Hepatitis B assessment without hepatitis B virus DNA quantification: a prospective cohort study in Uganda

BACKGROUND: Chronic hepatitis B infection affects 240 million people, with the highest prevalence in Africa and Asia, and results in 700 000 deaths annually. Access to diagnostics, particularly for hepatitis B virus viral load quantification (HBV DNA), is a major barrier to treatment. We aimed to test World Health Organization guidelines for hepatitis B management in resource-limited settings. METHODS: We compared treatment allocation with and without the use of HBV DNA in a cohort in Uganda. Hepatitis B surface antigen test-positive, human immunodeficiency virus-negative, treatment-naïve adults were recruited prospectively. Following liver ultrasound and routine haematological and biochemical tests, preliminary allocations into treatment and observation groups were made. HBV DNA was performed for each participant and final treatment decisions were made and compared with preliminary allocations. RESULTS: Full assessment was completed for 100 participants; treatment was indicated in 20. Assessment without HBV DNA identified patients for treatment with a positive predictive value of 88.2% and a negative predictive value of 94% compared with assessment using HBV DNA. CONCLSUIONS: Where HBV DNA is unavailable, patients with hepatitis B can be assessed by liver ultrasound and routine laboratory tests. These findings will enable physicians in resource-limited settings to initiate treatment more readily and inform policy with regards to viral hepatitis elimination

Evolved CYP102A1 (P450BM3) variants oxidise a range of non-natural substrates and offer new selectivity options

The evolution of CYP102A1 variants with enhanced activity and altered specificity characteristics.Christopher J. C. Whitehouse, Stephen G. Bell, Henry G. Tufton, Richard J. P. Kenny, Lydia C. I. Ogilvie and Luet-Lok Won

Structure, electronic properties and catalytic behaviour of an activity-enhancing CYP102A1 (P450BM3) variant

The substrate-free crystal structure of a five-mutation directed evolution variant of CYP102A1 (P450(sub)BM3) with generic activity-enhancing properties (“KT2”) has been determined to 1.9-Å resolution. There is a close resemblance to substrate-bound structures of the wild-type enzyme (WT). The disruption of two salt bridges that link the G- and I-helices in WT causes conformational changes that break several hydrogen bonds and reduce the angle of the kink in the I-helix where dioxygen activation is thought to take place. The side-chain of a key active site residue, Phe87, is rotated in one molecule of the asymmetric unit, and the side-chains of Phe158 and Phe261 cascade into the orientations found in fatty-acid-bound forms of the enzyme. The iron is out of the porphyrin plane, towards the proximal cysteine. Unusually, the axial water ligand to the haem iron is not hydrogen-bonded to Ala264. The first electron transfer from the reductase domain to the haem domain of substrate-free KT2 is almost as fast as in palmitate-bound WT even though the reduction potential of the haem domain is only slightly more oxidising than that of substrate-free WT. However, NADPH is turned over slowly in the absence of substrate, so the catalytic cycle is gated by a step subsequent to the first electron transfer—a contrast to WT. Propylbenzene binding slightly raises the first electron transfer rate in WT but not in KT2. It is proposed that the generic rate accelerating properties of KT2 arise from the substrate-free form being in a catalytically ready conformation, such that substrate-induced changes to the structure play a less significant role in promoting the first electron transfer than in WT.Christopher J. C. Whitehouse, Wen Yang, Jake A. Yorke, Henry G. Tufton, Lydia C. I. Ogilvie, Stephen G. Bell, Weihong Zhou, Mark Bartlam, Zihe Raob, and Luet-Lok Won

SDHC phaeochromocytoma and paraganglioma: A UK‐wide case series

Objective Phaeochromocytomas and paragangliomas (PPGL) are rare, but strongly heritable tumours. Variants in succinate dehydrogenase (SDH) subunits are identified in approximately 25% of cases. However, clinical and genetic information of patients with SDHC variants are underreported. Design This retrospective case series collated data from 18 UK Genetics and Endocrinology departments. Patients Both asymptomatic and disease-affected patients with confirmed SDHC germline variants are included. Measurements Clinical data including tumour type and location, surveillance outcomes and interventions, SDHC genetic variant assessment, interpretation, and tumour risk calculation. Results We report 91 SDHC cases, 46 probands and 45 non-probands. Fifty-one cases were disease-affected. Median age at genetic diagnosis was 43 years (range: 11–79). Twenty-four SDHC germline variants were identified including six novel variants. Head and neck paraganglioma (HNPGL, n = 30, 65.2%), extra-adrenal paraganglioma (EAPGL, n = 13, 28.2%) and phaeochromocytomas (PCC) (n = 3, 6.5%) were present. One case had multiple PPGLs. Malignant disease was reported in 19.6% (9/46). Eight cases had non-PPGL SDHC-associated tumours, six gastrointestinal stromal tumours (GIST) and two renal cell cancers (RCC). Cumulative tumour risk (95% CI) at age 60 years was 0.94 (CI: 0.79–0.99) in probands, and 0.16 (CI: 0–0.31) in non-probands, respectively. Conclusions This study describes the largest cohort of 91 SDHC patients worldwide. We confirm disease-affected SDHC variant cases develop isolated HNPGL disease in nearly 2/3 of patients, EAPGL and PCC in 1/3, with an increased risk of GIST and RCC. One fifth developed malignant disease, requiring comprehensive lifelong tumour screening and surveillance

Pituitary Carcinoma in a Patient with an SDHB Mutation.

We present the first case of pituitary carcinoma occurring in a patient with a succinate dehydrogenase subunit B (SDHB) mutation and history of paraganglioma. She was initially treated for a glomus tumour with external beam radiotherapy. Twenty-five years later, she was diagnosed with a non-functioning pituitary adenoma, having developed bitemporal hemianopia. Recurrence of the pituitary lesion (Ki-67 10% and p53 overexpressed) occurred 5 years after her transsphenoidal surgery, for which she underwent two further operations followed by radiotherapy. Histology showed large cells with vacuolated clear cytoplasm with positive immunostaining for steroidogenic factor 1 (SF1) and negative staining for pituitary hormones. Four years after the pituitary radiotherapy, two metastatic deposits were identified: a foramen magnum lesion and an intradural extra-medullary cervical lesion at the level of C3/C4. There was also significant growth of the primary pituitary lesion with associated visual deterioration. A biopsy of the foramen magnum lesion, demonstrating cells with vacuolated, clear cytoplasm and positive SF1 staining confirmed a pituitary carcinoma, for which she was commenced on temozolomide chemotherapy. There was dramatic clinical improvement after three cycles and reduction in the size of the lesions was observed following six cycles of temozolomide, and further shrinkage after 10 cycles. The plan is for a total of 12 cycles of temozolomide chemotherapy. SDH mutation-related pituitary tumours have an aggressive phenotype which, in this case, led to metastatic disease. SF1 immunostaining was helpful to identify the tissue origin of the metastatic deposit and to confirm the pituitary carcinoma.The Medical College of Saint Bartholomew’s Hospital TrustNIHR (National Institute of Health Research, UK)MRC project grantBritish Neuropathological Societ