Ecological opportunity and the origin of adaptive radiations.

Ecological opportunity--through entry into a new environment, the origin of a key innovation or extinction of antagonists--is widely thought to link ecological population dynamics to evolutionary diversification. The population-level processes arising from ecological opportunity are well documented under the concept of ecological release. However, there is little consensus as to how these processes promote phenotypic diversification, rapid speciation and adaptive radiation. We propose that ecological opportunity could promote adaptive radiation by generating specific changes to the selective regimes acting on natural populations, both by relaxing effective stabilizing selection and by creating conditions that ultimately generate diversifying selection. We assess theoretical and empirical evidence for these effects of ecological opportunity and review emerging phylogenetic approaches that attempt to detect the signature of ecological opportunity across geological time. Finally, we evaluate the evidence for the evolutionary effects of ecological opportunity in the diversification of Caribbean Anolis lizards. Some of the processes that could link ecological opportunity to adaptive radiation are well documented, but others remain unsupported. We suggest that more study is required to characterize the form of natural selection acting on natural populations and to better describe the relationship between ecological opportunity and speciation rates.

Familial and racial determinants of tumour suppressor genes promoter hypermethylation in breast tissues from healthy women.

To determine the hypermethylation status of the promoter regions of tumour suppressor genes in breast tissues from healthy women and identify the determinants of these epigenetic changes. Questionnaires and breast tissues were collected from healthy women without a history of cancer and undergoing reduction mammoplasty (N= 141). Methylation for p16(INK4), BRCA1, ERalpha and RAR-beta promoter regions from breast tissues were determined by methylation specific PCR. Associations were examined with chi-square and Fisher's exact test as well as logistic regression. All statistical tests were two-sided. p16(INK4), BRCA1, ERalpha and RAR-beta hypermethylation were identified in 31%, 17%, 9% and 0% of the women, respectively. Women with BRCA1 hypermethylation had an eight-fold increase in the risk of ERalpha hypermethylation (P= 0.007). p16(INK4) hypermethylation was present in 28% of African-Americans, but 65% in European-Americans (P= 0.02). There was an increased likelihood of p16(INK4) or BRCA1 hypermethylation for women with family history of cancer (OR 2.3; 95%CI: 1.05-4.85 and OR 5.0; 95%CI: 1.55-15.81, respectively). ERalpha hypermethylation was associated with family history of breast cancer (OR 6.6; 95%CI: 1.58-27.71). After stratification by race, p16(INK4) in European-Americans and BRCA1 hypermethylation in African-Americans were associated with family history of cancer (OR 3.8; 95%CI: 1.21-12.03 and OR 6.5; 95%CI: 1.33-31.32, respectively). Gene promoter hypermethylation was commonly found in healthy breast tissues from women without cancer, indicating that these events are frequent and early lesions. Race and family history of cancer increase the likelihood of these early events.

Acellular dermis-assisted breast reconstruction.

BACKGROUND: In 2004, the authors reported their findings with placement of tissue expanders for breast reconstruction in the partial submuscular position, the equivalent of the "dual-plane" technique for breast augmentation. Limitations with subpectoral expander placement include difficulty controlling the lower pole of the pocket during expansion, unprotected device coverage by a thin inferior mastectomy flap, possible effacement of the inframammary fold, and limited control over the superior migration of the pectoralis major muscle. This study aimed to examine the safety and efficacy of an acellular dermal sling in providing inferolateral support to the device during immediate breast reconstruction and expansion. METHODS: This study prospectively investigated 58 breasts of 43 consecutive women who underwent immediate breast reconstruction with tissue expanders and acellular dermis. After completion of adjuvant therapy and expansion, the devices were exchanged for implants. The patients were tracked through January, 2007. The study parameters included demographic information, oncologic data, complications, and aesthetic outcomes. RESULTS: The mean time required to complete reconstruction was 8.6 months. The overall complication rate after expander/acellular dermis placement was 12%, whereas the complication rate after exchange to implants was 2.2%. The aesthetic outcome for reconstructed breasts did not differ significantly from that for the control subjects who had no surgery. CONCLUSIONS: Acellular dermis appears to be a useful adjunct in immediate prosthetic breast reconstruction. Acellular dermis-assisted breast reconstruction has a low complication rate, helps to reconstruct an aesthetically pleasing breast, and facilitates expeditious completion of the reconstruction.

Putting the "landscape" in landscape genetics.

Landscape genetics has emerged as a new research area that integrates population genetics, landscape ecology and spatial statistics. Researchers in this field can combine the high resolution of genetic markers with spatial data and a variety of statistical methods to evaluate the role that landscape variables play in shaping genetic diversity and population structure. While interest in this research area is growing rapidly, our ability to fully utilize landscape data, test explicit hypotheses and truly integrate these diverse disciplines has lagged behind. Part of the current challenge in the development of the field of landscape genetics is bridging the communication and knowledge gap between these highly specific and technical disciplines. The goal of this review is to help bridge this gap by exposing geneticists to terminology, sampling methods and analysis techniques widely used in landscape ecology and spatial statistics but rarely addressed in the genetics literature. We offer a definition for the term "landscape genetics", provide an overview of the landscape genetics literature, give guidelines for appropriate sampling design and useful analysis techniques, and discuss future directions in the field. We hope, this review will stimulate increased dialog and enhance interdisciplinary collaborations advancing this exciting new field.

Cutaneous wound analysis using hyperspectral imaging.

A correlative bright-field and hyperspectral analysis of full-thickness, cutaneous wounds in a porcine model was undertaken to investigate the efficacy of hyperspectral imaging as an alternate method for wound identification. Analysis of a randomly selected specimen yielded distinct spectral signatures for cutaneous regions of interest including the epidermis, injured dermis, and normal dermis. The scanning of the entire specimen group using these hyperspectral signatures revealed an exclusionary, pseudo-color pattern whereby a central wound region was consistently defined by a unique spectral signature. An algorithm was derived as an objective tool for the comparison of the wound regions defined by the hyperspectral classification versus the pathologists' manual tracings. The dimensions of the wound identified in the hyperspectral assay did not differ significantly from the wound region identified by the pathologists using standard bright-field microscopy. These data indicate that hyperspectral analysis may provide a high-throughput alternative for wound estimation that approximates standard bright-field imaging and pathologist evaluation.

Improvements in cardiovascular risk profile with large-volume liposuction: a pilot study.

In this study, the authors investigated the physiologic effects of the altered body composition that results from surgical removal of large amounts of subcutaneous adipose tissue. Fourteen women with body mass indexes of greater than > 27 kg/m2 underwent measurements of fasting plasma insulin, triglycerides, cholesterol, body composition by dual-energy x-ray absorptiometry (DXA), resting energy expenditure, and blood pressure before and after undergoing large-volume ultrasound-assisted liposuction. There were no significant intraoperative complications. Body weight had decreased by 5.1 kg (p < 0.0001) by 6 weeks after liposuction, with an additional 1.3-kg weight loss (p < 0.05) observed between 6 weeks and 4 months after surgery, for a total weight loss of 6.5 kg (p < 0.00006). Body mass index decreased from (mean +/- SEM) 28.8 +/- 2.3 to 26.8 +/- 1.5 kg/m2 (p < 0.0001). This change in body weight was primarily the result of decreases in body fat mass: as assessed by DXA, lean body mass did not change (43.8 +/- 3.1 kg to 43.4 +/- 3.6 kg, p = 0.80), whereas DXA total body fat mass decreased from 35.7 +/- 6.3 to 30.1 +/- 6.5 kg (p < 0.0001). There were significant decreases in fasting plasma insulin levels (14.9 +/- 6.5 mIU/ml before liposuction versus 7.2 +/- 3.2 mIU/ml 4 months after liposuction, p < 0.007), and systolic blood pressure (132.1 +/- 7.2 versus 120.5 +/- 7.8 mmHg, p < 0.0002). Total cholesterol, high-density lipoprotein cholesterol, plasma triglycerides, and resting energy expenditure values were not significantly altered after liposuction. In conclusion, over a 4-month period, large-volume liposuction decreased weight, body fat mass, systolic blood pressure, and fasting insulin levels without detrimental effects on lean body mass, bone mass, resting energy expenditure, or lipid profiles. Should these improvements be maintained over time, liposuction may prove to be a valuable tool for reducing the comorbid conditions associated with obesity.

Alternative filler materials and new implant designs: what's available and what's on the horizon?

Despite ample evidence that silicone gel-filled implants do not cause systemic illness, they are still not available in the United States for widespread use. At this point, saline-filled implants are widely available for use, and assuming favorable outcomes of the relevant silicone studies, some forms of silicone gel-filled implants could be approved by the FDA and be available as soon as 2003. Other products under preliminary consideration by the FDA for eventual studies include the 150 series and the cohesive silicone gel-filled 410 series by McGhan, and the NovaGold implant by NovaMed. Assuming favorable study results, one or more could be approved by the FDA by the year 2004. Any products not yet submitted to the FDA for review of study designs by this time are not likely to be available in the United States in the next 4 or 5 years.

Breast augmentation with reduced-height anatomic implants: the pros and cons.

The reduced-height anatomic saline-filled implant has certain advantages. It has a distinct footprint and profile that allows the creation of a breast with relatively exaggerated width and abbreviated height. This creation suits certain anatomic situations and often is preferred by women seeking a more natural-looking augmentation, without excessive upper pole fullness. The use of any anatomic design implant requires some dimensional planning and more precise pocket dissection. Although the risk for rotational deformities could be expected to be increased, clinically significant rotational deformities have not been a major problem.

Empiric treatment of gonorrhea and chlamydia in the ED.

A retrospective study was conducted on female patients who were screened for Chlamydia trachomatis and Neisseria gonorrhea. The purpose of the study was to determine if any factors predict empiric therapy at the index visit. Of 911 patients enrolled in the study, 100 were found to have positive DNA screens and 54 were given empiric therapy. A logistic regression was used to test the ability of age, ethnicity, DNA probe result and provider type (physician or midlevel provider), to predict empiric treatment. DNA probe result and provider type were the only 2 factors that were found to predict empiric therapy. A subsequent analysis using a Cochran-Mantel-Hanszel test to control for DNA probe result revealed that the provider type remained the only variable that predicted empiric treatment.

Postmastectomy reconstruction of the previously augmented breast: diagnosis, staging, methodology, and outcome.

Although many of the health and safety issues associated with breast augmentation have been thoroughly discussed over the past decade, the literature is remarkably silent regarding postmastectomy reconstruction of the previously augmented breast. A retrospective review of the senior author's reconstructive practice was performed for the years 1983 through March of 1999, revealing 21 women who underwent postmastectomy breast reconstruction after previous breast augmentation. For purposes of measuring aesthetic results, these 21 patients were matched to a carefully selected control group of 15 patients. They were also compared with other, larger populations, including 777 of the senior author's other breast reconstructions, the breast cancer registry at the Lombardi Cancer Center in Washington, D.C., and several large, published epidemiologic studies. The interval between the previous augmentation and the diagnosis of breast cancer ranged from 9 months to 18 years, with a mean of 9.3 years. None of the previous augmentation implants was ruptured at the time of mastectomy. Of the nine patients with previous subpectoral augmentation, cancer was detected mammographically in five (56 percent), whereas of the 12 patients with previous subglandular augmentation, cancer was first detected mammographically in only three (25 percent). This difference was not statistically significant (p = 0.2). Overall, eight of the study patients' tumors (38 percent) were first detected mammographically, which is similar to other published reports of breast cancer patients in the general population. Seventy-one percent of the 21 study patients were node-negative, which also compares favorably with other published series. Sixteen of the women with previous augmentation (76 percent) had purely prosthetic reconstructions. Flaps were used in the other five reconstructions (23 percent): three latissimus dorsi flaps (14 percent) and two transverse rectus abdominis musculocutaneous flaps (9 percent). All five flaps were used in patients who had undergone radiation therapy. Throughout the senior author's entire reconstructive practice history, transverse rectus abdominis musculocutaneous flaps were more frequently used [282 of 777 nonaugmented reconstructions (36 percent)], whereas latissimus dorsi flaps were less frequently used [17 of 777 nonaugmented reconstructions (2.2 percent)] (p < 0.001). The cosmetic results of the breast reconstructions in the previously augmented study group were generally good-to-excellent, with a mean score by blinded observers of 3.35 of a possible 4.0. These results were comparable to or better than those in the matched controls, who scored a mean of 3.0.

Breast reconstruction with implants and expanders.

Breast reconstruction with expanders and implants provides an excellent option in the properly selected patient. Techniques for reconstruction have evolved significantly over the past 30 years with the development of more sophisticated devices and improvement in surgical procedures. Several options exist, each with its own advantages and disadvantages. Two-stage breast reconstruction using a textured device with an anatomic shape and integrated valve seems to provide the most consistent and reproducible results in most patients. Those patients with small, minimally ptotic breasts may be candidates for either single-stage implant reconstruction or reconstruction with an adjustable device. Advantages of expander and implant reconstruction over other techniques include relative ease of the procedure; no distant donor-site morbidity; use of tissue of similar color, texture, and sensation; reduced operative time; and more rapid postoperative recovery.

Improvements in cardiovascular risk profile after large-volume lipoplasty: a 1-year follow-up study.

BACKGROUND: Large-volume lipoplasty changes body composition during a single surgical intervention by selectively decreasing subcutaneous adipose tissue. Positive health benefits, previously reported for a cohort of 14 women at 4 months after surgery, include significant decreases in weight, systolic blood pressure, and fasting insulin levels. OBJECTIVE: In the present study, we sought to determine whether the benefits of altering body composition by large-volume liposuction observed at 4 months are sustained over longer periods of time. METHODS: Subjects were seen for an additional follow-up visit approximately 1 year (range 10 to 21 months) after surgery. Fasting insulin levels were measured in the 8 patients who had preoperative fasting insulin levels higher than 12 muU/mL. Weight, systolic and diastolic blood pressure, heart rate, and body circumferences were measured in all 14 subjects. RESULTS: Compared with data obtained before surgery and 4 months after surgery, results at 10 to 21 months after lipoplasty showed that the improvements in body weight, systolic blood pressure, and fasting insulin levels observed 4 months after the procedure had been maintained. CONCLUSIONS: Should these results be confirmed in larger studies, lipoplasty may prove to be a valuable tool for reducing some of the co-morbid conditions associated with obesity. (Aesthetic Surg J 2001;21:527-531.).

Evaluation of abdominal sensibility after TRAM flap breast reconstruction.

One commonly expressed concern regarding transverse rectus abdominis myocutaneous (TRAM) flap breast reconstruction surgery is the return of sensation to the abdomen. Although many studies have focused on abdominal wall muscle incompetence or herniation, there is limited literature discussing postoperative abdominal sensation. The purpose of this study was to assess abdominal sensation a minimum of 1 year after pedicled TRAM flap surgery for breast reconstruction. Twenty-five female patients who underwent TRAM flap breast reconstruction a minimum of 1 year before the study were compared with 10 female volunteer controls. Subject and control abdomens were specifically divided into 12 zones, then assessed for superficial touch, superficial pain, temperature, and vibration using various techniques. Fischer's exact test was used for analysis with the p value set at p = 0.05. The degree to which superficial touch was affected was then tested using Semmes-Weinstein monofilaments. Student's t test was used for analysis with the p value set at p = 0.05. For all four sensory modalities, subjects were found to have decreased sensation in zones 5 and 8, the supraumbilical and infraumbilical regions. This was statistically significant. When assessed with Semmes-Weinstein monofilaments, the sensation of the subjects' abdomens was significantly decreased compared with controls. Significance was found in all zones. This study clearly demonstrates that there is a significant and persistent reduction in abdominal sensibility following TRAM flap surgery. The distribution of the deficits is consistent and involves the midline supraumbilical and infraumbilical regions. The TRAM flap has become the procedure of choice for postmastectomy autogenous breast reconstruction. It provides the plastic surgeon with a relatively safe, reliable, and aesthetically pleasing method of breast reconstruction. Since its inception, the TRAM flap and its abdominal closure have undergone numerous modifications designed to minimize donor-site morbidity and create a natural-looking breast. In addition to creating an aesthetically pleasing breast, the TRAM flap has the potential advantage of postoperative improvement in abdominal contour.

Control of fever by continuous, low-dose diclofenac sodium infusion in acute cerebral damage patients.

OBJECTIVES: The aim of this study was to assess the efficacy and safety of low doses of diclofenac sodium (DCF) in attaining normothermia with minimal major side effects in patients with acute cerebral damage. The study was designed to verify the adequate, prolonged antipyretic action of DCF infusion, to quantify its haemodynamic and cerebral impact and to assess any negative effect on renal and liver function. DESIGN: Retrospective, cohort study on prospectively collected data. SETTING: Intensive care unit (ICU) of a university hospital. PATIENT POPULATION: Five patients with subarachnoid haemorrhage and seven severe head-trauma victims with febrile illness of various infectious origin. INTERVENTIONS: Continuous i.v. infusion of a low dose (0.04 mg/kg/h) of DCF for 48 h. MEASUREMENTS AND RESULTS: Systemic and cerebral haemodynamic data were collected at 4 h intervals for 8 h before diclofenac infusion and 48 h after. Renal and liver functions were monitored. Normothermia, defined as external temperature < 37.5 degrees Celsius (degrees C), was achieved in all cases. Intracranial pressure was significantly lowered and mean arterial pressure was unaffected, so cerebral perfusion pressure rose after DCF. Hepatic and renal function were not altered in the 48 h post DCF. Mean urinary output was preserved at high flow and was not influenced by DCF. CONCLUSIONS: Continuous infusion of low-dose DCF attained normothermia without any major cerebral or systemic side effects. Renal and liver functions were unaffected. Once normothermia was achieved, intracranial and cerebral perfusion pressure improved.

Risk factors for second urinary tract infection among college women.

To better understand the etiology of recurrent urinary tract infection (UTI), the authors followed a cohort of 285 female college students with first UTI for 6 months or until second UTI. A first UTI due to Escherichia coli was followed by a second UTI three times more often than was a non-E. coli first UTI (24 vs. 8%; p = 0.02). In a logistic regression analysis limited to the 224 women from the University of Michigan Health Service and the University of Texas at Austin Health Service from September 1992 to December 1994, with a first UTI due to E. coli, vaginal intercourse increased the risk of a second UTI with both a different (odds ratio (OR) = 1.60, 95% confidence interval (CI): 1.19, 2.15) and the same (OR = 1.37, 95% CI: 0.91, 2.07) uropathogen, as did using a diaphragm, cervical cap, and/or spermicide (same uropathogen: OR = 1.53, 95% CI: 0.95, 2.47; different uropathogen: OR = 1.77, 95% CI: 1.22, 2.58). Condom use decreased the risk of a second UTI caused by a different uropathogen (OR = 0.68, 95% CI: 0.48, 0.99) but had no effect on a second UTI caused by the same E. coli (OR = 0.99; 95% CI: 0.66, 1.50). Type or duration of treatment was not associated with a second UTI. Although the risk of second UTI is strongly influenced by sexual behavior, women with a first UTI caused by E. coli are more likely than are those with a non-E. coli first UTI to have a second UTI within 6 months.