Genetic analysis of Iranian autosomal dominant polycystic kidney disease: new insight to haplotype analysis

Autosomal Dominant Polycystic Kidney Disease (ADPKD) caused by mutations in two PKD1 and PKD2 genes. Due to the complexity of the PKD1 gene, its direct mutation screening is an expensive and time-consuming procedure. Pedigree-based haplotype analysis is a useful indirect approach to identify the responsible gene in families with multiple affected individuals, before direct mutation analysis. Here, we applied this approach to investigate 15 appropriate unrelated ADPKD families, selected from 25 families, who referred for genetic counseling. Four polymorphic microsatellite markers were selected around each PKD1 and PKD2 loci. In addition, by investigating the genomic regions, two novel flanking tetranucleotide STR markers were identified. Haplotype analysis and calculating Lod score confirmed linkage to PKD1 in 9 families (60%) and to PKD2 in 2 families (13%). Linkage to both loci was excluded in one family (6.6%). In 2 families (13%) the Lod scores were inconclusive. Causative mutation was identified successfully by direct analysis in two families with confirmed linkage, one to PKD1 and another to PKD2 locus. The study showed that determining the causative locus prior to direct mutation analysis is an efficient strategy to reduce the resources required for genetic analysis of ADPKD families. This is more prominent in PKD2-linked families. Selection of suitable markers, and appropriate PCR multiplexing strategy, using fluorescent labeled primers and 3 primer system, will also add value to this approach.

Correlation between brain cortex metabolic and perfusion functions in subjective idiopathic tinnitus

OBJECTIVES

Subjective tinnitus has associated with abnormal brain metabolism and perfusion found in functional imaging studies by fluorodeoxyglucose (FDG) and technetium99m (TC99m). But there is no study evaluating the association of brain metabolism and perfusion abnormalities in a group of these subjects. The aim of this study was to investigate if there is any significant correlation between the brain perfusion and metabolism abnormalities in subjects with tinnitus.

MATERIALS AND METHODS

In this cross-sectional study, 52 patients were undergone TC99m-ECD single photon emission computerized tomography (SPECT) scan and F18-FDG positron emission tomography (PET). The results of PET and SPECT scanning were fused with MRI to accurate anatomical localization of abnormalities. The analysis was performed using Kendal's correlation, t-test and chi square.

RESULTS

Assessing these 52 tinnitus subjects (containing 42 males [76.4%]) showed that a significant correlation was found between the brain metabolic function and perfusion (p value 0.001).

Pattern of brain blood perfusion in tinnitus patients using technetium-99m SPECT imaging

BACKGROUND AND PURPOSE

Tinnitus is associated with an increased activity in central auditory system as demonstrated by neuroimaging studies. Brain perfusion scanning using single photon emission computed tomography (SPECT) was done to understand the pattern of brain blood perfusion of tinnitus subjects and find the areas which are mostly abnormal in these patients.

MATERIALS AND METHODS

A number of 122 patients with tinnitus were enrolled to this cross-sectional study. They underwent SPECT and magnetic resonance imaging (MRI) of brain, and the images were fused to find the regions with abnormal perfusion.

RESULTS

SPECT scan results were abnormal in 101 patients (83%). Most patients had bilateral abnormal perfusion (N = 65, 53.3%), and most subjects had abnormality in middle-temporal gyrus (N = 83, 68%) and temporoparietal cortex (N = 46, 37.7%). Patients with multifocal involvement had the least mean age than other 2 groups (patients with no abnormality and unifocal abnormality) (P value = 0.045).

CONCLUSIONS

Brain blood perfusion pattern differs in patient with tinnitus than others. These patients have brain perfusion abnormality, mostly in auditory gyrus (middle temporal) and associative cortex (temporoparietal cortex). Multifocal abnormalities might be due to more cognitive and emotional brain centers involvement due to tinnitus or more stress and anxiety of tinnitus in the young patients.

Functional brain abnormalities localized in 55 chronic tinnitus patients: fusion of SPECT coincidence imaging and MRI

Tinnitus is often defined as the perception of sounds or noise in the absence of any external auditory stimuli. The pathophysiology of subjective idiopathic tinnitus remains unclear. The aim of this study was to investigate the functional brain activities and possible involved cerebral areas in subjective idiopathic tinnitus patients by means of single photon emission computerized tomography (SPECT) coincidence imaging, which was fused with magnetic resonance imaging (MRI). In this cross-sectional study, 56 patients (1 subject excluded) with subjective tinnitus and 8 healthy controls were enrolled. After intravenous injection of 5 mCi F18-FDG (fluorodeoxyglucose), all subjects underwent a brain SPECT coincidence scan, which was then superimposed on their MRIs. In the eight regions of interest (middle temporal, inferotemporal, medial temporal, lateral temporal, temporoparietal, frontal, frontoparietal, and parietal areas), the more pronounced values were represented in medial temporal, inferotemporal, and temporoparietal areas, which showed more important proportion of associative auditory cortices in functional attributions of tinnitus than primary auditory cortex. Brain coincidence SPECT scan, when fused on MRI is a valuable technique in the assessment of patients with tinnitus and could show the significant role of different regions of central nervous system in functional attributions of tinnitus.

Evaluation of [(201)Tl](III) Vancomycin in normal rats

BACKGROUND

Tl-201 has potential in the preparation of radiolabelled compounds similar to its homologues, like In-111 and radiogallium. In this paper, recently prepared [(201)Tl](III) vancomycin complex ([(201)Tl](III)VAN) has been evaluated for its biological properties.

MATERIAL AND METHODS

[(201)Tl](III)VAN was prepared according to the optimized conditions followed by biodistribution studies in normal rats for up to 52 h. The Staphylococcus aurous specific binding was checked in vitro. The complex was finally injected to normal rats. Tracer SPECT images were obtained in normal animals and compared to those of (67)Ga-citrate.

RESULTS

Freshly-prepared [(201)Tl](III)VAN batches (radiochemical yield > 99%, radiochemical purity > 98%, specific activity approximately 1.2 Ci/mmol) showed a similar biodistribution to that of unlabeled vancomycin. The microorganism binding ratios were 3 and 9 for tracer (201)Tl(3+) and tracer (201)Tl(III)DTPA, respectively, suggesting the preservation of the tracer bioactivity. As a nonspecific cell penetrating tracer, [(201)Tl](III)DTPA was used.

Association of hyperglycemia on allograft function in the early period after renal transplantation

Hyperglycemia is common following renal transplantation. This study was conducted to evaluate the relationship of perioperative serum glucose levels and acute rejection in 100 nondiabetic patients who underwent renal transplantation. Blood glucose was measured immediately following surgery and every 6 hours during the first 48 hours posttransplant as well as for 1 month to evaluate occurrence of acute rejection episodes (ARE). The rate of ARE was 33%. The mean blood glucose level immediately after surgery in patients with versus without ARE was 249.67 +/- 61.78 and 184.82 +/- 73.35 mg/dL, respectively (P=.000). There was no significant correlation between ARE and donor or recipient age or sex, delayed graft function, type of donor, or treatment. This study suggested a correlation between immediate blood glucose and ARE. In this regard, blood glucose monitoring and control during operation and immediate postoperatively may reduce the acute rejection rate.

Evaluation of [67Ga]-insulin for insulin receptor imaging

BACKGROUND

Radiolabelled human recombinant insulin can be used for the imaging of insulin receptors in some tumours where FDG has natural uptake and diminishes the value of its imaging.

MATERIAL AND METHODS

Insulin was successively labelled with [(67)Ga]-gallium chloride after conjugation with freshly prepared cyclic DTPA-dianhydride (HPLC radiochemical purity assay > 96%) followed by biodistribution studies in normal rats, white blood cell labelling and preliminary SPECT studies.

RESULTS

In vitro studies demonstrated the retention of radiolabelled insulin receptor affinity using freshly prepared human white blood cells at different blood sugar conditions. Preliminary in vivo studies in a normal rat model was performed to determine the biodistribution of the radioimmunoconjugate at up to 44 h. SPECT images revealed high uptake of the liver.

CONCLUSION

Radiolabelled insulin is stable enough to be used in biological studies in order to image insulin receptors in diabetic conditions as well as possible tumour imaging applications. The data was consistent with other radiolabelled insulin studies.