Human papillomavirus (HPV)-related oropharyngeal nonkeratinizing squamous cell carcinoma: characterization of a distinct phenotype.

We have recently shown that HPV-positive tonsillar carcinoma in young patients exhibits nonkeratinizing basaloid morphology and a characteristic immunophenotype. The purpose of this study was to review a large number of cases of oropharyngeal carcinomas, in all age groups, and to identify tumors with nonkeratinizing morphology. Using polymerase chain reaction (PCR) the prevalence and type of HPV DNA was determined in representative cases and in a control group of conventional keratinizing squamous cell carcinomas. The tumors were further characterized with a panel of immunohistochemical stains. A total of 235 carcinomas were reviewed; 141 of the tonsils and 94 in the base of tongue. Ninety (36%) of the tonsillar and 30 (32%) of the base of tongue carcinomas were nonkeratinizing (NKCa) with basal cell features; the rest were classical keratinizing squamous cell carcinomas (KSCC). HPV DNA, particularly type 16, was identified in 10 (100%) of 10 of NKCA and in only 2 (20%) of 10 of KSCC (P = .0014). NKCas were strongly reactive to p16 antibodies while KSCC showed weak and focal reactivity. Higher Ki67 and lower p53 staining scores were observed in NKCa as compared to KSCC. It is concluded that NKCa of the tonsils and base of tongue is a distinct subtype of squamous cell carcinoma of the head and neck with high prevalence of HPV DNA and a characteristic immunophenotype.     

Subtype B and subtype C HIV type 1 recombinants in the northeastern state of Manipur, India

The predominant HIV-1 strain circulating in India is subtype C. However, subtype A and B strains of HIV-1 have also been reported in India. In 1999, the first A/C recombinant strain was reported from Pune in India. Intravenous drug users (IVDUs) from the northeastern region of India have a high HIV-1 seroprevalence. Studies carried out in intravenous drug users in the northeastern region of India have shown that HIV-1 subtype C is the predominant strain infecting IVDUs. Fourteen blood samples were collected from HIV-1-infected individuals from the northeastern region of India and screened by env and gag heteroduplex mobility assays (HMA). Where the env and gag HMA results from a sample yielded different subtypes, sequencing of env and gag PCR products was carried out to confirm the presence of HIV-1 recombinants. Of the 14 samples subtyped, nine samples belonged HIV-1 subtype C (gag C/env C), one to HIV-1 subtype B (gag B/env B), and the remaining were B/C recombinants (gag C/env B). This is the first report of HIV-1 B/C recombinants from India.     

Tooth in a cyst — Is it always a dentigerous cyst?

We present the case report of an 18-year-old female patient who presented with unilateral nasal obstruction. Computed tomography scanning revealed an unerupted molar in the posterior wall of the right maxillary sinus with a cystic swelling in the sinus. The preoperative diagnosis was a dentigerous cyst. The patient underwent endoscopic removal of the cyst and tooth. The operative findings and histopathology showed that it was an odontogenic keratocyst. This paper stresses the importance of diagnosing this condition and that a tooth in a cyst is not always dentigerous.     

Anticoagulant-resistant thrombophilia in a patient with polycythemia vera: a case report

Mechanical valve thrombosis is a rare condition in an adequately anticoagulated patient in the absence of underlying thrombophilia. We report a case of a 76-year-old male with mechanical prosthetic mitral valve thrombosis as the presenting feature of polycythemia vera. The patient was treated with thrombolysis at the time of acute presentation and subsequently maintained on low molecular weight heparin, low-dose aspirin, phlebotomy and hydroxyurea. Hemoglobin, leucocytosis and platelet count were controlled for almost 4 years after which the patient suffered a second, fatal episode in the setting of therapeutic anti-Xa level. This case report highlights the thrombotic risks associated with polycythemia vera. The proposed mechanisms of hypercoagulability in polycythemia vera are reviewed. To the best of our knowledge, mechanical valve thromboses as the presenting feature of polycythemia vera has not been reported previously.     

Susceptibility to gut leakiness: a possible mechanism for endotoxaemia in non‐alcoholic steatohepatitis

Introduction: One of the proposed second hit mechanisms in the pathophysiology of non‐alcoholic steatohepatitis (NASH) is hepatic oxidative stress triggered by elevated levels of endotoxin. We investigated one possible mechanism for the endotoxaemia – disruption of intestinal barrier integrity. Methods: We enrolled 16 subjects with fatty liver (10 NASH; 6 steatosis) and 12 healthy subjects. Steatosis and NASH were diagnosed by liver biopsy using the Brunt criteria. Gastrointestinal permeability was measured using urinary excretion of 5‐h lactulose/mannitol (L/M) ratio and 24‐h sucralose. Permeability testing was repeated after aspirin challenge. Results: Groups had similar baseline urinary 0–5 h L/M ratio (small bowel permeability) and 0–24 h sucralose (whole‐gut permeability). Aspirin increased 0–5 h urinary L/M in most subjects. In contrast, aspirin significantly increased whole‐gut permeability only in NASH subjects. In fact, the major increase in the urinary sucralose occurred in the 6–24 h samples, which points towards the colon as the major site responsible for aspirin‐induced leakiness in NASH patients. Serum endotoxin levels were significantly higher in NASH subjects. Discussion: Our findings suggest that aspirin acts on the colon to unmask a susceptibility to gut leakiness in patients with NASH. This effect may be the underlying mechanism for increased serum endotoxin, which is the second hit (after altered lipid metabolism) that is required to initiate a necroinflammatory cascade in hepatocytes which are already primed with obesity‐induced abnormal lipid homoeostasis.