Three dimensional inertial sensing of foot movements for automatic tuning of a two-channel implantable drop-foot stimulator.

A three dimensional inertial sensing system for measuring foot movements during gait is proposed and tested. It can form the basis for an automated tuning system for a two-channel implantable drop-foot stimulator. The foot orientation and position during the swing phase of gait can be reconstructed on the basis of three-dimensional measurement of acceleration and angular velocity, using initial and final conditions during mid-stance. The foot movements during gait of one stroke person using the implanted two-channel stimulator were evaluated for several combinations of stimulation parameters for both channels. The reconstructed foot movements during gait in this person indicated that the channel stimulating the deep peroneal nerve contributes mainly to dorsiflexion and provides some reduction of inversion seen without stimulation, while the channel activating the superficial peroneal nerve mainly provides additional reduction of inversion. This agrees with anatomical knowledge about the function of the muscles activated by both branches of the peroneal nerve. The inertial sensor method is expected to be useful for the clinical evaluation of foot movements during gait supported by the two-channel drop-foot stimulator. Furthermore, it is expected to be applicable for the automated balancing of the two stimulation channels to ensure optimal support of gait.

Allelic loss of the short arm of chromosome 4 in neuroblastoma suggests a novel tumour suppressor gene locus.

Neuroblastoma is a childhood neural crest tumour, genetically characterized by frequent deletions of the short arm of chromosome 1 and amplification of N-myc. Here we report the first evidence for a neuroblastoma tumour suppressor locus on 4pter. Cytogenetically we demonstrated rearrangements of 4p in 7 out of 26 evaluable tumours (27%). Subsequent analysis of loss of heterozygosity (LOH) by Southern blotting revealed allelic loss of 4p in 16/82 (19.5%) informative neuroblastomas. Taken together cytogenetic and Southern blot analyses showed loss of 4p in 20/86 neuroblastomas analysed (23%). The common deleted region was bordered by the probe D4S123 and encompassed the distal 34 cM of 4p. We found no evidence for genomic imprinting of the 4p locus as the 4p alleles lost in the tumours were of random maternal and paternal origin. LOH4p was found at all disease stages and in every age group. Furthermore LOH4p was present both in cases with and without LOH1p and amplification of N-myc.

Effects of cisplatin on parathyroid hormone- and human lung tumor-induced bone resorption.

We have previously shown that dichlorodiamine platinum (DDP), or cisplatin, a cancer chemotherapeutic agent, is effective in the treatment of malignancy-associated hypercalcemia. In the present studies, we evaluated its effects on bovine parathyroid hormone (PTH)- or tumor-induced bone resorption in vitro in the neonatal mouse calvarial bone resorption assay. PTH alone or tumor extract (TE) of a human squamous cell lung cancer alone caused a significant increase in the bone resorption and in the number of osteoclasts in the calvaria. The addition of 3 and 10 micrograms/ml DDP inhibited the PTH- or TE-induced bone resorption. Lower doses of 1 and 2 micrograms/ml DDP, although not effective in inhibiting the PTH-induced bone resorption, were effective in lowering the TE-induced bone resorption. The number of osteoclasts was also reduced by DDP treatment. We therefore conclude that DDP is effective in the treatment of malignancy-associated hypercalcemia by virtue of its inhibitory effects on osteoclast numbers and on bone resorption.

Experimental intrahepatic portacaval anastomosis: use of expandable Gianturco stents.

Original Gianturco expandable stents and their modifications were used to create an experimental intrahepatic portacaval anastomosis (EIPCA) in 30 young domestic swine without portal hypertension. The study focused on the design of a suitable stent, the technique of its application, and the evaluation of short-term patency of the EIPCA. A stent with a 2.5-cm-long body and wire skirts on both ends was most suitable for EIPCA creation. Well-positioned stents shunted most of the portal blood in the inferior vena cava circulation and remained patent for 4-6 weeks. Ingrowth of liver parenchyma and abundant proliferation of the intima and connective tissue inside the stent lumen in these rapidly growing animals gradually decreased EIPCA patency, and thrombus formation with diminished blood flow closed them completely.

Iopamidol arteriography: discomfort and pain.

A double-blind, randomized study was performed to compare discomfort and pain associated with the use of iopamidol and Hypaque (diatrizoate sodium and diatrizoate meglumine) during iliofemoral runoff arteriography in 33 patients. Iopamidol caused substantially less discomfort and pain. The evaluation was helped by audiotaping the study and comparing patients' vocal responses to injections of these materials.

The value of protamine following heparin-covered angiography: double-blind placebo-controlled study.

Routine postprocedural administration of protamine sulfate has been advocated to offset the anticoagulant effect of prophylactic heparin given during transfemoral catheter angiography. The value of protamine is shown in a double-blind, randomized, placebo controlled series of 257 cases.

Retrograde pancreatic venography after reduction of the arterial visceral flow: an experimental study.

To evaluate techniques for retrograde pancreatic venography similar to epinephrine renal venography, 35 dogs had transjugular portography before and after the infusion of various doses of vasopressin systemically or selectively into the superior mesenteric and celiac arteries, or after occlusion of the distal thoracic aorta. Increased filling of the peripheral portal branches resulted, but none of the techniques provided diagnostically useful enhanced pancreatic visualization.

Experimental carotid aneurysms: I. Simple surgical production and radiographic evaluation.

Using simple surgical techniques, experimental carotid aneurysms are created which simulate some types of human berry aneurysms, both in hemodynamic and radiographic behavior. End to side anastomoses of an external jugular vein graft to the common carotid artery can be carried out by radiologic personnel with no formal surgical training. Factors which cause the aneurysms to fail and fill with clot are infection, incorporation of venous valves into the aneurysm sac, poor suturing technique, and perhaps a sac too large in comparison with its neck. The models are studied and followed by percutaneous catheter angiography, and show the swirling flow seen in clinical practice. These models may be used to study and refine percutaneous catheter occlusive techniques.