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P D'Haese

Publications and source records attributed to P D'Haese.

11 recordsLinked to original sources
PubMed2001

Rate influences on tone burst summating potential amplitude in electrocochleography: clinical(a) and experimental(b) data.

Electrocochleographic recordings of action and summating potentials are widely used in the electrophysiological assessment of endolymphatic hydrops (ELH). Increased amplitudes of the summating potential (SP) in response to tone burst stimuli are indicative of positive ELH. This study reports the effect of repetition rate of tone burst stimulation on the SP amplitude. Using transtympanic electrocochleography (ECochG), the SP in response to 1 kHz tone bursts was recorded in both a Ménière and a non-Ménière population. Absolute values of the SP were systematically higher in the Ménière group. Moreover, in the Ménière and non-Ménière groups, the response amplitudes of the SP at a repetition rate of 8.4 tone bursts/s were only 66 and 32%, respectively, of the maximal response amplitude which was obtained at the rate of 37.4 tone bursts/s. Additionally, in normal guinea pigs chronically implanted with a round window electrode, the SP was recorded to 0.5-16 kHz tone burst stimulations presented at 100 dB SPL with the same different repetition rates. Similar enhancement of the SP amplitude was observed from 8.4 to 37.4 stimuli/s, whatever the frequency. This effect is interpreted as an increased asymmetry of vibration of the cochlear partition, whose mechanical operating point would not return to the normal resting position at high repetition rates, since it is permanently shifted in ELH.

Acoustic Stimulation↗
PubMed2000

Audiometric analysis of a Belgian family linked to the DFNA10 locus.

OBJECTIVE: To report the otologic and audiometric characteristics of a nonsyndromic postlingual sensorineural hearing impairment in a Belgian family linked to DFNA10. STUDY DESIGN: Retrospective study of the otologic and audiometric data of 17 genetically affected persons. SETTING: Tertiary referral center. PATIENTS: All members of a Belgian kindred who carried the haplotype linked to the inherited hearing impairment of DFNA10. INTERVENTIONS: Diagnostic otologic and audiometric analysis. MAIN OUTCOME MEASURES: Pure-tone audiometry. RESULTS: To find the frequencies that were most affected by the genetic defect, the excess hearing loss of the 17 patients was calculated per frequency in comparison with the respective p50 and p95 thresholds of the normal population. CONCLUSIONS: The genetically affected persons of a Belgian family shared a progressive symmetric sensorineural hearing loss that started in the first to fourth decade. Thirty-five percent of the affected family members had tinnitus, and only one patient had very mild vestibular complaints. At onset, hearing losses were mainly situated at the midfrequencies. With increasing age, all frequencies became affected. The hearing loss was initially mild, with a spontaneous evolution to a moderate or severe hearing impairment. The progression of the hearing loss for the pure-tone average (between 0.5 and 4 kHz) was 1.08 dB/year for this family, compared with 0.50 dB/year and 0.35 dB/year at the 95th and 50th percentiles of the normal population, respectively.

Adult↗
PubMed1999

High prevalence of symptoms of Menière's disease in three families with a mutation in the COCH gene.

We report the genetic analysis of one large Belgian and two small Dutch families with autosomal dominant non-syndromic progressive sensorineural hearing loss associated with vestibular dysfunction. Linkage studies in the Belgian family mapped the disease to the DFNA9 locus on chromosome 14. Mutation analysis of the COCH gene, which is responsible for DFNA9, revealed a missense mutation changing a highly conserved residue. One of the patients, who had an earlier age of onset in comparison with most of the affected family members, was shown to be homozygous for the mutation. After the mutation was found in the Belgian family, we discovered that the same missense mutation was also present in two Dutch families with similar cochleo-vestibular symptoms. In all three families with hearing loss and imbalance problems, >25% of the patients showed additional symptoms, including episodes of vertigo, tinnitus, aural fullness and hearing loss. Clinically, these symptoms are consistent with the criteria for Menière's disease. The importance of genetic factors in Menière's disease has been suggested on many occasions, but this study is the first report of a mutation in a gene leading to the symptoms of Menière's disease in a significant portion of the carriers. The COCH gene may be one of the genetic factors contributing to Menière's disease and the possibility of a COCH mutation should be considered in patients with Menière's disease symptoms.

Chromosomes, Human, Pair 14↗
PubMed1998

Lead absorption and renal dysfunction in a South African battery factory.

OBJECTIVES: To test the association between inorganic lead (Pb) exposure, blood pressure, and renal function in South African battery factory workers, with both conventional and newer measures of renal function and integrity. METHODS: Renal function measures included serum creatinine, urea, and urate (n = 382). Urinary markers (n = 199) included urinary N-acetyl-beta-D-glucosaminidase (NAG), retinol binding protein, intestinal alkaline phosphatase, tissue non-specific alkaline phosphatase, Tamm-Horsfall glycoprotein, epidermal growth factor, and microalbuminuria. RESULTS: Mean current blood Pb was 53.5 micrograms/dl (range 23 to 110), median zinc protoporphyrin 10.9 micrograms/g haemoglobin (range 1.9 to 104), and mean exposure duration 11.6 years (range 0.5 to 44.5). Mean historical blood Pb, available on 246 workers, was 57.3 micrograms/dl (range 14 to 96.3). After adjustment for age, weight and height, positive exposure response relations were found between current blood Pb, historical blood Pb, zinc protoporphyrin (ZPP), and serum creatinine and urate. Blood pressure was not associated with Pb exposure. Among the urinary markers, only NAG showed a positive association with current and historical blood Pb. CONCLUSION: An exposure-response relation between Pb and renal dysfunction across the range from < 40 to > 70 micrograms/dl blood Pb was found in this workforce, with conventional measures of short and long term Pb exposure and of renal function. This could not be explained by an effect on blood pressure, which was not associated with Pb exposure. The findings probably reflect a higher cumulative renal burden of Pb absorption in this workforce in comparison with those in recent negative studies. The results also confirm the need for strategies to reduce Pb exposure among industrial workers in South Africa.

Acetylglucosaminidase↗
PubMed1986

Lead nephropathy.

In the past, lead poisoning was recognized when classical symptoms of acute intoxication were present and the blood lead was elevated. The EDTA test is presently the most reliable method for detecting excessive lead stores. We used the EDTA lead-mobilization test to demonstrate excessive past lead absorption as a cause of renal disease in lead workers and in both gouty and hypertensive patients with renal failure. These studies show that lead nephropathy occurs in the absence of acute intoxication and that occult poisoning often goes unrecognized because of inappropriate diagnostic criteria.

Adult↗
PubMed1984

Determination by flameless atomic absorption of aluminium in serum and hair for toxicological monitoring of patients on chronic intermittent haemodialysis.

Determination of aluminium in serum of patients on chronic intermittent haemodialysis is of paramount importance in the prevention or early diagnosis of aluminium intoxication. We present a new method based on flameless atomic absorption spectroscopy, in which the serum matrix is destroyed by oxygen. A comparison has been made between the described method and another procedure which is used in the Laboratory of Toxicology in Ghent, with favourable results. In addition, a method is presented for the determination of aluminium in hair, in which special attention has been paid to the cleaning of the hair samples prior to destruction. As yet it cannot be concluded whether aluminium concentrations in hair give a better representation of the body burden than serum levels do.

Aluminum↗
PubMed1984

Serum ferritin as a guide for iron stores in chronic hemodialysis patients.

The serum ferritin (SF) level was measured in 58 chronic hemodialysis (CHD) patients (46 living and 12 deceased subjects) and compared to bone marrow iron concentrations, cytological bone marrow iron stores (BMIS), and histological BMIS. In the 12 deceased subjects, liver iron concentrations, histological liver parenchymal, and Kupffer cell iron stores were also studied. The mean SF level of the whole group was 302 +/- 251 ng/ml (mean +/- SD). No close relationship was found between transferrin saturation and cytological BMIS. A high correlation was found between SF level and cytological BMIS (Spearman rank rs = 0.74). In the deceased CHD patients a close correlation was observed between histological parenchymal liver iron stores and histological Kupffer cell iron stores, but not between liver and bone marrow iron stores. A good correlation was found between SF levels and liver iron concentrations. It is concluded that in CHD patients SF levels are higher than in healthy controls, even in the absence of iron therapy (except in the form of blood transfusions); in some of these patients iron is disproportionately stored in the bone marrow and the liver. Although the level of BMIS cannot be estimated unequivocally from an SF measurement in every CHD patient, SF levels provide useful estimates of BMIS.

Adult↗
PubMed1984

Ultrastructural localization of aluminum in patients with dialysis-associated osteomalacia.

Using laser microprobe mass analysis, we studied the ultrastructural localization of aluminum in liver and bone tissue of chronic-hemodialysis patients with proven aluminum-induced osteomalacia. In the liver, aluminum was observed to be almost exclusively associated with iron. Detectable aluminum and large amounts of iron were found in lysosomes of both hepatocytes and Kupffer cells. In bone, aluminum was localized at the osteoid/calcified-bone interface and also was associated with iron in some cases.

Adult↗
PubMedDate not supplied

Urinary biomarkers as indicators of renal disease.

Using modern technology, minute quantities of LMWP, prostanoids, growth factors, intra-renal and extra-renal enzymes can be measured in urine. Excretory patterns that are characteristic for site and mechanism of renal injury often can be found. It is possible to recognise urinary biomarker patterns that suggest the putative environmental nephrotoxin. Our own studies performed in subjects with low level occupational and environmental exposures in New Jersey confirm the pattern specificity and threshold effects for Cr, Hg and Pb. In addition, we have been able to show that increased NAG and IAP excretion following Pb exposure correlates with current (blood Pb) but not with the cumulative Pb burden (bone Pb). The relatively specific characteristic patterns of biomarker excretion are lost as renal failure progresses. Moreover, renal injury that results in tubular proteinuria may not progress to renal failure. Nevertheless, urine biomarkers can help to establish acceptable levels and identify the need for long term surveillance to ascertain when clinical renal disease may result.

Adult↗