X-linked liver glycogenosis type II (XLG II) is caused by mutations in PHKA2, the gene encoding the liver alpha subunit of phosphorylase kinase

X-linked liver glycogenosis type II (XLG II) is a recently described X- linked liver glycogen storage disease, mainly characterized by enlarged liver and growth retardation. These clinical symptoms are very similar to those of XLG I. In contrast to XLG I patients, however, XLG II patients do not show an in vitro enzymatic deficiency of phosphorylase kinase (PHK). Recently, mutations were identified in the gene encoding the liver alpha subunit of PHK (PHKA2) in XLG I patients. We have now studied the PHKA2 gene of four unrelated XLG II patients and identified four different mutations in the open reading frame, including a deletion of three nucleotides, an insertion of six nucleotides and two missense mutations. These results indicate that XLG II is due to mutations in PHKA2. In contrast to XLG I, XLG II is caused by mutations that lead to minor structural abnormalities in the primary structure of the liver alpha subunit of PHK. These mutations are found in a conserved RXX(X)T motif, resembling known phosphorylation sites that might be involved in the regulation of PHK. These findings might explain why the in vitro PHK enzymatic activity is not deficient in XLG II, whereas it is in XLG I.      

Long term health and neurodevelopment in children exposed to antiepileptic drugs before birth

Objective: To investigate the frequency of neonatal and later childhood morbidity in children exposed to antiepileptic drugs in utero.

Design: Retrospective population based study.

Setting: Population of the Grampian region of Scotland.

Participants: Mothers taking antiepileptic drugs in pregnancy between 1976 and 2000 were ascertained from hospital obstetric records and 149 (58% of those eligible) took part. They had 293 children whose health and neurodevelopment were assessed.

Main outcome measures: Frequencies of neonatal withdrawal, congenital malformations, childhood onset medical problems, developmental delay, and behaviour disorders.

Results: Neonatal withdrawal was seen in 20% of those exposed to antiepileptic drugs. Congenital malformations occurred in 14% of exposed pregnancies, compared with 5% of non-exposed sibs, and developmental delay in 24% of exposed children, compared with 11% of non-exposed sibs. After excluding cases with a family history of developmental delay, 19% of exposed children and 3% of non-exposed sibs had developmental delay, 31% of exposed children had either major malformations or developmental delay, 52% of exposed children had facial dysmorphism compared with 25% of those not exposed, 31% of exposed children had childhood medical problems (13% of non-exposed sibs), and 20% had behaviour disorders (5% of non-exposed).

Conclusion: Prenatal antiepileptic drug exposure in the setting of maternal epilepsy is associated with developmental delay and later childhood morbidity in addition to congenital malformation.

     

P67L: a cystic fibrosis allele with mild effects found at high frequency in the Scottish population.

Only three mutant cystic fibrosis (CF) alleles have to date been established as conferring a dominant mild effect on affected subjects who are compound heterozygotes. We now add a fourth, P67L, which occurs on about 1.4% of Scottish CF chromosomes. Among 13 patients (12 unrelated) with this allele, the average age at diagnosis was 22.5 +/- 11.3 years. None of the cases had consistently raised sweat chloride concentrations, the average value being 57 +/- 9 mmol/l; 77% of the patients were pancreatic sufficient. When compared to three other established mild CF alleles, R117H, A455E, and 3849 + 10kb C-T, a compound heterozygote for P67L has minimal disease and clinical suspicions are unlikely to be confirmed other than by DNA typing.     

Differential diagnosis of dementia and depression in the elderly using neuropsychological methods

This study examined the utility of the Halstead-Reitan Neuropsychological Battery in the differential diagnosis of dementia, major depression, and general neurological impairment. Orthogonal contrasts between groups showed superior performance for depressives on most Halstead-Reitan subtests. Contrasts between organically impaired groups showed that these groups did not differ significantly (p >.05) on any of the Halstead-Reitan subtests. A step-wise discriminant analysis indicated that on the basis of neuropsychological variables alone, demented patients were differentiated from elderly depressed with clinical levels of accuracy. However, when neurologically impaired and demented patients were considered together in a single group reflecting organic impairment, hits increased dramatically. The results were discussed in terms of their implications for differentially diagnosing dementia and depression in the elderly.     

Removal of dihydroxy-terminated components from monomethoxy-terminated poly(ethylene glycol)

A preparative method to remove dihydroxy-terminated components in a sample of presumably monomethoxy, monohydroxy-terminated poly(ethylene glycol) (PEG) is presented. Purification of the monomethoxy-terminated component allows one to prepare a diblock copolymer of PEG and poly(lactic acid) (PLLA) free of a PLLA-PEG-PLLA triblock copolymer in various biomedical applications of the copolymer. Efficiency of the purification is compared for high osmotic pressure chromatography (HOPC) and preparative size exclusion chromatography (SEC). In HOPC, various types of porous silica particles, surfaces, solvents, polymer concentrations have been screened for the optimal performance. It was found that HOPC is more efficient than SEC, especially HOPC of 30-40 wt% solutions in water by a column packed with acid-washed controlled pore glass is optimal in producing high-purity fractions.     

Andrology: Factors influencing the outcome of in-vitro fertilization with epididymal spermatozoa in irreversible obstructive azoospermia

Microsurgical epididymal sperm aspiration (MESA) and in-vitrofertilization (IVF) were found to offer limited opportunityfor fatherhood to 45 men with obstructive azoospermia, due principallyto poor embryo implantation. Adequate sperm preparations wereobtained in 46/50 treatment cycles (92%), with the best motilityfound in the caput epididymis in 89% of cases. The mean fertilizationrate was 11.2% and fertilization occurred in 23 cycles (50%),with embryo transfer arising from 12/26 men with was aplasia(CAV), 4/9 with genital tract obstruction (EV) and 7/11 withirreversible vasectomy (VV). The overall implantation rate waslow, 8.7% per embryo transfer (11.7% per 2-3 embryo transfers)and was not improved by Fallopian transfer. There were two pregnancies(4% per cycle), both in the EV group where embryo formationand implatation (2/4, 50% per cycle) were optimum even thoughsperm preparations were paradoxically inferior to the CAV andVV groups. The spermatozoa retrieved in the two successful EVcycles were appreciably blood contaminated. Analysis of the21 failed embryo transfers showed delayed fertilization in 10cycles, cystic fibrosis (CF) mutation or familial disease in7/12 CAV men and the VV men were older (P<0.001). A pregnancywhich miscarried arose from a case of Young's syndrome, a carrierof CF mutation DF508. Male factors could thus be implicatedin the high embryo wastage of MESA cycles and might also beinfluencing implantation in other IVF procedures. Where feasible,male reconstructive surgery is preferable unless fertilizationcan be improved, possibly by speedier retrieval techniques orby permitting sperm capacitation in vitro, but probably moreeffectively by micro-assisted insemination.     

Construct validity of the PPVT with neuropsychological, intellectual, and achievement measures

The present investigation examined the construct validity of the Peabody Picture Vocabulary Test (PPVT) with learning-disabled children. The Wechsler Intelligence Scale for Children-Revised (WISC-R), the Wide Range Achievement Test, and the Halstead-Reitan Neuropsychological Battery were administered to 934 learning-disabled children. Seven factors were isolated on the basis of a principal-components factor analysis and Varimax rotation. PPVT scores were found to load on a factor similar to what has been labeled verbal comprehension on the WISC-R with little secondary loadings on any of the remaining six factors. Implications for practitioners and further research were discussed.     

Educational benefits of diversity in medical school: a survey of students.

PURPOSE: Many U.S. medical schools have abandoned affirmative action, limiting the recruitment and reducing the admission of underrepresented minority (URM) students even though research supports the premise that the public benefits from an increase in URM physicians and that URM physicians are likely to serve minority, poor, and Medicaid populations. Faculty and students commonly assume they benefit from peer cultural exchange, and the published evidence for the past two decades supports this notion. This research examined the students' perceptions of the educational merits of a diverse student body by surveying medical students at two schools. METHOD: In 2000, medical students from all four years at Harvard Medical School and the University of California, San Francisco, School of Medicine were enrolled in a telephone survey about the relevance of racial diversity (among students) in their medical education. Students responded to the interviewer's questions on a five-point Likert-type scale. RESULTS: Of the 55% of students who could be located, 97% responded to the survey. Students reported having little intercultural contact during their formative years but significantly more interactions during higher education years, especially in medical school. Students reported contacts with diverse peers greatly enhanced their educational experience. They strongly supported strengthening or maintaining current affirmative action policies in admissions. The responses and demography of the Harvard and UCSF students did not differ significantly, nor did they differ for majority students and URM students-all groups overwhelmingly thought that racial and ethnic diversity among their peers enhanced their education. CONCLUSIONS: Diversity in the student body enhanced the educational experiences of students in two U.S. medical schools.