Magnetic response in the vicinity of magnetic compensation: a case study in spin ferromagnetic Sm1 - xGdxAl2 intermetallic alloys

A compensated magnetic state in an ideally homogeneous system with long range magnetic order is characterized by a net zero magnetization (M) throughout the sample (macroscopic). In the pristine state of the sample (i.e. with no external field, H = 0), this implies that at the magnetic compensation temperature (Tcomp) we must have M = 0 at H = 0 irrespective of any thermal and magnetic history of the sample and any underlying physics. This simple fact voids the usual identification (and interpretation) of M-H loop parameters at and in the vicinity of magnetic compensation temperature, specifically the coercivity, the remanence, and the exchange bias characteristics. The physics of coercivity and exchange bias continues to be fully relevant, but its manifestation in an M-H loop would get camouflaged at (and near) a magnetic compensation because [Formula: see text] at H = 0. We present an experimental elucidation of the above premise through a case study in the spin ferromagnetic Sm1 - xGdxAl2 alloys [x = 0.01-0.06], where the specimens with x ≤ 0.03 show compensation below the Curie temperature Tc, while those with x ≥ 0.03 have rather small magnetization due to near cancellation of opposing contributions, but are otherwise devoid of compensation. The experiments comprised low field (near zero) as well as high field (70 kOe) magnetization measurements from the paramagnetic state down to 5 K in the ordered regime (Tc ∼ 125 K) and isothermal M-H loop studies on the remnant magnetic state of polycrystalline samples.

Factors influencing blood donations and the rational use of blood

A multicentric quasi-experimental study was conducted in Delhi, from March 2007 to September 2007, on i) the factors which stimulate the donors to donate blood, ii) major barriers and myths associated with blood donation and iii) clinicians perception of the rational use of blood. The study design included a face-to-face survey, with a pre-tested questionnaire paper in two leading blood banks of Delhi and by relevant interviewers from the community and medical fraternity. The sample size was 240-blood donors from two different blood banks and the control group included 100 potential donors from community and 50 clinicians from various hospitals. The data generated was analyzed using excel sheet and Epi-Info software. The study revealed the factors which influence the blood donation included replacement credit and family/peer pressure. Regarding myths and barriers, among potential donors, about a quarter of them felt that it is time consuming, and 20% felt it could lead to sexual impairment or is not rewarding. A total of 10% were not aware about the blood donation while 15% said that donation time was inconvenient. Of the 50 clinicians, a quarter of them were not aware of the rational use of blood.

Comet assay: a prognostic tool for DNA integrity assessment in infertile men opting for assisted reproduction

BACKGROUND & OBJECTIVES

The growing concern on transmission of genetic diseases in assisted reproduction technique (ART) and the lacunae in the conventional semen analysis to accurately predict the semen quality has led to the need for new techniques to identify the best quality sperm that can be used in assisted procreation techniques. This study analyzes the sperm parameters in the context of DNA damage in cytogenetically normal, AZF non deleted infertile men for DNA damage by comet assay.

METHODS

Seventy infertile men and 40 fertile controls were evaluated for the semen quality by conventional semen parameters and the sperms were also analyzed for DNA integrity by comet assay. The patients were classified into oligozoospermic (O), asthenozoospermic (A), teratozoospermic (T), oligoasthenoteratozoospermic (OAT) categories and infertile men with normal semen profile. The extent of DNA damage was assessed by visual scoring method of comets.

RESULTS

Idiopathic infertile men with normal semen profile (n=18) according to conventional method and patients with history of spontaneous abortions and normal semen profile (n=10) had high degree of DNA damage (29 and 47% respectively) as compared to fertile controls (7%). The O, A, T and OAT categories of patients had a variably higher DNA damage load as compared to fertile controls.

INTERPRETATION & CONCLUSION

The normal range and threshold for DNA damage as a predictor of male fertility potential and technique which could assess the sperm DNA damage are necessary to lower the trauma of couples experiencing recurrent spontaneous abortion or failure in ART.

Antioxidant levels in blood and seminal plasma and their impact on sperm parameters in infertile men

Excess reactive oxygen species (ROS) beyond the scavenging capacity of antioxidants leads to DNA damage and oxidation of lipoprotein components at the cellular and subcellular level. The oxidative stress (OS) adversely affects sperm function by altering membrane fluidity, permeability and impairs sperm functional competence. In the present study, the OS status in seminal plasma and blood serum in infertile men and its relationship with spermatozoa parameters have been investigated. Four groups of infertile men viz., oligozoospermic (n = 15), asthenozoospermic (n = 17), teratozoospermic (n = 19), and oligoasthenoteratozoospermic (n = 9), and healthy fertile controls (n = 40) have been analyzed for superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) and malondialdehyde (MDA) in seminal plasma and blood serum. Significant correlation between blood serum SOD and sperm count has been observed in patients (p = 0.018) and controls (p = 0.021). Similarly, significant correlation between blood serum GSH and sperm progressive motility in patients (p = 0.036) and controls (p = 0.029) is observed. The low seminal MDA is associated with increase in sperm progressive motility in patients (p = 0.039) and controls (p = 0.028). Positive correlation is found between increased seminal MDA levels and abnormal sperm morphology in both patients and controls (r = 0.523, p = 0.029; r = 0.612, p = 0.034 respectively). Correlations between blood SOD and sperm count and between blood GSH levels and progressive motility suggest that these can be important biochemical markers in assaying the sperm count and motility. A negative correlation of motility with seminal MDA indicates that sperm membrane lipid peroxidation affects the fluidity and thus mobility of sperm axoneme. This affects functional competence of the sperm and acts like a biological safeguard. The results of the present study suggest the prospects of using the blood serum and seminal plasma antioxidants as a valuable tool to evaluate the sperm reproductive capacity and functional competence.

Mitochondrial ATP synthase inhibition and nitric oxide are involved in muscle weakness that occurs in acute exposure of rats to monocrotophos

Organophosphate poisoning in the context of self-harm is a common medical emergency in Asia. Prolonged muscle weakness is an important but poorly understood cause of morbidity and mortality of the poisoning. This study examined mitochondrial function and its modulation by nitric oxide in muscle weakness of rats exposed to an acute, oral (0.8LD(50)) dose of monocrotophos. Muscle mitochondrial ATP synthase activity was inhibited in the rat in acute exposure to monocrotophos while respiration per se was not affected. This was accompanied by decreased mitochondrial uptake of calcium and increased levels of nitric oxide. Reactive cysteine groups of ATP synthase subunits were reduced in number, which may contribute to decreased enzyme activity. The decrease in ATP synthase activity and reactive cysteine groups of ATP synthase subunits was prevented by treatment of animals with the nitric oxide synthase inhibitor, L-N(G) Nitroarginine methyl ester, at 12 mg/kg body weight for 9 days in drinking water, prior to monocrotophos exposure. This indicated a role for nitric oxide in the process. The alterations in mitochondrial calcium uptake may influence cytosolic calcium levels and contribute to muscle weakness of acute organophosphate exposure.

Oxidative stress and sperm mitochondrial DNA mutation in idiopathic oligoasthenozoospermic men

Physiological function of reactive oxygen species (ROS) has been known since a long, but recently toxic effects of ROS on spermatozoa have gained much importance in male infertility. Mitochondrial DNA (mtDNA) is believed to be both source and target of ROS. mtDNA unlike nuclear DNA is not compactly packed and hence more susceptible to oxidative stress (OS) than nuclear DNA. In the present study, the role of OS in mitochondrial genome changes was studied in men with idiopathic infertility. The study included 33 infertile oligo-asthenozoospermic (OA) men and 30 fertile controls. Semen analyses were performed and OS was measured by estimating the level of malondialdehye (MDA) in the seminal plasma and ROS in the sperm. Sperm mtDNA was sequenced by standard PCR-DNA sequencing protocol for ATPase and nicotinamide adenine dinucleotide dehydrogenase (ND) groups of genes. Sperm count and progressive motility were found to be significantly lower in infertile group than the fertile controls. Semen MDA and ROS levels of infertile group were significantly higher (p<0.0001), when compared to the control group. However, catalase and glutathione peroxidase (GPx) levels were significantly lower in infertile group, compared to controls, but no significant difference in superoxide dismutase (SOD) activity was observed between control and cases. This might be due to higher expression of SOD alone in order to overcome OS in the semen. mtDNA analysis showed significant and high frequency of nucleotide changes in the ATPase (6 and 8), ND (2, 3, 4 and 5) genes of infertile cases compared to the controls. Hence excess ROS and low antioxidant levels in the semen might cause mtDNA mutations and vice versa in OA men that might impair the fertilizing capacity of spermatozoa. Thus, it is important to understand the etiology of mitochondrial genome mutations in idiopathic OA cases for better diagnostic and prognostic value in infertility treatment/assisted reproductive technique.

DNA integrity and semen quality in men with low seminal antioxidant levels

Accurate transmission of information coded in the sperm genome is vital to the pre- and post-natal development of the offspring. Recent advances in reproductive biology have proposed evaluation of sperm DNA integrity as an important assessment tool to infer the presence of DNA strand breaks, numerical abnormalities in sperm chromosome complement, and alterations in the epigenetic regulation of the paternal genome. Oxidative stress (OS), characterized by increased free radicals, may lead to the production of apurine sites, apyrimidine sites, oxidation of nucleotides of sperm genome. This study was performed to assess the impact of OS on DNA integrity in sperms. 52 infertile men [oligozoospermic-13, asthenozoospermic-15, teratozoospermic-19, oligoasthenoteratozoospermic-5] and 20 fertile controls were investigated for products of lipidperoxides as malondialdehyde; antioxidants such as superoxide dismutase, catalase and glutathione in seminal plasma by biochemical methods. DNA integrity of the sperms was analyzed by visual scoring method in which the comets were graded into 4 categories (A-D) on the basis of their tail length indicative of increasing levels of DNA damage. Significant increase in DNA damage (higher number of sperms in group D) in cases (oligozoospermic (O)-20%, asthenozoospermic (A)-24%, teratozoospermic (T)-28%, OAT-43%) as compared to controls (8%) was found. Increased malondialdehyde levels, abnormal sperm morphology and higher DNA damage were observed in the cases. The antioxidants superoxide dismutase, catalase and glutathione had a positive association with sperm count and motility while a negative association with the percentage of dead sperms and abnormal morphology was observed. This study highlights the influence of low antioxidants on sperm genome integrity and indicates sperm DNA integrity as a better and more reliable prognostic tool for infertility evaluation than simple quantitative and morphologic evaluation of spermatozoa.

Role of reactive oxygen species in the pathogenesis of mitochondrial DNA (mtDNA) mutations in male infertility

Infertility affects about 15 per cent married couples half of which may be attributed to men with low sperm motility (asthenozoospermia), low sperm count (oligozoospermia) or abnormal sperm morphology (teratozoospermia). As mitochondria are the energy source for initiation, differentiation and function of the germ cells, mutation in mitochondrial genome can impair the formation of mature spermatozoa. Mutations in mitochondrial genome are identified in patients with fertility problems. However, mitochondria are also both the source and target of reactive oxygen species (ROS). ROS are normally generated at low levels by human spermatozoa in order to perform its physiological function. However, if the generation of these reactive free radicals overwhelm the antioxidant defense system, this can lead to oxidative stress, which is characterized by mitochondrial and nuclear genome damage. So both ROS and mtDNA mutations are considered to be the major aetiological factors in a variety of human diseases including male infertility. Identification of novel mutations in mtDNA of infertile patients with supraphysiological levels of ROS are considered to be important to gain better understanding of the aetiology of idiopathic infertility. Early detection and prompt antioxidant therapy can prevent ROS induced DNA damage. This has far reaching impact if such men opt for assisted reproductive technology (ART)/in vitro fertilization.

Which is the better option: recombinant human PDGF-BB 0.01% gel or standard wound care, in diabetic neuropathic large plantar ulcers off-loaded by a customized contact cast?

This study compares the efficacy of 0.01% rh-PDGF-BB with standard wound care in 20 patients with diabetes mellitus with neuropathic large plantar ulcers off-loaded with modified total contact cast. The incidence, duration and rate of healing were compared. An accelerated rate of healing in rhPDGF group was observed.

Genetic screening in couples experiencing recurrent assisted procreation failure

Infertility is a major health problem affecting about 10-20% of couples in the reproductive age group. Male factor is assumed to be responsible in about 50% cases of infertility. The origin of reduced testicular sperm function is unknown in about 50-70% of cases and for such couples assisted reproduction techniques (ART) are a boon. Male infertility is often due to poor semen quality and may be associated with genetic defects. ART has revolutionized management of infertility and intracytoplasmic sperm injection (ICSI) is the ART procedure of choice in 60-80% cases. Despite major technological advancements and professional expertise in ART, the success rate and carry-home live birth rate of ICSI is low (18-25%). This study was aimed to understand the genetic etiopathology of recurrent ART failure. For this, 110 couples with 3 or more failed ART cycles were recruited. A detailed history was taken and only idiopathic ART failure cases were enrolled for this study. They were subjected to cytogenetic and Yq microdeletion analysis. Genetic abnormalities were detected in 19 couples. Since a large number (18.2%) cases harboured genetic abnormalities, it is important for all couples opting for ART to undergo a thorough genetic analysis to prevent recurrent emotional, physical and financial stress.

Emergence and trends of penicillin non-susceptible Streptococcus pneumoniae in Saudi Arabia and Kuwait - perspective and outstanding issues

For many years in the past Streptococcus pneumoniae was uniformly susceptible to penicillin until the sudden and unexpected emergence of clinical infections caused by penicillin-resistant S. pneumoniae (PRSP) in 1967. Within the following decade, reports of nosocomial and community outbreaks of infections due to PRSP became widespread all over the world. Recent reports suggest that the incidence of resistance rates is rising in many countries although there are geographical variations in the prevalence and patterns of resistance between countries. The problem of antibiotic resistance is further compounded by the emergence of resistance to many beta-lactam antibiotics. The first report of PRSP in Saudi Arabia was in 1991. Barely a year after, PRSP infection was reported in Kuwait in 1992. Since then, studies from various parts of these countries have recorded prevalence rates ranging from 6.2% in Riyadh to 34% in Jeddah and 20% to 56% in neighboring Kuwait. These suggest considerable variation in the prevalence of PRSP in different cities in the Saudi Kingdom and Kuwait. The mechanism of resistance is due to chromosomally mediated alteration of penicillin-binding proteins (PBPs), which are target sites for beta-lactam antibiotics. It would appear that the spread of PRSP strains in Saudi Arabia is driven by the selective pressure created by excessive use and misuse of antimicrobial agents made possible by the easy availability of these agents, often frequently obtainable over the counter. In Kuwait, irrational and misguided use of antibiotics may be the major driving force favoring the spread of PRSP. The serotypes of strains encountered in Saudi Arabia and Kuwait are almost identical, with serotypes 19, 6, 15, 14 and 23 being the most common; together they constitute about 70% of the isolates circulating in these countries. In general, almost 90% of the serotypes included in the 23-polyvalent vaccine are present in the general population. However, a much lower percentage of these serotypes is found in the conjugated vaccines, which are more relevant to our communities. This paper reviews the emergence and the steady increase in the prevalence of penicillin-resistant pneumococcal strains in Saudi Arabia and Kuwait during the last 10 years. It discusses the trends, mechanisms of resistance and factors associated with the emergence, dissemination, and colonization of resistant organisms and suggests options available to clinicians for management of infections due to PRSP.

Bellary, India achieves negligible case fatality due to Japanese encephalitis despite no vaccination: an outbreak investigation in 2004

OBJECTIVE

To confirm the existence of the outbreak of suspected Japanese encephalitis, identify the source, to understand the circumstances due to which the outbreak was taking place and to suggest measures for its control.

METHODS

The team visited Bellary from 4th to 10th Sept, 2004. The team interviewed the key persons and analyzed the records at District Surveillance Unit and Entomological Surveillance Unit and case records of suspected JE cases admitted in Encephalitis ward in Vijay Nagar Institute of Medical Sciences (VIMS). Eco-entomological survey was done in houses and surroundings of 3 randomly selected cases of Encephalitis in rural and urban areas of District Bellary. Their family members and neighbors were also asked for the awareness and presence of disease. Data was analyzed for epidemiological and clinical profiles.

RESULTS

The suspected JE cases were being reported from end of June 2004. The cases were sporadic and out of 34 cases reported to VIMS (till 10th of September), 32 were from Bellary district and 2 were from adjoining Andhra Pradesh. Among these 32, 22 were from Bellary Taluk, which in turn were mainly concentrated (10 were reported) in urban Bellary. The case fatality rate was zero as no death was reported. Entomological surveillance (done by District Surveillance Unit) revealed a high outdoor presence of Culex tritaeniorhynchus as well as an indoor rising density of this mosquito from 2 per man hour catch in January to 22 in the month of August in the affected villages. On the contrary, the investigations on 7th and 8th September revealed high densities of An.subpictus and An. peditaenatus and nil of Culex species in the urban areas. Amplifier host of pigs and water birds were occasionally sighted in the area.

CONCLUSION

A good community awareness of encephalitis, a prompt referral system and a good supportive treatment for the patients and a good surveillance system and response were observed. Very close proximity with amplifying hosts of pigs was avoided by the community, though piggeries were still not very far away (1-3 Km). These may explain the reduction in cases, deaths and disabilities due to this disease in this district over the years. Possibilities of mutant strain which is less virulent and/or a better immune status of at risk population may also need to be explored. The impact of the mass vaccination with SA 14-14-2, imported from China in Bellary during July, 2006 remains to be evaluated. This will further decrease the case load.

Anti-diabetic activity of flowers of Hibiscus rosasinensis

The ethanol extract of flowers of Hibiscus rosasinensis at doses of 250 mg/kg and 500 mg/kg significantly reduced the blood glucose level in both acute (1, 3, 5 h) and sub acute (1, 3, 5, 7 days) treatments.

Epidemiological investigation of an outbreak of chikungunya in hyderabad and nalgonda districts of andhra pradesh, India

After about three decades, Chikungunya infection has re-emerged in India and the first cases were reported in December, 2005. The outbreak has currently affected about 8 states in the country. Although known to be commonly non fatal, since the present outbreak involved a large population, it has been raised as an issue of public health concern and also attracted wide media attention. The clinico-epidemiological and entomological review of the Chikungunya outbreak situation in Hyderabad and Nalgonda Districts of Andhra Pradesh, which started in December 2005, revealed that it is under control. However, preventive efforts need to continue and disease surveillance for early detection of potential outbreaks further strengthening. Given the significantly high House Index, all the three study areas remain at significant risk of outbreaks in the future if appropriate control measures are not put in place. Community support and participation is also crucial for the prevention of future outbreaks and improving the health and well being of population in the districts.

An evaluation of diarrheal diseases and acute respiratory infections control programmes in a Delhi slum

OBJECTIVE

Effective early management at home level and health seeking behavior in case of appearance of danger signs are key strategies in Acute respiratory Infections (ARI) and Acute Diarrheal Diseases (ADD) where majority of episodes are self-limiting and viral in origin. Integrated Management of Childhood illnesses (IMNCI) also envisages that family and community health practices especially health care seeking behaviors are to be improved to reduce childhood morbidity, mortality and cost of admissions to hospitals. Thus, a study was undertaken at an urban slum area--'Gokul Puri' in Delhi, among under-5 children with the aim to assess the magnitudes of ARI and ADD.

METHODS

A Cross-sectional survey was conducted in this urban slum of Trans-Yamuna, covering 1307 under-5 children for five days starting from 9th of August, 2004. Survey team consisted of 14 FETP Participants (WHO Fellows) from India, Nepal, Myanmar, Bhutan and Sri Lanka. A pre-tested, house-hold tally marking form was used to interview the caretakers/mothers. History of episodes of ARI and/or ADD in the last two weeks was asked. Health care practices including use of ORS &home available fluids in diarrhea, continued feeding during diarrhea, awareness of danger signs of ARI &ADD and medical advice sought were asked of those mothers whose children had such an episode.

RESULTS

191 (14.6 %) of 1307 children surveyed, had an attack of ARI in the preceding two wk. The common symptoms of ARI cases were mild running nose (78%), cough (76.4%) and/or fever (45.5%). Only 8 (4%) had fast breathing. One or more danger signs were known to 80% (152/191) of mothers and an equal number (80%) of mothers had sought treatment. ARIs are mostly mild or self limiting but only 16% of caretakers perceived so and doctors also prescribed medicines. The attack rate of Acute Diarrheal Diseases was 7.73% in the study and ADD's annual adjusted morbidity rate was 1.69 episodes per child per year. Though nearly three-fourth of mothers (71.3%) had reported to be seeking medical advice (which is not needed in mild episodes of diarrhea) the ORS use was 38.6%, use of Home available fluids (HAF) was 42% and continued feeding was 50% during the ADD episode and awareness of at least two danger signs was present in 34%.

CONCLUSION

Though aware of danger signs of ARI, care takers were still seeking medical advice for mild cases of ARI and doctors were prescribing drugs. Correct home based management e.g. use of ORS, continued feeding etc. was deficient in the community. Knowledge of danger symptoms was low and medical advice was being sought and drugs were being prescribed for ADD, too.