Excessive secretion of insulin precursors characterizes and predicts gestational diabetes.

Using assays that specifically measure insulin, intact proinsulin, and 32,33 split proinsulin, we examined the beta-cell secretory response to an oral glucose tolerance test (OGTT) in 64 women with gestational diabetes mellitus (GDM) and 154 pregnant normoglycemic control subjects of comparable age and body mass index. Women with GDM were characterized by a lower 30-min insulin increment (40.8 [34.9-47.6] vs. 58.6 [53.6-64] pmol insulin/mmol glucose, P < 0.001; geometric mean [95% confidence interval]) and a higher plasma insulin level at 120 min (702 [610-808] vs. 444 [400-492] pmol/l, P < 0.001). 32,33 split proinsulin levels were elevated in GDM patients in both fasting (9.1 [7.3-11.4] vs. 6.7 [6.0-7.5] pmol/l, P < 0.02) and 120-min (75.2 [62.9-90.0] vs. 52.2 [46.7-58.3] pmol/l, P < 0.001) samples, respectively. Intact proinsulin levels were significantly elevated at 120 min in the women with GDM (21.3 [18.1-25.1] vs. 14.8 [13.4-16.3] pmol/l, P < 0.001). Thus, the qualitative abnormalities of insulin secretion in GDM patients (low 30-min insulin increment, high 120-min plasma insulin, and elevated 32,33 split proinsulin) are similar to those seen in nonpregnant subjects with impaired glucose tolerance. To determine whether measures of proinsulin-like molecules (PLMs) might assist in the prediction of GDM, women who had a 1-h glucose level of > 7.7 mmol/l after a 50-g glucose challenge at 28-32 weeks' gestation had insulin and PLMs measured in the 1-h sample.(ABSTRACT TRUNCATED AT 250 WORDS)

Homozygosity for a common polymorphism in the islet-specific promoter of the glucokinase gene is associated with a reduced early insulin response to oral glucose in pregnant women.

A commonly occurring sequence variant in the islet-specific promoter of the glucokinase gene (-30 G to A) has been variably reported to be associated with reduced insulin secretory responses to oral glucose. The effect of this promoter variant may be subtle and only become apparent under conditions of beta-cell 'stress'. As late pregnancy is a time of increased insulin secretory demand, we have examined whether this common genetic variant was associated with impairment of insulin secretory responses to oral glucose in 92 women in the third trimester of pregnancy. The three women who were homozygous for the variant sequence had a markedly diminished 30' insulin incremental response to oral glucose (10.4, 11.4, and 17.2 pmol insulin mmol-1 glucose, respectively) compared to either heterozygous (49.3 (37.6-64.6 pmol insulin mmol-1 glucose)) (p < 0.002) or homozygous wild-type (51.4 (40.9-64.7 pmol insulin mmol-1 glucose)) (p < 0.002) Mann-Whitney U test) women. In a subset of 35 British Caucasian women with gestational diabetes, no mutations resulting in a change of amino acid sequence were detected by molecular scanning of all exons of the glucokinase gene. In summary, in a cohort of 35 British Caucasian women with gestational diabetes neither missense nor nonsense glucokinase mutations were found. However, in women in the third trimester of pregnancy, homozygosity for a common polymorphic variant in the islet-specific promoter of the glucokinase gene was associated with a highly significant reduction of early insulin secretory responsiveness to oral glucose. Under the conditions of increased secretory demand represented by late pregnancy, a promoter variant in the glucokinase gene may influence the early insulin secretory response to oral glucose.

Diagnosis of oesophageal cancer by detection of minichromosome maintenance 5 protein in gastric aspirates.

Symptomatic oesophageal cancer is usually advanced and the prognosis poor. Lethality of symptomatic oesophageal cancer has motivated screening for these diseases earlier in their evolution, but reliable methods for early diagnosis remain elusive. We have demonstrated that dysregulated expression of minichromosome maintenance (MCM) proteins 2-7 is characteristic of early epithelial carcinogenesis, and that these key DNA replication initiation factors can be used as diagnostic markers for cervical and genito-urinary tract cancer. In this study, we investigated whether minichromosome maintenance protein 5 (Mcm5) can be used to detect oesophageal cancer cells in gastric aspirates. Two monoclonal antibodies raised against His-tagged human Mcm5 were used in a time-resolved immunofluorometric assay to measure Mcm5 levels in cells isolated from gastric aspirates of 40 patients undergoing gastroscopy for suspected or known oesophageal carcinoma or symptoms of dyspepsia. The test discriminated with high specificity and sensitivity between patients with and without oesophageal cancer (85% sensitivity (95% confidence interval (CI)=62-97%), 85% specificity (CI=66-96%)), as demonstrated by the large area under the receiver operating characteristics curve (0.93 (95% CI=0.85-0.99)). Elevated levels of Mcm5 in gastric aspirates are highly predictive of oesophageal cancer. This simple test for oesophageal cancer is readily automated with potential applications in primary diagnosis, surveillance and screening.

Immunoassay for urothelial cancers that detects DNA replication protein Mcm5 in urine.

Cancer-screening tests for internal organs are severely constrained by low specificity or sensitivity, cost, and morbidity. We report a non-invasive immunofluorometric assay for detection of urothelial cancers based on ectopic expression of the DNA replication protein Mcm5.