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Biomedical subjects

C Anderson

Publications and source records attributed to C Anderson.

At least 559 records · Page 31Linked to original sources
PubMed1982

Anation of laccase type 2 copper by azide and thiocyanate ions.

A mechanistic study of the anation of type 2 Cu(II) in fully oxidized laccase by azide and thiocyanate ions (X-) is reported. The rate data support a mechanism involving rapid formation of an outer-sphere complex (laccase . X-) followed by rate-limiting dissociative interchange to give the inner-sphere complex (laccase-X-) product: (formula; see text) Rate parameters for the laccase-azide reaction are k'2 = 1.25 X 10(-1) s-1 and k'-2 = 1.50 X 10(-2) s-1; those for the laccase-thiocyanate reaction are k'2 = 2.0 X 10(-2) s-1 and k'-2 = 1.1 X 10(-2) s-1 (25 degrees C, pH 6.1 phosphate buffer, I = 0.5 M). Although the rate law for anation of type 2 Cu(II) by N3- in 2-(N-morpholino)ethanesulfonic acid (Mes) or acetate medium (kobsd = k3 + k4[N3-]) differs from that observed in phosphate buffer, the data may still be accounted for in terms of the above mechanism, with Kos[N3-] much less than 1 [in Mes, k3 = 2.2 X 10(-2) s-1 and k4 = 3.3 X 10(-1) M-1 s-1; in acetate, k3 = 2.1 X 10(-2) s-1 and k4 = 3.4 X 10(-1) M-1 s-1 (25 degrees C, pH 6.0, I = 0.25 M)]. The equilibrium and spectroscopic characteristics of the laccase type 2 Cu(II)-N3- complex are compared with those of low molecular weight copper(II)-azide species, and the factors responsible for the very low substitutional reactivity of the type 2 cupric ion are discussed.

Anions↗
PubMed1982

Sulconazole nitrate 1.0 percent cream: a comparison with miconazole in the treatment of tinea pedis and tinea cruris/corporis.

Sulconazole nitrate 1.0 percent cream was compared to miconazole nitrate 2.0 percent cream in a double-blind, parallel study involving ninety-six patients with cutaneous dermatophytosis. Both agents were highly effective, with no statistically significant differences in the parameters studied. Among tinea pedis patients, all of seven treated with sulconazole and six of nine treated with miconazole were mycologically cured (negative culture and potassium hydroxide test) at the end of four weeks of twice a day treatment, and there were no relapses by week 9. Among tinea cruris/corporis patients, the rates of mycological cure after three weeks of twice a day treatment with sulconazole or miconazole were, respectively, twenty-nine of thirty-two (91 percent) and 100 percent of thirty one (accompanied in all cases by complete or significant clearing of signs and symptoms); the respective relapse rates were four of twenty-five (16 percent) and eight of twenty-three (35 percent). Miconazole resulted in two cases of severe irritant dermatitis requiring discontinuation of treatment, whereas sulconazole produced no severe irritant reactions.

Adolescent↗
PubMed1982

Radiographic studies on bone in beagles subjected to low levels of dietary lead since birth.

This experiment studies the effects of low-level oral lead administration on bone in standardized colony-raised research male Beagles. Lead was administered to lactating mothers from parturition through weaning and directly to the pups thereafter. Results of bone radiographic morphometric and bone radiographic densitometric findings in five experimental and four control animals are reported. Total femoral length, and femoral diaphysal width, combined with cortical thickness, thickness/width ratio, and radiographic photodensitometry did not vary significantly between both groups, although bone lead and blood lead levels were significantly higher in the experimental group.

Absorptiometry, Photon↗
PubMed1982

Radiographic morphometry and radiographic photodensitometry of the femur in the Beagle at 13 and 21 months.

A study was made of x-ray morphometry and x-ray photodensitometry of bones of 2 small groups of healthy standardized colony-raised male research Beagles, ages 13 and 21 months. The morphometry and photodensitometry results were correlated to other variables of interest. The total width of the femur and its optical density to x-rays increased significantly with age and body weight, but not so the length of the femur nor the combined cortical thickness (CCT). This last measurement (CCT) did not increase in parallel with the whole length of the bone either. The CCT/width ratio decreased as body weight increased. The clear-cut increase in the optical density of the whole bone is therefore explained by the age-related variations in bone envelope activity.

Absorptiometry, Photon↗
PubMed1981

Biosynthesis and secretion of chorionic gonadotropin subunits by organ cultures of first trimester human placenta.

The biosynthesis and secretion of human chorionic gonadotropin (hCG) have been studied by pulse-chase labeling techniques in organ cultures of normal first trimester placentae. As we previously reported for human malignant trophoblastic cells (Ruddon et al. (1981) J. Biol. Chem. 256, 5189-5196), first trimester placental tissue produces Mr = 18,000 and 15,000 intracellular forms of alpha subunit and Mr = 24,000 and 18,000 forms of beta subunit. In the placental tissue, there is a greater accumulation of mature subunit forms prior to secretion. The predominant intracellular form of alpha subunit in placental tissue is a high mannose, (Man)8(GlcNAc)2 oligosaccharide-containing form just as it is for malignant trophoblastic cells; however, in placenta there is evidence for a greater content of partially processed intermediates with oligosaccharides smaller than (Man)8(GlcNAc)2. Placental tissue secretes both a large free alpha subunit and an hCG-alpha subunit that is part of complete hCG, but there is a 3- to 6-fold greater secretion (on a molar basis) of free alpha than complete hCG. There is no evidence for the synthesis of high molecular weight prohormone forms that might be precursors to the secreted forms of hCG subunits.

Carbohydrate Conformation↗
PubMed1981

A single gonadotropin alpha-subunit gene in normal tissue and tumor-derived cell lines.

The structure of gene sequences coding for the mRNA of human chorionic gonadotropin (hCG) alpha-subunit was investigated by Southern blot analysis of genomic DNAs using a cloned, full length cDNA probe. While four hormones, lutropin, follitropin, thyrotropin, and choriogonadotropin, have homologous alpha-subunits, only one gene that bears hCG-alpha sequences could be detected per haploid complement. The structure of this single gonadotropin alpha-subunit gene, which contains intervening sequences, is the same in DNA from first trimester and term placentae. However polymorphism was observed for the presence of a HindIII site and of an Eco RI site in the gene's 3' flanking sequences. The organization of hCG-alpha sequences in several trophoblastic and nontrophoblastic tumor cell lines, which produce hCG subunits, was also examined. In each, the same gene copy number and structure were seen as in normal tissue. Thus, the characteristics of ectopic alpha-subunit expression in these cells seem not to be determined by DNA rearrangements.

Cell Line↗
PubMed1981

Contrast sensitivity and central vision in reattached macula.

Macular functions were studied in patients recovering after surgery for retinal detachment involving the macula. Central vision was assessed by visual acuity, grating acuity, metamorphopsia, and contrast sensitivity tests for 5 months up to 3 years post-operatively. Impairment of contrast sensitivity was generally observed at high and intermediate spatial frequencies as compared to age-matched controls. In 2 cases, both with low visual acuity, an attenuation was also found at low spatial frequencies. Reductions of visual and grating acuity were closely related indicating that the test target for acuity determination is of minor importance in evaluating recovery in retinal detachments. The majority of the patients studied had different degrees of metamorphopsia. The reduction of the contrast sensitivity at intermediate spatial frequencies corresponded to the reduction in acuity. Our study thus presents no evidence for a selective vulnerability of specific contrast channels unrelated to acuity loss.

Adult↗
PubMed1981

Analysis of granulocyte beta-adrenergic response in cystic fibrosis: correlation of decreased responsiveness with disease severity.

Granulocytes from 21 nonasthmatic cystic fibrosis (CF) patients were isolated and the effects of isoproterenol, histamine, and prostaglandin E1 upon zymosan-induced beta-glucuronidase release was measured. Granulocytes from CF patients contained significantly less total beta-glucuronidase activity compared with those from control subjects, but response to zymosan stimulation was normal. Compared with those from control subjects, the granulocytes from CF patients with severe airway disease (% predicted FEV1 less than 60) had significantly reduced responsiveness to isoproterenol, which correlated with both the % predicted FEV1 values and the NIH clinical score. In this same population of CF patients, granulocyte responsiveness to PGE1 was also decreased compared with that of the control subjects, but the degree of impairment was not as severe as that observed with isoproterenol nor did it correlate with disease severity. Histamine responsiveness, however, was normal. Our findings suggest that abnormal beta-adrenergic responses may reflect the severity of airway disease and clinical score.

Adolescent↗