Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Recurrent variant”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 163 records · Page 9Linked to original sources
PubMedDate not supplied

[Development of gentamicin-resistant Small Colony Variants of S. aureus after implantation of gentamicin chains in osteomyelitis as a possible cause of recurrence].

AIM: Recently, S. aureus small colony variants (SCVs) were reported to persist within cultured endothelial cells and to cause persistent and antibiotic resistant infections in humans. Because gentamicin can very reproducably select for electron transport deficient SCVs as shown in earlier in vitro experiments, we searched for SCVs in a patient with chronic osteomyelitis, who received gentamicin beads. METHOD: Special culture and identification procedures for determination of SCVs were used, including testing of the S. aureus specific nuc gene, pulsed field gel electrophoresis (PFGE) as a typing method and characterization of the auxotrophism of the SCVs. RESULTS: In a case of a 34-year-old patient with chronic osteomyelitis who had previously been treated with gentamicin beads, menadione auxotrophic S. aureus SCVs as well as wild type S. aureus were recovered in multiple bone specimen. All different colony types isolated from simultaneous or from sequential specimen were shown to be clonal by PFGE. CONCLUSION: Recovery of S. aureus SCVs from a patient treated with gentamicin beads suggests that the slow release of gentamicin into the local environment may be an efficient way to select for and/or induce SCVs. These data should alert physicians to also consider SCVs when a treatment failure occurs in a patient that has received gentamicin beads.

Adult↗
PubMedDate not supplied

Epstein-Barr virus (herpesvirus 4) types A, B and herpesvirus-6 variants A and B in patients presenting with recurrent upper respiratory inflammation, persistent paravertebral thoraco-lumbar muscle spasm and fatigue by polymerase chain reaction (PCR).

DNA from Epstein-Barr virus (EBV) Types A, B and Herpesvirus-6 (HHV-6) Variants A and B was detected by the Polymerase chain reaction (PCR) in the saliva of 51 non-immunocompromised donor patients and in the blood of seventy non-immunocompromised donor patients with specific signs and symptoms. The minimum selection criteria for each patient included acute or recurrent upper respiratory infection, unilateral thoracolumbar muscle spasm and fatigue. PCR DNA detection in the saliva of selected donors revealed 80% of the donors had either Type A or B EBV (41 of 51), 34.1% Type B EBV only (14 of 41), 9% Type A only (4 of 41), and 56.1% Type A and B EBV (23 of 41). HHV-6 DNA was detected in 45.0% (23 of 51). PCR for EBV in blood of selected donors revealed 68.5% Type A or B EBV (48 of 70), 0% type B EBV alone, 64.8% Type A EBV only (31 of 48) and 35.4% both Type A and B EBV (17 of 48). HHV-6 was detected in 96.4% (64 of 70). The association of Type B EBV in the pathogenesis of these patients is explored based on the PCR quantitation of B type EBV DNA present in the samples.

Antibodies, Viral↗
PubMed1998

Two distinct kerato-epithelin mutations in Reis-Bücklers corneal dystrophy.

PURPOSE: Two patients were diagnosed with Reis-Bücklers corneal dystrophy (RBCD), although the pattern and severity of corneal opacification differed. To see whether there was a genetic basis for these phenotypic variations, we analyzed beta ig-h3, the gene that codes for kerato-epithelin and that contains a mutation (Arg555Gln) that causes RBCD. METHODS: A 30-year-old man with honeycomb-shaped subepithelial opacities in his central cornea and a 25-year-old man with progressive subepithelial geographic opacities were both considered to have RBCD. We isolated genomic DNA from leukocytes of the two patients and their family members and screened for an Arg555Gln kerato-epithelin mutation. Then we analyzed all exons of the gene using the single-strand conformation polymorphism (SSCP) technique to search for any other kerato-epithelin mutations. RESULTS: The patient with honeycomb-shaped opacities had an Arg555Gln kerato-epithelin mutation that caused his RBCD, whereas the patient with geographic opacities did not; instead, he had a new kerato-epithelin mutation (Arg124Leu), which cosegregated with his family members. CONCLUSIONS: The variant of RBCD characterized by honeycomb-shaped opacities is caused by an Arg555Gln kerato-epithelin mutation. On the other hand, a new kerato-epithelin mutation, Arg124Leu, was found to cause the RBCD variant characterized by recurrent epithelial erosions and progressive geographic subepithelial opacification. Codon 124 is a hot spot for kerato-epithelin mutations, where the mutations responsible for three autosomal dominant corneal dystrophies--lattice type I (Arg124Cys), Avellino (Arg124His), and the variant of RBCD with geographic rather than honeycomb opacities (Arg124Leu)--are located.

Adult↗
PubMed1992

Long-term study of recurrent vasospastic angina using coronary angiograms during ergonovine provocation tests.

Chronologic changes of coronary spasm were examined by repeated ergonovine provocation tests during angiography. A total of 322 patients who had variant angina without severe atherosclerosis demonstrated a positive response to the first test. Ninety of these patients had recurrent variant anginal symptoms after an angina-free period of 38 +/- 12 months (mean +/- SD). Of these 90 patients, 76 (84%) had symptoms or electrocardiographic (ECG) findings similar to those of the first test. The initial 9 of these 76 patients underwent a second provocation test and showed coronary responses analogous to those on the first test. Of the 90 patients, 14 (16%) had different symptoms or ECG findings from those elicited at the first episode. All 14 patients again had a positive response to a second ergonovine test and the following angiographic changes were observed in the three major vessels between the two tests. Of the 21 vessels that had spasm on the first test, eight vessels (19%) did not have spasm on the second test. Of the 21 vessels that did not demonstrate spasm on the first test, 10 (24%) demonstrated spasm on the second test. In the present study it is concluded that the majority of patients with recurrent angina seemed to have consistency in the location of coronary spasm, while in some patients the fluctuation of coronary spasm was confirmed by two ergonovine provocation tests.

Adult↗
PubMed2001

Recurrent subarachnoid hemorrhage associated with a new transthyretin variant (Gly53Glu).

CNS involvement is rare in systemic amyloidoses due to transthyretin (TTR) mutation and manifests as a combination of dementia, seizures, and myelopathy. The authors report two French siblings who experienced recurrent subarachnoid hemorrhages as the main clinical feature. Brain specimens showed that the leptomeningeal vessels walls were thickened by amyloid deposits, and sequencing of the TTR exons showed a heterozygous single base-pair transition from G to A (codon 53), resulting in a glycine for glutamic acid substitution (G53E).

Adult↗
PubMed2005

Crohn's disease patients carrying Nod2/CARD15 gene variants have an increased and early need for first surgery due to stricturing disease and higher rate of surgical recurrence.

OBJECTIVE: To study the predictive value of Nod2/CARD15 gene variants along with disease phenotypic characteristics for requirement of initial surgery and for surgical recurrence in Crohn's disease (CD). SUMMARY BACKGROUND DATA: Nod2/CARD15 gene variants play an important role in the susceptibility to CD. Studies of genotype-phenotype relationship suggest that these variants are associated with development of intestinal strictures. Preliminary reports analyzing the association between these variants and need for surgery have produced inconsistent results. METHODS: A total of 170 CD patients were included prospectively in the study and followed up regularly for a mean of 7.4 +/- 6.1 years. Clinical characteristics of CD, time and indication for surgery, and recurrence were registered. Nod2/CARD15 gene variants were determined by DNA sequencing analysis. RESULTS: Surgery for stricturing disease was significantly more frequent in patients with Nod2/CARD15 variants in the univariate analysis (odds ratio [OR], 3.63; 95% confidence interval [CI], 1.42-9.27), and it was required at an earlier time (P = 0.004). Only Nod2/CARD15 variants (OR, 3.58; 95% CI, 1.21-10.5) and stricturing phenotype at diagnosis of CD (OR, 9.34; 95% CI, 2.56-33.3) were independent predictive factors of initial surgery for stricturing lesions in the multivariate analysis. Among 70 patients that required surgery, postoperative recurrence was also more frequent in patients with Nod2/CARD15 variants in the univariate and multivariate analysis (OR, 3.29; 95% CI, 1.13-9.56), and reoperation was needed at an earlier time (P = 0.03). CONCLUSION: Nod2/CARD15 variants are associated with early initial surgery due to stenosis and with surgical recurrence in Crohn's disease. Patients with these variants could benefit from preventive and/or early therapeutic strategies.

Adult↗
PubMed1991

Prenatal diagnosis of recurrent Larsen syndrome: further definition of a lethal variant.

Larsen syndrome is characterized by multiple congenital joint dislocations and flattened facies. Some cases have been familial, with both autosomal dominant and recessive patterns of inheritance. Reports of a form of Larsen syndrome, lethal in the neonatal period, are reviewed. We present a family in which recurrence of the syndrome was diagnosed prenatally, but a lethal outcome again resulted despite preparation for anticipated perinatal complications. Because of the wide clinical variation and the lack of a known metabolic defect, delineation between the various forms of Larsen syndrome is difficult. While the lethal variant appears to be a combination of the Larsen phenotype and pulmonary hypoplasia, other features noted in the lethal cases, such as abnormal palmar creases and laryngotracheomalacia, are also seen in patients with Larsen syndrome who survive.

Facial Bones↗
PubMed2004

The 894 G > T variant of endothelial nitric oxide synthase (eNOS) increases the risk of recurrent venous thrombosis through interaction with elevated homocysteine levels.

BACKGROUND: Venous thrombosis is a multicausal disease involving both genetic as well as acquired risk factors. Hyperhomocysteinemia is associated with a 2-fold increased risk of recurrent venous thrombosis (RVT). Recently, the 894 G > T variant of endothelial nitric oxide synthase (eNOS) was postulated to be associated with hyperhomocysteinemia. OBJECTIVES: We hypothesized an interrelation of hyperhomocysteinemia, the eNOS 894 G > T variant and RVT risk. METHODS: The eNOS 894 G > T variant was studied in 170 cases with a history of RVT and 433 controls from the general population. RESULTS: The eNOS 894 TT genotype may increase RVT risk [odds ratio (OR) 1.3 (0.7-2.6)], but no association of the eNOS 894 G > T variant with elevated homocysteine was found in controls. Interestingly, in RVT cases the coexistence of both the 894 TT genotype and elevated tHcy levels (> 90th percentile) was more frequently present than in controls, which led to a substantially increased risk of recurrent venous thrombosis [fasting tHcy OR 5.3 (1.1-24.1), postload tHcy OR 6.5 (1.6-29.5)]. CONCLUSION: The results of the present study demonstrate that the eNOS 894 G > T variation interacts with elevated tHcy levels, leading to an increased risk of recurrent thrombotic events. This interaction points in the direction of S-nitrosation as a mechanism by which homocysteine exerts its detrimental effects on the hemostatic system.

Case-Control Studies↗
PubMed2001

Acquired resistance to the antitumor effect of epidermal growth factor receptor-blocking antibodies in vivo: a role for altered tumor angiogenesis.

Inhibitors of epidermal growth factor receptor (EGFR) signaling are among the novel drugs showing great promise for cancer treatment in the clinic. However, the possibility of acquired resistance to such drugs because of tumor cell genetic instabilities has not yet been explored. Here we report the experimental derivation and properties of such cell variants obtained from recurrent tumor xenografts of the human A431 squamous cell carcinoma, after two consecutive cycles of therapy with one of three different anti-EGFR monoclonal antibodies: mR3, hR3, or C225. Initial response to a 2-week period of treatment was generally total tumor regression and was not significantly different among the three antibody groups. However, tumors often reappeared at the site of inoculation, generally after prolonged latency periods, and most of the tumors became refractory to a second round of therapy. Cell lines established from such resistant tumors retained high EGFR expression, normal sensitivity to anti-EGFR antibody or ligand, and unaltered growth rate when compared with the parental line in vitro. In contrast, the A431 cell variants exhibited an accelerated growth rate and a significantly attenuated response to anti-EGFR antibodies in vivo relative to the parental line. Because of the reported suppressive effect of EGFR inhibitors on vascular endothelial growth factor (VEGF) expression, and the demonstrated role of VEGF in the angiogenesis and growth of A431 tumor xenografts, relative VEGF expression was examined. Five of six resistant variants expressed increased levels of VEGF, which paralleled an increase in both angiogenic potential in vitro and tumor angiogenesis in vivo. In addition, elevated expression of VEGF in variants of A431 cells obtained by gene transfection rendered the cells significantly resistant to anti-EGFR antibodies in vivo. Taken together, the results suggest that, at least in the A431 system, variants displaying acquired resistance to anti-EGFR antibodies can emerge in vivo and can do so, at least in part, by mechanisms involving the selection of tumor cell subpopulations with increased angiogenic potential.

Animals↗
PubMed2005

Transplantation of hepatitis B surface antigen-positive livers into hepatitis B virus-positive recipients and the role of hepatitis delta coinfection.

The scarcity of liver donors requires consideration of grafts from sources not previously used. Allografts from hepatitis B surface antigen (HBsAg)-carriers without a significant liver disease have been proposed for liver transplant recipients with hepatitis B virus (HBV)-related cirrhosis and hepatocellular carcinoma (HCC). Combination prophylaxis schemes against HBV post-liver transplantation (LT) recurrence are currently available; the efficacy of those schemes in HBV-related cirrhosis and HCC must be assessed. This report describes the allocation of HBsAg-positive grafts in three HBsAg-positive recipients, with HBV-related cirrhosis and evolving HCC lesions, two of them with hepatitis Delta virus (HDV) coinfection. Patients were administered anti-hepatitis B immunoglobulins (HBIGs) and lamivudine in order to prevent HBV recurrence. In spite of anti-HBV prophylaxis, HBV infection did persist after LT in all patients (no serum clearance of HBsAg). HBV replication assessed by serum HBV deoxyribonucleic acid (DNA) presence was detected in the first month after LT in the 3 recipients. A prompt HDV reinfection with a clinical and histological pattern of hepatitis was observed in the 2 HBV / HDV coinfected recipients. In 1 of them, an evolving chronic hepatitis required a second LT. The non-HDV-infected patient showed an uneventful follow-up, but the lack of the neutralizing effect of HBIGs and the high risk of escape mutants forced the addition of adefovir-dipivoxil to lamivudine, in order to prevent viral variants and hepatitis recurrence. In conclusion, allografts from HBsAg-positive donors in HBsAg-positive recipients are associated with the persistence of the HBsAg after LT due to the failure of HBIG prophylaxis, even if lamivudine does inhibit virion production. This condition favors HDV replication and HDV hepatitis recurrence in coinfected patients. The allocation of HBsAg-positive grafts in HBsAg-positive recipients could be justified only in recipients without HDV coinfection and a combined prophylaxis with lamivudine and adefovir-dipivoxil is currently the best way to manage escape mutants in these recipients.

Adult↗
PubMed2006

Recurrent CXCR4 sequence variation in a girl with WHIM syndrome.

WHIM (warts-hypogammaglobulinemia-infections-myelokathexis) syndrome is a recently described primary immunodeficiency disorder caused by mutation of the CXCR4 chemokine receptor gene. We report here of a 6.5-yr-old girl with bacterial infections, severe chronic neutropenia, and hypogammaglobulinemia. Sequencing the CXCR4 gene revealed a c.1013C > G sequence variant suggesting WHIM syndrome. Recurrent c.1013C > G sequence variant of the CXCR4 gene resulting in p.S338X truncation mutation of this chemokine receptor protein is first reported here.

Agammaglobulinemia↗
PubMed2006

The small colony variant (SCV) concept -- the role of staphylococcal SCVs in persistent infections.

The recovery of small colony variants (SCVs) from clinical specimens was first described at the beginning of the last century. However, not until the past decade was an association of these variants with chronic, recurrent, and persistent infections such as chronic osteomyelitis and persistent skin and softtissue infection described. Since then, a number of reports and prospective studies have supported a pathogenic role for SCVs in disease. Biochemical and other characteristics of SCVs have suggested a link between electron-transport defective SCV strains and persistent infections, however, the strains examined were genetically undefined SCVs. Therefore, a stable mutant in electron transport was generated by interrupting one of the hemin biosynthetic genes, hemB, in Staphylococcus aureus. This mutant showed characteristics typical of clinical SCVs such as slow growth, decreased pigment formation, low coagulase activity, reduced hemolytic activity, and resistance to aminoglycosides. Furthermore, the mutant was able to persist within cultured endothelial cells due to decreased a-toxin production. It was suggested that the intracellular location of this subpopulation might shield the variants from host defenses and antibiotics, thus providing one explanation for the difficulty in removing SCVs from host tissues. Therefore, a defect in the electron-transport system allows S. aureus SCVs to resist aminoglycosides and persist intracellularly. Because of their fastidious growth characteristics, they are easily missed or misidentified in the clinical laboratory. Therefore, when an infection persists for weeks or months or fails to respond to antimicrobial therapy, clinicians as well as laboratory personnel should consider further efforts to search for this staphylococcal subpopulation.

Animals↗
PubMed1975

Variant angina pectoris: Clinical and anatomic spectrum and results of coronary bypass surgery.

Twenty patients are described with the variant angina syndrome (recurrent angina at rest with S-T segment elevations occurring only during pain and no evolution of infarction). In contrast to patients previously reported on, all but one had progressive unstable angina before hospitalization. Angina was frequently associated with arrhythmias, including ventricular fibrillation (2 instances), ventricular tachycardia (4), frequent ventricular premature beats (5), atrioventricular block (4), sinus bradycardia (2), sinoatrial exit block (1) and supraventricular tachycardia (1). Seventeen patients had significant proximal stenosis of one or more coronary arteries with good distal vessels. Bypass surgery in 15 of these patients resulted in one noncardiac postoperative death, one perioperative infarction and relief of pain in all 14 survivors. After a 17 month mean follow-up period (range 4 to 38 months), all survivors are pain-free. Three patients had no significant coronary disease; one of these became asymptomatic with medical therapy, one continues to have angina and one died suddenly. Patients with normal coronary arteries could not be distinguished clinically or by electrocardiogram from those with severe obstructive lesions. This experience suggests that all patients with the variant angina syndrome should be studied by coronary angiography, and that most patients with significant fixed coronary lesions will do well after coronary bypass surgery.

Adult↗
PubMed1992

Central neurocytoma: histopathological variants and therapeutic approaches.

The central neurocytoma has recently been added to the differential diagnosis of intraventricular tumors. Histopathologically, this tumor is characterized by a uniform neoplastic cell population with features of neuronal differentiation. Central neurocytomas occur in young adults, develop in the area of the foramen of Monro, and are usually associated with the septum pellucidum. Initial reports appeared to indicate that these tumors are benign lesions with a favorable postoperative prognosis. The authors present clinical and neuropathological findings in a series of eight patients with central neurocytoma. An anterior transcallosal microneurosurgical approach yielded good outcomes. Postoperative radiation therapy was restricted to two patients with a malignant variant of central neurocytoma and one patient with a recurrent tumor. Observations of anaplastic variants of this neoplasm in two cases and local tumor recurrences in three indicate that the biological behavior and postoperative prognosis of central neurocytoma may not always be as favorable as previously assumed.

Adult↗