Hexachlorophene encephalopathy

Goitre and hypothyroidism in the newborn after cutaneous absorption of iodine

Iodine goitre and hypothyroidism in 5 newborn infants in an intensive care unit were induced by cutaneous absorption of iodine, after numerous skin applications of iodine alcohol. The infant's skin permeability allows severe iodine overloading of the thyroid, resulting in goitre and hypothyroidism. Ioduria should always be sought in a newborn infant showing hypothyroidism. Iodine should not be used as a skin disinfectant in young infants.

Studies on hexachlorophene-induced myelin lesions in the trigeminal root transitional region in developing and adult mice

Hexachlorophene (HCP)-induced intramyelinic vacuolation was studied in the transitional region of the trigeminal root of suckling and adult mice. HCP produced an extensive vacuolation in the central compartment of the region in both suckling and adult mice, while in the peripheral compartment myelin lesions were only seen in mice less than 16 days of age. Gas chromatographic measurements showed that in suckling mice the blood concentration of HCP decreased with age, apparently reflecting a faster elimination of HCP from the blood. By substantially increasing the HCP dose, higher blood concentrations were obtained in adult than less the 16-day-old mice; in spite of this, PNS myelin changes occurred only in the latter. Thus, by observing the HCP effect on the transitional region, where CNS and PNS directly meet, it is concluded that CNS of both suckling and adult mice is more severely effected by HCP than PNS, and that the reaction of the PNS myelin is age-dependent during the period of myelinogenesis; it is particularly vulnerable to a cytotoxic edema inducing substance.

Endoneurial pressure in hexachlorophene neuropathy

Increased endoneurial pressure of up to 17.0 cm H2O was recorded in the peripheral nerves of rats fed hexachlorophene in their laboratory diet. The pressure was measured using a micropressure transducer developed for recording pressure in the microcirculation. The results were correlated with morphologic findings. Teased nerve fibers and araldite-embedded specimens of hexachlorophene damaged sciatic nerve revealed the characteristic severe intramyelinic edema due to splits in the minor dense lines of compact myelin giving rise to wide interlamellar spaces as shown in previous studies. The endoneurial pressure of rats exposed to hexachlorophene for 11 days and subsequently fed a normal diet returned to normal (0.2-3.0 cm H2O) after 12 days, and morphologic examination showed few residual abnormalities. Prolonged exposure to hexachlorophene for up to 4 weeks caused widespread axonal degeneration in addition to intramyelinic edema. Animals treated with hexachlorophene for 21 days followed by a normal diet for 14 days showed degenerated axons, phagocytosis of myelin as well as interstitial edema and elevated endoneurial pressure. It is suggested that axonal degeneration in hexachlorophene neuropathy is caused by increased endoneurial pressure.

Accidental percutaneous hexachlorophane intoxication in children

Eighteen children with normal skin were accidentally intoxicated by a talc powder containing 6% hexachlorophane. Four died and two remained paraplegic. The clinical picture was intracranial hypertension, eight patients developing signs of spinal cord damage. The condition seemed to result from massive intramyelinic oedema. In the spinal cord vascular disturbances may occur as mechanical complications of oedema, giving rise to permanent sequelae.

Clinical pharmacology of hexachlorophene in newborn infants

Bathing with soap containing hexachlorophene was instituted during two major staphylococcal epidemics in a Neonatal Intensive Care Unit. Infants who weighed less than 1,200 gm, those with a postconceptional age of less than 35 weeks, and those with large areas of abraded skin were at highest risk to achieve elevated blood HCP concentrations. T 1/2 of HCP ranged from 6.1 to 44.2 hours and appeared to follow first order kinetics. Time of peak blood concentrations of HCP following a bath ranged from 6 to 10 hours. One infant with liver disease achieved a concentration of HCP of 4,350 ng/ml after seven baths and developed clinical symptoms consistent with HCP toxicity.

The distribution of peroxidases in the sciatic nerves of normal and hexachlorophene intoxicated developing rats

Horseradish peroxidase (mol. wt. 40 000) or microperoxidase (mol. wt. 1900) were injected over the sciatic nerve of normal or hexachlorophene (HCP) intoxicated developing rats (3,7,14 and 21 days). Light and electron microscopic studies of nerves after histochemical staining for peroxidase revealed: a) the perineurial barrier to the two peroxidases was established in 21 day normal and HCP intoxicated rats; b) in animals 3-14 days, the perineurial barrier to both peroxidases was not formed and peroxidase staining was observed in the periaxonal space and in the space between paranodal loops of myelin; c) intramyelinic vacuoles, induced by HCP in animals 7-14 days did not show peroxidase staining. HCP-induced intramyelinic vacuolation is due to the separation of the myelin lamellae at the intraperiod line; although these vacuoles are potential extensions of the extracellular space, they are not stained with the extracellular markers horseradish or microperoxidase.

Role of pressure gradients and bulk flow in dynamics of vasogenic brain edema

The authors present the results of an investigation of the vasogenic type of brain edema using cold injury in cats as a model. Their findings indicate that bulk flow and not diffusion should be considered the main mechanism for the spread of edema through the white matter. This conclusion is based on: 1) comparison of the distances actually traveled by various substances during edema spread with those calculated theoretically for migration of the substances by diffusion; 2) coincidence in the speed of movement by two substances (sucrose and albumin) with widely different diffusion coefficients; 3) measurement of interstitial fluid pressure (IFP) at various distances from the lesion showing the presence of increased IFP in the lesion area and decreasing pressures along the edema pathway toward the normal tissue; and 4) the fact that spreading of edema can be significantly impeded by inducing before the cold lesion an intracellular type of brain edema that reduces the size of the extracellular space (ECS) and increases the resistance to flow of edema fluid. The pressure-volume curve of the brain ECS, as derived from determinations of IFP and tissue water content, indicates that initial steep slope in IFP probably represents the high resistance to fluid mobility through the small diameter extracellular channels and the counteracting resistance of the intermingled structures of brain parenchyma to be separated. Once the IFP exceeds these opposing forces, the ECS dilates, fluid mobility increases, and the edema front advances.

Status spongiosus of rat central nervous system induced by actinomycin D

The effect on central myelin of Actinomycin D, an RNA--and, secondarily, a protein-synthesis inhibitor, has been studied by light and electron microscopy. The intracranial injection of this drug produced an extensive status spongiosus of the white matter in the cerebrum, cerebellum, brain stem and optic nerve within 48 h. The status spongiosus was due to vacuole formation within the myelin sheath and to enlargement of the extracellular space. Three types of vacuoles were observed: (a) the most common varieties formed between the inner tongue and the remainder of the myelin sheath; (b) a second variety formed by enlargement of the periaxonal space with separation of the axon from its myelin sheath, and (c) a less common type of vacuolization was due to splitting of the myelin lamellae at the interperiod line to form large intramyelinic vacuoles. Myelinic vacuoles were preceded by nuclear and cytoplasmic changes in oligodendrocytes, which included nucleolar segregation, disaggregation, and diminution in number of ribosomes. These changes were similar to those previously reported in a variety of cells exposed to Actinomycin D. It is suggested that myelin vacuoles result secondarily from the Actinomycin D inhibitory effect on oligodendroglial RNA--and protein-synthesis, rather than from a direct effect of this drug on the myelin sheath.

Central pontine myelinolysis. An ultrastructural and elemental study

Central pontine myelinolysis (CPM) has been classified as a unique disease of myelin with a peculiar localization in the central pons. Although its etiology and pathogenesis are unknown, some have compared its histopathology to that of multiple sclerosis. Ultrastructural studies of suitably preserved tissue have been lacking. We have recently studied 3 cases of CPM, selectively immunostaining 2 cases and examining the fine structure and elemental composition of the third case obtained shortly after death. IgG could not be demonstrated within or around the lesions. The findings of an increased Na/K ratio and of intramyelinic vocuoles at the periphery of the lesion sjggest that the pathogenesis of CPM might include a phase of intramyelinic edema with subsequent rupture of the distended myelin sheaths. An increase in the permeability of the blood-brain barrier might represent a complicating factor. The spheroids in our case are primarily reactive in type and do not support pior light-microscopic interpretations of concomitant neuroaxonal dystrophy. The unexplained presence of tin within the lesion indicates a need for further study of this element in CPM.

Biochemical and pathological studies of myelin in hexachlorophene intoxication

Adult female rats were fed a diet containing 500 ppm hexachlorophene (HCP). Morphological study of brains from these animals showed vacuolation of the myelin sheaths due to separation of myelin lamellae at the minor dense line. However, myelin could be isolated from the brains of these animals in normal yield. The myelin isolated from HCP-fed animals had normal lipid and protein compositions as shown by analyses of the individual lipids and by disc gel electrophoresis of the proteins. Assay of the myelin-specific enzyme, 2',3'-cyclic nucleotide-3'-phosphohydrolase, showed normal specific activity in myelin obtained from HCP-fed rats. Brains of HCP-fed rats showed an increase in wet weight and a decrease in dry weight, with the chloroform-methanol insoluble fraction showing the greatest weight loss. During isolation of myelin from HCP-fed rats material was found floating over 0.32 M sucrose. This "floating fraction" contained a higher ratio of lipid to protein but the same relative proportions of the individual lipids as are found in myelin. The yield of "floating fraction" from each HCP-fed rat was less than 10 percent of the yield of myelin. Disc gel electrophoresis demonstrated the presence of the usual myelin proteins in this fraction, but with a slight increase in the relative amount of the low molecular weight basic protein. The data were compared to reports on the biochemistry of triethyltin poisoning, and it was concluded that vacuolation of myelin in HCP poisoning is probably due to increased permeability of myelin lamellae to water and electrolytes.

Neurotoxicity of hexachlorophene: new pathological and biochemical observations

Twenty female rats with nursing litters were fed a diet containing 500 p.p.m. of hexachlorophene (HCP). The blood concentrations of hexachlorophene in mother rats were 4.7-6.0 mug/ml and in infant rats 2.0-2.5 mug/ml. Fifty percent of mother rats and 75% of infant rats died. Most of the surviving animals were asymptomatic apart from imparied visual function. Ten adult and 20 infant rats were killed by perfusion. Light- and electron-microscopic studies showed vacuolation of myelin in the central and peripheral nervous system and axonal degeneration which was especially severe in the optic nerves. After withdrawal of HCP hydrocephalus ex vacuo was present in the chronically intoxicated infant rats and the optic nerves showed marked atrophy and gliosis. Studies with liver mitochondria prepared from lactating hexachlorophene-fed rats showed a 50-75% inhibition of respiration with succinate as substrate.

Wernicke's encephalopathy: an experimental study in the rhesus monkey

Experimental Wernicke's encephalopathy, induced in rhesus monkeys with a diet lacking thiamine (vitamin B1), is characterized by cavitary necrosis of the striatum as well as a microvacuolar periventricular lesion of the brain stem such as occurs in man. With high resolution light microscopy and electron microscopy, the primary structural alteration in the brain stem lesion, and probably also in the striatum, appears to be that of widespread "blister" formation due to splitting of myelin at the intraperiod line. Microvascular alterations were minimal, even in the most severely affected regions. It is the myelin blisters which give rise to the spongy texture of the neuropil. A similar splitting of myelin has been described in several other experimental encephalopathies, and it is probable that it also occurs in Wernicke's encephalopathy in man.

Hexachlorophene in mice. Effects after long-term percutaneous applications

The toxicity and carcinogenicity of life-time applications of hexachlorophene on the skin of Swiss mice were studied. Twice weekly applications of 0.02 ml of a 50% or 25% solution produced necrosis and ulceration of the skin as well as neurological symptoms and a mortality of up to 22% within two weeks. At autopsy, edema and cystic lesions were seen in the white matter of the central nervous system. The neurological symptoms were reversible, though a proportion of the cystic lesions persisted. Only one skin tumor was seen and the number of tumors of other organs, lymphomas, lung adenomas, liver hemangiomas, and other tumors, was not higher than in the controls. It is concluded from this study that percutaneous application of hexachlorophene has toxic local and systemic effects in mice, but no carcinogenic effects.