Three-dimensional vestibular eye and head reflexes of the chameleon: characteristics of gain and phase and effects of eye position on orientation of ocular rotation axes during stimulation in yaw direction

We investigated gaze-stabilizing reflexes in the chameleon using the three-dimensional search-coil technique. Animals were rotated sinusoidally around an earth-vertical axis under head-fixed and head-free conditions, in the dark and in the light. Gain, phase and the influence of eye position on vestibulo-ocular reflex rotation axes were studied. During head-restrained stimulation in the dark, vestibulo-ocular reflex gaze gains were low (0.1-0.3) and phase lead decreased with increasing frequencies (from 100 degrees at 0.04 Hz to < 30 degrees at 1 Hz). Gaze gains were larger during stimulation in the light (0.1-0.8) with a smaller phase lead (< 30 degrees) and were close to unity during the head-free conditions (around 0.6 in the dark, around 0.8 in the light) with small phase leads. These results confirm earlier findings that chameleons have a low vestibulo-ocular reflex gain during head-fixed conditions and stimulation in the dark and higher gains during head-free stimulation in the light. Vestibulo-ocular reflex eye rotation axes were roughly aligned with the head's rotation axis and did not systematically tilt when the animals were looking eccentrically, up- or downward (as predicted by Listing's Law). Therefore, vestibulo-ocular reflex responses in the chameleon follow a strategy, which optimally stabilizes the entire retinal images, a result previously found in non-human primates.

Action of boron at the molecular level: effects on transcription and translation in an acellular system

It has been shown that boric acid has well-defined biological effects such as stimulation of wound healing in vivo, release of growth factors and cytokines, and increase of the extracellular matrice turnover. We examined its action at the molecular level, using cell-free systems of transcription (isolated placenta nuclei) and translation (wheat germ extract). We found that 10 mM boric acid greatly increased RNA synthesis, measured by absorbance at 260 nm (x 6.4) or by [3H]-UTP uptake (x 11). Full-length functional mRNA was produced because proteins of 14-80 kDa were translated. Among these proteins, factors involved in angiogenesis and, subsequently, in wound healing (VEGF and TGFbeta) were identified by slot blot, whereas growth factors such as FGF1 and TNFalpha were not detected. These results demonstrate that boron may contribute to biological cell activities at both the transcription and translation levels. However, the mechanism of action is still not known.

Bell's theorem and the problem of decidability between the views of Einstein and Bohr

Einstein, Podolsky, and Rosen (EPR) have designed a gedanken experiment that suggested a theory that was more complete than quantum mechanics. The EPR design was later realized in various forms, with experimental results close to the quantum mechanical prediction. The experimental results by themselves have no bearing on the EPR claim that quantum mechanics must be incomplete nor on the existence of hidden parameters. However, the well known inequalities of Bell are based on the assumption that local hidden parameters exist and, when combined with conflicting experimental results, do appear to prove that local hidden parameters cannot exist. This fact leaves only instantaneous actions at a distance (called "spooky" by Einstein) to explain the experiments. The Bell inequalities are based on a mathematical model of the EPR experiments. They have no experimental confirmation, because they contradict the results of all EPR experiments. In addition to the assumption that hidden parameters exist, Bell tacitly makes a variety of other assumptions; for instance, he assumes that the hidden parameters are governed by a single probability measure independent of the analyzer settings. We argue that the mathematical model of Bell excludes a large set of local hidden variables and a large variety of probability densities. Our set of local hidden variables includes time-like correlated parameters and a generalized probability density. We prove that our extended space of local hidden variables does permit derivation of the quantum result and is consistent with all known experiments.

A possible loophole in the theorem of Bell

The celebrated inequalities of Bell are based on the assumption that local hidden parameters exist. When combined with conflicting experimental results, these inequalities appear to prove that local hidden parameters cannot exist. This contradiction suggests to many that only instantaneous action at a distance can explain the Einstein, Podolsky, and Rosen type of experiments. We show that, in addition to the assumption that hidden parameters exist, Bell tacitly makes a variety of other assumptions that contribute to his being able to obtain the desired contradiction. For instance, Bell assumes that the hidden parameters do not depend on time and are governed by a single probability measure independent of the analyzer settings. We argue that the exclusion of time has neither a physical nor a mathematical basis but is based on Bell's translation of the concept of Einstein locality into the language of probability theory. Our additional set of local hidden variables includes time-like correlated parameters and a generalized probability density. We prove that our extended space of local hidden variables does not permit Bell-type proofs to go forward.

A multivariate analysis of 416 patients with glioblastoma multiforme: prognosis, extent of resection, and survival

OBJECT

The extent of tumor resection that should be undertaken in patients with glioblastoma multiforme (GBM) remains controversial. The purpose of this study was to identify significant independent predictors of survival in these patients and to determine whether the extent of resection was associated with increased survival time.

METHODS

The authors retrospectively analyzed 416 consecutive patients with histologically proven GBM who underwent tumor resection at the authors' institution between June 1993 and June 1999. Volumetric data and other tumor characteristics identified on magnetic resonance (MR) imaging were collected prospectively.

CONCLUSIONS

Five independent predictors of survival were identified: age, Karnofsky Performance Scale (KPS) score, extent of resection, and the degree of necrosis and enhancement on preoperative MR imaging studies. A significant survival advantage was associated with resection of 98% or more of the tumor volume (median survival 13 months, 95% confidence interval [CI] 11.4-14.6 months), compared with 8.8 months (95% CI 7.4-10.2 months; p < 0.0001) for resections of less than 98%. Using an outcome scale ranging from 0 to 5 based on age, KPS score, and tumor necrosis on MR imaging, we observed significantly longer survival in patients with lower scores (1-3) who underwent aggressive resections, and a trend toward slightly longer survival was found in patients with higher scores (4-5). Gross-total tumor resection is associated with longer survival in patients with GBM, especially when other predictive variables are favorable.

Survival and recurrence factors in adult medulloblastoma: the M.D. Anderson Cancer Center experience from 1978 to 1998

Medulloblastoma is a rare adult primary brain tumor for which limited retrospective studies are available to elucidate natural history or to guide therapy. A retrospective chart and imaging review of adult patients (aged >18 years) with medulloblastoma was performed to identify survival and prognostic factors. Fifty-seven patients were evaluated at the University of Texas M.D. Anderson Cancer Center from 1978-1998. Statistical analysis of prognostic factors and overall survival was performed for a subgroup of 28 patients who were followed exclusively at our institution from the time of diagnosis until death or last follow-up. These 28 patients had an overall survival of 91% at 3 years and 84% at 5 years, whereas median survival was not reached after a median follow-up of 168 weeks (range, 9-602 weeks). Progression-free survival for all patients was 68% at 3 years and 62% at 5 years, and was not statistically different between poor- and standard-risk patients. Univariate analysis of clinical features, such as age, sex, extent of local disease, extent of resection, and use of adjuvant chemotherapy, did not identify any prognostic variables for survival among the 28 patients. Patterns of recurrence revealed that the posterior fossa was the most common site (56%), followed by bone marrow (25%). Adult medulloblastoma appears to have a favorable prognosis after treatment with maximally surgically feasible resection followed by craniospinal irradiation. Optimal treatment remains to be clarified, as both standard-risk and poor-risk patients have prolonged disease-free survival. The marked difference between survival and progression-free survival suggests that salvage therapy, usually with combination chemotherapy in this cohort of patients, is of benefit. More formal analysis of the survival benefit was not possible, however, because of the small number of patients treated at recurrence with any one therapeutic regimen.

McLeod syndrome: a novel mutation, predominant psychiatric manifestations, and distinct striatal imaging findings

The McLeod syndrome is an X-linked disorder caused by mutations of the XK gene encoding the XK protein. The syndrome is characterized by absent Kx erythrocyte antigen, weak expression of Kell blood group system antigens, and acanthocytosis. In some allelic variants, elevated creatine kinase, myopathy, neurogenic muscle atrophy, and progressive chorea are found. We describe a family with a novel point mutation in the XK gene consisting of a C to T base transition at nucleotide position 977, introducing a stop codon. Among seven affected males, five manifested with psychiatric disorders such as depression, bipolar disorder, or personality disorder, but only two presented with chorea Positron emission tomography and magnetic resonance volumetry revealed reduced striatal 2-fluoro-2-deoxy-glucose (FDG) uptake and diminished volumes of the caudate nucleus and putamen that correlated with disease duration. In contrast, none of 12 female mutation carriers showed psychiatric or movement disorders. However, a semidominant effect of the mutation was suggested by erythrocyte and blood group mosaicism and reduced striatal FDG uptake without structural abnormalities. Therefore, patients with psychiatric signs or symptoms segregating in an X-linked trait should be examined for acanthocytosis and Kell/Kx blood group serology.

Phase I bioequivalency study of MitoExtra and mitomycin C in patients with solid tumors

BACKGROUND

This study compares serum pharmacokinetics, urinary excretion patterns, and relative bioequivalencies of single doses of MitoExtra (ME; SuperGen, San Ramon, CA) and mitomycin C (MMC).

METHODS

Thirty-five patients were entered into this open-label, single-institution, crossover study with 2 treatment arms. Each patient received alternating courses of ME and MMC as 15 mg/m(2) single intravenous doses via a short intravenous infusion. Patients were sequentially assigned to receive either ME or MMC as their first treatment course. The courses were given in 6-week intervals and could be repeated up to 4 times in patients with responding disease. Pharmacokinetic parameters were analyzed during the first two courses of therapy.

RESULTS

The noncompartmental pharmacokinetic analysis conducted on serum and urine data obtained from patients who received both ME and MMC indicates that the kinetic disposition of these two formulations is similar. This is evident when the mean (+/- standard deviation) values of the various pharmacokinetic parameters are compared. There were no significant differences in any of the kinetic parameters obtained between treatments in all patients examined. The statistical evaluation conducted on the 25 patients that completed both arms of the 2-way pharmacokinetic crossover demonstrates that ME is bioequivalent to MMC. Hematologic and nonhematologic toxicities were similar between the two treatments. There were three clinically significant infusion-related complications associated with MMC administration and none associated with ME.

CONCLUSIONS

The similar pharmacokinetics of MMC and ME suggest complete release of MMC from the hydroxypropyl-Beta-cyclodextrin carrier contained in the ME formulation. Further studies are needed to define the pharmacodynamics, toxicity, and efficacy of this drug-carrier complex.

The paraoxonase Leu-Met54 and Gln-Arg191 gene polymorphisms are not associated with the risk of coronary heart disease

BACKGROUND

Evidence has been presented that gene polymorphisms (PON54 L/M, PON191 Q/R) of paraoxonase are risk factors of coronary heart disease.

RESULTS

We determined both PON genotypes in 535 male individuals who were free of vascular disease and in 2249 male subjects who underwent coronary angiography, and analysed the relation of both gene variations to CAD and MI. Both gene polymorphisms were in linkage disequilibrium (P<0.0001). Coronary artery disease: the PON54 gene polymorphism was not associated with an increased risk of CAD. In the total sample and also in younger subjects, an association of the PON191 gene variation with the risk of CAD was not detected when the control group of individuals without coronary heart disease was compared with patients with at least one diseased vessel (verified by coronary angiography). In individuals younger than 62 years, a moderate increase in the relative risk of CAD associated with the PON191 R allele (1.45 (1. 08-1.95); P=0.015) were found, when subjects without vessel disease (verified by coronary angiography) were compared with CAD patients. Myocardial infarction: an association of the PON54 gene variation with MI was not detected when the control group of individuals without coronary heart disease were compared with patients with at least one MI. A marginal increase in the risk of MI associated with the PON54 LL genotype (OR 1.27 (1.05-1.51); P=0.011) were detected when patients without MI but with coronary angiography were compared with MI positive patients. Subgroup analyses of low- and high-risk populations did not reveal any association of both PON gene polymorphisms with CAD or MI.

CONCLUSION

The present findings do not strengthen the hypothesis that the paraoxonase gene polymorphisms are independently associated with coronary heart disease indicating that these gene variations are of little usefulness as genetic markers of cardiovascular disease.

Effects of boron derivatives on extracellular matrix formation

Boric acid solution (3%) dramatically improves wound healing through action on the extracellular matrix, a finding that has been obtained in vitro. Consequently, investigations are presently underway to produce boronated compounds having a therapeutical effectiveness similar to that of boric acid. On the basis of experimental results obtained with boric acid, we examined the effects of boron derivatives on extracellular matrix formation and degradation and analyzed their potential toxicity by using two biological models (chick embryo cartilage and human fibroblasts). The four boron derivatives tested in this study (triethanolamine borate; N-diethyl-phosphoramidate-propylboronique acid; 2,2 dimethylhexyl-1,3-propanediol-aminopropylboronate and 1,2 propanediol-aminopropylboronate) mimicked the effects of boric acid. They induced a decrease of intracellular concentrations in extracellular matrix macromolecules (proteoglycans, proteins)-associated with an increase of their release in culture medium and stimulated the activity of intra- and extracellular proteases. Similarly to boric acid, these actions occurred after exposure of the cells to concentrations of all boron derivatives without apparent toxic effects. The compounds were found to be more toxic than boric acid itself when concentrations were calculated according to their molecular weight. Nevertheless, these in vitro preliminary results demonstrate effects of boron derivatives that may be of therapeutic benefit in wound repair.

[Mucopolysaccharidosis type I in Morocco: clinical features and genetic profile]

BACKGROUND

Mucopolysaccharidoses (MPS) are inherited metabolic disorders due to lysosomal enzyme deficiencies, leading to glycosaminoglycan accumulation in lysosomes of different tissues. The aim of this study was to characterize MPS types, particularly MPS I, which are difficult to differentiate by clinical features.

PATIENTS AND METHODS

Over a period of three years (June 1996-May 1999), 16 Moroccan patients (3-20 years old) with MPS were investigated. Twelve of them came from the Souss region. In subjects with suspected clinical MPS I or II, the diagnosis was confirmed by biochemical investigations, which included the quantification of total glycosaminoglycans (GAGs) released in urine, their identification, and the assay of alpha-L-iduronidase activity in leucocytes. A molecular analysis was performed in parallel, to provide the genetic proof of the diagnosis.

RESULTS

These 16 patients belonged to 12 families, nine of which were consanguineous (75%). Twelve patients had Hurler syndrome and three had Hurler/Scheie's syndrome; no case of Scheie's syndrome was observed. Short stature, coarse face, organomegaly, hernia, cardiac disease, mental delay and dysostosis were observed in variable degrees. We report three cases without corneal clouding. Increased total urinary GAGs, identified as dermatan sulfate and heparan sulfate by thin-layer chromatography and total deficiency of alpha-L-iduronidase activity, were noted in studied subjects. At the molecular level the P533R mutation was detected in 24 among 26 alleles studied.

CONCLUSION

It is now possible to perform the screening of MPS I and II in Morocco by analysis of clinical, radiologic observations and biological investigation. The predominance of P533R mutation could permit the screening of healthy heterozygotes and genetic counselling for families of Moroccan descent.

A phase II trial of high-dose bromodeoxyuridine with accelerated fractionation radiotherapy followed by procarbazine, lomustine, and vincristine for glioblastoma multiforme

PURPOSE

To conduct a Phase II study to evaluate the long-term efficacy and safety of high-dose 5'-bromodeoxyuridine (BrdU) and accelerated radiotherapy followed by procarbazine, lomustine (CCNU), and vincristine (PCV) chemotherapy in patients with glioblastoma multiforme.

METHODS AND MATERIALS

Between 1994 and 1996, 88 patients were enrolled to receive 1.9 Gy of radiation three times a day for two 5-day cycles separated by 2 weeks; each 5-day cycle was preceded by a continuous 96-hour infusion of BrdU at a dose of 2.1 g/m2/day. After radiotherapy, patients received PCV chemotherapy.

RESULTS

Median survival for all 88 patients was 50 weeks. Seventy (79.5 %) received one or more courses of PCV; their median survival was 57 weeks. Covariates predictive of improved survival were gross total versus subtotal resection or biopsy (p = 0.0048) and radiation dose > or = 56 Gy (p = 0.019). While receiving BrdU, 47 patients (53%) suffered grade 3 or 4 thrombocytopenia or leukopenia; 22 patients (25%) suffered grade 3 or 4 dermatologic toxicity.

CONCLUSION

Survival was not extended in patients with glioblastoma or gliosarcoma who received BrdU at the dose and administration schedule used in this study. The BrdU dose used in this study resulted in substantial myelosuppressive and dermatologic toxicity.

cDNA expression array reveals heterogeneous gene expression profiles in three glioblastoma cell lines

Tumor cell lines are an indispensable tool for cancer research. However, among cell lines of the same pathological group, heterogeneity has been detected in gene expression, gene mutation, and cellular response to various treatments. In this study, we systematically investigated the extent of heterogeneity of gene expression in three glioblastoma cell lines using cDNA array technology in which the expression of 588 cellular genes is studied simultaneously. Comparison of the expression profiles revealed substantial qualitative and quantitative heterogeneity. Among the 588 genes, 197 genes were expressed in all three lines and 56 genes were not expressed in any of the three lines; total of 222 genes were expressed in only two of the three cell lines, and 113 genes were expressed in only one of the three cell lines. These results provide molecular evidence that cell lines of the same pathological origin can be highly heterogeneous.

[Screening of olfaction with smell diskettes]

BACKGROUND

Aim of the study was the development of a new screening test of olfaction with reusable diskettes as odorant applicators.

METHODS

A screening test of olfaction was designed using 8 diskettes containing different odorants. The diskettes can be opened to release the odor and are closed after testing. The test was designed as a triple forced multiple choice test using a questionnaire, resulting in a score from 0 to 8 correct answers. Ninety-one volunteers with a normal sense of smell and 13 patients with subjective hyposmia or anosmia were tested to validate the developed test. The same volunteers were also tested with the sniffin' sticks test, another screening test of olfaction that is already validated. After testing, the volunteers were asked to compare the two tests.

RESULTS

Among the 91 volunteers with normal sense of smell, 10 achieved a score of 7, and 81 a score of 8 in the smell disk test. The 13 patients with hyposmia or anosmia achieved a score between 0 and 5. Based on the test design, there is a probability of 99.74% that a person who achieves a score of 7 or 8 will have normal olfaction. In the sniffin' sticks test, 85 volunteers with normal sense of smell achieved a score in the normal range for this test (6-8) whereas 6 volunteers were below with a score of 4 or 5. The 13 patients with hyposmia or anosmia scored between 0 and 6. The smell disk test was preferred by 86 persons, the sniffin' sticks test by 5, and 12 assessed both tests as equal.

CONCLUSIONS

The developed screening test is reliable for identifying patients with a normal sense of smell, and it can distinguish them from patients with hyposmia and anosmia. The diskettes proved to be reliable and comfortable applicators for odorants in clinical practice.