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Biomedical subjects

A Visser

Publications and source records attributed to A Visser.

At least 55 records · Page 3Linked to original sources
PubMed1998

Effects of flutter and PEP mask physiotherapy on symptoms and lung function in children with cystic fibrosis.

Recently, the flutter was introduced as a new device to improve sputum expectoration. Preliminary data suggested a significant improvement in expectoration and lung function during flutter treatment in patients with cystic fibrosis (CF). The aim of the present study was to compare the effects of the flutter and the positive expiratory pressure (PEP) mask on symptoms and lung function in children with CF. In a crossover randomized study 22 patients with CF (mean age 12 yrs, range 7-17 yrs) performed physiotherapy using either the flutter or the PEP mask twice a day during two treatment periods of 2 weeks, separated by a one week wash-out period, in a random sequence. Lung function parameters (peak expiratory flow, forced vital capacity (FVC), forced expiratory volume in one second, maximal midexpiratory flow, maximal expiratory flow at 25% of FVC, thoracic gas volume, total lung capacity, residual volume/total lung capacity, airway resistance and specific airway conductance) and changes in transcutaneous oxygen haemoglobin saturation were assessed before and after the first supervised session and at the end of each treatment period. Throughout the study peak flow was measured and symptoms were scored daily. No significant changes in any lung function parameter occurred after a single session or after 2 weeks of physiotherapy with either method. There was no difference in acceptability and subjective efficacy. In conclusion, any superiority of the flutter over the positive expiratory pressure mask technique for expectoration could not be confirmed during 2 weeks of daily treatment in children with cystic fibrosis. Both methods are well accepted by children and do not change lung function. Long-term comparison of both methods, including expectoration measurements, seems to be required for further evaluation of the potential success of physiotherapy in cystic fibrosis.

Adolescent↗
PubMed1998

[Syndromes 4. Sanfilippo syndrome].

The Sanfilippo syndrome belongs to the mucopolysaccharidoses. In this syndrome heparansulfate accumulates in the lysosomes because of an enzymatic disorder in the degradation of mucopolysaccharides. The result is a function disorder of the involved tissues. The Sanfilippo syndrome is characterized by a combination of mental deterioration from the third year of life, hepatosplenomegaly and a typical facial appearance. These characteristics and the implications for dental treatment are discussed.

Craniofacial Abnormalities↗
PubMed1997

[Harlequin syndrome].

Harlequin syndrome is an autonomic syndrome of heat, emotion and exercise induced flushing and sweating limited to one side of the face in combination with impairment of sweating and flushing on the contralateral side, Two women aged 32 and 39 years displayed this syndrome. In one patient no other neurological symptoms were found; MRI of cervicothoracic spine failed to disclose a structural lesion. The second patient had four years before presented with a Horner's syndrome on the contralateral side, where MRI now disclosed a tumour located in the paravertebral thoracic region at the apex of the lung.

Adult↗
PubMed1997

Determination of the anti-factor Xa activity of the synthetic pentasaccharide SR 90107A/ORG 31540 and of two structural analogues.

The anti-factor Xa activity of the synthetic pentasaccharide SR 90107A/ORG 31540 was assayed by a chromogenic method at pH 8.4 and pH 7.35, comparatively to the 4th International Heparin Standard (IHS) or to the Ist International Low Molecular Weight Heparin Standard (LMWHS). At pH 8.4, SR 90107A/ORG 31540 was found to have a specific anti-factor Xa activity of 639 +/- 14 and 659 +/- 19 IU/mg (mean +/- sem, n = 6) when assayed in comparison with the 4th ISH and the Ist LMWHS respectively. At pH 7.35, the corresponding figures were 864 +/- 6 and 1160 +/- 51 IU/mg (mean +/- sem, n = 6) respectively. The dissociation constants of the ATIII-pentasaccharide complex formed by SR 90107A/ORG 31540 and by two close analogues: SR 80327A and SR 80027A in the presence of purified human ATIII were found to be 41 +/- 8, 96 +/- 1 and 3 +/- 1.4 nM (mean +/- sem, n = 3) respectively. For the three compounds, the pseudo-first order molar catalytic constants for factor Xa inactivation by the ATIII-pentasaccharide complex were shown to be statistically comparable, in the range of 7-8 x 10(7) min-1 per mole. It is concluded that the differences in specific anti-factor Xa activities between SR 90107A/ORG 31540 and its synthetic chemical analogues can be attributed to variations of the dissociation constants whereas the catalytic constants for factor Xa inactivation remain unchanged.

Factor Xa Inhibitors↗
PubMed1997

Protective immune responses to Theileria annulata of relevance to vaccine development.

A series of projects on Theileria annulata funded by the European Union (STD1/STD2/STD3) have provided convincing evidence that macrophage and natural killer (NK) cell-dependent immune mechanisms may directly control the proliferation of different stages of T. annulata in cattle. The evidence for this conclusion and the implications for vaccine development are discussed in the following paper.

Animals↗
PubMed1997

Effectiveness of a short-term group psychotherapy program on endocrine and immune function in breast cancer patients: an exploratory study.

Cancer patients who had been treated for early stage breast cancer and were diagnosed with either positive axillary lymph nodes or distant metastases were randomly assigned to either a 13-week experiential-existential group psychotherapy (EEGP) program or a waiting list control (WLC) condition. Endocrine and immune measures were obtained before and after the intervention period. The findings of this study are that, after the 13 weeks of the experiment, patients in the EEGP group showed lower levels of plasma cortisol and lower levels of prolactin as well as lower percentages of natural killer cells, CD8 cells, and CD4 cells in addition to a lower proliferative response to pokeweed mitogen than patients in the WLC group. Importantly, this was only found in those breast cancer patients presenting relatively high endocrine and immune baseline levels, suggesting that the patients' profile with regard to endocrine and immune function at the start of a program can have an important effect. If replicated on a larger scale, the current results may be relevant for the treatment of breast cancer.

Adrenocorticotropic Hormone↗
PubMed1997

Characterization of an acetylcholine receptor gene of Haemonchus contortus in relation to levamisole resistance.

The anthelminitic drug levamisole is thought to bind to nicotinic acetylcholine receptors of nematodes. It is possible that resistance to this drug is associated with either a change in binding characteristics or a reduction in the number of nicotinic acetylcholine receptors. Therefore, the molecular mechanism of levamisole resistance in the parasitic nematode Haemonchus contortus was studied by isolating and characterising cDNA clones encoding a putative ligand binding nicotinic acetylcholine receptor subunit, HCAl, of two susceptible and one levamisole resistant population. Hcal is related to unc-38, a nicotinic acetylcholine receptor subunit gene associated with levamisole resistance in Caenorhabditis elegans. Although extensive sequence analyses of hcal sequences revealed polymorphism at amino acid level, no association with levamisole resistance could be detected. Restriction fragment length polymorphism analyses confirmed that, although polymorphism was detected, no selection of a specific allele of hcal has taken place during selection for levamisole resistance in various levamisole resistant populations.

Amino Acid Sequence↗
PubMed1997

Health communication research.

In this special issue on health communication research, nine studies are presented on the following subjects: effectiveness of health education and promotion, an instrument for reviewing the effectiveness of health education and promotion, consumer awareness of health mass media campaigns, health counseling by primary health care personnel, cues to action in the process of changing lifestyle, perception of anti-smoking advertisement, reactions facing threat of nuclear accidents, the role of medical journalists, and the results of a multi-media course on urinary incontinency. The main focus is an effectiveness analysis, audiences studies and communication analysis in the broad field of health communication research. Several methodological issues are raised. Applications in the field of clinical health promotion, and patient education and counseling are stressed.

Health Education↗
PubMed1996

Adjustment to breast cancer: the psychobiological effects of psychosocial interventions.

This review focuses on the effects of psychosocial interventions on psychological and biological functioning of breast cancer patients. Once in their lifetime, one out of eleven women receive a diagnosis of breast cancer. A diagnosis of breast cancer is a severe stressful life event with profound consequences on all aspects of human life. Whether a woman will regain emotional balance and accept the idea of living with a potentially life threatening disease depends on her psychological resiliency. Provision of psychosocial interventions can improve these women's coping abilities and reduce emotional distress and feelings of isolation, and improve psychosexual functioning. Additionally, there exists some evidence that psychotherapy may prolong survival. Prolongation of survival may be related, in part, to an increase in certain aspects of immune function (e.g., natural killer cell activity). This is plausible because the function of the immune system seems to be related to mammary tumor growth. Therefore, future research should examine the degree to which the effects on mammary tumor growth relate to immune system changes.

Adaptation, Psychological↗
PubMed1995

Peptide-derived transition state analogue inhibitors of thrombin; synthesis, activity and selectivity.

In a study to combine the transition state analogue concept with the principle of catalytic site spanning, a series of peptide-derived transition state analogue (TSA) inhibitors of thrombin has been synthesized and tested. In the sequence H-D-Phe-Pro-Arg-Gly-OH (2) the Arg-Gly amide bond has been replaced by three classes of transition state analogues, being the ketomethylene, the hydroxyethylene and the hydroxymethylene amide bond replacements. Compound 12a, in which the amide bond has been replaced by the ketomethylene group, was found to be the most potent thrombin inhibitor of the series studied. Subsequently, penta- and hexapeptide sequences with good affinity for thrombin were developed, i.e. H-D-Phe-Pro-Arg-Gly-Phe-OH (16) and H-D-Phe-Pro-Arg-Gly-Phe-Lys-OH (26). In these sequences the Arg-Gly amide bond was then replaced by the ketomethylene group. The resulting compounds 43a and 47a, respectively, were evaluated in vitro as inhibitors of thrombin and factor Xa. Compound 47a was found to be the most potent thrombin inhibitor of the series studied (Ki = 29 nM). The combination of the transition state analogue concept and the principle of peptide elongation (tetrapeptide-->hexapeptide) yields thrombin inhibitors of high potency and selectivity. The effects of these two alterations reinforce each other indicating a synergistic effect. This might be rationalized by entropy factors.

Amino Acid Sequence↗
PubMed1995

The temporal/masseter co-contraction: an electromyographic and clinical evaluation of short-term stabilization splint therapy in myogenous CMD patients.

The short-term effect (3-6 weeks) of the use of a stabilization splint was investigated in a group of 35 myogenous craniomandibular disorder patients. The patients were clinically examined and surface EMG recordings of the temporal and masseter muscles were made during clenching in the intercuspal position (ICP), immediately after the insertion of the splint (SSP), and after at least 3 weeks of splint treatment (SSP 3). With the use of the error variance of the activity index changes in EMG activity were investigated. Three groups of patients were then recognized. One group showed a decrease in temporal muscle activity during splint treatment. Another group did not show any significant change during splint treatment. The third group showed an increase of temporal muscle activity. In general, significant reductions in the amount of static pain were found. In the group with a significant reduction of temporal muscle activity (n = 15) there was a greater decrease in the amount of static pain (P < 0.05) than in the group (n = 4) with a significant increase of temporal muscle activity. The results may indicate that the temporal muscle plays an important role in the perception of static pain in the masticatory system.

Adolescent↗
PubMed1995

EMG differences between weak and strong myogenous CMD patients and healthy controls.

Electromyographic and clinical characteristics of 42 myogenous craniomandibular disorder (CMD) patients were related to 40 healthy control subjects. Surface EMG recordings were obtained from the masseter and the temporal muscles. The clinical examination included active maximum mouth opening, endfeel distance, active laterotrusion and lateral endfeel distance, dental abrasion, the presence of a lateral slide (RCP-ICP) and the amount of static pain. Orthopantomographic X-rays were available from 32 CMD patients for measuring the condylar and ramus asymmetry. Compared to the control group lower masseter and temporal EMG amplitudes were found for myogenous CMD patients (P < 0.001). When the activity of the temporal muscle was compared with the activity of the masseter muscle, the CMD patients showed proportionally higher temporal muscle activities than the controls (P < 0.05, 50% clenching level). CMD patients also showed smaller mandibular excursions, larger endfeel distances and more dental abrasion than controls. The temporal muscle asymmetries showed significant negative correlations with the ramus asymmetries. The lower and upper quartile of the distribution of the mean masseter EMG amplitudes were used to distinguish weak and strong muscles in patients and controls. Weak patients showed proportionally high temporal muscle activities, larger masseter and temporal muscle asymmetries, and larger endfeel distances compared to strong CMD patients. These differences were not found between weak and strong controls. In conclusion, it can be said that the electromyographic and clinical findings of the myogenous CMD patients suggest a functional difference between weak and strong patients and indicate the need for more individually designed treatment modalities for functional muscle and joint CMD problems.

Adolescent↗
PubMed1995

Synthetic analogues of the antithrombin III-binding pentasaccharide sequence of heparin. Prediction of in vivo residence times.

The synthetic pentasaccharide Org 31540/SR 90107A represents the antithrombin III (ATIII) binding region of heparin and accelerates the ATIII-mediated inhibition of coagulation factor Xa. This compound and 15 structural analogues with ATIII binding constants (Kd) ranging from 2.7 to 2600 nmol/L were compared for their plasma elimination in rats as measured from their factor Xa inhibiting activity. After administration of a low dose (100 nmol/kg body wt IV), each pentasaccharide showed a characteristic plasma half-life varying from a minimum of 0.3 hour for pentasaccharides with low affinity for ATIII to 10.9 hours for pentasaccharides with high affinity for the protein. The latter value was close to the half-life measured for radioiodinated rat ATIII (11.8 hours). We hypothesized that the elimination half-life of pentasaccharides is markedly extended by ATIII binding, of which the extent is governed by the Kd of the complex. The following observations support this hypothesis. The low-dose, low-affinity pentasaccharides were almost fully recovered in the urine without having lost anti-factor Xa activity, whereas compounds with high ATIII binding affinity were only partly recovered in the urine. With a high dose (500 nmol/kg body wt), a rapid plasma clearance of pentasaccharide was observed until a concentration similar to that of endogenous ATIII was reached, in accordance with their expected 1:1 stoichiometric interaction. The elimination of half-life was similar to that of the low dose. The relation between Kd values and plasma half-lives could be explained by assuming rapid clearance of free and coclearance of ATIII-bound pentasaccharide with the protein.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Parental management of infants born following a cot-death victim who were monitored compared to infants who, despite similar histories, were not monitored: a controlled study.

We studied 93 families who had previously lost a baby to cot-death. Of these, 31 chose cardiorespiratory monitoring (CRM) for their next child and were compared to 62 families who, despite similar histories, decided not to monitor their subsequent infant. A control group consisted of 50 families without history of cot death. The three objectives of this retrospective study were: (1) to gain insight into psychological factors which differentiate between parents who insist on monitoring their infant and those who do not; (2) to explore how parents of both groups cope with their feelings of anxiety and stress and; (3) to examine the effect of psychological factors on parental reactions to monitor alarms. Infants of the monitor group and the nonmonitor group were matched to the age reached by the previous cot-death victims at the moment of death. Parents who had experienced cot-death (91%) and 37% of the control group parents completed the State-Trait Anxiety Inventory (STAI) and a questionnaire, consisting mainly of multiple-choice questions. Results show that monitor parents and nonmonitor parents differ greatly in their expectations of and attributions to the equipment and in the way they process information about monitoring. More monitor parents attribute a protective value to CRM. Monitor parents reported to have been more stressed during pregnancy. Postnatally, monitor parents and nonmonitor parents did not experience different anxiety levels. Nonmonitor parents experienced a slight decrease of feelings of happiness over time. Mothers with high state anxiety scores noted more false bradycardia alarms than mothers with low scores.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗