COVID-19 impedimetric biosensor based on polypyrrole nanotubes, nickel hydroxide and VHH antibody fragment: specific, sensitive, and rapid viral detection in saliva samples.

SARS-CoV-2 rapid spread required urgent, accurate, and prompt diagnosis to control the virus dissemination and pandemic management. Several sensors were developed using different biorecognition elements to obtain high specificity and sensitivity. However, the task to achieve these parameters in combination with fast detection, simplicity, and portability to identify the biorecognition element even in low concentration remains a challenge. Therefore, we developed an electrochemical biosensor based on polypyrrole nanotubes coupled via Ni(OH)2 ligation to an engineered antigen-binding fragment of heavy chain-only antibodies (VHH) termed Sb#15. Herein we report Sb#15-His6 expression, purification, and characterization of its interaction with the receptor-binding domain (RBD) of SARS-CoV-2 in addition to the construction and validation of a biosensor. The recombinant Sb#15 is correctly folded and interacts with the RBD with a dissociation constant (KD) of 27.1 ± 6.4 nmol/L. The biosensing platform was developed using polypyrrole nanotubes and Ni(OH)2, which can properly orientate the immobilization of Sb#15-His6 at the electrode surface through His-tag interaction for the sensitive SARS-CoV-2 antigen detection. The quantification limit was determined as 0.01 pg/mL using recombinant RBD, which was expressively lower than commercial monoclonal antibodies. In pre-characterized saliva, both Omicron and Delta SARS-CoV-2 were accurately detected only in positive samples, meeting all the requirements recommended by the World Health Organization for in vitro diagnostics. A low sample volume of saliva is needed to perform the detection, providing results within 15 min without further sample preparations. In summary, a new perspective allying recombinant VHHs with biosensor development and real sample detection was explored, addressing the need for accurate, rapid, and sensitive biosensors.

Development of polypyrrole (nano)structures decorated with gold nanoparticles toward immunosensing for COVID-19 serological diagnosis.

The rapid and reliable detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) seroconversion in humans is crucial for suitable infection control. In this sense, many studies have focused on increasing the sensibility, lowering the detection limits and minimizing false negative/positive results. Thus, biosensors based on nanoarchitectures of conducting polymers are promising alternatives to more traditional materials since they can hold improved surface area, higher electrical conductivity and electrochemical activity. In this work, we reported the analytical comparison of two different conducting polymers morphologies for the development of an impedimetric biosensor to monitor SARS-CoV-2 seroconversion in humans. Biosensors based on polypyrrole (PPy), synthesized in both globular and nanotubular (NT) morphology, and gold nanoparticles are reported, using a self-assembly monolayer of 3-mercaptopropionic acid and covalently linked SARS-CoV-2 Nucleocapsid protein. First, the novel hybrid materials were characterized by electron microscopy and electrochemical measurements, and the biosensor step-by-step construction was characterized by electrochemical and spectroscopic techniques. As a proof of concept, the biosensor was used for the impedimetric detection of anti-SARS-CoV-2 Nucleocapsid protein monoclonal antibodies. The results showed a linear response for different antibody concentrations, good sensibility and possibility to quantify 7.442 and 0.4 ng/mL of monoclonal antibody for PPy in the globular and NT morphology, respectively. The PPy-NTs biosensor was able to discriminate serum obtained from COVID-19 positive versus negative clinical samples and is a promising tool for COVID-19 immunodiagnostic, which can contribute to further studies concerning rapid, efficient, and reliable detections.

[Perineal groove: Case report and review of the literature]. / Rainure périnéale congénitale : à propos d'un cas.

Perineal groove is a rare anoperineal congenital malformation, usually occurring in girls, unknown to many pediatricians. We report the case of a 17-day-old girl admitted for urinary infection, who presented a wet sulcus with mucous membrane, extending from the vaginal fourchette to the anterior border of the anus. The diagnosis of perineal groove was clinically confirmed, after elimination of misdiagnosis such as infection or trauma. This benign malformation tends to be self-epithelialized in the 1st year of life, and no surgical treatment is recommended, except for cosmetic reasons or for recurrent infections. This diagnosis must be known so as to avoid unnecessary explorations and anxiogenic misdiagnosis.

A complex proximal femoral fracture.

We present the case of a 39-year-old sportswoman who was involved in a motorcycle accident in 2012. She sustained a complex proximal femoral fracture that involved the neck and trochanteric region. We decided to preserve the natural bone stock and repair the fractures, adopting skeletal traction in the first stage and then implanting an intramedullary nail. Twenty months later the fracture was healed clinically and radiologically and the patient was able to walk and run without pain.

Aquagenic (pseudo) keratoderma: a clinical series with new pathological insights.

BACKGROUND: Aquagenic keratoderma is an uncommon condition that occurs after brief water exposure. An association with cystic fibrosis has been suggested. Histopathology is considered to be nonspecific. OBJECTIVES: To describe the microscopic findings in seven of 12 new patients and compare the histopathological results of the lesions which appeared on the palmar skin after immersion into water with normal skin. PATIENTS AND METHODS: Nine female and three male patients (mean age 27 years) were collected prospectively and evaluated for common demographic, clinical and histopathological features. RESULTS: Lesions were located on only the palms in seven patients; the soles were involved in two patients; and one patient had involvement of the dorsal aspect of the hands. One patient had a similar family history. None of the patients reported associated conditions. Genetic studies revealed heterozygosis for mutation in the cystic fibrosis gene in two patients. The most specific histopathological findings were: orthohyperkeratosis with increased thickness and abnormal staining of the stratum corneum; dilated acrosyringia and dermal eccrine ducts with hyperplasia of eccrine glands, clear cell change and vacuolation; increased capillaries around and adjacent to the eccrine glands. A skin biopsy taken after restoration of normal skin with drying revealed a normal stratum corneum with a physiological uniform stain and normal thickness without further evidence of dilation of acrosyringia or dermal eccrine ducts. Incipient dilation of the secretory and ductal structures was also observed in a transitional area between the involved and the clinically normal skin of the palms. CONCLUSIONS: Aquagenic keratoderma may be associated with a heterozygous mutation in the cystic fibrosis gene. Although the diagnosis is a clinical one, histopathology is useful and may reveal some characteristic diagnostic clues. Aquagenic pseudokeratoderma seems to be a more appropriate term to name it.

Investigation of electrochemical degradation process in polyaniline/polystyrene sulfonated self-assembly films by impedance spectroscopy.

In this study, the electrochemical degradation of polyaniline/polystyrene sulfonated (PANI/PSS) self-assembly films was investigated by an electrochemical impedance technique using transmission line models to fit the results. The experiments were performed by polarizing the working electrode at a fixed oxidative potential of 0.55 V. The results showed that changes in the electrochemical behavior of the oxidized PANI/PSS film occurred mainly in the polymer/solution interface by an increase in the charge transfer resistance.

Investigation of polypyrrole degradation using electrochemical impedance spectroscopy.

In this paper, the electrochemical degradation of polypyrrole film was studied by means of overpotential application. The overpotential was 0.58 V versus SCE, and after every 5 min of application of 0.58 V, a cyclic voltammogram was recorded in the range of -0.7 to 0.5 V as well as an electrochemical impedance spectroscopy and electrochemical quartz crystal microbalance (EIS and EQCM). The main characteristic is the huge increase in the charge transfer resistance (r(ct)), which indicates that the insertion process of ions in the polymer matrix is hindered by the electrochemical degradation. Once the process of insertion is damaged, the number of intercalated ions in the matrix should decrease, which is expressed by the low-frequency capacitance, which is proportional to the number of intercalated ions in the polymeric matrix. The decrease of intercalated ions has an influence in the mass variation of the polymer film, which is confirmed by EQCM measurements.

Clinical and histopathological risk factors to predict sentinel lymph node positivity, disease-free and overall survival in clinical stages I-II AJCC skin melanoma: outcome analysis from a single-institution prospectively collected database.

BACKGROUND: To investigate if the tumour infiltrating lymphocytes (TILs) are able to predict the sentinel lymph node (SLN) positivity, the disease-free survival (DFS) and overall survival (OS) in clinical stages I-II AJCC primary cutaneous melanoma (PCM). METHODS: The study included consecutive patients with PCM, all diagnosed, treated and followed up prospectively. Logistic regression was used to investigate the association between DFS, OS, SLN positivity and Breslow thickness, Clark level, TIL, ulceration, lesion site, gender, regression and age. RESULTS: From November 1998 to October 2008, 1251 consecutive patients with PCM were evaluated. Median age was 51 (range 15-96) with 32.2% (N=393) of them older than 60; 44.8% of them were males. Of the whole series, a total of 404 patients with primary vertical growth phase (VGP) melanoma and no clinical evidence of metastatic disease underwent SLN biopsy. Of these, 74 (18.8%) had a positive SLN. In a multivariate analysis, primary melanoma on the extremities versus that on the axial locations (truncal and head/neck) (OR 0.49, 95% CI 0.25-0.98, p 0.04) and TILs (TILs versus no TILs) (OR 0.47, 95%CI 0.25-0.90, p 0.02) were predictive for lower probability of SLN involvement, while thickness (>4mm versus 0-1mm) (OR 24, 19, 95% CI 4.91-119.13, p<.001) was predictive for higher risk of SLN positivity. A multivariate stepwise analysis confirmed these results. The histological status of the SLN was the most significant predictor of DFS and OS. Patients with a negative SLN had a 5-year DFS of 75.9%, compared with 35.2% in patients with a positive SLN (p<.0001) and a 5-year OS of 88.7% versus 42.9%, respectively (p<.0001). CONCLUSIONS: Our study demonstrates that the absence of TILs predicts SLN metastasis, in multivariate analysis the SLN positivity predicts DFS and OS.

Randomized controlled trial comparing the effectiveness of 308-nm excimer laser alone or in combination with topical hydrocortisone 17-butyrate cream in the treatment of vitiligo of the face and neck.

BACKGROUND: Vitiligo is a pigmentary disorder which may have disfiguring consequences. Its treatment remains a challenge. OBJECTIVES: We designed a parallel-group randomized controlled trial to compare the effectiveness of 308-nm excimer laser alone or in combination with topical hydrocortisone 17-butyrate cream in patients with vitiligo unresponsive to previous treatment with topical steroids or narrow-band ultraviolet (UV) B phototherapy. METHODS: Consecutive patients aged 18-75 years with nonsegmental vitiligo localized on the face and/or neck lacking response to previous conventional treatment were eligible. In total, 84 patients (44 women and 40 men, mean age 44 years) were randomized to 308-nm excimer laser phototherapy twice weekly alone or in combination with topical hydrocortisone 17-butyrate cream twice daily for three periods of 3 weeks followed by a 1-week steroid-free interval. The primary outcome was a reduction of at least 75% of the overall lesional areas as judged by automatic image analysis on reflected UV photographs, conducted blind to treatment assignment, at 12 weeks compared with baseline. Secondary outcomes were clearance, and improvements on Physician's Global Assessment (PGA) and Skindex-29 scores. RESULTS: A total of 76 (90%) patients completed the study. In an intention-to-treat analysis, seven [16.6%; 95% confidence interval (CI) 5.3-27.8%] patients in the excimer monotherapy arm and 18 (42.8%; 95% CI 27.8-57.8%) in the combination arm showed > or = 75% reduction of vitiligo lesions at 12 weeks (chi(2) test 6.89, P = 0.0087). Clearance was observed in two (4.7%; 95% CI 1.6-11.2%) and nine (21.4%; 95% CI 9.0-33.8%) patients, respectively (Fisher's exact test P = 0.04). A significant difference also emerged for PGA scores, while no difference was documented for Skindex-29. CONCLUSIONS: Recalcitrant vitiligo of the face and neck may benefit from the combination of excimer laser phototherapy with topical hydrocortisone 17-butyrate cream.

Tinea capitis due to Trichophyton soudanense with a papular IDE reaction in Northern Italy.

A little boy from a Nigerian family who lives in a little industrialized village in the suburbs of Bergamo, (Northern Italy), has never been to his country but presented with tinea capitis and with a secondary papular pruritic eruption of the trunk. Fungal cultures analysis have shown the development of Trichophyton soudanense, an anthropophilic dermatophyte which is endemic in Africa, but only rarely reported in Italy and in other European countries. The growing racial mixing related to migratory movements is favoring, also in Italy, the integration of this strain with the species which are most commonly responsible for dermatophytoses and the appearance of papular IDE reactions which were only occasionally seen in the Italian children population.

Phakomatosis pigmentovascularis: A new case with renal angiomas and some considerations about the classification.

We report phakomatosis pigmentovascularis detected in a Caucasian child characterized by the presence of a nevus flammeus and nevus anemicus on the face, a telangiectatic linear nevus of the right leg, and a very extensive blue spot covering 60% of the body surface, with ocular melanosis. Multiple angiomatous lesions of the kidney are associated without alterations of the central nervous system (CNS). This association has not been reported before; it could be a further expression of the complex of developmental defects. Our case corresponds exactly to type IIb in the classification of phakomatosis pigmentovascularis proposed by Hasegawa. As this classification seems very extensive, the higher incidence of cases corresponding to the second subtype suggests that we should identify it by the term phakomatosis pigmentovascularis, while the others could be considered as only very uncommon variants.

A case of hypopigmented mycosis fungoides in a young Caucasian boy.

Hypopigmented mycosis fungoides is a variant of mycosis fungoides characterized by the presence of hypopigmented patches as the sole manifestation of the disease. It has been described almost always in young black or dark-skinned patients. The only white patient described was a 64-year-old woman who not only had hypopigmented lesions, but also nodular lesions with lymphadenopathy. We describe hypopigmented lesions arising in a white boy 12 years of age, born in northern Italy, without any foreign ancestors. The microscopic alterations, with epidermotropism, the immunologic markers, the negativity of T-cell receptor gene rearrangement, and the good response to PUVA therapy correspond to the main findings in black patients with this disease. Long-term follow-up of these patients is important to obtain better knowledge of the natural history of the disorder. Hypopigmented mycosis fungoides must now be included in the differential diagnosis of hypopigmented macular lesions not only in black or dark-skinned patients but also in white patients.

Combined Clark's nevus.

We report five cases of combined Clark's nevi. Like all melanocytic nevi, Clark's nevus can combine with other nevi to produce lesions that are hard to interpret clinically and histologically. The morphology of combined Clark's nevus can resemble that of a melanoma associated with a nevus.

[Subcutaneous phaeohyphomycose due to Exophiala jeanselmir. Report of 3 cases in patients with a kidney transplant]. / Feo-hifomicose subcutânea por Exophiala jeanselmei. Registro de três casos em transplantados renais.

We report three cases of subcutaneous phaeohyphomycosis due to Exophiala jeanselmei (Langeron) McGinnis et Padhye 1977, in kidney transplant patients. Exophiala jeanselmei is a dematious fungus having also ability to rarely procedure eumycetoma (black grains). According to KWON-CHUNG & BENNETT (1992) such fungus is antigenically very heterogeneous, since so far three serotypes have been identified; each serotype including subgroups. Subcutaneous phaeohyphomycosis is becoming more and more frequent in kidney transplant patients submitted to an immunosuppressive treatment. As Exophiala jeanselmei has already been isolated from the environment it becomes difficult to explain the pathogenicity of these cases by a reactivation of quiescent processes. The authors suggest an occasional fungistatic action of cyclosporine A upon Exophiala jeanselmei.

Cutaneous malignant melanoma appearing during photochemotherapy of mycosis fungoides.

We report a case of malignant melanoma that appeared in a 56-year-old man with mycosis fungoides (stage Ia) during treatment with PUVA. The cumulative UVA dose was 1,177 J/cm2. The pigmented lesion was removed and PUVA therapy discontinued. Histological examination revealed a superficial spreading malignant melanoma (1.77 mm thick, Clark level IV). The delayed-type cutaneous hypersensitivity was studied. The presence of a second malignancy after mycosis fungoides and PUVA therapy may have been coincidental. Nevertheless, this case suggests that the immunosuppression induced by mycosis fungoides and by PUVA therapy might be a pathogenetic factor in the development of malignant melanoma.

Agminate blue nevus combined with lentigo. A variant of speckled lentiginous nevus?

We report a case of agminate blue nevus combined with a lentigo patch in a 38-year-old woman. The combination was interpreted as a unique and peculiar variant of speckled lentiginous nevus.