Is EGD Needed in all Patients after Suicidal or Exploratory Caustic Ingestions?

BACKGROUND

Caustic ingestions are relatively uncommon, but remain a significant source of morbidity. Patients with caustic injury often undergo an urgent EGD, although it is not clear if an EGD is routinely needed in an asymptomatic patient. The study has two primary objectives; 1) to determine the utility of routine EGD in asymptomatic suicidal caustic ingestions; 2) to determine if asymptomatic unintentional acidic ingestions can be managed with observation alone, similar to basic ingestions.

METHODS

This retrospective study, which took place at 14 hospitals in three countries evaluated all patients who presented with a caustic ingestion between 2014-2020. The presence of symptoms and esophageal injury, demographic information, pH of ingested substance, reason for the ingestion, and outcome were recorded.

RESULTS

409 patients were identified; 203 (46.9%) were male. The median (IQR) age was 18 (4-31) years; overall range 10 months to 78 years. Suicidal ingestions accounted for 155 (37.9%) of cases. Dysphagia or dysphonia were more likely in those with significant esophageal injury compared to those without (59.3% vs. 12.6% respectively; OR 10.1; 95% CI 4.43-23.1). Among 27 patients with significant esophageal injury, 48% were found in suicidal patients, compared with 51.9% in non-suicidal patients (p = NS). On multivariate regression, there was no difference in the rate of significant esophageal injury among suicidal vs. non suicidal patients (aOR 1.55; p = 0.45, 95% CI 0.45-5.33). Most ingestions involved basic substances (332/409; 81.2%). Unknown or mixed ingestions accounted for 25 (6.11%) of the ingestions. Significant esophageal burns were found in 6/52 (11.5%) of acid ingestions, compared with 21/332 (6.3%) of basic ingestions. Of the 42 cases of acidic ingestions without dysphagia or odynophagia, 2 (4.8%; 0.58-16.1%) had significant esophageal burns, compared with 9 (3.2%; 95% CI 1.4-5.9%) of the 284 basic ingestions; p = 0.64). On multivariate logistic regression, patients with acidic ingestions were not more likely to experience a significant burn (aOR 1.7; p = 0.11, 95% CI 0.9-3.1) compared to those with basic ingestions. No patient with significant esophageal burns was asymptomatic.

CONCLUSION

In this study, there was no statistical differences in the rates of significant burns between acidic and basic caustic ingestions. There were no significant esophageal injuries noted among asymptomatic patients.

Novel functions of the anion exchanger AE4 (SLC4A9)

The kidney plays a crucial role in acid-base homeostasis. In the distal nephron, α-intercalated cells contribute to urinary acid (H+) secretion and β-intercalated cells accomplish urinary base (HCO3-) secretion. β-intercalated cells regulate the acid base status through modulation of the apical Cl-/HCO3- exchanger pendrin (SLC26A4) activity. In this review, we summarize and discuss our current knowledge of the physiological role of the renal transporter AE4 (SLC4A9). The AE4, as cation-dependent Cl-/HCO3- exchanger, is exclusively expressed in the basolateral membrane of β-intercalated cells and is essential for the sensing of metabolic acid-base disturbances in mice, but not for renal sodium reabsorption and plasma volume control. Potential intracellular signaling pathways are discussed that might link basolateral acid-base sensing through the AE4 to apical pendrin activity.

Iridium(III) solvent complex-based electrogenerated chemiluminescence and photoluminescence sensor array for the discrimination of bases in oligonucleotides

Development of rapid and sensitive method for the discrimination of bases in oligonucleotides is of great importance in clinical diagnosis. Here, we demonstrate the first case of single iridium(III) solvent complex-based electrogenerated chemiluminescence (ECL) and photoluminescence (PL) sensor array for the discrimination of bases in oligonucleotides. One iridium (III) solvent complex ([Ir(ppy)₂(DMSO)Cl], ppy = 2-phenylpyridine, probe 1) was designed as both ECL and PL probe while five bases (guanine, adenine, cytosine, thymine and uracil) were chosen as analytes. Two-element sensor array was built for the discrimination of five bases based on the fingerprint response of probe 1 to bases via coordination interactions. The combination of unique ECL and PL variations with principal component analysis was applied for the quantitative analysis of five bases in a linear range of 1.0 μM-10 μM and for the effective discrimination of individual base, the mixture of bases and oligonucleotides. Moreover, the sensor array was successfully applied to discriminate different mismatched ss-DNAs from HIV gene (a fully-matched ss-DNA), even at single-base difference. This work demonstrates that the sensor array using single iridium (III) solvent complex is a promising approach for the discrimination of bases with good sensitivity and simpleness in clinical diagnosis.

Base type determines the effects of nucleoside monophosphates on microalgae-bacteria symbiotic systems

Microalgae are promising sources of clean energy. Bioflocculation by cocultured bacteria is an effective way to harvest microalgae. As a key foundation for microorganisms, phosphorus is theoretically effective in shaping microalgae production and flocculation. In this study, the impacts of 23 nucleoside monophosphates on Auxenochlorella pyrenoidosa growth, lipid synthesis, and self-settlement and on the symbiotic bacterial system were investigated. Adenosine monophosphate was the most effective in enhancing microalgae development (2.14-3.16 × 10⁸ cells/mL) and lipid production (average 10.48%) and resulted in a low settling velocity. Samples were divided into two groups, purine and pyrimidine feeding, according to a random forest analysis (OOB = 0%, p < 0.001). Purine feeding resulted in the highest soluble extracellular protein and polysaccharide secretion (p < 0.01). KEGG ortholog count prediction of functional genes related to biofilm formation was conducted using PICRUSt2, and significant upregulation (FC ≥ 1.77, p < 0.05) of the extracellular polymeric substance formation functional group was observed in the adenosine and guanosine treatments. The symbiotic bacterial community structure differed substantially between purine- and pyrimidine-feeding systems. In summary, these results indicated that the effect of nucleoside monophosphates on the microalgae-bacteria system is determined by the base type (purine or pyrimidine) rather than the molecular structure (cyclic or noncyclic).

An in silico derived dosage and administration guide for effective thermochemical ablation of biological tissues with simultaneous injection of acid and base

BACKGROUND AND OBJECTIVES

Thermochemical ablation (TCA) is a thermal ablation technique involving the injection of acid and base, either sequentially or simultaneously, into the target tissue. TCA remains at the conceptual stage with existing studies unable to provide recommendations on the optimum injection rate, and reagent concentration and volume. Limitations in current experimental methodology have prevented proper elucidation of the thermochemical processes inside the tissue during TCA. Nevertheless, the computational TCA framework developed recently by Mak et al. [Mak et al., Computers in Biology and Medicine, 2022, 145:105494] has opened new avenues in the development of TCA. Specifically, a recommended safe dosage is imperative in driving TCA research beyond the conceptual stage.

METHODS

The aforesaid computational TCA framework for sequential injection was applied and adapted to simulate TCA with simultaneous injection of acid and base at equimolar and equivolume. The developed framework, which describes the flow of acid and base, their neutralisation, the rise in tissue temperature and the formation of thermal damage, was solved numerically using the finite element method. The framework will be used to investigate the effects of injection rate, reagent concentration, volume and type (weak/strong acid-base combination) on temperature rise and thermal coagulation formation.

RESULTS

A higher injection rate resulted in higher temperature rise and larger thermal coagulation. Reagent concentration of 7500 mol/m³ was found to be optimum in producing considerable thermal coagulation without the risk of tissue overheating. Thermal coagulation volume was found to be consistently larger than the total volume of acid and base injected into the tissue, which is beneficial as it reduces the risk of chemical burn injury. Three multivariate second-order polynomials that express the targeted coagulation volume as functions of injection rate and reagent volume, for the weak-weak, weak-strong and strong-strong acid-base combinations were also derived based on the simulated data.

CONCLUSIONS

A guideline for a safe and effective implementation of TCA with simultaneous injection of acid and base was recommended based on the numerical results of the computational model developed. The guideline correlates the coagulation volume with the reagent volume and injection rate, and may be used by clinicians in determining the safe dosage of reagents and optimum injection rate to achieve a desired thermal coagulation volume during TCA.

Mechanistic Understanding of KOtBu-Mediated Direct Amidation of Esters with Anilines: An Experimental Study and Computational Approach

A sustainable and cost-effective protocol has been reported for the synthesis of amide bonds from unactivated esters and non-nucleophilic amines promoted by potassium tert -butoxide under aerobic conditions. The reaction proceeds under relatively mild conditions, encompassing wide substrate scope. A combined experimental and quantum chemical study has been performed to shed light on the mechanism, which implied that a radical pathway is operating for the present protocol.

Promoted liquid-phase hydrodechlorination of chlorophenol over Raney Ni via controlling base: Performance, mechanism, and application

The potential effect of base on Raney Ni-catalyzed hydrodechlorination (HDC) of chlorophenol was studied. Compared to weak inorganic bases, strong inorganic bases (NaOH and KOH) and triethylamine (Et₃N) were more favorable to promote Raney Ni-catalyzed HDC reaction. Moreover, a stoichiometric amount of NaOH/Et₃N was found to be optimal for the HDC reaction, and up to 100% conversion of 4-chlorophenol was achieved within 30 min. Catalyst characterization (SEM, EDXS, and XRD) combined with ICP-OES analysis were introduced to better understand the mechanism for the promoted effect of base on the HDC reaction. The results showed that the optimal amount of strong inorganic bases and Et₃N efficiently eliminated HCl corrosion to Raney Ni, greatly reduced the active phase Ni and Al leaching, and avoided collapse of the catalyst framework. Based on the mechanism, the best bases and their optimal amount were developed for further disposal of polychlorinated phenols, and excellently stepwise HDC of polychlorinated phenols was achieved. Recycling tests showed that Raney Ni could be reused at least 5 times for the HDC reaction with the stoichiometric amount of NaOH, which was a promising option for the HDC of wastewater containing chlorophenols over Raney Ni.

Recommendations for Improving Methods and Models for Aquatic Hazard Assessment of Ionizable Organic Chemicals

Ionizable organic chemicals (IOCs) such as organic acids and bases are an important substance class requiring aquatic hazard evaluation. Although the aquatic toxicity of IOCs is highly dependent on the water pH, many toxicity studies in the literature cannot be interpreted because pH was not reported or not kept constant during the experiment, calling for an adaptation and improvement of testing guidelines. The modulating influence of pH on toxicity is mainly caused by pH-dependent uptake and bioaccumulation of IOCs, which can be described by ion-trapping and toxicokinetic models. The internal effect concentrations of IOCs were found to be independent of the external pH because of organisms' and cells' ability to maintain a stable internal pH milieu. If the external pH is close to the internal pH, existing quantitative structure-activity relationships (QSARs) for neutral organics can be adapted by substituting the octanol-water partition coefficient by the ionization-corrected liposome-water distribution ratio as the hydrophobicity descriptor, demonstrated by modification of the target lipid model. Charged, zwitterionic and neutral species of an IOC can all contribute to observed toxicity, either through concentration-additive mixture effects or by interaction of different species, as is the case for uncoupling of mitochondrial respiration. For specifically acting IOCs, we recommend a 2-step screening procedure with ion-trapping/QSAR models used to predict the baseline toxicity, followed by adjustment using the toxic ratio derived from in vitro systems. Receptor- or plasma-binding models also show promise for elucidating IOC toxicity. The present review is intended to help demystify the ecotoxicity of IOCs and provide recommendations for their hazard and risk assessment. Environ Toxicol Chem 2020;39:269-286. © 2019 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.

Integrating Acid-Base and Metabolic Lab Panels Across Systems in an M1 Classroom Activity

INTRODUCTION

It is important to deliver acid-base balance concepts in the context of multiple physiological systems and metabolic processes that influence acid-base homeostasis. This activity combines the interactions of the respiratory, gastrointestinal, and renal systems in conjunction with basic metabolism to generate an integrated activity for first-year medical students.

METHODS

We developed four concise case scenarios around various presentations of acid-base disturbance along with five sets of arterial blood gases (ABGs) and five different metabolic lab panels. M1 students were given class time to match the three different types of data in order to address how the underlying biochemistry and physiology of a scenario translated into ABG and metabolic laboratory values.

RESULTS

Although not statistically significant, the students' performance on acid-base questions was marginally higher than on standardized National Board of Medical Examiners questions on other topics covered in the same exam, and the improvement over national average scores on the same questions increased. Student evaluation of the activity was positive, with general appreciation of its application and integration of concepts.

DISCUSSION

The incorporation of this activity into the M1 year was positively received and enhanced integration of content related to acid-base balance. The activity is flexible and can be adapted to most any curricular structure, with the potential to include additional content depending on the level of the learner.

[Components of human placental extract and its protective effect to rat from D-GalN induced acute liver injury]

Objective: To evaluate the effect of human placental extracts (HPE) on the protection from acute liver injury (ALI) induced by D-GalN and analyze the components of HPE. Methods: (1)Fourty male mice were randomly divided into five groups (Blank, Model, MgIG, HPE and HPE+ MgIG) for the ALI model and treatments.The serum alanine aminotransferase (ALT) and aspartate transaminase (AST) were determined by biochemical assays.Nitric monoxide (NO), malondialdehyde (MDA), superoxide dismutase (SOD), total antioxidant capacity (T-AOC) in serum and hepatic tissue were detected by assay kits.The extent of liver damage was evaluated by histological examination.(2)Relative molecular mass of HPE was determined by SDS-PAGE.(3) Component identification was performed by using LCMS-TOF.(4)Selected functional molecules in HPE were detected by protein array. Results: (1) A lower level of NO and MDA and a higher SOD and T-AOC were observed in rats treated with HPE compared to the non-treated rats in an acute liver failure disease model.(2) The size of HPE was about 1 200-4 600 by electrophores.(3) 7 peaks of HPE were identified, including uracil, hypoxanthine, tyrosine, phenylalanine, tryptophan, xanthine and thymine.(4) Comparable high concentrations of TGF-β, IGF-1, IL-9, IL-29 and TNF-α of HPE were revealed by protein array. Conclusions: (1) HPE protects rat from liver damage induced by D-GalN. (2) HPE contains Uracil, hypoxanthine, xanthine, thymine, and functional proteins as TGF-β, IGF-1, IL-9, IL-29 and TNF-α.

A high-performance protocol for extraction of microplastics in fish

So far, several classes of digesting solutions have been employed to extract microplastics (MPs) from biological matrices. However, the performance of digesting solutions across different temperatures has never been systematically investigated. In the first phase of the present study, we measured the efficiency of different oxidative agents (NaClO or H₂O₂), bases (NaOH or KOH), and acids [HCl or HNO₃; concentrated and diluted (5%)] in digesting fish tissues at room temperature (RT, 25°C), 40, 50, or 60°C. In the second phase, the treatments that were efficient in digesting the biological materials (>95%) were evaluated for their compatibility with eight major plastic polymers (assessed through recovery rate, Raman spectroscopy analysis, and morphological changes). Among the tested solutions, NaClO, NaOH, and diluted acids did not result in a satisfactory digestion efficiency at any of the temperatures. The H₂O₂ treatment at 50°C efficiently digested the biological materials, although it decreased the recovery rate of nylon-6 (NY6) and nylon-66 (NY66) and altered the colour of polyethylene terephthalate (PET) fragments. Similarly, concentrated HCl and HNO₃ treatments at RT fully digested the fish tissues, but also fully dissolved NY6 and NY66, and reduced the recovery rate of most or all of the polymers, respectively. Potassium hydroxide solution fully eliminated the biological matrices at all temperatures. However, at 50 and 60°C, it degraded PET, reduced the recovery rate of PET and polyvinyl chloride (PVC), and changed the colour of NY66. According to our results, treating biological materials with a 10% KOH solution and incubating at 40°C was both time and cost-effective, efficient in digesting biological materials, and had no impact on the integrity of the plastic polymers. Furthermore, coupling this treatment with NaI extraction created a promising protocol to isolate MPs from whole fish samples.

Symptomatic treatment or cast immobilisation for avulsion fractures of the base of the fifth metatarsal: a prospective, randomised, single-blinded non-inferiority controlled trial

AIMS

The purpose of this study was to compare symptomatic treatment of a fracture of the base of the fifth metatarsal with immobilisation in a cast. Our null hypothesis was that immobilisation gave better patient reported outcome measures (PROMs). The alternative hypothesis was that symptomatic treatment was not inferior.

PATIENTS AND METHODS

A total of 60 patients were randomised to receive four weeks of treatment, 36 in a double elasticated bandage (symptomatic treatment group) and 24 in a below-knee walking cast (immobilisation group). The primary outcome measure used was the validated Visual Analogue Scale Foot and Ankle (VAS-FA) Score. Data were analysed by a clinician, blinded to the form of treatment, at presentation and at four weeks, three months and six months after injury. Loss to follow-up was 43% at six months. Multiple imputations missing data analysis was performed.

RESULTS

At four weeks and six months, symptomatic treatment proved non-inferior in terms of primary outcome.

TAKE HOME MESSAGE

Immobilisation is no better than symptomatic treatment in the management of a fracture of the base of the fifth metatarsal when judged by PROMs. Significant loss to follow-up with this injury could be expected in longer term. Cite this article: Bone Joint J 2016;98-B:806-11.

Oral transmucosal delivery of naratriptan

Naratriptan (NAR) is currently used as the hydrochloride salt (NAR.HCl) for the treatment of migraine and is available in tablet dosage forms for oral administration. Buccal drug delivery offers a number of advantages compared with conventional oral delivery including rapid absorption, avoidance of first pass metabolism and improved patient compliance. We have previously prepared and characterised the base form of NAR and shown that it has more favourable properties for buccal delivery compared with NAR.HCl. This study describes the design and evaluation of a range of formulations for oral transmucosal delivery of NAR base. Permeation studies were conducted using excised porcine buccal tissue mounted in Franz cells. Of the neat solvents examined, Transcutol^® P (TC) showed the greatest enhancement effects and was the vehicle in which NAR was most soluble. The mechanisms by which TC might promote permeation were further probed using binary systems containing TC with either buffer or Miglyol 812^® (MG). Mass balance studies were also conducted for these systems. The permeation of TC as well as NAR was also monitored for TC:MG formulations. Overall, TC appears to promote enhanced membrane permeation of NAR because of its rapid uptake into the buccal tissue. Synergistic enhancement of buccal permeation was observed when TC was combined with MG and this is attributed to the increased thermodynamic activity of NAR in these formulations. Significantly enhanced permeation of NAR was achieved for TC:MG and this was also associated with less TC remaining on the tissue or in the tissue at the end of the experiment. To our knowledge this is the first report where both enhancer and active have been monitored in buccal permeation studies. The findings underline the importance of understanding the fate of vehicle components for rational formulation design of buccal delivery systems.

Activation of peroxymonosulfate by base: Implications for the degradation of organic pollutants

Increasing attention has been paid to environmentally friendly activation methods of peroxymonosulfate (PMS) in advanced oxidation processes (AOPs) for organic pollutant elimination. This work demonstrates that Base can be applied as a novel activator for PMS. The Base/PMS system, at ambient temperature, was able to degrade a variety of organic pollutants, including acid orange 7 (AO7), phenol and bisphenol A. In subsequent experiments with AO7, the decolorization rates for AO7 followed pseudo-first-order kinetics, with rate constant values ranging from 0.0006 to 0.1749 min(-1) depending on the operating parameters (initial PMS, Base, AO7 concentrations and reaction temperature). Furthermore, the mechanism for PMS activation by the Base was elucidated by radical scavenger (tert-butyl alcohol, methanol, sodium azide and p-benzoquinone) and electron spin resonance trapping studies. The results revealed that superoxide anion radical and singlet oxygen other than sulfate radical were the primary reactive oxygen species in the Base/PMS system. The findings of this study present a new pathway for PMS activation and provide useful information for the treatment of wastewater.

Cavity lining after excavating caries lesions: meta-analysis and trial sequential analysis of randomized clinical trials

OBJECTIVES

After removal of dentine caries lesions, cavity lining has been advocated. Non-clinical data support this approach, but clinical data are sparse and ambiguous. We aimed at evaluating the benefits and harms of cavity lining using meta-analysis and Trial Sequential Analysis.

DATA

We included randomized clinical trials comparing restorations without versus with cavity lining for treating primary caries lesions. Only trials reporting failure (defined as need to re-retreat) after ≥1 year follow-up were included. Trial selection, data extraction, and risk of bias assessment were conducted independently by two reviewers. We conducted random-effects intention-to-treat and per-protocol meta-analyses, and Trial Sequential Analysis to control for random errors.

SOURCES

Electronic databases (PubMed, Embase, CENTRAL) were systematically screened, and hand searches and cross-referencing performed.

STUDY SELECTION

From 128 studies, three randomized trials (89/130 patients or teeth), all treating primary teeth, were included. The trials had high risk of bias. All trials compared no lining versus calcium hydroxide lining after selective caries removal followed by adhesive restoration. Follow-up was 36 to 53 months. Restoring the cavity without lining did not significantly affect the risk of failure (intention-to-treat relative risk (RR) (95% confidence interval) 0.71 (0.49-1.04), per-protocol RR 0.52 (0.24-1.10). According to Trial Sequential Analysis, no firm evidence was reached. The quality of evidence was very low.

CONCLUSIONS

Strong recommendations for using cavity liners are unsubstantiated, but firm evidence for omitting lining is also unavailable. Our findings apply only to primary teeth and calcium hydroxide liner.

CLINICAL SIGNIFICANCE

Whilst lining is frequently performed in dental practice, very few randomized clinical trials investigated this issue. The three trials included in this review treated deciduous teeth and did not find lining with calcium hydroxide beneficial. Lining is not supported by sufficient clinical evidence.

Conversion of lipid from food waste to biodiesel

Depletion of fossil fuels and environmental problems are encouraging research on alternative fuels of renewable sources. Biodiesel is a promising alternative fuel to be used as a substitute to the petroleum based diesel fuels. However, the cost of biodiesel production is high and is attributed mainly to the feedstock used which leads to the investigation of low cost feedstocks that are economically feasible. In this paper, we report on the utilization of lipid obtained from food waste as a low-cost feedstock for biodiesel production. Lipid from food waste was transesterified with methanol using base and lipase as catalysts. The maximum biodiesel yield was 100% for the base (KOH) catalyzed transesterification at 1:10M ratio of lipid to methanol in 2h at 60°C. Novozyme-435 yielded a 90% FAME conversion at 40°C and 1:5 lipid to methanol molar ratio in 24h. Lipid obtained from fungal hydrolysis of food waste is found to be a suitable feedstock for biodiesel production.

Solvent-free preparation of novel 2-[phenyl (pyridine-2-ylamino) methyl] phenols as pseudo-betti processor for natural products

BACKGROUND

2-Aminopyridine and benzaldehydes mixture readily reacted with phenols at 80°C without any solvents to produce novel 2-[phenyl (pyridine-2-yl amino (methyl] phenol derivatives as pseudo-Betti products in good to high yields. These compounds are efficient processor for synthesis of the natural products.

OBJECTIVES

We decided to report the synthesis of a series of novel N-heteroaryl-arylmethyl phenols via a simple three-component, one-pot method, using aromatic aldehydes, heteroaryl amines, and phenols in the absence of any acid catalysts and under solvent-free conditions.

MATERIALS AND METHODS

All starting materials were purchased from Merck and Aldrich companies. The IR spectra were recorded on a Perkin-Elmer RXI infrared spectrometer.

RESULTS

The reaction is convenient, operationally simple, proceeds quickly, and does not need solvents or expensive starting materials. The structures of the products were characterized by their spectral (1H NMR and IR) data.

CONCLUSIONS

We have developed a new, simple, and efficient method for one-pot aminoalkylation of active phenol compounds with various imines prepared from 2-aminopyrimidine and benzaldehydes in good to high yields (40%-97%).

Statistical investigation of simulated intestinal fluid composition on the equilibrium solubility of biopharmaceutics classification system class II drugs

A drug's solubility and dissolution behaviour within the gastrointestinal tract is a key property for successful administration by the oral route and one of the key factors in the biopharmaceutics classification system. This property can be determined by investigating drug solubility in human intestinal fluid (HIF) but this is difficult to obtain and highly variable, which has led to the development of multiple simulated intestinal fluid (SIF) recipes. Using a statistical design of experiment (DoE) technique this paper has investigated the effects and interactions on equilibrium drug solubility of seven typical SIF components (sodium taurocholate, lecithin, sodium phosphate, sodium chloride, pH, pancreatin and sodium oleate) within concentration ranges relevant to human intestinal fluid values. A range of poorly soluble drugs with acidic (naproxen, indomethacin, phenytoin, and piroxicam), basic (aprepitant, carvedilol, zafirlukast, tadalafil) or neutral (fenofibrate, griseofulvin, felodipine and probucol) properties have been investigated. The equilibrium solubility results determined are comparable with literature studies of the drugs in either HIF or SIF indicating that the DoE is operating in the correct space. With the exception of pancreatin, all of the factors individually had a statistically significant influence on equilibrium solubility with variations in magnitude of effect between the acidic and basic or neutral compounds and drug specific interactions were evident. Interestingly for the neutral compounds pH was the factor with the second largest solubility effect. Around one third of all the possible factor combinations showed a significant influence on equilibrium solubility with variations in interaction significance and magnitude of effect between the acidic and basic or neutral compounds. The least number of significant media component interactions were noted for the acidic compounds with three and the greatest for the neutral compounds at seven, with again drug specific effects evident. This indicates that a drug's equilibrium solubility in SIF is influenced depending upon drug type by between eight to fourteen individual or combinations of media components with some of these drug specific. This illustrates the complex nature of these fluids and provides for individual drugs a visualisation of the possible solubility envelope within the gastrointestinal tract, which may be of importance for modelling in vivo behaviour. In addition the results indicate that the design of experiment approach can be employed to provide greater detail of drug solubility behaviour, possible drug specific interactions and influence of variations in gastrointestinal media components due to disease. The approach is also feasible and amenable to adaptation for high throughput screening of drug candidates.

Tension band wiring for treatment of extra articular fracture of the base of first metacarpal

Eleven patients with unstable extra-articular fractures of the base of the first metacarpal with angulations more than 30° uncorrected by closed reduction were treated by open reduction and tension band fixation. Ten men and one woman with a mean age of 36.18 years. Fall on a stretched hand was the cause in eight while a punch in two and trauma from a basket ball in one. The mean follow up period was 12.45 months. All fractures united within a mean of 4.36 weeks. Patients were evaluated by subjective and objective criteria: the mean of pain was 0.5, quick-DASH was 10.48 and Kapandji score was 9.8. While the mean of the grip strength was 94 % and the pinch strength was 99 % of the contra lateral hand. There were no complications except local irritation of the k-wires in two patients that had to be removed at 4 months. Tension band technique proved to be a valuable technique which is easy to apply and gives rigid fixation with early mobilization.

Outcomes of closed reduction and periarticular pinning of base and shaft fractures of the proximal phalanx

PURPOSE

To review the results of periarticular pinning of extra-articular fractures of the proximal phalanx base and shaft.

METHODS

A retrospective review was performed of the senior author's practice (C.S.M.) from 2006 to 2012. The inclusion criteria were patients older than 18 years of age who underwent periarticular pinning of base or shaft fractures of the proximal phalanx. Age, sex, fracture location, fracture pattern, and time to surgery were recorded. Outcome measures were range of motion, time to healing, and complication rate.

RESULTS

A total of 43 patients with 50 fractures were identified. There were 19 men and 24 women with 16 shaft and 34 base fractures. Five fractures were open. The little finger was involved in 62%, the ring finger in 30%, and the index and middle fingers in 4% each. Most fractures were transverse or oblique, and just over half had comminution and/or impaction. Average follow-up was 17 weeks, and average time to clinical union was 35 days. Nine patients (18%) were lost to follow-up. Twenty-six fingers had excellent results (63%), lacking less than 10° of total motion. Seven patients (17%) had good results, lacking less than 20° of motion; 7 patients had fair results (17%); and 1 patient had a poor result. Three patients (7%) developed stiffness requiring tenolysis. There were 2 pin-site infections, 1 of which resulted in a loss of reduction. Results for shaft and base fractures were not significantly different.

CONCLUSIONS

Percutaneous periarticular pinning is an acceptable option for unstable base and shaft fractures of the proximal phalanx. Most fractures healed within 4 weeks. The majority of patients had excellent or good results.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

First metatarsal base osteotomies for hallux abducto valgus deformities

Proximal first metatarsal osteotomies have historically been associated with and limited to treatment of severe hallux valgus deformities. These procedures are powerful in deformity correction and overall realignment of first ray function because of their ability to correct closer to the deformity's origin. When considering all factors in bunion correction, they are good options for correction of a wide range of hallux abducto valgus deformities. This article discusses the use of proximal metatarsal osteotomies for correction of hallux valgus deformity, techniques to facilitate optimal outcome, and common complications of these osteotomies.

The Acid/Base Profile of the Human Metabolome and Natural Products

Human small molecule metabolites (the human metabolome) are a set of compounds that interact with at least one macromolecule in the biosphere. This study investigates the acid/base profile of the human metabolome, natural products and drugs, together with an analysis of their physicochemical properties. Ionisation constants (pKa values) are estimated for each compound and the identity of the ionisable functional groups in each set is determined. The acid/base and physicochemical property profile of the lipid component of the metabolome differed considerably to the other datasets. In contrast, the acid/base properties of non-lipid metabolites were found to be similar to both drugs and natural products. While the non-lipid metabolites have lower average ClogP values and more hydrogen bond donors than the other datasets, the distribution of physicochemical property values overlapped considerably with the drug dataset. Considering also that the non-lipid metabolites are of biochemical interest, their characteristics have great potential to influence the selection of screening compounds for drug discovery.