DETERMINATION OF VIRAL TROPISM BY GENOTYPING AND PHENOTYPING ASSAYS IN BRAZILIAN HIV-1-INFECTED PATIENTS

The clinical application of CCR5 antagonists involves first determining the coreceptor usage by the infecting viral strain. Bioinformatics programs that predict coreceptor usage could provide an alternative method to screen candidates for treatment with CCR5 antagonists, particularly in countries with limited financial resources. Thus, the present study aims to identify the best approach using bioinformatics tools for determining HIV-1 coreceptor usage in clinical practice. Proviral DNA sequences and Trofile results from 99 HIV-1-infected subjects under clinical monitoring were analyzed in this study. Based on the Trofile results, the viral variants present were 81.1% R5, 21.4% R5X4 and 1.8% X4. Determination of tropism using a Geno2pheno_[coreceptor] analysis with a false positive rate of 10% gave the most suitable performance in this sampling: the R5 and X4 strains were found at frequencies of 78.5% and 28.4%, respectively, and there was 78.6% concordance between the phenotypic and genotypic results. Further studies are needed to clarify how genetic diversity amongst virus strains affects bioinformatics-driven approaches for determining tropism. Although this strategy could be useful for screening patients in developing countries, some limitations remain that restrict the wider application of coreceptor usage tests in clinical practice.     

Serum thyroid hormone levels in healthy children from birth to adulthood and in short children born small for gestational age

Context: Age-appropriate reference ranges for thyroid hormones are required for detecting pediatric thyroid dysfunction. Data on thyroid hormones and peripheral thyroid metabolism in short children born small for gestational age (SGA) before and during GH treatment are lacking. Objectives: Our objectives were to obtain pediatric thyroid hormone reference ranges; to investigate thyroid hormones in short SGA children before puberty, during puberty, and during postponement of puberty by GnRH analog; and to evaluate thyroid hormones during GH treatment. Patients and Design: In 512 healthy children (225 females; 0-18 yr), free T(4) (FT(4)), TSH, total T(4), T(3), rT(3), and T(4)-binding globulin were determined. Reference ranges were calculated using the linearity, median, and skewness method. In 125 short SGA children (62 females; mean age 11.3 yr), thyroid hormones were analyzed before and after 2 yr of GH treatment and additional GnRH analog. Results: Thyroid references showed wide ranges postnatally and age-specific patterns thereafter, similar in boys and girls. Untreated short SGA children had similar FT(4) and T(4) levels as the reference population but significantly higher T(3), rT(3), and T(4)-binding globulin levels. During puberty and during GH treatment, FT(4) and rT(3) significantly decreased, whereas T(3) significantly increased. Conclusion: Age-specific thyroid reference ranges are presented. Puberty and GH treatment both induce changes in peripheral thyroid metabolism, resulting in more biologically active T(3) at the expense of less inactive rT(3), possibly mediated by IGF-I. GH treatment induces altered peripheral thyroid metabolism but does not result in thyroid dysfunction.     

Bruton tyrosine kinase inhibition is a novel therapeutic strategy targeting tumor in the bone marrow microenvironment in multiple myeloma

Bruton tyrosine kinase (Btk) has a well-defined role in B-cell development, whereas its expression in osteoclasts (OCs) further suggests a role in osteoclastogenesis. Here we investigated effects of PCI-32765, an oral and selective Btk inhibitor, on osteoclastogenesis as well as on multiple myeloma (MM) growth within the BM microenvironment. PCI-32765 blocked RANKL/M-CSF-induced phosphorylation of Btk and downstream PLC-γ2 in OCs, resulting in diminished TRAP5b (ED(50) = 17nM) and bone resorption activity. PCI-32765 also inhibited secretion of multiple cytokines and chemokines from OC and BM stromal cell cultures from both normal donors (ED(50) = 0.5nM) and MM patients. It decreased SDF-1-induced migration of MM cells, and down-regulated MIP1-α/CCL3 in MM cells. It also blocked MM cell growth and survival triggered by IL-6 or coculture with BM stromal cells or OCs in vitro. Importantly, PCI-32765 treatment significantly inhibits in vivo MM cell growth (P < .03) and MM cell-induced osteolysis of implanted human bone chips in SCID mice. Moreover, PCI-32765 prevents in vitro colony formation by stem-like cells from MM patients. Together, these results delineate functional sequelae of Btk activation mediating osteolysis and growth of MM cells, supporting evaluation of PCI-32765 as a novel therapeutic in MM.     

In situ mantle cell lymphoma: clinical implications of an incidental finding with indolent clinical behavior

Background

Cyclin D1-positive B cells are occasionally found in the mantle zones of reactive lymphoid follicles, a condition that has been called “in situ mantle cell lymphoma”. The clinical significance of this lesion remains uncertain.

Design and Methods

The clinical and pathological characteristics, including SOX11 expression, of 23 cases initially diagnosed as in situ mantle cell lymphoma were studied.

Results

Seventeen of the 23 cases fulfilled the criteria for in situ mantle cell lymphoma. In most cases, the lesions were incidental findings in reactive lymph nodes. The t(11;14) was detected in all eight cases examined. SOX11 was positive in seven of 16 cases (44%). Five cases were associated with other small B-cell lymphomas. In two cases, both SOX11-positive, the in situ mantle cell lymphoma lesions were discovered after the diagnosis of overt lymphoma; one 4 years earlier, and one 3 years later. Twelve of the remaining 15 patients had a follow-up of at least 1 year (median 2 years; range, 1–19.5), of whom 11 showed no evidence of progression, including seven who were not treated. Only one of 12 patients with an in situ mantle cell lymphoma lesion and no diagnosis of mantle cell lymphoma at the time developed an overt lymphoma, 4 years later; this case was also SOX11-positive. The six remaining cases were diagnosed as mantle cell lymphoma with a mantle zone pattern. Five were SOX11-positive and four of them were associated with lymphoma without a mantle zone pattern.

Conclusions

In situ mantle cell lymphoma lesions are usually an incidental finding with a very indolent behavior. These cases must be distinguished from mantle cell lymphoma with a mantle zone pattern and overt mantle cell lymphoma because they may not require therapeutic intervention.     

Interposición de intestino delgado entre el colon y el recto como forma de lograr una anastomosis pélvica sin tensión

Purpose

There are some circumstances in which the descending colon does not reach the pelvis to complete a colorectal anastomosis without tension. Re-establishing intestinal continuity by interposing small bowel as a bridge between the colon and the rectum could be an acceptable surgical alternative.

Methods

We describe the interposition of one or two segments of small bowel as a way of restoring continuity of the colon and rectum in three patients in whom it was not possible to perform a colorectal anastomosis without tension due to ischaemic colon, synchronous cancer or difficulty in accessing the supramesocolic space, respectively.

Results

Intestinal continuity was re-established in all patients with no significant morbidity and good intestinal function.

Conclusion

The interposition of small bowel segments between the colon and the rectum should be considered a valid surgical option when it is not possible to achieve a well-perfused, tension-free pelvic colorectal anastomosis.     

Drug resistance and coreceptor usage in HIV type 1 subtype C-infected children initiating or failing highly active antiretroviral therapy in South Africa

HIV-1 drug resistance monitoring in resource-poor settings is crucial due to limited drug alternatives. Recent reports of the increased prevalence of CXCR4 usage in subtype C infections may have implications for CCR5 antagonists in therapy. We investigated the prevalence of drug resistance mutations and CXCR4 coreceptor utilization of viruses from HIV-1 subtype C-infected children. Fifty-one children with virological failure during highly active antiretroviral therapy (HAART) and 43 HAART-naive children were recruited. Drug resistance genotyping and coreceptor utilization assessment by phenotypic and genotypic methods were performed. At least one significant drug resistance mutation was present in 85.4% of HAART-failing children. Thymidine analogue mutations (TAMs) were detected in 58.5% of HAART-failing children and 39.0% had ≥3 TAMs. CXCR4 (X4) or dual (R5X4)/mixed (R5, X4) (D/M)-tropic viruses were found in 54.3% of HAART-failing and 9.4% of HAART-naive children (p<0.0001); however, the HAART-failing children were significantly older (p<0.0001). In multivariate logistic regression, significant predictors of CXCR4 usage included antiretroviral treatment, older age, and lower percent CD4(+) T cell counts. The majority of genotypic prediction tools had low sensitivity (≤65.0%) and high specificity (≥87.5%) for predicting CXCR4 usage. Extensive drug resistance, including the high percentage of TAMs found, may compromise future drug choices for children, highlighting the need for improved treatment monitoring and adherence counseling. Additionally, the increased prevalence of X4/D/M viruses in HAART-failing children suggests limited use of CCR5 antagonists in salvage therapy. Enhanced genotypic prediction tools are needed as current tools are not sensitive enough for predicting CXCR4 usage.     

Surgeon Migration Between Developing Countries and the United States: Train, Retain, and Gain from Brain Drain

Background

The critical shortage of surgeons in many low- and middle-income countries (LMICs) prevents adequate responses to surgical needs, but the factors that affect surgeon migration have remained incompletely understood. The goal of this study was to examine the importance of personal, professional, and infrastructural factors on surgeon migration from LMICs to the United States. We hypothesized that the main drivers of surgeon migration can be addressed by providing adequate domestic surgical infrastructure, surgical training programs, and viable surgical career paths.

Methods

We conducted an internet-based nationwide survey of surgeons living in the US who originated from LMICs.

Results

66 surgeons completed the survey. The most influential factors for primary migration were related to professional reasons (p ≤ 0.001). Nonprofessional factors, such as concern for remuneration, family, and security were significantly less important for the initial migration decisions, but adopted a more substantial role in deciding whether or not to return after training in the United States. Migration to the United States was initially considered temporary (44 %), and a majority of the surveyed surgeons have returned to their source countries in some capacity (56 %), often on multiple occasions (80 %), to contribute to clinical work, research, and education.

Conclusions

This study suggests that surgically oriented medical graduates from LMICs migrate primarily for professional reasons. Initiatives to improve specialist education and surgical infrastructure in LMICs have the potential to promote retention of the surgical workforce. There may be formal ways for LMICs to gain from the international pool of relocated surgeons.