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Biomedical subjects

M Rao

Publications and source records attributed to M Rao.

286 records · Page 16Linked to original sources
PubMedDate not supplied

Murine IgG subclass antibodies to antigens incorporated in liposomes containing lipid A.

The IgG subclass responses to antigens incorporated in liposomes containing lipid A were investigated using a synthetic malarial antigen (SPf66) and cholera toxin (CT). The antigen-specific IgG subclass response was determined in BALB/c mice immunized with either: (a) SPf66 encapsulated in liposomes containing lipid A, (b) CT bound to the surface of liposomes containing lipid A, or (c) both encapsulated SPf66 and surface-bound CT in the same liposomes. In each case the antibodies to SPf66, CT and lipid A demonstrated an IgG2a predominance. Liposomes containing lipid A not only increased the magnitude of the antibody response to liposomal antigens but elicited predominantly IgG2a subclass antibodies as well.

Animals↗
PubMedDate not supplied

On the preparation, characterization, and enzymatic activity of fungal protease-gold colloid bioconjugates.

We present herein details pertaining to the preparation of bioconjugates of colloidal gold with aspartic protease from the fungus Aspergillus saitoi (F-prot) and their characterization and enzymatic activity. Simple mixing of the colloidal gold and protein solutions under protein-friendly conditions (pH = 3) followed by centrifugation (to remove uncomplexed gold nanoparticles and protein molecules) results in the formation of the fungal protease-gold nanoparticle conjugates. The protein-gold nanoparticle bioconjugate was redispersed in buffer solution and indicated the formation of efficient bioconjugates with intact native protein structures. The bioconjugates in solution were characterized by UV-vis spectroscopy, fluorescence spectroscopy, and biocatalytic activity measurements while drop-dried bioconjugate films on Si (111) substrates were characterized by scanning electron microscopy (SEM), energy dispersive analysis of X-rays (EDAX), and X-ray diffraction (XRD) measurements. Microscopy images do show some aggregate formation, but the intactness of the native structure of the enzyme in the bioconjugate material was verified by fluorescence and biocatalytic activity measurements. The enzyme retains substantial biocatalytic activity in the bioconjugate material and was comparable to that of free enzyme in solution.

Aspartic Acid Endopeptidases↗
PubMedDate not supplied

The transmission of donor-derived malignant melanoma to a renal allograft recipient.

The transmission to organ transplant recipients of donor origin malignancy in the allograft has been described. Here we report the transmission of malignant melanoma in a renal allograft transplanted from a multiorgan donor. The lung transplant recipient presented with an allograft lesion that was proven to be melanoma and of donor-origin based on human leukocyte antigen (HLA)-DR typing. One renal allograft recipient was undergoing his second deceased donor renal transplant, having lost his first graft from recurrent IgA nephropathy. He was unsensitized and immunosuppression consisted of tacrolimus, mycophenolate and prednisolone. He achieved stable graft function and there were no episodes of rejection. Four and a half months post-transplant a diagnosis of donor origin melanoma in the lung recipient was made and his immunosuppression was stopped. He presented with clinical rejection two wk later and a transplant nephrectomy was undertaken. Histology demonstrated vascular and cellular rejection and there was a 3-mm melanoma deposit with no evidence of tumour infiltrating lymphocytes. Three years post-transplant he remained clinically well with no evidence of melanoma and received his third deceased donor renal transplant. This was complicated by cellular rejection in the first week treated with methylprednisolone and vascular rejection at day 10 treated with anti-thymocyte globulin. Three months post-transplant he has achieved good allograft function and remains well with no evidence clinically or on imaging of metastatic melanoma. The other renal allograft recipient was receiving his first deceased donor transplant, having end-stage renal failure of uncertain aetiology. His immunosuppression was not stopped until melanoma was proven in the renal allograft pair six months post-transplant and he then presented with clinical rejection six wk later. Transplant nephrectomy was undertaken and histology did not demonstrate melanoma, but severe vascular and cellular rejection was evident. At three-yr post-transplant he remains disease free clinically and on imaging. At present, the cardiac allograft recipient has no evidence of transmitted melanoma. The highest risk of transmission of donor origin melanoma appears to be from donors who are older and have died from an intracerebral haemorrhage. It is likely these donors have metastatic melanoma and their intracerebral haemorrhage is not primary but has occurred in an unrecognized metastatic cerebral deposit. While the occurrence of donor-transmitted malignancy is not common, the outcome is often fatal.

Graft Rejection↗
PubMedDate not supplied

IL-4 production by T depleted cells from Nippostrongylus brasiliensis infected mice.

Interleukin-4 (IL-4) is known to be involved in both the in vivo IgE response and the elevated B cell IgE Fc receptor (Fc epsilon R11) expression seen after a parasite infection. To further analyze the relationship between Fc epsilon R11 expression and IL-4 production, purified B cells from uninfected, Nippostrongylus brasiliensis (Nbr) infected and from goat anti-mouse IgD (GaM delta) injected mice were isolated on various days post-treatment. The Fc episolon R11 levels on purified B cells from normal mice decreased after an overnight culture in media alone and addition of IL-4 to these cultures resulted in a 4 to 13-fold enhancement of Fc epsilon R11 levels. In contrast, the Fc epsilon R11 levels on B cells from Nbr infected mice were elevated after an overnight culture in media alone and addition of IL-4 did not further enhance the already upregulated Fc epsilon R11 levels. Overnight culture of purified B cell blasts from Nbr infected mice in the presence of an anti-IL-4 monoclonal antibody (11B11) caused the elevated Fc epsilon R11 levels to return to levels seen in normal mice, without affecting the Fc epsilon R11 levels on purified Go or B cell blasts from uninfected mice or Go B cells from Nbr infected mice. 11B11 also inhibited the elevated Fc epsilon R11 levels on highly purified B cells obtained by FACS sorting the non-adherent spleen cell population for class II+ cells. In contrast to Nbr infection, the Fc epsilon R11 levels on B cells were downregulated in the GaM delta injected mice. However, analogous to the Nbr system, the Fc epsilon R11 levels were unresponsive to the addition of exogenous IL-4. This study indicates that IL-4 production is seen in T depleted splenocytes and that this alternate source of IL-4 serves to maintain the elevated Fc epsilon R11 levels on B cells.

Animals↗
PubMedDate not supplied

Immunosuppression in live-related donor renal transplantation.

BACKGROUND: Triple immunosuppression with cyclosporine, azathioprine and prednisolone is the most common regimen employed following renal transplantation. No information is available regarding its impact on the results of renal transplantation in India. The present study is an audit of a fixed-dose cyclosporine-based immunosuppressive regimen in an exclusively live-related donor transplant programme, with specific regard to graft and patient outcomes. METHODS: Patients transplanted over a 3-year period and receiving cyclosporine-based immunosuppression were studied. The relationship between immunosuppression and graft outcomes [rejection episodes (RE), graft function, graft survival], and patient outcomes (patient survival) was analysed in those receiving triple immunosuppression. Dosage schedules were audited. Cyclosporine trough level monitoring was employed at graft dysfunction episodes, or at dose reduction points. RESULTS: The median follow up was 14 months. Triple drug immunosuppression was used in 191 patients and double drug therapy in 26. The overall one-year patient survival rate was 91% and the corresponding graft survival rate was 90%. An audit of dosing schedules showed that over the first 6 months post-transplant, cumulatively, 20%-50% of patients received azathioprine, and 55%-60% received cyclosporine in doses below the protocol. The immunosuppressive doses (both of cyclosporine and azathioprine) in the first month were significantly related to the RE (p < 0.01) in the first month and the total number of RE in the first 6 months (p < 0.01). The other predictors were younger recipient age and older donor age. The sixth-month serum creatinine level was predicted by the donor age, the level of serum creatinine in the first month and the total number of RE in the first 6 months post-transplant. While no specific predictors of graft loss were identified in this cohort, diabetic nephropathy (p = 0.000) as the native renal disease, and the total number of RE were strongly related to patient mortality. The occurrence of > or = 2 RE in the first 6 months was an independent predictor, increasing the risk of death in the first 2 years post-transplant by 2.3 (p = 0.0001, 95% CI: 1.5-3.4). CONCLUSIONS: Sub-therapeutic baseline immunosuppression in the early post-transplant period predisposes to acute RE. This has an impact not only on graft function but also forms an important proximate marker of mortality, as seen in this cohort. Thus, immunosuppressive drug dosage should be optimized and therapeutic drug level monitoring strategies should be preemptive rather than event related, especially in the early post-transplant period. While fixed-dose immunosuppressive drug schedules are widely followed, it is possible to fall short of the target unless a specific effort is made to meet and sustain schedules.

Adolescent↗
PubMedDate not supplied

Effects of vitamin/mineral supplementation on the proliferation of esophageal squamous epithelium in Linxian, China.

Abnormalities of epithelial proliferation have been proposed as an early step in gastrointestinal carcinogenesis. To determine whether micronutrient supplementation may reduce squamous epithelial proliferation in the esophagus, we evaluated proliferation in subjects participating in a randomized nutrition intervention trial in Linxian, China, where esophageal cancer rates are among the highest in the world. After 30 months of intervention involving daily supplementation with multiple vitamins and minerals, an endoscopic survey was performed and squamous biopsies from 512 subjects were labeled with tritiated thymidine and autoradiographed. Analysis showed no treatment effect on the overall amount of squamous epithelial proliferation measured by the total labeling index. However, a measure of the vertical distribution of labeled cells showed lower values with supplementation: a 14% reduction in all subjects (P = 0.29), and a 29% reduction in nonsmokers (P = 0.03). These results suggest a potential modest benefit for short-term intervention with multiple vitamins and minerals on squamous epithelial cell proliferation of the esophagus in this high-risk population.

Adult↗
PubMedDate not supplied

Direct calorimetry for the measurement of heat release in preterm infants: methods and applications.

Direct calorimetry is a sensitive and accurate method for the measurement of biologic heat release in humans. At the Children's Medical Center of Brooklyn, State University of New York, we have established direct calorimetry for the measurement of heat release by low birth weight premature infants. We have tested the method and find it to be simple, safe, and accurate. We studied heat release in 10 low birth weight infants on 22 occasions. The smallest infant in the study group weighed 1.43 kg. All the infant underwent direct calorimetry between 1 week and 18 weeks of age. Heat release in the infants ranged from 1.31 kcal/kg/hr. This method of direct calorimetry offers a tool for measuring total metabolic heat release from the first weeks of life in very low birth weight infants to estimate the insensible water losses and to examine the effect of various feeding regimens and disease states on total heat release.

Body Temperature Regulation↗
PubMedDate not supplied

Oral lesions in relation to prosthetics. A review.

The oral mucosa is not designed to provide a foundation for denture base and is called upon to function in a new environment. Although dentures are fabricated for the purpose of improving health and well being of the patient, they may occasionally become injurious to oral tissues. Dentures are worn because of their essential role in appearance, in speech and mastication far outweighs their potential for damage. A thorough knowledge of the histologic features of the structures that support dentures is necessary for proper denture service. Various pathologic lesions that can occur following use of dentures are reviewed in this article.

Burning Mouth Syndrome↗