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Biomedical subjects

R M Nelson

Publications and source records attributed to R M Nelson.

At least 91 records · Page 5Linked to original sources
PubMed1987

Theophylline treatment in the neonate with apnea: effect on growth hormone, thyroid hormone and TRH induced TSH secretion.

Caffeine has been shown to markedly alter growth hormone (GH), thyroid stimulating hormone (TSH), and thyroid hormones in animal studies. Similar studies in the human are lacking. To determine the effect of theophylline treatment on endocrine function in neonates with apnea, 10 infants were studied prospectively pretreatment, immediately following therapeutic blood levels of theophylline, at 2, 4, and 6 weeks thereafter and finally 2 weeks after discontinuation of theophylline. T4, free T4, T3, GH, and basal and stimulated TSH were measured at each study period. Results show no significant difference consequent to theophylline therapy on basal thyroid or GH secretion and thyrotropin-releasing hormone (TRH) induced TSH response at any study interval. We conclude there is no evidence to suspect abnormality occurring in growth, thyroid function and GH secretion in neonates receiving theophylline for breathing disorders.

Apnea↗
PubMed1987

Developmental intervention for low birth weight infants: improved early development outcome.

This prospective longitudinal study was designed to evaluate the effects of a multidisciplinary infant development program (IDP) on the mental and physical development of low birth weight infants (less than 1,800 g). Infants in the neonatal intensive care were randomly assigned to the IDP or to traditional care (control group). IDP infants received developmental interventions in the hospital and at home through the first 2 years of life. Counseling and parenting education were provided to their parents during this same period. The control group received all the postnatal care and referrals customarily given in traditional care. Both IDP and control infants were enrolled in an independent follow-up program, which used the Bayley Scales of Infant Development in a blind evaluation design. The IDP group had a significantly lower incidence of developmental delay (P less than .05) and scored significantly higher than the control group (P less than .05) on mean mental and physical indices at 12 and 24 months of adjusted age.

Counseling↗
PubMed1987

Effects of asphyxia on telencephalic microvessels of premature beagle pups.

The authors identified alterations in the brain microvasculature of the premature Beagle pup that could be attributed to asphyxia and potentially associated with the etiology of intraventricular hemorrhage (IVH). Beagle pups were delivered by cesarean section six days before their predicted whelping date and exposed to an alternating protocol of asphyxial episodes known to produce IVH. Data from the telencephalic microvasculature at both the germinal matrix (an area susceptible to IVH) and the borderzone cerebral cortex (an area rarely involved in hemorrhage) were analyzed. The germinal matrix microvessels responded differently to asphyxia than the cortical vessels. The germinal matrix microvessels maintained junctional complexes and intraluminal microvilli, and increased in cross-sectional luminal area following asphyxia; however, total vessel cross-sectional area did not change. After the asphyxial insult, cortical microvessels no longer exhibited intraluminal microvilli and increased in both total cross-sectional area and luminal area. The number of junctional complexes in cross-sections of cortical vessels was significantly reduced due at least in part to the narrowing of the endothelial cell lateral borders. The data provide indirect evidence to substantiate vasodilation speculated to be due to an increased cerebral blood flow to telencephalic vessels (both the germinal matrix and cerebral cortex) following asphyxia. The data also suggest differential rates of maturation between germinal matrix and cortical microvessels.

Animals↗
PubMed1986

Single-antibiotic use for penetrating abdominal trauma.

A prospective randomized study compared the use of moxalactam disodium vs clindamycin phosphate and tobramycin sulfate for treatment of 190 patients with penetrating abdominal trauma. Twenty-seven patients were disqualified because of early death or failure to follow the protocol. The patients in each group were comparable regarding the cause and severity of injury. No significant difference was seen in the incidence of intra-abdominal infection between the moxalactam-treated group (13%) and the clindamycin- and tobramycin-treated group (9%). The intra-abdominal infection rate in patients with colon injuries (21%) was significantly increased when compared with the patients without colon injuries (6%), but the antibiotic regimen did not significantly change the infection rate. No evidence of bleeding problems from moxalactam were noted. Changes in prothrombin and partial thromboplastin times appeared to be related to shock rather than the use of moxalactam. The most severe coagulopathies occurred prior to moxalactam therapy and were seen only in those patients who had shock requiring 10 or more units of blood. Moxalactam is as effective as combination (clindamycin and tobramycin) antimicrobial therapy in patients with penetrating abdominal trauma.

Abdominal Injuries↗
PubMed1986

Telencephalic microvessels of premature beagle pups.

The ultrastructural morphologic and morphometric characteristics of the telencephalic microvasculature of both germinal matrix and border-zone cerebral cortex are analyzed from premature beagle puppies delivered by caesarean section in order to determine whether differences in the matrical vessels could account for their susceptibility to intraventricular hemorrhage. The germinal matrix microvessels are immature, since they contain intraluminal microvilli and junctional complexes (primarily tight junctions) that are not continuous between the lateral endothelial cell walls. The number of junctional complexes per vessel cross-section is less than either cortical vessels from the same premature animals or tissue from either site in full-term animals. Morphometric data on the cross-sectional area of vessels from the two sites indicate that the germinal matrix vessels have a significantly larger cross-sectional area than the cortical vessels. The increase is due almost exclusively to a larger endothelial cell area per cross section. This pattern is an altogether different one from that seen in the term animals. There the germinal matrix vessels exhibit a steadily decreasing luminal area from birth through 72 hr, whereas endothelial cell cross-sectional area is static. Here the luminal cross-sectional area is smaller, but both endothelial cell and total vessel cross-sectional areas are significantly larger. Structural components of the blood-brain barrier undergo active modifications during the late prenatal period that are distinct from the modifications during the immediate postnatal period.

Animals↗
PubMed1986

Coronary bypass surgery early after thrombolytic therapy for acute myocardial infarction.

The safety of coronary bypass operations after coronary reperfusion with streptokinase for acute myocardial infarction is not well documented. Therefore we studied 23 consecutive patients (mean age, 59.5 years; 22 men) undergoing bypass operations a median of 5 days (range, 1 to 23 days) after thrombolysis (streptokinase). The control group consisted of 169 concurrent patients of similar mean age (58.8 years) having bypass operations for standard indications. The preoperative angiographic ejection fraction was 68 +/- 14% in the control patients and 61 +/- 14% in the streptokinase group (p less than 0.05). The number of diseased vessels (70% stenosis or greater) averaged 2.6 in control and 2.3 in streptokinase patients. A previous myocardial infarction had occurred in 42% of the controls and all of the streptokinase patients. Aortic cross-clamp times did not differ between the two groups (80 +/- 35 minutes for the controls and 68 +/- 25 minutes for the streptokinase group). Cardiopulmonary bypass times were similar: 108 +/- 45 minutes in the controls versus 109 +/- 28 minutes in the streptokinase group. Grafts per patient averaged 3.7 +/- 1.5 for the controls versus 2.8 +/- 1.1 for the streptokinase patients (p less than 0.01). Difficult operative hemostasis was noted in 4% of both groups. Inotropic support was given postoperatively to 11% of the control and 13% of the streptokinase patients (p = not significant). Measured blood loss during the first 48 hours postoperatively was similar, averaging 809 ml in controls and 776 ml in the streptokinase group. Blood product replacement was also comparable: mean, 713 ml in the control group versus 759 ml in the streptokinase group.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiopulmonary Bypass↗
PubMed1986

The economic implications of infection in cardiac surgery.

To assess the economic impact of infection, the records of 496 patients aged 18 to 82 years (mean, 61 years) undergoing open-heart operations in 1981 and 1982 were reviewed, and the costs (length of stay, hospital charges, pharmacy charges) were compared for matched pairs of patients with and without infection who had coronary artery bypass grafting (CABG) procedures. Patients received a 5-day regimen of prophylactic cephalosporin. Operative site infections occurred within 6 months of operation in 17 patients (3.4%), urinary tract infections in 9 (1.8%), and pulmonary infections in 6 (1.2%). Early and late mortality was each 2%. No deaths were infection related, and no postoperative bacterial endocarditis occurred (minimum one-year follow-up). For the matched CABG patient in whom a postoperative wound infection developed, the average length of hospital stay was 16.7 days longer and the average hospital bill was $8,118 greater, with the average cost to the hospital $6,605 greater.

Adolescent↗
PubMed1986

Risk of hypoventilation in premature infants in car seats.

We examined 30 newborn infants for respiratory compromise before, during, and after placement in a recommended car seat restraining device. Twelve infants were premature with a history of apnea, eight were premature without known apnea, and 10 were born at term. Both premature groups had significant decreases in oxygen saturation while in the car seat (P less than 0.01) and more frequent desaturation episodes less than 80% (P less than 0.001). Premature infants with a history of apnea had more bradycardia events (P less than 0.05). No normal term infant had any of these problems. In addition, oxygen saturation trended downward from baseline for all premature infants during the recovery interval (P = 0.07). We conclude that currently available car seats may place premature infants at risk for significant hypoxia and ventilatory compromise.

Apnea↗
PubMed1986

Outcome of cardiopulmonary resuscitation in the neonatal intensive care unit.

This retrospective review of 83 infants undergoing CPR in the neonatal ICU of a teaching hospital found that 12 (14%) patients were discharged from the hospital and seven (8%) were alive at least 1 yr after discharge. Of these seven, five appeared neurologically intact. From another perspective, 41% (12/29) of the patients who survived at least 24 h after CPR were discharged alive. Factors significantly (p less than .05) associated with poor outcome included sepsis, oliguria 24 h before and/or after arrest, prematurity, and intraventricular hemorrhage. Variables significantly (p less than .05) related to good outcome were the need for intubation during resuscitation and the diagnosis of major congenital anomalies. Intraventricular hemorrhage was the single most powerful variable in the regression analysis. Outcome statistics from this study were strikingly similar to currently available adult data.

Cerebral Hemorrhage↗
PubMed1986

Fetal response decrement: true habituation?

Preliminary evidence suggests that fetal movement in response to vibrotactile stimulation "habituates" with repeated exposure. If demonstrated in fetuses, the habituation paradigm may be useful as a measure of fetal well-being or as a predictor of neonatal outcome. However, the ability of the fetal response decrement phenomenon to meet criteria for habituation which would distinguish it from simple receptor fatigue has not been evaluated. In this study, fetuses were exposed to two different frequencies of vibration applied to the maternal abdomen. Fetal movement was observed on an ultrasound monitor. An inverse relationship between the strength of the stimulus and rapidity of the response decrement was not observed. However, return of the response to presentation of a novel stimulus, response decrement to repetition of the second stimulus, and more rapid response decrement upon re-presentation of the original stimulus suggest that the fetal response decrement phenomenon is true habituation.

Arousal↗
PubMed1986

Blood loss at vaginal delivery.

Although the accurate assessment of blood loss at vaginal delivery is clinically important in terms of maternal morbidity and mortality, the quantity is usually underestimated. We present a simple, practical, and convenient method of quantitating blood loss at vaginal delivery. The method of vaginal delivery (spontaneous versus forceps) does not significantly affect blood loss; an episiotomy, a laceration, or both may.

Amniotic Fluid↗
PubMed1986

Antenatal prediction of sex.

Current recommendations suggest that prospective parents be informed of the fetal sex following an amniocentesis--if the parents express a desire for that information. Genotype does not in all cases accurately predict the appropriate sex of rearing. A case is discussed involving an infant with ambiguous genitalia who prior to birth had been designated a male, based on genotype obtained following amniocentesis. Caution is urged in predicting sex antenatally.

Adult↗