Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C1519176 (PSA)
 5,490 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Rats were exposed to an acute dose of lead (Pb) to study the effect of Pb intoxication on different sialoglycoconjugates in serum, brain and liver. Serum levels of total sialic acid (TSA), perchloric acid (PCA)-soluble sialic acid (PSA), lipid-bound sialic acid (LBSA), free sialic acid (FSA) and alpha 1-acid glycoprotein (alpha 1-AG) were determined. They were also estimated in brain and liver tissues, except for LBSA and FSA. All these constituents were found to be significantly raised in the serum but not in the brain. In the case of the liver, only alpha 1-AG levels were found to be increased significantly, the rest were not altered. The levels of these sialoglycoconjugates in serum might be useful as biomarkers of heavy metal toxicity.
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PMID:Effect of lead on the blood serum, liver and brain sialoglycoconjugate levels in rats. 134 25

PSA is a 34-kd 240-amino acid glycoprotein produced by the prostatic epithelial cells. It is a member of the glandular kallikrein gene family and has a high sequence homology with human glandular kallikrein (hGK-1). PSA is a serine protease and has chymotrypsin-, trypsin-, and esterase-like activities. It is secreted into the seminal fluid where it degrades two seminal vesicle proteins that are important components of the semen coagulum, thus playing an important role in semen liquefaction. The production of PSA protein appears to be under the control of circulating androgens acting through the androgen receptor. Therefore, the significance of a low serum PSA value in a patient who has undergone previous antiandrogen therapy may not be the same as that for a patient who has not received endocrine treatment.
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PMID:Prostate-specific antigen and prostatic acid phosphatase: biomolecular and physiologic characteristics. 171 6

Tear samples were collected from 46 healthy volunteers evenly distributed according to sex and age (mean age 43.5 years). Samples were denatured in a Tris-HCl sample buffer containing 2-mercaptoethanol and SDS, and applied to a gradient SDS-polyacrylamide gel for electrophoresis. The proteinaceous material was transferred to nitrocellulose by a semi-dry blotting technique, and the glycoprotein content subsequently visualized by incubation with four lectins (WGA, PHA, PSA and SBA) and staining with avidin horseradish-peroxidase. Glycoprotein bands were generally found to be significantly less frequent in persons under the age of 30 years. Apart from this the technique gave a uniform picture of the glycoprotein profile, with only modest differences according to age and/or sex. The technique may therefore be suitable for the detection of differences in the glycoprotein composition indicative of disease.
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PMID:The normal human tear glycoprotein profile detected with lectin probes. 193 80

Sixty-six human lung neoplasms of different histological types and normal bronchial epithelial cells of newborn babies and adults were studied histochemically using ConA and PSA and the result was compared with that of CEA. Normal mucosal epithelium could bind to ConA, and the location of ConA receptors was related to the maturation of mucosal epithelial cells. Normal mucosal epithelium in adult bronchi failed to be stained with PSA and anti-CEA, and most of lung neoplasms could bind to PSA and positive for CEA, indicating that new glycoconjugate and CEA-glycoprotein could be synthesized after malignant transformation of mucosal epithelium. The binding of ConA, PSA and anti-CEA to cell membrane and nucleus membrane was characteristic of squamous cell lung cancer while lung adenocarcinoma mainly showed cytoplasmic staining. The weak staining of ConA, PSA and anti-CEA in small cell carcinoma and negative staining in carcinoid and malignant melanoma help testify that their origin may differ from that of squamous cell carcinoma and adenocarcinoma.
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PMID:[Histochemical localization of glyco-conjugate and CEA-glycoprotein in human lung neoplasms]. 224 89

Three new potential biomarkers--PAC, PMA, and the 7E11-C5 glycoprotein--have been identified. All three have unique features that could augment current diagnostic and therapeutic modalities. Some of the important characteristics of these potential markers are summarized in Table 1. Further studies will be required to determine if any of them will provide clinical information beyond that provided by PSA and if they will have a significant impact on the management of patients with prostate cancer. The MAb 7E11-C5 (CYT-356), now in clinical trials, promises to offer new strategies for radioimmunodetection and radioimmunotherapy of prostate cancer.
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PMID:Biomolecular and clinical characteristics of PSA and other candidate prostate tumor markers. 750 67

PSA is a 34-kDa 240-amino-acid glycoprotein produced exclusively by prostatic epithelial cells. PSA is a serine protease, is a member of the kallikrein gene family, and has a high sequence homology with human glandular kallikrein. It has chymotrypsin-, trypsin-, and esterase-like activities. In the serum it is present mainly in a complex form with alpha 1-antichymotrypsin. It is secreted in the seminal plasma and is responsible for liquefaction of the seminal coagulum. The production of PSA proteins appears to be under the control of circulating androgens acting through the androgen receptors. The PSA gene is up-regulated predominantly by androgens at both the protein and mRNA levels. DRE causes minimal changes in the PSA level, while prostate massage, ultrasonography, systoscopic examination, and prostate biopsy can all cause clinically significant elevations. Other conditions, such as prostatitis, prostate intraepithelial neoplasia, acute urinary retention, and renal failure can also elevate the PSA level. The value of PSA as a screening tool is questionable because of the great deal of overlap in PSA levels between BPH and prostate cancer. However, if used in men over 50, in conjunction with DRE and/or ultrasonography, it may become a vital part of the early detection program. PSA's role in determining the clinical and pathological stage is also limited, in spite of the direct correlation between the pathological stage and the PSA level, because of great overlap in the PSA levels in various stages. The most important clinical utility of PSA is in monitoring patients after definitive therapy. PSA is most sensitive and reliable in the detection of a residual tumor, possibly recurrence, or disease progression following treatment, irrespective of the treatment modality. PSA can accurately predict the tumor status and can detect recurrence several months before its detection by any other method. PSA is also a very sensitive and specific immunohistochemical marker for tumors of prostatic origin. Compared to PAP, PSA is a more precise and meaningful marker in all clinical situations. With the development of ultrasensitive assays and the adoption of an international standard PSA calibrator, so that results from multicenter studies can be compared, PSA could become one of the most useful tumor marker in cancer biology.
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PMID:Prostatic specific antigen. 753 74

Without question, much has been learned about the glycoprotein PSA in recent years. By increasing our understanding of this tumor marker's biochemical and physiologic properties, we will be able to improve its clinical utility. The discovery of the various molecular forms of PSA represents a significant advancement. Knowing the concentration and ratio of these PSA forms will be valuable in deciding which patients require further evaluation with transrectal ultrasound and prostate biopsy and which men can be monitored safely without undergoing further invasive testing. This information will be most valuable in treating the patient with a mildly elevated serum PSA level. Although assays are not yet available to detect specifically hK2, the striking similarities of hK2 to PSA, including selective expression in the prostate, suggest that this marker may also prove useful in prostate cancer management. Indeed, a new era of PSA testing has been entered, and the entire field of prostate cancer will benefit.
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PMID:Molecular forms of prostate-specific antigen and the human kallikrein gene family: a new era. 753 36

Human prostate specific antigen, PSA, is a product of the human glandular kallikrein gene locus on chromosome 19 that is almost selectively expressed by prostate tissue. PSA is one of the dominating prostate derived proteins in seminal fluid. The mature form of PSA, a single chain glycoprotein of 237 amino acids, is a serine protease manifesting restricted chymotrypsin-like activity. PSA is mainly responsible for gel dissolution in freshly ejaculated semen by proteolysis of the major gel forming proteins, semenogelin I and II, and fibronectin. In semen approximately two thirds of PSA is enzymatically active. The remaining 30-40% is inactive due to internal cleavage(s). A few per cent of PSA in semen is complexed to the protein C inhibitor. PSA complexed to alpha 1-antichymotrypsin (ACT) constitutes the predominant molecular form of serum PSA, although complex formation is slow between the purified proteins in vitro. PSA also forms stable complexes with alpha 2-macroglobulin in vitro but as this results in encapsulation of PSA and complete loss of the PSA-epitopes, the in vivo significance of this complex formation is presently unclear. A free, non-complexed form of PSA constitutes a minor fraction of the serum PSA despite the large molar excess of antiproteasees such as ACT. In patients with carcinoma of the prostate the serum PSA level increases. Analysis of the serum level of PSA is used both for diagnosing and monitoring patients with carcinoma of the prostate (CAP).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Biochemistry of prostate specific antigen, PSA. 754 81

Puberty in primates is triggered by a gonad-independent reinitiation of a pulsatile mode of GnRH release. The purpose of the present study was to begin to examine the hypothesis that this neuroendocrine event is the result of structural or plastic changes within the neural network governing the activity of GnRH neurons. Specifically, we sought to determine whether polysialic acid neural cell adhesion molecule (PSA-NCAM), a plasma membrane-associated glycoprotein that has previously been proposed to be a marker for postnatal neuronal plasticity, was expressed within GnRH neuron containing areas of the rhesus monkey hypothalamus. The study employed male monkeys that were castrated prepubertally. Immunocytochemistry of hypothalamic tissue from four animals of pubertal age employing a monoclonal antibody (12F8) specific for PSA-NCAM revealed the presence of PSA-NCAM immunoreactivity within the region of the arcuate nucleus and median eminence of the medial basal hypothalamus (MBH) and in the region of the organum vasculosum of the lamina terminalis of the rostral hypothalamus, two areas in the monkey brain where GnRH neurons are concentrated. As expected, immunostaining for total NCAM using a polyclonal rabbit antibody to mouse total NCAM was uniformly distributed throughout hypothalamic sections containing the MBH. Double staining showed that some, though not all, GnRH cell bodies of the MBH were located within the PSA-NCAM-immunopositive region of the arcuate nucleus and the median eminence. The pattern of PSA-NCAM immunoreactivity in the MBH of three prepubertal monkeys was similar to that seen for the older animals. Western analysis of a membrane extract from the MBH of a monkey of pubertal age, employing antibody 12F8, identified a broad band of staining at the expected molecular weight for this adhesion molecule. A similar, but less intense, immunoreactive band was observed for the preoptic area. In contrast, an immunoblot of a membrane extract of cerebral cortex was only faintly positive for PSA-NCAM. Taken together, the foregoing findings are consistent with the notion that structural changes within the MBH may underlie the pubertal reinitiation of pulsatile GnRH release. Moreover, the presence of PSA-NCAM in the MBH of prepubertal monkeys suggests that the role, if any, of this molecule in the onset of sexual maturation in primates is permissive in nature.
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PMID:Postnatal expression of polysialic acid-neural cell adhesion molecule in the hypothalamus of the male rhesus monkey (Macaca mulatta). 769 45

The adult hypothalamo-neurohypophysial system, responsible for the secretion of the neurohormones, oxytocin, and vasopressin, undergoes reversible neuronal-glial and synaptic changes in response to stimulation (parturition, lactation, and osmotic stimulation). In the hypothalamus, these changes result in reduced astrocytic coverage of oxytocinergic somata and dendrites and concomitant increases in their GABAergic synapses; in the neurohypophysis, they lead to an enlarged neurovascular contact area. We discuss the possible role played by certain cell adhesion molecules, such as the highly sialylated isoform of the neural cell adhesion molecule, PSA-NCAM, the F3 glycoprotein, and the extracellular matrix molecule, tenascin, in such plasticity. The hypothalamo-neurohypophysial system continues to express high levels of these molecules during adulthood and they may serve as permissive factors to allow stimulus-induced structural remodelling to occur.
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PMID:Adhesion molecules and structural plasticity of the adult hypothalamo-neurohypophysial system. 793 46


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