Faecal calprotectin and faecal occult blood tests in the diagnosis of colorectal carcinoma and adenoma

BACKGROUND AND AIMS

Testing for faecal occult blood has become an accepted technique of non-invasive screening for colorectal neoplasia but lack of sensitivity remains a problem. The aim of this study was to compare the sensitivity and specificity of faecal calprotectin and faecal occult blood in patients with colorectal cancer and colonic polyps.

METHODS

Faecal calprotectin and occult blood were assessed in 62 patients with colorectal carcinoma and 233 patients referred for colonoscopy. The range of normality for faecal calprotectin (0.5-10.5 mg/l) was determined from 96 healthy subjects.

RESULTS

Median faecal calprotectin concentration in the 62 patients with colorectal carcinoma (101 mg/l, 95% confidence interval (CI) 57-133) differed significantly from normal (2.3 mg/l, 95% CI 1.6-5.0) with 90% of patients having elevated levels (normal <10 mg/l) whereas only 36/62 (58%) had positive faecal occult bloods. There was no significant difference in faecal calprotectin levels when considering location or Dukes' staging of tumour. Percentage positivity of faecal occult bloods was significantly higher for Dukes' stage C and D cancers compared with Dukes' A and B. In the colonoscopy group, 29 patients with adenomatous polyps were detected in whom the median faecal calprotectin was 12 mg/l (95% CI 2.9-32). Sensitivity for detection of adenomatous polyps was 55% using the calprotectin method and 10% using faecal occult blood testing. The overall sensitivity and specificity of calprotectin for colorectal cancer and adenomatous polyps as a combined group was 79% and 72%, respectively, compared with a sensitivity and specificity of faecal occult blood of 43% and 92%.

CONCLUSIONS

Faecal calprotectin is a simple and sensitive non-invasive marker of colorectal cancer and adenomatous polyps. It is more sensitive than faecal occult blood tests for detection of colorectal neoplasia at the cost of a somewhat lower specificity.

Photic entrainment of the circadian clock: from Drosophila to mammals

Entrainment is as fundamental to an organism's circadian timing as are the molecular mechanisms involved in the functioning of the intracellular clock oscillator. In nature, one of the principle, although not the only, circadian entraining stimulus (Zeitgeber) is provided by the daily light--dark cycles. In animals, the visual processing apparatus alone is inadequate to accomplish the task of transducing circadian photic signals to the clockwork machinery. In fact, it is ever more appreciated by circadian biologists that organisms as divergent as plants and mammals have evolved a wonderfully complex array of partly redundant specializations which can guarantee the precise alignment of biological and environmental time. Research in circadian biology is cruising at such a rate that attempts to review the state of the art can only hope, at best, to provide a snapshot of the speeding cruiser from its wake. This paper will hopefully provide a reasonably sharp portrayal of what is at hand.

Monoclonal antibody identifies a distinctive epitope expressed by human multiple myeloma cells

Employing a technology called differential immunization for antigen and antibody discovery (DIAAD), we aimed to generate monoclonal antibodies (mAbs) specific to human multiple myeloma (MM) cells. The fundamental principles of DIAAD rely on the induction of high zone tolerance to the "wild type" (normal) antigen. followed by immunization with the modified (diseased) antigen. Because chronic myelogenic leukemia (CML) cells are derived from a lineage closely related to MM, we immunized mice by contrasting a pool of MM cells with CML cells. Monoclonal antibody VAC69 reacted exclusively with MM cells, identifying a membrane molecule composed of a single-chain glycoprotein with a molecular weight of 78-120 kd. This antigen exhibited narrow tissue specificity and was not found on human cancers such as prostate, breast, or cervical carcinoma; leukemia; or lymphoma, nor was it seen on normal human peripheral lymphocytes or on Epstein-Barr virus-transformed B-cell lines. By immunohistochemistry, mAb VAC69 showed no binding to antigens expressed on normal human ovary, breast, prostate, lung or colon tissue, nor did it bind to human breast or prostate cancer. Conversely, mAb VAC69 bound strongly to human MM, although showing only slight binding to histiocytes or inflamed cells in human lymph nodes and human tumors of the colon, lung, and ovary. Monoclonal antibody VAC69 also triggered cancer-specific cytotoxicity in vitro (in the presence of complement) as well as in vivo using a sever combined immunodeficiency model transplanted with human MM. Further studies showed the ability of mAb VAC69 to be specifically internalized by human MM cells, indicating its potential use for therapeutic intervention in MM by delivering drugs into cancer cells.

Safety and efficacy of preoperative administration of meloxicam, compared with that of ketoprofen and butorphanol in dogs undergoing abdominal surgery

OBJECTIVE

To compare the safety and efficacy of preoperative administration of meloxicam with that of ketoprofen and butorphanol in dogs undergoing abdominal surgery.

ANIMALS

36 dogs undergoing laparotomy, splenectomy, or cystotomy.

PROCEDURE

Dogs were randomly assigned to 1 of 3 groups. In the first part of the study, dogs were given a single dose of meloxicam, ketoprofen, or a placebo, and buccal mucosal bleeding times were measured. In the second part of the study, dogs were given meloxicam, ketoprofen, or butorphanol prior to surgery. Dogs in the butorphanol group received a second dose immediately after surgery. Pain scores (1 to 10) were assigned hourly for 20 hours after surgery and used to determine an overall efficacy score for each dog. Dogs with a pain score > or =3 were given oxymorphone for pain. Dogs were euthanatized 8 days after surgery, and gross and histologic examinations of the liver, kidneys, and gastrointestinal tract were conducted.

RESULTS

Overall efficacy was rated as good or excellent in 9 of the 12 dogs that received meloxicam, compared with 9 of the 12 dogs that received ketoprofen and only 1 of the 12 dogs that received butorphanol. No clinically important hematologic, biochemical, or pathologic abnormalities were detected.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that preoperative administration of meloxicam is a safe and effective method of controlling postoperative pain for 20 hours in dogs undergoing abdominal surgery; the analgesic effects of meloxicam were comparable to those of ketoprofen and superior to those of butorphanol.

Elevated and altered expression of the multifunctional DNA base excision repair and redox enzyme Ape1/ref-1 in prostate cancer

The DNA base excision repair pathway is responsible for the repair of cellular alkylation and oxidative DNA damage. A crucial step in the BER pathway involves the cleavage of baseless sites in DNA by an apurinic/apyrimidinic or baseless (AP) endonuclease (Ape1/ref-1), which is a multifunctional enzyme that acts not only as an AP endonuclease but also as a redox-modifying factor for a variety of transcription factors including Fos, Jun, paired box containing genes (PAX), nuclear factor-kappaB, hypoxia-inducible factor alpha (HIF-1alpha), HIF-like factor (HLF), p53, and others. The expression of Ape1/ref-1 in prostate has not been characterized previously. Ape1/ref-1 nuclear immunohistochemistry levels, scored for intensity as 1+, 2+, or 3+, were 91, 3, and 6% in benign hypertrophy (BPH), 0, 42, and 58% in prostatic intraepithelial neoplasia (PIN) and 3, 30, and 67% in prostate cancer, respectively, clearly showing an increase in Ape1/ref-1 nuclear staining in the PIN and cancer compared with BPH. Furthermore, the level of cytoplasmic staining of Ape1/ref-1 in cancer and PIN were elevated (42 and 36%, respectively) compared with BPH (5%). There was no correlation with prostate-specific antigen values or doubling times to Ape1/ref-1 levels. In conclusion, we have demonstrated that Ape1/ref-1 is dramatically elevated in prostate cancer, the level of staining of Ape1/ref-1 increases from low in BPH to intense in PIN and cancer, and there is an increase in the amount of Ape1/ref-1 in the cytoplasm of PIN and cancer compared with BPH. Given these results, we conclude that Ape1/ref-1 may be a diagnostic marker for early prostate cancer and play a role, through its repair, redox, or both functions, in the physiology of the early development of prostate cancer.

A simple method for assessing intestinal inflammation in Crohn's disease

BACKGROUND AND AIMS

Assessing the presence and degree of intestinal inflammation objectively, simply, and reliably is a significant problem in gastroenterology. We assessed faecal excretion of calprotectin, a stable neutrophil specific marker, as an index of intestinal inflammation and its potential use as a screening test to discriminate between patients with Crohn's disease and those with irritable bowel syndrome.

METHODS

The validity of faecal calprotectin as a marker of intestinal inflammation was assessed in 22 patients with Crohn's disease (35 studies) by comparing faecal excretions and concentrations using four day faecal excretion of (111)indium white cells. A cross sectional study assessed the sensitivity of faecal calprotectin concentration for the detection of established Crohn's disease (n=116). A prospective study assessed the value of faecal calprotectin in discriminating between patients with Crohn's disease and irritable bowel syndrome in 220 patients referred to a gastroenterology clinic.

RESULTS

Four day faecal excretion of (111)indium (median 8.7%; 95% confidence interval (CI) 7-17%; normal <1.0%) correlated significantly (p<0.0001) with daily (median ranged from 39 to 47 mg; normal <3 mg; r=0.76-0.82) and four day faecal calprotectin excretion (median 101 mg; 95% CI 45-168 mg; normal <11 mg; r=0.80) and single stool calprotectin concentrations (median 118 mg/l; 95% CI 36-175 mg/l; normal <10 mg/l; r=0.70) in patients with Crohn's disease. The cross sectional study showed a sensitivity of 96% for calprotectin in discriminating between normal subjects (2 mg/l; 95% CI 2-3 mg/l) and those with Crohn's disease (91 mg/l; 95% CI 59-105 mg/l). With a cut off point of 30 mg/l faecal calprotectin has 100% sensitivity and 97% specificity in discriminating between active Crohn's disease and irritable bowel syndrome.

CONCLUSION

The calprotectin method may be a useful adjuvant for discriminating between patients with Crohn's disease and irritable bowel syndrome.

Predicting species diversity in tropical forests

A fundamental question in ecology is how many species occur within a given area. Despite the complexity and diversity of different ecosystems, there exists a surprisingly simple, approximate answer: the number of species is proportional to the size of the area raised to some exponent. The exponent often turns out to be roughly 1/4. This power law can be derived from assumptions about the relative abundances of species or from notions of self-similarity. Here we analyze the largest existing data set of location-mapped species: over one million, individually identified trees from five tropical forests on three continents. Although the power law is a reasonable, zeroth-order approximation of our data, we find consistent deviations from it on all spatial scales. Furthermore, tropical forests are not self-similar at areas Collapse

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Children's use of PCA following spinal fusion

PURPOSE

The purpose of this study was to examine the effectiveness of patient-controlled analgesia (PCA) in relieving postoperative pain for children and adolescents following spinal fusion.

DESIGN/SAMPLE

A one-group, descriptive design was used with a convenience sample of 93 children (ages 8 to 21 years) who had undergone spinal fusion over a 2-year period.

METHODS

All of the patients were using PCA postoperatively with morphine sulfate, the most common opioid analgesic prescribed for use in the infusion pump. Data were collected for the first 4 postoperative days on four outcome variables: use of PCA, self-report of pain, observed pain-related behaviors, and satisfaction with PCA.

FINDINGS

Despite aggressive pain management, findings showed that neither children's pain nor their analgesic use diminished significantly over time. Children continued to report moderate-to-severe pain over the 4-day measurement period. Likewise, children reported their satisfaction with PCA for pain relieve as "fair" to "good."

CONCLUSION

The use of high technology and aggressive pharmacologic treatment alone may not be adequate for managing severe pain following spinal fusion. As proposed by the Gate Control Theory, pain stimuli produce not only physiologic, but also psychologic and emotional responses. Relief for severe pain, therefore, may require multidimensional therapies that include nonpharmacologic approaches together with precise titration of available pharmacologic agents.

Comparison of the intestinal toxicity of celecoxib, a selective COX-2 inhibitor, and indomethacin in the experimental rat

BACKGROUND

It is suggested that the gastrointestinal toxicity of conventional non-steroid anti-inflammatory drugs (NSAIDs) is due to a 'topical' effect in addition to inhibition of the mucosal constitutive cyclo-oxygenase-1 (COX-1) enzyme. COX-2 selective inhibitors have been shown to have excellent gastrointestinal tolerability, but it is not known whether this is due to their selectivity and/or a lack of a 'topical' effect. We assessed the effects of celecoxib (a highly selective COX-2 inhibitor) on key pathophysiologic events in NSAID enteropathy.

METHODS

The 'topical' effects of indomethacin and celecoxib were assessed in vitro (coupled mitochondrial respiration) and in vivo (mitochondrial electron microscopy) and the consequences by study of intestinal permeability (51-Cr-labelled ethylenediamine-tetraacetic acid urinary excretion) and inflammation. We also assessed intestinal prostanoid levels (prostaglandin E, PGE) and the propensity of the drugs to induce intestinal ulcers.

RESULTS

Indomethacin uncoupled mitochondrial oxidative phosphorylation in vitro and in vivo, caused a significant (P < 0.0001) increase in intestinal permeability, caused mucosal inflammation and a 90% decline in intestinal PGE levels, and was associated with multiple small intestinal ulcers. Celecoxib caused no significant increase in any of these parameters, did not decrease intestinal PGE levels, and caused no intestinal ulcers.

CONCLUSIONS

The intestinal tolerability of celecoxib appears to be due to a combination of the absence of a 'topical' damaging effect and selective COX inhibition.

Uncoupling of intestinal mitochondrial oxidative phosphorylation and inhibition of cyclooxygenase are required for the development of NSAID-enteropathy in the rat

BACKGROUND

The pathogenesis of NSAID-induced gastrointestinal damage is believed to involve a nonprostaglandin dependent effect as well as prostaglandin dependent effects. One suggestion is that the nonprostaglandin mechanism involves uncoupling of mitochondrial oxidative phosphorylation.

AIMS

To assess the role of uncoupling of mitochondrial oxidative phosphorylation in the pathogenesis of small intestinal damage in the rat.

METHODS

We compared key pathophysiologic events in the small bowel following (i) dinitrophenol, an uncoupling agent (ii) parenteral aspirin, to inhibit cyclooxygenase without causing a 'topical' effect and (iii) the two together, using (iv) indomethacin as a positive control.

RESULTS

Dinitrophenol altered intestinal mitochondrial morphology, increased intestinal permeability and caused inflammation without affecting gastric permeability or intestinal prostanoid levels. Parenteral aspirin decreased mucosal prostanoids without affecting intestinal mitochondria in vivo, gastric or intestinal permeability. Aspirin caused no inflammation or ulcers. When dinitrophenol and aspirin were given together the changes in intestinal mitochondrial morphology, permeability, inflammation and prostanoid levels and the macro- and microscopic appearances of intestinal ulcers were similar to indomethacin.

CONCLUSIONS

These studies allow dissociation of the contribution and consequences of uncoupling of mitochondrial oxidative phosphorylation and cyclooxygenase inhibition in the pathophysiology of NSAID enteropathy. While uncoupling of enterocyte mitochondrial oxidative phosphorylation leads to increased intestinal permeability and low grade inflammation, concurrent decreases in mucosal prostanoids appear to be important in the development of ulcers.

Influence of acebutolol and metoprolol on cardiac output and regional blood flow in rats

Beta-adrenoceptor blocking drugs are widely used as effective antihypertensive and antianginal agents. We have determined the effect of beta-blockade in the rat to ascertain whether there are differences between metoprolol (MET) and acebutolol (AC) with respect to regional blood flow (RBF). Both AC and MET were administered as a single or multiple intravenous (iv) doses in Sprague-Dawley rats. Microspheres labelled with (85)Sr and (141)Ce were used to measure cardiac output (CO) and RBF before and after drug administration. CO and RBF were measured 1 and 10 min after the i.v. administration of AC (30 mg/kg) and MET (10 mg/kg). After acute administration of MET, CO decreased by 65% and 31% after 1 and 10 min measurements, respectively. These values were 54% and 28% for AC as compared with baseline values. After chronic administration of either AC or MET, however, there were no significant reductions in CO as compared with saline. Both MET and AC significantly reduced RBF in most organs either after 1 or 10 min measurements when compared with the baseline values. It is concluded that both AC and MET reduced CO and RBF after acute administration. The CO and RBF however, returned to normal after chronic administration.

Adjuvant bleomycin, etoposide and cisplatin in pathological stage II non-seminomatous testicular cancer. the Indiana University experience

Two cycles of bleomycin, etoposide, and cisplatin (BEP) were evaluated as adjuvant chemotherapy for patients with pathological stage II non-seminomatous germ cell tumours. Between 1985 and 1995, 86 patients with pathological stage II non-seminomatous testicular cancer were treated with two cycles of BEP. At retroperitoneal lymph node dissection (RPLND) 49 patients (57%) had pathological stage II(A) (microscopic nodal metastases) and 37 (43%) had stage II(B) (gross nodal metastases). After RPLND, the patients received bleomycin, 30 units weekly for 8 weeks, etoposide (100 mg/m(2)) and cisplatin (20 mg/m(2)) each for 5 days every 28 days for two cycles as adjuvant chemotherapy. 4 patients were lost to follow-up. 10 patients (12%) developed granulocytopenic fever during their chemotherapy. Of the 82 evaluable patients all remained with no evidence of disease except for a single patient with a cervical nodal relapse of teratoma. This was resected and he remains disease free. Median follow-up has been 85 months (range: 42-173 months). In patients with fully resected stage II non-seminomatous germ cell tumour, two cycles of BEP were almost universally effective in preventing relapse.

Hepatic resection of metastatic testicular carcinoma: a further update

BACKGROUND

The goal of this study was to update the multidisciplinary review of patients who underwent resection of hepatic metastases of nonseminomatous germ cell testicular carcinoma at the Indiana University Medical Center.

METHODS

The study involved retrospective chart review for 57 patients who underwent hepatic resection for treatment of metastatic nonseminomatous testicular carcinoma between June 1974 and May 1996. Patients were categorized according to the worst postchemotherapy pathologic diagnosis.

RESULTS

Chemotherapy has been highly effective in curing testicular carcinoma. However, even with platinum-based chemotherapy, one-third of patients either do not achieve complete cures or experience relapses. Since 1965, only 57 of the 2219 patients who underwent postchemotherapy retroperitoneal lymph node dissections for treatment of testicular carcinoma at our center underwent hepatic resection for treatment of metastatic disease. Because teratomas have the propensity to degenerate into sarcomas and can cause symptoms resulting from compression, these lesions must be resected to achieve cures. In addition, the only chance for survival for patients with active disease but normal serum marker levels is with complete resection of the tumor burden.

CONCLUSIONS

We conclude that hepatic resection for treatment of metastatic testicular carcinoma is safe and efficacious for all patients except those with elevated marker levels after preoperative chemotherapy.

High prevalence of NSAID enteropathy as shown by a simple faecal test

BACKGROUND

The diagnosis of non-steroidal anti-inflammatory drug (NSAID) induced enteropathy is difficult, requiring enteroscopy or the use of four day faecal excretion of (111)In labelled white cells.

AIMS

To assess faecal calprotectin (a non-degraded neutrophil cytosolic protein) as a method for diagnosing NSAID enteropathy.

METHODS

Single stool faecal calprotectin concentrations were compared with the four day faecal excretion of (111)In labelled white cells in 47 patients taking NSAIDs. The prevalence and severity of NSAID enteropathy was assessed using this method in 312 patients (192 with rheumatoid arthritis, 65 with osteoarthritis, 55 with other conditions) taking 18 different NSAIDs.

RESULTS

The four day faecal excretion of (111)In white cells correlated significantly with faecal calprotectin concentrations. In the group of 312 patients on NSAIDs faecal calprotectin concentrations were significantly higher than in controls, the prevalence of NSAID enteropathy being 44%. The prevalence and severity of NSAID enteropathy was independent of the particular type or dose of NSAID being taken or other patient variables.

CONCLUSIONS

Assay of faecal calprotectin provides a simple practical method for diagnosing NSAID enteropathy in man. Forty four per cent of patients receiving these drugs had NSAID induced enteropathy when assessed by this technique; 20% of these had comparable levels of inflammation to that previously reported in patients with inflammatory bowel disease.

A long-term, controlled-outcome analysis of in utero versus neonatal cleft lip repair using an ovine model

Successful open repair of a cleft lip in utero has the advantage of scarless wound healing in the fetus. Unfortunately, no long-term outcome studies have been performed to evaluate the efficacy of these repairs. Moreover, no study to date has compared the long-term results of an in utero cleft lip repair to a similar, control-matched, newborn cleft repair. This study was performed to evaluate the 9-month outcome of in utero cleft lip surgery compared with an identical cleft lip repair performed on infant lambs. In utero epithelialized cleft lips were created through an open hysterotomy in sixteen 65-day-old fetal lambs (term = 140 days) using methods described by Longaker et al. Eight of 16 animals underwent subsequent in utero repair of these clefts at 90 days gestational age. The repair of the remaining eight animals was delayed until 1 week postpartum. At 9 months, the animals were analyzed for changes in lip contour and for the degree of scarring by hematoxylin and eosin and Masson's trichrome collagen staining. Two animals in each group died from preterm labor. Of the animals that survived to term, all repaired lips had some degree of abnormality postoperatively. One of six lips repaired in utero dehisced before delivery. Three of six neonatal repairs dehisced in the first postoperative month. In the remaining animals with intact lip repairs, the vertical lip height on the repaired side was an average of 9 to 12 mm shorter than the normal lip in both the in utero and neonatally repaired animals. Phenotypically, the postnatally repaired animals had more lip distortion and visible notching. Histologically, the in utero repair was scarless and the neonatal repairs had scar throughout the entire vertical height of the lip with an associated loss of hair in this region. Maxillary growth was also evaluated. There was no inhibition of maxillary growth in the animals that underwent in utero cleft lip repair. However, in the neonatal repair group, significant maxillary retrusion was evident. Compared with the cleft side of the maxilla, horizontal growth was decreased by 11 percent (p = 0.01). Compared with the intrauterine repair group, there was a 17-percent decrease in horizontal maxillary width (p = 0.01). Straight-line in utero repair of a cleft lip produces a better long-term result in terms of maxillary growth than a similar repair performed postnatally in the ovine model. There was no diminution in maxillary growth in the animals treated in utero. Histologically, in utero repair of clefts was indeed scarless. However, both lip repairs produced lips that were significantly shorter than their contralateral noncleft sides. This degree of lip shortening would require a secondary lip revision, thereby defeating the purpose of performing an intrauterine repair. Comparisons now need to be made between in utero and neonatal repairs using a Millard-type rotation advancement technique before intrauterine treatment can be considered to be more beneficial than our current treatment modalities.

Gene therapy for canine alpha-L-iduronidase deficiency: in utero adoptive transfer of genetically corrected hematopoietic progenitors results in engraftment but not amelioration of disease

Canine alpha-L-iduronidase (iduronidase) deficiency is a model of the human lysosomal storage disorder mucopolysaccharidosis type I (MPS I). We used this canine model to evaluate the therapeutic potential of hematopoietic stem cell (HSC) gene therapy for enzyme deficiencies. In previous studies, iduronidase-deficient dogs infused with autologous marrow cells genetically modified to express iduronidase had long-term engraftment with provirally marked cells, but there was no evidence of proviral iduronidase expression or clinical improvement. The presence of humoral and cellular immune responses against iduronidase apparently abrogated the therapeutic potential of HSC gene therapy in these experiments. To evaluate HSC gene therapy for canine MPS I in the absence of a confounding immune response, we have now performed in utero adoptive transfer of iduronidase-transduced MPS I marrow cells into preimmune fetal pups. In three separate experiments, 17 midgestation fetal pups were injected with 0.5-1.5 x 10(7) normal or MPS I allogeneic long-term marrow culture (LTMC) cells transduced with neo(r)- or iduronidase-containing retroviral vectors. Nine normal and three MPS I pups survived the neonatal period and demonstrated engraftment of provirally marked progenitors at levels of up to 12% for up to 12 months. However, the proportion of provirally marked circulating leukocytes was approximately 1%. Neither iduronidase enzyme nor proviral-specific transcripts were detected in blood or marrow leukocytes of any MPS I dog. Humoral immune responses to iduronidase were not detected in neonates, even after "boosting" with autologous iduronidase-transduced LTMC cells. All MPS I dogs died at 8-11 months of age from complications of MPS I disease with no evidence of amelioration of MPS I disease. Our results suggest that iduronidase-transduced primitive hematopoietic progenitors can engraft in fetal recipients, contribute to hematopoiesis, and induce immunologic nonresponsiveness to iduronidase in MPS I dogs. However, the therapeutic potential of HSC gene transfer in this model of iduronidase deficiency appears to be limited by poor maintenance of proviral iduronidase gene expression and relatively low levels of genetically corrected circulating leukocytes.

Signaling domains of the beta c chain of the GM-CSF/IL-3/IL-5 receptor

The granulocyte/macrophage colony-stimulating factor (GM-CSF)/interleukin-3 (IL-3)/IL-5 receptors are a family of heterodimeric transmembrane proteins expressed by myeloid lineage cells. Each receptor has a unique ligand-binding alpha chain and they share a common beta chain (beta c chain). Binding of GM-CSF activates at least one receptor-associated tyrosine kinase, JAK2, and rapidly induces tyrosine phosphorylation of the GMR beta c chain (GMR beta), but not the GMR alpha chain (GMR alpha). Mutation of each of the 8 tyrosine residues in the cytoplasmic domain of the human GMR beta to phenylalanine (GMR beta-F8) reduced tyrosine phosphorylation of GMR beta, SHP2 and SHC, but not JAK2 or STAT5. Interestingly, GMR beta-F8 was still capable of inducing at least short-term proliferation and enhancing viability. The role of each individual tyrosine residue was explored by replacing each mutated phenylalanine with the wild-type tyrosine residue. Tyrosine 577 was found to be sufficient to regenerate GM-CSF-dependent phosphorylation of SHC, and any of Y577, Y612, or Y695 were sufficient to regenerate GM-CSF-inducible phosphorylation of SHP2. Next, a series of four internal deletion mutants were generated, which deleted small sections from aa 518 to 626. One of these, deleting residues 566-589 was profoundly defective in signaling and supporting viability, and may identify an important viability signaling domain for this receptor family. Overall, these results indicate that GMR beta tyrosine residues are not necessary for activation of the JAK/STAT pathway, or for proliferation, viability, or adhesion signaling in Ba/F3 cells, although tyrosine residues significantly affect the magnitude of the response. However, internal deletion mutant studies identify critical domains for viability and proliferation.

Regulation of mammalian circadian behavior by non-rod, non-cone, ocular photoreceptors

Circadian rhythms of mammals are entrained by light to follow the daily solar cycle (photoentrainment). To determine whether retinal rods and cones are required for this response, the effects of light on the regulation of circadian wheel-running behavior were examined in mice lacking these photoreceptors. Mice without cones (cl) or without both rods and cones (rdta/cl) showed unattenuated phase-shifting responses to light. Removal of the eyes abolishes this behavior. Thus, neither rods nor cones are required for photoentrainment, and the murine eye contains additional photoreceptors that regulate the circadian clock.

Genetically corrected autologous stem cells engraft, but host immune responses limit their utility in canine alpha-L-iduronidase deficiency

Canine alpha-L-iduronidase (alpha-ID) deficiency, a model of the human storage disorder mucopolysaccharidosis type I (MPS I), is an ideal system in which to evaluate the clinical benefit of genetically corrected hematopoietic stem cells. We performed adoptive transfer of genetically corrected autologous hematopoietic cells in dogs with alpha-ID deficiency. Large volume marrow collections were performed on five alpha-ID-deficient dogs. Marrow mononuclear cells in long-term marrow cultures (LTMCs) were exposed on three occasions during 3 weeks of culture to retroviral vectors bearing the normal canine alpha-ID cDNA. Transduced LTMC cells from deficient dogs expressed enzymatically active alpha-ID at 10 to 200 times the levels seen in normal dogs. An average of 32% of LTMC-derived clonogenic hematopoietic cells were provirus positive by polymerase chain reaction and about half of these expressed alpha-ID. Approximately 10(7) autologous gene-modified LTMC cells/kg were infused into nonmyeloablated recipients. Proviral DNA was detected in up to 10% of individual marrow-derived hematopoietic colonies and in 0.01% to 1% of blood and marrow leukocytes at up to 2 to 3 years postinfusion. Despite good evidence for engraftment of provirally marked cells, neither alpha-ID enzyme nor alpha-ID transcripts were detected in any dog. We evaluated immune responses against alpha-ID and transduced cells. Humoral responses to alpha-ID and serum components of the culture media (fetal bovine and horse sera and bovine serum albumin) were identified by enzyme-linked immunosorbent assay. Cellular immune responses to autologous alpha-ID but not neo(r) transduced cells were demonstrated by lymphocyte proliferation assays. To abrogate potential immune phenomena, four affected dogs received posttransplant cyclosporine A. Whereas immune responses were dampened in these dogs, alpha-ID activity remained undetectable. In none of the dogs engrafted with genetically corrected cells was there evidence for clinical improvement. Our data suggest that, whereas the alpha-ID cDNA may be transferred and maintained in approximately 5% of hematopoietic progenitors, the potential of this approach appears limited by the levels of provirally derived enzyme that are expressed in vivo and by the host's response to cultured and transduced hematopoietic cells expressing foreign proteins.

Clinical validation of the Helikit: a 13C urea breath test used for the diagnosis of Helicobacter pylori infection

OBJECTIVE

To assess the clinical performance of the Helikit, a 13C urea breath test, in the diagnosis of Helicobacter pylori infection.

METHODS

A total of 205 participants were assessed in Canada and Korea for H. pylori infection status by endoscopy, or a combination of IgG ELISA and CLO test, as well as by the Helikit. The Helikit contains 75 mg of 13C urea as well as citric acid, flavor enhancers and stabilizers in a single plastic cup. The powder is dissolved in 75 mL of water for oral administration. No extra mixing or dilution steps are required.

RESULTS

Using the biopsy-derived data as the gold standard the Helikit displayed a clinical sensitivity of 93.5% (95% confidence interval 88.5 to 98.5%) and a clinical specificity of 97.3% (94.3 to 100%). An overall diagnostic efficiency of 95.6% (92.8 to 98.4%) was obtained. No statistically significant difference in the performance characteristics was found between Korea and Canada. No significant adverse events were noted.

CONCLUSIONS

The Helikit offers an easy, safe and accurate approach to the diagnosis of H. pylori infection.

An Arabidopsis mutant with deregulated ABA gene expression: implications for negative regulator function

The physiological acclimation of plants to osmotic stresses involves a complex programme of gene regulation. In one signalling pathway, elevated levels of abscisic acid (ABA) activate a subset of stress genes. Because ABA responses lack a definable morphological phenotype, we have screened for mutants that exhibit deregulated ABA-responsive gene expression. To monitor this ABA response, a line of Arabidopsis thaliana carrying a transgene composed of the ABA-responsive Arabidopsis kin2 promoter fused to the coding sequence for the firefly luciferase gene, kin2::luc, was generated. Patterns of ABA-responsive luciferase activity were monitored by photon counting. In contrast to wild-type plants which display a transient activation of kin2::luc, an ABA deregulated gene expression mutant (ade1) exhibits both sustained and enhanced levels of transgene activity. Levels of kin2, cor47 and rab18 expression in ade1 plants are also enhanced and prolonged indicating that the molecular mechanism(s) altered in ade1 plants affects the regulation of other ABA-responsive genes. The mutant phenotype is specific for the ABA response as cold-inducible kin2 expression is unaltered in ade1 plants. Genetic analyses indicate that the ade1 mutant is a monogenic recessive trait. A role for negative regulator function in ABA signalling is discussed.

Enantiomers of flurbiprofen can distinguish key pathophysiological steps of NSAID enteropathy in the rat

BACKGROUND

Non-steroidal anti-inflammatory drugs (NSAIDs) cause gastrointestinal damage by a non-prostaglandin (PG) dependent "topical" action and by inhibiting cyclooxygenase.

AIMS

To discriminate between these two effects by studying some key pathophysiological steps in NSAID enteropathy following administration of (R)- and (S)-flurbiprofen, the racemic mixture, and an uncoupler, dinitrophenol.

METHODS

The effects of dinitrophenol, racemic, (R)-, and (S)-flurbiprofen on mitochondria were assessed in vitro and on key pathophysiological features of small intestinal damage in vivo (ultrastructure by electron microscopy, mucosal prostanoid concentrations, intestinal permeability, inflammation, and ulcer count) in rats.

RESULTS

All the drugs uncoupled mitochondrial oxidative phosphorylation in vitro, caused mitochondrial damage in vivo, and increased intestinal permeability. Dinitrophenol and (R)-flurbiprofen caused no significant decreases in mucosal prostanoid concentrations (apart from a decrease in thromboxane (TX) B2 concentrations following (R)-flurbiprofen) while racemic and (S)- flurbiprofen reduced mucosal prostanoids significantly (PGE, TXB2, and 6-keto-PGF1alpha concentrations by 73-95%). Intestinal inflammation was significantly greater following administration of (S)-flurbiprofen and racemate than with dinitrophenol and (R)-flurbiprofen. No small intestinal ulcers were found following dinitrophenol or (R)-flurbiprofen while both racemic and (S)-flurbiprofen caused numerous ulcers.

CONCLUSIONS

Dinitrophenol and (R)-flurbiprofen show similarities in their actions to uncouple mitochondrial oxidative phosphorylation in vitro, alter mitochondrial morphology in vivo, increase intestinal permeability, and cause mild inflammation without ulcers. Concurrent severe decreases in mucosal prostanoids seem to be the driving force for the development of severe inflammation and ulcers.

The in utero repair of Tessier number 7 lateral facial clefts created by amniotic band-like compression

The purpose of this study was to determine the effectiveness of intrauterine reconstruction of lateral facial clefts caused by surgically simulated amniotic band compression. The authors hypothesized that intrauterine lysis of these bands could: 1) prevent the progression of cleft formation; 2) normalize facial development; and 3) allow for the scarless repair of these lateral atypical facial clefts. In a prospective randomized trial, eight 65-day gestational fetal lambs (term, 140 days) were exposed via a maternal hysterotomy. A Tessier 7 facial cleft was made by applying a 2.0 nylon suture as a constriction band to the growing face. The sutures were attached to the zygomatic arch and looped circumferentially into the oral commissure. Two weeks after surgery, four of eight animals were re-exposed. All four animals developed phenotypic changes consistent with Tessier 7 lateral facial clefts. These animals were treated in utero by 1) excising the synthetic constricting band, and 2) opening the epithelialized edges of the lateral facial clefts and performing a primary repair. At birth, the bands on the four untreated animals were cut. The lambs developed to 3 months of age, at which time they were evaluated anthropomorphically for changes in soft tissue measurements, and histologically using hematoxylin and eosin and Mason trichrome stain for the degree of scar at the repair site. Tessier 7 lateral facial clefts were produced in all the untreated animals. Each developed macrostomia with an average 2.3-cm lateral displacement of the oral commissure and partial maxillary clefting induced by the pressure of the restriction band. No evidence of tissue necrosis, maceration, or ulceration was noted. In contrast, animals treated in utero were phenotypically normal. There was no evidence of macrostomia and all anthropomorphic measurements were symmetrical. No bony clefts were seen on gross examination. Histologically, there was no evidence of scar formation at the site of the cleft repair. These findings suggest that like the standard cleft lip, atypical lateral facial clefts can be repaired successfully in utero without scarring. Furthermore, lysis of a restriction band in utero can prevent the progression of this facial deformity, leading to normal development of the face.

Adverse outcomes following endoscopic repair of a fetal cleft lip using an ovine model

OBJECTIVE

The purpose of this study was to determine if endoscopic techniques could be used to repair an epithelialized lip cleft with accuracy and with an outcome comparable to fetuses treated through an open hysterotomy.

INTERVENTIONS AND RESULTS

In contrast to previous open fetal cleft lip repairs in the same model, none of the five fetuses reported here had a good aesthetic result. Although there was no evidence of scar histologically, the edges of the lip were poorly approximated. The epithelial lining and underlying dermis of the wound margins were notably inverted. The orbicularis oris muscle, which had been reapproximated, appeared thin and hypoplastic. Most of the vermilion elements were poorly aligned, and in one animal, there was a complete dehiscence of the repair.

CONCLUSIONS

In a more representative model of cleft lip that is not an acute lip wound, in utero endoscopic suture repair of the ovine lip gave a poor result using current technology. Only a meticulously performed, multilayered, open repair of a cleft appears to give a good cosmetic and functional outcome. Further studies to improve the endoscopic repair as our technology advances are therefore warranted.

Comparison of indomethacin and nimesulide, a selective cyclooxygenase-2 inhibitor, on key pathophysiologic steps in the pathogenesis of nonsteroidal anti-inflammatory drug enteropathy in the rat

BACKGROUND

The predicted gastrointestinal tolerability of specific cyclooxygenase-2 inhibitors could be due to either a lack of 'topical' irritation and/or lack of effect on cyclooxygenase-1.

METHODS

Key pathophysiologic steps (in vitro and in vivo uncoupling, intestinal prostanoid levels (prostaglandin E, thromboxane B2, and 6-keto-prostaglandin F1alpha), intestinal permeability (51Cr-ethylenediaminetetraacetic acid), inflammation (faecal excretion of a granulocyte marker protein), and ulcer counts) in enteropathy induced by nonsteroidal anti-inflammatory drugs were assessed after administration of indomethacin, 10 mg/kg, and 15 (roughly equipotent), 30, and 60 mg/kg of the preferential cyclooxygenase-2 inhibitor nimesulide.

RESULTS

Indomethacin uncoupled oxidative phosphorylation at lower concentrations than nimesulide in vitro. Indomethacin was associated with electron microscopy changes suggestive of uncoupling in 60%-70% of enterocytes examined, whereas nimesulide affected 10%-30% of enterocytes, depending on the dose. Indomethacin increased intestinal permeability and caused inflammation and ulcers with 71%-96% reductions in prostanoid levels. Nimesulide at 15 mg/kg caused no damage, whereas 30 and 60 mg/kg nimesulide were associated with significant decreases in mucosal prostanoids (46%-75%), but only the 60-mg/kg dose caused a transient increase in intestinal permeability. However, at none of the doses did nimesulide cause intestinal inflammation or ulcers.

CONCLUSIONS

These results endorse the idea that selective cyclooxygenase-2 inhibitors may be associated with some gastrointestinal tolerance due to their selectivity for cyclooxygenase-2, inhibiting cyclooxygenase-1 at only very high doses, and reduced topical irritation.

Current microbiological status of 'health foods' sold in Canada

A follow-up survey was conducted across Canada to evaluate the current status of 'health foods' sold in Canada. A total of 1239 sample units of 'health foods' were analysed for a variety of bacteria, including aerobic colony counts (ACC), coliforms, aerobic and anaerobic sporeformers, Escherichia coli and Bacillus cereus. Results presented indicate that 16.8-18.4% of the 'health foods' exceed ACC guidelines, 16.0-17.8% exceeded coliform guidelines, 35.7% exceeded aerobic sporeformer guidelines, 81.4% exceeded anaerobic sporeformer guidelines, and 9% exceeded B. cereus guidelines. Some ACC were further identified and found to be opportunistic pathogens, including the genera Bacillus, Enterococcus, and Staphylococcus. It was concluded that more extensive surveillance of this industry by health officials is needed.

New method for detection of a bronchopleural fistula: direct instillation of Tc-99m DTPA into the pleural space via a thoracostomy tube

A 65-year-old man who had undergone a right upper lobectomy for squamous cell carcinoma developed a persistent air space in the right superior thorax. Because a bronchopleural fistula was suspected, a new technique to demonstrate the fistula was used. Five mCi of Tc-99m DTPA was instilled through a pigtail catheter into the cavity. Radiotracer activity extended into the remaining right bronchial tree, trachea, and left bronchial tree on the 10 minute delayed image confirming the presence of a bronchopleural fistula. Using bronchoscopic guidance, the fistula was sealed with a fibrin plug. A repeat examination 4 days later revealed no extension of tracer from the cavity up to 60 minutes after instillation, indicating successful sealing of the fistula. This technique offers a rapid, inexpensive, and portable diagnosis of bronchopleural fistula.

Abscisic acid signaling through cyclic ADP-ribose in plants

Abscisic acid (ABA) is the primary hormone that mediates plant responses to stresses such as cold, drought, and salinity. Single-cell microinjection experiments in tomato were used to identify possible intermediates involved in ABA signal transduction. Cyclic ADP-ribose (cADPR) was identified as a signaling molecule in the ABA response and was shown to exert its effects by way of calcium. Bioassay experiments showed that the amounts of cADPR in Arabidopsis thaliana plants increased in response to ABA treatment and before ABA-induced gene expression.

Signaling functions of the tyrosine residues in the betac chain of the granulocyte-macrophage colony-stimulating factor receptor

The granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor (GMR) is a heterodimeric receptor expressed by myeloid lineage cells. Binding of GM-CSF activates at least one receptor-associated tyrosine kinase, JAK2, and rapidly induces tyrosine phosphorylation of the GMR betac-chain (GMRbeta), but not the GMR alpha-chain (GMRalpha). To examine the role of GMRbeta tyrosine phosphorylaiton, each of the 8 tyrosine residues in the cytoplasmic domain of the human GMRbeta was mutated to phenylalanine (GMRbeta-F8), and this mutant receptor was expressed with wild-type GMRalpha in the interleukin-3-dependent murine hematopoietic cell line, Ba/F3. GM-CSF induced tyrosine phosphorylation of multiple cellular proteins in cells expressing GMRbeta-F8 , including JAK2 and STAT5. However, GM-CSF-induced tyrosine phosphorylation of both SHP2 and SHC was reduced or absent compared with wild-type. Next, a series of 8 receptors were generated, each containing only a single, restored, tyrosine residue. Tyrosine 577 was found to be sufficient to regenerate GM-CSF-dependent phosphorylation of SHC, and any of Y577, Y612, or Y695 was sufficient to regenerate GM-CSF-inducible phosphorylation of SHP2. Despite the signaling defect to SHC and SHP2, Ba/F3 cells expressing GMRbeta-F8 were still able to proliferate in response to 10 ng/mL of human GM-CSF, although mitogenesis was impaired compared with wild-type GMRbeta, and this effect was even more prominent at lower concentrations of GM-CSF (1 ng/mL). Overall, these results indicate that GMRbeta tyrosine residues are not necessary for activation of the JAK/STAT pathway or for proliferation, viability, or adhesion signaling in Ba/F3 cells, although tyrosine residues significantly affect the magnitude of the response. However, specific tyrosine residues are needed for activation of SHC and SHP2.

A new in utero model for lateral facial clefts

The etiopathogenesis behind the formation of atypical craniofacial facial clefts remains unknown. To test the hypothesis that physical restricting forces such as amniotic bands can lead to the formation of these unusual clefts in the postorganogenesis period, we have modified a previously reported fetal lamb model of amniotic band syndrome to examine the effects of these bands on craniofacial development. Five 70-day gestation fetal lambs (term, 140 days) were exposed via a maternal hysterotomy. In each animal, an attempt was made to create a lateral craniofacial cleft by applying a 2-0 nylon suture as a constriction band to the growing face. The sutures were attached to either the zygomatic arch or the infraorbital rim externally and then looped circumferentially into the oral commissure. Each suture was positioned so as to create either a Tessier type 5 or a Tessier type 7 cleft. Four of five fetal lambs survived to term. Both types of lateral facial clefts were effectively produced using this model. In each group, the presence of an intraoral constriction band led to the formation of macrostomia, with an average 7.4-mm lateral displacement of the oral commissure. In addition to these soft tissue changes, each animal also had partial bony clefting (i.e., a bony groove) induced by the pressure of the restriction band across the growing facial skeleton. In the two lambs with the Tessier type 7 cleft, incomplete bony clefts developed across the zygomatic arch. In three animals with bands placed across the medial infraorbital rim, significant infraorbital and malar bony clefts formed similar to a classic Tessier type 5 facial cleft. No evidence of tissue necrosis, maceration, or ulceration was noted in any animal. These data present, for the first time, evidence that the constriction of craniofacial growth by external forces such as a swallowed amnionic band can lead to the development of lateral facial clefting involving both soft tissue and bony elements. These malformations are likely due to a combination of directly tethering normal tissue migration and an increase in local pressure, which produces cellular ischemia and apoptosis. Furthermore, our data demonstrate that these clefts can occur later in fetal development during a period of facial growth rather than during the period of primary facial morphogenesis.

Australian bat lyssavirus infection in three fruit bats from north Queensland

We report the case findings of Australian bat lyssavirus infection in two black flying foxes (Pteropus alecto) and one little red flying fox (Pteropus scapulatus) from north Queensland between January 1995 and August 1996. Although the P. alecto case in January 1995 is the first recognised case of Australian bat lyssavirus infection in Australia, this was a retrospective diagnosis made after identification of the index case at Ballina in May 1996. Eight persons had exposure to the three bats. Serum antibodies to classical rabies virus were measured in six of these persons; the only one seropositive was a veterinarian who had previously been vaccinated against rabies. Six persons received rabies vaccine following exposure. None of the in-contact humans developed signs of lyssavirus infection. For people exposed to Australian bat lyssavirus-positive bats who have not been scratched or bitten or had mucosal contamination by these bats, we suggest a post-exposure regime of five inoculations of the human diploid cell inactivated rabies vaccine.

Identification of a novel human Rho protein with unusual properties: GTPase deficiency and in vivo farnesylation

We have identified a human Rho protein, RhoE, which has unusual structural and biochemical properties that suggest a novel mechanism of regulation. Within a region that is highly conserved among small GTPases, RhoE contains amino acid differences specifically at three positions that confer oncogenicity to Ras (12, 59, and 61). As predicted by these substitutions, which impair GTP hydrolysis in Ras, RhoE binds GTP but lacks intrinsic GTPase activity and is resistant to Rho-specific GTPase-activating proteins. Replacing all three positions in RhoE with conventional amino acids completely restores GTPase activity. In vivo, RhoE is found exclusively in the GTP-bound form, suggesting that unlike previously characterized small GTPases, RhoE may be normally maintained in an activated state. Thus, amino acid changes in Ras that are selected during tumorigenesis have evolved naturally in this Rho protein and have similar consequences for catalytic function. All previously described Rho family proteins are modified by geranylgeranylation, a lipid attachment required for proper membrane localization. In contrast, the carboxy-terminal sequence of RhoE predicts that, like Ras proteins, RhoE is normally farnesylated. Indeed, we have found that RhoE in farnesylated in vivo and that this modification is required for association with the plasma membrane and with an unidentified cellular structure that may play a role in adhesion. Thus, two unusual structural features of this novel Rho protein suggest a striking evolutionary divergence from the Rho family of GTPases.

Enhanced intracoronary thrombolysis with urokinase using a novel, local drug delivery system. In vitro, in vivo, and clinical studies

BACKGROUND

Current pharmacological regimens for treating intracoronary thrombus in the cardiac catheterization laboratory generally involve the administration of thrombolytic agents that result in a systemic fibrinolytic state and/or require prolonged arterial drug infusion. The purpose of the present study was to assess a new technique for treating intracoronary thrombus consisting of the local infusion of limited quantities of urokinase with a novel drug delivery device.

METHODS AND RESULTS

THe Dispatch coronary infusion catheter is a new local drug delivery system that allows for the prolonged infusion of therapeutic agents at an angioplasty site while distal coronary flow is maintained. Three experimental protocols were performed to determine the in vitro, in vivo, and clinical efficacy of this device. First, in vitro thrombolysis of fresh, porcine thrombus trapped in a 4-mm plastic tube with a 50% constriction and perfused with 20% porcine plasma was measured. Twenty-three thrombi were weighed before and after no treatment (n = 5), "systemic" urokinase administration (n = 4), local infusion of 150,000 U urokinase with a standard end-hole catheter (n = 4), local infusion of saline with the Dispatch catheter (n = 5), and local infusion of 150,000 U urokinase with the Dispatch catheter (n = 5). Second, 25 porcine coronary arteries in 23 pigs were dilated in vivo with conventional balloon angioplasty and then treated with 123I-labeled urokinase that was administered either by the Dispatch catheter (150,000 U; n = 16), intravenous systemic bolus (1,000,000 U; n = 3), guiding catheter infusion (500,000 U; n = 3), or local end-hole catheter infusion (150,000 U; n = 3). All vessels were subsequently harvested to quantify intramural deposition and subsequent washout of urokinase at the angioplasty site. Finally, 19 patients with angiographic evidence of intracoronary thrombus were treated with local urokinase infusion with the Dispatch catheter either before or after balloon angioplasty or directional atherectomy. In vitro studies demonstrated that infusion of urokinase with the Dispatch catheter decreased thrombus weight by 66% compared with no treatment (-25%), "systemic" urokinase administration (25%), end-hole catheter urokinase infusion (32%), or infusion of saline by the Dispatch catheter (32%) (P < or = .005). In vivo studies demonstrated immediate deposition of 0.12% of the urokinase delivered by the Dispatch catheter to the angioplasty site, compared with 0.0007% with systemic bolus, 0.003% with guiding catheter infusion, and 0.007% with local infusion with an end-hole catheter (P < .001). Urokinase deposited by the Dispatch catheter persisted intramurally for at least 5 hours. Patient studies demonstrated reduction of thrombus-containing stenoses and complete disappearance of intracoronary thrombus in all cases in which 150,000 U urokinase was locally infused over 30 minutes. There was no evidence of abrupt closure, distal embolization, or no reflow in any patient.

CONCLUSIONS

Local urokinase delivery with the Dispatch catheter can result in rapid and complete intracoronary thrombolysis using substantially less drug than standard thrombolytic techniques. Intramural deposition of drug with this technique creates a local reservoir of urokinase that may provide prolonged thrombolytic activity at the infusion site.

p190 RhoGAP, the major RasGAP-associated protein, binds GTP directly

In mitogenically stimulated cells, a specific complex forms between the Ras GTPase-activating protein (RasGAP) and the cellular protein p190. We have previously reported that p190 contains a carboxy-terminal domain that functions as a GAP for the Rho family GTPases. Thus, the RasGAP-p190 complex may serve to couple Ras- and Rho-mediated signalling pathways. In addition to its RhoGAP domain, p190 contains an amino-terminal domain that contains sequence motifs found in all known GTPases. Here, we report that p190 binds GTP and GDP through this conserved domain and that the structural requirements for binding are similar to those seen with other GTPases. While the purified protein is unable to hydrolyze GTP, we detect an activity in cell lysates that can promote GTP hydrolysis by p190. A mutated form of p190 that fails to bind nucleotide retains its RasGAP binding and RhoGAP activities, indicating that GTP binding by p190 is not required for these functions. The sequence of p190 in the GTP-binding domain, which shares structural features with both the Ras-like small GTPases and the larger G proteins, suggests that this protein defines a novel class of guanine nucleotide-binding proteins.

Ureaplasma diversum as a cause of reproductive disease in cattle

This article includes a brief review of the classification, habitat, and characteristics of the ureaplasmas, followed by a discussion of the pathogenesis, transmission, clinical syndromes, diagnosis, immunity, and treatment of Ureaplasma diversum infections in cattle.

The rice bZIP transcriptional activator RITA-1 is highly expressed during seed development

Systematic protein-DNA binding studies have shown that plant basic leucine zipper (bZIP) proteins exhibit a differential binding specificity for ACGT motifs. Here, we show that the rice transcription activator-1 (RITA-1) displays a broad binding specificity for palindromic ACGT elements, being able to bind A-, C-, and G-box but not T-box elements. By using gel mobility shift assays with probes differing in sequences flanking the hexameric core, we identified high-affinity A-, C-, and G-box binding sites. Quantitative and competition DNA binding studies confirmed RITA-1 specificity for these sites. Using rice protoplasts as a transient expression system, we demonstrated that RITA-1 can transactivate reporter genes possessing high-affinity but not low-affinity RITA-1 binding sites. Our results established a direct relationship between in vivo transactivation and in vitro binding activity. Transient expression assays that demonstrated the ability of RITA-1 to transactivate a construct containing rita-1 5' flanking sequences suggest that the factor may be autoregulated. Histochemical analysis of transgenic rice plants showed that a rita-1-beta-glucuronidase transgene is expressed in aleurone and endosperm cells of developing rice seeds. We propose that RITA-1 plays a role in the regulation of rice genes expressed in developing rice seeds.

An unusual pattern of metastases from Merkel cell carcinoma

An unusual case of Merkel cell carcinoma is presented in which the time course to development of nodal and haematogenous metastases was protracted and the predominant site of metastatic disease was small bowel.

A comparison of six different plating media used in the isolation of Salmonella

Seventeen Canadian Federal, Provincial and Public Health Laboratories took part in different phases of a comparative/collaborative study that evaluated rapid methods to the standard Health Protection Branch (HPB) method for the detection of Salmonella. A variety of commercial media were tested, including Brilliant Green Sulpha Agar, Bismuth Sulphite Agar, Hektoen Enteric Agar, Xylose Lysine Deoxycholate Agar, EF-18 Agar and Rambach Agar. Each laboratory compared up to six of these different plating media. Plating of 123 salmonellae cultures and 28 artificially-inoculated foods showed the recovery of Salmonella spp. on the six plating media to be within one log. Therefore, quantitative testing of the media showed them to be comparable in the recovery of salmonellae. Qualitative testing of the six media during the comparative/collaborative study of various methods showed that EF-18 Agar recovered the greatest number of isolates. Hektoen Enteric Agar ranked second, with the other agars being comparable in their recovery of Salmonella spp. Problems with the various media are summarized. Based on our results and those of other researchers, it is recommended that Bismuth Sulphite Agar be compulsory and that at least one other agar be used for newly developed cultural procedures.