Prevalence of morphologic defects in spermatozoa from beef bulls

OBJECTIVE: To determine the overall prevalence of morphologic defects in spermatozoa from beef bulls and to determine whether prevalence varies with the age of the bull. DESIGN: Cross-sectional observational study. ANIMALS: 2,497 beef bulls that were evaluated for breeding soundness in 1994 by 29 practicing veterinarians in a 5-state geographic region. PROCEDURE: Slides of spermatozoa from each bull were made and submitted by practicing veterinarians for morphologic evaluation. One hundred spermatozoa per slide were examined, and each was classified as having 1 of 9 morphologic defects or as normal. RESULTS: 63% of bulls evaluated were 10 to 12 months old, and 20% were 13 to 18 months old. A mean of 70.6% of spermatozoa was classified as normal. Most common defects were proximal droplets (8.4%), distal midpiece reflexes (6.7%), separated heads (5.5%), and distal droplets (3.8%). Other defects were seen < 2% of the time. Bulls 10 to 12 months of age had a higher prevalence of proximal and distal droplet defects than older bulls. CLINICAL IMPLICATIONS: Practitioners conducting breeding soundness evaluations in beef bulls must be aware of common spermatozoal defects. Bulls that are evaluated at a young age will have more defects than older bulls and should be reevaluated, particularly for those defects for which prevalence decreases with age.     

Inositol 1,4,5-trisphosphate [correction of tris-phosphate] activation of inositol trisphosphate [correction of tris-phosphate] receptor Ca2+ channel by ligand tuning of Ca2+ inhibition

Inositol 1,4,5-trisphosphate (IP3) [corrected] binding to its receptors (IP3R) in the endoplasmic reticulum (ER) activates Ca2+ release from the ER lumen to the cytoplasm, generating complex cytoplasmic Ca2+ concentration signals including temporal oscillations and propagating waves. IP3-mediated Ca2+ release is also controlled by cytoplasmic Ca2+ concentration with both positive and negative feedback. Single-channel properties of the IP3R in its native ER membrane were investigated by patch clamp electrophysiology of isolated Xenopus oocyte nuclei to determine the dependencies of IP3R on cytoplasmic Ca2+ and IP3 concentrations under rigorously defined conditions. Instead of the expected narrow bell-shaped cytoplasmic free Ca2+ concentration ([Ca2+]i) response centered at approximately 300 nM-1 microM, the open probability remained elevated (approximately 0.8) in the presence of saturating levels (10 microM) of IP3, even as [Ca2+]i was raised to high concentrations, displaying two distinct types of functional Ca2+ binding sites: activating sites with half-maximal activating [Ca2+]i (Kact) of 210 nM and Hill coefficient (Hact) approximately 2; and inhibitory sites with half-maximal inhibitory [Ca2+]i (Kinh) of 54 microM and Hill coefficient (Hinh) approximately 4. Lowering IP3 concentration was without effect on Ca2+ activation parameters or Hinh, but decreased Kinh with a functional half-maximal activating IP3 concentration (KIP3) of 50 nM and Hill coefficient (HIP3) of 4 for IP3. These results demonstrate that Ca2+ is a true receptor agonist, whereas the sole function of IP3 is to relieve Ca2+ inhibition of IP3R. Allosteric tuning of Ca2+ inhibition by IP3 enables the individual IP3R Ca2+ channel to respond in a graded fashion, which has implications for localized and global cytoplasmic Ca2+ concentration signaling and quantal Ca2+ release.     

Expression of constitutively active Raf-1 in the mitochondria restores antiapoptotic and leukemogenic potential of a transformation-deficient BCR/ABL mutant

The oncogenic BCR/ABL protein protects hematopoietic cells from apoptosis induced by growth factor deprivation, but the mechanisms are only partially understood. A BCR/ABL mutant lacking amino acids 176-426 in the BCR domain (p185DeltaBCR) failed to protect interleukin 3-deprived 32Dcl3 myeloid precursor cells from apoptosis, although it possessed tyrosine kinase activity and was capable of activating the Ras-Raf-MAP kinase pathway. Compared to p185 wild-type transfectants, p185DeltaBCR-transfected cells showed markedly reduced levels of Bcl-2 and expressed the hypophosphorylated, proapoptotic form of BAD. Bcl-2 expression in the mitochondrial fraction of p185DeltaBCR cells was also markedly diminished and mitochondrial RAF was undetectable. In p185DeltaBCR cells transfected with a mitochondria-targeted, constitutively active RAF (M-Raf) BAD was expressed in the hyperphosphorylated form and released from the mitochondria into the cytosol. p185DeltaBCR/M-Raf-transfected cells were completely resistant to apoptosis induced by growth factor deprivation in vitro. Moreover, constitutive expression of dominant-negative M-Raf (K375W) enhanced the susceptibility of 32Dcl3 cells expressing wild-type BCR/ABL to apoptosis. In severe combined immunodeficiency (SCID) mice, p185DeltaBCR/M-Raf double transfectants were leukemogenic, whereas cells expressing only p185DeltaBCR showed no leukemogenic potential. Together, these data support the existence of a BCR/ABL-dependent pathway that leads to expression of an active RAF in the mitochondria and promotes antiapoptotic and leukemia-inducing effects of BCR/ABL.     

Synovial cysts of the hips in seronegative arthritis

Calciphylaxis is a rare condition of widespread calcification of tissues and blood vessels with accompanying vascular thrombosis and ischemic necrosis. Most cases develop in association with hyperparathyroidism in patients with chronic renal failure. Pseudoxanthoma elasticum (PXE) is a hereditary condition of abnormal elastic tissue structure that leads to widespread abnormalities of the skin, retina, and visceral organs. Histologic changes of PXE have been observed as coincidental findings in several conditions such as following trauma to the skin manifest as isolated plaques often in scars. We observed histologic findings of PXE in a patient with chronic renal failure who developed fatal calciphylaxis. Complete evaluation failed to reveal evidence of systemic findings of PXE. Histologic changes of PXE may be seen in patients with calciphylaxis as a coincidental finding. Rapidly developing soft tissue calcification may lead to the expression of the characteristic histopathologic findings of PXE without evidence of classic clinical manifestations of PXE. Calciphylaxis should be added to the list of disorders that may lead to microscopic PXE-like changes.     

Cse1p is required for export of Srp1p/importin-alpha from the nucleus in Saccharomyces cerevisiae

In metazoan cells, the CAS protein has been shown to function as a recycling factor for the importin-alpha subunit of the classical nuclear localization signal receptor, exporting importin-alpha from the nucleus to allow its participation in multiple rounds of nuclear import. CAS is a member of a family of proteins that bear homology to the larger subunit of the nuclear localization signal receptor, importin-beta, and that are found in all eukaryotes from yeast to humans. Sequence similarity identifies the product of the Saccharomyces cerevisiae CSE1 gene as a potential CAS homologue. Here we present evidence that Cse1p is the functional homologue of CAS: Cse1p is required to prevent accumulation of Srp1p/importin-alpha in the nucleus, it localizes to the nuclear envelope in a pattern typical of nuclear transport receptors, and it associates in vivo with Srp1p in a nucleotide-specific manner. We show further that mutations in CSE1 and SRP1 have specific effects on their association and on the intracellular localization of Cse1p.     

Comparison of T2 lesion volume and magnetization transfer ratio histogram analysis and of atrophy and measures of lesion burden in patients with multiple sclerosis

A kinetic analysis of degradation of saturated oligoguluronates by poly(alpha-L-guluronate)lyase from Corynebacterium sp. ALY-1 strain was done. The saturated oligoguluronates were prepared by hydrolyzing poly alpha-1,4-L-guluronate from alginate with HCl, and then by gel filtration on a Bio-Gel P-6 column. The saturated pentaguluronate or above were rapidly degraded by the enzyme, while tetraguluronate was slowly degraded. From the dependency of the catalytic rate constant (kcat) on the degree of polymerization of substrates, the enzyme was found to have a subsite size corresponding to hexaguluronate units. The action pattern of the enzyme on hexaguluronate suggested that the catalytic site of the enzyme was matched to the linkage between the second and third uronic residue from the non-reducing end, since the substrate was mainly split into a unsaturated tetramer and a saturated dimer from a HPLC analysis.     

Management of bronchobiliary fistula as a late complication of hepatic resection

Bronchobiliary fistula is an uncommon but remarkable complication after hepatic resection. The case reported illustrates the clinical presentation and preferred initial management of these fistulae. A 61-year-old white male underwent two wedge resections for colorectal metastases to the liver with removal of a portion of the right diaphragm. Four years later, he developed obstructive jaundice secondary to tumor recurrence in the porta hepatis, which required endoscopic stent placement, radiation, and chemotherapy. Almost 2 years later, he developed frank biliptysis. Percutaneous transhepatic cholangiography (PTC) revealed occlusion of the common hepatic duct stent and a bronchobiliary fistula. With adequate reestablishment of common duct drainage, the patient rapidly improved and was discharged free of symptoms. Bronchobiliary fistulae are rare complications of hepatic resection that can present from days to years after operation. Endoscopic retrograde cholangiopancreatography and PTC are the diagnostic studies of choice and offer the possibility of therapeutic intervention. Although large series in the literature emphasize the surgical management of bronchobiliary fistulae, the reoperative procedures tend to be complicated, with a significant morbidity and mortality. Nonsurgical interventions via endoscopic retrograde cholangiopancreatography or PTC are more recently notably successful when resolution of a distal biliary obstruction is accomplished. Only after aggressive attempts at nonoperative, interventional techniques have failed should operative approaches be entertained.     

Mixed-dye staining method for protein detection in polyacrylamide gel electrophoresis using calconcarboxylic acid and rhodamine B

We have developed a new mixed-dye protein staining method that is simple, rapid, and sensitive. A freshly prepared mixture of calconcarboxylic acid (NN, 0.02%) and rhodamine B (RB, 0.04%) in 40% methanol/7% acetic acid, was used as a staining solution. RB acts as an auxiliary agent to inhibit the binding of NN to the gel matrix, reducing the background staining and therefore enhancing the protein staining by NN. This mixed-dye staining method reduces the total staining and destaining time to less than an hour, and increases the sensitivity to 25 ng of bovine serum albumin, which is greater than the 100 ng sensitivity limit of Coomassie Brilliant Blue R-250 (CBBR) staining.