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Biomedical subjects

M Rao

Publications and source records attributed to M Rao.

At least 235 records · Page 13Linked to original sources
PubMed1984

Renal cell carcinoma in a horseshoe kidney.

A case of renal cell carcinoma arising in a horseshoe kidney and presenting with a pathologic fracture of humerus is reported. Relevant literature is discussed.

Adenocarcinoma↗
PubMed1984

Production and Properties of Extracellular Endoxylanase from Neurospora crassa.

Neurospora crassa 870 produced 14 and 0.025 U of extracellular xylanase (1,4-beta-d-xylan xylanohydrolase; EC 3.2.1.8) and beta-xylosidase (1,4-beta-xylan xylohydrolase; EC 3.2.1.37) per ml, respectively, in 4 days when commercial xylan was used as a carbon source. The effects of pH and carbon sources on xylanase production by N. crassa are discussed. Two xylanases (I and II) were purified and had pI values of 4.8 and 4.5 and molecular weights of 33,000 and 30,000. The maximum degree of hydrolysis of xylan by the extracellular culture broth was 66% in 4 h. The end products of xylan hydrolysis by xylanase I and II showed the presence of xylose, xylobiose, xylotriose, xylotetraose, xylopentose, and arabinose, indicating that they are endoxylanases capable of hydrolyzing 1,3-alpha-l-arabinofuranosyl branch points. Both xylanases showed activity toward carboxymethyl cellulose but no activity toward para-nitrophenyl-beta-d-xyloside or laminarin. Xylanase I showed appreciable activity toward para-nitrophenyl-beta-d-glucoside, whereas xylanase II was inactive.

Journal Article↗
PubMed1984

Acute cervical lymphadenitis in hospitalized pediatric patients: predominance of Staphylococcus aureus in infancy.

Sixty-one cases of acute cervical lymphadenitis in Kings County Hospital Center were reviewed. Staphylococcus aureus accounted for 50 percent of the cases and Group A β-hemolytic streptococcus accounted for 15 percent; 35 percent had no growth on culture. Of the variables considered (age, sex, temperature, leukocytosis, previous antibiotic treatment, duration of symptoms, lymph node consistency) only age appeared to be a predictor of the causative organisms. Children under 1 year of age had a higher incidence of S aureus (65 percent) than children above 3 years of age (25 percent); the difference was statistically significant (P <.01). Therapeutic antimicrobial regimens should include coverage for S aureus in this age group.

Acute Disease↗
PubMed1983

Fusion resistance and decreased infectability as major host cell determinants of coronavirus persistence.

Mouse hepatitis virus persists in cultures of a subline (designated LM-K) of mouse LM cells but produces a lytic infection in L-2 cells. Persistence in the LM-K cells was not accompanied by production of ts mutants or of soluble anti-MHV factors. Infectious center assay demonstrated an approximately 500-fold lower level of infectibility by MHV of the LM-K cells as compared to L-2 cells. On an infected cell basis, production levels of infectious progeny and viral RNA were comparable between the two cell lines. The extent of virus-induced cell-cell fusion, however, was markedly reduced in the LM-K cells. Cell-mixing experiments showed that both infected L-2 and LM-K cells have the capacity of fusing with neighboring uninfected L-2 cells but not with uninfected LM-K cells. This suggests that the decreased level of fusion observed in the LM-K infection is due not to absence of viral fusion protein at the cell surface, but rather to an inherent resistance of the LM-K cell membrane to MHV-induced fusion. It is believed that such fusion resistance in LM-K cells moderates virus dissemination throughout the culture, thereby contributing to a state of virus persistence.

Animals↗
PubMed1983

A method for concentrating dilute solutions of macromolecules.

A simple, inexpensive acrylate polymer which has a capacity to absorb 170 ml of water per g has been developed. It can be used to concentrate dilute solutions of macromolecules such as proteins, nucleic acids, and carbohydrates. The polymer absorbs only low-molecular-weight substances such as glucose, sucrose, and inorganic salts. It can replace the various conventional concentration methods. No special device or electricity is needed for the concentration. The inexpensive polymer, molded in the form of rods, can be very conveniently used as "disposable concentration sticks."

Carbohydrates↗
PubMed1983

A continuing study of primary drug-resistant tuberculosis among children observed at the Kings County Hospital Medical Center between the years 1961 and 1980.

A 20-yr prospective study of the incidence of primary drug-resistant tuberculosis among children treated at the Kings County Medical Center was undertaken in January 1961 and extended through December 1980. There were 355 strains of Mycobacterium tuberculosis isolated during this time, 56 of which were found to be primarily resistant to one or more antituberculosis drugs, giving an overall resistance rate of 15.8%. The study was divided into five 4-yr periods. The resistance rate to isoniazid was 9.9%, varying from a peak of 15.2% in the third period of study (1969 to 1972) to 4.5% in the last period of study. The changes in the rate were not significant. The overall resistance rate for streptomycin was 9.2%. There were significant increases in the resistance rate in the second (1965 to 1968) and third (1969 to 1972) periods of study, but not in the last 2 periods. The rates for PAS (3.4%), rifampin (1%), and ethambutol (0.7%) were low. The type and severity of disease among those infected with a resistant strain were no different from those infected with a susceptible strain. Life-threatening disease was found in 10 of the 56 patients infected with a drug-resistant strain. There was one fatality in a child with meningitis who was treated early in the study. Our experience suggests that rifampin and ethambutol be included in the initial treatment regimen of all children with a life-threatening form of tuberculosis until the susceptibility pattern of the infecting strain is determined, after which the drug regimen can be modified if necessary.

Aminosalicylic Acid↗
PubMed1982

Synthesis of phosphatidylcholine under possible primitive earth conditions.

Using a primitive Earth evaporating pond model, the synthesis of phosphatidylcholine was accomplished when a reaction mixture of choline chloride and disodium phosphatidate, in the presence of cyanamide and traces of acid, was evaporated and heated at temperatures ranging from 25 degrees to 100 degrees C for 7 hours. Optimum yields of about 15% were obtained at 80 degrees C. Phosphatidylcholine was identified by chromatographic, chemical and enzymatic degradation methods. On enzymatic hydrolysis with phospholipase A2 and phospholipase C, lysophosphatidylcholine and phosphorylcholine were formed, respectively. Alkaline hydrolysis gave glycerophosphorylcholine. The synthesis of phosphatidylcholine as the major compound was accompanied by the formation of lysophosphatidylcholine in smaller amounts. Cyanamide was found to be essential for the formation of phosphatidylcholine, and only traces of HCl, of the order of that required to convert the disodium phosphatidate to free phosphatidic acid were found necessary for the synthesis. This work suggests that phosphatidylcholine, which is an essential component of most biological membranes, could have been synthesized on the primitive Earth.

Choline↗
PubMed1981

Potassium chloride versus voltage clamp contractures in ventricular muscle.

In frog ventricle, developed tension was markedly larger in response to depolarization caused by a voltage clamp step than to depolarization induced by high concentrations of potassium chloride. Measurement of extracellular potassium activity at the surface and at the depth of muscle during the development of contractures showed that the diffusion of potassium is much slower than the spread of depolarization through the cross section of muscle. These two observations suggest that competition between the depolarizing and the negative inotropic effects of an increase in the extracellular potassium ion concentration may determine the time course and magnitude of contractile tension in heart muscle.

Animals↗
PubMed1981

Persistent postpneumonic pneumatoceles in children.

Ten children who had developed pneumatoceles during the course of pneumonia are described. Seven of the ten patients had persistence of pneumatoceles for 12 months or more. There was no evidence of an underlying disorder in any of the patients, and all recovered completely without complications. The etiologic agent was identified in two of the ten cases as Staphylococcus aureus. In our experience, a delay in the resolution of pneumatoceles for a period of one or more years after an episode of pneumonia is not an unusual occurrence in normal healthy children.

Ampicillin↗
PubMed1980

Persistently negative tuberculin reactions: their presence among children with culture positive for Mycobacterium tuberculosis (tuberculin-negative tuberculosis).

Mantoux tests were performed on 200 children with culture-proven Mycobacterium tuberculosis infections. A group of 28 patients initially had negative reactions to 5 TU PPD-S. Of these, 17 had had extensive or overwhelming tuberculous disease at the time of admission, seven of whom reacted to 250 TU PPD; after a course of chemotherapy, all the survivors had positive reactions to 5 TU PPD-S. The 11 with less severe disease had negative reactions to 5 TU PPD-S and 250 TU PPD, as well as to PPD-A/B/G; in only two could a ready explanation be found for the negative reactor state. In general, a small number of children without life-threatening forms of tuberculosis may have persistently negative tuberculin reactions without any apparent cause. In such cases, other criteria for diagnosis must be relied on, such as lymphocyte transformation, culture, and biopsy.

Adolescent↗
PubMed1980

Clays in prebiological chemistry.

In this review an attempt is made to highlight the structures and properties of clay that may contribute to a better understanding of the role of clays in chemical evolution. The adsorption of organic molecules on clays has been demonstrated, as has the synthesis of bioorganic monomers in the presence of clays. For instance, amino acids (glycine, aspartic acid, threonine, alanine and others) as well as purines and pyrimidines, have been obtained from CO and NH3 in the presence of clays at relatively high temperatures (250-325 degrees C). Carbohydrates are also easily derived from formaldehyde at relatively low temperatures (approximately equal to 80 degrees C). The oligomerization of biochemical monomers, mediated by clays has also been shown to result in the formation of polymer molecules basic to life. For instance the condensation of amino acyl adenylates at room temperature in the presence of montmorillonite is known to yield polypeptides in discrete ranges of molecular weights with degrees of polymerization up to 56. Clays have also been found to affect the condensation of mononucleotides to oligonucleotides. Although the role of clays in the origin or metabolic pathways has not been demonstrated, it is possible that clays may have played a cooperative role with catalytic peptides in an intermediate stage of prebiological chemistry preceding the emergence of life on this planet.

Adsorption↗