Structural determination of arginine-linked cisplatin complexes via IRMPD action spectroscopy: arginine binds to platinum via NO- binding mode.

Cisplatin, (NH3)2PtCl2, has been known as a successful metal-based anticancer drug for more than half a century. Its analogue, Argplatin, arginine-linked cisplatin, (Arg)PtCl2, is being investigated because it exhibits reactivity towards DNA and RNA that differs from that of cisplatin. In order to understand the basis for its altered reactivity, the deprotonated and sodium cationized forms of Argplatin, [(Arg-H)PtCl2]- and [(Arg)PtCl2 + Na]+, are examined by infrared multiple photon dissociation (IRMPD) action spectroscopy in the IR fingerprint and hydrogen-stretching regions. Complementary electronic structure calculations are performed using density functional theory approaches to characterize the stable structures of these complexes and to predict their infrared spectra. Comparison of the theoretical IR spectra predicted for various stable conformations of these Argplatin complexes to their measured IRMPD spectra enables determination of the binding mode(s) of Arg to the Pt metal center to be identified. Arginine is found to bind to Pt in a bidentate fashion to the backbone amino nitrogen and carboxylate oxygen atoms in both the [(Arg-H)PtCl2]- and [(Arg)PtCl2 + Na]+ complexes, the NO- binding mode. The neutral side chain of Arg also interacts with the Pt center to achieve additional stabilization in the [(Arg-H)PtCl2]- complex. In contrast, Na+ binds to both chlorido ligands in the [(Arg)PtCl2 + Na]+ complex and the protonated side chain of Arg is stabilized via hydrogen-bonding interactions with the carboxylate moiety. These findings are consistent with condensed-phase results, indicating that the NO- binding mode of arginine to Pt is preserved in the electrospray ionization process even under variable pH and ionic strength.

Fatigue and depression predict reduced health-related quality of life in childhood-onset lupus.

We aimed to identify risk factors for persistently reduced health-related quality of life in childhood-onset lupus and describe a risk profile for persistently reduced health-related quality of life. At a tertiary rheumatology clinic, 50 childhood onset lupus patients were assessed twice, approximately six months apart. Measures of disease activity and patient-reported measures of health-related quality of life, pain, depressive symptoms, anxiety and disability were collected at each visit. At visits 1 and 2, respectively, clinically relevant fatigue was present in 66% and 56% of patients; clinically significant depressive symptoms in 26% and 24%; and clinically significant anxiety in 34% and 28%. Poorer health-related quality of life at follow-up was significantly predicted by higher fatigue and depressive symptoms at the initial visit. Using clinically relevant cut-offs for fatigue and depressive symptoms, patients were assigned to Low ( n = 27) or High Risk ( n = 23) groups. A profile of significantly greater pain, anxiety and coping difficulties was seen in the High Risk group. Routine assessment of fatigue and mood symptoms in youth with childhood-onset lupus could be helpful in identifying those at risk for persistently poor health-related quality of life. Integration of behavioral interventions to address fatigue and mood symptoms into medical care for such patients may be beneficial, but more research in this area is needed.

Effects of sodium cationization versus protonation on the conformations and N-glycosidic bond stabilities of sodium cationized Urd and dUrd: solution conformation of [Urd+Na]+ is preserved upon ESI.

Uridine (Urd) is one of the naturally occurring pyrimidine nucleosides of RNA. 2'-Deoxyuridine (dUrd) is a naturally occurring modified form of Urd, but is not one of the canonical DNA nucleosides. In order to understand the effects of sodium cationization on the conformations and energetics of Urd and dUrd, infrared multiple photon dissociation (IRMPD) action spectroscopy experiments and density functional theory (DFT) calculations are performed. By comparing the calculated IR spectra of [Urd+Na]+ and [dUrd+Na]+ with the measured IRMPD spectra, the stable low-energy conformers populated in the experiments are determined. Anti oriented bidentate O2 and O2' binding conformers of [Urd+Na]+ are the dominant conformers populated in the experiments, whereas syn oriented tridentate O2, O4', and O5' binding conformers of [dUrd+Na]+ are dominantly populated in the experiments. The 2'-hydroxyl substituent of Urd stabilizes the anti oriented O2 binding conformers of [Urd+Na]+. Significant differences between the measured IRMPD and calculated IR spectra for complexes of [Urd+Na]+ and [dUrd+Na]+ involving minor tautomeric forms of the nucleobase make it obvious that none are populated in the experiments. Survival yield analyses based on energy-resolved collision-induced dissociation (ER-CID) experiments suggest that the relative stabilities of protonated and sodium cationized Urd and dUrd follow the order: [dUrd+H]+ < [Urd+H]+ < [dUrd+Na]+ < [Urd+Na]+. The 2'-deoxy modification is found to weaken the glycosidic bond of dUrd versus that of Urd for the sodium cationized uridine nucleosides.

Acute stroke unit improves stroke management-four years on from INASC.

The Irish Heart Foundation carried out the Irish National Audit of Stroke Care (INASC) in 2008. Management practices were significantly poorer than those in the UK Sentinel audits. Since then an acute stroke unit has been established in University Hospital Limerick. A stroke database was established. 12 key indicators of stroke management audited by INASC were identified. Results were compared to those in INASC. 89 stroke patients were admitted. 8 of the 12 key indicators scored significantly better than in INASC. 92.5% had a brain scan within 24hrs (INASC-40%, p = < 0.001). 100% of ischaemic strokes received anti-thrombotics (INASC-85%, p = 0.001). 94% had rehab goals agreed by MDT (22% in INASC p = 0.0000). 55% were treated in stroke unit (2% in INASC, p = 0.0000). MDT input improved with regard to physiotherapy (87% vs 43% in INASC, p = < 0.02) and SALT (74% vs 26%, p = < 0.02). Stroke management has significantly improved from 2008, however some deficiencies remain.

MeV-energy x rays from inverse compton scattering with laser-wakefield accelerated electrons.

We report the generation of MeV x rays using an undulator and accelerator that are both driven by the same 100-terawatt laser system. The laser pulse driving the accelerator and the scattering laser pulse are independently optimized to generate a high energy electron beam (>200 MeV) and maximize the output x-ray brightness. The total x-ray photon number was measured to be ∼1×10(7), the source size was 5 µm, and the beam divergence angle was ∼10 mrad. The x-ray photon energy, peaked at 1 MeV (reaching up to 4 MeV), exceeds the thresholds of fundamental nuclear processes (e.g., pair production and photodisintegration).

Structural Determination of Lysine-Linked Cisplatin Complexes via IRMPD Action Spectroscopy: NNs and NO- Binding Modes of Lysine to Platinum Coexist.

Despite its success as an anticancer drug, cisplatin suffers from resistance and produces side effects. To overcome these limitations, amino-acid-linked cisplatin analogues have been investigated. Lysine-linked cisplatin, Lysplatin, (Lys)PtCl2, exhibited outstanding reactivity toward DNA and RNA that differs from that of cisplatin. To gain insight into its differing reactivity, the structure of Lysplatin is examined here using infrared multiple photon dissociation (IRMPD) action spectroscopy. To probe the influence of the local chemical environment on structure, the deprotonated and sodium-cationized Lysplatin complexes are examined. Electronic structure calculations are performed to explore possible modes of binding of Lys to Pt, their relative stabilities, and to predict their infrared spectra. Comparisons of the measured IRMPD and predicted IR spectra elucidate the structures contributing to the experimental spectra. Coexistence of two modes of binding of Lys to Pt is found where Lys binds via the backbone and side-chain amino nitrogen atoms, NNs, or to the backbone amino and carboxylate oxygen atoms, NO-. Glycine-linked cisplatin and arginine-linked cisplatin complexes have previously been found to bind only via the NO- binding mode. Present results suggest that the NNs binding conformers may be key to the outstanding reactivity of Lysplatin toward DNA and RNA.

Impact of the 2'- and 3'-Sugar Hydroxyl Moieties on Gas-Phase Nucleoside Structure.

Modified nucleosides have been an important target for pharmaceutical development for the treatment of cancer, herpes simplex virus, and the human immunodeficiency virus (HIV). Amongst these nucleoside analogues, those based on 2',3'-dideoxyribose sugars are quite common, particularly in anti-HIV applications. The gas-phase structures of several protonated 2',3'-dideoxyribose nucleosides are examined in this work and compared with those of the analogous protonated DNA, RNA, and arabinose nucleosides to elucidate the influence of the 2'- and combined 2',3'-hydroxyl groups on intrinsic structure. Infrared multiple photon dissociation (IRMPD) action spectra are collected for the protonated 2',3'-dideoxy forms of adenosine, guanosine, cytidine, thymidine and uridine, [ddAdo+H]+, [ddGuo+H]+, [ddCyd+H]+, [ddThd+H]+, and [ddUrd+H]+, in the IR fingerprint and hydrogen-stretching regions. Molecular mechanics conformational searching followed by electronic structure calculations generates low-energy conformers of the protonated 2',3'-dideoxynucleosides and corresponding predicted linear IR spectra to facilitate interpretation of the measured IRMPD action spectra. These experimental IRMPD spectra and theoretical calculations indicate that the absence of the 2'- and 3'-hydroxyls largely preserves the protonation preferences of the canonical forms. The spectra and calculated structures indicate a slight preference for C3'-endo sugar puckering. The presence of the 3'- and further 2'-hydroxyl increases the available intramolecular hydrogen-bonding opportunities and shifts the sugar puckering modes for all nucleosides but the guanosine analogues to a slight preference for C2'-endo over C3'-endo. Graphical Abstract.

Structures and Relative Glycosidic Bond Stabilities of Protonated 2'-Fluoro-Substituted Purine Nucleosides.

The 2'-substituent is the primary distinguishing feature between DNA and RNA nucleosides. Modifications to this critical position, both naturally occurring and synthetic, can produce biologically valuable nucleoside analogues. The unique properties of fluorine make it particularly interesting and medically useful as a synthetic nucleoside modification. In this work, the effects of 2'-fluoro modification on the protonated gas-phase purine nucleosides are examined using complementary tandem mass spectrometry and computational methods. Direct comparisons are made with previous studies on related nucleosides. Infrared multiple photon dissociation action spectroscopy performed in both the fingerprint and hydrogen-stretching regions allows for the determination of the experimentally populated conformations. The populated conformers of protonated 2'-fluoro-2'-deoxyadenosine, [Adofl+H]+, and 2'-fluoro-2'-deoxyguanosine, [Guofl+H]+, are highly parallel to their respective canonical DNA and RNA counterparts. Both N3 and N1 protonation sites are accessed by [Adofl+H]+, stabilizing syn and anti nucleobase orientations, respectively. N7 protonation and anti nucleobase orientation dominates in [Guofl+H]+. Spectroscopically observable intramolecular hydrogen-bonding interactions with fluorine allow more definitive sugar puckering determinations than possible for the canonical systems. [Adofl+H]+ adopts C2'-endo sugar puckering, whereas [Guofl+H]+ adopts both C2'-endo and C3'-endo sugar puckering. Energy-resolved collision-induced dissociation experiments with survival yield analyses provide relative glycosidic bond stabilities. The N-glycosidic bond stabilities of the protonated 2'-fluoro-substituted purine nucleosides are found to exceed those of their canonical analogues. Further, the N-glycosidic bond stability is found to increase with increasing electronegativity of the 2'-substituent, i.e., H < OH < F. The N-glycosidic bond stability is also greater for the adenine nucleoside analogues than the guanine nucleoside analogues.

In light of recently published clinical trials and their implication for clinical practice, does a large catchment area acute hospital require 24 hour CT neck and head angiography and/or neuro-interventional services in the setting of acute ischaemic stroke?

BACKGROUND: Recently published clinical trials have resulted in a significant change in the guidelines used to manage patients suffering an acute ischaemic stroke. New neuro-interventional techniques have revolutionised stroke outcomes. Currently, such services are only available in two specialist centres. AIMS: We attempted to evaluate the need for the provision of routine computed tomography (CT) angiography and neuro-interventional services at a university teaching hospital in Limerick. METHODS: A retrospective study was performed based on data collated by the stroke service, University Hospital Limerick (UHL). All patients with a suspected acute ischaemic stroke of anterior circulation and known evolution were included. Baseline clinical and imaging characteristics, thrombolysis data, stroke unit admission rates and discharge destinations were recorded. RESULTS: All 141 patients were suitable for CT angiography and should be performed in accordance with guidelines. Additionally, 165 patients excluded from the study due to an unknown stroke evolution timeframe may have benefitted. Non-contrast CT scan confirmed just 12 anterior circulation strokes. The need for neuro-interventional services proved more difficult to assess, primarily due to the lack of provision of routine CT angiography, employed to confirm anterior circulation occlusion. Secondary results showed a thrombolysis rate of 10.8% and confirmed that time efficiencies result in higher thrombolysis eligibility rates. Stroke unit admissions and discharge destinations were also recorded. CONCLUSION: UHL should provide routine CT angiography to all patients presenting with acute ischaemic stroke in line with current guidelines. The need for provision of neuro-interventional services on-site proved more difficult to assess and requires further analysis.

Modified Quadrupole Ion Trap Mass Spectrometer for Infrared Ion Spectroscopy: Application to Protonated Thiated Uridines.

Modifications to a Paul-type quadrupole ion trap mass spectrometer providing optical access to the trapped ion cloud as well as hardware and software for coupling to a table-top IR optical parametric oscillator laser (OPO) are detailed. Critical experimental parameters for infrared multiple photon dissociation (IRMPD) on this instrument are characterized. IRMPD action spectra, collected in the hydrogen-stretching region with this instrument, complemented by spectra in the IR fingerprint region acquired at the FELIX facility, are employed to characterize the structures of the protonated forms of 2-thiouridine, [s2Urd+H]+, and 4-thiouridine, [s4Urd+H]+. The measured spectra are compared with predicted linear IR spectra calculated at the B3LYP/6-311+G(d,p) level of theory to determine the conformers populated in the experiments. This comparison indicates that thiation at the 2- or 4-positions shifts the protonation preference between the 2,4-H tautomer and 4-protonation in opposite directions versus canonical uridine, which displays a roughly equal preference for the 2,4-H tautomer and O4 protonation. As found for canonical uridine, protonation leads to a mixture of conformers exhibiting C2'-endo and C3'-endo sugar puckering with an anti nucleobase orientation being populated for both 2- and 4-thiated uridine. Graphical Abstract ᅟ.

IRMPD Action Spectroscopy, ER-CID Experiments, and Theoretical Studies of Sodium Cationized Thymidine and 5-Methyluridine: Kinetic Trapping During the ESI Desolvation Process Preserves the Solution Structure of [Thd+Na].

Thymidine (dThd) is a fundamental building block of DNA nucleic acids, whereas 5-methyluridine (Thd) is a common modified nucleoside found in tRNA. In order to determine the conformations of the sodium cationized thymine nucleosides [dThd+Na]+ and [Thd+Na]+ produced by electrospray ionization, their infrared multiple photon dissociation (IRMPD) action spectra are measured. Complementary electronic structure calculations are performed to determine the stable low-energy conformations of these complexes. Geometry optimizations and frequency analyses are performed at the B3LYP/6-311+G(d,p) level of theory, whereas energies are calculated at the B3LYP/6-311+G(2d,2p) level of theory. As protonation preferentially stabilizes minor tautomers of dThd and Thd, tautomerization facilitated by Na+ binding is also considered. Comparisons of the measured IRMPD and computed IR spectra find that [dThd+Na]+ prefers tridentate (O2,O4',O5') coordination to the canonical 2,4-diketo form of dThd with thymine in a syn orientation. In contrast, [Thd+Na]+ prefers bidentate (O2,O2') coordination to the canonical 2,4-diketo tautomer of Thd with thymine in an anti orientation. Although 2,4-dihydroxy tautomers and O2 protonated thymine nucleosides coexist in the gas phase, no evidence for minor tautomers is observed for the sodium cationized species. Consistent with experimental observations, the computational results confirm that the sodium cationized thymine nucleosides exhibit a strong preference for the canonical form of the thymine nucleobase. Survival yield analyses based on energy-resolved collision-induced dissociation (ER-CID) experiments suggest that the relative stabilities of protonated and sodium cationized dThd and Thd follow the order [dThd+H]+ < [Thd+H]+ < [dThd+Na]+ < [Thd+Na]+. Graphical Abstract ᅟ.

Influence of Transition Metal Cationization versus Sodium Cationization and Protonation on the Gas-Phase Tautomeric Conformations and Stability of Uracil: Application to [Ura+Cu]+ and [Ura+Ag].

The gas-phase conformations of transition metal cation-uracil complexes, [Ura+Cu]+ and [Ura+Ag]+, were examined via infrared multiple photon dissociation (IRMPD) action spectroscopy and theoretical calculations. IRMPD action spectra were measured over the IR fingerprint and hydrogen-stretching regions. Structures and linear IR spectra of the stable tautomeric conformations of these complexes were initially determined at the B3LYP/6-31G(d) level. The four most stable structures computed were also examined at the B3LYP/def2-TZVPPD level to improve the accuracy of the predicted IR spectra. Two very favorable modes of binding are found for [Ura+Cu]+ and [Ura+Ag]+ that involve O2N3 bidentate binding to the 2-keto-4-hydroxy minor tautomer and O4 monodentate binding to the canonical 2,4-diketo tautomer of Ura. Comparisons between the measured IRMPD and calculated IR spectra enable elucidation of the conformers present in the experiments. These comparisons indicate that both favorable binding modes are represented in the experimental tautomeric conformations of [Ura+Cu]+ and [Ura+Ag]+. B3LYP suggests that Cu+ exhibits a slight preference for O4 binding, whereas Ag+ exhibits a slight preference for O2N3 binding. In contrast, MP2 suggests that both Cu+ and Ag+ exhibit a more significant preference for O2N3 binding. The relative band intensities suggest that O4 binding conformers comprise a larger portion of the population for [Ura+Ag]+ than [Ura+Cu]+. The dissociation behavior and relative stabilities of the [Ura+M]+ complexes, M+ = Cu+, Ag+, H+, and Na+) are examined via energy-resolved collision-induced dissociation experiments. The IRMPD spectra, dissociation behaviors, and binding preferences of Cu+ and Ag+ are compared with previous and present results for those of H+ and Na+. Graphical Abstract ᅟ.

The renal mitochondrial metabolism of 25-hydroxyvitamin D-3: a possible role for phospholipids.

The effect of exogenous phospholipids on chick kidney mitochondrial 25-hydroxyvitamin D-3 metabolism was examined. Phosphatidylserine, phosphatidylcholine and phosphatidylinositol had no effect on either the 1- or 24-hydroxylation of 25-hydroxyvitamin D-3. Phosphatidylethanolamine and cardiolipin both brought about a dose-dependent decrease in the 1-hydroxylase activity in mitochondria from vitamin D-deficient chicks but not from vitamin D-replete chicks. There were no major differences in the phospholipid composition of mitochondria from vitamin D-deficient and -replete chicks nor in the fatty acid composition of these phospholipids. Preliminary kinetic studies suggest that cardiolipin acts as a noncompetitive inhibitor of the 1-hydroxylase in mitochondria isolated from vitamin D-deficient chicks. It does not appear to exert its effect by virtue of altering the distribution of substrate or products. Investigation of the effect of fatty acid methyl esters on the hydroxylase activities suggests that it may be the fatty acid moiety of the phospholipid, rather than the phosphate moiety in the polar head group, that is involved in the phospholipid effect on the hydroxylation of 25-hydroxyvitamin D-3.

Bone-inducing activity of mature BMP-2b produced from a hybrid BMP-2a/2b precursor.

The human osteoinductive proteins BMP-2a and BMP-2b have been cloned and expressed in mammalian cells. In order to improve expression levels we examined the role of the proregion in assembly and export. Use of the BMP-2a proregion combined with the mature region of BMP-2b leads to dramatically improved expression of mature BMP-2b. Mature BMP-2b has been purified to near homogeneity from the BMP-2a/2b hybrid, and its structural properties and biological activity determined. Recombinant mature BMP-2b homodimer elicits bone formation in vivo.

Initiation and promotion of bone differentiation by bone morphogenetic proteins.

The presence of growth and differentiation factors in bone has been demonstrated by subcutaneous implantation of demineralized bone matrix that initiates new cartilage and bone morphogenesis. The genes for bone morphogenetic proteins (BMPs) have been cloned and expressed. Recombinant BMPs induce endochondral bone formation in vivo. The multistep sequential developmental cascade consists of chemotaxis, mitosis, and differentiation of cartilage and bone. The pleiotropic response has been well characterized. BMPs stimulate osteogenic and chondrogenic phenotypes. Natural bovine osteogenin (BMP-3) and recombinant BMP-4 are equipotent in chemotaxis, limb bud chondrogenesis, cartilage maintenance, and in vivo bone induction. There are multiple isoforms of BMPs, raising the biologic relevance of the redundancy. The mode of action and second messengers are not clear. BMPs appear to have cognate receptors as demonstrated by iodinated BMP-2B (BMP-4). Other novel members of the BMP family include osteogenic protein 1 (BMP-7) and osteogenic protein 2 (BMP-8). Bone morphogenetic proteins are members of the transforming growth factor-beta superfamily and include three distinct subfamilies: BMP-2, BMP-3, and BMP-7. Native BMP-3 and recombinant BMP-4 bind type IV collagen of the basement membrane. This novel connection may be the long elusive mechanistic explanation for the requirement of angiogenesis and vascular invasion for bone morphogenesis. BMPs may have a role in fracture repair, periodontal regeneration, and alveolar ridge augmentation.

Homologous desensitization of cultured chick kidney cells to parathyroid hormone.

The development of refractoriness of the cAMP response to PTH in primary cultures of chick kidney cells and recovery from the refractory state was investigated. When cells were preincubated with bovine PTH1-34, complete refractoriness to a subsequent challenge with the hormone developed within 2 h and at hormone concentrations as low as 5 ng/ml. The ability of PTH to stimulate activation of cAMP-dependent protein kinase was also abolished by preincubation with the hormone. When cells were desensitized and then incubated in hormone-free medium, recovery of the cAMP response began within an hour and was maximal, but not complete (80%) after 16 h. Cycloheximide did not affect either desensitization or the rate or extent of recovery from the refractory state. Low concentrations of forskolin (2.5 X 10(-7) M) greatly enhanced cAMP production stimulated by PTH and higher concentrations (10(-6) - 10(-4) M) stimulated rates of cAMP production 50 times those obtained with PTH alone. Preincubation with forskolin did not bring about desensitization to PTH nor did preincubation with PTH affect the subsequent response to forskolin. The half-life of biologically active bovine PTH1-34 in chick kidney cell culture was approximately 12 h and the rate of its removal was not significantly altered during a 20-h incubation period. The results suggest that desensitization of chick kidney cells to PTH is not suggest that desensitization of chick kidney cells to PTH is not brought about by cAMP generation itself, is not primarily dependent on protein synthesis, and does not involve a change in the rate of removal of biologically active hormone from the medium. In addition, recovery of the cAMP response to PTH also does not require new protein synthesis. These results are compatible with a mechanism of desensitization which occurs at the level of the receptor or hormone-receptor coupling to adenyl cyclase.

The number of 1,25-dihydroxyvitamin D3 receptors is decreased in both intestine and kidney of genetically diabetic db/db mice.

In previous studies on calcium homeostasis in diabetes, drug-induced diabetic rats have generally been used, and various alterations have been demonstrated in several parameters of the vitamin D-endocrine system. It is, however, still questionable whether the drug-induced diabetic rat is the most appropriate animal model for the investigation of calcium and vitamin D metabolism because of the toxicity of diabetogenic agents toward the principle organs of vitamin D metabolism, such as liver and kidney. Therefore, in the present study, we examined the strain of genetically diabetic mice, C57BL/KsJ db/db, to evaluate 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] receptors in intestine and kidney and to investigate the alterations of calcium and vitamin D metabolism. In both control and diabetic mice, intestinal and renal 1,25-(OH)2D3 receptors were demonstrated; they had a sedimentation coefficient of 3.4S. The number of specific 1,25-(OH)2D3-binding sites in intestine was 118 +/- 11 fmol/mg protein in diabetic mice, significantly lower than the value of 199 +/- 11 fmol/mg protein in controls (P less than 0.01). Moreover, the renal concentration of specific 1,25-(OH)2D3-binding sites of 34.6 +/- 7.1 fmol/mg protein in diabetic mice was also significantly reduced compared to the value of 63.3 +/- 5.7 fmol/mg protein in controls (P less than 0.01). There were no significant differences in the equilibrium dissociation constants (Kd) of intestinal and renal receptors between control and diabetic mice. Significant hypocalcemia was demonstrated in the diabetic mice (P less than 0.01), suggesting the development of a negative calcium balance. Diabetic mice showed a significant decrease in renal 24,25-(OH)2D3 production (P less than 0.02), whereas renal 1,25-(OH)2D3 production was significantly increased in the diabetic group (P less than 0.05) compared to the control value. It is probable from these results that the genetic/endogenous diabetes may be directly associated with the alterations of mineral homeostasis. The altered calcium and vitamin D metabolism in diabetic mice is suggested to be derived, at least in part, from the decreased number of the 1,25-(OH)2D3 receptors in both intestine and kidney in the diabetic state.

Estimation of melatonin in bovine plasma: patterns in Jersey heifers treated with cloprostenol at two times of day.

The estimation of melatonin in bovine plasma by radioimmunoassay is described and some aspects of specificity are discussed. Mean values for individual heifers ranged from 0.025 to 0.25 nmol/l during the day and were significantly (P less than 0.01) raised in each animal to mean values of 0.19 to 1.41 nmol/l at night. The hormonal changes after cloprostenol injections were not affected by the time of day at which the heifers were treated.

Selective termination of multiple gestations.

Twenty-two selective terminations in multiple gestations were performed by a number of different methods. In 17 dichorionic pregnancies there was a successful delivery in surviving singletons or twins. In five monochorionic pregnancies undergoing selective termination there was a successful delivery in only one and a pregnancy loss in the other four. Six of the 18 delivered pregnancies were complicated by premature labor and delivery. Among the several methods used for selective termination, intracardiac potassium chloride injection appears to be the procedure of choice in dichorionic pregnancies.

PIP: Physicians selectively terminated 22 fetuses of multiple gestations between November 1983-August 1987. In the case of same sex twins, after initially identifying 1 fetus by amniocentesis as chromosomally abnormal, fetal blood samples were drawn for karyotyping 48-72 hours before selective termination to identify the affected fetus. These samples were repeated at time of termination to confirm termination of that fetus. Practitioners used ultrasound to perform all procedures, except hysterotomy, and to confirm asystole in the affected fetus and normal heart activity in the remaining fetus (es). 18 patients delivered normal infants, 6 of whom delivered at a gestational age of 37 weeks. Only 1 infant of the 5 monochorionic pregnancies lived. In this case, termination of the sibling fetus occurred via hysterotomy and the physician prescribed oral tocolytics for the mother. Procedures used and their results for dichorionic pregnancies follow. Potassium chloride injections into the heart or into the pericardial region of the chest resulted in a reduced premature labor rate (20%) than did cardiac puncture with air embolization (33.3%). This may be due to decreased intrauterine manipulation and decreased procedure time required to administer the potassium chloride injections. 1 exsanguination was to be performed, but the affected fetus died in the interim between fetal blood sampling and the scheduled day of confirmation. As this study confirmed, poor outcome of remaining normal fetuses is based on premature labor and monochorionic placentation. New techniques add to the many social and ethical considerations of selective termination, especially in those cases where the aborted fetuses are normal.

Bone induction by osteogenin and bone morphogenetic proteins.

Bone induction is a multistep process that includes chemotaxis and attachment of mesenchymal stem cells, proliferation of progenitor cells and differentiation into cartilage and bone. Endochondral bone formation is the predominant sequence. Bone induction can be operationally divided into the following phases: initiation, promotion and maintenance. The initiation of bone induction is primarily regulated by osteogenin and bone morphogenetic proteins. Recent work has led to the isolation, purification and cloning of osteogenin and other bone morphogenetic proteins. Other growth factors such as platelet derived growth factor (PDGF), transforming growth factor beta (TGF-beta isoforms, insulin like growth factors (IGF 1 and 2), and fibroblast growth factor (FGF) may promote and perhaps maintain the newly induced bone.