Efficacy and design requirements of UV light cabinets for disinfection of exchangeable non-sterilizable "dental objects"

Non-sterilizable items such as prosthodontics items constitute a high risk of transmitting dangerous pathogens, including Coronavirus, between patients and healthcare personnel. Although UV rays are recognized for their germicidal efficacy, large and expensive UV devices previously hindered their adoption in dental offices. During the COVID-19 pandemic, small UV devices became available for domestic use, albeit with varying designs and effectiveness. Our study assesses the disinfection capacity of a UV light cabinet for four dental materials and discusses crucial design features for effective performance. Specimens of each material (silicone impressions, stone cast, acrylic denture base, and indelible pencils) were contaminated with Escherichia coli Bl21, and randomly divided into three study groups: UV device (UVG), impressions disinfection solution (SG), and control (CG). The experiment was repeated thrice, and disinfection efficacy assessed by colony forming units (CFU) count. A 2.5-min UV exposure achieved full disinfection for all materials. Significantly different results were found between groups (p < 0.05, one-way ANOVA, Tukey HSD), except for indelible pencils, where UVG and SG were both highly effective. UV cabinets surpass SG's disinfection efficacy. Compact UV devices can offer affordable, portable, and efficient disinfection for non-sterilizable dental objects, with careful consideration of wavelength, exposure, intensity, and safety.

Emotional intelligence in preregistration nurse education

Emotional intelligence (EI) is considered essential to nursing practice, but it is unclear how best to support nursing students to develop EI skills. This article details a literature review that was undertaken to explore EI in preregistration nurse education and to identify effective methods for developing nursing students' EI skills. A total of 12 articles were included in the review, from which data were extracted, compared and categorised. Three main areas were identified regarding EI in preregistration nurse education: EI constructs, EI components and EI teaching methods. The review found that a range of EI constructs and components may be included in nurse education curricula, meaning that there is often inconsistency in the approaches used. Classroom teaching methods were primarily used, alongside online methods and experiential methods such as simulation-based learning. The findings of the review suggest there is a need for greater consistency in the EI constructs and components used in preregistration nurse education, as well as further research to determine which EI teaching methods are most effective.

Implications of different analgesic models on inflammatory markers after laparoscopic cholecystectomy

BACKGROUND

Despite its advantages, laparoscopic surgery causes significant shoulder and abdominal pain in 35%-80% of patients. The cause of post-laparoscopy pain is not fully understood, but it is assumed to be a multifactorial referred pain.

AIM OF THE STUDY

To evaluate the effect of different analgesia techniques on post-laparoscopic pain and inflammatory markers.

METHODS

Patients scheduled for elective laparoscopic cholecystectomy were randomly assigned to receive local hepatic and right subdiaphragmatic infiltration of one of the 4 study drug combinations: Group 1 (G1) received 20 ml bupivacaine 0.25%; Group 2 (G2) received 20 ml bupivacaine 0.25% +3 mg morphine sulphate; Group 3 (G3) received 20 ml bupivacaine 0.25% + 3 mg morphine sulphate +200 µg/kg ketamine; and Group 4 (G4) received 20 ml isotonic saline as the control group.

RESULTS

In G3, both shoulder pain on the verbal numerical rating scale and inflammatory marker levels were lower compared with the other groups. The highest levels of inflammatory markers were observed in the control group; this difference was statistically significant. No side effects or complications were observed in the study groups.

CONCLUSION

The addition of ketamine and morphine to bupivacaine for hepatic and subdiaphragmatic infiltration produced good analgesia and reduced inflammatory marker levels after laparoscopic cholecystectomy.

SERUM LIPOCALIN-2, AND FETUIN-A LEVELS IN PATIENTS WITH ALZHEIMER'S DISEASE

Alzheimer's disease is a neurodegenerative disease leading to a progressive and irreversible loss of mental functions. It is characterized by 3 stages according to the evolution and the severity of the symptoms. The authors of the present study aimed to investigate the levels of serum lipocalin-2, fetuin-A, and TNF-α in patients with Alzheimer's disease. 56 patients with Alzheimer's disease (the first group), and another 25 healthy volunteers (control group) were enrolled in this cross-sectional study. The serum levels of lipocalin-2, fetuin-A, and Tumor necrosis factor (TNF-α) were determined with the use of the ELISA method. There was a significant elevation in serum lipocalin-2, and TNF-α levels in the AD group (88.68±32.1) and(42.28±5.05) respectively, compared to the control group (63±28.5), and (35.19±5.07) respectively, [p<0.001]. A significant increase in serum concentration of lipocalin, TNFa with a reduction of fetuin-A could be considered an important phenomenon used for follow-up or prognosis and diagnosis of Alzheimer's disease.

Anti-diabetic effect of cotreatment with resveratrol and pioglitazone in diabetic rats

OBJECTIVE

Limitations and side effects associated with current anti-diabetic treatments have necessitated the search for new therapeutic alternatives. This study aimed to explore the combined use of resveratrol (RVT) and established anti-diabetic drug pioglitazone (PGZ) against streptozotocin (STZ)-induced diabetes mellitus (DM).

MATERIALS AND METHODS

 STZ was supplemented daily to Sprague-Dawley rats to induce DM. The synergistic effect of the RVT (20 mg/kg) and PGZ (0.65 mg/kg) on DM complications was evaluated after 8 weeks of treatment. Biochemical analyses were performed to evaluate the effectiveness of our treatment on glucose level, insulin sensitivity, lipid disturbances, oxidative mediators and inflammatory markers.

RESULTS

STZ induced DM onset that is accompanied with elevated diabetic markers, lipid disturbances, remarkable oxidative damage and hyper-inflammation. The PGZ+RVT combination has the best effect as illustrated by significant (p < 0.05) decreases in fasting blood glucose, insulin, HbA1c and HOMA-IR levels. This combination attenuated (p < 0.05) lipid disturbances and their associated elevated atherogenic biomarkers. At the same time, treatments with PGZ+RVT exhibited an anti-inflammatory effect as it attenuated the increase in inflammatory parameters (CRP, TNF-α, IL-6). Also, it restored total antioxidant capacity and peroxisome proliferator-activated receptor (PPARg) levels that decreased by STZ-DM induction.

CONCLUSIONS

This study provides PGZ+RVT as promising DM therapeutic alternative. This synergistic combination alleviates most of DM-related complications and insulin resistance.

A smart spirometry device for asthma diagnosis

In this paper an innovative prototype for smart asthma spirometry device to be used by doctors and asthma patients is presented. The novelty in this prototype relies in the fact that it is destined to subtend not only adults but offers an efficient and attractive manner to accommodate children patients as well thus, making it efficient for doctors, patients and parents to detect and monitor such intricate cases at stages as early as six years old. Moreover, the apparatus used enables us to integrate a vital parameter representing the Forced Expiratory Volume to the final diagnosis. Besides, the presented device will automatically diagnose those patients, assess their asthma condition, and schedule their medication process without excessive visits to medical centers whilst providing doctors with accurate and pertinent and comprehensive medical data in a chronological fashion. Zooming into under the hood of the device, a fully reliable hardware digital system lies along with a flowmeter detector and a Bluetooth emitter to interface with a user-friendly GUI-based application installed on smartphones which incorporates appealing animated graphics to encourage children to take the test. Furthermore, the device offers the capability of storing chronological data and a relevant resourceful display for accurate tracking of patients' medical record, the evolvement of their asthma condition, and the administered medication. Finally, the entire device is aligned with the medical requirements as per doctors' and telemedicine specialists' recommendations; the experiments carried out demonstrated the effectiveness and sustainable use of such device.

[Short and long term results of endolymphatic sac surgery: a patient-questionnaire based study]

INTRODUCTION

The endolymphatic sac surgery for the treatment of Meniere's disease has been described since the 1920s. The success rate of this technique in terms of vertigo control has been reported to be 50-80%. However, the value of this treatment method remained controversial. Furthermore, the reliable identification of the endolymphatic sac intraoperatively can be challenging in some cases. This study examines the short-, middle- and long-term results in a larger cohort of patients.

MATERIALS AND METHODS

In 74 patients, vertigo control, tinnitus and degree of satisfaction was evaluated by means of a questionnaire retrospectively. Additionally, the diagnostic value of the electrocochleography (EcochG) was determined.

RESULTS

The overall vertigo control rate was more than 70% in patients followed up for two years and has reached 81% in patients followed up for more than two years. Hearing preservation rate was 61%. Tinnitus has disappeared in 11% and improved in 23% of the patients. In 47% of the patients it was unchanged and in 19% worsened. The difference in EcochG results pre- versus postoperative was highly significant.

CONCLUSIONS

ELSS is a useful tool in the management of Ménière's disease, in particular in patients that do not benefit sufficiently from conservative therapy.

[Seroprevalence of toxoplasmosis in pregnant women in Rabat, Morocco]

In Morocco, the seroprevalence of toxoplasmosis in pregnant women living in Rabat, was estimated by analyzing antibodies (IgG, IgM) levels using an ELISA test. The analysis of 2456 serums at the Institut National d'Hygiène showed that the seroprevalence of toxoplasmosis is about 50.6%. According to the questionnaire, the lack of knowledge about this disease and soil contact could be the main causes of toxoplasmosis infection. The use of IgG avidity test has excluded a recent infection in 93.5% of pregnant women with IgM positive sera.

Pharmacokinetics and pharmacodynamics profiles of enalapril maleate in healthy volunteers following determination of enalapril and enalaprilat by two specific enzyme immunoassays

BACKGROUND AND OBJECTIVES

Most of the pharmacokinetic (PK) parameters for enalapril and enalaprilat were established following determination of the drug and its metabolite, using angiotensin converting enzyme (ACE) inhibition assays. In these methods, enalapril has to be hydrolysed to enalaprilat first and then assayed. The purpose of this study was to re-estimate the PK parameters of enalapril and enalaprilat in healthy volunteers using two specific enzyme immunoassays for enalapril and enalaprilat.

METHODS

The rate and extent of absorption of enalapril and enalaprilat from a 10-mg dose of two enalapril maleate commercial brands (Renetic and Enalapril) were estimated using a two-way-cross over design with 1-week washout period. Blood pressure was also measured at specified time intervals and correlated to enalaprilat plasma concentrations.

RESULTS

For enalapril, the AUC(o-->infinity) values (Mean+/-SD) were 450.0+/-199.5 and 479.6+/-215.6 ng h/mL, Cmax values were 313.5+/-139.6 and 310.1+/-186.6 ng/mL, Tmax values were 1.06+/-0.30 h and 1.13+/-0.22 h, and t1/2 ranged between 0.3 to 6.1 h (1.6+/-1.5) and 0.40 to 5.05 h (1.3+/-1.0), for the two brands. For enalaprilat, the AUC(o-->infinity) values were 266.9+/-122.7 and 255.9+/-121.8 ng h/ml, Cmax values were 54.8+/-29.5 and 57.2+/-29.0 ng/mL, Tmax values were 4.6+/-1.6 h and 4.3+/-1.45 h, and t1/2 ranged between 1.1 to 10.5 h (4.5+/-2.9) and 0.6 to 9.4 h (3.5+/-2.5) for the two brands.

CONCLUSIONS

Cmax values for enalapril are about 10 times those published in the literature and the rate and extent of absorption of the two brands of enalapril and their deesterification to enalaprilat following the administration of either brand were bioequivalent. Secondly, enalaprilat concentrations at 12-24 h following a single oral dose of enalapril in healthy volunteers were lower than those reported in the literature. The values reported here correlated with the return of blood pressure to predose level. Thirdly, enzyme immunoassays for enalapril and enalaprilat are better than ACE inhibition assays and can be used in bioequivalence assessment of enalapril and enalaprilat and for therapeutic drug monitoring in a clinical laboratory setting.

The Evolving Role of the Acute Assessment Unit - from inpatient to outpatient care

Acute Assessment Units (AAUs) have been developed to meet the demand for emergency care. Traditionally, AAUs have been an admission route to secondary care but the role is now evolving to assessment. AAUs are complex and have many interactions both in hospitals and the community. The effective functioning of an AAU requires excellent clinical leadership, appropriate facilities, timely access to diagnostics and input from the multi-disciplinary team. Increasingly, AAUs will have to develop services which are not dependent on using hospital beds. A variety of emergency medical presentations can, with the appropriate resources, be delivered in an out-patient setting.

Estrogen-dependent induction of persistent vaginal candidosis in naïve mice

The capacity of estrogen to induce vaginal candidosis (VC) in the absence of previous or concurrent Candida albicans infections was examined. Adult female Balb/c mice were evaluated for vaginal C. albicans burden, C. albicans-specific delayed type hypersensitivity (DTH) responses and vaginal lymphocyte population kinetics at several time-points while receiving weekly injections of 0.5 mg estrogen. Estrogen treatment resulted in the appearance of significant levels of C. albicans vaginal colonization, which persisted for a period of 4 weeks. A marked suppression of DTH responses mounted against subsequent C. albicans challenge was observed. Absolute number of vaginal T lymphocytes gradually increased by several folds especially at weeks 5-6 following the start of estrogen treatment. These results clearly indicate that estrogen, independent of other predisposing factors, is capable of perturbing the commensal relationship between the host and the fungus, which results in the induction of persistent VC.

The relationship between haptoglobin polymorphism and serum ceruloplasmin ferroxidase activity

The antioxidative potential of haptoglobin is type dependent; Hp2-2 has much lower antioxidative capacity than Hp1-1 or Hp2-1. It is therefore possible that other antioxidants may compensate for decreased antioxidative capacity in Hp2-2 individuals. Haptoglobin polymorphism was correlated with ceruloplasmin ferroxidase activity in a sample population of unrelated black Jordanians. Hp2-1 was the predominant type, occurring at a frequency of 0.518 and Hp2 was the common allele, occurring at a frequency of 0.6455; no Hp0-0 individuals were observed in the sample population. In general, haptoglobin concentration was highest among Hp1 homozygotes and lowest among Hp2 homozygotes, while ceruloplasmin ferroxidase activity was highest among Hp2 homozygotes and lowest among Hp1 homozygotes. Furthermore, ceruloplasmin ferroxidase activity was higher at haptoglobin concentrations >85 mg/dl compared with that at haptoglobin concentrations of 30-85 mg/dl, which was also higher than at haptoglobin concentrations <30 mg/dl, irrespective of haptoglobin type. These results suggest that ceruloplasmin ferroxidase activity is both haptoglobin type and concentration dependent.

Vaginal T lymphocyte population kinetics during experimental vaginal candidosis: evidence for a possible role of CD8+ T cells in protection against vaginal candidosis

Vaginal candidosis represents a significant health problem to women of childbearing age worldwide. It has been postulated that localized T cells play a role in protection against vaginal candidosis. In an attempt to evaluate the role of vaginal T cells in protection against vaginal candidosis, T cell population kinetics was evaluated using an oestrogen-dependent vaginal candidosis murine model. Vaginal T lymphocytes were isolated at different time points post C. albicans inoculation, viable cells were enumerated, phenotypically analysed for the expression of CD3, CD4 and CD8 T cell markers and absolute numbers of T cell subsets were calculated. Oestrogen-induced persistence of vaginal candidosis resulted in a significant increase in the total number of vaginal lymphocytes within 24-48 h post infection; increased vaginal lymphocyte numbers persisted throughout the infection period. The number of CD3+ T cells dramatically increased following C. albicans administration and was maintained at high levels throughout the infection period. The majority of CD3+ T cells were of the CD8+ type; however, considerable numbers of both CD4+ T cells and CD4+CD8+ T cells were also observed throughout the infection period. The considerable and persistent increase in vaginal T cell numbers in general and that of CD8+ T cells in particular are evidence of the possible role played by localized T cells in protection against vaginal candidosis.

Persistent colonization and transient suppression of DTH responses in an estrogen-dependent vaginal candidosis murine model

Recurrence of vaginal candidosis in women of childbearing age has been attributed to several predisposing factors including the presence of significant amounts of estrogen in the reproductive tract. In this study, the effect of estrogen on the level of C. albicans colonization, persistence of infection and suppression of DTH responses was investigated in an estrogen-dependent vaginal candidosis murine model. Mice were first injected subcutaneously with 0.5 mg of estradiol valerate 72 hours prior to C. albicans intravaginal inoculation and at weekly intervals thereafter for a period of up to 4 weeks; the inoculum consisted of 2 x 10(7) stationary-phase C. albicans blastoconidia in a volume of 20 microl. C. albicans colonization was evaluated in the spleen, liver, kidney, small intestine and reproductive tract of estrogen-treated and control mice 72 hours following inoculation, DTH responses were evaluated 2 and 5 weeks following primary inoculation and persistence of infection was evaluated at days 2, 3, 4, 8, 12, 19 and 26 post inoculation. Estrogen-treated mice exhibited higher levels of C. albicans colonization compared with control mice; this was most evident in the small intestine and reproductive tract. Estrogen treatment resulted in pronounced suppression of C. albicans-specific DTH responses; in that average footpad swelling was 4.7 mm in untreated mice compared with 2.3 mm in estrogen-treated mice. Long-term estrogen treatment resulted in the persistence of infection; in contrast, C. albicans infection resolved by day 8 post inoculation in untreated mice. DTH responses assayed 5 weeks post primary inoculation in treated mice were on average 4.1 mm, this was similar to that observed in untreated mice tested for DTH response 2 and 5 weeks post primary inoculation. These results suggest that, on the one hand, estrogen has an enhancing effect on C. albicans colonization and persistence of infection. On the other, estrogen seems to suppress DTH responses within the first 2 weeks post infection; persistence of infection under the influence of estrogen, however, seems to coexist with detectable systemic cell-mediated immunity.

Characterization of phenotype-based pathogenic determinants of various Candida albicans strains in Jordan

Sixty-six clinical isolates of Candida albicans representing 14 different strain types were tested for their phospholipase and proteinase activities in correlation with adherence to buccal epithelial cells (BECs) and lethality to mice. Variations in phospholipase and proteinase production as well as adherence to BECs were observed both among isolates of the same strain type and between isolates of different strain types. All isolates tested, irrespective of strain type, produced low levels of phopholipase (0.5 mm for strain -BCD- and 2.7 mm for strain ABC--) and acid proteinase (0.6 mm for strain A---E and 2.2 mm for strain --C--). A correlation was noted between adherence, phospholipase and proteinase production, and lethality to mice. C. albicans isolates, which adhered most strongly to BECs, exhibited higher levels of phospholipase and proteinase activities as well as higher pathogenicity. This was most evident in strain type --C--, which exhibited higher adherence ability (mean 717 +/- 21 yeasts/100 BEC), and proteinase activity (mean 2.2 mm), and relatively higher phospholipase activity (mean 2.4 mm) compared with those of other strains. Additionally, this type was more prevalent and showed significantly higher levels of tissue colonization in the liver, kidneys, and spleen compared with most other strain types in both subjects with healthy dentates and complete denture wearers. These results clearly demonstrate the significant role of phospholipase and proteinase activities on the adherence of C. albicans and their overall influence on the pathogenesis of Candida species.

Experimental trial on solo surgery for minimally invasive therapy: comparison of different systems in a phantom model

BACKGROUND

Robotic aid in minimally invasive surgery (MIS) is becoming more and more common. We designed an experimental trial in a phantom model to verify the feasibility of solo surgery for MIS. By performing laparoscopic cholecystectomy on a phantom model, we compared combinations of different systems available in terms of safety, comfort, and time requirements.

METHODS

Two surgeons skilled in endoscopic procedures tested the following systems as endoscope holders: the robotic system (AESOP), foot-controlled (AESOP 1000), and voice-controlled (AESOP 2000); the remote controlled FIPS Endoarm, electrically driven and controlled by a finger-ring joystic; the passive system TISKA Endoarm, a mechanical arm moved by hand and fixed by electromagnetical brakes. All of these systems combined with a second TISKA Endoarm as an instrument holder. A combination of two mechanical Martin arms, c, also was tested. The results were compared with those from a control group involving an assistant surgeon. A total of 70 experiments were performed.

RESULTS

The shortest dissection time was registered by the combination of two TISKA Endoarms, with a statistically significant difference as compared with the control group (p < 0.05) and experiments using AESOP 1000 (p < 0.05). The TISKA Endoarm also proved to be more comfortable when used as an instrument holder (p < 0.001 vs Martin arm), and rated second only to AESOP 2000 as an endoscope holder. The rating of AESOP 2000 as endoscope holder was significantly higher than that of all other groups (p < 0.001). The study proved the feasibility of solo surgery. The time needed for dissection was shortest when two TISKA Endoarms were used, demonstrating the possible advantages of solo surgery. The TISKA Endoarm received a subjective positive rating when used as both endoscope holder and instrument holder. The voice control of AESOP 2000 seemed to be a major improvement in the development of an optimal man-machine interface. Nevertheless, the system presents considerable space requirements and does not supply control of 30 degrees optics. The principle of the finger-ring joystick adopted by the FIPS Endoarm seemed very intuitive but lacking in ergonomy.

CONCLUSION

Laparoscopic solo surgery can be considered a safe procedure, although further technologic developments should lead to improved ergonomy, intuitiveness of handling, and architecture of the systems, offering the surgeon better control, increased precision of action, and reduction in operation time.

Age group-associated variations in the pattern of Hp type distribution in Jordanians

The relationship between haptoglobin (Hp) type and life expectancy was investigated by determining the pattern of Hp type distribution in 790 unrelated Jordanians divided into four age groups: A (1-19 years), B (20-39 years), C (40-59 years) and D (60-85 years). While the frequency of Hp 2-2 gradually decreased from 0.576 in A to 0.393 in D, the frequency of Hp 2-1 gradually increased from 0.348 in A to 0.526 in D. Hp2 allele decreased from 0.750 in A to 0.656 in D while that of Hpl allele increased from 0.250 in A to 0.344 in D. Hp type distribution in A, B and D age groups was in agreement with the Hardy-Weinberg equilibrium (HWE). These findings demonstrate that the pattern of Hp polymorphism varies in different age groups, indicating that life expectancy might be Hp phenotype-associated. Additionally, the results suggest that Hp 2-2 phenotype might be an age-associated risk factor.

The prevalence of type II diabetes mellitus is haptoglobin phenotype-independent

Haptoglobin (Hp) phenotype distribution and the association between Hp polymorphism and type II diabetes mellitus was investigated in a Jordanian sample population consisting of 618 nondiabetics and 265 diabetics. In nondiabetics, Hp 2-2 was the most predominant type occurring at a frequency of 0.529 followed by Hp 2-1 occurring at a frequency of 0.387. In diabetics, the Hp 2-2 frequency was 0.540 while that of Hp 2-1 was 0.381. No statistically significant variation was detected in Hp type distribution between the two groups. The Hp2 allele occurred at a frequency of 0.722 in nondiabetics and 0.730 in diabetics. In both groups, the Hp type distribution was in agreement with the Hardy-Weinberg equilibrium calculations. These results suggest that type II diabetes mellitus is Hp phenotype-independent.

Preferential repopulation of the small intestine by gut-derived T cell precursors in the murine system

The potential of intestinal intraepithelial lymphocyte (IEL) precursors to repopulate the lymphoid components of lethally-irradiated mice was evaluated. Mice injected with total IEL, or IEL depleted of mature T cells, died within 2 weeks post-irradiation. Injection of T cell-depleted Thy-1.1 IEL and Thy-1.2 bone marrow (BM) into lethally-irradiated Thy-1.2 mice resulted in survival rates greater than 90%. The vast majority of thymocytes analysed at 2, 6, and 10 weeks post-treatment were Thy-1.2+. The Thy-1.1+ and Thy-1.2+ cells were detected in the spleen 2 and 6 weeks post-reconstitution. After 10 weeks, the majority of splenic T cells were Thy-1.2+. The majority of Thy-1+ IEL were of the Thy-1.1 subtype at 2 and 6 weeks after reconstitution. After 10 weeks, Thy-1.2+ IEL became the predominant subtype. Flow cytometry (FCM) analyses of Thy-1.1+ IEL showed that Thy-1.1 was co-expressed with CD3, CD4, CD5, CD8, TCR alpha beta and TCR gamma delta T cell markers. These findings indicate that IEL precursors home preferentially to gut epithelia and generate complex IEL phenotypic subsets.

The role of adenosine receptor engagement in murine fetal thymocyte development

The role of adenosine receptor engagement in murine T-cell development was evaluated by culturing day 15-16 fetal thymic lobes in the presence of various concentrations of the adenosine receptor agonist 5'-(N-ethyl)-carboxamidoadenosine (NECA) or the adenosine receptor antagonist 8-phenyl-theophylline (8-PT) using the fetal thymic organ culture (FTOC) system. Before and 8 days after culture, thymocytes were isolated, counted, and analyzed for the expression of CD4 and CD8 T-cell differentiation molecules. Analysis of fresh thymocytes prior to culture showed that the majority of cells were of the CD4 single-positive or CD4+ CD8+ immature phenotype. Eight days after culture with media alone, 44% of cells were CD4+ and 23% were CD8+, and the number of viable thymocytes had increased from 1.7 x 10(5) to 2.2 x 10(5) cells per thymic lobe. A dose-dependent inhibition of maturation was observed in cultures with 8-PT, with greater than 85% inhibition at 50 microM. The double-positive thymocyte subset was most severely depleted. The number of cells obtained from cultures with NECA was also reduced, with about 65% inhibition at 50 microM, especially the CD8+ subset that was most severely affected. These results suggest that adenosine receptor engagement is required for normal T-cell differentiation and that adenosine receptor agonists and antagonists have distinct effects on thymocyte differentiation. An understanding of the cell-type-specific and developmental expression of adenosine receptors will help elucidate the mechanisms by which adenosine receptor engagement influences T-cell development.

Jordanian population data on the PCR-based loci: LDLR, GYPA, HBGG, D7S8 and GC

Genotype and allele frequency distributions for PM polymerase chain reaction (PCR)-based genetic markers were determined in a Jordanian sample population. Results were obtained using the AmpliType PM PCR Amplification and typing kit. All loci were in agreement with the Hardy-Weinberg equilibrium expectations. The predominant alleles for LDLR, GYPA, HBGG, D7S8 and GC loci were B, A, B, A and C respectively. No statistically significant variation was detected in allele frequencies of these loci in Jordanians compared to that in Israeli Arab, U.S Caucasian and Japanese populations. Data presented here can be used to estimate the frequency of a specific DNA profile in the Jordanian population for forensic analyses and paternity testing.

T cell progenitors in the murine small intestine

Lymphocytes in the murine small intestine epithelium are known to have a high proportion of extrathymic T cells. To explore the possibility that small intestine intraepithelial lymphocytes (IELs) are derived from T cell progenitors present within the intestine, intestine-derived cells with characteristics of early-stage T cell precursors were studied for their ability to regenerate IEL T cell populations following transfer into irradiated recipient mice. Cells within this population lacked markers of mature T cells but expressed heat-stable antigen, the c-kit receptor for stem cell factor, and/or the pre-T cell alpha gene. Upon adoptive transfer, donor cells preferentially homed to the intestine and did not repopulate the thymus or extraintestinal peripheral lymphoid tissues. IELs derived from the donor precursor pool included both (alpha beta and gamma delta T subsets and consisted of phenotypically heterogeneous cell populations defined by CD4 and CD8. These findings provide evidence that T cell progenitors located in the intestinal mucosa are the likely source of most intestinal IELs.

Stimulation via the CD43 coreceptor augments T cell proliferation during the early phase of antigen-induced activation

R2/60 is a monoclonal antibody (mAb) that recognizes the murine CD43 molecule expressed on mature T cells, developing thymocytes, and a subset of bone marrow hematopoietic stem cells. Recent studies using R2/60 demonstrate that CD43 is a costimulatory receptor involved in the activation of murine T cells. In the present study we have examined the kinetics of CD43-mediated costimulation in murine T cell populations including purified CD4+ and CD8+ peripheral T cells, and T cells activated in antigen-induced mixed-lymphocyte cultures. In each population, CD43 stimulation significantly enhanced T cell proliferation compared to non-CD43 activated cultures. CD43 costimulation was greatest in conjunction with suboptimal CD3 stimulation, and was most efficient during the early phase of antigen-driven activation, suggesting that under normal biologic conditions the role of CD43 may be to augment T cell responses early in immune activation.

T cell precursors in the spleen give rise to complex T cell repertoires in the thymus and the intestine

T cell precursors located in peripheral immune tissues have been studied according to the potential to repopulate the thymus and the gut of lethally irradiated mice. T cell repopulation could be achieved with spleen cells from athymic or euthymic mice thoroughly devoid of mature T cells. Repopulation did not occur with lymph node lymphocytes as determined from studies in congenic mice. The kinetics of T cell repopulation differed in the gut and thymus in that donor-derived T cells appeared in the gut by day 7 after cell transfer, and in the thymus by day 14 after cell transfer. The multipotent nature of splenic T cell precursors was evident from the finding that all major phenotypic subsets of T cells in the thymus and the gut developed after spleen cell transfer. T cell repopulation of the intraepithelial lymphocytes also occurred efficiently in athymic radiation chimeras injected with spleen cells from congenitally athymic nude mice, demonstrating that gut T cell repopulation by those cells does not require a functional thymus. PCR-spectratype analyses of twenty-four V beta TCR genes in thymocytes and intraepithelial lymphocytes revealed extensive TCR-beta repertoires in both tissues 1 to 2 wk after cell transfer, although T cells with rearranged TCR were undetectable in the donor spleen cell population. The minimal phenotype of the splenic T cell precursor was determined to be CD3-, CD4-, CD8-, HSA+.

T cell precursors in the spleen give rise to complex T cell repertoires in the thymus and the intestine

T cell precursors located in peripheral immune tissues have been studied according to the potential to repopulate the thymus and the gut of lethally irradiated mice. T cell repopulation could be achieved with spleen cells from athymic or euthymic mice thoroughly devoid of mature T cells. Repopulation did not occur with lymph node lymphocytes as determined from studies in congenic mice. The kinetics of T cell repopulation differed in the gut and thymus in that donor-derived T cells appeared in the gut by day 7 after cell transfer, and in the thymus by day 14 after cell transfer. The multipotent nature of splenic T cell precursors was evident from the finding that all major phenotypic subsets of T cells in the thymus and the gut developed after spleen cell transfer. T cell repopulation of the intraepithelial lymphocytes also occurred efficiently in athymic radiation chimeras injected with spleen cells from congenitally athymic nude mice, demonstrating that gut T cell repopulation by those cells does not require a functional thymus. PCR-spectratype analyses of twenty-four V beta TCR genes in thymocytes and intraepithelial lymphocytes revealed extensive TCR-beta repertoires in both tissues 1 to 2 wk after cell transfer, although T cells with rearranged TCR were undetectable in the donor spleen cell population. The minimal phenotype of the splenic T cell precursor was determined to be CD3-, CD4-, CD8-, HSA+.

Heat-stable antigen may be an early marker of extrathymic murine intestinal intraepithelial lymphocytes

Using a system of bone marrow (BM) hematopoietic repopulation of irradiated euthymic and athymic mice, we have examined the early stages of extrathymic T-cell development within the murine small intestine epithelium. During a period of active extrathymic T-cell development, two distinct populations of intraepithelial lymphocytes (IEL) were present. One consisted of CD3+ lymphocytes with phenotypic properties of mature IEL. The other population consisted of a transient IEL subset that increased in abundance between days 5 and 14 post-BM transfer, and then declined. The majority of transient IEL in both types of mice expressed the heat-stable antigen, of which some cells coexpressed CD3 but were void of other markers common to mature T cells. Studies using freshly extracted IEL from normal nonirradiated mice found that approximately 3% to 5% of the IEL had phenotypic properties similar to the transient IEL observed during repopulation of radiation chimeras, indicating that such IEL are present within the gut epithelium of normal, nonirradiated mice. Identification of this IEL subset should greatly facilitate studies of extrathymic IEL development.

A novel marker of murine bone marrow hematopoietic stem cells that is expressed on peripheral T cells and is associated with a functionally important molecule on activated cytotoxic T lymphocytes

A MAb (R2/60) has been isolated that defines a novel lymphocyte marker of murine T cells. The determinant recognized by MAb R2/60 is present on a subset of bone marrow (BM) hematopoietic stem cells, on adult thymocytes, on peripheral T cells (both resting and activated), and on murine T cell tumor lines, although it is not expressed on mature B cells. In immunoprecipitation studies using radiolabeled membrane lysates from adult thymocytes, MAb R2/60 precipitated a 44-kDa membrane-bound dimer. Functionally, MAb R2/60 mediated antigen-independent cell lysis by activated CTLs, and by CTL clones, when bridged to Fc receptor-bearing target cells; however, binding of MAb R2/60 to effector cells prior to cytotoxic assays did not inhibit target cell lysis by CTLs, suggesting that the R2/60 determinant is involved in transmembrane signaling to already activated CTLs, but that it is not involved in target cell adhesion or antigen recognition. Moreover, direct stimulation of T cells by MAb R2/60 in the absence of additional stimuli did not induce cell proliferation, further implying that the R2/60 determinant is functionally involved in the effector rather than the inductive phase of the T cell response.

Phenotypic and functional heterogeneity of murine intestinal intraepithelial lymphocytes defined by cell density: implications for route of differentiation and responsiveness to proliferation induction

The phenotype and function of murine intestinal intraepithelial lymphocytes (IEL) was studied in a Percoll-fractionated preparation that consisted of low-density cells which migrated to the 40-50% Percoll interface (IEL-40), medium-density cells which migrated to the 50-55% interface (IEL-50), and high-density cells which migrated to the 55-70% interface (IEL-55). IEL-40 and IEL-50 cells, the subsets phenotypically most similar to mature IEL, consisted of CD3+ T cells that included CD4- CD8+ and CD4+ CD8+ cells; CD4+ CD8- cells were present only in the IEL-50 fraction. T-cell receptor (TcR)alpha beta and TcR gamma delta cells were present in both IEL-40 and IEL-50 fractions. In contrast, most IEL-55 were CD3-, heat-stable antigen (HSA)+ cells that were not B cells; some IEL-55 cells were CD3lo HSA- or CD3lo HSA+ suggesting that IEL-55 are immature T cells. TcR alpha beta but not TcR gamma delta was expressed in the IEL-55 fraction. All three IEL fractions consisted of both CD8 alpha alpha and CD8 alpha beta cells. There was considerable functional heterogeneity between the three IEL fractions such that CD3-induced proliferation was greatest for IEL-50 cells and least for IEL-55 cells; that activity correlated with the proportion of Thy-1+ cells within the fractions. Both IEL-40 and IEL-50 fractions contained activated cytotoxic T lymphocytes (CTL) that were 8-16-fold more lytic than IEL-55 cells. That IEL-55 cells may be precursors of some IEL-40 and IEL-50 cells was demonstrated by a shift in cell density and by an increase in proportions of cells expressing markers of IEL-40 and IEL-50 cells following in vitro stimulation via CD3. The relevance of these findings to differences in functional activities reported for murine IEL is discussed.