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At least 955 records · Page 53Linked to original sources
PubMed1994

Hyper-IgM immunodeficiency with disseminated cryptococcosis.

We describe two siblings with X-linked hyper-IgM immunodeficiency. One patient developed disseminated cryptococcosis. Co-culture of this patient's T cells with normal B cells suppressed IgG and IgA production. The CD40 ligand gene of one patient was examined and contained a nonsense mutation at nucleotide 475. CD40 ligand is a membrane protein which is expressed on activated T cells and induces B-cell proliferation. These results suggest that there is a defect in T- and B-cell interactions in this immunodeficiency syndrome. It is also possible that patients with this syndrome are predisposed to cryptococcal infections.

Antigens, CD↗
PubMed1999

Selection of hepatitis B surface "escape" mutants during passive immune prophylaxis following liver transplantation: potential impact of genetic changes on polymerase protein function.

CASE REPORT: A patient is described who developed hepatitis B virus (HBV) reinfection five months following liver transplantation. Failure of hepatitis B immunoglobulin prophylaxis was associated with the emergence of mutations. HBV gene sequencing identified nucleotide substitutions associated with amino acid changes, one within the major hydrophilic region (MHR) of the HBV surface antigen at amino acid position 144 and one outside the MHR. Because of the overlapping reading frames of surface and polymerase genes, the latter surface antigen change was associated with an amino acid change in the polymerase protein. The patient developed significant allograft hepatitis and was treated with lamivudine (3TC) 100 mg daily. Rapid decline of serum HBV DNA was observed with loss of HBV e antigen and HBV surface antigen from serum. There was normalisation of liver biochemistry, and liver immunohistochemistry showed a reduction in HBV core and disappearance of HBs antigen staining. CONCLUSION: Surface antigen encoding gene mutations associated with HBIg escape may be associated with alteration of the polymerase protein. The polymerase changes may affect sensitivity to antiviral treatment. Selection pressure on one HBV reading frame (for example, HBIg pressure on HBsAg, or nucleoside analogue pressure on polymerase protein) may alter the gene product of the overlapping frame. Such interactions are relevant to strategies employing passive immune prophylaxis and antiviral treatment.

Aged↗
PubMed2002

Fatal hepatitis B reactivation following discontinuation of nucleoside analogues for chronic hepatitis B.

BACKGROUND: Nucleoside analogues such as lamivudine for chronic hepatitis B have an excellent safety profile while patients are on therapy but reactivation flares occur in 19-50% of patients after stopping therapy, some of whom develop liver decompensation. AIMS: To describe and report three cases who developed fatal hepatitis B reactivation after stopping nucleoside analogue therapy. SUBJECTS AND RESULTS: Three patients are described who developed hepatitis B reactivation and liver decompensation after stopping therapy. One of the three patients was participating in a famciclovir trial and the other two were receiving lamivudine therapy for active hepatitis B infection. All three patients had documented hepatitis B flares, and all had hepatitis B virus DNA detected at that time. All patients developed decompensated liver disease despite one patient having had a prior liver biopsy showing absence of cirrhosis. Reintroduction of lamivudine therapy failed to halt progression of liver decompensation even after hepatitis B virus DNA had been demonstrated to be absent. Sequencing for lamivudine resistant mutants in two cases where serum was available failed to show evidence of mutations associated with lamivudine resistance. CONCLUSION: Hepatitis B virus reactivation, leading to decompensation and death, are possible complications of treatment withdrawal and patients should be monitored closely if therapy is ceased.

2-Aminopurine↗
PubMed1999

Granular-lattice (Avellino) corneal dystrophy.

Granular-lattice (Avellino) corneal dystrophy has rarely been reported in the literature. It consists of a combination of granular and lattice dystrophy. We describe the histopathologic examination of the corneal button of one Japanese patient who had undergone unilateral keratoplasty because of severely decreased vision caused by what had been diagnosed clinically as granular dystrophy. However, on pathologic examination, lesions characteristic of both granular dystrophy and lattice dystrophy were found. We also describe 2 Japanese patients who had a clinical appearance characteristic of both granular and lattice dystrophy. Granular-lattice corneal dystrophy was found in a wider geographic distribution than previously proposed and should not be named after the geographic area.

Adult↗
PubMed1986

Herpesvirus.

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Animals↗
PubMed1987

Activation of latent herpes simplex virus type 2 infection in vitro requires a (E)-5-(2-bromovinyl)-2'-deoxyuridine-sensitive gene function.

Previous studies have shown that herpes simplex virus (HSV) type 2 (HSV-2) can be maintained in a latent state in a limited number of cells by elevating the incubation temperature after treatment of HSV-infected human fetus lung fibroblast cells with metabolic inhibitors. Superinfection with human cytomegalovirus (HCMV) of latently infected cells maintained at the elevated temperature reactivated latent virus. In addition, superinfection with temperature-sensitive mutants indicated that reactivation of latent HSV in vitro did not require the expression of late gene function(s) of the superinfecting virus. We now report the (i) design of an in vitro HSV-2-latency system in which a higher percentage of cells contain a virus genome that can be activated; and (ii) subsequent use of this system to further characterize the virus activation process. Superinfection with a transcription-negative temperature-sensitive mutant of HSV type 1 (HSV-1) did not reactivate HSV-2-replication, suggesting that adsorption and penetration of the superinfecting virus were not sufficient for reactivation of the latent virus. Furthermore, superinfection with HSV-1 in the presence of (E)-5-(2-bromovinyl)-2'-deoxyuridine did not reactivate HSV-2 replication, suggesting that the expression of the immediate-early gene products are not sufficient for HSV-2 reactivation. Collectively, these data suggest that in addition to the expression of immediate-early gene function(s) at least a subset of early HSV-1 gene products are required for reactivation of latent HSV-2 in vitro.

Antiviral Agents↗
PubMed2006

Persistent inhibition of telomerase reprograms adult T-cell leukemia to p53-dependent senescence.

The antiviral thymidine analog azidothymidine (AZT) is used to treat several virus-associated human cancers. However, to date the mechanism of AZT action remains unclear and thus, reasons for treatment failure are unknown. Adult T-cell leukemia/lymphoma (ATL) is an aggressive malignancy of poor prognosis. Here, we report that enduring AZT treatment of T-cell leukemia virus I-infected cells, in vitro and in vivo in ATL patients, results in inhibition of telomerase activity, progressive telomere shortening, and increased p14(ARF) expression. In turn, this elicits stabilization and reactivation of the tumor suppressor p53-dependent transcription, increased expression of the cyclin-dependent kinase inhibitor p21(Waf1), and accumulation of p27(kip1), thereby inducing cellular senescence and tumor cell death. While ATL patients carrying a wild-type p53 enter remission following treatment with AZT, those with a mutated p53 did not respond, and patients' disease relapse was associated with the selection of a tumor clone carrying mutated inactive p53.

Cell Line, Tumor↗
PubMed2006

Clinical implications of FLT3 mutations in pediatric AML.

Activating mutations of the FLT3 gene occur because of an internal tandem duplication of the juxta-membrane domain (FLT3/ITD) or point mutation of the activation loop domain (FLT3/ALM). The presence of FLT3 mutations as well as the allelic ratio of FLT3/ITD (ITD-AR, mutant-wild type ratio) may have prognostic significance. FLT3 mutation status of 630 children with de novo acute myeloid leukemia (AML) treated on CCG-2941 and -2961 was determined, and ITD-AR was calculated for patients with FLT3/ITD. Clinical characteristics and outcomes for patients with FLT3/ALM and FLT3/ITD at varying ITD-ARs was determined and compared with those without FLT3 mutations (FLT3/WT). FLT3/ITD and FLT3/ALM were detected in 77 (12%) and 42 (6.7%) of the patients. Progression-free survival (PFS) was similar in patients with FLT3/ALM and FLT3/WT (51% versus 55%, P = .862). In contrast, PFS at 4 years from study entry for patients with FLT3/ITD was inferior to that of patients with FLT3/WT (31% versus 55%, P < .001). PFS decreased with increasing FLT3/ITD-AR (P < .001), and those with ITD-AR greater than 0.4 had a significantly worse PFS than those with lower ITD-AR (16% versus 72%, P = .001) or with FLT3/WT (55%, P < .001). ITD-AR defines the prognostic significance in FLT3/ITD-positive AML, and ITD-AR greater than 0.4 is a significant and independent prognostic factor for relapse in pediatric AML.

Adolescent↗
PubMed2006

Background selection in single genes may explain patterns of codon bias.

Background selection involves the reduction in effective population size caused by the removal of recurrent deleterious mutations from a population. Previous work has examined this process for large genomic regions. Here we focus on the level of a single gene or small group of genes and investigate how the effects of background selection caused by nonsynonymous mutations are influenced by the lengths of coding sequences, the number and length of introns, intergenic distances, neighboring genes, mutation rate, and recombination rate. We generate our predictions from estimates of the distribution of the fitness effects of nonsynonymous mutations, obtained from DNA sequence diversity data in Drosophila. Results for genes in regions with typical frequencies of crossing over in Drosophila melanogaster suggest that background selection may influence the effective population sizes of different regions of the same gene, consistent with observed differences in codon usage bias along genes. It may also help to cause the observed effects of gene length and introns on codon usage. Gene conversion plays a crucial role in determining the sizes of these effects. The model overpredicts the effects of background selection with large groups of nonrecombining genes, because it ignores Hill-Robertson interference among the mutations involved.

Animals↗
PubMed2005

Monilethrix: improvement with acitretin.

Monilethrix is a rare hereditary disorder that affects the hair and is characterized by shaft anomaly. There is no known treatment that successfully cures the condition. In this report we present a case of monilethrix in a 7-year-old girl treated with oral acitretin. A very good clinical and cosmetic result was obtained while treatment was continued. However, clinical symptoms recurred after discontinuation of acitretin therapy.

Acitretin↗
PubMed2004

Fatal liver failure due to reactivation of lamivudine-resistant HBV mutant.

We report a case of fatal liver failure due to reactivation of lamivudine-resistant HBV. A 53-year-old man was followed since 1998 for HBV-related chronic hepatitis. Serum HBV-DNA was 150 MEq/mL (branched DNA signal amplification assay) and ALT levels fluctuated between 50-200 IU/L with no clinical signs of liver cirrhosis. Lamivudine (100 mg/d) was started in May 2001 and serum HBV-DNA subsequently decreased below undetectable levels. In May 2002, serum HBV-DNA had increased to 410 MEq/mL, along with ALT flare (226 IU/L). The YMDD motif in the DNA polymerase gene had been replaced by YIDD. Lamivudine was continued and ALT spontaneously decreased to the former levels. On Oct 3 the patient presenting with general fatigue, nausea and jaundice was admitted to our hospital. The laboratory data revealed HBV reactivation and liver failure (ALT: 1828 IU/L, total bilirubin: 10 mg/dL, and prothrombin INR: 3.24). For religious reasons, the patient and his family refused blood transfusion, plasma exchange and liver transplantation. The patient died 10 d after admission. The autopsy revealed remarkable liver atrophy.

Drug Resistance, Viral↗
PubMedDate not supplied

Management of hepatitis B after renal transplantation: an update.

Hepatitis B Virus (HBV) infection remains an important cause of liver disease in renal transplant (RT) recipients and the outcome of HBV infected RT recipients is less favorable than that of noninfected RT recipients. The concern about graft loss induced by interferon (IFN) therapy precludes its use; lamivudine, a second-generation analog, has been recently approved for the treatment of hepatitis B and promises to be highly effective in this setting. Several uncontrolled trials have reported a high rate of biochemical (ranging between 80% and 100%) and virological (ranging between 67% and 100%) response in RT recipients, comparable to immunocompetent patients. Lamivudine has an excellent safety profile in RT recipients. However, the emergence of viral mutations leading to resistance has been reported during lamivudine therapy in RT recipients. In addition, numerous issues remain to be clarified about lamivudine use after RT including the management of viral resistance, the role of HBV genotypes in the response to lamivudine, and the duration of therapy and response. The combination of newer nucleoside analogues with lamivudine, analogous to HIV, may further improve the efficacy of antiviral therapy against HBV after RT.

Antiviral Agents↗