Biomedical subjects

R Hudson

Publications and source records attributed to R Hudson.

At least 37 records · Page 2Linked to original sources

PubMed1999

Fragile X premutation is a significant risk factor for premature ovarian failure: the International Collaborative POF in Fragile X study--preliminary data.

The preliminary results of an international collaborative study examining premature menopause in fragile X carriers are presented. A total of 760 women from fragile X families was surveyed about their fragile X carrier status and their menstrual and reproductive histories. Among the subjects, 395 carried a premutation, 128 carried a full mutation, and 237 were noncarriers. Sixty-three (16%) of the premutation carriers had experienced menopause prior to the age of 40 compared with none of the full mutation carriers and one (0.4%) of the controls. Based on these preliminary data, there is a significant association between fragile X premutation carrier status and premature menopause.

Adolescent↗

PubMed1999

The flavor of life: perinatal development of odor and taste preferences.

Despite the importance of chemosensation in the regulation of ingestive behavior, we still know surprisingly little about the development of the olfactory, trigeminal and gustatory systems. All three, however, are functional to some degree prenatally, and by birth infants are able to respond to a wide range of odors and can clearly distinguish between the tastes of sweet, sour and bitter. Based on findings from our work in the rabbit, we report that learning of odors associated with the mother's diet can occur very early in development, even prenatally, that it can have a long-term influence on later food choice, and may even lead to enhanced, stimulus-specific sensitivity of the basic sensory apparatus. Whether comparable phenomena exist in human infants is not known, although our recent findings that nationalities differ in judgements of the pleasantness of food odors depending on whether these are recognized as representing familiar, culture-typical foods, suggests that it might. A cross-cultural study is currently in progress examining the influence of culture-specific childhood eating experiences on adult preferences for food-associated odors.

Adult↗

PubMed1999

From molecule to mind: the role of experience in shaping olfactory function.

The olfactory system is faced with a particular problem--the high dimensionality and inherent unpredictability of the chemical world. Most natural odorants encountered in everyday life are complex mixtures of many different volatiles. This means that from the outset the olfactory system has to contend with a great and often unpredictable diversity of molecules, making it difficult for stable primary features of the chemical world to be mapped onto the sensory surface. One solution to such unpredictability is provided by learning. Learning confers flexibility, enabling individuals of a given species to acquire and make use of the most appropriate information in a particular environment. Two examples of this are presented: learning of maternal odors in neonatal rabbits, including evidence that the sensory surface itself may be influenced by environmental conditions so as to enhance sensitivity to molecules of particular ecological relevance, and cross-cultural human studies suggesting that experience with everyday odors influences not only the way these are evaluated, but also their perceived intensity. It is concluded that an adequate understanding of odor coding and olfactory function will not be possible without taking such experience-dependent factors into account.

Animals↗

PubMed1999

Temporal and behavioral patterning of parturition in rabbits and rats.

Although the rabbit (Oryctolagus cuniculus) continues to play an important role in the study of parturitional processes, a detailed behavioral description of birth in this species, necessary for accurately assessing the effects of experimental manipulation, is lacking. It is the aim of this report to provide such a description and to compare it with corresponding behavior in the better-studied rat. Ten pregnant chinchilla-breed rabbits and 10 pregnant Wistar rats were placed in glass-bottomed observation cages 2 days before term, and their behavior recorded on closed-circuit video, viewing the animals from below. All aspects of parturition were accomplished much faster in rabbits than rats; latency to birth of first pup, rate of delivery, duration of vaginal retention, time spent by mothers eating placentas, and in licking and nursing pups. In contrast to rat pups, rabbits were usually born separated from the placenta and already free from membranes. They were much more active, and well able to cast off any remaining membranes, suckle, and survive, whether directly attended to by the mother or not. We conclude that the tight temporal organization of events in the rabbit provides an unusually sensitive assay for investigating mechanisms underlying mammalian parturition.

Animals↗

PubMed1999

Expression of c-fos in the main olfactory bulb of neonatal rabbits in response to garlic as a novel and conditioned odour.

Expression of c-Fos was examined in the olfactory bulbs of 3-day-old rabbits after they had been presented with the odour of garlic as a novel stimulus, as a learned odour, or during conditioning, and this expression compared with baseline levels in non-stimulated controls. Exposure to garlic odour resulted in substantial and widespread increases in c-Fos expression in the olfactory bulbs of all animals. However, although conditioned pups showed a specific behavioural response to the learned garlic odour, neither the amount nor pattern of c-Fos expression differed compared to pups exposed to garlic as a novel odour. The odour-induced expression of c-Fos was not well localised, although there was a significant increase in the number of granule cells expressing c-Fos in the ventrolateral region of the bulb. These results support previous reports that the response to odours in the olfactory bulb of new-born animals is not as spatially distinct as that in adults. Nevertheless, the immature olfactory system of these young animals is clearly capable of very specific odour learning.

Analysis of Variance↗

PubMed1999

Perception of everyday odors--correlation between intensity, familiarity and strength of hedonic judgement.

In this study, 40 Japanese, 44 German and 39 Mexican women were presented with 18 everyday odorants. They were asked to rate them for intensity on a six-point scale from not detectable to very strong, for pleasantness on an 11-point scale from -5, to neutral at 0, to +5, and for familiarity on a six-point scale from completely unknown to extremely familiar. Consistent positive correlations were found between paired rating scores for the three measures, and although they were not particularly strong (r(s) range, 0.19-0.60), for most odorants all three correlations were significant. Similar results were obtained whether the data were analyzed on an individual or a national basis. Most notable were the consistent positive correlations between perceived intensity and ratings of familiarity and hedonic strength. It is suggested that the perceived intensity of the odorants depended not only on stimulus concentration but probably also on experience-dependent factors.

Adult↗

PubMed1999

Effects of aerobic or resistance exercise and/or diet on glucose tolerance and plasma insulin levels in obese men.

OBJECTIVE: This study had two objectives. First, we examined whether the influence of diet combined with either aerobic (DA) (n = 10) or resistance (DR) (n = 10) exercise has effects on insulin and glucose levels that are different in obese men. Second, we tried to determine whether the combination of diet and exercise is associated with improvements in insulin and glucose levels that are greater than those associated with diet alone (DO) (n = 9). RESEARCH DESIGN AND METHODS: Insulin and glucose levels were measured after an overnight fast and a 75-g oral glucose challenge (OGTT). Visceral adipose tissue (AT), subcutaneous AT, and skeletal muscle were measured by magnetic resonance imaging (MRI) before and after treatment (16 weeks). RESULTS: Reductions in weight (12.4 +/- 3.8 kg) and in visceral (37 +/- 15.1%) and subcutaneous AT (24.3 +/- 8.6%) were not different between treatments (P > 0.05). Skeletal muscle was maintained in the DA and DR groups but was reduced (7.3 +/- 2.8%) in the DO group (P < 0.05). Independent of treatment, fasting glucose and OGTT glucose did not change (P > 0.05). However, fasting insulin, OGTT insulin, and the insulin-to-glucose ratio decreased within all treatments (P < 0.05). Reductions in the OGTT insulin area under the curve were greater (P < 0.05) within the DA (52 +/- 12%) and DR (42 +/- 17%) treatments than in the DO (20 +/- 15%) treatment. Collapsed across group, reductions in visceral AT were related to reductions in fasting and OGTT glucose (P < 0.05), whereas reductions in abdominal subcutaneous AT correlated with reductions in fasting insulin (P < 0.05). CONCLUSIONS: Weight loss induced by diet and aerobic or resistance exercise has similar positive effects on lowering fasting and OGTT insulin values that are greater than those with diet alone. Because changes in glucose and insulin were related to reductions in visceral and abdominal subcutaneous AT, we conclude that reduction in abdominal obesity consequent to diet and exercise-induced weight loss is important for attaining improvements in plasma insulin levels, observations that strengthen the concept that abdominal obesity has an important role in mediating insulin resistance.

Adipose Tissue↗

PubMed1998

Induced peripheral sensitivity in the developing vertebrate olfactory system.

The high dimensionality and unpredictability of the chemical world makes it difficult for the olfactory system to anticipate relevant stimuli and construct neural filters accordingly. A developmental solution to this problem would be to alter the sensory surface according to environmental conditions so as to enhance sensitivity to molecules of particular relevance. Evidence for this has been obtained in the rabbit. By feeding pregnant does aromatic juniper berries, it could be shown that newborn, weanling and even adult animals demonstrate a preference for juniper odor without subsequent postnatal experience, and that this is associated with enhanced peripheral sensitivity for juniper odor as measured by electro-olfactogram (EOG). This is consistent with the report that in young salmon olfactory imprinting is associated with enhanced, odor-specific sensitivity of receptor cells as measured by patch clamp. The mechanisms underlying such changes are unknown, including the extent to which they are a particular feature of developing systems.

Animals↗

PubMed1998

Differences and similarities in the perception of everyday odors. A Japanese-German cross-cultural study.

To investigate the influence of experience on odor perception the responses of 40 Japanese and 44 age-matched German women to everyday odorants were compared. Subjects were presented with six 'Japanese,' six 'European' and six 'international' odorants and asked to rate them on intensity, familiarity, pleasantness and edibility, and to describe associations elicited by them, and if possible to name them. Significant differences were found between the two populations on all measures, with a close association of pleasantness ratings and edibility judgments suggesting the particular influence of eating habits on odor perception. Positive correlations between familiarity and pleasantness, strength of hedonic judgment and intensity, and familiarity and intensity were also found in both groups and for most individuals. The generality of these findings was supported by the results obtained from testing 40 Mexican women with the same odorants.

Cultural Diversity↗

PubMed1998

A re-estimation of the number of glomeruli and mitral cells in the olfactory bulb of rabbit.

Although morphological characteristics of mammalian olfactory bulb (OB) are well documented in rodents (rat, mice), only one study has been performed in rabbit, which is also commonly used in olfactory research. The study carried out by Allison and Warwick in 1949 led to surprising results still quoted in recent literature. The present study re-examined this question in young rabbit OB, while it was also conducted with rat as control. In five animals of each species, areas and coordinates of glomeruli and mitral profiles were measured in 10 coronal sections uniformly distributed along the rostrocaudal axis of the OB, and a distribution-free stereological method was used to compute values along this axis. For glomeruli, the estimated number was 4200 in rat and 6300 in rabbit. While this estimation matched with those found in literature in rat, it strikingly differed from the Allison and Warwick's value of 1900 only. For mitral cell number, we found 59,600 while the preceding study found 45,000 only. In contrast to the number of glomeruli, the mitral cell number in rat and rabbit were very close. Indeed, results showed 56, 200 in rat. The results suggest that the numbers of olfactory glomeruli and mitral cells has been previously underestimated in rabbit, and that the number of glomeruli changes as a function of species. In addition, both the results of the present study and reports in the literature suggest the number of mitral cells to be rather similar in mouse, rat and rabbit. As a consequence, the glomerular/mitral cell ratio is likely to varied in a wide range across species.

Analysis of Variance↗

PubMed1998

Endogenous expression of C-Fos in hypothalamic nuclei of neonatal rabbits coincides with their circadian pattern of suckling-associated arousal.

Rabbits exhibit an unusually restricted form of maternal care. The newborn young are only nursed for about 3 min every 24 h and drink up to one third of their body weight in this time. They show a circadian increase in activity in anticipation of the doe's visit, which is entrained by suckling and appears analogous to feeding-entrained rhythms reported for other species. By investigating the expression of c-Fos protein in nursed and un-nursed pups at selected times before and after scheduled nursing, we were able to distinguish endogenous patterns of neuronal activation and patterns induced by suckling. Increased endogenous expression of c-Fos in the paraventricular thalamus and in the magnocellular neurons of the paraventricular hypothalamus coincided with the period of anticipatory arousal. By contrast, suckling induced c-Fos expression in the supraoptic nucleus and the parvocellular neurons of the paraventricular hypothalamus, whilst decreasing expression in the magnocellular neurons. Furthermore, the endogenous pattern of c-Fos expression was less distinct in 3-day-old compared to 7-day-old pups, suggesting maturational or experience-related influences on the neural correlates of the anticipatory arousal. In conclusion, the close correspondence between c-Fos expression and pups' endogenous rhythm of behaviour suggests that the rabbit's natural schedule of restricted nursing provides an ideal model in which to investigate the ontogeny of circadian function without disrupting the mother-offspring relationship or normal neonatal development.

Animals↗

PubMed1998

Alx-4, a transcriptional activator whose expression is restricted to sites of epithelial-mesenchymal interactions.

We have recently demonstrated that the retinoblastoma family of negative cell cycle regulators can form complexes with a class of developmental factors which contain paired-like (PL) homeodomains (Wiggan et al. [1998] Oncogene 16:227-236). Our screens led to the isolation of a novel PL-homeodomain protein which had been isolated independently by another group and called Alx-4 (Qu et al. [1997] Development 124:3999-4008). Mice homozygous for a targeted null mutation of Alx-4 have several abnormalities, including preaxial polydactyly, suggesting that Alx-4 plays a role in pattern formation in limb buds. In data that we present here, we show that Alx-4 is expressed in mesenchymal condensations of a diverse group of tissues whose development is dependent on epithelial-mesenchymal interactions, many of which are additionally dependent on expression of the HMG-box-containing protein, LEF-1. Alx-4-expressing tissues include osteoblast precursors of most bones, the dermal papilla of hair and whisker follicles, the dental papilla of teeth, and a subset of mesenchymal cells in pubescent mammary glands. We show further that Alx-4 strongly activates transcription from a promoter containing the homeodomain binding site, P2. Optimal activation requires specific sequences in the N-terminal portion of Alx-4 as well as a proline-rich region downstream of the PL-homeodomain, but not the paired-tail at the C terminus. Taken together, our results demonstrate that Alx-4 is a potent transcriptional activator that is expressed at sites of epithelial-mesenchymal interactions during murine embryonic development.

Animals↗

PubMed1998

The sensory but not muscular pelvic nerve branch is necessary for parturition in the rat.

In the rat the pelvic nerve consists of a viscerocutaneous (sensory) branch which receives information from pelvic viscera and the midline perineal region, and a somatomotor (muscular) branch which innervates the ilio- and pubococcygeous muscles. To investigate the contribution of these branches to the parturition process, the length of gestation and course of delivery were closely monitored in 43 pregnant, Wistar-strain rats randomly assigned to five groups: untreated control animals, animals in which the somatomotor branch of the pelvic nerve was bilaterally sectioned on Day 14 of gestation, animals in which the viscerocutaneous branch of the pelvic nerve was bilaterally sectioned on Day 14 of gestation, animals treated similarly to the previous group but with young delivered by C-section at term, and sham-operated controls. Sectioning the viscerocutaneous branch seriously disrupted parturition and resulted in major dystocia and a high percentage of stillbirths in all females. In contrast, sectioning the somatomotor branch had no apparent effect on parturition and no significant differences were found between females of this group and sham or control dams on any of the measures recorded. It is concluded that the viscerocutaneous branch of the pelvic nerve is vital for the normal course of parturition in the rat but that the somatomotor branch plays little role, if any.

Abdominal Muscles↗

PubMed1998

Differences in perception of everyday odors: a Japanese-German cross-cultural study.

There is a growing appreciation that experience with odors may strongly influence their perception. To further investigate this, the responses of 40 Japanese and 44 age-matched German women to everyday odorants were compared. Subjects were presented with 18 stimuli in squeeze bottles and asked to rate them according to intensity, familiarity, pleasantness and edibility, to describe associations elicited by them and, if possible, to name them. One-third of the odorants were presumed to be familiar to the Japanese only, one-third to the Germans and one-third to both populations. Significant differences were found between the two populations on all measures. Better performance by the Japanese in providing appropriate descriptors for 'Japanese' odorants and by the Germans for 'European' odorants supported the pre-selection of stimuli as culture-typical. Particularly clear differences between the two populations were found in pleasantness ratings. In general, a positive relationship was found between pleasantness and judgement of stimuli as edible, suggesting that culture-specific experiences-particularly of foods-may significantly influence odor perception. Somewhat unexpectedly, significant differences were also found between the two populations in intensity ratings for some odorants. These differences did not seem simply to be artefacts of the test situation and raise the possibility that experience may even influence such basic aspects of odor perception as stimulus intensity.

Cultural Characteristics↗

PubMed1997

Striated muscles and scent glands associated with the vaginal tract of the rabbit.

BACKGROUND: Despite the importance of the rabbit (Oryctolagus cuniculus) in reproductive research, no comprehensive account of the anatomical organization of the female reproductive tract is presently available. METHODS: Based on gross dissection and on the electrical stimulation of striated muscles in 10 domestic female rabbits, it was the aim of this study to help fill this gap by describing the origin, insertion, and general action of muscles associated with the vaginal tract and with associated scent glands. RESULTS: Compared with the better-studied rat or cat, the long vaginal tract of the rabbit is characterized by a well-developed and complex musculature. The bulbospongiosus, ischiocavernosus, constrictor vestibuli, and constrictor vulvae muscles, poorly developed or absent in the female rat or cat, were particularly conspicuous. Scent glands, including the newly identified preputial glands, were also a distinctive feature. CONCLUSION: These structures may represent specializations underlying the rapid copulation, rapid parturition, and well-developed chemical communication characteristic of the reproductive efficiency of the rabbit.

Animals↗

PubMed1997

Trigeminal perception of odorant quality in congenitally anosmic subjects.

Twenty congenitally anosmic subjects and 50 normosmic controls were tested for their ability (i) to assign verbal labels from a list of trigeminal-type descriptors to six odorants believed to have a strong trigeminal component; and (ii) to discriminate between intensity-matched pairs of these odorants in an odd-ball paradigm. The following was found: normosmic controls judged menthol and cineole as distinctly cool and fresh, acetic acid as pungent and sour, and acetone as pungent, but showed no clear descriptive profile for ethanol and propanol. The descriptive profiles given by the anosmic subjects correlated significantly with those given by the controls for three of the six odorants (menthol, cineol and ethanol), confirming that the sensations described may indeed be mediated by the trigeminal system. In the odd-ball test, the control subjects correctly identified an average of eight out of the nine items presented, with most mistakes occurring in response to pairs with a similar trigeminal profile. With an average of 7.2 of nine items correct, the performance of the anosmic subjects was not significantly different to that of the normosmics, except in discriminating between acetic acid and menthol. Although additional tests are necessary to decide finally whether differences in stimulus intensity may have contributed to this good discriminatory performance, the present results suggest that the nasal trigeminal system may contribute significantly to the perception of odor quality.

1-Propanol↗

PubMed1997

Stress and coping among African American and Hispanic parents of deaf children.

The authors conducted a correlational study of 98 parents of children with hearing loss to determine the relationships among the parents' stress levels, their reported coping strategies, and the demographic characteristics of themselves and their hearing-impaired children. One unexpected finding was the low level of stress expressed by the sample. One predicted relationship was found. The communicative ability through signing of the child was significantly related to level of stress. The predicted relationships between a parent's marital status, a parent's educational level, the child's sex, and the age at onset of the hearing loss were not confirmed. The study revealed that racial and ethnic group membership was significantly related to the degree of use of several coping strategies. Hispanics differed significantly from African Americans in that they made greater use of coping strategies.

Adaptation, Psychological↗

PubMed1996

Changes in pain threshold during the reproductive cycle of the female rat.

Responsiveness to pain was determined in female rats across the whole reproductive cycle using the tail-flick test. When tested immediately after mating, pain thresholds were unaltered, whereas 10 min later animals typically demonstrated hyperalgesia (Experiment 1). They also demonstrated hyperalgesia during most of pregnancy, and had significantly lower pain thresholds than the unmated controls except for the 24 h before parturition, when a sudden increase in tail-flick latencies was recorded (Experiment 2). Pain thresholds were also significantly lower throughout the nursing period but increased significantly when dams were separated from their litters for 6 h, and returned to premating baseline values within 24 h of weaning (Experiment 3). These findings confirm and extend earlier reports that female reproductive state may significantly modify responsiveness to noxious stimuli, and it is suggested that differences between the results of this and previous studies may be at least partly explained by the relatively stress-free test procedure adopted here.

Animals↗