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Biomedical subjects

A Ortega

Publications and source records attributed to A Ortega.

At least 199 records · Page 11Linked to original sources
PubMed1989

The effects of uranium on reproduction, gestation, and postnatal survival in mice.

Uranyl acetate dihydrate was tested for its effects on reproduction, gestation, and postnatal survival in Swiss mice. Four groups of animals, each of which consisted of 25 males and 25 females, were administered 0, 5, 10, and 25 mg/kg/day of uranyl acetate dihydrate. Mature male mice were treated orally for 60 days prior to mating with mature virgin female mice treated orally for 14 days prior to mating. Treatment of the females continued throughout mating, gestation, parturition, and nursing of the litters. One-half of the dams in each group were sacrificed on Day 13 of gestation and the remaining dams were allowed to deliver and wean their offspring. Postnatal development was monitored after 0, 4, and 21 days of lactation. No adverse effects on fertility were evident at the doses employed in this study. Nevertheless, embryolethality could be observed in the 25 mg/kg/day group. Significant increases in the number of dead young per litter were seen at birth and at Day 4 of lactation in the 25 mg/kg/day group. The growth of the offspring was always significantly lower for the uranium-treated animals. However, the present results suggest that uranium does not cause any adverse effects on fertility, general reproductive parameters, or offspring survival at the concentrations usually ingested by man.

Animals↗
PubMed1989

Treatment of experimental acute uranium poisoning by chelating agents.

Sixteen chelating agents were examined to determine their relative efficacy as antidotes in acute uranyl acetate intoxication in mice after subcutaneous administration. Chelators were administered intraperitoneally to male Swiss mice at a dose equal to one-fourth of their respective LD50 and the therapeutic effectiveness was calculated. Eight compounds resulted in a significant enhancement of the survival rate: Tiron, gallic acid, DTPA, p-aminosalicylic acid, sodium citrate, EDTA, 5-aminosalicylic acid and EGTA. Therapeutic indices (TI) were then determined for these chelating agents. Tiron (TI: 158), gallic acid (TI: 116) and DTPA (TI: 44.9) were the most effective antidotes. In subsequent experiments, uranyl acetate dihydrate was administered subcutaneously (10 mg/kg) in a 24 hr excretion and distribution study. The previous eight chelators were given intraperitoneally ten min. after the uranium administration. 5-Aminosalicylic acid and tiron were consistently the most effective in increasing the urinary and faecal excretion of uranium respectively. A decrease of the uranium concentration in kidneys and bone was also noted with tiron. Tiron appears to be the most effective agent of those tested in the prevention of acute uranium intoxication.

Animals↗
PubMed1989

The effects of repeated parenteral administration of chelating agents on the distribution and excretion of uranium.

The effects of repeated ip administration of gallic acid, 4,5-dihydroxy-1,3-benzenedisulfonic acid (Tiron), diethylenetriaminepentaacetic acid (DTPA), and 5-aminosalicylic acid (5-AS) on the distribution and excretion of uranium were assessed in male Swiss mice. Only Tiron significantly increased the amount of uranium excreted into urine and feces. A significant decrease in the concentration of uranium in liver, spleen and bone was observed after administration of Tiron, whereas injection of gallic acid or DTPA resulted in a significant decrease in the concentration of the metal in the liver. The results show that Tiron was consistently the most effective chelator of those tested in the treatment of uranium poisoning after repeated daily administration of the metal.

Animals↗
PubMed1988

Isolation, immunochemical characterization and localization of the kainate sub-class of glutamate receptor from chick cerebellum.

The low-affinity kainate binding sites, present at high density in chick cerebellar membranes, were solubilized with Triton X-100 and purified 41-fold. The purified kainate binding sites, therein referred to as the kainate receptor, displayed the expected pharmacological specificity: domoate = kainate much greater than L-glutamate much greater than D-glutamate, quisqualate, N-methyl-D-aspartate. Analysed by SDS-PAGE under reducing conditions, a single polypeptide with a Mr = 49,000 was observed. Western blots of membranes prepared from different brain areas and animal species were analysed using a monoclonal antibody, named mAb IX-50, raised against the purified kainate receptor. The mAb IX-50 stained the 49,000 polypeptide in chick, goldfish and mammalian brain tissues indicating its conservation during evolution. The staining intensity correlated with the density of kainate binding sites. The mAb IX-50 stained also a 93,000 polypeptide but the latter did not copurify with the 49,000 polypeptide. The kainate binding activity was selectively immunoadsorbed on mAb IX-50 coupled to Sepharose which, upon elution, released a 49,000 polypeptide. The immunohistochemical localization of mAb IX-50 binding sites in the chick cerebellar molecular layer coincided with that of the kainate receptor. We conclude that the 49,000 polypeptide is part of the kainate receptor and carries the kainate recognition site.

Animals↗
PubMed1988

Immunocytochemical and ultrastructural characterization of the cell types in the adenohypophysis of Sparus aurata L. (teleost).

The structure and immunocytochemistry of the adenohypophysis of sexually mature male specimens of Sparus aurata (gilthead sea bream) were studied. The adenohypophysis was composed of rostral pars distalis (RPD), proximal pars distalis (PPD), and pars intermedia (PI). In the RPD the prolactin cells were organized into follicles which occupied a very reduced area as corresponds to that in saltwater fishes; the corticotropic cells were surrounding the pars nervosa branches and the prolactin follicles. The PPD showed somatotropic, gonadotropic, and thyrotropic cells. The somatotropic cells were isolated, clustered, or surrounding the pars nervosa branches. Only one polymorphic cell type of gonadotropic cells was found in the PPD ventral and dorsal areas and around the PI. The PI was composed mainly of melanotropic cells and a PAS-positive cell layer adjacent to the neurohypophysis. The ultrastructure of the presumptive endocrine cells was reported and their distribution was discussed in relation to those of other teleosts.

Adrenocorticotropic Hormone↗
PubMed1988

Gliomatosis cerebri with formation of a glioblastoma multiform. Study and follow-up by magnetic resonance and computed tomography.

A case of gliomatosis cerebri studied by computed tomography (CT) and magnetic resonance imaging (MRI) is reported. Follow-up by serial CT revealed a right parieto-occipital glioblastoma. Gliomatosis cerebri and multiform glioblastoma were demonstrated by histologic study. Anatomic and CT data were correlated. The role of CT and MRI in the diagnosis of this disease was evaluated and case studies of CT published in the literature were reviewed.

Adult↗
PubMed1988

Congenital spinal cord haemangioblastoma: another cause of spinal cord section syndrome in the newborn.

A newborn infant with negative perinatal history and characteristic clinical findings of upper cervical spinal cord section is described. Metrizamide myelography performed on the 7th and 22nd days of life was negative. Peroneal somatosensory evoked responses showed a conduction block at the cervical level. Necropsy revealed a haemangioblastoma extending from levels C1 to C5.

Asphyxia Neonatorum↗
PubMed1988

Effects of administration route on pharmacokinetics of aspirin in the rabbit.

The absorption of aspirin used in the form of lysine acetylsalicylate was studied in the rabbit. Each animal received the drug by three routes: intravenous, gastric and duodenal. Plasma concentrations of acetylsalicylic acid (ASA) and salicylic acid (SA) were compared. ASA plasma concentrations obtained after gastric or duodenal administration were low compared to those after intravenous injection. Concentrations were 2 to 5 times higher after gastric than duodenal administration. SA plasma concentrations were lower at the beginning of the experiment for gastric than for duodenal administration; after 90 min the concentrations were similar. A better absorption of aspirin (as lysine acetylsalicylate) after administration occurred in the stomach than in the duodenum, but the amount of ASA which reached the central compartment was quite poor.

Animals↗
PubMed1987

Clinical usefulness of temporal artery biopsy.

To assess the diagnostic usefulness of temporal artery biopsy in temporal arteritis (TA) and establish clinical features capable of predicting its positivity we have retrospectively studied the biopsy specimens and the clinical features of 103 patients who had undergone temporal artery biopsy. Temporal artery biopsy reached a positive predictive value of 90.2% with respect to the final diagnosis based on the criteria proposed by Ellis and Ralston and the clinical course. The simultaneous presence of recent onset headache, jaw claudication, and abnormalities of the temporal arteries on physical examination had a specificity of 94.8% with respect to the histological diagnosis and of 100% with respect to final diagnosis. The presence of any of these clinical features, though of little specificity (34.4%), had a sensitivity of 100% with respect to histological diagnosis, selecting a group of patients in whom temporal artery biopsy has more discriminative value.

Adult↗
PubMed1987

Viloxazine as a betamimetic antidepressant drug.

A comparison was made between the effects of maprotiline, the sole action of which is to inhibit the reuptake of noradrenaline, of salbutamol and of viloxazine on hypothermia induced by reserpine, oxotremorine or apomorphine. The dose/effect curves in the three tests showed a similarity in profile between viloxazine and salbutamol, whereas no resemblance was evident between these two drugs and maprotiline. These facts suggest that viloxazine which has a weak effect on noradrenaline reuptake acts probably as antidepressant by betamimetic activity.

Albuterol↗
PubMed1986

Direct regulatory effect of cholesterol on the calmodulin stimulated calcium pump of cardiac sarcolemma.

A great controversy has been set for several years related to an indirect versus a direct effect of cholesterol upon the muscle calcium pump. Employing an enriched cardiac sarcolemma preparation and a (Ca2+, Mg2+)-ATPase fraction isolated from this preparation, this study demonstrates that cholesterol directly interacts with the sarcolemmal calcium pump importantly inhibiting its enzyme activity. It was discovered that this inhibition can be in part explained by a total sensitivity loss of the pump to calmodulin. These results can be considered of importance in the correlation of plasma membrane cholesterol levels with deficiencies in calcium transport and cardiac muscle cell damage.

Animals↗
PubMed1986

Use effectiveness of a spermicidal suppository containing benzalkonium chloride.

A multicentric trial in 9 Spanish Clinics of Family Planning was conducted to evaluate the effectiveness of a vaginal contraceptive Ovule (suppository), containing 18.9 mg of benzalkonium chloride. Gynaecological and cytobacteriological examinations were made to evaluate any possible side-effect. Six-hundred-fifty-three women at risk of unwanted pregnancy accepted the method as the only contraception during 9,517 months. The results are expressed in life-tables (Tietze-Lewit). Net cumulative first segment rate at 12 months were: terminations 27.2; pregnancy 3.7; medical reason 2.3; planned pregnancy 2.8; other personal reasons 18.4. At 24 months the rates were: terminations 34.1; pregnancy 3.7; medical reason 2.6; planned pregnancy 6.5; personal reasons 21.3. Error or failure to use the spermicide resulted in 12 of 23 pregnancies (52%), while in another 4 pregnancies (17%) there were reasonable elements of doubt concerning its correct use. There were no gynaecological or cytological changes. We conclude that this product is a safe and very effective contraceptive if used according to the prescribed instructions and before any sexual encounter.

Adult↗