Crustacean color-change hormone: amino acid sequence and chemical synthesis.

The blanching hormone of the prawn, Pandalus borealis, is pGlu-Leu-Asn-Phe-Ser-Pro-Gly-Trp-NH(2). Its structure was settled by a combination of mass spectrometry and Edman-dansyl analysis of a thermolysin fragment. Confirmation of the structure was obtained by chemical synthesis from amino acids. This neurosecreted hormone is active in picogram amounts when tested in shrimps.

Structure of a light-adapting hormone from the shrimp, Pandalus borealis.

The structure of a light-adapting hormone of the shrimp, Pandalus borealis, has been determined. The hormone, which had been isolated from Pandalus eyestalks and which adapts the shrimp to brighter light conditions by causing the pigment in the distal retinal pigment cells of the eye to move into a more proximal position, is the peptide: Asn-Ser-Gly-Met-Ile-Asn-Ser-Ile-Leu-Gly-Ile-Pro-Arg-Val-Met-Thr-Glu-Ala-NH2. The structure was obtained by sequence analysis by the dansyl-Edman method of the intact hormone and of isolated tryptic and thermolytic peptides.

Islet cell antibodies at diagnosis, but not leanness, relate to a better cardiovascular risk factor profile 5 years after diagnosis of NIDDM.

OBJECTIVE: To evaluate the relationship between islet cell antibodies (ICAs) and the cardiovascular risk profile 5 years after clinical diagnosis of NIDDM. RESEARCH DESIGN AND METHODS: Five years after clinical diagnosis, we evaluated blood pressure (BP) and lipids in 17 NIDDM patients with ICA at diagnosis (age 60 +/- 4 years) and 133 NIDDM patients without ICA at diagnosis (age 61 +/- 1 year). Urinary albumin excretion was evaluated in a subset of 12 NIDDM patients with ICA at diagnosis (age 60 +/- 4 years) and 82 NIDDM patients without ICA at diagnosis (age 61 +/- 1 year). RESULTS: NIDDM patients without ICA showed higher BP (140/86 +/- 2/1 mmHg vs. 128/79 +/- 3/2 mmHg; P < 0.05), total cholesterol (6.10 +/- 0.11 vs. 5.09 +/- 0.29 mmol/l; P < 0.01), LDL-to-HDL ratio (3.85 +/- 0.14 vs. 2.49 +/- 0.18; P < 0.001), and triglycerides (2.58 +/- 0.24 vs. 0.90 +/- 0.06 mmol/l; P < 0.001), lower HDL cholesterol (1.08 +/- 0.03 vs. 1.40 +/- 0.08 mmol/l; P < 0.001), and higher urinary albumin excretion (0.16 +/- 0.06 vs. 0.01 +/- 0.01 g/24 h; P < 0.05) than NIDDM patients with ICA. Among NIDDM patients without ICA, no differences concerning BP or lipids were found between obese and nonobese patients. CONCLUSIONS: ICA at diagnosis of NIDDM is a marker of more favorable cardiovascular risk profile 5 years after clinical diagnosis.

Gender, autoantibodies, and obesity in newly diagnosed diabetic patients aged 40-75 years.

OBJECTIVE: To evaluate the frequency of autoimmune markers (islet cell antibodies (ICA] and glutamic acid decarboxylase antibodies [GADA]) and clinical features in newly diagnosed people with diabetes aged 40-75 years. RESEARCH DESIGN AND METHODS: Two hundred fifty-nine consecutive patients (aged 40-75 years) with newly suspected diabetes diagnosed during a 2-year period were studied. The diagnosis of newly discovered diabetes was confirmed in 203 patients. Gender, BMI, HbA1c, fasting C-peptide, ICA, and GADA were evaluated. The frequency of obesity was estimated using two different sets of criteria: 1) National Diabetes Data Group (NDDG) criteria, and 2) criteria based on a Swedish reference population. RESULTS: The annual incidence of diabetes was 106 per 100,000 people. The incidence of diabetes in those patients who were 40-54 years old was significantly higher in men than in women (odds ratio: 2.16; P = 0.001). ICA were detected in 16 of 203 patients (8%), whereas 17 of 203 patients (8%) were GADA+; 10 of 203 (5%) patients were positive for both ICA and GADA. Among the 203 diabetic patients, 19 (9.4%) were classified as having IDDM, giving an IDDM incidence of 10 per 100,000 people aged 40-75 years. The frequency of obesity in NIDDM was high but varied with its definition; the frequency of obesity was highest (P < 0.001) when NDDG criteria, and not Swedish reference values, were used (57 of 75 [76%] vs. 40 of 75 [53%] for women and 66 of 109 [61%] vs. 45 of 109 [41%] for men). CONCLUSIONS: A striking male preponderance was found among incident cases of diabetes in people aged 40-54 years. Autoimmune markers were detected in 10% of incident cases of diabetes in people aged 40-75 years. Using a conservative estimation, as many as 10 of 100,000 middle-aged and elderly subjects developed IDDM. The frequency of obesity in NIDDM was high but this was also the case in the reference population.

Beta-cell function in relation to islet cell antibodies during the first 3 yr after clinical diagnosis of diabetes in type II diabetic patients.

OBJECTIVE: To determine the effects of islet cell antibodies on beta-cell function during the first 3 yr after diagnosis in type II diabetic patients. RESEARCH DESIGN AND METHODS: beta-cell function in type II diabetic patients with (n = 11, 50 +/- 5 yr of age) and without (n = 10, 52 +/- 4 yr of age) ICA was followed prospectively and compared with beta-cell function in type I adult diabetic patients (n = 17, 37 +/- 5 yr of age) and in healthy control subjects (n = 34, age 45 +/- 3 yr). beta-cell function was evaluated as fasting C-peptide, 1 + 3 min C-peptide after intravenous glucose, and delta C-peptide after glucagon. RESULTS: Fasting C-peptide was equal in type II diabetic patients with ICA (0.30 +/- 0.03 nM) and type I diabetic patients (0.24 +/- 0.03 nM) at diagnosis, and decreased (P < 0.05) during 3 yr in these groups but not in type II diabetic patients without ICA. At diagnosis, type II diabetic patients with ICA showed a 1 + 3 min C-peptide (0.92 +/- 0.17 nM) lower (P < 0.001) than control subjects but higher (P < 0.05) than type I diabetic patients (0.53 +/- 0.11 nM). After 1 yr, 1 + 3 min C-peptide in type II diabetic patients with ICA had decreased (P < 0.05) to 0.18 +/- 0.11 nM and was equal to type I diabetic patients (0.38 +/- 0.10 nM). delta C-peptide after glucagon was equally impaired in type II diabetic patients with ICA (0.38 +/- 0.06 nM) and type I diabetic patients (0.35 +/- 0.11 nM) at diagnosis. After 3 yr, type II diabetic patients with ICA had fasting C-peptide of 0.09 +/- 0.04 nM, 1 + 3 min C-peptide of 0.18 +/- 0.10 nM, and delta C-peptide after glucagon of 0.20 +/- 0.09 nM, values equal to type I diabetic patients but lower (P < 0.01) than in type II diabetic patients without ICA, whose values remained unchanged; fasting C-peptide of 0.97 +/- 0.17 nM, 1 + 3 min C-peptide of 2.31 +/- 0.50 nM, and delta C-peptide after glucagon of 1.76 +/- 0.28 nM. CONCLUSIONS: In patients considered type II diabetic with ICA, beta-cell function progressively decreased after diagnosis, and after 3 yr was similar to type I diabetic patients, whereas beta-cell function in type II diabetic patients without ICA was unchanged.

Progression of retinopathy after improved metabolic control in type 2 diabetic patients. Relation to IGF-1 and hemostatic variables.

OBJECTIVE: To determine the impact of improved glycemic control on the development and progression of retinopathy after the institution of insulin therapy in patients with type 2 diabetes and to assess the relation to IGF-1 and hemostatic variables. RESEARCH DESIGN AND METHODS: In a prospective observational study, 45 type 2 diabetic patients were examined at baseline and 1, 3, 6, 12, and 24 months after change to insulin therapy. Retinopathy was graded on fundus photographs using the Wisconsin scale; HbA1c, IGF-1, and hemostatic variables were measured. RESULTS: During the observation period of 2 years, 23 patients progressed in the retinopathy scale; 8 progressed > or = 3 levels. After 2 years of insulin treatment, HbA1c and IGF-1 were significantly lower than at baseline, whereas the hemostatic variables had not changed significantly. Progression of retinopathy > or = 3 levels was related to the degree of HbA1c reduction, the duration of diabetes, a higher prothrombin fragment 1 + 2 levels (F1 + 2), but not to other hemostatic variables or IGF-1. The relative risk for progression > or = 3 levels was 2.6 when HbA1c had been reduced > or = 3 percent units (95% CI 1.1-6.1). CONCLUSIONS: The magnitude of improvement of HbA1c by the institution of insulin treatment over a 2-year period may be associated with progression of retinopathy in patients with type 2 diabetes.

High levels of antigen-specific islet antibodies predict future beta-cell failure in patients with onset of diabetes in adult age.

It is unclear whether high levels of antigen-specific islet antibodies [GADA (glutamic acid decarboxylase 65 antibodies) and IA2-ab (protein tyrosine phosphatase-like protein antibodies)] predict beta-cell failure in patients with onset of diabetes in adult age. Therefore, GADA and IA2-ab levels at the diagnosis of diabetes were related to fasting plasma C-peptide levels 5 yr later in 148 patients with diabetes onset in adult age (age at onset, 20-77 yr; median, 57 yr). Classical islet cell antibodies (ICA) were also determined. Complete beta-cell failure (undetectable fasting plasma C-peptide) was only present in 4 patients at diagnosis of diabetes, but in 21 patients 5 yr thereafter. At diagnosis, ICA were detected in 20 of 21 (95%) patients with beta-cell failure after 5 yr and in only 7 of 127 (5%) without, whereas GADA and/or IA2-ab (>97.5 percentile of healthy controls) were detected in all 21 (100%) with but also in 23 of 127 (18%) patients without beta-cell failure after 5 yr. Thus, ICA had a higher positive predictive value (74%) than GADA and/or IA2-ab (47%; P < 0.05). With high cutoff values for GADA and IA2-ab, however, GADA and/or IA2-ab were detected in 19 of 21 (90%) patients with beta-cell failure vs. only in 5 of 127 (4%) without, giving a positive predictive value of 79%. Slightly elevated GADA levels in IA2-ab-negative patients were associated with progressive but not complete beta-cell failure within the study period. Hence, high GADA and/or IA2-ab levels predict a future complete beta-cell failure, whereas low GADA levels predict slowly progressive beta-cell insufficiency.

Beta-hydroxyaspartic acid in vitamin K-dependent plasma proteins from scorbutic and warfarin-treated guinea pigs.

beta- Hydroxyaspartic acid is a rare amino acid, present in all vitamin K-dependent plasma proteins except prothrombin, and is formed by a post-translational hydroxylation of aspartic acid. We have now investigated whether this hydroxylation, like that of proline in collagen, is vitamin C-dependent. The vitamin K-dependent plasma proteins were isolated from normal and scorbutic guinea pig plasma by barium citrate adsorption and the beta- hydroxyaspartic acid content was determined. Compared with normal animals, scorbutic animals showed no significant reduction of beta- hydroxyaspartic acid content. In warfarin-treated animals there was a decreased content of both beta- hydroxyaspartic acid and gamma-carboxyglutamic acid in the barium citrate adsorbed fraction. It was concluded that the post-translational hydroxylation of aspartic acid is unlikely to be vitamin C-dependent.

erythro-beta-Hydroxyaspartic acid in bovine factor IX and factor X.

To localize beta-hydroxyaspartic acid in factor IX and factor X the two proteins were cleaved with cyanogen bromide and trypsin, respectively. Peptides containing beta-hydroxyaspartic acid were isolated and subjected to Edman degradation. The phenylthiohydantoin derivative of beta-hydroxyaspartic acid was identified by HPLC in position 3 in the factor IX fragment and in position 1 in the factor X fragment. This corresponds to position 64 in factor IX and position 63 in the light chain of factor X. The assignments were confirmed by subtractive Edman degradation and with the dansyl method.

A cDNA coding for human sex hormone binding globulin. Homology to vitamin K-dependent protein S.

Affinity purified antibodies to human sex hormone binding globulin (SHBG) were used in screening a human liver cDNA library, constructed in the expression vector lambda gt11. One clone, identified as producing recombinant SHBG, carried a cDNA insert of 1.1 kb. The nucleotide sequence of the insert had an open reading frame coding for 356 amino acid residues. The coding sequence was followed by a short 3'-region of 19 non-translated nucleotides and a poly(A) tail. Confirmation that the cDNA clone represented human SHBG was obtained by the finding of a complete agreement in amino acid sequence with several peptide fragments generated from purified SHBG by proteolytic cleavage. The primary structure of SHBG shows a considerable homology to that of protein S, a vitamin K-dependent protein with functions in the coagulation system.

The genes for SHBG/ABP and the SHBG-like region of vitamin K-dependent protein S have evolved from a common ancestral gene.

Sex hormone binding globulin (SHBG) is the most important sex steroid transport protein in human plasma. It is the product of the same single gene as the androgen binding protein (ABP) of testis. Protein S is another protein, which is an important cofactor in the anticoagulation system and, as far as is known today, functionally unrelated to SHBG/ABP. Protein S also has a role in the complement system. A comparison of the human genes for SHBG/ABP and protein S reveals a sequence similarity, which is of a low grade only, between the SHBG/ABP protein and a similar sized COOH-terminal domain of protein S. However, the intron-exon organization exhibits a striking similarity in the two genes, illustrating evolutionary events leading to the appearance of two functionally different proteins from common ancestral genetic elements.

gamma-Carboxyglutamic acid in human urine.

gamma-Carboxyglutamic acid, the amino acid responsible for the vitamin K dependent, Ca2+-binding structures of some of the blood coagulation proteins, has been identified in human urine. The amino acid wasisolated and its identity was proved by comparing it with synthetic gamma-carboxyglutamic acid by electrophoretic and chromatographic methods and by mass spectrometry. The isolated compound was also converted to glutamic acid by heat decarboxylation, a reaction consistent with its anticipated structure. A method for the quantitation of free gamma-carboxyglutamic acid in human urine was developed. The method consisted of an anion-exchange concentration step followed by automatic amino acid analysis using a pH 2.0 lithium citrate buffer. In three non-fasting adult males the urinary excretion of gamma-carboxyglutamic acid ranged between 27 and 42 mumol/24 h and in six non-fasting adult females it ranged between 19 and 32 mumol/24 h. One fasting adult male excreted 36 mumol/24 h.

Islet autoantibodies in the prediction of diabetes in school children.

In 1987 serum was collected from 1031 non-diabetic schoolchildren in the Southeast area of Sweden with the aim of evaluating islet autoantibody status (ICA, GADA and IA2-ab) in the prediction of diabetes in schoolchildren. The clinical development of Type 1 diabetes in the children was assessed in 1994 and 1997. The combination of ICA, GADA and IA2-ab were found in four subjects whereas six had two and 35 children one of these antibodies. After 10 years, six of the 1031 children had developed clinical diabetes and five of these six children were positive for islet antibodies. Two were positive for all three antibodies, two were positive for ICA and GADA, and one was positive for GADA. Among the individual autoantibodies, ICA showed the highest positive predictive value (29%) whereas the predictive value for the combination of two autoantibodies was highest for GADA and ICA (40%). Thus, GADA and ICA measurements may be a rational approach to detect schoolchildren at risk for developing diabetes.

Glutamate decarboxylase antibody levels predict rate of beta-cell decline in adult-onset diabetes.

Glutamate decarboxylase autoantibodies (GAD65Ab) and beta-cell function were evaluated at and 3 years after diabetes onset in consecutive subjects over 15 years of age. At onset, 21/32 (66%) insulin-treated patients (mean age 43, range 16-79 years) had GAD65Ab; all GAD65Ab persisted 3 years later. At onset, 20/82 (24%) non-insulin-treated patients (mean age 56, range 20-79 years) had GAD65Ab. Of those with persistent GAD65Ab, 8 non-insulin-treated and 11 insulin-treated patients consented to follow-up glucose and glucagon stimulation tests. For non-insulin-treated patients, quantitative GAD65Ab index at onset correlated inversely with 1 + 3 min C-peptide response to glucose (r = -0.68, P < 0.05) and to glucagon (r = -0.79, P < 0.05) 3 years later. Those with high (> 0.50) initial GAD65Ab index had lower C-peptide (fasting, 1 + 3 min after glucose and after glucagon) 3 years later, versus those with low (< 0.50) initial GAD65Ab index (P < 0.05). In conclusion, not only did GAD65Ab presence predict future insulin dependence, but higher GAD65Ab levels may mark more rapid decline in beta-cell function in apparent non-insulin-dependent diabetes.

Islet cell antibodies are associated with beta-cell failure also in obese adult onset diabetic patients.

To clarify the utility of islet cell antibodies (ICA) to correctly classify and predict insulin treatment in newly diagnosed diabetic subjects, ICA, body mass index (BMI), glycated hemoglobin (HbA1c), and fasting plasma C-peptide values were evaluated at and 3 years after diagnosis in 233 new, consecutively diagnosed, adult diabetic patients classified as obese or nonobese (National Diabetes Data Group, NDDG criteria). Among the 233 patients, 31 were nonobese ICA-positive (mean age at diagnosis 43 +/- 3 years), 55 nonobese ICA-negative (mean age at diagnosis 58 +/- 2 years), 7 obese ICA-positive (mean age at diagnosis 57 +/- 5 years), and 139 obese ICA-negative (mean age at diagnosis 58 +/- 1 years). Fasting C-peptide decreased (P < 0.05) in nonobese ICA-positive patients who after 3 years showed lower BMI (22.6 +/- 0.6 versus 24.5 +/- 0.4; P < 0.05), lower fasting C-peptide (0.14 +/- 0.06 nmol/l versus 0.71 +/- 0.07 nmol/l; P < 0.001), and higher frequency of insulin treatment [28/31 (90%) versus 6/45 (13%); P < 0.001] than nonobese ICA-negative patients.(ABSTRACT TRUNCATED AT 250 WORDS)

The efficacy of biochemical assays in assessing an IUGR risk-group, preselected with ultrasound fetometry.

Dehydroepiandrosterone sulphate, progesterone, estradiol, estriol and human placental lactogen (hPL) were biochemically assayed in a group of 92 pregnancies in which intra-uterine growth retardation was suspected. The group was selected with ultrasound fetometry at 32 weeks of gestation, and maternal blood was sampled at 33, 35, 37 and 39 weeks of gestation. The IUGR group consisted of 30 pregnancies resulting in the birth of an infant with a birthweight of 2 standard deviations or more below the mean for gestational age in the Malmö population. Intra-uterine growth trends were defined by serial ultrasound fetometry performed every second week. Both serum hormone and hPL content were examined in relation to birth-weight, occurrence of imminent asphyxia at delivery, Apgar score, and pH in the umbilical vein. Neither dehydroepiandrosterone sulphate, nor progesterone nor estradiol values correlated to any of the outcome variables. To some extent estriol values distinguished IUGR from non-IUGR fetuses but not until the 39th gestational week, whereas hPL was effective in this respect in all weeks studied. An hPL value below 4 mg/l predicted IUGR with a sensitivity ranging from 52% to 74%, and a specificity ranging from 85% to 78%. HPL correlated well with the subsequent intra-uterine growth rate, but not with the outcome variables studied.

[Better treatment of heart failure by measurements of natriuretic peptides. There are still remaining problems when it comes to the interpretation of measurement levels]. / Bättre behandling av hjärtsvikt med mätning av natriuretiska peptider. Tolkningen av mätvärdena bereder dock fortfarande problem.

The heart is increasingly being recognised as a major endocrine organ involved in haemodynamic homeostasis. Natriuretic peptides, i.e. atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP), affect renal, adrenal and central nervous system functions as well as vessel tonus and permeability thus causing decreased preload and afterload. Natriuretic peptides, BNP in particular, are independent risk factors for morbidity and mortality. They also have high negative predictive values for cardiac insufficiency indicating high diagnostic sensitivity for heart failure in outpatient practice. Monitoring of therapy for heart failure may be improved if BNP measurement is used in conjunction with clinical assessment. However, several problems remain to be solved, such as optimal decision limits in relation to sex and age for the assessment of heart failure.

[Laboratory diagnosis of gastrinoma. Nordic collaboration can improve the quality]. / Laboratoriediagnostik av gastrinom. Nordiskt samarbete kan ge ökad säkerhet.

Measurement of gastrin in serum or plasma in patients with gastrinoma may be complicated by the presence of circulating biosynthetic intermediates which may not be detected by commonly available immunoassays. In contrast, the "processing-independent analysis" of gastrins developed by professor Jens Rehfeld et al in Copenhagen detects gastrin forms irrespective of their size. The authors review gastrinoma pathophysiology, the biochemistry of gastrin and other biomarkers of gastrinoma, the differential diagnosis of hypergastrinemia as well as other methods currently employed in the workup of gastrinoma patients, and illustrate with a clinical case.

[How reliable is the laboratory? Increased needs of patient-related quality assurance]. / Kan man lita på laboratoriet? Okat behov av patientrelaterad kvalitetssäkring. Expertgruppen för endokrinologi inom EQUALIS.

Recent developments in medical care and research involve the increased use of immunochemical assays for hormones, tumour markers, vitamins and drugs. External quality assurance programmes using pooled human sera usually fail to detect analytical interference due to substances (e.g. anti-immunoglobulin or anti-ligand antibodies) present in individual serum specimens. The article reports on experience gained during a three-year period when specimens from individual patients attending a thyroid unit were distributed to hospital laboratories in Sweden for analysis. Specimen selection criteria were based on contradictory findings at the initial clinical or laboratory evaluation. The programme has given rise to the formation of a network of the laboratories involved, under the co-ordination of EQUALIS (External quality assurance in laboratory medicine in Sweden).