A PCR-based method for the diagnosis of Enterobius vermicularis in stool samples, specifically designed for clinical application.

Background: Enterobius vermicularis (E. vermicularis) is a nematode that infects up to 200 million people worldwide, despite effective medications being available. Conventional diagnostic tests are hindered by low sensitivity and poor patient compliance. Furthermore, no biomolecular techniques are available for clinical application. The aim of this study was to develop a procedure specifically designed for clinical application to detect E. vermicularis by means of PCR. Materials and methods: Two subject groups were taken into account: a group of 27 infected patients and a control group of 27 healthy subjects. A nested-PCR was performed on fecal samples to detect E. vermicularis. Due to the intrinsic difficulties of the fecal matrix, several countermeasures were adopted to ensure the efficient performance of the method: (a) a large amount of feces for the extraction process (20 g instead of 200 mg); (b) a combination of chemical and physical treatments to grind the fecal matrix; (c) an additional purification process for the negative samples after the first nested-PCR; and (d) the selection of a very specific target region for the PCR. Results: Due to the lack of overlap with other organisms, a sequence of the 5S ribosomal DNA (rDNA) spacer region including the tract SL1 was chosen to design appropriate external and internal primers. The first nested-PCR detected E.vermicularis in 19/27 samples from infected patients. After further purification, 5/8 of the negative samples resulted positive at the second PCR. Conversely, all the samples from healthy controls resulted negative to both PCRs. Sensitivity and specificity of the method were, respectively, 88.9% and 100%. Conclusion: The results prove the high diagnostic accuracy of the proposed method, addressing and overcoming the challenges posed by both conventional tests and PCR-based approaches. Therefore, the method can be proposed for clinical application.

Structural equation modeling to shed light on the controversial role of climate on the spread of SARS-CoV-2.

Climate seems to influence the spread of SARS-CoV-2, but the findings of the studies performed so far are conflicting. To overcome these issues, we performed a global scale study considering 134,871 virologic-climatic-demographic data (209 countries, first 16 weeks of the pandemic). To analyze the relation among COVID-19, population density, and climate, a theoretical path diagram was hypothesized and tested using structural equation modeling (SEM), a powerful statistical technique for the evaluation of causal assumptions. The results of the analysis showed that both climate and population density significantly influence the spread of COVID-19 (p < 0.001 and p < 0.01, respectively). Overall, climate outweighs population density (path coefficients: climate vs. incidence = 0.18, climate vs. prevalence = 0.11, population density vs. incidence = 0.04, population density vs. prevalence = 0.05). Among the climatic factors, irradiation plays the most relevant role, with a factor-loading of - 0.77, followed by temperature (- 0.56), humidity (0.52), precipitation (0.44), and pressure (0.073); for all p < 0.001. In conclusion, this study demonstrates that climatic factors significantly influence the spread of SARS-CoV-2. However, demographic factors, together with other determinants, can affect the transmission, and their influence may overcome the protective effect of climate, where favourable.

Selected case from the Arkadi M. Rywlin international pathology slide series: diffuse dendriform pulmonary ossification: report of 2 cases with review of the literature.

Two cases of diffuse dendriform pulmonary ossification (DPO) are presented, one of the secondary type and the other of the idiopathic type. Case 1 was an adult female patient who underwent thoracic surgery to remove a posterior mediastinal bronchogenic cyst, which was discovered on a computed tomography scan performed after an episode of pneumonia when traction bronchiectasis with interstitial lung disease/fibrosis was also suspected in the lungs. Histologic examination performed on the resected lung tissue revealed numerous scattered small osseous spicules on a background of intense interstitial inflammation and fibrosis, leading to further clinical and laboratory investigations and the final diagnosis of DPO secondary to lung involvement by scleroderma. Case 2 was an adult male patient who underwent thoracoscopic exploration after a computed tomography scan, which revealed traction bronchiectasis with linear thickening of the interstitial lung tissue. Histologic examination of the lung tissue specimen revealed numerous osseous spicules in the absence of interstitial septal inflammation. Noteworthy in this case were also some nodules of collagenized tissue similar to those seen in the lungs of patients affected by Ehlers-Danlos syndrome. The absence of any clinical sign or symptoms related to Ehlers-Danlos syndrome attest to the nonspecificity of these pulmonary fibrous nodules. No case of DPO secondary to scleroderma has been reported in the literature so far, although around half of the patients with scleroderma manifest pulmonary diseases. Idiopathic DPO is even rarer, usually discovered postmortem, with only 20 cases diagnosed in life with lung biopsies taken by open surgery or through a thoracoscopic approach. DPO is often misdiagnosed radiologically as bronchiectasis and/or interstitial lung disease/fibrosis.

Primary malignant melanoma of the esophagus: a clinicopathologic study of a case with comprehensive literature review.

Primary malignant melanoma originating in the digestive tract is particularly rare, mainly affecting the anorectum and oral cavity. Primary malignant melanoma of the esophagus has been the subject mostly of case reports. This tumor has a dismal prognosis with a frequency estimated to be approximately 0.1% to 0.2% of all esophageal malignancies. According to the review by Volpin et al of November 2002, 238 cases of primary malignant melanoma of the esophagus have been published up to early 2001. We present an additional case of primary malignant melanoma of the esophagus of the amelanotic variant in a 69-year-old man. The patient was preoperatively investigated by esophageal endoscopy and endoscopic ultrasound. The surgically resected tumor specimen was examined histologically and supplemented by immunohistochemical and ultrastructural analysis. Intra-abdominal relapse occurred after 8 months at the site of surgery, necessitating repeat resection. The patient died of advanced intra-abdominal disease 14 months after the primary diagnosis. A comprehensive computerized (PubMed/Medline) review of the world literature was also carried out and 99 additional cases (after the review by Volpin et al) were found, 9 of them from the 1990s which escaped previous tabulations, and 90 from the years 2000 to 2010, amounting to a grand total of 337 ever published.

Clinical usefulness of gastric-juice analysis in 2007: the stone that the builders rejected has become the cornerstone.

BACKGROUND: Gastric juice is usually discarded during upper-GI endoscopy. OBJECTIVE: By using a novel device, the Mt 21-42, we evaluated the potential of this important organic fluid in clinical practice, exploring its contribution to the diagnosis of Helicobacter pylori infection and atrophic gastritis of the oxyntic mucosa (AGOM). DESIGN AND PATIENTS: A multicenter study (17,907 patients; 10 endoscopy units) estimated the frequency of diagnosis of AGOM and H pylori infection in routine endoscopic practice. A prospective study (216 patients) at 1 of these units aimed to determine the real prevalence of these conditions and the possible benefits of gastric juice analysis. We considered gastric juice pH and ammonium concentration, endoscopic and histologic features, serologic parameters for atrophy and H pylori, gastric acid secretion, and costs. RESULTS: We found that H pylori infection and, even more markedly, AGOM were greatly underdiagnosed in routine endoscopic practice (20.1% and 0.8% vs 49.1% and 12.5% in the prospective study, respectively), because of the intrinsic limitations of the conventional tests and lack/inappropriateness of biopsy planning. Gastric-juice analysis proved to be a cheap, simple, and effective way to prevent such underdiagnosis and allowed detection of atrophic gastritis and H pylori in 96% and 98% of cases, and saved costs (cost-effectiveness ratio 209 vs 274-5047). CONCLUSIONS: Gastric juice provided a valuable source of clinicopathologic information that, properly analyzed, allowed detection of the main risk factors for gastric cancer (H pylori and atrophic gastritis), overcoming the diagnostic limitations associated with these conditions and also producing time and cost savings.

Mt 21-42: development and validation of an automatic device proposed for the endoscopic diagnosis of Helicobacter pylori infection and atrophic gastritis.

BACKGROUND: Gastric juice may give important clinico-pathological information, but measurements in this medium are difficult. In this study we present and validate an innovative device (Mt 21-42) performing gastric juice analyses during endoscopy and proposed for the endoscopic diagnosis of Helicobacter pylori infection and hypo/achlorhydria. METHODS: Analyses on both aqueous solutions (80 pH buffer + 120 ammonium chloride samples) and human gastric juice were carried out to assess the measuring performance of Mt 21-42 on the ideal and real matrix, respectively. Matrix spike and manipulation tests were also performed to investigate the matrix effect of gastric juice and to evaluate the consequences of its manipulation on the measurements. Furthermore, preliminary clinical tests were performed to evaluate the clinical potentiality of the device. RESULTS: Mt 21-42 showed a good measuring performance on ideal matrix (coefficient variation: pH = 1.3%, ammonium = 2.1%) and real matrix (coefficient variation: pH = 1.2%, ammonium = 1.9%). Analyses on gastric juice excluded a substantial matrix effect (percent recovery =96.5-98.7%) but demonstrated a significant influence of manipulation procedures (p < 0.05). CONCLUSIONS: Human gastric juice does not have a substantial matrix effect for pH and ammonium determination, but its manipulation may affect the measurement of these components. Mt 21-42 represents a precise instrument for the measurement of gastric juice and a potential precious tool for the endoscopic detection of H. pylori infection and hypo/achlorhydric conditions.