Radial head prosthesis after radial head and neck fractures - current literature and quality of evidence.

Due to the elbow joint's complex functional anatomy, the multifragmentary nature of many fractures and concomitant destabilizing associated injuries, dislocated fractures of the radial head and neck still present a serious challenge for the orthopedic surgeon. Thorough knowledge of the elbow's anatomy and biomechanics is essential to analyze and understand the injury and plan its treatment. The aim of a differentiated therapy approach is to restore the joint's anatomy and kinetics, stable and painless joint function, and to avoid or at least delay posttraumatic joint changes. The degree of dislocation, stability of fragments, size and number of fractured joint surfaces and associated bony and ligamentous injuries (and the instability they incur) must be addressed in the therapy regimen. There are various treatment options depending on the injury's classification, i.e. a Mason I fracture is treated conservatively, while more severe injuries may require osteosynthesis and endoprosthesis. There is a lack of clear therapy recommendations based on solid evidence regarding Mason classification types III-IV. In particular expert opinions diverge and study results are inconsistent. Especially the value of radial head arthroplasty is still hotly debated. Key words: radial head fracture, radial head prosthesis, radial neck fracture, Mason classification, radial head arthroplasty, elbow injury.

[Promoting the next generation - what can we improve?]. / Nachwuchsförderung - Was können wir besser machen.

The surgical faculties are threatened by a shortage of junior staff which also applies to orthopedics and traumatology. This article explains which concepts the Young Forum of the German Society of Orthopedics and Traumatology (DGOU) already actively promotes to get students enthusiastic about musculoskeletal surgery and what additional efforts are needed to ensure that the measures are successful.

Tibial shaft fractures - management and treatment options. A review of the current literature.

Treatment of tibial shaft fractures is still discussed controversial. In the present study current literature was reviewed with the objective to demonstrate current recommendations concerning tibial shaft fractures. Tibial shaft fractures are often caused by high-energy trauma with severe concomitant soft-tissue injuries. Solid bone union without hypertrophy, fast mobilization and full range of motion without further soft-tissue damages are the aims of the therapy. Non-displaced tibial shaft fractures in patients with good compliance can be treated conservatively. Deep venous thrombosis, compartment syndrome, soft tissue injury and chronic regional pain syndrome are the major risks of conservative treatment and need to be required. Operative treatment can be performed with several different implants. Intramedullary nailing with a huge biomechanical stability seems to be the implant of choice. Only rare indications for plate osteosynthesis can be found. The use of external fixation has declined even though external fixation is still the implant of choice in first line treatment of multiple trauma according to the damage control principles. Open fractures with precarious blood supply and weak soft tissue covering are vulnerable to complications and remain a challenge for every treating surgeon. Reconstruction of axis, length and rotation is essential for a good outcome. The choice of technique depends on fracture localization, type of fracture, history of concomitant disorders and soft tissue damage.

Platelet-rich plasma (PRP) as therapy for cartilage, tendon and muscle damage - German working group position statement.

PURPOSE: Platelet rich plasma (PRP) is widely used in orthopaedics, but is still heavily debated. Therefore, a survey among the German "Working Group for Clinical Tissue Regeneration" of the German Society of Orthopaedics and Traumatology was conducted to achieve a consensus about the current therapeutical potential of PRP. METHODS: A first survey (n = 65 experts, all orthopaedic/trauma surgeons) was conducted (n = 13 questions). Following, a second round (n = 40 experts) was conducted with 31 questions to achieve consensus in 5 categories: three most common indications, PRP application, future research areas. RESULTS: Therapeutic PRP application was regarded as useful (89%), possibly even more important in the future (90%). Most common indications were tendon pathologies (77%), osteoarthritis (OA) (68%), muscle injuries (57%) and cartilage damage (51%). Consensus was reached in 16/31 statements. The application of PRP for early knee OA (Kellgren-Lawrence grade II) was regarded as potentially useful, as well as for acute and chronic tendinopathies. For chronic lesions (cartilage, tendons), multiple injections (2-4) were seen preferable to singular injections. However, no sufficient data exists on the time interval between the injections. Standardization of PRP preparation, application, frequency, as well as determining the range of indication is strongly recommended. CONCLUSIONS: There is a need of further standardization of the PRP preparation methods, indication and application protocols for knee OA and other indications, which must be further evaluated in basic science studies and randomized controlled clinical trials. LEVEL OF EVIDENCE: Consensus of expert opinion, Level V.

Model cannons causing lethal traumata.

Model cannons are usually considered to be harmless toys; therefore no legal regulations are required. Nevertheless, suicidal intentions or playful experimentation can turn this toy into a lethal weapon. This paper describes two cases of misuse of model cannons, leading to severe injuries and consequently death: the first case was the result of a suicidal intention, where the cannon caused a bullet injury into the forehead with marked signs of close-firing and intensive brain damage. The second case was an accidental event, where the cannon induced an entry wound at the left chest wall with surrounding carbonization and a fatal rupture of the heart. Circumstances of the lethal situations and mechanisms of the cannons leading to fatal injuries including ballistic considerations are described. The report is supported by a thorough literature research.

Seropositivity to chlamydial lipopolysaccharide and Chlamydia pneumoniae, systemic inflammation and stable coronary artery disease: negative results of a case-control study.

OBJECTIVES: We investigated the association between seropositivity to chlamydial lipopolysaccharide (cLPS) or Chlamydia pneumoniae (CP) and angiographically documented coronary artery disease (CAD), and we examined the relationship between serostatus and markers of systemic inflammation. BACKGROUND: The potential contribution of CP to atherogenesis is still a matter of debate, and inflammation has been suggested to represent the link between infection and atherosclerotic disease. METHODS: Subjects age 40 to 68 years were recruited for this case-control study between October 1996 and November 1997: 312 patients with at least one coronary stenosis >50% and 479 age- and sex-matched blood donors without manifest CAD or history of angina. Antibodies against cLPS and CP, C-reactive protein (CRP), fibrinogen, plasma viscosity, leukocytes and neutrophils were determined. The study had a power of >80% to detect an odds ratio (OR) of 1.55 or above for the prevalence of immunoglobulin (IgG) antibodies against cLPS at a significance level of alpha = 0.05. RESULTS: Prevalence of IgG antibodies against cLPS was not different between cases and controls (61% vs. 62%; p = 0.7). The adjusted OR for the presence of CAD given positive IgG serostatus against cLPS was 0.9 (95% CI; 0.6 to 1.3). Similarly, no difference in the prevalence of IgG antibodies against CP was seen (88% vs. 87%; p = 0.6); the adjusted OR was 1.0 (95% CI; 0.6 to 1.6). Markers of inflammation did not show any statistically significant difference between cLPS seropositives and seronegatives. CONCLUSIONS: Our results indicate no strong association between CP and CAD, and increased systemic inflammation in patients with CAD does not seem to be due to seropositivity to cLPS or CP.

Current infection with Helicobacter pylori, but not seropositivity to Chlamydia pneumoniae or cytomegalovirus, is associated with an atherogenic, modified lipid profile.

Infectious agents may be involved in atherothrombogenesis. The potential pathogenic pathway, however, remains unclear. We investigated the association between various infectious agents and lipoproteins known to have an atherogenic effect. We recruited 470 healthy blood donors and 238 patients with angiographically proven coronary heart disease (CHD), aged 40 to 68 years. Seropositivity to Chlamydia pneumoniae (CP), chlamydial lipopolysaccharide, and cytomegalovirus (CMV) was determined; infection with Helicobacter pylori (HP) was assessed by using the [(13)C]urea breath test. In all subjects, total cholesterol, high density lipoprotein (HDL) cholesterol, lipoprotein(a), and various apolipoproteins (apos) were determined. In unadjusted analysis, mean HDL cholesterol concentration was significantly decreased in HP-positive healthy subjects (1.36 vs 1.44 mmol/L, P=0.006) compared with HP-negative subjects. The HDL cholesterol to total cholesterol ratio was significantly decreased in HP-positive (0.259 vs 0.276, P=0.01) and CP-seropositive (0.266 vs 0.280, P=0.04) healthy subjects compared with (sero)negatives. Mean apoAI levels were significantly lower in HP-positive healthy subjects (1.46 vs 1.51 g/L, P=0.03) and in CMV-positive healthy subjects (1.47 vs 1.52 g/L, P=0.01) compared with (sero)negative subjects. After multivariable adjustment by means of linear regression analysis, only the association between HP infection and decreased HDL cholesterol (P=0.002), decreased HDL cholesterol to total cholesterol ratio (P:=0.005), decreased apoAI (P=0.02), and increased apoB (P=0.02) persisted and remained significant. There was no independent association between other lipoproteins and serological markers of CP or CMV infection. Current infection with HP, but not seropositivity to CP or CMV, was associated with an atherogenic, modified lipid profile. These lipid alterations could explain, at least in part, the reported weak association between chronic HP infection and atherosclerotic diseases.

Helicobacter pylori heat shock protein 60 and risk of coronary heart disease: a case control study with focus on markers of systemic inflammation and lipids.

AIM: it has been suggested that antibodies against heat shock proteins seem to be involved in the pathogenesis of coronary heart disease (CHD). We conducted a case-control study to investigate whether antibodies against Helicobacter pylori heat shock protein 60 (hsp60) are associated with CHD, and focused specifically on markers of systemic inflammation and lipids. METHODS: all patients of German nationality aged 40-68 years who underwent coronary angiography at the University of Ulm between October 1996 and November 1997 and who had at least one coronary stenosis greater than 50% were included in the study. Controls were sampled from voluntary blood donors and were matched for sex and age. H. pylori hsp60 was assessed by Western blot (H. pylori Westernblot, AID Co., Strassberg, Germany). In addition, C-reactive protein, fibrinogen, plasma viscosity, leukocytes, HDL-cholesterol and Lp(a) were determined. RESULTS: overall, 312 patients and 479 controls were enrolled in the study (response in patients 78%, in controls 84%). Whereas 25.0 and 22.4% of the cases showed a hsp60 extinction of 100 or 20-99% (according to the reference blot), respectively, only 21.3 and 14.8% of the controls did so (P=0.004). The age and sex adjusted odds ratio (OR) for CHD was 1.53 (95% confidence interval (CI) 1.14-2.06) given an extinction of 20-100% compared with an extinction of 0-19%. The OR for CHD decreased to 1.28 (95% CI 0.90-1.81) after further adjustment for other covariates. With exception of HDL-cholesterol (lowest in subjects with the highest hsp60 extinction) none of the investigated inflammatory markers was associated with the hsp60 distribution. CONCLUSION: a high H. pylori hsp60 extinction seems not to be an independent risk factor for CHD in this population.

Homocysteine and methylenetetrahydrofolate reductase genotype: association with risk of coronary heart disease and relation to inflammatory, hemostatic, and lipid parameters.

AIM: It has been suggested that homocysteine (tHcy) levels and methylenetetrahydrofolate reductase (MTHFR) genotype are primary risk factors for coronary heart disease (CHD). We performed a case-control study to investigate whether tHcy levels and MTHFR genotype (677 C-->T mutation and 1298 A-->C mutation) are associated with CHD under special consideration of the possibility for confounding. METHODS: German speaking patients aged 40-68 years who underwent coronary angiography at the University of Ulm between April 1996 and November 1997 and who had at least one coronary stenosis greater than 50% were included in the study. Controls were sampled from voluntary blood donors and were matched for sex and age. tHcy levels were measured by high performance liquid chromatography and MTHFR genotype by means of polymerase chain reaction. In addition, C-reactive protein, fibrinogen, plasma viscosity, leukocytes, HDL-cholesterol and Lp(a) were determined. RESULTS: Overall, 312 patients and 479 controls were enrolled in the study (response in patients 78%, in controls 84%). Mean tHcy value was 9.43 micromol/l in CHD patients and 8.91 micromol/l in controls (P=0.145). Prevalence of 677TT-polymorphism was 9.9% in patients and 10.4% in controls (P=0.295). Prevalence of 1298CC-polymorphism was 9.7% in patients and 13.8% in controls (P=0.346). There was a clear association of tHcy-values, but not of 677TT- or 1298CC-genotype with conventional CHD risk factors. After adjustment for these risk factors no increased risk for CHD could be associated with increased tHcy-values, with 677TT or 1298CC-genotype, or with their combination. Also no statistically significant relationships of these parameters to inflammatory, rheologic or hemostatic parameters or lipids were detectable. CONCLUSION: These results do not confirm an independent relationship of tHcy values and MTHFR genotype with risk of CHD in the population studied.

Helicobacter pylori and abdominal symptoms: a population-based study among preschool children in southern Germany.

OBJECTIVE: To determine the relation of Helicobacter pylori infection with gastrointestinal symptoms in a healthy population-based sample of children. DESIGN: Population-based cross-sectional study of preschool children. SETTING: Screening examination for school fitness by physicians of the Public Health Service in Ulm, a city with 100 000 inhabitants in southern Germany. PARTICIPANTS: One thousand two hundred one preschool children. MAIN OUTCOME MEASURES: Infection status was determined by 13C-urea breath test. Information on gastrointestinal symptoms was collected from children's parents by a standardized questionnaire and integrated into a symptom score. Results. Nine hundred forty-five children participated in the study (response rate, 79%). Overall, 127 children (13.4%) were infected. H pylori infection was not positively related to specific gastrointestinal symptomatology. Infected children had even fewer symptoms when compared with uninfected children. CONCLUSIONS: Our results indicate that H pylori infection in children is mostly asymptomatic and not associated with specific gastrointestinal symptoms.

Dynamics of Helicobacter pylori infection in early childhood in a high-risk group living in Germany: loss of infection higher than acquisition.

BACKGROUND: The dynamics of Helicobacter pylori infection in early childhood are not yet well understood. AIM: To conduct a prospective study in a population of children known to be at high risk of H. pylori infection to elucidate the incidence and loss of infection in childhood. METHODS: Asymptomatic Turkish children [aged 1 (n = 56 children), 2 (n = 55 children) and 4 years (n = 69 children)] at baseline, on whom participating paediatricians had performed routine health screening examinations between September 1997 and October 1998, were included in the study. A follow-up was performed about 1 year later. The infection status was defined by means of an antigen-based stool assay. RESULTS: In total, for 137 of 180 (76%) children, follow-up information was available. At baseline examination, the prevalence of infection in children with follow-up information was 27%[95% confidence interval (CI), 20-35%]. The incidence of H. pylori infection among previously uninfected children was 7% (95% CI, 3-14%) and the loss of infection among previously infected children was 35% (95% CI, 20-54%) during follow-up. CONCLUSIONS: This prospective cohort study in a high-risk group of children living in Germany showed that H. pylori colonization may often not persist at an early age. Furthermore, the use of penicillins and macrolides may be associated with the loss of infection at an early age.

History of antibiotic treatment and prevalence of H. pylori infection among children: results of a population-based study.

We investigated the association of commonly prescribed antibiotics with the prevalence of current Helicobacter pylori infection among children. All children who were screened in 1996 for school fitness by physicians of the Public Health Service in Ulm, a city in the south of Germany, were invited to participate in the study. Infection status was determined by 13C-urea breath test. In addition, the parents of the children were asked to fill out a standardized questionnaire. Nine hundred forty-five out of the 1201 eligible children participated in the study (response rate = 79%). The children were aged 5 to 8 years. Seventeen children who were receiving antibiotics at the day of the breath test were excluded from the analysis. Overall, for 683 children (73.6%) a prior usage of antibiotics was reported. Prevalence of H. pylori infection was significantly lower in children with reported antibiotic usage (odds ratio = 0.46; 95% CI, 0.27-0.76 after adjustment for confounders). Our results suggest that information on prior usage of antibiotics should always be considered in studies evaluating prevalence and risk factors of H. pylori infection in children.

Pets are not a risk factor for Helicobacter pylori infection in young children: results of a population-based study in Southern Germany.

BACKGROUND: Helicobacter pylori may have multiple routes of transmission. It is unclear, however, whether the agent is also zoonotic and therefore transmitted from an animal reservoir. AIMS: The aim of this population-based study was to assess the relationship of exposure to pets and H. pylori infection among children in a population-based sample in Ulm, a city in the South of Germany. SUBJECTS AND METHODS: All children of German nationality who were to attend first grade in the school year 1996/1997 were included in the study. The 13C-urea breath test was used to determine active infection status. In addition the parents filled out a questionnaire to provide information about pets in the household as well as living conditions and socioeconomic factors of the family. RESULTS: Of 927 eligible preschool children 685 (74%) participated in the study. Prevalence of infection was 6.3%. Infection with H. pylori was not positively associated with contact with pets in general (p = 0.720) or to a specific kind of animal in bivariate and multivariable analyses as evaluated by means of logistic regression. CONCLUSIONS: These results suggest that pets in the household are not a risk factor for H. pylori infection among children in this population.

Prevalence and determinants of Helicobacter pylori infection in preschool children: a population-based study from Germany.

BACKGROUND: Helicobacter pylori is among the most common infections in humans and has been recognized as major cause of various gastroduodenal diseases. There is limited knowledge, however, on the prevalence and determinants of this infection in children. We addressed these issues in a population-based cross-sectional study in Southern Germany. METHODS: Study subjects were all preschool children in Ulm, a city in the South of Germany, who were screened for school fitness by physicians of the public health service in 1996. Infection status was determined by 13C-urea breath test. In addition, the parents of the children were asked to fill out a standardized questionnaire. RESULTS: In total, 945 out of the 1201 eligible preschool children participated in the study (response rate = 79%). The children were aged 5-8 years. The majority were of German nationality (72.6%). Overall, 127 children (13.4%) were infected with H. pylori. Nationality, place of residence in the first year of life and duration of living in Germany were strongly associated with H. pylori infection status. The prevalence varied from 4.8% (95% confidence interval [CI]: 3.3-6.8%) in children with German nationality who were born in Germany or had lived in Germany since their first year of life to 66.7% (95% CI: 29.9-92.5%) in the children with Turkish nationality who came to Germany after the first year of life. CONCLUSION: Our results showed a large variation in prevalence of H. pylori infection in children living in the same geographical area according to nationality. They indicate an association between living conditions in early childhood and H. pylori infection and indicate that H. pylori associated morbidity may evolve very differently in population subgroups living in the same area.

Quantitation of Helicobacter pylori in dental plaque samples by competitive polymerase chain reaction.

AIM: To establish a competitive PCR (cPCR) assay for quantitation of H pylori organisms in dental plaque samples. METHODS: The cPCR co-amplified target H pylori DNA and a known amount of internal standard template in the same tube with the same primers directed to 0.86 kb DNA of H pylori. The internal standard was a synthesised DNA bearing the same primer recognition sites at two ends and a non-homologous core sequence as the target DNA fragment. Quantitation was based on determination of the relative, not absolute, amounts of the differently sized and [32P]-dCTP labelled products derived from H pylori DNA and the competitive internal standard after gel electrophoresis separation. RESULTS: A significant correlation between known amounts of H pylori added to dental plaque samples and the results of the cPCR was found, and a standard line was developed which allowed quantitation of H pylori in the plaque samples. cPCR was performed on supragingival plaque samples from 10 adult patients with H pylori infection in the stomach, and from five adults and six children without H pylori infection in the stomach. The ranges of H pylori numbers were 1-213 (median 25), 6-76 (10), and 4-94 (14) cells/mg of dental plaque in the three groups, respectively. CONCLUSIONS: cPCR is useful for quantitation of H pylori in supragingival dental plaque samples; however, the number of the organisms in dental plaque samples seems very low.

Characteristic distribution pattern of Helicobacter pylori in dental plaque and saliva detected with nested PCR.

The precise mode of transmission and the natural reservoir for Helicobacter pylori are unknown. PCR assays have proved to be highly sensitive and specific and are regarded as the method of choice for detecting H. pylori DNA in the oral cavity. The aim of this study was to investigate the prevalence and distribution of H. pylori in the oral cavity. Forty-two patients undergoing gastroscopy were investigated for the presence of H. pylori in dental plaque and saliva by nested PCR, and in the stomach by the 13C-urea breath test. Samples tested comprised dental plaque from molars, premolars and incisors and saliva. Two sets of primers homologous to the 860-bp fragment of H. pylori DNA, which have been shown previously to be highly sensitive and specific, were used for nested PCR. Eleven patients (26.2%) were infected with H. pylori in the stomach. H. pylori DNA was identified in dental plaque samples from 41 patients (97%) and in 23 saliva samples (55%). The prevalence in dental plaque from molars, premolars and incisors was 82%, 64% and 59%, with an odds ratio of 3.18, 1.24 and 1 (reference), respectively. In conclusion, H. pylori was present in the oral cavity of 97% of tested patients, with a characteristic distribution that was independent of the infection status of the stomach. Thus H. pylori may belong to the normal oral microflora.

Qualitative and semi-quantitative value of a modified 13C-urea breath test for identification of Helicobacter pylori infection.

OBJECTIVE: The 13C-urea breath test (13C-UBT) is the method of choice in evaluating the success of therapy for eradication of Helicobacter pylori infection. For reasons of cost efficiency and practicability, urea dose and measurement duration have been reduced and the DOB (delta over baseline) cutoff level with the highest predictive value determined. Further, the efficacy of the modified 13C-UBT as a semi-quantitative test method was evaluated by comparison with histologically determined bacterial infiltration. METHODS: In a prospective study, a modified 13C-UBT with reduced urea dose (75 mg) and shortened measurement duration (30 min) was administered to 145 patients. The DOB cutoff with the highest predictive value was determined using relative operating characteristic analysis. Reference methods included histology, bacterial culture and the rapid urease test. The DOB value was compared with the histologically determined grade of bacterial infiltration and the correlation evaluated using the Spearman ranking method. RESULTS: Reduction of the DOB cutoff level from 5.0 per thousand to 3.5 per thousand led to significant improvement in sensitivity (78.9% vs. 91.2%) and accuracy (88.6% vs. 90.2%) of the 13C-UBT. Only five of 57 infected patients were incorrectly reported as non-infected after modification of the DOB level. In two of three patients in whom histological findings were negative but the 13C-urease test positive, bacterial growth was observed at culture. The DOB level correlated significantly with histological grade of bacterial infection. CONCLUSION: The modified 13C-UBT proved to be a sensitive, practicable and cost-effective method for detecting H. pylori infection and permits a semi-quantitative estimation of bacterial infiltration.

Helicobacter pylori infection, intake of analgesics or anti-inflammatory medication, and personal factors in relation to dyspeptic symptoms in patients of a general practitioner.

BACKGROUND: Several studies have assessed the relationship between Helicobacter pylori infection and dyspeptic symptoms in highly selected patient populations and they have yielded inconsistent results. AIM: To investigate the relationship between current H. pylori infection, intake of analgesics or anti-inflammatory medication, and personal factors with dyspeptic symptoms in a large, unselected patient population of a general practitioner (GP). METHOD: Consecutive patients of a GP were invited to participate in a cross-sectional study regardless of the reason for their visit. Active infection with H. pylori was measured using the 13C-urea breath test (13C-UBT). A standardised questionnaire covering demographic, socioeconomic and lifestyle factors, and dyspeptic symptoms was completed by the patients. The number and severity of dyspeptic symptoms were quantified using a symptom score. RESULTS: Five hundred and one out of 531 eligible patients returned their questionnaires; a response rate of 94.4%. The prevalence of H. pylori infection, as indicated by a positive 13C-UBT, was 21.1% and was unrelated to dyspeptic symptoms. After adjustment for potential confounders by multiple logistic regression, a symptom score in the upper quartile of the symptom score distribution was significantly associated with female sex (odds ratio [OR] = 1.8, 95% confidence interval [CI] = 1.1 to 3.0) and intake of analgesics or anti-inflammatory drugs other than non-steroidal anti-inflammatory drugs (NSAIDs) (OR = 2.3, 95% CI = 1.1 to 4.7). Older age (60 to 79 years) was associated with fewer symptoms (OR = 0.4, 95% CI = 0.2 to 0.9) when compared with the youngest age group (15 to 39 years). CONCLUSION: Female sex, younger age, and intake of analgesics or anti-inflammatory drugs other than NSAIDs, but not H. pylori infection, were independently associated with dyspeptic symptoms in this population.

A whole-embryo culture system proposed to study mouse sexual determination.

Standard procedures to culture rodent embryos (2-4 somite explanted embryos and a 48-hr culture period), do not allow assessment of genital crest differentiation. Cultures of older embryos have to be used for this objective. The proposed method uses glass apparatus derived from those initially decribed by New (1967) and Cockroft (1973). Each apparatus allows the culture of six embryos in 80ml of a permanently gassed (95% O(2)) and circulating culture medium [Waymouth's medium-Hanks' balanced salt solution-rat serum (40:40:20, by vol.)]. In this system, 24 embryos (four groups of six) can be cultured under the same experimental conditions. In the mouse, the genital crest begins to develop on gestation day (GD) 9 and differentiation can be observed between GD12 and GD13 [GD0 = middle of the mating period (09.00-11.00 hr)]. GD12 mouse embryos were cultured for 30 hr. An in vitro /itin vivo comparison of survival rate, development and morphology was performed. Serial sections of cultured embryos were taken for microscopic examination. Survival rate proved to be 82% using this method. No delay in general development was observed. Histological examination demonstrated that gonadal determination in cultured embryos also paralleled differentiation in vivo. The results clearly demonstrate that a 30-hr culture period of GD12 mouse embryos enables the study of the murine sexual determination.

Cell proliferation, migration and CAM-dependent neurite outgrowth as developmental in vitro endpoints for screening teratogenic potential: Application to valproic acid and related analogues of varying potency.

The in vivo teratogenic potential of valproic acid (VPA) and related teratogenic and non-teratogenic analogues has been correlated with their effects on specific in vitro endpoints of cell proliferation, migration and CAM-dependent neurite outgrowth, as these events are common to crucial epochs of development. The (+/-)-2-n-propyl-4-pentynoic acid [(+/-)-4-yn-VPA] and S-2-n-propyl-4-pentynoic acid [S(-)-4-yn-VPA] analogues increased the incidence of neural tube defects in mouse embryos exposed to a single dose, whereas the E-2-n-propyl-2-pentenoic acid (E-2-en-VPA) analogue and R-2-n-propyl-4-pentynoic acid [R( + )-4-yn-VPA] enantiomer were without effect. VPA and related analogues tested exerted comparable G1 phase antiproliferative effects in C6 glioma and limb bud cells in a dose range of 0-3 mM; however, their relative potency did not correlate with in vivo teratogenicity. In contrast, VPA and all teratogenic analogues, at 3 mM, inhibited neuronal cell aggregation and limb bud chondrocyte differentiation in a manner that exhibited a reasonable correlation with their in vivo teratogenicity. The teratogenic S(-)-4-yn-VPA and non-teratogenic R( + )-4-yn-VPA enantiomers exhibited a differential inhibition of primary neurone outgrowth of neuntes stimulated by cell adhesion molecules [L1 and N-cadherin (NCAD)]. Half-maximal inhibition was observed at approximately 150 muM for the teratogenic S(-)-4-yn-VPA enantiomer, but not the non-teratogenic R( + )-4-yn-VPA form. These results suggest that in vitro perturbations of differentiation are likely to provide the greatest discriminatory power for in vivo teratogenicity.