The Evolution of Computer-Assisted Total Hip Arthroplasty and Relevant Applications / 대한고관절학회지

In total hip arthroplasty (THA), the accurate positioning of implants is the key to achieve a good clinical outcome. Computer-assisted orthopaedic surgery (CAOS) has been developed for more accurate positioning of implants during the THA. There are passive, semi-active, and active systems in CAOS for THA. Navigation is a passive system that only provides information and guidance to the surgeon. There are 3 types of navigation: imageless navigation, computed tomography (CT)-based navigation, and fluoroscopy-based navigation. In imageless navigation system, a new method of registration without the need to register the anterior pelvic plane was introduced. CT-based navigation can be efficiently used for pelvic plane reference, the functional pelvic plane in supine which adjusts anterior pelvic plane sagittal tilt for targeting the cup orientation. Robot-assisted system can be either active or semi-active. The active robotic system performs the preparation for implant positioning as programmed preoperatively. It has been used for only femoral implant cavity preparation. Recently, program for cup positioning was additionally developed. Alternatively, for ease of surgeon acceptance, semi-active robot systems are developed. It was initially applied only for cup positioning. However, with the development of enhanced femoral workflows, this system can now be used to position both cup and stem. Though there have been substantial advancements in computer-assisted THA, its use can still be controversial at present due to the steep learning curve, intraoperative technical issues, high cost and etc. However, in the future, CAOS will certainly enable the surgeon to operate more accurately and lead to improved outcomes in THA as the technology continues to evolve rapidly.

Association of methylenetetrahydrofolate reductase gene polymorphisms & colorectal cancer in India.

Background & objectives: Methylenetetrahydrofolate reductase (MTHFR) is a critical enzyme in folate metabolism and involved in DNA synthesis, DNA repair and DNA methylation. The two common functional polymorphisms of MTHFR, 677 C→T and 1298 A→C have shown to impact several diseases including cancer. This case-control study was undertaken to analyse the association of the MTHFR gene polymorphisms 677 C→T and 1298 A→C and risk of colorectal cancer (CRC). Methods: One hundred patients with a confirmed histopathologic diagnosis of CRC and 86 age and gender matched controls with no history of cancer were taken for this study. DNA was isolated from peripheral blood samples and the genotypes were determined by PCR-RFLP. The risk association was estimated by compounding odds ratio (OR) with 95 per cent confidence interval (CI). Results: Genotype frequency of MTHFR 677 CC, CT and TT were 76.7, 22.1 and 1.16 per cent in controls, and 74, 25 and 1.0 per cent among patients. The ‘T’ allele frequency was 12.21 and 13.5 per cent in controls and patients respectively. The genotype frequency of MTHFR 1298 AA, AC, and CC were 25.6, 58.1 and 16.3 per cent for controls and 22, 70 and 8 per cent for patents respectively. The ‘C’ allele frequency for 1298 A→C was 43.0 and 45.3 per cent respectively for controls and patients. The OR for 677 CT was 1.18 (95% CI 0.59-2.32, P = 0.642), OR for 1298 AC was 1.68 (95% CI 0.92-3.08, P = 0.092) and OR for1298 CC was 0.45 (95% CI 0.18-1.12, P = 0.081). The OR for the combined heterozygous state (677 CT and 1298 AC) was 1.18 (95% CI 0.52-2.64, P =0.697). Interpretation & conclusion: The frequency of the MTHFR 677 TT genotype is rare as compared to 1298 CC genotype in the population studied. There was no association between 677 C→T and 1298 A→C polymorphisms and risk of CRC either individually or in combination. The homozygous state for 1298 A→C polymorphism appears to slightly lower risk of CRC. This needs to be confirmed with a larger sample size.

Methylenetetrahydrofolate reductase gene polymorphisms and risk of acute lymphoblastic leukemia in children.

Introduction: Methylenetetrahydrofolate reductase (MTHFR) is a critical enzyme in folate metabolism and is involved in DNA synthesis, DNA repair and DNA methylation. Genetic polymorphisms of this enzyme have been shown to impact several diseases, including cancer. Leukemias are malignancies arising from rapidly proliferating hematopoietic cells having great requirement of DNA synthesis. This case-control study was undertaken to analyze the association of the MTHFR gene polymorphisms 677 C"T and 1298 A"C and the risk of acute lymphoblastic leukemia in children. Materials and Methods: Eighty-six patients aged below 15 years with a confirmed diagnosis of acute lymphoblastic leukemia (ALL) and 99 matched controls were taken for this study. Analysis of the polymorphisms was done using the polymerase chain reaction -restriction fragment length polymorphism (PCR-RFLP) method. Results: Frequency of MTHFR 677 CC and CT were 85.9% and 14.1% in the controls, and 84.9% and 15.1% in the cases. The 'T' allele frequency was 7% and 7.5% in cases and controls respectively. The frequency of MTHFR 1298 AA, AC, and CC were 28.3%, 55.6% and 16.1% for controls and 23.3%, 59.3% and 17.4% for cases respectively. The 'C' allele frequency for 1298 A→C was 43.9% and 47% respectively for controls and cases. The odds ratio (OR) for C677T was 1.08 (95% CI 0.48- 2.45, p = 0.851) and OR for A1298C was 1.29(95% CI 0.65-2.29, p = 0.46) and OR for 1298 CC was 1.31 (95% CI 0.53-3.26, p =0.56). The OR for the combined heterozygous status (677 CT and 1298 AC) was 1.94 (95% CI 0.58 -6.52, p = 0.286). Conclusion: The prevalence of 'T' allele for 677 MTHFR polymorphism was low in the population studied. There was no association between MTHFR 677 C→T and 1298 A→C gene polymorphisms and risk of ALL, which may be due to the small sample size.

Prevalence of congenital heart diseases in Mysore.

Background: Prevalence studies on Congenital heart Diseases (CHDs) have been done several times world wide and such studies are very limited in Indian populations. A few earlier studies in India have reported an increased prevalence of CHDs ranging from 2.25 to 50.89 per 1000 live births. Aims and Objective: To study the prevalence of congenital heart diseases in Indian population. Materials and Methods: Data on the prevalence of CHDs were collected and analyzed from the three major hospitals of Mysore, Cheluvamba Hospital, CSI Holdsworth Memorial Hospital and J.S.S Hospital from the year 2000 to 2004. Results: The prevalence of CHDs for five years in Mysore hospitals ranges from 6.6 to 13.06 per 1000 live births. The most frequent type of CHD was found to be VSD (40.47%) followed by ASD (19.06%), TOF (13.38%) and PDA (9.53%). It is clear that the maximum CHDs were detected in the first year of life when compared to the later years of life. The prevalence of CHDs in Mysore is increasing from 2000 to 2004 which might be due to the improvement of diagnosis, attention or awareness among the medical authorities on the disease. Conclusion: The prevalence of CHDs in Mysore is not very high as reported in other parts of the country, however; it is an important disease which needs an immediate medical attention.

Modes of genetic transmission of dyslexia in south Indian families.

Background: Dyslexia is a major educational problem, but the studies on genetics of dyslexia are very limited in India. There is a great dearth of proper statistical data to show the incidence of dyslexia in Indian population. More over inheritance pattern of dyslexia is not well established in our population. Aims & Objective: To establish the inheritance pattern of dyslexia in 23 selected families. Materials and Methods: We have ascertained 23 dyslexic probands and their families from the state of Karnataka. Individuals with above 8 years of age, normal performance intelligence quotient (>85) and remarkable deviation in reading and writing skills compared to chronological age were considered for the study. Based on the genetic registry pedigrees of the families were constructed. Results: Based on the affectedness, the dyslexia phenotypes were classified into four types: severe reading spelling deficit, mild reading spelling deficit, severe spelling deficit and mild spelling deficit. Severe dyslexia phenotypes were more frequent than mild phenotypes. Mild spelling deficits were better compensated than the other types. It was found that autosomal dominant inheritance pattern of dyslexia was more prevalent than autosomal recessive and sporadic pattern in the present study. Conclusion: Family history of dyslexia is a consistent risk factor; therefore this knowledge can be applied to the prevention and remediation of dyslexia.

Incipient sexual isolation in the nasuta-albomicans complex of Drosophila: mating preference in male-, female- and multiple-choice mating experiments.

Interracial divergence is an important facet of speciation. The nasuta-albomicans complex of Drosophila with sixteen morphologically identical, karyotypically different but cross-fertile races is an excellent system to study a few dimensions of raciation. Drosophila nasuta nasuta, Drosophila nasuta albomicans, Cytorace 1, Cytorace 2, Cytorace 3 and Cytorace 4 of this subgroup have been subjected to male-, female- and multiple-choice mating experiments. Out of 8456 crosses conducted, 7185 had successful matings. The overall impression is that mating is far from random amongst these six closely related races of the nasuta-albomicans complex. The males of D. n. albomicans, Cytorace 1 and Cytorace 4 in male-choice, the females of Cytorace 1 and Cytorace 2 in female-choice, and the males and females of D. n. nasuta, D. n. albomicans, Cytorace 1 and Cytorace 4 against the males and females of Cytorace 2 in multiple-choice experiments, had significantly more homogamic matings than expected. Thus in this study of evolutionary experimentation on raciation under laboratory conditions, we have documented the initiation of preference for conspecific matings among closely related and independently evolving members of the nasuta-albomicans complex of Drosophila.

Incipient sexual isolation in the nasuta-albomicans complex of Drosophila: no-choice experiments.

Drosophila nasuta nasuta and Drosophila nasuta albomicans are cross-fertile races of Drosophila. Hybridization between these races in the laboratory has given rise to new races (Cytoraces), among which karyotypic composition differs from one another and also from those of the parental races. In this study, we search for the evidence of incipient reproductive isolation among the parental races and four Cytoraces by assessing the fraction of no-matings, mating latency and copulation duration in all possible types of homo- and heterogamic crosses (N = 4184). In no-choice conditions, the latency time (time to initiation of copulation) is lower in homogamic crosses than in heterogamic crosses for both parental races and Cytoraces. Latency time and copulation duration are negatively correlated, whereas fraction of no matings is positively correlated with latency time. Thus these six closely related races of the nasuta-albomicans complex show the initiation of the earliest stages of pre-zygotic isolation, manifested as a tendency for matings to be initiated earlier and more often, and for a longer duration, among homogamic rather than heterogamic individuals

Racial divergence in abdominal bristles among parental races and newly evolved cytoraces of nasuta-albomicans complex of Drosophila.

Cytoraces are the products of interracial hybridization between Drosophila nasuta nasuta and D. nasuta albomicans. These races differ from their parents in the chromosome composition, mating preference, certain fitness phenotypes and also a few morphophenotypic traits. Now, these cytoraces are passing through 330 generations. Racial divergence in the 4th and 5th abdominal bristles among the parental races and the newly evolved cytorace 1 and 2 is reported. The results revealed that the parental races have more number of bristles than newly evolved cytoraces. Thus, these cytoraces are evolved/evolving with reduced abdominal bristle number and better fitness.

Patterns of replication in the neo-sex chromosomes of Drosophila nasuta albomicans.

Drosophila nasuta albomicans (with 2n = 6), contains a pair of metacentric neo-sex chromosomes. Phylogenetically these are products of centric fusion between ancestral sex (X, Y) chromosomes and an autosome (chromosome 3). The polytene chromosome complement of males with a neo-X- and neo-Y-chromosomes has revealed asynchrony in replication between the two arms of the neo-sex chromosomes. The arm which represents the ancestral X-chromosome is faster replicating than the arm which represents ancestral autosome. The latter arm of the neo-sex chromosome is synchronous with other autosomes of the complement. We conclude that one arm of the neo-X/Y is still mimicking the features of an autosome while the other arm has the features of a classical X/Y-chromosome. This X-autosome translocation differs from the other evolutionary X-autosome translocations known in certain species of Drosophila.

Pattern of sexual isolation between parental races (Drosophila nasuta nasuta and D.n. albomicans) and the newly evolved races (Cytorace I and II).

D.n. nasuta, D.n. albomicans, Cytorace I and Cytorace II [Chromosoma, 93 (1986) 243] are closely related strains of the nasuta subgroup. Through male choice and female choice experiments, the pattern of sexual isolation if any, among them was analysed. Differential mating preference of males and females of these races suggests that they are passing through the process of anagenesis. Therefore, this, as an evolutionary experiment under laboratory conditions, offers a rare opportunity to witness different pattern and levels of divergence among four cytogentically parsimonious races of Drosophila.