Boston type I keratoprosthesis for treatment of gelatinous drop-like corneal dystrophy after repeated graft failure.

PURPOSE: To describe the use of a Boston type I keratoprosthesis as a secondary penetrating procedure to treat gelatinous drop-like corneal dystrophy (GDLD), with presentation of pathologic findings, genetic analysis, and discussion of other surgical options. METHODS: A 43-year-old woman with GDLD in both eyes, best corrected visual acuity (BCVA) of counting fingers in both eyes, and recurrent corneal opacification following two penetrating keratoplasties presented for visual rehabilitation. A Boston type I keratoprosthesis was implanted in her left eye after extracapsular clear lens extraction. RESULTS: The surgery was uneventful and one month after surgery, best corrected vision improved to 20/30, which has been maintained for a period of more than nine months. At the 12-month visit, her vision was noted to be diminished to 20/200 due to a retroprosthetic membrane and improved to 20/25 two weeks after a Yag capsulotomy. Histopathologic examination of the corneal specimen disclosed predominantly subepithelial amyloid deposition. Genetic analysis is presented. CONCLUSIONS: GDLD is a rare disorder of primary corneal amyloidosis. Recurrence of this condition following surgery is very common. Boston type I keratoprosthesis as a secondary procedure can be successful in restoring vision in affected patients.

Suicidal gene therapy in an NF-κB-controlled tumor environment as monitored by a secreted blood reporter.

The nuclear factor-κB (NF-κB) is known to be activated in many cancer types including lung, ovarian, astrocytomas, melanoma, prostate as well as glioblastoma, and has been shown to correlate with disease progression. We have cloned a novel NF-κB-based reporter system (five tandem repeats of NF-κB responsive genomic element (NF; 14 bp each)) to drive the expression cassette for both a fusion between the yeast cytosine deaminase and uracil phosphoribosyltransferase (CU) as a therapeutic gene and the secreted Gaussia luciferase (Gluc) as a blood reporter, separated by an internal ribosomal entry site (NF-CU-IGluc). We showed that malignant tumor cells have high expression of Gluc, which correlates to high activation of NF-κB. When NF-κB was further activated by tumor necrosis factor-α in these cells, we observed up to 10-fold increase in Gluc levels and therefore transgene expression in human glioma cells served to greatly enhance the sensitization of these cells to the prodrug, 5-fluorocytosine both in cultured cells and in vivo subcutaneous tumor xenograft model. This inducible system provides a tool to enhance the expression of imaging and therapeutic genes for cancer therapy.

Genetic heterogeneity of Beta thalassemia in Lebanon reflects historic and recent population migration.

Beta thalassemia is an autosomal recessive disorder characterized by reduced (beta(+)) or absent (beta(0)) beta-globin chain synthesis. In Lebanon it is the most predominant genetic defect. In this study we investigated the religious and geographic distribution of the beta-thalassemia mutations identified in Lebanon, and traced their precise origins. A total of 520 beta-globin chromosomes from patients of different religious and regional backgrounds was studied. Beta thalassemia mutations were identified using Amplification Refractory Mutation System (ARMS) PCR or direct gene sequencing. Six (IVS-I-110, IVS-I-1, IVS-I-6, IVS-II-1, cd 5 and the C > T substitution at cd 29) out of 20 beta-globin defects identified accounted for more than 86% of the total beta-thalassemia chromosomes. Sunni Muslims had the highest beta-thalassemia carrier rate and presented the greatest heterogeneity, with 16 different mutations. Shiite Muslims followed closely with 13 mutations, whereas Maronites represented 11.9% of all beta-thalassemic subjects and carried 7 different mutations. RFLP haplotype analysis showed that the observed genetic diversity originated from both new mutational events and gene flow from population migration. This study provides information about the types and distribution of beta-thalassemia mutations within each religious group and geographic region, which is essential for the implementation of screening and prevention programs.

Accurate and rapid prenatal diagnosis of the most frequent East Mediterranean beta-thalassemia mutations.

Beta-thalassemia is the most common genetic disorder in the Lebanese population. Of the 200 different mutations in the beta-globin gene that leads to thalassemia, the IVSI-110 (29.87%), IVSI-6 (20.74%), IVSI-1 (14.07%), IVSII-1 (9.13%), Cd29 (9.13%), and Cd30 (3.95%) mutations are the most frequent among Lebanese thalassemic patients. These mutations are also present at high frequencies in the East Mediterranean region. Due to this high prevalence of certain beta-thalassemia mutations, a rapid technique for the prenatal diagnosis of these mutations was implemented. The technique used is based on Real-Time PCR quantification and melting curve analysis of the amplified fragment using the LightCycler. The DNA samples used for amplification were obtained from CVS or amniotic fluid. Six mutations were easily and efficiently detected using only 3 sets of probes. With this method, mutant genotypes can be easily distinguished from normal alleles. In prenatal diagnosis, the accuracy and the speed of testing are paramount. The method of prenatal beta-thalassemia mutations detection described here is efficient and fast, with the entire procedure including DNA preparation taking less than half a workday. It is safe, does not involve radioactivity, and is accurate showing 100% concordance with conventional DNA sequencing methods.

Host and environmental factors defining the epidemiology of type 1 diabetes mellitus in a group of Lebanese children and young adults.

The effect of a number of host and environmental factors on the onset of type 1 diabetes mellitus (DM1) in a group of Lebanese children and young adults was studied. Results showed that DM1 in a group of 253 patients presented no gender preference and that the age of onset was similar in both genders. The overall body mass index reflected good metabolic control. HbA1c had a mean value of 8.98%, suggesting poor glucose control. Family history of DM1 and type 2 diabetes mellitus as well as consanguinity in patients' families were not different from those reported in the literature. Finally, onset of DM1 showed seasonal variation, peaking during winter months. DM1 showed a higher prevalence of onset among children born first and a decreased incidence as birth order increased. This study provides valuable data for the diagnosis, control and prevention of DM1 in children.

Beta-globin gene cluster haplotypes and HbF levels are not the only modulators of sickle cell disease in Lebanon.

Sickle cell disease (SCD) is an inherited autosomal recessive disorder of the beta-globin chain. Despite the fact that all subjects with SCD have the same single base pair mutation, the severity of the clinical and hematological manifestations is extremely variable. This study examined for the first time in Lebanon the correlation between the clinical manifestation of SCD and the beta-globin gene haplotypes. The haplotypes of 50 patients diagnosed with SCD were determined using polymerase chain reaction amplification of fragments containing nine polymorphic restriction sites around and within the epsilon-Ggamma-Agamma-psibeta-delta-beta-globin gene complex. Most reported haplotypes were found in our population with the Benin haplotype as the most prevalent one. When the patients were divided according to their HbF levels into three groups (Group A: HbF < 5%, Group B: HbF between 5 and 15%, and Group C: HbF > 15%), surprisingly, the highest levels of HbF were associated with the most severe clinical cases. Our findings suggest that fetal hemoglobin levels are important but not the only parameters that affect the severity of the disease. In addition, the high levels of HbF in patients with CAR haplotypes did not seem to ameliorate the severity of symptoms, suggesting that genetic factors other than haplotypes are the major determinants of increased HbF levels in Lebanon.

Prevalence of genital human papillomavirus among Lebanese women.

PURPOSE: The purpose of this study was to determine the prevalence of human papillomavirus (HPV), and more specifically of HPV 16, in a group of Lebanese women. MATERIALS AND METHODS: Type-specific prevalence of cervical HPV and the presence of cytological abnormalities were determined in a cohort of Lebanese women. The population included 1,026 women, 18-76 years, seeking routine gynecological care at a tertiary care center. Demographic and behavioral data were collected. HPV DNA was detected in cervical scrapes by polymerase chain reaction using consensus primers. Cervical cytological abnormalities were identified by Papanicoleau (Pap) smears. RESULTS: The mean age of our population was 40 +/- 11.3 years. General HPV DNA was detected in 50 patients (4.9%). The high-risk HPV type 16 DNA was detected in 31 patients (3%). Patients with HPV 16 were more likely to have an abnormal pap smear than those with negative tests (6.6% vs 1.6%, p < 0.05), and more likely, but not significantly, to be smokers (21.4% vs 18.4%, p = 0.5). The age-specific prevalence of HPV increased with age and peaked at 60-69 years. CONCLUSIONS: The prevalence of HPV in this small group of Lebanese women is similar to its prevalence in the Mediterranean countries. The presence of HPV, its known association with the development of cervical neoplasia, and the lack of a universal screening program for cervical cancer in our country should be used to enforce implementation of proper screening programs.

Leptin levels in patients with type 1 diabetes receiving intensive insulin therapy compared with those in patients receiving conventional insulin therapy.

Several reports suggest that insulin may have a role in the regulation of serum leptin levels, and this is related to the fact that serum leptin levels generally indicate the amount of body fat. Studies show that leptin levels are low in newly diagnosed patients with Type-1 diabetes (T1 DM) and increase after institution of insulin therapy. This study was designed to test whether serum leptin levels are higher in patients receiving intensive insulin therapy (IIT) compared to conventional insulin therapy (CIT). Young patients with T1 DM were studied, 23 on IIT and 23 on CIT. The patients were matched for age (19+/-3 and 20+/-5 yr, respectively), duration of diabetes (8+/-5 and 10+/-6 yr, respectively) and BMI (24+/-4 and 23+/-3 kg/m2, respectively). Leptin levels were higher in IIT compared to CIT (13+/-12 vs 7+/-7 ng/ml, respectively, p<0.05). The results of this study demonstrate that patients on IIT have higher leptin levels than patients on CIT. This increase in leptin level in IIT patients is independent of changes in bw and is probably due to the stimulatory effect of insulin on leptin production.

Type-2 diabetes family history delays the onset of type-1 diabetes.

Type-1 diabetes (T1D) is an autoimmune disease leading to insulin deficiency. Its occurrence is influenced by genetic and environmental factors. The human leukocyte antigen (HLA) region on chromosome 6 accounts for 45% of the genetic susceptibility for the disease, mainly the HLA-DQB1*0201 and HLA-DQB1*0302 alleles. Among the environmental factors involved, early exposure to cow's milk seems to be a trigger. In this study, we investigated the occurrence of T1D in 253 Lebanese Caucasian patients, in relation to HLA-DQB1*0201, HLA-DQB1*0302, HLA-DQB1*0602, gender, and early exposure to cow's milk, as well as to family history of T1D and type-2 diabetes (T2D). Our genetic analysis results show that in the patients studied, 77% and 40% were positive for BQ1*0201 and BQ1*0302, respectively. As for BQ1*0602, only 0.8% of patients were positive for this T1D protective allele, compared with 24% among the controls. Furthermore, our results did not show any gender preference of the disease or any effects of early intake of cow's milk on the age at onset of T1D. When family history of T2D or T1D was studied, our results show a novel finding whereby an immediate family history of T2D, but not T1D, delays the age at onset of T1D.

The DD genotype of the ACE gene polymorphism is associated with diabetic nephropathy in the type-1 diabetics.

Genetic factors are involved in the development of diabetic nephropathy in type-1 diabetes. We are examining the association of the angiotensin-converting enzyme (ACE), insertion/deletion (I/D) polymorphism with the presence of diabetic nephropathy in type-1 diabetic patients. 52 type-1 diabetic patients with diabetic nephropathy (30 with either microalbuminuria or macroalbuminuria and 22 with end stage renal disease on dialysis) were compared with 10 type-1 diabetic patients with normoalbuminuria and duration of disease longer than 15 years and 27 non-diabetic healthy subjects. We found that the D-allele frequency was higher in patients with nephropathy than in the healthy and normoalbuminuric controls. There was an association in the DD polymorphism of the ACE gene with patients with diabetic nephropathy and not with the control subjects. We conclude that the DD genotype of ACE gene polymorphism is associated with diabetic nephropathy in patients with type-1 diabetes mellitus.

Chemical cleavage of 5'-linked protein from tobacco ringspot virus genomic RNAs and characterization of the protein-RNA linkage.

Each of the two genomic RNAs of tobacco ringspot nepovirus is known to have a 5'-linked protein, the VPg. We report a simplified analysis of the covalent VPg-RNA connection that allowed us to identify the 5' nucleotide residue of each genomic RNA and its phosphodiester link to a specific serine residue of the VPg, without resorting to in vivo labeling with 32P, in vitro radioiodination, or separation of the two genomic RNAs. Unfractionated genomic RNA was incubated with an oligodeoxyribonucleotide specific for the 5' region of either RNA 1 or RNA 2 and ribonuclease H. Reaction products were 3'-end-labeled and were fractionated by gel electrophoresis. The most highly labeled product derived from each genomic RNA was identified as a VPg-oligoribonucleotide (VPg-5'-oligo) by its sensitivity to proteinase. In a presumed beta-elimination reaction that apparently was more rapid than phosphodiester cleavage, incubation in alkaline sodium bicarbonate released a rapidly migrating product, 5'-oligo. Phosphatase-treated 5'-oligo accepted 5'-label in a polynucleotide kinase-catalyzed reaction, and uridylate was identified as the 5' terminal residue for both RNA 1 and RNA 2. Results from Edman degradation of the VPg suggest that the VPg is linked at serine 5 to the 5' uridylate of each genomic RNA.

Increase of satellite tobacco ringspot virus RNA initiated by inoculating circular RNA.

A small satellite RNA of tobacco ringspot virus (sTRSV RNA) generates circular and linear molecules of unit length and repetitive sequence, linear multimers during replication. The phosphodiester junction joining the unit satellite RNA sequences in multimeric and circular RNA resisted base-catalyzed cleavage in circles but not in linear dimers. We postulate that junctions of multimeric satellite RNA form during synthesis of the polyribonucleotide chain, whereas those of circular RNA result from a ligation reaction that introduces a group blocking the junction 2'-hydroxyl. To test the relative effectiveness of linear and circular satellite RNAs in initiating replication, we inoculated onto bean (Phaseolus vulgaris cv Black Valentine) the four possible pairs of satellite RNA molecules, one member of each pair having the wild-type sTRSV RNA sequence and the other that of the replicating mutant 51AG/212CU, with each sequence provided as the unit circular or linear form. The relative amounts of wild-type and mutant satellite RNA sequence recovered from progeny virions reflected their relative abundances in the inoculum without regard to whether the sequence was supplied as a linear or a circular molecule. These results are consistent with models for the replication of the satellite RNA in which a circular form of the satellite RNA is a template for rolling circle transcription or is otherwise a replication intermediate or is readily converted to an intermediate. We also show that a circular form of a nonaccumulating satellite RNA mutant induced an increase in a satellite RNA that is endogenous to some tobacco ringspot virus virion preparations, as demonstrated previously for the linear form.