Biomedical subjects

C Maayan

Publications and source records attributed to C Maayan.

At least 37 records · Page 2Linked to original sources

PubMed1995

Prenatal diagnostic testing for familial dysautonomia using linked genetic markers.

Familial dysautonomia (FD), a recessively inherited disease, has been mapped to chromosome 9q31. Highly polymorphic dinucleotide repeat markers flanking the genetic locus and at the same genetic location have been identified. We describe the prenatal diagnosis of FD using linkage and linkage disequilibrium analyses with these markers. Twelve families were analysed for informativeness and of these, seven went on to have prenatal testing (a total of eight fetuses tested). All of these fetuses were predicted to be heterozygous unaffected (FD carriers). Seven fetuses have come to term and are normal. In the absence of a recombinant proband, a panel of three proximal and three distal markers is sufficient to provide informative flanking markers and an 87-96 per cent likelihood of a highly predictive test. In an additional family at 1:4 risk for FD, no DNA was available from the propositus. This family was analysed using linkage disequilibrium to the #18 allele of the tightly linked marker D9S58 in conjunction with linkage analysis using data from two unaffected children. Prenatal diagnosis in this family indicated an affected fetus.

Base Sequence↗

PubMed1994

[Diagnosis and misdiagnosis in familial dysautonomia].

The method of diagnosis in 122 patients with familial dysautonomia (FD) was reviewed. In all cases the diagnosis was based on the clinical history, physical examination and results of the histamine test (concentrations of 1:1,000 and 1:10,000). In 8 patients the diagnosis was also supported by a meiotic response to pilocarpine (0.0625 mg/dl). 69 (56%) were diagnosed in the first year of life (19 of them relatives of known FD patients), 16 (13%) in the second year, 31 (25%) from 25 months to 10 years, 3 (2%) from 10.1-20 years, and 3 from 20.1-44 years. At diagnosis the mean age was 2.9 years (SD 5.84) and the median age 11 months. In 17 diagnosis was delayed by an average of 18.5 months (SD 16.9) from the time FD was initially suspected, mainly because of false interpretation of the histamine test. Early correct diagnosis is essential to prevent unnecessary morbidity and mortality from FD.

Adolescent↗

PubMed1994

Assessment of the ability of young children to use a powder inhaler device (Turbuhaler).

The purpose of the study was to determine the age at which young asthmatic children could master the use of a new powder inhaler device (Turbuhaler). We studied 59 children with asthma between the ages of 3 and 6 years who consecutively attended the asthma clinic of the pediatric department. Efficiency of inhalation and the pharmacological effect of the terbutaline in the inhaler were measured by scores for inhalation technique and clinical response. None of the 3-year-old children used the device efficiently, but 43% of the 4-year-old, 67% of the 5-year-old, and 80% of the 6-year-old children used the inhaler correctly. Although inhaler technique was not perfect in the younger age group, 50% of the 3-year-old children demonstrated clinical improvement of asthma symptoms after inhalation. In the older age groups, 79%, 92%, and 100% of the 4, 5, and 6-year-old children demonstrated clinical improvement of asthma symptoms after inhalation. It is concluded that the new mode of dry powder delivery system (Bricanyl Turbuhaler) can be used in young asthmatic children who are 4 years of age and above.

Age Factors↗

PubMed1994

Chloroquine treatment of interstitial lung disease in children.

Seven children aged 3 months to 11 years with histologically confirmed interstitial lung disease (ILD) [6 with desquamative interstitial pneumonitis (DIP) and 1 with chronic interstitial pneumonitis] were treated with chloroquine, 10 mg/kg/day. One patient, diagnosed late in the course of the disease, died after three weeks of treatment, despite the addition of systemic corticosteroids. Another patient responded to combined therapy with chloroquine and prednisone and had a normal lung biopsy after 6 months of treatment. He underwent surgical repair of mitral valve stenosis and died after extensive brain infarction. The other 5 patients responded well to chloroquine therapy with major improvement in oxygenation within a few weeks and in lung function over the next few months. They remained well clinically and physiologically, including a normal response to incremental exercise, during a mean follow-up period of 9.8 years (range 3.5 to 15.7 years). None of the patients has developed retinopathy or any other ocular complication. Bronchoalveolar lavage was a useful tool for evaluation of the activity of the disease (predominance of neutrophils) in 3 out of 4 patients. We suggest that chloroquine should be considered as an effective treatment in ILD in children. Incremental exercise test may be helpful for routine follow-up and evaluation of the efficacy of a specific treatment.

Child↗

PubMed1994

Scintigraphic evaluation of esophageal transit and gastric emptying in familial dysautonomia.

Gastroesophageal dysfunction is a major cause of morbidity and mortality in patients with familial dysautonomia (FD). Most studies evaluating esophageal and gastric function in FD patients are either insensitive or invasive. Thus we have used a "milk" scan to quantitate abnormalities in esophageal transit and gastric emptying, while searching for gastroesophageal reflux and aspiration in these patients. The quantitative scintigraphic evaluation was performed in 35 patients with FD, 10 of whom were studied after fundoplication, pyloroplasty and gastrostomy. A prolonged esophageal transit time, ranging from 8 s to more than 60 s duration, was demonstrated in 11 patients. Gastroesophageal reflux was detected in 26 patients. In 16 patients delayed gastric emptying ranging from 63-94% was detected at 30 min, and in 13 patients delayed emptying ranging from 37-86% was observed at 120 min. Pulmonary aspiration was detected in 8 non-operated patients, four of whom had abnormal gastric emptying. The scintigraphic analysis of both esophageal transit and gastric emptying in familial dysautonomia is presented, and its role in evaluation and management of these patients discussed.

Adolescent↗

PubMed1993

Complications following oat head aspiration.

We report 5 cases of oat head aspiration in children that resulted in serious complications due to the unidirectional migration of the oat head to the periphery of the lung. The complications included pneumothorax, pneumomediastinum, recurrent hemoptysis, chronic lung disease, bronchiectasis, lobectomy, bronchopleural and bronchocutaneous fistulae, pleural effusion, empyema cavity, and, one not described before, osteomylitis of the rib. Physicians should be aware of the dangers with this particular foreign body aspiration.

Bronchoscopy↗

PubMed1993

Localization of the gene for familial dysautonomia on chromosome 9 and definition of DNA markers for genetic diagnosis.

Familial dysautonomia (DYS), the Riley-Day syndrome, is an autosomal recessive disorder characterized by developmental loss of neurons from the sensory and autonomic nervous system. It is limited to the Ashkenazi Jewish population, where the carrier frequency is 1 in 30. We have mapped the DYS gene to chromosome 9q31-q33 by linkage with ten DNA markers in 26 families. The maximum lod score of 21.1 with no recombinants was achieved with D9S58. This marker also showed strong linkage disequilibrium with DYS, with one allele present on 73% of affected chromosomes compared to 5.4% of controls (chi 2 = 3142, 15 d.f. p < 0.0001). D9S53 and D9S105 represent the closest flanking markers for the disease gene. This localization will permit prenatal diagnosis of DYS in affected families and aid the isolation of the disease gene.

Alleles↗

PubMed1993

Exclusion of familial dysautonomia from more than 60% of the genome.

Familial dysautonomia (FD) is a recessive neurological disorder that affects the development of the sensory and autonomic nervous system. The gene defect appears to be limited to the Ashkenazi Jewish population, where the carrier frequency is 1 in 30. One hundred and ninety-one marker loci representing all autosomes were tested for linkage with the FD genetic defect in 23 families. A combination of pairwise and multipoint analyses excluded the FD gene from at least 60% of the autosomal genome. The program EXCLUDE predicted regions of chromosomes 2, 4, 5q, 9, or 10 as the most promising locations for future analyses.

Chromosome Mapping↗

PubMed1993

Antibodies to human serum albumin in familial dysautonomia.

Sera from familial dysautonomia patients are shown to contain high levels of antibodies to human serum albumin (HSA). The individual levels of anti-HSA antibodies correlate significantly with the levels of antibodies to bovine serum albumin and lactalbumin. These results and the findings that the anti-HSA level declines exponentially with age indicate that anti-HSA antibodies may be induced by aspiration of bovine milk antigens in infancy. The titer of the anti-HSA autoantibodies presently described (> 1:10,000) is much higher than those found in other diseases and may contribute to the pathological changes in familial dysautonomia.

Adult↗

PubMed1993

Home care therapy for respirator-dependent patients.

Our experience with 13 patients suffering from various ventilatory disorders who received mechanical ventilation at home for periods between 1 and 12 years is presented. Seven of the 13 patients were ventilated by positive pressure via tracheostomy, 3 by negative body ventilators and 3 by exufflation belt and positive pressure. Only a few hospitalizations were required due to pulmonary complications, and there was no case of sudden death occurring at home. Costs of home care for respirator-dependent patients, including the initial investment of home equipment, are much lower than the costs of long-term hospital care. A comprehensive home care program should be the preferred choice for medically stable ventilator-dependent patients.

Adolescent↗

PubMed1992

Role of infection in the middle lobe syndrome in asthma.

Twenty one children with asthma aged 1.0-10.5 years (mean (SD) 3.3 (2.5) years) were admitted to the hospital to evaluate pulmonary right middle lobe or lingular collapse lasting one to 12 months (mean (SD) 4.4 (3.8) months). Seven children had mild asthma and were treated with inhaled beta 2 agonists as needed. Nine had moderate asthma treated with either sodium cromoglycate or slow release theophylline. Five had severe asthma treated with inhaled steroids. Each child underwent fibreoptic bronchoscopy under local anaesthesia and a bronchoalveolar lavage. Differential cell counts of the lavage fluid revealed predominance of neutrophils in 12 patients (57%). In nine of these patients cultures grew pathogenic bacteria, mainly Haemophilus influenzae and Streptococcus pneumoniae. There was no correlation between the severity of asthma and a positive bacterial culture. There was also no correlation between the duration of the right middle lobe collapse and a positive culture. We conclude that longstanding right middle lobe collapse in asthmatic children is often associated with bacterial infection.

Asthma↗

PubMed1992

Respiratory system stability and abnormal carbon dioxide homeostasis.

We have tested the hypothesis that interactions among eight parameters of the respiratory and cardiovascular systems that determine the loop gain (LG) of the respiratory CO2 feedback control system might account for the degree of stability or instability of breathing patterns in healthy sleeping volunteers as well as in familial dysautonomia (FD) and congenital central hypoventilation syndrome (CCHS) patients. The predictability of cycle duration was tested as well. We measured the values of CO2 sensitivity, CO2 delivery capacity in the circulation, circulation delay, mean lung volume for CO2, and mixed venous PCO2 in 8 FD patients, 2 CCHS patients, and 19 healthy controls. The values of these parameters were used in a mathematical model to compute the LG of the respiratory control system during sleep for each epoch of respiration analyzed. The strength of the ventilatory oscillations (R) was quantified using power density spectra of the ventilation time series. All subjects were studied at inspiratory O2 concentrations (FIO2) of 0.21 and 0.15; CCHS patients and controls were also studied at 0.12 FIO2 to examine the effect of steady-state hypoxia on respiratory system stability. In 2 FD patients, LG was elevated at both levels of FIO2 and periodic breathing was observed; the values of R were elevated. Elevated mixed venous PCO2 and reduced CO2 delivery capacity were chiefly responsible for the abnormally high LG observed. In three healthy volunteers, high LG and unstable patterns were associated with high chemosensitivity. The CCHS patients, however, remained stable even at 0.12 FIO2 because LG remained equivalent to zero due to a lack of chemosensitivity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1991

Malignant peritoneal mesothelioma: long-term spontaneous clinical remission.

Prolonged spontaneous clinical remission in a patient with malignant peritoneal mesothelioma is described. The case is also unique because of the presence of high-spiking fevers as a symptom of tumor recurrence and the finding of an elevated titer of rheumatoid factor in the ascitic fluid. The caution needed in interpreting results of therapeutic interventions in this tumor is emphasized.

Adult↗

PubMed1991

Cesarean section by local anesthesia in patients with familial dysautonomia.

We describe a 29-year-old patient with familial dysautonomia who underwent cesarean section because of severe intrauterine fetal growth retardation. The surgery was done after induction of local anesthesia to avoid the critical and sometimes fatal complications of general anesthesia known in patients with familial dysautonomia. Surgery was uneventful and almost painless. The postoperative period was without complications. Induction of local anesthesia for cesarean section may constitute a suitable alternative in patients with familial dysautonomia.

Adult↗

PubMed1991

Exercise but not methacholine differentiates asthma from chronic lung disease in children.

Bronchial provocation challenges with exercise and methacholine were performed on the same day or within a short interval in 52 children with asthma, 22 with other types of chronic lung disease (including cystic fibrosis), and 19 control subjects with no evidence of chronic lung disease. There were no significant differences in the baseline lung function before the two types of challenge in the individual groups and differences between the patients with asthma and with chronic lung disease were minor. When the mean -2 SD of the methacholine response of the control group was taken as the lower limit of normal, 49/52 (94%) patients with asthma and 18/22 (82%) with chronic lung disease responded abnormally. In contrast, with the mean +2 SD of the exercise response of the control group as the upper limit of normal, 41/52 (79%) asthmatic patients responded but none of those with chronic lung disease. Thus the response to the two types of challenge helps to distinguish asthma from other types of chronic lung disease in children.

Adolescent↗

PubMed1990

Interaction between respiratory and RR interval oscillations at low frequencies.

Oscillations in RR interval between 0.02 and 1.00 cycles per second (Hz) have been related to the action of the autonomic nervous system. Respiration has been shown to influence RR interval at normal breathing frequencies between approximately 0.16 and 0.5 Hz in children and adults--a phenomenon known as respiratory sinus arrhythmia. In this study we investigated the effect of respiration on RR interval in a lower frequency range between 0.02 and 0.12 Hz. Low frequency oscillations in respiration were induced in healthy sleeping adult subjects via the administration of a bolus of CO2 during inhalation. Power spectra of RR interval and respiration were obtained before and after the CO2 pulse, and the frequency content in the low frequency range was quantitatively compared. An increase in the spectral energy in both respiration and RR interval was observed for the group. However, this increase was accounted for by six of 29 epochs. We conclude that respiration (tidal volume) can influence RR interval at frequencies below those usually associated with respiratory sinus arrhythmia. This influence may be mediated through a sympathetic reflex. This result is applicable to the measurement and interpretation of heart rate variability and to autonomic influences of low frequency fluctuations in RR interval.

Adolescent↗

PubMed1990

Megaesophagus and recurrent apnea in an adult patient with familial dysautonomia.

A 42-yr-old woman with familial dysautonomia (FD) presented with severe episodes of apnea during the daytime, as well as during sleep. Investigations revealed a megaesophagus and a lower esophageal constriction. These caused accumulation of food in the esophagus, resulting in recurrent aspiration and apnea which disappeared after gastrostomy. Megaesophagus, a rare complication in FD patients, can occur in other diseases with autonomic dysfunctions, and one must be aware of its potential respiratory complications.

Adult↗

PubMed1989

Breath-by-breath respiratory timing and volume control during periodic breathing.

We examined the control of respiratory pattern during non-rapid-eye-movement sleep-related periodic breathing (PB) in adults, with and without hypoxia. We analyzed 186 cycles of PB from 18 epochs occurring in eight subjects; the mean (+/- SD) cycle duration was 30.8 +/- 8.4 s. Significant oscillations occurred in inspired tidal volume (VT), inspiratory duration (TI), mean inspired flow, inspired minute ventilation, and expiratory duration (TE) (P less than 0.005). For each epoch of PB, moving cross-correlation (MCC) functions were employed to describe the time-dependent intervariable relationships between 1) TI vs. TE, 2) VT vs. TE, and 3) VT vs. breath duration (TT) as synchronization, a strong and consistent intervariable correlation; relative coordination (RC), a weaker interaction characterized by an unstable MCC function oscillating at a subharmonic of the PB frequency; or as independence, with no statistical evidence of interaction. Fourteen epochs showed RC between TI and TE, 11 and 12 of which also showed RC between VT and TE, and VT and TT, respectively. In 4 epochs negative synchronization was exhibited by all three variable pairs. In no case were the oscillations between any pair of variables independent. The modes of coupling between variables were not correlated to O2 saturation, end-tidal CO2 levels, or inspired O2 level. We conclude that during sleep-related PB a nonrandom but weak coupling usually exists between TI and TE, VT and TE, and VT and TT.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗