Biomedical subjects
B Sternberg
Publications and source records attributed to B Sternberg.
Electron microscopic and biophysical studies of liposome membrane structures to characterize similar features of the membranes of Streptomyces hygroscopicus.
To characterize the novel non-planar plasma membrane structure of bacteria (wafer structure), liposome membranes from the bacterial lipid mixture and individual lipid fractions were prepared and investigated by freeze-fracture electron microscopy, microcalorimetry and 31P-NMR spectroscopy. The phospholipid content of the membranes is essential for the formation of the non-planar membrane structure and there is no indication that the formation of the structure is connected with temperature-induced lipid phase transition processes. An exaggerated form of the wafer structure (raspberry structure) is also visible and additionally, in both cases, many small spherical vesicles are observed. We suggest that both membrane features of the liposomal and bacterial membranes are induced by these vesicles, forming a hexagonal or cubic organization of vesicles on the cytoplasmic surface of the biological membrane, and in between the multilamellae in the artificial membranes.
[Brain abscess in the newborn infant (27 cases: initial electroclinical study, course].
The authors studied 27 brain abscesses in neonates. The neonates were divided in two groups: neonates with seizures and neonates without seizures. The authors tested the diagnostic and predictive value of the initial EEG aspect. They noted the absence of correlation between EEG focal abnormalities and localizations shown by the CT scan. They observed a severe electroclinical evolution in more than fifty percent of the cases presented.
[Medical behavior and sudden infant death].
The authors recall some hypothesis about factors of risk which are acknowledged as possible element of SIDS and may receive a treatment: gastroesophageal reflux, vagal hyperexcitability and enzymatic deficit.
Respiratory pauses and periodic breathing assessed by cardio-pneumography in normal infants and in SIDS siblings.
450 cardio-pneumograms (CPG) were performed on two successive nights in 68 controls and 235 SIDS siblings. The number of respiratory pauses greater than or equal to 5 sec and greater than or equal to 10 sec (NP) and the time of periodic breathing (PB) were calculated per 100 minutes of recording. Recordings were arranged into five age groups corresponding to the 1st, 2nd, 3rd, 4th and 5th-6th month of life. No significant differences in NP and PB were found when controls and SIDS siblings were compared separately within each age group, neither as a function of gestational age (less than 40 weeks GA vs greater than or equal to 40 weeks GA), nor as a function of the results of the 1st vs the 2nd night of recording. Nor was any significant difference in NP and PB found when comparing control vs sibling babies within each age group for the 1st or for the 2nd night of recording. In SIDS siblings, there was a significant decrease in the three variables studied between the 1st and the 2nd month of life. No significant decrease was found in controls. We conclude that SIDS siblings are not different from controls of the same age when respiratory variables are studied by CPG recordings.
Are polygraphic and cardiopneumographic respiratory patterns useful tools for predicting the risk for sudden infant death syndrome? A 10-year study.
Between 1974 and 1984 we have studied 204 control infants (C) comparing them with 650 SIDS siblings (SS) and 146 near-miss for SIDS (NM). These 1,000 full-term infants were recorded by day polysomnography (DPSG; n = 417), night polysomnography (NPSG; n = 257) and cardiopneumography (CPG; n = 2,600). Records were visually analyzed. In DPSG and NPSG, total amount of central, mixed and obstructive apnea as well as the percentage of periodic breathing was studied in each sleep state (active sleep, AS; quiet sleep, QS; indeterminate sleep, IS, and total sleep, TS) and over the total recording time (TRT). In CPG, only the total amount of central apnea and percentage of periodic breathing over TRT were studied. Infants were grouped according to postnatal age: less than 5, greater than or equal to 5 to less than or equal to 13, and greater than 13 to less than or equal to 26 weeks. In each age group results were compared as follows: C vs. SS, C vs. NM, and SS vs. NM for each parameter studied. Before 5 weeks and after 13 weeks there was no significant difference between C and SS, C and NM, and SS and NM in DPSG and NPSG for all categories of central, mixed and obstructive apnea as well as the percentage of periodic breathing in different sleep states and over TRT. Similar results were obtained in CPG for all categories of central apnea and percentage of periodic breathing over TRT.(ABSTRACT TRUNCATED AT 250 WORDS)
Structures of liposome membranes as models for similar features of cytoplasmic membranes of bacteria.
To characterize a special kind of membrane structure, visible in the cytoplasmic membranes of a Streptomyces hygroscopicus strain, liposome membranes were prepared from their extracted lipid mixture and from their lipid fractions (phospholipids, glycolipids, neutral lipids) and investigated by freeze-fracture electron microscopy. Liposome membranes made of the extracted lipid mixture reveal this special membrane structure, named wafer structure, from its regular pattern of bulges (30-40 nm in diameter). That is the proof that this membrane feature is a lipid structure. Liposome membranes prepared from the lipid fractions show the wafer structure if they are made of the phospholipid fraction only or in combination of this fraction with one or both of the other lipid fractions, indicating that wafer structure formation is primarily connected with the phospholipid content of the membranes. The glycolipid- and neutral lipid fractions amplify this phospholipid structure only. Additional to the wafer structure a raspberry structure with bulges of 55-65 nm in diameter is visible in some case. Obviously both structures are related.
Assessment of salt use at the table: comparison of observed and reported behavior.
Observations were made of salt added during meals. Nineteen per cent of 211 participants salted before tasting food, 18 per cent salted after tasting, and 2 per cent salted both before and after tasting. Of those who self-reported "never" to salt food before tasting, 6 per cent were observed to do so. Of those who reported never to salt after tasting, 3 per cent did so. Results support the conclusion that self-reported abstinence from use of table salt is strongly correlated with actual behavior.
A critical comparison of the history of sudden-death infants and infants hospitalised for near-miss for SIDS.
To determine whether significant historical differences distinguish the near-miss for Sudden Infant Death from the infants who died of SIDS, we analysed the histories and clinical data from two groups of infants seen in our University Hospital and from collaborative research group. The data were obtained with the use of a standardised questionnaire and consultation of all available medical data. Sixty-five infants were identified as near-miss for SIDS after they had suffered a severe cardiorespiratory incident during sleep for which no cause could be found despite a complete medical examination. After an autopsy had failed to reveal a cause for the unexpected death 95 cases of SIDS were retained in the study. A series of 353 variables were collected from the parents, the gynaecologists, neonatologists and attending physicians. After statistical analysis, only 15 of the 353 items studied significantly differentiated between the two groups. A step-wise discriminant analysis performed on these items led to the identification of six independent variables: the time of the incident; the circumstances leading to the observation of the child; the child's sleep position; previous minor intestinal problems; the size of the family and the mother's coffee consumption. Most variables indicate that the near-miss infants were discovered and rescued earlier than the infants who died. No other historical information appeared significantly to differentiate between the two groups of infants. These data need confirmation from a prospective epidemiological survey.
[Diagnoses to consider in newborn infants with inactive EEG tracings].
Thirty-one neonates without any electroencephalographic activity detectable on the first EEG before day 5 were studied. In the first group (20 neonates) the first EEG was performed on day 0. Signs of foetal and/or perinatal anoxia were observed. In the second group (11 neonates), the first EEG was performed between day 1 and day 4. In 7 cases, the neonate was considered normal during a period varying between a few hours and a few days. Various aetiologies other than foetal or perinatal anoxia were found: cardiac arrest, metabolic disease, polycystic encephalomalacia.
Exploring the potential of computer-assisted medical illustration.
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Respiratory pauses in normal infants and in siblings of victims of the sudden infant death syndrome.
Sleep polygraphic recording was carried out on 57 normal infants and on 100 SIDS siblings during morning naps between birth and the 4th month of life. Total sleep time and duration of sleep stages were determined. Central apnoeas of 2 sec and longer duration were analysed in AS, QS and IS. Apnoea index and number of apnoeas per 100 min of sleep stage were determined. Obstructive and mixed apnoeas were tabulated separately. Percentage of periodic breathing was also determined. Control babies and SIDS siblings were compared on these parameters, using the Mann-Whitney test. Between the 6th and 13th weeks of life respiratory pauses were significantly more frequent in SIDS siblings than in control subjects. The difference disappeared after the 13th week. The roles that peripheral afferents and the circadian organization of respiratory pauses play in determining the results are discussed. This technique does not appear to permit estimation of the risk of subsequent apnoeic episodes.
[EEG appearance during waking and falling asleep in children aged 1-4 years (without serious pathology)(author's transl)].
The authors have studied the EEG characteristics of 188 children aged 1-4, without serious pathology, during waking and falling asleep spontaneously in the afternoon. The children were divided into 3 groups: aged 12-23 months, 24-35 months and 36-47 months. On falling asleep the EEG appearances varied, but hypersynchrony was most marked in the youngest children and in the older group theta activity was commonest. Only 3 of the 188 children had runs of paroxysmal activity on falling asleep. The waking study again showed appearances governed by the patients' age with respect to 7 c/sec activity on provoked waking, but the appearances were more diverse on spontaneous waking and anterior theta activity only occurred in the oldest children. In general, a relation appeared to exist between the EEG appearance on falling asleep and on waking, in the respect that children falling asleep without hypersynchrony never wake up with it.
[Neonatal status epilepticus of unknown etiology (author's transl)].
Forty-three neonates with status epilepticus of unidentified etiology were studied by EEG. 90% had favorable outcome. In the cases with unfavorable evolution the following criteria allowed an early poor prognosis: a very early onset of the seizures in the first or second day of life, the presence of tonic seizures and hypertony between seizures, duration of the seizures more than 4 days, EEG activity in the frequency of the alpha band during the seizures, a flat tracing after the seizures, very discontinuous activity between the seizures and, finally, the reappearance of seizures after a seizure-free interval. In the cases of favorable outcome, an EEG follow-up is necessary: in 10% of these cases focal spikes appeared after 2 years without seizures. The necessity of prolonged anti-comital treatment is discussed.
Clinical and EEG study of 50 cases of neonatal hydrocephalus.
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Value of the EEG in acute intoxications in children.
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[Attempted differential diagnosis of tremor and clonus in newborns and other infants].
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[E.E.G. and neonatal hydrocephalus: record of 50 cases].
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