Percolation-based risk index for pathogen invasion: application to soilborne disease in propagation systems.

Propagation systems for seedling growth play a major role in agriculture, and in notable cases (such as organic systems), are under constant threat from soil and seedborne fungal plant pathogens such as Rhizoctonia solani or Pythium spp. Yet, to date little is known that links the risk of disease invasion to the host density, which is an agronomic characteristic that can be readily controlled. We introduce here, for the first time in an agronomic system, a percolation framework to analyze the link. We set up an experiment to study the spread of the ubiquitous fungus R. solani in replicated propagation systems with different planting densities, and fit a percolation-based epidemiological model to the data using Bayesian inference methods. The estimated probability of pathogen transmission between infected and susceptible plants is used to calculate the risk of invasion. By comparing the transmission probability and the risk values obtained for different planting densities, we are able to give evidence of a nonlinear relationship between disease invasion and the inter-plant spacing, hence to demonstrate the existence of a spatial threshold for epidemic invasion. The implications and potential use of our methods for the evaluation of disease control strategies are discussed.

Left Atrial Appendage Exclusion in Atrial Fibrillation Radiofrequency Ablation during Mitral Valve Surgery: A Single-Center Experience.

BACKGROUND: Atrial fibrillation surgical radiofrequency ablation (AFSA) during mitral valve surgery (MVS) has almost completely superseded the Cox-Maze procedure for the treatment of atrial fibrillation. METHODS: We retrospectively analyzed 100 patients who underwent MVS + AFSA in our institution from January 2008 to June 2017. We compared the effectiveness of AFSA in patients who underwent LAA exclusion to those who did not. Moreover, we analyzed the role of preoperative AF duration (≤ or >1 year) and medial-lateral left atrial dimensions (ML-LAD) (≤ or >6 cm). The efficacy endpoint was freedom from AF at discharge and at 2-year follow-up. The safety endpoints were need of a permanent pacemaker (PMK), surgical re-exploration, occurrence of stroke, and left circumflex artery or esophageal lesions. RESULTS: Overall, the rate of AF freedom was 69% at discharge and 80% at 2-year follow-up. LAA exclusion did not influence AF freedom at 2-year follow-up, and 84.6% of patients who underwent LAA exclusion were in the sinus rythm (SR) at 2 year compared to 75% of those who did not receive LAA exclusion free from AF as well (p=0.230). AF duration ≤1 or >1 year did not influence sinus rhythm (SR) maintenance (85.7% vs. 75.8%; p=0.224), and in these two groups, LAA exclusion did not change the efficacy of AFSA. ML-LAD ≤ 6 cm was associated with better results in terms of SR maintenance. A statistically significant association between LAA exclusion and SR maintenance at 2-year follow-up (p=0.017) was found among patients with ML-LAD ≤ 6 cm. Complications included 7 cases of PMK implantation, 2 cases of surgical re-exploration, and 1 case of stroke. No circumflex artery or esophageal lesions occurred after surgical procedures. CONCLUSIONS: In our experience, AFSA during isolated MVS resulted in good outcomes in terms of SR maintenance and incidence of complications. AF duration ≤ 1 year did not influence results, while patients with ML-LAD ≤ 6 cm had significantly better results regarding SR at follow-up. In patients with ML-LAD ≤ 6 cm, LAA exclusion significantly increased the success rate of SR maintenance at 2-year follow-up.

[Tuberculous peritonitis in HIV-infected patients]. / Peritonitis tuberculosa en pacientes infectados por el virus de la inmunodeficiencia humana.

UNLABELLED: In order to describe the clinical and laboratory findings of Mycobacterium tuberculosis peritonitis M. tuberculosis in HIV+ patients, we conducted a retrospective analysis of the medical records of HIV+ patients with isolation of M. tuberculosis from ascitic fluid (AF), assisted at Hospital Muñiz, Buenos Aires, Argentina (1996-2005). RESULTS: 21 patients were included. Median age: 33, male sex: 52%; peripheral blood CD4-T lymphocyte count (median): 85/mm3; prior history of tuberculosis: 40%; cirrhosis: 65%; enolism: 45%; HCV coinfection: 85%. The most frequent symptoms were abdominal distension (71%), fever (62%) and abdominal pain (19%). The chemical characteristics of the AF were (median): leukocyte count: 751/mm3 (mononuclear predominance: 79%), protein: 3.1 g/dl, LDH: 351 IU/l. AF samples positive for acid fast bacilli at direct microscopic examination: 14%. Infection with multidrug resistant M. tuberculosis (TB-MR): 20%. M. tuberculosis was isolated from other clinical samples in 79%. Fifteen patients received treatment for tuberculosis; in 30% of cases, it was not appropriate due to the susceptibility of the isolated strain. Overall mortality was 66.4%. CONCLUSION: high mortality was observed, which may be attributable to the high frequency of TB-MR, the level of immunosuppression and the prevalence of cirrhosis secondary to enolism and/or HCV coinfection.

Tuberculous meningitis in HIV-infected and non-infected patients: comparison of cerebrospinal fluid findings.

We performed a retrospective comparison of cerebrospinal fluid (CSF) characteristics and drug susceptibility profile in human immunodeficiency virus (HIV) infected and non-infected patients with a diagnosis of tuberculous meningitis. HIV-infected patients had a higher frequency of non-inflammatory CSF (absence of pleocytosis) and of infection by multidrug-resistant strains of Mycobacterium tuberculosis. Protein CSF levels were lower in HIV-infected patients, while and glucose concentration was similar in both groups. Hospital mortality was significantly higher in HIV-infected patients (63.3% [64/101] vs. 17.5% [7/40]).

Cervical length and maternal factors in expectantly managed prolonged pregnancy: prediction of onset of labor and mode of delivery.

OBJECTIVE: To examine the value of combining cervical length and maternal characteristics in a prolonged-pregnancy clinic in the prediction of the probability of firstly, spontaneous onset of labor within the subsequent 10 days and secondly, the need for Cesarean section. METHODS: This was a prospective study of women with singleton pregnancies attending an ultrasound-based prolonged-pregnancy clinic at 40 + 4 to 41 + 6 weeks of gestation. The policy was to delay induction of labor by 7-10 days unless there was evidence of a specific medical or obstetric indication or the mother wanted earlier delivery. The measurement of cervical length was not given to the obstetrician, midwife or patient. Regression analysis was used to determine which of the following factors had a significant contribution in predicting induction of labor: maternal age, body mass index (BMI), ethnic origin, parity and cervical length. Regression analysis was also used to determine which of the factors amongst the maternal characteristics, onset of labor and cervical length provided significant prediction of Cesarean section. RESULTS: We examined 2316 pregnancies but we excluded from further analysis 452 (19.5%) cases because iatrogenic delivery was carried out within the subsequent 6 days, including 427 cases of induction of labor (340 at the request of the mother and 87 for medical indications) and 25 cases of Cesarean section. In the remaining 1864 cases there was spontaneous onset of labor and delivery within 10 days in 1536 (82.4%) and induction of labor in 7-10 days in 328 (17.6%). The rate of Cesarean section was 15.2% (233 of 1536) in those with spontaneous onset of labor and 36.0% (118 of 328) in those whose labor was induced. Regression analysis demonstrated that in the prediction of induction of labor there were significant contributions from cervical length, BMI, parity and gestational age, and in the prediction of Cesarean section there were significant contributions from onset of labor, cervical length, BMI, parity and ethnicity. CONCLUSION: Ultrasonographic measurement of cervical length at 41 weeks together with maternal factors can define the patient-specific probability of spontaneous onset of labor in the subsequent week and the risk of Cesarean section.

Prenatal diagnosis and outcome of echogenic fetal lung lesions.

OBJECTIVE: To describe the antenatal findings and outcome of fetuses with echogenic lung lesions. METHODS: This was a retrospective study of the prenatal sonographic features, antenatal management and outcome of 193 fetuses with an echogenic lung lesion diagnosed at 18-35 weeks of gestation. There were nine cases of congenital high airway obstruction syndrome (CHAOS), 170 cases of cystic adenomatoid malformation (CAM) and 14 cases of pulmonary sequestration (PS). A literature search was also carried out to compare our data with those of previous series. RESULTS: The prognosis in our series of fetuses with CHAOS was invariably poor, but the literature describes a handful of survivors after delivery by Cesarean section and ex-utero intrapartum therapy (EXIT). Of the cases in our series with PS and no pleural effusions, more than 95% survived; in half of these cases the lesion resolved antenatally and in the other half sequestrectomy was carried out postnatally. In cases with PS and pleural effusions, successful treatment was provided by the placement of thoracoamniotic shunts or occlusion of the feeding blood vessel by ultrasound-guided laser coagulation or injection of sclerosants. In cases with CAM and no hydrops, there was more than 95% survival and in up to half of the cases there was sonographic evidence of spontaneous antenatal resolution of the hyperechogenic lesion, which was confirmed by postnatal imaging in about 60% of the cases. Of the cases with CAM with hydrops managed expectantly, more than 95% died before or after birth. Of the cases with macrocystic CAM with hydrops, two-thirds survived after placement of a thoracoamniotic shunt. In cases with microcystic CAM with hydrops, there is some evidence that open fetal surgery with lobectomy could improve survival but such treatment is highly invasive for the mother. CONCLUSIONS: CHAOS is a severe abnormality, whereas CAM and PS are associated with a good prognosis. In a high proportion of fetuses with hyperechogenic lung lesion, there is spontaneous antenatal resolution and the underlying pathology may be transient bronchial obstruction.

[Mycobacterium bovis tuberculosis in a female patient with AIDS]. / Tuberculosis por Mycobacterium bovis en una mujer con SIDA.

M. bovis, the agent of bovine tuberculosis, was in other times, the main ethiological agent of tuberculosis (TBC) in industrialized countries. At the moment, the human cases have become not very frequent, except in those countries where the illness is even endemic. In patients with immunodeficiency syndrome, it usually presents as a systemic illness. We present the case of a woman with AIDS and disseminated TBC caused by M. bovis. The isolated micobacteria turned out to be resistant to rifampin and pyrazinamide. She was treated with isoniazid, ethambutol and ofloxacin with good clinical evolution. This case turned out to be the first isolation of M. bovis in a patient with AIDS, in Muñiz hospital.

Three-dimensional cultures of normal human osteoblasts: proliferation and differentiation potential in vitro and upon ectopic implantation in nude mice.

We report the establishment in vitro of three-dimensional (3D) cultures of human osteoblasts (hOB) derived from normal adults and supported uniquely by the extracellular matrix (ECM) they deposit. Osteoblasts were cultured in 3D cultures in vitro for up to 120 days. The 3D cultures, examined at 25, 31, and 48 days, expressed protein markers of osteoblastic cells, namely osteonectin, collagen type I, fibronectin, osteopontin, bone sialoprotein, biglycan, and decorin. Sequentially, alkaline phosphatase (AP) and then Ca incorporation, mineralization of matrix (monitored by histochemistry and transmission electron microscopy), and finally osteocalcin expression, were detected in the 3D cultures. Ultrastructurally, morphology progressed from early to mature osteoblast and to osteocyte-like. Cells were embedded in a matrix with organized collagen type I fibers containing, increasingly with time of culture, needle-shaped crystals, often associated with matrix vesicles, characteristic of those in bone. During the culture (up to 120 days) there was an outgrowth of proliferating osteogenic cells from the 3D structure. Subcutaneous implantation in nude mice for 20 days of osteoblasts cultured in 3D culture for different lengths of time in vitro, showed progression of mineralization from the inner region of the implant outward, with peripheral cells being embedded in nonmineralized, collagen-rich matrix. The 3D implants were invaded by vessels derived from the host.

Malignant lymphoma involving the mandible. Clinical, morphologic, and immunohistochemical study of 17 cases.

We present 17 cases of non-Hodgkin's lymphoma of the mandible, collected over a span of 10 years. Clinically, the patients showed a male:female ratio of 1:2.4 and a mean age of 60.6 years. Swelling was the most common symptom. In 11 of 17 patients, the disease presented in stage I. Radiotherapy alone was employed in 11 patients, in conjunction with chemotherapy in 5 patients, and was preceded by surgery in the remaining case. At this writing ten of the subjects are still alive, five died following progression of the disease, and two were lost during follow-up while in complete remission. Histopathology revealed 15 B-cell lymphomas (1 centroblastic/centrocytic, nine centroblastic, one Burkitt's, two immunoblastic, and two lymphoblastic) and two peripheral T-cell lymphomas (pleomorphic). The above diagnoses were confirmed by immunohistochemical analysis with a wide panel of reagents against fixative-resistant molecules. Our data suggest that (a) lymphomas of the mandible are principally represented by high-grade B-cell varieties (88%); (b) primitive T-cell lymphomas (here documented for the first time) have the same incidence in the mandible as they have in lymph nodes; and (c) immunohistochemistry, besides confirming histogenetic interpretations based on morphologic findings, provides the key to the differential diagnosis from malignant large-cell nonlymphoid tumors.

Beta-HCG aberrant expression in primary mediastinal large B-cell lymphoma.

We report on a primary mediastinal large B-cell lymphoma with aberrant expression of beta-human chorionic gonadotropin (beta-hCG). The patient, a 33-year-old man, had cough, dyspnea, fever, superior vena cava syndrome, and a mediastinal bulky tumor. A biopsy showed that the latter was characterized by large cells, sclerosis, and compartmentalization. The neoplastic elements expressed CD45, CD20, CD79a and, partially, CD30, whereas they were negative for CD3, epithelial membrane antigen and cytokeratins. Surprisingly, they displayed a clear-cut positivity for beta-hCG. The remaining oncofetal markers applied (PLAP and alpha1-fetoprotein) were negative. Electron microscopy demonstrated the presence of numerous nuclear pockets and the lack of intercellular junctions. DNA analysis by polymerase chain reaction showed clonal rearrangement of Ig heavy-chain genes. The patient responded promptly to the administration of MACOP-B. To the best of our knowledge, this is the first example of B-cell lymphoma showing positivity for beta-hCG; a similar aberrant expression was previously observed only in three Japanese patients with human T-cell lymphotropic virus type I+ adult T-cell lymphoma/leukemia. Because primary mediastinal large B-cell lymphoma has in the past been frequently confused with germ cell tumors, pathologists should be aware of possible beta-hCG expression by lymphomatous cells to avoid the risk of misdiagnosis.

Placental calcification: a metastatic process?

Placental calcification commonly increases with gestational age. The mechanism of apatite mineralization probably involves one of three known mechanisms of tissue calcification: physiological (like bone), dystrophic (ischaemia-related) or metastatic (mineralization in a supersaturated environment). This study was designed to determine the mechanism of calcification by examining (1) the mineral content of placental calcifications in comparison to other physiological and pathological apatites, and (2) the expression of bone morphogenetic proteins (BMPs), which are important in physiological calcification, across gestational age. By energy-dispersive x-ray analysis (EDXA), the Ca/P weight ratio for apatitic mineral from mature calcifications was 2.00+/-0.05 (s.e.), which is similar to that for stones formed in a metastatic, supersaturated environment and lower than that observed in physiological calcification. Biologically active BMP, which was determined by bioassay, was demonstrated in mature and postmature placentae. The BMPs PLAB, PDF and related protein INSL-4 were identified by semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR), but their mRNA expression was independent of gestational age (7-41 weeks of gestation). We conclude that (1) the identified BMPs were not related directly to placental calcification, which argues against physiological calcification, and (2) the chemical composition of the apatitic mineral was suggestive of rapid formation in a supersaturated environment, which is consistent with a metastatic mechanism of calcification.

Variable expression of leucocyte-common (CD45) antigen in CD30 (Ki1)-positive anaplastic large-cell lymphoma: implications for the differential diagnosis between lymphoid and nonlymphoid malignancies.

Monoclonal antibodies (mAbs) directed against the leucocyte common (CD45) antigen have been proposed as a useful tool for the differential diagnosis between malignant lymphomas (CD45+) and poorly differentiated nonhemopoietic tumors (CD45-). Thanks to the availability of mAbs directed against fixative-resistant epitopes of the CD45 molecule, this distinction can now easily be made even in routinely processed tissues. However, a small percentage of morphologically poorly defined neoplasms are difficult to diagnose even with the help of immunohistochemistry. The investigators report that 63 out of 165 anaplastic large-cell (ALC) lymphomas did not show any reactivity for the CD45 antigen in paraffin sections. In routine biopsies, the lymphomatous nature of these cases, most of which had been sent for consultation, could be always unequivocally established by demonstrating negativity for cytokeratins (mAb KL1) and clear dot-like and/or surface reactivity with the Ber-H2 mAb, which is directed against a fixative-resistant epitope of the lymphoid cell activation antigen CD30. Strikingly, 54% of the CD45-cases reacted with mAbs directed against fixative-resistant epitopes of the T cell-restricted CD45RO antigen (mAb UCHL1) or the B-restricted molecules CD45RA (mAb 4KB5) and L26 (unclustered). In order to avoid confusion of ALC lymphomas with anaplastic nonlymphoid tumors, pathologists must be aware of the existence of CD30+/CD45- ALC lymphomas, as they can mimic the above-mentioned malignancies both morphologically (due to the sinusoidal growth pattern) and phenotypically (due to the expression of EMA). The investigators conclude that the combined use of mAbs directed against fixative-resistant epitopes of the CD30, CD45RO, CD45RA, and L26 antigens and cytokeratins is essential for the correct diagnosis and treatment of these equivocal cases.

An unusual marrow transplant complication: cardiac myxoma.

We report a right atrial myxoma which suddenly developed in a thalassemic patient after allogeneic bone marrow transplantation. The tumor was first detected by echocardiography on day +47 after transplant and the patient underwent surgical removal of the myxoma on day +103. The post-operative course was uneventful, and at more than 3 years from the event, he is alive and well, cured from his congenital disease, with no detectable intra-cardiac tumor. The onset of the myxoma in the early post-transplant period and the extremely high velocity of growth suggest a possible relationship of this condition with the immunosuppressive status.

Centrocytic-like lymphoma associated with localized amyloidosis of the large intestine.

A case of low-grade centrocytic-like (CCL) B-cell lymphoma involving the large intestine, the regional lymph nodes and the spleen is reported. In the large intestine the lymphomatous infiltrate was restricted to sites of intense antigenic stimulation (diverticula, appendix, ileo-caecal valve) and was associated with marked plasma cell differentiation and massive amyloid deposits. The immunophenotype was CD20, CD21, CD45RA/MB1/MT2, CD68, CD45 related/Ki-B3 and HLA-DR positive, and MB2, DBA.44 reactive regarding the CCL cell lymphoma subpopulation; and IgG-lambda positive regarding its plasma cell fraction.

The EnVision++ system: a new immunohistochemical method for diagnostics and research. Critical comparison with the APAAP, ChemMate, CSA, LABC, and SABC techniques.

AIM: To assess a newly developed immunohistochemical detection system, the EnVision++. METHODS: A large series of differently processed normal and pathological samples and 53 relevant monoclonal antibodies were chosen. A chessboard titration assay was used to compare the results provided by the EnVision++ system with those of the APAAP, CSA, LSAB, SABC, and ChemMate methods, when applied either manually or in a TechMate 500 immunostainer. RESULTS: With the vast majority of the antibodies, EnVision++ allowed two- to fivefold higher dilutions than the APAAP, LSAB, SABC, and ChemMate techniques, the staining intensity and percentage of expected positive cells being the same. With some critical antibodies (such as the anti-CD5), it turned out to be superior in that it achieved consistently reproducible results with differently fixed or overfixed samples. Only the CSA method, which includes tyramide based enhancement, allowed the same dilutions as the EnVision++ system, and in one instance (with the anti-cyclin D1 antibody) represented the gold standard. CONCLUSIONS: The EnVision++ is an easy to use system, which avoids the possibility of disturbing endogenous biotin and lowers the cost per test by increasing the dilutions of the primary antibodies. Being a two step procedure, it reduces both the assay time and the workload.

Psammocarcinoma with an aggressive course.

BACKGROUND: Psammocarcinoma is an unusual variant of serous cystadenocarcinoma characterized by heavy deposits of psammoma bodies. This disease has been suggested to be similar to carcinomas of low malignant potential in its indolent clinical course. We present this case report of an aggressive course of this disease to alert others that psammocarcinoma may not always follow a benign course. CASE: A 66-year-old woman underwent staging laparotomy for bilateral ovarian cystadenofibromata with rare foci of borderline serous tumors and several small bowel peritoneal surface nodules showing infiltrating psammocarcinoma. She was not recommended for adjuvant therapy because of the previously reported indolent course of this disease. Eighteen months later she represented with small bowel obstruction and underwent an exploratory laparotomy that demonstrated diffuse recurrence of the psammocarcinoma. CONCLUSION: Psammocarcinoma may have a more aggressive course than has been suggested. Patients with this disease should have optimal tumor debulking. There may be a role for adjuvant therapy in its treatment.

Is Hodgkin's disease a unique entity?

The theoretical bases of Hodgkin's disease (HD) have recently been revised in the light of new findings obtained by means of immunohistochemistry and molecular analysis. These findings have questioned the concept that HD is a unique entity and have made the borders between HD and non-Hodgkin's lymphomas unclear. The clinical relevance of nodular lymphocyte predominance HD (LP-HD), the distinction between T-cell rich B-cell lymphoma and diffuse LP-HD, and the relationships between HD and anaplastic large cell lymphoma are reviewed and discussed.

Retreatment with 2-CdA of progressed HCL patients.

Thirty seven hairy cell leukemia (HCL) patients, 35 males and 2 females with a median age of 53 years, were treated with a single course of 2-Chlorodeoxyadenosine (2-CdA) at a dose of 0.1 mg/kg daily for 7 days by continuous infusion. Twenty nine (78%) achieved a complete remission (CR) and 8 (22%) a partial remission (PR); four of the latter progressed after 6, 12, 18 and 24 months. All have been retreated with 2-CdA and 2 achieved a CR, 1 a PR and the last one is not yet evaluable. The overall median duration of response was 18 months, ranging from 4 to 30 months from the end of therapy. Circulating hairy cells and spleen enlargement, when present, disappeared within 2 weeks after completing treatment. A significant neutropenia was observed in almost all patients mainly in those who had less than 1,000/microliters neutrophils when treatment was started, together with a significant lymphocytopenia which lasted for more than 12 months. The hemoglobin and platelet levels were marginally affected. Fever was observed in 14 patients; in 8 of them it was short-lived (< or = 48 hours) and apparently not infection-related, while in the remaining 6 it was attributed to infection. Clinical tolerance was very good and none of the patients complained of nausea, vomiting or hair loss. In conclusion, our study confirms the efficacy of 2-CdA in HCL, including patients who progressed after treatment with 2-CdA.

Bone-marrow biopsy in hairy cell leukaemia (HCL) patients. Histological and immunohistological analysis of 46 cases treated with different therapies.

Serial bone-marrow biopsies were obtained from 46 hairy cell leukaemia (HCL) patients at different time intervals during the course of their disease. The patients were treated according to the following schemes: 14 received alpha-lymphoblastoid interferon (alpha-IFN), 11 2-Chlorodeoxyadenosine (2CdA), and 21 alpha-IFN first, followed by 2CdA. All the biopsies were studied by immunohistochemical means for the detection of minimal residual disease. The administration of 2CdA produced the highest reduction of both the tumor burden and HC index, with residual hairy cells (HCs) being undetectable at conventional light microscopy in most cases. In addition, 2CdA induced a higher degree of hypocellularity than alpha-IFN: the reduction in the amount of normal bone-marrow, however, was less pronounced in patients who had alpha-IFN before 2CdA. Of 9 patients who received both alpha-IFN and 2CdA and were followed for more than 2 years, 3 relapsed, while the remaining 6 continued to show rare HCs 2 years after 2CdA administration.

Anaplastic large cell lymphoma: update of findings.

The problem of anaplastic large cell lymphoma (ALCL) is extensively reviewed by depicting the clinical, pathological and biological characteristics of the four main varieties of ALCL: common, Hodgkin's like/Hodgkin-related, lympho-histiocytic, and giant-cell rich. Special emphasis is given to the differential diagnosis between ALCL Hodgkin like and Hodgkin's disease in the light of possible therapeutical differences.