Improved transient silencing of gene expression in the mosquito female Aedes aegypti.

Gene silencing using RNA interference (RNAi) has become a widely used genetic technique to study gene function in many organisms. In insects, this technique is often applied through the delivery of dsRNA. In the adult female Aedes aegypti, a main vector of human-infecting arboviruses, efficiency of gene silencing following dsRNA injection varies greatly according to targeted genes. Difficult knockdowns using dsRNA can thus hamper gene function analysis. Here, by analysing silencing of three different genes in female Ae. aegypti (p400, ago2 and E75), we show that gene silencing can indeed be dsRNA sequence dependent but different efficiencies do not correlate with dsRNA length. Our findings suggest that silencing is likely also gene dependent, probably due to gene-specific tissue expression and/or feedback mechanisms. We demonstrate that use of high doses of dsRNA can improve knockdown efficiency, and injection of a transfection reagent along with dsRNA reduces the variability in efficiency between replicates. Finally, we show that gene silencing cannot be achieved using siRNA injection in Ae. aegypti adult females. Overall, this work should help future gene function analyses using RNAi in adult females Ae. aegypti, leading toward a better understanding of physiological and infectious processes.

Urinary volatile organic compounds and faecal microbiome profiles in colorectal cancer.

AIM: Volatile organic compounds (VOCs) are potential biomarkers for diagnosing colorectal cancer (CRC). We characterized urinary VOCs from CRC patients, their spouses/cohabitors (spouses) and first-degree relatives (relatives) to determine any differences. Correlation with stool-derived microbiomes was also undertaken. METHODS: Urine from 56 CRC patients, 45 spouses and 37 relatives was assayed using liquid chromatography, field asymmetric ion mobility spectrometry (FAIMS), mass spectrometer technology. Analysis was performed using five-fold cross-validation and a random forest classifier. Faecal microbiome 16S rRNA was sequenced using Illumina MiSeq protocols and analysed using UPARSE and QIIME pipelines. VOC and microbiome profiles were also compared before and after cancer treatment. RESULTS: Urinary VOC profiles of CRC patients were indistinguishable from either spouses or relatives. When spouses and relatives were grouped together to form a larger non-cancer control group (n = 82), their VOC profiles became distinguishable from those of CRC patients (n = 56) with 69% sensitivity and specificity, area under the curve 0.72 (P < 0.001). Microbiome analysis identified > 1300 operational taxonomic units across all groups. The analysis of similarity R value was 0.067 (P < 0.001), with significantly different bacterial abundances in 82 operational taxonomic units (6.2%) by Kruskal-Wallis testing. CRC patients' VOC or stool microbiome profiles were unchanged after treatment. CONCLUSION: Although CRC patients' urinary VOC profiles cannot be differentiated from those of spouses or relatives they can be differentiated from a larger non-cancer control group. Comparison of the groups' microbiomes confirmed differences in bacterial species abundance. The current FAIMS-based assay can detect a unique, but modest, signal in CRC patients' urinary VOCs, which remains unaltered after treatment.

Nutrition in decompensated liver disease: A regional trainee-led audit investigating patient nutrition and outcomes following admission with decompensated chronic liver disease.

OBJECTIVE: To conduct a regional audit assessing the prevalence and management of malnutrition in decompensated liver disease. METHOD: All adults admitted with decompensated cirrhosis over one-month period to participating trusts were included. Malnutrition was identified using MUST and Royal Free Hospital-Nutritional Prioritisation Tool (RFH-NPT). RESULTS: 47 patients were identified. The prevalence of malnutrition was 76.6%. This was independent of age (<65 versus ≥65; p = 1) or aetiology of liver disease (alcohol-related versus not; p = 0.55). Screening was significantly higher on Gastroenterology wards than other wards (77% versus 23%; p = 0.012). RFH-NPT identified 76.6% of patients as malnourished whereas MUST identified 55.3%. Supplementation was prescribed to 83% of eligible patients. 80% was oral supplementation and 20% received NG feeding. Median length of stay (9 (2-62) days) was higher in those prescribed supplements (11 vs 7 days, p = 0.041). Readmission rates were similar regardless of supplementation. Mortality was higher in malnourished patients (p = 0.03) and in those prescribed nutritional supplements at 1, 3 and 6 months (p = 0.026, p = 0.026 and p = 0.008) respectively, who were more likely to have severe liver disease. CONCLUSION: Prevalence of malnutrition is high in patients with decompensated cirrhosis but independent of age and aetiology and associated with higher Child-Pugh scores. The RFH-NPT was a more sensitive screening tool than MUST. Increased nutritional screening was noted on gastroenterology wards with more intervention in those with severe liver disease. Despite the study's limitations, once malnourished, nutritional intervention did not appear to impact on patient readmission or mortality rates therefore, we propose addressing malnutrition by utilising specialty dietician involvement at an earlier stage.

Female Cape sugarbirds (Promerops cafer) modify egg investment both for extra-pair mates and for male tail length.

The differential allocation hypothesis predicts that females should invest more in reproduction when paired with attractive males. We measured egg volume in Cape sugarbirds (Promerops cafer), a sexually dimorphic passerine, in relation to paternity of the offspring and in response to an experimental tail length treatment. We manipulated tail length, after pair formation, but before egg laying: males had their tails either shortened or left unmanipulated. Our manipulation was designed to affect female allocation in a particular breeding attempt rather than long-term mate choice: males with shortened tails would appear to be signalling at a lower level than they should given their quality. We found that egg volume was smaller in the nests of males with experimentally shortened tails but larger when the offspring were the result of extra-pair matings. Both these findings are consistent with the differential allocation hypothesis. We suggest that tail length may be used by females as a cue for mate quality, eliciting reduced female investment when breeding with social mates; and with males with shortened tails.

Finding sex partners on the internet: what is the risk for sexually transmitted infections?

OBJECTIVE: To assess the association between sexual encounters with internet partners and current Chlamydia trachomatis (Ct) and Neisseria gonorrhoeae (GC) infections. METHODS: Between August 2006 and March 2008, patients at the Denver Metro Health Clinic were routinely asked about sexual encounters with internet partners. This retrospective case-control study was limited to patients who tested for Ct/GC at their visit. Analyses were stratified by sexual orientation to account for differences in baseline risk behaviours. RESULTS: Of 14 955 patients with a valid Ct/GC test result, 2802 (19%) were infected with Ct/GC. Stratified by sexual orientation, the prevalence of Ct/GC infection was 17% for men who have sex with men (MSM), 21% for men who have sex with women (MSW) and 16% for women. A total of 339 (23%) MSM, 192 (3%) MSW and 98 (2%) women reported having a sexual encounter with a person they met on the internet in the past 4 months. The estimates of the association between recent internet sex partner and current Ct/GC infection were not significant for MSM (risk ratio (RR): 1.12, 95% confidence interval (CI): 0.84 to 1.49) and women (RR: 0.81, 95% CI 0.45 to 1.48). However, the association appeared to be significantly protective among MSW (RR: 0.66, 95% CI 0.44 to 0.98). CONCLUSIONS: Sexual encounters with internet partners did not appear to be associated with increased risk of current Ct/GC infection among people seeking care at a sexual health clinic. Seeking sexual partners on the internet is a complex behaviour and its implications for STI/HIV infection are not fully understood.

Improving patient outcomes with inguinal hernioplasty-local anaesthesia versus local anaesthesia and conscious sedation: a randomized controlled trial.

PURPOSE: Conscious sedation is regularly used in ambulatory surgery to improve patient outcomes, in particular patient satisfaction. We hypothesized that the addition of conscious sedation would provide greater patient satisfaction with inguinal hernioplasty compared to local anesthesia alone. METHODS: This trial was a single-centre, randomized, placebo-controlled, double-blinded trial where patients undergoing inguinal hernioplasty using local anaesthesia were randomized to receive local anaesthesia alone versus local anaesthesia and conscious sedation. The primary outcome of patient satisfaction was assessed using the Iowa Satisfaction with Anesthesia Scale (ISAS). The study was powered to detect a significant difference in ISAS scores between groups. Comparisons were made using T test and Chi square tests. A p value of less than 0.05 was considered significant. RESULTS: There were 149 patients randomized: 78 to the local anesthesia (LA) group and 71 to the local anaesthesia and conscious sedation (LACS) group. For the primary outcome measure of patient satisfaction, the mean ISAS score was significantly greater in the LACS group (p = 0.009). The experience of pain and pain severity was greater in the LA group (p = 0.016; p = 0.0162 respectively). No statistically significant difference was found between groups with respect to operative time, time to discharge or postoperative complications. CONCLUSION: The use of conscious sedation with local anesthesia for inguinal hernioplasty is safe, results in less pain experience and severity and is associated with better patient satisfaction. The use of conscious sedation does not delay patient discharge.

Gay men who engage in substance use and sexual risk behaviour: a dual-risk group with unique characteristics.

'Recreational' substances used among men having sex with men, and their association with risky unprotected anal intercourse (RUAI) were examined--for the first time in Israel--in an internet-based questionnaire assessing knowledge, practices and motivation. Between March and May 2005, 2873 participants completed the entire questionnaire. Of the total, 669 (23%) reported RUAI during the last six months, and 1319 (46%) used substances during sex. Use of substance was significantly higher among those performing RUAI than those who did not (31.5% versus 26.4%, P=0.03). Involvement in both substance use and RUAI was reported by 366 participants (13%). HIV rates were higher in this dual-risk group (P<0.01), and individuals reported more partners in the last six months than those not part of this dual risk (11.6 versus 8.2, P=0.02). In multivariate analyses, Tel-Aviv residency, lower education, performing receptive RUAI, misperception of HIV transmission and limited negotiation skills were positively associated with this dual-risk behaviour.

The role of surgeon specialization in improving patient outcomes: a challenge for the Caribbean.

Progressive surgeon specialization has been shown to result in improved patient outcomes for many surgical procedures. This has been demonstrated in improved survival following cancer surgery and improved operative morbidity and mortality for other procedures. Concentrating complex surgical cases in centres where case volume and expertise exist should result in better overall surgical care delivery.

Comparing assessment tools for detecting undernutrition in patients with liver cirrhosis.

BACKGROUND AND AIMS: Undernutrition in cirrhotic patients is often poorly recognised until late-stages. The current UK screening tool, the Malnutrition Universal Screening Tool, can miss undernutrition in patients with ascites/fluid retention. A 6-question Liver Disease Undernutrition Screening Tool (LDUST) has been developed in America. METHODS: We sought to compare LDUST with MUST in the detection of undernutrition in 50 inpatients and 50 outpatients with liver cirrhosis in a secondary care setting. This was then validated by a dietitian assessment. RESULTS: Similar patient demographics and liver disease aetiologies were found in the two cohorts. Mean Child-Pugh scores were higher for inpatients, 8.3 (SD 1.9) vs 5.9 (SD 1.2). LDUST detected undernutrition in 45/50 inpatients (90%) and 34/50 outpatients (68%). MUST scores ≥2 were present in 19/50 (38%) inpatients and 9/50 (18%) outpatients. In those with a MUST score <2, LDUST detected undernutrition in 26/31 (84%) inpatients and 27/41 (66%) outpatients. 26 inpatients had undernutrition using LDUST but had a MUST score <2, 20 (76%) of these were deemed to be undernourished by dietetics assessment. LDUST was mostly completed independently or with minimal assistance (80% inpatients, 100% outpatients), with mean completion times of 4 and 3 min for in- and outpatients respectively. CONCLUSION: LDUST is a quick and easy screening tool, which appears better able than MUST to detect undernutrition in cirrhotic patients, including undernutrition missed by MUST. Importantly the tool was validated against dietitian assessments. The high rates of undernutrition among cirrhotic inpatients suggest that screening this cohort is unnecessary, and instead all should undergo dietitian review, with LDUST utilised in an outpatient setting.

Erratum to: The management of intra-abdominal infections from a global perspective: 2017 WSES guidelines for management of intra-abdominal infections.

[This corrects the article DOI: 10.1186/s13017-017-0141-6.].

Breathomics--exhaled volatile organic compound analysis to detect hepatic encephalopathy: a pilot study.

The current diagnostic challenge with diagnosing hepatic encephalopathy (HE) is identifying those with minimal HE as opposed to the more clinically apparent covert/overt HE. Rifaximin, is an effective therapy but earlier identification and treatment of HE could prevent liver disease progression and hospitalization. Our pilot study aimed to analyse breath samples of patients with different HE grades, and controls, using a portable electronic (e) nose. 42 patients were enrolled; 22 with HE and 20 controls. Bedside breath samples were captured and analysed using an uvFAIMS machine (portable e-nose). West Haven criteria applied and MELD scores calculated. We classify HE patients from controls with a sensitivity and specificity of 0.88 (0.73-0.95) and 0.68 (0.51-0.81) respectively, AUROC 0.84 (0.75-0.93). Minimal HE was distinguishable from covert/overt HE with sensitivity of 0.79 and specificity of 0.5, AUROC 0.71 (0.57-0.84). This pilot study has highlighted the potential of breathomics to identify VOCs signatures in HE patients for diagnostic purposes. Importantly this was performed utilizing a non-invasive, portable bedside device and holds potential for future early HE diagnosis.

Necropsy evidence of detection bias in the diagnosis of lung cancer.

The correct diagnosis had not been made during life in 26% of 153 patients with lung cancer found in necropsies performed between 1971 and 1982. The likelihood of a correct antemortem diagnosis showed distinctive gradients in relation to the patients' history and amount of cigarette smoking, symptomatic manifestations, and anatomic extensiveness of the cancers. However, cigarette smoking still exerted a diagnostic effect in patients with similar symptoms and similar degrees of anatomic spread. Furthermore, if a lesion was present, chest films were more likely to be radiologically interpreted as a cancer in smokers. The results suggest that smokers receive preferential consideration regarding the diagnosis of lung cancer. This detection bias can have adverse scientific consequences in depriving nonsmokers of suitable therapy, in leading to falsely high estimates of the true magnitude of the smoking/lung cancer association, and in distracting etiologic attention from other agents that may cause lung cancer.

The role of susceptibility bias in epidemiologic research.

Because prognostic adjustment in epidemiologic studies of disease etiology has usually been limited to matchings or stratifications based on demographic characteristics, clinical sources of susceptibility bias have received little attention. This may have led to an incorrect association in two prominent epidemiologic relationships: that between clear-cell vaginal carcinoma and the use of diethylstilbestrol to treat women with bleeding or previous pregnancy loss; and that in the conflicting results of the studies linking sex steroids to the risk of birth defects. The recognition and management of susceptibility bias requires attention to the patients' clinical status at the time of exposure to the alleged causative agent, and also requires collecting and analyzing clinical data excluded or ignored in most epidemiologic studies. To avoid susceptibility bias, data about bleeding, threatened abortion, and other clinical reasons for prescribing therapy are needed for the appropriate matchings or stratifications.

Clinicopathologic profile of gastric carcinomas at the University Hospital of the West Indies.

The objective of this study was to examine the clinicopathologic features of gastric cancer seen at the University Hospital of the West Indies (UHWI) and to compare the findings with other studies. A retrospective study was conducted using data obtained from the surgical pathology reports of all gastrectomies and gastric biopsies during the period January 1993 and December 2002. Additional cases were identified from the Department of Surgery's audit database. Demographic, clinical and pathological features were analyzed. Two hundred and sixteen patients were identified, 126 males and 90 females. One hundred and thirty-six underwent biopsy procedures but no definitive surgery aimed at cancer eradication, while 70 had gastrectomy. The peak age prevalence in both males and females was the 70-79-year age group. While the antrum was the commonest site, there was an overall increase in tumours of the gastro-oesophageal junction and tumours of the entire stomach in the latter five-year period of the review especially in the 50-59-year age group. Epigastric pain and constitutional symptoms were the common presenting features, and the most common gross tumour characteristic was an ulcerating mass, while histologically, the intestinal variety was most common. Lymph node metastases were common. Helicobacter pylori (Hpylori) were present in 16.7% while chronic multifocal atrophic gastritis was present in 40%. This study indicates that the gastric cancer pattern is typical of developing countries. However, the low prevalence of H pylori in the resected specimens may indicate the importance of other risk factors for gastric cancer development in this population. This warrants further study.

Analysis of pulsatile secretion of thyrotropin and growth hormone in the hypothyroid rat.

To characterize the role of TRH in the generation of TSH pulsatility as well as the effect of hypothyroidism on episodic GH secretion, blood was constantly withdrawn (30-60 microliters/min) from rats treated with 0.02% methimazole in the drinking water for 8-10 days. This treatment significantly reduced circulating levels of both T3 and T4 and elevated plasma TSH; however, since thyroid hormone titers were still detectable (T3, 39.6 +/- 5.3 vs. 89.8 +/- 5.3 ng/dl in euthyroid animals), methimazole-treated rats were referred to as being mildly hypothyroid. TSH was found to be secreted in secretory bursts, consisting of one to several peaks in these rats. Pulsar analysis of TSH secretory profiles revealed a mean pulse frequency of 2.8 pulses/h, a mean pulse amplitude of 10 ng/pulse, and a mean pulse duration of 0.2 h. Euthyroid rats exhibited similar fluctuations of circulating TSH levels; however, due to the variability of the TSH RIA in the range of euthyroid TSH titers, no significant pulsatility was detected by Pulsar. Mean plasma TSH levels in eu- and hypothyroid rats were 2.3 +/- 0.3 and 14.6 +/- 1.8 ng/ml, respectively. To confirm that the TRH antiserum (TRH-AS) used in the present study for passive immunization had sufficient binding capacity to absorb endogenous TRH release, euthyroid rats were pretreated with either normal rabbit serum or TRH-AS, followed by the injection of clonidine (100 micrograms/kg BW, iv). This alpha 2-adrenergic agonist caused a significant (P < 0.01) 12.7-fold rise in plasma TSH levels in normal rabbit serum-treated animals, which was completely abolished by TRH-AS pretreatment, indicating that clonidine stimulates TSH secretion via activation of hypothalamic TRH release. When TRH-AS was slowly infused into hypothyroid rats that were sampled frequently for the detection of TSH pulsatility, it caused a significant (60.3%; P < 0.01) decrease in mean TSH levels, with TSH titers approaching euthyroid concentrations 1 h after the infusion of TRH-AS. The antiserum treatment also caused the disappearance of statistically significant (Pulsar) TSH secretory pulses. Mild hypothyroidism shifted the GH secretory profiles from a low frequency, high amplitude in euthyroid animals to a high frequency, low amplitude pattern in hypothyroid rats. Mean GH levels in hypothyroid rats were 76% lower than those in euthyroid controls. These findings show that TSH is secreted in a pulsatile fashion in the hypothyroid rat and that TRH is predominantly responsible for the generation of TSH pulsatility.(ABSTRACT TRUNCATED AT 400 WORDS)

Meningiomas are not significantly associated with breast cancer.

We studied 283 meningiomas seen at the University of Kansas, Kansas City, from 1948 through 1984, identifying all additional nonmeningeal malignancies and primary brain tumors in these patients and calculating the expected number of additional tumors by the use of a person-year method from age and sex-matched cancer incidence data. We determined expected numbers of total neoplasms in our meningioma population as well as the expected numbers in each major organ system for the sexes independently and together. We then calculated standard morbidity ratios and 95% confidence intervals for each tumor type. The number of breast cancers did not reach statistical significance. We found a significantly increased number of second primary brain tumors in women (standard morbidity ratio, 8.0; 95% confidence interval, 2.2 to 20.4) and an increased number of thyroid cancers in both sexes (standard morbidity ratio, 7.5; 95% confidence interval, 1.5 to 21.9).

Use of the alveolar-arterial oxygen gradient in the diagnosis of pulmonary embolism.

BACKGROUND: Arterial blood gas (ABG) values and the alveolar-arterial oxygen (A-a) gradient are sensitive indicators of pulmonary pathology. Alone, they are not diagnostic of pulmonary embolism (PE), but they may be useful in excluding the diagnosis of PE if their values fall within the normal range. The purpose of this study was to determine the diagnostic value of a normal A-a gradient in ruling out PE. PATIENTS AND METHODS: The Derivation Set came from the records of all patients at Cleveland MetroHealth Medical Center who received a ventilation/perfusion (V/Q) scan for suspected PE in 1988 or 1989. Demographic and clinical data were obtained that included risk factors, symptoms, signs, and laboratory tests. A-a gradients were calculated using a standard equation; a normal gradient was defined as less than or equal to (age/4 + 4). The A-a gradient was examined before and after controlling for PE risk factors. The Validation Set was comprised of patients who had V/Q scans in 1987 and 1990. RESULTS: Among the 873 patients in the Derivation Set, 540 had simultaneous room air ABG determinations. Of these patients, 109 (20%) had a discharge diagnosis of PE. Only 1 of 57 (1.8%; 95% confidence interval [CI]: 0.9%-10.7%) patients without a history of PE or deep venous thrombosis (DVT) and with a normal A-a gradient had PE. Among the 805 V/Q patients in the Validation Set, 489 had simultaneous room air/ABG determinations. Of these, 75 (15%) had PE. Only 1 of 54 (1.9%; 95% CI: 0.1%-11.2%) patients without a history of PE or DVT and with a normal A-a gradient had PE. CONCLUSIONS: A normal A-a gradient among patients without a history of PE or DVT makes the diagnosis of PE unlikely. Further diagnostic evaluation may be unnecessary in this subgroup of patients.

Diethylstilbestrol and clear cell vaginal carcinoma. Reappraisal of the epidemiologic evidence.

The association between DES and the development of clear cell vaginal carcinoma may have several alternative explanations rather than a cause- and-effect relation. One important possibility is that susceptibility bias, arising from reasons for use of the drug in a problem pregnancy, is a prime source of the observed effect in the case-control studies. Rather than being a cause of clear cell vaginal carcinoma, exposure to DES would serve as a prognostic "marker" to identify women born of problem pregnancies that increased their risk for development of the disease. Since medical advances in prenatal and perinatal care allowed these problem pregnancies to be carried to the term delivery of a viable child, DES may have been associated with an increased occurrence of clear cell vaginal carcinoma--without causing the disease. Another alternative hypothesis is needed to account for the high rates of reported previous exposure to DES in the case subjects of the two case-control studies. These rates may have been elevated by some form of interviewer bias or recall bias. The relatively high incidence of clear cell vaginal carcinoma that would be expected from the results of these case-control studies has not been observed in cohort studies. No instances of clear cell vaginal carcinoma have thus far been found in suitably assembled cohorts of women exposed to DES in utero. The history of science contains abundant examples of fervently held beliefs about cause- and-effect relations that were later found to be erroneous. The existing evidence of a DES/vaginal cancer relation is currently too weak for the causal role of DES to be regarded as established. To get better evidence, the problems of biased comparison and biased data can be addressed in at least three ways. The first is to carry out an appropriately objective new case-control study, with suitably chosen control subjects; the second is to study the issue of susceptibility bias by getting additional information about the occurrence of problem pregnancies in the mothers of patients with clear cell vaginal carcinoma who were not exposed to DES; the third is to review past tissue specimens from previously diagnosed genital adenocarcinomas, searching for clear cell cancers that may have been unrecognized. Until the suspected biases are addressed and either confirmed or refuted, the relation between DES and clear cell vaginal carcinoma remains a statistical association that is unaccompanied by the quality of evidence required for scientific conclusions.

Clinical features of lung cancers discovered as a postmortem "surprise".

Despite improved modern diagnostic techniques, many patients with primary lung cancer escape detection of their disease during life. In a review of postmortem records at a university hospital, 28 percent of 153 primary lung cancers found at necropsy had not been diagnosed while the patient was alive. The male/female ratio was 1.3 in this undetected group, compared with 2.3 in the detected group. The main clinical features that seemed to lead to nondiagnosis were a terminal clinical state in patients who were too sick for further diagnostic searches, the absence of suggestive primary symptoms, a chest x-ray film interpreted as not showing primary lung cancer, and the absence of cigarette smoking. Among the patients with lung cancer at necropsy, the proportion of nonsmokers was higher in the previously undiagnosed group than in the group with antemortem diagnoses, even when patients were stratified for primary symptoms. The findings suggest the need for diagnostic alertness to the possibility that curable lung cancer can occur in patients who have a positive chest-film lesion but who are nonsmokers and who lack typical symptoms.