SO042WHOLE GENOME SEQUENCING OF HUMAN KIDNEY PROGENITORS IDENTIFIES A MUTATION-PRONE CELL TYPE IN THE PROXIMAL TUBULE

Background and Aims

The genome of every cell accumulates somatic mutations while aging. Somatic mutation data can be used to track a cell´s exposure to mutagens, thereby allowing the discovery of cell types that are more susceptible to mutate and become cancer and the underling mechanisms.

Method

To detect somatic mutations in healthy, human kidney, we set up a protocol for whole genome DNA sequencing of single non-cancer cells. The protocol requires in vitro clonal expansion prior to sequencing, a step that restricts the analysis to cells able to proliferate in vitro (progenitors), but allows a gene expression analysis in addition to genome sequencing. Cells were obtained from six living kidney donors undergoing surgery. In addition to the kidney cortex biopsy, multiple control tissues (skin, subcutaneous fata and visceral fat) were obtained from each donor, allowing a well-controlled comparison of mutation landscapes in different cell types. Donors´ age spanned from 30 to 69.

Results

Somatic mutation and gene expression data showed that we were able to culture two different populations of CD133/CD24 positive, tubular cells. One population showed a low amount of somatic mutations and a mutation profile similar to progenitors from other tissues (fat, skeletal muscle and blood), consistent with a lack of exposure to mutagens. Conversely, the other population showed high mutation burden and a unique mutation landscape, characterized by mutation enrichment in active chromatin, regulatory, and transcribed regions. Accumulation of potential, cancer-driver mutations was 6-fold faster in these compared to control cells. The mutation profile was similar to that of the most common kidney cancer subtypes (clear cell- and papillary cell-carcinoma) and indicated that these cells originated from the proximal tubule, in agreement with gene expression data.

Conclusion

Our somatic mutation data from single genomes support the existence of two different populations of proliferating tubule cells in healthy, human kidney. One is protected from mutagen exposure, similar to stem cells from other organs. The other population is derived from damaged proximal tubule cells and shows a high mutation rate between 30 and 70 years of age. Mutations are enriched in transcribed genes and regulatory regions, thus enhancing the chances of tumorigenic transformation and suggesting conditions that predispose to cancer in the kidney proximal tubule.

Somatic mutation that affects transcription factor binding upstream of CD55 in the temporal cortex of a late-onset Alzheimer disease patient

Alzheimer’s disease (AD) is the most common neurodegenerative disease worldwide. Familial cases suggest genetic components; however, monogenetic causes are few, and the vast majority of incidences have unknown cause. Sequencing efforts have focused on germline mutations, but improved technology has opened up for studies on somatic mutations in affected brain tissue samples. Here we use ultra-deep sequencing on brain and blood from early-onset AD (EOAD) and late-onset AD (LOAD) patients and non-AD individuals (n = 16). In total, 2.86 Mb of genomic regions, previously associated with AD, were targeted included 28 genes and upstream and downstream regulatory regions. Tailored downstream bioinformatics filtering identified 11 somatic single nucleotide variants in the temporal cortex in AD patients and none in the controls. One variant was validated to be present at 0.4% allele frequency in temporal cortex of a LOAD patient. This variant was predicted to affect transcription factor binding sites upstream of the CD55 gene, contributing to AD pathogenesis by affecting the complement system. Our results suggest that future studies targeting larger portions of the genome for somatic mutation analysis are important to obtain an increased understanding for the molecular basis of both EOAD and LOAD.

Whole genome DNA sequencing provides an atlas of somatic mutagenesis in healthy human cells and identifies a tumor-prone cell type

BACKGROUND

The lifelong accumulation of somatic mutations underlies age-related phenotypes and cancer. Mutagenic forces are thought to shape the genome of aging cells in a tissue-specific way. Whole genome analyses of somatic mutation patterns, based on both types and genomic distribution of variants, can shed light on specific processes active in different human tissues and their effect on the transition to cancer.

RESULTS

To analyze somatic mutation patterns, we compile a comprehensive genetic atlas of somatic mutations in healthy human cells. High-confidence variants are obtained from newly generated and publicly available whole genome DNA sequencing data from single non-cancer cells, clonally expanded in vitro. To enable a well-controlled comparison of different cell types, we obtain single genome data (92% mean coverage) from multi-organ biopsies from the same donors. These data show multiple cell types that are protected from mutagens and display a stereotyped mutation profile, despite their origin from different tissues. Conversely, the same tissue harbors cells with distinct mutation profiles associated to different differentiation states. Analyses of mutation rate in the coding and non-coding portions of the genome identify a cell type bearing a unique mutation pattern characterized by mutation enrichment in active chromatin, regulatory, and transcribed regions.

CONCLUSIONS

Our analysis of normal cells from healthy donors identifies a somatic mutation landscape that enhances the risk of tumor transformation in a specific cell population from the kidney proximal tubule. This unique pattern is characterized by high rate of mutation accumulation during adult life and specific targeting of expressed genes and regulatory regions.

Somatic mutagenesis in satellite cells associates with human skeletal muscle aging

Human aging is associated with a decline in skeletal muscle (SkM) function and a reduction in the number and activity of satellite cells (SCs), the resident stem cells. To study the connection between SC aging and muscle impairment, we analyze the whole genome of single SC clones of the leg muscle vastus lateralis from healthy individuals of different ages (21–78 years). We find an accumulation rate of 13 somatic mutations per genome per year, consistent with proliferation of SCs in the healthy adult muscle. SkM-expressed genes are protected from mutations, but aging results in an increase in mutations in exons and promoters, targeting genes involved in SC activity and muscle function. In agreement with SC mutations affecting the whole tissue, we detect a missense mutation in a SC propagating to the muscle. Our results suggest somatic mutagenesis in SCs as a driving force in the age-related decline of SkM function.

Aging skeletal muscle shows declining numbers and activity of satellite cells. Here, Franco et al. show that in satellite cells of the human leg muscle vastus lateralis, somatic mutations accumulate with age and that these mutations become enriched in exons and promoters of genes involved in muscle function.

A novel RNA sequencing data analysis method for cell line authentication

We have developed a novel analysis method that can interrogate the authenticity of biological samples used for generation of transcriptome profiles in public data repositories. The method uses RNA sequencing information to reveal mutations in expressed transcripts and subsequently confirms the identity of analysed cells by comparison with publicly available cell-specific mutational profiles. Cell lines constitute key model systems widely used within cancer research, but their identity needs to be confirmed in order to minimise the influence of cell contaminations and genetic drift on the analysis. Using both public and novel data, we demonstrate the use of RNA-sequencing data analysis for cell line authentication by examining the validity of COLO205, DLD1, HCT15, HCT116, HKE3, HT29 and RKO colorectal cancer cell lines. We successfully authenticate the studied cell lines and validate previous reports indicating that DLD1 and HCT15 are synonymous. We also show that the analysed HKE3 cells harbour an unexpected KRAS-G13D mutation and confirm that this cell line is a genuine KRAS dosage mutant, rather than a true isogenic derivative of HCT116 expressing only the wild type KRAS. This authentication method could be used to revisit the numerous cell line based RNA sequencing experiments available in public data repositories, analyse new experiments where whole genome sequencing is not available, as well as facilitate comparisons of data from different experiments, platforms and laboratories.

Gd-Dtpa-Enhanced Mr Imaging of Pituitary Macroadenomas

In a study comprising 40 patients with pituitary macroadenomas, MR imaging was performed before and after administration of Gd-DTPA. Before contrast administration T1- and T2-weighted images were obtained, and after the injection, frontal and/or sagittal T1-weighted images. Tumour extension and delineation, relationship to adjacent structures, and signal intensity patterns were evaluated. Compared with pre-contrast T1-weighted images only, post-contrast images provided considerable additional information, but not infrequently this information could also be extracted from pre-contrast T2-weighted images. Post-contrast images were superior regarding the tumour relationship to the cavernous sinus and to the normal pituitary tissue. T2-weighted images were helpful in the diagnosis of degenerative changes, in particular intratumoural haemorrhage. A positive correlation was found between the T2 value (from dual echo sequences) and the degree of enhancement in areas with an appearance of solid tumour tissue, and the enhancement was significantly lower in GH-secreting tumours than in non-secreting ones. It is concluded that the use of Gd-DTPA is often justified in pituitary macroadenomas, particularly in pre-operative evaluation.

Comparison of MR Imaging and CT in Pituitary Macroadenomas

The findings on mid-field MR imaging and CT were compared retrospectively in 65 patients with pituitary macroadenomas. The evaluation comprised tumour extension and delineation, invasiveness, relationship to adjacent structures, and internal tumoral changes. MR was superior to CT except in the demonstration of bone changes and tumour calcification. The superiority of MR was most pronounced regarding cavernous sinus invasion, tumour relationship to the carotid arteries and optic chiasm, and tumour haemorrhage. Extensive bone changes were visualized with both methods; erosions were often seen only with CT. It is concluded that MR is the preferable method for evaluation of pituitary macroadenomas. CT is useful as a supplementary modality when detailed information on bone anatomy is required, particularly if a transsphenoidal surgical approach is contemplated.

Quantitative multigene FISH on breast carcinomas identifies der(1;16)(q10;p10) as an early event in luminal A tumors

In situ detection of genomic alterations in cancer provides information at the single cell level, making it possible to investigate genomic changes in cells in a tissue context. Such topological information is important when studying intratumor heterogeneity as well as alterations related to different steps in tumor progression. We developed a quantitative multigene fluorescence in situ hybridization (QM FISH) method to detect multiple genomic regions in single cells in complex tissues. As a “proof of principle” we applied the method to breast cancer samples to identify partners in whole arm (WA) translocations. WA gain of chromosome arm 1q and loss of chromosome arm 16q are among the most frequent genomic events in breast cancer. By designing five specific FISH probes based on breakpoint information from comparative genomic hybridization array (aCGH) profiles, we visualized chromosomal translocations in clinical samples at the single cell level. By analyzing aCGH data from 295 patients with breast carcinoma with known molecular subtype, we found concurrent WA gain of 1q and loss of 16q to be more frequent in luminal A tumors compared to other molecular subtypes. QM FISH applied to a subset of samples (n = 26) identified a derivative chromosome der(1;16)(q10;p10), a result of a centromere-close translocation between chromosome arms 1q and 16p. In addition, we observed that the distribution of cells with the translocation varied from sample to sample, some had a homogenous cell population while others displayed intratumor heterogeneity with cell-to-cell variation. Finally, for one tumor with both preinvasive and invasive components, the fraction of cells with translocation was lower and more heterogeneous in the preinvasive tumor cells compared to the cells in the invasive component. © 2014 The Authors Genes, Chromosomes & Cancer Published by Wiley Periodicals, Inc.

Bioimpedance spectroscopy: a new tool to assess early esophageal changes linked to gastroesophageal reflux disease?

Bioimpedance spectroscopy can identify pathological changes related to precancerous lesions of the cervix uteri and esophagus. It therefore has the potential to detect early reflux-related changes in the esophageal mucosa, such as dilated intercellular spaces. The reliable detection of dilated intercellular spaces at the time of endoscopy would yield a significant diagnostic advantage for separating patients with functional heartburn from the large proportion of patients with gastroesophageal reflux symptoms but no macroscopic esophagitis or pathological acid exposure. The bioimpedance of the esophageal mucosa, measured with a small caliber probe, was evaluated in a series of preclinical experiments. First, sections of rabbit esophageal epithelium were mounted in Ussing chambers and exposed to solutions at pH 7.4 or pH 1.5 for 45 minutes. Impedance measurements were taken at varying probe pressures. Second, rabbit esophageal epithelia were perfused for 45 minutes in situ with pH 1.1 or control solutions and impedance measurements taken. Samples from both in vitro and in situ experiments were taken for morphological examination by light microscopy. Finally, esophageal bioimpedance was measured in awake dogs with permanent esophagocutaneous stoma. The in situ experiments demonstrated that morphological changes in the esophageal mucosa could be discerned by the use of bioimpedance spectroscopy. The variability in resistivity was species-independent but was affected by the pressure applied to the probe. The results suggest that evaluation of bioimpedance spectroscopy for use in a clinical setting is warranted. Small morphological differences in the esophageal mucosa may be detected by the use of bioimpedance spectroscopy.

Documenting the Use of Computers in Swedish Health Care up to 1980

This paper describes a documentation project to create, collect and preserve previously unavailable sources on informatics in Sweden (including health care as one of 16 subgroups), and mak- ing them available on the Web. Time was critical as the personal docu- mentation and artifacts of early pioneers could be irretrievablylost. The criteria for participation were that a person had developed a system in a clinical environment which was used by others prior to 1980.

Participants were interviewed and asked for early docu- mentation such as notes, minutes from meetings, drawings, test results and early models – together with related artifacts. The ap- proach included traditional oral history interviews, collection of au- tobiographies and new self-structuring and time saving methods, such as witness seminars and an Internet-based repository of their recollections (the Writers’ Web).

The combination of methods obtained new information on system errors, and challenges in reaching the goals due partly to inadequacies of the early technology, and partly to the insufficient understanding of the complexity of the many problems which needed to be solved before a useful electronic patient record could be realized. A very important result was the development of a method to collect information in an easier, faster and much less expensive way than using the traditional scientific method, and still reach results that are qualitative and quantitative for the purpose of documenting the early period of computer-based health care technology. The wit- ness seminars and the Writers’ Web yielded especially large amounts of hitherto-unknown information. With all material in one database available to everyone on the Web, it is accessed very frequently - es- pecially by students, researchers, journalists and teachers.

Study of the materials explains and clarifies the reasons behind the delays and difficulties that have been encountered in de- veloping electronic patient records, as described in an article [3] published in the IMIA Yearbook 2006.

Subtypes of Hepatitis B Antigen in Blood Donors and Post-transfusion Hepatitis: Clinical and Epidemiological Aspects

Subtyping of hepatitis B antigen (HBA) in blood donors revealed subtype ad in 56% while patients with icteric post-transfusion hepatitis from the same centre showed subtype ay in the majority of the cases (75%). Donors with subtype ad in serum were mostly asymptomatic long-term carriers of the antigen with normal liver function (83%), while 70% of donors with subtype ay in serum had signs of acute or chronic liver disease. Healthy long-term carriers of HBA seem to present little risk of transmitting hepatitis irrespective of subtype. It is, however, possible that these differences in blood donors with subtype ad and patients with post-transfusion hepatitis with subtype ay might reflect epidemiological circumstances rather than biological differences in the two viral strains.

Genomic architecture characterizes tumor progression paths and fate in breast cancer patients

Distinct molecular subtypes of breast carcinomas have been identified, but translation into clinical use has been limited. We have developed two platform-independent algorithms to explore genomic architectural distortion using array comparative genomic hybridization data to measure (i) whole-arm gains and losses [whole-arm aberration index (WAAI)] and (ii) complex rearrangements [complex arm aberration index (CAAI)]. By applying CAAI and WAAI to data from 595 breast cancer patients, we were able to separate the cases into eight subgroups with different distributions of genomic distortion. Within each subgroup data from expression analyses, sequencing and ploidy indicated that progression occurs along separate paths into more complex genotypes. Histological grade had prognostic impact only in the luminal-related groups, whereas the complexity identified by CAAI had an overall independent prognostic power. This study emphasizes the relation among structural genomic alterations, molecular subtype, and clinical behavior and shows that objective score of genomic complexity (CAAI) is an independent prognostic marker in breast cancer.

Documenting the use of computers in Swedish Health Care up to 1980

OBJECTIVES

This paper describes a documentation project to create, collect and preserve previously unavailable sources on informatics in Sweden (including health care as one of 16 subgroups), and making them available on the Web. Time was critical as the personal documentation and artifacts of early pioneers could be irretrievably lost. The criteria for participation were that a person had developed a system in a clinical environment which was used by others prior to 1980.

METHODS

Participants were interviewed and asked for early documentation such as notes, minutes from meetings, drawings, test results and early models - together with related artifacts. The approach included traditional oral history interviews, collection of autobiographies and new self-structuring and time saving methods, such as witness seminars and an Internet-based repository of their recollections (the Writers' Web).

RESULTS

The combination of methods obtained new information on system errors, and challenges in reaching the goals due partly to inadequacies of the early technology, and partly to the insufficient understanding of the complexity of the many problems which needed to be solved before a useful electronic patient record could be realized. A very important result was the development of a method to collect information in an easier, faster and much less expensive way than using the traditional scientific method, and still reach results that are qualitative and quantitative for the purpose of documenting the early period of computer-based health care technology. The witness seminars and the Writers' Web yielded especially large amounts of hitherto-unknown information. With all material in one database available to everyone on the Web, it is accessed very frequently - especially by students, researchers, journalists and teachers.

CONCLUSIONS

Study of the materials explains and clarifies the reasons behind the delays and difficulties that have been encountered in developing electronic patient records, as described in an article [3] published in the IMIA Yearbook 2006.

Inferring tumor progression from genomic heterogeneity

Cancer progression in humans is difficult to infer because we do not routinely sample patients at multiple stages of their disease. However, heterogeneous breast tumors provide a unique opportunity to study human tumor progression because they still contain evidence of early and intermediate subpopulations in the form of the phylogenetic relationships. We have developed a method we call Sector-Ploidy-Profiling (SPP) to study the clonal composition of breast tumors. SPP involves macro-dissecting tumors, flow-sorting genomic subpopulations by DNA content, and profiling genomes using comparative genomic hybridization (CGH). Breast carcinomas display two classes of genomic structural variation: (1) monogenomic and (2) polygenomic. Monogenomic tumors appear to contain a single major clonal subpopulation with a highly stable chromosome structure. Polygenomic tumors contain multiple clonal tumor subpopulations, which may occupy the same sectors, or separate anatomic locations. In polygenomic tumors, we show that heterogeneity can be ascribed to a few clonal subpopulations, rather than a series of gradual intermediates. By comparing multiple subpopulations from different anatomic locations, we have inferred pathways of cancer progression and the organization of tumor growth.

Multiple attacks of jaundice associated with repeated sulfonamide treatment

Four women who were treated with sulfonamides because of recurrent urinary tract infections experienced adverse liver reactions with jaundice during their third, fourth and fifth course of treatment, respectively. In spite of this, sulfonamide treatment was reinitiated some years later. Adverse liver reactions with jaundice recurred on all occasions. The clinical picture of the liver reactions was indistinguishable from that of viral hepatitis and a hepatitis-like reaction was also seen histologically. Signs of fibrosis appeared histologically after a third attack of jaundice associated with sulfonamides in one patient, but otherwise no persisting abnormalities were noted.

Inclusion of electric octupole contributions explains the fast radiative decays of two metastable states in Ar+

A laser probing investigation has yielded the lifetimes of the 3s(2)3p(4)(1D)3d (2)G(7/2,9/2) metastable doublet states of Ar+. The results, obtained with the CRYRING ion storage ring of Stockholm, are 3.0+/-0.4 and 2.1+/-0.1 s, respectively. Comparisons with theoretical values calculated with two independent theoretical approaches, i.e., the pseudorelativistic Hartree-Fock method and the multiconfiguration Breit-Pauli approach, have allowed us to establish the unexpected and extraordinary strong contribution of an electric octupole (E3) transition to the ground state, in addition to the M1 decay channels to the 3d ;{2,4}F states and the E2 contributions to the 4s 2P, 2D states.

Magnetic resonance imaging for preoperative staging of rectal cancer in clinical practice: high accuracy in predicting circumferential margin with clinical benefit

OBJECTIVE

The aims were to determine agreement between staging of rectal cancer made by magnetic resonance imaging (MRI) and histopathological examination and the influence of MRI on choice of radiotherapy (RT) and surgical procedure.

METHOD

In this retrospective audit, preoperative MRI was performed on 91 patients who underwent bowel resection, with 93% having total mesorectal excision. Tumour stage according to mural penetration, nodal status and circumferential resection margin (mCRM) involvement was assessed and compared with histopathology.

RESULTS

Five radiologists interpreted the images. Overall agreement between MRI and histopathology for T stage was 66%. The greatest difficulty was in distinguishing between T1, T2 and minimal T3 tumours. The accuracy for mCRM (MRI) was 86% (78/91),with an interobserver variation between 80% and 100%. In the 13 cases with no agreement between mCRM and pCRM (pathological), seven had long-term RT and nine en bloc resections, indicating that the margins initially were involved with an even higher accuracy for mCRM. Preoperative short-term RT was routine, but based on MRI findings, choice of RT was affected in 29 cases (32%); 17 patients had no RT and 12 long-term RT. The surgical procedure was affected in 17 cases (19%) with planned perirectal en bloc resections in all. CRM was involved (< or = 1 mm) in 14.7% of the 34 cases in which MRI had an effect upon choice of RT and/or surgery compared with 8.8% of the remaining 57 cases where it had no impact.

CONCLUSION

Magnetic resonance imaging predicted CRM with high accuracy in rectal cancer. MRI could be used as a clinical guidance with high reliability as indicated by the low figures of histopathologically involved CRM.

Novel patterns of genome rearrangement and their association with survival in breast cancer

Representational Oligonucleotide Microarray Analysis (ROMA) detects genomic amplifications and deletions with boundaries defined at a resolution of approximately 50 kb. We have used this technique to examine 243 breast tumors from two separate studies for which detailed clinical data were available. The very high resolution of this technology has enabled us to identify three characteristic patterns of genomic copy number variation in diploid tumors and to measure correlations with patient survival. One of these patterns is characterized by multiple closely spaced amplicons, or "firestorms," limited to single chromosome arms. These multiple amplifications are highly correlated with aggressive disease and poor survival even when the rest of the genome is relatively quiet. Analysis of a selected subset of clinical material suggests that a simple genomic calculation, based on the number and proximity of genomic alterations, correlates with life-table estimates of the probability of overall survival in patients with primary breast cancer. Based on this sample, we generate the working hypothesis that copy number profiling might provide information useful in making clinical decisions, especially regarding the use or not of systemic therapies (hormonal therapy, chemotherapy), in the management of operable primary breast cancer with ostensibly good prognosis, for example, small, node-negative, hormone-receptor-positive diploid cases.

High-resolution ROMA CGH and FISH analysis of aneuploid and diploid breast tumors

Combining representational oligonucleotide microarray analysis (ROMA) of tumor DNA with fluorescence in situ hybridization (FISH) of individual tumor cells provides the opportunity to detect and validate a wide range of amplifications, deletions, and rearrangements directly in frozen tumor samples. We have used these combined techniques to examine 101 aneuploid and diploid breast tumors for which long-term follow-up and detailed clinical information were available. We have determined that ROMA provides accurate and sensitive detection of duplications, amplifications, and deletions and yields defined boundaries for these events with a resolution of <50 kbp in most cases. We find that diploid tumors exhibit fewer rearrangements on average than aneuploids, but rearrangements occur at the same locations in both types. Diploid tumors reflect at least three consistent patterns of rearrangement. The reproducibility and frequency of these events, especially in very early stage tumors, provide insight into the earliest chromosomal events in breast cancer. We have also identified correlations between certain sets of rearrangement events and clinically relevant parameters such as long-term survival. These correlations may enable novel prognostic indicators for breast and other cancers as more samples are analyzed.

PROBER: oligonucleotide FISH probe design software

PROBER is an oligonucleotide primer design software application that designs multiple primer pairs for generating PCR probes useful for fluorescence in situ hybridization (FISH). PROBER generates Tiling Oligonucleotide Probes (TOPs) by masking repetitive genomic sequences and delineating essentially unique regions that can be amplified to yield small (100-2000 bp) DNA probes that in aggregate will generate a single, strong fluorescent signal for regions as small as a single gene. TOPs are an alternative to bacterial artificial chromosomes (BACs) that are commonly used for FISH but may be unstable, unavailable, chimeric, or non-specific to small (10-100 kb) genomic regions. PROBER can be applied to any genomic locus, with the limitation that the locus must contain at least 10 kb of essentially unique blocks. To test the software, we designed a number of probes for genomic amplifications and hemizygous deletions that were initially detected by Representational Oligonucleotide Microarray Analysis of breast cancer tumors.

AVAILABILITY

http://prober.cshl.edu

Large-scale copy number polymorphism in the human genome

The extent to which large duplications and deletions contribute to human genetic variation and diversity is unknown. Here, we show that large-scale copy number polymorphisms (CNPs) (about 100 kilobases and greater) contribute substantially to genomic variation between normal humans. Representational oligonucleotide microarray analysis of 20 individuals revealed a total of 221 copy number differences representing 76 unique CNPs. On average, individuals differed by 11 CNPs, and the average length of a CNP interval was 465 kilobases. We observed copy number variation of 70 different genes within CNP intervals, including genes involved in neurological function, regulation of cell growth, regulation of metabolism, and several genes known to be associated with disease.

Importance of an M2 depopulating channel for a Kr II metastable state

An experimental investigation of the radiative lifetime of the metastable 4s24p4(3P)4d4D7/2 level in Kr II shows an unusual situation regarding the importance of an M2 depopulation channel. While the first order M1 and E2 channels are expected to contribute in a dominant way to the decay, the experimental result, obtained using a laser probing technique on a stored ion beam, tau = 0.57+/-0.03 s, is far too short to be due to these channels according to our relativistic multiconfiguration Dirac-Fock calculation. Only if second order contributions to the decay branches (including essentially the M2 contribution) are taken into account in the calculations could the unexpected short lifetime be explained.

Radiative lifetime of a bound excited state of Te-

We report on the first experimental study of the lifetime of a bound excited state of a negative ion. A new experimental technique was developed and used to measure the radiative lifetime of the 5p(5) (2)P(1/2) level of Te-. The experiment was performed in a magnetic storage ring, where a laser beam was applied along one of the straight sections. In the experiment the population of the excited J=1/2 level was probed each time the Te- ions passed through the laser field. A decay curve was built up by sampling the population of the excited level of the Te- ions as a function of time after injection into the ring. A multiconfiguration Dirac-Hartree-Fock calculation was performed in conjunction with the experiment. The calculation yielded a radiative lifetime of 0.45 s, in excellent agreement with the measured value of 0.42(5) s.

A pharmacoscintigraphic evaluation of oral budesonide given as controlled-release (Entocort) capsules

AIMS

To investigate the gastrointestinal pharmacokinetics of controlled-release (Entocort) and standard budesonide capsules.

METHODS

Six Crohn's disease patients and eight healthy controls were given controlled-release capsules containing budesonide and an inert 111In label, following breakfast. In the patients, a standard capsule containing deuterium-labelled budesonide was given simultaneously. In the controls, on a separate occasion, the controlled-release capsules were given in the fasting state. Gastrointestinal transit was recorded by a gamma camera. Plasma budesonide and deuterium-labelled budesonide were used to estimate drug release, and urine cortisol was used to assess systemic effects.

RESULTS

Budesonide delivery to the ileo-colonic region was significantly greater after the intake of the controlled-release capsules [69%; 95% confidence interval (CI), 54-84] than after the standard capsules (30%; 95% CI, 15-45) (P = 0.005). Fasting had little impact on uptake. The transit and pharmacokinetics of budesonide were similar in both subject groups, although systemic availability was higher in patients (21%; 95% CI, 13-33) than in controls (12%; 95% CI, 10-14) (P = 0.009). Urinary cortisol was, however, similar in both groups.

CONCLUSIONS

A major fraction of budesonide is released in the ileum and throughout the colon, the intended target for the controlled-release formulation. The prandial state has little effect on budesonide uptake.

Effect of food on the pharmacokinetics of budesonide controlled ileal release capsules in patients with active Crohn's disease

AIM

To study the influence of food on the systemic availability of budesonide in patients with active Crohn's disease.

METHODS

Eight patients with an established diagnosis of Crohn's disease each received 9 mg budesonide controlled ileal release (CIR) capsules (Entocort capsules) orally on two separate occasions: once in a fasting state and once after a heavy breakfast. For reference, deuterium-labelled ((2)H(8)) budesonide, 0.5 mg, was given intravenously. Plasma concentrations of budesonide and (2)H(8)-budesonide were determined for 12 h, and their pharmacokinetic parameters were calculated.

RESULTS

Average systemic availability of budesonide during fasting conditions was 10.7%, area under the curve was 27.5 nmol/L x h and peak plasma concentration was 4.1 nmol/L. Corresponding postprandial values were 13.2%, 27.0 nmol/L x h and 3. 8 nmol/L. Food increased the mean absorption time from 4.5 to 6.8 h (P=0.0012). Body clearance of budesonide was about 25% higher after eating (P=0.0015).

CONCLUSIONS

Food had little influence on systemic availability and peak plasma concentrations of budesonide administered in CIR capsules. Absorption was retarded postprandially, likely due to delayed gastric emptying. Budesonide in CIR capsules can be administered at the same dose regardless of prandial status in patients with Crohn's disease.

Women react with more myocardial ischemia and angina pectoris during elective percutaneous transluminal coronary angioplasty

BACKGROUND

Women have been considered to be at higher risk of complications relating to percutaneous transluminal coronary angioplasty (PTCA) than are men. One reason for this sex-related difference could be the ischemic response of myocardium during the procedure.

OBJECTIVE

To investigate whether there are sex-related differences in ischemic response of myocardium during elective PTCA.

METHODS

Consecutive patients (n = 192, of whom 48 were women), were subjected to vectorcardiography during the PTCA procedure. Vectorcardiographic variables, magnitude of ST-segment vector (ST-VM), and magnitude of ST-segment vector change (STC-VM) were studied.

RESULTS

Women were older (63 +/- 10 versus 56 +/- 10 years, P< 0.001) than men in our study and more often had diabetes mellitus and hypertension. Women less often had stents implanted (24 versus 50%, P < 0.01) and they were subjected to fewer balloon inflations (P < 0.001), with a total inflation time shorter than that for men (P< 0.001). Maximum STC-VM was 25% greater for women (P < 0.05). Women reported greater maximum pain (P < 0.05) and nitroglycerine was more frequently used for them during PTCA (P < 0.05). Occurrence of episodes of residual ischemic STC-VM (the difference between total number of episodes and number of balloon inflations) was more common for women (3 +/- 5 versus 1 +/- 3, P< 0.01). Duration of residual ischemic STC-VM episodes (the difference between total duration of episodes and duration of balloon inflations) was longer for women than it was for men (242 +/- 275 versus 148 +/- 233 s, P < 0.05). In a stepwise multivariate analysis and for a matched case-control group, episodes of residual STC-VM and duration of residual STC-VM episodes still indicated that there was an independent sex-related difference (P < 0.01 and P < 0.01, respectively).

CONCLUSIONS

Women more commonly develop vectorcardiographic signs of severe myocardial ischemia, more frequently experience episodes of ischemia and report more severe angina pectoris during elective PTCA than do men.

Prognostic value of ischemia monitoring with on-line vectorcardiography in patients with unstable coronary artery disease

AIM

The aim of this study was to determine whether on-line vectorcardiography (VCG) gives independent prognostic information, regarding death, myocardial infarction (MI), and revascularization in patients with unstable coronary artery disease, i.e. unstable angina or non-Q-wave MI.

METHODS AND RESULTS

One hundred and fifty patients (mean age 69 +/- 10), participating in a randomized study of low-molecular-weight heparin in unstable coronary artery disease, were studied with on-line VCG recordings for 24 h. During a 5-6-month follow-up, 11 patients died, 14 suffered a nonfatal MI and 31 were revascularized. Univariate predictors of death were diabetes mellitus (p < 0.01), maximum ST vector magnitude (ST-VM; p < 0.001), maximum ST change vector magnitude (STC-VM; p < 0.001), number of ST-VM (p < 0.01) and STC-VM episodes (p < 0.001). In multivariate analysis, the number of STC-VM episodes (p < 0.01) and diabetes mellitus (p < 0.02) each gave independent prognostic information regarding death. When all cardiovascular events were combined, the inability to perform an exercise test (p < 0.05), maximum value of ST-VM (p < 0.01) and STC-VM (p < 0.001), the number of episodes of STC-VM (p < 0.001) and ST-VM (p < 0.001) all gave prognostic information. In multivariate analysis, the inability to perform an exercise test and the number of STC-VM episodes were independent predictors.

CONCLUSION

VCG monitoring during the first 24 h of hospitalization for unstable coronary artery disease gives independent prognostic information.

Prognostic role of on-line vectorcardiography as regards repeat revascularization after successful coronary angioplasty

This study evaluated the prognostic significance of continuous on-line vectorcardiography (VCG) during elective coronary angioplasty (percutaneous transluminal coronary angioplasty, PTCA). Patients (n = 192, mean age 58 +/- 10), treated with elective and initially successful PTCA, were included. VCG monitoring was started before start of the PTCA procedure and was carried out during the entire procedure. ST vector magnitude (ST-VM) was monitored. A 6-month follow-up was obtained. Main outcome measures were the frequency of cardiac events and revascularization during follow-up. During follow-up, 1 patient died, 6 suffered a nonfatal myocardial infarction and 50 were revascularized. Angiography revealed restenosis in 88% of the patients who had a revascularization. In the total patient group, the VCG predictor of revascularization was the total ischemic time of all ST-VM episodes (p = 0.05). Clinical predictors of revascularization were diabetes mellitus (p < 0.01), a more severe type of lesion (type B; p < 0.01), percent post-PTCA stenosis (p < 0.05), nominal balloon size (p < 0.01), maximum balloon pressure (p < 0.05) and no stent implanted (p < 0.001). In a multivariate analysis all the above significant univariate variables of revascularization were entered. Total ischemic time of ST-VM (p < 0.01) was the best variable giving independent prognostic information. In the nonstent group, total ischemic time of ST-VM (p < 0.01) was the only independent predictor of a further revascularization. In conclusion, VCG monitoring during elective PTCA gives on-line information that identifies patients at an increased risk of a revascularization during 6 months after the initial procedure.

Diabetes mellitus is a strong negative prognostic factor in patients with myocardial infarction treated with thrombolytic therapy

OBJECTIVES

To assess the long-term prognostic values of baseline demographic data, occurrence of vectorcardiographic signs of reperfusion, left ventricular function and coronary angiographic features.

DESIGN

Longitudinal study of morbidity and mortality.

SETTING

Coronary care unit at Danderyd Hospital, Stockholm, Sweden.

SUBJECTS

A total of 222 patients (mean age 61 years) with a suspected acute myocardial infarction treated with thrombolysis were investigated and followed for 2-5 years (mean 1216 days).

MAIN OUTCOME MEASURES

Death or a new myocardial infarction.

RESULTS

Age above 55 years (P < 0.05), a previous diagnosis of diabetes mellitus (P < 0.005), hypertension (P < 0.05), heart failure (P < 0.001) and myocardial infarction (P < 0.05), a previous use of beta-blockers (P < 0.05) and an ejection fraction below 60% (P < 0.01) were predictors for death or a new myocardial infarction in univariate analysis. Sex, a previous history of smoking or angina pectoris, vectorcardiographic signs of reperfusion or degree of coronary artery disease had no prognostic values. In multivariate analysis including age above 55 years, a previous diagnosis of diabetes mellitus, hypertension and myocardial infarction, and an ejection fraction below 60%, only age (P < 0.05), diabetes mellitus (P < 0. 01) and ejection fraction (P < 0.05) were predictors for death or a new myocardial infarction.

CONCLUSIONS

The results of the present study emphasize the importance of diabetes mellitus as a long-term prognostic risk factor in patients with myocardial infarction treated with thrombolysis. Further studies are needed to determine the mechanisms behind this increased risk.

Imaging of aortoiliac arterial disease. Duplex ultrasound and MR angiography versus digital subtraction angiography

PURPOSE

To evaluate and compare the diagnostic accuracy of duplex ultrasound (US) and MR angiography (MRA) at 1.0 T in aortoiliac arterial disease using digital subtraction angiography (DSA) as the reference standard. In addition, a comparison of the 2D time-of-flight (TOF) and 3D contrast-enhanced MRA (CE MRA) techniques was performed.

MATERIAL AND METHODS

Prospectively, 39 patients with symptoms of lower-extremity arterial occlusive disease were examined using US, TOF MRA, CE MRA and DSA. Significant lesions (stenosis > or =50%) and occlusions were evaluated blindly for each method.

RESULTS

For all segments, the sensitivity for US, TOF MRA and CE MRA with regard to significant lesions was 0.72, 0.81 and 0.81, respectively, and the specificity for each was 0.97, 0.91 and 0.92, respectively. For significant lesions above the inguinal ligament the corresponding sensitivity was 0.84, 0.89 and 0.94 and the specificity 0.93, 0.82 and 0.73, respectively. The specificity was higher when the two MRA methods were combined. TOF MRA overgraded 7 segments as occluded. In most cases, the length of the occlusions was correctly determined on CE MRA, overestimated on TOF MRA and uncertain on US.

CONCLUSION

Neither US nor MRA were sufficiently accurate to fully replace angiography. MRA was preferable to US as a non-invasive test when vascular intervention was contemplated. Although CE MRA was superior to TOF MRA, the most accurate results were achieved when the two methods were combined.

On-line vectorcardiography during elective coronary angioplasty indicates procedure-related myocardial infarction

BACKGROUND

Increased creatine kinase concentrations after elective percutaneous transluminal coronary angioplasty (PTCA) have been shown to be associated with increased late cardiac mortality.

OBJECTIVE

To evaluate the potential of continuous on-line vectorcardiography during elective PTCA to identify procedure-related myocardial infarction.

METHODS

Patients (n = 192, ages 58 +/- 10 years), treated with elective and initially successful PTCA, were studied using vectorcardiogram (VCG) recordings. VCG monitoring was started 5 min before start of the PTCA and was carried out during the entire procedure, for at least 30 min after the first balloon inflation. ST-segment vector magnitude (ST-VM) and ST-segment change vector magnitude (STC-VM) were monitored.

RESULTS

Fifteen (7.8%) procedure-related myocardial infarctions occurred. Indicators of procedure-related myocardial infarction were maximum value of ST-VM (P < 0.001) and STC-VM (P < 0.001), total ischemic time of all ST-VM episodes (P < 0.001) and STC-VM episodes (P < 0.001). The variable most closely related to a procedure-related myocardial infarction was the maximum STC-VM value during the procedure. With an optimized cutoff value, maximum STC-VM predicts a procedure-related myocardial infarction with a sensitivity of 93%, a specificity of 59% and a negative predictive value of 99%. Patients who had a stent implanted had significantly greater VCG values (P < 0.05-P < 0.001) than the group without a stent. There was a trend (P < 0.06) to a relation between increased creatine kinase concentration and stent implantation. In patients both with and without an implanted stent, greater STC-VM values were associated with procedure-related myocardial infarction (P < 0.01).

CONCLUSION

Continuous VCG monitoring during elective PTCA is a promising method for immediate detection of patients at increased risk of procedure-related myocardial infarction.

Respiratory monitoring during MR imaging. The clinical value of a new fibre-optical monitor

PURPOSE

To assess the clinical utility of a fibre-optical monitor for respiratory monitoring in patients undergoing MR imaging without general anaesthesia.

MATERIAL AND METHODS

One hundred consecutive patients were included at each of 3 MR units (300 patients in total). The technicians estimated the value of monitoring the respiratory rate on a 5-graded scale. Conditions that might complicate the MR examination were noted.

RESULTS

The respiratory monitor was well tolerated by 99% of the patients. It was rated as valuable or very valuable in one-third of the total group, but in slightly more than two-thirds of the group of patients with some condition that might have complicated the MR examination. The estimated value of respiratory rate monitoring did not correlate to the age or sex of the patients, the type of examination, or to whether contrast medium was used or not, but it was significantly more often considered valuable in patients placed in the head-first position than in those placed in feet-first.

CONCLUSION

Respiratory rate monitoring during MR imaging seems to be valuable in many patients, particularly if some condition that might complicate the MR examination is present.

Ischaemia monitoring with on-line vectorcardiography during dobutamine stress echocardiography in patients after an episode of unstable coronary artery disease

OBJECTIVES

This study investigated the ability of on-line vectorcardiography (VCG) to detect myocardial ischaemia as assessed by dobutamine stress echocardiography after an episode of unstable coronary artery disease.

DESIGN

Dobutamine stress test (incrementally infused doses of 5, 10, 20, 30 and 40 microg kg(-1) per minute) was performed during simultaneous VCG monitoring. QRS vector difference (QRS-VD), ST vector magnitude (ST-VM), ST change vector magnitude (STC-VM) and T change vector magnitude (TC-VM) were monitored. A new wall motion abnormality or worsening of abnormal wall motion was regarded as indicating a positive dobutamine stress test.

SUBJECTS

Fifty-five patients with unstable angina pectoris and 16 patients with an acute non-Q-wave myocardial infarction were studied 5-8 days after admission.

RESULTS

A positive dobutamine stress test was observed in 37 patients (52%). The sensitivity, specificity and total accuracy of identifying patients with a positive dobutamine stress test by VCG were: 38%, 91% and 63% for QRS-VD; 59%, 88% and 73% for ST-VM; 84%, 79% and 82% for STC-VM; and 86%, 23% and 56% for TC-VM. Patients with a positive dobutamine stress test showed higher maximum VCG values than patients with a negative dobutamine stress test (QRS-VD, P < 0.01; ST-VM, P < 0.001; STC-VM, P < 0.001). The maximum VCG values were related to the number of segments showing new or worsening wall motion abnormality (QRS-VD: r=0.41, P < 0.001; ST-VM: r=0.44, P < 0.001; STC-VM: r=0.57, P < 0.001).

CONCLUSION

STC-VM and ST-VM seem to be the best VCG variables for detection of myocardial ischaemia as assessed by dobutamine stress echocardiography.

Comparison of electrocardiograms recorded with standard leads and derived from the vectorcardiographic frank leads in high risk patients

Dynamic vectorcardiography (VCG) is increasingly employed for ischaemia monitoring with the use of a computerized method for recording and on-line analysis by the calculation of trend parameters. To elucidate how well the derived electrocardiogram (dECG), calculated from the VCG, compares with the simultaneously registered standard ECG (sECG), dECGs from 17 postoperative cardiac-risk patients and 36 subjects with acute myocardial infarction (AMI) were compared to sECGs, both quantitatively in leads II, III, V2 and V5 and qualitatively. Despite small, but some significant differences, mainly in the amplitudes of precordial leads, the qualitative interpretation by two independent cardiologists showed good agreement between the methods (kappa = 0.72 and 0.67, respectively) for the diagnosis of AMI/ischaemia. The dECG seems to be reliable and can be used clinically in these groups of patients during VCG recordings.

Reproducibility of on-line vectorcardiography measurements in patients with and without acute ischaemic heart disease

OBJECTIVES

The aim of the present study was to determine inter and intraobserver variations of measurements with on-line vectorcardiography (VCG).

DESIGN

The VCG registrations were evaluated by two independent observers. One observer also evaluated the VCG registrations on two separate occasions. Monitored VCG variables were: ST vector magnitude (ST-VM), ST vector lead X (ST-X), ST change vector magnitude (STC-VM) and QRS vector difference (QRS-VD).

SUBJECTS

On-line VCG was performed for 24 hours in 60 patients (10 with low probability of ischaemic heart disease, 25 with unstable angina pectoris and 25 with acute myocardial infarction).

RESULTS

A close correlation between the two observers and small coefficients of variation were found regarding the ST-VM initial value (r = 0.99, 4.7), the ST-X maximum depression (r = 0.99, 3.2) and the QRS-VD end value (r = 0.98, 5.6). A less close correlation and higher coefficients of variation were found regarding the number of QRS-VD episodes (r = 0.94, 41.5), ST-VM episodes (r = 0.89, 37.8) and STC-VM episodes (r = 0.87, 35.1). Correlation coefficients and coefficients of variations for VCG measurements performed on two separate occasions by one observer ranged from 0.97 to 0.99 and from 18.1 to 1.8 respectively. Three (12%) of 25 patients with acute myocardial infarction did not meet the VCG infarction criterion (QRS-VD > or = 15 microVs) by both observers. In addition, five (20%) of the 25 patients with unstable angina pectoris met the VCG infarction criterion by both observers.

CONCLUSION

The inter and intraobserver variation for VCG interpretations was low, but the number of QRS-VD, ST-VM and STC-VM episodes varied between the two observers. This finding suggests that additional training may improve the results. Caution is also recommended in using VCG to rule out or establish the diagnosis of acute myocardial infarction.

Long-term octreotide therapy in growth hormone-secreting pituitary adenomas: evaluation with serial MR

PURPOSE

To compare the changes in tumor volume with length of octreotide treatment in patients with acromegaly, to analyze signal alterations of the pituitary mass during treatment, and to determine an optimal MR imaging protocol.

METHODS

Eighteen patients with growth hormone (GH)-secreting pituitary adenomas were studied with MR imaging before and during octreotide treatment. The length of follow-up was 9 to 70 months. Tumor volume, extension, and signal characteristics were evaluated.

RESULTS

The total pituitary volume decreased in 16 patients by a mean of 37%. In 11 patients the tumor could be demarcated from the normal gland, and mean tumor reduction was 51%. Most of the tumor reduction took place within the first year, but an additional effect was noted in four patients during the following 3 years. Tumor reexpansion, hemorrhage, or necrosis did not occur. Serum GH levels were effectively lowered within the first year, with slight additional reductions thereafter.

CONCLUSION

In long-term octreotide treatment of GH-secreting pituitary adenomas, tumor shrinkage occurs primarily during the first year, but effects are noted up to 4 years. The treatment may be considered an alternative to surgery in the select group of patients in whom the peripheral effects of chronic GH elevation, as determined by serum insulinlike growth factor I (IGF-I), are controlled. We suggest MR imaging with T1-weighted coronal and sagittal images at baseline and after 3 and 12 months, with additional MR imaging if GH or IGF-I levels rise during treatment. At baseline, both noncontrast and contrast-enhanced images should be obtained. Unenhanced images may be sufficient during follow-up unless tumor reexpansion occurs or surgery is anticipated.

Anticoagulant effects of low-molecular-weight heparin following thrombolytic therapy in acute myocardial infarction: a dose-finding study

The aim of the present study was to gain clinical experience with different dose levels of dalteparin, a low-molecular-weight heparin, following thrombolytic therapy in acute myocardial infarction. Compared to heparin, dalteparin has a longer half-life and a greater and highly predictable bioavailability, which would suggest dalteparin to be a convenient alternative. Twenty patients with ECG signs of acute transmural myocardial ischemia received streptokinase (1.5 million IU for 60 min) and were allocated to a control group or to open treatment with 50, 75 or 100 IU of dalteparin/kg b.w. s.c. b.i.d., starting 4 h later, for 6 days. Each group consisted of 5 patients. Except for the control group, aspirin was withheld during dalteparin treatment. Anti-factor-Xa (anti-FXa) values increased dose-dependently during the first 24 h and were maintained throughout the study period. On day 6, anti-FXa levels after 100 IU/kg b.w. were 0.79 (0.59-1.00) IU/ml (median, min.-max.) 4 h after administration of dalteparin, and 0.51 (0.34-0.82) IU/ml before the subsequent dose of dalteparin. In conclusion, our results indicate that a dalteparin dose slightly higher than 100 IU/kg b.w. is required in order to obtain the presumed therapeutic range of anti-FXa (0.6-1.0 IU/ml).

Ischemia monitoring with on-line vectorcardiography compared with results from a predischarge exercise test in patients with acute ischemic heart disease

Information from 24-hour monitoring with on-line vectorcardiography, starting immediately after admission, was compared with results from a predischarge exercise test 3-13 days after admission. A total of 169 patients with acute myocardial infarction and 73 patients with unstable angina pectoris were investigated. Patients were followed for 487 +/- 135 days. During the follow-up period, 19 patients (8%) died from cardiac causes and 34 (14%) were hospitalized for a myocardial infarction. The QRS vector difference (QRS-VD), ST change vector magnitude (STC-VM), ST vector magnitude (ST-VM), and ST vector leads X, Y, Z were monitored. Patients with ST depression on the exercise test showed higher occurrence of transient, supposedly ischemic, episodes of QRS-VD, STC-VM, and ST-VM than patients without ST depression. The sensitivity and specificity of identifying patients with ST depression at the exercise test were respectively, 71 and 47% for QRS-VD episodes, 58 and 56% for ST-VM episodes, and 55 and 65% for STC-VM episodes. The maximum ST depression at the exercise test was related to the maximum ST depression in vector lead X (r = .44, P < .001) and the number of STC-VM (r = .40, P < .001), ST-VM (r = .37, P < .001), and QRS-VD (r = .33, P < .001) episodes on the VCG. In multivariate analysis, maximum ST depression in vector lead X and STC-VM episodes were the best determinants for ST depression at the exercise test. In a Cox regression model, the optimal combination of exercise test data in patients who died from cardiac causes exhibited a global chi-square value of 20.0. The combination of these data and the number of STC-VM episodes increased the global chi-square value to 30.6. This study indicates that in patients with acute ischemic heart disease, early continuous vectorcardiographic monitoring may predict the results from a predischarge exercise test and also contributes independent prognostic information beyond that of exercise test data.

Prognostic information from on-line vectorcardiography in unstable angina pectoris

The prognostic information from 24-hour monitoring with on-line vectorcardiography (VCG) was assessed in 100 patients with a clinical diagnosis of unstable angina pectoris. ST change vector magnitude, ST vector magnitude and QRS vector difference were monitored. During a follow-up period of 343 +/- 77 days, 7 patients died from cardiac causes and 8 patients had a nonfatal myocardial infarction (MI). Thirty patients were readmitted for unstable angina pectoris and 36 were revascularized because of medical refractory angina. Univariate predictors of cardiac death or nonfatal MI included greater age, rest pain during hospitalization, previous MI, diabetes mellitus and high incidence of supposedly ischemic transient ST and QRS vector changes. In multivariate analysis, a high incidence of transient ST (p < 0.01) and QRS (p < 0.01) vector changes provided additional prognostic information beyond that of clinical and exercise test data. In conclusion, VCG monitoring during the first 24 h of hospitalization for unstable angina pectoris identifies patients with increased risk of adverse cardiac events.

Prognostic information from on-line vectorcardiography in acute myocardial infarction

The present study assesses the prognostic information from continuous on-line vectorcardiography in patients with acute myocardial infarction (AMI). A series of 203 patients with AMI were studied. Vectorcardiographic (VCG) recordings were obtained continuously for 24 hours. Analysis was performed on-line with the commercial system MIDA CoroNet. QRS vector difference (QRS-VD), ST change vector magnitude (STC-VM), and ST vector magnitude (ST-VM) were monitored. Patients were followed for 538 +/- 220 days. During follow-up, 36 patients died from cardiac causes and 38 patients had reinfarction. A significantly higher occurrence of transient VCG changes (QRS-VD, STC-VM, and ST-VM; p < 0.001) was seen in patients who died from cardiac causes or experienced either cardiac death or reinfarction at follow-up. The end value for QRS-VD was higher in patients who died from cardiac causes and correlated with the maximal value for creatine kinase when all patients were considered (r = 0.66; p < 0.001). Significantly lower mortality was seen in patients with VCG trend curves suggestive of coronary reperfusion (p < 0.01). In multivariate analysis, occurrence of transient changes in STC-VM, high QRS-VD end value, and VCG trend curves not suggestive of reperfusion gave additional prognostic information beyond that of age, gender, maximal creatine kinase value, heart size on chest x-ray, occurrence of ventricular fibrillation during hospitalization, and the inability to perform exercise tests. VCG monitoring during the first 24 hours of hospitalization for an AMI is a promising method for early detection of patients with increased risk for subsequent cardiac death or reinfarction.

Volume of pituitary macroadenomas: assessment by MRI

A phantom study was performed to assess the accuracy of MRI in volume determination of pituitary macroadenomas, using the summation of areas technique. Five phantoms, 3-4 cm in diameter, simulating pituitary macroadenomas of various shapes, were evaluated. The volume could adequately and reproducibly be determined, regardless of minor rotational variations of the phantom position. Using a three-dimensional SE sequence with 2.5 mm slices, the error was independent of the shape of the phantom and did not differ significantly from zero (less than 5%); this sequence was found to be the best of those tested. The coefficient of variation between examinations with different tilts was 2%. In a clinical part, the volume of pituitary macroadenomas was determined with the same technique on coronal two-dimensional 5 mm images and was used as a "gold standard" to which the largest transverse, sagittal, vertical, and oblique diameters, a central tumor area, and the product of the three orthogonal diameters were correlated. In interpatient comparisons the largest diameter was found to be useful, but only as a rough measure of the tumor size. The formula 0.5 x width x length x height provided a fairly adequate estimation of the tumor volume, except in the largest tumors. In intrapatient comparisons during bromocriptine treatment, the height was found to be the best of the diameters, but the central tumor area or the product of the orthogonal diameters was preferable.

Gd-DTPA-enhanced MR imaging of pituitary macroadenomas

In a study comprising 40 patients with pituitary macroadenomas, MR imaging was performed before and after administration of Gd-DTPA. Before contrast administration T1- and T2-weighted images were obtained, and after the injection, frontal and/or sagittal T1-weighted images. Tumour extension and delineation, relationship to adjacent structures, and signal intensity patterns were evaluated. Compared with pre-contrast T1-weighted images only, post-contrast images provided considerable additional information, but not infrequently this information could also be extracted from pre-contrast T2-weighted images. Post-contrast images were superior regarding the tumour relationship to the cavernous sinus and to the normal pituitary tissue. T2-weighted images were helpful in the diagnosis of degenerative changes, in particular intratumoural haemorrhage. A positive correlation was found between the T2 value (from dual echo sequences) and the degree of enhancement in areas with an appearance of solid tumour tissue, and the enhancement was significantly lower in GH-secreting tumours than in non-secreting ones. It is concluded that the use of Gd-DTPA is often justified in pituitary macroadenomas, particularly in pre-operative evaluation.