p34 is a novel regulator of the oncogenic behavior of NEDD4-1 and PTEN

PTEN is one of the most frequently mutated or deleted tumor suppressors in human cancers. NEDD4-1 was recently identified as the E3 ubiquitin ligase for PTEN; however, a number of important questions remain regarding the role of ubiquitination in regulating PTEN function and the mechanisms by which PTEN ubiquitination is regulated. In the present study, we demonstrated that p34, which was identified as a binding partner of NEDD4-1, controls PTEN ubiquitination by regulating NEDD4-1 protein stability. p34 interacts with the WW1 domain of NEDD4-1, an interaction that enhances NEDD4-1 stability. Expression of p34 promotes PTEN poly-ubiquitination, leading to PTEN protein degradation, whereas p34 knockdown results in PTEN mono-ubiquitination. Notably, an inverse correlation between PTEN and p34/NEDD4-1 levels was confirmed in tumor samples from colon cancer patients. Thus, p34 acts as a key regulator of the oncogenic behavior of NEDD4-1 and PTEN.

A nonintrusive temperature measuring system for estimating deep body temperature in bed

Deep body temperature is an important indicator that reflects human being's overall physiological states. Existing deep body temperature monitoring systems are too invasive to apply to awake patients for a long time. Therefore, we proposed a nonintrusive deep body temperature measuring system. To estimate deep body temperature nonintrusively, a dual-heat-flux probe and double-sensor probes were embedded in a neck pillow. When a patient uses the neck pillow to rest, the deep body temperature can be assessed using one of the thermometer probes embedded in the neck pillow. We could estimate deep body temperature in 3 different sleep positions. Also, to reduce the initial response time of dual-heat-flux thermometer which measures body temperature in supine position, we employed the curve-fitting method to one subject. And thereby, we could obtain the deep body temperature in a minute. This result shows the possibility that the system can be used as practical temperature monitoring system with appropriate curve-fitting model. In the next study, we would try to establish a general fitting model that can be applied to all of the subjects. In addition, we are planning to extract meaningful health information such as sleep structure analysis from deep body temperature data which are acquired from this system.

Predictive factors for tuberculosis in patients with a TB-PCR-negative bronchial aspirate

PURPOSE

Pulmonary tuberculosis (PTB), with a tuberculosis (TB)-polymerase chain reaction (PCR)-negative bronchial aspirate (BA), but a positive culture result is often encountered in clinical practice. However, limited data are available concerning clinical judgment in patients with suspected PTB and a TB-PCR-negative BA pending culture results. The present study aimed to identify predictors for PTB in patients with a TB-PCR-negative BA.

METHODS

A retrospective study was conducted on patients who had undergone a bronchoscopy because of suspected PTB. Clinical, laboratory, and computed tomography (CT) findings were investigated in PTB patients with TB-PCR-negative but positive culture BA results, and non-PTB patients with a radiographic lesion comparable to the former.

RESULTS

Of 250 patients screened, 31 (12 %) were diagnosed with PTB by positive culture results only. Of these 31 patients, 30 (97 %) had a lesion within one-third of the hemithorax as determined by chest radiography. In the final analysis of 30 PTB and 65 non-PTB patients with comparable radiographic lesions, a positive QuantiFERON-TB Gold In-Tube (QFT) result was independently associated with an increased risk of a positive TB culture. CT findings of consolidation were a negative predictor for PTB. Patients with a negative QFT result and consolidation had a negative predictive value of 95 % for PTB, while patients with a positive QFT result and nodular CT abnormalities without consolidation had a positive predictive value of 86 % for PTB.

CONCLUSION

The simple combination of CT findings of consolidation and QFT test results may help clinicians to refine decision-making in patients with a TB-PCR-negative BA.

Fall detection algorithm for the elderly using acceleration sensors on the shoes

The rate of increase in the number of aging population in Korea is very rapid among OECD-member countries. And fall accident is one of the most common factors that threaten the health of the elderly. Therefore, it is needed to develop a fall detection system for the elderly. Most fall detection systems use accelerometers attached on the torso. And in various studies, it was verified that these systems have high sensitivity and high specificity. However, the elderly would feel uncomfortable when banding a sensor on the chest every day. Therefore, in this study, we attached an accelerometer on the shoes to detect fall in the elderly. This prototype system would be improved as a smaller, low-power system in the next study. Also, applying energy harvesting device to this shoe system is being developed to reduce the weight of battery.

MRI to differentiate benign from malignant soft-tissue tumours of the extremities: a simplified systematic imaging approach using depth, size and heterogeneity of signal intensity

OBJECTIVE

Differentiating between malignant and benign lesions on the basis of MR images depends on the experience of the radiologist. For non-experts, we aimed to develop a simplified systematic MRI approach that uses depth, size and heterogeneity on T(2) weighted MR images (T(2)WI) to differentiate between malignant and benign lesions, and evaluated its diagnostic accuracy.

METHODS

MR images of 266 patients with histologically proven soft-tissue tumours of the extremities (102 malignant, 164 benign) were analysed according to depth (superficial or deep), size (<50, ≥50 mm) and signal intensity (homogeneous or heterogeneous) on T(2)WI, to determine the ability of each to predict benign and malignant tumours. These three parameters were categorised into systematic combinations of different orders of application, and each combination was assessed for its ability to differentiate between benign and malignant lesions.

RESULTS

Univariate analysis showed that depth, size and heterogeneity on T(2)WI differed significantly between benign and malignant masses (p<0.0001 each). Multiple logistic regression analysis, however, showed that depth was not helpful in distinguishing benign from malignant lesions. The systematic combination of signal intensity, size and depth, in that order, was superior to other combinations, resulting in higher diagnostic values for malignancy, with a sensitivity of 64%, a specificity of 85%, a positive predictive value of 32%, a negative predictive value of 59% and an accuracy of 77%.

CONCLUSION

A simplified systematic imaging approach, in the order signal intensity, size and depth, would be a reference to distinguish between benign and malignant soft-tissue tumours for non-experts.

CT appearances of abdominal tuberculosis

The purpose of this article is to review and illustrate the spectrum of computed tomography (CT) appearances of abdominal tuberculosis. Tuberculosis can affect any organ or tissue in the abdomen, and can be mistaken for other inflammatory or neoplastic conditions. The most common sites of tuberculosis in the abdomen include lymph nodes, genitourinary tract, peritoneal cavity and gastrointestinal tract. The liver, spleen, biliary tract, pancreas and adrenals are rarely affected, but are more likely in HIV-seropositive patients and in miliary tuberculosis. This article should alert the radiologist to consider abdominal tuberculosis in the correct clinical setting to ensure timely diagnosis and enable appropriate treatment.

Aggravated capillary non-perfusion after intravitreal bevacizumab for macular edema secondary to systemic lupus erythematosus and anti-phospholipid syndrome

A 22-year-old female with history of systemic lupus erythematosus (SLE) was referred for evaluation of decreased visual acuity in her right eye. Her best-corrected visual acuity (BCVA) at the time of presentation was 20/160. Widespread cotton wool spots and macular edema were seen on biomicroscopy. Fluorescein angiography (FA) revealed retinal arterial and venous obstruction with capillary nonperfusion at the superotemporal retina. Antiphospholipid syndrome (APS) was diagnosed based on positive lupus anti-coagulant and ocular manifestations. Scattered laser photocoagulation was applied at the nonperfusion area but the visual acuity continued to deteriorate due to macular edema. Intravitreal bevacizumab (IVB) was administered for macular edema. One day after IVB, the BCVA decreased to count fingers. FA revealed extended non-perfusion from the superotemporal area to the posterior pole. Use of intravitreal bevacizumab for macular edema secondary to SLE or APS should be considered carefully and patients monitored closely for vascular complications.

An unusual cause of obstructive jaundice

Small-cell carcinomas of lung origin have been well characterised for their clinico-histopathological features. However, extrapulmonary small-cell carcinomas are rare, and in particular, they are extremely rare at the ampullary region. We report herein a case of small-cell carcinoma of ampulla of Vater and review its clinical, histological, and immunohistochemical features.

Colloid coalescence with focused x rays

We show direct evidence that focused x rays enable us to merge polymer colloidal particles at room temperature. This phenomenon is ascribed to the photochemical scission of colloids with x rays, reducing the molecular weight, glass transition temperature, surface tension, and viscosity of colloids. The observation of the neck bridge growth with time shows that the x-ray-induced colloid coalescence is analogous to viscoelastic coalescence. This finding suggests a feasible protocol of photonic nanofabrication by sintering or welding of polymers, without thermal damage, using x-ray photonics.

Hepatocarcinogenesis of regenerative and dysplastic nodules in Chinese patients

OBJECTIVES

To determine the development rate of hepatocellular carcinoma and survival of patients diagnosed to have regenerative, and low-grade and high-grade dysplastic liver nodules.

DESIGN

Retrospective descriptive study.

SETTING

Acute public hospital, Hong Kong.

PATIENTS

Patients with non-malignant liver nodules confirmed by imaging-guided liver biopsy between January 1997 and December 2008.

MAIN OUTCOME MEASURES

Rates of hepatocellular carcinoma development and survival.

RESULTS

A total of 147 patients with non-malignant liver nodules were followed up over a median duration of 29 months. The initial histological diagnosis included regenerative nodules (n=74), low-grade dysplastic nodules (n=34), and high-grade dysplastic nodules (n=39). The respective cumulative hepatocellular carcinoma development rate during the first, second, third, and fourth year were 3%, 5%, 9% and 12% for simple regenerative nodules, 29%, 35%, 38% and 44% for low-grade dysplastic nodules, and 38%, 41%, 51% and 51% for high-grade dysplastic nodules. The hepatocellular carcinoma development rate was highest in those with high-grade dysplastic nodules. Multivariate analysis showed that histological dysplastic changes were associated with increased alpha-fetoprotein levels and advanced age, which were both independent predictors of hepatocellular carcinoma development. Histological dysplastic changes, male sex, advanced age, prolonged prothrombin time, and ultrasound appearances were independent predictors of mortality.

CONCLUSION

The presence of dysplastic change in liver nodules increased the risk of hepatocellular carcinoma development and death.

Executive dysfunction and left frontal white matter hyperintensities are correlated with neuropsychiatric symptoms in stroke patients with confluent white matter hyperintensities

BACKGROUND/AIMS

This study aimed to determine the clinical and neuroimaging correlates of the presence of neuropsychiatric symptoms in stroke patients with age-related confluent white matter hyperintensities (WMH).

METHODS

The Neuropsychiatric Inventory was utilized to detect the presence of 12 symptoms. Multivariate logistic regression models were used to identify clinical and neuroimaging correlates of the presence of symptoms.

RESULTS

Seventy-seven stroke patients (mean WMH volume: 39.5 cm(3)) were recruited. Thirty patients (39%) had ≥ 1 neuropsychiatric symptom. Poor executive function was associated with the presence of any symptoms and symptoms other than depression. More severe left frontal WMH was associated with depression.

CONCLUSION

Executive dysfunction and left frontal WMH are correlated with neuropsychiatric symptoms in these patients.

Frequency of CYP2C9 variant alleles, including CYP2C9*13 in a Korean population and effect on glimepiride pharmacokinetics

WHAT IS KNOWN AND OBJECTIVE

Cytochrome P450 (CYP) 2C9 is a clinically important enzyme involved in the metabolism of many drugs commonly used in humans. Of several allelic variants known to affect the catalytic activity of the CYP2C9 enzyme, the frequencies of the CYP2C9*3 and CYP2C9*13 alleles in the Korean population have been reported as 1·1% and 0·6%, respectively. Our objective was to re-evaluate the frequencies of CYP2C9 allelic variants in the Korean population, including the CYP2C9*13 allele by pyrosequencing, and to investigate the pharmacokinetics of glimepiride in relation to CYP2C9 genotypes, including CYP2C9*3/*3.

METHODS

295 subjects were genotyped for CYP2C9*2 and CYP2C9*3 using the TaqMan procedure, and for CYP2C9*13 using pyrosequencing. These data were combined with our previously reported data to assess the CYP2C9 allele and genotype frequencies in 869 Korean subjects. Data from 24 of the 295 genotyped subjects (22 CYP2C9*1/*1 homozygotes, one CYP2C9*1/*3 heterozygote and one CYP2C9*3/*3 homozygote) who had participated in a bioequivalence study were analysed retrospectively to examine the effects of CYP2C9 genotype on glimepiride pharmacokinetics.

RESULTS

The frequencies of the CYP2C9*1/*3, *3/*3, and *1/*13 genotypes in the study population (n = 295) were 0·081 (n = 24), 0·010 (n = 3) and 0·003 (n = 1), respectively. In the 869 subjects from the combined studies, allele frequencies for CYP2C9*3 and CYP2C9*13 were 0·025 (95% CI: 0·018, 0·033) and 0·002 (95% CI: 0·000, 0·010), respectively. Relative to CYP2C9*1 homozygotes, the one CYP2C9*3 homozygous subject was found to have a higher AUC(0-∞) value (490% of the reference value) and a lower oral clearance rate (18% of the reference).

WHAT IS NEW AND CONCLUSION

This study is the first examination of CYP2C9*3 homozygotes in the Korean population. Our data on the one subject with this genotype suggest that CYP2C9*3/*3 momozygotes have lower clearance of glimepiride and are exposed to higher levels of the drug than wild-type homozygotes. Although we identified a subject with the CYP2C9*13 allele using a new pyrosequencing assay, we were unfortunately unable to investigate its effects on glimepiride pharmacokinetics.

Operational definitions improve reliability of the age-related white matter changes scale

BACKGROUND AND PURPOSE

Although the age-related white matter changes (ARWMC) scale has been advocated to be applicable to both MRI and CT for assessing the severity of WMC, its inter-rater reliability on CT is only fair. We aimed to operationalize the ARWMC scale and investigate the effect of this operationalization on the reliability and validity on MRI and CT.

METHODS

Operational definitions of the ARWMC scale were derived from Erkinjuntti research criteria for subcortical vascular dementia and Scheltens scale. Using original and operationalized ARWMC scale, eight observers recorded the time for rating per MRI and per CT. We investigated the inter-rater and intrarater reliability as well as validity against volume using data from 97 stroke patients.

RESULTS

Inter-rater reliability of the operationalized scale on CT (0.874, 95% confidence interval [0.780-0.934]) was better than the original scale (0.569, 95% confidence interval [0.247-0.775]). Its intrarater reliability on CT (0.869) and reliability on MRI (inter-rater: 0.860; intrarater: 0.838) was comparable with the original scale (CT intrarater: 0.750 and on MRI inter-rater: 0.845; intrarater: 0.853). The time required to administer the operationalized scale (4'2″ for MRI and 1'18″ for CT) was similar to that of the original scale (3'56″ for MRI and 1'16″ for CT). The original scale and operationalized scale also significantly correlated with WMC volume (operationalized scale ρ = 0.613, P < 0.001, original scale ρ = 0.638, P < 0.001).

CONCLUSION

Operational definitions improve the inter-rater reliability of ARWMC scale on CT, and it correlates with volumetric measurement.

Isolation and characterization of bacteriocin-producing bacteria from the gastrointestinal tract of broiler chickens for probiotic use

AIMS

To isolate and characterize the bacteriocin-producing bacteria (BPB) from the gastrointestinal tract of broiler chickens for probiotic use.

METHODS AND RESULTS

In total, 291 bacterial strains were isolated from broilers and screened for bacteriocin-producing ability. The bacteriocins produced by Enterococcus faecium SH 528, Ent. faecium SH 632 and Pediococcus pentosaceus SH 740 displayed inhibitory activity against pathogens including Clostridium perfringens and Listeria monocytogenes. Activity of the bacteriocins remained unchanged after 30 min of heat treatment at 60 degrees C or exposure to organic solvents, but diminished after treatment with proteolytic enzymes. PCR was used to detect the structural genes enterocin A and B in SH 528, enterocin L50 and P in SH 632, and pediocin PA-1 in SH 740. Most of them were resistant to 0.5% bile salts and remained viable after 2 h at pH 3.0. Ent. faecium SH 528 exhibited the highest amylase activity among the strains tested.

CONCLUSIONS

We selected Ent. faecium SH 528 and SH 632 and Ped. pentosaceus SH 740 by probiotic selection criteria including inhibition activity against pathogens.

SIGNIFICANCE AND IMPACT OF THE STUDY

The isolated BPB could potentially be used in the poultry industry as probiotics to control pathogens.

Direct comparison of optical frequency combs using a comb-injection-lock technique

This paper demonstrates a direct comparison of optical frequency combs (OFCs) with different repetition rates without a stable intermediate laser using a single-mode comb-injection-lock technique. Two OFCs based on Ti:Sapphire mode-locked lasers were compared utilizing a single-mode diode laser for the selection and the amplification of one mode of an OFC by comb-injection, which makes the direct comb comparison possible. The frequencies of the two combs were found to agree within 0.019 Hz at 352 THz with the uncertainty of 0.25 Hz (7.1 x 10(-16) ). This is one of the best results among the comparisons of combs referenced to a microwave frequency. This technique simplifies the comb comparison utilities and can be applied even when repetition rates differ.

Isolation and partial characterization of a bacteriocin produced by Pediococcus pentosaceus K23-2 isolated from Kimchi

AIMS

Screening and partial characterization of a bacteriocin produced by Pediococcus pentosaceus K23-2 isolated from Kimchi, a traditional Korean fermented vegetable.

METHODS AND RESULTS

A total of 1000 lactic acid bacteria were isolated from various Kimchi samples and screened for the production of bacteriocin. Pediocin K23-2, a bacteriocin produced by the Pediococcus pentosaceus K23-2 strain, showed strong inhibitory activity against Listeria monocytogenes. The bacteriocin activity remained unchanged after 15 min of heat treatment at 121 degrees C or exposure to organic solvents; however, it diminished after treatment with proteolytic enzymes. The bacteriocin was maximally produced at 37 degrees C, when the pH of the culture broth was maintained at 5.0 during the fermentation, although the optimum pH for growth was 7.0. The molecular weight of the bacteriocin was about 5 kDa according to a tricine SDS-PAGE analysis.

CONCLUSIONS

Pediococcus pentosaceus K23-2 isolated from Kimchi produces a bacteriocin, which shares similar characteristics to the Class IIa bacteriocins. The bacteriocin is heat stable and shows wide antimicrobial activity against Gram-positive bacteria, especially L. monocytogenes.

SIGNIFICANCE AND IMPACT OF THE STUDY

Pediocin K23-2 and pediocin K23-2-producing P. pentosaceus K23-2 could potentially be used in the food and feed industries as natural biopreservatives, and for probiotic application to humans or livestock.

Polymorphisms in the type IV collagen alpha3 gene and the risk of COPD

A number of genome-wide linkage analyses have identified the 2q33.3-2q37.2 region as the most likely to contain the genes that contribute to the susceptibility to chronic obstructive pulmonary disease (COPD). It was hypothesised that the type IV collagen alpha3 (COL4A3) gene, which is one of the genes located in the 2q33.3-2q37.2 region, may act as a low-penetrance susceptibility gene for COPD. To test this hypothesis, the association of COL4A3 -1162T>C, IVS2+12C>A, P141L, G162E, H451R, P574L and *315C>A polymorphisms with the risk of COPD was investigated in a case-control study of 311 COPD patients and 386 controls. The presence of at least one 451R allele was associated with a significantly higher risk of COPD compared with the 451 H/H genotype (adjusted odds ratio 1.48, 95% confidence interval (1.03-2.14)). When the subjects were stratified according to age and COPD severity, the 451R allele was associated with a significantly higher risk of COPD only in younger individuals with severe COPD (3.02 (1.37-6.67)). In conclusion, these findings suggest that the type IV collagen alpha3 gene contributes to the genetic susceptibility to chronic obstructive pulmonary disease.

Cell cycle arrest and lytic induction of EBV-transformed B lymphoblastoid cells by a histone deacetylase inhibitor, Trichostatin A

Latent infection of the Epstein-Barr virus (EBV) is strongly associated with the pathogenesis of several human tumor types. The restricted expression of the latent EBV antigens is critical for EBV-associated tumors to escape from immune surveillance. EBV lytic replication can be triggered by various treatments and the induced lytic genes cause strong cytotoxic T lymphocyte (CTL) responses. Histone acetylation or deacetylation is associated with chromatin remodeling and regulates gene expression. Histone deacetylase (HDAC) inhibitors affect cell cycle progression as well as gene expression in a wide variety of transformed cells. We examined whether an HDAC inhibitor, TSA, can affect cell cycle progression and induce EBV lytic replication in EBV-transformed lymphoblastoid cell lines (LCLs). TSA caused cell cycle arrest at low concentrations and induced apoptosis at higher (>300 nM) concentrations in the LCLs and EBV negative BJAB cells. To clarify the underlying mechanism of TSA-induced cell cycle arrest, expression of cell cycle regulatory factors was examined by RNase protection assay and Western blot analysis. Following TSA treatment, a reduced expression of cyclin D2 and an induction of p21 may have played an essential role for G1 arrest in LCLs, while p21 induction might have arrested BJAB cells in G1 phase. A Cdk inhibitor, p57, was increased by 300 nM TSA in both LCLs and BJAB cells, indicating its role in apoptosis. Moreover, immunofluorescene assay and Western blotting showed that TSA induced EBV lytic replication in LCL cells. These results suggest that TSA may exert an enhanced anti-tumor effect for EBV-associated tumors not only by inducing a cell cycle arrest and apoptosis, but also by triggering an EBV lytic cycle.

Ginsenoside Rh2 is one of the active principles of Panax ginseng root to improve insulin sensitivity in fructose-rich chow-fed rats

Ginsenoside Rh2, one of the ginsenosides contained in the Panax ginseng root, was employed to screen the effect on insulin resistance of rats induced by a diet containing 60% fructose. Single intravenous injection of ginsenoside Rh2 decreased the plasma glucose concentrations in 60 minutes in a dose-dependent manner from 0.1 mg/kg to 1 mg/kg in rats with insulin resistance induced by fructose-rich chow. Repeated intravenous injection of ginsenoside Rh2 (1 mg/kg per injection, 3 times daily) into rats which received fructose-rich chow for 3 consecutive days decreased the value of glucose-insulin index, the product of the areas under the curve of glucose and insulin during the intraperitoneal (i.p.) glucose tolerance test. This means that ginsenoside Rh2 has an ability to improve insulin action on glucose disposal. The plasma glucose lowering action of tolbutamide, induced by the secretion of endogenous insulin, is widely used to characterize the formation of insulin resistance. Time for the loss of plasma glucose lowering response to tolbutamide (10 mg/kg, i.p.) in rats during insulin resistance induction by fructose-rich chow was also markedly delayed by the repeated treatment of ginsenoside Rh2, as compared to the vehicle-treated control. Thus, the repeated treatment of ginsenoside Rh2 delayed the development of insulin resistance in high fructose feeding rats. Increase of insulin sensitivity by ginsenoside Rh2 was further identified using the plasma glucose lowering action of exogenous insulin in streptozotocin-induced diabetic rats (STZ-diabetic rats). Repeated injection of ginsenoside Rh2 at the same dosing (1 mg/kg, 3 times daily) into STZ-diabetic rats for 10 days made an increase of the responses to exogenous insulin. Taken together, it can be concluded that ginsenoside Rh2 has an ability to improve insulin sensitivity and it seems suitable to use ginsenoside Rh2 as an adjuvant for diabetic patients and/or the subjects wishing to increase insulin sensitivity.

Functional outcome of the hand following flexor tendon repair at the 'no man's land'

PURPOSE

To evaluate the functional outcome of the hand following flexor tendon repair at 'no man's land' using 2 strands of a modified Kessler core suture and combined controlled motion rehabilitation protocol.

METHODS

Records of 31 zone-2 flexor tendon injuries in 21 digits of 16 patients between July 2000 and June 2005 were reviewed retrospectively. The injured tendons were repaired within 24 hours using 2 strands of a modified Kessler core suture, reinforced by a continuous circumferential epitendon suture. All patients completed a rehabilitation protocol that included active extension against a rubber band, passive flexion, and controlled passive extension and passive flexion exercises. Functional outcome of the fingers was assessed using the Buck-Gramcko II score. Hand grip strength, rehabilitation period, and rupture rate were also measured.

RESULTS

17 (81%) out of 21 digits in 15 out of 16 patients achieved an excellent-to-good functional grade. The remaining patient with concomitant injuries to 4 (19%) digits attained a poor functional grade, attributable to poor compliance with the rehabilitation protocol. The mean rehabilitation period was 130 days and the mean grip strength was 78% that of the uninjured side. Concomitant digital nerve injury did not adversely affect the final outcome. Only one (4.8%) patient experienced a rupture.

CONCLUSION

The surgical method and rehabilitation protocol used for zone-2 flexor tendon injury is safe and results in a reasonably good functional outcome.

Importance in optimization of multi-slice computed tomography scan protocols

This paper reviews the reasons why multi-slice CT scanners may give patients higher dose than their single-slice predecessors and discusses the type of optimization of multi-slice scan protocols that may be undertaken to keep patient doses to acceptable levels without compromising image quality. It also provides estimates of patient effective dose values and dose length products for typical procedures and briefly discusses the implication that these dose values have for the induction of possible stochastic effects.