Antibacterial efficacy of Lawsonia inermis (Henna) against the predominant endodontic pathogen (Enterococcus faecalis)-An in vitro antimicrobial assay

Introduction and Aim: The prospect of a successful root canal therapy relies on three main factors which includes proper instrumentation, disinfection and obturation of root canal. The goal of the present study is to analyse the anti-microbial efficacy of henna (Lawsonia inermis) against the major endodontic pathogen, Enterococcus faecalis.   Materials and Methods: In this study, the antibacterial efficacy of Lawsonia inermis is investigated against Enterococcs feacalis using the method of agar disc diffusion. Extracts of L. inermis were prepared by using methanol as an extraction solvent, whereas DMSO (Dimethyl sulfoxide) and water were used as dissolution solvents. The diluted henna sample was used as the test sample, while positive control used was chlorhexidine gluconate solution and the negative control used was saline. The bacteria were cultured, and the samples were placed to measure the zone of inhibition.   Results: Extracts of L. inermis displayed noteworthy antimicrobial activity against E. fecalis. The zone of inhibition of henna against E. fecalis was found to be 11mm whereas the positive control had 14mm.   Conclusion: In conclusion, the henna extracts had shown acceptable antimicrobial efficacy and thus this study provides the scientific reason for the use of L. inermis in dentistry.

Trans-radial approach versus trans-femoral approach in patients with acute coronary syndrome undergoing percutaneous coronary intervention: An updated meta-analysis of randomized controlled trials

Introduction

Trans-radial approach (TRA) is recommended over trans-femoral approach (TFA) in patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI). We intended to study the effect of access on all-cause mortality.

Methods and results

We searched PubMed and EMBASE for randomized studies on patients with ACS undergoing PCI. The primary outcome was all-cause mortality at 30-days. The secondary outcomes included in-hospital mortality, major adverse cardiac or cerebrovascular event (MACE) as defined by the study, net adverse clinical event (NACE), non-fatal myocardial infarction, non-fatal stroke, stent thrombosis, study-defined major bleeding, and minor bleeding, vascular complications, hematoma, pseudoaneurysm, non-access site bleeding, need for transfusion, access site cross-over, contrast volume, procedure duration, and hospital stay duration. We studied 20,122 ACS patients, including 10,037 and 10,085 patients undergoing trans-radial and trans-femoral approaches, respectively. We found mortality benefit in patients with ACS for the trans-radial approach [(1.7% vs. 2.3%; RR: 0.75; 95% CI: 0.62–0.91; P = 0.004; I2 = 0%). Out of 10,465 patients with STEMI, 5,189 patients had TRA and 5,276 had TFA procedures. A similar benefit was observed in patients with STEMI alone [(2.3% vs. 3.3%; RR: 0.71; 95% CI: 0.56–0.90; P = 0.004; I2 = 0%). We observed reduced MACE, NACE, major bleeding, vascular complications, and pseudoaneurysms. No difference in re-infarction, stroke, and serious bleeding requiring blood transfusions were noted. We noticed a small decrease in contrast volume(ml) {mean difference (95% CI): −4.6 [−8.5 to −0.7]}, small but significantly increase in procedural time {mean difference (95% CI) 1.2 [0.1 to 2.3]}and fluoroscopy time {mean difference (95% CI) 0.8 [0.3 to1.4] min} in the trans-radial group.

Conclusion

TRA has significantly reduced 30-day all-cause mortality among patients undergoing PCI for ACS. TRA should be the preferred vascular access in patients with ACS.

Prevalence of Dental Caries among Different Socioeconomic Status and their Treatment Needs among 5-15-year-old School-going Children in Maduravoyal Area, Chennai

Dental cariology is a discipline with history as long as that of human civilization. It has seen numerous growth and decline phases from the epidemiological perspective. Nevertheless, despite huge amounts of funds being allotted by various international agencies to estimate the prevalence and assess the treatment needs, there always exists a gap between collected data and actual scenarios due to the in-availability of feasible approaches to include all people as samples and assess the statistics, especially the rural population of developing countries. To solve this issue, investigators from various geographic denominations should come forward to present the situation in their dominion. This paper is a report on the prevalence of dental caries in school-going children aged 5-15 years, belonging to various socioeconomic strata. These results have testified to the positive correlation between increased westernization and the prevalence of dental caries. It is also seen that lower economic strata have more predilection for a healthier diet and resultant low prevalence in dental caries. Thus, this study has thrown valuable light on epidemiological aspects of dental caries in Maduravoyal, Chennai-based rural population, which can be used for various planning activities. How to cite this article: Amudha S, Moses J, Vijayakumar M, e t al. Prevalence of Dental Caries among Different Socioeconomic Status and their Treatment Needs among 5-15-year-old School-going Children in Maduravoyal Area, Chennai. Int J Clin Pediatr Dent 2021;14(3):403-411.

Topical anesthesia for stainless steel crown tooth preparation in primary molars: a pilot study

Background

Placement of full-coverage restorations such as stainless steel crowns (SSCs) for pulpectomy treated primary molars is essential for successful outcomes. The tooth preparation process for SSCs can cause discomfort to gingival tissues since the crown should be seated 1 mm subgingivally. The purpose of this prospective trial was to compare the effectiveness of subgingival and transmucosal application of topical anesthetics on dental pain during SSC tooth preparation among 6- to 8-year-old children.

Methods

A consecutive sample of 27 children, aged 6-8 years, who required an SSC after pulp therapy in primary molars were randomly divided into three groups. Group A received infiltration anesthesia before tooth preparation for SSC placement, whereas in Group B and C, only topical anesthesia was applied subgingivally and transmucosally. Wong-Bakers Faces pain rating scale (WBFPS) scores were recorded after tooth preparation. Faces, Legs, Activity, Cry and Consolability (FLACC) scores were evaluated by two blinded and calibrated investigators through video recordings of the patient during tooth preparation. Data were tabulated, and inter-group comparisons were performed using the Kruskal-Wallis and analysis of variance tests.

Results

Out of the 27 participants, 48% were boys and 52% were girls, with an overall mean age of 6.83 years. Group A showed the least pain scores according to both the scales, followed by Group B and Group C. The pain intensity was statistically significant on both the pain scales with P = 0.003 for FLACC and P < 0.001 for WBFPS.

Conclusion

Subgingival application of topical anesthesia reduced pain to a certain extent but not as effectively as infiltration anesthesia during SSC tooth preparation in primary molars. Transmucosal application of topical anesthesia did not reduce discomfort when compared to the other two interventions.

Microleakage patterns of glass ionomer cement at cement-band and cement-enamel interfaces in primary teeth

Context

In-vitro studies of microleakage are an initial screening method to assess the maximum theoretical loss of sealing ability in-vivo.

Aims

Our objective was to determine and compare microleakage patterns of conventional glass ionomer cement (GIC) and resin-modified GIC (RMGIC) for band cementation.

Methods

Forty caries-free second primary molars were randomly divided into two groups of 20 teeth each. Preformed molar bands in the two groups were cemented to enamel with one of two types of cement: Conventional GIC (Fuji I, GC Corporation; Tokyo, Japan) and RMGIC (Fuji Plus, GC Corporation; Tokyo, Japan). A dye penetration method was used for microleakage evaluation. Microleakage was determined by a stereomicroscope for the cement-band and cement-enamel interfaces.

Statistical Analysis Used

Statistical analysis was performed with Kruskal-Wallis and Mann-Whitney U tests.

Results

The mean microleakage value for conventional GIC (Fuji I) at cement-band and cement-enamel interfaces was 2.41 mm and 2.15 mm, respectively. The mean microleakage value for RMGIC (Fuji Plus) at cement-band and cement-enamel interfaces was 0.44 mm and 0.46 mm, respectively. Compared to conventional GIC, RMGIC showed less microleakage at both cement-band and cement-enamel interfaces. P < 0.001 and it was statistically highly significant.

Conclusions

Bands cemented with RMGIC had significantly less microleakage between the cement-band and cement-enamel interfaces than conventional GIC.

Design and Fabrication of Graphene Reinforced Polymer Conductive Patch-Based Inset Fed Microstrip Antenna

This work explores the design and fabrication of graphene reinforced polyvinylidene fluoride (PVDF) patch-based microstrip antenna. Primarily, antenna was designed at 6[Formula: see text]GHz frequency and simulation results were obtained using Ansoft HFSS tool. Later fabrication of antenna was carried out with graphene–PVDF films as conducting patch deposited on bakelite substrate and copper as ground plane. Graphene–PVDF films were prepared using solvent casting process. The radiation efficiency of fabricated microstrip patch antenna was 48% entailing it to be adapted as a practically functional antenna. Both simulated and the practical results were compared and analyzed.

Nondestructive evaluation of graphene-based strain sensor using Raman analysis and Raman mapping

The objective of this work is to use techniques such as Raman analysis and Raman mapping to confirm that graphene-based polyvinylidene fluoride (PVDF) composites can be used in strain sensing industrial applications. The Id/Ig ratio is used to predict the defect level of unstrained graphene-PVDF films with respect to strained graphene-PVDF films. By analyzing the intensity variations of band in the spectra, the defect level present in strained graphene-PVDF films compared with that of unstrained graphene-PVDF films can be predicted. Area mapping is also conducted to correlate the defect variation between unstrained and strained graphene-PVDF films. Raman results were compared with defect level and in turn with induced strain. As expected, results are in concurrence with one another, thereby providing complementary and confirmatory analysis of the results to measure strain.

Lentivirus pre-packed with Cas9 protein for safer gene editing

The CRISPR/Cas9 system provides an easy way to edit specific site/s in the genome and thus offers tremendous opportunity for human gene therapy for a wide range of diseases. However, one major concern is off-target effects, particularly with long-term expression of Cas9 nuclease when traditional expression methods such as via plasmid/viral vectors are used. To overcome this limitation, we pre-packaged Cas9 protein (Cas9P LV) in lentiviral particles for transient exposure and showed its effectiveness for gene disruption in cells, including primary T cells expressing specific single guide RNAs (sgRNAs). We then constructed an 'all in one virus' to express sgRNAs in association with pre-packaged Cas9 protein (sgRNA/Cas9P LV). We successfully edited CCR5 in TZM-bl cells by this approach. Using an sgRNA-targeting HIV long terminal repeat, we also were able to disrupt HIV provirus in the J-LAT model of viral latency. Moreover, we also found that pre-packaging Cas9 protein in LV particle reduced off-target editing of chromosome 4:-29134166 locus by CCR5 sgRNA, compared with continued expression from the vector. These results show that sgRNA/Cas9P LV can be used as a safer approach for human gene therapy applications.

Enhancement of seed germination in stored seeds using different pre-sowing treatments in Bauhinia purpurea L

Bauhinia purpurea L. is one of the important avenue tree species used in garden, road side plantations and other places. Fresh seed produce good germination upto 75 to 100 per cent. Seeds of this species stored for five months produced less germination (38.00 %) and it could be due to seed dormancy. Hence, the present study was carried out to evaluate different seed treatments to enhance seed germination in stored seeds of B. purpurea. Treatment like soaking seeds in hot water for 2 min to 5 min followed by overnight soaking in normal water resultedin highest germination of about 59.00 per cent over control (40.00%). Significant variation for germination parameters such as mean daily germination, germination rate index and germination value as well as early seedling vigour was recorded among different pre-sowing treatments in stored seeds.

A statistical model for the ultrasonic backscattered echo from tissue containing microcalcifications

Microcalcifications, generally seen in B-mode breast images as bright spots, often point to the presence of malignancies. Currently, statistical models to describe the signal strengths from tissue containing microcalcifications rely on the Rician or Nakagami densities. Because the Nakagami density requires the existence of randomly located scatterers with random cross sections, microcalcifications manifesting as isolated strong scatterers in the scattering volume makes it less suitable. Additionally, the absence of any regularly spaced scatterers also makes the Rician density less suitable. In this work, it is proposed that a 3-parameter McKay density with heavier tails than the Nakagami density, and hence more severe intensity fluctuations (speckle), might be a better fit to describe echo from tissue containing microcalcifications. This density is developed using a physical description of scattering and its characteristics are explored through random number simulation. Results demonstrate that the McKay densities have higher levels of speckle quantified through the speckle factor than the corresponding gamma densities (Nakagami for the envelope). Some preliminary analysis of tissue-mimicking phantoms modified to include microcalcification-like regions shows that higher speckle factors (seen with the McKay density) can be used to isolate and display microcalcifications. It is expected that this novel approach based on the McKay density will lead to newer and simpler means to detect and identify microcalcifications in ultrasonic B-scans.

Comparison of the push-out shear bond strength of four types of glass ionomers when used to bond amalgam: An in vitro study

Background:

Dental amalgam is the primary direct posterior restorative material used worldwide, but it have certain shortcomings due to the lack of adhesiveness to the cavity. The introduction of the concept of bonded amalgam helped improve the use of amalgam as a restorative material.

Aim:

Evaluation of the comparative push-out shear bond strength of four types of conventional glass ionomers used to bond amalgam to tooth in simulated class I situations.

Materials and Methods:

Four chemical cure glass ionomers are used: GC Fuji I, GC Fuji II, GC Fuji III and GC Fuji VII, and are compared with unbonded amalgam. The push-out bond strength was tested using the Instron Universal Testing Machine at a crosshead speed of 0.5 mm/min.

Statistical Analysis:

One-way ANOVA and post hoc Bonferroni tests were used to analyze the data.

Results:

The results showed that the use of glass ionomer to bond amalgam resulted in an increase in the bond strength of amalgam. The Type VII glass ionomer showed the highest bond strength in comparison with the other glass ionomers.

Conclusions:

Conventional glass ionomer bonds to amalgam and shows a beneficial increase in the bond strength of the restoration in comparison with unbonded amalgam.

Effect of 10% sodium ascorbate on the calcium: Phosphorus ratio of enamel bleached with 35% hydrogen peroxide: an in vitro quantitative energy-dispersive X-ray analysis

Objectives:

The study assessed quantitatively the calcium and phosphorous loss from the enamel surface following bleaching with 35% hydrogen peroxide and reversal with 10% sodium ascorbate using energy-dispersive X-ray analysis (EDAX).

Materials and Methods:

Eight non-carious, freshly extracted human permanent maxillary central incisors without any visible defects were used. Each specimen was bleached with 35% hydrogen peroxide activated by light and reversed with sodium ascorbate antioxidant gel. The calcium and phosphorous content in weight percent of sound, bleached and reversed enamel was acquired using EDAX. The Ca/P ratio was calculated from the obtained data. One-way ANOVA followed by Post Hoc Tukey test was used for comparing the Ca/P ratio of sound, bleached and reversed enamel.

Results:

All the samples subjected to bleaching using 35% hydrogen peroxide showed a statistically significant decrease in the Ca/P ratio as compared with samples in which no bleaching procedure was performed (P-value < 0.01). The striking finding was that there was a significant increase in the Ca/P ratio on application of sodium ascorbate antioxidant gel when compared with the bleached enamel (P-value < 0.01).

Conclusion:

The authors concluded that 35% hydrogen peroxide causes a significant decrease in the Ca/P ratio. This decrease in the Ca/P ratio can be restored by the application of 10% sodium ascorbate antioxidant gel.

Shear bond strengths of two dentin bonding agents with two desensitizers: An in vitro study

AIM

The aim of this in vitro study was to compare the shear bond strengths of two different dentin bonding agents with two different desensitizers.

MATERIALS AND METHODS

Eighty molars were taken which were ground to expose the dentin. The teeth were divided into two major groups. Each major group was subdivided into four subgroups of 10 samples each. Groups Ia and IIa were treated as dry bonding groups, groups Ib and IIb were treated as a moist bonding groups, groups Ic and IIc were rewetted with Gluma desensitizer, and groups Id and IId were rewetted with vivasens desensitizer. Major group I was treated with Gluma comfort bond and Charisma. Major group II was treated Prime and Bond NT and TPH. The samples were thermo cycled and shear bond test was performed using an Instron machine. The data were analyzed using one-way analysis of variance and Tukey's Honestly significant different test.

RESULTS

The results revealed that the specimens rewetted with Gluma desensitizer showed the highest shear bond strength compared to all other groups, irrespective of the bonding agent or composite resin used.

CONCLUSIONS

It can be concluded that rewetting with desensitizer provided better bond strength than the other groups.

Self-organization of In2S3 quantum dots into fractal nanostructures by electrophoretic deposition

This paper describes the assembly of In2S3 quantum dots by electrophoretic deposition (EPD) and their subsequent self-organization into fractal nanostructures over ITO substrates. The surface morphology and the organization of these dots into nanostructures were analyzed using SEM, HRSEM and AFM techniques. These analyses reveal the existence, under appropriate conditions, of very unique nanoscale structural motifs and scale invariance associated with the assembly. Formation of such a well correlated assembly, although seems to be electric field driven, appears to be dominated by self-organizing mechanism. Such self-organized nano-scale structures consisting of cavities are likely to have fascinating condensed phase transport properties. The paper reports microscopic study of such fractal assemblies using SEM, HTSEM and AFM.

Use of CHROMagar in the differentiation of common species of Candida

CHROMagar has been reported to be useful for the rapid and accurate identification of Candida species. We tested 135 isolates of Candida species isolated from oropharyngeal candidiasis in HIV patients and found that it was useful in the presumptive identification of Candida albicans and Candida krusei. Occasional strains of C. tropicalis produced colonies with a greenish tinge making it difficult to differentiate from C. albicans.

Audit on flexible sigmoidoscopy for rectal bleeding in a district general hospital: are we over-loading the resources?

OBJECTIVE

Patients with rectal bleeding are being over investigated because of the fear of missing colorectal cancers. This study aimed to identify the percentage of patients <45 years of age who undergo flexible sigmoidoscopy for rectal bleeding, and to assess and compare the incidence of colorectal cancers and polyps above and below this age.

METHODS

Patients who underwent flexible sigmoidoscopy for rectal bleeding between 1 January 2000 and 31 December 2002 were reviewed. Patients were divided into two groups: group 1 consisted of patients aged >or=45 years and group 2 patients <45 years. The histopathology of biopsy specimens taken was also studied.

RESULTS

Altogether 18.9% of the patients who had flexible sigmoidoscopy for rectal bleeding were <45 years. The incidence of colorectal cancers in group 1 was 3.5%; all these cases were confirmed on histopathology. Only one patient in group 2 was diagnosed with colorectal cancer on flexible sigmoidoscopy, but the histopathology disproved it. The incidence of polyps was 16.6% in group 1 and 7.9% in group 2. Following histopathology, the incidence of adenomatous polyps was 6.8% in group 1 and 2.1% in group 2. There was a significant difference between the two groups, with a p value of <0.0001.

CONCLUSION

The incidence of colorectal cancers and adenomatous polyps in patients aged <45 years with rectal bleeding is very low. A flexible sigmoidoscopy costs approximately pound 330. If new guidelines are implemented considering the age of the patient, considerable cost savings could be made, and the available resources could be appropriately used in groups with high incidences of colorectal cancers.

An unusual case of gestational diabetes mellitus

The case of a woman, who developed gestational diabetes at six weeks in two successive pregnancies, is reported. She was in the high risk group to develop gestational diabetes. The first pregnancy terminated in abortion at 10 weeks. In the second pregnancy, institution of insulin therapy at diagnosis was associated with a successful outcome. This case highlights the need for screening for gestational diabetes at the first antenatal visit in the high risk group.

Enhanced activation of rhesus T cells by vectors encoding a triad of costimulatory molecules (B7-1, ICAM-1, LFA-3)

Since the rhesus is often used as a "gatekeeper" model for the evaluation of malaria and simian immunodeficiency virus (SIV)/HIV vaccines, the identification of strategies to enhance the activation of rhesus T cells would potentially aid in the generation of more potent vaccines directed against these infectious agents. Several molecules normally found on the surface of professional human APCs are capable of providing the second signals critical for T cell activation: B7-1 (CD80), ICAM-1 (CD54), and LFA-3 (CD58). With the exception of B7, T cell costimulatory molecules in the rhesus have not been identified. We have recently designed and characterized both recombinant vaccinia and recombinant avipox vectors containing the transgenes for a triad of human T cell costimulatory molecules (B7-1, ICAM-1, LFA-3; designated TRICOM). Here, we demonstrate the enhanced activation of rhesus T cells stimulated with rhesus APCs infected with TRICOM vectors in the presence of signal 1. Infection with TRICOM vectors led to significant improvement of APC capabilities in terms of reduction of the amount of signal 1 needed to activate naive T cells, and reduction in the amount of APCs required to activate T cells using a constant amount of signal 1. Antibody blocking studies demonstrated that each of the three costimulatory molecule transgenes contributed to the enhanced proliferation of T cells. TRICOM-enhanced T cell activation was shown to correspond to increases in type 1 cytokines and a reduced level of apoptosis. TRICOM-infected autologous B cells from rhesus immunized with either an SIV vaccine or a malaria vaccine stimulated significantly greater levels of IFN-gamma in response to specific peptide than stimulation with uninfected autologous B cells or B cells infected with wild-type vector. The ability to augment immune responses using poxvirus-based vaccines containing multiple costimulatory molecule transgenes can now be addressed in the rhesus macaque model.

Effector differentiation is not prerequisite for generation of memory cytotoxic T lymphocytes

The lineage relationship between short-lived effector T cells and long-lived memory cells is not fully understood. We have described T-GFP mice previously, in which naive and early activated T cells express GFP uniformly, whereas cells that have differentiated into effector cytotoxic T cells selectively lose GFP expression. Here we studied antigen-specific CD8 T cell differentiation using T-GFP mice crossed to the TCR transgenic (Tg) mice P14 (specific for the lymphocytic choriomeningitis virus glycoprotein peptide, gp33-41). After activation with antigenic peptide, P14XT-GFP CD8(+) T cells cultured in high-dose IL-2 developed into cells with effector phenotype and function: they were blastoid, lost GFP expression, expressed high levels of activation and effector markers, and were capable of immediate cytotoxic function. In contrast, cells cultured in IL-15 or low-dose IL-2 never developed into full-fledged effector cells. Rather, they resembled memory cells: they were smaller, were GFP(+), did not express effector markers, and were incapable of immediate cytotoxicity. However, they mediated rapid-recall responses in vitro. After adoptive transfer, they survived in vivo for at least 10 weeks and mounted a secondary immune response after antigen rechallenge that was as potent as endogenously generated memory cells. In addition to providing a simple means to generate memory cells in virtually unlimited numbers, our results suggest that effector differentiation is not a prerequisite for memory cell generation.

Dressed to kill? A review of why antiviral CD8 T lymphocytes fail to prevent progressive immunodeficiency in HIV-1 infection

CD8 T cells play an important role in protection and control of HIV-1 by direct cytolysis of infected cells and by suppression of viral replication by secreted factors. However, although HIV-1-infected individuals have a high frequency of HIV-1-specific CD8 T cells, viral reservoirs persist and progressive immunodeficiency generally ensues in the absence of continuous potent antiviral drugs. Freshly isolated HIV-specific CD8 T cells are often unable to lyse HIV-1-infected cells. Maturation into competent cytotoxic T lymphocytes may be blocked during the initial encounter with antigen because of defects in antigen presentation by interdigitating dendritic cells or HIV-infected macrophages. The molecular basis for impaired function is multifactorial, due to incomplete T-cell signaling and activation (in part related to CD3zeta and CD28 down-modulation), reduced perforin expression, and inefficient trafficking of HIV-specific CD8 T cells to lymphoid sites of infection. CD8 T-cell dysfunction can partially be corrected in vitro with short-term exposure to interleukin 2, suggesting that impaired HIV-specific CD4 T helper function may play a significant causal or exacerbating role. Functional defects are qualitatively different and more severe with advanced disease, when interferon gamma production also becomes compromised.

Changing thyroid status related to pregnancy

A case of post-thyroidectomy hypothyroidism is reported. The patient became euthyroid in three consecutive pregnancies, reverting to hypothyroid within three months of delivery on each occasion. The alteration in thyroid status is attributed to pregnancy related changes in antibody titres, though the laboratory data to confirm this are not available.

CD8 T cells specific for human immunodeficiency virus, Epstein-Barr virus, and cytomegalovirus lack molecules for homing to lymphoid sites of infection

CD8 T cells are classified as naïve, effector, or memory cells on the basis of CD45RA, CD62L, and CCR7 expression. Sequential engagement of cell-surface CD62L and CCR7 receptors is required for efficient trafficking to lymphoid tissue by means of high endothelial venules. Naïve CD8 T cells are CCR7(+)CD62L(+) CD45RA(+), whereas long-term memory cells are CCR7(+)CD62L(+)CD45RA(-). Effector cytotoxic T cells are thought to be CCR7(-)CD45RA(+). The distribution of CD8 subsets and cytolytic protein expression in healthy donors and donors seropositive for human immunodeficiency virus (HIV) were compared. In HIV-infected subjects, CCR7(-) CD8 T cells expanded at the expense of naïve and long-term memory cells. In both healthy donors and HIV-infected donors, CCR7(+) CD8 T cells were uniformly negative for perforin. In all subsets, perforin and granzyme A were not coordinately expressed, with perforin expression being more tightly regulated. The properties of CD8 T cells specific for cytomegalovirus, Epstein-Barr virus (EBV), and HIV were studied by staining with major histocompatibility complex peptide tetramers. Antigen-specific cells for chronic infections with these viruses were uniformly CCR7(-) and predominantly CD62L(-). In 2 HIV-seropositive donors, 3- to 4-fold fewer EBV-tetramer-positive cells were present in lymph nodes compared with blood. Antigen-specific CD8 T cells are therefore preferentially excluded from lymphoid sites, even when infection is primarily in lymphoid tissue. This may protect lymphoid tissues from immunopathological changes but compromise immune defense against viruses, such as HIV and EBV, that target lymphocytes. HIV-specific CD8 T cells do not express CD45RA, whereas EBV- and CMV-specific CD8 T cells are heterogeneous in CD45RA(+) expression. Lack of CD45RA expression may indicate incomplete differentiation of HIV-specific CD8 T cells to cytotoxic T cells.

Audit on prescription of long-term oxygen treatment

An audit was undertaken to assess the compliance to British Thoracic Society guidelines (1997) in the prescription of long-term oxygen treatment (LTOT) in Bassetlaw District General Hospital. A total of 34 patients were prescribed LTOT in our hospital between March 1993 and October 1998. The average age of patients was 71 years, 31 patients had COPD and three had chronic asthma. Only ten patients were clinically stable at the time of assessment. None of the measurements were repeated after a period of three weeks before prescribing LTOT. Adherence to guidelines in the prescription of LTOT was poor in our audit.

Effect of dietary copper on selenium toxicity in Fischer 344 rats

The purpose of this study was to investigate the ameliorating effects of dietary copper supplementation on selenium toxicity. Nine groups (n = 6) of weanling Fischer 344 female rats were randomly assigned to treatment groups and fed diets containing nontoxic levels of copper as CuCl2 and/or selenium as selenite or selenocystamine. Weight gain, liver and spleen weights, plasma lipid peroxidation, and liver selenium and copper content were analyzed after the 6-wk treatment period. Concentrations of up to 10 times the daily lethal dose of dietary selenium were well tolerated in rats supplemented with dietary copper. As the dietary level of selenium was increased, the ratio of selenium to copper measured in the liver decreased. In the groups of rats in which dietary copper supplementation was absent and dietary selenium was supplemented, copper stores in the liver remained unchanged from control values. Copper's protective effects from dietary selenium toxicity may come from the formation of a copper-selenide complex that renders both selenium and copper metabolically unavailable and nontoxic.

Impaired function of circulating HIV-specific CD8(+) T cells in chronic human immunodeficiency virus infection

The functional status of circulating human immunodeficiency (HIV)-specific CD8 T cells in chronically infected subjects was evaluated. By flow cytometry, only 5 of 7 subjects had detectable CD8 T cells that produced IFN-gamma after stimulation with HIV-infected primary CD4 T cells. In 2 subjects, the frequency of IFN-gamma-producing cells increased 4-fold when IL-2 was added to the culture medium; in another subject, IFN-gamma-producing cells could be detected only after IL-2 was added. IFN-gamma-producing cells ranged from 0.4% to 3% of CD8 T cells. Major histocompatibility complex-peptide tetramer staining, which identifies antigen-specific T cells irrespective of function, was used to evaluate the proportion of HIV-specific CD8 T cells that may be nonfunctional in vivo. CD8 T cells binding to tetramers complexed to HIV gag epitope SLYNTVATL and reverse transcriptase epitope YTAFTIPSI were identified in 9 of 15 and 5 of 12 HLA-A2-expressing seropositive subjects at frequencies of 0.1% to 1.1% and 0.1 to 0.7%, respectively. Freshly isolated tetramer-positive cells expressed a mixed pattern of memory and effector markers. On average, IFN-gamma was produced by less than 25% of tetramer-positive CD8 T cells after stimulation with the relevant gag or reverse transcriptase peptide. In all subjects tested, freshly isolated CD8 T cells were not cytolytic against peptide-pulsed B lymphoblastoid cell line or primary HIV-infected CD4 T-cell targets. Exposure to IL-2 enhanced the cytotoxicity of CD8 T cells against primary HIV-infected CD4 targets in 2 of 2 subjects tested. These results suggest that a significant proportion of HIV-specific CD8 T cells may be functionally compromised in vivo and that some function can be restored by exposure to IL-2.

Human immunodeficiency virus-specific circulating CD8 T lymphocytes have down-modulated CD3zeta and CD28, key signaling molecules for T-cell activation

Although human immunodeficiency virus (HIV)-infected subjects without AIDS have a high frequency of HIV-specific CD8 T lymphocytes, cellular immunity is unable to control infection. Freshly isolated lymphocytes often do not lyse HIV-infected targets in 4-h cytotoxicity assays. A large fraction of circulating CD8 T cells from HIV-infected donors down-modulate CD3zeta, the signaling component of the T-cell receptor complex, which is reexpressed in vitro coincident with the return of cytotoxic function. To investigate further the link between CD3zeta down-modulation and possible CD8 T-cell functional defects, we used flow cytometry to characterize further the properties of the CD3zeta-down-modulated subset. HIV-specific CD8 T cells, identified by tetramer staining, are CD3zeta(-). CD8 T cells with down-modulated CD3zeta also do not express the key costimulatory receptor CD28 and have the cell surface phenotype of activated or memory T cells (HLA-DR(+) CD62L(-)). After T-cell activation, CD3zeta-down-modulated cells express the activation marker CD69 but not the high-affinity interleukin 2 (IL-2) receptor alpha-chain CD25 and produce gamma interferon but not IL-2. Therefore HIV-specific CD8 T cells have down-modulated key signaling molecules for T-cell activation and costimulation and require exogenous cytokine stimulation. The typical impairment of HIV-specific CD4 T helper cells, which would normally provide specific CD8 T-cell stimulation, means that in vivo CTL function in vivo is compromised in most HIV-infected individuals. In AIDS patients, the functional defect is more severe, since CD3zeta is not reexpressed even after IL-2 exposure.

FHIT gene mutations and single nucleotide polymorphism in Indian oral and cervical squamous cell carcinomas

Genetic alterations at the FHIT (fragile histidine triad) tumor suppressor gene have been found in various human cancers. We have made an attempt to find point mutations of this gene in two different cancers from India, with entirely different etiologic factors: oral cancer (55 samples) caused by chewing tobacco and cervical cancer (43 samples) caused mainly by HPV (human papilloma virus) infection. Analysis of tumor DNA by the polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) method was performed on each of FHIT exons 5-9 individually, using exon-flanking primers. Two different mutations were identified in both oral and cervical tumors: one at the second nucleotide 3' to the termination codon (TGA) in exon 9 and the other at the ninth nucleotide upstream to the beginning of exon 9. These results indicate that mutations in the FHIT gene are rare events in these tumors in India (approximately 4%). In addition, we found a single nucleotide FHIT gene polymorphism which is due to T/A replacement at 17 nucleotides upstream to exon 9 where the A allele is 0.6 of the population.

A transgenic mouse model to analyze CD8(+) effector T cell differentiation in vivo

Antigen-specific effector T cells are prerequisite to immune protection, but because of the lack of effector cell-specific markers, their generation and differentiation has been difficult to study. We report that effector cells are highly enriched in a T cell subset that can be specifically identified in transgenic (T-GFP) mice expressing green fluorescent protein (GFP) under control of the murine CD4 promoter and proximal enhancer. Consistent with previous studies of these transcriptional control elements, GFP was strongly and specifically expressed in nearly all resting and short-term activated CD4(+) and CD8(+) T cells. However, when T-GFP mice were challenged with vaccinia virus, allogeneic tumor cells, or staphylococcal enterotoxin A, the cytotoxic and IFN-gamma-producing T cells lost GFP expression. Upon T cell receptor (TCR) ligation by alphaCD3, sorted GFP(+) cells fluxed calcium and proliferated vigorously. In contrast, GFP(-) effector cells showed a diminished calcium flux and did not proliferate. Instead, they underwent apoptosis unless supplied with exogenous IL-2. By reverse transcription-PCR analysis, the GFP(-) cells up-regulated the pro-apoptotic molecule, Fas-L, and down-regulated gene expression of the proximal TCR signaling molecule, CD3zeta, and c-jun, a component of the AP-1 transcription factor. Thus, differential regulation of TCR signaling may explain the divergent responses of naïve and effector T cells to antigen stimulation.

Viral-specific cytotoxic T lymphocytes lyse human immunodeficiency virus-infected primary T lymphocytes by the granule exocytosis pathway

Cytotoxic T lymphocytes (CTL) lyse antigen-bearing target cells by two distinct pathways. Whereas granule exocytosis targets any antigen-bearing cell, fas-mediated cytotoxicity kills only fas-expressing cells and does not require antigen expression. Fas pathway activation can potentially lead to lysis of uninfected bystander cells. We examined the relative usage of the two pathways by CTL clones and cell lines directed against four different human immunodeficiency virus (HIV) proteins in lysing primary HIV-infected targets. Although fas was expressed on HIV-infected primary CD4(+) T cells, their lysis by antigen-specific CD8(+) CTL was only by the granule pathway. Fas ligand (fasL) was not detectable on antigen-specific CD8 clones, T-cell lines, or circulating HIV-specific CD8 T cells from HIV-infected donors, stained with a tetrameric HLA-A2-HIV-peptide complex. FasL expression by HIV-specific CTL clones was not activated by exposure to HIV-presenting cells, but was after unphysiological stimulation with phorbol myristate acetate (PMA). CTL clones did not lyse bystander Jurkat cells, but HIV-infected primary CD4(+) T cells lysed uninfected bystander cells by the fas-mediated pathway. These results suggest that HIV-specific CD8(+) CTL do not cause HIV immunopathology by lysing bystander cells. On the contrary, fas-mediated lysis of uninfected cells by HIV-infected cells may contribute to CD4 decline.

Expansion of CD57 and CD62L-CD45RA+ CD8 T lymphocytes correlates with reduced viral plasma RNA after primary HIV infection

OBJECTIVE

CD8 T cells, expressing cell surface molecules distinct from those on resting and naive T cells, are increased in HIV infection. The association of increased CD38 and human leukocyte antigen DR (HLA-DR) CD8 T cells with poor prognosis has suggested that activated CD8 T cells may aggravate HIV infection. We examined whether other immunological parameters might influence the viral setpoint.

DESIGN

Peripheral T cells from nine untreated patients, obtained after primary HIV infection when plasma HIV had stabilized, were examined for proteins expressed in activated versus resting, memory versus naive, and cytolytic versus non-cytolytic T cells.

METHODS

The proportion of CD8 T cells that stain for CD38 and HLA-DR, CD28 and CD57 was compared with plasma viraemia and CD4 cell count. These parameters were also compared with the proportion of CD4 and CD8 T cells that express CD62L and CD45RA, present on naive cells and down-modulated in memory cells. Internal staining for the cytotoxic protein granzyme A was also examined.

RESULTS

An increase in CD38 and CD38 HLA-DR CD8 T cells correlated with increased plasma viral RNA (P < 0.00002, P < 0.03, respectively). An increase in CD8 T cells expressing granzyme A was associated with lower CD4 cell counts (P < 0.04). However, the expansion of CD57 and CD62L CD45RA+ CD8 T cells was associated with a lower viral setpoint (P < 0.01, P < 0.02, respectively).

CONCLUSION

Phenotypically defined activated CD8 T cells may have different functions in HIV infection. Activated CD8 T cells that are CD57 or CD62L(-)CD45RA+ may be beneficial, because their expansion in untreated patients correlates with a reduced viral setpoint after primary infection.

CNS interleukin-3 (IL-3) expression and neurological syndrome in antisense-IL-3 transgenic mice

Interleukin-3 (IL-3) is an important mediator of physiological and pathophysiological processes affecting the central nervous system (CNS). It stimulates the proliferation and activation of microglia and can enhance differentiation of cholinergic and sensory neurons. To examine the role of IL-3 in the CNS, we utilized transgenic mice expressing a murine antisense IL-3 (AS-IL-3) RNA under the control of the T cell B19 promoter so that expression is limited to hematopoietic cells. The AS-IL-3 transgenic mice develop either a progressive neurologic dysfunction, which includes ataxia, bradykinesia, and paralysis, or a lymphoproliferative syndrome. Histopathology demonstrated accumulations of reactive astrocytes in the cerebellum, brain stem, and spinal cord, accompanied by activated microglia. Partial loss of cerebellar nuclei neurons as well as neurons in the cranial nerve nuclei and spinal cord motor neurons is seen. Despite depletion of IL-3 peripherally, expression of IL-3 mRNA and protein is turned on in the CNS of the transgenic mice. Astrocytes cultured from the AS-IL-3 mice contain IL-3 mRNA and may thus be responsible for the activation of the microglia. This model should provide important insights into the role of cytokines in neurological disorders.