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D Merritt

Publications and source records attributed to D Merritt.

10 recordsLinked to original sources
PubMed2001

No supermassive black hole in M33?

We observed the nucleus of M33, the third-brightest galaxy in the Local Group, with the Space Telescope Imaging Spectrograph at a resolution at least a factor of 10 higher than previously obtained. Rather than the steep rise expected within the radius of gravitational influence of a supermassive black hole, the random stellar velocities showed a decrease within a parsec of the center of the galaxy. The implied upper limit on the mass of the central black hole is only 3000 solar masses, about three orders of magnitude lower than the dynamically inferred mass of any other supermassive black hole. Detecting black holes of only a few thousand solar masses is observationally challenging, but it is critical to establish how supermassive black holes relate to their host galaxies, and which mechanisms influence the formation and evolution of both.

Journal Article↗
PubMed2000

Raloxifene and estrogen effects on quality of life in healthy postmenopausal women: a placebo-controlled randomized trial.

OBJECTIVE: To assess the effects of raloxifene, estrogen, and placebo on quality of life in healthy, asymptomatic, postmenopausal women. METHODS: In a multicenter, double-blind, 12-month study, 398 women were assigned randomly to one of four groups: raloxifene HCl, 60 (n = 97) or 150 mg/day (n = 100); conjugated equine estrogens, 0. 625 mg/day (n = 96); or placebo (n = 105). The Women's Health Questionnaire, a validated quality-of-life instrument for perimenopausal and postmenopausal women, was administered at baseline and 3-month intervals. RESULTS: Overall, quality of life from baseline to end point was preserved equally in all treatment groups. Six domains (depressed mood, somatic symptoms, memory/concentration, sexual behavior, sleep problems, and perceived attractiveness) were unchanged in all groups. Three domains (menstrual symptoms, vasomotor symptoms, and anxiety/fears) were statistically significantly different among groups. Mean scores for menstrual symptoms significantly worsened and vasomotor symptoms significantly improved from baseline to end point in the estrogen group. Mean scores for vasomotor symptoms did not worsen at any point in the raloxifene 60 mg/day group. Mean anxiety/fears scores improved significantly during raloxifene 60 mg/day administration throughout treatment (P <.05), irrespective of previous hormone replacement therapy, baseline estradiol (E2) levels, or years postmenopause. CONCLUSION: Most quality-of-life domains were not affected by treatment with estrogen or raloxifene. Estrogen provided relief from vasomotor symptoms but caused menstrual symptoms. Raloxifene 60 mg/day improved anxiety levels in postmenopausal women.

Climacteric↗
PubMed1997

Hb Seal Rock [(alpha 2)142 term-->Glu, codon 142 TAA-->GAA]: an extended alpha chain variant associated with anemia, microcytosis, and alpha-thalassemia-2 (-3.7 Kb).

Hb Seal Rock was first reported in a young African-American women and her 2-year-old daughter (1). It is an extended alpha chain variant which, like Hb Constant Spring, is present in small quantity and is expressed as an alpha-thalassemia. The mutation, TAA-->GAA affects codon 142 of the alpha 2 gene. In this family, the index case was a compound heterozygote for Hb Seal Rock trait and for alpha-thalassemia trait (-3.7 kb). Her hematologic expression was similar to mild Hb H disease, presumably because the Seal Rock mutation affects the alpha 2 gene that is normally responsible for approximately 70% of alpha-globin synthesis. Her daughter had only Hb Seal Rock trait, but was phenotypically alpha-thalassemia-2 trait due to the expression of the Seal Rock mutation on one of her alpha 2-globin genes, the other three alpha-globin genes being unaffected.

Adult↗
PubMed1976

An evaluation of the usefulness of amylase isozyme differentiation in patients with hyperamylasemia.

Amylase assays measure total activity without differentiating the relative contributions of pancreatic- and salivary-type amylase isozymes. Since polyacrylamide electrophoresis allows identification of salivary-and pancreatic-type isoxymes and their respective variants, serum and urine specimens from patients with the clinical diagnoses of mumps (4), pancreatitis (16), or undiagnosed hyperamylasemias (5) were compared with specimens from control subjects. Patients with mumps had elevations of salivary-type isozymes, while those with pancreatitis had elevations of pancreatic-type isozymes. Elevation of salivary-type isozymes was identified in the five patients who had undiagnosed hyperamylasemias; among these, the isozymes of two originated in neoplastic ovarian tissue and those of three, probably in the salivary glands. Amylase isozyme differentiation cannot unamibiguously identify the tissue source of hyperamylasemia. However, in patients whose hyperamylasemia is of unknown etiology or who respond atypically to therapy, amylase electrophoresis provides identification of the elevated isozyme type, thus providing the basis for the rational selection of further diagnostic procedures.

Aged↗