[The association between Helicobacter pylori virulence factor genotypes and gastroduodenal diseases in children]

Objective: To investigate the association between Helicobacter pylori (Hp) virulence factor genotypes and the degree and activity of gastric mucosa pathological changes in pediatric gastroduodenal diseases. Methods: This retrospective cohort study was conducted from May 2020 to October 2020. The frozen strains of Hp, which were cultured with the gastric mucosa of 68 children with gastroscopy confirmed gastroduodenal diseases who visited the children's hospital of Zhejiang University School of Medicine from April 2012 to December 2014, were resuscitated. After extracting DNA from these Hp strains, PCR amplification and agarose gel electrophoresis were performed to determine the detection rate of cytotoxin-associated protein A (cagA),vacuolating cytotoxin A (vacA)(s1a、s1b/s2,m1/m2), outer inflammatory protein A (oipA),blood group antigen binding adhesin (babA),duodenal ulcer promoting protein A (dupA) genes; oipA genes were sequenced to determine the gene status. The patients were divided into different groups according to the findings of gastroscopy and gastric mucosa pathology. The detection rates of various virulence factor genotypes among different groups were compared using χ2 tests or Fisher's exact tests. Results: The 68 Hp strains all completed genetic testing. According to the diagnostic findings of gastroscopy, the 68 cases were divided into 47 cases of superficial gastritis and 21 cases of peptic ulcer. Regarding the pathological changes of gastric mucosa, 8 cases were mild, and 60 cases were moderate and severe according to the degree of inflammation; 61 cases were active and 7 cases inactive according to the activity of inflammation. The overall detection rates of cagA, vacA, vacA s1/m2, functional oipA, babA2, and dupA virulence factor genes were 100% (68/68), 100% (68/68), 94% (64/68), 99% (67/68), 82% (56/68), and 71% (48/68), respectively. In the superficial gastritis group, their detection rates were 100% (47/47), 100% (47/47), 96% (45/47), 98% (46/47), 81% (38/47), and 70% (33/47), respectively; in the peptic ulcer group, their detection rates were 100% (21/21), 100% (21/21), 90% (19/21), 100% (21/21), 86% (18/21), and 71% (15/21), respectively. There was no statistically significant difference between the two groups (all P>0.05). In the mild gastric mucosa inflammation group, the detection rates of the above six genotypes were 8/8, 8/8, 8/8, 7/8, 7/8, and 5/8, respectively; and in the moderate to severe inflammation groups, the detection rates were 100% (60/60), 100% (60/60), 93% (56/60), 100% (60/60), 82% (49/60), and 72% (43/60), respectively, with no statistically significant difference between the two groups (all P>0.05). In the active inflammation group, the detection rate of six genotypes were 100% (61/61), 100% (61/61), 93% (57/61), 98% (60/61), 82% (50/61), and 72% (44/61), respectively; and in the inactive inflammation group, they were 7/7, 7/7, 7/7, 7/7, 6/7, and 4/7, respectively. Again, there was no statistically significant difference between the two groups (all P>0.05). There was no statistically significant difference in the detection rate of combinations of 4 or 5 virulence factor genes among the different groups (all P>0.05). Conclusions: CagA, vacA, vacA s1/m2, functional oipA, babA2, and dupA genes are not associated with superficial gastritis and peptic ulcer in children, or with the degree and activity of gastric mucosa pathological inflammation. Different gene combinations of cagA, vacA, oipA, babA2, and dupA have no significant effects on predicting the clinical outcome of Hp infection in children.

[The relationship between genetic polymorphism of CYP2C19 and the efficacy of Helicobacter pylori eradication therapy in children]

Objective: To investigate the relationship between genetic polymorphisms of cytochrome P450 2C19 (CYP2C19) and the efficacy of Helicobacter pylori (Hp) eradication therapy in children. Methods: The retrospective cohort study was conducted on 125 children with gastroscopy and positive rapid urease test (RUT) from September 2016 to December 2018 who presented to the Children's Hospital of Zhejiang University School of Medicine due to gastrointestinal symptoms including nausea, vomiting, abdominal pain, bloating, acid reflux, heartburn, chest pain, vomiting blood and melena. Hp culture and drug susceptibility test were carried out with gastric antrum mucosa before treatment. All the patients completed 2 weeks of standardized Hp eradication therapy and had ¹³C urea breath test 1 month after that, which was used to evaluate the curative effect. The DNA of gastric mucosa after RUT was analyzed and CYP2C19 gene polymorphism was detected. Children were grouped according to metabolic type. Combined with the results of Hp culture and drug susceptibility, the relationship between CYP2C19 gene polymorphism and the efficacy of Hp eradicative treatment was analyzed in children. Chi square test was used for row and column variables, and Fisher exact test was used for comparison between groups. Results: One hundred and twenty five children were enrolled in the study, of whom 76 were males and 49 females. The genetic polymorphism of CYP2C19 in these children found poor metabolizer (PM) of 30.4% (38/125), intermediate metabolizer (IM) of 20.8% (26/125), normal metabolizer (NM) of 47.2% (59/125), rapid metabolizer (RM) of 1.6% (2/125), and ultrarapid metabolizer (UM) of 0. There were statistically significant in positive rate of Hp culture among these groups (χ²=124.00, P<0.001). In addition, the successful rates of Hp eradication in PM, IM, NM and RM genotypes were 84.2% (32/38), 53.8% (14/26), 67.8% (40/59), and 0, respectively, with significant differences (χ²=11.35, P=0.010); those in IM genotype was significantly lower than that in PM genotype (P=0.011). With the same standard triple Hp eradicative regimen, the successful rate of Hp eradication for IM type was 8/19, which was lower than that of PM (80.0%, 24/30) and NM type (77.3%, 34/44) (P=0.007 and 0.007, respectively). There was a significant difference in the efficacy of Hp eradication treatment among different genotypes (χ²=9.72, P=0.008). According to the clarithromycin susceptibility result, the successful rate of Hp eradication treatment for IM genotype was 4/15 in the sensitive group and 4/4 in the drug-resistant group (χ²=6.97, P=0.018). Conclusions: The genetic polymorphism of CYP2C19 in children is closely related to the efficacy of Hp eradication treatment. PM has a higher successful rate of eradication treatment than the other genotypes.

Circ_0020256 induces fibroblast activation to drive cholangiocarcinoma development via recruitment of EIF4A3 protein to stabilize KLF4 mRNA

Cancer-associated fibroblasts (CAFs) are a kind of stromal cells in the cholangiocarcinoma (CCA) microenvironment, playing crucial roles in cancer development. However, the potential mechanisms of the interaction between CCA cells and CAFs remain obscure. This work investigated the role of circ_0020256 in CAFs activation. We proved circ_0020256 was up-regulated in CCA. High circ_0020256 expression facilitated TGF-β1 secretion from CCA cells, which activated CAFs via the phosphorylation of Smad2/3. Mechanistically, circ_0020256 recruited EIF4A3 protein to stabilize KLF4 mRNA and upregulate its expression, then KLF4 bound to TGF-β1 promoter and induced its transcription in CCA cells. KLF4 overexpression abrogated the inhibition of circ_0020256 silencing in TGF-β1/Smad2/3-induced CAFs activation. Furthermore, CCA cell growth, migration, and epithelial-mesenchymal transition were favored by CAFs-secreted IL-6 via autophagy inhibition. We also found circ_0020256 accelerated CCA tumor growth in vivo. In conclusion, circ_0020256 promoted fibroblast activation to facilitate CCA progression via EIF4A3/KLF4 pathway, providing a potential intervention for CCA progression.

Immunogenic cell death-associated biomarkers classification predicts prognosis and immunotherapy efficacy in pancreatic ductal adenocarcinoma

Introduction

Immunogenic cell death (ICD) is a sort of regulated cell death (RCD) sufficient to trigger an adaptive immunological response. According to the current findings, ICD has the capacity to alter the tumor immune microenvironment by generating danger signals or damage-associated molecular patterns (DAMPs), which may contribute in immunotherapy. It would be beneficial to develop ICD-related biomarkers that classify individuals depending on how well they respond to ICD immunotherapy.

Methods and results

We used consensus clustering to identify two ICD-related groupings. The ICD-high subtype was associated with favorable clinical outcomes, significant immune cell infiltration, and powerful immune response signaling activity. In addition, we developed and validated an ICD-related prognostic model for PDAC survival based on the tumor immune microenvironment. We also collected clinical and pathological data from 48 patients with PDAC, and patients with high EIF2A expression had a poor prognosis. Finally, based on ICD signatures, we developed a novel PDAC categorization method. This categorization had significant clinical implications for determining prognosis and immunotherapy.

Conclusion

Our work emphasizes the connections between ICD subtype variations and alterations in the immune tumor microenvironment in PDAC. These findings may help the immune therapy-based therapies for patients with PDAC. We also created and validated an ICD-related prognostic signature, which had a substantial impact on estimating patients' overall survival times (OS).

AB1426 PREDICTORS OF RHEUMATIC TOXICITIES OF IMMUNE CHECKPOINT INHIBITORS AND CANCER OUTCOMES IN PATIENTS WITH ADVANCED MELANOMA

Background

Immune checkpoint inhibitors (ICIs) including monoclonal antibodies to PD-1 and CTLA-4 have activity across various cancers. Dedicated cohort studies have examined the epidemiology and clinical course of rheumatic toxicities (1–3) and the effect of pre-existing autoimmune disease has been explored (4), with limited assessment of the effect of non-immune mediated rheumatic disease (3). A positive association between ICI-induced rheumatic disease and favourable cancer outcomes has been suggested (1,2), although derived from heterogenous cancer populations.

Objectives

To identify risk factors for the development of ICI-induced rheumatic disease and predictors of cancer outcomes in patients with advanced melanoma.

Methods

A single-centre observational study of patients with stage III or IV melanoma receiving all available ICI therapies, who completed a for-purpose questionnaire to capture rheumatic symptoms and risk factors upon recruitment and at 12-months. Symptom severity was assessed according to patient reported measures such as visual analogue scale (VAS) scores for pain. Clinical details were extracted from patients’ medical records. Predictors of rheumatic toxicities and cancer outcomes were identified through regression analysis.

Results

Amongst 147 eligible patients, the prevalence of new or worsening rheumatic symptoms was 32.5% at recruitment and 21% at 12 months. The incidence of documented arthralgia, inflammatory arthritis and PMR-like syndrome was 39.5%, 5.4% and 3.4% respectively. Binary logistic regression identified pre-existing symptomatic rheumatic disease, including non-immune mediated rheumatic disease, as the primary risk factor for developing rheumatic toxicities (OR 3.161). Continuation of ICI therapy (OR 16.52), followed by rheumatic toxicities (OR = 4.368) were predictors of favourable tumour response.

Conclusion

Rheumatic toxicities of ICI therapy commonly affect patients with melanoma and are more likely to occur in patients with pre-existing autoimmune and non-immune mediated rheumatic disease. Continuation of ICI therapy improves cancer outcomes and can be facilitated by early detection of rheumatic symptoms using patient reported outcome measures.

Table 1.

Bivariate logistic regression of predictors of patient-reported rheumatic toxicity. Sig., Significance; OR, Odds ratio; CI, confidence interval; BRAF/MEK, BRAF and MEK inhibitors; PD-1, Programmed Cell Death protein – 1; CTLA-4, Cytotoxic T-lymphocyte-associated protein.

Figure 1.

A) Receiver-operator curve for accuracy of binary logistic regression model clinician-recorded rheumatic disease. (B) Area under receiver-operator curve. Test result variable(s): predicted probability. AUROC, Area Under Receiver-Operator Curve; Std. Error, Standard Error; Sig., Significance.

(a) Under the nonparametric assumption

(b) Null hypothesis: true area = 0.5

References

[1]Kostine M, Rouxel L, Barnetche T, Veillon R, Martin F, Dutriaux C, et al. Rheumatic disorders associated with immune checkpoint inhibitors in patients with cancer-clinical aspects and relationship with tumour response: a single-centre prospective cohort study. Ann Rheum Dis. 2018;77(3):393–8.

[2]Braaten TJ, Brahmer JR, Forde PM, Le D, Lipson EJ, Naidoo J, et al. Immune checkpoint inhibitor-induced inflammatory arthritis persists after immunotherapy cessation. Ann Rheum Dis. 2019;332–8.

[3]Buder-Bakhaya K, Benesova K, Schulz C, Anwar H, Dimitrakopoulou-Strauss A, Weber TF, et al. Characterization of arthralgia induced by PD-1 antibody treatment in patients with metastasized cutaneous malignancies. Cancer Immunol Immunother. 2018;67(2):175–82.

[4]Menzies AM, Johnson DB, Ramanujam S, Atkinson VG, Wong ANM, Park JJ, et al. Anti-PD-1 therapy in patients with advanced melanoma and preexisting autoimmune disorders or major toxicity with ipilimumab. Ann Oncol. 2017;28(2):368–76.

Disclosure of Interests

Alana Bruce: None declared, Alexander Menzies Consultant of: A.M.M. has participated in advisory boards for BMS, MSD, Novartis, Roche, Pierre-Fabre, Georgina Long Consultant of: GVL is consultant advisor for Aduro Biotech Inc, Agenus Inc, Amgen Inc, Array Biopharma inc, Boehringer Ingelheim International GmbH, Bristol-Myers Squibb, Evaxion Biotech A/S, Hexel AG, Highlight Therapeutics S.L., Merck Sharpe & Dohme, Novartis Pharma AG, OncoSec, Pierre Fabre, QBiotics Group Limited, Regeneron Pharmaceuticals Inc, Specialised Therapeutics Australia Pty Ltd., Brian Fernandes: None declared, Fredrick Joshua Consultant of: F.J. has performed clinical trials and participated in advisory boards for Abbvie, Pfizer, Novartis, Sanofi, Eli Lily and Roche

Giant recurrent left inguinal hernia with femoral nerve injury: a report of a rare case

Background

Giant inguinal hernia(GIH), a rare disease, has brought great challenges to surgeons. GIH is defined as an inguinal hernia that extends below the midpoint of the inner thigh in standing position. However, a giant recurrent inguinal hernia resulting from previous operations that destroy the anatomical structure of the inguinal region is extremely rare. Nerve injury, a complication following inguinal hernia repair, is mostly found in ilioinguinal nerve and iliohypogastric nerve, which often presents as numbness and acute or chronic pain, while postoperative muscular dysfunction results from femoral nerve injury is rare.

Case presentation

A 77-years-old woman presented with a complaint of a reducible mass in the left inguinal of duration 1 year. The patient had three previous inguinal hernia repairs. Physical examination and auxiliary examination indicated a giant inguinal hernia with femoral nerve injury. After preoperative evaluation and preparation, a transabdominal partial extraperitoneal(TAPE) repair have performed. Finally, the patient recovered and was discharged.

Conclusions

In conclusion, we reported a rare case of a giant recurrent inguinal hernia with femoral nerve injury and made a successful treatment for the patient via transabdominal partial extraperitoneal(TAPE) repair.

Observation of A Raman mode splitting in few layer black phosphorus encapsulated with hexagonal boron nitride

We investigate the impact of encapsulation with hexagonal boron nitride (h-BN) on the Raman spectrum of few layer black phosphorus. The encapsulation results in a significant reduction of the line width of the Raman modes of black phosphorus, due to a reduced phonon scattering rate. We observe a so far elusive peak in the Raman spectra ∼4 cm^-1 above the A mode in trilayer and thicker flakes, which had not been observed experimentally. The newly observed mode originates from the strong black phosphorus inter-layer interaction, which induces a hardening of the surface atom vibration with respect to the corresponding modes of the inner layers. The observation of this mode suggests a significant impact of h-BN encapsulation on the properties of black phosphorus and can serve as an indicator of the quality of its surface.

Paediatric CT dose: a multicentre audit of subspecialty practice in Australia and New Zealand

OBJECTIVES

To evaluate paediatric CT dosimetry in Australia and New Zealand and calculate size-specific dose estimates (SSDEs) for chest and abdominal examinations.

METHODS

Eight hospitals provided data from 12 CT systems for 1462 CTs in children aged 0-15. Imaging data were recorded for eight examinations: head (trauma, shunt), temporal bone, paranasal sinuses, chest (mass) and chest HRCT (high-resolution CT), and abdomen/pelvis (mass/inflammation). Dose data for cranial examinations were categorised by age and SSDEs by lateral dimension. Diagnostic reference ranges (DRRs) were defined by the 25th and 75th percentiles. Centralised image quality assessment was not undertaken.

RESULTS

DRRs for 201 abdominopelvic SSDEs were: 2.8-4.7, 3.6-11.5, 8.5-15.0, 7.6-15, and 10.6-16.2 for the <15 cm, 15-19 cm, 20-24 cm, 25-29 cm and >30 cm groups, respectively. For 147 chest examinations using these body width categories, SSDE DRRs were 2.0-4.4, 3.3-7.9, 4.0-9.4, 4.5-12, and 6.5-12. Kilovoltage peak (kVp), but not AEC or IR, was associated with SSDE (parameter estimate [standard error]: 0.12 (0.03); p < 0.0001).

CONCLUSIONS

Australian and New Zealand paediatric CT DRRs and abdominal SSDEs are comparable to international data. SSDEs for chest examinations are proposed. Dose variations could be reduced by adjusting kVp.

KEY POINTS

• SSDEs can be calculated for all patients, CT systems, and practices • Kilovoltage peak (kVp) has the greatest association with dose in similar-sized patients • Paediatric DRRs for CT are now available for use internationally.

Wearing a crotch strap on a correctly fitted lifejacket improves lifejacket performance

Wearing a lifejacket when immersed in water should support the wearer, maintaining their airway clear of the water. It is proposed that a retention system would improve airway protection by improving retention of the lifejacket around the torso. Study one (n = 10) quantified the performance of lifejackets immediately following a step into water from height when a lifejacket was worn with a crotch strap (two different tightness) and without a crotch strap. Airway freeboard was improved when wearing a crotch strap (P < 0.05) compared with no crotch strap. Study two used a manikin to examine the performance of lifejackets with and without a crotch strap during 3-h exposures to waves. During exposure to waves, the time taken to aspirate the lethal dose of seawater for drowning was doubled when wearing a crotch strap compared with the no-crotch-strap conditions (P < 0.001). Therefore, wearing a crotch strap (functioning retention system) on a correctly fitted lifejacket improves airway protection following accidental immersion and prolonged wave exposure.

Histological and finite element analysis of cell death due to irreversible electroporation

Irreversible electroporation (IRE) has been shown to be an effective method of killing cells locally. In contrast to radiofrequency ablation, the mechanism by which cells are thought to die via IRE is the creation of pores in cell membranes, without substantial increase in tissue temperature. To determine the degree to which cell death is non-thermal, we evaluated IRE in porcine hepatocytes in vivo. Using pulse widths of 10μs, bursts of 3 kV square-wave pulses were applied through a custom probe to the liver of an anesthetized pig. Affected tissue was evaluated histologically via stainings of hematoxylin & eosin (H&E), nitroblue tetrazolium (NBT) to monitor cell respiration and TUNEL to gauge apoptosis. Temperature was measured during the application of electroporation, and heat transfer was modeled via finite element analysis. Cell death was calculated via Arrhenius kinetics. Four distinct zones were observed within the ring return electrode; heat-fixed tissue, coagulation, necrotic, and viable. The Arrhenius damage integral estimated complete cell death only in the first zone, where the temperature exceeded 70°C, and partial or no cell death in the other zones, where maximum temperature was approximately 45°C. Except for a limited area near the electrode tip, cell death in IRE is predominantly due to a non-thermal mechanism.

CathCam guide wire-directed colonoscopy: first pilot study in patients with a previous incomplete colonoscopy

BACKGROUND AND STUDY AIMS

Conventional colonoscopy as the gold standard for large-bowel diagnostics and therapy may fail in 5 %-20 % of cases, depending on the experience of the examiner. Colonoscopy is regarded as difficult and painful by many patients. In an attempt to overcome the limitations of conventional colonoscopes, a guide wire-directed, thin, flexible diagnostic colonoscope, the CathCam was developed. In this prospective pilot study, we report its use in patients in whom conventional colonoscopy had failed.

PATIENTS AND METHODS

49 patients with a previous or current failure of complete colonoscopy were invited to participate in a trial using the new CathCam system, and 14 (nine men; mean age 59 years) accepted. The CathCam is an 11-mm diameter disposable, multilumen catheter, with visualization by a 3-mm camera with six light-emitting diodes. In the first five patients, the CathCam was inserted over a newly developed 0.024-inch, hinged, lumen-seeking guide wire. Subsequently, a modified combined approach was used: a conventional colonoscope was introduced into the sigmoid or left colon, then the guide wire was advanced as far as possible, followed by CathCam insertion over it. Caecal intubation rate, insertion times and patient discomfort were recorded; patients received low-dose midazolam sedation (2-5 mg).

RESULTS

One patient was excluded during colonoscopy. The caecum could be eventually reached in 12 of 13 patients; in the remaining patient a significant sigmoid stricture could be passed, but further advancement appeared too risky. The mean caecal intubation time was 24 minutes (range 3-105 min). Only two patients experienced pain and discomfort during the procedure (one immediate assessment and one case reported at later telephone interview). No complications occurred, and previously undiagnosed important findings were obtained in 9 cases.

CONCLUSIONS

A combined approach, consisting of guide wire insertion via a partially introduced colonoscope followed by CathCam or colonoscope insertion into the caecum was successful in over 90 % of patients with previous failure of complete colonoscopy. Further improvements may make this system suitable for use as a standard diagnostic colonoscope, either as a single unit (CathCam plus guide wire) or using the guide wire alone with a standard colonoscope in difficult cases.

Right internal carotid pseudoaneurysm mimicking a retropharyngeal abscess in a child

A 7-year-old girl with tonsillar infection with antibiotics. Two weeks later, there was a right sided neck lump. Computed tomography scans demonstrated a predominantly hypodense right retropharyngeal area with peripheral enhancement and mass effect. There was intense enhancement within the postero-superior aspect of the lesion which was continuous with the right internal carotid artery. Ultrasound demonstrated tapering of the right internal carotid artery. Magnetic resonance imaging and magnetic resonance arteriography showed a right internal carotid artery pseudoaneurysm. Surgical exploration confirmed the finding. This case highlights an unusual presentation of an internal carotid pseudoaneurysm and how imaging provided the diagnosis.

Temperature trends in total hip arthroplasty: a retrospective study

The purpose of this study was to define the temporal trend in body temperature of patients during the first 5 days after total hip arthroplasty (THA). The medical records of 98 consecutive THAs were reviewed, 88 clinically uncomplicated cases were included. The average maximum temperature reached during the study period was 38.08 degrees C, a 3.7% (P< or =.01) increase from the preoperative base line of 36.64 degrees C. In this study, 62.5% of patients reached a temperature > or =38.0 degrees C; 19.3% > or = 38.5 degrees C; and 3.4% > or = 39.0 degrees C. No patients had a preoperative temperature of > or =38 degrees C recorded. On the first postoperative day, 39 patients had a temperature > or =38 degrees C. The number of febrile patients progressively decreased until by the fifth postoperative day, only 5 patients had a temperature > or =38 degrees C recorded.

Chloroform: exposure estimation, hazard characterization, and exposure-response analysis

Chloroform has been assessed as a Priority Substance under the Canadian Environmental Protection Act. The general population in Canada is exposed to chloroform principally through inhalation of indoor air, particularly during showering, and through ingestion of tap water. Data on concentrations of chloroform in various media were sufficient to serve as the basis for development of deterministic and probabilistic estimates of exposure for the general population in Canada. On the basis of data acquired principally in studies in experimental animals, chloroform causes hepatic and renal tumors in mice and renal tumors in rats. The weight of evidence indicates that chloroform is likely carcinogenic only at concentrations that induce the obligatory precursor lesions of cytotoxicity and proliferative regenerative response. Since this cytotoxicity is primarily related to rates of formation of reactive, oxidative metabolites, dose response has been characterized in the context of rates of formation of reactive metabolites in the target tissue. Results presented here are from a "hybrid" physiologically based pharmacokinetic (PBPK) animal model that was revised to permit its extension to humans. The relevant measure of exposure response, namely, the mean rate of metabolism in humans associated with a 5% increase in tumor risk (TC05), was estimated on the basis of this PBPK model and compared with tissue dose measures resulting from 24-h multimedia exposure scenarios for Canadians based on midpoint and 95th percentiles for concentrations in outdoor air, indoor air, air in the shower compartment, air in the bathroom after showering, tap water, and food. Nonneoplastic effects observed most consistently at lowest concentrations or doses following repeated exposures of rats and mice to chloroform are cytotoxicity and regenerative proliferation. As for cancer, target organs are the liver and kidney. In addition, chloroform has induced nasal lesions in rats and mice exposed by both inhalation and ingestion at lowest concentrations or doses. The mean rate of metabolism associated with a 5% increase in fatty cysts estimated on the basis of the PBPK model was compared with tissue dose measures resulting from the scenarios already described, and lowest concentrations reported to induce cellular proliferation in the nasal cavities of rats and mice were compared directly with midpoint and 95th percentile estimates of concentrations of chloroform in indoor air in Canada. The degree of confidence in the underlying database and uncertainties in estimates of exposure and in characterization of hazard and dose response are delineated.

Volumetric model determination of the tibia based on 2D radiographs using a 2D/3D database

We present a new concept with mathematical background for the construction of a three-dimensional (3D) volumetric model of the human tibia based on two conventional orthogonal two-dimensional (2D) radiographic images. This approach is supported by a computer database containing a collection of 80 2D/3D image data sets of individual cadaveric tibiae. For each of these tibiae, the database contains digitized 2D orthogonal radiographic images in both anterior and lateral views, and the corresponding 3D CT data obtained by computerized tomography. To obtain a 3D model of a tibia for a given patient, shape matching is performed. The computer finds the most similar tibia to the patient's tibia among the 2D radiographic images in the database by applying a matching process. To improve accuracy, a 2D image warping procedure can be applied on the slices of the selected bone prior to 3D reconstruction. The warping process is controlled by the contour data of the two orthogonal views. We found that the 3D model thus achieved was useful for virtual preoperative planning and for simulation of the internal fixation of long bones.

[The significance of nucleotide repeat sequences in FVIII gene for detecting hemophilia A carriers]

OBJECTIVE

To detect the carriers in hemophilia A(HA) families by haplotype analysis of the microsatellite polymorphisms at intron 13 [13(CA)n] and 22[22(GT)n(AG)n] in the factor VIII (FVIII) gene.

METHOD

Multi-PCR amplification of 13(CA)n and 22(GT)n(AG)n combined with silver staining were used.

RESULTS

In 35 HA families, 11 had HA history. There were 21 female members in the 11 HA families and all of them were subjected to molecular study. Fourteen of the 21 females were confirmed to be carriers and approximately 72.7%(8 of 11) of these families were informative.

CONCLUSIONS

Besides the reliable detection of HA carriers, multi-PCR combined with silver staining in HA analysis has the advantages of time saving, simplicity for performing and no radiation contamination.

Antibacterial agents based on the cyclic D,L-alpha-peptide architecture

The rapid emergence of bacterial infections that are resistant to many drugs underscores the need for new therapeutic agents. Here we report that six- and eight-residue cyclic d,l-alpha-peptides act preferentially on Gram-positive and/or Gram-negative bacterial membranes compared to mammalian cells, increase membrane permeability, collapse transmembrane ion potentials, and cause rapid cell death. The effectiveness of this class of materials as selective antibacterial agents is highlighted by the high efficacy observed against lethal methicillin-resistant Staphylococcus aureus infections in mice. Cyclic d,l-alpha-peptides are proteolytically stable, easy to synthesize, and can be derived from a potentially vast membrane-active sequence space. The unique abiotic structure of the cyclic peptides and their quick bactericidal action may also contribute to limit temporal acquirement of drug resistant bacteria. The low molecular weight d,l-alpha-peptides offer an attractive complement to the current arsenal of naturally derived antibiotics, and hold considerable potential in combating a variety of existing and emerging infectious diseases.

Isolated ventricular septal defect secondary to low-velocity blunt chest trauma

Damage to the ventricular septum resulting from low velocity blunt trauma to the anterior chest wall is a rarely reported disorder. We wish to report a case of an isolated large ventricular septal defect secondary to blunt chest trauma requiring urgent surgical repair in an otherWise healthy 19 year old male. The patient endured a long hospital stay complicated by repeated episodes of pulmonary oedema and ARDS but eventually made a good recovery.

Documentation of in-training assessment for radiology trainees

AIM

To determine if the assessment of radiology trainees can be improved by modifying the in-training assessment form issued by the Royal College of Radiologists (RCR).

MATERIALS AND METHODS

A qualitative study comparing the RCR assessment form with other alternative forms in use in the U.K. Individual semi-structured interviews were conducted with trainees (21) and trainers (18) in Sheffield to collect their views on the RCR form and an alternative form introduced on the North Trent Training Scheme. A postal questionnaire was sent to Heads of Training (24) to find out what assessment forms were in use at other centres and collect their views on the different forms.

RESULTS

Trainees and trainers in Sheffield were virtually unanimous in their support of the new North Trent assessment form. The main advantages perceived were the encouragement of appraisal, setting of objectives and feedback from the trainees. Six other radiology training centres were using alternative assessment forms and all believed their forms had advantages over the RCR in-training assessment form.

CONCLUSION

The results of this study suggest that the assessment process for radiology trainees can be improved by modifications to the RCR in-training assessment form and allows various recommendations to be made.

[Separation and enrichment of fetal nucleated red blood cells from maternal blood for non-invasive prenatal gene diagnosis]

OBJECTIVE

In order to develop a non-invasive technique for prenatal gene diagnosis.

METHODS

Peripheral blood mononuclear cells (MNCs) were separated by single density gradient Histopaque 1.077 from 25 pregnant women with gestations between 8 - 36 weeks. The fetal nucleated red blood cells (NRBCs) were enriched from the MNCs by positive selection using Dynabeads M-450 CD(71) or negative selection using Dynabeads M-450 CD(45). The enriched NRBCs were identified by anti-gamma-biotin or anti-zeta-biotin antibodies. Globin gene of NRBCs from fetuses with risk of beta-thalassemia major were amplified with nested PCR followed by reverse dot blot hybridization for gene diagnosis.

RESULTS

NRBCs stained by anti-gamma-biotin or anti-zeta-biotin antibodies could be found in the peripheral blood samples of the 25 pregnant women. Three out of 5 fetuses with risk of beta-thalassemia major were successfully diagnosed using these NRBCs.

CONCLUSION

Fetal NRBCs in maternal circulation can be isolated and enriched by single gradient density Histopaque 1.077 followed by magnetic activated cell sorting. Nested PCR can amplify DNA for gene diagnosis from no less than 20 NRBCs.

[Linkage analysis of the G6PD gene mutations and its Nla III polymorphic site]

OBJECTIVE

To investigate the molecular and anthropologic features of glucose-6-phosphate dehydrogenase (G6PD) deficiency and the linkage between the Nla III polymorphic site within G6PD gene and three common Chinese G6PD mutations.

METHODS

By using denatured gradient gel electrophoresis (DGGE) and allele specific oligonucleotide (ASO) probe dot blot hybridization, Nla III polymorphic site at minus sign13 bp upstream exon 12 within G6PD gene were screened in 54 males with normal G6PD activity and 66 G6PD deficient males.

RESULTS

Thirty-two cases with cDNA1376 (G-->T), 21 with cDNA1388 (G-->A) and 13 with cDNA95 (A-->G) were detected in the 66 G6PD deficient males. Among 54 normal controls, T at -13 bp upstream exon 12 within G6PD gene were detected in 11 cases (20.4%, without Nla III polymorphic sites) while C in 43 cases (79.6%, with Nla III polymorphic sites). All 66 G6PD deficient males were linked with C at -13 bp upstream exon 12 (with Nla III polymorphic sites).

CONCLUSION

The G6PD mutations cDNA1376 (G-->T), cDNA1388 (G-->A) and cDNA95 (A-->G) were linked with Nla III polymorphism. This feature will play a role in studying the complicated manifestations and anthropology of G6PD deficiency.

Analysis of 1,076 cases of sexual assault

STUDY OBJECTIVE

Rates of sexual assault are increasing, and evidence exists that its demographics and characteristics are changing. The purpose of our study was to describe victim, assailant, assault, and treatment characteristics for sexual assault victims and to provide descriptive data on the evidentiary examination.

METHODS

Prospective data were collected on all sexual assault victims presenting to an urban Level I trauma center from January 1992 to December 1995 for treatment and evidentiary examination. Data from crime laboratory records were retrospectively reviewed.

RESULTS

One thousand one hundred twelve patients presented after a sexual assault. A total of 1,076 (97%) patients consented to the medical and evidentiary examination and were enrolled in the study. Age ranged from 1 to 85 years (mean, 25 years; median, 23 years), with 96% (1,036/1,076) female and 4% (41/1,076) male victims. The number of assailants was greater than 1 in 20% (208/1,044) of cases, and the assailant was a stranger only 39% (409/1,094) of the time. Force was used in 80% (817/1,027) of reported assaults, and in 27% (275/1,014) of cases a weapon was present. Vaginal intercourse was involved in 83% (851/1,023) of female victims. Oral assault was involved in 25% (271/1,053) of all cases, and anal penetration was involved in 17% (178/1,058) of all cases. Overall, general body trauma was seen 67% (621/927) of the time, and genital trauma occurred in 53% (388/736) of cases. Twenty percent (147/1,712) of patients had no trauma noted on examination. Sperm were noted on the emergency department wet mount in only 13% (93/716) of the victims, and of the 612 cases with both ED sperm data and crime laboratory semen data available, evidence of sperm and semen were found 48% (296/612) of the time by either.

CONCLUSION

Health care professionals should be aware that general body trauma is common, that the assailant is often someone known to the victim, and that evidence of semen is commonly found by the crime laboratory even when it is not found in the ED analysis of a wet mount.

The relationship between teacher sign skills and student evaluations of teacher capability

This study examines the extent to which deaf students' perceptions of their teachers' effectiveness and ease of communication in the classroom are related to the teachers' sign skills. Thirty-three faculty, teaching a variety of courses at the National Technical Institute for the Deaf (NTID), were rated on "teaching effectiveness" and "communication ease" by their students over a 2-year period. Faculty sign proficiency was evaluated independently using the Sign Communication Proficiency Interview (SCPI). Results indicate a moderate relation between students' perceptions of communication ease and teaching effectiveness, and a weak relation of these two variables to the teachers' assessed level of sign skill. The data also show that the students could clearly differentiate three levels of teacher sign skill in the classroom. Results are discussed in relation to the component parts of effective communication from the perspective of students in the classroom.

Magnetic resonance imaging of injuries in the child athlete

Sports related injuries in children and adolescents are an increasingly frequent clinical problem. Soft tissue injury is relatively less common in children than in adults and radiographs suffice in most situations. However there are specific clinical circumstances where MR imaging is of value. We discuss and demonstrate a variety of acute and chronic sports related conditions where MR imaging has contributed to the diagnosis and management. Some conditions such as apophysitis, osteochondritis and chronic physeal injuries are unique to childhood while others including spondylysis and stress fractures are unusual conditions outside the context of sport in this age group.

Familiarity and pronounceability of nouns and names

Ratings of familiarity and pronounceability were obtained from a random sample of 199 surnames (selected from over 80,000 entries in the Purdue University phone book) and 199 nouns (from the Kucera-Francis, 1967, word database). The distributions of ratings for nouns versus names are substantially different: Nouns were rated as more familiar and easier to pronounce than surnames. Frequency and familiarity were more closely related in the proper name pool than the word pool, although both correlations were modest. Ratings of familiarity and pronounceability were highly related for both groups. A production experiment showed that rated pronounceability was highly related to the time taken to produce a name. These data confirm the common belief that there are differences in the statistical and distributional properties of words as compared to proper names. The value of using frequency and the ratings of familiarity and pronounceability for predicting variations in actual pronunciations of words and names are discussed.