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Biomedical subjects

M Albani

Publications and source records attributed to M Albani.

At least 37 records · Page 2Linked to original sources
PubMed1988

Are there tests predictive for prolonged apnoea and SIDS? A review of epidemiological and functional studies.

Sudden infant death syndrome (SIDS) remains the predominant cause of postneonatal mortality. Epidemiological studies have led to the definition of populations with an increased risk for SIDS: subsequent siblings of SIDS victims, infants with near miss for SID episodes, prematurely born infants with perinatal risk factors, and infants of drug dependent mothers. Furthermore, a variety of additional although rarely independent factors regarding both mothers and infants have been found to be associated with an increased risk for SIDS. Despite of this, the majority of infants still dying from SIDS do not belong to one or more of these risk groups and even within a group considered to be at increased risk it is impossible so far to identify individual infants at highest risk on the basis of an infant's history and clinical data. Therefore, different methods have been applied during the last several years in order to detect functional abnormalities of cardiorespiratory control during sleep with the aim of obtaining more specific and sensitive predictors of subsequent severe apnoea and SIDS. In an attempt to evaluate the predictive power of these various methods the present article reviews their results in relation to the follow up data of the infants under study. The results of the meanwhile innumerous studies were found to be at variance and often controversial. At the present time, none of these tests may be looked at as virtually improving our ability to predict the risk for prolonged apnoea and SIDS. One of the reasons for this may be the lack of standardisation of the particular methods with respect to both definition of study groups and conditions of testing infants. Since all of these tests have mainly been performed in infants of epidemiological risk groups, the definition of which is an indispensable prerequisite for the evaluation of both the indication and the results of such tests, an updated survey of the more recent epidemiological studies is given as an introduction.

Apnea↗
PubMed1987

Transcutaneous blood gases and sleep apnea profile in healthy preterm infants during early infancy.

Studying the development of transcutaneous blood gas levels (tcpO2 and tcpCO2) and the sleep apnea profile in relation to sleep states in normal preterm infants between 36 and 52 weeks postconceptual age we found a dynamic increase in tcpO2 during regular breathing (without apnea) and a steady decrease in tcpCO2 during both regular and periodic breathing. The mean tcpO2 of periodic breathing, however, persistently remained well below the corresponding level found during regular breathing. It is suggested that in normal preterm infants there is a continued maturational adjustment of autonomic respiratory control up to 3 months post term and, furthermore, that periodic breathing may persistently be associated with a relative hypoxemia.

Blood Gas Monitoring, Transcutaneous↗
PubMed1986

Sural nerve biopsy studies in Leigh's subacute necrotizing encephalomyelopathy.

Peripheral neuropathy marked by reduced nerve conduction velocities was found in four unrelated children, between the ages of 15 months and 9 years, whose autopsies revealed Leigh's subacute necrotizing encephalomyelopathy. Sural nerve biopsies disclosed primary demyelination and remyelination, as well as loss of myelinated and unmyelinated axons. The use of morphometric and electron microscopic studies shows that these techniques may reveal peripheral neuropathy in Leigh's disease more often than light microscopic methods alone.

Biopsy↗
PubMed1986

[Home monitoring of apnea in children at increased risk for sudden infant death (SIDS)].

Since 1981, 96 infants considered at increased risk of SIDS underwent home monitoring for prolonged sleep apnea: 23 infants after a near miss for SIDS event, 28 siblings of a SIDS victim and 45 infants with a variety of perinatal risk factors. For a total of 65 infants the course of home monitor surveillance was completed by September 1984 with a duration ranging from 6 to 15 month: 26% (4/15) of the near miss for SIDS group, 23% (3/13) of the SIDS siblings and 13% (5/37) of the perinatal risk cases developed more than one prolonged apneic episode with additional symptoms requiring vigorous intervention by parents. Two infants of the perinatal risk group became SIDS victims: despite an apnea alarm after 15 seconds the parents were unable to resuscitate their infant in one case, the other died from SIDS about 4 month after monitoring was discontinued because of an uneventful course and normal polygraphic sleep recordings The large number of prolonged apneas requiring intervention and the two SIDS cases (3% of the total study group) indicate a considerably increased risk of prolonged life-threatening sleep apnea and SIDS in the population monitored.

Diseases in Twins↗
PubMed1985

Infant sleep apnea profile: preterm vs. term infants.

By means of polygraphic sleep recording, the sleep apnea profile with respect to the number and duration of inactive, obstructive and mixed apneic episodes as well as periodic breathing has been investigated in infants born preterm at 40, 52 and 64 weeks conceptional age and compared to that of term infants. At 40 weeks preterm infants showed significantly more apnea and periodic breathing compared to term infants. The difference was essentially due to obstructive and mixed apnea in non-REM sleep. There was a sharp decrease in all apneic variables--inactive, obstructive and mixed apnea as well as of periodic breathing--at 52 weeks conceptional age in infants that were previously preterm. Both groups exhibited a rather identical sleep apnea profile at 64 weeks. Two prospectively studied infants in the preterm group later became SIDS victims. One of them might have been identified as being at risk on the basis of his apnea profile compared to the normative data now available.

Electroencephalography↗
PubMed1985

Physiological properties and pattern of innervation of regenerated muscles in the rat.

The regeneration of fast and slow muscles was compared following "mincing" and replacement into their own or alien muscle bed. At intervals varying from 2 to 9 weeks the tension developed by the regenerated muscles was assessed and compared to that developed by the muscles from the contralateral unoperated side. This parameter was then taken as an indication of recovery. The regenerated muscles never developed more than half of the tension of the control muscles. Muscles regenerated in the bed of extensor digitorum longus became fast-twitch muscles and muscles regenerated in the bed of soleus became slow-twitch muscles, no matter whether they originated from an extensor digitorum longus or soleus "mince". The regeneration of the muscle tissue in the place of extensor digitorum longus developed better than in the place of soleus. The pattern of innervation of the regenerated muscles was analysed using a combined cholinesterase silver stain. Many of the regenerated fibres had more than one end plate and some end plates more than one axon terminal. These results show that in adult animals muscle redevelopment can occur, but only to a limited extent. Moreover, on reinnervation of regenerated muscle fibres the axons do not assume their original pattern of innervation.

Animals↗
PubMed1985

Sleep apnoea profile in preterm infants recovering from respiratory distress syndrome.

Polygraphic recordings were made on 10 preterm infants recovering from respiratory distress syndrome and 12 healthy preterm control infants at 40, 52, and 64 weeks' conceptual age to study the influence of respiratory distress syndrome on the development of the sleep apnoea profile. Two significant differences were found: infants with respiratory distress syndrome not only had a lower incidence of non-obstructive apnoea and periodic breathing at 40 weeks but also a persistently higher incidence of obstructive and mixed apnoea at 52 and 64 weeks' conceptual age; the latter finding being related to non-rapid eye movement sleep only. While the lower incidence of both types of apnoea at 40 weeks suggests an advanced maturation of respiratory drive, the persistence of obstructive and mixed apnoea related to non-rapid eye movement sleep may reflect the impact of respiratory distress syndrome on airway structures.

Humans↗
PubMed1983

Oral phenytoin in infancy: dose requirement, absorption, and elimination.

Oral phenytoin therapy in infants required unexpectedly high doses of about 18 mg/kg body weight to achieve and to maintain serum concentrations between 8 and 25 micrograms/ml. Plasma half-life determined in 12 infants aged 6 weeks to 12 months ranged between 7.9 to 24.9 hours (mean 12.8 +/- 3.6 hours). Measurement of phenytoin metabolite excretion in urine during steady state revealed that only about 30% of the daily given phenytoin is eliminated through the kidneys. Studying the bioavailability of phenytoin in different age groups (infants, children, and adolescents) before and after ingestion of age-appropriate food showed an age-dependent absorption rate and extent, and an influence of the food upon the absorption pattern could be demonstrated. Mechanisms for this phenomenon of an impaired bioavailability of phenytoin in infancy are discussed.

Adolescent↗
PubMed1982

A familial progressive neurodegenerative disease with 2-oxoglutaric aciduria.

A boy and a girl born to a consanguineous Tunisian couple are suffering from a slowly progressive nervous disorder. Initially they both had normal psychomotor development with acquisition of gait and speech. First symptoms in the boy were athetoid movements during the second year of life. He later lost all motor and language skills and developed muscular rigidity and intention tremor. At the age of five years, he was completely bedridden while he appeared mentally much less affected. His younger sister followed a similar course. The major specific abnormality detected was a strikingly elevated excretion of 2-oxoglutaric acid, which was identified by gas liquid chromatography, mass spectrometry, and enzymatic analysis. 2-oxoglutarate dehydrogenase activity in homogenates of cultured skin fibroblasts was reduced to about 25% of control values in both children. Although the pathogenetic mechanisms leading to brain damage remain obscure, the finding strongly suggest an autosomal recessive neurometabolic disease with predominant involvement of the extrapyramidal system.

Basal Ganglia Diseases↗
PubMed1982

Neuronal control of neonatal respiration - sleep apnea and the sudden infant death syndrome.

During the last decade evidence has been accumulated that there might be a continuum from normally occurring short spells of apnea during sleep to life threatening long lasting respiratory pauses with marked bradycardia or even cardiac arrest from which, however, the infant could be resuscitated - the so-called Near Miss for Sudden Infant Death Event - and finally, to the Sudden Infant Death Syndrome (SIDS). There are still many missing links between these three phenomena and it seems likely that the connection between all three is not a straight matter in degree of immature dysfunction of cardiorespiratory control mechanisms. However, no other concept has shead so much light on SIDS and - most probably - no other concept with its consequence of continuous home monitoring has already salvaged so many babies as research into the different sleep apnea syndromes during infancy. However, for the final evaluation of the above mentioned hypothesis two issues urgently need clarification: a) How much apnea is normal at different ages and in different risk groups of infants. b) Can "near miss infants" or future victims of SIDS be identified on the basis of the amount of apnea prior to the event. In the first part of this survey brain mechanisms possibly underlying both, sleep apnea and serious apneic events will be discussed. In the second part new normative data on the amount of apnea will be presented together with 2 extraordinary cases who could be studied by means of longterm polygraphic sleep recordings prior to a definitely serious near miss event in one case and a crib death in another.

Brain Stem↗
PubMed1981

On the role of ribosylthymine in prokaryotic tRNA function.

tRNAPhe and tRNALys were isolated from an Escherichia coli K12 mutant deficient in ribosylthymine (rT) and from the wild-type strain. The sequence G-rT-psi-C which is common to loop IV of practically all tRNAs used in the elongation cycle of protein synthesis reads G-U-psi-C in the tRNAs of the mutant strain. The purified tRNAs were compared in various steps of protein biosynthesis. The poly(U)-dependent poly(Phe) synthesis performed with purified Phe-tRNAPhe and purified elongation factors showed no dependence on the presence or absence of ribosylthymine in the respective tRNAs. In contrast, the corresponding poly(A)-dependent poly(Lys) synthesis was markedly increased when Lys-tRNALys lacking rT was used. The analysis of individual functional steps of the poly(A)-dependent elongation cycle demonstrated that the absence of rT reduced the binding to the A-site and improved the translocation reaction, whereas the formation of the ternary complex EF-Tu . GTP . aa-tRNA as well as both tRNA binding to the P-site and the peptidyltransferase reaction remained unaffected. The presence of U in place of rT in tRNA increases the misincorporation of leucine in an optimized poly(U)/poly(Phe) system from about 3 in 10 000 to 3 in 1000. Our results are in agreement with the view that rT is involved in tRNA binding to the A-site in contrast to the P-site, and suggested that the presence of rT in tRNA improves the fidelity of the decoding process at the A-site of the ribosome.

Bacterial Proteins↗
PubMed1980

Sleep induced PO2-changes in preterm infants.

In seven healthy preterm infants the transcutaneous PO2 was measured during different sleep states. The tcPO2 is lower during active sleep than during quiet sleep and shows a higher variability in active sleep. The incidence of apneic spells, which occur predominantly during active sleep, was not found to be correlated to tcPO2 levels.

Apnea↗
PubMed1980

Circulating haematopoietic stem cells (CFUc) in healthy and diseased pre-term infants.

During fetal life, haematopoiesis is in a physiologic state of rapid expansion. The activity of the pluripotent haematopoietic stem cell compartment of the bone marrow probably is reflected by the number and proliferative potentiality of CFUc in the blood circulation. We have studied, by the methylcellulose culture technique and without addition of exogenous colony stimulating factor (CSF), blood CFUc in pre-term and full-term newborn infants, in full-term infants 10 to 17 d of age, and in adults. Two groups of pre-term infants were studied: otherwise healthy infants and sick infants, including infants small-for-date and in perinatal distress. In healthy pre-term infants and in full-term infants 147 +/- 25 (SD) and 105 +/- 41 (SD) colonies per 100 000 lymphoid cells were formed, respectively. This is clear evidence for the presence in the blood of both. CFUc and CSF producing cells. By contrast, there was no or only slight spontaneous colony formation by sick pre-term infants, by older infants, and by adult.

Adult↗
PubMed1979

Role of ribothymidine in the thermal stability of transfer RNA as monitored by proton magnetic resonance.

In order to elucidate the functional role of the modified uridines at position 54 of tRNA, the 270 MHz high-field proton NMR spectra of methionine tRNAs from E. coli, from a mutant thereof, and from T. thermophilus, containing ribothymidine, uridine and 2-thioribothymidine, respectively, have been measured as a function of temperature. A comparison of the NMR melting profiles of the minor nucleosides from these tRNAs shows that the melting temperature of uridine containing tRNA is 6 degrees C lower than that of the wild type tRNA whereas that of the 2-thioribothymidine tRNA is 7 degrees C higher than that of the wild type tRNA. These results, therefore, demonstrate that these modifications serve for stabilization of the tertiary structure of tRNA.

Drug Stability↗
PubMed1979

[Atresia of the larynx, a rare cause of postnatal respiratory distress (author's transl)].

An infraglottic atresia of the larynx with normally developed vocal cords necessitated postnatally an emergency tracheotomy after intubation attempts had failed. Laryngeal atresia is a very rare malformation. As in our example, it is in most cases accompanied by a tracheo-hypopharyngeal fistula which has to be interpreted ontogenetically. The survival chances of the newborn with this malformation are generally very poor.

Autopsy↗