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Studies of respiratory components and oxidative phosphorylation in mitochondria of mi-1 Neurospora crassa.

Oxidative phosphorylation has been demonstrated with mitochondria of the mi-1 respiratory mutant of Neurospora crassa. The P/O ratios observed with these mitochondria were approximately 0.8 with citrate and 0.4 with either externally added reduced nicotinamide adenine dinucleotide (NADH), succinate, or ascorbate-tetramethyl-p-phenylenediamine (TPD). These P/O ratios suggest that there are only two sites of phosphorylation in mitochondria isolated from young (20 to 24 h) cultures of the mi-1 mutant. The energy-dependent reduction of NAD(+) with succinate and the phosphorylation associated with ascorbate-TPD oxidation indicate that the first and the third sites of energy coupling are present in this mutant. Difference spectra of mitochondria from young cultures of the mi-1 mutant revealed the presence of cytochrome c. Cytochromes b and a + a(3) were not detected. However, in the presence of antimycin A, a small peak in the Soret region at 430 nm was observed. A carbon monoxide difference spectrum revealed the presence of a component of the respiratory chain with a spectrum similar to that of cytochrome o. It is of interest that respiratory inhibitors such as antimycin A, 2-n-nonylhydroxyquinoline N-oxide, and cyanide abolished phosphorylation but only partially inhibited oxidation. It is postulated that the mi-1 respiratory system contains two pathways of electron transport-the first is associated with a phosphorylating pathway, whereas the second is a non-phosphorylating electron transport pathway.

Antimycin A↗

Doppler echocardiographic estimation of left ventricular end-diastolic pressure after MI in rats.

The spectral Doppler mitral flow pattern, alone or combined with tissue Doppler mitral annulus velocity, can be used to predict left ventricular (LV) filling pressure in humans, whereas invasive hemodynamic measurements are still required in the rat. This study was undertaken to assess whether LV end-diastolic pressure (LVEDP) can be estimated using Doppler echocardiography in the rat after myocardial infarction (MI). Thirty-seven rats (23 rats with MI after left coronary artery ligation and 14 sham-operated rats) were evaluated 3 mo after surgery with echo-Doppler and invasive hemodynamic measurements. Pulse wave spectral Doppler at the mitral valve tip was used to measure the E wave, the E wave deceleration time (DT), and the A wave; spectral Doppler tissue imaging was used to measure the early diastolic lateral mitral annulus velocity (E(a)). We found weak correlations between LVEDP and the peak velocity of the early mitral inflow (E), E/peak velocity of the late mitral inflow, and DT, and strong correlations with E(a) and especially with E/E(a) [R(2) = 0.89, LVEDP (in mmHg) = 0.987E/E(a) - 4.229]. Longitudinal followup of a subgroup of rats with MI revealed a marked rise of E/E(a) between days 7 and 21 in rats with heart failure only. We conclude that Doppler echocardiography can be used for serial assessment of LV diastolic function in rats with MI.

Animals↗

Amiodarone and post-MI patients.

Amiodarone is a viable drug for preventing sudden cardiac death, particularly during the first year after MI. If larger trials confirm the aforementioned prospective trials of Ceremuzynski et al, Cairns et al, and the BASIS trial, the efficacy of amiodarone would outweigh the risk of its side effects during the first year after MI. Based on the long-term observation from the BASIS trial, the duration of amiodarone therapy need not be more than 1 year--which, as we have learned, is when these post-MI patients would benefit most from the drug. It is also likely that the effects of amiodarone would complement those of aspirin and angiotensin converting enzyme inhibitors. The SAVE, CONSENSUS II, and SOLVD trials demonstrated that captopril and enalapril did not reduce the mortality rate during the first year after MI, nor did they reduce the sudden cardiac death rate. Their beneficial effects became evident only during the second year and thereafter. Unlike other antiarrhythmic agents of various classes, amiodarone possesses antiarrhythmic properties but does not exert deleterious effects on ventricular function. More studies are needed to determine if the benefit of amiodarone could be enhanced by combination therapy (eg, angiotensin converting enzyme inhibitors, aspirin, or beta-blockers). Whether amiodarone will provide the same protection for patients who have poor left ventricular function or congestive heart failure is not known. The European and VA cooperative studies should help answer this question. If it turns out that amiodarone is beneficial, one must then determine whether higher doses of the drug will offer more protection, and, if so, if that greater protection would be offset by increased toxicity. How much amiodarone should be given to offer the most protection with the least risk? Another intriguing research question is this: If we treat patients with amiodarone for more than 1 year, would the drug continue to improve the mortality rate in subsequent years? Other studies are needed in patients at very high risk of sudden cardiac death (ie, those who have a low ejection fraction and high-density VPDs). A study comparing amiodarone and sotalol in high-risk patients for sudden cardiac death is also needed. These clinical studies should be carried out with basic science research investigating the actions of amiodarone at the molecular and cellular level in order to give us a better understanding of how the drug works.

Amiodarone↗

Different effect of various mutant MITF encoded by mi, Mior, or Miwh allele on phenotype of murine mast cells.

The mi locus encodes a member of the basic-helix-loop-helix-leucine zipper protein family of transcription factors (hereafter called MITF). Mutant alleles of mi, Mior, and Miwh are deletion or point mutation of the basic domain by which MITF binds DNA. The basic domain also has nuclear localization potential. In the present study, we compared the mast cell abnormalities of Mior/Mior and Miwh/Miwh mice with those of mi/mi mice, of which many have been described by us. The number of mast cells in the skin of Mior/Mior suckling mice was remarkably decreased from that observed in mi/mi suckling mice, but the number was normal in the skin of Miwh/Miwh suckling mice. The decrease in skin mast cells was more severe in the mi/mi embryos than in mi/mi suckling mice, but the magnitude of the decrease was comparable between Mior/Mior embryos and Mior/Mior suckling mice. The poor mRNA expression of granzyme B and tryptophan hydroxylase genes was observed in all cultured mast cells (CMCs) derived from the spleens of Miwh/Miwh, Mior/Mior, and mi/mi mice. However, the poor expression of mouse mast cell protease-4 (MMCP-4), MMCP-5, and MMCP-6 was observed only in Mior/Mior and mi/mi CMCs. MITF encoded by Miwh mutant allele (Miwh-MITF) showed deficient but demonstratable DNA binding, but mi-MITF and Mior-MITF did not show any DNA binding ability. Although Miwh-MITF and Mior-MITF showed normal nuclear localization potential, the potential was significantly impaired in mi-MITF. The rank order of mast cell abnormality (mi/mi > Mior/Mior > Miwh/Miwh) appears to be related to the functional abnormality of MITF encoded by each mutant gene.

Alleles↗

Silent MI. Prevalence and prognosis in older patients diagnosed by routine electrocardiograms.

Older men and women with coronary artery disease and silent myocardial ischemia detected by 24-hour ambulatory electrocardiograms (ECGs) have a higher incidence of new coronary events than those with no silent ischemia. The prevalence of clinically unrecognized MI detected by routine ECGs in older persons varies from 21 to 68%. Atypical symptoms associated with acute MI in older persons include dyspnea and neurologic and GI symptoms, as well as chest pain. Older persons with clinically unrecognized MI have a similar or higher incidence of new coronary events and mortality compared with those with recognized MI, which suggests that an aggressive diagnostic and therapeutic approach may be beneficial in these patients.

Aged↗

[Expression of p27 and proliferative (MIB-1), mitotic (MI) and apoptotic indices in early-phase (EGF) gastric carcinoma. Results of a study by the Italian Gastric Cancer Research Group (IRGGC)].

AIMS: Since the Japanese Society for Gastroenterology and Endoscopy (JSGE) introduced the definition of Early Gastric Cancer (EGC), much more and deeper studies were done, which demonstrated that EGC was a more complex phase of the neoplastic disease with different morphologic characteristics, tightly linked to the prognosis. We evaluated the clinical impact of some prognostic factors, known being important in the advanced lesions, in a series of EGC patients with special reference to the clinicomorphological features. METHODS AND RESULTS: We analysed the mitotic (MI) and apoptotic (AI) indices and the immunohistochemical expression of p27 and MIB-1 in 83 EGC cases consecutively recruited in the hospitals of Forlì, Verona, Siena and Milan (IRGGC) in the period 1994-95. The classifications of JSGE, Lauren and Kodama were used to define the macroscopic, microscopic and growth pattern types, respectively. Decreased p27 expression correlated with the macroscopic escavated lesions and diffused mixed histotypes; the increase of MIB-1 detection with tumour size larger than 2 cm, but lesser than 4 cm; MI with intestinal histologic types and AI with mucosal and penetrating lesions, according to Kodama. Statistical analysis showed significative correlations among MIB-1, MI and AI, but not with p27 and the other variables. All these factors did not influence the prognosis of our patients. CONCLUSIONS: In our series, p27, MIB-1, MI, and AI did not add any useful clinical. So, in EGC patients the morphological features have still the most important role in influencing the prognosis and treatment of patients.

Apoptosis↗

Superiority of Mi-ADMS to DMSA as parenteral treatment for decreasing mercury (203Hg) body burden in rats.

The efficiency of meso-2,3-dimercaptosuccinic acid (DMSA) and the monoisoamyl ester of meso-2,3-dimercaptosuccinic acid (Mi-ADMS) in decreasing 203Hg retention was evaluated in rats in relation to age and time of treatment. The experiments were performed on six-week- and seven-day-old Wistar rats, which received 203Hg by intraperitoneal administration. The chelators DMSA or Mi-ADMS were also administered intraperitoneally, twice, on two consecutive days, in doses of 0.25 mmol/kg body weight as early (0.5 and 24 h) or delayed treatment (24 and 48 h, or 48 and 72 h) after 203Hg administration. The retention of 203Hg was determined in the carcass, liver, kidneys and brain six days after administration using gamma scintillation counters (double crystal, well type). In all experimental conditions, regardless of the animals' age and time of chelation therapy, Mi-ADMS was found to be superior to DMSA in reducing the body burden of 203Hg in whole body and organs. Mi-ADMS therefore seems to be a very promising chelator in the treatment of mercury poisoning.

Animals↗

[The expression of the mutant gene mi in mouse aggregation chimeras].

Using aggregation of 8-cell embryos belonging to two mouse strains, we produced 17 chimeras, mi/mi<==>+/+ (3 organisms), mi/+<==>+/+ (9 organisms), and +/+<==>+/+ (5 organisms), that achieved the age of 30 days. Chimerism was identified by mosaic pigmentation of coat and retinal pigment epithelium (RPE). All mi/mi<==>+/+ chimeras suffered from microphthalmia. Disturbances of eye development in these mice were similar to those in mi/mi animals. In all three chimeras, pigmentation of RPE and choroid was represented with alternating pigmented and depigmented patches. Mosaic RPE pattern probably resulted from the effects of para-orbital mesenchyme cells of different genotypes, +/+ or mi/mi. These findings confirm our earlier data that mutant alleles of the mi locus affect ectomesenchyme (neural crest) cells playing an important role in normal RPE development. Coat pigmentation in mi/mi<==>+/+ chimeras had the same spotted pattern as in mi/+ heterozygous mice. Hence, the gene mi functions in melanoblasts, but dermal and epidermal mi/mi cells do not suppress migration, proliferation, and differentiation of +/+ melanoblasts. The mi/mi dermal cells do not interfere with the expression of the gene A. Despite the high proportion of mi/mi cells (58 to 80%), bone resorption and eruption of teeth in mi/mi<==>+/+ chimeras proceeded as in normal animals.

Alleles↗

Involvement of transcription factor encoded by the mi locus in the expression of c-kit receptor tyrosine kinase in cultured mast cells of mice.

The mi locus of mice encodes a member of the basic-helix-loop-helix-leucine zipper (bHLH-Zip) protein family of transcription factors (hereafter called MITF). Cultured mast cells of mi/mi genotype (mi/mi CMCs) did not normally respond to stem cell factor (SCF), a ligand for the c-kit receptor tyrosine kinase. The poor response of mi/mi CMCs to SCF was attributed to the deficient expression of c-kit both the mRNA and protein levels. The purpose of the present study is to investigate the effect of MITF on the transcription of the c-kit gene. First, we introduced cDNA encoding normal (+) MITF or mutant (mi) MITF into mi/mi CMCs using the retroviral vector. Overexpression of (+)-MITF but not mi-MITF normalized the expression of the c-kit and the poor response of mi/mi CMCs to SCF, indicating the involvement of (+)-MITF in the c-kit gene transactivation. Second, we analyzed the promoter of the c-kit gene. Three CANNTG motifs recognized by bHLH-Zip-type transcription factors were conserved between the mouse and human c-kit promoters. Among these three CANNTG motifs, only the CACCTG motif (nt -356 to -351) was specifically bound by (+)-MITF. When the luciferase gene under the control of the c-kit promoter was contransfected into NIH/3T3 fibroblasts with cDNA encoding (+)-MITF or mi-MITF, the luciferase activity significantly increased only when (+)-MITF cDNA was cotransfected. The deletion of the promoter region containing the CACCTG motif or the mutation of the CACCTG to CTCCAG abolished the transactivation effect of (+)-MITF, indicating that (+)-MITF transactivated the c-kit gene through the CACCTG motif. When the luciferase gene under the control of the c-kit promoter was introduced into the FMA3 mastocytoma and FEC-P1 myeloid cell lines, remarkable luciferase activity was observed only in FMA3 cells. Thus, the involvement of (+)-MITF in the c-kit transactivation appeared to be specific to the mast cell lineage.

Animals↗

Regulation of mouse mast cell protease 6 gene expression by transcription factor encoded by the mi locus.

The mi locus of mice encodes a member of the basic-helix-loop-helix-leucine zipper (bHLH-Zip) protein family of transcription factors (hereafter called MITF). Because the expression of the mouse mast cell protease 6 (MMCP-6) gene is remarkably reduced in mast cells of mi/mi mutant mice, we investigated the effect of MITF on the transcription of the MMCP-6 gene. First, we introduced the normal (+) MITF cDNA into mi/mi cultured mast cells using the retroviral vector. Overexpression of +-MITF but not mi-MITF normalized the expression of the MMCP-6 gene, indicating the involvement of +-MITF in the MMCP-6 gene transactivation. Second, we analyzed the promoter of the MMCP-6 gene by the transient cotransfection assay. The luciferase construct under the control of the MMCP-6 promoter and the cDNA encoding +-MITF or mi-MITF were cotransfected into NIH/ 3T3 fibroblasts. The coexpression of +-MITF but not mi-MITF increased the luciferase activity 10-fold. We found a CACATG and a CATCTG motif in the MMCP-6 promoter, both of which are generally recognized by bHLH-Zip-type transcription factors. We also found a GACCTG motif that was strongly bound by +-MITF. These three motifs were necessary for the 10-fold transactivation ability of the MMCP-6 promoter by +-MITF. Mutations of each motif significantly reduced the transactivation, suggesting that +-MITF directly transactivated the MMCP-6 gene through these three motifs.

3T3 Cells↗

Involvement of transcription factor encoded by the mouse mi locus (MITF) in expression of p75 receptor of nerve growth factor in cultured mast cells of mice.

The mi locus of mice encodes a member of the basic-helix-loop-helix-leucine zipper (bHLH-Zip) protein family of transcription factors (hereafter called MITF). Cultured mast cells (CMCs) of mi/mi genotype showed a poor response to nerve growth factor (NGF). Addition of NGF to the suboptimal dose of interleukin-3 (IL-3) increased the plating efficiency of normal (+/+) CMCs but not mi/mi CMCs. Although +/+ CMCs were berberine sulfate-negative when cultured with IL-3, +/+ CMCs became berberine sulfate-positive when cultured in the presence of both IL-3 and NGF, which suggested increased heparin content. In contrast, NGF did not influence the phenotype of mi/mi CMCs. The poor response of mi/mi CMCs to NGF was attributed to the deficient expression of p75 NGF receptor. The purpose of the present study is to examine the effect of MITF on p75 gene transcription. Overexpression of +-MITF or mi-MITF was observed in mi/mi CMCs to which cDNA encoding each type of MITF had been introduced using the retroviral vector. Overexpression of +-MITF but not of mi-MITF normalized the expression of p75 and the above-mentioned poor responses of mi/mi CMCs to NGF, indicating the involvement of +-MITF in p75 gene transactivation. Then, we analyzed the promoter of the p75 gene. Two CANNTG motifs recognized by bHLH-Zip-type transcription factors were conserved between the mouse and rat p75 promoters. One of these two CANNTG motifs was specifically bound by +-MITF. When the luciferase gene under the control of the p75 promoter was cotransfected into NIH/3T3 fibroblasts with cDNA encoding +-MITF or mi-MITF, luciferase activity increased significantly only when +-MITF cDNA was cotransfected. The mutation of this CANNTG motif abolished the transactivation effect of +-MITF, indicating that +-MITF transactivated the p75 gene, at least in part, through direct binding.

3T3 Cells↗

Mi-2 chromatin remodeling factor functions in sensory organ development through proneural gene repression in Drosophila.

Mi-2, the central component of the nucleosome remodeling and histone deacetylation (NuRD) complex, is known as an SNF2-type ATP-dependent nucleosome remodeling factor. No morphological mutant phenotype of Drosophila Mi-2 (dMi-2) had been reported previously; however, we found that rare escapers develop into adult flies showing an extra bristle phenotype. The dMi-2 enhanced the phenotype of ac(Hw49c), which is a dominant gain-of-function allele of achaete (ac) and produces extra bristles. Consistent with these observations, the ac-expressing proneural clusters were expanded, and extra sensory organ precursors (SOP) were formed in the dMi-2 mutant wing discs. Immunostaining of polytene chromosomes showed that dMi-2 binds to the ac locus, and dMi-2 and acetylated hisotones distribute on polytene chromosomes in a mutually exclusive manner. The chromatin immunoprecipitation assay of the wing imaginal disc also demonstrated a binding of dMi-2 on the ac locus. These results suggest that the Drosophila Mi-2/NuRD complex functions in neuronal differentiation through the repression of proneural gene expression by chromatin remodeling and histone deacetylation.

Acetylation↗

The TIMI risk score for unstable angina/non-ST elevation MI: A method for prognostication and therapeutic decision making.

CONTEXT: Patients with unstable angina/non-ST-segment elevation myocardial infarction (MI) (UA/NSTEMI) present with a wide spectrum of risk for death and cardiac ischemic events. OBJECTIVE: To develop a simple risk score that has broad applicability, is easily calculated at patient presentation, does not require a computer, and identifies patients with different responses to treatments for UA/NSTEMI. DESIGN, SETTING, AND PATIENTS: Two phase 3, international, randomized, double-blind trials (the Thrombolysis in Myocardial Infarction [TIMI] 11B trial [August 1996-March 1998] and the Efficacy and Safety of Subcutaneous Enoxaparin in Unstable Angina and Non-Q-Wave MI trial [ESSENCE; October 1994-May 1996]). A total of 1957 patients with UA/NSTEMI were assigned to receive unfractionated heparin (test cohort) and 1953 to receive enoxaparin in TIMI 11B; 1564 and 1607 were assigned respectively in ESSENCE. The 3 validation cohorts were the unfractionated heparin group from ESSENCE and both enoxaparin groups. MAIN OUTCOME MEASURES: The TIMI risk score was derived in the test cohort by selection of independent prognostic variables using multivariate logistic regression, assignment of value of 1 when a factor was present and 0 when it was absent, and summing the number of factors present to categorize patients into risk strata. Relative differences in response to therapeutic interventions were determined by comparing the slopes of the rates of events with increasing score in treatment groups and by testing for an interaction between risk score and treatment. Outcomes were TIMI risk score for developing at least 1 component of the primary end point (all-cause mortality, new or recurrent MI, or severe recurrent ischemia requiring urgent revascularization) through 14 days after randomization. RESULTS: The 7 TIMI risk score predictor variables were age 65 years or older, at least 3 risk factors for coronary artery disease, prior coronary stenosis of 50% or more, ST-segment deviation on electrocardiogram at presentation, at least 2 anginal events in prior 24 hours, use of aspirin in prior 7 days, and elevated serum cardiac markers. Event rates increased significantly as the TIMI risk score increased in the test cohort in TIMI 11B: 4.7% for a score of 0/1; 8.3% for 2; 13. 2% for 3; 19.9% for 4; 26.2% for 5; and 40.9% for 6/7 (P<.001 by chi(2) for trend). The pattern of increasing event rates with increasing TIMI risk score was confirmed in all 3 validation groups (P<.001). The slope of the increase in event rates with increasing numbers of risk factors was significantly lower in the enoxaparin groups in both TIMI 11B (P =.01) and ESSENCE (P =.03) and there was a significant interaction between TIMI risk score and treatment (P =. 02). CONCLUSIONS: In patients with UA/NSTEMI, the TIMI risk score is a simple prognostication scheme that categorizes a patient's risk of death and ischemic events and provides a basis for therapeutic decision making. JAMA. 2000;284:835-842

Aged↗

Sertraline treatment of major depression in patients with acute MI or unstable angina.

CONTEXT: Major depressive disorder (MDD) occurs in 15% to 23% of patients with acute coronary syndromes and constitutes an independent risk factor for morbidity and mortality. However, no published evidence exists that antidepressant drugs are safe or efficacious in patients with unstable ischemic heart disease. OBJECTIVE: To evaluate the safety and efficacy of sertraline treatment of MDD in patients hospitalized for acute myocardial infarction (MI) or unstable angina and free of other life-threatening medical conditions. DESIGN AND SETTING: Randomized, double-blind, placebo-controlled trial conducted in 40 outpatient cardiology centers and psychiatry clinics in the United States, Europe, Canada, and Australia. Enrollment began in April 1997 and follow-up ended in April 2001. PATIENTS: A total of 369 patients with MDD (64% male; mean age, 57.1 years; mean 17-item Hamilton Depression [HAM-D] score, 19.6; MI, 74%; unstable angina, 26%). INTERVENTION: After a 2-week single-blind placebo run-in, patients were randomly assigned to receive sertraline in flexible dosages of 50 to 200 mg/d (n = 186) or placebo (n = 183) for 24 weeks. MAIN OUTCOME MEASURES: The primary (safety) outcome measure was change from baseline in left ventricular ejection fraction (LVEF); secondary measures included surrogate cardiac measures and cardiovascular adverse events, as well as scores on the HAM-D scale and Clinical Global Impression Improvement scale (CGI-I) in the total randomized sample, in a group with any prior history of MDD, and in a more severe MDD subgroup defined a priori by a HAM-D score of at least 18 and history of 2 or more prior episodes of MDD. RESULTS: Sertraline had no significant effect on mean (SD) LVEF (sertraline: baseline, 54% [10%]; week 16, 54% [11%]; placebo: baseline, 52% [13%]; week 16, 53% [13%]), treatment-emergent increase in ventricular premature complex (VPC) runs (sertraline: 13.1%; placebo: 12.9%), QTc interval greater than 450 milliseconds at end point (sertraline: 12%; placebo: 13%), or other cardiac measures. All comparisons were statistically nonsignificant (P> or = .05). The incidence of severe cardiovascular adverse events was 14.5% with sertraline and 22.4% with placebo. In the total randomized sample, the CGI-I (P =.049), but not the HAM-D (P =.14), favored sertraline. The CGI-I responder rates for sertraline were significantly higher than for placebo in the total sample (67% vs 53%; P =.01), in the group with at least 1 prior episode of depression (72% vs 51%; P =.003), and in the more severe MDD group (78% vs 45%; P =.001). In the latter 2 groups, both CGI-I and HAM-D measures were significantly better in those assigned to sertraline. CONCLUSION: Our results suggest that sertraline is a safe and effective treatment for recurrent depression in patients with recent MI or unstable angina and without other life-threatening medical conditions.

Angina, Unstable↗

Interference of MI-D, a new mesoionic compound, on artificial and native membranes.

MI-D (4-phenyl-5-(4-nitrocinnamoyl)-1,3,4-thiadiazolium-2-phenylamine chloride), a new mesoionic compound, decreased the rate of swelling induced by valinomycin-K+, as well as induced swelling in the presence of nigericin-K+. Shrinkage was also affected, suggesting interference with the inner mitochondrial membrane, which would affect both fluidity and elasticity. Fluorescence polarization of DPH and DPH-PA, probing the core and outer regions respectively, of the DMPC and native membranes, indicated that MI-D shifts the midpoint of phase transition to higher values and orders of the fluid phase. These alterations in membrane fluidity are thus related to MI-D effects on the energy-linked functions of mitochondria.

Animals↗

Microphthalmia (mi) mice display an aberrant bone trace element composition.

It has been recognized that bone trace element composition analysis provides clues when analyzing bone-related physiological conditions. Increasing numbers of bone-related genetic diseases have been identified recently. In this study, we have analyzed bone trace element composition in a genetic mutant animal model. Mutations in the mouse microphthalmia (mi) gene affect the development of a number of cell types, including melanocytes, mast cells, and osteoclasts. Previous studies have shown that different alleles of the mi locus show osteopetrosis. In order to gain insights into the effects of a particular genetic defect on bone trace element composition and bone structure, we performed bone trace element composition analysis using inductively coupled plasma atomic emissions spectrometry (ICP-AES). Marked changes in bone trace element levels were found in vertebrate bones of mi mutant mice. The implications and possible applications of bone trace element analysis will be discussed in this article.

Animals↗

Test-retest reliability of the Extended Complex Figure Test--Motor Independent administration (ECFT-MI).

The Extended Complex Figure Test (ECFT; Fastenau, 1996b, 2003a), adds recognition and matching trials to the Rey-Osterrieth Complex Figure Test (ROCFT). An alternate administration of the ECFT, the ECFT-Motor Independent version (ECFT-MI; Fastenau, 2003a) measures visuospatial memory without the motoric demands of the ROCFT. ECFT-MI test-retest reliabilities were examined in 55 healthy adults tested two times separated by one week. The Recognition Trial showed strong reliability for the Total Score (r = .80, p < .0001). Reliabilities for Recognition Detail Scale and Subscales (r = .62-.74, p < .0001) and for the Global Scale (r = .51, p < or = .005) were attenuated by fewer items per subscale but were comparable to other memory tests. Matching Trial reliability coefficients were attenuated by extreme ceiling effects and restriction of range, but scores were very consistent between the two administrations. This study supports the temporal stability of the ECFT-MI.

Adult↗

Solution structure of alpha-conotoxin MI determined by 1H-NMR spectroscopy and molecular dynamics simulation with the explicit solvent water.

The conformation of alpha-conotoxin MI, a potent antagonist of the nicotinic acetylcholine receptor, has been investigated in aqueous solution. Two-dimensional NMR experiments and simulated annealing calculations provide the overall topology of alpha-conotoxin MI; then molecular dynamics simulation with the explicit solvent water was followed in order to obtain a more reliable solution structure. The resulting conformation indicates the presence of a 3(10) helix and a type I beta-turn for residues Pro6-Cys8 and Gly9-Try12, respectively, and shows a significant structural similarity to that of alpha-conotoxin GI, which has biological activity similar to that of MI. The present study provides a molecular basis for the alpha-conotoxin-receptor interaction.

Computer Simulation↗