Hepatic arterial floxuridine and leucovorin for unresectable liver metastases from colorectal carcinoma. New dose schedules and survival update

BACKGROUND

We studied three new dose schedules of hepatic arterial infusion of floxuridine (FUDR) and leucovorin and update survival analysis of a previously reported trial using these drugs by hepatic arterial infusion for patients with hepatic metastases from colorectal carcinoma.

METHODS

Untreated patients with hepatic metastases from colorectal cancer were treated with three dose schedules: Group D, FUDR (0.3 mg/kg/day) and leucovorin (30 mg/m2/day) as a 14-day continuous infusion through an implantable hepatic arterial pump alternating with a 4-week rest period; Group E, a lower dose of FUDR (0.25 mg/kg/day) and leucovorin (30 mg/m2/day) as a 14-day infusion alternating with 2 weeks of saline; and Group F, FUDR (0.3 mg/kg/day) with a lower leucovorin dose (15 mg/m2/day) for 2 weeks followed by a 2-week rest.

RESULTS

In 42 patients with unresectable hepatic metastases, the complete-plus-partial response rate was 56%, with a median survival of 24.2 months. Complete-plus-partial response rates for groups D, E, and F were 30%, 54%, and 75%, respectively. Twelve percent of the 42 patients developed biliary sclerosis; the percentages of patients per group were 17%, 15%, and 6%, respectively. Updated median survival of the original 24 patients treated with FUDR and leucovorin by hepatic arterial infusion and these 42 new patients (66 total) was 28.8 months. One-, two-, three-, four-, and five-year survival rates were 86%, 62%, 31%, 15%, and 7%, respectively.

CONCLUSIONS

Hepatic arterial chemotherapy with FUDR and leucovorin for patients with hepatic metastases from colorectal carcinoma yields a high response rate and 1- and 2-year survivals of 86% and 62%, respectively. Although a lower dose of leucovorin (15 mg/m2) with FUDR produces a high response rate with less toxicity, before larger scale trials are initiated, further investigation is needed to reduce toxicity. A study of hepatic arterial dexamethasone with FUDR and leucovorin has been initiated for this purpose.

Light scattering from a sliced target through use of the internal field of infinite cylinders: comparison between Mie theory and a sliced sphere

Light scattering from a particle that can be sectioned into circular slices is calculated by performing a coherent integration of the internal field over the volume of the target. The internal field in each slice is taken to be the internal-field solution of an infinite cylinder of radius equal to the radius of the slice. It is shown that for a spherical scatterer with size parameters up to 1.4, the integration leads to results that are in good agreement with those predicted by the Mie theory. Thus, we show the remarkable result that the internal field from an infinite cylinder can reproduce scattering intensities for such a radically different shape as a sphere. This being the case, a wide variety of target shapes between a sphere and a cylinder should be open to evaluation by this technique. The approach also has the benefit of being computationally efficient, requiring a double integration of the internal field over a disk and then coherently adding these calculations. The computations demonstrated in this paper are performed relatively quickly on a computer such as the Macintosh Centris 650, and this efficiency allows us to obtain the scattered fields for many target shapes.

Defective T cell receptor signaling and CD8+ thymic selection in humans lacking zap-70 kinase

We have previously described a type of selective T cell deficiency (STD) characterized by persistent infections reminiscent of severe combined immunodeficiency. We show here that STD patients carry a mutation of zap-70, resulting in loss of the activity of this kinase. The thymi of zap-70-/- patients show the presence of CD4+CD8+ cells in the cortex; however, only CD4, not CD8, single-positive cells are present in the medulla. Peripheral CD4+ T cells from the zap-70-/- patients exhibit markedly reduced tyrosine phosphorylation, fail to produce interleukin-2, and do not proliferate in response to T cell receptor stimulation by mitogens or antigens. Thus, Zap-70 kinase appears to be indispensable for the development of CD8 single-positive T cells as well as for signal transduction and function of single-positive CD4 T cells.

The effect of breast-feeding frequency on serum bilirubin levels

OBJECTIVE

Our purpose was to evaluate the effect of breast-feeding frequency on serum bilirubin levels in the first 3 days after birth.

STUDY DESIGN

Two hundred seventy-five infants were randomly assigned to a frequent or demand breast-feeding schedule.

RESULTS

Infants in the frequent group (n = 131) nursed nine (7.5 to 10.5) times per day (median and inner 80%), and the demand group (n = 143) fed 6.5 (5.5 to 8.0) times per day. The serum bilirubin level was measured in all infants between 48 and 80 hours (median 53 hours, inner 80% 48 to 68 hours) and was 7.4 (1.8 to 10.7) mg/dl in the frequent group and 8.0 (2.9 to 11.2) mg/dl in the demand group (p = 0.103). There was no correlation between the frequency of breast-feeding and the serum bilirubin level.

CONCLUSION

Within the range of the frequency of nursing observed in this study, we could not demonstrate a significant effect on serum bilirubin levels in the first 3 days after birth.

Identification of a T cell-specific transcriptional enhancer 3' of the human T cell receptor gamma locus

Positive and negative transcriptional regulatory mechanisms are thought to play a major role in the expression of T cell antigen receptor (TCR) genes. Since the alpha beta and gamma delta T cell receptor heterodimers are expressed in a mutually exclusive fashion and since TCR genes are sequentially activated during T cell ontogeny, transcriptional activation and repression must at least in part determine T lineage-specific and developmental-specific expression of these genes. We have identified a transcriptional enhancer located 6.5 kb downstream from the human T cell receptor gamma (TRG) locus. The nucleotide sequence of the enhancer core element shows strong sequence homology to the recently identified murine C gamma 1 enhancer. The enhancer demonstrates T cell-specific activity, but not gamma delta sublineage-specificity in combination with either a heterologous or gene-specific promoter. Thus, additional regulatory elements may be required to repress the expression of rearranged TRG genes in non-gamma delta T cells.

Preoperative 5-fluorouracil, low-dose leucovorin, and concurrent radiation therapy for rectal cancer

BACKGROUND

A Phase I trial was performed to determine the maximum tolerated dose of concurrent preoperative radiation therapy (5040 cGy) and 2 cycles (bolus daily times 5) of 5-fluorouracil (5-FU) and low-dose leucovorin (LV) (20 mg/m2), followed by surgery and 10 cycles of postoperative 5-FU/LV in patients with primary or recurrent rectal cancer.

METHODS

Twenty-four patients were entered into the study. Preoperatively, the initial dose of 5-FU was 325 mg/m2. 5-FU was escalated 50 mg/m2, while the dose of LV and radiation therapy remained constant. Chemotherapy and radiation began concurrently on day 1. The postoperative chemotherapy was not dose escalated; 5-FU, 425 mg/m2, and LV, 20 mg/m2. The median follow-up was 10 months (range, 4-19 months).

RESULTS

The resectability rate with negative margins in the 23 patients who underwent surgery was 100%. One patient refused surgery. The pathologic complete response rate was 13% (3 of 23). An additional four patients had negative nodes and a microscopic foci of tumor in the bowel wall. Therefore, the total clinical complete response rate was 30% (7 of 23). The maximum tolerated dose of 5-FU for the preoperative combined modality segment was 375 mg/m2; therefore, the recommended Phase II dose level is 325 mg/m2. The incidence of Grade 3+ toxicity for the 22 patients treated at the recommended 5-FU dose level (325 mg/m2) during the preoperative combined modality segment was as follows: diarrhea, 14%; erythema, 5%; hematologic, 10%; and total, 18%. The median nadir counts were leukocyte count, 3.7 (range, 1.5-5.9); hemoglobin count, 12.2 (range, 10.2-14.3); and platelet count (times 1000), 165 (range, 92-237).

CONCLUSIONS

With this regimen, the recommended doses of chemotherapy in the combined modality segment are slightly higher than those recommended in arm 2 of the Intergroup postoperative adjuvant rectal trial 0114. This regimen will serve both as the preoperative arm of the Intergroup randomized trial of preoperative versus postoperative combined modality therapy for resectable rectal cancer (INT R9401) as well as the basis for the combined modality segment of NSABP RO-3.

Hepatic arterial floxuridine and leucovorin for unresectable liver metastases from colorectal carcinoma. New dose schedules and survival update

BACKGROUND

We studied three new dose schedules of hepatic arterial infusion of floxuridine (FUDR) and leucovorin and update survival analysis of a previously reported trial using these drugs by hepatic arterial infusion for patients with hepatic metastases from colorectal carcinoma.

METHODS

Untreated patients with hepatic metastases from colorectal cancer were treated with three dose schedules: Group D, FUDR (0.3 mg/kg/day) and leucovorin (30 mg/m2/day) as a 14-day continuous infusion through an implantable hepatic arterial pump alternating with a 4-week rest period; Group E, a lower dose of FUDR (0.25 mg/kg/day) and leucovorin (30 mg/m2/day) as a 14-day infusion alternating with 2 weeks of saline; and Group F, FUDR (0.3 mg/kg/day) with a lower leucovorin dose (15 mg/m2/day) for 2 weeks followed by a 2-week rest.

RESULTS

In 42 patients with unresectable hepatic metastases, the complete-plus-partial response rate was 56%, with a median survival of 24.2 months. Complete-plus-partial response rates for groups D, E, and F were 30%, 54%, and 75%, respectively. Twelve percent of the 42 patients developed biliary sclerosis; the percentages of patients per group were 17%, 15%, and 6%, respectively. Updated median survival of the original 24 patients treated with FUDR and leucovorin by hepatic arterial infusion and these 42 new patients (66 total) was 28.8 months. One-, two-, three-, four-, and five-year survival rates were 86%, 62%, 31%, 15%, and 7%, respectively.

CONCLUSIONS

Hepatic arterial chemotherapy with FUDR and leucovorin for patients with hepatic metastases from colorectal carcinoma yields a high response rate and 1- and 2-year survivals of 86% and 62%, respectively. Although a lower dose of leucovorin (15 mg/m2) with FUDR produces a high response rate with less toxicity, before larger scale trials are initiated, further investigation is needed to reduce toxicity. A study of hepatic arterial dexamethasone with FUDR and leucovorin has been initiated for this purpose.

Culture and schizophrenia: the DOSMD challenge

The World Health Organization's International Pilot Study on Schizophrenia (IPSS) and subsequent Determinants of Outcomes of Severe Mental Disorder (DOSMD) studies have reported that the course of schizophrenia is more favourable in 'developing' than 'developed' societies. The 1992 DOSMD study attributes this difference to culture. We review studies concerning the course of schizophrenia and conclude that the evidence for a more favourable course in developing societies is not conclusive. Indeed, a favourable course has also been reported in various industrialised societies. We also raise questions about the findings reported in the recent DOSMD study, including the conclusion that the putatively more favourable course is a product of culture. Finally, we argue that longitudinal, direct observation of patients in their natural environments must be carried out before variations in the course of schizophrenia can be adequately understood.

Preoperative 5-fluorouracil, low-dose leucovorin, and concurrent radiation therapy for rectal cancer

BACKGROUND

A Phase I trial was performed to determine the maximum tolerated dose of concurrent preoperative radiation therapy (5040 cGy) and 2 cycles (bolus daily times 5) of 5-fluorouracil (5-FU) and low-dose leucovorin (LV) (20 mg/m2), followed by surgery and 10 cycles of postoperative 5-FU/LV in patients with primary or recurrent rectal cancer.

METHODS

Twenty-four patients were entered into the study. Preoperatively, the initial dose of 5-FU was 325 mg/m2. 5-FU was escalated 50 mg/m2, while the dose of LV and radiation therapy remained constant. Chemotherapy and radiation began concurrently on day 1. The postoperative chemotherapy was not dose escalated; 5-FU, 425 mg/m2, and LV, 20 mg/m2. The median follow-up was 10 months (range, 4-19 months).

RESULTS

The resectability rate with negative margins in the 23 patients who underwent surgery was 100%. One patient refused surgery. The pathologic complete response rate was 13% (3 of 23). An additional four patients had negative nodes and a microscopic foci of tumor in the bowel wall. Therefore, the total clinical complete response rate was 30% (7 of 23). The maximum tolerated dose of 5-FU for the preoperative combined modality segment was 375 mg/m2; therefore, the recommended Phase II dose level is 325 mg/m2. The incidence of Grade 3+ toxicity for the 22 patients treated at the recommended 5-FU dose level (325 mg/m2) during the preoperative combined modality segment was as follows: diarrhea, 14%; erythema, 5%; hematologic, 10%; and total, 18%. The median nadir counts were leukocyte count, 3.7 (range, 1.5-5.9); hemoglobin count, 12.2 (range, 10.2-14.3); and platelet count (times 1000), 165 (range, 92-237).

CONCLUSIONS

With this regimen, the recommended doses of chemotherapy in the combined modality segment are slightly higher than those recommended in arm 2 of the Intergroup postoperative adjuvant rectal trial 0114. This regimen will serve both as the preoperative arm of the Intergroup randomized trial of preoperative versus postoperative combined modality therapy for resectable rectal cancer (INT R9401) as well as the basis for the combined modality segment of NSABP RO-3.

Acute care visits and rehospitalization in women and infants after cesarean birth

This study, conducted as a randomized clinical trial, focuses on acute care visits and rehospitalizations of mothers whose infants were delivered by cesarean section (n = 122) and infants (n = 123) for 8 weeks after hospital discharge. There were three maternal rehospitalizations. Maternal acute care visits were for wound infections or complications (27 of 34); 21 occurred in the first 4 weeks. Seventy-five percent of infant rehospitalizations were for infection or possible infection; 22 of 31 infant acute care visits occurred in first 4 weeks for bilirubin checks and infant care problems, and 21 of 25 visits in weeks 5 to 8 were for infections. Discharge teaching and home care in first 4 weeks after discharge and issues related to infant infections in the second 4-week period may reduce the need for rehospitalizations and acute care visits in both mothers who had cesarean section and their infants.

Expansion of CD3+CD4-CD8- T cell population expressing high levels of IL-5 in Omenn's syndrome

Omenn's syndrome is a fatal, autosomal-recessive combined immune deficiency characterized by several erythematous exfoliative eruptions, lymphadenopathy, hepatosplenomegaly, and elevated eosinophil count. In some of these patients an expansion of CD3+CD4-CD8- double negative (DN) T cell population was observed. We show here that the DN population represents a clonal expansion of T cells which preferentially use V beta 14 in their T cell receptor complex. Using polymerase chain reaction, we show that patient's DN cells express spontaneously high levels of IL-5, thus possibly explaining the abundance of eosinophils in this disorder. The increase of IgE observed in patients with Omenn's syndrome is unlikely to be related to IL-4 production, as IL-4 levels in patient samples were low. However, patient's low expression of interferon-gamma (IFN-gamma), which has been reported to inhibit IgE production, may explain the elevated levels of IgE in this patient. The results thus highlight the importance of the inhibitory effect of IFN-gamma on regulation of IgE production.

Immunoradiometric assay of thyrotropin during the first six months of life

The aim of this preliminary study was to assess variation in thyrotropin (thyroid-stimulating hormone; TSH) levels using an immunoradiometric assay during the first 6 months of life of normal infants. One hundred and five normal newborns (59 females, 46 males) were evaluated for TSH, triiodothyronine and thyroxine at 48 h of life, and TSH was additionally determined at 15 days (n = 42), 30 days (n = 38), 60 days (n = 24), 90 days (n = 28), and 180 days (n = 30). Complete determinations during the total period of the study were obtained in 17 infants. Samples corresponding to the 48-hour period did not exhibit a normal distribution. In this group, percentile 3 corresponded to 0.9 mU/l, the median to 4.2 mU/l and percentile 97 to 17.7 mU/l. Levels of TSH similar to those of the normal adult population were reached between 30 and 60 days of life. Nevertheless, TSH levels of some of the children remained at higher values for a longer period. In summary, our results suggest that high TSH levels might not always indicate an underlying pathology. A critical evaluation of the normality criteria could avoid unnecessary studies and treatments.

Sturge-Weber syndrome associated with a large left hemispheric arteriovenous malformation

A patient with the characteristic changes of Sturge-Weber syndrome on the right side was found to have a large arteriovenous malformation on the left side which involved the superior ophthalmic vein. This association, although previously reported, is extremely rare.

Causes and mechanisms of territorial and nonterritorial cerebellar infarcts in 115 consecutive patients

BACKGROUND AND PURPOSE

Territorial cerebellar infarcts have mainly a thromboembolic mechanism. Cerebellar infarcts less than 2 cm in diameter have recently been reported as nonterritorial infarcts, but it is not clear whether they are low-flow or embolic infarcts. The aim of the present study was to compare the characteristics and causes of territorial and nonterritorial infarcts in a prospective series of 115 patients.

METHODS

We collected data from 115 consecutive patients with cerebellar infarcts (79 territorial and 36 nonterritorial [ie, less than 2 cm]), using magnetic resonance imaging (88 patients) and computed tomography.

RESULTS

Patients with territorial infarcts and those with nonterritorial infarcts had similar vascular risk factors and clinical presentations and an equal frequency of cardiac source of embolism (32% versus 42%; P = NS) and of large artery occlusive disease (23% versus 19%; P = NS). Occlusive lesions of large arteries at angiography occurred at the level of one cerebellar artery (5% versus 0%; P = NS) and proximal to the ostia of the cerebellar arteries (18% versus 19%; P = NS). Infarcts distal to occlusive lesions were subdivided into unilateral vertebral artery occlusive disease (presumed artery-to-artery embolic mechanism; 18% versus 5%; P = NS) and low-flow state distal to bilateral vertebral or basilar artery occlusion (presumed hemodynamic mechanism; 0% versus 14%; P = .004). Patients with nonterritorial infarcts had more frequent hypercoagulable state (17% versus 1.25%; odds ratio, 15.6 [95% confidence interval, 1.8 to 135]). For the remaining patients, the mechanism of the infarct was unknown (34% versus 22%; P = NS).

CONCLUSIONS

Cerebellar infarcts less than 2 cm in diameter (ie, nonterritorial) have the same high rate of embolic mechanism as territorial infarcts (47% versus 49%; P = NS), have more frequent hypercoagulable state, and sometimes have a hemodynamic mechanism.

Genetic and molecular analyses of the C-terminal region of the recE gene from the Rac prophage of Escherichia coli K-12 reveal the recT gene

The nucleotide sequence of the C-terminal region of the recE gene of the Rac prophage of Escherichia coli K-12 reveals the presence of a partially overlapping reading frame we call recT. Deletion mutations show that recT is required for the RecE pathway of conjugational recombination. By cloning recT with a plasmid vector compatible with pBR322, we showed by cis-trans tests that the portion of the recE gene encoding ExoVIII DNA nuclease activity is also required for RecE pathway conjugational recombination. The recT gene can replace the redB gene of lambda for recA-independent plasmid recombination. A Tn10 insertion mutation previously thought to be in recE is located in recT and is renamed recT101::Tn10. Discrepancies between the molecular mass estimates of wild-type ExoVIII protein determined from mobility in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and calculated from the predicted amino acid sequence are discussed. The hypothesis that wild-type ExoVIII protein results from fusion of RecE and RecT proteins is disproved genetically, thus supporting a previous hypothesis that the discrepancies are due to abnormal protein mobility in SDS-PAGE. A computer-performed scan of the bacteriophage nucleotide sequence data base of GenBank revealed substantial similarity between most of recE and a 2.5-kb portion of the b2 region of lambda. This suggests interesting speculations concerning the evolutionary relationship of lambda and Rac prophages.

Cerebral infarction due to painless thoracic aortic and common carotid artery dissections

BACKGROUND

Aortic arch dissection is usually lethal unless emergency surgery is performed. The dissection rarely may have a benign outcome or may occur without pain and be revealed by cerebral infarction. It is then likely to be seen primarily by a neurologist. In such cases, the value of new noninvasive diagnostic testing has not been reported.

CASE DESCRIPTION

A 51-year-old man had a sudden left-sided hemiplegia due to hemorrhagic capsular and caudate infarcts on the right side. Cervical ultrasound examination with color flow imaging showed a bilateral common carotid artery dissection extending up to the bifurcation. Transesophageal echocardiography showed an aortic arch dissection, involving the innominate and left common carotid artery origins, which was confirmed by magnetic resonance imaging and aortography. The patient spontaneously fully recovered and is still alive 24 months after the stroke onset.

CONCLUSIONS

This case emphasizes the usefulness of new noninvasive techniques such as transesophageal echocardiography and color-coded Doppler echocardiography in the diagnosis and follow-up of painless dissection of aortic and common carotid arteries. This cause of stroke may be underestimated.

Leukemoid reaction induced by prenatal administration of betamethasone

A case of leukemoid reaction in a premature baby whose mother was antenatally treated by betamethasone is reported. The neonatal and maternal factors which might lead to leukocytosis or leukemoid reaction were excluded. The presented case is the last in a series of eight previously reported cases of leukemoid reaction, in which the common denominator was the antenatal administration of betamethasone.

Atrial septal aneurysm and patent foramen ovale as risk factors for cryptogenic stroke in patients less than 55 years of age. A study using transesophageal echocardiography

BACKGROUND AND PURPOSE

An association between atrial septal aneurysm and embolic events has been suggested. Atrial septal aneurysm has been shown to be associated with patent foramen ovale and, in some reports, with mitral valve prolapse. These two latter cardiac disorders have been identified as potential risk factors for ischemic stroke. The aim of this prospective study was to assess the role of atrial septal aneurysm as an independent risk factor for stroke, especially for cryptogenic stroke.

METHODS

We studied the prevalence of atrial septal aneurysm, patent foramen ovale, and mitral valve prolapse in 100 consecutive patients < 55 years of age with ischemic stroke who underwent extensive etiological investigations. We compared these results with those in a control group of 50 consecutive patients. The diagnosis of atrial septal aneurysm and patent foramen ovale relied on transesophageal echocardiography with a contrast study and that of mitral valve prolapse, on two-dimensional transthoracic echocardiography.

RESULTS

Stepwise logistic regression analysis showed that atrial septal aneurysm (odds ratio, 4.3; 95% confidence interval, 1.3 to 14.6; P = .01) and patent foramen ovale (odds ratio, 3.9; 95% confidence interval, 1.5 to 10; P = .003) but not mitral valve prolapse were significantly associated with the diagnosis of cryptogenic stroke. The stroke odds of a patient with both atrial septal aneurysm and patent foramen ovale were 33.3 times (95% confidence interval, 4.1 to 270) the stroke odds of a patient with neither of these cardiac disorders. For a patient with atrial septal aneurysm of > 10-mm excursion, the stroke odds were approximately 8 times the stroke odds of a patient with atrial septal aneurysm of < 10 mm.

CONCLUSIONS

This study shows that atrial septal aneurysm and patent foramen ovale are both significantly associated with cryptogenic stroke and that their association has a marked synergistic effect. Atrial septal aneurysms of > 10-mm excursion are associated with a higher risk of stroke.

Asymmetries in visual search for conjunctive targets

Asymmetry is demonstrated between conjunctive targets in visual search with no detectable asymmetries between the individual features that compose these targets. Experiment 1 demonstrated this phenomenon for targets composed of color and shape. Experiment 2 and 4 demonstrate this asymmetry for targets composed of size and orientation and for targets composed of contrast level and orientation, respectively. Experiment 3 demonstrates that search rate of individual features cannot predict search rate for conjunctive targets. These results demonstrate the need for 2 levels of representations: one of features and one of conjunction of features. A model related to the modified feature integration theory is proposed to account for these results. The proposed model and other models of visual search are discussed.

Congenital bilateral juvenile granulosa cell tumor of the ovary in leprechaunism: a case report

We report on a case of leprechaunism. In addition to the typical clinical and biochemical features, a bilateral juvenile granulosa cell tumor of the ovaries and cytomegalovirus hepatitis were found. The granulosa cell tumor may result from the mitogenic effect of insulin at high concentration, which acts via a mechanism mediated by insulin-like growth factor I receptors.

Accuracy and reproducibility of left ventricular mass measurement by subcostal M-mode echocardiography in hypertensive patients and professional bicyclists

In some patients, left ventricular (LV) mass cannot be evaluated by M-mode echocardiography because the parasternal long-axis view is not available. The aim of this study was to determine whether the subcostal view obtained by M-mode echocardiography under 2-dimensional guidance allows accurate and reproducible LV mass determination. Using the cube formula, LV mass was calculated, from parasternal and subcostal views in 96 subjects: 73 hypertensives and 23 professional bicyclists, covering a wide range of LV dimensions. M-mode tracings were read by 2 experienced echocardiographers and the interobserver variability was evaluated. With use of the subcostal view, the interobserver reproducibility, expressed as observer 1-observer 2, was excellent: -0.3 +/- 1.3 mm for LV diastolic diameter, -0.1 +/- 1.0 mm for ventricular diastolic septal thickness, 0.2 +/- 0.6 mm for diastolic free wall thickness and 0.03 +/- 16.7 g for LV mass. In 96% of cases, the difference in LV mass between the 2 observers did not exceed 30 g. With use of the parasternal and subcostal approaches, LV mass was not statistically different (202.6 +/- 2.2 g and 206.5 +/- 2.0 g, respectively) and the difference was < 52 g (clinically significant threshold) in 91 of 96 cases. It is concluded that, using the cube formula, LV mass calculation based on the subcostal view was accurate and not statistically different from that provided by the usual parasternal approach.

ECG compression using long-term prediction

A new algorithm for ECG signal compression is introduced. The compression system is based on the subautoregression (SAR) model, known also as the long-term prediction (LTP) model. The "periodicity" of the ECG signal is employed in order to further reduce redundancy, thus yielding high compression ratios. The suggested algorithm was evaluated using an in-house database. Very low bit rates on the order of 70 b/s are achieved with a relatively low reconstruction error (percent rms difference-PRD) of less than 10%. The algorithm was compared, using the same database, with the conventional linear prediction (short-term prediction--STP) method, and was found superior at any bit rate. The suggested algorithm can be considered a generalization of the recently published average beat subtraction method.