Novel Notch alleles reveal a Deltex-dependent pathway repressing neural fate

BACKGROUND

The Notch receptor triggers a wide range of cell fate choices in higher organisms. In Drosophila, segregation of neural from epidermal lineages results from competition among equivalent cells. These cells express achaete/scute genes, which confer neural potential. During lateral inhibition, a single neural precursor is selected, and neighboring cells are forced to adopt an epidermal fate. Lateral inhibition relies on proteolytic cleavage of Notch induced by the ligand Delta and translocation of the Notch intracellular domain (NICD) to the nuclei of inhibited cells. The activated NICD, interacting with Suppressor of Hairless [Su(H)], stimulates genes of the E(spl) complex, which in turn repress the proneural genes achaete/scute.

RESULTS

Here, we describe new alleles of Notch that specifically display loss of microchaetae sensory precursors. This phenotype arises from a repression of neural fate, by a Notch signaling distinct from that involved in lateral inhibition. We show that the loss of sensory organs associated with this phenotype results from a constitutive activation of a Deltex-dependent Notch-signaling event. These novel Notch alleles encode truncated receptors lacking the carboxy terminus of the NICD, which is the binding site for the repressor Dishevelled (Dsh). Dsh is known to be involved in crosstalk between Wingless and Notch pathways.

CONCLUSIONS

Our results reveal an antineural activity of Notch distinct from lateral inhibition mediated by Su(H). This activity, mediated by Deltex (Dx), represses neural fate and is antagonized by elements of the Wingless (Wg)-signaling cascade to allow alternative cell fate choices.

Maternal sensitivity as an external organizer for biobehavioral regulation in infancy

Recent findings from both animal and human research have clearly demonstrated connections between behavioral coping mechanisms and adrenocortical function. The aim of this study was to address the role of maternal sensitivity as an external organizer of psychobiological function in infants during the first year of life. Forty-one infants and their mothers were observed during play at 3, 6, and 9 months of age. Age-specific patterns of relation between maternal sensitivity and infant behavioral organization were found indicating contextual dependence of infant behavior at 3 months and experience-related behavioral function at 9 months. An affect of maternal sensitivity on adrenocortical function during the free play was demonstrated at 3 and 6 months, because an increase in cortisol was most frequently observed in infants of highly insensitive mothers. The findings indicate the importance of maternal behavior for infant biobehavioral organization.

Acute and chronic presentation of intestinal nonrotation in adults

Intestinal nonrotation has been recognized as a cause of obstruction in neonates and children and may be complicated by volvulus and intestinal necrosis. It is very rarely seen in the adult and may present acutely as a bowel obstruction and intestinal ischemia associated with midgut or ileocecal volvulus, or chronically as vague intermittent abdominal pain. The purpose of this communication is to reveal the pathogenesis and the surgical significance of intestinal nonrotation in adults and to review the English and German language literature since 1923 to establish the optimal therapeutic management. Between 1983 and 1992, we have managed and observed prospectively 10 adults with intestinal nonrotation. In four patients the nonrotation has been detected at emergency laparotomy owing to midgut or ileocecal volvulus. Four patients suffered from chronic symptoms of intermittent volvulus or small bowel obstruction and in two patients the nonrotation has been noted as an incidental finding at laparotomy for another condition. A survey of the literature from 1923 to 1992 revealed 40 adults with symptomatic intestinal nonrotation to which we contribute nine patients. We establish that in the acute symptomatic pattern, only emergency laparotomy can provide the correct diagnosis and decrease the risk of bowel disturbance. In the chronic situation, barium studies of the upper and lower gastrointestinal tract reveal varying degrees of midgut malrotation and confirm the nonrotation in each case. Also, in these forms the explorative laparotomy with a consequent staging of the abdominal situs is to be recommended. All reported cases at our institutions are without complaints after surgery. Adult patients with intestinal nonrotation and acute or chronic obstructive symptoms or those detected incidentally at laparotomy for other conditions should undergo a Ladd procedure because of the risk of midgut volvulus. In this operation, the nonrotation is left in place and the ascending colon is sutured at the colon descendens and sigmoideum. After this procedure the mesenteric pedicle is fixed and the risk of midgut torsion remains minimal.

DMSO modifies the permeability of the zebrafish (Danio rerio) chorion-implications for the fish embryo test (FET)

Since 2007, when REACH came into force, the fish embryo test has received increasing attention as a potential alternative for the acute fish test. Due to its low toxicity and the ability to permeate biological membranes without significant damage to their structural integrity, dimethyl sulfoxide (DMSO) is a commonly used solvent in the fish embryo test. Little is known, however, about the membrane penetration properties of DMSO, the impact of different concentrations of DMSO on the potential barrier function of the zebrafish chorion and on changes in the uptake of chemicals into the embryo. Therefore, in the present study, the fluorescent dyes fluorescein (mol wt 332; Pow 3.4) and 2,7-dichlorofluorescein (mol wt 401; Pow 4.7), both substances with limited water solubility, were used to visualize the uptake into the egg as well as the accumulation in the embryo of the zebrafish depending on different concentrations of DMSO. The distribution of fluorescein within the egg compartments varied with DMSO concentration: When dissolved in 0.01% DMSO, fluorescein did not pass the chorion. In contrast, concentrations ≥ 0.1% DMSO increasingly facilitated the uptake into the perivitelline space. In contrast, the uptake of 2,7-dichlorofluorescein was not substantially increased with rising DMSO concentrations, indicating the importance of factors other than the solvent (e.g. mol wt). With respect to the fish embryo test, results indicate that DMSO may be used without complications as a solvent, however, only at a maximum concentration of 0.01% (0.1 mL/L) as already indicated in the OECD difficult substances paper (OECD, 2000).

Interactions between chip and the achaete/scute-daughterless heterodimers are required for pannier-driven proneural patterning

The GATA factor Pannier activates the achaete-scute (ASC) proneural complex through enhancer binding and provides positional information for sensory bristle patterning in Drosophila. Chip was previously identified as a cofactor of the dorsal selector Apterous, and we show here that both Apterous and Chip also regulate ASC expression. Chip cooperates with Pannier in bridging the GATA factor with the HLH Ac/Sc and Daughterless proteins to allow enhancer-promoter interactions, leading to activation of the proneural genes, whereas Apterous antagonizes Pannier function. Within the Pannier domain of expression, Pannier and Apterous may compete for binding to their common Chip cofactor, and the accurate stoichiometry between these three proteins is essential for both proneural prepattern and compartmentalization of the thorax.

Metabolic control analysis of the Warburg-effect in proliferating vascular smooth muscle cells

The accumulation and proliferation of vascular smooth muscle cells (VSMC) within the vessel wall is an important pathogenic feature in the development of atherosclerosis. Glucose metabolism has been implicated to play an important role in this cellular mechanism. To further elucidate the role of glucose metabolism in atherogenesis, glycolysis and its regulation have been investigated in proliferating VSMC. Platelet derived growth factor (PDGF BB)-induced proliferation of VSMCs significantly stimulated glucose flux through glycolysis. Further evaluating the enzymatic regulation of this pathway, the analysis of flux:metabolite co-responses revealed that anaerobic glycolytic flux is controlled at different sites of gycolysis in proliferating VSMCs, being consistent with the concept of multisite modulation. These findings indicate that regulation of glycolytic flux in proliferating VSMCs differs from traditional concepts of metabolic control of the Embden-Meyerhof pathway.

Long-term results after stapled hemorrhoidopexy: high patient satisfaction despite frequent postoperative symptoms

PURPOSE

Stapled hemorrhoidopexy has been demonstrated to be advantageous in the short term compared with the traditional techniques. We aimed to evaluate long-term results after stapled hemorrhoidopexy and to assess patient satisfaction in association with postoperative hemorrhoidal symptoms.

METHODS

This prospective study included 216 patients with Grade 2 or 3 hemorrhoids, who had stapled hemorrhoidopexy using the circular stapled technique. The results were evaluated by a standardized questionnaire at least 12 months after the operation. The primary end point was patient satisfaction; secondary end points included specific hemorrhoidal symptoms.

RESULTS

Followup data were obtained for 193 of 216 patients (89 percent) with a median follow-up of 28 (range, 12-53) months, most of whom (89 percent) were satisfied or very satisfied with the surgery. The main preoperative symptom was no longer present postoperatively in 66 percent of patients, was relieved in 28 percent, and had worsened in 2 percent. Postoperative complaints included symptoms of hemorrhoidal prolapse (24 percent of patients), anal bleeding (20 percent), anal pain (25 percent) fecal soiling/leakage (31 percent), fecal urgency (40 percent), and local discomfort (38 percent). Bivariate analysis showed significant associations between each of these symptoms and patient satisfaction. Nine patients (5 percent) were reoperated on during the follow-up period.

CONCLUSIONS

Long-term patient satisfaction was high in most of patients after stapled hemorrhoidopexy for second-degree and third-degree hemorrhoids. However, an unsatisfactory outcome was significantly related to postoperative hemorrhoidal symptoms such as prolapse, fecal soiling/leakage, and new onset of fecal urgency.

Laparoscopic antireflux surgery: long-term outcomes and quality of life

BACKGROUND

To evaluate the outcome of antireflux surgery, we assessed disease-specific symptoms and quality of life of all patients treated by laparoscopic fundoplication at our center between 1992 and 2002.

MATERIALS AND METHODS

Preoperative symptoms and details of surgery were evaluated for 186 laparoscopic fundoplications. Disease-specific symptoms and quality of life were assessed using a questionnaire. Of 186 patients, 143 returned the questionnaire.

RESULTS

The most common preoperative symptoms under medical antireflux therapy were regurgitation (54%) and heartburn (30%). Indications for surgery were refractory symptoms (88%) and the patient denying long-term medication (42%). The surgical approaches were Nissen fundoplication (98%) or Toupet fundoplication (2%, for heavy esophageal motility disorder). The conversion rate was 10%. There were no deaths, and 6 patients (3%) had to be reoperated. The questionnaire revealed that in 82% of the patients who responded, the preoperative reflux symptoms were gone, and 94% were satisfied with the result and would undergo surgery again. The average gastrointestinal quality of life index was 115 points (healthy volunteers in the literature, 120.8 points).

CONCLUSION

Laparoscopic fundoplication is a safe antireflux therapy resulting in high levels of patient satisfaction and near-normal quality of life in the long term.

Early Antiretroviral Therapy in HIV-Infected Children Is Associated with Diffuse White Matter Structural Abnormality and Corpus Callosum Sparing

BACKGROUND AND PURPOSE

Fractional anisotropy in the frontal white matter, corpus callosum, and internal capsule is abnormal in human immunodeficiency virus-positive (HIV+) adults. We describe the distribution and nature of white matter abnormalities in a cohort of children who started antiretroviral therapy within the first year of life and the benefit of early treatment by using DTI measures (fractional anisotropy and mean, axial, and radial diffusion).

MATERIALS AND METHODS

DTI was performed on children in a neurodevelopmental substudy from the Children with HIV Early Antiretroviral trial. Voxel-based group comparisons were obtained to determine regions where fractional anisotropy and mean diffusion differed between HIV+ and uninfected children. Associations of DTI parameters with the timing of antiretroviral therapy initiation were examined.

RESULTS

Thirty-nine HIV+ children (15 boys; mean age, 5.4 years) and 13 controls (5 boys; mean age, 5.7 years) were scanned. Two clusters with lower fractional anisotropy and 7 clusters with increased mean diffusion were identified in the HIV+ group, with symmetric distribution predominantly due to increased radial diffusion, suggestive of decreased myelination. Corticospinal tracts rather than the corpus callosum were predominantly involved. Children on early-interrupted antiretroviral therapy had lower fractional anisotropy compared with those receiving continuous treatment.

CONCLUSIONS

HIV+ children at 5 years of age have white matter abnormalities measured by fractional anisotropy, despite early antiretroviral therapy, suggesting that early antiretroviral therapy does not fully protect the white matter from either peripartum or in utero infection. In contrast to adults, the corticospinal tracts are predominantly involved rather than the corpus callosum, possibly due to early antiretroviral therapy. Continuous early antiretroviral therapy can limit white matter damage.

Regulation of glycolytic flux in ischemic preconditioning. A study employing metabolic control analysis

Exact adjustment of the Embden-Meyerhof pathway (EMP) is an important issue in ischemic preconditioning (IP) because an attenuated ischemic lactate accumulation contributes to myocardial protection. However, precise mechanisms of glycolytic flux and its regulation in IP remain to be elucidated. In open chest pigs, IP was achieved by two cycles of 10-min coronary artery occlusion and 30-min reperfusion prior to a 45-min index ischemia and 120-min reperfusion. Myocardial contents in glycolytic intermediates were assessed by high performance liquid chromatographic analysis of serial myocardial biopsies under control conditions and IP. Detailed time courses of metabolite contents allow an in-depth description of EMP regulation during index ischemia using metabolic control analysis. IP reduced myocardial infarct size (control, 90.0 +/- 3.1 versus 5.05 +/- 2.1%; p < 0.001) and attenuated myocardial lactate accumulation (end-ischemic contents, 31.9 +/- 4.47 versus 10.3 +/- 1.26 micromol/wet weight, p < 0.0001), whereby a decrease in anaerobic glycolytic flux by at least 70% could constantly be observed throughout index ischemia. By calculation of flux:metabolite co-responses, the mechanisms of glycolytic regulation were investigated. The continuous deceleration of EMP flux in control myocadium could neither be explained on the basis of substrate availability nor be attributed to regulatory "key enzymes," as multisite regulation was employed for flux adjustment. In myocardium subjected to IP, an even pronounced deceleration of EMP flux during index ischemia was observed. Again, the adjustment of EMP flux was because of multisite modulation without any evidence for flux limitation by substrate availability or a key enzyme. However, IP changed the regulatory properties of most EMP enzymes, and some of these patterns could not be explained on the basis of substrate kinetics. Instead, other regulatory mechanisms, which have previously not yet been described for EMP enzymes, must be considered. These altered biochemical properties of the EMP enzymes have not yet been described.

Outcome and quality of life after open surgery versus endoscopic stapler-assisted esophagodiverticulostomy for Zenker's diverticulum

Two techniques for treatment of Zenker's diverticulum, endoscopic stapler-assisted esophagodiverticulostomy and open cricopharyngeal myotomy by transcervical approach, were compared with regard to patient satisfaction and quality of life. Between January 1994 and December 2004 a total of 47 patients with Zenker's diverticulum underwent surgery in our department. Besides the usual retrospective evaluation of details of surgery, all patients were sent a questionnaire on their actual complaints and quality of life according to the Gastrointestinal Quality of Life Index (GIQLI). Twenty patients had the endoscopic procedure (Group A), and 27 the open procedure (Group B). The preoperative symptoms were dysphagia in 96%, regurgitation of undigested food in 60%, cough in 19%, and pneumonia caused by recurrent aspiration in 9%. The length of surgery was on average 32 min (range 5-70 min) in Group A and 106 min (range 45-165 min) in Group B, and the length of hospital stay was 5.5 days (range 1-10 days) and 12.3 days (range 7-25 days), respectively. The results of the questionnaire showed that the preoperative symptoms had disappeared in up to 83%, and 91% in Group A and 100% in Group B would be willing to undergo surgery again. The mean GIQLI was 123 points in Group A and 118 points in Group B (healthy volunteers in the literature, 125 points). Both techniques showed good results in a long-term follow-up with regard to relief of symptoms and patient satisfaction. Both groups had an excellent Gastrointestinal Quality of Life Index, comparable to that of a healthy standard population.

Simultaneous detection of high energy phosphates and metabolites of glycolysis and the Krebs cycle by HPLC

For the detailed analysis of energy metabolism, a HPLC method is described allowing the single-run separation and quantification of most metabolites from glycolysis and the Krebs cycle including the high energy phosphates. With a detection limit in the picomolar range this method is even applicable when only small sample sizes of tissue are obtained.

Reduction in Slippage with 11-cm Lap-Band® and Change of Gastric Banding Technique

BACKGROUND

Slippage occurs after 2-18% of gastric bandings performed by the perigastric technique (PGT). We investigated the slippage-rate before and after the introduction of the pars flaccida technique (PFT) and the 11-cm Lap-Band, and the long-term results of the re-operated patients.

METHODS

Between Dec 1996 and Feb 2004, 360 patients with a mean BMI of 44 kg/m2 were operated. The PGT (n=168) and PFT9.75 (n=15) groups received the 9.75-cm Lap-Band, and the PFT11 group (n=177) received the new 11-cm Lap-Band. Follow-up rate was 99%.

RESULTS

Slippage occurred in a total of 31 patients from all groups (PGT, n=28, or 17%; PFT9.75, n=1, or 7%; PFT11, n=2, or 1%). Average yearly re-operation rate for slippage in the first 3 years postoperatively was 3.8%, 2.2% and 0.9%, respectively. Laparoscopic re-banding was necessary for posterior (n=19) or lateral (n=12) slippage. The late postoperative course after re-banding was: uneventful 58%, weight regain 35% and/or esophageal motility disorder 23%, secondary band intolerance 20%, and one persistent posterior slippage. 8 patients (26%) needed biliopancreatic diversion.

CONCLUSION

Since the introduction of the PFT and the 11-cm Lap-Band, we observed a significant reduction in slippage rate and no posterior slippage. Re-banding had a less favorable long-term result than did first-procedure banding.

First-line immune checkpoint inhibitors for extensive stage small-cell lung cancer: clinical developments and future directions

Small-cell lung cancer (SCLC) is an aggressive and rapidly growing disease with poor prognosis. Despite intense efforts to improve clinical outcomes, platinum/etoposide chemotherapy has remained the most effective regimen for first-line extensive disease SCLC for decades. The addition of immune checkpoint inhibitors, and specifically programmed death-ligand 1 inhibitors, to standard platinum/etoposide, significantly improves survival and represents a promising advance in this field. However, identification of a predictive biomarker to refine patient selection is an area of unmet need. Further understanding of tumour immunity and mechanism of resistance is required to design novel strategies that improve survival. In this review, we describe recent developments and future directions on first-line immune checkpoint blockade for extensive disease-SCLC.

Increased frequency of TIGIT+CD73-CD8+ T cells with a TOX+ TCF-1low profile in patients with newly diagnosed and relapsed AML

The inhibitory receptor TIGIT, as well as theectonucleotidases CD39 and CD73 constitute potential exhaustion markers for T cells. Detailed analysis of these markers can shed light into dysregulation of the T-cell response in acute myeloid leukemia (AML) and will help to identify potential therapeutic targets.  The phenotype and expression of transcription factors was assessed on different T-cell populations derived from peripheral blood (PB, n = 38) and bone marrow (BM, n = 43). PB and BM from patients with AML diagnosis, in remission and at relapse were compared with PB from healthy volunteers (HD) (n = 12) using multiparameter flow cytometry. An increased frequency of terminally differentiated (CD45R-CCR7-)CD8+ T cells was detected in PB and BM regardless of the disease state. Moreover, we detected an increased frequency of two distinct T-cell populations characterized by the co-expression of PD-1 or CD39 on TIGIT+CD73-CD8+ T cells in newly diagnosed and relapsed AML in comparison to HDs. In contrast to the PD-1+TIGIT+CD73-CD8+ T-cell population, the frequency of CD39+TIGIT+CD73-CD8+ T cells was normalized in remission. PD-1+- and CD39+TIGIT+CD73-CD8+ T cells exhibited additional features of exhaustion by decreased expression of CD127 and TCF-1 and increased intracellular expression of the transcription factor TOX. CD8+ T cells in AML exhibit a key signature of two subpopulations, PD-1+TOX+TIGIT+CD73-CD8+- and CD39+TOX+TIGIT+CD73-CD8+ T cells that were increased at different stages of the disease. These results provide a rationale to analyze TIGIT blockade in combination with inhibition of the purinergic signaling and depletion of TOX to improve T-cell mediated cytotoxicity in AML. Abbreviations: AML: Acute myeloid leukemia; pAML: newly diagnosed AML; rAML: relapse AML; lrAML: AML in remission; HD: healthy donor; PB: peripheral blood; BM: bone marrow; TIGIT: T-cell immunoreceptor with Ig and ITIM domains; PD-1: Programmed cell death protein 1; CD73: ecto-5'-nucleotidase; CD39: ectonucleoside triphosphate diphosphohydrolase 1; ATP: adenosine triphosphate; ADO: adenosine; CD127: interleukin-7 receptor; CAR-T cell: chimeric antigen receptor T cell; TCF-1: transcription factor T-cell factor 1; TOX: Thymocyte selection-associated high mobility group box protein; NFAT: nuclear factor of activated T cells; NA: Naïve; CM: Central Memory; EM Effector Memory; EMRA: Terminal Effector Memory cells; FMO: Fluorescence minus one; PVR: poliovirus receptor; PVRL2: poliovirus receptor-related 2; IFN-γ: Interferon-γ; IL-2: interleukin-2; MCF: multiparametric flow cytometry; TNFα: Tumornekrosefaktor α; RT: room temperature.

The learning curve of laparoscopic cholecystectomy and changes in indications: one institutions's experience with 2,650 cholecystectomies

PURPOSE

In a prospective series of 2,650 consecutive patients undergoing cholecystectomy, we analyzed the learning curve since the introduction of laparoscopic cholecystectomy (LC) in terms of operating time, conversion rate, morbidity, mortality, and consequent changes in indications for either laparoscopic or open cholecystectomy (OC).

PATIENTS AND METHODS

Between July 1990 and June 1997, LC was performed in 1,929 patients (73%), 203 of whom (7.5%) had to be converted to OC, while 518 patients (19.5%) had primary OC. Patients having LC were predominantly female, younger, with less comorbidity and less complicated gallstone disease than patients having OC.

RESULTS

Barring a learning curve during the first 6 months of LC, operating time remained constant at an average of 71 minutes while operating on ever more complex pathologies. The conversion rate decreased from 9.4% to 6.7% during the 7-year period. A relatively constant team of surgeons with growing experience as well as constantly improving technical equipment allowed the complication rate to remain low. The total morbidity of LC was 2.5% (0.1% bile duct injury), that of conversions 5%, and that of OC 12.5%. The mortality was 0 for LC, 0.5% for conversions, and 1% for OC.

CONCLUSION

The indications for primary OC decreased from 50% to 8.5% and the indications for LC could be broadened over the years.

Prevalence of postcholecystectomy symptoms: long-term outcome after open versus laparoscopic cholecystectomy

After cholecystectomy a certain number of patients continue to suffer from abdominal symptoms or develop such symptoms postoperatively. The aim of this study was to compare the prevalence of postcholecystectomy symptoms with open cholecystectomy during the prelaparoscopic era and those with laparoscopic cholecystectomy 4 years after introduction of the laparoscopic technique. Between July 1988 and June 1989 a total of 163 consecutive patients with elective open cholecystectomy and between September 1994 and August 1995 a total of 234 consecutive patients with elective laparoscopic cholecystectomy were prospectively evaluated using a standard questionnaire about preoperative symptoms, diagnostic modalities, and intraoperative findings. After a minimum of 12 months the patients were interviewed by telephone. Since the introduction of the minimal invasive technique the number of cholecystectomies performed at our institution increased. There was no significant difference in the prevalence of postcholecystectomy symptoms found after the open procedure compared with laparoscopic cholecystectomy: 90% of patients after open and 94% after laparoscopic cholecystectomy had no or only minor symptoms.

[Twelve years of laparoscopic cholecystectomy]

We studied developments in indication, operation time, conversion rate, morbidity, and mortality from the beginning of laparoscopic cholecystectomy. Between 1990 and 2002 we prospectively evaluated 4498 patients undergoing cholecystectomy (CE), of whom 79% were treated laparoscopically (lap). In 6.6%, the procedure had to be converted from laparoscopic to open cholecystectomy (con), and 14% were performed open from the beginning (open). During the above time period, the rate of open CE decreased steadily (49% in 1990 to 7.2% in 2002). The average operation time of lap CE remained constant with an average of 74 min (range 20-330). The conversion rate decreased in spite of broader indication for lap CE in even more complicated gallstone diseases, from an initial 9.4% to 2.5%. Among intraoperative complications in lap and con, bile duct lesions remained constant with 5/3856 (0.1%), bleeding which led to conversion decreased from 1.9% to 0.3%, and the rate of gall bladder perforation increased from 12% to 20.5%. Thirty-day morbidity was 2% in lap CE, 5% in con, and 11.5% in open. The mortality was 0% in lap, 0.7% in con, and 1% in open.

CONCLUSION

Since the introduction of laparoscopic cholecystectomy the indication for this minimal-invasive operation steadily increased, the conversion-rate decreased and the complication-rate could be held low. Even with fast laparoscopic experience 7% of all cholecystectomies are technically difficult and remain to be carried out primarily in an open technique. The laparoscopic cholecystectomy has become the gold standard in the therapy of gallstone disease.

Lactate accumulation rather than ATP depletion predicts ischemic myocardial necrosis: implications for the development of lethal myocardial injury

In ischemia, the myocardial metabolic status determines the expansion of necrosis. Decreased ATP levels and increased lactate contents in ischemic myocardium undergoing lethal injury are known to be related to the expansion of irreversible damage. However, their individual contributions have not yet been firmly established. Using two differently effective protocols of ischemic preconditioning (IP short and IP long), ischemic cardioplegic arrest (CP) and their combination (IP+CP) to directly influence the metabolic status of porcine myocardium, graded preservations in ATP content and decreases in lactate accumulation during 45 min ischemia could be achieved (control: ATP, 0.15+/-0.03; lactate, 60.53+/-4.89 micromol/g wet weight; IP short, 0.33+/-0.10/27.42+/-3.90; IP long, 0.60+/-0.10/17.49+/-2.14; CP, 0.98+/-0.12/11.82+/-0.96; IP+CP, 2.24+/-0.28/10.88+/-0.89; all P<0.001 vs. control). At the same time, a graded reduction of myocardial necrosis was observed (90.0+/-3.1 vs. 31.7+/-4.55 vs. 5.05+/-2.1 vs. 0.0 [isolated patchy necroses] vs. none). Regression analysis revealed only a weak correlation of infarct size and ATP preservation (r=0.567). In fact, there was a biphasic relation: with ATP levels above 1 micromol/g wet weight, no infarction occurred. ATP levels below this threshold value were associated with steep increase in infarct size. However, even for this latter range, the regression coefficient remained low (r=0.654). Instead, over the entire range, there was a close, rectilinear correlation of infarct size and lactate accumulation (r=0.939). These data indicate that lactate accumulation rather than ATP depletion determines the development of lethal myocardial injury. However, the biphasic relation between ATP depletion and infarct size suggests the latter to play a permissive role, since above a threshold value of 1 micromol/g wet weight neither substantial lactate accumulation nor infarction was observed. Below this threshold, however, infarct size increased as lactate accumulated.

[Postcholecystectomy complaints one year after laparoscopic cholecystectomy. Results of a prospective study of 253 patients]

AIMS

We studied the nature and frequency of symptoms 1 year after laparoscopic cholecystectomy in order to define pre- and perioperative factors that influence the long-term outcome.

METHOD

Between September 1994 and August 1995 we prospectively evaluated 268 patients undergoing laparoscopic cholecystectomy using a standard questionnaire. After an average of 16 months (12-25 months) the patients were asked about their symptoms using a similar questionnaire by telephone or were followed up clinically if necessary.

RESULTS

In the long-term follow-up the severity of the symptoms according to the Visick score were: Visick I (no symptoms): 164 patients (65%); Visick II: 72 (28%); Visick III: 12 (5%); Visick IV: 5 (2%). The aetiologies of the postcholecystectomy syndrome were: residual stones 1%, subhepatic liquid formation 0.8%, incisional hernia 0.4%, peptic diseases 4%, wound pain 2.4%, functional disorders 26%. Patients with typical or atypical symptoms preoperatively showed no difference in the outcome 1 year after laparoscopic cholecystectomy. Neither did the number and location of laparotomies prior to cholecystectomy or the gallbladder perforation or loss of stones intraoperatively influence the severity of the postcholecystectomy symptoms.

CONCLUSIONS

One year after laparoscopic cholecystectomy 93% of the patients have no or only minor abdominal symptoms. Neither the number and location of the laparotomies prior to cholecystectomy nor the loss of gallstones intraoperatively have an impact on the long-term result.

The stability of parenteral fat emulsions in nutrition mixtures

The effect of dilution, dextrose, amino acids and electrolytes on the stability of two parenteral fat emulsions (Travamulsion and Intralipid) were investigated. It was found that dilution of intravenous emulsions with water for injection had a different influence on the stability of the two emulsions. In addition, a dextrose concentration of 15-20% and higher, in the absence of amino acids caused coagulation of the fat droplets after storage (4 degrees C for 24 h followed by 24 h at room temperature). The addition of amino acids increased the stability of emulsions in the presence of dextrose. The differences found in the particle size distribution of the different emulsions investigated were reflected in their stability in the presence of electrolytes. Critical aggregation concentrations (monovalent cation) of 240 mmol/l for Travamulsion 10% and 156 mmol/l for Intralipid 10% were determined.

Myocardial energy metabolism in ischemic preconditioning and cardioplegia: a metabolic control analysis

For both, cardioplegia (CP) and ischemic preconditioning (IP), increased ischemic tolerance with reduction in infarct size is well documented. These cardioprotective effects are related to a limitation of high energy phosphate (HEP) depletion. As CP and IP have to be assumed to act by different mechanisms, their effects on myocardial HEP metabolism cannot be assumed to be identical. Therefore, a systematic analysis of myocardial HEP metabolism for both procedures and their combination was performed, addressing the question whether there are different effects on myocardial HEP metabolism by IP and CP. In this study, metabolic control analysis was used to analyze the regulation of HEP metabolism. In open chest pigs subjected to 45 min LAD occlusion (index ischemia), CP and IP preserved myocardial ATP (control (C) 0.14 +/- 0.05 micromol/g wwt; CP: 0.95 +/- 0.14, IP: 0.61 +/- 0.12; p<0.05 C vs. CP and IP) and reduced myocardial necrosis (infarct size IA/RA: C: 90.0 +/- 3.0%; CP: 0.0 +/- 0.0% but patchy necroses; IP: 5.05 +/- 2.1%; p<0.05 C vs. CP and IP). The effects on HEP metabolism, however, were different: CP acted predominantly by slowing down the breakdown of phosphocreatine (PCr) during early phases of ischemia (C: DeltaPCr 0-2 min: 5.24 +/- 0.32 micromol/g wwt; CP: DeltaPCr 0-2 min: 3.38 +/- 0.23 micromol/g wwt, p<0.05 vs. C), leaving ATP breakdown during later stages unaffected (C: DeltaATP 5-45 min: 1.77 +/- 0.11 micromol/g wwt CP: DeltaATP 5-45 min: 1.59 +/- 0.28 micromol/g wwt, n.s. vs. C). In contrast to CP, in IP PCr breakdown was even increased (IP: DeltaPCr 0-2 min: 7.06 +/- 0.34 micromol/g wwt, p<0.05 vs. C), but ATP depletion greatly attenuated (IP: DeltaATP 5-45 min: 0.48 +/- 0.10 micromol/g wwt, p<0.05 vs. C and CP). Combining IP and CP yielded an additive effect with slowing down the breakdown of both PCr (IP+CP: DeltaPCr 0-2 min: 5.09+/- 0.35 micromol/g wwt, p<0.05 vs. C and IP) and ATP (IP+CP: DeltaATP 5-45 min: 0.56 +/- 0.48 micromol/g wwt, p<0.05 vs. C and CP), resulting in a higher ATP content at the end of index ischemia (1.86 +/- 0.46 micromol/g wwt, p<0.05 vs. C, CP and IP). Compared to IP, combining IP+CP achieved also a further reduction in infarct size (IA/RA: 0.0 +/- 0.0%, p<0.05 vs IP) and--compared to CP--a disappearance of the patchy necroses. The concept of major differences in myocardial HEP metabolism during CP and IP is further supported at a molecular level by metabolic control analysis. CP but not IP slowed down the CK reaction velocity at high PCr levels. In contrast to CP exerting a continuous decline in vATPase for any given ATP level, in IP myocardium ATPase reaction velocity was even increased at higher ATP contents, whereas a marked decrease in ATPase reaction velocity was found if ATP levels decreased. The equilibrium of the CK-reaction remained unchanged following CP, whereas IP induced a changing CK equilibrium, which was the more shifted towards PCr the more myocardial HEP content decreased. The data demonstrate different effects of CP and IP on myocardial HEP metabolism, i.e. PCr and ATP breakdown as well as the apparent equilibrium of the creatine kinase (CK)-reaction. For these reasons the combination of the two protective interventions has an additive effect.

Renal vein thrombosis in transitional cell carcinoma

A rare case of renal transitional cell carcinoma (TCC) associated with bland thrombus of the renal vein extending into the inferior vena cava is described. Tumour thrombus in renal cell carcinoma is frequently encountered, but only very rarely occurs with TCC. Bland renal vein thrombosis occurring with renal TCC has not been described before. Contrast enhanced computed tomography assisted in distinguishing between bland and tumour thrombosis and aided in surgical management.

Comparison of paper print and soft copy reading in plain paediatric radiographs

With the introduction of a Picture Archiving and Communication System, Computed (CR) and Digital Radiography (DR), reading digital images takes place from a computer screen. Laser paper print rather than laser film would be a significantly more cost-effective option for hard copy production, but would need to demonstrate acceptable diagnostic quality compared to the reference standard of screen reading. A comparative study of 51 digital paediatric CR radiographs presented in laser paper print and soft copy format to determine the diagnostic value of the paper print when compared to the reference standard of screen reading. Chest radiography had a poor sensitivity of 66.1% while musculoskeletal and abdominal radiography had acceptable sensitivities of 90% and 99%, respectively. Specificity was excellent for the different regions (98.6-99.5%). The paper print format should not be used for diagnostic purposes in paediatric chest radiography, but may still be used for demonstration when accompanied by the radiology rapport obtained from soft copy reading. Further studies would be needed to investigate the use of paper prints in abdominal and musculoskeletal radiography owing to the low number of abdominal radiographs and lack of musculoskeletal case variety in our study.

[Incarcerated diaphragmatic hernia as a sequela of iatrogenic diaphragmatic defect. 2 case reports]

We describe two cases of iatrogenic adult diaphragmatic hernias with incarceration which occurred postoperatively and led to an acute abdomen. The pathogenesis, clinical findings, the often challenging diagnostics and the therapeutic management of this rare condition are discussed.