1,721,095 research outputs found
The role of potassium and chloride ions on the Na+/acidic amino acid cotransport system in rat intestinal brush-border membrane vesicles
No full textNa-dependent D-glucose and L-alanine uptake in eel intestinal brush border membrane vesicles.
No full textHow many Na-dependent carriers for L-alanine and L-proline in the eel intestine? Studies with brush border membrane vesicles.
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Brush border inositol transport by intestines of carnivourus and herbivourus teleosts. Am. J. Physiol. 256: G501-G508.
No full textOriginal article: Steroid receptor status in malignant and non-malignant larynx
No full textWe investigated for the first time the relationships among all the different steroid receptor classes and between steroid receptor status and lymph node involvement in laryngeal carcinoma. Androgen (AR), oestrogen (ER), progesterone (PR) and glucocorticoid (GR) receptors were assayed in the high-speed soluble fraction and in the nuclear extract from 73 carcinomas of the larynx. Forty-one, 26, 15, and 13 tumours expressed cytosolic GR, ER, AR, and PR, respectively, while 33, 26, 13 and 13 biopsies were nuclear-positive for GR, ER, AR, and PR, respectively. Data obtained in histologically-proven non-cancerous larynx (N = 20) compared to those obtained in the malignant specimens showed a significant loss of ER and PR in cancerous larynx over that in the non-cancerous tissue. Lymph node metastases were evaluated in only 53 of the 73 patients and they were noted in 22 cases (41.5%). No significant relationships were found either among the different classes of steroid receptors or between steroid receptors and lymph node involvement. Despite the apparent absence of any interrelationships among the different receptors or tendency towards metastasis, the presence of steroid receptors would justify the use of hormonal manipulations which could be effective in the management of this disease
Electroneutral Na+/H+ exchange in brush-border membrane vesicles from Penaeus japonicus hepatopancreas
No full textChloride dependence of the sodium-dependent glycine transport in pig kidney cortex brush-border membrane vesicles
No full textThe Na+-dependent glycine uptake in pig kidney cortex brush-border membrane vesicles is specifically enhanced by the presence of Cl-. The Na+-independent glycine uptake is not affected by Cl-. Various anions tested could not substitute Cl- in the activation of the Na+-dependent glycine transport. Cl- is specifically required on the outer membrane side. The Na+-dependent glycine uptake is higher in the presence of an inwardly directed Cl- gradient than the one measured in the presence of equilibrated Cl-. The Na+-dependent glycine uptake depends on, and is saturable at increasing Cl- concentrations. By studying the activation of glycine uptake by Na+ in the presence and in the absence of Cl-, evidence was found that two different Na+-dependent glycine transport pathways are present in pig kidney cortex brush-border membrane vesicles. The kinetics of the glycine uptake measured in the presence of an inwardly directed NaCl gradient show the presence of two glycine transport systems, a low-affinity, high-capacity one and a high-affinity, low capacity one. In the absence of Cl- the high-affinity, low-capacity transport is almost suppressed, thus indicating the presence of a high-affinity glycine transport system simultaneously dependent on both Na+ and Cl- ions. © 1987
Human larynx expresses isoforms of the oestrogen receptor.
No full textCommercially available enzyme immunoassays (EIAs) were used for oestrogen (ER) and progesterone (PR) receptor determination in the cytosol fraction of 118 human larynx cancer specimens and in the corresponding histologically proven non-malignant tissues. Fifty-one ER positive cancerous samples had corresponding non-cancerous tissues also expressing the receptor. A high resolution isoelectric focusing (IEF) technique followed by immunoblotting with the H222 anti-ER monoclonal antibody was used to evaluate the presence of ER isoforms in the 51 ER positive human larynx cancer specimens and in their corresponding non-malignant tissues. In both tissues, four ER isoforms were detected, with isoelectric points (pI) similar to those obtained in breast and endometrium carcinomas (6.1, 6.3, 6.6 and 6.8). A significant difference in the expression of ER isoforms between cancerous and non-cancerous tissue was found; precisely, the 94.1% of the ER positive non-malignant specimens co-expressed the four isoforms while they were detected in only the 35.5% of the malignant specimens (P < 0.0001 by Fisher's exact test). In larynx cancer, the concentration values of ER and PR did not correlate, nevertheless tumours co-expressing the four ER isoforms had PR levels significantly higher than those which did not (P = 0.02 by Mann-Whitney Wilcoxon sum rank test). To investigate the possibility that the isoforms of the monomeric 4S form of the ER (those with pI 6.3, 6.6, and 6.8) could dimerise, a cold agarose gel electrophoresis technique was used on IEF-separated ER isoforms. In summary, the evidence shows that all the isoforms are able to form homodimers and that the isoforms at pI 6.3 and 6.8 are able to dimerise with that at pI 6.6 but, under the same experimental conditions, they do not form the 6.3/6.8 heterodimer. It was concluded that: (1) the four isoforms of the ER are co-expressed by the non-malignant human larynx and the cancer loses the capacity to express some of them; (2) the complete complement of ER isoforms (all four) is needed for PR expression; (3) the monomeric 4S isoform with pI 6.6 has the capacity to form homo- and heterodimers, while the remaining two are only able to homodimerise
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