ABSTRACT
Left cardiac sympathetic denervation (LCSD) has emerged as an alternative therapy for individuals diagnosed with long QT syndrome (LQTS), a genetic disorder characterized by abnormal electrical activity in the heart and sudden cardiac death (SCD). This review examines the history and rationale behind LCSD in LQTS treatment, as well as the procedure, its efficacy, and indications along with the adverse effects that may be associated with it. LQTS presents with prolonged QT intervals on an electrocardiogram and can manifest as seizures, fainting, and SCD. Beta-blockers are the primary treatment for LQTS but some patients do not respond well to these medications or experience side effects. Additionally, implantable cardioverter-defibrillators (ICDs) are not always effective in preventing arrhythmias and can lead to complications. LCSD might offer an alternative approach by disrupting sympathetic activity in the heart. In humans, LCSD reduces the release of norepinephrine, normalizes the QT interval, and decreases the likelihood of life-threatening heart rhythms. The procedure does not impair heart rate or cardiac function due to the compensatory effects of the right cardiac sympathetic nerves. The surgical procedure for LCSD involves the removal of the lower half of the stellate ganglion and thoracic ganglia. Complete denervation is essential for optimal outcomes, while incomplete procedures are considered unacceptable. Traditional and minimally invasive approaches, such as video-assisted thoracic surgery (VATS), are available, with VATS offering shorter hospital stays and fewer complications. In conclusion, LCSD provides a viable treatment option for individuals with LQTS who do not respond well to beta-blockers or require additional protection beyond medication or ICDs. Further research and clinical experience are needed to enhance its acceptance and implementation in routine practice.
ABSTRACT
Asthma is a common pathology worldwide that occurs due to chronic inflammation of the respiratory airways. Persistent pulmonary inflammation leads to low-grade systemic inflammation, influencing blood vessels and triggering coronary artery disease (CAD) events. This review's objectives include discussing the susceptible population for CAD, the mechanism underlying CAD creation in asthma patients, the characteristics of asthma, and the influence of anti-asthmatic medications on CAD development. Adult-onset asthma is strongly linked to CAD and stroke. Future research may shed light on these disparities. Atherosclerosis and asthma are linked through both intrinsic and extrinsic pathways, with inflammation being the intrinsic pathway and hypoxia and tachyarrhythmia being the extrinsic pathways. The most probable mechanisms for increased coronary vasospastic angina (CVsA) incidence in asthmatic patients are vascular smooth muscle cell hypercontraction and endothelial dysfunction. Studies have shown a dose-response relationship between asthma control and myocardial infarction (MI) risk, with uncontrolled asthma at the highest risk. Impairment of ventilatory function is a distinct risk factor for lethal MI and cardiovascular death (CVD). The use of beta-2-agonists and chronic oral glucocorticoid therapy in severe asthmatics has been linked to increasing the risk for CAD. However, some studies have shown that the risk of MI among patients with active asthma is not related to the use of asthma medications. Further research is needed to determine the involvement of adult asthma features and their treatments in the development of CAD.
ABSTRACT
Hypertension (HTN) is a global health concern due to its increasing prevalence and association with life-threatening complications. An intriguing area of investigation in HTN research is the relationship between HTN and hyperuricemia. In light of this, we conducted a review to summarize the relevant studies exploring the link between elevated serum uric acid (sUA) concentration and new-onset HTN. Through a comprehensive search of PubMed Central, MEDLINE, and PubMed databases, we identified 20 studies that met our inclusion criteria. The research encompassed various study designs, including cohort studies, cross-sectional studies, reviews, and clinical trials. Pathologically, the elevated sUA levels activate the renin-angiotensin system and also cause the formation of urate crystals, triggering inflammation in the kidneys. Additionally, direct effects on the endothelium contribute to inflammation, oxidative stress, nitric oxide depletion, and smooth muscle cell proliferation, ultimately leading to atherosclerosis. These diverse mechanisms collectively play a role in the pathogenesis of HTN. Interestingly, lowering sUA has been shown to reverse early-stage HTN dependent on uric acid. However, this effect is not observed in the uric acid-independent second stage of HTN. Various studies have demonstrated an independent and dose-dependent association between sUA levels and the prevalence of HTN across different populations and genders. The review highlights the potential role of uric acid-lowering drugs, like allopurinol, in the prevention and early-stage management of HTN. However, there is scarce research on the efficacy of other uric acid-lowering agents and combination therapies. We believe our review provides compelling evidence of the association between elevated sUA concentration and new-onset HTN. Identifying and managing hyperuricemia can provide a preventive approach to reducing the burden of HTN and its associated complications.
ABSTRACT
Currently RNA transcripts are being used as male fertility biomarker for many mammalian species, but research work on chicken is at halt because classical RNA isolation methods are not effective for chicken spermatozoa. Hence, attempts have been made to optimize RNA isolation protocol from chicken sperm by using different methods, and to confirm the presence of sperm-specific transcripts of PRM and PLCZ1. Semen samples were centrifuged at low speed for removing debris like uric acid. Further, 1mL diluted semen was gently placed over 40% PureSperm or 45%/90% Percoll, and centrifuged to remove somatic cells and immature diploid spermatocytes. RNA was isolated from sperm by using RNAzol or TRIzol reagent or RNeasy Micro kit with certain modification, and RNA quantity and quality were evaluated. RNA isolated by using RNAzol or RNeasy Micro Kit yielded good quantity and quality of RNA for downstream applications compared to TRIzol. 40% PureSperm was found effective in removing somatic cells. RT-PCR results showed that sperm RNA samples were negative for CD4 and PTPRC. All the sperm RNA samples were positive for PRM and PLCZ1, markers of sperm RNA.
Subject(s)
Chickens/physiology , RNA/isolation & purification , Spermatozoa/physiology , Animals , Antigens, CD/genetics , Antigens, CD/metabolism , Gene Expression Regulation/physiology , Male , Protamines/genetics , Protamines/metabolism , RNA/genetics , RNA/metabolismABSTRACT
1. Ovarian morphology, serum hormone concentrations of 17-ß-estradiol, progesterone, testosterone, tri-iodothyronine (T3), thyroxine (T4) and triacylglycerol (TAG) were investigated at 23 and 26 weeks of age in broiler breeder hens provided with ad libitum access to feed. Progesterone, oestrogen-ß, thyroid-α and -ß receptor mRNAs were also quantified in the infundibulum at the same ages. 2. A large variation in the ovarian morphology was observed at 23 weeks of age including hens with undeveloped ovaries, non-laying hens with post ovulatory follicles (POF) and a predominance of non-laying hens without a POF. 3. Serum concentrations of triglyceride, 17-ß-estradiol and progesterone at 23 weeks of age were lower in hens with an undeveloped ovary compared with other groups of hens, whereas testosterone, triiodothyronine and thyroxin were higher. 4. At 26 weeks of age, the average number of hierarchical yellow follicles in normal layers was 7.64 ± 0·41 whereas in internal layers, the follicular numbers were significantly greater at 8.66 ± 0·53. The higher follicular numbers in internal layers were associated with higher serum triglyceride and progesterone concentrations. 5. Oestrogen receptor-ß and thyroid receptor-ß mRNA was up regulated in the infundibulum of internal layers compared with normal laying hens at 26 weeks of age.
Subject(s)
Chickens/anatomy & histology , Hormones/blood , Ovary/anatomy & histology , Sexual Maturation , Triglycerides/blood , Animals , Chickens/growth & development , Chickens/metabolism , Estradiol/blood , Female , Pituitary Gland, Posterior/metabolism , Progesterone/blood , RNA, Messenger/metabolism , Receptors, Steroid/genetics , Receptors, Steroid/metabolism , Receptors, Thyroid Hormone/genetics , Receptors, Thyroid Hormone/metabolism , Testosterone/blood , Thyroxine/blood , Time Factors , Triiodothyronine/bloodABSTRACT
Activation of the complement component C3 is an important step in the complement cascade, contributing to inflammatory mechanisms. Considerable research on gene-disrupted mycobacterial strains using animal models of tuberculosis infection has reported the roles of some of the mycobacterial genes during tuberculosis infection. The aim of the present study was to assess the pattern of complement activation by the devR gene-disrupted Mycobacterium tuberculosis H37Rv strain and compare with that by its wild-type strain. In vitro complement activation at the level of C3 by the gene-disrupted strain, its complemented strain, and wild-type strain was performed using solid-phase ELISA. It was observed that the ability of devR gene-disrupted M. tuberculosis H37Rv to activate C3 was significantly reduced in comparison to its wild-type strain (P < 0.05). In addition, C3 activation by the complemented devR mutant strain was almost similar to that of the wild strain, which indicated that the reduced ability to activate C3 could potentially be due to the deletion of devR gene. These findings indicate that the gene devR probably aids in complement activation and contributes to the inflammatory processes during tuberculosis infection.
ABSTRACT
Standards of services provided by the EPAUs across the UK vary from one unit to another. The aim of this purposive sampling self-administered survey was to assess these standards against a benchmark set by the Royal College of Obstetricians and Gynaecologists (RCOG). These standards were set out in a report by a RCOG working party (2008). Out of 181 units contacted in this survey, 140 units responded. We looked at the setup of the EPAU, services offered, accessibility and protocols for management of miscarriage and ectopic pregnancy. The survey shows that there is a considerable variation in the management protocols and the quality of services offered by the EPAUs in the UK. Many units do not meet the standards set by the RCOG.
Subject(s)
Health Care Surveys , Prenatal Care/standards , Abortion, Spontaneous/therapy , Clinical Protocols/standards , Female , Humans , Pregnancy , Pregnancy, Ectopic/therapy , Quality of Health Care/standards , Surveys and Questionnaires , United KingdomSubject(s)
Aortitis/pathology , Heart Diseases/pathology , Tuberculosis, Cardiovascular/pathology , Adult , Humans , Male , Monocytes/pathologyABSTRACT
Melatonin (N-acetyl-5-methoxytryptamine), an indole hormone, regulates various biological functions through three different receptor subtypes (Mel-1a, Mel-1b, and Mel-1c). However, the distribution of different melatonin receptor subtypes in chicken reproductive tissues was not known. In the present investigation, the partial sequences of ovarian melatonin receptor subtypes (Mel-1a, Mel-1b, and Mel-1c) were characterized. Further, the expression profile of melatonin receptor subtypes in the granulosa and theca layers of different preovulatory and postovulatory follicles (POF) were studied by semi-quantitative RT-PCR. The expression of all three subtypes of melatonin receptors were observed in the ovary of domestic chicken. Analysis of partial sequences of ovarian melatonin receptors revealed that the melatonin subtypes were identical to the brain receptors. In small white ovary follicles, we observed only the expression of mel-1b receptors, but not mel-1a or mel-1c receptors. In yellow follicles, all the three subtypes of receptors expression were noticed. Interestingly, we observed the expression of mel-1a receptor only in thecal layer, but not in granulosa layer. In contrast, mel-1b and -1c receptors were expressed in both granulosa and thecal layer. During the regression of POF, we observed significant upregulation of melatonin receptors (mel-1a and 1c) expression, that downregulated in the later stages of regression. We assume that the expression of melatonin receptors might have been influenced by the atresia or apoptosis of different follicular layers in POF. Our findings suggest that the differential distribution of melatonin receptor subtypes might have distinct downstream cellular functions in the ovarian tissues.
Subject(s)
Chickens/physiology , Gene Expression Profiling/veterinary , Ovary/metabolism , Receptors, Melatonin/metabolism , Animals , Cloning, Molecular , Female , Gene Expression Regulation/physiology , RNA, Messenger/genetics , RNA, Messenger/metabolism , Receptors, Melatonin/geneticsABSTRACT
1. The effects of injecting threonine in ovo on early growth, some immunological responses and the activity of digestive enzymes of broiler chicks were investigated. Fertile eggs were distributed into 6 groups, each of 60. These were: untreated control, sham control, 10, 20, 30 or 40 mg threonine. Threonine was dissolved in 0.5 ml sterile saline and inoculated into the yolk sac of the 14-d-old embryo through the narrow end of the egg. 2. The ratio of chick to egg weight was 1.6% higher in the group given 30 mg threonine and at 28 d of age chicks receiving threonine were 29 to 79 g heavier than untreated controls. 3. Food conversion ratio until 7 d after hatching was improved in those chicks receiving 10, 20 or 40 mg threonine but there was no significant effect on the activities of amylase, pepsin or trypsin. 4. The humoral response to sheep red blood cells was significantly greater in those groups receiving 10, 20 or 30 mg threonine supplementation than in untreated controls. 5. The response to phytohaemagglutinin-P, a measure of the cell-mediated immune response, was not affected, however. 6. It is concluded that injections of 20 to 30 mg threonine into yolk sac can improve post-hatching growth and humoral responses of broiler chicks.
Subject(s)
Chickens/growth & development , Digestion/drug effects , Ovum/drug effects , Threonine/pharmacology , Animals , Antibody Formation/drug effects , Avian Proteins/metabolism , Chick Embryo , Chickens/immunology , Embryonic Development/drug effects , Immunity, Cellular/drug effects , Pepsin A/metabolism , Trypsin/metabolism , alpha-Amylases/metabolismABSTRACT
This experiment was to investigate the effects of increasing the level of dietary Vitamin E (Vit. E) on cloacal gland size, foam production and semen characteristics of male Japanese quail (Coturnix coturnix Japonica). One hundred and eighty male Japanese quail chicks (day old) were randomly distributed to three dietary treatments for a period of 25 weeks. Each treatment comprised of three replicates each containing 20 chicks. The basal diet contained 15 IU Vit. E/kg and the two experimental diets were supplemented with 150 and 300 IU Vit. E/kg (diets T2 and T3, respectively). DL alpha-tocopherol acetate was used as the source of Vit. E. All chicks were provided feed and water ad libitum. Foam characteristics, in terms of frequency of foam discharge (24h), cloacal gland index and foam weight were significantly higher (P<0.05) in T2 group. Body weight, testes weight (left and right) and plasma testosterone concentrations did not differ significantly. Semen characteristics (semen volume, sperm motility, % live sperm, % hatchability and sperm concentrations) did not differ significantly (P>0.05). Percentages of abnormal and dead spermatozoa were significantly (P<0.05) lower and fertility was higher (P<0.05) in the T2 group. From this study, it can be concluded that moderate supplementation of dietary Vit. E may be beneficial for foam production, cloacal gland and improve the semen characteristics in male Japanese quail.
Subject(s)
Cloaca , Coturnix/physiology , Fertility/drug effects , Semen/physiology , Vitamin E/administration & dosage , Vitamins/administration & dosage , Animals , Cloaca/anatomy & histology , Cloaca/drug effects , Cloaca/physiology , Dose-Response Relationship, Drug , Fertility/physiology , Male , Organ Size , Random Allocation , Semen/cytology , Semen/drug effects , Sperm Count/veterinary , Spermatozoa/abnormalities , Spermatozoa/drug effects , Spermatozoa/physiology , Testis/anatomy & histology , Testis/physiology , Testosterone/bloodABSTRACT
1. In this study we investigated the residues of fluoroquinolone drugs (ciprofloxacin and pefloxacin) in the cloacal gland (a site of foam synthesis) and other tissues such as breast muscle, testes, brain, kidney and plasma. 2. Fifty-four healthy male Japanese quail were selected at random from a flock, maintained under uniform husbandry conditions and divided into three groups, each of 18 birds. Group I (control) received 1 ml vehicle (normal saline 0.9% (w/v) NaCl) daily for 12 d through the intraperitoneal route. Birds of groups II and III received ciprofloxacin and pefloxacin by the same route at the rate of 10 and 12 mg/kg body weight, respectively, every day for a similar period. 3. Birds from each group were killed, at 1, 5 and 10 d after the cessation of treatment, to collect the cloacal gland together with other tissues that were analysed for residual drugs. 4. Cloacal gland retained the maximum drug residues of ciprofloxacin (60%) and pefloxacin (80%) on d 10 compared with that on d 1 after drug withdrawal. The drug residues were found 60 and 80% in ciprofloxacin and pefloxacin groups, respectively, in the cloacal gland tissue even on d 10 after withdrawal of the treatment. 5. In the ciprofloxacin-treated group, all tissues except cloacal gland contained very small amounts of the drug residues on d 10 after treatment ended. In the pefloxacin group the cloacal gland, breast muscle and kidney retained a fairly high amount of drug even on d 10 after treatment ceased. No residues of pefloxacin were detectable in testes and brain throughout. 6. In conclusion, the cloacal gland in Japanese quail acted as the largest sink for the fluoroquinolone drugs. Ciprofloxacin was more widely distributed in different tissues and persisted for a shorter period than pefloxacin.
Subject(s)
Anti-Infective Agents/pharmacokinetics , Ciprofloxacin/pharmacokinetics , Cloaca/metabolism , Coturnix/metabolism , Drug Residues/pharmacokinetics , Fluoroquinolones/pharmacokinetics , Pefloxacin/pharmacokinetics , Animals , Brain/metabolism , Coturnix/blood , Kidney/metabolism , Male , Muscle, Skeletal/metabolism , Testis/metabolism , Time FactorsABSTRACT
Role of nitric oxide (NO) in regulating the reproductive functions at hypothalamo-hypophysealovarian axis in Japanese quail was studied. In first experiment, metabolites of NO, i.e. nitrite and nitrate (NO2 and NO3) were estimated together in hypothalamus, serum and ovarian follicles of good and poor layers. In the second experiment, different NO modulators such as L-arginine (L-Arg), sodium nitroprusside (SNP) and N(G)-nitro-L-arginine methyl ester, HCl (L-NAME) were administered to the birds. In the first experiment, significantly higher (P < 0.01) NO2 and NO3 levels in serum, hypothalamus and largest (F1) ovarian follicles were observed in good layers as compared to poor layers. Higher (P < 0.05) NO2 and NO3 concentration was observed in F1 follicles than smaller follicles (F2) only in good layers. The NO2 and NO3 concentration was significantly reduced (P < 0.05) in post ovulatory follicles (POFs) in comparison to F1 and F2 follicles. In the second experiment, the serum NO2 and NO3 concentrations were higher (P < 0.05) in the SNP, lower (P < 0.05) in the L-Name group and unchanged in the L-Arg treated group in comparison to control group. compared to control, L-Arg and SNP increased (P < 0.05) the hypothalamic NO2 and NO3 concentration where as L-NAME reduced (P < 0.05) these levels. The NO2 and NO3 concentration was increased (P < 0.05) as the follicle size increased and it was significantly reduced (P < 0.05) in POFs. The higher (P < 0.05) follicular NO2 and NO3 concentration was observed in L-Arg group in comparison to control group. Egg production was also found to be higher (P < 0.05) in L-Arg group whereas it was not different (P > 0.05) in SNP and L-NAME treated groups. The yolk weight and yolk to albumin ratio was reduced (P < 0.05) in L-NAME group in comparison to control group. It may be concluded from the present study that NO plays a key role in regulating follicular development, ovulatory mechanisms and egg production in Japanese quail.
Subject(s)
Coturnix/physiology , Nitric Oxide/physiology , Ovarian Follicle/physiology , Oviposition , Ovum/physiology , Animals , Enzyme Inhibitors/pharmacology , Female , Hypothalamus/chemistry , NG-Nitroarginine Methyl Ester/pharmacology , Nitrates/analysis , Nitrates/blood , Nitric Oxide Synthase/antagonists & inhibitors , Nitrites/analysis , Nitrites/blood , Nitroprusside/pharmacology , Ovarian Follicle/chemistryABSTRACT
The gene for histone-like protein (hupB [Rv2986c]) of Mycobacterium tuberculosis has been identified as a singular target which allows differentiation of two closely related mycobacterial species, namely, M. tuberculosis and M. bovis of the MTB complex, by a PCR assay. The N and S primer-generated PCR amplicons differed in M. tuberculosis and M. bovis; these amplicons were determined to be 645 and 618 bp, respectively. This difference was localized to the C-terminal part of the gene by using primers M and S. The C-terminal PCR amplicons of M. tuberculosis and M. bovis were determined to be 318 and 291 bp, respectively. The differences in the C-terminal portion of the gene were confirmed by restriction fragment length polymorphism analysis and sequencing. Sequence analysis indicated that in M. bovis there was a deletion of 27 bp (9 amino acids) in frame after codon 128 in the C-terminal part of the hupB gene. In the present study 104 mycobacterial strains and 11 nonmycobacterial species were analyzed for hupB gene sequences. Of the 104 mycobacterial strains included, 62 belonged to the MTB complex and 42 were non-MTB complex strains and species. Neither the hupB gene-specific primers (N and S) nor the C-terminal primers (M and S) amplify DNA from any other mycobacteria, making the assay suitable for distinguishing members of the MTB complex from other mycobacterial species, as well as for differentiating between members of the MTB complex, namely, M. tuberculosis and M. bovis.
Subject(s)
Genes, Bacterial , Histones/genetics , Mycobacterium bovis/genetics , Mycobacterium tuberculosis/genetics , Polymerase Chain Reaction/methods , Base Sequence , Humans , Molecular Sequence Data , Mycobacterium bovis/isolation & purification , Mycobacterium tuberculosis/isolation & purification , Polymorphism, Restriction Fragment Length , RNA, Ribosomal, 23S/geneticsABSTRACT
A macro and micro assay for the spectrophotometric determination of serum nitrite and nitrate was developed. Nitrite/nitrate in biological samples can be estimated in a single step by this method. The principle of the assay is the reduction of nitrate by copper-cadmium alloy, followed by color development with Griess reagent (sulfanilamide and N-naphthylethylenediamine) in acidic medium. This assay is sensitive to 1 microM nitrate and is suitable for different biological fluids, including sera with a high lipid concentration. The copper-cadmium alloy used in the present method is easy to prepare and can completely reduce nitrate to nitrite in an hour. The present method provides a simple, cost-effective assay for the estimation of stable oxidation products of nitric oxide in biological samples.
Subject(s)
Alloys/chemistry , Cadmium/chemistry , Copper/chemistry , Nitrates/blood , Nitrites/blood , Spectrophotometry, Ultraviolet/methods , Animals , Buffaloes , Cattle , Chickens , Coturnix , Ethylenediamines , Free Radical Scavengers , Goats , Humans , Nitric Oxide/chemistry , Oxidation-Reduction , Rats , Sensitivity and Specificity , Sheep , Sulfanilamides , Time FactorsABSTRACT
Nucleic acid amplification technologies offer great promise for the rapid, sensitive and specific diagnosis of tuberculosis. However, the isolation of inhibitor-free DNA from biological specimens is a bottleneck of the PCR assay. Here we describe a simple method for the isolation of PCR-amplifiable DNA of Mycobacterium tuberculosis from all types of samples of pulmonary and extrapulmonary origin tested. Briefly, it involves concentration of the bacilli by high-speed centrifugation, removal of PCR inhibitors by a wash solution containing guanidinium isothiocyanate and the release of bacterial DNA by heating in the presence of detergents and Chelex-100 resin. The entire process is accomplished within approximately 3 h. The method has been validated on 780 samples of human, bovine and guinea pig origin including sputum, cerebrospinal fluid, pulmonary fluids, pus, fine needle aspirate, tissue, blood and milk.
Subject(s)
Isothiocyanates , Animals , Body Fluids/chemistry , Body Fluids/microbiology , Cattle , DNA, Bacterial/analysis , DNA, Bacterial/isolation & purification , Guinea Pigs , Humans , Isothiocyanates/chemistry , Mycobacterium tuberculosis/genetics , Mycobacterium tuberculosis/isolation & purification , Polymerase Chain Reaction/methods , Polymerase Chain Reaction/standards , Sensitivity and Specificity , Tuberculosis/diagnosis , Tuberculosis/microbiology , Tuberculosis, Bovine , Tuberculosis, PulmonaryABSTRACT
A 37-year-old female underwent heart transplantation for giant cell myocarditis. The patient died within three-and-a-half months of cardiac transplantation. Postmortem specimens from the heart and lung showed multiple necrotizing granulomas with numerous acid-fast bacilli. Polymerase chain reaction done on both the postmortem samples confirmed the presence of atypical mycobacterial infection. This fatal case of atypical mycobacteriosis in a cardiac transplant patient is reported for its rarity.
Subject(s)
Heart Transplantation , Mycobacterium Infections, Nontuberculous , Myocarditis/surgery , Adult , Fatal Outcome , Female , Humans , Lung/pathology , Mycobacterium Infections, Nontuberculous/pathology , Myocardium/pathology , Polymerase Chain ReactionABSTRACT
By subtractive hybridization, we isolated genes, differentially expressed in virulent strain (dev), that are expressed at higher levels in the virulent Mycobacterium tuberculosis H37Rv strain in comparison to its avirulent counterpart, H37Ra, and consequently may be associated with the virulence phenotype of M. tuberculosis. A two-component system, devR-devS, was identified by DNA sequencing of a dev clone. DevR, the predicted gene product of devR, is a response regulator (RR) in the NarL/ UhpA subfamily of two-component systems. The devS gene product displayed homology with histidine protein kinases (HPKs) including UhpB, NarX and NarQ. The devR-devS locus is preceded by gene Rv3134c that encodes a putative alanine-aline- rich protein. This locus was conserved in M. tuberculosis and M. bovis BCG but not in other mycobacteria. A devR -lacZ transcription fusion demonstrated beta-galactosidase activity in M. smegmatis and in M. tuberculosis. The devR and devS genes were cotranscribed and the levels of their transcripts were lower in two isolates of the avirulent H37Ra strain in comparison to the virulent H37Rv strain of M. tuberculosis. The level of DevR protein was also lower in one of the H37Ra strains in comparison to the H37Rv strain. However, in a third isolate of H37Ra, RNA and protein expression was equivalent to that in the H37Rv strain. Electron microscopic immunogold analysis of M. tuberculosis grown in laboratory medium and within human monocytes revealed specific labelling for DevR protein within the bacteria and the phagosomal lumen of infected monocytes. These findings collectively suggest a potential role for devR-devS in the regulation of genetic programmes unique to the tubercle bacillus.
Subject(s)
Genes, Bacterial , Mycobacterium tuberculosis/genetics , Cells, Cultured , Gene Expression Regulation, Bacterial , Molecular Sequence Data , Monocytes/cytology , Monocytes/microbiology , Mycobacterium tuberculosis/cytology , Mycobacterium tuberculosis/pathogenicity , Nucleic Acid Hybridization , Phenotype , Sequence Alignment , Sequence Analysis, DNA , Signal Transduction/genetics , Transcription, Genetic , Two-Hybrid System Techniques , Virulence/geneticsABSTRACT
AIMS: To evaluate the usefulness of the devR based polymerase chain reaction (PCR) in the detection of Mycobacterium tuberculosis in lymph node aspirates and tissues of lymphadenitis and to compare PCR with conventional diagnostic techniques. SUBJECTS AND METHODS: Coded specimens of fine needle aspirates and biopsies from 22 patients with tuberculous lymphadenitis, 14 patients with non-tubercular lymphadenitis, and nine patients with granulomatous lymphadenitis were processed and subjected to analysis by PCR, smear microscopy, M tuberculosis culture, histology, and cytology. RESULTS: Tuberculous lymphadenitis was correctly diagnosed by PCR in 18 patients, by culture in five patients, by histology in 13 patients, and by cytology in seven patients. PCR gave two false positive results in 14 patients with non-tubercular lymphadenitis. The sensitivity of the conventional techniques was significantly higher with biopsies (17 of 22 specimens; 77%) than with fine needle aspirates (nine of 22 specimens; 41%). However, the sensitivity of PCR was not significantly higher with biopsies (68%) in comparison with fine needle aspirates (55%). The sensitivity of either biopsy PCR or fine needle aspirate PCR was not significantly different from that of either histology combined with culture or cytology combined with culture. The overall combined specificity of PCR was 86%. Mycobacterium tuberculosis DNA was detected in six of nine patients with granulomatous lymphadenitis. CONCLUSION: PCR is the most sensitive single technique available to date for the demonstration of M tuberculosis in specimens derived from patients with a clinical suspicion of tuberculous lymphadenitis. The value of PCR lies in its use as an adjunct test in the diagnosis of tuberculous lymphadenitis, particularly in those patients where conventional methods fail. Because fine needle aspiration is not an invasive procedure, it is the procedure of choice, and PCR should be performed initially on these samples. Excisional biopsy histology and PCR should be recommended only for patients in whom fine needle aspirate PCR is negative or when there is discrepancy with the clinical impression.