The impact of Victorian COVID-19 lockdowns on the presentation and management of acute appendicitis.

BACKGROUNDS: The COVID-19 pandemic presents ongoing challenges for healthcare. Stay at Home orders ('lockdowns') and community fears have been suggested to create reluctance to seek healthcare. We aimed to determine whether the rates of perforated appendicitis and negative appendicectomy have been affected by the pandemic, and to analyse the effect of lockdowns on the management of acute appendicitis in Victoria. METHODS: We conducted a retrospective audit of emergency appendicectomies performed under adult General Surgery units at Monash Health in Victoria from January 2019 to September 2021, including 242 days of lockdown. RESULTS: 2459 patients were included. Fewer patients had perforated appendicitis during the second lockdown (6.3% versus 10.7% baseline; p = 0.027). The rate of negative appendicectomy was reduced during the first lockdown (4.1% versus 14.9% baseline; p = 0.002) and during intervals between lockdown in 2021 (9.8%; p = 0.010). There was no difference in the rate of perforated appendicitis or negative appendicectomy at other times. Time to surgery and number of appendicectomies performed were also not significantly different. Fewer appendicectomies were performed after hours during lockdowns and in 2021 more generally compared to baseline (p < 0.05). CONCLUSION: The lower negative appendicectomy rate during the first lockdown may reflect increased pre-operative imaging or clinical observation for undifferentiated presentations. There was a reduction in perforated appendicitis during the second lockdown, and no significant difference at other times. Contrary to other studies, lockdowns associated with the COVID-19 pandemic may not create a reluctance to seek healthcare in all regions.

The Role of Magnetic Resonance Imaging in a Difficult Case of Gallstone Ileus.

Gallstone ileus is an uncommon condition that is difficult to diagnose clinically. Although several cases have been reported in the literature, radiolucent gallstones in the setting of gallstone ileus are an exceedingly rare occurrence, and we have not identified any authors who used magnetic resonance imaging (MRI) for the acute diagnosis of this condition. While an MRI is the gold standard for visualizing gallstones, inpatient MRIs are difficult to obtain, even in resource-rich settings. However, if given a high index of suspicion for gallstone ileus, it is pertinent to advocate for an inpatient MRI despite a resolution of patients' symptoms due to the nature of the disease symptomology.

A rare case of iliopsoas abscess caused by a retained shrapnel from a blast injury.

Iliopsoas abscesses (IPA) are uncommon, with an associated mortality rate of up to 20%. We describe the case of a 55-year-old man war veteran who presented with an unusual cause of IPA secondary to retained foreign body (FB). His initial trauma 30 years before was a result of a blast injury with shrapnel penetration suffered after inadvertently driving over a landmine as an ambulance driver in a conflict region. A CT scan was performed, revealing a 13 mmx8 mm radio-opaque FB within the right psoas at the level of the fifth lumbar vertebra with a surrounding collection. Subsequent open surgical exploration removed two gravel fragments. Given the knowledge of a traumatic blast injury with retained FB and repeated episodes of sepsis, surgical exploration is warranted. To our knowledge, this is the first case of recurrent IPA secondary to a retained FB from a historical trauma.

Mineral protection regulates long-term global preservation of natural organic carbon.

The balance between photosynthetic organic carbon production and respiration controls atmospheric composition and climate1,2. The majority of organic carbon is respired back to carbon dioxide in the biosphere, but a small fraction escapes remineralization and is preserved over geological timescales3. By removing reduced carbon from Earth's surface, this sequestration process promotes atmospheric oxygen accumulation2 and carbon dioxide removal1. Two major mechanisms have been proposed to explain organic carbon preservation: selective preservation of biochemically unreactive compounds4,5 and protection resulting from interactions with a mineral matrix6,7. Although both mechanisms can operate across a range of environments and timescales, their global relative importance on 1,000-year to 100,000-year timescales remains uncertain4. Here we present a global dataset of the distributions of organic carbon activation energy and corresponding radiocarbon ages in soils, sediments and dissolved organic carbon. We find that activation energy distributions broaden over time in all mineral-containing samples. This result requires increasing bond-strength diversity, consistent with the formation of organo-mineral bonds8 but inconsistent with selective preservation. Radiocarbon ages further reveal that high-energy, mineral-bound organic carbon persists for millennia relative to low-energy, unbound organic carbon. Our results provide globally coherent evidence for the proposed7 importance of mineral protection in promoting organic carbon preservation. We suggest that similar studies of bond-strength diversity in ancient sediments may reveal how and why organic carbon preservation-and thus atmospheric composition and climate-has varied over geological time.

Social behaviour and collective motion in plant-animal worms.

Social behaviour may enable organisms to occupy ecological niches that would otherwise be unavailable to them. Here, we test this major evolutionary principle by demonstrating self-organizing social behaviour in the plant-animal, Symsagittifera roscoffensis. These marine aceol flat worms rely for all of their nutrition on the algae within their bodies: hence their common name. We show that individual worms interact with one another to coordinate their movements so that even at low densities they begin to swim in small polarized groups and at increasing densities such flotillas turn into circular mills. We use computer simulations to: (i) determine if real worms interact socially by comparing them with virtual worms that do not interact and (ii) show that the social phase transitions of the real worms can occur based only on local interactions between and among them. We hypothesize that such social behaviour helps the worms to form the dense biofilms or mats observed on certain sun-exposed sandy beaches in the upper intertidal of the East Atlantic and to become in effect a super-organismic seaweed in a habitat where macro-algal seaweeds cannot anchor themselves. Symsagittifera roscoffensis, a model organism in many other areas in biology (including stem cell regeneration), also seems to be an ideal model for understanding how individual behaviours can lead, through collective movement, to social assemblages.

Mesenteric Infarction: Clinical Outcomes After Restoration of Bowel Continuity.

INTRODUCTION: Patients who have a bowel resection for mesenteric infarction may require parenteral nutrition (PN). This study primarily aimed to determine the aetiological factors for a mesenteric infarction and the effects of restoring bowel continuity on the long-term PN requirements. METHODS: A retrospective review of data on patients treated for mesenteric infarction from 2000 to 2010. RESULTS: A total of 113 patients (61 women, median age 54 years) were identified. Seventy-four (65%) had a superior mesenteric artery thromboembolism, 25 (22%) had a superior mesenteric vein thrombosis, and 4 (3%) had superior mesenteric artery stricture or spasm. Patients younger than 60 years most commonly had a clotting abnormality (n = 23/46, 50%), whereas older patients had a cardiological risk factor (n = 11/17, 65%). All patients with a jejunostomy required long-term PN. Fifty-seven (49%) patients had restoration of bowel continuity (colon brought into circuit). After this, PN was stopped within 1 year in 20 (35%), within 2 years in 29 (50%) patients and within 5 years in 44 (77%) patients (P = 0.001). CONCLUSIONS: A thrombotic tendency is the main etiological factor in most patients younger than 60 years. An anastomosis of the remaining jejunum to the colon can allow PN to be stopped.

The epidemiology of pediatric patients seen at the Children's Hospital of Oklahoma with laboratory confirmed influenza in 2009.

CONTEXT: In 2009, a new strain of influenza A, subtype H1N1, infected otherwise healthy children with increased rate of hospitalization. STUDY OBJECTIVE: To document the type of influenza infection, identify those pediatric patients at risk for complications, compare those patients requiring hospital admission to those discharged, and examine the use of antiviral/antibiotic medications. METHODS: We conducted a retrospective chart review of patients 0-18 years, in 2009 that tested positive at Children's Hospital for influenza. Type of influenza, initial presentation, secondary complications, underlying co-morbidities, hospitalization, death, antiviral and antibiotic prescribing practices were recorded. RESULTS: Two hundred and eighty-seven patients tested positive. Two hundred and twelve were influenza A, H1N1 subtype, 55 were Influenza A, not subtyped and 20 were influenza B. One hundred and twenty-eight of our study patients were hospitalized (44%). One hundred and three patients were positive for H1N1, for a hospitalization rate of 47%, Fifteen percent of the study population required Intensive care support. Caucasian patients and those having chronic medical conditions were more likely to require hospitalization. Early antiviral therapy was associated with a better outcome. CONCLUSION: The majority of children with influenza in 2009 had the novel H1N1 strain. Almost half of study patients were hospitalized. Patients with underlying medical problems were more likely to be hospitalized. The majority of hospitalized patients had good outcomes.

Size-dependent Pb sorption to nanohematite in the presence and absence of a microbial siderophore.

This study focused on the effects of particle size (40, 8.6, and 3.6 nm) and the presence of the microbial ligand desferrioxamine B (DFOB) on Pb(II) sorption to hematite, based on sorption edge experiments (i.e., sorption as a function of pH). Effects of hematite nanoparticle size on sorption edges, when plotted either as sorption density or as % Pb uptake, depended on whether the experiments were normalized to account for differences in specific surface area within the reaction vessels or postnormalized after the fact. Accounting for specific surface area within reaction vessels is needed to maintain comparable ratios of sorbate to sorbent surface sites. When normalized for BET specific surface area (A(s,BET)) within the reaction vessels, the Pb(II) sorption edge shifted ∼0.5 pH units to the left for <10 nm hematite particles, but maximum sorption density (at pH ≥ 6) was unaffected by particle size. DFOB had little or no effect on Pb(II) sorption to <10 nm particles, but DFOB decreased Pb(II) sorption to the 40 nm particles at pH ≥ 6 by ∼20%. Hematite (nano)particle size thus exerts subtle effects on Pb(II) sorption, but the effects may be more pronounced in the presence of a metal complexing agent.

Altered endothelin receptor subtypes in colorectal cancer.

BACKGROUND: The vasoactive peptide endothelin-1 (ET-1) acts via two endothelin receptor subtypes, ETA (ETAR) and ETB (ETBR). ET-1 and ETAR are overexpressed in colorectal cancer tissues. In vitro, ET-1 acting via ETAR, is a mitogen for colorectal cancer cells. To identify other potential stimulatory loops, we investigated the distribution and cell-specific localization of both ETAR and ETBR in tissue sections from patients with colorectal cancer. METHODS: Frozen sections from specimens of colorectal cancer (n=9) and normal colon (n=9) were cut and subjected to either (i) autoradiography or (ii) a combination of cell type-specific immunohistochemistry, using antibodies against fibroblasts (AS02), endothelial cells (CD31) or nerve fibres (NF200) and in-vitro receptor microautoradiography, using ETAR-specific and ETBR-specific radioligands. RESULTS: ETARs were upregulated in all cell types, apart from nerve, in cancer compared with normal colon (1:1.59 normal to cancer). Specifically, ETAR binding was highest in cancer-associated blood vessels and fibroblasts and to a lesser extent in epithelial cancer cells. In contrast, ETBRs were the predominant receptors in normal colon (1:0.59 normal to cancer) and were markedly down-regulated in cancer-associated blood vessels, fibroblasts and to a lesser extent in epithelial cells. Nerve colocalization was demonstrated, but remained unchanged for all tissues. CONCLUSION: The shift in ET receptor binding observed in epithelial cancer cells and cancer-associated fibroblasts and endothelial cells may favour ET-1 signals contributing to colorectal cancer growth and neovascularization via ETAR. This may provide the basis for therapeutic use of specific ETAR antagonists as adjuvant treatment of colorectal cancer.

Colorectal cancer in the young patient.

Colorectal cancer is the second most common cause of death from cancer in the UK. It is estimated that between 2 to 3 per cent of colorectal cancer occurs in patients younger than the age of 40 years. It remains unclear from the literature whether this group of patients has a worse prognosis from colorectal cancer than the population as a whole. There are no large series that report a 10-year survival in young patients diagnosed with colorectal cancer. The authors' objective was to assess patients diagnosed with colorectal cancer younger than the age of 40 years to determine whether the 5- and 10-year survival rates in a tertiary referral center compares favorably with survival rates obtained at other centers and the population as a whole. A retrospective observational study was conducted and an analysis of the patient's notes was made, specifically looking at age at diagnosis, nature and duration of symptoms, predisposing risk factors for colorectal cancer, the site within the bowel of the colorectal cancer, the type of curative resection performed, Dukes' stage, and details of 5- and 10-year follow-up to assess survival. Forty-nine patients age 40 years or younger received treatment for colorectal cancer at St. Mark's Hospital from 1982 to 1992. The overall 5- and 10-year survival was 58 per cent and 46 per cent respectively. The study provides more evidence to support the fact that young patients with colorectal cancer seem to present with more advanced disease. Despite this, the overall 5-year relative survival rate is comparable if not better than other studies, supporting recent evidence that the prognosis in this group of patients is no worse than for colorectal cancer in the population as a whole.

Destabilization of phospholipid model membranes by YplA, a phospholipase A2 secreted by Yersinia enterocolitica.

Yersinia enterocolitica produces a virulence-associated phospholipase A(2) (YplA) that is secreted via its flagellar type-III secretion apparatus. When the N-terminal 59 amino acids of YplA are removed (giving YplA(S)), it retains phospholipase activity; however, it is altered with respect to the apparent kinetics of hydrolysis using fluorescent phospholipid substrates in micellar form. To explore the physical properties of YplA more carefully, Langmuir phospholipid monolayers were used to study the association of YplA with biological membranes. YPlA and YplA(S) both associate with Langmuir monolayers, but YplA(S) appears to interact better at low initial lipid densities while YplA interacts better at higher densities. This may indicate that the N-terminus of YplA has a role in mediating its initial interaction with compact cellular membranes, which is consistent with spectroscopic observations that fluorescein-labeled YplA may interact more readily with the nonpolar region of liposomes than does YplA(S).

Determinants of iodothyronine deiodinase activities in rodent uterus.

The deiodinase types 2 and 3 (D2, D3), which convert T4 to active and inactive metabolites, respectively, are expressed in the rodent uterus and highly induced during pregnancy. To examine the factors regulating the expression of these enzymes in this tissue, we studied D2 and D3 activity in pregnant rats, in pseudopregnant rats before and after the induction of artificial decidualization, and in ovariectomized rats treated with 17beta-estradiol (E2) and/or progesterone (P). Our results demonstrate that induction of D3 activity begins immediately after implantation and increases markedly over the next 72 h. A similar time course and magnitude of D3 induction is noted in the artificially decidualized uterus in pseudopregnant rats, whereas only minimal increases in activity are observed in the nondecidualized control uterine horns in the same animal. In contrast, D2 activity is not induced by a decidualization stimulus. In spontaneously cycling female rats, both D2 and D3 were observed to be 3- to 8-fold higher in proestrus, compared with diestrus. Furthermore, levels of D2 and D3 activity were greatly increased in ovariectomized rats given E2 and P in various combinations. D2 activity was stimulated primarily by E2, whereas E2 and P acted synergistically to increase D3 activity. These results demonstrate that E2 and P regulate thyroid hormone metabolism in the uterus, and that the implantation process is a potent stimulus for the induction of D3 activity in this organ. Such precise and profound changes in deiodinase expression are likely to play important physiological roles in fetal development and may influence uterine function.

Effect of mouse uterine stromal cells on epithelial cell transepithelial resistance (TER) and TNFalpha and TGFbeta release in culture.

Recognizing that uterine stromal cells regulate several uterine epithelial cell function(s), the current study was undertaken to more fully define cell-cell communication in the uterus and to examine the role of uterine stromal cells in regulating epithelial cell monolayer integrity and cytokine release. Uterine epithelial and stromal cells from adult intact mice were isolated and cultured separately on cell culture inserts and/or in culture plates. Epithelial cells, which reach confluence as indicated by high transepithelial resistance (TER > 1000 ohms/well), preferentially release transforming growth factor-beta (TGFbeta) into the basolateral chamber ( approximately 70% > apical) and tumor necrosis factor-alpha (TNFalpha) into the apical compartment ( approximately 30% > basolateral). When epithelial cells on cell culture inserts were transferred to plates containing stromal cells, coculture for 24-48 h increased epithelial cell TER ( approximately 70% higher than control) and decreased TNFalpha release into both the apical and basolateral chambers ( approximately 30%-50%). In contrast, TGFbeta release was not affected by the presence of stromal cells. In other studies, the effects of stromal cells on epithelial cell TER and TNFalpha release persisted for 5-7 days following the removal of stromal cells and were also seen in coculture studies in which conditioned stromal media (CSM) was placed in the basolateral chamber. These studies indicate that uterine stromal cells produce a soluble factor(s) that regulates epithelial cell TER and release of TNFalpha without effecting TGFbeta release. These results suggest that uterine stromal cells communicate with epithelial cells via a soluble factor(s) to maintain uterine integrity and epithelial secretory function.