Janet Vaughan

Clinical and echographic features of in utero cardiac dysfunction in the recipient twin in twin-twin transfusion syndrome.

OBJECTIVE--Fetal twin-twin transfusion syndrome (TTTS) presenting in the second trimester has been associated with almost no perinatal survival until recently, when serial drainage of amniotic fluid has improved the prognosis to 70%-80%. Most recipient twins now survive but develop cardiac dysfunction. The study was undertaken to evaluate the abnormal echocardiographic features and clinical complications of cardiac disease in the recipient twin of TTTS. DESIGN--Antenatal and postnatal echocardiographic and clinical observational study. SETTING--Antenatal studies in a tertiary referral centre. Postnatal management and follow up were performed by the same paediatric cardiologist, either at the obstetric hospital or at the regional referral centre. PATIENTS--Twin pregnancies complicated by TTTS with severe polyhydramnios diagnosed earlier than 25 weeks that proceeded until viability (n = 5). INTERVENTION--Serial fetal echocardiography with colour Doppler. Postnatal echocardiography in the first week and between two and seven months. Serial amnioreduction was performed in all pregnancies. Digoxin treatment, pericardiocentesis, paracentesis, or laser ablation of placental anastomoses was undertaken when there was hydrops. RESULTS--Increased cardiothoracic ratio and tricuspid regurgitation were seen in all recipient twins. High pulmonary artery velocities developed in three. One recipient twin died a week after delivery of endocardial fibroelastosis and infundibular pulmonary stenosis. Two other had balloon dilatation for pulmonary stenosis, one shortly after birth and one at four months. A further twin has apical thickening of the right ventricle at six months. The remaining recipient twin had normal echocardiographic findings at follow up. CONCLUSION--This report characterises for the first time a cardiac disease acquired in utero in the recipient twin in pregnancies complicated by TTTS. Clinical manifestations in utero range from mild to critical pulmonary stenosis or lethal cardiomyopathy. Although perinatal prognosis seems to be related to the severity of dysfunction when first diagnosed in utero, follow up in infancy is recommended in view of the possibility of progressive pulmonary stenosis.

Impaired Fetal Blood Gas Status in Polyhydramnios and Its Relation to Raised Amniotic Pressure

A substantial proportion of perinatal losses in polyhydramnios occur as unexplained normally formed stillbirths. In order to investigate the relationship between fetal condition and raised amniotic pressure (AP), fetal blood gas and acid-base status were determined together with AP in 22 pregnancies with polyhydramnios. At fetal blood sampling, 8 (36%) had a venous pH value and 16 (73%) a pO2 value below the reference range. Both fetal pH and pO2 were significantly negatively correlated with the degree of elevation in AP (y = 7.43 - 0.036x, r = 0.56, p = 0.006, where y = pH and x = AP z score, and y = -1.6 - 0.48x, r = 0.54, p = 0.01, where y = pO2 z score, respectively). Although some of these fetuses were hydropic, had congenital anomalies, or were from multiple pregnancies, univariate and multiple logistic regression analyses indicated that the above associations could not be accounted for by these potentially confounding variables. This work suggests that abnormal fetal blood gas status in human pregnancies with poly-hydramnios is associated with elevated AP.

Discrimination between strontium and calcium in bone and the transfer from blood to bone in the rabbit

Seven-month-old rabbits were injected intravenously with 90Sr or 45Ca and killed serially at time intervals from ten minutes to 460 days after injection. The uptake of both isotopes was about the same at ten minutes after injection. This uptake represented about one-third of the maximum uptake of 45Ca, which was observed at one day and about half of the maximum uptake of 90Sr which was observed at four hours. Although the maximum uptake of 45Ca is greater than that of 90Sr the rate of uptake and removal of 90Sr was greater than that of 45Ca. The turnover of both 90Sr and 45Ca was greater in the trabecular bone of the vertebrae and in the ends of the long bones than in the mid-cortex of the femur and tibia at short times after injection. Those portions of bone which showed the highest rates of turnover were found to be associated with relatively lower values for the stable strontium/calcium ratios. This suggested that the net effect of incorporation and release favoured the preferential retention of calciu...

Distribution, Excretion and Effects of Plutonium as a Bone-Seeker

Sixteen isotopes of plutonium are known, (Lederer et al., 1967). These are listed in Table 10.1. Only two of these are at present recognised as of biological importance. Plutonium-239 is used increasingly for industrial and military purposes and its biological effects have therefore been the subject of intense study. Plutonium-238 also has practical applications which have encouraged some analyses of its metabolic and biological effects. The shorter-lived 237Pu, it has been suggested, may have value in metabolic studies.

The relative hazards of strontium 90 and radium 226.

A study has been made of the concentrations and linear dimensions of radium deposits in the skeleton of a man exposed to the risk of radium ingestion over a long period of adult life, and having a terminal body burden of 0·48 μg of Ra. Assuming deposits of 90Sr of the same sizes and relative concentrations as in the radium case, calculations have been made of the dose to soft tissues embedded in bone. Comparison has then been made of the dose from α and β particles under the same conditions of deposition. For the sites considered, the radiation dose non-uniformity factor for 90Sr varies from 0·9 to 3·1, while that for Ra varies from 1 to 16. A critical examination has then been made of the maximum permissible burden for 90Sr, at present based on a comparison with radium, using data from certain animal experiments. It is considered that this comparison is open to serious objection. It is also shown that a comparison of the maximum permissible burdens for those two isotopes on the basis of radiation dose pr...

Amiodarone given by three routes to terminate fetal atrial flutter associated with severe hydrops

Background: We describe the concurrent administration of amiodarone using three different routes in order to provide: 1) rapid and adequate fetal loading without giving unduly high doses to the mother, and 2) a maintenance dose to the fetus without risking repeated invasive procedures.

The effect of a single injection of high dose of 90Sr (500-1000 muc./kg. in rabbits.

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Distribution of 239Pu in the bone marrow and on the endosteal surface of the femur of adult rabbits following injection of 239Pu(NO3)4

Abstract A study has been made of the distribution of 239Pu in the bone marrow and on the endosteal bone surfaces of adult rabbits following both the intramuscular and intravenous injection of 239Pu(NO3)4. Differences in the marrow distribution can probably be attributed to differences in the colloidal character of the plutonium reaching the marrow, depending on the rout of injection. Examination of the distribution of the 239Pu, as seen in the heavy band of α tracks on the endosteal surface both of the bone after removal of the marrow and on the extruded marrow, showed that approximately 40 per cent was present in or on the endosteal cells and 60 per cent was present on the mineral or matrix of the bone surface free of cells. The amount of 239Pu in the endosteal cells varied in a similar manner with time after injection to the amount of 239Pu on the mineral surface. The presence of 239Pu in the osteogenic cells themselves may account for the great carcinogenicity of this radionuclide.

Radiation Dose and its Relation to Damage in the Rabbit Tibia Following a Single Injection and Daily Feeding of 90 Sr

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The radiosensitive tissues in bone

A Task Group of the International Commission on Radiological Protection (ICRP Publication 11, 1968) reviewed the tissues at risk of malignant transformation from the deposition of radioactive material in bone. It noted specially: (1) the haemopoietic bone marrow with respect to leukaemia; (2) the osteoprogenitive tissues of endosteum with respect to osteosarcoma; and (3) certain epithelia in cranial air sinuses, outside bone itself but closely adherent to it, and subject to carcinoma.