摘要:

Cerebral blood flow measurement has been an important investigative tool in newborns at risk for perinatal brain damage. The validity of Doppler cerebral blood flow velocity measurements depends on a constant vessel diameter. We have validated Doppler against the electromagnetic flowmeter (EM) using a modified common carotid artery model in the 1-d-old piglet. Two sets of continuous and simultaneous recordings were performed:1) the Doppler and EM probe on the same common carotid artery (extracerebral branches were ligated), and2) the EM probe on the common carotid artery and the Doppler probe recording from an intracerebral artery through an artificial fontanel. Arterial partial pressure of carbon dioxide (PaCO2) was manipulated (2.8–7.4 kPa), as was arterial blood pressure (3.7–9.3 kPa). Simultaneous EM flow and estimated Doppler flow were compared. Ninety-three recordings were obtained with both transducers on the modified carotid artery, and 49 were obtained with the Doppler insonicating an intracerebral artery. A multiple regression model was used for statistical analysis. The correlation between EM and both sets of Doppler measurements for individual animals was >0.95 and was unaffected by changes in arterial blood pressure or PaCO2. Thus, the common carotid and the intracerebral artery investigated did not change their diameter significantly in response to PaCO2or arterial blood pressure. The relationships between EM and Doppler in the individual animal were all linear but revealed great variability in the slopes due to the unknown vessel diameter and angle of insonication. We conclude that relative changes of cerebral blood flow velocity in the modified common carotid artery and intracerebral arteries show the same changes as common carotid artery blood flow (determined by an EM) in the healthy 1-d-old piglet.

ISSN:0031-3998    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Hereditary ataxias are a heterogeneous group of progressive neurodegenerative disorders characterized by symptoms and signs originating mainly in the CNS. A new representative of this disease group is infantile onset spinocerebellar ataxia, an autosomal recessively inherited syndrome so far reported only in the genetically isolated Finnish population. The etiology of hereditary ataxias still remains unknown, but the gene loci behind many of them have been mapped to different chromosomal regions. We have carried out linkage analyses with markers on the regions of the previously identified ataxia loci to determine whether the infantile onset spinocerebellar ataxia syndrome represents the same allelic disease as any of the previously identified hereditary ataxias. Here we report that the infantile onset spinocerebellar ataxia syndrome does not segregate with any of the markers closely linked to the other hereditary ataxias. Consequently, it represents a genetically distinct disease, the gene locus of which still has to be identified.

ISSN:0031-3998    

出版商:OVID    

年代:1994

数据来源: OVID

ISSN:0031-3998    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

To examine uridine diphosphate hexose (UDPhexose) content of cells that have more complete metabolic patterns than erythrocytes, which have been commonly used in the study of galactosemia, the concentrations of uridine diphosphate galactose (UDPgalactose) and uridine diphosphate glucose (UDPglucose) were determined in white blood cells (WBC) and fibroblasts cultured from skin biopsies. Leukocyte UDPgalactose and UDPglucose values were determined in 60 normal individuals, 14 classic gamactosemics, and 18 patients with other metabolic diseases on protein-restricted and low-lactose diets. There was no difference in the average concentration of these compounds between any of these groups. There was no relationship between age and WBC UDPhexose content or correlation of WBC and erythrocyte UDPhexose levels in the same blood specimens. WBC from galactosemic individuals differ from their red blood cells because the former do not show the low average UDPgalactose levels and abnormal UDPglucose to UDPgalactose ratio previously reported for erythrocytes from galactose-1-phosphate uridyltransferase-deficient individuals. Fibroblast cell lines from 10 normal and 10 galactosemic individuals, cultured and grown to confluence in glucose medium, also showed no difference in nucleotide sugar concentrations. Thus far, of the cell types easily available, red blood cells appear to be unique in showing an abnormality in nucleotide sugar metabolism. The fact that galactosemic fibroblasts demonstrate no abnormality in the concentration of these compounds suggests that the defective galactosylation that has been observed in galactosemic fibroblasts is not due to unavailability of UDPgalactose.

ISSN:0031-3998    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Superoxide anion (O2-) production was investigated in whole blood of mothers in the peripartal period and in neonates. Blood samples from 14 mothers undergoing vaginal delivery (VD) were tested at the beginning of labor, during labor, after delivery, and 4 d after delivery. Nine mothers undergoing elective cesarean section (ECS) were tested before anesthesia, after extraction of the fetus, and 4 d later. Seventy-two healthy, full-term newborn infants were examined at birth and on the fourth day of life. Red cell glutathione peroxidase, catalase, glutathione reductase, and superoxide dismutase activities were also measured at birth and on the fourth day of life in 26 of the 72 neonates. Higher O2-levels were detected in mothers undergoing VD compared with ECS (p< 0.05). A significant decrease was detected in zymosan-stimulated O2-production between cord and fourth-day blood samples in both VD- and ECS-delivered infants (p< 0.01). Zymosan-stimulated samples showed higher values after VD than ECS, both in cord blood (p< 0.004) and on the fourth day of life (p< 0.006). A positive correlation was found between O2-release in zymosan-stimulated cord blood and that found in the mothers at the beginning of labor (r0.654;p< 0.01), during labor (r= 0.721;p= 0.008), and after delivery (r= 0.832;p= 0.0008). A positive correlation was also found between O2-release and glutathione peroxidase on the fourth day (r= 0.709,p= 0.014). The results of the present investigation demonstrate the role of peripartal events in modulating free radical release by polymorphonuclear leukocytes during the perinatal period.

ISSN:0031-3998    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

To investigate further the susceptibility to infection of newborn infants, particularly those born prematurely, we have used a “whole blood” flow cytometric assay to compare the respiratory burst activity in recombinant human granulocyte-macrophage colony stimulating factor “primed” neutrophils obtained from healthy adults, term infants, and preterm newborn infants. The use of whole blood avoids prior cell separation procedures that may cause artifactual activation or priming. In healthy adults (p= 21), the bacterial cell wall peptide N-formyl-methionyl-leucyl-phenylalanine induced little neutrophil respiratory burst activity, suggesting that the circulating cell is relatively quiescent. Prior exposure to recombinant human granulocyte-macrophage colony stimulating factor augmented the median N-formyl-methionyl-leucyl-phenylalanine response by 425%. In cord blood from full-term neonates (p= 9), recombinant human granulocyte-macrophage colony stimulating factor produced less enhancement of the N-formyl-methionyl-leucyl-phenylalanine response (345%), but the absolute level of respiratory burst activity was at least as great as in adults, suggesting that the neutrophils are fully functional and partially primed after delivery. In preterm infants receiving intensive care (p= 10), the degree of priming was similar to that in neutrophils from term infants (344%), although the absolute level of respiratory burst activity was reduced (p= 0.0003). In response to stimulation with phorbol ester, 73.5% (18–99%) (median and range) of neutrophils obtained from adults and 77.6% (50–92%) from term babies exhibit respiratory burst activity detectable in the whole blood assay. However, in neutrophils obtained from preterm infants, there was a significant reduction in the phorbol ester-induced respiratory burst, with only 32.9% (21–61%) of cells responding (p= 0.0129).

ISSN:0031-3998    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Uponin vitrostimulation with 10 μM ionophore A 23187 for 5 min at 37°C, the generation of leukotriene (LT) C4in polymorphonuclear leukocytes (PMNL) from nine untreated cystinotic children was significantly increased compared with that in eight control children (p< 0.01) and 25 normal adults (p< 0.001) (417.4 ± 70.0versus177.0 ± 30.9 and 164.9 ± 19.5 pmol/1 x 107cells, respectively). Concomitantly with the increased generation of LTC4, LTB4production in PMNL from untreated cystinotic children was decreased compared with controls, whereas the total amount of LTA4derivatives was similar in the three groups. The increase in LTC4production was not related to the number of eosinophils present in the PMNL preparations from cystinotic children, which was similar to that of control subjects. PMNL from cystinotic children treated with cysteamine, an aminothiol compound that decreases the intracellular cystine content, generated smaller amounts of LTC4upon ionophore A 23187 stimulation than PMNL from untreated cystinotic children. In addition, abrogation of the cysteamine treatment for 3 or 4 d led to an increase in LTC4production. These findings suggest that the metabolic abnormalities taking place in infantile cystinosis may favor the biosynthesis of LTC4from PMNL.

ISSN:0031-3998    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

The binding patterns of gliadin and selected lectins to jejunal biopsy specimens obtained from children with total villous atrophy during active celiac disease (CD; 19 patients) and in remission (16 patients) were examined by light microscopy. Three categories of carbohydrate-specific lectins were chosen for the study: those recognizing mannose/glucose residues, those recognizing N-acetyl-glucosamine/glucose (glcNAc/glc) residues, and those recognizing N-acetylgalactosamine/galactose (galNAc/gal) residues. The galNAc/gal lectins, with the exception of phaseolus vulgaris agglutinin variants, presented a typical staining of the luminal surface of the jejunal mucosa obtained from CD patients. However, these lectins displayed no reactivity to jejunal sections of CD patients in remission or control biopsies that included healthy children (25 children) and patients suffering from cow milk protein allergy (10 children). The glcNAc/glc lectin showed a strong preferential recognition of CD jejunal tissue but also bound with less intensity to specimens from patients with cow milk allergies and healthy children. Unlike other galNAc/gal lectins, phaseolus vulgaris agglutinin variants were indistinguishable in their binding patterns to the mucosa of control groups and CD patients in remission and failed to react to CD biopsies. The mannose/glc lectins were not distinctive in their binding patterns. In all cases, lectin binding was specifically inhibited by the lectins' competitive saccharides. Atypical of lectin binding patterns, gliadin reactivity was restricted to intracellular areas of enterocytes and was unique to active CD mucosa. The distinctive binding patterns of lectins and gliadin provide a diagnostic tool to distinguish patients with active CD from those in remission or patients with other intestinal disorders. These findings raise interesting questions about the role of gliadin and lectins in CD. It is speculated that the presence of new luminal sites may act to manifest lectin susceptibility and exacerbate CD pathology.

ISSN:0031-3998    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Delayed gastric emptying is a common problem in preterm infants. The factors underlying this gastroparesis remain unsettled but may involve immaturity of smooth muscle contraction. The present study was designed to test this hypothesis. Muscle strips from the gastric fundus of fetal and adult guinea pigs were studiedin vitrofor their contractile response to receptor activation (acetylcholine and bethanechol) and membrane depolarization (potassium chloride). The dose-response curves were analyzed for differences in active force development (kg/cm2). The role of extracellular calcium (Ca2+) in the contractile responses was determined by contracting the tissues in a zero-Ca2+physiologic saline solution and in the presence of nifedipine, a voltage-dependent Ca2+channel blocker. The results demonstrate the following:1) tissues from adult animals developed significantly more active force when tested with acetylcholine, bethanechol, and potassium chloride;2) tissues from the fetal animals were relatively unresponsive to contraction with potassium chloride compared with the adult; and3) both nifedipine and incubation in a zero-Ca2+physiologic saline solution had a significantly greater inhibitory effect on the contractions of adult than fetal muscle strips. Our data indicate that smooth muscle in the gastric fundus develops increasing force with maturation. The increased contractility in the adult fundus appears to be due to an increased involvement of extracellular calcium influx, in part through voltage-dependent Ca2+channels.

ISSN:0031-3998    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

We studied the activation pattern of clotting, fibrinolysis, and kinin-kallikrein during the first 5 d of life in 10 preterm infants with signs of severe idiopathic respiratory distress syndrome (IRDS) after birth (IRDS group) and in 12 healthy preterm infants (reference group). We found systemic activation of clotting, fibrinolysis, and kinin-kallikrein in the IRDS infants within 12 to 24 h of birth, represented by increased median thrombin-antithrombin III complex formation (90 ng/mLversus10 ng/mL in the reference group,p< 0.05), increased mean tissue-type plasminogen activator plasma concentrations (11.8 ng/mLversus3.5 ng/mL in the reference group,p< 0.05), and increased mean plasma kallikrein activity (182.6%versus162.0% of maximal activated human plasma in the reference group,p< 0.05), respectively. Clotting activation was accompanied by a significant decrease of the platelet count. Clotting and fibrinolytic activity decreased in the IRDS group during the first 2 to 3 d of life. Kinin-kallikrein activation was accompanied by decreased plasma kallikrein inhibitor activity values and did not change throughout the study period. Plasma factor XII activity was not significantly increased in the IRDS infants during the first 2 d of life but did significantly increase thereafter. The cause of simultaneous activation of clotting, fibrinolysis, and kinin-kallikrein in our IRDS infants has not yet been clarified. However, this activation process may contribute to lung injury such as that described in the adult respiratory distress syndrome.

ISSN:0031-3998    

出版商:OVID    

年代:1994

数据来源: OVID