Body Wall Defects: Gastroschisis and Omphalocoele in Pigs (Sus scrofa domesticus).

Body wall defects (BWDs) are not well studied and categorized in veterinary medicine. BWDs can be an isolated occurrence, but often occur with other major developmental abnormalities. Thirty-two body wall malformations of domestic pigs (Sus scrofa domesticus) are presented and classified, distinguishing between body wall dysplasia (umbilical hernia, abdominal wall distension and gastroschisis), omphalocoele and thoracoabdominoschisis (Cantrell syndrome, shistosomus reflexus, body stalk anomalies).

Prune Belly Syndrome in the Pig (Sus scrofa domesticus).

Prune belly syndrome (PBS) is a rare multisystemic disease characterized by a deficiency of abdominal wall musculature, urinary tract anomalies and bilateral intra-abdominal testes. PBS in females is called pseudo prune belly syndrome (PPBS) and is characterized by abdominal wall laxity and urinary tract defects. We report three male and one female stillborn piglets with abdominal distension, hypoplastic abdominal wall musculature and urinary tract anomalies. Bilateral cryptorchidism was observed in the males. In addition, two males showed anomalous liver lobulation, one of them had an anomalous spleen and the other an atrial septal defect. As far as we know, neither PBS nor PPBS have been reported in veterinary literature until now.

Cantrell Syndrome (Thoracoabdominal Ectopia Cordis; Anomalous Umbilical Cord; Diaphragmatic, Pericardial and Intracardiac Defects) in the Pig (Sus scrofa domesticus).

Pentalogy of Cantrell (PC) is a complex body wall defect, involving the abdominal wall, sternum, diaphragm, pericardium and heart. We report on six stillborn piglets with anomalous umbilical cord (UC), cranio-umbilical abdominal defect, cleft sternum, incomplete diaphragm and pericardium, ectopia cordis and intracardiac anomalies. Anomalous UC was defined as a single umbilical artery (SUA) and/or short cord, or as an UC with atypical coiling pattern. The embryonic period, in which all the anomalies found in these piglets develops, coincides with that of UC formation in the pig. We propose that anomalous UC should be considered a sixth defect in Cantrell syndrome (CS), considering that the insult leading to the classical malformations of PC and UC abnormalities is the same or that the sequence of malformations itself may alter the early fetoplacental blood flow and therefore the normal development of the UC angioarchitecture. CS has not been reported previously in animals.

Anatomical Variations of the Blood Vascular System in Veterinary Medicine. The Internal Iliac Artery of the Dog. Part Two.

The aim of this study was to investigate the variability of the internal pudendal artery. Two hundred and thirty-two pelvic halves from 116 adult dogs were examined. Twenty-six anatomical variations were found, thirteen occurring in more than 5% of the dogs. Anatomical variations were grouped in relation to the origin of the prostatic/vaginal arteries, middle rectal artery, urethral artery, ventral perineal and caudal rectal arteries. The chi-squared test was used to analyse differences in sex, side of the body, profile and size, and the results were considered statistically significant when P ≤ 0.05. An identical vascular pattern in both hemipelvises was found for most of the anatomical variations described.

Anatomical Variations of the Blood Vascular System in Veterinary Medicine: The Internal Iliac Artery of the Dog - Part Three.

The aim of this study was to analyse and describe the variability of the umbilical artery. Two hundred and thirty-two pelvic halves from 116 adult dogs were examined. To study the permeability of the umbilical artery, ten adult dogs, nine newborns and thirteen foetuses between 35 and 50 days of gestation were also used. In relation to the origin of the umbilical artery, six anatomical variations were found. From which five involved a cranial (n = 4) or caudal (n = 1) relocation of its origin, and in one case (n = 1), the umbilical artery arose from the median sacral artery. In eight cases, the umbilical artery gave off the prostatic (n = 1) or vaginal (n = 7) arteries. The permeability of the umbilical artery was the most significant anatomical variation: permeability was detected in 45% (106 of 232 pelvic halves) of all cases, from which 36 were males and 70 females. Interestingly, an equal vascular permeability in both hemipelvises was found for 82% of the dogs, thus additional data related to such feature of the umbilical artery was also recorded. In accordance with the statistical study, the main anatomical variations described showed significant values for gender, side of the body, size and profile variables.

Anatomical Variations of the Blood Vascular System in Veterinary Medicine: The Internal Iliac Artery of the Dog: Part One.

Traditional veterinary anatomical models describe the branches of the caudal gluteal artery as the iliolumbar, cranial gluteal, lateral caudal, satellite of the ischiatic nerve and dorsal perineal arteries. However, some classical veterinary anatomy textbooks often indicate variations the general organization of the arterial tree, without giving any pattern of origin or illustrations of the different branching. The aim of this study was to investigate the presumptive variability of the caudal gluteal artery. Two hundred and thirty-two pelvic halves from 116 adult dogs were examined. Twelve anatomical variations were found, nine occurring in more than 5% of the dogs, and three in <5%. A 'long-type' internal iliac artery, which means short caudal gluteal and internal pudendal arteries, was identified, while a 'perineal trunk' was observed as an interesting arterial variation. If the caudal segment alone is taken into consideration, identical vascular patterns in both hemi-pelvises are found in 17% of the dogs. Significant statistical correlation was found for four different types of anatomic variations and gender, two types of variations and body size, one type of variation for body side and one type of variation for head shape.

Distinct vascular zones in the canine prostate.

The vascular bed of canine prostate was studied and detailed distinct vascular zones were visualized on corrosion casts by scanning electron microscopy. This study was performed because of scarce information about the zonal vascularization of the prostate gland in dogs. There are no studies for three-dimensional microvascular distribution of the capsular vessels and the capsular microvascular trabeculae. SEM (vascular corrosion casting method) was used to show 3D angioarchitecture of the prostate gland. The lobules on the dorsal and lateral surface of the gland were numerous but small. Their small size is probably due to the abundant blood supply in the region. Few but large ventral lobules were observed. Three prostatic zones were clearly defined: capsular, parenchyma, and urethral. The diameter of the venous blood vessel compared to arterial vessels of the capsule was smaller. Two types of arteries were observed in trabeculae: direct and branched. The direct arteries were straight, with only a few branches. The branched arteries contained many bifurcations, with the vessel's diameter decreasing gradually. The trabeculae capillary network formed loops, with frequent sphincter-like constrictions and pouch-like protuberances.

Effect of anticoagulation and lavage prior to casting of postmortem material with Mercox and Batson 17.

In this study we compare the quality of vascular casts, obtained from organs of several animal species from different sources and sacrificed under different conditions. Organs from healthy animals were injected with two different polymers such as Mercox and Batson No. 17. When the specimens were observed under a scanning electron microscope structural elements such as endothelial nuclear impressions on vessels and capillaries, endothelial cell borders, venous valves, imprints of smooth muscle cells and intra-arterial cushions were identified. Organs excised post mortem from large animals can be used for microvascular corrosion casting studies with optimal results.

Microvasculature of the gastric mucosa in dogs.

A corrosion casting technique was used to study differences in the microvascular architecture of the pars cardiaca, the fundus ventriculi, the corpus ventriculi and the pars pylorica of the canine gastric mucosa. This technique revealed an unusual arrangement of the microvascular architecture in the nonglandular region surrounding the esophageal opening. Capillaries run tortuously along the mucosal surface parallel to the long axis of the esophagus, and some capillaries form a polygonal network that extends around the seromucous glands. In contrast, the mucosal capillaries of the glandular regions of the stomach are arranged in a symmetric pattern associated with the gastric glands. There are also differences in the mucosal microvessels of the cardiac and fundic areas compared to the corpus and the antrum. In the cardiac and fundic regions, a sparse microvascular pattern was observed and fewer capillaries drained into a single venule. However, the vessels surrounding the gastric glands in the corpus and antral areas drained into venules perpendicular to the hexagonal arrangement of the capillaries.

In vitro response of the brown bullhead catfish cell line, BB, to aquatic pollutants.

Established cell lines from brown bullhead catfish (BB) and rainbow trout (RTG-2) and primary cultures of cells derived from gill, fin, and gonad tissues from brown bullhead catfish were evaluated for use as bioindicators in the neutral red cytotoxicity assay. The BB and RTG-2 cells were compared after a 1 day exposure to chlorinated pesticides and after a 6-day exposure to various polycyclic aromatic hydrocarbons. The BB cells were more sensitive to both classes of chemicals. The sequence of toxicity for the BB cells was 4,4'-DDD. 4,4'-DDT greater than aldrin, 4,4'-DDE and 7,12-dimethylbenz(a)anthracene (DMBA) greater than 3-hydroxybenzo(a)pyrene (3-OH-B(a)P) greater than benzo(a)pyrene (B(a)P). For the RTG-2 cells, the sequence was aldrin greater than 4,4'-DDD greater than 4,4'-DDT greater than 4,4'-DDE and 3-OH-B(a)P greater than DMBA greater than B(a)P. The BB cells were also sensitive to benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)anthracene, and trans-7,8-dihydro-7,8-dihydroxybenzo(a)pyrene. The responses of BB and RTG-2 cells were compared with those of primary cultures after a 1 day exposure to B(a)P. After 1 day of exposure, the RTG-2 cells and primary cultures were more sensitive than the BB cells to B(a)P. Apparently, after 1 day of incubation the RTG-2 and primary cells metabolized greater amounts of B(a)P to cytotoxic metabolites, than did the BB cells. However, by 6 days of incubation, the BB cells were more sensitive to B(a)P than were the RTG-2 cells. A 6-day exposure to B(a)P was not performed with the primary cell cultures.

Rapid chemosensitivity assay with human normal and tumor cells in vitro.

Neutral red assay, as an index of cytotoxicity, has been applied to predictive screening of chemotherapeutic agents. Human hepatoma and melanoma tumor cells and normal melanocytes, keratinocytes, and fibroblasts were incubated for 2, 24, and 48 h with graded concentrations of cis-platinum (0.1 to 80 microM), doxorubicin (0.01 to 100 microM), and 5-fluorouracil (1 to 1000 microM). Cells were most sensitive after 48 h. Tumor cells, based on 50% toxicity values, were 2-4 times more sensitive than the normal cells, except for cis-platinum, where only melanoma cells, as compared to normal melanocytes, showed a marked difference in cytotoxic response. Methotrexate (1 to 10 microM) toxicity could be reversed in the presence of 100 microM of leucovorin. This sensitive, rapid, and economical assay is suitable for preclinical screening and drug development.

Effect of methylazoxymethanol acetate on bluegill sunfish cell cultures in vitro.

An epithelioid cell line derived from fin tissue of bluegill sunfish (designated BG/F) exhibited early indications of cell transformation upon exposure to methylazoxymethanol acetate (MAM acetate). Such changes included the induction of polyploidy, increased colony-forming efficiency, loss of contact inhibition, and formation of transformed foci. Unlike later transformation characteristics observed with mammalian cells, the MAM acetate-treated BG/F cells could not be propagated under conditions of anchorage independence in soft agar. Incubation of BG/F cells with N-methyl-N'-nitro-N-nitrosoguanidine, followed by exposure to 12-O-tetradecanoylphorbol-13-acetate, was not observed to cause cell transformation under the experimental conditions. The controls of a fibroblastic cell culture derived from gill tissue of bluegill sunfish showed spontaneous transformation after 6 months of passage, similar to the transformation observed in the experimental MAM acetate treated gill cultures.

Arsenic-selenium interactions determined with cultured fish cells.

A fibroblastic cell line derived from gill tissue (designated BG/G) and an epithelioid cell line derived from fin tissue (designed BG/F) of bluegill sunfish (Lepomis macrochirus) were used as the bioindicators in toxicity experiments. The neutral red in vitro cytotoxicity assay served as the endpoint. In both cell lines the sequence of observed cytotoxicity was arsenite greater than arsenate greater than selenite greater than selenate, with each cell type exhibiting comparable ranking of midpoint toxicity (NR50) concentrations. Antagonistic interactions were noted between combinations of arsenics and seleniums. Thus, selenate and selenite (at nontoxic levels) reduced, but did not eliminate, the acute cytotoxicities of arsenate and, to a lesser extent, of arsenite.

Comparisons of two in vitro cytotoxicity assays-The neutral red (NR) and tetrazolium MTT tests.

The neutral red (NR) and tetrazolium MTT in vitro cytotoxicity assays were compared for 28 test agents of widely varying potency using the BALB/c mouse 3T3 fibroblast cell line as the bioindicator. For any given cell density in the microtitre plate well, the optical density absorbance with the NR assay was about twice that obtained with the MTT assay. However, there was good agreement (r = 0.939) between the ranking of the test agents on the basis of midpoint cytotoxicity values (NR(50) and MTT(50)), although the assays were based on different physiological endpoints. Nevertheless, the two assays were found to differ in sensitivity for a few test agents, such as chloroquine sulphate and several antineoplastic drugs. Both assays were capable of demonstrating a reduction in the cytotoxicity of methotrexate by leucovorin.

Mediating role of metabolic activation in in vitro cytotoxicity assays.

Enzymatic activation of polycyclic aromatic hydrocarbons (PAHs) and its effect on cytotoxicity were studied using the neutral red viability assay as the end point. Benzo[a]pyrene was progressively cytotoxic to human hepatoma (HepG2) cells over a 1- to 3-d period, and after induction of monooxygenase activity with a polychlorobiphenyl (PCB) mixture (Arochlor 1254), cytotoxicity was increased about threefold. Concomitant with Arochlor exposure was an increase in the activity of 7-ethoxycoumarin odeethylase, which could be inhibited by exposure to alpha-naphthoflavone. Human keratinocytes (NHEK), but not fibroblasts (HFF), were sensitive to the cytotoxicity of benzo[a]pyrene. However, preexposure of the keratinocytes to Arochlor did not increase their sensitivity to benzo[a]pyrene. Neither the keratinocytes, fibroblasts, nor HepG2 cells were sensitive to acenaphthene. Addition of hamster or rat hepatic S9 mix, however, resulted in toxicity from benzo[a]pyrene and acenaphthene. 7,12-Dimethylbenz[a]anthracene was only mildly cytotoxic to the fibroblasts, and its cytotoxicity was not enhanced in the presence of rat or hamster S9 mix. Exposure of the HepG2 cells to 7,12-dimethylbenz[a]anthracene showed progressive toxicity over a 1- to 3-d period. Prior exposure of the HepG2 cells to Arochlor did not enhance their sensitivity to 7,12-dimethylbenz[a]anthracene. Human keratinocytes were sensitive to 7,12-dimethylbenz[a]anthracene, with cytotoxicity markedly increasing over a 1- to 3-d period.