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F Meijide

Publications and source records attributed to F Meijide.

10 recordsLinked to original sources
PubMed2004

Successful prediction of the hydrogen bond network of the 3-oxo-12alpha-hydroxy-5beta-cholan-24-oic acid crystal from resolution of the crystal structure of deoxycholic acid and its three 3,12-dihydroxy epimers.

Crystal structures of p-xylene-crystallized deoxycholic acid (3alpha,12alpha-dihydroxy-5beta-cholan-24-oic acid) and its three epimers (3beta,12alpha-; 3alpha,12beta-; and 3beta,12beta-) have been solved. Deoxycholic acid forms a crystalline (P21) complex with the solvent with a 2:1 stoichiometry whereas crystals of the three epimers do not form inclusion compounds. Crystals of the 3beta,12beta-epimer are hexagonal, whereas the 3alpha,12beta-and 3beta,12alpha-epimers crystallize in the P2(1)2(1)2(1) orthorhombic space group. The three hydrogen bond sites (two hydroxy groups, i. e. O3-H, and O12-H, and the carboxylic acid group of the side chain, O24bO24a-H) simultaneously act as hydrogen bond donors and acceptors. The hydrogen bond network in the crystals was analyzed and the following sequences have been observed: two chains (abcabc... or acbacb... ) and two rings (abc or acb), which constitute a complete set of all the possible sequences which can be drawn for an intermolecular hydrogen bond network formed by three hydrogen bond donor/acceptor sites forming crossing hydrogen bonds. The orientation of O3-H (alpha or beta) determines the sequence of the acceptor and the donor groups involved in the pattern: O24a --> O12 --> O3 --> O24b when it is alpha and O24a --> O3 --> O12--> O24B when it is beta. These observations were used to predict the hydrogen bond network of p-xylene-crystallized 3-oxo,12alpha-hydroxy-5beta-cholan-24-oic acid. This compound has two hydrogen bond donor and three potential hydrogen bond acceptor sites. According to the previous sequence set, this compound should crystallize in the monoclinic P21 system, should form a complex with the solvent, O24b should not participate in the hydrogen bond network, and the chain sequence O24a --> O12 --> O3 would be followed. All predictions were confirmed experimentally.

Cholic Acids↗
PubMed2004

Specific aspects of erectile function in urology/andrology.

The urologist/andrologist is the specialist responsible for diagnosis and treatment of health problems related to the genitourinary tract, and his or her participation in comprehensive care for a patient with erectile dysfunction (ED) is fundamental and often indispensable. The urologists/andrologists should characterize the origin of ED because of their knowledge and familiarity of all diagnostic tests and second- and third-line therapy. The origin of ED is important to determine for various reasons, such as young people suitable for etiologic treatment, medicolegal reasons, or patients' wishes for a better understanding of their condition. A review of the diagnostic tests available as well as indications for second- and third-line therapy is presented. The close relationship between ED and urological disorders, such as benign prostatic hyperplasia, prostate cancer and their treatments, and renal failure, in association with penile conditions like Peyronie's disease, priapism, and possible androgen deficiency in men older than 50 years, places the urologist at the center of integrated treatment of male ED.

Attitude of Health Personnel↗
PubMed1996

Aggregation behavior of bile salts in aqueous solution.

Freezing point depression, delta T/k, and pNa are measured and analyzed for aqueous solutions of trihydroxy (NaTC) and dihydroxy (NaDC and NaTDC) bile salts. The results show the existence of break points in the plot of delta T/k vs molality at 0.018, 0.013, and 0.007 m, respectively, in good agreement with previous published critical micelle concentration values. Above the break point bile salts form aggregates with average aggregation numbers of 2.59 +/- 0.12 (NaTC), 5.82 +/- 0.04 (NaDC), and 5.42 +/- 0.47 (NaTDC). Fractions of bound counterions are also deduced, being close to 0.3 for the three bile salts studied. This indicates that only one counterion is bound for every three monomers in the aggregate. The different structural models published for the bile salt aggregates are discussed.

Bile Acids and Salts↗
PubMed1996

[PSA levels and its relationship with digital examination, age, and score of prostatic symptoms].

Between November 1992 and March 1993 our Service conducted a campaign for early detection of prostate disease among the male population of Vigo. The study focused in the relationship of PSA with the age, rectal examination and prostate symptomatology score. In view of the results obtained it has been concluded that PSA levels increase gradually as a function of age, volume and prostate symptomatology score.

Age Distribution↗
PubMed1995

[Enzyme-induced masculinization].

Contribution of two cases of congenital adrenal hyperplasia by blockade in the 21-hydroxylase enzyme synthesis. Diagnosis was reached from the clinical signs and symptoms (virilization syndrome), and was confirmed by radiological and laboratory tests. Hormone treatment was done with hydrocortisone and fludrocortisone, but surgical correction of external genitalia was required to improve cosmetic appearance.

Adolescent↗
PubMed1994

Aggregation behavior of sodium fusidate in aqueous solution.

We analyzed the freezing point depression and pNa measurements for aqueous solutions of sodium fusidate. At concentrations lower than 0.011 mol kg(-1), sodium fusidate behaves as a strong 1:1 electrolyte. At higher concentrations, sodium fusidate self-aggregates. To analyze the results two hypotheses on the monomer concentration are presented and discussed. The first one accepts that the monomer concentration, C(A), is constant and equal to 0.023 mol kg(-1). This concentration corresponds to a break point in the plot of the freezing point depression vs total sodium fusidate concentration, C(A)t. The second hypothesis accepts that C(A) increases with C(A)t following a leveling-off curve. Measurements of hydrodynamic radii and comparison with similar systems, such as sodium taurocholate, strongly support the second hypothesis. The results indicate that at concentrations lower than 0.08 mol kg(-1) the aggregation number increases from 2 to 3. Above this concentration, both the aggregation number and the fraction of bound counterions remain constant, with average values of 3.13 +/- 0.10 and 0.31 +/- 0.05, respectively. Such results indicate that for trimers only one Na+ counterion is involved per aggregate. We propose that this counterion shields the repulsion between the two nearest carboxylate groups which, according to a disklike model in which the monomers are packed with that group alternatively oriented up and down, should hold together. Values for the formation equilibrium constant of aggregates are also calculated. Its dependence with the aggregation number allows the determination of the reversible transfer of a free surfactant ion together with the associated counterions from the bulk solution to the aggregate, the resulting value being w(0) = -4.2k(B)T.

Anti-Bacterial Agents↗
PubMedDate not supplied

[Arachnoid cyst complicated by intracystic hemorrhage and spontaneous subdural hematoma: magnetic resonance findings].

Arachnoid cysts are collections of cerebrospinal fluid within the arachnoid membrane. They are benign lesions and most are congenital. They are usually asymptomatic; however, they can bleed and become symptomatic. Although arachnoid cyst associated to intracystic hemorrhage and spontaneous subdural hematoma is an uncommon complication, it is a well-known indication for emergency neurosurgery. We present the findings in a ten-year-old boy diagnosed with arachnoid cyst complicated by intracystic hemorrhage and spontaneous subdural hematoma diagnosed by magnetic resonance.

Arachnoid Cysts↗