Compact zinc finger architecture utilizing toxin-derived cytidine deaminases for highly efficient base editing in human cells

Nucleobase editors represent an emerging technology that enables precise single-base edits to the genomes of eukaryotic cells. Most nucleobase editors use deaminase domains that act upon single-stranded DNA and require RNA-guided proteins such as Cas9 to unwind the DNA prior to editing. However, the most recent class of base editors utilizes a deaminase domain, DddAtox, that can act upon double-stranded DNA. Here, we target DddAtox fragments and a FokI-based nickase to the human CIITA gene by fusing these domains to arrays of engineered zinc fingers (ZFs). We also identify a broad variety of Toxin-Derived Deaminases (TDDs) orthologous to DddAtox that allow us to fine-tune properties such as targeting density and specificity. TDD-derived ZF base editors enable up to 73% base editing in T cells with good cell viability and favorable specificity.

Inducible CRISPR-targeted "knockdown" of human gut Bacteroides in gnotobiotic mice discloses glycan utilization strategies

Understanding how members of the human gut microbiota prioritize nutrient resources is one component of a larger effort to decipher the mechanisms defining microbial community robustness and resiliency in health and disease. This knowledge is foundational for development of microbiota-directed therapeutics. To model how bacteria prioritize glycans in the gut, germfree mice were colonized with 13 human gut bacterial strains, including seven saccharolytic Bacteroidaceae species. Animals were fed a Western diet supplemented with pea fiber. After community assembly, an inducible CRISPR-based system was used to selectively and temporarily reduce the absolute abundance of Bacteroides thetaiotaomicron or B. cellulosilyticus by 10- to 60-fold. Each knockdown resulted in specific, reproducible increases in the abundances of other Bacteroidaceae and dynamic alterations in their expression of genes involved in glycan utilization. Emergence of these "alternate consumers" was associated with preservation of community saccharolytic activity. Using an inducible system for CRISPR base editing in vitro, we disrupted translation of transporters critical for utilizing dietary polysaccharides in Phocaeicola vulgatus, a B. cellulosilyticus knockdown-responsive taxon. In vitro and in vivo tests of the resulting P. vulgatus mutants allowed us to further characterize mechanisms associated with its increased fitness after knockdown. In principle, the approach described can be applied to study utilization of a range of nutrients and to preclinical efforts designed to develop therapeutic strategies for precision manipulation of microbial communities.

Improving CRISPR-Cas9 Genome Editing Efficiency by Fusion with Chromatin-Modulating Peptides

Bacterial-derived CRISPR-Cas9 nucleases have become a common tool in genome engineering. However, the editing efficiency by even the best-crafted Cas9 nucleases varies considerably with different genomic sites, and efforts to explore the vast natural Cas9 diversity have often met with mixed or little success. Here, we show that modification of the widely used Streptococcus pyogenes Cas9 by fusion with chromatin-modulating peptides (CMPs), derived from high mobility group proteins HMGN1 and HMGB1, histone H1, and chromatin remodeling complexes, improves its activity by up to several fold, particularly on refractory target sites. We further show that this CMP fusion strategy (termed CRISPR-chrom) is also effective in improving the activities of smaller Cas9 nucleases from Streptococcus pasteurianus and Campylobacter jejuni, as well as four newly characterized Cas9 orthologs from Bacillus smithii, Lactobacillus rhamnosus, Mycoplasma canis, and Parasutterella excrementihominis. Our findings suggest that this CRISPR-chrom strategy can be used to improve established Cas9 nucleases and facilitate exploration of novel Cas9 orthologs for genome modification.

Improving CRISPR Gene Editing Efficiency by Proximal dCas9 Targeting

Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and CRISPR-associated (Cas) systems function as an adaptive immune system in bacteria and archaea for defense against invading viruses and plasmids (Barrangou and Marraffini, 2014). The effector nucleases from some class 2 CRISPR-Cas systems have been repurposed for heterologous targeting in eukaryotic cells ( Jinek et al., 2012 ; Cong et al., 2013 ; Mali et al., 2013 ; Zetsche et al., 2015 ). However, the genomic environments of eukaryotes are distinctively different from that of prokaryotes in which CRISPR-Cas systems have evolved. Mammalian heterochromatin was found to be a barrier to target DNA access by Streptococcus pyogenes Cas9 (SpCas9), and nucleosomes, the basic units of the chromatin, were also found to impede target DNA access and cleavage by SpCas9 in vitro ( Knight et al., 2015 ; Hinz et al., 2015 ; Horlbeck et al., 2016 ; Isaac et al., 2016 ). Moreover, many CRISPR-Cas systems characterized to date often exhibit inactivity in mammalian cells and are thus precluded from gene editing applications even though they are active in bacteria or on purified DNA substrates. Thus, there is a need to devise a means to alleviate chromatin inhibition to increase gene editing efficiency, especially on difficult-to-access genomic sites, and to enable use of otherwise inactive CRISPR-Cas nucleases for gene editing need. Here we describe a proxy-CRISPR protocol for restoring nuclease activity of various class 2 CRISPR-Cas nucleases on otherwise inaccessible genomic sites in human cells via proximal targeting of a catalytically dead Cas9 ( Chen et al., 2017 ). This protocol is exemplified here by using Campylobacter jejuni Cas9 (CjCas9) as nuclease and catalytically dead SpCas9 (SpdCas9) as proximal DNA binding protein to enable CjCas9 to cleave the target for gene editing using single stranded DNA oligo templates.

Enhancing the genome editing toolbox: genome wide CRISPR arrayed libraries

CRISPR-Cas9 technology has accelerated biological research becoming routine for many laboratories. It is rapidly replacing conventional gene editing techniques and has high utility for both genome-wide and gene-focussed applications. Here we present the first individually cloned CRISPR-Cas9 genome wide arrayed sgRNA libraries covering 17,166 human and 20,430 mouse genes at a complexity of 34,332 sgRNAs for human and 40,860 sgRNAs for the mouse genome. For flexibility in generating stable cell lines the sgRNAs have been cloned in a lentivirus backbone containing PiggyBac transposase recognition elements together with fluorescent and drug selection markers. Over 95% of tested sgRNA induced specific DNA cleavage as measured by CEL-1 assays. Furthermore, sgRNA targeting GPI anchor protein pathway genes induced loss of function mutations in human and mouse cell lines measured by FLAER labelling. These arrayed libraries offer the prospect for performing screens on individual genes, combinations as well as larger gene sets. They also facilitate rapid deconvolution of signals from genome-wide screens. This set of vectors provide an organized comprehensive gene editing toolbox of considerable scientific value.

Targeted activation of diverse CRISPR-Cas systems for mammalian genome editing via proximal CRISPR targeting

Bacterial CRISPR–Cas systems comprise diverse effector endonucleases with different targeting ranges, specificities and enzymatic properties, but many of them are inactive in mammalian cells and are thus precluded from genome-editing applications. Here we show that the type II-B FnCas9 from Francisella novicida possesses novel properties, but its nuclease function is frequently inhibited at many genomic loci in living human cells. Moreover, we develop a proximal CRISPR (termed proxy-CRISPR) targeting method that restores FnCas9 nuclease activity in a target-specific manner. We further demonstrate that this proxy-CRISPR strategy is applicable to diverse CRISPR–Cas systems, including type II-C Cas9 and type V Cpf1 systems, and can facilitate precise gene editing even between identical genomic sites within the same genome. Our findings provide a novel strategy to enable use of diverse otherwise inactive CRISPR–Cas systems for genome-editing applications and a potential path to modulate the impact of chromatin microenvironments on genome modification.

Bacteria possess a diverse collection of CRISPR-Cas systems but many do not function in mammalian cells, precluding their use in genome editing. Here the authors show that by manipulating local chromatin structures, inhibited Cas9s can have their activity restored in human cells.

Gene editing using ssODNs with engineered endonucleases

Gene editing using engineered endonucleases, such as zinc finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs), and clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 nucleases, requires the creation of a targeted, chromosomal DNA double-stranded break (DSB). In mammalian cells, these DSBs are typically repaired by one of the two major DNA repair pathways: nonhomologous end joining (NHEJ) or homology-directed repair (HDR). NHEJ is an error-prone repair process that can result in a wide range of end-joining events that leads to somewhat random mutations at the site of DSB. HDR is a precise repair pathway that can utilize either an endogenous or exogenous piece of homologous DNA as a template or "donor" for repair. Traditional gene editing via HDR has relied on the co-delivery of a targeted, engineered endonuclease and a circular plasmid donor construct. More recently, it has been shown that single-stranded oligodeoxynucleotides (ssODNs) can also serve as DNA donors and thus obviate the more laborious and time-consuming plasmid vector construction process. Here we describe the use of ssODNs for making defined genome modifications in combination with engineered endonucleases.

Donor plasmid design for codon and single base genome editing using zinc finger nucleases

In recent years, CompoZr zinc finger nuclease (ZFN) technology has matured to the point that a user-defined double strand break (DSB) can be placed at virtually any location in the human genome within 50 bp of a desired site. Such high resolution ZFN engineering is well within the conversion tract limitations demarcated by the mammalian DNA repair machinery, resulting in a nearly universal ability to create point mutations throughout the human genome. Additionally, new architectures for targeted nuclease engineering have been rapidly developed, namely transcription activator like effector nucleases (TALENs) and clustered regularly interspaced short palindromic repeats (CRISPR)/Cas systems, further expanding options for placement of DSBs. This new capability has created a need to explore the practical limitations of delivering plasmid-based information to the sites of chromosomal double strand breaks so that nuclease-donor methods can be widely deployed in fundamental and therapeutic research. In this chapter, we explore a ZFN-compatible donor design in the context of codon changes at an endogenous locus encoding the human RSK2 kinase.

Actin and dynamin2 dynamics and interplay during clathrin-mediated endocytosis

Actin assembly influences the precise temporal and quantitative recruitment of dynamin2 to sites of clathrin-mediated endocytosis.

Clathrin-mediated endocytosis (CME) involves the recruitment of numerous proteins to sites on the plasma membrane with prescribed timing to mediate specific stages of the process. However, how choreographed recruitment and function of specific proteins during CME is achieved remains unclear. Using genome editing to express fluorescent fusion proteins at native levels and live-cell imaging with single-molecule sensitivity, we explored dynamin2 stoichiometry, dynamics, and functional interdependency with actin. Our quantitative analyses revealed heterogeneity in the timing of the early phase of CME, with transient recruitment of 2–4 molecules of dynamin2. In contrast, considerable regularity characterized the final 20 s of CME, during which ∼26 molecules of dynamin2, sufficient to make one ring around the vesicle neck, were typically recruited. Actin assembly generally preceded dynamin2 recruitment during the late phases of CME, and promoted dynamin recruitment. Collectively, our results demonstrate precise temporal and quantitative regulation of the dynamin2 recruitment influenced by actin polymerization.

High-efficiency genome editing via 2A-coupled co-expression of fluorescent proteins and zinc finger nucleases or CRISPR/Cas9 nickase pairs

Targeted endonucleases including zinc finger nucleases (ZFNs) and clustered regularly interspaced short palindromic repeats (CRISPRs)/Cas9 are increasingly being used for genome editing in higher species. We therefore devised a broadly applicable and versatile method for increasing editing efficiencies by these tools. Briefly, 2A peptide-coupled co-expression of fluorescent protein and nuclease was combined with fluorescence-activated cell sorting (FACS) to allow for efficient isolation of cell populations with increasingly higher nuclease expression levels, which translated into increasingly higher genome editing rates. For ZFNs, this approach, combined with delivery of donors as single-stranded oligodeoxynucleotides and nucleases as messenger ribonucleic acid, enabled high knockin efficiencies in demanding applications, including biallelic codon conversion frequencies reaching 30–70% at high transfection efficiencies and ∼2% at low transfection efficiencies, simultaneous homozygous knockin mutation of two genes with ∼1.5% efficiency as well as generation of cell pools with almost complete codon conversion via three consecutive targeting and FACS events. Observed off-target effects were minimal, and when occurring, our data suggest that they may be counteracted by selecting intermediate nuclease levels where off-target mutagenesis is low, but on-target mutagenesis remains relatively high. The method was also applicable to the CRISPR/Cas9 system, including CRISPR/Cas9 mutant nickase pairs, which exhibit low off-target mutagenesis compared to wild-type Cas9.

Derivation and genetic modification of embryonic stem cells from disease-model inbred rat strains

The lack of rat embryonic stem cells (ESCs) and approaches for manipulation of their genomes have restricted the ability to create new genetic models and to explore the function of a single gene in complex diseases in the laboratory rat. The recent breakthrough in isolating germline-competent ESCs from rat and subsequent demonstration of gene knockout has propelled the field forward, but such tools do not yet exist for many disease-model rat strains. Here we derive new ESCs from several commonly used rat models including the Dahl Salt Sensitive (SS), the sequenced Brown Norway (BN), and Fischer (F344) rat and establish the first germline-competent ESCs from a hypertension disease model strain, the Fawn Hooded Hypertensive (FHH) rat. Genetic manipulations including transgenesis mediated by lentivirus, routine homologous recombination, and homologous recombination mediated by zinc-finger nucleases (ZFNs) were performed effectively in FHH rat ESCs. Our results showed these rat ESC lines, isolated from inner cell masses using mechanical splitting, had germline competency; the Pparg gene locus and homologous genomic region to the mouse Rosa26 locus can be targeted effectively in these rat ESCs. Furthermore, our results also demonstrated that ZFNs increased the efficiency of proper homologous recombination in FHH rat ESCs using targeting vectors with short homology arms. These rat ESC lines and advancements in genetic manipulation pave the way to novel genetic approaches in this valuable biomedical model species and for exploration of complex disease in these strains.

Functional genomics, proteomics, and regulatory DNA analysis in isogenic settings using zinc finger nuclease-driven transgenesis into a safe harbor locus in the human genome

Isogenic settings are routine in model organisms, yet remain elusive for genetic experiments on human cells. We describe the use of designed zinc finger nucleases (ZFNs) for efficient transgenesis without drug selection into the PPP1R12C gene, a "safe harbor" locus known as AAVS1. ZFNs enable targeted transgenesis at a frequency of up to 15% following transient transfection of both transformed and primary human cells, including fibroblasts and hES cells. When added to this locus, transgenes such as expression cassettes for shRNAs, small-molecule-responsive cDNA expression cassettes, and reporter constructs, exhibit consistent expression and sustained function over 50 cell generations. By avoiding random integration and drug selection, this method allows bona fide isogenic settings for high-throughput functional genomics, proteomics, and regulatory DNA analysis in essentially any transformed human cell type and in primary cells.

Knockout rats via embryo microinjection of zinc-finger nucleases

The toolbox of rat genetics currently lacks the ability to introduce site-directed, heritable mutations into the genome to create knockout animals. By using engineered zinc-finger nucleases (ZFNs) designed to target an integrated reporter and two endogenous rat genes, Immunoglobulin M (IgM) and Rab38, we demonstrate that a single injection of DNA or messenger RNA encoding ZFNs into the one-cell rat embryo leads to a high frequency of animals carrying 25 to 100% disruption at the target locus. These mutations are faithfully and efficiently transmitted through the germline. Our data demonstrate the feasibility of targeted gene disruption in multiple rat strains within 4 months time, paving the way to a humanized monoclonal antibody platform and additional human disease models.

Credentialing residents for intraoperative cystoscopy

OBJECTIVE

To determine whether incorporation of routine intraoperative cystoscopy for evaluation of potential urinary tract injury into gynecologic residency training provides sufficient experience to justify hospital credentials after graduation.

METHODS

We developed a curriculum to train residents in intraoperative cystoscopic evaluation of potential lower urinary tract injury. Cystoscopy was performed when indicated with hysterectomy and routinely in conjunction with pelvic reconstruction. Faculty members evaluated conceptual and technical proficiency by oral examination and direct observation in the operating room. Once the resident demonstrated a thorough understanding and proficiency in performing intraoperative cystoscopy, a competency certification document was issued by the Program Director. This certification was transmitted to the postresidency hospital credentials committee to justify granting privileges.

RESULTS

Since 1994 over 400 transurethral cystoscopic evaluations have been done in conjunction with major gynecologic abdominal and vaginal surgeries, and since 1997 an additional 50 transvesical microcystoscopies have been done in selected abdominal cases. Twenty-five residency graduates have been certified as fully trained in intraoperative diagnostic cystoscopy. All these graduates have been granted intraoperative cystoscopy privileges at their subsequent hospital practice.

CONCLUSION

Incorporation of cystoscopic urinary tract evaluation into routine gynecologic surgical training is good medical practice and provided a mechanism whereby obstetrics and gynecology residents could obtain intraoperative cystoscopy hospital privileges after graduation. (Obstet Gynecol 2000;96:1014-7.)

The relationship of the in-situ advancing vaginal wall sling to vaginal epithelial inclusion cyst

Epithelial inclusion cyst is an under recognized complication of the in-situ advancing vaginal wall sling. A 63-year-old woman with stage I pelvic organ prolapse and mixed incontinence underwent in-situ sling placement in November 1997. In February 1998 she presented with a painful recurrent inflammatory anterior vaginal wall mass. The mass was cystic and drained spontaneously four times over the period of conservative management. The patient underwent resection of a clinical and pathological vaginal epithelial inclusion cyst in September 1998. At 6-month follow-up the patient remains continent and the cyst has not reformed. The vaginal surgeon should be aware of the potential for epithelial inclusion cyst formation after in-situ sling placement, and actively search for them at postoperative examination.

The relation between stress fractures and bone mineral density: evidence from active-duty Army women

OBJECTIVE

To determine if bone mineral density (BMD) is associated with the probability of stress fractures in premenopausal women.

DESIGN

Case-control study.

SETTING

Large Army post, Fort Lewis, WA.

PARTICIPANTS

Twenty-seven active duty Army women with documented stress fractures within the last 2 years and 158 female controls.

METHODS AND MAIN RESULTS

All subjects were examined and interviewed. BMD of the femoral neck and posteroanterior lumbar spine (L2-L4) was measured using dual energy X-ray absorptiometry. Univariate comparisons revealed no significant differences in BMD of the femoral neck or lumbar spine between groups. Women with stress fractures had a significantly higher exercise intensity (428 vs 292 minutes per week, p<.05) and were more likely to be entry-level enlisted soldiers (63% vs. 44%, p<.05) than those without stress fractures. Multivariate analyses revealed a strong negative association between femoral neck BMD and the probability of stress fractures (lower BMD, higher risk). Exercise intensity and body mass index had a significant positive effect on BMD of the femoral neck and lumbar spine, yet both were associated with an increased probability of stress fractures.

CONCLUSIONS

Femoral neck BMD was significantly associated with the probability of stress fractures. Optimal training programs should balance the beneficial indirect effect of increased exercise (through increased BMD) with its detrimental direct effect on stress fractures.

New fusion protein systems designed to give soluble expression in Escherichia coli

Three native E. coli proteins-NusA, GrpE, and bacterioferritin (BFR)-were studied in fusion proteins expressed in E. coli for their ability to confer solubility on a target insoluble protein at the C-terminus of the fusion protein. These three proteins were chosen based on their favorable cytoplasmic solubility characteristics as predicted by a statistical solubility model for recombinant proteins in E. coli. Modeling predicted the probability of soluble fusion protein expression for the target insoluble protein human interleukin-3 (hIL-3) in the following order: NusA (most soluble), GrpE, BFR, and thioredoxin (least soluble). Expression experiments at 37 degrees C showed that the NusA/hIL-3 fusion protein was expressed almost completely in the soluble fraction, while GrpE/hIL-3 and BFR/hIL-3 exhibited partial solubility at 37 degrees C. Thioredoxin/hIL-3 was expressed almost completely in the insoluble fraction. Fusion proteins consisting of NusA and either bovine growth hormone or human interferon-gamma were also expressed in E. coli at 37 degrees C and again showed that the fusion protein was almost completely soluble. Starting with the NusA/hIL-3 fusion protein with an N-terminal histidine tag, purified hIL-3 with full biological activity was obtained using immobilized metal affinity chromatography, factor Xa protease cleavage, and anion exchange chromatography.

Abnormal eating behaviors in military women

PURPOSE

The purpose of this study was to evaluate the prevalence of abnormal eating behaviors in women on active duty in the Army.

METHODS

A total of 423 female soldiers from the general population on active duty volunteered to participate in this study. They completed the Eating Disorder Inventory (EDI) questionnaire. Each questionnaire was screened and any woman on active duty practicing abnormal eating behaviors (criteria set up by the authors) underwent an interview. A diagnosis, using DSM IV criteria, of one of the following was determined from the interview: 1) No eating disorder, (2) Anorexia nervosa, 3) Bulimia nervosa, 4) binge eating disorder, 5a) Eating disorder NOS, and 5b) Situational eating disorder. A situational eating disorder was defined as any abnormal eating behaviors consistent with an eating disorder NOS that was practiced intermittently and in response to external pressures associated with significant distress, such as military weigh-ins or army physical fitness testing (APFT).

RESULTS

Of the 423 women on active duty who participated, 33.6% (N = 142) met the questionnaire screening criteria for being "at risk" for abnormal eating behaviors and underwent an interview. Of the 142 women interviewed, 33 (8%) women were diagnosed with an eating disorder. The women with eating disorders exercised, felt dissatisfied with their weight, and felt significantly more pressure about their weight than the women without eating disorders. In addition, they also had significantly greater scores on the Drive for Thinness (DT), Bulemia (B), and Body Dissatisfaction (BD) subscales, and the total EDI scores for both the 8 and 11 subscales.

CONCLUSION

In the women on active duty in the Army studied, there was an 8% prevalence of eating disorders.

Clinical management of vulvodynia

Vulvodynia represents a group of vulvar disorders that can be clinically perplexing. Unfortunately, there are no simple tests for its diagnosis. Patients often are reluctant to report vulvar pain. Some are embarrassed to reveal their perceived "sexual dysfunction" caused by dyspareunia. Others have been told in the past "It's all in you head," or "It's just a yeast infection." Most patients with vulvodynia are seen by multiple practitioners and are placed on a variety of treatments before a correct diagnosis is made. All too often, these treatments are not only ineffective but also damaging. Careful clinical investigation is required for the correct diagnosis and treatment of vulvodynia (Figure 2).

Decline in bone mineral density with stress fractures in a woman on depot medroxyprogesterone acetate. A case report

BACKGROUND

Depot medroxyprogesterone acetate is a popular contraceptive among young, physically active women. However, its administration has been linked to a relative decrease in estrogen levels. Since bone resorption is accelerated during hypoestrogenic states, there has been growing concern about the potential development of osteoporosis and fractures with the use of this contraceptive method.

CASE

A physically active, 33-year-old woman demonstrated a 12.4% drop in femoral neck bone mineral density (BMD), 6.4% drop in lumbar BMD and 0.8% drop in total BMD with the subsequent development of a tibial stress fracture while on depot medroxyprogesterone acetate. Bone mineralization rapidly improved, and the stress fracture resolved with discontinuation of the medication.

CONCLUSION

The long-term effects of depot medroxyprogesterone acetate on bone mineralization in physically active women should be evaluated more thoroughly.

Enhancing advanced surgical laparoscopy. Combined, routine use of microlaparoscopes and macrolaparoscopes

OBJECTIVE

To describe a variety of techniques for using the microlaparoscope in conjunction with a standard-sized laparoscope for simplifying and enhancing advanced laparoscopic surgery.

STUDY DESIGN

Descriptive study of microlaparoscopic techniques for enhancing macrolaparoscopic procedures.

RESULTS

The microlaparoscope facilitates macrolaparoscopy by permitting: (1) specimen removal and use of 10-mm instruments without secondary, large ports; (2) performance of laparoscopic vaginal hysterectomy with the endoscopic stapler using only one 12-mm port; (3) lysis of difficult pelvic and periumbilical adhesions; (4) enhancement of visual access to difficult operative sites; (5) closure of large umbilical and secondary port sites under direct monitoring; (6) visualization from the left upper quadrant when umbilical adhesions are suspected; and (7) use as the initial entry laparoscope when extensive surgery is not anticipated.

CONCLUSION

The routine, combined use of the microlaparoscope and 10-mm laparoscope significantly expands the capabilities of the advanced laparoscopic surgeon. Procedures are simplified, facilitated and made less invasive.

Recombinant production and purification of novel antisense antimicrobial peptide in Escherichia coli

A fusion protein was genetically engineered that contains an antimicrobial peptide, designated P2, at its carboxy terminus and bovine prochymosin at its amino terminus. Bovine prochymosin was chosen as the fusion partner because of its complete insolubility in Escherichia coli, a property utilized to protect the cells from the toxic effects of the antimicrobial peptide. This fusion protein was purified by centrifugation as an insoluble inclusion body. A methionine linker between prochymosin and the P2 peptide enabled P2 to be released by digestion with cyanogen bromide. Cation exchange HPLC followed by reversed-phase HPLC were used to purify the P2 peptide. The recombinant P2 peptide's molecular mass was confirmed by mass spectrometry to within 0.1% of the theoretical value (2480.9 Da), and the antimicrobial activity of the purified recombinant P2 against E. coli D31 was determined to be identical to that of the chemically synthesized peptide (minimal inhibitory concentration of 5 mg/mL). Although the yield of the fusion protein after expression by the cells was high (16% of the total cell protein), the percentage recovery of the P2 peptide in the inclusion bodies was relatively low, which appears to be due to losses in the cyanogen bromide digestion step.

Behavioral treatment of exercise-induced urinary incontinence among female soldiers

One-third of 450 female soldiers surveyed indicated that they experienced problematic urinary incontinence during exercise and field training activities. The other crucial finding of this survey was probably that 13.3% of the respondents restricted fluids significantly while participating in field exercises. Although only 5.3% of respondents felt that their urine leakage had a significant impact on their regular duties, it is obvious that many more are sufficiently worried about leakage to put themselves at significant risk for dehydration-related injuries. This study tested whether behavioral interventions effective among older people could help younger soldiers. Thirty-nine female soldiers reporting exercise-induced urinary incontinence underwent urodynamic assessments of bladder capacity, urethral closure pressure, and detrusor contraction pressures as well as a symptom questionnaire before and after therapy. They were stratified by diagnosis of physical stress incontinence or mixed urge/stress incontinence and randomized into two groups. Twenty-three participants performed pelvic muscle exercises with urethral biofeedback for 8 weeks, and 16 participants performed pelvic muscle exercises alone. Patient reports as well as the post-treatment examinations indicated that all subjects improved significantly. Only five subjects in the biofeedback/exercise and three in the exercise-only group desired further treatment. All subjects initially diagnosed with detrusor dysfunction had normal readings at the end of the study. Thus, behavioral treatments can be effective against exercise-induced urinary incontinence among most female soldiers.

A microlaparoscopic technique for Pomeroy tubal ligation

OBJECTIVE

To evaluate the efficacy of performing Pomeroy tubal ligation using microlaparoscopic techniques.

METHODS

Thirty-eight consecutive women desiring permanent sterilization underwent laparoscopic Pomeroy tubal ligation using small (2 or 5 mm) transumbilical laparoscopes and secondary midline sites (5 mm and 14 gauge). The procedures were performed under general anesthesia (n = 28) or local anesthesia with conscious sedation (n = 10).

RESULTS

The mean operative time +/- standard deviation (SD) in minutes was 33.0 +/- 10.3. The mean recovery time +/- SD in minutes was 104.3 +/- 41.6. There were no operative complications, and no cases required conversion from the microlaparoscopic technique to a traditional method.

CONCLUSION

The results of this study indicate that the Pomeroy tubal ligation may be performed using microlaparoscopic techniques. Furthermore, in selected cases, this technique can be performed under local anesthesia in an outpatient setting.

Long-term results of laparoscopic Burch urethropexy

STUDY OBJECTIVE

To evaluate the long-term efficacy of laparoscopic Burch urethropexy.

DESIGN

Pilot study.

SETTING

Private practice.

PATIENTS

Thirty-five consecutive women (average age 45.5 yrs, average parity 2.3, average weight 67.7 kg) treated for genuine stress incontinence between May 1992 and July 1994.

INTERVENTIONS

Urethropexy was performed with curved needle suturing in 7 women, straight needle suturing in 5, and Stamey needle suturing in 23. Twenty-five (71.4%) patients had concomitant pelvic surgery.

MEASUREMENTS AND MAIN RESULTS

Wilcoxon two-sample, chi2, and Fisher's exact tests were performed to determine which variables were significantly associated with surgical success. Average operating time was 190 minutes, hospitalization 24 hours, and catheterization 5 days. The cure rate of stress incontinence was 89% 3 months and 86% 1 year after surgery. At average follow-up of 34 months, only 68.6% of patients reported complete or almost complete cure, 11.4% were improved, and 20% were complete failures. The only operative variable approaching statistical significance for predicting surgical success was type of suture needle (p = 0.07), with the Stamey needle group having the highest cure rate. Women who were cured or almost cured had a significantly shorter follow-up than those who were improved or failures (p = 0.001).

CONCLUSION

The success rate of laparoscopic Burch urethropexy compares with that of open Burch procedure at 1 year, but drops considerably thereafter.

Long-Term Results of Laparoscopic Burch Urethropexy

We evaluated the long-term efficacy of laparoscopic Burch urethropexy performed in 35 consecutive women (average age 45.5 yrs, average weight 67.7 kg, average parity 2.3) between May 1992 and July 1994. Preoperative evaluations included cotton swab testing, urinalysis, dynamic urethrocystoscopy, and multichannel urodynamic testing. All subjects had genuine stress incontinence and a positive cotton swab test. Urethropexy was performed with curved needle suturing in 7 women, straight needle suturing in 5, and Stamey needle suturing in 23. Outcome variables were operative time, concomitant surgery, suture needle, length of hospital stay, need for catheterization, and subjective success. Women were divided into groups based on surgical success. Wilcoxon two-sample, chi2, and Fisher's exact tests were used to determine which variables were significantly associated with surgical success. Twenty-five women (71.4%) had concomitant pelvic surgery at the time of urethropexy. Average time of surgery was 190 minutes, length of stay 1 day, and length of time for catheterization 5 days. The cure rate of stress incontinence was 89% at 3 months and 86% at 1 year. At an average follow-up of 30 months, only 68.6% of women reported complete or almost complete cure, 11.4% were improved, and 20% were complete failures. The only variable approaching statistical significance for predicting surgical success was type of suture needle used (p = 0.07), with the Stamey needle group having the highest cure rate. The success rate of laparoscopic Burch urethropexy compares with that of open Burch procedure at 1 year but drops considerably thereafter.

Uterine prolapse after laparoscopic uterosacral transection in nulliparous airborne trainees. A report of three cases

BACKGROUND

Laparoscopic uterine nerve ablation (LUNA) has become a common alternative therapy for refractory dysmenorrhea. Few long-term complications have been reported.

CASES

Severe uterine prolapse was diagnosed in three young female soldiers during or after the rigors of airborne training. All three had previously undergone LUNA procedures. No other risk factors for uterine prolapse could be identified in these cases.

CONCLUSION

The etiology of uterine prolapse is complex, and although no conclusions as to cause and effect can be made, these cases suggest that LUNA should be performed with caution on women whose occupation or life-style is associated with heavy physical labor or exercises producing marked increases in intraabdominal pressure.

Purification of (+)-delta-cadinene synthase, a sesquiterpene cyclase from bacteria-inoculated cotton foliar tissue

A sesquiterpene cyclase whose activity is induced in a glandless, bacterial blight-resistant line of cotton (Gossypium hirsutum L.) catalyses the conversion of (E,E)-farnesyl diphosphate to (+)-delta-cadinene. This enzyme was purified by a combination of salt-induced phase separation, hydroxylapatite fractionation, hydrophobic interaction and strong anion-exchange chromatography, and denaturing polyacrylamide gel electrophoresis, followed by renaturation with Tween 80. The purified enzyme has a molecular weight of 64-65 kDa, and exhibited a single silver-staining band following electrophoresis in analytical denaturing polyacrylamide gels. Amino acid sequences of three tryptic peptides from the enzyme have been determined and are similar to known sequences in other terpene cyclases from plants.

Lactation from axillary breast tissue in the absence of a supernumerary nipple. A case report

A case of lactation apparently from axillary supernumerary breast tissue was observed in a lactating woman. The tissue showed histologic features typical of both normal glands of lactation and apocrine sweat glands, and the fluid showed evidence of milk production. The supernumerary breast tissue was not associated with a nipple. Renal and skeletal anomalies were also noted.

Laparoscopically assisted vaginal hysterectomy as definitive therapy for stage III and IV endometriosis

Operative laparoscopy combined with vaginal hysterectomy and salpingo-oophorectomy was used to treat advanced endometriosis in 40 of 46 patients. This treatment plan was abandoned in favor of laparotomy in six patients. Of the 40 patients successfully treated by laparoscopically assisted vaginal hysterectomy, 39 are completely free of symptoms. Major complications, including blood loss requiring transfusion and injury to the ureter or bowel, were sustained at acceptable rates. No serious infections occurred. The mean operating time was 191 minutes. Laparoscopically assisted vaginal hysterectomy and removal of all ovarian tissue combined with excision of all endometriosis may be used as definitive therapy for advanced endometriosis. The major complications associated with surgical therapy for high-stage endometriosis are encountered; therefore, laparoscopic treatment requires advanced laparoscopic surgical skills.

Clinical characteristics of adolescent endometriosis

Our study objective was to describe the appearance, stage, and treatment of endometriosis in adolescents undergoing laparoscopic treatment of severe dysmenorrhea and endometriosis. We designed a retrospective analysis of adolescents with endometriosis whose primary symptom was severe dysmenorrhea. We studied patients in a private practice associated with a residency program. Forty-nine adolescents with histologically confirmed endometriosis underwent laparoscopy. Thirty-six of these patients (mean age, 16.6 +/- 1.4 years; range, 13-20 years) presented with severe dysmenorrhea in a non-emergency state and were refractory to prior therapy. All patients underwent laparoscopic surgery. We classified endometriosis implants as typical implants, red lesions, and occult lesions in thirty-six adolescents. We excised infiltrating lesions (defined as implants penetrating greater than 3-5 mm) and vaporized or coagulated superficial lesions (defined as surface implants or those penetrating < 3 mm). All adolescents underwent postsurgical ovulation suppression with a daily birth control pill. The need for reoperation at any time or the use of GnRH analogs, Danazol, or large doses of progestins served to indicate treatment failure. The presence or absence of red lesions was recorded in this group and compared to the presence or absence of such lesions in an older population of patients undergoing definitive therapy for endometriosis during the same time period. Our results showed that red lesions are the predominant implant type in adolescents. Adolescents with cyclic pain and those who complain of abdominal pain, nausea, constipation, and diarrhea, during menses had the largest proportion of red lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

Colposcopic examination of the vagina

Examination of the vagina must include assessment of the minor vestibular glands and urethral meatus. Vaginal mucosal lesions related to papillomavirus infection and neoplasia are best discovered by the use of acetic acid wash followed by the application of Monsel's solution.

Transabdominal laser colpotomy

Transabdominal laser colpotomy was performed on 26 women for the removal of sizable pathologic specimens obtained through extensive operative laparoscopy. We used CO2 lasers operated at 10-30 W with a continuous wave. The colpotomy incision was cut across ring forceps that were then used to retrieve and remove the specimens vaginally under laparoscopic control. Colpotomy was found to be safe and not to increase morbidity in extensive laparoscopy.

Excision of pelvic endometriosis with the carbon dioxide laser laparoscope

Laparoscopic vaporization of peritoneal endometriosis has been reported to relieve pain and enhance fertility. However, vaporization of endometriosis, particularly large plaques and hemorrhagic areas, is associated with significant amounts of carbon deposition in the desicated tissues. Further, it is difficult to ascertain complete removal of disease in some areas. In this study, 66 patients were treated by excision of peritoneal and/or ovarian endometriosis with the carbon dioxide laser via laparoscopy. Using excisional techniques, we were able to visualize the extent of peritoneal penetration and subperitoneal spread of endometriotic nodules. Further, we obtained histologic confirmation of the disease process in all patients. No patient received postoperative hormonal therapy during follow-up. Follow-up evaluation of these patients revealed relief of the painful symptoms of endometriosis. No long-term complications were encountered.

Management of endometriosis and its associated adhesions with the CO2 laser laparoscope

One hundred fifty-eight patients with endometriosis were treated with the carbon dioxide laser laparoscope and followed for 15 months. The revised American Fertility Society classification of endometriosis was used to stage the disease. The median revised American Fertility Society points per patient was 29.4. Removal of adhesions, periureteral endometriosis, and superficial bowel endometriosis was accomplished. Complications consisted of bleeding, extravasation of fluid, and uterine and bladder puncture. No serious complications requiring laparotomy were encountered. Significant relief of dysmenorrhea and dyspareunia as well as enhanced fertility was achieved. Second-look laparoscopy confirmed efficient removal of endometriosis. Pain relief and pregnancy data are presented. Endometriosis and its related adhesions can be removed precisely and relatively bloodlessly with the carbon dioxide laser laparoscope. Expertise in advanced laparoscopy and a thorough knowledge of use of the carbon dioxide laser and its bioeffects are prerequisites to performing this procedure.

Management of Bartholin duct cysts with the carbon dioxide laser

Fourteen women with Bartholin duct cysts were treated by creating a neostoma with the carbon dioxide laser at the time of cyst drainage. No catheters, packs, or other materials were left in the treated gland. All but one patient were treated in the author's office under local anesthesia. All patients were managed using the same operative technique. Twelve of the 14 patients required only one treatment. One patient required three operations and another two procedures. General anesthesia was necessary in only one patient. All patients conformed to long-term follow-up. All patients are now free of disease and apparently have normal glandular function. It is concluded that this technique, when used in selected patients, may offer benefits over conventional approaches and has little or no morbidity.

Coronary artery disease in diabetic and nondiabetic patients: a clinical and angiographic comparison

A comparison of data from 58 diabetic and 58 nondiabetic patients with arteriographic evidence of coronary artery disease showed that diabetic patients had a significantly greater frequency of major stenoses in the intermediate coronary artery segments but no significant differences in the proximal or distal segments. Thus, the diabetic patients did have more severe coronary disease, but the diabetic group did not have "more distal" disease as represented by the number of major or minor lesions in the distal segments. The diabetic patients had a significantly greater frequency of electrocardiographic intraventricular conduction defects and manifestations of left ventricular dysfunction. There was no significant difference in the severity of coronary artery disease between the diabetic patients with manifestations of myocardial decompensation and the diabetic patients without such manifestations, suggesting that the increased frequency of myocardial dysfunction in diabetic patients may be related to factors other than the greater severity of coronary artery disease.

Capillary hemangioma of the cervix and vagina: management with carbon dioxide laser

A hemangioma involving the cervix and vagina was treated successfully with the carbon dioxide laser. This is the second such instance reported. The world literature has been reviewed, and the operation described in detail. This benign neoplasm can be managed conservatively in young women who desire preservation of their childbearing ability.

Congenital pulmonary atresia: photographic subtraction as an aid in recognizing hypoplastic pulmonary arteries

Photographic subtraction is a valuable adjunct for studying patients with pulmonary atresia, ventricular septal defect, and systemic pulmonary collateral vessels. In about 9% of 282 patients, it helped identify the true central pulmonary arteries and whether or not they were confluent. This technique, used retrospectively in evaluating patients previously considered inoperable, has permitted recall of several patients for repeat study and probable corrective or palliative surgery.

Double-outlet right ventricle. Anatomic and angiocardiographic correlations

A series of 72 patients with proved double-outlet right ventricle was studied with reference to the ability of angiocardiography to determine the location of a ventricular septal defect when it was associated with various great-artery relationships. Only 2 of the 72 patients had an intact ventricular septum. The other 70 patients had 16 possible anatomic variations based on four positions of the ventricular septal defect (subaortic, subpulmonary, subaortic and subpulmonary, and remote type) and four great-artery relationships (normal, side by side, dextromalposition, and levomalposition). Using the hemodynamic information regarding systemic and pulmonary arterial saturations, combined with biplane angiocardiographic data from the right ventricle (and if possible with left ventriculography), one can predict the location of ventricular septal defect. Because the different types of double-outlet right ventricle have different surgical approaches, this information can be important to the surgeon.

Congenital pulmonary atresia with ventricular septal defect: angiographic and surgical correlates

Of 181 patients with severe congenital pulmonary atresia and ventricular septal defect or "type IV truncus" (an obsolete term), all but 11% had true central pulmonary arteries. These arteries were demonstrable by large serial biplane angiograms using multiple selective injections into collateral vessels, frequent photographic subtraction, and occasional pulmonary vein-wedge angiograms. These techniques are extremely important for accurate diagnosis and in planning corrective or palliative surgery, which was done in 77% of patients with pulmonary arteries.

Clinical, angiographic, and hemodynamic assessment of late results after Mustard operation

Since 1974, late results of the Mustard procedure for correcting complete transposition of the great arteries have been evaluated by cardiac catheterization, electrocardiography, roentgenography, history, and physical examination of 48 Mayo Clinic patients. Of these, 15 were studied 1 month to 2 years postoperatively because of clinical deterioration. The other 33 had been asymptomatic but were asked to return for hemodynamic reevaluation one-half to 11 years postoperatively. Of the asymptomatic group, 19 underwent exercise electrocardiography prior to catheterization and eight performed supine exercise during catheterization. Cardiac catheterization proved the most effective mode of study. Significant cardiovascular abnormalities (caval obstruction, residual pulmonary stenosis, etc.) were found in 35 of the 47 patients--including 20 of the 33 who were asymptomatic. Eight of the symptomatic group and three of the others have died since this restudy. These poor results warrant renewed effort to devise better methods for correcting complete transposition,

Radiographic assessment of leaflet motion of Gore-Tex laminate trileaflet valves and Hancock xenograft in tricuspid position of dogs

Six samples of various thicknessess of Gore-Tex compounds were fashioned into trileaflet valves. A radiopaque marker was placed on the center of the free margin of each cusp, and the prostheses were implanted in the tricuspid position of dogs. Two Hancock valves were studied for comparison. Catheterization revealed that the hemodynamic function was normal in all valves tested. High-speed radiography permitted analysis of leaflet movement throughout the cardiac cycle. Of the six Gore-Tex valves, five opened completely. The cusps of these five valves were fabricated from 4, 6, 8, 10, and 12 layers of Gore-Tex film. The remaining valve, which was fabricated from 15 layers of Gore-Tex film, and both porcine xenograft aortic valves did not open completely. We postulate that the laminates of 12 layers or less of Gore-Tex film are suitable for further study to evaluate their potential applicability in trileaflet cardiac valve prostheses.

A criss-cross heart. Detailed anatomic description and discussion of morphogenesis

Hearts with criss-cross atrioventricular connections are rare. Reports in the literature describe great anatomic variations with regard to the atrioventricular connections, spatial relationships of the ventricles, and connections and spatial relationships of the great arteries. In the example described in this report, the basic anatomic picture was that of transposition of the great arteries, but the criss-cross atrioventricular valves had resulted in atrioventricular discordance; hemodynamically, therefore, the situation resembled congenitally corrected transposition. One hypothesis for this anatomic configuration is that pronounced counterclockwise rotation (as viewed from below) brought the ventricular septum into a frontal plane and altered the respective positions of the pulmonary and aortic valves from those usually seen in congenitally corrected transposition and thereby resulted in crossed atrioventricular connections. An alternative hypothesis is that in this case one of the atrioventricular valves (the anteriorly positioned valve) may represent an anomalous communication that developed early in embryogenesis and connected the left atrial appendage to the right ventricular infundibulum.

Systemic collateral and pulmonary artery stenosis in patients with congenital pulmonary valve atresia and ventricular septal defect

Angiograms of 30 patients with congenital pulmonary valve atresia, ventricular septal defect, and large systemic-pulmonary collateral arteries (SPCAs) were evaluated. All had aortography, 28 had SPCA arteriography, and 26 had right ventriculography. Seventeen (65%) of 26 patients had a right ventricular infundibulum, 23 (77%) had a pulmonary artery confluence, and five of the nine patients without a right ventricular infundibulum had a confluence. Sixty-six SPCAs of aortic origin were seen; 28 (42%) had narrowing and 21 patients (70%) had one or more narrowed SPCAs. Five patients had collaterals from internal mammary, subclavian or innominate arteries. Fourteen (47%) had hilar pulmonary artery stenosis. Of these 14 patients mild peripheral stenosis was demonstrated in five. Right aortic arch was present in 15 patients (50%). Complete angiographic delineation of pulmonary vasculature is an essential procedure for preoperative detection of pulmonary and SPCA stenoses in these patients.