PubMed Health⌕ Search

Biomedical subjects

M E Fonseca

Publications and source records attributed to M E Fonseca.

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

Changes in the prolactin serum isoforms secreted by a pituitary adenoma associated with therapy.

Variations in serum molecular forms of prolactin (PRL) from an adolescent woman presenting amenorrhea-galactorrhea are reported. Persistent hyperprolactinemia and hypoestrogenism were demonstrated as well as the presence of a pituitary tumor with suprasellar extension. Bromocriptine was given at progressive doses up to 37 mg daily, decreasing the hyperprolactinemia and galactorrhea. After 2 years of treatment the patient noticed symptoms of gastric intolerance, bromocriptine was discontinued and a rebound of hyperprolactinemia was observed. Lisuride was administered instead resulting in a new decrease in PRL serum levels, disappearance of galactorrhea and beginning of regular menses. Serum gel chromatographic analysis was carried out before and during lisuride treatment. The first chromatographic analysis showed a predominance of high molecular weight (approximately 66 KD) PRL, accounting for more than 90% of the immunoreactive PRL. The second chromatography showed the major peak of immunoreactive PRL displaced to the right (molecular weight of 22 KD), which was eluted near the PRL standard. With these chromatographic patterns it is concluded that the pituitary macroprolactinoma secreted different molecular forms of PRL and treatment with lisuride appeared to exert some effect on the PRL molecular size secreted by the pituitary.

Adolescent↗
PubMed1993

Interferon action on Mayaro virus replication.

Treatment of TC7 cells with interferon (IFN) drastically reduced the yield of infectious Mayaro virus under experimental conditions that virus attachment and penetration into the cells were not affected. In IFN-treated cells, synthesis of Mayaro virus proteins was inhibited and cellular protein synthesis was restored. This phenomenon is dependent on IFN concentration and multiplicity of infection. Electron microscopy of these cells revealed normal and anomalous viral particles inside cytoplasmic vacuoles. This suggests that IFN also interferes with Mayaro virus morphogenesis and inhibits the release of virions from cells.

Alphavirus↗
PubMed1993

Echovirus type 19 and herpes simplex type 2 infection in human placenta tissue explants.

1. Light and electron microscopy have been used to characterize echovirus 19 and herpes simplex type 2 infection of human placenta tissue in vitro. Immunofluorescence, autoradiography and virus adsorption were used to determine virus replication in this system. 2. Placental tissue was permissive to echovirus 19. Trophoblast cells were lysed with liberation of mature virions. However, during the 48-h period of observation, few cells were damaged and the trophoblastic structure was maintained. 3. HSV-2 infection in placental tissue was aborted although trophoblastic cells allowed virus adsorption, penetration and uncoating. A characteristic cytopathic effect was observed in infected trophoblastic cells in spite of the abortive infection.

Echovirus Infections↗
PubMed1993

[Determination of gastrin levels in maternal and neonatal serum as well as in amniotic fluid in acute fetal distress].

The objective was to measure gastrin (G) levels in maternal and neonatal sera as well as in amniotic fluid in patients with fetal distress and a control group. Twenty-five patients with term pregnancies were assigned to the following two groups: fifteen with acute fetal distress and ten with previous cesarean section. Maternal and neonatal blood and amniotic fluid samples were taken at the time of delivery. Differences between groups were calculated with non-parametric Mann Whitneys' U test. A significant difference (p < 0.001) between G levels in amniotic fluid of fetal distress and those of the control group was found. In conclusion, serum G levels can be used as another predictor of fetal distress, although further studies must be performed before it can be used as a clinical tool.

Acute Disease↗
PubMed1992

[Effect of primary ovarian insufficiency on the molecular heterogeneity of pituitary gonadotropins].

It is known that hypophysial gonadotropins circulate in different molecular forms which are provided with different biological activity and that the proportion of such varieties keep a relation with the concentrations of estrogens in circulation. In physiological menopause predominate the great molecular forms which have a lesser biological activity and when estrogens are administrated a change is produced to smaller molecular forms. The present study tries to determine if in cases of ovarian insufficiency of long duration as in precocious menopause and the syndrome of refractory ovary the chromatographic conduct of gonadotropin is similar. Six patients with precocious menopause, and three with the syndrome of refractory ovary, were studied, in order to make a comparison of chromatographic pattern of FSF and LH in serum, with the one found in women with normal ovarian function and with physiologic menopause. The chromatographic analysis was done by filtration in gel of the serum and the subsequent determination of LH and FSH by RIA of double antibody. It was found that the chromatographic pattern of patients with ovarian insufficiency of long duration, characteristically presents larger molecular forms, specially in the refractory ovary syndrome with a greater alteration in the profile of LH. With base on these results it is concluded that the duration of ovarian insufficiency determine the type of molecular form, predominant, of gonadotropins. Also it is suggested that for the syndrome of refractory ovary, the greater heterogenicity of gonadotropins may explain part of physiopathogeny.

Adult↗
PubMed1992

[The distribution of adipose tissue is related to the levels of insulin in the obese woman].

We studied 51 patients aged 20-35 years, with overweight or obesity evaluated by the body mass index (BMI = weight height2) when it was higher than 25 (normal 20-25), and a control group of six women with the same age and normal BMI. In all patients waist and hip circumferences were measured, to calculate the waist/hip ratio (WHR). Also serum insulin was measured in basal conditions and as response to 75 g oral glucose load, taking samples at 30, 60, 90, 120 and 180 minutes after. The test were performed 3 to 6 days following a spontaneous or induced genital bleeding with progestin. The WHR showed a normal distribution with the greatest frequency at 0.87. The patients were classified with predominance of adiposity in the upper body segment, when the WHR was equal or more than 0.85, and with adipose predominance in the lower body segment when it was equal or less than 0.84. The average insulin values in response to oral glucose load of patients with upper body segment obesity were significantly higher (Mann-Whitney's U = 0, p less than 0.02) than the corresponding cases with lower body segment obesity. Besides, there was a significant correlation between WHR and serum insulin values at 30 minutes after the oral glucose load (Pearson's r = 0.331, p less than 0.02). These results suggest a relation between the distribution of adiposity and insulin values, which were higher in patients with adipose predominance in the upper body segment.

Adipose Tissue↗
PubMed1991

Variations in the molecular forms of prolactin during the menstrual cycle, pregnancy and lactation.

Size heterogeneity of immunoreactive prolactin (PRL) was studied in serum samples obtained from eight normoprolactinemic women during the menstrual cycle and five additional patients at pregnancy and lactation. Gel filtration of sera from women with normal ovarian function tested at day 10-12th of their menstrual cycle showed two predominant PRL forms, approximately 22K and 26K mol wt. In addition two polymeric variants, 50K ("big" PRL) and 100K ("big-big" PRL) were found in less proportion, accounting for approximately 34% of the total PRL immunoreactivity detected in the sera. It was also noted a low mol wt form eluting around the region of 16K mol wt. In pregnant women the major PRL form was the 22K and its proportion showed a gradual increase as progression of gestation. The polymeric PRL forms were found in substantially less amount as gestation progressed. After parturition, in nursing mothers the 22K form remained prominent and in greater concentrations than the 26K monomeric variant. Large and low mol wt PRL forms were constantly detected in sera from women during the lactation period. From these data we confirmed that PRL circulates at various molecular forms and the relative proportion of these molecular variants exhibit changes according to the physiological state. In our study the predominant form was the 22K PRL (nonglycosylated) and it was of interest to discover the presence of a low mol wt PRL which elutes in the 16K area. The significance of this latter finding is not clear at the present.

Adult↗
PubMed1991

Synergism between electricity and ionizing radiation.

Weak direct electric currents which produce little (or no) lethal damage to Escherichia coli bacteria are shown to act synergistically with ionizing radiation, both electromagnetic radiation (X-ray) and charged particles (beta radiation). This synergism greatly enhances the lethal effect of ionizing radiation on bacteria. This is possibly due to increased single-strand breaks in DNA, as detected by the alkaline sucrose gradient method. It is also shown that in cells with thymidine-3H incorporated into their DNA and treated with electricity, the radioactivity is released from the acid-insoluble fraction to the acid-soluble fraction, so that the ratio of radioactivity in the soluble fraction to that in the insoluble fraction increases from 0.47 in the non-treated control cells to 3.46 in the cells treated with an electric current of 1.0 mA (3.0 V) for 30 min, which indicates extensive degradation of cellular DNA. No synergism is detected between electricity and 254 nm UV radiation nor between electricity and X-rays, when these two agents are used sequentially in any order. Electricity alone produces lesions in cell membranes, as shown by electron microscopy.

Beta Particles↗
PubMed1990

Congenital echo virus infection--morphological and virological study of fetal and placental tissue.

A prospective study of 78 pregnant women was undertaken to detect maternal enterovirus infection. Maternal faecal specimens and blood samples, placental and fetal tissue were taken for viral study, electron microscopy, histochemistry, and morphological examination. We present the post-mortem findings in three fetuses whose maternal infection was detected before delivery by isolation of ECHO virus type 33 and type 27 from faecal specimens and/or placental and fetal tissues. The morphological aspects were similar in all cases and included an acute infection of the placenta and hypoxic/hypotensive injury to fetal organs. In one case, viral particles were detected by electron microscopy of the fetal liver. This series of cases of intrauterine ECHO virus infection confirms the potential gravity of such infection during pregnancy and the need to prevent enteroviral disease.

Adult↗
PubMed1990

Ultrastructural study of Mayaro virus replication in BHK-21 cells.

The replication of Mayaro virus in BHK-21 cells was studied by electron microscopy. The infected cells show an intense vacuolization and proliferation of membranous structures. At 5 h post-infection, precursor virus particles were seen in the cytoplasm of infected cells. Later, mature virus particles were found outside the cells and budding from the plasma membrane. Enveloped virus particles were also observed inside the vesicles and budding across their membrane. The release of virus particles into the extracellular space by exocytosis was also observed. In a later stage of the infection, inclusion bodies were sometimes present in the cytoplasm of infected cells. We conclude that in BHK-21 cells, budding from the plasma membrane is the main process of Mayaro virus maturation, and in this kind of cell replication differs significantly from that observed in Aedes albopictus cells.

Alphavirus↗
PubMed1990

Ultrastructure of a spiral micro-organism from pig gastric mucosa ("Gastrospirillum suis").

The ultrastructural features of a helical-shaped bacterium occurring in the stomach of pigs, within the mucus on the mucosal surface of antral pits, were examined. The bacterial cell had three to eight spiral turns, flattened and truncated ends and was approximately 4.0 microns long and 0.6 microns wide. In some sections, up to six flagella, about 22 nm in diameter, were seen arising from each pole. The cytoplasm contained sparse, irregular granules, numerous ribosomes and large single-layered membrane-bound granules. In the flagella insertion area, there was a highly electron-dense component, the "polar membrane". This micro-organism differed from similar bacteria described in cats, dogs and monkeys, and may cause inflammation in the antral mucosa of pigs similar to Helicobacter pylori infection in man. Furthermore, it was morphologically similar to the spiral micro-organism distinct from H. pylori which has been described recently in human antral mucosa from patients with gastritis and may be of potential significance as a pathogen in man. The name "Gastrospirillum suis" is proposed for this bacterium.

Animals↗
PubMed1990

Enterovirus isolation from foetal and placental tissues.

Four spontaneous abortions and two stillbirth occurred during a prospective survey following the teratogenicity of echoviruses in 80 pregnant women selected at random from the Antenatal Care Service. Echovirus types 19, 27, and 33. Coxsackie B2 and B6 were isolated from placental and foetal tissues (brain, liver, kidney, heart, and spleen). The mothers also excreted the virus by faeces at least twenty days before abortion and responded serologically, indicating active virus infection. Almost all aborted children were anomalous with signs of viral infection.

Abortion, Spontaneous↗
PubMed1989

Replication of Mayaro virus in Aedes albopictus cells: an electron microscopic study.

The replication of Mayaro virus in Aedes albopictus cells, was studied by electron microscopy at various times post-infection. In infected cells we observed the presence of cytoplasmic vesicles containing viral nucleocapsids and mature virus particles but at no time did we detect virus budding into such vacuoles. Budding of virus through plasma membrane was rarely observed. Our results are discussed considering the possibility of the release of virus particles to the extracellular space by exocytosis.

Aedes↗
PubMed1989

[Ultrastructural aspects of Parkinson disease].

Brains from four parkinsonian patients and one control patient were analysed by electron microscopy. The most consistent abnormal findings were nerve fibers rarefaction, great interstitial space enlargement, neuropil disruption, mitochondrial tumefaction and degenerative changes. These findings occurred regularly in the brain of parkinsonian patients. Furthermore, except for mitochondrial changes, they were distinctively absent in the control patient, and therefore cannot be attributed to technical problems. Contrary-wise, they clearly reflect chronic neuronal loss. Also noteworthy was the demonstrative of deposits of amorphous substance into mitochondria, axons, cytoplasm and into the interstitial space.

Brain↗
PubMed1987

Long-acting bromocriptine for the acute treatment of large macroprolactinomas.

Six patients with hyperprolactinemia, visual impairment and large macroprolactinoma were treated with a long-acting bromocriptine, in dosage of 50 mg as a single im injection. All patients underwent a full assessment of pituitary prolactin (PRL) secretion before treatment and the studies were repeated about every week during 40 days. Following bromocriptine injection a rapid amelioration of the clinical and visual defects occurred in all patients. Likewise, a significant reduction of the hyperprolactinemia was documented in all six patients and in three of them serum PRL levels reached values as low as 20 ng/ml, and a tumor size reduction was demonstrated by cranial computerized tomography in three of the six cases. No side effects were associated with the administration of bromocriptine. From this study we conclude that the long-acting bromocriptine represents an additional option for the initial management of large prolactinomas in particular when they are associated with severe visual impairment.

Bromocriptine↗
PubMed1987

The significance of elevated levels of gastrin in patients with pituitary adenoma.

Six patients were studied with pituitary adenomas and elevated concentrations of gastrin similar to those found in cases of benign antral gastrinoma syndrome. Chromatography of the serum using Sephadex-G50 revealed different molecular forms of gastrin according to the type of adenomas. In those cases of acromegaly and gonadotrophinoma, gastrin-34 and unsulphated gastrins constitute the predominant forms. In contrast, in cases of Cushing's disease, gastrin-17, sulphated as well as non-sulphated were the predominant types; the chromatographic pattern was similar to that observed in two patients with antral gastrinoma syndrome who acted as controls. These findings demonstrate that pituitary adenomas might secrete gastrin. Taking into account that gastrin-34 and unsulphated gastrins were the predominant forms in cases of acromegaly, gonadotrophinoma and non-functioning adenoma, it is assumed that those molecular forms are mainly produced in the anterior lobe of the hypophysis. Conversely, gastrin-17 was the principal molecular form in cases of Cushing's disease confirming the close relationship of the synthesis of gastrin and corticotrophin peptides. The cases with Cushing's disease exhibited a serum gastrin pattern similar to that observed in the two cases with antral syndrome in which the predominant immunoreactive form of gastrin in gastrin-17 exhibiting a degree of sulphation corresponding to that of antral gastrin. It is concluded that the circulating excess of gastrin originated in the pituitary tumour tissue and the molecular form varied with the type of pituitary adenoma.

Adenoma↗
PubMed1986

Impaired glucose tolerance coincides with abnormal release of growth hormone following a glucose load as well as in response to TRH in acromegaly.

It is known that some acromegalic patients exhibited a paradoxical release of growth hormone (GH) after glucose administration. We have attempted to investigate a relationship between the paradoxical GH secretion with the abnormal glucose tolerance test present in some cases of acromegaly. We also studied the inappropriate increase in GH levels following thyrotropin releasing hormone (TRH) injection which is present in some acromegalics. We found that only those patients who had an abnormal glucose tolerance test exhibited simultaneously, the paradoxical release of GH, moreover, the same patients showed GH release following TRH administration. This observation suggests that some acromegalics have an abnormality in their hypothalamic glucose receptor and such abnormality is associated with abnormal GH secretion when TRH is administered. On basis of these findings it is suggested that the hypothalamus may play an important role in the pathogenesis of acromegaly in these cases.

Acromegaly↗