Identification of endotoxin-positive cells in the rat lung during shock

Summary Following an intravenous administration into rats of a shock-inducing dose of endotoxin (2 mg) the lipopolysaccharide (LPS) was demonstrated immunohistochemically (light and electron microscopy) and determined quantitatively (radio-labelled LPS) in the lung tissue and in isolated alveolar macrophages. At different times after LPS injection morphological investigations of the pulmonary tissue and alveolar macrophages were carried out.One hour after endotoxin treatment 3% of the alveolar macrophages were already LPS-positive. The maximum extent of the immunoperoxidase reaction for endotoxin (100% cells involved) was observed on day 3, the vast majority (98%) of the alveolar macrophages being LPS-positive still on day 14. 0.9% of the injected radio-labelled LPS preparation was found to be associated with lung tissue on day 3. By this time 0.173 µg LPS/10⁶ alveolar macrophages was detected. During the time of ultrastructural investigation endotoxin appeared in the lung only within cells. By their high capacity for storing endotoxin and their numerical superiority the mononuclear phagocytes are the leading LPS-positive cells in the lung, although granulocytes, endothelial cells, and alveolar epithelial cells were sometimes also involved.The accumulation of a high percentage of activated macrophages in the lung seen in the late stage of shock could represent at least one of the main factors leading to damage of pulmonary tissue. The correlation between appearance of LPS-positive macrophages and histological signs of lung tissue injury in the present investigation is striking.     

Re-examination of factors associated with expansion of CGG repeats using a single nucleotide polymorphism in FMR1

In at least 98% of fragile X syndrome cases, the disease results from expansion of the CGG repeat in the 5' end of FMR1. The use of microsatellite markers in the FMR1 region has revealed a disparity of risk between haplotypes for CGG repeat expansion. Although instability appears to depend on both the haplotype and the AGG interspersion pattern of the repeat, these factors alone do not completely describe the molecular basis for the linkage disequilibrium between normal and fragile X chromosomes, in part due to instability of the marker loci themselves. In an effort to better understand the mechanism of dynamic mutagenesis, we have searched for and discovered a single nucleotide polymorphism in intron 1 of FMR1 and characterized this marker, called ATL1, in 564 normal and 152 fragile X chromosomes. The G allele of this marker is found in 40% of normal chromosomes, in contrast to 83% of fragile X chromosomes. Not only is the G allele exclusively linked to haplotypes over-represented in fragile X syndrome, but G allele chromosomes also appear to transition to instability at a higher rate on haplotypes negatively associated with risk of expansion. The two alleles of ATL1 also reveal a highly significant linkage disequilibrium between unstable chromosomes and the 5' end of the CGG repeat itself, specifically the position of the first AGG interruption. The data expand the number of haplotypes associated with FMR1 and specifically allow discrimination, by ATL1 alleles, of single haplotypes with differing predispositions to expansion. Such haplotypes should prove useful in further defining the mechanism of dynamic mutagenesis.      

Na+, K+, and BP homeostasis in man during furosemide: effects of prazosin and captopril

Furosemide increases sodium (Na+) and potassium (K+) excretion but if dietary salt is provided, a compensatory reduction in Na+ and K+ excretion follows which restores neutral balances within 18 to 24 hours. This compensation is not interrupted by blockade of the renin-angiotensin-aldosterone system (RAA) alone with captopril. Since plasma norepinephrine concentration increases after furosemide and alpha 1 adrenoreceptors can mediate enhanced Na+ reabsorption, we administered prazosin (2 mg 6 hr-1) to six normal volunteers consuming a daily intake of 270 mmol of Na+ and 75 mmol of K+, and added captopril (25 mg 6 hr-1) for an additional day to block the RAA system concurrently. Furosemide (40 mg day-1) was given for the last four days. Prazosin given alone before the diuretic reduced (P less than 0.05) BP and plasma angiotensin II (AII) concentration and increased body weight and heart rate. However, when given with furosemide, neither prazosin nor prazosin with captopril modified the short-term natriuretic or kaliuretic responses to furosemide, or the ensuing compensatory reductions in Na+ and K+ excretion. Accordingly, cumulative balances for Na+ and K+ remained neutral over four days of diuretic administration. Neither drug altered the renal responsiveness to the diuretic which was assessed from the relationship between renal Na+ and K+ excretion and diuretic elimination. Although the BP was maintained when furosemide was given alone, when given with prazosin and captopril, the mean BP fell by 13 +/- 5 mm Hg (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Acute inflammatory Demodex-induced pustulosis in an immunocompetent patient related to topical steroid use

Demodex spp. mites are a common colonizer of sebaceous adult skin. Though usually clinically insignificant, demodicosis may be associated with a wide spectrum of skin diseases in immunocompetent hosts, such as erythematotelangiectatic and papulopustular rosacea, Demodex folliculorum, and blepharitis. We present a case of a healthy 9-year-old boy with an exuberant, inflammatory, Demodex-associated pustular eruption of the face, induced by the use of a high-potency topical steroid and successfully treated with oral ivermectin.     

Isolation of a cDNA for the human homolog of MAT-1 oncogene and its expression in human breast cancer cells

Overexpression of mouse MAT-1 oncogene is associated with carcinogensis of mouse mammary epithelial cells. A human cDNA (hMAT) homologous to MAT-1 was isolated from normal human breast tissue. The hMAT cDNA is 1312 bp long and produces a 8.5 kDa peptide in vitro. The hMAT probe hybridized with 2.5 kb RNA in normal human breast epithelial cells from reduction mammoplasty specimens and in human breast cancer cell lines. The extent of hMAT gene expression in human breast cancer cell line was variable, with BT-20, T47-D, and MDA-MB-231 showing about a 10-fold overexpression compared to primary normal human breast epithelial cells, MCF-7, and ZR-75-1.     

Cell proliferation and apoptosis during mammary carcinogenesis in pituitary isografted mice

In the present study, pituitary isografted animals serve asa model for evaluating the changes in differentiation, cellproliferation and programmed cell death (apoptosis) in mammaryepithelial cells during carcinogenesis. The percentage of bromodeoxyuridine(BrdU)-labeled ductal and alveolar cells was significantly higherin pituitary isografted animals than in non-isografted controlanimals. BrdU-labeled cells increased in lobular hyperplasticnodules, keratinized nodules and mammary carcinomas; similarchanges were observed with apoptotic cells, which were rarein mammary glands of adult non-isografted animals (one to threeapoptotic cells per 2000 mammary epithelial cells), but theirnumber increased in hyperplastic lesions and mammary carcinomas.Among hyperplastic nodular lesions, variants with high, moderateand low proliferative activity and/or apoptotic cell death wereidentified, which suggests that they may have different growthpotentials and different propensities for malignant transformation.After removing pituitary isografts, apoptosis occurs in hyperplasticlesions but not in mammary carcinomas implying that malignanttumors are hormone-independent. The dynamics of the changesin apoptotic cell death among various hyperplastic lesions afterremoval of pituitary isografts suggests that these lesions arecomposed of heterogeneous cell populations, as far as the initiationof apoptosis is concerned. Our data indicate that apoptosiscan be used together with cell proliferation as a potentialmarker in characterizing the growth potential and phenotypicdiversity of hyperplastic, premalignant and malignant mammarygland lesions.