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Biomedical subjects

R Pelayo

Publications and source records attributed to R Pelayo.

At least 19 recordsLinked to original sources
PubMed2006

Baseline MRI predicts future attacks and disability in clinically isolated syndromes.

OBJECTIVE: To determine the relation between baseline MRI and both conversion to multiple sclerosis (MS) and development of disability in a cohort of patients with clinically isolated syndromes (CIS). METHODS: From 1995 to 1998, 175 consecutive patients with CIS underwent brain MRI within 3 months of their first attack and again 12 months and 5 years later. We studied the number and location of lesions at baseline and development of new T2 lesions. We also analyzed conversion to MS and development of disability (Expanded Disability Status Scale [EDSS] > or = 3.0). RESULTS: We included 156 patients with CIS followed for a median of 7 years. Compared to the reference group with 0 Barkhof criteria at baseline MRI, patients with one or two Barkhof criteria showed an adjusted hazard ratio (HR) of 6.1 (2.2 to 16.6) and patients with three to four Barkhof criteria of 17.0 (6.7 to 43) for conversion to MS and differentiated patients with low, medium, and high conversion risk. EDSS at year 5 correlated with baseline number of Barkhof criteria (r = 0.46, p < 0.0001). When categorizing by number of baseline lesions, similar results were seen. Patients with a baseline MRI with three to four Barkhof criteria had an adjusted HR of 3.9 (1.1 to 13.6) for reaching EDSS > or = 3.0. Only 10% of the latter had disability at year 5, but 40% reached this at 8 years. CONCLUSIONS: Baseline MRI determines the risk for converting to clinically definite multiple sclerosis and correlates with disability at 5 years. The proportion of patients developing disability is low during the first 5 years but rapidly increases shortly after.

Adult↗
PubMed2001

Sleep-disordered breathing and upper-airway anomalies in first-degree relatives of ALTE children.

From 1985 through 1995, 348 infants aged 3 wk-3 mo were referred to the Stanford Sleep Clinic for "apparent life-threatening events" (ALTE). A small group of 48 infants with no history of sleep-disordered breathing (SDB) was also recruited and used as controls (they comprised group C). We conducted a systematic investigation of relatives (parents, siblings, and grandparents) of the infants, including a clinical evaluation, craniofacial investigation, and the completion of an extensive (189-question) validated sleep/wake questionnaire. All data were calculated before the subdivision of ALTE infants into two groups. The subdivision was based on a blind scoring of the infants' polygraphic recordings; 42.5% of the infants were negative for SDB (Group A), whereas 57.5% of the infants were positive for SDB (Group B). Groups A and C were not significantly different from each other. Forty-three percent of the relatives of Group B infants had been treated for SDB (with nasal CPAP, surgical or dental appliance treatments) compared with 7.1% of Group A relatives. Clinical investigation indicated a significantly higher presence of small upper airways in the families of infants with SDB. About twice as many relatives reported the presence of asthma in Group B compared with Group A. Naso-oro-maxillomandibular anatomic traits that may lead to small upper airways in parents may be risk factors for abnormal breathing during sleep in their infants.

Case-Control Studies↗
PubMed2000

Apparent life-threatening events, facial dysmorphia and sleep-disordered breathing.

UNLABELLED: A standardized clinical evaluation and questionnaire was, beginning in 1985, applied to infants referred for an apparent life-threatening event (ALTE). All children who underwent this "core evaluation protocol" during a 10-year period were reviewed. Documentation of clinical complaints, symptoms and signs of sleep-disordered breathing, sleep/wake evaluation, systematic evaluation of the face and naso-oro-pharynx, nocturnal polygraphic recording, and systematic follow-up was conducted. A total of 346 infants had complete data sets, with a smaller group of 46 age-matched healthy infants as controls. A scorer blind to the clinical data analyzed the polygraphic investigation and divided the 346 referred into two groups. Group A, 42.6% of the population, included infants with no abnormal findings based on nocturnal polygraphic recording. These infants were no different from controls at initial evaluation and during follow-up. Group B, 57.4% of the population, included infants who had obstructive breathing during sleep which became more obvious over time. Two-thirds of these infants not only had clinical symptoms of sleep-disordered breathing but also had mild facial dysmorphia that could be seen clearly at 6 months of age. CONCLUSION: A subgroup of infants with apparent life-threatening events present an indication of a sleep-disordered breathing syndrome which is associated with a mild dysmorphia. This mild facial dysmorphia needs to be recognized early to distinguish these infants from other infants with apparent life-threatening events and to initiate appropriate treatment.

Facial Bones↗
PubMed1998

Narcolepsy in prepubertal children.

Narcolepsy was diagnosed in 51 children (29 boys). The age range was 2.1 to 11.8 years (mean, 7.9 +/- 3.1 years). A mean of three referrals was made before narcolepsy was considered. In 10 children, cataplexy was the presenting symptom. Thirty-eight children acknowledged sleep paralysis and 30 acknowledged hypnagogic hallucinations. All children had sleep studies; 31 exhibited rapid eye movement at sleep onset. The mean sleep latency was 1.5 minutes +/- 39 seconds on the Multiple Sleep Latency Test. All children had at least two sleep-onset rapid eye movement sleep episodes in this test. Forty-six children were HLA class II-positive for DQw6, and 45 were also positive for DRw15. Thirty (65%) families refused referrals to support and counseling groups. Teachers often refused to acknowledge a medical problem. During follow-up, all children presented at least once with depressive symptoms in reaction to their syndrome. Narcolepsy should be considered when evaluating children with behavioral and depressive symptoms.

Attitude to Health↗
PubMed1998

Sleep-disordered breathing in children.

The first series of children with obstructive sleep apnoea syndrome was reported in 1976. Later it became apparent that children may have breathing disorders during sleep without frank apnoea or 'hypopnoeas'. This pattern could be detected by measuring the oesophageal pressure. This led to the concept of sleep-disordered breathing as a spectrum that combines obstructive sleep apnoea syndrome and the upper airway resistance syndrome. Studies that do not take into account this spectrum may misclassify symptomatic patients as 'primary snorers'. The exact prevalence of sleep-disordered breathing in children is unknown but may be as high as 11%. There is a familial predisposition to sleep-disordered breathing. Nasal obstruction and mouth breathing influence facial growth, which may further lead to difficulty in breathing while asleep. Symptoms include an increase in total sleep time, nonspecific behavioural difficulties, hyperactivity, irritability, bed-wetting and morning headaches. Clinical signs include failure to thrive, increased respiratory effort with nasal flaring and suprasternal or intercostal retractions. Also, abnormal paradoxical inward motion of the chest may occur during sleep. Excessive daytime sleepiness and obesity are not always present. Untreated children may develop cardiovascular complications. The condition is treatable with continuous or bilevel positive airway pressure, and may be cured with surgery.

Airway Resistance↗
PubMed1997

Obstructive sleep apnea surgery: risk management and complications.

BACKGROUND: Hypoxemia, hypertension, airway obstruction, and death have been associated with surgery for obstructive sleep apnea syndrome (OSAS). Patient analysis was undertaken to identify potential factors that could affect risk-management outcome. METHODS: One hundred eighty-two consecutively treated patients with OSAS undergoing 210 procedures were evaluated. Fifty-four factors were analyzed. RESULTS: Group characteristics included a mean age of 48.2 years, a mean respiratory disturbance index of 42.3, and a mean low oxyhemoglobin desaturation (LSAT) of 77.5%. Surgery included a combination of uvulopalatopharyngoplasty (162 patients; 77%) and maxillofacial procedures (173 patients; 82%). Patients with a respiratory disturbance index greater than 40 and an LSAT less than 80% (117 patients; 64%) were maintained on nasal continuous positive airway pressure. Thirty-nine patients (18.6% had difficult intubations. There was a positive correlation (p > 0.001) of difficult intubations, neck circumference (> 45.6 cm) and skeletal deficiency (Sella-Nasion-Point B < 75 degrees). All tubes were removed with the patient awake in the operating room with two transient episodes of airway obstruction. One hundred forty-eight of the patients (70.5%) required postoperative intravenous antihypertensive medications. Patients with a preoperative history of hypertension had a significantly increased risk (p > 0.01) of requiring intraoperative and postoperative intravenous antihypertensive medications. The mean hospital stay was 2.2 days (SD +/- 0.9). Analgesia was achieved with intravenous morphine sulfate or meperidine HCl (intensive care unit) and oral oxycodone (non-intensive care unit). There were no significant oxyhemoglobin desaturations, irrespective of severity of OSAS or obesity (mean LSAT day 1, 94.8% (SD +/- 2.4); mean LSAT day 2, 95.5% (SD +/- 1.6)). Complications included postoperative bleeding (n = 4), infection (n = 5), seroma (n = 3), arrhythmia (n = 4), angina (n = 1), and loss of skeletal fixation (n = 1). CONCLUSION: Intraoperative airway risks can be reduced by use of fiberoptic intubation in patients with increased neck circumference and skeletal deficiency. Patients with OSAS are at a significantly increased risk for hypertension. Nasal continuous positive airway pressure eliminated the postoperative risk of hypoxemia, which allowed the use of adequate parenteral or oral analgesics.

Female↗
PubMed1996

Development of circadian rhythmicity of temperature in full-term normal infants.

Twelve full-term infants (7 girls and 5 boys) with normal neurological, behavioral and somatic development were followed at regular intervals during the first 5 months of life to appreciate the development of circadian rectal temperature rhythmicity. Activity and temperature (oral at birth, rectal thereafter) were monitored for a minimum of 60 hours on seven separate occasions: at birth, 3 weeks, 6 weeks, 8 weeks, 10 weeks, 16 weeks and 20 weeks of age. Activity was measured using an actigraph worn on the infant's wrist, and rectal temperature was measured using a rectal probe attached to a portable microprocessor (Vitalog TM). Data points were collected every 2 minutes. No fewer than ten infants were monitored at each session, and no infant missed more than one session. Missing recordings were due to equipment malfunctions, probe expulsions and minor health problems. Six infants out of 12 were successfully monitored at each of the first four sessions, from birth to 8 weeks of age inclusively, and two subjects were successfully monitored at all seven sessions. Periodic regression analysis was performed by least squares curve fit with secondary analysis of variance. Analysis of covariance was performed on repeated measures. There was no evidence of rectal temperature circadian rhythmicity at 3 weeks. Two infants demonstrated a circadian rhythmicity at 6 weeks, and all infants had a circadian rhythmicity at 10 weeks post-natal age. At the time of the first observance of circadian rhythmicity of rectal temperature, the mean delta in temperature from peak to trough was 0.6 +/- 0.3 degrees C. This delta was greater at the 16th week, with a mean value of 1.2 +/- 0.3 degrees C. The trough was seen during the first part of the long nocturnal inactivity period. Circadian rhythmicity of rectal temperature was always observed in the studied subjects before the establishment of a consolidated, long daytime wake period.

Body Temperature Regulation↗
PubMed1996

Recognition of sleep-disordered breathing in children.

OBJECTIVE: To determine whether upper airway resistance syndrome (UARS) can be recognized and distinguished from obstructive sleep apnea syndrome (OSAS) in prepubertal children based on clinical evaluations, and, in a subgroup of the population, to compare the efficacy of esophageal pressure (Pes) monitoring to that of transcutaneous carbon dioxide pressure (tcPCO2) and expired carbon dioxide (CO2) measurements in identifying UARS in children. STUDY DESIGN: A retrospective study was performed on children, 12 years and younger, seen at our clinic since 1985. Children with diagnoses of sleep-disordered breathing were drawn from our database and sorted by age and initial symptoms. Clinical findings, based on interviews and questionnaires, an orocraniofacial scale, and nocturnal polygraphic recordings were tabulated and compared. If the results of the first polygraphic recording were inconclusive, a second night's recording was performed with the addition of Pes monitoring. In addition, simultaneous measurements of tcPCO2 and endtidal CO2 with sampling through a catheter were performed on this second night in 76 children. These 76 recordings were used as our gold standard, because they were the most comprehensive. For this group, 1848 apneic events and 7040 abnormal respiratory events were identified based on airflow, thoracoabdominal effort, and Pes recordings. We then analyzed the simultaneously measured tcPCO2 and expired CO2 levels to ascertain their ability to identify these same events. RESULTS: The first night of polygraphic recording was inconclusive enough to warrant a second recording in 316 of 411 children. Children were identified as having either UARS (n = 259), OSAS (n = 83), or other sleep disorders (n = 69). Children with small triangular chins, retroposition of the mandible, steep mandibular plane, high hard palate, long oval-shaped face, or long soft palate were highly likely to have sleep-disordered breathing of some type. If large tonsils were associated with these features, OSAS was much more frequently noted than UARS. In the 76 gold standard children, Pes, tcPCO2, and expired CO2 measurements were in agreement for 1512 of the 1848 apneas and hypopneas that were analyzed. Of the 7040 upper airway resistance events, only 2314 events were consonant in all three measures. tcPCO2 identified only 33% of the increased respiratory events identified by Pes; expired CO2 identified only 53% of the same events. CONCLUSIONS: UARS is a subtle form of sleep-disordered breathing that leads to significant clinical symptoms and day and nighttime disturbances. When clinical symptoms suggest abnormal breathing during sleep but obstructive sleep apneas are not found, physicians may, mistakenly, assume an absence of breathing-related sleep problems. Symptoms and orocraniofacial information were not useful in distinguishing UARS from OSAS but were useful in distinguishing sleep-disordered breathing (UARS and OSAS) from other sleep disorders. The analysis of esophageal pressure patterns during sleep was the most revealing of the three techniques used for recognizing abnormal breathing patterns during sleep.

Airway Resistance↗
PubMed1995

Nondrug treatment trials in psychophysiologic insomnia.

BACKGROUND: Due to a variety of potential problems with long-term hypnotic use, patients and treating physicians often try to avoid drugs in the treatment of psychophysiologic insomnia and to use nondrug treatment strategies, but these treatments must bring relief within a limited amount of time to be acceptable to patients. METHOD: Thirty patients participated in the study. All had, for a minimum of 6 months, the complaint of less than 6 hours total sleep time per night in conjunction with either: (1) spending more than 30 minutes in bed before falling asleep, or (2) awakening during the night within 2 hours of sleep onset with difficulty returning to sleep. All subjects had the associated complaint of daytime impairment and none had used hypnotics for at least 3 months. Patients were randomly assigned to three parallel treatment groups: structured sleep hygiene, structured sleep hygiene with late afternoon moderate exercise, and structured sleep hygiene with early morning light therapy. Patients responded to questionnaires and filled out sleep logs. In addition, they underwent clinical evaluation, structured interviews, nocturnal monitoring, and actigraphy. The analyzed variables before and at the end of treatment were those derived from sleep logs and actigraphy. RESULTS: All subjects showed a trend toward improvement, independent of the treatment received, but only the "structured sleep hygiene with light treatment" showed statistically significant improvement at the end of the trial. CONCLUSIONS: Patients with chronic psychophysiologic insomnia may benefit from a nondrug treatment approach. Light therapy appears particularly promising.

Adult↗
PubMed1995

Home nasal continuous positive airway pressure in infants with sleep-disordered breathing.

OBJECTIVE: To review our experience with home nasal continuous positive airway pressure (CPAP) in infants with small upper airways and abnormal breathing during sleep. STUDY DESIGN: Seventy-four infants with sleep-disordered breathing and narrow upper airways, as identified by nocturnal polygraphic recording and endoscopic evaluation, were treated at home with nasal CPAP. Infants with craniofacial anomalies and trisomy 21, and infants who had been referred to us as having had "apparent life-threatening events," made up the majority of the population. Because of the rapid growth of infants, regular follow-up visits were scheduled to adjust CPAP and mask size. RESULTS: Seventy-two infants were successfully treated at home with nasal CPAP; there were two failures. Follow-up lasted from 5 months to 12 years. Compliance was not a problem, but home nasal CPAP was prescribed only for infants who lived close to our center and whose families and pediatricians were willing to support compliance. COMMENTS: Home nasal CPAP requires careful, in-laboratory titration and regular follow-up to adjust both pressure and mask size. With the support of families and pediatricians, home nasal CPAP can be an effective treatment for infants with upper airway respiratory problems during sleep. In many cases, it can provide an interim solution, enabling physicians to plan surgery at an appropriate time and giving infants time to grow before having to undergo surgical stress.

Airway Obstruction↗
PubMed1994

Progressively intractable seizures, focal alopecia, and hemimegalencephaly.

We report a 3-year-old boy with the neurocutaneous combination of unilateral alopecia, ipsilateral hemimegalencephaly, and intractable seizures. He was born with an asymmetric hair pattern consisting of absent patches of hair, a small left eyebrow, and less eyelashes on the left eye; he had normal development until age 17 months, when he experienced right focal seizures with fever. Two months later, fever triggered new seizures characterized by flurries of head and body flexion and adduction of the right arm. He had left hand preference and language regression. EEG manifested left hemihypsarrhythmia, and MRI showed left hemimegalencephaly with marked enlargement of the temporal lobe with ventriculomegaly. Seizures were refractory to treatment with phenobarbital, adrenocorticotropic hormone, pyridoxine, sodium valproate, clonazepam, carbamazepine, phenytoin, and felbamate. This may represent a previously undescribed neurocutaneous syndrome.

Alopecia↗
PubMed1992

Active protection of mice against Salmonella typhi by immunization with strain-specific porins.

NIH mice were immunized with between 2.5 and 30 micrograms of two highly purified porins, 34 kDa and 36 kDa, isolated from the virulent strain Salmonella typhi 9,12, Vi:d. Of mice immunized with 10 micrograms of porins, 90% were protected against a challenge with up to 500 LD50 (50% lethal doses) of S. typhi 9,12,Vi:d and only 30% protection was observed in mice immunized with the same dose of porins but challenged with the heterologous strain Salmonella typhimurium. These results demonstrate the utility of porins for the induction of a protective status against S. typhi in mice.

Animals↗
PubMed1990

[Seroepidemiology of amebiasis in the northern region of the Republic of Mexico].

The object of paper has been the study of amebic seroepidemiology in the northern region of Mexico, by means of an immunoenzymatic assay in solid phase (ELISA). The proteic antigen was obtained from axenic culture of E. histolytica's trophozoites of strain HM1:IMSS, by means of solubilization with phenoxy polyethoxyethanol (Triton X-100). Standardization of the method was obtained by analysis of 80 sera from patients with both a clinical and radiologic diagnosis of amebic hepatic abscess and 80 sera from healthy patients. The sensitivity reached 95% and the specificity was 90.7%. 15,457 sera from eight Mexican northern states were tested as part of the National Seroepidemiologic Survey. A semiautomatic BIOMEK 1,000 (Beckman Ins.) equipment was used. The positive ratio varied between 2.0% in Southern Baja California and 4.92% in Chihuahua, with an average ratio for the whole group of 3.34%. The first three places, in descending order, are Chihuahua (4.92%), Sinaloa (4.01%) and Northern Baja California (3.78%). The positive man: woman ratio was 0.87:1 and fluctuated between 0.38:1 in Coahuila and 1.76:1 in Nuevo Leon. In the whole sample the positive ratio of men was 3.00% and in women was 3.43%. The antibody profile related to age, is similar to diseases reported to be highly endemic; the percentage of positive sera rose progressively up to the age of 20 years (4.05%), at which a plateau occurred with a slight descending tendency up to 60 years of age (3.54%), after which a clear descent in the positive index is seen. No important variations were observed when comparing groups of ages and sexes. The antibody level seems to show an inverse relationship with the incidence rate of amebiasis.

Adolescent↗