Superior cavopulmonary anastomosis suppresses the activity and expression of pulmonary angiotensin-converting enzyme.

BACKGROUND: Superior cavopulmonary anastomosis is widely used for palliation of various forms of univentricular heart defects. However, clinically significant pulmonary arteriovenous malformations develop in 15% to 25% of patients after surgery. OBJECTIVE: To assess altered regulation of pulmonary vascular tone caused by superior cavopulmonary anastomosis in an ovine model. METHODS: Lambs, aged 35 to 45 days, underwent an end-to-end anastomosis of the superior vena cava to the right pulmonary artery. In age-matched controls, a sham operation was performed. Arteriovenous malformations were detectable by contrast echocardiography by 8 weeks after surgery. Animals (n = 24) were studied at various time points after the operations. Expression of angiotensin-converting enzyme messenger RNA, protein levels, and enzyme activity were measured in lung homogenates. Levels of angiotensin II were measured by enzyme-linked immunosorbent assay. RESULTS: Expression of angiotensin-converting enzyme messenger RNA and protein was significantly reduced at 1 to 5 weeks after superior cavopulmonary anastomosis. Angiotensin-converting enzyme activity in the right lung of animals subjected to superior cavopulmonary anastomosis was reduced 86% +/- 1% (standard deviation) compared with control values at 1 week (P =.003) and 77% +/- 8.5% at 2 weeks (P <.001) after surgery. This correlated with a 59% +/- 3.5% (P =.007) reduction in angiotensin II levels up to 5 weeks after cavopulmonary anastomosis. By 15 weeks after the operations, angiotensin II levels were equivalent to control levels (P =.19). CONCLUSIONS: Superior cavopulmonary anastomosis causes an early reversible reduction in activity and expression of angiotensin-converting enzyme, resulting in decreased circulating levels of the vasoconstrictor angiotensin II. These results suggest that the ability of the pulmonary endothelium to regulate vascular tone is inhibited after superior cavopulmonary anastomosis. Dilation of the affected vasculature induced by cavopulmonary anastomosis may contribute to the disordered vascular remodeling observed in this setting.

Patterns of prescriptions and drug use in two tertiary hospitals in Delhi.

The study was carried out to assess prescribing trends in outpatients at Dr. R.P. Centre for Ophthalmic Sciences (RPC) and other OPD's of All India Institute of Medical Sciences (AIIMS) and Safdarjung hospitals, two premier hospitals in Delhi. Prescriptions of 500 patients were audited and analysed under heads of average number of drugs per patient, percentages of drugs prescribed by generic name, antibiotics, injections, drugs from WHO recommended essential drug list, availability of drugs etc. using WHO basic drug indicators. Prescription analysis showed that 75 to 95% drugs were prescribed from essential drug list. The average number of drugs per prescription was 1.42 to 4.07. Percentage of antibiotics prescribed varied from 14.39% to 22.28%. The use of injections was from nil to 4.4%. Availability of drugs was however, not satisfactory. Though maximum drugs were prescribed from essential drug list, the results indicate that there is a considerable scope for improving prescribing habits according to rational drug use and to provide a feed back to hospital authority for making maximum number of drugs available to the patients.

Purification and characterization of cytosolic pyruvate kinase from developing seeds of Brassica campestris L.

Cytosolic pyruvate kinase (ATP: Pyruvate phosphotransferase, EC 2.7.1.40; PKc) was purified to apparent homogeneity with about 22% recovery from developing seeds of Brassica campestris using (NH4)2SO4 fractionation, DEAE-cellulose chromatography, gel filtration through Sepharose-CL-6B and affinity chromatography through reactive Blue Sepharose-CL-6B. The purified enzyme with molecular mass of about 214 kDa was a heterotetramer with subunit molecular mass of 55 and 57 kDa. The enzyme showed maximum activity at pH 6.8 and absolute requirement for a divalent (Mg2+) and a monovalent (K+) cation for activity. Typical Michaelis-Menten kinetics was obtained for both the substrates with Km values of 0.10 and 0.11 mM for PEP and ADP, respectively. The enzyme could also use UDP or GDP as alternative nucleotides, but with lower Vmax and lesser affinities. The enzyme was inhibited by glutamate, glutamine, fumarate, citrate, isocitrate, oxalate, 2-PGA, ATP, UTP and GTP and activated by glucose-6-phosphate, fructose-1,6-bisphosphate and Pi, suggesting its regulation mainly by TCA cycle intermediates and the cellular need for carbon skeletons for amino acid biosynthesis. ATP inhibition was of competitive type with respect to PEP and non-competitive with respect to ADP. Similarly, oxalate inhibition was also of competitive type with respect to PEP and non-competitive with respect to ADP. Initial velocity and product inhibition studies except for pyruvate inhibition were consistent for a compulsory-ordered tri-bi mechanism.

Purification and characterizaton of plastidic pyruvate kinase from developing seeds of Brassica campestris L.

Plastidic pyruvate kinase (ATP: pyruvate phosphotransferase, EC 2.7.1.40) was purified to near homogeneity as judged by native PAGE with about 4% recovery from developing seeds of Brassica campestris using (NH4)2SO4 fractionation, DEAE-cellulose chromatography, gel filtration through Sepharose-CL-6B and affinity chromatography through reactive blue Sepharose-CL-6B. The purified enzyme having molecular mass of about 266 kDa was quite stable and showed a broad pH optimum between pH 6.8-7.8. Typical Michaelis-Menten kinetics was obtained for both the substrates with K(m) values of 0.13 and 0.14 mM for PEP and ADP, respectively. The enzyme could also utilize CDP, GDP or UDP as alternative nucleotide to ADP, but with lower Vmax and higher K(m). The enzyme had an absolute requirement for a divalent and a monovalent cation for activity and was inhibited by oxalate, fumarate, citrate, isocitrate and ATP, and activated by AMP, aspartate, 3-PGA, tryptophan and inorganic phosphate. ATP inhibited the enzyme competitively with respect to PEP and non-competitively with respect to ADP. Similarly, oxalate inhibition was also of competitive type with respect to PEP and non-competitive with respect to ADP. This inhibition by either ATP or oxalate was not due to chelation of Mg2+, as the inhibition was not relieved on increasing Mg2+ concentration even upto 30 mM. Initial velocity and product inhibition studies demonstrated the reaction mechanism to be compulsory ordered type. The enzyme seems to be regulated synergistically by ATP and citrate.

Child population and attitudes towards children in an arid village.

PIP: Examines the socioeconomic characteristics of the child population of an arid village. A representative arid village in Jodhpur district was selected; information was collected by means of participant observation and interview. Informal discussions were also conducted with villagers. A total of 10% of the households of different castes were sampled. The 1971 census indicated that children under 15 years of age accounted for 42% of the Indian population, and as much as 45% of the population of the 12 arid districts of Rajasthan. In these villages child marriage is the norm, and there is little or no effort to control the size of families. Moreover, there is a tendency to actively desire a large number of children, particularly boys. This attitude is changing--parents now regard 3 to 5 offspring to be a reasonable amount. Female children are less valued than their male counterparts and subsequently have a higher mortality rate. Feeding practices give priority to boys, even over the head of household, with girls enjoying priority over the adult male, and the adult female being placed last. Children's health is often ar risk from easily preventable and communicable diseases; treatments for these diseases are in many cases traditional remedies. Their poor physical condition notwithstanding, children are treated as important members of the arid zone society, but some of the deep seated feelings concerning children and their welfare constitute part of the problem of development for children in arid regions of India.^ieng

Characterization of seed storage proteins of urdbean (Vigna mungo).

Dehulled and defatted flour of urdbean (Vigna mungo), Var T-9, contained 25% protein with maximum contribution by globulins (63%). Albumins and glutelins contributed 12% and 21% respectively, whereas prolamins were present only in traces (1%). Globulins were further fractionated into legumin and vicilin type proteins which were present in the ratio of 4:1. All the protein fractions were heterogenous in nature as revealed by high performance liquid chromatography. SDS-polyacrylamide gel electrophoresis revealed the total protein sample to contain 21 different components with molecular weights ranging from 8.92 to 117.49 kd. Albumins, globulins, prolamins and glutelins resolved into 4, 8, 6 and 13 different sized components of molecular weights ranging from 10.23 to 25.53, 10.84 to 112.72, 10.33 to 51.52 and 8.91 to 112.72 kd, respectively. Amino acid analysis of all fractions revealed that glutamic acid was present in maximum concentration followed by aspartic acid and lysine. Just like other pulse proteins, the urdbean proteins were also deficient in sulphur containing amino acids.

Purification and characterization of dihydroxyacetone phosphate reductase from immature seeds of Brassica campestris L.

Dihydroxyacetone phosphate reductase (DHAP reductase) was purified to apparent electrophoretic homogeneity with about 24% recovery from immature seeds of Brassica campestris using (NH(4))(2)SO(4) fractionation, affinity chromatography, gel filtration and adsorption chromatography. The purified enzyme with molecular mass of about 62 kDa was a dimer with subunit molecular mass of 32 kDa. The enzyme exhibited maximum activity at pH 7.5 and was highly specific for NADH and DHAP. Typical Michaelis-Menten kinetics was obtained for both the substrates with K(m) values of 3.3 and 26.6 &mgr;M for NADH and DHAP, respectively. The enzyme did not require any metal ion for its activity. Rather, the activity was inhibited by Na(+), K(+), Mn(2+), Mg(2+,) and Ca(2+). ATP and fructose-1,6-P(2) inhibited the enzyme non-competitively with respect to DHAP with K(i) values of 0.96 and 1.3 mM, respectively. Substrate interaction kinetics and product inhibition studies were consistent with compulsory-ordered bi-bi reaction mechanism with NADH being the first substrate to bind and NAD being the last product to dissociate. Based on the properties discussed here, it appears that the enzyme probably functions for the production of glycerol-3-P from DHAP.