Megakaryocytic colony formation in polycythaemia vera and secondary erythrocytosis

Megakaryocytic colony formation by progenitor cells of 18 patients with polycythaemia vera, seven with secondary erythrocytosis and four with erythrocytosis of unexplained origin was studied in vitro by the methyl cellulose culture assay. Fourteen of the 18 patients with polycythaemia vera showed spontaneous megakaryocytic colony formation, i.e. colony growth with normal human plasma as the only source of colony stimulation. None of the patients with secondary erythrocytosis or erythrocytosis of unknown origin or of the normal controls grew colonies in the presence of normal human plasma only. When the plasma of a patient with aplastic anaemia was used instead of normal human plasma and phytohaemagglutinin stimulated leucocyte conditioned medium (PHA-LCM) was added to the culture medium, two of the patients with polycythaemia vera and one with secondary erythrocytosis formed slightly increased numbers of megakaryocytic colonies, while the rest of the patients showed normal colony formation. All of the patients with polycythaemia vera but none of those with secondary erythrocytosis or erythrocytosis of unknown origin showed spontaneous erythroid colony growth. The present study shows that most patients with polycythaemia vera form spontaneous megakaryocytic colonies in vitro. This phenomenon has recently also been demonstrated in essential thrombocythaemia and it is apparently analogous to spontaneous erythroid colony growth seen in all myeloproliferative disorders.     

In vitro oxidations of low-density lipoprotein and RAW 264.7 cells with lipophilic O(3P)-precursors

A beneficial property of photogenerated reactive oxygen species (ROS) is the capability of oxidant generation within a specific location or organelle inside a cell. Dibenzothiophene S-oxide (DBTO), which is known to undergo a photodeoxygenation reaction to generate ground state atomic oxygen [O(³P)] upon irradiation, was functionalized to afford localization within the plasma membrane of cells. The photochemistry, as it relates to oxidant generation, was studied and demonstrated that the functionalized DBTO derivatives generated O(³P). Irradiation of these lipophilic O(³P)-precursors in the presence of LDL and within RAW 264.7 cells afforded several oxidized lipid products (oxLP) in the form of aldehydes. The generation of a 2-hexadecenal (2-HDEA) was markedly increased in irradiations where O(³P) was putatively produced. The substantial generation of 2-HDEA is not known to accompany the production of other ROS. These cellular irradiation experiments demonstrate the potential of inducing oxidation with O(³P) in cells.

Lipophilic O(³P)-precursors generate 2-hexadecenal upon UV-irradiation.     

Combination Therapies Prevent the Neuropathic,Proinflammatory Characteristics of Bone Marrow in Streptozotocin-Induced Diabetic Rats

We previously showed that peripheral neuropathy of the bone marrow was associated with loss of circadian rhythmicity of stem/progenitor cell release into the circulation. Bone marrow neuropathy results in dramatic changes in hematopoiesis that lead to microvascular complications, inflammation, and reduced endothelial repair. This series of events represents early pathogenesis before development of diabetic retinopathy. In this study we characterized early alterations within the bone marrow of streptozotocin (STZ)-induced diabetic rats following treatments that prevent experimental peripheral neuropathy. We asked whether bone marrow neuropathy and the associated bone marrow pathology were reversed with treatments that prevent peripheral neuropathy. Three strategies were tested: inhibition of neutral endopeptidase, inhibition of aldose reductase plus lipoic acid supplementation, and insulin therapy with antioxidants. All strategies prevented loss of nerve conduction velocity resulting from STZ-induced diabetes and corrected the STZ-induced diabetes–associated increase of immunoreactivity of neuropeptide Y, tyrosine hydroxylase, and somatostatin. The treatments also reduced concentrations of interleukin-1β, granulocyte colony-stimulating factor, and matrix metalloproteinase 2 in STZ-induced diabetic bone marrow supernatant and decreased the expression of NADPH oxidase 2, nitric oxide synthase 2, and nuclear factor-κB1 mRNA in bone marrow progenitor cells. These therapies represent novel approaches to attenuate the diabetic phenotype within the bone marrow and may constitute an important therapeutic strategy for diabetic microvascular complications.     

Patients' perspectives on the management of emotional distress in primary care settings

Objective  To investigate how important treatment for emotional distress is to primary care patients in general and to primary care patients with depression, and to evaluate the types of mental health interventions they desire. Design  Patient surveys. Setting  Five private primary care practices. Measurements and main results  Patients' desire for treatment of emotional distress and for specific types of mental health interventions were measured, as well as patients' ratings of the impact of emotional distress, the frequency of depressive symptoms, and mental health functioning. Of the 403 patients, 33% felt that it was “somewhat important” and 30% thought it was “extremely important” that their physician tries to help them with their emotional distress. Patient desire for this help was significantly related to a diagnosis of depression (P<.001), perceptions about the impact of emotional distress (p<.001), and mental health functioning (p<.001). Among patients with presumptive diagnoses of major and minor depression, 84% and 79%, respectively, felt that it was at least somewhat important that they receive this help from their physician. Sixty-one percent of all primary care patients surveyed and 89% of depressed patients desired counseling; 23% of all patients and 33% of depressed patients wanted a medication; and 11% of all patients and 5% of depressed patients desired a referral to a mental health specialist. Conclusions  A majority of these primary care patients and almost all of the depressed patients felt that it was at least somewhat important to receive help from their physician for emotional distress. The desire for this help seems to be related to the severity of the mental health problem. Most of the patients wanted counseling, but relatively few desired a referral to a mental health specialist. Funded by grant R01 MH51067 from the National Institute of Mental Health.     

Does Prior Abdominal Surgery Influence Conversion Rates and Outcomes of Laparoscopic Right Colectomy in Patients with Neoplasia?

Purpose  The study investigated the impact of prior abdominal surgery on conversions and outcomes of laparoscopic right colectomy. Methods  A consecutive series of 414 patients with cancer or adenomas who underwent a laparoscopic right colectomy from March 1996 to November 2006 were studied for surgical conversions and outcomes. Conversion was defined as an incision length > 7 cm. Results  Patients with prior abdominal surgery (n = 191) were compared with patients with no prior abdominal surgery (n = 223), and showed no significant differences in age, ASA classification, length of stay, operative time, blood loss, harvested nodes, tumor size, and specimen length. Significantly more wound infections occurred in the prior abdominal surgery group (22 vs.12, P = 0.023). Body mass index > 30 showed a three-fold increased risk of conversion. Fifteen percent of the no prior abdominal surgery patients and 17 percent of the prior abdominal surgery patients were converted (P > 0.05). Conversion was associated with a longer mean length of stay (8.8 days) relative to laparoscopically completed cases (6.3 days) regardless of prior abdominal surgery history (P < 0.0001). Conclusions  Laparoscopic right colectomy for neoplasia was not associated with a higher conversion rate or morbidity in patients with prior abdominal surgery. Prior abdominal surgery is not a contraindication to laparoscopic right colectomy. Presented at the 15th International Congress of the European Association of Endoscopic Surgery, Athens, Greece, July 4 to 7, 2007.     

Pyruvate carboxylase is critical for non–small-cell lung cancer proliferation

Anabolic biosynthesis requires precursors supplied by the Krebs cycle, which in turn requires anaplerosis to replenish precursor intermediates. The major anaplerotic sources are pyruvate and glutamine, which require the activity of pyruvate carboxylase (PC) and glutaminase 1 (GLS1), respectively. Due to their rapid proliferation, cancer cells have increased anabolic and energy demands; however, different cancer cell types exhibit differential requirements for PC- and GLS-mediated pathways for anaplerosis and cell proliferation. Here, we infused patients with early-stage non–small-cell lung cancer (NSCLC) with uniformly ¹³C-labeled glucose before tissue resection and determined that the cancerous tissues in these patients had enhanced PC activity. Freshly resected paired lung tissue slices cultured in ¹³C₆-glucose or ¹³C₅,¹⁵N₂-glutamine tracers confirmed selective activation of PC over GLS in NSCLC. Compared with noncancerous tissues, PC expression was greatly enhanced in cancerous tissues, whereas GLS1 expression showed no trend. Moreover, immunohistochemical analysis of paired lung tissues showed PC overexpression in cancer cells rather than in stromal cells of tumor tissues. PC knockdown induced multinucleation, decreased cell proliferation and colony formation in human NSCLC cells, and reduced tumor growth in a mouse xenograft model. Growth inhibition was accompanied by perturbed Krebs cycle activity, inhibition of lipid and nucleotide biosynthesis, and altered glutathione homeostasis. These findings indicate that PC-mediated anaplerosis in early-stage NSCLC is required for tumor survival and proliferation.