Cytogenetic abnormalities of unfertilized oocytes generated from in-vitro fertilization and intracytoplasmic sperm injection: a double-blind study

In the present study we have assessed the cytogenetic abnormalities of unfertilized oocytes from in-vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) programmes during a one year period (July 1995 to July 1996) with the cytogenetic analysis being carried out in a double-blind manner. A total of 88 unfertilized ICSI and 85 unfertilized IVF oocytes were used for the study and of these 51 and 62 oocytes, in each respective group, were suitable for analysis. The haploidy, diploidy and aneuploidy rates between ICSI (62.7, 7.8 and 5.9%) and IVF (61.3, 9.7 and 14.5%) groups were similar. A significant inter-patient variation in the incidence of hypohaploidy was observed within the IVF group. Chromosomal fragmentation or breakage was observed at a similar rate in both groups of unfertilized oocytes (23.5 and 14.5% for ICSI and IVF respectively). A significantly higher proportion of ICSI oocytes contained sperm nuclei (27/51, 52.9%) than did IVF oocytes (20/62, 32.3%, P < 0.01). The distribution and state of sperm head chromatin in relation to oocyte chromosomal complement was studied in both groups. ICSI oocytes contained decondensed or swollen sperm nuclei in association with haploid oocyte chromosomes (12/27, 44.4%) or condensed sperm heads in oocytes showing no chromosomal complements (7/27, 25.9%). In IVF oocytes sperm heads were either arrested in the condensed state (5/20, 25%), metaphase stage (3/20, 15%) or had undergone premature chromosome condensation (PCC; 6/20, 30%) in association with haploid oocyte chromosomes. The incidence of PCC was similar in the two groups. A marked variation in the incidence of total chromosomal abnormality was observed between patients within both ICSI (0-75%) and IVF (0-71%) groups indicating a possible similarity in oocyte quality between the majority of male factor and tubal infertility patients. The type of sperm used in the two fertilization procedures showed an increased incidence of chromosomal breakage with ICSI-MESA (microepididymal sperm aspiration) spermatozoa (4/6, 67%) compared to the ICSI-ejaculated (6/35, 17.1%; P < 0.05), ICSI-testicular biopsy (2/10, 20%) and IVF-normospermic (9/62, 14.5%; P < 0.01) spermatozoa. Chromosomal fragmentation may be associated with the degree of difficulty experienced at sperm injection, especially with sperm retrieved from the reproductive tract. Thus chromosomal fragmentation in ICSI may need further investigation using a larger sample size in order to assess the possible causative factors.     

Nitroreduction of 2,4-dinitrotoluene in vitro by cytochrome P-450 induced H4IIE cells

Conditions have been established for H4IIE rat hepatoma cell cultures in which effects of cytochrome P-450 induction on the metabolism of a munitions wastestream pollutant can be studied. Under these conditions, the polychlorinated hydrocarbon 2,3,4,7,8-pentachlorodibenzfuran (PCDBF) induced cytochrome P-450 (1A1) aryl hydrocarbon hydroxylase (AHH) activity over a wide range of concentrations without significant cytotoxic effects. The munition pollutant 2,4-dinitrotoluene (2,4-DNT) did not induce AHH activity itself, but its metabolism was considerably altered when applied to PCDBF induced cultures. Production of amino nitrotoluene isomers was greatly enhanced in induced cultures as compared to uninduced controls, as was the conversion of radiolabeled 2,4-DNT to relatively more polar metabolites. To some extent, the results with H4IIE cells parallel those reported for animals exposed to 2,4-DNT after induction of cytochrome P-450 AHH activity. The preliminary findings suggest that with further development and validation, H4IIE cultures could be of use in characterizing metabolites that result from exposure to chemical mixtures involving a P-450 (1A1) inducer.     

A role for 4-hydroxynonenal, an aldehydic product of lipid peroxidation, in disruption of ion homeostasis and neuronal death induced by amyloid beta-peptide

Peroxidation of membrane lipids results in release of the aldehyde 4-hydroxynonenal (HNE), which is known to conjugate to specific amino acids of proteins and may alter their function. Because accumulating data indicate that free radicals mediate injury and death of neurons in Alzheimer's disease (AD) and because amyloid beta-peptide (A beta) can promote free radical production, we tested the hypothesis that HNE mediates A beta 25-35-induced disruption of neuronal ion homeostasis and cell death. A beta induced large increases in levels of free and protein-bound HNE in cultured hippocampal cells. HNE was neurotoxic in a time- and concentration-dependent manner, and this toxicity was specific in that other aldehydic lipid peroxidation products were not neurotoxic. HNE impaired Na+, K(+)-ATPase activity and induced an increase of neuronal intracellular free Ca2+ concentration. HNE increased neuronal vulnerability to glutamate toxicity, and HNE toxicity was partially attenuated by NMDA receptor antagonists, suggesting an excitotoxic component to HNE neurotoxicity. Glutathione, which was previously shown to play a key role in HNE metabolism in nonneuronal cells, attenuated the neurotoxicities of both A beta and HNE. The antioxidant propyl gallate protected neurons against A beta toxicity but was less effective in protecting against HNE toxicity. Collectively, the data suggest that HNE mediates A beta-induced oxidative damage to neuronal membrane proteins, which, in turn, leads to disruption of ion homeostasis and cell degeneration.     

Paget bone disease involving young adults in 3 generations of a Korean family

Pancreatic cancer is an aggressive disease with a dismal prognosis. It has long been regarded as one of the most difficult cancers to accurately diagnose and stage preoperatively. The purpose of this review is to provide an update of the state-of-the-art for early detection, diagnosis, and staging of pancreatic cancer. These methods include spiral CT scans, magnetic resonance imaging, positron emission tomography (PET) imaging, laparoscopy, endoscopic ultrasound, CA 19-9 serology, fine needle aspiration cytology, ERCP brush cytology, and screening for p53 and ras oncogenes. These advanced techniques should help us to detect pancreatic cancers in high-risk populations at a curative stage and to decrease pancreaticoduodenectomies for benign disease which could otherwise be treated with less morbid procedures. In addition, these tests will help reliably diagnose pancreatic cancer preoperatively.     

Accelerated inflammatory bowel disease of TCR-alpha-deficient mice persistently infected with Cryptosporidium parvum

TCR-alpha-deficient mice spontaneously develop inflammatory bowel disease (IBD) at 8-9 mo old. This study characterizes an accelerated form of IBD induced by Cryptosporidium parvum infection. Cryptosporidium parvum-infected TCR-alpha-deficient mice developed IBD as early as 4 wk old when challenged at 1 wk old. The lesions of this accelerated IBD resembled the lesions of spontaneous IBD in TCR-alpha-deficient mice and consisted of a mononuclear cell infiltrate within the intestinal lamina propria and an increased proliferation of enterocytes. The mononuclear cells within the lamina propria consisted of B cells and gamma delta T cells. The distal ileum, cecum, and colon were grossly thickened due to a hyperplastic mucosa and edematous submucosa. The mechanism by which C. parvum infection accelerates development of IBD is presently unclear.     

Innate immunity, cytokines, and pulmonary host defense

Effective host defense against bacterial infection is dependent on the activation and recruitment of phagocytic cells. The initiation, maintenance, and resolution of this inflammatory response in the setting of bacterial pneumonia is dependent on the expression of cytokines. As the complexities of the host-pathogen interaction are further dissected and unraveled, immunologic manipulation of cytokine expression will likely become an important adjuvant therapy in the treatment of serious lung infections.     

Sequencing of RAPD fragments amplified from the genome of the prokaryote Prochlorococcus marinus (prochlorophyta)

DNA fingerprint patterns from the chlorophyll a and b containing prokaryote Prochlorococcus marinus were generated with the RAPD technique using two primers derived from repetitive sequence motifs, [(GATA)4 and M13] and a random primer (OPB-10]. Five RAPD fragments were reamplified, cloned and sequenced. The clones M13/1300 and OPB-10/1100 contained open reading frames, whereas the (GATA)4 fragments were interrupted by stop codons in all frames indicating their noncoding function and possessed a high AT score of 63% and 71%, respectively. With the two (GATA)4 clones and the M13/300 clone strain-specific signals were obtained in a Southern blot analysis of various Prochlorococcus strains. Clones M13/1300 and OPB-10/1100, containing the ORFs, produced RFLPs between the strains analyzed. All RAPD fragments are represented as single copy in the genome of Prochlorococcus.