Restoration of MYC-repressed targets mediates the negative effects of GM-CSF on RUNX1-ETO leukemogenicity

GM-CSF signaling regulates hematopoiesis and immune responses. CSF2RA, the gene encoding the α subunit for GM-CSF, is significantly downregulated in t(8;21) (RUNX1-ETO or RE) leukemia patients, suggesting that it may serve as a tumor suppressor. We previously reported that GM-CSF signaling is inhibitory to RE leukemogenesis. Here we conducted gene expression profiling of primary RE hematopoietic stem/progenitor cells (HSPCs) treated with GM-CSF to elucidate the mechanisms mediating the negative effects of GM on RE leukemogenicity. We observed that GM treatment of RE HSPCs resulted in a unique gene expression profile that resembles primary human cells undergoing myelopoiesis, which was not observed in control HSPCs. Additionally we discovered that GM-CSF signaling attenuates MYC-associated gene signatures in RE HSPCs. In agreement with this, a functional screen of a subset of GM-CSF-responsive genes demonstrated that a MYC inhibitor, MXI1, reduced the leukemic potential of RE HSPCs and t(8;21) AML cells. Furthermore, MYC knockdown and treatment with the BET inhibitor JQ1 reduced the leukemic potential of t(8;21) cell lines. Altogether, we discovered a novel molecular mechanism mediating the GM-CSF-induced reduction in leukemic potential of RE cells, and our findings support MYC inhibition as an effective strategy for reducing the leukemogenicity of t(8;21) AML.

Hepatocyte growth factor promotes tumor growth in a novel in vivo model of human lung cancer

Significant progress has been made toward identifying growth factors that display autocrine or paracrine effects on the growth of lung cancer cells. Determining the in vivo relevance of specific growth factors on lung tumor formation, however, has not often been demonstrated in laboratory models. Although hepatocyte growth factor (HGF) has been shown to have mitogenic and motogenic effects on human lung cancer cells in vitro, and to have prognostic importance in patients with lung cancer, the effects of HGF on tumor behavior in vivo remain unknown. We therefore developed an airway tumor xenograft model that allowed us to test the hypothesis that HGF promotes human non-small cell lung cancer (NSCLC) growth in vivo. Human airway tumor xenografts were created in Severe Combined Immunodeficient mice by injecting human lung adenocarcinoma cells into human bronchial segments. After determining the optimal times for tumor-cell injection and the time course of tumor growth, we evaluated the effects of HGF on tumor growth by injecting recombinant HGF, or saline as a control, into the lumen of tumor xenografts for 10 consecutive days. Histologic evaluation 2 to 3 wk later revealed that the HGF-injected xenografts had a significantly greater tumor volume and more tumor cells were located in the submucosal space than were found in the saline-injected xenografts. These data demonstrate the usefulness of this novel in vivo model to study NSCLC, and show that HGF promotes both the growth and invasion of human lung cancer in vivo.

Direct percutaneous jejunostomy: techniques and applications--ten years experience

PURPOSE

To present 10 years experience with direct fluoroscopically guided percutaneous jejunostomy.

MATERIALS AND METHODS

Percutaneous jejunostomy was performed in 62 patients, most of whom had undergone major abdominal surgery. A new or replacement jejunostomy was created for alimentation in 20 and 21 patients, respectively. Jejunostomy was performed for interventional procedures of the bile ducts or intestine in 13 patients and for retrograde gastroesophageal drainage in eight. The distended jejunum was accessed with a 21-gauge needle, immobilized with a gastric anchor, and catheterized with a 10-14-F locking loop drain.

RESULTS

The technical success rate was 19 of 20 (95%) for new feeding jejunostomy and 17 of 21 (81%) for replacement feeding jejunostomy. Jejunostomy facilitated drainage, dilation, stone extraction, and recanalization in the bile ducts or intestine in all 13 patients. Retrograde jejunoesophagogastrostomy suction effectively replaced painful nasogastric suction in all eight patients. Two patients who underwent replacement jejunostomy required laparotomy for possible leakage; there was no important procedure-related morbidity and no procedure-related mortality.

CONCLUSION

The technical success and complication rates of feeding percutaneous jejunostomy compare favorably with those of surgery or endoscopy. Percutaneous jejunostomy is a useful and underused approach to managing bowel and biliary obstruction.

Expression of mRNA for gastrin-releasing peptide receptor by human bronchial epithelial cells. Association with prolonged tobacco exposure and responsiveness to bombesin-like peptides

Bombesin-like peptides (BLPs) are important regulators of lung development and may also act as autocrine growth factors in lung tumors. We have previously demonstrated expression of mRNA for the three BLP receptor subtypes (neuromedin B [NMB]) receptor, gastrin-releasing peptide [GRP] receptor, and bombesin receptor subtype 3 [BRS-3]) in human non-small cell lung carcinoma (NSCLC) cell lines and bronchial biopsies using the reverse transcription-polymerase chain reaction (RT-PCR; DeMichele, et al. Am. J. Respir. Cell Mol. Biol. 1994; 11:66-74). We have also previously found that growth responses to BLPs could be elicited in some, but not all, cultures of human bronchial epithelial (HBE) cells (Siegfried, et al. Anat. Rec. 1993; 236:241-247). In this report, we utilized RT-PCR to demonstrate mRNA expression of BLP receptor subtypes in cultured HBE cells and also assessed the response of these cultures to BLPs in proliferation assays. The pattern of mRNA expression was correlated with proliferative response, and the results were also analyzed in relation to smoking history and pulmonary function of the subjects studied. Our results suggest that expression of mRNA for the GRP receptor is associated with a long smoking history (> 25 pack-years [PY], p = 0.02). This association was related to past tobacco exposure, regardless of whether the subjects were still active smokers at the time of tissue procurement. Responsiveness to GRP and NMB in proliferation assays was also found only in those HBE cultures with expression of mRNA for at least one of the known receptors for BLPs, and there was a significant association between expression of mRNA for the GRP receptor and proliferative response to both GRP and NMB (p = 0.048). HBE cultures from subjects with a greater than 25 PY smoking history were also more likely to respond to BLPs in the proliferation assays than cells from subjects with less than a 25 PY history (10 of 16 versus 1 of 7, p = 0.06). Cultures of HBE cells from four of the five subjects with severe obstructive lung disease gave a positive response to GRP and NMB in proliferation assays, compared to five of fifteen without severe obstructive lung disease, but this difference was not significant (p = 0.13). These results suggest there is an increased likelihood of expression of the GRP receptor mRNA in the respiratory epithelium of some individuals with a history of prolonged tobacco exposure, and that expression of the GRP receptor mRNA is accompanied by responsiveness to the mitogenic effects of BLPs. These effects appear to persist after smoking cessation.

Colouterine fistula: computed tomography and vaginography findings

Colouterine fistulas are difficult to demonstrate radiologically. The authors present a case in which such a fistula was observed with computed tomography and confirmed by vaginography.

Epidural diamorphine and bupivacaine in labour

A double-blind randomised study was performed to assess the analgesic effect of epidural diamorphine, administered with bupivacaine, on primigravid women in labour. Fifty patients received 0.25% bupivacaine 10 ml via the epidural catheter as their initial dose; patients in Group 1 received diamorphine 5 mg with the bupivacaine. A 0.1% bupivacaine infusion was started at 10 minutes and bolus doses of bupivacaine were given if required. There was a significant reduction in rate of bupivacaine administration, pain scores at 20 and 30 minutes, number of supplements required, and degree of motor blockade in the diamorphine group.

Lignocaine 2% with adrenaline for epidural caesarean section. A comparison with 0.5% bupivacaine

A randomised double blind controlled trial of freshly prepared 2% lignocaine with 1/200,000 adrenaline and 0.5% plain bupivacaine was conducted on 60 women undergoing elective Caesarean section. The use of the former enabled epidural blockade to above the T6 dermatome to be established in a significantly shorter time than with bupivacaine (p less than 0.005). The quality of sensory blockade and incidence of complications was similar in the two groups. The solutions were of similar potency as measured by the volume required per segment blocked. Motor blockade was more intense with 2% lignocaine with adrenaline (p less than 0.03). More neonates had moderately depressed Apgar scores (5-7) at one minute in the lignocaine group but this difference was not statistically significant, and there was no difference in the distribution of Apgar scores at 3 minutes. Lignocaine with 1/200,000 adrenaline is a useful alternative to 0.5% plain bupivacaine when it is desired to establish rapidly epidural blockade for Caesarean section.

Spina bifida occulta and epidural anaesthesia

Spina bifida occulta occurs in 5-10% of the population, not all of whom display superficial signs. Attempted epidural puncture at the level of the lesion will almost certainly result in a dural tap. We report a patient who developed a postural headache after Caesarean section under epidural anaesthesia, in whom radiography of the spine later demonstrated spina bifida occulta. This problem has not been described previously, although it is unlikely to be an isolated case.

Documenting the activity and effectiveness of a regional drug information center

The methods of data collection, storage, and retrieval used by the Rocky Mountain Drug Consultation Center (RMDCC) are described. To substantiate that drug information services provided by RMDCC are clinically useful and have a beneficial effect on therapy, data on medication-related problems and case outcomes, as well as demographic data, are stored in an IBM PC-XT using a system that allows searching and linkage of any number of recorded categories. Data were compiled on 28,081 inquiries from health-care professionals and consumers during 1985 and 1986. Analysis revealed that (1) medication-related problems are common (involving 34% of consumer inquiries), especially among the elderly; (2) a positive effect on therapy was made in the majority (76%) of problem cases; and (3) consumers were given drug information by their physician or pharmacist in fewer than half of the cases in which medications were prescribed and dispensed. A computer-based system to assist in analyzing information can be an important asset in documenting the activity and effectiveness of a regional drug information center.

Anaesthesia for Caesarean section. The potential for regional block

This study of the obstetric and anaesthetic circumstances relating to 100 consecutive Caesarean sections under general anaesthesia suggests that the general anaesthesia rate for Caesarean section could be reduced from the present 37 to 27% by making maximum use of epidural block and to 16% by using subarachnoid block in addition. The need for general anaesthesia on account of urgency to deliver can be greatly reduced by the administration of epidural analgesia during labour in patients identified as being more likely than average to require Caesarean section, and by the use of subarachnoid block when the need for section arises unexpectantly. Patients' objections to undergoing Caesarean section while conscious were analysed, and suggestions are made for minimising the number of patients who decline. Technical problems with blocks may sometimes be overcome without resort to general anaesthesia, while patients at risk from haemorrhage or coagulopathy will continue to require general anaesthesia.