Physiologically important metal nanoparticles and their toxicity

Nanotechnology has been setting benchmarks for the last two decades, but the origins of this technology reach back to ancient history. Today, nanoparticles of both metallic and non-metallic origin are under research and development for applications in various fields of biology/therapeutics. Physiologically important metals are of concern because they are compatible with the human system in terms of absorption, assimilation, excretion, and side effects. There are several physiologically inorganic metals that are present in the human body with a wide range of biological activities. Some of these metals are magnesium, chromium, manganese, iron, cobalt, copper, zinc, selenium and molybdenum. These metals are synthesized in the form of nanoparticles by different physical and chemical methods. Physiologically important nanoparticles are currently under investigation for their bio-medical applications as well as for therapeutics. Along with the applicative aspects of nanoparticles, another domain that is of great concern is the risk assessment of these nanoparticles to avoid unnecessary hazards. It has been seen that these nanoparticles have been shown to possess toxicity in biological systems. Conventional physical and chemical methods of metal nanoparticle synthesis may be one possible reason for nanoparticle toxicity that can be overcome by synthesis of nanoparticles from biological sources. This review is an attempt to establish metal nanoparticles of physiological importance to be the best candidates for future nanotechnological tools and medicines, owing to the acceptability and safety in the human body. This can only be successful if these particles are synthesized with a better biocompatibility and low or no toxicity.

In vivo interaction of gold nanoparticles after acute and chronic exposures in experimental animal models

With emerging use of gold nanopaticles (GNP) in biomedical science now concern lies upon the fact that how this nonanparticles interact with biological systems both in vivo and in vitro. In this study effects of GNP (50 nm) were investigated in animal models after acute and chronic exposure. For acute studies GNP was administered intravenously at three doses and urine and blood samples were collected for urinary and haematological analysis at regular time intervals. For chronic studies GNP was administered intra-peritoneally at two dose levels and urine, blood, serum and tissue samples were collected for urinary, haematological, serum biochemical and histo-pathological analysis at regular intervals. Acute exposure revealed significant increase in WBC count at all the three dose levels and significant dose-dependent increase in RBC count and Hb%. Chronic exposure at 2 mg/kg dose level showed high toxicity. Significant changes in physical, morphological, WBC count and Hb% were observed after chronic exposure for multiple days. Histo-pathological studies indicated detrimental tissue histological changes in chronic animal models. Therefore, the above studies indicate that both acute and chronic GNP exposure exhibits potential physiological changes within animal system.

Nanoparticle-conjugated animal venom-toxins and their possible therapeutic potential

Nano-medical approaches to develop drugs have attracted much attention in different arenas to design nanoparticle conjugates for better efficacy of the potential bio-molecules. A group of promising candidates of this category would be venom-toxins of animal origin of potential medicinal value. Traditional systems of medicine as well as folklores mention the use of venom-toxins for the treatment of various diseases. Research has led to scientific validation of medicinal applications of venoms-toxins and many active constituents derived from venoms-toxins are already in clinical use or under clinical trial. Nanomedicine is an emerging field of medicine where nanotechnology is used to develop molecules of nano-scale dimension, so that these molecules can be taken up by the cells more easily and have better efficacy, as compared to large molecules that may tend to get eliminated. This review will focus on some of the potential venoms and toxins along with nanoparticle conjugated venom-toxins of snakes, amphibians, scorpions and bees, etc., for possible therapeutic clues against emerging diseases.

Loss of HtrA2/Omi activity in non-neuronal tissues of adult mice causes premature aging

mnd2 mice die prematurely as a result of neurodegeneration 30-40 days after birth due to loss of the enzymatic activity of the mitochondrial quality control protease HtrA2/Omi. Here, we show that transgenic expression of human HtrA2/Omi in the central nervous system of mnd2 mice rescues them from neurodegeneration and prevents their premature death. Interestingly, adult transgenic mnd2 mice develop accelerated aging phenotypes, such as premature weight loss, hair loss, reduced fertility, curvature of the spine, heart enlargement, increased autophagy, and death by 12-17 months of age. These mice also have elevated levels of clonally expanded mitochondrial DNA (mtDNA) deletions in their tissues. Our results provide direct genetic evidence linking mitochondrial protein quality control to mtDNA deletions and aging in mammals.

Clinical manifestation of Hurler syndrome in a 7 year old child

Mucopolysaccharidosis type I (MPS I H, Hurler syndrome) is a rare autosomal recessive inborn deficiency in the metabolism of glycosaminoglycans (GAGs) heparan sulfate and dermatan sulfate, resulting from deficiency of Alpha-L-iduronidase enzyme. This condition is characterized by accumulation of incompletely degraded glycosaminoglycans into various organs of body, which leads to impairment of organs and body functions. Such children appear nearly normal at birth; however, if left untreated, show a progressive mental and physical deterioration leading to death due to cardiorespiratory failure before the second decade of life. Pedodontists have a role for early diagnosis, rendering corrective and preventive treatment to the developing dentition, and referring the patient to the concerned specialities. An interesting case of a seven year old boy with a combination of skeletal, neurological, ophthalmologic, oro-dental and radiological findings of this diverse and devastating clinical entity with MPS I-(Hurler syndrome) has been presented here in this case report.

Hepatoprotective activity of the edible snail (Bellamia bengalensis) flesh extract in carbon tetrachloride induced hepatotoxicity in rats

ETHNOPHARMACOLOGICAL RELEVANCE

In the folk-traditional medicine, snails were used to purify blood, boost immune system, prevent conjunctivitis and to treat liver problems.

OBJECTIVES

To evaluate the hepatoprotective activity of the edible snail (Bellamia bengalensis) flesh extract in male Wistar rats treated with carbon tetrachloride as an hepatotoxicant.

MATERIALS AND METHODS

Live adult Bellamia bengalensis was collected commercially from the Kolkata market. Aqueous flesh extract (BBE) was prepared in 0.9% saline and expressed in terms of wet weight basis. The aqueous flesh extract was administered orally (1, 2 g kg(-1)day(-1)) to male rats for 12 days. Liv52 was used as positive control. 24h after administration of extract, the rats were given a single oral dose of CCl(4) (1.25 ml kg(-1)), except vehicle control rats. After 24h of CCl(4) administration, all the animals were sacrificed to collect the blood and liver tissue.

RESULTS

BBE (1 and 2 g kg(-1)day(-1), p.o.×12 days) significantly prevented CCl(4) induced elevation of SGOT, SGPT, γGT, ACP, ALP, bilirubin, LDH and CCl(4) induced decrease in total protein, triglyceride level in male Wistar rats. BBE treated rat liver anti-oxidant parameters (LPO, SOD, GSH, CAT, GPx) were significantly antagonized for the pro-oxidant effect of CCl(4). Histopathological studies also supported the protective effect of BBE.

CONCLUSION

This study validated the folk and traditional use of snail in liver disorder through CCl(4)-induced rat experimental model.

Syntaxin 3B is essential for the exocytosis of synaptic vesicles in ribbon synapses of the retina

Ribbon synapses of the vertebrate retina are specialized synapses that release neurotransmitter by synaptic vesicle exocytosis in a manner that is proportional to the level of depolarization of the cell. This release property is different from conventional neurons, in which the release of neurotransmitter occurs as a short-lived burst triggered by an action potential. Synaptic vesicle exocytosis is a calcium regulated process that is dependent on a set of interacting synaptic proteins that form the so-called SNARE (soluble N-ethylmaleimide sensitive factor attachment protein receptor) complex. Syntaxin 3B has been identified as a specialized SNARE molecule in ribbon synapses of the rodent retina. However, the best physiologically-characterized neuron that forms ribbon-style synapses is the rod-dominant or Mb1 bipolar cell of the goldfish retina. We report here the molecular characterization of syntaxin 3B from the goldfish retina. Using a combination of reverse transcription (RT) polymerase chain reaction (PCR) and immunostaining with a specific antibody, we show that syntaxin 3B is highly enriched in the plasma membrane of bipolar cell synaptic terminals of the goldfish retina. Using membrane capacitance measurements we demonstrate that a peptide derived from goldfish syntaxin 3B inhibits synaptic vesicle exocytosis. These experiments demonstrate that syntaxin 3B is an important factor for synaptic vesicle exocytosis in ribbon synapses of the vertebrate retina.

A comparative study of cardiac dysautonomia in autosomal dominant spinocerebellar ataxias and idiopathic sporadic ataxias

OBJECTIVES

Comparative evaluation of cardiac dysautonomia in spinocerebellar ataxias (SCA) and idiopathic sporadic ataxias (IA) not fulfilling the criteria of multiple system atrophy.

MATERIAL AND METHODS

Cardiac autonomic functions were evaluated in 14 SCA (SCA1 = 6, SCA2 = 5 and SCA3 = 3) and 10 IA patients, comparable for age, age at onset, duration and severity of illness. The results were categorized as early, definitive, or severe autonomic involvement (EI, DI and SI respectively) based on the degree of abnormalities on tests of parasympathetic and sympathetic pathways.

RESULTS

Cardiac autonomic dysfunction was present in all (EI = 25.0%, DI = 41.7% and SI = 33.3%), parasympathetic dysfunction being an early feature. SI was most often present in SCA3 (100%), followed by those with SCA1 (66.7%), and SCA2 (20%) and none in IA.

CONCLUSIONS

Cardiac dysautonomia was common in both SCA and IA, although the severity was greater in SCA. Among SCAs, the severity was greatest in SCA3, followed by SCA2 and least in SCA1.

Would compliance with cancer care standards improve survival for breast, colorectal and lung cancers?

OBJECTIVE

To investigate whether cancer service standards are associated with survival for breast, colorectal and lung cancers at population level.

METHODS

Standards of hospital cancer services in England, measured in 2001, were aggregated for 30 cancer networks covering populations of between 500 000 and 3 million people, and compared with 1-year and 5-year relative cancer survival for the incident period 1996-2001, using rank correlation.

RESULTS

Relative survival and the cancer standards each showed statistically significant differences across cancer networks. For tumour-specific services, the total score of 35 standards was associated with longer relative survival for both colorectal and lung cancers (p<0.05), but not breast cancer, while colorectal cancer survival was strongly (p<0.01) associated with the specific standard "written agreement describing referral guidelines", and lung cancer (p<0.05) with two other guideline standards. There were also associations of longer survival with two measures of nursing staff specialist qualifications. Compliance with general standards for cancer services was not associated with survival for breast cancer, and showed only borderline (p<0.1) associations for colo-rectal cancer, while some standards on medical and management lead staff were significantly associated (p<0.05) with poorer survival for lung cancer. Overall, compliance with standards for hospital pathology and radiology services also showed no associations with survival.

CONCLUSION

This study suggests that compliance with some clinical service standards, such as guidelines, could contribute to better survival at population level, while more general organisational aspects of cancer services may not directly improve survival.