Survival benefit of tamoxifen therapy in adenocarcinoma of pancreas. A case-control study

BACKGROUND

Clinical data suggest tamoxifen may improve the survival of patients with unresectable ductal adenocarcinoma of pancreas.

METHODS

Eighty patients (50 women and 30 men) with biopsy-documented unresectable or incompletely resected ductal adenocarcinoma of the pancreas were treated with 20 mg of tamoxifen twice daily. The survival of the tamoxifen-treated group was compared with that of a case-control group of another 80 patients with pancreatic cancer, matched for age, sex, TNM stage, and bypass procedure versus biopsy.

RESULTS

The median survival times for the tamoxifen-treated group versus controls were 7 and 3 months, respectively (P < 0.0001). For women older than 60 years of age and treated with tamoxifen, the median survival time was 12 months. Multivariate analysis of the 160 patients showed that tamoxifen therapy, female sex, absence of metastases at diagnosis, and bypass procedure are all of independent prognostic significance for prolonged survival.

CONCLUSIONS

Patients with unresectable or incompletely resected ductal adenocarcinoma of pancreas may have a prolonged survival benefit while receiving tamoxifen treatment. This potential benefit is most prominent in older women.

Human monoclonal rheumatoid factor derived from rheumatoid synovial cells monospecific for rabbit IgG

Rheumatoid factors (RF) in rheumatoid arthritis (RA) are polyclonal autoantibodies directed against antigenic epitopes located in the Fc portion of the IgG molecule. Hybridoma technology has overcome the difficulty of their polyclonality, so that monoclonal RF (mRF) can be examined for their individual binding specificities and genetics. We isolated a monoclonal IgM RF secreting hybridoma (designated H4) from the rheumatoid synovial cells (RSC) of a patient with RA. H4 bound specifically with rabbit IgG (RIgG) and had no human IgG (HIgG) reactivity. By direct binding ELISA and absorption experiments, 6% of the RIgG reactive RSC RF in this patient with RA was monospecific for RIgG. H4 was tested against RIgG F(ab')2 and pFc' fragments, and bound only to the pFc' fragment (CH3 domain). Moreover, H4 mRF had high avidity for RIgG in a capture ELISA. Total RNA was extracted and the variable region heavy (VH) and light (VL) chain cDNA were amplified using polymerase chain reaction technology. Sequence analysis of the IgM RF VH and VL chain genes indicated usage of the VH26 germline gene (VhIII gene family) and a new V lambda germline gene. Our results suggest preferential use of restricted germline genes in the formation of autoantibodies in human autoimmune diseases. The pathological significance of RIgG specific RF is still unclear. However, this finding suggests that all RSC RF production may not necessarily be induced by autologous IgG.

The incidence of obstructive apneas in preterm infants with and without bronchopulmonary dysplasia

We tested the hypotheses that (1) preterm infants with bronchopulmonary dysplasia (BPD) have an increased incidence of obstructive apneas as compared to those without BPD (control) and (2) the respiratory pattern during obstructive apneas may be associated with more pronounced hypoventilation. Ventilation was measured with a flow-through system. We examined 2929 total apneas in 12 infants with BPD and 4366 apneas in 12 control infants matched for study weight (1.51 +/- 0.11 kg in the BPD group and 1.62 +/- 0.12 kg in the control group, P = 0.6) and for postconceptional age (33.3 +/- 0.8 weeks in the BPD group compared with 33.4 +/- 0.7 weeks in the control group, P = 0.6). The incidence of central apneas predominated in the BPD group (2551/2929, 87%) and in the control group (4188/4366, 96%). Obstructive apneas were more frequent in the BPD group (378/2929, 13%) than in the control group (178/4366, 4%, P = 0.004). The increased incidence of obstructive apneas in infants with BPD was observed in Quiet sleep (9.1 vs. 1.6%, P = 0.03) and in REM sleep (14.2 vs. 3.6%, P = 0.009). This increased incidence of obstructive apneas was applicable to short apneas (< 10 s, 10.9 vs. 2.7%, P = 0.003) and long apneas (> 10 s, 27.5 vs. 16.4%, P = 0.01). There were no significant changes in ventilatory pattern that could be uniquely attributed to one type of apnea. The findings suggest: (1) the great variability in the incidence of obstructive apneas reported in the literature relates, at least in part, to the clinical status of the infants and (2) ventilatory pattern is not a useful predictor of either type of apnea.

A self-governing rate buffer control strategy for pseudoconstant bit rate video coding

Video coding is a key to successful visual communications. An interframe video coding algorithm using hybrid motion-compensated prediction and interpolation is considered for coding studio quality video at a bit rate of over 5 Mb/s. Interframe coding without a buffer control strategy usually results in variable bit rates. Although packet networks may be capable of handling variable bit rates, in some applications, a constant bit rate is more desirable either for a simpler network configuration or for channels with fixed bandwidth. A self-governing rate buffer control strategy that can automatically steer the coder to a pseudoconstant bit rate is considered. This self-governing rate buffer control strategy employs more progressive quantization parameters, and constrains quantizer adjustments so that a smoother quality transition can be attained. Simulation results illustrate the performance of the pseudoconstant bit rate coder with this buffer control strategy.

Human Tcrb-V6.10 is a pseudogene with Alu repetitive sequences in the promoter region

Tcrb-V6.10 represents an abnormal human V gene with an Alu insertion in the promoter, a point mutation of a conserved Cys at position 23, and a missing nonamer within the usually conserved recombinase signal sequence. Here it is shown that b-V6.10 is found in the genome of most individuals, is normally located in the Tcrb-V locus on chromosome 7, but is not rearranged or transcribed. Thus, it is likely that the abnormal signal sequence precludes recombination and that the Alu insertion results in a disabled promoter, indicating the functional importance of the affected regions. Tcrb-V6.10 probably evolved by duplication of an ancestral Tcrb V13-V6-V5 cassette, like other members of the large b-V6 subfamily, and more recently became inactivated into a pseudogene.

The effect of acetylsalicylic acid on orthodontic tooth movement in the guinea pig

This study examined the influence of acetylsalicylic acid an inhibitor of prostaglandin synthesis, on orthodontic tooth movement induced with light spring forces in the guinea pig. The animal model was shown to permit reliable and accurate recording of tooth movement up to 28 days. Tooth movement was found to be highly correlated with spring forces, indicating that the model provided a sensitive test of the effect of aspirin on tooth movement. Aspirin was administered orally at the rate of 65 mg/kg per day in three divided doses and was found to effectively inhibit prostaglandin synthesis at the level of the bronchioles. However, aspirin did not appear to significantly affect tooth movement. Thus prostaglandins may not be the only mediators of the bone resorption associated with tooth movement induced by light orthodontic forces under these experimental conditions.

Characterization of a DNA probe for detection of Mycobacterium tuberculosis complex in clinical samples by polymerase chain reaction

We cloned and sequenced a DNA fragment from Mycobacterium tuberculosis for use in the identification of members of the M. tuberculosis complex. The DNA probe for culture confirmation had a sensitivity and a specificity of 100%. By using primers developed from this probe, the polymerase chain reaction detected 20 mycobacteria by ethidium bromide staining. This polymerase chain reaction system demonstrated 98% sensitivity and 100% specificity for detection of the M. tuberculosis complex in 200 sputum specimens.

Desferrithiocin is an effective iron chelator in vivo and in vitro but ferrithiocin is toxic

The efficacy and toxicity of the siderophore desferrithiocin (DFT), which has shown potential application in iron chelation therapy, were assessed in vivo and in vitro. DFT was evaluated in vivo in two ways: firstly, by measuring the effect of a single dose of DFT (10-100 mg/kg) on 59Fe excretion in iron-loaded rats labelled with 59Fe; and secondly, by examining the effect of the daily oral administration for 2 weeks of DFT (10-25 mg/kg/d) on the growing rat. DFT and its ferric complex, ferrithiocin (FT), were assessed in vitro from their effects on transferrin and iron uptake and mobilization from rat hepatocytes in culture using transferrin doubly labelled with 125I and 59Fe. Both oral and subcutaneous DFT were highly effective in promoting iron excretion in vivo, but showed evidence of toxicity after oral administration for 2 weeks at 25 mg/kg/d. In addition, DFT was much more effective than desferrioxamine or pyridoxal isonicotinyl hydrazone in reducing hepatocyte iron in vitro. However, FT was cytotoxic, causing membrane disruption and release of intracellular aspartate aminotransferase. It was concluded that DFT should not be considered for chronic iron chelation therapy without extensive further evaluation.

Recombinant alpha-interferon inhibits colony formation of bone marrow fibroblast progenitor cells (CFU-F)

Alpha-Interferon (IFN-alpha) has been shown to inhibit colony formation of hematopoietic progenitor cells, including colony-forming unit-granulocyte, erythroid, macrophage, megakaryocyte (CFU-GEMM), day 7 colony-forming unit granulocyte-macrophage (CFU-GM), day 14 CFU-GM, burst-forming unit erythroid (BFU-E), pluripotent stem cells (CFU-S), and colony-forming unit megakaryocyte (CFU-MK). The present study was designed to see whether IFN-alpha also has inhibitory effects on bone marrow fibroblast progenitors (CFU-F). We found that IFN-alpha exerted a significant inhibitory effect on both rabbit and human CFU-F formation. Inhibition of human marrow CFU-F formation by alpha interferon was unaffected by removal of 98% of monocytes/macrophages and T lymphocytes from light density marrow cells. This finding suggests that IFN-alpha probably exerts a direct inhibitory effects.

[Diagnostic and prognostic value of umbilical and cerebral Doppler velocimetry in intrauterine growth retardation]

The diagnostic and prognostic value of Doppler velocimetry in delayed intrauterine growth was investigated in a series of 105 abnormal pregnancies. The diagnostic value of the umbilical Doppler velocimetry, whether alone or combined with simultaneous exploration of the umbilical and cerebral vessels was very limited. In contrast, the simultaneous exploration of the umbilical and cerebral vessels was of considerable prognostic value, since with regard to the risk of fetal distress, the sensitivity was 86.6%, the specificity 80% and the positive predictive value 63%. The negative predictive value was 95% and the prevalence 28.5%. The authors' experience also confirms the prognostic seriousness of the absence of diastolic flow or of reverse flow (2 perinatal deaths out of 6 cases). The interval between the changes in Doppler velocimetry and fetal distress is variable, however, ranging from two days to three weeks or more in these cases.

Stimulation of leukotriene production and membrane translocation of 5-lipoxygenase by cross-linking of the IgE receptors in RBL-2H3 cells

Recent studies in rat basophilic leukemia cells (RBL-2H3) have shown that two pharmacological agents, ionomycin and thapsigargin, induce leukotriene C4 production and translocation of 5-lipoxygenase from cytosol to membrane, primarily by causing an influx of extracellular calcium. In the present study, we investigate the induction of these events by receptor activation. Cross-linking of high-affinity IgE receptors (Fc epsilon RI) by antigen in RBL-2H3 cells leads to leukotriene C4 production and membrane translocation of 5-lipoxygenase. As in the ionomycin-stimulated cells, leukotriene C4 production in antigen-stimulated cells is calcium-dependent since the amount of leukotriene C4 produced correlates quantitatively with the increase in intracellular free calcium concentration ([Ca2+]i). However, the increase in [Ca2+]i required for equivalent leukotriene C4 production by antigen is not as high as it is using ionomycin. In addition, no threshold [Ca2+]i level is required for leukotriene production by antigen, which is in contrast to the ionomycin stimulation that a [Ca2+]i level of 300-400 nM is required. Furthermore, antigen causes an additive increase in leukotriene C4 production in cells stimulated by the ionomycin. These results suggest that another as yet unidentified intracellular pathway acts in conjunction with Ca2+ for leukotriene synthesis in antigen-stimulated cells. Antigen stimulation causes 20-30% of the total cell 5-lipoxygenase to associate with membranes (compared with 10% in unstimulated cells) as demonstrated by enzyme activity assay and by Western Blot using antibodies to 5-lipoxygenase.(ABSTRACT TRUNCATED AT 250 WORDS)

Hepatitis D virus superinfection remains a rare occurrence in non-drug abusers in Hong Kong

Recent studies from Taiwan reported an increased prevalence of hepatitis D virus (HDV) superinfection as well as a spread of HDV infection to non-drug abusers. We examined the current prevalence of HDV superinfection in Hong Kong by testing sera from a large cohort of patients with acute and chronic hepatitis B virus (HBV) infection, collected between January 1988 and December 1990, for IgG antibody to HDV (anti-HDV). Anti-HDV was detected in 13 (93%) of 14 parenteral drug abusers who had HBV-related chronic liver disease. However, anti-HDV was detected in only one (0.15%) of 664 non-drug abusers who had chronic HBV infection and none of 31% patients with acute hepatitis B. We concluded that HDV superinfection remains a rare occurrence in non-drug abusers in Hong Kong.

Comparisons between active vs. passive end-range assessments in subjects exhibiting cervical range of motion asymmetries

OBJECTIVE

To compare cervical range of motion values following active (nonpractitioner-assisted) vs. passive (practitioner-assisted) movement of the head to end range.

DESIGN

Randomized, double-blind, within-subject comparisons.

SETTING

Cervical Ergonomics Laboratory, Palmer College of Chiropractic-West, Sunnyvale, CA.

SUBJECTS

Pain-free chiropractic college students, nearly evenly divided with respect to gender and ranging from 22-38 yr of age, were used in the study. Subjects exhibiting goniometrically determined cervical lateral-flexion or rotational passive end-range asymmetries of 10 degrees or greater were selected for experimentation.

INTERVENTION

None.

MAIN OUTCOME MEASURE

A goniometric (inclinometric) device was used for active and passive cervical end-range assessments. Active assessments were performed first, followed immediately by passive assessments in each subject.

RESULTS

Results demonstrated that the magnitudes of end-range asymmetry detected following active assessment were only about half of those observed following passive assessments. Moreover, whereas active end-range values were about 5 degrees less than passive on the most restricted side of passive movement, active end-range values were about 10 degrees less than passive on the least restricted side of passive end range.

CONCLUSIONS

These results are consistent with the notion that cortical influences mediating active movement are rather intolerant of asymmetric states involving end-range capability. This results in compensatory reductions in active movement on the side of greatest potential passive end range, thereby acting to preserve symmetry at the expense of overall range of motion. Results also suggest that measures obtained following active movement may be far more difficult to interpret than those obtained following passive assessments, particularly when information regarding possible asymmetry of end-range capability is considered to be of primary clinical and/or experimental importance.

Prognostic factors in patients with metastatic colorectal cancer receiving 5-fluorouracil and folinic acid

We have reported that 5-fluorouracil (5-FU) and folinic acid increased response rate and survival in patients with metastatic colorectal cancer. Now we have analysed prognostic factors for response, toxicity, survival and time to progression. The variables used for survival and response were treatment centre, treatment, age, sex, Eastern Cooperative Oncology Group (ECOG) performance status (PS), site of disease, previous radiotherapy, site of primary, disease-free interval, initial alkaline phosphatase (AP), albumin (A), lactate dehydrogenase (LDH) and aspartate aminotransferase (SGOT). The significant independent variables for survival were PS of 2 or more, initial albumin and SGOT, and treatment received, in order of importance. The relative risk of death when patients received 5-FU/folinic acid was 60% of that of patients receiving 5-FU alone. The variables predictive of response were treatment and PS. The variables used for analysis of toxicity were age, treatment centre, treatment, sex, tumour response, PS, number of courses, SGOT, AP and albumin. Treatment was found to be predictive of toxicity. Thus, baseline albumin and SGOT, and 5-FU/folinic acid treatment are significant determinants of survival, 5-FU/folinic acid and PS of 2 or more are major determinants of response and no clinical parameter could be identified as a predictor of toxicity.

Influx of extracellular calcium is required for the membrane translocation of 5-lipoxygenase and leukotriene synthesis

Our studies assessed the effects of increases in intracellular calcium concentrations [( Ca2+]i) on leukotriene synthesis and membrane translocation of 5-lipoxygenase (5LO). The calcium ionophore ionomycin and the tumor promoter thapsigargin stimulated leukotriene production and translocation of 5-lipoxygenase to the membrane. Both agents elicited prolonged rises in [Ca2+]i. Leukotriene C4 production associated with [Ca2+]i in cells stimulated with various concentrations of ionomycin and thapsigargin suggests that a threshold [Ca2+]i level of approximately 300-400 nM is required. In the absence of extracellular Ca2+, both the ionomycin- and thapsigargin-induced rises in [Ca2+]i were transient, indicating that the prolonged [Ca2+]i elevation is due to an influx of extracellular Ca2+. Addition of EGTA to the external medium before, or at different times during, the treatment with ionomycin or thapsigargin instantaneously inhibited 5LO translocation and leukotriene synthesis, indicating that Ca2+ influx plays an essential role in 5LO membrane translocation and leukotriene synthesis. No leukotriene production was detected when cells were stimulated by a physiological stimulus of leukotriene D4. The addition of 100 nM leukotriene D4 triggered peak rises in [Ca2+]i that were comparable to those achieved by the ionomycin and thapsigargin. However, the leukotriene D4 induced rise was transient and rapidly declined to a lower but still elevated steady-state level, which was attributed to Ca2+ influx. Stimulation with 100 nM leukotriene D4 for 15 s increased the cellular levels of 1,4,5-inositol triphosphate (IP3), 1,3,4-IP3, and 1,3,4,5-inositol tetraphosphate (IP4).(ABSTRACT TRUNCATED AT 250 WORDS)

Preservation techniques for heart transplantation: comparison of hypothermic storage and hypothermic perfusion

Preservation of the donor heart is an important and controversial subject in heart transplantation. This study compares simple hypothermic storage and hypothermic perfusion in a swine model of heart transplantation (n = 14). The donor hearts of group A (n = 7) were placed in simple hypothermic storage for 5 hours. The donor hearts of group B (n = 7) were placed onto a perfusion apparatus for 5 hours, with pressure maintained at 28 cm of H2O and a myocardial temperature of 8 to 10 degrees C. In both groups the hearts were initially protected with isosmolar potassium cardioplegic solution. The perfusate in group B contained moderate sodium, mannitol, glucose, insulin, and oxygen. The ischemic interval within both groups was 6 hours including orthotopic transplantation. Investigation was conducted at three time periods: prepreservation, postpreservation, and immediately after loading. For both groups there was nonsignificant depression of myocardial function (cardiac index, stroke index, stroke work index, ejection fraction, and wall stress) at the postpreservation period. After volume loading, for the hypothermic perfusion group there was significant improvement of myocardial function (cardiac index, p less than 0.01; stroke index, p less than 0.01) with no significant change in heart rate, systemic vascular resistance, and systolic blood pressure. There was also significant improvement in myocardial performance (p less than 0.05) for the hypothermic perfusion group after volume loading. Ultrastructural changes were minimal for both groups, and there were no major heart transplantation after 6 hours of ischemia; however, hearts retain their contractile capacity better after hypothermic perfusion than after simple hypothermic storage.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of isoproterenol on right and left atrial dynamics and plasma atrial natriuretic factor in anesthetized rabbits

The effect of isoproterenol on mean right and left atrial pressures (RAP, LAP) and dimensions (RAD, LAD), and plasma immunoreactive atrial natriuretic factor (IR-ANF) was investigated in anesthetized rabbits. Infusion of isoproterenol (10 micrograms.kg-1.min-1 for 10 min) significantly increased plasma IR-ANF and heart rate. There were no significant changes in mean RAP or LAP following isoproterenol. Neither mean RAD, systolic RAD and diastolic RAD nor mean LAD, systolic LAD or diastolic LAD changed significantly. Systolic right and left atrial wall stress and diastolic right and left atrial wall stress did not change significantly during the infusion of isoproterenol. Since atrial dimensions did not increase, it is unlikely that the release of IR-ANF in response to isoproterenol is mediated by atrial stretch. These results suggest that the release of IR-ANF in response to this dose of isoproterenol is mediated by factors other than stretch or changes in atrial dynamics.

R-verapamil decreases anti-estrogen resistance in a breast cancer model

Drug resistance eventually limits the effectiveness of antiestrogens in breast cancer treatment. Pharmacological reversal of this refractoriness has been attempted with R-Verapamil, a well tolerated calcium channel blocker. This drug significantly decreased the incidence of lung foci after intravenous seeding of the R3230AC rat adenocarcinoma; this effect was correlated with reduction in the expression of P-glycoprotein. The simultaneous administration of antiestrogens with a non-toxic enantiomer of Verapamil was beneficial in the tumour model investigated.