Population genetics of phenylketonuria

Phenylketonuria (PKU) is an autosomal recessive disorder caused by a large number of mutations at the phenylalanine hydroxylase (PAH) locus, most of which are strongly associated with specific RFLP or VNTR haplotypes. One of the major questions remaining in PKU research is why this apparently maladaptive disorder has been maintained at a frequency of approximately 1 in 10000 among Caucasians. A growing number of studies have provided evidence that both the relatively high frequency of PKU and the strong mutation/haplotype associations might reflect the existence of multiple founding populations for PKU. Examples of putative founding populations for PKU in both Europe and Asia will be presented. Some PAH mutations are associated with multiple haplotypes, suggesting recurrence. Evidence for and against recurrence as the mechanism responsible for the association of the R408W mutation with RFLP haplotypes 1 and 2 will be discussed.     

Molecular analysis of PKU in Ireland

Classical phenylketonuria (PKU: McKusick No. 261600) is caused by mutations occurring at the phenylalanine hydroxylase (PAH) locus on chromosome 12 and has a prevalence in Ireland of 1 in 4500. We examined 304 independent alleles from 350 patients for the presence of six mutations and have characterized VNTR alleles within the minisatellite region 3' to the PAH gene in patients carrying the most prevalent mutation. R408W was the most common mutation found, with a relative frequency of 42%. All other mutations had relative frequencies of <10%. VNTR analysis showed that the R408W mutation is associated with the VNTR-8 allele in the Irish population, indicating that R408W is associated with RFLP haplotype 1. This differs from that reported from eastern Europe where R408W is associated with RFLP haplotype 2/VNTR-3; an observation which has led several groups to propose a Balto-Slavic origin for this mutation. These results support the hypothesis of a second, independent founding event for the R408W mutation on an RFLP haplotype 1 VNTR-8 chromsome background in the Irish/Celtic population.     

Prevalence of behaviour disorders in low birthweight infants

OBJECTIVE--To determine the prevalence of behaviour disorders in low birthweight infants. DESIGN--Children of birth weight < or = 2000 g born to mothers resident in Merseyside in 1980-1 assessed using the Rutter parent and teacher behaviour questionnaires and the Conner modification of the Rutter teacher questionnaire. Children attending normal schools were assessed with controls matched for age, sex, and class in school. Children attending special schools were assessed unmatched. SUBJECTS--233 matched case-control pairs attending normal primary schools and 46 unmatched children attending special schools. SETTING--Primary and special schools. MAIN OUTCOME MEASURES--Emotional, conduct, and undifferentiated behaviour disorders and hyperactivity. RESULTS--On the parental questionnaire screen, 36% of the cases and 22% of the controls had a behaviour disorder and on the teacher questionnaire the proportions were 27% and 12% respectively. Hyperactivity was significantly more common among male cases than their controls (21% v 5.0%) but differed little among female cases and controls (9% v 7%). CONCLUSIONS--Improving neonatal survival of low birthweight infants is accompanied by a higher prevalence of behaviour disorders. The long term implications for psychiatric morbidity and other adult disease must be monitored.     

CLINICO-EPIDEMIOLOGICAL ALGORITHM FOR PREDICTING SYSTEMIC ARTERIAL HYPERTENSION AT HIGH ALTITUDE THROUGH MATHEMATICAL MODELLING

A population based hybrid design combining element of cohort and cross-sectional approach was used to develop a simple clinical algorithm to predict individual probability of developing hypertension (systolic BP > 140 mm Hg and/or diastolic BP > 90 mmHg). 3615 soldiers initially normotensive at the time of induction into high altitude, were studied by systematic random sampling. Multiple logistic regression analysis showed a high significant association between hypertension and age, body mass index (BMI), tobacco smoking and alcohol consumption. Using the constant/coefficient values obtained from the logistic model and the receiver operating characteristics (ROC) curve analysis, the following predictive rule was developed – To the age in years, add (BMIx 3.86); also add 5.53 if he is a smoker; and add 19.81 if he consumes alcohol. If the total exceeds 142, the individual is at high risk of developing hypertension. This algorithm carries a sensitivity of 68.2% and specificity of 78.5%.KEY WORDS: Hypertension, High altitude     

Misoprostol as aid in First Trimester MTP

Background

Medical Termination of Pregnancy (MTP) is a commonly performed during the first trimester. Dilatation and Evacuation (D & E) mandates rapid dilatation of cervix with metal dilators, which requires anaesthesia and may be associated with trauma to the uterus, cervix and later cervical incompetence. The problem of rapid cervical dilatation is obviated with intravaginal misoprostol.

Methods

Intravaginal misoprostol tablet 200 microgram was inserted, a night prior to MTP to ripen the cervix. Cervix was dilated with metal dilators only in cases where cervix did not loosen up sufficiently. Products of conception were removed by suction.

Results

Out of 108 cases cervical dilatation was not required in 96 cases (88.9%).

Conclusion

Intravaginal misoprostol 200 microgram proved effective as a priming agent prior to MTP in the first trimester.Key Words: Misoprostol, MTP     

Amine-guanidine switch: a promising approach to improve DNA binding and antiproliferative activities

A series of polyaromatic guanidino derivatives was synthesized and evaluated for growth inhibitory properties in several human carcinoma cell lines. The properties of these guanidino compounds were compared to those of their corresponding synthetic amino precursors. The size of the polyaromatic ring system as well as the length of the tether attached to the ring had a direct impact on the observed antiproliferative profiles, compound 14 having the broadest spectrum of activity. As both series intercalate DNA, guanidine derivatives showed a remarkable affinity for DNA and the guanidinium group appeared to be essential, yet not sufficient for caspase-3/7 activation. Compound 14 also showed significant in vivo activity against breast cancer cell xenografts in NOG/SCID mice. These results suggest that the electronic nature of chain tethering an intercalator not only influences the DNA-binding process but also controls the antitumoral activity of the whole compound.     

A simulator for maxillofacial surgery integrating 3D cephalometry and orthodontia.

OBJECTIVES: This paper presents a new simulator for maxillofacial surgery that gathers the dental and maxillofacial analyses together into a single computer-assisted procedure. The idea is to first propose a repositioning of the maxilla via the introduction of 3D cephalometry applied to a 3D virtual model of the patient's skull. Orthodontic data are then integrated into this model, using optical measurements of plaster casts of the teeth. MATERIALS AND METHODS: The feasibility of the maxillofacial demonstrator was first evaluated on a dry skull. To simulate malformations (and thus simulate a "real" patient), the skull was modified and manually cut by the surgeon to generate a given maxillofacial malformation (with asymmetries in the sagittal, frontal, and axial planes). RESULTS: The validation of our simulator consisted of evaluating its ability to propose a bone repositioning diagnosis that would restore the skull to its original configuration. An initial qualitative validation is provided in this paper, with a 1.5-mm error in the repositioning diagnosis. CONCLUSIONS: These results mainly validate the concept of a maxillofacial numerical simulator that integrates 3D cephalometry and guarantees a correct dental occlusion.     

Progesterone receptors A and B differentially modulate corticotropin-releasing hormone gene expression through a cAMP regulatory element

Corticotrophin-releasing hormone (CRH) plays a major role in mechanisms controlling human pregnancy and parturition. Gene regulation by progesterone may be a key point in the control of placental CRH production. Studies in primary placental ceils show that antagonism of progesterone activity or production by RU486 or trilostane leads to an increase in CRH promoter activity. This effect can be reversed by the addition of progesterone. Overexpression of progesterone receptor A (PRA) or glucocorticoid receptor resulted in a decrease in CRH promoter activity following progesterone treatment, whereas an increase in promoter activity was observed with overexpressed PR-B.     

Estrogen receptor-mediated down-regulation of corticotropin-releasing hormone gene expression is dependent on a cyclic adenosine 3＇ ,5＇-monophosphate regulatory element in human placental syncytiotrophoblast cells

Placental CRH plays a major role in the mechanisms controlling human pregnancy and parturition. Understanding how placental CRH production is regulated is therefore of importance. Previously we have shown that placental expression of CRH peptide and mRNA are inhibited by estrogens, in contrast to the stimulatory effects of estrogen on hypothalamic CRH production. Our current study found that in placental cells cotransfected with a CRH promoter construct and an estrogen receptor-alpha expression vector results in a differential regulation whereby 17beta estradiol (E2) decreased and the putative pure estrogen antagonist, ICI 182780,