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Biomedical subjects

M Rao

Publications and source records attributed to M Rao.

At least 109 records · Page 6Linked to original sources
PubMed1997

Reduced heat loss following sucrose ingestion in premature and normal human newborns.

To determine the energy savings caused by sucrose taste, we measured heat loss through direct calorimetry for 23 premature and normal term infants who were studied a total of 31 times. Following stabilization in the calorimeter, crying was induced by applying 1 ml cold water to the infant's foot. After 4 min, 0.1 or 0.2 ml sucrose were delivered intraorally through a remote syringe to arrest crying. Crying was accompanied by a 13.2% increase in metabolic rate that was quickly and completely reversed during crying cessation caused by sucrose taste. Heat loss was inversely and linearly related to infant body weight. The implications of these findings for minimizing crying and energy expenditure in normal newborns and especially in ill or small newborns are discussed.

Basal Metabolism↗
PubMed1997

RPTP delta and the novel protein tyrosine phosphatase RPTP psi are expressed in restricted regions of the developing central nervous system.

Transmembrane receptor-type protein tyrosine phosphatases (RPTPs) form a novel and potentially important class of cell regulatory proteins. To identify RPTPs expressed during neural development we have characterized RPTPs transcribed in embryonic day (E)13.5 rat neural tube. Nine different phosphatases, one of which was novel, were identified. We examined the expression of the novel phosphatase, called RPTP psi, and of two other phosphatases, RPTP delta and RPTP mu, whose expression in the developing nervous system has not yet been described in detail. The expression of RPTP mu in small blood capillaries in developing neural tissue is consistent with an involvement in angiogenesis. In contrast, the temporally and spatially regulated expression of RPTP psi and RPTP delta in neuroepithelium suggests a role in early neural development. In the spinal cord, early expression of RPTP delta in the roof plate is followed by its expression in differentiating motor neurons. RPTP psi mRNA is also transiently detectable in the roof plate as well as in floor plate cells. In the telencephalon as well as in the hindbrain at E13.5, the reciprocal expression patterns of RPTP delta and RPTP psi are consistent with a sequential function, RPTP psi exerting its activity in undifferentiated progenitor cells and RPTP delta functioning during neuronal differentiation.

Amino Acid Sequence↗
PubMed1997

Visualization of peptides derived from liposome-encapsulated proteins in the trans-Golgi area of macrophages.

Exogenous proteins are generally not presented through the major histocompatibility complex (MHC) class I pathway, yet several recent studies show that particle-associated antigens induce a CD8+ T-cell response. Therefore, a pathway must exist in vivo for the presentation of exogenous antigens on class I molecules. In the present study, we investigated the intracellular fate of liposome-encapsulated Texas Red (TR)-conjugated protein in cultured bone marrow-derived macrophages (BMs). After phagocytosis of liposomes, the fluorescent liposomal protein, initially associated with the liposomal lipids in phagosomes, later entered the cytoplasm, and the processed protein was subsequently visualized in the trans-Golgi as a fluorescent peptide. Experiments performed with BMs from transporter associated with antigen processing (TAP1) knock-out mice demonstrated that the translocation of peptides into the trans-Golgi area was dependent upon TAP1 protein. We conclude that delivery of liposomal proteins or peptides to the cytoplasm of phagocytes and subsequent transport of peptides to the Golgi via the classical MHC class I pathway involving TAP proteins might explain the known propensity of liposomal antigens to induce cytotoxic T-lymphocytes (CTLs).

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1997

A comparative study of army and civilian babies in a UK garrison town.

Army families in the UK have been observed to have a higher infant mortality compared with the civilian population. Little is known about the reasons for the higher mortality. We report a comparative study of the health of army and civilian babies and their families in a UK garrison town, the aim being to investigate any differences in risk factors which may have explained the differences in mortality. A total of 250 first born army and civilian babies fulfilling the selection criteria were recruited to the study. Army babies had a lower birth weight distribution and both maternal and paternal smoking rates were higher in army families. In addition, social support and in particular, contact with close family members appeared to be available to fewer army mothers. The study highlighted the needs of this population and prompted a number of local health services to work together to address the issues it raised.

Adult↗
PubMed1997

Weighted least-squares reconstruction methods for positron emission tomography.

We present unpenalized and penalized weighted least-squares (WLS) reconstruction methods for positron emission tomography (PET), where the weights are based on the covariance of a model error and depend on the unknown parameters. The penalty function for the latter method is chosen so that certain a priori information is incorporated. The algorithms used to minimize the WLS objective functions guarantee nonnegative estimates and, experimentally, they converged faster than the maximum likelihood expectation-maximization (ML-EM) algorithm and produced images that had significantly better resolution and contrast. Although simulations suggest that the proposed algorithms are globally convergent, a proof of convergence has not yet been found. Nevertheless, we are able to show that the unpenalized method produces estimates that decrease the objective function monotonically with increasing iterations.

Algorithms↗
PubMed1997

Ultra sonographic measurements of the normal liver and spleen among Egyptians 10-50 years old.

OBJECTIVE: To determine reference values of ultra sonographic (US) measurements of the normal liver, spleen, portal vein, right and left periportal thickness, gall bladder wall thickness and common bile duct diameter of Egyptians. DESIGN: Community-based cross sectional study. SETTING: Kalama village in Nile Delta, 40 kilometers north of Cairo. SUBJECTS: 10% systematic sample of people above 10 years of age. Selection criteria included normal clinical examination, normal liver functions by ALT, absence of hepatitis B and C virus markers and liver or spleen pathology by US. MEASUREMENTS: Organometery of the liver, spleen, portal vein, right and left periportal thickness, gall bladder wall thickness and common bile duct diameter by US. RESULTS: 217 subjects were admitted to the study out of 700 examined. All measured parameters increased with age till 20 years. There was no significant difference in measurements between males and females. The means, standard deviation and 95th percentiles of all measurements were higher than those recorded in other studies. CONCLUSION: Egyptian norms for US organometery of the liver, spleen, portal vein and gall bladder are different from those of other countries. We suggest that Egyptian sonologists use these norms in routine practice.

Adolescent↗
PubMed1997

Investigations of anti-inflammatory activity of Jigrine.

Jigrine, a polypharmaceutical herbal formulation containing 14 medicinal plants is used in the Unani system of medicine for the treatment of liver ailments. The antiinflammatory activity of Jigrine (0.5 ml and 1.0 ml/kg, po), was evaluated against acute inflammation caused by carrageenin (injecting 0.1 ml of 1% carrageenin in 0.9% NaCl solution into plantar surface of the hind paw of the rat) and the effect of Jigrine (1 ml/kg/day, po for 7 days) was also studied on the sub-acute inflammation induced by cotton pellet granuloma. The paw volume, biochemical parameters like tissue AST, ALT, gamma-GTP and lipid peroxides and dry wt. of granuloma were measured to assess the anti-inflammatory activity. It showed a significant anti-inflammatory activity as evidenced by lowering the elevated levels of paw volume and biochemical parameters. But it could not reduce the sub-acute inflammation caused by cotton pellet granuloma. The study suggests that Jigrine has significant effect only on acute phase of inflammation caused by carrageenin. Antioxidant and membrane stabilizing action of Jigrine might be responsible for its anti-inflammatory effect.

Alanine Transaminase↗
PubMed1997

Cell lineage determination and the control of neuronal identity in the neural crest.

The molecular mechanisms underlying the determination of neuronal identity in the vertebrate peripheral nervous system are only just beginning to come into focus. Many of these mechanisms, such as the involvement of cascades of bHLH transcription factors and lateral inhibition via the Notch-Delta system, appear to have been conserved from Drosophila (Ghysen et al. 1993; Jan and Jan 1993). The way in which these genetic circuits are controlled by instructive growth factors, and the manner in which they lead to expression of a particular neuronal identity, is far from clear. This process is being elucidated by studies of neurogenesis in the peripheral autonomic lineage, which is arguably the best-understood neurogenic lineage in vertebrates. Emerging evidence is beginning to suggest that neuronal diversity within the autonomic and sensory lineages may be generated by related, but distinct, mechanisms. All autonomic progenitors express a common bHLH protein, MASH1, which appears to be induced by members of the BMP2 subfamily secreted by the tissues to which these progenitors migrate. Additional signals may then act on these progenitors in different locations to induce the expression of other transcription factors, which act in conjunction with MASH1 to specify the final phenotypes of the different autonomic neuron subtypes (sympathetic, parasympathetic, and enteric). Although different classes of autonomic neurons develop in very different locations within the body, different classes of sensory neurons are located together in dorsal root ganglia. The finding that distinct but related subtypes of bHLH proteins, the neurogenins, are expressed by different classes of sensory neuron precursors early in development suggests that sensory neuron diversity, in contrast to autonomic neuron diversity, may be pre-specified at or before the time neural crest cells begin their emigration from the neural tube.

Animals↗
PubMed1996

Genetic transfer of thermophilic trait from alkalophilic thermophilic Bacillus to E.coli.

The genomic library of alkalophilic thermophilic Bacillus was constructed in E.coli. A single recombinant [pATB 507 I] out of 10,000 colonies showed growth at 50 degrees C, which produced large, opaque and mucilaginous colonies on LB. The IMViC biochemical tests suggested that the strain was E.coli, and scanning electron microscopy revealed increased cell length. The plasmid DNA from the thermophilic recombinant showed multiple bands. The cured strain showed ampicillin resistance (10 micrograms/ml) and presence of insert DNA in the genome, as revealed by southern blot analysis. The thermophilic trait was transformable with 10(-4) frequency of expression amongst the pATB 507I transformants. The hybridization of E.coli genomic DNA with labeled genomic DNA from alkalophilic thermophilic Bacillus suggested that the genetic recombination(s) of the insert DNA was an essential prerequisite for expression of thermophilic trait. The conjugative plasmid (RP4) mediated mobilization of thermophilic trait resulted in thermophilic conjugants after 2 h incubation. Southern blot analysis revealed that a single locus [5.6 kb Bam HI fragment] was involved in the transfer of thermophilic trait.

Bacillus↗
PubMed1996

Structural environment of an essential cysteine residue of xylanase from Chainia sp. (NCL 82.5.1).

N-(2,4-Dinitroanilino)maleimide (DAM) reacts covalently with the thiol group of the xylanase from Chainia leading to complete inactivation in a manner similar to N-ethylmaleimide, but provides a reporter group at the active site of the enzyme. Increasing amounts of xylan offered enhanced protection against inactivation of the xylanase by DAM. Xylan (5 mg) showed complete protection, providing evidence for the presence of cysteine at the substrate-binding site of the enzyme. Kinetics of chemical modification of the xylanase by DAM indicated the involvement of 1 mol of cysteine residue per mol of enzyme, as reported earlier [Deshpande, Hinge and Rao (1990) Biochim. Biophys. Acta 1041, 172-177]. The second-order rate constant for the reaction of DAM with the enzyme was 3.61 x 10(3) M-1.min-1. The purified xylanase was alkylated with DAM and digested with pepsin. The peptides were separated by gel filtration. The specific modified cysteinyl peptide was further purified by reverse-phase HPLC. The active-site peptide was located visually by its predominant yellow colour and characterized by a higher A340 to A210 ratio. The modified active-site peptide has the sequence: Glu-Thr-Phe-Xaa-Asp. The sequence of the peptide was distinctly different from that of cysteinyl peptide derived from a xylanase from a thermotolerant Streptomyces species, but showed the presence of a conserved aspartic acid residue consistent with the catalytic regions of other glucanases.

Actinomycetales↗
PubMed1996

Evaluating new vaccines for developing countries. Efficacy or effectiveness?

Despite the profusion of promising new vaccines against illnesses prevalent in developing countries, uncertainties about the balance between costs and benefits of new vaccines have retarded their use in public health practice. Conventional prelicensure trials of vaccine protection exacerbate these uncertainties by focusing on measurement of vaccine efficacy--the performance of a vaccine under idealized conditions. Vaccine effectiveness trials provide a more pragmatic perspective by addressing the performance of a vaccine under the ordinary conditions of a public health program, by capturing direct as well as indirect effects of vaccination, and by comprehensively addressing outcomes of public health concern. The use of effectiveness trials should enable more rational triaging of new vaccines for developing countries and may accelerate the introduction of new vaccines into public health practice by resolving speculative debates about practical costs and benefits.

Case-Control Studies↗
PubMed1996

A serine alkaline protease from the fungus Conidiobolus coronatus with a distinctly different structure than the serine protease subtilisin Carlsberg.

In view of the functional similarities between subtilisin Carlsberg and the alkaline protease from Conidiobolus coronatus, the biochemical and structural properties of the two enzymes were compared. In spite of their similar biochemical properties, e.g., pH optima, heat stability, molecular mass, pI, esterase activity, and inhibition by diisopropyl fluorophosphate and phenylmethlysulfonylfluoride, the proteases were structurally dissimilar as revealed by (1) their amino acid compositions, (2) their inhibition by subtilisin inhibitor, (3) their immunological response to specific anti-Conidiobolus protease antibody, and (4) their tryptic peptide maps. Our results demonstrate that although they are functionally analogous, the Conidiobolus protease is structurally distinct from subtilisin Carlsberg. The Conidiobolus protease was also different from other bacterial and animal proteases (e.g. pronase, protease K, trypsin, and chymotrypsin) as evidenced by their lack of response to anti-Conidiobolus protease antibody in double diffusion and in neutralization assays. The Conidiobolus serine protease fails to obey the general rule that proteins with similar functions have similar primary sequences and, thus, are evolutionarily related. Our results strengthen the concept of convergent evolution for serine proteases and provide basis for research in evolutionary relationships among fungal, bacterial, and animal proteases.

Amino Acids↗
PubMed1996

Molecular docking programs successfully predict the binding of a beta-lactamase inhibitory protein to TEM-1 beta-lactamase.

Crystallization of the 1:1 molecular complex between the beta-lactamase TEM-1 and the beta-lactamase inhibitory protein BLIP has provided an opportunity to put a stringent test on current protein-docking algorithms. Prior to the successful determination of the structure of the complex, nine laboratory groups were given the refined atomic coordinates of each of the native molecules. Other than the fact that BLIP is an effective inhibitor of a number of beta-lactamase enzymes (KI for TEM-1 approximately 100 pM) no other biochemical or structural data were available to assist the practitioners in their molecular docking. In addition, it was not known whether the molecules underwent conformational changes upon association or whether the inhibition was competitive or non-competitive. All six of the groups that accepted the challenge correctly predicted the general mode of association of BLIP and TEM-1.

Amino Acid Sequence↗
PubMed1996

Clinical manifestation and outcome of tuberculosis in children with acquired immunodeficiency syndrome.

BACKGROUND: Atypical clinical manifestations and rapid progression of tuberculous disease (TB) are well-recognized in adults with the acquired immunodeficiency syndrome (AIDS). There are few reports of children with AIDS and TB. We report the manifestations, clinical course and outcome of 12 pediatric patients with AIDS and TB. METHODS: The charts of all children admitted to our institution, from 1989 through 1994, with the diagnoses of AIDS and culture-proved TB were reviewed. RESULTS: Twelve children between the ages of 2 months and 13 years fit the criteria. The mean time between the diagnosis of AIDS and TB was 20 months. The most frequent presenting symptoms were fever (75%) and tachypnea (33%). All had negative Mantoux tests (5 tuberculin units of purified protein derivative). Extrapulmonary TB was present in 3 (25%). A source case was identified for 4 (33%). Previous pulmonary disease was present in 7 (58%). Chest roentgenograms were abnormal in 11 (91%), with diffuse interstitial infiltration the most common finding. Susceptibility tests were performed on 10 strains, 3 of which were resistant to 1 or more antituberculosis drugs. Three patients (25%) died of TB, 1 of whom was appropriately treated with antituberculosis drugs but had a strain resistant to isoniazid and rifampin. CONCLUSION: Children with AIDS and TB most frequently present with atypical manifestations of TB. A high index of suspicion is needed to correctly diagnose TB in this group of children. Early diagnosis is important because most respond well when treated appropriately.

AIDS-Related Opportunistic Infections↗