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Biomedical subjects

A M Vermeulen

Publications and source records attributed to A M Vermeulen.

At least 19 recordsLinked to original sources
PubMed1999

Allergy to bumblebee venom. III. Immunotherapy follow-up study (safety and efficacy) in patients with occupational bumblebee-venom anaphylaxis.

BACKGROUND: The objective was to investigate whether venom immunotherapy with bumblebee venom (BBV) is safe and effective. METHODS: Eleven patients with severe occupational anaphylaxis caused by stings of bumblebees were studied. Sensitization to bumblebee venom was confirmed by skin tests and RAST. Immunotherapy was started with bumblebee venom extract by the semirush procedure, because these patients showed a primary sensitization to Bombus venom, and a low or absent degree of cross-reactivity with honeybee venom. IgE titer and skin tests with bumblebee venom were performed yearly. Efficacy was evaluated by means of in-hospital sting challenge and/or occupational field stings from bumblebees. RESULTS: All patients reached maintenance dose in 6 weeks without severe side-effects. During the follow-up period (1.5-5 years), three systemic reactions in two patients were seen in 20 bumblebee stings. However, these reactions were milder than the index sting. CONCLUSIONS: Immunotherapy with bumblebee venom is safe and effective, and is comparable with honeybee and yellow-jacket venom immunotherapy.

Adult↗
PubMed1998

Assessment of basal sound identification skills and communication abilities in profoundly deaf children fitted with hearing aids or a cochlear implant.

Basal auditory functions and early verbal communication skills were examined in young, profoundly deaf children with hearing aids or a cochlear implant. The hearing aid users (n = 23) were subdivided on the basis of their (unaided) hearing thresholds into: group A (pure tone average (PTA) at 0.5, 1 and 2 kHz: 90-100 dB HL); group B (PTA: 100-110 dB HL); and group C (PTA > 110 dB HL). All the children with a cochlear implant (n = 20) had a profound sensorineural hearing loss with a PTA that exceeded 120 dB HL. Functional hearing was evaluated by means of basal sound identification. The child's communication abilities with hearing aids or a cochlear implant were assessed using structured observations on the Scales of Early Communication Skills for Hearing Impaired Children. The basal auditory functions on a sound identification level improved over time in the cochlear implant users and groups A and B. Hardly any improvement was seen in group C. The performance of all the groups (either hearing aid or cochlear implant) on the Scales of Early Communication Skills for Hearing Impaired Children at 6 months after fitting the device and at later evaluations, was close to the average level for their age.

Audiometry, Pure-Tone↗
PubMed1998

Occupational allergy caused by flowers.

We describe 14 consecutive patients with complaints due to the handling of flowers. The symptoms varied from allergic rhinoconjunctivitis and asthma to urticaria. Most patients had professions in the flower industry. Skin prick tests (SPT) were performed with home-made pollen extracts from 17 different flowers known to be the most commonly grown and sold in The Netherlands RAST against mugwort, chrysanthemum, and solidago was performed. The diagnosis of atopy against flowers was based on work-related symptoms due to the handling of flowers, positive SPT with flower extracts, and positive RAST. The concordance between SPT and case history was 74%, and that between SPT and RAST was 77% Extensive cross-sensitization was seen to pollen of several members of the Compositae family (e.g., Matricaria, chrysanthemum, solidago) and to pollen of the Amaryllidaceae family (Alstroemeria and Narcissus). Homemade flower extracts can be used to confirm IgE-mediated flower allergy. Mugwort can be used as a screening test for possible flower allergy. For most patients, the allergy led to a change of profession.

Adult↗
PubMed1997

The relation between age at the time of cochlear implantation and long-term speech perception abilities in congenitally deaf subjects.

The issue of whether an upper age limit should be set for cochlear implantation in congenitally deaf subjects has often been debated. To gain more insight, the speech perception abilities were analyzed of 12 congenitally deaf subjects whose age at the time of cochlear implantation ranged from 4 to 33 years. Subjects implanted during adulthood only showed progress during the first few months after the speech processor had been fitted and their long-term results were poor compared to those of children implanted early in life. This latter group showed steady improvement over the whole evaluation period. The present results support the notion that the earlier in life implantation is performed, the better the development of speech perception. Based on the progress-over-time profiles and data on actual daily use of the cochlear implant, it can be suggested that implantation of congenitally deaf subjects during or after puberty offers only limited benefit.

Adolescent↗
PubMed1997

Speech perception performance of children with a cochlear implant compared to that of children with conventional hearing aids. I. The "equivalent hearing loss" concept.

A new measure has been developed to quantify the speech perception performance of children with a cochlear implant (CI). The method summarizes the speech perception scores obtained on a battery of tests that ranges from very basal tasks up to open speech recognition. The overall performance of a child with a CI on the test battery at a certain time during follow-up is matched to that of a reference group of severely and profoundly hearing-impaired children with conventional hearing aids. This matching procedure results in the expression of the speech perception scores of a child with a CI as an "equivalent hearing loss" value. The equivalent hearing loss concept deals adequately with floor and ceiling effects which inevitably occur when a battery with such a large range of tests is used. To illustrate this, application of the procedure to three children with a CI showed that before implantation, while they were using conventional hearing aids, the equivalent hearing loss was above 120 dB hearing level (HL). At 3 years' follow-up the equivalent hearing loss improved to 70 dB HL in the two children with an aetiology of meningitis. This means that these children were performing as well as children in the reference group with a hearing loss of 70 dB HL. The child with congenital deafness showed minor improvements over time.

Child↗
PubMed1997

Speech perception performance of children with a cochlear implant compared to that of children with conventional hearing aids. II. Results of prelingually deaf children.

In a previous paper, a method was introduced to transform the results obtained by children with a cochlear implant (CI) on a battery of speech perception tests into an overall value, the "equivalent hearing loss" value. This was achieved by matching the speech perception test scores with those of a reference group of children with conventional hearing aids and hearing loss ranging from 50 to 130 dB hearing level (HL). The equivalent hearing loss values of 16 prelingually deaf children with a CI were plotted as a function of time. There was considerable spread in the rate of progress made by the children in terms of the equivalent hearing loss values. The variables studied, age at onset of deafness/duration of deafness (in the present study, these two factors were indistinguishable) and the communication mode used at the children's school, accounted for 64% of the variance in speech perception performance. A plateau in the performance of the better performers was found which seemed to be caused by the level of hearing (the aided thresholds) with the CI.

Age of Onset↗
PubMed1997

Long-term speech perception in children with cochlear implants compared with children with conventional hearing aids.

OBJECTIVE: To determine the speech perception of children with cochlear implants. SUBJECTS AND METHODS: Speech perception results of seven children with cochlear implants (excellent performers), who showed stable speech recognition scores in the long term, were compared with those of severely hearing-impaired children with conventional hearing aids (reference group). The groups of children were matched according to their mean free-field aided thresholds. RESULTS: The results of the open-set word recognition test were comparable in the two groups. CONCLUSION: If we consider the results of the hearing aid users as the gold standard, the results suggest that speech recognition in selected children with a cochlear implant is close to optimal.

Audiometry, Pure-Tone↗
PubMed1997

Speech perception performance of congenitally deaf patients with a cochlear implant: the effect of age at implantation.

The relation between age at cochlear implantation and long-term open-set speech recognition was studied in a group of nine congenitally deaf children. The age at cochlear implant surgery ranged from 4 to 13 years. The results showed that there was a tendency toward poorer results in the children implanted at a relatively older age. However, the results also indicated that an upper limit for age at implantation cannot yet be defined in these children.

Adolescent↗
PubMed1996

Sustained decrease of serum total IgE in cardiac transplant recipients.

A steady decrease in serum IgE was noted in cardiac transplant recipients receiving a combination of cyclosporin A and prednisolone for immunosuppressive therapy. The average time period for the demonstration of a 50% decrease in serum IgE levels was calculated to be 40 +/- 16 days in 19 patients.

Cyclosporine↗
PubMed1994

The effect of different calcium antagonists and a calcium agonist on the metabolism of propranolol by isolated rat hepatocytes.

The influence of the dihydropyridine calcium entry blockers nicardipine, amlodipine, nifedipine, isradipine and of the dihydropyridine calcium entry promotor BAY K 8644 on the disappearance rate of propranolol by isolated rat hepatocytes was compared to the effect of diltiazem and verapamil, two non-dihydropyridine calcium channel blockers and known inhibitors of hepatic cytochrome P450 mixed function oxidases. All compounds dose-dependently inhibited the disappearance rate of propranolol. Nicardipine and isradipine were more potent in inhibiting the disappearance rate of propranolol than the other dihydropyridines and than diltiazem and verapamil. The inhibitory effect of nicardipine on the disappearance rate of propranolol was not stereoselective and was not influenced by age.

Aging↗
PubMed1993

Influence of human recombinant interleukin-1 beta on the enantioselective disposition of propranolol in rats.

The influence of i.v. administration of 10 micrograms/kg recombinant human interleukin-1 beta (rhIL-1 beta), a putative mediator of inflammation, on the pharmacokinetics and metabolism of the propranolol enantiomers was studied in rats aged 3, 12 and 24 months. After oral administration of rac-propranolol to control rats of the three age groups, the plasma concentrations of (R)-propranolol were higher than those of (S)-propranolol. Administration of IL-1 beta increased the plasma concentrations of the (R)-enantiomer markedly and significantly, those of the (S)-enantiomer only to a lesser degree. For both enantiomers an important increase in plasma binding was found in the IL-1 beta-treated rats, which was linked to the increase in alpha 1-acid glycoprotein levels. The in vitro clearance, measured in 3-month-old rats using the 9000 g liver fraction, was for neither of the propranolol enantiomers influenced by IL-1 beta treatment, which is in keeping with the unchanged cytochrome P450 content. The enantioselective influence of IL-1 beta treatment on the pharmacokinetics of propranolol was also present in 12- and 24-month-old rats, although somewhat less pronounced in the latter group. Our results show an enantioselective influence of IL-1 beta treatment on the pharmacokinetics of propranolol in the rat, favouring the (R)-enantiomer.

Aging↗
PubMed1993

Stereoselective pharmacokinetics of atenolol in the rat: influence of aging and of renal failure.

The pharmacokinetics of R- and S-atenolol after intravenous administration of racemic atenolol were studied in 3-, 12- and 24-month-old rats and in 3-month-old rats with renal failure induced by uranyl nitrate. In all age groups, the area under the plasma concentration-time curves is higher for R- than for S-atenolol; volume of distribution, total clearance and renal clearance are lower for R-atenolol than for S-atenolol, but the differences are small. In function of age there is for both enantiomers a significant increase in AUC, due, at least in part, to a decreased renal clearance; the effect of aging is not stereoselective. In rats with renal failure, the AUC of both enantiomers increases, due mainly to a decrease in renal clearance, but to a lesser degree also to a decrease in nonrenal clearance. For both enantiomers, the volume of distribution decreases and the half-life increases in the uraemic rats. The total amount of both enantiomers excreted in the urine is decreased in the rats with renal failure. There are no stereoselective effects of treatment of the rats with uranyl nitrate.

Aging↗
PubMed1993

Aging and the pharmacokinetics and metabolism of metoprolol enantiomers in the rat.

After i.v. administration of racemic metoprolol in the rat, the plasma concentrations of (R)- and (S)-metoprolol were comparable, and no differences in pharmacokinetic parameters between the two enantiomers were found. From the 3rd to the 12th month, comparable changes were seen for both enantiomers: there was an increase in the area under the plasma concentration-time curve (AUC) and a decrease in blood and plasma clearance. Half-life showed a significant prolongation, volume of distribution decreased between 3 and 12 months and increased between 12 and 24 months. After oral administration of the racemate, AUC and Cmax (maximum plasma concentration) were slightly higher, while oral clearance was slightly lower for (R)-metoprolol than for (S)-metoprolol. With aging, Cmax and AUC increased for both enantiomers, while oral clearance decreased. The change in oral clearance as a function of age is different between (S)- and (R)-metoprolol, and thus enantioselective. In vitro disappearance rate in 3-month-old rats was significantly higher for (S)-metoprolol than for (R)-metoprolol, although the difference was small. With aging, the disappearance rates of both enantiomers increased significantly, but not enantioselectively.

Administration, Oral↗