Association between regularity in dapsone (DDS) treatment and development of deformity

The existence of an association between regularity in dapsone intake and the development of deformity was investigated in 5746 leprosy patients under treatment in South India. The incidence of deformity, year by year over a 5-year period, increased significantly with increasing levels of drug collection. The excess incidence in "more regular" patients was significant at all ages and in both sexes in nonlepromatous (N) cases. The same was true in intermediate (N?L) cases except in patients under 15 years of age. The evidence in lepromatous (L) cases was not so consistent. Independent confirmation of the presence of the association was sought through a matched case-control type of analysis with 140 N, 48 N?L, and 81 L cases, matching being undertaken with respect to sex, age, type of leprosy, year of starting treatment, and observation period. This showed that the mean regularity in cases (deformed patients) before the development of deformity was significantly higher than the mean regularity in the corresponding matched controls, the differences being particularly large among the N and N?L types. These findings raise the possibility of a causal link between regular dapsone intake and the development of deformity.     

CT-Cephalometry—A study in Indian population

Determination of obstructive site in obstructive sleep apnoea (OSA) is of paramount importance is planning the management. Cephalometric evaluation of lateral X-rays when combined with clinical assessment and fibreoptic examination of the airway helps in locating the site of obstruction. The usual technique of cephalometry has been modified so as to give a better delineation of the soft tissues. Holding a 2mm card board in the mouth and using barium paste helped in more accurate calculations. Using our technique, various parameters have been quantified and a number of controls were studied and normal range derived. Further improvement in cephalometry has been done by using C.T. cephlometry topogram technique. A topogram is a scan done on a running table top cranio-caudally. Using the topogram technique 38 OSA patients were evaluated for all the parameters. The technique, its advantages over traditional cephalometry and the values obtained in the study are discussed in this paper.     

Approximation of the expected value of the harmonic mean and some applications

Although the harmonic mean (HM) is mentioned in textbooks along with the arithmetic mean (AM) and the geometric mean (GM) as three possible ways of summarizing the information in a set of observations, its appropriateness in some statistical applications is not mentioned in textbooks. During the last 10 y a number of papers were published giving some statistical applications where HM is appropriate and provides a better performance than AM. In the present paper some additional applications of HM are considered. The key result is to find a good approximation to E(H_n), the expectation of the harmonic mean of n observations from a probability distribution. In this paper a second-order approximation to E(H_n) is derived and applied to a number of problems.The harmonic mean H_n of n observations Z₁, …, Z_n drawn from a population is defined byHn=n∑i=1n1Zi.[1]There have been a number of applications of the harmonic mean in recent papers. A more general version of H_n with weights w₁, …, w_n isHn(w)=∑i=1nwi∑i=1nwiZi.[2]where w = (w₁,…,w_n)^T. The harmonic mean H_n is used to provide the average rate in physics and to measure the price ratio in finance as well as the program execution rate in computer engineering. Some statistical applications of the harmonic mean are given in refs. 1–4, among others. H_n(w) has been used in evaluation of the portfolio price-to-earnings ratio value (ref. 5, p. 339) and the signal-to-interference-and-noise ratio (6) among others. The asymptotic properties of H_n including the asymptotic expansion of E(H_n) are investigated in refs. 7 and 8 by either assuming that some moments of 1/Z_i are finite or that Z_i s follow the Poisson distribution. It is noted that recent papers (9, 10) enable one to use saddle-point approximation to give the asymptotic expansion of E(H_n) to any given order of 1/n for some constants c₀, c₁, c₂, …, i.e.,E(Hn)=c0+c1n+c2n2+⋯.[3]However, such methods are not applicable for obtaining the asymptotic expansion of H_n when the first moment of 1/Z_i is infinite. In ref. 3, Z_i s are assumed to follow a uniform distribution in the interval (0,1), i.e., U(0,1), motivated by learning theory. Using the property that the inverse of H_n converges to the stable law, ref. 3 showed thatE(Hn)∼1log(n),[4]where the symbol “∼” means asymptotic equivalence as n → ∞. Our interest in this paper is to determine the second term in the asymptotic expansion of E(H_n) or the general version E(H_n(w)) under more general assumptions on distributions of Z_i s. We show that under mild assumptions,E(Hn)∼1log(n){1+c1log(n)},[5]where the constant c₁ will be given. In addition, we use the approach for obtaining [5] to the case that the first moment of 1/Z_i is finite, motivated by evaluation of the marginal likelihood in ref. 11.     

Simulating osteoarthritis: the effect of the changing thickness of articular cartilage on the kinematics and pathological bone-to-bone contact in a hip joint with femoroacetabular impingement

Femoroacetabular impingement (FAI) is a pathomechanical process by which the human hip can fail. The effect of attenuated cartilage on the kinematics and the pathological bone-to-bone contact of an osteoarthritic hip joint with FAI are still unknown. The current study is aiming to simulate osteoarthritis of a cam-type femoral head with cartilage thinning of varying severity. A three-dimensional model of the left hip joint of a male patient diagnosed with FAI was obtained from preoperative computerised tomography data using density segmentation techniques. The kinematics of FAI was simulated using a finite element method. As the acetabulum and femur came into contact, the penetrations were detected, and the contact constraints were applied according to the penalty constraint enforcement method. The translation and rotation parameters were defined in a single step for each one of three cases: healthy cartilage and 2 mm (one-sided thinning) and 4 mm (two-sided thinning) worn out articular cartilages. The results of the analysis show that thinning of the cartilage at the hip joint adversely affects impingement, as a range of motion decreased with progressive thinning of the articular cartilage. In the presence of attenuated cartilage, equating osteoarthritis, the pathomorphology of the cam lesion, likely determines the extent of damage on the rim of the acetabulum, as well.     

Cerium oxide nanoparticles attenuate monocrotaline induced right ventricular hypertrophy following pulmonary arterial hypertension

Cerium oxide (CeO₂) nanoparticles have been posited to exhibit potent anti-oxidant activity which may allow for the use of these materials in biomedical applications. Herein, we investigate whether CeO₂ nanoparticle administration can diminish right ventricular (RV) hypertrophy following four weeks of monocrotaline (MCT)-induced pulmonary arterial hypertension (PAH). Male Sprague Dawley rats were randomly divided into three groups: control, MCT only (60 mg/kg), or MCT + CeO₂ nanoparticle treatment (60 mg/kg; 0.1 mg/kg). Compared to the control group, the RV weight to body weight ratio was 45% and 22% higher in the MCT and MCT + CeO₂ groups, respectively (p < 0.05). Doppler echocardiography demonstrated that CeO₂ nanoparticle treatment attenuated monocrotaline-induced changes in pulmonary flow and RV wall thickness. Paralleling these changes in cardiac function, CeO₂ nanoparticle treatment also diminished MCT-induced increases in right ventricular (RV) cardiomyocyte cross sectional area, β-myosin heavy chain, fibronectin expression, protein nitrosylation, protein carbonylation and cardiac superoxide levels. These changes with treatment were accompanied by a decrease in the ratio of Bax/Bcl2, diminished caspase-3 activation and reduction in serum inflammatory markers. Taken together, these data suggest that CeO₂ nanoparticle administration may attenuate the hypertrophic response of the heart following PAH.     

Gender-specific association of TSNAX/DISC1 locus for schizophrenia and bipolar affective disorder in South Indian population

Genetic association studies have implicated the TSNAX/DISC1 (disrupted in schizophrenia 1) in schizophrenia (SCZ), bipolar affective disorder (BPAD) and major depression. This study was performed to assess the possible involvement of TSNAX/DISC1 locus in the aetiology of BPAD and SCZ in the Southern Indian population. We genotyped seven single nucleotide polymorphism (SNPs) from TSNAX/DISC1 region in 1252 individuals (419 BPAD patients, 408 SCZ patients and 425 controls). Binary logistic regression revealed a nominal association for rs821616 in DISC1 for BPAD and also combined cases of BPAD or SCZ, but after correcting for multiple testing, these results were non-significant. However, significant association was observed with BPAD, as well as combined cases of BPAD or SCZ, within the female subjects for the rs766288 after applying false discovery rate corrections at the 0.05 level. Two-locus analysis showed C-C (rs766288-rs2812393) as a risk combination in BPAD, and G-T (rs2812393-rs821616) as a protective combination in SCZ and combined cases of BPAD or SCZ. Female-specific associations were observed for rs766288-rs2812393, rs766288-rs821616 and rs8212393-rs821616 in two-locus analysis. Our results provide further evidence for sex-dependent effects of the TSNAX/DISC1 locus in the aetiology of SCZ and BPAD.     

A clinical profile of patients with Parkinson's disease and psychosis

Aims:

The aim of the study was to study the clinical profile of the patients with Parkinson''s disease (PD) and psychosis.

Settings and Design:

This was a prospective, cross sectional, hospital-based study done at the Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore, India from September 2009 to January 2011. All patients with PD, diagnosed by United Kingdom PD Society Brain Bank criteria, having with features of psychosis as diagnosed by the neuropsychiatric inventory (NPI) were included. Patients without a caregiver who could validate the patient''s symptoms were excluded.

Results:

A total of 40 patients (5 women, 35 men) with PD with psychosis (mean age: 54.2 ± 11.5 years, mean duration of illness: 6.5 ± 4.5 years, and mean duration of psychosis: 4.3 ± 4.3 years) were included in the study. The Global NPI score was 19.1 ± 11.5. Majority of the patients had pure hallucinations (85%), while the rest had either pure delusions (7.5%) or a combination of delusions and hallucinations (7.5%). In those with hallucinations, visual hallucinations were the commonest (60%) (pure only in 22.5%), followed by auditory (45%), minor hallucinations (45%), and tactile (20%). Only one person reported having olfactory hallucinations (2.5%). Loss of insight was most often observed during the visual hallucinations (52%), followed by tactile (44.4%), auditory (38.9 %), and minor hallucinations (33.3%).

Conclusions:

In patients with PD and psychosis, pure hallucinations are common and visual hallucinations are the commonest among the hallucinations. A large proportion of patients have minor hallucinations, which need to be recognized early for effective and early management. The limitations of the study were small sample size, use of a single scale to assess psychosis and subjective assessment of insight.