Medroxyprogesterone acetate antagonizes inhibitory effects of conjugated equine estrogens on coronary artery atherosclerosis

Although estrogen replacement therapy is associated with reduced risk of coronary heart disease and reduced extent of coronary artery atherosclerosis, the effects of combined (estrogen plus progestin) hormone-replacement therapy are uncertain. Some observational data indicate that users of combined hormone replacement consisting of continuously administered oral conjugated equine estrogens (CEE) and oral sequentially administered (7 to 14 days per month) medroxyprogesterone acetate (MPA) experience a reduction in risk similar to that of users of CEE alone. However, the effects of combined, continuously administered CEE plus MPA (a prescribing pattern that has gained favor) on the risk of coronary heart disease or atherosclerosis are not known. We studied the effects of CEE (monkey equivalent of 0.625 mg/d) and MPA (monkey equivalent of 2.5 mg/d), administered separately or in combination, on the extent of coronary artery atherosclerosis (average plaque size) in surgically postmenopausal cynomolgus monkeys fed atherogenic diets and treated with these hormones for 30 months. Treatment with CEE alone resulted in atherosclerosis extent that was reduced 72% relative to untreated (estrogen-deficient) controls (P < .004). Atherosclerosis extent in animals treated with CEE plus MPA or MPA alone did not differ from that of untreated controls. Although treatment had marked effects on plasma lipoprotein patterns, statistical adjustment for variation in plasma lipoproteins did not alter the between-group relationships in atherosclerotic plaque size, suggesting that these factors do not explain substantially the atheroprotective effect of estrogen or the MPA-associated antagonism. Although the mechanism(s) remains unclear, we conclude that oral CEE inhibits the initiation and progression of coronary artery atherosclerosis and that continuously administered oral MPA antagonizes this atheroprotective effect.

Estrogen and progesterone replacement therapy reduces low density lipoprotein accumulation in the coronary arteries of surgically postmenopausal cynomolgus monkeys

The effect of estrogen and progesterone replacement therapy on the initiating events in atherogenesis was studied in surgically postmenopausal cynomolgus monkeys. Monkeys were ovariectomized and divided randomly into two groups, one receiving 17 beta-estradiol and cyclic progesterone treatment (n = 9) and ovariectomized controls receiving no hormone replacement therapy (n = 8). The monkeys were fed a moderately atherogenic diet for 18 wk to accelerate the early pathogenic processes but not to be of sufficient duration to produce grossly visible atherosclerotic lesions. Sex hormone replacement therapy decreased the accumulation of LDL and products of LDL degradation in the coronary arteries by greater than 70% while having no significant effect on plasma lipid, lipoprotein, or apoprotein concentrations. Arterial intimal lesions were small with no difference between groups. The reduction in arterial LDL metabolism occurred very early in the pathogenesis of atherosclerosis and was independent of indices of endothelial cell injury, such as enhanced endothelial cell turnover or leukocyte adhesion to the endothelium. Results of this study suggest that one mechanism by which sex hormone treatment inhibits the initiation of atherosclerosis is a direct effect at the level of the arterial wall by suppressing the uptake and/or degradation of LDL.

Soy protein versus soy phytoestrogens in the prevention of diet-induced coronary artery atherosclerosis of male cynomolgus monkeys

Soy protein, long recognized as having cardiovascular benefits, is a rich source of phytoestrogens (isoflavones). To distinguish the relative contributions of the protein moiety versus the alcohol-extractable phytoestrogens for cardiovascular protection, we studied young male cynomolgus macaques fed a moderately atherogenic diet and randomly assigned to three groups. The groups differed only in the source of dietary protein, which was either casein/lactalbumin (casein, n = 27), soy protein with the phytoestrogens intact (soy+, n = 27), or soy protein with the phytoestrogens mostly extracted (soy-, n = 28). The diets were fed for 14 months. Animals fed soy+ had significantly lower total and LDL plus VLDL cholesterol concentrations compared with the other two groups. They soy+ animals had the highest HDL cholesterol concentrations, the casein group had the lowest, and the soy- group was intermediate. A subset was necropsied for atherosclerosis evaluations (n = 11 per group). Morphometric and angiochemical measures were done to quantify atherosclerosis. Coronary artery atherosclerotic lesions were smallest in the soy+ group (90% less coronary atherosclerosis than the casein group and 50% less than the soy- group), largest in the casein group, and intermediate in the soy- group. The effects of the diets on lesion size and arterial lipid measures of the peripheral arteries were similar to those in the coronary arteries, with greatest prevention of atherogenesis with soy+ and intermediate benefit with soy- relative to casein. We could not determine whether the beneficial effects seen in the soy- group relate to the protein itself or to the remaining traces of phytoestrogens. The beneficial effects of soy protein on atherosclerosis appear to be mediated primarily by the phytoestrogen component. Testicular weights were unaffected by the phytoestrogens.

The DEAH-box protein PRP22 is an ATPase that mediates ATP-dependent mRNA release from the spliceosome and unwinds RNA duplexes

Of the proteins required for pre-mRNA splicing, at least four, the DEAH-box proteins, are closely related due to the presence of a central 'RNA helicase-like' region, and extended homology through a large portion of the protein. A major unresolved question is the function of these proteins. Indirect evidence suggests that several of these proteins are catalysts for important structural rearrangements in the spliceosome. However, the mechanism for the proposed alterations is presently unknown. We present evidence that PRP22, a DEAH-box protein required for mRNA release from the spliceosome, unwinds RNA duplexes in a concentration- and ATP-dependent manner. This demonstrates that PRP22 can modify RNA structure directly. We also show that the PRP22-dependent release of mRNA from the spliceosome is an ATP-dependent process and that recombinant PRP22 is an ATPase. Non-hydrolyzable ATP analogs did not substitute for ATP in the RNA-unwinding reaction, suggesting that ATP hydrolysis is required for this reaction. Specific mutation of a putative ATP phosphate-binding motif in the recombinant protein eliminated the ATPase and RNA-unwinding capacity. Significantly, these data suggest that the DEAH-box proteins act directly on RNA substrates within the spliceosome.

Predicting sentinel and residual lymph node basin disease after sentinel lymph node biopsy for melanoma

BACKGROUND

The selection of patients for sentinel lymph node biopsy (SNB) and selective lymphadenectomy for histologically positive sentinel lymph nodes (SLND) are areas of debate. The authors of the current study attempted to identify predictors of metastases to the sentinel and residual nonsentinel lymph nodes in patients with melanoma.

METHODS

The Indiana University Interdisciplinary Melanoma Program computerized database was queried to identify all patients who underwent SNB for clinically localized cutaneous melanoma. Demographic, surgical, and histopathologic data were recorded. Univariate and multivariate logistic regression analyses were performed to identify associations with SNB and nonsentinel lymph node positivity. Classification tree and logistic procedures were performed to identify the ideal tumor thickness cutpoint at which to perform SNB.

RESULTS

Two hundred seventy-five SNB procedures were performed to stage 348 regional lymph node basins for occult metastases from melanoma. Of the 275 melanomas, 54 (19.6%) had a positive SNB, as did 58 of 348 basins (16.7%). Classification and logistic regression analysis identified a Breslow depth of 1.25 mm to be the most significant cutpoint for SNB positivity (odds ratio 8. 8:1; P = 0.0001). By multivariate analyses, a Breslow thickness cutpoint >/= 1.25 mm (P = 0.0002), ulceration (P = 0.005), and high mitotic index (> 5 mitoses/high-power field; P = 0.04) were significant predictors of SNB results. SLND was performed in 53 SNB positive patients, 15 of whom (28.3%) had at least 1 additional positive lymph node. SLND positivity was noted across a wide range of primary tumor characteristics and was associated significantly with multiple positive SN, but not with any other variable. SNB result correlated significantly with disease free and overall survival.

CONCLUSIONS

Patients with a Breslow tumor thickness >/= 1. 25 mm, ulceration, and high mitotic index are most likely to have positive SNB results. SLND is recommended for all patients after positive SNB because it is difficult to identify patients with residual lymph node disease.

A hydroxyl radical-like species oxidizes cynomolgus monkey artery wall proteins in early diabetic vascular disease

Recent evidence argues strongly that the marked increase in risk for atherosclerotic heart disease seen in diabetics cannot be explained by a generalized increase in oxidative stress. Here, we used streptozotocin to induce hyperglycemia in cynomolgus monkeys for 6 months and tested whether high glucose levels promote localized oxidative damage to artery wall proteins. We focused on three potential agents of oxidative damage: hydroxyl radical, tyrosyl radical, and reactive nitrogen species. To determine which pathways operate in vivo, we quantified four stable end products of these reactants -- ortho-tyrosine, meta-tyrosine, o,o'-dityrosine, and 3-nitrotyrosine -- in aortic proteins. Levels of ortho-tyrosine, meta-tyrosine, and o,o'-dityrosine, but not of 3-nitrotyrosine, were significantly higher in aortic tissue of hyperglycemic animals. Of the oxidative agents we tested, only hydroxyl radical mimicked this pattern of oxidized amino acids. Moreover, tissue levels of ortho-tyrosine and meta-tyrosine correlated strongly with serum levels of glycated hemoglobin, a measure of glycemic control. We conclude that short-term hyperglycemia in primates promotes oxidation of artery wall proteins by a species that resembles hydroxyl radical. Our observations suggest that glycoxidation reactions in the arterial microenvironment contribute to early diabetic vascular disease, raising the possibility that antioxidant therapies might interrupt this process.

Dietary soy protein and estrogen replacement therapy improve cardiovascular risk factors and decrease aortic cholesteryl ester content in ovariectomized cynomolgus monkeys

Estrogen replacement therapy (ERT) decreases the progression of coronary artery atherosclerosis in monkeys. Dietary soy protein also retards the progression of atherosclerosis relative to animal proteins such as casein. Soy protein contains weakly estrogenic compounds called isoflavones or phytoestrogens that may be responsible for the cardioprotective effects. This study was designed as a 2 x 2 factorial to determine the magnitude of soy protein's effects on cardiovascular risk factors relative to casein and lactalbumin, with or without estradiol treatment. Ovariectomized female monkeys were randomized to four treatment groups based on past dietary cholesterol consumption, their origin, and past reproductive history, and studied for 7 months. The animals were divided into (1) a group fed casein and lactalbumin as the protein source (n = 14), (2) a group fed casein and lactalbumin as the protein source plus 17 beta-estradiol (E2) (n = 13), (3) a group fed soybean protein isolate as the protein source (n = 11), and (4) a group fed soybean protein isolate as the protein source plus E2 (n = 10). Soy protein compared with casein consumption resulted in a significant improvement in plasma lipid and lipoprotein concentrations, a significant improvement in insulin sensitivity and glucose effectiveness as determined by minimal-model analyses, and a decrease in arterial lipid peroxidation. E2-treated monkeys had a significant reduction in fasting insulin levels and insulin to glucose ratios, total body weight, and amounts of abdominal fat, and had smaller low-density lipoprotein (LDL) particles. In addition, E2 treatment resulted in a significant reduction (P = .001) in aortic cholesteryl ester content. A similar trend (P = .14) was found for soy protein compared with casein. There also was a significant interaction (P = .02) with soy and E2, such that animals consuming soy protein +E2 had the least arterial cholesteryl ester content. These results suggest that both ERT and dietary soybean protein have beneficial effects on cardiovascular risk factors. Interestingly, the two treatments affected different risk factors and together resulted in the greatest reduction in arterial cholesterol content. Further studies are needed to determine the active component of the soy protein and to assess its long-term effects on the cardiovascular system and other organ systems (such as the bones and reproductive system).

Prospective study of fluorodeoxyglucose-positron emission tomography imaging of lymph node basins in melanoma patients undergoing sentinel node biopsy

PURPOSE

To prospectively compare positron emission tomography (PET) imaging of regional lymph node basins to sentinel node biopsy (SNB) in patients with American Joint Committee on Cancer (AJCC) stage I, II, and III melanoma localized to the skin.

METHODS

Patients with cutaneous melanoma with Breslow's depth greater than 1 mm (AJCC T2-4N0M0) or localized regional cutaneous recurrence (TxN2bM0) underwent whole-body imaging of glucose metabolism with fluorodeoxyglucose (FDG) PET followed by SNB. PET scans were interpreted in a blinded fashion and compared with histologic analyses of SNB specimens and clinical follow-up examination. Nodal tumor volumes were estimated.

RESULTS

Eighty-nine lymph node basins were evaluated by FDG-PET and SNB in 70 assessable patients. Eighteen patients (25.7%) had lymph node metastases at the time of FDG-PET imaging: 17 proved by SNB (24.3%) and one by follow-up examination (1.4%). Median tumor volume in positive sentinel node basins was 4.3 mm3 (range, 0.07 to 523 mm3). Sensitivity of SNB for detection of occult regional lymph node metastases was 94.4%, specificity was 100%, positive predictive value (PPV) was 100%, and negative predictive value (NPV) was 98.6%. Sensitivity of FDG-PET was 16.7%, specificity was 95.8%, PPV was 50%, and NPV was 81.9%. At a median follow-up duration of 16.6 months, seven patients (10%) developed recurrent disease. PET predicted one recurrence (14.3%) in a node basin missed by SNB.

CONCLUSION

FDG-PET is an insensitive indicator of occult regional lymph node metastases in patients with melanoma because of the minute tumor volumes in this population. FDG-PET does not have a primary role for staging regional nodes in patients with clinically localized melanoma.

Intact dietary soy protein, but not adding an isoflavone-rich soy extract to casein, improves plasma lipids in ovariectomized cynomolgus monkeys

The dietary consumption of soy protein has been linked to a reduction in coronary heart disease and improvements in a number of related risk factors. Recent investigations have focused on isoflavone components of soy protein. The purpose of this study was to examine plasma lipids and lipoproteins, particularly LDL, with the intake of intact soy protein or casein-lactalbumin diets with and without a semipurified extract of soy, rich in isoflavones. Sixty ovariectomized cynomolgus monkeys were assigned to one of three groups fed diets containing the following: 1) casein-lactalbumin as the protein source (CAS; n = 20); 2) CAS plus a semipurified extract of soy, rich in isoflavones (ISO; n = 20); or 3) intact soy protein (SOY; n = 20) for 12 wk. Lipoproteins were fractionated by combined ultracentrifugation and HPLC. Isolated LDL particles were further subfractionated by dividing the LDL peak into three fractions for compositional analyses. The SOY group had significantly lower plasma total cholesterol, VLDL plus IDL cholesterol and LDL cholesterol, and significantly less HDL cholesterol than the CAS group. LDL particles from the SOY group had a significantly less cholesteryl ester than the CAS group. The semipurified extract of soy, rich in isoflavones, added to casein-lactalbumin protein did not have the same effects as intact soy protein on plasma lipids and lipoproteins. Other components of soy protein, either alone or in combination with isoflavones, may be involved in the effects seen in this study.

Cervical sentinel lymph node biopsy for melanomas of the head and neck and upper thorax

OBJECTIVE

To describe a clinical experience with sentinel lymph node biopsy (SLNB) of head and neck nodal basins for clinical stage I melanomas draining to these areas.

DESIGN

Consecutive clinical case series with a mean follow-up of 10.7 months.

SETTING

University tertiary care referral medical center.

PATIENTS

Seventy patients with clinical stage I cutaneous melanoma who underwent SLNB of cervical and/or parotid lymph node basins.

INTERVENTIONS

Patients underwent same-day preoperative technetium Tc 99m lymphoscintigraphy followed by SLNB using gamma probe and blue dye (66 patients) and blue dye alone (4 patients). Patients with histological evidence of tumor (here in after "positive") according to SLNB results underwent modified cervical completion lymph node dissection, including parotidectomy, as appropriate. Patients without histological evidence of tumor (hereinafter "negative") according to SLNB results were followed up clinically without undergoing completion lymph node dissection.

MAIN OUTCOME MEASURES

The rates of SLNB success, SLNB positivity, completion lymph node dissection positivity, complications, and SLNB false-negative results were determined by clinical follow-up.

RESULTS

Locations of melanomas in the 70 patients were the face (n = 20), neck (n = 14), ear (n = 9), scalp (n = 9), and upper thorax (n = 18). Locations of basins that underwent biopsy (n = 104) were in the cervical (n = 68), parotid (n = 19), and axillary (n = 17) regions. The mean Breslow thickness was 2.1 mm (range, 0.4-12.0 mm). Sentinel lymph node biopsy was successful in 103 basins (99%). The mean number of sentinel lymph nodes per basin was 2.5 (range, 1.0-8.0). Positive sentinel lymph nodes were found in 12 patients (17%) and 15 basins (14%). Sentinel lymph node biopsy results correlated with the American Joint Committee on Cancer tumor stage (P = .05) and a Breslow thickness of 1.23 mm or greater (P = .03). Additional tumor-containing nodes were noted in 5 (42%) of the 12 patients who underwent completion lymph node dissection, and these results correlated with the presence of multiple positive sentinel lymph nodes (P = .01). There were complications in 3 patients (4%) (seromas in 2 patients and temporary spinal accessory nerve paresis in 1 patient). One nodal recurrence in a basin that was negative according to SLNB results (SLNB with blue dye only) was noted (false-negative rate, 2%). The results of SLNB were accurate in 69 patients (99%).

CONCLUSIONS

Sentinel lymph node biopsy using lymphoscintigraphy and blue dye to manage cutaneous melanomas draining to the head and neck nodal areas is reliable and safe. Sentinel lymph node biopsy results correlated with a Breslow thickness of 1.23 mm or greater and the American Joint Committee on Cancer tumor stage. Completion lymph node dissection is recommended after determining positive SLNB results.

The DEAH-box splicing factor Prp16 unwinds RNA duplexes in vitro

BACKGROUND

During pre-mRNA splicing, dynamic rearrangement of RNA secondary structure within the spliceosome is crucial for intron recognition and formation of the catalytic core. Splicing factors belonging to the DExD/DExH-box family of RNA-dependent ATPases are thought to have a central role in directing these rearrangements by unwinding RNA helices. Proof of this hypothesis has, however, been conspicuously lacking.

RESULTS

Prp16 is a DEAH-box protein that functions in the second step of splicing in vitro. Using various RNA duplexes as substrate, we have shown that Prp16 has an ATP-dependent RNA unwinding activity. This activity is independent of sequence in either the single-stranded or duplexed regions of the RNA substrate. A mutation (prp16-1) near the ATP-binding motif of Prp16 inhibits both the RNA-dependent ATPase activity and the ATP-dependent RNA unwinding activity.

CONCLUSIONS

Our findings provide strong biochemical evidence that Prp16 can disrupt a duplexed RNA structure on the spliceosome. Because the purified protein lacks sequence specificity in unwinding RNA duplexes, targeting of the unwinding activity of Prp16 in the spliceosome is likely to be determined by other interacting protein factors. The demonstration of unwinding activity will also help our understanding of how the fidelity of branchpoint recognition is controlled by Prp16.

FDG-PET sensitivity for melanoma lymph node metastases is dependent on tumor volume

BACKGROUND AND OBJECTIVES

The purpose of this study is to determine the tumor volume threshold for successful positron emission tomography (PET) imaging of melanoma nodal metastases.

METHODS

Review of a clinical series of patients who had FDG-PET imaging of regional lymph node basins followed by lymphadenectomy. Lymph node tumor volumes were calculated from direct measurements of metastatic nodule(s) in formalin fixed specimens. PET scan interpretations were correlated with histology to determine sensitivity. Sensitivity was correlated with the aggregate lymph node tumor volume in the nodal basin and with AJCC stage group.

RESULTS

Forty-five patients with 49 pathologically positive regional nodal basins comprised the study group. Median total basin tumor volume was 28.3 mm(3)(range 0.004-22,879 mm(3)). FDG-PET sensitivity for detection of all tumor volumes was 0.49. The observed 90% sensitivity threshold for detection of nodal metastases was > or = 78 mm(3). PET sensitivity was 0.14 for detection of tumor volumes < 78 mm(3). PET sensitivity differed by prescan AJCC stage: I-0.0; II-0.24; III-0.81; IV-1.0 (P < 0.001).

CONCLUSIONS

FDG-PET reliably detects lymph node tumor deposits greater than approximately 80 mm(3) volume, but sensitivity falls rapidly below this. This amount of tumor is most likely to occur in patients with AJCC stage III or IV disease.

1-p-chlorophenyl-4,4-dimethyl-5-diethylamino-1-penten-3-one hydrobromide, a sulfhydryl-specific compound which reacts irreversibly with protein thiols but reversibly with small molecular weight thiols

1-p-Chlorophenyl-4,4-dimethyl-5-diethylamino-1-penten-3-one hydrobromide (CDDP) has been shown to react selectively with small molecular weight and protein thiols. The reaction of this compound with thiols can be monitored directly owing to the large decrease (approximately 21,000 M-1 cm-1 at 310 nm) in extinction coefficient subsequent to thiol addition. CDDP reacted stoichiometrically with large molecular weight (greater than 11,000) protein thiols. However, with small molecular weight thiols (less than 500) the reaction was less than stoichiometric, indicating a significant degree of back-reaction. The forward and reverse rate constants have been estimated. The fact that the reaction is reversible enables CDDP to be used for the direct monitoring of the oxidation of small molecular weight thiols.

Lymph node tumor volumes in patients undergoing sentinel lymph node biopsy for cutaneous melanoma

BACKGROUND

Regional lymph node tumor volumes in patients undergoing sentinel lymph node (SN) biopsy (SNB) for treatment of cutaneous melanoma have not been described. The objectives of this study were to describe the lymph node tumor volumes typically seen in this population and to correlate tumor volumes with tumor thickness and positive SN characteristics.

METHODS

Review of a consecutive series of patients with clinically localized cutaneous melanoma who underwent SNB of nonpalpable regional lymph node basins followed by complete lymphadenectomy (LND) was performed. Multiple lymph node sections from positive SNs and nonsentinel nodes (NSNs) in LND specimens were examined microscopically. Individual tumor deposit diameters were measured using an ocular micrometer. Aggregate tumor volumes were calculated for SN and LND specimens. Tumor volumes and SN and LND positivity rates were correlated with tumor thickness, the number of positive SNs, and the presence of multiple SN tumor deposits.

RESULTS

SNB procedures were performed for 149 melanomas in 189 regional nodal basins. The mean tumor depth was 2.48 mm. The mean number of SNs/basin was 2.1. Thirty-two of 149 SNB procedures (21.5%) revealed a total of 34 nodal basins with at least one positive SN. The median tumor volume in positive SNs was 4.7 mm3 (range, 0.1-3618 mm3; mean, 209 mm3). The median aggregate tumor volume in positive LND specimens was 4.9 mm3 (range, 0.1-3618 mm3; mean, 224 mm3). Six basins (17.6%) contained at least one positive NSN. The regional node aggregate tumor volume correlated weakly with tumor thickness (Pearson's correlation coefficient = .302, P = .0934). NSN positivity was not predicted by tumor thickness, American Joint Committee on Cancer tumor stage, number of positive SNs, or number of metastatic deposits within SNs.

CONCLUSIONS

Most melanoma-positive SNs contain minute tumor volumes. Tumor thickness and patterns of SN metastases may not be predictive of tumor burden or the presence of positive NSNs.

Consumption of soy protein reduces cholesterol absorption compared to casein protein alone or supplemented with an isoflavone extract or conjugated equine estrogen in ovariectomized cynomolgus monkeys

Dietary intake of soy protein is associated with reductions in plasma cholesterol. Isoflavones are thought to be active components of soy and responsible for the beneficial effects because of their structural similarities to estrogen. The purposes of this study were to determine if i) soy protein or a semipurified soy extract, rich in isoflavones, is responsible for improving the lipid profile and ii) altered intestinal cholesterol metabolism is one mechanism for hypocholesterolemic effects. Ovariectomized adult female cynomolgus monkeys (40) were assigned to groups fed diets containing i) casein-lactalbumin (CAS) ii) intact soy protein (SOY), iii) CAS plus an isoflavone-rich semipurified soy extract similar in isoflavone content as SOY (ISO) or iv) CAS plus conjugated equine estrogen (CEE) for 20 wk. Cholesterol absorption was determined using the fecal isotope ratio method. Bile acid excretion was measured using the 3alpha-hydroxysteroid dehydrogenase assay. The SOY group had significantly lower total- and VLDL + LDL-cholesterol compared to the other three groups and significantly higher HDL-cholesterol compared to the CAS and CEE groups. Cholesterol absorption was significantly lower in the SOY group compared to the other groups, but bile acid excretion was not significantly affected. The hypocholesterolemic effect of soy protein appears to be mediated in part by decreased cholesterol absorption. The semipurified soy extract, rich in isoflavones, added to casein protein did not have lipid-lowering effects. Other components of soy such as saponins, phytic acid or the amino acid composition may be involved in the hypocholesterolemic effects seen in this study.

Initial assessment of positron emission tomography for detection of nonpalpable regional lymphatic metastases in melanoma

BACKGROUND

The purpose of this pilot study is to determine the feasibility of positron emission tomography with fluorodeoxyglucose (FDG-PET) for detection of nonpalpable regional lymph node metastases in patients with melanoma.

METHODS

Adult patients with histologically proven cutaneous melanoma planned to undergo surgical lymphadenectomy for treatment of nonpalpable subclinical or residual metastatic melanoma in regional lymph node basin(s) participated. Each patient underwent attenuation-corrected PET imaging of the regional lymph node basin(s) with F18 fluorodeoxyglucose (FDG) followed by complete surgical lymphadenectomy. FDG-PET scans were interpreted prospectively by an experienced nuclear medicine physician. FDG-PET scan interpretations and histologic results were then correlated.

RESULTS

Eleven patients underwent 12 FDG-PET scans followed by 12 operations to clear 14 regional lymph node basins. FDG-PET correctly predicted the presence of metastatic melanoma in seven of seven surgical specimens. FDG-PET scans correctly predicted the absence of disease in seven of seven histologically negative node basins. Sensitivity was 1.0; specificity was 1.0.

CONCLUSIONS

This study suggests that increased fluorodeoxyglucose uptake in palpably unremarkable regional lymph node basins in patients with melanoma is highly suggestive of metastatic disease.

Current therapy of cutaneous melanoma

Melanoma is a growing public health problem. Optimal care of the melanoma patient is multidisciplinary, but plastic surgeons and other surgical specialties play a central role in the management of these patients. Although surgery remains the mainstay of therapy for melanoma, several recent clinical studies have helped to clarify the biology of the disease and have changed the patterns of care for patients with melanoma. The advent of lymphatic mapping for interrogation of regional lymph nodes and interferon as the first effective postsurgical adjuvant therapy have had a major impact on the care of melanoma in the United States and elsewhere. This article will review the current clinical approach and therapy for cutaneous melanoma. The diagnosis, prognostic variables, staging evaluation, current surgical and medical treatment, and follow-up guidelines for patients with all stages of melanoma are reviewed. Recent studies, controversies, and directions of future investigational therapies will be discussed.

A study of caloric restriction and cardiovascular aging in cynomolgus monkeys (Macaca fascicularis): a potential model for aging research

Caloric restriction has been demonstrated to retard aging processes and extend maximal life span in rodents, and is currently being evaluated in several nonhuman primate trials. We initiated a study in 32 adult cynomolgus monkeys to evaluate the effect of caloric restriction on parameters contributing to atherosclerosis extent. Following pretrial determinations, at which time a baseline measure of ad libitum (ad lib) dietary intake was assessed, animals were randomized to an ad lib fed group (control) or a caloric restriction group (30% reduction from baseline intake). The animals are being evaluated for glycated proteins, insulin, glucose, insulin sensitivity measures, and specific measures of body fat composition by CT scans (e.g., intra-abdominal fat) over specified intervals. The results from the first year of observation demonstrate a significant diet effect on body weight, and specifically intra-abdominal fat. Further, insulin sensitivity has been significantly increased after 1 year of caloric restriction compared to the ad lib fed group. These studies indicate that caloric restriction has a marked effect on a pathologic fat depot, and this change is associated significantly with an improvement in peripheral tissue insulin sensitivity.

Sentinel lymph node biopsy for melanoma: experience with 234 consecutive procedures

Sentinel lymph node biopsy is increasingly used to identify occult metastases in regional lymph nodes of patients with melanoma. Selection of patients for sentinel lymph node biopsy and subsequent lymphadenectomy is an area of debate. The purpose of this study was to describe a large clinical series of these biopsies for cutaneous melanoma and to identify patients most likely to gain useful clinical information from sentinel lymph node biopsy. The Indiana University Melanoma Program computerized database was queried to identify all patients who underwent this procedure for clinically localized cutaneous melanoma. It was performed using preoperative technetium Tc 99m lymphoscintigraphy and isosulfan blue dye. Pertinent demographic, surgical, and histopathologic data were recorded. Univariate and multivariate logistic regression and classification table analyses were performed to identify clinical variables associated with sentinel node and nonsentinel node positivity. In total, 234 biopsy procedures were performed to stage 291 nonpalpable regional lymph node basins. Mean Breslow's thickness was 2.30 mm (2.08 mm for negative sentinel lymph node biopsy, 3.18 mm for positive). The mean number of sentinel nodes removed was 2.17 nodes per basin (range, 1 to 8). Forty-seven of 234 melanomas (20.1 percent) and 50 of 291 basins (17.2 percent) had a positive biopsy. Positivity correlated with AJCC tumor stage: T1, 3.6 percent; T2, 8.1 percent; T3, 27.4 percent; T4, 44 percent. By univariate logistic regression, Breslow's thickness (p = 0.003, continuous variable), ulceration (p = 0.003), mitotic index > or = 6 mitoses per high power field (p = 0.008), and Clark's level (p = 0.04) were significantly associated with sentinel lymph node biopsy result. By multivariate analysis, only Breslow's thickness (p = 0.02), tumor ulceration (p = 0.02), and mitotic index (p = 0.02) were significant predictors of biopsy positivity. Classification table analysis showed the Breslow cutpoint of 1.2 mm to be the most efficient cutpoint for sentinel lymph node biopsy result (p = 0.0004). Completion lymphadenectomy was performed in 46 sentinel node-positive patients; 12 (26.1 percent) had at least one additional positive nonsentinel node. Nonsentinel node positivity was marginally associated with the presence of multiple positive sentinel nodes (p = 0.07). At mean follow-up of 13.8 months, four of 241 sentinel node-negative basins demonstrated same-basin recurrence (1.7 percent). Sentinel lymph node biopsy is highly reliable in experienced hands but is a low-yield procedure in most thin melanomas. Patients with melanomas thicker than 1.2 mm or with ulcerated or high mitotic index lesions are most likely to have occult lymph node metastases by sentinel lymph node biopsy. Completion therapeutic lymphadenectomy is recommended after positive biopsy because it is difficult to predict the presence of positive nonsentinel nodes.

Naturally occurring and experimental diabetes in cynomolgus monkeys: a comparison of carbohydrate and lipid metabolism and islet pathology

Diabetes is a major health problem of increasing incidence in the United States. Diabetes research has been limited by lack of availability of good animal models, particularly for the study of comorbidities associated with diabetes. We investigated the use of cynomolgus monkeys as an animal model of both type 1 and type 2 diabetes and compared these naturally occurring diseases with streptozotocin-induced diabetes. Both type 1 diabetics and streptozotocin-induced diabetics present with sudden onset of hyperglycemia and are ketosis prone without exogenous insulin. Type 2 diabetics can have a very long period of moderate hyperglycemia and hypertriglyceridemia and only require exogenous insulin therapy if pancreatic islet reserves are depleted. Type 2 diabetes is preceded by a relatively long period of insulin resistance that is associated with obesity and dyslipidemia. As insulin resistance progresses, islet size and insulin content increases initially. However, with sustained periods of insulin resistance, islet amyloid polypeptide (IAPP) is deposited in islets and can replace normal islet architecture, resulting in an insulin-deficient state. Appearance of IAPP also occurs in human type 2 diabetics but not in conventional rodent models. Unlike type 2 diabetes, neither type 1 nor streptozotocin-induced diabetes is associated with IAPP. Rather, islets can appear normal histologically, but have decreased insulin secretion and immunostaining. Further, the amount of insulin present in the islet is correlated with plasma insulin levels following glucose challenge. Studies are ongoing to determine the pathogenic changes associated with the progression of diabetes and to find novel drug treatments for diabetics.

A comparison of tibolone and conjugated equine estrogens effects on coronary artery atherosclerosis and bone density of postmenopausal monkeys

This study compared the effects of tibolone, a tissue-specific compound for the treatment of climacteric symptoms and the prevention of osteoporosis, with those of conjugated equine estrogens (CEE) with and without medroxyprogesterone (MPA) on bone mineral density and coronary atherosclerosis (CAA) of postmenopausal cynomolgus monkeys. The groups were tibolone [two doses were used, 0.05 mg/kg (LoTib) and 0.2 mg/kg (HiTib)], CEE (0.042 mg/kg), CEE (0.042 mg/kg) plus MPA (0.167 mg/kg given continuously), and a control group given no treatment for 2 yr. Compared with no treatment, bone mineral density was higher by 6.3% (P = 0.0004) in the LoTib group and by 9.5% (P = 0.02) in the HiTib group compared with 4.3% (P = 0.12) for CEE and 4.5% (P = 0.10) for CEE+MPA. Plasma high density lipoprotein cholesterol was reduced by 49% with HiTib and by 34% with LoTib. There were no differences in CAA between control and HiTib (P = 0.60) or LoTib (P = 0.58). CEE and CEE+MPA both reduced CAA by about 62% (CEE vs. control, P = 0.02; CEE+MPA vs. control, P = 0.01). Despite adverse effects of tibolone on plasma lipoprotein concentrations, there was no increase in CAA, suggesting that tibolone is a cardiovascular-safe treatment for climacteric symptoms and the prevention of osteoporosis.

Assessment of Proplast-Teflon disc replacements

This retrospective study reports the findings in the follow-up of 31 temporomandibular joints in which Proplast-Teflon (Vitek Inc, Houston, TX) replacements were used. Among the problems noted were pain, malocclusion, restricted opening, and degenerative changes in the condyle and fossa.

Tamoxifen inhibits arterial accumulation of LDL degradation products and progression of coronary artery atherosclerosis in monkeys

Estrogen replacement therapy reduces the risk of coronary heart disease in postmenopausal women and inhibits progression of coronary artery atherosclerosis in monkeys. Tamoxifen is a nonsteroidal compound with mixed estrogen agonist and antagonist properties. Its antagonist activity is useful in chemotherapy of breast cancer and may have protective effects on plasma lipid concentrations, but its effects on atherogenesis have not been defined. The goal of this study was to examine the effect of tamoxifen on plasma lipids, arterial and hepatic LDL metabolism, and progression of coronary artery atherosclerosis in surgically postmenopausal female monkeys. Thirty-five monkeys were fed an atherogenic diet containing 1.3 mg.kg-1.d-1 tamoxifen (equivalent to the usual dose of 20 mg/d given to women). Thirty-one monkeys were fed the same atherogenic diet with no tamoxifen. Ten monkeys from each treatment group were fed the test diets for 12 weeks to examine the short-term effects of tamoxifen on arterial LDL metabolism. The rest of the monkeys were fed the test diets for 3 years to study the long-term effects of tamoxifen on development of atherosclerosis. In the short term, tamoxifen inhibited the rate of arterial accumulation of LDL degradation products overall (P = .03) and decreased hepatic cholesterol content (P = .003). In the long term, tamoxifen increased plasma concentrations of triglycerides (0.60 +/- 0.67 versus 0.23 +/- 0.02 mmol/L, P = .001) and reduced average LDL molecular weight (5.3 +/- 0.2 versus 4.8 +/- 0.1 g/mumol, P = 0.004) but had no effects on plasma total, LDL, or HDL cholesterol concentrations. Coronary artery atherosclerosis (intimal area, mean +/- SEM) was 0.25 +/- 0.06 mm2 in control monkeys and 0.12 +/- 0.03 mm2 in tamoxifen-treated monkeys (P = .057). We conclude that tamoxifen has antiatherogenic effects that may be modulated in part through direct effects on arterial LDL metabolism.

Whole-exome sequencing is a valuable diagnostic tool for inherited peripheral neuropathies: Outcomes from a cohort of 50 families

The inherited peripheral neuropathies (IPNs) are characterized by marked clinical and genetic heterogeneity and include relatively frequent presentations such as Charcot-Marie-Tooth disease and hereditary motor neuropathy, as well as more rare conditions where peripheral neuropathy is associated with additional features. There are over 250 genes known to cause IPN-related disorders but it is estimated that in approximately 50% of affected individuals a molecular diagnosis is not achieved. In this study, we examine the diagnostic utility of whole-exome sequencing (WES) in a cohort of 50 families with 1 or more affected individuals with a molecularly undiagnosed IPN with or without additional features. Pathogenic or likely pathogenic variants in genes known to cause IPN were identified in 24% (12/50) of the families. A further 22% (11/50) of families carried sequence variants in IPN genes in which the significance remains unclear. An additional 12% (6/50) of families had variants in novel IPN candidate genes, 3 of which have been published thus far as novel discoveries (KIF1A, TBCK, and MCM3AP). This study highlights the use of WES in the molecular diagnostic approach of highly heterogeneous disorders, such as IPNs, places it in context of other published neuropathy cohorts, while further highlighting associated benefits for discovery.

Sonchus yellow net rhabdovirus nuclear viroplasms contain polymerase-associated proteins

We have initiated a study of the cytopathology of nucleorhabdoviruses by analyzing the subcellular localization of sonchus yellow net virus (SYNV) genomic and antigenomic RNAs and the encoded polymerase proteins. In situ hybridizations demonstrated that the minus-strand genomic RNA sequences are restricted to the nuclei of infected cells, while the complementary plus-strand antigenomic RNA sequences are present in both the nuclei and the cytoplasm. Immunofluorescence and immunogold labeling experiments also revealed that the nucleocapsid (N) protein and phosphoprotein (M2) are primarily localized to discrete regions within the nuclei and in virus particles that accumulate in perinuclear spaces. The N protein antiserum specifically labeled the nuclear viroplasms, whereas the M2 antiserum was more generally distributed throughout the nuclei. Antibody detection also indicated that the polymerase (L) protein is present in small amounts in the viroplasm. When the N and M2 proteins were expressed individually from the heterologous potato virus X (PVX) vector, both proteins preferentially accumulated in the nuclei. In addition, viroplasm-like inclusions formed in the nuclei of cells infected with the PVX vector containing the N gene. Fusions of the carboxy terminus of beta-glucuronidase to N and M2 resulted in staining of the nuclei of infected cells following expression from the PVX vector. Deletion analyses suggested that multiple regions of the N protein contain signals that are important for nuclear localization.