Increased expression of ER stress, inflammasome activation, and mitochondrial biogenesis-related genes in peripheral blood mononuclear cells in major depressive disorder

A subset of major depressive disorder (MDD) is characterized by immune system dysfunction, but the intracellular origin of these immune changes remains unclear. Here we tested the hypothesis that abnormalities in the endoplasmic reticulum (ER) stress, inflammasome activity and mitochondrial biogenesis contribute to the development of systemic inflammation in MDD. RT-qPCR was used to measure mRNA expression of key organellar genes from peripheral blood mononuclear cells (PBMCs) isolated from 186 MDD and 67 healthy control (HC) subjects. The comparative CT (2-ΔΔCT) method was applied to quantify mRNA expression using GAPDH as the reference gene. After controlling for age, sex, BMI, and medication status using linear regression models, expression of the inflammasome (NLRC4 and NLRP3) and the ER stress (XBP1u, XBP1s, and ATF4) genes was found to be significantly increased in the MDD versus the HC group. After excluding outliers, expression of the inflammasome genes was no longer statistically significant but expression of the ER stress genes (XBP1u, XBP1s, and ATF4) and the mitochondrial biogenesis gene, MFN2, was significantly increased in the MDD group. ASC and MFN2 were positively correlated with serum C-reactive protein concentrations. The altered expression of inflammasome activation, ER stress, and mitochondrial biogenesis pathway components suggest that dysfunction of these organelles may play a role in the pathogenesis of MDD.

Exploring the role of neuronal-enriched extracellular vesicle miR-93 and interoception in major depressive disorder

Major depressive disorder (MDD) is associated with interoceptive processing dysfunctions, but the molecular mechanisms underlying this dysfunction are poorly understood. This study combined brain Neuronal-Enriched Extracellular Vesicle (NEEV) technology and serum markers of inflammation and metabolism with Functional Magnetic Resonance Imaging (fMRI) to identify the contribution of gene regulatory pathways, in particular micro-RNA (miR) 93, to interoceptive dysfunction in MDD. Individuals with MDD (n = 44) and healthy comparisons (HC; n = 35) provided blood samples and completed an interoceptive attention task during fMRI. EVs were separated from plasma using a precipitation method. NEEVs were enriched by magnetic streptavidin bead immunocapture utilizing a neural adhesion marker (CD171) biotinylated antibody. NEEV specificities were confirmed by ow cytometry, western blot, particle size analyzer, and transmission electron microscopy. NEEV small RNAs were purified and sequenced. Results showed that: (1) MDD exhibited lower NEEV miR-93 expression than HC; (2) within MDD but not HC, those individuals with the lowest NEEV miR-93 expression had the highest serum concentrations of interleukin (IL)-1 receptor antagonist, IL-6, tumor necrosis factor, and leptin; and (3) within HC but not MDD, those participants with the highest miR-93 expression showed the strongest bilateral dorsal mid-insula activation. Since miR-93 is regulated by stress and affects epigenetic modulation by chromatin reorganization, these results suggest that healthy individuals but not MDD participants show an adaptive epigenetic regulation of insular function during interoceptive processing. Future investigations will need to delineate how specific internal and external environmental conditions contribute to miR-93 expression in MDD and what molecular mechanisms alter brain responsivity to body-relevant signals.

A Case of Enteropathy Associated T-Cell Lymphoma (EATL) with Aberrant Phenotype, CD8+, CD56+: From Diagnosis to Death

Introduction/Objective

Enteropathy Associated T-Cell Lymphoma (EATL) is a rare and aggressive subtype of primary intestinal T cell lymphoma which occurs in patients with Celiac Disease (CD), most prevalent in the western world with an incidence rate of 0.22-1.9 cases per 100,000. The classic immophenotype of these neoplastic intestinal T cells show loss of CD8 and CD56. The adherence to gluten-free diet, markedly decreases the incidence of this complication.

Methods

The patient’s previous and current biopsies, autopsy and EMR were reviewed. The patient is 66-year female that was diagnosed with Celiac Disease in 2003 after duodenal biopsy showed features suggestive of CD with positive anti-endomysial IgA antibody serology. She presents currently with burning abdominal pain, with subsequent CT scan showing a mass in the small bowel with mid gut rotation and lesions in the lungs, liver and bladder.

Endoscopy showed multiple lesions extending from the hypopharynx to the large bowel, which on biopsy showed CD3+ lymphocytes expanding the lamina propria and infiltrating the crypt epithelium. Given the patient’s clinical history a diagnosis of EATL was made. The patient passed 5 days after diagnosis due to small bowel perforation.

Results

The initial duodenal biopsy showed villous blunting and increased intraepithelial lymphocytes. The biopsies of the gastrointestinal lesions show abnormal infiltrate of pleomorphic, intermediate in size lymphocytes with round to irregular and occasionally cleaved nuclei with pale to clear cytoplasm. These cells infiltrate the crypt epithelium. The immophenotype of these neoplastic cells are positive for CD3, CD7, CD8, CD56, TIA-1 and BF1, while negative for CD4, CD5 and CD30. T cell clonality was also positive. In addition to the above lesions, autopsy revealed involvement of an area of small bowel perforation with full-thickness mucosal wall involvement by the neoplastic cells. In addition, there is widely dissemenated disease involving the lung, liver, bone marrow, spleen, mesenteric lymph nodes, omentum, bladder, ovaries and myometrium (first report of uterine involvement).

Conclusion

CD8 positive EATL may occur in 19-30% of cases, and increases up to 50% in refractory CD. The differential diagnosis of MEITL, which is typically CD8 positive, is important and most be distinguished on the basis of clinical setting in the presence of Celiac Disease.

The Crushing Effects Of Opiate Abuse: Two Cases Illustrating The Morphologic Features Of Acute And Chronic Intravenous Administration Of Crushed Oral Opiates

Introduction/Objective

Drug overdose related deaths in the US have shown a four-fold increase over the past two decades, increasing from 6.1 to 21.7 per 100,000, the increasing majority of which involve synthetic opioid use. With this continuing increase, it is important for pathologists to become aware of unusual gross and microscopic changes related to unconventional modes of drug abuse. A less recognized unconventional method for opiate abusers to ingest these substances exemplified by our two cases is by crushing oral tablets and inhaling or injecting the drug intravenously, subcutaneously or intramuscularly.

Methods

The two cases being presented show morphological features of acute and chronic opiate abuse by autopsy study. Case 1 was a 38-year old female, who underwent spinal fusion surgery 1 month prior, and was found unresponsive at home. Case 2 was a 37-year-old female with a history of Antiphospholipid Antibody Syndrome (APA) and upper limb DVTs who was found unresponsive one day after elective utero-vaginal prolapse surgery.

Results

At autopsy, Case 1 showed extensive embolization of polarizable foreign body material (possible “pill filler”) and fibrin in small and medium sized vessels without inflammatory reaction in the lungs bilaterally. The foreign material was also present in the small vessels of the heart associated with multifocal acute inflammation, hemorrhage, foreign body giant cell reaction and multiple myocardial infarcts (elevated troponin levels clinically). Blood and vitreous fluid were positive for oxycodone. At autopsy, Case 2 showed an extensive angiocentric miliary pattern of granulomatous reaction to polarizable foreign material, consistent with pill filler in the lungs bilaterally. This foreign material was also present within the lumens and walls of pulmonary vessels and in the skin of the legs. Chronic changes of hypertrophic cardiomyopathy, hepatic cirrhosis and congestive splenomegaly were evident. The blood oxycodone levels were ten times the normal limit.

Conclusion

These cases illustrate the importance of recognizing the clinical and morphological features of unorthodox acute and chronic opiate abuse. Lack of familiarity with their differing features can lead to a delay in diagnosis and institution of appropriate timely management and treatment.

Web-Based Graphic Representation of the Life Course of Mental Health: Cross-Sectional Study Across the Spectrum of Mood, Anxiety, Eating, and Substance Use Disorders

BACKGROUND

Although patient history is essential for informing mental health assessment, diagnosis, and prognosis, there is a dearth of standardized instruments measuring time-dependent factors relevant to psychiatric disorders. Previous research has demonstrated the potential utility of graphical representations, termed life charts, for depicting the complexity of the course of mental illness. However, the implementation of these assessments is limited by the exclusive focus on specific mental illnesses (ie, bipolar disorder) and the lack of intuitive graphical interfaces for data collection and visualization.

OBJECTIVE

This study aimed to develop and test the utility of the Tulsa Life Chart (TLC) as a Web-based, structured approach for obtaining and graphically representing historical information on psychosocial and mental health events relevant across a spectrum of psychiatric disorders.

METHODS

The TLC interview was completed at baseline by 499 participants of the Tulsa 1000, a longitudinal study of individuals with depressive, anxiety, substance use, or eating disorders and healthy comparisons (HCs). All data were entered electronically, and a 1-page electronic and interactive graphical representation was developed using the Google Visualization Application Programming Interface. For 8 distinct life epochs (periods of approximately 5-10 years), the TLC assessed the following factors: school attendance, hobbies, jobs, social support, substance use, mental health treatment, family structure changes, negative and positive events, and epoch and event-related mood ratings. We used generalized linear mixed models (GLMMs) to evaluate trajectories of each domain over time and by sex, age, and diagnosis, using case examples and Web-based interactive graphs to visualize data.

RESULTS

GLMM analyses revealed main or interaction effects of epoch and diagnosis for all domains. Epoch by diagnosis interactions were identified for mood ratings and the number of negative-versus-positive events (all P values <.001), with all psychiatric groups reporting worse mood and greater negative-versus-positive events than HCs. These differences were most robust at different epochs, depending on diagnosis. There were also diagnosis and epoch main effects for substance use, mental health treatment received, social support, and hobbies (P<.001). User experience ratings (each on a 1-5 scale) revealed that participants found the TLC pleasant to complete (mean 3.07, SD 1.26) and useful for understanding their mental health (mean 3.07, SD 1.26), and that they were likely to recommend it to others (mean 3.42, SD 0.85).

CONCLUSIONS

The TLC provides a structured, Web-based transdiagnostic assessment of psychosocial history relevant for the diagnosis and treatment of psychiatric disorders. Interactive, 1-page graphical representations of the TLC allow for the efficient communication of historical life information that would be useful for clinicians, patients, and family members.

Real-Time Functional Magnetic Resonance Imaging Amygdala Neurofeedback Changes Positive Information Processing in Major Depressive Disorder

BACKGROUND

In participants with major depressive disorder who are trained to upregulate their amygdalar hemodynamic responses during positive autobiographical memory recall with real-time functional magnetic resonance imaging neurofeedback (rtfMRI-nf) training, depressive symptoms diminish. This study tested whether amygdalar rtfMRI-nf also changes emotional processing of positive and negative stimuli in a variety of behavioral and imaging tasks.

METHODS

Patients with major depressive disorder completed two rtfMRI-nf sessions (18 received amygdalar rtfMRI-nf, 16 received control parietal rtfMRI-nf). One week before and following rtfMRI-nf training, participants performed tasks measuring responses to emotionally valenced stimuli including a backward-masking task, which measures the amygdalar hemodynamic response to emotional faces presented for traditionally subliminal duration and followed by a mask, and the Emotional Test Battery in which reaction times and performance accuracy are measured during tasks involving emotional faces and words.

RESULTS

During the backward-masking task, amygdalar responses increased while viewing masked happy faces but decreased to masked sad faces in the experimental versus control group following rtfMRI-nf. During the Emotional Test Battery, reaction times decreased to identification of positive faces and during self-identification with positive words and vigilance scores increased to positive faces and decreased to negative faces during the faces dot-probe task in the experimental versus control group following rtfMRI-nf.

CONCLUSIONS

rtfMRI-nf training to increase the amygdalar hemodynamic response to positive memories was associated with changes in amygdalar responses to happy and sad faces and improved processing of positive stimuli during performance of the Emotional Test Battery. These results may suggest that amygdalar rtfMRI-nf training alters responses to emotional stimuli in a manner similar to antidepressant pharmacotherapy.

The Effect of Mineralocorticoid and Glucocorticoid Receptor Antagonism on Autobiographical Memory Recall and Amygdala Response to Implicit Emotional Stimuli

BACKGROUND

Acutely elevated cortisol levels in healthy humans impair autobiographical memory recall and alter hemodynamic responses of the amygdala to emotionally valenced stimuli. It is hypothesized that the effects of the cortisol on cognition are influenced by the ratio of mineralocorticoid receptor to glucocorticoid receptor occupation. The current study examined the effects of acutely blocking mineralocorticoid receptors and glucocorticoid receptors separately on 2 processes known to be affected by altering levels of cortisol: the specificity of autobiographical memory recall, and the amygdala hemodynamic response to sad and happy faces.

METHODS

We employed a within-subjects design in which 10 healthy male participants received placebo, the mineralocorticoid receptor antagonist spironolactone (600mg) alone, and the glucocorticoid receptor antagonist mifepristone (600mg) alone in a randomized, counter-balanced order separated by 1-week drug-free periods.

RESULTS

On autobiographical memory testing, mineralocorticoid receptor antagonism impaired, while glucocorticoid receptor antagonism improved, recall relative to placebo, as evinced by changes in the percent of specific memories recalled. During fMRI, the amygdala hemodynamic response to masked sad faces was greater under both mineralocorticoid receptor and glucocorticoid receptor antagonism relative to placebo, while the response to masked happy faces was attenuated only during mineralocorticoid receptor antagonism relative to placebo.

CONCLUSIONS

These data suggest both mineralocorticoid receptor and glucocorticoid receptor antagonism (and potentially any deviation from the normal physiological mineralocorticoid receptor/glucocorticoid receptor ratio achieved under the circadian pattern) enhances amygdala-based processing of sad stimuli and may shift the emotional processing bias away from the normative processing bias and towards the negative valence. In contrast, autobiographical memory was enhanced by conditions of reduced glucocorticoid receptor occupancy.

Second-line drug susceptibility breakpoints for Mycobacterium tuberculosis using the MODS assay

OBJECTIVE

To establish breakpoint concentrations for the fluoroquinolones (moxifloxacin [MFX] and ofloxacin [OFX]) and injectable second-line drugs (amikacin [AMK], kanamycin [KM] and capreomycin [CPM]) using the microscopic observation drug susceptibility (MODS) assay.

SETTING

A multinational study conducted between February 2011 and August 2012 in Peru, India, Moldova and South Africa.

DESIGN

In the first phase, breakpoints for the fluoroquinolones and injectable second-line drugs (n = 58) were determined. In the second phase, MODS second-line drug susceptibility testing (DST) as an indirect test was compared to MGIT™ DST (n = 89). In the third (n = 30) and fourth (n = 156) phases, we determined the reproducibility and concordance of MODS second-line DST directly from sputum.

RESULTS

Breakpoints for MFX (0.5 μg/ml), OFX (1 μg/ml), AMK (2 μg/ml), KM (5 μg/ml) and CPM (2.5 μg/ml) were determined. In all phases, MODS results were highly concordant with MGIT DST. The few discrepancies suggest that the MODS breakpoint concentrations for some drugs may be too low.

CONCLUSION

MODS second-line DST yielded comparable results to MGIT second-line DST, and is thus a promising alternative. Further studies are needed to confirm the accuracy of the drug breakpoints and the reliability of MODS second-line DST as a direct test.

Treatment outcomes of multidrug-resistant tuberculosis patients in Gauteng, South Africa

PURPOSE

Multidrug-resistant tuberculosis (MDR-TB) is associated with lengthy treatment, expensive and potentially toxic regimens, and high rates of treatment failure and death. This study describes the outcomes of 351 MDR-TB patients who started treatment between 2004 and 2007 at the provincial MDR-TB referral hospital in Johannesburg, South Africa, and investigates risk factors associated with death.

METHODS

The study involved the assessment of factors associated with treatment outcomes using a retrospective review of patient records, drug-susceptibility data and spoligotyping of isolates.

RESULTS

Treatment success (completion/cure) was recorded in 158 (48.8 %) patients, while 65 (20 %) died, 93 (28.7 %) defaulted, 8 (2.5 %) failed treatment, 11(3.1 %) were transferred out to other health facilities and 16 (4.6 %) had no recorded final outcome. The proportion of successful treatment increased significantly over time. Univariable and multivariable analysis (P = 0.05) identified the year of MDR-TB diagnosis and spoligotype-defined families as factors associated with treatment outcome. No associations were found between treatment outcome and human immunodeficiency virus (HIV) status, previous TB and additional MDR resistance to streptomycin or ethambutol. Molecular typing of the strains revealed a diverse group of spoligotypes, with Beijing, LAM4 and H3 making up the largest groups.

CONCLUSIONS

This is the first published study to investigate treatment outcomes at this facility and to find a link between genotype and treatment outcome, suggesting that genotype determination could potentially serve as a prognostic factor.

Inflammation and neurological disease-related genes are differentially expressed in depressed patients with mood disorders and correlate with morphometric and functional imaging abnormalities

Depressed patients show evidence of both proinflammatory changes and neurophysiological abnormalities such as increased amygdala reactivity and volumetric decreases of the hippocampus and ventromedial prefrontal cortex (vmPFC). However, very little is known about the relationship between inflammation and neuroimaging abnormalities in mood disorders. A whole genome expression analysis of peripheral blood mononuclear cells yielded 12 protein-coding genes (ADM, APBB3, CD160, CFD, CITED2, CTSZ, IER5, NFKBIZ, NR4A2, NUCKS1, SERTAD1, TNF) that were differentially expressed between 29 unmedicated depressed patients with a mood disorder (8 bipolar disorder, 21 major depressive disorder) and 24 healthy controls (HCs). Several of these genes have been implicated in neurological disorders and/or apoptosis. Ingenuity Pathway Analysis yielded two genes networks, one centered around TNF with NFKβ, TGFβ, and ERK as connecting hubs, and the second network indicating cell cycle and/or kinase signaling anomalies. fMRI scanning was conducted using a backward-masking task in which subjects were presented with emotionally-valenced faces. Compared with HCs, the depressed subjects displayed a greater hemodynamic response in the right amygdala, left hippocampus, and the ventromedial prefrontal cortex to masked sad versus happy faces. The mRNA levels of several genes were significantly correlated with the hemodynamic response of the amygdala, vmPFC and hippocampus to masked sad versus happy faces. Differentially-expressed transcripts were significantly correlated with thickness of the left subgenual ACC, and volume of the hippocampus and caudate. Our results raise the possibility that molecular-level immune dysfunction can be mapped onto macro-level neuroimaging abnormalities, potentially elucidating a mechanism by which inflammation leads to depression.

Loss of Fatty-Acid delta(6) desaturating ability in human mammary epithelial-cells that express an activated C-ha-ras oncogene

The synthesis of essential fatty acids (EFAs) that have been shown to inhibit breast cancer cell growth in vitro and tumor growth in animals requires desaturation at C-6 of linoleic or alpha-linolenic acid. This observation, combined with reports that many tumors and tumor cell lines are deficient in Delta(6) desaturation and/or contain low levels of 6-desaturated EFAs, has led to the suggestion that loss of Delta(6) desaturating ability is relevant to the process of malignant transformation. This study was undertaken in search of direct evidence that malignant transformation of mammary epithelial cells alters EFA metabolism. We used two cell lines derived from the spontaneously immortalized human mammary epithelial cell line MCF-10A and expressing either the c-Ha-ras protooncogene (MCF-10AneoN) or an activated c-Ha-ras oncogene (MCF-10AneoT), and a cell line immortalized by transfection of human mammary epithelial cells with SV40 T antigen. We compared these cell lines in terms of ability to convert EFAs (30 mu M) to other EFAs of the same family. MCF-10AneoT cells lose the ability to perform Delta(6) and Delta(4) desaturations, whereas MCF-10AneoN cells and the SV40 T antigen-transformed cell line do not. No significant changes in growth response to culture with 6-desaturated EFAs were noted for MCF-10AneoT cells compared with MCF-10AneoN and parental MCF-10A cells, suggesting that FA metabolism alone cannot account for the effects of EFAs on the growth of neoplastic and non-neoplastic mammary epithelial cells.

False-positive rifampicin resistance on Xpert® MTB/RIF: case report and clinical implications

The World Health Organization had endorsed Xpert® MTB/RIF (Xpert) as the initial diagnostic for multidrug-resistant tuberculosis (TB) or TB suspects co-infected with the human immunodeficiency virus. We investigated an unexpected case of rifampicin (RMP) resistance on Xpert using repeat Xpert, smear microscopy, MTBDRplus assay, culture, drug susceptibility testing, spoligotyping and rpoB gene sequencing. A false-positive result was most likely, given the wild type rpoB gene sequence and exclusion of both mixed infection and mixture of drug-susceptible and drug-resistant populations. When decentralising Xpert, test performance characteristics need to be understood by health care workers and methods of confirmation of RMP resistance need to be accessible.

The evolving epidemic of drug-resistant tuberculosis among children in Cape Town, South Africa

SETTING

Tygerberg Children's Hospital, Cape Town, South Africa.

OBJECTIVE

To determine the prevalence and trend of drug resistance and human immunodeficiency virus (HIV) co-infection among children with culture-confirmed tuberculosis (TB).

METHOD

Prospective surveillance from March 2007 to February 2009, compared to three previous surveys (1994-1998, 2003-2005, 2005-2007). Drug susceptibility testing (DST) against isoniazid (INH) and rifampicin (RMP) was performed using genotypic and phenotypic testing. If multidrug-resistant TB (MDR-TB) was detected, further DST against ethambutol (EMB) and second-line drugs was performed.

RESULTS

A total of 294 children with a median age of 26 months (range 3 days-13 years) were diagnosed with culture-confirmed TB. DST results were available for 292 (99.3%); 41 (14%) were INH-resistant, including 26 (8.9%) with MDR-TB. Four children (1.4%) had RMP monoresistance. EMB resistance was present in 12/24 (50%) MDR-TB cases tested. Two isolates were resistant to ofloxacin; none had extensively drug-resistant TB. Of those tested, 29% (63/217) were HIV-infected. Any resistance to RMP increased between 1994 and 2009 (P < 0.001), as did RMP monoresistance (P = 0.009) and MDR-TB (P < 0.001). Sensitivity was 87.5% and specificity 100% for genotypic compared to phenotypic testing for INH resistance.

CONCLUSIONS

RMP, and consequently multidrug, resistance is increasing among children with TB in this setting. EMB resistance is common among children with resistance to RMP and INH.

Evaluation of a rapid screening test for rifampicin resistance in re-treatment tuberculosis patients in the Eastern Cape

BACKGROUND AND OBJECTIVES

Patients with multidrug-resistant (MDR) tuberculosis (TB) are at high risk of treatment failure. It is anticipated that early identification of MDR-TB and appropriate treatment will improve patient outcome and disease control. We evaluated the rapid detection of rifampicin resistance in previously treated TB patients, directly from acidfast bacilli (AFB)-positive sputum using a phage-based test, FASTPlaque-Response (Biotec Laboratories Ltd, Ipswich, UK). The ability of rifampicin resistance to predict MDR-TB was also determined.

DESIGN

A prospective study was done comparing performance of the rapid phage test with conventional culture and drug susceptibility testing (DST) in AFB-positive TB patients.

SETTING

Five primary health clinics and one TB referral centre in the Port Elizabeth Metropolitan area, Eastern Cape.

OUTCOME MEASURES

Sensitivity, specificity and overall accuracy of the phage test were determined compared with gold standard culture and DST. Discrepant results were resolved by molecular detection of mutations conferring rifampicin resistance. The proportion of rifampicin-resistant strains that were MDR was also determined.

RESULTS

Previously treated patients were at a high risk of MDRTB (35.7%). Sensitivity, specificity and overall accuracy of FASTPlaque-Response for rifampicin resistance determination were 95.4% (95% confidence interval (CI): 91.0 - 99.8%), 97.2% (95% CI: 94.5 - 99.9%) and 96.5% (95% CI: 94.1 - 98.9%) respectively compared with conventional DST (unresolved), calculated for specimens that had both FASTPlaque-Response and conventional DST results available. FASTPlaque-Response results were available in 2 days instead of 28 - 85 days with conventional DST. However, only 70.6% of FASTPlaque-Response results were interpretable compared with 86.3% of conventional DST results. The majority (95.5%) of rifampicinresistant strains were MDR-TB.

CONCLUSIONS

Rapid detection of rifampicin resistance using FASTPlaque-Response could contribute to improved management of patients at risk of MDR-TB, such as previously treated patients. However, improvement in control of specimen-related contamination is needed to ensure that a higher proportion of FASTPlaque-Response results are interpretable. Where indicated, early modification of therapy could improve patient prognosis and reduce disease transmission.

SLC11A1 (NRAMP1) but not SLC11A2 (NRAMP2) polymorphisms are associated with susceptibility to tuberculosis in a high-incidence community in South Africa

SETTING

Stellenbosch University Faculty of Health Sciences, and metropolitan Cape Town, Western Cape, South Africa.

OBJECTIVE

To investigate whether the reported association between SLC11A1 (also NRAMP1) polymorphisms and susceptibility to tuberculosis (TB) can be confirmed in a different population, and whether polymorphisms in SLC11A2 (also NRAMP2, DCT1, DMT1) are associated with TB.

DESIGN

A case-control study design was used to compare the frequencies of five polymorphisms in SLC11A1 and three in SLC11A2 between a group of bacteriologically confirmed TB patients and healthy community controls.

RESULTS

The 5' (GT)9 allele in the promoter of SLC1A1 was found at significantly higher frequencies among 265 controls than in 224 pulmonary TB (PTB) patients (P = 0.002; OR 0.6; 95% CI 0.43-0.83). Homozygotes for the TGTG deletion (1729+55del4) in the 3'UTR of SLC11A1 were over-represented among PTB patients (P = 0.013; OR 5.19; 95% CI 1.42-18.94). Stepwise logistic regression analysis indicated that the 5' and 3' polymorphisms contribute separate main effects. Tuberculous meningitis patients (n = 22) showed the same allele and genotype frequency as PTB patients. No SLC11A2 polymorphisms tested were associated with TB.

CONCLUSION

The 5' (GT)n allele driving the highest rate of transcription of SLC11A1 appears to be associated with protection against TB in the majority of the populations studied.

DNA fingerprinting and molecular epidemiology of tuberculosis: use and interpretation in an epidemic setting

Tuberculosis (TB) is still a major cause of morbidity and mortality. It is clear that control requires more than simple availability of antibiotics. In order to gain insight into the disease, DNA fingerprinting has been applied to the study of bacterial population structure. This technology has been used to quantitate various components of the disease in a high-incidence community, viz. recent transmission (RT) and reactivation (RA) and to monitor these over time as a tool to quantitate changes in the epidemic. In our high-incidence community, we find unexpectedly high strain diversity, lower than predicted RT, and that reactivation disease dominates. This technology can be used to examine and challenge traditional dogmas. Quantitative measure of RT varies over time, using a two-year sliding window for estimation as a useful period. The results show that the "epidemic" consists of subepidemics characterized by strain families that wax and wane in the community of TB patients. The technology is shown to be a useful and quantitative tool to assess disease status and can therefore be used to monitor intervention strategies and refine and monitor results of new control measures.

Polymerase chain reaction in the diagnosis of urinary tract tuberculosis

The polymerase chain reaction (PCR) is a technique that can be used to amplify a specific DNA genomic sequence, whereby the presence of an extremely small number of bacteria can be detected. The high sensitivity of PCR is particularly useful in paucibacillary situations such as non-pulmonary tuberculosis (TB). The aims of the present study were to establish a PCR assay for the rapid detection of Mycobacterium tuberculosis (MTb) in urine, to compare the sensitivity of PCR with routine culture technique (Bactec) and to determine the optimal type of urine specimen for PCR detection of MTb. In the first phase of the study, a total of 92 urine specimens were collected from 83 patients with suspected urinary tract TB. Two urine specimens in 2 patients were positive for TB by both PCR and Bactec, while 90 specimens from 81 patients were negative by both methods. Inhibition of PCR was present in nine urine specimens (10%). In the second phase of the study, a further seven patients were selected for intensive investigation to determine the optimal urine sampling for PCR detection of MTb. The conclusions of the study are that PCR can provide much faster confirmation of urinary TB (within 24-48 h) than Bactec urine culture (which may take several weeks). About 10% of urine specimens could not be evaluated by PCR due to the presence of inhibitory substances of unknown nature. MTb organisms were found to be excreted intermittently in the urine of infected patients, and single specimens were more likely to be false negative than a 24-h sample. The best method appeared to be the concentration of a large volume of urine, for instance 11 concentrated to 2 ml.

Erythema induratum of Bazin. A clinicopathological study of 20 cases and detection of Mycobacterium tuberculosis DNA in skin lesions by polymerase chain reaction

Erythema induratum of Bazin (EIB) is a chronic, recurring panniculitis that is found predominantly on the legs of women with tuberculin hypersensitivity. A causal relationship between EIB and Mycobacterium tuberculosis remains elusive because of the absence of demonstrable organisms in skin lesions. We reviewed the clinicopathological features of 20 patients (all women) with positive Mantoux tests (1:10,000 dilution) and characteristic skin lesions of EIB that cleared up with combined antituberculous treatment. Histological examination of skin lesions confirmed panniculitis with varying combinations of granulomatous inflammation, primary vasculitis, and necrosis. Sections from 20 formalin-fixed, paraffin-embedded skin biopsies obtained from the 20 patients were submitted for polymerase chain reaction (PCR) using oligonucleotide primers for the detection of a 123-bp DNA fragment specific for the M. tuberculosis complex. M. tuberculosis DNA was identified in five of the 20 biopsies. Meticulous care was taken to prevent contamination as a source of false-positive results. Mycobacterial DNA was absent in all negative controls and in normal skin biopsies from purified protein derivative-positive patients with and without EIB. These results provide direct evidence that mycobacterial components are present in EIB lesions and strongly suggest that M. tuberculosis is involved in the pathogenesis of EIB.

The detection of Mycobacterium tuberculosis in bone marrow aspirate using the polymerase chain reaction

SETTING

Tygerberg Hospital, South Africa.

OBJECTIVE

Bone marrow aspirate and biopsy were obtained from 37 patients who were in-patients at the Tygerberg hospital. The specificity and sensitivity of the polymerase chain reaction (PCR) in the detection of Mycobacterium tuberculosis in bone marrow aspirate was evaluated.

DESIGN

The PCR was compared to standard culture as well as to clinical and bone marrow biopsy data in 24 patients with suspected tuberculosis (TB).

RESULTS

12 of the 24 patients eventually had definite or probable TB and in these 12 patients the detection incidence was 42% for PCR and 25% for culture.

CONCLUSION

This study confirms that it is possible to use PCR to detect M. tuberculosis in bone marrow aspirate material and that this technique is more sensitive than culture methods. The PCR technique has the added advantage of being a rapid test yielding results within 2 days of sampling. Overall sensitivity for the detection of M. tuberculosis in bone marrow aspirate may be improved to 58% [corrected] by using both culture and PCR techniques.

Incidence of heat-labile enterotoxin-producing Escherichia coli detected by means of polymerase chain reaction amplification

Diarrhoea can be caused by many different organisms, some of which are notoriously difficult to identify. One of these is enterotoxin-producing Escherichia coli. Recently a new diagnostic technique that uses polymerase chain reaction DNA amplification was developed for detection of the 'A' subunit of the labile enterotoxin-producing E. coli gene. This technique was used to evaluate the incidence of heat-labile (LT+) enterotoxin-producing E. coli in the causation of diarrhoea. The results from this study showed that LT+ E. coli is a cause of diarrhoea in the western Cape and that 5.3% of non-diagnosed diarrhoea patients in Tygerberg Hospital were infected with this pathogen. This represented less than 1% of the total number of cases of diarrhoea investigated in this hospital. The peak coincides with the wetter months in this locality and the infection rate is lower than that reported in most other countries. Given the low incidence of occurrence of this organism we do not recommend routine implementation of the diagnostic procedure. However, this test may be useful at times, e.g. to ascertain the source of a diarrhoea epidemic.

Laboratory experience and guidelines for avoiding false positive polymerase chain reaction results

Despite the widespread use of polymerase chain reaction (PCR) for diagnosis of infectious diseases, the technology has not been generally introduced into routine diagnostic laboratories. One of the most serious problems which has influenced the acceptance of this technology is the occurrence of false positive PCR results. This study describes the experience, in a hospital laboratory setting, of using PCR for the diagnosis of heat-labile enterotoxin-producing E. coli, M. tuberculosis, M. paratuberculosis and human papillomavirus. Results indicate that a build-up of amplicons, generated during the amplification process in the laboratory, is the main source of PCR-contamination. Protocols are described that include both physical and chemical procedures to prevent contamination. The use of photo-induced psoralen is recommended for those laboratories already involved in PCR work where amplicons are likely to be present. An enzymatic system (uracil-N-glycosylase) was evaluated and is recommended for workers intending to start diagnostic PCR. Attention was given to simple control measures which are easily implemented in a routine diagnostic laboratory. Protocols such as these are likely to have a major impact on the introduction of PCR-based methods into routine laboratories.

Papulonecrotic tuberculid. Identification of Mycobacterium tuberculosis DNA by polymerase chain reaction

Sections from 22 formalin-fixed, paraffin-embedded skin biopsies from 12 patients with papulonecrotic tuberculid (PNT) were examined for the presence of Mycobacterium tuberculosis DNA with use of the polymerase chain reaction. All patients had a positive tuberculin skin test and a compatible clinical picture and responded to antituberculous therapy. Histological examination showed the typical morphology of PNT lesions with dermal necrosis surrounded by an ill-formed granulomatous infiltrate. Mycobacterial DNA was detected in 11 of the 22 biopsies. None of the negative controls showed positive DNA identification by amplification. Great care was taken in avoiding false-positive results due to contamination. After reviewing the literature, we believe this is the first time that PNT lesions have been investigated by PCR for the presence of mycobacterial DNA. These findings provide direct proof that mycobacterial products are present in PNT lesions and support the theory that this organism is in some way responsible for the development of PNT.

Purification of sputum samples through sucrose improves detection of Mycobacterium tuberculosis by polymerase chain reaction

A method is described for the routine preparation of sputum samples for detection of Mycobacterium tuberculosis by using polymerase chain reaction amplification. Liquefaction of sputum samples with NaOH and subsequent removal of inhibitors of the polymerase reaction with a 50% sucrose centrifugation step (5 min) in a desktop centrifuge allow direct amplification of a 123-bp repetitive region of the M. tuberculosis genome. We have evaluated the sensitivity and specificity of the sucrose method with 155 sputum specimens from patients suspected of having tuberculosis and from normal healthy volunteers. This method, in our opinion, is reproducible, sensitive, and reliable. Multiple samples can be handled simultaneously, and results can be obtained in one working day.

The use of the polymerase chain reaction test in the diagnosis of tuberculosis

Current techniques for laboratory diagnosis of tuberculosis have some serious limitations. These include the high cost and time required for the current assays. The development of a rapid, sensitive, specific and low-cost assay is therefore of considerable importance. We report here the development and laboratory testing of a polymerase chain reaction DNA-based diagnostic test for the presence of Mycobacterium tuberculosis in sputum. The assay shows a high level of sensitivity and specificity and requires considerably less capital, consumables and time inputs than existing laboratory tests. We believe this technology is ready for large-scale evaluation and use, particularly in hospital-based laboratories.

No evidence for point mutations in codons 12, 13, and 61 of the ras gene in a high-incidence area for esophageal and gastric cancers

The molecular mechanisms underlying the induction of esophageal and gastric cancer are not yet understood. It is possible that different etiological factors from geographically distinct areas play a role in the onset of these cancers. Twenty-seven primary esophageal and 11 gastric cancers originating from the high-incidence areas of South Africa were analyzed for the presence of ras protooncogene mutations. We found no evidence for mutations in codons 12, 13, or 61 or the H-ras, K-ras, and N-ras genes in these primary cancers. Our results indicate that etiological factors such as fungal contamination of basic foodstuffs in a high-incidence area for these cancers do not play a role in the activation of ras genes and that mutations in these genes are not directly involved in the development of primary esophageal and gastric cancers in the South African population.

Estradiol induction of accelerated energy metabolism in prepuberal rat uteri in vitro: mRNA hybridization and [13C]NMR studies

In vitro treatment with 30 nM 17 beta-estradiol stimulated the induction of mRNA for the brain type isozyme of creatine kinase BB (CKBB) and stimulated glucose metabolism in perifused uteri from 27-29-day-old rats. The perifusion conditions maintained the normal NMR spectrum of high energy phosphates for at least 24 h. This technique permitted the demonstration that perifused rat uteri stimulated by 17 beta-estradiol show increased mRNA for creatine kinase BB, 1 h after estrogen addition. The time-course of increase, measured by Northern blot hybridization, parallels that seen in mRNA extracted from uteri after in vivo induction by i.p. injection of 5 micrograms 17 beta-estradiol; the maximal increase is seen at 2-4 h. Experiments utilizing actinomycin D (4 micrograms/ml) for inhibition of RNA synthesis showed that CKB mRNA from both untreated and estradiol stimulated uteri had a similar half-life, of approximately 2 h, indicating that CKB mRNA is transcriptionally regulated. In the same system, the rate of glycolysis was measured by NMR spectroscopy using [1-13C]glucose. Following in vitro stimulation with 30 nM estradiol, glycolysis increased within 3 h, in parallel to increases previously found in uteri from in vivo stimulated rats.

Mitochondrial phospholipid composition and microviscosity in myocardial ischaemia

Normothermic ischaemic arrest of the isolated perfused rat heart causes profound changes in mitochondrial ultrastructure. Since the mitochondrial membranes contain a high percentage of phospholipids, an evaluation of the effect of different periods of ischaemia on mitochondrial phospholipid content and fatty acid composition was made. The results showed that ischaemia had no effect on the content of the different phospholipid classes and no correlation was observed between ultrastructural changes and mitochondrial phospholipid content. However, the phospholipid fatty acid composition of several phospholipids showed marked changes. For example, with lysophosphatidylcholine a progressive increase in the percentage saturated fatty acids was observed with increasing periods of ischaemia, while a reduction occurred in lysophosphatidylethanolamine. To determine whether the ischaemia-induced changes in mitochondrial phospholipid fatty acid composition had an effect on the physical properties of the membrane, the microviscosity of mitochondrial preparations was studied, using the lipophilic probe, 1,6-diphenyl-1,3,5-hexatrine. Mitochondria isolated from ischaemic hearts showed a progressive increase in fluorescence polarization with longer periods of ischaemia, indicating an overall increase in microviscosity. This phenomenon may be responsible for the increased mitochondrial fragility which is characteristic of ischaemic damage.

Physiological and biochemical measurements during a 4-day surf-ski marathon

We studied competitors in the 1983 Texan Challenge surf-ski paddle marathon to determine the effects of 4 days prolonged paddling on sweat rates, rectal temperatures, renal function, serum glucose, free fatty acid, porphyrin and C-reactive protein levels and serum creatine kinase activity. Sweat rates during the race varied from 0.5 to 1.0 l/h, and peak rectal temperatures did not exceed 38 degrees C, even in the most dehydrated subjects. Renal function was unchanged during the race. Plasma renin activity remained low during the race but C-reactive protein levels and serum creatine kinase activity were elevated. Seventy per cent of the subjects had immediate post-exercise blood glucose levels below 3.9 mmol/l after the 1st and 4th days, and 27% had values below 3.0 mmol/l, one competitor requiring intravenous glucose therapy on the beach. Surf-ski paddling is therefore associated with low sweat rates, low levels of dehydration, low body temperature and unchanged renal function. The low post-exercise blood glucose levels indicate that competitors must eat high-carbohydrate diets for the duration of the event and must either eat carbohydrate-containing foods or drink concentrated carbohydrate solutions while paddling.

Myocardial tissue free fatty acids

Myocardial ischaemia, whether produced by coronary artery ligation or by hypoxic low-flow perfusion of the isolated rat heart, has been shown to be associated with a significant depression in mitochondrial function, as well as an increase in tissue free fatty acid (FFA) levels. Although the effects of FFA on mitochondrial oxidative phosphorylation function in vitro are well established, it has not yet been shown that increased tissue FFA levels are causing the depression in mitochondrial function in ischaemia. Using the isolated perfused rat heart, several experiments were performed to gain more information regarding (i) the validity of the Dole FFA extraction technique; (ii) controlling factors; (iii) the relationship between tissue FFA and mitochondrial function and (iv) sources of tissue FFA in ischaemia. Significant elevation of tissue FFA was achieved by perfusion with (i) substrate-free Ringer and (ii) phosphatidylcholine. Elevation of tissue FFA obtained by perfusing with long-chain fatty acids was due to extracellular accumulation. Reduction of tissue FFA levels was observed by perfusing with (i) albumin, (ii) glucose, insulin and propranolol. Our results also suggest that lysosomal involvement could cause the increase in tissue FFA levels in myocardial ischaemia.

The effect of intravenous amino acids on plasma amino acid concentration during total parenteral nutrition in infants with necrotizing enterocolitis

Plasma aminograms of infants receiving total parenteral nutrition as part of the treatment for necrotizing enterocolitis were studied. Their ages varied from 2 to 60 days and their mean birth mass was 1 621 g (range 760-2 550 g). The intravenous administration of amino acids produced changes in plasma amino acid levels corresponding to the concentration of individual amino acid levels in the solution employed: higher levels of amino acids in the infusate produced increased plasma levels, whereas low plasma levels were obtained for amino acids not present or present in small amounts according to the solution used. The infants did not appear to suffer in any way, but the long-term effects still have to be evaluated. Pending further knowledge in this regard it is suggested that plasma amino acid levels should be maintained as near to normal values as possible. This could probably be achieved by the use of amino acid solutions specially formulated according to the amino acid profile of breast milk or the plasma amino acid profile of normal infants.