Mitochondrial Function in Oxidative and Glycolytic Bovine Skeletal Muscle Postmortem

ObjectivesMitochondrial function in postmortem muscle is affected by decreasing oxygenation. Functional properties relating to energy production and integrity of mitochondria may influence development of meat quality characteristics. Therefore, the objective was to evaluate changes in mitochondrial function in oxidative and glycolytic muscles during the first 24h postmortem.Materials and MethodsSteers (n = 6) of primarily Angus (80 to 100%) genetics were harvested at approximately 18.5 mo and 630 kg live weight. Samples from the longissimus lumborum (LL) and diaphragm (Dia) were collected at 1, 3, and 24h postmortem. Fresh-preserved muscle samples were permeabilized using saponin, and muscle bundles (2–4 mg) were transferred to a high-resolution oxygraph for respiration measurements (oxygen consumption rate, OCR, pmol/sec/mg of tissue). Samples were assessed in duplicate under hyperoxia. First, pyruvate and malate were added to support the TCA cycle and assess leak respiration. Then, ADP was added to support electron flow through complex I. The influence of glutamate on NADH production (complex I) was tested, followed by complex II activation by succinate. Integrity of the mitochondria outer membrane was tested with cytochrome c. Next, an uncoupler (FCCP) was added to force the electron transport system (ETS) to maximum capacity. Citrate synthase (CS) activity (nmol/min/mg tissue) was determined in frozen samples and used as a marker of mitochondria content. Subsequently, respiration data were normalized to CS activity (pmol/sec/U CS) to account for differences in mitochondria content. Coupling efficiency of oxidative phosphorylation was calculated as 1– (Leak/ADP-stimulated oxidative phosphorylation capacity). Raw and normalized OCR were analyzed in a randomized block design, with slaughter date as block and fixed effects of muscle, time, and the interaction. Time was considered a repeated measure.ResultsMuscle type affected (P = 0.0002) leak OCR, with Dia showing a higher rate than LL. After ADP was added, mitochondria from Dia exhibited higher OCR at all times tested and at all steps, with OCR being 4 times higher after FCCP addition. Mitochondrial content, evidenced by greater (P < 0.0001) CS activity in Dia, largely explained differences in OCR between muscles. After OCR was normalized to CS activity, the 1 and 3h postmortem OCR from Dia and LL were similar (P > 0.05). However, at 24h postmortem, OCR after ADP, glutamate, and FCCP additions were greater (P < 0.05) in Dia mitochondria. Time, but not muscle, affected cytochrome c response. At 1h postmortem, cytochrome c increased OCR by 6.6%, supporting that mitochondria outer membrane integrity is not compromised. However, cytochrome c response at 3h postmortem increased 52.4%, indicating outer membrane damage. Coupling efficiency is different between muscles (P = 0.005) with Dia exhibiting greater efficiency.ConclusionDespite inherent metabolic differences between the LL and Dia, mitochondria from both muscles are intact and coupled at 1h postmortem. However, by 24h postmortem, functional properties of LL mitochondria are reduced compared to Dia. Declining mitochondrial function may be associated with calcium overload, mitochondrial fragmentation, and protease activation.

Rapid Communication: Dietary selenium improves skeletal muscle mitochondrial biogenesis in young equine athletes

Exercise is known to promote mitochondrial biogenesis in skeletal muscle as well as enhance mitochondrial function and efficiency in human and rodent models. These adaptations help to decrease exercise-associated production of reactive oxygen species, which can negatively affect health and performance if antioxidant mechanisms are overwhelmed. Little is known about the adaptations of mitochondria in response to exercise training in the growing horse or if supplementation with a dietary antioxidant can improve mitochondrial function. To evaluate the separate and combined effects of selenium (Se) supplementation, training, and an acute strenuous exercise bout on mitochondrial adaptations in young horses, 30 American Quarter Horse yearlings were randomly assigned to an exercise training group or a no-training group and, within each group, received either 0.1 or 0.3 mg Se/kg DM for 14 wk. The study was split into 2 phases (wk 0 to 8 and wk 9 to 14), with half of the trained horses switched to the opposite dietary treatment in Phase 2. At the end of each phase, all horses underwent a 120-min submaximal exercise test (SET; SET 1 and SET 2). Biopsies of the middle gluteal muscle were collected before and after each phase of the study and in response to each SET and analyzed for markers of mitochondrial number and function. At rest, horses receiving 0.3 mg Se/kg DM had higher citrate synthase activity ( = 0.021) than horses receiving 0.1 mg Se/kg DM, indicating higher mitochondrial content. In contrast, cytochrome oxidase (CCO) activity was not affected by dietary Se overall, but horses that were dropped from 0.3 mg Se/kg DM to 0.1 mg Se/kg DM during Phase 2 showed a decrease ( = 0.034) in integrated CCO activity from wk 9 to 14, suggesting impaired mitochondrial function. Mitochondrial enzyme activities were unaffected by an acute, strenuous exercise bout (SET 1 and SET 2). Our relatively low-intensity exercise training protocol did not appear to induce functional mitochondrial adaptations. However, elevated dietary Se may impart beneficial effects on mitochondrial biogenesis during growth and training. A more strenuous exercise training protocol should be investigated to determine the potential benefits of elevated dietary Se for elite equine athletes.

CNTNAP2 is a direct FoxP2 target in vitro and in vivo in zebra finches: complex regulation by age and activity

Mutations of FOXP2 are associated with altered brain structure, including the striatal part of the basal ganglia, and cause a severe speech and language disorder. Songbirds serve as a tractable neurobiological model for speech and language research. Experimental downregulation of FoxP2 in zebra finch Area X, a nucleus of the striatal song control circuitry, affects synaptic transmission and spine densities. It also renders song learning and production inaccurate and imprecise, similar to the speech impairment of patients carrying FOXP2 mutations. Here we show that experimental downregulation of FoxP2 in Area X using lentiviral vectors leads to reduced expression of CNTNAP2, a FOXP2 target gene in humans. In addition, natural downregulation of FoxP2 by age or by singing also downregulated CNTNAP2 expression. Furthermore, we report that FoxP2 binds to and activates the avian CNTNAP2 promoter in vitro. Taken together these data establish CNTNAP2 as a direct FoxP2 target gene in songbirds, likely affecting synaptic function relevant for song learning and song maintenance.

5 A SINGLE NUCLEOTIDE POLYMORPHISM IN COQ9 AFFECTS MITOCHONDRIAL FUNCTION, BODY WEIGHT CHANGE AFTER CALVING, AND FERTILITY IN HOLSTEIN COWS

A single nucleotide polymorphism for COQ9 has been associated with genetic merit for fertility in 2 separate populations of Holstein cattle, with the A allele associated with higher fertility. COQ9 is necessary for the synthesis of coenzyme Q10, a component of the electron transport system of the mitochondria. We evaluated the effect of COQ9 genotype on the electron transport system, body weight changes after calving, and phenotypic measurements of fertility and production in Holstein cows. The single nucleotide polymorphism in COQ9 was genotyped using a Sequenom MassARRAY® (Sequenom Inc., San Diego, CA, USA). In the first study, cows ≥200 days in milk were selected for analysis of mitochondrial oxygen consumption [COQ9 genotype: AA (n = 12), AG (n = 12), and GG (n = 12)]. Peripheral blood mononuclear cells were isolated and respiration assessed using the Oroboros O2k high-resolution respirometer to evaluate routine respiration, R; leak respiration, L; and electron transport system capacity, E. There were additive effects of genotype on respiratory function (P < 0.05): R was 3.4 ± 0.3, 4.7 ± 0.3, and 4.9 ± 0.3 pmol of O2/s per 106 cells, L was 1.9 ± 0.3, 2.7 ± 0.3, and 3.0 ± 0.3 pmol of O2/s per 106 cells, and the uncoupling control ratio (E/R) was 3.4 ± 0.2, 2.5 ± 0.2, and 2.1 ± 0.2 for AA, AG, and GG, respectively. In a second study, body weight was recorded for AA (n = 106), AG (n = 223), and GG (n = 86) cows during the first 20 weeks postpartum for 2 consecutive lactations. In both lactations, body weight postpartum was affected by genotype × time postpartum (P < 0.001), with cows of the AA genotype experiencing less weight loss than AG (second lactation only) and GG cows. Days open, services per conception, and 305-day milk yield (MY) for the first 2 lactations were evaluated in a population of 2273 Holstein cows grouped based on predicted transmitting ability for daughter pregnancy rate: ≤–1 (n = 1220) and ≥1.5 (n = 1053). Continuous data were analysed using the MIXED procedure of SAS, and categorical data were analysed using the GLIMMIX procedure. The model included farm, genotype, and the numerator relationship matrix to account for (co)variances among animals. Additive and dominance effects were estimated. Genotype affected each trait (P < 0.05). Values for AA, AG, and GG for the first lactation were as follows: days open, 123.6 ± 3.5, 134.3 ± 2.8, and 139.4 ± 3.5 days; services per conception, 2.4 ± 0.1, 2.5 ± 0.1, and 2.7 ± 0.1; and MY, 11 278 ± 65, 11 416 ± 51, and 11 478 ± 65 kg. For the second lactation COQ9 affected (P < 0.05) days open (133.2 ± 4.7, 142.9 ± 3.1, and 147.9 ± 3.9 days) and services per conception (2.5 ± 0.1, 2.6 ± 0.8, and 2.7 ± 0.1), but there was no effect (P = 0.63) on MY (11 486 ± 66, 11 502 ± 52, and 11 526 ± 57 kg). Results indicate that the same genotype associated with genetic merit for fertility (AA) is associated with more efficient respiratory function and less body-weight loss postpartum. Moreover, the favourable genotype was associated with higher phenotypic measurements of fertility and lower MY. Results indicate the single nucleotide polymorphism in COQ9 could be a potential marker for fertility and that allelic variants may affect fertility by altering respiratory efficiency. Study was supported by USDA AFRI 2013–68004–20365.

Balancing inflammatory, lipid, and xenobiotic signaling pathways by VSL#3, a biotherapeutic agent, in the treatment of inflammatory bowel disease

BACKGROUND

The interleukin 10 knockout mouse (IL10-KO) is a model of human inflammatory bowel disease (IBD) used to study host microbial interactions and the action of potential therapeutics. Using Affymetrix data analysis, important signaling pathways and transcription factors relevant to gut inflammation and antiinflammatory probiotics were identified.

METHODS

Affymetrix microarray analysis on both wildtype (WT) and IL10-KO mice orally administered with and without the probiotic VSL#3 was performed and the results validated by real-time polymerase chain reaction (PCR), immunocytochemistry, proteomics, and histopathology. Changes in metabolically active bacteria were assessed with denaturing gradient gel electrophoresis (DGGE).

RESULTS

Inflammation in IL10-KO mice was characterized by differential regulation of inflammatory, nuclear receptor, lipid, and xenobiotic signaling pathways. Probiotic intervention resulted in downregulation of CXCL9 (fold change [FC] = -3.98, false discovery rate [FDR] = 0.019), CXCL10 (FC = -4.83, FDR = 0.0008), CCL5 (FC = -3.47, FDR = 0.017), T-cell activation (Itgal [FC = -4.72, FDR = 0.00009], Itgae [FC = -2.54 FDR = 0.0044]) and the autophagy gene IRGM (FC = -1.94, FDR = 0.01), a recently identified susceptibility gene in human IBD. Consistent with a marked reduction in integrins, probiotic treatment decreased the number of CCL5+ CD3+ double-positive T cells and upregulated galectin2, which triggers apoptosis of activated T cells. Importantly, genes associated with lipid and PPAR signaling (PPARalpha [FC = 2.36, FDR = 0.043], PPARGC1alpha [FC = 2.58, FDR = 0.016], Nr1d2 [FC = 3.11, FDR = 0.0067]) were also upregulated. Altered microbial diversity was noted in probiotic-treated mice.

CONCLUSIONS

Bioinformatics analysis revealed important immune response, phagocytic and inflammatory pathways dominated by elevation of T-helper cell 1 type (TH1) transcription factors in IL10-KO mice. Probiotic intervention resulted in a site-specific reduction of these pathways but importantly upregulated PPAR, xenobiotic, and lipid signaling genes, potential antagonists of NF-kappaB inflammatory pathways.

Variability of spike trains and the processing of temporal patterns of acoustic signals-problems, constraints, and solutions

Object recognition and classification by sensory pathways is rooted in spike trains provided by sensory neurons. Nervous systems had to evolve mechanisms to extract information about relevant object properties, and to separate these from spurious features. In this review, problems caused by spike train variability and counterstrategies are exemplified for the processing of acoustic signals in orthopteran insects. Due to size limitations of their nervous system we expect to find solutions that are stripped to the computational basics. A key feature of auditory systems is temporal resolution, which is likely limited by spike train variability. Basic strategies to reduce such variability are to integrate over time, or to average across several neurons. The first strategy is constrained by its possible interference with temporal resolution. Grasshoppers do not seem to explore temporal integration much, in spite of the repetitive structure of their songs, which invites for 'multiple looks' at the signal. The benefits of averaging across neurons depend on uncorrelated responses, a factor that may be crucial for the performance and evolution of small nervous systems. In spite of spike train variability the temporal information necessary for the recognition of conspecifics is preserved to a remarkable degree in the auditory pathway.

Distance estimation in the third dimension in desert ants

Desert ants of the genus Cataglyphis perform large-scale foraging excursions from which they return to their nest by path integration. They do so by integrating courses steered and the distances travelled into a continually updated home vector. While it is known that the angular orientation is based on skylight cues, it still is largely enigmatic how the ants measure distances travelled. We extended the ants' task into the third dimension by training them to walk within an array of uphill and downhill channels, and later testing them on flat terrain, or vice versa. In these tests the ants indicated homing distances that did not correspond to the distances actually travelled, but to the ground distances; that is, to the sum of the horizontal projections of the uphill and downhill segments of the ants' paths. These results suggest a much more sophisticated mechanism of distance estimation than hitherto thought. The ants must be able to measure the slopes of undulating terrain and to integrate this information into their "odometer" for the distance estimation process.

Solution structure of the Ras binding domain of the protein kinase Byr2 from Schizosaccharomyces pombe

BACKGROUND

After activation, small GTPases such as Ras transfer the incoming signal to effectors by specifically interacting with the binding domain of these proteins. Structural details of the binding domain of different effectors determine which pathway is predominantly activated. Byr2 from fission yeast is a functional homolog of Raf, which is the direct downstream target of Ras in mammalians that initiates a protein kinase cascade. The amino acid sequence of Byr2's Ras binding domain is only weakly related to that of Raf, and Byr2's three-dimensional structure is unknown.

RESULTS

We have solved the 3D structure of the Ras binding domain of Byr2 (Byr2RBD) from Schizosaccharomyces pombe in solution. The structure consists of three alpha helices and a mixed five-stranded beta pleated sheet arranged in the topology betabetaalphabetabetaalphabetaalpha with the first seven canonic secondary structure elements forming a ubiquitin superfold. 15N-(1)H-TROSY-HSQC spectroscopy of the complex of Byr2RBD with Ras*Mg(2+)*GppNHp reveals that the first and second beta strands and the first alpha helix of Byr2 are mainly involved in the protein-protein interaction as observed in other Ras binding domains. Although the putative interaction site of H-Ras from human and Ras1 from S. pombe are identical in sequence, binding to Byr2 leads to small but significant differences in the NMR spectra, indicating a slightly different binding mode.

CONCLUSIONS

The ubiquitin superfold appears to be the general structural motif for Ras binding domains even in cases with vanishing sequence identity. However, details of the 3D structure and the interacting interface are different, thereby determining the specifity of the recognition of Ras and Ras-related proteins.

The Ras-Byr2RBD complex: structural basis for Ras effector recognition in yeast

BACKGROUND

The small GTP binding protein Ras has important roles in cellular growth and differentiation. Mutant Ras is permanently active and contributes to cancer development. In its activated form, Ras interacts with effector proteins, frequently initiating a kinase cascade. In the lower eukaryotic Schizosaccharomyces pombe, Byr2 kinase represents a Ras target that in terms of signal-transduction hierarchy can be considered a homolog of mammalian Raf-kinase. The activation mechanism of protein kinases by Ras is not understood, and there is no detailed structural information about Ras binding domains (RBDs) in nonmammalian organisms.

RESULTS

The crystal structure of the Ras-Byr2RBD complex at 3 A resolution shows a complex architecture similar to that observed in mammalian homologous systems, with an interprotein beta sheet stabilized by predominantly polar interactions between the interacting components. The C-terminal half of the Ras switch I region contains most of the contact anchors, while on the Byr2 side, a number of residues from topologically distinct regions are involved in complex stabilization. A C-terminal helical segment, which is not present in the known mammalian homologous systems and which is part of the auto-inhibitory region, has an additional binding site outside the switch I region.

CONCLUSIONS

The structure of the Ras-Byr2 complex confirms the Ras binding module as a communication element mediating Ras-effector interactions; the Ras-Byr2 complex is also conserved in a lower eukaryotic system like yeast, which is in contrast to other small GTPase families. The extra helical segment might be involved in kinase activation.

Ant odometry in the third dimension

Desert ants (Cataglyphis) are renowned for their ability to perform large-scale foraging excursions and then return to the nest by path integration. They do so by integrating courses steered and the distances travelled into a continually updated home vector. Whereas the angular orientation is based on skylight cues, how the ants gauge the distances travelled has remained largely unclear. Furthermore, almost all studies on path integration in Cataglyphis, as well as in spiders, rodents, and humans, have aimed at understanding how the animals compute homebound courses in the horizontal plane. Here, we investigate for the first time how an animal's odometer operates when a path integration task has to be accomplished that includes a vertical component. We trained Cataglyphis ants within arrays of uphill and downhill channels, and later tested them on flat terrain, or vice versa. In all these cases, the ants indicated homing distances that corresponded not to the distances actually travelled but to the ground distances; that is, to the sum of the horizontal projections of the uphill and downhill segments of the ants' paths.

Structural consequences of mono-glucosylation of Ha-Ras by Clostridium sordellii lethal toxin

Mono-glucosylation of Ha-Ras by Clostridium sordellii lethal toxin at effector region threonine 35 has diverse effects on the Ras GTPase cycle, the dominant one of which is the inhibition of Ras-Raf coupling, leading to complete blockade of Ras downstream signaling. To understand the structural basis of the functional consequences of glucosylation, the X-ray crystal structure of glucosylated Ras-GDP was compared with that of non-modified Ras. Glucosylated Ras exhibits a different crystal packing but the overall three-dimensional structure is not altered. The glucose group does not affect the conformation of the effector loop. Due to steric constraints, the glucose moiety prevents the formation of the GTP conformation of the effector loop, which is a prerequisite for binding to the Raf-kinase. The X-ray crystal data also revealed the alpha-anomeric configuration of the bound glucose, indicating that the glucose transfer proceeds under retention of the C-1 configuration of the d-alpha-glucose. Therefore, glucosylation preserves the inactive conformation of the effector loop independently of the nucleotide occupancy, leading to a complete inhibition of downstream signaling of Ras.

Hot microscopic areas of iodine-deficient euthyroid goitres contain constitutively activating TSH receptor mutations

Constitutively activating TSH receptor mutations have been established as the most common molecular basis for the pathogenesis of toxic thyroid nodules. These mutations result in uncontrolled signalling through the TSH receptor that is likely to cause hyperfunction and proliferation. The incidence of toxic multinodular goitres has been demonstrated to be related to iodine deficiency. Moreover, scintigraphically autonomous areas are found in 40% of euthyroid goitres from iodine-deficient areas. To investigate the molecular cause of these autonomous areas, small autoradiographically hot areas were examined for somatic TSH receptor mutations using archival tissue sections from 14 patients with euthyroid goitres, which had been originally prepared nearly 20 years ago. All patients had received (125)I 17 h preoperatively for the autoradiographic investigation of their thyroid. Areas with high and low (125)I-labelling on autoradiography sections were collected separately either from serial paraffin-embedded tissue sections, or Eukitt-embedded tissue sections containing the autoradiograph. After genomic DNA extraction, the transmembrane segment of the TSH receptor was PCR-amplified and directly sequenced. Somatic TSH receptor mutations were identified in areas with high (125)I-labelling in four patients: A623I, L629P, F631L, and T632I. This is the first evidence that TSH receptor mutations occur in microscopic areas with increased (125)I-labelling in euthyroid goiters and it suggests that TSH receptor mutations in these areas confer the potential to develop into toxic thyroid nodules. It is therefore very likely that toxic thyroid nodules originate from small autonomous areas in iodine-deficient euthyroid goitres that contain a TSH receptor mutation.

Lateral optic flow does not influence distance estimation in the desert ant Cataglyphis fortis

The present account answers the question of whether desert ants (Cataglyphis fortis) gauge the distance they have travelled by using self-induced lateral optic-flow parameters, as has been described for bees. The ants were trained to run to a distant food source within a channel whose walls were covered with black-and-white gratings. From the food source, they were transferred to test channels of double or half the training width, and the distance they travelled before searching for home and their walking speeds were recorded. Since the animals experience different motion parallax cues when walking in the broader or narrower channels, the optic-flow hypothesis predicted that the ants would walk faster and further in the broader channels, but more slowly and less far in the narrower channels. In contrast to this expectation, neither the walking speeds nor the searching distances depended on the width or height of the channels or on the pattern wavelengths. Even when ventral-field visual cues were excluded by covering the eyes with light-tight paint, the ants were not influenced by lateral optic flow-field cues. Hence, walking desert ants do not depend on self-induced visual flow-field cues in gauging the distance they have travelled, as do flying honeybees, but can measure locomotor distance exclusively by idiothetic means.

Intussusception after Roux-en-Y gastric bypass

Intussusception is a common pediatric surgical problem. Its occurrence in adults is rare and usually involves a specific lead point such as a small bowel tumor or other mass. We describe two adults who developed intussusception after Roux-en-Y gastric bypass. Signs and symptoms of small bowel obstruction were seen in both of these patients, but the responsible pathology was unusual. Because of the increasing frequency with which these gastric bypass procedures are being performed, a high index of suspicion must be employed when dealing with these postoperative patients who present with abdominal complaints.

Structural and biochemical analysis of Ras-effector signaling via RalGDS

The structure of the complex of Ras with the Ras-binding domain of its effector RalGDS (RGS-RBD), the first genuine Ras-effector complex, has been solved by X-ray crystallography. As with the Rap-RafRBD complex (Nasser et al., 1995), the interaction is via an inter-protein beta-sheet between the switch I region of Ras and the second strand of the RGS-RBD sheet, but the details of the interactions in the interface are remarkably different. Mutational studies were performed to investigate the contribution of selected interface residues to the binding affinity. Gel filtration experiments show that the Ras x RGS-RBD complex is a monomer. The results are compared to a recently determined structure of a similar complex using a Ras mutant (Huang et al., 1998) and are discussed in relation to partial loss-of-function mutations and the specificity of Ras versus Rap binding.

Structure of the Ras-binding domain of RalGEF and implications for Ras binding and signalling

The solution structure of the Ras-binding domain (RBD) of Ral guanine-nucleotide exchange factor RalGEF was solved by NMR spectroscopy. The overall structure is similar to that of Raf-RBD, another effector of Ras, although the sequence identity is only 13%. 15N chemical shifts changes in the complex of RalGEF-RBD with Ras indicate an interaction similar to the intermolecular beta-sheet observed for the complex between Ras and Raf-RBD.

Isolation of a novel type-I fatty-acid synthetase from Euglena gracilis. Specific derepression in streptomycin-bleached cells

A novel, high-molecular-mass fatty-acid synthetase (FAS) complex has been isolated from streptomycin-bleached Euglena gracilis cells. The enzyme was purified 250-fold from the crude cell homogenate and subsequently migrated upon SDS/PAGE as a single band of molecular mass 270 kDa. This apparent subunit size of the purified protein contrasted with a smaller size of only 200 kDa which was exhibited by the same protein upon immunoblotting of the crude cell extract. The purified Euglena FAS complex cosediments in a sucrose density gradient with yeast FAS and, from this, both enzymes were concluded to have the same overall molecular mass of 2.3 MDa. The enzyme described in this paper appears to be a typical type-I FAS multienzyme which clearly differs from the E. gracilis FAS so far described. Instead, it appears to be organized structurally similar to the type-I FAS multienzymes of lower fungi. In vitro, the purified Euglena FAS complex synthesizes mainly palmitic acid, or its CoA ester, from acetyl CoA and malonyl CoA as substrates. The Km values for acetyl CoA and malonyl CoA are 20 microM and 31 microM, respectively. Similar to the FAS enzymes of other lower eucaryotes, the Euglena type-I FAS is a flavoprotein. In contrast to yeast FAS, however, the flavin cofactor appears to be covalently attached to the enzyme protein. By immunological techniques, the enzyme was shown to be absent in green as well as in etiolated E. gracilis cells, while being rapidly induced upon streptomycin bleaching of heterotrophically growing green cells. The data suggest an inverse correlation between organellar development and derepression of this FAS complex.

Scar endometriosis

Scar endometriosis is a rare entity most commonly seen after surgical treatment of the uterus or fallopian tubes. We report three additional instances of scar endometriosis after cesarean sections as well as a patient who had synchronous scar endometriomas at separate surgical sites.

Early experience utilizing the in situ saphenous vein technique in 54 patients

We have compared our early and late experience utilizing in situ saphenous vein bypass graft for lower extremity arterial occlusive disease in 54 patients who underwent in situ femoral to popliteal and distal bypass grafts between July of 1983 and February 1985. There were 3 femoral to above-knee popliteal bypasses, 27 femoral to below-knee popliteal bypass grafts, 12 femoral to anterior tibial dorsalis pedis bypass grafts, 10 femoral to posterior tibial bypass grafts and 2 femoral to peroneal in situ bypass grafts. The operative indications were progressive disabling claudication in 8 (15%) and limb salvage in 46 (85%). Eighty-nine percent of the limb salvage patients had 0-1 vessel runoff by arteriogram. Cumulative life table patency of the 54 in situ bypass grafts was 79% at 20 months. One hundred percent of the patients who were operated on for disabling claudication had patent grafts at 20 months. Seventy-eight percent of the limb salvage patients had patent grafts. Fourteen of the limb salvage patients required amputation and of these 14, 10 had patent grafts at the time of amputation. There were 8 deaths in the series. Our results demonstrate that a definite learning curve exists with this technique, however, once established, long-term patency and improved limb salvage statistics can be obtained.