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Biomedical subjects

R Rodriguez

Publications and source records attributed to R Rodriguez.

At least 91 records · Page 5Linked to original sources
PubMed1987

Effect of nimodipine on arachidonic acid metabolites after subarachnoid hemorrhage.

Arachidonic acid metabolites are under investigation as possible vasoactive agents involved in the pathogenesis of cerebral vasospasm after subarachnoid hemorrhage. Prostaglandins, as well as other vasoactive compounds, activate contractile proteins through utilization of extracellular bound Ca++ to the intracytoplasmic free fraction. Recently, calcium-antagonists, mainly Nimodipine, have been proposed for the prophylaxis and/or reversal of the ischemic damage caused by vasospasm. Nimodipine failed to reduce vasospasm incidence in a series of 30 patients admitted with diagnosis of subarachnoid hemorrhage from ruptured intracranial aneurysm. Nimodipine failed to reduce level of four arachidonate metabolites measured (prostaglandin D2, prostacyclin, thromboxane B2 and leukotriene C4) in lumbar and cisternal CSF. After subarachnoid hemorrhage there is a significant increase of CSF levels of arachidonate metabolites; in perianeurysmic cisterns level of prostaglandin D2, thromboxane B2 and leukotriene C4 are significantly higher than lumbar CSF levels. Moreover, cisternal CSF level of prostaglandin D2 and leukotriene C4 are significantly higher in patients with symptomatic vasospasm. Nimodipine did not significantly modify CFS level of arachidonate metabolites: this suggests that Nimodipine treatment, which definitely improves long-term results of patients for intracranial aneurysms, could exert its pharmacological action reducing Ca++ intake from the extracellular compartment and preventing a direct toxic effect of calcium, without a direct action against the release of vasoactive compounds.

6-Ketoprostaglandin F1 alpha↗
PubMed1987

Influence of the qualitative caloric composition of enteral diets on liver protein synthesis in normal and operated rats.

Protein synthesis L-(l-14C) leucine in liver was studied. Normal (n = 40) and operated (n = 40) Sprague-Dawley rats with an initial body weight of 161.18 +/- 12 g were divided into four groups (n = 10), respectively. Each group, subjected to the same conditions of temperature, light, noise and movement received a different commercial formula for human enteral nutrition and water for 8 days (normal rats) and six days (operated rats). All rats received the same caloric and protein intake per ml (l kcal; 6-7.10(-3) g protein), with no statistically significant differences among groups. The differences in diets were merely qualitative. The tolerance to all diets was similar, with rats attaining the expected weight. Losses of protein, alpha aminic nitrogen, total fat and non sterified fatty acid in faeces were negligible. In normal rats, different results in liver protein synthesis were obtained. No mass/synthesis rate correlation was found. Under these conditions it would appear that these results are due to the different diets used. In operated rats, a significantly different liver protein synthesis per gram of body weight was obtained, but not per gram of organ weight. These results suggest that the influence of the qualitative caloric intake, in the stress phase, is less than in the normal state.

Animals↗
PubMed1987

Phosphatidylinositol depletion in GH3 rat pituitary cells inhibits sustained responses to thyrotropin-releasing hormone. Reversal with myo-inositol.

TRH stimulation of rat pituitary (GH3) cells causes biphasic changes in cytoplasmic free Ca2+ concentration [( Ca2+]i) and PRL secretion. It has been proposed, based primarily on indirect evidence, that the first phase effects are mediated by inositol 1,4,5-trisphosphate, which releases Ca2+ from cellular stores, and the sustained effects are mediated by 1,2-diacylglycerol, which activates protein kinase C. To determine more directly if inositol lipid hydrolysis leading to protein kinase C activation is involved in the sustained effects of TRH, GH3 cells were depleted of phosphatidylinositol (PtdIns) by prestimulation and incubation in myo-inositol-free, Li(+)-containing medium. Cells depleted of PtdIns (to 53 +/- 3.2% of control) had unchanged PtdIns 4,5-bisphosphate content, and responded to TRH with a rapid elevation of inositol trisphosphate, and a first phase (or burst) elevation of [Ca2+]i and PRL secretion that was not different from that found in control cells. In contrast, in PtdIns-depleted cells, the prolonged generation of inositol phosphates, which are produced in equimolar amounts with 1,2-diacylglycerol, caused by TRH was virtually abolished, and the second phase (or sustained) elevation of [Ca2+]i and PRL secretion were inhibited by 50% and 40%, respectively. The inhibition of both sustained effects was reversed by adding 100 mM myo-inositol to the medium, which allowed for synthesis of PtdIns. Last, in cells in which protein kinase C was down-regulated by pretreatment with a phorbol ester, the sustained effects of TRH were inhibited also.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Fine needle thyroid aspiration: university hospital experience.

Fine needle thyroid aspiration (FNTA) as a diagnostic tool of thyroid disease was started at the University District Hospital (UDH) in 1983. FNTA was performed in 54 willing patients from December 1984 through December 1985. If no medical contraindications existed, thyroid surgery was recommended in order to assess diagnostic accuracy. Surgery was done in 34 (63%) patients; while not in 20:3 for medical reasons, 2 lost to follow-up, 3 refused, 7 had inappropriate FNTA, and 5 for unknown reasons. None had complications to FNTA. Cytology was classified as Class O: inadequate; Class 1: benign; Class 2: indeterminate; and Class 3: malignant. "Non-benign" cytology was obtained in 14 patients: 7 indeterminate (class 2) and 7 malignant (class 3). Four of these had carcinoma confirmed by surgery. Of the 19 with benign FNTA (class 1) only one has thyroid carcinoma. One patient had inadequate sample (Class O). The sensitivity was 80%, specificity 65%, and diagnostic accuracy 67%. All these statistical values are within the range reported in fifteen reviewed series. Thus, FNTA at UDH had a diagnostic value comparable to that described in the literature. It may be utilized as a safe, reliable tool complementary to clinical data in order to reduce the amount of unnecessary thyroid surgery, carry out earlier diagnoses of malignant nodules and increase the yield of carcinoma among those operated.

Adenocarcinoma↗
PubMed1986

Human auditory steady state responses: effects of intensity and frequency.

Human auditory steady state responses were recorded in 41 normal subjects and 22 patients with hearing loss. The effect of intensity on the responses at different tonal frequencies was assessed using the sweep technique. The amplitude of the responses increases and the phase delay decreases with increasing intensity. Both the amplitude and the phase delay are smaller for high frequency tone bursts. Notched noise decreases the amplitude of the response by a factor of two but does not affect the phase of the responses. Thresholds were estimated in waking subjects using two techniques: intensity sweeps analyzed by linear regressions, and fixed intensities analyzed by Hotelling's T2 test. Frequency-specific thresholds obtained with notched noise were less variable and more accurate with the fixed intensity technique. In patients with sensorineural hearing loss the amplitude increased more with increasing intensity above threshold than in patients with conductive hearing loss.

Adult↗
PubMed1985

Amino acid sequence around the cysteine residues of pigeon egg-white lysozyme: comparative study with other type c lysozymes.

The cysteine-containing tryptic peptides of pigeon egg-white lysozyme have been purified by reverse-phase chromatography and thin-layer chromatography and electrophoresis on cellulose plates. They contain the eight cysteine residues of the protein. The amino acid sequence of these peptides reveals the existence of 24 differences in comparison to the homologous regions in hen egg-white lysozyme, among the 53 sequenced residues. The sequence data are compared to the corresponding ones in other type c lysozymes. According to this study, the pigeon lysozyme exhibits ten substitutions not observed in any other type c lysozyme. Pigeon lysozyme is the most different type c lysozyme from birds, according to the data on primary structure.

Amino Acid Sequence↗
PubMed1985

Microsurgical anatomy of the superficial veins of the cerebrum.

The microsurgical anatomy of the superficial cortical veins was examined in 20 cerebral hemispheres. The superficial cortical veins are divided into three groups based on whether they drain the lateral, medial, or inferior surface of the hemisphere. The veins on the three surfaces are further subdivided on the basis of the lobe and cortical area that they drain. The superficial cerebral veins collect into four groups of bridging veins: a superior sagittal group, which drains into the superior sagittal sinus; a sphenoidal group, which drains into the sphenoparietal and cavernous sinuses on the inner surface of the sphenoid bone; a tentorial group, which converges on the sinuses in the tentorium; and a falcine group, which empties into the inferior sagittal or straight sinus or their tributaries. The superior sagittal group drains the superior part of the medial and lateral surfaces of the frontal, parietal, and occipital lobes and the anterior part of the basal surface of the frontal lobe. The sphenoidal group drains the parts of the frontal, temporal, and parietal lobes adjoining the sylvian fissure. The tentorial group drains the lateral surface of the temporal lobe and the basal surface of the temporal and occipital lobes. The falcine group drains an area that includes the cingulate and parahippocampal gyri and approximates the cortical parts of the limbic lobe of the brain. The relationship of these veins to the venous lacunae was also examined.

Adult↗
PubMed1985

Amino acid sequence of pigeon egg-white lysozyme.

The amino acid sequence of pigeon egg-white lysozyme has been determined. The protein molecule contains a single polypeptide chain of 127 amino acid residues and exhibits only about 60% homology when compared to hen egg-white lysozyme.

Amino Acid Sequence↗