Barriers and facilitators of hepatitis C screening among people who inject drugs: a multi-city, mixed-methods study

Background

People who inject drugs (PWID) are at high risk of contracting and transmitting and hepatitis C virus (HCV). While accurate screening tests and effective treatment are increasingly available, prior research indicates that many PWID are unaware of their HCV status.

Methods

We examined characteristics associated with HCV screening among 553 PWID utilizing a free, multi-site syringe exchange program (SEP) in 7 cities throughout Wisconsin. All participants completed an 88-item, computerized survey assessing past experiences with HCV testing, HCV transmission risk behaviors, and drug use patterns. A subset of 362 clients responded to a series of open-ended questions eliciting their perceptions of barriers and facilitators to screening for HCV. Transcripts of these responses were analyzed qualitatively using thematic analysis.

Results

Most respondents (88%) reported receiving a HCV test in the past, and most of these (74%) were tested during the preceding 12 months. Despite the availability of free HCV screening at the SEP, fewer than 20% of respondents had ever received a test at a syringe exchange site. Clients were more likely to receive HCV screening in the past year if they had a primary care provider, higher educational attainment, lived in a large metropolitan area, and a prior history of opioid overdose. Themes identified through qualitative analysis suggested important roles of access to medical care and prevention services, and nonjudgmental providers.

Conclusions

Our results suggest that drug-injecting individuals who reside in non-urban settings, who have poor access to primary care, or who have less education may encounter significant barriers to routine HCV screening. Expanded access to primary health care and prevention services, especially in non-urban areas, could address an unmet need for individuals at high risk for HCV.

Barriers and facilitators of universal HIV screening among internal medicine residents

BACKGROUND

Adoption of universal HIV screening has been low despite national recommendations.

OBJECTIVE

To describe the barriers and facilitators to adoption of universal HIV screening in a low-prevalence setting.

DESIGN

Qualitative, thematic analysis of focus group discussions among internal medicine residents who introduced universal HIV screening into their primary care practice in Madison, Wisconsin.

APPROACH

Deductive and inductive codes constructed a hybridized thematic analysis model. Deductive codes stemmed from a knowledge-attitude-behavior framework for physician nonadherence to guidelines. Inductive codes emerged from the focus group discussions and were embedded into broader deductive codes to provide an HIV-specific model.

KEY RESULTS

Residents were knowledgeable and had positive attitudes toward recommendations for universal HIV screening. Residents felt the majority of their patients were receptive to HIV screening, especially when introduced with normalizing techniques and reference to an expert authority such as the Centers for Disease Control and Prevention (CDC). They still perceived patient discussions as challenging due to stigma surrounding HIV and patients' perceptions of being at low risk. Residents employed individualized electronic medical record cues as a memory aid to discuss the issue.

CONCLUSION

This qualitative study of internal medicine residents training in an area with low HIV prevalence suggests that stigma and patient perception of being at low risk are barriers that should be addressed to effectively integrate universal HIV screening into primary care.

Identifying transcribed sequences in arrayed bacteriophage or cosmid libraries

This unit describes methods for identifying bacteriophage or cosmid clones that contain sequences present in the mRNA of a cell line or tissue. In the , a radiolabeled cDNA probe is synthesized by reverse transcription of poly(A)+ RNA isolated from the cell line or tissue of interest. The probe is incubated with DNA-cellulose to remove highly repetitive sequences before it is used for hybridization analysis of filters from a phage or cosmid genomic library. After identification of positive clones from the library screen, the same probe can be used to screen Southern blots of restriction enzyme-digested DNA from the positive clones. Support protocols describe preparation and testing of DNA-cellulose.

Proopiomelanocortin heterozygous and homozygous null mutant mice develop pituitary adenomas

Mice lacking all pro-opiomelanocortin (POMC)-derived peptides have been created by gene targeting of the POMC locus in embryonic stem cells. Phenotypes of the POMC null homozygous mutants include obesity, pigmentation defects, and adrenal insufficiency. Here, we report that both POMC null homozygous and heterozygous mutants also develop pituitary gland tumors, which result in their premature death. The tumors occur with 100% penetrance in both POMC heterozygous and homozygous genotypes. Histological examinations reveal that tumors start from hyperplastic focal points of melanotrophic cells within the intermediate lobe. Based on the morphological and immunohistological features, we have classified the tumors as non-invasive, non-secreting, intermediate lobe adenomas. These findings uncover potential novel roles of melanocortins in the regulation of cell proliferation.

Prediagnostic Human T Lymphotropic Virus Type I Provirus Loads Were Highest in Jamaican Children Who Developed Seborrheic Dermatitis and Severe Anemia

In a recent clinical analysis of 308 Jamaican children, human T lymphotropic virus type I (HTLV-I) infection was found to be associated with significantly higher incidence rates of seborrheic dermatitis, eczema, and persistent hyperreflexia of the lower limbs and with nonsignificantly increased rates of severe anemia and abnormal lymphocytes. Results of examination of HTLV-I viral markers in the 28 HTLV-I-infected children provided virologic support for the epidemiologic associations of HTLV-I with seborrheic dermatitis and severe anemia in childhood.

Methylene blue dye as an alternative to isosulfan blue dye for sentinel lymph node localization

BACKGROUND

Our study describes the use of methylene blue dye as an alternative to isosulfan blue dye to identify the sentinel lymph node (SLN).

METHODS

A retrospective analysis was performed of 112 breast cancer patients (113 axillae) who underwent SLN biopsy (SLNB) with methylene blue dye and (99m)Tc-labeled sulfur colloid for SLN identification. All SLNs were submitted for intraoperative frozen section analysis, hematoxylin and eosin stain, and immunohistochemical evaluation. Patients with a pathologically negative SLN did not undergo further axillary lymph node dissection.

RESULTS

Of 112 patients who underwent SLNB, the SLN was identified in 107 (95.5%); 104 (92.8%) were identified by methylene blue dye. In a subset of 99 patients with recorded isotope status in relation to blue nodes, concordant identification with both dye and isotope was observed in 94 (94.9%). Of patients with identified SLNs, 32 (29.9%) of 107 contained metastatic disease, with 31 (96.9%) of 32 identified by methylene blue dye. The SLN was the only positive node in 18 (60.0%) of 30 patients.

CONCLUSIONS

SLNB with methylene blue dye is an effective alternative to isosulfan blue dye for accurately identifying SLNs in breast cancer patients.

Increased detection of serum HHV-6 DNA sequences during multiple sclerosis (MS) exacerbations and correlation with parameters of MS disease progression

In recent years, human herpesvirus 6 (HHV-6) has been investigated as a possible causative agent for MS. To determine if the detection of HHV-6 DNA in the serum of MS patients correlates with clinical parameters of MS disease progression, a total of 215 serum samples was obtained from 59 MS patients followed prospectively for a 5-month period. These samples were analyzed for the presence of HHV-6 DNA by nested PCR and compared in parallel to MS disease activity. HHV-6 DNA was amplified in 22% (4/18) of samples obtained during a period of clinical exacerbation. Significantly fewer (P = 0.008) sera, 5.6% (11/197), obtained from MS patients during clinical remission tested positive for the presence of HHV-6 DNA. This work demonstrates that the detection of serum HHV-6 DNA is significantly correlated with clinical exacerbations in MS. Moreover, the findings presented in this study have confirmed previous reports supporting an association between MS and HHV-6 and suggest a role for this human herpesvirus in the pathogenesis of MS.

Increased HTLV-I proviral load and preferential expansion of HTLV-I Tax-specific CD8+ T cells in cerebrospinal fluid from patients with HAM/TSP

To date, high human T-cell lymphotropic virus type I proviral load in patients with human T-cell lymphotropic virus type I-associated myelopathy/tropical spastic paraparesis has been reported and is thought to be related to the pathogenesis of human T-cell lymphotropic virus type I-associated myelopathy/tropical spastic paraparesis. However, the proviral load in cerebrospinal fluid has not been well investigated. We measured human T-cell lymphotropic virus type I proviral load in cerebrospinal fluid cells from human T-cell lymphotropic virus type I-associated myelopathy/tropical spastic paraparesis patients using real-time quantitative polymerase chain reaction (TaqMan). Human T-cell lymphotropic virus type I proviral load in cerebrospinal fluid cells were significantly higher than that of the matched peripheral blood mononuclear cells, and a high ratio of human T-cell lymphotropic virus type I proviral load in cerebrospinal fluid cells to peripheral blood mononuclear cells were observed in patients with short duration of illness. Human T-cell lymphotropic virus type I Tax-specific CD8+ T cells, as detected by peptide-loaded HLA tetramers, accumulated in cerebrospinal fluid compared with that in peripheral blood mononuclear cells, while the frequency of cytomegalovirus-specific CD8+ T cells in cerebrospinal fluid was reduced. These observations suggest that accumulation of both human T-cell lymphotropic virus type I-infected cells and preferential expansion of human T-cell lymphotropic virus type I-specific CD8+ cells in cerebrospinal fluid may play a role in the pathogenesis of human T-cell lymphotropic virus type I-associated myelopathy/tropical spastic paraparesis.

Recurrence rates in patients with central or retroareolar breast cancers treated with mastectomy or lumpectomy

BACKGROUND

Although breast conservation with lumpectomy and radiation treatment has become a commonly used treatment for breast cancer, there are little data to support the use of lumpectomy for central and retroareolar breast cancers. In this study, we investigate the local and distant recurrence rates of patients with central or retroareolar breast cancers treated with lumpectomy compared with mastectomy.

METHODS

This study provides a retrospective analysis of 99 patients, from 1981 to 2000, with central or retroareolar breast cancers treated with mastectomy or lumpectomy to determine the frequency of local and distant recurrence. The mastectomy and lumpectomy patients were compared with respect to recurrence and other prognostic factors including: tumor location, tumor size, axillary nodal status, and final surgical margins.

RESULTS

The overall frequency of local recurrence was 5 of 99 (5.0%) in the entire group, 3 of 67 (4.5%) and 2 of 32 (6.3%) of patients who underwent mastectomy and lumpectomy, respectively (P >0.99). Overall, 3 patients experienced a distant recurrence as a first event, with 2 patients (3.0%) in the mastectomy group and 1 patient (3.1%) in the lumpectomy group (P >0.99). The type of surgical management was not statistically significant related to either local or distant disease recurrence, with median time to local recurrence of 3.0 years for the mastectomy patients and 5.0 years for lumpectomy patients. Of the patients with central tumors who underwent mastectomy 2 of 42 (4.8%) developed local recurrences compared with those who had a lumpectomy, 1 of 21 (4.8%). Similarly for retroareolar tumors, the local recurrence rate was 1 of 25 (4.0%) for patients undergoing mastectomy and 1 of 11 (9.1%) for those undergoing lumpectomy (P >0.99).

CONCLUSIONS

In this study there was no significant difference in local or distant failure rates of those patients with central or retroareolar tumors treated with mastectomy versus lumpectomy. We conclude lumpectomy to be a reasonable treatment option for selected patients with central or retroareolar breast cancers.

Elevated serum and cerebrospinal fluid levels of soluble human herpesvirus type 6 cellular receptor, membrane cofactor protein, in patients with multiple sclerosis

Membrane cofactor protein (CD46) is a member of a family of glycoproteins that are regulators of complement and prevent activation of complement on autologous cells. Recently, CD46 has been identified as the cellular receptor for human herpesvirus Type 6 (HHV-6). Elevated levels of soluble CD46 have been described in several autoimmune disorders, and may be implicated in the pathogenesis of these diseases. As several reports have supported an association of HHV-6 and multiple sclerosis, it was of interest to compare levels of soluble CD46 in the sera of multiple sclerosis patients to that of healthy controls, other neurological disease controls, and other inflammatory disease controls. Using an immunoaffinity column comprised of immobilized monoclonal antibodies to CD46, serum levels of soluble CD46 were found to be significantly elevated in multiple sclerosis patients compared with healthy and other neurological disease controls. Moreover, multiple sclerosis patients who tested positive for HHV-6 DNA in serum had significantly elevated levels of soluble CD46 in their serum compared with those who were negative for HHV-6 DNA. A significant increase in soluble CD46 was also found in the serum of other inflammatory disease controls tested compared to healthy controls. Additionally, a significant correlation was demonstrated between levels of soluble CD46 in the serum and cerebrospinal fluid of multiple sclerosis patients. Collectively, these data suggest that elevated levels of soluble CD46 may contribute to the pathogenesis of inflammatory diseases, including multiple sclerosis.

CD8(+) T cells are an in vivo reservoir for human T-cell lymphotropic virus type I

It is thought that human T-cell lymphotropic virus type I (HTLV-I) preferentially infects CD4(+) T cells in vivo. However, observations of high HTLV-I proviral load in patients with HTLV-I-associated myelopathy/tropical spastic paraparesis suggest that HTLV-I may infect other cell types in addition to CD4(+) T cells. To identify in vivo T-cell tropisms of HTLV-I, real-time quantitative polymerase chain reaction (PCR) and intracellular protein staining were used. A high amount of HTLV-I proviral DNA was detected from purified CD8(+) T cells by quantitative PCR (between 1.64 and 62.83 copies of HTLV-I provirus per 100 isolated CD8(+) T cells). CD8(+) T cells expressed HTLV-I-related antigens (HTLV-I Tax and p19 protein) after a short time in cultivation. These results demonstrate that CD8(+) T cells are also infected with HTLV-I and express HTLV-I antigens at levels that are comparable to HTLV-I-infected CD4(+) cells. Therefore, CD8(+) cells are an additional viral reservoir in vivo for HTLV-I and may contribute to the pathogenesis of HTLV-I-mediated disorders.

In vitro spontaneous lymphoproliferation in patients with human T-cell lymphotropic virus type I-associated neurologic disease: predominant expansion of CD8+ T cells

Peripheral blood mononuclear cells (PBMCs) from patients with human T-cell lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) proliferate spontaneously in vitro. This spontaneous lymphoproliferation (SP) is one of the immunologic hallmarks of HAM/TSP and is considered to be an important factor related to the pathogenesis of HAM/TSP. However, the cell populations involved in this phenomenon have not yet been definitively identified. To address this issue, the study directly evaluated proliferating cell subsets in SP with a flow cytometric method using bromodeoxyuridine and Ki-67. Although both CD4+ and CD8+ T cells proliferated spontaneously, the percentage of proliferating CD8+ T cells was 2 to 5 times higher than that of CD4+ T cells. In addition, more than 40% of HTLV-I Tax11-19-specific CD8+ T cells as detected by an HLA-A*0201/Tax11-19 tetramer proliferated in culture. In spite of this expansion of HTLV-I-specific CD8+ T cells, HTLV-I proviral load did not decrease. This finding will help elucidate the dynamics of in vivo virus-host immunologic interactions that permit the coexistence of high HTLV-I-specific CD8+ cytotoxic T-lymphocyte responses and high HTLV-I proviral load in HAM/TSP.

Impairment in motor learning of somatostatin null mutant mice

Somatostatin was first identified as a hypothalamic factor which inhibits the release of growth hormone from the anterior pituitary (somatotropin release inhibitory factor, SRIF). Both SRIF and its receptors were subsequently found widely distributed within and outside the nervous system, in the adult as well as in the developing organism. Reflecting this wide distribution, somatostatin has been implicated regulating a diverse array of biological processes. These include body growth, homeostasis, sensory perception, autonomous functions, rate of intestinal absorption, behavior, including cognition and memory, and developmental processes. We produced null mutant mice lacking somatostatin through targeted mutagenesis. The mutant mice are healthy, fertile, and superficially indistinguishable from their heterozygous and wildtype littermates. A 'first round' phenotype screen revealed that mice lacking somatostatin have elevated plasma growth hormone levels, despite normal body size, and have elevated basal plasma corticosterone levels. In order to uncover subtle and unexpected differences, we carried out a systematic behavioral phenotype screen which identified a significant impairment in motor learning revealed when increased demands were made on motor coordination. Motor coordination and motor learning require an intact cerebellum. While somatostatin is virtually absent from the adult cerebellum, the ligand and its receptor(s) are transiently expressed at high levels in the developing cerebellum. This result suggests the functional significance of transient expression of SRIF and its receptors in the development of the cerebellum.

Integrated control of appetite and fat metabolism by the leptin-proopiomelanocortin pathway

Leptin deficiency results in a complex obesity phenotype comprising both hyperphagia and lowered metabolism. The hyperphagia results, at least in part, from the absence of induction by leptin of melanocyte stimulating hormone (MSH) secretion in the hypothalamus; the MSH normally then binds to melanocortin-4 receptor expressing neurons and inhibits food intake. The basis for the reduced metabolic rate has been unknown. Here we show that leptin administered to leptin-deficient (ob/ob) mice results in a large increase in peripheral MSH levels; further, peripheral administration of an MSH analogue results in a reversal of their abnormally low metabolic rate, in an acceleration of weight loss during a fast, in partial restoration of thermoregulation in a cold challenge, and in inducing serum free fatty acid levels. These results support an important peripheral role for MSH in the integration of metabolism with appetite in response to perceived fat stores indicated by leptin levels.

Pronociceptive actions of dynorphin maintain chronic neuropathic pain

Whereas tissue injury increases spinal dynorphin expression, the functional relevance of this upregulation to persistent pain is unknown. Here, mice lacking the prodynorphin gene were studied for sensitivity to non-noxious and noxious stimuli, before and after induction of experimental neuropathic pain. Prodynorphin knock-out (KO) mice had normal responses to acute non-noxious stimuli and a mild increased sensitivity to some noxious stimuli. After spinal nerve ligation (SNL), both wild-type (WT) and KO mice demonstrated decreased thresholds to innocuous mechanical and to noxious thermal stimuli, indicating that dynorphin is not required for initiation of neuropathic pain. However, whereas neuropathic pain was sustained in WT mice, KO mice showed a return to baselines by post-SNL day 10. In WT mice, SNL upregulated lumbar dynorphin content on day 10, but not day 2, after injury. Intrathecal dynorphin antiserum reversed neuropathic pain in WT mice at post-SNL day 10 (when dynorphin was upregulated) but not on post-SNL day 2; intrathecal MK-801 reversed SNL-pain at both times. Opioid (mu, delta, and kappa) receptor density and G-protein activation were not different between WT and KO mice and were unchanged by SNL injury. The observations suggest (1) an early, dynorphin-independent phase of neuropathic pain and a later dynorphin-dependent stage, (2) that upregulated spinal dynorphin is pronociceptive and required for the maintenance of persistent neuropathic pain, and (3) that processes required for the initiation and the maintenance of the neuropathic pain state are distinct. Identification of mechanisms that maintain neuropathic pain appears important for strategies to treat neuropathic pain.

Generation of dynorphin knockout mice

The opioid system has important roles in controlling pain, reward and addiction, and is implicated in numerous other processes within and outside the nervous system, such as mood states, immune responses, and prenatal developmental processes. The effects of the opioid system are mediated by at least three ligands, enkephalin, endorphin, and dynorphin, which act through the opioid receptors mu, delta, and kappa. In order to dissect the roles of individual components of the opioid system, mutant mice lacking single ligands or receptors are instrumental. We report here on the generation and initial characterization of a mutant mouse strain lacking pre-prodynorphin. Dynorphin 'knockout' mice are viable, healthy, and fertile and show no overt behavioral differences to wildtype littermates. Dynorphin knockout mice constitute a valuable tool for many research areas, among them research into pain, substance abuse, and epilepsy.

Tissue distribution and variant characterization of human herpesvirus (HHV)-6: increased prevalence of HHV-6A in patients with multiple sclerosis

Human herpesvirus (HHV)-6 has been associated with the pathogenesis of multiple sclerosis (MS) on the basis of serologic, molecular, and histopathologic studies. This study sought to determine the distribution of HHV-6 in different MS body fluids, including serum, saliva, urine, and peripheral blood lymphocytes. The study results extend the observation of an increased frequency of HHV-6 DNA in serum of patients with MS to the unique detection of viral sequences in urine of a subset of patients with MS. Moreover, the HHV-6 identified in these cell-free compartments was predominantly the HHV-6A variant, which has been reported to be neurotropic. These results support the hypothesis that HHV-6 may contribute to the MS disease process.

New diagnostic techniques and treatments for early breast cancer

OBJECTIVES

To review diagnostic techniques and treatments for early breast cancer, including radiologic techniques, biomarkers, surgical techniques, radiation therapy, adjuvant chemotherapy regimens, and hormonal therapy.

DATA SOURCES

Scientific and review articles, book chapters, and clinical practice.

CONCLUSIONS

Breast cancer is a major health problem. The advances in diagnosis and treatment of early breast cancer and the amount of information available make it difficult for patients to make diagnostic and treatment decisions.

IMPLICATIONS FOR NURSING PRACTICE

Oncology nurses need to be knowledgeable in the many advances in diagnostic and treatment techniques for early breast cancer to assist patients with difficult decisions.

Does sentinel lymphadenectomy improve staging and alter therapy in elderly women with breast cancer?

BACKGROUND

Routine axillary lymph node dissection (ALND) for elderly women with invasive breast cancer has been questioned because it rarely alters therapy yet carries a significant morbidity rate. Sentinel lymphadenectomy (SLND) improves axillary staging and alters therapy in women with T1 breast cancer, but it is not clear whether SLND alters therapy in elderly women with breast cancer.

METHODS

A prospective breast cancer data base was used to identify women 70 years old and older who underwent SLND for axillary staging of invasive breast cancer between 1991 and 1998.

RESULTS

There were 75 invasive breast cancers in 73 women. The mean patient age was 74.5 years (range, 70-90 years). Median tumor size was 1.4 cm (range, 0.1-6.2 cm). Of the 75 tumors, 42 (56%) had favorable primary characteristics; the remaining tumors had unfavorable characteristics. SLND was performed alone in 17 cases (23%) and was followed by completion ALND in 58 cases (77%). Positive lymph nodes were identified in 32 cases (43%); 26 (81.3%) were detected by hematoxylin and eosin stains, and 6 (18.7%) were detected by immunohistochemistry alone. Five patients (6.9%) received adjuvant chemotherapy. Seven patients (9.6%) received axillary/supraclavicular radiation for positive nodes. Ten (13.7%) of 73 patients had obvious alterations in therapy because of axillary nodal status. As a result of SLND, 3 (13.6%) of 22 patients with tumors 1.0 cm or smaller received tamoxifen, and 7 (15%) of 46 patients with tumors between 1.0 and 3.0 cm in size had changes in therapy. When patient and tumor characteristics were analyzed to determine relationships to therapeutic decision-making, nodal status was the variable most significantly associated with changes in therapy (P = .0001).

CONCLUSIONS

SLND improves axillary staging in elderly women with invasive breast cancer. Results of immunohistochemistry do not alter therapy in this group of individuals (P = .6367). In patients with small primary tumors, SLND alters therapy by increasing the number of patients receiving tamoxifen. In addition, SLND affects adjuvant systemic chemotherapy and regional radiotherapy in a significant number of patients with larger tumors, particularly tumors between 1.0 and 3.0 cm.

Prospective observational study of sentinel lymphadenectomy without further axillary dissection in patients with sentinel node-negative breast cancer

PURPOSE

Immediate complete axillary lymphadenectomy (ALND) after sentinel lymphadenectomy (SLND) has confirmed that tumor-negative sentinel nodes accurately predict tumor-free axillary nodes in breast cancer. Therefore, we hypothesized that SLND alone in patients with tumor-negative sentinel nodes would achieve axillary control, with minimal complications.

PATIENTS AND METHODS

Between October 1995 and July 1997, 133 consecutive women who had primary invasive breast tumors clinically </= 4 cm in diameter and no axillary lymphadenopathy were prospectively entered onto a trial of SLND using vital blue dye. Sentinel nodes were examined by standard microscopy or immunohistochemistry. SLND was the only axillary surgery if sentinel nodes were tumor-free. Completion ALND was performed only if sentinel nodes contained metastases or if they were not identified. Excluded from subsequent analysis were patients with unsuspected multifocal carcinoma and those who refused completion ALND. The complication and axillary recurrence rates after SLND without ALND were determined.

RESULTS

Sentinel nodes were identified in 132 (99%) of 133 patients. Eight patients were excluded from further analysis. Of the 125 assessable patients, 57 had tumor-positive sentinel nodes and one had an unsuccessful mapping procedure; these patients underwent completion ALND. In the remaining 67 patients (54%), SLND was the only axillary procedure. Complications occurred in 20 patients (35%) undergoing ALND after SLND but in only two patients (3%) undergoing SLND alone (P =.001). There were no local or axillary recurrences at a median follow-up of 39 months.

CONCLUSION

Complication rates are negligible after SLND alone. An absence of axillary recurrences supports SLND as an accurate staging alternative for breast cancer and suggests that routine ALND can be eliminated for patients with histopathologically negative sentinel nodes.

Sentinel node metastasis in patients with breast carcinoma accurately predicts immunohistochemically detectable nonsentinel node metastasis

BACKGROUND

Sentinel lymphadenectomy is highly accurate for identifying axillary metastasis from a primary breast carcinoma. Nonsentinel axillary lymph nodes (NSNs) are unlikely to contain tumor cells if the axillary sentinel node (SN) is tumor free. We previously showed that the size of the primary tumor and the size of its SN metastasis predict the risk of NSN tumor involvement detected by hematoxylin and eosin staining. This study used immunohistochemical staining (IHC) to determine the likelihood of NSN axillary metastasis in the presence of SN metastasis.

METHODS

Between 1991 and 1997, axillary lymphadenectomy was performed in 156 women (157 axillary basins) who had primary breast carcinoma with SN metastasis. By hematoxylin and eosin staining, we identified NSN metastasis in 55 axillae (35%). IHC was then used to re-examine all NSNs (1827 lymph nodes) from the remaining 102 axillae. The incidence of IHC-detected NSN involvement was analyzed with respect to clinical and tumor characteristics.

RESULTS

By using IHC, we identified NSN metastasis in 15 (14.7%) of the 102 axillae. By multivariate analysis, the size of the SN metastasis (P = .0001) and the size of the primary tumor (P = .038) were the only independent variables predicting NSN metastasis determined by using either hematoxylin and eosin staining or IHC. Only the number of SN metastases (1 vs. >1) was a significant (P = .04) predictor of IHC-detected NSN metastasis.

CONCLUSIONS

Use of IHC increases the likelihood of detection of NSN metastasis, and the risk of IHC-detected metastasis increases with the size of the SN metastasis and the size of the primary tumor. If SN involvement is micrometastatic (< or =2 mm) or detected by using IHC, tumor cells are unlikely to be found in other axillary lymph nodes in patients with a small primary tumor. The clinical significance of micrometastatic disease in lymph nodes is controversial, and a prospective randomized study is necessary to resolve this important issue.

Obesity in the mouse model of pro-opiomelanocortin deficiency responds to peripheral melanocortin

Pro-opiomelanocortin (POMC)-derived peptides (the melanocortins adrenocorticotropin, alpha-, beta- and gamma-melanocyte stimulating hormone; and the endogenous opioid beta-endorphin) have a diverse array of biological activities, including roles in pigmentation, adrenocortical function and regulation of energy stores, and in the immune system and the central and peripheral nervous systems. We show here that mice lacking the POMC-derived peptides have obesity, defective adrenal development and altered pigmentation. This phenotype is similar to that of the recently identified human POMC-deficient patients. When treated with a stable alpha-melanocyte-stimulating hormone agonist, mutant mice lost more than 40% of their excess weight after 2 weeks. Our results identify the POMC-null mutant mouse as a model for studying the human POMC-null syndrome, and indicate the therapeutic use of peripheral melanocortin in the treatment of obesity.

Isolation and characterization of the mouse homolog of the preprodynorphin (Pdyn) gene

We have isolated and sequenced the mouse preprodynorphin gene (Pdyn). The Pdyn gene can encode for six biologically active dynorphin peptides. The predicted mouse preprodynorphin has 90%, 67%, and 66% identity with the predicted rat, porcine, and human preprodynorphins, respectively. Using an RT-PCR technique, we show that the Pdyn gene starts being expressed at embryonic day 12.5, with a steep increase of expression by embryonic day 14.5; in the adult mouse it is expressed in the brain, but not in liver, heart, spleen, or kidney.