A BrdU-requiring fragile site on chromosome 12

A BrdU-requiring fragile site, fra(12)(q24.2), on human chromosome 12 of some individuals is reported. This fragile site is inherited in a Mendelian codominant fashion and does not seem to be associated with any physical or mental abnormality in carriers. It was mostly observed as a chromatid gap: no acentric fragments, triradials or deleted chromosomes were found. The fra(12)(q24.2) was expressed in 34%-48% of metaphases in lymphocyte cultures from carriers when BrdU and FdU were added 6.5 h before harvest, while the expression ranged between 5% and 20% when the cultures were treated with BrdU alone. The fra(12)(q24.2) represents the second BrdU-requiring rare fragile site described on human chromosomes.

Late manifestation of autosomal-recessive polycystic kidney disease in two sisters

We report on 2 siblings with autosomal-recessive polycystic kidney disease, diagnosed at the ages of 14 and 18 years, respectively. Clinical findings and differential diagnosis, especially for autosomal-dominant polycystic kidney disease, are given. The consequences for genetic counselling are discussed.

[SPECT studies with 99mTc-HMPAO in Huntington's chorea patients]

Huntington's chorea is an autosomal dominant inherited disease with a chronic course and atrophy of the corpus striatum. PET examination shows reduced glucose metabolism in the caudate nucleus. We examined seven patients with Huntington's chorea by SPECT, using 99mTc-HMPAO. All patients had cortical defects of varying severity. In addition, five patients showed increased uptake in the region of the caudate nucleus. The specific tracer uptake due to the metabolic processes in the region of the caudate nucleus in Huntington's chorea is discussed.

[Dipyridamole and low-dose aspirin in patients with aortocoronary bypass--comparison with anticoagulation]

The effects of antiplatelet therapy (AP; dipyridamole 400 mg [beginning 2 days preoperatively] + aspirin 50 mg/day) and anticoagulation (AC) were compared prospectively in 251 patients with coronary artery bypass grafting (CABG). Two weeks postoperatively, 85.2% of AP and 81% of AC patients had all grafts patent with graft patency rates of 93.6% and 91.3% respectively (p = n.s.) Significant differences in favour of AP therapy were found in subgroups with multiple grafts and with low intraoperative graft flow. Up to 3 months postoperatively, severe complications occurred in 22 AC patients (11 bleedings) but only in 9 patients on AP therapy (p less than 0.01). Overall, AP therapy should therefore be preferred to AC in patients with CABG surgery.

Comparison of the effects of inserted C40- and C50-terminally dihydroxylated carotenoids on the mechanical properties of various phospholipid vesicles

We have measured the extent of incorporation of zeaxanthin (C40) and decaprenozeaxanthin (C50) in unilamellar vesicles of dimyristoylphosphatidylcholine (n-C14) and dipalmitoylphosphatidylcholine (n-C16). The incorporation is larger when the molecular length of the carotenoid corresponds to the thickness of the phospholipid bilayer. Stereochemically pure 2,3-di-O-phytanyl-sn-glycero-1-phosphocholine was prepared by modification of the polar heads of the phospholipids of Halobacterium halobium. Vesicles of this branched-chain ether phospholipid incorporate poorly the carotenoids, whereas egg lecithin vesicles incorporate them better. Osmotic swelling and water permeability of vesicles, with or without carotenoids, were measured in a stopped-flow, light-scattering system. The reinforcing effect (lower permeability and higher rigidity) of carotenoids at 1.5 mol% incorporation into diphytanylphosphatidylcholine vesicles is comparable to that of 5 mol% cholesterol; however, carotenoids have no measurable effect on the egg lecithin vesicles. These results imply that the reinforcement of the membrane depends on a subtle adjustment of the phospholipid-carotenoid system.

Close linkage of the Wieacker-Wolff syndrome to the DNA segment DXYS1 in proximal Xq

Linkage studies with RFLPs were performed in a large family in which the Wieacker-Wolff syndrome is segregating. In this new syndrome (McKusick, 1986, No. 31458) patients have congenital contractures, progressive neuropathic muscle atrophy, involving also some cranial nerves with oculomotor apraxia and dyspraxia of the face and tongue muscles, and mental retardation. This is an X-linked recessive syndrome. We found close linkage between the syndrome locus and the DNA segment DXYS1 (z = 3.225 at theta = 0.0) in proximal Xq.

[Psychosocial aspects of the treatment of phenylketonuria]

The psychosocial aspects of phenylketonuria (PKU) were investigated retrospectively in the families of 25 children and adolescents with classical PKU. With the help of a semistructurated questionnaire the parents were asked in interviews what impact the birth, the diagnosis of PKU in their child and the treatment itself had on them. 19 of the children had been detected by newborn screening and given early treatment. With one exception they all showed adequate intellectual development. Six other children were diagnosed late and only three of them had been given dietary treatment with some degree of success. Many of the parents reacted with shock and disbelief after being informed that their child was abnormal. In many ways the parents expressed retrospectively the wish that they had been better informed about their childs disease and had more intensive support from the medical professionals. They believed that with these prerequisites they would have been more competent in the case of their children. The data demonstrate the necessity of psychological care for the entire family of the chronically sick child.

[Cerebro-costo-mandibular syndrome without cerebral involvement in a 4-year-old boy]

In a four year old boy the combination of Robin sequence and multiple dorsal rib defects on the first day of life could be classified as cerebro-costo-mandibular syndrome. In contrast to an unfavorable clinical course with cerebral involvement which has repeatedly been observed, in our patient psychomotor development has been normal so far. A brief literature review of a total of 36 patients shows that despite a unfavorable prognosis quoad vitam, roughly half the patients have survived. Half of the surviving patients showed functional disorders of the central nervous system, and only one third was mentally retarded. The favorable clinical course documented here thus supports the hypothesis that cerebral symptoms are not an obligatory component of the syndrome, but are only to be regarded as a facultative risk in the "costo-mandibular" syndrome. Accordingly, therapeutic nihilism does not seem to be justified. The etiology of the cerebro-costo-mandibular syndrome could not be clarified unequivocally up to now. A series of family observations indicate a monogenic cause, but genetic heterogeneity can not be ruled out.

Generation in vitro of alloreactive lymphocytes is suppressed by the addition of spleen cells from mice infected with lymphocytic choriomeningitis virus

The generation of cytotoxic T cells to alloantigens in mixed lymphocyte culture was suppressed by the addition of spleen cells from adult mice acutely infected with lymphocytic choriomeningitis virus. T cells of surface phenotype Lyt 1+2+ were required for the suppression. Suppressive cells appeared also in lymph nodes, but not in the thymus. In the spleen their number was maximal 6 to 8 days after infection. Infectious virus could not be detected in the suppressive spleen cells. Therefore the virus itself does not seem to cause the effect.

Gas exchange during mechanical ventilation and spontaneous breathing. Intermittent mandatory ventilation after open heart surgery

Pulmonary gas exchange rates in eight patients after open heart surgery were studied during weaning from the ventilator. We investigated continuous positive pressure ventilation (CPPV), intermittent mandatory ventilation (IMV) and spontaneous breathing with continuous positive airway pressure (CPAP). During each mode of ventilation we measured: CO2 production (VCO2), O2 consumption (VO2), cardiac output (CO), PaO2, Qs/QT and functional residual capacity (FRC). In addition, we analyzed in each single breath: tidal volume (VT), series dead space volume (Vds), alveolar ventilation, alveolar efficiency for CO2 elimination (alv eff CO2) and end-tidal CO2 concentration (FCO2et). We compared the results of CPPV, IMV and CPAP and the mandatory breaths (MB) with the spontaneous breaths (SB) measured during IMV. CO was low during CPPV, when the patient still deeply sedated; it was increased in IMV and remained constant in the following CPAP period. VCO2 and VO2 did not differ significantly when switching from IMV to CPAP; therefore, work due to breathing seemed not to be reduced by the mandatory breath during IMV. Oxygenation (PaO2, Qs/QT) did not change significantly when switching from one mode to the other. FRC was constant when changing from CPPV to IMV, did not alter within the IMV-cycle and was reduced significantly when switching from IMV to CPAP. Dead space ventilation was reduced in SB (compared to MB). The latter result is discussed on the basis of two mechanisms: Vds was reduced and alv eff CO2 was increased. We conclude that compared to CPPV, IMV decreases mean alveolar pressure and reduces dead space ventilation at constant FRC and with constant oxygenation. This may explain why, in the weaning process, IMV makes it possible to start spontaneous breathing very early.

Familial pericentric inversion of chromosome 12

A pericentric inversion in one of the chromosomes 12, found in two families living in the same region, is described. This inversion was detected during routine chromosomal analysis in two separate laboratories. The breakpoints were at 12p112 and 12q13. The inverted segment represented approximately 20% of the length of chromosome 12. Twenty nine descendants of carriers of the inversion were investigated, and the inversion was present in 23 of them. The other six descendants showed a normal karyotype. After correction for sample bias with the single selection scheme, a segregation ratio of 3:1 was estimated, indicating that the inverted chromosome 12 was preferentially transmitted. All the carriers of the inversion were phenotypically normal, without noticeable fertility disturbances.

Reliable detection of inspiration and expiration by computer

A new computer assisted method is proposed to distinguish between the inspiratory and expiratory phases of breathing. The method is based on the analysis of both gas flow and CO2-concentration. The algorithm is effective and reliable and is most suitable in critical care patients when an uninterrupted sequence of breaths is to be analysed immediately at the bedside. Marked variations in tidal volume such as are seen in intermittent mandatory ventilation or spontaneous breathing during the phase of weaning from the ventilator, artefacts such as mechanical vibrations of the flow transducer or its connecting tubes do not disturb the analysis.

[Relation between intraoperative blood flow measurements and graft patency afer aortocoronary bypass surgery]

During aorto-coronary bypass surgery, electromagnetic flow measurements of venous grafts were performed in 50 consecutive patients at rest and after stimulation with papaverine (2 mg) to assess whether early postoperative patency was predictable. The overall patency rate at day 9-11 was 95.4% (145/152 distal grafts; 118 proximal grafts). Flow in all bypass grafts averaged 52.5 +/- 31.4 ml/min and increased after papaverine stimulation by 46.9 +/- 32.2 ml/min (p less than 0.01). 5 of 6 grafts with a flow of less than 30 ml/min and without adequate flow increase after papaverine (less than 80%) were occluded. Grafts with a flow of greater than or equal to 30 ml/min or an increase of greater than or equal to 80% after papaverine, had a high short-time patency rate (98%). Thus, perioperative flow measurements combined with papaverine stimulation predicted early patency of single grafts with an accuracy of 95%.

Accurate measurement of N2 volumes during N2 washout requires dynamic adjustment of delay time

Measurement of respiratory gas composition by a mass spectrometer lags behind the measurement of gas flow. To obtain specific gas volumes (e.g., the N2 volume) by multiplication and integration of concentration and flow, one has to synchronize flow and concentration signals using the delay time (TD) of the gas analyzer. During the N2 washout, however, gas composition changes and causes alterations of TD. This leads to errors of up to 17 and 70% in the measurement of pulmonary volume and series dead space, respectively, in an ideally mixing physical model of the lung. On the basis of Poiseuille's law and exact measurements of the characteristics of the capillary it is possible to adjust the synchronization, which improves the absolute accuracy considerably.

[Parental guilt experience in diseases of their children]

Parents of sick or handicapped children often exhibit strong guilt feelings. These can be justified but equally can be irrational, based on magic, prescientific thinking. However, quite often they have an emotionally stabilising function for the parents. Using clinical examples possible reasons for, and the importance of these parental guilt feelings in coping with the disease are analysed. Suggestions for dealing with these guilt feelings in a differentiated manner are formulated.

A simple method for estimating compliance

In intensive care medicine, pulmonary compliance is one of the very helpful diagnostic indices. Because of technical difficulties, however, the measurement of pulmonary compliance is often reduced to a rough guess of the compliance of the total respiratory system. The technical problems can be overcome using a computer to solve the basic equations with the least-squares fit (LSF) method. Unfortunately, this method requires such a long calculation time that bedside breath-by-breath calculations are impracticable on small computers. A simple computer algorithm (mean-values method) was therefore developed and compared to the LSF method. Compliance values calculated by either procedure were practically identical in ventilated patients. However, by reducing computing time to 30% of the LSF method, our mean-values algorithm enabled real-time estimation of compliance breath-by-breath.

A new X-linked syndrome with muscle atrophy, congenital contractures, and oculomotor apraxia

Six men from three generations of one family had manifestations of a possible new syndrome. All had congenital contractures of the feet at birth, a slowly progressive predominantly distal muscle atrophy, dyspraxia of the eye, face, and tongue muscles, and mild mental retardation. The pedigree is compatible with X-linked recessive inheritance with no detectable manifestations in the obligate carriers. Linkage analysis excludes close linkage with the Xg locus and a polymorphic DNA sequence from the long arm of the X chromosome (DXS17).