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.

Drought stress enhances the efficiency of floral dip method of Agrobacterium-mediated transformation in Arabidopsis thaliana

The Agrobacterium-mediated floral dip protocol is the most extensively used transformation method for a model plant Arabidopsis thaliana. Several useful methods for Agrobacterium tumefaciens-mediated transformations of Arabidopsis are existing, but they are time consuming and with low transformation efficiency. Here, we developed a transgenic Arabidopsis lines TET12p::TET12-RFP in a short period of time and enhanced transformation efficiency by using a modified transformation method by applying drought stress after floral dip. In this protocol, Agrobacterium cells carrying TET12p::TET12-RFP recombinant vectors were resuspended in a solution of 5% sucrose, 0.05% (v/v) silwet L-77 to transform female gametes of developing Arabidopsis inflorescences. Treated Arabidopsis were then applied with different levels of drought stresses to stimulate plants for the utilization of maximum plant energy in seed maturation process. The applied stresses achieved the fast maturation of already treated inflorescences while stopped the growing of newly arising untreated inflorescence, thus decreased the chances of wrong collection of untransformed seeds. Consequently, the collected seeds were mostly transgenic with a transformation frequency of at least 10%, thus the screening for positive transformants selection was more advantageous on a selective medium as compared to a classical floral dip method. Within 2-3 months, two hundred of individual transgenic plants were produced from just 10 infiltrated plants. This study concludes that application of drought stresses in a specific stage of plant is a beneficial strategy for achieving the transgenic Arabidopsis in a short period of time with high transformation efficiency.

Composition and structure of plant communities in the Moist Temperate Forest Ecosystem of the Hindukush Mountains, Pakistan

Abstract Here, we investigated the relationship between Plant communities and the environment from the moist temperate vegetation of Lakoo mountainous forest District Swat. We sampled data from 162 sampling units (Quadrates) using 1x1m2 for herbs 5x5m2 and shrubs, while 10 x10m2 for trees, systematically considering six elevation gradients between the altitudinal from 1970m to 3095m. We performed statistical analysis like Canonical correspondence analysis (CCA) and TWINSPAN (two-way indicator species analysis) for ecological assessment and clustering of plant communities. To check upon the correlation of species (CR) with topographic and edaphic variables we used statistical software PC-ORD version 7. We recognized 264 species plants belonging to thirty families. We recorded key sampling measurements of density, frequency, and cover for all these species which are vital for community description. The results showed Shannon-Winner,s, and Simpson diversity values as 19.18 and 3.17 respectively. The importance value indexes (IVI) were used to identify the leading and rare species of plant in each community or cluster group. In total we recognized eleven different communities as: Berberis- Abies- Bergeni, Picea - Indigofera- Poa,Abies- Parrotiopsis- Poa, Quercus- Viburnum- Poa, Picea- Salix- Primula, Abies- Viburnum- Poa, Viburnum- Taxus- Poa, Pinus- Viburnum- Lithospermum, Abies-Berberis- carex, Pinus- Viburnum- Poa and Parrotiopsis- Picea- Poa through hierarchical cluster analysis (TWINSPAN). CCA analysis revealed that of all studied edaphic and topographic variables altitude, silt, calcium carbonate, and organic matter were the strongest factors determining plant community diversity and composition in each microclimate of the eleven communities. Visually the vegetation of the forest was dominated by small-sized trees followed by shrubs, and regenerates indicating the stage of secondary regeneration. We found severe human interference in disturbing the existing biodiversity, which requires immediate conservation to ensure sustainable management and utilization of natural resources of the Lalkoo moist temperate forest.

Diversity of the Anisoptera & Zygoptera (Odonata: Insecta) of Swat, Pakistan

Odonates are important biological control agents for the control of insect pests and insect disease vectors of medical and veterinary importance. The present study was conducted to evaluate the odonate fauna of Swat, Pakistan from March to October 2019. A total of 200 specimens of odonates were collected from diverse habitats. The collected specimens of the order Odonata belonged to 5 families, three families of suborder Anisoptera namely Libellulidae, Gomphidae and Aeshnidae while two families of suborder Zygoptera (Chlorocyphidae and Coenagrionidae). The specimens were categorized into 12 genera and 22 species. Libellulidae was the dominant family (n = 138) accounting for 69% of the odonate fauna. Orthetrum was the dominant genus (n = 73) of suborder Anisoptera accounting for 36.5% of the odonate fauna. The least dominant genera were Anax, Paragomphus and Rhyothemis (n = 5 each) accounting each for 2.5% of the odonate fauna. In Zygoptera, the dominant genus was Ceriagrion (12.5%) and the least dominant genus was Ischnura (6%). Pantala flavescens (Fabricius, 1798) was the most abundant odonate species in the study area recorded from all surveyed habitats. Shannon Diversity Index (H) was 2.988 and Simpson Diversity Index (D) was 0.95 for the collected odonate fauna. The highest abundance of Odonata was recorded in August, September and May while no odonate species were recorded in January, February, November and December. Lotic water bodies were the most suitable habitats with abundant odonate fauna. Anax immaculifrons (Rambur, 1842) was the largest sized odonate species having a wingspan of 53.2±1.63 mm and body length of 56.3 ± 0.4 mm. The present study shows the status of odonate fauna of Swat, Pakistan in diverse habitats and seasonsonal variation throughout the year. Further work is recommended to bridge the gaps in the existing literature.

Honey as a bioindicator of environmental organochlorine insecticides contamination

Honey is a suitable matrix for the evaluation of environmental contaminants including organochlorine insecticides. The present study was conducted to evaluate residues of fifteen organochlorine insecticides in honey samples of unifloral and multifloral origins from Dir, Pakistan. Honey samples (5 g each) were extracted with GC grade organic solvents and then subjected to Rotary Evaporator till dryness. The extracts were then mixed with n-Hexane (5 ml) and purified through Column Chromatography. Purified extracts (1μl each) were processed through Gas Chromatograph coupled with Electron Capture Detector (GC-ECD) for identification and quantification of the insecticides. Of the 15 insecticides tested, 46.7% were detected while 53.3% were not detected in the honey samples. Heptachlor was the most prevalent insecticide with a mean level of 0.0018 mg/kg detected in 80% of the samples followed by β-HCH with a mean level of 0.0016 mg/kg detected in 71.4% of the honey samples. Honey samples from Acacia modesta Wall. were 100% positive for Heptachlor with a mean level of 0.0048 mg/kg followed by β-HCH with a mean level of 0.003 mg/kg and frequency of 83.3%. Minimum levels of the tested insecticides were detected in the unifloral honey from Ziziphus jujuba Mill. Methoxychlor, Endosulfan, Endrin and metabolites of DDT were not detected in the studied honey samples. Some of the tested insecticides are banned in Pakistan but are still detected in honey samples indicating their use in the study area. The detected levels of all insecticides were below the Maximum Residue Levels (MRLs) and safe for consumers. However, the levels detected can cause mortality in insect fauna. The use of banned insecticides is one of the main factors responsible for the declining populations of important insect pollinators including honeybees.

Habitat selection by Asiatic black bear (Ursus thibetanus) in Siran and Kaghan Valleys, Pakistan

Asiatic black bear is present in variety of habitats like broad-leaves and coniferous forests, extending form sea level to 4300m elevation and change their habitat for food purpose seasonally. The present study was conducted at Kaghan and Siran Valleys, District Mansehra, Khyber Pakhtunkhwa, Pakistan to assess habitat of black bear. Line transect method was used for observation of bear signs. Twelve meter circular radius plots were selected for the concern vegetation's i.e. (trees, shrubs and herbs) and three to six plots were placed in each transect. At the result of sign survey, thirteen different categories of bear signs were recorded and encounter rate was calculated for each sign. A total of 1858 signs were observed during field surveys. Total (81%) coniferous species were recoded among trees, with the highest appearance of Pinus wallichiana (34.22%) and Spruce spp (27.76%), similarly broad leaves trees (18.56%) were also recoded from habitat plots. Most of the signs were encountered in bushy areas, whereas high number of Viburnum Spp (60.29%) was present. It is indicated that black bear prefers blend of Coniferous Trees, Viburnum and Ferns Species; probably because these plants provide enough food, protection, and meticulous shelter because more than 80% of habitat composed of these three species. Currently habitat destruction and increase in human population are the up-growing issues for wild animals (especially Asiatic black bear), which is highly sensitive to such problems. High levels of conservation efforts are recommended for the protection of black bear habitat and to avoid human interference in their territory.

Diversity, distribution and relative abundance of the mosquito fauna (Diptera: Culicidae) of Malakand and Dir Lower, Pakistan

The present study was conducted to evaluate the diversity, distribution (C) and relative abundance (RA) of the mosquito fauna (Diptera: Culicidae) of Malakand and Dir Lower, Pakistan. Collection of specimens (n = 1087) was made during September 2018 to July 2019 at six different habitats including freshwater bodies, rice fields, animal sheds, indoors, drains and sewage waters. Specimens were collected through light traps, pyrethrum spray, aspirators and nets and subsequently killed, preserved and then arranged in entomological boxes for identification. Three genera were identified namely Culex, Anopheles and Aedes. A total of fourteen species were identified namely: Cx. quinquefasciatus (Say, 1823), An. stephensi (Liston, 1901), Cx. tritaeniorhynchus (Giles, 1901), Ae. vittatus (Bigot, 1861), An. maculatus (Theobald, 1901), An. fluviatilis (James, 1902), Cx. vishnui (Theobald, 1901), Ae. aegypti (Linnaeus, 1762) An. subpictus (Grassi, 1899), An. dthali (Patton, 1905), An. culicifascies (Giles, 1901), An. pallidus (Theobald, 1901), Ae. albopictus (Skuse, 1894) and An. annularis (van der Wulp, 1884). Cx. quinquefasciatus was found constantly distributed in the study area with RA = 16.5% and C = 100%. An. annularis was found as a satellite species, sporadically distributed in the study area having RA = 0.9% and C = 17%. Diversity indices of mosquitoes in the studied habitats were found as, Shannon-Wiener Index (2.415), Simpson Index (9.919), Fisher's Index (2.269) and Margalef's Index (1.859). A statistically significant difference was recorded in mosquito diversity in the six habitats (Kruskal-Wallis, chi-squared, H = 17.5, df = 5, P = 0.003 at α = 0.05). The present study encompasses mosquito fauna of Malakand, Pakistan with respect to diversity, relative abundance and distribution in diverse habitats and all seasons of the year. This will assist scientists working in various fields related with epidemiology, medical and veterinary entomology, ecology and allied areas of biological sciences.

Population distribution and habitat analysis of Rufous treepie (Dendrocitta vagabunda) in Abbottabad, Pakistan

The Rufous treepie (Dendrocitta vagabunda) belongs to family corvidae, order Passeriformes which includes about 100 species. The current study was conducted to gather information about the Population distribution and habitat analysis of D. vagabunda at District Abbottabad, Pakistan. The data were collected on monthly basis both morning and evening times (2018-2019). "The ''Point count Method" was used for population estimation and ''Quadrates Method" for habitat analysis of study area. The result shows an average month-wise population density of D. vagabunda was maximum at Jhangra 0.14±0.039/ha, whereas minimum at Havelian 0.11±0.022/ha. There was no significant difference (p>0.05) among monthly population densities of D. vagabunda, however, a significant difference (p<0.05) was found between morning and evening times population of the specie. The present study revealed that importance value index (IVI) of plants species at Sherwan, Bakot, Havelian, Langra and Jhangra were 59.6±12.6, 50.1±6.9, 53.4±6.3, 66.8±10 and 60.1±7.7. Likewise, the frequency of shrubs at Sherwan, Bakot, Havelian, Langra and Jhangra were 33.3±4.2, 45±9.4, 46.7±8.2, 55.6±22.2 and 37.5±8.5. Similarly, the frequency of herbs at Sherwan, Bakot, Havelian, Langra and Jhangra were 40.4±6.0, 37.5±5.6, 53.3±7.4, 48.5±5.2 and 46.9±7.4 respectively. Our results show the study area as suitable habitat for D. vagabunda.

Influence of low-protein and low-amino acid diets with different sources of protease on performance, carcasses and nitrogen retention of broiler chickens

A 42-day experiment was conducted with 625 1-day-old male Hubbard chickens to evaluate the performance, carcass traits, nitrogen retention and economics of broiler chickens fed low protein and amino acid diets supplemented with different protease sources. Treatments included positive (PC) and negative (NC) controls (PC at 19.3% protein vs NC at 18.8% protein), with NC containing 7% less digestible amino acids. The other three treatment groups were based on the NC diet supplemented with 0.05% Cibenza® DP100 (CB), 0.02% Ronozyme® (RZ) or 0.02% Winzyme pro plus (WZ). Birds fed the PC, CB and WZ diets achieved the heaviest bodyweight compared with those fed the NC diet at end of the experiment. Total feed intake of birds fed the PC diet was higher (P < 0.05) than that of birds fed the NC diet. Feed conversion ratio was numerically significantly (P = 0.005) improved with all tested groups in comparison with NC throughout the experiment. European production index was similar (P > 0.05) among birds fed the PC, NC, RZ or WZ diets. All carcass parameters studied, including dressing, heart, gizzard, giblets, chest meat, thigh meat and abdominal fat percentages, were not significantly (P > 0.05) affected by feeding on the different sources of protease. Broilers fed the PC diet or diets formulated with all protease sources had higher (P < 0.05) nitrogen retention than did birds fed the NC diet. The supplementation of protease to low-protein and low-amino acid diets resulted in higher profit margin in broilers. It is concluded that supplementing exogenous protease to broiler diets containing low protein and amino acids improved the growth performance, feed utilisation, carcass traits, nitrogen retention and net returns of broiler chickens.

Effect of graded levels of dietary corn steep liquor on growth performance, nutrient digestibility, haematology and histopathology of broilers

This experiment was conducted to assess nutritional potential of corn steep liquor (CSL) as an alternative protein source in broiler's diet. A total of 280-day-old unsexed broiler chicks were randomly distributed into four experimental groups in a simple randomised experimental design (each group had seven replicates; 10 birds per each). Four iso-nitrogenous and iso-caloric broiler starter and finisher diets (C, LCSL, MCSL and HCSL) were formulated containing 0%, 5%, 10% and 15% CSL respectively. Results revealed that chicks fed MCSL diet had significantly (p ≤ .05) the heaviest Body weight, highest Body weight gain and the lowest feed conversion ratio followed by those fed HCSL diet. In the starter period, LCSL and MCSL diets resulted in better (p ≤ .05) dry matter (DM) (89.57%) and crude protein (67.67%) digestibilities respectively. In the finisher period, DM, crude fibre and fat digestibilities were not affected by CSL inclusion levels; while crude protein digestibility was significantly (p ≤ .05) high in the groups fed LCSL and HCSL diets. The CSL inclusion had no effect on blood haematology except serum uric acid, which tended to increase with increasing CSL levels. No microscopic changes were exhibited on liver, heart, kidneys and intestine of birds across all dietary treatments. However, crops in birds fed HCSL diet showed moderate to severe hypertrophy and hyperplasia of the mucosal lining. The study showed that CSL could be added up to 15% in broiler's diet without any adverse effect on bird's performance.

Matrix type transdermal therapeutic systems of glibenclamide: Formulation, ex vivo and in vivo characterization

Matrix type transdermal therapeutic systems (TTS) of glibenclamide were formulated using polymers Eudragit RL 100, ethyl cellulose, PVP K-30, and polyvinyl acetate, and citral was used as the penetration enhancer. The polymer films were formulated with Eudragit RL 100 and PVP K-30 in different ratios and subsequently subjected to ex vivo studies (drug permeation through rat skin) followed by interaction studies, skin irritation studies, accelerated stability analysis, and in vivo studies (determination of blood glucose level in rabbits). The drug content of the formulations was found to be 99.1-99.2%. The cumulative percentages of drug permeated through rat skin from the three selected formulations in 48 h were 95.3%, 98.8%, and 99%, respectively. A plot between cumulative percent of drug permeated and square root of time exhibited linear curves, which suggests the Higuchian matrix mechanism of drug release. The formulation containing Eudragit RL 100 and PVP K-30 showed better improvement in hypoglycemic activity in rabbits (56.2-60.8% reduction in blood glucose level, p < 0.05). There were fewer fluctuations in blood glucose level as compared to oral therapy due to controlled release of the active pharmaceutical ingredient, and no interaction was found between the drug and excipients of the formulation. Accelerated stability analysis showed that the formulation was stable up to 5.5 years, with negligible skin irritation. The formulation precluded severe hypoglycemic reactions (side effect of sulfonylureas) and was effective for management of diabetes mellitus up to 48 h, with a single TTS.

Multidrug resistant neonatal sepsis in Peshawar, Pakistan

OBJECTIVE

To investigate the spectrum of organisms causing neonatal sepsis in Peshawar, Pakistan and to assess their sensitivity to various groups of drugs.

METHODS

Blood taken from newborn babies admitted to the special care baby unit at the Khyber Teaching Hospital with a clinical diagnosis of neonatal sepsis was cultured. The data obtained from October 1997 to December 2000 were analysed and the results tabulated.

RESULTS

A total of 1598 blood cultures were taken; 1003 were positive (positivity rate 62.8%). Escherichia coli was the most common organism found (36.6%), followed by Staphylococcus aureus (29.5%), Pseudomonas (22.4%), Klebsiella (7.6%), and Proteus (3.8%). No group B streptococcus was grown. Listeria monocytogenes was found in one cerebrospinal fluid culture. E coli and Pseudomonas showed a high degree of resistance to commonly used antibiotics (ampicillin, augmentin, and gentamicin), a moderate degree of resistance to cephalosporin (cefotaxime, ceftzidime, and ceftrioxone), and low resistance to drugs not used for newborn babies (ofloxacin, ciprofloxacin, and enoxabid). S aureus showed a low resistance to all three groups of antibiotics.

CONCLUSION

Neonatal sepsis remains one of the leading causes of neonatal admission, morbidity, and mortality in developing countries. Gram negative organisms are the major cause of neonatal sepsis in Peshawar. Such organisms have developed multidrug resistance, and management of patients infected with them is becoming a problem in developing countries.

Interaction between zucchini yellow mosaic potyvirus RNA-dependent RNA polymerase and host poly-(A) binding protein

Viral replication depends on compatible interactions between a virus and its host. For RNA viruses, the viral replicases (RNA-dependent RNA polymerases; RdRps) often associate with components of the host translational apparatus. To date, host factors interacting with potyvirus replicases have not been identified. The Potyviridae, which form the largest and most economically important plant virus family, have numerous similarities with the animal virus family, the Picornaviridae. Potyviruses have a single-stranded, plus sense genome; replication initiates at the viral-encoded, 3' poly-(A) terminus. The yeast two-hybrid system was used to identify host plant proteins associating with the RdRp of zucchini yellow mosaic potyvirus (ZYMV). Several cDNA clones representing a single copy of a poly-(A) binding protein (PABP) gene were isolated from a cucumber (Cucumis sativus L.) leaf cDNA library. Deletion analysis indicated that the C-terminus of the PABP is necessary and sufficient for interaction with the RdRp. Full-length cucumber PABP cDNA was obtained using 5' RACE; in vitro and Escherichia coli-expressed PABP bound to poly-(A)-Sepharose and ZYMY RdRp with or without the presence of poly-(A). This is the first report of an interaction between a viral replicase and PABP and may implicate a role for host PABP in the potyviral infection process.