The neuropathogenesis of the AIDS dementia complex.
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Biomedical subjects
Publications and source records attributed to M Fiala.
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The so called Mahaim connections form a relatively scarce variant of the preexcitation syndrome. Antidromic atrioventricular reentry tachycardia with wide QRS complex of LBBB morphology represents a typical clinical manifestation of the condition. Nodofascicular and nodoventricular fibres in all the probability do exist, but only rarely. Most of these accessory pathways are located on the firht free wall and conduct only antegradely and decrementally. Majority of these pathways are formed by long bundles inserting in the terminal part of the right bundle branch or in the myocardium near the right ventricular apex. In this setting traditional mapping strategy is of little use and different approaches must be employed. Only minority of these right-sided accessory pathways are short inserting in the ventricular myocardium under the tricuspid annulus. We present two case reports of patients with accessory connections exhibiting the so called Mahaim electrophysiology. In the first case, the pathway was merely an innocent bystander that, however, masked serious low intrahissian conduction disturbance. In the second case, the patient had a long-standing characteristic symptomatology due to the right anterolateral short accessory pathway which was successfully mapped and ablated.
'Restricted' human immunodeficiency virus type (HIV-1) infection of astrocytes is recognized in vivo in some pediatric and adult AIDS brains and in vitro in a small proportion of transfected primary fetal astrocytes. We investigated the extent of HIV-1JR-FL expression in fetal astrocytes and macrophages cultivated alone or together. Peak HIV-1 p24 antigen titres in supernatant fluids of macrophage cultures were increased with monocyte/macrophages from certain donors and were higher when macrophages were cocultivated with astrocytes. Structural HIV-1 gene (gp 41 and pol) products (protein and mRNA) were observed only in macrophages. Ten days after HIV-1JR-FL infection, astrocytes in a monoculture were stained negative or only weakly positive (1-2+) for Nef, whereas in a coculture up to 100% of astrocytes displayed Nef staining (up to 4+) in the cytoplasm. The streptavidine-biotine-peroxidase technique with certain monoclonal antibodies to Nef (Ovod et al, 1992) was specific for infected astrocytes. The intensity of Nef staining was higher in astrocytes cultivated with monocyte/macrophages from certain donors. In the coculture, tumor necrosis factor-alpha (TNF-alpha) was expressed in the astrocyte cytoplasm earlier after coinfection with HIV-1 and cytomegalovirus (CMV) compared to infection with HIV-1 alone. Interleukin-6 (IL-6) was secreted spontaneously and transiently in uninfected cocultures, but in a prolonged fashion following HIV-1 and HIV-1/CMV infections. The interactions between HIV-1- and CMV-infected macrophages and astrocytes lead to upregulation of TNF-alpha and IL-6 and enhancement of productive HIV-1 infection of macrophages and of 'restricted' HIV-1 infection of astrocytes with implications for the pathogenesis of AIDS dementia.
We have studied longitudinally ten patients with AIDS encephalopathy with respect to pathogenetic roles of human immunodeficiency virus (HIV) and cytomegalovirus (CMV). Three patients manifested typical AIDS dementia complex (ADC) (initially without retinitis and with slowly progressive cognitive, motor and behavioral abnormalities which were zidovudine-responsive, and relatively preserved CD4+ T cells), and seven patients presented with AIDS dementia complex complicated by CMV encephalopathy (ACE) (with CMV retinitis, peripheral neuropathy, altered sensorium, and rapidly declining clinical and immunological status). Whereas only HIV antibody was elevated in the spinal fluid of patients with ADC, both virus infections were active in the central nervous system of patients with ACE as shown by HIV p24 antigenemia and antigenrrhachia, elevated HIV and CMV antibody in the spinal fluid, disseminated CMV infection with retinitis, and basilar ventriculoencephalitis with multinucleated cytomegalic cells containing CMV and HIV proteins and CMV DNA. The recognition of ADC and ACE is important, since some patients with ACE may respond to ganciclovir or foscarnet.
To define the histogenesis and cell origin of Kaposi sarcoma (KS), we cultured KS cells without retrovirally conditioned media from three HIV seropositive AIDS patients and then attempted to raise mouse hybrid monoclonal antibodies (Mabs) specific to these AIDS-KS cells. After both in vivo and in vitro immunization trials, all putative Mabs reacted positively to KS cells but also non-specifically with other human (CH5 and OM) and non-human (RSE-1) control endothelial cell lines. To overcome this crossreactivity, we further "absorbed" previously cloned hybrids and pre-hybrid splenocytes by incubating them with the control endothelial cell lines to eliminate splenocytes and/or hybridomas reactive to normal endothelium. Whereas absorption successfully eliminated immunoreactivity to control endothelium, it also excluded reactivity to KS cells. These findings (lack of specific antigenicity and immunoresponsiveness of KS similar to non-KS control endothelium) suggest that AIDS-KS cells are neither antigenically transformed nor neoplastic, but instead represent dedifferentiated or transdifferentiated endothelium which retains immunogenicity of its original endothelial cell prototype.
Serial drug testing (SDT) using programmed electrical stimulation (PES) and a downgraded pacing protocol was performed in 56 patients with sustained ventricular tachycardia (S-VT) of various aetiology. SDT was carried out during oral antiarrhythmic therapy alone or in combination with beta-blockers. The pacing protocol's reduced aggressiveness consisted in prolonging minimal coupling intervals of the third extrastimulus and in milder criteria employed in evaluating the drug in PES and in cases of recurrent S-VT (an S-VT with a heart rate below 150 considered a positive effect of the tested drug). All patients were followed up during the therapy chosen on the basis of SDT for an average 19.7 +/- 19.4 months. SDT led to the identification of an effective therapy in 48 patients (86%, group A). No effective therapy was found for the remaining eight patients (14%, group B). There were no significant differences between both groups in age, sex, representation of individual cardiopathies, the frequency of spontaneous S-VT or ejection fraction. Using Kaplan-Maier's survival curves, the incidence of arrhythmia events (defined as a recurrence of S-VT or sudden death), cardiac death or any death was significantly higher in group B. PES was used to test a total of 202 drugs or their combinations; of this number, S-VT induction failed in 90 (45%). No significant difference in the efficacy of antiarrhythmics was found to be related to whether they had been used alone (44%) or in combination (49%, p > 0.05). Beta-blockers likewise had no effect on the incidence of arrhythmia events during follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)
The nature of Kaposi sarcoma (KS) (vascular malignancy vs. discordant angiogenesis) and lineage of the progenitor cell remain unclear. Therefore, AIDS-KS enzyme isolate cultures were prepared from excised skin lesions. Endothelial marker positivity for Factor VIII related antigen (F8RAg), Ulex europaeus agglutinin (UEA), and angiotensin-converting enzyme (ACE) were determined by fluorescence microscopy (FM) and flow cytometry (FCM). DNA cell-cycle analysis was performed using FCM. KS lesions showed large thick-walled channels (F8RAg and UEA strongly +), narrow vascular slits and thin-walled lakes (F8RAg and UEA weakly +), and non-prominent spindle cells (F8RAg and UEA almost uniformly negative). KS cultures yielded heterogenous populations of spindle, stellate, and flattened endothelial-like cells, displaying positivity for F8RAg (64 +/- 3%; mean +/- SE), UEA (40 +/- 9%), and ACE (81 +/- 9%). When injected subcutaneously in the nude mouse these cells failed to produce tumors. During contact inhibition induced quiescence, KS cultures exhibited a high G2M (18 +/- 3%) compared to non-KS (7 +/- 4%; p < 0.04), evidence of an altered proliferative potential consistent with a transdifferentiated or transformed phenotype.
OBJECTIVE: To assess the effect of recombinant human erythropoietin (r-HuEPO) on anemia in patients with the acquired immunodeficiency syndrome (AIDS) who are receiving zidovudine therapy. DESIGN: Combined analysis of four 12-week, randomized, double-blind, controlled clinical trials. SETTING: Multiple centers in the United States. PATIENTS: Two hundred and ninety-seven anemic (hematocrit < 30%) patients with AIDS who were receiving zidovudine therapy. Of the 297 patients, 255 were evaluable for efficacy, but all patients were included in analysis of safety. INTERVENTION: Patients were randomly assigned to receive either r-HuEPO (100 to 200 U/kg body weight) or placebo, intravenously or subcutaneously, three times per week for up to 12 weeks. MEASUREMENTS: Changes in mean hematocrit, transfusion requirement, and quality of life. RESULTS: Sixty-nine percent of patients had endogenous serum erythropoietin levels less than or equal to 500 IU/L, and 31% had erythropoietin levels greater than 500 IU/L. In patients with low erythropoietin levels (< or equal to 500 IU/l), r-HuEPO therapy decreased the mean number of units of blood transfused per patient when compared with placebo (3.2 units and 5.3 units, respectively; P = 0.003) and increased the mean hematocrit from the baseline level (4.6 percentage points and 0.5 percentage points, respectively; P <0.001). Overall quality of life improved in patients on r-HuEPO therapy (P = 0.13). Patients with erythropoietin levels greater than 500 IU/L showed no benefit from r-HuEPO in any outcome variable. Placebo and r-HuEPO recipients did not differ in the incidence of adverse effects or opportunistic infections. CONCLUSION: Therapy with r-HuEPO can increase the mean hematocrit and decrease the mean transfusion requirement in anemic patients with AIDS who are receiving zidovudine and have endogenous low erythropoietin levels (< or equal to 500 IU/L). Such therapy is of no apparent benefit in patients whose endogenous erythropoietin levels are higher than 500 IU/L.
OBJECTIVE: To determine if a 6-month course of therapy with IMREG-1, a leukocyte-derived immunomodulator, slows disease progression in patients with AIDS-related complex. DESIGN: Randomized, double-blind trial. SETTING: Five academic- and three community-based clinics. PATIENTS: Immunocompromised patients (143) with HIV. INTERVENTIONS: IMREG-1 or placebo every 2 weeks (13 doses). MAIN RESULTS: Twelve of forty-eight patients on placebo and 5 of 95 patients on IMREG-1 experienced adverse events (AIDS-defining opportunistic infection or neoplasm, wasting syndrome, HIV-associated encephalopathy, or peripheral sensory neuropathy). Based on an intention-to-treat analysis, Kaplan-Meier event probabilities were 26% for the placebo group and 6% for the IMREG-1 group (P less than 0.001); based on the Cox proportional hazards model, the relative risk for patients on placebo compared with patients on IMREG-1 was 5.1 (95% CI, 1.8 to 14.8). The frequency of symptoms significantly increased from baseline in patients receiving placebo. The mean decrease in CD4+ cells from baseline was 80 x 10(6) cells/L in the placebo group and 29 x 10(6) cells/L in patients on IMREG-1, with 20% (8) and 38% (32) of patients, respectively, showing a trend toward an increase (P = 0.04). In patients receiving IMREG-1, the size and rate of delayed hypersensitivity responses were larger than in the placebo group. CONCLUSIONS: Patients with AIDS-related complex experienced fewer adverse events and constitutional symptoms after IMREG-1 treatment. The slower loss of CD4+ cells and increased size and rate of delayed hypersensitivity responses most likely reflect the effect of IMREG-1 on the immune system. No toxicity related to IMREG-1 administration was observed.
IMREG-1, an immunomodulatory biological therapeutic, was studied in a placebo-controlled, double-blind, six-month trial in 45 anergic patients with AIDS-related complex (ARC) and 4 with Kaposi's sarcoma, which was followed by compassionate IMREG-1 administration to all subjects. The IMREG-1 group had significantly less AIDS-defining events compared with the placebo group during the randomized trial (6.9 events per 100 person-years vs 43.7 events per 100 person-years, P = 0.018, relative risk 6.33) and the total observation period. Patients receiving IMREG-1 significantly improved their work performance. Nine (41%) of 22 patients in the IMREG-1 group, compared with one (14%) of seven in the placebo group, recovered cutaneous reactivity to tetanus toxoid. At the end of the six-month trial, CD4+ counts were 0.429 x 10(9)/l in the IMREG-1 group and 0.304 x 10(9)/l in the placebo group (P = 0.04). IMREG-1 is a promising therapeutic for HIV-infected patients with symptoms of ARC.
Human immunodeficiency virus (HIV) has been shown to be the initial aetiological agent of the acquired immune deficiency syndrome (AIDS). The recent clinical, epidemiologic, pathological, immunological and molecular data presented in this review point to a multi-step pathogenesis of AIDS involving HIV as an initial cause leading to reactivation of cytomegalovirus (CMV), human herpesvirus-6 (HH-6) and other immunosuppressive organisms. Although the onset of CMV reactivation is not precisely known, it may be related to the transition from AIDS-related complex to AIDS. The molecular interactions between CMV and HIV occur in both directions. Although transcriptional activation of HIV by CMV infection (possibly via induction of NF chi B) is better known, the enhancement of CMV replication by HIV is clinically as important. The interactions between HIV or simian immunodeficiency virus (SIV) and CMV appear to be more specific than between HIV or SIV and other herpes viruses, and are also cell-type-dependent. CMV-induced immune suppression (possibly of variable magnitude with different strains) may be an additional co-factor in AIDS. In a rhesus monkey model, the interaction of SIV with rhesus CMV appears contributory to the reproduction of the full-blown simian AIDS. Patients with AIDS and disseminated CMV infection display the maximum activation of HIV p24 antigenaemia and the greatest deficiency of CD8+ T lymphocytes. Defects in CD4+ and CD8+ T cells, including HIV- and CMV-specific cytotoxic T cells, are crucially important in the progression to terminal AIDS and are related not only to HIV but also to CMV and HH-6 infections of lymphocytes.(ABSTRACT TRUNCATED AT 250 WORDS)
Kaposi sarcoma, a common opportunistic neoplasm complicating AIDS, is thought to arise from the vasculature and possibly from lymphatic endothelium. To evaluate the nature and extent of lymphatic involvement in AIDS-associated Kaposi sarcoma, we used an improved technique of whole-body lymphangioscintigraphy. Six human-immunodeficiency-virus-seropositive men (40-51 years old) with AIDS and extensive Kaposi sarcoma had bilateral foot and/or hand intradermal injection of 0.05 ml of 99mTc-labeled human serum albumin (500 microCi, 18.5 MBq). After sequential whole-body scanning with a digital gamma camera, the findings were interpreted by comparing them with findings from similar studies in 30 other patients without AIDS or Kaposi sarcoma (26 with primary or secondary lymphedema and four with normal extremities). Unlike in normal limbs, where lymphangioscintigraphy displayed early lymphatic truncal and regional nodal filling with radionuclide, in patients with Kaposi sarcoma, lymphangioscintigraphy disclosed a variety of abnormal patterns with some features distinct and others resembling lymphatic dysplasia as seen in primary and secondary lymphedema. These included focal accumulation of tracer within lymphatic channels in the distribution of cutaneous Kaposi lesions; delayed tracer transport with absent, faint, or intense regional lymph nodal uptake; and retarded or impeded lymphatic drainage with tracer intensification in the region of Kaposi sarcoma plaques. The impaired lymphatic drainage and nodal dysfunction seen on scintigrams in patients with AIDS-associated Kaposi sarcoma suggest a close connection between the lymphatic system and this disorder.
A simplified method of in situ hybridization is described for the detection of HIV targets. This standardized method can be applied to sections of formalin-fixed paraffin-embedded tissues, cell blocks, and smears of cultured cells using 3H- or 35S-labeled DNA and 35S-labeled RNA probes. In order to use elevated stringencies in the hybridization and wash steps, tissue sections and cells are covalently bonded to silanated glass slides without their subsequent loss from the slides. Routine hematoxylin and eosin or Romanovsky's stains enable the identification of the cells detected by in situ hybridization. HIV-infected neuroblastoma and lymphoid cell lines, lymph nodes, bone marrow, kidney, as well as brain tissue from patients with acquired immunodeficiency syndrome (AIDS) and AIDS-related complex are used to demonstrate the generality of the procedure. The standardized method described widens the ease and applicability of in situ hybridization in the investigation of pathologic tissues with the use of diverse specimens and probes.
Based on ongoing basic and clinical investigations, further evidence is presented that the AIDS-Kaposi sarcoma (AIDS-KS) complex involves a progressive disturbance of the blood-lymph circulatory loop of fluid, macromolecules, and migrating cells. We first surveyed the spectrum of vascular abnormalities including Kaposi sarcoma (KS) found in the AIDS/ARC population, then non-invasively imaged lymphatic system abnormalities in AIDS-KS by whole body lymphangioscintigraphy, and finally examined the biologic behavior of AIDS-KS cells in long-term tissue culture. These observations are viewed in terms of the lymphatic and blood vascular route of entry and transport of free and cell-associated virus and other opportunistic pathogens as well as poorly understood host endothelial-immune system interactions.
A T4+ lymphoblastoid cell line (CR-10) persistently infected with the human immunodeficiency virus (HIV) and designated CR-10/NIT was superinfected with cytomegalovirus (CMV) isolated from peripheral blood mononuclear cells of a patient with AIDS. A productive CMV cycle in the CR-10/NIT lymphoblasts was demonstrated by fluorescent antibody staining (IF) using a monoclonal antibody (MAb) to the 150-kDa major capsid protein, by infectivity assays and by electron microscopy (EM). Two-color IF analysis showed that a small percentage of the CR-10/NIT cells were producing both CMV and HIV at any one time. EM studies revealed that all doubly infected cells were lysed whereas most cells infected only with HIV appeared intact. Cell lysis appeared 24 hr after superinfection of the CR-10/NIT cells with CMV and progressed to complete destruction of the cell culture between days 9 and 10. Our results suggest that CMV may convert a mildly cytopathic HIV infection of T lymphoblasts into a highly lytic process.
The authors revealed very often open bite in preschool children with interdental sigmatism and vice versa. They investigated the effect of interdental sigmatism on the persistence of open bite. According to the authors findings open bite persists in 3-5 year-old children with open bite and interdental sigmatism after a 10-to-22 month follow-up significantly more often than in children of similar age with open bite but without interdental sigmatism. Interdental sigmatism is associated with already existing open bite. It is possible that at the time of their development open bite and interdental sigmatism have no causal relationship and the two defects associate accidentally. Only during subsequent development open bite persists more frequently in those children who suffer at the same time from interdental sigmatism, while in children without interdental sigmatism the open bite improves more often.
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Two patients with mononucleosis, one due to cytomegalovirus (CMV), and the other due to Epstein-Barr virus (EBV), presenting with high fever, malaise and hepatitis, had granulomas in the bone marrow but not in the liver. In patients who have unexplained fever, bone marrow granulomas may be a clue to CMV or EBV infection and need not initially raise the fear of prognostically more severe illness.