The effect of short-term intensive chemotherapy on reactivation of tuberculosis.

BACKGROUND: Various malignancies and cytotoxic chemotherapy have been proposed to increase the risk of reactivation of tuberculosis. Available literature to support this observation is still conflicting. There is scarcity of data from countries with rampant tubercular infection, such as India, in this regard. DESIGN AND METHODS: In the present retrospective analysis, patients with high-grade non-Hodgkin's lymphoma with past history of tuberculosis and have had adequate antitubercular therapy were identified from a Lymphoma Group study. These patients were followed up during cytotoxic chemotherapy and later to assess the risk of reactivation. RESULTS: A cohort of eight patients with past history of tuberculosis was selected from 141 patients of high-grade non-Hodgkin's lymphoma. The median age was 33.5 years (range, 24-53 years). Median duration between completion of antitubercular treatment and diagnosis of lymphoma was 5 years (range, 1.5-10 years). All patients received cyclical cytotoxic chemotherapy. The median duration of follow up after completion of chemotherapy was 5 years (range, 10 months to 5 years). None of these patients developed reactivation of tuberculosis. CONCLUSION: Cyclical chemotherapy for non-Hodgkin's lymphoma does not lead to reactivation of tuberculosis.     

Malignant progression of B16 melanoma cells induced in vitro by growth factors produced by highly malignant cells

Four mouse B16 melanoma subclones (G3.15, G3.5, G3.12 and G3.26) exhibit progressively greater growth capacity in vitro and in vivo. Previously, non-metastatic G3.15 cells were sequentially converted, in monolayer cultures, to the moderately-metastatic G3.5 cells, and then to a highly-metastatic G3.5^* phenotype. Both conversions were induced by hypoxia followed by confluence, and also occurred in tumors. G3.5^* cells were comparable with, yet distinguishable from, G3.12 cells in being growth-autonomous in culture. In this study, the presumption that rapidly-growing G3.26 cells represented the ultimate progression step in this clonal system was examined. Both G3.12 and G3.5^* cells converted in vitro to the G3.26 phenotype during growth in serum-free medium conditioned by G3.26 cell growth. By selective filtration of conditioned medium and characterization of the stability of growth- and conversion-promoting activities, three distinct activities were found to promote a two-step G3.12 to G3.26 phenotype conversion: (1) a < 10 kDa filtrate stimulated slight attachment and proliferation of G3.12 cells, effects that were reversible, partly attributable to accumulated lactate, and fully mimicked by medium acidification to pH 6.5; (2) medium acidification, together with a heat- and acid-stable but partially trypsin-sensitive > 10 kDa activity, induced G3.12 G3.5^* conversion that resulted in acquisition of growth autonomy; and (3) a heat-, acid- and trypsin-sensitive > l0 kDa activity induced G3.5^* G3.26 conversion, characterized by anchorage-independent growth in soft agar, and potent lung colonization following intravenous injection. Phenotype analysis of G3.12 tumors and lung metastases revealed that G3.5^*-like cells were regularly present in tumors and metastases, whereas G3.26-like cells occurred almost exclusively in large lung metastases. While G3.12 cells might convert to G3.5^* cells in order to disseminate, G3.26 cells are apparently not involved in metastatic spread but probably account for the rapid growth of established metastases.     

Cytopathology of uncommon malignant renal neoplasms in the pediatric age group

Malignant renal neoplasms are common solid tumors in pediatric oncology practice. These include the common Wilms' tumor/nephroblastoma and the uncommon neoplasms such as clear-cell sarcoma of the kidney (CCSK), rhabdoid tumor, renal-cell carcinoma, and others. The aim of this study was to describe in detail the cytopathological features of the histopathologically proven uncommon pediatric renal tumors. Aspirates from Wilms' tumor, which are mesenchyme predominant, show clusters of spindle cells associated with the matrix material. Evidence of rhabdomyoblastic differentiation may be present. CCSK, classic subtype, is characterized by round to oval cells arranged perivascularly and also in sheets and clusters intimately associated with a metachromatic matrix mucopolysaccharide material better appreciated in May-Grunwald-Giemsa (MGG)-stained smears. The cells also have more abundant cytoplasm and may show nuclear grooves. Spindle-cell pattern of CCSK is difficult to diagnose on aspiration cytology. Renal-cell carcinoma of childhood shows similar cytological features as its adult counterpart. Rhabdoid tumor of the kidney is characterized by a monomorphic population of cells with abundant cytoplasm, eccentric nuclei with prominent nucleoli. Intrarenal yolk sac tumor is a rare neoplasm and shows severely pleomorphic cells on aspiration.Awareness of these entities is important for the practicing cytopathologist. Further, non-Wilms' renal malignant neoplasms must be distinguished from the common Wilms' tumor so that appropriate chemotherapy protocols may be instituted in cases where the tumor is in an advanced stage of malignancy.     

Kinetics of the nitrogen dioxide initiated polymerization of acrylic acid

Acrylic acid (AA) was polymerized with NO₂ in tetrahydrofuran (THF) and in 1,4-dioxane. The effects of monomer and initiator concentration and of temperature on polymer conversion, initial rate of polymerization, and molecular weight were studied. The overall activation energy of polymerization was found to be 16,3 kcal mol^?1 (68,23 kJ · mol^?1) and 15,54 kcal · mol^?1 (65,05 kJ · mol^?1) in THF and in 1,4-dioxane, respectively. High molecular weight polymers (M ca. 10⁵) were obtained. The polymerization appears to be initiated by free radicals.     

Recurrent diffuse lipomatosis of the neck--a case report

Diffuse lipomatosis is a rare disorder of adipose tissue occurring in young people . It has a predilection for trunk and proximal extremities where it presents as poorly circumscribed overgrowth of fatty tissue. Definite diagnosis is established by histological examination of tumor. Though it attains extensive size and has a high tendency to recur, the clinical course is benign.     

Association of obesity with illness severity in hospitalized patients with COVID-19: A retrospective cohort study

BackgroundAlthough recent studies have shown an association between obesity and adverse coronavirus disease 2019 (COVID-19) patient outcomes, there is a paucity in large studies focusing on hospitalized patients. We aimed to analyze outcomes associated with obesity in a large cohort of hospitalized COVID-19 patients.MethodsWe performed a retrospective study at a tertiary care health system of adult patients with COVID-19 who were admitted between March 1 and April 30, 2020. Patients were stratified by body mass index (BMI) into obese (BMI ≥ 30 kg/m 2) and non-obese (BMI < 30 kg/m 2) cohorts. Primary outcomes were mortality, intensive care unit (ICU) admission, intubation, and 30-day readmission.ResultsA total of 1983 patients were included of whom 1031 (51.9%) had obesity and 952 (48.9%) did not have obesity. Patients with obesity were younger (P < 0.001), more likely to be female (P < 0.001) and African American (P < 0.001) compared to patients without obesity. Multivariable logistic models adjusting for differences in age, sex, race, medical comorbidities, and treatment modalities revealed no difference in 60-day mortality and 30-day readmission between obese and non-obese groups. In these models, patients with obesity had increased odds of ICU admission (adjusted OR, 1.37; 95% CI, 1.07?1.76; P = 0.012) and intubation (adjusted OR, 1.37; 95% CI, 1.04?1.80; P = 0.026).ConclusionsObesity in patients with COVID-19 is independently associated with increased risk for ICU admission and intubation. Recognizing that obesity impacts morbidity in this manner is crucial for appropriate management of COVID-19 patients.