Recombination-mediated PCR-directed plasmid construction in vivo in yeast

We have extended the technique of PCR-directed recombination in Saccharomyces cerevisiae to develop a simple method for plasmid or gene construction in the absence of suitable restriction sites. The DNA to be cloned is PCR-amplified with 30-40 bp of homology to a linearized yeast plasmid. Co-transformation into yeast results in homologous recombination at a position directed by the PCR oligonucleotides.

Tumor suppression by p27Kip1 and p21Cip1 during chemically induced skin carcinogenesis

p27Kip1 and p21Cip1 are cyclin dependent kinase inhibitors which can arrest cell proliferation and p27 is a tumor suppressor gene. To address the mechanism of tumor suppression by p27 and to determine if p21 has a tumor suppressor phenotype, we utilized the two stage skin carcinogenesis model on p27 and p21 knockout mice. In this model, initiation, which involves mutation of H-ras induced by DMBA, can be distinguished from promotion induced by TPA, and progression to carcinoma. The mean number of papillomas did not differ between p27-/- and control littermates, but papilloma growth rate was increased and carcinomas developed earlier. Thus, p27 deficiency did not enhance initiation, but resulted in more rapid clonal expansion of initiated cells during promotion. TPA treatment reduced p27 expression in keratinocytes also supporting a role for p27 during promotion. Tumors from p27-/- mice contained mutant H-ras indicating that p27 deficiency did not substitute for mutant ras and further, that during ras driven tumor growth, p27 is partially antagonistic since its removal led to faster growth. The treated p27-/- mice also developed intestinal adenomas. p21-/- mice did not display a significant increase in tumor numbers, growth rate or progression to carcinomas and these tumors also had mutated H-ras. Carcinomas from p21-/- mice were more poorly differentiated with a high frequency of anaplastic spindle cell carcinomas. Thus p21 deficiency mainly resulted in higher grade undifferentiated tumors.

Reduction of infarct size by intravenous injection of uncultured adipose derived stromal cells in a rat model is dependent on the time point of application

Stem cell therapy is a promising tool to improve outcome after acute myocardial infarction (AMI), but needs to be optimized since results from clinical applications remain ambiguous. A potent source of stem cells is the stromal vascular fraction of adipose tissue (SVF), which contains high numbers of adipose derived stem cells (ASC). We hypothesized that: 1) intravenous injection can be used to apply stem cells to the heart. 2) Uncultured SVF cells are easier and safer when cultured ASCs. 3) Transplantation after the acute inflammation period of AMI is favorable over early injection. For this, AMI was induced in rats by 40min of coronary occlusion. One or seven days after AMI, rats were intravenously injected with vehicle, 5×10(6) uncultured rat SVF cells or 1×10(6) rat ASCs. Rats were analyzed 35 days after AMI. Intravenous delivery of both fresh SVF cells and cultured ASCs 7 days after AMI significantly reduced infarct size compared to vehicle. Similar numbers of stem cells were found in the heart, after treatment with fresh SVF cells and cultured ASCs. Importantly, no adverse effects were found after injection of SVF cells. Using cultured ASCs, however, 3 animals had shortness of breath, and one animal died during injection. In contrast to application at 7 days post AMI, injection of SVF cells 1 day post AMI resulted in a small but non-significant infarct reduction (p=0.35). Taken together, intravenous injection of uncultured SVF cells subsequent to the acute inflammation period, is a promising stem cell therapy for AMI.

Levels of expression of P-selectin, E-selectin, and intercellular adhesion molecule-1 in coronary atherectomy specimens from patients with stable and unstable angina pectoris

Unstable angina occurs when atherosclerotic plaque ruptures. Recent evidence suggests a role for inflammation in this process. Leukocyte-endothelial cell interactions are important in inflammation and are regulated by cell adhesion molecules. This study was designed to examine the vascular expression of cell adhesion molecules and cytokines in patients with unstable angina. Directional coronary atherectomy was performed in patients with unstable and stable angina. Expression of the cell adhesion molecules P-selectin, E-selectin, and intercellular adhesion molecule-1 in the tissue obtained was examined using immunohistochemistry. In addition, expression of the cytokines tumor necrosis factor-alpha and interleukin-1beta, which participate in the regulation of cell adhesion molecule expression, was also examined. Atherectomy specimens had significantly greater P-selectin expression from patients with unstable angina than from patients with stable angina. P-selectin expression was observed primarily on endothelial cells. There were no differences in any of the other factors between patients with unstable and stable angina. In addition, other clinical and angiographic variables were not associated with differential expression of any of the cell adhesion molecules or cytokines. These results indicate a possible role for P-selectin in the process of unstable angina.

Iontophoretic delivery of oligonucleotides across full thickness hairless mouse skin

In recent years there has been an increased interest in the use of oligonucleotides as therapeutic agents. Oligonucleotide therapeutics may have significant potential over traditional drugs due to their high degree of specificity and increased affinity. The major drawbacks to the use of oligonucleotide therapeutics are the problems associated with their delivery and their relative instability in serum. The serum instability problem has been partially overcome through the use of oligonucleotides with modified backbones. Transdermal electrotransport may be used to overcome the problems associated with delivery. Here we report the use of transdermal electrotransport in the delivery of oligonucleotides across hairless mouse skin. The effects of pH, salt concentration, current density, and oligonucleotide concentration, structure, and length have been investigated.

Improving high-resolution MR bold venographic imaging using a T1 reducing contrast agent

Recently, a new imaging method was proposed by Reichenbach et al (Radiology 1997;204:272-277) to image small cerebral venous vessels specifically. This method, referred to as high-resolution blood oxygen level-dependent venography (HRBV), relies on the susceptibility difference between the veins and the brain parenchyma. The resulting phase difference between the vessels and the brain parenchyma leads to signal losses over and above the usual T2* effect. At 1.5 T, a rather long TE (roughly 40 msec) is required for this cancellation to become significant, leading to enhanced susceptibility artifacts and a long data acquisition time. In this study, we examine the utility of incorporating a clinically available T1 reducing contrast agent, Omniscan (Sanofi Winthrop Pharmaceuticals, NY, NY), with the HRBV imaging approach to reduce susceptibility artifacts and imaging time while maintaining the visibility of cerebral veins. Using a double-dose injection of Omniscan, we were able to reduce TE from 40 to 25 msec. This led to a decrease in TR from 57 to 42 msec, allowing a 26% reduction in data acquisition time while maintaining the visibility of cerebral venous vessels and reducing susceptibility artifacts. J. Magn. Reson. Imaging 1999;10:118-123, 1999.

Menstrual bleeding patterns and prevalence of bleeding disorders in a multidisciplinary adolescent haematology clinic

Heavy menstrual bleeding (HMB) is a frequent complaint in adolescence. Although HMB is often caused by immaturity of the hypothalamic-pituitary-ovarian axis, bleeding disorders are another common yet often unidentified cause. The aim of this study was to examine the bleeding patterns and prevalence of inherited bleeding disorders among females referred for HMB to a multidisciplinary adolescent haematology clinic. We retrospectively reviewed the first 105 patients (ages 8-18 years) referred to this specialty clinic from February 2009 to December 2011. Using menstrual bleeding questionnaires and medical records, data were extracted regarding demographics, bleeding patterns, frequency and types of bleeding disorders identified, and prescribed interventions. Sixty-two per cent of patients were diagnosed with a bleeding disorder, including platelet storage pool deficiency (36%), von Willebrand's disease (9%), other platelet function defect (8%), Ehlers-Danlos syndrome (7%) and combined bleeding disorders (2%). Comparison of the bleeding profiles for females with and without a bleeding disorder revealed only three factors that were significantly different, including the reported regularity of patients' periods (P = 0.02), description of period flow (P = 0.04) and number of days of each period that the bleeding was described as 'heavy' (P = 0.007). Bleeding disorders are prevalent in adolescent females presenting to a specialty clinic. Specifically, a relatively high proportion of adolescents were diagnosed with platelet storage pool deficiency. In our small population, menstrual bleeding profiles, as examined by a standardized questionnaire, could not identify females with an underlying bleeding disorder, demonstrating the important role of haemostasis testing in the evaluation of adolescents with HMB.

Neuropathology for the neuroradiologist: plaques and tangles

Histologically identified intracellular and extracellular inclusions and structures often provide a tissue diagnosis of a specific disease process. Moreover, these deposits may provide clues about the pathogenesis of the disease in which they are found. Two distinctive structures seen within the brains of patients clinically diagnosed with dementia of the Alzheimer type are extracellular plaques and intracellular neurofibrillary tangles. The purpose of this report is to review the significance of plaques and neurofibrillary tangles in the context of Alzheimer disease.

Exploring structure-activity relationships around the phosphomannose isomerase inhibitor AF14049 via combinatorial synthesis

Phosphomannose Isomerase (PMI) has been shown by genetic methods to be an essential enzyme in fungal cell wall biosynthesis. The PMI inhibitor AF14049 was discovered as an unanticipated side product from high-throughput library screening against the enzyme from C, albicans. Solid-phase synthetic methods were developed and a series of libraries and discrete analogs synthesized to explore SAR around AF14049.

Effect of intraamniotic dexamethasone administration on intestinal absorption in a rabbit gastroschisis model

Infants with gastroschisis experience delayed intestinal motility and absorption for several weeks after birth. This intestinal dysfunction is believed to occur primarily in the third trimester and to be largely caused by the prolonged exposure of the intestine to amniotic fluid. Previous studies have shown that prenatal steroid administration will enhance mucosal disaccharidase activity and nutrient uptake. The present study evaluates the effects of dexamethasone on intestinal function in a rabbit fetal gastroschisis model. Thirty-four fetuses from 10 New Zealand white rabbits were divided into three groups: (1) gastroschisis group (GSC, n = 10), gastroschisis was created on gestational day (GD) 24 (term = 31 to 33 days); (2) dexamethasone group (GSD, n = 10), after the creation of gastroschisis, a small osmotic pump was placed into the rabbit doe for dexamethasone infusion into the fetal amniotic cavity for 7 days (0.2 microgram/g/d); (3) normal group (NF, n = 10), unoperated littermates from the GSC group. There were no maternal deaths, and fetal survival rate was 85%. The fetal small intestinal disaccharidase enzyme, lactase (UE/g protein), was markedly decreased in GSC fetuses. It was increased 70% in the GSD group but lower than in normal fetuses (GSC = 10.0 +/- 1.6; GSD = 17.3 +/- 1.6 [GSD versus GSC, P < .05]; NF = 48.0 +/- 6.7). Maltase activity in the GSD group was significantly increased (GSC = 7.2 +/- 1.1; GSD = 13.9 +/- 1.8 [GSD versus GSC, P < .05]; NF = 12.2 +/- 1.3).(ABSTRACT TRUNCATED AT 250 WORDS)

Resistance to skin tumorigenesis in DNAPK-deficient SCID mice is not due to immunodeficiency but results from hypersensitivity to TPA-induced apoptosis

Scid/scid mice have a mutation in the gene encoding the catalytic subunit of DNA-dependent protein kinase (DNAPK(cs)) and are defective in end joining of DNA double-strand breaks. As a consequence, they are radiosensitive, lack mature T and B lymphocytes and are predisposed to lymphomagenesis. To determine if this DNA repair defect also increased predisposition to skin tumor formation, we treated the dorsal skin of scid/scid mice with the carcinogen 7,12-dimethylbenz[a]anthracene followed by the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA). Contrary to expectations, we observed a 5-fold reduction in skin tumor multiplicity in scid/scid mice. We addressed whether this was related to their immunodeficiency by similarly treating Rag1(-/-) and Rag2(-/-) knockout mice which also lack mature T and B lymphocytes. We observed no difference in skin tumor multiplicity for either strain compared with control littermates. This indicates a lack of a significant role for T or B lymphocyte mediated immunity on either papilloma or carcinoma formation. We observed a significant increase in apoptotic and necrotic cell death in follicular and interfollicular epithelial cells of scid/scid mice following TPA treatment. This hypersensitivity of SCID (severe combined immunodeficient) cells to TPA indicates that the resistance to skin tumor formation in scid/scid mice is due to loss of initiated cells through TPA-induced cell killing.

Syntheses of 2-alkylamino- and 2-dialkylamino-4,6-diarylpyridines and 2,4,6-trisubstituted pyrimidines using solid-phase-bound chalcones

Several substituted 2- and 4-hydroxyacetophenones are linked to Wang resin via a modified Mitsunobu protocol. These resin-bound acetophenones are condensed with aromatic aldehydes, and the resulting chalcones 5 are used for the synthesis of 2-dialkylamino- (9a-d) and 2-alkylamino-4,6-diarylpyridines (11a-f), and 2-alkyl-4,6-diaryl- (14a) and 2,4,6-triarylpyrimidines (14b,c) in a manner suitable for combinatorial applications.

Laser-triggered repetitive fluorescein angiography

Liposome-encapsulated fluorescent dye has been altered to allow full fundus angiography after a single laser shot. By exposing the retinal arteries to laser energy where they emerge at the optic disc nerve head, dye release is elicited simultaneously in all four quadrants of the retina, without choroidal fluorescence, allowing visualization of the retinal microcirculation. Because the quantity of dye release is limited, recirculation does not increase background fluorescence. The procedure can be repeated many times without delay with consistent results. Increasing the laser spot size to 1.5 mm allows consistent dye release at energy densities from 0.5 J/cm2 to 3.4 J/cm2. This refinement will allow direct comparison in primates of this technique and conventional fluorescein angiography. The laser energy delivered to the retina is below suggested levels that may be tolerated by the optic nerve.

Neuroadaptive changes in cerebellar neurons induced by chronic exposure to IL-6

IL-6 is an important signaling molecule in the CNS. CNS neurons express IL-6 receptors and their signal transduction molecules, consistent with a role for IL-6 in neuronal physiology. Research indicates that IL-6 levels are low in the normal brain but can be significantly elevated in CNS injury and disease. Relatively little is known about how the elevated levels of IL-6 affect neurons. In the current study we show that under conditions of chronic exposure, IL-6 induces alterations in the level of protein expression in developing CNS cells. Such changes may play a role in the altered CNS function observed in CNS conditions associated with elevated levels of IL-6 in the CNS.

Possible confounding effects of strobe "clicks" on flash evoked potentials in rats

Flash evoked potentials (FEPs) undergo within- and between-session changes and are modified by auditory white noise (26). We examined whether an auditory potential produced by the "click" associated with the strobe discharge could be recorded, and if alterations in an auditory response could explain the within- and between-session changes in FEPs. We also examined differences between a frontal cortex or a nasal reference electrode location on FEPs and auditory potentials. An auditory potential associated with the strobe discharge could be clearly recorded. This response was eliminated by the presence of 80 dB SPL masking white noise. However, the within- and between-session changes in FEPs could not be explained by modifications of the auditory potential. Animals whose ear drums were ruptured did not exhibit an auditory response, and their FEPs were similar to those of controls tested in the presence of masking white noise. A nasal reference electrode decreased the impact of auditory potentials on FEPs, but allow visual potentials (electroretinogram and optic tract activity) to influence FEPs. The data show that auditory potentials associated with the strobe discharge can be recorded from the visual cortex of rats, and that these auditory responses represent a possible confounding factor in the interpretation of toxicological studies employing FEPs.

Hypoxia Inducible Factor 1: A Urinary Biomarker of Kidney Disease

Identifying noninvasive biomarkers of kidney disease is valuable for diagnostic and therapeutic purposes. Hypoxia inducible factor 1 (HIF-1) expression is known to be elevated in the kidneys in several renal disease pathologies. We hypothesized that the urinary HIF-1a mRNA level may be a suitable biomarker for expression of this protein in chronic kidney disease (CKD). We compared HIF-1a mRNA levels from urine pellets of CKD and healthy subjects. To ensure that urinary HIF-1a mRNA is of kidney origin, we examined colocalization of HIF-1a mRNA with two kidney specific markers in urine cells. We found that HIF-1a mRNA is readily quantifiable in urine pellets and its expression was significantly higher in CKD patients compared with healthy adults. We also showed that the urinary HIF-1a mRNA comes primarily from cells of renal origin. Our data suggest that urinary HIF-1a mRNA is a potential biomarker in CKD and can be noninvasively assessed in patients.

Acute myocardial infarction does not affect functional characteristics of adipose-derived stem cells in rats, but reduces the number of stem cells in adipose tissue

In most pre-clinical animal studies investigating stem cell therapy in acute myocardial infarction (AMI), the administered stem cells are isolated from healthy donors. In clinical practice, however, patients who suffer from AMI will receive autologous cells, for example using adipose-derived stem cells (ASC). During AMI, inflammation is induced and we hypothesized that this might affect characteristics of ASC. To investigate this, ASC were isolated from rat adipose tissue 1 day (1D group, n = 5) or 7 days (7D group, n = 6) post-AMI, and were compared with ASC from healthy control rats (Control group, n = 6) and sham-operated rats (Sham 1D group, n = 5). We found that significantly fewer ASC were present 1 day post-AMI in the stromal vascular fraction (SVF), determined by a colony-forming-unit assay (p < 0.001 vs. Control and 7D). These data were confirmed by flow cytometry, showing fewer CD90-positive cells in SVF of the 1D group. When cultured, no differences were found in proliferation rate and cell size between the groups in the first three passages. Also, no difference in the differentiation capacity of ASC was found. In conclusion, it was shown that significantly fewer stem cells were present in the SVF 1 day post-AMI; however, the stem cells that were present showed no functional differences.

MR Imaging Differences in the Circle of Willis between Healthy Children and Adults

BACKGROUND AND PURPOSE

Asymmetries in the circle of Willis have been associated with several conditions, including migraines and stroke, but they may also be age-dependent. This study examined the impact of age and age-dependent changes in cerebral perfusion on circle of Willis anatomy in healthy children and adults.

MATERIALS AND METHODS

We performed an observational, cross-sectional study of bright and black-blood imaging of the proximal cerebral vasculature using TOF-MRA and T2 sampling perfection with application-optimized contrasts by using different flip angle evolution (T2-SPACE) imaging at the level of the circle of Willis in 23 healthy children and 43 healthy adults (4-74 years of age). We compared arterial diameters measured manually and cerebral perfusion via pseudocontinuous arterial spin-labeling between children and adults.

RESULTS

We found that the summed cross-sectional area of the circle of Willis is larger in children than in adults, though the effect size was smaller with T2-SPACE-based measurements than with TOF-MRA. The circle of Willis is also more symmetric in children, and nonvisualized segments occur more frequently in adults than in children. Moreover, the size and symmetry of the circle of Willis correlate with cerebral perfusion.

CONCLUSIONS

Our results demonstrate that the circle of Willis is different in size and symmetry in healthy children compared with adults, likely associated with developmental changes in cerebral perfusion. Further work is needed to understand why asymmetric vasculature develops in some but not all adults.

Carbon disulfide neurotoxicity in rats: VI. Electrophysiological examination of caudal tail nerve compound action potentials and nerve conduction velocity

The effects of subchronic exposure to carbon disulfide (CS2) on ventral caudal tail nerve compound nerve action potential (CNAP) amplitudes and latencies, and nerve conduction velocity (NCV) in rats were examined. Male and female Fischer 344 rats were exposed to 0, 50, 500, or 800 ppm CS2 for 6 hrs/day, 5 days/week. Using separate groups, exposure duration was 2, 4, 8, or 13 weeks. Exposure to 500 or 800 ppm CS2 for 13 weeks decreased NCV compared to the 50 ppm CS2 group. CNAP amplitudes were increased, and peak P1P2 interpeak latency decreased, after exposure to 500 or 800 ppm CS2 for 13 weeks. Most of the changes in NCV and CNAPs were not attributable to differences in tail or colonic temperature. However, the increases in peak P1 amplitude may relate to the proximity of the electrodes to the tail nerves. Assessment of tail nerve morphology after 13 weeks exposure to 800 ppm CS2 revealed only minor changes compared to the extent of axonal swelling and degeneration observed in the muscular branch of the tibial nerve and axonal swelling in the spinal cord. As anticipated, in older animals the NCV increased, the CNAP amplitudes increased, and the CNAP latencies decreased. The biological basis for the changes in CNAPs produced by CS2 is under investigation. Future studies will focus on electrophysiological evaluation of spinal nerve function, to allow better correlation with pathological and behavioral endpoints.

DNA double-strand breaks, p53, and apoptosis during lymphomagenesis in scid/scid mice

The tumor-suppressing phenotype of p53 is thought to be due to its accumulation in response to DNA damage and resultant cell cycle arrest or apoptosis. scid/scid mice are defective in DNA double-strand break repair due to a mutation in DNA-dependent protein kinase (DNAPK). Treatment of scid/scid mice with gamma radiation or N-ethyl-N-nitrosourea resulted in approximately 86% incidence of T-cell lymphomas, compared with <6% in wild-type mice. The incidence of other tumor types was not increased in scid/scid mice, suggesting that the types of DNA double-strand break that are unrepaired in these mice are not strongly carcinogenic. To determine whether mutations in DNAPK and p53 interact, we examined mice deficient in both genes. Both scid/scid p53-/- and scid/scid p53+/- mice spontaneously developed lymphomas at shorter latency than did mice with either defect alone. Loss of the wild-type p53 allele was observed in 100% of tumors from scid/scid p53 +/- mice, indicating strong selection against p53. In contrast, p53 was not inactivated in lymphomas from scid/scid p53+/+ mice. Exposure of these tumor-bearing mice to gamma radiation resulted in p53 protein accumulation and high levels of apoptosis in all tumors that were not observed in tumors from scid/scid p53+/- mice. Thus, there was a bifurcation of molecular pathways to tumorigenesis. When p53 was heterozygous in the germ line, loss of the wild-type allele occurred, and the tumors became apoptosis resistant. When p53 was wild type in the germ line, p53 was not inactivated, and the tumors remained highly apoptosis sensitive.

Conformational studies on analogs of recombinant parathyroid hormone and their interactions with phospholipids

Through the use of oligonucleotide-directed mutagenesis we have generated variants of a recombinant human parathyroid (PTH) hormone-(1-34)-homoserine (RPTH) in which a positively charged residue (Arg or Lys), a negatively charged residue (Glu), or a neutral residue (Gly) has been substituted at every position throughout the peptide. These 106 PTH analogs have been tested for their ability to stimulate cAMP production in the rat osteosarcoma cell line, UMR106. Analysis of these peptides led to the construction of several analogs containing multiple substitutions at sites of potential structural importance. Several of these analogs were shown to have 3-5-fold enhanced activity and receptor affinity. Circular dichroism (CD) and lipid binding studies were then performed on these analogs. Circular dichroism demonstrates enhanced helical content in the presence of lipid vesicles, particularly anionic lipid. The [Arg15,19,22,Lys29]RPTH (+6RPTH) analog requires higher concentrations of trifluoroethanol to attain enhanced helicity. The intrinsic tryptophan fluorescence of the peptides are blue shifted more in the presence of the anionic lipid dimyristoyl phosphatidylglycerol (DMPG) than with the zwitterionic lipid dimyristoyl phosphatidylcholine (DMPC). Effects of the peptides on the phase transition behavior of DMPC shows that +6RPTH has less effect on the lipid than does RPTH. This difference in lipid interaction is also exhibited with isothermal titration calorimetry, in which RPTH reacts exothermally with DMPG, while +6RPTH shows little or no heat change. The pH dependence of binding of the hydrophobic probe 1,1'-bis(4-anilino)-naphthalene-5,5'-trisulfonic acid, also shows a difference in exposure of hydrophobic sites between RPTH and +6RPTH. The +6RPTH has about a 5-fold greater affinity for receptor binding. We suggest that this enhanced activity is a consequence of the altered lipid interaction of +6RPTH, combined with increased conformational flexibility, particularly in the carboxyl-terminal region of the molecule.

Bryostatin 1 acts synergistically with interleukin-1 alpha to induce secretion of G-CSF and other cytokines from marrow stromal cells

The protein kinase C (PKC) activator bryostatin 1 (bryo) has substantial antileukemic and hematopoietic actions. Bryo promotes the in vitro growth of normal hematopoietic progenitors by inducing the release of growth factors from accessory cells. We have examined the effects of bryo on the expression and release of certain myeloid growth factors from fibroblastlike marrow stromal cells (MSC). Substantial release of granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF). or interleukin-6 (IL-6) following bryo treatment was seen only in MSC cultures contaminated with macrophages. Bryo alone was ineffective in inducing release of the cytokines from MSC cultures containing only fibroblastlike stromal cells. When MSC were treated with IL-1alpha, substantial quantities of the cytokines (G-CSF, GM-CSF,IL-6) were released. Bryo acted synergistically with IL-1 alpha to significantly increase cytokine release to- to nine-fold compared to IL-1alpha alone (p < 0.016). Neither Il-1alpha nor bryo, alone or in combination, induced release of stem cell factor (scf) from MSC. The synergistic interaction between IL-1alpha and bryo was dose- and schedule-dependent, requiring simultaneous application of IL-1alpha and bryo for optimum effect. Bryo alone induced no G-CSF mRNA accumulation but increased the level seen with IL-1alpha treatment by 50%. The synergistic interaction of bryo and IL-1alpha required PKC, since it was antagonized by agents which depleted or inhibited PKC but not by a protein kinase A antagonist. The increase in G-CSF mRNA was associated with a marked increase in mRNA stability. Bryostatin may promote the release of cytokines from several accessory cell populations, including MSC, to accomplish its in vivo hematopoietic effects.

Omission of Adjuvant Radiotherapy in Low-Risk Elderly Males with Breast Cancer

PURPOSE/OBJECTIVE(S)

Randomized clinical trials demonstrate that lumpectomy + hormone therapy (HT) without radiation therapy (RT) yields equivalent survival and acceptable local-regional outcomes in elderly women with early-stage, node-negative (T1-2N0) hormone-receptor positive (HR+) breast cancer. Whether these data apply to men with the same inclusion criteria remains unknown. We hypothesized that outcomes in males would be comparable to those seen in females, with RT not conferring an overall survival (OS) benefit over HT alone.

MATERIALS/METHODS

We conducted a retrospective matched-cohort study using the National Cancer Database for males ≥65 years with pathologic T1-2N0 (≤3 cm) HR+ breast cancer treated with breast conserving surgery with negative margins from 2004-2019. Patients who received chemotherapy, had nodal or distant metastases, or unknown follow-up were excluded. Adjuvant treatment was classified as HT alone, RT alone, or HT+RT. Due to limitations of survival analysis on retrospective data, male patients were matched with female patients to determine comparable outcomes based on age (± 3 years), Charlson Deyo comorbidity score, T-stage, and adjuvant treatment. Survival analysis was performed using Cox regression and Kaplan-Meier analysis. To adjust for confounding, inverse probability of treatment weighting (IPTW) was used.

RESULTS

A total of 523 patients met inclusion criteria, with 24.4% receiving HT, 16.3% receiving RT, and 59.2% receiving HT+RT. Median follow-up was 6.9 years (IQR: 5.0-9.4 years). Unadjusted 5-yr OS rates in the HT, RT, and HT+RT cohorts were 79.2% (95% CI 70.7-85.5%), 80.9% (95% CI 70.3-88.0%), and 93.3% (95% CI 89.7-95.7%), respectively. Adjusted 10-yr OS rates in the HT, RT, and HT+RT cohorts were 82.3% (95% CI 78.6-85.5%), 83.6% (95% CI 80.0-86.7%), and 92.8% (95% CI 90.1-94.8%), respectively. On unadjusted multivariable Cox regression analysis (MVA), relative to HT, receipt of HT+RT was associated with improvements in OS (HR: 0.603; 95% CI: 0.410-0.888; p = 0.01). RT alone was not associated with improved OS (HR: 1.116; 95% CI: 0.710-1.755; p = 0.633). On adjusted MVA, relative to HT, receipt of HT+RT was associated with improvements in OS (HR: 0.551; 95% CI: 0.370-0.820; p = 0.003). Again, RT alone was not associated with improved OS (HR: 0.991; 95% CI: 0.613-1.604; p = 0.972). Other factors associated with OS included age, Charlson Deyo score, T stage, and grade. Overall, in the matched women, the same trends were found as in the men, the best survival was in HT+RT, but no difference in OS between HT vs. RT.

CONCLUSION

Among men ≥65 years old with T1-2N0 HR+ breast cancer, RT alone did not confer an OS benefit over HT alone. Combined RT+HT did yield improvements in OS, though there are likely significant unmeasured confounders contributing to these outcomes in patients treated with the most aggressive approach. Our findings support that RT omission may be a reasonable option in elderly men with T1-2N0 HR+ breast cancer treated with lumpectomy + HT.