Biodegradation and biological treatments of cellulose, hemicellulose and lignin: an overview

In nature, cellulose, lignocellulose and lignin are major sources of plant biomass; therefore, their recycling is indispensable for the carbon cycle. Each polymer is degraded by a variety of microorganisms which produce a battery of enzymes that work synergically. In the near future, processes that use lignocellulolytic enzymes or are based on microorganisms could lead to new, environmentally friendly technologies. This study reviews recent advances in the various biological treatments that can turn these three lignicellulose biopolymers into alternative fuels. In addition, biotechnological innovations based on natural delignification and applied to pulp and paper manufacture are also outlined.

Obesity is a definitive risk factor of severity and mortality in acute pancreatitis: an updated meta-analysis

BACKGROUND/AIMS

Obesity is considered a risk factor in patients with acute pancreatitis. However, the relationship between obesity and mortality in this disease has not been confirmed definitively even in a previous meta-analysis. Since the publication of our previous meta-analysis, one study has been reported about the prognostic value of obesity in acute pancreatitis. We have performed a new meta-analysis to confirm the relationship between obesity and the outcome of acute pancreatitis.

DATA SOURCES

A MEDLINE search using 'pancreatitis', 'obesity' and 'body mass index' as search terms.

REVIEW METHODS

Clinical studies which investigated the prognostic value of obesity in acute pancreatitis with the following criteria: (a) inclusion of mild and severe acute pancreatitis; (b) use of body mass index (BMI) as the measure of obesity; (c) definition of obesity as BMI >or=30 kg/m(2); (d) definition of severity of acute pancreatitis according to the criteria established in the Atlanta Symposium. Five studies including patients with mild and severe acute pancreatitis and obesity measured by BMI were analyzed. The end points of the meta-analysis were the severity of acute pancreatitis, local complications, systemic complications and mortality. Pooled odds ratio (OR) and confidence intervals (CI) were calculated according to the Mantel-Haenszel method, and heterogeneity was assessed by the multiplicative inverse variance method.

RESULTS

Seven hundred and thirty-nine patients were included. There was no heterogeneity for the variables severity, systemic complications, local complications and mortality among the included studies. Severe acute pancreatitis was significantly more frequent in obese patients (OR 2.9, 95% CI 1.8-4.6). Furthermore, those patients developed significantly more systemic (OR 2.3, 95% CI 1.4-3.8) and especially local complications (OR 3.8, 95% CI 2.4-6.6). In this new analysis, mortality was also higher in obese patients (OR 2.1, 95% CI 1.0-4.8).

CONCLUSION

Obesity is not only a risk factor for the development of local and systemic complications in acute pancreatitis: it also increases the mortality of this disease.

Standardized, unrelated donor cord blood transplantation in adults with hematologic malignancies

The potential role of unrelated donor cord blood transplantation (UD-CBT) in adults remains unclear. This study reports the results of UD-CBT in 22 adults with hematologic malignancies following conditioning with thiotepa, busulfan, cyclophosphamide, and antithymocyte globulin in 21, with thiotepa, fludarabine, and antithymocyte globulin in 1, and graft-versus-host disease (GVHD) prophylaxis with cyclosporine and prednisone. Median age was 29 years (range, 18-46 years), and median weight was 69.5 kg (range, 41-85 kg). HLA match was 6 of 6 in 1 case, 5 of 6 in 13 cases, and 4 of 6 in 8 cases. Median number of nucleated cells infused was 1.71 x 10(7)/kg (range, 1.01 x 10(7)/kg to 4.96 x 10(7)/kg). All 20 patients surviving more than 30 days had myeloid engraftment, and only 1, who received the lowest cell dose, developed secondary graft failure. Median time to reach an absolute neutrophil count of at least 0.5 x 10(9)/L was 22 days (range, 13-52 days). Median time to platelets numbered at least 20 x 10(9)/L was 69 days (range, 49-153 days). Seven patients (32%) developed acute GVHD above grade II, and 9 of 10 patients at risk developed chronic GVHD, which became extensive in 4 patients. Twelve patients remained alive and disease-free 3 to 45 months after transplantation. Disease-free survival (DFS) at 1 year was 53%. Age strongly influenced DFS (P =.01). For patients aged 30 years or younger, the DFS at 1 year was 73%. These preliminary results suggest that UD-CBT should be considered a reasonable alternative in young adults with hematologic malignancy and no appropriate bone marrow donor.

Mesenchymal stem cells from osteoporotic patients produce a type I collagen-deficient extracellular matrix favoring adipogenic differentiation

Mesenchymal stem cells (MSCs), precursor cells resident in the bone marrow, have the capacity to differentiate into bone, cartilage, fat, and connective tissue. We have recently reported that MSCs from "healthy" donors differ from cells obtained from osteoporotic postmenopausal women in their proliferation rate, mitogenic response to osteogenic growth factors, and potential to mineralize. The purpose of this study was to examine the factors that explain the differential capacity of MSCs derived from "healthy" control and osteoporotic postmenopausal women to support mineralization. In addition, we examined the factors that regulate the differentiation of osteoporotic cells into adipocytes. For this purpose, we isolated MSCs from bone marrow of donors and analyzed the synthesis and deposition of type I collagen, the main component of bone extracellular matrix, the time course of gelatinolytic activity expression, the deposition of transforming growth factor beta (TGF-beta), and the ability of cells to differentiate into adipocytes. Our results indicate that cells derived from osteoporotic donors synthesized 50% less type I collagen than normal cells and maintained higher levels of gelatinolytic activity under differentiation conditions (70% versus 15% after 14 days in culture). MSCs derived from osteoporotic women produced 60-65% less TGF-beta and expressed higher adipogenic capacity. We conclude that the capacity of MSCs derived from osteoporotic postmenopausal women to generate and maintain type I collagen-rich extracellular matrix is decreased, favoring their adipogenic differentiation. These observations may explain the decreased mineralization previously observed in these types of cells.

Effect of long-term administration of cross-sex hormone therapy on serum and urinary uric acid in transsexual persons

BACKGROUND

Transsexual persons afford a very suitable model to study the effect of sex steroids on uric acid metabolism.

DESIGN

This was a prospective study to evaluate the uric acid levels and fractional excretion of uric acid (FEUA) in a cohort of 69 healthy transsexual persons, 22 male-to-female transsexuals (MFTs) and 47 female-to-male transsexuals (FMTs). The subjects were studied at baseline and 1 and 2 yr after starting cross-sex hormone treatment.

RESULTS

The baseline levels of uric acid were higher in the MFT group. Compared with baseline, uric acid levels had fallen significantly after 1 yr of hormone therapy in the MFT group and had risen significantly in the FMT group. The baseline FEUA was greater in the FMT group. After 2 yr of cross-sex hormone therapy, the FEUA had increased in MFTs (P = 0.001) and fallen in FMTs (P = 0.004). In MFTs, the levels of uric acid at 2 yr were lower in those who had received higher doses of estrogens (P = 0.03), and the FEUA was higher (P = 0.04). The FEUA at 2 yr was associated with both the estrogen dose (P = 0.02) and the serum levels of estradiol-17beta (P =0.03). In MFTs, a correlation was found after 2 yr of therapy between the homeostasis model assessment of insulin resistance and the serum uric acid (r = 0.59; P = 0.01).

CONCLUSIONS

Serum levels of uric acid and the FEUA are altered in transsexuals as a result of cross-sex hormone therapy. The results concerning the MFT group support the hypothesis that the lower levels of uric acid in women are due to estrogen-induced increases in FEUA.

Randomised trial of endoscopic sphincterotomy with gallbladder left in situ versus open surgery for common bileduct calculi in high-risk patients

BACKGROUND

Morbidity and mortality after surgical treatment of bileduct stones increase with age and associated diseases. A proposed alternative therapy is endoscopic sphincterotomy (ES) with the gallbladder left in situ, and we elected to compare this option with standard open surgery in high-risk patients.

METHODS

98 patients (mean age 80 years) with symptoms likely to be due to bileduct stones or a recent episode of biliary pancreatitis were randomised to be treated either by open cholecystectomy with operative cholangiography and (if necessary) bileduct exploration (n=48) or by endoscopic sphincterotomy alone (n=50).

FINDINGS

The procedure was accomplished successfully in 94% of the surgery group and 88% of the ES group, and there were no significant differences in immediate morbidity (23% vs 16%) or mortality (4% vs 6%). During mean follow-up of 17 months biliary symptoms recurred in three surgical patients, none of whom underwent repeat surgery, and in 10 ES patients, seven of whom had biliary surgery. By multivariate regression analysis endoscopic sphincterotomy was an independent predictor of recurrent biliary symptoms (odds ratio 6.9; 95% Cl 1.46 to 32.54).

INTERPRETATION

In elderly or high-risk patients, surgery is preferable to endoscopic sphincterotomy with the gallbladder left in situ as a definitive treatment for bileduct stones or non-severe biliary pancreatitis.

In-hospital and late results of coronary stents versus conventional balloon angioplasty in acute myocardial infarction (GRAMI trial). Gianturco-Roubin in Acute Myocardial Infarction

One hundred four patients presenting with acute myocardial infarction < 24 hours after onset were randomized to 2 groups: group I (n = 52) was treated with balloon angioplasty followed electively with Gianturco Roubin II stents, and group II was treated with conventional balloon angioplasty alone (n = 52). All lesions were suitable for stenting. Baseline clinical, demographic, and angiographic characteristics were similar in the 2 groups. Procedural success was defined as no laboratory death or emergent coronary bypass, Thrombolysis In Myocardial Infarction (TIMI) trial 2 or 3 flow after the procedure in a culprit vessel, and a residual stenosis < or = 30% for coronary angioplasty and < 20% for stent. Procedural success was 98% in group I versus 94.2% in group II, p = NS. Thirteen patients in group II (25%) had bailout stenting during the initial procedure. Adverse in-hospital events including either death, nonelective coronary bypass, recurrent ischemia, and reinfarction occurred in 3.8% in group I versus 19.2% in group II, p = 0.03. Repeat angiography performed routinely before hospital discharge revealed TIMI 3 flow in the infarct-related artery in 98% in group I versus 83% in group II, p < 0.03. At late follow-up, event-free survival was significantly better in the stent (83%) than in the coronary angioplasty (65%) group (p = 0.002). The procedural in-hospital and late outcomes of this randomized study demonstrate that balloon angioplasty followed electively by coronary stents can be used as the primary modality for patients undergoing coronary interventions for acute myocardial infarction, increasing TIMI 3 flow, reducing in-hospital adverse events, and improving late outcome compared with balloon angioplasty alone.

Some kinetic properties of a cysteine proteinase (cruzipain) from Trypanosoma cruzi

A cysteine proteinase, purified to homogeneity from epimastigotes of Trypanosoma cruzi, was strongly inhibited by L-trans-epoxysuccinylleucylamido(4-guanidino)butane (E-64). The second-order rate constant was 20,800 M-1.s-1, and the reagent could be used for active site titration. The enzyme hydrolysed chromogenic peptides at the carboxyl Arg or Lys; it required at least one more amino acid, preferably Arg, Phe, Val or Leu, between the terminal Arg or Lys and the amino-blocking group. Enzyme activity on azocasein at pH 5.0 was increased by urea, maximal activity being attained at 2 M, and was still as active at 5 M urea as in its absence. Guanidine hydrochloride and KSCN also activated at low concentrations, but caused a strong inhibition above 2 M and 1 M, respectively. When azocasein was tested as a substrate at pH 7.0, there was no activation, and when synthetic substrates were used all chaotropic agents tested were inhibitory. The results suggest that the enzyme, for which we propose the trivial name 'cruzipain', differs in some aspects from all other cysteine proteinases described so far, although it shares several of the properties of mammalian cathepsin L.

Impaired mitochondrial oxidative phosphorylation in the peroxisomal disease X-linked adrenoleukodystrophy

X-linked adrenoleukodystrophy (X-ALD) is an inherited metabolic disorder of the nervous system characterized by axonopathy in spinal cords and/or cerebral demyelination, adrenal insufficiency and accumulation of very long-chain fatty acids (VLCFAs) in plasma and tissues. The disease is caused by malfunction of the ABCD1 gene, which encodes a peroxisomal transporter of VLCFAs or VLCFA-CoA. In the mouse, Abcd1 loss causes late onset axonal degeneration in the spinal cord, associated with locomotor disability resembling the most common phenotype in patients, adrenomyeloneuropathy. We have formerly shown that an excess of the VLCFA C26:0 induces oxidative damage, which underlies the axonal degeneration exhibited by the Abcd1(-) mice. In the present study, we sought to investigate the noxious effects of C26:0 on mitochondria function. Our data indicate that in X-ALD patients' fibroblasts, excess of C26:0 generates mtDNA oxidation and specifically impairs oxidative phosphorylation (OXPHOS) triggering mitochondrial ROS production from electron transport chain complexes. This correlates with impaired complex V phosphorylative activity, as visualized by high-resolution respirometry on spinal cord slices of Abcd1(-) mice. Further, we identified a marked oxidation of key OXPHOS system subunits in Abcd1(-) mouse spinal cords at presymptomatic stages. Altogether, our results illustrate some of the mechanistic intricacies by which the excess of a fatty acid targeted to peroxisomes activates a deleterious process of oxidative damage to mitochondria, leading to a multifaceted dysfunction of this organelle. These findings may be of relevance for patient management while unveiling novel therapeutic targets for X-ALD.

Is obesity a risk factor in acute pancreatitis? A meta-analysis

BACKGROUND/AIMS

Obesity has been associated with a worse prognosis in acute pancreatitis. According to some authors, obesity favours the development of local complications, while according to other reports obese patients presented more frequently systemic complications. Few studies find a relationship between obesity and mortality in acute pancreatitis. We conducted a meta-analysis of several reports that evaluate the relationship between obesity and the outcome of acute pancreatitis in order to assess its prognostic role in this disease.

METHODS

A MEDLINE search was conducted from 1965 to December 2002 with search terms including obesity, body mass index (BMI) and pancreatitis. A total of 12 reports were identified. Of these, only four studies included patients with mild and severe acute pancreatitis and measured obesity by BMI. The end points of the meta-analysis were the severity of acute pancreatitis, local complications, systemic complications and mortality. Obesity was defined when BMI was > or =30 kg/m2. Pooled odds ratio (OR) and confidence intervals (CI) were calculated according to the Mantel-Haenszel method, and heterogeneity was assessed by the multiplicative inverse variance method.

RESULTS

A total of 607 patients were evaluated. There was no heterogeneity for the variables severity, systemic complications, local complications and mortality among the included studies. Severe AP was significantly more frequent in obese patients (OR 2.6, 95% CI 1.5-4.6). Furthermore, those patients developed significantly more systemic (OR 2.0, 95% CI 1.1-4.6) and local complications (OR 4.3, 95% CI 2.4-7.9). Mortality in obese patients was only slightly higher (OR 1.3, 95% CI 0.5-3.6).

CONCLUSION

Obesity is a prognostic factor favouring the development of systemic and local complications in this disease. Therefore, it should be used routinely as part of the initial assessment of the severity of a case of acute pancreatitis.

Acute promyelocytic leukemia. Therapy results and prognostic factors

From December 1976 to July 1986, 34 patients with acute promyelocytic leukemia (APL) were treated with daunorubicin (DNR) alone and simultaneous supportive therapy with low-dose heparin, platelet transfusions, and fresh frozen plasma. Two consecutive maintenance therapy regimens were employed in patients who achieved complete remission (CR): (1) a classical maintenance with methotrexate and 6-mercaptopurine, with DNR plus methyl-GAG re-inductions; (2) from 1982 an intensive sequential combination therapy regimen was administered. CR was achieved in 23 patients (68%). Only one patient had leukemic resistance. Other failures were a consequence of post-chemotherapy complications. A multivariate logistic regression analysis has been performed to evaluate the prognostic importance on response to remission induction of 25 patient and disease characteristics at diagnosis. The significant variables in decreasing order of significance were: serum albumin level, fever at diagnosis, serum creatinine level, and age. The median duration of remission and survival by Kaplan-Meier analysis were projected to be 24 and 25 months, respectively. Relapses occurred in 11 of 23 CR patients. Nine patients remained in the first remission from 5+ to 37+ months. Short-term (CR) and long-term results (duration of remission and survival) in APL treated for induction with DNR alone were similar to those obtained in other subtypes of acute myeloblastic leukemia by intensive combination chemotherapy.

Early infections in adult patients undergoing unrelated donor cord blood transplantation

Early transplant-related mortality after cord blood transplantation from unrelated donors (UD-CBT) is close to 50%, mainly due to infectious complications. We have studied the incidence and characteristics of early infections (before day 100) in a series of 27 adult patients (median age 30 years, range 16-46) undergoing UD-CBT at a single institution. All 27 patients experienced at least one infectious episode and 18 (66%) suffered a severe infection. Bacteremia occurred in 55% of patients (13 with Gram-positive and 11 with Gram-negative microorganisms). Eleven of 19 CMV-seropositive patients (58%) developed CMV antigenemia and one patient had CMV disease. Fungal infections were documented in three patients (11%), comprising invasive fungal infections in two cases and a localized esophagitis in one. Ten patients (37%) died before day 100 after transplantation. Infection was considered the primary cause of death in four patients (sepsis by Acinetobacter spp. bacteremia in three cases) and contributed to death in another four. The most striking findings in this series were the high incidence of, and mortality due to multiresistant Acinetobacter spp. and the low incidence of and lack of mortality due to CMV disease. This report confirms that infection is a major complication in adults undergoing UD-CBT.

Efficacy and tolerance of interferon-alpha(2b) in the treatment of chronic hepatitis C virus infection in haemodialysis patients. Pre- and post-renal transplantation assessment

BACKGROUND

Hepatitis C virus (HCV) infection represents an important problem for the dialysis population due to its high prevalence and the long-term development of chronic liver disease, particularly following renal transplantation.

METHODS

In order to assess the efficacy and tolerance of interferon (IFN) in the treatment of chronic hepatitis C in haemodialysis (HD) patients and their clinical course following renal transplantation, a multicentre, randomized, open-label study was conducted to compare IFN therapy vs a control group.

RESULTS

Nineteen HCV RNA-positive patients received 3 x 10(6) U of IFN s.c., three times a week (post-HD), and 17 HCV RNA-positive patients were assigned to the control group. Tolerance to IFN therapy was good in nine patients, while treatment was discontinued in the other 10 due to the occurrence of side effects. HCV RNA was negative at the end of treatment in 14 out of 19 patients (74%) receiving IFN and in one patient (5%) in the control group. Six out of the 14 patients who initially responded to IFN therapy had a virological relapse (43%). Eight patients (42%) remained HCV RNA-negative, three of them until the day that renal transplantation (RT) was performed (7, 12 and 27 months, respectively), as did five patients on HD during the follow-up (27+/-5 months). Eight out of the nine patients (89%) who completed therapy were HCV RNA-negative at the end of treatment, and seven of them (78%) remained HCV RNA-negative during the follow-up on dialysis (21+/-8 months). Mean transaminase (ALT) values were significantly decreased following IFN therapy, while no changes were observed during the follow-up period in the control group. Fifteen patients (10 in the treatment group and five in the control group) underwent RT. Three patients in the treatment group were HCV RNA-negative at RT, and one of them had a virological relapse 20 months after RT, while the other two remained HCV RNA-negative at 3 months and 24 months after RT, respectively. In contrast to the control group, transaminase (ALT) remained within normal limits in all patients in the treatment group. Finally, during the post-RT follow-up, the transaminase mean values were significantly lower in treated patients vs patients in the control group (P<0.05).

CONCLUSIONS

It is concluded that the biochemical and virological response to IFN therapy is good in HD patients. In addition, IFN therapy appears to exert a beneficial effect on the course of liver disease following RT, regardless of the virological response. Despite the fact that IFN therapy was discontinued in 10 out of the 19 patients due to the occurrence of side effects, these disappeared following discontinuation of therapy. Therefore, IFN therapy is advisable for HCV-infected dialysis patients who are candidates for RT.

Factors predicting mortality in severe acute pancreatitis

Acute pancreatitis (AP) is a common disorder in which ensuing serious complications may lead to a fatal outcome in patients.

BACKGROUND/AIMS

To describe a large series of patients with severe AP (SAP) who were admitted to our hospital and to identify factors predicting mortality.

PATIENTS AND METHODS

In a retrospective study, all patients with SAP diagnosed between February 1996 and October 2000 according to the Atlanta criteria were studied.

RESULTS

Out of a total of 363 AP patients, 67 developed SAP. The mean age of the patients was 69; the commonest etiology was biliary; 55.2% developed necrosis; the commonest systemic complication was respiratory failure (44.7%), followed by acute renal failure (35.8%) and shock (20.9%). A total of 31.3% of the patients died. Factors significantly related to mortality were age, upper digestive tract bleeding, acute renal failure, respiratory failure and shock by univariate analysis. However, pseudocysts seemed to have a protective effect. By multivariate analysis, independent prognostic factors were age, acute renal failure and respiratory failure.

CONCLUSIONS

Patients with SAP mainly died due to systemic complications, especially acute renal failure and respiratory failure. Necrosis (in the absence or presence of infection) was not correlated with increased mortality. A pseudocyst was found to be a protective factor, probably because the definition itself led to the selection of patients who had survived multiorgan failure.

Changes in Volatile Compounds during Ripening in Grapes of Airén, Macabeo and Chardonnay White Varieties Grown in La Mancha Region (Spain)

Changes in volatile compounds in musts and skins of grapes of Airén, Macabeo and Chardonnay white varieties were determined during ripening. The musts of the Airén variety contained higher concentrations of c-3-hexenol; musts of the Macabeo variety were the richest in t-3-hexenol and 2,4-hexadienal, while the Chardonnay musts stood out for having higher concentrations of benzaldehyde, phenylacetaldehyde and benzyl alcohol. The skins of the three varieties were both qualitatively and quantitatively richer in volatiles than were the musts. The skins of the Airén grapes had the highest levels of nerol. Airén grapes were the only variety in which citronellol was present in the skins. Low concentrations of eugenol were detected in the skins of the Chardonnay grape variety but were not present in the other two varieties. Changes in the concentration of the volatile compounds during ripening were not uniform; this made difficult the determination of the optimum level of ripening for each variety on the basis of the volatile compound content. Nevertheless, results indicated that C6 compounds and terpene concentrations reached a maximum at 6-8 ° Baumé in the Airén grapes and at around 11 ° Baumé in the Chardonnay and Macabeo grapes.

Role of Ca2+-independent phospholipase A2 on arachidonic acid release induced by reactive oxygen species

Previous studies have shown that reactive oxygen species (ROS) enhance arachidonic acid (AA) release and the subsequent AA metabolism in macrophages. The purpose of this study was determined the implication of phospholipases A2 (PLA2s) in these events. Our results show that oxidative stress induced by exogenous adding of hydrogen peroxide or superoxide anion in macrophage RAW 264.7 and mouse peritoneal macrophage cultures caused a marked enhancement of calcium-independent PLA2 (iPLA2) activity,whereas the increment of secreted PLA2 (sPLA2) and calcium-dependent cytosolic PLA2 (cPLA2) activities were slight. This increase of iPLA2 activity by ROS was rapid and dose-dependent. ROS also induced a significant [3H] arachidonic acid (AA) release. The iPLA2 selective inhibitor, bromoenol lactone, almost completely suppressed the mobilization of [3H]AA induced by ROS whereas antisense oligonucleotide against cPLA2 did not have any appreciable effect. Thus, our data show that iPLA2 activity is involved in the mechanism by which ROS increases the availability of free AA in macrophages RAW 264.7. Moreover, the protein kinase C (PKC) inhibitor, calphostin C, and calcium chelators had no effect on the [3H]AA release induced by ROS, suggesting this is a regulatory role of iPLA2.

Identification of genes involved in imatinib resistance in CML: a gene-expression profiling approach

The use of the tyrosine kinase inhibitor imatinib, which blocks the enzymatic action of the BCR-ABL fusion protein, has represented a critical advance in chronic myeloid leukemia (CML) treatment. However, a subset of patients initially fails to respond to this treatment. Use of complementary DNA (cDNA) microarray expression profiling allows the identification of genes whose expression is associated with imatinib resistance. Thirty-two CML bone marrow samples, collected before imatinib treatment, were hybridized to a cDNA microarray containing 6500 cancer genes, and analyzed using bootstrap statistics. Patients refractory to interferon-alpha treatment were evaluated for cytogenetic and molecular responses for a minimum of 12 months. A set of 46 genes was differentially expressed in imatinib responders and non-responders. This set includes genes involved in cell adhesion (TNC and SCAM-1), drug metabolism (cyclooxygenase 1), protein tyrosine kinases and phosphatases (BTK and PTPN22). A six-gene prediction model was constructed, which was capable of distinguishing cytogenetic response with an accuracy of 80%. This study identifies a set of genes that may be involved in primary resistance to imatinib, suggesting BCR-ABL-independent mechanisms.

Rethinking human resources: an agenda for the millennium

Health care reforms require fundamental changes to the ways in which the health workforce is planned, managed and developed within national health systems. While issues involved in such transition remain complex, their importance and the need to address them in a proactive manner are vital for reforms to achieve their key policy objectives. For a start, the analysis of human resources in the context of health sector appraisal studies will need to improve in depth, scope and quality by incorporating functional, institutional and policy dimensions.

Effects of proteinase inhibitors on the growth and differentiation of Trypanosoma cruzi

Three proteinase inhibitors, one peptidyl acyloxymethyl ketone (AMK), Z-Phe-Lys-CH2-OCO-(2,4,6-Me3)Ph.HCl, and two diazomethyl ketones (DMKs), Z-Phe-Phe-DMK and Z-Phe-Ala-DMK, have been studied for their effects in vitro on the four developmental stages of Trypanosoma cruzi. The three inhibitors penetrated living parasites and inhibited the major cysteine proteinase, cruzipain. The AMK was the most potent inhibitor of cruzipain itself and at 20 microM caused lysis of epimastigotes and trypomastigotes. When at lower concentrations, however, it had little effect on epimastigote growth but reduced metacyclogenesis. The DMKs had no effect against epimastigotes but inhibited differentiation to metacyclics. All three inhibitors markedly reduced infection of Vero cells by the parasite and the multiplication of the intracellular amastigotes, whereas release of trypomastigotes was almost entirely prevented. The results confirm the importance of cysteine proteinases in the life cycle of T. cruzi, and suggest that the differentiation steps are the most susceptible to cysteine proteinase inhibitors.

A prospective study of astrovirus diarrhea of infancy in Mexico City

AIM

To describe the epidemiologic and clinical characteristics of astrovirus-associated diarrhea in a cohort of young children from a periurban community in Mexico City.

METHODS

From November, 1988, through December, 1991, a total of 214 children were enrolled in a longitudinal study of diarrhea and monitored from birth to 18 months of age. A stool specimen was collected during each episode of diarrhea. Specimens from a total of 510 diarrhea episodes were tested for astrovirus by enzyme immunoassay and examined for other enteric pathogens. The antigenic types of astrovirus were determined by a typing enzyme immunoassay.

RESULTS

Astrovirus was detected in 26 (5%) of 510 diarrhea episodes, with an incidence rate of 0.1 episode/child year; the highest rate was in children 13 to 18 months of age. Astrovirus-associated diarrhea was characterized by a median of 4 stools (range, 2 to 10) during the first 24 h, a median duration of 3 days (range, 1 to 21), vomiting (20%), and fever (7%). No cases of dehydration or repeat symptomatic infections were observed. Coinfection with another pathogen was detected in 11 of the 26 episodes (42%). Serotype 2 (35%) was most common, followed by serotypes 4 (15%), 3 (11%), and 1 and 5 (4% each); 31% were nontypable. Astrovirus-associated diarrhea was less severe, as measured by the number of stools (4.3 +/- 1.9), than diarrhea caused by rotavirus (7.1 +/- 2.8) or when coinfections occurred (5.5 +/- 1.6; P = 0.008).

CONCLUSIONS

Astrovirus was associated with 5% of the episodes of diarrhea in this cohort of young Mexican children and presented as a mild secretory diarrhea. Five predominant antigenic types were detected with type 2 being the most common.

Epidemiological Study of Non-systemic Parasitism in Dogs in Southeast Mediterranean Spain Assessed by Coprological and Post-mortem Examination

The prevalence and risk factors of non-systemic canine ecto- and endoparasitism and anthelminthic use in Murcia located at the centre of the Spanish Mediterranean coastal arch, was investigated by coprology and necropsy in up to 275 pet, city shelter and stray dogs in 2001-2004. Faecal parasite stages were detected in 25% of dogs. Species frequency was 6-10% for Toxocara canis, Ancylostomatidae spp., Toxascaris leonina and Isospora canis, and 0.4-1% for Trichuris vulpis, Giardia lamblia, and Dipylidium caninum. Logistic regression indicated that the risk of intestinal parasitism was highest for dogs <or=1 year old, in the middle to low weight range and kept at the city shelter. Although risk factors varied according to the species, T. canis was most common in <1 year old and Ancylostomatidae spp. was more prevalent in older dogs. This suggests that the dominant species was Uncinaria spp. and not the more zoonotically important Ancylostoma spp. This was further supported by necropsy findings; however, the degree of agreement between post-mortem and coprological examination for intestinal parasites was generally poor. Necropsy revealed 10%G. lamblia, 12%Taenia spp. 38%D. caninum infections. Fleas, ticks and lice were also found in 38%, 6% and 2% of necropsied stray dogs. These results demonstrate the need for an urgent parasite control programme at the city dog shelter and the need to improve the owner's education on zoonotic risks, the proper use of anthelminthics, and other parasite control practices.