Continuous Glucose Monitoring: An Opportunity for Population-Based Diabetes Management

The increasing prevalence of prediabetes and diabetes in the United States poses a serious threat to the health of the population. Closely associated with obesity, hypertension, dyslipidemia, and cardiovascular disease, a diagnosis of diabetes or prediabetes carries with it life-altering demands. Critically important among these is the requirement for frequent glucose level checks-typically performed with blood obtained from a fingerstick. Innovative real-time continuous glucose monitoring (rtCGM) technology makes it possible for patients and their clinicians to receive continuous glucose level measurements around the clock without finger sticks. Accruing evidence shows that rtCGM is an effective tool for patients and their clinicians in managing diabetes (ie, maintaining glucose levels within the recommended target range) and in understanding how lifestyle behaviors directly influence glucose levels. In recent years, a number of large payer organizations (eg, private health insurers, employers) have incorporated rtCGM in their diabetes management programs as a means of addressing the dual challenge of achieving/maintaining control of glucose levels and preventing or delaying the onset of complications. Programmatic integrated approaches have been used successfully and cost-effectively for managing other chronic conditions. Incorporating rtCGM in similar integrated approaches in diabetes management may be of value in improving quality outcomes and reducing costs on a population level. The evidence supports broader adoption and continued study to evaluate models that incorporate the use of rtCGM.

Obesity prevention in English primary schools: headteacher perspectives

Schools are seen as important contributors to obesity prevention, yet face barriers in fulfilling this function. This qualitative study investigates headteacher views on the primary school role in preventing obesity. Semi-structured interviews were held with 22 headteachers from ethnically and socio-economically diverse schools in the West Midlands, UK. Data analysis was conducted using the framework approach. Two over-arching categories were identified: 'School roles and responsibilities' and 'Influencing factors'. Participants agreed that although schools contribute towards obesity prevention in many ways, a moral responsibility to support children's holistic development was the principal motivator, rather than preventing obesity per se. The perceived impact on learning was a key driver for promoting health. Parents were believed to have the main responsibility for preventing obesity, but barriers were identified. Whilst headteachers recognized the advantageous position of schools in offering support to parents, opinion varied on the degree to which schools could and should take on this role. Headteachers serving more deprived areas reported adopting certain responsibilities that elsewhere were fulfilled by parents, and were more likely to view working with families on healthy lifestyles as an important school function. Several factors were perceived as barriers to schools doing more to prevent obesity, including academic pressure, access to expert support and space. In conclusion, school leaders need more support, through resources and government policy, to enable them to maximize their role in obesity prevention. Additionally, school-based obesity prevention should be an integral part of the education agenda rather than bolt-on initiatives.

Rural Aging in America: Proceedings of the 2017 Connectivity Summit

Rural Aging in America: Proceedings of the 2017 Connectivity Summit Alexis Skoufalos, EdD, Janice L. Clarke, RN, BBA, Dana Rose Ellis, BA, Vicki L. Shepard, MSW, MPA, and Elizabeth Y. Rula, PhD Editorial: Creating a Movement to Transform Rural Aging David B. Nash, MD, MBA, with Donato J. Tramuto, and Joseph F. Coughlin, PhD   S-3 Introduction   S-4 Summit Proceedings   S-5 Roundtable 1: The Power of Community - Enabling Social Connections and Access to Health Resources Through Community-Based Programs   S-5 Roundtable 2: Technology and Rural Health: Innovative Solutions to Bridge the Distance, Improve Care, and Deliver Programs   S-7 Roundtable 3: An Integrated Experience: The Exponential Potential of a Collaborative Approach to Rural Aging   S-8 General Discussion and Recommendations   S-8 Post-Summit Debriefing   S-9 Strategy and objectives   S-9 6-12 month action plan   S-9 Conclusion   S-9.

Sexually Transmitted Infections: Compelling Case for an Improved Screening Strategy

Sexually Transmitted Infections: Compelling Case for an Improved Screening Strategy Stephen Hull, MHS, Seán Kelley, MD, MSc, and Janice L. Clarke, RN, BBA Editorial: Sexually Transmitted Infections-A Fixable Problem: David B. Nash, MD, MBA   S-3 Introduction   S-3 Rising Prevalence of Sexually Transmitted Diseases (STIs)   S-4 Current Screening Rates for Chlamydia and Gonorrhea   S-4 The Human Toll and Economic Burden of STI-Related Illness   S-5 Current Screening Guidelines for Chlamydia and Gonorrhea   S-5 Factors Contributing to Inadequate Screening, Diagnosis, and Treatment for STIs   S-6 Methods Used to Improve Screening Rates   S-7 Benefits of Opt-Out Screening Strategies for STIs   S-8 Cost-Effectiveness of Screening for STIs   S-8 Discussion   S-9 Conclusion   S-10.

Improving Health Outcomes for Patients with Depression: A Population Health Imperative. Report on an Expert Panel Meeting

Improving Health Outcomes for Patients with Depression: A Population Health Imperative. Report on an Expert Panel Meeting Janice L. Clarke, RN, Alexis Skoufalos, EdD, Alice Medalia, PhD, and A. Mark Fendrick, MD Editorial: A Call to Action : David B. Nash, MD, MBA   S-2 OVERVIEW: Depression and the Population Health Imperative    S-3 Promoting Awareness of the Issues and Opportunities for Improvement    S-5 Cognitive Dysfunction in Affective Disorders    S-5 Critical Role of Employers in Improving Health Outcomes for Employees with Depression    S-6 Closing the Behavioral Health Professional and Process Gaps    S-6 Achieving the Triple Aim for Patients with Depressive Disorders    S-6 Improving the Experience of Care for Patients with Depression    S-6 Improving Quality of Care and Health Outcomes for Patients with Depression    S-7 Changing the Cost of Care Discussion from How Much to How Well    S-8 Panel Insights and Recommendations    S-9 Conclusion    S-10.

An Innovative Approach to Health Care Delivery for Patients with Chronic Conditions

Although the health care reform movement has brought about positive changes, lingering inefficiencies and communication gaps continue to hamper system-wide progress toward achieving the overarching goal—higher quality health care and improved population health outcomes at a lower cost. The multiple interrelated barriers to improvement are most evident in care for the population of patients with multiple chronic conditions. During transitions of care, the lack of integration among various silos and inadequate communication among providers cause delays in delivering appropriate health care services to these vulnerable patients and their caregivers, diminishing positive health outcomes and driving costs ever higher. Long-entrenched acute care-focused treatment and reimbursement paradigms hamper more effective deployment of existing resources to improve the ongoing care of these patients. New models for care coordination during transitions, longitudinal high-risk care management, and unplanned acute episodic care have been conceived and piloted with promising results. Utilizing existing resources, Mobile Integrated Healthcare is an emerging model focused on closing these care gaps by means of a round-the-clock, technologically sophisticated, physician-led interprofessional team to manage care transitions and chronic care services on-site in patients' homes or workplaces.

Testicular Microlithiasis: Is Sonographic Surveillance Necessary? Single Centre 14 Year Experience in 442 Patients with Testicular Microlithiasis

PURPOSE

Increased prevalence of germ cell tumour (GCT) is seen with testicular microlithiasis (TM) suggesting TM is a premalignant condition with US surveillance advocated. We present a cohort of patients with TM followed up in a single centre and deliberate on the value of US surveillance.

MATERIALS AND METHODS

A retrospective analysis of subjects with underlying US diagnosis of TM between 1998 and 2012. One-yearly US follow-up was offered to all patients with TM and a database maintained. Any co-existing tumour at presentation with TM was recorded. TM was divided into limited (< 5 microliths/field), classical (≥ 5 microliths/field) and florid ('snowstorm' appearance). Patient demographics, follow-up details and the development of any scrotal abnormalities were recorded. The radiological and histological findings were documented when a testicular lesion occurred during the follow-up period.

RESULTS

20 224 patients were examined: 867/20 224 (4.3 %) had TM. 21/867 (2.4 %) patients had histology proven malignant tumours at presentation. All TM patients consented to follow-up with 442/867 (51.0 %) achieving this and entering into a follow-up program (mean duration 28 months, range 8 - 165 months). Two patients developed primary GCT during the follow up period. One patient (limited TM) had undergone a previous orchiectomy for contralateral GCT and developed a palpable mass at follow up month 21. The other (limited TM) had an atrophic testis; a tumour was found on US at follow up month 62.

CONCLUSION

Two patients of 442 (0.5 %) followed up for all forms of TM in a single centre developed a GCT over a mean duration of 28 months, both had independent risk factors for the development of GCT. These findings suggest that US surveillance is not required when TM is the only abnormality in the absence of any clinical risk factors for the development of GCT.

The diagnosis of CAD in women: addressing the unmet need - a report from the national expert roundtable meeting

A multistakeholder panel comprising experts in the fields of clinical cardiology, medical technology innovation, women's health research and policy analysis, personalized medicine, payers (including self-insured employers), patient advocacy, and health economics was convened at the Heart House in Washington, DC. The following points emerged as key concepts: (1) Diagnostic challenges in the evaluation of women with symptoms suggestive of obstructive coronary artery disease (CAD) result from: (a) presentation with atypical symptoms and lower pretest probability of disease compared to men, (b) fatty tissue and breast tissue attenuation on cardiac imaging leading to false positive findings, and (c) the presence of microvascular CAD. (2) Diagnostic challenges lead to both over-testing of low-risk women and under-testing of high-risk women. (3) Efforts should be directed toward increasing clinician, clinical professional society, and consumer awareness and understanding of sex-specific differences between men and women in the pathophysiology of CAD. (4) Multiple health care stakeholders should be made aware of new advances in genomic approaches to address the challenges of diagnosing obstructive CAD; specifically, the Corus CAD gene expression test, which was shown to have high sensitivity and negative predictive value in a recent clinical trial. As such, it has promise as a tool to help clinicians to rule out obstructive CAD as a cause of a patient's symptoms. (Population Health Management 2015;18:86-92).

Conservative spine care: opportunities to improve the quality and value of care

Low back pain (LBP) has received considerable attention from researchers and health care systems because of its substantial personal, social, work-related, and economic consequences. A narrative review was conducted summarizing data about the epidemiology, care seeking, and utilization patterns for LBP in the adult US population. Recommendations from a consensus of clinical practice guidelines were compared to findings about the current state of clinical practice for LBP. The impact of the first provider consulted on the quality and value of care was analyzed longitudinally across the continuum of episodes of care. The review concludes with a description of recently published evidence that has demonstrated that favorable health and economic outcomes can be achieved by incorporating evidence-informed decision criteria and guidance about entry into conservative low back care pathways.

Improving awareness of best practices to reduce surgical site infection: a multistakeholder approach

Surgical site infection (SSI) is recognized as a focus area by the Centers for Medicare and Medicaid Services, the Joint Commission, the Institute for Healthcare Improvement, and the Institute of Medicine. An estimated 47% to 84% of SSIs present after discharge from the hospital or ambulatory care facility and, as a result, go undetected by standard SSI surveillance programs. Evidence-based processes and practices that are known to reduce the incidence of SSIs tend to be underused in routine practice. This article describes a multistakeholder process used to develop an educational initiative to raise awareness of best practices to reduce SSIs. The goal was to create a patient-centric educational initiative that involved an active partnership among all stakeholders-medical professional organizations, hospitals/health systems, health insurers, employers and other purchasers, and consumers/patients-to provide the climate necessary to create and sustain a culture of safety.

Leptomeningeal metastases in the MRI era

BACKGROUND

Diagnosis of leptomeningeal metastasis (LM) has become increasingly frequent. The diagnostic gold standard has been CSF cytology, but MRI is now used routinely for diagnosis. Diagnosis and prognosis of LM has not been studied in the MRI era.

METHODS

Patients with LM from 2002 through 2004 were identified through a neurology database, as well as by reviewing all abnormal CSF cytologies from a pathology database. Diagnosis was made by malignant cytology or imaging; suspicious cases treated as LM were also included.

RESULTS

A total of 187 patients with LM were analyzed in this retrospective review. Of these, 150 had solid and 37 had hematopoietic malignancies. Median age was 56.4 years, and median Karnofsky performance status (KPS) was 70. The most common types of solid tumor were breast (65 patients), lung (47), gastrointestinal (11), and melanoma (9). Of the hematopoietic tumors, 21 were lymphoma and 15 were leukemia. Fifty-three percent of patients were diagnosed by imaging, 23% by cytology, and 24% by both. Treatment included radiation therapy in 55%, intrathecal chemotherapy in 29%, and systemic chemotherapy in 18%; 21% received supportive care alone. Median overall survival was 2.4 (95% confidence interval 1.9-3.1) months. Median survival for patients with hematopoietic tumors was 4.7 months and for solid tumors was 2.3 months (p = 0.0006). In multivariate analysis, initial KPS and tumor type (solid vs hematopoietic) were significant predictors of survival.

CONCLUSIONS

Despite enhanced diagnosis with MRI, prognosis remains poor in leptomeningeal metastasis. Those with hematopoietic tumors continue to fare better than those with solid tumors.

Opportunity, resources, and affordability: multistakeholder perspectives

On two occasions last year, the Jefferson School of Population Health convened a National Advisory Board of scientists and opinion leaders from key stakeholder groups at a high-level forum to explore different perspectives and to discuss improving access for patients who require treatment with biologic drugs. The following is the first of two articles documenting these discussions. The second article will appear in a subsequent issue of Biotechnology Healthcare.

A focused telephonic nursing intervention delivers improved adherence to A1c testing

Compliance with hemoglobin A1c (A1c) testing is suboptimal despite the clear national recommendations and guidelines established for care of patients with diabetes. Recent studies have demonstrated a relationship between participation in a diabetes disease management (DM) program and improved adherence to A1c testing. A focused intervention study was initiated to investigate the ability of a DM program to drive improvement in A1c testing. A cohort of 36,327 members experienced a statistically significant increase (29%) in A1c testing while participating in the 6-month focused intervention. This finding demonstrated that a focused DM intervention is able to deliver improvement in a clinical process metric critical for managing patients with diabetes, thereby reducing their risk of disease exacerbation.

Intratesticular haematoma: differentiation from tumour on clinical history and ultrasound appearances in two cases

Intratesticular haematoma is not well described in the ultrasound literature and may be mistaken for a primary testicular malignancy if a detailed clinical history and careful ultrasound examination are not performed. We report two cases of intratesticular haematoma (one complicated by the presence of microlithiasis), describe the ultrasound appearances and document the natural history of the haematomas. A clinical history coupled with Doppler ultrasound features is crucial for conservative management.

Association between frequency of telephonic contact and clinical testing for a large, geographically diverse diabetes disease management population

Diabetes disease management (DM) programs strive to promote healthy behaviors, including obtaining hemoglobin A1c (A1c) and low-density lipoprotein (LDL) tests as part of standards of care. The purpose of this study was to examine the relationship between frequency of telephonic contact and A1c and LDL testing rates. A total of 245,668 members continuously enrolled in diabetes DM programs were evaluated for performance of an A1c or LDL test during their first 12 months in the programs. The association between the number of calls a member received and clinical testing rates was examined. Members who received four calls demonstrated a 24.1% and 21.5% relative increase in A1c and LDL testing rates, respectively, compared to members who received DM mailings alone. Response to the telephonic intervention as part of the diabetes DM programs was influenced by member characteristics including gender, age, and disease burden. For example, females who received four calls achieved a 27.7% and 23.6% increase in A1c and LDL testing, respectively, compared to females who received mailings alone; by comparison, males who were called achieved 21.2% and 19.9% relative increase in A1c and LDL testing, respectively, compared to those who received mailings alone. This study demonstrates a positive association between frequency of telephonic contact and increased performance of an A1c or LDL test in a large, diverse diabetes population participating in DM programs. The impact of member characteristics on the responsiveness to these programs provides DM program designers with knowledge for developing strategies to promote healthy behaviors and improve diabetes outcomes.

Improving quality by encouraging providers to use pediatric combination vaccines

In the last 4 decades, the number of diseases that vaccines can prevent has quadrupled, and, correspondingly, so has the number of immunizations that is to be administered before a child's second birthday. Based on current recommendations, a child may receive as many as six vaccine injections in a single visit. Vaccine technology has advanced significantly since the introduction of the first combination vaccine, diphtheria-tetanus (DT), in the 1950s. In the United States today, as many as five antigens can be administered in a single injection, and additional combination vaccines are in the pipeline. Increasing the number of antigens delivered with a single injection minimizes physical discomfort for the child, reduces associated stress for the parent, saves time for the provider, and is likely to improve vaccine coverage and timeliness of administration rates. While national immunization guidelines from the Centers for Disease Control and Prevention call for use of combination vaccines where available, provider and parent perceptions can act as barriers to their optimal use. Managed care organizations (MCOs) have the opportunity to improve quality of care and immunization rates by educating providers on the use of combination vaccines in accordance with the national guidelines. This article examines the evidence for pediatric combination vaccines, discusses barriers to their use among parents and providers, presents quality and cost implications of a managed care policy to broaden their use, and suggests ways in which MCOs can more actively promote appropriate use of combination vaccines by providers.

Disease management

What follows is a comprehensive discussion of chronic diseases and how they can be managed in the workplace. General background about chronic diseases is given, as well as a description of what kinds of programs are available, how they can be implemented, how they can be assessed, and potential cost savings and projected return on investment. Also included is a brief summary of accreditation and certification processes currently in place.

Scrotal calcification: ultrasound appearances, distribution and aetiology

This pictorial review illustrates the ultrasound appearances of scrotal calcification, distinguishing between intratesticular and extratesticular calcification. Intratesticular calcification may be due to phleboliths, spermatic granulomas or vascular calcification, or it may occur in association with tumours. Extratesticular calcification is more frequently encountered and is usually related to previous inflammatory disease of the epididymis. Testicular microlithiasis, a rare condition characterized by multiple scattered echogenic foci within the testis, is produced by the formation of microliths from degenerating cells in the seminiferous tubules. Testicular microlithiasis has been demonstrated as an incidental finding as well as in association with both benign and malignant tumours of the testis.

Glucose-6-phosphate dehydrogenase-6-phosphogluconolactonase. A novel bifunctional enzyme in malaria parasites

Plasmodium falciparum glucose 6-phosphate dehydrogenase (Pf Glc6PD), compared to other Glc6PDs has an additional 300 amino acids at the N-terminus. They are not related to Glc6PD but are similar to a family of proteins (devb) of unknown function, some of which are encoded next to Glc6PD in certain bacteria. The human devb homologue has recently been shown to have 6-phosphogluconolactonase (6PGL) activity. This suggests Pf Glc6PD may be a bifunctional enzyme, the evolution of which has involved the fusion of adjacent genes. Further functional analysis of Pf Glc6PD has been hampered because parts of the gene could not be cloned. We have isolated and sequenced the corresponding Plasmodium berghei gene and shown it encodes an enzyme (Pb Glc6PD) with the same structure as the P. falciparum enzyme. Pb Glc6PD is 950 amino acids long with significant sequence similarity in both the devb and Glc6PD domains with the P. falciparum enzyme. The P. berghei enzyme does not have an asparagine-rich segment between the N and C halves and it contains an insertion at the same point in the Glc6PD region as the P. falciparum enzyme but the insertion in the P. berghei is longer (110 versus 62 amino acids) and unrelated in sequence to the P. falciparum insertion. Though expression of this enzyme in bacteria produced largely insoluble protein, conditions were found where the full-length enzyme was produced in a soluble form which was purified via a histidine tag. We show that this enzyme has both Glc6PD and 6PGL activities. Thus the first two steps of the pentose phosphate pathway are catalysed by a single novel bifunctional enzyme in these parasites.

The Genetic Regulation of Fucosylated and Sialylated Antigens on Developing Myeloid Cells

The first part of this article reviews the stages of normal development of haemopoietic cells committed to the myeloid lineage, properties of leukaemic cell lines that are arrested at specific maturation stages along the granulocytic pathway, the structures of carbohydrate antigenic markers that appear on myeloid cell surfaces, with especial reference to sialyl-Le(x) (NeuAcalpha2-3Galbeta1-4[Fucalpha1-3]GlcNAc), and the role of this antigen on mature granulocytes as a ligand for selectin molecules. The families of fucosyl- and sialyltransferase genes encoding enzymes responsible for the biosynthesis of sialyl-Le(x), and the pathways leading to the formation of this antigen, and more complex related structures, are described. The second part of the article outlines the work carried out in the authors' laboratory with leukaemic cell lines in an attempt to ascertain the biochemical and genetic basis of the lowering of sialyl-Le(x) expression that occurs at intermediate stages of normal haemopoietic development. Analysis of enzyme levels and mRNA expression of the fucosyl- and sialyltransferase genes has led to the conclusion that depletion of substrate resulting from high levels of enzyme activity from co-expressed genes FUT4 and ST6Gal1 probably accounts for the dip in expression of sialyl-Le(x), rather than a change in the level of expression of FUT7, the gene in myeloid cells encoding the enzyme ultimately responsible for the synthesis of sialyl-Le(x). The possible significance of this change in relation to normal cell maturation is discussed.

A randomised crossover trial of chemotherapy in the home: patient preferences and cost analysis

OBJECTIVES

To determine patient preferences and cost differences between home-based and hospital-based chemotherapy.

DESIGN

Randomised crossover trial.

SETTING

A tertiary cancer hospital in Melbourne, Victoria.

PARTICIPANTS

20 patients who required chemotherapy suitable for administration at home.

INTERVENTIONS

Patients were assigned at random to receive their first chemotherapy treatment in either the home or the hospital and the second treatment in the alternative setting.

MAIN OUTCOME MEASURES

Patient preference, costs.

RESULTS

There was universal agreement by the 20 patients in the randomised trial that home-based chemotherapy was the preferred option (P < 0.0001). No problems were nominated by the patients as being associated with home-based chemotherapy. Home-based treatment was estimated to result in an increased cost of $83 (P = 0.0002) for each chemotherapy treatment compared with hospital-based treatment. Reported advantages for chemotherapy in the home included the elimination of travel, reduction in treatment-associated anxiety, reduction in the burden on carers and family, and the ability to continue other duties. There were no significant complications associated with administration of chemotherapy in the home.

CONCLUSIONS

Patients prefer home-based chemotherapy to hospital-based treatment. The future of chemotherapy-in-the-home programs in Australia will depend on whether patient preferences are deemed to offset any potential increase in costs.

Meckel's diverticulitis in an elderly man diagnosed by computed tomography

Meckel's diverticulum is the most common congenital abnormality of the gastrointestinal tract. Complications most frequently arise in children younger than 2 years who present with gastrointestinal bleeding. The diagnosis is usually made via radionuclide scintigraphy or intraoperatively. The authors report a 71-year-old man who developed a sudden onset of right lower quadrant abdominal pain, without bleeding, and was diagnosed as having Meckel's diverticulitis via computed tomography. The presence of Meckel' s diverticulitis was confirmed at surgery. Complications of a Meckel's diverticulum must be considered at any age. Computed tomography is another modality that may be helpful in the preoperative diagnosis.

Expression of human alpha-l-fucosyltransferase gene homologs in monkey kidney COS cells and modification of potential fucosyltransferase acceptor substrates by an endogenous glycosidase

Previous investigations on the monkey kidney COS cell line demonstrated the weak expression of fucosylated cell surface antigens and presence of endogenous fucosyltransferase activities in cell extracts. RT-PCR analyses have now revealed expression of five homologs of human fucosyltransferase genes, FUT1, FUT4, FUT5, FUT7, and FUT8, in COS cell mRNA. The enzyme in COS cell extracts acting on unsialylated Type 2 structures is closely similar in its properties to the alpha1,3-fucosyltransferase encoded by human FUT4 gene and does not resemble the product of the FUT5 gene. Although FUT1 is expressed in the COS cell mRNA, it has not been possible to demonstrate alpha1,2-fucosyltransferase activity in cell extracts but the presence of Le(y) and blood-group A antigenic determinants on the cell surface imply the formation of H-precursor structures at some stage. The most strongly expressed fucosyltransferase in the COS cells is the alpha1,6-enzyme transferring fucose to the innermost N -acetylglucosamine unit in N -glycan chains; this enzyme is similar in its properties to the product of the human FUT8 gene. The enzymes resembling the human FUT4 and FUT8 gene products both had pH optima of 7.0 and were resistant to 10 mM NEM. The incorporation of fucose into asialo-fetuin was optimal at 5.5 and was inhibited by 10 mM NEM. This result initially suggested the presence of a third fucosyltransferase expressed in the COS cells but we have now shown that triantennary N- glycans with terminal nonreducing galactose units, similar to those present in asialo-fetuin, are modified by a weak endogenous beta-galactosidase in the COS cell extracts and thereby rendered suitable substrates for the alpha1,6-fucosyltransferase.

Independent regulation of Fuc-TIV and Fuc-TVII genes leading to modulation of cell surface antigen expression in developing myeloid cells

Fucosylated antigen expression, fucosyltransferase activities and expression of Fuc-TIV and Fuc-TVII genes have been measured in the human leukemic cell lines KG1a, arrested at the undifferentiated myeloblast stage of maturation and KG1, arrested at the myeloblast and early promyelocytic stage. The results are compared with those we earlier found for the later promyelocytic cell line HL-60 and the myelocyte form into which HL-60 cells can be induced to differentiate. These leukemic cell lines, and the differentiated HL-60 cells, are believed to correspond to four successive stages of myeloid maturation in the bone marrow. Fuc-TVII mRNA was strongly expressed in the myeloblastic KG1a cells but expression was less in KG1 and HL-60 cells. In contrast to the sharp fall in Fuc-TIV expression observed on differentiation of HL-60 cells, the expression of Fuc-TIV mRNA showed a progressive increase from KG1a to HL-60 cells; thus the peak of expression of this gene was at the HL-60 promyelocyte stage. This peak correlated with an increase in fucosyltransferase activity with nonsialylated acceptors and the transitory downregulation of cell surface sialyl-Le(x) expression and upregulation of Le(x), VIM-2 and Le(y) expression. The variations in levels of expression of the fucosylated antigens on the surface of the developing myeloid cells therefore correlate with variations in mRNA expression arising from the independent regulation of Fuc-TIV and Fuc-TVII genes.

Three different endogenous alpha-L-fucosyltransferases expressed in COS cells

The monkey kidney COS cell line is frequently used for the transient expression of cloned human fucosyltransferase cDNAs in the belief that negligible endogenous expression of fucosyltransferase genes occurs in these cells. In the course of transfection experiments we observed weak cell surface expression of sialyl-Lex and weak fucosyltransferase activity in extracts of control untransfected cells. Since these activities could complicate interpretation of the results with the transfected genes, a more detailed examination was undertaken that has now revealed expression of three different fucosyltransferases in the cells. One enzyme, which utilises N-acetyllactosamine as substrate, has a pH optimum of 7.0, is resistant to heat inactivation, and has been tentatively identified as an alpha1,3-fucosyltransferase. A second enzyme which acts on asialo-fetuin has a pH optimum of 5.5 and is rapidly inactivated by heat; the acceptor sugar and positional linkage of the transferred fucose are not yet established. A third enzyme that utilises asialo-agalacto-fetuin as acceptor is provisionally identified as an alpha1,6-fucosyltransferase.