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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Temporal relationship between bone loss and increased bone turnover: A longitudinal study following natural menopause
No full textWe report the results of a longitudinal study aimed at better defining concomitant changes of both bone mineral density (BMD) and of four independent markers of bone turnover (serum osteocalcin, serum alkaline phosphatase activity, fasting urinary hydroxyproline/creatinine and calcium/creatinine ratio) following natural menopause. The results obtained indicate that, within a relatively short period of time since cessation of gonadal function, conventional markers of bone turnover behave differently. In fact, while the mean values of hydroxyproline/creatinine ratio (felt to be a marker of bone resorption) rise immediately at the first control (19.7+/-11.7 months), the bone formation markers gradually increase and, as far as serum osteocalcin levels are concerned, this increment appears to be long-lasting. As a result of these changes, a negative skeletal balance follows, which is documented by the prolonged reduction of bone mineral density during the entire observation period. Mean+/-SD % measured yearly bone loss was -2.83+/-2.6. There was a highly significant correlation between initial and final BMD values (r = 0.908, p<0.001; r(2)= 82.5) and a weak inverse correlation (r = -0.298, p<0.046) between initial serum alkaline phosphatase values and % yearly bone loss. In conclusion, measurement of the biological indices of bone remodelling following natural menopause indicate that the increase in osteogenesis is delayed compared to that of bone resorption; furthermore, in the immediate postmenopausal period, the actual bone mass should be considered the best predictor of future bone mass. The inverse correlation found between % yearly bone loss and serum alkaline phosphatase values seems to emphasize the importance of increased bone turnover as an independent predictor of bone loss
Significance of early increase in stable and radioactive plasma calcium after parathyroidectomy in primary hyperparathyroidism
No full textEarly effects of parathyroid hormone (PTH) deficiency were studied in 12 patients with primary hyperparathyroidism due to single parathyroid adenoma by following the precise time course of changes in plasma calcium (Ca) and immunoreactive parathyroid hormone (iPTH) after parathyroid surgery and by prelabeling 2 patients with radiocalcium (Ca*). Surgical removal of the adenoma was immediately followed by a sudden increase in plasma Ca which preceded the usual fall. The increase in plasma Ca commenced simultaneously with the fall in iPTH and was accompanied by a parallel increase in specific activity (sp. act.) of plasma Ca*. Specific activity continued to rise for 2 h in both prelabeled patients, whereas blood calcium was already falling thereafter reaching a markedly low removal rate constant as long as plasma Ca decreased. When plasma Ca began to rise, sp. act. resumed a descending course. Our findings indicate that the initial hypercalemia depends on PTH withdrawal and results from a rapid flux into general extracellular fluid (ECF) of calcium coming from a compartment with higher sp. act., contained within the miscible pool, immediately followed by a reduction in calcium transfer from bone. These results suggest that acute PTH deficiency determines an outflow of calcium from bone cells and support the theory that PTH initiates its action by modifying their intracellular calcium content. © 1979 Springer-Verlag
Biochemical picture accompanying sclerotic bone metastases of prostatic origin.
No full textThis study was carried out to evaluate the metabolic consequences of osteosclerotic skeletal metastases of prostatic origin in a homogeneous group of patients. We found significantly increased mean values of serum alkaline phosphatase activity and significantly reduced mean values of serum phosphate, 24-h urinary calcium, fasting calcium excretion and TmP/GFR in cancer patients with respect to age-matched controls. Mean serum immunoreactive parathyroid hormone (iPTH) levels were raised, with two patients showing increased values of the hormone above our normal limits. Our findings indicate that mild secondary hyperparathyroidism is a feature of these patients. However, it cannot be excluded that both the reduced serum phosphate and TmP/GFR values may be related, at least in some cases, to the effects of the tumour itself on tubular reabsorption of phosphate
SERUM CARBOXY-TERMINAL PROPEPTIDE OF HUMAN TYPE-I PROCOLLAGEN IN PATIENTS WITH PRIMARY HYPERPARATHYROIDISM - STUDIES IN BASAL CONDITIONS AND AFTER PARATHYROID SURGERY
No full textThis study was carried out in order to evaluate serum carboxy-terminal propeptide of human type I procollagen (PICP) in patients with primary hyperparathyroidism and to examine its changes following parathyroidectomy. Seventeen patients (four males and 13 famels, aged 53.8 +/- 3.1 SEM years) were studied in basal conditions; six patients also were investigated after successful parathyroid surgery. Mean serum PICP values of patients with primary hyperparathyroidism (194.5 +/- 27 SEM mu g/l) were significantly higher (p < 0.001) with respect to those found in normal subjects. However, deviations from the norm (Z score values) were significantly less with respect to deviations of serum osteocalcin, alkaline phosphatase and urinary hydroxyproline/creatinine ratio. Following parathyroidectomy, it was possible to observe a discrepancy between markers of bone resorption and those of bone formation. The former tend to decrease, while the latter either do not show any significant change (serum alkaline phosphatase and serum osteocalcin) or increase (serum procollagen). The results of our investigation indicate that in basal conditions the assay of serum procollagen may be of clinical value but it would be better to use it in combination with other biomarkers of skeletal remodelling. The results obtained after parathyroidectomy are the opposite of those obtained following parathyroid hormone infusion and should be ascribed to the effect of acute hormone deficiency on collagen synthesis. The positive biochemical uncoupling following surgery might lend support to the rise of bone mineral density consistently reported in the first few months following parathyroidectomy
Calcitonin secretion and bone disease severity in hypercalcaemic hyperparathyroidism
No full textCalcitonin (CT) plasma levels and urinary hydroxyproline (OHPr) excretion were studied in twenty-eight patients (eleven males and seventeen females) with primary hyperparathyroidism in order to ascertain the effect of CT secretion on the severity of bone disease. The results show that in primary hyperparathyroidism plasma CT levels are increased in about 50% of patients independent of sex. Plasma CT levels were correlated with serum calcium values in males but not in females. Urinary OHPr excretion values appeared higher in those patients which showed lower CT plasma levels. In this latter group the incidence of undetectable CT plasma values was higher in females. The results suggest that in patients with primary hyperparathyroidism the persistent challenge of CT secreting parafollicular cells due to chronic hypercalcemia, may induce a decrease in their functional reserve, and that the bone involvement may have a greater incidence and more severe course in females, due at least in part, for their inability to increase CT secretion as much as males, due to an intrinsic sex-related lower CT secretory reserve
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
[Studies of the half-life of plasma parathyroid hormone: rate of disappearance of immunoreactive fragments of the hormone after surgical removal of the parathyroid adenoma in primary hyperparathyroidism].
No full textThe disappearance rate of immunoreactive plasma parathyroid hormone (iPTH) was studied, employing two different antisera, following removal of parathyroid adenoma in patients with primary hyperparathyroidism. One antisera contained antibodies against both the NH2 region and the COOH terminal of the molecule (antiserum 211/32, Wellcome Laboratories), the other contained antibodies against antigenic sites of the terminal COOH portion (Immuno Nuclear Corporation antiserum). The iPTH plasma level dropped in all patients following removal of the adenoma. The half-life was longer than that of the native hormone and shorter than that of the terminal fragment with both antisera, being 38.8 min for the 211/32 and 32.9 min for the I.N.C. antiserum. Whilst this finding might be expected for the 211/32 antiserum, on account of its characteristics, it is difficult to offer an explanation for the observed half-life of the I.N.C. anti serum which is specific for the terminal COOH region. These results appear to suggest that the terminal COOH fragment may be further metabolized and that its longer half-life, observed by other authors, is due to the antisera used recognizing the antigenic sites in a fragment smaller than the terminal COOH portion of the molecule, rather than to the effective half-life of the entire fragment
SERUM OSTEOCALCIN IN PRIMARY HYPERPARATHYROIDISM - SHORT-TERM EFFECT OF SURGERY
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