Summary:Quadricuspid aortic valves (QAV) are a rare but well recognized cause of significant aortic regurgitation. The first case was found reported in 1862. Since then there have been 110 reported cases of QAV and we report 4 more. Previously, these were diagnosed at the time of surgery or postmortem examination. With advances in echocardiography, including harmonic imaging, and also the advent of transesophageal echocardiography, more cases are being diagnosed prior to surgery. We describe four more cases, three diagnosed preoperatively and one at the time of surgery, and then review the previously reported cases. Of the 114 cases reported, 46 had the aortic valve replaced, most commonly in the 5th and 6th decade of life. Hurwitz and Roberts classified quadricuspid valves according to the size of the leaflets. It has previously been believed that QAVs with four equal sized leaflets were less likely to develop significant aortic regurgitation; however, on review of the available cases, this would not appear to be the case. The preoperative diagnosis of QAVs is important as they can be associated with abnormally placed coronary ostium. Of the 114 cases reported, there are 10 reports of abnormally placed ostia. There has been at least one reported case of death occurring because of obstruction of an abnormally placed right coronary ostium by a prosthetic aortic valve.

Glucose, glucagon, tolbutamide and L-leucine stimulated insulin secretion from rabbit pancreas studied in vitro. In each case stimulation was inhibited by omitting calcium from the incubation medium. The omission of magnesium had no effect on glucose stimulated insulin secretion but 10 mM magnesium inhibited secretion. Optimal secretion of insulin occurred at an extracellular calcium concentration of 2.64 mM. The omission of calcium inhibited glucose-stimulated insulin secretion from pancreas of 27 day rabbit foetuses.

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. (1972). Archives of Disease in Childhood, 47, 652. Cellular development of some human organs before birth. The total amount of DNA and the protein/DNA ratio have been measured in the kidneys, heart, liver, and gastrocnemius muscles of 56 human fetuses and newborn infants of 13-42 weeks' gestational age. The total amount of DNA in each organ approximately doubled every week up to the 25th; thereafter the rate of increase was slower. The protein/DNA ratio in each organ increased rapidly in the last 10 weeks of intrauterine life. Before 30 weeks there was some increase in the protein/DNA ratio in the kidneys, heart, and gastrocnemius muscles, but no significant change in the liver. In 5 small-for-dates infants the protein/DNA ratio was normal, whereas the total DNA tended to be low.The cellular growth of the brain of the human fetus (Winick, 1968;Dobbing and Sands, 1970;Dobbing, 1970), and of the placenta (Winick, Coscia, and Noble, 1967), have been investigated systematically by chemical means, but other organs have been neglected. This paper reports observations on the growth of the human kidneys, heart, liver, and gastrocnemius muscles before birth. Total DNA was used as an index of the number of cells in the internal organs and the protein/DNA ratio as an index of the mean cell size. The quantity of DNA was taken to indicate the number of nuclei in the gastrocnemii, and the protein/DNA ratio the relation between cytoplasm and nucleus. Materials and MethodsOrgans from 28 fetuses delivered by hysterotomy for the therapeutic termination of pregnancy, and from 28 fresh stillborn and livebom infants who died within the first week of life were collected. All the fetuses were normal on clinical judgment. Infants with major congenital abnormalities or rhesus incompatability were excluded. Five of the liveborn infants were small for their gestational age, and this was presumably due to nutritional deprivation before birth. Specimens were also collected from 5 adults, 2 men and 3 women, aged 39 to 75 years, for comparison.The kidneys, heart, liver, and gastrocnemii were collected within one hour of death from the fetuses, weighed to the nearest mg, wrapped in plastic film ('Snapwrap'), frozen in liquid nitrogen, and stored at -20°C until analysed. The same organs were collected from the liveborn infants and adults at necropsy (which was usually performed within 24 hours of death), weighed, and portions were then treated similarly.The frozen organs were reweighed and were then thawed sufficiently to be homogenized, but the gastrocnemii were ground to a powder in liquid nitrogen. Portions of all the thawed, homogenized tissues were taken for determination of protein and DNA. Protein was precipitated from one sample with 10%/ trichloroacetic acid, and nitrogen was determined on the precipitate by the micro-Kjeldahl method (Chibnall, Rees, and Williams, 1943 Fig. 1-4 show the total DNA and the protein/ DNA ratios (mg protein/mg DNA) in the gastrocnemii, kidneys, heart, and liver plotted against gestational age. A semilogar...