Adverse event profiles of hypomagnesemia caused by proton pump inhibitors using the Japanese Adverse Drug Event Report (JADER) Database.

Proton pump inhibitors (PPIs) are commonly used for the prevention or treatment of gastric ulcers, but they can induce hypomagnesemia. Little is known about the onset duration and risk factors related to patient characteristics of this adverse event in Japanese patients. Therefore, we analyzed the time-to-onset of PPI-induced hypomagnesemia and evaluated the association between hypomagnesemia and PPIs using the Japanese Adverse Drug Event Report (JADER) database. We analyzed hypomagnesemia cases between 2004 and 2021. The time-to-onset analysis was performed using the Weibull distribution, and the adjusted reporting odds ratio (aROR) or 95% confidence interval (95% CI) was calculated using a multiple logistic regression analysis. The analysis database comprised 236,525 cases, with 188 cases associated with hypomagnesemia. The median onset duration (interquartile range) of PPI-induced hypomagnesemia was 99.0 (51.8-285.5 ) days, which is considered the random failure type. The multiple logistic regression analysis revealed that hypomagnesemia is significantly associated with male sex (aROR, 95% CI: 1.66, 1.23-2.25) , age < 60 (1.59, 1.14-2.21) , estimated body-mass index (eBMI) (0.94, 0.91-0.98) , PPIs (1.66, 1.18-2.30) , and the interaction of age (<60)*PPIs (1.58, 1.13-2.19) . However, diuretics were not significantly associated with hypomagnesemia. Our results suggest that serum magnesium levels should be measured regularly regardless of the duration of PPI use, especially in patients with male sex, age < 60, or low BMI. These findings will assist health professionals in the adequate use of PPIs. These findings need to be evaluated by cohort studies and long-term clinical investigations.

Time-dependent changes in serum magnesium levels in patients receiving cetuximab with low baseline serum sodium levels.

Cetuximab causes electrolyte abnormalities, such as hypomagnesemia, hypokalemia, and hypocalcemia. However, little is known about the relationships between the onset of hypomagnesemia, patient background before administration, and time-dependent changes in serum magnesium levels. Therefore, we examined the patient backgrounds that influenced the onset of hypomagnesemia and the time-dependent changes in serum magnesium levels in patients receiving cetuximab. A retrospective study was performed to investigate patients with advanced or recurrent colorectal cancer or head and neck cancer, treated with a cetuximab regimen from 2012 to 2020 at Kindai University Nara Hospital. In total, 52 patients who met the inclusion criteria were enrolled in this study. The serum magnesium level was significantly lower in the hyponatremia before the administration group than in the non-hyponatremia group (p < 0.001). Univariate logistic regression analysis revealed that the baseline serum sodium levels (odds ratio [OR]: 0.741, 95% confidence interval [CI]: 0.588-0.934) and the combination of magnesium oxide tablet (OR: 0.997, 95% CI: 0.995-0.999) were one of the independent factors for hypomagnesemia. These results indicated that hyponatremia before administration may be an indicator of serum magnesium levels after administration of cetuximab. Cetuximab-induced hypomagnesemia may be predicted using baseline serum sodium levels, and hypomagnesemia may be prevented by administration of magnesium oxide tablets. Our findings provided new evidence for the management of serum magnesium levels in patients receiving cetuximab.

Phenotypic modulation of smooth muscle cells in lymphoedema.

BACKGROUND: Lymphoedema is a debilitating progressive condition that is frequently observed following cancer surgery and severely restricts quality of life. Although it is known that lymphatic dysfunction and obstruction underlie lymphoedema, the pathogenic mechanism is poorly understood. Smooth muscle cells (SMCs) play pivotal roles in the pathogenesis of various vascular diseases, including atherosclerosis. OBJECTIVES: We analysed SMCs in lymphatic vessels from the lymphoedematous legs of 29 patients. METHODS: Expression of smooth muscle α-actin (SMαA) and smooth muscle myosin heavy chain (SM-MHC) isoforms SM1 and SM2 was investigated using immunohistochemistry. RESULTS: Compared with normal lymphatic vessels, all affected lymphatic vessels in chronic lymphoedema showed marked wall thickening. In addition to increases in the numbers of rows of SMαA(+) SM1(+) SMCs in the tunica media, SMCs were also observed in the subendothelial region (tunica intima). While most intimal and medial cells were positive for SMαA and SM1, staining for SM1 and particularly SM2, a marker of mature SMCs, progressively declined in lymphatic vessels in increasingly severe lymphoedema lesions. Consequently, the SM1(+) and SM2(+) cell fractions were significantly reduced in the tunica media and intima of lymphatic vessels. CONCLUSIONS: These observations indicate that the lymphatic tunica media and tunica intima consist mainly of phenotypically modulated SMCs, and that SMCs play a key role in the development of lymphoedema.

CD56-Positive cutaneous lymphoma with multicentric Castleman's disease-like systemic manifestations.

We report a 55-year-old Japanese male with CD56+ cutaneous lymphoma. The patient had multiple cervical lymphadenopathy, a red nodule on his neck, and parotid gland nodularity. Histologic features of the biopsied cervical lymph node showed follicular hyperplasia with numerous plasma cells. A biopsied skin specimen of the nodule on his neck demonstrated dense infiltration of atypical large lymphocytes into the dermis. Immunohistochemical study of this specimen revealed CD3+, CD4+, and CD56+ expression in the majority of neoplastic cells. Polymerase chain reaction assays for the detection of Epstein-Barr virus sequences were positive for lymph node and skin DNA. Laboratory examinations showed polyclonal gammopathy, pancytopenia, and high serum interleukin-6 levels. These clinical and histological findings resembled those of multicentric Castleman's disease.

Sclerotic fibroma of tendon sheath.

Two cases of sclerotic fibromas directly related to the tendon sheath are presented. Fibroma in these 2 cases consisted of hypocellular, homogeneous collagen bundles that were closely related to the subjacent tendon sheath, and were described by the term 'sclerotic fibroma of tendon sheath'. It is possible that the sclerotic fibroma may arise from fibroma of tendon sheath and that common pathomechanisms exist between these two types of fibroma.

Characterization of rat monoamine oxidase A with noncovalently-bound FAD expressed in yeast cells.

The FAD-binding cysteine of rat liver monoamine oxidase A (MAO A), Cys406, was converted to an alanine by site-directed mutagenesis of the cDNA. The wild-type and mutated enzymes were expressed in yeast cells and catalytic activities were assayed, using as substrates serotonin, tyramine, and kynuramine. Specific activities of the Ala-mutant for these substrates, calculated as the activities per pargyline-sensitive molecule, were about half of those of the wild-type enzyme. The Km values of the mutant enzyme for the substrates were similar to those of the wild-type enzyme. An adduct between FAD and pargyline, a mechanism-based inhibitor, was attached to the apoprotein in the wild-type enzyme, while in the Ala-mutant it was detached from the apoprotein, thereby indicating the presence of noncovalently bound FAD in the mutant enzyme. The Ala-mutant rapidly lost activity during incubation, whereas the wild-type enzyme retained the initial activity. Partial protection from inactivation occurred in the presence of FAD, but not of FMN. Recovery of the enzyme activity was nil when FAD was added after the inactivation. Thus, while the covalent attachment of FAD in MAO A is not required for the catalytic activity, it may function as a structural core for the active conformation in the membrane.

Regions of the molecule responsible for substrate specificity of monoamine oxidase A and B: a chimeric enzyme analysis.

To examine regions of the monoamine oxidase (MAO, EC 1.4.3.4) molecule responsible for substrate recognition, a series of these enzymes, in which discrete regions in one molecule were substituted by corresponding sequences of the other, were constructed from the cDNAs of rat liver MAO A and MAO B and were expressed in yeast, Saccharomyces cerevisiae. Substrate specificities of the original and chimeric enzymes were examined in terms of the maximum activity (Vmax) and the affinity (Km) for serotonin, beta-phenylethylamine (PEA), and benzylamine. Chimeric enzymes with the amino-terminal portion (about 220 residues) and the amino-terminal and middle portions (about 400 residues) of MAO A and MAO B, respectively, exhibited substantially the same Km values as those of the parent enzymes. Extension of the substitution in the middle portion of a chimeric enzyme to the second half of the amino-terminal portion resulted in conversion of the Km values for serotonin to those of the counterpart. Data on relative Vmax values of the chimeric enzymes for the three substrates revealed that the relative catalytic activities were mainly determined by the presence of the middle portion. We conclude from these observations that the region between about residues 120-220 and about residues 50-400 is responsible for determination of the substrate specificity of MAO A and MAO B, respectively, while the middle portion, of about residues 220-400, may relate to the relative catalytic activity towards substrates.

Rat monoamine oxidase B expressed in Escherichia coli has a covalently-bound FAD.

Rat liver monoamine oxidase B (MAO B) was expressed in E. coli as catalytically active form, though inclusion bodies of the enzyme were also formed as a major protein in the cell. The active form of the recombinant MAO B exhibited similar properties as rat liver enzyme and localized in membrane of the bacteria. Covalent attachment of FAD to polypeptide chain of the recombinant enzyme was revealed by a labeling experiment with [3H]-pargyline, an irreversible mechanism-based inhibitor, indicating that the covalent linkage of FAD to the apoprotein was formed even in the prokaryotic cell. This observation suggests autocatalytic formation of the linkage in MAO B.

A deletion mutation in the 3' end of the alpha 5(IV) collagen gene in juvenile-onset Alport syndrome.

Alport syndrome is a hereditary progressive glomerular basement membrane disorder in which juvenile-or adult-onset renal failure is often accompanied by sensorineural deafness and ocular abnormalities. Recently, mutations have been found in the type IV collagen alpha 5 chain gene in patients with X-linked Alport syndrome. This study searched for gene mutations in seven unrelated Japanese patients by the use of conventional Southern blot analysis with cDNA probes for the carboxyl-terminal noncollagenous domain that is encoded by exons 46 to 51. A deletion mutation was found in a patient who developed juvenile-onset (age 15) ESRD with typical ultrastructural glomerular basement membrane destruction and sensorineural hearing loss but no characteristic ocular abnormalities. His mother showed hematuria and proteinuria with normal renal function, suggesting that she may be the heterozygous carrier. Exon-specific polymerase chain reaction amplified the coding sequence of exon 48 but not exons 49 to 51. Analysis with pulsed-field gel electrophoresis revealed that the deletion is approximately 10 kb in length and does not involve the CpG island, which is located in the 3' distal site of the gene. Identification of this novel deletion causing juvenile-type Alport syndrome would contribute to elucidating the mechanisms of renal failure progression in the syndrome.

Characterization of the DNA-binding domain of the mouse uterine estrogen receptor using site-specific polyclonal antibodies.

The DNA-binding domain of the mouse uterine estrogen receptor (ER) was characterized using site-specific polyclonal antibodies. The peptides used as antigens have sequences corresponding to amino acids 185-199 and 227-245, the two zinc finger regions of the DNA-binding domain of the human ER, and produced anti-sera designated A-1542 and A-1554, respectively. Mouse uterine nuclear ER and salt-activated 4 S cytosol receptor, as well as 8 S untransformed cytosol receptor, were observed to react with the antisera by Western blot and sucrose density gradient centrifugation analyses indicating that the DNA-binding domain of the 8 S cytosol receptor is not completely masked by heat shock protein 90 or other proteins. Only A-1554 detected a nuclear-specific doublet form of the ER on Western blot analysis. In a gel shift assay, neither antisera altered the pattern of the nuclear ER interaction with the vitellogenin A2 estrogen response element (VRE). In contrast, antiserum A-1554 partially shifted the 8 S cytosol receptor-VRE complex. This concurs with mutational analysis and x-ray crystallography studies with the human ER that have shown that the second finger is not in contact with the DNA. The results of the gel shift assay were confirmed by sucrose density gradient analysis using the same buffer conditions. The nuclear receptor-VRE complex did not react with either antisera, suggesting that when the dimeric nuclear receptor form binds the VRE, the specific receptor epitopes involved with the DNA binding may be blocked and unable to bind the antisera. The cytosol receptor-VRE complex reacted only partially with the second finger antisera A-1554, suggesting that on receptor monomers the second finger epitope is not completely blocked by DNA binding or dimer formation.

Subsite mapping of an acidic amino acid-specific endopeptidase from Streptomyces griseus, GluSGP, and protease V8.

The substrate specificities of an acidic amino acid-specific endopeptidase of Streptomyces griseus, GluSGP, and protease V8 [EC 3.4.21.19] were investigated with peptide p-nitroanilide substrates which have a Glu residue at the P1 position. GluSGP and protease V8 favored Pro and Leu residues at S2, respectively, while the S3 subsite of GluSGP preferred Phe over either Ala or Leu. The S3 subsite of protease V8 preferred Leu over either Ala or Phe. The best substrates for GluSGP and for protease V8 were Boc-Ala-Phe-Pro-Glu-pNA with a Km value of 0.41 mM (0.1 M Tris-HCl, pH 8.8) and Boc-Ala-Leu-Leu-Glu-pNA with a Km value of 0.25 mM (0.1 M phosphate, pH 7.8), respectively. The kcat/Km values for these substrates obtained with GluSGP were about one hundred to twenty thousand times larger than those obtained with protease V8. Protease V8 exhibited a single optimal pH of around 8 for the hydrolysis of Boc-Ala-Ala-Leu-Glu-pNA and Boc-Ala-Leu-Leu-Asp-pNA.

Purification and amino acid sequence of a bitter gourd inhibitor against an acidic amino acid-specific endopeptidase of Streptomyces griseus.

An inhibitor (BGIA) against an acidic amino acid-specific endopeptidase of Streptomyces griseus (Glu S. griseus protease) was isolated from seeds of the bitter gourd Momordica charantia L., and its amino acid sequence was determined. The molecular weight of BGIA based on the amino acid sequence was calculated to be 7419. BGIA competitively inhibited Glu S. griseus protease with an inhibition constant (Ki) of 70 nM, and gel filtration analyses suggested that BGIA forms a 1:1 complex with this protease. However, two other acidic amino acid-specific endopeptidases, protease V8 from Staphylococcus aureus and Bacillus subtilis proteinase (Glu B. subtilis protease), were not inhibited by BGIA. BGIA had no inhibitory activity against chymotrypsin, trypsin, porcine pancreatic elastase, and papain, although subtilisin Carlsberg was strongly inhibited. The amino acid sequence of BGIA shows similarity to potato chymotrypsin inhibitor, barley subtilisin-chymotrypsin inhibitor CI-1 and CI-2, and leech eglin C, especially around the reactive site. Although the residue at the putative reactive site of these inhibitors is leucine or methionine, the corresponding amino acid in BGIA is alanine.

Responsiveness to interleukin 4 and interleukin 2 of peripheral blood mononuclear cells in atopic dermatitis.

Although the pathogenesis of atopic dermatitis (AD) is unknown, many immunologic abnormalities such as high levels of serum IgE and increase of IgE Fc receptor-positive lymphocytes have been demonstrated. Recently, interleukin 4 (IL-4) has been shown to induce enormously the production of IgE and to enhance the expression of IgE Fc receptor by B cells, suggesting the possible involvement of IL-4 in the pathogenesis of AD. We examined IL-4 responsiveness or interleukin 2 (IL-2) responsiveness of peripheral blood mononuclear cells of 31 patients with AD, 19 healthy individuals, and seven patients with other skin diseases. We found that IL-4 responsiveness of AD was higher than that of non-AD control, although IL-2 responsiveness of AD showed no significant change. However, the value of the IL-4 responsiveness did not significantly correlate with the clinical severity, personal history of respiratory allergy, serum IgE level, or clinical course of patients with AD. The hyperresponsiveness to IL-4 detected in AD was not likely to be due to the effects of steroids or anti-mast cell drugs because the value of IL-4 responsiveness was significantly low, compared to AD, in patients with other skin diseases who were treated similarly. Because the T-cell-enriched population, but not the B-cell-enriched population, showed significant proliferation in response to exogenous IL-4 or IL-2, T cells were the main population that reacted in our proliferation assay. These results indicate that IL-4-driven proliferative response may be efficiently operative in T cells in patients with AD.

Purification and characterization of an acidic amino acid-specific endopeptidase of Bacillus subtilis obtained from a commercial preparation (Protease Type XVI, Sigma).

An acidic amino acid-specific endopeptidase was purified from Protease Type XVI (Sigma), a commercial product from culture filtrate of Bacillus subtilis, by a series of column chromatographies on CM-Toyopearl (Fractogel) and Mono-S, guided by activity assay using Boc-Ala-Ala-Pro-Glu-pNA as a substrate. The final preparation was homogeneous on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and reversed-phase HPLC. The molecular weight of the protease was estimated to be 18,000 by gel filtration on TSK gel G3000SWXL column using 6 M guanidine hydrochloride as an eluent, and 17,000 by SDS-PAGE in the presence of 2-mercaptoethanol. The isoelectric point of the protease was 7.7. Studies on the substrate specificity with peptide p-nitroanilides and natural peptides revealed that the protease hydrolyzes the peptide bonds on the carboxyl-terminal side of acidic amino acids, especially of glutamic acid. The protease was completely inactivated by DFP, indicating the serine protease nature of the protease. The activity of the protease was also inhibited by EDTA and GEDTA, and reactivated by Ca2+. The protease contained 1.3 +/- 0.2 mol/mol protein of Ca2+. These results suggest that Ca2+ plays a vital role in the protease activity.

Purification and complex formation analysis of a cysteine proteinase inhibitor (cystatin) from seeds of Wisteria floribunda.

Seeds of Wisteria floribunda contain several kinds of cysteine proteinase inhibitor (cystatin). We purified and characterized one of these inhibitors, named WCPI-3. The molecular weight of WCPI-3 was estimated to be 17,500 and 15,700 by gel filtration and SDS-PAGE, respectively. The isoelectric point was 5.7. WCPI-3 formed an equimolar complex with native papain and the dissociation constant was estimated to be 6.1 nM. Complex formation between WCPI-3 and Cys25-modified papain, such as S-carboxy-methylated or S-carbamoylmethylated papain, could not be observed by gel filtration or native PAGE analysis. A peptide fragment derived from WCPI-3 digested by Achromobacter proteinase (lysyl endopeptidase) had the amino acid sequence of VVAGVNYRFVLK. The VVAG sequence in this fragment corresponds to the conserved sequence QVVAG which is considered to be one of binding regions to cysteine proteinases. The amino acid sequence of the amino-terminal portion (34 residues) of WCPI-3 was highly homologous to that of oryzacystatin from rice seeds.