[EBF1 Promotes the Sensitivity of Cervical Cancer Cells to Cisplatin via Activating FBN1 Transcription]

Cisplatin (DDP) is widely used in the chemotherapy of cervical cancer (CC), the fourth most common female malignancy worldwide. However, some patients progress to chemotherapy resistance, which leads to chemotherapy failure, tumor recurrence, and poor prognosis. Therefore, strategies to identify the regulatory mechanisms underlying CC development and increase tumor sensitivity to DDP will help improve patient survival. This research was designed to ascertain the mechanism of EBF1-dependent regulation of FBN1 which promotes chemosensitivity of CC cells. The expression of EBF1 and FBN1 was measured in CC tissues resistant or sensitive to chemotherapy and in DDP-sensitive or -resistant cells (SiHa and SiHa-DDP cells). SiHa-DDP cells were transduced with lentiviruses encoding EBF1 or FBN1 to evaluate the influence of these two proteins on cell viability, expression of MDR1 and MRP1, and cell aggressiveness. Moreover, the interaction between EBF1 and FBN1 was predicted and demonstrated. Finally, to further verify the EBF1/FB1-dependent mechanism of DDP sensitivity regulation in CC cells a xenograft mouse model of CC was established using SiHa-DDP cells transduced with lentiviruses carrying EBF1 gene and shRNA directed to FBN1 EBF1 and FBN1 showed decreased expression in CC tissues and cells, particularly in those resistant to chemotherapy. Transduction of SiHa-DDP cells with lentiviruses encoding EBF1 or FBN1 lead to decreased viability, IC50, proliferation capacity, colony formation ability, aggressiveness, and increased cell apoptosis. We have shown that EBF1 activates FBN1 transcription by binding to FBN1 promoter region. Additionally, it was revealed that FBN1 silencing reversed the promoting effect of EBF1 overexpression on chemosensitivity of CC cells in vivo. EBF1 facilitated chemosensitivity in CC cells by activating FBN1 transcription.

Exposure and Health Risk Assessment of Per- and Polyfluoroalkyl Substances in Crayfish from the Middle and Lower Reaches of the Yangtze River

Per- and polyfluoroalkyl substances (PFASs) are a novel class of emerging persistent organic pollutants (POPs) owing to their environmental persistence and bioaccumulation. Red swamp crayfish is a major source of exposure to PFASs, while the dietary intake of PFASs from crayfish is still unclear. We investigated the concentrations of PFASs in 130 batches of crayfish and 100 environmental samples from Middle and Lower Reaches of the Yangtze River Delta. Seven Perfluoroalkyl carboxylic acids (PFCAs), 3 Perfluoroalkyl sulfonates (PFSAs), and 6:2 Cl-PFESA were analyzed by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Meanwhile, PFASs exposure levels were examined concretely in four tissues of crayfish and different circulation links. The average daily intake (ADI) risk model was used to evaluate the human health risk of consuming crayfish and suggested that the risk of PFASs exposure is at a low level.

The Hepatoprotective Effect of Leonurine Hydrochloride Against Alcoholic Liver Disease Based on Transcriptomic and Metabolomic Analysis

Excessive alcohol consumption can eventually progress to alcoholic liver disease (ALD). The underlying mechanism of ALD toxicity is primarily associated with oxidative damage. Many alkaloids have been reported to possess potential antioxidative efficacy, while the mechanism of their hepatoprotective activity against ALD is still not clear. In this study, eight alkaloids were selected from a monomer library of Traditional Chinese Medicine and evaluated for their antioxidant activity against ALD by the evaluation of Glutathione (GSH) and Malondialdehyde (MDA). The result suggested that Leonurine hydrochloride (LH) was a potent antioxidant that could reduce alcoholic liver damage. To further investigate the underlying mechanism of LH against ALD, the molecular pathway induced by LH was identified by RNA-seq analyses. Transcriptome data revealed the principal mechanism for the protective effect of LH against ALD might be attributed to the differentially expressed genes (DEGs) of PI3K-AKT, AMPK, and HIF-1 signaling pathways involved in the lipid metabolism. Given the hepatoprotective mechanism of LH is involved in lipid metabolism, the lipid metabolism induced by LH was further analyzed by UHPLC-MS/MS. Metabolome analysis indicated that LH significantly regulated glycerophospholipid metabolism including phosphatidylcholine, 1-acyl-sn-glycero-3-phosphocholine, phosphatidylethanolamine and 1-acyl-sn-glycero-3-phosphoethanolamine in the liver. Overall, this study revealed that the hepatoprotective mechanism of LH against alcoholic liver damage might be associated with the genes involved in glycerophospholipid metabolism.

Small intestinal morphology and sugar transporters expression when consuming diets of different energy levels: comparison between Tibetan and small-tailed Han sheep

Some non-structural carbohydrates, especially starch, escape ruminal fermentation, are converted into glucose, and are absorbed from the small intestine. This glucose provides an important source of energy, and its usage is more efficient than glucose from carbohydrates which are fermented as short chain fatty acids in the rumen and, subsequently, undergo hepatic gluconeogenesis. Tibetan sheep graze on the harsh Qinghai-Tibetan Plateau (QTP) all year round and their carbohydrate and energy intakes fluctuate greatly with seasonal forage availability. Consequently, a high capacity to absorb glucose from the small intestine would be particularly beneficial for Tibetan sheep to allow them to cope with the inconsistent dietary intakes. This study examined how the small intestinal morphology and sugar transporters' expression of Tibetan and Small-tailed Han (Han) sheep respond to fluctuating energy intakes under the harsh conditions of the QTP. Han sheep graze on the QTP only in summer and are generally raised in feedlots. Twenty-four Tibetan sheep and 24 Han sheep, all wethers, were assigned randomly to four groups (n = 6 per breed/group), with each group offered a diet differing in digestible energy content: 8.21, 9.33, 10.45 and 11.57 MJ/kg DM. After 49 d, all sheep were slaughtered, tissues of the small intestine were collected, and measurements were made of the morphology and glucose transporters and the related regulation gene expressions. At intakes of low energy levels, Tibetan sheep had a greater villus surface area in the duodenum, jejunum and ileum and higher mRNA expression of sodium-dependent glucose transporter 1 in the duodenum and ileum (P < 0.05) than Han sheep. In the glucose transporter 2 (GLUT2) mediated glucose absorption pathway, Tibetan sheep had higher GLUT2 and taste receptor family 1 member 2 and 3 mRNA expressions than Han sheep in the duodenum, jejunum and ileum (P < 0.05). We concluded that the differences between breeds indicated a greater glucose absorption capacity in the small intestine of Tibetan than Han sheep, which would confer an advantage to Tibetan over Han sheep to an inconsistent energy intake on the harsh QTP. These findings suggested that ruminants raised under harsh environmental conditions with highly fluctuating dietary intakes, as is often the case in grazing ruminants worldwide, are able to absorb glucose from the small intestine to a greater extent than ruminants raised under more moderate conditions.

Tazarotene gel promotes healing of deep tissue injury in mice

We investigated the efficacy and molecular mechanisms of tazarotene gel for healing deep tissue injury (DTI). We used male C57BL/6J mice to establish a DTI model. Animals were divided randomly into control, tazarotene gel and purilon gel groups. We injected 100 ul tazarotene gel, purilon gel or saline every 48 h for 20 days. Hematoxylin and eosin staining was used to observe pathological changes on days 14 and 21. The mRNA and protein expression of VEGF-α, TGF-β1 and HIF-1α were detected by qRT-PCR and western blot, respectively. Wound sites exhibited accelerated healing by 20 days in the tazarotene gel group. Fewer inflammatory cells and more granulation tissue were found in both experimental groups compared to controls. The mRNA and protein expression of VEGF-α and TGF-β1 in the experimental groups were increased compared to the control group by day 14. Expression of HIF-1α in the experimental groups was significantly less than in the controls. Tazarotene gel promoted wound healing independent of the HIF-1α/VEGF signalling pathway during tissue repair of DTI. Tazarotene and purilon gels exhibited similar macroscopic healing of wounds and expression of genes and proteins.

[Efficacy and safety of endoscopic papillectomy of major duodenal papilla neoplasms]

Objective: To discuss the efficacy and safety of endoscopic papillectomy of major duodenal papilla neoplasms. Methods: The clinical-pathological data of 21 patients who were admitted to the Department of Endoscopy, Cancer Hospital, Chinese Academy of Medical Sciences and underwent endoscopic papillectomy of major duodenal papilla neoplasms from January 2014 to January 2020 were retrospectively studied, their postoperative outcomes and complication were also analyzed. Results: Tweenty-one patients were successfully performed endoscopic papillectomy of major duodenal papilla neoplasms. The resected lesions varied between 0.5-2.8 cm. Completed lesion was resected in 19 cases and lesion blocks in 2 cases. The incidence of postoperative complication was 52.4% (11/21), including 8 cases of postoperative bleeding (38.1%). Five patients stopped bleeding after endoscopic hemostasis and 3 patients stopped after interventional embolization. Two patients experienced perforation (9.5%) and recovered after conservative treatment including anti-inflammatory treatment and abdominal drainage. Five patients had pancreatitis (23.8%) and recovered after treatment with pre-somatostatin and anti-inflammatory rectal suppository. Preoperative pathological results of 21 patients suggested that 11 were high-grade intraepithelial neoplasia and 8 were low-grade intraepithelial neoplasia, and 2 were chronic inflammation. Postoperative pathological results suggested that 4 were adenocarcinoma, and the rest 17 were adenoma. The coincidence rate of preoperative biopsy results and postoperative pathology was 38.1%(8/21), and underestimate of the pathological stage occurred in 11 patients (52.4%) during the preoperative biopsy, overestimate occurred in two patients (9.5%). Four cases had a positive incisal margin. All patients had good prognoses and no death event occurred during the follow-up period. Conclusions: Early-stage major duodenal papilla neoplasms should be treated with aggressive resection. Endoscopic papillectomy of duodenal papilla neoplasms is safe, effective, and can be recommended as the preferred procedure for major duodenal papilla neoplasms.

Energy substrate metabolism in skeletal muscle and liver when consuming diets of different energy levels: comparison between Tibetan and Small-tailed Han sheep

The energy intake of Tibetan sheep on the harsh Qinghai-Tibetan Plateau (QTP) varies greatly with seasonal forage fluctuations and is often below maintenance requirements, especially during the long, cold winter. The liver plays a crucial role in gluconeogenesis and skeletal muscle is the primary tissue of energy expenditure in mammals. Both play important roles in energy substrate metabolism and regulating energy metabolism homeostasis of the body. This study aimed to gain insight into how skeletal muscle and liver of Tibetan sheep regulate energy substrate metabolism to cope with low energy intake under the harsh environment of the QTP. Tibetan sheep (n = 24; 48.5 ± 1.89 kg BW) were compared with Small-tailed Han sheep (n = 24; 49.2 ± 2.21 kg BW), which were allocated randomly into one of four groups that differed in dietary digestible energy densities: 8.21, 9.33, 10.45 and 11.57 MJ /kg DM. The sheep were slaughtered after a 49-d feeding period, skeletal muscle and liver tissues were collected and measurements were made of the activities of the key enzymes of energy substrate metabolism and the expressions of genes related to energy homeostasis regulation. Compared with Small-tailed Han sheep, Tibetan sheep exhibited higher capacities of propionate to glucose conversion and fatty acid oxidation and ketogenesis in the liver, higher glucose utilization efficiency in both skeletal muscle and liver, but lower activities of fatty acid oxidation and protein mobilization in skeletal muscle, especially when in negative energy balance. However, the Small-tailed Han sheep exhibited higher capacities to convert amino acids and lactate to glucose and higher levels of glycolysis and lipogenesis in the liver than Tibetan sheep. These differences in gluconeogenesis and energy substrate metabolism conferred the Tibetan sheep an advantage over Small-tailed Han sheep to cope with low energy intake and regulate whole-body energy homeostasis under the harsh environment of the QTP.

The Diagnostic Performance of Urine Flow Cytometer UF1000i for Urinary Tract Infections

BACKGROUND

Urinary tract infections (UTIs) are one of the most common infectious diseases in clinic. Urine flow cytometry is receiving more and more attention due to its rapid forecast of UTIs.

METHODS

The Urine Flow Cytometer UF1000i has a series of software programs to quantify bacteria (BACT) and white blood cells (WBC), and describe the scatter diagram of bacteria. The UTIs were predicted based on the cutoff values with the Receiver Operating Characteristic (ROC) curves of BACT and WBC counts. To evaluate the diagnostic performance of UF1000i for UTIs, the sensitivity and specificity of 889 urine samples were determined in comparison to the results of urine culture. Meanwhile the bacterial morphology indication of the UF1000i was evaluated in order to help doctors choose antibiotics. The angle of the scatter cloud with the x-axis was used to classify the infected bacteria as bacilli (< 30°) or cocci (≥ 30°).

RESULTS

The best cutoff value of BACT counts for predicting UTIs was 119 per µL, and the sensitivity and specificity were 95.5% and 88.7%, respectively. While the best cutoff value of WBC counts was 81.5 per µL, and the sensitivity and specificity were 77.6% and 76.7%, respectively. In addition, the best cutoff values for females were 583 BACT per µL and 137.5 WBC per µL. They were much higher than for males (118 BACT per µL and 91 WBC per µL). The coincidence of the bacterial morphology information between the UF1000i software indication and the bacterial actual morphology identified by urine culture was 83% (bacilli) and 68% (cocci), respectively.

CONCLUSIONS

Data demonstrated that the performance of BACT counts for UTIs is superior to WBC counts. In addition, the bacterial morphology could preliminarily be predicated by the scatter diagram. Since the urine flow cytometer UF1000i can provide the data of both BACT counts and the scatter diagram, the urine flow cytometry was regarded as a suitable method for screening UTIs. Moreover, it would be better to take gender into consideration when setting the best cutoff value for diagnosis of UTIs in clinic.

[Investigation of pregestational diabetes mellitus in 15 hospitals in Guangdong province]

Objective: To investigate the morbidity, diagnostic profile and perinatal outcome of pregestational diabetes mellitus (PGDM) in 15 hospitals in Guangdong province. Methods: A total of 41 338 women delivered in the 15 hospitals during the 6 months, 195 women with PGDM (PGDM group) and 195 women with normal glucose test result (control group) were recruited from these tertiary hospitals in Guangdong province from January 2016 to June 2016. The morbidity and diagnostic profile of PGDM were analyzed. The complications during pregnancy and perinatal outcomes were compared between the two groups. In the PGDM group, pregnancy outcomes were analyzed in women who used insulin treatment (n=91) and women who did not (n=104). Results: (1) The incidence of PGDM was 0.472%(195/41 338). Diabetes mellitus were diagnosed in 59 women (30.3%, 59/195) before pregnancy, and 136 women (69.7%,136/195) were diagnosed as PGDM after conceptions. Forty-six women (33.8%) were diagnosed by fasting glucose and glycohemoglobin (HbA1c) screening. (2) The maternal age, pre-pregnancy body mass index (BMI) , prenatal BMI, percentage of family history of diabetes, incidence of macrosomia, concentration of low density lipoprotein were significantly higher in PGDM group than those in control group (all P<0.05). Women in PGDM group had significantly higher HbA1c concentration ((6.3±1.3)% vs (5.2±0.4)%) , fasting glucose [(6.3±2.3) vs (4.8±1.1) mmol/L], oral glucose tolerance test (OGTT) -1 h glucose ((12.6±2.9) vs (7.1±1.3) mmol/L) and OGTT-2 h glucose [(12.0±3.0) vs (6.4±1.0) mmol/L] than those in control group (P<0.01). (3) The morbidity of preterm births was significantly higher (11.3% vs 1.0%, P<0.01), and the gestational age at delivery in PGDM group was significantly smaller [(37.6±2.3) vs (39.2±1.2) weeks, P<0.01]. Cesarean delivery rate in the PGDM group (70.8% vs 29.7%) was significantly higher than the control group (P<0.01). There was significantly difference between PGDM group and control in the neonatal male/female ratio (98/97 vs 111/84, P=0.033). The neonatal birth weight in PGDM group was significantly higher ((3 159±700) vs (3 451±423) g, P<0.01) . And the incidence of neonatal hypoglycemia in the PGDM group was higher than the control group (7.7% vs 2.6%, P=0.036). (4) In the PGDM group, women who were treated with insulin had a smaller gestational age at delivery [(36.9±2.9) vs (37.9±2.5) weeks, P<0.01], and the neonates had a higher neonatal ICU (NICU) admission rate (24.2% vs 9.6%, P<0.01). Conclusions: The morbidity of PGDM in the 15 hospitals in Guangdong province is 0.472%. The majority of PGDM was diagnosed during pregnancy; HbA1c and fasting glucose are reliable parameters for PGDM screening. Women with PGDM have obvious family history of diabetes and repeated pregnancy may accelerate the process of diabetes mellitus. Women with PGDM have higher risk for preterm delivery and neonatal hypoglycemia. Unsatisfied glucose control followed by insulin treatment may increase the need for NICU admission.

Upregulated expression of NKG2D and its ligands give potential therapeutic targets for patients with thymoma

The activating receptor NKG2D (natural killer group 2, member D) of natural killer (NK) cells promotes tumor immune surveillance by targeting ligands selectively induced on cancer cells, and thus having an important role in antitumor immune response. Because these ligands are not widely expressed on healthy adult tissue, NKG2D ligands may present as useful target for immunotherapeutic approaches in cancer. In this study, to elucidate the role of NKG2D-NKG2D ligand interaction in thymoma tissues and to evaluate the potential role of NKG2D ligands as therapeutic target for thymoma, we examined the expression of NKG2D and its specific ligands: MICA (major histocompatibility complex class I chain-related protein A), MICB (major histocompatibility complex class I chain-related protein B) and ULBP (UL16-binding protein) in 36 thymomas (6 subtype A, 6 subtype AB, 8 subtype B1, 5 subtype B2, 6 subtype B3 and 5 subtype C), 15 thymic atrophy and 8 thymic hyperplasia by immunohistochemistry and reverse transcription-real-time-PCR methods. We demonstrated that both mRNA and protein levels of NKG2D, MICA, MICB and ULBP were upregulated in six types of thymomas compared with those in atrophic thymus or proliferating thymus. Furthermore, the NKG2D ligands were found to be frequently coexpressed on thymoma cells. Furthermore, the expression of MICA, MICB and ULBP in subtype C was higher compared with those in subtype A, AB, B1, B2 and B3. Thus, we concluded that high expressions of NKG2D, MICA, MICB and ULBP1 were shown in patients with thymoma, and this may enhance the recognition function of NK cells to eliminate tumor cells. MICA, MICB and ULBP presented an attractive target for thymoma therapy. The abnormal expression of NKG2D, MICA, MICB and ULBP1 can provide us with evidence of the occurrence of thymoma and could also be used as a target in the treatment of thymoma.

Runx1 is required for hematopoietic defects and leukemogenesis in Cbfb-MYH11 knock-in mice

CBFβ-SMMHC, the fusion protein generated by the chromosome 16 inversion fusion gene, CBFB-MYH11, is known to initiate leukemogenesis. However, the mechanism through which CBFβ-SMMHC contributes to leukemia development is not well understood. Previously it was proposed that CBFβ-SMMHC acts by dominantly repressing the transcription factor RUNX1, but we recently showed that CBFβ-SMMHC has activities that are independent of RUNX1 repression. In addition, we showed that a modified CBFβ-SMMHC with decreased RUNX1 binding activity accelerates leukemogenesis. These results raise questions about the importance of RUNX1 in leukemogenesis by CBFβ-SMMHC. To test this, we generated mice expressing Cbfb-MYH11 in a Runx1 deficient background, resulting from either homozygous Runx1 null alleles (Runx1^−/−) or a single dominant negative Runx1 allele (Runx1^+/lz). We found that loss of Runx1 activity rescued the differentiation defects induced by Cbfb-MYH11 during primitive hematopoiesis. During definitive hematopoiesis, RUNX1 loss also significantly reduced the proliferation and differentiation defects induced by Cbfb-MYH11. Importantly, Cbfb-MYH11 induced leukemia had much longer latency in Runx1^+/lz mice than in Runx1 sufficient mice. These data indicate that Runx1 activity is critical for Cbfb-MYH11 induced hematopoietic defects and leukemogenesis.

First Report of a Tospovirus in Mulberry

Mulberry (Morus alba L.) is an economically important crop grown widely throughout Asia. Various virus-like symptoms including mosaics, vein banding, and chlorotic ringspots have been observed and reported on mulberry trees in China and Japan for decades. However, the etiology of mulberry viral diseases is generally understudied, although two mulberry-infecting viruses, Mulberry latent virus (genus Carlavirus) (2) and Mulberry ringspot virus (genus Nepovirus) (3), have been partially characterized. In a recent (2010 to 2011) field survey in Guangxi Province, China, supported by the local government, the incidence of virus-like diseases of mulberry ranged between 40 and 80%. To identify the viruses infecting mulberry, deep sequencing of small RNAs (4) was conducted using an Illumina Genome Analyzer. Small RNAs were isolated from five samples of mulberry leaves showing various virus-like symptoms and sequenced. Among the contigs assembled, a 445-bp contig (GenBank Accession No. JX268597) was found to share 76.6% nucleotide identity and 83.0% amino acid identity to Groundnut bud necrosis virus (genus Tospovirus, family Bunyaviridae; Accession Nos. U42555 and AAC55521). To obtain a longer cDNA fragment of this virus, a reverse transcription (RT)-PCR was done with primers MV-N-F (5'-AAGCCATCAATGTGCCTCCGGA-3') and MV-N-R (5'-AACACCATGTCTACCGTCCGTC-3') that align to the S-RNA sequence encompassing the nucleocapsid (N) gene and a portion of the intergenic region (IGR) of the Tospovirus. PCR products of about 1,000 bp were successfully amplified from the total RNA of the three mulberry samples (sl-1, xcsy-1, and xcsy-4) showing vein banding symptoms, but not from asymptomatic mulberry (jk-1). These PCR products were cloned and sequenced. The lengths of the amplicons were 1,027 bp (isolate sl-1, JX173786), 987 bp (isolate xcsy-1, JX173787), and 979 bp (isolate xcsy-4, JX173788) and the partial IGRs of the sl-1, xcsy-1, and xcsy-4 isolates were 187 bp, 147 bp, and 139 bp, respectively. The coding regions for the N protein were 831 bp and the deduced proteins of 277 amino acid residues were 100% identical for all three isolates. Since the N protein of this virus shared up to only 74.4% identity to other tospoviruses (74.4% to Capsicum chlorosis virus, ABB83818; and 71.5% to Watermelon bud necrosis virus, ABY79095), it may represent a new member of the Tospovirus genus, temporarily named Mulberry vein banding virus (MuVBV), according to the species demarcation criteria for the Bunyaviridae (1). To the best of our knowledge, this is the first report of a Tospovirus infecting M. alba. In an RT-PCR screening of 48 randomly selected mulberry samples suspected to be virus-infected, 32 were MuVBV-positive. Giving the high incidence and the high yield loss associated with Tospovirus and the presence of thrips, suspected vectors for the virus, MuVBV may represent a substantial threat to the silkworm industry in China. References: (1) M. Q. K. Andrew et al. Virus Taxonomy: 9th Report of the ICTV. Elsevier Academic Press, San Diego, 2012. (2) T. Tsuchizaki. Annu. Phytopath. Soc. Japan 42:304, 1976. (3) T. Tsuchizaki et al. Annu. Phytopath. Soc. Japan 37:266, 1971. (4) Q. Wu et al. PNAS. 107:1606, 2010.

Mechanisms and management of doxorubicin cardiotoxicity

Doxorubicin is an effective anti-tumor agent with a cumulative dose-dependent cardiotoxicity. In addition to its principal toxic mechanisms involving iron and redox reactions, recent studies have described new mechanisms of doxorubicin-induced cell death, including abnormal protein processing, hyper-activated innate immune responses, inhibition of neuregulin-1 (NRG1)/ErbB(HER) signalling, impaired progenitor cell renewal/cardiac repair, and decreased vasculogenesis. Although multiple mechanisms involved in doxorubicin cardiotoxicity have been studied, there is presently no clinically proven treatment established for doxorubicin cardiomyopathy. Iron chelator dexrazoxane, angiotensin converting enzyme (ACE) inhibitors, and β-blockade have been proposed as potential preventive strategies for doxorubicin cardiotoxicity. Novel approaches such as anti-miR-146 or recombinant NRG1 to increase cardiomyocyte resistance to toxicity may be of interest in the future.

SARS-coronavirus modulation of myocardial ACE2 expression and inflammation in patients with SARS

BACKGROUND

Angiotensin converting enzyme 2 (ACE2), a monocarboxylase that degrades angiotensin II to angiotensin 1-7, is also the functional receptor for severe acute respiratory syndrome (SARS) coronavirus (SARS-CoV) and is highly expressed in the lungs and heart. Patients with SARS also suffered from cardiac disease including arrhythmias, sudden cardiac death, and systolic and diastolic dysfunction.

MATERIALS AND METHODS

We studied mice infected with the human strain of the SARS-CoV and encephalomyocarditis virus and examined ACE2 mRNA and protein expression. Autopsy heart samples from patients who succumbed to the SARS crisis in Toronto (Canada) were used to investigate the impact of SARS on myocardial structure, inflammation and ACE2 protein expression.

RESULTS

Pulmonary infection with the human SARS-CoV in mice led to an ACE2-dependent myocardial infection with a marked decrease in ACE2 expression confirming a critical role of ACE2 in mediating SARS-CoV infection in the heart. The SARS-CoV viral RNA was detected in 35% (7/20) of autopsied human heart samples obtained from patients who succumbed to the SARS crisis during the Toronto SARS outbreak. Macrophage-specific staining showed a marked increase in macrophage infiltration with evidence of myocardial damage in patients who had SARS-CoV in their hearts. The presence of SARS-CoV in the heart was also associated with marked reductions in ACE2 protein expression.

CONCLUSIONS

Our data show that SARS-CoV can mediate myocardial inflammation and damage associated with down-regulation of myocardial ACE2 system, which may be responsible for the myocardial dysfunction and adverse cardiac outcomes in patients with SARS.

MN1 overexpression is an important step in the development of inv(16) AML

The gene encoding the transcriptional co-activator MN1 is the target of the reciprocal chromosome translocation (12;22)(p13;q12) in some patients with acute myeloid leukemia (AML). In addition, expression array analysis showed that MN1 was overexpressed in AML specified by inv(16), in some AML overexpressing ecotropic viral integration 1 site (EVI1) and in some AML without karyotypic abnormalities. Here we describe that mice receiving transplants of bone marrow (BM) overexpressing MN1 rapidly developed myeloproliferative disease (MPD). This BM also generated myeloid cell lines in culture. By mimicking the situation in human inv(16) AML, forced coexpression of MN1 and Cbfbeta-SMMHC rapidly caused AML in mice. These findings identify MN1 as a highly effective hematopoietic oncogene and suggest that MN1 overexpression is an important cooperative event in human inv(16) AML.

Identification of genes that synergize with Cbfb-MYH11 in the pathogenesis of acute myeloid leukemia

Acute myeloid leukemia subtype M4 with eosinophilia is associated with a chromosome 16 inversion that creates a fusion gene CBFB-MYH11. We have previously shown that CBFB-MYH11 is necessary but not sufficient for leukemogenesis. Here, we report the identification of genes that specifically cooperate with CBFB-MYH11 in leukemogenesis. Neonatal injection of Cbfb-MYH11 knock-in chimeric mice with retrovirus 4070A led to the development of acute myeloid leukemia in 2-5 months. Each leukemia sample contained one or a few viral insertions, suggesting that alteration of one gene could be sufficient to synergize with Cbfb-MYH11. The chromosomal position of 67 independent retroviral insertion sites (RISs) was determined, and 90% of the RISs mapped within 10 kb of a flanking gene. In total, 54 candidate genes were identified; six of them were common insertion sites (CISs). CIS genes included members of a zinc finger transcription factors family, Plag1 and Plagl2, with eight and two independent insertions, respectively. CIS genes also included Runx2, Myb, H2T24, and D6Mm5e. Comparison of the remaining 48 genes with single insertion sites with known leukemia-associated RISs indicated that 18 coincide with known RISs. To our knowledge, this retroviral genetic screen is the first to identify genes that cooperate with a fusion gene important for human myeloid leukemia.

Molecular cloning, genetic mapping, and expression analysis of four zebrafish c/ebp genes

The CCAAT/enhancer binding protein family (C/EBP) are transcription factors that play integral roles in the development and function of many organ systems, including hematopoietic cells, adipose tissues, and liver. We have identified and characterized putative zebrafish orthologs of mammalian C/EBP alpha, beta, gamma, and delta using low-stringency hybridization screening and computer searches of the GenBank EST database. c/ebpa and g were mapped within 1 cM of each other on linkage group (LG) 7, syntenic with human CEBPA and G genes on chromosome 19. c/ebpb was mapped to LG8, and c/ebpd was mapped to LG24, on the same LG as a recently identified unique c/ebp in zebrafish, c/ebp1. The mapping of these genes established new syntenic relationships between LG8 and human chromosome 20, extended existing synteny between LG7 and human chromosome 19, and confirmed the synteny between LG24 and human chromosome 8. In addition, these syntenies between zebrafish and human chromosomes are also conserved in the mouse genome. To characterize the expression of these genes, RNA in situ hybridization in embryos of wild type and a hematopoietic mutant, cloche, was performed. The results showed that zebrafish c/ebpa, b, g, and d were expressed in many embryonic tissues. c/ebpa and b were expressed in a subset of hematopoietic cells in a region consistent with myeloid expression. In addition, there was expression of c/ebpa and b in the liver and c/ebpa, b, and d in regions of the gastrointestinal tract. The expression of the c/ebps may serve as important markers for analysis of myelopoiesis, hepatic development, and other developmental processes in the future.

The role of continuous positive airway pressure in the treatment of congestive heart failure

Congestive heart failure (CHF) is a serious medical condition frequently associated with sleep-related breathing disorders, which remain underdiagnosed and undertreated. Recent studies have provided important insight into the pathophysiology of sleep apnea syndrome in patients with CHF, with potential therapeutic implications. In addition to abolition of sleep apnea, continuous positive airway pressure (CPAP) treatment can improve cardiac function and relieve symptoms of CHF. Postulated mechanisms include beneficial hemodynamic effects on ventricular remodeling, unloading of fatigued respiratory muscles, and neurohormonal modulation. Although medium-term studies using CPAP to treat sleep-related breathing disorders associated with CHF have been encouraging, more definitive data from ongoing large clinical trials are necessary to clarify its therapeutic role.

Effect of hyperoxia on left ventricular function and filling pressures in patients with and without congestive heart failure

STUDY OBJECTIVES

To determine the effects of hyperoxia on left ventricular (LV) function in humans with and without congestive heart failure (CHF).

DESIGN

An acute physiologic study of the effect of hyperoxia on right-heart hemodynamics, LV contractility (peak positive rate of rise of LV pressure [+dP/dt]), time constant of isovolumic left ventricular relaxation (tau), and LV filling pressures.

SETTING

Bayer Cardiovascular Clinical Research Laboratory at the Mount Sinai Hospital, Toronto, Ontario.

PATIENTS

Sixteen patients with stable CHF and 12 subjects with normal LV function received the hyperoxia intervention.

INTERVENTIONS

Patients received 21% O(2) by a nonrebreather mask, followed by 100% O(2) for 20 min, and 21% O(2) for a 10-min recovery period.

RESULTS

In response to hyperoxia, there was a 22 +/- 6% increase in LV end-diastolic pressure (LVEDP) in the CHF group and a similar 29 +/- 14% increase in LVEDP in the normal LV function group (p < 0.05 for both; mean +/- SEM). Hyperoxia was also associated with a prolongation in tau of 10 +/- 2% in the CHF group (p < 0.05) and 8 +/- 2% in the normal LV function group (p < 0.05). No changes in +dP/dt were observed in either group.

CONCLUSIONS

Hyperoxia was associated with impairment of cardiac relaxation and increased LV filling pressures in patients with and without CHF. These observations indicate that caution should be used in the administration of high inspired O(2) fractions to normoxic patients, especially in the setting of CHF.

Function of the inv(16) fusion gene CBFB-MYH11

Inv(16)(p13q22) is associated with acute myeloid leukemia subtype M4Eo, which is characterized by the presence of myelomonocytic blasts and atypical eosinophils. This chromosomal rearrangement results in the fusion of CBFB and MYH11 genes. Mouse models indicate that the fusion gene, Cbfb-MYH11, inhibits differentiation of hematopoietic cells. Although expression of Cbfb-MYH11 is not sufficient for leukemogenesis, a combination of Cbfb-MYH11 and additional mutations can lead specifically to the development of myeloid leukemia. Normally, CBFbeta interacts with CBFalpha to form a transcriptionally active nuclear complex. In vitro studies indicate that expression of CBFB-MYH11 leads to sequestration of CBFalpha2 in the cytoplasm. It also has been shown to inhibit CBF-mediated transactivation, slow cell cycle progression, delay the apoptotic response to DNA damaging agents, and protect CBFalpha2 from degradation. The importance of these functions in vivo remains to be determined.

Blood pressure cuff compression injury of the radial nerve

We describe a 19-year-old man who underwent emergency laparotomy for perforated peptic ulcer. He was otherwise healthy before this admission with no history of diabetes mellitus or neuropathy. A standard-size adult blood pressure cuff connected to a Dinamap monitor, set to cycle automatically every 3 minutes was affixed to his left upper extremity during surgery. One day after the operation he complained of numbness over the dorsum of the left hand and wrist drop. Physical examination revealed 0/5 muscle power of the left wrist and finger extensor muscles with reduced sensation on the radial aspect of the dorsum of the same hand. A diagnosis of acute radial nerve injury was made and rehabilitation was started. The wrist numbness and sensation improved with physical therapy, and he was discharged 9 days after the operation with an active wrist splint. He continued with rehabilitation on an out-patient basis. The muscle power of the wrist extensors gradually improved after three months of physical therapy and reverted to completely normal one month later. Locating the cuff higher on the arm, away from the elbow joint, to avoid the most superficial portion of radial nerve, may prevent this type of compression injury especially in asthenic patients.

A novel myeloid-restricted zebrafish CCAAT/enhancer-binding protein with a potent transcriptional activation domain

The CCAAT/enhancer-binding protein (C/EBP) family consists of transcription factors essential for hematopoiesis. The defining feature of the C/EBPs is a highly conserved carboxy-terminal bZIP domain that is necessary and sufficient for dimerization and DNA binding, whereas their amino-terminal domains are unique. This study reports a novel c/ebp gene (c/ebp1) from zebrafish that encodes a protein homologous to mammalian C/EBPs within the bZIP domain, but with an amino terminus lacking homology to any C/EBP or to any known sequence. In zebrafish embryos, c/ebp1 expression was initially observed in cells within the yolk sac circulation valley at approximately the 16-to 18-somite stage, and at 24 hours postfertilization (hpf), also in circulating cells. Most c/ebp1(+) cells also expressed a known early macrophage marker, leukocyte-specific plastin (l-plastin). Expression of both markers was lost in cloche, a mutant affecting hematopoiesis at the level of the hemangioblast. Expression of both markers was retained in m683 and spadetail, mutants affecting erythropoiesis, but not myelopoiesis. Further, c/ebp1 expression was lost in a mutant with defective myelopoiesis, but intact erythropoiesis. These data suggest that c/ebp1 is expressed exclusively in myeloid cells. In electrophoretic mobility shift assays, c/ebp1 was able to bind a C/EBP consensus DNA site. Further, a chimeric protein containing the amino-terminal domain of c/ebp1 fused to the DNA-binding domain of GAL4 induced a GAL4 reporter 4000-fold in NIH3T3 cells. These results suggest that c/ebp1 is a novel member of the C/EBP family that may function as a potent transcriptional activator in myeloid cells.

Left ventricular performance during prolonged exercise: absence of systolic dysfunction

We assessed left ventricular systolic and diastolic performance during and after prolonged exercise under controlled conditions in a group of healthy, trained men. Previous studies have examined the effects of prolonged effort on left ventricular function, yet it remains unclear whether or not left ventricular dysfunction (e.g. cardiac fatigue) can be produced under such conditions. We studied 15 healthy men, aged 27+/-1 years (mean+/-S.E.M.). Subjects exercised on bicycles at a constant work rate (60% of maximum oxygen uptake per min) for 150 min. Measurements of gas exchange, blood pressure and haematocrit were obtained, concurrent with the assessment of left ventricular function using equilibrium radionuclide angiography, at rest, during exercise (every 30 min) and after 30 min of recovery. Fluid replacement was provided and monitored during the exercise period. The baseline resting and exercise ejection fractions were 66+/-2% and 78+/-2% respectively. During exercise, subjects consumed 1816+/-136 ml of fluid, and the haematocrit had increased at 120 min of exercise (from 47.2%+/-0.6 to 49.9+/-0.8%; P<0.05). There was no change in either systolic or diastolic blood pressure throughout the exercise period, but heart rate drifted upwards from 141+/-2 beats/min after 30 min to 154+/-3 beats/min after 150 min (P<0.05). There was a small decline (8%; P<0.05) in end-diastolic volume at 150 min. No changes were observed in left ventricular ejection fraction, the pressure/volume ratio or end-systolic volume. After 30 min of sitting in recovery, heart rate was still higher than the pre-exercise value (84+/-3 compared with 69+/-2 beats/min; P<0.05), as were measures of peak filling rate and time to peak filling (P<0.05). The ejection fraction in the post-exercise recovery period was similar to the pre-exercise value. The results indicate that prolonged exercise of moderate duration may not induce abnormal left ventricular systolic function or cardiac fatigue during exercise.

Core-binding factor beta (CBFbeta), but not CBFbeta-smooth muscle myosin heavy chain, rescues definitive hematopoiesis in CBFbeta-deficient embryonic stem cells

Core-binding factor beta (CBFbeta) is the non-DNA-binding subunit of the heterodimeric CBFs. Genes encoding CBFbeta (CBFB), and one of the DNA-binding CBFalpha subunits, Runx1 (also known as CBFalpha2, AML1, and PEBP2alphaB), are required for normal hematopoiesis and are also frequent targets of chromosomal translocations in acute leukemias in humans. Homozygous disruption of either the Runx1 or Cbfb gene in mice results in embryonic lethality at midgestation due to hemorrhaging in the central nervous system, and severely impairs fetal liver hematopoiesis. Results of this study show that Cbfb-deficient mouse embryonic stem (ES) cells can differentiate into primitive erythroid colonies in vitro, but are impaired in their ability to produce definitive erythroid and myeloid colonies, mimicking the in vivo defect. Definitive hematopoiesis is restored by ectopic expression of full-length Cbfb transgenes, as well as by a transgene encoding only the heterodimerization domain of CBFbeta. In contrast, the CBFbeta-smooth muscle myosin heavy chain (SMMHC) fusion protein generated by the inv(16) associated with acute myeloid leukemias (M4Eo) cannot rescue definitive hematopoiesis by Cbfb-deficient ES cells. Sequences responsible for the inability of CBFbeta-SMMHC to rescue definitive hematopoiesis reside in the SMMHC portion of the fusion protein. Results also show that the CBFbeta-SMMHC fusion protein transdominantly inhibits definitive hematopoiesis, but not to the same extent as homozygous loss of Runx1 or Cbfb. CBFbeta-SMMHC preferentially inhibits the differentiation of myeloid lineage cells, while increasing the number of blastlike cells in culture.

Zebrafish homolog of the leukemia gene CBFB: its expression during embryogenesis and its relationship to scl and gata-1 in hematopoiesis

Mammalian CBFB encodes a transcription factor (CBF beta) that in combination with CBF alpha 2 binds to specific DNA sequences and regulates expression of a number of hematopoietic genes. CBFB is associated with human leukemias through a chromosome 16 inversion and is essential for definitive hematopoiesis during mouse embryo development. We have isolated a zebrafish cbfb complementary DNA (cDNA) clone from a zebrafish kidney cDNA library. This cbfb is highly homologous to human and mouse CBFB/Cbfb genes at both the DNA and protein level. In biochemical analyses, cbfbeta binds to human CBF alpha 2 and enhances its DNA binding. During zebrafish development, cbfb is expressed in the lateral plate mesoderm at tail bud stage and in the intermediate cell mass (ICM, the location of embryonic hematopoiesis) between the 21- to 26-somite stages. The cbfb is also expressed in Rohon-Beard cells, cranial nerve ganglia, hindbrain, retina, branchial arches, jaw, and fin buds. Expression of cbfb is decreased or absent in the ICM and Rohon-Beard cells in some hematopoietic mutants and is unaffected in others. We have also analyzed the expression of scl and gata-1 in the same hematopoietic mutants to ascertain the relative order of these transcription factors to cbfb in zebrafish hematopoiesis. Our results indicate that cbfb is expressed in early hematopoietic progenitors and that its expression pattern in the hematopoietic mutants is similar to that of scl. (Blood. 2000;96:4178-4184)

Effects of estrogen replacement on infarct size, cardiac remodeling, and the endothelin system after myocardial infarction in ovariectomized rats

BACKGROUND

Estrogen may increase the long-term survival of women who have suffered from a myocardial infarction (MI). We examined the acute and chronic influence of estrogen on MI in the rat left coronary artery ligation model.

METHODS AND RESULTS

Female Sprague-Dawley rats (10 to 12 weeks, n=93), divided into 3 groups (rats with intact ovaries, ovariectomized rats administered 17beta-estradiol [17beta-E(2)] replacement, and ovariectomized rats administered placebo 2 weeks before MI), were randomized to left coronary artery ligation (n=66) or sham-operated (n=27) groups. Ten to 11 weeks after MI, rats were randomly assigned to either (1) assessment of left ventricular (LV) function and morphometric analysis or (2) measurement of cardiopulmonary mRNA expression of preproendothelin-1 and endothelin A and B receptors. Acutely, estrogen was associated with a trend toward increased mortality. Infarct size was increased in the 17beta-E(2) group compared with the placebo group (42+/-2% versus 26+/-3%, respectively; P:=0.01). Chronically, wall tension was normalized through a reduction in LV cavity size with estrogen treatment (419+/-41 mm Hg/mm for 17beta-E(2) versus 946+/-300 mm Hg/mm for placebo, P:=0.039). In the LV, there was a 2.5-fold increase in endothelin B mRNA expression after MI in placebo-treated rats (P:=0.004 versus sham-operated rats) that was prevented in the 17beta-E(2) group (P:=NS versus sham-operated rats).

CONCLUSIONS

These results suggest that estrogen is detrimental at the time of MI or early post-MI period, resulting in an increased size of infarct or infarct expansion, but chronically, it can normalize wall tension and inhibit LV dilatation, which may in turn lead to increased long-term survival. Regulation of the endothelin system, particularly the expression of the endothelin B receptor, may contribute to these estrogenic effects.

Pulmonary valve replacement in adults late after repair of tetralogy of fallot: are we operating too late?

OBJECTIVES

The purpose of this study is to evaluate right ventricular (RV) volume and function after pulmonary valve replacement (PVR) and to address the issue of optimal surgical timing in these patients.

BACKGROUND

Chronic pulmonary regurgitation (PR) following repair of tetralogy of Fallot (TOF) leads to RV dilation and an increased incidence of sudden cardiac death in adult patients.

METHODS

We studied 25 consecutive adult patients who underwent PVR for significant PR late after repair of TOF. Radionuclide angiography was performed in all at a mean of 8.2 months (+/- 8 months) before PVR and repeated at a mean of 28.0 months (+/- 22.8 months) after the operation. Right ventricular (RV) end-systolic volume (RVESV), RV end-diastolic volume (RVEDV) and RV ejection fraction (RVEF) were measured.

RESULTS

Mean RVEDV, RVESV and RVEF remained unchanged after PVR (227.1 ml versus 214.9 ml, p = 0.74; 157.4 ml versus 155.4 ml, p = 0.94; 35.6% versus 34.7%, p = 0.78, respectively). Of the 10 patients with RVEF > or = 0.40 before PVR, 5 patients (50%) maintained a RVEF > or = 0.40 following PVR, whereas only 2 out of 15 patients (13%) with pre-operative values <0.40 reached an RVEF > or = 0.40 postoperatively (p < 0.001).

CONCLUSIONS

Right ventricular recovery following PVR for chronic significant pulmonary regurgitation after repair of TOF may be compromised in the adult population. In order to maintain adequate RV contractility, pulmonary valve implant in these patients should be considered before RV function deteriorates.

Function of CBFbeta/Bro proteins

Mammalian core binding factor beta (CBFbeta) and Drosophila Brother (Bro) and Big-brother (Bgb) proteins are transcription factors that dimerize with mammalian Runx and Drosophila Runt and Lozenge proteins and augment their DNA binding affinity and transcriptional potency. CBFbeta is essential for development and sustenance of definitive hematopoiesis during mouse embryogenesis. Bro and Bgb are required for Runt/Lozenge functions in Drosophila development. CBFbeta contributes to leukemogenesis since the CBFB gene is specifically and consistently mutated by a chromosome 16 inversion found in patients with acute myeloid leukemia subtype M4Eo. The ubiquitous expression pattern of the CBFB gene suggests that it may play important roles in many other organ systems.

Effects of continuous positive airway pressure on cardiovascular outcomes in heart failure patients with and without Cheyne-Stokes respiration

BACKGROUND

Continuous positive airway pressure (CPAP) improves cardiac function in patients with congestive heart failure (CHF) who also have Cheyne-Stokes respiration and central sleep apnea (CSR-CSA). However, the effects of CPAP in CHF patients without CSR-CSA have not been tested, and the long-term effects of this treatment on clinical cardiovascular outcomes are unknown.

METHODS AND RESULTS

We conducted a randomized, controlled trial in which 66 patients with CHF (29 with and 37 without CSR-CSA) were randomized to either a group that received CPAP nightly or to a control group. Change in left ventricular ejection fraction (LVEF) from baseline to 3 months and the combined mortality-cardiac transplantation rate over the median 2.2-year follow-up period were compared between the CPAP-treated and control groups. For the entire group of patients, CPAP had no significant effect on LVEF, but it was associated with a 60% relative risk reduction (95% confidence interval, 2% to 64%) in mortality-cardiac transplantation rate in patients who complied with CPAP therapy. Stratified analysis of patients with and without CSR-CSA revealed that those with CSR-CSA experienced both a significant improvement in LVEF at 3 months and a relative risk reduction of 81% (95% confidence interval, 26% to 95%) in the mortality-cardiac transplantation rate of those who used CPAP. CPAP had no significant effect on either of these outcomes in patients without CSR-CSA.

CONCLUSIONS

CPAP improves cardiac function in CHF patients with CSR-CSA but not in those without it. Although not definitive, our findings also suggest that CPAP can reduce the combined mortality-cardiac transplantation rate in those CHF patients with CSR-CSA who comply with therapy.

Isolation, genomic organization, and expression analysis of the mouse and rat homologs of MEFV, the gene for familial mediterranean fever

Familial Mediterranean fever (FMF) is a recessive disorder characterized by episodes of fever with serositis or synovitis. Recently the FMF gene (MEFV) was cloned; the protein product, pyrin/marenostrin, is thought to regulate inflammation in myeloid cells. In this manuscript we report the mouse and rat homologs of MEFV. The murine gene contains ten exons with a coding sequence of 2304 bp, while the rat homolog has nine exons with a coding sequence of 2253 bp. A considerable amino acid sequence homology was observed between the mouse and human (47.6% identity and 65.5% similarity) and between the mouse and rat genes (73.5% identity and 82.1% similarity). The predicted rodent proteins have several important domains and signals found in human pyrin, including a B-box zinc finger domain, Robbins-Dingwall nuclear localization signal, and coiled-coil domain. However, perhaps because of an ancient frame-shift mutation, neither the mouse nor the rat protein has an intact C-terminal B30.2 domain, in which most FMF-associated mutations have been found in human MEFV. Nevertheless, like the human gene, mouse Mefv is expressed in peripheral blood granulocytes but not lymphocytes. Consistent with its expression in granulocytes, Mefv was detected at high levels in the primary follicles and marginal zones of the splenic white pulp. Mefv is localized on mouse Chromosome (Chr) 16, region A3-B1, extending a region of synteny with human Chr 16p13.3. Development of knockout and knockin mouse models may provide further insights into the functional evolution of this gene.

Unsaturated aldehydes including 4-OH-nonenal are elevated in patients with congestive heart failure

BACKGROUND

Lipid peroxidation generates several unsaturated aldehydes, such as 4-OH-nonenal (HNE), which may interact with and modify the function of other molecules that are of biological importance. Although congestive heart failure (CHF) is a state of generalized oxidative stress, the resultant spectrum of saturated and unsaturated aldehydes has not been systematically characterized in this condition.

METHODS

We studied 8 CHF patients and 8 age-matched patients with normal left ventricular (LV) function. The concentrations of 22 aldehydes produced by lipid peroxidation, including saturated (n-alkanals) and unsaturated (t-2-alkenals, t-2,t-4-alkadienals, 4-OH-alkenals) aldehydes, were measured in arterial plasma by gas chromatography mass spectrometry (GC/MS). LV contractility (+dP/dt) and relaxation (Tau) were directly measured with a micromanometer-tipped catheter.

RESULTS

Compared with patients who have normal LV function, CHF patients had higher levels of total aldehydes (9,311 +/- 835 v 6,594 +/- 344 nmol/L, P < .01), as well as multiple unsaturated aldehydes (t-2-alkenals and 4-OH-alkenals, including HNE). In the CHF group, a strong relationship was observed between total aldehyde concentration and both +dP/dt (correlation coefficient = -0.76, P < .05) and Tau (correlation coefficient = 0.78, P < .05).

CONCLUSION

Unsaturated aldehyde levels were consistently elevated in the plasma of CHF patients compared with patients who have normal LV function. In CHF patients, elevated aldehyde levels were associated with impairment of LV contractility.

The coxsackie-adenovirus receptor (CAR) is used by reference strains and clinical isolates representing all six serotypes of coxsackievirus group B and by swine vesicular disease virus

Group B coxsackieviruses are etiologically linked to many human diseases, and cell surface receptors are postulated to play an important role in mediating their pathogenesis. The coxsackievirus adenovirus receptor (CAR) has been shown to function as a receptor for selected strains of coxsackievirus group B (CVB) serotypes 3, 4, and 5 and is postulated to serve as a receptor for all six serotypes. In this study, we demonstrate that CAR can serve as a receptor for laboratory reference strains and clinical isolates of all six CVB serotypes. Infection of CHO cells expressing human CAR results in a 1000-fold increase in CVB progeny virus titer compared to mock transfected cells. CAR was shown to be a functional receptor for swine vesicular disease virus (SVDV), as CHO-CAR cells but not CHO mock transfected controls were susceptible to SVDV infection, produced progeny SVDV, and developed cytopathic effects. Moreover, SVDV infection could be specifically blocked by monoclonal antibody to CAR (RmcB). SVDV infection of HeLa cells was also inhibited by an anti-CD55 MAb, suggesting that this virus, like some CVB, may interact with CD55 (decay accelerating factor) in addition to CAR. Finally, pretreatment of CVB or SVDV with soluble CAR effectively blocks virus infection of HeLa cell monolayers.

Repeated hypotensive episodes due to hepatic outflow obstruction during liver transplantation in adult patients

We report two cases of unusual repeated hypotension, decreased cardiac output, decreased mixed venous oxygen saturation, decreased central venous pressure, pulmonary artery pressure, and pulmonary wedge pressure after the completion of all vascular anastamoses of liver transplantation. These unstable hemodynamics appear to reflect a clinically relevant picture of hypovolemia. However, the real cause was partial hepatic outflow obstruction. The obstruction was suspected because hypotension was alleviated by elevating the full-sized liver graft ventrally and to the left. Doppler ultrasound examination confirmed that the flow velocity of the hepatic vein outflow was insufficient when the liver fell to its resting position in the right hepatic fossa. An additional side-to-side cavo-caval anastomosis resolved the problem in one patient, whereas the other required not only the additional anastomosis, but also application of a tissue expander filled with 770 mL normal saline beneath the liver to eliminate the obstruction. We emphasize that obstruction of the hepatic outflow causes only temporal hypovolemia because of a decrease of venous return and that treatment of this complication should be surgical intervention to relieve the obstruction. Blind resuscitation with fluids will not solve the problem and, in fact, may result in fluid overload with subsequent complications.

Cytotoxic aldehyde generation in heart following acute iron-loading

Although the mechanism of myocardial failure following acute iron poisoning is not known, excess iron-catalyzed free radical generation is conjectured to play a role. The effects of time (0 to 360 minutes) on total iron concentrations, glutathione peroxidase activity, and cytotoxic aldehyde production in heart of mice (B6D2F1, n = 65) were first investigated following acute iron-loading (20 mg iron dextran i.p./mouse). In a subsequent experiment, the effects of dose (0 to 80 mg iron dextran i.p./mouse, n = 75) on the aforementioned parameters were investigated. Our results show that the concentrations of cytotoxic aldehydes: (1) significantly differ over-time, with corresponding increases in total concentrations of iron (r = 0.93, p < 0.001); and (2) increase parallel to the total dose of iron administered (r = 0.95, p < 0.001). Furthermore, dose-and time-dependent alterations to glutathione peroxidase activity are observed, which is most likely due to an acute up-regulation of the enzyme as an endogenous protective response to increased free radical activity in the heart subsequent to iron-loading. While no single mechanism is likely to account for the complex pathophysiology of acute iron-induced heart failure, our results shown that iron-loading can result in significant free radical generation, as quantified by cytotoxic aldehydes, in heart tissue of mice. This is the first report on the effects of time and dose on cytotoxic aldehyde generation and glutathione peroxidase activity in heart of mice following acute iron-loading.

Effects of continuous positive airway pressure on cardiac volumes in patients with ischemic and dilated cardiomyopathy

The effects of continuous positive airway pressure (CPAP) on left (LV) and right ventricular (RV) volumes in patients with congestive heart failure (CHF) have not been studied. We hypothesized that CPAP would cause greater reductions in cardiac volumes in CHF patients with idiopathic dilated cardiomyopathy (IDC) than in those with ischemic cardiomyopathy (IsC), because their ventricles are more compliant. The effects of a 30-min CPAP application at 10 cm H(2)O on RV and LV end-diastolic (EDV) and end-systolic volumes (ESV), determined by radionuclide angiography, were therefore tested in 22 patients with CHF due to IsC (n = 13) or IDC (n = 9). CPAP-induced reductions in LVEDV, LVESV, RVEDV, and RVESV were significantly greater (p < 0.05) in the IDC than in the IsC group. Whereas in the IsC group CPAP caused no significant changes in LV or RV volumes, in the IDC group it induced significant reductions in RVEDV (527 +/- 77 ml to 354 +/- 50 ml, p = 0.03) and RVESV (400 +/- 78 ml to 272 +/- 54 ml, p = 0.04) that were greater than any reductions in LVEDV and LVESV. We conclude that CPAP causes greater short-term reductions in RV and LV volumes in CHF patients with IDC than in those with IsC, and that among patients with IDC, CPAP causes greater reductions in RV than in LV volumes.

Oxygen uptake kinetics during exercise in chronic heart failure: influence of peripheral vascular reserve

Exercise performance in chronic heart failure is severely impaired, due in part to a peripherally mediated limitation. In addition to impaired maximal exercise capacity, the O(2) uptake (VO(2)) response during submaximal exercise may be affected, with a greater reliance on anaerobiosis leading to early fatigue. However, the response of VO(2) kinetics to submaximal exercise in chronic heart failure has not been studied extensively; in particular, the relationship between oxygen utilization and the peripheral response to exercise has not been studied. The present investigation examined the time-constant (tau, corresponding to 63% of the total response fitted from exercise onset) of the VO(2) kinetics on-response to submaximal exercise and its relationship to maximal peripheral blood flow in patients with chronic heart failure, and compared responses with those in healthy sedentary subjects. Subjects were 10 patients with chronic heart failure (NYHA class II/III). The mean age was 50+/-12 years, with a mean resting left ventricular ejection fraction of 25+/-9%. Controls were 10 age-matched healthy subjects. VO(2(max)) was first determined for all subjects. Repeated transitions from rest to exercise were performed on a cycle ergometer while measuring breath-by-breath responses of VO(2) at a fixed work rate of 50% of VO(2(max)) (heart failure patients and healthy controls) and at a work rate equivalent to the average in heart failure patients (65 W; healthy controls only). On a separate occasion, post-maximal ischaemic exercise calf blood flow was measured (strain-gauge plethysmography). Whereas heart failure subjects displayed a significantly prolonged VO(2) kinetics response at a similar absolute workload (i.e. 65 W), as indicated by a longer tau value (42 s, compared with 22 s in controls; P<0.01), there was no difference in tau at a similar relative work rate [50% of VO(2(max))]. In addition, heart failure subjects demonstrated a lower maximal calf blood flow (P<0.05) than control subjects. These results indicate that patients with heart failure have a prolonged VO(2) kinetics on-response compared with healthy subjects at a similar absolute work rate (i.e. 65 W), but not at a similar relative work rate [50% of VO(2(max))]. Thus, despite a reduced maximal calf blood flow response associated with heart failure, it does not appear that this contributes to an impairment of the submaximal exercise response beyond that explained by a reduced maximal exercise capacity [VO(2(max))].

A biochemical, histochemical, and electron microscopic study on the effects of iron-loading on the hearts of mice

Acute iron poisoning and chronic iron overload are well-known causes of myocardial failure. Although the exact mechanism is not known, excess iron-catalyzed free radical generation is conjectured to play a role in damaging the myocardium and altering cardiac function. We report here on the effects of acute and chronic iron-loading on the total iron concentration, glutathione peroxidase activity, and cytotoxic aldehyde production in the heart of a murine model (n = 35). Light microscopic examination for the presence of ferrous and ferric iron was undertaken following histochemical staining for these species. In addition, examination of representative samples by transmission electron microscopy was performed. Our findings show that iron-loading can result in significant increases in total iron concentrations, alterations to glutathione peroxidase activity, and increases in cytotoxic aldehyde concentrations in the hearts of mice. Furthermore, we observe that iron-loading can significantly alter and damage various cellular constituents (e.g., mitochondria, lysosomes, sarcoplasmic reticulum) and this may have bearing on the mechanism of iron-induced heart failure.

The complete consensus sequence of coxsackievirus B6 and generation of infectious clones by long RT-PCR

The full length sequence for the human pathogen coxsackievirus B6 (CVB6, Schmitt strain) has been determined. We used long RT-PCR to generate full length DNA amplicon of CVB6, and then directly sequenced the amplicons. One-step cloning of the full length amplicon enabled us to obtain an infectious clone of CVB6. RNA generated from CVB6 amplicon DNA or CVB6 clones, by transcription with T7 RNA polymerase, was demonstrated to be infectious upon transfection into HeLa cells in vitro. The CVB6 genome is characteristic of enteroviruses, with a 5'-non-translated region (743 nucleotides) followed by an open reading frame (encoding a 2184 amino acid polyprotein) and a 3'-non-translated region (100 nucleotides) and polyadenylated tail. The predicted amino acid sequence of CVB6 clustered with the other CVB serotypes and swine vesicular disease virus (SVDV).

Cardiac function and cytotoxic aldehyde production in a murine model of chronic iron-overload

OBJECTIVES

To determine the relationship between the total chronic dose of iron administered, ex-vivo cardiac function and the concentrations of cytotoxic aldehydes in heart tissue of a murine model.

METHODS

In the first experiment, 34 male B6D2F1 mice were randomized to receive intraperitoneal injections of 5, 10 or 20 mg of iron dextran for three weeks, or a placebo control. The mice were subsequently randomized to undergo ex-vivo assessment of cardiac function. In the second experiment, free radical generation, quantified by the presence of 20 separate cytotoxic aldehydes, was assessed in heart tissue of 40 mice that were randomized to receive chronic treatment with various concentrations of iron dextran (100 mg to 300 mg total chronic dose administered), placebo treatment with saline, or no treatment at all (baseline).

RESULTS

Iron-loaded groups displayed dose-dependent depressions of heart rate, systolic pressure, developed pressure, coronary pressure, -dP/dt and +dP/dt, and increases in diastolic pressure. Monotonic dose-dependent increases in total heart aldehydes were observed in the iron-treated groups (r-0.97, p < 0.0001), whereas no significant differences were observed between baseline or time-placebo control groups.

CONCLUSIONS

While no single mechanism is likely to account for the complex pathophysiology of iron-induced heart failure, our findings show that chronic iron-loading in a murine model results in dose-dependent alterations to cardiac function; and results in free radical mediated damage to the heart, as measured by excess concentrations of cytotoxic aldehyde-derived peroxidation products. This is the first description of the effects of excess iron on cardiac function assessed by an ex-vivo Langendorff technique in a murine model of chronic iron-overload.

Potential role of the microvasculature in progression of heart failure

After cardiac injury, there are changes in the cardiac myocyte morphology, function, matrix, and molecular gene expression. These all play an important role in remodeling of the injured heart, contributing to the progression toward heart failure. The role of the microvasculature in the progression toward heart failure is less well characterized. However, laboratory studies have established that there are important interactions between the microvascular endothelium and the myocyte. Furthermore, in a multitude of animal models of heart failure and cardiomyopathy, there is always an association with microvascular abnormalities. Reversal of these abnormalities is also associated with improvement in the cardiomyopathy. Major mediators that likely play an important role in the microvasculature include endothelin and nitric oxide. These are elaborated by both endothelium and myocyte compartments of the myocardium. Preliminary clinical studies already demonstrate that microvascular ischemia may have prognostic power in patients with nonischemic dilated cardiomyopathy. Results from these studies showed a reduction in mortality from treatment with amlodipine, suggesting a possible benefit based on changes in the microvasculature.

Modulation of iron uptake in heart by L-type Ca2+ channel modifiers: possible implications in iron overload

Heart failure is the leading cause of mortality in patients with transfusional iron (Fe) overload in which myocardial iron uptake ensues via a transferrin-independent process. We examined the ability of L-type Ca2+ channel modifiers to alter Fe2+ uptake by isolated rat hearts and ventricular myocytes. Perfusion of rat hearts with 100 nmol/L 59Fe2+ and 5 mmol/L ascorbate resulted in specific 59Fe2+ uptake of 20.4+/-1.9 ng of Fe per gram dry wt. Abolishing myocardial electrical excitability with 20 mmol/L KCl reduced specific 59Fe2+ uptake by 60+/-7% (P<0.01), which suggested that a component of myocardial Fe2+ uptake depends on membrane voltage. Accordingly, 59Fe2+ uptake was inhibited by 10 micromol/L nifedipine (45+/-12%, P<0.02) and 100 micromol/L Cd2+ (86+/-3%; P<0. 001) while being augmented by 100 nmol/L Bay K 8644 (61+/-18%, P<0. 01) or 100 nmol/L isoproterenol (40+/-12%, P<0.05). By contrast, uptake of 100 nmol/L ferric iron (59Fe3+) was significantly lower (1. 4+/-0.3 ng Fe per gram dry wt; P<0.001) compared with divalent iron. These data suggest that a component of Fe2+ uptake into heart occurs via the L-type Ca2+ channel in myocytes. To investigate this further, the effects of Fe2+ on cardiac myocyte L-type Ca2+ currents were measured. In the absence of Ca2+, noninactivating nitrendipine-sensitive Fe2+ currents were recorded with 15 mmol/L [Fe2+]o. Low concentrations of Fe2+ enhanced Ca2+ current amplitude and slowed inactivation rates, which was consistent with Fe2+ entry into the cell, whereas higher Fe2+ levels caused dose-dependent decreases in peak current. Fe3+ had no effect on current amplitude or decay. Combined, our data suggest that myocardial Fe2+ uptake occurs via L-type Ca2+ channels and that blockade of these channels might be useful in the treatment of patients with excessive serum iron levels.