Long-latency stretch reflexes as co-ordinated functional responses in man.

1. Reflex activity in human arm muscles has been measured in response to torque perturbations around the elbow joint in the flexion-extension direction and/or the supination-pronation direction. Intramuscular fine-wire electrodes were used to record electromyographic (EMG) activity in the muscles. A pre-load was applied in the same direction as or in a different direction to the perturbation. The subjects were instructed to 'hold on', which means that they had to actively resist the perturbation without unduly co-activating their muscles. 2. The EMG activity showed segmented reflex responses with short-latency (25-50 ms) and long-latency (50-75 ms) components, followed by other bursts of activity which probably originated from the subject's voluntary or triggered reactions. 3. Motor units in m. triceps gave short-latency and long-latency responses to imposed elbow extension but only long-latency responses were seen to imposed pronation, which does not stretch m. triceps. Motor units in m. brachialis gave short-latency and long-latency excitatory (inhibitory) responses to imposed extension (flexion) torques. However, only long-latency inhibitory responses were observed to imposed pronation torques. Motor units in m. biceps gave short-latency and long-latency excitatory responses to imposed pronation torques. 4. These results show that the long-latency reflex cannot be the result of a simple feed-back mechanism that controls muscle length only. We argue that the long-latency reflex activity reflects the co-ordinated activation of muscles which is necessary for an adequate response. This hypothesis is supported by the fact that the distribution of long-latency reflex activity over muscles was found to be similar to the distribution of activation found during a voluntary exerted torque in the direction opposite to the applied perturbation.

Language development at the age of 3 years of infants malnourished in utero.

To evaluate if language testing might provide useful information about the developmental outcome at pre-school age of term infants malnourished in utero, a group of these infants was studied in combination with a group of normally grown term infants matched for age, sex, birth rank and social class. Both groups were free from significant neonatal morbidity and debilitating diseases. Intrauterine malnutrition was defined as underweight for gestational age and the presence of wasting to select those S.G.A. infants with easily recognizable signs of malnutrition at birth. The Reynell Developmental Language Scales were used to test language and the results were related to a separate assessment of behaviour and neurology. Both verbal comprehension and expressive language were significantly less developed in infants malnourished in utero. A firm relation was established between language delay and behaviour problems. It was concluded that language development can be used to assess the developmental progress of infants malnourished in utero if performed in combination with behaviour assessment. Many of these infants will benefit by speech therapy during behaviour therapy at pre-school age.

Neonatal morbidity of S.G.A. infants in relation to their nutritional status at birth.

46 consecutively born term infants with a birthweight less than or equal to 2.3 percentile for gestational age were divided into two groups according to their nutritional status at birth quantified by the ponderal index (100 x weight/lenght). Though all infants had a ponderal index below the 50th percentile, those with a ponderal index below the 3rd percentile (about half of the study group) were more frequently affected by asphyxia, hypoglycaemia, hypothermia, and hyperviscosity than their more proportionally grown counterparts. On this account the identification of disproportionally grown small-for-gestational age infants by using the ponderal index as a yardstick of the nutritional status at birth, is necessary because they constitute a high-risk group among small-for-gestational age infants.

Developmental aspects of subacute fetal distress: behaviour problems and neurological dysfunction.

A group of term infants malnourished in utero and classified as a subacute fetal distress at birth were followed up with a group of normally grown term infants matched for age, sex, birth rank and social class. Both groups were free from other perinatal morbidity and chronic diseases. At three years of age behaviour was studied using the behaviour screening questionnaire of Richman and Graham and a behaviour observation report, whereas neurological dysfunction was assessed according to the pro forma of Touwen. Both problematic behaviour and neurological dysfunction occurred more frequently in the subacute fetal distress group. Behaviour problems are comparable to neurological signs as indicators for brain dysfunction.

Skeletal maturity at birth and at the age of 3 years of infants malnourished in utero.

Twenty five term infants malnourished in utero and 25 matched controls were studied at birth and at 2 1/2-3 1/2 years of age. At birth the infants malnourished in utero had a significant retardation in skeletal maturity in comparison with the control group. At 2 1/2-3 1/2 years of age the average skeletal maturity of the intrauterine malnourished children approached that of the controls. However, those with a length below the national 10th centile still showed a retarded skeletal growth in comparison with those who had reached a length above the 10th centile for age.

Intra-uterine malnutrition and skeletal retardation.

In the subgroup of small-for-dates, indicated as intra-uterine malnourished infants, we made an attempt to correlate the degree of starvation and the degree of skeletal retardation. In 31 wasted infants (including 4 post-mature children) and 20 not wasted infants, the ponderal index (100 X W/L3) was determined and deviation from 'normal' calculated. A highly significant correlation was found between the degree of malnutrition (deviation of the ponderal index from normal) and the degree of skeletal retardation (in weeks). The skeletal retardation seems a useful parameter to determine the minimal duration of insufficient energy supply to the fetus.

Quantification of intrauterine malnutrition.

Small-for-gestational-age infants are a heterogeneous collection of growth-retarded infants. In the subgroup of intrauterine-malnourished infants an attempt is made to quantify the degree of malnutrition by postnatal measurements of length, weight and fat-fold thickness. In 48 clinically wasted and not-wasted term newborns, regardless of birth weight, the ponderal index of Rohrer (100 X W/L3) was determined and the deviation from 'normal' calculated. The deviations are correlated with fat-fold thickness and clinical diagnosis. A highly significant correlation gives support to the view that both ponderal index deviation from 'normal' and fat-fold thickness are useful parameters to quantify the effect of intrauterine malnutrition in newborns.

Acute lymphopenia, stress, and plasma cortisol.

Plasma cortisol levels were determined in 51 children on admission to hospital for a variety of acute illnesses which were associated with a lymphopenia, and again when the lymphocyte count had returned to normal. The ratio cortisol level/lymphocyte count was much higher in the acute phase of the illness than later when the lymphocyte count had returned to normal. It is concluded that the lymphocyte count is a useful means of detecting an acute stress condition, and the time of return of normal plasma cortisol levels.

Maternal anticonvulsants and perinatal risk.

According to data found in the literature, children born to epileptic mothers on anticonvulsant therapy have an increased perinatal mortality rate, namely 2-3 times the average. The congenital malformations attributed to anticonvulsant drugs cannot fully account for this high mortality rate. A case is described in which a severe bleeding disorder manifested itself in successive offspring. A discussion follows in which this defect in blood coagulation in the newborn and the role played by vitamin K is considered as representing an important and preventable cause of neonatal death and morbidity. Other features of the postnatal syndrome (CNS depression, congenital heart disease, withdrawal symptoms, anemia) are mentioned in the case report. Suggested preventative measures employing vitamin K, folic acid and vitamin D are briefly discussed.