Building a national hernia registry in South Africa: initial ventral hernia repair results from a diverse healthcare sector.

PURPOSE: The purpose of this paper was to introduce a new registry in a developing country by describing the demographics, management and 30-day outcomes of patients undergoing ventral hernia repair in the public and private healthcare sectors of South Africa. METHODS: This study was a retrospective review of a prospectively maintained hernia registry from the 1st of February 2019 to 29th of February 2020. RESULTS: 353 ventral hernia repair cases were recorded of which 47% were incisional hernias and the remainder were primary hernias. The median age was 54 years with even distribution of males and females. Half of the patients were obese with a median BMI of 31 kg/m2. The private sector performed 190 cases (54%) and the public sector 163 cases (46%). The public sector had more current smokers undergoing elective repairs, 28% vs 15%, p = 0.01 and performed more emergency repair cases, 21% vs 8%, p < 0.01. The majority (89%) of hernias were repaired with mesh and one-third were repaired laparoscopically. 30 day follow up was obtained in 30% of cases, the private sector had better follow up rates (42% vs 14%). CONCLUSION: Participation in the HIG (SA) registry was low with poor follow up over the first year. Ongoing prospective data capture on the HIG (SA) hernia registry will continue to provide further insights into hernia repair practices in South Africa.

Simultaneous measurement of whole blood vitamin B1 and vitamin B6 using LC-ESI-MS/MS.

Vitamin B1 and B6 have recently been included in the Dutch clinical guidelines for the general practitioner in the differential diagnosis of dementia. To keep up with the sharp rise in the number of requests, an LC-MS/MS method using stable isotopes as internal standards was developed. The active vitamers thiamine pyrophosphate (TPP) and pyridoxal-5'-phosphate (PLP) in whole blood are simultaneously measured with a short run time of 2min. Whole blood is mixed with internal standard solution containing both TPP-d3 and PLP-d3, followed by deproteinization with a trichloroacetic acid (TCA) solution. A UPLC-MS/MS system from Waters™ was used for chromatographic separation and subsequent detection by electrospray ionization in the positive mode with mass transitions of 425.1>121.85 for TPP and 247.9>149.9 for PLP. The method is linear across the range of 12-4870 nmol/L for TPP and 6-4850 nmol/L for PLP. The mean intra-assay and inter-assay precision are 3.5% and 7.6% respectively for TPP and 3.4% and 6.1% for PLP. The relative matrix effect (TPP 97%, PLP 93%), recovery (TPP 99%, PLP 94%) and lower limit of quantification (TPP 12 nmol/L, PLP 6 nmol/L) meet the applied acceptance criteria. The comparison of the new LC-ESI-MS/MS method for TPP with our current HPLC-Fluorescence method for total thiamine yields the following equation: TPP LC-MS/MS=0.97×total thiamine HPLC - 10.61 (r2=0.94). The comparison of the new LC-ESI-MS/MS method for PLP with our current LC-ESI-MS/MS method results in PLP LC-MS/MS new=1.01×PLP LC-MS/MS old - 1.58 (r2=0.99). In conclusion, this LC-MS/MS based assay is characterized by simple sample processing with a short run time and comparison with the current methods is excellent. The new LC-MS/MS method is a convenient method to determine TPP and PLP in whole blood for both clinical routine and research applications.

The prosthetic group of methylamine dehydrogenase from Pseudomonas AM1: evidence for a quinone structure.

The g-value and linewidth of ESR spectra of methylamine dehydrogenase (primary-amine:(acceptor) oxidoreductase (deaminating) EC 1.4.99.-) and methanol dehydrogenase (alcohol:(acceptor) oxidoreductase, EC 1.1.99.8) are very similar. This similarity is also reflected in electron-nuclear double resonance (ENDOR) results, the coupling constants of two protons in one enzyme equalling those in the other. The presence of a third proton in the ENDOR spectrum of methylamine dehydrogenase suggests a different structure or a different kind of interaction which can be related to the finding that the resolved ROSTHETIC GROUP IS PROTEIN-BOUND. The bound prosthetic group has a high redox-potential, supporting the conclusion from the ESR and ENDOR results that it is a quinone derivative.

Reduced lipid contamination in in vivo 1H MRSI using time-domain fitting and neural network classification.

It is a well-known problem that metabolite maps, reconstructed from in vivo 1H MRSI data sets, may suffer from contamination caused by the presence of strong lipid signals. In the present investigation, the lipid problem was addressed by applying specific signal processing and data-analysis techniques, combined with pattern recognition based on the concept of the artificial neural network. In order to arrive at images, cleaned from lipid artifacts, we have applied our previously introduced iterative and noniterative time-domain fitting procedures. Furthermore, reduction in computational time of the image reconstructions could be realized by using information provided by a neural network classification of the spectra, calculated from the MRSI data sets.

Quality assessment in in vivo NMR spectroscopy: VI. Multicentre quantification of MRS test signals.

In this paper the results are presented of a joint European quantitative data-analysis study on a series of in vivo NMR time-domain test signals. The purpose of this study was to investigate, whether the quantitative MRS results from the various European biomedical research-centres can be made more comparable and reproducible. From the results of the study it can be concluded that in case of heavily overlapping NMR lines the quantifications should be done by some form of model function fitting and that, whenever possible, prior knowledge on the quantitative parameters should be incorporated into the quantification algorithms.

Absolute metabolite quantification by in vivo NMR spectroscopy: V. Multicentre quantitative data analysis trial on the overlapping background problem.

The goal of this study was to establish the best approach for quantifying nuclear magnetic resonance (NMR) lines, that in the frequency domain are overlapping with broad, unwanted background features. To perform the quantitative data analysis in a controlled way, test signals were designed and utilised, derived from two different real-world in vivo nuclear magnetic resonance signals. One of the main conclusions of the study was that the quantification methods currently available to the biomedical research groups can deliver the correct values of the quantitative parameters, but that great care should be taken in using optimal input parameters for the computer programs concerned.

A distributed computing system for magnetic resonance imaging: Java-based processing and binding of XML.

Recently we have developed a Java-based heterogeneous distributed computing system for the field of magnetic resonance imaging (MRI). It is a software system for embedding the various image reconstruction algorithms that we have created for handling MRI data sets with sparse sampling distributions. Since these data sets may result from multi-dimensional MRI measurements our system has to control the storage and manipulation of large amounts of data. In this paper we describe how we have employed the extensible markup language (XML) to realize this data handling in a highly structured way. To that end we have used Java packages, recently released by Sun Microsystems, to process XML documents and to compile pieces of XML code into Java classes. We have effectuated a flexible storage and manipulation approach for all kinds of data within the MRI system, such as data describing and containing multi-dimensional MRI measurements, data configuring image reconstruction methods and data representing and visualizing the various services of the system. We have found that the object-oriented approach, possible with the Java programming environment, combined with the XML technology is a convenient way of describing and handling various data streams in heterogeneous distributed computing systems.

Java-based graphical user interface for MRUI, a software package for quantitation of in vivo/medical magnetic resonance spectroscopy signals.

This article describes a Java-based graphical user interface for the magnetic resonance user interface (MRUI) quantitation package. This package allows MR spectroscopists to easily perform time-domain analysis of in vivo/medical MR spectroscopy data. We have found that the Java programming language is very well suited for developing highly interactive graphical software applications such as the MRUI system. We also have established that MR quantitation algorithms, programmed in the past in other languages, can easily be embedded into the Java-based MRUI by using the Java native interface (JNI).

Preferential protection of Borrelia burgdorferi sensu stricto by a Salp15 homologue in Ixodes ricinus saliva.

BACKGROUND: Ixodes ticks are the main vectors for Borrelia burgdorferi sensu lato. In the United States, B. burgdorferi is the sole causative agent of Lyme borreliosis and is transmitted by Ixodes scapularis. In Europe, 3 Borrelia species-B. burgdorferi, B. garinii, and B. afzelii-are prevalent, which are transmitted by Ixodes ricinus. The I. scapularis salivary protein Salp15 has been shown to bind to B. burgdorferi outer surface protein (Osp) C, protecting the spirochete from antibody-mediated killing. METHODS AND RESULTS: We recently identified a Salp15 homologue in I. ricinus, Salp15 Iric-1. Here, we have demonstrated, by solid-phase overlays, enzyme-linked immunosorbent assay, and surface plasmon resonance, that Salp15 Iric-1 binds to B. burgdorferi OspC. Importantly, this binding protected the spirochete from antibody-mediated killing in vitro and in vivo; immune mice rechallenged with B. burgdorferi preincubated with Salp15 Iric-1 displayed significantly higher Borrelia numbers and more severe carditis, compared with control mice. Furthermore, Salp15 Iric-1 was capable of binding to OspC from B. garinii and B. afzelii, but these Borrelia species were not protected from antibody-mediated killing. CONCLUSIONS: Salp15 Iric-1 interacts with all European Borrelia species but differentially protects B. burgdorferi from antibody-mediated killing, putatively giving this Borrelia species a survival advantage in nature.

Evaluation of five protocols for quantification of two-dimensional MR spectroscopic images.

Five protocols were tested for quantification on in vivo two-dimensional spectroscopic imaging datasets. The datasets are duplo measurements from three individuals. The peaks for N-acetyl aspartate, creatines, and cholines were quantified. The first of the protocols is conventional integration of a selected interval around the peak. The others are various implementations of a Gauss-Newton-based least-squares time-domain fitting algorithm. Fitting a half-echo (free-induction decay curve, FID) to a full echo was compared; this was combined with or without filtering out the water signal using the Lanczos-Hankel singular-value decomposition (LHSVD). It appears that conventional integration yields consistent and accurate results in comparison to the fitting methods. The combination of LHSVD and echo fitting performs equally well; advantages and disadvantages are discussed. The protocols using FID fitting perform poorly with these experimental datasets.

An electron-nuclear double-resonance study of methanol dehydrogenase and its coenzyme radical.

Proton as well as deuteron ENDOR (electron-nuclear double resonance) spectroscopy were performed of methanol dehydrogenase and pyrrolo-quinoline semiquinone (PQQH). Samples were examined in H2O- and 2H2O-containing buffers at 4.2 degrees K with Ka-band (33.5 GHz) frequency. Measurements of the enzyme in 2H2O revealed that the signals observed around the proton free-precession frequency belong to exchangeable protons. Therefore, our earlier assumption (R. de Beer et al. (1979) J. Chem. Phys. 70, 4491-4495) that these signals originate from protons in the aromatic ring of PQQH is incorrect. The proton matrix signal of the enzyme in H2O and 2H2O are nearly similar, while a deuteron matrix signal is not observed in the latter case. It is concluded, therefore, that the coenzyme is situated in a hydrophobic site of the enzyme.

Post-ischemic contractile dysfunction does not correlate with an elevated intracellular free [Mg2+]: a 31P-NMR study on isolated rat and rabbit hearts.

The aim of this study was to investigate whether intracellular free Mg2+ (Mgr), which increases during myocardial ischemia due to hydrolysis of ATP, remained elevated during reperfusion after a relatively short period of ischemia and thereby could account for temporary post-ischemic contractile dysfunction, often referred to as stunning. 31P-magnetic resonance (31P-NMR) spectroscopy was used to follow creatine phosphate, adenosine triphosphate, intracellular inorganic phosphate, intracellular pH and Mgr simultaneously with left ventricular developed pressure (LVDP) and coronary flow in isolated rat and rabbit hearts, which were perfused (37 degrees C) according to Langndorff. LVDP was measured in an isovolumic way by means of an intraventricular latex balloon. Rat hearts (300 beats/min) were made globally ischemic for 15 min and rabbit hearts (180 beats/min) for 15 or 20 min. All hearts were reperfused for 60 min. Control hearts were perfused for 75 min without being made ischemic. During ischemia Mgr (mmol/l) increased from 0.76 +/- 0.20 to 4.34 +2- 1.99 in the rat hearts, and from 0.72 +/- 0.22 to 2.18 +/- 1.06 (15 min) and 2.35 +/- 1.26 (20 min) in the rabbit hearts. During reperfusion Mgr in the three groups returned to the level of the control hearts within 7.5 min, and LVDP within 25 min. At the end of the reperfusion period ATP content amounted to 56 +/- 17% (rat hearts), 66 +/- 10% (rabbit hearts; 15 min ischemia group) and 61 +/- 7% (rabbit hearts; 20 min ischemia group) of the pre-ischemic levels. The results confirm that in vitro stunning is a short-lived phenomenon and indicate that an increased Mgr is not involved in this temporary mechanical dysfunction.

Saturation correction in human cardiac 31P MR spectroscopy at 1.5 T.

This study was conducted to verify the validity of using saturation factors obtained from unlocalized 31P spectra containing both chest wall and heart muscle signals for correcting human heart muscle phosphocreatine/beta-adenosine triphosphate (PCr/beta-ATP) ratios. Saturation factors and T1 relaxation times were determined from 31P magnetic resonance spectra of human chest wall and heart muscle simultaneously in healthy volunteers using one-dimensional spectroscopic imaging in combination with a two-dimensional ISIS sequence by using adiabatic 180 degrees inversion and adiabatic 90 degrees excitation pulses at 1.5 T. Blood corrected saturation factors for PCr/beta-ATP at a TR of 2.4 s were significantly different in heart muscle and chest wall muscle, 1.30 +/- 0.25 and 1.73 +/- 0.31, respectively (p < 0.05). T1 values for PCr and beta-ATP in heart muscle were 4.28 +/- 0.72 and 2.99 +/- 0.52 and in chest wall muscle 6.82 +/- 1.07 and 3.39 +/- 0.48, respectively. The T1(PCr)/T1(beta-ATP) ratios in chest wall and heart muscle were not identical. The mean PCr/beta-ATP ratios in heart and chest wall muscle of six healthy volunteers were 1.23 +/- 0.17 and 3.71 +/- 0.53, respectively.

Neurotensin, vaso-active intestinal polypeptide and gastrin levels in plasma and portal venous blood in experimental mesenteric ischaemia.

The effect of mesenteric ischaemia on the levels of neurotensin, vaso-active intestinal polypeptide and gastrin in portal venous blood and in the peripheral circulation was studied in two groups of 7 and 6 baboons (Papio ursinus). In peripheral blood a decreasing trend in levels of neurotensin was observed, while vaso-active intestinal polypeptide and gastrin levels were unchanged. There was a similar trend in neurotensin levels in portal venous blood, together with an increasing trend in levels of vaso-active intestinal polypeptide. Gastrin levels were unchanged. Further investigation of these apparent trends in a large number of animals is warranted.

Accurate quantification of in vivo 31P NMR signals using the variable projection method and prior knowledge.

Free induction decay signals are analyzed by fitting a model function directly in the time domain. No starting values are needed for linear model parameters, and omission of corrupted data points poses no problems. A significant gain of accuracy is achieved by imposing prior knowledge about the model parameters.

Fast Removal of Residual Water in Proton Spectra.

Quantification of metabolites in 1H spectra is difficult because of the presence of an unwanted water signal. Preprocessing, or removing the water contribution of a 1H spectrum, in the time domain is usually done using the state-space approach HSVD. HSVD removes the residual water and its side lobes, thereby reducing the baseline for the metabolites of interest and allowing subsequent data analysis using more sophisticated nonlinear least squares algorithms. However, the HSVD algorithm is computationally expensive because it estimates the signal subspace using the singular value decomposition (SVD). We show here that replacing the SVD by a low-rank revealing decomposition speeds up the computations without affecting the accuracy of the wanted parameter estimates. Copyright 1998 Academic Press.

Anti-Gerbich antibodies and Gerbich-negative Dantu-positive red blood cells in a woman from South Africa.

Anti-Gerbich type anti-Ge3 antibodies were identified in the serum of a woman of mixed ethnic origin from Cape Town. The woman had type Ge:-2,-3 (Gerbich) red cells on which there was no evidence of weakened Kell antigens. Her red cells were also Dantu-positive.