Typical CT findings of COVID-19 pneumonia in patients presenting with repetitive negative RT-PCR.

Multiple polymerase chain reaction (RT-PCR) is considered the gold standard diagnostic investigation for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that causes coronavirus disease 2019 (COVID-19). However, false negative multiple polymerase chain reaction (RT-PCR) results can be diagnostically challenging. We report three patients with history of fever and different clinical signs. During the height of the pandemic in Italy (March to May 2020), these patients underwent chest computed tomography (CT) scans that showed lung alterations typical of COVID-19 with multiple negative RT-PCR tests and positive serology for SARS-CoV-2. Two of the three patients showed residual pneumonia on CT after the onset of the first clinical signs. One patient presented with diarrhoea without respiratory symptoms. These cases suggest that in the COVID-19 pandemic period, to provide an earlier specific treatment in patients with positive serology, a chest CT scan can be useful in those presenting with a fever or a history of fever associated with persistent mild respiratory symptoms or with abdominal complaints despite repeated negative RT-PCR results.

Short treatment with the tumour necrosis factor-alpha blocker infliximab diminishes chronic chagasic myocarditis in rats without evidence of Trypanosoma cruzi reactivation.

Tumour necrosis factor (TNF)-alpha is crucial for resistance to Trypanosoma cruzi acute infection, but there is scant information on its role during the chronic phase. To address this issue, we analysed whether a short treatment with a TNF-alpha blocker affected the course and characteristics of chronic disease in a rat experimental model of T. cruzi infection. An anti-TNF-alpha agent (infliximab) was administered during the chronic phase for a period of 4 weeks (3 mg/kg/week), while control infected rats were inoculated with saline physiological solution. Search for parasites yielded non-successful results in all infected groups, irrespective of treatment. Nevertheless, the presence of T. cruzi kDNA in heart tissue was detected in infected and infected plus treated animals. Because infliximab might induce changes in the anti-parasite cytokine response, circulating levels of interleukin (IL)-10, interferon-gamma and nitric oxide were evaluated. An increase in IL-10 levels was observed only in the infected group treated with the anti-TNF-alpha blocker compared to the remaining groups (P < 0.05). A clear attenuation of histological damage associated with a diminution of cardiac TNF-alpha mRNA expression was observed in the infected and treated animals compared to the infected and non-treated group. Blocking of TNF-alpha during a relatively short period in chronically infected rats did not lead to evident parasite reactivation but reduced myocarditis severity significantly, indicating a role of this cytokine in the pathogenesis of chronic myocardial damage.

Improved outcome of Trypanosoma cruzi infection in rats following treatment in early life with suspensions of heat-killed environmental Actinomycetales.

The well-established model of Chagas' disease in "l" rats was used to evaluate the effects of three injections of heat-killed Gordonia bronchialis, Rhodococcus coprophilus or saline on Trypanosoma cruzi parasitaemia and acute and chronic myocarditis, sequelae of the infection. Two vaccinating injections were given prior to challenge with T. cruzi, and the third, immunotherapeutic, injection was given 7 days after challenge. Treatment with either actinomycete significantly reduced acute parasitaemia (p<0.04), modified cellular infiltration during acute myocarditis and limited chronic myocarditis (p<0.03) in comparison with the saline-treated control animals. Immunological investigations showed that both bacterial preparations achieved their results through different mechanisms. The relevance of our findings to human Chagas' disease is discussed.

Sensitization increases esterase-positive macrophage number in appendix from an animal model of food allergy.

BACKGROUND: Macrophages are mononuclear cells with phagocytic and antigen presenting properties. The role of macrophages in IgE-dependent allergic reactions and oral tolerance remains unclear. In previous works we demonstrated that ovalbumin (OVA)-sensitized rabbits present histopathological modifications of the mucosa in different regions of the digestive tract. The present study analyzes macrophage distribution and quantitative modifications in the cecal appendix of OVA-sensitized animals. METHODS: Adult new Zealand rabbits were divided into two groups: G1 (non-sensitized normal controls) and G2 (rabbits sensitized to OVA twice by subcutaneous route, with aluminum hydroxide as adjuvant). The alpha-naphthyl esterase technique was used for macrophage detection. RESULTS: Specific anti-OVA IgE was detected in sensitized animals by the PCA (passive cutaneous anaphylaxis) method. In 5 regions of the cecal appendix we observed a significant increase in the number of macrophages in sensitized animals (G2) versus the control group (G1). The observed sensitization-mediated increase in cells is probably related to enhanced recruitment of monocytes from peripheral blood towards the appendix. This process could be induced by chemical mediators, and demonstrates macrophage participation in local immune response during sensitization phenomena.

Sensitization increases esterase-positive macrophage number in appendix from an animal model of food allergy

Background: Macrophages are mononuclear cells with phagocytic and antigen presenting properties. The role of macrophages in IgE-dependent allergic reactions and oral tolerance remains unclear. In previous works we demonstrated that ovalbumin (OVA)-sensitized rabbits present histopathological modifications of the mucosa in different regions of the digestive tract. The present study analyzes macrophage distribution and quantitative modifications in the cecal appendix of OVA-sensitized animals. Methods: Adult new Zealand rabbits were divided into two groups: G1 (non-sensitized normal controls) and G2 (rabbits sensitized to OVA twice by subcutaneous route, with aluminum hydroxide as adjuvant). The alpha-naphthyl esterase technique was used for macrophage detection. Results: Specific anti-OVA IgE was detected in sensitized animals by the PCA (passive cutaneous anaphylaxis) method. In 5 regions of the cecal appendix we observed a significant increase in the number of macrophages in sensitized animals (G2) versus the control group (G1). The observed sensitization-mediated increase in cells is probably related to enhanced recruitment of monocytes from peripheral blood towards the appendix. This process could be induced by chemical mediators, and demonstrates macrophage participation in local immune response during sensitization phenomena

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The affective dimension of low-back pain: its influence on the outcome of back school.

OBJECTIVE: Back School is a rehabilitation treatment for back pain that requires patients to understand an educational message and motivate themselves to modify their behavior to prevent relapses. In examining failed cases, the question arose as to whether the failures could be attributed to affective dimensions of pain that could be reducing tolerance to the pain itself and jeopardizing patients' compliance. We studied the role of the affective component of back pain in Back School failures to see whether this component can be used to predict the treatment's negative results and whether it can be conditioned by the treatment itself. DESIGN: Inception cohort. SETTING: Forty-two subjects with low back pain were treated with Back School at our rehabilitation department. MAIN OUTCOME MEASURES: Evaluation was carried out before Back School treatment and after 2 months, through functional clinical examination and Short Form-McGill Pain Questionnaire (affective and sensory pain indexes). RESULTS: As outcome of the treatment, we considered the modification of spontaneous and evoked pain and the motility of the spine. Unexpectedly, the nonparametric tests did not show a significant correlation between the affective indicators before and after the treatment. As expected, the two dimensions of pain, affective and sensory, are significantly related to each other, both before and after treatment, but this correlation increases after treatment (from r = .50 to r = 88). CONCLUSIONS: The initial hypothesis was not proven. These results show that high affective scores before Back School do not influence the success of the treatment and that the Back School itself is able to modify both the sensorial and affective pain descriptors.

The learning curve in myopic photorefractive keratectomy.

BACKGROUND: The aim of this study was to assess the role of surgeons' skill on the final results of photorefractive keratectomy (PRK) in the correction of myopia. METHODS: We evaluated the results of 160 consecutive unilateral treatments performed by four surgeons in a multicenter study group, with a one year follow up. Eighty-eight patients were males (55%) and 72 females (45%). Mean age was 33.7 years (median = 33, standard deviation = 10.22, range 18-65). Attempted correction ranged between -1.50 and -15.00 D. All the eyes received topical corticosteroid therapy postoperatively. At the one year follow up, we evaluated the following: uncorrected visual acuity lines gained and refractive error (spherical equivalent) as parameters of efficacy and predictability; best spectacle corrected visual acuity loss and corneal clarity as safety parameters. We also examined the centration or decentration of the ablation zone. In order to draw up a kind of learning curve, the mean values for each parameter were calculated by arbitrarily grouping the first 10 cases of each surgeon in the first group (40 patients), the second 10 cases in the second group (40 patients) and so on. RESULTS: We found that increase in uncorrected visual acuity, final refractive error and corneal clarity appeared to improve as the surgeon became more experienced, while loss of best spectacle corrected visual acuity was not significantly influenced by increased surgical experience. CONCLUSIONS: We think experience with photorefractive keratectomy in at least 40 eyes is necessary to obtain best results.

Excimer laser photorefractive keratectomy for myopia: results in 1165 eyes. Italian Study Group.

BACKGROUND: We report the results of a prospective study conducted in Italy to evaluate the efficacy, safety, predictability, and complications of excimer laser photorefractive keratectomy for the correction of myopia. METHODS. Photorefractive keratectomy was performed on 1236 myopic sighted eyes in 16 centers, using the Summit Excimed 193 nm excimer laser. The attempted correction ranged from -0.80 to -25.00 diopters (mean, -7.83 +/- 3.88 D). The population was divided into three groups of attempted correction: between -0.80 and -6.00 D, between -6.10 and -9.90 D, and between -10.00 and -25.00 D. We report the data of 1165 eyes at 1 month, 970 eyes at 3 months, 752 at 6 months, and 330 at 12 months. At each visit, we evaluated (1) the refractive changes over time; (2) the difference between attempted and achieved correction; (3) uncorrected and best spectacle corrected visual acuity; and (4) haze. RESULTS: Twelve months after surgery, the spherical equivalent refractive error in 146 eyes with attempted correction of -0.80 to -6.00 D was -0.52 +/- 1.04 D; 104 eyes (71.2%) were within +/- 1.00 D of attempted correction. In 145 eyes with attempted correction of -6.10 to -9.90 D, the spherical equivalent refractive error was -1.66 +/- 1.88 D; 50 eyes (34.5%) were within +/- 1.00 D of attempted correction. The spherical equivalent refractive error in 39 eyes with attempted correction of -10.00 to -25.00 D was -1.86 +/- 3.47 D; 11 eyes (28.2%) were within +/- 1.00 D of attempted correction. Eight eyes (2.4%) lost two or more Snellen lines of best spectacle corrected visual acuity. None of the treatments caused severe postoperative complications, or scarring. CONCLUSIONS: Photorefractive keratectomy proved safe and effective, but highly predictable only in the correction of myopia up to -6.00 D.