Warping of cross sections in the torsion of long bones with internal fracture fixation plates

Torsion of noncircular beams results in warping of each cross section. When noncircular cross sections are constrained to remain plane, the resulting shear stress distribution is different from what Saint Venant torsion (with warping) would predict. This has practical implications to the stress analysis of plated long bones subjected to torsional loadings. Analyses in which warping is not allowed predict incorrect stress fields in the plate and bone and overpredict the amount of stress shielding associated with fracture plate fixation.     

Compressed collagen sponges as gastroretentive dosage forms: in vitro and in vivo studies.

The objective of the present investigations was to develop oblong tablets which expand after contact with gastrointestinal fluids within a few minutes to a length of 4-6 cm and which should remain in the stomach for a prolonged period of time due to their size. The tablets were prepared from riboflavin-containing collagen sponges using a computer controlled single punch tablet machine. The collagen material was compressed to oblong tablets with dimensions of 3.5 mm x 9 mm x 18 mm. In vitro investigations were carried out to characterise drug release. The model drug riboflavin was released from the collagen tablets over 12h. The gastrointestinal retention time of the new dosage form was indirectly estimated by determining the duration of riboflavin excretion after oral intake of the tablet. A crossover in vivo study with 12 healthy male and female subjects was performed. The renal excretion of riboflavin was measured after oral administration of collagen tablets and small sustained release hydrocolloid tablets as reference preparation. The amount of riboflavin excreted into the urine was enhanced after administration of the expanding collagen tablets in comparison with the hydrocolloid tablets. The differences were statistically significant after 5, 6, 8, 9, 10 and 12 h.     

Long-term effects of physical exercise on working capacity and pulmonary function in cystic fibrosis

Seven patients with cystic fibrosis aged 6 to 20 were enrolled for 30 months in a daily exercise program. After 12 months conventional chest physiotherapy was withdrawn. Patients with low initial Shwachman scores improved as regards maximal working capacity. Spirometric data and volume of trapped gas indicated opening of closed airways. We suggest that physical exercise in general should be the basis of pulmonary therapy in cystic fibrosis. Other forms of physiotherapy are advisable when hard physical exercise is not feasible.     

Labially displaced ectopically erupting maxillary permanent canine: interceptive treatment and long-term results.

This case report demonstrates how extracting a maxillary deciduous canine affects the eruption path of a labially displaced ectopically erupting permanent canine. A long-term follow-up is presented, and the biologic mechanisms are discussed.     

Innervation of the child urinary bladder

Muscle strips from the fundus, trigonum and distal ureters obtained from children at operations for vesico-ureteric reflux were studied using histochemical and immunohistochemical methods, and electrical nerve stimulation in an organ bath. A rich supply of cholinergic nerves was found and despite a partial atropine resistance the neurophysiological experiments indicated that the transmitter causing contraction of the detrusor muscle is acetylcholine. Imipramine, which is used in the treatment of enuresis, had no anticholinergic effect on the bladder in the doses used clinically. The adrenergic innervation was very sparse except around the ureter orifices. No contractile alpha-adrenoceptors could be detected but beta receptor mediated relaxation was found, which was neither of the beta 1 nor beta 2 type. A third type of beta receptor is postulated. Peptidergic nerves containing vasoactive intestinal peptide, VIP, were demonstrated in a few nerve terminals running along bundles of smooth muscle. No nerves containing enkephaline, somatostatine or substance P were found. VIP affected the detrusor muscle indicating a possible role as a modulator of transmitter action, while substance P had no effect. The anticholinergic and calcium antagonistic drug terodiline inhibited all muscle activity, whether it was induced by nerve stimulation, cholinergic drugs or a potassium rich solution, making it suitable for treatment of diurnal enuresis.     

Early spontaneous hematoma in cerebral infarct: is primary cerebral hemorrhage overdiagnosed?

We identified 15 patients (63 +/- 8 years) in whom CT showed no bleeding within 6 hours of stroke onset but showed ganglionic or lobar hemorrhage less than 18 hours later, without visible underlying infarct (early spontaneous intra-infarct hematoma [ESIH]). No patient had antithrombotic therapy or a coagulation disorder, but eight had hypertension. The second CT was prompted by rapid worsening (in 10) or because the first CT was not available (in five). Prior transient ischemic attacks, silent infarcts on CT, and a potential cardiac source of embolism were more common in patients with ESIH than in 200 patients with primary cerebral hemorrhage (PCH) admitted during the same period. Distal occlusions were present in four of five patients who underwent intracranial studies within the first 2 days. Most of these patients probably had embolism with early and extensive bleeding in the ischemic area. Our findings suggest that ESIH may be under-recognized, while PCH may be overdiagnosed.