Reconstitution of hyperacetylated, DNase I-sensitive chromatin characterized by high conformational flexibility of nucleosomal DNA

The normal pancreatic beta-cell population exhibits intercellular differences in its responsiveness to glucose. This cellular heterogeneity allows glucose to regulate, in a dose-dependent manner, total rates of insulin synthesis and release. It may also predispose to intercellular differences in susceptibility to dysregulating agents. The present study examines whether this is the case for interleukin 1beta (IL-1beta), which is known to suppress glucose-induced insulin synthesis and release. The effects of the cytokine were compared on beta-cell subpopulations with, respectively, high and low sensitivity to glucose. These subpopulations were separated on the basis of differences in the cellular metabolic responsiveness to an intermediate glucose concentration (7.5 mmol/liter) and then cultured for 20 h at 5 or 20 mmol/liter with or without IL-1beta. The suppressive action of IL-1beta (0.1 ng/ml) occurred predominantly in glucose-activated beta cells, reducing their high rates of insulin synthesis and release by more than 80%. Glucose-unresponsive cells became subject to a similar inhibition after their activation during culture at 20 mmol/liter glucose. On the other hand, IL-1beta induced or enhanced the expression of several noninsulin proteins in both subpopulations. The IL-1beta-stimulated expression of inducible nitric oxide synthase (iNOS) and heat shock protein 70 was more marked in the glucose-responsive subpopulation; that of heme oxygenase and Mn superoxide dismutase was comparable in the two subpopulations. Exposure to IL-1beta resulted in 10-fold higher medium nitrite levels in both subpopulations; this effect was prevented by the iNOS blocker, N(G)-methyl-L-arginine, which also prevented the IL-1beta-induced suppression in the glucose-responsive subpopulation. This study demonstrates that the cellular heterogeneity in glucose responsiveness predisposes to intercellular differences in the IL-1-induced suppression of insulin synthesis and release. While the cytokine induces the expression of noninsulin proteins such as iNOS in both glucose responsive and unresponsive cells, the subsequent nitric oxide production appears to predominantly affect glucose-stimulated functions in the glucose-activated cells.     

A lump in the breast. A rare first symptom of ovarian cancer

The breast is an uncommon site for metastasis from extramammary primaries. A 43-year-old woman presented with a lump in the left breast. A tumour with atypical microcalcifications was seen on the mammogram. Needle aspiration cytology revealed adenocarcinoma cells. The final histological diagnosis was papillary adenocarcinoma with psammoma bodies, probably secondary to an ovarian carcinoma. A bilateral carcinoma of the ovaries was subsequently diagnosed and treated. A mammary tumour with an atypical growth pattern and the absence of in situ carcinoma should always prompt the pathologist to considering the possibility of a metastatic tumour even though this is a rare occurrence. Earlier recognition of metastatic tumours to the breast may result in initiation of appropriate therapy and will preclude unnecessary surgical procedures.     

Persistent nicotinic blockade by chlorisondamine of noradrenergic neurons in rat brain and cultured PC12 cells

Chlorisondamine (CHL) blocks behavioural responses to nicotine for several weeks or months in rats. Persistent blockade has also been demonstrated ex vivo, in assays of nicotine-evoked striatal dopamine release. Central administration of [3H]-CHL leads to long-term retention of radiolabel in nigrostriatal dopaminergic neurons and in few other cell groups. We investigated whether an analogous blockade also occurs in noradrenergic neurons in the brain and in cultured pheochromocytoma (PC12) cells, which have a similar noradrenergic phenotype. Administration of CHL (10 mg kg(-1) s.c. or 10 microg i.c.v.), 21 days prior, resulted in a near-total block of nicotine-evoked release of hippocampal [3H]-noradrenaline ([3H]-NA) from superfused rat synaptosomes; NMDA-evoked [3H]-NA release was unaffected. Three weeks after administration of [3H]-CHL (10 microg i.c.v.), preferential accumulation of radiolabel was observed in the locus coeruleus, which provides the entire noradrenergic innervation to hippocampus, as well as in previously noted structures. In rat pheochromocytoma (PC12) cells, nicotine evoked [3H]-NA release (EC50 approximately 30 microM). This effect was blocked by co-incubation with mecamylamine (10 microM) or CHL (1 microM) but was not affected by alpha-bungarotoxin. As in the hippocampus, the nicotinic agonist cytisine was at least as efficacious as nicotine. Acute exposure of PC12 cells to CHL 10 or 100 microM (but not 1 microM), followed by 90 min wash-out, almost completely blocked release evoked by 30 microM nicotine. More prolonged (24 h) exposure to CHL 100 microM (but not 1 or 10 microM), followed by 3 days of wash-out, partially inhibited release evoked by nicotine, leaving responses to high K+ unchanged. A significant (30%) reduction was also seen 5 days after exposure. We conclude that persistent nicotinic blockade by CHL is neither restricted to mesostriatal dopamine neurons, nor to the CNS, nor to neurons possessing the same nicotinic receptor pharmacology. In addition, the persistent blockade does not appear to result from an acute blocking action, but may be dependent upon intracellular accumulation of the antagonist.     

Diet and humoral responsiveness of lines of chickens divergently selected for antibody response to sheep red blood cells

OBJECTIVE: To assess everyday life stress and emotional adjustment in patients with rheumatoid arthritis (RA) and their children. METHODS: We conducted a 6 month study of 14 patients with RA with children aged 4-16 years (25 children) and 24 control families (53 children). Life event stress and functional capacity were assessed at the beginning and end of the study, and minor stressors (hassles), positive events (uplifts), and salivary cortisol were recorded weekly. Emotional adjustment was measured monthly in adults by self-report, and bimonthly in children using the Child Behavior Checklist (completed by parents). Social support and psychological coping responses were also measured. RESULTS: Patients with RA experienced fewer positive events than did controls, and they tended to have smaller support networks. Daily hassle levels correlated with severity of disability, and differences in psychological coping were also observed. Children from RA families reported nearly 50% more hassles per week than did controls, and their social networks were significantly smaller. They were rated as having greater problems of social adjustment than controls. Cortisol concentration was greater among children who experienced more life event stress over the study period, but did not differ between groups. CONCLUSION: The patients with RA in this study showed good adaptation, but experienced less pleasure in their daily lives. The children of patients with RA may have heightened vulnerability to stress related problems, with fewer social resources and difficulties in behavioral adjustment.     

Mycobacterium ulcerans infection in a child from Angola: diagnosis by direct detection and culture

The purpose of this study is to listen to and interpret the experiences of independent older women in the community regarding their medication use. Their experiences were examined regarding medication information, sources of information, types of medication used, relationships with health care professionals and social support systems. The techniques used for data collection included guided qualitative semistructured interviews based on the principle of empowerment and notions of ideal and nonhierarchical communication. The emergent themes show that for these older women general practitioners were important in their medication experiences. Whilst trusted as carers in the acute care setting, registered nurses did not play a role in the medication experiences of these older women. Registered nurses are perceived as 'traditional carers' associated with medical and acute care settings. Although medication issues emerged that ideally required attention, the older women in this study generally perceived themselves to be capable of actively managing their health and medication use.     

Sarcomas and related proliferative lesions of specialized prostatic stroma: a clinicopathologic study of 22 cases

Sarcomas and related proliferative lesions of the specialized prostatic stroma have been the subject of case reports and, thus, have not been well characterized. We reviewed the clinicopathologic features of 22 cases and studied the immunohistochemical profile of 9. Patient age ranged from 25 to 86 years; mean age was 54 years, and peak incidence was in the 6th and 7th decades. The most common clinical presentation was urinary retention, then abnormal results of digital rectal examination, hematuria or hematospermia, and a palpable rectal mass. The cases were grouped into two categories: prostatic stromal proliferation of uncertain malignant potential (PSPUMP, 18 cases) and prostatic stromal sarcoma (PSS, 4 cases) based on the degree of stromal cellularity and the presence of mitotic figures, necrosis, and stromal overgrowth. Four histologic patterns of PSPUMP were identified: (1) hypercellular stroma with scattered cytologically atypical cells associated with benign glands, (2) hypercellular stroma with minimal cytological atypia associated with benign glands, (3) hypercellular stroma with or without cytologically atypical cells, associated with benign glands in a "leaflike" growth pattern that resembled phyllodes tumors of the mammary gland, and (4) hypercellular stroma without cytologically atypical stromal cells and without glands. Prostatic stromal sarcoma showed greater cellularity, mitoses, necrosis, and stromal overgrowth than PSPUMP and consisted either of stromal elements with benign glands in a pattern that resembled malignant phyllodes tumors of the mammary gland (3 cases) or of purely stromal elements (1 case). Positive immunohistochemical reactions were noted using vimentin in 9 of 9 cases, CD34 in 8 of 8, HHF-35 in 2 of 8, smooth muscle actin in 3 of 9, desmin in 4 of 8, S-100 protein in 0 of 9, estrogen receptor in 1 of 7, and progesterone receptor in 6 of 7. None of the cases classified as PSS were positive for HHF-35, smooth muscle actin, or desmin. Of the 13 patients classified as having PSPUMP who did not undergo definitive local therapy at the time of diagnosis, recurrent signs or symptoms were seen in six (46%), necessitating additional therapy. Distant metastases to lung and bone developed in one patient classified as having PSS. Clinical and pathologic findings in this patient suggested a progression from PSPUMP to PSS. We conclude that sarcomas and related proliferative lesions of the specialized prostatic stroma encompass a spectrum of histologic features and may be grouped into two clinicopathologic categories: PSPUMP and PSS. Based on their distinctive histologic appearance and immunohistochemical profile, PSPUMP and PSS can be differentiated from other mesenchymal lesions of the prostate.     

Calcium regulation of tension redevelopment kinetics with 2-deoxy-ATP or low [ATP] in rabbit skeletal muscle

The correlation of acto-myosin ATPase rate with tension redevelopment kinetics (k(tr)) was determined during Ca(+2)-activated contractions of demembranated rabbit psoas muscle fibers; the ATPase rate was either increased or decreased relative to control by substitution of ATP (5.0 mM) with 2-deoxy-ATP (dATP) (5.0 mM) or by lowering [ATP] to 0.5 mM, respectively. The activation dependence of k(tr) and unloaded shortening velocity (Vu) was measured with each substrate. With 5.0 mM ATP, Vu depended linearly on tension (P), whereas k(tr) exhibited a nonlinear dependence on P, being relatively independent of P at submaximum levels and rising steeply at P > 0.6-0.7 of maximum tension (Po). With dATP, Vu was 25% greater than control at Po and was elevated at all P > 0.15Po, whereas Po was unchanged. Furthermore, the Ca(+2) sensitivity of both k(tr) and P increased, such that the dependence of k(tr) on P was not significantly different from control, despite an elevation of Vu and maximal k(tr). In contrast, lowering [ATP] caused a slight (8%) elevation of Po, no change in the Ca(+2) sensitivity of P, and a decrease in Vu at all P. Moreover, k(tr) was decreased relative to control at P > 0.75Po, but was elevated at P < 0.75Po. These data demonstrate that the cross-bridge cycling rate dominates k(tr) at maximum but not submaximum levels of Ca(2+) activation.     

Hepatic lipase affects both HDL and ApoB-containing lipoprotein levels in the mouse

Transgenic mice were created overproducing a range of human HL (hHL) activities (4-23-fold increase) to further examine the role of hepatic lipase (HL) in lipoprotein metabolism. A 5-fold increase in heparin releasable HL activity was accompanied by moderate (approx. 20%) decreases in plasma total and high density lipoprotein (HDL) cholesterol and phospholipid (PL) but no significant change in triglyceride (TG). A 23-fold increase in HL activity caused a more significant decrease in plasma total and HDL cholesterol, PL and TG (77%, 64%, 60%, and 24% respectively), and a substantial decrease in lipoprotein lipids amongst IDL, LDL and HDL fractions. High levels of HL activity diminished the plasma concentration of apoA-I, A-II and apoE (76%, 48% and 75%, respectively). In contrast, the levels of apoA-IV-containing lipoproteins appear relatively resistant to increased titers of hHL activity. Increased hHL activity was associated with a progressive decrease in the levels and an increase in the density of LpAI and LpB48 particles. The increased rate of disappearance of 125I-labeled human HDL from the plasma of hHL transgenic mice suggests increased clearance of HDL apoproteins in the transgenic mice. The effect of increased HL activity on apoB100-containing lipoproteins was more complex. HL-deficient mice have substantially decreased apoB100-containing low density lipoproteins (LDL) compared to controls. Increased HL activity is associated with a transformation of the lipoprotein density profile from predominantly buoyant (VLDL/IDL) lipoproteins to more dense (LDL) fractions. Increased HL activity from moderate (4-fold) to higher (5-fold) levels decreased the levels of apoB100-containing particles. Thus, at normal to moderately high levels in the mouse, HL promotes the metabolism of both HDL and apoB-containing lipoproteins and thereby acts as a key determinant of plasma levels of both HDL and LDL.