Parameter Space and Potential for Biomarker Development in 25 Years of fMRI Drug Cue Reactivity: A Systematic Review

Importance

In the last 25 years, functional magnetic resonance imaging drug cue reactivity (FDCR) studies have characterized some core aspects in the neurobiology of drug addiction. However, no FDCR-derived biomarkers have been approved for treatment development or clinical adoption. Traversing this translational gap requires a systematic assessment of the FDCR literature evidence, its heterogeneity, and an evaluation of possible clinical uses of FDCR-derived biomarkers.

Objective

To summarize the state of the field of FDCR, assess their potential for biomarker development, and outline a clear process for biomarker qualification to guide future research and validation efforts.

Evidence Review

The PubMed and Medline databases were searched for every original FDCR investigation published from database inception until December 2022. Collected data covered study design, participant characteristics, FDCR task design, and whether each study provided evidence that might potentially help develop susceptibility, diagnostic, response, prognostic, predictive, or severity biomarkers for 1 or more addictive disorders.

Findings

There were 415 FDCR studies published between 1998 and 2022. Most focused on nicotine (122 [29.6%]), alcohol (120 [29.2%]), or cocaine (46 [11.1%]), and most used visual cues (354 [85.3%]). Together, these studies recruited 19 311 participants, including 13 812 individuals with past or current substance use disorders. Most studies could potentially support biomarker development, including diagnostic (143 [32.7%]), treatment response (141 [32.3%]), severity (84 [19.2%]), prognostic (30 [6.9%]), predictive (25 [5.7%]), monitoring (12 [2.7%]), and susceptibility (2 [0.5%]) biomarkers. A total of 155 interventional studies used FDCR, mostly to investigate pharmacological (67 [43.2%]) or cognitive/behavioral (51 [32.9%]) interventions; 141 studies used FDCR as a response measure, of which 125 (88.7%) reported significant interventional FDCR alterations; and 25 studies used FDCR as an intervention outcome predictor, with 24 (96%) finding significant associations between FDCR markers and treatment outcomes.

Conclusions and Relevance

Based on this systematic review and the proposed biomarker development framework, there is a pathway for the development and regulatory qualification of FDCR-based biomarkers of addiction and recovery. Further validation could support the use of FDCR-derived measures, potentially accelerating treatment development and improving diagnostic, prognostic, and predictive clinical judgments.

Effects of Preoperative Use of Povidone-Iodine-Impregnated Dressing on Postoperative Rate of Surgical Site Infection in Patients Undergoing Posterolateral Lumbar Spinal Fusion Surgery: A Randomized, Nonblinded, Active-Controlled Trial

BACKGROUND AND OBJECTIVES

No study has evaluated the efficacy of using preoperative antiseptic dressings in reducing the rate of surgical site infection (SSI) in spine surgery thus far. To investigate the efficacy of the use of preoperative povidone-iodine-impregnated antiseptic dressings in patients undergoing instrumented posterolateral lumbar spinal fusion.

METHODS

This was a randomized, nonblinded, active-controlled, parallel-group clinical trial. Patients were randomly assigned to the 2 study groups, including treatment and control. Patients in the treatment group received povidone-iodine-impregnated antiseptic dressing applied to the anticipated incision site 12 hours before the operation. The control group merely received the standard perioperative care with no additional intervention or placebo. Patients were followed up for 90 days, and SSIs were recorded.

RESULTS

A total of 200 patients were included in this study (100 in each arm). Three cases of SSI were observed in the treatment group compared with 12 in the control one. A significant reduction in the postoperative rate of SSI was observed in the treatment group compared with the control one (P = .029). In addition to study intervention (P = .029), body mass index (P = .005), smoking status (P = .005), duration of the procedure (P = .003), American Society of Anesthesiologists class (P = .002), and diabetes mellitus (P < .001) were significantly associated with the postoperative rate of SSI.

CONCLUSION

To the best of our knowledge, this study for the first time showed that preoperative use of antiseptic dressings is significantly effective in reducing the rate of SSI in instrumented posterior lumbar spinal fusion surgery. Future studies are warranted to evaluate the efficacy of different preparations or the effectiveness of the present one in patients undergoing spine procedures with other surgical characteristics.

Age and gender differences of basic electrocardiographic values and abnormalities in the general adult population; Tehran Cohort Study

BACKGROUND

Although several studies are available regarding baseline Electrocardiographic (ECG) parameters and major and minor ECG abnormalities, there is considerable controversy regarding their age and gender differences in the literature.

METHODS

Data from 7630 adults aged ≥ 35 from the Tehran Cohort Study registered between March 2016 and March 2019 were collected. Basic ECG parameters values and abnormalities related to arrhythmia, defined according to the American Heart Association definitions, were analyzed and compared between genders and four distinct age groups. The odds ratio of having any major ECG abnormality between men and women, stratified by age, was calculated.

RESULTS

The average age was 53.6 (± 12.66), and women made up 54.2% (n = 4132) of subjects. The average heart rate (HR) was higher among women(p < 0.0001), while the average values of QRS duration, P wave duration, and RR intervals were higher among men(p < 0.0001). Major ECG abnormalities were observed in 2.9% of the study population (right bundle branch block, left bundle branch block, and Atrial Fibrillation were the most common) and were more prevalent among men compared to women but without statistical significance (3.1% vs. 2.7% p = 0.188). Moreover, minor abnormalities were observed in 25.9% of the study population and again were more prevalent among men (36.4% vs. 17% p < 0.001). The prevalence of major ECG abnormalities was significantly higher in participants older than 65.

CONCLUSION

Major and minor ECG abnormalities were roughly more prevalent in male subjects. In both genders, the odds of having major ECG abnormalities surge with an increase in age.

Association between Nontraditional Risk Factors and Calculated 10-Year Risk of Atherosclerotic Cardiovascular Disease in a Large General Population: Based on the Pars Cohort Study

Background

While the traditional risk factors of atherosclerotic cardiovascular disease (ASCVD) have been well-established, the evolving role of nontraditional risk factors is not apparent. This study aimed to evaluate the association between nontraditional risk factors and the calculated 10-year ASCVD risk in a general population.

Methods

This cross-sectional study was conducted using the Pars Cohort Study data. All inhabitants of the Valashahr district in southern Iran, aged 40-75 years, were invited (2012-2014). Patients with a history of cardiovascular disease (CVD) were excluded. The demographic and lifestyle data were collected using a validated questionnaire. Multinomial logistic regression analysis was used to evaluate the association between the calculated 10-year ASCVD risk and the nontraditional risk factors of CVD, including marital status, ethnicity, educational level, tobacco and opiate consumption, physical inactivity, and psychiatric disorders.

Results

Of 9264 participants (mean age =52.2±9.0 y; 45.8% male), 7152 patients met the inclusion criteria. In total, 20.2%, 7.6%, 36.3%, 56.4%, and 46.2% of the population were cigarette smokers, opiate consumers, tobacco consumers, ethnically Fars, and illiterate, respectively. The prevalence rates of low, borderline, and intermediate-to-high 10-year ASCVD risks were 74.3%, 9.8%, and 16.2%, respectively. In multinomial regression, anxiety (adjusted odds ratio [aOR], 0.58; P<0.001) was significantly associated with a lower ASCVD risk, whereas opiate consumption (aOR, 2.94; P<0.001) and illiteracy (aOR, 2.48; P<0.001) were significantly associated with a higher ASCVD risk.

Conclusion

Nontraditional risk factors are associated with the 10-year ASCVD risk and, thus, might be considered besides traditional ones for ASCVD in preventive medicine and health policies.

Comparison of conventional scoring systems to machine learning models for the prediction of major adverse cardiovascular events in patients undergoing coronary computed tomography angiography

BACKGROUND

The study aims to compare the prognostic performance of conventional scoring systems to a machine learning (ML) model on coronary computed tomography angiography (CCTA) to discriminate between the patients with and without major adverse cardiovascular events (MACEs) and to find the most important contributing factor of MACE.

MATERIALS AND METHODS

From November to December 2019, 500 of 1586 CCTA scans were included and analyzed, then six conventional scores were calculated for each participant, and seven ML models were designed. Our study endpoints were all-cause mortality, non-fatal myocardial infarction, late coronary revascularization, and hospitalization for unstable angina or heart failure. Score performance was assessed by area under the curve (AUC) analysis.

RESULTS

Of 500 patients (mean age: 60 ± 10; 53.8% male subjects) referred for CCTA, 416 patients have met inclusion criteria, 46 patients with early (<90 days) cardiac evaluation (due to the inability to clarify the reason for the assessment, deterioration of the symptoms vs. the CCTA result), and 38 patients because of missed follow-up were not enrolled in the final analysis. Forty-six patients (11.0%) developed MACE within 20.5 ± 7.9 months of follow-up. Compared to conventional scores, ML models showed better performance, except only one model which is eXtreme Gradient Boosting had lower performance than conventional scoring systems (AUC:0.824, 95% confidence interval (CI): 0.701-0.947). Between ML models, random forest, ensemble with generalized linear, and ensemble with naive Bayes were shown to have higher prognostic performance (AUC: 0.92, 95% CI: 0.85-0.99, AUC: 0.90, 95% CI: 0.81-0.98, and AUC: 0.89, 95% CI: 0.82-0.97), respectively. Coronary artery calcium score (CACS) had the highest correlation with MACE.

CONCLUSION

Compared to the conventional scoring system, ML models using CCTA scans show improved prognostic prediction for MACE. Anatomical features were more important than clinical characteristics.

Clinical Outcomes of 141 Cases of Isolated Antenatal Hydronephrosis; An Observational Study

INTRODUCTION

Hydronephrosis, a condition that is mostly congenital, is considered as the most common type of pediatric urinary tract disorder. The aim of this study was the evaluation of the prognosis and outcomes of hydronephrosis in cases of congenital hydronephrosis.

METHODS

In a cross-sectional study, run in a tertiary clinic of pediatric nephrology, from 2015 to 2020, patients with fetal hydronephrosis were selected. Ultrasonography, urinalysis and kidney function tests were ordered for all patients and in the presence of hydronephrosis, repeated ultrasonography, voiding cystourethrography and dimercaptosuccinic acid scan were performed. In cases with evidence of obstruction, a diethylenetriamine pentaacetic acid scan and relative surgical procedures were performed.

RESULTS

Among 141 cases, mean age was 8 ± 1.4 years and 80.9% were male. Partial or complete obstruction in the right and left kidney was found in 16.3 and 24.8% of patients, respectively. The degree of hydronephrosis was mild in 46.1%, moderate in 39%, and severe in 9.2% of the patients. At the last follow-up period, hydronephrosis recovered in 46% of the patients, while 54% experienced persistence or exacerbation of the disease. Meanwhile, 7.1% of patients showed neurogenic bladder, 19.1% urinary tract infection and 22.7% urinary stones.

CONCLUSION

Our study revealed that fetal hydronephrosis ends in complete recovery following birth in 46% of the cases. However, in cases experiencing persistent or exacerbating hydronephrosis, optimized treatment and/or surgical intervention are required.  DOI: 10.52547/ijkd.6516.

Effects of local intraoperative epidural use of triamcinolone acetonide-soaked Gelfoam on postoperative outcomes in patients undergoing posterolateral lumbar spinal fusion surgery: a randomized, placebo-controlled, double-blind trial

OBJECTIVE

Prior evidence has supported the use of local intraoperative epidural steroids in lumbar discectomy for improvements in postoperative pain and outcomes. However, currently there is a paucity of data regarding the efficacy of local epidural steroids in spinal fusion procedures. The present investigation aimed to evaluate the impact of local epidural administration of triamcinolone acetonide-soaked Gelfoam on postoperative pain and patient-reported outcomes in patients undergoing instrumented posterolateral lumbar spinal fusion.

METHODS

In this randomized, double-blind, placebo-controlled trial, patients were randomly divided into two groups (treatment and control). Patients in the treatment group received a Gelfoam carrier soaked in 1 ml of triamcinolone acetonide (40 mg), which was placed over the nerve roots in the epidural space before the closure. Patients in the control group received a Gelfoam carrier soaked in normal saline in a similar fashion to the treatment group. Patients were followed up during their hospital stay and at 4 and 12 weeks postoperatively. The primary outcome measure was early postoperative visual analog scale (VAS) scores for pain both at rest and with movement.

RESULTS

A total of 100 patients were recruited in this study and were randomly allocated to the treatment or control group. No significant difference was found in baseline demographic, clinical, and surgical characteristics between the two groups. Postoperative VAS scores for pain both at rest and with movement were comparable between the treatment and control groups. Cumulative morphine consumption, length of hospital stay, and incidence of postoperative complications such as surgical site infection were also similar between the two groups. There was no significant difference in patient-reported outcomes including VAS scores for back and leg pain as well as the Oswestry Disability Index at 4 and 12 weeks postoperatively. The proportion of patients who achieved a minimum clinically important difference for patient-reported outcomes were also similar between the two groups.

CONCLUSIONS

In contrast to the existing literature on the beneficial use of local intraoperative epidural steroids in conventional lumbar discectomy, the present study did not demonstrate such significant efficacy for the use of local epidural steroids in instrumented posterolateral lumbar spinal fusion. However, there is still a lack of evidence in this regard and further high-quality clinical trials are required to evaluate the efficacy of local epidural steroids in this group of patients.

The Impact of the Coronavirus Disease 2019 Pandemic on Neurosurgical Practice and Feasibility of Safe Resumption of Elective Procedures During this Era in a Large Referral Center in Tehran, Iran: An Unmatched Case-Control Study

Objective

The coronavirus disease 2019 (COVID-19) pandemic has considerably affected surgical practice. The present study aimed to investigate the effects of the pandemic on neurosurgical practice and the safety of the resumption of elective procedures through implementing screening protocols in a high-volume academic public center in Iran, as one of the countries severely affected by the pandemic.

Methods

This unmatched case-control study compared 2 populations of patients who underwent neurosurgical procedures between June 1, 2019 and September 1, 2019 and the same period in 2020. In the prospective part of the study, patients who underwent elective procedures were tested for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection postoperatively to evaluate the viability of our screening protocol.

Results

Elective and emergency procedures showed significant reduction during the pandemic (59.4%, n = 168 vs. 71.3%, n = 380) and increase (28.7%, n = 153 vs. 40.6%, n = 115, respectively; P = 0.003). The proportional distribution of neurosurgical categories remained unchanged during the pandemic. Poisson regression showed that the reduction in total daily admissions and some categories, including spine, trauma, oncology, and infection were significantly correlated with the pandemic. Among patients who underwent elective procedures, 0 (0.0%) and 26 (16.25%) had positive test results on days 30 and 60 postoperatively, respectively. Overall mortality was comparable between the pre–COVID-19 and COVID-19 periods, yet patients with concurrent SARS-CoV-2 infection showed substantially higher mortality (65%).

Conclusions

By implementing safety and screening protocols with proper resource allocation, the emergency care capacity can be maintained and the risk minimized of hospital-acquired SARS-CoV-2 infection, complications, and mortality among neurosurgical patients during the pandemic. Similarly, for elective procedures, according to available resources, hospital beds can be allocated for patients with a higher risk of delayed hospitalization and those who are concerned about the risk of hospital-acquired infection can be reassured.

The association between infection burden in Iranian patients with acute myocardial infarction and unstable angina

AIM

to evaluate the association of ischemic heart disease (IHD) with the number of pathogens (infection burden) among individuals with infection.

METHODS

a total of 120 patients with IHD as the acute myocardial infarction (AMI; n=60) or unstable angina (UA; n=60) group and 60 healthy subjects with sex- and age-matched as control group were enrolled in this study. Serum samples of all participants were tested for the presence of antibodies to Helicobacter pylori (H. pylori), cytomegalovirus (CMV), type-1 herpes simplex virus (HSV-1) and type- 2 HSV (HSV-2) by using ELISA.

RESULTS

Regarding the association of the infection burden with IHD, the prevalence ratios and 95% confidence intervals (CI) were 3.18 (CI: 1.50-6.72; P<0.001) for 3 seropositivities and 3.83 (CI: 0.84-17.43; P<0.05) for 4 seropositivities. The rate of subjects with high infection burden (3 seropositivities) was significantly higher in IHD group as compared to control group (53.4% vs 21.6%; P<0.01). Moreover, the mean number of seropositivities was also significantly higher in patients with IHD in comparison to control group (2.47 vs 1.68; P<0.01). The seroprevalence of anti-H. pylori antibodies in AMI and UA groups was significantly higher compared to control group (P<0.0001). The seroprevalence of anti-CMV antibodies in AMI and UA group was also significantly higher than those observed in control group (P<0.01). Moreover, the seroprevalence of anti-HSV-1 antibodies was significantly higher in AMI and UA groups in comparison to control group (P<0.001). The seroprevalence of anti-HSV-2 antibodies was similarly expressed in patients and healthy control group.

CONCLUSION

the infection burden was significantly higher in patients with IHD, which represent that the parameter should also be considered as an independent risk factor for development of IHD. The seroprevalence of H. pylori, CMV and HSV-1 were also higher in patients with IHD.

Serum concentrations of Helicobacter pylori IgG and the virulence factor CagA in patients with ischaemic heart disease

To compare the serum concentrations of IgG to Helicobacter pylori and its virulence factor CagA in patients with ischaemic heart disease (IHD), we recruited 120 patients with IHD [acute myocardial infarction (AMI) (n = 60); unstable angina (UA) (n = 60)] and 60 sex- and age-matched healthy controls in this study. The seroprevalence of anti-H. pylori IgG was 86.7% in AMI, 91.7% in UA patients and 58.3% in the control group with mean titres of 33.2 U/ml [standard error (SE) 4.76], 57.96 U/ml (SE 7.54) and 25.72 U/ml (SE 4.01) respectively. The seroprevalence of anti-H. pylori in the patient groups was significantly higher than the control group. The mean levels of anti-H. pylori in the AMI and UA groups were also significantly higher than in the control group. The seroprevalence and mean titre of anti-CagA IgG did not differ significantly between patient and control groups.

Exploring the phase space of the quantum delta-kicked accelerator

We experimentally explore the underlying pseudoclassical phase space structure of the quantum delta-kicked accelerator. This was achieved by exposing a Bose-Einstein condensate to the spatially corrugated potential created by pulses of an off-resonant standing light wave. For the first time quantum accelerator modes were realized in such a system. By utilizing the narrow momentum distribution of the condensate we were able to observe the discrete momentum state structure of a quantum accelerator mode and also to directly measure the size of the structures in the phase space.

Ultrastructural immunolocalization of basic fibroblast growth factor in mast cell secretory granules. Morphological evidence for bfgf release through degranulation

We previously reported that mast cells (MCs) serve as a source of basic fibroblast growth factor (bFGF), a potent angiogenic and mitogenic polypeptide, suggesting that bFGF may mediate MC-related neovascularization and fibroproliferation. Unlike many other growth factors, bFGF lacks a classic peptide sequence for its secretion, and the mechanism(s) for its release remains controversial. Because MCs release a wide spectrum of bioactive products via degranulation, we hypothesized that MC degranulation may be a mechanism of bFGF release and used ultrastructural immunohistochemistry to test the hypothesis. We reasoned that if bFGF is released through degranulation, it should be localized to MC secretory granules. Human tissues with chronic inflammation and rat/mouse tissues with anaphylaxis were studied. In all tissue samples examined, positive staining (or immunogold particle localization) for bFGF in MCs was predominantly in the cytoplasmic granules. Moderate bFGF immunoreactivity was also found in the nucleus, whereas the cytosol and other subcellular organelles exhibited minimal immunogold particle localization. In contrast, no immunogold particle localization for bFGF was observed in lymphocytes or plasma cells. In rat/mouse lingual tissue undergoing anaphylaxis, immunogold particle localization for bFGF was found not only in swollen cytoplasmic granules but also in the extruded granules of MCs. Three different anti-bFGF antibodies gave similar immunogold particle localization patterns, whereas all controls were negative. These results provide morphological evidence suggesting that, despite the lack of a classic secretory peptide in its structure, bFGF is localized to the secretory granules in MCs and may be released through degranulation.

Synthesis of basic fibroblast growth factor by murine mast cells. Regulation by transforming growth factor beta, tumor necrosis factor alpha, and stem cell factor

BACKGROUND

Mast cells (MC) are involved in a wide spectrum of disorders characterized by neovascularization and fibroproliferation. We and others recently reported that human MC are a source of basic fibroblast growth factor (b FGF-2), a potent angiogenic and mitogenic polypeptide, in several disease conditions, such as chronic inflammation, hemangioma, and benign cutaneous mastocytosis. These findings suggest that FGF-2 may be an important mediator of cell proliferation and angiogenesis associated with MC. Since MC are heterogeneous across species, it is unknown whether FGF-2 expression is a feature common to all MC, or whether FGF-2 expression by MC can be regulated. We therefore examined FGF-2 expression by MC in mouse tissue and MC lines.

METHODS

Immunostaining, RT-PCR, ELISA, immunoblot and Northern blot analyses were employed to study four murine MC lines for FGF-2 expression and its regulation by transforming growth factor-beta (TGF-beta), stem cell factor (SCF), and tumor necrosis factor-alpha (TNF-alpha).

RESULTS

Mouse tissue MC and three of four murine MC lines (CFTL-12, CFTL-15, ABFTL-3) express FGF-2 as judged by immunostaining, ELISA, Western blot and Northern blot analyses, and reverse transcription-polymerase chain reaction. While TNF-alpha appeared to downregulate FGF-2 mRNA levels, treatment with SCF or TGF-beta resulted in an increase in the expression of FGF-2 at mRNA level which can be attenuated by TNF-alpha. However, the concurrent increase in FGF-2 protein was negligible, possibly due to immaturity of these cell lines.

CONCLUSION

Expression of FGF-2 may be a ubiquitous feature of MC in other species in addition to humans, and can be selectively regulated by SCF, TGF-beta and TNF-alpha.

Mast cells are a major source of basic fibroblast growth factor in chronic inflammation and cutaneous hemangioma

Mast cells play an essential role during development of inflammation after chemical and immunological insults and have been implicated in tissue fibrosis and angiogenesis. The exact contribution of mast cells to these conditions is largely unknown. In this study, we found that a potent angiogenic and mitogenic polypeptide, basic fibroblast growth factor (bFGF), is localized to the majority of mast cells from normal skin and lung and in tissue samples characterized by fibrosis, hyperplasia, and neovascularization. Using specific antibodies to mast cell tryptase, tissue macrophage, and bFGF, we demonstrate that cytoplasmic bFGF immunoreactivity is localized to 96.8 +/- 9.6% of tryptase-positive cells in human fibrotic lung tissue (n = 10), 82.3 +/- 6.9% of tryptase-positive cells in rheumatoid synovia (n = 6), and 93.1 +/- 4.8% of tryptase-positive cells in skin hemangioma (n = 5). Moreover, these tryptase-positive cells comprise a major portion (86 to 97%) of nonvascular cells exhibiting cytoplasmic bFGF staining in these tissues. In contrast, macrophage-like cells contribute less than 10% of the bFGF-positive cells in the same samples. The specificity of the immunostaining results was supported by the finding that cultured human mast cells (HMC-1) express both bFGF mRNA and protein. Our data indicate that mast cells, a primary source of heparin, also serve as a significant source of a heparin-binding growth factor, bFGF, in these disease processes. These observations suggest that mast cells may contribute to these pathological conditions by releasing this polypeptide.

Expression of basic fibroblast growth factor in synovial tissue from patients with rheumatoid arthritis and degenerative joint disease

BACKGROUND

Recent studies have implicated polypeptide growth factors in the development of rheumatoid arthritis (RA), which is characterized by synoviocyte hyperplasia and neovascularization. One such polypeptide, basic fibroblast growth factor (bFGF), is of particular interest because of its potent mitogenic and angiogenic activities. We have previously reported that cultured human synoviocytes synthesize and bind bFGF and also proliferate in response to it (1). Recently, we found a close association between increased bFGF expression and destructive changes in arthritic joints from rats (2). Now we extend our study by detecting in vivo expression of bFGF in human synovial tissues obtained from patients with RA.

EXPERIMENTAL DESIGN

Human synovial tissues from patients with RA, degenerative joint disease (DJD), and trauma were collected during joint surgery. The expression of bFGF protein and mRNA by the synovia was examined by immunolocalization, Western blot, Northern blot, and RNase protection assays. Synovium from patients with DJD and trauma was used to compare with rheumatoid synovium. Double immunostaining with cell type-specific antibodies was carried out to identify cellular sources of bFGF.

RESULTS

Both polypeptide and mRNA for bFGF were detected in the synovial samples examined. Increased bFGF staining was found in synovium-cartilage interface where joint destruction occurred and in hyperplastic synoviocytes of a subset of rheumatoid synovium. Strong cytoplasmic bFGF staining was localized in the majority of mast cells and vascular cells.

CONCLUSIONS

Synovial tissue from patients with RA, DJD, and trauma express bFGF. Increased bFGF staining in the hyperplastic lining synoviocytes and at the pannus-cartilage interface suggests that bFGF may play a role in synovial hyperplasia and joint destruction. Strong cytoplasmic bFGF staining found in mast cells and vascular cells indicates that these cells are the major sources of tissue bFGF.

Apoptosis in the thymus of developing Xenopus laevis

Metamorphosis in Xenopus laevis is a time when thyroxine and glucocorticoid levels rise, dramatic morphological and physiological changes take place, and tolerance is established to newly expressed adult antigens. In vitro exposure of thymocytes tested at different metamorphic stages, to the T-cell lectin, phytohemagglutinin (PHA), stimulates increased apoptosis, but incubation with the synthetic glucocorticoid, dexamethasone (DEX), fails in this regard. Altered-self antigenicity, following trinitrobenzene sulfonic acid (TNBS) treatment, increases apoptosis only in the late stages of metamorphosis. Developmentally blocked metamorphosing larvae demonstrate low thymic apoptotic rates that are also unaffected by in vitro exposure to DEX or by in vivo exposure to thyroxine, but are increased by PHA and in some individuals by TNBS. When released from blockade, their thymic apoptotic rates rise as progress through metamorphosis is renewed. Larval thymic apoptosis is glucocorticocoid- and thyroxine insensitive, but is lectin and altered-self antigen activated, particularly during postclimax stages.

Apoptosis in thymus of adult Xenopus laevis

Thymocyte apoptosis in adult Xenopus laevis is demonstrated on agarose gels and is quantified by propidium iodide incorporation using flow cytometry. Basal apoptotic levels are increased after in vitro exposure to a glucocorticoid, dexamethasone (DEX), and to the lectin, phytohemagglutinin (PHA). To determine the role that newly introduced antigenic determinants may play in this regard, a repertoire of altered-self antigens was created by exposing thymuses in vitro to trinitrobenzene sulfonic acid (TNBS) thereby derivatizing self-cells and proteins via 2,4,6-trinitrophenyl-acetic acid conjugation. An increase in apoptosis in TNBS-treated thymuses is observed. Thus, the thymocytes of adult Xenopus laevis are susceptible to apoptosis when induced by a glucocorticoid, a lectin, and by altered self, antigen activation.