Musculoskeletal modelling in determining the effect of botulinum toxin on the hamstrings of patients with crouch gait

This study aimed to determine the effect of hamstring botulinum toxin A (Btx-A) injection in 10 children with crouch gait in terms of changes in muscle length and lower-limb kinematics. Before Btx-A injection limb kinematics were recorded. Maximum hamstring lengths and excursions were calculated by computer modelling of the lower limb. Data were compared with the averaged hamstring lengths of 10 control children. Hamstrings were denned as short if their length was shorter than the average maximum length minus one standard deviation. Gait analysis was repeated 2 weeks after isolated hamstring Btx-A injection. Pre- and postinjection kinematic data and muscle lengths were then compared. Four of 18 injected limbs in three subjects had short medial hamstring before injection, none of the subjects had short lateral hamstrings. Muscle excursion was significantly reduced in the short and adequate maximum muscle length groups. A significant increase in the semimembranosus and semitendinosus length in all of the injected limbs was noted. Only in the short muscle group was a significant increase in muscle excursion observed. Knee extension improved by 13° in the adequate muscle length group and by 15.6° in the short muscle length group. Pelvic tilt and hip flexion increased in both groups non-significantly. Average walking speed postinjection increased from 0.60 ms^-1 to 0.71 ms^-1. Short hamstrings are over-diagnosed in crouch gait. Hamstring Btx-A injection in patients with crouch gait produces significant, repeatable muscle lengthening and improved ambulatory function.     

Nontransferrin-bound iron in plasma from hemochromatosis patients: effect of phlebotomy therapy

Plasma from patients with iron overload resulting from idiopathic hemochromatosis contains nontransferrin-bound iron, measurable by the bleomycin, assay. During venesection therapy, the concentration of bleomycin iron declines in a way highly correlated with plasma ferritin concentrations. Even when patients had been venesected to give very low total plasma iron concentrations and high transferrin iron-binding capacity, bleomycin-detectable iron was still present at low concentrations. Bleomycin-detectable iron can stimulate damaging free radical reactions, and its persistence in plasma even after prolonged venesection might contribute to the tissue damage that results from iron overload.     

Computed tomography of the thorax

Computed tomography (CT) provides a valuable new perspective in assessing abnormalities of the thorax. In the patient with a mediastinal mass or widening detected by plain chest radiography, a definitive diagnosis is sometimes possible which would not be obtainable by conventional noninvasive radiological techniques. In certain clinical situations, CT is a highly sensitive modality for examining the lungs. The proved and potential clinical uses of CT in solving diagnostic problems of the thorax are discussed.     

Arsenic intoxication as a cause of megaloblastic anemia

We have described a case of chronic arsenic intoxication associated with pancytopenia and megaloblastic erythropoiesis. The patient had the typical laboratory manifestations of effective erythorpoiesis due to a megaloblastic process, including macroovalocytes, mild pancytopenia, low reticulocyte index, increased marrow cellularity with erythroid hyperplasia, and morphologic evidence of megaloblastic maturation in the marrow. The patient's serum folate and vitamin B12 were normal, and the anemia regressed without therapy. Our case suggests that the combination of megaloblastosis with normoblastic or megaloblastic karyorrhexis,should raise the suspicion of arsenic intoxication in the mind of the observer. In addition, arsenic should be added to the list of agents causing a reversible megaloblastic anemia.