Bone marrow imaging: magnetic resonance studies related to age and sex

Measurements of T1 and T2 relaxation values and spin density of the lumbar vertebral bone marrow were performed in 212 patients, and the results were correlated with the patients' age and sex. T1 and T2 relaxation times for bone marrow in the lumbar vertebral bodies showed a progressive decrease with age for both sexes (except for the T2 relaxation values in female patients). The replacement of hematopoietic marrow by fatty marrow could explain the decrease in T1 and T2. The T1 and T2 values were in the same range for the first two age groups (age 1-10 years and age 21-40 years) and became slightly greater for the older female patients (age 51 years and older) than for the older males. This could be due to the loss of bone and mineral content, which is more rapid and significant for women. These normal T1 and T2 values may provide a baseline for future evaluation of diseases involving the lumbar spine.     

Apomorphine delays simple reaction time in Parkinsonian patients

BACKGROUND: Parkinsonian patients have difficulty in the preparation and execution of movements, which translate into delayed performance of simple reaction time (SRT) paradigms. OBJECTIVE: To examine short-term effects of an acute subcutaneous injection of the dopamine agonist apomorphine on the results of a SRT task. METHODS: We studied a SRT paradigm in 26 non-fluctuating idiopathic Parkinsonian patients, before and 30, 60, 90 min after administration of apomorphine. RESULTS: The reaction time (RT) was significantly delayed after apomorphine injection. We found no significant change in movement time (MT). CONCLUSION: Delay of RT and the lack of response of MT to apomorphine administration may result from the sedative effects of apomorphine, overstimulation of postsynaptic dopaminergic receptors with subsequent inhibition of prefrontal cholinergic neurotransmission, and at least partial binding of apomorphine to presynaptic dopaminergic autoreceptors, which cause inhibition of locomotor activity. We suggest that future studies testing the capacity for reaction in Parkinsonian patients should consider the exact timing of the delivery of dopamine substituting drugs prior to the test.     

Echogenicity of the substantia nigra: association with increased iron content and marker for susceptibility to nigrostriatal injury

BACKGROUND: Patients with Parkinson disease characteristically exhibit an increased echogenicity of the substantia nigra (SN) on transcranial sonography, a new neuroimaging technique. The same echo feature of the SN can be identified in 9% of healthy adults. OBJECTIVE: To evaluate the relevance of the echogenic SN in healthy adults. DESIGN: In the first part of the study, 10 healthy subjects younger than 40 years with a distinct SN hyperechogenicity underwent extensive neurological, motor, neuropsychological, and fluorine 18-dopa positron emission tomographic ([18F]-dopa PET) examinations. Results were compared with those of 10 subjects with a low echogenic SN. In the second part of the study, the postmortem brains of 20 patients without extrapyramidal disorders during their lifetime were sonographically examined with a particular focus on SN echogenicity. Subsequently, one half of the brain was prepared for heavy metal analysis, the other for a histological examination. RESULTS: Healthy subjects with SN hyperechogenicity exhibited a significant reduction of the [18F]-dopa uptake, especially in the putamen (Wilcoxon matched pair test: left side, P =.006; right side, P =.009), whereas their neuropsychological and motor performance were normal. Postmortem studies showed that the echogenicity of the SN correlated with its iron content. CONCLUSIONS: Increased echogenicity of the SN, characteristically seen in Parkinson disease, is related to a functional impairment of the nigrostriatal system (even in young healthy adults) that can be revealed by [18F]-dopa PET studies. Substantia nigra hyperechogenicity is related to a higher tissue iron level, which is known to enhance the cells' generation of reactive oxygen specimens. Therefore, we hypothesize that transcranial sonography may identify a susceptibility marker for the development of nigral injury that can be detected early in life, prior to the onset of Parkinson disease.     

Testicular function after radioiodine therapy for thyroid carcinoma

Radiotherapy can cause infertility in both men and women. However, few data are available concerning the effects of radioiodine therapy for thyroid carcinoma on testicular function. We investigated 25 men (age 23-73 years) with differentiated thyroid carcinoma in a longitudinal prospective trial. Follicle-stimulating hormone (FSH), inhibin B, luteinising hormone (LH) and testosterone were measured before (n = 25) and 3 months (n = 11), 6 months (n = 18), 12 months (n = 22), and 18 months (n = 18) after radioiodine therapy [radioiodine dose (mean +/- SEM): 9.8+/-0.89 GBq]. Before therapy, FSH was 5.4+/-0.77 IU/l; it increased significantly (P<0.001) to 21.3+/-2.4 IU/l after 6 months and fell to 7.4+/-1.3 IU/l after 18 months (normal range: 1.8-9.2 IU/l). Inhibin B was significantly decreased (P<0.001) from 178+/-25.3 pg/ml before therapy to 22.2+/-5.5 pg/ml after 3 and 29.4+/-5.7 pg/ml after 6 months and rose to 154+/-23.3 pg/ml after 18 months (normal range 75-350 pg/ml). LH and testosterone were within the normal range during the whole study (1.6-9.2 IU/l and 10.4-34.7 nmol/l, respectively). LH was significantly increased (P<0.001) from 2.8+/-0.33 IU/l before therapy to 5.9+/-0.69 IU/l 6 months after therapy and then fell slowly to 4.0+/-0.45 IU/l after 18 months. Total testosterone was significantly increased (P<0.01) from 12.8+/-0.99 nmol/l at baseline to 19.8+/-1.7 nmol/l after 12 months and 19.6+/-1.7 nmol/l after 18 months. The testosterone/LH ratio (normal range: 3.3-17.9 nmol/IU) fell from 5.8+/-0.66 nmol/IU to 3.0+/-0.36 nmol/IU after 3 months (P<0.01); it remained close to the latter value after 6 months (3.4+/-0.49 nmol/IU) and then rose to 5.5+/-0.6 nmol/IU after 18 months. In conclusion, 3 and 6 months after radioiodine therapy all patients showed elevated FSH and decreased inhibin B levels, reflecting severely impaired spermatogenesis. At the same time a compensated insufficiency of the Leydig cell function was observed. Eighteen months after the last radioiodine therapy, mean values of gonadal function had completely recovered.     

Practice MRI: Reducing the need for sedation and general anaesthesia in children undergoing MRI

The aim of this study was to evaluate the effectiveness of a practice magnetic resonance unit, in preparing children to undergo magnetic resonance procedures without general anaesthesia (GA) or sedation. The records of children who attended the practice MRI between February 2002 and April 2004 were retrospectively reviewed. Each record was assessed as to whether the child had passed or failed the practice MRI intervention. Those children who were considered to have passed and were proceeded to a clinical non‐GA MRI had the report of the clinical scan reviewed. If the scan had been reported as non‐diagnostic because of movement artefact it was classified as a failed scan, otherwise it was considered a pass. One hundred and thirty‐four children undertook a practice MRI (age range 4.1–16.1 years, median age 7.7 years, 47% boys) and 120/134 (90%) passed the practice session. In all, 117/120 (98%) subsequently had a clinical non‐GA MRI and 110/117 (94%) passed (median age 7.8 years, 47% boys). Preparation is a safe and effective method to reduce the need for sedation and GA in children undergoing a clinical MRI scan. It provides a positive medical experience for children, parents and staff, and results in cost savings for the hospital.     

Double blind, placebo controlled study of nedocromil sodium in asthma

After a two week baseline, 209 asthmatic children (mean age 10 years, range 6-17) were randomly allocated to receive 4 mg nedocromil sodium (n = 110) or placebo (n = 99) four times daily for 12 weeks in addition to their current treatment. The children completed daily diary cards and visited the clinic at four week intervals. Statistically significant differences in favour of nedocromil sodium were seen for clinician assessment of asthma severity and diary card symptom scores, pulmonary function and inhaled beta 2 bronchodilator use. Total symptom score decreased by 50% from baseline in the nedocromil sodium group and by 9% in the placebo group during the final four weeks. Nedocromil sodium was considered very or moderately effective by 78% of children/parents (placebo 59%) and 73% of clinicians (placebo 50%). Nausea, headache and sleepiness, and dyspnoea led to withdrawal of one child from nedocromil sodium and placebo treatments, respectively. Reports of sore throat and headache were marginally greater with the nedocromil sodium treatment. It is concluded that nedocromil sodium was both effective and safe in the treatment of asthma in children.