Specific insulin and proinsulin in normal glucose tolerant first-degree relatives of NIDDM patients

In order to identify early abnormalities in non-insulin-dependent diabetes mellitus (NIDDM) we determined insulin (using an assay that does not cross-react with proinsulin) and proinsulin concentrations. The proinsulin/insulin ratio was used as an indicator of abnormal ß-cell function. The ratio of the first 30-min increase in insulin to glucose concentrations following the oral glucose tolerance test (OGTT; I30-0/G30-0) was taken as an indicator of insulin secretion. Insulin resistance (R) was evaluated by the homeostasis model assessment (HOMA) method. True insulin and proinsulin were measured during a 75-g OGTT in 35 individuals: 20 with normal glucose tolerance (NGT) and without diabetes among their first-degree relatives (FDR) served as controls, and 15 with NGT who were FDR of patients with NIDDM. The FDR group presented higher insulin (414 pmol/l vs 195 pmol/l; P = 0.04) and proinsulin levels (19.6 pmol/l vs 12.3 pmol/l; P = 0.03) post-glucose load than the control group. When these groups were stratified according to BMI, the obese FDR (N = 8) showed higher fasting and post-glucose insulin levels than the obese NGT (N = 9) (fasting: 64.8 pmol/l vs 7.8 pmol/l; P = 0.04, and 60 min post-glucose: 480.6 pmol/l vs 192 pmol/l; P = 0.01). Also, values for HOMA (R) were higher in the obese FDR compared to obese NGT (2.53 vs 0.30; P = 0.075). These results show that FDR of NIDDM patients have true hyperinsulinemia (which is not a consequence of cross-reactivity with proinsulin) and hyperproinsulinemia and no dysfunction of a qualitative nature in ß-cells

PCR in the first oropharynx aspirate of the newborn: a possible source for identification of congenital infection agents

Relatamos um caso de diagnostico pre-natal de rubeola congenita. Apos o nascimento, alem da confirmacao feita atraves do exame fisico e sorologico do recem-nascido, o virus tambem pode ser demonstrado no primeiro fluido aspirado da orofaringe do recem-nascido, utilizando-se a reacao em cadeia da polimerase (PCR). Sugerimos que este fluido (colhido rotineiramente no momento da reanimacao neonatal) possa ser utilizado na pesquisa de outros agentes infecciosos, que nao sao facilmente identificados por outros metodos

Vitamin D receptor alleles and bone mineral density in a normal premenopausal Brazilian female population

Studies on the association between vitamin D receptor (VDR) polymorphism and bone mineral density (BMD) in different populations have produced conflicting results probably due to ethnic differences in the populations studied. The Brazilian population is characterized by a very broad genetic background and a high degree of miscegenation. Of an initial group of 164, we studied 127 women from the city of Spo Paulo, aged 20 to 47 years (median, 31 years), with normal menses, a normal diet and no history of diseases or use of any medication that could alter BMD. VDR genotype was assessed by PCR amplification followed by BsmI digestion of DNA isolated from peripheral leukocytes. BMD was measured using dual energy X-ray absorpitometry (Lunar DPX) at the lumbar site (L2-L4) and femoral neck. Most of the women (77.6 per cent) were considered to be of predominantly European ancestry (20.6 per cent of them reported also native American ancestry), 12.8 per cent were of African-Brazilian ancestry and 9.6 per cent of Asian ancestry, 41.0 per cent (52) were classified as bb, 48.8 per cent (62) as Bb and 10.2 per cent (13) as BB. The BB, Bb and bb groups did not differ in age, height, weight, body mass index or age at menarche, Lumbar spine BMD was significantly higher in the bb group (1.22 + 0.16 g/cm2) than in the BB group (1.08 + 0.14; P<0.05), and the Bb group presented an intermediate value (1.17 + 0.15). Femoral neck BMD was higher in the bb group (0.99 + 0.11 g/cm2) compared to Bb (0.93 + 0.12) and BB (0.90 + 0.09) (P<0.05). These data indicate that there is a significant correlation between the VDR BsmI genotype and BMD in healthy Brazilian premenopausal females.

A specific and highly sensitive time-resolved fluoroimmunoassay for human proinsulin

We describe a time-resolved fluoroimmunoassay specific for human proinsulin using a combination of two high-affinity monoclonal antibodies, one against insulin and the other specific for intact proinsulin and for split 65-66 and des 64-65 proinsulin forms. The assay employs only 200 micro liters of serum, with a detection limit of 0.1 pmol/l. The intra-assay variation coefficient was less than 3 percent between 3 and 1000 pmol/l. There was 0 percent cross-reaction with insulin, C-peptide, split 32-33 and des 31-32 proinsulin. Serum concentration of proinsulin was analyzed in 50 subjects during an oral glucose tolerance test (10 non-obese controls, 10 obese controls, 10 subjects with impaired glucose tolerance, 10 patients with type II diabetes meIlitus (DM) and fasting blood glucose (FBG) <140 mg/dl, and 10 patients with type II DM and FBG >150 mg/dl). Mean fasting serum proinsulin levels measured by this assay in non-obese controls (0.84 +/-0.90 pmol/l; 0.1-2.4 pmol/l) were lower than the results reported by her investigators. There was an increase of proinsulin related to obesity and increased glucose levels, suggesting that proinsulin levels increase with insulin resistance.

Comparison of the determination of insulin by a monoclonal antibody-based immunofluorometric assay and by radioimmunoassay

This paper describes an immunofluorometric assay (IFMA) for insulin and compares it with the classical radioimmunoassay (RIA). Monoclonal antibodies against insulin were produced and used to develop the IFMA. One, immobilized on microtiter plates, was used for capture, the other, labelled with Europium, was used as tracer antibody. The IFMA presentes sensitivity to an amount of insulin of 3 pmol/1 and acceptable valueus for intra- and interassay error. The IFMA presented superimposable curves for human insulin, Arg65/Gly66-split proinsulin and des-Lys64, Arg65, and no cross-reactivity with human proinsulin, Arg32/Glu33 -split and des-Arg31, Arg32. The RIA showed 100 percent cross-reactivity with human proinsulin, 90 pecent with des-Arg31, Arg32 and 170 percent with des-Lys64, Arg65. The assay were used to measure insulin in 300 serum samples from 50 subjects submitted to an oral glucose tolerance test (OGTT). Twenty were normal, 10 had impaired glucose tolerance and 20 non-insulin-dependent diabetes mellitus. The mean value (ñ SEM) obtained bu IFMA was 166.7 ñ 12.1 pmol/1 and the mean value obtained by RIA was 339.6 ñ 18.6, with a correlacion of r = 0.80 (P0.01). Comparison of basal insulin levels of the different groups of individuals using IFMA or RIA led to the same conclusions. The area under curve showed statistically significant differences only for the comparison between normal lean subjects and individuals with impaired glucose tolerance, when measured by RIA...(au)

Nocturnal urinary growth hormone excretion as a criterion for growth hormone deficiency

Nocturnal urinary growth hormone (U-hGH) levels measured by a sensitive immunoenzymometric assay were compared with hGH levels in serum before and after a clonidine test in healthy children and in children with short stature to determine whether U-hGH measurement is useful for the screening of hGH deficiency. The study was carried out on 19 healthy children (10 prepubertal and 9 pubertal subjects) and on 20 children with short stature, 10 with growth hormone deficiency (hGHD) and 10 with constitutional growth retardation. The diagnosis of hGHD was based on a blunted response to two provocative hGH tests in the appropriate clinical setting. Overnight urinary hGH secretion (mean of 3 collections) was measured by an immunoenzymometric assay. The best discrimination was obtained when the results were expressed as ng/h. Only one individual in the prepubertal group (U-hGH, 0.05 ng/h) and one patient in the growth retardation group (U-hGH, 0.08 ng/h) had a urinary hGH value below the highest value (0.17 ng/h) observed in the growth hormone deficiency group. The coefficient of correlation between urinary hGH in ng/h and post-clonidine peak was 0.50 (P = 0.0015), between urinary hGH in ng/l and post-clonidine peak was 0.48 (P = 0.0025), between urinary hGH in ng/l per hour and post-clonidine peak was 0.47 (P = 0.0027). The highest specificity (0.93), sensitivity (0.90), false negative rate (0.96) and false positive rate (0.82) were obtained when U-hGH was expressed as ng/h per night. Measurement of urinary nocturnal hGH excretion is a useful, simple, noninvasive method for the diagnosis of hGH deficiency. However, the day-to-day variability and wide normal range limit its usefulness in mild forms of hGH insufficiency

Cetoacidose diabética desencadeada por resistência imunológica à insulina / Diabetic ketoacidosis induced by immunologic insulin resistance

A cetoacidose diabética (CAD) é a emergência endocrinológica mais freqüente e de boa evoluçäo, na maior parte dos casos. Os autores apresentam evoluçäo atípica de três casos de CAD precipitada por resistência imunológica à insulina (RII). RELATO DE CASO. Três pacientes: H.M.L. (46 anos, diabetes mellitus (DM) tipo II, há 6 anos), D.R.J (39 anos, DM, secundário à pancreatopatia, há 11 anos) e D.L.S. (54 sanos, DM tipo II, há 9 anos) foram admitidos na Unidade de primeiro Atendimento do Hospital Säo Paulo em CAD: H.M.L. (glicemia: 716mg/dL, pH: 6,8), D.R.J. (glicemia: 684mg/dL, pH 6,.9) e D.L.S. (glicemia: 384mg/dL, pH: 7,2), todos apresentavam cetonúria. As necessidades de insulina para o controle metabólico foram: H.M.L.: 1.369UI, D.R.J.: 1.496UI, D.I.S. 1.369UI em, respectivamente: 212, 206 e 72 horas. Os anticorpos antiinsulina (AI) foram dosados por RE e ELISA: H.M.L.: 7.186nU/ml, 3,6IE; D.R.J.: 7,879nU/mL, 3,24IE; D.I.S: 8.377nU/mL, 2,88IE. O seguimento ambulatorial revelou queda progressiva dos níveis de AI:H.M.L.: 3.393nU/mL, 1,39, após dez meses da CAD; d.r.j.: 4,673Nu/Ml, 2,34 E d.i.s.: 1,510nU/mL, ambos após 18 meses da CAD. A queda nos níveis de anticorpos foi significativa nos três pacientes e foi acompanhada de melhor controle metabólico. Discussäo. A ausência de fator desencadeante, o elevado tempo, as altas doses de insulina empregadas para a compensaçäo metabólica levaram os autores à suspeita diagnóstica de RII. O diagnóstico foi confirmado pelos altos níveis séricos dos AI. O controle metabólico nestes pacientes foi obtido somente após a introduçäo de insulina na humanizada. CONCLUSAO. A resistência imunológica à insulina pode ser uma das causas de CAD sem fator precipitante aparente e má resposta às medidas terapêuticas habituais

Detection of insulin antibodies by radioassay and ELISA: interrelation and correlation with metabolic control in type I diabetes

1. The literature suggests that the radioassay (RA) and ELISA detect different types of insulin antibodies (IA) (Wilkin et al., 1989. Diabetes, 38: 172-181). 2. In the present study we evaluated the relationship between these two antibodies and their involvement in the metabolic control of Type I diabetic (DMI) patients. 3. IA were measured by RA and ELISA in sera obtained from 34 patients (age: 9-16 years, median = 12.5 years; clinical duration of DMI: 0.1-11.0 years, median = 1.7 years) treated with different types of insulin [purified (bovine + porcine) N = 18, and monocomponent (porcine or human) N = 16] and submitted to various degrees of metabolic control as assessed by glycosylated serum protein (GSP) levels: range, 3.4-13.5; median = 8.7; normal value, 0.8-2.4. 4. Insulin antibody levels measured by RA were: 3264 +/- 300 nU/ml (mean +/- SEM, normal value < 60 nU/ml) and by ELISA: 0.74 +/- 0.11 ELISA index (EI) (normal value, < 0.53). No correlation was found between IA levels measured by RA and ELISA, or between duration of the disease or insulin daily necessity and IA by either method. GSP was positively correlated with IA determined by ELISA (rS = 0.43, P < 0.01) but not with IA determined by RA. 5. The patients on purified bovine + porcine insulin had higher titers of IA by ELISA, compared to those of patients on monocomponent (0.96 +/- 0.15 vs 0.50 +/- 0.13 EI, P < 0.03, while IA levels measured by RA did not differ between groups. 6. These data show that RA or ELISA assays provide different serum titers of IA in insulin-treated diabetics and data obtained with ELISA correlated best with the metabolic control of Type I diabetic patients.

Associaçäo entre auto-anticorpos anti-pro-insulina e anti-insulina com diabetes mellitus do tipo I / The association between insulin and proinsulin autoantibodies with tipe I Diabetes Mellitus

O presente trabalho compara a incidência de auto-anticorpos anti-insulina (IAA) e anti-pró-insulina (PAA) em diabéticos do tipo I de início recente e em seus parentes de primeiro grau. Foram estudados 33 indivíduos normais (grupo I), 16 diabéticos do tipo I de início recente (grupo II) e 141 parentes em primeiro grau de diabéticos do tipo I (grupo III). Os IAA e PAA foram determinados pelo método de radioensaio, sendo considerados anormais níveis de IAA acima de 0,584 pmol/L e de PAA acima de 0,441 pmol/L. Näo foram observadas diferenças significantes quanto a idade e sexo entre os 3 grupos. Nos indivíduos normais os níveis de PAA foram significantemente menores do que os de IAA. Entre os diabéticos de início recente foi encontrada uma incidência de IAA de 37,5 por cento e de PAA de 25,0 por cento, näo ocorrendo, entretanto, diferenças significantes entre os níveis destes dois anticorpos. Entre os parentes em primeiro grau a incidência de IAA foi de 3,5 por cento e de PAA de 7,8 por cento, näo ocorrendo também diferenças entre os dois testes. Houve uma correlaçäo significante entre os níveis dos IAA e dos PAA no grupo de diabéticos de início recente (r=0,64; p < 0,05). Os IAA e PAA parecem estar dirigidos contra o mesmo determinante antigênico e, portanto, têm o mesmo valor preditivo para o DM tipo I

Aspectos da fase näo-insulinodependente do diabetes mellitus do tipo I / Aspects of non-insulin-dependent phase of type I diabetes mellitus

Trata-se de um caso de diabetes mellitus do tipo I(DMI) no qual tivemos a oportunidade de diagnosticá-lo 23 meses antes das suas manifestaçöes clínicas mais freqüentes. Durante esse período foram observadas alteraçöes como o retorno de enurese, diminuiçäo na velocidade de crescimento e episódios de hiperglicemia e/ou glicosúria transitórios, apresentadas pela paciente, que podem näo ser devidamente valorizadas, na rotina clínica. Como, também, o aparecimento de marcadores imunológicos (ICA) e alteraçöes precoces na secreçäo de insulina (diminuiçäo na sua primeira fase de liberaçäo) vários meses antes do DMI manifesto. Esses marcadores imunológicos e essas alteraçöes endócrinas deveriam, se possível, ser pesquisados em pacientes com o quadro clínico inicial aqui apresentado, e em parentes jovens de DMI, no sentido de se detectar indivíduos com elevado risco de evoluírem para a fase manifesta dessa moléstia. O seguimento desses pacientes possibilitaria o diagnóstico precoce do DMI e a aplicaçäo de medidas no sentido de impedir a deteriorizaçäo total das células beta-pancreáticas e a evoluçäo para distúrbios metabólicos mais graves, como a cetoacidose diabética, com morbidade e mortalidade reconhecida

Insulin autoantibodies in first degree relatives of type I diabetic patients

Insulin autoantibodies (IAA) of first-degree relatives of type diabetic patient and recent-onset type I diabetics were measured by radioimmunoassay. A cut-off of 60 nU/ml was established on the basis of the values of normal control individuals. The intra-assay coefficient of variation was 9.2% for a moderately positive serum (1908 ñ 176 nU/ml (mean ñ SD), N=7; range, 1708 to 2158 nU/ml). The interassay coefficient of variation was 23.8% for a negative (normal control) serum (28.1 ñ 6.7 nU/ml, N=6; range, 22 to 39 nU/ml) and 14.5% in a highly positive serum (6185 ñ 899 nU/ml, N=7; range, 5053 to 7009 nU/ml). Insulin autoantibody levels (mean ñ SEM) were 19.3 ñ 2.8 nU/ml (range, =-19 to 40 nU/ml) in 25 controls, 24.8 ñ 3.4 nU/ml (range, -17 to 59 nU/ml) in 41 type II diabetic patients, 18.5 ñ 2.4 nU/ml (range, -58 to 268 nU/ml) in 171 first-degree relatives of type I diabetic patients and 208.9 ñ 87.0 nU/ml (range, 10 to 1101 nU/ml) in 16 recent-onset type I diabetic patients. IAA levels were significantly higher in the last group compared with the other groups (P<0.01). None of the controls or type II diabetics exceeded the upper limit of normalyity. In contrast, 9 of 171 (5.3%) first-degree relatives and 9 of 16 (56.0%) recent-onset type I diabetic patients had IAA levels above the 60 nU/ml cut-off point. These data indicate that this method is effective for the detection of individuals who are at high risk to develop type I diabetes

Do impaired glucose tolerance and diabetes mellitus interfere with the interpretation of the growth hormone response to the oral glucose tolerance test ?

The ability of glucose to suppress growth hormone (GH) secretion is well known and the glucose test is widely used for the diagnosis of acromegaly. However when suspected acromegaly is associaterd with diabetes mellitus (DM) or impaired glucose tolerance (IGT) the interpretation of the GH response to the oral glucose tolerance test (OGTT) may be difficult. Recently, Haltori et al. (Journal of clinical endocrinology and metabolism, 70: 771-778, 1990), using a highly sensitive (1.5 ng/l) polyclonal antibody-based immunoenzymometric assay, found no differences in the GH response to glucose load among control, IGT and DM patients. We employed a less sensitive (100 ng/l) but monoclonal antibody-based immunoenzymometric assay to measure the serum GII levels of 19 normal subjects, 11 patients with DM and 11 patients with IGT to determine the effect of glucose intolerance on the GH response to the OGTT. Complete suppression of GH (<0.1 ug/l) was achieved in 73% o9f the controls with a mean nadir of 0.17 ñ 0.16 ug/l (range, <0.1-0.6 ug/l). GH was completely suppressed in 82% of the the diabetes with a mean nadir of 0.58 ñ 1.21 ug/l (range, <0.1-4.0 ug/l). However, complete suppression occurred in only 27% of the IGT patients with a nadir of 1.09 ñ 2.08 ug/l (range, 0.1-7.0 yg/l), which was statisticaly higher than observed for controls and diabetics. We conclude that plasma GH plasma GH levels after glucose loading of IGT patients should be interpreted with caution because an abnormal response can be detected when some sensitive immunometric assays are employed

Relationship between insulin antibodies and metabolic control in type I diabetes mellitus

1. The objective of the presente study was to investigate whether a change in insulin therapy from bovine to purified porcine insulin would result in a decreased level of insulin antibodies (IA) in type I diabetic patients and whether there would be better metabolic control. 2. Insulin antibodies were measured by ELISA. Fifteen type I diabetic patients were prospectively followed for 8 months with monthly evaluations after changing insulin therapy from bovine to purified porcine insulin. 3. Group I patient (N = 4) had > ou = 1.5 (value obtained by dividing the ELISA absorbande of the tested serum by the absorbance of a standard serum) at the beginning of the study. For group I patients, the modification of insulin therapy caused a 57% reduction in insulin antibody levels, and this reduction was correlated with a decrease in 24-hour glycosuria (rs = 0.66, P < 0.001) and glicated protein (rs = 0.65, P < 0.01). Group II patients (N = 8) had IA < 1.5 and > ou = 0.3 and group III (N = 3 had IA < 0.3. Insulin antiblody levels were unchanged during the follow-up period in both group II and group III. 4. We also studied endogenous insulin secretion, measured as fasting C-peptide, and its relationships with metabolic control and insulin antibody levels. Patient with residual insulin secretion (C-peptide > 60 pmol/l) showed lower levels of 24-h glycosuria, glycated protein and glycated hemoglobin. Furthermore, in this group of patients a negative correlation was found between C-peptide and insulin antibody levels (rs=0.36, P < 0.01). 5. We conclude that insulin antibodies could be one of the factors having a detrimental effect on metabolic control