Distinguishing benign and malignant melanocytic lesions with the AgNOR method.

A silver staining technique has recently been devised to aid in the differentiation between benign and malignant melanocytic lesions. This study showed a statistically significant difference between the staining of silver-nucleolar organizer regions (AgNORs) in melanocytic nevi and that of AgNORs in malignant melanomas.

An equilibrium-point model for fast, single-joint movement: II. Similarity of single-joint isometric and isotonic descending commands.

The model for isotonic movements introduced in the preceding article in this issue is used to account for isometric contractions. Isotonic movements and isometric contractions are analyzed as consequences of one motor program acting under different peripheral conditions. Differences in isotonic and isometric EMG patterns are analyzed theoretically.

An equilibrium-point model for fast, single-joint movement: I. Emergence of strategy-dependent EMG patterns.

We describe a model for the regulation of fast, single-joint movements, based on the equilibrium-point hypothesis. Limb movement follows constant rate shifts of independently regulated neuromuscular variables. The independently regulated variables are tentatively identified as thresholds of a length sensitive reflex for each of the participating muscles.

Gender differences in age effect on brain atrophy measured by magnetic resonance imaging.

A prospective sample of 69 healthy adults, age range 18-80 years, was studied with magnetic resonance imaging scans (T2 weighted, 5 mm thick) of the entire cranium. Volumes were obtained by a segmentation algorithm that uses proton density and T2 pixel values to correct field inhomogeneities ("shading"). Average (+/- SD) brain volume, excluding cerebellum, was 1090.

Prospective follow-up for malignant melanoma in patients with atypical-mole (dysplastic-nevus) syndrome.

A total of 357 white patients who had melanocytic nevi that fulfilled the clinical criteria for the "classic" atypical-mole (dysplastic-nevus) syndrome (100 or more melanocytic nevi; one or more melanocytic nevi 8 mm or larger in diameter; and, one or more melanocytic nevi with atypical features) were followed for the development of cutaneous malignant melanomas. Seventeen patients (4.8%) developed malignant melanomas during an average follow-up period of 49 months.

Reconstruction of shifting elbow joint compliant characteristics during fast and slow movements.

The purpose of this study was to experimentally investigate the applicability of the equilibrium-point hypothesis to the dynamics of single-joint movements. Subjects were trained to perform relatively slow (movement time 600-1000 ms) or fast (movement time 200-300 ms) single-joint elbow flexion movements against a constant extending torque bias. They were instructed to reproduce the same time pattern of central motor command for a series of movements when the external torque could slowly and unpredictably increase, decrease, or remain constant.

Delirium in the medically ill elderly: operationalizing the DSM-III criteria.

This prospective study determined the incidence and prevalence of delirium in 235 consecutive subjects over age 70 admitted to a general medicine hospital service. The DSM-III criteria for delirium were operationalized. Using accepted screening procedures, patients were referred for evaluation by a psychiatrist who determined whether delirium was present by applying explicit operational definitions to each of the DSM-III criteria.

Behavioral pathway to evolutionary change.

The extreme malleability or plasticity of cells early in their development is mirrored to a certain, if lesser, degree in the psychological, behavioral, and neural functioning of developing organisms. The early developmental adaptability of organisms has significance for our understanding of evolution. It is the purpose of the present article to make a case for the extra-genetic or, better, the supra-genetic developmental basis of evolutionary change through the genesis of novel behavioral phenotypes.

Relativistic effects in single-joint voluntary movements.

We assume that there is an upper limit for the rate of change of controlled variables in the motor control system. Superposition of two single-joint motor programs can lead to a distortion of their simple algebraic summation similar to relativistic Lorenz transformations. Experiments were carried out with the subjects performing fast oscillatory elbow movements on the background of a smooth elbow flexion.

Neophenogenesis: a developmental theory of phenotypic evolution.

An important task for evolutionary biology is to explain how phenotypes change over evolutionary time. Neo-Darwinian theory explains phenotypic change as the outcome of genetic change brought about by natural selection. In the neo-Darwinian account, genetic change is primary; phenotypic change is a secondary outcome that is often given no explicit consideration at all.

Organizing principles for single-joint movements. IV. Implications for isometric contractions.

1. Normal human subjects made isometric pulse and step contractions about the elbow to visually defined target torques of different amplitudes and at different rates. We measured joint torque and electromyograms (EMG) from two agonist and two antagonist muscles.

Auditory basis of maternal attachment in ducklings (Anas platyrhynchos) under simulated naturalistic imprinting conditions.

The presence of broodmates during the imprinting process results in peer imprinting that interrupts a visually mediated maternal attachment. We sought to determine the conditions in which group-trained mallard ducklings (Anas platyrhynchos) acquire a maternal attachment. At 48 hr of age, ducklings were allowed to follow a vocal, stuffed mallard hen individually or in groups of 4.

Using DSM-III criteria to diagnose delirium in elderly general medical patients.

Studies of delirium in general medical populations have used criteria for delirium different from current DSM-III or DSM-IIIR criteria of the American Psychiatric Association, or have used DSM-III or DSM-IIIR criteria without operationalizing the components of these criteria. Therefore this prospective study was conducted to establish an approach to operationalizing DSM-III criteria and to determine the incidence and prevalence of delirium. Two hundred thirty-five consecutive subjects age 70 and over admitted to general medicine underwent daily standardized screening.

Sleep disorders and their management. Special considerations in the elderly.

Complaints of insomnia and disordered sleep are pervasive among the elderly, and reduced total sleep time and changes in sleep architecture are considered to be normal in the aging process. Additionally, numerous medical and psychiatric disorders that are highly prevalent in the geriatric population are known to affect sleep adversely. Epidemiologic data indicate that at least 5 million older adults suffer severe disorders of sleep and that most people with severe insomnia receive no treatment for this troubling symptom.

Organizing principles for single joint movements. III. Speed-insensitive strategy as a default.

1. Human subjects made discrete elbow flexions in a horizontal plane over different distances, from a stationary initial position to a visually defined stationary target 9 degrees wide. We measured joint angle, acceleration, and electromyograms (EMGs) from two agonist and two antagonist muscles.

Effects of intrathecal baclofen on voluntary motor control in spastic paresis.

Intrathecal baclofen injections were given to six patients with long-standing spastic paresis resistant to any nondestructive treatment, including oral baclofen. Attempts by the patients at voluntary muscle activation before intrathecal administration of baclofen led to considerable uncontrolled coactivation of antagonist and distant muscles. After the injection, dramatic suppression of the spastic signs was accompanied by more selective voluntary muscle activation.

Reflex responses to ankle perturbations during electrical stimulation of muscle: 1. Measurement techniques and preliminary examples.

Electrical stimulation of muscle has been proposed as a technique to restore function to paralyzed muscles. But, from a control stand-point, little is known about how such artificial activation interacts with the still intact spinal reflex loops. We have developed instrumentation to measure and compare ankle compliance and muscle EMG activity when the ankle is subjected to perturbations in torque or angular position from bias positions that are achieved volitionally or via electrical muscle stimulation.

Compliant characteristics of single joints: preservation of equifinality with phasic reactions.

Electromyograms (EMGs) of elbow flexors and extensors, elbow joint angle and torque were recorded in healthy subjects in the "do not react voluntarily" paradigm. Random loading and unloading torque perturbations of different rise times (Tr) were applied. Perturbations with Tr less than 300 ms evoke a phasic increase (in case of loading) or decrease (in case of unloading) in the flexor EMGs.

Organizing principles for single-joint movements. II. A speed-sensitive strategy.

1. Normal human subjects made discrete flexions of the elbow over a fixed distance in the horizontal plane from a stationary initial position to a visually defined target. We measured joint angle, acceleration, and electromyograms (EMGs) from two agonist and two antagonist muscles.

Organizing principles for single-joint movements. I. A speed-insensitive strategy.

1. Normal human subjects made discrete elbow flexions and extensions in the horizontal plane from a stationary initial position to visually defined targets at different distances with a constant inertial load or made flexions to a visually defined target with different inertial loads. We measured joint angle, acceleration, and electromyograms (EMGs) from two agonist and two antagonist muscles.

Maternal and peer imprinting in mallard ducklings under experimentally simulated natural social conditions.

Previous studies revealed that if socially reared mallard ducklings actively follow a stuffed mallard (Anas platyrhynchos) hen, they later show a visual preference for the familiar mallard hen over an unfamiliar redhead (Aythya americana) hen. The present study determined that the experience of actively following the hen is essential to the induction of a visually controlled, species-typical, maternal preference. Domestic mallard ducklings that had not been given the opportunity to follow the mallard hen were "passively" reared in social groups consisting of a stuffed mallard hen and seven same-aged siblings for either 24, 48, or 72 hr after hatching.

Intrathecal baclofen for severe spinal spasticity.

We studied the effect of the intrathecal infusion of baclofen, an agonist of gamma-aminobutyric acid, on abnormal muscle tone and spasms associated with spinal spasticity, in a randomized double-blind crossover study. Twenty patients with spinal spasticity caused by multiple sclerosis or spinal-cord injury who had had no response to treatment with oral baclofen received an intrathecal infusion of baclofen or saline for three days. The infusions were administered by means of a programmable pump implanted in the lumbar subarachnoid space.

Short-term effects of intrathecal baclofen in spasticity.

Six patients with long-lasting spasticity resistant to different drug therapies including oral baclofen received a bolus injection of lumbar intrathecal baclofen. Electromyographic (EMG) reactions of leg muscles (soleus, tibialis anterior, quadriceps, and hamstrings) to standard stimuli and during attempts at voluntary activation were recorded before the drug injection and up to 3 h after the injection. Responses to joint movements, H-reflexes, ankle clonus, and defensive reactions were noticeably suppressed within 30-45 min after the injection and had practically disappeared after 2 h.