Noise-induced tinnitus: auditory evoked potential in symptomatic and asymptomatic patients

OBJECTIVES:

We evaluated the central auditory pathways in workers with noise-induced tinnitus with normal hearing thresholds, compared the auditory brainstem response results in groups with and without tinnitus and correlated the tinnitus location to the auditory brainstem response findings in individuals with a history of occupational noise exposure.

METHOD:

Sixty individuals participated in the study and the following procedures were performed: anamnesis, immittance measures, pure-tone air conduction thresholds at all frequencies between 0.25–8 kHz and auditory brainstem response.

RESULTS:

The mean auditory brainstem response latencies were lower in the Control group than in the Tinnitus group, but no significant differences between the groups were observed. Qualitative analysis showed more alterations in the lower brainstem in the Tinnitus group. The strongest relationship between tinnitus location and auditory brainstem response alterations was detected in individuals with bilateral tinnitus and bilateral auditory brainstem response alterations compared with patients with unilateral alterations.

CONCLUSION:

Our findings suggest the occurrence of a possible dysfunction in the central auditory nervous system (brainstem) in individuals with noise-induced tinnitus and a normal hearing threshold.     

Proteaese activity of Blastocystis hominis subtype3 in symptomatic and asymptomatic patients

Despite accumulating evidence indicating that Blastocystis hominis is pathogenic and that cysteine proteases are involved in its pathogenesis, few researches discussed the protease activity of B. hominis genetic subtypes. Therefore, the present study aims to identify the underlying pathogenic role of the proteases of B. hominis subtype 3 at different molecular weights in correlation to gastrointestinal symptoms. Of 65 patients with various clinical presentations referred to our laboratory for stool examination, 26 (40%) were B. hominis positive by stool culture. Of 26 (group I) B. hominis patients, 18 (69.2%) were symptomatic (group IA) and 8(30.8%) were asymptomatic (group IB). Of 25 normal control group (group II), 5 (20%) were B. hominis positive. Subtype 3 was the only genotype recovered by polymerase chain reaction. Of 26 patients in group I, 19 (73.1%) were immunocompetent and 7 (26.9%) were immunocompromised. Protease activities of B. hominis subtype 3 were recognized at 32-kDa (46.2%), 39-kDa (7.7%), 120-kDa (38.5%), 140-kDa (11.5%), and 215-kDa (19.2%) bands in gelatin sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Proteases were recognized in 17 (94.4%) out of 18 symptomatic Blastocystis patients versus 2 (25.0%) out of 8 asymptomatic patients. Proteases at 32 kDa were reported in 61.1% of symptomatic versus 12.5% of asymptomatic patients. It was concluded that proteases of B. hominis genetic subtype 3, particularly those at 32 kDa, could be considered a virulence factor that is responsible for protein degradation and have a possible pathogenic role in host immune evasion.     

Clinical characteristics of asymptomatic and symptomatic patients with mild COVID-19

ObjectivesDetailed knowledge on the prevalence of asymptomatic cases of coronavirus disease 2019 (COVID-19) and the clinical characteristics of mild COVID-19 is essential for effective control of the COVID-19 pandemic. We determined the prevalence of asymptomatic cases of COVID-19 and characterized the symptoms of patients with mild COVID-19.MethodsStudy participants were recruited from a community facility designated for the isolation of patients without moderate-to-severe symptoms of COVID-19 in South Korea. The prevalence of asymptomatic patients at admission and the detailed symptoms of mild COVID-19 were evaluated through a questionnaire-based survey. Diagnosis of COVID-19 was confirmed by real-time RT-PCR.ResultsOf the 213 individuals with COVID-19, 41 (19.2%) were asymptomatic until admission. Among the remaining patients with mild COVID-19, the most common symptom was cough (40.1%; 69/172), followed by hyposmia (39.5%; 68/172) and sputum (39.5%; 68/172). Of the 68 individuals with hyposmia, 61 (90%) had accompanying symptoms such as hypogeusia, nasal congestion or rhinorrhoea. Fever (>37.5°C) was only observed in 20 (11.6%) individuals.ConclusionsAs much as one-fifth of individuals with COVID-19 remained asymptomatic from exposure to admission. Hyposmia was quite frequent among individuals with mild COVID-19, but fever was not. Social distancing should be strongly implemented to prevent disease transmission from asymptomatic individuals or those with mild and inconspicuous symptoms.     

In vivo validation of numerical prediction of blood flow in arterial bypass grafts

In planning operations for patients with cardiovascular disease, vascular surgeons rely on their training, past experiences with patients with similar conditions, and diagnostic imaging data. However, variability in patient anatomy and physiology makes it difficult to quantitatively predict the surgical outcome for a specific patient a priori. We have developed a simulation-based medical planning system that utilizes three-dimensional finite-element analysis methods and patient-specific anatomic and physiologic information to predict changes in blood flow resulting from surgical bypass procedures. In order to apply these computational methods, they must be validated against direct experimental measurements. In this study, we compared in vivo flow measurements obtained using magnetic resonance imaging techniques to calculated flow values predicted using our analysis methods in thoraco–thoraco aortic bypass procedures in eight pigs. Predicted average flow rates and flow rate waveforms were compared for two locations. The predicted and measured waveforms had similar shapes and amplitudes, while flow distribution predictions were within 10.6% of the experimental data. The average absolute difference in the bypass-to-inlet blood flow ratio was 5.4±2.8%. For the aorta-to-inlet blood flow ratio, the average absolute difference was 6.0±3.3%. © 2002 Biomedical Engineering Society. PAC2002: 8761Lh, 8719Uv     

Immune response in symptomatic and asymptomatic neurocysticercosis

Innate immune system is crucial in the pathogenesis of neurocysticercosis (NCC) and helminth glycans can induce anti-inflammatory milieu via toll-like receptor 4 (TLR4) dependent mechanisms. The association of TLR4 and cytokines is yet to be explored in NCC. Therefore, the present study detected the serum levels of cytokines and soluble intercellular adhesion molecule (sICAM)-1 in asymptomatic and symptomatic NCC and their association with TLR4 expression. Sixty eight patients with NCC (asymptomatic, 36 and symptomatic, 32), and age and gender matched 37 healthy controls were enrolled to determine the levels of different pro- and anti-inflammatory cytokines, sICAM-1 in the serum by ELISA and expression of TLR4 in peripheral blood mononuclear cells (PBMCs) by flow cytometry. In asymptomatic NCC cases, the levels of IL-10 and IL-4 were significantly elevated compared to healthy controls and symptomatic NCC patients whereas the levels of IFN-γ, TNF-α, IL-17, IL-23 and sICAM-1 were higher in symptomatic NCC patients compared to healthy controls and asymptomatic NCC individuals. Frequency of TLR4 expressing PBMCs and CD14 positive cells were significantly higher in both groups of NCC. Although the number of TLR4 expressing cells was almost similar in both asymptomatic and symptomatic groups, the median fluorescence intensity was significantly higher in symptomatic group indicating that higher levels of TLR4 expression in symptomatic patients correlated with enhanced pro-inflammatory cytokine production.     

Distribution and molecular analysis of Blastocystis subtypes from gastrointestinal symptomatic and asymptomatic patients in Iran

IntroductionBlastocystis is a common intestinal parasite of human and animal hosts. The parasite has 17 subtypes, and among those at least nine subtypes (ST1-ST9) are found in human hosts.ObjectiveThe aim of the present study was to investigate the presence of different subtypes of Blastocystis spp. among the patients referred to Velayat hospital of Qazvin province, Iran.MethodsOverall, 864 stool samples were examined by using formalin-ethyl acetate concentration method and Trichrome staining. All specimens were cultured in clotted fetal bovine medium. Later, DNA extraction and PCR amplification of 18S ribosomal RNA gene region was conducted and phylogenetic tree constructed.ResultsThe results revealed 7.9% (68/864) of the study population were infected with Blastocystis. Intestinal symptoms were observed in 61% (36/59) of individuals positive for Blastocystis, with abdominal pain in 58% (21/36) of cases which was more frequent than other intestinal signs. No significant relationship was observed among the study variables. By molecular and phylogenetic analysis, three subtypes ST1 (45%), ST2 (30%) and ST3 (23%) of parasite were identified.ConclusionThis study showed ST1 subtype was the predominant subtype among the positive specimens, meanwhile the highest haplotype and nucleotide diversity were clarified in ST3 subtype.     

Comparative immunophenotyping of monocytes from symptomatic and asymptomatic atopic individuals

BACKGROUND: Allergy has at least two components - a genetic predisposition referred to as atopy and the progress from an atopic state to clinically apparent disease. Peripheral blood monocytes are circulating myeloid precursors of antigen-presenting cells. The expression of cell surface proteins on monocytes may therefore witness the disease status and affect the development of allergic disease. METHODS: Monocytes were isolated from atopic individuals with seasonal allergic rhinitis (n = 10), from atopic individuals sensitized to aeroallergens but without any signs of acute disease (n = 11), and from healthy nonatopic donors (n = 21). Detailed comparative phenotypic analysis of CD14(+) and FcepsilonRI(+)CD14(+) monocytes was performed by flow cytometry. RESULTS: CD14(+) monocytes from symptomatic atopic donors showed a significant increase in the cell surface intensity of the integrin adhesion molecule CD11c over monocytes from asymptomatic atopic and nonatopic donors. Asymptomatic atopic individuals showed significantly enhanced expression of FcepsilonRI on the CD14(high)CD16(dim) monocyte subset compared with this subset from symptomatic atopic and nonatopic donors. CONCLUSION: The increase in monocyte surface intensity of the adhesion molecule CD11c may be involved in the manifestation of allergic disease. FcepsilonRI on CD14(high)CD16(dim) monocytes of asymptomatic atopic donors may be of functional importance for the maintenance of clinical unresponsiveness toward allergens.     

In vitro method to differentiate isolates of type III Streptococcus agalactiae from symptomatic and asymptomatic patients

Streptococcus agalactiae (group B streptococci) isolates from infected infants have been demonstrated to have three- to fourfold or higher levels of cell-associated lipoteichoic acid than isolates from asymptomatically colonized infants, suggesting a role for this cell surface polymer in the relative virulence of these organisms. The present study indicates that symptomatic isolates of type III group B streptococci can be readily differentiated from asymptomatic strains by their response to various levels of phosphate in a chemically defined medium (FMC). Both classes of isolates had the same doubling time (TD of 30 to 35 min) in FMC containing 65 mM sodium phosphate. However, levels of phosphate greater than 125 mM distinguished the two classes of strains. Asymptomatic strains pregrown in 65 mM phosphate to the stationary phase rapidly initiated growth at elevated phosphate levels, while symptomatic strains initiated growth only after a prolonged incubation period (greater than 400 min). These results suggest that the physiological growth response of clinical isolates of group B streptococci to phosphate can serve as a diagnostic aid in screening potentially virulent strains in pregnant women and newborn infants.     

Endometrial pathology in postmenopausal tamoxifen treatment: comparison between gynaecologically symptomatic and asymptomatic breast cancer patients.

AIMS: To evaluate whether endometrial pathology is more likely to be diagnosed in gynaecologically symptomatic rather than in gynaecologically asymptomatic postmenopausal breast cancer patients with tamoxifen treatment; and to evaluate the possible influence of various clinical factors on the incidence of endometrial pathology. METHODS: Endometrial histological findings, transvaginal ultrasonographic endometrial thickness, demographic characteristics, health habits, and risk factors for endometrial cancer were compared between 14 gynaecologically symptomatic (group I) and 224 gynaecologically asymptomatic (group II) postmenopausal breast cancer patients with tamoxifen treatment. RESULTS: Overall, 28.6% of the study population had endometrial pathology. The incidence of overall positive endometrial histological findings was significantly higher in group I than in group II (92.9% v 24.6%, p < 0.0001). Atrophic endometrium was more common in group II than in group I (75.3% v 7.1%, p < 0.0001). Most other endometrial pathology was significantly more common in group I than in group II (endometrial hyperplasia, 35.7% v 5.6%, p < 0.0001; endometrial polyps, 35.7% v 13.4%, p < 0.0111; endometrial carcinoma, 21.5% v 0.9%, p < 0.0001). Endometrial pathology appeared considerably later in the gynaecologically asymptomatic patients than in gynaecologically symptomatic patients (p = 0.0002). Vaginal bleeding or spotting occurred exclusively in group I. The incidence of endometrial pathology in the entire study population was consistent with that reported elsewhere, and higher than that reported for healthy postmenopausal women. CONCLUSIONS: Endometrial pathology is more likely to be diagnosed in gynaecologically symptomatic postmenopausal breast cancer patients with tamoxifen treatment, and after a shorter duration of time, than in gynaecologically asymptomatic patients.     

Eosinophil apoptosis in induced sputum from patients with seasonal allergic rhinitis and with asymptomatic and symptomatic asthma.

BACKGROUND: Eosinophilic inflammation is known to play an important role in the pathogenesis of allergic diseases. Apoptosis, a form of programmed cell death, is characterized by morphologic cell changes and leads to recognition and ingestion by macrophages. Apoptosis could be an important mechanism controlling the resolution of tissue eosinophilia. OBJECTIVE: This study was designed to investigate the presence of apoptotic eosinophils in induced sputum of patients with seasonal allergic rhinitis (SAR), when examined during natural pollen exposure and of patients with perennial asthma of different degrees of severity. METHODS: We recruited 11 patients with SAR to grass pollens, 26 patients with asymptomatic asthma (AA), and 18 patients with symptomatic asthma (SA). The severity of asthma was assessed by clinical scoring. Sputum was induced following a standard method and differential cell count was estimated. Eosinophils showing cell shrinkage and nuclear coalescence were classified as apoptotic. The number of apoptotic eosinophils was expressed as the percentage of total cells in sputum and as the proportion of apoptotic eosinophils relative to normal bilobed eosinophils ("apoptotic ratio"). RESULTS: We found the number of eosinophils in the SA group was significantly greater than that in the SAR and the AA groups (P < .001 and P < .0001 respectively). The number of apoptotic eosinophils in the AA group was significantly lower than that in the SAR group (P < .001) and in the SA group (P < .0001). The apoptotic ratio for eosinophils in the SAR group was significantly greater than in the AA group (P < .05) and in the SA group (P < .05). There was no difference in the apoptotic ratio between the AA and SA groups. CONCLUSIONS: This study confirms that apoptotic eosinophils are detectable in induced sputum of allergic patients. Further, the results of our study suggest that apoptosis could be an important mechanism in the control of acute eosinophilic inflammation in patients with SAR exposed to the sensitizing antigens. It appears that the apoptotic mechanism could be less effective in controlling tissue eosinophilia in asthmatic patients with chronic eosinophilic inflammation.     

Intestinal colonization of symptomatic and asymptomatic schoolchildren with Blastocystis hominis.

A study of single stool specimens was done to determine the prevalence of intestinal parasites among 1,000 primary school children. A questionnaire was completed by each child's parents. Specimens were examined by using wet-mount preparation, formaline-ether concentration, and Sheather's flotation technique. Trichrome and acid-fast stains were done. Blastocystis hominis was observed in 203 (20.3%) of the specimens examined, and 175 specimens contained this organism in the absence of other pathogenic parasites. Older children had fewer B. hominis infections (6 to 7 years old, 50% infection rate; 8 to 9 years, 27.5%; 10 to 12 years, 9.5%). The most common complaints reported by 75 children harboring the parasite were a mild recurrent diarrhea, abdominal pain, nausea, anorexia, and fatigue. Blastocystosis is quite common among schoolchildren. Contaminated drinking water is suspected to be the source of infection.     

PCR fingerprinting of Blastocystis isolated from symptomatic and asymptomatic human hosts

Genomic DNA from 16 Blastocystis hominis isolates comprising of eight asymptomatic isolates (A1–A8) and eight symptomatic isolates (S1–S8) was amplified by arbitrarily primed polymerase chain reaction (AP-PCR) using 38 arbitrary 10-mer primers. Six primers (A10, B5, C20, D1, F6, and F10) generated reproducible DNA fingerprints. AP-PCR amplification revealed similar DNA fingerprints among all symptomatic isolates (S1–S8) with common bands at 850 bp using primer A10, 920 bp using primer B5, and 1.3 kbp using primer D1. Isolates A1, A3, A4, A5, A6, and A7 showed similar DNA banding patterns and all asymptomatic isolates (A1–A8) shared a major band at 1 kbp using primer B5. Isolates A2 and A8 showed distinct DNA banding patterns that differed from the remainder of the isolates. The results of the phylogenetic analyses showed that all symptomatic isolates (S1–S8) formed a clade with >70% similarity among the isolates and which were clearly separate from asymptomatic isolates A1, A3, A4, A5, A6, and A7. Asymptomatic isolates A2 and A8 formed two distinct and separate clades. AP-PCR revealed higher genetic variability within the asymptomatic isolates than within the symptomatic isolates. The present study suggests that AP-PCR can be a valuable method for differentiating between isolates of B. hominis and our results support the hypothesis that our asymptomatic and symptomatic B. hominis isolates may represent two different strains/species with varying pathogenic potential.     

Cell-mediated and humoral adaptive immune responses to SARS-CoV-2 are lower in asymptomatic than symptomatic COVID-19 patients

The characterization of cell-mediated and humoral adaptive immune responses to SARS-CoV-2 is fundamental to understand COVID-19 progression and the development of immunological memory to the virus. In this study, we detected T-cells reactive to SARS-CoV-2 proteins M, S, and N, as well as serum virus-specific IgM, IgA, IgG, in nearly all SARS-CoV-2 infected individuals, but not in healthy donors. Virus-reactive T cells exhibited signs of in vivo activation, as suggested by the surface expression of immune-checkpoint molecules PD1 and TIGIT. Of note, we detected antigen-specific adaptive immune response both in asymptomatic and symptomatic SARS-CoV-2 infected subjects. More importantly, symptomatic patients displayed a significantly higher magnitude of both cell-mediated and humoral adaptive immune response to the virus, as compared to asymptomatic individuals. These findings suggest that an uncontrolled adaptive immune response contribute to the development of the life-threatening inflammatory phase of the disease. Finally, this study might open the way to develop effective vaccination strategies.