Myosin VIIA gene: heterogeneity of the mutations responsible for Usher syndrome type IB

Usher syndrome is recognized as the most frequent cause of hereditary deaf-blindness. Usher syndrome type I (USH1), the most severe form of the disease, is characterized by profound congenital sensorineural deafness, constant vestibular dysfunction, and retinitis pigmentosa of prepubertal onset. This form is genetically heterogeneous and five loci (USH1A-E) have been mapped thusfar. However, only the gene responsible for USH1 B (which accounts for approximately 75% of USH1 cases) has been characterized. It encodes a long-tailed unconventional myosin, myosin VIIA, with a predicted 2215 amino acid sequence. Primers covering the complete myosin VIIA coding sequence as well as the 3' non coding sequence were designed, allowing direct sequence analysis of each of the 48 coding exons and flanking splice sites in seven patients affected by USH1. Four novel mutations were thereby identified. The possibility should now be considered of a sequence-based prenatal diagnosis in some of the families affected by this very severe form of Usher syndrome.      

Low negative affect prior to treatment is associated with a decreased chance of live birth from a first IVF cycle

BACKGROUND: Psychological variables, such as anxiety and depression, may have a negative impact on IVF outcomes, but the evidence remains inconclusive. Previous studies have usually measured a single psychological parameter with clinical pregnancy as the outcome. The objective of the current study was to determine whether pretreatment or procedural psychological variables in women undergoing a first IVF cycle affect the chance of achieving a live birth from that cycle. METHODS: Between February 2002 and February 2004, 391 women with an indication for IVF were recruited at two University Medical Centres in The Netherlands. Pretreatment anxiety and depression were measured with the Hospital Anxiety and Depression Scale. The Daily Record Keeping Chart was used to measure negative and positive affect before treatment and daily during ovarian stimulation. Multiple stepwise forward logistic regression analysis was performed with term live birth as the dependent variable. RESULTS: Regression analysis showed that women who expressed less negative affect at baseline were less likely to achieve live birth (P = 0.03). After one IVF cycle, women who received a standard IVF strategy were more likely to reach live birth delivery than those who received a mild IVF strategy (P = 0.002). A male/female indication for IVF was associated with a higher chance of achieving term live birth than a female only indication (P = 0.03). Age, duration of infertility or type of infertility were not independent predictors of live birth. CONCLUSIONS: The relationship between psychological parameters and IVF success rates is more complex than commonly believed. The expression of negative emotions before starting IVF might not be always detrimental for outcomes.     

Cardiac abnormalities in end stage renal failure and anaemia

Thirteen anaemic children on dialysis were assessed to determine the incidence of cardiac changes in end stage renal failure. Nine children had an increased cardiothoracic ratio on radiography. The electrocardiogram was abnormal in every case but no child had left ventricular hypertrophy as assessed by voltage criteria. However, left ventricular hypertrophy, often gross, was found on echocardiography in 12 children and affected the interventricular septum disproportionately. Cardiac index was increased in 10 patients as a result of an increased left ventricular stroke volume rather than heart rate. Left ventricular hypertrophy was significantly greater in those on treatment for hypertension and in those with the highest cardiac index. Abnormal diastolic ventricular function was found in 6/11 children. Children with end stage renal failure have significant cardiac abnormalities that are likely to contribute to the high cardiovascular mortality in this group. Anaemia and hypertension, or its treatment, probably contribute to these changes. Voltage criteria on electrocardiogram are of no value in detecting left ventricular hypertrophy. Echocardiography must be performed, with the results corrected for age and surface area, in order to detect and follow these abnormalities.     

Chronic pain and its impact on quality of life in adolescents and their families

OBJECTIVE: To study chronic pain not caused by somatic disease in adolescents and the effect of pain on the quality of life of the adolescents and their families. METHODS: One hundred twenty-eight youngsters (12-18 years) who had reported chronic pain kept a 3-week diary of their pain and completed a questionnaire on quality of life. Their mothers completed a questionnaire on the impact of their youngster's pain on the family. RESULTS: The most prevalent pains were limb pain, headache, abdominal, and back pain. The pain increased during the day, with the highest frequency around dinner time and the highest intensity around bedtime. Girls reported more intense and more frequent pain than boys. The higher the intensity and frequency of the pain, the lower the self-reported quality of life of the female or male adolescent, especially regarding psychological functioning (e.g. feeling less at ease), physical status (a greater incidence of other somatic complaints), and functional status (more impediments to leisure and daily activities). Chronic pain also had a negative impact on family life. The mothers reported restrictions, particularly in social life, and problems dealing with the stress of the adolescent's pain. CONCLUSIONS: Chronic pain, not caused by somatic disease, was present to a higher degree in girls; the pain increased during the day and had a negative impact on quality of life of the adolescents and the family. There is a need for future research aimed at identifying risk factors for chronic pain and pain-associated quality of life in children and adolescents.     

Prolonged duration local anesthesia from tetrodotoxin-enhanced local anesthetic microspheres

There is interest in developing prolonged duration local anesthesics. Here we examine whether tetrodotoxin (TTX) can be used to prolong the block from bupivacaine microspheres with and without dexamethasone. Rats received sciatic nerve blocks with 75 mg of microspheres containing 0.05% (w/w) TTX, 50% (w/w) bupivacaine and/or 0.05% (w/w) dexamethasone. 0.1% (w/w) TTX microspheres were also tested. The carrier fluid contained 1:100,000 epinephrine. Nociceptive and motor blockade of the hindpaw were quantified. Nerves and adjacent muscles were harvested 2 weeks after injection for histological assessment by light microscopy. The median nociceptive block duration in hours from the microsphere groups were: bupivacaine=6.2, 0.05% TTX=0, bupivacaine+TTX=35.3, bupivacaine+dexamethasone=31.3, TTX+dexamethasone=8.1, TTX+bupivacaine+dexamethasone=221.7. Some animals receiving particles containing 0.05% TTX had deficits in the uninjected extremity; all animals receiving 0.1% (w/w) TTX particles died. Pockets of particles were associated with localized inflammation, and all samples showed some evidence of myotoxicity in the vicinity of the injection. The nerves themselves appeared intact. In summary, coencapsulation of TTX in controlled release devices containing bupivacaine and dexamethasone resulted in very prolonged nerve blocks. As formulated here, this preparation had a narrow margin of safety. While the myotoxicity appears consistent with the well-known reversible myotoxicity associated with local anesthetics, its long-term significance remains to be established.     

Chronic pain among children and adolescents: physician consultation and medication use

OBJECTIVE: The goal of this study was to assess physician consultation and use of medication in Dutch children and adolescents (0-18 years old) having chronic pain in relation to sociodemographic factors and pain characteristics. DESIGN: This was a population-based cross-sectional survey. A questionnaire was either mailed to the participants' parents or distributed at school, and it was filled out by the parents (for children aged 0-7 years) or by the participant (for children and adolescents aged 8-18 years). SETTING: The study was conducted in the Rotterdam area. PATIENTS: Participants included a random sample of 1,300 children aged 0 to 3 years taken from the register of population. In addition, 41 schools were selected to obtain a representative sample of 5,336 children and adolescents aged 4 to 18 years. OUTCOME MEASURES: Reported physician consultation and medication use were assessed. RESULTS: Of the 6,636 children and adolescents surveyed, 5,424 (82%) responded. A total of 1,358 respondents (25%) reported chronic pain. Of these, 57% had consulted a physician and 39% had used medication for the pain. Respondents with earache, more intense pain, and more frequent pain and those attending lower vocational training programs were more likely to consult a physician for the pain than the average respondent. Respondents with earache, sore throat, headache, more intense pain, and multiple pain; children aged 0 to 3 years; and girls were more likely to use medication for the pain. Logistic regression analyses showed that for physician consultation, the most significant predictive factors were the intensity of pain, age, and earache as well as the level of education for respondents aged 12 to 16 years. The use of medication was predicted by earache, headache, limb pain, intensity of pain, and age. CONCLUSIONS: Chronic pain is a common complaint in children and adolescents, frequently resulting in consultation of a physician and medication use. Regarding physician consultation, children and adolescents with a lower educational level seem to be a group at risk.     

Influence of clinical status on the association between plasma total and unbound bilirubin and death or adverse neurodevelopmental outcomes in extremely low birth weight infants

Objectives: To assess the influence of clinical status on the association between total plasma bilirubin and unbound bilirubin on death or adverse neurodevelopmental outcomes at 18–22 months corrected age in extremely low birth weight infants. Method: Total plasma bilirubin and unbound bilirubin were measured in 1101 extremely low birth weight infants at 5 ± 1 days of age. Clinical criteria were used to classify infants as clinically stable or unstable. Survivors were examined at 18–22 months corrected age by certified examiners. Outcome variables were death or neurodevelopmental impairment, death or cerebral palsy, death or hearing loss, and death prior to follow‐up. For all outcomes, the interaction between bilirubin variables and clinical status was assessed in logistic regression analyses adjusted for multiple risk factors. Results: Regardless of clinical status, an increasing level of unbound bilirubin was associated with higher rates of death or neurodevelopmental impairment, death or cerebral palsy, death or hearing loss and death before follow‐up. Total plasma bilirubin values were directly associated with death or neurodevelopmental impairment, death or cerebral palsy, death or hearing loss, and death before follow‐up in unstable infants, but not in stable infants. An inverse association between total plasma bilirubin and death or cerebral palsy was found in stable infants. Conclusions: In extremely low birth weight infants, clinical status at 5 days of age affects the association between total plasma bilirubin and death or adverse neurodevelopmental outcomes at 18–22 months of corrected age. An increasing level of UB is associated a higher risk of death or adverse neurodevelopmental outcomes regardless of clinical status. Increasing levels of total plasma bilirubin are directly associated with increasing risk of death or adverse neurodevelopmental outcomes in unstable, but not in stable infants.     

Effect of CYP2C19*2 and *17 mutations on pharmacodynamics and kinetics of proton pump inhibitors in Caucasians

AIMS

To investigate the impact of CYP2C19 mutations *2-*6 and *17 on acid-inhibition and pharmacokinetics of lansoprazole (L15), omeprazole (O10, O20) and pantoprazole (P40) in Caucasians.

METHODS

CYP2C19 genotyping for *2–*6 and *17 mutations was assessed in subjects who were H. pylori negative in two randomized crossover trials. The influence of CYP2C19 mutations on single and repeated administration of L15 and O10 (study A) and O20 and P40 (study B) was investigated. Pharmacokinetics and the cumulative percentage of time with intragastric pH above 4 (% > pH 4) were assessed on day 1 and 6.

RESULTS

For study A CYP2C19 genotyping found five *1/*1, four *1/*2, one *1/*17 and one *2/*17. For study B the results were six *1/*1, two *1/*2, six *1/*17, one *2/*2 and one *2/*17. For all PPIs AUC was highest in *2/*2 and lowest in *1/*17. On day 1, all PPIs significantly increased percentage >pH 4 compared with baseline. *1/*1 genotype showed no significant acid-inhibition after L15, O10 and O20. *1/*17 genotype showed no significant acid-inhibition after O20 and P40. *1/*2 genotype showed significant acid-inhibition after L15 and O10. On day 6, all four PPIs showed significantly increased acid-inhibition. *1/*1 and *1/*17 showed a significantly increased percentage > pH 4 after treatment with O20 and P40. However, in *1/*1 subjects percentage > pH 4 was not significantly increased after L15 and O10. *1/*2 genotype showed a significant acid-inhibitory effect after repeated dosing with L15 and O10.

CONCLUSIONS

Caucasian subjects with *1/*1 and *1/*17 genotype need stronger acid-suppression therapy, especially during the first days of treatment or with on-demand therapy.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

• The influence of CYP2C19 on the kinetics and dynamics of omeprazole, lansoprazole and rabeprazole has been studied in Japanese subjects.
• It has been suggested that subjects with *1/*1 genotype might need stronger acid suppression than *1/*2 and *2/*2 subjects. This suggestion comes from data in Japanese subjects and has not been confirmed in Caucasians.
• Furthermore, a novel CYP2C19 mutation, *17, which mainly occurs in Caucasians has been discovered. This mutation has been associated with clinical failure, but its relevance for therapy with PPIs has not been studied yet.

WHAT THIS STUDY ADDS

• In this study, the influence of CYP2C19 on both the pharmacokinetics and dynamics in Caucasian subjects after single and repeated dosing has been investigated.
• This is the first study showing that Caucasian subjects with *1/*1 and *1/*17 mutations need stronger acid-inhibition. In this study three proton pump inhibitors (omeprazole, lansoprazole and pantoprazole, in different doses) were studied of which pantoprazole had not been studied before in this setting, not even in Japanese.