Phytochemical screening, antimicrobial activity, in vitro and in vivo antioxidant activity of Berberis lycium Royle root bark extract

Abstract Antioxidants are materials that scavenge or remove free radicals from living systems. The oxidation process ends in the production of free radicals. These free radicals are the chief birthplace of cancerous cells. Antioxidizing agents remove free radical intermediates by terminating oxidation processes by being oxidized themselves. On the other hand, infectious diseases affect the world on a large scale. To fight these diseases several synthetic compounds have been used. Plant based medications play important role in this regard. So, the current research aimed to investigate the antibacterial and antioxidant effect of Berberis lycium Royle root bark (BLR) extract. Berberis lycium Royle was used for phytochemical analysis and also as antimicrobial and antioxidant agents. The antimicrobial activity was evaluated by the agar well diffusion method. Current study revealed that BLR was rich in phytochemicals and toxic against tested pathogenic bacteria. BLR showed the highest activity against S. pyogenes (13.3±0.8 mm). The lowest antibacterial activity was reported against E. coli (0±0 mm). In case of minimum inhibitory concentration, it was observed that BLR with 10 μg/mL concentration showed the highest activity while 2.5 μg/mL of BLR showed the least inhibitory activity. The highest In vitro antioxidant activity was recorded as 65% at 100 µg/mL. In case of in vivo antioxidant activity level of CAT, GSH and SOD were decreased while that of MDA was enhanced in groups treated with CCl4 as compared to the control group. BLR extract treatment reversed all these changes significantly. Current results indicate that BLR is effective against bacterial pathogens and also has antioxidant potential.

New Triazinoindole Bearing Benzimidazole/Benzoxazole Hybrids Analogs as Potent Inhibitors of Urease: Synthesis, In Vitro Analysis and Molecular Docking Studies

Twenty-four analogs based on triazinoindole bearing benzimidazole/benzoxazole moieties (1-25) were synthesized. Utilizing a variety of spectroscopic methods, including ¹H-, ¹³C-NMR, and HREI-MS, the newly afforded compounds (1-25) were analyzed. The synthesized analogs were tested against urease enzyme (in vitro) as compared to the standard thiourea drug. All triazinoindole-based benzimidazole/benzoxazole analogs (1-25) exhibited moderate to excellent inhibition profiles, having IC₅₀ values of 0.20 ± 0.01 to 36.20 ± 0.70 μM when evaluated under the positive control of thiourea as a standard drug. To better understand the structure-activity relationship, the synthesized compounds were split into two groups, "A" and "B." Among category "A" analogs, analogs 8 (bearing tri-hydroxy substitutions at the 2,4,6-position of aryl ring C) and 5 (bearing di-hydroxy substitutions at the 3,4-position of aryl ring C) emerged as the most potent inhibitors of urease enzyme and displayed many times more potency than a standard thiourea drug. Besides that, analog 22 (which holds di-hydroxy substitutions at the 2,3-position of the aryl ring) and analog 23 (bearing ortho-fluoro substitution) showed ten-fold-enhanced inhibitory potential compared to standard thiourea among category "B" analogs. Molecular docking studies on the active analogs of each category were performed; the results obtained revealed that the presence of hydroxy and fluoro-substitutions on different positions of aryl ring C play a pivotal role in binding interactions with the active site of the targeted urease enzyme.

Study of resveratrol against bone loss by using in-silico and in-vitro methods

By applying the in-silico method, resveratrol was docked on those proteins which are responsible for bone loss. The Molecular docking data between the resveratrol and Receptor activator of nuclear factor-kappa-Β ligand [RANKL] receptors proved that resveratrol binds tightly to the receptors, showed the highest binding affinities of -6.9, -7.6, -7.1, -6.9, -6.7, and -7.1 kcal/mol. According to in-vitro data, Resveratrol reduced the osteoclasts after treating Marrow-Derived Macrophages [BMM] with Macrophage colony-stimulating factor [MCSF] 20ng / ml and RANKL 50ng / ml, with different concentrations of resveratrol (2.5, 10 μg / ml) For 7 days, the cells were treated with MCSF (20 ng / ml) and RANKL (40 ng / ml) together with concentrated trimethyl ether and resveratrol (2.5, 10 μg / ml) within 12 hours. Which, not affect cell survival. After fixing osteoclast cells with formaldehyde fixative on glass coverslip followed by incubation with 0.1% Triton X-100 in PBS for 5 min and after that stain with rhodamine phalloidin staining for actin and Hoechst for nuclei. Fluorescence microscopy was performed to see the distribution of filaments actin [F.actin]. Finally, resveratrol reduced the actin ring formation. Resveratrol is the best bioactive compound for drug preparation against bone loss.

Evaluation of antibacterial activity of vitamin C against human bacterial pathogens

Now a day's multidrug resistance phenomenon has become the main cause for concern and there has been an inadequate achievement in the development of novel antibiotics to treat the bacterial infections. Therefore, there is an unmet need to search for novel adjuvant. Vitamin C is one such promising adjuvant. The present study was aimed to elucidate the antibacterial effect of vitamin C at various temperatures (4°C, 37°C and 50°C) and pH (3, 8, and 11), against Gram-positive and Gram-negative bacteria at various concentrations (5-20 mg/ml) through agar well diffusion method. Growth inhibition of all bacterial strains by vitamin C was concentration-dependent. Vitamin C significantly inhibited the growth of Gram-positive bacteria: Bacillus licheniformis (25.3 ± 0.9 mm), Staphylococcus aureus (22.0 ± 0.6 mm), Bacillus subtilis (19.3 ± 0.3 mm) and Gram-negative bacteria: Proteus mirabilis (27.67 ± 0.882 mm), Klebsiella pneumoniae (21.33±0.9 mm), Pseudomonas aeruginosa (18.0 ± 1.5 mm) and Escherichia coli (18.3 ± 0.3 mm). The stability of vitamin C was observed at various pH values and various temperatures. Vitamin C showed significant antibacterial activity at acidic pH against all bacterial strains. Vitamin C remained the stable at different temperatures. It was concluded that vitamin C is an effective and safe antibacterial agent that can be used in the future as an adjunct treatment option to combat infections in humans.

Extraction of chitin from edible crab shells of Callinectes sapidus and comparison with market purchased chitin

Chitin and its derived products have immense economic value due to their vital role in various biological activities as well as biomedical and industrial application. Insects, microorganism and crustaceans are the main supply of chitin but the crustaceans shell like shrimp, krill, lobsters and crabs are the main commercial sources. Chitin content of an individual varies depending on the structures possessing the polymer and the species. In this study edible crabs' shells (Callinectes sapidus) were demineralized and deproteinized resulting in 13.8% (dry weight) chitin recovery from chitin wastes. FTIR and XRD analyses of the experimental crude as well as purified chitins revealed that both were much comparable to the commercially purchased controls. The acid pretreatment ceded 54g of colloidal chitin that resulted in 1080% of the crude chitin. The colloidal chitin was exploited for isolation of eighty five chitinolytic bacterial isolates from different sources. Zone of clearance was displayed by the thirty five isolates (41.17%) succeeding their growth at pH 7 on colloidal chitin agar medium. Maximum chitinolytic activity i.e. 301.55 U/ml was exhibited by isolate JF70 when cultivated in extracted chitin containing both carbon and nitrogen. The study showed wastes of blue crabs can be utilized for extraction of chitin and isolation of chitinolytic bacteria that can be used to degrade chitin waste, resolve environmental pollution as well as industrial purpose.

AB1121 IMPLEMENTING HIGH VALUE CARE IN INPATIENT ANTINUCLEAR ANTIBODY TESTING

Background:

Antinuclear Antibody (ANA) testing forms the basis on which many rheumatological diseases are subsequently diagnosed. ANA testing quantifies the dilution of plasma to produce the titer and staining pattern and this can be a part of an ANA order set that reflexively cascades to sub-serology if positive. Studies have shown that a low titer ANA may potentially translate into an erroneous diagnosis: if one estimates a 1 percent prevalence of ANA associated disease in the general population then 30% of those individuals would have a false positive result of ANA detected at 1:40 titer [1]. We theorized that there is no need for several methods to coexist within a single inpatient hospital setting especially since diagnostic value of staining patterns alone is limited.

Objectives:

To compare the utility and yield of “ANA screening reflex to profile” (ARP) and “ANA reflex to titer” (ART) order sets in the inpatient setting of a community tertiary care hospital. We aim to identify the appropriateness of the ANA testing ordered including cost-effectiveness of ordering ARP over ART in order to implement the identified quality measures towards improving utilization of ANA testing.

Methods:

We identified all inpatient ANA reflex testing orders performed at Community Regional Medical Center, Fresno, California completed between 11/2018 till 07/2019. This included ART and ARP orders with 6 sub-serologies: SSA, SSB, dsDNA, Smith, Scl-70 and U1RNP. A Health Information Management report was generated which included patient’s age, gender, length of hospital stay, dates of testing ordered, principal diagnosis and type of ANA testing ordered. Descriptive statistics were computed and analyzed.

Results:

We reviewed a total of 1,012 ANA lab orders performed between 11/01/2018 until 07/30/2019 performed on 700 patients. According to the laboratory standard using Immunofluorescence Assay, an ANA titer starting from 1:40 is reported as positive. Out of the 1,012 tests, 334 tests were positive i.e. 33%. The ART order by itself contributed to 29.9% of the positive testing while ARP formed 70% of the positive testing. 56 of the 910 ARP (6%) performed had one or more sub-serology antibody positive while in 178 ARP orders (20%) only the ANA titer was positive with negative serology. The most common sub-serology antibody noted positive was dsDNA forming 54% of the positive serology results. Multiple testing was noted with 218 orders of ARP and ART being ordered on the same patient within the same week, which shows 21.5% of ANA lab orders were repetitive. Length of stay was noted to be more than 3 days for 89% of the patients who had repetitive testing, majority of those tests (99%) on the same day by the same medical provider. It cost $5.0 for an ART order that resulted negative and $5.0 for an ARP panel that resulted negative. It cost $10.0 for those patients who had both ART and ARP ordered with negative results. A positive ART result added $12.0 additional to the cost of each positive ANA profile ($67.36) when both tests were ordered together.

Conclusion:

Our study findings reflect the need for using higher yield ANA testing that has been standardized. It demonstrated that physicians ordering the testing were not familiar with the ART vs. ARP, and the laboratory orders needed to be re-structured. We removed the ART from the inpatient Electronic Medical Record i.e. Epic system so that only the ARP order remained. This would prevent repetitive testing and reduce healthcare costs through reduction by at least $12.0 per positive ANA result and may also translate into reduced length of hospital stay. We were able to add Centromere Antibody (Ab) to the ANA profile sub serologies to standardize it further as it is an important part of Scleroderma diagnosis.

References:

[1]Range of antinuclear antibodies in “healthy” individuals. AU, Tan EM, et al. Arthritis Rheum. 1997; 40(9):1601

Disclosure of Interests:

None declared

ANCA-associated vasculitis causing nasopalatal destruction

Autoimmune disorders and their manifestations can be very problematic to diagnose and manage. The symptoms can be ambiguous and debilitating. Early intervention is necessary to counter the unforgiving consequences of delayed intervention, such as loss of sight or hearing and destruction of affected tissues. Vasculitis in the head and neck region is rare. A case of ANCA-associated vasculitis causing extensive destruction is presented to enhance our understanding of this devastating multisystem disorder.

Surgical review of the anatomical variations of the internal jugular vein: an update for head and neck surgeons

BACKGROUND

The internal jugular vein is one of the major vessels of the neck. The anatomy of this vessel is considered to be relatively stable. It is an important landmark for head and neck surgeons as well as the anaesthetists for both diagnostic and therapeutic purposes.

METHODS

We present two case reports of the posterior tributary of the internal jugular vein and review the surgical literature regarding anatomical variations of the vein.

FINDINGS

A total of 1197 patients from 27 published papers were included in this review. Of these patients, 99.6% had neck surgery and the rest were cadaveric dissections. Anatomical variations of the internal jugular vein were found in 2% of the patient cohort (n = 40). The majority of these patients had either bifurcation or fenestration of the vein. The posterior tributary of the internal jugular vein is unusual and is scarcely reported in the literature (three cases). Knowledge of variations in the anatomy of the internal jugular vein assists surgeons in avoiding complications during neck surgery and preventing morbidity. Two rare cases of posterior branching of the internal jugular vein and experience of other surgeons are demonstrated in this extensive review.

Sclerosing polycystic adenosis of the oral cavity

Minor salivary glands are ubiquitous in the oral cavity, and related diseases are often indolent and asymptomatic. We describe the unusual features of sclerosing polycystic adenosis, and its similarities to more sinister conditions of the minor salivary glands. Its importance is currently uncertain and research points to a pathogenesis that is neoplastic, which can create ambiguity. Sclerosing polycystic adenosis is a newly-discovered condition that merits further discussion and research to evaluate its full impact.

The relationship between different information sources and disease-related patient knowledge and anxiety in patients with inflammatory bowel disease

BACKGROUND

Patient education forms a cornerstone of management of inflammatory bowel disease (IBD). The Internet has opened new avenues for information gathering.

AIM

To determine the relationship between different information sources and patient knowledge and anxiety in patients with IBD.

METHODS

The use of information sources in patients with IBD was examined via questionnaire. Anxiety was assessed with the hospital anxiety and depression scale and disease-related patient knowledge with the Crohn's and colitis knowledge score questionnaires. Associations between these outcomes and demographics, disease-related factors, and use of different information sources were analysed using linear regression analysis.

RESULTS

Of 307 patients (165 Crohn's disease, 142 ulcerative colitis) 60.6% were female. Participants used the hospital IBD team (82.3%), official leaflets (59.5%), and official websites (53.5%) most frequently in contrast to alternative health websites (9%). University education (P < 0.001), use of immunosuppressants (P = 0.025), Crohn's and Colitis UK membership (P = 0.001), frequent use of the hospital IBD team (P = 0.032), and frequent use of official information websites (P = 0.005) were associated with higher disease-related patient knowledge. Female sex (P = 0.004), clinically active disease (P < 0.001), frequent use of general practitioners (P = 0.014), alternative health websites (homoeopathy, nutritionists, etc.) (P = 0.004) and random links (P = 0.016) were independently associated with higher anxiety.

CONCLUSIONS

Different patient information sources are associated with better knowledge or worse anxiety levels. Face-to-face education and written information materials remain the first line of patient education. Patients should be guided towards official information websites and warned about the association between the use of alternative health websites or random links and anxiety.

Prevalence of, and predictors of, bile acid malabsorption in outpatients with chronic diarrhea

BACKGROUND

Many physicians do not consider the diagnosis of bile acid malabsorption in patients with chronic diarrhea, or do not have access to testing. We examined yield of 23-seleno-25-homo-tauro-cholic acid (SeHCAT) scanning in chronic diarrhea patients, and attempted to identify predictors of a positive test.

METHODS

Consecutive patients with chronic diarrhea undergoing SeHCAT scan over a 7-year period were identified retrospectively. Bile acid malabsorption was defined as present at a retention of <15%. Medical records were reviewed to obtain information regarding proposed risk factors. Gastrointestinal symptoms were recorded, and patients were classified as having diarrhea-predominant irritable bowel syndrome (IBS-D) if they reported abdominal pain or discomfort. Independent risk factors were assessed using multivariate logistic regression, and odds ratios (ORs) with 99% confidence intervals (CIs) were calculated.

KEY RESULTS

Of 373 patients, 190 (50.9%) had bile acid malabsorption. Previous cholecystectomy (OR 2.51; 99% CI 1.10-5.77), terminal ileal resection or right hemicolectomy for Crohn's disease (OR 12.4; 99% CI 2.42-63.8), and terminal ileal resection or right hemicolectomy for other reasons (OR 7.94; 99% CI 1.02-61.6) were associated with its presence. Seventy-seven patients had IBS-D, and 21 (27.3%) tested positive. There were 168 patients with no risk factors for a positive SeHCAT scan, other than chronic diarrhea, and 63 (37.5%) had bile acid malabsorption.

CONCLUSIONS & INFERENCES

Bile acid malabsorption was present in 50% of patients undergoing SeHCAT scanning. Almost 40% of those without risk factors had evidence of bile acid malabsorption, and in those meeting criteria for IBS-D prevalence was almost 30%.

The mechanism of agonist induced Ca2+ signalling in intact endothelial cells studied confocally in in situ arteries

In endothelial cells there remain uncertainties in the details of how Ca²⁺ signals are generated and maintained, especially in intact preparations. In particular the role of the sarco-endoplasmic reticulum Ca²⁺-ATPase (SERCA), in contributing to the components of agonist-induced signals is unclear.

The aim of this work was to increase understanding of the detailed mechanism of Ca²⁺ signalling in endothelial cells using real time confocal imaging of Fluo-4 loaded intact rat tail arteries in response to muscarinic stimulation. In particular we have focused on the role of SERCA, and its interplay with capacitative Ca²⁺ entry (CCE) and ER Ca²⁺ release and uptake. We have determined its contribution to the Ca²⁺ signal and how it varies with different physiological stimuli, including single and repeated carbachol applications and brief and prolonged exposures.

In agreement with previous work, carbachol stimulated a rise in intracellular Ca²⁺ in the endothelial cells, consisting of a rapid initial phase, then a plateau upon which oscillations of Ca²⁺ were superimposed, followed by a decline to basal Ca²⁺ levels upon carbachol removal. Our data support the following conclusions: (i) the size (amplitude and duration) of the Ca²⁺ spike and early oscillations are limited by SERCA activity, thus both are increased if SERCA is inhibited. (ii) SERCA activity is such that brief applications of carbachol do not trigger CCE, presumably because the fall in luminal Ca²⁺ is not sufficient to trigger it. However, longer applications sufficient to deplete the ER or even partial SERCA inhibition stimulate CCE. (iii) Ca²⁺ entry occurs via STIM-mediated CCE and SERCA contributes to the cessation of CCE. In conclusion our data show how SERCA function is crucial to shaping endothelial cell Ca signals and its dynamic interplay with both CCE and ER Ca releases.

Postanaesthetic shivering--a new look at tramadol

We studied whether tramadol administered at the time of wound closure can prevent postanaesthetic shivering. One hundred and fifty patients scheduled for general anaesthesia and surgery were randomly allocated and tramadol was administered intravenously at a dose of 2 mg.kg(-1) in the high-dose group, 1 mg.kg- in the low-dose group and 0.9% saline in the control group. In the high-dose group, 2% of patients had postanaesthetic shivering, compared to 4% in the low-dose group and 48% in the control group (p < 0.001 vs. tramadol groups). There was no delay in tracheal extubation after reversal of neuromuscular blockade. The incidence of adverse side-effects such as sedation and vomiting did not differ statistically and were clinically not significant. This study strongly supports the use of tramadol at wound closure for prevention of postanaesthetic shivering.

Diabetic foot ulcer--a prospective study

OBJECTIVE

To detect "Feet at Risk" early, its early diagnosis and treatment of foot ulceration to prevent amputation.

SETTING AND METHOD

One hundred patients with diabetic foot problems were seen at Baqai Institute of Diabetology and Endocrinology from 06-01-97 to 14-04-99. Each Patient was examined for peripheral pulses, sensations and reflexes, for dryness of skin, deformity, callus and nail disorders and were photographed on first visit.

RESULTS

There were 65% males and 35% females included in this study. Ninety nine patients were type II diabetics, 38% were either smokers or had other addictions (or were addicted to tobacco). Awareness about risk factors causing foot problems was lacking among all patients. Fifty percent patients were on oral hypoglycaemic agents, 48% were insulin treated, while 2% were on diet and exercise alone. Glycaemic control was poor in 70%, fair in 16% and was good in 14%, 31% were overweight and 5% patients were underweight. Duration of diabetes was greater than ten years in 58%, toes were affected in 44%, sole/metatarsal in 18%; rest included malleoli, heel etc. Eleven patients had ulcers on both feet. Neuropathic ulcer were 42%, neuro ischaemic 58%, Sixty nine percent patients were in the age group between 40-60 years. Cause unknown 29% blisters and boil 14%, trauma/cutting 17%, burns 8%, dry skin/callus 10%. Fundal changes were present in 37%; proteinuria in 37%, ischaemic heart disease in 20%, hypertension 18%, In 60% more than one antibiotic was used. Foot ulcers of fifty nine patients healed on conservative management, six patients had below knee amputation, fifteen had toe amputation; nine were still on treatment, eleven lost contact.

CONCLUSION

Lack of awareness, poor glycaemic control and duration of diabetes were the main factors causing diabetic foot problems. This study also confirmed that microvascular complications should be screened in patients with diabetic foot ulcers. Foot care education would be the most important way of dealing with this major problem.

Pyuria as predictor of bacteriuria in catheterized patients

Six hundred and nine urine samples were analyzed for pyuria to assess its efficacy as a predictor of bacteriuria, in catheterized patients, using different techniques of pus cells estimation. In 235 and 323 urine samples, pus cells were counted per high power field in centrifuged and uncentrifuged urine respectively, while in 51 urine samples pus cells were counted per cubic millimeter in uncentrifuged urine. All the urine samples were simultaneously cultured. Pyuria (pus cells > 10/HPF or CMM) was correlated with bacteriuria (colony count > 10(5) per ml). The overall efficacy of pyuria as a predictor of bacteriuria was low (52.01-60.78%) and there was no significant difference among the different techniques. It was concluded that pyuria as predictor of bacteriuria is the least reliable technique to be recommended in routine clinical practice.

Enhanced intracellular stability and efficacy of PEG modified dextranase in the treatment of a model storage disorder

A model for storage disorders was produced in the livers of mice by the administration of liposomally encapsulated FITC-dextran. Liposomally delivered dextranase was found to be more efficient in degrading the accumulated substrate as compared to the free enzyme. Dextranase was covalently modified with PEG, and liposomes were used as carriers for delivering the free and the modified enzyme to the liver at similar rates. The PEG-dextranase conjugate showed greater intracellular stability as compared to the native enzyme. Liposomally delivered PEG-dextranase, by virtue of its enhanced intracellular stability, could not only degrade the accumulated FITC-dextran, but could also prevent its further accumulation over a period of time. This enhanced intracellular stability of enzymes would be of importance in extending the catalytic life of therapeutically active enzymes and thereby improve their therapeutic potential for the treatment of intracellular storage disorders.

Enhanced stability and therapeutic utility of proteins upon conjugation with hydrophilic polymers

The Pharmacological utility of various exogenous proteins is considerably impeded, since upon infusion, they are liable to rapid systemic clearance, proteolysis, in addition to eliciting severe immunological reactions. Upon conjugation with hydrophilic polymers like polyethylene glycol and dextran, the altered topology of proteins, often hinders interaction with their corresponding complementary surfaces. This is manifest in their increased circulatory-lives, as a fall out of decreased binding to proteases, pre-existing antibodies and other opsonins that mediate clearance by the reticuloendothelial-system as well as receptors mediating specific organ uptake. Further, an increase in conjugate size beyond the threshold limit of 70 kDa, permits small proteins to escape clearance via renal filtration. Upon covalent modification, proteins are generally endowed with an intrinsic inertness which is reflected in their enhanced stability in extremes of pH and temperature, presence of proteases and other denaturing conditions. The enhanced intracellular stability of conjugates which may also be responsible for their altered immunological properties is likely to be a consequence of the changed physiochemical properties of the conjugates. The therapeutic efficacy of these conjugates in clinical trials indicate their tremendous utility in pharmacological procedures.

Enhanced intracellular stability of dextran-horse radish peroxidase conjugate: an approach to enzyme replacement therapy

Horse radish peroxidase (HRP), a mannose-containing glycoprotein was covalently modified by conjugation with dextran. The rapid uptake of HRP by the liver is markedly inhibited by mannan. The uptake of dextran-HRP conjugate by the liver, though lower compared to that of the free enzyme, is also partially inhibited by mannan. Liposomes were therefore used as carriers for delivering the free and the modified HRP to the liver. The dextran-HRP conjugate showed greater stability intracellularly as compared to the free enzyme. The enhanced stability of enzymes upon their extensive glycosylation with nondegradable sugar polymers would be of importance in extending the catalytic life of therapeutically active enzymes and thereby improve their therapeutic potential for the treatment of certain enzyme deficiency disorders.

Design of liposomes for circumventing the reticuloendothelial cells

Two different aspects of liposomal drug delivery to non-RES cells have been described. In one of the systems, by incorporating neutral glycolipids, with terminal beta-galactoside residue into liposomes, it is possible to target liposomes to the liver parenchymal cells, partially bypassing the RES. Asialoganglioside seems to be the most suited for this purpose. In another approach, various factors that prolong the lifespan of circulating liposomes have been discussed. It is possible to design such liposomes by imparting hydrophilicity to the liposomal surface. The effectiveness of a number of possible candidates, such as dextran, GM1 ganglioside and PEG, has been discussed in this context.

Conjugation of proteins and enzymes with hydrophilic polymers and their applications

The efficacy of a number of therapeutically active proteins and peptides is severely limited due to their instability in circulation. Of the various approaches used to stabilise these proteins, the one more successful is covalent modification of the protein or enzyme with some hydrophilic polymers such as dextran or PEG. These conjugates are more stable than the native protein both in vitro as well as in vivo. They exhibit enhanced resistant to proteolytic degradation, have a long-life in circulation and exhibit reduced immunogenicity. The therapeutic efficacy of these conjugates is also greatly enhanced compared to the native protein or enzyme.