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Biomedical subjects

J L Lorenzo

Publications and source records attributed to J L Lorenzo.

8 recordsLinked to original sources
PubMed2004

Interrater reliability between scorers from eight European sleep laboratories in subjects with different sleep disorders.

Interrater variability of sleep stage scorings is a well-known phenomenon. The SIESTA project offered the opportunity to analyse interrater reliability (IRR) between experienced scorers from eight European sleep laboratories within a large sample of patients with different (sleep) disorders: depression, general anxiety disorder with and without non-organic insomnia, Parkinson's disease, period limb movements in sleep and sleep apnoea. The results were based on 196 recordings from 98 patients (73 males: 52.3 +/- 12.1 years and 25 females: 49.5 +/- 11.9 years) for which two independent expert scorings from two different laboratories were available. Cohen's kappa was used to evaluate the IRR on the basis of epochs and intraclass correlation was used to analyse the agreement on quantitative sleep parameters. The overall level of agreement when five different stages were distinguished was kappa = 0.6816 (76.8%), which in terms of kappa reflects a 'substantial' agreement (Landis and Koch, 1977). For different groups of patients kappa values varied from 0.6138 (Parkinson's disease) to 0.8176 (generalized anxiety disorder). With regard to (sleep) stages, the IRR was highest for rapid eye movement (REM), followed by Wake, slow-wave sleep (SWS), non-rapid eye movement 2 (NREM2) and NREM1. The results of regression analysis showed that age and sex only had a statistically significant effect on kappa when the (sleep) stages are considered separately. For NREM2 and SWS a statistically significant decrease of IRR with age has been observed and the IRR for SWS was lower for males than for females. These variations of IRR most probably reflect changes of the sleep electroencephalography (EEG) with age and gender.

Female↗
PubMed2002

Proof of safety of drugs: focus on vigilance.

It is well accepted that all new compounds, before administration to patients, should undergo safety evaluations in healthy subjects, including central nervous system (CNS) toxicity and as such the assessment of vigilance effects a relevant hallmark. The original concept of vigilance as a phenomenon observed only under conditions of monotony and signal regularity is increasingly falling into disfavor, embracing at present a much broader spectrum of behavior. Currently, vigilance may be regarded as a "readiness to adopt the appropriate behavior in a given situation, which thus finds outward expression through the quality and quantity of the behavior occurring in response to a given (internal or external) stimulus situation". The assumption that vigilance is a multifactorial phenomenon and not merely EEG data should be taken into account in order to study it accurately. Specifically, in drug research, apart from subjective reports and psychomotor performance tests, neurophysiological evaluations are regularly used such as Multiple Sleep Latency Test, Vigilance Epoch Classification or Parameters within a continuous scale. Although with limitations, temporal patterns of changes in activity of different frequency bands, indexes as the alpha slow-wave or the alpha anteriorization, computed from the EEG quantification, yielded different definitions of the intermediate states of the transition from wakefulness to sleep through the so-called subvigil stages. Spatial patterns are less documented. The recently proposed mathematical models to explain and predict variations in alertness are presented. Examples of the effects of different classes of drugs with the methods reported and its theoretical and practical relevance to vigilance research are introduced.

Arousal↗
PubMed2001

A short hypoosmotic swelling test for the prediction of boar sperm fertility.

This study was designed to explore the relationship between the ejaculate response to a hypoosmotic swelling test (HOST) and in vivo fertility in a group of 38 boars The hypoosmotic test used was a modification of the HOST that involves a shorter incubation time (5 vs 120 min) and lower osmotic pressure (75 vs 150 mOsm/kg). Ejaculates containing less than 20% abnormal spermatozoa were selected and checked for percentage of motility, percentage of normal acrosomes, percentage of short ORT and percentage of cells showing positive short HOST (sHOST) results Two hundred eightyeight sows were inseminated to obtain in vivo fertility and prolificacy data. No differences were shown between technicians in the sHOST results obtained. Significant differences were recorded between boars in sHOST results (p < 0.002). Only the sHOST result presented a significant correlation with in vivo fertility (r = 0.43, p < 0.01). Short HOST data significantly improved fertility prediction of routine semen analysis tests. Unlike motility and acrosomal status, sHOST values showed a significant decrease when fresh ejaculates (37 degrees C) were stored for 24 h at 15 degrees C, indicating possible damage due to cold shock.

Acrosome↗
PubMed1998

The anterior inferior cerebellar artery infarcts: a clinical-magnetic resonance imaging study.

Acute infarcts of the anterior inferior cerebellar artery (AICA) are unusual. We report 15 cases of AICA infarcts and their correlation with the topography of the lesion by brain MRI. During 2 years we prospectively identified 7 cases of AICA infarcts among 770 acute strokes (0.9% of the acute strokes seen in our department). We studied these cases and also another 8 that we found retrospectively. Most patients (8/15) had a unilateral affectation of both middle cerebellar peduncle (MCP) and inferior lateral pontine area (ILP), in these cases the main symptoms were vertigo, ataxia, peripheral facial palsy and hypoacusia. Two other patients had isolated MCP infarcts and were characterized by peripheral vertigo and ataxia, without hypoacusia or facial palsy. Another 2 patients had isolated ILP territory infarct characterized by vertigo, left peripheral facial palsy without hypoacusia and mild or no ataxia. One patient had a Gasperini syndrome. Finally 3 patients had bilateral AICA infarcts due to basilar thrombosis. The etiology was atherosclerosis in 9 patients, lacunar due to hypertension in 1, cardiac embolism in 1, migraine in 1 and unknown in 3. Among the 15 patients only 2 died, both with AICA plus infarcts. In the remaining patients a follow-up during a mean of 31 months (3 months to 12 years) showed no recurrences.

Adult↗
PubMed1997

Urodynamically based modification of Mitrofanoff procedure.

This paper reviews our experience with the Mitrofanoff principle as applied in eight patients. Of four patients with post-traumatic urethral stricture, three required the appendix as continent catheterizable conduit, with a modified appendicovesical anastomosis technique-that is, without a submucosal tunnel- and in one patient, the remnant ureter of a previous simple nephrectomy was used. Of the four remaining patients, one with a hypotonic bladder and three with urethral stricture, a complete laparoscopic approach was used to perform the same modified Mitrofanoff procedure with the appendix. With a mean follow-up of 19.5 months, all patients were completely dry. Only three patients had persistently positive urine cultures, but without evidence of renal function impairment. The modified direct appendicovesical anastomosis technique reduces the operative time, has a lower complication rate, and allows us to use a laparoscopic approach with the resulting benefits of a minimally invasive surgical procedure. As shown in urodynamic tests, urinary continence is preserved.

Adolescent↗
PubMed1987

Regulation of low density lipoprotein metabolism by 26-hydroxycholesterol in human fibroblasts.

Oxygenated derivatives of cholesterol are believed to play a role in cellular cholesterol homeostasis through the feed-back control of its biosynthesis. We report that 26-hydroxycholesterol inhibits the specific binding, uptake and degradation of 125I-LDL in human fibroblasts. The effect is dose-dependent, and saturation kinetics indicates a reduction of LDL-binding sites with no effect on ligand affinity. The results support a possible role of 26-hydroxycholesterol, a physiological oxysterol, in the regulation of cellular cholesterol homeostasis.

Cells, Cultured↗
PubMedDate not supplied

[Monoaminergic selectivity of the antidepressive drugs and sleep: neurophysiological implications of depression].

OBJECTIVES: To obtain better understanding of the neurophysiology of sleep and of depression, together with any relationship there might be between them. DEVELOPMENT: We review the mechanisms of action of the neurotransmitters involved in the sleep-waking cycle, and also the antidepressive drugs, concentrating on those with more selective mechanisms of action, and the selective serotonin re-uptake inhibitors. CONCLUSIONS: It is well know that the disorders associated with sleep play a predominant part in the symptoms of depressed patients, and these may revert with antidepressant treatment. Antidepressants cause, often markedly, changes in the characteristics of sleep at the same time as they improve the depressive symptoms. Thus, knowing the basis of the mode of action of antidepressive drugs, not only does the understanding of the neurophysiology of sleep progress, but also the understanding of sleep.

Arousal↗