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J W Louwerens

Publications and source records attributed to J W Louwerens.

16 recordsLinked to original sources
PubMed2001

Assessing the subtalar joint: the Brodén view revisited.

We prospectively evaluated subtalar inversion stress views (Brodén view) with inversion stress views on helical CT in a group of 10 patients with unilateral instability. The contralateral, asymptomatic ankle was used as control. All patients were examined with inversion stress views on plain stress radiography and helical CT. Subtalar tilt was demonstrated in all cases on conventional stress radiography. Helical CT didn't show tilting in any of the patients except in the subluxated posteromedial part of the subtalar joint. Our data do not support prior reports that the Brodén view is useful for screening patients with subtalar instability.

Adolescent↗
PubMed2000

Posttraumatic subchondral bone contusions and fractures of the talotibial joint: occurrence of "kissing" lesions.

OBJECTIVE: The objective of this study was to determine the presence and location of subchondral bone contusions, fractures, and "kissing" lesions of the talotibial joint after a sprain of the ankle shown on MR imaging. MATERIALS AND METHODS: We retrospectively reviewed the images of all consecutive patients who underwent MR imaging of the ankle after acute or recurrent sprain occurring between January and December 1997. The number and location of subchondral contusions or fractures revealed on MR imaging were recorded, and a comparison was made with the radiographs obtained for each patient. RESULTS: Of the 146 ankles, 42 osteochondral lesions were revealed on MR imaging in 26 ankles (18%) involving 23 patients. Twenty-three lesions were localized in the dome of the talus and 19, in the tibiofibular plafond. In 16 (11%) of the 146 ankles, the lesions were present in the opposing bones of the joint ("kissing" lesions). Only six of the 12 talar fractures and none of the tibial fractures involving the 26 ankles were seen on conventional radiography. CONCLUSION: Subchondral lesions in the talus and tibia are relatively common after ankle trauma, occurring in 18% of patients in our series. Kissing lesions were present in more than half of the lesions in these patients.

Adult↗
PubMed1999

Psychomotor, Cognitive, extrapyramidal, and affective functions of healthy volunteers during treatment with an atypical (amisulpride) and a classic (haloperidol) antipsychotic.

The primary objective of this study was to compare the objective and subjective effects of amisulpride with those of a classic antipsychotic, haloperidol, when both were given to healthy volunteers in representative therapeutic doses over 5 days. The secondary objective was to compare the effects of relatively low and high doses of amisulpride to confirm the suspected duality of its pharmacologic activity. Twenty-one subjects participated in the four-way, randomized, double-blind, crossover study with repeated daily doses of amisulpride 50 mg, amisulpride 400 mg, haloperidol 4 mg, and placebo. Subjects were institutionalized during treatment periods and were under 24-hour medical supervision. They underwent a series of psychomotor and cognitive tests 1 hour before and 3 and 6 hours after dosing on days 1 and 5. Their extrapyramidal disturbances and drug-related feelings were assessed at the end of each replication. Psychiatric interviews and ratings of depression, subjective well-being, and negative symptoms occurred on day 4. Amisulpride 50 mg had no significant effect on any parameter. Amisulpride 400 mg had several adverse effects on psychomotor and, although less severe, on cognitive performance on the fifth day only. Amisulpride 400 mg produced no significant extrapyramidal disturbances in the group as a whole, although it may have in some individual subjects. Also, it produced no signs of mental disturbances on clinical rating scales or during a structured psychiatric interview. Haloperidol ubiquitously impaired psychomotor and cognitive performance in a similar fashion after the first and the final doses. It produced extrapyramidal disturbances in nearly every subject, the most common being akathisia and the most severe, in the case of one individual, being acute dystonia. Unlike amisulpride, haloperidol produced a number of mental disturbances, the most noteworthy being negative symptoms. Amisulpride seems to be a well-tolerated drug. Its side effects should be much less troublesome to patients using the drug on a long-term basis than those of classic antipsychotics, like haloperidol.

Adult↗
PubMed1997

Stress radiography and stress examination of the talocrural and subtalar joint on helical computed tomography.

The main objective of this study was to compare subtalar inversion stress views using the Brodén view with inversion stress views on helical computed tomography (CT). One of the drawbacks of routine radiography is the imaging of three-dimensional structures in a two-dimensional plane. We investigated whether the use of helical CT would lead to a more objective and clearer measurable method to determine the amount of tilt in the subtalar joint. A group of 15 patients with unilateral chronic instability complaints and clinically suspected subtalar instability was examined. The contralateral asymptomatic foot was used as control. A variable amount of subtalar tilt (range, 4 degrees to 18 degrees) was demonstrated in all cases on stress radiographs, without finding significant difference between the symptomatic and asymptomatic feet. However, contrary to the findings at the talocrural level, subtalar tilt was found in none of the patients using helical CT. Thus, we now doubt that the tilt seen during stress examination using the Brodén view is the true amount of tilt. It may be that the lateral opening, seen on these radiographs, largely results from imaging two planes that have made a translatory and rotary movement relative to each other in an oblique direction. It is concluded that the Brodén stress examination might not be useful for screening patients with subtalar instability. Associated anomalies not visible on the radiographs were detected by helical CT. In four cases, narrowing of the articular cartilage and irregular and hypertrophic bone formation at the middle facet joint of the subtalar joints were found. It is likely that these changes cause disturbance of function of this joint and it is suggested that the subjective complaint of instability with "giving way" is not only caused by hypermobility, but can be caused by other disturbance of normal motion.

Adolescent↗
PubMed1996

Expressed emotion on long-stay wards.

We examined the influence of an educational programme on nurses' level of expressed emotion (EE), on ward climate and on social functioning and psychopathology of hospitalized schizophrenic patients. Nurses and patients were from long-stay wards of six Dutch psychiatric hospitals. Despite an increase of nurses' knowledge about schizophrenia we did not find measurable effects on nurses' levels of EE. According to the five minute speech sample method, a third of the nurses participating in this study had a high level of expressed emotion, mainly consisting of criticism. This was a rather stable pattern. Patients, however, were reluctant to give their nurses high EE ratings on the level of expressed emotion scale. Psychopathology was not influenced by the educational programme, but social functioning of patients was related to EE in nurses. Moreover, we found a significant decline in the number of restrictive ward rules at follow-up. We conclude that, while it may be difficult to detect changes in EE level after an educational programme for nurses, there nevertheless appear to be measurable benefits for patients.

Adult↗
PubMed1995

Differential effects of the D1-DA receptor antagonist SCH39166 on positive and negative symptoms of schizophrenia.

In the present open study the effects of the D1-dopamine antagonist SCH 39166 on positive and negative symptoms of schizophrenia (DSM-IIIR) were investigated. SCH 39166 was given orally according to a fixed dosage schedule (day 1: 25 mg b.i.d; day 4: 50 mg b.i.d.; day 7: 100 mg b.i.d.; day 18: 200 mg b.i.d.; day 21: 225 mg b.i.d.). Seven patients completed 2 weeks, and five patients completed the study. The reason for premature withdrawal was lack of efficacy or refusal to take SCH 39166. In none of the patients a reduction of the BPRS or CGI score was found. As measured with the PANSS, a significant reduction was observed in the score of the negative subscale, whereas the positive symptoms scale and general psychopathology score remained unaffected. Akathisia, rigidity and hypokinesia were reported occasionally, although only mild in severity. The results of the present study do not support the hypothesis that D1-dopamine antagonists are clinically effective antipsychotics in schizophrenia, considering the fact that SCH 39166 had no effect on positive symptoms. The present study provides circumstantial evidence for an effect of SCH 39166 on negative symptoms.

Administration, Oral↗
PubMed1995

Stress radiography of the talocrural and subtalar joints.

The object of this investigation was to determine a possible subtalar component in a group of 33 patients with chronic ankle instability. A group of 10 subjects without ankle/foot symptoms acted as controls. A standardized radiographic assessment of talar and simultaneous subtalar tilt was made. A hinge device to stress the joints and a specific subtalar stress view (Brodén view) were used under fluoroscopic control. Radiographs were made with the feet: (1) in neutral position, (2) after inversion with moderate force until the point of fair restraint (step 1), and (3) after inverting with more force as far as the conditions would allow (step 2). An increase of talar tilt between step 1 and step 2 was only found in feet that were symptomatic. This suggests that this increase is only possible when lateral ligaments are damaged. Further research is necessary to determine whether this finding can serve as a parameter to discriminate between physiological and abnormal talar tilt. A wide range of subtalar motion was found in both symptomatic and asymptomatic feet. With the present method, practically all subtalar joints showed some loss of congruity and medial shift of the calcaneus in relation to the talus. This could not be correlated with ankle instability at the talocrural joint. The consequence of the use of different subtalar stress methods has so far received little attention and is discussed.

Adolescent↗
PubMed1995

Peroneus longus and tibialis anterior muscle activity in the stance phase. A quantified electromyographic study of 10 controls and 25 patients with chronic ankle instability.

The electromyographic activity of the peroneus longus and anterior tibial muscles of 25 patients with chronic ankle instability (18 patients with bilateral symptoms and 7 patients with unilateral complaints) and 10 controls was registered during the stance phase under different walking conditions. With balance secured by external support, there was a variable amount of peroneal activity, most of which was found in the third quarter of stance. A high increase in peroneus longus activity starting after foot-flat was found when subjects had to maintain balance in a natural way. No difference in peroneal activity was found in relation to instability complaints. It is thought that the peroneus longus serves to maintain balance, that this function decreases with increase of speed and that one cannot rely on this muscle to prevent an inversion injury during normal walking. The anterior tibial muscle was predominantly active in the first quarter after heel contact. An increase in activity in the second quarter as an effect of loss of secured balance suggests that this muscle plays some part in balance control, but this is not its main function. A significant increase in tibialis anterior activity was found in patients with bilateral instability. No significant difference was found between the symptomatic and asymptomatic leg of patients with unilateral instability under the same walking conditions. These findings suggest changes in central control.

Adult↗
PubMed1993

Testing the effects of hypnotics on memory via the telephone: fact or fiction?

The two benzodiazapines used in this experiment, namely midazolam and flunitrazepam, have both been shown to have effects on memory processing in laboratory studies. In spite of the potential hazards involved in real life testing, it should be possible to replicate such findings in everyday environments and it is argued that a successful replication would be a very meaningful extension to the existing laboratory data. The present study was successful in producing significant "hangover" effects in healthy volunteers using a novel "user-friendly" telephone testing technique. Compared to placebo, the two hypnotics reduced speed of processing in tasks which required retrieval from long-term semantic memory (semantic verification) and the manipulation of material in working memory (syntactic reasoning). We suggest that this new method offers the potential for carrying out large-scale psychopharmacological studies with real patients and achieves a meaningful step forward in the search for ecological validity.

Adult↗
PubMed1992

Specific skills and social competence in schizophrenia.

Generalization of skills is a major problem in social skills training for schizophrenic patients. Assessment of skills is mostly not based on objective indices of specific skill deficits. The results of this study show that global competence of schizophrenics can be differentiated from specific competence. Global competence was found to be related to symptoms, whereas specific competence was not. No support was found for the assumption that social dysfunctions are caused by negative symptoms. Social perception and positive symptoms did explain a substantial part of the variance of global competence. It is therefore concluded that neither global incompetence nor negative symptoms should be used as an indication for social skills training.

Activities of Daily Living↗
PubMed1984

Immunocytochemical localization of neuroendocrine hormones and oncofetal antigens in ovarian teratomas.

The presence of neurohormonal peptides, human chorionic gonadotropin (hCG), alpha-fetoprotein (AFP), and carcinoembryonic antigen (CEA) was evaluated using immunocytochemical techniques in 170 benign cystic teratomas and 19 solid teratomas. The latter ranged from grade 0 to 3. The presence of hCG, AFP, and CEA was associated with a high histological grade and may therefore play a role in the grading of solid teratomas. Gastroenteropancreatic neuroendocrine cells frequently occurred in cystic teratomas without coexisting neural tissue. This finding is contrary to the neural crest origin previously suggested by other investigators and is in accordance with an endodermal origin of these cells.

APUD Cells↗
PubMed1982

Non-opiate beta-endorphin fragments and dopamine--I. The neuroleptic-like gamma-endorphin fragments interfere with the behavioural effects elicited by small doses of apomorphine.

In rats, the beta-endorphin fragment, 6-17 (des-enkephalin-gamma-endorphin, DE gamma E), dose-dependently antagonized the reduction of the rate of locomotion and rearing induced by small doses of apomorphine. Structure-activity studies revealed that the active moiety of gamma-endorphin fragments with respect to counteracting apomorphine-induced behavioural changes resides in the fragment 6-17. The influence of DE gamma E appeared to be specific for dopamine systems mediating apomorphine-induced hypomotility, since DE gamma E hardly affected apomorphine-induced stereotypy and amphetamine-induced behavioural changes. These data suggest that DE gamma E acts as a dopamine antagonist selectively, on those dopamine receptor systems which are stimulated by small doses of apomorphine and which may be located presynaptically. In contrast to acute treatment, administration of DE gamma E for 4 days resulted in an enhancement of apomorphine-induced hypomotility. Thus, the receptor systems involved in these effects of apomorphine may become supersensitive upon (sub)chronic treatment with DE gamma E. The significance of the present findings are discussed in relation to the neuroleptic-like and antipsychotic action of gamma-type endorphins.

Animals↗
PubMed1981

APUD cells in teratomas.

The origin of the endocrine cells in the respiratory tract and the gastrointestinal tract is still a matter of debate. In the original concept of the amine precursor uptake and decarboxylation (APUD) system, all APUD cells were considered to be derived from the neural crest. More recently it has been proposed that the APUD cell types of the gastrointestinal and respiratory tracts originate from neuroendocrine-programmed ectoblast. Still other investigators have reported observations that favor a direct endodermal origin of these cell types. Based on the assumption that in teratomas different tissue types which in normal embryogenesis are derived from the neuroectoderm might be expected to occur together, we investigated a series of cystic ovarian teratomas and testicular teratocarcinomas for the presence of brain tissue and of different types of APUD cells. In the ovarian teratomas, intestinal and respiratory APUD cell types were found almost exclusively without coexistence of brain tissue, whereas melanocytes, which are of neuroectodermal origin, occurred mostly together with brain tissue. In the testicular teratocarcinomas, intestinal types of APUD cells occurred without brain tissue. Peptide hormone production was found in appropriate tissues. It can therefore be concluded that in teratomas appropriate intestinal and respiratory APUD cells differentiate in and presumably descend directly from intestinal and respiratory epithelium.

APUD Cells↗