Flash Suppression Reveals an Additional Nonvisual Extrastriate Contribution for Amblyopic Suppression

Purpose

A growing body of evidence suggests that anomalous binocular interactions underlie the deficits in amblyopia, but their nature and neural basis are still not fully understood.

Methods

We examined the behavioral and neural correlates of interocular suppression in 13 adult amblyopes and 13 matched controls using a flash suppression paradigm while recording steady-state visual evoked potentials. The strength of suppression was manipulated by changing the contrast (10%, 20%, 30%, or 100%) of the flash stimulus, or the suppressor, presented either in the dominant (fellow) or nondominant (amblyopic) eye.

Results

At the behavioral level, interocular suppression in normal observers was found, regardless of the eye origin of the flash onset. However, the pattern of suppression in the amblyopes was not symmetric, meaning that the suppression from the dominant eye was stronger, supporting a putative chronic suppression of the amblyopic eye. Interestingly, the amblyopic eye was able to suppress the dominant eye but only at the highest contrast level. At the electrophysiology level, suppression of the steady-state visual evoked potential responses in both groups in all conditions was similar over the occipital region, but differed over the frontal region.

Conclusions

Our findings suggest that, although suppression in amblyopia involves an imbalanced interaction between the inputs to the two eyes in the visual cortex, there is also involvement of nonvisual extrastriate areas.

[Nutritional management of patients with head and neck cancer treated with radiation]

Radiotherapy and chemotherapy are standard treatment of head and neck cancer alone or associated to surgical treatment. Early (during treatment or the following weeks) and late side effects contribute to malnutrition in this population at risk. In this context, nutritional support adapted by dietary monitoring and enteral nutrition (nasogastric tube or gastrostomy) are often necessary. The early identification of the patients with high malnutrition risk and requiring enteral nutrition is necessary to improve the tolerance and efficacy of treatment.

[Radiotherapy of a glioma in a pregnant woman: evaluation of the foetal dose in conformational 3D or intensity-modulated]

The purpose was to assess three treatments planning techniques including one in intensity-modulated radiation therapy (IMRT) for cerebral irradiation of pregnant woman, in order to limit the dose delivered to the foetus. The treatment provided was 60 Gy to the planning target volume. Estimated foetal dose was measured using an anthropomorphic phantom, on the upper and middle part of the uterus. The first plan consisted in four beams in conformational technique delivered from a Varian accelerator with a 120 leaves collimator, the second one used non-coplanar fields and the third one assessed IMRT. With the conformational technique, the dose at the upper part of the uterus was 8.3 mGy and 6.3 mGy at the middle part. The dose delivered to the foetus was higher with the non-coplanar fields. In IMRT, the dose at the upper part of the uterus was 23.8 mGy and 14.3 mGy at the middle part. The three plans used 6 MV X-rays. Because of the use of leaves and non-coplanar fields, IMRT does not seem to be the optimal technique for the treatment of pregnant woman. However, the dose delivered to the foetus remains low and below the dose of 100 mGy recommended by the International Commission of Radiological Protection. It seems possible to consider the use of this technique for a better sparing of organs at risk for the mother.

Does father know best? Social learning from kin and non-kin in juvenile ringdoves

Parent-offspring transmission is usually thought to be the major route for cultural learning. We tested this assumption in ringdoves (Streptopelia risoria), a flock feeding Columbid that is easily raised in captivity. An aviary study first determined the foraging associations of juveniles placed with their sibling, their parents and a pair of non-kin adults. Juveniles foraged more often with kin than with non-kin and joined food discoveries in proportion to these foraging associations; aggression was relatively rare and came more often from unrelated adults than from parents. Two cage experiments showed that parents were not copied more often than unrelated adults when the two tutor types provided different, but equally productive, solutions to a feeding problem. Neither the ingestion of unfamiliar food (two seed types the juveniles had never encountered) nor the learning of a new food searching skill (opening a box containing seed) showed a differential effect of father versus non-kin tutors. Animals that scramble compete for food may thus acquire social information from whatever knowledgeable individuals are present, whether these are kin, unrelated conspecifics or heterospecifics.

The organization of grooming in budgerigars

Structural rules for grooming are examined in the budgerigar (Melopsittacus undulatus). Two types of bouts are found: short bouts with no predictable temporal pattern and long bouts with some degree of periodic occurrence. Transitions in long bouts are mostly based on anatomical proximity. Grooming movements cluster together according to function and body region. Evidence for hierarchical organization obtained by clustering is confirmed by the proportion of occurrence of movements in long and short bouts. Individual birds are similar enough on measures of occurrence, transition and hierarchica structure for pooling of subjects to be justified; this suggests that the organizational rules found here are to a large extent species-typical.

The opening of milk bottles by birds: Evidence for accelerating learning rates, but against the wave-of-advance model of cultural transmission

One of the most widely cited cases of cultural transmission in animals is the opening of milk bottles by British birds. Bottle opening was first reported in Swaythling in 1921 and its spread from that date to 1947 was mapped by Fisher and Hinde (1949). Using data from Fisher and Hinde, this paper tests two quantitative models of cultural transmission: (1) the logistic model describing the cumulative number of bottle opening sites in the Belfast area and in the whole of the UK, and (2) the linear wave-of-advance model describing the progressive spread over time of bottle opening from its presumed single point of origin, Swaythling. For both the UK and Belfast, the logistic provides a poorer fit than alternative accelerating functions: the positive exponential and the reverse S-shaped hyperbolic sine respectively yield the best corrected fits to the Belfast and UK data. Neither functions have the terminal deceleration phase typical of the logistic, but both have an accelerating phase consistent with the cultural assumption of an auto-catalytic increase in the rate of spread over time. For both Belfast and the whole UK, the wave-of-advance model can clearly be rejected, even with the addition of a second source of innovation in County Durham. The results support the view that bottle opening originated from several independent sites, but spread through an accelerating process that could have included direct and/or indirect social influences.

Beckwith-Wiedemann and Silver-Russell syndromes: opposite developmental imbalances in imprinted regulators of placental function and embryonic growth

Beckwith-Wiedemann syndrome (BWS) and Silver-Russell syndrome (SRS) are two congenital disorders with opposite outcomes on fetal growth, overgrowth and growth restriction, respectively. Although both disorders are heterogeneous, most cases of BWS and SRS are associated with opposite epigenetic or genetic abnormalities on 11p15.5 leading to opposite imbalances in the expression levels of imprinted genes. In this article, we review evidence implicating these genes in the developmental regulation of embryonic growth and placental function in mouse models. The emerging picture suggests that both SRS and BWS can be caused by the simultaneous and opposite deregulation of two groups of imprinted genes on 11p15.5. A detailed description of the phenotypic abnormalities associated with each syndrome must take into consideration the developmental functions of each gene involved.

Independent appearance of an innovative feeding behaviour in Antillean bullfinches

Behavioural innovations have been largely documented in birds and are thought to provide advantages in changing environments. However, the mechanisms by which behavioural innovations spread remain poorly known. Two major mechanisms are supposed to play a fundamental role: innovation diffusion by social learning and independent appearance of the same innovation in different individuals. Direct evidence for the independent emergence of the same innovation in different individuals is, however, lacking. Here, we show that a highly localized behavioural innovation previously observed in 2000 in Barbados, the opening of sugar packets by Loxigilla barbadensis bullfinches, persisted more than a decade later and had spread to a limited area around the initial site. More importantly, we found that the same innovation appeared independently in other, more distant, locations on the same island. On the island of St-Lucia, 145 km from Barbados, we also found that the sister species of the Barbados bullfinch, the Lesser Antillean bullfinch Loxigilla noctis developed the same innovation independently. Finally, we found that a third species, the Bananaquit Coereba flaveola, exploited the bullfinches' technical innovation to benefit from this new food source. Overall, our observations provide the first direct evidence of the independent emergence of the same behavioural innovation in different individuals of the same species, but also in different species subjected to similar anthropogenic food availability.

Sintering behaviour of 45S5 bioactive glass

In this study, we report on the effect of Bioglass structural transformations on its sintering behaviour. While heating up to 1000 degrees C, five successive transformations occur: glass transition, glass-in-glass phase separation, two crystallization processes and a second glass transition. The sintering of the material exhibits two main shrinkage stages associated with the two glass transitions at 550 and 850 degrees C. At 580 degrees C, the glass-in-glass phase separation induces a decrease in the sintering rate immediately followed by the major crystalline phase crystallization (Na(2)CaSi(2)O(6)) between 600 and 700 degrees C, from the surface to the bulk of the particles. A complete inhibition of sintering takes place followed by a minor shrinkage effect due to crystallization. A plateau is then observed until the second glass transition temperature is reached. A modification of Frenkel's model allows the determination of the glass-in-glass phase separation kinetics and the identification of the structural transformations effects on sintering behaviour.

Androgenetic/biparental mosaicism causes placental mesenchymal dysplasia

BACKGROUND

Placental mesenchymal dysplasia (PMD) is a distinct syndrome of unknown aetiology that is associated with significant fetal morbidity and mortality. Intrauterine growth restriction is common, yet, paradoxically, many of the associated fetuses/newborns have been diagnosed with Beckwith-Wiedemann syndrome (BWS).

METHODS

We report two cases of PMD with high levels of androgenetic (complete paternal uniparental isodisomy) cells in the placenta and document, in one case, a likely androgenetic contribution to the fetus as well.

RESULTS

The same haploid paternal complement found in the androgenetic cells was present in coexisting biparental cells, suggesting origin from a single fertilisation event.

CONCLUSIONS

Preferential allocation of the normal cells into the trophoblast explains the absence of trophoblast overgrowth, a key feature of this syndrome. Interestingly, the distribution of androgenetic cells appears to differ from that reported for artificially created androgenetic mouse chimeras. Androgenetic mosaicism for the first time provides an aetiology for PMD, and may be a novel mechanism for BWS and unexplained intrauterine growth restriction.

Randomized study comparing the "sniffing position" with simple head extension for laryngoscopic view in elective surgery patients

BACKGROUND

The "sniffing position" is recommended for optimization of glottic visualization under direct laryngoscopy. However, no study to date has confirmed its superiority over simple head extension. In a prospective, randomized study, the authors compared the sniffing position with simple head extension in orotracheal intubation.

METHODS

The study included 456 consecutive patients. The sniffing position was obtained by placement of a 7-cm cushion under the head of the patient. The extension position was obtained by simple head extension. The anesthetic procedure included two Laryngoscopies without paralysis: the first was used for topical glottic anesthesia. During the second direct laryngoscopy, intubation of the trachea was performed. The head position was randomized as follows: group A was in the sniffing position during the first Laryngoscopy and the extension position during the second, group B was in the extension position during the first laryngoscopy and the sniffing position during the second. Glottic exposure was assessed by the Cormack scale.

RESULTS

The sniffing position improved glottic exposure (decreased the Cormack grade) in 18% of patients and worsened it (increased the Cormack grade) in 11% of patients, in comparison with simple extension. The Cormack grade distribution was not significantly modified between the two groups. Multivariate analysis showed that reduced neck mobility and obesity were independently related to improvement in laryngoscopic view with application of the sniffing position.

CONCLUSIONS

Routine use of the sniffing position appears to provide no significant advantage over simple head extension for tracheal intubation in this setting. The sniffing position appears to be advantageous in obese and head extension-limited patients.

Selection for transgene homozygosity in embryonic stem cells results in extensive loss of heterozygosity

Embryonic stem cells offer unprecedented opportunities for random or targeted genome alterations in the mouse. We present here an efficient strategy to create chromosome-specific loss of heterozygosity in embryonic stem cells. The combination of this method with genome-wide mutagenesis in ES cells (using chemical mutagens or gene-trap vectors) opens up the possibility for in vitro or in vivo functional screening of recessive mutations in the mouse.

Characterization of wheat-flour-water doughs: a new method using ultrasound

In this paper, an original method of evaluating the physical properties of wheat-flour-water systems using high-frequency low-power ultrasound is presented. Most of the experiments were performed with a reflectance technique measuring the acoustic impedance of doughs. The velocity of propagation, attenuation and viscoelastic moduli have been evaluated for both compressional and shear ultrasonic waves in the interval 2-10 MHz for doughs of different hydrations. The 53% water content was found to be critical with respect to the presence of free water. The influence of the mixing and rest times on the longitudinal ultrasonic parameters is also studied.

Relative size of the hyperstriatum ventrale is the best predictor of feeding innovation rate in birds

Within the avian telencephalon, the dorsal ventricular ridge (DVR) contains higher order and multimodal integration areas. Using multiple regressions on 17 avian taxa, we show that an operational estimate of behavioral flexibility, the frequency of feeding innovation reports in ornithology journals, is most closely predicted by relative size of one of these DVR areas, the hyperstriatum ventrale. Neither phylogeny, juvenile development mode, nor species sampled account for the relationship. Similar results are found when the hyperstriatum ventrale is lumped with a second DVR structure, the neostriatum. In simple correlations, size of the wulst and the striatopallidal complex is associated with feeding innovation rate, but the two structures are eliminated from the multiple regressions. Our results parallel those on primates showing a correlation between innovation rate and neocortex size and support the idea that the mammalian neocortex and the neostriatum-hyperstriatum ventrale complex in birds have similar integrative roles.

Rhythmical eye-head-torso rotation alters fore-aft head stabilization during treadmill locomotion in humans

A repetitive manoeuvre called torso rotation (TR) is known to temporarily reduce the gain of the horizontal vestibulo-ocular reflex by 10-15% in healthy humans. TR consists of a series of rhythmical rotations of the eyes, head and upper body executed continuously for 30 minutes while standing. Our aim was to investigate whether TR affects the ability to hold the head in a fixed fore-aft position relative to space while walking on a treadmill with eyes closed. Ten healthy subjects stood in a carefully standardized position on a stationary treadmill. The treadmill started unexpectedly and ran for 4 s at 29 cm/s. The test stimulus was a linear acceleration in the fore-aft direction at the moment of treadmill start-up. Linear head position (i.e., ability to stabilize the head) was measured during and following the stimulus. A mechanical system prevented head rotation. Two series of 60 trials were performed before TR (control 1 and control 2 series) and one after TR. Before TR, subjects drifted rearward at an average drift velocity +/- S.D. = 3.1 +/- 0.9 cm/s. This drift was reasonably stable over time within and between the two control series. After TR, head holding ability was further impaired, with subjects having more difficulty to stabilize their head after treadmill start-up. In the first 10 trials after the arrest of TR, the average drift velocity was significantly larger than before TR(6.1 +/- 1.5 cm/sec, p < 0.01). Recovery to control values followed a roughly exponential time course, with 67% recovery occurring in the first 3.4 minutes after TR. Our results indicate that TR impairs the ability to sense and/or respond to fore-aft linear accelerations of the head following treadmill start-up in the absence of vision.

Trace element content of commercial shampoos: impact on trace element levels in hair

Popular shampoos were screened for their contents in trace elements, using ICP-MS detection in a semi-quantitative mode. Hair samples from volunteers were analyzed before and after hair washing with selected shampoos to demonstrate the effect of the contamination and the impact on occupational medicine. While some shampoos showed high levels of certain elements, the degree of contamination on the hair was found to be negligible. Only one shampoo tested, formulated with selenium sulfide, was found to seriously contaminate the hair.

Abnormal maternal behaviour and growth retardation associated with loss of the imprinted gene Mest

Mest (also known as Peg1), an imprinted gene expressed only from the paternal allele during development, was disrupted by gene targeting in embryonic stem (ES) cells. The targeted mutation is imprinted and reversibly silenced by passage through the female germ line. Paternal transmission activates the targeted allele and causes embryonic growth retardation associated with reduced postnatal survival rates in mutant progeny. More significantly, Mest-deficient females show abnormal maternal behaviour and impaired placentophagia, a distinctive mammalian behaviour. Our results provide evidence for the involvement of an imprinted gene in the control of adult behaviour.

Factors associated with abusive relationships among maltreated and nonmaltreated youth

This study sought to understand how experiences of maltreatment occurring prior to 12 years of age affect adolescent peer and dating relationships. A school-based sample of 15-year-olds was divided into maltreated (n = 132) and nonmaltreated (n = 227) subgroups based on self-reported maltreatment. These two groups were then compared on two theoretically determined dimensions of adjustment (i.e., interpersonal sensitivity/hostility; personal resourceS) and self- and teacher-report measures of peer and dating relationships. Findings supported the hypothesis that maltreated youths significantly differed from nonmaltreated youths in terms of adjustment problems as well as conflict with dating partners and close friends. Maltreated youths reported significantly more verbal and physical abuse both toward and by their dating partners, and were seen by teachers as engaging in more acts of aggression and harassment toward others. In regression analyses, the significant association between maltreatment and dating conflict for males was strengthened by including adjustment dimensions in the equation; for females, adjustment variables mediated the association between maltreatment and dating conflict. Results are discussed in relation to a maladaptive interpersonal trajectory for maltreated children, wherein a violent interactional dynamic in adolescent close relationships may be setting the stage for violence in intimate partnerships.

Embryonic germ cells induce epigenetic reprogramming of somatic nucleus in hybrid cells

Genomic reprogramming of primordial germ cells (PGCs), which includes genome-wide demethylation, prevents aberrant epigenetic modifications from being transmitted to subsequent generations. This process also ensures that homologous chromosomes first acquire an identical epigenetic status before an appropriate switch in the imprintable loci in the female and male germ lines. Embryonic germ (EG) cells have a similar epigenotype to PGCs from which they are derived. We used EG cells to investigate the mechanism of epigenetic modifications in the germ line by analysing the effects on a somatic nucleus in the EG-thymic lymphocyte hybrid cells. There were striking changes in methylation of the somatic nucleus, resulting in demethylation of several imprinted and non-imprinted genes. These epigenetic modifications were heritable and affected gene expression as judged by re-activation of the silent maternal allele of Peg1/Mest imprinted gene in the somatic nucleus. This remarkable change in the epigenotype of the somatic nucleus is consistent with the observed pluripotency of the EG-somatic hybrid cells as they differentiated into a variety of tissues in chimeric embryos. The epigenetic modifications observed in EG-somatic cell hybrids in vitro are comparable to the reprogramming events that occur during germ cell development.

Genomic structure and parent-of-origin-specific methylation of Peg1

We previously identified Peg1/Mest as a novel paternally expressed gene in the developing mouse embryo. The human PEG1 gene was recently assigned to 7q32 and shown to be imprinted and paternally expressed. Therefore, PEG1 deficiency could participate in the aetiology of pre- and post-natal growth retardation associated with maternal uniparental disomy 7 in humans. We have now initiated the characterization of the Peg1 locus in order to identify and dissect cis-acting elements implicated in its imprinted monoallelic expression. The genomic structure of Peg1 as well as the DNA sequence of the 5'-end of the gene, including 2.4 kb of promoter sequences and covering the first 2 exons, have been determined. Important sequence elements, such as a CpG island spanning exon 1 and direct repeats, are identified and discussed. To address the role of epigenetic modifications in the imprinting of Peg1, a methylation analysis of the Peg1 gene is presented. Partially methylated cytosine residues in 13.5 d.p.c. embryos and undifferentiated ES cells were identified. Using embryos carrying a targetted mutation at the Peg1 locus, we show that this partial promoter methylation pattern reflects a strict parent-of-origin-specific differential methylation: the expressed paternal allele is unmethylated, whereas the silenced maternal allele is fully methylated at the CpG sites studied. That the gametes carry the epigenetic information necessary to lay down this allele-specific methylation pattern is suggested by analysis of DNA isolated from sperm and parthenogenetic embryos.

Mode of foraging competition is related to tutor preference in Zenaida aurita

This study compared the direction of social learning in 2 populations of Barbados Zenaida doves (Zenaida aurita). One population (St. James) is territorial; it competes aggressively with conspecifics but scramble competes with heterospecifics. The other population (Deep Water Harbour) forages in large homospecific flocks. Field observations were conducted to quantify intraspecific and interspecific patterns of foraging association and aggression. Wild-caught doves from both areas were then tested on novel foraging tasks demonstrated by either a conspecific or a heterospecific tutor. In all experiments, St. James doves learned more readily from the heterospecific tutor (Carib grackle -Quiscalus lugubris-), whereas Deep Water Harbour doves learned more readily from the conspecific tutor. The type of competitive feeding interaction in the field (i.e., scramble vs. interference) appears to better predict the pattern of social learning in an experiment than does species identity.

Mutational and functional analysis of dominant SPT2 (SIN1) suppressor alleles in Saccharomyces cerevisiae

The Saccharomyces cerevisiae SPT2 gene was identified by genetic screens for mutations which are suppressors of Ty and delta insertional mutations at the HIS4 locus. The ability of spt2 mutations to suppress the transcriptional interference caused by the delta promoter insertion his-4-912 delta correlates with an increase in wild-type HIS4 mRNA levels. The SPT2 gene is identical to SIN1, which codes for a factor genetically defined as a negative regulator of HO transcription. Mutations in SPT2/SIN1 suppress the effects of trans-acting mutations in SWI genes and of partial deletions in the C-terminal domain of the largest subunit of RNA polymerase II. Nuclear localization and protein sequence similarities suggested that the SPT2/SIN1 protein may be related to the nonhistone chromosomal protein HMG1. To assess the significance of this structural similarity and identify domains of SPT2 functionally important in the regulation of his4-912 delta, we have studied recessive and dominant spt2 mutations created by in vitro mutagenesis. We show here that several alleles carrying C-terminal deletions as well as point mutations in the C-terminal domain of the SPT2 protein exhibit a dominant suppressor phenotype. C-terminal basic residues necessary for wild-type SPT2 protein function which are absent from HMG1 have been identified. The competence of these mutant SPT2 proteins to interfere with the maintenance of the His- (Spt+) phenotype of a his4-912 delta SPT2+ strain is lost by deletion of internal HMG1-like sequences and is sensitive to the wild-type SPT2+ gene dosage. Using cross-reacting antipeptide polyclonal antibodies, we demonstrate that the intracellular level of the wild-type SPT2 protein is not affected in presence of dominant mutations and furthermore that the reversion of the dominance by internal deletion of HMG1-like sequences is not mediated by altered production or stability of the mutant polypeptides. Our results suggest that the products of dominant alleles directly compete with the wild-type protein. On the basis of primary sequence similarities, we propose that an HMG-box-like motif is required for SPT2 function in vivo and that this motif also is necessary for the dominant suppressor phenotype exhibited by some mutant SPT2 alleles.

Influence de la croissance et de facteurs du milieu sur l'alimentation du crabe des neiges, Chionoecetes opilio (O. Fabricius), dans le sud-ouest du golfe du Saint-Laurent

The stomach contents of snow crabs (Chionoecetes opilio) of carapace width >0.6 cm and <7.3 cm were examined in 650 specimens collected at the entrance of the Chaleur Bay, in the southwestern region of the Gulf of St. Lawrence. Individuals were collected with a beam trawl at depths of 70–120 m, on gravelly–muddy and muddy substrates, during the summers of 1986 and 1987. A repletion iridex (RI) was estimated and the daily feeding rhythm of early benthic stages (carapace width <3.0 cm) was determined while considering four classes of RI on 246 crabs. A significant difference between day and night in RI was observed, indicating nocturnal feeding activity in early benthic stages of snow crab, as is the case in the older stages. The mineral content of stomachs, as determined by burning, increases proportionally with the size of the crab. Diet is dominated by crustacea (85% of stomachs), followed by polychaeta (83%) and mollusca (19%). A correspondence analysis conducted on preys and variables (depth, substratum, and size of crab) showed common feeding preferences for crabs of the same size in spite of environmental disparity.

The ANB1 locus of Saccharomyces cerevisiae encodes the protein synthesis initiation factor eIF-4D

The Saccharomyces cerevisiae anaerobic gene (ANB1) is negatively regulated both by oxygen and heme. We have shown recently that an upstream repressor site located in the 5'-flanking region of this gene controls its expression (Mehta, K.D., and Smith, M. (1989) J. Biol. Chem. 265, 8670-8675). In this paper, we present the complete genomic sequence of the ANB1 locus of S. cerevisiae. The ANB1 locus encodes a protein of 157 residues with an Mr of 17, 134. The deduced amino acid sequence of the ANB1 gene product shows strikingly extensive sequence and structural homology (63.5% identical residues and an additional 15% conservative substitutions) to the 154-amino-acid-long human and rabbit eukaryotic translation initiator factor (eIF)-4D. Factor eIF-4D is the only known mammalian protein that undergoes a unique post-translational modification of Lys-50 to the amino acid hypusine, and interestingly the same lysine is also present in the ANB1 gene product. Results presented provide strong evidence that the ANB1 locus that encodes a transcript, tr-2, and a second locus encoding a transcript, tr-1, together encode two forms of yeast eIF-4D. Interestingly, heme regulates both the loci in an opposite manner; as a result it can dictate the isoform available under conditions of high and low oxygen tension. The ROX1 locus of S. cerevisiae is known to regulate CYC1, COXVb, and ANB1 genes at the transcriptional level; the ROX1 locus thus regulates all known anaerobically expressed genes that are involved in different cellular functions such as respiration and protein synthesis.

Retirement and mortality

The impact of retirement on morbidity and mortality in Canada is examined. "The mortality experience of a cohort of 15,260 men and 5,632 women, retiring in 1970 at the age of 65, is compared with corresponding age-specific death rates observed in the general Canadian population between 1970-74." The mortality differentials observed are analyzed by sex.