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Discovery efforts leading to the identification of ervogastat (PF-06865571), a systemically acting diacylglycerol acyltransferase (DGAT2) inhibitor that has advanced into clinical trials for the treatment of non-alcoholic steatohepatitis (NASH) with liver fibrosis, are described herein. Ervogastat is a first-in-class DGAT2 inhibitor that addressed potential development risks of the prototype liver-targeted DGAT2 inhibitor PF-06427878. Key design elements that culminated in the discovery of ervogastat are (1) replacement of the metabolically labile motif with a 3,5-disubstituted pyridine system, which addressed potential safety risks arising from a cytochrome P450-mediated O -dearylation of PF-06427878 to a reactive quinone metabolite precursor, and (2) modifications of the amide group to a 3-THF group, guided by metabolite identification studies coupled with property-based drug design.

As per the ICH Q3A(R2) and Q3B(R2) regulatory guidelines, safety studies may be needed when an impurity in new drug substances or products is above the qualification threshold, and such qualification studies should be conducted in one nonclinical species for a duration of 14-90 days. However, the guidelines do not specify details about species selection, recommended study design, and the exact study duration that would support clinical use of a specific duration. This lack of guidance leads to ambiguity and sponsors have used various study designs to qualify impurities. In 2018, the European Medicines Agency provided a draft reflection paper encouraging the incorporation of 3Rs (Replacement, Reduction, and Refinement) principles for animal use into impurity qualification. As a response, the IQ DruSafe Impurity Working Group (WG) surveyed the IQ member companies to capture the current practices for impurity qualification, and evaluate study designs for a potential reduction in animal testing. This article summarizes the results and learnings from the survey. Additionally, the WG leveraged the survey learnings and provided harmonized study design considerations aimed towards achieving the study objectives, while supporting the 3Rs initiative in reducing the total number of animals used (up to 90%) for impurity qualification., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Small molecule DGAT2 inhibitors have shown promise for the treatment of metabolic diseases in preclinical models. Herein, we report the first toxicological evaluation of imidazopyridine-based DGAT2 inhibitors and show that the arteriopathy associated with imidazopyridine 1 can be mitigated with small structural modifications, and is thus not mechanism related.

The medicinal chemistry and preclinical biology of imidazopyridine-based inhibitors of diacylglycerol acyltransferase 2 (DGAT2) is described. A screening hit 1 with low lipophilic efficiency (LipE) was optimized through two key structural modifications: (1) identification of the pyrrolidine amide group for a significant LipE improvement, and (2) insertion of a sp(3)-hybridized carbon center in the core of the molecule for simultaneous improvement of N-glucuronidation metabolic liability and off-target pharmacology. The preclinical candidate 9 (PF-06424439) demonstrated excellent ADMET properties and decreased circulating and hepatic lipids when orally administered to dyslipidemic rodent models.

The present article summarizes Metabolites in Safety Testing (MIST) studies on a glucokinase activator, N,N-dimethyl-5-((2-methyl-6-((5-methylpyrazin-2-yl)carbamoyl)benzofuran-4-yl)oxy)pyrimidine-2-carboxamide (PF-04937319), which is under development for the treatment of type 2 diametes mellitus. Metabolic profiling in rat, dog, and human hepatocytes revealed that PF-04937319 is metabolized via oxidative (major) and hydrolytic pathways (minor). N-Demethylation to metabolite M1 [N-methyl-5-((2-methyl-6-((5-methylpyrazin-2-yl)carbamoyl)benzofuran-4-yl)oxy)pyrimidine-2-carboxamide] was the major metabolic fate of PF-04937319 in human (but not rat or dog) hepatocytes, and was catalyzed by CYP3A and CYP2C isoforms. Qualitative examination of circulating metabolites in humans at the 100- and 300-mg doses from a 14-day multiple dose study revealed unchanged parent drug and M1 as principal components. Because M1 accounted for 65% of the drug-related material at steady state, an authentic standard was synthesized and used for comparison of steady-state exposures in humans and the 3-month safety studies in rats and dogs at the no-observed-adverse-effect level. Although circulating levels of M1 were very low in beagle dogs and female rats, adequate coverage was obtained in terms of total maximal plasma concentration (∼7.7× and 1.8×) and area under the plasma concentration-time curve (AUC; 3.6× and 0.8× AUC) relative to the 100- and 300-mg doses, respectively, in male rats. Examination of primary pharmacology revealed M1 was less potent as a glucokinase activator than the parent drug (compound PF-04937319: EC50 = 0.17 μM; M1: EC50 = 4.69 μM). Furthermore, M1 did not inhibit major human P450 enzymes (IC50 > 30 μM), and was negative in the Salmonella Ames assay, with minimal off-target pharmacology, based on CEREP broad ligand profiling. Insights gained from this analysis should lead to a more efficient and focused development plan for fulfilling MIST requirements with PF-04937319., (Copyright © 2014 by The American Society for Pharmacology and Experimental Therapeutics.)

Glucokinase activators (GKAs) are being developed for the treatment of type 2 diabetes. The toxicity of 4 GKAs (PF-04279405, PF-04651887, piragliatin, and PF-04937319) was assessed in mice, rats, dogs, and/or monkeys. GKAs were administered for 2 to 8 weeks. Standard endpoints, glucose, and insulin were assessed. All compounds produced varying degrees of hypoglycemia in all species. Brain neuronal necrosis and/or peripheral neuropathy were observed with most compounds. These findings are consistent with literature reports linking hypoglycemia with nervous system effects. Arteriopathy, mainly of cardiac vessels, was observed at a low frequency in monkey and/or dog. Arteriopathy occurred only at doses that produced severe and prolonged periods of repeated hypoglycemia. Since this lesion occurred in multiple studies with structurally distinct GKAs, these results suggested arteriopathy was related to GKA pharmacology. The morphological characteristics of the arteriopathy were consistent with that produced by experimental catecholamine administration. We hypothesize that the prolonged periods of hypoglycemia resulted in increased local and/or systemic concentrations of catecholamines via a counterregulatory and/or stress-related mechanism. Alternatively, prolonged hypoglycemia may have resulted in endothelial dysfunction leading to arteriopathy. This risk can be managed in human patients in clinical studies by careful glucose monitoring and intervention to avoid prolonged episodes of hypoglycemia., (© 2014 by The Author(s).)

Peroxisome proliferator-activated receptors (PPARs) represent therapeutic targets for the management of type 2 diabetes mellitus and dyslipidemia. Rodent carcinogenicity studies have revealed a link between γ and dual γ/α PPAR agonist treatment and the increased incidence of subcutaneous (SC) liposarcomas/fibrosarcomas or hemangiosarcomas, but very little has been reported for potent and selective PPARα agonists. We present a mode of action framework for the development of SC mesenchymal tumors in rodents given PPAR agonists. (1) Tumor promotion results from pharmacologically mediated recruitment (proliferation and differentiation), thermogenesis and adipogenesis of stromovascular cells, and subsequent generation of oxidative free radicals. (2) Tumor initiation consists of chemotype-driven mitochondrial dysfunction causing uncontrolled oxidative stress and permanent DNA damage. Promotion is characterized by enhanced adipogenesis in the SC adipose tissue, where the baseline PPARγ expression and responsiveness to PPARγ ligands is the highest, and by thermogenesis through expression of the uncoupling protein 1 (UCP-1) and the PPARγ co-activator 1 α (PGC-1α), two factors more highly expressed in brown versus white adipose tissue. Initiation is supported by the demonstration of mitochondrial uncoupling and OXPHOS Complexes dysfunction (Complexes III, IV and V) by compounds associated with increased incidences of sarcomas (muraglitazar and troglitazone), but not others lacking malignant tumor effects (pioglitazone, rosiglitazone).

Weak peroxisome proliferator-activated receptor (PPAR) α agonists (fibrates) are used to treat dyslipidemia. This study compared the effects of the potent and selective PPARα agonist CP-778875 on peroxisomal β-oxidation and cardiac and/or skeletal muscle injury with those of the weak PPARα agonist fenofibrate. We hypothesized that these muscle effects are mediated through the PPARα receptor, leading to increased β-oxidation and consequent oxidative stress. CP-778875 (5 or 500 mg/kg) and fenofibrate (600 or 2,000→1,200 mg/kg, dose lowered because of intolerance) were administered to rats for six weeks. Standard end points, serum troponin I, heart and skeletal muscle β-oxidation of palmitoyl-CoA, and acyl co-oxidase (AOX) mRNA were assessed. Both compounds dose-dependently increased the incidence and/or severity of cardiomyocyte degeneration and necrosis, heart weight, troponin I, and skeletal muscle degeneration. Mean heart β-oxidation (3.4- to 5.1-fold control) and AOX mRNA (2.4- to 3.2-fold control) were increased with CP-778875 500 mg/kg and both doses of fenofibrate. β-Oxidation of skeletal muscle was not affected by either compound; however, a significant increase in AOX mRNA (1.6- to 2.1-fold control) was observed with CP-778875 500 mg/kg and both doses of fenofibrate. Taken together, these findings were consistent with PPARα agonism and support the link between increased cardiac and skeletal muscle β-oxidation and resultant muscle injury in the rat.

Compound 4 (PF-04971729) belongs to a new class of potent and selective sodium-dependent glucose cotransporter 2 inhibitors incorporating a unique dioxa-bicyclo[3.2.1]octane (bridged ketal) ring system. In this paper we present the design, synthesis, preclinical evaluation, and human dose predictions related to 4. This compound demonstrated robust urinary glucose excretion in rats and an excellent preclinical safety profile. It is currently in phase 2 clinical trials and is being evaluated for the treatment of type 2 diabetes.

Zoniporide, an inhibitor of the Na+-H+ exchanger-1, was administered by continuous intravenous infusion to rats and dogs for up to 1 month. In 1-month studies, histological and functional changes were observed in select portions of the peripheral nervous system; however, these findings were not detected in 2-week studies at similar or higher doses. In the 1-month rat study, there was dose-dependent, minimal, focal, or multifocal nerve fiber (axonal) degeneration in the spinal cord and/or sciatic nerve. In a follow-up rat study, findings included slowing of caudal nerve conduction velocity and axonal degeneration in the spinal cord (dorsal funiculus), dorsal roots, dorsal root ganglia (DRG), radial, sciatic, and tibial nerves. In the 1-month dog study, there was impairment of the patellar reflex and associated postural reaction changes, minimal to marked proximal nerve fiber degeneration in the DRG, and minimal nerve fiber degeneration in the dorsal roots and funiculi of the spinal cord. Minimal nerve fiber degeneration of equivocal significance was noted in various peripheral nerves. Taken together, these findings were consistent with a specific effect on peripheral sensory nerve fibers. These studies demonstrated that zoniporide produces clinical, electrophysiologic, and microscopic evidence of peripheral sensory axonopathy and establishes the importance of careful preclinical evaluation of neurological function.

New tert-butyl, picolyl and fluorinated analogues of capromorelin (3), a short-acting growth hormone secretagogue (GHS), were prepared as part of a program to identify long-acting GHSs that increase 24-h plasma IGF-1 levels. Compounds 4c and 4d (ACD LogD values >or=2.9) displayed extended plasma elimination half-lives in dogs, primarily due to high volumes of distribution, but showed weak GH secretagogue activities in rats (ED(50)s>10 mg/kg). A less lipophilic derivative 4 (ACD LogD=1.6) exhibited a shorter canine half-life, but stimulated GH secretion in two animal species. Repeat oral dosing of 4 in dogs for 29 days (6 mg/kg) resulted in a significant down-regulation of the post dose GH response and a 60 and 40% increase in IGF-1 levels relative to pre-dose levels at the 8- and 24-h post dose time points. Compound 4 (CP-464709-18) has been selected as a development candidate for the treatment of frailty.

Growth hormone secretagogues (GHSs) represent attractive therapeutic alternatives to recombinant growth hormone (GH), given their ability to amplify pulsatile hormone secretion in a relatively physiologic manner. CP-424,391 (391) is a novel, orally active pyrazolinone-piperidine [corrected] GHS. In rat pituitary cell cultures, 391 stimulated GH release with an EC50 = 3 nM. The addition of 391 to rat pituitary cells activated intracellular calcium signaling but did not elevate intracellular cyclic adenosine monophosphate (cAMP). 391 also modulated the effects of GH-releasing hormone and somatostatin on pituitary cell GH-release and intracellular signaling. In nonpituitary cell lines, the ability of 391 to stimulate intracellular signaling was dependent on the expression of recombinant human GHS receptor. Acute administration of 391 to anesthetized rats or to conscious dogs induced pulsatile release of G H in a dose-dependent manner. Plasma insulin-like growth factor-I (IGF-I) was elevated progressively over a 5-d course of daily oral dosing in dogs. Chronic oral administration of 391 augmented body weight gain in rats and dogs. Thus, the peptidomimetic GHS 391 has potential utility for the treatment of clinical conditions that could benefit from systemic augmentation of GH and IGF-I levels.

In this 2-year study, the suitability of the Hsd:Sprague-Dawley SD (SD) as a replacement for the Crl:CD BR (CD) rat was assessed by comparing survival rates, palpable mass incidence, body weights, food consumption, clinical laboratory parameters, and necropsy and histopathology observations. At week 104, survival rates in the CD and SD males were 29 and 49%, respectively. Corresponding survival rates in females were 44 and 63%. The total numbers of animals with palpable masses and animals with neoplasms were similar in the CD and SD rats; however, the total numbers of palpable masses and neoplasms were higher in the CD rats. The incidence of corneal lesions was higher in the SD rats, whereas the incidence of lenticular opacities was higher in the CD rats. Body weights, food and water consumption, and organ weights were significantly lower in the SD rats. In contrast, food intake per kilogram of body weight was slightly higher in the SD rats. Numerous differences in clinical laboratory parameters between the CD and SD rats were observed. Some of these were consistent with the increased prevalence of kidney disease and secondary sequelae in the SD rats. Taken together, the better survival, smaller size, and lower food consumption of the SD rat may make it a better model for chronic bioassays. However, the increased propensity for spontaneous renal disease may limit the utility of the SD rat for studying nephrotoxic compounds.

With the early generations of computed tomographic (CT) scanners, interpretation of abdominal and pelvic scans focused on the solid organs, hollow viscera, and retroperitoneum. Attention to blood vessels generally was given only to the aorta and inferior vena cava and their larger branches. The newer generations of scanners allow rapid acquisition of high-resolution images during the vascular phase of mechanical bolus injection of intravenous contrast material. Visualization of second-order vascular branches has thus become routine. Recent improvements in software allow real-time reconstruction of data in multiple planes, which enables demonstration of long segments of vessels within a single image. Approximately 7,000 abdominal and pelvic CT scans were reviewed with attention to vascular detail. Cases are presented that illustrate peripancreatic, perigastric, parietal, and hypogastric vessels; fetal remnants and structures that may be mistaken for vessels; and collateral pathways of both arterial and venous flow. With increasing use of helical CT scanning, smaller vessels can be identified with greater confidence. Knowledge of normal CT vascular anatomy facilitates understanding of collateral pathways when vessel engorgement is perceived.

Brain mitochondrial cytochrome oxidase and respiratory activities were compared after in vivo and in vitro exposure to cyanide. For the in vivo studies, mice were exposed to a non-lethal (4 mg kg-1) or lethal (20 mg kg-1) dose of KCN. From these mice, purified brain mitochondria were prepared and cytochrome oxidase and respiratory activities measured. Results of these experiments revealed greater inhibition of cytochrome oxidase activity following a lethal (20 mg kg-1) than a non-lethal (4 mg kg-1) KCN dose (57 and 45% inhibition, respectively). Respiration states 3 and 4 of brain mitochondria prepared from mice that received 4 mg kg-1 KCN were inhibited by 15 and 20%, respectively. In mice that received a lethal 20 mg kg-1 KCN dose, respiration states 3 and 4 were each inhibited by ca. 30% (P < 0.05). In vitro, mitochondrial cytochrome oxidase activity was inhibited in a concentration-dependent fashion at cyanide concentrations of 10(-6)-10(-2) M. A biphasic inhibition of ADP-stimulated (state 3) respiration was observed. Cyanide concentrations of 10(-6)-10(-4) M produced only a 25% inhibition of respiration state 3, whereas 10(-3) M produced 80% inhibition. Because this dramatic inhibition only occurred at cyanide concentrations that caused > 50% inhibition of mitochondrial cytochrome oxidase activity, these findings suggest that a large proportion of cytochrome oxidase activity may be functional reserve and that cyanide poisoning likely involves other mechanisms in addition to inhibition of cytochrome oxidase.

Two infants with the Hanhart syndrome, i.e. micrognathia, microglossia, terminal deficiency of all limbs and imperforate anus in one, were dissected and studied in detail. The interrelationships of the muscular and skeletal defects suggested that they were the result of incomplete rather than abnormal morphogenesis. We speculate that the oral and limb abnormalities resulted from deficient mesodermal proliferation caused by disturbances in the ectodermal-mesodermal interactions beginning about the 4th week of development. The imperforate anus may also relate to the proposed defect.

The brain findings at autopsy of an 18-year-old male with FG syndrome were megalencephaly, midline fusion of mammillary bodies, heterotopia of neuroglial tissue in the 7th and 8th nerves, and ependymal cell replacement by neuroglial tissue as well as a diffuse defect of neuronal cell migration evidenced from pachygyria of many gyri, dysgenesis of cerebral cortex, and heterotopia of neurons in the white matter of the centrum ovale. A cousin, studied at 20 weeks' gestational age, had gross turridolichocephaly with enlarged cranium and also multiple minor external and internal anomalies. An affected brother of this fetus died at 17 months of complications of a congenital heart defect and CNS dysfunction. X-linked inheritance of the FG syndrome is confirmed.

Dup (6p) patients have a peculiar facial appearance (frontal bossing, hypotelorism, hypoplastic midface), low birthweight, cardiovascular defects, small kidneys, and psychomotor retardation. We thought that a detailed anatomical dissection would more precisely define the syndrome, which has been developed from clinical evaluations and autopsy reports. Our patient, a female adolescent, died at 17 11/12 years and is the oldest patient with this syndrome to be described. The brain and skull showed the greatest number of abnormalities. The brain was smaller than normal and abnormally shaped. Many of the skull abnormalities, including shortened basisphenoid/basiocciput, reduced size of cranial fossae, and steep orbital roofs, may be attributed to the brain's shape. There were no olfactory bulbs, and only one rudimentary olfactory tract was present. Other findings were the following: a high interventricular septal defect and right ventricular hypertrophy, absence of uterus and vagina, hypoplastic ovaries, a common mesentery, two left extensor indicis bellies, bilateral absence of palmaris brevis and of peroneus tertius. Our results are compared with anomalies found in other aneuploidy syndromes. Variations in some organ systems may be similar to those whose presence Shapiro [1983] has attributed to amplified developmental instability. Relationships between the brain shape and size and skull abnormalities are also discussed. From 16 reported cases, a detailed autopsy report of the affected brother, and our anatomical findings, we suggest that this syndrome may also be characterized by arhinencephaly, common mesentery, absent uterus in the female, and growth retardation in those surviving the neonatal period.

A boy trisomic for the distal portion of 13q was dissected in detail and compared to 8 cases of complete trisomy 13 previously studied in our laboratory. The comparison shows that the partial trisomy 13q case did not correspond well to a muscle phenotype based on 6 variations common trisomy 13, but rather to a larger muscle phenotype that included variations less frequently observed in complete trisomy 13. Additional cases of partial trisomy 13 must be studied before these findings can be related to specific portions of chromosome 13.

Anti-cyanide action by sodium thiosulfate (ST) was enhanced by prior administration of chlorpromazine (CPZ). However, CPZ (alone) provided no protection against cyanide lethality. To investigate the possibility that CPZ enhances thiocyanate formation in ST-pretreated mice, the effects of CPZ on rhodanese activity and the time course of plasma thiocyanate concentrations were investigated. CPZ did not alter hepatic rhodanese kinetics nor did it enhance plasma thiocyanate concentrations in ST-pretreated mice. The effect of CPZ and ST on the time course of cytochrome oxidase inhibition and recovery, in vivo, was also investigated. At 4 mg KCN/kg, maximal inhibition of brain (40%) and heart (60%) cytochrome oxidase occurred 10 to 20 min post-challenge in control and CPZ-pretreated mice, while no inhibition occurred in ST- and CPZ/ST-pretreated mice. Twenty milligrams KCN/kg caused 100% lethality in control and CPZ-pretreated mice and 6/25 and 4/20 deaths were observed in ST- and CPZ/ST-pretreated mice, respectively. No significant inhibition of brain, heart, and liver cytochrome oxidase activities was observed in surviving ST- and CPZ/ST-pretreated mice challenged with 20 mg KCN/kg. Control and CPZ-pretreated mice died within 5 min of KCN challenge and had almost the same degree of inhibition of brain (35 and 29%, respectively) and heart (60 and 55%, respectively) cytochrome oxidase as did similarly pretreated mice 5 min after challenge with a nonlethal cyanide dose (4 mg/kg). Our results suggest that CPZ does not enhance the formation of thiocyanate in ST-pretreated mice. In addition, the similar degree of cytochrome oxidase inhibition noted after both lethal and nonlethal KCN treatments raises questions as to the ultimate target in cyanide-induced lethality.

Two stillborn sisters had characteristics of both agnathia and holoprosencephaly. Familial occurrence implies that agnathia-holoprosencephaly may be determined by a single recessive gene, something to be taken into account when counseling such families. Evidence from human experience and various animal models suggests that agnathia-holoprosencephaly represents a causally heterogeneous single developmental field defect. Anatomical studies of these two stillborn sisters support the view that they shared a developmental field defect which affected structures in the face, cranial cavity, and upper neck. The pathogenesis of these variably expressed defects probably relates to defects in neural crest cells of cranial origin and/or to underlying mesodermal support elements of these cells.

The objectives of this study were to evaluate a technique for routine, noninvasive measurement of systemic arterial blood pressure and heart rate (HR) in conscious Beagle dogs for toxicologic research. HR, systolic, diastolic, and mean arterial (MAP) pressures were measured with a DINAMAP research monitor (Model 1255, Critikon, Inc.) as follows: Dogs were restrained in a Harvard dog sling, a neonatal cuff was wrapped around the base of the tail, and blood pressure and HR were determined once a minute. Initially, normal values were obtained, 5-10 trials/session, one to three sessions/day for 15 days in six dogs. The day to day, session to session, and trial variabilities were determined and found to be minimal. The day to day diastolic pressure ranged from 74 +/- 18 to 91 +/- 13 mm Hg, systolic pressure from 125 +/- 25 to 156 +/- 22 mm Hg, MAP from 94 +/- 20 to 113 +/- 15 mm Hg, and HR from 111 +/- 21 to 126 +/- 24 beats/minute (bpm). The effects of various drugs on these parameters were determined. Norepinephrine increased diastolic, systolic, and MAP by 75 to 110 mm Hg and decreased HR by half. Epinephrine increased HR by 20 bpm. Phentolamine decreased diastolic, systolic, and MAP by up to 25 mm Hg. Isoproterenol increased HR by up to 130 bpm and decreased diastolic, systolic, and MAP by 20 mm Hg. In addition, the effect of a classic drug interaction on these parameters was determined. When dogs pretreated with the monoamine oxidase inhibitor tranylcypromine were challenged with tyramine, diastolic, systolic, and MAP pressures were increased, whereas HR was decreased.(ABSTRACT TRUNCATED AT 250 WORDS)

The variations and defects observed during detailed gross anatomical dissections of four cases of trisomy 13 are described. Emphasis is on the muscular system where previously undocumented variations, absences, and supernumerary elements were observed. A muscle phenotype which includes absence of palmaris longus, palmaris brevis, plantaris, and peroneus tertius, the presence of pectorodorsalis muscles and muscles from the central tendon of the diaphragm to the pericardium near the pulmonary veins, and variations in the extensor indicis, extensor carpi radialis longus and brevis, biceps, and suprahyoid muscles is discussed. The brain defects which include absent olfactory bulbs and tracts and hypoplastic commissures are compared to those defects seen in cases of alobar holoprosencephaly wherein severe defects of the ethmoid bone are concomitants. Previously well-documented defects of the viscera are included.

A male infant with the Meckel syndrome was studied anatomically. The findings were compared with those from eight trisomy-13 cases to determine whether or not the superficial similarities between the two syndromes were matched by similarities in the internal variations. Emphasis was on the head and limbs. In the head, major differences were found in the nasal bones, mandible, and tongue. In the limbs, the skeletal variations were more severe in the Meckel syndrome infant, but he lacked the muscle variations diagnostic of trisomy 13.

Trisomic and normal control embryos 9.5 through 12 gestational days were examined externally and on serial section with standard light microscopy techniques. Trisomic embryos showed significant retardation in length, weight, optic angle, and somite numbers at most times (p less than .05), and were 1/2 day behind normal animals in overall development. The eye showed the most defects, and these appeared at every period. They included aphakia, large intraretinal space, and dysmorphia of optic cup layers. Brain defects were found at all times. The most common were narrow brain vesicles and folding of the vesicle walls. Some animals showed neural tube defects. The major defect in neural crest derivatives was deficient frontonasal processes in the most defective embryos. The study supports the conclusion of previous investigators that Ts 1 is a syndrome of growth and developmental retardation with a wide range of defects. Definitive evidence, previously lacking, indicates that developmental delay and defective morphogenesis are apparent before 11 days of gestation. In addition, according to our measurements, optic angles are larger in trisomic mice than in normal littermates. This is in contrast to the only previous investigation that included such measurements. Our data do not give definitive support to the suggestion that trisomy 1 belongs to the holoprosencephaly-cyclopia spectrum. However, the hypothesis that murine trisomy 1 shows a parallel in development to human trisomy 13 is not supported by our data. Possible causal mechanisms for the defects and developmental delay are discussed.

We report the anatomic variations found in four additional cases of trisomy 13. Data from these and four previous cases [Colacino and Pettersen, 1978] are utilized to define a muscle phenotype. Previously unreported defects include the bilateral presence of cervical ribs and the bilateral absence of 12th thoracic ribs in five of the eight cases. One unusual developmental defect of the great vessels is also described. The findings suggest that a definitive diagnosis of trisomy 13 can be made on the basis of six muscle variations.

A male infant with the Meckel syndrome was studied anatomically. The findings were compared to those from eight trisomy 13 cases to determine whether or not the superficial similarities between the two syndromes were matched by similarities in the internal variations. Emphasis was on the head and limbs. In the head, major differences were found in the nasal bones, mandible, and tongue. In the limbs, the skeletal variations were more severe in the Meckel syndrome infant, but he lacked the muscle variations diagnostic of trisomy 13.

We reviewed etiologic and phenotypic aspects of those orofacial and limb anomalies usually diagnosed as Hanhart syndrome and Mobius syndrome but also those described, among others, under names such as aglossia-adactylia syndrome, gloss-palatine ankylosis, ankyloglossia superior, peromelia and micrognathia, cleft palate/lateral synechiae syndrome, and the Charlie M. syndrome. By coding the degree of severity of the limb defects it was possible to compare these cases quantitatively and to determine the nosologic significance of associated cranial nerve palsies and chest abnormalities. We analyzed 7 personal and 62 previously reported cases and found: 1. that the severity in the upper limbs and, particularly, malformations of the feet, but not the presence or absence of cranial nerve palsies, is a significant feature in the differentiation of cases, and 2. that the group of patients with cranial nerve palsies includes some with limb defects similar to those in the Hanhart syndrome and others with features which overlap the manifestations of the Poland syndrome. Still other cases had cranial nerve palsy as an isolated trait or as a component manifestation of several different syndromes. These findings permit re-definition and nosologic delimitation of the various syndromes as follows: 1. The Hanhart-syndrome: usually severe limb defect of at least one hand or foot, frequently associated with severe oral abnormalities and sometimes also with cranial nerve palsy. Most cases reported as aglossia-adactylia syndrome, aglossia-hypomelia syndrome, and some cases reported as glossopalatine ankylosis, ankyloglossia superior and Mobius syndrome describe instances of the Hanhart syndrome. 2. The Poland-Mobius syndrome: we suggest this term to refer to those cases of "Mobius syndrome" which have a chest defect and/or symbrachydactyly of the type seen in the Poland syndrome. We suspect that these cases of the "Mobius syndrome," and most of the cases which are usually diagnosed as Poland syndrome represent a different spectrum of the same condition, hence the term Poland-Mobius syndrome. 3. The autosomal dominant cleft palate/lateral synechiae syndrome delineated by Fuhrmann et al. and other apparently less frequent conditions are mentioned in the discussion. Cranial nerve palsy obviously occurs in several etiologically distinct conditions. An analogous situation is present, although less obvious, in the Hanhart and the Poland-Mobius syndrome. Both of these conditions are formal genesis malformation syndromes which implies that they are etiologically non-specific developmental field complexes. In the Hanhart syndrome Bersu et al. postulate a common pathogenetic disturbance for oral and limb defects, thus suggesting that the manifestations represent a single anomaly rather than a "syndrome." This anomaly, for which we suggest the term Kettner anomaly, may occur not only in the Hanhart syndrome but also in other conditions. Similarly, the Poland anomaly, i.e...