The bii4africa dataset of faunal and floral population intactness estimates across Africa's major land uses

Sub-Saharan Africa is under-represented in global biodiversity datasets, particularly regarding the impact of land use on species' population abundances. Drawing on recent advances in expert elicitation to ensure data consistency, 200 experts were convened using a modified-Delphi process to estimate 'intactness scores': the remaining proportion of an 'intact' reference population of a species group in a particular land use, on a scale from 0 (no remaining individuals) to 1 (same abundance as the reference) and, in rare cases, to 2 (populations that thrive in human-modified landscapes). The resulting bii4africa dataset contains intactness scores representing terrestrial vertebrates (tetrapods: ±5,400 amphibians, reptiles, birds, mammals) and vascular plants (±45,000 forbs, graminoids, trees, shrubs) in sub-Saharan Africa across the region's major land uses (urban, cropland, rangeland, plantation, protected, etc.) and intensities (e.g., large-scale vs smallholder cropland). This dataset was co-produced as part of the Biodiversity Intactness Index for Africa Project. Additional uses include assessing ecosystem condition; rectifying geographic/taxonomic biases in global biodiversity indicators and maps; and informing the Red List of Ecosystems.

Steroids from Diplazium esculentum: Antiplasmodial activity and molecular docking studies to investigate their binding modes

Diplazium esculentum is an edible fern commonly consumed by the local community in Malaysia either as food or medicine. Isolation work on the ethyl acetate extract of the stem of D. esculentum resulted in the purification of two steroids, subsequently identified as stigmasterol (compound 1) and ergosterol5,8-endoperoxide (compound 2). Upon further testing, compound 2 displayed strong inhibitory activity against the Plasmodium falciparum 3D7 (chloroquine-sensitive) strain, with an IC₅₀ of 4.27±1.15 µM, while compound 1 was inactive. In silico data revealed that compound 2 showed good binding affinity to P. falciparum-Sarco endoplasmic reticulum calcium-dependent ATPase (PfATP6); however, compound 1 did not show an antiplasmodial effect due to the lack of a peroxide moiety in the chemical structure. Our data suggested that the antiplasmodial activity of compound 2 from D. esculentum might be due to the inhibition of PfATP6, which resulted in both in vitro and in silico inhibitory properties.

237 POTENTIALLY INAPPROPRIATE PRESCRIBING IN HOSPITALISED FRAIL OLDER ADULTS: DEVELOPMENT OF THE OPTI-3S PRELIMINARY STATEMENTS

Background

Few assessment criteria exist for Potentially Inappropriate Medications (PIMs) in the hospital setting. This study aims to develop the preliminary statements of OPTI-3S, criteria for optimising medicines by stopping, stepping down or switching to safer alternatives. These are designed to be of value to clinical practitioners in the routine care of hospitalised, frail older adults.

Methods

A systematic literature review was conducted in the Cochrane Database of Systematic Reviews, the Cochrane Central Register of Controlled Trials, PubMed, CINAHL, EMBASE and Scopus (2010-2021). Search terms included the concepts of inappropriate prescribing, deprescribing and the target population (e.g. older, frail, hospitalized). This was supplemented with a PubMed focused search (2010-2021) using key words pertaining to the index diseases/conditions or inappropriate medications. The structured reviews included clinical based guidelines, PIMs lists, systematic/non-systematic reviews, or clinical/observational trials that assessed safe and/or effective use of medications in older adults. The preliminary statements were then drafted based on the available relevant evidence.

Results

Searches yielded ~1500 articles. These were included in structured reviews, yielding a total of 109 initial statements across seven physiological systems, and one patient-centred point of care (perioperative care). In addition to detailed PIMs statements (n=98), 11 statements address clinically important Potential Prescribing Omissions (PPOs) (e.g. anticoagulant underdosing) and altered blood pressure and glycaemic targets. Uniquely for criteria of this kind, 23 statements suggest PIMs be considered based on the different frailty levels, according to the Clinical Frailty Scale. 11/98 PIMs statements concern prescribing cascades and suggest tapering regimens for six inappropriate medication classes (e.g. antipsychotics, benzodiazepines). Several statements address medication appropriateness in other frailty related circumstances (e.g. non-compliance, overlapping co-morbidities, feeding tube incompatibility, pill burden/ polypharmacy).

Conclusion

Literature provides a large body of evidence to support prescribing optimization. This has been distilled into consensus-based statements, which should guide hospital-based health care professionals caring for frail older adults.

Evaluating expert-based habitat suitability information of terrestrial mammals with GPS-tracking data

AIM

Macroecological studies that require habitat suitability data for many species often derive this information from expert opinion. However, expert-based information is inherently subjective and thus prone to errors. The increasing availability of GPS tracking data offers opportunities to evaluate and supplement expert-based information with detailed empirical evidence. Here, we compared expert-based habitat suitability information from the International Union for Conservation of Nature (IUCN) with habitat suitability information derived from GPS-tracking data of 1,498 individuals from 49 mammal species.

LOCATION

Worldwide.

TIME PERIOD

1998-2021.

MAJOR TAXA STUDIED

Forty-nine terrestrial mammal species.

METHODS

Using GPS data, we estimated two measures of habitat suitability for each individual animal: proportional habitat use (proportion of GPS locations within a habitat type), and selection ratio (habitat use relative to its availability). For each individual we then evaluated whether the GPS-based habitat suitability measures were in agreement with the IUCN data. To that end, we calculated the probability that the ranking of empirical habitat suitability measures was in agreement with IUCN's classification into suitable, marginal and unsuitable habitat types.

RESULTS

IUCN habitat suitability data were in accordance with the GPS data (> 95% probability of agreement) for 33 out of 49 species based on proportional habitat use estimates and for 25 out of 49 species based on selection ratios. In addition, 37 and 34 species had a > 50% probability of agreement based on proportional habitat use and selection ratios, respectively.

MAIN CONCLUSIONS

We show how GPS-tracking data can be used to evaluate IUCN habitat suitability data. Our findings indicate that for the majority of species included in this study, it is appropriate to use IUCN habitat suitability data in macroecological studies. Furthermore, we show that GPS-tracking data can be used to identify and prioritize species and habitat types for re-evaluation of IUCN habitat suitability data.

Understanding and avoiding misplaced efforts in conservation

Conservation relies on cooperation among different interest groups and appropriate use of evidence to make decisions that benefit people and biodiversity. However, misplaced conservation occurs when cooperation and evidence are impeded by polarization and misinformation. This impedance influences actions that directly harm biodiversity, alienate partners and disrupt partnerships, waste resources, misinform the public, and (or) delegitimize evidence. As a result of these actions, misplaced conservation outcomes emerge, making it more difficult to have positive outcomes for biodiversity. Here we describe cases where a failed appreciation for cooperation, evidence, or both have eroded efforts to conserve biodiversity. Generally, these case studies illustrate that averting misplaced conservation requires greater adherence to processes that elevate the role of evidence in decision-making and that place collective, long-term benefits for biodiversity over the short-term gains of individuals or groups. Efforts to integrate human dimensions, cooperation, and evidence into conservation will increase the efficacy and success of efforts to conserve global biodiversity while benefiting humanity.

GSK3β: A plausible molecular target in the cytokinemodulating effect of exogenous insulin in a murine model of malarial infection

Malaria is a life-threatening disease caused by the Plasmodium sp. parasite. Infection results in heightened pro-inflammatory response which contributes to the pathophysiology of the disease. To mitigate the overwhelming cytokine response, host-directed therapy is a plausible approach. Glycogen synthase kinase-3β (GSK3β), a serine/threonine kinase plays a pivotal role in the regulation of inflammatory response during pathogenic infections. The present study was conducted to investigate the chemo-suppressive and cytokine-modulating effects of insulin administration in malaria-infected mice and the involvement of GSK3β. Intraperitoneal administrations of 0.3 and 0.5 U/kg body weight insulin each for four consecutive days into Plasmodium berghei NK65 (PbN)-infected mice resulted in chemo-suppression exceeding 60% and improved median survival time of infected mice (20.5 days and 19 days respectively compared to 15.5 days for non-treated control). Western analysis revealed that pGSK3β (Ser9) intensity in brain samples from insulin-treated (0.3 and 0.5 U/kg body weight) infected mice each were 0.6 and 2.2 times respectively than that in control. In liver samples, pGSK3β (Ser9) intensity from insulin-treated infected mice were significantly higher (4.8 and 16.1 fold for 0.3 and 0.5 U/kg bw respectively) than that in control. Insulin administration decreased both brain and liver pNF-κB p65 (Ser536) intensities (to 0.8 and 0.6 times for 0.3 U/kg bw insulin; and to 0.2 and 0.1 times for 0.5 U/kg bw insulin respectively compared to control). Insulin treatment (0.5 U/kg bw) also significantly decreased the serum levels of pro-inflammatory cytokines (TNF-α (3.3 times) and IFN-γ (4.9 times)) whilst significantly increasing the levels of anti-inflammatory cytokines (IL-4 (4.9 fold) and IL-10 (2.1 fold)) in PbN-infected mice. Results from this study demonstrated that the cytokinemodulating effects of insulin at least in part involve inhibition of GSK3β and consequent inhibition of the activation of NF-κB p65 suggesting insulin as a potential adjunctive therapeutic for malaria.

Genetic diversity in natural range remnants of the critically endangered hirola antelope

The hirola antelope (Beatragus hunteri) is considered to be the most endangered antelope in the world. In the ex situ translocated population at Tsavo East National Park, calf mortality and the critically low population numbers might suggest low genetic diversity and inbreeding depression. Consequently, a genetic study of the wild population is pivotal to gain an understanding of diversity and differentiation within its range before designing future translocation plans to increase the genetic diversity of the ex situ population. For that purpose, we assessed 55 individuals collected across five localities in eastern Kenya, covering its entire natural range. We used the complete mitochondrial DNA control region and microsatellite genotyping to estimate genetic diversity and differentiation across its range. Nuclear genetic diversity was moderate in comparison to other endangered African antelopes, with no signals of inbreeding. However, the mitochondrial data showed low nucleotide diversity, few haplotypes and low haplotypic differentiation. Overall, the inferred low degree of genetic differentiation and population structure suggests a single population of hirola across the natural range. An overall stable population size was inferred over the recent history of the species, although signals of a recent genetic bottleneck were found. Our results show hope for ongoing conservation management programmes and that there is a future for the hirola in Kenya.

Effects of body size on estimation of mammalian area requirements

Accurately quantifying species' area requirements is a prerequisite for effective area-based conservation. This typically involves collecting tracking data on species of interest and then conducting home-range analyses. Problematically, autocorrelation in tracking data can result in space needs being severely underestimated. Based on the previous work, we hypothesized the magnitude of underestimation varies with body mass, a relationship that could have serious conservation implications. To evaluate this hypothesis for terrestrial mammals, we estimated home-range areas with global positioning system (GPS) locations from 757 individuals across 61 globally distributed mammalian species with body masses ranging from 0.4 to 4000 kg. We then applied block cross-validation to quantify bias in empirical home-range estimates. Area requirements of mammals <10 kg were underestimated by a mean approximately15%, and species weighing approximately100 kg were underestimated by approximately50% on average. Thus, we found area estimation was subject to autocorrelation-induced bias that was worse for large species. Combined with the fact that extinction risk increases as body mass increases, the allometric scaling of bias we observed suggests the most threatened species are also likely to be those with the least accurate home-range estimates. As a correction, we tested whether data thinning or autocorrelation-informed home-range estimation minimized the scaling effect of autocorrelation on area estimates. Data thinning required an approximately93% data loss to achieve statistical independence with 95% confidence and was, therefore, not a viable solution. In contrast, autocorrelation-informed home-range estimation resulted in consistently accurate estimates irrespective of mass. When relating body mass to home range size, we detected that correcting for autocorrelation resulted in a scaling exponent significantly >1, meaning the scaling of the relationship changed substantially at the upper end of the mass spectrum.

Oral cholera vaccination coverage in an acute emergency setting in Somalia, 2017

The first oral cholera vaccination (OCV) campaign in Somalia was implemented between March and October 2017. It was the first time the Ministry of Health had introduced and used OCV as part of the cholera prevention and control strategies. The Ministry of Health aimed to cover 1.1 million people ≥ 1 year with 2 doses of the OCV in 11 high-risk districts. Overall, 2-dose administrative OCV coverage in all targeted districts was 95.5%. Following the campaign, a random sample survey was conducted in 9 out of 11districts to evaluate coverage, awareness, reasons for non-vaccination, the water and sanitation status of households, and any resulting adverse events. The survey was conducted in 2 phases. Of the 3,715 eligible individuals in the first phase, 92.5% (95% CI 91.4-93.6%) received 2 doses of the OCV and 7.0% (95% CI 6.0-8.2%) 1 dose. In the second phase, of 1,926 individuals, 94.1% (95% CI 92.9-95.1%) received 2 doses and 2.6% (95% CI 2.0-3.4%) 1 dose. Despite challenges, this experience shows that OCV campaigns can be implemented in acute humanitarian settings through existing immunization structures.

P1481 Embolic infarct in a known coronary artery disease patient

A 60 y/o diabetic and hypertensive lady with previous anterior infarction treated by primary PCI with stenting of the proximal LAD (2011) and CABG for stent thrombosis, presented for chest pain. Admission ECG showed ST segment elevation in II, III aVF, ST segment depression in V1-V2 (A). Urgent coronary angiography was performed. It showed non-significant lesions on RCA and LCX, occlusion of the proximal LAD stent, patent LIMA to LAD and first diagonal with non-significant stenosis of the distal anastomosis (B). Transthoracic echocardiography (C) showed calcific mass involving the mitral annulus and posterior mitral leaflet, moderate mitral regurgitation, hipokinesia of the basal segment of the inferior wall with preserved LV ejection fraction. Transesophageal echocardiography (D) confirmed the calcified mass involving the mitral annulus and the posterior mitral leaflet. There was no significant mitral stenosis, and mitral regurgitation was moderate. Thoracic CT showed massive mitral calcification and a possible thrombus attached to it. (E)

Myocardial infarction was confirmed by troponin rise and fall. The patient was discharged on dual antiplatelet therapy, ACE-I, betablocker and statin. At one month follow-up transthoracic echocardiography the central area of the mitral mass became hypoechogenic, and a bilobated hypermobile structure was seen attached to the ventricular side of the mass (F). Blood cultures were negative and there was no inflammatory syndrome. Cardiac magnetic resonance (H) confirmed myocardial infarction and showed massive calcification of the posterior mitral annulus. TEE performed after another month showed a very long hypermobile structure attached to the mitral annulus calcification, which was entering the left ventricular outflow tract reaching the plane of the aortic valve (G). The patient underwent surgical mitral valve replacement and redo CABG and the mass was excised. The pathologic aspect of the excised material was cazeous and friable (I).

The initial presentation was presumably an embolic infarct with cazeous material.

Abstract P1481 Figure.

Anti-malarial and cytokine-modulating effects of andrographolide in a murine model of malarial infection

Malarial pathogenesis involves among others, uncontrolled or excessive cytokine production arising from dysregulated immune responses mounted by the host to eliminate the plasmodial parasite. The ubiquitous serine/threonine kinase, glycogen synthase kinase3β (GSK3β) is a crucial regulator of the balance between pro- and anti-inflammatory cytokine productions in the inflammatory response to pathogenic infections. Andrographolide, a bioactive compound in Andrographis paniculata, displays GSK3- inhibitory effects. A previous study elsewhere has shown that this compound has antimalarial activity but the molecular basis of its action is yet to be elucidated. Here we aimed to study the anti-malarial activity of andrographolide in a murine model of malarial infection to investigate whether its mechanism of action involves cytokine modulation and inhibition of GSK3β. Andrographolide showed strong and selective anti-plasmodial activity (IC₅₀ = 13.70±0.71 µM; SI = 30.43) when tested against cultures of P. falciparum 3D7. Intraperitoneal administration of andrographolide (5 mg/kg body weight (bw)) into P. berghei NK65-infected ICR mice resulted in chemo-suppression of 60.17±2.12%, and significantly (P<0.05) improved median survival time of infected mice compared to nontreated control. In addition, andrographolide treatment significantly (P<0.05) decreased the level of serum pro-inflammatory cytokine, IFN-γ (1.4-fold) whilst the anti-inflammatory cytokines, IL-10 and IL-4 were increased 2.3- and 2.6-fold respectively. Western blot analyses revealed that andrographolide treatment of P. berghei NK65-infected mice resulted in an increased level of phosphorylated GSK3β (Ser9) in liver of infected mice. Andrographolide administration also decreased the levels of phosphorylated NF-κB p65 (Ser536) and phosphorylated Akt (Ser473) in liver of malaria- infected animals. Taken together, our findings demonstrate that the cytokine-modulating effect of andrographolide in experimental malarial infection involves at least in part inhibition of NF-κB activation as a consequence of GSK3β inhibition. Based on its cytokine-modulating effects, andrographolide is thus a plausible candidate for adjunctive therapy in malaria subject to clinical evaluations.

Sudden sensorineural hearing loss: A missed opportunity for treatment

Sudden sensorineural hearing loss (SSNHL) is an otology emergency and carries significant morbidity if the diagnosis is missed. It can present to any specialty but in our local setting the patient usually presents to primary care as it is easily accessible. We present a case of SSNHL that was initially presented to a primary care centre and the patient was reassured without any investigation being carried out. SSNHL has many causes thus making diagnosis difficult. However, with knowledge of its possible, a diagnosis can be made and appropriate management can be advocated to the patient. Hence, we discuss the three main causes of SSNHL, while emphasizing the immune system-mediated mechanism as the main cause in this case.

Moving in the Anthropocene: Global reductions in terrestrial mammalian movements

Animal movement is fundamental for ecosystem functioning and species survival, yet the effects of the anthropogenic footprint on animal movements have not been estimated across species. Using a unique GPS-tracking database of 803 individuals across 57 species, we found that movements of mammals in areas with a comparatively high human footprint were on average one-half to one-third the extent of their movements in areas with a low human footprint. We attribute this reduction to behavioral changes of individual animals and to the exclusion of species with long-range movements from areas with higher human impact. Global loss of vagility alters a key ecological trait of animals that affects not only population persistence but also ecosystem processes such as predator-prey interactions, nutrient cycling, and disease transmission.

Review article: the evidence that vancomycin is a therapeutic option for primary sclerosing cholangitis

BACKGROUND AND AIMS

PSC is an autoimmune biliary inflammatory disorder that is often associated with inflammatory bowel disease (IBD), with 50%-75% of patients with PSC having coexisting IBD, most commonly ulcerative colitis. Currently, no medical therapies have been shown to improve the disease course or slow its progression. However, ongoing research has resulted in a growing interest in the use of antibiotics for treatment of PSC, of which vancomycin is the most studied. In this review, we summarise the current evidence on the use of vancomycin in PSC and comment on future research areas of interest.

METHODS

A comprehensive PUBMED and EMBASE literature search for articles on vancomycin, PSC, therapeutic options and microbiome was performed.

RESULTS

Two randomised clinical trials, three case series and two case reports were included in the study. These include uncontrolled data from at least 98 patients that include promising improvements in biochemistry and imaging. Optimal dosing regimens are unclear.

CONCLUSION

Vancomycin is one of the most studied antibiotics used in the treatment of PSC with promising results. There is not currently sufficient evidence to support treatment recommendations. Further research is needed to establish if vancomycin is a PSC treatment.

Demographic drivers of a refugee species: large-scale experiments guide strategies for reintroductions of hirola

Effective reintroduction strategies require accurate estimates of vital rates and the factors that influence them. The hirola (Beatragus hunteri) is the rarest antelope on Earth, with a global population size of <500 individuals restricted to the Kenya-Somali border. We estimated vital rates of hirola populations exposed to varying levels of predation and rangeland quality from 2012 to 2015, and then built population matrices to estimate the finite rate of population change (λ) and demographic sensitivities. Mean survival for all age classes and population growth was highest in the low-predation-high-rangeland-quality setting (λ = 1.08 ± 0.03 [mean ± SE]), and lowest in the high-predation-low-rangeland-quality setting (λ = 0.70 ± 0.22). Retrospective demographic analyses revealed that increased fecundity (the number of female calves born to adult females annually) and female calf survival were responsible for higher population growth where large carnivores were absent. In contrast, variation in adult female survival was the primary contributor to differences in population growth attributable to rangeland quality. Our analyses suggest that hirola demography is driven by a combination of top-down (predation) and bottom-up (rangeland quality) forces, with populations in the contemporary geographic range impacted both by declining rangeland quality and predation. To enhance the chances of successful reintroductions, conservationists can consider rangeland restoration to boost both the survival and fecundity of adult females within the hirola's historical range.

Changes in and shortcomings of drug stockpiling, vaccine development and related policies during outbreaks of avian influenza A H5N1, H1N1, and H7N9 among humans

The purpose of this paper is to provide a reference for the future stockpiling of drugs and developing vaccines for treatment of emerging infectious diseases by summarizing the status of drug stockpiling, vaccine development, and related policies during three major outbreaks of avian influenza among humans (H5N1 in 2003, H1N1 in 2009, and H7N9 in 2013). Documents regarding drug stockpiling and vaccine development during three influenza outbreaks have been reviewed. Results indicated that the response to pandemic influenza outbreaks has improved markedly in terms of stockpiles of antivirals and vaccine development. These improvements also suggest advances in related policy planning. These trends also foreshadow better prospects for prevention and control of emerging infectious diseases. However, the rationality of drug stockpiling and international cooperation still needs to be enhanced.

Access to genitourinary medicine clinics: how long does it take to book an appointment by telephone?

A unique feature of genitourinary (GU) medicine clinics is that patients can book appointments themselves. The aim of this study was to assess how long it takes and the barriers that exist when making an appointment in a UK GU medicine clinic. Male and female researchers recorded the number of attempts needed to make a successful contact, how the call was dealt with, and the time taken for the call to be initially answered and then completed; 72% (479/666) of the telephone contacts were answered on the first attempt (range: 1-17). The median length of the total call was one minute 51 seconds (range: 15 seconds to eight minutes, six seconds) but male callers took a mean of 40 seconds longer to complete a call (P < 0.001), reflecting additional and often intrusive questions they were asked compared with female researchers. Care should be taken to ensure that the first point of contact with a clinic is favourable as it reflects on how an entire service may be perceived.

New role of antinutritional factors, phytic acid and catechin in the treatment of CCl4 intoxication

Both phytic acid (PA) and catechin (CA) are well known antioxidants of natural origin. They were frequently tried on experimental level as hepatoprotectants, relying only on their antioxidant properties. The present study was conducted mainly to outline the other biochemical pathways underlying the hepatotherapeutic potential of both drugs and to check a possible synergistic action if prescribed concomitantly. As both materials are frequently taken on a daily basis in food and drinks, it will be helpful to pursue their possible utility and/or to check if their value is really of medical importance. For this purpose, CCl(4) was used as a hepatotoxin, we evaluated plasma total sialic acid (TSA), serum ascorbic acid (AA) levels, liver tissue thiobarbituric acid reactive species (TBARS) as a marker for lipid peroxidation and total protein (TP) content as a rough marker to measure hepatic synthetic capability in 80 male Wistar rats as experimental models. Animals were classified into 8 groups (10 rats each), the first as control, the second as PA treated (0.3 mg kg (-1)), orally, the third as CA treated (30 mg kg (-1)) intraperitoneally, the fourth given both drugs, as a single daily dose for 2 weeks. The same design was repeated 24 hours after CCl(4)-intoxication (1mL kg (-1)), intraperitoneally, as a single dose. The results revealed that both PA and CA when used individually, significantly down-regulated TSA in both physiologic (no CCl(4 )treatment) and pathologic (CCl(4)- intoxication) states accompanied by significant decrease in lipoperoxidation. The therapeutic action against TSA and the antioxidant power were abolished by co-administration of both drugs . AA was only decreased by PA and the combination in the physiologic state. Both PA and CA showed significant therapeutic effect for protein synthesis against CCl(4)-intoxication, but the combination abolished this effect. We conclude that both drugs can be considered as a chemotherapeutic against hepatopathies and we for the first time contraindicate the concomitant use of both drugs.

Diabetes-induced biochemical changes in rat lens: attenuation of cataractogenesis by pyruvate

AIM

Studies have been conducted to determine the effect of pyruvate administration on the biochemistry of rat lens and the status of its transparency as affected by diabetic conditions.

METHODS

Sprague-Dawley rats were rendered diabetic by intravenous (i.v.) injection of streptozotocin (55 mg/kg body weight (b.w.)) and treated with sodium pyruvate (2%) in drinking water. The levels of glucose, fructose, sorbitol, ATP, GSH, MDA as well as glycated proteins in the lenses were determined at various intervals after the onset of diabetes and the values compared with untreated diabetic controls. The progress of cataract formation and associated histological changes in the tissue were also monitored.

RESULTS

Studies show that the pyruvate treatment decreased the extent of several biochemical changes known to be associated with cataract formation, such as the elevation in the levels of glycated proteins, sorbitol, lipid peroxidation (MDA) and inhibition of the cation pump. The progress of cataract was also significantly delayed.

CONCLUSION

Exogenous administration of this compound hence was found to exert an overall protective effect against cataract formation induced by the diabetic conditions.

Attenuation of sugar cataract by ethyl pyruvate

Studies describe an attenuation of sugar cataract formation by topical administration of ethyl pyruvate. Cataract formation was induced by feeding young rats a 30% galactose diet. Mature cataracts appeared in about thirty days. Instillation of the eye drops containing 5% ethyl pyruvate decelerated the process significantly. Biochemically, the effect was reflected by lowering in the contents of dulcitol and glycated proteins. The ATP levels were also higher in comparison to the placebo treated group. The effects are hence attributable to the effect of pyruvate in inhibiting dulcitol synthesis and protein glycation, in addition to its antioxidant properties and metabolic support. The use of esterified pyruvate instead of the unesterified pyruvate was preferred because of its greater penetration through the cornea and consequently a higher concentration attained in the aqueous humor.

Upper gastrointestinal endoscopy findings at Riyadh Armed Forces Hospital

Full text is available as a scanned copy of the original print version.

Non-enzymatic glycation of lens proteins and haemoglobin-inhibition by pyruvate: an in-vivo study

AIM

Previous studies have demonstrated that pyruvate can prevent protein glycation and oxidative stress under in-vitro conditions. The aim of this study was to examine the in-vivo effectiveness of this metabolite against glycation of lens crystallins and haemoglobin in galactosemic rats.

METHODS

Sprague-Dawley rats were maintained on a 30% or 50% galactose-containing diet in the absence or presence of 2% or 5% pyruvate in food and water, respectively. The animals were killed subsequently and the extent of glycation of lens crystallins and haemoglobin was determined using an affinity column chromatograpic technique.

RESULTS

Maintenance of rats on the high galactose diet resulted in a significant increase in glycation of both the proteins. The increase was faster and more substantial in the animals maintained on the 50% galactose diet than that in the animals fed a 30% galactose diet. The increase in the latter was also very significant. Supplementation with pyruvate inhibited the process.

CONCLUSION

The inhibition is attributable to a competitive binding of pyruvate to the protein NH2 groups as well as to the antioxidant effect of the compound. The studies therefore suggest that this and other alpha-keto-acids may be physiologically useful in minimizing glycation and oxidative stress induced tissue pathology by the hyperglycaemic conditions, such as diabetes and galactosemia. The results are also considered pharmacologically significant.

Attenuation of galactose-induced cataract by pyruvate

Data in the present paper demonstrate a significant inhibition in the progress of sugar cataract formation by systemic administration of pyruvate. The formation of the cataract was induced by feeding young rats a diet containing 30% galactose. All animals fed this diet developed nuclear lens opacity by the end of 30 days. This was delayed if the diet and water contained, in addition, 2% sodium pyruvate. The incidence of cataract in the latter group was 0% at day 30 and only 25% at day 55. Physiologically, the inhibition was associated with the prevention of lens membrane damage as reflected by its ability to maintain transport of rubidium ions against a concentration gradient; decreased tissue hydration as indexed by the lens wet weight; inhibition of protein glycation, and higher levels of ATP. Since pyruvate, being a normal tissue metabolite, is likely to be non-toxic, the findings are considered useful for further pharmacological studies with this and other similar metabolites, relevant to protection against various secondary complications of diabetes and galactosemia.

Corneal damage by half mustard (2-chloroethyl ethyl sulfide, CEES) in vitro preventive studies: a histologic and electron microscopic evaluation

The effect of half-mustard (2-chloroethyl ethyl sulfide, CEES) on the morphology and ultrastructure of the cornea has been studied in vitro. Extensive necrotic changes were observed histologically as well as electron microscopically. The outer layer of corneal epithelium was observed to undergo vacuolization and globulization prior to its denudation. The epithelium becomes separated from the Bowman's membrane. These necrotic changes are prevented from taking place in the presence of a mixture of taurine, pyruvic acid, alpha-keto glutaric acid and pantothenic acid suggesting the use of this mixture in the prevention of mustard damage.

Half mustard (CEES) induced damage to rabbit cornea: attenuating effect of taurine-pyruvate-alpha-ketoglutarate-pantothenate mixture

Studies have been conducted on the corneal damage by half mustard (2-chloroethyl-ethyl sulfide, CEES) and its possible prevention by a mixture of taurine, alpha-ketoglutarate, pyruvate and pantothenate. CEES has been found to damage the membrane permeability function of the corneal epithelium as evidenced by increased flux of the rubidium ion from the epithelial to the endothelial side. The cornea also loses its transparency. These damaging effects are preventable by the above mixture labeled as VM. It is conceived that use of such a mixed formulation may provide a pharmacological means of prophylactic and post-exposure treatment against the tissue damage caused by exposure to the mustards.

Oxidative stress to rat lens in vitro: protection by taurine

The concentration of taurine is high in the lens. However, its function therein remains unknown. Studies from other tissues suggest that in addition to several other modes of action, it acts as an antioxidant. We therefore hypothesize that taurine may be a part of the antioxidant defense mechanisms involved in protecting the lens against oxidative stress and consequent cataract formation. In these studies, the protective effect of taurine was examined using lens culture system with menadione as an oxidant. Inclusion of this compound in the incubation medium was found to have several adverse effects on the lens, such as a decrease in its ability to accumulate rubidium against a concentration gradient and fall in the levels of glutathione, ATP and an increase in water insoluble proteins. All these deleterious effects were attenuated significantly by addition of physiological amounts of taurine to the menadione-containing medium.

Prevention of intracellular oxidative stress to lens by pyruvate and its ester

Pyruvate is a well-known scavenger of hydrogen peroxide (H2O2). In addition, it scavenges superoxide radical (O2.-). However, evidence on its intracellular antioxidant function is meager at present. Hence, we have examined the effectiveness of this metabolite and its ethyl ester against intracellular oxidative damage to the lens under organ culture. Menadione, a redoxcycling quinone, was used to generate the reactive oxygen species (ROS). It was found to inhibit lens metabolism as evidenced by a decrease of ATP. Additionally, tissue oxidation was apparent by loss of glutathione (GSH), and increase in the level of oxidized glutathione (GSSG), coupled with increase of the urea soluble proteins (water insoluble). The overall physiological damage was apparent by the inhibition of the Na+-K+-ATPase dependent cation pump, as evidenced by a decreased rubidium transport. These deleterious effects were attenuated by pyruvate and ethyl-pyruvate. The later was found to be more effective.

Prevention of lens protein glycation by taurine

Modifications in lens protein structure and function due to nonenzymic glycosylation and oxidation have been suggested to play a significant role in the pathogenesis of sugar and senile cataracts. The glycation reaction involves an initial Schiff base formation between the protein NH2 groups and the carbonyl group of a reducing sugar. The Schiff base then undergoes several structural modifications, via some oxidative reactions involving oxygen free radicals. Hence certain endogenous tissue components that may inhibit the formation of protein-sugar adduct formation may have a sparing effect against the cataractogenic effects of sugars and reactive oxygen. The eye lens is endowed with significant concentration of taurine, a sulfonated amino acid, and its precursor hypotaurine. It is hypothesized that taurine and hypotaurine may have this purported function of protecting the lens proteins against glycation and subsequent denaturation, in addition to their other functions. The results presented herein suggest that these compounds are indeed capable of protecting glycation competitively by forming Schiff bases with sugar carbonyls, and thereby preventing the glycation of lens proteins per se. In addition, they appear to prevent oxidative damage by scavenging hydroxyl radicals. This was apparent by their preventive effect against the formation of the thiobarbituric acid reactive material generated from deoxy-ribose, when the later was exposed to hydroxyl radicals generated by the action of xanthine oxidase on hypoxanthine in presence of iron.

Formation of advanced glycation end (AGE) products in diabetes: prevention by pyruvate and alpha-keto glutarate

Glycation of proteins and their subsequent structural and functional modifications have been ascribed to play a prominent role in the pathogenesis of several secondary complications of diabetes, such as cataract and retinopathy. In addition, it plays a role in the generalized ageing process as well. Investigations have been conducted to explore the possibility of preventing the above process by use of pyruvate and alpha-keto glutarate as representatives of physiologically compatible keto acids. The results demonstrate that both these compounds are effective in preventing the initial glycation reaction as well as the formation of AGE products. Both these compounds also inhibit the generation of high molecular weight aggregates associated with cataract formation. Mechanistically, the preventive effects appear to be due to (1) competitive inhibition of glycation by the keto acids and (2) the antioxidant (radical scavenging) properties of these compounds. The results are hence considered useful from the point of view of developing these and other keto acid derivatives as pharmacological agents useful in preventing glycation related protein changes and consequent tissue pathological manifestations.

Nitrite-induced photo-oxidation of thiol and its implications in smog toxicity to the eye: prevention by ascorbate

Studies have been conducted on nitrite-induced oxidation of corneal thiols and reduced glutathione (GSH). Oxidation of GSH in the presence of nitrite (NaNO2) was minimal in the dark. Exposure of GSH to UV (365 nm) in the presence of nitrite substantially accelerated this oxidation; only < 10% of the original GSH remained at the end of 20 minutes. A similar Thiol depletion was observed in the case of corneal epithelial extracts irradiated with UV in the presence of the nitrite. Nitrite is therefore considered to be a potent phototoxicant with possible pathophysiological implications to the external eye tissues. Ascorbate was found to be effective in preventing thiol oxidation, suggesting the possibility of preventing nitrogen oxide-based smog irritation to the eye by this physiologically compatible antioxidant.

Prevention of oxidative damage to rat lens by pyruvate in vitro: possible attenuation in vivo

Studies have been conducted to assess the possible preventive effect of pyruvate against lens protein oxidation and consequent denaturation and insolubilization. Rat lens organ culture system was used for these studies. The content of water insoluble proteins (urea soluble) increased if the lenses were cultured in medium containing hydrogen peroxide. Incorporation of pyruvate in the medium prevented such insolubilization. The insolubilization was associated primarily with loss of gamma crystallin fraction of the soluble proteins. PAGE analysis demonstrated that insolubilization is related to -S-S- bond formation which was preventable by pyruvate. Since pyruvate is a normal tissue metabolite the findings are considered pathophysiologically significant against cataract formation. This was apparent by the prevention of selenite cataract in vivo by intraperitoneal administration of pyruvate.

Binding of polychlorinated biphenyls to the aryl hydrocarbon receptor

A new thermodynamic model for calculating the dissociation constants of complexes formed between the aryl hydrocarbon receptor (AhR) and polychlorinated biphenyls (PCBs) is reported. The free energies of binding of PCBs to AhR are controlled by their lipophilicities, electron affinities, and entropies. The corresponding physicochemical properties of polychlorinated dibenzo-p-dioxins and dibenzofurans also control their interactions with AhR. We present evidence supporting the hypothesis that the majority of PCBs are likely to interact with AhR in their nonplanar conformations. In addition, we demonstrate that the affinities of PCBs for AhR relative to 2,3,7,8-tetrachlorodibenzo-p-dioxin correlate with corresponding toxic equivalency factors in animals. The reported methodology is likely to be applicable to other polyhalogenated and mixed polyhalogenated bi- and terphenyls and related xenobiotics; thus, it could minimize the number of in vivo studies in laboratory animals and facilitate the identification of potentially hazardous aromatic xenobiotics.

Affinities for the aryl hydrocarbon receptor, potencies as aryl hydrocarbon hydroxylase inducers and relative toxicities of polychlorinated biphenyls. A congener specific approach

Polychlorinated biphenyls (PCBs) are nonplanar aromatic xenobiotics that are not structurally related to polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs), yet, some PCBs are potent ligands for the aryl hydrocarbon receptor (AhR), active inducers of aryl hydrocarbon hydroxylase (AHH) and 7-ethoxyresorufin O-deethylase (EROD), and elicit toxicological responses in animals similar to PCDDs and PCDFs. We report new methodologies for quantifying the affinities of PCBs for AhR and corresponding potencies as AHH and EROD inducers. The models show that lipophilicities, electron affinities, entropies and electronic energy gaps of PCBs are key physicochemical properties controlling their AhR, AHH and EROD activities. Using 3,3',4,4'-tetrachlorobiphenyl (TCB) as the reference compound, it is shown that PCBs having higher electron affinities, lower lipophilicities and entropies than TCB are potent ligands for rat hepatic AhR. In addition, the congeners having higher binding affinities to AhR and smaller energy gaps than TCB are potent AHH and EROD inducers in rat hepatoma cells in culture. The reported models qualitatively explain and quantify AhR, AHH and EROD activities of all 209-PCBs and related xenobiotics, e.g. PCDDs and PCDFs. Furthermore, we demonstrated that AhR and AHH activities of PCBs relative to 2,3,7,8-tetrachlorodibenzo-p-dioxin correlate with corresponding in vivo relative toxicities in animals as well as assigned toxic equivalency factors. The reported methodologies are likely to be useful for identifying potentially toxic aromatic xenobiotics in mammals, and minimizing the need for animal testing.

Pulmonary arterio-venous fistula in a child: a rare cause of congenital cyanosis

A 12-year-old girl with a solitary pulmonary arterio-venous fistula (P.A.V.F.) affecting the R.L.L. is reported. The cyanosis was noted since birth and increased with age. The diagnosis was confirmed by right heart catheterization and pulmonary arteriography. Preoperatively, her hematocrit was 73%, paO2 36 mm Hg and no bruit was heard. The treatment consisted of a right lower lobectomy. One year postoperatively, the patient has normal activities, is asymptomatic and has no evidence of residual disease. A short review of the literature on the subject of P.A.V.F. is included and indicates the relative rarity of surgical treatment of this disease in childhood.

In situ hypothermic renal perfusion. Evaluation of three intracellular solutions

Description of a simple technique for in situ hypothermic renal perfusion is presented. Three intracellular solutions simulating perfusates were tried on three groups of mongrel dogs with a fourth group that served as control. Right nephrectomy was performed on all dogs. The left kidney was perfused for two and one-half hours at a temperature of 15 degrees to 17 degrees C. Follow-up evaluation by estimation of five enzymes, glutamic oxaloacetic transaminase, alkaline phosphatase, lactic dehydrogenase, sorbitol dehydrogenase, and phospholexose isomerase in serum, urine, and renal tissue was conducted. Renal function was evaluated by the level of serum creatinine and its twenty-four-hour urinary excretion. Minimal biochemical changes comparable to the control group were observed in the group perfused by Chapman solution.