A critical role for staphylococcal nitric oxide synthase in controlling flavohemoglobin toxicity.

Most coagulase-negative staphylococcal species, including the opportunistic pathogen Staphylococcus epidermidis, struggle to maintain redox homeostasis and grow under nitrosative stress. Under these conditions, growth can only resume once nitric oxide (NO) is detoxified by the flavohemoglobin Hmp. Paradoxically, S. epidermidis produces endogenous NO through its genetically encoded nitric oxide synthase (seNOS) and heavily relies on its activity for growth. In this study, we investigate the basis of the growth advantage attributed to seNOS activity. Our findings reveal that seNOS supports growth by countering Hmp toxicity. S. epidermidis relies on Hmp activity for its survival in the host under NO stress. However, in the absence of nitrosative stress, Hmp generates significant amounts of the harmful superoxide radical (O2•-) from its heme prosthetic group which impedes growth. To limit Hmp toxicity, nitrite (NO2-) derived from seNOS promotes CymR-CysK regulatory complex activity, which typically regulates cysteine metabolism, but we now demonstrate to also repress hmp transcription. These findings reveal a critical mechanism through which the bacterial NOS-Hmp axis drives staphylococcal fitness.

Reproducibility of Cytomorphological Diagnosis and Assessment of Risk of Malignancy of Thyroid Nodules Based on the Bethesda System for Reporting Thyroid Cytopathology: A Tertiary Cancer Center Perspective.

Introduction: The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) was introduced for unifying the terminology and morphologic criteria along with the corresponding risk of malignancy, leading to more consistent management approaches. The aim of this study was to study the utility and reproducibility of TBSRTC in reporting thyroid cytology in a referral cancer center. Methods: The fine-needle aspiration (FNA) of all thyroid nodules were included for a period of 5 years, from January 2016 to December 2021, in this cancer center. They were retrospectively reviewed and recategorized according to TBSRTC by two experienced pathologists. Cytohistopathological correlation was done for the cases which underwent surgical resection. Results: 522 fine-needle aspiration cytology (FNAC) of thyroid swellings were evaluated and categorized according to TBSRTC. There was agreement in the cytological diagnosis of 512 cases, of which 260 (50.78%) were benign lesions, 189 (36.91%) were malignant, 5 (0.97%) were unsatisfactory/nondiagnostic, 41 (8.01%) were follicular neoplasm/suspicious for neoplasm, 13 (2.53%) were suspicious for malignancy, and 4 (0.78%) cases were reported as atypia of undetermined significance. Two cytopathologists were in agreement in 512 cases (98%) of cases. Almost complete concordance was noted in the malignant (99%) and benign categories (98%). Disagreement was seen in 10 cases. Histological follow-up was available in 201 cases with an overall malignancy rate of 62.68% (126/201). Conclusion: TBSRTC proved to be a very simple and effective reporting system for thyroid FNAC, especially in the setting of a cancer center. This enables proper triaging of cases with thyroid masses into those who require surgical intervention and those who can avoid it, thereby preventing unnecessary morbidity.

A Plausible Proposition of CCL20-Related Mechanism in Fusobacterium nucleatum-Associated Oral Carcinogenesis.

OBJECTIVE: The objective of this prospective observational case-control study is to evaluate the prevalence of Fusobacterium nucleatum in the tissues of oral squamous cell carcinoma (OSCC). Reconnoitering the CCL20-related mechanism of carcinogenesis in Fusobacterium nucleatum-positive OSCC is another objective. METHODOLOGY: Tissues from 50 OSCC patients and 30 healthy oral tissues were collected. The prevalence of Fusobacterium nucleatum was evaluated in both tumour and healthy tissue by polymerase chain reaction. The immunohistochemistry of OSCC tissues was conducted to evaluate the difference in the expression of CCL20 between Fusobacterium nucleatum-positive and -negative OSCC tissues. RESULTS: Fusobacterium nucleatum was significantly (p < 0.001) prevalent in OSCC tissues (74%), compared to healthy tissues (26%). No association of Fusobacterium nucleatum or CCL20 immuno-expression with any clinical or histopathological features of OSCC was observed. While the intensity of CCL20 immuno-expression did not differ (p = 0.053), the CCL20-positive cell population was significantly different (p = 0.034) between Fusobacterium nucleatum-positive and -negative OSCC. CONCLUSION: Fusobacterium nucleatum is possibly prevalent in oral cancer tissues in the Indian population. By using immunohistochemistry, this is the first study to propose that the carcinogenesis in Fusobacterium nucleatum-positive OSCC may be CCL20-related. The findings enrich the knowledge of mechanisms involved in Fusobacterium nucleatum-mediated oral carcinogenesis.

Comparison of dosimetric data of bone marrow between standard IMRT and bone marrow sparing IMRT in carcinoma cervix.

BACKGROUND: The aim of the study was to assess the dosimetric comparison of bone marrow between standard IMRT(SD-IMRT) and bone marrow sparing IMRT (BMS-IMRT) among carcinoma cervix patients who underwent radical or adjuvant chemoradiation in a tertiary cancer center. MATERIALS AND METHODS: Forty eligible patients of histo-pathologically proven carcinoma cervix were enrolled in the study that was randomized on a 1:1 basis between SD-IMRT and BMS-IMRT from July 2018 to October 2019. The whole pelvis, bilateral femoral heads, and upper 1/3rd femur were contoured using the whole bone technique as a surrogate marker for the bone marrow. In both arms, V10, V20, and V40, bone marrow was noted along with mean, maximum, minimum dose, and total volume. DVH for the bone marrow in both arms was compared using the unpaired student t-test. RESULTS: We found no significant difference in the mean of various parameters in SD-IMRT arm vs. BMS IMRT arm - for the bone marrow: V10 (89 ± 4.3% vs. 86.7 ± 3.7%), V20 (73.2 ± 5.3% vs. 73.1 ± 4.5%), V40 (23.9 ± 5.4% vs. 26.6 ± 7.4%) and, similarly, for mean dose (28.1 ± 3.5% vs. 28.1 ± 1.8%), maximum dose (53.4 ± 0.58% vs. 53.2 ± 0.58%), minimum dose (0.33 ± 0.18% vs. 0.38 ± 0.38%), total volume (961 ± 110 cc vs. 901 ± 152 cc). CONCLUSION: This study shows no statistically significant difference in dosimetry between the two groups, which suggests that SD-IMRT spares the bone marrow adequately. Therefore, the need for BMS-IMRT using the present contouring technique does not give any added advantage over SD-IMRT. However, large sample size, other novel contouring technique, and multivariate analysis are needed to reach a definite conclusion.

Differential expression of cyclin E, p63, and Ki-67 in gestational trophoblastic disease and its role in diagnosis and management: A prospective case-control study.

BACKGROUND: Gestational trophoblastic disease (GTD) constitutes a spectrum of tumors and tumor-like conditions, characterized by proliferation of pregnancy-associated trophoblastic tissue of progressive malignant potential. It is very difficult to differentiate these complex groups of lesions basing on histomorphology alone. Immunohistochemistry (IHC) with cyclin E, P63, and Ki-67 has a definite role in the identification of different trophoblasts and entities of GTD and also in the determination of biological behavior. AIMS: The aim of this study is to find the differential expression of cyclin E, p63, and Ki-67 in normal placenta, hydropic abortus (HA), and various entities of GTD. DESIGN AND SETTINGS: A prospective case-control study conducted in a government medical college. METHODS: Total 96 cases, divided into Group A (48 histologically confirmed cases of GTD) and Group B (controls comprising 8 HA and 40 normal placentas of different trimesters), were studied. The histological samples were subjected to IHC using cyclin E, Ki-67, and p63. STATISTICAL ANALYSIS: Results were analyzed using SPSS statistical method. RESULTS: Among the three immunomarkers used, Cyclin E and Ki-67 show statistically significant difference (P < 0.05) when compared between GTD and control groups, but it was insignificant for p63 (P = 0.369). Strong staining intensity of cyclin E and Ki-67 is seen in complete moles, choriocarcinoma, and placental site trophoblastic tumor. CONCLUSION: This study was done to evaluate the role of cell cycle regulatory proteins such as cyclin E and p63 and proliferation marker Ki-67 in the detection of various trophoblasts and differential diagnosis of the lesions associated with them.

Clinicopathological study of malignant melanoma in a regional cancer center.

BACKGROUND: : Malignant melanoma is a tumor of melanocytic origin. Although uncommon in India as compared with the west, its prevalence is increasing. OBJECTIVES: To document the pattern of clinicopathological features of malignant melanoma cases attending in a regional cancer center in eastern India. MATERIAL AND METHODS: The present study was a retrospective study of 182 cases diagnosed histopathologically as malignant melanoma during 2011-2016. RESULTS: Out of the total cases, 170 (93.4%) were cutaneous and 12 (6.6%) were noncutaneous melanoma. The most common age group was sixth decade with a male predominance. Conventional melanotic melanomas were 176 (96.70%), and only 6 cases (3.30%) were amelanotic melanoma. Among noncutaneous melanomas, 6 were in anorectum, 2 in conjunctiva, and 1 case each in nasal cavity, palate, gingivo-buccal sulcus, and vagina. The acrallentigenous type was the most common variety, and the mixed epithelioid and spindle cell type was the most common histopathological pattern. Clark's level III was the most common level of invasion. CONCLUSION: The lower extremity is the most common site for melanoma, whereas extracutaneous melanomas are exceedingly rare and aggressive neoplasms. Melanoma can metastasize to regional lymph nodes, however, visceral metastasis to liver can also occur. In the absence of pigment in amelanotic melanoma, immunohistochemical markers such as HMB 45 can be used for definitive diagnosis.

Extrapulmonary Tuberculosis of Lymph Node Coexist with Diffuse Large B-cell Lymphoma: A Case Report.

Extrapulmonary tuberculosis (TB) coexistent with lymphomas in the same organ are rare. Here, we report a case of a 14-year-old male patient who had cauliflower-like ulcerated mass over cervical lymphadenopathy. He was diagnosed extrapulmonary TB. Unresponsiveness of anti tubercular treatment (anti-tubercular) treatment after 6 months, he was diagnosed as diffuse large B-cell lymphoma.

Serous Tubal Carcinogenesis: The Recent Concept of Origin of Ovarian, Primary Peritoneal and Fallopian Tube High-Grade Serous Carcinoma.

Background: Pelvic (non-uterine) high-grade serous carcinomas (PHGSC) including ovarian, tubal and primary peritoneal serous carcinomas have increased death: incidence ratio due to presentation at advanced stage, rapid progression, poor prognosis and high morbidity. Ambiguity regarding their pathogenesis and lack of a proper screening method is the cause of their late detection and high fatality rate. This study was undertaken to assess the fallopian tube for the presence of precursor lesions in pelvic serous carcinoma. Methods: This was a prospective case-control study carried out in a tertiary care center. Consecutive specimens of 55 cases of pelvic high-grade serous carcinoma and 41 controls inclusive of 21 low-grade serous carcinoma, 10 benign adnexal masses and 10 normal adnexa were included in the study. Both side fallopian tubes in each case were subjected to histopathological examination and p53, Ki67 immunohistochemistry. Results: There were 55 cases of PHGSC comprising of 50 cases of ovarian HGSC, two cases of primary peritoneal carcinoma (PPC) and three cases of tubal carcinoma. Serous tubal intraepithelial carcinoma (STIC) was detected in 14 cases (28%), p53 signature in 13 cases (26%) and tubal intraepithelial lesion in transition in 10 cases (20%) of ovarian HGSC. One case (50%) of PPC and one (33%) case of tubal carcinoma revealed the presence of STIC. None of the controls exhibited any precursor lesion except ovarian low-grade serous carcinoma where p53 was detected in 20% of cases. Conclusion: This revelation concludes that fallopian tubes are the sites of precursors of PHGSC to a large extent. In the absence of a proper screening method of HGSC, prophylactic bilateral salpingectomy at hysterectomy for benign diseases can achieve ultimate goal of reduction in incidence of PHGSC.

Poorly Differentiated Sertoli-Leydig Cell Tumour of Ovary with Heterologous Elements.

Sertoli-Leydig Cell Tumour (SLCT) is included under sex-cord stromal tumour of testis or ovary. Ovarian pathology is an extremely rare entity constituting less than 0.5% of all ovarian neoplasms. Majority of the cases present at younger age group, i.e., 2nd and 3rd decade of life. The clinical presentation depends on either mass effect or excess hormone production. Virillization symptoms are the most common presentation and depend upon the quantity of androgen production. Most of the patients have a unilateral mass without extraovarian spread and present at stage-I. Treatment and prognosis depends on the degree of the differentiation and the stage of the disease. Here, we report a case of SLCT of the ovary in a young female. The patient initially presented with pain abdomen due to mass effect and was treated with conservative surgery followed by adjuvant chemotherapy due to the presence of poorly differentiated pathology with heterologous elements.

Cervical strongyloidiasis in an immunocompetent patient: A clinical surprise.

A 32-year-old lady came for a routine gynecological check up. Her cervical cytologic smear was reported as low grade squamous intraepithelial lesion. As a part of basic routine investigation, cervical punch biopsy was done. Astonishingly it revealed multiple rhabditiform larvae of Strongyloides stercoralis. These were curved thick with pointed end and a short buccal cavity. She did not have any history of immunosuppression including steroid therapy and was otherwise normal. Extensive review of the literature on parasites encountered in cervix yielded few case reports on strongyloides in cytologic smears, but failed to reveal any report till date on S. stercoralis found in histopathology section. Our case is probably the first in the world and the first reported from India to the best of our knowledge. We describe this case of strongyloidiasis of cervix with review of the literature on various parasites encountered in the cervix because of its rarity and also to keep this parasitic infestation as a differential diagnosis of cervical lesions.

Role of fine needle aspiration cytology and cell block in diagnosis of scar endometriosis: A case report.

Presence of endometrial glands and stroma in places other than the uterus is called endometriosis. It can be pelvic or extra-pelvic. Abdominal scar endometriosis is an extra-pelvic endometriosis that can occur after surgery involving the uterus. Post-caesarean section, scar endometriosis is a rare event. The diagnosis is frequently made only after excision of disease tissue. We present a case of post-caesarean section abdominal scar endometriosis presenting as a tumor on the abdominal wall, which was diagnosed by fine needle aspiration cytology and confirmed by cell block preparation.

Development and evaluation of hexaplex PCR for rapid detection of methicillin, cadmium/zinc and antiseptic-resistant staphylococci, with simultaneous identification of PVL-positive and -negative Staphylococcus aureus and coagulase negative staphylococci.

We developed a multiplex PCR to detect the presence of methicillin- (mecA), cadmium/zinc-(czrC) and antiseptic-resistant (qacA/B) staphylococci and to identify Panton-Valentine leukocidin (PVL)-positive and -negative Staphylococcus aureus and coagulase-negative staphylococci (CoNS) from infected and healthy eyes. The assay was validated on 177 staphylococci comprising of 55 each of S. aureus and CoNS isolated from infected eyes and five S. aureus and 62 CoNS isolated from healthy eyes and nine direct ocular samples. Nine direct ocular samples for in situ testing consisted of corneal scrapings (4), conjunctiva swabs (2) and others (3). Multiplex PCR result was correlated with genotype data obtained with single PCR and dot-blot assay. The control strains that were positive in multiplex PCR for 16S rRNA, nuc, mecA, pvl, czrC and qacA/B genes were also positive in the dot-blot assay. The specificity of amplified genes obtained with reference strains was further confirmed by DNA sequencing. The single step-hexaplex PCR method can be used for rapid detection of mecA, nuc, pvl, czrC and qacA/B genes in staphylococci with simultaneous identification of PVL-positive and -negative S. aureus and CoNS from a variety of ocular samples.