Assessing and comparing chest radiograph interpretation in the Department of Internal Medicine at the University of the Witwatersrand medical school, according to seniority.

Background: Chest radiographs are a common diagnostic tool in the internal medicine department, and correct interpretation is imperative for adequate patient management. Objectives: To determine the diagnostic accuracy of common pathologies in South Africa that are evident on chest radiographs, and to determine whether there are discrepancies according to different levels of qualification of doctors rotating through the internal medicine department, and which factors contribute to an accurate diagnosis. Methods: Fifteen chest radiographs with common pathologies were given to all doctors rotating through the Department of Internal Medicine at Chris Hani Baragwanath Academic Hospital, and they were asked to interpret them. Information pertaining to their experience, designation and confidence in chest radiograph interpretation was also obtained. Results: Diagnostic accuracy according to years of experience was as follows: 0 - 5 years 27.0%, 6 - 10 years 43.0%, and >10 years 47.9%. For different designations, accuracy was as follows: consultants 50.5%, registrars 40.9%, medical officers 36.4%, and interns 19.5%. Participants who were confident obtained a mean score of 39.4% and those who were not, a mean score of 31.6%. Conclusion: Chest radiographs are readily accessible and used daily in clinical practice in numerous facilities. An accurate diagnosis is important to provide quality healthcare. Improved training in interpretation for all, but especially for junior doctors, should be a priority in our training facilities. Study synopsis: What the study adds. This study tested the diagnostic accuracy with regard to common pathologies present on chest X ray by doctors rotating through, or stationed at the internal medicine department at an academic hospital. Implications of the findings. Interpretation of chest X-rays was generally poor but the study did find that this improves with experience and confidence in diagnostic ability. These findings are significant in that they indicate a need to implement improved teaching programs in radiological interpretation, especially at an undergraduate level.

Evaluation of factors and patterns influencing the 30-day readmission rate at a tertiary-level hospital in a resource-constrained setting in Cape Town, South Africa.

BACKGROUND: Factors contributing to and causes of hospital readmissions have been investigated worldwide, but very few studies have been performed in South Africa (SA) and none in the Western Cape Province. OBJECTIVES: To investigate possible preventable and non-preventable factors contributing to readmissions to the Department of Internal Medicine at Tygerberg Hospital (TBH), Cape Town, within 30 days of hospital discharge. The researchers tested a risk-stratification tool (the LACE index) to evaluate the tool's performance in the TBH system. METHODS: A retrospective analysis was conducted of all 30-day readmissions (initial hospitalisation and rehospitalisation within 30 days) to the Department of Internal Medicine at TBH for the period 1 January 2014 - 31 March 2015. Potential risk factors leading to readmission were recorded. RESULTS: A total of 11 826 admissions were recorded. Of these patients, 1 242 were readmitted within 30 days, representing a readmission rate of 10.5%. The majority of patients (66%) were readmitted within 14 days after discharge. The most important risk factor for readmission was the number of comorbidities, assessed using the Charlston score. The study also identified a large burden of potentially avoidable causes (35% of readmissions) due to system-related issues, premature discharge being the most common. Other reasons for 30-day readmission were nosocomial infection, adverse drug reactions, especially warfarin toxicity, inadequate discharge planning and physician error. CONCLUSIONS: Despite TBH being a low-resource, high-turnover system, the 30-day readmission rate was calculated at 10.5%. Global readmission rates vary from 10% to 25%, depending on the reference article/source used. We found that 35% of 30-day readmissions were potentially avoidable. Venous thromboembolism was a minor contributor to readmission but was associated with a very high mortality rate. A secondary outcome evaluated was the utility of the LACE and modified LACE (mLACE) index in the TBH environment. The risk tool performed well in the TBH population, and a high LACE and mLACE score correlated with an increased risk of 30-day readmission (p<0.001).

Evaluation of factors and patterns influencing the 30-day readmission rate at a tertiary-level hospital in a resource-constrained setting in Cape Town, South Africa

Background. Factors contributing to and causes of hospital readmissions have been investigated worldwide, but very few studies have been performed in South Africa (SA) and none in the Western Cape Province.Objectives. To investigate possible preventable and non-preventable factors contributing to readmissions to the Department of Internal Medicine at Tygerberg Hospital (TBH), Cape Town, within 30 days of hospital discharge. The researchers tested a risk-stratification tool (the LACE index) to evaluate the tool's performance in the TBH system.Methods. A retrospective analysis was conducted of all 30-day readmissions (initial hospitalisation and rehospitalisation within 30 days) to the Department of Internal Medicine at TBH for the period 1 January 2014 - 31 March 2015. Potential risk factors leading to readmission were recorded.Results. A total of 11 826 admissions were recorded. Of these patients, 1 242 were readmitted within 30 days, representing a readmission rate of 10.5%. The majority of patients (66%) were readmitted within 14 days after discharge. The most important risk factor for readmission was the number of comorbidities, assessed using the Charlston score. The study also identified a large burden of potentially avoidable causes (35% of readmissions) due to system-related issues, premature discharge being the most common. Other reasons for 30-day readmission were nosocomial infection, adverse drug reactions, especially warfarin toxicity, inadequate discharge planning and physician error.Conclusions. Despite TBH being a low-resource, high-turnover system, the 30-day readmission rate was calculated at 10.5%. Global readmission rates vary from 10% to 25%, depending on the reference article/source used. We found that 35% of 30-day readmissions were potentially avoidable. Venous thromboembolism was a minor contributor to readmission but was associated with a very high mortality rate. A secondary outcome evaluated was the utility of the LACE and modified LACE (mLACE) index in the TBH environment. The risk tool performed well in the TBH population, and a high LACE and mLACE score correlated with an increased risk of 30-day readmission (p<0.001)

Processing of the pre-beta-amyloid protein by cathepsin D is enhanced by a familial Alzheimer's disease mutation.

A major pre-beta-amyloid protein695 (APP695) processing activity from Alzheimer's disease brain extracts was identified and found to be indistinguishable from the activity of cathepsin D.APP695 processing activity cleaved APP695 into a series of fragments that reacted on immunoblots to a monoclonal antibody (C286.8a) against beta-amyloid-(1-7)-peptide and cleaved N-dansyl-APP-(591-601)-amide at the Glu-Val and Met-Asp bonds. Fragments of 5.5 kDa and 10-12 kDa were formed from the cleavage of APP695 by cathepsin D at the Glu593-Val594 bond, and had the same N-terminus as a minor form of beta-amyloid released by cells. The Lys595-->Asn and Met596-->Leu substitutions found in a pedigree of familial Alzheimer's disease, increased the cathepsin D-catalyzed rate of accumulation of 5.5 kDa and 10-12 kDa C286.8a-reactive fragments 5-10fold. This substitution also increased the rate of N-dansyl-APP-(591-601)-amide cleavage at the Xaa-Asp bond by up to 41-fold. These observations suggest a role of cathepsin D in beta-amyloid formation under certain circumstances.

Lacrimal gland uptake and metabolism of ascorbic acid.

Ascorbic acid is thought to contribute to protection against the potentially damaging effects of radiation, oxygen toxicity, and abrasion in the eye. The anterior surface of the cornea is particularly subject to insult from each threat. We considered the possibility that the lacrimal gland of pigs has transport and/or metabolic capability to sequester the reduced or oxidized form of ascorbic acid and prepare it for secretion in the tears. Slices of fresh lacrimal gland were incubated in a physiologic buffer and exposed to < or = 12 microM 14C-labeled ascorbic acid or dehydro-l-ascorbic acid over 40-min incubation periods. Dehydro-l-ascorbic acid was taken up to a greater extent than the reduced compound. 14C-Label recovered from the tissue was at least 75% in the form of ascorbic acid after incubation with either substrate. Uptake of both the reduced and oxidized substrates proceeded to a tissue to medium ratio in excess of unity; the former was prevented by the presence of nonlabeled ascorbate in the bathing medium, but was unaffected by the removal of Na+ from the bath. The uptake of both substrates was less after inhibition of cellular metabolic energy. The lacrimal gland in this diurnal animal species has transport and metabolic capabilities that could serve in secretion of ascorbic acid into tears. This might help to protect the corneal epithelium against various forms of damage.

Analysis of Creutzfeldt-Jakob disease infectious fractions by gel permeation chromatography and sedimentation field flow fractionation.

Gel permeation chromatography and sedimentation field flow fractionation (SF3) were used to further analyze highly infectious fractions from Creutzfeldt-Jakob disease (CJD) infected hamster brain. These analyses defined the relative molecular mass and physical size of the Creutzfeldt-Jakob disease (CJD) agent with greater precision than previously possible. Highly purified disaggregated fractions yielded single, homogeneous Gaussian peaks with both methods. The relevant analytical peaks contained protein-nucleic acid complexes with an M(r) of approximately 1.5 x 10(7) daltons and a mean radius of approximately 30 nm. The experimental evidence further solidifies the concept of an infectious agent that resembles a viral core rather than a simple protein.

Sequential NMR resonance assignment and structure determination of the Kunitz-type inhibitor domain of the Alzheimer's beta-amyloid precursor protein.

Certain precursor proteins (APP751 and APP770) of the amyloid beta-protein (AP) present in Alzheimer's disease contain a Kunitz-type serine protease inhibitor domain (APPI). In this study, the domain is obtained as a functional inhibitor through both recombinant (APPIr) and synthetic (APPIs) methodologies, and the solution structure of APPI is determined by 1H 2D NMR techniques. Complete sequence-specific resonance assignments (except for P13 and G37 NH) for both APPIr and APPIs are achieved using standard procedures. Ambiguities arising from degeneracies in the NMR resonances are resolved by varying sample conditions. Qualitative interpretation of short- and long-range NOEs reveals secondary structural features similar to those extensively documented by NMR for bovine pancreatic trypsin inhibitor (BPTI). A more rigorous interpretation of the NOESY spectra yields NOE-derived interresidue distance restraints which are used in conjunction with dynamic simulated annealing to generate a family of APPI structures. Within this family, the beta-sheet and helical regions are in good agreement with the crystal structure of BPTI, whereas portions of the protease-binding loops deviate from those in BPTI. These deviations are consistent with those recently described in the crystal structure of APPI (Hynes et al., 1990). Also supported in the NMR study is the hydrophobic patch in the protease-binding domain created by side chain-side chain NOE contacts between M17 and F34. In addition, the NMR spectra indicate that the rotation of the W21 ring in APPI is hindered, unlike Y21 in BPTI, showing a greater than 90% preference for one orientation in the hydrophobic groove.