Victor Dubowitz

Clinical assessment of gestational age in the newborn infant

A scoring system for gestational age, based on 10 neurologic and 11 “external” criteria, has been applied to 167 newborn infants. The “external” score gave a better correlation with gestation than did the neurologic score, but the combined total score was better than either alone. The correlation coefficient for the total score against gestation was 0.93. The error of prediction of a single score was 1.02 weeks and of the average of two independent assessments was 0.7 weeks. The method gives consistent results within the first 5 days and is equally reliable in the first 24 hours of life. This scoring system is more objective and reproducible than trying to guess gestational age on the presence or absence of individual signs.

The development of visual function in normal and neurologically abnormal preterm and fullterm infants.

Pattern preference for four different pairs of patterns, and visual acuity based on the ability to distinguish black and white stripes of different widths, were compared in neurologically normal and abnormal preterm infants at 36 and 40 weeks postmenstrual age and in normal and abnormal fullterm infants in the newborn period and again at four and six weeks of age. The study aimed to chart the maturation process of these visual functions in the neonatal period and to assess their predictive value in the neurologically abnormal infant. Part I of the study deals with the normal infant and Part II with the abnormal infant.

Morphological studies on normal and diseased human muscle in culture.

Abstract Normal and diseased human muscle, obtained by biopsy, has been successfully grown in tissue culture and has differentiated through multinucleate myoblast and myotube stages and has also developed cross-striations. Comparative studies have been made of the normal and diseased muscle in vitro to try to detect changes comparable to those occurring in the diseased muscle in vivo. The lengths and breadths of multinucleate (differentiated) cells have been measured, the number of nuclei counted and the results subjected to statistical analysis. No significant differences have been found between the normal and diseased muscle in culture. It is possible that diseased muscle may revert to a normal state when cultured.

Histochemical studies on normal and diseased human and chick muscle in tissue culture

Abstract Adult human muscle in tissue culture gives rise to myotubes which show strong NADH-TR activity, weak phosphorylase activity, strong myosin ATPase activity, and moderate levels of PAS-positive material. No “fibre types” were observed. No difference could be detected in the histochemical profile of myotubes derived from control and diseased muscle in culture. It is possible that histochemical abnormalities in cultured human muscle may only be observed when innervated and therefore more fully differentiated. Embryonic chick muscle in culture gives myotubes that have strong phosphorylase activity, moderate NADH-TR activity, strong myosin ATPase activity and moderate levels of PAS-positive material, suggesting species-specific determinants of enzymatic differentiation.

Postnatal maturation of peripheral nervesin preterm and full-term infants*

The conduction velocity of the ulnar and posterior tibial nerves was measured serially during the first year of life in normal preterm and full-term infants. At birth the preterm infants had significantly slower velocities than did the full-term infants. The conduction velocities of the ulnar and posterior tibial nerves remained significantly slower until 9 months and 3 months of age, respectively. When related to postconceptional age, however, the conduction velocities in preterm infants were slower than those of full-term infants only at 40 weeks; from 44 weeks onward there was no significant difference in the mean velocities. The rate of maturation of the peripheral nerves of preterm infants is thus retarded for only a few weeks after birth; subsequently it is the same as that of full-term infants of similar postconceptional age.

DIFFERENTIATION OF DISEASED HUMAN MUSCLE IN CULTURE

Diseased human muscle is capable of differentiation in culture in the same way as normal muscle.

Quantitative electromyography: carrier detection in Duchenne type muscular dystrophy using a new automatic technique

An automated method of quantitating small electromyographic changes, based on the ratio of action potential duration to the number of phases per potential, was applied to carriers of X-linked Duchenne type muscular dystrophy. The ratio was found to be significantly raised in a proportion of these cases.

Assessment of Gestational Age in Newborn Infants: Nerve Conduction Velocity versus Maturity Score

The gestational age of 75 newborn infants was assessed both by measuring the uhar and posterior tibial conduction velocities and by obtaining a maturity score based on clinical criteria. There was a good correlation between the two estimates. The maturity score was slightly more accurate than the conduction velocity in predicting the gestational age.

The Floppy Infant—A Practical Approach to Classification

A practical classification of the floppy infant into paralytic and non‐paralytic disorders is suggested. Further subdivision is based on the frequency of various underlying causes. The nomenclature is simplified, and obselete and obsolescent terminology has been discarded.

Ultrastructure of muscle in infantile spinal muscular atrophy

Abstract An electron-microscopic study of muscle biopsies of the rectus femoris from 3 cases of severe infantile spinal muscular atrophy (Werdnig-Hoffmann disease) showed extensive changes in the myofibrils, with degeneration and disappearance of myofilaments; dilatation and focal proliferation of the sarcotubular system; and degeneration of mitochondria. Changes were also observed in the plasma and nuclear membranes. One case showed unusual tubular structures thought to be abnormal mitochondria. The features are similar to those found in other forms of neuropathy and in experimental denervation.