Taurine can Decrease Phosphorylated Tau Protein Levels in Alzheimer's Model Rats' Brains

Background Microtubule formation is a dynamic process and Tau proteins promote the assembly of tubulin monomers into microtubules. Hyperphosphorylation of some amino acids in tau proteins causes neuron starvation and finally cell death. Taurine is found in the brain and has neuroprotective effects. Objective Since the protective and therapeutic effects of Taurine on phosphorylated tau proteins level in the cerebellum and prefrontal cortex of rats induced by scopolamine have not been studied, we examined these effects. Method Adult male Wistar rats were randomly distributed into nine groups. For two weeks, Taurine-treated rats received different doses of Taurine (25, 50, and 100 mg/kg/ day) before or after scopolamine injection. The phosphorylated tau protein level in the cerebellum and prefrontal cortex was determined by the enzyme-linked immunosorbent assay (ELISA) technique. Result Pretreatment with three doses of Taurine significantly decreased the phosphorylated tau protein level that increased by scopolamine in the prefrontal cortex (p < 0.001), as well as the cerebellum (p < 0.001). Moreover, high-dose administration of Taurine (100 mg/kg/day) after scopolamine injection significantly decreased phosphorylated tau protein level in the cerebellum (p < 0.01), as well as the prefrontal cortex (p < 0.05). However, there was not any significant change in the level of phosphorylated tau protein after Taurine treatment (25 and 50 mg/kg/day) in the cerebellum and prefrontal cortex. Conclusion It can be concluded that Taurine could attenuate the increase in phosphorylated tau protein induced by scopolamine in the brain of rats and usage of Taurine as a pretreatment complement could be more useful in the protection of neurons.

Effects of hCG on reduced numbers of hCG receptors in the prefrontal cortex and cerebellum of rat models of Alzheimer's disease

Age-associated changes in the levels of luteinizing hormone and human chorionic gonadotropin (hCG) are potential risk factors for Alzheimer's disease (AD); hCG concentration is related to the incidence of AD. The highest density of hCG receptors is in zones of the brain that are vulnerable to AD and streptozotocin (STZ) can decrease the density of this receptor. We investigated the effects of different doses of hCG on hCG receptor density in the prefrontal cortex and cerebellum in a rat model of STZ-induced AD. AD was induced by intracerebroventricular injection of 3 mg/kg STZ. The resulting AD rats were treated for 3 days with 50, 100 or 200 IU/200 μl hCG, or with saline as a control. Sections of prefrontal cortex and cerebellum were stained immunohistochemically and hCG receptor-immunoreactive (ir) neurons were counted. STZ injected into the lateral ventricles of rat brains reduced the density of hCG receptor-ir neurons in the prefrontal cortex and cerebellum. hCG administration resulted in a significant dose-dependent increase in the number of hCG receptor-ir neurons in the prefrontal cortex and cerebellum. The maximum increase in the number of receptors occurred following the 200 IU dose of hCG. Administration of hCG ameliorated the lowered density of hCG receptor-ir neurons in the cerebellum and prefrontal cortex in STZ-induced AD rats.

Computational studies on the interactions of glycine amino acid with graphene, h-BN and h-SiC monolayers

In the present work, the adsorption of glycine amino acid and its zwitterionic form onto three different hexagonal sheets, namely graphene, boron-nitride (h-BN) and silicon carbide (h-SiC), has been investigated within the framework of density functional theory (DFT) calculations.

Levodopa medication improves incidental sequence learning in Parkinson's disease

Empirical evidence suggests that levodopa medication used to treat the motor symptoms of Parkinson's disease (PD) may either improve, impair or not affect specific cognitive processes. This evidence led to the 'dopamine overdose' hypothesis that levodopa medication impairs performance on cognitive tasks if they recruit fronto-striatal circuits which are not yet dopamine-depleted in early PD and as a result the medication leads to an excess of dopamine. This hypothesis has been supported for various learning tasks including conditional associative learning, reversal learning, classification learning and intentional deterministic sequence learning, on all of which PD patients demonstrated significantly worse performance when tested on relative to off dopamine medication. Incidental sequence learning is impaired in PD, but how such learning is affected by dopaminergic therapy remains undetermined. The aim of the current study was to investigate the effect of dopaminergic medication on incidental sequence learning in PD. We used a probabilistic serial reaction time task (SRTT), a sequence learning paradigm considered to make the sequence less apparent and more likely to be learned incidentally rather than intentionally. We compared learning by the same group of PD patients (n=15) on two separate occasions following oral administration of levodopa medication (on state) and after overnight withdrawal of medication (off state). Our results demonstrate for the first time that levodopa medication enhances incidental learning of a probabilistic sequence on the serial reaction time task in PD. However, neither group significantly differed from performance of a control group without a neurological disease, which indicates the importance of within group comparisons for identifying deficits. Levodopa medication enhanced incidental learning by patients with PD on a probabilistic sequence learning paradigm even though the patients were not aware of the existence of the sequence or their acquired knowledge. The results suggest a role in acquiring incidental motor sequence learning for dorsal striatal areas strongly affected by dopamine depletion in early PD.

Synthesis of activated carbon/polyaniline nanocomposites for enhanced CO2 adsorption

A new insight to investigate the potential applicability of different nanostructures of a PANI composite with activated carbon for CO₂ adsorption.

Optimization of production conditions for synthesis of chemically activated carbon produced from pine cone using response surface methodology for CO2 adsorption

A new insight to the production optimization of activated carbon from pine cone using RSM methodology for CO₂ adsorption.

Trends of amino acid adsorption onto graphene and graphene oxide surfaces: a dispersion corrected DFT study

First-principle calculations based on DFT were performed to investigate the adsorption properties of amino acids onto graphene surfaces.

A Longitudinal Follow-up Study of Depression, Disability, and Body Concept in Torticollis

Changes in depression, disability, body concept, and severity of head deviation were examined in a sample of 67 patients with idiopathic torticollis, who were reassessed 2 years after taking part in an initial study (before the use of botulinum toxin injections). Over the follow-up period, torticollis was unchanged in 41·8%, had improved in 26·9% and deteriorated in 31·3% of cases. The overall levels of depression, disability, and body concept across the two occasions did not change. Changes in the clinical severity of torticollis over the follow-up period had a significant effect on psychological adjustment. Those whose torticollis improved were less depressed and disabled and a had a more positive body concept compared to the patients whose torticollis had worsened. Measures of illness severity had stronger associations with measures of psychological adjustment at follow-up than at the time of initial study. Longer duration of torticollis was associated with larger increases in depression and disability during the 2 years of follow-up. The results suggest that the experience of depression, disability, and negative body concept in a proportion of torticollis sufferers is a reaction to the neurological illness. A minority of the patients who remain chronically depressed are primary candidates for therapeutic intervention aiming at improving their adjustment to the illness.

Contact with a nurse practitioner: a short-term evaluation study in Parkinson's disease and dystonia

Forty patients with Parkinson's disease and 24 patients with dystonia took part in a study aiming to assess the value of access to and contact with a nurse practitioner over a 6 month period. Patients in each group were randomly allocated to "intervention" or "control" groups, which were matched on important variables. All patients completed a set of questionnaires relating to psychosocial function at two time points separated by 6 months. In the intervening period, those allocated to the "intervention" group received two home visits and five telephone calls from the nurse practitioner. This contact was not provided to the "control" group. The nurse practitioner had a major impact on the provision of information and the facilitation of referral to other health-care agencies. The results of an independent assessment indicated that the patients in the "intervention" programme had found access to and contact with a nurse practitioner of great value. In contrast, the results of the questionnaire assessment did not reveal any statistically significant change in psychosocial functioning from the first to the second assessment for either the "intervention" or "control" groups. The lack of change in the questionnaire measures is discussed in terms of possible sampling bias and the duration of intervention and follow-up. Recommendations are made for future studies, and for the possible provision of clinical services.

Conversion "v" profiles in torticollis

The assumption that spasmodic torticollis represents a conversion reaction was examined by evaluating profiles of 61 patients on the hypochondriasis, depression, and hysteria scales of the Minnesota Multiphasic Personality Inventory. Thirty-six per cent of the sample had normal profiles. A conversion "V" profile with scores above 70 was found in a minority (9%) of the patients. The profile of the majority of the group was characterized by the presence of mild depression. It was concluded that a personality profile suggestive of conversion reaction is not typical of patients with spasmodic torticollis.

Body concept, disability, and depression in patients with spasmodic torticollis

Eighty-five patients with idiopathic spasmodic torticollis were compared with an equally chronic group of 49 cervical spondylosis sufferers in terms of body concept, depression, and disability. The torticollis patients were significantly more depressed and disabled and had a more negative body concept. Depression had different determinants in the two groups. Extent of disfigurement was a major predictor of depression in torticollis. Neuroticism accounted for the greatest proportion of the variance of depression in cervical spondylosis.

Female rat hippocampal cell density after conditioned place preference

The hippocampus is important for learning tasks, such as conditioned place preference (CPP), which is widely used as a model for studying the reinforcing effects of drugs with dependence liability. Long-term opiate use may produce maladaptive plasticity in the brain structures involved in learning and memory, such as the hippocampus. We investigated the phenomenon of conditioning with morphine on the cell density of female rat hippocampus. Forty-eight female Wistar rats weighing on average 200-250 g were used. Rats were distributed into eight groups. Experimental groups received morphine daily (three days) at different doses (2.5, 5, 7.5 mg/kg) and the control-saline group received normal saline (1 ml/kg), and then the CPP test was performed. Three sham groups received only different doses (2.5, 5, 7.5 mg/kg) of morphine without CPP test. Forty-eight hours after behavioural testing animals were decapitated under chloroform anaesthesia and their brains were fixed, and after tissue processing, slices were stained with cresyl violet for neurons and phosphotungstic acid haematoxylin for astrocytes. The maximum response was obtained with 5 mg/kg of morphine. The density of neurons in CA1 and CA3 areas of hippocampus after injection of morphine and CPP was decreased. The number of astrocytes in different areas of hippocampus was increased after injection of morphine and CPP. It seems that the effective dose was 5 mg/kg, as it led to the CPP. We concluded that both injection of mor phine and CPP can decrease the density of neurons and also increase the number of astrocytes in the rat hippocampus.

The effect of MDMA-induced anxiety on neuronal apoptosis in adult male rats' hippocampus

Ecstasy or MDMA as a psychoactive drug and hallucinogen is considered one of the most commonly used drugs in the world. This psychotropic substance is discussed both as sexually stimulating and reducing fear and anxiety. Amphetamines also destroy neurons in some brain areas. The aim of this study was to investigate the effects of MDMA on anxiety and apoptosis of hippocampal neurons. Forty-two male Wistar rats of mean weight 200-220 g were used and distributed into six groups [control, control-saline, and experimental groups (1.25, 2.5, 5, 10 mg/kg)]. Rats in experimental groups received MDMA at different doses for seven days by intraperitoneal injection and the control-saline group received saline (1 ml/kg); anxiety was then investigated by plus-maze test. Forty-eight hours after behavioural testing brains were taken from animals and fixed, and after tissue processing, slices were stained with TUNEL kit for apoptotic cells. The area densities of apoptotic neurons were measured throughout the hippocampus and compared in all groups (P < 0.05). Physiological studies showed that 1.25 mg/kg and 2.5 mg/kg doses caused anti-anxiety behaviour and 5 and 10 mg/kg doses of MDMA caused anxietylike behaviour. Moreover, our histological study showed that ecstasy increased apoptotic cell numbers and the highest increase was observed with the 10 mg/kg dose of MDMA. We concluded that MDMA can cause different responses of anxiety-like behaviour in different doses. This phenomenon causes a different ratio of apoptosis in hippocampal formation. Reduction of anxiety-like behaviour induced by the 2.5 mg/kg dose of MDMA can control apoptosis.

Gender differences in quality of life following subthalamic stimulation for Parkinson's disease

OBJECTIVES

Surveys of subthalamic nucleus (STN) deep brain stimulation (DBS) for Parkinson's disease (PD) have shown that this procedure is roughly twice more common in men than in women. Here, we investigate possible differences between women and men undergoing STN DBS, with respect to health-related quality of life.

MATERIALS AND METHODS

Forty-nine consecutive patients (18 women) received STN DBS. The impact of PD and its surgical treatment was compared between women and men, before and at mean of 19 ± 11 months after surgery, using the Unified Parkinson Disease Rating Scale (UPDRS) and the Parkinson's Disease Questionnaire-39 (PDQ-39).

RESULTS

Duration of disease at surgery and off-medication scores of the motor part of the UPDRS were similar in women and men. At baseline, women had lower doses of dopaminergic medication than men, experienced more disability due to dyskinesias, had more sensory symptoms and perceived more difficulties in mobility. Following DBS, both men and women showed equal and significant (P < 0.001) improvement in off-medication scores on the UPDRS III. On the PDQ-39, women expressed improvement in ADL to a greater extent than men. Moreover, women but not men showed a positive effect on mobility, stigma and cognition as well as on the summary score of PDQ-39.

CONCLUSIONS

Although STN DBS results in equal degree of motor improvement between women and men, health-related quality of life seems to improve to a greater extent in women.

Willed action and its impairments

Actions are goal-directed behaviours that usually involve movem ent. There is evidence that intentional self-generated actions (willed actions) are controlled differently from routine, stereotyped actions that are externally triggered by environmental stimuli. We review evidence from investigations using positron emission tomography (PET), recordings of movement-related cortical potentials (MRCPs) or transcranial magnetic stimulation (TMS), and conclude that willed actions are controlled by a network of frontal cortical (dorsolateral prefrontal cortex, supplementary motor area, anterior cingulate) and subcortical (thalamus and basal ganglia) areas. We also consider evidence suggesting that some of the cognitive and motor deficits of patients with frontal lesions, Parkinson's disease, or schizophrenia as well as apathy and abulia and rarer phenomena such as primary obsessional slowness can be considered as reflecting im pairment of willed actions. We propose that the concept of a willed action system based on the frontostriatal circuits provides a useful framework for integrating the cognitive, motor, and motivational deficits found in these disorders. Problems remaining to be resolved include: identification of the component processes of willed actions; the specific and differential role played by each of the frontal cortical and subcortical areas in the control of willed actions; the specific mechanisms of impairm ent of willed actions in Parkinson's disease, schizophrenia, and frontal damage; and the precise role of the neurotransmitter dopamine in the willed action system.

On the nature of fear of falling in Parkinson's disease

In the elderly, fear of falling (FoF) can lead to activity restriction and affect quality of life (QoL). Our aim was to identify the characteristics of FoF in Parkinson's disease and assess its impact on QoL. We assessed FoF in 130 patients with Parkinson’s disease (PD) on scales measuring perceived self-efficacy in performing a range of activities (FES), perceived consequences of falling (CoF), and activity avoidance (SAFFE). A significant difference was found in FoF between PD patients who had previously fallen and those who had not and between frequent and infrequent fallers. Patient-rated disability significantly influenced FoF. Difficulty in rising from a chair, difficulty turning, start hesitation, festination, loss of balance, and shuffling were the specific mobility problems which were associated with greater FoF in PD. Disability was the main predictor of FoF, additionally depression predicted perceived consequences of falling, while anxiety predicted activity avoidance. The FoF measures explained 65% of the variance of QoL in PD, highlighting the clinical importance of FoF. These results have implications for the clinical management of FoF in PD.

MRI-guided STN DBS in Parkinson's disease without microelectrode recording: efficacy and safety

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is a commonly employed therapeutic procedure for patients with Parkinson's disease uncontrolled by medical therapies. This series describes the outcomes of 79 consecutive patients that underwent bilateral STN DBS at the National Hospital for Neurology and Neurosurgery between November 2002 and November 2008 using an MRI-guided surgical technique without microelectrode recording. Patients underwent immediate postoperative stereotactic MR imaging. The mean (SD) error in electrode placement was 1.3 (0.6)&emsp14;mm. There were no haemorrhagic complications. At a median follow-up period of 12&emsp14;months, there was a mean improvement in the off-medication motor part of the Unified Parkinson's Disease Rating Scale (UPDRS III) of 27.7 points (SD 13.8) equivalent to a mean improvement of 52% (p<0.0001). In addition, there were significant improvements in dyskinesia duration, disability and pain, with a mean reduction in on-medication dyskinesia severity (sum of dyskinesia duration, disability and pain from UPDRS IV) from 3.15 (SD 2.33) pre-operatively, to 1.56 (SD 1.92) post-operatively (p=0.0001). Quality of life improved by a mean of 5.5 points (median 7.9 points, SD 17.3) on the Parkinson's disease Questionnaire 39 summary index. This series confirms that image-guided STN DBS without microelectrode recording can lead to substantial improvements in motor disability of well-selected PD patients with accompanying improvements in quality of life and most importantly, with very low morbidity.

Doxorubicin-loaded albumin nanoparticles: formulation and characterization

The purpose of the present study was to develop Doxorubicin (Dox) loaded albumin nanoparticles for regional drug release in solid tumours. Bovine serum albumin nanoparticles were prepared by coacervation method. The nanoparticles were characterized using various techniques: Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC), Dynamic Light Scattering (DLS) technique and Laser Doppler Electrophoresis (LDE) method. The entrapment of Dox in albumin nanoparticles also found out and in vitro release of drug was studied. The results show that the size of albumin nanoparticles increases from Z average of 67 nm to 98 and 106 nm for two different methods; A and B of drug loading, respectively. The SEM results confirm the spherical shape of nanoparticles which made at 4 degrees C. The results show that the size of nanoparticles decreases by decreasing temperature in their production process.

Stress among medical students of Gorgan (South East of Caspian Sea), Iran

OBJECTIVE

This study aims to estimate the prevalence of psychological stress and association between the levels of stress and study variables among Gorgan medical students.

MATERIALS AND METHODS

All three year medical students (129 basic sciences students) in Gorgan Faculty of Medicine, Golestan University of Medical Sciences, were asked to complete the Kessler 10 questionnaire.

RESULTS

The findings showed mild, moderate and severe stress among 26.22%, 20.50% and 14.75% study subjects. 39.35% of medical students had no stress. There was statistically significant association between year of study and stress levels (p= 0.040).

CONCLUSION

The results indicate that there is a decrease in the psychological health of first year medical students. Provided that stress management courses are organised by medical schools, when the students arrive, they will cope up with the stress in coming years. These courses may reduce the negative effects of stress on medical students. By providing such courses and reducing stress level, medical students may improve their medical education.

The effect of Urtica dioica extract on the number of astrocytes in the dentate gyrus of diabetic rats

Diabetes mellitus is associated with cerebral alterations in both human and animal models of the disease. These alterations include abnormal expression of hypothalamic neuropeptides and hippocampal astrogliosis. Urtica dioica (Nettle) is among several species listed for their use against diabetes in folk medicine. The aim of this study was the evaluation of the astrocyte number in the dentate gyrus of diabetic rats after treatment with nettle. A total of 21 male albino Wistar rats were used in the present study. The animals were divided into three groups: control, nettle-untreated diabetic, and nettle treated diabetic. Hyperglycaemia was induced by streptozotocin (80 mg/kg) in the animals of the diabetic and treatment groups. One week after injection of the streptozotocin, the animals in the treatment group received a hydroalcoholic extract of Urtica dioica (100 mg/kg/day) for 4 weeks intraperitoneally. After a 5-week survival period, all the rats were sacrificed and coronal sections were taken from the dorsal hippocampal formation of the right cerebral hemispheres. The area densities of the astrocytes were measured and compared between the three groups (p < 0.05). The number of astrocytes increased in the diabetic rats (24.06 +/- 9.57) compared with the controls (17.52 +/- 6.66). The densities in the treated rats (19.50 +/- 6.16) were lower than in the diabetic rats. Furthermore, the control and treated rats showed similar densities. We concluded that U. dioica extract helped compensate for astrocytes in the treatment rats dentate gyrus in comparison with diabetic rats.

The effect of ethnicity on facial anthropometry in Northern Iran

INTRODUCTION

The evaluation and measurement of human body dimensions are achieved by physical anthropometry. Cephalometery is a branch of anthropometry science in which the head and face anatomical dimensions are measured. This research was conducted in view of the importance of anthropometric indices of the face in forensic medicine, surgery, paediatrics and medical imaging.

METHODS

This descriptive and cross-sectional study was set up to determine and compare the face shapes in Fars and Turkman ethnic groups of 808 normal 17- to 20-year-old males and females in Gorgon, North Iran (Fars group 407, male 200 and female 207; Turkman group 401, male 198 and female 203). The length and width of faces were determined by using classic cephalometery technique with Martin spreading callipers, and the shape of faces in the ethnic group of Fars and Turkman in both sexes was compared.

RESULTS

The dominant type of face shape in both the native Fars and Turkman females was euryprosopic (37.7 and 51.7 percent, respectively). The dominant type of face shape in the native Fars and Turkman males was mesoprosopic (44 and 38.4 percent, respectively).

CONCLUSION

This study determined the possible effect of ethnicity on the diversity of face shapes in young males and females in this region.

The granule cell density of the dentate gyrus following administration of Urtica dioica extract to young diabetic rats

Urtica dioica L. Stinging nettle has long been known worldwide as a medicinal plant. To study the benefits of the nettle in diabetic encephalopathy, the granule cell density of the dentate gyrus of diabetic rats was studied following administration of Urtica dioica extract. A total of 24 male albino Wistar rats were allocated equally to normal, diabetic, preventive and treatment groups. Hyperglycaemia was induced by streptozotocin (80 mg/kg) in the animals of the diabetic and treatment groups. One week after injection of the streptozotocin the animals in the treatment group received a hydroalcoholic extract of Urtica dioica (100 mg/kg/day) for 4 weeks intraperitoneally. The rats of the preventive group received hydroalcoholic extract of U. dioica (100 mg/kg/day) IP for the first 5 days and an injection of streptozotocin (80 mg/kg) on the 6th day. After 5 weeks of study all the rats were sacrificed and coronal sections were taken from the dorsal hippocampal formation of the right cerebral hemispheres and stained with cresyl violet. The area densities of the granule cells were measured and compared in the four groups. The density was lower in the diabetic rats compared with the controls (p > 0.05). The preventive group showed lower cell density than the controls (p > 0.05). The densities in the treated rats were higher than in the diabetic rats (p > 0.05). Furthermore, the control and treated rats showed similar densities (p > 0.05). It seems that U. dioica extract can help compensate for granule cell loss in the diabetic rat dentate gyrus, which can ameliorate cognitive impairment in diabetes. However, preventive use of the extract showed no significant benefit.

The effect of spatial learning on the number of astrocytes in the CA3 subfield of the rat hippocampus

INTRODUCTION

Astrocytes play an important role in the hippocampus, probably in memory and learning. The aim of this study was to evaluate the number of astrocytes in the CA3 subfield of the rat hippocampus after spatial learning using the Morris water maze with reference and working memory methods.

METHODS

45 male albino wistar rats were divided into three groups, with 15 rats in the control group and 15 rats in each of the other two groups. The two study groups of rats underwent spatial learning using the Morris water maze, with one group trained using the reference memory and the other, the working memory technique, respectively. After histological processing, the slides of the brains were stained with the phosphotanguestic acid haematoxylin staining method for detection of the astrocytes.

RESULTS

There was a significant difference in the number of astrocytes in the CA3 area between the control and reference memory groups. The difference between control and working memory groups was significant as well. Additionally, when comparing the two learning groups, we also found significant differences between them.

CONCLUSION

The number of astrocytes increased due to spatial learning.

Evaluation of anxiety in Parkinson's disease with some commonly used rating scales

This study assessed the concurrent validity of the State-Trait Anxiety Inventory (STAI), the Hospital Anxiety and Depression Scale (HADS) and the Hamilton Anxiety Scale (Ham-A) for evaluating anxiety in a group of 46 Parkinson's disease (PD) patients. The magnitude of correlations between the scales was high (all p<0.01), indicating a good concurrent validity. The item-by item analysis indicated that the main characteristics of anxiety in PD patients were 'inability to relax', 'restlessness or inability to feel calm' and 'feeling tense'. The association between anxiety, as measured by the HADS-A, with demographic characteristics or clinical features of PD was not significant, supporting existing data suggesting that anxiety in PD is not closely correlated with the severity of motor symptoms or the degree of disability. The HADS-A may be the most appropriate scale for documenting patient-reported anxiety in depression.

Changes in forearm reciprocal inhibition following pallidal stimulation for dystonia

The authors recorded forearm H reflex reciprocal inhibition and clinical outcome in eight patients with primary torsion dystonia before and 1, 3, and 6 months after pallidal deep brain stimulation (DBS). There was progressive increase in reciprocal inhibition after surgery, which correlated with clinical improvement. The authors conclude that pallidal DBS for dystonia results in functional reorganization of the nervous system, which includes a long-term increase in spinal inhibition.

Subtractive chromatography for purification and recovery of nano-bioproducts

A novel polymer-coated adsorbent (subtractive adsorbent) has been manufactured and evaluated for the recovery of nanoparticle bioproducts. The core principle was to coat inert macroporous polymers (e.g. agarose) upon adsorbent beads of varied ligands. Here BSA nanoparticles, with an average nanoparticle diameter 95 nm, were fabricated and selected as feedstock for the demonstration of the principle. The adsorption of a mixture of fluorescently labelled BSA solution and BSA nanoparticles was investigated in a batch binding experiment upon polymer-coated Streamline DEAE and visualised by laser scanning confocal microscopy. The mechanistic design of such adsorbents and their basic application for the recovery of target nano-bioproducts from complex feedstock is strongly indicated.

Preparation and purification of synthetic protein nanoparticulates

The protein nanostructure used in this study (bovine serum albumin; BSA nanoparticles) were fabricated with an average nanoparticle diameter 150 nm based on the principle of coacervation. Practical recovery of nanoparticulate mimics, of products such as plasmid DNA and viruses as putative gene therapy vectors from model systems, has been studied. The adsorbents employed in this study for the recovery of nanoparticles had one of four discrete designs i.e. microporous (pore size <0.2 microm), macroporous (pore size >0.8 microm), solid phase (nonporous) and pellicular (pore size <0.5 microm). Soluble protein was included in the study to represent cellular components of complex feedstocks and the separation of assemblies from components, while particulate protein served as surrogate size and charge mimics of less easily sourced viral and plasmid gene therapy vectors. Candidate adsorbents were physically characterised to assess their suitability for fluidised-bed operation, biochemically characterised exploiting batch-binding experimentation and laser scanning confocal microscopy. The adsorptive capacity of nanoparticulate products was strongly influenced by the physical design of the adsorbents, and microporous adsorbents appeared to be less suited for the recovery of nanoparticulate products. The generic application of such adsorbents for the recovery of nanoparticulate bioproducts is discussed.