On adaptive security of delayed-input sigma protocols and fiat-shamir nizks

We study adaptive security of delayed-input Sigma protocols and non-interactive zero-knowledge (NIZK) proof systems in the common reference string (CRS) model. Our contributions are threefold:We exhibit a generic compiler taking any delayed-input Sigma protocol and returning a delayed-input Sigma protocol satisfying adaptive-input special honest-verifier zero knowledge (SHVZK). In case the initial Sigma protocol also satisfies adaptive-input special soundness, our compiler preserves this property.We revisit the recent paradigm by Canetti et al. (STOC 2019) for obtaining NIZK proof systems in the CRS model via the Fiat-Shamir transform applied to so-called trapdoor Sigma protocols, in the context of adaptive security. In particular, assuming correlation-intractable hash functions for all sparse relations, we prove that Fiat-Shamir NIZKs satisfy either: (i)Adaptive soundness (and non-adaptive zero knowledge), so long as the challenge is obtained by hashing both the prover’s first round and the instance being proven;(ii)Adaptive zero knowledge (and non-adaptive soundness), so long as the challenge is obtained by hashing only the prover’s first round, and further assuming that the initial trapdoor Sigma protocol satisfies adaptive-input SHVZK.We exhibit a generic compiler taking any Sigma protocol and returning a trapdoor Sigma protocol. Unfortunately, this transform does not preserve the delayed-input property of the initial Sigma protocol (if any). To complement this result, we also give yet another compiler taking any delayed-input trapdoor Sigma protocol and returning a delayed-input trapdoor Sigma protocol with adaptive-input SHVZK. An attractive feature of our first two compilers is that they allow obtaining efficient delayed-input Sigma protocols with adaptive security, and efficient Fiat-Shamir NIZKs with adaptive soundness (and non-adaptive zero knowledge) in the CRS model. Prior to our work, the latter was only possible using generic NP reductions

Somatostatin receptor scintigraphy using (99m)Tc-EDDA/YNIC-TOC in patients with medullary thyroid carcinoma.

Purpose Several new somatostatin analogues have been developed for the diagnosis and therapy of different tumours. Since somatostatin receptors are often over-expressed in medullary thyroid carcinoma (MTC), the aim of our study was to evaluate the utility of scintigraphy with the somatostatin analogue (99m)Tc-EDDA/HYNIC-TOC in MTC in comparison with other diagnostic techniques. Methods Forty-five patients with MTC, aged 14-83 years, were investigated. Scintigraphy using (99m)Tc-EDDA/HYNIC-TOC (Tektrotyd) was performed 2 and 4 h post injection of 740 MBq (20 mCi) of the tracer. Other imaging techniques were also applied and analysed in individual cases (ultrasonography, computed tomography, (99m)Tc(V)-DMSA, (131)I-MIBG, (99m)Tc-MDP, (111)In-DTPA-octreotide and (18)F-FDG-PET) and compared with (99m)Tc-EDDA/HYNIC-TOC. Results In group 1 (eight patients before thyroidectomy), uptake of the tracer was found in the primary tumours. In group 2 (six patients with remission), a false positive result was found in one patient; in the remaining five patients, no pathological foci were visualised. In group 3 (31 patients with post-surgical hypercalcitoninaemia), scintigraphy was true positive in 23 patients (74.2%): uptake in the thyroid bed was found in five patients, in the lymph nodes in 18 and in bone metastases in four. Using (99m)Tc-EDDA/HYNIC-TOC scintigraphy, the overall sensitivity was 79.5%, specificity 83.3%, accuracy 80.0%, positive predictive value 96.9% and negative predictive value 38.5%. Conclusion (99m)Tc-EDDA/HYNIC-TOC is clinically useful for scintigraphy in the follow-up of patients with MTC. It can be used in clinical practice for preoperative evaluation, for localisation of local recurrence or distant metastases and particularly for therapy decision making

In vivo imaging of insulitis in autoimmune diabetes

[No abstract available

Clinical indications to the use of Tc-99m-EDDA/HYNIC-TOC to detect somatostatin receptor-positive neuroendocrine tumors

The aim of this study was to define, retrospectively, the utility to perform Tc-99m-EDDA/HYNIC-Tyr3-octreotide (Tc-99m-EDDA/HYNIC-TOC) scan in patients with NET. We studied 50 consecutive patients affected by different types of NET and divided in two groups. Group 1: 34 patients with known lesions in which Tc-99m-EDDA/HYNIC-TOC was performed for staging, characterisation or to choose the appropriate treatment. Group 2: 16 patients suspected of having NET or in follow up after surgery. Patients were injected with 370 MBq of Tc-99m-EDDA/HYNIC-Tyr3-octreotide and whole-body and SPET images acquired 2-3 hours after injection. Overall, 29 patients (58%) had a positive scan, with a sensitivity, specificity and accuracy of 70.3%, 76.9% and 72%, respectively (78.1%, 50% and 76.5%, in group 1 and 20%, 81.2%, 62.5% in group 2). In patients from group 1 Tc-99m-HYNIC-TOC scintigraphy showed a concordance of 68% with another imaging procedure and in 9 patients revealed a greater number of lesions. In the second group, false negative results were especially found in patients with medullary thyroid cancer with negative radiological findings and elevated calcitonin. In conclusion, Tc-99m-EDDA/HYNIC-TOC is highly indicated for in vivo histological characterization of known NET lesions, previously identified by other imaging modalities or biopsy, to plan appropriate therapy especially for patients with inoperable disease. In patients with only biochemical suspicion of NET and in those with negative markers, this scintigraphy does not significantly modify the clinical management

Clinical indications to the use of 99mTc-EDDA/HYNIC-TOC to detect somatostatin receptor-positive neuroendocrine tumors.

The aim of this study was to define, retrospectively, the utility to perform 99mTc-EDDA/HYNIC-Tyr3-octreotide (99mTc-EDDA/HYNIC-TOC) scan in patients with NET. We studied 50 consecutive patients affected by different types of NET and divided in two groups. Group 1: 34 patients with known lesions in which 99mTc-EDDA/HYNIC-TOC was performed for staging, characterisation or to choose the appropriate treatment. Group 2: 16 patients suspected of having NET or in follow up after surgery. Patients were injected with 370 MBq of 99mTc-EDDA/HYNIC-Tyr3-octreotide and whole-body and SPET images acquired 2-3 hours after injection. Overall, 29 patients (58\%) had a positive scan, with a sensitivity, specificity and accuracy of 70.3\%, 76.9\% and 72\%, respectively (78.1\%, 50\% and 76.5\%, in group 1 and 20\%, 81.2\%, 62.5\% in group 2). In patients from group 1 99mTc-HYNIC-TOC scintigraphy showed a concordance of 68\% with another imaging procedure and in 9 patients revealed a greater number of lesions. In the second group, false negative results were especially found in patients with medullary thyroid cancer with negative radiological findings and elevated calcitonin. In conclusion, 99mTc-EDDA/HYNIC-TOC is highly indicated for in vivo histological characterization of known NET lesions, previously identified by other imaging modalities or biopsy, to plan appropriate therapy especially for patients with inoperable disease. In patients with only biochemical suspicion of NET and in those with negative markers, this scintigraphy does not significantly modify the clinical management

Cross-elicitation responses to 2-methoxymethyl-p-phenylenediamine in p-phenylenediamine highly allergic volunteers using allergy alert test: the italian experience

Background. Allergic contact dermatitis after exposure to p-phenylenediamine (PPD)-contain-ing hair dye products is a common and important clinical problem. Because there is a high rate of cross-elicitation of allergic contact dermatitis to other important hair dye products (such as p-toluene diamine [PTD] and other aminophenol hair dyes) in PPD allergic patients, safer alternative dyes with excellent hair coloring options are needed. We studied 2-methoxy meth-yl-PPD (Me-PPD), a chemical derivative of PPD for tolerance versus cross-elicitation in a cohort of eight PPD-allergic volunteers. Objective. To study tolerance to Me-PPD in a PPD highly allergic Italian cohort. Methods. Eight volunteers with a history of contact dermatitis to hair dyes or other PPD-containing chemicals and positive patch tests to 1% PPD in petrolatum, were recruited to study their immediate and delayed skin reactivity to PPD, vehicle control and 2-me-thoxy-methyl-PPD (Me-PPD), using the allergy alert test (simulating hair dyeing conditions) on volar forearm skin. This is a short-contact open patch test. Results. All eight volunteers reacted to PPD allergy alert test (100%); none reacted to vehicle (0%), and seven of eight reacted to Me-PPD allergy alert test (88%). However, in those seven volunteers who exhibited cross-elicitation to Me-PPD, their aggregate skin test reactivity to Me-PPD was significantly less than that of PPD (figure 3, p < 0.0062, highly significant, paired two-tailed, students t test). Conclusions. Me-PPD may offer a safer alternative for PPD-allergic patients with an absent or reduced elicitation response in the allergy alert test simulating hair dye use conditions. Even patients with strong patch test reactions, with appropriate selection by allergy alert test and counselling, may be able to tolerate hair dyeing with Me-PPD containing products

Cross-elicitation responses to 2-methoxymethyl-p-phenylenediamine in p-phenylenediamine highly allergic volunteers using allergy alert test: the Italian experience

Summary: Background. Allergic contact dermatitis after exposure to p-phenylenediamine (PPD)-containing hair dye products is a common and important clinical problem. Because there is a high rate of cross-elicitation of allergic contact dermatitis to other important hair dye products (such as p-toluene diamine [PTD] and other aminophenol hair dyes) in PPD allergic patients, safer alternative dyes with excellent hair coloring options are needed. We studied 2-methoxy methyl-PPD (Me-PPD), a chemical derivative of PPD for tolerance versus cross-elicitation in a cohort of eight PPD-allergic volunteers. Objective. To study tolerance to Me-PPD in a PPD highly allergic Italian cohort. Methods. Eight volunteers with a history of contact dermatitis to hair dyes or other PPD-containing chemicals and positive patch tests to 1% PPD in petrolatum, were recruited to study their immediate and delayed skin reactivity to PPD, vehicle control and 2-methoxy-methyl-PPD (Me-PPD), using the allergy alert test (simulating hair dyeing conditions) on volar forearm skin. This is a short-contact open patch test. Results. All eight volunteers reacted to PPD allergy alert test (100%); none reacted to vehicle (0%), and seven of eight reacted to Me-PPD allergy alert test (88%). However, in those seven volunteers who exhibited cross-elicitation to Me-PPD, their aggregate skin test reactivity to Me-PPD was significantly less than that of PPD (figure 3, p minore 0.0062, highly significant, paired two-tailed, students t test). Conclusions. Me-PPD may offer a safer alternative for PPD-allergic patients with an absent or reduced elicitation response in the allergy alert test simulating hair dye use conditions. Even patients with strong patch test reactions, with appropriate selection by allergy alert test and counselling, may be able to tolerate hair dyeing with Me-PPD containing products