CD antigens 2001

The most recent Human Leucocyte Differentiation Antigen Workshop ("HLDA7") took place in 2000 in Harrogate, UK and the proceedings are about to be published (Leucocyte Typing VII). New Sections were introduced in this Workship (Dendritic cells, Stem/progenitor cells, Erythroid cells and Carbohydrate Structures) and monoclonal antibodies were selected for which at least some molecular data were already available (to avoid "blind" screening of reagents against known specificities). A total of more than 80 new CD specificities were established (previously the average was less than 30 new CD specificities per Workshop) and these are listed in this article. There is already evidence for the existence of many new leucocyte surface molecules for study at the next HLDA Workshop (in Adelaide in 2004), and we have listed in this article a number of such potential CD candidates (identified following the production of monoclonal antibodies or via gene cloning). There are also today an increasing number of lineage- and/or stage-restricted leucocyte-associated molecules localised within the cell cytoplasm (or nucleus): they will certainly prove of intense in the future for many laboratories studying human haematopoietic cells (regardless of whether a new "intracellular CD" categorisation scheme is devised for such molecules).

Use of insulin pumps in pregnancies complicated by type 2 diabetes and gestational diabetes in a multiethnic community

OBJECTIVE

To describe the use of insulin pump therapy in women with gestational diabetes mellitus (GDM) or type 2 diabetes in pregnancy and persistent hyperglycemia despite multiple injections of subcutaneous insulin.

RESEARCH DESIGN AND METHODS

As part of a service audit, deliveries to women with diabetes at a single South Auckland hospital were reviewed from 1991 through 1994. Glycemic control was estimated by the mean of self-recorded and laboratory postprandial glucose concentrations. In a nested case-control study, pregnancies complicated by GDM/type 2 diabetes with use of an insulin pump were compared with those without insulin pump therapy and peak insulin requirements of 100-199 units/ day, matched for ethnicity and type of diabetes.

RESULTS

A total of 30 of 251 Polynesian, European, and South Asian women with singleton pregnancies complicated by insulin-requiring GDM/type 2 diabetes used an insulin pump. An additional two women with high insulin requirements discontinued pump therapy. None of the women with GDM/type 2 diabetes experienced severe hypoglycemia, whereas 79% of the women had improved glycemic control within 1-4 weeks. Mothers using a pump had greater insulin requirements (median maximum 246 vs. 130 units per day) and greater weight gain (10.6 vs. 5.0 kg). Their babies were more likely to be admitted to the Special Care Baby Unit but were neither significantly heavier nor experienced greater hypoglycemia than control subjects.

CONCLUSIONS

Insulin pump therapy seems to be safe and effective for maintaining glycemic control in pregnancies complicated by GDM/type 2 diabetes and requiring large doses of insulin.

CD antigens 2001

This paper reviews the Seventh Human Leucocyte Differentiation Antigen (HLDA7) workshop. Due to the limitations of "blind" antibody screening, which had been evident at the previous meeting in 1996, participants at HLDA7 adopted a more selective approach to the choice of antibodies by identifying new CD specificities. This resulted in the addition of more than 80 new CD specificities. Plans for the eighth and subsequent workshops are also previewed.

Cloning, characterization, and tissue expression pattern of mouse Nma/BAMBI during odontogenesis

Degenerate oligonucleotides to consensus serine kinase functional domains previously identified a novel, partial rabbit tooth cDNA (Zeichner-David et al., 1992) that was used in this study to identify a full-length mouse clone. A 1390-base-pair cDNA clone was isolated encoding a putative 260-amino-acid open reading frame containing a hydrophobic 25-amino-acid potential transmembrane domain. This clone shares some homology with the TGF-beta type I receptor family, but lacks the intracellular kinase domain. DNA database analysis revealed that this clone has 86% identity to a newly isolated human gene termed non-metastatic gene A and 80% identity to a Xenopus cDNA clone termed BMP and activin membrane bound inhibitor. Here we report the mouse Nma/BAMBI cDNA sequence, the tissue expression pattern, and confirmed expression in dental cell lines. This study demonstrates that Nma/BAMBI is a highly conserved protein across species and is expressed at high levels during odontogenesis.

Rural training and the state of rural health services: effect of rural background on the perception and attitude of first-year medical students at the university of melbourne

The aim of this project is to investigate the relationship between medical students' background and their perception of the state of rural health services; willingness to undertake internship training or work as a doctor in a rural hospital; expected benefits and disadvantages of training or working as a doctor in a rural hospital; and factors interfering with acceptance of a job as a doctor in rural areas. A questionnaire-based survey was distributed to 100 first-year medical students attending the Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne at the end of semester 1. The response rate was 97%, including 44 males and 53 females. A strong relationship was found between rural background and an intention to undertake internship training in a rural hospital (86% of students from a rural background expressed this desire vs 30% of students from an urban background). Furthermore, all students from a rural background expressed a desire to work as a doctor in a rural hospital after completing postgraduate training. Compared to urban students, students from a rural background showed a more positive attitude towards health services in rural areas including public hospitals ( P = 0.02), private general practice ( P = 0.004), ambulance service ( P = 0.0002) and baby health centres ( P = 0.005). Citizenship or gender was not significantly related to the perception of any of these services. The ranking of factors interfering with acceptance of a job as a doctor in rural areas were different for rural and urban students. Students from rural backgrounds reported spouse/partner needs (76% vs 49%, P = 0.038) and school availability for children (59% vs 30%, P = 0.023) as barriers more frequently than urban students, respectively). On the other hand, urban students rated the following factors higher: personal factors (76% vs 53%, respectively), education opportunities (56% vs 24%), social/cultural facilities (50% vs 41%) and the need for frequent travel (29% vs 12%). None of these interfering factors were significantly different. Urban students were more likely than rural students to report that their views were a result of adverse media reports. In conclusion, students from a rural background were more willing to be trained or to work as doctors in rural areas. This was associated with a greater adverse influence by the media upon students.

Heart disease and diabetes risk factors in Pacific Islands communities and associations with measures of body fat

AIMS

To describe the prevalence of obesity and other coronary heart disease and Type 2 diabetes risk factors by age and ethnic group in Pacific Island communities and to determine the associations between these risk factors and body mass index.

METHODS

Cross-sectional data from commuity-based intervention projects were combined to provide anthropometric, blood sample and blood pressure data on 1,175 Pacific Islands people (467 men, 708 women) aged 20 years and over from church communities in South, Central and West Auckland. Self-reported data on diabetes status and leisure-time physical activity were also collected.

RESULTS

Based on an ethnic-specific mass index (BMI) cut-off (> 32 kg/m2), 45% of men and 66% of women were obese. The age-standardised prevalence of known diabetes was 12%. Men and women aged 40-60 years had the highest risk factor levels and were the most sedentary. Tongans had higher risk factor levels than Samoans. In men, BMI and waist circumference were associated (p<0.05), in the direction of greater disease risk, with blood pressure and concentrations of total cholesterol, HDL-cholesterol, LDL-cholesterol, triglycerides, and blood glucose. In women, these associations were similar but less consistent.

CONCLUSIONS

While these data are not representative for all Pacific people living in New Zealand, they do show an extremely high prevalence of obesity and significant associations between obesity and other cardiovascular risk factors. These communities warrant a very high priority as part of public health efforts to address New Zealand's growing obesity epidemic.

Effectiveness of changes in the delivery of diabetes care in a rural community

Diabetes has a significant impact upon health in rural Maori communities. A diabetes club was established to support self-care and improve diabetes management in a rural community in Northland, New Zealand. A structured approach to care and an associated audit were also introduced. Patient involvement and ownership of the condition were considered important issues. Monitoring of care processes increased by 79%. The first year of audit was associated with a reduction in mean fructosamine from 369 +/- 85 micromol L-1 to 321 +/- 65 micromol L-1 and this was sustained for a further 3 years. The number of people using insulin increased from 15 to 22%. The audit process facilitated the implementation of changes in the delivery of care. We conclude that the data indicate that the enthusiastic delivery of care in general practice, with a devolution of power to the patient, linked to an audit service can result in improved management among patients with Type 2 diabetes.

Diabetes in general practice: Tongans in Tonga and South Auckland

The aim of this study was to compare the management and treatment outcomes of Tongan diabetic patients in Tonga and South Auckland, New Zealand. This was achieved by comparison of Tongan diabetic patients within clinical audits from a general practice in Tonga (n = 124) with those from participating general practices in South Auckland (n = 168). Our results indicate that some measures of diabetes care and outcomes were similar or even better in Tonga, while some interventions were not available in Tonga. Control of weight, glucose, blood pressure and cholesterol remained difficult in both areas. Severe diabetic foot damage was more common among Tongan patients in Tonga (6.5% vs 1.8%, P < 0.05). This international comparison shows that Tongans in both Tonga and New Zealand remain at high-risk of complications independent of the health system under which care is being delivered. While barriers to implementation may differ in the two settings, improvements in the co-ordination of care are likely to be of benefit in both settings.

Polynesians: prone to obesity and Type 2 diabetes mellitus but not hyperinsulinaemia

AIMS

To compare the extent of hyperinsulinaemia among New Zealand Europeans and Polynesians (an ethnic group at high risk of Type 2 diabetes mellitus).

METHODS

A cross-sectional survey from randomly selected households was conducted in inner urban South Auckland. Subjects were either European, Maori or Pacific Islands Polynesians aged 40-79 years and were screened for diabetes using a random blood glucose. Those with an elevated result, and 20% randomly selected from those with a normal screening result, were invited to a 75-g glucose tolerance test. WHO criteria (1998) for diabetes were used.

RESULTS

In those aged 40-59 years, total prevalence of diabetes was 7.5 (6.2-9.0)% in Europeans but 21.1 (16.6-25.6)% among Maori and 25.0 (19.8-30.1)% among Pacific peoples; obesity (body mass index >or= 31.0 kg/m2) was present in 26% Europeans, 63% Maori and 69% Pacific peoples. Non-diabetic Polynesians were relatively hyperglycaemic and hyperinsulinaemic. After adjusting for the degree of obesity, Polynesians had similar insulin levels to Europeans.

CONCLUSIONS

These findings indicate that Polynesians are not intrinsically insulin resistant as a group, a prerequisite found in most other ethnic groups at high risk of Type 2 diabetes mellitus. The high prevalence of Type 2 diabetes in Polynesians could be the result of their high prevalence of obesity.

Developmental regulation of dentin sialophosphoprotein during ameloblast differentiation: a potential enamel matrix nucleator

The two major dentin matrix proteins, dentin sialoprotein and dentin phosphoprotein have been shown to be expressed as a single large transcript termed dentin sialophosphoprotein (DSPP). These non-collagenous matrix proteins, identified biochemically by their unique physical-chemical properties, are specific cleavage products of a large parent acidic phosphorylated protein (pI 4.0). Previous studies have shown expression of dentin sialoprotein at the protein level by ameloblasts. The purpose of this study was to determine the temporal-spatial pattern of DSPP expression during amelogenesis. In situ hybridization and immunohistochemistry were performed on sections of developing mouse molars. These data were correlated with RT-PCR analysis of in vitro enamel organ epithelium monolayer cell cultures enriched for ameloblasts. Our data indicates initial expression of the DSPP transcripts and protein during early ameloblast differentiation prior to the secretory phase when the majority of the enamel matrix is formed. Ameloblasts appear to tightly down-regulate DSPP transcription as enamel matrix formation is up-regulated. These data demonstrate DSPP expression during amelogenesis is under highly controlled developmental regulation. Therefore, DSPP may have a primary role in the initial mineralization events of both enamel and dentin, acting as a potential nucleator of hydroxyapatite crystal formation.

Identification and characterization of a cDNA for mouse ameloblastin

Ameloblastin was first identified as one of the most abundant novel transcripts from a random screening of a rat incisor cDNA library. In situ hybridization experiments have shown ameloblastin expression to be specific to ameloblasts, with highest levels in secretory and maturation stage ameloblasts and cells of the epithelial root sheath. Ameloblastin has been identified as a candidate gene for the local hypoplastic form of autosomal dominant amelogenesis imperfecta, by virtue of it's location within the critical disease locus. The purpose of this study was to isolate a full length mouse ameloblastin cDNA and determine its temporal expression pattern during odontogenesis. A newborn mouse molar cDNA library was screened using a rat ameloblastin cDNA probe. Positive clones were confirmed by PCR analysis with ameloblastin-specific primers, and their size determined with vector-specific primers. Phage clones were rescued to phagemid using Exassist helper phage and the nucleotide sequence determined. We report here the identification of two clones, exhibiting alternative splicing of the putative open reading frame, and use of multiple polyadenylation signals. Nucleotide sequence analysis indicated a high degree of similarity to rat ameloblastin, rat amelin 1 and 2 and porcine sheathlin. Reverse transcriptase-PCR analysis using mouse first and second mandibular molar mRNA indicated initial expression at E-14. This is one day after the initial expression of tuftelin (E-13) and one day prior to that of amelogenin (E-15).

Human ameloblastin gene: genomic organization and mutation analysis in amelogenesis imperfecta patients

A gene encoding the enamel protein ameloblastin (AMBN) was recently localized to a region on chromosome 4q21 containing a gene for the inherited enamel defect local hypoplastic amelogenesis imperfecta (AIH2). Ameloblastin protein is located at the Tomes processes of secretory ameloblasts and in the sheath space between rod-interrod enamel, and the AMBN gene therefore represents a viable candidate gene for local hypoplastic amelogenesis imperfecta (AI). In this study, the genomic organization of human AMBN was characterized. The gene was shown to consist of 13 exons and 12 introns. An alternatively spliced 45 bp sequence was shown not to represent a separate exon and is most likely spliced by the use of a cryptic splice site. The finding that there were no recombinations between an intragenic microsatellite and AIH2 encouraged us to evaluate this gene's potential role as a candidate gene for local hypoplastic AI. Mutation screening was performed on all 13 exons in 20 families and 8 sporadic cases with 6 different forms of AI. DNA variants were found but none that was associated exclusively with local hypoplastic AI or any of the other variants of AI in the identified Swedish families. This study excludes the coding regions and the splice sites of AMBN from a causative role in the pathogenesis of AIH2.

A community diabetes educator course for the unemployed in South Auckland, New Zealand

PURPOSE

This paper describes an education program that targeted long-term unemployed people from the community and trained them to work as diabetes educators in their own communities in an attempt to address issues of cultural appropriateness.

METHODS

Government funding was obtained to conduct two 22-week training courses for people who had been selected by their communities. These courses built on participants' existing cultural skills and provided appropriate diabetes training.

RESULTS

The results indicate that the courses were successful both in creating a cadre of culturally acceptable diabetes educators and providing employment for course participants.

CONCLUSIONS

Previously unemployed lay people are able to provide diabetes education in the primary prevention and group settings. Such individuals are able to incorporate extensive cultural skills in their work.

Predisposition to nephropathy in Polynesians is associated with family history of renal disease, not diabetes mellitus

AIMS

Familial clustering of diabetes and nephropathy suggests that either common environmental or inherited mechanisms are important in developing diabetic nephropathy. If an inherited mechanism is important, the albumin excretion rate might be increased in those at future risk. This study aimed to determine whether people with a family history of diabetes or people with a family history of renal disease were most at risk.

METHODS

In a two-by-two factorial study of urinary albumin in non-diabetic Polynesians, 90 people with a first degree relative (FDR) with end-stage renal failure (ESRF) and diabetes (group 1) were compared with 90 people with a FDR with non-diabetic ESRF (group 2), with 90 people with a FDR with diabetes but no known nephropathy (group 3) and 90 people with no known relatives with either diabetes or nephropathy (group 4). Groups were matched for ethnicity and age.

RESULTS

Subjects with a family history of ESRF (groups 1 and 2) had an increased mean albumin-creatinine ratio (1.25 vs. 1.00 mg/mmol, P = 0.01), but in subjects with a family history of diabetes (groups 1 and 3), the mean ratios were not significantly different from those without a family history of diabetes (1.06 vs. 1.17 mg/mmol; P = 0.2). In those with a family history of nephropathy, fasting blood glucose and systolic blood pressure were increased, while fasting insulin and 2 h insulin concentrations were lower. A family history of diabetes was associated with an increased fasting blood glucose and 2-h blood glucose. By multiple linear regression, the mean systolic blood pressure (P = 0.02), the 2-h glucose concentration (P = 0.05), a family history of renal failure (P = 0.04), female sex (P = 0.0001) and the total cholesterol (P = 0.01) were each independently associated with microalbuminuria, while a family history of diabetes was not (P = 0.09).

CONCLUSIONS

These data suggest that among Polynesians there is no specific inherited tendency to diabetic nephropathy per se. The risk of nephropathy does not appear to be associated with the degree of familial risk of diabetes itself. Rather, the risk of diabetic nephropathy may be the result of a familial risk of nephropathy from any cause and is associated with diabetes through relative hypoinsulinaemia and hyperglycaemia.