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Biomedical subjects

M C Yoder

Publications and source records attributed to M C Yoder.

64 records · Page 4Linked to original sources

Immunotherapy of neonatal septicemia.

This chapter has reviewed the deficiencies in immune defense that place the neonate, particularly the premature infant, at increased risk of invasive bacterial disease. We also have reviewed the literature on the rationale for exchange transfusion, granulocyte transfusion, intravenous immunoglobulin, and fibronectin administration as immunotherapeutic agents in infected infants. There have been no randomized controlled trials of exchange transfusion, immunoglobulin, or fibronectin administration in human infants with infection. Granulocyte transfusion in the infected newborn infant has been studied in a controlled fashion, but the results of clinical trials are conflicting. Thus, all of these interventions appear to need further evaluation. We therefore recommend that in the septic newborn infant with neutropenia and an I/T ratio greater than or equal to 0.8, who fails to demonstrate a favorable response to conventional antibacterial chemotherapy and cardiopulmonary support, the administration of approximately 1 X 10(9) irradiated granulocytes per kg may be beneficial. In the absence of equipment to isolate the granulocytes, a double-volume exchange transfusion with fresh heparinized whole blood will provide a similar quantity of functional phagocytes.

Antibody Formation↗

Endotoxin-induced changes in nitrogen metabolism.

Intraperitoneal administration of a sublethal dose of E. coli endotoxin to fasted rats produced within 12 hrs a rise in plasma ammonia, urea, glutamine, glutamate and aspartate as compared to controls. At this time, hepatic ureagenesis also increased as did the levels of glutamate, glutamine, aspartate, alanine and asparagine. However, liver glucose and ketone levels were unchanged. Hepatic [ATP]/[ADP] ratios declined in endotoxin-treated animals and there was an oxidation of mitochondrial pyridine nucleotides and a reduction of cytosolic pyridine nucleotides. The results suggest that impairment of nitrogen metabolism is an early effect of endotoxemia.

Amino Acids↗

Metabolic and mitochondrial morphological changes that mimic Reye syndrome after endotoxin administration to rats.

The administration of sublethal doses of Escherichia coli O111:B4 endotoxin to starved rats results in significant increases in plasma ammonia, free fatty acids, and serum lactate compared with starved controls. These metabolic alterations are associated with Reye syndrome-like histological findings of hepatic microvesicular fatty accumulation and hepatic ultrastructural evidence of mitochondrial pleomorphism with matrix disruption. This sublethal endotoxin model may help elucidate the relationship between the hepatic mitochondrial injury, characteristic metabolic impairment, and encephalopathy seen in patients with Reye syndrome.

Alanine Transaminase↗

Decreased fibronectin biosynthesis by human cord blood mononuclear phagocytes in vitro.

Cultured cord blood monocytes synthesize significantly less fibronectin than cultured monocyte-macrophages from adult peripheral blood. Biosynthesis of the second component of complement in vitro is similar for both cell systems. The monocyte-macrophages from neonates and adults have similar functional and morphologic properties in long-term cultures. The decreased monocyte-macrophage biosynthesis of fibronectin observed in vitro may be in part related to the reduced plasma fibronectin concentrations and reticuloendothelial system hypofunction which occur in newborn infants.

Adult↗

Decreased plasma fibronectin in neonatal sepsis.

Fibronectin is a large opsonic glycoprotein which promotes reticuloendothelial system clearance of bacteria, immune complexes, collagenous debris, and damaged platelets. The concentration of plasma fibronectin is decreased in the newborn infant; however, the role of fibronectin in the onset and course of neonatal sepsis is unknown. Serial plasma fibronectin levels were determined in 19 neonates with documented bacterial sepsis. Plasma fibronectin concentrations decreased significantly (P less than .001) in all study infants concurrent with the development of septicemia. Recovery of plasma fibronectin to normal levels occurred by day 5 in premature neonates and by days 7 to 10 in term neonates. Fibronectin deficiency and resultant reticuloendothelial system impairment may decrease the ability of newborn infants to resist or clear bacterial infections. An acute reduction in the concentration of plasma fibronectin may be a valuable marker for neonatal sepsis.

Bacterial Infections↗

Comparison of serum fibronectin, prealbumin, and albumin concentrations during nutritional repletion in protein-calorie malnourished infants.

Anthropometric measurements and serum fibronectin, prealbumin, and albumin concentrations were determined on admission and during the hospitalization of 20 noninfected infants with protein-calorie malnutrition. Serum fibronectin concentrations were significantly decreased on admission but increased to greater than normal serum values in 2 weeks. During this same interval, serum prealbumin values rose from significantly decreased to normal levels. Serum albumin concentrations and anthropometric measurements were not significantly elevated above admission levels until the fourth week of nutritional support. Serum fibronectin and prealbumin concentrations may serve as indices of the short-term efficacy of nutritional support in noninfected infants with protein-calorie malnutrition.

Anthropometry↗

Association of maternal lithium exposure and premature delivery.

Lithium is widely used and the treatment of choice for patients with manic-depressive illness. For pregnant patients with manic-depressive illness, however, the use of lithium during the first trimester of pregnancy may present an increased risk for fetal maldevelopment. We have recently cared for several large-for-gestational-age, prematurely born infants whose mothers were treated with lithium throughout pregnancy. To determine whether maternal lithium use during pregnancy may predispose to the onset of premature labor and fetal macrosomia, we reviewed records from the International Register of Lithium Babies and from a cohort of manic-depressive pregnant women. More than one third (36%) of infants reported to the International Register were born prematurely, and 37% of the premature infants were large for gestational age; 15% of the term infants were born large for gestational age. In the cohort group, manic-depressive mothers who received lithium during pregnancy had a 2.5-fold higher incidence of premature births than manic-depressive pregnant patients who did not receive lithium treatment. The incidence of large-for-gestational-age births in lithium-treated women in the cohort was not different from that of the general population or from manic-depressive women not treated with lithium. In summary, an association between maternal lithium therapy and premature delivery is reported. We recommend that women receiving lithium therapy during pregnancy be closely monitored for the onset of premature labor.

Adult↗

Controlled prospective randomized comparison of high-frequency jet ventilation and conventional ventilation in neonates with respiratory failure and persistent pulmonary hypertension.

OBJECTIVE: The objective of this study was to evaluate the efficacy and safety of high-frequency jet ventilation in near-term and term neonates with persistent pulmonary hypertension. STUDY DESIGN: Subjects for this prospective, randomized, controlled comparison study were recruited from neonates treated in a level-three neonatal intensive care unit that accepts referrals for extracorporeal membrane oxygenation. RESULTS: In patients treated with high-frequency jet ventilation (n = 11) acute improvement in oxygenation (p = 0.008), ventilation (p < 0.001), and oxygen indices (p < or = 0.01) was demonstrated while stable peak and mean airway pressures were maintained. Control group patients receiving high-frequency positive pressure ventilation with a conventional ventilator required increasingly higher peak inspiratory pressures (p = 0.005) to maintain oxygenation, ventilation, and oxygen indices. There were no significant differences in survival without use of extracorporeal membrane oxygenation, nor were there differences in duration of oxygen therapy, ventilation, and hospitalization; need for extracorporeal membrane oxygenation; or incidence of chronic lung disease. CONCLUSIONS: High-frequency jet ventilation acutely improves oxygenation and ventilation without significantly increasing morbidity. Therefore high-frequency jet ventilation may be a useful adjunct for stabilization of the conditions of neonates with severe persistent pulmonary hypertension. Conclusions about the efficacy of high-frequency jet ventilation in improving survival without the need for extracorporeal membrane oxygenation await multicentered, collaborative investigations with large cohorts of patients.

Analysis of Variance↗