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Biomedical subjects

R Peled

Publications and source records attributed to R Peled.

At least 19 recordsLinked to original sources
PubMed1997

Epidemiology of childhood tuberculosis in the Ashkelon region in Israel, 1958-1994.

The incidence rates of tuberculosis (TB) in Israel decreased steadily up to 1984, but rose again between 1985 and 1991, mainly due to immigration waves from Ethiopia. The epidemiology of TB in children was surveyed in the Ashkelon region. The regional TB register of Barzilai Medical Centre, kept since 1958, was used as the source for our data. Two hundred and fifty TB cases in children were reported between 1958 and 1994, constituting 9.7% of the total 2565 cases reported in the whole population of Israel's southern Mediterranean coast. While in the late 1950s and early 1960s the majority of reported cases occurred in children of North African origin, reflecting the large wave of immigration from North Africa at that time, in 1985-94 at the time of the Ethiopian immigration wave, Ethiopian children constituted the majority of the patients. They were diagnosed up to 9 years after arrival. None of the reported cases was HIV-positive.

Adolescent↗
PubMed1996

Reversible surface aggregation in pore formation by pardaxin.

The mechanism of leakage induced by surface active peptides is not yet fully understood. To gain insight into the molecular events underlying this process, the leakage induced by the peptide pardaxin from phosphatidylcholine/ phosphatidylserine/cholesterol large unilamellar vesicles was studied by monitoring the rate and extent of dye release and by theoretical modeling. The leakage occurred by an all-or-none mechanism: vesicles either leaked or retained all of their contents. We further developed a mathematical model that includes the assumption that certain peptides become incorporated into the vesicle bilayer and aggregate to form a pore. The current experimental results can be explained by the model only if the surface aggregation of the peptide is reversible. Considering this reversibility, the model can explain the final extents of calcein leakage for lipid/peptide ratios of > 2000:1 to 25:1 by assuming that only a fraction of the bound peptide forms pores consisting of M = 6 +/- 3 peptides. Interestingly, less leakage occurred at 43 degrees C, than at 30 degrees C, although peptide partitioning into the bilayer was enhanced upon elevation of the temperature. We deduced that the increased leakage at 30 degrees C was due to an increase in the extent of reversible surface aggregation at the lower temperature. Experiments employing fluorescein-labeled pardaxin demonstrated reversible aggregation of the peptide in suspension and within the membrane, and exchange of the peptide between liposomes. In summary, our experimental and theoretical results support reversible surface aggregation as the mechanism of pore formation by pardaxin.

Amino Acid Sequence↗
PubMed1996

Surgical treatment of sleep apnea syndrome.

Several surgical procedures have been developed for the treatment of sleep apnea syndrome. These include nasal, uvulopalatopharyngeal, and head and neck surgery, weight reduction surgery, and tracheostomy. Despite over 15 years of experience with some of these operations, there is still a lack of consensus regarding the indications, success rate, complications, and long-term prognosis associated with these procedures. The current status of these surgical procedures is reviewed.

Adult↗
PubMed1995

[Treatment of obstructive sleep apnea with anterior mandibular positioning device].

The efficacy of the anterior mandibular positioning (AMP) device in obstructive sleep apnea syndrome was assessed. This device advances the mandible anteriorly by approximately 5-7 mm. 29 patients were examined and questioned about temporomandibular (TM) and facial pain before and after treatment with the device. Polysomnographic sleep studies were performed on all before, and 2 weeks after continuous use of the AMP device. 10 of the patients also underwent polysomnographic follow-up after 1 year. The mean apnea index (AI) before treatment was 40.1, which decreased to 24.3 (p < 0.0001) after 14.3 days of treatment with the AMP device. O2 saturation also increased, from 84.2% before, to 89.2% after treatment (p < 0.002). In 10 patients the mean AI after 1 year was 24.9, not different from that after only 2 weeks of treatment, but significantly different from their mean AI before treatment (39.8). Use of the AMP device did not change blood saturation levels; neither did it affect dental status, action of the masticatory muscles, nor did it cause TM joint dysfunction. 21 patients (72.4%) have now been fitted with an AMP device, and the mean follow-up is 13.4 months (range 2-22); 3 have been using the AMP only intermittently for TM joint pain or discomfort. We conclude that the AMP device helps the majority of patients and is an alternative, nonsurgical method for treating obstructive sleep apnea syndrome.

Follow-Up Studies↗
PubMed1995

Melatonin improves evening napping.

Twelve young adults were treated with either melatonin, 3 mg or 6 mg, or placebo, at two different times before an early evening nap (18.00-20.00 h) according to a balanced double-blind Latin square design. Polysomnographic monitoring revealed that both dosages of melatonin significantly shortened sleep latency and increased total sleep time in comparison to placebo, irrespective of the time of administration. Subjects also tended to assess their sleep as 'deeper' after melatonin treatment. Based on previous data and the present results, it was concluded that exogenous melatonin exerts hypnotic effects only when circulating levels of endogenous melatonin are low.

Administration, Oral↗
PubMed1995

HLA class II analysis in Jewish Israeli narcoleptic patients.

HLA class II was investigated in eight Jewish narcoleptic patients, representing the total of such patients known in Israel at present, and in three patients suffering from sleep disturbances other than narcolepsy. All (11 out of 11) patients carried the serologic specificities DR2, DQ6 (DQ1). At the DNA level, all narcoleptics were found to be DRB1*1501, DQA1*0102, DQB1*0602 which indicates that the susceptibility gene may be located within the HLA class II region, DR, and/or DQ. As for the nonnarcoleptic patients with idiopathic hypersomnia, they carried different alleles of DR2 and DQ6, namely DRB1*1502, DQA1*0103, DQB1*0601. This study confirms that the incidence of narcolepsy in Israel is extremely low and that HLA class II genes or a gene(s) tightly linked to them are involved in the disease.

Alleles↗
PubMed1995

Mortality in sleep apnea patients: a multivariate analysis of risk factors.

During 1976-1988 we diagnosed sleep apnea syndrome (SAS) in 1,620 adult men and women monitored in the Technion sleep laboratories. Their age at the time of diagnosis ranged between 21 and 79 years. Fifty-seven patients (53 men and 4 women) had died by 1990, 53% due to respiratory-cardiovascular causes. The observed/expected (O/E) mortality rates, calculated for men only, revealed excess mortality of patients under 70 years old. Excess mortality was significant in the fourth and fifth decades (3.33, p < 0.002; 3.23, p < 0.0002, respectively). In patients older than 70 O/E was 0.33 (p < 0.0007). Hierarchical multivariate analysis with four fixed variables [age, body mass index (BMI), hypertension and apnea index] and four additional variables added manually one at a time (heart disease, lung disease, diabetes, apnea duration) was used to determine the predictors of death from all causes, cardiopulmonary causes and from myocardial infarction (MI). All four major variables were found to be significant predictors of mortality from all causes, in addition to lung disease and heart disease. Only age and BMI were significant predictors of cardiopulmonary deaths in addition to lung disease. Age, BMI and hypertension predicted MI deaths in addition to lung disease. These results were interpreted to suggest that SAS affects death indirectly, most probably by being a risk factor for hypertension.

Adult↗
PubMed1994

Recurrence of sleep apnea without concomitant weight increase 7.5 years after weight reduction surgery.

In this study we report on a long-term follow-up of 14 morbidly obese sleep apneic patients, 11 of whom were male and 3 female. The mean age was 46 +/- 8.5 years. These patients had undergone weight reduction surgery. Before surgery, body mass index (BMI) and apnea index (AI) were 45 +/- 7.2 kg/m2 and 40 +/- 28.8 (SD) h-1, respectively. Four and a half months after surgery (range, 2 to 7 months), both BMI and AI significantly decreased to 33 +/- 7.5 kg/m2 and 11 +/- 16.4 h-1, respectively. Seven and half years after surgery (range, 5 to 10 years), BMI increased only slightly to 35 +/- 6.0 kg/m2 (p > 0.2), while AI increased significantly to 24 +/- 23 h-1 (p < 0.05). There were poor and insignificant correlations between changes in BMI and AI prior to 4.5 months after operation (r = 0.23; p > 0.4). and 4.5 months to 7.5 years after operation (r = 0.41; p > 0.1). We conclude that morbid obesity is not the only causative factor in the sleep apnea syndrome for these patients. Weight reduction surgery alone does not "cure" their sleep apnea, and they are still at risk.

Adult↗
PubMed1993

[Ambulatory blood pressure in obstructive sleep apnea syndrome].

38 patients with obstructive sleep apnea syndrome underwent automated ambulatory 24-hour blood pressure monitoring. Systolic, diastolic and mean pressure values were significantly correlated with the apnea index (AI) during sleep, as well as during wakefulness. A significant negative correlation was found between minimal arterial O2 saturation in sleep and diastolic blood pressure values during waking hours. The contribution of the AI to blood pressure during sleep and wakefulness was significant, while the contribution of body mass index (BMI) was negligible. These results support the causal relationship between the severity of sleep apnea syndrome and systemic hypertension, independent of BMI.

Blood Pressure↗
PubMed1993

The relationship between the severity of sleep apnea syndrome and 24-h blood pressure values in patients with obstructive sleep apnea.

Automated ambulatory 24-h BP monitoring was made in 38 patients with obstructive sleep apnea syndrome. Stepwise multiple regression analysis revealed that diastolic, systolic, and mean BP values during sleep as well as during wakefulness were significantly related to apnea/hypopnea index and age. Minimal arterial O2 saturation and total sleep time also significantly contributed to diastolic and mean BP values during sleep. Body mass index did not significantly contribute to any of the BP values. These results support a causal relationship between the severity of sleep apnea syndrome and systemic hypertension.

Adult↗
PubMed1992

Bariatric surgery in morbidly obese sleep-apnea patients: short- and long-term follow-up.

Forty-seven obese sleep-apnea patients were investigated in the sleep laboratory before and after a massive weight reduction achieved by bariatric surgery. The first postoperative sleep investigations were performed approximately 1 y after surgery and revealed a highly significant decrease in the number of apneic episodes per hour of sleep and a significant improvement in all sleep-quality-related measures. A second postoperative sleep study was performed approximately 7 y postoperatively and revealed that regaining of weight was associated with the reappearance of sleep apnea syndrome, although the great majority of the patients still felt, subjectively, that they were well and did not suffer from recurrence of the sleep apnea syndrome.

Adult↗
PubMed1991

The value of sleep recording in evaluating somnambulism in young adults.

Somnambulism (SOM) is a benign childhood sleep disorder which may persist until young adulthood. The diagnosis relies heavily on the history, and no polysomnographic (PSG) criteria have yet been defined. The present study attempts to evaluate the role of whole-night polysomnographic recording in the investigation of SOM. The PSG records of 24 sleepwalkers, 18-25 years old, and 12 age-matched controls, were analysed. Sleepwalkers had remarkably more epochs containing hypersynchronous delta waves (HSD) (59.6 +/- 60.1 vs. 1.7 +/- 3.2; P less than 0.0001), a higher proportion of HSD/total time spent in stage 3-4 (24.9 +/- 21.1% vs. 1.1 +/- 2.0%, P less than 0.0002), and more stage 3-4 sleep interruptions (8.4 +/- 5.7 vs. 3.7 +/- 1.7, P less than 0.004). They also tended to have a larger proportion of their sleep time in stage 3-4 (30.6 +/- 11.7% vs. 22.6 +/- 6.8%; P less than 0.07). Although their sensitivity and specificity have yet to be more fully investigated, these seem to be quantitative, easy-to-use variables which may characterize adult SOM and may aid in its proper diagnosis.

Adolescent↗
PubMed1990

[Obstructive sleep apnea treated with uvulopalato-pharyngoplasty].

38 patients with sleep apnea syndrome treated with uvulopalato-pharyngoplasty were interviewed 23 +/- 10.8 months after the operation (mean age 48.0 +/- 8.6 years, range 28-65). 22 were also studied in the sleep laboratory 10 +/- 10.7 months after operation. 3 months after operation 94% reported improvement in snoring and 77% improvement in excessive daytime sleepiness. 1 and 2 years after the operation snoring had decreased to 74% and 65%, respectively, and excessive sleepiness to 65%, for both periods. There was a decrease of at least 50% in the number of apneic periods per hour of sleep in 68%. Side-effects consisted of nasal regurgitation and vocal changes. Only age was of predictive value: the younger the patient the better the response.

Adult↗
PubMed1988

Narcolepsy-cataplexy in Israeli Jews is associated exclusively with the HLA DR2 haplotype. A study at the serological and genomic level.

Narcolepsy is a very rare disease among Israeli Jews with a frequency of 7/3 X 10(6). An investigation of the association of narcolepsy with the human leukocyte antigen system was conducted in Israeli Jews at the serologic and genomic levels. The human leukocyte antigen class I and class II antigen typing of 7 clinically diagnosed narcoleptics, 3 individuals suffering from sleep disorders other than narcolepsy, and 11 healthy matched controls revealed that all narcoleptic patients (100%) investigated in the present study carried the HLA-DR2 haplotype, whereas patients with other sleep disorders did not. The HLA-B7 and DR2 occurred jointly in 57% (4/7) of the narcoleptic patients, as compared to 2% in randomly selected Israeli healthy controls. Restriction fragment length polymorphism analysis was performed with several restriction enzymes and three cDNA probes for DQ alpha, DQ beta, and DR beta genes on genomic DNAs obtained from narcoleptics and patients with other sleep disorders, matched controls, and 3 homozygous typing cells representing the DR2 subtypes Dw2, Dw12, and DwAZH. The restriction fragment length polymorphism analysis showed that all narcoleptics (7 of 7) shared virtually identical restriction fragment length polymorphisms with one of the homozygous typing cells (GSO), which defines DR2,Dw2. The frequency of the DR2,Dw2 haplotype in the healthy Israeli population is 3.2%. Other non-narcoleptic patients did not share these restriction fragment length polymorphisms. These findings indicate that narcolepsy is associated worldwide with the HLA-DR2,Dw2 haplotype.

Adult↗
PubMed1988

Sleep paralysis: a study in family practice.

Over a period of two years, five patients with sleep paralysis referred themselves to four family practices in Israel serving a population of 6800. None of the patients suffered from daytime sleep attacks or cataplexy and all were from the oriental (sephardi) community. The two who were tissue typed had HLA haplotypes different from those which are exclusively associated with narcolepsy and one of them who also underwent polysomnography had a normal tracing. There was considerable delay in consulting a physician despite the physical and mental anguish caused by the disorder and some improvement was noted once the diagnosis was explained. The serious nature of the components of the differential diagnosis - myocardial infarction, seizure disorder, cardiac arrest, anaesthetic accident - makes it important that sleep paralysis be more widely recognized.

Adult↗