The Belgian PCB and dioxin incident of January-June 1999: exposure data and potential impact on health

In January 1999, 500 tons of feed contaminated with approximately 50 kg of polychlorinated biphenyls (PCBs) and 1 g of dioxins were distributed to animal farms in Belgium, and to a lesser extent in the Netherlands, France, and Germany. This study was based on 20,491 samples collected in the database of the Belgian federal ministries from animal feed, cattle, pork, poultry, eggs, milk, and various fat-containing food items analyzed for their PCB and/or dioxin content. Dioxin measurements showed a clear predominance of polychlorinated dibenzofuran over polychlorinated dibenzodioxin congeners, a dioxin/PCB ratio of approximately 1:50,000 and a PCB fingerprint resembling that of an Aroclor mixture, thus confirming contamination by transformer oil rather than by other environmental sources. In this case the PCBs contribute significantly more to toxic equivalents (TEQ) than dioxins. The respective means +/- SDs and the maximum concentrations of dioxin (expressed in TEQ) and PCB observed per gram of fat in contaminated food were 170.3 +/- 487.7 pg, 2613.4 pg, 240.7 +/- 2036.9 ng, and 51059.0 ng in chicken; 1.9 +/- 0.8 pg, 4.3 pg, 34.2 +/- 30.5 ng, and 314.0 ng in milk; and 32.0 +/- 104.4 pg, 713.3 pg, 392.7 +/- 2883.5 ng, and 46000.0 ng in eggs. Assuming that as a consequence of this incident between 10 and 15 kg PCBs and from 200 to 300 mg dioxins were ingested by 10 million Belgians, the mean intake per kilogram of body weight is calculated to maximally 25,000 ng PCBs and 500 pg international TEQ dioxins. Estimates of the total number of cancers resulting from this incident range between 40 and 8,000. Neurotoxic and behavioral effects in neonates are also to be expected but cannot be quantified. Because food items differed widely (more than 50-fold) in the ratio of PCBs to dioxins, other significant sources of contamination and a high background contamination are likely to contribute substantially to the exposure of the Belgian population.

Cytologic examination to detect clear cell adenocarcinoma of the vagina or cervix

OBJECTIVE

The aim of this study was to determine the sensitivity of cytopathologic examination for the detection of vaginal or cervical clear cell adenocarcinoma (CCA).

METHODS

Systematic collection in the Dutch automated nationwide pathology archive of all cytology and histology data of women with CCA, born in The Netherlands after 1947 was performed. All cytologic examinations within 2 years prior to histological diagnosis of CCA were included.

RESULTS

Ninety patients with CCA have been registered. Forty-nine of these patients had cytologic examinations prior to histology. Eighty-five percent of cervical CCAs were preceded by a positive cervical smear. One hundred percent of vaginal CCAs were preceded by a positive vaginal smear. Cervical smears are relatively insensitive to detect vaginal CCA. Vaginal smears were often omitted. Only 2 apparently false-negative smears were found. The mean numbers of smears in diethylstilbestrol (DES)-exposed and nonexposed women were minimally different: 1.0 and 0.8, respectively. This suggests an only modest impact of the awareness of DES as a risk factor. FIGO tumor stage I was preceded more frequently by cytology than the higher tumor stages.

CONCLUSION

The majority of CCA cases can be detected at an early stage by yearly clinical and cytological examinations, which must comprise cervical as well as vaginal sampling. Since CCA may also occur in postmenopausal women, for the purpose of secondary prevention of CCA regular cytologic examinations of DES-exposed women must be continued after menopause.

How to get serious answers to the serious question: "How have you been?": subjective quality of life (QOL) as an individual experiential emergent construct

Medical, scientific and societal progress has been such that, in a universalist humanist perspective such as the WHO's, it has become an ethical imperative for the primary endpoints in evidence based health care research to be expressed in e.g. Quality Adjusted Life Years (QALYs). The classical endpoints of discrete health-related functions and duration of survival are increasingly perceived as unacceptably reductionistic. The major problem in 'felicitometrics' is the measurement of the 'quality' term in QALYs. That the mental, physical and social domains, each containing many dimensions and items, all contribute to QOL is uncontroversial. What is controversial, is the weight of the different dimensions in overall QOL. It has been shown to be very different between different patient populations. In human individuals, assuredly complex systems, the many dimensions and items of QOL observably interact, probably sometimes in chaotic ways. In these conditions, the weights of isolated items in individuals become for all practical purposes meaningless. Therefore, the much used multi-item questionnaires at best describe, but do not evaluate QOL, neither in individuals, nor in populations. For example, allergic patients treated with cetirizine scored better than those on placebo on all dimensions of the SF-36, a standard QOL questionnaire. Here there is no serious doubt that the treatment improved QOL, because it is highly unlikely that any important dimension on which the patient groups would have scored otherwise is missing in the SF-36. However, whether piracetam treatment of acute stroke, which improved the surrogate endpoints neurological and functional scores, also improved QOL is plausible, but will be proven only when comprehensive QOL measurement will have been done. And suppose in randomised populations of end-stage metastatic solid cancer patients, one would compare palliative last-line chemotherapy with only palliative care, and one would, as can be expected, find no significant differences in average survival, and chemotherapy superior for the mental domain, but inferior for the physical comfort domain: we would not know which treatment, on aggregate, would be the better. The problem is that QOL is an individual and emergent construct, the resultant of a great many interactions, and of a different order than its contributing components. Overall QOL can therefore best be captured only as the Gestalt of a global self-assessment. Just as people in everyday life, while acting under uncertainty, make global assessments all the time, so they can seriously answer the serious question: 'How have you been?' A solemn, practical, non peer-relativistic, non-cultural, experiential, and well tolerated way to obtain such responses is Anamnestic Comparative Self Assessment (ACSA), in which the subjects' memories of the best and the worst times in their life experience define their individual scale of QOL. ACSA is thus both exquisitely idiosyncratic, and yet can in a universalist humanistic perspective be considered generic. Using both a multi-item questionnaire and a global assessment allows by one logistic regression, to estimate the weights of the dimensions and items in populations, and thus identify those whose improvement would most contribute to the QOL of the greatest number. A combined approach to measurement of QOL is necessary to maximise the utility of QOL interventions.

Similia similibus obscurantur: the pharmacological clinical activity bias I. A prototype model to correct a disease-drug interaction leading to misestimations of drug-attributable side effects

Drugs have side effects that manifest as signs or symptoms which are sometimes undistinguishable from signs or symptoms of active disease. The conventional approximation of the rate of side effects of drugs is by subtracting the rate of signs and symptoms in the placebo group from that in the drug group. This measures net side effects and is adequate in studies with healthy volunteers, in which no interaction between drug and disease exists. For ethical and practical reasons, however, volunteer studies cannot be large and the frequency of non-rare side effects must be estimated in large-scale clinical trials. In the latter, biasing drug disease interactions may occur. We report on such a hitherto undescribed interaction: the pharmacological clinical activity bias. If one is interested in estimating not the net, but the direct or intrinsic, ie, drug-attributable side effects, the conventional approximation is biased whenever, in clinical trials, both of two conditions apply. The first is that the variable on the scale of which a sign or symptom is recorded as a putative side effect, is also in the absence of drug affected by uncontrolled disease. The second is that the drug has pharmacological clinical activity (A) on that sign or symptom, thus reducing the contribution of disease (D) to what is measured. In this case the drug affects the variable under study both directly, through its intrinsic side effect, and indirectly, through its clinical activity, and the rate of attributable side effects differs from the rate of net side effects as calculated by the conventional approximation. We present a simple deterministic model, which assumes that disease remains stable if untreated, additivity of the relative contributions of drug, placebo and disease to the total rate of the sign or symptom, and no other interaction between intrinsic properties of the drug and active disease than pharmacological clinical activity. This theoretical model quantifies the bias as DO(Ad-Ap), in which DO is the baseline frequency of the sign or symptom in the studied patients, and Ad and Ap are the intrinsic clinical activities of drug and placebo, respectively, on the sign or symptom under study. The model confirms that the conventional approximation of drug side effects is unbiased only in healthy volunteers or with drugs devoid of clinical activity. Without correction by such a model, any clinical activity of the drug or manifestation of active disease will cause the conventional approximation of side effects to be biased. This may manifest as artifacts such as attribution of a side effect when there is none, and as under- or overestimation, pseudotachyphylaxis, or pseudo-delayedness of attributable side effects.

Effect of timing of antihypertensive therapy on glomerular injury: comparison between captopril and diltiazem

Recent studies have suggested that the progression of experimental chronic renal disease may be prevented by early use of antihypertensive drugs. It is unclear, however, whether such therapies may also affect established and progressive renal disease. In the present study we compared the effects of captopril (CEI) and diltiazem (CCB), started either at week 10 or at week 24 on the evolution of adriamycin nephropathy (AN). Rats were studied at weeks 7, 16, 24, 32, and 38 of the disease. None of the treatments influenced the development of nephrotic range proteinuria. The use of CCB from week 10 was even associated with increased proteinuria. The moderate hypertension of ADR rats was reduced to the same degree with both drugs. Inulin clearance (GFR) was significantly reduced in all ADR rats. However, in ADR rats treated with CEI from week 10 and in those treated with CCB from week 24, the GFR was relatively higher. Glomerular injury, evaluated by semiquantitative methods, was not ameliorated by CEI treatment. Earlier CCB treatment (week 10) worsened glomerular lesions, whilst CCB treatment initiated at week 24 reduced significantly the degree of mesangial expansion and focal glomerular sclerosis. We conclude that, in addition to their common antihypertensive action, the specific effect of drug therapy seems to be crucially time dependent.

The role of fluorinated pyrimidine analogues in the induction of the in vitro expression of the fragile X chromosome

The modes of action of 5-fluoro-2'-deoxyuridine (FdUrd) and 5-fluoro-2'-deoxycytidine (FdCyd) were studied in PHA-stimulated lymphocytes from normal volunteer donors and a fragile X patient. In both cell types, FdUrd and FdCyd inhibited cell proliferation at concentrations of 3 x 10(-8) M. Thymidylate synthetase was identified as the decisive target for the action of both FdUrd and FdCyd, as judged from the following observations: First, addition of thymidine to the culture medium was able to counteract both FdUrd and FdCyd toxicities, whereas addition of dCyd had no observable effect. Second, inhibition of the in situ thymidylate synthetase activity measured as an increase in the level of [3H]-dThd incorporation coincided with the inhibition of cell proliferation. Third, the inhibition of the thymidylate synthetase-dependent incorporation of [3H]-dUrd into newly synthesized DNA coincided with the inhibition of cell proliferation. The effects of FdUrd and FdCyd on the in vitro expression of fragile site Xq27 of fragile X chromosomes was shown to be based on the depletion of the intracellular pool of thymidine-5'-monophosphate (dTMP), as judged from the following observations: First, both the FdUrd- and FdCyd-dependent induction of site Xq27 coincided with the antiproliferative effects of the respective fluoropyrimidines. Second, addition of thymidine (dThd) to the culture medium both prevented the expression of site Xq27 and neutralized the cytotoxicity of FdUrd and of FdCyd. On the basis of these findings, we provide further evidence for the concept that the fragile X site is located in an AT-rich region.

Reversible renal failure due to psychogenic urinary retention

A case of advanced, reversible renal failure due to psychogenic urinary retention occurring in a 17 year old female, is reported. The diagnosis of psychogenic urinary retention was made on the basis of existent florid psychopathology and the concomitant exclusion of an organic cause. Family psychodynamics are discussed. Psychosocial intervention led to a resumption of normal micturition, the disappearance of the urinary retention with resultant improvement of renal function.

5-fluorouracil and 5-fluoro-2'-deoxyuridine follow different metabolic pathways in the induction of cell lethality in L1210 leukaemia

The mode of action of 5-fluorouracil (FUra) and 5-fluoro-2'-deoxyuridine (FdUrd) on L1210 leukaemia has been studied. It is shown that FUra and FdUrd follow different routes of metabolism and have different targets with respect to their cytotoxic activity. FUra is converted to 5-fluorouridine-5'triphosphate ( FUTP ), which is incorporated into nascent RNA. FdUrd is converted to 5-fluoro-2'-deoxyuridine-5'-monophosphate (FdUMP), which inhibits the de novo synthesis of 2'-deoxythymidine-5'-monophosphate (dTMP). Conversion of FUra to FdUMP does occur, but this phenomenon does not contribute to the final cytotoxic effect. No conversion of FdUrd to FUra has been detected.

In vitro assessment of cytotoxic agents in murine cancers: comparison between antiproliferative and antimetabolic assays

Different methods were compared for the in vitro evaluation of the therapeutic effects of the antineoplastic agents doxorubicin, cisplatin, fluorouracil, and vinblastine sulfate in a model system of murine tumor cell lines consisting of L1210 leukemia, P815 mast cell leukemia, and B16 melanoma. Excellent correlations were found with the in vivo effects with the use of a soft agar clonogenic assay, irrespective of the method of growth assessment (i.e., visual colony counting or incorporation of tritiated thymidine in proliferating colonies). Drug effects on the proliferation of tumor cell lines in liquid medium frequently led to an overestimation or underestimation of the actual in vivo effects. Direct incorporation of the radiolabeled precursors thymidine, uridine, and leucine after pretreatment with drugs always led to the prediction of resistance and was therefore considered unreliable.

Rate of DNA synthesis in exponentially growing cell lines in the presence and absence of antimetabolites

Experimental tumor cell lines were used to show that in the presence of 5-fluorodeoxyuridine (FdUrd), the rate of DNA synthesis remains unaltered as long as a saturating concentration of thymidine is present. This unimpeded rate of DNA synthesis in combination with FdUrd-blocked de novo thymidylate synthesis makes it possible to accurately measure the total rate of increase of DNA using tritiated thymidine of known specific activity. The observed amount of incorporated tritiated thymidine is in excellent agreement with the calculated theoretical maximal incorporation in cultures with exponentially increasing DNA and cell number.

Parathyroid hormone secretion and responsiveness to parathyroid hormone in primary hypomagnesemia

Parathyroid function was studied in two infant sisters with primary hypomagnesemia while they were both hypomagnesemic and hypocalcemic. In one of the infants, plasma immunoreactive parathyroid hormone (iPTH) was elevated, the calcemic response to exogenous parathyroid hormone (PTH) was absent, and the phosphaturic response was normal. Restoration of serum magnesium with i.v. magnesium corrected the hypocalcemia, with no further rise of plasma iPTH. In the other infant, plasma iPTH was undetectable, and exogenous PTH produced both phosphaturic and calcemic responses. Normalization of serum magnesium with i.v. magnesium resulted in a prompt release of endogenous PTH and correction of the hypocalcemia. These findings suggest that, in the first patient, hypocalcemia was associated with lack of response of the bone to both endogenous and exogenous PTH, while in the second patient, hypocalcemia was associated with inhibition of PTH release and a normal calcemic response to exogenous PTH. The factors that determine whether magnesium deficiency will result in inhibition of PTH release, in a lack of response of the bone to endogenous and exogenous PTH, or both, remain to be clarified.

Minimal-change nephropathy and malignant thymoma

A 56-year-old man had fever, precordial pain, and a mediastinal mass. The mass disappeared two months later and the patient remained asymptomatic for 2 1/2 years. At that time a full-blown nephrotic syndrome developed, with minimal-change glomerulopathy. The chest x-ray film showed the reappearance of a giant mediastinal mass. On biopsy of the mass, malignant thymoma was diagnosed. Association between minimal-change disease and Hodgkin's disease is well known, while the association with malignant thymoma has not been previously reported. The relationship between malignant thymoma and minimal-change disease is discussed, and a possible pathogenic mechanism involving cell-mediated immunity is proposed.

[Leiomyoma of the small bowel with hypercalcaemia: presence of a substance with parathormone activity (author's transl)]

A leiomyoma of the small bowel produced laboratory features of hyperparathyroidism which disappeared promptly after tumour resection. Hypercalcaemia, hypophosphatemia, hyperchloremia, elevated chloride/phosphorus ratio, increased urinary cyclic AMP, and blood levels of immunoreactive parathormone were present. Electron microscopy showed dense round granules in the tumour cells.

DNA synthesis and proliferation of human lymphocytes in vitro. II. Characterization of the DNA newly synthesized after phytohemagglutinin stimulation

DNA newly synthesized by phytohemagglutinin-(PHA) stimulated human lymphocytes has been analyzed for the possibility that all DNA synthesis may not represent premitotic genome duplication. Equilibrium density gradient characterization of bromodeoxyuridine-(BUdR) substituted DNA demonstrates semi-conservative DNA replication, without evidence for repair synthesis. Experiments to detect selective replication (amplification) of a portion of the DNA involved measurement of reassociation kinetics as well as measurement of the kinetics of BUdR appearance in prelabeled DNA. The presence of large quantities of amplified DNA has been excluded, although amplification cannot be ruled out completely by these techniques. Finally, the kinetics of DNA release from dead lymphocytes is characterized, and factors tending to reduce the complexity of released, labeled DNA are identified.

DAN Synthesis and Proliferation of Human Lymphocytes in Vitro

The response of human lymphocytes to phytohemagglutinin (PHA) stimulation was assessed in detailed kinetic studies, in order to define conditions permitting and regulating proliferation. By utilizing live and dead cell counts, cell cycle characterizations, and calculations of rates of entry into S phase and mitosis, it was demonstrated that dilute culture conditions (2 × 105 cells/ml) enable lymphocytes to proliferate for a period of 5 or 6 days. Although cell division occurs in concentrated cultures (2 × 106 cells/ml), net proliferation is not demonstrable due to extensive cell death and earlier decay in the proliferative response. It is projected that without cell death the cell count would rise more than 6-fold in a dilute culture and 2-fold in a concentrated culture under these growth conditions. The kinetic analyses did not demonstrate separate PHA dose thresholds for blastogenesis and entry into S phase. High doses of PHA stimulated a suboptimal response by causing excessive cell death without reducing initial entry into the cell cycle. These results provide a kinetic explanation for the frequent observation of little net proliferation despite substantial 3H-thymidine incorporation in PHA-stimulated lymphocyte cultures. Cell death is identified as a parameter that must be considered in the interpretation of in vitro lymphocyte stimulation studies, and methods for quantifying the role of cell death are demonstrated.

DNA synthesis and proliferation of human lymphocytes in vitro. I. Cell kinetics of response to phytohemagglutinin

The response of human lymphocytes to phytohemagglutinin (PHA) stimulation was assessed in detailed kinetic studies, in order to define conditions permitting and regulating proliferation. By utilizing live and dead cell counts, cell cycle characterizations, and calculations of rates of entry into S phase and mitosis, it was demonstrated that dilute culture conditions (2 X 10(5) cells/ml) enable lymphocytes to proliferate for a period of 5 or 6 days. Although cell division occurs in concentrated cultures (2 X 10(6) cells/ml), net proliferation is not demonstrable due to extensive cell death and earlier decay in the proliferative response. It is projected that without cell death the cell count would rise more than 6-fold in a dilute culture and 2-fold in a concentrated culture under these growth conditions. The kinetic analyses did not demonstrate separate PHA dose thresholds for blastogenesis and entry into S phase. High doses of PHA stimulated a suboptimal response by causing excessive cell death without reducing initial entry into the cell cycle. These results provide a kinetic explanation for the frequent observation of little net proliferation despite substantial 3H-thymidine incorporation in PHA-stimulated lymphocyte cultures. Cell death is identified as a parameter that must be considered in the interpretation of in vitro lymphocyte stimulation studies, and methods for quantifying the role of cell death are demonstrated.