The diagnostic accuracy of 1.5 T versus 3 T non-echo-planar diffusion-weighted imaging in the detection of residual or recurrent cholesteatoma in the middle ear and mastoid.

PURPOSE AND BACKGROUND: This study retrospectively compares diagnostic performance of 1.5 T versus 3 T non-echo planar diffusion weighted imaging with or without additional T1 and T2 sequences in the detection of residual and/or recurrent cholesteatoma. METHODS: Patients with clinically suspected recurrent cholesteatoma or postoperative routine survey MR who subsequently underwent surgical procedure were retrospectively included (135 patients, 164 operated ears) from a large database. Patients underwent 1.5 T (128 ears) or 3 T MRI (36 ears), with non-echo planar DWI, T1 and T2 acquisitions. Two radiologists independently reassessed the images. Definitive surgical diagnosis was used as gold standard. Sensitivity, specificity and diagnostic odds ratio were evaluated. RESULTS: According to surgical diagnosis a cholesteatoma was present in 124 of 164 ears, corresponding with a prevalence of 75%. Sensitivity and specificity were lower for 3 T compared to 1.5 T, irrespective of whether additional T1 and T2-weighted sequences were used or not. Diagnostic odds ratios were higher for 1.5 T (34 and 12 for reader 1 and 2, respectively) compared to 3 T (3 and 4 for reader 1 and 2, respectively). Adding T1 and T2 sequences lowers sensitivity but increases specificity. CONCLUSION: Non-epi DWI for the detection of residual/recurrent cholesteatoma is preferably performed on 1.5 T scanners over 3 T. The use of additional sequences regarding detection of cholesteatoma is debatable as it lowers sensitivity but increases specificity. However, these sequences may also be of use in diagnosing complications and planning surgical procedures in some hospitals.

Identification of a genetically defined ultra-high-risk group in relapsed pediatric T-lymphoblastic leukemia.

In the search for genes that define critical steps of relapse in pediatric T-cell acute lymphoblastic leukemia (T-ALL) and can serve as prognostic markers, we performed targeted sequencing of 313 leukemia-related genes in 214 patients: 67 samples collected at the time of relapse and 147 at initial diagnosis. As relapse-specific genetic events, we identified activating mutations in NT5C2 (P=0.0001, Fisher's exact test), inactivation of TP53 (P=0.0007, Fisher's exact test) and duplication of chr17:q11.2-24.3 (P=0.0068, Fisher's exact test) in 32/67 of T-ALL relapse samples. Alterations of TP53 were frequently homozygous events, which significantly correlated with higher rates of copy number alterations in other genes compared with wild-type TP53 (P=0.0004, Mann-Whitney's test). We subsequently focused on mutations with prognostic impact and identified genes governing DNA integrity (TP53, n=8; USP7, n=4; MSH6, n=4), having key roles in the RAS signaling pathway (KRAS, NRAS, n=8), as well as IL7R (n=4) and CNOT3 (n=4) to be exclusively mutated in fatal relapses. These markers recognize 24/49 patients with a second event. In 17 of these patients with mostly refractory relapse and dire need for efficient treatment, we identified candidate targets for personalized therapy with p53 reactivating compounds, MEK inhibitors or JAK/STAT-inhibitors that may be incorporated in future treatment strategies.

Outcomes after resection and/or radiofrequency ablation for recurrence after treatment of colorectal liver metastases.

BACKGROUND: Repeat liver resection for colorectal liver metastases (CRLMs) is possible in a limited number of patients, with radiofrequency ablation (RFA) as an alternative for unresectable CRLMs. The aim of this study was to analyse survival rates with these interventions. METHODS: This was a database analysis of patients who underwent first and repeat interventions for synchronous and metachronous CRLMs between 2000 and 2013. Descriptive and survival statistics were calculated. RESULTS: Among 431 patients who underwent resection or RFA for CRLMs, 305 patients developed recurrences for which 160 repeat interventions (resection and/or RFA or ablative radiotherapy) were performed. In total, after 707 first or repeat interventions, 516 recurrences (73·0 per cent) developed, of which 276 were retreated curatively. At the time of first intervention, independent risk factors for death were lymph node-positive primary tumour (hazard ratio (HR) 1·40; P = 0·030), more than one CRLM (HR 1·53; P = 0·007), carcinoembryonic antigen level exceeding 200 ng/ml (HR 1·89; P = 0·020) and size of largest CRLM greater than 5 cm (HR 1·54; P = 0·014). The 5-year overall survival rates for liver resection and percutaneous RFA as first intervention were 51·9 and 53 per cent, with a median overall survival of 65·0 (95 per cent c.i. 47·3 to 82·6) and 62·1 (52·2 to 72·1) months, respectively. CONCLUSION: RFA had good oncological outcomes in patients with unresectable CRLMs. Radiofrequency ablation is progressively more applied with each additional intervention.

Prognostic value of genetic alterations in children with first bone marrow relapse of childhood B-cell precursor acute lymphoblastic leukemia.

Despite risk-adapted treatment, survival of children with relapse of acute lymphoblastic leukemia (ALL) remains poor compared with that of patients with initial diagnosis of ALL. Leukemia-associated genetic alterations may provide novel prognostic factors to refine present relapse treatment strategies. Therefore, we investigated the clinical relevance of 13 recurrent genetic alterations in 204 children treated uniformly for relapsed B-cell precursor ALL according to the ALL-REZ BFM 2002 protocol. The most common alterations were deletions of CDKN2A/2B, IKZF1, PAX5, ETV6, fusion of ETV6-RUNX1 and deletions and/or mutations of TP53. Multivariate analysis identified IKZF1 deletion and TP53 alteration as independent predictors of inferior outcome (P=0.002 and P=0.001). Next, we investigated how both alterations can improve the established risk stratification in relapsed ALL. Intermediate-risk relapse patients with low minimal residual disease are currently considered to have a good prognosis. In this group, deletion of IKZF1 and alteration of TP53 identify patients with significantly inferior outcome (P<0.001). In high-risk relapse patients, deletion of IKZF1 is strongly predictive of a second relapse after stem cell transplantation (P<0.001). We conclude that IKZF1 and TP53 represent relevant prognostic factors that should be considered in future risk assessment of children with relapsed ALL to indicate treatment intensification or intervention.

The diagnostic accuracy of non-echo-planar diffusion-weighted imaging in the detection of residual and/or recurrent cholesteatoma of the temporal bone.

BACKGROUND AND PURPOSE: Non-EPI DWI is a promising alternative to second-look surgery for the detection of residual and/or recurrent cholesteatoma. We evaluated the diagnostic accuracy, expressed as a positive predictive value, of MR imaging for the detection of residual and/or recurrent cholesteatoma in our hospital. MATERIALS AND METHODS: Fifty-six MR imaging studies were performed from 2005 to 2010 in patients having previously undergone surgery for cholesteatoma. Pre- and postgadolinium T1-weighted, T2-weighted, and non-EPI DWI sequences were performed and correlated with clinical and intraoperative findings. Twenty-seven patients underwent second-look surgery; 7 were under close clinical follow-up. Twenty-two patients without evidence of cholesteatoma were under regular follow-up (range, 14-44 months). RESULTS: Non-EPI DWI sequences showed increased DW signal intensity in 36 patients. Of those, 27 had second-look surgery, confirming cholesteatoma in 25 patients; in 1 patient, an empyema was diagnosed, and in the other patient, no cholesteatoma was found at surgery. In 2 patients who had not undergone surgery, increased DW signal intensity was accompanied by hyperintense signal intensity on T1-weighted images, consistent with transplanted fat in the postoperative cavity. The positive predictive value for detection of cholesteatoma was 93% (25/27). CONCLUSIONS: Residual and/or recurrent cholesteatomas after primary cholesteatoma surgery can be accurately detected by increased DW signal intensity on non-EPI DWI. However, DWI without conventional sequences increased the risk of misdiagnosis in our patient setting because transplanted fat within the postoperative cavity may show increased DW signal intensity.

Enhanced tumor therapy using vaccinia virus strain GLV-1h68 in combination with a ß-galactosidase-activatable prodrug seco-analog of duocarmycin SA.

Breast cancer is the most common cause of cancer-related death worldwide, thus remaining a crucial health problem among women despite advances in conventional therapy. Therefore, new alternative strategies are needed for effective diagnosis and treatment. One approach is the use of oncolytic viruses for gene-directed enzyme prodrug therapy. Here, the lacZ-carrying vaccinia virus (VACV) strain GLV-1h68 was used in combination with a ß-galactosidase-activatable prodrug derived from a seco-analog of the natural antibiotic duocarmycin SA. Tumor cell infection with the VACV strain GLV-1h68 led to production of ß-galactosidase, essential for the conversion of the prodrug to the toxic compound. Furthermore, drug-dependent cell kill and induction of the intrinsic apoptosis pathway in tumor cells was also observed on combination therapy using the prodrug and the GLV-1h68 strain, despite the fact that VACV strains encode antiapoptotic proteins. Moreover, GI-101A breast cancer xenografts were effectively treated by the combination therapy. In conclusion, the combination of a ß-galactosidase-activatable prodrug with a tumor-specific vaccinica virus strain encoding this enzyme, induced apoptosis in cultures of the human GI-101A breast cancer cells, in which a synergistic oncolytic effect was observed. Moreover, in vivo, additional prodrug treatment had beneficial effects on tumor regression in GLV-1h68-treated GI-101A-xenografted mice.

Synthesis of the first spacer containing prodrug of a duocarmycin analogue and determination of its biological activity.

The synthesis of the first spacer containing, duocarmycin analogue prodrug was realised, its biological properties evaluated and compared to its counterpart prodrug without a spacer unit. The synthesis comprises the manufacture of the new acetylated derivatives and of two double spacer systems, their activation and coupling to the pharmacophoric seco-drug (+)-. Unprecedented biological results were found as the new prodrug showed a fairly low QIC(50) value of 20, but on the other hand a high stability and very low DNA alkylation efficiency. These findings indicate a changed cytostatic mode of action induced by the self-immolative spacer moiety which was employed.

Determination of the biological activity and structure activity relationships of drugs based on the highly cytotoxic duocarmycins and CC-1065.

The natural antibiotics CC­1065 and the duocarmycins are highly cytotoxic compounds which however are not suitable for cancer therapy due to their general toxicity. We have developed glycosidic prodrugs of seco-analogues of these antibiotics for a selective cancer therapy using conjugates of glycohydrolases and tumour-selective monoclonal antibodies for the liberation of the drugs from the prodrugs predominantly at the tumour site. For the determination of structure activity relationships of the different seco-drugs, experiments addressing their interaction with synthetic DNA were performed. Using electro-spray mass spectrometry and high performance liquid chromatography, the experiments revealed a correlation of the stability of these drugs with their cytotoxicity in cell culture investigations. Furthermore, it was shown that the drugs bind to AT-rich regions of double-stranded DNA and the more cytotoxic drugs induce DNA fragmentation at room temperature in several of the selected DNA double-strands. Finally, an explanation for the very high cytotoxicity of CC-1065, the duocarmycins and analogous drugs is given.

Asymmetric synthesis and biological evaluation of glycosidic prodrugs for a selective cancer therapy.

A severe limitation in cancer therapy is the often insufficient differentiation between malign and benign tissue using known chemotherapeutics. One approach to decrease side effects is antibody-directed enzyme prodrug therapy (ADEPT). We have developed new glycosidic prodrugs such as (-)-(1S)-26 b based on the antibiotic (+)-duocarmycin SA ((+)-1) with a QIC(50) value of 3500 (QIC(50)=IC(50) of prodrug/IC(50) of prodrug+enzyme) and an IC(50) value for the corresponding drug (prodrug+enzyme) of 16 pM. The asymmetric synthesis of the precursor (-)-(1S)-19 was performed by arylation of the enantiomerically pure epoxide (+)-(S)-29 (> or = 98 % ee).

Predictive value of neonatal MRI with respect to late MRI findings and clinical outcome. A study in infants with periventricular densities on neonatal ultrasound.

PURPOSE: The aim of this study was to correlate hypoxic-ischemic white matter damage on neonatal MRI with MRI appearance and neurological outcome at the age of 1 1/2 years. PATIENTS AND METHODS: A sequential cohort of infants with periventricular densities on neonatal ultrasound was studied with neonatal MRI. Images of 46 infants with a mean gestational age of 31 weeks were obtained at a mean age of 20 days after birth and at 1 1/2 years. To establish agreement between the neonatal and follow-up MRI (general, motor, and visual scores), the weighted Cohen's kappa test was used. To establish the predictive power of neonatal MRI with respect to the neurologic indices at the age of 1 1/2 years, the sensitivity, specificity, and positive and negative predictive values were calculated. RESULTS: There was a moderately good to good agreement between the general, motor, and visual neonatal and follow-up MRI scores: weighted kappa = 0.59 (95% CI: 0.44 - 0.74), 0.82 (95% CI: 0.72 - 0.93), and 0.70 (95% CI: 0.56 - 0.84), respectively. Neonatal MRI scores provided a good prediction of the three neurological outcome measures (developmental delay, cerebral palsy, and cerebral visual impairment): sensitivity, specificity, and predictive values were high, with little difference between the three MRI scores. The 32 patients with (nearly) normal neonatal MRI scores were neurologically (nearly) normal at 1 1/2 years on all three outcome measures, whereas 8 patients with seriously abnormal neonatal MRI scores were neurologically abnormal at 1 1/2 years on all three outcome measures. CONCLUSION: Neonatal MRI is able to predict the precise localization and size of perinatal leukomalacia on follow-up MRI and provides a good prediction of neurological outcome at 1 1/2 years.

Alpha-1-antitrypsin genetic polymorphism in South Africa.

The alpha 1-antitrypsin (AAT) or protease inhibitor (Pi) genetic polymorphism was studied in 144 white, 100 coloured, 104 Indian and 127 black (Northern Sotho) healthy individuals (controls), in the Pretoria area. Their Pi phenotype and gene frequency distributions are compared with world-wide data on other population groups. The severely deficient Pi phenotypes S, Z and SZ jointly attain frequencies of 0.3-0.4% in coloureds and whites; in blacks and Indians the corresponding frequencies are very much lower. The implication for preventive medicine and public health is that in South Africa the sequelae of Pi deficiencies such as cirrhosis of the liver and/or emphysema of the lung are of practical importance in whites and coloureds and much less so in blacks and Indians. In 176 white breast cancer patients studied, the Pi phenotype and gene frequency distributions were found to be similar to those of healthy controls (not statistically significant). Cohorts of other patients were also phenotyped because of their low alpha 1-globulin concentrations in routine serum protein electrophoresis and/or their specific disease condition (cirrhosis of the liver or emphysema of the lung) known to be associated with AAT deficiency. These results are discussed in terms of their significance for family follow-up, genetic counselling and a preventive service. The need to avoid atmospheric pollution, especially cigarette smoke, is emphasised as a major and cost-effective preventive measure.

Maternal serum alpha-fetoprotein screening in Natal. Results of over 12 000 tests.

Mass screening of maternal serum alpha-fetoprotein levels for the prenatal detection of fetuses with neural tube defects (NTDs) was introduced in Natal during 1979. From then until 31 October 1982, 12318 pregnancies were monitored and 16 fetuses with NTDs identified. A further 7 abnormal fetuses, 3 with defects other than of the neural tube, were encountered. It is shown that the screening process is reliable and that it does not generate much additional work for ultrasonographers or other laboratories. Few problems related to the management of the screening programme were met; they are discussed with particular reference to the role of ultrasonography.

Genetic services in the State Health Department of the RSA. Development and structure.

Most developing countries have genetic counselling services. Although research and expertise in human genetics have reached unprecedented heights, health authorities have only recently acknowledged the practical application and economic value of genetic services in community health care. The development of community-based genetic services in the RSA since 1971 and the current organization and structure of the services in the State Health Department are described.

Screening for inborn errors of metabolism among mentally retarded patients. Outcome of a surgery at the Witrand Care and Rehabilitation Centre.

The prevalence of different types of inborn errors of metabolism among the mentally retarded patients at the Witrand Care and Rehabilitation Centre, were determined by means of a biochemical screening survey. These results are compared with those of other surveys in South Africa and abroad. One important result points to substantial differences in the recorded incidences of metabolic defects between surveys. This observation could partially be due to significant differences between the different studies in terms of methodology employed and sampling procedures. The questions raised in this regard are documented and discussed.

Biochemical polymorphisms in South African freshwater fish. Isoenzyme patterns in fish of the families Cyprinidae and Salmonidae.

Isoenzyme patterns were studied in local populations of the carp (Cyprinus carpio) and the bream (Sarotherodon mossambicus) of the Cyprinid family, and in the trout (Salmo giardneri) of the family Salmonidae. Homogenates of heart muscle extracts were used in the identification of PGI, NADP-IDH, PGM and 6-PGD. Polymorphisms found and gene frequencies obtained are discussed separately for each enzyme and species or population. In the bream, variation was found only at the PGI locus. In the carp only the PGM locus was polymorphic whereas both PGM and IDH showed variation in the trout. The variation at the PGM locus in the trout cannot support the three locus model suggested elsewhere and clearly indicates a single locus for the monomeric enzyme. The large variety of NADP-IDH types in trout not only illucidates the complexity of this locus but confirms a disomic mode of inheritance. Genetic differences in the trout populations could be related to possible advantages for management purposes.