DNA content and differentiation of root apical cells of Brassica rapa plants grown in microgravity

Root cap is proposed to be a graviperceptive tissue in the plant root, and it is composed of several cell types. One such cell type, the columella cells, are thought to initiate the gravity-induced signal transduction cascade, and these cells arise from the activity of the meristematic zone of the root cap. There is, in fact, a continuum of cells in the central column of the root cap representing the meristematic cells, developing columella cells, mature cells, and those that will soon be sloughed off into the soil. In order to study the functional roles of the root cap cells in gravity-sensing, we compared the ultrastructural organization, differentiation, and DNA content in the meristematic, elongating, and differentiating cells of root tips in Brassica rapa plants grown in space microgravity and at 1g. The experiments were also designed to determine the reactions of root cap cells in both main roots (in which the original root cap was present in an embryonic form within the seed) and lateral roots (in which the root cap formed completely in space after seed germination on orbit) to the space microgravity. This study (ROOTS) was performed in collaboration with the B-PAC experiment on the Space shuttle "Columbia" mission STS-87 (Collaborative US/Ukrainian Experiment (CUE) during November 19-December 5, 1997.

Acute fetal asphyxia and permanent brain injury: a retrospective analysis of current indicators

OBJECTIVE

To determine whether a term neonate who has had sufficient intrapartum asphyxia to produce persistent brain injury will manifest the following four criteria: profound acidemia (arterial pH <7.00), an APGAR score < or =3 for 5 min or longer, seizures within 24 h of birth, and multiorgan system dysfunction.

METHODS

Singleton, liveborn, neurologically impaired neonates > or =37 weeks gestation who lived at least 6 days and had sufficient documentation of current intrapartum asphyxia criteria were retrospectively analyzed. Of these infants, solely neonates with acute fetal asphyxia due to a sudden prolonged FHR deceleration that lasted until delivery from a catastrophic event, e.g., uterine rupture, cord prolapse, were included. Organ system dysfunction was defined by separate criteria for each organ system. Dysfunction in one or more was defined as multiorgan system dysfunction.

RESULTS

Of the 292 eligible infants in the registry, 47 satisfied the entry criteria. In these 47 neonates, 10 (21%) satisfied all 4 criteria for intrapartum asphyxia.

CONCLUSIONS

Our retrospective study suggests that currently used indicators to define permanent fetal brain injury are not valid.

Does the onset of neonatal seizures correlate with the timing of fetal neurologic injury?

The onset of seizures after birth has been considered evidence of an intrapartum asphyxial event. The present study was undertaken to determine whether the timing of neonatal seizures after birth correlated with the timing of a fetal asphyxial event. Thus, singleton term infants diagnosed with hypoxic ischemic encephalopathy and permanent brain injury had a mean birth to seizure onset interval of 9.8 +/- 17.7 (range 1-90) hours. When these infants were categorized according to their fetal heart rate (FHR) patterns, the acute group (normal FHR followed by a sudden prolonged FHR deceleration that continued until delivery) tended to have earlier seizures than infants did within the tachycardia group (normal FHR followed by tachycardia, repetitive decelerations, and diminished variability) and the preadmission group (persistent nonreactive FHR pattern intrapartum). These seizure intervals were as follows: acute, 6.6 +/- 18.0 (range 1-90) hours; tachycardia, 11.1 +/- 17.1 (range 1-61) hours; and preadmission, 11.8 +/- 17.9 (range 1-79) hours (p < 0.05). But the range varied widely and no group was categorically distinct. In conclusion, the onset of neonatal seizures after birth does not, in and of itself, appear to be a reliable indicator of the timing of fetal neurologic injury.

Future financial neonatal shock

In a changing economic climate, the neonatologist must be aware of all of the forces that can affect the practice of neonatology. In addition to clinical issues, billing and reimbursement must take into account physician work and common procedural terminology (CPT) codes, which accurately describe the medical services and procedures delivered. An understanding of this coding and resource-based work unit system is necessary to prevent financial loss. The influence of managed care, capitation, fixed per-case reimbursement, practice guidelines and care maps have already seriously affected clinical practice patterns. The neonatologist must be proactive in negotiating contracts using historic information and outcome data to define and defend the quality of care provided.

Neonatal nucleated red blood cell and lymphocyte counts in fetal brain injury

OBJECTIVE

To determine whether neonatal lymphocyte or nucleated red blood cell (RBC) counts can be used to date fetal neurologic injury.

METHODS

Singleton, term infants with hypoxic-ischemic encephalopathy, permanent neurologic impairment, and sufficient laboratory data were divided into two groups: infants with preadmission injury, manifested by a nonreactive fetal heart rate (FHR) pattern from admission until delivery; and infants with acute injury, manifested by a normal FHR pattern followed by a sudden prolonged FHR deceleration. Lymphocyte and nucleated RBC values were compared with published high normal counts for normal neonates: 8000 lymphocytes/mm3 and 2000 nucleated RBCs/mm3.

RESULTS

The study population consisted of 101 neonates. In the first hours of life, lymphocyte counts were elevated among injured newborns, and then the counts rapidly normalized. Brain-injured neonates were 25 times more likely to have a lymphocyte count greater than 8000 than were normal neonates (54 [62%] of 87 versus 6 [7%] of 84; odds ratio 25.5; 95% confidence interval 8.8, 80.1; P < .001). The mean lymphocyte count tended to be higher in the preadmission-injury group than in the acute-injury group. In comparison, nucleated RBC values were not correlated as strongly with neonatal hours of life; nucleated RBC counts tended to be higher and persist longer among neonates with preadmission injury than among those with acute injury.

CONCLUSION

Compared with normal levels, both lymphocyte and nucleated RBC counts were elevated among neonates with fetal asphyxial injury. Both counts appear to be more elevated and to remain elevated longer in newborns with preadmission injury than in infants with acute injury. However, the rapid normalization of lymphocyte counts in these injured neonates limits the clinical usefulness of these counts after the first several hours of life.

Intrapartum fetal asphyxial brain injury with absent multiorgan system dysfunction

Current understanding of the physiologic mechanisms of intrapartum fetal asphyxial brain injury has suggested a strong association with multiorgan system injury. Thus the purpose here is to describe 14 cases of severe fetal brain injury with absent multiorgan system dysfunction (MSD). The study population was drawn from a national registry for brain injured infants. MSD was defined by clinical criteria demonstrated to reflect asphyxial injury to the pulmonary, renal, cardiac, hematologic, hepatic, and gastrointestinal systems. Involvement of one other organ in addition to the brain was defined as multiorgan system dysfunction. All infants were diagnosed with hypoxic-ischemic encephalopathy (HIE) in the neonatal period and went on to have permanent central nervous system (CNS) injury and MSD criteria were not met. Of the 292 term, singleton infants with HIE and permanent neurologic injury, 57 (20%) satisfied the entry criteria; of these, 14 (36%) had no MSD. The underlying basis for the fetal brain injury were: uterine rupture, 6 (43%), prolonged FHR deceleration, 5 (36%), fetal exsanguination, 1 (7%), cord prolapse, 1 (7%), and maternal cardiopulmonary arrest, 1 (7%). The mean duration of the prolonged FHR deceleration was 32.1 +/- 9.1 (range 19-51) minutes. All infants were later diagnosed with cerebral palsy. Intrapartum fetal asphyxial brain injury may not necessarily proceed through a physiologic mechanism in which the fetal circulation is centralized and endorgans damaged. These acute injuries, associated with a prolonged FHR deceleration, may be linked to severely decreased cardiac output and hypotension that cause vulnerable portions of the brain to be injured before other organs.

Nucleated red blood cells: an update on the marker for fetal asphyxia

OBJECTIVE

Our goal was to update our experience with nucleated red blood cells as a marker for fetal asphyxia and to determine whether a relationship exists between the presence of nucleated red blood cells and long-term neurologic impairment.

STUDY DESIGN

Nucleated red blood cell data from 153 singleton term neurologically impaired neonates were compared with cord blood nucleated red blood cells of 83 term nonasphyxiated newborns. Newborns with anemia, intrauterine growth restriction, and maternal diabetes were excluded. The group of neurologically impaired neonates was separated into the following subgroups: group I, persistent nonreactive fetal heart rate pattern from admission to delivery (n = 69); group II, reactive fetal heart rate on admission followed by tachycardia with decelerations and absent variability (n = 47); group III, reactive fetal heart rate on admission followed by an acute prolonged deceleration (n = 37). The first and highest nucleated red blood cell value and the time of nucleated red blood cell disappearance were assessed.

RESULTS

The mean number of initial nucleated red blood cells was significantly higher in the group of neurologically impaired neonates (30.3 +/- 77.5, range 0 to 732 per 100 white blood cells) than in the control group (3.4 +/- 3.0, range 0 to 12 per 100 white blood cells) (p < 0.000001). When the group of neurologically impaired neonates was separated on the basis of timing of the neurologic impairment, distinct nucleated red blood cell patterns were observed. Significant differences were obtained between each of the three groups of neurologically impaired neonates and the normal group, with respect to initial nucleated red blood cells (group I, 48.6 +/- 106.9; group II, 11.4 +/- 9.8; group III, 12.6 +/- 13.4; p < or = 0.000002). Maximum nucleated red blood cell values were higher in group I (mean 51.5 +/- 108.9) than in groups II and III combined (mean 12.7 +/- 11.9) (p = 0.0005). Group I also had a longer clearance time (119 +/- 123 hours) than groups II and III combined (mean 59 +/- 64 hours) (p < 0.001).

CONCLUSION

Our ongoing study indicates that nucleated red blood cells identify the presence of fetal asphyxia. When fetal asphyxia is present, distinct nucleated red blood cell patterns are observed that relate to the timing of fetal injury. In general, intrapartum injuries are associated with lower nucleated red blood cell values. Thus our data continue to support the concept that nucleated red blood cell levels may assist in determining the timing of fetal neurologic injury.

From how small is too small to how much is too much. Ethical issues at the limits of neonatal viability

In recent years, survival of the extremely low birthweight infant has dramatically improved. Morbidity, both short- and long-term, however, remains very high Costs in the currency of pain and suffering for the newborn, stress and financial burdens for the family, and dollars for society are extensive. The controversial questions that are discussed include: How small is too small? How much is too much? How far should we go? How much can we afford? Who should decide? What strategies should be followed to ensure such decisions are just?

Nucleated red blood cells: a marker for fetal asphyxia?

OBJECTIVE

Our purpose was to determine whether a relationship exists between the presence of nucleated red blood cells, hypoxic ischemic encephalopathy, and long-term neonatal neurologic impairment.

STUDY DESIGN

Nucleated red blood cell data from 46 singleton term neurologically impaired neonates were compared with cord blood nucleated red blood cells of 83 term nonasphyxiated newborns. The neurologically impaired neonates group was also separated as follows: nonreactive, nonreactive fetal heart rate from admission to delivery; tachycardia, reactive fetal heart rate on admission followed by tachycardia with decelerations; rupture, uterine rupture. The first and highest nucleated red blood cells value and the time to nucleated red blood cells disappearance were assessed.

RESULTS

The neurologically impaired neonates group exhibited a significantly higher number of nucleated red blood cells per 100 white blood cells (34.5 +/- 68) than did the control group (3.4 +/- 3.0) (p < 0.00001). When the neurologically impaired neonates are separated as to the basis for the neurologic impairment, distinct nucleated red blood cell patterns were observed. Overall, the nonreactive group exhibited the highest mean nucleated red blood cell (51.4 +/- 87.5) count and the longest clearance times (236 +/- 166 hours).

CONCLUSION

In this limited population, nucleated red blood cell data appear to aid in identifying the presence of fetal asphyxia. When asphyxia was present, distinct nucleated red blood cells patterns were identified that were in keeping with the observed basis for the fetal injury. In general, the closer the birth was to the asphyxial event, the lower was the number of nucleated red blood cells. Thus our data suggest that cord blood nucleated red blood cells could assist in the timing of fetal neurologic injury.

Neonatal management of the very low birth weight infant: the use of surfactant

The use of surfactant in the low birth weight infant with respiratory distress syndrome has undergone multicenter randomized clinical trials. This article addresses the properties of surfactant, the clinical aspects of surfactant replacement therapy and the implications for future research.

Polyhydramnios: fetal and neonatal implications

Polyhydramnios is a common obstetric condition with a high incidence of neonatal morbidity and mortality. Early prenatal diagnosis is essential to provide proper perinatal care. Understanding the physiology of these defects can assist the entire perinatal team in optimizing care for the mother, fetus, and infant.

The effectiveness of a cardiopulmonary resuscitation program for mothers of newborn infants

To investigate the effectiveness of a 15-minute videotape on how to perform cardiopulmonary resuscitation (CPR) on a newborn infant, 28 mothers of normal term babies completed a 12-item test on infant CPR before, immediately after, and 4-6 weeks after viewing the videotape. Statistical analysis showed that the videotape significantly improved scores on the first post-test as compared with the pre-test. At final testing, scores were significantly lower than at the first post-test, but still significantly higher than the pre-test scores. CPR education should be adopted by all institutions providing obstetrical care.

Sudden infant death syndrome in infants evaluated by apnea programs in California

Home apnea/bradycardia monitoring is frequently used in the management of infants at increased risk for sudden infant death syndrome (SIDS). However, some infants have died despite evaluation by infant apnea programs, and the benefits of home monitoring remain unproven. To determine the SIDS rate and risk factors of infants evaluated by infant apnea programs, 31 apnea programs and ten home monitor vendors in California were surveyed. Eleven (35%) of the apnea programs and four (40%) of the vendors responded. Information was obtained on 26 infants who died. Thirteen (50%) deaths were due to SIDS. Abnormal sleep studies did not predict death. Fifteen infants died despite a recommendation for home monitoring. Seven deaths occurred in association with technical errors or noncompliance with monitoring. Four deaths were due to nonaccidental trauma. The apnea programs evaluated 3,406 infants during a 5-year period; 1,841 had monitoring recommended. Term infants with apnea, subsequent siblings of SIDS victims, and infants evaluated at referral centers were more likely to have monitoring recommended than premature infants with apnea or infants evaluated at nonreferral centers (P less than .0001). Infants who had monitoring recommended were at equal risk of dying of SIDS as those who did not.

Diagnosis of Meckel's diverticulum by radioisotope scanning

The clinical illness observed in a 5-month-old infant with Meckel's diverticulum is described. A sodium pertechnetate radioisotope scan was employed to confirm the clinical impression. The technical procedure, evaluation, and importance of the radioisotope study is discussed.