Can transcription factors in the intervertebral disc of lopinavir/ritonavir prevent degeneration in the nucleus pulposus by mediating the regulation of inflammation through signaling pathways?

OBJECTIVE

This study was conducted to examine whether lopinavir/ritonavir (Lop/r), an HIV protease inhibitor, can improve disc physiology and slow down intervertebral disc (IVD) degeneration through in vitro experimental methods, as well as whether it can suppress inflammation with interleukin-1 beta (IL-1β) and sex-determining region Y (SRY) protein-related high-mobility group box genes-9 (SOX9) through hypoxia-inducible factor 1-alpha (HIF-1α) and the nuclear factor kappa B (NF-κB) signaling pathway. The aim was to investigate whether Lop/r application is toxic to IVD cells and the microenvironment simultaneously.

PATIENTS AND METHODS

Human primary cell cultures were prepared using herniated IVD tissues obtained from patients with lumbar disc hernia who were unresponsive to conservative and medical treatment, and thereby, were operated on. The untreated culture samples served as control group, and the samples treated with Lop/r served as study group. Microscopic evaluations were performed simultaneously using fluorescent and supravital dyes in all groups. In addition to cell viability, toxicity, and proliferation analysis through a commercial kit, IL-1β, SOX9, HIF-1α, and NF-κB protein expressions were evaluated using Western blotting. In the statistical comparison of the obtained data, an alpha value less than 0.05 was considered significant.

RESULTS

Cell proliferation decreased in the Lop/r group, but no cell death was observed (p < 0.05). Moreover, at the end of 72 hours after Lop/r application, IL-1β and NF-kB protein expressions decreased by 40% and 52%, respectively, while HIF-1α and SOX9 protein expressions increased by 4% and 59%, respectively (p< 0.05).

CONCLUSIONS

Although these data were obtained from an in vitro experimental study, it is believed that these findings could make significant contributions to the pharmaco-regenerative treatment modalities of IVD degeneration. Lop/r suppresses the IL-1β and NF-κB and induces SOX9 and HIF-1α, since these signaling pathways may be related to human IVD degeneration.

Effects of an acetylcholinesterase inhibitor and an N-methyl-D-aspartate receptor antagonist on inflammation and degeneration of the nucleus pulposus

OBJECTIVE

The study aimed to examine the effects of two drugs, an acetylcholinesterase inhibitor (AChEI) and an N-methyl-D-aspartate receptor (NMDAR) antagonist, on degenerated annulus fibrosus (AF) and nucleus pulposus (NP) cells and the extracellular matrix (ECM) structure in vitro.

PATIENTS AND METHODS

Tissue samples were obtained from patients with intervertebral disc herniation (four males and four females; classified as Pfirmann stage IV) and used to prepare cell cultures. Untreated cell culture samples served as the control group. Study group samples were treated with donepezil, memantine or a combination of the two drugs. Cell viability, toxicity and proliferation were evaluated in all groups. Western blotting was used to examine changes in protein expression of signal transducer and activator of transcription 3 (STAT3), phospho-STAT3 (ser727), hypoxia-inducible factor (HIF)-1 alpha (HIF-1α) and nucleotide-binding oligomerisation domain (NOD) leucine-rich repeat (LRR)-containing proteins (NLR) family pyrin domain containing 3 (NLRP3) inflammasome. The alpha significance value was < 0.05.

RESULTS

Analysis of the microscopy and commercial kit results revealed that cell proliferation was suppressed, and no cell death was observed. The protein expression levels of NLRP3, STAT3, ser727 and HIF-1α were lower in the samples treated with donepezil and memantine at 72 h (p < 0.05). The protein expression levels of NLRP3, STAT3, ser727 and HIF-1α were higher in the samples treated with the combination of donepezil and memantine (p < 0.05).

CONCLUSIONS

The combined administration of memantine a NMDAR antagonist which can prevent neurodegeneration and donepezil an AChEI used for pain relief increased the protein expression levels in the anabolic pathway. However, it did not reduce the protein expression levels in the catabolic pathway. Therefore, further studies are needed to provide extensive insight into whether it may be among the potential targets for the therapy of intervertebral disc (IVD) diseases.

LIPSS-based functional surfaces produced by multi-beam nanostructuring with 2601 beams and real-time thermal processes measurement

A unique combination of the ultrashort high-energy pulsed laser system with exceptional beam quality and a novel Diffractive Optical Element (DOE) enables simultaneous production of 2601 spots organized in the square-shaped 1 × 1 mm matrix in less than 0.01 ms. By adjusting the laser and processing parameters each spot can contain Laser Induced Periodic Surface Structures (LIPSS, ripples), including high-spatial frequency LIPSS (HFSL) and low-spatial frequency LIPSS (LSFL). DOE placed before galvanometric scanner allows easy integration and stitching of the pattern over larger areas. In addition, the LIPSS formation was monitored for the first time using fast infrared radiometry for verification of real-time quality control possibilities. During the LIPSS fabrication, solidification plateaus were observed after each laser pulse, which enables process control by monitoring heat accumulation or plateau length using a new signal derivation approach. Analysis of solidification plateaus after each laser pulse enabled dynamic calibration of the measurement. Heat accumulation temperatures from 200 to 1000 °C were observed from measurement and compared to the theoretical model. The temperature measurements revealed interesting changes in the physics of the laser ablation process. Moreover, the highest throughput on the area of 40 × 40 mm reached 1910 cm²/min, which is the highest demonstrated throughput of LIPSS nanostructuring, to the best of our knowledge. Thus, showing great potential for the efficient production of LIPSS-based functional surfaces which can be used to improve surface mechanical, biological or optical properties.

In-vitro activity of tigecycline against multidrug-resistant Gram negative bacteria: The experience of a university hospital

The emergence of multidrug-resistant Gram negative bacteria has given rise to significant therapeutic challenges. These pathogens may have developed resistance to tigecycline, which is an alternative antibiotic used empirically in the treatment of serious infections. The objectives of this study were to identify the in-vitro activity of tigecycline against multidrug-resistant Gram negative strains isolated from clinical specimens and their related genes, at a university hospital. For this, 150 clinical isolates of multidrug-resistant Gram negative cultures from various clinical specimens were collected. Bacterial isolates were cultured, identified and their antibiotic susceptibilities were determined. Polymerase chain reaction was performed to amplify AcrB, AmpC, RamR, MexR, AdeB, TetA genes. Results revealed that all isolates were multidrug-resistant. The resistance of isolates was 91.4% to aztreonam, 94.6% to piperacillin, 34% to imipenem, 38.7% to meropenem, 71.3% to levofloxacin, 97.3% to ceftriaxone, 94.7% to cefepime, 9.3% to colistin, 78% to tetracycline, 21.4% to tigecycline and 68% to trimethoprim. AcrB, AmpC, RamR, MexR, AdeB, TetA genes were present in multidrug-resistant Gram negative bacteria. AcrB, RamR, TetA genes were related to tigecycline resistance. It is concluded that infections caused by multidrug-resistant Gram negative bacteria occur at a high rate. Most isolates were multi drug resistant, with 21.4% being resistant to tigecycline.

A-63 The Fatigue Severity Scale and Depression in an Aging Population

Objective

The Fatigue Severity Scale (FSS) is often used in clinical populations in which fatigue is a common symptom (e.g., multiple sclerosis). Despite the prevalence of fatigue in depression, relatively few investigations have examined the relationship between the FSS and mood symptoms, particularly in aging populations with concerns of memory loss. Thus, the primary aim of the present investigation was to elucidate the relationship between fatigue symptoms and depression among older adults evaluated in a cognitive disorders clinic.

Method

Data were collected as part of a neuropsychological battery administered to patients presenting to clinic due to complaints of memory impairment. Scores on the FSS and the Geriatric Depression Scale (GDS) were collected from 430 patients (48.10% women). Mean age was 74.97 years (SD = 5.81) and 147 subjects were diagnosed with depression, based on a score of 10 or above on the GDS.

Results

We observed a small, but significant inverse relationship between age and scores on the FSS [r = -.103, p = .033], such that older adults endorsed less severe fatigue. A moderate, positive relationship between FSS and GDS was observed [r = .416, p = .000]. Comparing FSS endorsement between depressed and non-depressed individuals finds individuals with depression endorsed significantly greater levels of fatigue than non-depressed individuals, even after accounting for the effects of age [F(1, 427) = 85.79. p < .001; Cohen's d = 0.96].

Conclusion

Present findings suggest that older adults do not necessarily endorse higher rates of fatigue on the FSS. However, the presence of depression in older adults has large effects on fatigue severity.

Limit theorems for a branching process with disasters

A Bellman–Harris process is considered where the population is subjected to disasters which occur at random times. Each particle alive at the time of a disaster survives it with probability p. In the situation when explosion can occur, several limit theorems are proven. In particular, we prove that the age-distribution converges to the same stable distribution as the Bellman-Harris process and that the population size continues to be asymptotically exponential.

Oncogenic RIT1 mutations in lung adenocarcinoma

Lung adenocarcinoma is comprised of distinct mutational subtypes characterized by mutually exclusive oncogenic mutations in RTK/RAS pathway members KRAS, EGFR, BRAF and ERBB2, and translocations involving ALK, RET and ROS1. Identification of these oncogenic events has transformed the treatment of lung adenocarcinoma via application of therapies targeted toward specific genetic lesions in stratified patient populations. However, such mutations have been reported in only ∼55% of lung adenocarcinoma cases in the United States, suggesting other mechanisms of malignancy are involved in the remaining cases. Here we report somatic mutations in the small GTPase gene RIT1 in ∼2% of lung adenocarcinoma cases that cluster in a hotspot near the switch II domain of the protein. RIT1 switch II domain mutations are mutually exclusive with all other known lung adenocarcinoma driver mutations. Ectopic expression of mutated RIT1 induces cellular transformation in vitro and in vivo, which can be reversed by combined PI3K and MEK inhibition. These data identify RIT1 as a driver oncogene in a specific subset of lung adenocarcinomas and suggest PI3K and MEK inhibition as a potential therapeutic strategy in RIT1-mutated tumors.

The LRRK2 G2019S mutation is associated with Parkinson disease and concomitant non-skin cancers

OBJECTIVE

In view of the fact that cancer patterns in patients with Parkinson disease (PD) differ from the general population, we aimed to verify whether patients with PD with LRRK2 mutations have an increased risk for particular cancer types.

METHODS

In this cross-sectional study, eligible consenting Jewish patients with PD were genotyped for the predominant LRRK2 G2019S mutation. Oncologic data were obtained by personal interview and reviewing patients' files. Stepwise logistic regression was applied to model the probability of cancer occurrence in carriers vs noncarriers.

RESULTS

Overall, 79/490 (16.1%) genotyped patients carried the G2019S mutation. Seventy-seven (16%) were diagnosed with cancer; of those, 67 (14%) with a non-skin cancer. Eighteen (23%) carriers vs 49 (12%) noncarriers had a non-skin cancer (p = 0.01, odds ratio [OR] = 2.18, 95% confidence interval [CI] 1.19-3.99). A significant ethnicity effect was noted (p = 0.045, OR = 1.84, 95% CI 1.02-3.34). Among Ashkenazi patients, age and LRRK2 emerged as significant using stepwise logistic regression including age, gender, and LRRK2 status as explanatory variables. The OR for LRRK2 mutation carriers adjusted for age was 3.38 (95% CI 1.64-6.97, p = 0.0009).

CONCLUSIONS

Ashkenazi Jewish patients with PD who harbor the G2019S LRRK2 mutation are more likely to have a concomitant non-skin cancer than noncarriers.

Clinical evaluation of nitric oxide responses to anti-VEGF therapy with bevacizumab

14039

Background: Anti-vascular endothelial growth factor (anti-VEGF) therapy has been linked to hypertension (HTN) and arterial thrombo-embolic events that may involve changes in nitric oxide (NO) bioavailability. Methods: 25 patients (pts) with advanced cancer, normal renal function and blood pressure (BP), no increased risks for anti-VEGF toxicities, and not on medications known to confound biomarker studies (including anti-hypertensives) were treated with bevacizumab (BV) 15mg/kg d1, then 10mg/kg q2 week. Prior to biomarker assessment, all patients were placed on a calorie-, nitrate-, and salt-restricted diet for 72 hr. All measures were taken pre-treatment (preRx) and on day 28 of treatment (onRx). Dependant variables included; a) Brachial artery reactivity (BAR) following hyperemic flow stimulus (endothelium-dependent) and sub-lingual nitroglycerine (NTG; endothelium-independent); b) exhaled and plasma/urine total NO2/NO3 using chemiluminescence (Sievers 280NOA) with either KI or VCl3 in HCl as the reductants; c) blood pressure. Additionally, we measured multiple regulators of vascular tone and injury. Comparisons were analyzed using Spearman signed rank tests. Results: Of 25 pts (16 F, 9 M) treated, 21 patients were fully evaluable. Significant changes or strong trends were observed upon comparing preRx vs. onRx for BP (SBP +12.4, DBP +5.6, MAP +7.9 mm Hg), and flow-mediated BAR (-2.0%) with no changes in hyperemic flow/shear stimulus or smooth muscle function (BAR NTG), indicating a decrease in brachial artery endothelial responsiveness. Exhaled NO decreased (-0.8% d1vs d28 and -0.6% pre/post infusion day1). Measurement and data analysis of urinary/plasma NO2/NO3, as well as angiogenic markers, are almost complete and will be reported. Conclusions: After one month of treatment, BV increased BP and decreased endothelium- dependent BAR and exhaled NO, suggesting potentially broad, mechanism-based effects on NO bioavailability in patients.

[Table: see text]

Conduction-electron drift velocity measurement via electron spin resonance

In analogy with NMR, motion induced phase shift of pulsed ESR signals enables in principle the direct detection of electron drift velocity or electronic current, respectively. Overcoming the difficulties with additional magnetic field gradients induced by the current itself, we succeeded in demonstrating the detection of electron flow via ESR. Measuring the electron drift velocity in the organic conductor (fluoranthene)2PF6 the microscopic Ohmic law could be observed in a current range of more than +/-0.25 A.

Zebralike patterned organic conductor with periodic modulation of mobility and Peierls transition

We manipulated the defect concentration in a (fluoranthene)2PF6 crystal by proton irradiation through a periodic grid, resulting in a striped defect pattern. Spatially resolved pulsed X-band ESR analysis was used to quantify the resulting local defect concentrations, spin diffusion coefficients, and electron spin concentrations. The temperature dependence of the data proves that spin diffusion coefficient and Peierls transition can be tailored in a controlled way via the defect concentrations.

Diffusive diffraction of the local ESR pulse-gradient spin-echo signal in a restricted one-dimensional conductor

The diffusive motion of the conducting electrons in the one-dimensional organic conductor FA2PF6 (FA, Fluoranthene) is studied with the ESR pulse-gradient spin-echo (PGSE) signal combined with spatial density ESR imaging. A local measurement of the short restricted regions reveals diffraction patterns in the local PGSE data. A model calculation adapted to the local measurements provides a highly accurate quantitative description of the results. The appearance of these patterns provides information about the diffusive motion of the charge at the crystal boundaries.

Combined k-space q-space pulsed ESR imaging: mapping of restricted diffusion in (FA)(2)PF(6)

A (FA)(2)PF(6) crystal from the family of the quasi-one-dimensional organic conductors was selectively damaged by a beam of Helium ions with a slitted mask placed in the beam's trajectory. Pulsed ESR density weighted imaging of the damaged crystal revealed the appearance of regions where the ESR signal was absent. The one-dimensional motion of the charge carriers was thus restricted to the undamaged sections. The local charge carrier spin dynamics in these restricted areas was probed by combined k-space q-space pulsed ESR imaging. The local expected appearance of the restricted pulsed gradient spin echo (PGSE) "diffusive diffraction" effect is shown. The position of the diffraction minima is compatible with the density imaging results.

Prospects for association-based fine mapping of a susceptibility gene for a complex disease

The potential of association studies for fine-mapping loci with common disease susceptibility alleles for complex genetic diseases in outbred populations is unclear. For a battery of tightly linked anonymous genetic markers spanning a candidate region centered around a disease locus, simulation methods based on a coalescent process with mutation, recombination, and genetic drift were used to study the spatial distribution of markers with large noncentrality parameters in a case-control study design. Simulations with a disease allele at intermediate frequency, presumably representing an old mutation, tend to exhibit the largest noncentrality parameter values at markers near the disease locus. In contrast, simulations with a disease allele at low frequency, presumably representing a young mutation, often exhibit the largest noncentrality parameter values at markers scattered over the candidate region. In the former case, sample sizes or marker densities sufficient to detect association are likely to lead to useful localization, whereas, in the latter case, localization of the disease locus within the candidate region is much less likely, regardless of the sample size or density of the map. The simulations suggest that for a single marker analysis, the simple strategy of choosing the marker with smallest associated P value to begin a laboratory search for the disease locus performs adequately for a common disease allele.

Issues concerning association studies for fine mapping a susceptibility gene for a complex disease

The usefulness of association studies for fine mapping loci with common susceptibility alleles for complex genetic diseases in outbred populations is unclear. We investigate this issue for a battery of tightly linked anonymous genetic markers spanning a candidate region centered around a disease locus, and study the joint behavior of chi-square statistics used to discover and to localize the disease locus. We used simulation methods based on a coalescent process with mutation, recombination, and genetic drift to examine the spatial distribution of markers with large noncentrality parameters in a case-control study design. Simulations with a disease allele at intermediate frequency, presumably representing an old mutation, tend to exhibit the largest noncentrality parameter values at markers near the disease locus. In contrast, simulations with a disease allele at low frequency, presumably representing a young mutation, often exhibit the largest noncentrality parameter values at markers scattered over the candidate region. In the former cases, sample sizes or marker densities sufficient to detect association are likely to lead to useful localization, whereas, in the latter case, localization of the disease locus within the candidate region is much less likely, regardless of the sample size or density of the map. The effects of increasing sample size or marker density are also investigated. Based upon a single marker analysis, we find that a simple strategy of choosing the marker with the smallest associated P value to begin a laboratory search for the disease locus performs adequately for a common disease allele. We also investigated a strategy of pooling nearby sites to form multiple allele markers. Using multiple degree of freedom chi-square tests for two or three nearby sites, we found no clear advantage of this form of pooling over a single marker analysis. Genet. Epidemiol. 20:432-457, 2001. Published by Wiley-Liss, 2001.

Maximizing antihypertensive management in the elderly

The management of hypertension in the elderly is safer and more effective if we consider diurnal fluctuations in blood pressure, preexisting postural and postprandial hypotension, and coronary risk when setting therapeutic goals and selecting or adjusting antihypertensive medications. Lifestyle modifications should coincide with drug therapy in the management of elderly hypertensive patients. The author suggests a checklist of specific considerations when treating hypertension in the elderly.

Spatial mapping of mobility and density of the conduction electrons in (FA)2PF6

Novel implementation of the Fourier imaging technique on conduction electron spins in the one-dimensional organic conductors (FA)2PF6 (FA: fluoranthene) is reported. Two-dimensional spatial imaging of resolution 30 &mgr;m(2) is combined with the pulsed-gradient spin-echo technique, to derive maps revealing the local properties of the electron spin density and mobility. The maps generally show pronounced inhomogeneity of both density and mobility on the scale of approximately 30-300 &mgr;m. Highly mobile regions were identified to exist, and the mobility in these was quantitatively evaluated by a basic theoretical model of restricted diffusion.

Low-dose clonidine and neostigmine prolong the duration of intrathecal bupivacaine-fentanyl for labor analgesia

BACKGROUND

Intrathecal (IT) opioid and local anesthetic combinations are popular for labor analgesia because of rapid, effective pain relief, but the duration of analgesia is limited. This study was undertaken to determine whether the addition of clonidine and neostigmine to IT bupivacaine-fentanyl would increase the duration of analgesia without increasing side effects for patients in labor.

METHODS

Forty-five healthy parturients in active labor were randomized to receive a 2-ml IT dose of one of the following dextrose-containing solutions using the combined spinal-epidural technique: (1) bupivacaine 2.5 mg and fentanyl 25 microg (BF); (2) BF plus clonidine 30 microg (BFC); or (3) BFC plus neostigmine 10 microg (BFCN). Pain, sensory levels, motor block, side effects, maternal vital signs, and fetal heart rate were systematically assessed.

RESULTS

Patients administered BFCN had significantly longer analgesia (165+/-32 min) than those who received BF (90+/-21 min; P<0.001) or BFC (123+/-21 min; P<0.001). Pain scores, block characteristics, maternal vital signs, Apgar scores, maternal satisfaction, and side effects were similar among groups except for nausea, which was significantly greater in the BFCN group (P<0.05 as compared with BFC).

CONCLUSIONS

The addition of clonidine and neostigmine significantly increased the duration of analgesia from IT bupivacaine-fentanyl during labor, but neostigmine caused more nausea. Although serious side effects were not observed in this study, safety must be further addressed before the routine use of multiple IT drugs is advocated.

Three-dimensional pulsed ESR Fourier imaging

Three-dimensional pulsed ESR imaging was performed on a (FA)(2)PF(6) crystal using a three-dimensional Fourier imaging sequence. The best resolution achieved was of 20 microm(3). Comparison with images obtained using the filtered back-projection method shows the superiority of this method under the given conditions.

Low dose combinations in the treatment of hypertension: theory and practice

The recent evolution of drug therapy for hypertension has primarily focused on new agents but there has been a renewed interest in the use of low doses of diuretic in combination with other agents. Such low-dose diuretic combinations are rational and their use will almost certainly increase.

Multiple echoes, multiple quantum coherence, and the dipolar field: demonstrating the significance of higher order terms in the equilibrium density matrix

It is well known that dipolar field effects lead to multiple spin echoes in a simple two-RF pulse experiment (the MSE experiment). We show here that coherence transfer echoes (which identify the existence of multiple quantum coherences in liquid NMR) and multiple spin echoes have a common origin. Using density matrix theory we have calculated the phase and timing of multiple spin echoes from all quadrature phase combinations of RF pulses. We show for the MSE experiment that there is a one-to-one correspondence between the time domain echo order and the multiple quantum coherence order. The experimental confirmation of these phase predictions shows that multiple spin echoes provide independent evidence for the breakdown of the high temperature approximation as proposed by Warren et al. (Science 262, 2005 (1993)).

Sibling-based tests of linkage and association for quantitative traits

The transmission/disequilibrium test (TDT) developed by Spielman et al. can be a powerful family-based test of linkage and, in some cases, a test of association as well as linkage. It has recently been extended in several ways; these include allowance for implementation with quantitative traits, allowance for multiple alleles, and, in the case of dichotomous traits, allowance for testing in the absence of parental data. In this article, these three extensions are combined, and two procedures are developed that offer valid joint tests of linkage and (in the case of certain sibling configurations) association with quantitative traits, with use of data from siblings only, and that can accommodate biallelic or multiallelic loci. The first procedure uses a mixed-effects (i.e., random and fixed effects) analysis of variance in which sibship is the random factor, marker genotype is the fixed factor, and the continuous phenotype is the dependent variable. Covariates can easily be accommodated, and the procedure can be implemented in commonly available statistical software. The second procedure is a permutation-based procedure. Selected power studies are conducted to illustrate the relative power of each test under a variety of circumstances.

Radiofrequency power calibration for magnetic resonance imaging using signal phase as indicator

A novel radiofrequency (rf) power calibration method for the purpose of nuclear magnetic resonance excitations based on monitoring signal phase rather than signal amplitude is described theoretically and is demonstrated experimentally. This unique method enables the determination of rf power required for any desired tip angle in clinical magnetic resonance imaging procedures with an accuracy of 1-5%, essentially independent of motion, flow, slice variations, and/or T1 and T2 variations. The advantages of the new method are discussed and are compared with currently common, amplitude-based calibration techniques.

A new diffusion SSFP imaging technique

In this paper a new diffusion sensitive steady-state free precession (SSFP) pulse sequence with a reduced sensitivity to physiological brain motion is presented. The signal attenuation due to diffusion in this SSFP sequence is derived theoretically and confirmed experimentally with a phantom. It is shown that for brain tissue this signal attenuation is approximately independent of T1 and T2, but depends only on the pulse sequence used, i.e., the timing and the size of the RF and the gradient pulses. On this basis the diffusion constant can be calculated for any region in the image. Diffusion sensitive images of the brain obtained with our pulse sequence are presented and shown to be superior over an image obtained with a "conventional" diffusion sensitive SSFP sequence.

Protein tyrosine phosphorylation in smooth muscle: a potential coupling mechanism between receptor activation and intracellular calcium

This review addresses a rapidly growing body of evidence suggesting that enhanced protein tyrosine phosphorylation may be a previously unrecognized mechanism for coupling receptor activation of vascular smooth muscle cells to increases In the intracellular concentration of Ca2+ and contraction. The hypothesis proposes that activation of diverse types of receptors that are not tyrosine kinase promotes stimulation of a cytosolic tyrosine kinase. In turn, the activated kinase induces tyrosine phosphorylation of substrates that are linked to regulatory mechanisms for release of intracellular Ca2+ stored in the sarcoplasmic reticulum and to regulatory mechanisms for influx of extracellular Ca2+. Within this framework, we examine some relevant functional aspects of receptor and nonreceptor tyrosine kinases in different types of cells, the emerging relationships between tyrosine kinase activity and regulation of intracellular Ca2+. We review studies of nonreceptor tyrosine kinase activity in vascular smooth muscle cells suggesting that a physiologically relevant kinase may be the enzyme called pp60. Data that appear to link tyrosine phosphorylation to contraction of smooth muscle are examined, particularly with respect to results obtained with tyrosine kinase inhibitors and measures of changes in tyrosine phosphorylation. Next, we review studies with cultured vascular smooth muscle cells that point to potential coupling between receptor activation, enhanced tyrosine phosphorylation of substrates such as the GTPase activating protein for ras, and the gamma-1 isoform of phospholipase C, and mechanisms controlling Ca2+ influx and release. Emphasis is placed on examining the strengths and weaknesses of different experimental approaches. Lastly, a summary of the data is provided which calls attention to some major issues requiring resolution to permit acceptance or rejection of the underlying hypothesis, and we briefly address some of its possible pathophysiological implications.

The myocardium and brain SPECT findings in organophosphate poisoning

A case of organophosphate poisoning is presented by using Tc-99m HMPAO (hexamethyl propylenamine oxime) brain SPECT (single photon emission computer tomography) and Tc-99m Sestamibi myocardial SPECT findings in the acute recovery and delayed phases. On the 4th day, brain SPECT imaging showed the perfusion defects in the left parietal lobe of the brain. On the 5th day myocardium scintigraphy also revealed the anterolateral wall perfusion defect. The myocardial defect became more prominent but brain defect was smaller than before, on the 19th day of the therapy. Two months later, on the third examinations of the brain and myocardium, their imagings were both normal.

Coupling between [arginine8]-vasopressin-activated increases in protein tyrosine phosphorylation and cellular calcium in A7r5 aortic smooth muscle cells

Effects of genistein, a tyrosine kinase inhibitor, on increases in [Ca2+]i and protein tyrosine phosphorylation induced by 20 nM [arginine 8]vasopressin (AVP) were studied in A7r5 aortic smooth muscle cells. In fura-2-loaded cells, AVP induced a rapid (0.5-2 min) transient increase in [Ca2+]i that was followed by a smaller sustained increase in [Ca2+]i. In 66% of the cells, the transient response involved both influx of extracellular Ca2+ and release of intracellular Ca2+: influx accounted for 6% of the response, and release accounted for 40%. However, in 34% of the cells, the relative contribution of influx and release during the transient could not be assessed. In all cells, the smaller sustained response was entirely dependent on extracellular Ca2+. Genistein (148 microM) always blocked the transient and sustained components of the Ca2+ response showing that both influx and release were genistein-sensitive. Isobestic fluorescence analysis, in medium containing 0.5 mM Mn2+ in place of Ca2+, showed that the influx pathway was selective because it did not conduct Mn2+. It also confirmed that Ca2+ release was blocked by genistein. In contrast, 105 microM lavendustin A, a different tyrosine kinase inhibitor, suppressed the transient by only 30%. Another inhibitor, tyrphostin 47 (80 microM), did not alter the transient or sustained components of the Ca2+ response. No AVP-induced increases in tyrosine phosphorylation were detected unless special procedures were used. When cells were preincubated in 10 mM vanadate, a tyrosine phosphatase inhibitor, AVP induced a transient increase in tyrosine phosphorylation (5-60 s). The time course for AVP-induced phosphorylation was similar to that for increase in [Ca2+]i. Vanadate alone increased tyrosine phosphorylation and induced a slow small increase in [Ca2+]i that was dependent on extracellular Ca2+. Genistein blocked tyrosine phosphorylation induced by AVP and vanadate, and it blocked the increase in [Ca2+]i induced by vanadate alone. In contrast, lavendustin or tyrphostin unexpectedly enhanced tyrosine phosphorylation induced by vanadate alone and precluded assessment of AVP-induced tyrosine phosphorylation in the presence of vanadate. Lavendustin produced time-dependent enhancement of vanadate-induced increase in [Ca2+]i. These results underscored the need for measuring cellular changes in protein tyrosine phosphorylation to assess potential functions of tyrosine kinase activity. Under conditions where changes in phosphorylation could be measured, the results suggested that AVP-activated increases in tyrosine phosphorylation may be coupled to AVP-activated mechanisms that regulate influx of extracellular Ca2+ and release of intracellular Ca2+.