An evaluation of the accuracy of magnetic-resonance-guided Gamma Knife surgery

An evaluation of the systematic accuracy of magnetic resonance (MR)-guided Gamma Knife surgery was performed. In two experiments, a cylinder phantom filled with dosimeter gel containing ferrous sulfate was fixed to a stereotactic frame. The gel phantom was irradiated with the Gamma Knife with a single shot using 4-mm collimators. The target point was set at the frame center of the stereotactic system giving coordinate values of X = 100, Y = 100, Z = 100. The maximum target dose was 15 Gy. MR imaging was undertaken immediately after the irradiation, using a superconductive 1.5-T MR scanner. Spin echo T1-weighted images, with transaxial, coronal, and sagittal views, were obtained. On the images, points with the highest signals were defined as the target point which received the maximum dose. Within the dose range of the experiment, this definition is based on a linear relationship between the dose to the gel and the T1 relaxation shortening after irradiation. The distances between the frame center and the target point defined on the MR images in the experiments were 0.12 mm (0.2375 pixels) and 0.43 mm (0.8515 pixels), respectively. Both are within the mechanical accuracy of the Gamma Knife. The imaging study confirms the accuracy of the Gamma Knife surgery used in the institution.

Interaction of cationic liposomes with cells of electrically active neuronal networks in culture

Incubation of rhodamine-labeled cationic liposomes with mature murine spinal cultures results in strong fluorescence that is evenly distributed on somata and neurites of neurons in 7 different cultures. Staining of the glial carpet is minimal. Rhodamine-labeled dextran, encapsulated in liposomes, also stains neurons. Electron microscope data show external attachment and intact internalization of liposomes. Spontaneous electrical bursting activity is altered but not lost after incubation.

Inference for the association between coefficients in a multivariate growth curve model

This paper generalizes the work of Blomqvist (1977, Journal of the American Statistical Association 72, 746-749) on inference for the relationship between the individual-specific slope and the individual-specific intercept in a linear growth curve model. The paper deals with longitudinal data involving one or more response variables and irregular follow-up times, with each response variable postulated to follow a linear growth curve model. The problem considered is inference concerning the association between one growth curve coefficient and another--for example, the slope and intercept for a selected response variable, or the two slopes for two different response variables--after adjusting for all remaining coefficients among all of the response variables. An inferential approach based on the method of moments and an inferential approach based on maximum likelihood are described, and the asymptotic properties of these procedures are presented. Extensions of the methodology to allow polynomial growth curves and baseline covariates are outlined. The methodology is illustrated with a practical example arising from a clinical trial in lung disease.

The use of neuronal networks on multielectrode arrays as biosensors

Mammalian spinal neuronal networks growing on arrays of photoetched electrodes in culture provide a highly stable system for the long-term monitoring of multichannel, spontaneous or evoked electrophysiological activity. In the absence of the homeostatic control mechanisms of the central nervous system, these networks show remarkable sensitivities to minute chemical changes and mimic some of the properties of sensory tissue. These sensitivities could be enhanced by receptor up-regulation and altered by the expression of unique receptors. The fault-tolerant spontaneous network activity is used as a dynamic platform on which large changes in activity signify detection of chemical substances. We present strategies for the expression of novel supersensitivities to foreign molecules via genetic engineering that involves the grafting of ligand binding cDNA onto truncated native receptor DNA and the subsequent expression of such chimeric receptors.

[The prognostic value of focusylated alpha-fetoprotein measurement in liver cancer patients after surgery]

Postoperative change of focusylation index (FI) of serum alpha-fetoprotein (F-AFP) and the result of surgery were studied in 34 patients of hepatocellular carcinoma. In 23 patients, serum F-AFP was disappeared with serum AFP turning negative and no tumor recurrence heppaned within the first 6 months postoperatively. In 4 patients, owing to hepatitis or active cirrohosis in the remained liver, serum AFP didn't turn negative, but FI of AFP was obviously decreased, follow-up found no signs of tumor recurrence within the first 6 months. In 5 of 7 patients, with decreased postoperative serum AFP levels and unchanged FI, tumor recurred. These results showed that postoperative F-AFP monitoring is helpful in evaluating surgical efficacy in liver tumor producing AFP.

[The experimental study of anti-human AFP variant McAb in radioimmuno-detection and radioimmuno-therapy of human hepatocellular carcinoma model in nude mice]

Anti-human AFP variant monoclonal antibody (AFP-R-LCA McAb) was labeled by 131I and injected intraperiton ealy. The 131I-AFP-R-LCA McAb was gathered in tumor of nude mice bearing human hepatocellular carcinoma (HCC). The tumor/liver radioactivity redio was 5.2, but normal mice IgG labeled by 131I-(131-mIgG) or free 131I was not gathered in tumor and distributed everywhere in average. The group of 131I-AFP-R-LCA McAb was positively visualized by gamma camea. The test showed that 131I-AFP-R-LCA McAb cured the nude mice bearing HCC. The tumor inhibition rate in 131I-AFP-R-LCA McAb group at the 4th week after treatment was significantly higher than those of the other groups (85%, 45%, 20%, 7% respectively, P < 0.05). The result showed that the AFP-R-LCA McAb have strong affinity and special combination to HCC cells and it can be recognized as a carrier for radioimmunodetection and radioimmunotherapy.

Point mutations in the chloroplast 16s rRNA gene confer streptomycin resistance in Nicotiana plumbaginifolia

In a previous paper we reported the isolation of streptomycin-resistant mutants from Nicotiana plumbaginifolia and presented evidence for chloroplast control of the resistance trait. To understand the molecular basis of the resistance in these mutants, we sequenced three regions in the chloroplast 16s rRNA gene, which correspond to the 5' terminus, the 530 loop, and the 900 stem/loop of Escherichia coli 16s rRNA, and compared them with the sequences of the wild-type. Our results show that: (1) nine mutants have a C to T change at position 912, (2) one mutant (SR1021) has a G to A change at position 885, (3) one mutant has a C to T change at position 526, based on E. coli numbering; and (4) three mutants do not have any change in the regions analyzed. The point mutation detected in SR1021 has not been reported previously. In E. coli 16s rRNA, position 885 is protected from chemical probing by ribosomal protein S12 and is closely juxtaposed with the streptomycin-binding region (positions 912-915) in the predicted secondary structure. It is likely that the G to A transition at this position is a novel mutation for streptomycin resistance.

Use of surrogate information time for monitoring the effect of treatment on the change in a response variable in clinical trials

We discuss the monitoring of clinical trials data and propose two surrogates for total information for use with the spending function approach where there are repeated measurements and we wish to compare the rates of change in a response variable under different treatments. These surrogates are applied to a setting similar to the Lung Health Study. Although the surrogates do not require estimation of the variance parameters, they do require some knowledge of the ratio R of the within- to the between-individual variances. The effects of overestimating and underestimating R are illustrated. In situations of uncertainty we recommend overestimating R, to provide a conservative estimate of information time at each interim analysis.

CATCH: family process evaluation in a multicenter trial

The Child and Adolescent Trial for Cardiovascular Health (CATCH) is an elementary school cardiovascular health education field trial in progress in San Diego, California, New Orleans, Louisiana, Minneapolis, Minnesota, and Austin, Texas. Because a significant part of a child's health behaviors are shaped within the home, CATCH is evaluating whether the effects of the school-based program are enhanced by the inclusion of a home-based program. A 7 x 7 x 10 randomized design with 7 school-only and 7 school-plus-family intervention schools, along with 10 control schools is implemented at each site. The CATCH family intervention is implemented during Grades 3 through 5 and consists of home-based curricula and Family Fun Nights focusing on healthier eating and increased physical activity during Grades 3 and 4, along with a smoking prevention curriculum in Grade 5. CATCH is examining the effectiveness of family (household) involvement through changes in students' dietary intake of fat and sodium. This paper describes the process evaluation methods used to document the extent of participation in the family program. Data reported for the third-grade Family Fun Nights held in the 28 family schools across all sites reflected an average student participation rate of 67%. The average family member to student ratio was approximately 2:1. Participation by all third-grade teachers and the majority of physical education specialists was observed.

Testing for differences in changes in the presence of censoring: parametric and non-parametric methods

Some commonly used parametric and non-parametric methods for analysing repeated measures with incomplete observations are briefly reviewed. The performances of these methods in the presence of completely random, as well as informative censoring are compared in simulated experiments generated under the linear random effects model with parameter values derived from realistic examples. The effects of some moderate model deviations are also compared. The results indicate that in the presence of informative censoring, the usual parametric and nonparametric methods derived under the assumption of random censoring could either suffer severe loss of power or provide false positive results. The conditional linear model for informative censoring when used in conjunction with the bootstrap variance estimation procedure performed well under both random and informative censoring mechanisms. The non-parametric procedure obtained by ranking the individual summary statistics, although not as efficient as the conditional linear model with robust variance, also performed relatively well in most situations. Therefore, in situations in which informative censoring is likely to occur it is important to select the proper method of analysis to test for the informativeness of censoring and to account for its effects.

Studying the relationship between change and initial value in longitudinal studies

Blomqvist's problem of studying the relationship between change and initial value in a linear growth curve setting is reformulated from a random effects model perspective. First, a maximum likelihood estimate of the between-individual covariance matrix for a simple linear regression model with stochastic parameters is obtained via an EM algorithm as discussed by Laird and Ware. Second, the regression coefficient of the individual-specific slopes on the individual-specific intercepts is estimated as a ratio of elements of the between-individual covariance matrix as discussed by Zucker et al. Then a Fieller's type confidence interval for this ratio is proposed. Discussion is facilitated by recognizing the Laird-Ware model as a special case of a more general model discussed by Hocking.

Production and characterization of antibodies against C-terminal peptide of protein F1: a novel phosphorylation at serine 209 of the peptide by protein kinase C

Protein F1 (GAP-43, B-50, neuromodulin, P-57), a neural tissue-specific phosphoprotein enriched in the growth cones of elongating neurites, is suggested to be involved in synaptic plasticity, neuronal development, and neurotransmitter release. In this study, a 21 amino acid polypeptide (AKPKES*ARQDEGKEDPEADQE) that corresponds to the C-terminus sequence of protein F1 (from position 204-224) was synthesized and used to produce anti-protein F1 antibodies. Immunoblot analysis has demonstrated that the prepared antibodies recognized intact protein F1. Protein F1 and the synthesized F1 peptide were phosphorylated in vitro by PKC. Furthermore, phosphorylated protein F1 was immunoprecipitated by anti-F1 peptide antibodies demonstrating that these antibodies recognized both native, non-phosphorylated and phosphorylated protein. The anti-protein F1 antibodies also stained the plasma membranes of cell bodies and neuritis of mouse neuronal cultures obtained from 14-day old spinal embryonic tissue. By contrast, no glial cells were stained. These data suggest that serine 209 at the C-terminus of protein F1 may be a substrate for PKC phosphorylation in vivo. In addition, antibodies raised against F1 peptide revealed protein F1 immunoreactivity that outlined all neurites of cultured mouse spinal neurons.

Pharmacokinetics of recombinant secretory leukoprotease inhibitor aerosolized to normals and individuals with cystic fibrosis

Recombinant secretory leukoprotease inhibitor (rSLPI), a recombinant form of a natural airway inhibitor of neutrophil elastase (NE), is a potential therapeutic agent for cystic fibrosis (CF), a condition characterized by airway derangement mediated in part by the large burden of NE on the CF respiratory epithelial surface. After in vitro studies that demonstrated that aerosolized rSLPI retains its form and function, rSLPI was administered via aerosol to normal individuals and individuals with CF to determine the pharmacokinetics of in vivo rSLPI augmentation of the anti-NE defenses of the respiratory epithelial surface. After rSLPI aerosolization to normal individuals (100 mg single dose or 100 mg twice daily for 1 wk) there was a marked increase in SLPI levels and anti-NE capacity in airway epithelial lining fluid (ELF) at 1 h, diminishing gradually over 4 to 12 h. Interestingly, the ELF SLPI levels and anti-NE capacity achieved 12 h after 1 wk of rSLPI aerosols were no different than those 12 h after a single dose of rSLPI, suggesting that rSLPI does not accumulate on the respiratory epithelial surface after aerosolization. The ability of rSLPI to suppress NE in vivo was evaluated by aerosolization of rSLPI to individuals with CF, first as an escalating dose to assess safety, and then at doses of 100 mg twice daily for 1 wk or 50 mg twice daily for 2 wk.(ABSTRACT TRUNCATED AT 250 WORDS)

Alpha-fetoprotein reaction to Pisum sativum agglutinin in differentiation of benign liver diseases from hepatocellular carcinoma

Alpha-fetoprotein reactive to Pisum sativum agglutinin levels (AFP-R-PSA) was measured in sera from 124 patients with hepatocellular carcinoma (HCC) and 54 patients with benign liver diseases (BLD). The level of AFP-R-PSA in the HCC group (42% +/- 22%) was significantly higher than that in the BLD group (10% +/- 8%). When an AFP-R-PSA level above 25% was used as a value highly suggestive of HCC, the sensitivity of the test was 82%, the specificity was 96%, the accuracy was 86%, and the positive prediction value was 98%. The positive rates of AFP-R-PSA in HCC patients with a serum AFP level below 100 micrograms/L and with a serum AFP level below 400 micrograms/L were 78% and 84%, respectively. Corresponding value was 74% for 31 patients with a tumor size less than 5cm. If AFP was combined with AFP-R-PSA, the detection rate of small HCC in this study would be increased from 32% to 87%. These data indicate that measurement of AFP-R-PSA is useful for the differentiation of BLD and for the early diagnosis of HCC.

Rehepatectomy of primary liver cancer

From January 1960 to July 1991, 72 patients underwent reoperation for recurrence of liver cancer. Hepatectomy was performed twice in 59 cases, three and four times each in nine and three cases. The 1, 3, and 5-year survival rates after the first operation were 98.6%, 69.9%, and 49.5%, respectively, while after the second operation these rates were 90.8%, 53.5%, and 36.1%, respectively. The 1,2, and 3-year survival rates after the third operation were 100%, 85.6%, and 36.7%, respectively. The preliminary results of rehepatectomy are thus encouraging. The indications for reintervention, types of operation, prophylactic measures against tumor recurrence and metastases, and evaluation of rehepatectomy are discussed.

Primary hepatocellular carcinoma in women of mainland China. A clinicopathologic analysis of 104 patients

The clinicopathologic characteristics of 104 hepatectomy samples from female patients with primary hepatocellular carcinoma (PHC) were compared with similar samples from 900 male patients with primary hepatocellular carcinoma; results of this comparison were studied. The male-to-female ratio was 8.7:1. The mean age of female patients with PHC was 46.2 years, which was approximately 3 years younger (49.1 years) than that of male patients with PHC. The frequency of associated liver cirrhosis (LC) was 49% in women with PHC and 68.2% in men with PHC (P < 0.01). The mean age of the female patients without LC was 43.2 years, more than 4 years younger (47.9 years) than that of the male patients. The mean ages of female and male patients with LC were 49.1 years and 49.8 years, 6 and 2 years older than that of their corresponding groups without LC, respectively. The positive rates of serum hepatitis B surface antigen (HBsAg) were 70.8% in the men and 59.7% in the women. The 5-year postoperative survival rates were 50% in the women and 25.7% in the men (P < 0.01). It is suggested that the development of PHC in women appears at a younger age than that of PHC in men in China and usually is associated with a lower frequency of LC and a more satisfactory postoperative prognosis.

Primary hepatocellular carcinoma in women of mainland China. A clinicopathologic analysis of 104 patients

The clinicopathologic characteristics of 104 hepatectomy samples from female patients with primary hepatocellular carcinoma (PHC) were compared with similar samples from 900 male patients with primary hepatocellular carcinoma; results of this comparison were studied. The male-to-female ratio was 8.7:1. The mean age of female patients with PHC was 46.2 years, which was approximately 3 years younger (49.1 years) than that of male patients with PHC. The frequency of associated liver cirrhosis (LC) was 49% in women with PHC and 68.2% in men with PHC (P < 0.01). The mean age of the female patients without LC was 43.2 years, more than 4 years younger (47.9 years) than that of the male patients. The mean ages of female and male patients with LC were 49.1 years and 49.8 years, 6 and 2 years older than that of their corresponding groups without LC, respectively. The positive rates of serum hepatitis B surface antigen (HBsAg) were 70.8% in the men and 59.7% in the women. The 5-year postoperative survival rates were 50% in the women and 25.7% in the men (P < 0.01). It is suggested that the development of PHC in women appears at a younger age than that of PHC in men in China and usually is associated with a lower frequency of LC and a more satisfactory postoperative prognosis.

Evidence for unusual stability of ADP-ribosyl linkage to membrane proteins of a murine leukemic cell line

A set of membrane proteins from murine myelomonocytic leukemia cell line WEHI-3BD+ was found to be ADP-ribosylated. Both this ADP-ribosylation reaction and granulocytic differentiation in response to recombinant G-CSF were inhibited approximately 50% by 2 mM benzamide, suggesting a correlation between these two processes. The stability of the ADP-ribosyl linkage was examined under a series of chemical release conditions and was found to resemble none of the known ADP-ribosyl-amino acid linkages. This chemical modification may represent a new class of mono(ADP-ribosyl) modifications of proteins.

Sequential monitoring for comparison of changes in a response variable in clinical studies

The spending function approach proposed by Lan and DeMets (1983, Biometrika 70, 659-663) for sequential monitoring of clinical trials is applied to situations where comparison of changes in a continuous response variable between two groups is the primary concern. Death, loss to follow-up, and missed visits could cause follow-up measurements to be right-censored or missing for some participants. Furthermore, the probability of being censored may be dependent on the parameter value of the response variable (informative censoring). We propose to compare treatment effects by comparing areas under the expected response change curves between the two groups. When the response curves are linear as a function of time in both groups, this comparison is equivalent to comparing the rates of change in the response variable. Covariances of the sequential test statistics are derived. Conditions for having independent increments are presented. For studies designed to evaluate long-term treatment effects, spending functions obtained by shifting the usual spending functions (Kim and DeMets, 1987, Biometrika 74, 149-154) to the right and then rescaling to the remaining interval are also proposed. Such a shifted spending function is applied to the monitoring plan for the Lung Health Study (Anthonisen, 1989, American Review of Respiratory Diseases 140, 871-872).

Induction of human monocyte cell line U937 differentiation and CSF-1 production by phorbol ester

The monoblast-like human histiocytic lymphoma cell line U937 can be induced by phorbol 12-myristate 13-acetate (PMA) at concentrations of 8-16 ng/ml to undergo differentiation. The induced cells show growth inhibition, morphological changes to monocyte-macrophage-like cells, and increases in nitroblue tetrazolium (NBT) and nonspecific esterase activities. The expression of surface markers MO1 and MO2 for macrophages is also elevated. The induced differentiation of U937 cells is accompanied by the appearance of colony-stimulating activity in the culture medium as assayed on mouse bone marrow cells. Gel filtration chromatography of the conditioned media shows a peak of colony-stimulating factor (CSF) activity with an apparent molecular weight of approximately 100 kd. Morphological analysis of the colonies reveals a predominant monocyte-macrophage population. This CSF activity can be neutralized by anti-human colony-stimulating factor 1 (CSF-1) antibody, and Western blot analysis shows a CSF-1 band. All these results strongly indicate that CSF produced by induced U937 cells is CSF-1. Northern blot analysis of RNA isolated from U937 cells demonstrated that CSF-1 gene expression started after PMA induction for 3 h and declined after 18 h. Protooncogenes c-fos and c-jun were expressed after half an hour of incubation with PMA.