Prakash S. Nagarkatti

Use of sensitized spleen cells in capillary tube migration inhibition test to demonstrate cellular sensitization to dengue virus in mouse

Abstract When immune spleen cells packed into glass capillaries were allowed to migrate in the presence of medium containing dengue virus antigen, there was a specific inhibition of the migration of these cells in vitro. This inhibition appears to be due to the production of MIF as the culture supernatant obtained by incubating sensitized spleen cells and dengue antigen was found to contain this factor. When T and B cells were purified from immune spleen cells and lymph nodes, it was observed that only T cells produced MIF thereby suggesting that spleen cell migration inhibition is a specific T-cell mediated immune phenomenon and that dengue virus elicits cell-mediated immunity. The feasibility of using the direct spleen cell migration inhibition test as an in vitro assay to detect CMI in mice is being discussed.

Suppression of intrinsic B-cell function in Dengue-infected mice

Mice infected with Dengue virus show a depressed immune response to lipopolysaccharide (LPS), a helper T-cell-independent antigen, when LPS was administered on day 0, 6 and 12 post infection. Mice injected with inactivated virus failed to show immunosuppression.

Short-term toxicity studies of O-chlorobenzylidene malononitrile on humoral immunity in mice

The effect of O-chlorobenzylidene malononitrile (CS) on the immune system was studied in mice given 8 and 16 mg/kg body weight i.p. of the compound, daily for 10 days. The humoral immune response to SRBC was suppressed at both doses, as determined by the antibody producing cells in the spleen. To find out whether the immunosuppression observed was due to the indirect effect of CS on the nutritional status and endocrine balance, serum proteins and corticosterone levels were measured. While the serum proteins did not alter, corticosterone levels rose significantly only in mice receiving higher dose of CS.

Development of a kit for the assay of haemagglutination inhibition antibodies to flaviviruses using formalinized goose erythrocytes

Haemagglutination inhibition (HI) test using goose erythrocytes (GRBC) is the method of choice for screening antibodies to various arboviruses. This test makes use of fresh GRBC preserved in dextrose-gelatin-veronal (DGV). We have tried formalinizing GRBC and have found that such cells can retain the surface property of being agglutinated by arboviruses and, therefore, can be used in haemagglutination (HA) and HI tests. Unlike fresh cells preserved in DGV, formalinized cells can be preserved for a long time without haemolysis or loss of sensitivity. They can also be frozen or lyophilized. Making use of these properties, a kit has been developed for the assay of HI antibodies to some members of the flavivirus group. Use of this kit simplifies the HI test and enables it to be carried out routinely by any hospital or laboratory to screen arboviral infections.

Effect of experimental dengue virus infection on humoral and cell-mediated immune response to thymus-dependent antigen.

Mice injected with dengue virus showed a depressed primary and secondary humoral immune response to SRBC as measured by the number of antibody-forming cells, haemagglutinin and haemolysin titres. The time of administration of SRBC during the infection was found to be an important factor determining the response to SRBC. The cell-mediated immune response was also suppressed as measured by the delayed hypersensitivity reaction to SRBC in the footpad. While the immunosuppression of humoral immunity was only transient and the animals recovered within 30 days following infection, the cell-mediated immunity remained suppressed throughout this period. Immunofluorescent studies and LD50 determination of the infected brains demonstrated significant virus titres from 7 to 15 days postinfection. This period coincided with maximal immunosuppression.

Immunotherapy for Glioblastoma

The most common and deadliest brain tumor is glioblastoma, which escapes immune recognition and kills the patients with a year of diagnosis. Glioblastomas, like other malignancies, are highly capable of overcoming host immune defenses through a variety of mechanisms some of which are quite clear. Currently, there is a growing interest in developing immunotherapeutics for treatment of glioblastomas; however, very little is known about glioblastoma-specific immune responses. A better understanding of the molecular interactions between the tumor and the host immune system may allow the development of novel integrated approaches based on the simultaneous control of tumor escape pathways and the activation of anti-tumor immune responses. An appropriate combination therapy that may induce long-lasting immune responses against glioblastoma should be attempted. The primary goal of immunotherapy for glioblastoma should be to overcome tolerance and to re-educate the immune system, when the tumor burden is reduced following surgery, radiotherapy and chemotherapy. This article describes the latest developments in the glioblastoma immunology and immunotherapy.

Dietary indoles serve as novel therapeutic agents by targeting inflammation through epigenetic modulation and miRNA expression in T cells and there by suppressing inflammatory diseases

The power laws are ubiquitous but we have to find them . Recently, power laws are extensively studied almost in every field -Science, Engineering, Economics Finance and Management. For the past three years, we have been working on applications of Power Laws to Pharmaceutical phenomena. We found power laws operating in pharmaceutical literature (Pharmacists’oaths of USA and India), in most of the editorials of reputed Indian English news papers (Times of India, Hindu, Deccan Chronicle, Economic Times etc.,); Pharmaceutics (frequency and ranks of oil globules in emulsions, Powder Technology (Sieve analysis), Epidemiology (prevalence of H1N1 in USA and global (2010); Pharmaco-Epidemiology-ADEs with regard to certain selected drugs. Existing estimations of drug dosing are based on body weight-kg/mg. As the drug clearance rate is dependent upon metabolic rate, there is a pressing need to bring in metabolic rate into equation while titrating doses of drugs. We have compared and contrasted three methods of dosing of drugs: Dosing by body weight (kg/mg)–Linear dosage Scale, Dosing by ¾ Power Law (Kleiber’s Law), and Dosing by 2/3 Power Law (Rubner’s Law). From the data available in public domain, ADEs were extracted for Tami flu, Avandia, Celebrex, Bextra, Paxil, and Relenza. Using least-square method, hypothetical ADEs were estimated in each case, when Kleiber’s Law / Rubner’s Law were inserted into the equations of dosings.I a poorly soluble and highly permeable non-steroidal anti-inflammatory drug, used to reduce pain, swelling involved in osteoarthritis, rheumatoid arthritis and ankylosing spondylitis. Indomethacin shows low and erratic oral bioavailability due to poor solubility. The main purpose of this work was to develop self emulsifying drug delivery system (SEDDS) to enhance oral bioavailability of indomethacin. SEDDS is mixture of oils, surfactants, and co-surfactants, which are emulsified in aqueous media under conditions of gentle agitation and digestive motility that would be encountered in the gastro-intestinal (GI) tract. Solubility of indomethacin was determined in various vehicles. Pseudoternary phase diagrams were constructed to identify the efficient self-emulsifying region. Based on solubility and Isotropicity studies and emulsifying ability labrafil, cremophor EL and transcutol P were selected as oil, surfactant and co surfactant respectively. The developed SEDDS were evaluated for its percentage transmittance, assay, phase separation study, droplet size analysis, zeta potential, turbidity, viscosity and in vitro release studies. In vitro release studies were carried by using USP dissolution apparatus XXIV-Type II. Antiinflammatory studies were conducted in Wistar strain male albino rats by using optimized formulation, drug suspension and marketed product. Optimized formulation showed significant anti-inflammatory activity than the drug suspension and marketed product. Our studies illustrated that the developed SEDDS is potential alternative for the immediate delivery of hydrophobic compounds such as indomethacin by oral route.Clinical Research is a branch of medical science that experiments new drug, medical device or biological on human subjects prior to approval. For the study to be credible, unbiased and generally applicable, all ICH-GCP regulations, other international and local regulations governing ethical clinical research studies should strictly be adhered to. The current regulations for clinical research are based on a combination of ethical thoughts and history. Ethics is different from law and regulation, both of which mandate a certain way of acting. The United States regulations for the protection of human subjects and other regulatory agencies from different countries have provided minimum baseline with which everyone must comply in operating an institutional review board (IRB), obtaining informed consent from research subjects and conducting research in an ethical manner. The challenge, especially in a practical environment such as clinical research, is to translate these regulatory documents, provisions and different ethical principles into action. In clinical research, the consent of the research participants should be received before they are enrolled for trial. Many years after the document governing ethical principles of clinical research was developed and addressing three major areas: respect for persons, beneficence and justice, abuse of informed consent process has been a major ethical problem in most clinical research conducted across the globe and especially those conducted in Africa. Is informed consent process well administered? Do these patients have a good comprehension of the entire research process? Is informed consent a mere signing of a paper to participate in a trial, or a continuous process?. Is there a better way of administering informed consent to achieve a better research outcome that will benefit all? This review shall focus on recalling history of abuses of informed consent process and ways to correct the unethical practice shall be discussed.