Targeting TACC3 Induces Immunogenic Cell Death and Enhances T-DM1 Response in HER2-Positive Breast Cancer

Trastuzumab emtansine (T-DM1) was the first and one of the most successful antibody-drug conjugates (ADC) approved for treating refractory HER2-positive breast cancer. Despite its initial clinical efficacy, resistance is unfortunately common, necessitating approaches to improve response. Here, we found that in sensitive cells, T-DM1 induced spindle assembly checkpoint (SAC)-dependent immunogenic cell death (ICD), an immune-priming form of cell death. The payload of T-DM1 mediated ICD by inducing eIF2α phosphorylation, surface exposure of calreticulin, ATP and HMGB1 release, and secretion of ICD-related cytokines, all of which were lost in resistance. Accordingly, ICD-related gene signatures in pretreatment samples correlated with clinical response to T-DM1-containing therapy, and increased infiltration of antitumor CD8+ T cells in posttreatment samples was correlated with better T-DM1 response. Transforming acidic coiled-coil containing 3 (TACC3) was overexpressed in T-DM1-resistant cells, and T-DM1 responsive patients had reduced TACC3 protein expression whereas nonresponders exhibited increased TACC3 expression during T-DM1 treatment. Notably, genetic or pharmacologic inhibition of TACC3 restored T-DM1-induced SAC activation and induction of ICD markers in vitro. Finally, TACC3 inhibition in vivo elicited ICD in a vaccination assay and potentiated the antitumor efficacy of T-DM1 by inducing dendritic cell maturation and enhancing intratumoral infiltration of cytotoxic T cells. Together, these results illustrate that ICD is a key mechanism of action of T-DM1 that is lost in resistance and that targeting TACC3 can restore T-DM1-mediated ICD and overcome resistance.

SIGNIFICANCE

Loss of induction of immunogenic cell death in response to T-DM1 leads to resistance that can be overcome by targeting TACC3, providing an attractive strategy to improve the efficacy of T-DM1.

Reviving immunogenic cell death upon targeting TACC3 enhances T-DM1 response in HER2-positive breast cancer

Immunogenic cell death (ICD), an immune-priming form of cell death, has been shown to be induced by several different anti-cancer therapies. Despite being the first and one of the most successful antibody-drug conjugates (ADCs) approved for refractory HER2-positive breast cancer, little is known if response and resistance to trastuzumab emtansine (T-DM1) involves ICD modulation that can be leveraged to enhance T-DM1 response. Here, we report that T-DM1 induces spindle assembly checkpoint (SAC)-dependent ICD in sensitive cells by inducing eIF2α phosphorylation, surface exposure of calreticulin, ATP and HMGB1 release, and secretion of ICD-related cytokines, all of which are lost in resistance. Accordingly, an ICD-related gene signature correlates with clinical response to T-DM1-containing therapy. We found that transforming acidic coiled-coil containing 3 (TACC3) is overexpressed in T-DM1 resistant cells, and that T-DM1 responsive patients have reduced TACC3 protein while the non-responders exhibited increased TACC3 expression during T-DM1 treatment. Notably, genetic or pharmacological inhibition of TACC3 revives T-DM1-induced SAC activation and induction of ICD markers in vitro. Finally, TACC3 inhibition elicits ICD in vivo shown by vaccination assay, and it potentiates T-DM1 by inducing dendritic cell (DC) maturation and enhancing infiltration of cytotoxic T cells in the human HER2-overexpressing MMTV.f.huHER2#5 (Fo5) transgenic model. Together, our results show that ICD is a key mechanism of action of T-DM1 which is lost in resistance, and that targeting TACC3 restores T-DM1-mediated ICD and overcomes resistance.

TCR-NK Cells: A Novel Source for Adoptive Immunotherapy of Cancer

Antigen-specific retargeting of cytotoxic lymphocytes against tumor-associated antigens has thus far remained largely dependent on chimeric antigen receptors (CARs) that can be constructed by the fusion of an extracellular targeting domain (classically a single-chain variable fragment from an antibody) fused with intracellular signaling domains to trigger activation of T or natural killer (NK) cells. A major limitation of CAR-based therapies is that this technology only allows for the targeting of antigens that would be located on the surface of target cells while non-surface antigens, which affect approximately three-fourths of all human genes, remain out of reach. The targeting of non-surface antigens is only possible using inherent T cell receptor (TCR) mechanisms. However, introducing a second TCR into T cells via genetic modification is problematic due to the heterodimeric nature of the TCR ligand-binding domain, which is composed of TCR α and β chains. It has been observed that the delivery of a second TCR α/β pair may lead to the mispairing of new TCR chains with the endogenously expressed ones and create mixed TCR dimers, and this has negatively affected the advancement of TCR-based T cell therapies. Recently, NK cells have been put forward as possible effectors for TCR gene therapy. Since NK cells do not endogenously express TCR chains, this seems to be an infallible approach to circumventing the problem of mispairing. Moreover, the similarity of intracellular signaling pathways and mechanisms of cytotoxicity between NK and T cells ensures that the triggering of antigen-specific responses by the TCR/CD3 complex can be used to induce antigen-specific cytotoxicity by TCR-modified NK (TCR-NK) cells. This review provides an overview of the initial studies of TCR-NK cells, identifies open questions in the field, and defines the place of this approach within the spectrum of adoptive immunotherapy techniques that rely on cytotoxic lymphocytes.

TCR-NK Cells: A Novel Source for Adoptive Immunotherapy of Cancer

Antigen-specific retargeting of cytotoxic lymphocytes against tumor-associated antigens has so far remained largely dependent on chimeric antigen receptors (CARs) that can be constructed by the fusion of an extracellular targeting domain (classically an scFv fragment from an antibody) fused with intracellular signaling domains to trigger activation of T or NK cells. A major limitation of CAR-based therapies is that this technology allows only for targeting antigens that would be located on the surface of a target cell while non-surface antigens that constitute about ¾ of all human genes stay out-of-reach. The targeting of non-surface antigens is only possible by using the inherent mechanisms of the T cell receptor (TCR). However, introducing a second TCR into T cells via genetic modification has been problematic due to the heterodimeric nature of the TCR ligand-binding domain that is composed of TCR α and β chains. It has been observed that the delivery of a second TCR α/β pair to may lead to mispairing of new TCR chains with the endogenously expressed ones and create mixed TCR dimers which has negatively affected the advancement of TCR-based T cell therapies. Recently, Natural Killer (NK) cells have been put forward as effectors for TCR gene therapy. Since NK cells do not endogenously express TCR chains, this seems to be an infallible method in circumventing the mispairing problem. Moreover, the similarity of intracellular signaling pathways and mechanisms of cytotoxicity between NK and T cells makes sure that the triggering of antigen-specific responses by the TCR/CD3 complex can be used to induce antigen-specific cytotoxicity by TCR-modified NK cells (TCR-NK). This review aims to overview the initial studies on TCR-NK cells, identify open questions in the field and define its place within the spectrum of adoptive immunotherapy approaches that rely on cytotoxic lymphocytes.

Coronary artery disease and revascularization associated with immune checkpoint blocker myocarditis – report from an international registry

Purpose

Immune-checkpoint-blocker (ICB) associated myocarditis (ICB-myocarditis) may present similarly and/or overlap with other cardiac pathology including acute coronary syndrome presenting a challenge for prompt clinical diagnosis.

Methods

An international registry was used to retrospectively identify cases of ICB-myocarditis. Presence of coronary artery disease (CAD) was defined as coronary artery stenosis >70% in patients undergoing coronary angiogram.

Results

Among 261 patients with clinically suspected ICB-myocarditis who underwent a coronary angiography, CAD was present in 59/261 (22.6%) (Table 1). Coronary revascularization was performed during the index hospitalization in 19/59 (32.2%) patients. Patients undergoing coronary revascularization less frequently received steroids administration within 24h of admission compared to the other groups (p=0.029). Myocarditis related 90-day mortality was 9/17 (52.7%) in the revascularized cohort, compared to 5/31 (16.1%) in those not revascularized and 25/156 (16.0%) in those without CAD (p=0.001). irAE-related 90-day mortality was 9/17 (52.7%) in the revascularized cohort, compared to 6/31 (19.4%) in those not revascularized and 31/156 (19.9%) in no CAD groups (p=0.007) (Figure 1). All-cause 90-day mortality was 11/17 (64.7%) in the revascularized cohort, compared to 13/31 (41.9%) in no revascularization and 60/158 (38.0%) in no CAD groups (p=0.10). After adjustment on age and sex, coronary revascularization remained associated with ICB-myocarditis-related death at 90 days (Hazard ratio [HR]=4.03, 95%confidence interval [CI] 1.84–8.84, p<0.001) and was marginally associated with all-cause death (HR=1.88, 95% CI 0.98–3.61, p=0.057).

Conclusion

CAD may exist concomitantly with ICB-myocarditis and portend a poorer outcome when revascularization is performed. This is potentially mediated thru delayed diagnosis and treatment or more severe presentation of ICB-myocarditis.

Funding Acknowledgement

Type of funding sources: None.

Contemporary Sterilization Protocols of Healing Abutments for Reusability: A Systematic Review

INTRODUCTION

Although healing abutments are designated for single use by most implant manufacturers, it is common practice for clinicians to reuse healing abutments. However, there is a lack of adequate references that describe detailed sterilization protocols for reuse of healing abutments.

OBJECTIVES

The purpose of this systematic review was to compile, organize, and describe the most common techniques for the sterilization of healing abutments and their efficiency in eliminating traces of microorganisms.

METHODS

An electronic search in 5 different databases was performed, including the National Library of Medicine (MEDLINE via PubMed), Embase, Cochrane Central Register of Controlled Trials, Web of Science, and Google Scholar from January 2000 to December 2020. Search variables included were dental implant, healing abutment, contaminate, contamination, reuse, and sterilization. Studies reporting with a minimum sample size of 10 healing abutments (5 per group) published in the English language were evaluated. Risk of bias assessment was elaborated for included investigations.

RESULTS

In total, 812 articles were identified, of which 8 were included in the analysis. Steam autoclave was the most widely used form of resterilization. Not a single protocol, however, was able to achieve 100% virgin surface of the healing abutments.

CONCLUSION

Although reuse of dental implant healing abutments is a cost-effective measure in dental practice, thorough surface decontamination followed by resterilization is highly recommended before reuse.

KNOWLEDGE TRANSFER STATEMENT

With consideration of cost and patient preference, results of this review would be useful in knowing various sterilization protocols for reusing healing abutments that could lead to more appropriate therapeutic decisions.

The value of parathyroid scintigraphy on lesion detection in patients with normocalcemic primary hyperparathyroidism

OBJECTIVE

Primary hyperparathyroidism (PHPT) is one of the most frequent endocrine diseases. Most of the patients with PHPT are asymptomatic, and only 20% of them become symptomatic with increasing levels of calcium. It has been reported that normocalcemic primary hyperparathyroidism (NPHPT) may be the incipient period of PHPT where calcium (Ca) levels are in normal range, and it may advance to overt PHPT. Early diagnosis of PHPT is important in order to prevent its complications. In this retrospective study, we aimed to evaluate the role of 99mTc-MIBI parathyroid scintigraphy on lesion detection in patients with NPHPT.

MATERIAL AND METHODS

The parathyroid scintigraphy database was reviewed retrospectively in patients with PHPT. 117 patients who underwent 99mTc-MIBI scintigraphy were recruited to the study. Serum calcium level above 10.5mg/dl was considered as hypercalcemia.

RESULTS

A total of 117 patients' (female/male:98/19) mean serum PTH levels (mean±SD) were 149±97 pg/ml in normocalcemic group (Ca:9.6±0.6mg/dL, n:38) and 189±135 pg/ml in hypercalcemic group (Ca:11.4±0.6mg/dL, n:79) (p:0.072). The sex and ages were not different between the scintigraphy positive and negative groups, but the lesion detection rates with parathyroid scintigraphy were 42% in normocalcemic group and 81% in hypercalcemic group (p<0.0001).

CONCLUSIONS

Several factors including serum Ca, the imaging protocol, existence of multiglandular disease, the size and MIBI biokinetics of the adenoma may influence lesion detectability in parathyroid scintigraphy. Although high serum Ca level is an important parameter in predicting its success, parathyroid scintigraphy remains a valuable diagnostic method even in patients with NPHPT.

Targeting Adenosine with Adenosine Deaminase 2 to Inhibit Growth of Solid Tumors

Extracellular adenosine in tumors can suppress immune responses and promote tumor growth. Adenosine deaminase 2 (ADA2) converts adenosine into inosine. The role of ADA2 in cancer and whether it can target adenosine for cancer therapy has not been investigated. Here we show that increased ADA2 expression is associated with increased patient survival and enrichment of adaptive immune response pathways in several solid tumor types. Several ADA2 variants were created to improve catalytic efficiency, and PEGylation was used to prolong systemic exposure. In mice, PEGylated ADA2 (PEGADA2) inhibited tumor growth by targeting adenosine in an enzyme activity-dependent manner and thereby modulating immune responses. These findings introduce endogenous ADA2 expression as a prognostic factor and PEGADA2 as a novel immunotherapy for cancer. SIGNIFICANCE: This study identifies ADA2 as a prognostic factor associated with prolonged cancer patient survival and introduces the potential of enzymatic removal of adenosine with engineered ADA2 for cancer immunotherapy.

Predictors of steroid-refractory immune checkpoint inhibitor associated myocarditis

Background/Introduction

Immune checkpoint inhibitor (ICI)-associated myocarditis has a high mortality rate of approximately 50%. Clinical decompensation often occurs despite first-line treatment with corticosteroids. Factors associated with steroid failure are currently unknown.

Purpose

To identify predictors of steroid failure in patients with ICI-associated myocarditis.

Methods

We developed a web-based registry to collect and study 157 cases with clinical manifestations of ICI-associated myocarditis across 16 countries. Steroid failure was defined as patients who were escalated to immunomodulators after ≥1mg/kg daily dose of prednisone or had in-hospital death due to myocarditis despite ≥1mg/kg daily dose of prednisone. Steroid response was defined as all other patients treated with steroids without escalation to immunomodulators and without death due to myocarditis. A multivariate logistic model accounting for age and sex was used to predict association with steroid failure.

Results

Compared to steroid responsive cases, steroid failure was more likely to result in fulminant myocarditis (56.7% vs 19.6%, OR=5.37 [2.62–10.98] p&lt;0.001) and all-cause in-hospital mortality (49.1% vs 12.9%, OR=6.50 [2.86–14.73] p&lt;0.001) with shorter time from presentation to death (27.5 vs 43.0 days HR: 2.56 [1.45–4.50] p=0.001). When adjusting for age and sex, cases were more likely to be steroid-refractory if they were female (46.7% vs 30.1%, OR=2.77 [1.31–5.85] p=0.007), higher body mass index (27.2 vs 22.0, OR=1.09 [1.01–1.18] p=0.012), had higher intake creatine kinase (2800.5 vs 528.0 U/L, OR=1.48 [1.14–1.90] p=0.003) had higher intake troponin T (1.40 vs 0.25 ng/mL OR=1.63 [1.00–2.64] p=0.049), or had one or more concomitant non-cardiac immune-related adverse event (90.0% vs 74.2%, OR=3.10 [1.14–8.25] p&lt;0.026). The only immune-related adverse events independently associated with steroid failure in myocarditis were myasthenia gravis-like syndrome (26.7% vs 8.2%, OR=3.84 [1.47–10.10] p=0.006) and myositis (45.0% vs 24.7%, OR=2.38 [1.16–4.92] p=0.018). Steroid failure was not significantly associated with cardiovascular or autoimmune history but was associated with a history of thymoma (12.0% vs 2.6%, OR=18.86 [0.10–356.7] p=0.05)

Conclusion(s)

Features such as female sex, high body mass index, and pre-existing thymoma as well as findings of elevated cardiac biomarkers and other non-cardiac immune-related adverse events – particularly myositis and myasthenia gravis-like syndrome – may represent a steroid-refractory phenotype of ICI-associated myocarditis. These results suggest that a multidisciplinary approach to diagnosing concomitant non-cardiac immune related adverse events is key to risk-stratifying ICI-associated myocarditis.

Forrest Plot

Funding Acknowledgement

Type of funding source: Private hospital(s). Main funding source(s): National Institutes of Health

Abstract A21: Engineering antigen-specific natural killer cells against the melanoma-associated antigen tyrosinase via TCR gene transfer

Introduction of chimeric antigen receptors (CARs) to natural killer (NK) cells has so far been the only practical method for specific targeting of NK cells against surface antigens. In contrast, T-cell receptor (TCR) gene therapy can supply large populations of cytotoxic T-lymphocytes (CTL) genetically modified to express a TCR that can also target intracellular antigens. However, the mispairing of endogenous and genetically transferred TCR subunits constitutes a bottleneck in the development of safe therapies as it often leads to formation of TCRs with unknown specificity. In order to overcome this obstacle and enable intracellular antigen targeting, we propose the use of NK cells for TCR gene therapy. In this study, we approach the obstacles associated with TCR gene therapy from a unique perspective that results in MHC-I-restricted epitope-specific targeting of tumors cells through expression of a functional TCR complex on NK cells. Our results show that the ectopic expression of CD3δ, CD3γ, and CD3ϵ chains along with TCR α/β gene delivery to NK cells enables the functional expression of a TCR specific to the HLA-A2-restiricted tyrosinase-derived melanoma epitope, Tyr368-379. NK cells expressing a functional TCR exhibit the capacity to degranulate in an antigen-specific manner in response to engagement of the cognate peptide/MHC ligand on target cells. In addition, upon engagement of their TCR, NK cells are fully capable of producing proinflammatory cytokines IFNγ and TNF-α, a signature mark of NK cell activation and immune cell recruitment. Finally, NK-TCR cells exhibit MHC-I-restricted antigen detection and antigen-specific lysis of tumor cells both in vitro and in vivo. Antigen-specific targeting of NK cells via TCR gene delivery stands out as a unique discovery providing a novel tool in the field of adoptive immunotherapy that can also overcome the major hurdle of “mispairing” in TCR gene therapy. Clinical trials using NK cells, including genetically modified NK cells expressing activating receptors or CARs, have clearly demonstrated a significant benefit in patients with various malignancies. The overall safety profile and promising clinical benefits of NK cells combined with the exclusive antigen specificity of the TCR, all together provide a novel approach in the design of efficient antigen-specific adoptive immunotherapy.

Citation Format: Ayhan Parlar, Ece C. Sayitoglu, Cevriye Pamukcu, Anna-Maria Georgoudaki, Didem Ozkazanc, Mertkaya Aras, Benjamin Josey, Michael Chrobok, Suzanne Branecki, Pegah Zahedimaram, Lolai Ikromzoda, Evren Alici, Batu Erman, Tolga Sutlu, Adil D. Duru. Engineering antigen-specific natural killer cells against the melanoma-associated antigen tyrosinase via TCR gene transfer [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr A21.

Engineering antigen-specific NK cell lines against the melanoma-associated antigen tyrosinase via TCR gene transfer

Introduction of Chimeric Antigen Receptors to NK cells has so far been the main practical method for targeting NK cells to specific surface antigens. In contrast, T cell receptor (TCR) gene delivery can supply large populations of cytotoxic T-lymphocytes (CTL) targeted against intracellular antigens. However, a major barrier in the development of safe CTL-TCR therapies exists, wherein the mispairing of endogenous and genetically transferred TCR subunits leads to formation of TCRs with off-target specificity. To overcome this and enable specific intracellular antigen targeting, we have tested the use of NK cells for TCR gene transfer to human cells. Our results show that ectopic expression of TCR α/β chains, along with CD3 subunits, enables the functional expression of an antigen-specific TCR complex on NK cell lines NK-92 and YTS, demonstrated by using a TCR against the HLA-A2-restricted tyrosinase-derived melanoma epitope, Tyr_368-377 . Most importantly, the introduction of a TCR complex to NK cell lines enables MHC-restricted, antigen-specific killing of tumor cells both in vitro and in vivo. Targeting of NK cells via TCR gene delivery stands out as a novel tool in the field of adoptive immunotherapy which can also overcome the major hurdle of "mispairing" in TCR gene therapy.

Esthetics in removable partial denture--a review

Removable partial denture is a repulsive modality of treatment that we still must rely upon for certain cases and is a part of the practice. But these patients expect it to look as esthetic as any other contemporary modality of treatment. This article thus focuses on the esthetic aspects that a clinician must place emphasis upon during the designing and fabrication of prosthesis to provide the desirable outcome.

Effects of ebselen on ischemia/reperfusion injury in rat brain

AIM

Interruption of blood flow may result in considerable tissue damage via ischemia/reperfusion (I/R) injury-induced oxidative stress in brain tissues. The aim of the present study was to investigate the effects of Ebselen treatment in short-term global brain I/R injury in rats.

MATERIAL AND METHODS

The study was carried out on 27 Wistar-albino rats, divided into three groups including Sham group (n = 11), I/R group (n = 8) and I/R+Ebselen group (n = 8).

RESULTS

Malondialdehyde (MDA) levels were significantly increased in I/R group in comparison with the Sham group and I/R+Ebselen group (p < 0.001 and p < 0.01). Superoxide dismutase (SOD) activity was significantly lower in I/R group in comparison to both Sham (p < 0.001) and I/R+Ebselen (p < 0.01) groups. Similarly, SOD activity was decreased in I/R+Ebselen group when compared with Sham group (p < 0.001). Sham and I/R groups were similar in terms of nitric oxide (NO) levels. In contrast, the NO level was lower in I/R+Ebselen group when compared with Sham (p < 0.001) and I/R (p < 0.01) groups. There was no significant difference among the groups in terms of glutathione peroxidase and catalase activities. In histopathological examination, the brain tissues of rats that received Ebselen showed morphological improvement.

CONCLUSION

Ebselen has neuron-protective effects due to its antioxidant properties as shown by the decrease in MDA overproduction, increase in SOD activity and the histological improvement after administration of Ebselen to I/R in brain tissue.

Effects of montelukast and methylprednisolone on experimental spinal cord injury in rats

OBJECTIVE

The development of secondary brain injury after trauma is known to involve in many cellular mediators. The aim of the study was to evaluate and compare the effects of the use of both methylprednisolone and montelukast on serum and tissue concentrations of NO, malondialdehyde (MDA) levels, superoxide dismutase (SOD) activity, and tissue glutathione peroxidase (GSH-Px) activity in rats with spinal cord injury (SCI).

MATERIALS AND METHODS

SCI was induced in Wistar albino rats by dropping a 10 g rod from a 5.0 cm height at T9-10. The 28 rats were randomly divided into four equal groups: montelukast, methylprednisolone, non-treatment and sham groups. Rats were neurologically tested at 24 hours after trauma and spinal cord tissue levels of MDA, SOD, GSH-PX, CAT levels and blood CK, CK-BB, LDH levels were measured. In addition, histopathological changes were also examined.

RESULTS

There was a significant improvement in Tarlov scores in methylprednisolone and montelukast administered group compared to the trauma group (p = 0.001). When compared to trauma group, methylprednisolone and montelukast groups had significant differences in MDA (p < 0.05), SOD (p < 0.001), CK-BB (p < 0.001) and LDH (p < 0.05) levels. Histopathologically, no significant changes were observed.

CONCLUSIONS

The present study shows effects of montelukast with biochemical and histopathological parameters and compares its effects with those of methylprednisolone for the first time. Our research has shown that montelukast and methylprednisolone have a neuroprotective effect on spinal cord injury.

The effects of mobile phones on apoptosis in cerebral tissue: an experimental study on rats

INTRODUCTION

The concern about mobile phone effects is increasing as the number of users increasing too. Different studies have different results, so this topic is still open to discussion. Aim of this report was to investigate the effects of the mobile phones on the Bcl-2 gene and p53 proteins in rat brains.

MATERIALS AND METHODS

In the study group of 10 rats; mobile phones that spread EMW at a frequency between 1900-2100 MHz and Specific Absorption Rate range between 0.005 W/kg and 0.288 W/kg (Dialing mode), 0.004 W/kg and 0.029 W/kg (Calling mode) were attached to rat ears for simulating usage in daily life for 7 times a day during 5 minutes (3 seconds dialing mode, 4 minutes and 47 seconds of calling mode) for a four week period. Sham group (n=10) rats were only immobilized without EMW exposure. Another group of rats (n=10) were counted as control without any application. immunohistopathological examination was performed for p53 and Bcl-2 expression.

RESULTS

Immunohistopathological examinations revealed that the samples in the study group had more p53 and Bcl-2 positive stained cells and they were stained denser. In both evaluations, these differences between the study and control group were found statistically significant (p < 0.003); In Bcl-2 evaluation statistically significant difference was found between study and sham group to (p < 0.005); however, the p53 evaluation between the study and the sham group did not show any statistically significant difference (p > 0.005).

CONCLUSIONS

Our results showed that the electro-magnetic waves emitted by the mobile phones may have effect on apoptosis. Besides, obtained data revealed that more realistic application of mobile phones during experiments is more important as expected.

A medically treated multiple cerebral hydatid cyst disease

Echinococcosis is a potentially fatal parasitic disease that can affect many animals and humans. The disease results from infection by tapeworm larvae of the genus Echinococcus--notably, E. granulosus, E. multilocularis, E. vogeli andE. oligarthrus. Cyst hydatid disease is usually seen in adults, and mainly affects liver and/or lungs (90%). Cerebral involvement is very rare (1-3%), and more common in children. Therapy consists of medical treatment and surgical intervention if it is possible. The authors report the case of a 55-year-old male patient with multiple intracranial hydatid cysts, who was successfully treated with albendazole (10 mg/kg/day) alone without any surgical intervention.

Indicators of Acute Rejection on Tc-99m DTPA Renal Scintigraphy

INTRODUCTION

Specific criteria for diagnosing an acute rejection episode (ARE) are not present on renal scintigraphy. However, a deterioration in renal function observed on serial imaging is suggestive of an ARE during the early posttransplantation period. In this study, we evaluated Tc-99m DTPA renal scintigraphy findings among patients with renal allograft dysfunction. The aim was to define criteria for ARE on a single imaging study alone.

MATERIALS AND METHODS

This study included 82 patients with renal allograft dysfunction, each of whom had a specific biopsy-proven pathology. From the background-corrected Tc-99m DTPA renal time-activity curves, the following parameters were computed: the ratio of counts at peak perfusion to that at plateau (P:PL) and the ratio of counts at peak perfusion to that at peak uptake (P:U). The images were inspected visually for excretion patterns and other morphological changes.

RESULTS

A specific renogram pattern, that is an increase in perfusion to uptake ratio together with a nearly flat uptake curve and preserved peak/plateau pattern, was observed in 67% of low-grade AREs. In contrast, a flat uptake curve usually occurred together with a loss of peak/plateau pattern in a high-grade ARE. The findings that were highly specific for ARE on visual inspection were little or no collecting system activity, pelvic hypoactivity, and indistinctness of the corticomedullary junction.

CONCLUSIONS

Our results indicate that in low-grade ARE, there is decreased filtration relative to perfusion as evidenced by a decrease in the perfusion-to-uptake ratio with loss of a peak/plateau pattern. A hypoactive pelvis with little activity in the collecting systems may be due to edema in the renal interstitium and pelvicalyceal structures.

Comparison of Tc-99m DTPA and Tc-99m MAG3 Perfusion Time-Activity Curves in Patients With Renal Allograft Dysfunction

AIM

The perfusion time-activity curve on DTPA renal scintigraphy shows a peak and plateau pattern which is usually absent or less marked when using tubular agents such as MAG3. The exact mechanism that results in this difference between the two tracers is not well understood. A descending pattern on MAG3 has been proposed to be due to decreased extraction. In this study we compared the diagnostic utility of perfusion patterns obtained with DTPA and MAG3 among patients with renal allograft dysfunction.

MATERIALS AND METHODS

This study included 48 patients with renal allograft dysfunction and 18 recipients with normal graft function. Every recipient had renal scintigraphy with Tc-99m MAG3 and Tc-99m DTPA 1 day apart. The second phase of the perfusion curve after the initial rise was classified as ascending, flat, or descending. In patients with a descending curve on DTPA study, we calculated the ratio of counts at peak perfusion to that at plateau (P:PL). Impaired perfusion was based on a deterioration of the peak-to-plateau pattern on DTPA and the presence of a flat-descending curve on MAG3.

RESULTS

In patients with dysfunction, impaired perfusion was observed in 77% of DTPA and in 54% of MAG3 studies. A flat-descending curve on MAG3 was present in 44% of patients with normal graft function. By MAG3, 67% of acute rejection and 28% of chronic allograft nephropathy (CAN) cases showed deteriorated perfusion. The corresponding values for DTPA were 67% and 94%, respectively. A flat-ascending pattern on DTPA was more frequent in CAN than it was in acute rejection (33% and 17%, respectively).

CONCLUSION

The sensitivity of DTPA perfusion pattern for diagnosing dysfunction was significantly greater than that for MAG3. Our results suggest that the major determinant of a curve pattern on DTPA or MAG3 study is the extraction relative to perfusion. Thus for patients with CAN, extraction is higher relative to perfusion, resulting in a lower P:PL ratio or an ascending curve on DTPA. Although the extraction of DTPA is less than that of MAG3, this level of extraction renders DTPA more sensitive to serial changes in renal function and pathophysiological mechanisms related to kidney function.

The Significance of Tc-99m DTPA Renal Scintigraphy for the Demonstration of Progressive Functional Changes That Accompany Chronic Allograft Nephropathy

OBJECTIVES

Chronic allograft nephropathy (CAN) is usually progressive; its natural course can only be modified in the initial stages. In this study, we graded Tc-99m diethylenetriaminepentaacetic acid (DTPA) renogram curves with respect to the perfusion/uptake pattern and correlated these findings with biopsy results in patients with CAN.

METHODS

This study included 63 renal allograft recipients with biopsy-proven CAN. The agent used for renal scintigraphy was Tc-99m DTPA. Quantitative evaluation of perfusion included calculation of the ratio of peak perfusion counts divided by plateau counts (P:PL). Deterioration of renal function was accompanied with a gradual loss of a peak and plateau pattern. For the evaluation of uptake in relation to perfusion pattern, we graded the renogram curves into four based on the presence of a peak and plateau pattern and the presence of an uptake peak.

RESULTS

In patients with CAN, the mean P:PL was significantly lower than that of the control group. The serial changes in successive grades of CAN in respect to uptake-perfusion pattern was a gradual loss of peak and plateau pattern followed by a decline in uptake. In recipients with high-grade CAN, an uptake peak was absent.

CONCLUSIONS

Evaluation of Tc-99m DTPA time-activity curves revealed a progressive change in perfusion-uptake pattern in patients with CAN. According to our results, deterioration of perfusion preceded the decline in uptake. Serial renogram changes are thought to reflect initial hypoperfusion followed by increased intraglomerular pressure and finally glomerulosclerosis. These findings have implications for the pathophysiology and management of CAN.

Photorefractive keratectomy retreatments for regression. One-year follow-up

PURPOSE

Ninety eyes were retreated to correct myopic regression, with or without corneal haze, after primary photorefractive keratectomy (PRK); astigmatism ranging from -0.50 to -3 diopters (D) was present in 43 eyes.

RESULTS

The sphere (mean +/- standard deviation) was -2.82 +/- 1.74 D before repeat surgery. At 6 months, the mean was +0.30 D; at 1 year, it was -0.17 D. Patients were divided into two groups: group 1 included 56 eyes with little or no haze (< or = 1). The mean sphere value for this group was -2.13 D before retreatment; at 1 year, it was -0.20 +/- 0.76 D. At 6 months, 84% of sphere values were within +/- 1 D of the intended correction, with a mean haze value of less than 0.5, similar to that before repeat surgery; there was a mean gain of 0.25 Snellen line of best-corrected visual acuity. Astigmatism equal or greater than -0.5 D was present in 34 eyes (mean, -1.17 +/- 0.55 D). At 6 months, astigmatism was reduced to -0.45 +/- 0.48 D. The second group included 34 eyes with corneal haze greater than 1 (mean, 2.7). The mean sphere value was -3.95 D before photorefractive keratectomy and -0.12 +/- 1.48 D 1 year after treatment. Fifty percent of the mean sphere values were within +/- 1 D at 6 months, with a mean haze value of 1. The gain in mean best-corrected visual acuity was 1.3 Snellen lines. The mean astigmatism in nine eyes was -1.75 +/- 0.75 D before photorefractive keratectomy and -0.72 +/- 0.78 D 6 months after treatment.

CONCLUSION

There is a significant difference in the outcome predictability between the two groups. A second photorefractive keratectomy can be done 6 months after the primary treatment in patients with regression with or without trace haze. This group has a High predictability in achieving a good correction, with a low complication rate. When haze is present, retreatments are less predictable with 40% of patients overcorrected. Generally, however, these eyes have a statistically significant decrease in haze (Student's t test; P < 0.01) and an improvement in best-corrected visual acuity.

Multizone/multipass photorefractive keratectomy: six month results

A multizone/multipass photorefractive keratectomy (MP-PRK) technique was used to treat 315 eyes with the 193 nm VISX 20/20 excimer laser. Algorithms were developed to treat the full range of myopia, including 170 low myopic eyes (-1.0 to -6.0 diopters [D]), 105 moderately myopic eyes (-6.0 to -10.0 D), and 40 highly myopic eyes (-10.0 to -27.0 D). Preoperative mean myopia was -6.69 D; astigmatism equal to or greater than -0.5 D (mean -1.18 D) was present in 193 eyes. At one month postoperatively, most eyes were slightly hyperopic (mean +0.8 D); this regressed to a mean of -0.16 D. At six months, 95.5% of low myopes, 84.8% of moderate myopes, and 59.5% of high myopes were within 1.0 D of emmetropia; 78.4% of high myopes were within 2.0 D of the intended correction. There was no loss of 20/40 best corrected visual acuity (BCVA) at six months; a significant gain in 20/25 BCVA was seen in the moderate and high myopia groups (P < .05). At six months, uncorrected visual acuity was 20/25 in 89.4% of low myopes, 75.0% of moderate myopes, and 25.7% of high myopes. Mean haze value was 0.48 at one month and was not significantly different among the three groups (0.44, 0.52, 0.51, respectively). A control group treated with the one-pass multizone technique had a significantly higher amount of haze: 1.05 (P < .01). The data presented compare favorably with those obtained from other centers. Based on these results, we believe that MP-PRK is a safe, reliable technique to correct most low, moderate, and high myopia.

Effect of changes in renal perfusion pressure on the suppression of proximal tubular sodium reabsorption due to saline loading

Rapid intravenous infusion of saline is known to suppress reabsorption of sodium and water in the proximal tubule. It has previously been shown that this suppression is accompanied by two changes which in combination might account for the over-all decrease in reabsorption: a reduction in the intrinsic reabsorptive capacity of the tubular epithelium (C/pir(2)) and a reduction in the ratio between tubular volume and GFR (pir(2)d/V(o)). The present micropuncture experiments were carried out in order to study the possible role of altered peritubular physical forces (hydrostatic and colloid oncotic pressure) in mediating these two changes. Proximal tubular reabsorptive capacity, transit time, fractional reabsorption of sodium and water, pir(2)d/V(o), and intratubular hydrostatic pressure were measured in saline-loaded rats during acute changes in renal perfusion pressure induced by intermittent constriction of the abdominal aorta. We found that when renal perfusion pressure was lowered to 70-90 mm Hg, the usual effects of saline loading on C/pir(2), pir(2)d/V(o), and fractional reabsorption in the proximal tubule were greatly minimized. When the aortic clamp was released and renal perfusion pressure allowed to rise, C/pir(2), pir(2)d/V(o), and fractional reabsorption fell markedly to levels characteristically seen in saline diuresis. Reclamping of the aorta reversed all of these changes. In order to determine whether the changes in C/pir(2) accompanying changes in renal perfusion pressure were mediated by a circulating natriuretic hormone, we assayed in hydopenic rats the dialysate of plasma collected from saline-loaded rats during and after release of aortic constriction by the split oil drop method. No significant difference in reabsorptive half-time (t(1/2)) was found between the two dialysates, and t(1/2) with both dialysates was approximately the same as was found when isotonic saline was injected in the tubules of hydropenic control animals. These observations suggest that the large changes in C/pir(2) which occurred with changes in renal perfusion pressure in saline-loaded rats were not mediated by a circulating hormone. We suggest that the reduction in C/pir(2), pir(2)d/V(o), and fractional reabsorption which occurs in the proximal tubule during a saline diuresis is related to the rise in hydrostatic pressure within the kidney.