Free-flap failures and complications in an American oral and maxillofacial surgery unit.

Free tissue transfer is a reliable surgical technique that enables primary reconstruction following ablative surgery. Widely practised in many European units, acceptance into mainstream oral and maxillofacial surgery in the USA has been slow. The authors reviewed free flap practice patterns and outcomes in a US oral and maxillofacial surgery training program with specific emphasis on failures and complications to illustrate obstacles encountered during the initial phase of practice implementation. The demographic and clinical data of 71 consecutive patients who underwent microvascular reconstruction over 3 years (2002-2005) were reviewed. The study group included 48 males and 23 females who underwent 72 free tissue transfer procedures. Fourteen patients required operative exploration in the perioperative period. Six patients were explored for clinically compromised flaps. Thrombotic events occurred in 4 patients; 1 flap was successfully salvaged. There were 4 flap failures and 9 complications related to the donor site. Two perioperative deaths occurred from non-flap-related complications. Prolonged hospital stay and ICU utilization was observed in patients with surgical complications. Complications in this study did not affect the overall success rates of free-flaps. Salvage rates from thrombotic events were unaffected despite rigid flap monitoring protocols.

Research centers on minority institutions (RCMI): II.

The goal of the Research Centers in Minority Institutions (RCMI) is to develop biomedical and behavioral research at institutions with 50% minority enrollment (African Americans, Hispanics, Native Hawaiians, Pacific Islanders, Native Americans and Alaska Natives) who have been underrepresented in the biomedical sciences. The program has made available resources vital to scientific development and progress. While these resources have included, equipment, personnel supplies, Core laboratories etc, important effective approaches to research also have been emerging.

Research Centers in Minority Institutions (RCMI).

The Research Centers in Minority Institutions (RCMI) Program was initiated in the United States of America in 1985 as a congressionally mandated program. The mission of the RCMI Program is to expand the national capacity for the conduct of biomedical and behavioral research by developing the research infrastructure at institutions granting doctoral degrees in health or health-related sciences, that have 50% or greater enrollment of minorities (African Americans, Hispanics, Native Hawaiians and Pacific Islanders, Native Americans and Alaska Natives) that are underrepresented in the biomedical sciences. The program administration is based in the National Center for Research Resources (NCRR), at the National Institutes of Health (NIH), an agency of the Department of Health and Human Services (DHHS). Since its inception, the program has provided critical resources (core research laboratories, equipment, personnel, supplies, etc.) at each of the RCMI-funded institutions. This article is intended to provide an overview of the RCMI Program, outline the research areas and list contact persons for additional information on research and core resources at each of the current RCMI sites.

Effect of Partial Resistance on Phytophthora Stem Rot Incidence and Yield of Soybean in Ohio.

Phytophthora root and stem rot of soybean commonly causes losses in both stand and yield in Ohio. Environmental conditions which favor the pathogen typically occur in many areas of the state during late spring and summer. This study examined the performance of 12 soybean cultivars with partial resistance, with or without Rps genes, to different populations of Phytophthora sojae and various levels of disease pressure. The soybean cultivars were evaluated in seven field environments with and without metalaxyl over 4 years. There was a highly significant genotype-environment interaction which was due in part to variable disease pressure. The incidence of Phytophthora stem rot in subplots ranged from 0 to 10 plants in the most susceptible cultivar, Sloan, while significantly less stem rot developed in cultivars with high levels of partial resistance or partial resistance combined with an Rps gene in three of the seven environments. Metalaxyl applied in-furrow had a significant effect on early and final plant populations as well as yield (P < 0.001) in two of the seven environments, and for yield (P = 0.05) in one environment. This indicates that at these two environments, 2001 Lakeview and VanBuren, early season Phytophthora disease was controlled with the in-furrow fungicide treatment. When diverse populations of P. sojae were present, yields from soybean cultivars with high levels of partial resistance were significantly higher than those with low levels of partial resistance. Soybean cultivars with specific resistance genes Rps1k, Rps1k + Rps6, or Rps1k +Rps3a had higher yields than plants with only partial resistance in environments where race determination indicated that the populations of P. sojae present were not capable of causing disease on plants with the Rps1k gene. However, in an environment with very low disease pressure, yields of soybean cultivars with partial resistance were not significantly different from those with single Rps genes or Rps gene combinations. These results demonstrate that genetic traits associated with high levels of partial resistance do not have a negative effect on yield. Soybean cultivars that had the most consistent ranking across environments were those with moderate levels of partial resistance in combination with either Rps1k or Rps3a.

Pathogenic Diversity of Phytophthora sojae in Ohio Soybean Fields.

Problems with early season soybean stand establishment, and an increase in incidence of Phytophthora root and stem rot caused by Phytophthora sojae, prompted a reassessment of the pathogen population in Ohio. Earlier studies had indicated a potential for pathogen adaptation to commonly deployed Rps genes in soybeans. Fifty-seven fields, part of an earlier study in 1990 and 1991, along with 29 additional fields were sampled in either 1997 or 1999. Two soybean cultivars, Sloan (rps) and Resnik (Rps1k), were used as bait in a seedling bioassay to isolate P. sojae from the soil samples. P. sojae was recovered from 82 of the 86 fields sampled. Of the 429 isolates recovered from these soils, 325 and 104 were baited with soybean cultivars Sloan and Resnik, respectively. The P. sojae population in Ohio increased in the number of pathotypes (races) as well as in complexity since the earlier surveys. There were 72 and 202 pathotypes identified on 8 and 13 Rps gene differentials, respectively, in the current study. When the data were compared by location, 96, 65, 73, 78, 51, and 52% of the locations had at least one isolate with virulences to Rps1a, Rps1b, Rps1c, Rps1k, Rps3a, and Rps6, respectively. The mean complexity, the number of susceptible interactions on 8 differentials, increased from 3.01 to 4.06 between 1991 and 1997/1999. In addition, the pathogenic diversity as measured by the Shannon index increased from 2.71 to 3.28 for isolates recovered from the 57 fields sampled in both surveys. Producers whose fields were sampled were surveyed to determine if changes in the P. sojae population could be linked with production practices. There was a significant association between (P ≤ 0.05) reduced tillage practices and the presence of isolates that had virulence to Rps1k; reduced tillage fields also had isolates with virulence to a greater number of differentials. Due to the percentage of isolates that have virulence to many of the Rps genes, it is questionable how long a single Rps gene or several stacked Rps genes will remain viable disease management tools for P. sojae, unless a novel Rps gene is identified.

Temperature, Moisture, and Seed Treatment Effects on Rhizoctonia solani Root Rot of Soybean.

The effects of temperature and soil moisture on infection and disease development by Rhizoctonia solani on soybean were studied individually. In addition, the anastomosis group of R. solani isolates recovered from soybean from 35 fields in 15 counties was determined. All of the 44 isolates recovered in this study were AG-2-2 IIIB. Five isolates of R. solani were able to infect and colonize soybean roots and hypocotyls at 20, 24, 28, and 32°C in growth chamber studies. The temperatures evaluated in this study were not limiting to the isolates tested. In greenhouse studies, nine R. solani isolates and a noninoculated control were evaluated at 25, 50, 75, and 100% soil moisture holding capacity (MHC). Root weights were greater and percent stand averages higher at 50 and 75% than at 25 or 100% MHC; however, as percentage of control, the main effect on percent moisture for percent stand, plant height, or root weight was not significant. There were significant differences among the isolates for the percent stand, root rot rating, and root fresh weight of soybean in each study. In both temperature and moisture studies, the R. solani isolates could be separated as predominantly causing (i) seed rot, as detected by greatly reduced plant stand; (ii) root rot generally having no effect on plant stand but a high root rot rating and low root weight; or (iii) hypocotyl lesions, having no effect on plant stand, a low root rot score, and a high number of red lesions on the hypocotyl. In the greenhouse seed treatment evaluations of five fungicides, there was no fungicide by isolate interaction using these pathogenic types of R. solani. None of the seed treatments evaluated in this study provided 100% control of the four isolates tested. Due to the wide range of environmental factors that permit R. solani infection and disease on soybeans, other control measures that last all season, such as host resistance, should be emphasized.

Beneficial Effects of Fungicide Seed Treatments for Soybean Cultivars with Partial Resistance to Phytophthora sojae.

Phytophthora sojae is a yield-limiting soybean pathogen in areas where soils remain saturated for long periods of time. P. sojae has been successfully managed with single dominant resistance genes (Rps genes). The proportion of fields with populations of P. sojae capable of causing susceptible interactions with many of the Rps genes has increased in number. The fungicides metalaxyl and mefenoxam have been used both as in-furrow and seed treatments to provide protection against damping-off caused by P. sojae. To determine the plant age when partial resistance and Rps genes are effective against P. sojae, we evaluated a greenhouse assay in which soybean seeds were planted and inoculated with a zoospore suspension to compare the disease reaction of soybean seeds and seedlings. Efficacy of different fungicide rates also was evaluated using the cultivar with partial resistance with this inoculation technique. Seeds and seedlings of a cultivar with high levels of partial resistance were susceptible to infection by P. sojae while those of a cultivar with an Rps gene were resistant. For the cultivar with partial resistance, reductions in percent emergence and the number of damped-off seedlings were significantly higher for plants inoculated at the day of planting compared to inoculations of plants with unifoliates present (5 days after planting). Results also indicate that fungicide seed treatment on cultivars with partial resistance may be beneficial when the environmental conditions that favor P. sojae infections occur prior to soybean emergence. This greenhouse assay appears to be useful in examining overall fungicide efficacy; however, it did not detect consistent and quantifiable differences in rates of seed treatment fungicides.

Evidence for paracrine regulation of experimental metastasis in 13762NF rat mammary adenocarcinoma cell clones.

The ability of tumor cell lines to form experimental pulmonary metastases is determined in part by characteristics which are stable over many cell generations; in part by characteristics that are acquired by adaptation or phenotypic instability; but also in part by characteristics which may change over less than one cell generation. This study was designed to examine the hypothesis that tumor cells secrete and respond to paracrine factors which can reversibly modulate metastasis. The number of experimental lung metastases increased for 13762NF rat mammary adenocarcinoma cell clones MTF7 and MTLn3 as they approach 100% confluence. This observation corresponded to increased attachment to bovine brain capillary and bovine corneal endothelial monolayers and to ability of tumor cells to invade reconstituted basement membrane barriers in the Membrane Invasion Culture System (MICS), but did not correspond to cell cycle distribution, susceptibility to NK or PMN cell killing or average cell size/Coulter volume. While changing confluence did not qualitatively alter metastatic potential, modification of metastasis in a quantitative manner suggested that some properties pertinent to metastasis are transient and manipulatable. Tumor cell-conditioned medium (CM) collected from donor cells grown to defined levels of confluence when placed onto recipient cells reversibly raised or lowered metastatic potential depending upon the medium source and confluence of the recipient cells. CM from 20% confluent donor cultures reduced recipient cell metastatic potential. In contrast CM from 100% confluent cultures increased metastatic potential of subconfluent cells. Replacement with fresh unconditioned medium or leaving the medium unchanged did not alter experimental metastasis. These data suggest that metastasis involves steps which may be influenced by paracrine factors elaborated by tumor cells.

Tumor progression- and metastasis-associated proteins identified using a model of locally recurrent rat mammary adenocarcinomas.

A recently established model for local breast cancer recurrence using the 13762NF rat mammary adenocarcinoma was used to evaluate biologic and biochemical properties related to clinical outcome for this class of tumors. Sublines isolated from local tumor regrowths following surgical resection differed from each other and from the 'parental' cell lines for multiple phenotypes, including metastatic propensity. Local recurrence- and primary tumor-derived sublines were examined by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE), lectin binding to electrophoretically separated proteins, and lactoperoxidase-catalyzed cell surface iodination; and differential protein patterns were compared to tumor progression and metastatic potential. 2D-PAGE revealed several quantitatively different spots which correlated with lung colonization potential. In particular, quantities of an apparently unique, non-cell-surface protein, P50.9 (Mr approximately 50,900, pI approximately 7.3) correlated inversely with metastatic propensity, suggesting that it may be associated with, among other possibilities, the negative regulation of the metastatic phenotype. P50.9 was unrelated to four similarly sized metastasis-associated proteins--tumor autocrine motility factor; the rat analog of tumor suppressor, p53; rat cytokeratin 14 or procathepsin D--as determined by amino acid analysis. A major wheat germ agglutinin binding sialoglycoprotein, gp93 (Mr approximately 93,000), was present in smaller amounts as cells were passaged in vivo and re-established as in vitro cultures [MTF7 greater than 'primary' tumor-derived lines (sc1, sc3) much greater than local recurrence-derived lines (LR1, LR1a, LR3, LR4, LR5, LR6)]. Besides cell surface glycoprotein losses, two of six local recurrence-derived sublines expressed a wheat germ agglutinin-binding sialoglycoprotein, gp110 (Mr approximately 110,000), previously undetected on any of the other cell lines including the parental populations. gp110 was found in LR3 and LR6 which were relatively highly metastatic; however, correlation with metastatic potential failed because gp110 was not present on the metastatic parental cell line, MTF7. These results demonstrate specific quantitative and qualitative protein differences associated with the selection of locally recurrent mammary tumors.

Large changes in intracellular pH and calcium observed during heat shock are not responsible for the induction of heat shock proteins in Drosophila melanogaster.

Heat shock caused significant changes in intracellular pH (pHi) and intracellular free calcium concentration [( Ca2+]i) which occurred rapidly after temperature elevation. pHi fell from a resting level value at 25 degrees C of 7.38 +/- 0.02 (mean +/- standard error of the mean, n = 15) to 6.91 +/- 0.11 (n = 7) at 35 degrees C. The resting level value of [Ca2+]i in single Drosophila melanogaster larval salivary gland cells was 198 +/- 31 nM (n = 4). It increased approximately 10-fold, to 1,870 +/- 770 nM (n = 4), during a heat shock. When salivary glands were incubated in calcium-free, ethylene glycol-bis(beta-aminoethyl ether)-N,N',N'-tetraacetic acid (EGTA)-buffered medium, the resting level value of [Ca2+]i was reduced to 80 +/- 7 nM (n = 3), and heat shock resulted in a fourfold increase in [Ca2+]i to 353 +/- 90 nM (n = 3). The intracellular free-ion concentrations of Na+, K+, Cl-, and Mg2+ were 9.6 +/- 0.8, 101.9 +/- 1.7, 36 +/- 1.5, and 2.4 +/- 0.2 mM, respectively, and remained essentially unchanged during a heat shock. Procedures were devised to mimic or block the effects of heat shock on pHi and [Ca2+]i and to assess their role in the induction of heat shock proteins. We report here that the changes in [Ca2+]i and pHi which occur during heat shock are not sufficient, nor are they required, for a complete induction of the heat shock response.