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Study of the oligosaccharide units from mucus glycoproteins of meconium from normal infants and from cases of cystic fibrosis with meconium ileus.

1. The mucus glycoproteins in meconium from normal infants and from infants having cystic fibrosis with meconium ileus have been studied. 2. Whereas normal meconium contained about 50% protein-bound carbohydrate, the meconium from cystic fibrosis contained only about 10%. 3. Glycopolypeptides were prepared from the mucus of glycoproteins. The oligosaccharide units from this material were released and fractionated. The fractions ranged widely in size and composition. 4. The fractions from cystic fibrosis specimens had a significantly higher content of fucose than those from normal specimens.

Carbohydrate Metabolism

Significance of meconium during labor.

Continuous fetal heart rate (FHR) monitoring and routine fetal scalp blood sampling was utilized in the evaluations of 366 fetuses during labor. One hundred and six patients had meconium in the amniotic fluid at some time during labor. A total of 26,110 uterine contractions were monitored during these 366 labors. The incidence of FHR patterns as a percentage of uterine contractions was calculated for the meconium and nonmeconium groups. Although there was a 3 1/2-fold increase in the incidence of low five-minute Apgar scores (less than 7) in the meconium group, signs of fetal distress were, with rare esception, not significantly different from those in the nonmeconium group. The presence of meconium in the amniotic fluid without signs of fetal asphyxia (late decelerations and acidosis) is not a sign of fetal distress and need not be an indication for active intervention. The combination of fetal asphyxia and meconium staining of the amniotic fluid, however, does enhance the potential for meconium aspiration and a poor neonatal outcome. Universal fetal heart rate monitoring and appropriate fetal acid-base evaluation is recommended for following patients with meconium in the amniotic fluid during labor.

Acid-Base Equilibrium

Screening for cystic fibrosis in the newborn by meconium analysis.

During a 4-year routine screening programme for cystic fibrosis (CF) 15 464 specimens were examined for raised meconium albumin levels by a test strip method and by electroimmunoassay. The incidence of false-positive results was about 5 per 1000 specimens in either test. This could be reduced by 90% by determining the ratio of albumin : alpha-1-trypsin inhibitor (a ratio below 2.0 being considered as a negative result), and it could be reduced to zero by determining the ratio in subsequent faecal specimens. Three of 12 meconium specimens from infants with proved CF gave false-negative results in all 3 tests. The other 9 specimens had greater than 100 mg albumin/g dry weight and albumin: alpha-1-trypsin inhibitor ratios of greater than 3.0; in subsequent faecal specimens the ratios were over 4.0. 176 meconium specimens from elsewhere in the UK were examined and these included 23 from infants who were subsequently proved to have CF. Six of these 23 CF specimens gave false-negative results, the other 17 being strongly positive. The origins of meconium serum protein suggest that infants with CF in whom meconium gives false-negative results have normal pancreatic functions at birth. The specificity of current meconium tests therefore cannot be improved as they depend on pancreatic dysfunction.

Albumins

Studies in meconium. An approach to screening tests to detect cystic fibrosis.

Screening for cystic fibrosis (CF) in newborns is desirable, and efforts should continue in establishing a system of easily available, reliable, simple, and inexpensive tests. In addition to the Boehringer-Mannheim (BM) test for the detection of albumin, we propose the assay for lactase and beta-D-fucosidase in meconium. These latter two enzymes are present in the meconium of babies with CF and absent in meconium of most healthy babies. In a mass screening program for CF involving 20,182 specimens of meconium using only the BM strip, we found 46 positive results. Twenty-nine specimens came from infants with CF, six of whom had meconium ileus. Seventeen specimens yielded false-positive results by the BM test. Eleven of these would have been excluded by the addition of the lactase and beta-D-fucoside assay, thus reducing the false-positive test results by nearly 61%. In a comparative study of the three methods, the lactase and beta-D-fucosidase yielded 1.2% false-positives when examined independently. Performance of these two assays may allow greater specificity in diagnosis when used in addition to the BM test.

Albumins

Automated immunoprecipitation of meconium albumin for cystic fibrosis screening in the newborn.

Cystic fibrosis is the most frequent substantially lethal inherited disease in the United States. Newborn screening for cystic fibrosis has been suggested because early diagnosis permits genetic counselling of parents and improved treatment and prognosis for cystic fibrosis patients. The fact that cystic fibrosis newborns have abnormally high meconium albumin seems to offer the best screening approach. Because we have had equivocal and false positive results with meconium albumin test strips, we have developed a nephelometric automated immunoprecipitation method for the quantitative and specific analysis of meconium albumin. On a total of 3895 meconiums so far examined, eleven albumin elevations of undetermined origin have been detected. Nine of these were associated with prematurity. There have been, so far, no detected true positives and no known false negatives. The normal range for meconium albumin is in agreement with previously published ranges determined using manual immunochemical methods. This method is rapid and economic. The question of sensitivity, specificity and predictive value of this and other detection methods is discussed.

Albumins

Conjugated and unconjugated bilirubins in humans and rhesus monkeys. Structural identity of bilirubins from biles and meconiums of newborn humans and rhesus monkeys.

1. Bilirubin-IXalpha monoglucuronide was the predominant bilirubin in biles and meconiums of newborn humans and rhesus monkeys. Rhesus-monkey baby biles contained slightly more diglucuronide than did human baby biles. 2. Bilrubin-IXalpha glucoside, bilirubin-IXalpha xyloside and bilirubin-IXbeta were also constituents of human and rhesus-monkey baby biles and meconiums. Bilirubin-IXalpha glucuronide glucoside was present in human and rhesus-monkey baby biles but not in meconiums. The identity of the bilirubins was confirmed by u.v.-visible and mass spectroscopy of the azodipyrroles obtained by treating the bilirubins with diazotized ethyl anthranilate. The resulting azodipyrroles were identical with the corresponding azodipyrroles obtained from human adult biles and also from reduced isomers of biliverdin. 3. Bilirubin-IXbeta was present in much higher proportions in the extracts of meconiums than in the extracts of biles from the same babies. 4. Oxidation of bilirubins to biliverdins occurs in utero to a small but undetermined extent. The resulting green pigments were present in meconiums collected from the lower small and large intestines of newborn babies and rhesus monkeys. 5. Butanol extracted most of the bilirubins present in biles. This modified method proved to be quick and easy. Little hydrolysis of bilirubins took place during extraction or separation by t.l.c.

Adult

Neonatal meconium obstruction in the ileum without mucoviscidosis.

Two newborns with intestinal obstruction of the terminal ileum without mucoviscidosis were cured by Gastrografin enema. A further case of a premature infant showed, at autopsy, a large intestine containing normal meconium, but an ileum which was plugged with tenacious meconium containing PAS-positive and alcian blue-negative mucus. Our 3 cases were similar to cases of "meconium disease" reported by Rickham and of "meconium plug in the small intestine" reported by Emery. The primary cause of this disease lies in the large amount of PAS-positive mucus secreted from goblet cells of the ileal mucosa and the hypertrophy of lymph nodules in the ileal submucosa.

Contrast Media

In utero distal pulmonary meconium aspiration.

We have recently had eight cases of severe meconium aspiration syndrome which occurred despite clearing of the posterior pharynx of meconium after delivery of the head but before delivery of the body. Seven of the eight cases had documented fetal distress before delivery. Two stillborns with meconium aspiration are presented and illustrate that electronic fetal monitoring and aggressive obstetric intervention should be coupled with the suctioning technic to prevent significant mortality and morbidity associated with meconium-stained deliveries.

Female

Unconjugated serum oestriol levels in mother and baby with meconium staining of the amniotic fluid.

To examine the effect on oestrogen metabolism of the stimulus which causes the passage of meconium, we measured maternal venous and cord artery and vein serum unconjugated oestriol levels in 46 patients with meconium staining of the amniotic fluid and 19 controls. Mean cord vein oestriol levels were significantly lower than in controls in the presence of meconium stained amniotic fluid and no fetal acidosis (cord artery buffer base of 36.2 meq/l or more) (P less than 0.02). The same tendency was seen with acidotic infants (P less than 0.05). There is thus evidence of a change in oestrogen metabolism associated with meconium staining of the amniotic fluid.

Acid-Base Equilibrium

Studies in meconium in cystic fibrosis: the activities of alpha-D-mannosidase, beta-glucuronidase, beta-D-fucosidase, acid and alkaline phosphatase.

The specific activities of alpha-D-mannosidase, beta-glucuronidase, beta-D-fucosidase, acid and alkaline phosphatase were studied in meconium from infants with cystic fibrosis (CF) and control subjects. The study revealed significant variations in the specific activity of the enzymes except for acid phosphatase. The variations were not uniform. The activities of alpha-D-mannosidase, beta-glucuronidase and alkaline phosphatase were markedly decreased (p less than 0.001, p less than 0.002, p less than 0.001, respectively), while the activity of beta-D-fucosidase was significantly increased (p less than 0.001) in meconium from the infants with CF. It is suggested that the decreased activity of alpha-D-mannosidase and beta-glucuronidase might contribute to the accumulation of the abnormal substances in CF meconium. The highly increased activity of beta-D-fucosidase raises the possibility of an additional or alternative method for screening newborns for CF using meconium as the test material.

Acid Phosphatase

Bile pigments in humans and in nonhuman primates during the perinatal period: composition of meconium and gallbladder bile of newborns and adults.

Meconium of human infants and rhesus monkey infants (Macaca mulatta) contained only about 0.10 of the amount of bilirubin in gallbladder bile of the same individuals. Ninety-nine percent of the bilirubin in adult bile was conjugated. The proportion of conjugated bilirubin in infant bile and meconium was only slightly lower. Adult bile contained more bilirubin disconjugates than monoconjugates, whereas only 20% of the bilirubin in infant bile and meconium was in the form if disconjugates. The predominant azopigment in adult bile was azopigment delta (a glucuronide). Infant bile contained less azopigment delta, more azopigment alpha (azodipyrrole), and a so far unidentified conjugated azopigment (azopigment beta). Azopigment beta was also found in meconium but adult gallbladder bile contained only trace amounts of this pigment.

Adult

Assisted ventilation in infants with meconium aspiration syndrome.

In a retrospective analysis of infants born with meconium staining over an 18-month period at Cook County Hospital, 32 infants met two of the three criteria for the diagnosis of meconium aspiration syndrome: (1) history of meconium in the oropharynx or trachea; (2) clinical evidence of respiratory distress; and (3) x-ray evidence of aspiration pneumonia. Seventeen infants developed respiratory failure; nine of these infants died. One infant without respiratory failure died of sepsis. Analysis of sequential arterial blood pH and gas tension showed that nonsurviving infants had persistently high PCO2 and A-a gradient in spite of initiation of assisted ventilation. These changes seem to be related to severe right-to-left shunting and ventilation perfusion abnormalities. The data further suggest that asphyxia and acidosis occur well before the infant is born and that intrapartum monitoring to recognize fetal asphyxia may help in improving morbidity and mortality from meconium aspiration syndrome.

Blood Gas Analysis

The significance of meconium staining of the liquor amnii during labour.

Labour, labour outcome and fetal outcome were compared in 200 patients with meconium-stained amniotic fluid and in 200 matched controls with clear liquor amnii. All patients were subjected to a standardized form of management. The caesarean section rate was higher in the meconium group because of a higher incidence of cephalopelvic disproportion and fetal distress. In distinguishing between thick and thin meconium, no differences in labour or fetal outcome were found. The finding of meconium in the latent phase of labour seemed to be more ominous than during the active phase of labour.

Amniotic Fluid

Meconium passage: a new classification for risk assessment during labor.

The significance of MSAL as a sign of fetal distress is controversial. To better assess this condition, we present a classification of MSAL based on the timing and quantity of meconium passed and divided into early light, early heavy, and late passage of MSAL. By means of this classification with a problem-oriented risk assessment system, 2,933 pregnancies were prospectively evaluated during labor. The incidence of meconium passage was 22 per cent, of which early light constituted 53.6 per cent, early heavy 25.2 per cent, and late passage 21.2 per cent. Early heavy MSAL is associated with increased fetal and neonatal morbidity and death, and with a number of antecedent obstetric problems. Late passage of MSAL encountered no perinatal losses, but is associated with increased neonatal morbidity occurring late in labor. Early light MSAL, constituting over half of all our meconium group of patients, is not associated with any increased intrapartum or neonatal morbidity or death. This classification of MSAL is an effective tool for risk assessment during labor.

Amniotic Fluid

Significance of meconium in midtrimester diagnostic amniocentesis.

The importance of meconium passage as a sign of the third-trimester fetus in distress is well known. The significance of similar observations in the midtrimester fetus is much less certain. The increasing use of amniocentesis during the middle trimester for the diagnosis of genetic disease makes ascertainment of such data important. Ten instances of meconium-stained amniotic fluid in the last 514 amniocenteses performed at our institution for antenatal genetic diagnosis are reported. Seven pregnancies have ended at term with normal deliveries. Three pregnancies have terminated with fetal death. Meconium staining may be a sign of impending fetal death when passed during the second trimester. When accompanied by alpha-fetoprotein elevation two of three pregnancies terminated with fetal death.

Adult

Meconium ileus: laparotomy without resection, anastomosis, or enterostomy.

During the 14 yr from 1965 through 1978, 49 infants presented shortly after birth with intestinal obstruction due to impacted meconium. Three of these patients did not have fibrocystic disease. Eight patients were cured by a Gastrografin enema. There were 18 patients who had complications that included associated atresia, volvulus, and/or peritonitis. Various operations were done including resection with either primary anastomosis or enterostomy or varieties of the foregoing. Twenty-three babies had the simple uncomplicated form of meconium ileus. Eleven of these underwent resection and six patients died. Twelve patients were treated by laparotomy, ileotomy through a purse-string suture and prolonged irrigations using acetylcysteine. Of this group only one succumbed. This latter course of management is recommended for patients with simple uncomplicated meconium ileus as it involves no resection, no enterostomy, nor any primary anastomosis.

Cystic Fibrosis

Meconium aspiration syndrome.

Meconium aspiration syndrome is a perinatal problem which requires the full cooperation and coordination of obstetrical and pediatric personnel if it is to be avoided. Prompt, efficient delivery room management can minimize the sequelae of aspirated meconium. However, those infants who develop severe meconium aspiration syndrome are best managed in neonatal intensive care units where they can be closely monitored and vigorously treated.

Amniotic Fluid

Screening for cystic fibrosis by analysis of albumin in meconium.

A clinical study of the albumin content in meconium was performed on two categories of newborn infants: a screening series of 8,830 infants and a high-risk group for Cystic Fibrosis (CF) of 70 infants. A single radial immunodiffusion technique and test strips were used. Three CF infants were detected in the screening series (1:3,000) and 16 in the high-risk group. The diagnostic accuracy for CF was fairly good. The specificity was 99.8% for the immunodiffusion technique and 99.2% for test strips. A high concentration of albumin in meconium was found not only in CF but also in preterm babies and infants with gastrointestinal disturbances, such as atresias, malaena neonatorum and malabsorption syndromes. The sensitivity was 90% for the immunodiffusion technique and 78% for the test strip. False-negative results were probably due to proteolytic activity and might be avoided if the samples are stored at a low temperature before analysis. CF screening of all meconiums by the use of test strips followed by analysis of positive tests by the immunodiffusion technique is suggested.

Albumins