Ants Toi
University of Toronto, Faculty of Medicine, Faculty Member
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Serum insulin-like growth factor-I (IGF-I) levels at the higher end of the reference range have been associated with increased risk for the future development of prostate cancer. We determined whether high serum IGF-I levels are... more
Serum insulin-like growth factor-I (IGF-I) levels at the higher end of the reference range have been associated with increased risk for the future development of prostate cancer. We determined whether high serum IGF-I levels are associated with precancerous lesions of the prostate. We conducted a case-control study to determine whether high serum IGF-I levels were associated with the presence of
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ABSTRACT Background: Antimicrobial prophylaxis prior to transrectal ultrasound (TRUS)-guided prostate biopsy reduces the risk of infectious complications. Despite increasing E. coli resistance to fluoroquinolones, oral ciprofloxacin... more
ABSTRACT Background: Antimicrobial prophylaxis prior to transrectal ultrasound (TRUS)-guided prostate biopsy reduces the risk of infectious complications. Despite increasing E. coli resistance to fluoroquinolones, oral ciprofloxacin remains the most widely used agent for this indication. We reviewed the temporal trends of infection-related complications following TRUS-guided prostate biopsy at Princess Margaret Cancer Center, a Canadian tertiary care hospital where ciprofloxacin prophylaxis is used. Methods: Surveillance for complications following TRUS-guided prostate biopsy at our center has been conducted since 2003. Complications that occurred within 30-days of the procedure were included. Definite infections were defined as either a positive blood or urine culture in a patient meeting National Healthcare Safety Network (NHSN) criteria for bloodstream or urinary tract infection, respectively. Possible infections were defined as empiric treatment for cystitis, pyelonephritis, prostatitis, epididymo-orchitis, or sepsis without culture confirmation. Results: Of 19279 men who underwent TRUS-guided prostate biopsy between 2003 and 2013, 159 (0.8%) developed infectious complications. Between 2006 and 2013, definite urinary tract infection increased from 0.05% to 0.8% (p<.0001); bloodstream infections increased from 0.1% to 0.6% (p<0.0001); and overall infections, including definite and possible infections, increased from 0.3% to 1.9% (p<.0001) (Figure). E. coli represented (85/89) 95% of isolates from urine and blood cultures of which 93% were resistant to ciprofloxacin. Resistance of E. coli to trimethoprim/sulfamethoxazole, gentamicin, cefazolin, ceftriaxone, and nitrofurantoin was 58%, 42%, 33%, 32%, and 8%, respectively. Conclusion: The proportion of TRUS-guided prostate biopsies associated with infectious complications has increased significantly over the past decade, likely driven by the emergence of E. coli resistance to ciprofloxacin. Emerging antibiotic resistance may make current prophylaxis strategies with ciprofloxacin less effective, emphasizing the need for prospective evaluation of other prophylactic regimens and other non-antibiotic prevention strategies.
The human kallikrein-2 (hK2) protein and two single nucleotide polymorphism (SNPs) (rs2664155, rs198977) of the gene are associated with prostate cancer risk. We examined whether hK2 protein and gene SNPs predict prostate cancer at the... more
The human kallikrein-2 (hK2) protein and two single nucleotide polymorphism (SNPs) (rs2664155, rs198977) of the gene are associated with prostate cancer risk. We examined whether hK2 protein and gene SNPs predict prostate cancer at the time of repeat biopsy. We prospectively offered a repeat biopsy to men with a negative prostate biopsy performed for a PSA >4.0 ng/mL or abnormal Digital Rectal Exam (DRE) between 2001-2005. We genotyped and measured serum hK2 levels in 941 men who underwent a repeat prostate biopsy. Logistic regression analyses were conducted to determine the significance of KLK2 SNPs and hK2 levels for predicting cancer at repeat biopsy. Of the 941 patients, 180 (19.1%) were found to have cancer. The rs198977 SNP was positively associated with cancer at repeat biopsy (OR variant T allele = 1.8, 95% CI: 1.04-3.13, p = 0.049). When combined, the odds ratio for prostate cancer for patients with high hK2 levels and the variant T-allele of rs198977 was 3.77 (95% CI: 1...
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The diastrophic dysplasia family of osteochondrodysplasias comprises a spectrum of skeletal diseases characterized by abnormal growth and remodelling of cartilage and bone. They are caused by mutations in the diastrophic dysplasia sulfate... more
The diastrophic dysplasia family of osteochondrodysplasias comprises a spectrum of skeletal diseases characterized by abnormal growth and remodelling of cartilage and bone. They are caused by mutations in the diastrophic dysplasia sulfate transporter (DTDST) gene. Different defects in this gene product give rise to the variety of phenotypes based on the level of residual transport capacity. We reported a case
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Research Interests: Urology, Polymorphism, Prostate Cancer, Gene Prediction, Humans, and 17 moreMale, Oxidoreductases, Control Design, Follow-up studies, Risk factors, Logistic Regression Analysis, Phenotype, Enzyme, Clinical Sciences, Aged, Middle Aged, Odds ratio, Disease Progression, Risk Factors, Radical Prostatectomy, Genetic Markers, and Confidence Interval
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We report the prenatal findings in two cases of Beals syndrome. Both pregnancies presented with clinical features of arthrogryposis multiplex congenita/fetal akinesia syndrome (AMC/FAS), including clenched fists and multiple joint... more
We report the prenatal findings in two cases of Beals syndrome. Both pregnancies presented with clinical features of arthrogryposis multiplex congenita/fetal akinesia syndrome (AMC/FAS), including clenched fists and multiple joint contractures on repeat prenatal ultrasound examinations. The first case was diagnosed as having Beals syndrome on physical examination shortly after birth and the diagnosis was confirmed by DNA analysis, shown as a point mutation in the fibrillin 2 (FBN2) gene. The second case was diagnosed with Beals syndrome following microarray analysis on amniocytes, which showed a deletion of the FBN2 gene. Although most cases with AMC/FAS carry a poor prognosis, Beals syndrome is consistent with normal cognitive development and a better prognosis. Thus, making the correct diagnosis is crucial, both pre- and postnatally, for accurate counseling and management.
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Transrectal ultrasound and ultrasound guided prostate biopsy is the current standard for detecting prostate cancer. Newer techniques such as elastography and contrast enhanced ultrasound may help in lesion detection and monitoring.... more
Transrectal ultrasound and ultrasound guided prostate biopsy is the current standard for detecting prostate cancer. Newer techniques such as elastography and contrast enhanced ultrasound may help in lesion detection and monitoring. Advances are occurring in several areas including multiparametric MRI, understanding of the nature of prostate cancer and new therapies including focal therapy and active surveillance. These changes are creating an increasing role for targeted biopsies following MRI and for use of MRI for treatment monitoring.
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The cerebral cortex develops in three overlapping stages: cell proliferation, neuronal migration, and cortical organization. Abnormal neuronal migration may result in lissencephaly, which is characterized by either the absence (agyria) or... more
The cerebral cortex develops in three overlapping stages: cell proliferation, neuronal migration, and cortical organization. Abnormal neuronal migration may result in lissencephaly, which is characterized by either the absence (agyria) or the paucity (pachygyria) of cerebral convolutions. The two main clinicopathologic types of lissencephaly may be differentiated according to their prenatal imaging features. Other cranial and extracranial abnormalities also may occur in association with lissencephaly. The prognosis is often poor, but prenatal diagnosis allows appropriate counseling and optimization of obstetric management. Familiarity with the normal ultrasonographic (US) and magnetic resonance (MR) imaging appearances of the fetal cerebral cortex at various stages of gestation is essential for the early detection of abnormal sulcal development. The primary fissures and sulci that can be examined with prenatal US and MR imaging include the parieto-occipital fissure, calcarine fissure, cingulate sulcus, convexity sulci, and sylvian fissure and insula.
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We describe the finding of cavum veli interpositi (CVI) on fetal ultrasound and MRI and the postnatal MRI and developmental follow-up in two cases. The first case was diagnosed on fetal ultrasound at 33... more
We describe the finding of cavum veli interpositi (CVI) on fetal ultrasound and MRI and the postnatal MRI and developmental follow-up in two cases. The first case was diagnosed on fetal ultrasound at 33 weeks' gestation and confirmed on fetal MRI. No abnormalities were detected on postnatal examinations and the brain MRI at 1 year of age showed no changes. At 4 years of age, his growth and development were normal.The second case was diagnosed with CVI on fetal ultrasound and MRI at 33.5 weeks' gestation. Postnatal examination showed no abnormalities, and brain MRI at 8 months of age revealed that the CVI was unchanged, but there was a dilated cavum septum pellucidum and cavum vergae. Her growth and development during the first 4 years of life were normal. CVI is a rare fetal ultrasound finding, which seems to be benign. However, further neurodevelopmental follow-up is needed to confirm this observation.
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Congenital cardiac diverticula are rare abnormalities that may occur as isolated malformations. In this report, we describe a case of an isolated congenital cardiac diverticulum complicated by a large serous pericardial effusion diagnosed... more
Congenital cardiac diverticula are rare abnormalities that may occur as isolated malformations. In this report, we describe a case of an isolated congenital cardiac diverticulum complicated by a large serous pericardial effusion diagnosed ultrasonographically at 19 weeks' gestation. Therapeutic pericardiocentesis at 20 weeks' gestation resulted in complete resolution of the effusion with a normal fetal outcome. There is only one previous report of a prenatal diagnosis of a cardiac diverticulum complicated by a pericardial effusion and that patient underwent termination of pregnancy (Carles et al., 1995). Given the otherwise favourable prognosis for this lesion, and the excellent response in this case, pericardiocentesis should be considered in similar cases.
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We report a patient diagnosed prenatally on routine fetal ultrasound, at 30 weeks' gestation, with subdural haemorrhage. The mother had suffered a mild abdominal trauma and had Factor XI deficiency; however, both were felt to be... more
We report a patient diagnosed prenatally on routine fetal ultrasound, at 30 weeks' gestation, with subdural haemorrhage. The mother had suffered a mild abdominal trauma and had Factor XI deficiency; however, both were felt to be aetiologically insignificant. Prenatal follow-up ...
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The objective of this study is to describe the prenatal sonographic features and the results of DNA analysis on three fetuses with dyssegmental dysplasia, Silverman-Handmaker type (DD-SH). A retrospective review of three fetuses with... more
The objective of this study is to describe the prenatal sonographic features and the results of DNA analysis on three fetuses with dyssegmental dysplasia, Silverman-Handmaker type (DD-SH). A retrospective review of three fetuses with confirmed DD-SH was conducted. The fetal ultrasound findings, the radiological characteristics, and the results of the mutation analysis of the heparan sulphate perlecan gene 2 (HSPG2) were reviewed. There were three cases in two families with DD-SH diagnosed prenatally. The main prenatal ultrasound and the radiological features of DD-SH were severe limb shortening and vertebral segmentation and fusion defects (anisospondyly). The DNA analysis of the HSPG2 gene showed that the two affected fetuses in a nonconsanguineous family had a compound heterozygote for the c.646G > T transversion in exon 7 and a c.5788C > T transition in exon 46. The fetus born to the consanguineous couple had a homozygous mutation c.1356-27_1507 + 59del. DD-SH can be diagnosed prenatally using fetal ultrasound as early as 13 weeks. Xrays and DNA analysis of the HSPG2 gene are important for the confirmation of the diagnosis and for the preimplantation and prenatal diagnosis in pregnancies at risk.
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To determine the visualization rates of fetal anatomic structures by three-dimensional ultrasound (3DUS) at 12-13 weeks of gestation. This was a prospective observational study of women presenting for nuchal translucency ultrasound. Five... more
To determine the visualization rates of fetal anatomic structures by three-dimensional ultrasound (3DUS) at 12-13 weeks of gestation. This was a prospective observational study of women presenting for nuchal translucency ultrasound. Five 3D volumes of the fetus were acquired transabdominally. Two investigators independently reviewed the stored volumes offline following a standardized protocol. One hundred singleton fetuses were examined. The mean time for 3D volumes acquisition was 4.8 min; and for 3D review 17 min. Anatomic structures were seen as follows: cranium, lateral cerebral ventricles and abdominal wall 100%; stomach, vertebrae, upper and lower limbs >or= 94%; face 71%, bladder 58%, both kidneys 39%, skin overlying spine 26% and heart 18%. Agreement between two observers ranged from 100% (for head, abdominal wall and lower limbs) to 43% (for visualization of skin overlying spine). A complete basic anatomic survey was achieved in 11.4% of the 12-week fetuses and 33.3% of the 13-week fetuses (p-value = 0.038). First-trimester transabdominal 3DUS was adequate for assessment of the head, abdominal wall, stomach, limbs and vertebral alignment. It was less effective for evaluating the heart and intactness of the skin over the spine.
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Document patient choices and screening performance (false positive and detection rates) when three improved Down syndrome screening protocols were introduced coincidentally. Second-trimester... more
Document patient choices and screening performance (false positive and detection rates) when three improved Down syndrome screening protocols were introduced coincidentally. Second-trimester 'triple marker' screening was expanded by adding second-trimester dimeric inhibin-A (four-marker), with or without first-trimester pregnancy-associated plasma protein-A (five-marker). Nuchal translucency (NT) measurements were included when available from accredited sonographers (six-marker). For assigning risk, two sets of marker distribution parameters were evaluated. Over 3.5 years, 8571 women enrolled (median age 30.6 years). Uptake of the four-, five- and six-marker protocols was 18%, 46% and 36%, respectively. Of those selecting an integrated test (five or six markers), 9.7% did not provide the second trimester serum sample. False positive rates decreased with added markers (5.2%, 5.1% and 2.5%, respectively) and varied between the two parameter sets, while detection remained high. Overall, 21 of 23 cases were detected (91%, 95% CI 73-98%) at a 4.2% false positive rate (95% CI 3.3-5.1%). Integrated screening protocols were chosen 4.6 times more often than four-marker screening (82% vs. 18% uptake). Overall detection was higher and false positives lower, consistent with recent guidelines. Important performance factors include gestational dating method, risk cut-off, and the parameter set used to assign risk.