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Biomedical subjects

J D Benson

Publications and source records attributed to J D Benson.

At least 37 records · Page 2Linked to original sources
PubMed1990

Human cytomegalovirus induces expression of cellular topoisomerase II.

Previous work from our laboratory has suggested that topoisomerase II is required for replication of human cytomegalovirus (HCMV). In assays of confluent human embryonic lung cells infected with HCMV, topoisomerase II inhibitors exhibited an irreversible inhibition of viral DNA replication. However, Northern (RNA blot) and Western (immunoblot) analyses of confluent uninfected human embryonic lung cells detected very low levels of cellular topoisomerase II RNA and protein. Quantitation of human topoisomerase II RNA and protein levels at various times after HCMV infection revealed that HCMV induces increased intracellular levels of both topoisomerase II RNA and protein. Such accumulation began at early times of infection, continued through late in infection, and was not reduced by inhibition of viral DNA synthesis. This is the first report of such induction by a viral infection. Topoisomerase II was also detected in isolated HCMV virions.

Base Sequence↗
PubMed1989

Hypophosphatemia in breast-fed low-birth-weight infants following initial hospital discharge.

The present study evaluated 12 infants with birth weights less than 2000 g who received human milk plus a multivitamin supplement and 20 similar infants who received standard cow's milk formula for 16 weeks from the time of initial hospital discharge. Examination at birth, at hospital discharge (study entry), at 4 and 16 weeks after hospitalization, and at 52 weeks of age revealed no intergroup differences in body weight, length, and head circumference. Hypophosphatemia (plasma phosphorus concentration less than or equal to 1.45 mmol/L) developed in 6 infants fed human milk (5 infants at 4 weeks and 1 infant at 16 weeks of study). Mean vitamin D intakes, but not calcium and phosphorus intakes, were significantly lower during hospitalization in human milk-fed infants with hypophosphatemia (44 [25, SD] IU/d) compared with those without hypophosphatemia (322 [180] IU/d). These data indicate that human milk-fed, low-birth-weight infants are at risk for hypophosphatemia following initial hospital discharge. Plasma calcium, phosphorus, and alkaline phosphatase concentrations at hospital discharge may not predict the infants at risk. Vitamin D supplementation early in the infants' hospital course may prevent hypophosphatemia.

Alkaline Phosphatase↗
PubMed1989

Growth, serum biochemistries, and amino acids of term infants fed formulas with amino acid and protein concentrations similar to human milk.

We tested the hypothesis that amino acid intake from infant formulas modified to be similar to human milk would result in indices of protein metabolism more like those in human milk-fed infants. Formula-fed infants received for 12 weeks one of three isocaloric formulations of a whey-adapted formula that differed in protein concentration: 11, 13, or 15 g/L. Infants consumed similar volumes of formula or human milk. Serum urea nitrogen concentrations reflected the protein content of the diets. Plasma indices of protein nutritional status were normal and did not differ among groups. Growth rates of all infants were normal and similar. Serum indicators of protein nutritional status varied with age, which made comparisons of formula-fed infants with human milk-fed infants difficult. Plasma concentrations of leucine and isoleucine at 4 weeks of age were higher in infants fed the formula containing 15 g protein/L when compared with those of infants fed the other two formulas or human milk. At 8 and 12 weeks of age, all formula-fed infants had plasma amino acid profiles that did not differ significantly from each other except for isoleucine, which was lower in the 11-g/L group. We found that providing formulas with an amino acid pattern similar to that of human milk did not produce a plasma amino acid pattern identical to that of the breast-fed infant. This observation suggests that other factors, such as the hormonal response to feeding, differing nutritional bioavailability of amino acids from human and bovine milk proteins, and the changing quantity and type of amino acids with advancing lactation, influence plasma amino acid concentrations.

Amino Acids↗
PubMed1988

Two specific topoisomerase II inhibitors prevent replication of human cytomegalovirus DNA: an implied role in replication of the viral genome.

In this study, we show that human cytomegalovirus DNA synthesis is inhibited in infected confluent human embryonic lung cells treated with the DNA-intercalative topoisomerase II inhibitor 4-9'-(acridinylamino)methanesulfon-m-anisidide (m-AMSA). Similar inhibitory effects were observed with VM-26, a nonintercalative topoisomerase II inhibitor. This antiviral effect is not attributable to cytotoxic effects per se. Furthermore, m-AMSA appears to have a notably irreversible inhibitory effect on human cytomegalovirus DNA replication. No inhibition of viral DNA synthesis was observed with o-AMSA, a DNA-intercalative isomer of m-AMSA that does not inhibit topoisomerase II.

Amsacrine↗
PubMed1986

Nutrient intakes of older infants: effect of different milk feedings.

Using 24-hour dietary and nutrient intake of 293 infants 7-12 months of age from NHANES II, 1976-80, we determined the hypothetical effects of different milk feedings on total intake of 12 nutrients. Infants were grouped by age at 7-8, 9-10, and 11-12 months. Human milk (HM), Fe-fortified infant formula (I-FM), whole cow's milk (WCM), and 2% lowfat milk (2%) were substituted to provide the same energy as that calculated from the difference between median energy intake provided by solid foods and the total diet. Nutrients from milk feedings were added to median nutrient intake from solid foods. Use of WCM or 2% resulted in low total intakes of Fe (6.3-11.1 mg) and linoleic acid (0.5-2.5 g) and high intakes of protein (32-47 g), Na (630-1,200 mg), K (1,400-1,900 mg), and Ca (920-1,170 mg) relative to the RDA. Feeding of HM provided total intakes that met the RDA for each nutrient except Fe (6.1-10.8 mg) and Ca (350-370 mg). When I-FM was fed, the RDA was met for each nutrient except Ca (370-490 mg) at all ages and Fe (13.1 mg) at 11-12 months. Estimated safe and adequate daily intake of Na was exceeded at 9-10 months by infants fed WCM/2% and at 11-12 months by all infants regardless of milk feeding, primarily because of the high Na content of solid foods. These data confirm that the milk feeding is still the major determinant of total nutrient intake in the second 6 months of life.

Animals↗
PubMed1985

Malignant melanoma of soft parts: an ultrastructural study of four cases.

Malignant melanomas of soft parts from 4 patients were studied by light microscopy, immunocytochemistry for S-100 protein, and electron microscopy. Each patient presented with a deep soft tissue mass in an extremity. Histologically, the tumors were composed of epithelioid and spindle cells, and in one, neoplastic giant cells were present. The tumors did not stain for melanin but were all positive for S-100 protein. Ultrastructurally, premelanosomes were identified in every tumor and in a cell line established from one tumor. Schwann cell features were present in one of the tumors. Although the clinical presentation of malignant melanoma of soft parts is similar to that of epithelioid sarcoma and synovial sarcoma, the combined light microscopic, immunocytochemical, and ultrastructural features should serve to distinguish it from other soft tissue sarcomas.

Adult↗
PubMed1985

Nutrient intakes of formula-fed infants and infants fed cow's milk.

Twenty-four-hour dietary intake data from the second National Health and Nutrition Examination Survey (NHANES II), 1976-1980, were analyzed to compare nutrient intakes among infants 7 to 12 months of age who were fed mixed diets containing solid foods and either infant formula or cow's milk. Solid foods fed to the infants in both groups were low in iron and linoleic acid, and high in sodium, potassium, and protein, relative to Recommended Dietary Allowances. Infants who were fed cow's milk received lower median intakes of iron (7.8 mg v 14.9 mg), linoleic acid (1.8 g v 6.1 g), and vitamin C (39 mg v 64 mg), and higher median intakes of protein (41 g v 25 g), sodium (1,000 mg v 580 mg), and potassium (1,630 mg v 1,020 mg) than formula-fed infants. Seventy-five percent of the infants fed cow's milk had iron intakes below the Recommended Dietary Allowance; 69% had sodium intakes above the range of estimated safe and adequate daily dietary intake. Linoleic acid provided less than 3% of energy intake for 74% of the infants fed cow's milk. Differences in nutrient intakes were due not only to different concentrations of nutrients in each of the milk feedings but also to the different amounts and types of solid foods fed to the two groups of infants.

Animals↗
PubMed1981

IgD myeloma with intracytoplasmic crystalline inclusions.

Plasma cells from an IgD myeloma contained intracytoplasmic crystals. By electron microscopy, these crystals had 13-nm periodicity and were contained within vacuoles formed of smooth membranes. Immunofluorescence microscopy of the neoplastic plasma cells demonstrated diffuse cytoplasmic staining with accentuated Golgi region staining specific for immunoglobulin delta heavy and lambda light chains. The observations support an association between the crystal-containing vacuoles and the Golgi apparatus. Previously reported plasma cell and lymphocyte crystalline inclusions are reviewed, and compared with the crystals described in this report.

Aged↗
PubMed1977

Influence of diet on adiposal lipoprotein lipase and hepatic triacylglyceride synthetase activities in the developing pullet (Gallus domesticus).

1. Lipoprotein lipase activity of the abdominal fat pad and hepatic triacylglyceride synthetase activity were determined at 2, 7.5, 9, 12.5 and 20 weeks of age. 2. Specific activity of lipoprotein lipase in fat pad was constant at 2-9 weeks, decreasing until 20 weeks. Hepatic triacylglyceride synthetase activity decreased from 2 to 12.5 weeks, increasing by 20 weeks. 3. Lipoprotein lipase activity was higher throughout 20 weeks and triacylglyceride synthetase activity was higher at 7.5 weeks with energy restricted diet. 4. An inverse relationship existed between fat pad weight and specific activity of lipoprotein lipase; higher activity in adipose tissue of energy restricted pullets may have been a function of smaller fat pad size.

Adipose Tissue↗
PubMed1975

Lipoprotein lipase of ovarian follicles in the domestic chicken (Gallus domesticus) (38537).

A lipase, bearing the characteristics of adipose tissue lipoprotein lipase (LPL) has been characterized in avian ovarian granulosa cells. The activity is low in cells from follicles weighing less than 0.5 g; in heavier follicles which have entered the rapid growth phase, significant activity (1 mumole fatty acid/mg protein/hr) could be identified. Granulosa LPL provides follicular tissues with the requisite enzyme system to hydrolyze very low density lipoprotein triglyceride en route to the oocyte.

Adipose Tissue↗