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Biomedical subjects

T A Merritt

Publications and source records attributed to T A Merritt.

At least 127 records · Page 7Linked to original sources
PubMed1980

Glutaric aciduria Type II.

Two infants have been studied with glutaric aciduria Type II. The clinical presentation was of an overwhelming illness very early in life; both infants died in the neonatal period. One had dysmorphic features. An acrid odor may be a clue to the diagnosis. Neonatal acidosis, hypoglycemia, and hyperammonemia are characteristic. Organic acid analysis revealed massive lactic aciduria and glutaric aciduria. A variety of other dicarboxylic acids and hydroxy acids and amino acids were found in elevated amounts in body fluids, along with elevated concentrations of butyric, isobutyric, 2-methylbutyric, and isovaleric acids. The pattern of metabolites accumulated is consistent with deficient activity of a number of acyl-CoA dehydrogenases.

Amino Acids↗
PubMed1980

Transcutaneous oxygen monitoring during neonatal transport.

The use of transcutaneous PO2 monitoring during neonatal transport was found to be feasible and clinically useful in maintaining the partial pressure of arterial oxygen within a desired range. Adjustment of fractional inspiratory oxygen (FIO2) to maintain transcutaneous PO2 between 50 to 70 torr resulted in a greater number of infants arriving at a tertiary center without either hypoxemia or hyperoxemia.

Humans↗
PubMed1979

Acceleration of pulmonary surfactant maturation in stresses pregnancies: a study of neonatal lung effluent.

To determine the maturation of pulmonary surfactant at birth, phospholipid patterns in tracheal or pharyngeal aspirates of 54 newborn infants were analyzed by two-dimensional thin-layer chromatography. The compositions of phospholipids and their surface tension-lowering abilities were assessed after gestations with various complications. Preterm infants with respiratory distress syndrome (RDS) lacked phosphatidylglycerol and had lower lecithin/sphingomyelin ratios than infants without RDS. An acceleration of both phosphatidylcholine (lecithin) and phosphatidylglycerol concentrations was observed in 21 preterm infants born after prolonged rupture of the membranes and treatment with isoxuprine. In these infants, the phospholipid pattern of lung effluent was similar to that of term infants even at gestational ages less than or equal to 30 weeks. Biochemical lung maturation was delayed in aneccephalic infants, infants of diabetic mothers, and one infant of a mother with hypothyroidism.

Birth Weight↗
PubMed1979

Patent ductus arteriosus treated with ligation or indomethacin: a follow-up study.

The course and complications of fifty-two infants with patent ductus arteriosus requiring closure were assessed prospectively. Twenty-six infants with a PDA received indomethacin for pharmacologic closure of the PDA, and 26 underwent ligation. The current study analyzes and compares the longitudinal follow-up with respect to somatic growth, neurologic function, psychomotor and mental development, and renal, ophthalmologic, and audiologic function in 21 infants in each group who entered the follow-up. No selective morbidity was attributable to PDA closure with indomethacin when compared to surgically treated infants.

Child Development↗
PubMed1978

Closure of the patent ductus arteriosus with ligation and indomethacin: a consecutive experience.

This report summarizes a consecutive experience with 59 preterm infants with clinical, radiographic, and echocardiographic findings of a large patent ductus arteriosus. Thirty-five infants who met defined criteria received indomethacin, and 24 infants underwent PDA ligation. Analysis of the clinical course of these infants revealed no selective indomethacin morbidity and suggests that infants undergoing ligation require more prolonged ventilator therapy with increased exposure to FiO2 greater than or equal to 0.3. Mortality rates between ligated and pharmacologically treated groups were similar. This study documents that inhibition of prostaglandin synthesis to constrict and close the PDA in the premature infant is an effective alternative to operative closure.

Ductus Arteriosus, Patent↗
PubMed1978

Radiographic and echocardiographic evaluation of newborns treated with indomethacin for patent ductus arteriosus.

A series of 33 consecutive preterm newborns who were treated with indomethacin, a drug which acts to close the patent ductus arteriosus, were studied retrospectively to examine the efficacy of chest radiography and echocardiography in diagnosing the presence of a significant patent ductus arteriosus. Radiographic changes in pulmonary vascular engorgement, pulmonary edema, and cardiac size on the anteroposterior film tended to precede the clinical changes of shunt appearance and resolution. The echocardiographic left atrial to aortic ratio (LA/Ao) supplemented the radiographic findings. The time of disappearance of the ductus arteriosus shunt, as judged by clinical findings, was identified accurately by radiographic and echocardiographic findings in the majority of cases; errors of under- and overestimation occurred in a minority of patients. In assessing both the presence and the resolution of the shunt, greater reliability was possible by using both radiographic and echocardiographic findings than by using either method alone.

Diagnostic Errors↗
PubMed1976

Sudden infant death syndrome temperament before death.

A retrospective study was made of the behavioral patterns of 46 infants whose deaths were attributed to the sudden infant death syndrome. Controls were the victims' siblings. Data concerning the infants' behavioral pattern were collected retrospectively from the parents, utilizing a modification of the Carey temperament questionnaire. The parents' recollection of the victims indicated that they: (1) had less intense reactions to environmental stimuli, (2) were less active physically, (3) were more breathless and exhausted during feeding, and (4) had more abnormal cries. The behavioral characteristics had a positive correlation with various postmortem evidences of antecedent chronic hypoventilation and hypoxemia. It would be a serious error for any parent to be told that their infant was at risk based on the behavioral pattern reported retrospectively by parents of victims of SIDS, because the pattern is also a common one in other infants.

Child Behavior↗
PubMed1976

Diminished pulmonary lecithin synthesis in acidosis: experimental findings as related to the respiratory distress syndrome.

Lung slices from term fetal rats were incubated in vitro at various pH values and the rates of the two de novo pathways for lecithin biosynthesis were determined by measuring the conversion of either 14C-choline (pathway 1) or 14C-methionine (pathway 2) to the phospholipid. It was observed that the choline pathway, but not phosphatidylethanolamine methylation, is pH-sensitive with maximum rates occurring at pH levels between 7.3 and 7.5; significantly less activity was found at pH levels between 7.0 and 7.2 and at pH levels between 7.6 and 8.0. Adjustment of the pH from 7.0 to 7.4 in vitro simulating the clinical correction of acidosis by alkali infusion was found to increase the conversion of choline to lecithin to a rate approximating that observed at pH 7.4. Since lecithins are the principal phospholipid components of pulmonary surfactant, and since pathway 1 is predominantly responsible for lung lecithin synthesis, the demonstration of impaired production with reduced pH offers a biochemical explanation for the pathophysiological effects of acidosis in the respiratory distress syndrome. A comparison of pH effects on choline pathway rate with the pH profiles of pathway enzymes suggests that these effects are mediated by the catalysts of lecithin synthesis.

Acidosis↗
PubMed1975

Sudden infant death syndrome: the role of the emergency room physician.

Prompt recognition by the emergency room attending physician of the occurrence of SIDS provides the opportunity to deal empathetically with parents, thus ameliorating to some degree their profound psychiatric trauma. Among the responsibilities of the emergency room physician are 1) talking with the parents, 2) obtaining postmortem examination permission and making certain that the results of the autopsy are promptly communicated to the parents and to the family physician, and 3) arranging follow-up psychologic support for the parents. Awareness of the frequency of the sudden infant death syndrome and of the potentially preventable psychiatric morbidity among parents by the emergency health care personnel can do much to reduce the tragic toll of SIDS.

Emergency Service, Hospital↗
PubMedDate not supplied

Prostaglandin E1 responsive ductus at 11 months of age.

An 11-month-old boy with congestive heart failure and an intermittently closing patent ductus arteriosus (PDA) is presented. During cardiac catheterization, the ductus proved responsive to prostaglandin E1. Permanent closure of the PDA could not be attained with indomethacin. The infant underwent surgical ligation of the PDA.

Alprostadil↗
PubMedDate not supplied

A review of guidelines for the discharge of premature infants: opportunities for improving cost effectiveness.

Although significant advances in the medical management of acutely ill preterm infants has resulted in unprecedented rates of survival, issues surrounding the convalescent care, discharge preparation, and readiness of parents or other caregivers has been less well studied and represents the art of medicine. We have summarized various guidelines for early discharge of the premature infant and provide our own recommendations for physiologic stability, social requirements, teaching needs of caregivers, and the coordination of community resources. Technology-dependent infants pose even greater complexities. Some infants and families adapt to extensive use of technology in the home. In other situations, basic infant care is difficult to achieve. What are the essential components for successful early discharge, and how can the studies involving selecting families be made universal? How can NICUs better prepare fathers and mothers for premature parenthood? To what extent are we overwhelming families with additional responsibilities and expectations that may compromise their competency in basic parenting? Furthermore, the degree of provider variation in evaluating and providing for discharge planning is now being more carefully studied. In some circumstances, integrated teams in the NICU have facilitated the discharge process, saving days of hospitalization, whereas in other circumstances, adherence to discharge planning guidelines have lengthened the stay in the NICU and resulted in higher costs. Failure to back transport infants to community NICUs has contributed to deregionalization efforts in some regions and increased cost of care. Efforts to establish regional referral networks with common guidelines and developmentally focused care should lead to a reduction in NICU costs and charges.

Cost-Benefit Analysis↗
PubMedDate not supplied

Focal necrosis of the white matter (periventricular leukomalacia): sonographic, pathologic, and electroencephalographic features.

Eleven preterm infants (gestational ages 27-35 weeks) with echogenic paraventricular white matter identified shortly after birth were studied with serial echoencephalograms to fully delineate the sonographic findings characterizing the pathologic stages of white-matter necrosis. Echoencephalograms were compared with autopsy findings and CT scans. Cerebral function was assessed by electroencephalograms and later by neurodevelopmental evaluations. Echogenic areas were observed in the paraventricular white matter in the acute stage. Microscopically, the echogenic white matter consisted of vascular congestion and petechial hemorrhages, but not always with foci of necrosis. Anechoic areas, which characterized the chronic stage, corresponded to cavitary lesions, and these generally appeared within 2 weeks of birth. However, six infants had anechoic lesions by day 4, suggesting that the onset of white-matter damage was antenatal. CT showed mildly decreased attenuation when paraventricular echogenic areas alone or in association with small anechoic areas were observed. Markedly decreased attenuation on CT scans corresponded to large anechoic areas. Resolution of the sonographic and CT findings did not indicate normalization of the white matter since all surviving infants were neurologically abnormal at 1 year. Electroencephalograms with central (rolandic) positive sharp waves were associated with echogenic white matter alone or with evolving anechoic areas. All patients with positive sharp waves on electroencephalograms had large anechoic areas in later studies. Early and serial echoencephalograms are necessary to evaluate white-matter necrosis in preterm infants. When echogenic white matter is identified, electroencephalography can suggest the presence of white-matter necrosis.

Echoencephalography↗