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Biomedical subjects

M Merino

Publications and source records attributed to M Merino.

64 records · Page 4Linked to original sources

The in vivo and in vitro effects of clomiphene citrate on ovulation, fertilization, and development of cultured mouse oocytes.

Clinical data indicate a high rate of discrepancy between ovulation and pregnancy rates and a high abortion rate in anovulatory women treated with clomiphene citrate. An animal model was used to examine the in vivo and in vitro effects of the drug on fertilization and preimplantation development. This work indicates that mice treated with clomiphene in the early follicular phase of pregnant mare's serum-induced cycles show a dose-dependent decrease in ovulated oocytes. No effect was seen on the further development of these ova. When the drug was administered in the late follicular phase, a dose-dependent decrease was seen in the rate of successful copulation, ovulation, and embryo development. Concomitant 17 beta-estradiol treatment reversed the copulatory, ovulatory, and developmental effects of clomiphene. A short in vitro treatment of oocytes with clomiphene prior to in vitro fertilization resulted in an increased proportion of degenerated and unfertilized ova. Moreover, this treatment caused a dose-dependent decrease in blastocyst formation.

Animals↗

Growth requirements of Haemophilus somnus.

The growth factor needs of Haemophilus somnus, which have not been defined to date, were found to be provided by 1% IsoVitaleX (IVX; BBL Microbiology Systems) in tryptose broth. Some growth, however, occurred in unsupplemented tryptose broth. Of the ingredients of IVX, cocarboxylase was found to stimulate growth to about the same degree as the total supplement. Cocarboxylase was without direct effect in 2% peptone broth, which supported no growth of 25 H. somnus strains until supplemented with IVX, optimally at the 10% level. This could be substituted for by proportional amounts of cysteine or cystine, but by no other IVX ingredient. Cysteine-cystine and IVX but not cocarboxylase supplementation allowed H. somnus to grow in Eagle minimal medium, a completely synthetic medium, but attempts at serial passage were unsuccessful.

Culture Media↗

Catamenial pneumothorax.

Five patients with catamenial pneumothorax are reported, four of whom had proven diaphragmatic defects. Two had microscopic diaphragmatic endometrial implants in the area of the defects. No specimen was obtained in two others. A fifth patient with the condition, as well as with extensive pelvic endometriosis, was treated successfully by closed thoracostomy followed by hysterectomy and salpingo-oophorectomy. Patients with recurrent catamenial pneumothorax should be assumed to have diaphragmatic defects and be considered for treatment by thoracotomy and closure of these defects if the severity of the condition warrants it.

Adult↗

Evidence of a specialized transport mechanism for the intestinal absorption of baclofen.

Absorption of the spasmolytic drug baclofen in three selected intestinal segments of living anaesthetized rats in situ, is shown to be a specialized transport mechanism obeying Michaelis-Menten kinetics. Equation parameters were calculated through different procedures, whose features are discussed. A computer method based on the integrated form of Michaelis-Menten equation which reproduces the entire time course of drug absorption from the data found in three intestinal perfusion series at different initial concentrations, yielded Vm and Km values of 12.0 mg h-1 and 8.0 mg, respectively, in the mean segment of the small intestine, a rather selective absorption site for baclofen. Lesser but comparable absorption rates were found in the proximal and distal segments of the small intestine, whereas in colon, drug absorption was negligible. Baclofen transport was significantly reduced in the presence of the enzymatic inhibitor sodium azide. If these results were extrapolated to humans, they would explain the excellent bioavailability profiles reported for baclofen at normal doses in spite of its physicochemical properties, which do not favour passive diffusion. Based on the same principle, the administration of usual doses at shorter time intervals could be recommended, instead of high, when higher plasma levels at steady-state are needed. On the other hand, more than 8-h sustained-release preparations of baclofen should, probably, be avoided.

Animals↗

[Small fiber dysfunction in peripheral neuropathies].

INTRODUCTION: Disfunction of thin myelinated and unmyelinated fibers may appear isolated or in association with large-myelinated fibers lesion. Small-fiber neuropathy includes autonomic and sensory symptoms, most prominent of them thermo-algesic deficits. DEVELOPMENT AND CONCLUSION: In some acute neuropathies, small-fiber lesion is relatively pure, as in pandysautonomia, but it also appears in disorders with prominent somatic involvement, such as the Guillain-Barre syndrome, in which case autonomic symptoms worsens the prognosis. Small-fiber dysfunction is important in certain diseases that involve different components of the nervous system, like paraneoplastic syndromes and porphyria. Some drugs and toxic substances may damage thin myelinated and unmyelinated fibers. Nowadays, chronic idiopathic small-fiber neuropathy is diagnosed more frequently, because of the recent development of techniques that selectively evaluate this peripheral nerve component. Hereditary sensory and autonomic neuropathies can also be studied. Small-fiber dysfunction is very prominent in some diseases, e.g. diabetes mellitus and amyloidosis. In the pure autonomic failure, only the peripheral component of the autonomic nervous system is affected, and this feature is the key to make diagnosis versus multisystem atrophy. There are situations in which there is no clear deviation from normality, namely old age autonomic failure and orthostatic intolerance syndrome in which autonomic evaluation is mandatory.

Acute Disease↗

[Severe myoclonic epilepsy in infancy. Clinical and paraclinical aspects].

INTRODUCTION: Severe myoclonic epilepsy in infancy (SMEI), or Dravet s syndrome, is one of the most serious forms of epilepsy in infancy. In this study we analyse the clinical characteristics of the process. PATIENTS AND METHODS: The cases reported in the literature are surveyed, together with a personal casuistic, from both a clinical and paraclinical point of view, and we assess the form of onset and the clinical, EEG and neuroimaging manifestations at different ages. RESULTS: In most cases the disorder is characterised by onset during the first year of life, with febrile seizures, normal development prior to the onset of the seizures, multivariate critical phenomenology throughout the progression, early resistance to treatment, initial normality of EEG results and progressive neurological deterioration with ataxia and long tract signs. CONCLUSIONS: The diagnosis of SMEI depends on the combination of clinical manifestations and EEG at different ages, and the presence of myoclonic seizures constitutes the most significant fact. The lack of strict diagnostic criteria allows for the existence of cases that are not perfectly identified. A percentage of cases exist that do not fulfil all the abovementioned criteria. The recent description of a mutation in the alpha subunit of a neuronal voltage dependent sodium channel (SCN1A) in chromosome 2q24, as the likely source of the process, will allow screening to be carried out in the early phases of the disorder. It will also allow studies to be conducted on the phenotype genotype correlation of the disease.

Child, Preschool↗

Ectopic ACTH syndrome due to pheochromocytoma: case report and review of the literature.

A 51-year-old female was diagnosed preoperatively to have a pheochromocytoma producing ACTH. This diagnosis was based upon her paroxysmal hypertension, hyperpigmentation, and hypokalemia. Elevated levels of serum and urine corticosteroids, plasma ACTH, urinary VMA, and catecholamines fell after a right adrenal pheochromocytoma was removed. Subsequently this tumor was found to have a high content of ACTH. Review of the literature indicates a mortality rate of 57% for this syndrome. Proper preoperative recognition and management can result in total cure.

Adrenal Gland Neoplasms↗