Neuraminidase activity in the mucolipidoses (types I,II and III) and the cherry-red spot myoclonus syndrome

Two neuraminidase (EC 3.2.1.18) components, A and B, were distinguished in cultured skin fibroblasts on the basis of thermolability at 37°C. The more labile component (A) $\text{t}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{= 4.7–5.3}\text{min}$ at 37°C, comprises 66–90% of total neuraminidase activity when determined using sodium ($\text{4-}\text{methylumbelliferyl}\text{-α-}\text{d}\text{-N-}\text{acetylneuraminate}$) (MU-α-N) as substrate. Activity was assayed at 0°C for 18 h instead of 37°C to fully determine both thermolabile and thermostable components. Diminished activity was noted in cultured fibroblasts from mucolipidoses I, II and III (MLI, MLII, MLIII) and the cherry-red spot myoclonus syndrome (CRSM) patients when assayed at both 0 and 37°C with either MU-α-N or each of a series of α(2 → 3)- and α(2 → 6)-linked N-acetylneuraminyl-oligosaccharides. Increased sensitivity and rapidity of analyses were achieved using MU-α-N as substrate in determining neuraminidase activity. Results from two obligate heterozygote MLI cell lines (14.5 and 8.0% of control activity) indicate that the MU-α-N substrate could be useful for heterozygote detection.     

Lipoamide dehydrogenase in cultured human skin fibroblasts

Lipoamide dehydrogenase was identified in cultured skin fibroblasts of normal individuals and patients with Friedreich's ataxia. The optimum conditions for its assay were defined. Data disclosed a normal range of 36--122 mumol/min/mg protein in control fibroblasts and 61--112 mumol/min/mg protein in patients fibroblasts. Numerous precautions should be taken in handling fibroblast cultures for lipoamide dehydrogenase determination.     

PART 2: Practice and research recommendations for quality developmental care in the NICU

Developmental care interventions, which may promote preterm infant's neurodevelopment during the hospitalization in the Neonatal Intensive Care Unit, should be implemented and integrated to care delivered by nurses, other healthcare professionals, and parents. These interventions may have an impact on the preterm infants' developing brain and optimize their short and long-term health outcomes. Based on a previous narrative overview, more high-quality research is still needed in this field. Nevertheless, best practice of developmental care can still be recommended to improve today's neonatal clinical practice. The aim of this article is to provide both practice and research recommendations according to the seven categories of developmental care interventions in the neonatal intensive care unit: family-centered care, sleep protection, assessment and management of pain, infant positioning, optimized infant-driven feeding, administration of human milk, and control of the environmental light and noise.     

Congenital insensitivity to pain and the "morphine-like" analgesic system.

Congenital insensitivity to pain remains without a satisfactory physiopathological explanation. In an electrophysiological study on a nociceptive flexion reflex of the lower limb, the effects of naloxone and of placebo were compared in 8 normal subjects and in a patient with congenital insensitivity to pain. In normal subjects, no significant change in the reflex threshold was observed with naloxone or with placebo. In contrast, two electrophysiological abnormalities characterized the patient: (1) spontaneous elevation in the nociceptive reflex threshold of 350% as compared to control, and (2) a large (67%) and rapid (2--3 min) fall of this threshold for about 10 min following the administration of naloxone. These results raise the problem of the relationship between congenital insensitivity to pain and an hyperactivity of a naturally occurring "morphine-like" pain-inhibitory system.