Prior differences in previous trauma exposure primarily drive the observed racial/ethnic differences in posttrauma depression and anxiety following a recent trauma

BACKGROUND

Racial and ethnic groups in the USA differ in the prevalence of posttraumatic stress disorder (PTSD). Recent research however has not observed consistent racial/ethnic differences in posttraumatic stress in the early aftermath of trauma, suggesting that such differences in chronic PTSD rates may be related to differences in recovery over time.

METHODS

As part of the multisite, longitudinal AURORA study, we investigated racial/ethnic differences in PTSD and related outcomes within 3 months after trauma. Participants (n = 930) were recruited from emergency departments across the USA and provided periodic (2 weeks, 8 weeks, and 3 months after trauma) self-report assessments of PTSD, depression, dissociation, anxiety, and resilience. Linear models were completed to investigate racial/ethnic differences in posttraumatic dysfunction with subsequent follow-up models assessing potential effects of prior life stressors.

RESULTS

Racial/ethnic groups did not differ in symptoms over time; however, Black participants showed reduced posttraumatic depression and anxiety symptoms overall compared to Hispanic participants and White participants. Racial/ethnic differences were not attenuated after accounting for differences in sociodemographic factors. However, racial/ethnic differences in depression and anxiety were no longer significant after accounting for greater prior trauma exposure and childhood emotional abuse in White participants.

CONCLUSIONS

The present findings suggest prior differences in previous trauma exposure partially mediate the observed racial/ethnic differences in posttraumatic depression and anxiety symptoms following a recent trauma. Our findings further demonstrate that racial/ethnic groups show similar rates of symptom recovery over time. Future work utilizing longer time-scale data is needed to elucidate potential racial/ethnic differences in long-term symptom trajectories.

C-55 Normal Brain Cells in Abnormal Places: Contributions of Conjoint Neuropsychological, Pediatric, Neurologic, and Psychiatric Assessment in the Diagnosis and Behavioral Management of Pediatric Subependymal Heterotopia

Objective

Subependymal heterotopia (SH) is a development brain malformation from abnormal neuronal proliferation and migration resulting in developmental delays and focal childhood epilepsy (Barkovich, 2000). SH results from the interruption of normal gray matter migration beneath the ependyma of the lateral ventricles. Most males are spontaneously aborted, and although there is some genetic uncertainty, affected females are thought to be X-linked (Xq28) recessive (Mitchell, et.al., 2000). SH prevalence in epileptic children with brain dysgenesis is between 13-20% and manifests in motor, visual-spatial, cognitive, and psychological deficits (Data, et.al., 2018).

Method

We present a case study of a seventeen-year-old female who was diagnosed at age eight with ADD and LD by self-report check-lists and achievement tests. Behavioral irregularities and seizure onset lead pediatrics to request neuropsychological testing. Findings revealed cognitive and emotional impairment and consequently further medical evaluation was recommended. Pediatric, neurological, and psychiatric examination, EEG, and MRI confirmed SH along the lateral margin of the right lateral ventricle.

Results

Psychometric testing revealed low average FSIQ, PRI, and PSI, impaired arithmetic operations and problem solving, graphomotor deficits, motor speed and executive/planning difficulties, emotional dysregulation, age-inappropriate interpersonal skills, and social-behavioral regression.

Conclusions

Neuropsychological assessment provided clear evidence of cognitive impairment beyond the initial diagnoses, suggested lateralized dysfunction, and implicated frontal and subcortical behavioral correlates not explained by other dispositional variables. Comprehensive neuropsychological assessment provided detailed information toward conjoint treatment planning by pediatrics, neurology, psychology, psychiatry, and teachers. Findings provided meaningful diagnostic clarification of SH and furthered clinical understanding of this adolescent’s social, academic, neuropsychological, and psychiatric needs.

MRI-guided, open trial of abciximab for ischemic stroke within a 3- to 24-hour window

The authors assessed the effect of IV abciximab on early neurologic improvement and ischemic lesion growth in 29 patients with supratentorial stroke and NIH stroke scale score (NIHSSS) > or = 4 (11.1 +/- 5.9), treated within 3 to 24 (13.6 +/- 5.5) hours of onset. The 48 to 72-hour NIHSSS improvement was 4.4 +/- 3.2 and the 24-hour lesion growth on DWI was +23% (-50%, +103%); 7/26 (27%) patients experienced lesion size decrease. Treatment of sub-24-hour stroke with abciximab improves early post-treatment neurologic status and often attenuates ischemic lesion growth.

Treatment of acute ischemic stroke

Acute ischemic stroke is the third leading cause of death in the United States and the leading cause of adult disability. The direct and indirect costs of stroke care exceed $51 billion annually. In 1996, the US Food and Drug Administration approved the first treatment for acute ischemic stroke, intravenous tissue plasminogen activator. Later that year, the National Institute of Neurologic Disorders and Stroke (a branch of the National Institutes of Health) convened a consensus conference on the Rapid Identification and Treatment of Acute Ischemic Stroke, setting goals for stroke care in the United States. Since then, it has become imperative that emergency physicians understand the pathophysiology of stroke, the basis and rationale for treatment, and the therapeutic approaches. This article reviews the state of the art of acute stroke treatment, its foundation, as well as its future.

Recombinant chemosensory protein (CSP2) from the moth Mamestra brassicae: crystallization and preliminary crystallographic study

Chemosensory proteins (CSPs) are small proteins (13 kDa on average) present in several sensory organs from a wide range of insect species. They are believed to be involved in chemoperception (olfaction or taste) and to play a role in chemical transport from air or water to chemosensitive receptors. Here, the first crystals of a CSP originating from the moth Mamestra brassicae (Mbra) proboscis and expressed as recombinant protein in Escherichia coli periplasm are reported. Crystals of MbraCSP2 were obtained by the hanging-drop vapour-diffusion method under the following conditions: 1 microl of a 46 mg ml(-1) protein solution in 50 mM Tris pH 8.0 containing cetyl alcohol as ligand (1:5 molar ratio) was mixed with 1 microl of well solution containing 30% PEG 4000, 0.2 M sodium acetate in 100 mM Tris at pH 8.4. The protein-cetyl alcohol complex crystallizes in space group P2(1), with unit-cell parameters a = 47.9, b = 49.7, c = 50.3 A, beta = 110.1 degrees. With two molecules in the asymmetric unit, the V(M) is 2.15 A(3) Da(-1) and the solvent content is 42%. A complete data set has been collected at 1.6 A resolution on beamline ID14-2 (ESRF, Grenoble). Se-Met expression has been performed with a view to solving the CSP2 structure with MAD data collection using the Se absorption edge.

Tobacco mosaic virus inoculation inhibits wound-induced jasmonic acid-mediated responses within but not between plants

Jasmonic acid (JA) and salicylic acid (SA) have both been implicated as important signal molecules mediating induced defenses of Nicotiana tabacum L. against herbivores and pathogens. Since the application of SA to a wound site can inhibit both wound-induced JA and a defense response that it elicits, namely nicotine production, we determined if tobacco mosaic virus (TMV) inoculation, with its associated endogenous systemic increase in SA, reduces a plant's ability to increase JA and nicotine levels in response to mechanical damage, and evaluated the consequences of these interactions for the amount of tissue removed by a nicotine-tolerant herbivore, Manduca sexta. Additionally, we determined whether the release of volatile methyl salicylic acid (MeSA) from inoculated plants can reduce wound-induced JA and nicotine responses in uninoculated plants sharing the same chamber. The TMV-inoculated plants, though capable of inducing nicotine normally in response to methyl jasmonate applications, had attenuated wound-induced JA and nicotine responses. Moreover, larvae consumed 1.7- to 2.7-times more leaf tissue from TMV-inoculated plants than from mock-inoculated plants. Uninoculated plants growing in chambers downwind of either TMV-inoculated plants or vials releasing MeSA at 83- to 643-times the amount TMV-inoculated plants release, exhibited normal wound-induced responses. We conclude that tobacco plants, when inoculated with TMV, are unable to elicit normal wound responses, due likely to the inhibition of JA production by the systemic increase in SA induced by virus-inoculation. The release of volatile MeSA from inoculated plants is not sufficient to influence the wound-induced responses of neighboring plants.

A molecular study of euglenoid phylogeny using small subunit rDNA

The euglenoids are an ancient and extremely diverse lineage of eukaryotic flagellates with unclear relationships among taxa. Synapomorphies for the euglenoids include a surface pellicle and a closed mitosis with a series of separate sub-spindles. The taxonomy currently in use is inconsistent with the available data and needs revision. Most euglenoid phylogenies are largely intuitive reconstructions based on a limited number of morphological characters. Therefore, we have added molecular characters from the Small Subunit (SSU) rDNA to generate an overall phylogenetic framework for the euglenoids. SSU rDNA sequences from photosynthetic, osmotrophic, and phagotrophic euglenoids were aligned based on secondary structure. Phylogenetic analysis using the conserved areas of the sequence was performed using parsimony, maximum likelihood, and distance methods. Trees derived using different criteria are in agreement. The euglenoids form a distinct monophyletic clade with phagotrophic members diverging prior to the phototrophic and osmotrophic members. Among photosynthetic members, the biflagellate form diverged prior to the uniflagellate form. Additionally, the genus Euglena appears to be paraphyletic, with osmotrophic taxa, such as Astasia and Khawkinea, diverging independently within the clade containing the photosynthetic genus Euglena.

Hypertension and its treatment in the NINDS rt-PA Stroke Trial

BACKGROUND AND PURPOSE

We examined the frequency, course, and treatment of hypertension in the NINDS rt-PA Stroke Trial.

METHODS

Blood pressure (BP) was measured at the time of admission, at randomization, and then 36 times during the first 24 hours after randomization. Patients with a systolic BP of >185 mm Hg and a diastolic BP of >110 mm Hg at admission were defined as hypertensive before randomization, and those with a systolic BP of >180 mm Hg or a diastolic BP of >105 mm Hg within the first 24 hours after randomization were defined as hypertensive after randomization. Standardized clinical assessments were conducted at 24 hours and at 3 months. Post hoc analyses were conducted to evaluate the association of antihypertensive therapy with clinical outcomes.

RESULTS

Of the 624 patients, 121(19%) had hypertension on admission and 372 (60%) had hypertension in the 24 hours after randomization. The use of antihypertensive therapy before randomization (tPA 9%, placebo 9%) and after randomization (tPA 24%, placebo 29%) was similar between placebo- and tPA-treated patients. No adverse effects of prerandomization antihypertensive therapy on 3-month favorable outcome were detected for either the placebo- or tPA-treated groups. For placebo patients with hypertension in the 24 hours after randomization, clinical outcome measures were similar for those patients who did and did not receive antihypertensive therapy after randomization (P > or = 0.26); antihypertensive therapy was not associated with declines in BP (P = 0.44) or with abrupt declines (P = 0.14). Those tPA patients who were hypertensive after randomization and received antihypertensive therapy were less likely to have a favorable outcome at 3 months (P < 0.01) than those who were hypertensive and did not receive antihypertensive therapy.

CONCLUSIONS

The frequency of hypertension and the use of antihypertensive therapy were similar between the tPA and placebo groups in the NINDS rt-PA Stroke Trial. In the placebo group, antihypertensive therapy was not associated with less favorable outcomes at 3 months; postrandomization antihypertensive therapy was associated with less favorable outcomes for the tPA patients who were hypertensive. However, because of the nonrandomized use of antihypertensive therapy and the many post hoc comparisons leading to type 1 errors, the significance of this observation is unclear. Careful attention to BP and gentle management remain warranted for stroke patients treated with tPA.

Post-hoc Rasch analysis of optimal categorization of an ordered-response scale

The purpose of this study was to determine the optimal categorization of a self-efficacy ordered-response scale using the Rasch analysis and compare the performance of the Rasch statistics and parameter estimates with conventional statistics. A 50-item scale to measure psychomotor self-efficacy was administered to a total of 2,022 children, including 1,009 boys and 1,013 girls. The data analysis started by collapsing the original five adjacent categories into two, three, and four categories, and a total of 14 data sets were derived. Each of these data sets, including the original one, was analyzed using the Rasch rating scale model, and a set of Rasch model-data fit, category, and separation statistics and parameter estimates, as well as three conventional statistics, were computed and compared. It was found that, instead of the five-category construct designed, the best order of category meanings of the scale in respondents' perceptions was a three-category construct. The Rasch threshold estimates were sensitive indexes in determining the order of the categorization, and that item separation statistics were useful in determining the optimal categorization after its order was confirmed. The commonly used coefficient alpha was found not helpful at all in determining the optimal categorization. The Rasch analysis was demonstrated to be a useful post-hoc analytic approach in determining the optimal categorization of an ordered-response scale.

Nutritional rickets among breast-fed black and Alaska Native children

Although nutritional rickets remains a problem primarily in developing countries, children in northern climates in developed countries may also be at risk. We reviewed the case histories of five children diagnosed in Alaska during 1993-96. Three of the children were black and two Alaska Native. Their ages ranged from 11 to 20 months and they presented during January, April, and September. All of the children were breast-fed but only two received their milk intake exclusively from breast milk. The presenting complaint included abnormal gait in two children and seizures, bowed legs, and growth delay in one child each. All five children demonstrated a decrease in their height-for-age percentile. The most common physical finding was a rachitic rosary which was present in four children. In Alaska, all black and Alaska Native children (and other more pigmented children) less than two years of age who receive all or part of their milk intake from breast milk should receive vitamin D supplementation regardless of the time of year.

A technique revisited: hemodynamic comparison of closed- and open-chest cardiac massage during human cardiopulmonary resuscitation

OBJECTIVE

To compare the hemodynamics of closed-chest cardiac massage vs. open-chest cardiac massage in patients resuscitated from cardiac arrest that occurred outside of the hospital.

DESIGN

Prospective, non-outcome, case series.

SETTING

Large urban emergency department.

PATIENTS

Ten adult, normothermic, nontraumatic, out-of-hospital, cardiac arrest patients who failed advanced cardiac life support (ACLS) therapy.

INTERVENTIONS

Patients presenting to the hospital in cardiac arrest were managed according to the ACLS protocol at the clinician's discretion. Proximal aortic and central venous pressure catheters were placed to measure arteriovenous compression- and relaxation-phase pressure gradients. After 5 mins of baseline measurements during closed-chest cardiac massage, patients underwent a left lateral thoracotomy, and open-chest cardiac massage was performed for 5 mins.

MEASUREMENTS AND MAIN RESULTS

The mean coronary perfusion pressure and compression-phase pressure gradients were 7.3 +/- 5.7 and 6.2 +/- 5.4 mm Hg, respectively, during closed-chest cardiac massage, while increasing to 32.6 +/- 17.8 and 32.6 +/- 29.9 mm Hg, respectively, during open-chest cardiac massage. The differences between both measurements were statistically significant (p < .05).

CONCLUSIONS

Open-chest cardiac massage is superior to closed-chest cardiac massage in providing relaxation-phase and compression-phase pressure gradients during cardiac arrest in patients failing current ACLS protocols. During open-chest cardiac massage, all patients exceeded the minimum coronary perfusion pressure of 15 mm Hg, which is recommended to obtain a return of spontaneous circulation. Further outcome studies are needed to determine the timeliness and appropriate indications for open-chest cardiac massage.

[Ibuprofen--successful in activated arthrosis. Results of a administration study]

Within the framework of an observational study carried out on a national basis and involving some 4,000 patients, a total of 1,156 patients with activated arthrosis were treated with oral ibuprofen and observed over a period of three weeks. It was found that, at a dose of 600 mg tid, ibuprofen led to significant remission rates in terms of the symptoms pain at rest, pain on movement, tenderness, restriction of movement, swelling, joint effusion, and morning stiffness. After the third week of treatment, these rates reached 90%. In the first week, rapid onset of action within the first 30 minutes was noted in about 50%, which increased in the third week to 65%. Since at the same time the tolerability of ibuprofen was also found to be good--4% side effects--it can be recommended also for long-term use in this indication.

Health care worker exposure to HIV-1 and HTLV I-II in critically ill, resuscitated emergency department patients

STUDY OBJECTIVE

Exposure to HIV-1 is of profound concern to health care workers. HTLV-I and HTLV-II, retroviruses with similar modes of transmission as HIV-1, also cause disease in human beings. Emergency department resuscitations are high-risk situations for such exposure. The purpose was to determine the seroprevalence of HIV-1 and HTLV I-II in patients undergoing ED resuscitations, the magnitude of health care worker exposure, and risk factors associated with infection.

DESIGN

Prospective identity-unlinked seroepidemiologic study.

SETTING

ED of a 950-bed private inner-city teaching hospital. Participants included 370 patients undergoing ED resuscitations.

MEASUREMENTS

Serum was tested for antibodies to HIV-1 and HTLV I-II. Questionnaires were completed by the physician in charge of the ED resuscitations.

RESULTS

Fifteen (4.1%) (95% confidence interval [CI], 2.1% to 6.1%) patients were HIV-1 seropositive, and seven (1.9%) (95% CI, 0.7% to 3.1%) were HTLV I-II positive. Eleven (5.6%) (95% CI, 2.4% to 8.8%) of 197 trauma patients and 11 (6.4%) (95% CI, 2.8% to 10.0%) of 173 medical patients were infected with one of these viruses. Health care workers had direct cutaneous contact with patient blood during 114 (31%) ED resuscitations and with infected patient blood during 11 (3%) ED resuscitations. An additional 11 ED resuscitations involved parenteral exposures, one to HIV-1-infected blood. No factors could be identified that would quickly and reliably predict infection.

CONCLUSION

Health care workers must protect themselves in such high-risk situations by strict compliance to mandatory universal precautions.

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)

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.

Esophageal involvement in secondary amyloidosis mimicking achalasia

Amyloidosis is usually considered as a cause of motor disorders of the esophagus, including achalasia. However, most patients with amyloid in the esophagus are AL-type amyloid. We report what we believe is the fourth case of secondary amyloidosis (AA-type) resulting from rheumatoid arthritis. Clinically and radiologically the picture was that of achalasia.

Prolonged hyperinsulinism and hypoglycemia. In an asphyxiated, small for gestation infant. Case management and literature review

The authors describe a term female, asphyxiated, small for gestational age (SGA) infant with documented hyperinsulinism and hypoglycemia occurring at approximately 45 hours of age. The hypoglycemia was refractory to a high rate glucose infusion and steroid administration but responded to diazoxide. The subsequent hospital course was complicated by right-sided heart failure and sepsis. With the onset of sepsis, a transient hyperglycemia was noted that required intermittent insulin therapy for 10 days. Hypoglycemia and hyperinsulinism reemerged and responded to diazoxide therapy. An attempt to discontinue diazoxide at age 6 months was aborted at 2 weeks when hyperinsulinism and hypoglycemia recurred. The infant required diazoxide for 7 more months, then she recovered without having any sequelae. The review of this uncommon hypoglycemia etiology in an SGA and asphyxiated infant and the merits of long-term diazoxide treatment are discussed.

All-trans retinoic acid and 13-cis-retinoic acid in the rat whole-embryo culture: abnormal development due to the all-trans isomer

9.5-day-old rat embryos were exposed to 3 micrograms 13-cis retinoic acid (13-cis-RA)/ml culture medium or 1 microgram all-trans retinoic acid (all-trans-RA)/ml culture medium for different time intervals of the culture period (test substance-exposure periods alternated with test substance-free periods). These studies were performed to confirm the hypothesis (Klug et al. 1989) that the effect of 13-cis-RA on embryonic development in vitro is predominantly caused by its isomerisation to all-trans-RA. A 12 h exposure of the rat embryos to 13-cis-RA during different periods of culture did not interfere with normal development. However, a 12 h exposure of the embryos to all-trans-RA in the first three quarters of the culture period significantly interfered with normal development and caused clear-cut and typical abnormalities. Embryonic exposure to 13-cis-RA, for periods of more than 12 h, caused severe interference with normal development and led to branchial effects very similar to those observed following to a 12 h exposure to all-trans-RA.

Prenatal toxicity of acyclovir in rats

Pregnant rats were treated during organogenesis with s.c. injections of acyclovir and the embryos were evaluated on day 11.5 of gestation (crown-rump length, somites, protein content, score, abnormalities, histological examination). After eight injections of 50 mg/kg body wt on days 9, 10, and 11 of pregnancy a reduction of the crown-rump length was noticed. After 100 mg/kg this effect was more pronounced. With two or three applications of this dose on day 10 specific embryonic abnormalities were visible: the shape of the head was abnormal, the width of the skull had decreased resembling a beak-like visceral cranium. With a single administration of 200 mg/kg on day 10 we found a similar but slightly more pronounced outcome. A drastic change of all variables was obtained after eight injections of 100 mg/kg on days 9, 10, and 11. Comparatively we measured maternal plasma concentrations of acyclovir 1 h after the administration of 50, 100 or 200 mg/kg body wt. After an injection of 50 mg/kg on days 9, 10, and 11 of gestation (three injections/day) the plasma levels ranged from 19.1 to 40.0 mg/l (1 mg/l = 4.44 microM). No cumulation was observed. In contrast, a cumulative effect was detected following a dose of 100 mg/kg. After the first injection of this dose a mean value (+/- SD) of 60.3 +/- 14.7 mg/l (n = 16) was obtained. In this case a third injection increased the mean plasma level to 124.6 +/- 16.6 mg/l (n = 5). Further injections, however, led to decreasing levels. One hour after administration of 200 mg/kg body wt acyclovir levels ranged from 120.0 to 163.9 mg/l. We conclude that acyclovir, at doses leading to plasma concentrations well above the therapeutic level in the dam, interferes with the embryonic development in the rat. Acyclovir induces typical gross structural abnormalities which have been first observed using a whole embryo culture system.

Pharmacokinetic aspects of drug effects in vitro: effects of serum protein binding on concentration and teratogenicity of valproic acid and 2-en-valproic acid in whole embryos in culture

Pharmacokinetic studies were performed in connection with culture experiments. Using the technique of cultivating whole rat embryos of the early postimplantation stage, we measured the concentration of valproic acid (VPA) and 2-en-VPA in the culture medium (free and protein-bound form) and in embryonic tissue. The following results were obtained: The concentrations of VPA and 2-en-VPA reached in the embryos were lower than corresponding total concentrations added to the culture medium, but exceeded the free concentrations in the medium. The concentrations of 2-en-VPA found in the embryo were lower than the comparable VPA total levels because of the more extensive protein binding of 2-en-VPA in the culture serum. The percentage of binding to serum proteins decreased with increasing total drug concentrations in the medium; the concentration of the free drug in the medium increased overproportionally with increasing total drug concentrations. Therefore, the free drug concentrations in the medium were not proportional to the dose of the drug dissolved in the medium (for a drug bound to plasma proteins). The concentrations of VPA and 2-en-VPA found in the embryos after incubation in vitro were not proportional to the drug concentrations dissolved in the medium. This result has to be taken into account when dose-response relationships are evaluated. VPA concentrations of 40 micrograms/g wet weight and above in the embryos clearly induced abnormal development in about 30% of the embryos, while 2-en-VPA concentrations as high as 200 micrograms/g embryo (wet weight) were inactive.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of acyclovir on mammalian embryonic development in culture

Acyclovir [9-(2-hydroxyethoxymethyl)guanine] interfered with embryonic development in vitro when assessed with the "whole-embryo" culture technique. The "no-observed-effect level" was at 10 microM acyclovir; Minor impairment of embryonic development (retarded development of ear anlagen) was observed in vitro at 25 microM acyclovir in the culture medium. At high concentrations (100 or 200 microM) development of the ear anlagen was largely inhibited. At concentrations of 50 microM acyclovir or higher, additional disturbances of embryonic differentiation in vitro became obvious, resulting in gross structural abnormalities, especially of the brain (telencephalon); Histological examinations confirmed and extended these observations: at 100 microM acyclovir alterations of the neuroepithelium of the ventricles were pronounced, the telencephalon had developed poorly or was almost completely absent, and necroses were seen in the ear anlagen, the maxillary branch and within the somites; In a limb bud culture (mouse embryos, starting with day 11 of gestation) acyclovir interfered with the differentiation of cartilaginous bone anlagen at concentrations of 200 microM and more in the culture medium. A concentration of 100 microM induced no significant effect. Thus, this organ culture system is less sensitive to the action of acyclovir when compared with whole-embryo culture; Contrary to the results achieved with acyclovir, physiological nucleosides (2'-deoxyguanosine and 2'-deoxyadenosine) did not interfere with embryonic development in vitro even at the highest concentration tested (500 microM).

Modification and standardization of the culture of early postimplantation embryos for toxicological studies

The method of culturing "whole" rat embryos (days 9.5-11.5 of gestation, i.e. at the early stage of organogenesis) as modified and standardized in our laboratory is presented; We have succeeded in using bovine serum as culture medium instead of rat serum as recommended in the original procedure. Experimental conditions are described for obtaining reproducible results; An improved scoring system was developed which, in connection with a computerized documentation, greatly facilitates the evaluation of the data.