Vitamin D Maintains Growth and Bone Mineral Density against a Background of Severe Vitamin A Deficiency and Moderate Toxicity in a Swine Model.

Excessive vitamin A (VA) negatively impacts bone. Interactions between VA and vitamin D (VD) in bone health are not well-understood. This study used a traditional two-by-two factorial design. Pigs were weaned and randomized to four treatments (n = 13/group): -A-D, -A+D, +A-D, and +A+D for 3 and 5 wk. Serum, liver, kidney, adrenal glands, spleen, and lung were analyzed by ultra-performance LC. Growth was evaluated by weight measured weekly and BMD by DXA. Weights were higher in -A+D (18.1 ± 1.0 kg) and +A+D (18.2 ± 2.3 kg) at 5 wk than in -A-D (15.5 ± 2.1 kg) and +A-D (15.8 ± 1.5 kg). Serum retinol concentrations were 0.25 ± 0.023, 0.22 ± 0.10, 0.77 ± 0.12, and 0.84 ± 0.28 µmol/L; and liver VA concentrations were 0.016 ± 0.015, 0.0065 ± 0.0035, 2.97 ± 0.43, 3.05 ± 0.68 µmol/g in -A-D, -A+D, +A-D, and +A+D, respectively. Serum 25(OH)D3 concentrations were 1.5 ± 1.11, 1.8 ± 0.43, 27.7 ± 8.91, and 23.9 ± 6.67 ng/mL in -A-D, +A-D, -A+D, +A+D, respectively, indicating a deficiency in -D and adequacy in +D. BMD was highest in +D (p < 0.001). VA and the interaction had no effect on BMD. Dietary VD influenced weight gain, BMD, and health despite VA status.

Seroprevalence of Q fever (Coxiella burnetii) in sheep in the Kwahu West municipality, Eastern Region, Ghana.

Query fever, also known as Q fever, is a zoonotic disease caused by Coxiella burnetii. It is a cause of abortion in livestock and presents as a febrile illness in humans. A correlation between the incidence of the disease in humans and abortion in goats and sheep farms has been reported in countries such as the Netherlands and Australia. In Ghana, the occurrence of Q fever in both livestock and humans has not been fully explored. This study sought to determine the seroprevalence of Q fever in livestock in Nkawkaw, in the Eastern Region of Ghana. Sera obtained from 92 sheep from 12 farms were tested using the indirect multi-species ELISA for the detection of anti-Coxiella burnetii antibodies. Animal demographics, farms' proximity to human settlement and history of abortion in relation to the Q fever status were assessed. The overall prevalence of Q fever was 13.0 % [95 % CI 6.9-21.6] (12/92). Both sexes were equally affected, with a sex-specific prevalence of 13.0 % each. The farm-specific prevalence was 50 %. Abortions were reported on eight (8) of the 12 farms, and all farms were located less than 200 m from human habitation. Only proximity of farm to human settlement showed statistical significance. Q fever is prevalent in Nkawkaw and requires the attention of both animal and health authorities, using the One- Health approach to nip any future epidemics in its bud.

Evidence-based screening, clinical care and health education recommendations for Alaska Native peoples with prediabetes living in southcentral Alaska: findings from the Alaska EARTH follow-up study.

Pre-diabetes (pre-DM) is a strong predictor of diabetes (DM) over time. This study investigated how much of the recent increase in pre-DM identified among Alaska Native (AN) peoples living in urban southcentral Alaska may be due to changes in diagnostic methods. We used clinical and demographic data collected at baseline between 2004 and 2006 and at follow-up collected between 2015 and 2017 from the urban southcentral Alaska Education and Research Towards Health (EARTH) cohort. We used descriptive statistics and logistic regression to explore differences in demographic and clinical variables among the identified pre-DM groups. Of 388 participants in the follow-up study, 243 had A1c levels indicating pre-DM with only 20 demonstrating pre-DM also by fasting blood glucose (FBG). Current smoking was the sole predictor for pre-DM by A1c alone while abdominal obesity and elevated FBG-predicted pre-DM by A1c+FBG. No participants had an elevated FBG without an A1c elevation. A substantial portion of the rise in pre-DM found among urban southcentral AN peoples in the EARTH follow-up study was due to the addition of A1c testing. Pre-DM by A1c alone should be used to motivate behavioural changes that address modifiable risk factors, including smoking cessation, physical activity and weight management.

Repeated High-Dose Vitamin A Supplements, Standard of Care for Treating Xerophthalmia, Leads to Hypervitaminosis A in Piglets.

BACKGROUND: Vitamin A (VA) deficiency and excess negatively affect development, growth, and bone health. The World Health Organization's standard of care for xerophthalmia due to VA deficiency, is 3 high-dose VA supplements of 50,000-200,000 IU, based on age, which may cause hypervitaminosis A in some individuals. OBJECTIVES: This study measured VA status following 3 VA doses in 2 piglet studies. METHODS: In Study 1, 5 groups of piglets (n = 10/group) were weaned 10 d postbirth to VA-free feed and orally administered 0; 25,000; 50,000; 100,000; or 200,000 IU VA ester on days 0, 1, and 7. On days 14 and 15, the piglets underwent the modified relative dose-response (MRDR) test for VA deficiency, and were killed. Tissues were collected for high-pressure liquid chromatography analysis. Study 2 used the same design in 3 groups (n = 13/group) weaned at 16 d and administered 0; 25,000; and 200,000 IU doses. RESULTS: In Study 1 (final weight: 3.6 ± 0.7 kg), liver VA concentration was hypervitaminotic in 40%, 90%, and 100% of 50,000; 100,000; and 200,000 IU groups, respectively. The 25,000 IU group was 100% adequate, and the placebo group was 40% deficient. In Study 2 (final weight: 8.7 ± 0.8 kg), where 200,000 IU could be prescribed to infants with a similar body weight, 31% of the piglets were hypervitaminotic, the 25,000 IU group was 100% VA adequate, and the placebo group was 100% deficient. The MRDR test measured deficiency in 50% and 70% of the placebo group in each study but had 3 false positives among hypervitaminotic piglets in Study 1. CONCLUSIONS: Repeated high-dose VA may cause hypervitaminosis, indicating dose sizes may need reduction. The MRDR resulted in false positives in a hypervitaminotic state during malnutrition and should be paired with serum retinyl ester evaluation to enhance VA status assessment in populations with overlapping interventions.

Unwinding And The Medicaid Undercount: Millions Enrolled In Medicaid During The Pandemic Thought They Were Uninsured.

Policy responses to the March 31, 2023, expiration of the Medicaid continuous coverage provision need to consider the difference between self-reported Medicaid participation on government surveys and administrative records of Medicaid enrollment. The difference between the two is known as the "Medicaid undercount." The size of the undercount increased substantially after the continuous coverage provision took effect in March 2020. Using longitudinal data from the Current Population Survey, we examined this change. We found that assuming that all beneficiaries who ever reported enrolling in Medicaid during the COVID-19 pandemic public health emergency remained enrolled through 2022 (as required by the continuous coverage provision) eliminated the worsening of the undercount. We estimated that nearly half of the 5.9 million people who we projected were likely to become uninsured after the provision expired, or "unwound," already reported that they were uninsured in the 2022 Current Population Survey. This finding suggests that the impact of ending the continuous coverage provision on the estimated uninsurance rate, based on self-reported survey data, may have been smaller than anticipated. It also means that efforts to address Medicaid unwinding should include people who likely remain eligible for Medicaid but believe that they are already uninsured.

Diagnostic utility of selected faecal biochemical parameters in the determination of acute diarrhoea and associated defecation stooling characteristics in dogs: An observational study.

Diarrhoea, which is a clinical manifestation of various illnesses, is frequently observed in dogs. Regrettably, many dog owners find it difficult to provide comprehensive case histories, primarily because of limited interaction with their canine companions. This study aimed to evaluate the potential of faecal biochemical analytes in detecting and characterizing acute diarrhoea in dogs. Sixty-two domestic dogs were selected using the proportionate stratified sample technique. A structured questionnaire was used to collect demographic and clinical data. Faecal stool specimens from the dogs were obtained using the colon flush technique. The specimens were taken through biochemical analysis to determine urea, creatinine, total bilirubin, total cholesterol, triglycerides, gamma-glutamyl transferase and uric acid levels. Results showed a significant association between the diarrhoea status of the participants and their age, weight, breed, body size, source of last diet, period of inappetence, and other gastrointestinal signs (p < 0.050, respectively). Dogs that had not eaten in at least three days were five times more likely (p < 0.05) to have diarrhoea. Furthermore, miniature breeds were about six times more likely to develop diarrhoea (p < 0.05). Of the seven selected biochemical parameters, total faecal cholesterol was the most predictive index in diagnosing acute diarrhoea in dogs, with a likelihood ratio of 6.5, and it was the most accurate in predicting defecation stooling frequency and texture. In summary, in situations of inadequate case histories, measuring total faecal cholesterol could assist veterinarians in detecting diarrhoea and predicting its faecal stooling texture and frequency in dogs.

Doctoral graduates' attitudes toward scholarly work and Institutional Review Board and Quality Improvement Committee education and submission processes: A pilot study.

BACKGROUND: Educators are challenged to find better ways to prepare doctoral nursing students to conduct scholarly work involving human subjects. PURPOSE: To better understand doctoral nursing students' attitudes toward programmatic scholarly work and Institutional Review Board (IRB)/Quality Improvement Committee (QIC) education and submission processes. METHODS: Recent Doctor of Nursing Practice (DNP) and Philosophy of Nursing (PhD) graduates were recruited using convenience sampling techniques to participate in this cross-sectional, descriptive, mixed-methods pilot study. Data were collected using two researcher-developed instruments. DISCUSSION: Nineteen doctoral nursing students participated in this study. Students most often used a quantitative approach with health care providers to complete their scholarly work requirements. Both PhD and DNP participants were overall satisfied with the IRB/QIC content in the curricula and the submission process. Four themes were identified: (a) Efficiency, (b) Collaboration, (c) Faculty Mentorship, and (d) Areas for Improvement. CONCLUSION: Findings from this pilot study may be used to enhance IRB/QIC processes through revision of administrative processes and student education.

Major Traffic Safety Reform and Road Traffic Injuries Among Low-Income New York Residents, 2009-2021.

Objectives. To evaluate the effects of a comprehensive traffic safety policy-New York City's (NYC's) 2014 Vision Zero-on the health of Medicaid enrollees. Methods. We conducted difference-in-differences analyses using individual-level New York Medicaid data to measure traffic injuries and expenditures from 2009 to 2021, comparing NYC to surrounding counties without traffic reforms (n = 65 585 568 person-years). Results. After Vision Zero, injury rates among NYC Medicaid enrollees diverged from those of surrounding counties, with a net impact of 77.5 fewer injuries per 100 000 person-years annually (95% confidence interval = -97.4, -57.6). We observed marked reductions in severe injuries (brain injury, hospitalizations) and savings of $90.8 million in Medicaid expenditures over the first 5 years. Effects were largest among Black residents. Impacts were reversed during the COVID-19 period. Conclusions. Vision Zero resulted in substantial protection for socioeconomically disadvantaged populations known to face heightened risk of injury, but the policy's effectiveness decreased during the pandemic period. Public Health Implications. Many cities have recently launched Vision Zero policies and others plan to do so. This research adds to the evidence on how and in what circumstances comprehensive traffic policies protect public health. (Am J Public Health. 2024;114(6):633-641. https://doi.org/10.2105/AJPH.2024.307617).

Blood flow restriction training does not negatively alter the mechanical strength or histomorphology of uninjured equine superficial digital flexor tendons.

BACKGROUND: Low load exercise training with blood flow restriction (BFR) has become increasingly used by human physical therapists to prescribe controlled exercise following orthopaedic injury; its effects on the equine superficial digital flexor tendon (SDFT), however, are unknown. OBJECTIVE: To investigate outcomes of pressure specific BFR walking exercise on uninjured equine SDFT biomechanics and histomorphology. STUDY DESIGN: Controlled in vivo experiment. METHODS: Four forelimbs of four horses were exposed to 40 BFR-walk sessions (10-min interval walking) on a treadmill over a 56-day study period with their contralateral forelimbs serving as untreated controls. Similarly, four forelimbs of four control horses were exposed to 40 sham cuff walk sessions. On study Day 56, all horses (n = 8) were humanely euthanised and forelimb SDFTs underwent non-destructive biomechanical testing and corresponding histomorphological analysis. Significance in biomechanical parameters between treatment groups was analysed using a mixed-effects ANOVA with Tukey's post-hoc tests. RESULTS: Statistically significant differences in SDFT stiffness for both first (p = 0.02) and last cycles (p = 0.03) were appreciated within the BFR treated group only, with BFR exposed forelimbs being significantly stiffer than the contralateral unexposed forelimbs. When normalised to cross-sectional area, no significant differences were appreciated among treatment groups in elastic modulus for the first (p = 0.5) or last cycles (p = 0.4). No histological differences were appreciated among treatment groups according to Bonar, Movin, or musculotendinous junction evaluation criteria. MAIN LIMITATIONS: Short-term comparisons were performed in a small sample population without correlation to performance outcome measures. Optimal occlusion percentages and walk protocols remain unknown. CONCLUSIONS: This study demonstrated no negative impact of BFR on mechanical strength of the equine SDFT; however, evidence suggests that BFR results in increased tendon stiffness based on biomechanical testing and subsequent calculations. No consistent detrimental histomorphological changes were seen.

CONTEXTO: Exercício de baixa carga com restrição do fluxo sanguíneo (RFS) tem sido cada vez mais utilizado por fisioterapeutas humanos para tratar lesões ortopédicas. Porém, seus efeitos no tendão flexor digital superficial (TFDS) de equinos não é conhecida. OBJETIVOS: O objetivo deste estudo foi investigar o efeito de específicas pressões com RFS durante o passo em cavalos sem lesão no TFDS, por meio de histologia e análise biomecânica. DELINEAMENTO DO ESTUDO: Estudo controlado. MÉTODOS: Quatro membros torácicos de quatro cavalos foram expostos a 40 sessões de RFS durante o passo (10 minutos de caminhada intervalada), ao longo de 56 dias. O membro contralateral foi utilizado como controle. Da mesma forma, quatro membros de quatro cavalos controle foram expostos a 40 sessões simuladas de caminhada com torniquete. No dia 56, todos os cavalos (n = 8) foram eutanasiados, e os TFDS foram submetidos a testes biomecânicos não destrutivos e análise histológica. A significância dos parâmetros biomecânicos entre tratamentos foi analisada utilizando ANOVA de efeitos mistos, seguida pelo teste de Tukey. RESULTADOS: A rigidez do TFDS foi estatisticamente diferente nos primeiros (p = 0.02) e últimos (p = 0.03) ciclos no grupo submetido à RFS, sendo os membros tratados significativamente mais rígidos do que os membros contralaterais não expostos ao tratamento. Quando normalizado para a área transversal, não foi observada diferença significativa entre os grupos de tratamento no módulo de elasticidade para os primeiros (p = 0.5) e últimos (p = 0.4) ciclos. Não foram identificadas diferenças histológicas nos diferentes tipos de tratamento, de acordo com os critérios de avaliação Bonar, Movin e de junção musculo­tendínea. PRINCIPAIS LIMITAÇÕES: Comparações de curto prazo foram realizadas em uma amostra pequena da população, sem correlação com medidas de resultados de desempenho. As porcentagens ideais de oclusão e os protocolos de caminhada permanecem desconhecidos. CONCLUSÕES: Este estudo não demonstrou impacto negativo do RFS na resistência mecânica do TFDS equino; no entanto, as evidências sugerem que a RFS resulta em aumento da rigidez do tendão com base em testes biomecânicos e cálculos subsequentes. Nenhuma alteração histológica prejudicial consistente foi observada.

Differentiation and characterization of healthy versus pathological tau using chemical exchange saturation transfer.

Neurofibrillary tangles of tau constitute one of the key biological hallmarks of Alzheimer's disease. Currently, the assessment of regional tau accumulation requires intravenous administration of radioactive tracers for PET imaging. A noninvasive MRI-based solution would have significant clinical implications. Herein, we utilized an MRI technique known as chemical exchange saturation transfer (CEST) to determine the imaging signature of tau in both its monomeric and pathologic fibrillated conformations. Three sets of purified recombinant full-length (4R) tau protein were prepared for collection of CEST spectra using a 9.4 T NMR spectrometer at varying temperatures (25, 37, and 42 °C) and RF intensities (0.7, 1.0, 1.5, and 2.2 µT). Monomeric and fibrillated tau were readily distinguished based on their Z-spectrum profiles. Fibrillated tau demonstrated a less prominent peak at 3.5 ppm with additional peaks near 0.5 and 1.5 ppm. No significant differences were identified between fibrillated tau prepared using heparin versus seed-competent tau. In conclusion, monomeric and fibrillated tau can be readily detected and distinguished based on their CEST-derived Z-spectra, pointing to the potential utility of CEST-MRI as a noninvasive biomarker of regional pathologic tau accumulation in the brain. Further testing and validation in vitro and in vivo will be necessary before this can be applied clinically.

Cancer patients with clonal hematopoiesis die from primary malignancy or comorbidities despite higher rates of transformation to myeloid neoplasms.

BACKGROUND: The occurrence of somatic mutations in patients with no evidence of hematological disorders is called clonal hematopoiesis (CH). CH, whose subtypes include CH of indeterminate potential and clonal cytopenia of undetermined significance, has been associated with both hematologic cancers and systemic comorbidities. However, CH's effect on patients, especially those with concomitant malignancies, is not fully understood. METHODS: We performed a retrospective evaluation of all patients with CH at a tertiary cancer center. Patient characteristics, mutational data, and outcomes were collected and analyzed. RESULTS: Of 78 individuals included, 59 (76%) had a history of cancer and 60 (77%) had moderate to severe comorbidity burdens. DNMT3A, TET2, TP53, and ASXL1 were the most common mutations. For the entire cohort, the 2-year overall survival rate was 79% (95% CI: 70, 90), while the median survival was not reached. Of 20 observed deaths, most were related to primary malignancies (n = 7, 35%), comorbidities (n = 4, 20%), or myeloid neoplasms (n = 4, 20%). Twelve patients (15%) experienced transformation to a myeloid neoplasm. According to the clonal hematopoiesis risk score, the 3-year transformation rate was 0% in low-risk, 15% in intermediate-risk (p = 0.098), and 28% in high-risk (p = 0.05) patients. By multivariate analysis, transformation was associated with variant allele frequency ≥0.2 and hemoglobin <10 g/dL. CONCLUSIONS: In a population including mostly cancer patients, CH was associated with comorbidities and myeloid transformation in patients with higher mutational burdens and anemia. Nevertheless, such patients were less likely to die of their myeloid neoplasm than of primary malignancy or comorbidities.

Prelicensure Nursing Students' Attitudes Toward Patients With Cancer Revisited.

Recruiting graduate nurses into oncology practice postgraduation continues to be challenging. Graduate nurses tend to prefer clinical settings that they consider high-tech or challenging, with oncology ranking low. In additio.

Imaging a putative marker of brain cortisol regulation in alcohol use disorder.

Background: Stress is a potent activator of the hypothalamic-pituitary-adrenal (HPA) axis, initiating the release of glucocorticoid hormones, such as cortisol. Alcohol consumption can lead to HPA axis dysfunction, including altered cortisol levels. Until recently, research has only been able to examine peripheral cortisol associated with alcohol use disorder (AUD) in humans. We used positron emission tomography (PET) brain imaging with the radiotracer [18F]AS2471907 to measure 11ß-hydroxysteroid dehydrogenase type 1 (11ß-HSD1), a cortisol-regenerating enzyme, in people with AUD compared to healthy controls. Methods: We imaged 9 individuals with moderate to severe AUD (5 men, 4 women; mean age = 38 years) and 12 healthy controls (8 men, 4 women; mean age = 29 years). Participants received 93.5 ± 15.6 MBq of the 11ß-HSD1 inhibitor radiotracer [18F]AS2471907 as a bolus injection and were imaged for 150-180 min on the High-Resolution Research Tomograph. 11ß-HSD1 availability was quantified by [18F]AS2471907 volume of distribution (VT; mL/cm3). A priori regions of interest included amygdala, anterior cingulate cortex (ACC), hippocampus, ventromedial PFC (vmPFC) and caudate. Results: Individuals with AUD consumed 52.4 drinks/week with 5.8 drinking days/week. Healthy controls consumed 2.8 drinks/week with 1.3 drinking days/week. Preliminary findings suggest that [18F]AS2471907 VT was higher in amygdala, ACC, hippocampus, vmPFC, and caudate of those with AUD compared to healthy controls (p < 0.05). In AUD, vmPFC [18F]AS2471907 VT was associated with drinks per week (r = 0.81, p = 0.01) and quantity per drinking episode (r = 0.75, p = 0.02). Conclusions: This is the first in vivo examination of 11ß-HSD1 availability in individuals with AUD. Our data suggest higher brain availability of the cortisol-regenerating enzyme 11ß-HSD1 in people with AUD (vs. controls), and that higher vmPFC 11ß-HSD1 availability is related to greater alcohol consumption. Thus, in addition to the literature suggesting that people with AUD have elevated peripheral cortisol, our findings suggest there may also be heightened central HPA activity. These findings set the foundation for future hypotheses on mechanisms related to HPA axis function in this population.

Enhancing r1 Relaxivity in GdDOTA-Monoamide Complexes through Polar Group-Mediated Ordering of Second-Sphere Water Molecules.

This study was designed to test whether the single appended phosphonate group in GdDOTA-1AmP is sufficient for catalyzing the exchange of proton from the single inner-sphere water-exchanging molecule. Unlike the other phosphonate derivatives in this series, GdDOTA-1AmP showed a surprisingly smooth increase in r1 relaxivity from 3.0 to 6.3 mM-1 s-1 at 20 MHz as the pH was lowered from 9 to 2.5. In comparison to the bis-, tris-, and tetrakis-phosphonate analogues, which all show a biphasic dependence of r1 with changes in pH, the unique r1 versus pH characteristics of GdDOTA-1AmP are shown to closely parallel deprotonation of the single appended phosphonate group. Although the tissue biodistribution and clearance rates of GdDOTA-1AmP are more favorable than the other more highly charged phosphonate derivatives, the pH dependency of r1 is substantially reduced at magnetic fields typically used for small animal imaging (7 and 9.4T), so the attractiveness of this new molecule for quantitative imaging of tissue pH is diminished. However, this study provides some new insights into the feasibility of designing pH-responsive MRI contrast agents based upon fundamental acid-base prototropic mechanisms.

Housing-Sensitive Health Conditions Can Predict Poor-Quality Housing.

Improving housing quality may improve residents' health, but identifying buildings in poor repair is challenging. We developed a method to improve health-related building inspection targeting. Linking New York City Medicaid claims data to Landlord Watchlist data, we used machine learning to identify housing-sensitive health conditions correlated with a building's presence on the Watchlist. We identified twenty-three specific housing-sensitive health conditions in five broad categories consistent with the existing literature on housing and health. We used these results to generate a housing health index from building-level claims data that can be used to rank buildings by the likelihood that their poor quality is affecting residents' health. We found that buildings in the highest decile of the housing health index (controlling for building size, community district, and subsidization status) scored worse across a variety of housing quality indicators, validating our approach. We discuss how the housing health index could be used by local governments to target building inspections with a focus on improving health.

The role of neurosteroids in posttraumatic stress disorder and alcohol use disorder: A review of 10 years of clinical literature and treatment implications.

Rates of alcohol use disorder (AUD) are increasing in men and women and there are high rates of concurrent posttraumatic stress disorder (PTSD) and AUD. AUD and PTSD synergistically increase symptomatology and negatively affect treatment outcomes; however, there are very limited pharmacological treatments for PTSD/AUD. Neurosteroids have been implicated in the underlying neurobiological mechanisms of both PTSD and AUD and may be a target for treatment development. This review details the past ten years of research on pregnenolone, progesterone, allopregnanolone, pregnanolone, estradiol, testosterone and dehydroepiandrosterone/dehydroepiandrosterone-sulfate (DHEA/DHEA-S) in the context of PTSD and AUD, including examination of trauma/alcohol-related variables, such as stress-reactivity. Emerging evidence that exogenous pregnenolone, progesterone, and allopregnanolone may be promising, novel interventions is also discussed. Specific emphasis is placed on examining the application of sex as a biological variable in this body of literature, given that women are more susceptible to both PTSD diagnoses and stress-related alcohol consumption.

Sirenomelia: An anatomical assessment and genetic sex determination of two cases.

The etiology of sirenomelia is currently unknown. Data are limited in comparing external and internal abnormalities using modern imaging technologies and molecular genetic analysis. The purpose of the current study was designed to compare external and internal anatomical defects in two cases of sirenomelia and Potter's sequence. Considered rare, Potter's sequence is a fetal disorder with characteristic features of bilateral renal agenesis, obstructive uropathy, atypical facial appearance, and limb malformations. The internal and external malformations of two term fetuses with sirenomelia and Potter's sequence were compared using assessment of external features, radiography and MRI on internal structures, and molecular genetic studies on sex determination. Data reveal that both fetuses were male and manifested with an overlapping but distinct spectrum of abnormalities. Principal differences were noted in the development of the ears, brain, urogenital system, lower limbs, pelvis, and vertebral column. Defects of the axial mesoderm are likely to underlie the abnormalities seen in both fetuses. The first one, which had only caudal defects, was found to have a spectrum of abnormalities most similar to those associated with more severe forms of the small pelvic outlet syndrome, although the structure and orientation of the sacrum and iliae were different from previously reported cases. The other had both caudal and cranial defects, and was most similar to those described in the axial mesodermal dysplasia syndrome. Defects associated with sirenomelia can be evaluated with standard gross anatomy examination, radiology, MRI, and modified PCR techniques to determine anatomical abnormalities and the sex of preserved specimens, respectively. Evidence indicated that sirenomelia could be developed via various etiologies.