An adipogenic cofactor bound by the differentiation domain of PPARgamma

Ligand activation of the nuclear receptor PPARgamma induces adipogenesis and increases insulin sensitivity, while activation of other PPAR isoforms (-alpha and -delta) induces little or no fat cell differentiation. Expression and activation of chimeras formed between PPARgamma and PPARdelta in fibroblasts has allowed us to localize a major domain of PPARgamma responsible for adipogenesis to the N-terminal 138 amino acids, a region with AF-1 transcriptional activity. Using this region of PPARgamma as bait, we have used a yeast two-hybrid screen to clone a novel protein, termed PGC-2, containing a partial SCAN domain. PGC-2 binds to and increases the transcriptional activity of PPARgamma but does not interact with other PPARs or most other nuclear receptors. Ectopic expression of PGC-2 in preadipocytes containing endogenous PPARgamma causes a dramatic increase in fat cell differentiation at both the morphological and molecular levels. These results suggest that interactions between PGC-2, a receptor isoform-selective cofactor and PPARgamma contribute to the adipogenic action of this receptor.

Transient pseudohypoaldosteronism secondary to obstructive uropathy in infancy

A syndrome of renal tubular resistance to aldosterone has been identified in infants with obstructive uropathy and urinary tract infection. Six infants (ages 9 days to 7 months) were seen with fever, vomiting, polyuria, dehydration, or failure to thrive. Urine cultures were positive for Escherichia coli. Radiologic studies demonstrated bilateral ureterohydronephrosis (four patients), left ureteral duplication with upper pole hydronephrosis (one), and left vesicoureteral reflux (one). The infants had hyponatremia, hyperkalemia, and metabolic acidosis. Plasma aldosterone concentration was markedly elevated, and plasma renin activity was similar to or higher than that reported in normal infants of comparable age. Fractional excretion of potassium was not significantly different from control values, both in absolute terms or when related to glomerular filtration rate, but fractional sodium excretion was significantly increased. The UK/UNa ratio was significantly lower in the patients. After medical or surgical therapy (when appropriate), all blood and urine determinations returned to normal, except for UK/UNa values, which although higher, remained significantly diminished. Our data indicate that a hyperkalemic salt-losing state can arise in infants with obstructive uropathy and urinary tract infection as a consequence of tubular unresponsiveness to aldosterone, and that the clinician should rule out such cause before establishing the diagnosis of primary pseudohypoaldosteronism.

Production of soluble and cell-associated fibronectin by cultured keratinocytes

Fibronectin has been demonstrated in epithelial cell types in culture, but published studies of keratinocytes have shown patterns of fibronectin produced by cells grown in medium with serum, which contains fibronectin. Since plasma fibronectin can bind to cells in vitro, cells grown in serum-supplemented media could show artifactual patterns of cell-associated fibronectin. To study insoluble fibronectin produced by keratinocytes, we plated cells in the absence of feeder layers in medium lacking fibronectin. Medium conditioned by metabolically labeled keratinocytes was studied by immunoprecipitation and by extraction with gelatin-Sepharose. Cells grown in fibronectin-free medium were labeled using affinity-purified anti-fibronectin antibody and fluorescein-conjugated antirabbit IgG. Keratinocytes produced soluble fibronectin, since both immunoprecipitation and adsorption to gelatin-Sepharose detected 35S-methionine-labeled material which comigrated with human plasma fibronectin on sodium dodecyl sulfate polyacrylamide gels. Demonstration of insoluble, cell-associated fibronectin was enhanced in Triton X-100-extracted cells and was seen in subcellular fibrillar arrays at both physiologic and reduced Ca++ concentrations, but in intracellular locations only at physiologic Ca++ concentrations. When cells grown in 1.1 mM Ca++ were removed with Triton X-100, diffusely distributed fibrillar fibronectin remained on the surface of the coverslip. Asymmetric "tracks" of fibronectin left by sparsely plated cells suggested movement. Fibronectin is deposited by keratinocytes on the culture surface and may be modulated by culture conditions.

Endometrial blood flow mapping using transvaginal power Doppler sonography in women with postmenopausal bleeding and thickened endometrium

OBJECTIVE

To evaluate the role of transvaginal power Doppler sonography to discriminate between benign and malignant endometrial conditions in women presenting with postmenopausal bleeding and thickened endometrium at baseline sonography.

METHODS

Ninety-one postmenopausal women (median age, 58 years; range, 47-83 years) presenting with uterine bleeding and a thickened endometrium (> or = 5-mm double-layer endometrial thickness) on transvaginal sonography were included in this prospective study. Endometrial blood flow distribution was assessed in all patients by power Doppler immediately after B-mode transvaginal sonography. Three different vascular patterns were defined: Pattern A: multiple-vessel pattern, Pattern B: single-vessel pattern and Pattern C: scattered-vessel pattern. Histological diagnoses were obtained in all cases. No patient taking tamoxifen citrate or receiving hormone replacement therapy was included.

RESULTS

Histological diagnoses were as follows: endometrial cancer: 33 (36%), endometrial polyp: 37 (41%), endometrial hyperplasia: 14 (15%), endometrial cystic atrophy: 7 (8%). Blood flow was found in 97%, 92%, 79% and 85% of cases of carcinoma, polyp, hyperplasia and endometrial cystic atrophy, respectively. A total of 81.3% of vascularized endometrial cancers showed Pattern A, 97.1% of vascularized polyps exhibited Pattern B and 72.7% of vascularized hyperplasias showed Pattern C. Sensitivity and specificity for endometrial cancer were 78.8% and 100%. For endometrial polyp these respective values were 89.2% and 87% and for hyperplasia they were 57.1% and 88.3%.

CONCLUSIONS

Transvaginal power Doppler blood flow mapping is useful to differentiate benign from malignant endometrial pathology in women presenting with postmenopausal bleeding and thickened endometrium at baseline sonography.

Ontogeny influences sensitivity to climate change stressors in an endangered fish

Coastal ecosystems are among the most human-impacted habitats globally, and their management is often critically linked to recovery of declining native species. In the San Francisco Estuary, the Delta Smelt (Hypomesus transpacificus) is an endemic, endangered fish strongly tied to Californian conservation planning. The complex life history of Delta Smelt combined with dynamic seasonal and spatial abiotic conditions result in dissimilar environments experienced among ontogenetic stages, which may yield stage-specific susceptibility to abiotic stressors. Climate change is forecasted to increase San Francisco Estuary water temperature and salinity; therefore, understanding the influences of ontogeny and phenotypic plasticity on tolerance to these critical environmental parameters is particularly important for Delta Smelt and other San Francisco Estuary fishes. We assessed thermal and salinity limits in several ontogenetic stages and acclimation states of Delta Smelt, and paired these data with environmental data to evaluate sensitivity to climate-change stressors. Thermal tolerance decreased among successive stages, with larval fish exhibiting the highest tolerance and post-spawning adults having the lowest. Delta Smelt had limited capacity to increase tolerance through thermal acclimation, and comparisons with field temperature data revealed that juvenile tolerance limits are the closest to current environmental conditions, which may make this stage especially susceptible to future climate warming. Maximal water temperatures observed in situ exceeded tolerance limits of juveniles and adults. Although these temperature events are currently rare, if they increase in frequency as predicted, it could result in habitat loss at these locations despite other favourable conditions for Delta Smelt. In contrast, Delta Smelt tolerated salinities spanning the range of expected environmental conditions for each ontogenetic stage, but salinity did impact survival in juvenile and adult stages in exposures over acute time scales. Our results underscore the importance of considering ontogeny and phenotypic plasticity in assessing the impacts of climate change, particularly for species adapted to spatially and temporally heterogeneous environments.

Natural history of primary distal renal tubular acidosis treated since infancy

Clinical and pathophysiologic studies were performed in five unrelated children with primary distal renal tubular acidosis who were diagnosed during infancy and followed for 3 to 9 1/2 years. All patients had permanent defects in hydrogen ion secretion, sodium reabsorption, and concentrating capacity. A transient, age-related, proximal tubular defect in sodium and bicarbonate reabsorption was also present. Renal bicarbonate wasting was mainly observed during the first years of life and progressively decreased with advancing age. Glomerular filtration rate remained within normal limits. Following sustained therapy with sodium and potassium bicarbonate, the patients had optimal growth, arrest of progression of nephrocalcinosis, and lack of other characteristic features of the disease with the exception of polyuria. Dosage of alkali was mainly determined by the magnitude of the renal bicarbonate loss and decreased progressively from a maximum of 3.9 to 10.0 mEq/kg/day during the first year of life to about 3 mEq/kg/day at or beyond 6 years of age. The total dosage of alkali required could be derived by the sum of the urinary excretion of bicarbonate plus 2 mEq/kg/day, which represents mean endogenous acid production. Although calciuria was normal when metabolic acidosis was corrected, patients with higher urinary sodium excretion had higher urinary excretion of calcium and thus were at greater risk of developing nephrocalcinosis if therapy was not carefully controlled.

Madangolide and laingolide A, two novel macrolides from lyngbya bouillonii (Cyanobacteria)

Two new macrolide derivatives, madangolide (2) and laingolide A (3), have been isolated from the cyanobacterium Lyngbya bouillonii, collected in Papua New Guinea. Their structures (without stereochemistry) have been established by detailed high-field 1D and 2D NMR studies and, in the case of 3, by comparison with the spectroscopic data of laingolide (1), previously isolated from the same organism.

Resistance to antibiotic and heavy metals of motile aeromonads from Chilean freshwater

In this work the resistance of 172 motile Aeromonas isolates recovered from raw drinking water supplies (56), irrigation waters (60) and runoff waters receiving sewage (56), to some antibiotics and heavy metals was investigated by agar diffusion and agar dilution methods. A high proportion of isolates from all water sources showed resistance to carbenicillin, erythromycin, streptomycin, cephradine and cadmium, and susceptibility to chloramphenicol, kanamycin, gentamicin, tetracycline, nalidixic acid, trimethoprim-sulphametoxazole and chromium. No amikacin-resistant Aeromonas were recovered. No relationship was found between antimicrobial resistance and Aeromonas species, with the exception of cephradine, that exhibited a significantly higher activity against the A. sobria isolates than the other Aeromonas species (P < 0.05). Moderately polluted waters showed lower antibiotic multiresistance and metal susceptibility than unpolluted and highly polluted ones. Although significant differences (P < 0.05), between resistance frequencies to erythromycin, carbenicillin, streptomycin and cephradine were found among isolates from different sources, the antimicrobial resistance patterns of aeromonads could not be related to the level of faecal pollution. These results indicate that aeromonads resistant to antibiotics and heavy metals are easily recovered from water sources in Chile, posing a potential public health risk.

Electrochemical aptasensor of cellular prion protein based on modified polypyrrole with redox dendrimers

This work consists of the development of an electrochemical aptasensor based on polyprrole modified with redox dendrimers, able to detect human cellular prions PrP(C) with high sensitivity. The gold surface was modified by conductive polypyrrole film coupled to polyamidoamine dendrimers of fourth generation (PAMAM G4) and ferrocenyl group as redox marker. The aptamers were immobilized on the surface via biotin/streptavidin chemistry. Electrochemical signal was detected by ferrocenyl group incorporated between dendrimers and aptamers layers. We demonstrated that the interaction between aptamer and prion protein led to variation in electrochemical signal of the ferrocenyl group. The kinetics parameters (diffusion coefficient D and heterogeneous constant transfer ket) calculated from electrochemical signals demonstrate that the variation in redox signal results from the lower diffusion process of ions during redox reaction after prion interaction due to bulk effect of larger protein. The association of redox dendrimers with conducting polypyrrole leads to high sensitivity of PrP(C) determination with detection limit of 0.8 pM, which is three orders of magnitude lower, compared to flat ferrocene-functionalized polypyrrole. Detection of PrP(C) in spiked blood plasma has been achieved and demonstrated a recovery up to 90%.

Low-protein amino acid-supplemented diets for growing pigs: effect on expression of amino acid transporters, serum concentration, performance, and carcass composition

Pigs fed protein-bound AA appear to have a higher abundance of AA transporters for their absorption in the jejunum compared with the duodenum. However, there is limited data about the effect of dietary free AA, readily available in the duodenum, on the duodenal abundance of AA transporters and its impact on pig performance. Forty-eight pigs (24.3 kg initial BW) distributed in 4 treatments were used to evaluate the effect of the CP level and form (free vs. protein bound) in which AA are added to diets on the expression of AA transporters in the 3 small intestine segments, serum concentration of AA, and performance. Dietary treatments based on wheat and soybean meal (SBM) were 1) low-CP (14%) diet supplemented with L-Lys, L-Thr, DL-Met, L-Leu, L-Ile, L-Val, L-His, L-Trp, and L-Phe (LPAA); 2) as in the LPAA but with added L-Gly as a N source (LPAA+N); 3) intermediate CP content (16%) supplemented with L-Lys HCl, L-Thr, and DL-Met (MPAA); and 4) high-CP (22%) diet (HP) without free AA. At the end of the experiment, 8 pigs from LPAA and HP were sacrificed to collect intestinal mucosa and blood samples and to dissect the carcasses. There were no differences in ADG, ADFI, G:F, and weights of carcass components and some visceral organs between treatments. Weights of the large intestine and kidney were higher in HP pigs (P < 0.01). Expression of b(0,+) in the duodenum was higher in pigs fed the LPAA compared with the HP diet (P= 0.036) but there was no difference in the jejunum and ileum. In the ileum, y+ L expression tended to be higher in pigs fed the LPAA diet (P = 0.098). Expression of b(0,+) in LPAA pigs did not differ between the duodenum and the jejunum, but in HP pigs, the expression of all AA transporters was higher in the jejunum than in the duodenum or ileum (P < 0.05). The serum concentration of Arg, His, Ile, Leu, Phe, and Val was higher but serum Lys and Met were lower in pigs fed the HP diet (P < 0.05). These results indicate that LPAA can substitute up to 8 percentage units of protein in HP wheat-SBM diets without affecting pig performance; nonessential N does not seem to be limiting in very low-protein wheat-SBM diets for growing pigs. Also, the inclusion of free AA in the diet appears to affect their serum concentration and the expression of the AA transporter b0,+ in the duodenum of pigs.

Operational factors and nutrient effects on activated sludge treatment of Pinus radiata kraft mill wastewater

The biodegradability of Pinus radiata bleached kraft mill wastewater by an activated sludge treatment during a period of 280 days was evaluated. The effect of varying hydraulic retention time (HRT) in the range of 48 to 4.5 h and nitrogen (N) and phosphorus (P) addition on removal of biological oxygen demand (BOD5), chemical oxygen demand (COD), suspended solids (TSS and VSS), total phenolic compounds, tannin and lignin and reduction of toxicity was investigated. Removal of BOD5 was higher than 90% when HRT varied from 16 to 6 h, but decreased when HRT was less than 6 h. Similar performance was observed for COD removal, which was about 60% when HRT was varied from 16 to 6 h. Removal of total phenolic compounds and tannin and lignin was seriously affected by HRT. N and P addition to maintaining a ratio of 100:5:0.3 provided optimal BOD5, COD and suspended solids removal when HRT varied from 16 to 7 h, and no toxicity (using Daphnia) was detected in the treated effluent. When HRT was less than 6 h, the system showed destabilisation and pH, COD, BOD5 and suspended solids removal decreased.

Transient transcriptional activation of the Vibrio cholerae El Tor virulence regulator toxT in response to culture conditions

Vibrio cholerae El Tor require special in vitro culture conditions, consisting of an initial static growth period followed by shift to shaking (AKI conditions), for expression of cholera toxin (CT) and toxin coregulated pili (TCP). ToxT, a regulator whose initial transcription depends on the ToxR regulator, positively modulates expression of CT and TCP. To help understand control of CT and TCP in El Tor vibrios, we monitored ctxAB and ToxR-dependent toxT transcription by time course primer extension assays. AKI conditions stimulated CT synthesis with an absence of ctxAB transcription during static growth followed by induction upon shaking. ToxR-dependent toxT transcription was induced at the end of the static growth period but was transient, stopping shortly after shaking was initiated but, interestingly, also if the static phase was prolonged. Immunoblot assays showed that ToxR protein levels were not coincidentally transient, implying a protein on/off switch mechanism for ToxR. Despite the transient activation by ToxR, transcription of ctxAB was maintained during shaking. This finding suggested continued toxT expression, possibly through relay transcription from another promoter. The 12.6-kb distant upstream tcpA promoter responsible for expression of the TCP operon has been proposed to provide an alternate toxT message by readthrough transcription. Activation of the tcpA promoter is supported by increased expression of TcpA protein during the shaking phase of the culture. Readthrough transcription of toxT from tcpA would be compatible with reverse transcription-PCR evidence for a toxT mRNA at times when ToxR-dependent transcription was no longer detectable by primer extension.

Renal handling of sodium in premature and full-term neonates: a study using clearance methods during water diuresis

A study using fractional clearances during orally induced water diuresis was designed to delineate the mechanism underlying defective tubular reabsorption of sodium in very low-birth-weight neonates. The use of clearance methodology during maximal water diuresis may give an indirect estimate of distal sodium delivery [urine volume (V), CH2O + CNa + K], sodium reabsorption at the diluting segments (CH2O), and proportion of the distal load reabsorbed distally (CH2O/CH2O + CNa + K), when all values are corrected to 100 ml glomerular filtration rate. The study was carried out in 28 healthy newborn infants who were grouped according to conceptual age (CA): 13 infants with mean birth weight of 1370 +/- 330 g and mean CA of 31.8 wk (range, 28-34 wk), and 15 infants with mean birth weight of 2330 +/- 550 g and mean CA of 37.9 wk (range, 35-41 wk). All studies were performed at 6-7 days of age. It was demonstrated that higher urinary osmolality (67.5 +/- 23.2 versus 52.9 +/- 9.4 mOsm/kg, P less than 0.0025) and higher fractional sodium excretion (2.3 +/- 1.8 versus 0.9 +/- 0.5 ml/dl glomerular filtration, P less than 0.01) observed in the group of very preterm infants resulted from significantly decreased proximal (V: 18.7 +/- 6.0 versus 13.3 +/- 3.6 ml/dl glomerular filtration, P less than 0.005; CH2O + CNa + K: 17.1 +/- 5.2 versus 11.9 +/- 3.3 ml/dl glomerular filtration, P less than 0.005) and distal (CH2O/CH2O + CNa + K X 100: 81.9 +/- 8.2 versus 88.2 +/- 4.5%, P less than 0.01) tubular sodium reabsorption.(ABSTRACT TRUNCATED AT 250 WORDS)

Opioid availability in Latin America: the Santo Domingo report progress since the Declaration of Florianopolis

The World Health Organization (WHO) has indicated that opioid analgesics are insufficiently available, particularly in developing countries, due to a variety of reasons, including legislative, educational, and policy issues. In its effort to promote the rational use of medical opioids and the adequate treatment of patients with cancer, WHO has sponsored a meeting of Latin American representatives every 2 years, which includes health professionals and government regulators. During March 24-27, 1996, a group of 86 representatives of cancer pain relief and palliative care programs from nine Latin American countries met in Santo Domingo under the auspices of the WHO Palliative Care Program for Latin America. For the first time since the First Latin American Meeting, government regulators were present to help address the issue of opioid availability from their perspective. During the meeting, issues pertaining to cancer pain, opioid availability, and palliative care were discussed. This report summarizes some of the events and presents a summary of the conclusions of an earlier meeting in 1994, as described in the Declaration of Florianopolis, and presents its follow-up, The Santo Domingo Report, generated following the 1996 meeting.

Biochemical features of dietary chloride deficiency syndrome: a comparative study of 30 cases

The diagnosis in one infant of a severe state of chloride deficiency after ingesting a diet consisting exclusively of a modified cow milk formula containing only 0.5 mEq/100 kcal chloride ion led to the identification of 30 additional infants (age 2.6 +/- 0.7 months) fed the same commercial formula. The total absence of chloride in the urine was used as a biochemical index of subclinical dietary chloride deficiency. Serum and urine values were studied at diagnosis and 10 to 12 days after chloride replenishment, and compared statistically with the values obtained in a control group of 40 infants (age 2.8 +/- 1.2 months) fed exclusively a different modified formula containing an adequate chloride concentration. The outstanding laboratory abnormalities noted in the infants ingesting a low chloride formula were hypochloremia and metabolic alkalosis. Mean serum concentrations of potassium, urea, creatinine, and uric acid were in the normal range, but group values were statistically different from normal. A previously unreported finding was the demonstration of a significant elevation in the serum concentrations of calcium and phosphate and in the urinary excretions of calcium and magnesium, which persisted after almost complete recovery of the remaining biochemical disturbances. These results indicate the potential risk of nephrocalcinosis after dietary chloride deficiency.

Thrombocytopenia in HIV-infected drug users in the HAART era

The present case-control study compared 26 HIV+ drug users having persistent thrombocytopenia (TCP<150 000/mm(3)) with 54 available age, gender and HIV CDC classification matched controls with normal platelet counts. Participants were followed longitudinally over a 2-year period (1998-2000), and hematological alterations evaluated in relationship to antiretroviral treatment, drug use and nutritional (selenium) status. Demographic information and medical history, including antiretroviral treatment were obtained. Blood was drawn for complete cell blood count, T lymphocytes and viral load. Sixty-nine percent of the individuals with persistent TCP and 49% of the controls were receiving antiretrovirals. At baseline, no significant differences in CD4 existed between the two groups. Over time, CD4 cell count declined in the cases (P = 0.05) and a significantly higher proportion of the cases (38%) developed AIDS (CD4<200 cell/mm(3)), as compared to the controls (18%, P = 0.004). A high risk for development of thrombocytopenia was observed with specific drug use (heroin 2.96 times, P = 0.0007), selenium levels below 145 microg/l (6 times, P = 0.008), and abnormal liver enzyme (SGOT) levels (2 times, P = 0.002). Together, these results indicate a number of factors that may be sensitive predictors of thrombocytopenia, which, despite antiretroviral treatment, appears to be related to more rapid disease progression in drug users.

Opioid availability in Latin America: the declaration of Florianopolis

Between March 27 and 29, 1994, a group of representatives of 32 palliative care programs from eight Latin American countries met under the auspices of the World Health Organization (WHO) Palliative Care Program for Latin America in Florianopolis, Brazil. The participants included physicians, nurses, psychologists, volunteers, drug regulators, hospital administrators, and representatives from the pharmaceutical industry. A comprehensive report by David Joranson (University of Wisconsin-Madison) was followed by a general discussion moderated by Jan Stjernsward, Chief of the Cancer Unit, World Health Organization, and by Eduardo Bruera, Coordinator of the WHO Cancer Pain and Palliative Care Program for Latin America. A number of issues related to opioid availability were identified and discussed. This declaration summarizes the main conclusions of the meeting. The attendants would like to encourage the widest possible distribution of this document.

Intratumoral blood flow in cervical cancer as assessed by transvaginal color doppler ultrasonography: Correlation with tumor characteristics

The objective of this study was to evaluate whether intratumoral blood flow as assessed by transvaginal color Doppler ultrasonography (TVCD) correlates with some tumor features in cervical cancer. Clinical, sonographic, and histologic data on 49 women (mean age: 50.3 years, range: 25-85 years) diagnosed as having a carcinoma from the uterine cervix were reviewed. Intratumoral blood flow was assessed by TVCD in all cases. Subjective impression of the amount of flow (scanty, moderate, or abundant) as well as the lowest resistance index (RI) and highest peak systolic velocity (PSV, cm/s) were used for analysis. These data were correlated with some tumoral features such as histologic type, histologic grade, tumor volume, and tumor stage. Intratumoral blood flow was found in all cases. Abundant blood flow was found more frequently in squamous carcinoma, moderately or poorly differentiated tumors, tumors with larger volume, and advanced stage tumors (P < 0.0001). Significantly lower RI was found in moderately or poorly differentiated tumors and advanced stage tumors (P < 0.01) and significantly higher PSV was found in moderately or poorly differentiated tumors, tumors with larger volume, and advanced stage tumors (P < 0.01). No correlation was found between RI and PSV and histologic type. Our data indicate that intratumoral blood flow as assessed by TVCD correlates well with some tumor features in cervical cancer.