A model for the C5a receptor and for its interaction with the ligand

A printer's error was introduced into the title of this articlewhen it was in press. The correct title is as follows. A model for the C5a receptor and for its interaction with theligand^* An omission was also made on the second line of the first columnon page 769. This and the subsequent four lines should readas follows. pairing of Cys86(B) with Cys109(C) or Cys285(G), but stronglysuggest that with either Cys293 or Cys294(G). A choice can bemade with arguments given below. Pairing with Cys285(G), forinstance, would require a vertical relative shift of two helixturns which would immerse polar side chains in the membrane.     

矿井提升机TKD电控系统的技术改造

我矿副井提升机为斜井双钩串车平车场提升机，主要提升任务是升降物料、设备和提升矸石。为2JK-2．5／30双滚筒单绳缠绕式交流提升机，配套TKD-A2-1186(Ⅰ)型电气控制系统，配置KZG(D)SCR动力制动电源装置，主电动机型号为JRl37-10，额定功率为15．5kW，额定转速为585r／min。     

Evaluation of low density spine software for the assessment of bone mineral density in children

Pediatric dual-energy X-ray absorptiometry spine scans often cannot be analyzed with standard software due to a failure to identify the bone edges of low density vertebrae. Low density spine (LDS) software improves bone detection compared with standard software. The objective of this study was to compare bone mineral density (BMD) measurements obtained with the standard and LDS software in 27 healthy nonobese, 32 obese, and 41 chronically ill children, ages 2-18 years. Lumbar spine (L1-L4) BMD, measured by standard analysis, ranged from 0.531-1.244 gm/cm2. Reanalysis with the LDS software resulted in a systematic increase (mean +/- SD) in estimated bone area of 17.0+/-5.0%, an increase in bone mineral content of 6.1+/-6.3%, and a mean decrease in BMD of 8.7+/-1.7% (all p < 0.001). This resulted in a mean decrease in BMD Z score of 0.7+/-0.2. Linear regression models, predicting standard BMD from LDS BMD, were fit for the three subject groups (R2 = 0.993-0.995). Small differences in slopes were detected across groups (p = 0.07); LDS BMD predicted higher standard BMD in obese subjects. In conclusion, LDS analysis resulted in a clinically significant decrease in measured BMD. The association between analysis methods was exceptionally high (R2 > 0.99), indicating that LDS BMD accurately predicts standard BMD. Although LDS BMD in obese subjects predicts higher standard BMD results than in nonobese subjects, the small difference is of questionable clinical significance. LDS software is a useful tool for the assessment of BMD in children.     

The role of transmembrane domain 2 in cation transport by the Na-K-Cl cotransporter

The human and shark Na-K-Cl cotransporters (NKCC), although 74% identical in amino acid sequence, exhibit marked differences in ion transport and bumetanide binding. We have utilized shark-human chimeras of NKCC1 to search for regions that confer the kinetic differences. Two chimeras (hs3.1 and its reverse sh3.1) with a junction point located at the beginning of the third transmembrane domain were examined after stable transfection in HEK-293 cells. Each carried out bumetanide-sensitive 86Rb influx with cation affinities intermediate between shark and human cotransporters. In conjunction with the previous finding that the N and C termini are not responsible for differences in ion transport, the current observations identify the second transmembrane domain as playing an important role. Site-specific mutagenesis of two pairs of residues in this domain revealed that one pair is indeed involved in the difference in Na affinity, and a second pair is involved in the difference in Rb affinity. Substitution of the same residues with corresponding residues from NKCC2 or the Na-Cl cotransporter resulted in cation affinity changes, consistent with the hypothesis that alternative splicing of transmembrane domain 2 endows different versions of NKCC2 with unique kinetic behaviors. None of the changes in transmembrane domain 2 was found to substantially affect Km(Cl), demonstrating that the affinity difference for Cl is specified by the region beyond predicted transmembrane domain 3. Finally, unlike Cl, bumetanide binding was strongly affected by shark-human replacement of transmembrane domain 2, indicating that the bumetanide-binding site is not the same as the Cl-binding site.     

Synthesis of charged phenyl radicals and biradicals by laser photolysis in a Fourier-transform ion cyclotron resonance mass spectrometer

The feasibility of generating substituted phenyl radicals and biradicals (with a charged substituent) in the gas phase by laser photolysis was examined by using a Fourier-transform ion cyclotron resonance mass spectrometer. The precursors were generated by ipso-substitution of a halogen atom in the radical cation of a di- or trihalobenzene by various nucleophiles. Photolytic cleavage of the remaining carbon-halogen bond(s) with 266-nm radiation was found to produce many substituted phenyl radicals in greater yields than the earlier employed method, sustained off-resonance irradiated collision-activated dissociation (SORI-CAD). Furthermore, ion generation by photolysis leads to isomerization less often than collisional activation. Finally, not only phenyl-bromine and phenyl-iodine but also certain phenyl-chlorine bonds can be cleaved by photolysis, whereas the synthetic utility of SORI-CAD appears to be largely limited to the cleavage of phenyl-iodine bonds. Hence, laser photolysis greatly expands the variety of substituted phenyl radicals and biradicals that can be synthesized inside a mass spectrometer.     

125I-Tyr1]biphalin binding to opioid receptors of rat brain and NG108-15 cell membranes

Mono iodinated analogues of biphalin [(Tyr-D-Ala-Gly-Phe-NH-)2], both nonradioactive [I-Tyr1]biphalin and radioactive [125I-Tyr1]biphalin have been synthesized. The radioligand binding profiles of these compounds for two types of tissues, rat brain membranes, and NG108-15 cell membranes were identical to the parent biphalin. This is additional evidence for the hypothesis that biphalin behaves like a monomeric ligand and that only one intact tyrosine is necessary for high biological activity. The second tyrosine could be used for successful radioiodination which may greatly simplify biochemical and pharmacological studies of biphalin. The results of receptor binding studies show that the binding of both biphalin and [I-Tyr1]biphalin to the delta and mu opioid receptors are not independent. [125I-Tyr1]Biphalin binds to delta receptors as shown in NG108-15 cell membranes. Nevertheless, [125I]biphalin binding to delta receptors in rat brain membranes was hardly evident and mu receptor binding predominated or at least was much more readily detectable in this preparation.     

An evaluation of the effect of an alpha hydroxy acid-blend skin cream in the cosmetic improvement of symptoms of moderate to severe xerosis, epidermolytic hyperkeratosis, and ichthyosis

It has been observed that the occurrence of respiratory complications and diarrhoea among measles cases has changed over time but this change has not been quantified. A study was carried out in the city of Gweru, Zimbabwe, to quantify these changes. Rates of respiratory complications and diarrhoea among measles cases were determined in each year for the period 1968-89. It was found that mean rates of respiratory complications and diarrhoea during 1968-78 were 17.2 per cent (95 per cent CI = 11.6-22.8) and 5.2 per cent (95 per cent CI = 0-11) respectively while during 1979-89, mean rates of respiratory complications and diarrhoea were 6.5 per cent (95 per cent CI = 1-12.1) and 16.4 per cent (95 per cent CI = 10.1-22.0) respectively. Analysis of variance (ANOVA) to determine the main effects and the interaction showed that the main effects were not statistically significant (F = 0.01, d.f.1,2 = 1,40, p = 0.935; and F = 0.13, d.f.1,2 = 1,40, p = 0.725 respectively) Meanwhile the interaction term of complications and period was statistically significant (F = 15.7, d.f.1,2 = 1,40, p < 0.001). It was concluded that a change in rates of respiratory complications and diarrhoea had occurred among measles cases. It is suggested that the increase in vaccination coverage in 1979-89 and the shift in age at infection to older age groups in the same period may have brought about this change through selective suppression of respiratory complications among measles cases.