The human vermiform appendix: morphological and anatomical review

The article covers aspects of morphological, anatomical, embryological, histological aspects and origin, types, blood supply, innervation, lymph drainage of human vermiform appendix. The purpose of the study is to understand real function and to summarize this information for positive impact on clinical decision in case of appendicitis. Although characteristic features of normal and diseased appendix have been reported for many previous centuries, it still the most common challenge facing every day in operation room. The appendectomy, commonest surgical emergency procedure, may cause little confusion in surgeons due to highly variable situations of it inside the abdominal cavity. However, the recent imaging techniques have increased ability of surgeon for crucial diagnosis of the diseased appendix.

25-hydroxyvitamin D is a predictor of COVID-19 severity of hospitalized patients

Objectives

Studies investigating the association between vitamin D and severity of COVID-19 have mixed results perhaps due to immunoassay assessment of total 25-hydroxyvitamin D (tD) (the sum of 25-hydroxyvitamin-D2 [25-OH-D2] and 25-hydroxyvitamin-D3 [25-OH-D3]). Liquid chromatography tandem mass spectrometry (LC-MS/MS) has high analytical specificity and sensitivity for 25-OH-D2 and 25-OH-D3, and thus enables a more accurate assessment of impact on COVID-19 outcomes.

Methods

We established reference intervals for 25-OH-D3 and tD using LC-MS/MS. 25-OH-D2, 25-OH-D3 and tD were quantitated for 88 COVID-19 positive and 122 COVID-19 negative specimens. Chi-square or Fisher’s exact tests were used to test associations in binary variables. T-Tests or Wilcoxon rank sum tests were used for continuous variables. Cox proportional hazards were used to test associations between 25-OH-D3 or tD levels and length of stay (LOS). For mortality and ventilation, logistic regression models were used.

Results

COVID-19 patients with deficient (<20 ng/mL) levels of 25-OH-D3 had significantly longer LOS by 15.3 days. COVID-19 P patients with deficient (<20 ng/mL) and insufficient (<30 ng/mL) of tD had significantly longer LOS by 12.1 and 8.2 days, respectively. Patients with insufficient levels of tD had significantly longer LOS by 13.7 days. COVID-19 patients with deficient serum 25-OH-D3 levels had significantly increased risk-adjusted odds of in-hospital mortality (OR [95% CI]: 5.29 [1.53–18.24]); those with insufficient 25-OH-D3 had significantly increased risk for requiring ventilation during hospitalization was found at LCMS insufficient cutoff (OR [95% CI]: 2.75 [1.10–6.90]).

Conclusions

There is an inverse relationship of 25-hydroxyvitamin D levels and hospital LOS for COVID-19 patients. Vitamin D status is a predictor for severity of outcomes. LCMS results are useful for assessing the odds of mortality and the need for ventilation during hospitalization.

Analytical and Clinical Performance Evaluation of the Elecsys HIV combi PT Assay on the cobas e 602 Analyzer for the Diagnosis of Human Immunodeficiency Virus

OBJECTIVES

We evaluated the performance of the Elecsys HIV combi PT assay on the cobas e 602 analyzer for diagnosing human immunodeficiency virus (HIV; part of the US Food and Drug Administration [FDA] submission).

METHODS

The HIV combi PT and reference (ARCHITECT HIV Ag/Ab Combo) assays were assessed at four independent clinical laboratories/one reference laboratory (United States; July 2014 to November 2015). Clinical performance was evaluated using four reagent lots. Analytical performance was evaluated per Clinical and Laboratory Standards Institute EP05-A3 guidelines. Serum/plasma samples from 18 clinical sites/vendors (United States and outside the United States) were tested.

RESULTS

Sensitivity (95% confidence interval [CI]) in HIV-1 antibody-positive individuals (United States and outside the United States; n = 1,460) was 100.00% (99.75%-100.00%). Specificity was 99.94% (95% CI, 99.85%-99.98%) in low-risk individuals (United States; n = 6,843), 98.19% (95% CI, 96.93%-99.04%) in high-risk individuals (United States and outside the United States; n = 758), and 97.43% (95% CI, 95.32%-98.76%) in pregnant women (United States and outside the United States; n = 440). Analytical performance was acceptable.

CONCLUSIONS

We demonstrate the robustness of the FDA-approved Elecsys HIV combi PT assay on the cobas e 602 analyzer for HIV testing in the United States.

Activation of retinoid receptor-mediated signaling ameliorates diabetes-induced cardiac dysfunction in Zucker diabetic rats

Diabetic cardiomyopathy (DCM) is a significant contributor to the morbidity and mortality associated with diabetes and metabolic syndrome. Retinoids, through activation of retinoic acid receptor (RAR) and retinoid x receptor (RXR), have been linked to control glucose and lipid homeostasis, with effects on obesity and diabetes. However, the functional role of RAR and RXR in the development of DCM remains unclear. Zucker diabetic fatty (ZDF) and lean rats were treated with Am580 (RARα agonist) or LGD1069 (RXR agonist) for 16 weeks, and cardiac function and metabolic alterations were determined. Hyperglycemia, hyperlipidemia and insulin resistance were observed in ZDF rats. Diabetic cardiomyopathy was characterized in ZDF rats by increased oxidative stress, apoptosis, fibrosis, inflammation, activation of MAP kinases and NF-κB signaling and diminished Akt phosphorylation, along with decreased glucose transport and increased cardiac lipid accumulation, and ultimately diastolic dysfunction. Am580 and LGD1069 attenuated diabetes-induced cardiac dysfunction and the pathological alterations, by improving glucose tolerance and insulin resistance; facilitating Akt activation and glucose utilization, and attenuating oxidative stress and interrelated MAP kinase and NF-κB signaling pathways. Am580 inhibited body weight gain, attenuated the increased cardiac fatty acid uptake, β-oxidation and lipid accumulation in the hearts of ZDF rats. However, LGD1069 promoted body weight gain, hyperlipidemia and cardiac lipid accumulation. In conclusion, our data suggest that activation of RAR and RXR may have therapeutic potential in the treatment of diabetic cardiomyopathy. However, further studies are necessary to clarify the role of RAR and RXR in the regulation of lipid metabolism and homeostasis.

Comparison of analytical and clinical performance of three methods for detection of Clostridium difficile

CONTEXT

Diagnostic laboratory testing for Clostridium difficile infection has undergone considerable and rapid evolution during the last decade. The ideal detection method(s), which should exhibit high analytical and clinical sensitivity and specificity, remains undefined.

OBJECTIVE

We sought to evaluate the analytical and clinical performance characteristics of three methods for the laboratory detection of C difficile.

DESIGN

This study used 114 consecutive stool samples to compare three methods of C difficile detection: an enzyme immunoassay (EIA) for toxins A/B, a lateral flow membrane immunoassay for glutamate dehydrogenase (GDH), and a qualitative real-time polymerase chain reaction (PCR) assay. Medical records of all patients having ≥1 positive test result were reviewed to estimate the clinical likelihood of C difficile infection.

RESULTS

Based upon laboratory result consensus values, analytical sensitivity was significantly higher for GDH (94%) and PCR (94%) assays than for toxin EIA (25%). Analytical specificity was significantly higher for PCR (100%) and EIA (100%) than for GDH assay (93%). In contrast, assay performance based upon clinical probability of C difficile infection suggested lower discriminatory power (ie, clinical specificity) of the more analytically sensitive methods.

CONCLUSIONS

Higher rates of C difficile detection will be realized upon implementation of GDH assay and/or real-time PCR-based testing algorithms than by testing with EIA alone. Further study is required to elucidate potential downstream costs for higher detection rates.

The impact of routine histopathological examination on cholecystectomy specimens from an Asian demographic

INTRODUCTION

Most gallbladder carcinoma cases are suspected pre-operatively or intra-operatively. In Malaysia histopathological examination of cholecystectomy specimens has become routine practice. The aim of this study was to assess the impact of routine histological examinations on cholecystectomy specimens from an Asian demographic, which may differ from a Caucasian demographic.

METHODS

A retrospective study was performed of all histopathology reports for cholecystectomies (laparoscopic and open) undertaken over a period of 12 years (1997-2008) in a single teaching hospital.

RESULTS

A total of 1,375 gallbladder specimens were sent for histopathological analysis, with 7 (0.5%) being reported as malignant while only three (0.2%) were found to contain primary gallbladder carcinoma. Other premalignant findings included two specimens with dysplastic changes of the mucosa and one tubulovillous adenoma with a dysplastic epithelium. From the ten malignant and premalignant specimens, seven were diagnosed pre-operatively, two were suspected intra-operatively and one was diagnosed with dysplastic changes on the histopathology report post-operatively.

CONCLUSIONS

This study supports earlier research carried out in the UK and the demographic difference does not affect the impact of the histology examination on cholecystectomy specimens in diagnosing this disease. A selective policy is recommended in Malaysia.

Hyperbilirubinemia and Transcutaneous Bilirubinometry

Background: Neonatal jaundice or hyperbilirubinemia is a common occurrence in newborns. Although most cases of neonatal jaundice have a benign course, severe hyperbilirubinemia can lead to kernicterus, which is preventable if the hyperbilirubinemia is identified early and treated appropriately.

Content: This review discusses neonatal jaundice and the use of transcutaneous bilirubin (TcB) measurements for identification of neonates at risk of severe hyperbilirubinemia. Such a practice requires appropriate serial testing and result interpretation according to risk level from a nomogram that provides bilirubin concentrations specific for the age of the neonate in hours. In this context, we have evaluated the potential impact on clinical outcome and limitations of TcB methods in current use.

Summary: TcB measurement is a viable option in screening neonates to determine if they are at risk for clinically significant hyperbilirubinemia. Total serum bilirubin should be measured by a clinical laboratory if a newborn is shown to be at higher risk for clinically significant hyperbilirubinemia. In addition, external quality assessment to identify biases and operator training issues should be part of any TcB monitoring program.

Quality improvement programme for diabetes care in family practice settings in Dubai

A continuous quality improvement programme for the care of registered diabetes patients was introduced in 16 government-affiliated primary health care centres in Dubai. Quality improvement teams were formed, clinical guidelines and information systems were developed, diabetes nurse practitioners were introduced and a team approach was mobilized. Audits before and after the introduction of the scheme showed significant improvements in rates of recording key clinical indicators and in their outcomes. For example, the proportion of patients with glycosylated haemoglobin levels < 7% increased from 20.6% to 31.7% and with LDL cholesterol < 100 mg/dL increased from 20.8% to 33.6%. Mean systolic blood pressure of registered patients fell from 135.3 mmHg to 133.2 mmHg.

Masking and bondage in suicidal hanging: a case report

The body of a 35-year-old man was found hanging in a relatively isolated place outdoors. A vest was wrapped over his head, neck and lower part of the face. The hands were loosely tied in front of the body. The vest was tucked between the neck and the ligature, to act as a pad. Thorough scene examination and post-mortem examination excluded any evidence of foul play. Although bondage is usually associated with autoerotic practices in asphyxiation deaths, it was established that this case was a suicide. DNA was used as a supportive measure to determine that the handkerchief and vest belonged to the deceased.

Antibodies and Fab fragments protect Cu,Zn-SOD against methylglyoxal-induced inactivation

Methyl glyoxal (MG) is a highly reactive alpha-oxoaldehyde that plays an important role in non-enzymatic glycosylation reactions, formation of Advanced Glycation End products (AGEs) and other complications associated with hyperglycemia and related disorders. Unlike sugars, glycation by MG is predominantly arginine directed, which is particularly more damaging since arginine residues have a high-frequency occurrence in ligand and substrate recognition sites in receptor and enzyme active sites. Using bovine erythrocyte Cu,Zn-superoxide dismutase (SOD) as model enzyme, the potential of anti-enzyme antibodies in imparting protection against MG-induced inactivation was investigated. A concentration- and time-dependent inactivation of SOD was observed when the enzyme was incubated with MG. The enzyme lost over 80% activity on incubation with 5 mM MG for 5 days. More marked inactivation was observed in 24 h when the MG concentration was raised up to 30 mM. The SOD inactivation was accompanied by the formation of high molecular weight aggregates as revealed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and surface enhanced laser desorption/ionization time of flight mass spectrometry (SELDI/TOF mass spectrometry). Inclusion of specific anti-SOD antibodies raised in rabbits or monomeric Fab fragments derived thereof offered remarkable protection against MG-induced loss in enzyme activity. The protection, however, decreased with increase in the concentration of MG. SELDI/TOF mass spectrometry also revealed that the antibodies restricted the formation of high molecular weight aggregates. The results emphasize the potential of antibody based therapy in combating glycation and related complications.

Analytical evaluation of HgbA1c, microalbumin, CRP, and RF on Architect ci8200 integrated system and workflow performance evaluation using computer simulation

BACKGROUND

Recently, hemoglobin A1c (HgbA1c), microalbumin (MA), C-reactive protein (CRP) and rheumatoid factor (RF) have been introduced on high throughput general chemistry system. We evaluated analytical performance of these assays on an integrated clinical chemistry and immunoassay analyzer and studied the impact of testing these assays on these systems on the overall efficiency of the analyzer, via computer simulation.

METHODS

The analytical performance was measured by determining precision, linearity and correlation of patient sample results with in-house testing methodology. MedModel simulation software is used to develop simulation model and process efficiency is determined by measuring turnaround times and resource utilization.

RESULTS

Between-days CVs ranged from 8.59% for MA to 3.22% for HgbA1c level 1 controls. Less than 2% carryover for all 4 methods was observed on the integrated analyzer. For HgbA1c on HPLC analyzer, the minimum and maximum TAT for a batch of 50 samples was 3.78 and 160 min, respectively, while for the integrated system it was 28.2 and 35.1 min, respectively. Labor utilization for the 2 processes ranged from 3.21% to 3.75%.

CONCLUSION

Chemistry module on an integrated system can be used to determine the HgbA1c and other serum proteins.

Differential protein expression profiles of gastric epithelial cells following Helicobacter pylori infection using ProteinChips

Helicobacter pylori infects approximately half of the world's population and the bacterium is associated with gastric cancer and peptic and duodenal ulcers. In this study, Surface Enhanced Laser Desorption /Ionization time-of-flight mass spectrometry (SELDI-TOF-MS) was used to identify the biomarkers from H. pylori infected gastric epithelial cells (GEC) to understand key mechanisms associated with pathogenesis. Using different chip surfaces, differential protein expression profile of GEC was obtained and several upregulated or downregulated biomarkers were detected on GEC, following H. pylori infection. Four different H. pylori infected GECs were compared based on their expression of MHC class II, a receptor reported to trigger apoptosis. One biomarker was identified in H. pylori infected GEC as Annexin A2 (Annexin II) from the flow through of the anion-exchange resin. The increased expression of Annexin II in GEC following H. pylori infection was further confirmed by Western Blot analyses and indicates its involvement in H. pylori pathogenesis.

Association of transcutaneous bilirubin testing in hospital with decreased readmission rate for hyperbilirubinemia

BACKGROUND

Newborns are being discharged from hospitals within 1-2 days of birth, before hyperbilirubinemia usually becomes clinically evident. We investigated the use of transcutaneous bilirubin (TcB) before discharge to determine whether it affects the use of laboratory bilirubin testing or decreases the number of neonates readmitted for hyperbilirubinemia within 7 days of initial discharge.

METHODS

We retrospectively searched a clinical laboratory and hospital database to determine the number of births, newborn readmission rates for hyperbilirubinemia, length of stay, and the number of bilirubin measurements in the clinical laboratory ordered for all babies in the newborn unit at the University of Texas Medical Branch from August 2002 to March 2003 (before TcB testing) and from May 2003 to December 2003 (after TcB).

RESULTS

Between August 2002 and December 2003, 8974 newborns (both vaginal and cesarean births) were admitted to the newborn nursery. Babies who did not fit the diagnosis-related group criteria of "normal newborn" were removed, leaving 6933 babies who were included in the study. April was considered a transition month and was not included in the study, leaving 6603 newborns to be included. Of these, 446 (6.8%) required phototherapy for treatment of hyperbilirubinemia before initial discharge. For the 8 months before and 8 months after initiation of TcB testing, the number of laboratory bilirubin measurements ordered per newborn did not change, nor did the mean (SD) length of stay for normal newborns [2.15 (1.1) days vs 2.12 (1.1) days; P = 0.53], nor days of treatment with phototherapy before discharge [2.9 (1.3) days vs 2.9 (1.3) days; P = 0.67]. By contrast, the number of readmissions per 1000 newborns per month for clinically significant hyperbilirubinemia decreased significantly (Wilcoxon rank-sums two-sample test, P = 0.044), from 4.5 (2.4) to 1.8 (1.7) after TcB testing was initiated.

CONCLUSION

Access to TcB testing is associated with a reduction in the hospital readmission rate for hyperbilirubinemia within 7 days of the initial discharge.

Multiple site analytical evaluation of a portable blood gas/electrolyte analyzer for point of care testing

OBJECTIVE

To evaluate the analytical performance of the SenDx 100 portable blood gas and electrolyte analyzer (SenDx Medical, Carlsbad, CA).

DESIGN

Accuracy was evaluated by correlation of whole blood patient samples with the Nova Stat Profile 5 (Nova Biomedical, Waltham, MA) and the Ciba Corning 865 (Chiron Diagnostics, Medford, MA). Precision was evaluated using quality control materials (RNA Medical, Acton, MA).

SETTING

Critical care laboratories and operating rooms in two institutions.

MEASUREMENTS AND MAIN RESULTS

Precision studies performed at three different concentration levels for each analyte demonstrated intra-assay precision of < or =2.5% coefficient of variation and interassay precision of < or =4.0% coefficient of variation in all cases. Analysis of patient specimens in general showed good to excellent correlation to reference analyzers. Regression variables are tabulated.

CONCLUSIONS

The SenDx 100 portable blood gas and electrolyte analyzer is a simple and easy to use analyzer demonstrating acceptable performance compared with reference methods.

Prospective study of IgM to Toxoplasma gondii on Beckman Coulter's Access(TM) immunoassay system and comparison with Zeus ELISA and gull IFA assays

We compared a new assay for Toxoplasma IgM on the Access analyzer (Beckman Coulter, Inc., Chaska, MN, USA), a random access instrument based on the principle of paramagnetic particle enzyme immunoassay with an enzyme-linked immunosorbent assay (ELISA) (Zeus Scientific, Inc., Raritan, NJ, USA) and an immunofluorescent assay (IFA) (Gull Laboratories, Inc., Salt Lake City, UT, USA). Four hundred fresh, unfrozen clinical samples from pregnant women (n = 154), HIV positive patients (n = 41), and patients in whom infection with Toxoplasma gondii was suspected (n = 200) were collected and assayed over a three month period. The specificity of the Access assay was compared to the consensus results. Results that were discrepant between the ELISA and IFA were resolved using a third IFA (Zeus). Once resolved, the specificity for the Access assay, the Zeus ELISA and the Gull IFA were 99.22%, 97.91%, and 99.45%, respectively. We conclude that the Access assay specificity is comparable to consensus results, minimizing false positive results; and because it is a random access instrument, it may be preferable over batch methods.

Apparatus and method for interfacing capillary electrophoresis and chemiluminescence nitrogen detection for the analysis of nitrogen-containing compounds

We have developed an interface that allows the specific detection of nitrogen-containing compounds by using a chemiluminescence nitrogen detector. The feasibility of using this interface was demonstrated by separating and detecting two nitrogen-containing compounds, p-aminosalicylic acid and L-phenylalanine. Although baseline separation was achieved, the theoretical plates were lower when compared to UV detection (25000 vs. approximately 85000). A sensitivity of 75 ng (approximately 500 pmol) per injection was achieved with this system which is adequate for pharmaceutical and biotech applications.

Development of a urinary free cortisol assay using solid-phase extraction-capillary electrophoresis

In clinical practice, the measurement of urinary free cortisol (UFC) provides the most sensitive and specific diagnostic information for excess adrenal production of cortisol. The existing methodologies (RIA and HPLC) are time consuming, costly, involve tedious extractions, derivatizations and problems with non-specific interactions with cortisol metabolites in urine. In the present study, we describe the development of an SPE-CE method for the rapid analysis of UFC. UFC was concentrated using SPE C18 cartridges (3M Empore) under a vacuum and eluted with acetonitrile-SDS. The use of 10% acetone to wash cartridges before final elution with acetonitrile-SDS showed significant improvements in the free cortisol recovery. The complete extraction was accomplished in 10-15 min with a recovery of 89-94%. CE analysis was done on a Beckman P/ACE 5010 with detection at 254 nm using a neutral capillary. Detection limits of free cortisol in urine was improved to 10 microg/l with SPE compared to 500 microg/l without SPE. No interferences either from BSA or other urinary cortisol metabolites affected the free cortisol determinations. The results showed the feasibility of a rapid UFC detection with improved sample handling capacity.

Evaluation of immuno-1 toxoplasma IgG assay in the prenatal screening of toxoplasmosis

We evaluated the Immuno-1 (Bayer Diagnostics, Tarrytown, New York, USA) and IMx (Abbott Laboratories, Chicago, Illinois, USA) toxoplasma IgG assays in 298 (223 fresh in-house prenatal + 75 supplied by Bayer) specimens over 15 days. Discordant results were resolved by indirect fluorescence assay (Gull Laboratories, Salt Lake City, Utah, USA). The performance of Immuno-1 assay was found to be comparable to the IMx assay. Immuno-1, being a random access analyzer with minimum hands-on time requirements may have an advantage in the overall laboratory efficiency.

Laser induced resonance energy transfer--a novel approach towards achieving high sensitivity in capillary electrophoresis. I. Clinical diagnostic application

Most of the procedures currently performed by capillary zone electrophoresis (CZE) with laser induced fluorescence detection requires prior derivatization. This increases cost, the turn-around-time and chances of extraneous contaminations. CZE with laser induced resonance energy transfer is demonstrated as a viable alternative for detecting non-fluorescent compounds with no prior derivatization. The feasibility of this approach is demonstrated by separating and directly detecting salicylic acid (2,4-dihydroxybenzoic acid), gentisic acid (o-methoxybenzoic acid), salicyluric acid (o-hydroxyhippuric acid) and 4-aminosalicylic acid in urine. The detection of salicylate in serum is also shown. The method is highly sensitive with detection limits in the 1.10(-7) M range. Importantly it requires no prior preconcentration or sample preparation and can be used with complex sample matrices such as serum and urine.

Ultrastructural and morphometrical studies on the reticular framework and reticular fibers in the reticuloendothelial system of rats

The reticular framework and reticular fibers in the thymus, cervical lymph node, spleen and bone marrow of Wistar rats were studied by transmission electron microscopy and morphometrical method. The reticular framework was usually observed in these organs as a common structure that consisted mainly of the slender cytoplasmic processes of the fibroblastic reticular cells interconnected with tight junction. Ultrastructurally, the reticular fibers were a mixture of collagen fibrils and amorphous materials, and were almost completely ensheathed by the cytoplasm of fibroblastic reticular cells. Such characteristic structure of the reticular fibers was found not only in the thymus, lymph node and spleen, but also in the bone marrow where it has not been clearly demonstrated previously. Morphometrical analysis revealed that the content of collagen fibrils in the reticular fiber in the lymphoid tissues (the thymus, lymph node and splenic white pulp) was much greater than that in the hematopoietic tissues (the bone marrow and splenic red pulp). Based on these evidences, it was reasonably considered that the reticular framework and reticular fiber ensheathed by the cytoplasm of the fibroblastic reticular cells were the most representative common structure in the reticuloendothelial system (RES) and played some important roles in the functions of RES.