Depression and loneliness symptoms in Brazilian older people during the COVID-19 pandemic: a network approach.

Objectives: Depression and loneliness in older people were a global challenge during the COVID-19 pandemic. Causal mechanisms to trigger depression might vary across different life events. We aimed to apply network analysis in a sample of Brazilian older people during the first wave of the COVID-19 pandemic, to investigate if loneliness and depression symptoms were connected within a psychological network.

The Calcium/Phosphorus Homeostasis in Chronic Kidney Disease: From Clinical Epidemiology to Pathophysiology.

Introduction: A simple data filtering process together with some basic concepts of control theory applied to electronically stored clinical data were used to identify some of the pathophysiological mechanisms underlying the perturbations of the calcium/phosphorus homeostasis in chronic kidney disease.

Material And Methods: Retrospective data (a set per patient of serum single value concentrations of creatinine, calcium, phosphorus, parathormone, 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D) from 2507 patients with stable chronic kidney disease not on renal replacement therapy were studied. The variables were paired and subjected sequentially to a moving average and partioned into frequency classes.

Transient modulation of calcium and parathyroid hormone stimulates bone formation.

Intermittent administration of parathyroid hormone can stimulate bone formation. Parathyroid hormone is a natural hormone that responds to serum calcium levels. In this study, we examined whether a transient increase and/or decrease in the serum calcium can stimulate bone formation.

[Cross-cultural adaptation of an instrument to evaluate older people's involvement in pleasant activities].

The sense of pleasure that arises from engagement in activities is a fundamental factor for wellbeing in the elderly. Brazil lacks an instrument to evaluate older people's involvement in pleasant activities. An American instrument was located in the international literature (The California Older Person's Pleasant Events Schedule - COPPES), evaluating the frequency with which older people engage in pleasant activities and the degree of pleasure they associate with each activity.

A mathematical model of calcium and phosphorus metabolism in two forms of hyperparathyroidism.

Parathyroid hormone (PTH) plays a critical role in calcium and phosphorus metabolism. Interestingly, in two forms of hyperparathyroidism (excessive amount of PTH in the serum), the metabolic disturbances in patients with chronic kidney disease (CKD) significantly differ from those with primary hyperparathyroidism (PHP). Since an intuitive understanding of these PTH-linked regulatory mechanisms are hardly possible, we developed a mathematical model using clinical data (1586 CKD and 40 PHP patients).

Model-Based Analysis of FGF23 Regulation in Chronic Kidney Disease.

The mechanism of FGF23 action in calcium/phosphorus metabolism of patients with chronic kidney disease (CKD) was studied using a mathematical model and clinical data in a public domain. We have previously built a physiological model that describes interactions of PTH, calcitriol, and FGF23 in mineral metabolism encompassing organs such as bone, intestine, kidney, and parathyroid glands. Since an elevated FGF23 level in serum is a characteristic symptom of CKD patients, we evaluate herein potential metabolic alterations in response to administration of a neutralizing antibody against FGF23.

Evaluation of the role of FGF23 in mineral metabolism.

Fibroblast growth factor 23 (FGF23) has recently been identified as a critical regulatory factor in phosphate (P) metabolism. Although the exact molecular mechanism of FGF23 synthesis through sensing the concentration of P is yet to be determined, experimental and clinical data indicate the influential role of FGF23 in P and calcium (Ca) homeostasis. Here, we extended our previous mathematical model in calcium regulation and examined the conceivable roles of FGF23 in mineral metabolism.

Inferring disease mechanisms from epidemiological data in chronic kidney disease: calcium and phosphorus metabolism.

Background/aims: By applying numerical filtering to epidemiological data of 2,512 chronic kidney disease patients, we aimed to identify some of the underlying mechanisms of the calcium/phosphorus metabolism perturbations.

Methods: The measured variables, serum calcitriol, calcidiol, total calcium ([Ca](s)) and phosphorus ([P](s)) and the urinary excretions of calcium and phosphorus, were paired in the same patients with the glomerular filtration rate (GFR) or the serum concentrations of parathormone (i[PTH](s)) (used as independent variables) numerically filtered with a moving average and partitioned into 15-25 frequency classes. All variables exhibited unimodal frequency distributions.

A mathematical model of the proton balance in the outer mantle epithelium of Anodonta cygnea L.

In the freshwater mollusc Anodonta cygnea and other unionids, the mantle plays an important role in the regulation of the movements of ions between the shell and the extrapaleal fluid. In this report, a mathematical model that attempts to describe the cell metabolic mechanisms underlying the operation of the outer mantle epithelium as a source of protons is presented. We encoded the information gathered by studying the epithelium in vitro, which includes the electrophysiology of the preparation, measurements of basic rates of transport of protons and base, the effect of metabolic and transport inhibitors on its electrical behavior and the dynamic measurements of pHi.

Knowledge, attitude and practice of breast self-examination in a female population of metropolitan São Paulo.

Objective: Evaluation of the knowledge, attitude and practice of breast self-examination in different groups of women in São Paulo.

Methods: Application of a questionnaire to 392 women divided in four groups. Group one: 101 patients of the National Health Service, Group two: 95 female physicians; Group three: 95 female medical students; and Group four: 101 wives of gynecologists.

A mathematical model of the diluting power of the cortical thick ascending limb of the loop of Henle.

A mathematical model is presented that describes the ionic transport across the cortical thick ascending limb (cTAL) of the Henle's loop, taking into account its tubular geometry. A comprehensive description of the cTAL is given for the first time in terms of potential, ion concentrations and ion fluxes along the tubule. For given ion concentrations at the entrance of the tubule, the model simulates steady-state profiles and allows the fitting of existing experimentally measured values at its exit.

A practical method for the detection of macroprolactinaemia using ultrafiltration.

Objective: The aim of this study was to evaluate a method for the estimation of the percentage of big-big prolactin (bb-PRL) in serum, based on centrifugal ultrafiltration (UF) and to be used for the detection of macroprolactinaemia.

Design: Serum samples were submitted to gel filtration chromatography (GFC), UF and precipitation with polyethylene glycol (PEG).

Patients: Serum samples obtained from 13 patients with macroprolactinaemia (Group 1) and from 15 hyperprolactinaemic patients without macroprolactinaemia (Group 2) were studied by the three methods.

A minimal mathematical model of calcium homeostasis.

A mathematical model of calcium homeostasis is presented in which the controlling factors are the plasma concentrations of calcium, PTH, and calcitriol, and the effector organs are the parathyroids, bone, kidney, and intestine. Other factors can be added as the need arises. The model is aimed at simulating what happens in a single individual, but its parameters and variables were adjusted to the corresponding published average values.

[Standardization of enzyme-linked immunosorbent assay ELISA to detect anti-Toxoplasma gondii IgM and IgG antibodies, and comparison with the indirect immunofluorescence technique].

Serology has been the most popular method to diagnose toxoplasmosis. Accordingly, this study standardizes an enzyme-linked immunosorbent assay (ELISA) and compares its results with the IFI technique. In the IgG detection test, the standardized technique presented a sensibility (S) of 96.

Chloride channels in the eel intestine.

Patches of freshly isolated epithelial cells from eel Anguilla anguilla intestine bathed by the same solution on both sides in the cell-attached configuration had conductances of 57.0+/-1.8 pS (for positive voltages) and 13.

[Relationships between basic sciences and medicine revisited].

1. The role of basic research in medical institutions and in particular in Medical Schools is discussed. 2.

[Curriculum planning. The direct way].

An attempt is being made in several Portuguese Medical Schools to reduce the Medical Course to five academic years. It will be easier and much more rigorous to base these changes on a detailed list of Educational Objectives. The choice of Educational Objectives must take into account the professional and social context surrounding the non-specialist physician (family doctor, general practitioner, etc), the background and maturity of the students, the manpower and resources of the Medical School and the results of the evaluation of the medical graduates as they finish their undergraduate training.

The effect of bile acid on the activation of amiloride-sensitive sodium channels in frog skin.

The effect of the bile acid, deoxycholic acid (DOC), on the transport properties of isolated frog skin was studied under short-circuit conditions. The addition of DOC (1 mM) to the apical side of the frog skin induced a threefold increase in the short-circuit current (Iac). This effect was inhibited by amiloride.

[Evaluation of medical schools and universities. Not postponable options, unavoidable risks].

1. The evolution of the relations between the Portuguese universities and the State is presented. It is considered that over the last 30 years the most important policies were the creation of new universities and the legal recognition of Ph.

[Role of formal education in the training of researchers: post-graduate education, masters, doctorates, and other standards].

The social function of Ph.D. graduates in the portuguese universities and scientific institutions is analyzed.

[Medical research in Portugal: the geniuses and the structures, the myths and common sense].

There was recently a growth in the funds allocated directly to scientific programs and projects and in particular to infrastructures (buildings and large pieces of equipment). It is very likely that this investment will continue to grow as a result of the development policies of the EEC applied to its less developed members. The recent experience with the Science Program, the main factor in this evolution, has demonstrated that the bottleneck in our scientific development is at the level of the allocation of funds (management).

Ion transport across the epithelium of the rabbit caecum.

The isolated rabbit caecum was studied in vitro. Under our experimental conditions, the rabbit caecum secreted potassium and chloride and absorbed sodium. To characterize the transport properties of the apical and the basolateral barriers, transepithelial electrical and flux (22Na, 36Cl and 86Rb) measurements and their sensitivity to transport inhibitors (furosemide, DIDS, ouabain and barium) are presented together with intracellular measurements with double-barrelled microelectrodes of intracellular electrical potentials and ionic activities.

A mathematical model of rabbit cortical thick ascending limb of the Henle's loop.

A mathematical version of the cell model of the cortical thick ascending limb of the rabbit proposed by Greger and Schlatter ((1983) Pfügers Arch. 396, 325-334) is described. Available data are sufficient to compute the most important parameters.

[Medical schools: training workshops?].

1--The aim of the medical course should be the training of doctors. 2--The advances in the medical sciences that took place over the last thirty years have caused profound changes in the professional, institutional and social aspects of medicine and in the professional profile of present doctors. Teaching of the basic sciences (biological and other) relevant to the medical sciences can not be done inside the medical course.

[The relation of basic sciences and medicine: institutional, professional and pedagogic implications].

The author analyses the problems involved in the transfer of concepts and techniques from the basic sciences to the medical practice. The number of skills to be acquired in the course of medical training restricts the inclusion of the teaching in depth of basic sciences in the Curricula of medical schools. Post-graduate teaching cannot be used for that purpose unless it is geared to MD's fully dedicated to research.