[How does model- and situation-specific lack of knowledge affect causal inferences?]. / Wie wirken sich modell- und situationsspezifisches Unwissen auf das Ziehen kausaler Schlüsse aus?

A model proposed by Thüring (1991) for inferences based on causal knowledge was empirically tested. According to this model, two variables affect the certainty with which a causal inference is concluded: insufficiency (model-specific uncertainty) and ambiguity (situation-specific uncertainty). Within an experiment these two variables were manipulated. Both had a very significant (p < .01) influence on causal inferences. In respect to its quantity, variation of ambiguity had the effect predicted in the model. Concerning insufficiency, distinct differences between predicted and empirical ratings were found. Reasons for these deviations and model modifications resulting therefrom are discussed.

[Sudden infant death]. / Plötzlicher Kindstod.

Sudden infant death [SID] is defined as the "sudden death of an infant under one year of age that remains unexplained after a thorough case investigation, including performance of a complete autopsy, examination of the death scene and the review of the clinical history". This definition, given by the National Institute of Child Health and Human Development in the USA. recognized SID as a diagnostic entity, however, SID remains a pathological diagnosis of exclusion. SID-cases are divided into three categories: group 1 in which autopsy does not reveal any cause of death, group 2 in which postmortem findings are not sufficient to be the cause of death; group 3 in which the death is adequately explained, is classified as "non-SID". The purpose of the study was to analyse the situation about SID over a 25-year period, from 1969 through 1993, looking for changes in frequency and developmental trends. The study includes 364 SID-infants which were examined according to a standard method. Histological, microbiological, virological and immunological studies were performed and data of the death scene investigation and of the clinical history were collected, 284 infants who had died due to clinical diseases served as one control group, a second group consisted of 6397 newborns of the city of Zürich. Of the SID-infants, almost every third infant [29%] was grouped in group 1, more than half of the infants [52%] with signs of mild infections in group 2, whereas almost every fifth child [19%] was grouped in group 3. With regard to epidemiological parameters the peak of mortality was found at about three months of age; the percentage of boys and twins, of third and later born infants was higher compared to the general population. SID probands were born twice as often in October as in March. The percentage of mothers of first, second and third born SID-infants at an age younger than 20, 22 and 24 years was higher compared to the general population. All these parameters were also found in group 3. The risk of familial recurrence in group 1 and group 2 was 0.8%. Between 1969 and 1993 the rate of SID deaths dropped from 1.1 to 0.9 per thousand live births, whereas SID as a percentage of postneonatal mortality increased to 34 per cent.

Medium-chain acyl-CoA dehydrogenase deficiency does not correlate with apparent life-threatening events and the sudden infant death syndrome: results from phenylpropionate loading tests and DNA analysis.

Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency is the most common inherited disorder of fatty acid metabolism and typically presents in early childhood as potentially fatal hypoketotic, hypoglycaemic crisis often associated with Reye-like symptoms. Re-investigations of cases of sudden infant death syndrome (SIDS) have revealed in some instances a deficiency of MCAD, suggesting that this metabolic disorder may lead to sudden infant death without prior clinical symptoms. In the present study, we examined 142 infants who had suffered from an apparent life-threatening event (ALTE) or were otherwise considered at risk for SIDS for MCAD deficiency by phenylpropionate loading. In no case excretion of phenylpropionylglycine, the hallmark of MCAD deficiency, was increased. In contrast, 3 out of 55 children with symptoms of metabolic disorders showed increased phenylpropionylglycine excretion, and in all three cases MCAD deficiency was confirmed by DNA analysis. In addition, we investigated 142 cases of sudden unexplained child death and 100 control subjects for the A985G mutation in the MCAD gene which is associated with about 98% of enzyme deficiencies. We found one case of heterozygosity each in the patient and control group. Our data indicate that MCAD deficiency is not a major cause of ALTE and, in agreement with results from similar studies in other countries, its frequency is not increased in children who died of SIDS.

Morphologic variations in 180 cases of sudden infant death and 180 controls.

The incidence of morphologic variations (MVs) was investigated in 180 infants who died unexpectedly and suddenly and in 180 age-matched nonsuddenly deceased infants. The same person (G.M.) performed a full postmortem and histologic examination on all of the infants, none of whom had significant malformations. The test group (TG) consisted of 146 infants whose death was unexplained, whereas group 3 (G3) consisted of 34 infants with adequately determined causes of death. The principal findings in the control group were prematurity, inflammatory and metabolic diseases, tumors, and traumatic lesions. MVs were present in 62% of the TG infants, in 47% of the G3 children, and in 22% of the controls. The differences between the TG and G3 on the one hand and the controls on the other are statistically significant (p < 0.001 and 0.05, respectively). In the TG, anomalies were twice, dysplasias three times, and dysmorphisms four times as common as in controls; in G3, four times as many dysplasias and dystropics were found as in controls. In the TG, 23% of the MVs were multiple as compared with 9% in G3 and 5% in controls. The pattern of distribution was not confined to certain organs. Among the relative high percentage of dysplasias, the large number of neuroblastomas is striking.

Continuous microbiological and pathological study of 70 sudden and unexpected infant deaths: toxigenic intestinal clostridium botulinum infection in 9 cases of sudden infant death syndrome.

As part of a programme to exclude infection as the cause of death in infants who died suddenly and unexpectedly necropsies were carried out on 70 such infants. In 11 cases (15%), a pathological diagnosis could be made at necropsy; in 9 of these, causative bacteria or viruses were found. The 59 cases in which the cause of death could not be found had histological features characteristic of sudden infant death syndrome (SIDS). Botulinum toxin was found in 9 SIDS cases (15%). 8 of these infants had botulinum toxin and organisms of different types (A, B, C, F, G) in the contents of the ileojejunum or colon. 4 of them also had toxin in the serum. No botulinum toxin or organisms were found in the 11 infants who died of identified causes or 18 other infants who died in hospital of known causes.

[Sudden infant death. Epidemiological factors in unexplained, partially or insufficiently explained causes of death]. / Plötzlicher Säuglingstod. Epidemiologische Erhebungen bei nicht, teilweise oder hinreichend erklärbarer Todesursache.

Epidemiologic investigations were carried out on 185 infants, who died suddenly and on whom autopsies were performed. 53 infants died a "true sudden infant death", for 90 infants death was partly, and for 42 death was adequately explained. The three groups of SID infants were concordant with regard to the following parameters: the peak of mortality was found at about three months of age; among the SID probands, first born were less, third and later born were more numerous than in the general population; mothers of first, second and third born SID probands were younger as compared to the general population; SID probands were born twice as often in October as in March. Differences between children of Swiss or foreign parentage respectively were of minor significance with relatively few illegitimate and relatively many foster children among the foreign SID probands. 185 diseased children who had died in hospital and on whom autopsies were performed served as one control group; a second control group consisted of 1020 unselected newborns of the city of Zurich. The test groups resembled one another in their deviation from the controls and thus seem to form an entity distinct from non-SID infants.

Achondrogenesis type I: light and electron-microscopic studies.

The light- and electron-microscopic structure of articular and costal cartilage in a case of achondrogenesis type I has been described. The most characteristic ultrastructural change in the chondrocytes was conspicuous dilatation of the rough endoplasmatic reticulum (RER) which contained amorphous electronopaque material. This change in the RER was accompanied by marked hypertrophy of the Golgi apparatus; the matrix was basically unchanged.

Amniotic cells in fetal Fallopian tubes.

In a dizygotic 25-week-old twin fetus the histologic examination of the Fallopian tubes disclosed an unusual finding: the bilateral salpingeal lumen was filled with amniotic cells. The latter were especially numerous in the ampulla which still had few folds and which therefore had a comparatively wide lumen. Amniotic cells and numerous granulocytes were present in stomach and duodenum, but no focus of perforation could be demonstrated. The clinical significance of the so far unknown resorptive potential of the Fallopian tubes and the possible late complications of prenatal intraperitoneal blood transfusions are discussed.

Aberrant subclavian artery (arteria lusoria): sex differences in the prevalence of various forms of the malformation. Evaluation of 1378 observations.

43 original and 1335 previously published observations of aberrant subclavian artery (A. lusoria) were analyzed. The sex distribution varied for different types of the malformation: females predominated over males in instances of right aberrant subclavian artery and if pre-stenotic A. lusoria was combined with coarctation of the aorta. Male predominance was found in cases of combination of post-stenotic A. lusoria with coarctation and of aberrant left subclavian artery. An equal sex distribution was observed for A. lusoria combined with interruption of the aortic arch. Clinical, pathological and embryological aspects of the condition are discussed.

[Aberrant subclavian arteries: predominance in females (author's transl)]. / Abnormer Abgang der Arteriae subclaviae: Häufigeres Vorkommen beim weiblichen Geschlecht

Thirty-five cases of aberrant subclavian artery were observed in 1408 consecutive necropsies on fetuses, newborns, infants and children; the autopsies were performed by the same pathologist. The right subclavian artery was found to be involved in 32 cases, the left subclavian artery in 3 cases. The artery always passed behind the esophagus. In 12 of the cases, the aberrant subclavian artery occurred as an isolated anomaly. In the remainder of the cases the aberrant subclavian artery was associated with malformations of the heart and the great vessels; coexistent extracardial defects were also noted. Of the 35 cases 13 were males and 22 females. In reviewing the literature a series of 431 cases is presented. Of these cases the aberrant subclavian artery occurred in 177 males and 254 females. The predominance in females is statistically established.