血管内皮细胞生长因子和c-Fos在单基因遗传自然发病型糖尿病小鼠颌下腺中的表达

目的:观察血管内皮细胞生长因子和c-Fos蛋白在db/db自发性糖尿病小鼠颌下腺的表达,及其与糖尿病病程和颌下腺形态学改变的关系。方法:实验于2004-05在承德医学院中心实验室和承德医学院附属医院病理科完成。取3,4,6,8,10月龄db/db(单基因遗传自然发病型)糖尿病小鼠颌下腺(实验组)及相应月龄的db/ m正常小鼠颌下腺(对照组),采用SP免疫组化染色,观察颌下腺血管内皮细胞生长因子、c-Fos阳性表达的变化。结果:①颌下腺血管内皮细胞生长因子阳性细胞数目:实验组3,4,6,8,10月龄高于相应对照组[(11.8±3.35),(17.4±2.61),(20.6±1.92),(26.8±4.85),(28.0±4.22)个/视野;(6.6±0.89),(11.8±1.64),(16.2±3.27),(16.4±3.97),(17.6±1.82)个/视野,P<0.05,0.01],且呈逐渐增加趋势。②颌下腺c-Fos阳性细胞数目:实验组3,4,6月龄低于相应对照组[(6.4±0.65),(7.8±0.84),(7.9±0.65)个/视野;(12.2±0.84),(11.4±0.55),(10.8±0.84)个/视野,P<0.01]。③糖尿病病程的延长,实验组下颌下腺的实质细胞有明显形态学改变,其中腺泡萎缩明显,细胞排列紊乱。结论:①血管内皮细胞生长因子表达在db/db糖尿病小鼠颌下腺中随病程延长表达增加,与糖尿病病程呈正相关。②db/db糖尿病状态下颌下腺实质发生萎缩性形态学变化,颌下腺细胞表达c-Fos蛋白明显降低,可能与其密切相关。     

Recurrent Idiopathic Membranous Nephropathy: Early Diagnosis by Protocol Biopsies and Treatment with Anti‐CD20 Monoclonal Antibodies

Membranous nephropathy (MN) recurs posttransplant in 42% of patients. We compared MN recurrence rates in a historical cohort transplanted between 1990 and 1999 and in a current cohort diagnosed by protocol biopsies, we analyzed the progression of the disease and we assessed the effects of anti‐CD20 antibodies (Rituximab) on recurrent MN. The incidence of recurrent MN was similar in the historical (53%) and the current cohorts (41%), although in the later the diagnosis was made earlier (median, 4[2–21] months vs. 83[6–149], p = 0.002) and the disease was clinically milder. Twelve out of 14 patients (86%) with recurrent MN in the current cohort had progressive increases in proteinuria. Eight recipients were treated with Rituximab after their proteinuria increased from median, 211 mg/day (64–4898) at diagnosis to 4489 (898–13 855) (p = 0.038). Twelve months post‐Rituximab, 75% of patients had either partial (PR) or complete remission (CR). After 24 months 6/7 (86%) had PR/CR and one patient relapsed. Posttreatment biopsies showed resorption of electron dense immune deposits in 6/7 cases and were negative for C3 (4/7) and IgG (3/7). Protocol biopsies allow early diagnosis of subclinical recurrent MN, which is often progressive. Treatment of recurrent MN with Rituximab is promising and should be evaluated in a prospective randomized controlled trial.     

Role of Endothelium/Nitric Oxide and Cyclic AMP in Isoproterenol Potentiation of 17ß-Estradiol-Mediated Vasorelaxation

Background: Calcitonin gene-related peptide (CGRP) is known to have an extremely potent and prolonged vasodilator effect on the coronary arteries. Studies have shown that CGRP increased coronary blood flow and alleviated reperfusion injury in vitro. It is still unknown, however, whether exogenous CGRP has a protective effect on the reperfusion heart associated with cardiopulmonary bypass (CPB). Methods: An in vivo porcine model of CPB was established. Twenty pigs, 10 controls and 10 CGRP used animals (CGRP group), were performed a median sternotomy followed by a standard CPB. All the hearts were arrested for 45 minutes. In the CGRP group, 1mg/kg CGRP was added into the cardioplegia, and another 1mg/kg was reperfused just before the aortic cross-clamp was removed. In both groups, myocardial microvascular perfusion, coronary arterial microvessel diameter and microvessel blood flow were detected by a laser doppler flowmeter and a contact microscope with TV monitor on five consecutive time perioperatively. Result: Myocardial microvascular perfusion was significantly higher and coronary arterial microvessel diameter was larger in the CGRP group on every point of time of reperfusion compared to those in the control group. In the CGRP group, microvessel blood flow also improved significantly than that in the control group during reperfusion. Conclusion: CGRP improves myocardial microcirculation during cardiac ischemia-reperfusion associated with CPB and could become a new, potent myocardial protector.     

Long-read sequencing revealed cooccurrence,host range,and potential mobility of antibiotic resistome in cow feces

While it is well recognized that the environmental resistome is global, diverse, and augmented by human activities, it has been difficult to assess risk because of the inability to culture many environmental organisms, and it is difficult to evaluate risk from current sequence-based environmental methods. The four most important criteria to determine risk are whether the antibiotic-resistance genes (ARGs) are a complete, potentially functional complement; if they are linked with other resistances; whether they are mobile; and the identity of their host. Long-read sequencing fills this important gap between culture and short sequence-based methods. To address these criteria, we collected feces from a ceftiofur-treated cow, enriched the samples in the presence of antibiotics to favor ARG functionality, and sequenced long reads using Nanopore and PacBio technologies. Multidrug-resistance genes comprised 58% of resistome abundance, but only 0.8% of them were plasmid associated; fluroquinolone-, aminoglycoside-, macrolide-lincosamide-streptogramin (MLS)-, and β-lactam–resistance genes accounted for 2.7 to 12.3% of resistome abundance but with 19 to 78% located on plasmids. A variety of plasmid types were assembled, some of which share low similarity to plasmids in current databases. Enterobacteriaceae were dominant hosts of antibiotic-resistant plasmids; physical linkage of extended-spectrum β-lactamase genes (CTX-M, TEM, CMY, and CARB) was largely found with aminoglycoside-, MLS-, tetracycline-, trimethoprim-, phenicol-, sulfonamide-, and mercury-resistance genes. A draft circular chromosome of Vagococcus lutrae was assembled; it carries MLS-, tetracycline- (including tetM and tetL on an integrative conjugative element), and trimethoprim-resistance genes flanked by many transposase genes and insertion sequences, implying that they remain transferrable.

Antibiotic resistance is one of the greatest global public health crises, as more than 700,000 people die from antibiotic resistance-associated disease every year, and the number is predicted to rise dramatically if radical actions are not taken (1). Studies have shown that many clinical antibiotic-resistant genes (ARGs), such as the extended-spectrum β-lactamase (ESBL) CTX-M and the quinolone-resistance gene qnr, have direct links to the environmental resistome (2, 3). The rapid emergence of ARGs in Acinetobacter, making it one of the most difficult gram-negative bacteria to treat, likely acquired its resistance from Pseudomonas, Salmonella, or Escherichia coli mediated by environmental reservoirs (4). In accord with the “One Health” concept, it’s critical to understand the mobility risk of environmental ARGs, as well as their transmission routes to clinical settings (5).The diversity and abundance of ARGs have been well documented in various contexts, such as soils (6), animal feces (7, 8), wastewater sludge (9), and aquatic ecosystems (10), and so forth. ARGs in livestock and poultry manures are particularly noticeable due to the use of antibiotics in animal farming industry (11). Studies have demonstrated that antibiotics and some metals can increase abundance of antibiotic-resistant bacteria (ARB), ARGs, and metal-resistance genes (MRGs) (12). For example, oxytetracycline treatment significantly boosted tetracycline-resistant coliform bacteria in pig manure (13). The long-term presence of antibiotics in animal manure imposes selection on microbes, which likely means functional antibiotic resistance and higher risk of horizontal gene transfer (HGT) compared to other contexts (14). Moreover, large populations of human commensals in animal manure also increases the possibilities for ARG transfer to human-associated pathogens (15).In recent years valuable insights have been gained about environmental resistomes with qPCR and the next-generation sequencing. For example, diverse and high abundance of ARGs were identified in pig manure from three distantly located farms in China with high-throughput qPCR, and further analysis showed positive correlation between ARG abundance and heavy metal concentrations (16). Furthermore, metagenomic sequencing improved our understanding of the antibiotic resistome, mobile genetic elements (MGEs), and their microbial contexts in environmental samples. Widespread cooccurrence patterns of different classes of ARGs and MRGs have been revealed by metagenomic and network analyses (17, 18). However, most studies have estimated ARG risk by abundance quantification of ARG fragments and not the whole gene, nor whether other resistance genes are linked or their potential for transfer, features central to risk.It is now well recognized that risk of ARGs relies on their mobility and host contexts rather than simply their high diversity or abundance (19). MGEs—including plasmids, transposons, and integrative conjugative elements (ICEs)—play key roles in ARG propagation through HGT. ARGs on plasmids suggests higher transfer potential to pathogens, thus posing a larger threat to public health (20). Besides antibiotics, heavy metals, and biocides can also facilitate the enrichment and spread of ARGs and ARBs (21), hence their cooccurrence pattern can provide insights into coselection risks. The third-generation sequencing technologies, such as PacBio and Nanopore, can produce up to hundreds of kilobase reads and provide new opportunities for estimating ARG cooccurrence, mobility, and host range. For example, the structure and chromosomal insertion site of a composite antibiotic resistance island in Salmonella Typhi Haplotype 58 was resolved using Nanopore sequencing (22). The transfer of a tetracycline-resistance–carrying plasmid was observed from Staphylococcus haemolyticus to Staphylococcus aureus by PacBio sequencing (23). Most studies on ARG mobility, however, are conducted on cultured isolates. An approach is needed to assess the mobility of environmental resistomes and their potential risk.Ceftiofur is a third-generation cephalosporin antibiotic approved by the US Food and Drug Administration for therapeutic use in food animals and is widely used in cattle to treat respiratory diseases, foot rot, metritis, and mastitis (24). Resistance to ceftiofur also causes ineffectiveness to many clinically important antibiotics, which are critical to human health (24). Cattle manure is usually recycled to agricultural fields, representing a potential path of ARGs from manure to soils, ground water, and food systems (25, 26). Here, we collected feces from a dairy cow treated with ceftiofur for a uterine infection after calving, a standard treatment for metritis and known to increase the proportion of ceftiofur-resistant E. coli in the manure (27). Our objectives were to: 1) determine the genetic location (chromosomal, ICE-associated, and plasmidic) and hosts of different classes of ARGs; 2) define complete/near-complete plasmids in manure and infer transferability; 3) determine the linkage pattern of ARGs, MRGs, and biocide-resistance genes (BRGs); and 4) define a long-read sequencing method for environmental resistome evaluation. This approach fills the gap between culture-based isolate analyses and sequencing-based surveys and hence improves the ability to assess risk of environmental resistomes.     

Single parents and students achievements—A national tragedy

Can single-parenthood adversely affect children's school achievement? A recent study conducted in the secondary schools of a rural Washington State school district dramatically confirms that it does. Conducted in 1984 by the Eastern Washington University Department of Education, the research project surveyed a remarkably homogenous population of 7th through 12th grade students by administering California achievements Tests and collecting grade point average data. In every instance but one, single-parent students scored lower than their two-parent counterparts. These results and the homogeneous nature of the population suggest that single-parenthood may be the deciding factor in school success for many students. This study reports survey findings and discusses implications for America's public schools.