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Biomedical subjects

C Neu

Publications and source records attributed to C Neu.

At least 19 recordsLinked to original sources
PubMed2001

The development of metaphyseal cortex--implications for distal radius fractures during growth.

Fractures of the distal radial metaphysis are very common in otherwise healthy children. The reasons for this high fracture incidence are not entirely clear. To address this problem, we undertook a detailed analysis of distal radius development using peripheral quantitative computed tomography (pQCT) at a site 4% proximal to the radial articular surface. The study population comprised 337 healthy children and adolescents (aged 6-18 years; 171 girls) and 107 adults (aged 29-40 years; 88 women). Total volumetric bone mineral density (vBMD) remained stable at about 70% of the adult value between the ages of 6-7 years and 14-15 years in both genders. Cortical thickness increased little between 6-7 years and 12-13 years in girls and 14-15 years in boys. Strength-Strain Index (SSI; a parameter combining geometry and density) was still at only 20% of the adult value in girls aged 10-11 years and at 21% of the adult level in boys aged 12-13 years. At these ages, factors that contribute to the mechanical challenge to the distal radius in case of a fall (forearm length and body weight) had already reached 49% and 36% of the adult value in girls and boys, respectively. The shaping of the distal radius cortex (metaphyseal inwaisting) was assessed by analyzing the decrease in cross-sectional bone size between adjacent bone slices in a separate population of 44 children (aged 8-19 years; 26 girls). The rates of periosteal resorption and endocortical apposition were estimated to average 8 microm/day and 10 microm/day, respectively, during the growth period. In conclusion, during growth the increase in distal radius strength lags behind the increase in mechanical challenges caused by a fall, because metaphyseal cortical thickness does not increase sufficiently. The endocortical apposition rate is already very high at that site and apparently cannot be further increased to levels that would be necessary to keep bone strength adapted to the mechanical requirements.

Adolescent↗
PubMed2000

In vivo scaphoid, lunate, and capitate kinematics in flexion and in extension.

Carpal kinematics have been previously limited to in vitro models with cadaveric specimens. Using a newly developed markerless bone registration algorithm, we noninvasively studied the in vivo kinematics of the capitate, scaphoid, and lunate during wrist extension and flexion in both wrists of 5 men and 5 women. Computed tomography volume images were acquired in neutral and in 2 positions in both extension and flexion. The 3-dimensional kinematics of the capitate, scaphoid, and lunate relative to the radius were the determined. Scaphoid and lunate rotations differed for flexion and extension but were found to vary linearly with capitate rotation. In flexion the scaphoid contributed 73% of capitate motion and the lunate contributed 46%. In extension the scaphoid contributed 99% of capitate motion and the lunate contributed 68%. Contributions of the scaphoid and lunate to wrist extension were 15% greater than values reported in previous in vitro studies, while scaphoid and lunate contributions to wrist flexion were more similar to previous studies. The findings support a relative "engagement" of the scaphoid, capitate, and lunate during wrist extension. The only difference between male and female kinematics was a more distal location of the rotation axes; we believe this was due to a difference in carpal bone size, not gender. This study reports the 3-dimensional in vivo measurement of carpal motion using a noninvasive technology. This technique may prove useful in the study of more complex motions of the hand and wrist and of the abnormal kinematics that occur following ligamentous injury.

Adult↗
PubMed1979

Differential symptom reduction by drugs and psychotherapy in acute depression.

A randomized, controlled trial compared the combination of amitriptyline hydrochloride and short-term interpersonal psychotherapy, either treatment alone, and a nonscheduled treatment control group in ambulatory acute, nonbipolar, nonpsychotic depressives. Results show the efficacy of both psychotherapy and amitriptyline in overall symptom reduction. Amitriptyline and psychotherapy were about equal, and the effects of both treatments in combination were additive. The additive effect of combined treatment was largely due to the differential effects of the two treatments. Amitriptyline had its effect mainly on the vegetative symptoms of depression such as sleep and appetite disturbance, these occurred early in treatment, often within the first week. Psychotherapy had its effect mainly on mood, suicidal ideation, work, and interests; these effects occurred slightly later, at four to eight weeks.

Adolescent↗
PubMed1979

The efficacy of drugs and psychotherapy in the treatment of acute depressive episodes.

The efficacy of tricyclic antidepressants and various psychotherapies, in comparison with one another or in combination, has not been fully established in randomized clinical trials. The authors present a randomized controlled trial comparing the combination of amitriptyline and short-term interpersonal psychotherapy, either treatment alone, and nonscheduled supportive psychotherapy in ambulatory patients with acute depression. They found that pharmacotherapy and psychotherapy alone were equally efficacious and better than nonscheduled treatment. The combination treatment of psychotherapy and pharmacotherapy was more effective than either treatment alone and delayed the onset of symptomatic failure.

Adolescent↗
PubMed1979

Renal damage associated with long term use of lithium carbonate.

The authors report 2 cases of renal damage associated with lithium carbonate treatment. The relevant literature is reviewed and supports the claim that the lithium ion may be nephrotoxic. The article concludes with practical recommendations for clinical practice until futher evidence regarding this association is available.

Adult↗
PubMed1978

Spectrophotofluorometric analysis of 3',4',7-tris[O-(beta-hydroxyethyl)]rutoside in urine.

A sensitive procedure was developed for 3',4',7-tris[O(beta-hydroxyethyl)]rutoside (I) in urine. The method is based on the fluoresence behavior of the I-aluminum complex in absolute methanol. This complex has activation and emission wavelengths of 420 and 480 nm, respectively. Optimum conditions for the reaction were investigated. The fluorescence was linear (r = 0.998) in the range of 0.1-4.0 microgram of I/ml. At concentrations below 0.1 microgram/ml, a shift in the emission wavelength was observed. Replicate studies (n = 9) of spiked urine samples, each containing 0.4 microgram of I/ml, showed good precision with a relative standard deviation of 0.009. Overall percent recovery (+/- SEM) from five urine samples was 99.5 +/- 1.34%. Following a single 500-mg po dose of I to individuals, only traces of I were found in the urine. However, beta-glucuronidase treatment of urine resulted in a total cumulative urine excretion of 26.53 mg of I after 78.6 hr.

Glucuronates↗
PubMed1975

Saliva lithium levels: clinical applications.

The authors note that despite a few reports in the literature indicating that saliva lithium levels could adequately replace serum determinations in monitoring patients being treated with lithium salts, this procedure has not received much clinical application. A study of 20 patients investigated correlations between serum and mixed saliva and parotid fluid lithium levels and documented the reliability of this procedure. The authors suggest that an individual patient's ratio of serum to saliva concentrations should be calculated and used as a constant in the determinations. Patients can collect saliva samples and send them to the laboratory prior to their visits, decreasing the facility's sample collection costs and the patients' inconvenience and discomfort.

Bipolar Disorder↗