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Biomedical subjects

C Jansen

Publications and source records attributed to C Jansen.

At least 55 records · Page 3Linked to original sources
PubMed1996

Localization of a gene for Möbius syndrome to chromosome 3q by linkage analysis in a Dutch family.

Möbius syndrome (MIM no. 157900) consists of a congenital paresis or paralysis of the VIIth cranial nerve, frequently accompanied by paralysis of other cranial nerves, orofacial and limb malformations, defects of the musculoskeletal system and mental retardation. Although most patients are sporadic cases, familial recurrence is not rare. Different pedigrees suggest different modes of inheritance. We performed linkage analysis in a large family with autosomal dominantly inherited Möbius syndrome, consisting essentially of asymmetric bilateral facial pareses. After exclusion of the candidate region for Möbius syndrome on 13q12.2-q13, we localized the gene to chromosome 3q21-22, indicating genetic heterogeneity of Möbius syndrome. This heterogeneity is further proven by the exclusion of both loci in a second family with Möbius syndrome.

Chromosome Mapping↗
PubMed1996

Automatic embolus detection compared with human experts. A Doppler ultrasound study.

BACKGROUND AND PURPOSE: Transcranial Doppler ultrasound (TCD) reliably detects the occurrence of microembolic signals (MES). Unfortunately, TCD monitoring is a time-consuming and mentally strenuous procedure. The purpose of this study was to assess whether automatic embolus detection software devices acting as a "stand-alone system" are able to identify MES in patients with solid cerebral microemboli. METHODS: Ten records of TCD monitoring of the middle cerebral artery in patients with symptomatic high-grade carotid artery stenosis were analyzed for the moments at which MES occurred by four observers and three automatic detection software devices (RB11 on TC2000, Pioneer Version 2.10, and Embotec). The results of the three software systems were assessed on the basic assumption that MES were present if at least three of the four observers agreed. RESULTS: The average number of 1-second periods in which MES were detected by the four observers per tape ranged from 5 to 39. The overall kappa values (and SEs) for chance-corrected interobserver agreement between the four observers ranged from .94 (.02) to .99 (.01). The agreement between the software devices and the observers was lower, with kappa values (and SEs) ranging from .18 (.17) to .93 (.07). The RB11 and Embotec systems achieved a kappa value higher than 0.4 in all tapes. The Pioneer system failed to reach a kappa value of 0.4 in three tapes. The RB11 showed a sensitivity of 70% for detecting MES, the Embotec 62%, and the Pioneer 44%. CONCLUSIONS: In patients with symptomatic high-grade carotid artery stenosis, a high degree of agreement in the detection of moments of MES can be achieved between observers. The three automatic detection software devices reached less agreement. Supervision of TCD monitoring and assessment of MES by an experienced observer is still necessary.

Carotid Stenosis↗
PubMed1996

[Liability of the expert witness].

Regarding the liability of the expert witness, is has to be differentiated between the responsibility according to the civil law and the criminal law. Responsibility in the criminal law means the punishableness for the guilty and illegal fulfillment of a criminal offense in the legal sense, while responsibility in the civil law means compensation towards another citizen. Criminal prosecution occurs ex officio. Prerequisite for prosecution in the civil law is an action of the victim.

Ethics, Medical↗
PubMed1995

The significance of microemboli detection by means of transcranial Doppler ultrasonography monitoring in carotid endarterectomy.

PURPOSE: Carotid endarterectomy (CEA) performed with continuous transcranial Doppler monitoring provides a unique opportunity to determine the number of cerebral microemboli and to relate their occurrence to the surgical technique. The purpose of this study was to assess in CEA the impact of cerebral microembolism on clinical outcome and brain architecture. We also evaluated the influence of the audible transcranial Doppler signal on the surgeon and his or her technique. METHODS: In a prospective series of 301 patients, CEA was monitored with electroencephalography and transcranial Doppler ultrasonography of the ipsilateral middle cerebral artery. Preoperative and intraoperative risk factors were entered in a logistic regression analysis program to assess their correlation with cerebral outcome. To evaluate the impact of cerebral microembolism on brain architecture, we compared preoperative and postoperative computed tomography scans or magnetic resonance images of the brain in two subgroups of 58 and 40 patients, respectively. RESULTS: Seven (2.3%) patients had intraoperative transient ischemic symptoms, three (1%) had intraoperative strokes, 1 (0.3%) had transient ischemic symptoms after operation, and 10 (3.3%) had postoperative strokes. Four (1.3%) patients died. Microemboli (> 10) noticed during dissection were related to both intraoperative (p < 0.002) and postoperative (p < 0.02) cerebral complications. Microemboli that occurred during shunting were also related to intraoperative complications (p < 0.007). Microembolism never resulted in new morphologic changes on postoperative computed tomography scans. On the contrary, the phenomenon of more than 10 microemboli during dissection was significantly (p < 0.005) related to new hyperintense lesions on postoperative T2-weighted magnetic resonance images. CONCLUSIONS: During CEA the presence of microembolism (> 10 microemboli) during dissection shows a statistically significant relationship with perioperative cerebral complications and with new ischemic lesions on magnetic resonance images of the brain. Moreover, microembolism during shunting is also related to intraoperative complications. Surgeons can be guided by the audio Doppler and emboli signals by changing their technique. This change may result in a decrease of microembolism and consequently in a decline of the intraoperative stroke rate.

Adult↗
PubMed1995

[Liability in ambulatory surgery from the legal viewpoint].

According to the act to the structural reform of the public health service from Jan. 1, 1993, every hospital may do surgery on outpatients without a specific license. The legal basis for the outpatient surgery ares sec. 39, 115b SGB V. Additionally, there are two contracts containing three pages between the health insurances, the society of German hospitals and the German association of panel physicians. The legal requirements for ambulant surgery regarding the liability are written down in contracts where surgery has to meet a specialist's quality. There are certain risks during the care after surgery. The patient has to be informed about kind, extend and technique of the surgery.

Ambulatory Surgical Procedures↗
PubMed1994

Prediction of intracerebral haemorrhage after carotid endarterectomy by clinical criteria and intraoperative transcranial Doppler monitoring.

Intracerebral haemorrhage is a serious complication after carotid endarterectomy. We tried to identify predictors of this event. Two-hundred-and-thirty-three operations were selected from a total of 280 because of reliable intraoperative transcranial Doppler data with regards to the increase of peak blood flow velocities and pulsatility indices in the ipsilateral middle cerebral artery after release of the internal carotid artery cross-clamp. We also recorded the occurrence of unilateral throbbing headache or hypertension after the operation. Five patients developed an intracerebral haemorrhage after the operation. Seventeen patients developed headache or hypertension after surgery, four of whom developed an intracerebral haemorrhage (p < 0.001; Fisher's exact test). The positive predictive value of headache, hypertension, or both, for intracerebral haemorrhage was 24% (diagnostic gain 22%). The negative predictive value, sensitivity and specificity were 99, 80 and 94%, respectively. The increase of peak blood flow velocities and pulsatility indices in patients who developed intracerebral haemorrhage was significantly higher than in patients who did not (p < 10(-5); one-way ANOVA). With appropriate cut-off levels for the increase of peak blood flow velocities (> or = 175% increase) or pulsatility indices (> or = 100% increase) after release of the cross-clamps, the positive predictive value of intraoperative transcranial Doppler for intracerebral haemorrhage was 100% (diagnostic gain 98%). The negative predictive value, sensitivity and specificity were 99, 80 and 100%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Prediction of intracerebral haemorrhage after carotid endarterectomy by clinical criteria and intraoperative transcranial Doppler monitoring: results of 233 operations.

OBJECTIVE: Identification of predictors of intracerebral haemorrhage after carotid endarterectomy. DESIGN: Retrospective comparison of patients who developed intracerebral haemorrhage and patients who did not, with special attention to intraoperative transcranial Doppler monitoring of the ipsilateral middle cerebral artery and postoperative signs and symptoms of hypoperfusion. SUBJECTS AND MATERIALS: Two-hundred and thirty-three patients were studied with regard to the increase of peak blood flow velocities and pulsatility indices after endarterectomy and to the occurrence of unilateral throbbing headache or hypertension. RESULTS: Intracerebral haemorrhage occurred in five cases. Seventeen patients complained of headache or showed hypertension, four of whom developed an intracerebral haemorrhage (p < 0.001; Fisher's exact test). The positive predictive value of headache, hypertension, or both, was 24% (diagnostic gain 22%). The negative predictive value, sensitivity and specificity were 99, 80 and 94%, respectively. The increase of peak blood flow velocities and pulsatility indices in patients who developed intracerebral haemorrhage was significantly higher than in patients who did not (p < 10(-5); one-way ANOVA). When cut-off levels for the increase of peak blood flow velocities and pulsatility indices were set to 175 and 100%, respectively, the positive predictive value of intraoperative transcranial Doppler was 100% (diagnostic gain 98%). The negative predictive value, the sensitivity and specificity were 99, 80 and 100%, respectively. CONCLUSION: An increase of peak blood flow velocity > or = 100% or pulsatility index > or = 100% after declamping predicts intracerebral haemorrhage more accurately than the occurrence of headache or hypertension. Transcranial Doppler monitoring can be used to identify patients at risk for intracerebral haemorrhage, in whom control of blood pressure and modest degrees of anticoagulation may be appropriate.

Cerebral Hemorrhage↗
PubMed1994

Impact of microembolism and hemodynamic changes in the brain during carotid endarterectomy.

BACKGROUND AND PURPOSE: Monitoring of carotid endarterectomy with electroencephalography and transcranial Doppler ultrasonography provides instantaneous information about hemodynamic changes and embolic signals. However, a relation between these findings and intraoperative infarcts has not yet been demonstrated. METHODS: In this study we compared preoperative and post-operative computed tomographic scans (58 patients) or magnetic resonance imaging (40 patients) of the brain, assessed by two independent observers, to detect intraoperative infarcts, and we related any such new lesions to the findings of intraoperative monitoring. RESULTS: In the computed tomography series one intraoperative infarct occurred, with corresponding clinical deficits. In the magnetic resonance group four patients developed new lesions that occurred intraoperatively, all of which were clinically silent. There was a significant relation between the number of embolic signals during the surgical dissection of the carotid artery and the occurrence of intraoperative infarcts (P < .005). Three of the four infarcts were of the lacunar type; the fourth patient had a border-zone infarct, associated not only with many embolic signals but also with low flow during cross-clamping. There were no demonstrable ultrasound side effects on brain tissue. CONCLUSIONS: Embolic signals detected by transcranial Doppler monitoring in the dissection phase of carotid endarterectomy show a significant relation to new ischemic lesions and therefore are potentially harmful. The phenomenon should alert the vascular surgeon.

Adult↗
PubMed1993

Continuous transcranial Doppler ultrasonography and electroencephalography during carotid endarterectomy: a multimodal monitoring system to detect intraoperative ischemia.

Transcranial Doppler ultrasonography (TCD) and EEG monitoring during carotid endarterectomy provide continuous information on the electrical activity of the cerebral cortex, blood flow velocities in the ipsilateral middle cerebral artery, and the occurrence of microemboli. One hundred thirty carotid endarterectomies performed with TCD and EEG monitoring were studied prospectively. During cross-clamping of the carotid artery a high correlation was found between EEG asymmetry and reduction of blood flow velocity in the middle cerebral artery (p < 10(-6), Student's t test). Microemboli were detected in 80 patients during the operation. Although not statistically significant, this occurrence of microemboli was associated with signs and symptoms of intraoperative ischemia (p = 0.08, Fisher's exact test). In comparison with earlier studies, a tendency toward intraoperative stroke reduction was noted. Only one nondisabling intraoperative stroke occurred (0.8%). In addition to the EEG, TCD monitoring of hemodynamic changes and microemboli in the middle cerebral artery provides important information to the surgeon instantaneously. TCD monitoring of blood flow velocities and embolism during carotid endarterectomy may help to reduce the number and gravity of intraoperative stroke.

Adult↗
PubMed1993

Carotid endarterectomy with transcranial Doppler and electroencephalographic monitoring. A prospective study in 130 operations.

BACKGROUND AND PURPOSE: We report the results of combined recording of hemodynamic and thromboembolic phenomena during carotid endarterectomy by means of computerized electroencephalography as well as transcranial Doppler ultrasonography. The study focuses on the additional value of transcranial Doppler to detect ischemia during surgery. METHODS: Combined monitoring was performed in 130 consecutive operations, using standard anesthesiological, surgical, and neurophysiological procedures. RESULTS: A reduction of > or = 70% of blood flow velocities in the middle cerebral artery during cross-clamping was measured in 16 patients. In seven of these cases there were no severe electroencephalographic changes and a shunt was not used, but one of the patients developed a subcortical infarct with slight disability. In 55 patients, 75 episodes of embolization were detected by transcranial Doppler. In one of these, with massive embolization after release of the clamp, an intraoperative stroke occurred without changes on cranial computerized tomography or neurological disability on follow-up. In the other 54 patients, intraoperative embolization did not cause clinical or neuroradiological symptoms. Electroencephalographic changes occurred in only two of the 75 episodes. In addition to the two nondisabling strokes during surgery (1.5%), six strokes occurred within 5 days of operation, including one hemorrhage. There was no significant relation between contralateral carotid occlusion and stroke (p = 0.6). CONCLUSIONS: During carotid endarterectomy, transcranial Doppler immediately provides information about thromboembolism and hemodynamic changes that are not detected by electroencephalography alone. Acoustic feedback from the transcranial Doppler monitoring unit has a direct influence on the surgical technique. Transcranial Doppler ultrasound may be a useful tool in the study and prevention of intraoperative stroke.

Adult↗
PubMed1993

Two novel pathogenic mitochondrial DNA mutations affecting organelle number and protein synthesis. Is the tRNA(Leu(UUR)) gene an etiologic hot spot?

We identified two patients with pathogenic single nucleotide changes in two different mitochondrial tRNA genes: the first mutation in the tRNA(Asn) gene, and the ninth known mutation in the tRNA(Leu(UUR)) gene. The mutation in tRNA(Asn) was associated with isolated ophthalmoplegia, whereas the mutation in tRNA(Leu(UUR)) caused a neurological syndrome resembling MERRF (myoclonus epilepsy and ragged-red fibers) plus optic neuropathy, retinopathy, and diabetes. Both mutations were heteroplasmic, with higher percentages of mutant mtDNA in affected tissues, and undetectable levels in maternal relatives. Analysis of single muscle fibers indicated that morphological and biochemical alterations appeared only when the proportions of mutant mtDNA exceeded 90% of the total cellular mtDNA pool. The high incidence of mutations in the tRNA(Leu(UUR)) gene suggests that this region is an "etiologic hot spot" in mitochondrial disease.

Adult↗
PubMed1993

Family problems during cancer chemotherapy.

Although reports suggest that a cancer diagnosis affects all members of a family, limited descriptions are available of the types of problems families experience when a family member has cancer. Adult patients with cancer (n = 100) and their family members (n = 126) were interviewed in their homes at 1 1/2 weeks, 7 1/2 weeks, and 6 months following the initiation of chemotherapy. The Problem Centered Family Coping Interview, a semistructured tool with established content validity, was used to identify family problems that occurred in the previous month. Content analysis was performed on interviews using empirically based categories. Families reported from one to eight problems occurring in the previous month (mean = 3.4). Cancer-related health concerns accounted for 48%-52% of the problems identified at all three interviews. This study's findings enhance knowledge about the family's cancer experience.

Adaptation, Psychological↗