Soluble-protein and antigenic heterogeneity in axenic Blastocystis hominis isolates: pathogenic implications

The protein profile and the antigenic cross-reactivity of 18 axenic isolates of Blastocystis hominis obtained from symptomatic patients with chronic diarrhea (14 isolates) showing no evidence of parasitic etiology and from patients with acute diarrhea attributable in 2 cases to Salmonella spp. were analyzed. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of soluble proteins showed the existence of a common profile composed of 31 bands, with molecular weights ranging between 24 and >200 kDa, and minor differences in the proteins of 149, 118, 106, 50, 48, 47, and 30 kDa. These differences allowed us to classify the strains into three related patterns (I–III). In an indirect immunofluorescence assay, all strains were serologically identical, but two related antigenic groups (1 and 2) were found in double-immunodiffusion and Western-blot studies. The isolates of protein patterns I and II belonging to antigenic group 1 were isolated from patients with chronic diarrhea, whereas the four isolates from patients with acute diarrhea were clustered in protein pattern III and in antigenic group 2. These results confirm the protein and antigenic heterogeneity of B. hominis and the existence of demes with different pathogenic roles. Received: 10 April 1998 / Accepted: 6 August 1998     

Absence of chromosomal instability in spermatozoa of men affected by testicular cancer.

Testicular germ cell cancer affects mainly young men. It is the most frequent type of cancer in 20-35 year old men. Since cancer treatment using antineoplasic drugs and ionizing radiation has a negative effect on the function of the gonads, testicular cancer patients are offered the opportunity to cryopreserve their semen samples before the beginning of therapy. For this reason it would be of interest to know whether there is chromosome instability in their spermatozoa prior to any treatment. Using the interspecific human-hamster fertilization system, we have analysed a total of 340 chromosome complements from spermatozoa of control donors and 320 chromosome complements from testicular cancer patients. There were no significant differences in the frequencies of chromosomal aberrations between controls and cancer patients (9.7 and 10.3% respectively; P = 0.4921). Our results indicate that spermatozoa from untreated testicular cancer patients do not show an increased chromosomal instability as compared to control donors.     

Persistence of Neutralizing Antibodies to SARS-CoV-2 in First Wave Infected Individuals at Ten Months Post-Infection: The UnIRSA Cohort Study

Longitudinal mapping of antibody-based SARS-CoV-2 immunity is critical for public health control of the pandemic and vaccine development. We performed a longitudinal analysis of the antibody-based immune response in a cohort of 100 COVID-19 individuals who were infected during the first wave of infection in northern Italy. The SARS-CoV-2 humoral response was tested using the COVID-SeroIndex, Kantaro Quantitative SARS-CoV-2 IgG Antibody RUO Kit (R&D Systems, Bio-Techne, Minneapolis, USA) and pseudotype-based neutralizing antibody assay. Using sequential serum samples collected from 100 COVID-19 recovered individuals from northern Italy—mostly with mild disease—at 2 and 10 months after their first positive PCR test, we show that 93% of them seroconverted at 2 months, with a geometric mean (GeoMean) half-maximal neutralization titer (NT50) of 387.9. Among the 35 unvaccinated subjects retested at 10 months, 7 resulted seronegative, with an 80% drop in seropositivity, while 28 showed decreased anti-receptor binding domain (RBD) and anti-spike (S) IgG titers, with a GeoMean NT50 neutralization titer dropping to 163.5. As an NT50 > 100 is known to confer protection from SARS-CoV-2 re-infection, our data show that the neutralizing activity elicited by the natural infection has lasted for at least 10 months in a large fraction of subjects.     

Patterns of relapse in stage I–II uterine papillary serous carcinoma treated with adjuvant intravaginal radiation (IVRT) with or without chemotherapy

Objective

To evaluate patterns of relapse in early stage uterine papillary carcinoma (UPSC) patients receiving adjuvant intravaginal radiotherapy (IVRT) with or without chemotherapy.

Methods

From 1/1996 to 12/2010, 77 women with stage I–II UPSC underwent surgery followed by IVRT (median 21 Gy). Stage IA patients without residual disease at surgery were excluded. IVRT and chemotherapy (carboplatin/taxane) was given to 61 (79%) patients and IVRT alone to 16 (21%). The median follow-up was 62 months for surviving patients.

Results

Of the 77 patients, 11 (14%) relapsed as follows: vaginal 2 (3%), pelvic 5 (6%), para-aortic 5 (6%), peritoneal 6 (8%), and other distant sites 8 (10%). Of the 5 pelvic relapses, 2 were isolated and were salvaged. In those treated without chemotherapy, only 1/16 developed recurrence (mediastinal). The 5-year vaginal, pelvic, para-aortic, peritoneal, and distant recurrence rates were 2.7% (C.I. 0–6.2%), 5.8% (C.I. 0.6–11.0%), 5.4% (C.I. 0.6–10.1%), 5.3% (C.I. 0.5–10.1%) and 6.6% (C.I. 1.4–11.8%), respectively. The 5-year disease-free survival (DFS), and overall survival (OS) were 88% (C.I. 81–95%), and 91% (C.I. 84–97%), respectively. The only predictor of worse 5-year pelvic control was stage (96.2% stage IA vs 87.7% for stage IB-II, p = 0.043).

Conclusions

In stage I–II UPSC patients who predominantly receive adjuvant chemotherapy, IVRT as the sole form of adjuvant RT provides excellent locoregional control. The risk of isolated pelvic recurrence is too low to warrant routine use of external pelvic RT.     

Perivascular structures in corrosion casts of the human central nervous system: A confocal laser and scanning electron microscope study

Scanning electron microscopy (SEM) of microvascular corrosion casts revealed perivascular structures that resembled smooth muscle and pericyte cells. Although these structures have been studied in widely different experimental contexts, their origin, function, and distribution pattern in different tissues are not understood. Microvascular corrosion casts from 15 fresh human brains and 20 lumbar spinal cords were studied by SEM. In five cerebral hemispheres a fluorescent resin was injected in order to study the vascular bed by confocal laser scanning microscopy (CLSM). Microvascular casts showed two perivascular structures on their surfaces: plastic strips, which formed a muff around arteriolar vessels, and pericyte-like structures that were present around the capillary network. Their morphological characteristics and distribution were similar to those of smooth muscle cells and pericytes, respectively. The SEM study showed that these structures were not tightly joined to the cast surface, but were connected to the vascular cast by narrow plastic connections. The CLSM showed that the resin invaded the subendothelial space, thus giving rise to these structures. Perivascular structures associated with arteriolar and capillary vessels appear to represent smooth muscle cells and pericytes. They are formed by the passage of the resin to the subendothelial space, probably through weak endothelial cell junctions. The effusion of resin into the subendothelial space may represent evidence for the structural basis of myocyte and pericyte cell control. Chemical communication by substances released locally or transported to these cells through these junctions may regulate their functions, allowing them to regulate blood flow. Anat. Rec. 252:176–184, 1998. © 1998 Wiley-Liss, Inc.