and glutathione peroxidase activities in human and rat granulocytes.

Cell Line↗
PubMed1985

Selenium repletion and glutathione peroxidase--differential effects on plasma and red blood cell enzyme activity.

We studied three children with chronic gastrointestinal disease who had been on intravenous hyperalimentation for periods of time ranging from 4 to 23 months. Each child was found to have low plasma and red blood cell glutathione peroxidase activity. This was associated, in the two children tested, with a marked deficiency of serum selenium. Their plasma glutathione peroxidase levels ranged between 4 and 24% of normal and their red blood cell levels ranged between 4 and 14% of normal. The intravenous alimentation was then supplemented with sodium selenite (240 micrograms Se/d). Within 4-5 weeks, the plasma glutathione peroxidase activity returned to normal. Red cell glutathione peroxidase activity remained essentially unchanged for 4-6 weeks, after which it increased over the following 3-4 months. Red cells were separated by density on a continuous Percoll-diatrizoate gradient. In normal individuals, the specific activity of glutathione peroxidase did not differ across the gradient despite a 2.5-fold difference in the specific activity of pyruvate kinase. When studied initially, glutathione peroxidase activity from the deficient patients did not change across the gradient. As the red cell enzyme activity increased with selenium repletion, the highest specific activity was initially found at the top of the gradient (youngest cells). After 3-4 months of supplementation, the specific activity became equal across the gradient. Thus, with selenium repletion, there is a rapid increase in plasma glutathione peroxidase activity, a 4-6 week lag prior to an increase in red cell enzyme activity, and the increase in red cell activity is due to newly synthesized red cells made in the presence of selenium.

Erythrocyte Aging↗
PubMed1984

Carbon dioxide laser blepharoplasty.

An experience utilizing the carbon dioxide laser for blepharoplasty in a series of 40 patients with an average follow-up of 16 months is reported. The advantages of this method include improved control of intraoperative hemorrhage which occurs because the laser cauterizes small vessels as it cuts tissues. Postoperative ecchymosis and edema are minimal and early rehabilitation occurs. Complications and technical disadvantages are discussed, concluding that the carbon dioxide laser offers a safe alternative with some distinct intraoperative and postoperative advantages to conventional blepharoplasty surgery.

Blepharoptosis↗
PubMed1984

Increased sensitivity to H2O2 in glutathione peroxidase-deficient rat granulocytes.

The role of glutathione peroxidase (GSH-Px) in protecting phagocytic function of peritoneal granulocytes (PMN) was assessed using selenium (Se)-deficient rats. Rats fed an Se-deficient diet for 12-15 weeks developed profound Se deficiency. Their PMN were found to contain 11% of control levels of GSH-Px. Previous studies have shown that at this level of enzyme activity, the metabolism of H2O2 via the glutathione cycle was impaired. Despite this, the initial rate of phagocytosis, as measured by the ingestion of opsonized oil red O particles, was normal. Prior incubation of PMN in an H2O2-generating system resulted in a time-dependent loss in the ability of the cells to ingest. GSH-Px-deficient PMN were affected to a greater degree than control PMN. Degranulation, as measured by the release of beta-glucuronidase into the extracellular medium after stimulation of PMN by opsonized zymosan in the presence of cytochalasin B, was unaffected by GSH-Px deficiency. Prior incubation of PMN in an H2O2 generating system resulted in decreased degranulation in both control and GSH-Px-deficient PMN, with GSH-Px-deficient PMN being affected to a greater degree. The killing of Staphylococcus aureus 502A by both control and GSH-Px-deficient PMN was the same. There was no effect of prior H2O2 incubation on bacterial killing in either control or GSH-Px-deficient PMN. Thus, GSH-Px appears to be important in protecting those aspects of phagocytic function that are sensitive to the destructive properties of exogenous H2O2.

Animals↗
PubMed1983

Selenium deficiency with total parenteral nutrition: reversal of biochemical and functional abnormalities by selenium supplementation: a case report.

A patient with multiple intestinal fistulae maintained on total parenteral nutrition for 18 months developed low serum selenium. Erythrocyte glutathione peroxidase activity was 6% of normal. Erythrocytes were not able to metabolize H2O2 as well as those from controls, although the hexose monophosphate shunt itself was intact. Granulocytes from this patient had 15% of the erythrocyte glutathione peroxidase activity found in normals. Patient granulocytes were not able to metabolize H2O2 as well as controls, although the hexose monophosphate shunt was intact. Erythrocyte glutathione peroxidase-deficient granulocytes incubated with a respiratory burst stimulant, phorbol myristate acetate, had only 60% of the hexose monophosphate shunt activity present in control granulocytes. These abnormalities were reversed with selenium supplementation. Bacterial killing of Staphylococcus aureus 502A and cardiac function were not affected by selenium deficiency. Thus, selenium deficiency resulted in biochemical and functional abnormalities of erythrocytes and granulocytes. These abnormalities were reversed with selenium supplementation.

Adult↗
PubMed1983

Altered oxidative metabolism in selenium-deficient rat granulocytes.

Rats fed a selenium-deficient diet for 12 to 15 wk became selenium-depleted, measured by the selenium content of liver and granulocytes. The activity of granulocyte glutathione peroxidase, a selenoenzyme, in deficient rats was 11% of the activity in replete rat granulocytes. When stimulated with an H2O2 generating system, the HMPS activity of the deficient granulocytes was 50% of replete; however, when stimulated with methylene blue, the HMPS activity in deficient and replete granulocytes was the same. When granulocytes were incubated with PMA or OPZ, deficient granulocytes initially had the same O-2-generating activity as replete granulocytes; however, with increasing duration of stimulation, granulocytes from deficient rats generated less O-2 than replete rats. After 20 min in an H2O2-generating system, deficient granulocytes stimulated with PMA or OPZ generated less O-2 than replete granulocytes. These results indicate that deficient granulocytes did not metabolize H2O2 as well as replete granulocytes and that H2O2 caused damage to the O2-generating system. Measurement of O-2 generation in membrane-enriched particles showed the above effects were due to inactivation of the NADPH-dependent O2-generating system. Deficient granulocytes stimulated with OPZ for 20 min had 70% less membrane O-2-generating activity than controls. In addition, when membrane-enriched particles were made from cells that had been stressed with an H2O2-generating system, NADPH-dependent O-2-generating activity in deficient granulocytes was 50% of replete. In selenium-deficient granulocytes with low GSH-Px activity, prolonged incubation with stimulants and prior incubations with an H2O2-generating system caused loss of activity of the membrane-bound, NADPH-dependent, O-2-generating system.

Animals↗
PubMed1978

Successful use of a soya-maize mixture in the treatment of kwashiorkor.

Forty-eight children aged 5 years or less admitted consecutively with a clinical diagnosis of kwashiorkor were randomly allocated to two groups. One group was treated with milk while the other group was fed soya-maize porridge; both groups received the same supportive treatment. The recovery rate in both groups was comparable. Protein intake and the rate of rise in serum albumin and transferrin concentrations were greater in the milk-fed group. The incidence of diarrhoea was significantly less in the children fed soya-maize. Soya-maize porridge is recommended as an effective and inexpensive treatment for kwashiorkor.

Animals↗
PubMedDate not supplied

Antioxidant enzymes in the differentiated Caco-2 cell line.

Injury to the gastrointestinal tract by oxygen dependent processes is important in ischemia, inflammatory bowel disease, and necrotizing enterocolitis. The Caco-2 cell line is an important tool in assessing various gastrointestinal functions and offers a unique opportunity to assess gastrointestinal oxidant metabolism on a cellular level. However, some Caco-2 cell functions change with time after confluence. To determine if antioxidant enzyme activity changes during differentiation, Caco-2 cells were grown to confluence, and superoxide dismutase, glutathione peroxidase, glutathione reductase, and catalase activities and specific mRNA content were quantitated. With time after confluence the enzymes demonstrated a small, but statistically significant increase in activity. Neither superoxide dismutase nor glutathione peroxidase mRNA levels correlated with enzyme activity changes. Catalase mRNA levels increased as catalase activity increased. Thus, differentiated Caco-2 cells express superoxide dismutase, glutathione peroxidase, glutathione reductase, and catalase activities and the superoxide dismutase, glutathione peroxidase, and catalase genes. Superoxide dismutase activity and glutathione peroxidase activity do not correlate with mRNA levels, and suggest that regulation may be at a level other than transcription. The correlation between catalase activity and catalase mRNA suggests differentiation may occur at transcription. If Caco-2 cells are used to elucidate oxidative metabolism, changes in activities of antioxidant enzymes as a function of cell differentiation should be considered.

Adenocarcinoma↗
PubMedDate not supplied

Short-term malnutrition in neonatal rabbits. I. Brush border enzymes.

Seventy-two hour starvation in neonatal rabbits was studied. Fasted animals received no feeds, only water every 8 h for 72 h. Fed animals were suckled by the dam. There was no difference in birth weight, serum albumin, blood urea nitrogen, electrolytes, or urine specific gravity between fed and fasted animals. Weight at 72 hr was less in fasted (p less than 0.01) than fed rabbits. Serum cortisol (p less than 0.05) and corticosterone (p less than 0.01) levels were higher in the fasted group. Proximal and distal small bowel homogenates had less DNA and protein (p less than 0.01) in the fasted group, but the protein/DNA ratio was the same in the proximal and distal small bowel homogenates from both groups. Sucrase (E.C.3.2.1.26) specific activity was significantly increased in proximal small bowel homogenates from the fasted group (p less than 0.01) but was the same in distal small bowel homogenates from both groups. Sucrase total activity per proximal segment was the same in fed and fasted animals but was significantly less per segment in distal small bowel homogenates from fasted animals. Alkaline phosphatase (E.C.3.1.3) total and specific activity was decreased in proximal (p less than 0.01) and distal (p less than 0.05) small bowel homogenates from the fasted group. Lactase (E.C.3.2.1.23) total activity was decreased in proximal and distal (p less than 0.01) small bowel homogenates from the fasted group but lactase specific activity was unchanged. Thus, a brief period of malnutrition in neonatal animals can result in a variety of regional functional changes in the gastrointestinal mucosa.

Animals↗
PubMedDate not supplied

Reversal of biochemical and functional abnormalities in erythrocytes secondary to selenium deficiency.

A patient with multiple enterocutaneous fistulae on total parenteral nutrition for 14 months developed low erythrocyte selenium and low erythrocyte glutathione peroxidase. Erythrocyte hexose monophosphate shunt activity stimulated with an H2O2 generating system was approximately one-fourth that of control. Hexose monophosphate shunt activity stimulated with methylene blue showed little difference between patient and control. With selenium supplementation erythrocyte selenium, glutathione peroxidase, and hexose monophosphate shunt activity became normal. Thus, the biochemical and functional consequences of selenium deficiency can be corrected with selenium supplementation.

Adult↗
PubMedDate not supplied

Metabolic derangements in children requiring parenteral nutrition.

Intravenous alimentation is routinely used in many hospitalized pediatric patients, however, there are few reports of the nature and frequency of metabolic complications. In order to assess the frequency and nature of metabolic complications all children receiving parenteral nutrition from January 1, 1982 to December 31, 1982 were prospectively enrolled in the study. Data collection began with the institution of parenteral nutrition. Serum electrolytes, minerals, liver function tests, and renal function tests were followed weekly. A total of 201 patients received parenteral nutrition for 5378 days. Nutrition was delivered to 146 patients (4980 patient days) via a central line and 55 patients via a peripheral line (398 patient days). The sepsis rate was 3.7% in central lines used only for parenteral and 4.8% in multipurpose central lines. In general, complications were fewer in the patients supported peripherally. In patients supported centrally, hypoalbuminemia was the most commonly found abnormality followed by hypocalcemia, hypophosphatemia and hypomagnesemia, reflecting a malnourished state. One-third of the patients had abnormal liver function tests, and in half of those factors causing liver dysfunction other than parenteral nutrition were present. Abnormal renal function tests occurred in 10% of the patients. Thus, a high incidence of metabolic complications occurred in association with parenteral nutrition. Most were present during the initiation of parenteral nutrition, suggesting an abnormal metabolic state was present prior to the institution of parenteral nutrition. The frequency of low serum albumin and minerals is consistent with previous publications of the prevalence of malnutrition in hospitalized patients.

Adolescent↗
PubMedDate not supplied

Teaching transcultural nursing in a transcultural setting.

The application of Leininger's Theory of Culture Care Diversity and Universality to the dialogue between students and faculty regarding nursing education and practice provides the theoretical framework for evaluating a transcultural nursing curriculum in a transcultural, transnational setting on the Texas-Mexico border. In evaluating the first semester of this cultural encounter between the nurse-patient-community system and baccalaureate nursing education, faculty and students at Texas A&M International University School of Nursing in Laredo identified some particular challenges and assessed the effectiveness of approaches to meeting these challenges within the context of Leininger's Culture Care Theory and its three modes of action: culture care preservation, accommodation, and repatterning.

Cultural Diversity↗