Data-driven Modeling of Hemodynamics and its Role on Thrombus Size and Shape in Aortic Dissections

Aortic dissection is a pathology that manifests due to microstructural defects in the aortic wall. Blood enters the damaged wall through an intimal tear, thereby creating a so-called false lumen and exposing the blood to thrombogenic intramural constituents such as collagen. The natural history of this acute vascular injury thus depends, in part, on thrombus formation, maturation, and possible healing within the false lumen. A key question is: Why do some false lumens thrombose completely while others thrombose partially or little at all? An ability to predict the location and extent of thrombus in subjects with dissection could contribute significantly to clinical decision-making, including interventional design. We develop, for the first time, a data-driven particle-continuum model for thrombus formation in a murine model of aortic dissection. In the proposed model, we simulate a final-value problem in lieu of the original initial-value problem with significantly fewer particles that may grow in size upon activation, thus representing the local concentration of blood-borne species. Numerical results confirm that geometry and local hemodynamics play significant roles in the acute progression of thrombus. Despite geometrical differences between murine and human dissections, mouse models can provide considerable insight and have gained popularity owing to their reproducibility. Our results for three classes of geometrically different false lumens show that thrombus forms and extends to a greater extent in regions with lower bulk shear rates. Dense thrombi are less likely to form in high-shear zones and in the presence of strong vortices. The present data-driven study suggests that the proposed model is robust and can be employed to assess thrombus formation in human aortic dissections.

A multicentre pilot study of sulphasalazine in juvenile chronic arthritis

In this multicentre pilot study of sulphasalazine in juvenile chronic arthritis, the mode of onset and course of the disease, and when available, the HLA status, was recorded on the entry form. After appropriate clinical and laboratory appraisal, sulphasalazine up to 40 mg/kg/day was given for one year with assessments at 0, 1, 3, 6, 9 and 12 months. Fifty-one patients enrolled, 8 of whom were withdrawn because of side effects. In the remainder by 12 months a good effect was noted in 12, 8 having pauci-articular onset disease commencing after the age of 9 years, of whom 6 carried HLA B27. It was relatively ineffective in the other subgroups. The frequency and severity of side effects was similar to that seen in adults. Further evaluation in controlled trials is required in older onset pauci-articular arthritis, taking due note of the patient's HLA status, and also in juvenile psoriatic arthritis and seropositive juvenile rheumatoid arthritis.

A recognisable short stature syndrome with premature aging and pigmented naevi

We report the progress up to the age of seven years of a small for dates baby whose face and neck are strikingly devoid of subcutaneous tissue and who has, in addition, multiple pigmented naevi.

Maternal blood glucose control and outcome of diabetic pregnancy

The results of management of 128 consecutive pregnancies occuring in diabetic patients who received insulin from before conception and throughout pregnancy are described. Mean maternal blood glucose levels were at least 1 mmol/litre greater than levels reported in normal pregnancy. Thirty-nine percent of the neonates had significant morbidity; respiratory distress syndrome (7·7%), hypocalcaemia (4·6%) and polycythaemia (10%) could be related to higher maternal blood glucose levels. Neonatal hypoglycaemia (9·2%), hyperbilirubinaemia (13·8%) and birth weight corrected for gestational age were not directly related to maternal blood glucose. This degree of maternal blood glucose control has reduced the large for dates infants (greater than 90th centile for gestational age) to 7%. Further reduction in the morbidity of infants of diabetic mothers requires studies of physiological maternal blood glucose levels which may not be possible with conventional insulin treatment as well as further efforts to reduce prematurity.

A clinical study of a family with Cockayne's syndrome

Two sibs with Cockayne's syndrome are described. The recognised cellular sensitivity to ultraviolet light is confirmed. The clinical features in the two children are described and comparisons are made with some forms of xeroderma pigmentosum, a condition in which there is progressive neurological degeneration and cellular sensitivity to ultraviolet irradiation.

Prenatal diagnosis of disease

We are still in the early days as far as antenatal diagnosis of fetal disease and abnormality are concerned. All of the techniques show a high degree of accuracy if used in the correct circumstances but, apart from the use of maternal blood to assess the Rhesus status and screen for neural tube defects and amniocentesis to search for age-dependent mongolism, present techniques are too cumbersome, inaccurate and dangerous to be offered as routine antenatal tests. The rapid development in ultrasound equipment and expertise and the recent advances in fetal blood sampling and biochemistry suggest that there will be continued and rapid expansion within the field.

Segregation of ABO, AK1 and ACONs in families with abnormalities of chromosome 9

Some families with abnormalities of chromosome 9 have been combined with others from the literature to show that AK1 and ABO must lie near the end of that chromosome. Current evidence suggests that both lie in band 9q34. MNSs, GPT and Gc can be excluded from chromosome 9.

Maternal diabetes mellitus and congenital malformation. Survey of 205 cases

Twenty-five out of 205 (i.e. 12%) babies born to diabetic mothers in the Birmingham Maternity Hospital in the period 1969-1974 were malformed as against 6% in a control group. The incidence was highest in the group where mothers were on insulin at the time of conception (17 out of 117, i.e. 15%). No correlation was observed between major malformation in this group and age of onset or duration of the diabetes, progressive vascular complications, maternal age, or parity. Cardiovascular malformations were over-represented.

A form of metatropic dwarfism in two brothers

Two brothers are described with identical features of short-limbed dwarfism, normal face, hands and feet, respiratory difficulties and mild scoliosis. It proved impossible to offer a definitive diagnosis, though radiological features as a whole bore similarities to those of metatropic dwarfism, with the most notable feature the narrowing of the ossified components of the vertebral bodies.

Cystic fibrosis in 3 Pakistani children

Images

Arrhinencephaly associated with a deficiency involving chromosome 18

Images

Syndrome associated with a deficiency of part of the long arm of chromosome no. 18

Images