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Biomedical subjects

A Singh

Publications and source records attributed to A Singh.

At least 739 records · Page 41Linked to original sources
PubMed1984

Chemotherapy of bovine tropical theileriosis: Theileria annulata infection.

Seven groups of calves were treated with parvaquone (993C: Clexon, Wellcome) (20 mg kg-1 intramuscularly) or halofuginone lactate (1.2 mg kg-1 orally) on the first, third or sixth day of significant pyrexia following artificial infection with the Hissar strain of Theileria annulata. Eight untreated control animals developed severe theileriosis and five died. All animals treated with parvaquone or halofuginone lactate on the first or third day of fever underwent relatively mild theileriosis and all of them recovered. One of five animals treated with parvaquone and three of six treated with halofuginone on the sixth day of fever died of theileriosis.

Administration, Oral↗
PubMed1983

Saccharomyces cerevisiae contains two discrete genes coding for the alpha-factor pheromone.

Two genes, MF alpha 1 and MF alpha 2, coding for the alpha-factor in yeast Saccharomyces cerevisiae were identified by in situ colony hybridization of synthetic probes to a yeast genomic library. The probes were designed on the basis of the known amino acid sequence of the tridecapeptide alpha-pheromone. The nucleotide sequence revealed that the two genes, though similar in their overall structure, differ from each other in several striking ways. MF alpha 1 gene contains 4 copies of the coding sequence for the alpha-factor, which are separated by 24 nucleotides encoding the octapeptide Lys-Arg-Glu-Ala-Glu(or Asp)-Ala-Glu-Ala. The first alpha-factor coding block is preceded by a sequence for the hexapeptide Lys-Arg-Glu-Ala and 83 additional amino acids. MF alpha 2 gene contains coding sequences for two copies of the alpha-factor that differ from each other and from alpha-factor encoded by MF alpha 1 gene by a Gln leads to Asn and a Lys leads to Arg substitution. The first copy of the alpha-factor is preceded by a sequence coding for 87 amino acids which ends with Lys-Arg-Glu-Ala-Val-Ala-Asp-Ala. The coding blocks of the two copies of the pheromone are separated by the sequence for Lys-Arg-Glu-Ala-Asn-Ala-Asp-Ala. Thus, the alpha-factor can be derived from 2 different precursor proteins of 165 and 120 amino acids containing, respectively, 4 and 2 copies of the pheromone.

Amino Acid Sequence↗
PubMed1983

Expression of the human interferon-gamma cDNA in yeast.

Several plasmids which direct the expression of human interferon-gamma (IFN-gamma) cDNA in the yeast Saccharomyces cerevisiae under the transcriptional control of the 3-phosphoglycerate kinase (PGK) promoter have been constructed. Up to 25 x 10(6) units per liter culture of biologically active IFN-gamma are synthesized in yeast transformed with these expression plasmids. The amount of IFN-gamma mRNA in yeast transformed with the IFN-gamma expression plasmids is much lower than the amount of PGK mRNA present when the PGK gene and promoter are inserted on a similar plasmid. The major and three minor sites of transcription initiation have been localized. The major starting point of the IFN-gamma mRNA is at 4 basepairs upstream of the PGK mRNA start. All transcription starts map at an ApG as does PGK mRNA. The yeast IFN-gamma mRNA terminates in a specific segment of the 3' untranslated region of the IFN-gamma cDNA. The polyadenylation site at about 182-184 nucleotides 3' of the IFN-gamma stop codon is preceded by a sequence which is very similar to a sequence proposed to be involved in transcription termination and polyadenylation (49).

Cloning, Molecular↗
PubMed1983

Energy production and utilization in contractile failure due to intracellular calcium overload.

Intracellular calcium overload was produced by perfusing the Ca2+- deprived rat hearts for 5 or 10 min with normal medium containing 1.25 mM Ca2+ for 10 min and changes in the myofibrillar and membrane ATPase, sarcolemmal adenylate cyclase, mitochondrial oxidative phosphorylation and high energy phosphate stores in failing hearts were examined. Myocardial creatine phosphate and ATP were decreased by the intracellular calcium overload whereas the myofibrillar, mitochondrial and microsomal ATPase activities were not altered. The intracellular calcium overload markedly depressed the mitochondrial oxidative phosphorylation as well as sarcolemmal Ca2+ ATPase, Mg2+ ATPase, Na+ - K+ ATPase and adenylate cyclase. These results suggest that abnormalities in the process of energy production rather than energy utilization may primarily account for the depressed energy state of hearts failing due to an intracellular calcium overload.

Adenosine Diphosphate↗
PubMed1983

Interactions of conventional or photopolymerized liposomes with platelets in vitro.

We have examined the effects of liposomes on in vitro platelet aggregation. Liposomes were prepared from various conventional lipids and from a novel photopolymerizable phosphatidylcholine derivative (DPL, bis[1,2-(methacryloyloxy)dodecanoyl]-L-alpha-phosphatidylcholine). None of the liposome preparations studied caused marked platelet aggregation in either plasma or buffer solution. However, positively charged vesicles impaired the ability of platelets in plasma to aggregate in response to ADP, whereas negatively charged vesicles impaired the ability of platelets in buffer to aggregate in response to thrombin. DPL vesicles had only modest effects on platelets in plasma or buffer.

Adenosine Diphosphate↗
PubMed1983

Effect of gamma radiation on E. coli ribosomes, II. Efficiencies of inactivation by free radicals.

Efficiencies for the inactivation of ribosomes by the hydrogen atom, the hydrated electron, the hydroxyl radical and radicals derived from isopropanol and tertiary-butanol, have been calculated. The relative inactivation efficiencies of the hydrogen atom, the hydrated electron and the hydroxyl radical are 4.2, 0.8 and 1, respectively. The oxygen enhancement ratio for damage by the hydroxyl radical is 2.5.

1-Propanol↗
PubMed1983

Thyroid status in various degrees of protein-calorie malnutrition in children.

The thyroid functional parameters of 102 children with protein-calorie malnutrition (PCM) classified as undernourished, marasmic, kwashiorkor and marasmic-kwashiorkor were studied by measuring the serum T4, T3, T3 percentage uptake (T3%UT), free thyroxine index (FTI), and (in a few subjects) TSH. Total plasma proteins, albumin and globulin were also estimated. T4 was increased markedly in the undernourished children and significantly decreased in kwashiorkor and marasmic-kwashiorkor groups. There was a consistent and significant fall in T3 levels of all PCM children. From normal values, the fall in T3 levels was progressive in the order of undernourished, marasmic, kwashiorkor and the marasmic-kwashiorkor states. The T3%UT was increased above normal in the marasmic, kwashiorkor and marasmic-kwashiorkor conditions. The FTI decreased somewhat in marasmus and kwashiorkor groups and was very low in marasmic-kwashiorkor. Total protein and albumin levels were above normal in the undernourished but became markedly depressed in the marasmic-kwashiorkor children. The changes in the levels of both T4 and T3 in our observations are well correlated with the levels of plasma proteins in the undernourished, marasmic and kwashiorkor states but not in the marasmic-kwashiorkor group.

Child, Preschool↗
PubMed1983

Hallucinations in Kenyan schizophrenic patients.

Eighty Kenyan 'psychotic' patients were screened using the New Haven Schizophrenic Index (NHSI) and were all studied for hallucinations using standardised definitions. Fifty-one of the patients were NHSI positive and the rest NHSI negative. Sixty-one percent of the NHSI positive had hallucinations in one or more modalities as compared with 31% of the NHSI negative group. Of the NHSI positive 51% had auditory hallucinations directly to the patient, 43% had visual hallucinations and 25% had olfactory hallucinations. These results are compared and contrasted with the very few similar observations made elsewhere.

Adolescent↗
PubMed1983

Schneider's first rank symptoms of schizophrenia in Kenyan patients.

Eighty 'psychotic' patients admitted to Mathare Psychiatric Hospital, Nairobi, were screened using the New Haven Schizophrenic Index (NHSI). Fifty-one (64%) of these were positive and the rest negative. Of those positive 73% had First Rank Symptoms (FRS) of schizophrenia as opposed to only 24% in the group negative for schizophrenia. This difference is highly significant (P less than 0.001). The commonest individual FRS were thought echo, thought insertion, delusional mood and auditory hallucinations in third person. The frequency distribution of FRS had no relation to sex or age. These results are compared and contrasted with the findings of similar studies in various cultures.

Adolescent↗