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Diffraction quality crystals are essential for crystallographic studies of protein structure, and the production of poorly diffracting crystals is often regarded as a dead end in the process. Here we show a dramatic improvement of poorly diffracting DsbG crystals allowing high-resolution diffraction data measurement. Before dehydration, the crystals are fragile and the diffraction pattern is streaky, extending to 10 A resolution. After dehydration, there is a spectacular improvement, with the diffraction pattern extending to 2 A resolution. This and other recent results show that dehydration is a simple, rapid, and inexpensive approach to convert poor quality crystals into diffraction quality crystals.

On the basis of the avid uptake of radioiodinated benzamides by melanoma cells, (99m)Tc complexes containing the structural elements of N-(dialkylaminoalkyl)benzamide pharmacophores have been synthesized and evaluated in vitro and in vivo for melanoma uptake. One of the complexes Tc-12 containing the ligand 4-(S-benzoyl-2-thioacetyl-glycyl-glycylamido)-N-(2-diethylaminoethyl)benzamide (11) displayed the highest melanoma uptake. The 1-h melanoma uptake values and the corresponding blood counts indicate an interdependence of tumor uptake and bioavailability of the (99m)Tc complexes.

N-(2-Mercaptoethyl)picolylamine (MEPAH) was studied as a potentially biologically relevant ligand for the "fac-[M(CO)(3)](+)" core (M = Re, (99)Tc, (99m)Tc). To this end, the complex Re(CO)(3)(MEPA) was synthesized. The reaction of MEPAH with fac-[Re(CO)(3)(MeCN)(3)](+) took place over the course of seconds, showing the high affinity possessed by this ligand for the "fac-[Re(CO)(3)](+)" core. A single-crystal X-ray diffraction study was performed confirming the nature of Re(CO)(3)(MEPA), a rare mononuclear rhenium(I) thiolate complex. Additional exploration into derivatization of the ligand backbone has afforded the analogous N-ethyl complex, Re(CO)(3)(MEPA-NEt). The high affinity of the ligand for the metal coupled with the ease of its derivatization implies that utilization of this ligand system for the purposes of (99m)Tc-radiopharmaceutical development is promising.

The reduction of ammonium pertechnetate with bis(diphenylphosphino)methane (dppm), and with diphenyl-2-pyridyl phosphine (Ph(2)Ppy), has been investigated. The neutral Tc(II) complex, trans-TcCl(2)(dppm)(2) (1), has been isolated from the reaction of (NH(4))[TcO(4)] with excess dppm in refluxing EtOH/HCl. Chemical oxidation with ferricinium hexafluorophosphate results in formation of the cationic Tc(III) analogue, trans-[TcCl(2)(dppm)(2)](PF(6)) (2). The dppm ligands adopt the chelating bonding mode in both complexes, resulting in strained four member metallocycles. With excess PhPpy, the reduction of (NH(4))[TcO(4)] in refluxing EtOH/HCl yields a complex with one chelating Ph(2)Ppy ligand and one unidentate Ph(2)Ppy ligand, mer-TcCl(3)(Ph(2)Ppy-P,N)(Ph(2)Ppy-P) (3). The cationic Tc(III) complexes, trans-[TcCl(2)(Ph(2)P(O)py-N,O)(2)](PF(6)) (4) and trans-[TcCl(2)(dppmO-P,O)(2)](PF(6)) (5) (Ph(2)P(O)py = diphenyl-2-pyridyl phosphine monoxide and dppmO = bis(diphenylphosphino)methane monoxide), have been isolated as byproducts from the reactions of (NH(4))[TcO(4)] with the corresponding phosphine. The products have been characterized in the solid state and in solution via a combination of single-crystal X-ray crystallography and spectroscopic techniques. The solution state spectroscopic results are consistent with the retention of the bonding modes revealed in the crystal structures.

The I allele of the angiotensin I-converting enzyme (ACE) gene is associated with lower ACE activity and endurance performance; an excess occurs in elite distance runners, rowers, and mountaineers, perhaps secondary to enhanced muscle efficiency. Conversely, the D allele is associated with training-related strength gain and elite power-oriented performance secondary to increased ACE and angiotensin II, a growth factor.

Optimised gradient reversed-phase high-performance liquid chromatography electrospray ionisation mass spectrometry (LC/MS) methods, in combination with a [3H]-brevetoxin binding assay (RLB), revealed multiple ciguatoxins in a partially purified extract of a highly toxic Lutjanus sebae (red emperor) from the Indian Ocean. Two major ciguatoxins of 1140.6 Da (I-CTX-1 and -2) and two minor ciguatoxins of 1156.6 Da (I-CTX-3 and -4) were identified. Accurate mass analysis revealed that I-CTX-1 and -2 and Caribbean C-CTX-1 had indistinguishable masses (1140.6316 Da, at 0.44 ppm resolution). Toxicity estimated from LC/MS/RLB responses indicated that I-CTX-1 and -2 were both approximately 60% the potency of Pacific ciguatoxin-1 (P-CTX-1). In contrast to ciguatoxins of the Pacific where the more oxidised ciguatoxins are more potent, I-CTX-3 and -4 were approximately 20% of P-CTX-1 potency. Interconversion in dilute acid or on storage, typical of spiroketal and hemiketal functionality found in P-CTXs and C-CTXs, respectively, was not observed to occur between I-CTX-1 and -2. The ratio of CTX-1 and -2 varied depending on the fish extract being analysed. These results suggest that I-CTX-1 and -2 may arise from separate dinoflagellate precursors that may be oxidatively biotransformed to I-CTX-3 and -4 in fish.

Purpose: To synthesize a number of analogues of Leu-enkephalin with different lipophilicities and to develop an LC-MS method for determining the Caco-2 cell permeability values of these compounds., Methods: A number of sugar and sugar plus lipoamino acid analogues of Leu-enkephalin were synthesized by solid-phase and solution methods. An LC-MS method was developed for analyzing the Caco-2 cell assay samples and validated against the traditional method using radiolabelled compounds., Results: A sensitive and specific LC-MS assay was developed. Standard curves were linear in the range of 0.025-5 microM. Apparent permeability values determined by LC-MS and liquid scintillation counter were identical, for both a hydrophilic drug, cephalexin and a lipophilic Leu-enkaphalin analogue. Caco-2 permeability values for the analogues of Leu-enkephalin were determined and it was found that attachment of sugar or sugar and lipoamino acid to the Leu-enkephalin peptide resulted in an increase in the apparent permeability values compared to the native peptide, which was not transported across the Caco-2 cell monolayers., Conclusions: A rapid, generic LC-MS method for analyzing a range of compounds was developed. Attachment of a sugar or sugar and lipoamino acid to Leu-enkephalin improves the apparent permeability across Caco-2 cell monolayers.

We studied the variation in toxin profiles of purified extracts of 10 individual specimens and two pools of ciguateric Caranx latus. High-performance liquid chromatography/mass spectrometry (HPLC/MS) identified in all individual samples at least seven Caribbean ciguatoxins (C-CTXs) comprising C-CTX-1 and its epimer C-CTX-2 ([M+H](+) m/z 1141.58), and five new C-CTX congeners with pseudo-molecular ions at m/z 1141.58, 1143.60, 1157.57, 1159.58, and 1127.57. In some samples, additional C-CTX isomers were detected with [M+H](+) ions at m/z 1141.58 (two), 1143.60 (one) and 1157.57 (two). The two low-toxic pools contained only four to six ciguatoxins. The comparison in relative proportions of four different mass classes ([M+H](+) at m/z 1141, 1143, 1157 and 1127) showed that the group at m/z 1157 increased (2-20%) with flesh toxicity. More than 80% of group m/z 1141 comprised C-CTX-1, C-CTX-2 and their isomer C-CTX-1a whose level in this group correlated with fish toxicity. Contrary to low-toxic fishes, high-risk specimens had C-CTX-1 levels <50% and were subjected to large losses of activity on purification indicating that unstable ciguatoxins were present. A possible conversion of C-CTX-1 into C-CTX-1a was identified when flesh was cooked, without changes in toxicity. In conclusion, HPLC/MS characterised 12 C-CTXs accumulated by C. latus at variable levels.

A new route to low-valent technetium complexes containing multiple acetonitrile ligands has been developed. The reduction of TcCl(4)(PPh(3))(2) with zinc metal dust in acetonitrile results in the formation of [Tc(CH(3)CN)(4)(PPh(3))(2)][Zn(2)Cl(6)](1/2). The hexafluorophosphate salt of the analogous Tc(II) cation can be prepared via chemical oxidation of the Tc(I) species, and the Tc(I) cation can be regenerated via chemical reduction. The compounds have been characterized in the solid state via single-crystal X-ray crystallography, and in solution via a combination of spectroscopic techniques and cyclic voltammetry. The structural parameters found in the two complexes are similar to each other; however, the difference in oxidation state is reflected, as expected, in the spectroscopic results. The electrochemical data, obtained from cyclic voltammograms of Tc(CH(3)CN)(4)(PPh(3))(2)](PF(6))(n)() (n = 1,2), mirror the synthetic results in that both compounds possess a reversible redox couple at -0.55 V versus ferrocene, which has been assigned to the Tc(II)/Tc(I) couple.

We report the isolation and initial characterisation of Indian Ocean ciguatoxin (I-CTX) present in toxic lipid soluble extracts isolated from ciguateric fishes collected off the Republic of Mauritius in the Indian Ocean. Following i.p. injection of this extract, mice displayed symptoms that were similar, though not identical, to those produced by Pacific and Caribbean ciguatoxins (P-CTXs and C-CTXs). Using a radiolabelled brevetoxin (PbTx) binding assay and mouse bioassay guided fractionation, I-CTX was purified by Florisil, Sephadex LH-20 and TSK HW-40S chromatography with good recovery. Isolation to purity was not possible by preparative reversed phase high-performance liquid chromatography (HPLC) due to significant losses of toxicity. However, analytical reversed phase HPLC coupled to an electrospray mass spectrometry detector identified a [M + H](+) ion at m/z 1141.58 which co-eluted with activity that displaced [3H]-PbTx binding to rat brain. This mass corresponded to C-CTX-1, but the fragmentation pattern of I-CTX showed a different ratio of pseudo molecular and product ions. I-CTX was found to elute later than P-CTX-1 but was practically indistinguishable from C-CTX-1 on reversed phase HPLC, while the TSK HW-40S column chromatography differentiated I-CTX from the later eluting C-CTX-1. Taken together, these results indicate that I-CTX is a new ciguatoxin (CTX) responsible for ciguatera caused by reef fish in the Indian Ocean., (Copright 2002 Elsevier Science Ltd.)

Unlabelled: Noninvasive monitoring of gene transfer will benefit basic research and patient care. Most gene-transfer imaging systems do not directly detect the gene of interest, and most do not exploit radiopharmaceuticals that have Food and Drug Administration approval for total-body use. (111)In-Octreotide is used clinically to locate tumors overexpressing primarily somatostatin receptor type 2 (SSTR2). We report the in vitro and in vivo detection of SSTR2 chimeric gene transfer with this radiopharmaceutical., Methods: Full-length SSTR2A was ligated into a vector downstream of a 5' Igkappa leader sequence and the hemagglutinin A (HA) sequence. The vector plus insert was then introduced into HT1080 cells. Igkappa and HA domain functions were confirmed by immunologic methods. Receptor binding was studied in transfected cells incubated with (111)In-octreotide with and without somatostatin-28. Mice bearing tumors produced by transfected cells were injected with (111)In-octreotide for biodistribution and imaging studies., Results: Cell-membrane localization by the amino-terminal Igkappa domain was confirmed by immunofluorescence. The HA domain was identified by enzyme-linked immunosorbent assay, immunofluorescence, and Western blotting analysis with anti-HA antibodies. (111)In-Octreotide detected the SSTR2 portion of the fusion protein in vitro (receptor-binding assay) and in vivo (biodistribution studies and gamma-camera imaging). In addition, in vitro studies using either the anti-HA antibody or (111)In-octreotide correlated with biodistribution and imaging studies when cell clones expressing different levels of the fusion protein were tested. This approach may be feasible clinically because we were able to discern chimeric gene transfer in tumor-bearing animals with (111)In-octreotide at doses similar to those already used in humans., Conclusion: With this method it may be possible to monitor transfer of a gene of interest directly and noninvasively.

The reduction of perrhenate, molybdate and pertechnetate with 2-hydrazinopyridine dihydrochloride in methanol has led to the preparation of a class of complexes containing the {M(eta(1)-NNC(5)H(4)NH(x)())(eta(2)-HNNH(y)()C(5)H(4)N)} core, represented by [TcCl(3)(NNC(5)H(4)NH)(HNNC(5)H(4)N)] (2), [ReCl(3)(NNC(5)H(4)NH)(HNNC(5)H(4)N)] (3), and [MoCl(3)(NNC(5)H(4)NH)(HNNHC(5)H(4)N)] (6). The reaction of 3 with NEt(3) results in the formation of [HNEt(3)][[ReCl(3)(NNC(5)H(4)N)(HNNC(5)H(4)N)].H(2)O (4) by deprotonation of the pyridine nitrogen site. Similarly, the reduction of perrhenate with 2-hydrazino-2-imidazoline hydrobromide has led to the preparation of the analogous [ReCl(3)(NNC(3)H(4)N(2)H)(HNNHC(3)H(4)N(2)H)] (5). Reaction of 3 with pyridine-2-thiol and pyrimidine-2-thiol yields two structurally characterized derivatives with a modified {Re(eta(1)-NNC(5)H(4)N)(eta(2)-HNNC(5)H(4)N)} core, [Re(C(5)H(4)NS)(2)(NNC(5)H(4)N)(HNNC(5)H(4)N)] (8) and [Re(C(4)H(3)N(2)S)(2)(NNC(5)H(4)N)(HNNC(5)H(4)N)] (9), respectively. Reaction of 6 with pyrimidine-2-thiol led to the isolation of the analogous [Mo(C(4)H(3)N(2)S)(2)(NNC(5)H(4)N)(HNNHC(5)H(4)N)] (11) and the seven-coordinate monohydrazine core complex [Mo(C(4)H(3)N(2)S)(3)(NNC(5)H(4)N)].CH(2)Cl(2) (12). In similar fashion, the reaction of 2 with pyridine-2-thiol yielded a complex structurally analogous to 8, [Tc(C(5)H(4)NS)(2)(NNC(5)H(4)N)(HNNC(5)H(4)N)] (7). Crystal data for 3, C(10)H(10)Cl(3)N(6)Re: triclinic, P&onemacr;, a = 7.527(2) Å, b = 7.599(2) Å, c = 13.118(3) Å, alpha = 106.55(3) degrees, beta = 90.28(3) degrees, gamma = 93.83(3) degrees, V = 717.4(4) Å(3), Z = 2. For 4, C(16)H(27)Cl(3)N(7)ORe: orthorhombic, P2(1)2(1)2(1), a = 7.503(2) Å, b = 10.3643(2) Å, c = 30.1590(5) Å, V = 2345.20(6) Å(3), Z = 2. For 5, C(6)H(12)Cl(3)N(8)Re: monoclinic, P2(1)/n, a = 9.093(2) Å, b = 11.105(2) Å, c = 14.295(3) Å, beta = 94.71(3) degrees, V = 1438.6(7) Å(3), Z = 4. For 6, C(10)H(11)Cl(3)N(6)Mo: monoclinic, P2(1)/c, a = 15.366(3) Å, b = 7.804(2) Å, c = 12.378(3) Å, beta = 95.92(3) degrees, V = 1476.4(5) Å(3), Z = 4. For 7, C(20)H(17)N(8)S(2)Tc: monoclinic, P2(1), a = 8.827(2) Å, b = 9.278(2) Å, c = 13.304(3) Å, beta = 98.92(3) degrees, V = 1076.5(5) Å(3), Z = 2, 2564 reflections. For 8, C(20)H(17)N(8)S(2)Re: monoclinic, P2(1), a = 8.848(2) Å, b = 9.190(2) Å, c = 13.293(3) Å, beta = 98.89(3) degrees, V = 1067.9(5) Å(3), Z = 2. For 9, C(18)H(15)N(10)S(2)Re: monoclinic, P2(1), a = 8.796(2) Å, b = 9.008(2) Å, c = 13.208(3) Å, beta = 97.90(3) degrees, V = 1036.6(5) Å(3), Z = 2. For 12, C(18)H(15)N(9)S(3)Cl(2)Mo: monoclinic, P2(1)/n, a = 10.52900(10) Å, b = 15.1116(3) Å, c = 15.8193(3) Å, beta = 108.4790(10) degrees, V = 2387.23(7) Å(3), Z = 4. Complexes 2 and 3 serve as models for the binding of Tc(V)-oxo and Re(V)-oxo species to hydrazinonicotinamide (HYNIC)-conjugated chemotactic peptides. Furthermore, since the use of the pyrimidinethiol coligand in the {(99m)Tc-HYNIC-peptide} radiochemical species results in favorable pharmacokinetics, the thiolate derivatives 8 and 9 provide models for possible modes of interaction of metal-hydrazine cores with coligands in the radiopharmaceutical reagents.

This paper examines the role of clinical supervision in relation to the work of a palliative care nurse, although the issues discussed relate to all nurses whatever specialities. The effects of market forces and organisational culture on the delivery of human service are explored in context. The writer draws on psychoanalytical ego defence construction and existential-phenomenological ideas to throw light on the deliberation. Through a case study illustration the writer makes a case for the development of a safe and effective working relationships helped by clinical supervision and through agreed working arrangements. The discussion concludes with the central recommendation that constructing a safe working environment for clinical supervision, through which to explore the dynamic forces influencing the organisation of health care, transcends methodological considerations. (The writer has changed all names and circumstances).

The organohydrazide chelate complexes M(III)(NNpy)(PPh(3))(2)Cl(2) (1, 3) (M = Re, Tc) have been synthesized using the organohydrazine 2-hydrazinopyridine. The chelated organohydrazide is a diazenido(1-) ligand that forms a five-membered ring with the metal center. An X-ray structural analysis of 1 indicates that there is a delocalized pi-system formed by the chelate ring. These octahedral, d(4) metal complexes have diamagnetic (1)H NMR spectra. Complex 1, C(41.50)H(34)Cl(2)N(3)O(0.5)P(2)Re, crystallizes in the triclinic space group P&onemacr; with a = 10.5549(7) Å, b = 12.2699(8) Å, c = 16.8206(12) Å, alpha = 105.9050(10) degrees, beta = 95.8930(10) degrees, gamma = 111.0100(10) degrees, V = 1906.1(2) Å(3), Z = 2, and R = 0.0650 based on 5268 unique reflections. The FABMS+ in (p-nitrobenzyl alcohol) of 3 reveals a parent ion peak at m/z 799.2. The complex [Re(HNNpy)(NNpy)(PMe(2)Ph)(2)Cl](+)[Cl](-) (2) contains a chelated, neutral organodiazene ligand and a linear, diazenido(1-) ligand. The X-ray structural analysis of 2, C(26)H(30)Cl(2)N(6)P(2)Re, indicates a delocalized pi-system formed by the chelate ring. The (1)H NMR spectrum of 2 is not paramagnetically shifted. Complex 2 crystallizes in the orthorhombic space group Pna2(1) with a = 17.383(4) Å, b = 13.967(3) Å, c = 12.002(2) Å, V = 2913.9(10) Å(3), Z = 4, and R = 0.0384 based on 3083 unique reflections.

This article explores Orem's self-care model in relation to the care of a dying person and his/her family and gives an overview of the model together with illustrations of key concepts. The main recommendation of the article is that Orem's model should be viewed within the context of existential humanism. It concludes with the view that the model should be linked to the concept of clinical supervision.

Clinical supervision and its influence on practice is of profound importance to nursing, midwifery and health visiting. This paper examines the role of clinical supervision in context and provides a case study illustration of fundamental concepts. A psychodynamic perspective is assumed for the discussion. The case for clinical supervision as a means to ensure the safe and effective delivery of health care is presented.