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Biomedical subjects

M Molina

Publications and source records attributed to M Molina.

At least 181 records · Page 10Linked to original sources
PubMed1981

[Influence of the superior laryngeal and recurrent nerves on several reflex respiratory responses (author's transl)].

Respiratory effects determined by mechanical stimulation of several areas on the upper respiratory airways epithelium have been studied in cat. Influences of superior laryngeal and recurrent nerves were also observed. Air flow larynx resistance changes have been recorded by means of glottis in situ and isolated technique. Mechanical stimulation of tracheal epithelium showed a cough response with a larynx resistance decrease. The same response was obtained by electrical stimulation of the central end of the recurrent nerve. Bilateral section of those nerves produced a larynx resistance decrease which brought out the predominance of a constrictor tone in the larynx intrinsic muscles maintained by recurrent efferent fibres. Mechanical stimulation of subglottal epithelium was characterized by apnea followed by cough, glottis closures and again expiratory apnea. Bilateral section of superior laryngeal nerves suppressed the above response, otherwise obtained by electrical stimulation of the central end. Mechanical stimulation of supraglottal epithelium was characterized by glottis closures and occasional coughing. Bilateral section of superior laryngeal nerves did not alter this effect.

Animals↗
PubMed1980

Absence of arsenite mutagenicity in E coli and Chinese hamster cells.

Because exposure to compounds of arsenic has been implicated as a cause of cancer, an investigation of the mutagenicity of sodium aresenite in E coli and in Chinese hamster cells was performed. In the E coli system, Trp + revertants were not induced by arsenite in a variety of experimental protocols including spot tests, treat and plate protocols, and fluctuation tests. The mutator effect of a tif-1 strain was partially blocked by arsenite. Arsenite did not cause the induction of lambda prophage. In Chinese hamster cells, arsenite did not induce ouabain-resistant mutants or thioguanine-resistant mutants. We conclude that arsenite is not mutagenic to E coli or to Chinese hamster cells. When added to the plating medium, arsenite can act as an anti-mutagen by inhibition of induction of the error-prone SOS repair system in E coli.

Animals↗
PubMed1979

[Vagal control of larynx resistance to the air flow (author's transl)].

Air flow larynx resistance changes have been recorded in dogs after electrical stimulation and lesion of the recurrent and vagus cervicalis nerves respectively. Experiments were carried out with glottis in situ and isolated. The effects of the administration of athropine i.v. (0.3 mg/kg) were also studied. Air flow larynx resistance decreased after secting the right recurrent nerves as well as after athropine administration. Electrical stimulation of the central end of the right vagus nerve produced a complex response characterized by an initial apnaea followed by a larynx resistance decrease. After a few seconds the response continued with glottis spasms followed by typical emetic movements. During the emetic movements larynx closed and opened throughout the respiratory cycle, the closing movement being simultaneous with the inspiratory position of the thorax and with minimal values of the intraabdominal pressure. Larynx resistance increased after uni- and bilateral sections of the vagus cervicalis and after the electrical stimulation of the peripheral end of the right vagus cervicalis. According to the present results, the possible existence of a controlling reflex of laryngeal sphincter motility, generated at the bronchopulmonary level, is postulated.

Airway Resistance↗
PubMed1978

[Long-arm deletion of chromosome 1: 46,XY, del (1) (Q42) (author's transl)].

A case of long-arm deletion of chromosome No. 1: 46,XY, del (1) (q42) is reported. From the revised bibliography only two cases are comparable cytogenetically, not so phenotypically. The usefulness of the recent banding techniques in the precise diagnosis of small structural anomalies of the chromosome is outlined and the difficulty in establishing the relationship between chromosomal alteration and phenotypical characters are commented.

Child, Preschool↗
PubMed1978

[Larynx resistance produced by upper respiratory airways stimulation (author's transl)].

Larynx resistance changes during the respiratory cycle at rest and after mechanical stimulation of the epithelium on different zones of the upper airways (extrathoracic trachea, glottis, nasopharynx) were studied in the dog by isolated glottis in situ technique. In reposed breathing, the increase in larynx resistance always started when inspiratory airflow reached its maximum value. Resistance remained high during expiration and had its lowest value when expiratory airflow decreased towards zero. The electromyogram reading for the abdominal muscle evinced low or no activity during the smaller larynx resistance period. The extrathoracic trachea mechanical stimulation with cough response was determined by a significant decrease of larynx resistance. There was also a significant increase in expiratory airflow and abdominal pressure. Inspiratory and expiratory total lung resistance values were both significantly increased with regard to reposed breathing. Mechanical larynx stimulation determined reflexive closing of the glottis, expiratory apnea, minimal abdominal pressure. No potentials were formed in the expiratory abdominal electromyogram. The response was similar to a spontaneous swallowing. Larynx resistance reached its minimal value before the expiratory airflow reached zero. Mechanical nasopharyngeal stimulation significantly increased larynx resistance.

Airway Resistance↗
PubMed1978

[Bronchopulmonary influences in larynx resistance (author's transl)].

Larynx resistance changes have been studied in the dog by means of in situ isolated glottis technique. Bronchiolar tone changed through isoprenaline and histamine administration, and after recurrent and vagus nerve bilateral section. Isoprenaline administration (0.1 mg/kg) was followed by larynx resistance decrease, expiratory duration increase, and expiratory abdominal pressure decrease with regard to respiration preceded by rest. Cough response by mechanical tracheal stimulation and glottis closing by larynx stimulation were abolished after isoprenaline administration. Histamine administration (0.1 mg/kg) was followed by larynx resistance increase, expiratory duration decrease, expiratory abdominal pressure increase, and expiratory abdominal pressure/maximum expiratory airflow relation increase. Larynx resistance decreased after recurrent nerve bilateral section, and increased later when vagus nerves were sectioned.

Airway Resistance↗
PubMed1977

[Gonadotropin reserve in anorexia nervosa].

Four patients with anorexia nervosa were studied. All patients in the acute stage of the illness had low serum luteinizing hormone (LH) levels which were unresponsive to clomiphene. The four women showed almost no LH response on a single iv injection of 100 mug LH-RH; however, the FSH response was similar to that of normal eumenorrheic women. When the patients had regained weight the LH levels were normal, and they responded normally to LH-RH. These results seem to suggest that impaired hypothalamic function is the cause of gonadotropin deficiency in most patients with anorexia nervosa.

Anorexia Nervosa↗
PubMedDate not supplied

Native polyacrylamide gel electrophoresis of membrane proteins: glutaminase detection after in situ specific activity staining.

A new procedure for the analysis and detection of phosphate-activated glutaminase (EC 3.5.1.2) by native electrophoresis has been developed. The method is based on the in situ detection of glutaminase activity in two different systems of native polyacrylamide gradient gels, containing 3-(3-cholamidopropyl)-dimethyl-ammonio-1-propane sulfonate (CHAPS) or Triton X-100 as nondenaturant detergents. Crude Triton X-100 extracts of mitochondria were resolved by electrophoresis. The enzyme was specifically revealed by incubation of the gel with glutamine and coupling the oxidation of the glutamate formed to the reduction of a tetrazolium dye, in the presence of glutamate dehydrogenase trapped in a 1% agar solid overlay. Both Ehrlich ascitic cell and mouse kidney glutaminases were resolved by native electrophoresis and specifically detected with the activity staining. Moreover, the redox-cycling staining was tested in solution, showing linearity with the amount of glutamate or glutaminase activity present. The method described could be a useful tool for native polyacrylamide gel electrophoresis of membrane proteins.

Animals↗
PubMedDate not supplied

Complex regulation of nucleoside transporter expression in epithelial and immune system cells.

Nucleoside transporters have a variety of functions in the cell, such as the provision of substrates for nucleic acid synthesis and the modulation of purine receptors by determining agonist availability. They also transport a wide range of nucleoside-derived antiviral and anticancer drugs. Most mammalian cells co-express several nucleoside transporter isoforms at the plasma membrane, which are differentially regulated. This paper reviews studies on nucleoside transporter regulation, which has been extensively characterized in the laboratory in several model systems: the hepatocyte, an epithelial cell type, and immune system cells, in particular B cells, which are non-polarized and highly specialized. The hepatocyte co-expresses at least two Na+-dependent nucleoside transporters, CNT1 and CNT2, which are up-regulated during cell proliferation but may undergo selective loss in certain experimental models of hepatocarcinomas. This feature is consistent with evidence that CNT expression also depends on the differentiation status of the hepatocyte. Moreover, substrate availability also modulates CNT expression in epithelial cells, as reported for hepatocytes and jejunum epithelia from rats fed nucleotide-deprived diets. In human B cell lines, CNT and ENT transporters are co-expressed but differentially regulated after B cell activation triggered by cytokines or phorbol esters, as described for murine bone marrow macrophages induced either to activate or to proliferate. The complex regulation of the expression and activity of nucleoside transporters hints at their relevance in cell physiology.

Animals↗
PubMedDate not supplied

Biochemical and histopathological findings after a long-term intraperitoneal fat infusion. An experimental study in rats.

The object of this work was to see the possible side effects that a long-term intraperitoneal (IP) fat infusion would have. We used 56 female Wistar rats weighing 250 g, divided into a control group (CG) of eight and three groups of 16 in each one. These three groups were administered a 20% Intralipid infusion in a daily amount of 4 g/kg over 5, 10, and 15 days, respectively (groups I, II, and III) intraperitoneally. Twenty-four hr after the last infusion the animals were anesthetized and after having drawn 3 ml of blood, 5% glutaraldehyde (GTH) was instilled in situ and optical and electron microscopic specimens were taken of the lung, liver, right diaphragm, and parietal peritoneum. The results show a decrease in triglyceride (TG) rate 24 hr after the last infusion in each group, but blood glucose, cholesterol, bilirubin, glucose oxidase test (GOT), glutamic pyruvic transaminase (GPT), nor other serum parameters varied. No alterations were noticed in the lung or liver under optical or electron microscopes in the groups than had under gone treatment, except for an increase in circulating macrophages with fat in the lung. In the diaphragm we observed hyperplasia in the serous layer of the peritoneum and an increase in fat in the lymphatic channels of the right diaphragm. The possibility of using IP infusions in order to study parenteral nutrition solutions was put forward as well as their possible clinical use in alternative nutrition techniques on both a short-term and long-term basis.

Animals↗