Improving cold storage and processing traits in potato through targeted gene knockout.

Cold storage of potato tubers is commonly used to reduce sprouting and extend postharvest shelf life. However, cold temperature stimulates the accumulation of reducing sugars in potato tubers. Upon high-temperature processing, these reducing sugars react with free amino acids, resulting in brown, bitter-tasting products and elevated levels of acrylamide--a potential carcinogen.

Improved soybean oil quality by targeted mutagenesis of the fatty acid desaturase 2 gene family.

Soybean oil is high in polyunsaturated fats and is often partially hydrogenated to increase its shelf life and improve oxidative stability. The trans-fatty acids produced through hydrogenation pose a health threat. Soybean lines that are low in polyunsaturated fats were generated by introducing mutations in two fatty acid desaturase 2 genes (FAD2-1A and FAD2-1B), which in the seed convert the monounsaturated fat, oleic acid, to the polyunsaturated fat, linoleic acid.

Structural variants in the soybean genome localize to clusters of biotic stress-response genes.

Genome-wide structural and gene content variations are hypothesized to drive important phenotypic variation within a species. Structural and gene content variations were assessed among four soybean (Glycine max) genotypes using array hybridization and targeted resequencing. Many chromosomes exhibited relatively low rates of structural variation (SV) among genotypes.

Targeted mutagenesis of duplicated genes in soybean with zinc-finger nucleases.

We performed targeted mutagenesis of a transgene and nine endogenous soybean (Glycine max) genes using zinc-finger nucleases (ZFNs). A suite of ZFNs were engineered by the recently described context-dependent assembly platform--a rapid, open-source method for generating zinc-finger arrays. Specific ZFNs targeting dicer-like (DCL) genes and other genes involved in RNA silencing were cloned into a vector under an estrogen-inducible promoter.

Phenotypic and genomic analyses of a fast neutron mutant population resource in soybean.

Mutagenized populations have become indispensable resources for introducing variation and studying gene function in plant genomics research. In this study, fast neutron (FN) radiation was used to induce deletion mutations in the soybean (Glycine max) genome. Approximately 120,000 soybean seeds were exposed to FN radiation doses of up to 32 Gray units to develop over 23,000 independent M2 lines.

The composition and origins of genomic variation among individuals of the soybean reference cultivar Williams 82.

Soybean (Glycine max) is a self-pollinating species that has relatively low nucleotide polymorphism rates compared with other crop species. Despite the low rate of nucleotide polymorphisms, a wide range of heritable phenotypic variation exists. There is even evidence for heritable phenotypic variation among individuals within some cultivars.

Disruption of imprinting by mutator transposon insertions in the 5' proximal regions of the Zea mays Mez1 locus.

Imprinting is a form of epigenetic gene regulation in which alleles are differentially regulated according to the parent of origin. The Mez1 gene in maize is imprinted such that the maternal allele is expressed in the endosperm while the paternal allele is not expressed. Three novel Mez1 alleles containing Mutator transposon insertions within the promoter were identified.

Maternal and paternal alleles exhibit differential histone methylation and acetylation at maize imprinted genes.

Imprinting is an epigenetically controlled form of gene regulation in which the expression of a gene is based on its parent of origin. This epigenetic regulation is likely to involve allele-specific DNA or histone modifications. The relative abundance of eight different histone modifications was tested at various regions in several imprinted maize (Zea mays) genes using a chromatin immunoprecipitation protocol coupled with quantitative allele-specific single nucleotide polymorphism assays.

Gene expression analyses in maize inbreds and hybrids with varying levels of heterosis.

Background: Heterosis is the superior performance of F1 hybrid progeny relative to the parental phenotypes. Maize exhibits heterosis for a wide range of traits, however the magnitude of heterosis is highly variable depending on the choice of parents and the trait(s) measured. We have used expression profiling to determine whether the level, or types, of non-additive gene expression vary in maize hybrids with different levels of genetic diversity or heterosis.

Natural variation for alleles under epigenetic control by the maize chromomethylase zmet2.

The contribution of epigenetic alterations to natural variation for gene transcription levels remains unclear. In this study, we investigated the functional targets of the maize chromomethylase ZMET2 in multiple inbred lines to determine whether epigenetic changes conditioned by this chromomethylase are conserved or variable within the species. Gene expression microarrays were hybridized with RNA samples from the inbred lines B73 and Mo17 and from near-isogenic derivatives containing the loss-of-function allele zmet2-m1.

Genomic imprinting, methylation and molecular evolution of maize Enhancer of zeste (Mez) homologs.

Imprinted gene expression refers to differential transcription of alleles depending on their parental origin. To date, most examples of imprinted gene expression in plants occur in the triploid endosperm tissue. The Arabidopsis gene MEDEA displays an imprinted pattern of gene expression and has homology to the Drosophila Polycomb group (PcG) protein Enhancer-of-zeste (E(z)).

Inguinal hernia repair: results using an open preperitoneal approach.

Background: Laparoscopic surgical approaches to the repair of inguinal hernias have shown the advantages of placing mesh in the preperitoneal space. Despite those advantages, laparoscopic hernia repairs have been associated with increased cost, longer operating times, and advanced laparoscopic skills. An open preperitoneal approach has the benefit of mesh in the preperitoneal position without the disadvantages of a laparoscopic procedure.

Laparoscopic suturing and knot tying: a comparison of standard techniques to a mechanical assist device.

Background: Suturing and knot tying are basic skills for surgeons. Performing these tasks laparoscopically can be a tedious, time-consuming endeavor associated with much frustration. We evaluated a mechanically assisted suture and pretied knot device (Quik-Stitch) for performing the basic tasks of suturing and knot tying.

Hand-assisted laparoscopic splenectomy: indications and technique.

Introduction: Laparoscopic splenectomy has become the procedure of choice for those patients who need to have a splenectomy. The skills required to perform a laparoscopic splenectomy are not easy to learn and therefore may limit the availability of this procedure to patients.

Methods: We present a hand-assisted technique that allows the performance of a laparoscopic splenectomy safely and rapidly by surgeons without a great deal of experience with this procedure.

Prophylactic antibiotics are not indicated in clean general surgery cases.

Background: In assigning risk of infection, the traditional wound classification system has been replaced by the National Nosocomial Infection Surveillance (NNIS) system. NNIS classification is determined by procedure length, wound cleanliness, and ASA status. To date, no prophylactic antibiotic guidelines have been proposed for the NNIS system.

Does peer-reviewed publication change the habits of surgeons?

Background: From April 1994 to December 1995 a prospective randomized trial was conducted at our institution comparing outcomes of laparoscopic and open appendectomy. It demonstrated no significant advantage to laparoscopic appendectomy. Our current study evaluates whether surgeon's habits at our hospital have been influenced by our previously published study.

The value of limited computed tomography with rectal contrast in the diagnosis of acute appendicitis.

Background: Multiple nonrandomized studies demonstrate the accuracy of computed tomography (CT) scan in diagnosing appendicitis. This study compared CT scan with standard management in diagnosing appendicitis.

Methods: This was a prospective randomized study of patients who received general surgery consultation for appendicitis.

Prophylactic antibiotics for elective laparoscopic cholecystectomy: are they necessary?

Hypothesis: Prophylactic antibiotic treatment in elective laparoscopic cholecystectomy does not lower the already low infection rate associated with this procedure.

Design And Setting: Prospective double-blind randomized trial at a community-based training hospital.

Patients: Four hundred fifty patients undergoing elective laparoscopic cholecystectomy were randomized into 1 of 3 treatment arms: (1) preoperative cefotetan disodium, 1g intravenously; (2) preoperative cefazolin, 1g intravenously; and (3) intravenous placebo.

Use of fine needle aspiration for solid breast lesions is accurate and cost-effective.

Background: Palpable breast tumors have traditionally been diagnosed with open biopsy or core biopsy. We propose fine needle aspiration biopsy (FNA) as a reliable, cost-saving initial procedure in these patients.

Methods: Eighty-five palpable solid breast masses of the breast in 85 patients were classified by a combination of physical examination, mammography, and/or ultrasound as probably benign, indeterminate, or highly suspicious for cancer.

Laparoscopic vs open appendectomy. Prospective randomized study of outcomes.

Objective: To compare open appendectomy (OA) with laparoscopic appendectomy (LA) for length of the operation, complications, postoperative pain control, length of hospitalization, postdischarge recovery time, and hospital charges.

Design: Prospective randomized clinical trial of patients with acute appendicitis.

Setting: Tertiary care, urban teaching hospital.

Surgical complications of continuous ambulatory peritoneal dialysis.

Surgical experience with 260 consecutive patients with chronic renal failure receiving continuous ambulatory peritoneal dialysis (CAPD) at one medical center from 1980 to 1989 is reviewed. Patients received CAPD for a mean of 24.2 months (range: 3 days to 91 months).

Intimal breakdown causing failure of human umbilical vein graft.

Early graft failure secondary to intimal breakdown with subsequent hemorrhage into and dissection of the wall of a modified human umbilical cord vein allograft occurred. Early recognition and immediate graft replacement will undoubtedly minimize further morbidity to the patient. To our knowledge, this is the first case of early graft failure from this cause described in the literature.