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Biomedical subjects

M Haji

Publications and source records attributed to M Haji.

At least 37 records · Page 2Linked to original sources
PubMed1994

Unique change of pancreastatin-like immunoreactivity in cerebrospinal fluid by aging.

Using a specific antiserum for the C-terminal glycine amide region of human pancreastatin (PST), pancreastatin-like immunoreactivity (PST-LI) was measured in cerebrospinal fluid (CSF) from 447 subjects (368 +/- 10.8 pmol/l, mean +/- S.E.M.) free from endocrine diseases. The CSF contents of PST-LI showed a mountain-shape type change which peaked at 40 years of age. The highest concentration was found in the group of ages 40-49 years old (412 +/- 22.9 pmol/l) and the lowest concentration was found in the group of ages 80-89 years old (293.2 +/- 45.2 pmol/l) among various age groups. Gel chromatographic examination revealed the presence of two major forms (MW 13,500 and 5,400) of PST-LI in CSF. Because of the character of this antibody, the large molecular form is possibly an N-terminally elongated PST and the other may be PST-52. This may be the first report on the unique age-related change of PST concentration in CSF.

Adolescent↗
PubMed1994

Sertoli cell function declines earlier than Leydig cell function in aging Japanese men.

In order to evaluate the age-related changes in Leydig cell and Sertoli cell function, we measured serum levels of total testosterone (TT), free testosterone (FT), inhibin, LH and FSH in 116 healthy Japanese men, aged 24-92 years. Serum TT remained constant up to the age of 80 years and decreased thereafter. Serum FT declined linearly with aging and was significantly lower in men in their forties than in younger men (24-39 years old). Serum inhibin levels also declined with aging, with serum concentrations significantly lower in men older than 40 and markedly lower in men over 80 years old. LH and FSH were elevated in men over 60 and 40 years old, respectively. We also examined relationships between gonadotropins and gonadal hormones in these men divided into three age groups, young (24-39 years old), middle aged (40-59 years old) and aged (60-92 years old) men. Although there was a significant inverse correlation between LH and TT or FT for the entire population, subset analysis demonstrated that this inverse correlation was confined to men over 60 years old. In fact, in young men, TT and FT were positively correlated with LH. Overall, there was also an inverse correlation between FSH and inhibin. In subset analysis this relationship was present in both middle aged and aged men. These findings suggest that in Japanese men testicular endocrine functions decline after the fourth decade of life, and that Sertoli cell function declines earlier than Leydig cell function.

Adult↗
PubMed1994

In-vitro evidence for the regulation of 17,20-lyase activity by cytochrome b5 in adrenocortical adenomas from patients with Cushing's syndrome.

OBJECTIVE: The electron transfer system molecules, NADPH-cytochrome P450 reductase (Red) and cytochrome b5 (b5) are known to increase the relative activity of 17,20-lyase to 17 alpha-hydroxylase in vitro. Consistent with this hypothesis, we have reported recently that adrenocortical adenomas from patients with Cushing's syndrome that produced exceptionally high concentrations of androgens also contained more b5 mRNA as well as greater 17,20-lyase activity than adenomas that produced low concentrations of androgens. This finding was suggestive but inconclusive in linking b5 functionally to this difference in adenoma 17,20-lyase activity. In the present study, we have extended this finding by examining the effect of b5 on microsomal 17,20-lyase activity using an antibody against cytochrome b5. DESIGN: Biochemical quantitation of the content of b5 and Red activity in the microsomal fraction of the tumours and determination of 17,20-lyase activity in the microsomes in the presence or absence of an antibody against b5. PATIENTS: Seven patients with a clinical diagnosis of Cushing's syndrome secondary to benign adrenocortical adenoma were studied. MEASUREMENTS: The microsomal activities of 17 alpha-hydroxylase, 17,20-lyase and 3 beta-hydroxysteroid dehydrogenase were measured by in-vitro enzyme assay with thin layer chromatography. Microsomal Red activity was assayed by measuring NADPH-dependent cytochrome c reduction reaction. Cytochrome b5 concentration was determined by spectrophotometric analysis. RESULTS: An in-vitro enzyme assay of microsomal fractions from the adenoma showed that the 17,20-lyase activities of two adenomas that produced high concentrations of adrenal androgen were threefold greater than those of five other adenomas that produced low concentrations of androgens. Cytochrome b5 concentrations were greater in the two adenomas with high 17,20-lyase activity than in the other adenomas, while no significant difference in Red activity was observed among all the adenomas. The increased 17,20-lyase activity in the two adenomas was partially but significantly antagonized by an antibody against b5. CONCLUSIONS: These results suggest that differences in tissue b5 are functionally associated with differences in 17,20-lyase activity in adrenocortical adenomas in Cushing's syndrome, resulting in a dissociated secretion of cortisol and androgens in some patients.

Adenoma↗
PubMed1994

Mechanism of abnormal production of adrenal androgens in patients with adrenocortical adenomas and carcinomas.

The production of adrenal androgens can be modulated by the activities of steroidogenic enzymes and by the electron transfer system, NADPH-cytochrome P450 reductase (Red) and cytochrome b5 (b5), both of which have been shown to increase 17,20-lyase activity in vitro. To clarify the mechanism of diminished secretion of adrenal androgens in patients with adrenocortical adenoma and Cushing's syndrome and of excess secretion in patients with adrenocortical carcinoma, we investigated the enzymatic activities of cytochrome P45017 alpha, 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD), and Red as well as the content of b5 in five adenomas, three carcinomas, and two normal adrenal glands. An in vitro enzyme assay using a microsomal fraction of the tissues indicated that all the tumors had almost the same degree of 17 alpha-hydroxylase activities as the normal adrenals. However, the relative activity ratio of 17,20-lyase to 17 alpha-hydroxylase of the three adenomas was markedly diminished, and 3 beta-HSD activity was apparently lower in the three carcinomas. The messenger RNA concentrations of P45017 alpha were similar in all tumors, whereas those of 3 beta-HSD were markedly lower in the carcinomas than in other tissues. Both the content of b5 and the activity of Red were significantly lower in the adenomas. These results suggest that low concentrations of adrenal androgens in patients with adrenocortical adenomas are mainly due to low 17,20-lyase activity, which may be explained in part by a lower content of b5 and Red. In addition, high concentrations of adrenal androgens in patients with adrenocortical carcinoma are mainly due to the diminished activity of 3 beta-HSD.

3-Hydroxysteroid Dehydrogenases↗
PubMed1994

No mutation in cytochrome P450 side chain cleavage in a patient with congenital lipoid adrenal hyperplasia.

Molecular basis of lipoid adrenal hyperplasia (lipoid CAH) in a Japanese patient was investigated. A 46XY Japanese female patient was clinically diagnosed as having lipoid CAH based on her clinical history of adrenal crisis at birth and the low basal concentrations of cortisol, aldosterone, adrenal androgens and testosterone in serum. In vitro studies of testicular mitochondrial enzymes confirmed a specific impairment of cholesterol side chain cleavage (SCC) activity. However, in spite of the virtual reduction of SCC activity, the amounts of immunodetectable P450scc, adrenodoxin reductase, and adrenodoxin in testicular mitochondria were almost same as those of normal testis. Furthermore, the size of each protein was similar to that of normal testis. Enzymatic amplification of the complementary DNA encoding P450scc from the patient's testis RNA and its nucleotide analysis by direct sequencing revealed no mutation. These results indicate that defective P450scc is not the lesion in this patient, confirming a previous report showing no P450scc mutations in patients with lipoid CAH. The exact lesion causing lipoid CAH in this patient is currently unknown.

Adolescent↗
PubMed1994

Incomplete androgen insensitivity associated with a thermolabile androgen receptor.

One infant and a cousin with incomplete androgen insensitivity syndrome were reported. The familial pedigree showed that the disorder was inherited in three generations in X-linked recessive fashion. An androgen binding study of cultured genital skin fibroblast from patients showed normal maximum binding capacity and a normal apparent dissociation constant. Heat stability assay showed binding decreased to less than 30% at 41 degrees C compared with the amount at 30 degrees C, indicating that the androgen receptor was thermolabile.

Androgen-Insensitivity Syndrome↗
PubMed1994

Catechol estrogens are more potent antioxidants than estrogens for the Cu(2+)-catalyzed oxidation of low or high density lipoprotein: antioxidative effects of steroids on lipoproteins.

In order to clarify the mechanism of antiatherogenic action of several steroids such as estrogens, dehydroepiandrosterone (DHEA) and dexamethasone, we investigated the effects of various steroids on the copper (Cu2+)-catalyzed oxidation of low density lipoprotein (LDL) or high density lipoprotein (HDL) in 0.15 M NaCl by measuring thiobarbituric acid-reactive substances (TBARS). At a concentration of 10(-5) M, estrogens strongly protected against LDL oxidation by 0.5 microM Cu2+ in the following order of inhibition: estradiol (E2) (75%), estrone (E1) (35%) and estriol (E3) (30%). However, the corresponding metabolites of these estrogens, the catechol estrogens, had an even more protective effect on LDL oxidation by 0.5 microM Cu2+ in the following order of inhibition: 2-hydroxyestradiol (2-OHE2) (98%), 2-OHE1 (97%) and 2-OHE3 (96%). E2 and 2-OHE2 from 10(-7) M to 10(-5) M inhibited LDL oxidation in a dose-dependent manner, with a more marked effect for oxidation by 0.1 microM Cu2+ than by 0.5 microM Cu2+. 10(-5) M dexamethasone produced a slight (10%) but significant inhibition of LDL oxidation by 0.5 microM Cu2+. In addition, the estrogens and catechol estrogens were also effective in protecting against HDL oxidation by 0.5 microM Cu2+. Other steroids including DHEA and DHEA-sulfate had no antioxidative effects on either LDL or HDL in this system. These results indicate that estrogens and their metabolites, the catechol estrogens, exert antioxidative effects on both LDL and HDL. The catechol estrogens may be more important antioxidants than estrogens for both LDL and HDL.(ABSTRACT TRUNCATED AT 250 WORDS)

Antioxidants↗
PubMed1994

Single amino acid substitution (840Arg-->His) in the hormone-binding domain of the androgen receptor leads to incomplete androgen insensitivity syndrome associated with a thermolabile androgen receptor.

We have characterized the androgen receptor in a Japanese girl and her maternal cousin in a family with incomplete androgen insensitivity syndrome, and have investigated the molecular basis. Whole-cell androgen binding assay in cultured genital skin fibroblasts from both patients showed a normal maximum binding capacity and a normal apparent dissociation constant. However, androgen binding in fibroblasts from both patients decreased to 30% when the assay temperature was raised from 30 degrees C to 41 degrees C, indicating the presence of the thermolability of ligand binding to the androgen receptor. Sequence analysis of the coding exons of the androgen receptor gene from the patients revealed a single nucleotide substitution at position 2881 in exon G, resulting in the conversion of arginine (CGT) to histidine (CAT) at amino acid position 840 in the hormone-binding domain of the androgen receptor. The family study showed that the mothers and the maternal grandmother of the patients are heterozygous carriers for this mutation, whereas the father does not carry it, supporting the view that androgen insensitivity syndrome is an X chromosome-linked disorder. The single amino acid substitution may explain the qualitative abnormality of the androgen receptor displaying thermolability, which is thought to be the pathogenesis of incomplete androgen insensitivity syndrome in the patients.

Androgen-Insensitivity Syndrome↗
PubMed1994

Age-related increase in neuropeptide Y-like immunoreactivity in cerebrospinal fluid in women.

In order to investigate the age-related changes in neuropeptide Y (NPY) in cerebrospinal fluid (CSF) of men and women, we examined the concentration of NPY-like immunoreactivity (NPY-LI) in CSF of a large population of Japanese men and women by specific radioimmunoassay (RIA). The dilution curve of CSF extract paralleled the standard curve of RIA for human NPY. Gel chromatographic studies revealed the presence of two peaks of NPY-LI, one emerging at the elution position of synthetic NPY and another emerging at a higher-molecular-weight position. NPY-LI in the CSF in 201 men (aged 17 to 69y) and 118 women (aged 17 to 69y) was 124 +/- 4 and 136 +/- 6 pg/ml (mean +/- SE), respectively. NPY-LI in the CSF of women, but not of men, increased significantly with aging. This finding suggests that the level of NPY with aging in the central nervous system (CNS) may be regulated somewhat differently in men and women.

Adolescent↗
PubMed1994

A point mutation in the bile acid biosynthetic enzyme sterol 27-hydroxylase in a family with cerebrotendinous xanthomatosis.

Cerebrotendinous xanthomatosis (CTX) is a rare familial disorder characterized by progressive neurological dysfunction, atherosclerosis, and xanthomas with sterol storage in the nervous system, vessels, and tendons. Increased serum cholestanol, derived from intermediates of cholesterol catabolism, may possibly be a major cause of the disease. An examination was made of the cDNA encoding cytochrome P450 sterol 27-hydroxylase (CYP27) in hepatic mitochondria, considered a defective enzyme inducing CTX, in a Japanese housewife afflicted with CTX and her family. The proposita and one of her brothers, who also had CTX symptoms and hypercholestanolemia, were found to be homozygotic, carrying a point mutation in the CYP27 gene at Arg104 (CGG) to Trp104 (TGG). The mutant position has a 100% conserved positive charge in all known vertebrate cytochrome P450s and even in bacterial cytochrome P450cam. The mother of the proposita and another brother were both free of CTX symptoms and were heterozygotic for the mutation, although their plasma cholesterol increased moderately. An increase in plasma cholestanol alone would, thus, not appear to be a direct cause of sterol storage in CTX, while CTX is strongly suggested to be caused by defects in both alleles of the CYP27 gene.

Aged↗
PubMed1994

Reserved Sertoli cell function in the hypogonadic male patients with myotonic dystrophy.

To clarify the Sertoli cell and Leydig cell function in hypogonadic male patients with myotonic dystrophy (DM), serum concentrations of inhibin, total testosterone (TT), follicle-stimulating hormone (FSH) and luteinizing hormone (LH) were measured by radioimmunoassay in 6 male DM patients (41 to 56 years old, 47.7 +/- 5.05 years old) and compared with those in normal adult men. In 116 healthy men aged from 24 to 92 years, serum inhibin and TT levels decreased and serum FSH and LH concentrations increased with advancing age. There was an inverse correlation between serum inhibin and FSH. These results support the concept of negative feedback regulation system of FSH secretion by inhibin. Male DM patients showed significantly lower serum TT and higher concentrations of FSH and LH, compared with the age-matched 39 normal adult men (49-59 years old, 48.2 +/- 6.14 years old). However, there was no significant difference in serum inhibin levels between the patients and normal counterparts. These results indicate that the Sertoli cell function is reserved in male DM patient, although the Leydig cell function is impaired. It is also suggested that in these patients a negative feedback control system between inhibin and FSH may be disordered to some extent.

Adult↗
PubMed1993

Purification and characterization of a phosphoramidon-sensitive endothelin-converting enzyme in porcine aortic endothelium. OFF.

An enzyme that catalyzes the conversion of big endothelin-1 to endothelin-1, designated as endothelin-converting enzyme, was solubilized with Lubrol PX from the membrane fraction of porcine aortic endothelium and was purified by sequential chromatography on DEAE-agarose, Ricinus communis agglutinin 120-agarose, peanut agglutinin-agarose, Mono Q, and TSK G3000SWXL columns. Approximately 12,000-fold purification of the membrane fraction enzyme was achieved. The purified enzyme had a very narrow neutral pH optimum and was inhibited by EDTA, 1,10-phenanthroline, phosphoramidon, and low concentrations of some divalent cations (Cu2+,Zn2+,Co2+,Fe2+) but not by thiorphan. Addition of Zn2+ was most effective for the restoration of the EDTA-inactivated enzyme. The purified enzyme showed the highest affinity for big endothelin-1 among big endothelin isopeptides, and the Km for big endothelin-1 and the corresponding Vmax for endothelin-1 formation were 3.3 +/- 0.3 microM and 0.41 +/- 0.02 mumol/min/mg of protein, respectively. The carboxyl-terminal sequence from His27 to Gly34 and Trp21 was essential for recognition by this enzyme, while the presence of the amino-terminal loop structure reduced the hydrolysis rate. The purified enzyme showed an isoelectric point of 4.1. The molecular mass was estimated to be 131 kDa by sucrose density gradient centrifugation, and a value of 120 kDa was obtained by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, indicating that endothelin-converting enzyme is a monomeric glycoprotein.

Amino Acid Sequence↗
PubMed1993

Aromatase activity in human osteoblast-like osteosarcoma cell.

Aromatase activity was studied in cultured human osteosarcoma cell (HOS). HOS was incubated from 12 to 72 hours with 10(-10) M-10(-5) M dexamethasone. Aromatase activity was determined by measuring [3H]H2O released upon the conversion of [1 beta-3H]androstenedione to estrone. HOS showed aromatase activity, and apparent km for [1 beta-3H]androstenedione was 4.46 +/- 0.98 nm (mean +/- SD). The aromatase activity was significantly increased by 10(-9) M-10(-5) M dexamethasone in a dose-dependent manner. Dexamethasone increased Vmax of aromatase activity but did not change its km value. These results suggest that osteoblastic cells have aromatase activity which is regulated by glucocorticoid, and directly convert androgen to estrogen in itself.

Androstenedione↗
PubMed1993

A case of squamous cell lung carcinoma with high concentration of parathyroid hormone-related peptide in serum and pleural effusion presenting hypercalcemia.

A 57-year-old man with lung squamous cell carcinoma revealed hypercalcemia, hypophosphoremia, elevation of nephrogenous cAMP and metabolic alkalosis. Serum parathyroid hormone (PTH) and 1,25(OH)2D3 concentrations were not elevated. These findings were consistent with those in humoral hypercalcemia of malignancy (HHM). PTH-related peptide (PTHrP) concentrations were determined using N- and C-terminal specific radioimmunoassays (PTHrP-N, PTHrP-C), and elevation of both PTHrP-N and PTHrP-C concentrations in the serum was noted (PTHrP-N, 27 pmol/liter (normal < 5); PTHrP-C, 1408 pmol/liter (normal < 50)). High concentration of PTHrP (946 pmol/liter for PTHrP-N and 5983 pmol/liter for PTHrP-C) was also found in the pleural fluid obtained at autopsy. Immunohistochemical study, using paraffin-embedded sections of the tumor tissue obtained at autopsy, revealed numerous PTHrP-positive cells and expression of PTHrP gene was confirmed by Northern blot analysis. These findings indicate that PTHrP, produced in the tumor tissue, was secreted into the blood stream, which caused HHM in the patient. Gel permeation chromatography of the serum and pleural fluid revealed several peaks of both PTHrP-N and PTHrP-C. Molecular forms of PTHrP-N were larger than those of PTHrP-C in the serum as well as pleural fluid. These findings indicate that multiple forms of PTHrP molecules are present in the serum and pleural fluid. Granulocytosis was also noted in the patient. However, granulocyte- and granulocyte macrophage-colony stimulating factor were not detected in the serum, and the mechanism of the granulocytosis in the patient was unclear.

Blotting, Northern↗
PubMed1993

High expression of cytochrome b5 in adrenocortical adenomas from patients with Cushing's syndrome associated with high secretion of adrenal androgens.

The mechanism of dissociated secretion between adrenal androgens and cortisol observed in several clinical situations remains unclear. We investigated whether the electron transfer systems NADPH-cytochrome P450 reductase and cytochrome b5, both of which had been shown to increase 17,20-lyase activity in vitro, were involved in the reaction selectivity between 17 alpha-hydroxylase and 17,20-lyase in adrenocortical adenomas obtained from eight patients with Cushing's syndrome producing different concentrations of adrenal androgen. In vitro enzyme assay using microsomal fraction of adenoma indicated that all adenomas from seven patients showed almost the same degree of 17 alpha-hydroxylase and 3 beta-hydroxysteroid dehydrogenase (3 beta HSD) activities. However, the 17,20-lyase activities of two adenomas producing high concentrations of adrenal androgens were 3-fold greater than those of other five adenomas producing low concentrations of adrenal androgens. The mRNA concentrations of cytochrome P45017 alpha and 3 beta HSD were approximately the same in all adenomas, whereas those of cytochrome b5 in two adenomas possessing high 17,20-lyase activities were greater than those in other adenomas. The increased levels of cytochrome b5 in the two adenomas were further confirmed at the protein level using Western blot analysis of the microsomal fraction. No significant expression of NADPH-cytochrome P450 reductase was detected in any of the adenomas by Northern blot analysis. These results suggest that the difference in the concentration of cytochrome b5 in adrenal adenomas from patients with Cushing's syndrome may partially account for the difference in the amount of adrenal androgens produced by the tumors.

3-Hydroxysteroid Dehydrogenases↗
PubMed1993

A single amino acid substitution (gly743 --> val) in the steroid-binding domain of the human androgen receptor leads to Reifenstein syndrome.

The androgen receptor (AR) from a patient with Reifenstein syndrome (incomplete androgen insensitivity syndrome) was characterized. The patient's pubic skin fibroblasts had normal androgen binding. However, when incubated at 41 C, fibroblasts from the patient had a marked decrease in androgen binding as compared with normal fibroblasts. Analysis of coding sequences of the androgen receptor gene revealed a single nucleotide substitution in exon E, resulting in an amino acid change from glycine (GGG) to valine (GTG) at amino acid 743 within the steroid binding domain of AR. Reconstruction of this mutation by site-directed mutagenesis into a human AR complementary DNA followed by expression in COS1 cells led to production of a mutant AR with no significant difference in androgen binding when cells were incubated with androgen at room temperature. However, in contrast to wild type AR expressed in COS1 cells, the mutant AR had markedly lower androgen-binding affinity at 41 C. The mutant receptor could still stimulate a reporter gene at 37 C but this transcriptional stimulation was also decreased when compared with wild type AR receptor in a chloramphenicol acetyltransferase assay. These results suggest that partial androgen resistance in this patient with Reifenstein syndrome is due to a single point mutation in the steroid binding domain of the androgen receptor.

Adult↗
PubMed1993

Acromegaly with hyperprolactinemia developed after bilateral adrenalectomy in a patient with Cushing's syndrome due to adrenocortical nodular hyperplasia.

A 27-yr-old woman was referred for evaluation of acromegaly and hyperprolactinemia. She had undergone left adrenalectomy at 12 and right adrenalectomy at 17 for Cushing's syndrome due to adrenocortical nodular hyperplasia. At this time a pituitary tumor was found by brain computerized tomography, but plasma levels of growth hormone (GH), prolactin (PRL) and adrenocorticotropin (ACTH) were normal. When she was 23, symptoms and signs of acromegaly and subsequently galactorrhea-amenorrhea had developed. Plasma GH and PRL were increased and she was followed up by the administration of bromocriptine (2.5 mg-12.5 mg/day, p.o.). However the plasma GH level had been increasing gradually. On admission, plasma GH and PRL were high (19.5 micrograms/L, 61.0 micrograms/L, respectively) and increased in response to thyrotropin releasing hormone (TRH, 500 micrograms i.v.). An intrasella mass, which had been detected when she was 17, had become enlarged and was removed by Hardy's operation. Microscopically, the resected tumor was an eosinophilic adenoma. Immunohistochemical studies showed GH, PRL and ACTH positive cells localized in the tumor. Immunoultrastructural analysis of the tumor confirmed that GH, PRL and ACTH were present in secretory granules and Golgi apparatus in the tumor cells. The patient was a rare case of acromegaly with hyperprolactinemia developed after bilateral adrenalectomy of Cushing's syndrome due to adrenocortical nodular hyperplasia, all of which manifestations may be caused by a GH, PRL and ACTH secreting pituitary adenoma.

Acromegaly↗