Clinical outcome and economic impact of aminoglycoside peak concentrations in febrile immunocompromised patients with hematologic malignancies

The aim of this study was to investigate the clinical and economic significance of aminoglycoside peak concentrations in febrile neutropenic patients with hematologic malignancies. Sixty-one patients were treated according to protocol II of the Paul-Ehrlich-Gesellschaft: initial application of gentamicin or tobramycin in combination with a cephalosporin or ureidopenicillin and, after 3 days, a potential change of antibiosis to be decided in case of nonresponse. At the same time, samples were collected by an independent controller. We found a significant dependence of clinical outcome on aminoglycoside peak concentrations (P = 0.004). Twelve of 17 patients with peak concentrations > 4.8 mg/L, but only 13 of 44 patients with concentrations < or = 4.8 mg/L, responded to initial therapy. Average infection-related costs per patient with peak values > 4.8 mg/L were US$1429, $1790, and $1701 for nursing, diagnostics, and therapeutics, respectively (total $4920). Expenses for patients with peak concentrations < or = 4.8 mg/L were approximately 1.8-fold higher (average total $8718). If all 61 patients had achieved peaks > 4.8 mg/L, the potential savings would have totalled $167,112. We conclude that neutropenic patients form a target group for successful pharmacokinetic intervention and cost saving.

Longitudinal study of fasting proinsulin in 148 siblings of patients with insulin-dependent diabetes mellitus. Study Group on Childhood Diabetes in Finland

OBJECTIVE

To follow proinsulin immunoreactive material (PIM) in healthy siblings from the time of diagnosis of insulin-dependent diabetes mellitus (IDDM) in the proband, for at least 2 years.

DESIGN AND METHODS

The study comprised 148 siblings representing 112 families. The siblings were recruited from the nationwide 'Childhood Diabetes in Finland' study and tested for immunological markers. If a sibling was found positive for islet cell antibodies (ICA) or insulin autoantibodies (IAA), PIM sampling was extended beyond 2 years.

RESULTS

Of the 148 siblings, 12 developed IDDM 3-53 months after the diagnosis in the proband. Eleven of these siblings exhibited initially normal PIM concentrations. In nine siblings, samples were available both more than 6 months and during the last 6 months before the diagnosis of IDDM; PIM concentrations increased in seven, remained unchanged in one, and decreased in one in the period up to the diagnosis of IDDM (P < 0.05). Median PIM concentration did not change significantly during the examination period of 2 years in the 136 siblings who did not contract IDDM. Constantly increased PIM concentrations were found in 12 of the 136 siblings who did not develop IDDM. These 12 siblings were all ICA negative.

CONCLUSION

In healthy siblings of IDDM patients exhibiting an initially low PIM concentration, an abrupt increase in PIM seems to precede the clinical manifestation of IDDM within 0-6 months. However, there were too few patients available to close follow-up to allow calculation of any predictive value of this increase. Persistently increased PIM concentrations were present in some healthy siblings who did not develop IDDM. The reason for that finding remains unclear, but it could be associated with previous B cell damage.

Deregulated simultaneous expression of multiple glucose transporter isoforms in malignant cells and tissues

To evaluate the molecular and functional characteristics of upregulated glucose uptake in malignant cells, the expression of four glucose transporter (Glut) isoforms as well as glucose transport were determined in benign and malignant cell lines and tissues. In vivo distribution of Glut proteins was examined by immunocytochemistry in 30 breast cancer samples. In comparison with benign controls upregulation of Glut 1 mRNA and Glut 3 mRNA was shown. Glut 2 mRNA could not be detected. Glut 4 mRNA was found in various malignant cell lines in contrast to the physiological restriction of Glut 4 to terminally differentiated muscle and fat cells. While Glut 3 protein was not detectable in non-neuronal tissues, the degree of overexpression of Glut 1 and 4 corresponded to the expression level of the respective mRNAs. 57% of the breast cancer tissues showed positivity for Glut 1, 43% for Glut 4. Functional integrity of Glut 4 was demonstrated by preserved insulin-responsiveness. In cell lines, glucose transport activity was positively correlated with proliferation rate. Enhanced translocation of Glut 4 to the plasma membrane in correlation with high Ki-67 positivity in tissues pointed to the same association in vivo. C-myc overexpression had no detectable influence on Glut expression. In conclusion, malignant cells demonstrate quantitative as well qualitative changes of Glut expression and activity. Alteration of differentiation-adapted transcription and expression of cell-specific Gluts may represent a part of the transformation process and contribute to tumor progression.

Influence of cycloheximide-mediated downregulation of glucose transport on TNF alpha-induced apoptosis

Enhancement of cellular sensitivity to TNF alpha-induced apoptosis by cycloheximide (CX) has been attributed to its quality as an inhibitor of protein synthesis, presumably by prevention of the synthesis of short-lived death antagonists. CX is also known to interfere with glucose transport, which in turn influences cell death. Hexose uptake, expression of glucose transporter (Glut) mRNAs and proteins, and other related factors were therefore examined upon induction of apoptosis with TNF alpha and CX in breast cancer cell lines. In the early phase of apoptosis, a dramatic decrease in glucose transport was observed, preceded by stimulation of Glut 1 and 3 mRNAs. Transport downregulation was also detectable upon incubation with CX alone, albeit to a lesser extent. With the doses used, TNF alpha had no such effect. Protein synthesis was inhibited to the same degree in TNF alpha/CX-treated apoptotic cells compared to viable CX-treated cells. Diminished hexose uptake was associated with decreased Vmax, while Glut affinity remained unaffected. As there was no evidence for changes in total cellular Glut content or for Glut translocation from the plasma membrane, a diminished intrinsic activity of Gluts must be postulated. In conclusion, CX is proposed to contribute to TNF alpha-induced apoptosis predominantly by interference with glucose transport; the exact nature of this effect remains to be elucidated.

Bankart repair for anterior instability of the shoulder. Long-term outcome

Anterior instability of the shoulder is a commonly encountered entity in orthopaedic practice. The Bankart procedure is considered by many surgeons to be the treatment of choice for this condition. Despite its widespread popularity, there have been no studies on the long-term outcome of the Bankart procedure as far as we know. Sixty shoulders (fifty-six patients) that had been followed for a minimum of eight years after a Bankart procedure were evaluated for range of motion, stability, and strength according to the data form of the American Shoulder and Elbow Surgeons for examination of the shoulder. The results for the involved shoulder were compared with the findings for the contralateral, normal shoulder. All patients completed a questionnaire regarding the history of the instability of the shoulder, the level of participation in sports before and after the operation, the preoperative and postoperative level of pain, and whether the patient had ever sustained a dislocation that needed reduction by a physician. Information about the current ability of the patient to function at home, at work, and during sports also was requested. In addition, the patients were asked to rate the results of the operation and to indicate whether they would have the same procedure again for the same problem. At a mean of 11.9 years after the operation, the mean loss of external rotation was 12 degrees (range, 0 to 30 degrees) (p < 0.0001). There were no significant differences in forward elevation, abduction, or internal rotation between the involved shoulder and the contralateral, normal shoulder. One patient had crepitus on glenohumeral motion. Fifty-five of the fifty-six patients returned to the occupation that they had had preoperatively, without having to alter their activities. Twenty-eight patients had mild pain with strenuous activity, and one patient had pain at rest. Three patients had a dislocation of the involved shoulder because of a new traumatic event more than three years postoperatively. Fifty-two patients rated the result as good or excellent; three, as fair; and one, as poor. Fifty-four patients said that they would have a Bankart procedure performed again for the same problem. We present a new system for rating the shoulder that emphasizes function and is based specifically on the goals stated by the patients to be most important with regard to the shoulder. Using this system, we found that the Bankart procedure offers an excellent objective long-term outcome with a high degree of patient satisfaction.

Differential expression of apoptosis associated genes bax and bcl-2 in ovarian cancer

The prognostic value of various molecular markers, which adequately account for the tumor biology and disease behaviour of ovarian cancer, is still unclear. Recent studies have focused on the role of genes regulating the balance between proliferation and cellular suicide, apoptosis. In the present study, tumor tissue from 215 patients with ovarian cancer was immunohistochemically analysed for Bax- and Bcl-2-expression. There was an association between Bcl-2-expression (30%) and factors of favourable prognosis. In contrast, Bax-expression (47%) was related to bad clinical outcome, especially in cases without concomitant Bcl-2-expression. In patients with Bcl-2-positive/Bax-negative tumors, overall survival was significantly longer (p = 0.0379) than in patients with Bcl-2- and Bax-negative tumors. Respectively, expression of Bax without Bcl-2-expression was correlated with bad clinical outcome (p = 0.033). The difference in overall survival was most striking (p = 0.0007) between patients with Bax-positive/Bcl-2-negative and Bcl-2-positive/Bax-negative tumors. This could also be demonstrated for the various subgroups of different tumor grade and stage. It may be speculated, that alteration of the Bax/Bcl-2-balance may influence the clinical course by deregulation of programmed cell death and altered sensitivity to chemotherapy.

Proinsulin immunoreactivity in recent-onset IDDM: the significance of insulin antibodies and insulin autoantibodies

OBJECTIVE

To study the natural history of fasting proinsulin immunoreactivity (PIM) during the first 30 months of IDDM and its relationship to fasting C-peptide and insulin antibodies.

RESEARCH DESIGN AND METHODS

An incidence cohort of 204 consecutive newly diagnosed IDDM patients were followed prospectively, having blood drawn for measurements at diagnosis and at 1, 3, 6, 9, 12, 18, 24, and 30 months. A sensitive enzyme-linked immunosorbent assay was used for the determination of PIM.

RESULTS

All patients had detectable fasting PIM in plasma at diagnosis, with a median value and interquartile range of 3.5 pmol/l (2.2-6.2). The median PIM level increased during the first months of IDDM to reach a peak at 9-12 months (9.9-10.3 pmol/l). PIM then declined gradually to 5.6 pmol/l (1.9-13.5) at 30 months without reaching baseline. PIM at each time point was widely scattered in a skewed log-normal distribution without signs of bimodality. After the onset of insulin treatment, median insulin antibody level increased and declined in a similar pattern. Both PIM and antibody level were significantly higher in children and adolescents compared with adults. However, stepwise multiple regression analysis showed that age was only of minor importance for the PIM variation during the study period. Insulin antibody level and fasting C-peptide were the major determinants at 3-30 months, accounting for approximately 40% of the variation (R2). Blood glucose was of minor importance, and insulin dose, HbA1c, and BMI were of no importance. The correlation between fasting PIM and fasting C-peptide improved (R2 doubled) if the insulin antibody level was accounted for. Further, the slope of the correlation curve between PIM and C-peptide increased threefold when antibody binding was > 4%. At diagnosis, insulin autoantibodies could be detected in 19% of the patients. Their presence predicted higher proinsulin at 1-3 months, a higher insulin dose the 1st year, and higher levels of insulin antibodies later in the study.

CONCLUSIONS

Circulating insulin antibodies may affect the level of PIM in IDDM, probably by adding a pool of IgG-bound PIM thereby increasing half-life and plasma concentration. This may explain why C-peptide and PIM levels do not change in concert during the 1st years of IDDM. Unlike C-peptide, PIM can not therefore quantitate beta-cell secretion unless the presence of insulin antibodies is ruled out.

Proinsulin, C-peptide, and insulin in normal subjects during an 8-h hyperglycemic clamp

Increased concentrations of proinsulin immunoreactive material (PIM) absolutely or relative to insulin is a characteristic finding in patients with non-insulin-dependent diabetes mellitus (NIDDM). The aim of this study was to test if 8 h or mild hyperglycemia (7-9 mmol/l) in healthy subjects could induce a preferential secretion of PIM from B cells. Serum concentrations of insulin, C-peptide and PIM were measured every 10 min during the 8 h of continuous glucose infusion in nine normal-weight healthy subjects without diabetes among their first-degree relatives. After a gradual rise in B-cell peptides, a steady state was reached. From 4 to 8 h no further difference in insulin, C-peptide or PIM concentration was found. Fasting PIM/C-peptide and PIM/insulin ratios of 0.5% and 2.3% increased during the glucose clamp to levels of 1.4% and 7.6%, respectively. Neither testing the regression slope nor comparing individual time points showed any significant difference for the PIM/C-peptide ratio from 2 to 8 h and for the PIM/insulin ratio from 3 to 8 h. These results do not support the hypothesis that an increased glucose drive per se results in an altered B-cell function with increasing PIM/C-peptide ratio. At least 8 h of mild hyperglycemia in healthy subjects does not progressively alter B-cell function.

Expression of Bax in relation to Bcl-2 and other predictive parameters in breast cancer

BACKGROUND

It has been suggested that modification of the physiological susceptibility to induction of programmed cell death in transformed cells contributes to the pathogenesis of cancer. One of the major regulators of cell death is the bcl-2 family. In breast cancer, altered expression of Bcl-2 has been described. Distribution of its counterpart Bax and the differential expression pattern have still to be evaluated.

PATIENTS AND METHODS

Bax expression was investigated by immunohistochemistry in 122 primary breast cancers. Results were correlated with expression of Bcl-2 and other variables of predictive value.

RESULTS

There was a positive association between Bax expression and histological grading, (over)expression of c-erbB-1 and -2 and proliferative activity. The correlation was most significant in cases where no concomitant Bcl-2 expression could be detected. In the same subgroup an inverse correlation with positivity for estrogen (and progesterone) receptors was observed. The presence of Bax was not significantly associated with either tumor type and size, nodal status or expression of c-erbB-3.

CONCLUSION

Expression of Bax was coupled with negative histopathological features, especially when expression of Bcl-2 was downregulated concomitantly. It may appear that alterations of the differential Bax/Bcl-2 expression pattern take part in deregulation of proliferation and loss of differentiation, thus playing an important role in malignant progression.

Increased molar proinsulin-to-insulin ratio in women with previous gestational diabetes does not predict later impairment of glucose tolerance

OBJECTIVE

To evaluate if an increased proinsulin-to-insulin ratio (PI/I) in former gestational diabetes mellitus (GDM) subjects could be a marker for later impairment of glucose tolerance.

RESEARCH DESIGN AND METHODS

This study is a prospective follow-up. In a previous follow-up study of former GDM subjects 3-4 years after an index pregnancy, an increased PI/I was found also in normoglycemic nonobese former GDM subjects compared with control subjects. A 75-g oral glucose tolerance test (OGTT) was performed 3 years after the first follow-up, i.e., 6-7 years after the index pregnancy in 97 of the former GDM subjects and in 23 control subjects. A 75-g OGTT according to the World Health Organization was performed. Glucose, insulin, proinsulin, and C-peptide were determined at 0, 30, 60, 90, 120, 150, and 180 min after the glucose intake.

RESULTS

Since the first follow-up, an additional 3 in 97 (3.1%) and 15 in 97 (15.5%) of the former GDM subjects had NIDDM or impaired glucose tolerance (IGT), respectively. All control subjects still had a normal OGTT. The fasting PI/I at follow-ups 1 and 2 was significantly correlated in the former GDM subjects (r = 0.41, P < 0.001) and in the control group (r = 0.46, P < 0.05). There was no significant correlation between the PI/I in follow-up 1 and the fasting or 2-h glucose values at follow-up 2. If GDM subjects with a PI/I in the upper quartile in the first follow-up were compared with those with a lower PI/I, there were no significant differences in outcome of OGTT in the second follow-up.

CONCLUSIONS

The hypothesis that an increased fasting PI/I is a marker for later development of NIDDM or IGT in former GDM subjects could not be supported.

Bcl-2 protein expression in breast cancer in relation to established prognostic factors and other clinicopathological variables

BACKGROUND

Bel-2 inhibits most kinds of programmed cell death and provides a selective survival advantage to various cell types. Bcl-2 is physiologically expressed in ductal epithelia of the normal breast. The biological significance of Bcl-2 (over)expression for the development and progression of breast cancer has still to be evaluated.

PATIENTS AND METHODS

A series of 133 primary breast cancers was investigated for expression of the Bcl-2 protein by immunohistochemistry of paraffin-embedded tissue sections. Results were correlated with other variables of established or presumed predictive value.

RESULTS

A significant positive correlation was observed between Bcl-2 expression and positivity for estrogen and progesterone receptors (p < 0.001). High proliferative activity as assessed by Ki-67 staining correlated inversely with Bcl-2 expression (p < 0.001). Bcl-2 immunostaining was not related to positivity for c-erbB-1. It was negatively associated with overexpression of c-erbB-2 (p = 0.04), whereas a strong positive correlation was found with expression of c-erbB-3 (p = 0.01). There was a significant inverse correlation between histological grading and immunoreactivity for Bcl-2 (p < 0.001). N0 tumors tended to be Bcl-2 positive, but differences were not statistically significant.

CONCLUSION

Bcl-2 was detected predominantly in differentiated tumors. Expression was associated with other favorable histopathological features and predictors of positive clinical outcome. Loss of Bcl-2 expression seems to be linked to loss of hormonal regulatability, increased dedifferentiation and deregulated proliferation.

Proinsulin immunoreactivity in identical twins discordant for noninsulin-dependent diabetes mellitus

Disproportionate elevation [increased proinsulin/insulin (PI/INS) ratio] of PI immunoreactivity is associated with noninsulin-dependent diabetes mellitus (NIDDM). The nature of this abnormality is not known. To address the question of whether genetic factors contribute to hyperproinsulinemia, we measured fasting levels of PI immunoreactivity, intact INS, and C peptide (CP) in 12 pairs of monozygotic twins discordant for NIDDM for a mean (+/- SEM) period of 9 +/- 3 yr. Thirteen age- and body mass index-matched healthy subjects without any family history of NIDDM acted as controls. The nondiabetic twins had levels of fasting INS, CP, PI, PI/CP, and PI/INS similar to those of control subjects. Fasting levels of PI, and PI/CP and PI/INS ratios were significantly 2- to 3-fold elevated in NIDDM twins compared to those in both nondiabetic twins and control subjects. To investigate whether hyperproinsulinemia in these NIDDM patients was due to a differential elevation of intact PI or conversion intermediates, we analyzed PI profiles in NIDDM twins and normal subjects by high pressure liquid chromatography. PI was heterogeneous and consisted mainly of des(31,32)-PI and intact PI in both NIDDM patients and normal subjects, with no major difference in composition between the groups. Small amounts of des(64,65)-PI (0-11%) were measured in some patients and normal subjects. The results suggest that hyperproinsulinemia is not a genetically determined trait per se in NIDDM. Disproportionately elevated PI levels seem to be related to the actual disease process. Further conversion of intact PI and des(31,32)-PI may be equally impaired in NIDDM.

Disproportionately elevated proinsulin levels precede the onset of insulin-dependent diabetes mellitus in siblings with low first phase insulin responses. The Childhood Diabetes in Finland Study Group

The objective of this study was to test whether levels of proinsulin immunoreactivity (PIM) relative to those of insulin immunoreactivity (IRI) or C-peptide are changed and related to subclinical beta-cell dysfunction in siblings of insulin-dependent diabetes mellitus (IDDM) patients. Twenty-three siblings, previously found positive for islet cell antibodies and/or insulin autoantibodies, were divided into 2 groups according to their first phase insulin response (FPIR) to i.v. glucose tolerance tests (IVGTTs) sequentially performed during an observation period of 2 yr. Eleven siblings had diminished FPIR on at least 1 occasion (group 1), whereas 12 siblings had a normal FPIR on all occasions studied (group 2). All underwent a further IVGTT (0.5 g glucose/kg BW), and serum samples were taken at 0, 1, 3, 6, 10, 20, 30, 40, 50, and 60 min. The 2 groups had comparable median age, female/male ratio, weight, height, fasting blood glucose, immunoreactive insulin, C-peptide, and insulin autoantibodies levels, but group 1 had significantly higher islet cell antibodies levels. Fasting median PIM/IRI and PIM/C-peptide ratios were 2- to 3-fold higher in group 1 [10.5% (range, 1.8-93.8%) vs. 5.2% (range, 1.9-14.3%) and 3.3% (range, 0.4-23.1%) vs. 1.3% (range, 0.7-2.6%; P < 0.05]. Fasting PIM/C-peptide ratios correlated inversely with FPIRs (rs = -0.68; P < 0.01). During glucose stimulation, maximal responses of IRI and C-peptide were 4-fold lower in group 1, and the time of maximal responses of IRI and C-peptide occurred later in group 1 than in group 2. In contrast, no difference in maximal responses of PIM was found, but the time of maximal responses of PIM occurred later in group 1. Nine of 11 siblings in group 1 presented with IDDM 1-28 months after the test, compared to none in group 2. In group 1 a paradoxical inhibitory response of PIM was observed during the first 6 min of the IVGTT. These data indicate that fasting PIM/IRI and/or PIM/C-peptide ratio reflects subclinical beta-cell dysfunction in prediabetic subjects with evidence of immunological beta-cell assault and suggests that an elevated ratio may be an additional marker for later development of IDDM.

Creatinine height index and lean body mass in adult patients with insulin-dependent diabetes mellitus followed for 7 years from onset

The 24-hour urinary creatinine excretion value can be used as an index of protein nutrition; the creatinine height index and lean body mass can be estimated from this value. On the basis of longitudinally measured 24-hour urinary creatinine excretions during the initial 7 years of type 1 diabetes in an incidence cohort of 147 adult patients, we studied creatinine height index and lean body mass and possible relationships to sequential measurements of glycated hemoglobin (HbA1c). The patients were divided into four groups according to their glycemic control during these 7 years: I, HbA1c < 7.4% (n = 37); II, HbA1c 7.4% to 8.2% (n = 37); III, HbA1c 8.3% to 8.9% (n = 38); IV, HbA1c > 8.9% (n = 35). One year after the onset of diabetes, height indices were as follows (% of normal values, median and quartiles): I, 104% (90 to 116); II, 101% (78 to 105); III, 121% (92 to 128); IV, 87% (78 to 109) ([IV] < [I to III]; p < .05). During the following 6 years no significant differences in height index were observed among the four groups of patients at any point in time. Slightly higher calculated lean body mass values were found in the most well-controlled patients, but otherwise no differences were found in lean body mass. It is concluded that, apart from the first year, indices of protein nutrition remain normal during the initial 7 years of type 1 diabetes, even in patients with poor glycemic control.

[Necrotizing hepatitis with a fatal outcome after carbimazole therapy]

A 74-year-old woman developed weakness, lack of appetite and abdominal swelling 7 months after starting treatment with carbimazole (10 mg/d for 10 weeks) and, subsequently, radioiodine for hyperthyroidism. Physical examination revealed generalized oedema and ascites. Computed tomography showed a liver of normal size but infiltrated by nodules up to 4 cm in diameter. Erythrocyte sedimentation rate was raised and there were abnormal concentrations of haemoglobin, total proteins, liver enzymes and creatinine, as well as decreased platelet and white cell counts. Thyroid function was normal. Viral and autoimmune diseases were largely excluded. Liver biopsy showed a severe, highly active hepatitis with parenchymal necroses, large-drop fatty infiltration and intralobular granuloma-like inflammatory reactions, as well as lympho-histiocytic inflammation of the portal areas. The most likely cause was the carbimazole treatment. In addition to symptomatic treatment she received prednisone (1 mg/kg), because an allergic diathesis could not be excluded. But she died of hepatic failure 6 weeks after admission.

Highly sensitive enzyme immunoassay of proinsulin immunoreactivity with use of two monoclonal antibodies

A highly sensitive two-site sandwich ELISA measuring total proinsulin immunoreactive material in serum or plasma was developed. The assay was based on two monoclonal antibodies, an anti-C-peptide antibody bound to a microtest plate and a biotin-labeled anti-insulin antibody. The detection limit (3 SD above zero value) in buffer was 0.05 pmol/L, corresponding to 0.25 pmol/L in human serum (diluted 1:5). The linear calibrator range was 0.05-20 pmol/L. Interassay CVs were 4.7% at a median (range) of 2.3 pmol/L (1.4-2.8 pmol/L, n = 8), 6.7% at 5.1 pmol/L (3.3-8.0 pmol/L, n = 8), and 8.7% at 10.0 pmol/L (8-12 pmol/L, n = 10). Mean analytical recovery of added human proinsulin (hPI) (2, 5, and 10 pmol/L) to serum was 84% (range 68-128%, n = 9). Human insulin and human C-peptide did not cross-react at 5000 and 10,000 pmol/L, respectively. The four major proinsulin conversion intermediates reacted 65-99%: split(32-33)hPI 74%, des-(31,32)hPI 65%, split(65-66)hPI 78%, and des(64,65)hPI 99%. All serum values from 38 fasting healthy subjects were above the detection limit: median (range) 4.0 (2.1-12.6) pmol/L.

Highly sensitive enzyme immunoassay of proinsulin immunoreactivity with use of two monoclonal antibodies

A highly sensitive two-site sandwich ELISA measuring total proinsulin immunoreactive material in serum or plasma was developed. The assay was based on two monoclonal antibodies, an anti-C-peptide antibody bound to a microtest plate and a biotin-labeled anti-insulin antibody. The detection limit (3 SD above zero value) in buffer was 0.05 pmol/L, corresponding to 0.25 pmol/L in human serum (diluted 1:5). The linear calibrator range was 0.05-20 pmol/L. Interassay CVs were 4.7% at a median (range) of 2.3 pmol/L (1.4-2.8 pmol/L, n = 8), 6.7% at 5.1 pmol/L (3.3-8.0 pmol/L, n = 8), and 8.7% at 10.0 pmol/L (8-12 pmol/L, n = 10). Mean analytical recovery of added human proinsulin (hPI) (2, 5, and 10 pmol/L) to serum was 84% (range 68-128%, n = 9). Human insulin and human C-peptide did not cross-react at 5000 and 10,000 pmol/L, respectively. The four major proinsulin conversion intermediates reacted 65-99%: split(32-33)hPI 74%, des-(31,32)hPI 65%, split(65-66)hPI 78%, and des(64,65)hPI 99%. All serum values from 38 fasting healthy subjects were above the detection limit: median (range) 4.0 (2.1-12.6) pmol/L.

Proinsulin levels in newborn siblings of type 1 (insulin-dependent) diabetic children and their mothers

Elevated proinsulin levels have been observed in healthy first degree relatives of Type 1 (insulin-dependent) diabetic patients. This elevation could reflect a sequele after a previous attack on the beta-cells not necessarily leading to diabetes, or represent a family trait related to the development of diabetes. When cord plasma levels of proinsulin, insulin and C-peptide from 14 newborn siblings of Type 1 diabetic patients were compared with 21 newborn control siblings unrelated to diabetic subjects, no differences were observed. Neither were any differences observed between their mothers at delivery when comparing the same parameters. In cord plasma the proinsulin levels (median and range) were higher than those in plasma from 35 adult fasting women unrelated to diabetic subjects (10, 5-83 pmol/l vs 4, 2-33 pmol/l; p < 0.001) whereas the C-peptide levels (median and range) were lower (0.20, 0.11-0.56 nmol/l vs 0.37, 0.21-0.69 nmol/l; p < 0.001). No differences in insulin levels using a highly specific insulin assay were observed. The results suggest that newborn children have high proinsulin and low C-peptide levels unrelated to heredity of diabetes and that the previously described elevated proinsulin level observed in older first degree relatives of diabetic subjects occurs later in life.

Decreased beta-cell function in women with previous small for gestational age infants

Insulin, proinsulin and C-peptide responses to intravenous glucose (glucose infusion test, GIT) and insulin sensitivity were measured in women who previously and for unexplained reasons gave birth to small-for-gestational-age infants (SGA, n = 10) or appropriate-for-gestational-age infants (AGA, n = 11). Insulin sensitivity was evaluated by two different methods, somatostatin-, insulin- and glucose infusion test (SIGIT) and Bergman's minimal model method applied to the frequently samples intravenous glucose tolerance test. The two groups were comparable with regard to age, parity and body mass index. The SGA group exhibited significantly (p < 0.01) lower early (0-10 min) and late (10-60 min) insulin, C-peptide and proinsulin responses during GIT than were seen in the control AGA group. Insulin sensitivity evaluated by the two techniques was increased in the SGA group, significantly so only with the minimal model method. The insulin sensitivity index (Si) according to Bergman was 10.98 +/- 2.10 in the SGA as compared to 4.36 +/- 1.18 x 10(-4)min-1 x uU-1 in the AGA group (antilogged values +/- 95% confidence intervals). Early insulin response (GIT) and Si values were inversely correlated (r = -0.48, p < 0.05).

Identification of mycobacterial isolates by thin-layer and capillary gas-liquid chromatography under diagnostic routine conditions

The mycolic acid patterns of 75 strains of mycobacteria belonging to 46 different species were studied by thin-layer chromatography (TLC). Additionally, the mycolic acid pyrolytic cleavage products were determined by capillary gas-liquid chromatography (C-GLC). Eleven different patterns based on number, type and Rf values of the detected lipid spots were identified. The mycolic acid methyl ester profiles of clinical isolates were compared with those of reference strains. In this way, it was possible to relate these clinical isolates to mycobacterial groups defined by their mycolic acid profiles. The 11 patterns and the methods used are described in detail.

Nocturnal versus diurnal hormonal counterregulation to hypoglycemia in type 1 (insulin-dependent) diabetic patients

Asymptomatic hypoglycemia in IDDM patients seems to be more frequent during the night than during the day, with reported frequencies as high as 56%. Hormonal counterregulation to diurnal and nocturnal hypoglycemia was studied in 10 insulin-dependent diabetic patients without diabetic complications in order to test whether hormonal responses were lower at night than during daytime. A lower catecholamine response might imply less marked symptoms and therefore one reason why patients are not awakened by hypoglycemia. Blood glucose was stabilized to around 6 mmol/l by iv insulin infusion and hypoglycemia was induced by increasing the insulin infusion rate--in the night studies at 01.30, in the day studies at 08.00. Blood glucose nadirs were 1.5 +/- 0.4 (1.2-1.9) mmol/l at night and 1.9 +/- 0.3 (1.3-2.2) mmol/l during the day; in the three patients the nadirs were identical during both the night and day. One patient had no adrenaline response to daytime hypoglycemia. In general, nocturnal hypoglycemia elicited greater catecholamine responses correlated to the duration of hypoglycemia. Glucagon responses showed a great heterogeneity independently of diabetes duration and hypoglycemic level. Growth hormone secretion was reduced during the night study; however, no refractory periods were found after sleep-related growth hormone secretion.

IN CONCLUSION

counter-regulatory hormonal responses tend to be greater at night than during the day and do not explain why patients are not awakened by nocturnal hypoglycemia.