Fate of the DNA in plasmid-containing Escherichia coli minicells ingested by human neutrophils

Escherichia coli minicells containing the plasmid pSC101 (approximately 10 kb) or pBR322 (approximately 4 kb) were opsonized and incubated with human neutrophils. The neutrophils responded to the minicells as they would to native E coli: they ingested the minicells, discharged their granule contents into the minicell-containing phagosomes, and expressed a respiratory burst. After one hour of incubation, the fate of the ingested plasmid DNA was examined. No DNA degradation was detected by trichloroacetic acid precipitation or agarose gel electrophoresis. Moreover, when pBR322 recovered from ingested minicells was transformed into E coli, no mutations in either of the antibiotic resistance genes carried by the plasmid were detected out of many thousand transformants screened. These findings confirm the surprisingly limited effect of neutrophils on ingested DNA.

Effect of restriction of placental growth on oxygen delivery to and consumption by the pregnant uterus and fetus

Endometrial caruncles were excised from 13 sheep (caruncle sheep) before pregnancy to restrict placental growth. In subsequent pregnancies, half the caruncle fetuses were growth retarded or small (weight more than 2 SD below mean weight for control fetuses) with the remainder, normal-sized (weight within 2 SD of mean weight for control fetuses). The caruncle and 16 control sheep, each with indwelling vascular catheters, were studied between 121 and 130 days of pregnancy. Oxygen delivery to and consumption by the pregnant uterus in caruncle sheep with small fetuses was significantly reduced compared to controls while oxygen extraction was significantly increased. Oxygen tension (P02) and content in the common umbilical vein and in the descending aorta were significantly lower in small caruncle fetuses compared to controls but only P02 was lower in normal-sized caruncle fetuses. Oxygen delivery to, and consumption by, the fetus was significantly reduced in normal-sized and in small caruncle sheep compared to controls while oxygen extraction was increased in small caruncle sheep. Utero-placental oxygen consumption was significantly lower in caruncle sheep with small fetuses compared to that in controls. Despite these changes, oxygen consumption by the gravid uterus and fetus, per kg of tissue mass, was similar in both groups of caruncle and in control sheep. Utero-placental oxygen consumption per kg of utero-placental mass in caruncle sheep with small fetuses was not significantly different to that in sheep with normal-sized caruncle or control fetuses, although it averaged only 25% of that in controls. It is concluded that intrauterine growth retardation following restriction of placental growth is associated with a reduced supply of oxygen to both the pregnant uterus and fetus and a redistribution of oxygen to the fetus. This is due to the disproportionate maintenance of fetal growth relative to that of the placenta, since oxygen consumption by either, in terms of tissue mass, was not altered. Further, the greater uterine and fetal extraction of oxygen suggests that a smaller margin of safety may exist between supply and demand in intrauterine growth retardation.

Prognostic significance of electrocardiographic site of infarction after correction for enzymatic size of infarction

To assess whether the site of myocardial infarction is an independent prognostic indicator, the outcome of patients with anterior myocardial infarction was compared with that of patients with inferior infarction. A consecutive series of patients who had suffered their first myocardial infarction was analyzed (398 with anterior and 391 with inferior infarction). Patients with anterior myocardial infarction had a higher 1 year mortality than those with inferior infarction (18.3% vs 10.5%, p = .002). When patients were matched for infarct size determined by peak creatine kinase (CK) level expressed as a multiple of the upper limit of normal, those with anterior myocardial infarction tended to have a higher 1 year mortality than those with inferior infarction for all subgroups of peak CK. Early mortality (day 1 to 28 after myocardial infarction) was greater in the anterior than in the inferior myocardial infarction group (10% vs 6.4%, p = .03); this was most significant when peak CK was greater than four times normal (12.4% vs 7.0%, p = .04). Late mortality was also higher in the anterior (8.4% vs 4.1%, p = .04) than the inferior infarction group and this was most significant when peak CK was less than two times normal (15.2% vs 0%, p = .02) or greater than eight times normal (10.6% vs 4.1%, p = .04). Multivariate analysis with proportional-hazards regression confirmed the prognostic significance of location of infarction independent of peak CK level. Thus, infarct location was found to be a predictor of prognosis that is independent of infarct size based on peak CK levels.

Effect of restriction of placental growth on umbilical and uterine blood flows

Endometrial caruncles were excised from sheep (caruncle sheep) before pregnancy. The effect of this on umbilical and uterine blood flows in a subsequent pregnancy was examined. Thirteen caruncle and twelve control sheep with indwelling vascular catheters were studied at 121 and 130 days pregnancy. In caruncle sheep, fetal, placental, and total uterine content weights were significantly lower than in control sheep. Six caruncle sheep carried normal-sized fetuses (weight within +/- 2 SD of mean weight for control fetuses) and seven carried small fetuses (weight greater than +/- 2 SD below mean weight for control fetuses). Mean weights of placentas in these groups were 0.290 +/- 0.067 and 0.156 +/- 0.069 kg, respectively, compared with 0.459 +/- 0.157 kg in control sheep. In small caruncle fetuses, umbilical and uterine blood flows and placental antipyrine clearance were significantly lower than in controls at 121 and 130 days gestation. Only umbilical blood flow was reduced in normal-sized caruncle fetuses. Umbilical blood flow and placental antipyrine clearance increased with gestational age in control sheep but not in sheep with normal-sized or small caruncle fetuses. In all sheep, umbilical and uterine blood flows and antipyrine clearance correlated with placental weight. Umbilical blood flow per kilogram of placenta but not uterine blood flow per kilogram of placenta correlated inversely with placental weight. Fetal weight at 130 days generally correlated with placental weight, umbilical and uterine blood flows, and antipyrine clearance in a curvilinear fashion such that fetal weight was not greatly restricted until these variables were less than or equal to 65% of control values.

Effect of Hypoxia on the Initiation of Secondary Wool Follicles in the Fetus

The development of secondary wool follicles in single fetal sheep subjected to hypobaric hypoxaemia was studied. One group of pregnant ewes were exposed to 57� 1 kPa from 30 to 135 days gestation. Fetal weights (mean � s.d.) for the hypoxaemic group (3' 35 � O' 53 kg; n = 4) were significantly lower than for the controls (4'19 � 0'31 kg; n = 3, P < 0'05). At 110 days gestation, a second group had arterial and venous catheters surgically implanted into the ewe and fetus and skin samples were taken from the fetus. At 120 days gestation (10 days after surgery) these animals were subjected to hypoxia for 20 days, at a level to maintain fetal carotid p02 between 1�47 and 1�87 kPa (mean carotid p02 for the control fetuses was 2�84 � 0�28 kPa). Fetal weight at 140 days was not significantly different in the hypoxaemic and control groups. Morphometric analysis revealed that the secondary to primary follicle ratio (S : P) was less in both groups of hypoxaemic fetuses than in their respective controls. Although hypoxia for 20 days did not significantly alter fetal weight, it produced a low S : P ratio similar to the longer-term hypoxaemic animals. It is concluded that hypoxia has a marked effect in reducing the initiation of secondary follicles in the last third of gestation.

The glioblastoma multiforme in Georgia, 1977-1981

To characterize the incidence and mortality of the glioblastoma multiforme as it is seen at the primary care level, a retrospective study was done through the Georgia Tumor Registry on 299 patients with histologically confirmed supratentorial glioblastoma multiforme. Specifically, the age incidence distribution, sex ratio, and the postoperative survivals were studied. The Registry also provided the opportunity to define the relative racial frequencies of this neoplasm in a large biracial population. The mean age of the patients at the time of surgery was 58.6 years and the age group having the highest incidence was 60 to 74 years. The overall ratio of affected males to females was 1.04 to 1. The postoperative survival periods were considerably shorter than those reported from large cooperative clinical trials. The overall postoperative survivals at 12 and 24 months were only 22% and 4%, respectively. Advancing age had a strong negative relationship with the length of survival such that the 50% survival for patients less than 30 years of age was 17 months, for those age 30 to 44 years it was 10.2 months, for those age 45 to 59 it was 5.8 months, and for those older than 60 it was only 2.2 months. The study confirmed previous suggestions that the incidence of the neoplasm is considerably higher in whites. There were 2.3 glioblastomas in whites for every one in blacks. No difference was noted in the length of survival between whites and blacks.

Effect of restriction of placental growth on the concentrations of insulin, glucose and placental lactogen in the plasma of sheep

The effect of restricting placental growth on maternal glucose, insulin and placental lactogen was investigated in 16 ewes carrying singleton lambs. Uterine caruncles were removed from seven ewes (caruncle ewes) before pregnancy, resulting in reduced placental size and retarded intra-uterine fetal growth. The concentration of insulin in maternal plasma was similar in both control and caruncle ewes. The concentration of glucose was significantly higher in the caruncle than in the control ewes (3.26 +/- 0.15 (S.E.M.) mmol/l, number of observations (n) = 9, vs 2.75 +/- 0.1, n = 9, P less than 0.02, and 3.27 +/- 0.16, n = 7, vs 2.46 +/- 0.11, n = 12, P less than 0.001, for the carotid artery and utero-ovarian vein respectively). The concentration of ovine placental lactogen (oPL) in the utero-ovarian vein was reduced in the caruncle compared with the control ewes (283 +/- 65 micrograms/l, n = 8, and 705 +/- 106 micrograms/l, n = 18, P less than 0.02, respectively). Restriction of placental growth by removal of endometrial caruncles similarly reduced the concentrations of oPL in maternal arterial plasma (231 +/- 54 micrograms/l, n = 9, and 621 +/- 96 micrograms/l, n = 18, P less than 0.002). Production of oPL by the placenta was also reduced by limiting placental growth to 30 +/- 11 micrograms/min, n = 8, compared with 133 +/- 43 micrograms/min, n = 15, P less than 0.05, for the controls. Production of oPL per gram of placenta in the caruncle group, although only 34% of the control value, was not reduced significantly.(ABSTRACT TRUNCATED AT 250 WORDS)

Intrauterine growth retardation: clinical and experimental

Intrauterine growth retardation is a common and potentially hazardous problem for the fetus. Despite this, the obstetric factors associated with growth retardation have changed little in the last twenty years. Some of the other factors, the so-called behavioural factors should be amenable to correction through education or changing social circumstances. Experimental studies presented here support the clinical observations that the growth retarded fetus is often malnourished and/or hypoxaemic. Restriction of placental growth results in fetal growth failure and these fetuses are chronically hypoxaemic and hypoglycaemic. Furthermore the apparent margin of safety between the delivery to and consumption by the fetus is less for the small fetuses. We suggest that this reduction in supply results in the endocrine changes and that these in turn, modulate the pattern of fetal growth.

Isolation and quantitation of carbohydrates in sheep plasma by high-performance liquid chromatography

The application of ultraviolet detection at 190 nm following chromatography on a Ca2+ cation-exchange column with a mobile phase of water enables the low amounts of carbohydrates present in plasma to be quantitated. The separation and quantitation of carbohydrates in maternal and fetal sheep plasma and amniotic fluid are described, as is the application of this method to the determination of specific radioactivities of glucose and fructose in plasma.

Inhibitory effects on steroid production from isolated adrenal cells of rhesus monkey (Macaca mulatta) of pro-opiomelanocorticotrophic peptides

Adrenal glands from Rhesus monkeys (Macaca mulatta) of 160 days gestation, newborn, 2 months-old infants or 6 months-old infants were excised and prepared, by a collagenase digestion, as a cell suspension. The cells were incubated with 10 pg/ml, 100 pg/ml or 1 ng/ml of a peptide of the ACTH/pro-opiomelanocortin 'family', 57K, 31K, 20K, alpha MSH, ovine-CLIP or gamma LPH either in the presence or absence of 166 pg/ml ACTH1-39. The production by cortisol and androstenedione was measured by radioimmunoassay. Using the steroid production by aliquots of the cell suspension with either no stimulating agent or ACTH1-39 alone as controls, the net influence of these different peptides on basal or ACTH1-39-stimulated production was observed. alpha MSH, ovine-CLIP and gamma LPH had no influence on either basal or stimulated cortisol or androstenedione production. Corticotrophic peptides of 57K, and 20K and pro-opiomelanocortin each had a steroidogenic activity alone, in all age groups. In the fetal and newborn monkeys' adrenal cells, peptides of 57K and 20K at 1 ng/ml had an inhibitory influence on ACTH1-39 stimulated cortisol and androstenedione production. The influence of the 20K peptide is partially inhibitory as the steroidogenic potential of this peptide is not additive with that of ACTH1-39. These results show that, as observed in other species, that the ACTH/pro-opiomelanocortin range of peptides are inhibitory to the action of ACTH1-39 in the developing adrenal.

Symphysial-fundal height from 12 weeks' gestation

There is a strong association between birth-weight and perinatal mortality and morbidity. Intrauterine growth retardation (IUGR) is an important cause of perinatal morbidity and mortality and 50% of cases occur in low risk patients. Despite an obvious need, the diagnosis of IUGR by clinical means has remained difficult and inaccurate. To aid this diagnosis a graph of symphysial-fundal height, based on a local population in Australia, is presented. When used in conjunction with standard charts showing centiles of birth-weight for gestational age, an estimate of fetal weight may be simply and quickly made. When tested in 49 pregnancies the mean error of predicted birth-weight was 86 +/- 67 gm/Kg.

ACTH control of steroid secretion from adrenal cells of the developing rhesus monkey (Macaca mulatta)

Cells from adrenal glands of 140-160 days foetal, neonatal and infant Rhesus monkeys (Macaca mulatta) were prepared, by collagenase digestion and incubated with 10 pg-16 ng/ml ACTH. The production of cortisol, androstenedione, corticosterone, progesterone and prostaglandins was measured. The cortisol production in the 140 day and 160 day foetuses and in the neonatal adrenal cells was comparable. It was 2-fold higher in adrenal cells of 6 month infant monkeys. In all the groups there was an increasing production of cortisol with increasing ACTH concentration, and a response to low physiological concentrations of ACTH. The androstenedione production was significantly greater in the 160 day foetuses than in either those of 140 days or of the neonate which demonstrated a poor response to increasing ACTH concentrations. It responded well to increasing ACTH in adrenal cells from 6 month infant monkeys. Corticosterone output was 1/10th of cortisol with only the 140 day foetuses showing an increase in production with increasing ACTH concentrations. The results demonstrate that cells of the primate foetal adrenal gland are not inherently unresponsive to ACTH stimulation as regards cortisol production, which per/micrograms DNA does not appear to change over the last 25 days before term.

Concentrations of prolactin in the plasma of fetal sheep and in amniotic fluid in late gestation and during dexamethasone-induced parturition

The concentration of prolactin in samples of fetal plasma and amniotic fluid collected from sheep with indwelling catheters has been measured by radioimmunoassay. There was considerable variation between animals in the concentration of prolactin in fetal plasma which ranged from less than 2 micrograms/l to greater than 50 micrograms/l. In five out of eight fetuses which were sampled at intervals throughout the last 30 days of pregnancy, there was an increase in the concentration of prolactin in the plasma before parturition. The concentration of prolactin in amniotic fluid was consistently low (approximately 1 microgram/l). Induction of premature parturition by intrafetal infusion of dexamethasone was accompanied by an increase in the concentration of prolactin in only one of three fetuses infused. These results indicated that prolactin is present in fetal plasma but that an increase in prolactin in fetal plasma before the onset of parturition does not always occur. The low concentration of prolactin in amniotic fluid contrasts with the high concentrations of this hormone found in the amniotic fluid of the primate.

Ovine placental lactogen concentrations during premature delivery induced by infusion of dexamethasone or adrenocorticotrophin to the fetus

Premature delivery was induced by intrafetal infusion of dexamethasone or (1-24)ACTH, starting between days 124 and 129 of pregnancy in twelve ewes carrying intact (n = 7) or hypophysectomized (n = 5) single fetuses. Concentrations of ovine placental lactogen (oPL) in maternal plasma were measured by specific radioimmunoassay before and during premature delivery. There was no significant change in oPL concentrations before delivery in ewes carrying either intact or hypophysectomized fetuses. The results suggest that a prepartum decline in oPL is not an essential prerequisite for delivery, and indicate that fetal glucocorticoids are not directly responsible for the prepartum fall in oPL concentrations observed at spontaneous delivery.

The regulation of ovine placental lactogen the role of the fetal hypothalamic-pituitary axis

The possible rôle of the fetal hypothalamic-pituitary axis in regulating the secretion of ovine placental lactogen (oPL) was investigated in chronically-catheterised ewes and fetuses in late pregnancy. Intravascular administration of agents to fetuses that significantly increased fetal prolactin concentrations (chlorpromazine 6.25 mg;thyrotrophin releasing hormone, 10 micrograms), significantly reduced fetal prolactin concentrations (bromocriptine, 0.033 mg/h), or significantly reduced fetal growth hormone (GH) concentrations (somatostatin, 2.5 micrograms/min), had no effect on maternal or fetal oPL concentrations. Mean fetal levels of prolactin or GH in late gestation could not be correlated with oPL concentrations, although fetal hypophysectomy prevented the normal prepartum fall in oPL concentrations.

Effect of intrauterine death and fetectomy on ovine placental lactogen production

Concentrations of ovine placental lactogen (oPL) were measured in the peripheral plasma of six ewes after the removal of fetuses (in four ewes) or after the intrauterine death of one of twin fetuses (in two ewes). Concentrations of oPL decreased after fetectomy or intrauterine fetal death, indicating that a living fetus is essential to the sustained secretion of oPL.