Allele sharing at six VNTR loci and genetic distances among three ethnically defined human populations

Because of their high degree of polymorphisms, the variable number of tandem repeat (VNTR) loci have become extremely useful in studies involving gene mapping, determination of identity and relatedness of individuals, and evolutionary relationships among populations. However, there are some concerns regarding whether or not the patterns of such genetic variation can be studied by the classical population models that are developed for studying genetic variation at blood groups and protein loci, since VNTR alleles detected by molecular size may not always be identical by descent. Although theoretical and empirical studies demonstrate that this concern is overstated, this study provides further support of the application of the traditional mutation-drift models to predict the pattern of intra- and inter-populational variation at VNTR loci. By comparing genetic variation at six VNTR loci with that at 16 blood groups and protein loci in three ethnically defined populations, we show that the patterns of variability at these two sets of loci are in general parallel to each other. Shared VNTR alleles among populations are generally more frequent than the ones which are not present in every population; the proportion of shared alleles among populations increases with increasing genetic similarity of populations; and the number of VNTR alleles is positively correlated with gene diversity at these loci. All of these observations are in agreement with the prediction of the mutation-drift models, particularly when the possibility of forward-backward mutations are taken into account. This parallelism of genetic variation at VNTR loci and blood groups/protein loci further asserts the potential of using such hypervariable loci for microevoltionary studies, where closely related populations may exhibit considerably less allele frequency differences at the classical blood group and protein loci. © 1992 Wiley-Liss, Inc.     

Thioredoxin regulation of ischemic preconditioning

Thioredoxins are a class of small redox-regulating proteins that appear to play a crucial role in many oxidative stress-inducible degenerative diseases. A recent study demonstrated a reduction of thioredoxin-1 (Trx1) protein in the ischemic reperfused myocardium. When the same heart was adapted to ischemic stress by preconditioning with repeated cyclic episodes of small duration of ischemia and reperfusion, there was an increased induction of Trx1 expression. Inhibition of Trx1 expression resulted in reduced postischemic ventricular recovery and increased myocardial infarct size in the preconditioned heart. Corroborating these findings, transgenic mouse hearts overexpressing Trx1 were resistant to ischemic reperfusion injury as compared with the hearts from wild-type mice. Thus, it appears that thioredoxin plays a crucial role in cardioprotection induced by preconditioning.     

Respiratory syncytial virus infection: Clinical presentation and management

Summary RSV infection continues to be a major cause of morbidity and mortality throughout the world. Despite advances in the understanding of its pathogenesis, limited progress has been made in prevention and treatment of RSV infection. Based on the experiences thus far it seems that control of RSV infection will be a difficult and complex task.     

Progression or reactivation of Otosclerotic lesion despite Fluoride therapy

Progression or reactivation of Otosclerotic disease as shown by tomography, despitemoderate dosage Sodium Fluoride therapy, is due to poor intestinal absorption of the drug in its enteric coated form. It is also seen when the drug is often temporarily withdrawn. During Sodium Fluoride therapy for Otosclerosis an intestinal absorption test of the preparation is necessary.     

Levonorgestrel-releasing intrauterine system vs. transcervical endometrial resection for dysfunctional uterine bleeding.

OBJECTIVE: To compare the acceptability, efficacy, adverse effects, and user satisfaction of a levonorgestrel intrauterine system (LNG-IUS) and transcervical resection of the endometrium (TCRE) for the treatment of dysfunctional uterine bleeding. METHOD: Of 50 women with a pictoral blood loss assessment chart (PBAC) score of 100 or greater, 25 had a LNG-IUS inserted (Mirena; Schering, Berlin, Germany) and 25 underwent TCRE. Procedure-related complications, PBAC score, hemoglobin levels, adverse effects, and rates of acceptability and satisfaction were recorded at 3-month intervals for a period of 12 months. RESULTS: At the end of 1 year there were a 97% and a 94% reduction in menstrual blood loss in the LNG-IUS and TCRE groups, respectively, and hemoglobin concentration had increased by 5.5% in the LNG-IUS group and 5.2% in the TCRE group. Adverse effects were similar in both groups except for systemic effects, which were seen only in the LNG-IUS group. Satisfaction rates were about 80% in the 2 groups. CONCLUSION: Both treatments were found to be equally effective but LNG-IUS placement requires less operator skill and entails no operative hazards, and the device provides effective contraception.     

A new rosette in retinoblastoma

Retinoblastoma, the most common primary malignant intraocular tumor of childhood is a great success story in pediatric and ocular oncology. Pathology of retinoblastoma is important to guide the treatment modalities. Differentiated retinoblastoma is commonly seen in younger age group. Since a hundred years, we have been observing two typical true rosettes in retinoblastoma in the form of Flexner-Wintersteiner (FW) and Homer Wright (HW) rosettes and in many occasions pseudorosettes have been documented. In the present case report, a third new type of rosette was identified in a differentiated retinoblastoma which had an unusual anterior segment involvement.     

A Comparison of Microdebrider Assisted Endoscopic Sinus Surgery and Conventional Endoscopic Sinus Surgery for Nasal Polypi

Nasal polyposis is often encountered in rhinology practice. Those who fail conservative management, a definitive surgery is essential to achieve sufficient ventilation and drainage of the affected sinuses by using either microdebrider or conventional instruments for functional endoscopic sinus surgery (FESS). A prospective study was conducted on 40 cases of nasal polypi in a tertiary care hospital. 20 cases were operated by conventional endoscopic instruments and 20 using the microdebrider. The study aimed at comparing the intra operative (blood loss, duration of surgery) and post operative results (crusting, scarring, discharge, symptoms, recurrence) between the two groups using Lund–Mackay scoring system and the data was statistically analysed. There was no statistically significant difference in surgical outcome for patients when either conventional endoscopic instruments or microdebrider was used. However, there was a significant symptomatic improvement in cases undergoing microdebrider FESS. Microdebrider assisted polypectomy is precise, relatively bloodless surgery though the precision depends on the surgeon’s anatomical knowledge and operative skills. Study substantiates that these instruments are helpful but not a prerequisite for successful outcomes in FESS. The study re-emphasises the utility of the microdebrider to young learning FESS surgeons.