Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.3.1 (alkaline phosphatase)
 47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We determined the effect of nucleotides and protein kinase A (PKA) on the Ca(2+)-dependent gating of the cloned intermediate conductance, Ca(2+)-dependent K(+) channel, hIK1. In Xenopus oocytes, during two-electrode voltage-clamp, forskolin plus isobutylmethylxanthine induced a Ca(2+)-dependent increase in hIK1 activity. In excised inside-out patches, addition of ATP induced a Ca(2+)-dependent increase in hIK1 activity (NP(o)). In contrast, neither nonhydrolyzable (AMP-PNP, AMP-PCP) nor hydrolyzable ATP analogs (GTP, CTP, UTP, and ITP) activated hIK1. The ATP-dependent activation of hIK1 required Mg(2+) and was reversed by either exogenous alkaline phosphatase or the PKA inhibitor PKI(5-24). The Ca(2+) dependence of hIK1 activation was best fit with a stimulatory constant (K(s)) of 350 nM and a Hill coefficient (n) of 2.3. ATP increased NP(o) at [Ca(2+)] >100 nM while having no effect on K(s) or n. Mutation of the single PKA consensus phosphorylation site at serine 334 to alanine (S334A) had no effect on the PKA-dependent activation during either two-electrode voltage-clamp or in excised inside-out patches. When expressed in HEK293 cells, ATP activated hIK1 in a Mg(2+)-dependent fashion, being reversed by alkaline phosphatase. Neither PKI(5-24) nor CaMKII(281-309) or PKC(19-31) affected the ATP-dependent activation. Northern blot analysis revealed hIK1 expression in the T84 colonic cell line. Endogenous hIK1 was activated by ATP in a Mg(2+)- and PKI(5-24)-dependent fashion and was reversed by alkaline phosphatase, whereas CaMKII(281-309) and PKC(19-31) had no effect on the ATP-dependent activation. The Ca(2+)-dependent activation (K(s) and n) was unaffected by ATP. In conclusion, hIK1 is activated by a membrane delimited PKA when endogenously expressed. Although the oocyte expression system recapitulates this regulation, expression in HEK293 cells does not. The effect of PKA on hIK1 gating is Ca(2+)-dependent and occurs via an increase in NP(o) without an effect on either Ca(2+) affinity or apparent cooperativity.
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PMID:Kinase-dependent regulation of the intermediate conductance, calcium-dependent potassium channel, hIK1. 1061 55

In order to investigate the clinical characteristics of hematological abnormality in patients with systemic lupus erythematosus (SLE) and inquire into the basis for differential diagnosis, the hematological data of 92 cases with lupus erythematosus-related hematological disorder (SLERHD) were retrospectively analyzed by use of SPSS/PC software. The results showed that these patients were short of specificity in clinical manifestation and hemogram, however, all cases possessed multiple SLE-related autoantibodies, increase of serum globulin level and varying extent dermal and arthral signs. The incidence of primary or initial symptom in the 92 cases was as follow: 65 anemia (72.8%), 39 purpura (42.4%), 17 hemolytic anemia (18.5%), 56 leukopenia (60.9%), 54 thrombocytopenia (58.7%), and 41 pancytopenia (44.6%). The bone marrow examinations showed that the cellularity of nucleated cells was mostly normal, and active proliferation in 57 cases (61.9%) and hypercellularity in 35 cases (38.1%); the G/E ratio was normal in majority, and G/E ratio > 3 in 59 cases (64.1%) and < 3 in 33 cases (35.9%) and G/E < 1 in 17 cases with hemolytic anemia Coombs' test positive; megakaryocyte counts were normal in 11 cases (11.9%), increase in 80 cases (86.9%) and lower than 7/marrow smear in 1 case (1.1%). Neutrophil alkaline phosphatase staining was negative in all of the cases. From above data it is concluded that patients with SLERHD are varied in clinical and blood pictures, but all patients are provided with multiple SLE-related autoantibodies, globulinemia and dermal and arthral signs. It is easy to identify SLERHD from aplastic anemia, myelodysplastic syndrome, idiopathic thrombocytopenic purpura, autoimmune hemolytic anemia and Evans' syndrome by comprehensive and detailed clinical and laboratory examinations.
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PMID:[Clinical features of hematological abnormality in systemic lupus erythematosus-related hematological disorders]. 1251 74

We report a case of primary biliary cirrhosis (PBC)-autoimmune hepatitis (AIH) overlap syndrome with concurrent idiopathic thrombocytopenic purpura (ITP) and Hashimoto's disease with positivity for anticentromere antibody. The patient was a 64-year-old woman with symptoms of jaundice and general fatigue. About 30 years earlier, she had been diagnosed as having ITP and had undergone splenectomy. As part of her present history, she had exhibited liver dysfunction in 1995, during the follow-up of Hashimoto's disease, and a liver biopsy led to the diagnosis of PBC. In March 2000, she was admitted to hospital because of general fatigue and jaundice. Blood tests revealed: total protein (TP), 6.6 g/dl; gamma-globulin (glb), 35.9%; total bilirubin (T-bil), 9.41 mg/dl; direct bilirubin (D-bil), 7.52 mg/dl; aspartate aminotransferase (AST), 957 U/l; alanine aminotransferase (ALT), 651 U/l; alkaline phosphatase (ALP), 595 U/l; gamma-guanosine triphosphate (GTP), 129 U/l; IgG, 2620 mg/dl; IgM, 223 mg/dl; hepatitis B surface antigen (HBsAg), negative; anti-hepatitis C virus (HCV), negative; antinuclear antibody, positive; antimitchondrial antibody (AMA), negative (by the immunofluorescence [IF] method); and anti-pyruvate dehydrogenase complex (PDC)-E2 antibody, positive (by Western blotting). Anticentromere antibody (ACA), which is an alternative diagnostic marker for PBC, was detected in this patient. Prednisolone was administered after admission and liver function test results improved markedly. The liver biopsy in 1995 had revealed infiltration of lymphocytes and plasma cells in the portal areas with fibrous expansion and periportal necrosis. Destructive cholangitis was observed, as well as scattered epitheloid cell granulomas in some portal areas. Liver biopsy after the steroid treatment revealed alleviated necrotic inflammatory responses of hepatocytes, while the destructive cholangitis persisted. This is a very rare case of PBC-AIH overlap syndrome accompanied by ITP and Hashimoto's disease which provides a possible insight into the mechanisms and interplay of autoimmune diseases.
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PMID:PBC-AIH overlap syndrome with concomitant ITP and Hashimoto's disease with positivity for anti-centromere antibody. 1517 50

Corticosteroids have been widely used in the treatment of idiopathic thrombocytopenic purpura (ITP). We evaluated the late side effects of high-dose methylprednisolone (HDMP) therapy on bone metabolism in children with ITP. Twenty-eight children with acute ITP treated with HDMP (30 mg/kg/d for 3 d then 20 mg/kg/d for 4 d) and 28 controls were enrolled in the study. Bone mineral density (BMD), urinary calcium creatinine ratio, urinary levels of deoxypyridinoline, serum levels of calcium, phosphate, parathyroid hormone, total alkaline phosphatase, and bone-specific alkaline phosphatase were measured in both groups. Magnetic resonance imaging of the femoral head was performed only in study group. The mean levels of serum phosphate, parathyroid hormone, urinary deoxypyridinoline, and calcium creatinine ratio were significantly increased in the study group. There was no significant difference between the 2 groups in terms of serum calcium, total alkaline phosphatase, bone-specific alkaline phosphatase, and BMD values. There was a statistically significant negative correlation between cumulative steroid dose and BMD values in study group (r = -0.379). Osteonecrosis was observed in 3 of 25 patients by magnetic resonance imaging. In conclusion, HDMP therapy, especially in high cumulative doses, increases the bone resorption and may cause osteonecrosis in children with ITP.
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PMID:Late side effects of high-dose steroid therapy on skeletal system in children with idiopathic thrombocytopenic purpura. 1901 72


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