Embryonic stem cell lines from MRL mice allow genetic modification in a murine model of autoimmune disease

The MRL/MpJ-Fas(lpr) (MRL-lpr/lpr) mouse spontaneously develops a generalized autoimmune disease with features similar to those of systemic lupus erythematosus. This mouse strain provides a valuable system for identifying and characterizing the multiple genetic factors that influence the pathogenesis of autoimmune diseases. One of the most powerful means of examining the role of a specific gene product in vivo is by inactivating the gene in mouse embryonic stem (ES) cells by homologous recombination and using these cells to derive mouse lines carrying the inactivated gene. The successful application of this approach, however, requires an ES cell line that will remain stable in culture during the processes of genetic manipulation and selection. To date, ES cell lines that meet this criterion have been derived from only a few mouse strains. Here we describe the production and characterization of stable ES cell lines from the MRL mouse strain. Approximately 7% of the blastocysts derived from the MRL/MpJ+ (MRL-+/+) strain gave rise to ES cell lines, and both of the male MRL-+/+ ES cell lines tested were shown to be germline competent. We show that the MRL-+/+ ES cell lines undergo gene targeting by homologous recombination at high frequency by inactivating the gene encoding the EP2 prostaglandin receptor. These Ep2-targeted MRL ES cell lines were used to generate MRL mouse lines heterozygous for the disrupted Ep2 gene, thus demonstrating the feasibility of using a genetic approach to dissect the pathobiology of the autoimmune disease in the MRL mouse.

Concordance of genetic alterations in poorly differentiated colorectal neuroendocrine carcinomas and associated adenocarcinomas

BACKGROUND

The histopathologic spectrum of colorectal neuroendocrine tumors ranges from benign to highly malignant. In this spectrum, poorly differentiated neuroendocrine carcinoma (PDNC) is the most aggressive type, characterized by early dissemination and a rapidly fatal course. Since it is unclear whether PDNC originates from neoplastic transformation of preexisting neuroectodermal cells, pluripotent epithelial stem cells, or adenocarcinoma precursor cells, we investigated the histogenesis of this type of cancer by performing genetic analyses on a series of colorectal tumors.

METHODS

Archived histologic sections of colorectal PDNC from nine patients were analyzed; gastrointestinal carcinoid tumor specimens from four patients were used as controls. The specimens were deparaffinized, microdissected, and analyzed genetically. After DNA extraction, polymerase chain reaction amplification was performed to investigate alteration (i.e., loss of heterozygosity [LOH]) of the APC (adenomatous polyposis coli), DCC (deleted in colorectal carcinoma), and p53 (also known as TP53) genes.

RESULTS

LOH of the APC, DCC, or p53 genes was observed in six of eight informative PDNC tumors; no LOH was detected in the carcinoid control specimens. Four of five informative PDNC tumors had associated adenocarcinoma; LOH of the APC and p53 genes in these tumors involved the same allele in both tissue components. Four of the five tumors with associated adenocarcinoma showed LOH of the DCC gene; in three of these four tumors, the PDNC and adenomatous components showed LOH of the same allele.

CONCLUSIONS

PDNC and associated adenocarcinoma appear to be derived from the same cell of origin, which is most likely either a pluripotent epithelial stem cell or an adenocarcinoma precursor cell.

Carcinogenecity of the N-acyl derivatives of N-hydroxy-trans-4-aminostilbene in CD rats

Carcinogenicities of the N-formyl (N-OH-FAS), N-acetyl (N-OH-AAS) and N-propionyl (N-OH-PAS) derivatives of N-hydroxy-trans-4-aminostilbene (N-OH-AS) were investigated in male and female CD rats. They were injected, i.p. 10 mumol/kg body weight (bwt) twice a week for 6 weeks, and they were killed at the end of 62 weeks. The N-formyl, N-acetyl and N-propionyl derivatives of N-hydroxy-4-aminobiphenyl (N-OH-ABP) were similarly injected at a dose of 100 mumol/kg bwt for comparison in female CD rats. Tumors of the liver, mammary gland and ear duct were produced in the female rats by these N-OH-AS derivatives. N-OH-AAS and N-OH-PAS were more active in the induction of mammary and ear duct tumors than N-OH-FAS. These N-OH-AS derivatives produced more tumors than did the N-OH-ABP derivatives, even at 1/10 dose of the N-OH-ABP derivatives. In male CD rats, these N-OH-AS derivatives produced peritesticular mesothelioma and tumors of the pancreas and ear duct. N-OH-PAS also produced tumors of the small intestine and lung. The acetyl and propionyl derivatives were more carcinogenic than the formyl derivative of N-OH-AS for both male and female CD rats, suggesting that cytosolic acetyltransferases may be more important than the microsomal ones in activating these carcinogens.

New developments in the use of cytokines for cancer therapy

Cytokines, the pleiotropic immune regulatory proteins, are involved in the regulation of cell growth, differentiation and functional activation. Novel cytokines have been enumerated in rapid succession and entered the clinical arena. IL-2 is well recognized for its antitumor effects and is accepted therapy for numerous malignancies. IL-l and IL-11 are important as thrombopoetic factors while IL-6 has been introduced in clinical trials as a platelet growth factor and as an antitumor agent. IL-4 has shown growth inhibitory effects against many solid tumor cell lines in vitro, but its direct effect on human tumors in vivo remains to be explored. IL-7 may be an important addition to the current strategies of adoptive immunotherapy. IL-12 plays a fundamental role in activating antitumor cellular immunity. When given with tumor associated antigens, IL-12 has proven effective against many forms of metastatic solid tumors. Immunotoxins appear to be promising, though the antigenicity of the molecule and antibody development aspects remain to be resolved. The current review will focus on the clinical use of novel cytokines for the treatment of cancer.

Synthetic-peptide-based enzyme-linked immunosorbent assay for screening human serum or plasma for antibodies to human immunodeficiency virus type 1 and type 2

A synthetic-peptide-based enzyme-linked immunosorbent assay (EIA) capable of screening for antibodies to both human immunodeficiency virus type 1 (HIV-1) and HIV-2 has been developed for use in blood banks and diagnostic laboratories. Microtiter wells are coated with two synthetic peptides, one corresponding to the highly conserved envelope region of HIV-1 and another corresponding to the conserved envelope region of HIV-2. Overall, sensitivity was 100% in 303 individuals diagnosed with AIDS and 96 individuals diagnosed with AIDS-related complex, 14.8% in a study of 500 high-risk group members, 99.9% in 600 EIA repeatedly reactive (RR)-HIV-1 Western blot (WB)-positive repository specimens, and 100% for 222 geographically diverse HIV-1 specimens and 216 confirmed HIV-2-positive specimens evaluated. The specificity was determined to be 99.72% for a total of 13,004 serum and plasma samples from random volunteer donors evaluated across five blood banks. Forty donors who were found to be EIA RR-WB indeterminate but nonreactive on the United Biomedical, Inc., test (UBI HIV 1/2 EIA) were prospectively followed as an additional measure of specificity. None of the 40 low-risk cases evolved into a positive WB pattern at follow-up. The sensitivity and specificity of this new assay are comparable to those of other Food and Drug Administration-licensed HIV-1 and HIV-1-HIV-2 assays that are currently available in the United States. The UBI HIV 1/2 EIA affords laboratories another choice in the detection of antibodies for HIV-1 and HIV-2 with a test based on an alternative antigen format.

Interleukin-13 receptors on human prostate carcinoma cell lines represent a novel target for a chimeric protein composed of IL-13 and a mutated form of Pseudomonas exotoxin

We have discovered a new cell surface protein in the form of interleukin-13 receptor on several solid tumor cells, including human renal cell carcinoma cells (Obiri et al., 1995; Debinski et al., 1995). This study reports that human prostate cancer cell lines also express high affinity IL-13 receptors (Kd = 159 pM). These receptors are functional because IL-13 surprisingly increased proliferation of all three prostate cancer cell lines studied as determined by thymidine uptake and clonogenic assays. IL-13 receptors on prostate cancer cell lines were targeted using a chimeric protein composed of IL-13 and a mutated form of Pseudomonas exotoxin (PE38QQR). This molecule, termed IL13-PE38QQR, has been found cytotoxic to all three prostate cancer cell lines as determined by the inhibition of protein synthesis. The IC50 ranged between 1 nmol/l, to 15 nmol/l. These data were confirmed by clonogenic assays in which IL13-PE38QQR almost completely inhibited colony formation at 10 nmol/l. IL13-PE38QQR was not cytotoxic to cells that express little or no IL-13R. Heat inactivated IL13-PE38QQR was not cytotoxic to prostate cancer cells indicating specificity. IL13-PE38QQR was also cytotoxic to colonies when they were allowed to form first for several days before the addition of toxins. Our data suggest that additional studies should be performed to target IL-13 receptor bearing prostate cancer.

Increased susceptibility of RAG-2 SCID mice to dissemination of endodontic infections

Specific immunity has been implicated in the pathogenesis of periapical lesions, although the extent to which these mechanisms are actually involved in either protection or destruction of the pulp-periapex complex is yet to be established. To investigate this question we compared periapical-lesion pathogenesis in RAG-2 severe combined immunodeficient (SCID) mice with immunocompetent control mice following surgical pulp exposure. In order to equalize the bacterial challenge, an infection protocol using Prevotella intermedia, Fusobacterium nucleatum, Peptostreptococcus micros, and Streptococcus intermedius was devised. The results demonstrated that after infection, the proportion of the root canal flora represented by the four pathogens was almost identical in both groups (39.9 and 42.2% for RAG-2 and immunocompetent control mice, respectively). The effects of abrogation of T- and B-cell mechanisms on periapical pathogenesis were then assessed. Approximately one-third of the RAG-2 mice developed endodontic abscesses, while no immunocompetent controls had abscesses, results which indicated regional dissemination of the infection. A similar incidence of abscesses was found in two additional experiments. Abscessed RAG-2 teeth had significantly larger periapical lesions than did nonabscessed RAG-2 teeth (P < or = 0.05) and exposed immunocompetent controls (P < or = 0.01), whereas nonabscessed RAG-2 teeth were not significantly different from those of exposed immunocompetent controls in periapical-lesion size. We conclude that B- and T-cell-mediated immunity protects the host from the dissemination of endodontic infections and that RAG-2 mice are more susceptible to infection-induced pulp-periapex destruction.

The cross-cultural applicability of Orem's conceptual framework

This study examined the applicability of the Orem's Theory of Self-Care with Chinese clients. The central concepts included the universal self-care behaviors (USC), health-deviation self-care behaviors (HDSC), health, and the basic conditioning factors of adults with Type II diabetes mellitus. Basic conditioning factors (BCF) were internal or external factors that affected an individual's ability to engage in self-care bahaviors (Orem, 1991). This study used a descriptive correlation design. Orem's theory of self-care guided the selection of the variables and the hypothesized outcomes. Data were collected through phone interviews of 100 Chinese at Taiwan. The average age was 57.88 (SD = 12.41). A total of 51 items on questionnaires was used to measure self-care behaviors and health. An investigator developed a questionnaire assessing sociodemographic characteristics. Sixty-six percent of respondents perceived they lived with someone who helped too much and hindered their own diabetes-related self-care. A significant correlation was found between educational level and diabetes-related self-care behaviors. A significant correlation was also found between the educational level and the universal self-care behaviors. There were significant correlations among the universal self-care behaviors and diabetes-related self-care; between the universal self-care behaviors and the perception of health; between the diabetes-related self-care behaviors and the perception of health. The findings implicated cross-cultural applicability of Orem's conceptual framework.

Adaptive control of arterial blood pressure with a learning controller based on multilayer neural networks

We discuss a two-model multilayer neural network controller for adaptive control of mean arterial blood pressure (MABP) using sodium nitroprusside. A model with an autoregressive moving average (ARMA), representing the dynamics of the system, and a modified back-propagation training algorithm are used to design the control system to meet specified objectives of design (settling time and undershoot/overshoot) and clinical constraints. The controller is associated with a weighting-determinant unit (WDU) to determine and update the output weighting factor of the parallel two-model neural network for adequate control action and a control-signal modification unit (CMU) to comply with clinical constraints and to suppress the effect of adverse noise and to improve the WDU performance. Extensive computer simulations indicate satisfactory performance and robustness of the proposed controller in the presence of much noise, over the full range of plant parameters, uncertainties, and large variations of parameters.

Comparative pathology of benign prostatic hyperplasia and prostate cancer

Basic studies on the pathogenesis of prostate disease including hypertrophy and cancer have been difficult due to the lack of suitable animal models. Much effort has been directed to the development of appropriate animal models, and yet many obstacles still remain. Rodents do not develop spontaneous hypertrophy of the prostate, in fact the prostate atrophies with advancing age. Guinea pigs appear to be a good model to study the effect of hormones on the prostate gland. Microinvasive prostatic adenocarcinoma occurs spontaneously in various species of rodents, and can be induced by radiation, hormones and chemical carcinogens. The man and dog appear to be the only mammals which suffer naturally from the pathological processes of the prostate gland associated with aging. We review the currently available models for the study of benign, and malignant prostate disease and assess the strengths and weaknesses each for preclinical investigations.

A model for osseous metastasis of human breast cancer established by intrafemur injection of the MDA-MB-435 cells in nude mice

BACKGROUND

A nude mouse model was developed and studied for temporal pathogenesis of bony metastasis of human breast cancer.

MATERIALS AND METHODS

Human breast cancer cells, MDA-MB-435, were injected into the medulla of left femurs of 10 Beige nude mice, whereas their right femurs were similarly injected with phosphate buffered saline as a control. The mice were killed at 1 week-intervals for up to 5 weeks.

RESULTS

Tumors appeared in all the animals 3 weeks after the injection: they began to appear in the medulla at 2 weeks, and invasion of the tumor into the cortex and surrounding tissues of the bone appeared at 4 weeks. Both osteolytic and osteoblastic activation frequently observed in the affected bone of breast cancer patients were present.

CONCLUSION

This model produces a high incidence of bony metastasis and may be appropriate for the study of osseous metastasis of this human disease.

Identification of a second endogenous Porphyromonas gingivalis insertion element

In this study a second endogenous Porphyromonas gingivalis insertion element (IS element) that is capable of transposition within P. gingivalis was identified. Nucleotide sequence analysis of the Tn4351 insertion site in a P. gingivalis Tn4351-generated transconjugant showed that a complete copy of the previously unidentified IS element, designated PGIS2, had inserted into IS4351R in Tn4351. PGIS2 is 1,207 bp in length with 19-bp imperfect terminal inverted repeats, and insertion resulted in a duplicated 10-bp target sequence. Results of Southern hybridization of chromosomal DNA isolated from several P. gingivalis strains with a PGIS2-specific probe demonstrated that the number of copies of PGIS2 per genome varies among different P. gingivalis strains. Computer analysis of the putative polypeptide encoded by PGIS2 revealed strong homologies to the products encoded by IS1358 from Vibrio cholerae, ISAS1 from Aeromonas salmonicida, and H-rpt in Escherichia coli K-12.

Reflux esophagitis after proximal subtotal gastrectomy

BACKGROUND

Carcinoma of the cardia of stomach or carcinoma of the esophagocardiac (EC) junction has a poor prognosis. Proximal subtotal gastrectomy is often performed for a smaller tumor. It achieves a prognosis similar to that of total gastrectomy and prevents pernicious anemia. A better functional result was expected than that total gastrectomy did from us, but the clinical observation was surprising. Most patients had symptoms of reflux esophagitis after surgery. All of these patients were reevaluated.

METHODS

From November, 1990 to March, 1996, there were 27 patients who received proximal subtotal gastrectomy at this hospital. Twenty of these were involved in this study. Floppy Nissen's fundoplication was performed during operation as a anti-reflux procedure. Continuous 24-h pH monitoring, esophageal manometry, and endoscopic examination were performed for study.

RESULTS

Most of the patients had symptoms of gastroesophageal reflux. 80% (16/20) of the patients were found to have reflux esophagitis under endoscopy. The patients had higher pH scores (mean 85.8 +/- 45.6) than normal (< 17.5), lower pressure of LES (8.03 +/- 7.01 mmHg), shorter total lengths (mean 1.60 +/- 0.56 cm) and intraabdominal lengths (mean 1.29 +/- 0.30 cm) of new lower esophageal sphincters.

CONCLUSIONS

Clearly there was failure to prevent reflux esophagitis through floppy Nissen's fundoplication. Severe gastroesophageal reflux did appear after proximal gastric resection. A gastric remnant with safe cut-margin is often too short to perform complete wrapping. Proximal subtotal gastrectomy is not recommended for early cancer of the cardia of the stomach.

Homozygosity and linkage-disequilibrium mapping of the urofacial (Ochoa) syndrome gene to a 1-cM interval on chromosome 10q23-q24

The urofacial (Ochoa) syndrome (UFS) is a rare autosomal recessive disease characterized by congenital obstructive uropathy and abnormal facial expression. The patients present with enuresis, urinary-tract infection, hydronephrosis, and voiding dysfunctions as a result of neurogenic bladders. To map the UFS gene, a genome screen using a combination of homozygosity-mapping and DNA-pooling strategies was performed in 20 selected patients, one patient pool, and three control pools (unaffected relatives). After analyses of 36 randomly chosen markers, D10S677 was identified as being linked to and associated with UFS, as suggested by a significant excess of homozygosity in patients compared with that in unaffected relatives (P < 10(-6)), as well as by the allelic-frequency differences between the patient pool and control pools. Ten additional markers flanking D10S677 and covering a 22-cM region then were analyzed to fine-map the UFS gene by use of haplotype (linkage disequilibrium) analysis. All 31 patients were found to be homozygous for two closely linked markers (D10S1726 and D10S198) located approximately 5 cM telomeric to D10S677, whereas only 12% of the unaffected relatives were homozygous for both markers (P < 10(-19)). Several patients are heterozygous at two markers immediately flanking D10S1726/D10S198, one on the centromeric side (D10S1433) and the other on the telomeric side (D10S603). These recombinational events place the UFS gene near D10S1726/D10S198 and within a 1-cM interval defined by D10S1433 and D10S603 on chromosome 10q23-q24.

International clinical trials of HIV vaccines: II. phase I trial of an HIV-1 synthetic peptide vaccine evaluating an accelerated immunization schedule in Yunnan, China

A Phase 1, double-blind, placebo controlled trial was conducted in Longchuan County, China, to evaluate the safety and immunogenicity of a prototype HIV-1 synthetic peptide vaccine in a target population at risk for HIV infection, and to establish the infrastructure for future large-scale HIV vaccine efficacy trials. Subjects were randomly assigned to receive 100 microg or 500 microg of vaccine or alum placebo, and were given three injections at an accelerated 0, 1, and 2 month schedule. The vaccine was well tolerated with no significant local or systemic reactions observed in any subjects. Fifty-five percent (100 microg dose) and 64% (500 microg dose) of subjects who received the vaccine produced binding antibody to the immunogen as determined by ELISA. However, HIV-1 (MN) neutralizing antibody was detected in only 23% (3/13) of subjects with detectable HIV-1 specific binding antibody. It was concluded that this prototype HIV-1 synthetic peptide vaccine was well tolerated, safe and immunogenic, and that a 0, 1, 2 month schedule was not as effective in stimulating HIV-1 specific neutralizing antibodies compared with previous trials utilizing a 0, 1, 6 month schedule. Finally, this trial demonstrated that well-designed HIV vaccine trials can be performed at this clinical trials site in Yunnan, China, and that this site should be considered for conducting larger safety, immunogenicity and efficacy trials of candidate HIV vaccines.

Biological growth on a surface

A new biological growth model is introduced. After random selection of possible growth sites, cells are added in an allowable random direction. Unlike the Eden model, the current model is grid independent and can be adapted to any curved surface. Growths of colonies of as many as 10(5) cells are simulated on planar, cylindrical, and spherical surfaces. It is found that the interior density is constant, whereas the boundary is fractal.

Role of acetyltransferases in the metabolism and carcinogenicity of aromatic amines

The genotoxicity of N-substituted aryl compounds is dependent on their conversion to reactive metabolites, frequently through the production of reactive N-acetoxyarylamines. This activation is accomplished by acetyltransferases that are widely distributed. In the rat, the production of N-acetoxyarylamines has been most clearly related to the induction of tumors in the mammary gland, but this pathway also appears to be an important factor in the production of tumors in the liver, Zymbal gland and gastrointestinal tract. Expression of rat acetyltransferases responsible for acetylation of the nitrogen and the oxygen of arylamine derivatives (i.e., acetyltransferases 1 and 2) in bacterial cells has now permitted experiments which demonstrate that these enzymes exhibit good affinities for and N-acetylation of the endogenous arylalkylamines derived from tryptophan, i.e., tryptamine, 5-hydroxytryptamine (serotonin) and 5-methoxytryptamine, the immediate metabolic precursor of melatonin. Evidence that these reactions are likely to reflect real biological potentials is bolstered by histological localization of acetyltransferase mRNAs with synthetic antisense oligodeoxynucleotide probes. The results of these studies in rat indicate that the expression of acetyltransferase in tissues of the central nervous, gastrointestinal, urinary and reproductive systems is highly regulated, as it is in other organs commonly associated with aromatic amine carcinogenicity. Similar experimental approaches have been successful with human liver, mammary gland, kidney and bladder preparations. These observations give evidence that genotoxic N-acetoxyarylamines are produced by acetyltransferases that can metabolize, and possibly modulate, the hormonal and neurotransmitter effects of endogenous arylalkylamines. These relationships may help explain the occasional induction of tumors in organs not usually considered as targets of aromatic amines, as well as raise the possibility that the production of N-oxidized endogenous substrates may represent a mechanism for tumor induction in the absence of exogenous carcinogens.

Immunogenicity and protection in small-animal models with controlled-release tetanus toxoid microparticles as a single-dose vaccine

Tetanus toxoid (TT) was encapsulated in microparticles prepared from polylactide-co-glycolide polymers by a solvent-evaporation technique. Combinations of small- and large-sized microparticles with controlled-release characteristics were used to immunize Sprague-Dawley rats, and the antibody responses were monitored for 1 year. For comparison, control groups of rats were immunized at 0, 1, and 2 months with TT adsorbed to alum. The antibody responses generated by the TT entrapped in microparticles were comparable to those generated by TT adsorbed to alum in control groups from 32 weeks onwards. Microparticles with a single entrapped antigen (TT) induced better antibody responses than microparticles with two antigens (TT and diphtheria toxoid) entrapped simultaneously. A combination vaccine consisting of TT adsorbed to alum and also entrapped in microparticles gave the best antibody responses. In an inhibition assay designed to determine the relative levels of binding of antisera to the antigens, the sera from the microparticle- and the alum-immunized animals showed comparable levels of binding. In addition, in a passive-challenge study with mice, TT adsorbed to alum and TT entrapped in microparticles provided equal levels of protection against a lethal challenge with tetanus toxin. An intradermal-challenge study was also performed with rabbits, which showed similar levels of protection in sera from alum- and microparticle-immunized animals at 4, 12, and 32 weeks after immunization.

Controlled release microparticles as a single dose hepatitis B vaccine: evaluation of immunogenicity in mice

Hepatitis B surface antigen (HBsAg) was encapsulated in microparticles prepared from polylactide-co-glycolide (PLG) and polylactide (PLA) polymers using a solvent evaporation process. The immunoreactivity of the entrapped antigen was investigated by SDS-PAGE and Western blot. The microencapsulation process was modified to obtain both small (< 10 microns) and large microparticles (10-100 < microns). 80% of the antigen was encapsulated. Various combinations of small and large microparticles with controlled release characteristics were investigated in CD1 mice. Groups of animals were immunized with 30 micrograms equivalent of HBsAg in microparticles per animals. The control group received, three injections of 10 micrograms of HBsAg on alum at 0, 1 and 6 months. Results indicated that a single injection of HBsAg in microparticles could maintain the antibody response at a level comparable to the three-injection alum schedule for at least 1 year. An in vitro inhibition assay was developed to demonstrate that antigen-antibody reactivity were comparable for the microparticle immunized mice and the alum immunized mice. A competition assay with a monoclonal antibody specific for the neutralizing epitope of HBsAg demonstrated comparable binding for the sera from the microparticle and alum immunized mice.

Light-induced fluorescence spectroscopy to differentiate benign and malignant uterine cervical lesions

In Taiwan, cervical cancer is the leading malignancy among women. For the early detection of cervical neoplasia, light-induced fluorescence spectroscopy was conducted ex vivo to assess the ability of this technique to differentiate cervical neoplastic tissue (20 samples) from normal or inflammatory cervical tissue (37 samples) at an excitation wavelength of 280 nm. The principal fluorescent peaks occurred within +/- 5 nm of 330 nm and 470 nm emission. At 330 nm emission, the spectrum of the normal or inflammatory tissue was significantly stronger than that of the neoplastic tissue after are normalization. However, at 470 nm emission, the spectrum of the normal or inflammatory tissue was significantly weaker than that of the neoplastic tissue. A diagnostic algorithm based on the ratio of relative intensities of 330 nm to 470 nm emission within the 5 +/- nm peak area of each sample was calculated and paired. The ratios showed that histologically neoplastic lesions could be distinguished from inflammatory samples using a 280-nm-excitation wavelength with a sensitivity, specificity and positive predictive value of 94%, 82% and 73%, respectively. The average ratio of malignant or dysplastic cervical samples was significantly greater than that of the inflammatory samples (p < 0.001). Our ex vivo study indicated that light-induced fluorescence spectroscopy may be useful in differentiating malignant or premalignant from normal or inflammatory cervical tissue.

Bone-resorptive cytokine gene expression in periapical lesions in the rat

Periapical bone destruction is an important pathogenic sequela of pulpal infection. Recent findings from this laboratory have demonstrated that most bone-resorbing activity in extracts of rat periapical lesions can be neutralized by an anti-interleukin (IL)-1 alpha antiserum. To further clarify pathogenic mechanisms, bone-resorptive cytokine messenger RNA (mRNA) expression was analyzed in developing rat periapical lesions. The molar teeth of 20 Sprague-Dawley rats were surgically exposed and left open to permit infection from the oral environment. Total cell RNA was isolated from periapical granuloma tissue obtained on days 3, 7, 15 and 30 after exposure. mRNA for IL-1 alpha, IL-1 beta and tumor necrosis factor alpha (TNF-alpha) was amplified by reverse transcription polymerase chain reaction, and levels were approximated by comparison to the parallel amplification of the housekeeping gene glyceraldehyde phosphate dehydrogenase. IL-1 alpha and TNF-alpha mRNA were both highly expressed beginning on day 7, increased on day 15, and declined somewhat on day 30. In contrast, IL-1 beta mRNA was expressed at much lower levels, but with similar kinetics. The kinetics of steady state IL-1 alpha and TNF-alpha mRNA levels were confirmed using the quantitative RNase protection assay, whereas IL-1 beta mRNA could not be detected by this technique. IL-1 alpha mRNA-expressing cells were identified using in situ hybridization and included infiltrating macrophages, as well as resident fibroblasts, endothelial cells and osteoclasts. These results demonstrate that the IL-1 alpha and TNF-alpha genes are highly expressed in developing periapical lesions in the rat and confirm previous studies at the protein level in this model.

Serial changes in ultrasound-guided fine needle aspiration cytology in subacute thyroiditis

OBJECTIVE

To elucidate the serial cytologic presentations of subacute thyroiditis (SAT) with ultrasound-guided fine needle aspiration (FNA).

STUDY DESIGN

Nine patients with clinically evident SAT were recruited; serial sonography and ultrasound-guided fine needle aspiration cytology were performed.

RESULTS

Sixty-one follow-up examinations were obtained in nine patients. The follow-up ranged from 1 to 5 months (mean, 3.3). Initial sonographic presentations revealed focal hypoechogenicity in three patients and multiple hypoechogenicity in six. Initial cytologic findings showed chiefly enlarged, degenerated follicular cells with prominent nucleoli, lymphocytes, colloid substance, multinucleated giant cells and neutrophils. Regression of sonographic hypoechogenicity paralleled the disappearance of acute inflammatory cells and enlarged, degenerated follicular cells and the appearance of cohesive follicles.

CONCLUSION

Improvement of SAT in sonography is fairly parallel to that in cytology even though there is a lag of improvement in the latter. Smear pattern is also related to the clinical stage of SAT. Ultrasound-guided FNA is a convenient method of obtaining sufficient and representative specimens in patients with SAT.

Specific immobilization of firefly luciferase through a biotin carboxyl carrier protein domain

Firefly luciferase (Photinus pyralis) was fused with a histidine tag and a biotin carboxyl carrier protein (BCCP) domain at its amino terminus. Highly purified recombinant luciferase was obtained by a one-step purification protocol, utilizing immobilized metal affinity chromatography. The novel BCCP-luciferase had properties, stability, and activity similar to those of native luciferase. The biotin molecule on the BCCP domain allowed specific immobilization of BCCP-luciferase on avidin-coated surfaces via the biotin-avidin interaction.

Regression calibration in failure time regression

In this paper we study a regression calibration method for failure time regression analysis when data on some covariates are missing or mismeasured. The method estimates the missing data based on the data structure estimated from a validation data set, a random subsample of the study cohort in which covariates are always observed. Ordinary Cox (1972; Journal of the Royal Statistical Society, Series B 34, 187-220) regression is then applied to estimate the regression coefficients, using the observed covariates in the validation data set and the estimated covariates in the nonvalidation data set. The method can be easily implemented. We present the asymptotic theory of the proposed estimator. Finite sample performance is examined and compared with an estimated partial likelihood estimator and other related methods via simulation studies, where the proposed method performs well even though it is technically inconsistent. Finally, we illustrate the method with a mouse leukemia data set.

International clinical trials of HIV vaccines: I. Phase I trial of an HIV-1 synthetic peptide vaccine in Bangkok, Thailand

A randomized, double blind, placebo controlled Phase I trial of a prototype human immunodeficiency virus type 1 (HIV-1) synthetic peptide vaccine was conducted in Bangkok, Thailand, to evaluate the safety and immunogenicity of the vaccine in a population of healthy adults at low risk for HIV infection, and to establish essential infrastructure for future HIV vaccine trials in Thailand. Thirty volunteers (25 males; 5 females) were recruited and randomized into 3 groups, receiving 3 intramuscular injections of either 100 micrograms vaccine (N = 12) or 500 micrograms vaccine (N = 12) or alum placebo (N = 6) on weeks 0, 4 and 25. The vaccine was well tolerated without any serious adverse effects. HIV-1 specific ELISA responses were detected in 20/24 subjects who received the vaccine, with V3 binding antibody titers ranging from 1:69 to 1:5,041. HIV-1 (MN) specific neutralizing antibody was detected in 19/20 of subjects with detectable HIV-1 specific binding antibody. Neutralization titers ranged from 1:14 to 1:1,294, which were less than titers observed in HIV-infected subjects. The results of this study indicate that the vaccine was well tolerated, and that the vaccine stimulated anti-HIV humoral immune responses in Thai subjects. The successful undertaking of this first HIV vaccine trial conducted in Thailand provided important preparatory information surrounding volunteer recruitment and motivations, and paves the way for future trials of HIV vaccines in Thailand.