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Biomedical subjects

R Baldwin

Publications and source records attributed to R Baldwin.

50 records · Page 3Linked to original sources

Movement and gastroesophageal reflux in awake term infants with "near miss" SIDS, unrelated to apnea.

Forty-five term infants who had a "near miss" for SIDS were studied with a continuous overnight polygraphic recording of endoesophageal pH, respiration, and ECG. Recordings were examined for occurrences of GER and for central apnea of 10 seconds or greater duration. There were 341 apneic events greater than or equal to 10 seconds recorded in 46 studies, with a mean of 7 +/- 7. In 91% of the infants, no apneas exceeded 15 seconds. Only 31 episodes of apnea greater than or equal to 10 seconds occurred during GER: in two of these episodes the apneic event was greater than or equal to 15 seconds. Twenty-four of the 31 apneas greater than or equal to 10 seconds during periods of pH less than 4 occurred in one infant. A total of 356 precipitous pH drops was recorded (mean 8.7 +/- 7.4). The pH drops occurred most frequently when the patient appeared to be awake (73%), and in 84% of events there was movement before and during the pH change. We conclude that the majority of these near miss SIDS infants had GER associated with movement during awake periods, without any temporal relationship to apnea. Although reflex apnea following GER may be seen in some term infants, this problem may be more significant for the immature infant.

Apnea↗

Sleep parameters and respiratory variables in "near miss' sudden infant death syndrome infants.

Twenty-nine near miss for sudden infant death syndrome and thirty normal infants between the ages of 3 weeks and 6 months were monitored polygraphically for 24 hours. The distribution of sleep and abnormal respiratory events were analyzed for both groups. On the basis of mixed and obstructive apnea, 12-hour nocturnal segments (8 PM to 8 AM) consistently distinguished near miss from normal infant groups between the ages of 3 weeks and 4.5 months. Daytime naps do not provide statistical differences sufficient to differentiate between the two groups. During sleep, abnormal respiratory events are more likely to occur between 1 AM and 6 AM, at least 40 minutes after sleep onset. Respiratory pauses show a significant increase just prior to waking (a strong respiratory stimulus). Any impairment of the arousal threshold during sleep will place near miss infants at increased risk.

Monitoring, Physiologic↗

Mixed and obstructive sleep apnea and near miss for sudden infant death syndrome: 2. Comparison of near miss and normal control infants by age.

Twenty-nine full-term near miss for sudden infant death syndrome (SIDS) and 30 normal control infants underwent 24-hour polygraphic monitoring. Several types of respiratory events during sleep (eg, central, mixed, and obstructive apnea, periodic breathing) were defined and tabulated. Analysis of these respiratory variables and comparison of groups of near miss and control infants indicated that between 3 weeks and 4 1/2 months of age only one variable was consistently different at a statistically significant level: the number of mixed and obstructive apnea greater than 3 seconds during total sleep time. This study also showed an increase in mixed and obstructive respiratory events during sleep at 6 weeks of age in control as well as in near miss infants.

Female↗

Obstructive sleep apnea and near miss for SIDS: I. Report of an infant with sudden death.

An infant girl followed up from birth to death at the University Medical Center had ""congenital stridor'' and a ""near miss for SIDS'' event at 3 months of age. As part of an ongoing SIDS research project, she underwent 24-hour polygraphic monitoring at 21 weeks of age. Sudden infant death occurred within 30 hours after the polygraphic study. Polygraphic data obtained from this infant are compared with those from control infants and other infants with near miss for SIDS who were of similar ages. The number of mixed and obstructive respiratory events during sleep was abnormally high on the infant's recording. Histologic findings, involving particularly the midline structures of the brain stem, are discussed.

Apnea↗

The effects of neurally active amino acids on pituitary gonadotropin secretion.

Several neurally excitant amino acids were injected into the third ventricle of anesthetized male rats, and plasma levels of luteinizing hormone (LH) and follicle stimulating hormone (FSH) were measured. LH levels increased following injections of 2.0 mum glutamate, lysine, or beta-alanine. Glycine (2.0 mum), alpha-alanine (2.0 mum), and 0.9% saline were ineffective in altering LH levels. None of the amino acids tested significantly altered FSH levels. Of the 3 amino acids which raised blood LH levels following an intraventricular injection, i.e., glutamate, beta-alanine, and lysine, only lysine caused a significant increase in LH levels following injection into the pituitary. The present study provides evidence for a possible role for certain neurally excitant amino acids in the neuronal control of LH secretion.

Alanine↗

Zearalenone production by Fusarium species.

One-hundred-and-thirteen isolates of Fusarium were tested for their ability to produce zearalenone on autoclaved corn. They belonged to the following species (number of producers per number tested): F. epispheria, (0/1); F. moniliforme, (0/8); Gibberella fujikuroi, (0/3); F. nivale, (0/7); F. oxysporum, (0/15); F. roseum, (31/51); F. solani, (0/9); F. tricinctum (3/19). The isolates of individual species produced the following amounts of zearalenone per gram of corn: 3 isolates of F. roseum (0.6 to 119 mug), 3 of F. roseum "Culmorum" (1 to 210 mug), 3 of F. roseum "Equiseti" (0.6 to 2.0 mug), F. roseum "Gibbosum" (115 to 175 mug), 21 of F. roseum "Graminearum" (0.2 to 230 mug), and 3 of F. tricinctum (0.2 to 6.0 mug). All isolates of F. roseum "Graminearum" which formed the perithecial stage of G. zeae (G. roseum) produced zearalenone. Production occurred by the wild but not the appressed cultural type. Zearalenone production by F. tricinctum was confirmed by a mouse bioassay.

Animals↗

Left-sided leg edema of the elderly: a common variant of the iliac compression syndrome.

BACKGROUND: Anatomically, the right common iliac artery crosses the left iliac vein and its accompanying lymphatics. We hypothesized that this situation could lead to a predominance of edema, telangiectasis, and venous varicosities on the left lower extremities of older persons. METHODS: To test this hypothesis, a research assistant who was blinded to the study goals examined 215 predominantly elderly residents of North Carolina homes for the aged and disabled. RESULTS: Among these subjects, 17.7 percent had predominantly left-sided edema, and 5.7 percent had predominantly right-sided edema (P < 0.001). When the 88 subjects with pitting edema greater than 3 mm were studied, 34.5 percent showed a left-sided predominance, and 6.9 percent showed a right-sided predominance (P < 0.001). In contrast, no significant difference was found in the lateralization of venous varicosities or of telangiectasis. CONCLUSIONS: Asymmetric edema is common and is usually left-sided in older persons. Compression of the left common iliac vein and its accompanying lymphatics by the right iliac artery, rather than overt clinical disease, might explain the majority of asymmetric edema seen in clinical practice.

Adult↗