Mysterious bruises.

A 69-year-old man presented with multiple spontaneous bruises in the past 2 weeks. Several large-sized hematomas were found on examination. The initial investigation revealed a prolonged activated partial thromboplastin time (aPTT) with normal platelet count and international normalized ratio. Further investigation revealed a low factor VIII activity secondary to presence of factor VIII inhibitor, making the diagnosis of acquired hemophilia A. Further work-up revealed that pernicious anemia was present and acted as an associated disease. After steroids therapy, his aPTT was normalized and the factor VIII inhibitor titer became undetectable. 2 months later, a relapse occurred and new hematomas appeared at his retropharyngeal space and left arm. His bleeding was controlled by administration of recombinant factor VIIa, and a combined therapy of intravenous steroids and rituximab was given to eradicate the inhibitor. The approach to workup of bleeding disorders as well as treatment of acquired hemophilia A are herein discussed.

Pyrroloquinoline quinone nutritional status alters lysine metabolism and modulates mitochondrial DNA content in the mouse and rat.

Pyrroloquinoline quinone (PQQ) added to purified diets devoid of PQQ improves indices of perinatal development in rats and mice. Herein, PQQ nutritional status and lysine metabolism are described, prompted by a report that PQQ functions as a vitamin-like enzymatic cofactor important in lysine metabolism (Nature 422 [2003] 832). Alternatively, we propose that PQQ influences lysine metabolism, but by mechanisms that more likely involve changes in mitochondrial content. PQQ deprivation in both rats and mice resulted in a decrease in mitochondrial content. In rats, alpha-aminoadipic acid (alphaAA), which is derived from alpha-aminoadipic semialdehyde (alphaAAS) and made from lysine in mitochondria, and the plasma levels of amino acids known to be oxidized in mitochondria (e.g., Thr, Ser, and Gly) were correlated with changes in the liver mitochondrial content of PQQ-deprived rats, but not PQQ-supplemented rats. In contrast, the levels of NAD dependent alpha-aminoadipate-delta-semialdehyde dehydrogenase (AASDH), a cytosolic enzyme important to alphaAA production from alphaAAS, was not influenced by PQQ dietary status. Moreover, the levels of U26 mRNA were not significantly changed even when diets differed markedly in PQQ and dietary lysine content. U26 mRNA levels were measured, because of U26's proposed, albeit questionable role as a PQQ-dependent enzyme involved in alphaAA formation.

Expression and functional study of estrogen receptor-related receptors in human prostatic cells and tissues.

Estrogen receptor-related receptors (ERRs; alpha, beta, gamma) are orphan nuclear receptors and constitutively active without binding to estrogen. Like estrogen receptors (ERs), ERRs bind to estrogen receptor elements and estrogen receptor element-related repeats. Growing evidence suggests that ERRs can cross-talk with ERs in different cell types via competition for DNA sites and coactivators. We hypothesize that ERRs might play regulatory roles in normal and neoplastic prostatic cells by sharing similar ER-mediated pathways or acting independently. In this study, we investigated mRNA and protein expression patterns of three ERR members in normal human prostate epithelial cells, established cell lines, cancer xenografts, and prostatic tissues. Additionally, effects of transient transfection of ERRs on prostatic cell proliferation and ER expression were also examined. RT-PCR showed that ERRalpha and ERRgamma transcripts were detected in most cell lines and xenografts, whereas ERRbeta was detected in normal epithelial cells and few immortalized cell lines but not in most cancer lines. Similar results were demonstrated in clinical prostatic specimens. Western blottings and immunohistochemistry confirmed similar expression patterns that ERR proteins were detected as nuclear proteins in epithelial cells, whereas their expressions became reduced or undetected in neoplastic prostatic cells. Transient transfection confirmed that ERRs were expressed in prostatic cells as nuclear proteins and transcriptionally active in the absence of estradiol. Transfection results showed that overexpression of ERRs inhibited cell proliferation and repressed ERalpha transcription in PC-3 cells. Our study shows that ERRs, which are coexpressed with ERs in prostatic cells, could regulate cell growth and modulate ER-mediated pathways via interference on ERalpha transcription in prostatic cells.

Small bowel perforation after radiotherapy for cervical carcinoma.

Radiotherapy is the treatment of choice for carcinoma of the uterine cervix. We report on a 62-year-old Chinese woman with cervical carcinoma, in whom a small bowel perforation developed 5 months after radiotherapy. Ten centimetres of small bowel, including the perforation site, were resected. No bowel adhesion was detected during the operation. The postoperative course was uneventful, and the patient was discharged home 7 days after surgery. Histological examination confirmed post-irradiation injury. The presenting complaints of patients with bowel perforation following radiotherapy vary, and signs of peritonitis may be absent. Emergency physicians must be alert for these complications in patients who have been treated with radiotherapy.

Positively charged residues at positions 12, 17, and 18 of glucagon ensure maximum biological potency.

Glucagon is a peptide hormone that plays a central role in the maintenance of normal circulating glucose levels. Structure-activity studies have previously demonstrated the importance of histidine at position 1 and the absolute requirement for aspartic acid at position 9 for transduction of the hormonal signal. Site-directed mutagenesis of the receptor protein identified Asp64 on the extracellular N-terminal tail to be crucial for the recognition function of the receptor. In addition, antibodies generated against aspartic acid-rich epitopes from the extracellular region competed effectively with glucagon for receptor sites, which suggested that negative charges may line the putative glucagon binding pocket in the receptor. These observations led to the idea that positively charged residues on the hormone may act as counterions to these sites. Based on these initial findings, we synthesized glucagon analogs in which basic residues at positions 12, 17, and 18 were replaced with neutral or acidic residues to examine the effect of altering the positive charge on those sites on binding and adenylyl cyclase activity. The results indicate that unlike N-terminal histidine, Lys12, Arg17, and Arg18 of glucagon have very large effects on receptor binding and transduction of the hormonal signal, although they are not absolutely critical. They contribute strongly to the stabilization of the binding interaction with the glucagon receptor that leads to maximum biological potency.

Circulating granulocyte and macrophage progenitor cells in primary and secondary myelofibrosis.

Patients with primary myelofibrosis (PMF) and myelofibrosis secondary to carcinoma (SMF) were compared with regard to circulating granulocyte macrophage progenitor cells (CFU-GM) using in vitro tissue culture techniques. Although increased numbers of CFU-GM had previously been well documented in PMF, few patients with the secondary variety had been studied. Our data indicate that there is an increase in circulating CFU-GM in patients with SMF but it is significantly lower than in those with PMF. It is suggested that in both conditions disruption of the marrow microvascular system results in a release of CFU-GM to the circulation. In PMF stem cell colonization of the spleen with its consequent myeloid metaplasia may be responsible for the additional increase in CFU-GM. The determination of CFU-GM numbers may provide additional data to help to distinguish PMF and SMF in atypical cases where the distinction is unclear.

Rapid Increase in UDP-Glucose during Early Wheat Embryo Germination.

The cellular content of UDP-glucose in isolated wheat (Triticum aestivum L.) embryo increases 8-fold during the first 40 minutes of imbibition. An additional 3-fold increase in the amount of UDP-glucose was observed in the next 5 hours of germination. This communication also describes a unique, quantitative method to achieve a high sensitivity in a direct determination of UDP-glucose with Na [(32)P]pyrophosphate and UDP-glucose pyrophosphorylase. The sensitivity of the assay for UDP-glucose is 10 picomoles.

Stimulation of the protein synthetic process by adenosine 3':5'-monophosphate and hexose phosphates in gel-filtered rabbit reticulocyte lysates.

The addition of 0.167 to 4.0 mM cAMP to gel-filtered rabbit reticulocyte lysates stimulates the initial rate and the extent of polypeptide synthesis. The stimulation is at the initiation step of polypeptide synthesis as measured by the (i) increased dipeptide, methionyl-valine, accumulation in the presence of the specific initiation inhibitor, pactamycin, and (ii) increased formation of the 40 S and 80 S initiation complex when gel-filtered lysates are incubated with [35S]Met-tRNAFMet. Furthermore, a synergistic stimulation of protein synthesis is observed when cAMP and hexose phosphates (which alone elicit a 1.8-fold stimulation of protein synthesis) are added simultaneously to gel-filtered rabbit reticulocyte lysates. These results indicate that cAMP and hexose phosphates are both essential to maintain the high rate of initiation.

Stimulation and inhibition of the protein synthetic process by NAD+ in lysed rabbit reticulocytes.

NAD+ at 0.16 mM stimulates the initiation step of the protein synthetic process in lysed rabbit reticulocytes. This conclusion is based on the stimulation of (i) the transfer of formylmethionine from f[35S]Met-tRNAfMet into polypeptide, (ii) the accumulation of the initial dipeptide, methionylvaline, in the presence of pactamycin, and (iii) the formation of the 40 S initiation complex. The effect of NAD+ changes from a stimulatory role on protein synthesis to an inhibitory role at concentrations greater than 0.16 mM. At 4.0 mM NAD+, protein synthesis is inhibited. This has been demonstrated experimentally by using the same three assays described above. In addition, 4.0 mM NAD+ inhibits MettRNAfMet.initiation factor.GTP ternary complex formation. The elongation and termination steps of polypeptide synthesis are not affected by 0.16 to 4.0 mM NAD+. The data presented clearly show that the stimulatory activity of 0.16 mM NAD+ and the inhibitory activity of 4.0 mM NAD+ affects the initiation step of the protein synthetic process in lysed rabbit reticulocytes.