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PubMed2002

Native and recombinant proguanylin feature identical biophysical properties and are monomeric in solution.

Guanylin, an intestinal peptide hormone and endogenous ligand of guanylyl cyclase C, is produced as the corresponding prohormone proguanylin. The mature hormone consists of 15 amino acid residues, representing the COOH-terminal part of the prohormone comprised of 94 amino acid residues. Here we report the recombinant expression and purification of proguanylin with its native disulfide connectivity, as well as the biophysical characterization of the recombinant and native protein. The comparison of recombinant and native proguanylin revealed identical biophysical and structural properties, as deduced from CZE, HPLC, and mass spectrometry, as well as NMR spectroscopy and CD spectroscopy at various temperatures and pH values. Exhaustive analytical ultracentrifugation studies were employed for protein concentrations up to the millimolar range to determine the association state of recombinant as well as native proguanylin, revealing both proteins to be monomeric at the applied solution conditions. As a result, a former identified close proximity between the termini of proguanylin is due to intramolecular interactions.

Amino Acid Sequence↗
PubMed1999

Biophysical approaches to G protein-coupled receptors: structure, function and dynamics.

G protein-coupled receptors (GPCR) represent a large family of drug targets for which there is no high resolution structural information. In order to understand the mechanisms of ligand recognition and receptor activation, there is a strong need for novel biophysical methods. In this Perspective we provide an overview of recent experimental approaches used to explore the molecular architecture and dynamics of GPCR and their interactions with ligands and G proteins using biophysical, non-crystallographic, methods.

Electron Spin Resonance Spectroscopy↗
PubMed2001

Conformation and other biophysical properties of cyclic antimicrobial peptides in aqueous solutions.

As a step towards understanding the mechanism of the biological activity of cyclic antimicrobial peptides, the biophysical properties and conformations of four membrane-active cyclic peptide antibiotics, based on gramicidin S (GS), were examined in aqueous environments. These cyclic peptides, GS10 [cyclo(VKLdYP)2], GS12 [cyclo(VKLKdYPKVKLdYP)], GS14 [cyclo(VKLKVdYPLKVKLdYP)] and [d-Lys]4GS14 [cyclo(VKLdKVdYPLKVKLdYP)] (d-amino acid residues are denoted by d and are underlined) had different ring sizes of 10, 12 and 14 residues, were different in structure and amphipathicity, and covered a broad spectrum of hemolytic and antimicrobial activities. GS10, GS12 and [d-Lys]4GS14 were shown to be monomeric in buffer systems with ionic strength biological environments. GS14 was also monomeric at low concentrations, but aggregated at concentrations > 50 microm. The affinity of peptides for self-assembly and interaction with hydrophobic surfaces was related to their free energy of intermolecular interaction. The effects of variations in salt and organic solvent (trifluoroethanol) concentration and temperature on peptide conformation were also examined. Similar to GS, GS10 proved to have a stable and rather rigid conformation in different environments and over a broad range of temperatures, whereas GS12, GS14 and [d-Lys]4GS14 had more flexible conformations. Despite its conformational similarity to GS10, GS14 had unique physicochemical properties due to its tendency to aggregate at relatively low concentrations. The biophysical data explain the direct relation between structure, amphipathicity and hydrophobicity of the cyclic peptides and their hemolytic activity. However, this relation with the antimicrobial activity of the peptides is of a more complex nature due to the diversity in membrane structures of microorganisms.

Anti-Bacterial Agents↗
PubMed2000

Biophysical measurements of human forearm skin in vivo: effects of site, gender, chirality and time.

BACKGROUND/AIMS: Measurements of transepidermal water loss (TEWL) and skin colour are biophysical techniques commonly used to measure the in vivo skin effects of cosmetics, topical medicaments and chemical irritants. The purpose of this study was to investigate the variability of TEWL and skin colour on human forearm skin as a function of regional variation, gender and preferred chirality over an 8 h period. METHODS: Biophysical measurements of TEWL and skin colour were made at five sites on both forearms of male (n=8) and female (n=9) human volunteers in vivo (38% relative humidity, 21 degrees C). RESULTS: Rates of TEWL at the forearm midpoint were 10% lower than at the forearm extremities (P<0.01). Skin redness (a*) near the wrist was 5-10% higher than at other sites (P<0.05). Rates of TEWL were 5% higher in male volunteers (P<0.05). Red and blue (b*) colour measurements of male forearm skin differed by 18% and 20% in comparison with female, respectively. Rates of TEWL, skin brightness (L*) and b* decreased by 9% (P<0.05), 1.8% (P<0.05) and 4% (P<0.05), respectively, with time whereas a* and skin temperature increased by 4.5% (P<0.01) and 7.2% (P<0.01), respectively. There was a significant correlation between the change in all measured parameters with time. CONCLUSIONS: Significant differences in TEWL and skin colour were identified that may have relevance in the design and interpretation of multivariate analyses of human forearm skin. Diurnal variation of TEWL, skin colour and temperature may have a single underlying mechanism.

Journal Article↗
PubMed2003

Skin biophysical properties of a population living in Valais, Switzerland.

BACKGROUND/PURPOSE: Switzerland has one of the highest rates of skin diseases and particularly skin cancer, in Europe. Skin elastosis, roughness and atopy are also frequent. High UV exposure and prevalence of light skin individuals could be the cause. Valais, in Southern Switzerland, is a mountain region with elevated sun irradiation and low air humidity, an ideal location to study the effect of the environment and life style on skin biophysical characteristics. The purpose of the study was to measure skin biophysical parameters non-invasively on healthy subjects living in Valais, and to correlate the measures with their life style. METHODS: One hundred and ten women were examined between October 2001 and February 2002. Measures of skin hydration, sebum content, pH and visco-elasticity were taken in a closed environment with constant temperature and controlled air humidity, utilizing commercially available non-invasive devices. Subjects were interviewed using a questionnaire and data on personal traits and life style were collected. Correlations between subject's skin parameters and life style were statistically examined. RESULTS: On average we observed low values of skin capacitance that identify subjects with dry skin. Measures of skin visco-elasticity ratios were also particularly low, while skin pH and sebum content were in the normal range. Age was correlated with a decrease of skin elasticity and sebum content, but there was no correlation with hydration or pH. CONCLUSIONS: We confirm, as reported in other studies, the effect of age on skin elasticity and sebum content and we identify, for the first time, a region with a population characterized by particularly low levels of skin hydration and skin visco-elasticity. Although people examined were free of skin diseases, we believe that protection from the sun and treatment of skin with hydrating products need to be emphasized as a prevention strategy, in regions such as Valais, with high sun irradiation and low humidity.

Adolescent↗
PubMed2004

Identification and biophysical characterization of a very-long-chain-fatty-acid-substituted phosphatidylinositol in yeast subcellular membranes.

Morphological analysis of a conditional yeast mutant in acetyl-CoA carboxylase acc1ts/mtr7, the rate-limiting enzyme of fatty acid synthesis, suggested that the synthesis of C26 VLCFAs (very-long-chain fatty acids) is important for maintaining the structure and function of the nuclear membrane. To characterize this C26-dependent pathway in more detail, we have now examined cells that are blocked in pathways that require C26. In yeast, ceramide synthesis and remodelling of GPI (glycosylphosphatidylinositol)-anchors are two pathways that incorporate C26 into lipids. Conditional mutants blocked in either ceramide synthesis or the synthesis of GPI anchors do not display the characteristic alterations of the nuclear envelope observed in acc1ts, indicating that the synthesis of another C26-containing lipid may be affected in acc1ts mutant cells. Lipid analysis of isolated nuclear membranes revealed the presence of a novel C26-substituted PI (phosphatidylinositol). This C26-PI accounts for approx. 1% of all the PI species, and is present in both the nuclear and the plasma membrane. Remarkably, this C26-PI is the only C26-containing glycerophospholipid that is detectable in wild-type yeast, and the C26-substitution is highly specific for the sn-1 position of the glycerol backbone. To characterize the biophysical properties of this lipid, it was chemically synthesized. In contrast to PIs with normal long-chain fatty acids (C16 or C18), the C26-PI greatly reduced the bilayer to hexagonal phase transition of liposomes composed of 1,2-dielaidoyl-sn-glycero-3-phosphoethanolamine (DEPE). The biophysical properties of this lipid are thus consistent with a possible role in stabilizing highly curved membrane domains.

Acyltransferases↗
PubMed1994

The biophysical profile as a tool for prediction of preterm delivery.

Our objective was to determine if any of the following parameters is a predictor of preterm delivery: gestational age, cervical dilatation, or biophysical profile score.Sixty-two women with certain dates, intact membranes, and preterm contractions more frequent than 300 min underwent a 30-min ultrasonographic assessment of fetal breathing movements, fetal tone, fetal movement and amniotic fluid volume, each of which was scored as 0, 1, or 2 before any tocolytics were given. The total score (0-8) was calculated and cervical dilatation was recorded. All women were subsequently placed on tocolytics. Data were analyzed using survival analysis with stepwise regression of the covariates to determine the predictive values of the total score, its individual parameters, gestational age, and cervical dilatation to the outcome variable of hours to delivery. Gestational age, cervical dilatation and time interval to delivery were categorized and entered into a logistic regression model with the total score and its components to determine predictive odds.Total score (p < 0.0001) and cervical dilatation (p < 0.0001) were the most significant variables associated with time interval to delivery, followed by gestational age (p = 0.035). When the individual biophysical parameters were entered into the model, fetal tone (p < 0.0001), cervical dilatation (p < 0.0001) and gestational age (p < 0.014) were the only variables related to time interval to delivery. Predictive odds of delivery in less than 48 h in relation to fetal tone and cervical dilatation were calculated. Total score, fetal tone, and cervical dilatation were strongly associated with time interval to delivery. Our study did not support fetal breathing movements as a predictor of preterm delivery.

Journal Article↗
PubMed1997

Needle Implantation Cryoprobes: Biophysical and Thermal Characteristics.

There has been increased recent interest in hepatic cryosurgery for primary and metastatic tumors in the liver. This has been realized through technological advances in intraoperative ultrasound monitoring and cryoprobe technology. Purpose-designed needle implantable cryoprobes have been developed to freeze deep-seated tumors in the hepatic parenchyma. However, the biophysical and thermal characteristics of these implantable cryoprobes have not been studied. This article discusses the biophysical and thermal characteristics of recently developed high-efficiency, implantable needle cryoprobes that can be used laparoscopically. The cryolesion was formed along the whole length of the cryoprobe implanted into hepatic tissue. It was cylindrical in shape and extended 8 mm beyond the tip of the cryoprobe after 20 minutes of freezing. During this period of freezing, the volume of the cryolesion increased in a near constant manner, but the diameter increased in a logarithmic fashion. In addition, single-cycle freezing produced a larger cryolesion than a dual freeze cycle interrupted by a 5-minute thaw. Further, increasing the length of cryoprobe implantation increased the volume of the cryolesion, although the diameter was smaller. The rate of cooling at the tip of the cryoprobe was also faster with partial implantation of the cryoprobe than with complete implantation. The cooling rate varied vertically along the length of the cryoprobe, as well as horizontally from the cryoprobe.

Journal Article↗
PubMed2004

Biophysical characterization of ERp29. Evidence for a key structural role of cysteine 125.

ERp29 is a major resident of the endoplasmic reticulum (ER) that seemingly plays an important role in most animal cells. Although a protein-folding association is widely supported, ERp29's specific molecular function remains unknown. A chaperone activity was postulated from evidence that ERp29 forms multimers like the classical ER chaperones, but conflicting results have emerged from our recent studies. Here a biophysical approach was used to clarify this issue and also reveal a key structural role for ERp29's characteristic cysteine, Cys-125. Applying hydrodynamic parameters derived from sedimentation and dynamic light-scattering analyses, a model of ERp29's quaternary structure was assembled from existing tertiary substructures. Comparison with Windbeutel, an ERp29-like protein from fruit fly with specialized chaperone activity, revealed similar tri-lobar gross structures but some finer differences consistent with functional divergence. Solubility and hydrophobic probe assays revealed moderate surface hydrophobicity, which was reduced in mutant ERp29 in which serine replaced Cys-125. This mutant was also relatively labile to proteolytic degradation, providing two reasons for the strict conservation of Cys-125. No multimerization was observed with untagged ERp29, which existed as tight homodimers (K(d) < 50 nm), whereas His-tagged ERp29 artifactually formed 670-kDa oligomers. These findings distinguish ERp29 biophysically from its peers in the ER including Windbeutel, endorsing our postulate that ERp29 adds a distinct type of folding activity to the ER machinery. By invoking novel functional associations for Cys-125 and the adjoining linker, new clues about how ERp29 might work have also arisen.

Animals↗
PubMed2005

Biophysical modeling of tonic cortical electrical activity in attention deficit hyperactivity disorder.

Psychophysiological theories characterize Attention Deficit Hyperactivity Disorder (ADHD) in terms of cortical hypoarousal and a lack of inhibition of irrelevant sensory input, drawing on evidence of abnormal electroencephalographic (EEG) delta-theta activity. To investigate the mechanisms underlying this disorder a biophysical model of the cortex was used to fit and replicate the EEGs from 54 ADHD adolescents and their control subjects. The EEG abnormalities in ADHD were accounted for by the model's neurophysiological parameters as follows: (i) dendritic response times were increased, (ii) intrathalamic activity involving the thalamic reticular nucleus (TRN) was increased, consistent with enhanced delta-theta activity, and (iii) intracortical activity was increased, consistent with slow wave (<1 Hz) abnormalities. The longer dendritic response time is consistent with the increase in the activity of inhibitory cells types, particularly in the TRN, and therefore reduced arousal. The increase in intracortical activity may also reflect an increase in background activity or cortical noise within neocortical circuits. In terms of neurochemistry, these findings may be accounted for by disturbances in the cholinergic and/or noradrenergic systems. To the knowledge of the authors, this is the first study to use a detailed biophysical model of the brain to elucidate the neurophysiological mechanisms underlying tonic abnormalities in ADHD.

Acetylcholine↗
PubMed2000

Biophysical and molecular mechanisms underlying the modulation of heteromeric Kir4.1-Kir5.1 channels by CO2 and pH.

CO2 chemoreception may be related to modulation of inward rectifier K+ channels (Kir channels) in brainstem neurons. Kir4.1 is expressed predominantly in the brainstem and inhibited during hypercapnia. Although the homomeric Kir4.1 only responds to severe intracellular acidification, coexpression of Kir4.1 with Kir5.1 greatly enhances channel sensitivities to CO2 and pH. To understand the biophysical and molecular mechanisms underlying the modulation of these currents by CO2 and pH, heteromeric Kir4. 1-Kir5.1 were studied in inside-out patches. These Kir4.1-Kir5.1 currents showed a single channel conductance of 59 pS with open-state probability (P(open)) approximately 0.4 at pH 7.4. Channel activity reached the maximum at pH 8.5 and was completely suppressed at pH 6.5 with pKa 7.45. The effect of low pH on these currents was due to selective suppression of P(open) without evident effects on single channel conductance, leading to a decrease in the channel mean open time and an increase in the mean closed time. At pH 8.5, single-channel currents showed two sublevels of conductance at approximately 1/4 and 3/4 of the maximal openings. None of them was affected by lowering pH. The Kir4.1-Kir5.1 currents were modulated by phosphatidylinositol-4,5-bisphosphate (PIP2) that enhanced baseline P(open) and reduced channel sensitivity to intracellular protons. In the presence of 10 microM PIP2, the Kir4.1-Kir5.1 showed a pKa value of 7.22. The effect of PIP2, however, was not seen in homomeric Kir4.1 currents. The CO2/pH sensitivities were related to a lysine residue in the NH2 terminus of Kir4.1. Mutation of this residue (K67M, K67Q) completely eliminated the CO2 sensitivity of both homomeric Kir4.1 and heteromeric Kir4.1-Kir5.1. In excised patches, interestingly, the Kir4.1-Kir5.1 carrying K67M mutation remained sensitive to low pHi. Such pH sensitivity, however, disappeared in the presence of PIP2. The effect of PIP2 on shifting the titration curve of wild-type and mutant channels was totally abolished when Arg178 in Kir5.1 was mutated. Thus, these studies demonstrate a heteromeric Kir channel that can be modulated by both acidic and alkaline pH, show the modulation of pH sensitivity of Kir channels by PIP2, and provide information of the biophysical and molecular mechanisms underlying the Kir modulation by intracellular protons.

Animals↗
PubMed2000

Plasma total cholesterol concentrations do not predict cerebrospinal fluid neurotransmitter metabolites: implications for the biophysical role of highly unsaturated fatty acids.

Low concentrations of a metabolite of serotonin found in cerebrospinal fluid (CSF), 5-hydroxyindolacetic acid (5-HIAA), are strongly associated with suicidal and violent behaviors. Although lowering of plasma total cholesterol has been suggested to increase mortality from suicide and violence by decreasing concentrations of CSF 5-HIAA via changes in membrane biophysical properties, highly unsaturated fatty acids may play a more important role. Violent and nonviolent comparison groups, early- and late-onset alcoholics, and healthy comparison subjects were studied to control for alcohol use and predisposition to violence. Fasting plasma total cholesterol and CSF were assayed under stringently controlled conditions. When all groups were combined (n = 234), plasma cholesterol concentrations had a weak positive correlation with CSF 5-HIAA (r = 0.18, P < 0.01). However, age correlated with both plasma total cholesterol and CSF 5-HIAA concentrations. When age was included in multiple regression models, the correlation between cholesterol and CSF 5-HIAA concentrations was not significant. Cholesterol correlated weakly with CSF 5-HIAA concentrations only in late-onset alcoholics after age was controlled for, but the relation was not significant after correction for multiple testing. CSF homovanillic acid did not correlate with plasma total cholesterol in any group. Plasma total cholesterol had no apparent relation to CSF neurotransmitter metabolites in any group of subjects. Highly unsaturated essential fatty acids, which are also critical determinants of membrane biophysical properties and may be linked to brain serotonin concentrations, should also be considered in studies examining the effect of lowering fat intake on the incidence of suicide and violence.

Adult↗
PubMed2002

Epitope affinity chromatography and biophysical studies of monoclonal antibodies and recombinant antibody fragments.

Peptide epitope affinity chromatography is a powerful technique for the purification of antibodies. This study aims to demonstrate the versatility of the technique and to show how biophysical techniques such as circular dichroism (CD) and fluorescence quenching (FQ) can aid the rational design of affinity ligands and characterization of antibody-based reagents. The performance of a number of peptide ligands for the purification of a range of different antibodies and recombinant fragments is investigated by automated fast-protein liquid chromatography. Purified products are analyzed for purity by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. They are then radiolabelled and the immunoreactivity is determined. Ligands are analyzed for secondary structural characteristics by CD and for binding affinity by FQ. Finally, a study is performed to investigate the thermal stability of a recombinant antibody fragment by CD analysis. It is found that simple ligand modifications such as the introduction of a C-terminal cysteine residue can improve purification performance. The FQ studies show that the modified peptide has a higher affinity for antibody. The CD analysis shows that it has a tendency to dimerize because of the formation of disulfide bonds. The versatility of epitope affinity is demonstrated through the purification of a recombinant diabody (dbFv) and by the use of a separate peptide matrix for the purification of an unrelated antibody. All studies result in antibody preparations of high purity and immunoreactivity. The CD analysis of the dbFv shows that it is denatured at 37 degrees C and is therefore unsuitable as a targeting reagent for use in humans in its present form. It is concluded that epitope affinity chromatography coupled with biophysical analyses plays an important role in the production and characterization of antibody-based reagents for targeted diagnosis and therapy of human diseases.

Amino Acid Sequence↗
PubMed1987

Antepartum fetal surveillance: the biophysical profile.

In summary, it appears, based on a cumulative experience of more than 15,000 patients from several centers, that fetal biophysical profile scoring holds promise as an improved method of fetal risk detection. Antepartum detection, classification, determination of severity, and ultimately, treatment of the fetus at risk for death and damage in utero form the basis of modern perinatal medicine. It remains to be determined whether addition of further variables or refinement of existing variables will improve accuracy still further. The assessment of multiple biophysical variables and responses to intrinsic and extrinsic stimuli is helpful in differentiating a normal sleeping fetus from an asphyxiated one.

Female↗
PubMed1982

Biophysical properties of resuscitation fluids.

The preliminary results of this study indicate that the biophysical characteristics of stroma-free hemoglobin solution (SFH) make it an extremely suitable blood substitute. At the concentration that is currently being considered as an infusing solution (70 g/L), it is a Newtonian fluid having a viscosity very similar to that of plasma. At this concentration, SFH also has very favorable hemodilution properties, as well as potential oxygen transport ability, which most expanders lack. There seems to be little interaction between the plasma proteins and SFH, as indicated from viscosity measurements. The osmotic behavior of SFH indicates that it approaches an ideal polymer-solvent system as illustrated by the small value of the second virial coefficient, especially when compared to other plasma substitutes. In mixtures with whole blood at a series of hematocrits, SFH seems to be hyperosmotic. This biophysical property could certainly have significance in patients with severe shock. SFH maintains the integrity of whole blood and does not initiate erythrocyte aggregation. The investigations of the erythrocyte sedimentation rate (ESR) in this study with SFH indicate the potential usefulness of SFH in maintaining stability of these systems, particularly during the treatment of shock. The transport properties of the red cell membrane are apparently not effectively altered by the presence of SFH. This has been illustrated in the hemolytic malonamide kinetic and osmotic fragility studies. Although the results are preliminary, it should be stressed that SFH may offer protection against hemolysis when used as a transfusion solution.

Biological Transport↗
PubMed2003

Changes in biochemical and biophysical surfactant properties with cardiopulmonary bypass in children.

OBJECTIVE: The aim of the present study was to characterize pulmonary surfactant properties in children undergoing cardiovascular surgery with cardiopulmonary bypass. DESIGN: Prospective clinical trial. SETTING: University hospital pediatric intensive care unit. PATIENTS: Fifty pediatric patients with congenital cardiac defects undergoing cardiovascular surgery with (n = 35) and without (n = 15) cardiopulmonary bypass procedure. INTERVENTIONS: Tracheal aspirates were collected by saline lavage during routine suctioning before (baseline) and after cardiopulmonary bypass, as well as 4, 8, and 24 hrs after admission to the pediatric intensive care unit. MEASUREMENTS AND MAIN RESULTS: Total protein and phospholipid concentrations were assessed in native tracheal aspirates, in large surfactant aggregates, and in small surfactant aggregates. Phospholipid profiles and phosphatidylcholine fatty acids; surfactant apoproteins SP-A, SP-B, and SP-C (enzyme-linked immunosorbent assay); and surface activity (Pulsating Bubble Surfactometer) were all analyzed in large surfactant aggregates. With cardiopulmonary bypass, an initial increase in total protein content was followed by an increase in phospholipid concentration in tracheal aspirates. Large surfactant aggregates decreased 4 hrs after cardiopulmonary bypass (4 hrs, 22.6 +/- 5.6%; mean +/- SEM; p<.01 compared with baseline, 55.4 +/- 9.2%) but recovered within 24 hrs. The phospholipid-protein ratio of large surfactant aggregates 24 hrs after cardiopulmonary bypass (1.2 +/- 0.2; p<.01) was significantly decreased compared with baseline (2.9 +/- 0.6). The relative amount of phosphatidylglycerol content in the large surfactant aggregates-fraction dropped linearly over time but other phospholipids remained mainly unchanged. Phosphatidylcholine fatty acid profiles remained unaffected by cardiopulmonary bypass. The relative content of SP-B and SP-C in large surfactant aggregates increased approximately three-fold compared with baseline. Altogether, our findings with recovered large surfactant aggregate/small surfactant aggregate ratios and increased phospholipid in tracheal aspirates after 24 hrs represent an approximately ten-fold increase in large surfactant aggregate-associated SP-B and SP-C compared with baseline. Only minor changes were detected in biophysical properties of large surfactant aggregates throughout the observation period. CONCLUSIONS: Cardiopulmonary bypass procedure in children induces profound changes in the surfactant system involving both phospholipid and protein components; biophysical function may have been maintained by compensatory increase in SP-B and SP-C.

Cardiopulmonary Bypass↗
PubMed1988

Does the onset of spontaneous labor at term influence fetal biophysical test parameters?

Recent data suggest that fetal breathing movement incidence declines while fetal heart rate (FHR) and body movement incidence do not change within 72 hours of spontaneous term labor. We conducted a retrospective study to determine whether the length of time from testing to spontaneous labor onset could influence these biophysical test parameters. Eighty-one normal term fetuses underwent 60-minute tests 1-40 days before the onset of spontaneous labor: 41 were tested within 7 days of labor (19 within 3 days and 22 within 4-7 days) and 40 were tested more than 7 days before labor. We simultaneously acquired and analyzed FHR baseline, frequency of accelerations between ten to 14 beats per minute and more than 15 beats per minute in amplitude, percent of time spent in breathing and moving, and fetal breath rate. These biophysical parameters were not significantly different between the groups, implying that they may continue to provide clinically useful information in the prelabor period.

Female↗
PubMed2005

Doppler, cardiotocography, and biophysical profile changes in growth-restricted fetuses.

OBJECTIVE: To assess from diagnosis to delivery the Doppler studies of the umbilical artery, middle cerebral artery, umbilical vein, ductus venosus, and amniotic fluid index of fetuses with idiopathic growth restriction. METHODS: A total of 145 singleton growth-restricted fetuses with abnormal umbilical artery pulsatility indexes were studied. Cesarean delivery was performed because of abnormal biophysical profile or nonreassuring fetal heart rate pattern. RESULTS: There were 4 fetal and 50 neonatal deaths. Two growth-restricted groups were identified: Group A (n = 44) included fetuses in whom all measures became abnormal preceding an abnormal biophysical profile or nonreassuring nonstress test. Group B (n = 101) included fetuses in whom 1 or more measures were normal at the time of cesarean delivery. There was no statistically significant difference in perinatal morbidity and mortality between the 2 groups. Neonatal death was increased in fetuses with umbilical artery reversed flow (odds ratio 2.34, 95% confidence interval 1.16-4.73; P < .05) and ductus venosus reversed flow (odds ratio 4.18, 95% confidence interval 2.01-8.69; P < .05). A significant correlation was also found between low birth weight and adverse perinatal outcome. CONCLUSION: In fetuses with idiopathic growth restriction, 1) low birth weight, 2) umbilical artery reversed flow, and 3) ductus venosus absent or reversed flow are associated with an increased perinatal morbidity and mortality.

Analysis of Variance↗