Restoration of the rat urothelium after cyclophosphamide treatment.

Processes leading to the recovery of a normal three-layered urothelium from a hyperplastic urothelium induced by cyclophosphamide (CP) treatment in rats have been investigated. A single intraperitoneal (ip) dose of CP caused extensive loss of cells from urothelium, but the remaining cells started to express epidermal growth factor receptor (EGFR) in their plasma membranes. On day 2 after CP injection, proliferating cell nuclear antigen (PCNA) immunohistochemistry showed a rapid increase in positively stained nuclei, from which a hyperplastic urothelium developed, composed of undifferentiated cells expressing EGFR over the entire plasma membrane. Subsequently, EGFR gradually disappeared from the apical plasma membrane but remained in the basolateral membranes. After day 6, PCNA-positive nuclei in all cell layers decreased, except in basal cells. Apoptotic cells were detectable by the TUNEL assay at day 2, and increased in number in all layers of the hyperplastic urothelium until day 10, returning to the control levels by day 14. Electron microscopic evidence showed that apoptotic cells were either pinched off into the bladder lumen or phagocytosed by the neighbouring urothelial cells. Thus, the urothelium responds to the damage by intense proliferation for a week, resulting in an undifferentiated hyperplastic state. Differentiation of superficial cells then begins and damaged cells are gradually removed by apoptosis until the three-layered urothelium is fully restored by two weeks following CP treatment.     

Congenital anomalies in the baboon (Papio spp.)

Background A comprehensive survey of the prevalence of congenital anomalies in baboons has not been previously reported. We report the congenital anomalies observed over a 26‐year period in a large captive baboon colony. Methods A computer search was performed for all baboon congenital anomalies identified at necropsy and recorded on necropsy submissions. Results We identified 198 congenital anomalies in 166 baboons from 9972 necropsies (1.66% of total necropsies). The nervous, urogenital, musculoskeletal, and cardiovascular systems were most commonly affected. The most common organs affected were the brain, bone, heart, testicle, kidney, penis, aorta, and skeletal muscle. The most frequent congenital anomalies were blindness, seizures, and hydrocephalus. Conclusions The baboon has an overall frequency of congenital anomalies similar to humans and other non‐human primates. Although the most frequently affected systems are similar, congenital anomalies involving the digestive system appear to be less common in the baboon.     

Chronic cyclophosphamide treatment alters the expression of stress response genes in rat male germ cells

Increases in the survival rate of men treated with chemotherapeutic drugs and their desire to have children precipitate concerns about the effects of these drugs on germ cells. Azoospermia, oligospermia, and infertility are common outcomes resulting from treatment with cyclophosphamide, an alkylating agent. Exposure of male rats to cyclophosphamide results in dose-dependent and time-specific adverse effects on progeny outcome. Elucidation of the effects of chronic low-dose cyclophosphamide treatment on the expression of stress response genes in male germ cells may provide insight into the mechanisms underlying such adverse effects. Male rats were gavaged with saline or cyclophosphamide (6 mg/kg) for 4-5 wk; pachytene spermatocytes, round spermatids, and elongating spermatids were isolated; RNA was extracted and probed on cDNA arrays containing 216 cDNAs. After saline treatment, 125 stress response genes were expressed in pachytene spermatocytes (57% of genes studied), 122 in round spermatids (56%), and 83 in elongating spermatids (38%). Cyclophosphamide treatment reduced the number of genes detected in all germ cell types. The predominant effect of chronic cyclophosphamide exposure was to decrease the expression level of genes in pachytene spermatocytes (34% of genes studied), round spermatids (29%), and elongating spermatids (4%). In elongating spermatids only, drug treatment increased the expression of 8% of the genes studied. The expression profiles of genes involved in DNA repair, posttranslational modification, and antioxidant defense in male germ cells were altered by chronic cyclophosphamide treatment. We hypothesize that the effects of cyclophosphamide exposure on germ cell gene expression during spermatogenesis may have adverse consequences on male fertility and progeny outcome.     

Congenital heart disease and external ear anomalies with hearing loss: a report of two new cases and a review of the literature

Two cases of infants presenting primarily with congenital heart disease and external ear anomalies with hearing loss are reported. There is a clear, clinically important, association between these two birth defects; this association discussed along with a review of other syndromes with such features.     

Congenital atrichia in five Arab Palestinian families resulting from a deletion mutation in the human hairless gene

Congenital atrichia is a rare autosomal recessive disorder of hair development, characterized by complete loss of hair shortly after birth. Evidence of linkage to chromosome 8p12 has been established, implicating the human homolog of the mouse hairless (hr) gene as a candidate gene. We have previously identified missense mutations in families with congenital atrichia. Here, we report the first deletion mutation (2147del C) in exon 9 of the human hairless gene leading to a frameshift and downstream premature termination codon in five Palestinian families of Arab origin. Received: 31 July 1998 / Accepted: 31 August 1998     

Impaired secretion of rat mannose-binding protein resulting from mutations in the collagen-like domain

Serum mannose-binding protein (MBP) or mannose-binding lectin initiates the lectin branch of the innate immune response by binding to the surface of potentially pathogenic microorganisms and initiating complement fixation through an N-terminal collagen-like domain. Mutations in this region of human MBP are associated with immunodeficiency resulting from a reduction in the ability of the mutant MBPs to fix complement as well as from reduced serum concentrations. Inefficient secretion of the mutant proteins, which is one possible cause of the reduced serum levels, has been investigated using a mammalian expression system in which each of the naturally occurring human mutations has been recreated in rat serum MBP. The mutations Gly25-->Asp and Gly28-->Glu disrupt the disulfide-bonding arrangement of the protein and cause at least a 5-fold increase in the half-time of secretion of MBP compared with wild-type rat serum MBP. A similar phenotype, including a 3-fold increase in the half-time of secretion, disruption of the disulfide bonding arrangement, and inefficient complement fixation, is observed when nearby glucosylgalactosyl hydroxylysine residues at positions 27 and 30 are replaced with arginine residues. The results suggest that defective secretion resulting from structural changes in the collagen-like domain is likely to be a contributory factor for MBP immunodeficiency.     

Congenital anomalies and childhood cancer in Great Britain.

The presence of cancer and a congenital anomaly in the same child may be explained in certain cases by an underlying genetic abnormality. The study of these associations may lead to the identification of genes that are important in both processes. We have examined the records of 20,304 children with cancer in Britain, who were entered into the National Registry of Childhood Tumors (NRCT) during 1971-86, for the presence of congenital anomalies. The frequency of anomalies was much higher among children with solid tumors (4.4%) than among those with leukemia or lymphoma (2.6%; P < .0001). The types of cancer with the highest rates of anomalies were Wilms tumor (8.1%), Ewing sarcoma (5.8%), hepatoblastoma (6.4%), and gonadal and germ-cell tumors (6.4%). Cases of spina bifida and abnormalities of the eye, ribs, and spine were more common in children with cancer than among population-based controls. Future studies may be directed toward identifying the developmental pathways and the relevant genes that are involved in the overlap between pediatric cancer and malformation.     

Congenital anomalies in a neonatal white-tailed deer in Alberta.

In September, 1973, a live male 2-3 day old white-tailed deer (Odocoileur virginianus) with multiple anomalies of the head and forelimbs was found near Lethbridge, Alberta. Notable gross findings inculded brachygnathia inferior, atypical incisor tooth alignment, medially folded ears, humero-radial arthrogryposis and bowing of the radius and ulna. Hematologic determinations indicated increased erythrocyte, hemoglobin and hematocrit levels. Histopathologic examination revealed mineralized spherites in the cerebellum and midbrain.