[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).

The influence of early postoperative intraperitoneal chemotherapy on human wound healing.

Cell ingrowth, hydroxyproline accumulation, and mRNA expression of collagen I were measured in two polytetrafluoroethylene grafts implanted subcutaneously at the time of colorectal cancer surgery to evaluate the influence of early postoperative chemotherapy on human wound healing. Eleven patients treated with intraperitoneal 5-fluorouracil and intravenous folinic acid Days 1-6 after operation were compared with 15 patients who underwent surgery alone. At 1 week, chemotherapy-treated patients had accumulated less hydroxyproline (mean 0.35 +/- 0.33 micrograms/cm) compared with untreated patients (mean 0.73 +/- 0.37 micrograms/cm, P < 0.05). By 2 weeks, the hydroxyproline content had increased sixfold in the chemotherapy group (P < 0.01) and threefold in the nonchemotherapy group (P < 0.01) and there was no difference between the groups. Cell and connective tissue ingrowth and total RNA content did not differ between the groups at any point in time, but at 1 week the mRNA expression of collagen I was higher in the chemotherapy group (P < 0.05). These results indicate that collagen accumulation in human subjects is reduced during a short course of postoperative chemotherapy and normalizes after the end of treatment.

Selenium in malnourished Sudanese children: status and interaction with clinical features.

Plasma selenium (Se), haemoglobin (Hb) and packed cell volume (PCV) were measured in 53 malnourished Sudanese children, age 6-36 months, and 11 children who had tuberculosis. Twelve healthy well-nourished children served as controls. The mean (+/- SD) plasma Se (mg/kg) was 0.05 (0.036), 0.070 (0.040), 0.063 (0.015), 0.73 (0.012), 0.082 (0.014) in children with kwashiorkor/marasmic kwashiorkor (oedematous group), marasmus, tuberculosis and healthy controls. The mean Se level in the various groups showed a significant difference (p < 0.002). Whereas the oedematous group differed significantly from the rest, there was no difference between the means of the marasmic, underweight, tuberculosis patients and controls. The mean plasma albumin (+/- SD) in oedematous group was 19.6 (6.6) g/l and ranged between 22.6 (5.0) and 33.1 (3.0) in the other groups. A significant positive correlation was found between plasma Se level, albumin, Hb and PCV (respectively, r = 0.46, p < 0.0001; r = 0.37, p < 0.001; r = 0.36, p < 0.002).

Fragments of chromogranin A are present in the urine of patients with carcinoid tumours: development of a specific radioimmunoassay for chromogranin A and its fragments.

Chromogranin A is a well-known protein constituent in granules of neuroendocrine cells. It is also known that plasma levels of chromogranin A increase considerably in patients with neuroendocrine tumours and thus chromogranin A is used as a marker for these tumours. In the present study, we have shown that fragments of chromogranin A are excreted into the urine in some patients with carcinoid tumours. The chromogranin A molecule appeared in the urine N-terminally cleaved at amino acid positions 116 and 210, which are previously reported cleavage sites of the molecule. The fragments identified were mainly of about 35 kDa in size. The unprocessed chromogranin A molecule was not excreted in the urine. Five out of 40 patients excreting the fragments had slight tubular dysfunction in the kidneys. We also showed that these renally excreted split products of chromogranin A were immunogenic and could be used for production of antibodies against chromogranin A. These antibodies were used both for immunocytochemistry and for the development of a specific and sensitive radioimmunoassay for chromogranin A and its fragments. Measurements of plasma chromogranin A by radioimmunoassay appeared to be a better marker for tumour growth than were measurements of chromogranin A in the urine.

A Nordic reference serum suitable for use as trueness control in the clinical routine laboratory.

The described reference serum is characterized by: liquid human serum at "normal" level stored in frozen state at -80 degrees C; minimum damage of proteins; aseptic preparation; cryoprecipitate and excess fibrin removed; serum cleared by ultracentrifugation; pH at 7.2-7.6; available in sealed glass ampoules with inert gas (one ml serum in each); specified components among most frequently analyzed analytes; homogeneity assured and stability monitored; produced under strict rules for good manufacturing practices (GMP). The assigned values are traceable to reference measurement procedures and reference materials of highest achievable metrological level; according to the present proposal the maximum allowable uncertainty of the assigned value is based on biological variation (shared common reference intervals); the uncertainty should ideally not exceed 1/5 of the maximum allowable bias of results obtained on patients samples (even 1/2 would theoretically be acceptable and, for a practical guide approximately < 1% may suffice). The present document provides some guidance of how the reference serum could be established in practice. The document also indicates the use of the material and further extension of the concept. The present work is done as a NORDKEM project.

A hyaluronan-loading test applied to patients with liver and joint diseases.

The serum hyaluronan disappearance data, after an intravenous bolus injection of hyaluronan, were evaluated in terms of model-based parameters. The loading test was performed in 10 healthy persons (basal serum hyaluronan concentration, C0, 24.9 +/- 8.9 micrograms/l [mean +/- S.D.]), 6 patients with joint disease (62.3 +/- 41.1 micrograms/l) and 19 patients with liver disease (206 +/- 214 micrograms/l). The highest maximum Michaelis-Menten elimination rate (Vmax = 287 +/- 86 micrograms/min) was found in patients with joint disease, significantly higher than in healthy persons (Vmax = 179 +/- 16, P = 0.0015) and in patients with liver disease (Vmax = 149 +/- 59, P = 0.0002). C0 and Vmax were evaluated as discriminants for assessment of residual liver function. In patients with liver disease C0 correlated with liver function score (r = 0.875, P < 0.0001) and serum albumin concentration (r = -0.813, P < 0.0001). The Vmax parameter did not correlate with conventional liver function tests or with the liver score but a significantly negative correlation of Vmax with C0 was found in patients with liver disease. A combination of the C0 level and the Vmax parameter was found to discriminate between healthy persons, patients with joint disease and patients with liver disease and should be of benefit in separating patients, with or without elevated serum hyaluronan levels, into groups having increased influx or reduced elimination, respectively, of circulating hyaluronan.

[Results of multicenter evaluation of reagents for determination of sodium, potassium and chloride ions using enzyme activation]. / Ergebnisse der multizentrischen Evaluierung von Reagenzien zur Bestimmung von Natrium-, Kalium- und Chloridionen mittels Enzymaktivierung.

We present the results of a multicentre evaluation with Boehringer Mannheim/Hitachi instruments of new "enzymatic" methods for the determination of Na+, K+, and Cl- in serum or plasma. The between-day coefficient of variation was less than 1.4% (Na+), less than 2.6% (K+) and less than 1.7% (Cl-). The linear range of the assays were at least 80 to 200 mmol/l (Na+), 1.5 to 17 mmol/l (K+) and about 30 to at least 200 mmol/l (Cl-). The comparisons with routine flame atomic emission spectrometry and coulometry showed a satisfactory agreement of the test results. The "enzymatic" assays are insensitive to even grossly elevated levels of bilirubin and lipids (sodium, potassium, and chloride assays), NH4+ (potassium assay) and amylase (chloride assay). Interference by various drugs was not detected. Since the new methods can easily be adapted to photometric clinical chemistry instruments, they represent a valuable alternative to the use of ion-selective electrodes, flame atomic emission spectrometry and coulometry.

Normas para avaliaçäo de fitas reativas, exemplificadas pela fita reativa utilizada na análise das concentraçöes de albunina e glicose na urina / Rules for avaliation of reagent strips, that nas exemplified by reagent strips utilized in analisy of albumin and glucose concentrations in urine

Fitas reativas säo freqüentemente usadas em laboratórios de análises clínicas bem como em outros meios. No presente relato é apresentado um esquema que permite uma descriçäo reproduzível do comportamento das fitas reativas, exemplificado com fitas usadas na análise estimativa de albumina e glicose urinária. Condiçöes experimentais que säo particularmente importantes para estes componentes säo fornecidos. Itens adequados e necessários que devem ser incluidos na descriçäo dos resultados de uma avaliaçäo säo enumerados. As normas podem ter aplicaçäo e descriçäo de testes, com um número limitado de resultados possíveis

Guidelines for evaluation of reagent strips. Exemplified by analysis of urine albumin and glucose concentration using visually read reagent strips. International Federation of Clinical Chemistry, Scientific Division.

Reagent strips are frequently used in the practice of laboratory medicine as well as outside the professional laboratories. In the present report, a scheme is presented which allows a reproducible description of the performance of reagent strips. This is exemplified using strips intended for estimation of urinary albumin and glucose. Experimental conditions that are particularly important for these components are given. Suitable and necessary items which should be included in the protocol presenting results of an evaluation are listed. The guidelines might have general applicability in evaluation and description of tests with a limited number of possible results.

C-peptide but not insulin concentrations are related to the serum lipoprotein levels during insulin treatment of non-insulin-dependent diabetes mellitus (NIDDM) patients.

In 21 non-insulin-dependent diabetic patients with secondary drug failure, once-daily long-acting insulin lead to a moderately improved metabolic control. At the conclusion of the study (eight months) the fasting blood glucose and HbA1c concentrations were significantly decreased, but the postprandial blood glucose concentrations in the afternoon were unaltered. The peripheral insulin sensitivity, as measured by the intravenous insulin tolerance test, and the lipoprotein lipase activity in adipose and skeletal muscle tissue had increased. After initiation of insulin therapy there was a transient decrease of the fasting and glucagon-stimulated C-peptide concentrations. The very low density lipoprotein lipids and apolipoprotein B, A-I and A-II were also reduced transiently. The only significant difference in lipoprotein composition at eight months compared with on admission, was an increased cholesterol and decreased triglyceride concentration in the high density lipoproteins. There were significant relationships between the C-peptide, but not the peripheral insulin, concentrations and the serum lipid concentrations. This may indicate that high peripheral insulin concentrations after administration of exogenous insulin may affect the hepatic lipoprotein production less than the portal insulin concentrations mainly derived from endogenous production.

Amino acid concentrations in cerebrospinal fluid in presenile and senile dementia of Alzheimer type and multi-infarct dementia.

Free amino acid levels were measured in cerebrospinal fluid (CSF) from demented patients (D, n = 30) suffering from presenile and senile dementia of Alzheimer type (PDAT, n = 7; SDAT, n = 9), multi-infarct dementia (MID, n = 14) and a reference sample group consisting of young neurotic patients (R, n = 16). Comparing the amino acid levels in the dementia subgroups, significantly higher alanine, methionine, phenylalanine and tyrosine levels were found both in MID and SDAT vs. PDAT. No difference was seen between SDAT and MID. Compared to the reference sample group, higher glycine levels were found in each dementia subgroup; higher alanine, methionine and ornithine levels in MID, and SDAT; and higher phenylalanine levels in MID. In PDAT the level of tyrosine was lower. Coefficients of correlation were calculated between amino acid levels and age, and the findings in the reference sample groups were divergent from those observed in dementia. The differences observed are discussed in terms of amino acid, carbohydrate and neurotransmitter metabolism.

Early changes of some serum proteins and metals in diabetic children.

Serum concentrations of prealbumin, albumin, orosomucoid, magnesium, zinc and calcium were studied in 30 children with newly diagnosed IDDM aged 3-15 years, during the first two years of the disease, and in 44 healthy control children. On admission serum prealbumin was significantly lower in IDDM children (149 +/- 48 mg/l) (M +/- SD) than in healthy controls (194 +/- 39 mg/l) (p less than 0.001). During the two years follow-up prealbumin increased significantly, but did not reach the level of healthy controls. Serum albumin was slightly increased at diagnosis (p less than 0.01), but later decreased significantly (p less than 0.01). Orosomucoid concentrations did not differ between diabetics and controls. Serum magnesium was initially within the reference interval but later decreased, and after 2 years of IDDM it was highly significantly reduced (p less than 0.001). Serum zinc was significantly reduced in IDDM children at diagnosis (p less than 0.001), but was within the reference interval after one and 2 years. Serum calcium was increased in the IDDM group at diagnosis (p less than 0.01), but later normalized. It is concluded that in early IDDM there is a decrease in serum prealbumin and albumin, and serum magnesium decreases progressively, while serum zinc is only transiently reduced.

Biochemical changes and endocrine responses in cystic fibrosis in relation to a marathon race.

Biochemical changes and endocrine responses during the New York Marathon (42195 m) were investigated in three 18-year-old male adolescents with cystic fibrosis (CF) and three healthy men who accompanied the CFs during the race. The ambient temperature was 20 degrees-28 degrees C and the relative humidity 98%-75% during the run. The CF patients, who had Shwachman scores of 60, 85 and 95 completed the run without major problems in 6.10, 4.42, and 4.32 h, respectively. Serum concentrations of Na and Cl decreased slightly, but the values were still within normal range. Na and Cl excretions in the urine decreased to very low levels in the CF adolescents during the run. All the other biochemical changes were similar to the changes in the controls. Aldosterone concentration increased to a higher level and maintained this increase for a longer time after the race in the CFs. Testosterone concentration decreased more in the CFs during the race compared with the controls. Growth hormone concentration showed individually varying changes in response to the exercise. This study demonstrates that patients with CF may participate in strenuous prolonged exercise even in humid and hot conditions, without untoward effects. The observed differences in hormonal responses to exercise might be explained by differences in age, training status, and relative exercise intensity rather than by hormonal or other disturbances in CF.

Lipoprotein composition of human suction-blister interstitial fluid.

Interstitial fluid (IF) was obtained in 27 apparently healthy subjects (12 males, 15 females) by applying mild suction (200-250 mm Hg) on the skin either on the midvolar forearm or on the paraumbilical region of the abdomen. The IF concentrations of lipids and apolipoproteins (apo) were studied and compared with those of serum (S). The mean ratio between interstitial fluid and serum (IF/S ratio) varied from 0.14 for forearm apoE to 0.29 for apoA-II on the abdomen. This ratio was consistently lower for apoE, C-II, C-III, and B than for apoA-I and A-II, and significantly lower on the arm than on the abdomen for all apolipoproteins studied. The IF/S ratios showed marked variations among individuals. However, interstitial fluid apolipoprotein concentrations at different blister sites were highly correlated within each individual. Studies with agarose gel electrophoresis and density gradient ultracentrifugation revealed that large triglyceride-rich particles were virtually lacking in interstitial fluid and that the relation between the low density lipoproteins (LDL) and high density lipoproteins (HDL) was shifted towards a greater proportion of HDL. The lipoprotein distribution in the HDL range of interstitial fluid differed from that of serum showing one maximum at a density of about 1.070 g/ml (serum HDL2 about 1.090 g/ml) and one at a density of 1.130-1.140 g/ml (serum HDL3, 1.110-1.120 g/ml). The former subfraction contained most of the lipoprotein-bound apoE while the latter contained the major part of apoA-I and apoA-II. Studies of the lipoproteins of interstitial fluid may add to our understanding of the development of atherosclerosis and xanthomatosis and may also provide valuable information on the permeability of the capillary membrane in normo- and pathophysiological states.

Saliva and sweat secretion in man during a one-hour calcium clamp.

The effect of a 1-h calcium infusion, directly regulated to obtain and maintain a predetermined blood calcium level ('calcium clamp'), on the composition of parotid saliva, mixed saliva, and sweat was determined in healthy volunteers. An increase in amylase content of the parotid saliva under hypercalcaemic conditions was observed, but the 'calcium clamp' had no effect on flow rate, total and ionized calcium, sodium, potassium, and phosphate levels as well as pH in parotid and mixed saliva. The sweat calcium concentration was negatively correlated with sweat rate, in contrast to sodium and chloride concentrations. Increasing serum calcium levels did not affect ionic composition of the sweat and sweat flow rate.