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At least 649 records · Page 36Linked to original sources
PubMed2005

Bad bones, absent smell, selfish testes: the pleiotropic consequences of human FGF receptor mutations.

The discovery in 1994 that highly specific mutations of fibroblast growth factor (FGF) receptor 3 caused the most common form of human short-limbed dwarfism, achondroplasia, heralded a new era in FGF receptor (FGFR) biology. A decade later, the purpose of this review is to survey how the study of humans with FGFR mutations continues to provide insights into FGFR function in health and disease, and the clinical applications of these findings. Amongst the most interesting recent discoveries have been the description of novel phenotypes associated with FGFR1 and FGFR3 mutations; identification of fundamental differences in the cellular mechanisms of mutant FGFR2 and FGFR3 action; and the direct identification of FGFR2 and FGFR3 mutations in sperm. These clinical observations illustrate the pleiotropism of FGFR action and fuel ongoing efforts to understand the rich biology and pathophysiology of the FGF signalling system.

Bone Diseases, Developmental↗
PubMed2005

Olfactory bulb mitral cell dendritic pruning abnormalities in a mouse model of the Fragile-X mental retardation syndrome: further support for FMRP's involvement in dendritic development.

The Fragile-X mental retardation syndrome is the leading form of inherited mental retardation. Dendritic analysis in a mouse model (FraX) found abnormal pruning in somatosensory cortex. To further characterize dendritic abnormalities and assess their occurrence in other brain regions, we examined mitral cells in FraX mice olfactory bulbs. FraX mice exhibited dendritic abnormalities consistent with somatosensory cortex, suggesting that deficient pruning is found in multiple brain regions.

Animals↗
PubMed2005

How do children with adenoid hypertrophy smell and taste? Clinical assessment of olfactory function pre- and post-adenoidectomy.

OBJECTIVE: To assess the ability to smell and appreciate food in children with adenoid hypertrophy pre and post-adenoidectomy. METHODS: A total of 35 children with adenoid hypertrophy admitted for adenoidectomy (aged 5-9.3 years, mean age 5.9 years) were tested preoperatively. In a follow up appointment 3 months postoperatively, 28 of them returned and were tested again. The control group consisted of 30 healthy children (aged 5-10.2 years, mean age 6.1 years). Orthonasal olfactory function was assessed psychophysically using "Sniffin sticks" 12 item odor identification test. Retronasal olfaction was assessed using a collection of 12 grocery available powders applied to the oral cavity. RESULTS: Both orthonasal and retronasal olfactory function of the study group preoperatively were significantly lower in comparison with the results of the control group (p<0.0001). The difference in retronasal olfaction between groups was significantly higher in comparison with the difference in orthonasal odor identification (p=0.048). There is a strong correlation between adenoid hypertrophy grade and retronasal testing results (t=-5.461, p<0.0001), but not with the orthonasal results (t=-1.677, p=0.9). Significant improvement of orthonasal and retronasal olfaction was observed in the follow-up appointment (p<0.0001). Relative increase postoperatively was higher for the retronasal olfaction compared to orthonasal olfaction (p=0.0029). CONCLUSIONS: Children with adenoid hypertrophy have a reduced ability to smell, with retronasal olfactory function being more affected. Surgery had a greater impact on retronasal olfaction.

Adenoidectomy↗
PubMed2005

Olfactory dysfunction: a sequela of pediatric blunt head trauma.

OBJECTIVE: To evaluate olfactory function in children with blunt head trauma. METHODS: Eligible subjects were consecutive children presenting at San Diego Children's Hospital Emergency Department or Trauma Service with blunt head trauma. Thirty-seven head injured children mean age 10.11+/-2.74 were evaluated; 36 healthy age and gender matched community children, mean age 10.08+/-2.99, served as controls. The medical record was reviewed for clinical measures related to head injury (HI). All children underwent olfactory assessment with the San Diego Children's Odor Identification Test (SDOIT). Olfactory event-related potentials were recorded on a subset of head injured and control children. RESULTS: Three of 37 head injured children had olfactory dysfunction. The head injured hyposmics had signs of more severe head injury represented by lower Glasgow Coma Scores (GCS), 10.33+/-5.51, when compared to their normosmic counterparts with mean GCS of 14.06+/-2.82. When stratifying the head injured children by clinical measures, lower Glasgow Coma Score, and abnormalities on head CT scan were associated with poorer olfactory performance. CONCLUSION: Children with blunt head injury may suffer post-traumatic olfactory impairment. More severe head injuries are more likely to produce olfactory deficits. In cases of significant head injury, cranial nerve I evaluation is imperative.

Adolescent↗
PubMed2006

A review of 59 consecutive patients with lesions of the anterior cranial base operated on using the subcranial approach.

INTRODUCTION: Lesions of the anterior cranial fossa are still a challenge for the surgeon. Since Joram Raveh introduced the concept of a subcranial approach in 1978 it has been used in the treatment of lesions extending into the anterior cranial fossa. Our experience with the subcranial approach during the past 8 years at Turku University Central Hospital is described. PATIENTS: Fifty-nine consecutive patients underwent surgery using the subcranial approach for treating various benign and malignant neoplasms, for repair of frontobasal-midfacial fractures, and for repair of cerebrospinal fluid leaks. METHODS: Patient records were retrospectively reviewed, with special focus on surgical technique, early outcome, and complications. RESULTS: Nineteen of the patients were operated on because of combined fronto-naso-orbital and skull base fractures, 37 were tumour cases, and 3 patients required surgical repair for cerebrospinal fluid leakage. Significant complications consisted of two cases of meningitis. However, they were successfully treated with antibiotics. The most common late complaint was olfactory nerve dysfunction (44), other late complications such as diplopia (4), enophthalmos (2), scar tissue in the nasal cavity (2), and trigeminal nerve dysfunction (2) were also encountered. CONCLUSION: The subcranial approach affords exposure to the orbital, sphenoethmoidal, and clivus regions, as well as to the nasal and paranasal cavities. On the basis of this review, it is concluded that it is a safe and effective approach for treating lesions involving the anterior skull base.

Adolescent↗
PubMed2004

Antibodies to dorsal root ganglia and olfactory cells in a patient with chronic sensory neuropathy and anosmia.

We report the case of a 51-year-old woman with anosmia and chronic sensory ataxic neuropathy. Olfactory tests suggested neurosensory anosmia. Immunocytochemical analysis showed serum antibodies against dorsal root ganglion (DRG) cells and olfactory neurons, in the absence of other known causes of anosmia and sensory neuropathy. Clinical and laboratory data suggested a slow autoimmune process affecting dorsal root ganglion and olfactory cells.

Antibodies↗
PubMed2006

Taste in dementing diseases and parkinsonism.

Like with many sensory abilities a reduction of taste and smell occurs during aging. Since there are hints to an additional reduction in dementing diseases, we assessed 52 patients, 26 women and 26 men, who were presented to a memory clinic, using the Sniffin' Sticks, Whole Mouth and Taste Strip Tests. While smoking, alcohol consumption, intake of drugs and sex exerted only minor impact, age and the severity of cognitive impairment were of major importance. There was a moderate but significant correlation between the severity of dementia, taste and smell, even if the age effect was partialled out. Notably, patients with Parkinson syndrome showed worse taste and smell abilities than those without. Here the differences were indeed marked enough to play a possible role in making the diagnosis. This exploratory study confirms a mild reduction of gustatory function in dementing diseases over and beyond that of normal aging which--in addition to a reduction of smell--seems to be especially marked in Parkinson syndromes.

Adult↗
PubMed2004

Australian norms for a quantitative olfactory function test.

Quantitative olfactory assessment is often neglected in clinical practice, although olfactory loss can assist diagnosis and leads to significant morbidity. The aim of this study was to develop normative data for the Australian population for the 'Sniffin' Sticks', an internationally established olfactory function test. As in other populations, Australian females performed better than males and both lost olfactory function with age. From the normative data, criterion test scores for males and females were established for clinical classifications ('normosmic', 'hyposmic', and 'nosmic'). These clinical classifications were assessed in Parkinson's patients: 81.1% were anosmic or severely hyposmic and only 7.7% were normosmic. A new term ('rebyosmia') is introduced to describe age-related loss of olfactory capacity of unknown aetiology. With these norms, the Sniffin' Sticks can be used in the Australian population to compare an individual's olfactory function against the population of others of similar age and sex and to identify olfactory dysfunction.

Adolescent↗
PubMed2006

Paediatric phenotype of Kallmann syndrome due to mutations of fibroblast growth factor receptor 1 (FGFR1).

Kallmann syndrome characterised by hypogonadotropic hypogonadism (HH) and anosmia is genetically heterogeneous with X-linked, autosomal dominant and autosomal recessive forms. The autosomal dominant form due to loss of function mutation in the fibroblast growth factor receptor 1 (FGFR1) accounts for about 10% of cases. We report here three paediatric cases of Kallmann syndrome with unusual phenotype in two unrelated patients with severe ear anomalies (hypoplasia or agenesis of external ear) associated with classical features, such as cleft palate, dental agenesis, syndactylia, micropenis and cryptorchidism. We found de novo mutation in these two patients (Cys178Ser and Arg622Gly, respectively), and one inherited Arg622Gln mutation with intrafamilial variable phenotype. These genotype-phenotype correlations indicate that paediatric phenotypic expression of FGFR1 loss of function mutations is highly variable, the severity of the oro-facial malformations at birth does not predict gonadotropic function at the puberty and that de novo mutations of FGFR1 are relatively frequent.

Adolescent↗
PubMed2006

Assessment of olfactory and trigeminal function using chemosensory event-related potentials.

GOALS: To give an overview on the theoretical and practical applications of chemosensory event-related potentials. METHODS: Chemosensory event-related potentials (ERPs) may be elicited by brief and precisely defined odorous stimuli. Based on the principles of air-dilution olfactometry, a stimulator was developed in the late 1970s, which allows stimulation of the olfactory neuroepithelium and the nasal mucosa with no concomitant mechanical stimulation. Chemosensory ERPs were obtained after stimulation of the olfactory nerve (olfactory ERPs) or the trigeminal nerve (somatosensory or trigeminal ERPs). The characteristics of the stimulator for chemosensory research as well as the variables influencing the responses are discussed in this paper. RESULTS: Implementation and normative data from our department are reported with different clinical examples from otorhinolaryngologic clinic. The bulk of the evoked response consists of a large negative component (often referred to as N1), which occurs between 320 and 450 ms after stimulus onset. This component is followed by a large positive component, often referred to as P2, occurring between 530 and 800 ms after stimulus onset. Absence of olfactory ERPs and presence (even with subtle changes) of somatosensory ERPs is a strong indicator of the presence of an olfactory dysfunction. CONCLUSIONS: This review examines and discusses the methods of chemosensory stimulation as well as the electrophysiological correlates elicited by such stimuli. The clinical applications of chemosensory ERPs in neurology and otorhinolaryngology are outlined.

Animals↗
PubMed2006

Oscillatory cortical activity during a motor task in a deafferented patient.

Little is known about the influence of the afferent peripheral feedback on the sensorimotor cortex activation. To answer this open question we investigated the alpha and beta band task-related spectral power decreases (TRPow) in the deafferented patient G.L. and compared the results to those of six healthy subjects. The patient has been deafferented up to the nose for 24 years but her motor fibers are unaffected and she can perform complex motor tasks under visual control. We recorded EEG (58 scalp positions) as well as the exerted force during a visuomotor task. The subjects had to maintain in precision grip an isometric force at 15% of the maximal voluntary contraction. In the patient we found a significantly higher alpha band spectral power during rest and larger alpha TRPow decreases during the motor task when compared to the healthy subjects' data. In contrast, we did not observe any significant differences between patient and controls for the beta band TRPow. The results indicate an altered functional alpha band network state in the patient, probably due to the chronic deafferentation leading to a deep 'idling' state of the contralateral sensorimotor area.

Adult↗
PubMed2006

Impairment of odor recognition in Parkinson's disease caused by weak activations of the orbitofrontal cortex.

Olfactory dysfunction and abnormalities of olfactory brain structures are found in patients with Parkinson's disease (PD), and a number of studies have reported that olfactory dysfunction is caused by abnormalities of the central olfactory systems. We previously analyzed electroencephalograms (EEGs) and respiration simultaneously in normal subjects while testing for detection and recognition of odors. We identified changes in respiration pattern in response to odor stimuli and found inspiratory phase-locked alpha oscillations (I-alpha). The genesis of I-alpha were identified in olfactory-related areas including the entorhinal cortex, hippocampus, amygdale and orbitofrontal cortex with an EEG dipole tracing method. In the present study, we used the same protocol in PD patients and compared results of PD with those of age-matched controls. All PD patients detected odor, but 5 out of 10 showed impaired odor recognition. Changes in breathing pattern associated with emotional changes during exposure to odor stimuli were not observed in PD patients. I-alpha waveforms were not observed; however, positive waves followed by negative waves were identified approximately 100ms after inspiration onset. Dipoles of this component were localized in the entorhinal cortex for odor detection in all patients and in the entorhinal cortex and middle temporal gyrus for PD patients who could discriminate odors. Odor recognition in PD could be subserved by a different neural circuit from that of normal subjects, done through the temporal association cortex as a subsystem for recognizing the odor; however, the system may not be associated with the odor-induced emotions.

Aged↗
PubMed2005

ApoE gene and familial risk of Alzheimer's disease as predictors of odour identification in older adults.

The study examined odour identification ability in healthy older adults at increased risk for developing Alzheimer's disease (AD). We recruited a sample (n = 24) of siblings related to probable AD cases and an age-matched control sample (n = 47). All participants were genotyped for the presence of the ApoE epsilon4 allele. Performance on a simple olfactory task of odour identification was compared according to positive family history of AD and ApoE epsilon4 status. The sibling group showed an odour identification deficit compared to the control group. Whilst there was no independent influence of ApoE epsilon4 status on odour identification, there was a significant interaction between positive family history and ApoE epsilon4 status. Sibling epsilon4 carriers showed the greatest odour identification deficit and their performance was significantly poorer than both the sibling non-epsilon4 carrier and control epsilon4 carrier groups. Odour identification deficits like those reported here are considered to be early cognitive markers of incipient AD. In this respect, these findings support the need to both monitor individuals at increased risk of the disease and introduce olfactory-mediated cognitive tasks into the diagnostic setting.

Age Factors↗
PubMed2006

Chemosensory specific reduction of trigeminal sensitivity in subjects with olfactory dysfunction.

Humans with olfactory loss have been found to exhibit a decreased sensitivity of the chemosensory trigeminal system. It is not clear, whether the reduced trigeminal sensitivity is restricted to the chemosensitive properties of the trigeminal nerve, or whether it reflects a general decrease of trigeminal sensitivity which is also found for cutaneous afferents. To investigate the relationship between cutaneous somatosensory and intranasal chemosensory trigeminal sensitivity, 91 subjects were investigated. Forty-five of them were considered healthy controls, whereas 46 subjects had olfactory dysfunction. Subjects with olfactory dysfunction were found to have higher thresholds for CO2 than controls indicating lower trigeminal chemosensory sensitivity in subjects with olfactory dysfunction. Both etiology and degree of olfactory dysfunction appeared to have an impact on CO2 thresholds. In contrast, no such differences were found with regard to detection thresholds for electrical cutaneous stimulation. These results indicate that the decrease of trigeminal sensitivity in subjects with olfactory dysfunction is specific for chemosensory sensations.

Adult↗
PubMed2004

Effects of drugs on olfaction and taste.

The fact that so many varied medications reportedly affect taste and smell is a testament to the complexity of the gustatory and olfactory systems. The reception, transduction, propagation, and perception of a chemical tastant or odorant requires the effective operation of numerous mechanisms--all of which may be susceptible in one way or another to a prescribed medication. Just as a diuretic may block the apical ion channels on a taste bud, or an antifungal can inhibit cytochrome p450-dependent enzymes at the level of the receptors, a chemotherapeutic agent can destroy mitosis in a replicating receptor cell and a steroid can lead to candidal overgrowth on the tongue surface. Medications not only have a perceivable taste themselves at times, but they can alter the mechanisms responsible for the ultimate perception of tastes and smells--either by direct or secondary means. It should be emphasized, as noted earlier in this article, that while many medications are to blame for the impairment or distortion of the gustatory or olfactory systems, it is not uncommon that the underlying medical problem for which they are prescribed is actually the culprit. Examples include epilepsy, migraines, hypothyroidism, schizophrenia, infections, and cancer. In fact, simple partial seizures emanating from regions of the brain such as the amygdala, hippocampus, parietal operculum, and rolandic operculum can lead to the chemosensory sensations that are most commonly considered unpleasant, such as "rotten apples," "cigarette," "peculiar," or "vomitus". While removing or changing an offending medication can reverse the effects on smell or taste perception, it is important to remember that lasting impairment may occur. This is vital for a physician to recognize prior to prescribing a medication. It is also necessary to report this to patients who may be devastated by chemosensory alterations after starting a new medication (eg, pastry chef, perfumist, wine specialist, plumber). Among the "risks" in a risks/benefits discussion with a patient regarding the use of a new medication, alterations in olfaction and taste appear to play an increasingly recognized role.

Drug-Related Side Effects and Adverse Reactions↗
PubMed2004

Effects of head injury on olfaction and taste.

Traumatic events such as motor vehicle accidents, falls, or assaults can lead to dysfunction in olfaction or gustation. Mechanisms of posttraumatic olfactory dysfunction include direct injury to the sinonasal tract or olfactory epithelium, shearing effect on olfactory fibers at the cribriform plate, or brain contusion or intraparenchymal hemorrhage. Posttraumatic gustatory dysfunction is rare, but may occur as a result of direct injury to the tongue, injury to cranial nerves VII or IX, or brain contusion or hemorrhage. Evaluation of head-injured patients presenting with olfactory or gustatory complaints should include a thorough history, including assessment for pre-and posttraumatic chemosensory dysfunction and potential mechanisms of injury, complete head and neck examination including nasal endoscopy and cranial nerve testing, and focused radiographic imaging, usually CT of the sinuses and skull base. Formal olfactory and gustatory testing may be performed using various techniques, although in cases potentially involving litigation, methodologies able to detect malingering should be used. Treatable causes of chemosensory disturbance, most notably conductive olfactory losses caused by chronic rhinosinusitis or nasal obstruction, should be ruled out. In the event of neurosensory deficits, recovery may occur up to 12 to 18 months after the traumatic event. All patients should be counseled regarding the risks of their chemosensory deficits, and given suggestions for appropriate compensatory strategies.

Brain↗