Abnormalities of the visual system in infants exposed to cocaine

Optic atrophy in prematurity: pathophysiology and clinical features

Optic atrophy is an important cause of visual impairment in children, and the aetiological profile has changed over time. Technological advancements led by neuroimaging of the visual pathway and imaging of the optic nerve with optical coherence tomography have accelerated the understanding of this condition. In the new millennium, an increasing prevalence of prematurity as a cause of optic atrophy in children has been highlighted. This new shift has been linked with increasing rates of premature births and improved neonatal survival of preterm infants. The available literature is limited to hospital and registry-based cohorts with modest sample sizes, methodological heterogeneity and selection bias limitations. Larger studies that are better designed are required to better understand the contribution of prematurity to the disease burden. In addition to considering other life-threatening aetiologies, screening for premature birth should be covered as part of a comprehensive history when evaluating a child with paediatric optic atrophy.

Exposure to Morphine and Cocaine Modify the Transcriptomic Landscape in Zebrafish Embryos

Morphine and other opioid analgesics are the drugs of election to treat moderate-to-severe pain, and they elicit their actions by binding to the opioid receptors. Cocaine is a potent inhibitor of dopamine, serotonin, and noradrenaline reuptake, as it blocks DAT, the dopamine transporter, causing an increase in the local concentration of these neurotransmitters in the synaptic cleft. The molecular effects of these drugs have been studied in specific brain areas or nuclei, but the systemic effects in the whole organism have not been comprehensively analyzed. This study aims to analyze the transcriptomic changes elicited by morphine (10 uM) and cocaine (15 uM) in zebrafish embryos. An RNAseq assay was performed with tissues extracts from zebrafish embryos treated from 5 hpf (hours post fertilization) to 72 hpf, and the most representative deregulated genes were experimentally validated by qPCR. We have found changes in the expression of genes related to lipid metabolism, chemokine receptor ligands, visual system, hemoglobins, and metabolic detoxification pathways. Besides, morphine and cocaine modified the global DNA methylation pattern in zebrafish embryos, which would explain the changes in gene expression elicited by these two drugs of abuse.

Impact of Prenatal Exposure to Opioids, Cocaine, and Cannabis on Eye Disorders in Children

OBJECTIVES

Prenatal substance exposure is associated with abnormal visual evoked potentials in offspring, but whether ocular abnormalities are present past infancy is unclear. We determined the association between prenatal substance exposure and hospitalizations for eye disorders in childhood.

METHODS

We conducted a longitudinal cohort study of 794,099 infants born between 2006 and 2016 in all hospital centers in Quebec, Canada. We identified infants prenatally exposed to opioids, cocaine, cannabis, and other illicit substances and followed them over time to assess eye disorders that required in-hospital treatment, including retinal detachment and breaks, strabismus, and other ocular pathologies. We calculated incidence rates and hazard ratios (HR) with 95% confidence intervals (CI) for the association of prenatal substance exposure with risk of eye disorders, adjusted for patient characteristics.

RESULTS

Infants exposed to substances prenatally had a higher incidence of hospitalizations for eye disorders compared with unexposed infants (47.0 vs 32.0 per 10,000 person-years). Prenatal substance exposure was associated with 1.23 times the risk of hospital admission for any eye disorder during childhood compared with no exposure (95% CI 1.04-1.45). Risks were greatest for strabismus (HR 1.55, 95% CI 1.16-2.07) and binocular movement disorders (HR 1.96, 95% CI 1.00-3.83). Opioid use was strongly associated with the risk of ocular muscle disorders (HR 3.15, 95% CI 1.98-5.01).

CONCLUSIONS

Prenatal substance exposure is significantly associated with future hospitalizations for eye disorders in childhood. Efforts to minimize substance use in women of reproductive age are needed in light of the current opioid epidemic.

Effects of prenatal exposure to alcohol, tobacco and other drugs of abuse on retinal development

PURPOSE

To assess structural changes in the retina using optical coherence tomography (OCT) in children prenatally exposed to toxic substances.

METHODS

The study included a total of 49 infants, aged between 5 and 18years, exposed to toxic substances during pregnancy. Among the exposed children, 25 were exposed to tobacco, 20 were exposed to alcohol, and 4 children were exposed to other drugs of abuse. All children underwent a complete ophthalmology examination, including an OCT. The results were compared against a control group composed of 25 infants, age matched with controlled pregnancy, and not exposed to toxic substances.

RESULTS

Children prenatally exposed to toxic substances showed significantly thinner average retinal nerve fibre layer (RNFL) compared with control children (81.5 vs. 99.7μm; P<.005), as well as RNFL thinning in its four quadrants (superior RNFL: 97.5 vs. 127.5μm; P<.005; nasal RNFL: 61.5 vs. 72.3μm; P<.005; inferior RNFL: 99.8 vs. 128.6μm; P<.005, temporal RNFL: 58.3 vs. 68.2μm; P<.005). Exposed children also exhibited a thinner ganglion cell layer (72.9 vs. 85.9; P<.005). Greater RNFL thinning was observed in children exposed to drugs of abuse (RNFL thinner average=72), followed by children exposed to alcohol (RNFL thinner average=72.9), and finally the least affected were those children exposed to tobacco during pregnancy (RNFL=94.6).

CONCLUSION

Toxic substances during pregnancy interfere in retinal development. These results strengthen the evidence about the avoidance of any toxic substance during pregnancy.

Chronic cocaine effects in retinal metabolism and electrophysiology: treatment with topiramate

PURPOSE

Cocaine abuse is a major public health problem with multiple-related complications. Indeed, cocaine can affect almost every organ of the human body, but little is known about its effects on the visual system. The main purpose of this work was to study if topiramate was able to reverse changes in retinal metabolism and retinal function induced by chronic cocaine exposure in adult rats.

MATERIALS AND METHODS

Sixteen Wistar rats were treated with a daily oral dose of cocaine during 36 days. Sixteen rats receiving NaCl 0.9% served as controls. Eight control and eight cocaine animals were administered topiramate from day 18 to day 36 of the experiment. Malondialdehyde (MDA), glutathione (GSH) and glutamate content, as well as glutathione peroxidase (GPx) activity in retina tissue homogenates were determined. Retinal function was assessed by electroretinogram (ERG).

RESULTS

Glutamate concentration was increased in the retinas of cocaine-treated rats. No changes in oxidative stress parameters were observed in the retinas of cocaine-treated rats when compared with the control ones. Cocaine induced a decrease in the a-wave and b-wave ERG amplitude. The administration of topiramate reversed cocaine-induced increase in glutamate concentration and had little effect on a-wave and b-wave ERG amplitude. Topiramate, a drug used during the last decade for the treatment of epileptic seizures, is able to reverse the cocaine-induced alterations observed in retinal glutamate concentration.

CONCLUSIONS

We can conclude that retinal glutamate metabolism and function may be affected by exposure to cocaine. We confirm that topiramate, a treatment recently proposed for cocaine dependence, is also able to recover partially cocaine-induced changes in the retina.

Nystagmus and reduced visual acuity secondary to drug exposure in utero: long-term follow-up

PURPOSE

To investigate nystagmus and other visual system abnormalities among children exposed to opiates and benzodiazepines in utero.

METHODS

Retrospective case series comprising clinical examination and case note review of 25 children with nystagmus and reduced vision who were exposed to controlled drugs during pregnancy.

RESULTS

Twenty-four children were exposed to opiates, of whom 13 were also exposed to diazepam. One child was exposed to diazepam alone. All children had horizontal nystagmus, which was either fine pendular or jerk type. The nystagmus had a latent element in 4 children and 8 adopted a compensatory head posture. Where the time of onset of nystagmus was known, it was always prior to 6 months of age. At least 9 children (36%) had delayed visual maturation. The mean initial logarithm of the minimum angle of resolution binocular best-corrected visual acuity (BCVA) was 0.54 at an average of 22 months of age. Thirteen children were followed up for 6 months or longer and their BCVA improved to 0.4 at an average age of 48 months. The nystagmus was clinically improved in only 5 patients. Electroretinogram testing was normal in the 4 children tested. The only ocular structural abnormality was binocular optic nerve hypoplasia in 2 children.

CONCLUSION

Exposure to opiates and benzodiazepines in utero may be associated with permanent nystagmus and reduced visual acuity. This is most likely the result of insult(s) to the central nervous system rather than the eyes.

Correlation of axon size and myelin occupancy in rats prenatally exposed to methamphetamine

The abuse of methamphetamine (MA) and other psychostimulants is a social and medical problem. In particular, the use of these drugs by pregnant women results in an increased number of children exposed prenatally to psychostimulants. Our previous work has demonstrated that prenatal exposure to MA affects the normal development of the rat visual system due to alterations of biochemical mechanisms and oxidative stress. It was also demonstrated that prenatal exposure to MA affects the dopaminergic system of the rat retina and optic nerve (ON) myelination. The present work was conducted to evaluate the effects of prenatal exposure to MA on the development of the ON in terms of axon growth and the myelin sheath. Pregnant female rats were given 5 mg/kg/day MA, subcutaneously (s.c.), in 0.9% saline from gestational day (GD) 8 to 22. The pair-fed control group was injected s.c. with an isovolumetric dose of 0.9% saline. Qualitative analysis was performed using representative electron ultramicrographs. Quantitative analysis was performed at an electron microscopic level on ON cross sections; parameters measured included myelinated/unmyelinated ratio, outer axon mean area, inner axon mean area, myelin mean area, myelin occupancy and distribution of axons by size. The ON of prenatally MA-exposed rats presented a higher rate of deformed axons and slighter lamellar separation. At PND 21, the average outer axon area of MA-treated males was significantly reduced. The average inner axon area only showed a significant difference between MA and control males for axons with an area of less than 0.3 microm(2). The average myelin area of MA-treated males was significantly reduced, and in MA-treated females was only significantly reduced in axons with an area of less than 0.3 microm(2). The percentage of myelin occupancy was significantly affected in MA-treated males, and in MA-treated females in the group of axons with an area of more than 0.3 microm(2). At PND 14 no significant differences were found between MA and control groups. The spectrum of ON myelinated axon size of MA-treated animals was shifted to the left at PND 14 and PND 21 for both genders. These results are in agreement with previous animal studies of prenatal and perinatal exposure to drugs of abuse. Taken together, these data indicate that the ON is vulnerable to early exposure to MA which causes developmental changes and may interfere with the functioning of the visual system.

Myelination changes in the rat optic nerve after prenatal exposure to methamphetamine

The use of psychostimulants during adolescence and early adult life has increased in recent years. It is known that these substances affect the sensory systems, and the optic nerve has been shown to be a target tissue. This work was conducted to evaluate the effects of prenatal exposure to methamphetamine (MA) on the developmental pattern of the rat optic nerve. Pregnant female rats were given 5 mg/kg body weight/day MA, s.c., in 0.9% saline from gestational days 8 to 22. The control group was injected with an isovolumetric dose of 0.9% saline. Animal model parameters, such as gestational body weight evolution, food intake and pups parameters were registered. The offspring were sacrificed at postnatal days (PND) 7, 14 and 21. Morphometric analyses were performed at light and electron microscopic levels on optic nerve cross sections; parameters measured included optic nerve diameter and area, axonal density, total number of axons and myelin thickness. Myelin basic protein (MBP) was measured by western blotting in optic nerve samples at PND14 and PND21. The animal model parameters, such as maternal and pup weight, showed no significant differences between MA and control groups. Optic nerve diameter was smaller at PND7 in the male MA group and in both male and female MA groups at PND21. The mean cross-sectional area was smaller at PND14 in the male MA group and in both male and female groups at PND21. The total number of myelinated axons did not vary between groups at any of the studied ages. The myelin thickness of the axons in MA-treated females was thinner when compared with the respective control group at PND21. No other differences were found concerning myelin thickness. There was a reduction of MBP protein expression in MA-injected females at PND14 and PND21. The combined results suggest that prenatal exposure to MA affects the myelination process.

Methamphetamine and lipid peroxidation in the rat retina

BACKGROUND

The use of psychoactive drugs during adolescence and early adult life has increased in the last few decades. It is known that developmental exposure to psychostimulants affects the sensory systems, and the retina has been shown to be a target tissue. This work was conducted to evaluate the pattern of lipid peroxidation in the rat retina following prenatal exposure to methamphetamine (MA).

METHODS

Pregnant female Wistar rats were given MA (5 mg/kg of body weight/day; SC, in 0.9% saline) from GD 8 to 22. Offspring were sacrificed at postnatal days (PNDs) 7, 14, and 21. The retinas were homogenized, and both the total antioxidant and superoxide dismutase (SOD) activities were measured by enzymatic-colorimetric methods. The lipid peroxidation byproducts (malondialdehyde [MDA] and MDA-like metabolites) were measured by the thiobarbituric acid test.

RESULTS

Total antioxidant levels were lower in the MA group at PND 21 in both males and females. The activity of SOD was higher in PND 7 females from the MA group. MDA levels were higher in the MA group at PND 21 in both genders.

CONCLUSIONS

These findings suggest that prenatal-induced MA toxicity in the retina may be related to lipid peroxidation processes and oxidative stress.

Optic nerve axons: life and death before birth

In the 2004 Bowman Lecture, I give a panegyric for Sir William Bowman, an estimate of the importance and the epidemiology of anterior visual pathway developmental disorders, followed by a history of the anterior visual system. I review the normal development of the optic nerve and chiasm and the main developmental disorders: Optic Nerve Aplasia, Optic Nerve Hypoplasia and Achiasmia.

Fetal Alcohol and Drug Effects

BACKGROUND

Alcohol and drug use by pregnant women are harmful to the developing embryo and fetus. Teasing apart the specific contributions of each substance to adverse child outcome, however, proves difficult in practice. The risks to the neonate include intra-uterine growth retardation, birth defects, altered neurobehavior, and withdrawal symptoms. Subsequent behavior, development, and neurologic function may also be impaired.

REVIEW SUMMARY

Maternal cigarette smoking carries the greatest risk of impaired fetal growth of any of the substances discussed herein and has been linked to subsequent externalizing behaviors. Alcohol is a well-established teratogen. Heavy exposure to alcohol in a subset of infants is associated with fetal alcohol syndrome (FAS). Mental retardation is one of the main sequelae of alcohol exposure in utero. Fetal marijuana exposure has no consistent effect on outcome. Prenatal cocaine exposure has not been shown to have any detrimental effect on cognition, except as mediated through cocaine effects on head size. Although fetal cocaine exposure has been linked to numerous abnormalities in arousal, attention, and neurologic and neurophysiological function, most such effects appear to be self-limited and restricted to early infancy and childhood. Opiate exposure elicits a well-described withdrawal syndrome affecting central nervous, autonomic, and gastrointestinal systems, which is most severe among methadone-exposed infants.

CONCLUSION

Most adverse effects of prenatal drug exposure are self-limited, with catch-up growth and resolution of withdrawal and of prior neurobehavioral abnormalities noted over time. The exception is alcohol, which is linked to life-long impairments (i.e., mental retardation and microcephaly) and possibly cigarette-related behavioral effects. The absence of tangible evidence of detrimental long-term cocaine effects may reflect limitations in the methodology used to identify children at greatest risk for adverse outcome.

Visually impaired children with posterior ocular malformations: pre- and neonatal data and visual functions

AIM

To analyse pre- and neonatal data and ocular findings in children with visual impairment caused by posterior ocular malformations.

METHODS

Medical records were scrutinized, dried blood spot cards were analysed for virus DNA and ophthalmological assessments were performed in 28 children with optic nerve hypoplasia (ONH) and 10 with optic/chorio-retinal coloboma.

RESULTS

Prenatal exposure to possible teratogens was documented in 5/28, herpes simplex virus type 1 DNA was identified in the dried blood spot cards of 1/26 children and neonatal hypoglycaemia in 12/28 children with ONH. The time delay from ocular to endocrinological diagnosis and treatment was 3 years. Children with ONH and severe visual impairment had endocrinopathy more often (11/13) than ONH children with better visual functions (5/15). Prenatal exposure to teratogens or neonatal hypoglycaemia was not identified in any of the children with coloboma.

CONCLUSION

Neonatal hypoglycaemia was common in children with ONH. Severe visual impairment predicted endocrinopathy. Analysis of dried blood spot cards could serve as an additional diagnostic tool in children with ocular malformations.

Optic nerve hypoplasia: Risk factors and epidemiology

OBJECTIVES

To study the epidemiology of optic nerve hypoplasia.

DESIGN AND METHODS

Children with optic nerve hypoplasia and visual impairment were identified through the Swedish Register of Visually Impaired Children. Pre- and perinatal characteristics were obtained from the Medical Birth Registry and by scrutinizing pregnancy and delivery records. Clinical characteristics of children with optic nerve hypoplasia are described. The following risk factors were studied: maternal age, parity, maternal smoking, gestational duration, birth weight, delivery method, Apgar score, maternal disease during pregnancy, drugs used in early pregnancy.

RESULTS

Young maternal age, first parity, maternal smoking, preterm birth and factors associated with preterm birth were risk factors for optic nerve hypoplasia. There was an indicated association with the use of fertility drugs and antidepressant drugs.

CONCLUSIONS

Optic nerve hypoplasia is apparently associated not only with other anomolies, notably of the central nervous system, but also with signs of general disturbance in fetal development.

Fetal effects of cocaine: an updated meta-analysis

BACKGROUND

A very large number of women in the reproductive age group consume cocaine, leading to grave concerns regarding the long term health of millions of children after in utero exposure. The results of controlled studies have been contradictory, leading to confusion, and, possible, misinformation and misperception of teratogenic risk.

OBJECTIVE

To systematically review available data on pregnancy outcome when the mother consumed cocaine.

METHODS

A meta-analysis of all epidemiologic studies based on a priori criteria was conducted. Comparisons of adverse events in subgroups of exposed vs. unexposed children were performed. Analyses were based on several exposure groups: mainly cocaine, cocaine plus polydrug, polydrug but no cocaine, and drug free.

RESULTS

Thirty three studies met our inclusion criteria. For all end points of interest (rates of major malformations, low birth weight, prematurity, placental abruption, premature rupture of membrane [PROM], and mean birth weight, length and head circumference), cocaine-exposed infants had higher risks than children of women not exposed to any drug. However, most of these adverse effects were nullified when cocaine exposed children were compared to children exposed to polydrug but no cocaine. Only the risk of placental abruption and premature rupture of membranes were statistically associated with cocaine use itself.

CONCLUSIONS

Many of the perinatal adverse effects commonly attributed to cocaine may be caused by the multiple confounders that can occur in a cocaine using mother. Only the risk for placental abruption and PROM could be statistically related to cocaine. For other adverse effects, additional studies will be needed to ensure adequate statistical power.

The search for congenital malformations in newborns with fetal cocaine exposure

CONTEXT

The association between prenatal cocaine exposure and congenital anomalies is not definitive.

OBJECTIVE

To determine whether prenatal cocaine exposure results in an increased number or identifiable pattern of abnormalities.

DESIGN

A prospective, longitudinal cohort enrolled between 1991 and 1993.

SETTING

Rural public health population delivering at a regional tertiary medical center.

PATIENTS

Two hundred seventy-two offspring of 154 prenatally identified crack/cocaine users and 154 nonusing controls were matched on race, parity, location of prenatal care (that related to level of pregnancy risk), and socioeconomic status. Drug use was determined through repeated in-depth histories and urine screens. Infants not examined within 7 days of birth were excluded.

OUTCOME MEASURES

Assessments were made by experienced examiners masked to maternal drug history. Included were 16 anthropometric measurements and a checklist of 180 physical features defined and agreed upon in advance.

RESULTS

There were no differences on major risk variables between the included and excluded infants. There were significantly more premature infants in the cocaine-exposed group. Cocaine-exposed infants were significantly smaller in birth weight, length, and head circumference but did not differ on remaining anthropometric measurements. There was no difference in type or number of abnormalities identified between the exposed and nonexposed groups. There was no relationship between amount or timing of exposure and any of the outcomes.

CONCLUSIONS

This prospective, large-scale, blinded, systematic evaluation for congenital anomalies in prenatally cocaine-exposed children did not identify an increased number or consistent pattern of abnormalities.

Effects of neonatal exposure to cocaine in the development of the neurotransmitters retinal systems: an immunocytochemical and neurochemical study

The visual system of rodents is affected if exposure to drugs, e.g., cocaine, occurs during prenatal or early postnatal development. This study aims to evaluate, in an experimental model of neonatal exposure to cocaine in the rat, the immunocytochemical expression of tyrosine hydroxylase in the retina and the levels of different neurotransmitters and its metabolites. Male Wistar rats were given 15 mg cocaine hydrochloride/kg body weight/day, subcutaneously, in two daily doses, from the day after birth (PND1) to PND6, 13, and 29. Controls were given 0.9% saline. Groups of rats were perfused at PND7, 14, and 30 with fixative, and the retinas were processed as wholemounts, and immunostained with the antibody anti-TH. Other groups were decapitated, and the retinas were dissected and processed by high performance liquid chromatography with electrochemical detection (HPLC-EC) for determination of dopamine and metabolites (DOPAC and HVA). A reduction in the retinal surface area was detected in the PND30 cocaine group, and a decrease in the density of the small TH-IR cells was found in the PND14 cocaine group although not reaching significant levels. The other quantitative parameters did not differ between the control and cocaine groups. The levels of neurotransmitters did not significantly differ between the groups at any age. These results show a differential vulnerability of the dopaminergic system of rats exposed neonatally to cocaine when compared with the effects found after prenatal exposure to the same drug.

Long-term effects of early cocaine exposure on the light responsiveness of the adult circadian timing system

Early cocaine exposure is associated with a wide variety of neurobehavioral and teratogenic effects. The current study was conducted to determine the long-term effects of such exposure on the hamster circadian timing system. The circadian system drives rhythms in a tremendous diversity of physiological, behavioral, and endocrine functions. The fetal circadian pacemaker has recently been shown to express a functional D1 dopamine system that is involved in maternal-fetal entrainment. Maternally administered cocaine, acting on the fetal clock, could therefore potentially have long-lasting effects on exposed offspring. Pregnant SCN-lesioned hamsters or their pups, maintained in constant dim illumination (DD), were administered cocaine (30 mg/kg, SC, N = 10 litters) or saline vehicle (N = 5 litters) from embryonic (E) day 15 [day of mating = E0] through postnatal (P) day 5. Upon weaning (P21), cocaine- and saline-treated offspring were placed in individual running wheels for a period of 5-6 weeks. Individuals were then challenged with 1-h light pulses at three circadian times (CT7, CT14, CT18). Cocaine-treated litters had a statistically significant mean phase advance of +0.32 h at CT14 compared with the mean phase delay of 2.13 h of the saline-treated litters. No significant differences were seen at the other two circadian times, although there was heterogeneity in the responses among cocaine-treated animals. This represents the first demonstration of an effect of perinatal cocaine on the circadian timing system. Together with the recent demonstration of D1 receptors in the human SCN, these findings raise the possibility that gestational cocaine abuse by humans may also lead to later disturbances in the circadian timing system.

Cocaine in pregnancy. Recent data on maternal and fetal risks

Cocaine continues to be abused during pregnancy, creating increased demands on the health care system. Epidemiology and basic science research have identified and confirmed risks of adverse maternal and fetal effects when cocaine is used during pregnancy. These effects of cocaine in pregnant women often are influenced by a number of confounding variables. This article reviews those cocaine effects as well as recent data, which examine in greater detail the risks of adverse outcomes of prenatal cocaine exposure during pregnancy.

Development of the eye after gestational exposure to cocaine. Vascular disruption in the retina of rats and humans

Clinical and basic research in the area of drugs of abuse are of utmost importance since they provide the necessary background for health programs in one of the main problems of contemporary society. The available data in this field demonstrate that acute, subacute and/or chronic abuse of illicit drugs, e.g., cocaine, alters the neurochemistry and functioning of the neural circuitries. Although recent works demonstrated that the visual system is lesioned after exposure to cocaine during the active periods of development, no studies have provided detailed information on the effects of these substances on the development of this sensory system. The present paper will report: 1) the vulnerability of the developing visual system to gestational exposure to cocaine; 2) the effects of cocaine in the visual system during the more active periods of development in humans and, as far as possible, the establishment of homologies with animal models where exposure is made in corresponding periods of human gestation, and 3) the characterization of the vascular disruption caused by ischemic/hypoxic mechanisms. The clinical study focused the ophthalmologic evaluation of newborns exposed in utero to illicit drugs. Newborns exposed to cocaine in utero showed marked vascular disruption in the retina: superficial and deep hemorrhages that, although morphologically similar to neonatal retinal hemorrhages, presented a longer reabsorption time when compared with the neonatal hemorrhagic lesions due to birth trauma in the general population. Prolonged eyelid edema was also a prominent finding. The animal study was conducted in Wistar rats exposed prenatally (gestational days 8 to 22) and postnatally (postnatal days 1-6, 1-13 and 1-29) to 60 mg/kg body weight/day and 15 mg/kg body weight/day, respectively, to cocaine hydrochloride administered subcutaneously; control groups included pair-feeding during the same experimental periods. Similar alterations to those observed in the newborns where exposure to cocaine was affirmative, were found: intraretinal hemorrhages allied to signs of chronic ischemia both in the outer retina-photoreceptor rosettes and in the inner retina-epiretinal glial membranes. Taking into consideration that the visual system is one of the more important sensory systems, the identification and characterization of these alterations, the similarity between animal and human findings, and their relation with cocaine per se, can provide a sound data base for illicit drug prevention programs.

Pattern shift visual evoked potentials in abstinent cocaine-dependent, alcohol-dependent, and cross-dependent patients

The present study evaluated pattern shift visual evoked potential (VEP) amplitudes and latencies in four groups of adult subjects, characterized by the presence/absence of a recent history of alcohol dependence factorially crossed with the presence/absence of a recent history of cocaine dependence. All of the subjects were healthy and uncomplicated by histories of serious head injury, seizures (including drug-related seizures), and major medical, neurological, or psychiatric disorders. The subjects comprising the three patient groups were evaluated after 1 - 5 months of verified abstinence. Analyses of VEPs evoked by checkerboard reversal indicated a main effect of previous cocaine dependence on P100 latency. No main effect of previous alcohol dependence and no alcohol by cocaine dependence interaction were detected. The increased P100 latencies detected in abstinent, cocaine-dependent subjects are most likely related to cerebrovascular and neurological effects of chronic cocaine use.

Neurologic and ophthalmologic findings in children exposed to cocaine in utero

We studied a cohort of 73 children exposed to cocaine in utero to characterize the spectrum of neurologic and ophthalmologic abnormalities; 36 children with no documented in utero drug exposure were selected as a control group. Most referrals of cocaine-exposed children to the child neurologist were made in the 1st year of life (81%). Reasons for referral were hypertonia (29%), seizures (22%), developmental delay (11%), tremulousness (11%), and hypotonia (4%). The most common abnormal finding in the cocaine-exposed children was hypertonia/hyperreflexia (63%), which was rarely seen in the control group. In addition, hypertonia/hyperreflexia was underdiagnosed by referring physicians. Similarly, hypotonia was seen on neurologic examination of cocaine-exposed children more frequently than documented by referral (16% versus 4%). Hypotonia was rarely seen in the control group. Twelve (43%) of 28 cocaine-exposed children seen by a pediatric ophthalmologist had structural ophthalmologic abnormalities. Neurologic and ophthalmologic findings suggesting structural lesions of the nervous system must be considered in cocaine-exposed children.

Effects of prenatal cocaine exposure in the photoreceptor cells of the rat retina

Despite the increasing evidence of eye abnormalities, the effects of prenatal exposure to cocaine on the visual system are still poorly understood. This study was aimed at analyzing the qualitative and quantitative organization of the retinal photoreceptor cells (PR) and outer nuclear layer (ONL) after prenatal exposure to cocaine in the rat. Pregnant Wistar rats were given sc injections of cocaine hydrochloride (60 mg/kg body wt/d) or saline or were not manipulated; analyses were performed in the 14- and 30-d-old male offspring. Radial semithin and ultrathin sections of epon-embedded flat mounts of the retina showed displaced PR-like cells in the inner nuclear layer (INL), picnotic PR nuclei in INL, and ONL, and retinal PR rosettes and outer-segment debris in the subretinal space. The quantitative study showed an increased density of PR-like nuclei in the INL in PND14 cocaine-treated rats that were within normal values at PND30; no changes were detected in the PR mean nuclear diameter and in the packing density of PR nuclei in the ONL. These data constitute the first morphological demonstration of photoreceptor damage after prenatal cocaine-exposure probably owing to a direct action of the drug and/or to the cocaine-induced ischemia/hypoxia.

Effects of prenatal cocaine exposure in the retinal ganglion cell layer of the rat. A morphometric analysis

To study the effects of prenatal cocaine-exposure on the developing retinal ganglion cell layer of the rat, female Wistar rats were administered subcutaneously (sc) cocaine hydrochloride (60 mg/kg body wt/d) or saline, or were not manipulated from gestational d 8-22. Male offspring were sacrificed at postnatal day 14 and 30. Radial semithin sections of epon-embedded flat mounts of the retinal quadrants were used to evaluate the following parameters along the centroperipheral axis: 1. Thickness of ganglion cells plus nerve fiber layer; 2. Nuclear size of ganglion cell layer neurons; and 3. Linear density (number per unit length) of ganglion cell layer neurons. To study the effects of cocaine and age on the retinal areas (temporal/nasal, dorsal/ventral), a repeated measures analysis of variance was used for each of the parameters mentioned above. All parameters were affected by prenatal exposure to cocaine. The thickness of the ganglion cell plus nerve fiber layer was reduced in cocaine-exposed rats in comparison with the saline group. Nuclear diameters were smaller in the cocaine than in the saline and control groups. The linear density was higher in the cocaine-exposed group than in the control and saline groups. The age-dependent decrease in the linear density from postnatal day 14-30 was higher in the cocaine-exposed rats than in the saline group; the decrease in the linear density along the centroperipheral axis found in both the control and saline groups was not significant in the cocaine-treated group. These morphometric findings strongly support the view that prenatal cocaine-exposure induces marked changes in the organization of the developing retina.

Effects of prenatal cocaine exposure on postnatal growth patterns of male Wistar rats

The purpose of this study was to investigate basic parameters regarding the postnatal effects of prenatal exposure to cocaine. Timed-pregnant Wistar rats were injected SC with 60 mg/kg body weight/day of cocaine from gestational day 8 to 22. Control females were nonmanipulated and given food and lib; saline females received saline injections and pair-fed received saline and were nutritionally controlled to the cocaine-treated rats. Litters were restricted to 8 pups, weighed every other day until postnatal day (PND) 30 and every week from PND 30 to PND 90. The rats were perfused at PND 14, 30, and 90. The adequacy of adjustment of the logistic and Gompertz models to the body weights of the offspring was tested for the whole experimental period. The results from the Gompertz curve showed a higher growth rate and less time to reach 37% of expected mature body mass for the offspring of cocaine and pair-fed dams as compared with that of control and saline dams. No significant differences in the estimated adult weight were found among the experimental groups. The allometric relationship between forebrain and body weight is described by two postnatal growth phases with a first phase of rapid growth between PND 14 and 30 and a decelerating phase between PND 30 and 90. This relationship was not different among the experimental groups; however, the cocaine and pair-fed offspring showed a constant deficit in the forebrain weight as compared with the control and saline offspring.(ABSTRACT TRUNCATED AT 250 WORDS)

Transient dystonia of infancy, a result of intrauterine cocaine exposure?

Intrauterine cocaine exposure has been associated with multiple transient and permanent neurologic sequelae. Although dystonic reactions have been reported in cocaine users, infantile dystonia following intrauterine exposure has not. We describe 4 infants testing positive for cocaine metabolite at birth with subsequent transient dystonic reactions, beginning at 3 hours to 3 months of age and persisting for several months.

Prenatal cocaine exposure and the development of the human eye

PURPOSE

The use of cocaine during pregnancy has been associated with congenital abnormalities of the developing eye. The authors report a prospective, controlled study of 40 cocaine-exposed and 40 nonexposed (control) preterm and full-term infants.

METHODS

Detailed maternal and obstetric histories were obtained by chart review and interview. Infants with a positive urine toxicology screen for cocaine at birth or whose mothers tested positive for cocaine were recruited into the exposed group. Nonexposed infants were recruited at random from newborns admitted to the authors' nurseries. Mothers of these infants received routine prenatal care in the authors' clinics, and nonexposure was documented by maternal history and/or negative urine toxicologies that were available in 30% of these mother-infant pairs. General physical and ocular examinations, including measurement of axial length and intraocular pressure, were performed on all infants.

RESULTS

Forty infants were recruited in each group, with gestational ages ranging from 25 to 42 weeks. Twenty-nine of the exposed infants and 26 of the control infants were full-term (gestational age, 37 weeks or older). A total of 160 eyes were examined. No differences were seen in the incidence of congenital anomalies, subconjunctival hemorrhages, retinal hemorrhages, or optic nerve abnormalities between the two groups. No differences in mean axial length (16.9 +/- 0.6 mm [exposed group] versus 17.1 +/- 0.7 mm [control group]) or intraocular pressure (15.4 +/- 3.8 mmHg [exposed group] versus 15.0 +/- 3.0 mmHg [control group]) were seen between full-term infants in both groups. Axial length correlated strongly with gestational age, birth weight, head circumference, and body length over the range of gestational ages evaluated in both groups. No effect of cocaine exposure on these correlations was demonstrated. The range of axial length was 12.1 to 18.0 mm in the exposed group and 12.4 to 18.6 mm in the control group.

CONCLUSION

In this study group, no significant effect of prenatal cocaine exposure was seen on the infant eye. In both exposed and nonexposed groups, axial length measurements agreed closely with known statistical norms and correlated closely with other parameters of fetal growth.

Facial features of infants exposed prenatally to cocaine

Thirty two infants referred for in-patient genetics evaluation at the University of California at San Francisco, 1987-1992, were found to have a history of maternal cocaine use. Genetics reports and medical records were reviewed on all these infants to identify features distinctive for cocaine exposure. Among these 32 cases, 14 infants were exposed only to cocaine; 18 were exposed to alcohol and cocaine. The infants evaluated displayed a distinctive phenotype, consisting of neurologic irritability, large fontanels, prominent glabella, marked periorbital and eyelid edema, low nasal bridge with transverse crease, short nose, lateral soft tissue nasal buildup, and small toenails. Features consistent with the fetal alcohol syndrome appeared distinct and coexistent with the other described facial findings. Other severe abnormalities included cleft lip/palate, atypical facial cleft, abnormal BSER, intraventricular hemorrhages, arthrogryposes, and genitourinary abnormalities. Forty percent of the infants were born prematurely; 28% were small for gestational age; 43% showed head circumference values less than the 10th percentile. We conclude that these findings may be distinctive for a diagnosis of fetal cocaine syndrome; such findings should be further established by a future blinded prospective study of mothers and neonates.