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C Morales

Publications and source records attributed to C Morales.

At least 163 records · Page 9Linked to original sources
PubMed1990

A procedure for enrichment and isolation of mutants of the salt-tolerant yeast Debaryomyces hansenii having altered glycerol metabolism.

The salt-tolerant yeast Debaryomyces hansenii produces and accumulates glycerol when subjected to salt stress, whereby the buoyant density of the cells is changed. This property allows for enrichment of mutants with altered glycerol metabolism by density gradient centrifugation. Colonies derived from cells with rapidly changing density following an osmotic shock were screened for increased glycerol production by observing their ability to support growth of a glycerol-requiring strain of Escherichia coli. The glycerol overproducting phenotype of two isolates was confirmed by chemical analysis.

Centrifugation, Density Gradient↗
PubMed1990

Osmoregulation of the salt-tolerant yeast Debaryomyces hansenii grown in a chemostat at different salinities.

The intracellular solute composition of the salt-tolerant yeast Debaryomyces hansenii was studied in glucose-limited chemostat cultures at different concentrations of NaCl (4 mM, 0.68 M, and 1.35 M). A strong positive correlation between the total intracellular polyol concentration (glycerol and arabinitol) and medium salinity was demonstrated. The intracellular polyol concentration was sufficient to balance about 75% of the osmotic pressure of the medium in cultures with 0.68 and 1.35 M NaCl. The intracellular concentration of K+ and Na+, which at low external salinity gave a considerable contribution to the intracellular water potential, was only slightly enhanced with raised medium salinity. However, the ratio of intracellular K+ to Na+ decreased; but this decrease was less drastic in the cells than in the surrounding medium, i.e., the cells were able to select for K+ in favor of Na+. The turgor pressure, which was estimated on the basis of intracellular solute concentrations, was 2,200 kPa in cultures with 4 mM NaCl and decreased when the external salinity was raised, resulting in a value of about 500 kPa in cultures with 1.35 M NaCl. The maintenance of a positive turgor pressure at high salinity was mainly due to an increased production and accumulation of glycerol.

Glucose↗
PubMed1990

[Clinical significance of cervical arthropathy in patients with vertigo].

We performed a thorough neuro-otological evaluation and a radiological study of the cervical spine in 102 patients with vestibular symptoms. A group of 20 asymptomatic subjects served as control. Some degree of cervical spondylosis was found in 121 of 122 patients but also in the majority of control subjects. No relationship was observed between the degree of cervical spondylosis and vestibular abnormalities. Instead, the latter were strongly related to age. Thus, an age dependent microvascular damage may be more likely as an etiological factor for vestibular symptoms in the elderly.

Age Factors↗
PubMed1989

Sulfated glycoprotein-1 (saposin precursor) in the reproductive tract of the male rat.

Sulfated glycoprotein-1 is one of the major protein secretion products of rat Sertoli cells in culture. This 70,000 Mr protein shares substantial sequence similarity with human prosaposin, the precursor of lysosomal saposins. Saposins are known to enhance the activity of lipid modifying enzymes presumably by solubilizing the lipids. We report here the immunolocalization of sulfated glycoprotein-1 in the cells and fluid of the male reproductive tract. The protein is present in secondary lysosomes of Sertoli cells and also in the luminal fluid of seminiferous tubules and epididymis. The highest concentrations of the protein are in seminiferous tubule fluid and rete testis fluid, while relatively low amounts are found in cauda epididymal fluid and serum. Sulfated glycoprotein-1 is believed to be involved in degradation of lipids in residual bodies and may also assist in modification of membrane lipids during sperm maturation.

Animals↗
PubMed1989

Anaphylaxis produced by rubber glove contact. Case reports and immunological identification of the antigens involved.

A study was carried out on six subjects suffering from anaphylactic reactions including asthma, rhinoconjunctivitis, contact urticaria and hypotension following contact with rubber gloves. All of them showed skin sensitivity and serum specific IgE to various preparations of natural latex, and not to other chemicals used in glove manufacturing. Immunoblotting techniques demonstrated that at least four soluble polypeptides from natural latex had the ability to bind specific human IgE. The results suggested that natural latex proteins present in rubber gloves can cause severe specific hypersensitivity reactions.

Adolescent↗
PubMed1989

Function of vitamin A in normal and synchronized seminiferous tubules.

Vitamin A is clearly an important factor in spermatogenesis. Some of the new data on metabolism of retinoids in the testis has contributed to our understanding of the mechanism(s) involved in the action of vitamin A. It is probable that the requirement of the testis of vitamin A deficient rats for retinol but not retinoic acid involves access of the retinoids to various testicular compartments. Retinol may be required by germinal cells because of a requirement for esterification in order to be successfully transported by the Sertoli cells. Existing evidence suggests that both the Sertoli cells and the germinal cells have specific requirements for retinoids. In the vitamin A deficient rat there appears to be a developmental block at preleptotene spermatocyte and type Al spermatogonia stages. This block is removed by retinol and germinal cell development reinitiates in a synchronous manner. The synchronous testis model offers a number of advantages for the study of molecular events associated with the cycle of the seminiferous epithelium and the development of germinal cells as well as for investigations into the mechanism of action of the retinoids.

Amino Acid Sequence↗
PubMed1989

T-zone histiocytes and recurrence of papillary urothelial bladder carcinoma.

We have studied the histologic distribution and prognostic significance of T-zone histiocytes (TZH) in 89 papillary urothelial bladder carcinomas (PUC), 3 cases of nonspecific cystitis (NC) and 4 cases of follicular cystitis (FC) by immunohistochemical determination of S-100 protein. Nineteen (21.37%) of the PUC cases have been found to have TZH S-100-positive with a variable density intratumor, along the papillary axis, or in the lymphoid aggregates of the vesical wall. All four FC cases were also TZH-positive, with a distribution and density similar to those of follicular dendritic cells of lymph nodes, although none of the 3 NC cases presented TZH. The recurrence-free period was significantly (p less than 0.05) longer in TZH-positive patients.

Carcinoma, Transitional Cell↗
PubMed1988

Detection of Candida sp. mannan antigen by indirect ELISA-inhibition. In vitro crossed reactivity among mannans obtained from C. albicans A, C. albicans B, and C. tropicalis.

We have obtained mannans from four Candida species: C. albicans A, C. albicans B and C. tropicalis; anti-mannan sera against C. albicans A, C. albicans B and C. tropicalis were obtained by immunizing rabbits subcutaneously with the respective yeast extract. The efficacy of these sera in reacting with mannans obtained from three Candida sp. has been proven by indirect ELISA-inhibition. Any of three immune sera can be used to detect mannan antigen from the three Candida sp. tested. This confirms the existence of crossed reactivity and the possibility of detecting mannan antigen in serum from patients infected by different Candida sp., although we had only one immune serum and one Candida mannan.

Animals↗
PubMed1988

Molecular biology of the Sertoli cell.

The "nurse cell" concept developed as a result of the morphological relationships between germ cells and Sertoli cells, and because of the junctional barrier defined by Sertoli cells which allowed the creation of a compartment in which the constituents could be regulated by Sertoli cells. The molecular approach to studies of the role of Sertoli cells in spermatogenesis has already led to a better understanding of the "nurse cell" concept. Molecular studies on the function of Sertoli cells have for the most part been dependent on the Sertoli cell culture techniques which were first published in 1975 (Dorrington and Fritz 1972; Steinberger et al. 1975a; Welsh and Wiebe 1975). As a result of this technical innovation Sertoli cells which remained responsive to hormones and which continued to carry on secretory activities could be obtained relatively free of other cell types. In the spent medium from cultured Sertoli cells specific secretion products could be detected such as ABP, transferrin, and SGP-2; components with inhibin-like activity; and metabolic products such as lactate. Thus, for the first time some molecular correlates to the "nurse cell" role of Sertoli cells have been described. In addition to the close morphological relationships between germ cells and Sertoli cells it has now been demonstrated that protein products of the Sertoli cells directly interact with germ cells. The Sertoli cell-mediated iron transport to germ cells via transferrin is the clearest demonstration of this interaction. Both SGP-1 and SGP-2 interact with spermatozoa and can be found tightly associated with the plasma membrane of these cells. As more of the secretion products of Sertoli cells are characterized the important role of these cells in spermatogenesis and spermiogenesis will be underscored. The identification and characterization of the Sertoli cell secretion products is important information to obtain, but an understanding of the function of these products also requires temporal knowledge about their synthesis. The interdependence of the morphological observations of the testis and the new technology of molecular biology is most clearly illustrated by the studies involving quantitative in situ hybridization. This technique has been utilized to quantify the amount of transferrin and SGP-2 mRNA present in Sertoli cells associated with different stages of the cycle of the seminiferous epithelium and to establish positively the Sertoli cell location of a specific mRNA (Morales et al. 1987). The technique is potentially applicable to any Sertoli cell specific protein product for which a cDNA probe becomes available.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1987

Stage-dependent levels of specific mRNA transcripts in Sertoli cells.

Localization and stage-dependent levels of transferrin and sulfated glycoprotein-2 (SGP-2) mRNAs were examined in rat testes by in situ and soluble hybridization of mRNA with a single-stranded RNA probe prepared with the SP65 vector. Biotinylated RNA probes were identified in testicular tissue by using a biotinylated glucose oxidase-avidin system followed by a treatment with an appropriate electron carrier and a tetrazolium salt. This procedure demonstrated that the anatomical site of transferrin and SGP-2 gene expression was the Sertoli cells. Tritium-labeled RNA probes were visualized by radioautography. Negative and positive controls as well as in situ hybridization in Sertoli and myoid cells in culture indicated again that the cytoplasm of Sertoli cells was the anatomical site of transferrin and SGP-2 expression. Quantitative radioautography revealed cyclic variations in the level of both transferrin and SGP-2 mRNAs. The level of transferrin mRNA was relatively high from Stage I to Stage VIII. At Stage IX, the level decreased acutely and remained low in Stage X. The level of transcripts increased dramatically at Stage XIII, remaining high until Stage XIV. In the case of SGP-2 mRNAs, levels of transcripts were similar in most stages except at Stages VII and VIII, where higher levels were observed. These data were substantiated by similar results obtained by solution hybridization of both recombinant cRNAs with mRNAs from selected seminiferous tubules staged by transillumination. Thus, our results demonstrated a stage-specific regulation of transferrin and SGP-2 mRNA levels in Sertoli cells.

Animals↗
PubMed1987

Transport of iron and transferrin synthesis by the seminiferous epithelium of the rat in vivo.

The transport of radioactive iron across the seminiferous tubules was analyzed in vivo by light-microscope quantitative radioautography. At 5 min after a single intratesticular injection of 55Fe-transferrin, a strong labeling of the basal aspect of the seminiferous epithelium was observed. Between 30 min and 2 h, the labeling on the basal aspect of the seminiferous epithelium decreased. This decrease was accompanied by a substantial increase of the radioautographic reaction over the cellular elements in the adluminal compartment. These results were consistent with the demonstration of 59Fe associated with meiotic spermatocytes and differentiating spermatids isolated by velocity sedimentation from testes injected with 59Fe-transferrin. Furthermore, after a single intratesticular injection of 59Fe-labeled human transferrin, radiolabeled rat transferrin was immunoprecipitated from homogenates of isolated tubules with a specific antibody and appeared as a single radioactive band on fluorographs of urea/polyacrylamide gels. Similarly, 59Fe-labeled rat transferrin but not 125I-transferrin was immunoprecipitated from rete testis fluids of testes infused with either 59Fe- or 125I-labeled human transferrin. Finally, the synthesis of testicular transferrin in vivo was demonstrated in fluorographs of immunoprecipitated transferrin after an intratesticular injection of 35S-methionine in rats whose livers were excluded from the general circulation by ligation of both the hepatic artery and the portal vein. Thus, our results demonstrated a unidirectional system of iron transport from the basal compartment of the seminiferous epithelium to the germ cells in the adluminal compartment involving two distinct transferrins, i.e., a serum transferrin and a testicular transferrin synthesized by the seminiferous epithelium.

Animals↗
PubMed1987

Retinol-induced stage synchronization in seminiferous tubules of the rat.

Vitamin A deficiency (VAD) in rats causes a progressive germ cell depletion and cessation of spermatogenesis resulting in seminiferous tubules which contain only Sertoli cells, spermatogonia and a small number of preleptotene spermatocytes. Spermatogenesis can be rapidly restored by the administration of retinol. Our preliminary studies suggested a partial stage synchronization of many seminiferous tubules in VAD male rats subsequently treated with retinol. To confirm this observation and to achieve a better synchronization, VAD rats received 2 SC injections of retinol suspended in sesame oil followed by daily oral administrations of 0.5 mg of retinol. In all rats an almost perfect synchronous stage development of seminiferous tubules evolved in a predictable manner and was maintained through 2 spermiations.

Animals↗
PubMed1987

Malignant and atypical meningiomas: a reappraisal of clinical, histological, and computed tomographic features.

A series of 21 patients with atypical and malignant meningiomas is presented. Histological criteria such as high cellularity, typical and atypical mitosis, necrosis, infiltration of the underlying brain, poor differentiation, and distant metastasis define nonbenign meningiomas. Male predominance in this nonbenign group is significant when compared to a group of 205 benign meningiomas, which were also operated on. The malignant and atypical meningiomas are compared with the benign meningiomas, and special emphasis is placed on their computed tomographic features. The presence of tumor fringes (suggesting invasion of the brain substance) and intratumoral hypodense areas were both significant signs of malignancy of atypia. Radical surgical excision is still considered the treatment of choice.

Adolescent↗
PubMed1987

[Kinetin and the germinating capacity of Lupinus multilupa seeds].

The effect of kinetin (10(-6) M and 10(-4) M) on the germinating capacity and incorporation of 8-C14 adenine into DNA, RNA and RNA Poly A+ of embryos and cotyledons from Lupinus multilupa L. seeds have been studied. Kinetin enhanced the germinative capacity of the seeds and the incorporation of 8-C14 adenine into DNA, RNA and Poly A+ of embryos and cotyledons. However, there seems to be no close relationship between the DNA and RNA biosynthesis of embryos and cotyledons and the ability of the seeds to germinate and their embryos to continue growing.

DNA↗