Investigation of the genotoxic effect in bone marrow of Swiss albino mice exposed long-term to pyrimethamine

In the present study, we investigated the genotoxic effect of pyrimethamine, which is a drug used in the therapy of toxoplasmosis and malaria, in bone marrow cells of Swiss albino mice exposed to three doses (1, 4, 8 mg/kg) of this agent for eight months orally in vivo. We used a chromosome analysis and micronucleus test for evaluation of genotoxic effect. While a statistically significant change was not determined in numerical chromosome abnormalities, structural chromosome aberrations and micronuclei were increased in a dose-dependent manner by cytogenetic and statistical evaluations.     

Extra-chromosomal telomeric DNA in cells from Atm(-/-) mice and patients with ataxia-telangiectasia

Ataxia-telangiectasia (AT) is an autosomally recessive human genetic disease with pleiotropic defects such as neurological degeneration, immunodeficiency, chromosomal instability, cancer susceptibility and premature aging. Cells derived from AT patients and ataxia-telangiectasia mutated (ATM)-deficient mice show slow growth in culture and premature senescence. ATM, which belongs to the PI3 kinase family along with DNA-PK, plays a major role in signaling the p53 response to DNA strand breaks. Telomere maintenance is perturbed in yeast strains lacking genes homologous to ATM and cells from patients with AT have short telomeres. We examined the length of individual telomeres in cells from ATM(-/-) mice by fluorescence in situ hybridization. Telomeres were extensively shortened in multiple tissues of ATM(-/-) mice. More than the expected number of telomere signals was observed in interphase nuclei of ATM(-/-) mouse fibroblasts. Signals corresponding to 5-25 kb of telomeric DNA that were not associated with chromosomes were also noticed in ATM(-/-) metaphase spreads. Extrachromosomal telomeric DNA was also detected in fibroblasts from AT patients and may represent fragmented telomeres or by-products of defective replication of telomeric DNA. These results suggest a role of ATM in telomere maintenance and replication, which may contribute to the poor growth of ATM(-/-) cells and increased tumor incidence in both AT patients and ATM(-/-) mice.     

Improved high-performance liquid chromatography assay of doxorubicin: Detection of circulating aglycones in human plasma and comparison with thin-layer chromatography

Summary We compared doxorubicin and metabolite pharmacokinetic data obtained from thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC) assay of plasma samples from six patients who had been treated with doxorubicin. Duplicate 1-ml samples were extracted with chloroform: isopropanol (1:1) and assayed using a sensitive HPLC system incorporating a dual pump gradient with tetrahydrofuran as the mobile phase and fluorescence detection. Duplicate 1-ml samples from the same specimens were assayed using a modification of a previously described TLC assay. Areas under the curve for doxorubicin by HPLC (3.36±2.30 M · h) and TLC (4.16±2.50 M · h) were not significantly different (P=0.5). Terminal half-life of doxorubicin by HPLC (28.0±6.98 h) and TLC (23.2±7.8) (P=0.29) and the calculated total-body clearances by HPLC (0.55±0.29 l/min) and TLC (0.45±0.23) (P=0.55) were not significantly different. Areas under the curve for doxorubicinol by HPLC (2.75±1.4 M · h) and TLC (2.53±7.1 M · h) (P=0.73) showed no significant differences. HPLC detected a mixed 7-deoxydoxorubicinol aglycone-doxorubicin aglycone peak, 7-deoxydoxorubicin aglycone, and two nonpolar, unidentified metabolites. TLC detected the following aglycone metabolites: doxorubicin aglycone, doxorubicinol aglycone, 7-deoxydoxorubicinol aglycone, an unidentified polar metabolite, and several unidentified nonpolar metabolites. From these data we conclude that HPLC and TLC detect concentrations of doxorubicin and doxorubicinol from human plasma equally well to concentrations of 7.0 nM (4 pmol injected doxorubicin). Aglycones do circulate in human plasma at concentrations above the detection limits of both assays. Doxorubicinol aglycone, which is detected by TLC but not by HPLC, may be formed from artifactual breakdown of doxorubicinol during TLC development. Unidentified nonpolar compounds seen on HPLC and TLC may represent further doxorubicin metabolism than previously described.     

In vitro pharmacodynamic evaluation of VP-16-213 and implications for chemotherapy

Summary VP-16-213 (Etoposide) is an active antineoplastic agent which has undergone extensive evaluation of clinical dose escalation. To corroborate a putative dose-response relationship, we studied, in a modified clonogenic assay, various doses and durations of exposure. VP-16-213 at doses of 0.01, 0.05, 0.10, 0.50, 1.0, 5.0 and 10.0 g/ml, each with exposure durations of 1, 3, 18, and 30 h, was studied in vitro against two human tumor cell lines, MOLT and 9812. The doses and durations of exposure were chosen to approximate some of the pharmacokinetic values achievable in either standard-dose or high-dose clinical studies. The results, summarized as linear regression lines, demonstrate with statistical significance (p<0.03) that there is correlation between dose and cytotoxicity and between dose x duration of exposure (representing the area under the concentration-time curve) and cytotoxicity. Our in vitro data thus support the concept of intensive use of VP-16-213 to maximize antitumor activity. However, how best to accomplish the manipulation of dose and duration of exposure is not yet clear and will be the subject of future clinical investigations.Supported in part by Grant ROI CA39686 from the NIH (KR Hande)     

Human Milk Virome Analysis: Changing Pattern Regarding Mode of Delivery,Birth Weight,and Lactational Stage

The human milk (HM) microbiota is a significant source of microbes that colonize the infant gut early in life. The aim of this study was to compare transient and mature HM virome compositions, and also possible changes related to the mode of delivery, gestational age, and weight for gestational age. Overall, in the 81 samples analyzed in this study, reads matching bacteriophages accounted for 79.5% (mainly Podoviridae, Myoviridae, and Siphoviridae) of the reads, far more abundant than those classified as eukaryotic viruses (20.5%, mainly Herpesviridae). In the whole study group of transient human milk, the most abundant families were Podoviridae and Myoviridae. In mature human milk, Podoviridae decreased, and Siphoviridae became the most abundant family. Bacteriophages were predominant in transient HM samples (98.4% in the normal spontaneous vaginal delivery group, 92.1% in the premature group, 89.9% in the C-section group, and 68.3% in the large for gestational age group), except in the small for gestational age group (only ~45% bacteriophages in transient HM samples). Bacteriophages were also predominant in mature HM; however, they were lower in mature HM than in transient HM (71.7% in the normal spontaneous vaginal delivery group, 60.8% in the C-section group, 56% in the premature group, and 80.6% in the large for gestational age group). Bacteriophages still represented 45% of mature HM in the small for gestational age group. In the transient HM of the normal spontaneous vaginal delivery group, the most abundant family was Podoviridae; however, in mature HM, Podoviridae became less prominent than Siphoviridae. Myoviridae was predominant in both transient and mature HM in the premature group (all C-section), and Podoviridae was predominant in transient HM, while Siphoviridae and Herpesviridae were predominant in mature HM. In the small for gestational age group, the most abundant taxa in transient HM were the family Herpesviridae and a species of the genus Roseolovirus. Bacteriophages constituted the major component of the HM virome, and we showed changes regarding the lactation period, preterm birth, delivery mode, and birth weight. Early in life, the HM virome may influence the composition of an infant’s gut microbiome, which could have short- and long-term health implications. Further longitudinal mother–newborn pair studies are required to understand the effects of these variations on the composition of the HM and the infant gut virome.     

稀土对甘蔗增产增糖机理的探讨

以盆栽试验为主,结合大田生产试验来研究稀土微肥对甘蔗增产增糖的机理。研究结果表明,稀土能提高甘蔗叶片叶绿素含量,改善叶片的超微结构,增加叶肉细胞和维管束鞘细胞的叶绿体数,增加叶肉细胞叶绿体中的基粒数和基粒片层数,增大叶片光合膜面积,能促进根系生长,提高根系活力,促进根系对N、P、K等营养元素的吸收;能提高甘蔗体内K、Ca、Zn、Cu等元素的水平,而相对降低Mn、Na等元素的水平;能提高甘蔗伸长期叶片酸性转化酶活性,降低成熟期叶片酸性转化酶活性,提高伸长期及成熟期叶片中性转化酶活性,协调甘蔗的生长和蔗糖分的积累,能调节细胞的渗透压,维持细胞膜结构和功能的稳定性和完整性,增强细胞壁的伸缩性,提高甘蔗的抗旱性;能改善质膜的透性,提高其选择吸收能力,减轻高浓度Na~+的毒害,提高甘蔗的耐盐能力。     

Wolcott–Rallison syndrome due to the same mutation (W522X) in EIF2AK3 in two unrelated families and review of the literature*

Ozbek MN, Senée V, Aydemir S, Kotan LD, Mungan NO, Yuksel B, Julier C, Topaloglu AK. Wolcott–Rallison syndrome due to the same mutation (W522X) in EIF2AK3 in two unrelated families and review of the literature. Wolcott‐Rallison syndrome (WRS) is a rare autosomal recessive disorder characterized by an early‐infancy‐onset diabetes mellitus associated with a variety of multisystemic clinical manifestations. Here, we present six patients with WRS, carrying the same homozygous mutation (EIF2AK3‐W522X), from two unrelated Turkish families. This is the largest series of patients with the same mutation for this rare syndrome. In this communication we compare clinical features of these six patients with the other 34 patients who have been reported to date, and review the clinical features of WRS. All WRS patients presented first with symptoms of insulin dependent diabetes mellitus, with a mean age at onset of 2 months. All patients had skeletal dysplasia or early signs of it, and growth retardation. Many of the patients with WRS have been reported to have developmental delay, mental retardation, and learning difficulties; in contrast, none of our patients showed abnormal development at age up to 30 months. Acute attacks of hepatic failure were reported in 23 cases out of 37 patients; in 15 of those 23 cases an acute attack of renal failure accompanied the liver failure. Exocrine pancreatic deficiency has been reported in only four cases other than our four patients. Central hypothyroidism was observed in six of 28 cases. We propose that central hypothyroidism is not a component of WRS, but rather a reflection of euthyroid sick syndrome. Four of our patients experienced severe neutropenia, compared to only five of the 27 other cases, suggesting that the W522X mutation may be specifically associated with neutropenia. Other than the consistent features of diabetes mellitus and epiphyseal dysplasia, WRS patients are otherwise characterized by extensive phenotypic variability that correlates poorly to genotype.     

Paraurethral cysts in female newborns: role of maternal estrogens

Paraurethral or Skene's duct cyst is a rare cause of introital mass in neonates. We report two female newborn cases with paraurethral cysts associated with vaginal bleeding and breast enlargement. These associations raise the question of whether maternal estrogens play a role in the development of paraurethral cysts.