Factors affecting physicians' decisions on caring for an incompetent elderly patient: an international study.

Objectives: To determine what treatment decisions physicians will make when faced with a hypothetical incompetent elderly patient with life-threatening gastrointestinal bleeding and to examine the relative importance of physician characteristics and factors (legal and ethical concerns, hospital costs, level of dementia, patient's age, physician's religion, patient's wishes and family's wishes) in making those decisions.

Design: Survey.

Setting: Family practice, medical and geriatrics rounds in academic medical centres and community hospitals in seven countries.

Modulation of human short latency reflexes between standing and walking.

Inhibition of the magnitude of soleus muscle homonymous (H) reflexes occurs in humans when walking, compared to standing. The current study asked, (1) was the task modulation of Ia reflexes limited to soleus muscle, (2) was there support for attributing a presynaptic source to the inhibition in humans and (3) did an oligosynaptic short latency reflex show similar task modulation? In 3 subjects, H reflexes were evoked in vastus medialis and soleus, at 4 levels of contraction in the target muscle, with constant stimulus intensity when walking and standing. The reflex magnitudes in both muscles were significantly inhibited during the contractions for walking, compared to standing.

Vibration insensitivity of a short latency reflex linking the lower leg and the active knee extensor muscles in humans.

The study indirectly investigated the afferent source of a human lower limb reflex that spans two joints and may link limb muscular activity during movement. Low threshold (motor nerve threshold (MT) to 1.6 MT) single, 1 msec, pulses were delivered to the common peroneal nerve at caput fibula.

Movement modulation of a short latency reflex linking the lower leg and the knee extensor muscles in humans.

Movement modulation of a heteronymous short latency spinal reflex was investigated with transcutaneous, low threshold, stimuli to the common peroneal nerve, during leg pedalling in humans. Electromyographic (EMG) electrodes on the skin over the quadriceps muscles revealed an excitatory response at a minimum latency of 22.8 msec.

Aging of human segmental oligosynaptic reflexes for control of leg movement.

A heteronymous group I oligosynaptic reflex from the common peroneal nerve to vastus medialis muscle was compared with a group I homonymous monosynaptic reflex to soleus, using electrical stimulation of peripheral nerve trunks in two groups of healthy men, mean ages 22 and 65 years. The oligosynaptic reflex was still elicitable with age, its magnitude decreasing similarly to the monosynaptic reflex. A further group of older subjects, mean age 75 years, showed similar results.

Effect of knee joint angle on a heteronymous Ib reflex in the human lower limb.

Altered efficacy, from change in receptor discharge with different positions of the knee, was investigated in a heteronymous Ib reflex of the human leg. The electrical stimulus was low threshold, to the common peroneal nerve. The divergence of the group I afferents was studied in the electromyograms (EMGs) of ipsilateral and contralateral thigh muscles.

A technique for electrically induced perturbation of rhythmic leg movement.

The paper describes electrical circuitry which replaces a mechanical brake, for perturbation of the contractile load of the legs during pedalling. The turning flywheel of an ergometer is connected to an alternator, with the electrical load provided by a power resistor connected across the output terminals. A 12-V battery provides the field current.

Anticonvulsant-induced marrow suppression and immune thrombocytopenia.

Phenytoin and carbamazepine are rarely associated with serious hematologic side effects but can include impairment of either humoral or cell-mediated immunity. We describe a patient who developed severe granulocytopenia while taking phenytoin. The phenytoin was replaced by carbamazepine and the patient subsequently developed erythroid hypoplasia, neutropenia and persistent thrombocytopenia.

Response synergies over a single leg when it is perturbed during the complex rhythmic movement of pedalling.

Previous studies report that perturbing the posture of humans evokes specific patterns of muscular synergies in the legs. This study investigated the pattern of muscular responses of a whole limb when it was rapidly perturbed in the phase of extending during stationary pedalling. Subjects were instructed to resist.

Human group I excitatory projections from ankle dorsiflexors to quadriceps muscle.

A short latency projection of group I afferent fibers from ankle dorsiflexors to knee extensor muscles has been categorized as species specific to humans. However, the effects of the pathway have only been inferred from conditioning homonymous reflexes in relaxed muscle. This study focused directly on the responses evoked in the electromyogram of the heteronymous muscles when active, in two experiments.

Magnitude of the H reflex of the soleus substantially exceeds the myotatic response from rapid dorsiflexion of the ankle joint.

We compared the magnitude of short-latency EMG responses in the soleus after electrical stimulation and after muscle stretch. The peak to peak amplitudes and areas of such stretch-evoked responses, following initial rotation velocities to 200 degrees/s, did not extend beyond the lower part of the H reflex range (evoked electrically). The disparity suggests caution in the use of electrical stimulation of group 1 afferent fibers when a study is to be made of normal human movement.

Locomotor limb synergism through short latency afferent links.

Reports of facilitation of lower limb synergists through afferent stimulation in resting humans lead to study of short latency reflex responses during activity of the legs. Four synergistic muscles of the right leg were examined following electrical stimulation of low threshold afferents of the posterior tibial (PTN) and femoral (FN) nerves. Four males cycled on an ergometer with pedals modified to measure the force applied.

Syringomyelia: a clinical review of 75 cases.

Records of 75 patients with syringomyelia are reviewed. Their clinical course fell into one of three main groups: (1) those with a long history of a steadily progressive disability; (2) those with a long history but little or no progression of their disability; and (3) those with a short, fairly rapid downhill course.On the basis of this study, x-ray therapy seems to be of little value in the treatment of this disease.