Implementation of Test-to-Stay programming to minimize learning loss in a pre-K-8 school district.

OBJECTIVES: Determine if a school-based Test-to-Stay (TTS) program designed to minimize learning loss reduced the incidence of COVID-19 in a US primary school district. STUDY DESIGN: Observational, simple summary analysis of attendance and effectiveness of a TTS program implemented in a California school district. METHODS: Retrospective analysis of nested medical and demographic data. Survival curves were plotted using a cumulative hazard function to compare the probability of infection among close contacts exposed at school at different points of time between participants who participated in TTS versus those who did not participate in TTS. A Cox proportional hazards regression model with time-dependent covariates was used to estimate the association of TTS status with the incidence of SARS-CoV-2 infection. RESULTS: Univariate Cox regression analysis revealed that after adjustment, enrollment in TTS was negatively correlated with the risk of SARS-CoV-2 infection (hazard ratio 0.096; 95% confidence interval [CI], 0.024-0.390; P < 0.001). CONCLUSIONS: TTS is an effective component of a layered protection strategy to prevent COVID-19 transmission in schools and communities, while minimizing the loss of in-person instruction in primary schools.

Adjustment for time-invariant and time-varying confounders in 'unexplained residuals' models for longitudinal data within a causal framework and associated challenges.

'Unexplained residuals' models have been used within lifecourse epidemiology to model an exposure measured longitudinally at several time points in relation to a distal outcome. It has been claimed that these models have several advantages, including: the ability to estimate multiple total causal effects in a single model, and additional insight into the effect on the outcome of greater-than-expected increases in the exposure compared to traditional regression methods. We evaluate these properties and prove mathematically how adjustment for confounding variables must be made within this modelling framework. Importantly, we explicitly place unexplained residual models in a causal framework using directed acyclic graphs. This allows for theoretical justification of appropriate confounder adjustment and provides a framework for extending our results to more complex scenarios than those examined in this paper. We also discuss several interpretational issues relating to unexplained residual models within a causal framework. We argue that unexplained residual models offer no additional insights compared to traditional regression methods, and, in fact, are more challenging to implement; moreover, they artificially reduce estimated standard errors. Consequently, we conclude that unexplained residual models, if used, must be implemented with great care.

Local public knowledge of blood donation systems in Trinidad and Tobago and in other places

OBJECTIVE: To investigate the Trinidad and Tobago (TRT) public’s knowledge of donation procedures locally and in the United States (USA) and United Kingdom (UK) and its effect on willingness to donate blood locally. DESIGN AND METHODS: A cross sectional study was conducted on a convenience sample from adults in TRT concerning knowledge and attitudes towards blood donation. Data was collected using an interviewer-administered questionnaire. 529 responses were received. Analysis was performed using SPSS Statistics 21. Chi-squared testing was done to determine statistical significance. RESULTS: Of 529 respondents, 141 (26.7%) had donated previously, 34 (6.4%) had been excluded and 354 (66.9%) had never donated. 76.8% of those who had donated did so for a friend or family member. 53.6% of respondents rated their knowledge of TRT’s system, and 86.2% rated that of the US and UK, as ‘poor’ or ‘very poor’. Knowledge of the local system was directly correlated to willingness to donate blood in TRT (p<0.001). No relation was found concerning knowledge of the foreign systems and local willingness to donate (p=0.423). Factors deemed most ‘likely’ or ‘very likely’ to influence people to donate included: if donation was for an ill family member (87.7%) or friend (77.9%); if the blood donation system in place was a replacement system (70.9%) and if more information was given to the public about blood donation (67.3%). CONCLUSION: Public knowledge of the blood donation system of TRT affected willingness to donate while knowledge of the US and UK systems had no effect.

Out-of-hospital cardiac arrest in South Asian and white populations in London: database evaluation of characteristics and outcome.

OBJECTIVE: To compare out-of-hospital cardiac arrest (OOHCA) characteristics in white and South Asian populations within Greater London. METHODS: Data for OOHCAs were extracted from 1 April 2003 to 31 March 2007. Primary study variables included age, gender, ethnicity, response times from 999 call to ambulance arrival, initial cardiac rhythm, whether bystander cardiopulmonary resuscitation was provided before arrival of the London Ambulance Service (LAS) NHS Trust crew, whether the arrest was witnessed (bystander or LAS crew) and hospital outcome, including survival to hospital admission and discharge. RESULTS: Of 13 013 OOHCAs of presumed cardiac cause, 3161 (24.3%) had ethnicity codes assigned. These comprised 63.1% (n = 1995) white and 5.8% (n = 183) South Asian people, with the remainder from other backgrounds. White patients were on average 5 years older than South Asians (69.5 vs 64.6, p<0.005). Response time (7.48 min vs 7.46 min), bystander cardiopulmonary resuscitation (34.4% vs 29.7%), initial cardiac rhythm (29.5% vs 30.4%) and survival to admission (22.2% vs 22.5%) and discharge (8.7% vs 8.9%) were comparable between the two ethnic groups. South Asians were slightly more likely to have a witnessed an OOHCA than their white counterparts (OR = 1.1, 95% CI 1.0 to 1.2). DISCUSSION: The quality of care provided was comparable between white and South Asian populations. The data support the emerging view that South Asians' high mortality from coronary heart disease reflects higher incidence rather than higher case fatality. South Asians had an OOHCA at a significantly younger age. The study demonstrates the importance of ethnic coding within the emergency services.

Acetaminophen-induced proliferation of breast cancer cells involves estrogen receptors.

Previous studies have shown that acetaminophen, a common analgesic/antipyretic, induces proliferation of cultured breast cancer cells containing both estrogen and progesterone receptors (ER+/PR+). The main objective of this study was to evaluate the involvement of ERs in this effect. First, the effects of therapeutic acetaminophen concentrations were compared in breast cancer cells with high ERs and in T47Dco cells with lower ERs, to determine if acetaminophen-induced proliferation depends on ER levels. Second, the effects of two antiestrogens (ICI 182,780 and 4'-hydroxytamoxifen) on acetaminophen-induced proliferation were determined in three human breast cancer cell lines: two ER+/PR+ (MCF7, T47D) and one ER-/PR- (MDA-MB-231). Third, ER binding assays were performed in MCF7 cells to determine if acetaminophen competed with estradiol for binding to ERs. Proliferation endpoints monitored included percent cells in the DNA synthesis phase of the cell cycle, 3H-thymidine incorporation into DNA, and cell number. Acetaminophen did not induce DNA synthesis in T47Dco cells, but did in cells with higher ER levels, suggesting high ER levels are necessary for acetaminophen to induce proliferation. Antiestrogens inhibited acetaminophen-induced proliferation in ER+/PR+ cells while no effects were observed in ER-/PR- cells, further supporting ER involvement. However, acetaminophen did not compete with estradiol for binding to ERs in ER+/PR+ cells. Collectively, these data suggest that acetaminophen induces breast cancer cell proliferation via ERs without binding to ERs like estradiol. The second purpose of this study was to determine if acetaminophen is estrogenic/antiestrogenic in vivo (uterotrophic assays). Acetaminophen has no antiestrogenic/estrogenic activity in mice or rats uteri.

Complete prevention of the clinical expression of adjuvant-induced arthritis in rats by cyclosporin-A and lobenzarit: the regulation of lymph node cell populations and cytokine production.

A single dose of either cyclosporin-A (CsA) or lobenzarit (CCA) given with an arthrogenic adjuvant completely prevented expression of experimental adjuvant arthritis in rats. The aim of this study was to understand how these drugs prevented the arthritis expression by studying the popliteal lymph nodes draining the arthritic joints at various times after adjuvant injection. Neither drug affected the proliferation in popliteal lymph nodes at the time arthritis was normally expressed, however, there was a marked change in the types of cells present. Immunofluorescence assays showed a reduction in the proportion of CD4+ cells, while the proportion of B-lymphocytes was almost doubled. This coincided with a marked elevation in the ability of these cells to produce interleukin (IL)-6. At the same time production of other cytokines (IL-2, tumour necrosis factor (TNF) and interferon (IFN)-gamma) was not greatly affected. However, one day after adjuvant injection IL-2 and IFN-gamma production was reduced. In vitro experiments showed that IL-6 production by lymphoid cells was relatively unaffected by CsA and CCA but IL-2, TNF and IFN-gamma were suppressed by CsA. The results indicate that CsA and CCA may modify the response to the arthritic adjuvant by specifically inhibiting IL-2, TNF and IFN-gamma production at the time of adjuvant injection. The lack of inhibition of IL-6 by these drugs reveals it may not play a key role in the initiation of this model of chronic inflammation.

Signal transduction via Fc gamma R and Mac-1 alpha-chain in monocytes and polymorphonuclear leucocytes.

Some (VIM12, Leu-15, 5A4.C5), but not all, Mac-1-specific monoclonal antibodies (mAb) induced a clear respiratory burst in unprimed monocytes but not in unprimed polymorphonuclear leucocytes (PMN). We showed that this monocyte stimulation occurred via formation of Mac-1 mAb-Fc gamma RI or Mac-1 mAb-Fc gamma RII complexes, as human monomeric IgG1 could completely block the respiratory burst induced by the murine IgG2a subclass anti-Mac-1 mAb Leu-15 and the Fc gamma RII-specific mAb IV.3 inhibited respiratory burst formation by IgG1 subclass anti-Mac-1 mAb VIM12 and 5A4.C5, respectively. F(ab')2 fragments of mAb VIM12 did not stimulate. This association between Mac-1 and Fc gamma RII may be due to a near spatial association between these molecules in monocytes, as we observed partial inhibition of FITC-labelled anti-Fc gamma RII mAb IV.3 binding after prior incubation with mAb VIM12. If monocytes were preincubated with mAb IV.3 or aggregated IgG, there was partial inhibition of mAb VIM12 binding. The non-stimulating anti-Mac-1 mAb (JML.H11,44, OKM1, LM2/1, Mo1) did not show any significant competition with mAb IV.3 binding to Fc gamma RII. Both non-stimulating CD18-specific mAb, however, showed strong competition with mAb IV.3 binding to Fc gamma RII. On unprimed PMN, the situation was different. No Mac-1-specific mAb induced a respiratory burst and there was no competitive inhibition between anti-Mac-1 mAb and antibodies binding to Fc gamma RII. In interferon-gamma (IFN-gamma)-primed PMN, however, we observed a functional association between Mac-1 and Fc gamma RI as IgG2a subclass mAb Leu-15 induced a respiratory burst which could be inhibited by monomeric human IgG1, as observed in monocytes. However, no other anti-Mac-1 mAb was able to induce a respiratory burst in IFN-gamma-primed PMN. Therefore, a similar signal transducing capability may exist between Mac-1 and Fc gamma RI on both monocytes and PMN, despite a different relationship between Mac-1 and Fc gamma RII on these cell populations. As no Mac-1 beta-chain-specific (CD18)mAb were able to induce a respiratory burst in monocytes, despite being able to interact with Fc gamma R via their Fc regions, as detected by competition with mAb IV.3 for binding to Fc gamma RII, we conclude that intracellular signalling via Mac-1 mAb-Fc gamma RII complexes requires the alpha-chain.

Is aspirin a prodrug for antioxidant and cytokine-modulating oxymetabolites?

Aspirin and salicylate are transformed by stimulated human polymorphonuclear leucocytes (PMN), likely to be found at inflammatory sites, into both 2,3- and 2,5-dihydroxybenzoates (DHB). These DHB inhibit both the production of hydrogen peroxide by stimulated human PMN and prostaglandin (PG) E2 by activated rat macrophages. In contrast, DHB stimulated production of interleukin (IL)-1 and tumour necrosis factor (TNF) but inhibited IL-6 production by rat macrophages. These effects were probably a consequence of PGE2 inhibition. Gentisate (2,5-DHB) and homogentisate (a tyrosine metabolite) inhibited the lymphoproliferative action of IL-1. Some related phenols, e.g. 5-aminosalicylate, inhibited H2O2 production but had little effect on PGE2 production. These findings suggest that the local synthesis of DHB may contribute to the overall anti-inflammatory activity of salicylate, which (unlike aspirin) has little direct effect on PG production.

Placental protein 14 secretion during in vitro fertilization cycles with and without human chorionic gonadotropin for luteal support.

OBJECTIVE: To investigate levels of placental protein 14 (PP14) in in vitro fertilization (IVF) patients with and without exogenous human chorionic gonadotropin (hCG) for luteal support. DESIGN, PATIENTS: Thirty-one women undergoing IVF were studied. For 18 women, hCG was administered in the luteal phase, and 12 became pregnant. Five pregnancies occurred in 13 women not receiving exogenous hCG. SETTING: All the patients attended the University of Southampton/Chalybeate Hospital IVF program. RESULTS: There was no change in PP14 levels 2 days after embryo transfer (ET), but small significant rises were noted by day 8 in all patients. Thereafter, levels rose further in pregnant subjects but showed no change in nonpregnant patients. The highest level of PP14 was seen in the group of women on hCG support, but there was no overall statistical difference between those on support and those not. In the nonpregnant group, there was no significant correlation between progesterone (P) and PP14 8 days from ET, whereas a highly significant correlation was noted in the pregnant group. CONCLUSIONS: Neither hCG nor P are primary factors in the control of endometrial PP14 secretion, but PP14 and P may have common underlying control mechanisms.

Comparison of techniques for the assessment of polymorphonuclear leukocyte polarisation in suspension.

Polarisation of polymorphonuclear leukocytes (PMN) in suspension was assessed using three techniques: 1) visual classification; 2) computerised morphometry; and 3) flow cytometry. While visual classification detected the formation, polarisation and type of cytoplasmic extensions produced by PMN, morphometry and flow cytometry detected only the formation of extensions. The area, perimeter and ellipticity were, in general, statistically different for each subtype of PMN-shape identified by visual classification. Furthermore, the magnitude and direction of changes detected by flow cytometry were affected by the use of erythrocyte lysis (during isolation of the cells) and the fixative used prior to analysis. The findings of this study demonstrate that visual classification is a more sensitive, reliable and appropriate assay of PMN polarisation than current morphometric and flow cytometric methods.

The detrimental influence of functional ovarian cysts during in-vitro fertilization cycles.

Reviewing 780 in-vitro fertilization (IVF) cycles, where buserelin was commenced in the preceding luteal phase and human menopausal gonadotrophin on day 4 of the ensuing menses, 53 cycles were identified with sonolucent cysts (30-50 mm diameter). Of the latter 53 cycles, the serum oestradiol was significantly greater on day 4 in 22 cycles abandoned for poor follicular development than in 31 cycles which proceeded to oocyte retrieval (P less than 0.05). Of the 31 cycles proceeding to oocyte retrieval, nine had a day 4 serum oestradiol greater than 200 pmol/l (95th centile for day 4 oestradiol in patients without apparent cysts), and these cycles produced significantly fewer grade 1 embryos than the cycles with day 4 oestradiol levels less than or equal to 200 pmol/l (P less than 0.05). Six of the 53 cycles with cysts resulted in conception, and all of these cycles had a day 4 serum oestradiol less than 200 pmol/l. Among the 53 cycles with ovarian cysts, the serum progesterone on the day of abandonment in four cycles and on the day of human chorionic gonadotrophin administration in one non-abandoned cycle, was above the range established for 104 cycles without cysts. No significant difference was seen in day 4 serum androstenedione levels, and the day 4 serum progesterone was less than 5 nmol/l in all but one patient. Functional activity of ovarian cysts is associated with an adverse influence on IVF cycles.

Co-existence of coeliac disease and insulin-dependent diabetes mellitus in children: screening sera using an ELISA test for gliadin antibody.

The prevalence of coeliac disease in children with insulin-dependent diabetes mellitus was investigated using a screening test of serum for antigliadin antibody by ELISA. One hundred and eighty (180) unselected diabetic children were screened for IgA and IgG class antigliadin antibodies (AGA); children with either grossly elevated or slightly elevated AGA had small bowel biopsies. The four children with the highest IgA AGA had total villous atrophy. These four children were considered to have unsuspected coeliac disease. The prevalence of coeliac disease in this group of children was one in 45. Anti-gliadin IgA and IgG tests are suitable for screening children at high risk of having coeliac disease.

Two new anti-rat macrophage monoclonal antibodies.

There are relatively few monoclonal antibodies (MAbs) to rat monocyte/macrophages available. We describe here 2 new such antibodies. The first, 109.2, recognizes most rat monocyte/macrophages and all polymorphs. The antigen recognized by this antibody is upregulated by 15 mins exposure to PMA (Phorbol myristate acetate) but down regulated by overnight exposure to LPS (lipopolysaccharide). It is probably an adhesion molecule and is likely to represent the rat equivalent of CD11b. The second antibody, 112.1, recognizes lysozyme in rat macrophages, particularly alveolar macrophages. In addition it also recognizes lysozyme in hen, rabbit and human macrophages. It also recognizes lysozyme in other tissues such as Paneth cells and proximal renal tubular cells.

Phenotypic analysis of functionally associated molecules on peripheral blood and synovial fluid monocytes from arthritis patients.

Surface expression of 16 different membrane molecules was analyzed in peripheral blood and synovial fluid monocytes from patients with rheumatoid arthritis and reactive arthritis compared to controls. The most significant findings were modulated expression of function-associated FcRI, CR1, CR3, MHC class II and activation-associated CD31, M5, and M6 molecules in arthritis patients compared to controls. Of these molecules, only upregulated expression of MHC class II has previously been reported in synovial fluid monocytes of patients with rheumatoid arthritis.

Comparison of 'poor' responders with 'good' responders using a standard buserelin/human menopausal gonadotrophin regime for in-vitro fertilization.

This study identifies a group of 87 patients, who demonstrated a 'poor' response to a standard buserelin/human menopausal gonadotrophin (HMG) regime. The subsequent outcome in 61 of these 'poor' responders when treated with a higher dose of HMG to achieve a satisfactory response was compared with 250 patients, who showed a 'good' response to the standard regime. 'Poor' responders were significantly older than 'good' responders (P less than 0.001), but no significant difference was demonstrated in the indication for in-vitro fertilization (IVF). Even on higher doses of HMG, 'poor' responders took longer for their follicles to achieve maturity than the 'good' responders (P less than 0.01). 'Poor' responders produced 8.9 oocytes per oocyte collection compared to 11.8 in the 'good' responders (P less than 0.01). The fertilization rate was significantly lower in the 'poor' responders compared to the 'good' responders (P less than 0.01). Although there was no significant difference in morphometric grading between 'poor' responder embryos and 'good' responder embryos, the rate of cell division was significantly slower in embryos of the 'poor' responders than the 'good' responders (P less than 0.01). The pregnancy rate per oocyte retrieval was 9% in the 'poor' responders compared to 29% in the 'good' responders (P less than 0.01). The implantation rate in the 'poor' responders was 4.4% compared to 16.1% in the 'good' responders (P less than 0.001).

Biochemical monitoring during hormone replacement therapy cycles for transfer of cryopreserved embryos in patients with functional ovaries.

Biochemical monitoring was undertaken in 22 treatment cycles for women with normal ovarian function who underwent pituitary suppression with buserelin and administration of exogenous oestradiol (E2) and progesterone (P) for cryopreserved embryo transfer (ET). Eighteen transfers of 1-4 thawed embryos, on the third day of exposure to progesterone, resulted in five clinical pregnancies (27.8%) and one biochemical pregnancy. There was no difference between pregnant and non-pregnant patients in the number and quality of embryos transferred, age, weight or infertility diagnosis. Serum E2 level from days 10-17 (the late proliferative phase) of the therapy cycle were significantly higher in the pregnant group compared with the non-pregnant group (P less than 0.05--P less than 0.005). There were no significant differences in P levels between the two groups from the onset of progesterone administration to the end of the cycle. However, as might be expected, the mean E2/P molar ratio in the pregnant group was significantly higher at the time of ET (P less than 0.02). It is concluded that biochemical monitoring during the embryo replacement cycle is necessary to tailor drug dosages for individual requirements to achieve adequate E2 levels before ET. Alternative routes of oestradiol administration need to be considered in patients with poor E2 profiles.

Analysis of function-associated receptor molecules on peripheral blood and synovial fluid granulocytes from patients with rheumatoid and reactive arthritis.

In this study we report the expression pattern of 13 different function-associated surface molecules on synovial fluid and peripheral blood granulocytes from rheumatoid and reactive arthritis patients. We found increased expression of the complement receptors 1 (CD35) and 3 (CD11b) and of the activation-associated antigens CD67, CD24, and M5 on synovial fluid granulocytes from rheumatoid and/or reactive arthritis patients compared to autologous peripheral blood granulocytes. In addition, synovial fluid granulocytes expressed IgG Fc receptor 1 (CD64) and complement receptor 4 (CD11c), neither of which can be found on peripheral blood granulocytes. Peripheral blood granulocytes from rheumatoid and reactive arthritis patients expressed higher levels of leucocyte function-associated antigen 1 (CD11a) and of the membrane proteins CD31, CD24, M5, and M6 compared to peripheral blood granulocytes from healthy controls and patients with degenerative joint disease. No significant differences in the expression of any of the molecules studied could be observed between cells from rheumatoid and cells from reactive arthritis patients, suggesting a similar activation process for granulocytes in these two diseases.

Lack of placental protein 14 production in pregnancy after frozen embryo transfer, down-regulation of anterior pituitary and administration of exogenous oestradiol and progesterone.

The circulating levels of placental protein 14 (PP14) and progesterone were measured in three pregnancies resulting from the transfer of cryopreserved embryos. Two of these women had suppressed ovarian activity as a result of pituitary down-regulation with the luteinizing hormone-releasing hormone agonist (buserelin) prior to treatment with exogenous oestradiol and progesterone. After 14 days of oral oestradiol treatment and if the endometrial thickness was greater than 7 mm, progesterone was given intramuscularly for a further 14 days with embryo transfer on the third day of this treatment. On confirmation of pregnancy by human chorionic gonadotrophin analysis, progesterone administration was altered to transvaginal pessaries for maintenance of adequate progesterone levels and endometrial support. In the two women with ovarian suppression, PP14 levels remained below the 2.5th centile of the normal range for pregnancy. In the third pregnancy, embryo transfer was performed 3 days after a spontaneous luteinizing hormone surge in a normal menstrual cycle. In this pregnancy, PP14 levels were within the normal range. Ultrasonic examination confirmed three normal ongoing singleton pregnancies. These results suggest that the majority of PP14 production in normal pregnancy is under ovarian or anterior pituitary control and that the influence of progesterone is of a secondary nature.

Molecular characterization and functional analysis of the leukocyte surface protein CD31.

The CD31 Ag is a surface glycoprotein of 130 kDa with a broad cellular distribution. We show that among peripheral human blood cells, it is expressed on monocytes, granulocytes, platelets, and a subpopulation of lymphocytes. Activation of granulocytes leads to down-regulation of CD31 molecule expression. Sequence analysis and quantitative measurements of the relatedness of the CD31 molecule to other known proteins demonstrate that it consists of six Ig constant domains and that each domain bears substantial similarity to Fc gamma R domains. We find, however, that the CD31 molecule does not bind Ig Fc domains. On human monocytes we demonstrate that CD31 mAb recognizing certain epitopes of the CD31 molecule induce the generation of reactive oxygen metabolites. No such effect was seen with human granulocytes. By using two CD31 mAb, termed 1B5 and 7E4, we analyzed the requirements for activation of the monocyte respiratory burst via CD31 Ag in more detail. We show that signal transduction occurs via formation of a CD31 Ag-mAb-Fc gamma R complex involving either Fc gamma RI (CD64) or Fc gamma RII (CDw32) molecules.