Prenatal toxicity of acyclovir in rats

Critical Review of Synthesis, Toxicology and Detection of Acyclovir

Acyclovir (ACV) is an effective and selective antiviral drug, and the study of its toxicology and the use of appropriate detection techniques to control its toxicity at safe levels are extremely important for medicine efforts and human health. This review discusses the mechanism driving ACV’s ability to inhibit viral coding, starting from its development and pharmacology. A comprehensive summary of the existing preparation methods and synthetic materials, such as 5-aminoimidazole-4-carboxamide, guanine and its derivatives, and other purine derivatives, is presented to elucidate the preparation of ACV in detail. In addition, it presents valuable analytical procedures for the toxicological studies of ACV, which are essential for human use and dosing. Analytical methods, including spectrophotometry, high performance liquid chromatography (HPLC), liquid chromatography/tandem mass spectrometry (LC-MS/MS), electrochemical sensors, molecularly imprinted polymers (MIPs), and flow injection–chemiluminescence (FI-CL) are also highlighted. A brief description of the characteristics of each of these methods is also presented. Finally, insight is provided for the development of ACV to drive further innovation of ACV in pharmaceutical applications. This review provides a comprehensive summary of the past life and future challenges of ACV.

Testicular effects following in utero exposure to the antivirals acyclovir and ganciclovir in rats

In utero exposure to the antivirals acyclovir and ganciclovir has been reported to induce gross structural defects in rat offspring. The present study investigated the effects of maternal antiviral treatment on gestation day 10 on reproductive and nonreproductive organs in male rat offspring with a particular focus on the testes. Vehicle and two doses of acyclovir and ganciclovir, 75 and 300 mg/kg, were administered to rat dams. The total doses were fractioned into three subcutaneous applications (3 × distilled water, 3 × 25 mg/kg, and 3 × 100 mg/kg) that were administered on gestation day 10 at 8:00 a.m., 1:00 p.m., and 6:00 p.m. The antiviral concentrations were measured in the serum of the dams 1 h after the last administration. Exposure to 300 mg/kg ganciclovir induced germ cell deficiency in both fetal and adult testes, an effect that was not seen in any other treatment group. Adult rats exposed in utero to this high ganciclovir dose exhibited Sertoli cell-only tubules intermingled with seminiferous tubules that displayed a normal size and normal cell counts, alterations that resemble focal Sertoli cell-only syndrome in humans. The serum concentrations of ganciclovir were markedly higher than those of acyclovir, particularly at the high dose tested. However, although 300 mg/kg acyclovir did not induce germ cell deficiency, other specific effects were seen in exposed animals, including incomplete eye opening and reduced thymus weight.

Antiherpetic medication use and the risk of gastroschisis: findings from the National Birth Defects Prevention Study, 1997-2007

BACKGROUND

Previous studies examining the teratogenic effects of antiherpetic medications have found no associations for birth defects overall but have not examined the risk of specific birth defects.

METHODS

The National Birth Defects Prevention Study ascertains population-based cases with birth defects and live-born controls without birth defects in 10 states across the United States for the purpose of identifying potential teratogenic risk factors. Mothers of cases and controls are interviewed within 2 years of their estimated date of delivery about demographic, medical and behavioural factors before and during pregnancy. This analysis examined the possible association between use of antiherpetic medications (acyclovir, valacyclovir or famciclovir) during early pregnancy and gastroschisis, a birth defect of the abdominal wall.

RESULTS

The mothers of 1.1% (n = 10) of 941 gastroschisis cases and 0.3% (n = 27) of 8339 controls reported antiherpetic medication use during the month before conception through the third month of pregnancy. The adjusted odds ratios for such use in relation to gastroschisis were 4.7 [95% confidence interval 1.7, 13.3] and 4.7 [95% CI 1.2, 19.0] among women with and without self-reported genital herpes, respectively, when compared with women without antiherpetic use or herpes. Among women reporting no antiherpetic medication use, the odds ratio for self-reported genital herpes in relation to gastroschisis was 3.0 [95% CI 1.6, 5.7].

CONCLUSIONS

Our study raises the possibility of an increased risk of gastroschisis because of either antiherpetic medication use during early pregnancy or the underlying genital herpes infection for which it was indicated.

Cytomegalovirus inhibition of embryonic mouse tooth development: a model of the human amelogenesis imperfecta phenocopy

OBJECTIVE

Cytomegalovirus (CMV) is one of the most common causes of major birth defects in humans. Of the approximately 8400 children born each year in the U.S. with CMV-induced birth defects, more than 1/3 of these children exhibit hypoplasia and hypocalcification of tooth enamel. Our objective was to initiate the investigation of the pathogenesis of CMV-induced tooth defects.

DESIGN

Mouse Cap stage mandibular first molars were infected with mouse CMV (mCMV) in vitro in a chemically-defined organ culture system and analysed utilising histological and immunolocalisation methodologies. The antiviral, acyclovir, was used to inhibit mCMV replication and comparisons made between mCMV-infected and acyclovir-treated, mCMV-infected teeth.

RESULTS

Active infection of Cap stage molars for up to 15 days in vitro results in smaller, developmentally-delayed and dysmorphic molars characterised by shallow, broad and misshapen cusps, infected and affected dental papilla mesenchyme, poorly differentiated odontoblasts and ameloblasts, and no dentin matrix. Initial protein localisation studies suggest that the pathogenesis is mediated through NF-kappaB signaling and that there appears to be an unusual interaction between abnormal mesenchymal cells and surrounding matrix. Rescue with acyclovir indicates that mCMV replication is necessary to initiate and sustain progressive tooth dysmorphogenesis.

CONCLUSIONS

Our results indicate that mCMV-induced changes in signaling pathways severely delays, but does not completely interrupt, tooth morphogenesis. Importantly, our results demonstrate that this well-defined embryonic mouse organ culture system can be utilised to delineate the molecular mechanism underlying the CMV-induced tooth defects that characterise the amelogenesis imperfecta phenocopy seen in many CMV-infected children.

Cytomegalovirus-induced embryopathology: mouse submandibular salivary gland epithelial-mesenchymal ontogeny as a model

BACKGROUND

Human studies suggest, and mouse models clearly demonstrate, that cytomegalovirus (CMV) is dysmorphic to early organ and tissue development. CMV has a particular tropism for embryonic salivary gland and other head mesenchyme. CMV has evolved to co-opt cell signaling networks so to optimize replication and survival, to the detriment of infected tissues. It has been postulated that mesenchymal infection is the critical step in disrupting organogenesis. If so, organogenesis dependent on epithelial-mesenchymal interactions would be particularly vulnerable. In this study, we chose to model the vulnerability by investigating the cell and molecular pathogenesis of CMV infected mouse embryonic submandibular salivary glands (SMGs).

RESULTS

We infected E15 SMG explants with mouse CMV (mCMV). Active infection for up to 12 days in vitro results in a remarkable cell and molecular pathology characterized by atypical ductal epithelial hyperplasia, apparent epitheliomesenchymal transformation, oncocytic-like stromal metaplasia, beta-catenin nuclear localization, and upregulation of Nfkb2, Relb, Il6, Stat3, and Cox2. Rescue with an antiviral nucleoside analogue indicates that mCMV replication is necessary to initiate and maintain SMG dysmorphogenesis.

CONCLUSION

mCMV infection of embryonic mouse explants results in dysplasia, metaplasia, and, possibly, anaplasia. The molecular pathogenesis appears to center around the activation of canonical and, perhaps more importantly, noncanonical NFkappaB. Further, COX-2 and IL-6 are important downstream effectors of embryopathology. At the cellular level, there appears to be a consequential interplay between the transformed SMG cells and the surrounding extracellular matrix, resulting in the nuclear translocation of beta-catenin. From these studies, a tentative framework has emerged within which additional studies may be planned and performed.

The Use of Dermatologic Drugs in Pregnancy and Lactation

Physicians are generally reluctant to prescribe dermatologic drugs to pregnant or nursing women because treatment is often elective and can be harmful to the patient, her fetus, or nursing infant; concerns for potential litigation also give pause. Yet, some effective dermatologic drugs have been determined to be safe during pregnancy and lactation. Of great practicality is an easily accessed reference guide that condenses information on such drugs into a set of tables that list pregnancy and teratogenicity ratings. Indications and contraindications are ordered in relation to the phases and trimesters of pregnancy. A discussion of the necessity of considering stages of childbearing in choosing drug therapies introduces the tables. A summary list of cautions spells out the steps physicians should take in treating women of childbearing age.

Pregnancy outcomes following systemic prenatal acyclovir exposure: Conclusions from the international acyclovir pregnancy registry, 1984-1999

BACKGROUND

Oral acyclovir is commonly used for genital herpes and other herpesvirus infections. Data on potential fetal risk are extremely limited. From 1984 to 1998, the Acyclovir in Pregnancy Registry monitored birth outcomes of women exposed to oral or intravenous acyclovir during pregnancy. This report describes the final results.

METHODS

The registry was publicized to health care providers most likely to diagnose pregnancy; providers called the registry telephone number, then mailed in a brief questionnaire. Pregnancy outcomes were categorized either as outcomes with birth defects or outcomes without birth defects, subcategorized as live births, spontaneous pregnancy losses (including stillbirths), and induced abortions. Birth defects were defined using a modification of the CDC definition for birth defects surveillance systems. Observed rates were compared to the rate (3.2%) of birth defects expected in the general population.

RESULTS

Between June 1, 1984 and June 30, 1998, 1695 pregnancies exposed to oral or IV acyclovir were registered; 461 (27%) were lost to follow-up. A total of 1234 pregnancies in 24 countries were followed, with a total of 1246 outcomes. Among 1246 pregnancy outcomes, 756 involved acyclovir exposure in the first trimester, 197 in the second trimester, and 291 in the third trimester. Among live births with first trimester acyclovir exposure, risk of birth defects was 19 of 596 (3.2%; 95% CI, 2.0-5.0%). No unusual defects or pattern of defects were apparent.

CONCLUSIONS

The observed rates and types of birth defects for pregnancies exposed to acyclovir did not differ significantly from those in the general population. Birth Defects Research (Part A), 2004. Published 2004 Wiley-Liss, Inc.

Adverse pregnancy outcome in women exposed to acyclovir during pregnancy: a population-based observational study

This study aimed to examine the risk of adverse pregnancy outcomes in children born to mothers who redeemed a prescription for systemic or topical acyclovir during pregnancy. Data on prescriptions of acyclovir were obtained from the Danish North Jutland Prescription Database and data on pregnancy outcomes from the Danish Medical Birth Registry and the County Hospital Discharge Registry. The risk of malformations, low birth weight, preterm birth and stillbirth in users of acyclovir were compared with non-exposed women using a follow-up design, while the risk of spontaneous abortion was examined using a case-control design. 90 pregnant women had redeemed a prescription for systemic acyclovir, and 995 women for topical acyclovir, during 30 d before conception, or during their pregnancies from 1 January 1990 to 31 December 2001. The odds ratios (95% confidence intervals) of the exposed relative to the non-exposed for the systemic and topical acyclovir were: malformations, 0.69 (0.17-2.82) and 0.84 (0.51, 1.39); low birth weight, 2.03 (0.50-8.35) and 0.48 (0.21-1.07); preterm birth, 1.04 (0.38-2.85) and 0.95 (0.70-1.28); stillbirth (for topical acyclovir), 1.70 (0.80-3.60); and spontaneous abortion, 2.16 (0.60-7.80) and 1.29 (0.80-3.60). There is increasing evidence that the use of systemic acyclovir is not associated with an increased prevalence of malformations at birth and preterm delivery. The data for low birth weight and spontaneous abortion are still inconclusive, although the risk of spontaneous abortion is increased in women exposed to acyclovir during the first month of pregnancy. The use of topical acyclovir does not seem to be associated with any adverse pregnancy outcome, although data on stillbirth are inconclusive.

Test systems to identify reproductive toxicants

Experience with drugs and other xenobiotics indicates that both animal testing and epidemiological studies are necessary to provide adequate data for an estimation of risks that might be associated with exposure to a chemical substance. In this review, the pros and cons of test systems for reproductive toxicity are discussed. Usually, several studies are performed to cover the different phases of the reproductive cycle. In the preclinical development of drugs, the three so-called 'segment testing protocols' have been used for several decades now. More recently, new testing concepts have been accepted internationally which include more flexibility in implementation. Several examples of compounds with the potential for reproductive toxicity are presented in more detail in a discussion of some pitfalls of the tests for fertility (phthalates and fluoroquinolones), teratogenicity (acyclovir and protease inhibitors) and postnatal developmental toxicity (fluoroquinolones). In addition, important aspects of kinetics and metabolism as a prerequisite for a rational interpretation of results from toxicological studies are briefly discussed. In vitro assays are useful for supplementing the routinely used in vivo approaches or for studying an expected or defined effect, but they are not suitable for revealing an unknown effect of a chemical on the complex reproductive process.

Vulnerability of the endocrine system to xenobiotic influence

Natural sex hormones are most important factors guaranteeing the homeostasis of male and female sexual functions, including sexual differentiation and reproduction. Main target tissues include bone and skin, cardiovascular system, and possibly central nervous and immune systems. In medicine, synthetic hormonal substances with agonistic and antagonistic properties have been widely used for decades. Therapeutic benefit is the aim, and the many possibilities to interfere with normal or pathological hormonal situations are rather well understood. Synthetic hormonal agonists or (partial) antagonists may exhibit specific affinities to special receptors resulting in a spectrum of organotropies, or they may even induce opposite actions on different targets. Although not a new issue, environmental substances mimicking potentials of sex hormones have recently gained increased attention. There is not need to reinvent the wheel, since most (adverse) effects may be revealed with today's routine procedures used for testing medicinal substances, but some additional testing strategies should be included. Adverse effects of ecohormones may preferentially affect systems other than the human organism (assuming lower exposure and possibly lower susceptibility). Nevertheless, this survey is confined to possible alterations in the mammalian organism, since such effects are best understood from numerous experimental studies and clinical trials.

Effects observed on gestational day 13 in rat embryos exposed to albendazole

Albendazole (ABZ) was utilized as a model to investigate the pathogenesis of benzimidazole-induced abnormalities. Pregnant Sprague-Dawley rats were treated po with 0, 10, 20, and 30 mg/kg on gestational days (GD) 10 to 12. The embryos were examined on GD 13, as a window for observing the origin of alterations detected at term. Embryolethality and growth reduction showed dose-related increases at the three dose levels. At 10 mg/kg, an increased developmental delay of limb buds and a less than 5% incidence of embryos with abnormal head or shape were detected. At 20 and 30 mg/kg, > 20% of embryos showed morphologic alterations involving mainly shape abnormalities and the development of forelimb buds, branchial bars, eye, and telencephalon; closure of neuropores was unaffected. Dose-response relationships for morphologic alterations showed steeper slopes than for growth reduction and embryolethality.

Chronic effects of azidothymidine and acyclovir on pregnant rats

1. The antiviral effect of azidothymidine (AZT) can be potentiated by acyclovir (ACV), and this drug association has been used in the management of HIV-infected patients. In the present study we examined the effects of such an association on rat pregnancy. 2. AZT (60 mg/kg b.w.) and ACV (60 mg/kg b.w.) were given to groups of pregnant rats once a day from the 1st to the 20th day of gestation. 3. Maternal body weight gain was severely affected by ACV; this effect was attenuated in rats treated with AZT+ACV and was virtually absent with AZT alone. 4. The abortive action of ACV was markedly diminished in the group treated with the association AZT+ACV. 5. The deleterious effects of ACV on rat pregnancy are presumably due to its extraplacental actions, and these are, at least in part, counteracted by concomitant treatment with AZT.

Significance of embryo culture methods for studying the prenatal toxicity of virustatic agents

Culture methods have become important tools for elucidating the prenatal toxicity of drugs and other xenobiotics. In this paper we will review how we used in vitro as well as in vivo approaches to demonstrate the teratogenic potential of aciclovir and other related virustatic agents. In addition, some new data on this topic will be given. The teratogenic potential of the virustatic agent aciclovir was not recognized in routinely performed segment-II-studies, but the first indication came from experiments with the culture of rat embryos. Subsequently, the findings were confirmed in modified in vivo tests and it became clear that out of a group of six related drugs aciclovir exhibited the highest potential for prenatal toxicity. The effects of aciclovir on limb development were not pronounced--this has been shown with in vitro and in vivo experiments as well. In vivo experiments first indicated that the prenatal development of the thymus is disturbed by aciclovir. This effect was further studied with the culture of fetal thymuses and again the effect of aciclovir could be compared with related drugs. In summary, our work with virustatics during the last years has shown that in vivo and in vitro approaches are by no means competitive and that a combination of both approaches can provide a solid basis for a toxicologic evaluation.

Congenital neonatal herpes simplex virus infection

Intrauterine-acquired neonatal herpes simplex virus infection is a severe, often life-threatening infection that has a wide spectrum of clinical presentations. We describe a 31-week-gestation male who had a rarely reported epidermolysis bullosa-like clinical presentation. He acquired herpes simplex virus type II in utero secondary to a primary maternal infection that occurred on the knee. A review of the infection, the need for early therapy, and the prognosis are presented.

Abnormal thymus development and impaired function of the immune system in rats after prenatal exposure to aciclovir

Aciclovir (synonym: acyclovir) causes abnormal thymus development in rats. After treatment on day 10 of gestation a weight reduction of the organ is obvious in 21-day-old fetuses which persists postnatally. Adult male rats exposed in utero to one or three injections of 100 mg aciclovir/kg body wt given to the dam on day 10 of pregnancy showed a reduction of the thymus weight to 333 +/- 158 mg and 276 +/- 61 mg (control: 428 +/- 92 mg; n = 10). Corresponding alterations were detectable in female offspring. Liver weight was also decreased and spleen weight (in relation to body wt) was significantly increased in the offspring after the three exposures. In a host resistance model with Trichinella spiralis the function of the immune system of rats prenatally exposed to aciclovir was examined. Six weeks postnatally 10-12 randomly selected male rat offspring of one control and two treatment groups (1 or 3 injections of 100 mg aciclovir/kg body wt on day 10 of gestation) were infected orally with 500 Trichinella spiralis muscle larvae. Before and several times after the infection blood was taken from a tail vein or obtained by decapitation for examination of the antibody titers (IgM, IgG, IgA, IgE) to antigens of T. spiralis. Six weeks after the infection the weight of relevant organs was determined and tongue preparations were used for T. spiralis muscle larvae counting. Aciclovir exposed animals showed a different immune response than control rats. IgM titers in both treatment groups were higher than in controls two weeks after the infection but not different by the end of the experiment.(ABSTRACT TRUNCATED AT 250 WORDS)

Nephrotoxicity of acyclovir and cis-diamminedichloroplatinum(II)--effect of co-administration in rats

The effect of co-administration of acyclovir and cis-diamminedichloroplatinum(II) (cisplatin) on nephrotoxicity in male Wistar rats was investigated. Animals received acyclovir (15 mg/kg body weight, s.c., three times per day for 5 days) or cisplatin (5 mg/kg body weight, i.p., one single injection) or a combination of both drugs. Acyclovir plasma levels were determined after one single acyclovir s.c. injection. Urines were monitored for volume, pH, osmolality and excretion of N-acetyl-beta-D-glucosaminidase (NAG), lysozyme and total protein. Concentrations of blood urea nitrogen and plasma creatinine were determined on day 6. Renal cortical slices were monitored to assess the accumulation of weak organic bases (tetraethylammonium) and acids (p-aminohippurate). Cisplatin induced a marked increase in the excretion of NAG, lysozyme and total protein and an increase in urine volume, plasma creatinine and blood urea nitrogen. Urine osmolality and accumulation of p-aminohippurate were depressed by cisplatin. Acyclovir treatment alone caused no significant symptoms of nephrotoxicity. Co-administration did not impair renal function more than cisplatin treatment alone, excepting a slight rise in lysozyme excretion on day 6. Short-term antiviral therapy with acyclovir, concomitant to cisplatin treatment, may bring, if at all, a slightly increased nephrotoxic risk.

Effect of aciclovir on the development of the chick embryo in ovo

The effect of aciclovir (ACV) on embryonic development was investigated using the chick embryo in ovo and treatment during organogenesis. ACV 30-1000 micrograms was applied as single doses prior to or after 24 h of incubation into the yolk sac, and ACV 3-100 micrograms after 2, 3 or 4 days of incubation (DI) directly to the embryo. Data were evaluated after a total of 8 days of incubation. (1) A dose-related increase in the rate of abnormal development was found in the surviving embryos. Depending on the route of drug administration a dose of 300, respectively, 5 micrograms ACV/egg had to be applied to induce 50% abnormal development. (2) Gross structural abnormalities of the surviving embryos mainly concerned the beak and the extremities. With the experimental set-up used a different pattern of abnormalities in the survivors after treatment at various stages could not be observed. The results are compared with data obtained with ACV in rodents in our laboratory. It is suggested that chick embryos are also capable of converting ACV into its triphosphate to interfere with DNA metabolism, probably through a chain break mechanism.

In vitro and in vivo studies on the prenatal toxicity of five virustatic nucleoside analogues in comparison to aciclovir

Several virustatic agents are known to be teratogenic in laboratory animals. Since routinely performed in vivo studies do not always offer the best conditions to detect the teratogenic potential of a drug, we used a combined in vivo/in vitro approach for comparative studies on the prenatal toxicity of five nucleoside analogues. Rat embryos were exposed for 48 h to various concentrations of vidarabine-phosphate (VAP), ganciclovir (GCV), 2',3'-dideoxyadenosine (ddA), 2',3'-dideoxycytidine (ddC) and zidovudine (= azidothymidine, AZT) in a whole-embryo culture system. The steepness of the concentration-response curves as well as the induced abnormality pattern (head, neural tube, shape) were similar for these compounds. However, a wide range in embryotoxic potency was observed: VAP was the most potent compound (100% abnormal embryos at 25 microM) in this in vitro system, while AZT showed the lowest potency to interfere with normal embryonic development (40% abnormal embryos at 3000 microM). In addition to these experiments we treated rats on day 10 of gestation with three s.c. injections (8 a.m.; 12 a.m.; 4 p.m.) of 200 mg of each drug/kg body wt. The embryos were evaluated on day 11.5 of gestation, i.e. at a time of development corresponding to the developmental stage at the end of the whole-embryo culture. The same criteria were used as during the in vitro studies for the evaluation of these in vivo exposed embryos. With VAP and GCV we obtained similar results with both exposure routes (in vitro and in vivo), while no abnormalities were detectable with the other compounds after exposure in utero.(ABSTRACT TRUNCATED AT 250 WORDS)

Whole embryo culture: interpretation of abnormal development in vitro

An overview will be given of a number of problems that arise when we attempt an interpretation of data obtained with the whole embryo culture method (WEC). The following aspects will be considered: 1) Types of deviation from normal development in the whole-embryo culture system: (a) problem of "artifacts" (for example, due to preparation mistakes and suboptimal culture conditions), (b) types and frequency of abnormal development in controls, retardation as an abnormal outcome, and the difficulty of assessing its significance, (c) gross-structural defects and, specifically, attempts to answer the following questions: (i) What are the limitations for an assessment of abnormal development with the WEC? (ii) Is a specific abnormality pattern recognizable under specific pathologic conditions? (iii) Is the rate of induced abnormal development concentration-dependent? (2) Problems encountered when interpreting concentration-effect relationships (for example, statistical and pharmacokinetic aspects). (3) Necessity of verifying in vitro effects with in vivo studies.

Effects of valproic acid, some of its metabolites and analogues on prenatal development of rats in vitro and comparison with effects in vivo

Using a whole-embryo culture system valproic acid (VPA) and some of its metabolites (2-en-VPA, 4-en-VPA, 4,4'-dien-VPA) and analogues (ethyl-propyl-acetic acid, propyl-butyl-acetic acid, di-butyl-acetic acid, 2-methyl-2-ethyl-hexanoic acid, 1-methyl-1-cyclohexanoic acid) were tested for their potential to induce abnormal development. With regard to embryonic growth, development and abnormality rate, the tested compounds showed a wide range of "teratogenic potency" in vitro. In order to verify some of the in vitro results, in vivo experiments were performed. Pregnant rats were treated subcutaneously on day 10 of gestation with 2 x 330 mg VPA/kg, or 2 x 400 mg 2-en-VPA/kg, respectively. Evaluation of the embryos was performed on day 11.5 of gestation, corresponding to the in vitro experiments. VPA showed a high potential to induce abnormal development in vivo as well as in vitro, whereas 2-en-VPA was inactive under our experimental conditions. Problems connected with the evaluation of the predictive value of an in vitro test system for the detection of embryotoxic effects, such as "validation" and significance of pharmacokinetic data, are discussed.

Hypertension and nephrotoxic lesions in rats 1 year after prenatal exposure to gentamicin

Using the aminoglycoside antibiotic gentamicin persistent functional and morphological changes were induced prenatally in the rat kidney. After 6 days of s.c. treatment (110 mg gentamicin/kg body wt) from day 10 to 15 of pregnancy complete resorption was noticed in 8 of the 14 treated animals. Fifty-three newborn were obtained from six dams. One year later only 26 rats (16 male, 10 female) were still alive. The systolic arterial pressure of the female offspring was significantly increased (139 +/- 15 mm Hg versus 112 +/- 9 mmHg) compared with controls. No statistically significant effect could be noticed in the male offspring (128 +/- 15 mm Hg versus 118 +/- 21 mm Hg). Corresponding results were obtained from analysis of urea plasma concentrations. Another cohort of pregnant rats received daily injections of gentamicin from day 15 to 20 of pregnancy (110 mg/kg body wt s.c.). In this group 59 newborn from a total of 109 died within the first 5 days after birth. Six litters were observed postnatally. One year after birth the following blood pressure values were determined: 122 +/- 14 mm Hg (male) and 132 +/- 17 mm Hg (female). Urea plasma concentrations were significantly higher in female, but not in male, offspring. Light and electron microscopic inspection revealed pathological changes in the kidneys of the female offspring only. The degree of maternal kidney damage - which shows considerable variations - was monitored during the treatment period. For this purpose the plasma gentamicin and urea concentrations were measured on 3 days of treatment in all of the pregnant animals. The postnatal data (mortality, blood pressure, and urea plasma concentrations) show a correlation to the degree of maternal kidney impairment.

Gross-structural defects in rats after acyclovir application on day 10 of gestation

Following three s.c. injections of acyclovir (100 mg acyclovir/kg) into rats on day 10 of pregnancy 19 litters were evaluated on day 21 of gestation and the effects were compared to the results obtained from controls (nine litters) which received the vehicle (0.1 N NaOH) only. The following results were obtained (treated group versus control group): 1) Implantations/litter: 11.2 +/- 1.3 versus 10.2 +/- 1.1; 2) resorptions/implantations: 27.7% versus 2.2%; 3) number of viable fetuses evaluated: 154 versus 90; 4) fetuses with anomalies of the skull: 78% versus 12%; 5) fetuses with anomalies of the vertebral column: 38% versus 13%; 6) gross-structural anomalies predominantly affected the skull and tail. The most frequently registered defects were: os tympanicum (smaller): 23%, os tympanicum (missing): 23%; missing tail: 7%; protruding tongue (15%); none of these defects were seen in the control fetuses. Postnatally we observed a high mortality rate among the offspring. From a total of 85 newborn (nine litters) we obtained 73 viable offspring (9.1 +/- 3.4); 81% of them had tail alterations. In the control group of eight litters (9.4 +/- 2.3) no tail alterations occurred. On day 21 postnatally 40 viable offspring were alive (mortality rate: 38.8%). Nearly all of these animals had visible alterations at multiple sites of their bodies; most frequently observed were: tail impairment, closed eyes, dragging hind-limbs, and urogenital alterations (e.g. testicular atrophy). These studies how for the first time that prenatal treatment with acyclovir induces gross-structural defects which persist postnatally.(ABSTRACT TRUNCATED AT 250 WORDS)