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Biomedical subjects

M Grandolfo

Publications and source records attributed to M Grandolfo.

At least 37 records · Page 2Linked to original sources
PubMed1994

Energy metabolism, replicative ability, intracellular calcium concentration, and ionic channels of horse articular chondrocytes.

Some aspects of the physiology of chondrocytes from horse articular cartilage were studied, since this animal model can be helpful in understanding arthritic processes. The replicative ability of articular chondrocytes, measured by the incorporation of [3H]thymidine, and their capacity of proteoglycan production, evaluated from the incorporation of [35S] sulfate, are very low. In addition, these cells do not differentiate in vitro as shown by the constant specific activity of alkaline phosphatase measured at different times in culture. Two types of potassium channels were identified by patch clamp experiments in the cell-attached configuration, one characterized by a conductance of 40 pS and the other of 100 pS. No active K+ channels were found at Vpip = 0. It was shown by Fura-2 experiments that the low replicative ability is paralleled by a modest variation of the intracellular calcium concentration after a mitogenic stimulus. 31P NMR experiments, both on slices of whole articular cartilage and on isolated cells, demonstrate that chondrocytes derive their energy mainly from the glycolytic pathway.

Animals↗
PubMed1994

A static magnetic field does not affect the dielectric properties of chick embryo myoblast membranes.

We have recently demonstrated using dielectic relaxation studies in the radiowave frequency range that sinusoidal 50 Hz magnetic fields (with intensities ranging from 1 to 10 mT) induce a nonlinear change in both membrane conductivity and permittivity of primary chick embryo myoblasts in vitro. It was the aim of the present study to determine if a DC-induced static magnetic field is capable of generating similar variations in the membrane conductivity and/or the membrane permittivity of chick embryo myoblasts. The results indicate that when the myogenic cells are exposed to a static magnetic field of either 1, 3 or 5 mT (values comparable with the previous extremely low frequency study), no changes in the membrane electrical parameters can be observed with respect to controls. Differences in the characteristics of static and extremely low frequency fields as well as the possible mechanisms underlying the contrasting results with these two types of magnetic fields are discussed.

Animals↗
PubMed1994

Mercury exanthem.

We have observed 9 male patients with a generalized rash following the topical use of an over-the-counter antiparasitic powder (MOM), containing ammoniated (11.2 g%) and metallic (4.2 g%) mercury, to treat phthiriasis (lice infestation). Primary and intensely erythemato-exudative lesions of the pubic region and genitals were associated with inverted erythema of the upper inner thighs and, in severe cases, involvement of the face, neck, trunk and major flexures. Eruptions included exanthematic, papulo-vesicular, purpuric and erythema-multiforme-like clinical pictures. 7 of the 9 cases presented with general malaise and pyrexia. A positive patch test reaction to ammoniated mercury was observed in all cases. There are probably 3 routes of powder exposure behind this type of rash: (i) direct skin contact; (ii) airborne skin contact; (iii) inhalation.

Adult↗
PubMed1994

[International guidelines on the diagnostic applications of magnetic resonance. International Non-Ionizing Radiation Committee of the International Radiation Protection Association].

Magnetic resonance imaging has become an established diagnostic modality. The clinical usefulness of in vivo magnetic resonance spectroscopy was demonstrated in several instances and is being explored further. These techniques involve exposure of the patient to static and time-varying magnetic fields and radiofrequency electromagnetic fields. In particular exposure situations, these fields may pose a health hazard. The purpose of this paper is to provide information on the guidelines issued by the International Non-Ionizing Radiation Committee of the International Radiation Protection Association on levels of exposure and health effects from magnetic and radiofrequency electromagnetic fields associated with magnetic resonance diagnostic devices, and on precautions to be taken to minimize health hazards to patients undergoing magnetic resonance examinations.

Biophysical Phenomena↗
PubMed1993

Culture and differentiation of chondrocytes entrapped in alginate gels.

We studied the response to culture conditions and the differentiative ability in suspension culture in alginate gels of resting chondrocytes from the preosseous cartilage of adult pig scapula. It was found that the maximum rate of chondrocyte duplication is reached at the fourth day in culture whereas the rate of proteoglycan synthesis and alkaline phosphatase expression do not gain a maximum value before the seventh day. During the culture time, the chondrocytes undergo differentiation as it is demonstrated by the alkaline phosphatase specific activity increase and by morphological criteria (hypertrophy, increase of the number of mitochondria per cell, increased endoplasmic reticulum, matrix vesicle production). The alginate gels can be easily dissolved to obtain cell populations in which the variation of cytosolic calcium concentration following a proliferative stimulus can be conveniently observed using the conventional procedure of Fura 2.

Alginates↗
PubMed1993

Family planning in Italy.

In the past 5 years, four knowledge, attitude and practice (KAP) surveys on family planning have been organized by the Unit of Population Survey Methodology of the Istituto Superiore di Sanita' (National Institute of Health). These surveys show that during the past 20 years, use of reliable contraceptives in Italy has increased, particularly in the North, encouraged by the more open attitude toward sexual behavior, following legalization of the provision of information on contraception and abortion upon request, and other social and cultural changes. In 1989 and 1991, 25% of women in Central and Southern Italy were using the pill or an IUD. However, the percentage of women not using contraceptives was still high (26% in 1989, and 19% in 1991) and withdrawal was the most widely used method (31% and 33%). The data show large regional differences. The main reasons for not using contraception, in the 1989 study, were fear of side-effects and ignorance, especially in the youngest and oldest women. Those least likely to use modern contraception were the young, the ill-educated and the nulliparous women. Lack of information seems to be the main problem in Italy. In fact, the 5044 women interviewed showed a medium level of knowledge of contraception, with only 63% who could identify correctly the fecund period in the menstrual cycle. However, their attitude toward the use of modern contraception was positive; 65% of the women interviewed said they would recommend the Pill or an IUD to a friend, and 10% of them would recommend condoms.(ABSTRACT TRUNCATED AT 250 WORDS)

Abortion, Induced↗
PubMed1993

Thyroid hypofunction related with the progression of human immunodeficiency virus infection.

Thyroid function was evaluated in 119 human immunodeficiency virus (HIV) infected patients at different stages of infection, compared with euthyroid normal subjects and hepatitis C virus infected blood donors as control groups. The low T3 state, well documented in severe nonthyroidal illnesses, was not found in these HIV infected patients. They showed lower FT4 levels and higher TSH and TBG values than euthyroid normal controls. These findings suggested a thyroid hypofunction becoming more evident with the progression of the infection as also supported by the presence of antithyroid autoantibodies mainly found in the symptomatic stages of the infection.

Adult↗
PubMed1992

Calcium-activated potassium channels in chondrocytes.

The presence of calcium-activated potassium channels in chondrocytes of growing cartilage was tested. Results obtained with fura-2 on cultured resting chondrocytes indicate that the cells respond to an elevation of extracellular calcium concentration ([Ca2+]o) from 0.1 to 2 mM increasing the intracellular concentration of the ion ([Ca2+]i) from 117 to 187 nM. This increment may be blocked by 3 microM La3+. Patch clamp experiments in cell-attached configuration showed that, when [Ca2+]i rises, the open probability (Po) of the K+ channels increases. Increments in both Po and unitary currents of the K+ channels can be obtained after applying 2.5 microM A23187 with 2 mM [Ca2+]o. Hence, the results demonstrate that, in chondrocytes, a class of Ca(2+)-activated K+ channels is present and their activity is related to an increase of [Ca2+]i.

Animals↗
PubMed1992

[National Register of congenital hypothyroidism].

The results of five years activity of the National Register of children with Congenital Hypothyroidism (NRCH) have been evaluated. NRCH was established in Italy in 1987, as a pilot project of Health Ministry. All Italian Centers in charge of the screening, treatment and follow-up of CH are involved in the program. The results have provided further epidemiological informations about CH in Italy and have evidenced some aspects in the screening organization which had to be improved. Discussion of Register data in annual meetings has recently allowed to obtain an improvement especially for the beginning of treatment and the used dose of therapy.

Congenital Hypothyroidism↗
PubMed1992

[Anti-rubella vaccine coverage in women 11-28 years of age: data on 5 local socio-health units of Veneto].

Selective rubella vaccination in the 11 years old girls, has been carried out in the Regione Veneto (Venetian Land) since 1974. The rubella immunization rate in teh women born between 1962 and 1978, in five sanitary districts, is 68.25%; the trend of increasing vaccination is continuing. Important differences in the organization of vaccination campaign were found among the five districts.

Adolescent↗
PubMed1991

Energy state of chondrocytes assessed by 31P-NMR studies of preosseous cartilage.

The energy state of resting and hypertrophic chondrocytes from growth plate was studied by 31P-NMR spectroscopy of superfused cartilage slices. The presence of phosphocreatine was demonstrated in both cell types, using a repetition time of 3 s. By comparing the decline in the nucleoside triphosphate level after adding blockers of the glycolysis or of the mitochondrial respiration, it was deduced that resting and hypertrophic chondrocytes use both metabolic pathways for energy production, but the glycolysis dominates. Hypertrophic cells rely more on the mitochondrial respiration than the resting cells.

Animals↗
PubMed1991

Non-linear dependence of the dielectric properties of chick embryo myoblast membranes exposed to a sinusoidal 50 Hz magnetic field.

Primary chick embryo myoblasts can be a useful tool for studying the developmental events which accompany myoblast differentiation, particularly myoblast membrane fusion. To determine whether the electrical properties and/or fusion in these systems are affected by 50 Hz magnetic fields, chick embryo myoblast cultures were exposed to B-field intensities ranging from 1 to 10 mT. The electrical parameters of the myoblasts, i.e. membrane conductivity, membrane permittivity and the conductivity of the cell interior (cytosol) were determined by the analysis of conductivity dispersion data in the radio frequency range (10 kHz-100 MHz). Preliminary results indicate that the time of fusion (60 h) is not affected by these fields, but that the absolute values of the two membrane electrical parameters are affected. In particular, a B-field intensity-dependent decrease was observed. The maximum effect resulted after a 1 h exposure to a magnetic flux density of about 5 mT. The conductivity of the cytosol remained unchanged. These data seem to indicate that exposure to 50 Hz magnetic fields affects both static and dynamic membrane properties in primary chick embryo myoblasts.

Animals↗
PubMed1990

Magnetic resonance imaging: calculation of rates of energy absorption by a human-torso model.

The three-dimensional impedance method was used to estimate specific absorption rate (SAR) in a human-torso model during exposure to the time-varying and static magnetic fields used in magnetic resonance imaging (MRI). Analytical data for discrete tissues as well as the entire torso are presented. Generalized equations were derived that enable calculation of whole-torso SAR over a broad range of conditions. In addition, the impedance method can generate data about internal distributions of SAR, which are needed to predict critical organs that might undergo excessive elevations of temperature. Fair to good agreement was found between impedance-method SAR and those predicted by simple phenomenological models.

Electromagnetic Fields↗
PubMed1990

A potassium channel in cultured chondrocytes.

Chondrocytes, obtained from preosseous cartilage, were studied by patch clamp technique in cell-attached recording configuration, and single potassium channels were characterized at different stages of culture. After 3 days, outward currents were present, with an open probability increasing with depolarization, and the K+ channels showing a mean slope conductance of 82 pS in asymmetric and 168 pS in symmetric potassium solution. Tetraethylammonium (TEA) and quinidine blocked the channels. Cells at confluence showed similar channel activity, with conductances of 121 and 252 pS, respectively. We suggest that culture time and/or conditions may modify K+ channels or induce the expression of a new type of channels.

Action Potentials↗