Identification of Vancomycin Resistance in Methicillin-resistant Staphylococcus aureus in two macaque species and decolonization and long-term prevention of recolonization in Cynomolgus Macaques (Macaca fascicularis)

Methicillin-resistant Staphylococcus aureus (MRSA) is a S. aureus strain with resistance to beta-lactam antibiotics, making it a global human and veterinary health concern. Specifically, immunosuppressed patients have a remarkably higher risk of clinical MRSA infections with significantly increased rates of prolonged clinical recovery, morbidity, and mortality. The current treatment of choice for MRSA is vancomycin. Importantly, we report the first known vancomycin-resistant S. aureus (VRSA) carriers in a cohort of Mauritian cynomolgus macaques (CM) imported to the Oregon National Primate Research Center (ONPRC), with a MRSA carrier rate of 76.9% (10/13 animals). All MRSA isolates also demonstrated resistance to vancomycin with prevalence of vancomycin-intermediate Staphylococcus aureus (VISA) at 30% (3/10 MRSA-positive CMs) and VRSA at 70% (7/10 MRSA-positive CMs). Additionally, we identified VRSA in a rhesus macaque (RM) housed within the same room as the VRSA-positive CMs and identified a MRSA/VISA carrier rate of 18.8% in RMs (3/16 positive for both MRSA and VISA) in unexposed recently assigned animals directly from the ONPRC RM breeding colony. Considering that the MRSA and VRSA/VISA-positive CMs future study aims included significant immunosuppression, MRSA/VRSA/VISA decolonization treatment and expanded "MRSA-free" practices were employed to maintain this status. We report the first controlled study using in-depth analyses with appropriate diagnostic serial testing to definitively show an MRSA decolonization therapy (90% success rate) and expanded barrier practice techniques to successfully prevent recolonization (100%) of a cohort of CMs MRSA-free (up to 529 days with a total of 4,806 MRSA-free NHP days).

Allogeneic immunity clears latent virus following allogeneic stem cell transplantation in SIV-infected ART-suppressed macaques

Allogeneic hematopoietic stem cell transplantation (alloHSCT) from donors lacking C-C chemokine receptor 5 (CCR5Δ32/Δ32) can cure HIV, yet mechanisms remain speculative. To define how alloHSCT mediates HIV cure, we performed MHC-matched alloHSCT in SIV+, anti-retroviral therapy (ART)-suppressed Mauritian cynomolgus macaques (MCMs) and demonstrated that allogeneic immunity was the major driver of reservoir clearance, occurring first in peripheral blood, then peripheral lymph nodes, and finally in mesenteric lymph nodes draining the gastrointestinal tract. While allogeneic immunity could extirpate the latent viral reservoir and did so in two alloHSCT-recipient MCMs that remained aviremic >2.5 years after stopping ART, in other cases, it was insufficient without protection of engrafting cells afforded by CCR5-deficiency, as CCR5-tropic virus spread to donor CD4+ T cells despite full ART suppression. These data demonstrate the individual contributions of allogeneic immunity and CCR5 deficiency to HIV cure and support defining targets of alloimmunity for curative strategies independent of HSCT.

Correction: Mitigation of endemic GI-tract pathogen-mediated inflammation through development of multimodal treatment regimen and its impact on SIV acquisition in rhesus macaques

[This corrects the article DOI: 10.1371/journal.ppat.1009565.].

Terumo spectra optia leukapheresis of cynomolgus macaques for hematopoietic stem cell and T cell collection

Macaques are physiologically relevant animal models of human immunology and infectious disease that have provided key insights and advanced clinical treatment in transplantation, vaccinology, and HIV/AIDS. However, the small size of macaques is a stumbling block for studies requiring large numbers of cells, such as hematopoietic stem cells (HSCs) for transplantation, antigen-specific lymphocytes for in-depth immunological analysis, and latently-infected CD4+ T-cells for HIV cure studies. Here, we provide a detailed protocol for collection of large numbers of HSCs and T-cells from cynomolgus macaques as small as 3 kg using the Terumo Spectra Optia apheresis system, yielding an average of 5.0 × 10⁹ total nucleated cells from mobilized animals and 1.2 × 10⁹ total nucleated cells from nonmobilized animals per procedure. This report provides sufficient detail to adapt this apheresis technique at other institutions, which will facilitate more efficient and detailed analysis of HSCs and their progeny blood cells.

Viral opportunistic infections in Mauritian cynomolgus macaques undergoing allogeneic stem cell transplantation mirror human transplant infectious disease complications

Allogeneic hematopoietic stem cell transplantation (HSCT) and xenotransplantation are accompanied by viral reactivations and virus-associated complications resulting from immune deficiency. Here, in a Mauritian cynomolgus macaque model of fully MHC-matched allogeneic HSCT, we report reactivations of cynomolgus polyomavirus, lymphocryptovirus, and cytomegalovirus, macaque viruses analogous to HSCT-associated human counterparts BK virus, Epstein-Barr virus, and human cytomegalovirus. Viral replication in recipient macaques resulted in characteristic disease manifestations observed in HSCT patients, such as polyomavirus-associated hemorrhagic cystitis and tubulointerstitial nephritis or lymphocryptovirus-associated post-transplant lymphoproliferative disorder. However, in most cases, the reconstituted immune system, alone or in combination with short-term pharmacological intervention, exerted control over viral replication, suggesting engraftment of functional donor-derived immunity. Indeed, the donor-derived reconstituted immune systems of two long-term engrafted HSCT recipient macaques responded to live attenuated yellow fever 17D vaccine (YFV 17D) indistinguishably from untransplanted controls, mounting 17D-targeted neutralizing antibody responses and clearing YFV 17D within 14 days. Together, these data demonstrate that this macaque model of allogeneic HSCT recapitulates clinical situations of opportunistic viral infections in transplant patients and provides a pre-clinical model to test novel prophylactic and therapeutic modalities.

Understanding biofilm in practice: a global survey of health professionals

OBJECTIVE

The aim of this survey was to examine health professionals' views and practices relating to biofilm in chronic wounds.

METHOD

A global online survey was conducted to assess the current understanding of biofilm and wound management practices. The survey consisted of 20 questions designed to evaluate health professional knowledge of biofilm, perception and understanding of biofilm behaviour, detection and diagnosis, and treatment. Respondents were classified as 'specialists' if wounds were their primary focus and they developed protocols and determined formularies. Respondents were classified as 'generalists' if wounds were part of multiple indications they treat and they were able to choose wound care products from a restricted list of products. The Pearson's chi-square or Fisher's exact test was used to assess whether the responses were independent of the clinician role, health-care setting and country.

RESULTS

Overall, 3011 health professionals took part in the survey, of which 397 were excluded or disqualified. Of the remaining 2614 respondents, 1223 (46.8%) completed the entire survey. Although the majority of health professionals were aware of biofilm, knowledge gaps regarding its prevalence in chronic wounds were evident. In general, the majority indicated that they understood that biofilm is detrimental to wound healing. With the exception of wound stalling, there was a lack of consensus on other clinical signs in the detection and diagnosis of biofilm. Knowledge gaps were also evident over the treatment of biofilm and the efficacy of antimicrobial treatments, debridement and wound dressing.

CONCLUSION

Our results show that though there is a broad recognition of biofilm and its possible role in chronic wounds, there is still a need to educate and increase knowledge on recognition and treatment of biofilm.

Allogeneic stem cell transplantation in fully MHC-matched Mauritian cynomolgus macaques recapitulates diverse human clinical outcomes

Allogeneic hematopoietic stem cell transplantation (HSCT) is a critically important therapy for hematological malignancies, inborn errors of metabolism, and immunodeficiency disorders, yet complications such as graft-vs.-host disease (GvHD) limit survival. Development of anti-GvHD therapies that do not adversely affect susceptibility to infection or graft-vs.-tumor immunity are hampered by the lack of a physiologically relevant, preclinical model of allogeneic HSCT. Here we show a spectrum of diverse clinical HSCT outcomes including primary and secondary graft failure, lethal GvHD, and stable, disease-free full donor engraftment using reduced intensity conditioning and mobilized peripheral blood HSCT in unrelated, fully MHC-matched Mauritian-origin cynomolgus macaques. Anti-GvHD prophylaxis of tacrolimus, post-transplant cyclophosphamide, and CD28 blockade induces multi-lineage, full donor chimerism and recipient-specific tolerance while maintaining pathogen-specific immunity. These results establish a new preclinical allogeneic HSCT model for evaluation of GvHD prophylaxis and next-generation HSCT-mediated therapies for solid organ tolerance, cure of non-malignant hematological disease, and HIV reservoir clearance.

Rhesus macaques are not ideal for studying response to allogeneic hematopoietic stem cell transplant (allo-HSCT) owing to complex MHC genetics that prevent full MHC-matching. Here the authors show that inbred Mauritian-origin cynomolgus macaques are a superior preclinical model of allogeneic stem cell transplantation that mimics diverse clinical outcomes of human allo-HSCT.

Zika Virus infection of rhesus macaques leads to viral persistence in multiple tissues

Zika virus (ZIKV), an emerging flavivirus, has recently spread explosively through the Western hemisphere. In addition to symptoms including fever, rash, arthralgia, and conjunctivitis, ZIKV infection of pregnant women can cause microcephaly and other developmental abnormalities in the fetus. We report herein the results of ZIKV infection of adult rhesus macaques. Following subcutaneous infection, animals developed transient plasma viremia and viruria from 1-7 days post infection (dpi) that was accompanied by the development of a rash, fever and conjunctivitis. Animals produced a robust adaptive immune response to ZIKV, although systemic cytokine response was minimal. At 7 dpi, virus was detected in peripheral nervous tissue, multiple lymphoid tissues, joints, and the uterus of the necropsied animals. Notably, viral RNA persisted in neuronal, lymphoid and joint/muscle tissues and the male and female reproductive tissues through 28 to 35 dpi. The tropism and persistence of ZIKV in the peripheral nerves and reproductive tract may provide a mechanism of subsequent neuropathogenesis and sexual transmission.

B cell follicle sanctuary permits persistent productive simian immunodeficiency virus infection in elite controllers

Chronic-phase HIV and simian immunodeficiency virus (SIV) replication is reduced by as much as 10,000-fold in elite controllers (ECs) compared with typical progressors (TPs), but sufficient viral replication persists in EC tissues to allow viral sequence evolution and induce excess immune activation. Here we show that productive SIV infection in rhesus monkey ECs, but not TPs, is markedly restricted to CD4(+) follicular helper T (TFH) cells, suggesting that these EC monkeys' highly effective SIV-specific CD8(+) T cells can effectively clear productive SIV infection from extrafollicular sites, but their relative exclusion from B cell follicles prevents their elimination of productively infected TFH cells. CD8(+) lymphocyte depletion in EC monkeys resulted in a dramatic re-distribution of productive SIV infection to non-TFH cells, with restriction of productive infection to TFH cells resuming upon CD8(+) T cell recovery. Thus, B cell follicles constitute 'sanctuaries' for persistent SIV replication in the presence of potent anti-viral CD8(+) T cell responses, potentially complicating efforts to cure HIV infection with therapeutic vaccination or T cell immunotherapy.

Does NSCLC patient-rated performance status predict survival more accurately than physician ratings?

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Background: The Eastern Cooperative Oncology Group (ECOG) score is a well known predictor of survival, which impacts on treatment decisions. Patient (pt) rated activity level, using the Patient Generated Subjective Global Assessment (PG-SGA) scale, is identical in criteria to the ECOG scale used by physicians. We compared the patient rated activity level (Pt-PS) to physician rated PS (MD-PS), at baseline, and evaluated survival with respect to the 2 PS ratings. Methods: Pts with newly diagnosed advanced NSCLC (stages 3–4) completed a PG-SGA self rated questionnaire, which was then compared to the physician-generated ECOG score recorded prior to any treatment using a Wilcoxon signed rank test. Pts were treated with standard chemotherapy. Survival analysis was performed using a Kaplan Meier analysis and Cox regression. Results: 92 pts (M: F-48:44) with a mean age of 65 years (39–83) were included. 67 (73%) presented with stage 4 disease. 62 (67%) had an MD-PS of 0–1, whereas only 51 (55%) had a Pt-PS of 0 -1. MD-PS 3–4 was seen in 9 (10%), compared to 28 (30%) by Pt-PS. Pt-PS was significantly different from MD-PS in 48% of scores (p=0.003). When scores were not congruent, 29/44 (66%) pts evaluated themselves as having a worse PS than the physician. Survival analysis demonstrated that stage and functional status irrespective of method of reporting was predictive of survival (p=0.01 for MD-PS and p=0.001 for Pt-PS). However, when comparing median survival by method of performance status evaluation, Pt-PS was associated with superior stratification of survival than MD-PS ( table 1 ). Conclusions: Pt-PS and MD-PS are not congruent almost 50% of the time. Pt-PS allows for better stratification of survival and should be further evaluated in prospective trials.

No significant financial relationships to disclose.

[Table: see text]

Quality of life and survival in patients receiving chemotherapy for advanced non-small cell lung cancer (NSCLC)

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Background: Quality of life (QoL) is an important endpoint measure in clinical cancer trials. We evaluated prospectively the effects of two cycles of chemotherapy (CT) on QoL and the relationship between QoL and survival in advanced NSCLC patients (pts). Methods: The short-form of the SF36 was completed prior to and after 2 cycles of chemotherapy. An ITT analysis was used; a score of 0 was assigned to those who died and the last observation was carried forward for those with missing data. Results: Fifty-nine pts consented to participate and pre-chemo evaluation was available for 58 pts. Of these 58, only 40 pts completed the study (4 died, 14 did not complete the post evaluation). There were 26M: 32F with a median age of 61±11 years. Fifty pts (86%) were stage 3B (pl. eff)/4 and 50pts (86%) were PS 0–1. Overall QoL decreased significantly from 100±19 to 91±36 after two cycles of chemotherapy (p=0.03). This decline was attributed to a significant decrease in the physical health subscale (p=0.001), with 36% of pts reporting a clinically significant decline of =2. No change in the mental health subscale was observed. The symptoms that had the most profound negative impact on the physical health subscale were: ‘easily get sick’ (54%), ‘increased pain’ (30%) and ‘decreased activities’ (27%). SD+PR occurred in 36 (62%) pts, whereas 22 (38%) pts had PD after two cycles of chemotherapy. No correlation was found between response to chemo and change in QoL. The median survival (15±6.8mo), of pts whose QoL score remained stable or improved (n=36) was significantly better than those (n=22) whose QoL decreased (9±3.2 mo) (p=0.01). Conclusions: QoL decreased following chemotherapy due to a decrease in the physical health subscale. Further studies are required to determine if training can improve physical health and thus QoL and survival.

No significant financial relationships to disclose.

Physiological correlates of cancer-related fatigue in advanced non-small cell lung cancer (NSCLC) patients

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Background: Fatigue is a debilitating consequence of lung cancer and its treatments. The etiology of fatigue is unclear, and our current knowledge does not point to logical interventions. In this study, global fatigue score was assessed using the Brief Fatigue Inventory (BFI). A symptom questionnaire, as well as muscular and cardiorespiratory function, were assessed as potential contributors to the global fatigue score. Methods: Participants were evaluated by a physical therapist within the McGill Cancer Nutrition and Rehabilitation Program. Performance-based measures of physical function [upper limb strength and endurance (Jamar dynamometry), lower limb strength (30sec chair rise), cardiorespiratory function (2 minute walk -2MW)] and a symptom questionnaire [Edmonton Symptom Assessment Scale (ESAS)] were conducted at one point in time. Results: Eighty patients (43M:37F, mean age 68 ± 12 ) participated in the study. Forty-seven percent were actively receiving treatment at the time of assessment. On the BFI, 56% had moderate or severe fatigue and 88% indicated fatigue had interfered with their functioning during the past 24 hours. Global fatigue scores were unrelated to hand grip strength or endurance measurements but were significantly correlated with chair rise performance (R= -0.31, p<0.05), 2MW (R= -0.31, p<0.05), ESAS rating of pain (R=0.47, p<0.01), overall ESAS rating of breathlessness (R= 0.59, p<0.01), and ESAS rating of strength (R=0.58, p<0.01). Multivariate regression analysis suggested the best model for global fatigue scores incorporates chair rise performance, 2MW performance, ESAS rating of strength and ESAS rating of shortness of breath (adjusted R sq = 0.68, p<0.01). Conclusions: Fatigue is prevalent and impacts on the function of advanced NSCLC patients. Several key factors contribute to this fatigue, with muscular and cardiorespiratory restrictions playing an important role. Such findings may have clinical implications in the recommendations of rest and exercise to best manage fatigue.

No significant financial relationships to disclose.

Improving prevention systems in primary care practices: the Health Education and Research Trial (HEART)

BACKGROUND

The Health Education and Research Trial (HEART) was a multicenter clinical trial designed to test methods to improve primary care practice systems for heart disease prevention services. We present the trial methodology, the practices' use of medical record tools, and changes in documentation of cardiovascular risk factor screening and management.

METHODS

Primary care practices were recruited from 4 Midwestern states. The factorial design resulted in 4 study groups: conference only, conference and quality improvement consultations, conference and prevention coordinator, and all interventions combined. Medical record audits and physician, staff, and patient surveys assessed practice change in cardiovascular disease risk factor documentation.

RESULTS

Practices participated fully in this project, set goals to improve preventive services, and implemented recommended medical record tools. The number of goals set and the increase in the use of medical record tools were greatest in the combined intervention group, with improvements noted in all groups. The use of patient history questionnaires, problem lists, and flow sheets was significantly higher in the combined intervention group when compared with the conference-only group. Documentation of risk factor screening in a recommended-medical record location improved in all intervention groups, with significant sustained improvements in the practices that received the combined intervention. Documented risk factor management significantly improved in all intervention groups compared with the conference-only control.

CONCLUSION

Primary care practices are interested in improving prevention systems and can change these systems in response to supportive external interventions. Promoting organizational change to produce sustained improvement in preventive service clinical outcomes is a complex process that requires further research.

Tools to improve documentation of smoking status. Continuous quality improvement and electronic medical records

BACKGROUND

Despite the deleterious effects of smoking on the nation's health and evidence that smoking cessation advice by family practice physicians is cost-effective, self-sustaining office systems to identify smokers in primary care clinics have been difficult to establish. We worked on a continuous quality improvement project group, aided by an electronic medical record, to design a system to document and periodically update smoking status in a consistent place in the medical record.

INTERVENTION

Using the continuous quality improvement plan-do-study-act cycle, a 7-member group worked with nursing staff to define roles, routines and responsibilities for medical assistants to screen for and document 1 of 4 categories of smoking status in the major problem list of the electronic medical record for at least 80% of patient appointments. Screening rate was tracked monthly by means of the electronic medical record and feedback was given to staff.

RESULTS

The screening rate rose from 18.4% to 80.3% within 2 weeks after the system was implemented and was maintained for 19 months. An additional benefit was an increased rate of smoking cessation counseling documented by providers, from a baseline rate of 17.1% to 48.3%.

CONCLUSIONS

A continuous quality improvement group process aided by an electronic medical record is useful to develop a self-sustaining office system to screen, document, and periodically update smoking status in a consistent place in the medical record. Although screening for and documenting smoking status are only the first step toward helping patients stop smoking, it is an important one.

Carbon-13 isotope effect studies of Trypanosoma brucei ornithine decarboxylase

Carbon isotope effect studies were undertaken with the wild-type pyridoxal 5'-phosphate (PLP)-dependent enzyme ornithine decarboxylase (ODC) from Trypanosoma brucei and with several active site mutants of the enzyme. For the decarboxylation of the optimal substrate, L-ornithine, by wild-type ODC, the observed carbon isotope effect (k12/k13) is 1.033 at pH 7.3. In comparison to the expected intrinsic isotope effect (k12/k13 = 1.06) for decarboxylation, this value suggests that both the rate of decarboxylation and the rate of Schiff base interchange with L-ornithine are partially rate-limiting for the reaction steps up to decarboxylation. In contrast, with the alternate substrate L-Lys, which shows lower catalytic efficiency, the carbon isotope effect increased to 1.063, demonstrating that decarboxylation has become the rate-limiting step. For the mutant enzymes, E274A ODC and C360A ODC, with L-ornithine as substrate the carbon isotope effect also approaches the intrinsic limit. Glu-274 was previously demonstrated to play a direct role in carbanion stabilization, and thus the large carbon isotope effect (k12/k13 = 1.055) is consistent with an impaired rate of decarboxylation compared to wild-type ODC. In contrast, for K69A ODC, the isotope effect is almost entirely suppressed, suggesting that Schiff-base formation (which now must occur from enzyme-bound PLP, rather than from an enzyme-bound PLP-Schiff base) has become rate-determining.

The delicate balance of law and ethics: a model for health administration educators

The purpose of this paper is to provide a model for educators involved in teaching interrelated ethical, moral and legal dilemmas confronting health care delivery. For purposes of discussion, the AIDS epidemic is used as an example. Similarly complex issues, such as invitro fertilization, transplantation policy, etc. could also be analyzed using this model. A review of federal law, including a number of relevant cases, and their relationship of fundamental ethics issues is provided.

Recent implementations of electronic medical records in four family practice residency programs

Electronic medical records (EMRs) are increasingly replacing paper records, and many residency program directors are interested in incorporating EMR systems into their clinics. The authors describe their experiences implementing EMRs in their family practice residency programs; the four programs are the Eau Claire Family Practice Residency Program, the Galveston Family Practice Residency Program, the Mayo-Scottsdale Residency Program, and the Wyoming Valley Family Practice Residency. The authors provide background information about each program and an overview of the EMR systems; they then describe the implementation processes, addressing training, integration with other software- and paper-based systems, security, costs, and effects on patient volume and staffing levels. Finally, they discuss the general benefits of and barriers to EMR-system implementations, and make recommendations for other programs considering implementing EMRs.

Is LEEP a feasible addition to the family physician's office?

BACKGROUND

Seven thousand women die annually from cervical cancer in the US. This disease is preventable if cervical dysplasia is treated. Loop Electrosurgical Excision of the Cervix (LEEP) is a new treatment for dysplasia. This study evaluates the acceptability and feasibility of having LEEP available in a family physician's office.

METHOD

We performed a retrospective audit of colposcopy patients at 2 family practice clinics over a 2-year period. We determined the patients who met criteria for LEEP, surveyed the patients and calculated the cost benefit to the clinic.

RESULT

Out of 288 patients undergoing colposcopy, 40 (14%) were candidates for LEEP. Few complications, minimal discomfort, and performance of the procedure at their primary clinic were important to patients. Patient cost for LEEP in the office is $700 compared to $1450 in the hospital. Nine LEEP procedures per year provides a break-even point for the clinic.

CONCLUSION

LEEP offers the advantage over laser treatment of lower cost, use of local anesthesia, and provision of a pathology specimen. Performing LEEP in the family physician's office is cost effective and meets patient needs.

Pseudometabolic acidosis caused by underfill of Vacutainer tubes

STUDY OBJECTIVES

To determine how serum bicarbonate and anion gap are affected by sample size in a 10-mL red-top (clot) Vacutainer tube at the fixed sample volumes of 10, 3, and 1 mL.

DESIGN

Venous phlebotomy on consecutive emergency department patients; three tubes drawn in random order. The first 20 patients had unvented tubes, and the last ten had the tubes vented within one minute of the draw.

SETTING

University hospital ED.

PARTICIPANTS

Thirty ED patients.

INTERVENTIONS

All blood samples had electrolytes determined within one hour of phlebotomy. To approximate the ED setting, the time to analysis was not controlled, but each triple draw had simultaneous analysis.

MEASUREMENTS AND MAIN RESULTS

Mean bicarbonate in mmol/L (with sample size) was 21.7 (10 mL), 19.4 (3 mL), and 16.3 (1 mL) (r2 = .86, P = .0001). Anion gap in mmol/L was 16.7 (10 mL), 17.5 (3 mL), and 19.1 (1 mL) (r2 = .84, P = .0077). Venting of Vacutainer tubes did not significantly change these results.

CONCLUSION

Underfill of 10-mL Vacutainer tubes causes a significant decline in bicarbonate and an increase in anion gap that may be mistaken for a metabolic acidosis. To correct for these effects, the bicarbonate should be increased by 0.5 to 0.6 mmol/L, and the anion gap should be decreased by 0.2 to 0.3 mmol/L for every milliliter of air above the sample in a 10-mL Vacutainer tube. Venting the tubes will not correct this effect. All tubes should be filled completely to avoid creating a pseudometabolic acidosis.

Serum bicarbonate declines with sample size in vacutainer tubes

Serum bicarbonate testing has been reported to be inaccurate in several clinical studies. This prompted a search for systemic errors in bicarbonate testing devices, which has been inconclusive. The effect on serum bicarbonate level measurement of partially filling plain red-top (clot) vacutainer tubes was studied in healthy volunteers. First, 10-mL vacutainers were filled with 9.5 mL, 6 mL, 3 mL, and 1 mL of identical blood. Second, pediatric (3 mL) vacutainers were filled with 3 mL, 1 mL, and 0.5 mL of identical blood. The serum bicarbonate level was measured on an automated stat analyzer. Linear regression with dummy variables for subjects showed a significant reduction in bicarbonate reading as volume in the vacutainer decreased. Consistent decrease was noted regardless of whether samples were analyzed immediately after clotting (10 minutes) or at 20, 30, and 40 minutes after withdrawal of blood. This decrease was evident regardless of whether blood was aspirated directly into a vacutainer or first aspirated into a syringe and injected into a vacutainer. Underfilling of vacutainers may account for low bicarbonate readings and thus vacutainers should be filled completely to obtain accurate measurements of serum bicarbonate levels.

Exclusion of an exon in monocyte alpha-1-antitrypsin mRNA after stimulation of U937 cells by interleukin-6

Monocytes potentially express two mRNA species by alternative splicing of exons at the 5' end of the gene. During inflammation the plasma concentration of AAT can increase about three-fold. In a myelomonocytic cell line (U937), under basal conditions, two AAT mRNA species are produced. After stimulation by interleukin-6 (IL-6) one mRNA species is produced resulting from the exclusion of the second monocyte exon. These findings demonstrate a novel way in which the expression of mRNA can be modified in a single cell type.

Dental caries in permanent teeth in children of migrant farm workers

A 1984 study of dental disease in 534 children (aged 6-15) of migrant farm workers in Colorado found that the prevalence of disease for this population continues to exceed the national and regional average. The mean DMFS was 3.56 with only 23 per cent caries free compared to a regional non-migrant DMFS mean of 2.50 with 44.7 per cent caries free. Results indicate that the children of migrant farm workers should remain a priority in preventive and restorative dental care programs.