Collagen regulation of let-7 in pancreatic cancer involves TGF-ß1-mediated membrane type 1-matrix metalloproteinase expression.

Pancreatic ductal adenocarcinoma (PDAC) is associated with a pronounced collagen-rich fibrosis known as desmoplastic reaction; however, the role of fibrosis in PDAC is poorly understood. In this report we show that collagen can regulate the tumor suppressive let-7 family of microRNAs in pancreatic cancer cells. PDAC cells growing in 3D collagen gels repress mature let-7 without affecting the precursor form of let-7 in part through increased expression of membrane type 1-matrix metalloproteinase (MT1-MMP, MMP-14) and ERK1/2 activation. PDAC cells in collagen also demonstrate increased TGF-ß1 signaling, and blocking TGF-ß1 signaling attenuated collagen-induced MT1-MMP expression, ERK1/2 activation and repression of let-7 levels. Although MT1-MMP overexpression was not sufficient to inhibit let-7 on 2D tissue culture plastic, overexpression of MT1-MMP in PDAC cells embedded in 3D collagen gels or grown in vivo repressed let-7 levels. Importantly, MT1-MMP expression significantly correlated with decreased levels of let-7 in human PDAC tumor specimens. Overall, our study emphasizes the interplay between the key proteinase MT1-MMP and its substrate type I collagen in modulating microRNA expression, and identifies an additional mechanism by which fibrosis may contribute to PDAC progression.

The effects of bevacizumab on postoperative complications in patients undergoing colorectal and pancreatic cancer resection.

Bevacizumab (Avastin™; rhuMab VEGF), a monoclonal antibody targeting vascular endothelial growth factor (VEGF), has seen increased use in the perioperative treatment of colorectal and pancreatic cancer. Little is known, however, regarding its impact on surgical outcomes in patients undergoing resection. The objective of this review was to examine if the addition of bevacizumab to existing neoadjuvant regimens increases morbidity after cancer resection.

Outcomes after pancreatectomy for intraductal papillary mucinous neoplasms of the pancreas: an institutional experience.

PURPOSE: To evaluate the experience with pancreatectomy for intraductal papillary mucinous neoplasm (IPMN) at a single academic institution. METHODS: A prospective pancreatic database was reviewed and identified 43 patients with IPMN who were managed operatively. Clinicopathologic features and predictors of outcome were examined. The World Health Organization pathologic classification of IPMN was utilized. RESULTS: IPMN was diagnosed in 21% of patients who underwent pancreatic resection for solid or cystic mass lesions. Ninety-five percent of patients were symptomatic. Patients were managed with total pancreatectomy, pancreaticoduodenectomy, distal pancreatectomy, central pancreatectomy, or enucleation. Nine patients had adenomas, 14 had borderline neoplasms, 10 had carcinoma in situ, and 9 had invasive carcinoma. Overall, 23 patients (53%) had lesions with main duct involvement. Frozen section transection margins were positive for malignancy in 2 patients. With a mean follow-up of 17 months, the 5-year disease-specific survival for patients with main duct involvement was 67%. The 5-year disease-specific survival for patients with benign lesions was 100%, and 61% for patients with malignant lesions (P = .02). The presence of symptoms, increased CA 19-9, and tumor size were not predictive of malignancy. Increased serum bilirubin concentrations were predictive of malignancy (P = .03). Main duct involvement was also associated with malignancy (P < .02). CONCLUSIONS: Cancer is found in 65% of patients with IMPN involving the main duct. Based on our data, patients with symptomatic, main duct involvement, especially those with an increased serum bilirubin, should be offered resection. Alternatively, patients with side branch IPMN may be managed conservatively.

The role of sentinel lymph node biopsy in Paget's disease of the breast.

BACKGROUND: Sentinel lymph node (SLN) biopsy has become a standard of care for axillary lymph node staging in breast cancer and appears suitable for virtually all patients with clinically node-negative (cN0) invasive disease. However, its role in Paget's disease of the breast, a condition in which invasion may or may not be present, remains undefined. METHODS: Among 7,083 consecutive SLN biopsy procedures, we retrospectively identified 39 patients with Paget's disease of the breast. Nineteen patients had no associated clinical/radiographic features ("Paget's only"), and 20 patients had associated clinical/radiographic findings ("Paget's with findings"). RESULTS: The mean ages for the Paget's alone and with findings groups were 63.6 and 49.6 years, respectively. The use of breast conservation therapy was 32% in the Paget's alone group and 10% in the Paget's with findings group. Invasive carcinoma was found in 27% of patients in the Paget's alone group and 55% of patients in the Paget's with findings group. The success rate of SLN biopsy was 98%, and the mean number of SLNs removed was 3 in both groups. In the entire cohort of Paget's disease, 28% (11/39) of the patients had positive SLNs (11%, Paget's alone; 45%, Paget's with findings). CONCLUSION: In our "Paget's only" cohort, invasive cancer was found in 27% of cases and positive SLNs in 11%. SLN biopsy should be considered in all patients with Paget's disease of the breast, whether associated clinical/radiographic findings are present.

Hand dominance and performance in a laparoscopic skills curriculum.

BACKGROUND: This study evaluated the influence of hand dominance on skill acquisition during a basic laparoscopic skills curriculum. METHODS: A total of 27 surgical residents (5 postgraduate year 3 [PGY-3] and 22 PGY-2 residents) participated in a 4-week laparoscopic skills curriculum. The residents were pre- and posttested on six laparoscopic tasks during weeks 1 and 4. During weeks 2 and 3, the residents attended a proctored practice session. The results were compared using analysis of variance (ANOVA), (with significance determined by a p value less than 0.05. RESULTS: The posttest scores were significantly higher than the pretest scores. On the pretest, lefthand-dominant (LHD) surgeons (n = 4) performed significantly better than righthand-dominant (RHD) surgeons (n = 23). In the analysis of individual task pretest scores, LHD surgeons performed significantly better on pattern cutting and vessel loop application. Posttest analysis of overall performance did not show significant differences between the RHD and LHD surgeons. CONCLUSIONS: Participation in a laparoscopic skills curriculum improved overall performance. The LHD surgeons demonstrated better initial performance, but posttest comparison showed no difference between the two groups.

Tamoxifen, raloxifene and the prevention of breast cancer.

The recognition of a new group of drugs, now named selective estrogen receptor modulators (SERMs) has revolutionized prospects for the prevention of breast cancer. New agents will continue to be tested against tamoxifen, the first SERM and an established treatment of ER positive breast cancer. Raloxifene a related SERM is used to treat and prevent osteoporosis with the potential beneficial side effect of preventing breast cancer. The Study of Tamoxifen and Raloxifene (STAR) trial will establish whether raloxifene is an improvement over tamoxifen. Most importantly, emerging information about the molecular pharmacology of SERMs will be used to decipher the mechanism of action at specific target sites around a woman's body. This knowledge can be used to design new SERMs and advance the prospects for multifunctional medicine to prevent breast cancer, osteoporosis and coronary heart disease.

Novel antitumor effect of estradiol in athymic mice injected with a T47D breast cancer cell line overexpressing protein kinase Calpha.

PURPOSE: Resistance to tamoxifen (TAM) represents a significant challenge to the management of breast cancer. We previously reported that the estrogen receptor (ER)-negative hormone-independent T47D:C42 cell line has both elevated protein kinase Calpha (PKCalpha) protein expression and basal activator protein-1 activity compared with the parental ER+ (hormone-dependent) T47D:A18 cell line. Stable transfection of PKCalpha to the T47D:A18 breast cancer cell line results in increased basal activator protein-1 activity, reduced ER function, increased proliferation rate, and hormone-independent growth (Tonetti et al., Br. J. Cancer, 83: 782-791, 2000). In this report, we further characterize the role of PKCalpha overexpression in vivo to elucidate a possible molecular mechanism of tamoxifen resistance. EXPERIMENTAL DESIGN: To determine whether the T47D:A18/PKCalpha cell line would produce hormone-independent tumors in athymic mice, we injected T47D:A18, T47D:A18/neo, or the T47D:A18/PKCalpha20 cell clones bilaterally into the mammary fat pads of athymic mice. Tumor growth was evaluated following treatment with estradiol (E2), TAM, and the pure antiestrogen, ICI 182,780. RESULTS: Mice receiving either T47D:A18 or T47D:A18/neo cells produced tumors that grew in response to E2 treatment, whereas the untreated control and TAM-treated groups showed no tumor growth. Interestingly, mice receiving the T47D:A18/PKCalpha20 clone produced tumors in both the control and TAM groups, whereas tumor growth was inhibited in mice treated with E2. PKCalpha was also overexpressed in an MCF-7 tumor model that also exhibited TAM-stimulated and E2-induced regression. CONCLUSIONS: These results suggest that overexpression of PKCalpha in breast tumors results in hormone-independent tumor growth that cannot be inhibited by TAM treatment. Furthermore, the finding that E2 has an antitumor effect on breast tumors overexpressing PKCalpha is a novel observation that may have important therapeutic implications.

Control of the estrogen-like actions of the tamoxifen-estrogen receptor complex by the surface amino acid at position 351.

Tamoxifen is a valuable therapeutic agent with applications in the treatment and prevention of breast cancer. However, the development of drug resistance limits the usefulness of tamoxifen therapy. One form of drug resistance in breast cancer is tamoxifen-stimulated growth. We have addressed a mechanism how the tamoxifen-estrogen receptor (ER) complex can convert from being a blocking to stimulatory signal in breast cancer. We have described an effective assay system to study the action of antiestrogen-ER complex through the activation of transforming growth factor alpha gene in situ. The MDA-MB-231 breast cancer cells were stably transfected with cDNAs for wtER (D351), mutant Asp351Tyr ER (D351Y) and mutant Asp351Gly ER (D351G). The D351Y ER can enhance the estrogenic properties of 4OHT and change the pharmacology of raloxifene by converting it from antiestrogen to estrogen. We hypothesized that alterations in the charge of amino acid (aa) 351, and changes in the interaction with the side chain of an antiestrogen, are critical for the subsequent estrogenicity of the complex. Our goal was (1) to modulate the estrogenicity of the antiestrogen-ER complex by different aa substitutions at position 351 and (2) to examine the role of alterations in the side chain of antiestrogens on the estrogenicity of the complex. Substitution of tyrosine for aspartate at aa351 results in increased estrogenicity for a series of tamoxifen derivatives-ER complexes and the conversion of EM 652-ER and GW 7604-ER complexes from antiestrogenic to estrogen-like. Substitution of glycine for aspartate at aa 351 results in the conversion of 4OHT-ER complex from estrogen-like to antiestrogenic. We propose that the side chain of antiestrogens either neutralizes or displaces the charge at aspartate 351 thereby removing a charged site for the opportunistic binding of a novel coactivator. If no charge is present (D351G) then no coactivator can bind and the complex with any antiestrogen is not estrogen-like. However, if the charge is extended beyond the reach of an antiestrogen side chain (D351Y), then the coactivators bind and compounds are estrogen-like. The establishment of a relationship between the structure of the antiestrogen-ER complex and its function will enhance the development of novel compounds with unique biological activities and potentially avoid premature drug resistance.

Evaluation of serum calcium levels in predicting hypoparathyroidism after total/near-total thyroidectomy or parathyroidectomy.

Hospital stays for thyroid and parathyroid surgery have decreased significantly with selected patients staying under 8 hours. Strategies to recognize hypocalcemia postoperatively vary. We examined timed postoperative calcium levels to determine how long one needs to monitor patients for hypoparathyroidism. We analyzed 120 consecutive patients having total/near-total thyroidectomy and/or parathyroidectomy between April 1998 and October 1999. Total and ionized serum calcium levels were obtained at 8, 16, and 22 hours postoperatively. Strict criteria for significant hypoparathyroidism were defined as a symptomatic patient, a total calcium value of less than 7.2 mg/dL, or an ionized calcium value of less than 1.0 mmol/L. Eighteen patients (15%) met criteria for hypocalcemia. The 8-hour ionized calcium level identified 40 per cent of those that needed supplementation. With the inclusion of the 16-hour ionized calcium value 94.5 per cent of patients who met criteria were identified. Of the 74 patients who had not previously received calcium at 22 hours after surgery only one patient with hypocalcemia was identified. Serial calcium values postoperatively add to the costs associated with an overnight hospital stay. In addition to clinical examination an ionized calcium level 16 hours postoperatively is sufficient to identify significant hypoparathyroidism in the majority of patients.

Allosteric silencing of activating function 1 in the 4-hydroxytamoxifen estrogen receptor complex is induced by substituting glycine for aspartate at amino acid 351.

The active metabolite of tamoxifen, 4-hydroxytamoxifen (4-OHT), is used in the laboratory for mechanistic studies of antiestrogen action. This compound binds to the estrogen receptor alpha (ER) and silences activating function 2 (AF2) in the ligand binding domain, but activating function 1 (AF1) at the other end of the ER remains constitutive and is considered to be ligand independent. Amino acid D351 in the ligand binding domain appears to be critical for interactions with the antiestrogenic side chain of antiestrogens. We have devised an assay to evaluate the biological activity of 351 mutant ERs and antiestrogens at the transforming growth factor alpha (TGFalpha) gene in situ (J. I. MacGregor Schafer et al., Cancer Res., 59: 4308-4313, 1999). The substitution of glycine for aspartate at position 351 results in the conversion of the 4-OHT:ER complex from estrogen-like to completely antiestrogenic. In cells stably expressing D351G ER, the ER retains responsiveness to estradiol (E2) and also retains antiestrogenic responsiveness to both raloxifene and ICI 182,780. The relative binding affinity of E2 for D351G ER (0.77 +/- 0.17 x 10(-9) M) is comparable with wild-type ER (0.42 +/- 0.08 x 10(-9) M). In addition, the D351G ER retains the ability to bind SRC-1 in the presence of E2, thus D351G ER AF2 activity has not been compromised. We also used a cell line stably expressing an ER with a triple mutation in helix 12 (D538A, E542A, and D545A) that ablated AF2 activity, which resulted in decreased effects of E2, suggesting that both AF1 and AF2 activity are required for maximal estrogen activity in MDA-MB-231 cells. Interestingly, the triple mutation also completely reduced the estrogen-like actions of 4-OHT. We propose that a specific mutation at amino acid 351 can allosterically silence AF1 in the 4-OHT:ER complex by either preventing the binding of coactivators or encouraging the binding of a corepressor molecule. We suggest that the 4-OHT-specific site responsible for estrogen-like actions can be referred to as AF2b. This binding site would consist of at least four carboxylic acids at amino acids 351 and 538, 542 and 545 in helix 12 to permit coactivator docking for gene activation. The AF2b site is distinct from AF2 for E2 action. Further studies will provide insight into the estrogen-like actions of tamoxifen in select tissues and breast tumors and identify a significant mechanism of drug resistance to tamoxifen.

Antitumor action of physiological estradiol on tamoxifen-stimulated breast tumors grown in athymic mice.

The estrogen receptor (ER)-positive MCF-7 breast cancer cell line can be transplanted into athymic mice and grown into tumors with estradiol (E2) support. Tamoxifen (TAM) blocks E2-stimulated tumor growth; however, continuous TAM treatment results in transplantable tumors within a year that will grow with either E2 or TAM (M. M. Gottardis and V. C. Jordan, Cancer Res., 48: 5183-5187, 1988). Although this model may represent the development of TAM resistance for the treatment of advanced breast cancer, no laboratory model exists to study the exposure of breast cancer to 5 years of adjuvant TAM therapy. We have addressed this issue and report the development and characterization of two tumor lines, MCF-7TAM and MT2, which have been serially transplanted into TAM-treated athymic mice for >5 years. The MCF-7TAM tumor rapidly regresses in response to E2 and then about 50% of tumors regrow in response to E2. Interestingly, tumor regression does not occur if TAM treatment is stopped, probably because E2 levels are too low in ovariectomized athymic mice. The development of the antitumor effect of E2 was documented for MT2 tumors over a 1-year period; TAM-stimulated tumor growth was retained, but E2 caused progressively less of a stimulatory effect. Most importantly, E2-stimulated tumors that regrew after initial tumor regression in both MCF-7TAM and MT2 lines were again responsive to TAM to block E2-stimulated growth. Unlike MCF-7 tumors, the MT2 tumor line contains a single point mutation, Asp351Tyr, in the ER, which was retained after the development of E2-stimulated regrowth. The mutation is associated with increased estrogen-like actions for the TAM-ER complex (A. S. Levenson et al., Br. J. Cancer, 77: 1812-1819, 1998), but we conclude that the mutant ER is not required for TAM resistance. On the basis of the new breast cancer models presented, we propose a cyclic sensitivity to TAM that may have important clinical implications: (a) it is possible that a woman's own estrogen may produce an antitumor effect on the presensitized micrometastatic disease after 5 years of TAM. Long-term antitumor action occurs because the drug is stopped, but resistance accumulates and tumors start to grow if adjuvant therapy is continued; and (b) although in the clinic TAM-resistant tumors respond to second-line therapies that cause estrogen withdrawal, e.g., pure antiestrogens or aromatase inhibitors, estrogen therapy may also be effective and return the tumor to TAM responsiveness. In this way, a hormone-responsive tumor may be controlled longer in the patient with advanced disease.

Targeted antiestrogens for the prevention of breast cancer.

This commentary explores the recent experience with and the basis for the use of selective estrogen receptor modulators (SERMs) to prevent breast cancer. Chemoprevention has been a goal for many years. As newer agents are unveiled, they will continue to be tested against tamoxifen, the current standard for the treatment and prevention of breast cancer. Raloxifene holds the promise of treating osteoporosis with the beneficial side effect of breast cancer prevention. The Study of Tamoxifen and Raloxifene (STAR) trial and prior prevention studies will be discussed in an attempt understand the bridge from the laboratory to the clinic.

Chondritis of the ear: a late sequela of deep partial thickness burns of the face.

Chondritis of the ear is a late sequela of deep partial thickness burns of the face. It is the purpose of this article to describe two patients who came to the emergency department 21 days and 35 days after sustaining deep partial thickness burns of the face from explosions. The patients were hospitalized for incision and drainage of the infected wound that included excision of the infected cartilage complemented by systemic antibiotic therapy.

Grease burns of the hand: preventable injuries.

Grease burns to the hand represent a serious and preventable hazard. These injuries account for over 10% of all major burns seen in the emergency department. These burns occur when the cook attempts to move a pan with burning cooking oil and inadvertently spills the oil on the hand holding the pan. These burns are usually full thickness because of either the high temperatures of the flaming oils or the subsequent ignition of clothing. This article describes a patient who received severe partial and full thickness burns to the dominant hand following a grease burn in the domestic setting. Prevention through improved consumer education and warning labels for cooking oils should reduce the incidence of these serious injuries.

Does the architectural design of burn centers comply with the Americans with Disabilities Act?

Title III of the Americans with Disabilities Act (ADA) requires that hospitals and burn centers be designed and constructed so that all public and common-use areas are accessible. At least 10% of patient bedrooms and toilets must be accessible to persons with mobility disorders. The purpose of this study was to determine whether four hospitals with burn centers complied with Title III of the ADA. The burn centers agreed to participate in this study only if they were first assured anonymity, because of the Health Care Financing Administration of the U.S. Department of Health and Human Services requires that each hospital comply. With use of the ADA accessibility guidelines, we developed a survey instrument that was validated by a state government building inspector. This tool was used to inspect the burn center facility and common use areas in four hospitals with burn centers. In the four hospitals, numerous architectural barriers to persons with disabilities were noted. No burn center had a designated accessible room for persons with disabilities. The bedrooms, bathrooms, sinks, bathtubs, and toilets were not accessible to persons with disabilities. The common-use areas in the hospitals, in contrast, had few architectural barriers to persons with disabilities. Only one burn center had plans to eliminate architectural barriers in its hospital. Because the four hospitals with burn centers had numerous architectural barriers for persons with disabilities, it can be concluded they do not comply with Title III of the ADA and are subject to severe penalty from the Health Care Financing Administration and the U.S. Department of Justice.

First metatarsophalangeal joint arthroplasties in the Commonwealth of Virginia.

This retrospective analysis of arthroplasty of the first metatarsophalangeal joint documents the incidence of surgery as well as the selection of the commercially available implants. During a 1-year period, 1994, arthroplasties were performed in 47 of the 1.7 million subscribers to Trigon Blue Cross Blue Shield of Virginia. Women received the majority of the arthroplasties (83%). Of the 47 cases, the silicone implant was predominantly used (83%). The most common indications for arthroplasty were hallux valgus (30%) and hallux rigidus (28%). Podiatrists performed 79% of the procedures, while orthopedic surgeons performed the remaining 21% of the cases. A prospective study is needed that will assess the long-term performance of the different implants.

An overview of first metatarsophalangeal joint implant arthroplasty.

The metatarsophalangeal joint of the great toe often requires an arthroplasty to correct joint disease and pain. Today, joint replacement systems are combinations of components manufactured to optimize biological ingrowth, mechanical interlock, press fit, and cementing. Three different types of arthroplasties are available to foot surgeons: the double stem hinged silicone implant, the two-component joint mimicking implant, and a hemi-implant available for the phalanx. No comprehensive studies on very large populations have been conducted to accurately evaluate the beneficial long-term effects of these implants. This review article describes the development of the toe arthroplasty, details the commercially available implants, and addresses the advantages and adverse effects of each implant.

A new device for securing meshed split-thickness skin grafts.

This report describes the design, operation, and biomechanical performance of the Auto Suture Multifire Graftac-S disposable surgical staplers and absorbable tacks. The performance of this reloadable stapler has been compared to that of the Auto Suture Multifire Premium disposable skin stapler. The Premium stapler forms stainless steel staples to close the wound. The Graftac-S ejects absorbable tacks into the graft from a cartridge, which can be reloaded during a single operation. In two clinical trials of 10 patients each, the Graftac-S delivered absorbable tacks which were biocompatible and successfully secured the graft to the wound. The most obvious advantage of this device is that it obviates the need to remove the staples from the wound later. By the tenth postoperative day, about 90% of the tacks had extruded spontaneously, thereby reducing the amount of postoperative care required; discomfort to the patient during removal of the stainless steel staples is eliminated.