Cognitive impairment and fMRI in major depression

Cognitive impairment in depression may be one of the more practically important aspects of the illness, responsible for much of its morbidity. It also is at the heart of its psychopathology, may contribute to strategies of treatment, and may give us a more easily quantifiable measure of impaired function to correlate with brain activity. Functional magnetic resonance imaging (fMRI) is ideally suited to examine brain function in depression. It has the correct time window to repeatedly sample cognitive task performance; it does not require exposure to radioactive tracers and can therefore be repeated many times; it also can be linked with high resolution structural images acquired in the same imaging session that help identify the regions of activation and support the spatial transformation necessary to compare the scans of different subjects. fMRI has already produced a series of consistent results in depression, identifying increased activity of rostral anterior cingulate and other medial prefrontal structures during effortful tasks and on occasion also increased dorsolateral prefrontal activity, suggesting increased possibly compensatory activity to maintain task performance. Investigating the interplay between limbic (orbitomedial) and 'cognitive' dorsolateral structures clearly has the potential to clarify important illness mechanisms of depressive illness.

Co-twin control designs for testing behavioral economic theories of child nutrition: methodological note

OBJECTIVE

To illustrate the use and potential efficiency of the co-twin control design for testing behavioral economic theories of child nutrition.

DESIGN

Co-twin control design, in which participating twins ate an ad libitum lunch on two laboratory visits. At visit 1, child food choices were not reinforced. On visit 2, twins were randomized to conditions such that one twin was reinforced for each fruit and vegetable serving consumed during lunch ('contingent') while his co-twin was reinforced irrespective of food intake ('non-contingent').

SUBJECTS

Six male twins, 5 years old, from three monozygotic twin pairs.

MEASUREMENTS

Ad libitum intake of total energy (kcals), fat (kcals), and fruits and vegetables (servings) from the protocol test meals on the two visits.

RESULTS

Compared to twins receiving non-contingent reinforcement, twins receiving contingent reinforcement increased fruit and vegetable intake by 2.0 servings, reduced fat intake 106.3 kcals, and reduced total energy intake by 112.7 kcals. The relative efficiency of the co-twin control design compared to a conventional between-groups design of unrelated children was most powerful for detecting 'substitution effects' (i.e., reduced total energy and fat intake) more so than for detecting increased fruit and vegetable intake.

CONCLUSION

Genetically informative studies, including the co-twin control design, can provide conceptually elegant and efficient strategies for testing environmental theories of child nutrition and obesity.

Bayesian decision threshold, detection limit and confidence limits in ionising-radiation measurement

Based on Bayesian statistics and the Bayesian theory of measurement uncertainty, characteristic limits such as the decision threshold, detection limit and limits of a confidence interval can be calculated taking into account all sources of uncertainty. This approach consists of the complete evaluation of a measurement according to the ISO Guide to the Expression of Uncertainty in Measurement (GUM) and the successive determination of the characteristic limits by using the standard uncertainty obtained from the evaluation. This procedure is elaborated here for several particular models of evaluation. It is, however, so general that it allows for a large variety of applications to similar measurements. It is proposed for the revision of those parts of DIN 25482 and ISO 11929 that are still based on conventional statistics and, therefore, do not allow to take completely into account all the components of measurement uncertainty in the calculation of the characteristic limits.

Upper airways abnormalities and tracheal problems in Morquio's disease

Morquio's disease is a metabolic disorder that can cause various respiratory abnormalities. Patients who live into adulthood are likely to develop upper airway problems and respiratory failure. With advances in home ventilation, these patients are increasingly likely to be referred to specialist respiratory units. We describe our experiences with two such patients.

[Endoscopically-assisted adjustment of an oral appliance in patients with obstructive sleep apnoea]

BACKGROUND

The treatment effect of patients suffering from obstructive sleep apnoea/hypopnea (OSAHS) with an oral appliance is considerably varied, and its clinical outcome is unpredictable. The aim of our investigation was to examine the changes in pharyngeal airway size at different degrees of mandibular protrusion in order to assess the therapeutic efficacy in relation to the amount of protrusion.

METHODS

Fifteen patients with the polysomnographic diagnosis of mild to moderate OSAHS were included in this prospective study. Nasal video endoscopy of the pharynx was done with the patients in supine position at four different degrees of mandibular protrusion do assess the changes of airway size. After 3 - 4 weeks a control polysomnography was carried out, with the mandible in optimal protrusion.

RESULTS

The pharyngeal diameter did not increase linearly to the amount of mandibular protrusion. In the polysomnographic examination the respiratory variables were significantly increased. None of the patients in this group was classified as a non-responder to the oral appliance therapy.

CONCLUSIONS

The endoscopically-assisted adjustment of the mandibular protrusion appliance is an additional tool to optimise treatment effectiveness. The increase in pharyngeal diameter is not proportional to the amount of mandibular protrusion.

[Long term compliance with an oral protrusive appliance in patients with obstructive sleep apnoea]

BACKGROUND AND OBJECTIVE

Oral protrusive devices (OPD) are increasingly used in primary snoring and mild-to-moderate obstructive sleep disordered breathing. Due to evidence of reduced compliance with the well established standard treatment of nasal positive airway pressure (CPAP) and reports of patient preference for OPD treatment, particularly in mild cases, OPD may be considered another treatment alternative.

PATIENTS AND METHODS

We contacted 192 patients suffering from obstructive sleep breathing disorder, who were treated between May 1996 and September 2001 with an OPD. The patients" use of the device was evaluated, as were any reasons for ceasing to use the device.

RESULTS

105 patients (54.4%) regularly used the appliance after a mean time of 22.7 12.3 month. 21 patients (10.9%) showed no primary compliance and stopped had using the device before the first somnographic follow-up after a mean time of 3.8 months. In this investigation 76 patients (80,2%) were classified as responders and 19 patients (20.8%) as primary non-responders. 22 responders (11.4%) demonstrated no secondary compliance after a mean of 21.9 8.8 months and the discontinued OPD treatment themselves. In 21 patients (10.9%) the nightly respiratory parameters decreased after a mean of 23.0 11.7 months; hence, those patients required CPAP. The cumulative risk using the device after four years as prescribed was 32.2%. We found a correlation between patient compliance, body-mass index and the amount of teeth in the upper and lower jaws.

CONCLUSION

OPD compliance seems to be lower than frequently expected. Regular follow-up investigations are necessary to ensure adequate treatment. Poor dental status and an excess body-mass index reduce patient compliance.

[Computer-assisted screw osteosynthesis of the posterior pelvic ring. Initial experiences with an image reconstruction based optoelectronic navigation system]

Injuries of the posterior pelvic with combined anterior and posterior instability require the stabilisation of both the anterior and posterior pelvic ring. If the injury only involves the ligamental connections, then a transileosacral osteosynthesis with screws is the minimal invasive and biomechanically suitable method of choice. The difficulty with this approach is the correct placement of the screws. Their position must be monitored intraoperatively in 3 planes (inlet, outlet and lateral viewing). This denotes that conventional methods involve high radiation dosages for the patient and the surgical staff. Having the system readily available and being able to perform updates during the operation, fluoroscopically supported navigation for the treatment of fresh injuries becomes possible. Between October 1999 and December 2000 7 patients with traumatic instability of the posterior pelvic ring were treated by computer assisted percutaneous transileosacral screw osteosynthesis. In each case the osteosynthesis of the ileosacral joint was performed with two cannulated AO 7.3 mm titanium screws. After the operation the screw position was controlled by CT scanning and compared to the data acquired intraoperatively. No patients had infection, and there were no postoperative neurological defects. The postoperative CT scans showed no intraspinal or intraforminal malplacement of the screws. In two cases a slight tangential screwthread penetration through the ventral sacrum was found. Our first experiences with this novel technology are encouraging and clearly demonstrate the advantages of fluoroscopic supported passive navigation systems for the optimal placement of ileosacral screws.

[Intraoral protrusion devices in obstructive sleep apnea. Dental findings and possible treatments]

BACKGROUND

Oral protrusive devices are regarded as an alternative treatment option for snoring and mild to moderate obstructive breathing disorders. In addition to the polysomnographic indication based on the respiratory and somnographic findings, healthy stomatognatic conditions with sufficient dental retention for the device are essential for a successful treatment.

PATIENTS AND METHODS

The sleep laboratory of the University Hospital of Freiburg i. Br. referred 112 patients with obstructive sleep apnea to the Department of Orthodontics for treatment with an oral protrusive device. All patients were examined clinically and with a panoramic radiograph with regard to continuous treatment.

RESULTS

To maximize treatment success and minimize dental side effects, close collaboration with dental colleagues is necessary in treatment with an oral protrusive device.

CONCLUSIONS

Acute periodontitis, periodontal lesions, insufficient dental anchorage, and temporomandibular symptoms can result in unwanted dental side effects and therefore limit the indication of this therapeutic approach.

Phase 1 study of polyethylene glycol formulation of interferon alpha-2B (Schering 54031) in Philadelphia chromosome-positive chronic myelogenous leukemia

Interferon alpha (IFN-alpha) therapy improves prognosis in Philadelphia chromosome (Ph)-positive chronic myelogenous leukemia (CML). Polyethylene glycol (PEG) attached to IFN-alpha prolongs its half-life and may offer better therapy. The aims of this phase 1 study were to define the maximal tolerated dose (MTD), dose-limiting toxicities (DLTs), and response with PEG IFN-alpha-2b. Twenty-seven adults with Ph(+) CML in chronic or accelerated phases, in whom IFN-alpha treatment had failed, were studied. Patients had hematologic (9 patients) or cytogenetic resistance (12 patients) or intolerance to IFN-alpha (6 patients). PEG IFN-alpha-2b was given as a weekly subcutaneous injection starting at 0.75 microg/kg weekly and escalating to 1.5, 3, 4.5, 6, 7.5, and 9.0 microg/kg. The MTD was defined at 7.5 to 9 microg/kg; DLT included severe fatigue, neurotoxicity, liver function abnormalities, and myelosuppression. Longer administration of PEG IFN-alpha-2b resulted in chronic side effects not observed earlier, which defined the MTD and DLT. The proposed phase 2 dose of PEG IFN-alpha-2b was 6 microg/kg weekly. Among 19 patients with active disease, 7 (37%) achieved complete hematologic response (CHR); 2 (11%) had a cytogenetic response (complete). Among 8 patients treated in CHR, 7 (87%) improved cytogenetic response to complete (4 patients) or partial (3 patients). All 6 patients intolerant to IFN-alpha tolerated PEG IFN-alpha-2b; 4 improved their cytogenetic response. The results show that PEG IFN-alpha-2b is easier to deliver (once weekly), better tolerated, and perhaps more effective than IFN-alpha.

Coordinate changes in drug resistance and drug-induced conformational transitions in altered-function mutants of the multidrug transporter P-glycoprotein

The MDR1 P-glycoprotein (Pgp), responsible for a clinically important form of multidrug resistance in cancer, is an ATPase efflux pump for multiple lipophilic drugs. The G185V mutation near transmembrane domain 3 of human Pgp increases its relative ability to transport several drugs, including etoposide, but decreases the transport of other substrates. MDR1 cDNA with the G185V substitution was used in a function-based selection to identify mutations that would further increase Pgp-mediated resistance to etoposide. This selection yielded the I186N substitution, adjacent to G185V. Pgps with G185V, I186N, or both mutations were compared to the wild-type Pgp for their ability to confer resistance to different drugs in NIH 3T3 cells. In contrast to the differential effects of G185V, I186N mutation increased resistance to all the tested drugs and augmented the effect of G185V on etoposide resistance. The effects of the mutations on conformational transitions of Pgp induced by different drugs were investigated using a conformation-sensitive antibody UIC2. Ligand-binding analysis of the drug-induced increase in UIC2 reactivity was used to determine the K(m) value that reflects the apparent affinity of drugs for Pgp, and the Hill number reflecting the apparent number of drug-binding sites. Both mutations altered the magnitude of drug-induced increases in UIC2 immunoreactivity, the K(m) values, and the Hill numbers for individual drugs. Mutation-induced changes in the magnitude of UIC2 reactivity shift did not correlate with the effects of the mutations on resistance to the corresponding drugs. In contrast, an increase or a decrease in drug resistance relative to that of the wild type was accompanied by a corresponding increase or decrease in the K(m) or in both the K(m) and the Hill number. These results suggest that mutations that alter the ability of Pgp to transport individual drugs change the apparent affinity and the apparent number of drug-binding sites in Pgp.

Speed of sound measurements in mandibular and phalangeal bone during growth

The micromechanical and elastic properties of bone, its structural maturity and, indirectly, mineral density are important factors for the planning and assessment of orthodontic and/or jaw orthopaedic treatment. This clinical study was undertaken to evaluate age-related changes in the anterior mandibular body. The speed of sound (SOS) has demonstrated age dependency in various peripheral bones and has been proposed as an alternative method for investigating bone parameters without the use of radiation. The ultrasound transmission velocity was measured in 184 healthy subjects (93 females, 91 males; mean age 17.6 +/- 13.7 years). According to the statistical analysis, the data did not reveal any gender-related differences, but were significantly age-dependent. Different kinetics were established between the maturity of the phalanx and the anterior mandible. Further clinical investigations of age-dependent structural changes in bone maturation parameters may provide information that should be taken into account for early functional jaw orthopaedic treatment.

Dental age in southwest Germany. A radiographic study

A cross-sectional study was undertaken in order to assess the dental age of healthy Southwest German boys and girls between the ages of 2 and 20 years by evaluating 1,003 panoramic radiographs. Dental age was assessed according to the method of Demirjian et al. All permanent teeth of the lower left jaw except the third molar were rated, the development of each tooth was divided into 8 defined stages. Statistical evaluation revealed a correlation between the parameters chronological age and score sum of r = 0.85 for girls and r = 0.89 for boys. The values of the score sum in relation to chronological age were distributed as in a logistic function. Two gender-specific equations for calculating dental age were devised and a marked sexual dimorphism was found. With the beginning of root formation, the girls showed accelerated development. The fact that dental age distribution in Southwest Germany is not significantly correlated to that of a French-Canadian collective underlines Demirjian's demand for regional standards of dental development to be calculated using his score system.

Multiple advantages of alpha-fetoprotein as a marker for in vivo gene transfer

The development of improved gene transfer vectors has been hampered by the lack of a nonimmunogenic reporter gene that can be serially quantified in the serum or from other sites. In response to the need to develop a new reporter protein, we have evaluated alpha-fetoprotein (AFP) as a potential candidate. A first-generation E1/E3-deleted adenoviral vector expressing human AFP (hAFP) was generated as a preliminary tool to evaluate AFP as a reporter. Using both mouse and baboon models, hAFP expression was evaluated in serum after intravenous delivery and in serum and bronchioalveolar lavage (BAL) fluid after delivery to the lung. In immunocompetent animals, intravenous delivery of the hAFP adenoviral vector resulted in hAFP expression in the serum early after injection, which declined rapidly over time. Disappearance of hAFP from the serum was complete by 3-4 weeks after administration and was accompanied by robust antibody responses to hAFP and loss of infected cells. After lung delivery, hAFP could be detected in both serum and BAL. This allowed the analysis of the kinetics of gene expression in the lung without sacrificing the animals. In both liver and lung, immunohistochemical analysis correlated well with hAFP levels as detected in serum or BAL, indicating that serum levels were a reliable marker of tissue expression. Preliminary results with a mouse AFP expressed in a helper-dependent adenoviral vector indicate that use of a species-specific version of AFP will eliminate the complication of antibody development. These initial evaluations suggest that AFP is useful as a reporter gene to evaluate gene expression of therapeutic cassettes in multiple tissues, and it should be considered for use in human subjects.

Using ultrasound transmission velocity to analyse the mechanical properties of teeth after in vitro, in situ, and in vivo irradiation

Ultrasound transmission velocity (UTV) in isotropic material as a measure for the modulus of elasticity was correlated to mechanical properties. Changes in micromechanical properties of radiated teeth and influence of the oral cavity were to be evaluated nondestructively. UTV was measured in extracted teeth after 36 Gy and 62 Gy of in situ (enorally, with no contact to the oral cavity) and in vitro irradiation. Relative to controls, teeth subjected to 62 Gy in vivo showed higher UTV values for dentine and enamel. Sound teeth irradiated with 60 Gy in situ also showed higher UTV values for enamel, whereas dentine values were not significantly different from those of control. The mechanical properties of teeth irradiated in vitro were affected only after high experimental doses of up to 500 Gy. The difference between in vivo and in vitro mechanical properties may be due to radioxerostomia-induced damages as well as the status of dentine vitality. This supports the concept of direct radiation-induced damage in synergy with radioxerostomia-induced caries.