Anaphylaxis reaction to Samsum ant (Pachycondyla sennaarensis): a case series study

Summary

Background. Anaphylaxis is a life-threatening hypersensitivity reaction. The present study aimed to investigate the cases of anaphylaxis to ant stings in Iran to determine the characteristics of patients, geographical distribution and the type of ants that cause anaphylaxis. Methods. Patients with a history of anaphylaxis to ant sting underwent skin allergy test with extracted substance from Solenopsis invicta. Samples of ants were collected from the sites where each patient was bitten and their species were identified by a medical entomologist. Results. Nineteen patients (mean age: 26.2 years; range: 4-48 years) were included in the study. Most patients (89.5 percent) were female. The lower limb was the most common site of the sting and most stings had occurred in the morning (31.6 %) and evening (31.6%). Skin manifestations were the most common clinical symptoms (94.7%). Most cases of stings were observed in the Hormozgan province (89.5%) located in southern Iran. Sixteen patients had positive skin prick test for ant venom. All collected ants that caused anaphylaxis belonged to the Pachycondyla sennaarensis species. Conclusions. Ant sting anaphylaxis is not uncommon in Iran, especially in its southern regions. All cases of anaphylaxis in this study were due to samsum ant sting (Pachycondyla sennaarensis), which is a species similar to the fire ant (Solenopsis invicta). Allergy skin testing with fire ant extract was positive and helpful in identifying samsum ant allergy in all cases.

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

Hot and cold executive functions in pure opioid users undergoing methadone maintenance treatment: Effects of methadone dose, treatment duration, and time between last methadone administration and testing

CONTEXT

Methadone maintenance is a standard treatment for opiate-dependent individuals. However, deficits in cognitive functioning have been associated with this treatment.

AIM

This study aimed to determine the dose and treatment duration-related effects of methadone on executive functions.

SETTING AND DESIGN

Pure male opioid users with no considerable history of other drug abuse, undergoing methadone maintenance treatment (MMT) were recruited from a major government-run de-addiction center.

METHODS

Hot executive functions including decision-making and emotion recognition were assessed using the Iowa gambling task and Ekman faces test, whereas cold executive functions including working memory (WM), cognitive flexibility, and response inhibition were assessed using n-back, Wisconsin card sorting test, and the GO/NOGO task, respectively. Statistical Analyses Used: Descriptive statistics, Pearson's correlation coefficients, and multiple regression analysis were used to test the hypotheses of the study.

RESULTS

Methadone dose and length of MMT were found to be associated with greater impairment in executive functions. Impairment in cognitive performance was also found to be inversely related to time since dosing. Regression analyses revealed that methadone dosage and time since dosing accounted for a significant proportion of the variance in cognitive flexibility, while the total amount of methadone administered was able to predict deficits in WM, methadone treatment duration predicted psychomotor speed, and time since dosing predicted decision-making ability.

CONCLUSIONS

To keep cognitive impairment at a minimum, methadone dose and treatment duration will have to be customized considering the history of opiate abuse so that impairment attributable to long-term opiate use may be differentiated from acute methadone dosing.

Oral complications at 6 months after radiation therapy for head and neck cancer

OBJECTIVE

To examine oral complications 6 months after modern radiation therapy (RT) for head and neck cancer (HNC).

METHODS

Prospective multicenter cohort study of patients with HNC receiving intensity-modulated radiation therapy or more advanced RT. Stimulated whole salivary flow, maximal mouth opening, oral mucositis, oral pain, oral health-related quality of life (OH-QOL), and oral hygiene practices were measured in 372 subjects pre-RT and 216 subjects at 6 months from the start of RT.

RESULTS

Mean stimulated whole salivary flow declined from 1.09 to 0.47 ml/min at 6 months (p < .0001). Mean maximal mouth opening reduced from 45.58 to 42.53 mm at 6 months (p < .0001). 8.1% of subjects had some oral mucositis at 6 months, including 3.8% with oral ulceration. Mean overall pain score was unchanged. OH-QOL was reduced at 6 months, with changes related to dry mouth, sticky saliva, swallowing solid foods, and sense of taste (p ≤ .0001). At 6 months, there was greater frequency of using dental floss and greater proportion using supplemental fluoride (p < .0001).

CONCLUSIONS

Despite advances in RT techniques, patients with HNC experience oral complications 6 months after RT, with resulting negative impacts on oral function and quality of life.

EFFECT OF TIME EXPOSURE ON THERMOLUMINESCENCE GLOW CURVE FOR UV-INDUCED ZRO2:MG PHOSPHOR

In this research, the effect of magnesium (Mg) impurity on thermoluminescence (TL) response of ZrO2 phosphors is studied experimentally. In the experimental procedure, ZrO2:Mg phosphors in the powder form were synthesised by the sol-gel method. The obtained hydrogel was dried in air and then calcinated in air at 1200°C for 5 h and next was annealed at 250°C for 2 h. Sample characterisations were done by X-ray diffraction and scanning electron microscopy. Obtained materials had monoclinic phase and porous microstructure. Then, known amounts of ZrO2:Mg powder were exposed to ultraviolet lamp from 0.5 to 120 min. The TL peaks were obtained at the same temperature as 75, 137 and 260°C, respectively. Adding Mg to pure zirconia caused to increase TL intensity and shift peaks related to pure zirconia. The TL peaks of the pure zirconia were seen at the 83, 132 and 235°C. Finally, ZrO2:Mg TL experimental results show the linear dose response, high stability and less fading.

Role of protein kinase C in the signal pathways that link Na+/K+-ATPase to ERK1/2

We have shown before that Na(+)/K(+)-ATPase acts as a signal transducer, through protein-protein interactions, in addition to being an ion pump. Interaction of ouabain with the enzyme of the intact cells causes activation of Src, transactivation of EGFR, and activation of the Ras/ERK1/2 cascade. To determine the role of protein kinase C (PKC) in this pathway, neonatal rat cardiac myocytes were exposed to ouabain and assayed for translocation/activation of PKC from cytosolic to particulate fractions. Ouabain caused rapid and sustained stimulation of this translocation, evidenced by the assay of Ca(2+)-dependent and Ca(2+)-independent PKC activities and by the immunoblot analysis of the alpha, delta, and epsilon isoforms of PKC. Dose-dependent stimulation of PKC translocation by ouabain (1-100 microm) was accompanied by no more than 50% inhibition of Na(+)/K(+)-ATPase and doubling of [Ca(2+)](i), changes that do not affect myocyte viability and are known to be associated with positive inotropic, but not toxic, effects of ouabain in rat cardiac ventricles. Ouabain-induced activation of ERK1/2 was blocked by PKC inhibitors calphostin C and chelerythrine. An inhibitor of phosphoinositide turnover in myocytes also antagonized ouabain-induced PKC translocation and ERK1/2 activation. These and previous findings indicate that ouabain-induced activation of PKC and Ras, each linked to Na(+)/K(+)-ATPase through Src/EGFR, are both required for the activation of ERK1/2. Ouabain-induced PKC translocation and ERK1/2 activation were dependent on the presence of Ca(2+) in the medium, suggesting that the signal-transducing and ion-pumping functions of Na(+)/K(+)-ATPase cooperate in activation of these protein kinases and the resulting regulation of contractility and growth of the cardiac myocyte.

Differential alterations in cardiac adrenergic signaling in chronic hypoxia or norepinephrine infusion

Norepinephrine (NE)-induced desensitization of the adrenergic receptor pathway may mimic the effects of hypoxia on cardiac adrenoceptors. The mechanisms involved in this desensitization were evaluated in male Wistar rats kept in a hypobaric chamber (380 Torr) and in rats infused with NE (0.3 mg. kg(-1). h(-1)) for 21 days. Because NE treatment resulted in left ventricular (LV) hypertrophy, whereas hypoxia resulted in right (RV) hypertrophy, the selective hypertrophic response of hypoxia and NE was also evaluated. In hypoxia, alpha(1)-adrenergic receptors (AR) density increased by 35%, only in the LV. In NE, alpha(1)-AR density decreased by 43% in the RV. Both hypoxia and NE decreased beta-AR density. No difference was found in receptor apparent affinity. Stimulated maximal activity of adenylate cyclase decreased in both ventricles with hypoxia (LV, 41%; RV, 36%) but only in LV with NE infusion (42%). The functional activities of G(i) and G(s) proteins in cardiac membranes were assessed by incubation with pertussis toxin (PT) and cholera toxin (CT). PT had an important effect in abolishing the decrease in isoproterenol-induced stimulation of adenylate cyclase in hypoxia; however, pretreatment of the NE ventricle cells with PT failed to restore this stimulation. Although CT attenuates the basal activity of adenylate cyclase in the RV and the isoproterenol-stimulated activity in the LV, pretreatment of NE or hypoxic cardiac membranes with CT has a less clear effect on the adenylate cyclase pathway. The present study has demonstrated that 1) NE does not mimic the effects of hypoxia at the cellular level, i.e., hypoxia has specific effects on cardiac adrenergic signaling, and 2) changes in alpha- and beta-adrenergic pathways are chamber specific and may depend on the type of stimulation (hypoxia or adrenergic).

Fenspiride and membrane transduction signals in rat alveolar macrophages

Fenspiride inhibits the calcium signal evoked by the inflammatory peptide formyl-Met-Leu-Phe (fMLP) in peritoneal macrophages, but at concentrations (approximately 1 mM) far above the therapeutic range (approximately 1 microM). Here, in rat alveolar macrophages, high fenspiride concentrations (1 mM) were required to inhibit the calcium signals evoked by the calcium agonist Bay K8644 or by ionomycin. Moreover, fenspiride (1 mM) was a poor inhibitor of the cell membrane depolarization induced by gramicidine D. By contrast, fenspiride blocked Na+-H+ antiport activation by (i) fMLP with an IC50 = 3.1 +/- 1.9 nM and (ii) PMA (phorbol 12-myristate 13-acetate) with an IC50 = 9.2 +/- 3.1 nM. Finally, protein kinase C (PKC) activity of macrophage homogenate was not significantly modified by 10 or 100 microM fenspiride (at 100 microM: 2.57 +/- 1.60 vs. 2.80 +/- 1.71 pmol/10(6) cells/min). In conclusion, fenspiride inhibits fMLP- and PMA-induced pH signals in rat alveolar macrophages, probably by acting distally on the PKC transduction signal. This pH antagonistic action may be relevant for the antiinflammatory mechanism of fenspiride and requires further investigation.

Protein kinase C activity and expression in rabbit left ventricular hypertrophy

Protein Kinase C (PKC) is implicated in the induction of myocardial hypertrophy. Recent studies showed an increased activity and expression of PKC in rat left ventricular hypertrophy, but we demonstrated a decreased PKC activity and content in rabbit heart failure. The present study was designed to evaluate whether these differences were due to species or model differences. PKC activity and expression were measured in a model of mild ventricular overload, induced by a 40-50% constriction of the abdominal aorta in rabbits. Left ventricular (LV) weight/body weight ratio was increased by 14, 21 and 36% after 4, 18 and 42 days of stenosis, respectively. PKC activity was significantly decreased after 18 and 42 days of stenosis in the particulate fraction of LV, but it was not modified in the cytosolic fraction leading to a significantly decreased translocation index (particulate/total activity ratio): 18.6 +/- 2.2% and 19.4 +/- 1.6% at 18 days and 42 days of aortic stenosis, respectively, compared with 25.7 +/- 2.0% and 25.8 +/- 1.2% in corresponding sham-operated rabbits (both Ps < 0.05). Similarly, PKC content, measured by immunoblotting, was not modified in the cytosolic fractions, but decreased significantly in the particulate fractions after 18 and 42 days of stenosis. These data are, thus, different from those obtained in rat LV hypertrophy showing species differences in PKC expression in hypertrophy. They also show that hypertrophy may take place without induction of PKC.

Protein kinase C isoform expression in normal and failing rabbit hearts

Protein kinase C (PKC) is activated by alpha-adrenergic stimulation. Molecular analysis showed that PKC consists of a family of at least 12 isozymes. Studies of their distribution in the heart showed conflicting results. The first goal of our study was thus to characterize cardiac PKC in normal rabbits. PKC plays an important role in gene expression, cell growth, and differentiation and is involved in the hypertrophy phase of cardiac overload, but since its expression has never been evaluated in heart failure, the second goal of our study was to evaluate PKC activity and isoform expression in rabbits with heart failure induced by a double hemodynamic overload (aortic insufficiency followed by an aortic stenosis). In the first part of the study, PKC isoform expression analyzed in normal rabbits by immunoblotting showed that isoforms alpha, beta, epsilon, and zeta were expressed along with PKC gamma, which had never been detected in the heart. PKC gamma expression was also identified by polymerase chain reaction, and immunofluorescence techniques showed a localization on intercalated disks associated with the membrane localization observed with the other isoforms. In the second part of the study, PKC activity, content, and isoform expression showed a decrease of 37% in the failing group. PKC immunodetection with a monoclonal antibody (Mab 1.9) recognizing the catalytic domain of all PKC isoforms revealed a 20% decrease in the failing ventricles compared with normal left ventricles. Expressed PKC isoforms quantified by Western blot showed, in the failing heart group compared with the control group, a decrease of 27%, 32%, 16%, and 9% of PKC alpha, PKC beta 1, PKC gamma, and PKC epsilon, respectively, whereas PKC zeta was not significantly modified. These results show that, in heart failure, PKC activity and expression of Ca(2+)-dependent PKC isoforms are decreased. This may lead to alterations of PKC-induced phosphorylations.