Hexachlorophene myelinopathy in premature infants

The sensitivity of the zebrafish embryo coiling assay for the detection of neurotoxicity by compounds with diverse modes of action

In the aim to determine neurotoxicity, new methods are being validated, including tests and test batteries comprising in vitro and in vivo approaches. Alternative test models such as the zebrafish (Danio rerio) embryo have received increasing attention, with minor modifications of the fish embryo toxicity test (FET; OECD TG 236) as a tool to assess behavioral endpoints related to neurotoxicity during early developmental stages. The spontaneous tail movement assay, also known as coiling assay, assesses the development of random movement into complex behavioral patterns and has proven sensitive to acetylcholine esterase inhibitors at sublethal concentrations. The present study explored the sensitivity of the assay to neurotoxicants with other modes of action (MoAs). Here, five compounds with diverse MoAs were tested at sublethal concentrations: acrylamide, carbaryl, hexachlorophene, ibuprofen, and rotenone. While carbaryl, hexachlorophene, and rotenone consistently induced severe behavioral alterations by ~ 30 h post fertilization (hpf), acrylamide and ibuprofen expressed time- and/or concentration-dependent effects. At 37-38 hpf, additional observations revealed behavioral changes during dark phases with a strict concentration-dependency. The study documented the applicability of the coiling assay to MoA-dependent behavioral alterations at sublethal concentrations, underlining its potential as a component of a neurotoxicity test battery.

Evidence-based review of chlorhexidine gluconate and iodine in the preoperative skin preparation of young infants

PURPOSE

The preoperative preparation of young infants' skin requires special considerations. Commonly used solutions for preparing the skin preoperatively include chlorhexidine (CHG) and iodine. The Centers for Disease Control and Prevention (CDC) has recommendations for preparing skin for surgery and other invasive procedures for adults, but they do not have recommendations for young infants' skin. The purpose of this evidence-based literature review is to synthesize the literature, compare, and inform healthcare providers about the safety and efficacy of CHG and iodine as preoperative preparation solutions for young infants' skin. For this project young infants is defined as infants less than 48 weeks' postmenstrual age and those born prematurely and less than 28 days old.

CONCLUSIONS

We analyze 19 articles that met the inclusion criteria. Three discussion themes emerge: systemic absorption, dermatologic burns, and CHG and iodine efficacy.

PRACTICE IMPLICATIONS

We need more research regarding the safety and efficacy of CHG and iodine solutions for preoperative preparation of young infants' skin. Findings suggest the cautious use of CHG and iodine solutions on patients born at or before 28 weeks' postmenstrual age, especially those less than 28 days postnatal age.

Specificity of time- and dose-dependent morphological endpoints in the fish embryo acute toxicity (FET) test for substances with diverse modes of action: the search for a "fingerprint"

The fish embryo acute toxicity (FET) test with the zebrafish (Danio rerio) embryo according to OECD TG 236 was originally developed as an alternative test method for acute fish toxicity testing according to, e.g., OECD TG 203. Given the versatility of the protocol, however, the FET test has found application beyond acute toxicity testing as a common tool in environmental hazard and risk assessment. Whereas the standard OECD guideline is restricted to four core endpoints (coagulation as well as lack of somite formation, heartbeat, and tail detachment) for simple, rapid assessment of acute toxicity, further endpoints can easily be integrated into the FET test protocol. This has led to the hypothesis that an extended FET test might allow for the identification of different classes of toxicants via a "fingerprint" of morphological observations. To test this hypothesis, the present study investigated a set of 18 compounds with highly diverse modes of action with respect to acute and sublethal endpoints. Especially at higher concentrations, most observations proved toxicant-unspecific. With decreasing concentrations, however, observations declined in number, but gained in specificity. Specific observations may at best be made at test concentrations ≤ EC10. The existence of a "fingerprint" based on morphological observations in the FET is, therefore, highly unlikely in the range of acute toxicity, but cannot be excluded for experiments at sublethal concentrations.

Poisoning Through Pediatric Skin: Cases from the Literature

Poisoning through pediatric skin leading to acute systemic symptoms is a relatively uncommonly reported phenomenon. Systemic toxicity through the skin typically occurs by direct contact between therapeutic or non-therapeutic topical agents and the skin. Though uncommon, poisoning through pediatric skin can have significant consequences and must be recognized so the offending agent may be discontinued and appropriate treatment initiated. We performed a literature search for all article types between 1950 and April 2016 to provide a single source of detectable cases of acute toxicity in pediatric patients due to percutaneous exposure. This literature review discusses relevant pediatric skin physiology along with reports of poisoning events that resulted in systemic signs and symptoms and even death to provide a comprehensive report on causes of pediatric poisoning through the skin.

Chemically Induced Myelinopathies

The diverse, structurally unrelated chemicals that cause toxic myelinopathies have been investigated and can be categorized into two types of primary demyelinators. Some demyelinating chemicals seem to leave intact the myeli-nating cells (oligodendrocytes in the central nervous system and Schwann cells in the peripheral nervous system), while others damage the myelinating cells as well as the myelin. The significance between the two is that with the myelinating cells still in tact, repair of the myelin sheath can occur. However, if the myelinating cells are destroyed, repair and reversal of the neuropathy may not occur. Histologically, these chemicals produce an edema of the white matter of the brain, and in some cases the peripheral nervous system, that appears spongy by light microscopy. By electron microscopy, vacuoles can be seen in the myelin surrounding axons. These vacuoles are characterized as fluid-filled separations (splitting) of myelin lamellae at the intraperiod line. In some cases these vacuoles can degenerate further to full demyelination, affecting conduction through those axons. Regeneration of the myelin layers can occur, and in some cases occurs at the same time other axons are undergoing toxic demyelination. Several of these chemicals, however, have been shown to increase cerebrospinal fluid pressure in the brain, optic nerve, and spinal cord, and/or intraneuronal pressure in the perineurium surrounding the axons in the peripheral nervous system. This increased pressure has been correlated with decreased conduction capacity through the axon, ischemia to the neuronal tissue from decreased blood flow because of pressure against the blood vessels, and, if unrelieved, permanent axonal damage. Several of these chemicals havebeen shown to inhibit oxidative phosphorylation, while others uncouple oxidative phosphorylation. One chemical appears to inhibit an enzyme critical to cholesterol synthesis, thus destabilizing myelin. Another hypothesis for a mechanism of action may be in the ability of these compounds to alter membrane permeability.

Diagnostic utility of aquaporin-4 in the analysis of active demyelinating lesions

OBJECTIVE

To assess, in a surgical biopsy cohort of active demyelinating lesions, the diagnostic utility of aquaporin-4 (AQP4) immunohistochemistry in identifying neuromyelitis optica (NMO) or NMO spectrum disorder (NMOSD) and describe pathologic features that should prompt AQP4 immunohistochemical analysis and AQP4-immunoglobulin G (IgG) serologic testing.

METHODS

This was a neuropathologic cohort study of 20 surgical biopsies (19 patients; 11 cord/9 brain), performed because of diagnostic uncertainty, interpreted as active demyelinating disease and containing 2 or more of the following additional features: tissue vacuolation, granulocytic infiltrates, or astrocyte injury.

RESULTS

AQP4 immunoreactivity was lost in 18 biopsies and increased in 2. Immunopathologic features of the AQP4 loss cohort were myelin vacuolation (18), dystrophic astrocytes and granulocytes (17), vascular hyalinization (16), macrophages containing glial fibrillary acid protein (GFAP)-positive debris (14), and Creutzfeldt-Peters cells (0). All 14 cases with available serum tested positive for AQP4-IgG after biopsy. Diagnosis at last follow-up was NMO/NMOSD (15) and longitudinally extensive transverse myelitis (1 each relapsing and single). Immunopathologic features of the AQP4 increased cohort were macrophages containing GFAP-positive debris and granulocytes (2), myelin vacuolation (1), dystrophic astrocytes (1), Creutzfeldt-Peters cells (1), and vascular hyalinization (1). Diagnosis at last follow-up was multiple sclerosis (MS) and both tested AQP4-IgG seronegative after biopsy.

CONCLUSIONS

AQP4 immunohistochemistry with subsequent AQP4-IgG testing has diagnostic utility in identifying cases of NMO/NMOSD. This study highlights the importance of considering NMOSD in the differential diagnosis of tumefactive brain or spinal cord lesions. AQP4-IgG testing may avert biopsy and avoid ineffective therapies if these patients are erroneously treated for MS.

Chlorhexidine use in the neonatal intensive care unit: results from a national survey

Infection prevention guidelines do not endorse chlorhexidine gluconate (CHG) use in neonates who are less than 2 months old. A survey of US neonatology program directors revealed that most neonatal intensive care units use CHG, often with some restrictions. Prospective studies are needed to further address concerns regarding the safety of CHG in patients in the neonatal intensive care unit.

Safety of alcohol hand gel use among children and personnel at a child day care center

BACKGROUND

Alcohol hand gels (AHG) have been used by children in child day care centers (CDCCs) to prevent the transmission of microbes. Because parents and personnel have been concerned about the safety of AHGs, we conducted a trial to assess this.

METHODS

A total of 82 children age 3.5 to 7.2 years (mean, 5.7 years) at 2 CDCCs rubbed their hands with AHG. Alcohol concentrations in expiratory air were measured using an official police alcometer after 15 and 60 minutes. We also conducted a questionnaire survey asking how commonly AHGs were used in CDCCs, obtaining 128 answers from 68 CDCCs (with more than 1 person responding in 6 CDCCs).

RESULTS

All of the alcometer readings were < 0.01 per thousand, although up to 30 contacts with the mucous membranes (mean, 2.4) occurred during the first 15 minutes. An AHG was used in all 68 CDCCs, but only by adults at 11 of them. The most common occasions for using an AHG were before serving food and after cleaning secretions. One case of fire occurred when a worker lit a fire while his hands were covered with AHG. Personnel were most concerned about situations in which children put their fingers into their mouth or eyes after using an AHG.

CONCLUSION

The use of an AHG in CDCCs is safe. Even though children tend to put their hands into their mouth after disinfection, no significant amount of alcohol is absorbed.

Development of an in vitro model for premature neonatal skin: Biophysical characterization using transepidermal water loss

The objective was to develop an in vitro model for the developing skin of the premature neonate. Barriers of different levels of efficiency were produced by differentially tape-stripping the stratum corneum (SC) from the skin of excised porcine ears, and were characterized by measurements of transepidermal water loss (TEWL). In this way, it was possible to express the recorded TEWL as a function of percentage SC thickness (F) generating the following relationship: TEWL = 2.7 + 41.exp [- 0.028.F]. These data were then compared to previously published in vivo measurements of TEWL obtained from a population of premature neonates at various post-conceptional ages (PCA). The latter conformed to a remarkably parallel relationship to that found in vitro with the porcine skin model, namely TEWL = 3.3 + 41.exp [-0.026.(PCA-160)]. It can be suggested, therefore, that the empirically adjusted PCA (i.e., PCA-160) correlates closely with the developing thickness of the neonate's SC. The corollary is that porcine skin, in vitro, tape-stripped to a particular level, can provide a barrier corresponding to a specific degree of neonate maturation and can serve, hence, as a useful tool with which to explore whether transdermal drug delivery in this unique patient population may be beneficial.

Paediatric medicines research in the UK: how to move forward?

There have been numerous studies to show that many of the medicines used in children are used off-label or are unlicensed for use in children. When children are prescribed unlicensed and off-label medications, some people may see them as unknowing participants in informal and uncontrolled experiments. However, the licensing status of a drug can be seen as a by-product of the real issues: the safety, efficacy and quality of these medicines in the current licensing system. It is important to conduct research in order to provide high quality data regarding safety and efficacy to support evidence-based paediatric prescribing. Clinical trials will always be an invaluable means of acquiring vital information about a drug; but when it comes to children, we may find that these trials are not always practical for technical, ethical and financial reasons; therefore, it is important to explore other methodologies in paediatric medicines research. Pharmacoepidemiological and prospective cohort studies could provide vital safety and efficacy data on paediatric medicines; however, resources need to be invested in the methodological research. Paediatric drug formulation research is under-resourced and under-valued, and, unfortunately, fatal and serious adverse reactions due to inappropriate formulations have been reported in many instances. Paediatric medication is a complex problem; we need to use all available tools for research on safety, efficacy and formulation. The reason for lack of progress in paediatric drug research is most likely due to lack of resources and research capacity. The industry and government should work together and invest more money in paediatric drug research. Finally, regulatory authorities, healthcare professionals and academics need to rethink the research strategy in order to provide better medicines for children.

Reflections on errors in neonatology: II. The "Heroic" years, 1950 to 1970

This series errors in neonatology since the 1920s. Three historical periods are defined: the "Hands-Off" years from 1920 to 1950, the "Heroic" years from 1950 to 1970, and the "Experienced" years from 1970 on. In this article, the "Heroic" years, we discuss the Blossom air lock, sulfisoxazole, chloramphenicol, novobiocin, hexachlorophene, Epsom salts enemas, feeding gastrostomy, diaper laundering, and equipment cleaning.

Caring for and protecting the skin of pre-term neonates

Pre-term infants have very immature skin that needs special care and attention and very cautious use of products. More research and guidelines are urgently needed on managing this patient group.

Systemic lupus erythematosus with multiple perivascular spongy changes in the cerebral deep structures, midbrain and cerebellar white matter: a case report

A 42-year-old woman with systemic lupus erythematosus developed an episode of tonic seizures and progressive disturbance of consciousness at the terminal stage. Neuropathological examination of the brain revealed a nearly symmetrical distribution of multiple spongy foci in the internal capsules, thalami, globus pallidus, mesencephalic tegmentum, cerebral peduncles and hilus of the dentate nuclei. The spongy lesions were obviously distributed along apparently intact medium-sized veins, and contained large numbers of macrophages, and axonal spheroids and a few reactive astrocytes, without inflammatory cell infiltration. In addition, the perivenous spongy lesions exhibited IgG immunoreactivity, so it is surmised that some neurotoxic factor(s) that exuded from the veins in the center of the perivenous lesions may have brought about such a unique pathology.

Adverse drug reactions from birth to early childhood

Neonates and older infants are a diverse group of children, quite different from their older counterparts. Adverse drug reactions may have profound immediate, delayed, and long-term implications for their neurologic and somatic development. The intrauterine, neonatal, and infancy periods are the only stages in life in which one is exposed to and affected by drugs administered to another person, the mother. In addition, because of the fragility of the neonate and the complexity of their illnesses, their pharmacotherapy is frequently complicated with misadventure and adverse drug reactions that are unavoidable or difficult to assess. Because of their differences in morphology and disease process and treatments, infants and children experience a different range of adverse drug reactions. These reactions are not necessarily predictable from the adult experience. Despite the advances made in the field of pediatric adverse drug reactions and the lessons learned through the misfortunes involving children, children continue to suffer. Sixty years after the Elixir of Sulfanilamide-Massengill disaster, children continue to be given medications with diethylene glycol in developing countries. Pediatricians, pharmacologists, and others must continue to be vigilant and active in preventing, monitoring, and treating adverse drug reactions in children. Learning from mistakes of the past will improve the health of children by preventing mistakes in the future.

Effect of age and sex on the elicitation of irritant contact dermatitis

Irritant contact dermatitis causes significant disability to numerous consumers and individuals in industry. Knowledge of the prevalence of this disease remains inadequate. Irritant contact dermatitis occurs in workers engaged in occupations where the subjects are exposed to different types and doses of irritants. The intensity of the reaction depends on the quality and the quantity of exposure. Irritant thresholds and dose responses depend on many different factors. This article reviews the clinical and physiological parameters that affect the age and sex related differences in irritant contact dermatitis.

Neurobehavioral impairment and seizures from formaldehyde

Three patients were evaluated for effects of formaldehyde on central nervous system function. Three patients had used formalin, formaldehyde with or without phenol, to fix whole animals for 14-30 y, and a fourth patient was covered several times by formaldehyde and phenol rainout from manufacturing spills. All were disabled, and two had developed seizures. They had elevated mood state scores (82 to 162) and elevated symptom frequency scores (111 to 138), compared with referent subjects. There was excessive fatigue, somnolence, headache, difficulty remembering, irritability, and instability of mood. Compared with referents, choice reaction time was prolonged in four of four (4/4) subjects, blink latency was delayed in 2/2, balance was abnormal in 3/4, and visual fields were constricted in 2/3. Cognitive functions, measured by Culture Fair, block design, and digit symbol tests, were impaired in all. Delayed verbal recall and visual reproduction were impaired in 3/4. Perceptual motor speed on slotted pegboard and trail making A and B tests was reduced in 4/4. Errors on fingertip number writing were abnormal in all. Long-term memory was decreased in only one. Extensive use of formaldehyde at work or repeated airborne exposure to formaldehyde and phenol appears to have impaired central nervous system function.

Transdermal delivery of theophylline to premature infants using a hydrogel disc system

1. Preterm infants show incompletely developed skin with reduced barrier function. The possibility of transdermal delivery of theophylline from hydrogel discs swollen with choline theophyllinate has been investigated. 2. Drug loaded hydrogel discs 2 cm2 in area were applied to the abdomen and occluded. Serum theophylline concentrations were measured in twenty-one infants of less than 31 weeks gestation. 3. Therapeutic concentrations were achieved in 18 individuals, and maintained for up to 15 days after repeated application of discs. A correlation between maximum serum drug concentration and transepidermal water loss, gestation and birthweight was demonstrated.

Percutaneous carbon dioxide excretion in the newborn infant

Percutaneous carbon dioxide excretion was studied in 42 newborn infants between 25 and 39 weeks gestation, using a closed skin cell attached to the abdomen. The rate of excretion during the first few days of life was inversely related to gestation, increasing from a mean of 31 ml/m2/h at term to 198 ml/m2/h below 30 weeks gestation. Postnatally there was a rapid fall in the rate of excretion in very preterm infants to values about twice those found at term. The rate of excretion was linearly related to the CO2 diffusion gradient, and zero diffusion would be expected when there was no diffusion gradient. It is estimated that up to 15% of resting CO2 excretion occurs through the skin of very preterm infants, and more if the tissue PCO2 is elevated.

Current use of skin and wound cleansers and antiseptics

Out of the tumult of a turbulent, eight-century-long background of surgical skin and wound cleansing methods has come a set of basic principles that serve as performance specifications for new developments. Alcohol remains the superior skin antiseptic. Its characteristic rapid-drying effect and consequent loss of bactericidal action can be overcome by maintaining wetness or by admixture with emollients or longer-acting antiseptics. Today's combinations of cleaners, alcohol, and either iodophores or chlorhexidine have emerged from previous eras characterized by the use of metallic compounds, halogen compounds, and tincture of iodine. Published guidelines are important but must be looked upon as current consensus rather than standard practice.

Sterile technique and the prevention of wound infection in office surgery--Part II

Surgical infection and associated complications are minimized by a combination of appropriate sterile technique and careful surgical technique. This review covers the essential elements of infection control for the office-based surgical practice. Recommendations are made concerning operating room facilities, instrument sterilization, and tray set-up (Part I, J Dermatol Surg Oncol 14:1364-1371, 1988). Part II addresses surgical prepping, surgical technique, and prophylactic antibiotics.

Guideline for use of topical antimicrobial agents

This Guideline is based on published data available at the time of writing. The ideal means for comparing performance of various antimicrobial agents is through the conduct of carefully designed, large-scale clinical trials. Recommendations contained in this Guideline are subject to modification as additional data become available. It particularly should be noted that the implementation of universal precautions or body substance isolation has resulted in marked increase in the use of gloves for direct patient contact. Whether there is an additional cost-benefit rationale for handwashing with an antimicrobial agent remains to be studied.

Cuprizone neurotoxicity in the rat: morphologic observations

Weanling male Wistar rats fed a diet containing 0.5-2% cuprizone developed intramyelinic edema of the cerebellar white matter, hilum of the dentate nucleus and superior cerebellar peduncle. Oligodendrocytes in these regions showed hyperchromatic nuclei and abnormally dense cytoplasm, with an increase in the number of free ribosomes and enlargement of mitochondria. Unlike the lesions produced by cuprizone in weanling mice, those in the rat did not lead to demyelination. Cuprizone caused a distal peripheral axonopathy, with degeneration of myelinated axons in the sciatic nerve but preservation of the spinal nerve roots, dorsal root ganglia, posterior spinal funiculi and anterior horn cells. Unmyelinated fibers were largely spared. Some axonal regeneration occurred despite the continued administration of cuprizone. The intramyelinic edema and the nuclear and cytoplasmic abnormalities of the oligodendrocytes disappeared after the resumption of a normal diet.

Percutaneous absorption in preterm infants

The skin of preterm infants varies considerably in its level of maturity. To understand skin absorption in premature infants better, we report a technique for the assessment of percutaneous absorption at various gestational and postnatal ages using stable, isotope-labeled (13C6) benzoic acid. Our results indicate that in the preterm infant, this method detects enhanced skin absorption in the first postnatal days, which declines over three weeks to that expected of a full-term infant. This approach also indicates an inverse relationship between gestational age and skin absorption, as well as postnatal age and skin absorption. The reported technique is a safe and noninvasive method using a model skin penetrant for the study of percutaneous absorption in preterm infants from which basic data may be derived to add to our understanding of skin barrier function.

Skin permeability in the newborn

Skin permeability to drugs was assessed in the newborn infant using an in vitro method. Excised skin samples were studied in a Franz-type cell, and permeability to 0.1 M sodium salicylate was measured. Fourteen samples were studied, from infants of 25-41 weeks gestation and up to 8 days old. Gestation markedly affected skin permeability to salicylate, absorption being 10(2)-10(3) times greater in infants of 30 weeks gestation or less than in term infants. There are important implications for the high permeability of the preterm infant's skin; accidental poisoning from absorption of topically applied agents can easily occur, and the percutaneous route offers an alternative method of therapeutic drug administration.

Percutaneous administration of theophylline in the preterm infant

The preterm infant's skin is a poor barrier to the absorption of chemical agents. The possibility of turning this to the infant's advantage was explored by using the percutaneous route to administer theophylline. A standard dose of theophylline gel, equivalent to 17 mg anhydrous theophylline, was applied to an area of skin 2 cm in diameter over the upper abdomen under an occlusive dressing, and serial theophylline levels were measured; 25 studies were performed in 20 infants of less than or equal to 30 weeks gestation. Therapeutic theophylline levels (greater than 4 mg/L) were achieved in 11 of 13 infants who had not previously received the drug, and were maintained for up to 72 hours. In 12 studies in infants who were previously receiving aminophylline intravenously, theophylline levels were maintained for up to 70 hours. There was a significant decline in the amount of theophylline absorbed in the first 24 hours after application as the infant's postnatal age increased, but satisfactory blood levels were achieved in infants up to 20 days of age. The percutaneous route is a feasible method of administering theophylline in preterm infants.

Ethylene oxide polyneuropathy: clinical follow-up study with morphometric and electron microscopic findings in a sural nerve biopsy

A case is reported of ethylene oxide polyneuropathy after 5 months of exposure. There was symmetrical distal weakness of both lower extremities and transitory reduced nerve conduction velocities with increased latencies. Sural nerve biopsy revealed nerve fibre degeneration of the Wallerian type, associated with reduction of axonal cross-sectional areas and some degree of nerve fibre regeneration that could be confirmed morphometrically. In addition, there was conspicuous paranodal vesicular disintegration of individual myelin lamellae. Unusual cisternae with introverted hemidesmosomes were noted in endoneurial fibroblasts.

Volume regulation and metabolism of suspended C6 glioma cells: an in vitro model to study cytotoxic brain edema

The in vitro model presented provides an approach to study the nature of cell volume control as well as of swelling mechanisms under pathophysiological conditions. Pertinent parameters of cell volume control can be analyzed in isolation due to a virtually infinite extracellular environment precluding secondary effects of the suspended cells. Exposure of C6 glial cells to hypotonic medium was investigated as a model to study fundamental aspects of cell volume control. In confirmation of studies on other cell types glial cells suspended in hypotonic medium recover cell volume after transient swelling. Normalization of cell volume is associated with stimulation of respiration. Moreover, normalization of cell volume in hypotonic medium can be pharmacologically influenced. Addition of naftidrofuryl which enhances cellular O2-consumption led to acceleration of cell volume recovery. On the other hand, inhibition of Na+-K+-ATPase by ouabain did not prevent regulatory volume decrease ruling out a major role of the Na+-transport enzyme in this process. Contrary to hypotonic suspension, hypertonic exposure did not result in volume regulation during an observation period of 3 h. However, this may not necessarily exclude a capability of cell volume to normalize in hypertonic conditions as observed in vivo. Volume control of glial cells in abnormal osmotic medium may--on a cellular basis--reflect fundamental adaptive processes of central nervous tissue. Knowledge of the physiological and biochemical basis of cell volume control is not only of scientific interest but also of therapeutical significance in patients suffering from cytotoxic brain edema.

Surgical antiseptics

The skin cannot be sterilized because approximately 20% of the resident flora are beyond the reach of surgical scrubs and antiseptics. The goal of surgical preparation of the skin with antiseptics is to remove transient and pathogenic microorganisms on the skin surface and to reduce the resident flora to a low level. Four antiseptics which have been popular over the past two decades are discussed. Benzalkonium chloride is somewhat unstable on the skin and is too prone to contamination to be in general use. Hexachlorophene is not recommended due to narrow spectrum and risks secondary to percutaneous absorption. The iodophors are excellent antiseptics, but recent studies raise questions about effectiveness and contamination. Chlorhexidine is a very safe and effective antiseptic. Comparison studies with chlorhexidine, hexachlorophene, and iodophors show chlorhexidine to be the most effective agent. Chlorhexidine can be toxic to the middle ear and irritating to the eyes with direct contact. Caution should be used in these areas with chlorhexidine and other antiseptics.

Placental transfer of hexachlorophene (HCP) in the marmoset monkey (Callithrix jacchus)

Autoradiography was used to study the distribution of 2,2'-14C-methylene-bis-(3,4,6-trichlorophenol) (HCP) in pregnant marmoset monkeys in early (day 30-50) and late (around day 120) gestation and in a newborn (11 days old) pup. Radioactivity was present in the conceptus at all stages of gestation, although the foetal concentration was lower than the maternal. In the embryo an accumulation was observed in the neural tube and in the embryonic membranes. In the late foetus and newborn monkey the highest concentration of radioactivity was found in the liver and the intestinal contents. The brain of the adult and newborn animals showed low concentration. A partial blood-brain barrier was present in the late foetus but, in relation to other tissues, the foetal brain concentration was higher than that of the mother.

Barrier properties of the newborn infant's skin

The barrier properties of the skin were examined in 223 studies in 70 newborn infants of 25 to 41 weeks' gestation, aged from 1 hour to 26 days. Percutaneous drug absorption was studied by observing the blanching response to solutions of 1% and 10% phenylephrine applied to a small area of abdominal skin. Skin water loss was measured at the same site using an evaporimeter. Infants of 37 weeks' gestation or more showed little or no drug absorption and had low skin water losses, indicating that their skin is an effective barrier. By contrast, infants of 32 weeks' gestation or less showed marked drug absorption and high skin water losses in the early neonatal period, indicating that their skin is defective as a barrier. Both drug absorption and water loss in these infants fell steadily; by about 2 weeks of age the skin of the most immature infants functioned like that of mature infants. The varying barrier properties can be explained by the poor development of the stratum corneum in the more premature infants at birth and its rapid maturation after birth. The trauma caused to the skin by use of adhesive tape and the fixation of transcutaneous oxygen electrodes resulted in increased drug absorption and water loss from the damaged area.

Percutaneous alcohol absorption and skin necrosis in a preterm infant

A 27-week gestation infant developed severe haemorrhagic skin necrosis on the back and buttocks after umbilical arterial catheterisation. Before catheterisation the skin was cleaned with methylated spirits. A blood alcohol level taken 18 hours after catheterisation showed a blood ethanol level of 259 mg/100 ml and a blood methanol level of 26 mg/100 ml. We conclude that the methylated spirits caused this extensive skin damage and that percutaneous absorption via the readily permeable skin of this immature baby resulted in the dangerously high alcohol levels.

Iatrogenic disease in the newborn

The role of intrapartum asphyxia and cerebral birth trauma as an important cause of perinatal mortality is well known and its contribution to perinatal morbidity as a cause of cerebral palsy is widely appreciated. This has led to more careful monitoring of pregnancy and labour, although monitoring techniques are not without hazard. The widespread availability of intensive care facilities for the newborn has resulted in the survival of many infants, particularly those of low birth weight, who might previously have died. Efficacious modes of treatment may, unfortunately, bring in their wake serious problems in the form of iatrogenic disease which may cause or contribute to rapid demise or whose effects may be fully apparent for many years. Ante natal investigations have also become frequently used and have their own hazards.

Hexachlorophene retinopathy in suckling rats. A light- and electron-microscopic study of short-term and long-term effect of hexachlorophene intoxication on the retina of young rats

Hexachlorophene (HCP) in very large doses has a toxic effect on the retina of adult rats. The present study examined the sensitivity of the developing retina to smaller doses and its ability to recover from neurotoxic damage. Suckling rats were intoxicated with HCP added to the mothers' diet. The retinae of the pups were examined by light and electron microscopy for early and late effects. All dose levels above 100 ppm caused vacuolar degeneration of the outer segments of photoreceptor cells within 14 days of intoxication, followed by degeneration of the inner segments after 28 days. The cell bodies of photoreceptor cells and all other retinal layers remained normal. Suckling intoxicated with HCP (100 - 500 ppm) added to the mothers' diet for 28 days and then withdrawn, showed no recovery of the outer or inner segments o photoreceptors when examined up to 150 days later. In addition, extensive degeneration and loss of photoreceptor cell occurred after withdrawal of HCP and the degenerative process extended to involve the inner nuclear layer. The rate of appearance of pathological changes was proportional to the total amount of ingested HCP. This study showed that photoreceptor cells in newborn rats are highly sensitive to HCP. The retinal lesions were irreversibly an continued to progress by continued trans-synaptic degeneration after withdrawal of the toxic agents.

Hexachlorophene and the central nervous system. Toxic effects in mice and baboons

A study on hexachlorophene encephalopathy in mice and baboons is reported. By light microscopy, a severe spongiform lesion of the central nervous system (CNS) was localized in the white matter, without myelin breakdown or cellular reaction. By electron microscopy, the myelin alteration was characterized by wide intralamellar spaces or "splitting" developed in the intraperiod line of compact sheaths. The acute changes described were induced by administration of the drug by the digestive or cutaneous routes at various dosage levels in an aqueous solution or in talcum powder. The toxic effects depended on the age of the animals, the survival times and the concentrations of hexachlorophene, i.e., 6%, 3%, and 0.5%. The findings are compared with previous reports on the neurotoxicity of hexachlorophene and other chemicals in human and experimental animals. Hexachlorophene cannot be recommended for use in young infants because of its neurotoxicity in very low doses as demonstrated in the present report.

Neonatal spongioform myelinopathy after restricted application of hexachlorophane skin disinfectant

At least four out of 97 low birth weight (less than 1750 g) newborn infants who had received only limited skin disinfection with 3% hexachlorophane (HCP) emulsion developed spongioform myelinopathy in association with detectable amounts of HCP in their brains. These four cases were found in a post-mortem survey of 20 out of the 27 infants who died. Another nine of these infants had detectable amounts of HCP in the brain but no myelinopathy. It is at present not possible to define a 'safe" level of exposure to 3% HCP emulsion for small preterm infants in the first 2 weeks of life.