Sonographic determination of fetal size from 20 weeks of gestation onward correlates with birth weight.

OBJECTIVE: To evaluate the clinical efficacy of ultrasonographic measurement of fetal weight, estimated fetal weight (EFW) was analyzed in relation to birth weight. METHOD: Data were collected retrospectively from the medical records of 548 term pregnancies unassociated with fetal malformations. The subjects underwent sonographic examinations from 20-23 weeks onward at 4 weeks intervals for the estimation of EFW. Subjects were divided into 6 subgroups based on birth weight deviation (BWD) (A: - 3.0 < or = BWD < -2.0; B: -2.0 < or = BWD < -1.5; C: -1.5 < or = BWD < -1.0; D: - 1.0 < or = BWD < -0.5; E: -0.5 < or = BWD < + 0.5 and F: + 0.5 < or = BWD). Distribution and changes in EFW deviation (EFWD) with gestational age were analyzed related to BWD. RESULT: A difference in fetal growth based on EFWD was noted in small for gestational age (SGA) cases compared to non-SGA cases, and the difference was observed as early as 20-23 weeks. EFWD was significantly correlated with BWD from 20-23 weeks to term. CONCLUSION<==: Sonographic determination of fetal growth from 20 weeks of gestation onward correlated with birth weight deviation, and this emphasized the clinical value of evaluating fetal growth during the latter half of pregnancy.

Increase in prostaglandin H synthase 2, but not prostaglandin F2alpha synthase mRNA in intrauterine tissues during betamethasone-induced premature labor and spontaneous term labor in sheep.

OBJECTIVE: Prostaglandin F synthase (PGFS) catalyzes reduction of prostaglandin H(2) to PGF2alpha. No information exists on PGFS expression and regulation during pregnancy, either mRNA or protein, in relation to labor in uterine tissues in any species. We characterized PGFS mRNA expression in ovine myometrium, endometrium, maternal and fetal placenta in betamethasone-induced premature labor and spontaneous term labor using our cloned ovine PGFS riboprobe. Prostaglandin H synthase (PGHS) 2 mRNA was evaluated simultaneously as a control whose pregnancy related changes are well known. METHODS: Poly-A or total RNA from fetal placenta, myometrium, and endometrium in control ewes at 143-147 days of gestational age (dGA, TCNL, n = 6), and ewes in spontaneous term labor at 145-147 dGA (STL, n = 6) and endometrium and maternal and fetal placenta in early control ewes not in labor (ECNL, n = 6) and betamethasone induced labor at 128-135 dGA (BL, n = 6) were analyzed for PGHS2 and PGFS mRNA. RESULTS: PGFS mRNA did not change at spontaneous term labor in myometrium, endometrium, and fetal placenta. PGFS mRNA decreased during betamethasone-induced premature labor in endometrium and maternal placenta (P < .05), but remained unchanged in fetal placenta and myometrium. PGHS2 mRNA increased in endometrium, placenta, and myometrium during betamethasone-induced premature labor and spontaneous term labor. CONCLUSION: Increased PGHS2, but not PGFS mRNA was tightly associated with the onset of betamethasone-induced premature labor as well as spontaneous term labor in the endometrium, placenta, and myometrium. Transcription of PGFS mRNA may not be the rate-limiting step in the pathway contributing to increased PGF(2alpha) at labor.

Interpolation of missing part of human follicle border on ultrasonic B-mode image by iterative revision.

In clinical infertility treatments, assessment of ovarian follicle growth by ultrasonography is important. In order to measure the geometrical characteristics of the human follicle, such as the area of the cross-sectional image and the volume inside the follicle, a method based on manual tracing of the follicle contour from the ultrasonic B mode image is widely used. However, the observable ultrasonic B mode images are sometimes imperfect and some parts of the follicle border are missing due to the existence of the acoustic shadow. In this paper, a method that interpolates the missing part of the follicle border from the known part is proposed. This method uses a priori information of the follicle, which is usually known in actual cases: (1) the follicle's surface is so smooth that its border is assumed to be a smooth closed curve; and (2) the position of the follicle's center is roughly predicted in advance in the ultrasonic B-mode image. In the proposed method, the missing part of the human follicle border is interpolated from the known part by applying an iterative revision so as to satisfy the smoothness condition of the follicle. This method is also applied to three-dimensional image reconstruction of the human follicle.

Prenatal detection of a high-risk group for intrauterine growth restriction based on sonographic fetal biometry.

OBJECTIVE: This study was performed to evaluate the significance of sonographic fetal biometry in predicting low birth weight. METHOD: Five hundred and sixty-eight single-term pregnancies were analyzed. They were stratified into seven subgroups by birth weight deviation (BWD). Among the 568 pregnancies, 115 were revealed to be small-for-gestational-age (SGA) (birth weight less than mean -1.5 S. D.). When IUGR was suspected by routine sonographic fetal biometry, 'IUGR work-up' was carried out. The diagnostic performance of our screening method for the detection of SGA pregnancies in the general population was calculated. RESULT: The sensitivity, specificity, positive predictive value, negative predictive value and odds ratio of our screening method for the detection of SGA pregnancies in the general population were 73.0, 96.6, 83.2, 98.0% and 131.0, respectively. CONCLUSION: These data suggest that sonographic biometry is useful for the prenatal detection of high-risk cases of fetal growth restriction.

Autologous blood transfusion in patients with hepatocellular carcinoma undergoing hepatectomy.

BACKGROUND: Homologous blood transfusion (HBT) has the risk of an immunosuppressive effect and may adversely affect the prognosis of patients with carcinomas. Autologous blood transfusion (ABT) has not yet become a standard procedure in gastroenteric cancer surgery. We investigated the usefulness and problems of ABT combined with the use of recombinant human erythropoietin (rh-EPO). METHODS: An evaluation of autologous blood transfusion (ABT) combined with recombinant human erythropoietin (rh-EPO) treatment was conducted in 46 patients with hepatocellular carcinoma undergoing hepatectomy. Preoperative autologous blood donation (ABD) was accomplished for 25 of the 46 patients. The preoperative changes in hemoglobin and hematocrit in relation to route of administration of erythropoietin were studied. In addition, intraoperative blood requirements and the postoperative complications for patients who predonated were compared with those of patients who underwent surgery without autologous predonation. RESULTS: The proportion of patients not requiring additional homologous blood transfusions (HBT) during operation was significantly higher in the ABD group than in the non-ABD group (88% versus 38%). The incidence of postoperative complications was significantly higher in patients receiving HBT than in nontransfused patients and in those receiving ABT. CONCLUSIONS: Preoperative autologous blood donation in combination with rh-EPO therapy markedly reduced the requirement for homologous blood transfusion during surgery in patients with hepatocellular carcinoma having hepatectomy.

Increased myometrial contracture frequency at 96-140 days accelerates fetal cardiovascular maturation.

Fetal cardiovascular responses to an altered intrauterine environment of increased myometrial contractures induced by oxytocin (OT) pulses to the ewe over the final 50 days of gestation were studied in chronically instrumented sheep. Ewes received saline (Cntl) or long-term OT treatment (LTOT, 600 microU x kg(-1) x min(-1) in 5-min pulses every 20 min) from 96 days gestational age. Fetal baroreflex responses to sodium nitroprusside (SNP) and phenylephrine (PE) were studied at 133 days gestation. OT increased contractures in LTOT ewes. Fetal blood pressure (FBP) was higher, and fetal heart rate (FHR) and slope of daily change in FBP and FHR were lower in LTOT fetuses. Fetal SNP-induced hypotension resulted in a narrow R-R interval variation range in LTOT fetuses; Cntl fetuses showed early breakdown in compensation. Baroreflex response slope during PE-induced fetal hypertension was lower in LTOT than in Cntl fetuses. Although the cortisol-to-ACTH ratio was lower in LTOT fetuses, fetal plasma ACTH and cortisol changes were similar in control and LTOT fetuses. We hypothesize that contracture-induced alterations in the intrauterine environment accelerate fetal cardiovascular development through mild hypoxemia, repetitive fetal pituitary-adrenal stimulation, and/or physical stimulation.

Differential expression of myometrial oxytocin receptor and prostaglandin H synthase 2, but not estrogen receptor alpha and heat shock protein 90 messenger ribonucleic acid in the gravid horn and nongravid horn in sheep during betamethasone-induced labor.

In the present study, we characterized four myometrial contraction-associated proteins (mCAPs): oxytocin receptor (OTR), prostaglandin H synthase 2 (PGHS2), estrogen receptor alpha (ERalpha), and heat shock protein 90 (Hsp90) messenger RNA (mRNA) expression in the nongravid horn of pregnant sheep and compared them with their expression in the gravid horn that is exposed to a greater degree of stretch. We also examined the regulatory effects of estrogen and progesterone on OTR mRNA expression in ovariectomized nonpregnant sheep. In addition, we determined the ontogeny of mCAP expression in the gravid horn throughout late pregnancy and during spontaneous term labor. Gravid horn and nongravid horn myometria were removed under general anesthesia from control ewes not in labor at 130-140 days gestational age (dGA; n = 3) and during betamethasone-induced labor (n = 6) at the same gestational age. Gravid horn myometrium was also collected from ewes not in labor at 95 dGA (n = 3), 101-110 dGA (n = 3), 111-120 dGA (n = 3), 121-130 dGA (n = 3), 131-140 dGA (n = 3), and 141-145 dGA (n = 4) and from ewes in spontaneous term labor (n = 4). All ewes were carrying single fetuses. Myometrium was also collected from ovariectomized nonpregnant ewes treated with saline (n = 5), estradiol (50 microg/day; n = 5), progesterone (0.3 g, intravaginally; n = 5), and estradiol plus progesterone (n = 5). Myometrial RNA was extracted and analyzed by Northern blot for OTR, PGHS2, ERalpha, and Hsp90 mRNA, normalized for 18S ribosomal RNA or beta-actin. ERalpha, Hsp90, OTR, and PGHS2 mRNA were all significantly up-regulated during betamethasone-induced labor (P < 0.01) in gravid and nongravid horn myometrium. The level of gravid horn OTR mRNA during labor was 3 times the level of nongravid horn OTR mRNA (P < 0.0001). Gravid horn PGHS2 mRNA was also higher than nongravid horn PGHS2 (P < 0.02). In contrast, in spontaneous term labor nongravid horn, ERalpha and Hsp90 mRNA were similar to gravid horn. Myometrial ERalpha and Hsp90 mRNA remained unchanged throughout late pregnancy and increased at spontaneous term labor (P < 0.05). In contrast, myometrial OTR increased around 130 dGA (P < 0.01) and further increased at spontaneous term labor (P < 0.02). Progesterone significantly inhibited myometrial OTR mRNA expression in nonpregnant sheep and estradiol antagonized progesterone's inhibitory effect. Mechanical stretch differentially regulated mCAP mRNA expression in the ovine gravid horn and nongravid horn. Mechanical stretch appears largely responsible for increased OTR mRNA and to a lesser degree PGHS2 mRNA. In addition, endocrine factors may be required for full activation of OTR and PGHS2 mRNA associated with labor. ERalpha and Hsp90 mRNA are not under the control of uterine stretch in keeping with our previous results, indicating that systemic hormones such as estradiol, are prime regulators for these two mCAP mRNA expression during labor.

Tidal volume amplitude affects the degree of induced bronchoconstriction in dogs.

When isolated constricted airway smooth muscle is oscillated, muscle tone decreases. We investigated whether changing tidal volume (VT) would affect induced bronchoconstriction in an in vivo canine model. Open-chest dogs were intubated with a double-lumen endotracheal tube, which isolated each main bronchus, and mechanically ventilated with a dual-cylinder ventilator. Bronchial pressure (Pbr) and flow were measured separately in each lung. Resistance and elastance were calculated by fitting the changes in Pbr, flow, and volume to the equation of motion. After baseline measurements at the same VT (150 ml), the two lungs were ventilated with different VT (50 vs. 250 ml) at a constant positive end-expiratory pressure. A continuous infusion of methacholine was begun, and measurements were repeated. The two lungs were then ventilated with the same VT (250 ml), and measurements were again repeated. A similar protocol was performed in a second group of dogs in which mean Pbr was kept constant. Bronchoconstriction was more severe in the lung ventilated with lower VT in both protocols. When VT was reset to the same amplitude in the two lungs, the difference in bronchoconstriction was abrogated. These results demonstrate that large VT inhibits airway smooth muscle contraction, regardless of mean Pbr.

Alteration of fetal oxygenation and responses to acute hypoxemia by increased myometrial contracture frequency produced by pulse administration of oxytocin to the pregnant ewe from 96 to 131 days' gestation.

OBJECTIVES: This study examined the effects of increased myometrial contracture frequency from 96 to 131 days' gestation on ovine fetal oxygen transport and physiologic response to acute hypoxemia. STUDY DESIGN: Ten pregnant ewes received either saline solution (control, n = 5) or long-term administration of oxytocin (600 microU. kg-1. min-1) in 5-minute pulses every 20 minutes to the maternal jugular vein beginning at 96 days' gestation (n = 5). Maternal tracheal tubes, fetal carotid artery and jugular vein catheters, and electrocorticographic and electromyographic electrodes were placed with the animals under halothane general anesthesia at 122 days' gestation. At 131 days' gestation fetal hypoxemia was induced for 1 hour. Maternal and fetal arterial blood gas samples were obtained at 60, 15, and 5 minutes before the start of hypoxemia and at 5, 10, 20, 30, 40, 60, and 120 minutes after the start of hypoxemia. RESULTS: Baseline PO2 before hypoxemia was significantly lower and oxygen content was significantly higher in fetuses in the long-term oxytocin group than in control fetuses. At the end of hypoxemia the fetal pH, oxygen saturation, and oxygen content were significantly higher in the long-term oxytocin group than in the control group, although PO2 did not differ between groups. The fetal blood oxygen dissociation curve was shifted to the left in the long-term oxytocin group. During hypoxemia the absolute fetal blood pH was higher and the blood pH variation was lower in long-term oxytocin group than in the control group. Lower baseline and hypoxia-induced fetal plasma cortisol concentrations were observed in fetuses in the long-term oxytocin group than in fetuses of control ewes. CONCLUSION: Increased contracture frequency during a period of 35 days shifts the fetal oxygen dissociation curve toward the left and alters fetal response to acute hypoxemia.

Inhalation anaesthetics produce asynchronous reversal of ventilation inhomogeneity and increased lung resistance in a canine model of bronchial asthma.

Bronchial asthma is characterized by not only an increase in lung resistance but also inhomogeneous ventilation. We aimed to investigate how two inhalation anaesthetics, isoflurane and sevoflurane, relieve ventilation inhomogeneity and reduce lung resistance in the bronchoconstricted lung. We provoked bronchoconstriction in dogs by a continuous i.v. infusion of methacholine, then administered either isoflurane or sevoflurane. Ventilation inhomogeneity was quantified by the difference in respiratory phases between the regional alveolar pressures measured at two distinct lobes. We constructed a mathematical model that simulated our experimental results. Both anaesthetics decreased lung resistance (P < 0.01). Isoflurane significantly reduced the indices of inhomogeneity (P < 0.01). Sevoflurane exerted only a tendency to reduce uneven ventilation. Our model simulation suggested that the anaesthetics reduced ventilation inhomogeneity in preference to lung resistance when the dogs suffered from severe bronchoconstriction.

Effect of time-varying load on degree of bronchoconstriction in the dog.

It is well established that the degree of airway smooth muscle shortening produced by a given dose of bronchial agonist is greatly affected by lung volume. The airways are tethered by parenchymal attachments, the tension of which increases progressively with lung volume, thereby presenting a commensurately increasing hindrance to smooth muscle contraction. Earlier studies (P. F. Dillon, M. O. Aksoy, S. P. Driska, and R. A. Murphy. Science 211: 495-497, 1981) presented evidence that smooth muscle contraction initially involves rapidly cycling cross bridges, which then change to noncycling (latch) bridges. They also suggested that most of the muscle shortening occurs during the early rapid cross-bridge phase. This implies that smooth muscle subject to a given load early in contraction should shorten less than when it is subject to the same load later on. An in vitro study (W. Li and N. L. Stephens. Can. J. Physiol. Pharmacol. 72: 1458-1463, 1994) obtained support for this notion. To test this hypothesis in vivo, we measured the changes in lung impedance at 1 and 6 Hz produced in dogs by a bolus intravenous injection of methacholine when lung volume was increased for 10 s at different times after injection. We found that the changes in mechanics were greatly inhibited, whereas lung volume was elevated. However, when lung volume was returned to its initial level, the lung mechanics continued to change at a rate unaffected by the preceding volume change. We conclude that temporary mechanical inhibition of airway smooth muscle shortening in the normal dog in vivo merely delays an otherwise normal course of contraction.

Electrocortical activity in fetal sheep in the last seven days of gestation.

1. Electrocorticogram (ECoG) and myometrial electromyogram (EMG) were recorded continuously in chronically instrumented late gestation sheep fetuses (n = 9) to analyse: (1) 24 h ECoG patterns, (2) relationships between ECoG and myometrial contractility, and (3) 24 h ECoG patterns at the spontaneous onset of labour. 2. Spontaneous onset of labour was determined from the myometrial EMG. ECoG signals were purified by a denoising procedure of wavelet decomposition. High-voltage slow ECoG activity (HV) and low-voltage fast ECoG activity (LV) were determined mathematically, and HV-LV cycle periodicity was calculated by periodogram analysis. 3. Twenty-four hour rhythms were present in fetal ECoG HV-LV cycles in the 3-5 days prior to spontaneous onset of labour (P < 0.01). Cycle frequency was lower at 08.00-12.00 h and higher at 16.00-20.00 h (lights on at 07.00 h, lights off at 21.00 h). LV duration was longer at 20.00-24.00 h, and HV was shorter at 16.00-20.00 h. No relationship was found between ECoG cycles and myometrial contracture cycles. Twenty-four hour ECoG rhythms disappeared 1 day before the spontaneous onset of labour. 4. ECoG patterns changed 7 to 4 h prior to spontaneous onset of labour, percentage of time spent and duration of HV ECoG increased, and percentage of time spent in LV decreased significantly. ECoG HV-LV cyclicity was reduced 4-5 h prior to spontaneous onset of labour, indicating that the altered fetal hormonal and blood gas environment around the spontaneous onset of labour alter fetal neural function.

Isovolume bronchoconstriction by vagal stimulation in dogs: effects of lung inflation pressure.

The changes elicited in lung mechanics by a given stimulus to the airway smooth muscle depend significantly on end-expiratory lung volume. However, the precise quantitative relationship between volume (or inflation pressure) and airway responsiveness remains to be elucidated. We measured the changes in lung elastic recoil pressure and impedance at 1 and 8 Hz, produced in anesthetized, paralyzed, open-chest dogs over periods of 32 sec, when the vagus nerves were continuously electrically stimulated at constant lung volume. The increases in lung elastic recoil pressure increased with PEEP, which we interpret as being due to parenchymal distortions produced by the contracting airways acting against parenchymal attachment forces that increase with lung volume. In contrast, the increases in lung resistance at 1 and 8 Hz and elastance at 1 Hz all decreased by several-fold as PEEP was increased, which we interpret as reflecting the decreased airway smooth muscle shortening that was achieved with increasing parenchymal load.

Electrical impedance tomography can monitor dynamic hyperinflation in dogs.

We assessed in eight dogs the accuracy with which electrical impedance tomography (EIT) can monitor changes in lung volume by comparing the changes in mean lung conductivity obtained with EIT to changes in esophageal pressure (Pes) and to airway opening pressure (Pao) measured after airway occlusion. The average volume measurement errors were determined: 26 ml for EIT; 35 ml for Pao; and 54 ml for Pes. Subsequently, lung inflation due to applied positive end-expiratory pressure was measured by EIT (delta VEIT) and Pao (delta VPAO) under both inflation and deflation conditions. Whereas delta VPAO was equal under both conditions, delta VEIT was 28 ml greater during deflation than inflation, indicating that EIT is sensitive to lung volume history. The average inflation delta VEIT was 67.7 +/- 78 ml greater than delta VPAO, for an average volume increase of 418 ml. Lung inflation due to external expiratory resistance was measured during ventilation by EIT (delta VEIT,vent) and Pes (delta VPes,vent) and at occlusion by EIT (delta VEIT,occl), Pes, and Pao. The average differences between EIT estimates and delta VEIT,occl were 5.8 +/- 44 ml for delta VEIT,vent and 49.5 +/- 34 ml for delta VEIT,occl. The average volume increase for all dogs was 442.2 ml. These results show that EIT can provide usefully accurate estimates of changes in lung volume over an extended time period and that the technique has promise as a means of conveniently and noninvasively monitoring lung hyperinflation.