Glibenclamide treatment in a Cantú syndrome patient with a pathogenic ABCC9 gain‐of‐function variant: Initial experience

Cantú syndrome (CS), characterized by hypertrichosis, distinctive facial features, and complex cardiovascular abnormalities, is caused by pathogenic variants in ABCC9 and KCNJ8 genes. These genes encode gain‐of‐function mutations in the regulatory (SUR2) and pore‐forming (Kir6.1) subunits of K_ATP channels, respectively, suggesting that channel‐blocking sulfonylureas could be a viable therapy. Here we report a neonate with CS, carrying a heterozygous ABCC9 variant (c.3347G>A, p.Arg1116His), born prematurely at 32 weeks gestation. Initial echocardiogram revealed a large patent ductus arteriosus (PDA), and high pulmonary pressures with enlarged right ventricle. He initially received surfactant and continuous positive airway pressure ventilation and was invasively ventilated for 4 weeks, until PDA ligation. After surgery, he still had ongoing bilevel positive airway pressure (BiPAP) requirement, but was subsequently weaned to nocturnal BiPAP. He was treated for pulmonary hypertension with Sildenafil, but failed to make further clinical improvement. A therapeutic glibenclamide trial was commenced in week 11 (initial dose of 0.05 mg^–1 kg^–1 day^–1 in two divided doses). After 1 week of treatment, he began to tolerate time off BiPAP when awake, and edema improved. Glibenclamide was well tolerated, and the dose was slowly increased to 0.15 mg^?1 kg^?1day^?1 over the next 12 weeks. Mild transient hypoglycemia was observed, but there was no cardiovascular dysfunction. Confirmation of therapeutic benefit will require studies of more CS patients but, based on this limited experience, consideration should be given to glibenclamide as CS therapy, although problems associated with prematurity, and complications of hypoglycemia, might limit outcome in critically ill neonates with CS.     

Antimicrobial activities against 84 Listeria monocytogenes isolates from patients with systemic listeriosis at a comprehensive cancer center (1955-1997)

Listeriosis is a serious complication in patients undergoing treatment for cancer. We present antimicrobial susceptibility profiles of 84 clinical Listeria monocytogenes isolates. During 1955 to 1997, in vitro susceptibility for penicillin (97.6%), ampicillin (90.7%), erythromycin (98.8%), tetracycline (96.9%), and gentamicin (98.0%) remained unchanged. All isolates were susceptible to amikacin, ciprofloxacin, imipenem, rifampin, trimethoprim-sulfamethoxazole (TMP-SMX), and vancomycin. High prevalence of clindamycin resistance (96.2%) was unexpected. Ampicillin plus gentamicin is standard therapy for systemic listerosis, and TMP-SMX may be used for patients with beta-lactam intolerance. In vitro susceptibility profiles for carbapenem and fluoronated quinolone are promising, although clinical validation is critically needed before routine use is advocated, especially for listeric patients with severe cellular immune defects.     

Use of immunoblotting to detect Aspergillus fumigatus antigen in sera and urines of rats with experimental invasive aspergillosis.

Immunoblotting was used to detect Aspergillus fumigatus antigen in sera and urines of immunosuppressed rats experimentally infected with A. fumigatus. Organisms were administered by both intravenous and intratracheal injections. Intravenously infected rats developed disseminated aspergillosis, but intratracheally infected rats developed pulmonary disease only. Fungal cultures of blood and urine samples from infected rats were negative. In the urines of intravenously infected rats, antigen was detected 24 to 48 h after infection; in the urines of intratracheally infected animals, antigen was detected on days 4 to 5 after infection. Antigen in serum was detected later than antigen in urine was. Following sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting of serum and urine samples, the most strongly reacting antigenic materials were found in the 88-, 40-, 27-, and 20-kilodalton regions. These dominant antigens appeared to be the same as those of control antigens prepared from A. fumigatus grown in vitro. Rabbit antiserum to Aspergillus filtrate antigen was found to be more immunoreactive than antiserum to mycelial or conidial antigen. No mycelium-specific antigens were detected.     

Alzheimer's disease: the relationship between the density of senile plaques, neurofibrillary tangles and A4 protein in human patients.

The numerical density of senile plaques (SP) and neurofibrillary tangles (NFT) as revealed by the Glees silver method was compared with SP and NFT revealed by the Gallyas method and with amyloid (A4) deposits in immunostained sections in 6 elderly cases of Alzheimer's disease. The density of NFT was generally greater and A4 lower in tissue from hippocampus compared with the neocortex suggesting that A4 deposition was less important than the degree of paired helical filament (PHF) related damage in the hippocampus. The density of Glees SP was positively correlated Gallyas SP weakly correlated with A4 deposit number. A stepwise multiple regression analysis which included A4 deposit and Gallyas SP density and accounted for 54% of the variation in Glees SP density. Hence, different populations of SP were revealed by the different staining methods. The results suggested that the Glees method may stain a population of SP in a region of cortex where both amyloid deposition and neurofibrillary changes have occurred.     

In vitro preactivated human T cells engraft in SCID mice and migrate to murine lymphoid tissues.

Mice with severe combined immunodeficiency (SCID) accept grafts of human T and B lymphocytes derived from resting peripheral blood mononuclear cells (PBMC). We wished to determine whether activated human T cells engraft and migrate into lymphoid tissues in SCID mice. PBMC (50 x 10(6)) activated in vitro in a 4-day mixed lymphocyte culture (MLC) were injected into the peritoneum of 12 SCID mice. In 11 of 12 animals killed at 3 or 4 weeks after injection, human cells were detected in cells pooled from lymphoid organs by flow cytometry and by immunohistochemical staining of frozen tissue sections. The percentage of CD45+ cells in the 11 mice ranged from 2% to 45% and the absolute numbers of CD45+ cells recovered from lymphoid organs ranged from 4 x 10(6) to 90 x 10(6). Up to 93% of the human cells expressed the CD3 antigen together with either CD4 or CD8. Human T cells were localized in periarteriolar areas in murine spleens, whereas in the lymph nodes and gut mucosa, the T cells did not show the pattern for T-dependent areas found in human lymphoid tissue. Numerous human plasma cells were detected in the spleen and gut mucosal crypts of engrafted SCID mice. Human IgG was detected in the serum of all 11 engrafted SCID mice. The functional activity of human T cells recovered from murine splenic tissue was very low 3-4 weeks after engraftment.     

Lone star tick-infecting borreliae are most closely related to the agent of bovine borreliosis

Although Borrelia theileri, the agent of bovine borreliosis, was described at the turn of the century (in 1903), its relationship with borreliae causing Lyme disease or relapsing fever remains undescribed. We tested the previously published hypothesis that spirochetes infecting Lone Star ticks (Amblyomma americanum) may comprise B. theileri by analyzing the 16S ribosomal DNAs (rDNAs) and flagellin genes of these spirochetes. B. theileri, the Amblyomma agent, and B. miyamotoi formed a natural group or clade distinct from but most closely related to that of the relapsing fever spirochetes. B. theileri and the Amblyomma agent were 97 and 98% similar at the nucleotide level within the analyzed portions of the 16S rDNA and the flagellin gene respectively, suggesting a recent divergence. The agent of bovine borreliosis might be explored as a surrogate antigen for the as-yet-uncultivatable Amblyomma agent in studies designed to explore the etiology of a Lyme disease-like infection associated with Lone Star ticks.     

Cystic fibrosis: Synthesis of ciliary inhibitor by amniotic cells

The presence of a ciliary inhibitor in media of cultured amniotic cells obtained from a fetus heterozygous for cystic fibrosis has been observed by the oyster gill cilia assay. The chromatographic fraction containing the inhibitor corresponded to eluted fractions chromatographed from cystic fibrosis fibroblast media and serum. An analogous chromatographic fraction from media of cultured amniotic cells from two proportedly normal fetuses did not inhibit cilia. The chromatographic fraction from media of cultured amniotic cells of a fetus at high risk for cystic fibrosis did not inhibit ciliary activity. Serum was collected from this baby seven weeks after birth and also did not inhibit ciliary action, indicating a homozygous normal genotype. These observations may lead to the development of an antenatal test for cystic fibrosis.     

Genotoxicity of naturally occurring indole compounds: correlation between covalent DNA binding and other genotoxicity tests

3-Methylindole (3MI), melatonin (Mel), serotonin (Ser), and tryptamine (Tryp) were evaluated in vitro for their potential to induce DNA adducts, DNA strand breaks, chromosomal aberrations (Abs), inhibition of DNA synthesis, and mutations. All compounds produced DNA adducts in calf thymus DNA in the presence of rat liver S9. In cultured rat hepatocytes, all produced DNA adducts but none induced DNA strand breaks. In Chinese hamster ovary cells, 3MI and Mel produced DNA adducts, Abs, and inhibition of DNA synthesis with and without S9, except that Mel without S9 did not form adducts. Ser formed DNA adducts, was an equivocal Abs inducer, and suppressed DNA synthesis. Tryp induced neither adducts nor Abs, but did suppress DNA synthesis with S9. Ser and Tryp were less cytotoxic than 3MI and Mel. Mel, Ser, and Tryp failed to induce mutations in Salmonella and E. coli strains with or without S9. 3MI and Mel produced DNA adducts but not mutations in Salmonella TA100 with S9. 3MI and its metabolite indole 3-carbinol also did not induce mutations in a shuttle vector system in human cells. The lack of correlation between DNA adducts and other genotoxicity endpoints for these indole compounds may be due to the higher sensitivity of the (32)P-postlabeling adduct assay or it may indicate that the indole-DNA adducts per se are not mutagenic and are not able to induce strand breaks or alkali-labile lesions. The indole-induced Abs may result from cytotoxicity and suppression of DNA synthesis with minimal if any contribution from DNA adducts.