Open laparoscopy. Commentary

Open laparoscopy has been receiving increased attention in the US and internationally. However, opinions differ on its appropriate role in laparoscopy services. In the US some surgeons remain comfortable using closed laparoscopy for all patients, including some who have had previous abdominal surgery. Some centers are using more open procedures, especially for training programs and for cases where open laparoscopy may be indicated, as described by Dr. Hasson in this "Bulletin." Others have converted to performing all laparoscopy by the open technique. The Planned Parenthood Federation of America encourages minilaparotomy and open laparoscopy for tubal occlusion n its facilities because of the greater inherent potential for patient safety with these approaches. AVS has not provided open laparoscopy equipment to international programs, although some projects have used an open technique. Neither the World Federation of Health Agencies for the Advancement of Voluntary Surgical Contraception nor the AVS Science Committee has addressed the role of open laparoscopy in international programs. This is due in part to insufficient worldwide experience in open laparoscopy. However, this does not preclude AVS from providing such equipment for open laparoscopy in the future. In the US approximately 300-500 Hasson cannulas have been commercially distributed annually for the past 4-5 years. About 2000 may be currently in use in the US. Therefore, among the 6915 hospitals registered with the American Hospital Association in 1982, a substantial proportion may now provide access to open laparoscopy equipment. Studies in the US are not yet available to fully assess the safety of open laparoscopy. However, general comparisons of complication rates for open and closed laparoscopy may not be appropriate since many surgeons reserve the more complicated cases for open laparoscopy.     

Individual differences in the elevated plus-maze and the forced swim test

The elevated plus-maze is an apparatus composed of enclosed and open (elevated) arms and time spent in the open arms by a rat can be increased/decreased by anxiolytic/anxiogenic agents. In the forced swim test, floating behavior is used as an index of behavioral despair and can be decreased by antidepressant agents. As the comorbidity between anxiety and depression is a remarkable issue in human behavioral disorders, a possible relationship between the behaviors seen in the cited tests is of great relevance. In the present study, fifty-four male rats (Rattus norvegicus) were submitted to a plus-maze session and to a 2-day forced swim protocol. According to their time in the open arms, they were divided into three groups: Low Open, Medium Open and High Open. Some plus-maze measures were found to be coherent with time in the open arms and are suggested to also be reliable anxiety indexes. In the forced swim test, the Low Open group showed decreases in floating duration from forced swim Session 1 to Session 2, an alteration opposite to that observed in the other groups (particularly, the Medium Open group). The Low Open group also showed increases in floating latency, again in sharp contrast with the alteration found in the other groups. Accordingly, positive and negative correlation were found between time in the open arms and floating duration and latency, respectively. Results are compared to previous studies and mediation of the effect by reactivity to aversive stimulation or alterations induced by open arm exposure is discussed.     

Human optokinetic responses under quasi-open and closed loop conditions

The human optokinetic response to a horizontally moving striped pattern surrounding the subject was investigated under quasi-open and closed loop conditions. Open loop conditions were produced by the addition of an external signal from measured slow phase eye velocity to stripe velocity. A comparison of open and closed loop responses to step and sinusoidal changes of stripe velocity indicates that the central nervous system controlling slow phase optokinetic following can be described as a simple first order lag (Ka/(s+a)) where K is 4.7 and the time constant, 1/a, is 1.25 s.     

Revisiting the concept of lineage in prokaryotes: a phylogenetic perspective

Mutation and lateral transfer are two categories of processes generating genetic diversity in prokaryotic genomes. Their relative importance varies between lineages, yet both are complementary rather than independent, separable evolutionary forces. The replication process inevitably merges together their effects on the genome. We develop the concept of “open lineages” to characterize evolutionary lineages that over time accumulate more changes in their genomes by lateral transfer than by mutation. They contrast with “closed lineages,” in which most of the changes are caused by mutation. Open and closed lineages are interspersed along the branches of any tree of prokaryotes. This patchy distribution conflicts with the basic assumptions of traditional phylogenetic approaches. As a result, a tree representation including both open and closed lineages is a misrepresentation. The evolution of all prokaryotic lineages cannot be studied under a single model unless new phylogenetic approaches that are more pluralistic about lineage evolution are designed.     

Simultaneous high-throughput recombinational cloning of open reading frames in closed and open configurations

Comprehensive open reading frame (ORF) clone collections, ORFeomes, are key components of functional genomics projects. When recombinational cloning systems are used to capture ORFs in master clones, these DNA sequences can be easily transferred into a variety of expression plasmids, each designed for a specific assay. Depending on downstream applications, an ORF is cloned either with or without a stop codon at its original position, referred to as closed or open configuration, respectively. The former is preferred when the encoded protein is produced in its native form or with an amino-terminal tag; the latter is obligatory when the protein is produced as a fusion with a carboxyl-terminal tag. We developed a streamlined protocol for high-throughput, simultaneous cloning of both open and closed ORF entry clones with the Gateway recombinational cloning system. The protocol is straightforward to set up in large-scale ORF cloning projects, and is cost-effective, because the initial ORF amplification and the cloning in a pDONR vector are performed only once to obtain the two ORF configurations. We illustrated its implementation for the isolation and validation of 346 Arabidopsis ORF entry clones.     

Vitrification in Open and Closed Carriers at Different Cell Stages: Assessment of Embryo Survival,Development, DNA Integrity and Stability during Vapor Phase Storage for Transport

Background  

High cooling rates with vitrification can be achieved through the use of carriers that allow cryopreservation in fluid volumes < one μl. Open carriers allow direct contact of embryos with liquid nitrogen (LN2) whereas closed carrier systems sequester the embryo within a sealed system during immersion in LN2. The use of closed systems may be preferable to reduce the possibility of cross-contamination. In the present study, we compare open and closed carriers for vitrification of embryos. We also examine their ability to retain embryo viability during vapor phase transport.     

Differing characteristics in 100 consecutive secondary rhinoplasty patients following closed versus open surgical approaches

Open rhinoplasty has unquestionably become more popular during the past two decades because of the putative diagnostic and technical advantages that direct transcolumellar access offers. To test the hypothesis that patients initially treated by the opened or closed approaches differed in the secondary deformities that developed, a retrospective study was conducted of 100 consecutive secondary rhinoplasty patients (66 women and 34 men) operated on by the author before February of 1998. Sixty-four percent had previously undergone closed rhinoplasties and 36 had undergone open rhinoplasties; the incidence of prior open rhinoplasty had increased steadily over the survey years, from 21 percent in 1996 to more than 50 percent in 1998, 1999, and 2000 (p < 0.05). The data generated indicate the following. First, the open rhinoplasty patients had undergone more operations (3.1 versus 1.2) and had more presenting complaints (5.8 versus 2.6) than the closed rhinoplasty patients. Second, although the most common presenting complaint among prior closed rhinoplasty patients was an overresected dorsum (50 percent) or tip (33 percent) or internal valvular obstruction (42 percent), prior open rhinoplasty patients complained more frequently than the closed rhinoplasty patients of these problems and also external valvular obstruction (50 percent, p < 0.0001), short nose (39 percent, p < 0.001), wide columella (36 percent, p < 0.001), narrow nose (31 percent, p < 0.001), columellar scar (25 percent, p < 0.001), and symptomatic columellar struts (19 percent, p < 0.001). Only excessive nasal length was more prevalent among closed rhinoplasty patients (20 percent, p < 0.01). Third, ranking of deformities differed significantly (p < 0.0001) between the two groups, so that complaints related to the nostrils, nasal tip, nasal length, or columella were more common among the open rhinoplasty patients than among those previously treated endonasally. Fourth, the relative frequencies of surgical complaints also differed: whereas patients previously treated endonasally were 6.7 times more likely to complain of long noses, patients previously treated by open rhinoplasty complained more frequently of the following: excessive columellar width (open approach, 36 percent of patients; closed approach, none), hard columellar struts (open approach, 19 percent of patients; closed approach, none), external valvular obstruction (4.5 times as frequent with the open approach as it was with the closed approach), alar/nostril distortion (four times as frequent), and narrow nose (3.9 times). Although the most common complaints among all postrhinoplasty patients remain the overresected dorsum, tip, or (internal valvular) airway obstruction, the author's data suggest that patients previously treated by the open approach are more likely to have postsurgical deformities and complaints referable to those anatomic structures most easily reached by transcolumellar exposure and to techniques that can be performed more readily or aggressively through that access route.     

The blind search for the closed states of hinge-bending proteins

The hinge-bending proteins provide the most pronounced example of the large-amplitude slow motions in a number of proteins, which are critical for their functioning. They are often used as the test ground for developing novel approaches to the simulation of slow protein dynamics. In the present study, we present the algorithm, which allows physically-consistent simulations of slow protein dynamics in globular proteins. Our algorithm is based on the hierarchical clustering of the correlation patterns (HCCP) technique of domain identification, which allows subdividing the protein into the hierarchy of the rigid-body-like clusters. The clusters are allowed to rotate relative to one another on the automatically identified hinges. The clusters are found in the course of automated, objective and well-tested procedure. In the present communication, our technique is applied to 10 hinge-bending proteins. For each of the proteins, we performed the blind search for the closed conformation, staring from the open one. Resulting closed conformations are compared with the closed states observed in crystallographic structures. It is shown that our technique produces realistic closed conformations for 8 out of 10 studied proteins. This demonstrates that HCCP technique can be used for finding alternative protein conformations and for sampling the slow motions in proteins.     

Glycosylation of human LDL and its metabolism in human skin fibroblasts

Extrachromosomal DNA of heterogeneous size has been isolated from bursal lymphocytes and splenocytes of five week old chickens, and from splenocytes of mice. This DNA contains covalently closed circles, open circles, and open circles with tails. Open circular molecules with and without tails are more frequent than covalently closed species, and the total number of small circular DNA molecules per cell is in the range of 100–200 copies.     

A model of the gating of ion channels

The gating of ion channels in biological membranes has usually been described in terms of Markov transitions between a few discrete open or closed states. Such models predict that the distributions of open and closed durations decay as a sum of exponential terms. Recent experimental data have indicated that certain channels are not easily described by these models. We show that distributions of open and closed times similar to those seen experimentally are predicted by a model that involves only one open and closed state but that assumes the activation energy of the gating process to be stochastic. This model involves only a few parameters and these have direct physical interpretations. Measurements of the correlation between the durations of successive open or closed events is shown to provide an experimental method for distinguishing between this and other models.     

Coupled and uncoupled Markov systems: a possible way to distinguish between them

The conditional distributions of openings and closings are computed for Markov schemes with two open and two closed states and with different pathways connecting the open and closed aggregates. The computation is performed for uncoupled schemes by directly applying the probability laws and by using a convolution algorithm for coupled schemes. The results show that, for coupled schemes, conditional distributions can be nonmonotonic functions of the dwell time duration. Simulations, illustrating how the difference between coupled and uncoupled models can be detected, are also reported.     

A fresh look at the open rhinoplasty technique

Use of the open rhinoplasty technique (ORT) in certain nasal and septal deformities has proven to be an invaluable asset in the rhinoplasty armamentarium of the authors. Primarily owing to the markedly increased exposure with this technique, more accurate assessment of the deformities is possible and additional or improved surgical maneuvers become available, particularly in the tip. Sculpting the entire cartilaginous and/or bony vault, as well as correcting difficult septal malalignments, can be carried out under better direct vision with greater precision, accuracy, and predictability. This has led to improved and more consistent final results. Previous criticisms of unsightly columellar scars have been virtually eliminated through the use of improved surgical techniques and simple magnification. Overall, open rhinoplasty technique can provide many distinct advantages in certain nasal deformities with no real disadvantages over conventional closed techniques.     

Use of laparoscopy in pediatric urology

The goal of laparoscopy is to minimize patient morbidity while maintaining successful outcomes. The use of laparoscopy in urology has grown significantly over the past 30 years. Its use has been slower to gain acceptance in pediatrics than in the adult population. Laparoscopic orchidopexies and nephrectomies are commonly performed and have become widely accepted as alternatives to open surgery, if not the gold standard. The more technically demanding procedures, such as laparoscopic pyeloplasty, laparoscopic-assisted bladder reconstruction, and laparoscopic ureteral reimplantation, tend to be performed at selected centers and have yet to achieve widespread acceptance. As laparoscopy is applied more widely in pediatric urology, its potential benefits and drawbacks will be clarified.     

Open otoplasty

The fundamental challenge in correcting protruding ears is to create an anthelix fold that has a natural appearance: evenly rounded and without sharp edges. More or less favorable results have been reached using different methods of excision, superficial incision, suturing, and cartilage tubing. A good method must also fulfill some additional requirements. It must be simple and not too time-consuming. In addition, it should be comfortable for the patient, easily adapted to different anatomical conditions, and have a minimal recurrence rate. The following technique to be described has been used by the author for more than 30 years. He has operated on approximately 870 patients with the open technique. In this article, the last 80 consecutive patients are reported after their follow-up visits. Over the years, the technique has been modified in some details. The auricular cartilage is incised along the lateral border of the anthelical fold. The entire anterior surface of the anthelix is dissected free and abraded. The cartilage bends backward, and a natural anthelix fold is created.     

Two-dimensional kinetic analysis suggests nonsequential gating of mechanosensitive channels in Xenopus oocytes

Xenopus oocytes express mechanosensitive (MS(XO)) channels that can be studied in excised patches of membrane with the patch-clamp technique. This study examines the steady-state kinetic gating properties of MS(XO) channels using detailed single-channel analysis. The open and closed one-dimensional dwell-time distributions were described by the sums of 2-3 open and 5-7 closed exponential components, respectively, indicating that the channels enter at least 2-3 open and 5-7 closed kinetic states during gating. Dependency plots revealed that the durations of adjacent open and closed intervals were correlated, indicating two or more gateway states in the gating mechanism for MS channels. Maximum likelihood fitting of two-dimensional dwell-time distributions to both generic and specific models was used to examine gating mechanism and rank models. A kinetic scheme with five closed and five open states, in which each closed state could make a direct transition to an open state (two-tiered model) could account for the major features of the single-channel data. Two-tiered models that allowed direct transitions to subconductance open states in addition to the fully open state were also consistent with multiple gateway states. Thus, the gating mechanism of MS(XO) channels differs from the sequential (linear) gating mechanisms considered for MS channels in bacteria, chick skeletal muscle, and Necturus proximal tubule.     

Silicotungstate lowers dramatically the quantum yield of chlorophyll fluorescence in situ without affecting the rate of electron transport

Electron-transport and fluorescence properties of chloroplasts in the presence of silicotungstate are studied by O₂-evolution and fluorescence-quenching techniques. Results show that silicotungstate lowers the fluorescence quantum yield of closed units, without affecting electron-transport activities of open units. Open and closed units are units with oxidized and reduced primary electron acceptor (Q), respectively.     

Dissection of two hallmarks of the open promoter complex by mutation in an RNA polymerase core subunit

Deletion of 10 evolutionarily conserved amino acids from the beta subunit of Escherichia coli RNA polymerase leads to a mutant enzyme that is unable to efficiently hold onto DNA. Open promoter complexes formed by the mutant enzyme are in rapid equilibrium with closed complexes and, unlike the wild-type complexes, are highly sensitive to the DNA competitor heparin (Martin, E., Sagitov, V., Burova, E., Nikiforov, V., and Goldfarb, A. (1992) J. Biol. Chem. 267, 20175-20180). Here we show that despite this instability, the mutant enzyme forms partially open complexes at temperatures as low as 0 degrees C when the wild-type complex is fully closed. Thus, the two hallmarks of the open promoter complex, the stability toward a challenge with DNA competitors and the sensitivity toward low temperature, can be uncoupled by mutation and may be independent in the wild-type complex. We use the high resolution structure of Thermus aquaticus RNA polymerase core to build a functional model of promoter complex formation that accounts for the observed defects of the E. coli RNA polymerase mutants.     

Peritoneal dialysis in infants.

A commercially available closed dialysis system and a new peritoneal cannula with potential advantages for infants have been developed. The dialysis set includes three dialysate bags that may be connected to the filling burette; the warming coil of the set is placed in a thermostatically controlled water bath. The peritoneal catheter comprises a flexible tube with side holes and a sharp short bevelled needle with obturator. Advantages of the new equipment over previously available equipment are that the cannula is easier to insert; there is less risk of contaminating the dialysate since the tubing set is unbroken from supply to cannula; the mix of the dialysate may be changed easily without interrupting dialysis; and the equipment may be assembled easily by unskilled staff.     

Electrophoretic Plugging of Nuclear Pores by Using the Nuclear Hourglass Technique

The nuclear hourglass technique (NHT) was recently introduced as a novel technique that measures the electrical nuclear envelope (NE) conductance of isolated Xenopus laevis oocyte nuclei. The main conclusion drawn from NHT work so far is that nuclear pore complexes (NPCs) of oocytes are in an electrically open state under physiological conditions, with a mean conductance of 1.7 nS per NPC. Since nuclear patch-clamp data indicate that usually NPCs are electrically closed, our work has been challenged by the notion that NHT cannot assure a high resistance seal (``gigaseal') between glass wall and NE like that required for patch-clamp experiments. Thus, NHT could have dramatically underestimated NE electrical resistance. Here we demonstrate that NHT does not require a gigaseal for accurate NE conductance measurements. In addition, we present experimental conditions where mean single NPC electrical conductance is reduced 26-fold due to electrophoretic plugging by negatively charged nucleoplasmic macromolecules. In addition, data indicate that under physiological conditions (i.e., when macromolecules are offered in the cytosolic solution) the nuclear surface is heavily folded, underestimating ``true' NE surface by a factor of 2.6. When ``true' NE surface area is taken into consideration, modified values of mean single NPC conductances of 654 pS for electrically open conditions and 25 pS for electrically plugged conditions can be calculated. We conclude that the large overall NE conductance detected with the nuclear hourglass technique in intact Xenopus laevis oocyte nuclei can be explained by the sum of single NPC conductances in the pS range, as long as open probability is high. This confirms previous patch-clamp work concerning single NPC conductance, but disagrees with the view that mean open probability of NPC channels is usually low. Received: 27 March 2001/Revised: 3 July 2001