Effect of heat shock protein 47 on collagen accumulation in keloid fibroblast cells

BACKGROUND

Keloid is characterized by excessive collagen accumulation, but the mechanism of keloid formation remains unknown, and none of the treatment modalities are consistently effective. Heat shock protein (HSP) 47, known as a collagen-specific molecular chaperone, plays a critical role in collagen biosynthesis. Our previous research has demonstrated that HSP47 is highly expressed in keloid compared with normal skin tissues, which indicates that there might be a close relationship between overexpression of HSP47 and excessive collagen accumulation in keloid formation.

OBJECTIVES

To further investigate whether overexpression of HSP47 might promote excessive collagen deposition in keloid formation, we examined the alteration of intracellular and extracellular collagen expression, following inhibition of HSP47 expression in keloid fibroblast cells by the RNA interference technique.

METHODS

Three constructed psiRNA-hH1neo plasmids, carrying three pairs of related HSP47-shRNA (small hairpin RNA), respectively, were transfected into keloid fibroblast cells and compared with three control groups. After transfection, the mRNA and protein expression of HSP47 and collagen type I were detected by quantitative real-time polymerase chain reaction and Western blot; the content of extracellular secreting collagen was assessed by hydroxyproline assay; and the MTT [3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide] method was adopted to examine the proliferation of keloid fibroblast cells.

RESULTS

Both the mRNA and protein levels of HSP47 in keloid fibroblast cells decreased dramatically 48 h after post-transfection of three related HSP47-shRNA plasmids, compared with control groups. Following the downregulation of HSP47, we found that the expression of intracellular and extracellular collagen was correspondingly reduced. On the other hand, the MTT assay showed that transfection of HSP47-shRNA plasmids did not influence the growth of keloid fibroblast cells.

CONCLUSIONS

Combined with our previous histological results, we propose that overexpression of HSP47 in keloid fibroblast cells could induce excessive collagen accumulation by enhancing synthesis and secretion of collagen, which not only presents a possible mechanism of keloid formation, but also offers a therapeutic potential of RNA interference to HSP47 for the treatment of keloid and other fibroproliferative disorders.

Occurrence of Rust Caused by Puccinia carthami on Snow Lotus in China

Snow lotus (Saussurea involucrata (Kar. & Kir.) Sch. Bip.) is an economically important medicinal herb increasingly grown in China in recent years. In August 2005, a rust disease on snow lotus plants commercially grown was found in the Tianshan mountain area of Xinjiang at 2,100 m above sea level. Disease incidence was approximately 15% of the plants observed in a commercial field in 2006. At the initial stage, tiny (1 to 2 mm long), orange brown pustules are formed on leaves. Later in the season, pustules turned chestnut brown to form bigger rust patches. Severely attacked leaves may die prematurely. During the growing season, rust pustules broke open to release reddish brown spores that cause secondary infection. The infected snow lotus plants were sampled, and the urediniospores and teliospores were observed for identification with a light microscope (4). Urediniospores were globose or broadly ellipsoid, 22 to 28 × 22 to 25 μm; teliospores were slightly or not constricted at the septum, 31.5 to 41.5 × 21.5 to 26.5 μm, wall was sienna to fulvous, occasionally chestnut colored, and pedicels were basal or oblique, verrucose, hyaline, and fragile. The pathogenicity test of the fungus was done by burying five leaves bearing telia around the roots of healthy safflower seedlings grown in a greenhouse under controlled conditions (25°C and 70% relative humidity) and healthy snow lotus seedlings grown under natural conditions with five replications. Symptoms were evaluated 60 days after inoculation. Similar rust symptoms were observed on both the snow lotus and safflower seedlings (1). The pycnidial and aecial stages of this autoecious rust were not observed in nature or the pathogenicity tests. The teliospores were reisolated and deposited at the Key Oasis Eco-Agriculture Laboratory of Xinjiang Production and Construction Group, Xinjiang and the Institute of Biotechnology, Zhejiang University. The causal organism of rust of snow lotus was identified as Puccinia carthami Corda on the basis of the morphology and pathogenicity test. To our knowledge, this is the first report of this rust on snow lotus (S. involucrata) (1-4). References: (1) W. L. Bruckart. Plant Dis. 83:181, 1999. (2) M. L. Deadman et al. Plant Dis. 89:208, 2005. (3) S. J. Kolte. Diseases of annual edible oilseeds crops. In: Rapeseed-Mustard and Sesame Diseases. Vol. II. CRC Press, Boca Raton, FL, 1985. (4) G. F. Laundon. N. Z. J. Bot. 8:310, 1970.

Hepatic lipogenesis in broiler chickens with different fat deposition during embryonic development

In order to identify the genes involved in the fatness variability, we studied the expression of several genes implicated in the hepatic lipid metabolism of broiler chickens with different fat deposition patterns during embryonic development. The mRNA expression of acetyl CoA carboxylase (ACC), fatty acid synthase (FAS), malic enzyme (ME) and apolipoprotein B100 (apoB100) genes were determined using reverse transcriptase-polymerase chain reaction (RT-PCR). Samples of livers were collected from Arbor Acres (AA) and Sanhuang (SH) chickens on day 9, 14 and 19 of embryonic development as well as at hatching. This study showed that hepatic triglyceride (TG) level was found to increase suddenly during day 14 of embryonic development, to gradually increase thereafter, and to remain relatively constant at hatching. FAS gene expression in AA and SH broilers occurred prior to hatching and at hatching. The gene was expressed more in the former breed. ACC gene expression was observed beginning at the earlier development stage of days 9. No breed difference was observed in ME and apoB gene expression. This study indicated that the expression of lipogenic enzyme genes of the liver in broiler chickens exhibited scheduling during embryogenesis. The ACC gene started to express earlier than the FAS gene during embryonic development. This suggested that embryonic liver synthesized fatty acid, and breed difference was noticed prior to hatching.

A double tyrosine phosphorylation of P68 RNA helicase confers resistance to TRAIL-induced apoptosis

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising anticancer agent with the capability of inducing apoptosis specifically in tumor cells. However, cancer cells of many cancer types developed TRAIL resistance, limiting the applications of TRAIL in cancer therapies. We show here that p68 acquires a double tyrosine phosphorylation at Y593 and Y595 in TRAIL-resistant T98G glioblastoma cells. The double phosphorylations are induced by platelet-derived growth factor autocrine loop. The double phosphorylation mediates resistance to TRAIL-induced apoptosis. Our data suggest that the phosphorylated p68 protects the cells from programmed cell death by preventing procaspase-8 from proteolytic cleavage. The double-phosphorylated p68 may also confer apoptosis resistance by upregulation of X-chromosome-linked inhibitor apoptosis protein-associated factor 1. In addition, exogenous expression of p68 mutant that carries mutations at the phosphorylation sites (Y593/595F) dramatically sensitizes TRAIL-resistant cells to TRAIL-induced apoptosis, suggesting a potential therapeutic strategy to overcome TRAIL resistance.

Selective imaging of adherent targeted ultrasound contrast agents

The goal of ultrasonic molecular imaging is the detection of targeted contrast agents bound to receptors on endothelial cells. We propose imaging methods that can distinguish adherent microbubbles from tissue and from freely circulating microbubbles, each of which would otherwise obscure signal from molecularly targeted adherent agents. The methods are based on a harmonic signal model of the returned echoes over a train of pulses. The first method utilizes an 'image-push-image' pulse sequence where adhesion of contrast agents is rapidly promoted by acoustic radiation force and the presence of adherent agents is detected by the signal change due to targeted microbubble adhesion. The second method rejects tissue echoes using a spectral high-pass filter. Free agent signal is suppressed by a pulse-to-pulse low-pass filter in both methods. An overlay of the adherent and/or flowing contrast agents on B-mode images can be readily created for anatomical reference. Contrast-to-tissue ratios from adherent microbubbles exceeding 30 dB and 20 dB were achieved for the two methods proposed, respectively. The performance of these algorithms is compared, emphasizing the significance and potential applications in ultrasonic molecular imaging.

Genetics of antimicrobial resistance

Antimicrobial resistant strains of bacteria are an increasing threat to animal and human health. Resistance mechanisms to circumvent the toxic action of antimicrobials have been identified and described for all known antimicrobials currently available for clinical use in human and veterinary medicine. Acquired bacterial antibiotic resistance can result from the mutation of normal cellular genes, the acquisition of foreign resistance genes, or a combination of these two mechanisms. The most common resistance mechanisms employed by bacteria include enzymatic degradation or alteration of the antimicrobial, mutation in the antimicrobial target site, decreased cell wall permeability to antimicrobials, and active efflux of the antimicrobial across the cell membrane. The spread of mobile genetic elements such as plasmids, transposons, and integrons has greatly contributed to the rapid dissemination of antimicrobial resistance among several bacterial genera of human and veterinary importance. Antimicrobial resistance genes have been shown to accumulate on mobile elements, leading to a situation where multidrug resistance phenotypes can be transferred to a susceptible recipient via a single genetic event. The increasing prevalence of antimicrobial resistant bacterial pathogens has severe implications for the future treatment and prevention of infectious diseases in both animals and humans. The versatility with which bacteria adapt to their environment and exchange DNA between different genera highlights the need to implement effective antimicrobial stewardship and infection control programs in both human and veterinary medicine.

Statistical study of effective anisotropy field in ordered ferromagnetic nanowire arrays

Soft ferromagnetic nanowire arrays were obtained by electrodeposition of Co-Fe-P alloy into the pores of high quality home-made anodized aluminum oxide (AAO) templates. Bath acidity and current density were the two parameters used in order to tailor the orientation of local anisotropy axes in individual nanowires. In order to quantify the influence of the induced anisotropies on the magnetization processes in individual nanowires, the in-plane magnetization loops of the arrays are modeled as log-normal distributions of Stoner-Wohlfarth transverse magnetization processes. Using the lognormal mean parameter as an approximation for the saturation applied field of the array, we compute the effective anisotropy of the nanowires, which is found to increase with the pH of the electrodeposition bath.

Functional reconstruction of maxilla with pedicled buccal fat pad flap, prefabricated titanium mesh and autologous bone grafts

The aim of this study was to evaluate the use of pedicled buccal fat pad flap (PBFPF), prefabricated titanium mesh and autologous bone graft in maxillary reconstruction. Seventeen patients with a unilateral class I-III maxillary defect were involved. Preoperatively, a solid model was manufactured based on virtual maxillectomy and reconstruction of the abnormal maxilla. Intraoperatively, PBFPF was applied to repair the soft-tissue defect, serving as nasal lining and the receiving bed for bone grafts. Titanium mesh was prefabricated on the solid model and then, together with bone grafts from iliac crest, fixed to residual bones to reconstruct the hard-tissue defect. Postoperative aesthetic appearance and function were followed up. No exposure of titanium mesh, leakage or oronasal regurgitation occurred. Of the patients with a class I or II defect 91% (10/11) and of those with a class III defect 50% (3/6) gained a good appearance. Fifteen patients were articulate. Eleven patients received dental rehabilitation and had a normal diet. PBFPF with prefabricated titanium mesh and autologous bone grafts is a reliable option for reconstruction of unilateral maxillary defects of class I and II, but this method alone should be used cautiously in defects of class III and beyond.

Comparison of multilocus sequence typing, pulsed-field gel electrophoresis, and antimicrobial susceptibility typing for characterization of Salmonella enterica serotype Newport isolates

In the United States, multidrug-resistant phenotypes of Salmonella enterica serotype Newport (commonly referred to as MDR-AmpC) have emerged in animals and humans and have become a major public health problem. Although pulsed-field gel electrophoresis (PFGE) is the current "gold standard" typing method for Salmonella, multilocus sequence typing (MLST) may be more relevant to investigations exploring evolutionary and population biology relationships. In this study, 81 Salmonella enterica serotype Newport isolates from humans, food animals, and retail foods were examined for antimicrobial susceptibility and characterized using PFGE and MLST of seven genes, aroC, dnaN, hemD, hisD, purE, sucA, and thrA. Forty-nine percent of the isolates were resistant to nine or more of the tested antimicrobials. Salmonella isolates displayed resistance most often to sulfamethoxazole (57%), streptomycin (56%), tetracycline (56%), ampicillin (52%), and ceftiofur (49%) and, to a lesser extent, to kanamycin (19%), trimethoprim-sulfamethoxazole (17%), and gentamicin (11%). A total of 43 PFGE patterns were generated using XbaI, indicating a genetically diverse population. The largest PFGE cluster contained isolates from clinically ill swine, cattle, and humans. MLST resulted in 12 sequence types (STs), with one type encompassing 62% of the strains. Ten new sequence types and one novel allele type were identified. Furthermore, MLST typing showed that strains closely related by PFGE clustered in major STs, whereas more distantly related strains were separated into two clusters by PFGE. The results of this study demonstrated that the MLST scheme employed here clustered S. enterica serovar Newport isolates in distinct molecular populations, and strain discrimination was enhanced by combining PFGE, antimicrobial susceptibility, and MLST results.

Armored RNA as positive control and standard for quantitative reverse transcription-polymerase chain reaction assay for rubella virus

RV Armored RNA constructed in the laboratory was shown to be resistant to RNase and DNase digestion. It could remain stable at 4 degrees C for at least 60 days, and was much more stable than RV strain TR23 [corrected] in normal human plasma. Therefore it could be used as stable, well-characterized positive control and standard for quantitative RT-PCR assay.

Transcatheter closure of patent ductus arteriosus with severe pulmonary arterial hypertension in adults

BACKGROUND

Surgical closure of patent ductus arteriosus (PDA) with severe pulmonary arterial hypertension in adults carries higher risk than in children.

OBJECTIVES

To investigate the application of self-expandable occluders for transcatheter closure of PDA associated with severe pulmonary arterial hypertension in adults, and the assessment of immediate and short-term results.

METHODS

29 adult patients (6 men, 23 women) underwent attempted transcatheter closure of PDA at a mean (standard deviation (SD)) age of 31.1 (11.4) years (range 18-58 years) and a mean (SD) weight of 54.1 (7.1) kg (range 42-71 kg). On the basis of haemodynamic and clinical data obtained before and after trial occlusion, the final duct occlusion was determined and carried out. Radiographs of the chest, electrocardiograms and echocardiograms were used for follow-up evaluation of the treatment within 1 day, 1 month and 3-6 months after successful closure.

RESULTS

20 of the 29 patients had successful occlusion (group 1), and 9 patients failed (named group 2). In group 1, in which occlusion was successful, mean (SD) pulmonary arterial pressures decreased markedly after trial occlusion: 78 (19.3) mm Hg (range 50-125 mm Hg) before occlusion and 41 (13.8) mm Hg (range 23-77 mm Hg) after occlusion. Systemic arterial oxygen saturation was found to be >90% in 19 patients and <90% in the remaining patient before inhalation of oxygen, and >95% during inhalation of oxygen or after occlusion in all 20 patients. In group 2, the occlusion was not successful, because in two patients the device was not available; another two patients showed worsening of symptoms. The other five patients showed increased pulmonary arterial pressures after trial closure; their mean (SD) pulmonary arterial pressures increased by 10.3 (6) mm Hg (4-16 mm Hg) after trial occlusion, and systemic arterial oxygen saturation was 85.5% (2.6%) (range 82.6-88%) before inhalation of oxygen and 94.7% (1.7%) (range 90.7-99.1%) during inhalation of oxygen. In group 1, the dimensions of the left atrium, left ventricle and pulmonary artery increased considerably in 3-6-months of follow-up compared with those of preocclusion.

CONCLUSIONS

Transcatheter closure is an effective treatment for adults with PDA associated with reversible severe pulmonary arterial hypertension. Further research is needed for the evaluation of long-term results.

Nucleostemin mRNA is expressed in both normal and malignant renal tissues

Nucleostemin (NS), a p53-binding protein, has been shown essential for stem and cancer cell proliferation and implicated in oncogenesis. To explore potential contributions of NS to the development of clear cell renal cell carcinomas (ccRCCs), we determined NS expression in ccRCC cell lines, and in paired normal and malignant renal tissues from 31 patients with ccRCC. Nucleostemin mRNA and/or protein expression was observed in all four cell lines and 27 of 31 (87%) tumour specimens. Surprisingly, 16 of 31 (52%) adjacent normal renal samples also expressed NS mRNA and its levels in four of them were comparable with those in paired tumour tissues. Three of the patients had detectable NS mRNA in their normal renal tissues whereas lacked its expression in the matched tumours. Compared to the oncogene c-MYC expression in these same samples, NS expression showed a much less specificity for ccRCC. We further demonstrated that NS mRNA expression was closely associated with cellular proliferation in normal fibroblasts or T lymphocytes and renal cell carcinoma cell lines. Collectively, NS expression widely occurs in normal and malignant renal tissues, and is likely a proliferation marker rather than a unique regulator of cell proliferation and survival in stem and cancer cells.

Intelligent compensation of friction, ripple, and hysteresis via a regulated chatter

In this paper, a hybrid control scheme utilizing a PID feedback control with an additional regulated chatter signal is developed to compensate motion impeding influences such as the effects due to friction, force ripples, and hysteresis in linear piezoelectric motor. The regulated chatter signal is a pulse sequence superimposed on the PID control signal. It has a fixed amplitude, and a pulse width regulated via iterative learning control. As such, the scheme is expected to be useful for applications involving iterative motion sequences. An analysis of the closed-loop performance is presented in the paper. Simulation and experimental results are also furnished to demonstrate that the proposed control scheme can reduce tracking errors significantly.

Antimicrobial resistance and genetic relatedness among Salmonella from retail foods of animal origin: NARMS retail meat surveillance

Salmonella isolates were recovered from a monthly sampling of chicken breasts, ground turkey, ground beef, and pork chops purchased from selected grocery stores in six participating FoodNet sites (Connecticut, Georgia, Maryland, Minnesota, Oregon, and Tennessee) in 2002 and an additional two sites in 2003 (California and New York). In 2002 and 2003, a total of 6,046 retail meats were examined, including 1,513 chicken breasts, 1,499 ground turkey samples, 1,522 ground beef samples, and 1,502 pork chops. Retail meat samples tested increased to 3,533 in 2003 as compared to 2,513 in 2002. Overall, six percent of 6,046 retail meat samples (n = 365) were contaminated with Salmonella, the bulk recovered from either ground turkey (52%) or chicken breast (39%). Salmonella isolates were serotyped and susceptibility tested using a panel of 16 antimicrobial agents. S. Heidelberg was the predominant serotype identified (23%), followed by S. Saintpaul (12%), S. Typhimurium (11%), and S. Kentucky (10%). Overall, resistance was most often observed to tetracycline (40%), streptomycin (37%), ampicillin (26%), and sulfamethoxazole (25%). Twelve percent of isolates were resistant to cefoxitin and ceftiofur, though only one isolate was resistant to ceftriaxone. All isolates were susceptible to amikacin and ciprofloxacin; however, 3% of isolates were resistant to nalidixic acid and were almost exclusive to ground turkey samples (n = 11/12). All Salmonella isolates were analyzed for genetic relatedness using pulsed-field gel electrophoresis (PFGE) patterns generated by digestion with Xba1 or Xba1 plus Bln1. PFGE fingerprinting profiles showed that Salmonella, in general, were genetically diverse with a total of 175 Xba1 PFGE profiles generated from the 365 isolates. PFGE profiles showed good correlation with serotypes and in some instances, antimicrobial resistance profiles. Results demonstrated a varied spectrum of antimicrobial resistance and PFGE patterns, including several multidrug resistant clonal groups among Salmonella isolates, and signify the importance of sustained surveillance of foodborne pathogens in retail meats.

Differential regulation of five Pht1 phosphate transporters from maize (Zea mays L.)

Maize is one of the most important crops in the developing world, where adverse soil conditions and low fertilizer input are the two main constraints for stable food supply. Understanding the molecular and biochemical mechanisms involved in nutrient uptake is expected to support the development of future breeding strategies aimed at improving maize productivity on infertile soils. Phosphorus is the least mobile macronutrient in the soils and it is often limiting plant growth. In this work, five genes encoding Pht1 phosphate transporters which contribute to phosphate uptake and allocation in maize were identified. In phosphate-starved plants, transcripts of most of the five transporters were present in roots and leaves. Independent of the phosphate supply, expression of two genes was predominant in pollen or in roots colonized by symbiotic mycorrhizal fungi, respectively. Interestingly, high transcript levels of the mycorrhiza-inducible gene were also detectable in leaves of phosphate-starved plants. Thus, differential expression of Pht1 phosphate transporters in maize suggests involvement of the encoded proteins in diverse processes, including phosphate uptake from soil and transport at the symbiotic interface in mycorrhizas, phosphate (re)translocation in the shoot, and phosphate uptake during pollen tube growth.

Characterization of antimicrobial-resistant Salmonella isolated from imported foods

Two-hundred eight Salmonella isolates recovered from over 5,000 imported foods entering the United States in 2001 were tested for antimicrobial susceptibilities and further characterized for quinolone resistance mechanisms, integron carriage, and genetic relatedness. Salmonella Weltevreden (20%), Salmonella Newport (6%), Salmonella Lexington (5%), and Salmonella Thompson (4%) were the four most common serotypes recovered. Twenty-three (11%) isolates were resistant to at least one antimicrobial, and seven (3.4%) to three or more antimicrobials. Resistance was most often observed to tetracycline (9%), followed by sulfamethoxazole (5%), streptomycin (4%), nalidixic acid (3%), and trimethoprim/sulfamethoxazole (2%). One Salmonella Schwarzengrund isolate recovered from squid imported from Taiwan exhibited resistance to eight antimicrobials, including ampicillin, chloramphenicol, gentamicin, kanamycin, nalidixic acid, sulfamethoxazole, tetracycline, and trimethoprim/sulfamethoxazole. Six isolates (Salmonella Bareilly, Salmonella Derby, Salmonella Ohio and three Salmonella Schwarzengrund) contained class 1 integrons, which carried several resistance genes including dhfrI/dhfrXII, aadA, pse-1, and sat1, conferring resistance to trimethoprim/sulfamethoxazole, streptomycin, ampicillin, and streptothricin, respectively. Five of six nalidixic acid-resistant isolates possessed DNA point mutations at either Ser83 or Asp87 in DNA gyrase. One ciprofloxacin-resistant isolate possessed double mutations in DNA gyrase at positions Ser83 and Asp87 as well as a single mutation at Ser80 in parC. The top three serotypes identified, Salmonella Weltevreden (n = 41), Salmonella Newport (n = 13), and Salmonella Lexington (n = 11), were further characterized for genetic relatedness by pulsed-field gel electrophoresis. Fifty-five distinct pulsed-field gel electrophoresis patterns were observed among the 65 isolates, indicating extensive genetic diversity among these Salmonella serotypes contaminating imported foods.

Genotyping of Campylobacter spp. from retail meats by pulsed-field gel electrophoresis and ribotyping

AIMS

To determine the genetic relatedness of Campylobacter spp. from retail meat products, and compare the discriminatory power of pulsed-field gel electrophoresis (PFGE) and automatic ribotyping.

METHODS AND RESULTS

A total of 378 Campylobacter isolates recovered from 159 raw meats (130 chicken, 25 turkey, three pork and one beef) sampled from 50 retail grocery stores of four supermarket chains in the Maryland suburban area from August 1999 to July 2000 were analysed by PFGE with SmaI, 120 isolates of which were also characterized by ribotyping with PstI using RiboPrinter system. A total of 148 unique PFGE patterns were identified, 91 of which were present in multiple Campylobacter isolates and 24 in multiple meat samples. Nineteen Campylobacter clones with identical PFGE patterns recurred frequently (up to nine times) throughout the sampling period. Comparing ribotyping with PFGE, we identified 44 PFGE patterns and 22 RiboGroups among the 120 isolates tested. Multiple PFGE patterns within one RiboGroup were commonly observed, as well as multiple RiboGroups within one PFGE pattern.

CONCLUSIONS

Although Campylobacter present in retail meats were genetically diverse, certain clones persisted in poultry meats. PFGE had a greater discriminatory power than ribotyping, and the two methods were complementary in genotyping Campylobacter.

SIGNIFICANCE AND IMPACT OF THE STUDY

Genomic DNA fingerprinting of Campylobacter confirmed diverse and recurrent Campylobacter clones in the retail meats, which provides additional data for a better understanding of the epidemiological aspect of Campylobacter infection.

Insertion mutation at the C-terminus of the serotonin transporter disrupts brain serotonin function and emotion-related behaviors in mice

The 5-hydroxytryptamine transporter (5-HTT) regulates 5-hydroxytryptamine (5-HT) neurotransmission by removing 5-HT from the synaptic cleft. Emerging evidence from clinical and genetic studies implicates the 5-HTT in various neuropsychiatric conditions, including anxiety and depression. Here we report that a 5-HTT null mutant mouse line was generated by gene trapping that disrupted the sequence encoding the C-terminus of 5-HTT. This mutation resulted in significant reduction of 5-HTT mRNA and loss of 5-HTT protein. Brain levels of 5-HT and its major metabolite, 5-hydroxyindoleacetic acid, were markedly decreased in C-terminus 5-HTT -/- mice, while 5-HT uptake or 5-HT content in platelets was absent. Behavioral phenotyping showed that C-terminus 5-HTT -/- mice were normal on a screen for gross behavioral, neurological, and sensory functions. In the tail suspension test for depression-related behavior, C-terminus 5-HTT -/- mice showed increased immobility relative to their +/+ controls. By comparison, a previously generated line of 5-HTT -/- mice lacking exon 2, encoding the N-terminus of the 5-HTT, showed abnormally high immobility in response to repeated, but not acute, exposure to the tail suspension test. In a novel, brightly-lit open field, both C-terminus 5-HTT -/- mice and N-terminus 5-HTT -/- mice displayed decreased center time and reduced locomotor activity compared with their +/+ controls. Both mutant lines buried significantly fewer marbles than their +/+ controls in the marble burying test. These findings further demonstrate the neurobiological functions of the 5-HTT and add to a growing literature linking genetic variation in 5-HTT function with emotional abnormalities.

Transcriptional responses to ionizing radiation reveal that p53R2 protects against radiation-induced mutagenesis in human lymphoblastoid cells

The p53 protein has been implicated in multiple cellular responses related to DNA damage. Alterations in any of these cellular responses could be related to increased genomic instability. Our previous study has shown that mutations in p53 lead to hypermutability to ionizing radiation. To investigate further how p53 is involved in regulating mutational processes, we used 8K cDNA microarrays to compare the patterns of gene expression among three closely related human cell lines with different p53 status including TK6 (wild-type p53), NH32 (p53-null), and WTK1 (mutant p53). Total RNA samples were collected at 1, 3, 6, 9, and 24 h after 10 Gy gamma-irradiation. Template-based clustering analysis of the gene expression over the time course showed that 464 genes are either up or downregulated by at least twofold following radiation treatment. In addition, cluster analyses of gene expression profiles among these three cell lines revealed distinct patterns. In TK6, 165 genes were upregulated, while 36 genes were downregulated. In contrast, in WTK1 75 genes were upregulated and 12 genes were downregulated. In NH32, only 54 genes were upregulated. Furthermore, we found several genes associated with DNA repair namely p53R2, DDB2, XPC, PCNA, BTG2, and MSH2 that were highly induced in TK6 compared to WTK1 and NH32. p53R2, which is regulated by the tumor suppressor p53, is a small subunit of ribonucleotide reductase. To determine whether it is involved in radiation-induced mutagenesis, p53R2 protein was inhibited by siRNA in TK6 cells and followed by 2 Gy radiation. The background mutation frequencies at the TK locus of siRNA-transfected TK6 cells were about three times higher than those seen in TK6 cells. The mutation frequencies of siRNA-transfected TK6 cells after 2 Gy radiation were significantly higher than the irradiated TK6 cells without p53R2 knock down. These results indicate that p53R2 was induced by p53 protein and is involved in protecting against radiation-induced mutagenesis.

A study of neonatal swimming (water therapy) applied in clinical obstetrics

OBJECTIVE

To study the significance of some clinical parameters related to neonatal 'swimming' (water therapy) during hospitalization.

METHODS

Normal newborns were randomly divided into two groups to observe their birth weight, weight before discharge,time of first defecation and meconium turning yellow. Group one was the swimming (study) group, comprising a total of 223 newborns including 127 babies delivered after spontaneous vaginal delivery and 96 babies after Cesarean section. Group two was the bathing (control) group, comprising 154 newborns including 109 babies delivered after spontaneous vaginal delivery and 45 babies after Cesarean section.

RESULTS

There was no significant difference in birth weight between the two groups (p > 0.05). However, the mean weight before discharge of the babies in the study group was 3.29 + 0.35 and 3.51 + 0.40 kg, spontaneous vaginal delivery vs. Cesarean section, compared with 3.09 + 0.38 and 3.17 + 0.48 kg, respectively, in the control group (p < 0.01). The corresponding mean times of meconium turning yellow were 39.15 + 15.88 and 39.02 + 13.60 h in the study group compared with 48.01 + 19.42 and 55.67 + 25.05 h in the control group. This difference was significant (p < 0.01), as was the difference between the time of first defecation (p < 0.05).

CONCLUSION

Neonatal swimming can accelerate babies' growth in the early stage.

Characterization of Salmonella Typhimurium of Animal Origin Obtained from the National Antimicrobial Resistance Monitoring System

Salmonella Typhimurium remains one of the most common causes of salmonellosis in animals and humans in the United States. The emergence of multi-drug resistant Salmonella reduces the therapeutic options in cases of invasive infections, and has been shown to be associated with an increased burden of illness. In this study, 588 S. Typhimurium (including var. Copenhagen) isolates obtained from either animal diagnostic specimens (n = 199) or food animals after slaughter/processing (n = 389) were examined for antimicrobial susceptibility, presence of class-1 integrons, and characterized using pulsed-field gel electrophoresis and phage typing. Seventy-six percent (448/588) of isolates were resistant to at least one antimicrobial. Salmonella isolates displayed resistance most often to streptomycin (63%), tetracycline (61%), ampicillin (61%), and to a lesser extent, chloramphenicol (36%), ceftiofur (15%), gentamicin (9%), and nalidixic acid (4%), with more resistance observed among diagnostic isolates. Salmonella recovered from turkeys (n = 38) exhibited the highest rates of resistance, with 92% of isolates resistant to least one antimicrobial, and 58% resistant to > or =10 antimicrobials. Class 1 integrons were present in 51% of all isolates. Five integron associated resistance genes (aadA, aadB, pse-1, oxa-2 and dhfr) were identified. A total of 311 PFGE patterns were generated using XbaI, indicating a genetically diverse population. The largest PFGE cluster contained 146 isolates, including DT104 isolates obtained from all seven animal species. Results demonstrated a varied spectrum of antimicrobial resistance, including several multidrug resistant clonal groups, among S. Typhimurium and S. Typhimurium var. Copenhagen isolates recovered from both diagnostic and slaughter/processing samples.

First Report of Phoma exigua as a Pathogen of Salal (Gaultheria shallon) in British Columbia, Canada

Salal (Gaultheria shallon Pursh.) is an ericaceous, evergreen, and rhizomatous shrub that competes for nutrients and moisture with young conifers in low elevation, coastal British Columbia (BC). A survey was conducted on southern Vancouver Island, BC during the summer of 1999 to find fungal pathogens of salal that might serve as biocontrol organisms (3). Phoma exigua Desmaz. (isolate PFC2705) near Parksville, BC proved to be pathogenic on salal. Identification of PFC2705 at the Centraalbureau voor Schimmelcultures was based on morphology and ITS sequences (GenBank Accession No. AY927784). Pathogenicity was determined with 24 salal seedlings (3-month-old) by inoculating with mycelial suspensions (20% v/v) or conidial suspensions (1 × 10⁶ conidia per ml in 0.5% potato dextrose broth). Inoculated seedlings were placed in plastic bags and incubated in a greenhouse (16 to 23°C with natural light). Plastic bags were removed after 2 days. Initial disease symptoms were observed 2 days after inoculation. Brown, sunken lesions appeared on the surface of young leaves and stems and extended quickly. All seedlings were killed within 14 days. Twelve control plants showed no disease symptoms. With diseased salal leaves incubated at 23°C with 12-h fluorescent light/dark and 100% relative humidity, pycnidia appeared on leaf surfaces within 5 days. Conidia were hyaline, ellipsoid, one-celled, sometimes two- to three-celled, 2.5 to 3.8 × 5 to 12.5 μm, with a rounded base; the colony was gray or dark gray on potato dextrose agar after 5 to 7 days. Reisolation from the inoculated diseased leaves produced a mycelial colony that shared the same growth and morphological characteristics as the initial isolate. Phyllosticta gaultheriae Ellis & Everh., a widely reported foliar pathogen of salal, is distinct morphologically from P. exigua (1). To our knowledge, this is the first report of P. exigua as a pathogen of salal in Canada (2). A voucher specimen has been deposited at the Pacific Forestry Center Herbarium (DAVFP No. 28735). References: (1) J. Bissett and S. J. Darbyshire. No. 275 in: Fungi Canadenses, 1984. (2) D. F. Farr et al. Fungi on Plants and Plant Products in the United States. The American Phytopathological Society. St. Paul. MN, 1989. (3) S. F. Shamoun et al. Can. J. Plant Pathol. 22:192, 2000.