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Biomedical subjects

B Molina

Publications and source records attributed to B Molina.

At least 19 recordsLinked to original sources
PubMed2005

Trisomy of the short arm of chromosome 5 due to a de novo inversion and duplication (5)(p15.3 p13.3).

Partial trisomies of the short arm of chromosome 5 are uncommon. The first description was made by Lejeune et al., in 1964. It has been suggested that the critical region for 5p trisomy syndrome lies between 5p10 and 5p13. We report on a Mexican girl who developed severe mental retardation and generalized tonic clonic seizures at age 1 year. On physical examination at age 5 years, she had macrodolichocephaly, upslanted palpebral fissures, bilateral inner epicanthic folds, low nasal root, and malformed ears with posterior rotation which are clinical characteristics of 5p trisomy syndrome. The cytogenetic study with G bands and FISH with painting for chromosome 5 and with the cri-du-chat 5p15 unique sequence probe showed a duplication and inversion of 5p [46,XX, dup(5)(p15.3 p13.3)] which overlaps with the critical region for 5p trisomy syndrome. Our patient shares clinical characteristics with the patients described in the literature with involvement of this critical region. Both parents have normal karyotypes indicating the rearrangement is de novo. Only one patient has been reported in the literature with the same cytogenetic rearrangement as our patient, but this patient had a different phenotype. Since they only performed conventional cytogenetics and we performed FISH to confirm the diagnosis, the differences in the phenotypes could be explained by the presence of other genes involved in the rearrangement. The combined use of conventional and molecular cytogenetics in this case allows a more precise diagnosis and furthers knowledge in phenotype/genotype correlation.

Abnormalities, Multiple↗
PubMed2002

The clastogenic response of the 1q12 heterochromatic region to DNA cross-linking agents is independent of the Fanconi anaemia pathway.

Fanconi anaemia (FA) is a rare genetic syndrome of cancer susceptibility characterized by spontaneous and induced chromosome fragility, especially after treatment with cross-linking agents. Recent investigations showed interactions between FA proteins and chromatin remodelling factors. To investigate a potential uneven distribution of the FA pathway through the human genome depending on chromatin conformation, we have analysed chromosome breakage in the largest constitutively heterochromatic region in the human genome, the 1q12 band, in lymphocytes from FA patients, carriers and healthy controls after treatment with the cross-linking agents mitomycin-C (MMC) and diepoxybutane (DEB). As expected, a higher level of MMC-induced cytotoxicity and chromosome breakage was observed in cells from FA patients when compared with normal controls and carriers. However, the increase in 1q12 breakage after increasing concentrations of MMC was of a similar magnitude in FA patients, carriers and controls. Similarly, DEB induced a high level of overall genome chromosome fragility in cells from FA patients when compared with controls with no parallel increase in chromosome breaks specifically involving the heterochromatic band 1q12. We therefore conclude that, unlike the overall genome, the sensitivity of chromosome 1 constitutive heterochromatin to the chromosome breaking activity of cross-linking agents is independent of a functional FA pathway, indicating that the action of the FA pathway is unevenly distributed through the human genome.

Case-Control Studies↗
PubMed2001

Spatial distribution of Reissner's fiber glycoproteins in the filum terminale of the rat and rabbit.

The subcommissural organ secretes into the third ventricle glycoproteins that condense to form the Reissner's fiber (RF). At the distal end of the central canal of the spinal cord, the RF-glycoproteins accumulate in the form of an irregular mass known as massa caudalis. Antibodies against RF-glycoproteins and a set of lectins were used at the light and electron microscopic level to investigate the spatial distribution of the massa caudalis material in the rat and rabbit filum terminale. In the sacral region of the rat, the central canal presents gaps between the ependymal cells through which RF-glycoproteins spread out. The bulk of massa caudalis material, however, escapes through openings in the dorsal wall of the terminal ventricle. In the rabbit, the massa caudalis is formed within the ependymal canal, at the level of the second coccygeal vertebra, it accumulates within preterminal and terminal dilatations of the central canal, and it escapes out through gaps in the dorsal ependymal wall of the terminal ventricle. The existence of wide intercellular spaces and a large orifice (neuroporous) in the dorsal ependymal wall of the terminal ventricle, and the passage of RF-material through them, appear to be conserved evolutionary features. After leaving the terminal ventricle of the rat and rabbit, RF-glycoproteins establish a close spatial association with the numerous blood vessels irrigating the filum terminale, suggesting that in these species the blood vessels are the site of destination of the RF-glycoproteins escaping from the central canal, thus resembling the situation found in lower vertebrates. When passing from the RF stage to the massa caudalis stage, the rabbit RF-glycoproteins lose their sialic acid residues, exposing galactose as the terminal residue. Since this sialic acid-galactose modification of RF-glycoproteins had also been described in lamprey larvae, it may be regarded as a conserved evolutionary feature associated with the formation of the massa caudalis.

Animals↗
PubMed1999

Genotoxic studies of vanadium pentoxide (V(2)O(5)) in male mice. II. Effects in several mouse tissues.

Vanadium pentoxide (V2O5) was tested for its ability to induce genotoxic damage in six different organs (liver, kidney, lung, spleen, heart, and bone marrow) of mice by using the alkaline Single Cell Gel Electrophoresis (SCGE) assay. Animals were sacrificed 24 h after i.p. administration of the vanadium pentoxide of 23.0, 11.5, or 5.75 microg/g (corresponding to the LD50, 1/2 LD50 and 1/4 LD50, respectively). In all tissues and organs evaluated (except for bone marrow), V2O5 increased the number of cells with damage. Our results showed that i.p. injection of V2O5 induced DNA damage in different organs and tissues, and that this kind of damage can be observed even 24 h after treatment. The analysis of DNA migration and the distribution of DNA damage showed that there are differences in sensitivity between organs and tissues to this compound. In addition the sensitivity of SCGE assay allows the detection of long term DNA damage and the possibility to compare it in various tissues and target organs.

Animals↗
PubMed1999

Determination of normative criteria and validation of the SKT for use in Spanish-speaking populations.

Most of the tests, questionnaires, and neuropsychological batteries for the assessment of dementia have been translated and adapted for use in the Hispanic population without having normative data, which results in a high number of false positives when age and educational level are not considered. The Short Cognitive Performance Test (SKT) is a psychometric instrument evaluating memory and attention deficits that has been developed and standardized in Germany (Erzigkeit, 1989a, 1989b). The objective of this study was to adapt the SKT, to establish normative criteria that take into consideration age and educational level, and to establish its concurrent validity in comparison to other neuropsychological tests: Brief Neuropsychological Evaluation for Spanish-Speaking Subjects (Ostrosky-Solis et al., 1994), the Mini-Mental State Examination (Folstein et al., 1975), and the Blessed Functional Scale (Blessed et al., 1968) in 238 neurologically intact subjects and 97 subjects with mild to moderate dementia. The SKT showed adequate sensitivity (80.5%) and specificity (80.3%) in subjects with medium and high educational level; however, the sensitivity and specificity diminished (75% and 56.7%) in subjects with no education or low educational level. The adapted and validated version of the SKT in the Mexican population has been shown to be a psychometric instrument that in subjects with medium educational level can detect cognitive alterations and is able to determine the severity of deterioration; however, in subjects with low educational level and severe dementia, the SKT cannot be usefully administered.

Aged↗
PubMed1997

Chromosome instability with bleomycin and X-ray hypersensitivity in a boy with Nijmegen breakage syndrome.

We report on a Mexican boy with microcephaly, short stature, and a high frequency of chromosome aberrations with rearrangements involving chromosomes 7 and 14, typical of ataxia telangiectasia (AT) patients. He had neither ataxia nor telangiectasia, and his immunological status and serum alpha feto protein (AFP) level were normal. Bleomycin hypersensitivity, which has been demon-strated in AT patients, was tested in the patient using AT and normal subjects for comparison. The frequency of spontaneously occurring chromosome aberrations in lymphocyte cultures was significantly higher in the patient and the AT patient than in the normal subject. Four cells from the patient showed structural rearrangements involving chromosomes 7 or 14, with breakpoints typical for AT. When exposed to 5.0 micrograms bleomycin, the lymphocytes from the AT patient showed the highest sensitivity to this agent; our patient had an intermediate sensitivity. In both patients several rearrangements involving chromosomes 7 and 14 were scored, while none were observed in the normal subject. A colony survival assay (CSA) [Huo et al., 1994: Cancer Res 54:2544-2547], using a lymphoblastoid cell line (LCL) derived from our patient, showed a survival fraction (SF) of 7%, which is in the same range as in AT patients. The clinical picture, together with the cytogenetic and radiosensitivity results, suggests that our patient fits the variable spectrum of Nijmegen breakage syndrome.

Abnormalities, Multiple↗
PubMed1996

Effect of hydroxyurea and normal plasma on DNA synthesis in lymphocytes from Fanconi anemia patients.

Fanconi anemia (FA) is characterized at the cellular level by a high frequency of spontaneous chromosomal aberrations; crosslinking agents cause an abnormal increase in the frequency of chromosomal damage, and semiconservative DNA synthesis is severely inhibited. Deoxyribonucleotides are needed in both semiconservative and repair DNA synthesis. To investigate the involvement of deoxyribonucleotide pools in the inhibition of DNA synthesis in FA, we evaluated the effect on FA lymphocytes of hydroxyurea (HU), an inhibitor of ribonucleotide reductase which is known to alter the intracellular levels of deoxyribonucleotides. To achieve this goal, lymphocyte cultures of 4 FA patients and 4 normal individuals were used. Cultures were treated with HU and/or mitomycin C and normal human plasma. All cultures were processed to detect the number of DNA synthesizing nuclei by autoradiography. Scoring of 2000 nuclei for each kind of culture every 6 h in the last 24 h of incubation showed that, in long incubation periods, DNA synthesis in FA is largely inhibited by HU and this hypersensitivity may be partially decreased by addition of normal human plasma. It is known that recovery from damage induced by HU involves several enzymes such as flavin oxido-reductase, superoxide dismutase and catalase which are involved in the production or scavenging of O2 radicals; FA cells are deficient in the detoxification of oxygen and this could explain the response of FA cells to HU.

Cells, Cultured↗
PubMed1991

Effect of mitomycin C and bromodeoxyuridine on Fanconi anemia lymphocytes.

The authors studied the effect of mitomycin C (MMC) and bromodeoxyuridine (BrdU) on the induction of chromosome aberrations on lymphocytes of four patients with Fanconi anemia (FA) and of one normal subject. A control culture and six experiments were designed to test the possible synergic effect of MMC and BrdU. Their results revealed no evidence of MMC-BrdU synergism on the induction of chromosome aberrations in FA lymphocytes. However, chromosomes showed more damage when FA cells were harvested 24 h after MMC stress than when cells were harvested shortly after treatment. This can be explained by a DNA repair defect or by a toxic effect of oxygenation of cells during the procedure.

Bromodeoxyuridine↗
PubMed1990

Trisomy 9 mosaicism in a girl with multiple malformations.

A one-year-old girl with a mosaicism for an extra chromosome 9 is reported. Clinical findings included severe growth and mental retardation, frequent respiratory infections, peculiar face, skeletal and craniofacial abnormalities, seizures, spasticity, cardiopulmonary, gastrointestinal and genitourinary alterations. These findings were compared to those of the 10 other previously reported cases of trisomy 9 mosaicism. This helps to define the most constant phenotypical characteristics and most frequent major malformations which occur in trisomy 9 mosaicism. It is noteworthy that the reported percentage of trisomic cells was different in lymphocytes and in fibroblasts in each case.

Abnormalities, Multiple↗
PubMed1989

Pulmonary management during extracorporeal membrane oxygenation.

Traditional lung management during extracorporeal membrane oxygenation (ECMO) calls for low inspiratory and expiratory pressures with low ventilator rate to achieve lung rest. However, rapid weaning of pressures to severely injured lungs commonly leads to marked increase in pulmonary opacification as seen on chest x-ray and loss of volume. We postulated that a sufficiently high level of PEEP could prevent this deterioration. Forty-six newborns, who required ECMO therapy for refractory respiratory failure, were maintained on 8 to 14 cm H2O PEEP. The peak pressure was 20 to 24 cm H2O, rate 10 to 15 breath/min, and FIO2 0.21. Forty-one (89%) of 46 patients survived to discharge. The duration of ECMO was significantly decreased compared to the national average (82.4 +/- 43 vs. 117.5 +/- 59 h). The lungs of most patients remained adequately expanded and free of severe pulmonary opacification. Eleven of 40 patients did show significant worsening of chest x-ray compared to baseline, but only one of 18 who were on PEEP of greater than or equal to 12 cm H2O showed such deterioration. No unexpected complications were encountered. These data suggest that the use of high PEEP during ECMO safely prevents deterioration of lung function and promotes more rapid lung recovery. PEEP levels of 12 to 14 cm H2O appear to be most effective.

Extracorporeal Membrane Oxygenation↗
PubMed1988

Mitomycin C effect on Robertsonian translocations.

Centromeric breaks and dissociation of Robertsonian translocations have been suggested to be the cause of a few cases of mosaicism. One possible explanation for dissociation could be that the point of reunion of the two acrocentrics would be a structurally fragile site. Mitomycin C (MMC) treatment of lymphocyte cultures from 6 patients having a Robertsonian translocation showed that in cases 1 and 2, who were already mosaics, MMC induced a statistically significant increase of the number of cells with the dissociated translocation. In the remaining cases a preferential centromeric break on the translocation was observed, indicating instability of the region. The relationship of monocentric and dicentric translocations, the viability of the cells resulting from the dissociation, and the clinical implications are discussed.

Cell Line↗
PubMed1986

Combined high-frequency jet ventilation in a meconium aspiration model.

To evaluate the effectiveness of high-frequency jet ventilation (HFJV) in the treatment of meconium aspiration, 28 puppies were assigned randomly to one of three ventilator techniques. After aspiration of 4 ml/kg of 20% meconium and baseline measurements on conventional ventilation (CV), the animals were ventilated for 6 h with either CV, HFJV, or HFJV combined with slow conventional ventilation (combined HFJV). Arterial and mixed venous blood gases, systemic and pulmonary arterial pressures, pulmonary capillary wedge pressure, and cardiac output were measured. Combined HFJV proved superior to the other two techniques, resulting in significantly better oxygenation and ventilation at a lower mean airway pressure (Paw). Oxygenation with standard HFJV was comparable to CV, producing Paw and PCO2 values intermediate between those of CV and combined HFJV. There were no significant intergroup differences in cardiac output or the incidence of pneumothorax. Improved gas exchange was attributed to alveolar recruitment and prevention of atelectasis. Alteration of the distribution and/or clearance of meconium may also be important.

Animals↗
PubMed1980

Crossed atrioventricular connections.

Four cases of crossed atrioventricular connections are described. All of them were diagnosed at cardiac catheterization by angiocardiography and one was examined pathologically. Two possessed situs solitus, one with concordant connections and the other with discordant connections; the other had two situs inversus, both of them with concordant connections. Two had double-outlet right ventricle, one had transposition of the great arteries, and the other had normally related and connected great arteries. These cases have been interpreted as representing abnormal rotation of the ventricles following sepatation. A review of 36 cases previously reported on and our own cases, suggests that most patients have concordant atrioventricular connections. There are many types of ventriculo-arterial connections, the most frequent being transposition of the great arteries. There has not been any case reported with persistent truncus arteriosus. On the basis of atrioventriculo-arterial connections, we propose a classification for this malformation. We discuss the importance of the bulboventricular loop in the type of atrioventricular connections, some clinical implications for the diagnosis, and analyze the value of the rules to localize the ventricles by means of the position of the great arteries.

Adolescent↗
PubMed1976

[Type A Wolff-Parkinson-White syndrome associated with left bundle-branch block. Electrocardiographic, vectorcardiographic, and endocavitary electrophysiological study].

The rate association of a "type A" W.P.W. syndrome with a left bundle branch block gives a characteristic electrocardiographic picture:--the left bundle branch block is partially masked, the delay in the basial region of the left ventricle being in part cancelled by pre-excitation--the features of the W.P.W. syndrome are also modified, since the ventricular axis is corrected by the left bundle branch block. The electrocardiographic tracings taken during the various tachycardias and during treatment for arrhythmia, together with the intra-cavitary recordings allow a precise diagnosis to be made. In this case, vectocardiography was particularly useful as it gave a clear demonstration of the median delay of the ventricular loop, the only pathognomic feature of left bundle branch block, during a period when the left bundle of Kent was functioning.

Aged↗
PubMedDate not supplied

[Stroboscopic assessment of chronic laryngitis].

INTRODUCTION: The laryngostroboscopy allows analysis of the vocal fold vibrations during phonation. Disruption of normal viscoelastic properties of the superficial lamina propria results in aberrant vocal fold vibration and mucosal wave propagation. Therefore, an investigation was performed to relate the stroboscopic results with the anatomopathologic results of chronic laryngitis and glottic cancer. MATERIAL AND METHODS: We performed a retrospective study, which included 30 direct laryngoscopies with biopsy of 25 patients and their corresponding laryngostroboscopies. RESULTS: 60% of the cases of "absence of mucosal wave" displayed severe dysplasia or carcinoma. 20% of the cases of "limited or present mucosal wave" were carcinoma. CONCLUSIONS: The probability of finding severe dysplasia or carcinoma is significantly greater when we find absence of mucosal wave. The presence of mucosal wave does not exclude the possibility of malignant lesion of the vocal fold.

Adult↗
PubMedDate not supplied

[Diagnostic problems in visceral heterotaxia].

Due to the lack of uniformity in the criteria for formulating the diagnosis of the syndrome of heterotaxy, 12 cases with this abnormality were reviewed. The patients were selected on the following basis: symmetrical liver, changeable P waves in consecutive electrocardiograms, bronchial isomerism, hematological disturbances, anomalous relationship of the inferior vena cava and abdominal aorta, anomalous systemic and pulmonary venous drainage and complex cardiac malformations. The most frequent findings were: symmetrical liver, changeable P waves, anomalous systemic venous return, anomalies of the atrio-ventricular valves, particularly atrioventricular canal, aorto-cava juxtaposition, single atrium, anomalous pulmonary venous return, transposition of the great arteries and pulmonary stenosis. Less frequent anomalies were: atrial and ventricular septal defects, atrial isomerism, truncus arteriosus and partial distortion of the great arteries. The hematological disturbances as well as the radioisotope scanning of the liver and the spleen were of little help. Suggestions are given for the diagnosis of the syndrome and for the evaluation of present diagnostic procedures making necessary to use the data gathered with more precision.

Abnormalities, Multiple↗