Exploration of AI-Assisted On-Board Perfusion Imaging Technique on Patients Undergoing Thoraxradiotherapy

PURPOSE/OBJECTIVE(S)

Pulmonary function of lung cancer patients can significantly change along the radiation therapy (RT) course. Scholars have synthesized lung function maps from computed tomography (CT) images. Still, there is lack of study exploring the feasibility of generating lung perfusion information from cone-beam CT (CBCT). Our study aims to fill up this gap in the body of literatures.

MATERIALS/METHODS

One-hundred-and-six pairs of planning CT and CBCT images of thoracic cancer patients from XX hospital were collected retrospectively. All CT images were registered to CBCT with a deformable algorithm, and referred as deformed planning CT (dCT). A 2D convolutional neural network (CNN) model built with cycle generative adversarial network (cycle-GAN) was trained to correct CBCT image artifacts and HU value discrepancies. The corrected CBCT was named enhanced CBCT (eCBCT) in this study. All CBCT, eCBCT and dCT images were then input to a pre-trained CT-to-perfusion deep learning (DL) model to synthesize perfusion images (PI), namely PICBCT, PIeCBCT and PIdCT respectively. For model training, 80 image pairs were assigned to the training set while others to the testing set. dCT and PIdCT were respectively regarded as the ground truth in two consecutive models. One extra validation case acquired with SPECT perfusion scan was collected for model performance test. Quantitative evaluation was done between the ground truth and the synthesized images. Peak signal-to-noise ratio (PSNR) and mean absolute error (MAE) were computed to assess efficacy of CBCT enhancement. Correlation (R) and Dice similarity coefficient (DSC) were used to evaluate voxel-wise and function-wise concurrence in CBCT-derived perfusion mapping.

RESULTS

In CBCT enhancement, [eCBCT-dCT] pairs demonstrated higher agreement than [CBCT-dCT] pairs. Quantitatively, PSNR and MAE were improved from 21.10±1.60 to 24.08±1.76, and 68.99±13.51 to 47.06±11.31 (p<0.01), respectively. For perfusion translation, higher correlation was demonstrated in both voxel-wise and function-wise evaluation within [PIeCBCT-PIdCT] than [PICBCT-PIdCT]. R correlation increased from 0.84±0.09 to 0.89±0.06 (p<0.01), whereas DSC in high-functional regions increased from 0.77±0.06 to 0.82±0.05 (p<0.01). In the validation case, strong correlation was observed between SPECT perfusion scan and PIeCBCT, with R increasing from 0.57 to 0.65 when compared to PICBCT.

CONCLUSION

We proposed a novel DL framework that synthesized perfusion images from fractionally acquired CBCT. Our framework met the clinical needs in providing real-time lung perfusion maps. It can be used to track the continuously changing pulmonary function status throughout the RT course using routinely scanned CBCT, without additional imaging modalities. The framework can facilitate functionally guided adaptive radiation therapy by providing immediate pulmonary function information.

Dedifferentiated endometrioid adenocarcinoma of the uterus: A case series and review of literature

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Dedifferentiated endometrioid adenocarcinoma is a rare aggressive subtype of endometrial cancer.

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Patients tend to present at a later stage and have early recurrences.

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Proportion of DEAC in endometrial cancer may affect outcome.

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Further research should focus on PD-L1 expression and the use immunotherapy.

Introduction Dedifferentiated endometrioid adenocarcinoma (DEAC) was first described in 2007. However, it has only been recognised as a distinct subtype of endometrioid adenocarcinoma in the last 1–2 years. DEAC is a more aggressive histological subtype and carries a poorer prognosis. Patients with DEAC tend to present with advanced disease compared the other endometrioid adenocarcinomas. Methodology The study is a retrospective review of patients with DEAC diagnosed in two institutions in Singapore between January 2012 and October 2017. Results 7 patients were diagnosed with DEAC. The mean age was 56.4 years. All patients presented with either abnormal uterine bleeding or post menopausal bleeding. Out of the 7 patients, one was diagnosed with Stage 2 disease, 5 were diagnosed with Stage 3 disease and 1 was diagnosed with Stage 4 disease. One patient had neoadjuvant chemotherapy, followed by surgery, and completion chemotherapy post surgery. The other 6 patients (87.5%) underwent primary debulking surgery. Out of these 6 patients, 5 patients had adjuvant chemotherapy post surgery and one patient had both adjuvant chemotherapy and radiotherapy. Lymphovascular invasion was found in 71.4% of the cases. Conclusion DEAC is a more aggressive histological subtype of endometrioid adenocarcinomas. Better awareness of this condition can lead to proper diagnosis and treatment.

Prognostic factors associated with clear cell sarcoma in 14 Chinese patients

PURPOSE. To identify prognostic factors associated with clear cell sarcomas in 14 Chinese patients. METHODS. Medical records of 7 men and 7 women (mean age, 36 years) with histologically confirmed clear cell sarcoma of tendons and aponeuroses were reviewed. Patient demographics, tumour characteristics, and treatment modalities were retrieved. Prognostic factors associated with favourable 5-year survival were determined. RESULTS. The most affected sites were the thigh (n=5) and the foot (n=4); the mean time from symptom onset to diagnosis was 9.5 months. The tumour stage at diagnosis was IIA in 8 patients, IIB in 2, and III in 4. The mean tumour size was 4.5 cm in diameter. One patient was lost to follow-up. For the remaining 13 patients, the mean time to disease-related mortality was 2.5 years. Nine patients had distant metastases; the most common sites were lungs and pleura (n=7), followed by distant lymph nodes (n=4), bone (n=2), pericardium (n=2), and brain (n=1). All patients underwent surgical excision. Three women and one man (mean age, 27 years) attained 5-year disease-free survival. All had stage IIA tumours at diagnosis. Their mean tumour size was 1.75 cm in diameter, which was significantly smaller than that of all patients (4.5 cm). Tumour size of ≤ 2.5 cm in diameter (p=0.004) and stage IIA tumour at diagnosis (p=0.04) were significant prognostic factors for 5-year survival. CONCLUSION. Tumour size of ≤ 2.5 cm and early stage tumour are associated with 5-year disease-free survival. Early detection is crucial for the prognosis of clear cell sarcomas.

Transferred WT1-reactive CD8+ T cells can mediate antileukemic activity and persist in post-transplant patients

Relapse remains a leading cause of death after allogeneic hematopoietic cell transplantation (HCT) for patients with high-risk leukemias. The potentially beneficial donor T cell-mediated graft-versus-leukemia (GVL) effect is often mitigated by concurrent graft-versus-host disease (GVHD). Providing T cells that can selectively target Wilms tumor antigen 1 (WT1), a transcription factor overexpressed in leukemias that contributes to the malignant phenotype, represents an opportunity to promote antileukemic activity without inducing GVHD. HLA-A*0201-restricted WT1-specific donor-derived CD8 cytotoxic T cell (CTL) clones were administered after HCT to 11 relapsed or high-risk leukemia patients without evidence of on-target toxicity. The last four treated patients received CTL clones generated with exposure to interleukin-21 (IL-21) to prolong in vivo CTL survival, because IL-21 can limit terminal differentiation of antigen-specific T cells generated in vitro. Transferred cells exhibited direct evidence of antileukemic activity in two patients: a transient response in one patient with advanced progressive disease and the induction of a prolonged remission in a patient with minimal residual disease (MRD). Additionally, three treated patients at high risk for relapse after HCT survive without leukemia relapse, GVHD, or additional antileukemic treatment. CTLs generated in the presence of IL-21, which were transferred in these latter three patients and the patient with MRD, all remained detectable long-term and maintained or acquired in vivo phenotypic and functional characteristics associated with long-lived memory CD8 T cells. This study supports expanding efforts to immunologically target WT1 and provides insights into the requirements necessary to establish potent persistent T cell responses.

Asymptomatic grade-2 central chondrosarcoma of the distal femur with non-aggressive radiological features

This paper discusses the case of a 57-year-old man with an incidental finding of a radiologically non-aggressive chondroid lesion and concomitant osteonecrosis in the left distal femur. The final resected specimen showed a grade-2 chondrosarcoma. This case illustrates that long-term follow-up is necessary for non-aggressive chondroid lesions. If surgical management is considered, resection with an adequate margin is superior to intralesional curettage.

A sarcoma of 23 years' duration: symptom duration is not a reliable parameter to exclude malignancy

This report describes a 31-year-old woman with a 23-year history of a right buttock mass that was otherwise asymptomatic, but was proven to be a low-grade fibromyxoid sarcoma (a fully malignant soft tissue tumour with a potential for distant metastasis). This case illustrates that a long-standing tumour does not necessarily imply a benign pathology. A vigilant approach should be taken for any tumours that are of significant size (larger than 5 cm).

Neuroimaging techniques in epilepsy

OBJECTIVE

To review state-of-the-art neuroimaging modalities in epilepsy and their clinical applications.

DATA SOURCES AND STUDY SELECTION

PubMed literature searches to March 2010, using the following key words: 'epilepsy', 'positron emission tomography (PET)', 'single photon emission computed tomography (SPECT)', 'MR volumetry', 'diffusion tensor imaging', and 'functional MR imaging'.

DATA EXTRACTION

All articles including neuroimaging techniques in epilepsy were included in the review.

DATA SYNTHESIS

High-field magnetic resonance imaging is fundamental for high-resolution structural imaging. Functional radionuclide imaging (positron emission tomography/single-photon emission computed tomography) can provide additional information to improve overall accuracy, and show good results with high concordance rates in temporal lobe epilepsy. Magnetic resonance spectroscopy is a useful adjunct consistently demonstrating changing metabolites in the epileptogenic region. Magnetic resonance volumetric imaging shows excellent sensitivity and specificity for temporal lobe epilepsy but thus far it has been inconsistent for extratemporal epilepsy. Diffusion tensor imaging with tractography allows visualisation of specific tracts such as connections with the language and visual cortex to enhance preoperative evaluation. Functional magnetic resonance imaging using blood oxygen level-dependent activation techniques is mainly used in presurgical planning for the high-sensitivity mapping of the eloquent cortex. Both contrast-bolus and arterial spin labelling magnetic resonance perfusion imaging show good correlation with clinical lateralisation of seizure disorder.

CONCLUSION

Structural imaging is essential in localisation and lateralisation of the seizure focus. Functional radionuclide imaging or advanced magnetic resonance imaging techniques can provide complementary information when an epileptogenic substrate is not identified or in the presence of non-concordant clinical and structural findings.

Characteristics and photocatalytic activity of TiO2 thin film sensitized with a porphyrin dye

In this study, a novel porphyrin dye, 5, 10, 15, 20-tetraphenyl-21H, 23H-porphine nickel (TPPN) doped TiO2 (TiO2/TPPN) thin film with visible light respondency was prepared using a sol-gel method and characterized with XRD, SEM, UV-Vis instruments. The observation showed that the absorption edge of TPPN dye-doped thin film shifted into the visible light region. The photocatalytic indigo carmine degradation results showed that under visible light irradiation (lambda > 400 nm) for 6 hrs, the photocatalytic activity of TiO2 thin film sensitized with 200 microM of TPPN dye showed the best performance, with an indigo degradation ratio up to 96%. Moreover, the TiO2/TPPN thin film showed a relevant photocatalytic bactericidal effect on Erwinia carotovora subsp. carotovora 7 induced vegetable soft rot disease in the visible spectral region. Evidence for the photocatalytic disinfection technique against a plant pathogen under visible light irradiation will have potential for direct application in future control of plant diseases in irrigation water systems.

Patient effective dose from sentinel lymph node lymphoscintigraphy in breast cancer: a study using a female humanoid phantom and thermoluminescent dosemeters

The aim of this study was to measure the dose delivered to patients undergoing sentinel lymph node lymphoscintigraphy by taking into account both the transmission scan dose using a (57)Co flood source and the (99)Tc(m) internal emission dose. An adult female humanoid phantom and a set of thermoluminescent dosimeters were used in the measurements. The choice of measurement organs in the humanoid was guided by the recommendations described in the International Commission on Radiological Protection report number 60. A (57)Co flood source was used in external transmission to irradiate the humanoid at posterior, left lateral, left posterior oblique, right lateral and right posterior oblique positions. Four (99)Tc(m) deposits as internal emission sources were used to simulate patient peritumoural injection. The individual effective doses for external transmission and internal emission, normalized to the cumulated activity and expressed in micro Sv(MBq x h)(-1) were then calculated. The effective dose for a transmission scan was on average 0.061 micro Sv(MBq x h)(-1) for each (57)Co flood source position and for internal emission 0.312 micro Sv(MBq x h)(-1) and 0.291 micro Sv(MBq x h)(-1) for left and right breast injection, respectively. Using these results, the effective dose from both transmission and emission sources can be calculated according to the nuclear medicine scanning protocol and surgical procedure of the individual institution. For our protocols, the patient receives a maximum effective dose of 52 micro Sv for the 1 day protocol (18 MBq injection) and 204 micro Sv for the 2 day protocol (74 MBq injection) if only the sentinel lymph node is excised. If other tissues containing radioactivity are removed, the patient effective dose will be reduced by about 50% and 6%, respectively, for the 1 day protocol and 2 day protocol. Although the doses are low compared with other radiological examinations, the results are informative for patients concerned about radiation exposure for this new imaging technique.

Glove punctures in orthopaedic surgery

From February 2001 to May 2001, 792 latex gloves used in 100 operations from three orthopaedic sub-specialties (paediatrics, hand and spine) were tested for puncture by a water infusion test. Sixty-nine gloves from 45 operations were punctured, giving an overall glove perforation rate of 8.7% (69/792) and an operative perforation rate of 45% (45/100). The hand operations had the lowest operative perforation rate (19.4%) while the spine operations had the highest (63.6%). The glove perforation rate increased in bony procedures (60% versus 22.5%), in procedures with major instrumentation (66% versus 18%) and in more lengthy procedures. The thumbs and the left index finger had more punctures than other parts. In addition, the glove perforation rate for single gloving was 9.6% (53/552) while that for the inner glove of double gloving was 0.8% (1/120). Based on these findings, we would like to recommend double gloving and regular glove changing in these high-risk surgeries.

Lateral temporal hyperperfusion in postictal psychosis assessed by 99mTc-HMPAO SPECT

Postictal psychosis is a rare complication of epileptic seizure characterized by reversible psychotic symptoms after flurries of seizure attack. It has been attributed to a phenomenon similar to Todd's paralysis without definitive proof. We studied regional cerebral blood flow (rCBF) of six patients with postictal psychosis by (99m)Tc-HMPAO SPECT scan. Baseline rCBF was compared with the rCBF during postictal psychosis. An asymmetry index (ASI) was calculated as 200 x [(ipsilateral ROI count density - contralateral ROI count density)/(ipsilateral ROI count density + contralateral ROI count density)] %. Significant differences could be found between ASIs during postictal psychosis and interictal state SPECT scan over the lateral temporal neocortex region (P = 0.017). Although hyperperfusion abnormality in SPECT can be found in Todd's paralysis, such findings are more commonly found in cerebral hyperactivity conditions. Taking into account the clinical characteristics of postictal psychosis, namely a preceding lucid interval and crescendo-decrescendo clinical course, these may be an alternative psychopathogenic mechanism for the development of postictal psychosis.

The performance of three vacuum-mixing cement guns--a comparison of the fatigue properties of simplex P cement

We tested three commercially available cement-mixing systems (Howmedica, Summit and Stryker). After mixing the cement was allowed to cure in metal moulds under standard conditions. Sixty-nine cement blocks were produced. The fatigue behavior of the blocks was tested until failure. A wide scattering of results was observed in all the three systems. Uneven mixing of the polymer and monomer was observed in the Howmedica system. A significantly stronger cement (P=0.018) was produced with the Stryker system.

Cementless total hip arthroplasty in young Chinese patients: a comparison of 2 different prostheses

Sixty-one primary cementless total hip arthroplasties were performed in 45 Chinese patients <40 years old. There were 27 Anatomic Medullary Locking (AML, Depuy, Warsaw, IN) prostheses and 34 Porous Coated Anatomic (PCA, Howmedica, Rutherford, NJ) prostheses. The average follow-up was 7.6 years (range, 3-11 years). Ten hips (16%) were reoperated; the reason was polyethylene wear with or without osteolysis in 7 hips. Osteolytic lesion was present in 34 hips (56%). The cumulative successful rate at 10 years was 67% using reoperation for any reason as the endpoint. The cumulative successful rate was 98%, however, if revision for aseptic loosening was used as the endpoint. The 2 prostheses did not show significant differences in most parameters except that the PCA hips had significantly more acetabular loosening (P =.02) and periprosthetic osteolysis (P =.01).

Charnley total hip arthroplasty in Chinese patients less than 40 years old

Forty-seven total hip arthroplasties were reviewed in 33 Chinese patients who were <40 years old at the time of operation. The preoperative diagnosis was avascular necrosis in 40% of the hips. A Charnley prosthesis was inserted using early cementing techniques in every hip. The average follow-up was 14.9 years (range, 6.9-21.1 years). The mean preoperative Harris hip score was 43.8 (range, 26-74), and the mean score at latest follow-up was 87.7 (range, 74-99) for the surviving hips. Thirty hips (63%) were revised, and 1 hip was removed because of late deep infection. The main cause of failure was aseptic loosening of the acetabular component. Using revision and radiologic loosening as endpoints, the cumulative survival rate for the acetabular component was 86.3% at 10 years and 27.0% at 15 years. The survival of the femoral components was 81.3% at 15 years. Patients with avascular necrosis had a higher failure rate than patients with other diagnoses (P =.001). An area of cement mantle that was <2 mm thick affected adversely the survival rate of the acetabular components (P =.04).

A five-year longitudinal study of the regional cerebral metabolic changes of a schizophrenic patient from the first episode using Tc-99m HMPAO SPECT

This is a naturalistic study of the relationship between cerebral metabolic activity, clinical symptoms and treatment response in a schizophrenic patient for 5 years from the onset of her illness. Serial technetium-99m-HMPAO brain SPECT was used to measure regional cerebral metabolism. The Cambridge Neurological Inventory and neuropsychological tests (WAIS-R verbal subscales, Wisconsin Card Sorting Test, semantic verbal fluency, logical memory in Weschler Memory Scale) were used for neurocognitive assessment. Under-activity of the left temporal area was observed in the course of patient illness despite remission of the psychotic symptoms. Bilateral prefrontal metabolic under-activity was noted at the emergence of negative symptoms, executive neurocognitive dysfunction and the treatment-resistant state. After response to clozapine, the right prefrontal activity returned to a normal level. Our findings suggested that persistent left temporal underactivity detected by SPECT despite clinical remission may indicate a vulnerability for further relapses and development of a treatment-resistant state. Treatment-resistant state, negative symptoms and executive neurocognitive deficit may involve abnormal prefrontal metabolic activity and can be alleviated in clozapine-responsive patients.

Construction and preliminary characterization of a library of "lethal" preterminal protein mutant adenoviruses

Adenoviruses containing lethal in-frame insertion mutant alleles of the preterminal protein (pTP) gene were constructed with cell lines that express pTP. Thirty in-frame insertion mutant alleles, including 26 alleles previously characterized as lethal and 4 newly constructed mutant alleles, were introduced into the viral chromosome in place of the wild-type pTP gene. The viruses were tested for ability to form plaques at 37 degrees C in HeLa-pTP cells and at 32 degrees C and 39.5 degrees C in HeLa cells. Two of the newly constructed viruses exhibited temperature sensitivity for plaque formation, one virus did not form plaques in the absence of complementation, seven additional mutants exhibited a greater than 10-fold reduction in plaque formation in the absence of complementation, and another eight mutants exhibited stronger phenotypes than did previously characterized in-frame insertion mutants in the plaque assay. These mutant viruses offer promise for analysis of pTP functions.

Transient bone marrow oedema: a variant pattern of sacral insufficiency fractures

A 71-year-old woman presenting with severe low back pain was found to have a large oval area of increased sacral uptake on Tc-99m MDP scan, with corresponding T1-hypointense and T2-hyperintense areas on magnetic resonance (MR) images, highly suggestive of malignancy. Open biopsies showed only callus formation. The patient responded clinically to conservative measures, with twice-repeated follow-up Tc-99m MDP and MR scans documenting resolution of transient bone marrow oedema. We suggest that this form of marrow oedema represents a variant pattern of sacral insufficiency fractures.

Thromboelastographic study of thrombosis in the implantable central venous access device

BACKGROUND

In the present study thromboelastography (TEG) was to study whether or not hypercoagulopathy might contribute to the thrombosis of implantable central venous access device (Port-A-Cath, Pharmacia) in cancer patients.

METHODS

All 76 oncological patients who were enrolled in this study had their R time, alpha angle and MA value measured before Port-A-Cath implantation, of whom 11 patients received re-implantation because of thrombotic device. We compared the measurements of these 11 patients (thrombotic group) with that of 65 patients (control group) who received Port-A-Cath implantation for the first time. According to TEG values the hemostatic status in these patients was classified as hypercoagulable, normal or hypocoagulable for comparison. All patients in the control group were followed up for 3 months for occurrence of thrombosis.

RESULTS

It was found that no patient in the thrombotic group was associated with hypercoagulopathy. Five patients (7.5%) in the control group was found in hypercoagulable status at the time of catheter insertion but none of them developed clinical thrombosis during three months of observation. There was no significant difference between the two groups for R time, alpha angle but a higher MA value was found in the control group (p < 0.05). Furthermore, the hypercoagulability (7.5% for the control vs. none for the thrombotic group), hypocoagulability (1.5% vs. 9.1%) and normocoagulability (91.0% vs. 90.9%) were not statistically different between the two groups (Fisher exact test, P = 0.229).

CONCLUSIONS

We conclude that hypercoagulopathy in cancer patients has little, if any, contribution in thrombosis of the implantable central venous access device.

A range of CD4 T cell tolerance: partial inactivation to organ-specific antigen allows nondestructive thyroiditis or insulitis

T cell receptor (TCR) transgenic mice specific for hen egg lysozyme (HEL) were crossed with mice expressing HEL on the thyroid epithelium, on pancreatic islet beta cells, or systemically. Depending on the pattern of HEL expression, deletion of double-positive thymocytes ranged from minimal to complete, and peripheral CD4 cells exhibited graded reduction in TCR expression, in vitro responsiveness, and in vivo helper ability. CD4 cells were least tolerant in TCR/thyroid-HEL and TCR/islet-HEL mice, which developed an extensive lymphocytic thyroiditis or insulitis that nevertheless did not eliminate HEL-expressing endocrine cells. Autoreactive CD4 clones thus escape the thymus under a range of circumstances, retain sufficient function to initiate subclinical autoimmune inflammation when self-antigens are concentrated in the thyroid or pancreas, and may regulate progression of subclinical inflammation to destructive autoimmune disease.

Applications of bone scintigraphy in ankylosing spondylitis

Eighteen bone scintisans performed in 14 patients with ankylosing spondylitis were reviewed. In young patients with low back pain, positive serology, and indeterminate radiographs, quantitative sacroiliac joint assessment and the presence of typical uptake patterns, particularly costovertebral, were useful in suggesting the diagnosis. Scintigraphy was helpful in the early detection of pseudoarthrosis complicating long-standing disease, especially in patients presenting with recurrent back pain. Selective application of bone scintigraphy aids the diagnosis of ankylosing spondylitis and its potential complications.

Imaging of pelvic insufficiency fractures

Insufficiency fractures of the pelvis are being increasingly recognized as a major cause of low back pain in elderly women with osteoporosis. Fractures in the sacrum are difficult to diagnose, as plain radiographic findings are either unhelpful or misleading. Bone scintigraphy is very sensitive for the detection of fractures in the sacrum, with demonstration of the H-shaped (or butterfly) sacral pattern or the combination of concomitant sacral and parasymphyseal uptake being considered as characteristic of insufficiency fractures. Computed tomography (CT) is helpful for confirming the presence of fractures in cases with atypical scintigraphic patterns, particularly in those with a known primary malignant neoplasm. CT is especially useful in the further evaluation of parasymphyseal and pubic rami lesions. The majority of patients respond well to periods of enforced bed rest and administration of analgesics. Recognition of the spectrum of imaging findings for this entity should lead to its correct identification and the institution of appropriate treatment.

CD95 (Fas)-dependent elimination of self-reactive B cells upon interaction with CD4+ T cells

The recessive mouse mutations lpr and gld create deficiencies in an interacting pair of cell surface molecules, CD95 (Fas/APO-1) and Fas-ligand (FasL), respectively, resulting in autoantibody production resembling human systemic lupus erythematosus. The mechanisms of self-tolerance affected by deficiency in either molecule are not established, but CD95 deficiency both in B cells and in CD4+ T cells recognizing major histocompatibility complex (MHC) class II molecules is required for autoimmunity in lpr mice. Here we track the outcome of in vivo interactions between B cells and CD4+ T cells that recognize a transgene-encoded autoantigen, hen egg lysozyme (HEL), using cells from mice transgenic for immunoglobulin and T-cell receptor (TCR) genes. B cells that had not previously encountered HEL autoantigen (naive cells) were triggered into proliferation and antibody production upon interaction with antigen and HEL-specific CD4+ T cells. By contrast, B cells that had been chronically exposed to HEL during their development and carried desensitized surface immunoglobulin (sIg) antigen receptors (anergic cells) did not produce antibody but instead were eliminated in the presence of HEL-specific CD4+ T cells. CD95-deficient anergic B cells, however, were not eliminated by CD4+ T cells and were triggered to proliferate. These findings identify a novel regulatory step for eliminating autoreactive B cells that seems unique in its dependence on CD95.

Adenovirus type 5 precursor terminal protein-expressing 293 and HeLa cell lines

HeLa and 293 cell lines that express biologically active adenovirus type 5 precursor terminal protein (pTP) have been made. The amount of pTP synthesized in these cell lines ranges from barely detectable to greater than that observed in cells infected with the wild-type virus. The pTP-expressing cell lines permit the growth of a temperature-sensitive terminal protein mutant virus sub100r at the nonpermissive temperature. A higher percentage of the stably transfected 293 cell lines expressed terminal protein, and generally at considerably higher levels, than did the HeLa cell lines. While 293 cells appeared to tolerate pTP better than did HeLa cells, high-level pTP expression in 293 cells led to a significantly reduced growth rate. The 293-pTP cell lines produce infectious virus after transfection with purified viral DNA and form plaques when overlaid with Noble agar after infection at low multiplicity. These cell lines offer promise for the production of adenoviruses lacking pTP expression and therefore completely defective for replication.

Insufficiency fractures of the sacrum and os pubis

Insufficiency fractures are increasingly seen among postmenopausal women. Sacral fractures are difficult to detect clinically and radiographically, while os pubis fractures may mimic malignancy. Diagnosis is made by bone scintigraphy, supplemented by computed tomography. As patients respond well to conservative management, increased awareness and use of appropriate imaging may avoid unnecessary and invasive investigations.

Sacral insufficiency fractures. Spectrum of radiological features

Clinical and radiological features of 22 Chinese patients with sacral insufficiency fractures were reviewed. Twenty-one were postmenopausal women. Other risk factors were external pelvic radiotherapy (eight) and total hip replacement (two). Severe low back pain was the most common presenting complaint. Fractures initially were demonstrated by bone scintigraphy in 21 and computed tomography (CT) in seven patients. Concomitant parasymphyseal and pubic rami fractures were detected in 17 and 10 patients, respectively. Follow-up assessment by CT and bone scintigraphy in five patients showed various stages of fracture healing. Recognition of the radiological patterns of this entity is emphasized.

Sacral and pubic insufficiency fractures after irradiation of gynaecological malignancies

The association between radiotherapy and insufficiency fractures of the pelvis has not been well documented. Fractures were detected over a 2-year period in eight postmenopausal women who had previously undergone irradiation for gynaecological malignancies. Six of these patients also had local soft tissue complications, such as rectal bleeding and haematuria, in addition to severe low back, buttock or groin pain, caused by the fractures. Plain radiographs were unhelpful in the detection of sacral insufficiency fractures, but showed the pubic fractures in five patients. Diagnoses of insufficiency fractures were made on bone scintigraphic demonstration of the typical 'H' shaped sacral pattern, or the combination of the partial 'H' pattern together with public uptake. Computed tomography was useful for confirmation of insufficiency fractures in doubtful cases. Recognition of insufficiency fractures helps to avoid the pitfalls of misdiagnosing tumour recurrence or bony metastases.

Modulatory effects of endogenous adenosine on epinephrine secretion from the adrenal medulla of the rat

The purpose of this study was to examine (1) whether endogenous adenosine receptors inhibit the release of epinephrine and norepinephrine from adrenal medulla in response to physiological and pharmacological stimuli and (2) whether the renin-angiotensin system modulates this effect of endogenous adenosine. We used a conscious animal model to approximate normal physiological conditions. Male Sprague-Dawley rats were treated with a surface adenosine receptor antagonist, 1,3-dipropyl- 8-(p-sulfophenyl)xanthine (DPSPX) to explore the effect of endogenous adenosine. Plasma epinephrine and norepinephrine levels in response to hydralazine-induced hypotension were measured in these animals. The same protocol was repeated in rats pretreated with either adrenalectomy or captopril. The results showed that DPSPX treatment significantly increased plasma epinephrine and norepinephrine levels at both baseline conditions and after hydralazine-induced hypotension. The results from the adrenalectomized rats showed that the difference in plasma epinephrine level between the control and DPSPX groups originated from the adrenal medulla. Pretreatment with captopril attenuated the rise of plasma epinephrine and norepinephrine levels in DPSPX-treated animals. This result suggests that endogenous adenosine receptors inhibit epinephrine release from the adrenal medulla and suppress plasma norepinephrine levels. When catecholamine release was stimulated by physiological and pharmacological stimuli, this inhibitory function of adenosine receptors was augmented. The renin-angiotensin system is at least partially responsible for the modulatory function of endogenous adenosine on the catecholamine response as demonstrated in this study.

Resting and anergic B cells are defective in CD28-dependent costimulation of naive CD4+ T cells

Successful antibody production in vivo depends on a number of cellular events, one of the most important of these being cognate B cell-T cell interaction. To examine this phenomenon in vitro, homogeneous populations of hen egg lysozyme (HEL)-specific small resting B cells and naive CD4+ HEL-specific T cells (derived from immunoglobulin [Ig] and T cell receptor transgenic mice, respectively) were cultured together. On addition of intact HEL protein. HEL-specific B cells increase their expression of activation molecules, including a B7-related protein and CD44, and enlarge into blast cells. Within the same cultures, HEL-specific CD4+ T cells also increase expression of the activation markers CD69 and CD44, enlarge, secrete lymphokines, and proliferate. This response is radiation sensitive, supporting the conclusion that HEL-specific B cells present antigen to and activate the naive T cells. By contrast, when a synthetic peptide fragment of HEL is used to bypass B cell antigen-receptor engagement, the naive T cells enlarge and display activation antigens, but fail to produce lymphokines, proliferate, or promote B cell blastogenesis. Presentation of HEL by tolerant B cells, which are no longer able to signal effectively through their antigen receptors, results in an identical pattern of incomplete T cell activation. Addition of a stimulating anti-CD28 antibody and blocking of CD28 signals with CTLA4/Ig fusion protein both show that complete activation of naive CD4+ T cells depends on the initial induction of B7 and related costimulatory molecules after HEL binding to nontolerant HEL-specific B cells. Thus, in the absence of adequate constimulation from the B cell, naive CD4+ T cells undergo a form of "partial activation" in which they upregulate surface expression of certain T cell activation antigens, but fail to efficiently produce lymphokine and proliferate. This may explain the different conclusions that have been reached regarding the consequences of B cell antigen presentation to T cells, in that the ability of B cells to activate naive CD4+ T cells depends both on their specificity and their activation state.

A 58-year-old woman with severe low back pain

The following case is presented to illustrate the roentgenographic and clinical findings of a condition of interest to the orthopaedic surgeon. The initial history, physical findings, and roentgenographic examinations are found on this page. The clinical and roentgenographic differential diagnosis is presented on the following pages.

Adenovirus terminal protein mediates both nuclear matrix association and efficient transcription of adenovirus DNA

Adenovirus DNA is tightly bound to the nuclear matrix throughout the course of infection. Analysis of adenovirus DNA from infected HeLa cell nuclei after extraction with lithium diiodosalicylate and digestion with restriction enzymes demonstrated that the sites of tightest attachment occur in the terminal fragments of the linear viral chromosome. Analysis of viruses mutated in the precursor terminal protein coding sequence demonstrated that the terminal protein, which is covalently attached to the 5' end of each DNA strand, mediates the tight binding. Virions containing chromosomes with mutant terminal proteins were unpackaged and viral DNA accumulated in the nucleus at a normal rate and competed for the limiting component during transcription complex formation, but their early genes were transcribed at reduced efficiency by both RNA polymerases II and III. The transcriptional defects were not complemented by coinfection with a wild-type virus. We propose that the adenovirus chromosome may exist as a single chromatin domain during infection and that binding of DNA to the nuclear matrix may play a critical role in adenovirus transcription.

Clinical observation of meconium peritonitis

Twenty cases of meconium peritonitis were found between September 1980 and March 1988 at Mackay Memorial Hospital. The male to female ratio was 1.5 to 1. Six of the 20 cases involved premature babies. The great majority presented symptoms and signs before 5 days old, but one case was not diagnosed until 13 months of age. Polyhydramnios of the mother was found in six cases (30%). Abdominal distension was the universal symptom in all 20 cases. Hydrocele was noticed in 8 of the 12 male babies. In seven cases (35%) radiological examination showed abdominal calcifications. All patients underwent surgical intervention. Peritonitis was of cystic type in seven cases (35%); fibroadhesive in nine cases (45%); generalized in four cases (20%). Evident intestinal perforation was noted in 13 patients, and a mechanical obstructive lesion was found in 9 cases (45%) including intestinal diaphragm, atresia, volvulus, and Hirschsprung's disease. In only two patients (10%) was neither evident perforation nor obstructive lesion. The overall mortality rate was 30% (6/20), with no mortality after 1986 (0/6). The mortality seemed increased in those associated with perforation (4/13) and midgut volvulus (2/2) in particular, compared with non-perforation cases (1/7). It appears that early aggressive operation, and meticulous postoperative care, have contributed to the higher survival rate in recent years.

The XLR sequence family: dispersion on the X and Y chromosomes of a large set of closely related sequences, most of which are pseudogenes

The XLR sequence family encodes RNA transcripts specific to late-stage T and B cells and their neoplasms. Only one apparently functional mRNA has been identified thus far and this encodes a novel 25 kDa nuclear protein. In this report, we find that the XLR gene family is composed of 50-75 copies per haploid genome which localize to at least two different portions of the mouse X chromosome. Neither of these locations are near the xid mutation that earlier work had correlated with XLR. In addition, some members of this family are also on the Y chromosome. Another surprising finding is that while the fourteen genomic clones examined to date have the same exon-intron structure and are closely related with respect to sequence conservation (90%), all appear (in most cases by multiple criteria) to be non-functional, raising the possibility that all but one of the members of this large semi-dispersed family are pseudogenes.

In-vitro stability of beta-lactam antibiotics to hydrolysis by beta-lactamases of Neisseria gonorrhoeae from Southeast Asia

Extracts of penicillinase-producing strains of Neisseria gonorrhoeae obtained from several localities in Southeast Asia exhibited similar patterns of relative rates of hydrolysis of benzylpenicillin, ampicillin, carbenicillin, and cephaloridine. Methicillin and oxacillin were not hydrolyzed. The isoelectric point of the beta-lactamase from these strains was 5.38 +/- 0.05, and the molecular weight was approximately 22.5. These properties, as well as the Km values determined for a range of substrates, were the same for the enzyme purified from one of the strains. These observations are consistent with those reported for other gonococcal beta-lactamases of the TEM-1 type. Cefamandole and to a lesser extent, cefoperazone, were also hydrolyzed by these extracts; however, the newer beta-lactam antibiotics piperacillin, cefuroxime, cefoxitin, ceftriaxone, ceftazidime, and moxalactam were stable. These stable compounds had little inhibitory effect on the activity of the enzyme toward benzylpenicillin or cephaloridine.