Animal Models of Barrett's Esophagus and Esophageal Adenocarcinoma–Past,Present, and Future

Esophageal adenocarcinoma is the fastest rising cancer in the United States. It develops from long‐standing gastroesophageal reflux disease which affects >20% of the general population. It carries a very poor prognosis with 5‐year survival <20%. The disease is known to sequentially progress from reflux esophagitis to a metaplastic precursor, Barrett''s esophagus and then onto dysplasia and esophageal adenocarcinoma. However, only few patients with reflux develop Barrett''s esophagus and only a minority of these turn malignant. The reason for this heterogeneity in clinical progression is unknown. To improve patient management, molecular changes which facilitate disease progression must be identified. Animal models can provide a comprehensive functional and anatomic platform for such a study. Rats and mice have been the most widely studied but disease homology with humans has been questioned. No animal model naturally simulates the inflammation to adenocarcinoma progression as in humans, with all models requiring surgical bypass or destruction of existing antireflux mechanisms. Valuable properties of individual models could be utilized to holistically evaluate disease progression. In this review paper, we critically examined the current animal models of Barrett''s esophagus, their differences and homologies with human disease and how they have shaped our current understanding of Barrett''s carcinogenesis.     

ARH missense polymorphisms and plasma cholesterol levels.

Mutations in a putative low-density lipoprotein (LDL) receptor adaptor protein called ARH have been recently described in patients with autosomal recessive hypercholesterolemia (ARH). ARH plays a tissue-specific role in determination of LDL receptor function. In the ARH gene three mismatched polymorphisms have been detected: Pro202Ser, Pro202His and Arg238Trp. These are of putative interest in plasma cholesterol level determination. To evaluate the effect of polymorphisms on plasma cholesterol levels, all polymorphisms were analyzed by PCR and restriction enzyme analysis by MnII, HpyCH4IV and SacII in 100 Caucasian males with high (>90%, 6.29 +/- 0.89 mmol/l), and 100 males with low (<10%, 3.60 +/- 0.57 mmol/l), total plasma cholesterol levels. No significant differences were observed in frequencies of ARH genotypes or alleles between these two extreme groups. These results suggest that ARH polymorphisms are unlikely to be important genetic determinants of plasma cholesterol levels.     

Comparison between isoprenaline infusions and bolus injections to assess beta-adrenoceptor function in man, with special reference to cardiac contractility and the influence of autonomic reflexes.

The present study was performed to characterize cardiovascular responses to isoprenaline and the influence of autonomic reflexes on these responses. Nine healthy volunteers received infusions and bolus injections of isoprenaline before and after 'autonomic blockade' produced by intravenous atropine 0.04 mg kg-1 and clonidine 300 micrograms. Heart rate, blood pressures, systolic time intervals and various echocardiographic measures of cardiac contractility were registered. No significant differences in responsiveness to isoprenaline were seen when infusions were repeated on the same day without 'autonomic blockade'. After 'blockade', delta responses at 1 nmol l-1 isoprenaline (infusions) were increased for diastolic blood pressure and decreased for systolic blood pressure and stroke volume. Bolus injections of 2 micrograms isoprenaline caused enhanced delta responses after 'autonomic blockade' of diastolic blood pressure, left ventricular diameter in systole, ventricular circumferential fibre shortening, mean posterior wall velocity (Vmean PW), stroke volume, systemic vascular resistance, electromechanical systole (QS2) and pre-ejection period. Systolic blood pressure decreased, in contrast to a small increase without 'blockade'. These findings are explained by differences in haemodynamic effects of isoprenaline and by the dependence of responses on reflexes when isoprenaline is administered in different ways. When heart rate was increased by bolus doses of atropine, in the presence of beta-blockade (propranolol), pre-ejection period and left ventricular diameter in systole were unaffected, and Vmean PW and ventricular circumferential fibre shortening showed only small increases (compared with alterations induced by isoprenaline). However, left ventricular ejection time, QS2 and ejection time (by echocardiography), were markedly dependent on heart rate alterations. Thus, pre-ejection period, left ventricular diameter in systole Vmean PW and ventricular circumferential fibre shortening are parameters which can be useful in order to evaluate cardiac beta-adrenoceptor sensitivity in vivo in man.     

Lymphoma incidence in a Swedish county during 1969-1987.

The incidence of lymphoid malignancies (acute leukemias and myelomatosis excluded) during 1969-1987 in the County of Uppsala was calculated on the basis of the regional cancer register and local registers from the only oncological, hematological, dermatological and pathological departments in this well-defined geographical area. Of the 774 patients included, 639 had histopathological specimens available, all of which were re-examined. Seventy-nine patients were diagnosed on the basis of bone marrow investigations (greater than 70% re-examined, all had a low-grade non-Hodgkin's lymphoma = NHL) and 54 on fine-needle aspiration biopsies (not re-examined). Seventy-nine of the lymphoma diagnoses were based on autopsy specimens. The overall age standardized incidence was 16.2/100,000/year (NHL: 13.6, Hodgkin's disease = HD: 1.5) according to the Swedish 1970 census (according to world standard population: 10.2); male: 20.9 (12.9) and female: 12.4 (7.9). The annual change in trend was +3.0% +/- 2.6 (NHL: +3.6% +/- 2.4, HD: no change). The omission of the 54 'fine needle cases' led to an overall incidence of 15.0 (9.7) and an annual change in trend of +3.5% +/- 1.9. Among the histopathological specimens, an NHL was found in 524 patients and HD in 69. In 46 registered patients, the diagnosis malignant lymphoma was wrong. The diagnosis changed to NHL in 43 patients registered as HD.     

Hypocalcemic symptoms during plateletpheresis using the COBE Spectra: A comparison of oral combination of 600mg calcium+300mg magnesium+100IU vitamin D3 vs. a 1000mg calcium in symptomatic donors.

BACKGROUND: The aim of this study was to find an effective treatment for hypocalcemic symptoms during plateletpheresis and to evaluate if a combination of calcium, magnesium and vitamin D3 is more effective in comparison to routine calcium supplementation. MATERIAL AND METHODS: A study group consisting of 10 donors, having a history of previous hypocalcemic symptoms during plateletpheresis, donated platelets twice in a one-month period. During the first donation combination tablets (600mg Ca+300mg Mg+100IU vitamin D3) were used to treat hypocalcemic symptoms while routine treatment calcium carbonate tablets (1000mg Ca) were used during the second donation. If symptoms persisted after 10min the same dose was repeated. A control group, with no supplementation, consisting of five donors, with no history of hypocalcemic symptoms, were included. Donor subjective symptoms were graded and recorded on four occasions: at the start of plateletpheresis, when symptoms appeared, 10min after the first tablet and at the end of donation. Samples for analysis of ionized calcium (iCa), magnesium and potassium were also taken at the same occasions. RESULTS: All donors from the study group experienced minor or medium hypocalcemic symptoms and needed a second dose of supplementation. Calcium carbonate tablets completely relieved the hypocalcemic symptoms in six donors, it had no effect on three donors and one donor experienced aggravated symptoms. The combination tablets completely relieved the symptoms in three donors, one donor experienced a partial relief and six donors had no relief of symptoms. There were no significant differences in iCa, potassium and magnesium levels were noted in the study group irrespective of which tablets were used for treatment of hypocalcemic symptoms. After plateletpheresis the median iCa levels declined by 30% and potassium levels declined by 3-11% in all donors while the magnesium levels were not significantly affected. There was no correlation between the presence of symptoms and the changed levels of iCa or magnesium. CONCLUSION: Addition of magnesium and vitamin D3 to calcium seems to have no beneficial effect in the treatment of hypocalcemic symptoms in plateletpheresis donors.     

Mothers' Anticipation and Prevention of Unintentional Injury to Young Children in the Home

Investigated anticipation and prevention of children's unintentionalinjuries in the home. 150 mothers of 1-, 2-, and 3-year-oldchildren kept weekly diaries of anticipated injuries and unanticipatedinjuries/near injuries to their child. Mothers anticipated between57 and 67% of all injury events, a majority when the child wasin the same room as the injury-causing agent prior to interactingwith it. Few anticipated injuries led to injury. In these casesno significant differences were found depending on child's ageand sex. In contrast, mothers of younger children most frequentlyreported preventing injury by physically restricting or movingthe child away and by changing the environment, whereas mothersof older children more frequently engaged in teaching.     

Chemoattractant-induced NADPH oxidase activity in human monocytes is terminated without any association of receptor-ligand complex to cytoskeleton

When the chemotactic peptide formylmethionyl-leucyl-phenylalanine binds to its cell surface receptor, a transmembrane signal is generated that activates the superoxide-producing NADPH oxidase of human phagocytes. Comparing monocytes and neutrophils with regard to the production of superoxide anion induced by the peptide, we found a similar time-course for both types of cells. In neutrophils, ligand binding induced a conversion of the receptor to a high-affinity form, a change suggested to be due to an association of the receptor-ligand complex to the Triton X-100-insoluble cytoskeleton. This event has been hypothesized to terminate the signal that activates the NADPH oxidase and thereby results in cessation of the cellular production of superoxide anion. Neutrophils preincubated with the cytoskeleton-disrupting drug cytochalasin B showed an increased and prolonged superoxide anion production after activation with the peptide, thus indicating that the cytoskeleton is involved in terminating this response. Formylmethionyl-leucyl-phenylalanine was also found to induce polymerization of actin in monocytes; however, cytochalasin B had no effect on the peptide-induced generation of superoxide anion in these cells. Furthermore, also in monocytes, ligand binding induced a conversion of the receptor to a high-affinity form; however, the receptor-ligand complex did not coisolate with the Triton X-100-insoluble cytoskeleton. These results indicate that, in monocytes, the NADPH oxidase activating pathway is terminated without any association of the receptor-ligand complex to the Triton X-100-insoluble cytoskeleton.     

Heligmosomoides polygyrus inhibits established colitis in IL-10-deficient mice

Inflammatory bowel disease (IBD) is prevalent in industrialized countries, but rare in less-developed countries. Helminths, common in less-developed countries, may induce immunoregulatory circuits protective against IBD. IL-10(-/-) mice given piroxicam develop severe and persistent colitis. Lamina propria mononuclear cells from colitic IL-10(-/-) mice released IFN-gamma and IL-12. The ongoing piroxicam-induced colitis could be partially blocked with anti-IL-12 monoclonal antibody suggesting that the inflammation was at least partly IL-12 dependent. Colonization of piroxicam-treated colitic IL-10(-/-) mice with Heligmosomoides polygyrus (an intestinal helminth) suppressed established inflammation and inhibited mucosal IL-12 and IFN-gamma production. H. polygyrus augmented mucosal IL-13, but not IL-4 or IL-5 production. Transfer of mesenteric lymph node (MLN) T cells from IL-10(-/-) animals harboring H. polygyrus into colitic IL-10(-/-) recipients inhibited colitis. MLN T cells from worm-free mice did not. Foxp3 (scurfin) drives regulatory T cell function. H. polygyrus enhanced Foxp3 mRNA expression in MLN T cells that had regulatory activity. This suggests that H. polygyrus inhibits ongoing IL-10(-/-) colitis in part through blocking mucosal Th1 cytokine production. Resolution of inflammation is associated with increased IL-13 production and can be adoptively transferred by MLN T cells.     

Phenotype delineation of ZNF462 related syndrome

Zinc finger protein 462 (ZNF462) is a relatively newly discovered vertebrate specific protein with known critical roles in embryonic development in animal models. Two case reports and a case series study have described the phenotype of 10 individuals with ZNF462 loss of function variants. Herein, we present 14 new individuals with loss of function variants to the previous studies to delineate the syndrome of loss of function in ZNF462. Collectively, these 24 individuals present with recurring phenotypes that define a multiple congenital anomaly syndrome. Most have some form of developmental delay (79%) and a minority has autism spectrum disorder (33%). Characteristic facial features include ptosis (83%), down slanting palpebral fissures (58%), exaggerated Cupid's bow/wide philtrum (54%), and arched eyebrows (50%). Metopic ridging or craniosynostosis was found in a third of study participants and feeding problems in half. Other phenotype characteristics include dysgenesis of the corpus callosum in 25% of individuals, hypotonia in half, and structural heart defects in 21%. Using facial analysis technology, a computer algorithm applying deep learning was able to accurately differentiate individuals with ZNF462 loss of function variants from individuals with Noonan syndrome and healthy controls. In summary, we describe a multiple congenital anomaly syndrome associated with haploinsufficiency of ZNF462 that has distinct clinical characteristics and facial features.     

PMM2 mutation spectrum, including 10 novel mutations, in a large CDG type 1A family material with a focus on Scandinavian families

Carbohydrate-deficient glycoprotein syndrome type IA (CDG IA) is an autosomal recessive disease characterized clinically by severe involvement of the central and peripheral nervous system, and biochemically by complex defects in carbohydrate residues in a number of serum glycoproteins. CDG IA is caused by mutations in the PMM2 gene located in chromosome region 16p13. In this study, 61 CDG type IA patients (122 chromosomes) were screened for mutations in the PMM2 gene using a combination of SSCP and sequence analysis. More than 95% of the mutations could be detected. All of them were missense mutations. Mutations 422G>A and 357C>A were strikingly more common in the material and comprised 58% of mutations detected. Of the 20 mutations found, 10 were not reported previously. Seven mutations, e.g. 26G>A (five alleles) and 548T>C (seven alleles), were found only in Scandinavian families. The most common genotype was 357C>A/422G>A (36%). Three patients were homozygous, 357C>A/357C>A (two cases), and 548T>C/548T>C (one case). No patients homozygous for the most common mutation 422G>A were detected. The different mutations were clustered e.g., in that most were located in exon 5 (five) and exon 8 (six), while no mutation was detected in exon 2. When the frequencies of each mutation were included, exon 5 comprised 61% (65 chromosomes) of the mutations; in Scandinavian patients the frequency of these mutations was 72%. Thus, analysis of exon five in these patients enables both reliable and time-saving first screening in prenatal diagnostic cases. This could be followed by a second step of additional strategies for the detection of other mutations.