Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0001430 (adenoma)
 21,222 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Enzyme activity measurements of alkaline phosphatase in surgically removed human liver tumors showed elevated level of the enzyme in 6 focal nodular hyperplasias, reduction in 8 primary hepatocellular carcinomas, and no change in the 4 adenoma samples. The activity represented liver type of alkaline phosphatase nearly in all cases because it could be inhibited by L-homoarginine more extensively than by L- phenylalanine. Studies on polyacrylamide gel electrophoresis indicated the presence of a variant type isoenzyme only in one focal nodular hyperplasia and in two hepatocellular carcinomas, one of which showed a fibrolamellar structure whereas the other was associated to cirrhosis. The importance of the elevated amount of connective tissue in the tumor, resulting in an isoenzyme shift of alkaline phosphatase, received substantial support upon comparing chemically induced rat liver tumors with and without cirrhosis.
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PMID:Alkaline phosphatase activity in human and rat liver tumors. 184 42

Several years ago the therapeutic possibilities for the treatment of inherited skin disorders were rather restricted; recently new possibilities have been developed and successfully applied. The author discusses the indications for a surgical procedure in basal cell nevus syndrome and the satisfying results revealed by dermabrasion in sebaceous adenoma of Pringle. The use of a low phenylalanine and tyrosine diet in case of palmoplantar keratosis with tyrosinemia is of theoretical as well as practical interest. However, a most striking therapeutic success is obtained by the treatment with drugs. The substitution of zinc in acrodermatitis enteropathica is very effective and not expensive! The positive effect of phenytoin in epidermolysis bullosa cicatricans is based on the partial inhibition of collagenase activity by this drug. Finally the author discusses the advantages of a treatment with retinoids in different hereditary keratinization disorders.
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PMID:[Therapeutic possibilities of hereditary diseases in dermatology]. 666 38

We have discovered two somatic mutations in the VI transmembrane domain of the thyrotropin receptor gene in thyroid hyperfunctioning adenomas. The mutated amino acid residues are phenylalanine 631 (to cysteine) and threonine 632 (to isoleucine). Cloning and expression of the mutated versions of the receptor in COS cells increased significantly the basal and the TSH-induced cAMP levels compared to the wild type receptor. Moreover, the expression of a reporter gene under the control of the cAMP-inducible promoter, was likewise constitutively activated in cells expressing the 631 and 632 TSH receptor mutants relative to the wild type. These data indicate that the VI transmembrane segment in the TSH receptor and presumably in the other G-protein coupled receptors is a critical domain for the activation of G-protein signalling and that the mutations described here may be the cause of the thyroid hyperfunctioning adenoma.
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PMID:Somatic mutations in the VI transmembrane segment of the thyrotropin receptor constitutively activate cAMP signalling in thyroid hyperfunctioning adenomas. 756 68

The synthetic hexapeptide GH-releasing peptide (GHRP; His-D-Trp-Ala-Trp-D-Phe-Lys-NH2) specifically stimulates GH secretion in humans in vivo and in animals in vitro and in vivo via a still unknown receptor and mechanism. To determine the effect of GHRP on human somatotroph cells in vitro, we stimulated cell cultures derived from 12 different human somatotroph adenomas with GHRP alone and in combination with GH-releasing hormone (GHRH), TRH, and the somatostatin analog octreotide. GH secretion of all 12 adenoma cultures could be stimulated with GHRP, whereas GHRH was active only in 6 adenoma cultures. In GHRH-responsive cell cultures, simultaneous application of GHRH and GHRP had an additive effect on GH secretion. TRH stimulated GH release in 4 of 7 adenoma cultures; in TRH-responsive cell cultures there was also an additive effect of GHRP and TRH on GH secretion. In 5 of 9 adenoma cultures investigated, octreotide inhibited basal GH secretion. In these cell cultures, GHRP-induced GH release was suppressed by octreotide. In 5 of 5 cases, the protein kinase-C inhibitor phloretin partly inhibited GHRP-stimulated GH release, but not basal GH secretion. In summary, GH secretion was stimulated by GHRP in all somatotroph adenomas investigated, indicating that its unknown receptor and signaling pathway are expressed more consistently in somatotroph adenoma cells than those for GHRH, TRH, and somatostatin. Our data give further evidence that GHRP-stimulated GH secretion is mediated by a receptor different from that for GHRH or TRH, respectively, and that protein kinase-C is involved in the signal transduction pathway. Because human somatotroph adenoma cell cultures respond differently to various neuropeptides (GHRH, TRH, somatostatin, and others), they provide a model for further investigation of the mechanism of action of GHRP-induced GH secretion.
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PMID:Growth hormone (GH)-releasing peptide stimulation of GH release from human somatotroph adenoma cells: interaction with GH-releasing hormone, thyrotropin-releasing hormone, and octreotide. 817 66

Octreotide (OCT) administration provides a biochemical cure in most acromegalic patients. This drug, however, causes several side effects and is very expensive. Acute testing has been reported to predict chronic responsiveness to OCT administration. The aim of this retrospective study was to evaluate which test, if any, among acute testing, short-term (1 month) administration, and 111In-pentetreotide (111In-DTPA-Phe-D-OCT) scintigraphy, is best in predicting response to long-term OCT treatment. Sixty-eight patients with active acromegaly were studied. An acute test (100 micrograms sc OCT) was performed as usual: a GH decrease greater than or equal to 50% of baseline was considered a positive response. GH and insulin-like growth factor I (IGF-I) were then assayed after 1 month (300 micrograms daily) and 3 months (150-600 micrograms daily) of OCT administration. GH was considered normalized when decreased less than or equal to 5 micrograms/L. Twenty-six of 68 patients were subjected to 111In-pentetreotide scintigraphy. Linear correlation analysis of the results was performed. Sensitivity, specificity, and positive and negative predictive values of the three tests were also calculated. Thirty-eight of 68 patients (56%) responded to the acute test. Among these 38 patients, 20 experienced normalization of GH and IGF-I levels during long-term therapy, as did 8 patients who did not respond to the acute test. No significant correlation was found between GH percent decrease during acute testing and long-term therapy (r = 0.11). Seven patients who responded to the acute test and 2 who did not respond had adenoma shrinkage during therapy. Conversely, GH and IGF-I decrease after short-term treatment significantly correlated with long-term treatment (r = 0.76 and 0.64, P < 0.01). Of the 26 patients subjected to 111In-pentetreotide scintigraphy, 13 had significant tracer uptake: normalization of GH and IGF-I was obtained in 8 patients. A significant correlation was found between tracer uptake and GH/IGF-I inhibition after 3 months of therapy (r = 0.6; P < 0.05). In the whole population, the positive predictive value of acute testing, short-term OCT administration, and 111In-penetreotide scintigraphy was 53%, 70%, and 73%, respectively, when the GH normalization (< 5 micrograms/L) after 3 months of therapy was considered. Moreover, 111-In-pentetreotide scintigraphy had the highest specificity (100% in patients with baseline GH values below 50 micrograms/L) compared with that of acute testing and short-term OCT administration. The acute test cannot be considered as a valuable index to identify patients' responsiveness to long-term OCT therapy, but it can be useful to test tolerability. By contrast, 1 month of OCT administration or the in vivo imaging of somatostatin receptors by 111-In-pentetreotide might better indicate the patients who might effectively benefit from this treatment.
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PMID:Prediction of efficacy of octreotide therapy in patients with acromegaly. 896 77

Endothelin-1 (ET-1) receptors of normal adrenal gland (ADR, 6 cases), aldosterone-producing adenoma (APA, 5 cases), idiopathic hyperaldosteronism (IHA, 4 cases) and pheochromocytoma (PHE, 6 cases) in human were measured by radioligand binding assay (RBA) of receptors. Binding studies using 125I-ET-1 as a radio ligand showed the presence of a single class of high-affinity binding sites for ET-1 in all of the above tissues. The values of dissociation constant (Kd) of ET-1 for its receptor were similar in ADR, APA and IHA (28.3 +/- 2.5, 27.9 +/- 6.1, 27.7 +/- 1.9 pmol/L, respectively), but the maximal binding capacity (Bmax) of ET receptor tended to be lower in APA tissue (107.2 +/- 13.2 fmol/mg protein) in comparison with ADR (P < 0.01) and IHA (P < 0.05, 274.9 +/- 40.8, 247.0 +/- 19.8 fmol/mg protein, respectively). Both the Kd (50.8 +/- 5.1 pmol/L) and Bmax (675.3 +/- 93.7 fmol/mg protein) in PHE were higher than those in ADR (P < 0.01), APA (P < 0.01) or IHA (P < 0.05 for Kd, P < 0.01 for Bmax). Our data may suggest that there is the down-regulation for ET-1 receptor in APA and support the concept of an important role of ET-1 in the paracrine-autocrine regulation of aldosterone and catecholamine secretion in the adrenal and adrenal tumors.
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PMID:[Endothelin-1 receptors of the normal adrenal gland and adrenal tumors in human]. 959 18

The biosynthesis of met-enkephalin in human pituitary and human pituitary adenomas is still not well known. In this work, we studied the processing of proenkephalin-derived peptides in postmortem human pituitary (PMHP), ACTH-producing adenomas (ACTH-PA), nonfunctioning adenomas (NFA), and GH-producing adenomas (GH-PA). ACTH-PA contained at least 10 times more proenkephalin-derived peptides than PMHP, NFA,and GH-PA. Proenkephalin processing was different in the four tested tissues. In ACTH-PA, proenkephalin was processed to high-, intermediate-, and low-mol-wt products. The highest met-enkephalin-containing peptides levels corresponded to intermediate and low-mol-wt materials, although met-enkephalinArg-Phe and synenkephalin immunoreactivity appeared only in high-mol-wt peptides. In PMHP and NFA, met-enkephalin-Arg-Phe immunoreactivity was detected in intermediate- and low-mol-wt materials, and it was absent in GH-PA. Immunoblotting of ACTH-PA showed that met-enkephalin-Arg-Phe immunoreactivity corresponded to peptides of 44, 32-30, 27, and 17 kDa. The 32-30 and 17-kDa molecules were localized in the nuclear fraction where they were extracted after enzymatic digestion with DNase I. Plasmatic met-enkephalin levels did not increase in patients with Cushing's disease, suggesting that the pentapeptide stored in ACTH-PA was not released to the general circulation. In conclusion, we demonstrated that only ACTH-PA contained high levels of proenkephalin peptides, which were stored in cytoplasm organelles and in the nucleus, probably bound to chromatin. These results suggest an adenoma-specific physiological role of proenkephalin products.
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PMID:Elevated proenkephalin-derived peptide levels in ACTH-producing adenomas: nucleus and cytoplasm localization. 974 27

Familial hyperparathyroidism (HPT), characterized by hypercalcemia and hypercalciuria, and familial benign hypocalciuric hypercalcemia (FHH) are the most common causes of hereditary hypercalcemia. The calcium-sensing receptor (CaR) regulates PTH secretion and renal calcium excretion. Heterozygous inactivating mutations of the gene cause FHH, whereas CaR gene mutations have not been demonstrated in HPT. In a kindred with 20 affected individuals, the hypercalcemic disorder segregated with inappropriately higher serum PTH and magnesium levels and urinary calcium levels than in unaffected members. Subtotal parathyroidectomy revealed parathyroid gland hyperplasia/adenoma and corrected the biochemical signs of the disorder in seven of nine individuals. Linkage analysis mapped the condition to markers flanking the CaR gene on chromosome 3q. Sequence analysis revealed a mutation changing phenylalanine to leucine at codon 881 of the CaR gene, representing the first identified point mutation located within the cytoplasmic tail of the CaR. A construct of the mutant receptor (F881L) was expressed in human embryonic kidney cells (HEK 293), and demonstrated a right-shifted dose-response relationship between the extracellular and intracellular calcium concentrations. The hypercalcemic disorder of the present family is caused by an inactivating point mutation in the cytoplasmic tail of the CaR and displays clinical characteristics atypical of FHH and primary HPT.
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PMID:Familial hypercalcemia and hypercalciuria caused by a novel mutation in the cytoplasmic tail of the calcium receptor. 1084 46

Intestinal electroneutral NaCl absorption is mediated by parallel operation of Na(+)/H(+) and Cl(-)/HCO(3)(-) exchange in the enterocyte apical membrane. The ion transporters involved are Na(+)/H(+) exchanger 3 (NHE3) and the down regulated in adenoma (dra) gene product. cAMP-mediated inhibition of NHE3 requires the transporter to bind to the second PDZ (PSD95, disk large, ZO1) domain of the adapter protein NHE3 kinase A regulatory protein (E3KARP). Because the C-terminal four amino acids of dra are ETKF (glutamate-threonine-lysine-phenylalanine), resembling a PDZ interaction motif, we hypothesized that dra may also bind to one of the PDZ domains of E3KARP. In vitro the ETKF motif of dra binds to the second PDZ domain of E3KARP, the affinity being comparable to that of the known ligand CFTR. The C-terminal phenylalanine, which is an unconventional residue in PDZ interaction motifs, can only be substituted by the classical residue leucine, but not by other hydrophobic residues (valine, isoleucine). Immunofluorescence colocalizes dra, NHE3, and E3KARP in the apical compartment of human proximal colon. We suggest a model in which both NHE3 and dra bind to the second PDZ domain of E3KARP and that linking of the transporters occurs through dimerization of E3KARP. In such a model, the first PDZ domain would remain available for instance for signal transduction proteins.
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PMID:The down regulated in adenoma (dra) gene product binds to the second PDZ domain of the NHE3 kinase A regulatory protein (E3KARP), potentially linking intestinal Cl-/HCO3- exchange to Na+/H+ exchange. 1236 22

Ochratoxin A is a naturally occurring fungal toxin that is a contaminant in corn, peanuts, storage grains, cottonseed, meats, dried fish, and nuts. Toxicology and carcinogenesis studies were conducted by administering ochratoxin A (98% pure) in corn oil by gavage to groups of F344/N rats of each sex for 16 days, 13 weeks, 9 months, 15 months, or 2 years. Only rats were studied because ochratoxin A has been shown to be carcinogenic in mice. Genetic toxicology tests were performed with bacterial and mammalian cells. Urinalysis, hematologic and serum chemical analyses, and bone marrow cellularity determinations were conducted at 9, 15, and 24 months in the 2-year studies. Sixteen-Day and Thirteen-Week Studies: Rats were administered 0, 1, 4, or 16 mg/kg ochratoxin A in corn oil by gavage 5 days per week for a total of 12 doses over 16 days. All rats that received 16 mg/kg ochratoxin A died within 6 days. Rats that received 4 mg/kg lost weight. Compound-related lesions in rats included bone marrow hyperplasia, thymic atrophy, necrosis and hyperplasia of the forestomach epithelium, renal tubular cell degenerative and regenerative changes (nephropathy), and adrenal gland hemorrhage. Renal tubular changes were most severe in animals that received 4 mg/kg. Rats that received 16 mg/kg had less severe renal lesions than those at 4 mg/kg, perhaps because the acute toxicity and early death did not allow sufficient time for full development of lesions. No compound-related deaths occurred in the 13-week studies (doses were 0 and 0.0625 to 1 mg/kg). The final mean body weight of rats that received 0.25, 0.5, or 1 mg/kg was 7%, 11%, or 19% lower than that of vehicle controls for males and 3%, 4%, or 9% lower for females. Compound-related lesions in the kidney were characterized as degeneration and regeneration of the epithelium of the proximal convoluted tubules with individual cell necrosis of moderate severity (see page 3 of the Technical Report). Karyomegaly of tubular epithelial cells was widespread but most pronounced in the straight portion of the tubules just above the corticomedullary junction. Karyomegaly was present in all dosed groups, and the severity increased as the dose increased. At lower doses, atrophy of the straight portions of the tubules at the corticomedullary junction and in the medulla was observed. Based on mortality and on the presence and severity of renal lesions, groups of 80 rats per sex and dose group were administered 0, 21, 70, or 210 ug/kg ochratoxin A in corn oil by gavage 5 days per week for up to 2 years. Groups of 15 rats per sex and dose were killed at 9 or at 15 months and the remaining animals at 2 years. Nine-Month and Fifteen-Month Studies: Administration of ochratoxin A by gavage for 9 months or 15 months to F344/N rats was associated with increased incidences of renal tubular cell neoplasms in males and hyperplasia, degeneration, and karyomegaly of renal tubular epithelial cells in both males and females (see page 4 of the Technical Report). Body Weight and Survival in the Two-Year Studies: Mean body weights of high dose rats were generally 4%-7% lower than those of vehicle controls. No significant differences in survival were observed between any groups of female rats (vehicle control, 32/50; low dose, 23/51; mid dose, 35/50; high dose, 34/50). Survival was decreased after 77 weeks in high dose male rats and after 96 weeks in low and mid dose male rats (39/50; 26/51; 26/51; 23/50). Clinical Pathology: Minor differences were observed for hematologic values between dosed and vehicle control animals, but these were not considered to be of biologic significance. Results of serum chemistry analysis were not clearly compound related. Ochratoxin A-dosed animals had slight increases compared with vehicle controls in urine volume and decreases in urine specific gravity in concentration tests, suggesting that exposure resulted in mild to moderate decreases in the ability to concentrate urine. Nonneoplastic and Neoplastic Effects in the Two-Year Studies: A spectrum of degenerative and proliferative cho-Year Studies: A spectrum of degenerative and proliferative changes occurred in the kidney of male and female rats given ochratoxin A for 2 years. Degeneration of the renal tubular epithelium with formation of tubular cysts, proliferation of the tubular epithelium, and karyomegaly of the nuclei of tubular epithelial cells occurred at increased incidences in dosed rats (see page 5 of the Technical Report). Hyperplasia of the renal tubular epithelium and renal tubular adenomas and carcinomas also occurred at increased incidences in the dosed rats; the tumors were frequently multiple within a single kidney or were bilateral, and many metastasized to other organs. The incidence of fibroadenomas of the mammary gland in high dose female rats was significantly greater than that in vehicle controls (vehicle control, 17/50; low dose, 23/51; mid dose, 22/50; high dose, 28/50). Multiple fibroadenomas of the mammary gland were observed at an increased incidence in high dose female rats (4/50; 4/51; 5/50; 14/50). One mammary gland adenoma was seen in a mid dose female, and two mammary gland adenocarcinomas were seen in each dosed group; one adenocarcinoma was seen in the vehicle control group. An adenoma of the pars intermedia of the pituitary gland was observed in one mid dose female rat, and a carcinoma was observed in a second mid dose female rat. Squamous cell papillomas of the tongue were seen in two low dose and two mid dose male rats. Neither the pituitary neoplasms nor the papillomas of the tongue were considered related to ochratoxin A exposure. Genetic Toxicology: Ochratoxin A was not mutagenic in four strains of Salmonella typhimurium (TA97, TA98, TA100, or TA1535) when tested both with and without exogenous metabolic activation. In cultured Chinese hamster ovary (CHO) cells, ochratoxin A induced sister chromatid exchanges (SCEs) in the presence, but not the absence, of metabolic activation; it did not significantly increase the number of chromosomal aberrations in these cells. Audit: The data, documents, and pathology materials from the 2-year studies of ochratoxin A have been audited. The audit findings show that the conduct of the studies is documented adequately and support the data and results given in this Technical Report. Conclusions: Under the conditions of these 2-year gavage studies, there was clear evidence of carcinogenic activity of ochratoxin A for male F344/N rats as shown by substantially increased incidences of uncommon tubular cell adenomas and of tubular cell carcinomas of the kidney. There was clear evidence of carcinogenic activity for female F344/N rats shown by increased incidences of uncommon tubular cell adenomas and of tubular cell carcinomas of the kidney and by increased incidences and multiplicity of fibroadenomas of the mammary gland. Ochratoxin A administration also caused nonneoplastic renal changes including tubular cell hyperplasia, tubular cell proliferation, cytoplasmic alteration, karyomegaly, and degeneration of the renal tubular epithelium. Synonym: (R)-N-[(5-chloro-3,4-dihydro-8-hydroxy-3-methyl-1-oxo-1H-2-enzopyran-7-yl)-carbonyl](-L-)phenylalanine
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PMID:Toxicology and Carcinogenesis Studies of Ochratoxin A (CAS No. 303-47-9) in F344/N Rats (Gavage Studies). 1269 83


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