Asymmetry of the mean-variability tradeoff raises questions about the model in investigations of individual bioequivalence

Tradeoff between changes of intraindividual variations of 2 drug formulations and of the difference between their means is a characteristic of a procedure suggested for the determination of individual bioequivalence [Schall and Luus 1993] and to be proposed by the Food and Drug Administration for adoption. Hauck et al. [1996] investigated properties of the tradeoff. Their procedure was applied and extended in the present study. The tradeoff was shown to be asymmetric. Notably, a small change in intrasubject variations can elicit, under various conditions, a comparatively large change in the allowable difference between means which can still be compatible with the declaration of bioequivalence. For instance, when the intraindividual coefficients of variations are 40% and 38% for the reference and test formulations, respectively, the allowable difference between means may increase, as a benefit, by 12.3%. A penalty by 11.2% is elicited if the intrasubject variations of the reference and test products are 40 and 42%, respectively. In addition, 4-period crossover trials were simulated. Ratios of estimated variances of the 2 formulations followed an F-distribution. Distributions of changes in allowable deviations between means were calculated from the tradeoff relationships; generally substantial changes were noted with high probabilities. For example, with an intraindividual variation of 30% there is an estimated 37% probability that a benefit of 10% increase, or larger, is gained by chance in the allowable difference between means, and an additional 36% probability that a penalty of a 10%, or larger, decrease in the allowable difference is suffered. With an intrasubject variation of 40%, the estimated probabilities are 42% and an additional 42% for a 10% expansion and contraction, respectively, of the allowable difference between means. Consequently, the strong asymmetry of the tradeoff could result in very large probabilities for benefits and penalties. Therefore, the investigated model assessing individual bioequivalence does not appear to be suitable for implementation.

Structural models of the transmembrane region of voltage-gated and other K+ channels in open, closed, and inactivated conformations

A large collaborative, multidisciplinary effort involving many research laboratories continues which uses indirect methods of molecular biology and membrane biophysics to analyze the three-dimensional structures and functional mechanisms of K+ channels. This work also extends to the distant relatives of these channels, including the voltage-gated Na+ and Ca2+ channels. The role that our group plays in this process is to combine the information gained from experimental studies with molecular modeling techniques to generate atomic-scale structural models of these proteins. The modeling process involves three stages which are summarized as: (I) prediction of the channel sequence transmembrane topology, including the functionality and secondary structure of the segments; (II) prediction of the relative positions of the transmembrane segments, and (III) filling in all atoms of the amino acid residues, with conformations for energetically stabilized interactions. Both physiochemical and evolutionary principles (including sequence homology analysis) are used to guide the development. In addition to testing the steric and energetic feasibilities of different structural hypotheses, the models provide guidance for the design of new experiments. Structural modeling also serves to "fill in the gaps" of experimental data, such as predicting additional residue interactions and conformational changes responsible for functional processes. The modeling process is currently at the stage that experimental studies have definitely confirmed most of our earlier predictions about the transmembrane topology and functionality of different segments. Additionally, this report describes the detailed, three-dimensional models we have developed for the entire transmembrane region and important functional sites of the voltage-gated Shaker K+ channel in the open, closed, and inactivated conformations (including the ion-selective pore and voltage-sensor regions). As part of this effort, we also describe how our development of structural models for many of the other major K+ channel families aids in determining common structural motifs. As an example, we also present a detailed model of the smaller, bacterial K+ channel from Streptomyces lividans. Finally, we discuss strategies for using newly developed experimental methods for determining the structures and analyzing the functions of these channel proteins.

Enhanced expression of anti-apoptotic proteins in human papillomavirus-immortalized and cigarette smoke condensate-transformed human endocervical cells: correlation with resistance to apoptosis induced by DNA damage

Apoptosis plays an important role in various biological processes including embryogenesis, differentiation, homeostasis, and oncogenesis. We have developed a system composed of primary human endocervical cells (HEN), HEN immortalized by human papillomavirus (HPV) type 16, and their counterparts subsequently malignantly transformed by cigarette smoke condensate (CSC). To understand the role of apoptosis in the multistep oncogenesis of human cervical cells, we examined the expression of apoptosis-associated proteins in our in vitro model system. The results showed no significant difference in the levels of apoptosis-inducing proteins bak and bax among all the cell types examined. On the other hand, the levels of apoptosis-inhibiting proteins bcl-2, bcl-xL and BAG-1 increased progressively after immortalization and transformation. The p53 protein level decreased in the HPV16-immortalized HEN and increased in one of two lines of the CSC-transformed HEN. Further, the increased levels of apoptosis-inhibiting proteins in the HPV16-immortalized and the CSC-transformed HEN correlated with progressively increased resistance of these cells to apoptosis induced by staurosporine or cisplatin. This study provided the first evidence that overexpression of apoptosis-inhibiting proteins is important for both multistep oncogenesis and resistance of human endocervical cells to apoptosis induced by DNA-damaging reagents.

[Effects of Yunqitang on both esophageal mucosal morphology and esophageal motility in reflux esophagitis patients]

OBJECTIVE

To observe the effects of Yunqitang (YQT) on both esophageal mucosal morphology and esophageal motility in patients with reflux esophagitis (RE).

METHODS

According to Syndrome Differentiation of TCM, 42 RE patients were divided into three groups: Disharmony of Liver and Stomach (D) group, Deficiency-Cold of Spleen and Stomach (DC) group, Heat Syndrome caused by depression of Liver Qi (H) group. No. I, II, III of YQT were taken respectively for 4 weeks. Before and after treatment scores of typical symptoms were collected, gastroscope and esophageal motility were measured.

RESULTS

(1) The symptom remission rate was 81.1%, there were significant differences between the group DC with group D and Group H (P < 0.01). (2) The esophageal mucosal healing rate was 61.9%, the effective rate was 90.5%, and the ineffective rate 9.5%. There weren't significant difference of effective rates among the three groups (P < 0.05). (3) The changes of esophageal motility: lower esophageal sphictor pressure (LESP), average peristaltic pressure (APP) of group D were higher (P < 0.05), LESP, gastro-esophageal barrier pressure (GEBP) and peristaltic conduct speed (PCS) of group DC were remarkably higher (P < 0.05), GEBP of group H was improved (P < 0.05).

CONCLUSIONS

YQT has a good therapeutical effect, it's not only resolving reflux symptoms, healing esophageal mucosa, but also improving esophageal motile function.

[Study on expression of Evi1 and MDS1-Evi1 genes in myelodysplastic syndromes]

OBJECTIVE

To investigate expression of Evi1 and MDS1-Evi1 genes in myelodysplastic syndromes (MDS) and its role in pathogenesis of MDS.

METHODS

Expression of Evi1 and MDS1-Evi1 genes was examined in 31 MDS, 11 post MDS acute myeloid leukemia (post MDS AML) and 34 de novo AML patients by a semi-quantitative RT-PCR.

RESULTS

Evi1 expression was not detected in 8 normal controls, but low MDS1-Evi1 expression levels (MDS1-Evi1/GAPDH < 0.1) detected in 3 of the 8 controls. Evi1 mRNA was expressed in 1 of 8 RA, 8 of 13 RAEB and 6 of 9 RAEB-t patients, and the percentage of Evi1 expression in RAEB(t) patients was higher than that in RA(P < 0.05). MDS1-Evi1 expression was detected in 5 of 8 RA, 9 of 13 RAEB and 5 of 9 RAEB-t patients, and MDS1-Evi1 expression levels (MDS1-Evi1/GAPDH > 0.1) in the patients were markedly higher than those in the controls. Evi1 expression was gradually increased in 4 of 5 RAEB-t patients with transformation from MDS to AML. The percentages of Evi-1 and MDS1-Evi1 expression in post MDS AML patients were higher than those in de novo AML (P < 0.01 and P < 0.05, respectively). The numbers of colony formation of progenitor cells in Evi1 and MDS1-Evi1-positive MDS patients were decreased as compared with Evi1 and MDS1-Evi1-negative patients.

CONCLUSION

Abnormal expression of Evi1 and overexpression of MDS1-Evi1 might play a certain role in the pathogenesis or progression of MDS and post MDS AML.

Rhodopsin transgenic pigs as a model for human retinitis pigmentosa

PURPOSE

To further characterize the retinas of Pro3471Leu rhodopsin transgenic pigs, a model for human retinitis pigmentosa.

METHODS

Retinas from normal and transgenic pigs, newborn to 20 months old, were processed for light and electron microscopic immunocytochemical examination.

RESULTS

At birth, rod numbers were normal in the transgenic retinas, but their outer segments were short and disorganized and their inner segments contained stacks of rhodopsin-positive membranes. The newborn rod synapses lacked synaptic vesicles and ribbons and had numerous rhodopsin-positive, filopodia-like processes that extended past the cone synapses into the outer plexiform layer. Rod cell death was apparent by 2 weeks and was pronounced in the mid periphery and central regions by 6 weeks. Far peripheral rods were initially better preserved, but by 9 months virtually all rods had degenerated. Cones degenerated more slowly than rods, but by 4 weeks the cone synapses were shrunken and some mid peripheral cones had lost their immunoreactivity for phosphodiesterase-gamma, arrestin, and recoverin. From 9 months to 20 months, the cone outer segments shortened progressively, and more cones lost immunoreactivity for these proteins.

CONCLUSIONS

The rhodopsin transgenic pig retina shares many cytologic features with human retinas with retinitis pigmentosa and provides an opportunity to examine the earliest stages in photoreceptor degeneration, about which little is known in humans. The finding of abnormal rhodopsin localization in newborn rods is consistent with misrouting of mutant rhodopsin as an early process leading to rod cell death. Novel changes in the photoreceptor synapses may correlate with early electrophysiological abnormalities in these retinas.

Treatment of locally recurrent rectal carcinoma--results and prognostic factors

PURPOSE

To assess the local control and survival in patients who received pelvic irradiation for locally recurrent rectal carcinoma.

METHODS AND MATERIALS

The records of 519 patients with locally recurrent rectal carcinoma treated principally with external-beam radiation therapy between 1975 to 1985 at a single institute were retrospectively reviewed. These included 326 patients who relapsed locally following previous abdominoperineal resection, 151 after previous low anterior resection, and 42 after previous local excision or electrocoagulation for the primary. No patients had received adjuvant radiation therapy or chemotherapy for the primary disease. Concurrent extrapelvic distant metastases were found in 164 (32%) patients at local recurrence and, in the remaining 355, the relapse was confined to the pelvis. There were 290 men and 229 women whose age ranged from 23 to 91 years (median = 65). Median time from initial surgery to radiation therapy for local recurrence was 18 months (3-138 months). Radiation therapy was given with varying dose-fractionation schedules, total doses ranging from 4.4 to 65.0 Gy (median = 30 Gy) over 1 to 92 days (median = 22 days). For 214 patients who received a total dose > or = 35 Gy, radiation therapy was given in 1.8 to 2.5 Gy daily fractions.

RESULTS

The median survival was 14 months and the median time to local disease progression was 5 months from date of pelvic irradiation. The 5-year survival was 5%, and the pelvic disease progression-free rate was 7%. Twelve patients remained alive and free of disease at 5 years after pelvic irradiation. Upon multivariate analysis, overall survival was positively correlated with ECOG performance status (p = 0.0001), absence of extrapelvic metastases (p = 0.0001), long intervals from initial surgery to radiation therapy for local recurrence (p = 0.0001), total radiation dose (p = 0.0001), and absence of obstructive uropathy (p = 0.0013). Pelvic disease progression-free rates were positively correlated with ECOG performance status (p = 0.0001), total radiation dose (p = 0.0001), and previous conservative surgery for the primary (p = 0.02).

CONCLUSIONS

Survival is poor for patients who develop local recurrence following previous surgery for rectal carcinoma. Pelvic radiation therapy provides only short-term palliation, and future efforts should be directed to the use of effective adjuvant therapy for patients with rectal carcinoma who are at high risk of local recurrence.

The role of ras gene mutation in gastric cancer and precancerous lesions

Abnormality of ras gene family was studied in a total of 206 cases of gastric cancer and precancerous lesions by PCR-RFLP, PCR-SSCP and DNA sequencing. The results showed that mutation rate of H-ras 12 codon in metaplasia, atypical hyperplasia, early-stage cancer and advanced cancer was 16.7%, 31.2%, 50.0%, and 32.2%, respectively. In the groups of superficial gastritis and normal controls, no mutation were detected in codon 12 of ras. Mutations of H-ras 61 codon and N-ras 12 codon in various groups were the same as those in normal control. K-ras 12 codon mutation was detected in only 2 cases of gastric cancer by using PCR-SSCP, but it was not detected by DNA sequencing, which may be polymorphism. All H-ras 12 codon mutations were G-->T mutation. There were significant difference between the groups of metaplasia, dysplasia, gastric carcinoma and normal control group (P < 0.05, P < 0.01, P < 0.01, respectively). It was concluded that H-ras 12 codon mutation was an early event and may play an important role in gastric carcinogenesis. Although K-ras, N-ras mutation rates are high in colon cancer and leukemia, it seems to bear no relationship with gastric cancer.

Immunophenotype of myeloid cells in myelodysplastic syndromes and its clinical implications

OBJECTIVE

To explore the immunophenotype of myeloid cells in myelodysplastic syndyomes (MDS) and its clinical implications.

METHODS

A panel of monoclonal antibody was used to detect CD13+, CD33+, CD15+ and CD14+ antigens on the membrane surfaces of myeloid cells in the bone marrow from 51 MDS, 21 aplastic anemia (AA), 21 paroxysmal nocturnal hemoglobinuria (PNH) patients. 10 acute myeloblastic leukemia (AML) patients and 15 normal subjects by immunoenzymatic assay. The morphology and chromosome karyotype of bone marrow cells of MDS patients were also examined.

RESULTS

CD14+, CD13+ and CD33+ cells in the bone marrow were more in MDS patients than in normal controls, AA patients and PNH patients. CD15+ cells in the bone marrow were less in MDS patients than in normal controls.

CONCLUSIONS

The percentages of CD14+, CD13+ and CD33+ positive cells in the bone marrow of MDS patients were related to the percentage of myeloblasts, the chromosomal aberrations and the response to treatment. It indicated that there is immunophenotypic misexpression of myeloid cells in MDS patients. Immunophenotype analysis of myeloid cells might be useful for the diagnosis and treatment of MDS patients.

[Study on T lymphocyte recognition of tumor antigens on autologous CML cells]

OBJECTIVE

To investigate the existence of cytotoxic precursor cells in previously untreated or remissive chronic myelogenous leukemia(CML) patients,and identify their phenotypical and functional characteristics.

METHODS

Bone marrow or peripheral blood mononuclear cells from CML patients were stimulated with autologous CML cells by using mixed lymphocyte tumor cell coculture.

RESULTS

A kind of cytotoxic T lymphocytes could be generated from bone marrow or peripheral blood of CML patients. These T cells showed differential cytotoxicities against autologous and allogeneic CML cells and no activity to autologous and allogeneic normal bone marrow cells. They also exhibited no inhibitive effect on CFU-GM yields. LAK cells had no effect on autologous CML cells, but showed intensive cytotoxic activity to allogeneic CML cells. The T lymphocytes obtained were CD3+ CD56+ non-MHC restricted or CD3+ CD56- MHC restricted. HLA-DR and CD25 were expressed in a significantly larger proportion of T lymphocytes stimulated with autologous CML cells than those not stimulated. The T lymphocytes showed low proliferative response to autologous CML cell stimulation and no or least response to allogeneic CML cells, they showed also no response to EB virus-transformed autologous B cells(obtained in remission) pulsed with peptides corresponding to the BCR-ABL joining region.

CONCLUSION

There is probably a common tumor antigen among CMLs, this leukemia-specific antigen can be recognized by T cells,and it shows no indication to be a p210 fusion sequence.

Interobserver variation in prostate cancer Gleason scoring: are there implications for the design of clinical trials and treatment strategies?

A series of prostate cancer histological slides from 71 patients were used to measure the interobserver variation among three pathologists awarding a Gleason score. The study was prompted on account of the use of histological grade to stratify patients prior to randomization within two clinical trials currently recruiting at our centre, and a proposed study that would allocate treatment depending upon the score awarded. The pathologists were expected to award a score based upon their day to day experience, there being no consensus meeting before-hand to agree on the grey areas of the Gleason grading system. We used the kappa statistic to assess the level of agreement. This was calculated both for comparison of the raw scores awarded by the three observers, as well as the grouped scores corresponding to those groupings used for the purposes of stratification in the two trials. The extent of the interobserver variation (weighted kappa) for the raw scores (Gleason scores 2-10) was 0.16 to 0.29 and for the grouped scores (Gleason scores < or = 7 or > or = 8), kappa was 0.15 to 0.29. For the raw scores, the total agreement rate was 9.9% and the total disagreement 26.8%; for the grouped scores the total agreement rate was 43.7%. It is concluded that, despite this level of agreement there is no concern regarding stratification using the Gleason score, because of the subsequent randomization. However, using a reported Gleason score to determine treatment might be inappropriate. These data indicate the value of a central review process for pathology grading in clinical trials, especially where the treatment is directly affected by this information.

Predicting the outcome of postasphyxial hypoxic-ischemic encephalopathy within 4 hours of birth

OBJECTIVE

To build models that predict severe adverse outcome within 4 hours of birth in patients with postasphyxial hypoxic-ischemic encephalopathy. The goal was to develop models for selecting patients for therapeutic trials of neuroprotective medications.

STUDY DESIGN

Retrospective cohort study with follow-up to a minimum age of 12 months of 164 "outborn" term infants admitted to a tertiary neonatal intensive care unit, and 14 "inborn" term infants in the two tertiary perinatal centers in a regionalized setting. After performing univariate screening tests, multivariate models of association between risk factors and "severe adverse outcome" (death or major neurosensory impairment) were constructed.

RESULTS

Of 178 infants with postasphyxial hypoxic-ischemic encephalopathy of defined severity admitted consecutively between 1985 and 1992, 48 died, 40 survived with major neurosensory impairment, and 13 were lost to follow-up. The important predictors of severe adverse outcome in the first 4 hours were delayed onset of breathing, administration of chest compressions, and seizures. At 60 minutes of age, based on predicted probabilities of > 0.50, the sensitivity of the predictive model was 85% and specificity 68%. The parameter estimates of the predictive models are reported.

CONCLUSIONS

Age of onset of breathing, administration of chest compressions, and age of onset of seizures were the most important variables predictive of adverse outcome in this study. Although fairly sensitive and specific, these predictive models should be applied with caution. To build more accurate models, a template for the conduct of a large, multicenter prospective study is provided.

Molecular dynamics study of free energy profiles for organic cations in gramicidin A channels

The free energy profiles for four organic cations in right-handed single-helix gramicidin A dimers were computed by using umbrella sampling molecular dynamics with CHARMM. Ion-water column translocations were facilitated by using a novel "water-tunnel" approach. The overlapping pieces of free energy profile for adjacent windows were selected from three trajectories that differed in initial ion rotation and were aligned by the method of umbrella potential differences. Neglected long-range electrostatic energies from the bulk water and the bilayer were computed with DelPhi and added to the profile. The approach was corroborated for the formamidinium-guanidinium pair by using perturbation dynamics at axial positions 0, 6, 12, and 15 A from the channel center. The barrier to ethylammonium entry was prohibitive at 21 kcal/mol, whereas for methylammonium it was 5.5 kcal/mol, and the profile was quite flat through the channel, roughly consistent with conductance measurements. The profile for formamidinium was very similar to that of methylammonium. Guanidinium had a high entry barrier (deltaF = +8.6 kcal/mol) and a narrow deep central well (deltaF = -2.6 kcal/mol), qualitatively consistent with predictions from voltage-dependent potassium current block measurements. Its deep central well, contrasting with the flat profile for formamidinium, was verified with perturbation dynamics and was correlated with its high propensity to form hydrogen bonds with the channel at the dimer junction (not shared by the other three cations). Analysis of the ensemble average radial forces on the ions demonstrates that all four ions undergo compressive forces in the channel that are at maximum at the center of the monomer and relieved at the dimer junction, illustrating increased flexibility of the channel walls in the center of the channel.

Genetically engineered large animal model for studying cone photoreceptor survival and degeneration in retinitis pigmentosa

Patients with retinitis pigmentosa (RP) typically develop night blindness early in life due to loss of rod photoreceptors. The remaining cone photoreceptors are the mainstay of their vision; however, over years or decades, these cones slowly degenerate, leading to blindness. We created transgenic pigs that express a mutated rhodopsin gene (Pro347Leu). Like RP patients with the same mutation, these pigs have early and severe rod loss; initially their cones are relatively spared, but these surviving cones slowly degenerate. By age 20 months, there is only a single layer of morphologically abnormal cones and the cone electroretinogram is markedly reduced. Given the strong similarities in phenotype to that of RP patients, these transgenic pigs will provide a large animal model for study of the protracted phase of cone degeneration found in RP and for preclinical treatment trials.

Improvement in total positioning error for lateral prostatic fields using a soft immobilization device

PURPOSE

To prospectively measure the total positioning error present in lateral pelvic fields of patients undergoing prostatic irradiation, and to evaluate the effect of a rigid table insert and soft immobilization on the magnitude of the measured error.

MATERIALS AND METHODS

Sixty-one consecutive patients receiving radical prostatic irradiation with a four field technique underwent a total of 234 lateral portal films during the first, third, fifth and seventh week of treatment. The position of the isocentre was compared to the isocentre on the corresponding simulator films and the magnitude and direction of deviations recorded. The patients were divided in to three cohorts of 15 patients, 15 patients and 31 patients. The first cohort was treated on a standard treatment couch, the second cohort treated with the table top stiffened using a 1 cm polycarbonate insert, and the third cohort treated with a soft immobilization device supporting the lower legs, and the polycarbonate insert.

RESULTS

There was no difference in the mean deviation of the vector of the isocentre displacement in the y and z directions identified at any of the four times when measurements were taken during therapy between the cohorts treated with or without the polycarbonate insert, but without immobilization. The overall mean deviation for these first two cohorts of patients was 3.9 mm. The positioning of patients treated with immobilization was compared to those treated without, and the immobilized patients had a significantly improved overall mean deviation of 2.6 mm (P = 0.002). This was a result of improvement in both the random and systematic components of the total error. In addition, the proportion of errors greater than 5 mm was reduced from 17% of set-ups to 8% of set-ups. The time during the course of treatment when the measurement was taken had no effect on positioning error for any of the treatment groups.

CONCLUSION

Stiffening the treatment couch with a 1 cm thick polycarbonate insert had no effect on reducing total positioning error, but immobilization with an inexpensive and non-customized foam rubber leg support reduced total positioning error in a statistically significant way.

[Detection of ras gene mutation in various stages of gastric cancer by PCR/RFLP SSCP and DNA sequencing]

Investigate mutation of ras gene family in various stage of gastric cancer in China. PCR-RFLP, PCR-SSCP and PCR-DNA sequencing were used to detect mutation rates of H-ras, K-ras and N-ras gene. Mutation rates of H-ras at 12 codon in metaplasia, atypical hyperplasia, and progressive gastric cancer is 16.7% (6/36), 31.2% (15/48), 34.7% (25/72), respectively. In groups of superficial gastritis and normal control, no mutation were found. Mutations of H-ras 61 codon and N-ras 12 codon in various groups were the same as normal. Only 2 cases of K-ras 12 codon mutation were detected in gastric cancer by PCR-SSCP, but it was not identified by DNA sequencing. It may be of polymorphism. All H-ras 12 codon mutation were G-->T mutation. There are significant difference between groups of metaplasia, dysplasia, and gastric carcinoma comparing with group of normal control (P < 0.05, P < 0.01, P < 0.01). H-ras 12 codon mutation maybe an early event and maybe play important role in gastric carcinogenesis. Although K-ras mutation rate is high in colon cancer and leukemia it seemed to be relationship with gastric cancer. High frequency of H-ras 12 codon mutation maybe the characteristic of gastric cancer and associate with high incidence of gastric cancer in China. Three methods used in this experiment were compared that SSCP method is more sensitive than RFLP and cold SSCP is simpler and likely to be used in clinic.

High-affinity CCK-A receptors on the vagus nerve mediate CCK-stimulated pancreatic secretion in rats

Cholecystokinin (CCK) receptors are found on vagal afferent fibers. In pancreatic acini, CCK receptors exist in high- and low-affinity states. The aim of this study was to identify the vagal CCK-A receptor affinity state that mediates the effect of CCK on pancreatic protein secretion. Using a rat model with a pancreatic-biliary cannula, we studied the effects of CCK-JMV-180 on exocrine pancreatic function. CCK-JMV-180 acts as an agonist on high-affinity CCK receptors and as an antagonist on low-affinity CCK receptors. Infusion of CCK-JMV-180 (22-88 micrograms.kg-1.h-1) caused dose-dependent increases in pancreatic protein secretion, which were blocked by the CCK-A receptor antagonist L-364,718. Acute vagotomy in anesthetized rats and perivagal application of capsaicin in conscious rats abolished pancreatic responses to CCK-JMV-180 at 22 and 44 micrograms.kg-1.h-1. CCK-JMV-180 did not reduce pancreatic responses to CCK octapeptide infusion at 20 and 40 pmol.kg-1.h-1. To demonstrate that endogenously released CCK also acts on high-affinity CCK-A receptors, we showed that in conscious rats intraduodenal infusion of 18% casein produced a threefold increase in protein secretion and elevated plasma CCK levels from 0.7 to 8.4 pM. Infusion of CCK-JMV-180 at 44 micrograms.kg-1.h-1 failed to inhibit pancreatic responses to casein. In separate studies, perivagal application of 1% capsaicin inhibited 95% and 90% of the pancreatic responses to casein and casein combined with intravenous CCK-JMV-180, respectively. The neurotoxic effect of capsaicin on small-diameter sensory vagal fibers was verified by immunohistochemical and retrograde tracing studies. In conclusion, we demonstrated that in contrast to their effect on satiety, which is mediated by vagal low-affinity CCK-A receptors, exogenous CCK and endogenous CCK under physiological conditions act through high-affinity CCK-A receptors to mediate pancreatic protein secretion. These findings suggest that different affinity states of the vagal CCK receptors mediate different digestive functions.

[The killing effect of IL-2 and IFN-alpha activated bone marrow on K562 leukemic cell]

OBJECTIVE

To evaluate the killing effect of IL-2 and IFN-alpha activated bone marrow cells on K562 cells.

METHODS

Semi-solid colony assay was used.

RESULTS

Bone marrow from leukemia patients in remission was activated in vitro with IL-2 for 3 days. The activated bone marrow (ABM) displayed killing effects of 0.31 approximately 2.30 logs on K562 cells, this killing effects was further increased to 0. 30 approximately > 3.15 logs when IFN-alpha added with IL-2 to the marrow for activation. IL-2 alone or in combination with IFN-alpha showed no inhibition of CFU-GM and K562 cells. Compared with IL-2 or IFN-alpha alone, the combination of the two cytokines could more effectively maintain the killing effect of ABM on leukemic cells.

CONCLUSION

IFN-alpha can augment the purging effect of IL-2 ABM and combination of the two cytokines can effectively maintain the cytotoxicity of ABM.

[Effects of IFN-alpha on the expressions of perforin and granzymes in IL-2 activated lymphocytes]

OBJECTIVE

To study the effect of IFN-alpha on the expressions of perforin and granzymes in IL-2-activated-lymphocytes.

METHODS

NK and LAK activities were assayed by 4 hour standard 51Cr release test, the activity of perforin was detected by hemolysis method, expression of granzyme B was measured by ABC immunohistological method, expression of granzyme A was measured by BLT method.

RESULTS

IFN-alpha significantly augmented the activities of NK and LAK in IL-2 activated peripheral blood lymphocytes (PBL) after 1 day culture. Perforin activity in lymphocytes was increased after 1 day exposure to IL-2 or IFN-alpha, and was enhanced when exposed to the combination of IL-2 and IFN-alpha. After 3 day culture, the perforin activity remained high in lymphocytes activated by IL-2 alone or in combination with IFN-alpha, while declined to control level in IFN-alpha exposed group. IL-2 and IFN-alpha alone or in combination had no effect on expression of granzyme A and B.

CONCLUSION

IFN-alpha enhances the cytotoxicity of lymphocytes activated by IL-2. The mechanism might be that IFN-alpha upregulates the perforin expression.

Quality of life following bone marrow transplantation: a comparison of patient reports with population norms

All surviving patients who had received an allogeneic bone marrow transplant at the Princess Margaret Hospital were asked to participate in a health-related quality of life (HQL) study using the Medical Outcomes Survey-Short Form 36 (MOS SF-36), the Satisfaction with Life Domains Scale-Bone Marrow Transplantation (SLDS-BMT) and a current symptoms checklist. The main objective was to compare the health status of BMT survivors with age-adjusted population norms. Of the 251 patients contacted, 93% returned questionnaires. The median follow-up after BMT was 40 months, ranging from 1-253 months. On average, survivors had some diminished HQL relative to the health status of the population in general. Time since transplant had a significant influence on HQL; those less than 3 years from transplant experienced considerable impairment while those who had survived beyond this point were indistinguishable from the normal population in most domains and significantly better in certain psychosocial aspects of health. Many patients still reported symptoms months after BMT; some were mildly affected while others experienced more troublesome symptoms. However, 81% of patients were satisfied with the HQL outcome that they had achieved and 94% would recommend a transplant for someone in similar circumstances.

Anatomic considerations of the lumbar isthmus

STUDY DESIGN

A morphometric study of lumbar isthmus from L1 to L5 on 30 dried lumbar spines was conducted.

OBJECTIVE

To provide anatomic data about the lumbar isthmus and to quantitatively evaluate structural features of the lumbar isthmus and its relationship to adjacent anatomic structures.

SUMMARY OF BACKGROUND DATA

There are very few anatomic studies about the lumbar isthmus, and no study describes the relationship of the lumbar isthmus to its adjacent structures.

METHODS

Direct measurements using digital calipers and a goniometer were taken from 30 dried lumbar spines. Anatomic evaluation focused on the lumbar isthmus and its related structures, the isthmus pedicle, and superior and inferior facets. Seven linear and four angular parameters of the lumbar isthmus were determined.

RESULTS

The length of the superior edge of the isthmus gradually increased from L2 to L5 (from 8.22 +/- 1.43 mm at L2 to 10.44 +/- 1.90 mm at L5), and that of its inferior edge progressively decreased from L2 to L5 (from 8.67 +/- 1.76 mm at L2 to 6.34 +/- 1.74 mm at L5). The superoinferior diameter of the isthmus decreased from L3 to L5 (from 13.87 +/- 1.77 mm at L3 to 13.26 +/- 2.49 mm at L5). The superior edge of the isthmus was the thinnest at L4 (1.62 +/- 0.58 mm), and its thickness inferiorly increased from L1 to L5 (from 6.71 +/- 1.47 mm at L1 to 7.76 +/- 1.08 mm at L5). The medial and caudal inclination of the isthmus with respect to the pedicle gradually increased from L1 to L5 (from 112.3 degrees +/- 13.8 degrees at L1 to 119.2 degrees +/- 11.2 degrees at L5 medial inclination and from 132.5 degrees +/- 8.8 degrees at L2 to 139.0 degrees +/- 12.1 degrees at L5 caudal inclination, respectively). The dimensions of the lumbar isthmus were positively correlated to dimensions of the pedicle and orientations of the facets.

CONCLUSIONS

This study provides detailed anatomic data of the lumbar isthmus. Anatomic parameters of the lumbar isthmus are related to the vertebral levels and have a significant correlation with the angles of the facets and the dimensions of the pedicles. The vulnerability of the pars interarticularis of the fifth lumbar vertebra has been anatomically confirmed.

[Clonal analysis of blood cells using X-linked HUMARA gene polymorphism]

OBJECTIVE

To explore the method for clonal analysis of blood cells.

METHODS

Thirty female AML patients and 20 normal female subjects were analysed by the analysis of X-linked HUMARA gene polymorphism and methylation pattern.

RESULTS

The heterozygote rate of HUMARA gene in Chinese women was 88% and the gene had a stable methylation pattern. Out of 20 control females, 17 were heterozygotes and among them 15 were polyclonal, 2 (11.8%) showed skewed X-inactivation. All heterozygote AML were clonal hematopoiesis.

CONCLUSION

HUMARA gene polymorphism is a good marker for clonality analysis of blood cells.

Lack of influence of sequence of top-up doses on repair kinetics in rat spinal cord

BACKGROUND AND PURPOSE

The rat spinal cord model was used to determine whether repair kinetics changed during a course of fractionated radiotherapy if twice daily doses were given either at the initial or final period of a concomitant boost irradiation schedule.

MATERIALS AND METHODS

The rat cervical spinal cord was irradiated from C2-T2 in 870 animals with top-up doses of three daily fractions of 9 Gy representing 75% of the biologic dose at the ED50 level for white matter necrosis. To simulate concomitant boost protocols, these top-up doses were given either preceding (initial top-up) or following (final top-up) a b.i.d. schedule of 1 Gy/F delivered at 0, 1, 2, 4, 8 or 24 h interfraction intervals. The end point was forelimb paralysis secondary to white matter necrosis.

RESULTS

For interfraction intervals of 0, 1, 2, 4, 8 and 24 h, the initial top-up schedules yielded ED50 values of 18.2, 19.2, 23.7, 21.3, 27.2 and 29.7 Gy, respectively; the corresponding ED50s from the final top-up schedules were 17.5, 19.0, 20.7, 21.2, 26.9 and 30.3 Gy, respectively. A 10% reduction in the ED50 value from pooled data was observed when the interfraction interval was reduced from 24 (ED50 = 30.3 Gy) to 8 h (ED50 = 27.1 Gy). Fitting the incomplete repair (IR) version of the LQ model with mono-exponential repair kinetics gave alpha/beta values of 1.4 and 1.5 Gy, and similar repair half-times of 4.3 and 5.0 h for the initial and final top-up experiments, respectively. The IR model with bi-exponential repair kinetics did not provide a better fit to the data.

CONCLUSIONS

We conclude that the sequence of top-up doses has no apparent influence on radiation sensitivity or repair kinetics in the rat spinal cord. The clinical implication is that the interfraction interval but not the timing of the boost is a critical determinant of spinal cord tolerance in concomitant boost protocols.

[Study on the immunophenotype of myeloid cells in myelodysplastic syndromes and its clinical implications]

OBJECTIVE

To explore the immunophenotype of myeloid cells in myelodysplastic syndromes and its clinical implications.

METHODS

A panel of monoclonal antibodies was used to detect CD13, CD33, CD15 and CD14 on the membrane surfaces of myeloid cells in the bone marrow from 51 patients with myelodysplastic syndromes (MDS), 21 with aplastic anemia (AA), 21 with paroxysmal nocturnal hemoglobinuria (PNH), and 15 normal subjects, by immunoenzymatic assay. The morphology and chromosome karyotype of bone marrow cells of MDS patients were also examined.

RESULTS

CD14+ cells, CD13+ cells and CD33+ cells in the bone marrow were more in MDS patients than in normal controls, AA patients and PNH patients. CD15+ cells in the bone marrow were less in MDS patients than in normal controls. The percentages of CD14, CD13 and CD33 positive cells in the bone marrow of MDS patients were related to the percentage of myeloblast, the chromosomal aberrations and the response to treatment.

CONCLUSION

There was an immunophenotypic misexpression of myeloid cells in MDS patients. Immunophenotype analysis of myeloid cells might be useful for the diagnosis and directing treatment in MDS patients.