Impact of COVID-19 on CT-diagnosed acute appendicitis and diverticulitis: was there collateral damage?

AIM: To evaluate the change in diagnosis rates, disease severity at presentation, and treatment of acute appendicitis and diverticulitis during the COVID-19 shutdown. MATERIALS AND METHODS: Following institutional review board approval, 6,002 CT examinations performed at five hospitals for suspected acute appendicitis and/or diverticulitis over the 12 weeks preceding and following the shutdown were reviewed retrospectively. Semi-automated language analysis (SALA) of the report classified 3,676 CT examinations as negative. Images of the remaining 2,326 CT examinations were reviewed manually and classified as positive or negative. Positive cases were graded as non-perforated; perforated, contained; and perforated, free. RESULTS: CT examinations performed for suspected appendicitis and/or diverticulitis decreased from 3,558 to 2,200 following the shutdown. The rates of positive diagnoses before and after shutdown were 4% (144) and 4% (100) for appendicitis and 8% (284) and 7% (159) for diverticulitis (p>0.2 for both). For positive CT examinations, the rates of perforation, hospitalisation, surgery, and catheter drainage changed by -2%, -3%, -2%, and -3% for appendicitis (n=244, p>0.3 for all) and +6% (p=0.2) +9% (p=0.06), +4% (p=0.01) and +1% (p=0.6) for diverticulitis (n=443). CONCLUSION: CT examinations performed for suspected appendicitis or diverticulitis declined after the shutdown, likely reflecting patients leaving urban centres and altered triage of non-COVID-19 patients. The diagnosis rates, disease severity at presentation, and treatment approach otherwise remained mostly unchanged.

The inner membrane protein YhiM is necessary for Escherichia coli growth at high temperatures and low osmolarity.

To survive, Escherichia coli must be able to survive in rapidly changing environmental conditions including changes in temperature and osmolarity. We have studied the role of the inner membrane protein YhiM in changing environmental conditions. Our data indicate that YhiM is required for normal growth at 37 and 41 °C but not 21 °C. YhiM-deficient cells grown at high temperatures spend more time in lag phase and stop growing at lower cell densities in comparison with their wild-type counterparts. They also have growth defects in low NaCl medium at 37 °C and do not grow at all at 41 °C. The effects of low NaCl can be rescued by addition of KCl or sucrose to the low salt medium. Finally, YhiM-deficient cells fail to grow in dilute medium at 41 °C. These data suggest that YhiM may be important in protecting the cells from changes in temperature and osmolarity.

Integration of geriatric mental health screening into a primary care practice: a patient satisfaction survey.

OBJECTIVE: Colocation of mental health screening, assessment, and treatment in primary care reduces stigma, improves access, and increases coordination of care between mental health and primary care providers. However, little information exists regarding older adults' attitudes about screening for mental health problems in primary care. The objective of this study was to evaluate older primary care patients' acceptance of and satisfaction with screening for depression and anxiety. METHODS: The study was conducted at an urban, academically affiliated primary care practice serving older adults. Study patients (N = 107) were screened for depression/anxiety and underwent a post-screening survey/interview to assess their reactions to the screening experience. RESULTS: Most patients (88.6%) found the length of the screening to be "just right." A majority found the screening questions somewhat or very acceptable (73.4%) and not at all difficult (81.9%). Most participants did not find the questions stressful (84.9%) or intrusive (91.5%); and a majority were not at all embarrassed (93.4%), upset (93.4%), or uncomfortable (88.8%) during the screening process. When asked about frequency of screening, most patients (72.4%) desired screening for depression/anxiety yearly or more. Of the 79 patients who had spoken with their physicians about mental health during the visit, 89.8% reported that it was easy or very easy to talk with their physicians about depression/anxiety. Multivariate results showed that patients with higher anxiety had a lower positive reaction to the screen when controlling for gender, age, and patient-physician communication. CONCLUSIONS: These results demonstrate strong patient support for depression and anxiety screening in primary care.

When do we transfuse cryoprecipitate?

BACKGROUND: The 2001 National Health and Medical Research Council/Australasian Society of Blood Transfusion Clinical Practice Guidelines for cryoprecipitate are being updated, and cryoprecipitate has been incorporated into new Patient Blood Management modules. AIMS: This clinical audit sought to clarify current cryoprecipitate use in Victoria, Tasmania and the Australian Capital Territory; assess adherence to guidelines; and gain insights into deviations from recommended practice. This information can be utilised in updating guidelines to make them more relevant, to identify areas for clinician education and to form a baseline of practice prior to release of the 2011 guidelines. METHODS: Participating institutions were invited to audit up to 30 consecutive episodes of cryoprecipitate transfusion over an 11-month period in 2008. The audits were conducted using a standardised pro forma and involved review of patient records. These were collated electronically using algorithms to determine alignment versus non-alignment with guidelines. RESULTS: Cryoprecipitate is used in a variety of situations with surgery accounting for the highest volume. Twenty-six per cent (26%) of transfusions were aligned with 2001 guidelines rising to 61% with a modified fibrinogen trigger. Fibrinogen levels did not appear to dictate all clinical decisions regarding cryoprecipitate use perhaps owing to the acuity of many cases. Additional bleeding risk together with low fibrinogen levels (e.g. thrombocytopenic patients) may contribute to empiric cryoprecipitate use. CONCLUSIONS: These results highlight discrepancies between guidelines and practice, providing rationale for the update of the guidelines that is currently underway. Cryoprecipitate has attendant risks, and it is appropriate that transfusion be restricted to situations with good evidence or sound principles to underpin use.

Coexpression of potato type I and II proteinase inhibitors gives cotton plants protection against insect damage in the field.

Potato type I and II serine protease inhibitors are produced by solanaceous plants as a defense mechanism against insects and microbes. Nicotiana alata proteinase inhibitor (NaPI) is a multidomain potato type II inhibitor (pin II) that is produced at high levels in the female reproductive tissues of the ornamental tobacco, Nicotiana alata. The individual inhibitory domains of NaPI target the major classes of digestive enzymes, trypsin and chymotrypsin, in the gut of lepidopteran larval pests. Although consumption of NaPI dramatically reduced the growth and development of a major insect pest, Helicoverpa punctigera, we discovered that surviving larvae had high levels of chymotrypsin activity resistant to inhibition by NaPI. We found a potato type I inhibitor, Solanum tuberosum potato type I inhibitor (StPin1A), was a strong inhibitor of the NaPI-resistant chymotrypsin activity. The combined inhibitory effect of NaPI and StPin1A on H. armigera larval growth in the laboratory was reflected in the increased yield of cotton bolls in field trials of transgenic plants expressing both inhibitors. Better crop protection thus is achieved using combinations of inhibitors in which one class of proteinase inhibitor is used to match the genetic capacity of an insect to adapt to a second class of proteinase inhibitor.

Molecular basis for the resistance of an insect chymotrypsin to a potato type II proteinase inhibitor.

Plants produce a variety of proteinase inhibitors (PIs) that have a major function in defense against insect herbivores. In turn, insects have developed strategies to minimize the effect of dietary PIs on digestion. We have discovered that Helicoverpa larvae that survive consumption of a multidomain serine PI from Nicotiana alata (NaPI) contain high levels of a chymotrypsin that is not inhibited by NaPI. Here we describe the isolation of this NaPI-resistant chymotrypsin and an NaPI-susceptible chymotrypsin from Helicoverpa larvae, together with their corresponding cDNAs. We investigated the mechanism of resistance by mutating selected positions of the NaPI-susceptible chymotrypsin using the corresponding amino acids of the NaPI-resistant chymotrypsin. Four critical residues that conferred resistance to NaPI were identified. Molecular modeling revealed that a Phe-->Leu substitution at position 37 in the chymotrypsin results in the loss of important binding contacts with NaPI. Identification of the molecular mechanisms that contribute to PI resistance in insect digestive proteases will enable us to develop better inhibitors for the control of lepidopteran species that are major agricultural pests worldwide.

Sindbis virus induces the production of a novel class of endogenous siRNAs in Aedes aegypti mosquitoes.

Small RNA regulatory pathways are used to control the activity of transposons, regulate gene expression and resist infecting viruses. We examined the biogenesis of mRNA-derived endogenous short-interfering RNAs (endo-siRNAs) in the disease vector mosquito Aedes aegypti. Under standard conditions, mRNA-derived endo-siRNAs were produced from the bidirectional transcription of tail-tail overlapping gene pairs. Upon infection with the alphavirus, Sindbis virus (SINV), another class of mRNA-derived endo-siRNAs was observed. Genes producing SINV-induced endo-siRNAs were not enriched for overlapping partners or nearby genes, but were enriched for transcripts with long 3' untranslated regions. Endo-siRNAs from this class derived uniformly from the entire length of the target transcript, and were found to regulate the transcript levels of the genes from which they were derived. Strand-specific quantitative PCR experiments demonstrated that antisense strands of targeted mRNA genes were produced to exonic, but not intronic regions. Finally, small RNAs mapped to both sense and antisense strands of exon-exon junctions, suggesting double-stranded RNA precursors to SINV-induced endo-siRNAs may be synthesized from mature mRNA templates. These results suggest additional complexity in small RNA pathways and gene regulation in the presence of an infecting virus in disease vector mosquitoes.

Prophylactic 5-Fr pancreatic duct stents are superior to 3-Fr stents: a randomized controlled trial.

BACKGROUND: Temporary prophylactic pancreatic duct stenting effectively reduces post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP) in high-risk patients, but the optimal stent remains unclear. We compared rate of spontaneous passage, and technical difficulty of placement for 3-Fr and 5-Fr stents. METHODS: A randomized controlled trial at a single academic medical center. Patients deemed high risk for PEP randomly received 5-Fr or 3-Fr pancreatic duct stents. Primary outcome was spontaneous stent passage by 2 weeks. Secondary outcomes were ease and time for stent placement, and number of guide wires required for the entire procedure. RESULTS: Patients (69 female [89 %]; mean age 44.9 years, standard deviation [SD] 16.8) were randomly assigned to receive 5-Fr (n = 38) and 3-Fr (n = 40) stents. Indications for stenting were similar. Seven patients in the 3-Fr group actually received a 5-Fr stent, and two in the 5-Fr group had a 3-Fr stent. Spontaneous passage or non-passage was confirmed in 64 (83 %). No statistically significant difference in spontaneous passage rates was seen (5-Fr group, 68.4 %; 3-Fr group 75.0 %; P = 0.617). Non-passage rates were 10.5 % (5-Fr group) and 10.0 % (3-Fr group) ( P = 1.00). The study was stopped after a futility analysis for the primary end point. Placement of 5-Fr stents was rated easier, at a mean score of 1.8 (5-Fr) vs. 3.4 (3-Fr), P < 0.001, with a trend towards being faster, 9.2 vs. 11.1 minutes ( P = 0.355). Fewer guide wires were required for 5-Fr stent placement, 1.5 vs. 1.9 ( P = 0.002). PEP rates did not differ ( P = 0.519). CONCLUSION: Placement of 5-Fr compared to 3-Fr pancreatic duct stents for PEP prophylaxis is easier, faster, and requires fewer wires. No statistically significant difference in spontaneous passage was found between the two sizes.

Validation of novel promoter sequences derived from two endogenous ubiquitin genes in transgenic Aedes aegypti.

To date, only a limited number of promoter sequences have been described to drive transgene expression in the disease vector Aedes aegypti. We sought to increase this repertoire by characterizing the ability of upstream sequences derived from the Ae. aegypti Ub(L40) and polyubiquitin genes to drive the expression of marker proteins. Both genomic fragments were able to drive robust expression of luciferase in cultured mosquito cells. Following Mos1-transformation, the Ub(L40) promoter drove strong expression of a fluorescent marker in early larvae and in ovaries, while the polyubiquitin promoter drove robust EGFP expression in all stages of development, including constitutive expression throughout the midgut. These promoter fragments provide two new expression profiles for future Ae. aegypti genetic experiments.

Homing endonucleases catalyze double-stranded DNA breaks and somatic transgene excision in Aedes aegypti.

Aedes aegypti is a major vector of arthropod-borne viruses such as yellow fever virus and dengue viruses. Efforts to discern the function of genes involved in important behaviours, such as vector competence and host seeking through reverse genetics, would greatly benefit from the ability to generate targeted gene disruptions. Homing endonucleases are selfish elements which catalyze double-stranded DNA (dsDNA) breaks in a sequence-specific manner. In this report we demonstrate that the homing endonucleases I-PpoI, I-SceI, I-CreI and I-AniI are all able to induce dsDNA breaks in adult female Ae. aegypti chromosomes as well as catalyze the somatic excision of a transgene. These experiments provide evidence that homing endonucleases can be used to manipulate the genome of this important disease vector.

Self-incompatibility: a self-recognition system in plants.

Self-incompatibility (SI), a genetically controlled mechanism to prevent inbreeding in plants, offers a relatively simple model system for studying the interactions between plant cells or between a plant cell and the secreted product or products of another cell. Examples of two major types of SI, gametophytic and sporophytic, have been studied by cloning cDNAs corresponding to glycoproteins of the female tissues that segregate with particular variants encoded by the putative S locus. These secreted glycoproteins are envisaged to interact with the currently undescribed pollen component to cause arrest of pollen tube growth.

DNA markers for nervous system diseases.

Recombinant DNA technology has provided a vast new source of DNA markers displaying heritable sequence variation in humans. These markers can be used in family studies to identify the chromosomal location of defective genes causing nervous system disorders. The discovery of a DNA marker linked to Huntington's disease has opened new avenues of research into this disorder and may ultimately permit cloning and characterization of the defective gene.

Risk of malignancy in resected cystic tumors of the pancreas < or =3 cm in size: is it safe to observe asymptomatic patients? A multi-institutional report.

Recent international consensus guidelines propose that cystic pancreatic tumors less than 3 cm in size in asymptomatic patients with no radiographic features concerning for malignancy are safe to observe; however, there is little published data to support this recommendation. The purpose of this study was to determine the prevalence of malignancy in this group of patients using pancreatic resection databases from five high-volume pancreatic centers to assess the appropriateness of these guidelines. All pancreatic resections performed for cystic neoplasms < or =3 cm in size were evaluated over the time period of 1998-2006. One hundred sixty-six cases were identified, and the clinical, radiographic, and pathological data were reviewed. The correlation with age, gender, and symptoms (abdominal pain, nausea and vomiting, jaundice, presence of pancreatitis, unexplained weight loss, and anorexia), radiographic features suggestive of malignancy by either computed tomography, magnetic resonance imaging, or endoscopic ultrasound (presence of solid component, lymphadenopathy, or dilated main pancreatic duct or common bile duct), and the presence of malignancy was assessed using univariate and multivariate analysis. Among the 166 pancreatic resections for cystic pancreatic tumors < or =3 cm, 135 cases were benign [38 serous cystadenomas, 35 mucinous cystic neoplasms, 60 intraductal papillary mucinous neoplasms (IPMN), 1 cystic papillary tumor, and 1 cystic islet cell tumor], whereas 31 cases were malignant (14 mucinous cystic adenocarcinomas and 13 invasive carcinomas and 4 in situ carcinomas arising in the setting of IPMN). A greater incidence of cystic neoplasms was seen in female patients (99/166, 60%). Gender was a predictor of malignant pathology, with male patients having a higher incidence of malignancy (19/67, 28%) compared to female patients (12/99, 12%; p < 0.02). Older age was associated with malignancy (mean age 67 years in patients with malignant disease vs 62 years in patients with benign lesions (p < 0.05). A majority of the patients with malignancy were symptomatic (28/31, 90%). Symptoms that correlated with malignancy included jaundice (p < 0.001), weight loss (p < 0.003), and anorexia (p < 0.05). Radiographic features that correlated with malignancy were presence of a solid component (p < 0.0001), main pancreatic duct dilation (p = 0.002), common bile duct dilation (p < 0.001), and lymphadenopathy (p < 0.002). Twenty-seven of 31(87%) patients with malignant lesions had at least one radiographic feature concerning for malignancy. Forty-five patients (27%) were identified as having asymptomatic cystic neoplasms. All but three (6.6%) of the patients in this group had benign disease. Of the patients that had no symptoms and no radiographic features, 1 out of 30 (3.3%) had malignancy (carcinoma in situ arising in a side branch IPMN). Malignancy in cystic neoplasms < or =3 cm in size was associated with older age, male gender, presence of symptoms (jaundice, weight loss, and anorexia), and presence of concerning radiographic features (solid component, main pancreatic duct dilation, common bile duct dilation, and lymphadenopathy). Among asymptomatic patients that displayed no discernable radiographic features suggestive of malignancy who underwent resection, the incidence of occult malignancy was 3.3%. This study suggests that a group of patients with small cystic pancreatic neoplasms who have low risk of malignancy can be identified, and selective resection of these lesions may be appropriate.

Development of a solar-powered microbial fuel cell.

AIMS: To understand factors that impact solar-powered electricity generation by Rhodobacter sphaeroides in a single-chamber microbial fuel cell (MFC). METHODS AND RESULTS: The MFC used submerged platinum-coated carbon paper anodes and cathodes of the same material, in contact with atmospheric oxygen. Power was measured by monitoring voltage drop across an external resistance. Biohydrogen production and in situ hydrogen oxidation were identified as the main mechanisms for electron transfer to the MFC circuit. The nitrogen source affected MFC performance, with glutamate and nitrate-enhancing power production over ammonium. CONCLUSIONS: Power generation depended on the nature of the nitrogen source and on the availability of light. With light, the maximum point power density was 790 mW m(-2) (2.9 W m(-3)). In the dark, power output was less than 0.5 mW m(-2) (0.008 W m(-3)). Also, sustainable electrochemical activity was possible in cultures that did not receive a nitrogen source. SIGNIFICANCE AND IMPACT OF THE STUDY: We show conditions at which solar energy can serve as an alternative energy source for MFC operation. Power densities obtained with these one-chamber solar-driven MFC were comparable with densities reported in nonphotosynthetic MFC and sustainable for longer times than with previous work on two-chamber systems using photosynthetic bacteria.

Molecular basis for the production of cyclic peptides by plant asparaginyl endopeptidases.

Asparaginyl endopeptidases (AEPs) are proteases that have crucial roles in plant defense and seed storage protein maturation. Select plant AEPs, however, do not function as proteases but as transpeptidases (ligases) catalyzing the intra-molecular ligation of peptide termini, which leads to peptide cyclization. These ligase-type AEPs have potential biotechnological applications ranging from in vitro peptide engineering to plant molecular farming, but the structural features enabling these enzymes to catalyze peptide ligation/cyclization rather than proteolysis are currently unknown. Here, we compare the sequences, structures, and functions of diverse plant AEPs by combining molecular modeling, sequence space analysis, and functional testing in planta. We find that changes within the substrate-binding pocket and an adjacent loop, here named the "marker of ligase activity", together play a key role for AEP ligase efficiency. Identification of these structural determinants may facilitate the discovery of more ligase-type AEPs and the engineering of AEPs with tailored catalytic properties.

Action of the Style Product of the Self-Incompatibility Gene of Nicotiana alata (S-RNase) on in Vitro-Grown Pollen Tubes.

The products of the S-locus expressed in female tissues of Nicotiana alata are ribonucleases (S-RNases). The arrest of growth of incompatible pollen tubes in styles may result from entry of the S-RNase into the pollen tube and degradation of pollen tube RNA. We investigated the action of isolated S-RNases on pollen tubes grown in vitro and found that S-RNase is taken up by the pollen without substantial alteration. The S-RNases inhibit incorporation of exogenously added radioactive amino acids into protein by the germinated pollen. The S-RNases also inhibit in vitro translation of pollen tube RNA in a wheat germ cell-free extract. We found no evidence for a specific mRNA substrate for the S-RNases, which implies that if RNase activity is involved in the control of self-incompatibility, allelic specificity is more likely to depend on the selective uptake of S-RNases into pollen tubes or their selective activation or inactivation by pollen factors, rather than cleavage of a specific substrate. Heat treating S2-RNase largely destroys its RNase activity but increases its inhibitory effect on in vitro pollen tube growth. This effect is not due to an increased uptake of S2-RNase by the pollen but is associated with a greatly enhanced accumulation of S2-RNase on the outer surface of the pollen grains.

Structure of a putative ancestral protein encoded by a single sequence repeat from a multidomain proteinase inhibitor gene from Nicotiana alata.

BACKGROUND: The ornamental tobacco Nicotiana alata produces a series of proteinase inhibitors (PIs) that are derived from a 43 kDa precursor protein, NaProPI. NaProPI contains six highly homologous repeats that fold to generate six separate structural domains, each corresponding to one of the native PIs. An unusual feature of NaProPI is that the structural domains lie across adjacent repeats and that the sixth PI domain is generated from fragments of the first and sixth repeats. Although the homology of the repeats suggests that they may have arisen from gene duplication, the observed folding does not appear to support this. This study of the solution structure of a single NaProPI repeat (aPI1) forms a basis for unravelling the mechanism by which this protein may have evolved. RESULTS: The three-dimensional structure of aPI1 closely resembles the triple-stranded antiparallel beta sheet observed in each of the native PIs. The five-residue sequence Glu-Glu-Lys-Lys-Asn, which forms the linker between the six structural domains in NaProPI, exists as a disordered loop in aPI1. The presence of this loop in aPI1 results in a loss of the characteristically flat and disc-like topography of the native inhibitors. CONCLUSIONS: A single repeat from NaProPI is capable of folding into a compact globular domain that displays native-like PI activity. Consequently, it is possible that a similar single-domain inhibitor represents the ancestral protein from which NaProPI evolved.

Membrane-less organic-inorganic aqueous flow batteries with improved cell potential.

A membrane-less organic-inorganic flow battery based on zinc and quinone species is proposed. By virtue of the slow dissolution rate of the deposited anode (<11.5 mg h-1 cm-2), the battery has a cell voltage of ca. 1.52 V with an average energy efficiency of ca. 73% at 30 mA cm-2 over 12 cycles.

Defensins--components of the innate immune system in plants.

Plant defensins are small (c.a. 5 kDa), basic, cysteine-rich proteins with antimicrobial activities. They are ubiquitous in plants and form part of the innate immunity arsenal. Plant defensins are encoded by small multigene families and are expressed in various plant tissues, but are best characterized in seeds. They are typically produced as preproteins, however, a small subset are produced as larger precursors with C-terminal prodomains. To date, the three-dimensional solution structures of seven seed- and two floral-derived defensins have been elucidated by (1)H-NMR spectroscopy. Despite limited amino acid sequence identities, these defensins have comparable global folds with features that are characteristic of the cysteine-stabilized alphabeta (CSalphabeta) motif. Interestingly, their structures are remarkably similar to those of insect defensins and scorpion toxins. Functionally, these proteins exhibit a diverse array of biological activities, although they all serve a common function as defenders of their hosts. This review describes the distribution, biosynthesis, structure, function and mode of action of plant defensins and reflects on their potential in agribiotechnological applications.