Alterations in heart and kidney membrane phospholipids in hypertension as observed by 31P nuclear magnetic resonance

Abnormalities of phospholipids in hypertension have previously been described in human erythrocyte, platelet, and plasma lipoproteins. Since the heart and kidney are adversely affected by hypertension, we investigated possible alterations in their membrane phospholipids, which could play a role in the derangement of intracellular ion balance widely observed in hypertension. The phospholipid compositions of heart and kidney from spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats were determined by using 31P nuclear magnetic resonance (NMR) spectroscopy. Absolute contents of all phospholipids in hypertensive hearts and kidneys were significantly higher than in normotensive hearts and kidneys. Expressed as a fraction of total phospholipid, cardiolipin (CL) and phosphatidylethanolamine plasmalogen (PEp) were significantly increased in SHR hearts compared to WKY hearts (CL and PEp were 7.95+/-0.22% and 13.16+/-0.35% in SHR vs. 7.01+/-0.20% and 11.19+/-0.42% in WKY rats, P< or =0.05), but phosphatidylethanolamine (PE) and phosphatidylcholine (PC) were significantly decreased in SHR (PE and PC were 22.46+/-0.37% and 44.81+/-0.43% in SHR vs. 24.02+/-0.44% and 46.01+/-0.50% in WKY rats, P< or =0.05). In the phospholipids extracted from rat kidneys, the percentage of PE was significantly higher for SHR than for WKY rats (20.37+/-0.60% vs. 18.43+/-0.37%, P< or =0.05), while PEp and phosphatidylserine (PS) were significantly lower for SHR (PEp and PS were 10.22+/-0.36% and 8.42+/-0.28% in SHRs vs. 11.29+/-0.36% and 9.71+/-0.40% in WKY rats, P< or =0.05). The above alterations in phospholipid composition might contribute to the higher oxygen consumption in the hypertensive heart and abnormal intracellular ion concentrations and ion transport in the heart and the kidney in hypertension.     

The ATP synthase of Trypanosoma brucei is developmentally regulated by an inhibitor peptide

The Trypanosoma brucei ATP synthase, like those of other organisms, is composed of two moieties, the membrane bound F0 and the catalytic F1 with each of these parts comprised of multiple subunits. In addition, an endogenous inhibitor peptide of the ATP synthase has been identified from a variety of sources. Previous reports have suggested that the Trypanosoma brucei ATPase may not possess such an inhibitor. Recently, we have isolated an inhibitor peptide fraction from the procyclic form of Trypanosoma brucei by modification of a previously published procedure. This fraction is composed of two dominant polypeptides with estimated molecular weights of 14,000 and 12,000 and an additional polypeptide of 15,000 that may or may not be functionally required. Antibodies raised to the smallest polypeptide showed strong cross reactivity with the other two polypeptides, suggesting that they are related. Antibodies to rat liver inhibitor peptide show cross reactivity with the same polypeptides in crude fractions. The inhibitor peptide fraction strongly suppresses the ATPase activity of membrane bound ATPase in a Mg(2+)-dependent manner and is cold and heat stable. Using antibodies to the smallest polypeptide and rat liver inhibitor peptide we have shown in crude extracts from the three experimental life cycle stages of T. brucei that the inhibitor peptide(s) is developmentally regulated to a modest extent. The pattern of regulation is opposite of the pattern seen for the ATP synthase complex. This suggests that the ATP synthase is stringently controlled in T. brucei in a unique way.     

Wide bandwidth, high-repetition-rate optoelectronic modulation of millimetre waves in GaAs waveguide

The generation of ultrashort, chirped and coherent millimetre-wave pulses by an optical method is reported. Using this technique, the modulation of millimetre-wave signals at 94 GHz with a modulation bandwidth in excess of 1 GHz is readily achievable.     

Overexpression of cyclin D1 and cdk4 in tumorigenesis of sporadic hepatoblastomas

We have shown previously that normal B cells share, with Epstein-Barr virus-transformed and malignant B cells, the ability to activate the alternative pathway (AP) of complement in vitro, resulting in the deposition of C3 fragments on the cell surface. Complement receptor type 2 (CR2, CD21) has been implicated directly as the site for formation of an AP convertase, which provides nascent C3b for deposition at secondary sites on the B-cell surface. In the present study, we have examined C3 fragment deposition in vitro in more detail by (1) assessing the importance of locally generated C3b for the deposition process, (2) investigating whether CR2 is the sole requirement for conferring AP activation capacity on a cell, and (3) determining whether CR2's function, as an AP activator, has different structural requirements from ligand binding. Increasing the availability of native C3, by increasing the serum (NHS) concentration, resulted in enhanced C3 fragment deposition on the B cells, whereas use of factor 1-depleted NHS, which showed massive fluid phase C3 conversion during the incubation, diminished the deposition. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting of untreated and hydroxylamine-treated lysates from B cells, after in vitro activation, revealed that the majority of C3 fragments (primarily iC3b and C3dg) had been covalently bound to the cell surface. Transfection of COS cells with wild-type CR2 or a deletion mutant lacking 11 of the molecule's 15 homologous domains, but retaining the ligand-binding site, revealed that expression of intact CR2 conferred a 12-fold increase in AP-activating capacity on these cells, while no increase in AP activity was apparent on cells transfected with the mutant CR2.     

Viral encephalitis in children: detection with technetium-99m HMPAO brain single-photon emission CT and its value in prediction of outcome

PURPOSE: To assess the role of regional cerebral blood flow measured by technetium-99m hexamethyl propyleneamine oxime (HMPAO) brain single-photon emission CT (SPECT) in viral encephalitis of children. METHODS: Eighteen children diagnosed as having viral encephalitis (12 Epstein-Barr virus, 4 herpes simplex virus, and 2 Japanese B virus) underwent Tc-99m HMPAO brain SPECT and brain MR and/or CT. RESULTS: During the acute episode, 4 (22%) of the 18 patients had localized abnormality on brain MR and/or CT. Tc-99m HMPAO brain SPECT in the acute phase showed that 17 (94%) of the 18 patients had increased regional cerebral blood flow and 1 (6%) of the 18 children had a normal brain SPECT. Follow-up brain SPECT was performed at least 15 days after the acute episode. In 17 patients with abnormal first brain SPECT, 12 (71%) had normal second brain SPECT and 5 (29%) had decreased regional cerebral blood flow. The group of patients with normal regional cerebral blood flow on the follow-up brain SPECT had a better outcome than the group of patients with decreased regional cerebral blood flow. CONCLUSIONS: (a) The Tc-99m HMPAO brain SPECT was abnormal more often than CT or MR in children with acute viral encephalitis and provided better location. (b) In acute episodes of encephalitis, most patients showed locally increased regional cerebral blood flow. (c) After acute episodes, the regional cerebral blood flow returned to normal in most cases. (d) A normal Tc-99m HMPAO brain SPECT in the subacute phase usually indicates a good clinical outcome (no neurologic defect) 1 year after the acute illness in children with viral encephalitis.     

A study of the anodic dissolution of gold in concentrated KCN solution

The kinetics of anodic dissolution of gold in concentrated potassium cyanide solution was investigated. The mechanism was found to be with the second step being the rate determining step. Ultrasonic agitation increased the dissolution rate five-fold. The mechanism however, remained unchanged. From current efficiency measurement, it was observed that no auric ions existed in the dissolution process.     

A network model for the diffusion-convection equation

In the past network models have been used frequently to simulate the Laplace's, wave and diffusion equations. In this paper the application of the network model is further extended to include the diffusion-convection equation. the time-dependent diffusion-convection equation is first modelled by an RC electric network from which a set of ODEs is derived. Numerical experiments are then performed to compare the network model and the method of lines in solving the one-dimensional linear diffusion-convection equation and the Burgers' equation where highly non-linear network components are required. It is shown that, for the former problem, the network method has improved accuracy for low Peclet numbers. At high Peclet numbers the behaviour of the network method resembles that of the method of lines (MOL) with upstream-differencing. Spurious oscillations are absent. Computing time required to solve the network is slightly less than that for the MOL. For the Burgers' equation, the network method shows a substantial improvement over the MOL in terms of accuracy with no oscillations but requires longer computing time.     

Identification and characterization of epitopes on Cyn d I, the major allergen of Bermuda grass pollen

BACKGROUND: We identified three epitopes on Cyn d I by using four anti-Cyn d I monoclonal antibodies (MoAbs). METHODS: In a cross-inhibition binding assay, the binding of MoAbs 1-61 and 10-7 to Cyn d I was completely blocked by each other but not by MoAbs 4-37 and 11-7; the binding of MoAb 4-37 and MoAb 11-7 to Cyn d I was inhibited by themselves but not by other MoAbs. The epitope recognized by MoAbs 1-61 and 10-7 is designated as E1, and those recognized by MoAbs 4-37 and 11-7 are designated as E2 and E3, respectively. RESULTS: In a radioallergosorbent inhibition assay, we found that MoAbs 1-61 and 4-37 (1:50 diluted) can inhibit the binding of human Immunoglobulin Es to Cyn d I by more than 30%, whereas MoAb 11-7 was less efficient (reduced by only 6%). These results suggest that both E1 and E2 are major allergenic epitopes but that E3 is only a minor one. Further characterization of E1 and E2 reveals that they are labile in alkaline but resistant to acid and sodium periodate treatments. Moreover, E1 is heat-labile, but guanidine- and urea-sensitive, whereas E2 is not. Both E1 and E2 lost their antigenicity after reduction and alkylation. CONCLUSIONS: Results of the present study provide important information on the physicochemical properties of major allergenic epitopes on Cyn d I, which may be useful for future development of therapeutic peptides for patients allergic to Bermuda grass pollen.     

A study of the Pd/C catalyst for synthesis of hydroxylamine

Palladium dispersed on active carbon (Pd/C) is used as a catalyst in the synthesis of hydroxylamine. Alkaline precipitation was used to prepare the catalyst. It was found that the controlling factor was the size of palladium crystal, which in turn was chiefly determined by the PdCl₄^2-/Pd(OH)₂ conversion stage. The sintering and crystal growth of Pd was the main reason for the decay of the catalyst. The sintering mechanism was found to follow the Ostwald ripening model.     

Sex pheromone components from asian corn borer,Ostrinia furnacalis (Hubner) (Lepidoptera: Pyralidae) in Taiwan

The female sex pheromone of the Asian com borer,Ostrinia furnacalis, widespread in Taiwan, was confirmed as (Z)-12-tetradecenyl acetate and its geometric isomer (E)-12-tetradecenyl acetate in a ratio of ca. 31 by gas chromatography and gas chromatography-mass spectrometry in selected ion monitoring mode. Males were attracted by the mixture of these two synthetic components in the field, but the attractiveness was less than by virgin females. The presence of minor components in the sex pheromone was therefore suggested.