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Biomedical subjects

B Sarby

Publications and source records attributed to B Sarby.

At least 19 recordsLinked to original sources
PubMed1997

Tissue distribution of transplanted fetal liver cells in the human fetal recipient.

OBJECTIVE: Our purpose was to study the tissue distribution and concentrations of transplanted fetal liver cells in the human fetus. STUDY DESIGN: Radiolabeled indium 111 fetal liver cells were injected in vivo under ultrasonographic guidance into 10 normal fetuses (13 to 17 weeks of gestation) before a prostaglandin abortion. Six fetuses were injected intraperitoneally and four intracardially. Another two fetuses serving as controls were injected with indium-labeled maternal plasma. The fetuses were all alive, at least until 6 hours before expulsion. After expulsion the fetuses were dissected, and radioactivity was measured in various fetal tissues. Results for each tissue were expressed as percentages of the total injected dose. RESULTS: Significantly greater uptake of fetal liver cells in the liver, spleen, thymus, kidney, lung, and placenta was obtained with intracardiac than with intraperitoneal injection. Skeletal uptake did not differ in relation to mode of administration. With intracardiac injection uptake was greater in such parenchymal organs as the liver, spleen, and thymus (4.9%, 4.0%, and 3.9%, respectively). Uptake in the rib, clavicle, humerus, and sternum was 2.7%, 1.8%, 2.1%, and 1.1%, respectively. Placental uptake was 0.1%. The intracardiac route yielded a higher concentration of cells in different fetal organs than did injection of only radiolabeled maternal plasma, suggesting an active uptake of cells in different fetal hematopoietic organs. CONCLUSION: The mode of administration of fetal liver cells seems to be a major determinant of donor cell concentration in the transplanted human fetus and may be a significant determinant of the rate of successful engraftment.

Cell Movement↗
PubMed1994

Hormonal, metabolic, and circulatory responses to insulin-induced hypoglycemia in pregnant and nonpregnant women with insulin-dependent diabetes.

Strict blood glucose control of pregnant women with insulin-dependent diabetes is associated with increased risk of hypoglycemia. The hormonal and circulatory responses to an acute episode of insulin-induced hypoglycemia were studied in eight pregestational and one gestational diabetic women during the last trimester of pregnancy and 8 to 12 weeks postpartum. Following an overnight fast, insulin was injected intravenously (0.1 to 0.2 IU insulin/kg). Blood samples were taken at -15, 0, 15, 30, 40, 60, 90, and 120 minutes for analyses of metabolites (glucose, nonesterified fatty acid (NEFA), glycerol, 3-hydroxybutyrate) and counterregulatory hormones (epinephrine, norepinephrine, glucagon, and cortisol). Placental scintigraphy (indium-113m) was performed in five pregnant patients before and during hypoglycemia. Both during pregnancy and postpartum, blood glucose decreased to the same low level (3.2 mmol/L) concomitantly with significant decreases in NEFA, glycerol, and 3-hydroxybutyrate. Epinephrine and norepinephrine showed significant and similar increases on both occasions in relation to hypoglycemia, although there was no response in glucagon and cortisol concentrations. Maternal heart rate was significantly higher in the pregnant compared with the nonpregnant state and increased significantly in both groups in response to hypoglycemia. Placental blood flow showed no consistent changes and was unrelated to the glucose and catecholamine responses. Fetal heart rate remained unchanged. Thus, it seems as if hormonal and circulatory responses to acute hypoglycemia are not altered in diabetic women during pregnancy.

3-Hydroxybutyric Acid↗
PubMed1991

Isradipine, a new calcium antagonist: effects on maternal and fetal hemodynamics.

To assess the effect of isradipine on blood pressure, and uteroplacental and fetal blood flows in pregnancy-induced hypertension, 41 women with a diastolic blood pressure greater than or equal to 95 mm Hg were included in our study. Of these, 27 received isradipine 5 mg twice daily. Uteroplacental blood flow index was calculated from the activity-time curve of the very low radiation from the placenta after intravenous injection of 18.5 MBq indium-113m. Blood flow velocity was measured in the uterine and umbilical arteries, and fetal aorta, using the pulsed Doppler technique. Investigations were performed before and after 1 week of isradipine. A control group of 14 women was examined in the same way. The isradipine group showed a significant reduction in mean arterial pressure (from 117 to 112 mm Hg) whereas there was no change in the controls. Uteroplacental blood flow indices were similar before treatment in both groups and did not change during treatment. Furthermore, the pulsatility indices were the same in both groups at the first examination and also did not change. Isradipine had no adverse effects on the fetus. In conclusion, isradipine lowered blood pressure without altering uteroplacental or fetal blood flows.

Adult↗
PubMed1990

Uteroplacental blood flow measured by placental scintigraphy during epidural anaesthesia for caesarean section.

The uteroplacental blood flow was measured before and during epidural anaesthesia for caesarean section in 11 women. The blood flow was measured with dynamic placental scintigraphy. After an i.v. injection of indium-113m chloride, the gamma radiation over the placenta was recorded with a computer-linked scintillation camera. The uteroplacental blood flow could be calculated from the isotope accumulation curve. The anaesthesia was performed with bupivacaine plain 0.5%, 18-22 ml and a preload of a balanced electrolyte solution 10 ml/kg b.w. was given. The placental blood flow decreased in eight patients and increased in three with a median change of -21%, not being statistically significant. No correlation between maternal blood pressure and placental blood flow was found.

Adult↗
PubMed1990

The effect on uteroplacental blood flow of epidural anaesthesia containing adrenaline for caesarean section.

The effect on uteroplacental blood flow of an epidural anaesthesia containing adrenaline for caesarean section was investigated in ten healthy women using dynamic placental scintigraphy with indium-113m and a computer-linked gamma camera. The epidural anaesthesia was performed with 18-22 ml bupivacaine 5 mg/ml with adrenaline 2.5 micrograms/ml followed by an i.v. balanced electrolyte infusion of 10 ml/kg b.w. A significant median decrease in the total maternal placental blood flow of 34% was found (P less than 0.01). There was also a significant decrease in maternal mean blood pressure of 3 mmHg (0.4 kPa) (P less than 0.05) and a significant negative correlation between the change in maternal blood pressure and the change in uteroplacental blood flow (r = -0.69, P less than 0.05).

Adult↗
PubMed1987

Equipment for radiation surgery using narrow 185 MeV proton beams. Dosimetry and design.

The purpose of the present work was to optimize and standardize irradiation conditions and dosimetry methods in order to investigate the prerequisites for the routine use of narrow high energy proton beams for cerebral radiation surgery. Particular importance was laid on the design of the arrangements for defining and controlling the path of the beam in the laboratory in view of the desirability of working with well-defined parallel beams containing a minimal contribution of scattered and secondary radiation. At the same time it was intended that this apparatus should be used to adjust the beam reproducibly onto an ideal beam path prior to each irradiation session. It was also considered desirable to be able to supervise the centering and the structure of the beam during the irradiations in view of the variations which can arise due to varying running conditions in the synchrocyclotron. The beam was collimated and led to the place where the irradiations were to be performed, 25 metres from the synchrocyclotron, with a system of focusing quadrupole magnets and bending magnets. Final collimation of the beam penetrating the object was arranged with a system of accurately aligned cylindrical and plane-parallel metal apertures. The energy of the protons in the beam was 185 +/- 0.2 MeV and the maximum total fluence was 5 X 10(10) protons/s. A method of 11C activation dosimetry was developed with which an absolute determination of the fluence and the dose in the proton beam could be made with good accuracy. These determinations were performed by irradiating small polystyrene cylinders placed along the beam axis at the isocentre. The activity induced in the cylinders by the protons was measured in a well-type crystal detector. The efficiency of the detector for the detection of annihilation photons was determined before each measurement by means of calibration with standardized activities of 22Na and 60Co. The overall uncertainty in the dose determinations using 11C activation dosimetry was +/- 8 per cent. Monitoring of the dose during irradiation was performed with an ionization chamber. Since it was most important to minimize the scattering of the protons, this chamber was designed as a 'free air chamber' with the electrodes parallel to the beam. The chamber could not be used for absolute measurements, however, since there was a contribution to the ionization in the chamber from scattered protons and secondary radiation from the walls of the collimator defining the cross section of the ionization volume.(ABSTRACT TRUNCATED AT 400 WORDS)

Energy Transfer↗
PubMed1987

Effective dose equivalent from intraoral radiography.

By means of available data of mean organ doses from intraoral radiography the effective dose equivalent from dental radiography was calculated. The dose values used correspond to 65 kVp, 0.2 m FSD and 20 exposures with film in speed group D. The effective dose equivalent was calculated for circular (55 mm diameter) as well as rectangular collimator (35 mm X 44 mm) and amounted to 0.23 and 0.14 mSv, respectively. In comparison with the annual natural radiation the corresponding time would be 6 and 3 weeks, respectively. Following the definition of the effective dose equivalent by ICRP (1977) it was found that the most radiosensitive organs contributed 20-25 per cent of the total effective dose equivalent. The organs with the highest weighting factors thus received very small or negligible dose equivalents. The calculation necessitates a detailed knowledge of the absorbed doses and the weighting factors, which made the application for dental radiography somewhat uncertain. The concept of energy imparted might be a more direct measure to compare the risk from different examinations in dental radiography.

Energy Transfer↗
PubMed1986

Energy imparted from intraoral radiography.

During the recent decade the equipment for dental radiography in Sweden has been standardized by the Swedish National Institute for Radiation Protection. The aim of this study was to experimentally determine the energy imparted to a phantom from a full survey with 20 intraoral films as well as from a single bitewing projection, using this standardized technique. Thermoluminescence dosimeters in predetermined volume elements of an anatomically formed tissue equivalent Alderson-phantom were irradiated (65 k Vp) using both a rectangular and a circular collimator of 0.2 m FSD. Exposure times fitted to film in speed group D were used. The energy imparted was determined from the integrated absorbed doses in the volume elements as well as calculated using published depth dose data. The energy imparted was found to be 9.6 mJ (circular collimator) and 5.9 mJ (rectangular collimator) for the full survey. For the single bitewing exposure the energy imparted was 0.42 mJ (circular collimator) and 0.29 mJ (rectangular collimator). With the rectangular collimator and film in speed group D the energy imparted from a full survey will correspond approximately to two weeks of environmental irradiation. With more sensitive film in speed group E the energy imparted would further be reduced by 40 per cent with retained diagnostic information.

Head↗
PubMed1984

Uteroplacental blood flow in pregnancy hypertension after the administration of a beta-adrenoceptor blocker, pindolol.

The effect of a beta-adrenoceptor blocker, pindolol, on uteroplacental blood flow was determined in 10 women with pregnancy hypertension using an isotope technique giving a very low radiation dose. 0.5 mCi 113mIn was injected intravenously before and 30 min after 10 mg pindolol was given orally. After the administrations of 113mIn serial scintigrams were recorded for 240 s by a gamma camera on line with a computer, and the placenta was outlined for time-activity analysis of the isotope accumulation curves. From these curves a relative measure of the uteroplacental blood flow could be determined. Pindolol induced a significant fall in mean arterial pressure but there was no reduction of uteroplacental blood flow index.

Cyclic AMP↗
PubMed1984

Labetalol for the treatment of hypertension in pregnancy. Pharmacokinetics and effects on the uteroplacental blood flow.

Plasma levels of labetalol were measured in 7 hypertensive pregnant women who were given 200 mg three times daily orally. The plasma concentrations were usually lower than those reported in the non-pregnant state at a comparative dose. In 5 women the ratio between fetal and maternal plasma labetalol concentrations could be calculated at parturition. The median value of this quotient was about 50%. The effect of labetalol 1 mg/kg body weight intravenously was registered with functional placental scintigraphy. Fifteen women participated. A computer-linked gamma camera above the uterus registered the radioactivity in the placental region after two intravenous bolus injections of 18.5 MBq indium-113m chloride. From the radioactivity uptake curves, uteroplacental blood flow indices could be calculated before and 30 minutes after the labetalol injection. Despite a significant reduction in maternal blood pressure, no change in uteroplacental blood flow index was found. This could indicate that the vascular resistance in the maternal placental circulation was reduced by labetalol.

Ethanolamines↗
PubMed1983

Uteroplacental blood flow index in intrauterine growth retardation of fetal or maternal origin.

Uteroplacental blood flow index was determined in 30 women with intrauterine growth retardation (IUGR group) and in 26 women without fetal growth retardation (control group) during the last trimester of pregnancy. After 1 mCi (37 MBq) of indium-113m chloride had been injected intravenously the radiation was registered by a computer-linked scintillation camera positioned above the placenta during 10 s-intervals for 240 s. From the isotope accumulation curve a uteroplacental blood flow index could be calculated for each patient. The median blood flow index in the IUGR group was less than half of that in the control group. In the IUGR group the index was as low in the six women who gave birth to infants with congenital malformations as in the other 24 women in whom fetal growth retardation was due to maternal factors.

Adolescent↗
PubMed1983

Acute effect of dihydralazine on uteroplacental blood flow in hypertension during pregnancy.

The uteroplacental blood flow was measured in 12 women with hypertension during pregnancy before and after intravenous injection of dihydralazine. After intravenous administration of 18.5 MBq (0.5 mCi) 113mIn, the gamma radiation emanating from the placenta was recorded with a computer-linked gamma camera during 10-second intervals for 240 s. From time-activity analysis of the isotope curve a uteroplacental blood flow index could be calculated. 30 min after the intravenous injection of dihydralazine, 18.5 MBq 113mIn were again administered, and a second uteroplacental blood flow index was calculated. After dihydralazine administration there was a significant reduction of mean blood pressure (p less than 0.01) and an increase of mean maternal heart rate (p less than 0.01). There was no significant change in uteroplacental blood flow or in uteroplacental vascular resistance.

Blood Pressure↗
PubMed1983

Functional placental scintigraphy. A methodologic and clinical investigation.

A method to determine the uteroplacental blood flow in the last trimester of pregnancy is presented. After intravenous injection of 37 MBq 113Inm the radiation above the placenta was recorded in 10 s intervals for 240 s by a scintillation camera. The data are presented in a time-activity curve, in which the maximum activity is proportional to the placenta volume, rise time can be defined and the quotient maximum activity/rise time is calculated. This quotient is an index of the uteroplacental blood flow which can be used for comparison of a series of patients.

Female↗
PubMed1982

Uteroplacental blood flow in diabetic pregnancy: measurements with indium 113m and a computer-linked gamma camera.

The uteroplacental blood flow index in the last trimester of pregnancy in 26 women with diabetes mellitus was compared to that in 41 healthy control subjects. After an intravenous injection of 1 mCi of indium 113m, the radiation over the placenta was recorded with a computer-linked gamma camera. From time-activity analysis of the isotope accumulation curve, a uteroplacental blood flow index could be calculated. In the diabetic pregnant women, the maternal-placental blood flow index was reduced 35% to 45% compared to that in healthy women. The blood flow index tended to be further impaired in those diabetic women who had higher blood glucose values.

Adolescent↗
PubMed1982

Labetalol, a combined alpha- and beta-blocker, in hypertension of pregnancy.

Labetalol was given to women with hypertension of pregnancy in their last trimester to study its acute effect on circulation and metabolism. Seven women were given 50 mg labetalol i v. There was a significant decrease of blood pressure from a mean of 143/101 +/- 4/2 (SEM) to 127/88 +/- 5/2 mm Hg. Maternal heart rate fell significantly from 77 +/- 5 to 68 +/- 3 beats per min. These changes persisted during a three-hour observation period. The hypotensive response was accompanied by a significant increase in plasma noradrenaline from 1.54 +/- 0.16 to 2.37 +/- 0.41 nmol/l, suggesting sympathetic activation. Plasma cyclic AMP, which is increased by beta 2-adrenoceptor stimulation, was significantly elevated after labetalol. This supports the hypothesis of partial beta-agonist activity of labetalol. Lipid metabolism, as judged from measurements of plasma FFA, glycerol and 3-hydroxybuturic acid, showed little change. The acute effect of labetalol on uteroplacental blood flow was determined in eight women with pregnancy hypertension using a gammacamera on line with a computer. 0.5 mCi indium-113m was given i v before and 30 min after labetalol was administered i v in a dose of 1 mg per kg body weight. After the injections of indium-113m, serial scintigrams were recorded during 10 s periods for 240 s. By computerized summation of the scintigrams, an image was obtained in which the placenta could be outlined for time-activity analysis of the isotope accumulation curve. From this curve a uteroplacental blood flow index could be calculated. Labetalol induced a significant drop of mean arterial blood pressure from 114 +/- mm Hg to 100 +/- 3 mm Hg after 30 min in this group of women. However, the uteroplacental blood flow index did not change. As we have earlier shown with this technique that uteroplacental blood flow can be severely impaired in hypertension of pregnancy, the finding of substained uteroplacental blood flow simultaneously with a decrease in blood pressure should be of clinical importance. Taken together with other studies of clinical effects, these results indicate that labetalol is useful in the treatment of hypertension of pregnancy.

Adult↗