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Biomedical subjects

K R Rao

Publications and source records attributed to K R Rao.

At least 73 records · Page 4Linked to original sources
PubMed1985

Combined action of carbaryl and phenthoate on a freshwater fish (Channa punctatus bloch).

The toxic potencies of carbaryl and phenthoate were studied on a freshwater fish, Channa punctatus, by evaluating the percentage kill at different concentrations of exposure. To determine the combined action of these compounds, LC studies were performed by using carbaryl (C) and phenthoate (P) mixtures in the 1:3, 1:1, and 3:1 ratios. The 48-hr LC50 values obtained by calculating the data with probit method were 8.71 ppm for carbaryl and 0.473 ppm for phenthoate. Similar values on the mixtures were 0.717, 0.741, and 0.750 ppm for 1:3, 1:1, and 3:1, carbaryl:phenthoate mixtures. The toxicities of carbaryl and phenthoate have been discussed in relation to sensitivity of the species and their interaction with the target enzyme. Effectiveness of the joint action of carbaryl and phenthoate was determined by measuring three different parameters: the CTC value, the V value, and the CI value. This analysis showed that 3C:1P combination exerted marked synergism, 1C:1P exerted moderate synergism, and 1C:3P showed moderate antagonism.

Animals↗
PubMed1985

[Nle4, D-Phe7]-alpha-MSH: a superpotent melanotropin with prolonged action on vertebrate chromatophores.

The in vitro and in vivo responses of integumental chromatophores to alpha-MSH and a related analogue, [Nle4, D-Phe7] -alpha-MSH, were studied in a number of vertebrate species: the teleost, Lebistes reticulatus; the amphibians, Rana pipiens, R. catesbeiana, Xenopus laevis, Bufo alvarius, and B. cognatus; the lizard, Anolis carolinensis; the rattlesnake, Crotalus atrox. The alpha-melanotropin analogue was a superpotent agonist in the in vitro frog (R. pipiens, R. catesbeiana) and lizard (A. carolinensis) skin bioassays. In all species studied, the analogue exhibited ultraprolonged melanotropic activity, both in vitro and in vivo. This melanotropin and related analogues should prove useful in the study of numerous physiological processes, particularly when prolonged melanotropic activity is desired.

Animals↗
PubMed1985

Characterization of a pigment-dispersing hormone in eyestalks of the fiddler crab Uca pugilator.

A pigment-dispersing hormone (PDH) from eyestalks of the fiddler crab Uca pugilator has been purified by gel filtration, ion-exchange chromatography, partition chromatography, and reversed-phase liquid chromatography. Based on automated gas-phase sequencing and subsequent identification of carboxyl-terminal amide, we have assigned the primary structure of this peptide as Asn-Ser-Glu-Leu-Ile-Asn-Ser-Ile-Leu-Gly-Leu-Pro-Lys-Val-Met-Asn-Asp-Ala-NH (2). We have confirmed the sequence by synthesizing this peptide and demonstrating that the synthetic PDH and the native PDH display identical chromatographic behavior and biological activity. This hormone is a member of a family of invertebrate neuropeptides that includes a light-adapting/pigment-dispersing octadecapeptide hormone from the prawn Pandalus borealis. In assays for melanophore pigment dispersion in destalked fiddler crabs, Uca PDH was 21-fold more potent than Pandalus PDH. These two hormones share a hexapeptide core sequence (residues 5-10: -Ile-Asn-Ser-Ile-Leu-Gly-) as well as the amino- and carboxyl-terminal residues but differ at positions 3, 4, 11, 13, 16, and 17. These results point to speciesrelated or group-specific structural differences among crustacean PDHs.

Journal Article↗
PubMed1985

Effect of different pion stopping volumes on the radiation response of mouse small intestine.

This radiobiological investigation was based on measurements of crypt cell survival in mouse small intestine when the animals were exposed to 5 cm3 (spot), 350 cm3 and 3010 cm3 (the latter two were spot scans) pion stopping volumes generated by the multi-channel Piotron of the Swiss Institute for Nuclear Research. The experimental data obtained indicate that there was a decrease in biological effectiveness when the pion treatment volume was enlarged, irrespective of whether the pion dose was delivered in a single exposure or in four fractions. The r.b.e. values for pion beams relative to 200 kVp X-rays for the different experimental conditions used in this study are presented. The phenomenon of decreasing biological effectiveness with increasing pion stopping volume may be attributed to the following two factors: (1) when the pion stopping volume is increased there is a corresponding dilution of the high l.e.t. component of the beam; (2) the biological test system used may be sensitive to radiation dose rate which varied by a ratio of about 20 for the pion volumes used in this study.

Animals↗
PubMed1984

Effect of malathion on protein synthetic potentiality of the tissues of the teleost, Tilapia mossambica (Peters), as measured through incorporation of [14C]amino acids.

The protein turnover was studied in muscle, gill and liver tissues of the fish, Tilapia mossambica, under malathion impact through the incorporation of labelled amino acids using [14C]glutamic acid, [14C]leucine and [14C]arginine as representatives of acidic, neutral and basic types of proteins, respectively. The labelled amino acid incorporation indicated the synthetic potentiality of proteins to be elevated in all the tissues of malathion-exposed (ME) fish. The results are discussed in relation to the degradative and synthetic capability of tissue proteins under malathion exposure.

Amino Acids↗
PubMed1984

Mitotic and pigment-translocating activities of cultured chromatophores of the guppy, Lebistes reticulatus.

Using Ham's F-12 medium, an in vitro culture system permitting cellular survival for over 6 months has been developed for the chromatophores of the guppy. In this culture system, the various types of chromatophores (melanophores, erythrophores and xanthophores) migrated out of the explanted tail fin tissue, retained their pigmentation, and displayed both mitotic and pigment-translocating activities. The mitotic activity was evident during the first 3 or 4 weeks in culture, whereas the pigment-translocating ability persisted for 16 weeks. The cultured chromatophores of male fish displayed pigment aggregation in response to adrenergic agents (epinephrine and norepinephrine) and pigment dispersion in response to alpha-melanocyte stimulating hormone (alpha-MSH), cyclic AMP and dibutyryl cyclic AMP. Cyclic GMP did not elicit pigment-translocating responses in any of the chromatophores.

Animals↗
PubMed1984

Rutoside and the X-ray induced damage in jejunal mucosa of mouse.

The effect of O-(beta-hydroxyethyl)-Rutoside on the radiation response of mouse small intestine was investigated. The post-irradiation mitotic regeneration in jejunal crypts, the survival of crypt stem cells and the post-irradiation mortality of animals were taken as criteria. Multiple treatment with rutoside (300 mg/kg/injection) combined with a whole-body-X-irradiation failed to show protective effect in all the cases studied. Some possibilities which may explain these results are presented.

Animals↗
PubMed1984

Iron stores in adults with sickle cell anemia.

Iron status was investigated in 60 adults with sickle cell anemia as determined by stainable iron in bone marrow aspirates, serum ferritin, serum iron, and the total iron-binding capacity. Seventeen patients (28%) were found to have absent bone marrow iron. There was an excellent inverse correlation between serum ferritin and the serum transferrin (p less than 0.001), and a significant positive correlation between serum ferritin and transferrin saturation (p less than 0.005), bone marrow iron (p less than (p less than 0.001), and history of prior blood transfusion (p = 0.005). Results of complete radiologic examination of the gastrointestinal tract and proctoscopy were negative in the 17 patients in the iron-deficient group. The high incidence of iron deficiency may be related to excessive urinary losses of iron. Our data indicate that serum ferritin values of less than 30 ng/ml are diagnostic of iron deficiency in patients with sickle cell anemia, with a high degree of specificity (98.7%). However the sensitivity of the test at a serum ferritin level of 30 ng/ml is only 32%. The diagnostic evaluation and the management of sickle cell anemia in iron-deficient patients needs to be better defined.

Adolescent↗
PubMed1983

Response of mouse small intestine to fractionated doses of pions.

The effect of single or fractionated doses of stopping pions or 200 kV X-rays on the mouse jejunal crypt cells was used to determine in vivo RBE values. For single fraction, the pion/X-ray RBE was 1.27 and it increased to about 1.31 when two fractions were applied at 3 or 24 h interval. When four fractions were given at 3 h intervals, the RBE was 1.46. This is because the fraction of "dose repaired" was always higher for X-rays than for pions and this difference was enhanced when more dose fractions were used. The data presented is, in general, consistent with the biological effects of pions reported for other in vivo end points.

Animals↗
PubMed1983

Serum ferritin and sequestered stores of body iron.

A 47-year-old man with sickle cell anemia, chronic cor pulmonale, and congestive heart failure died following a short illness. A diagnosis of iron deficiency was established during life by usually accepted criteria including a low serum ferritin concentration. Autopsy showed no stainable iron in the bone marrow, liver, and the heart. Marked deposits of iron were seen in the kidneys and the atrophic spleen. These findings suggest that the serum ferritin concentration may not reflect the metabolically sequestered stores of iron in the spleen and the kidneys.

Anemia, Sickle Cell↗
PubMed1983

Radionuclide angiocardiographic analysis of myocardial function in myotonic muscular dystrophy.

Using radionuclide angiocardiography, we studied cardiac function in 10 men with myotonic muscular dystrophy who had no cardiac symptoms and were less than 50 years of age, comparing resting and exercise performance of the heart. Nine of 10 patients had an abnormality of myocardial function. The interaction of exercise-induced cardiomyopathy with conduction system abnormalities may be important in sudden cardiac dysfunction in patients with myotonic dystrophy.

Adult↗
PubMed1983

Infection with parvovirus-like virus and aplastic crisis in chronic hemolytic anemia.

From 1980 to 1982 seven adults with chronic hemolytic anemia were admitted to Cook County Hospital, Chicago, with aplastic crisis. Six of these patients had sickle cell anemia, the seventh patient had beta thalassemia intermedia. Virologic studies showed that six patients had acute infection with the human parvovirus-like virus; in the remaining patient the lack of appropriate specimens precluded viral diagnosis. We describe the features of the virus infection and accompanying erythroid aplasia, and discuss the role of parvovirus-like virus as the etiologic agent in the arrest of erythrocyte production.

Adolescent↗