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Biomedical subjects

D Nadal

Publications and source records attributed to D Nadal.

At least 91 records · Page 5Linked to original sources

Intracellular location of Bartonella henselae cocultivated with Vero cells and used for an indirect fluorescent-antibody test.

Bartonella henselae, the major causative agent of cat scratch disease, was cocultivated with Vero cells on chamber slides and visualized by indirect immunofluorescence by using a patient serum containing specific antibodies. Confocal microscopy localized the granular B. henselae-specific fluorescence mainly around the nuclei of Vero cells. By transmission electron microscopy, these granules were identified as clusters of multiple intracellular organisms. Fixed slides with the monolayers of Vero cells with intracellular B. henselae were used for an indirect fluorescent-antibody test to investigate the seroprevalence of specific immunoglobulin G in 100 serum samples from blood donors. Seventy-four serum samples were negative; 19, 3, and 4 were positive at dilutions of 1:64, 1:128, and 1:256, respectively. In our population, a serum titer of 1:256 or greater should stimulate further investigations. Moreover, elucidation of the mechanism by which B. henselae enters the cells may help to understand the pathogenesis of cat scratch disease.

Animals↗

[The status of infection with Toxoplasma gondii in the Swiss population: contribution of a seroepidemiologic study from the Zurich canton].

To obtain information on the seroprevalence of specific antibodies to Toxoplasma gondii at the level of the general population, a study was performed using 4300 serum samples: 3500 samples collected at the blood donor center of Zürich (individuals between 18 and > 65 years old), 500 serum samples from children referred to the University Children's Hospital of Zürich (between 1 month and 17 years old) and 300 maternal sera, collected at delivery (from a mother-child sera collection of the University Children's Hospital of Zürich). Samples were systematically collected by age- (5 years) and sex-groups (sex ratio 1:1), until the desired number was obtained. The crude seroprevalence of specific IgG anti-T. gondii was 52.4% (confidence interval at 95% [p < 0.05]: 50.9-53.9). There were no significant differences between males and females. The seroprevalence of the group of women of childbearing age (between 20 and 40) was 40%. The comparison of this value with the results obtained from 300 maternal sera from the mother-child collection revealed no significant difference between the two groups. On the basis of these results and assuming that the information obtained at the level of the general population in the region of Zürich is representative of Switzerland, it was possible to calculate the required sample size to initiate a national study on seroprevalence of the infection with T. gondii among women at time of delivery.

Adolescent↗

[Congenital toxoplasmosis: pediatric approach. Consensus report of the Swiss infectious disease pediatricians].

The first part of this paper reviews: (1) the spectrum of clinical features of congenital toxoplasmosis; (2) the natural course of fetal infection; (3) the influence of antitoxoplasma therapy on the course of the disease; (4) methods for diagnosing the toxoplasma infection and assessing the severity of the disease; (5) currently used antitoxoplasma drugs and different therapeutic regimens. The second part suggests a practical approach to the problem of congenital toxoplasma infection, including diagnostic work-up, drug therapy, and follow-up. This practical approach is modulated according to the clinical syndrome in the infant and diagnostic and therapeutic considerations in the mother.

Coccidiostats↗

Non-Hodgkin's lymphoma in four children infected with the human immunodeficiency virus. Association with Epstein-Barr Virus and treatment.

BACKGROUND: Reports on lymphoid malignancy and its treatment in children infected with human immunodeficiency virus (HIV) are limited. METHODS: Antibodies to Epstein-Barr virus (EBV) were detected by indirect immunofluorescence. DNA was extracted from peripheral blood lymphocytes or biopsy specimens. Polymerase chain reaction was run using primers for EBV. Reaction products underwent Southern blot analysis to confirm EBV specificity. Tumor clonality was assessed by immunohistochemistry and by Southern blot analysis of immunoglobulin heavy-chain and T-cell receptor beta-gene rearrangement. RESULTS: Within 1 year, non-Hodgkin's lymphoma (NHL) was diagnosed in four children infected with HIV. All four were EBV-seropositive and had detectable EBV DNA in peripheral blood lymphocytes. The EBV-linked disorders lymphoid interstitial pneumonia and recurrent parotid enlargement preceded NHL in three and two of the children, respectively. In all four patients, NHL involved at one time the central nervous system (CNS). All three tested NHL tissues were positive for EBV DNA: A 12-week course of chemotherapy given to two children resulted in rapid tumor regression. One of these children experienced meningeal relapse and died 16 months after diagnosis. The other child, who in addition received local irradiation of the affected eye and who underwent surgical removal of the involved ovaries, has been in continuous remission for 20 months. CONCLUSIONS: EBV-associated NHL may be seen more frequently in pediatric patients with HIV. Treatment protocols taking into account NHL propensity for the CNS in this age group need to be developed.

Abdominal Neoplasms↗

Management of petrous bone fractures in children: analysis of 127 cases.

Petrous bone fractures (PBF) in children are relatively frequent. They are mostly diagnosed after collisions and falls. The complications typically associated with PBF were different types of hearing disorders in 69.1% of the patients who had audiometry, liquorrhea in 16.5%, palsy of cranial nerves in 10.8% (facial nerve palsy in 9.4%), bacterial meningitis, stenosis of the external ear canal, and posttraumatic cholesteatoma in 0.7% of the fractures each. Most complications were transient; 8.6% of the patients underwent surgery because of PBF-related complications and 9.4% suffered from severe, irreversible sequelae. Management of PBF in children requires an interdisciplinary approach between pediatric surgeons and pediatric ear, nose, and throat (ENT) specialists. It basically includes daily examination for cranial nerve palsy, liquorrhea, and meningitis during hospitalization as well as routine audiometric examination and antibiotic prophylaxis. Routine vaccination against Streptococcus pneumoniae as a new standard procedure and subtotal petrosectomy after transverse fracture as a new surgical modality are strongly recommended in order to lower the incidence of posttraumatic meningitis. Severe complications such as persistent hearing loss, persistent liquorrhea, cranial nerve palsy, and posttraumatic meningitis require aggressive diagnostic and therapeutic measures in order to minimize further morbidity and irreversible deficits.

Adolescent↗

Disseminated cat-scratch disease: detection of Rochalimaea henselae in affected tissue.

An immunocompetent 9-year-old boy with disseminated cat scratch disease involving spleen, cervical and abdominal lymph nodes, skull, and one clavicle is reported. Antibodies to Rochalimaea quintana and R. henselae were detected, at increasing, then decreasing concentration. DNA extracted from the biopsied skull lesion was amplified by polymerase chain reaction and hybridized with species-specific oligonucleotides proving the presence of R. henselae in affected tissue. Our findings suggest that R. henselae plays a pathogenic role in cat-scratch disease.

Antibodies, Bacterial↗

Deletions within the LMP1 oncogene of Epstein-Barr virus are clustered in Hodgkin's disease and identical to those observed in nasopharyngeal carcinoma.

This study of 52 European patients with Hodgkin's disease (HD) expressing the latent membrane protein 1 (LMP1) oncogene within diagnostic Hodgkin and Reed-Sternberg (HRS) cells was performed to detect LMP1 isolates carrying deletions and to characterize them at a molecular and histologic level. Deletions were identified in 5 cases, clustered near the 3' end of the LMP1 gene, and histologically associated with numerous HRS cells. DNA sequencing showed homology with the deletions seen in the Asian nasopharyngeal carcinoma (NPC) isolates CAO and 1510. Our findings suggest that partial deletions of the LMP1 oncogene, associated with aggressive behavior in NPC CAO and NPC 1510, occur at a particular localization and confer a proliferative phenotype to lymphoid cells in HD.

Adult↗

Listeria meningitis: identification of a cerebrospinal fluid inhibitor of macrophage listericidal function as interleukin 10.

The killing of bacteria gaining access to the central nervous system is insufficient and requires bactericidal antibiotics for treatment. The inefficient host response in cerebrospinal fluid (CSF) is thought to be due to impaired phagocytosis in CSF, and low local concentration of antibody and complement. In addition, the CSF may contain inhibitors, disabling phagocytes to eliminate bacteria. We have assessed the bactericidal activity of macrophages in the presence of CSF from mice infected intracerebrally with Listeria monocytogenes (LM). Pretreatment of J774A.1 macrophages with interferon gamma (IFN-gamma) resulted in high levels of nitric oxide-dependent intracellular killing of LM. CSF taken from mice 24 h after infection (CSF-LM 24) contained IFN-gamma and induced killing of LM by macrophages. However, pulsing J774A.1 cells with IFN-gamma in the presence of CSF obtained from mice at later time points (48 h) rendered macrophages partly permissive for intracellular Listeria growth. The inhibitor detected in CSF-LM 48 was identified as IL-10 since: (a) IL-10 dose dependently impaired the listericidal activity of IFN-gamma-activated macrophages; (b) anti-IL-10 antibodies abrogated the bacterial growth permissive effect of CSF-LM 48; and (c) IL-10 was detected in CSF-LM 48 but not in CSF-LM 24 or CSF of mock-injected animals (CSF-Co). Likewise, IL-10 was found in the CSF of 95% of patients with bacterial meningitis.

Animals↗

Invasive infection with Mycobacterium genavense in three children with the acquired immunodeficiency syndrome.

Three children with human immunodeficiency virus infection and invasive infection with Mycobacterium genavense are reported. Fever spikes, abdominal cramps and distension, diarrhea or ileus, and anemia were the predominant symptoms in the severely immunodeficient patients (CD4 lymphocytes < 0.04 x 10(9)/l). Numerous acid-fast bacilli were readily detectable by microscopy in stool samples and in lymph node biopsies, but cultures for mycobacteria remained negative. Mycobacterium genavense should be sought when invasive non-tuberculous mycobacteriosis is suspected and mycobacterial cultures from blood or other sites show limited growth. Multiple-drug regimens including amikacin, ethambutol, rifampin, and clarithromycin may be of benefit in controlling the infection, as observed in two patients.

AIDS-Related Opportunistic Infections↗

T cell activation and cytokine release in streptococcal toxic shock-like syndrome.

A 5-year-old girl with streptococcal toxic shock-like syndrome during varicella infection had high levels of tumor necrosis factor alpha and interleukin-6 but no interleukin-1 or interleukin-2 in the serum. Intravenous administration of gamma-globulin coincided with clinical improvement and with reduction of the levels of tumor necrosis factor alpha and interleukin-6. The data suggest that streptococcal pyrogenic exotoxins trigger synthesis of tumor necrosis factor alpha and interleukin-6 in vivo; intravenously administered gamma-globulin may down-regulate the cytokine response.

Arthritis, Infectious↗

Intestinal coinfection with Enterocytozoon bieneusi and Cryptosporidium in a human immunodeficiency virus-infected child with chronic diarrhea.

The microsporidian Enterocytozoon bieneusi has been recognized as an important cause of chronic diarrhea in severely immunodeficient adults infected with human immunodeficiency virus (HIV). We report the first case of intestinal E. bieneusi infection in a child. The 9-year-old boy with connatal HIV infection presented with failure to thrive, chronic diarrhea, and intermittent abdominal pain. His CD4 lymphocyte count was 0.05 x 10(9)/L and dropped to 0.01 x 10(9)/L. No HIV-associated opportunistic infection other than oral hairy leukoplakia and oral candidiasis had been found before microsporidia were detected. Treatment of microsporidiosis with albendazole was of no benefit. During follow-up, the boy also developed intestinal cryptosporidiosis. Evaluation of chronic diarrhea in severely immunodeficient HIV-infected children should include examination for intestinal microsporidia. We recommend the use of a new coprodiagnostic technique that allows detection of microsporidial spores in stool specimens. Furthermore, consideration of dual or even multiple parasitic infections in the differential diagnosis of chronic diarrhea may have both important clinical and epidemiological implications.

AIDS-Related Opportunistic Infections↗

Distribution characteristics of immunoglobulin-secreting cells in adenoids. Relationship to age and disease.

Forty-four adenoids and 52 palatine tonsils from 71 children and adolescents (age 3-21 years) undergoing surgery because of adenoidal hypertrophy or recurrent tonsillitis were examined for the presence of immunoglobulin-secreting cells (ISC) employing an enzyme-linked immunospot assay (ELISPOT). ISC constituted less than 2% of the mononuclear cell population. Adenoids contained IgG, IgA, and IgM ISC in significantly lower numbers than palatine tonsils. The predominant isotype of the ISC was IgG, in adenoids accounting for 62% of the ISC and in palatine tonsils for 73%. The relative numbers for IgA and IgM ISC were similar. A significant correlation existed between autologous adenoids and palatine tonsils for the numbers of IgA and IgM ISC, but not for the numbers of IgG cells. These observations suggest that, adenoid and palatine tonsils display similar immunoglobulin distribution patterns within a single individual. However, individuals with hypertrophied adenoids exhibited a numeric decrease in IgG ISC with increasing age (P less than 0.01). Both lymphoid tissues may be involved in mucosal immune defense.

Adenoids↗

Role of Epstein-Barr virus and interleukin 6 in the development of lymphomas of human origin in SCID mice engrafted with human tonsillar mononuclear cells.

Mice with severe combined immunodeficiency were inoculated intraperitoneally with 50 x 10(6) human tonsillar mononuclear cells (hu-TMCs) from Epstein-Barr virus (EBV) antibody seropositive or seronegative human subjects. Between 5 and 11 weeks later, 29.4% (10/34) of mice injected with hu-TMCs from EBV seropositive donors, but none of 34 animals receiving hu-TMCs from EBV seronegative donors, developed intraabdominal and/or intrathoracic tumours (P, 0.002). By means of in situ hybridization using alpha satellite DNA from human chromosome 17, all tumours produced after cell transfer from EBV seropositive donors were identified to be of human origin. Histologically the tumours resembled large cell lymphomas; the EBV genome was detected by in situ hybridization and EBV nuclear antigen by immunofluorescence in these tumours. The tumours were poly- or oligoclonal, and stained for human IgG and IgM, and less frequently IgA and IgD. Serum levels of human immunoglobulin in animals developing human tumours were significantly higher than in reconstituted mice without tumours and the sera exhibited polyoligo- or monoclonality in immunoelectrophoresis. Human interleukin 6 was detected in the serum of six of 10 animals with human lymphomas, but not in any animals without human lymphoma.

Adolescent↗