Safety and Efficacy of Metabolic Surgery in Patients with Type 2 Diabetes in the Middle East and North Africa Region: An Analysis of Primary Roux-en-Y Gastric Bypass and Sleeve Gastrectomy Outcomes

INTRODUCTION

Type 2 diabetes (T2D) is a chronic medical condition that results in significant health implications and reduced life expectancy. The International Diabetes Federation (IDF) estimated that in 2021, 51.8% of all deaths of people under 60 years old in the Middle East and North Africa (MENA) region were related to diabetes. Bariatric surgery has been demonstrated to be a safe and effective treatment for T2D in different populations worldwide, though few specific data exist on outcomes of procedures in the MENA region. The aim of this study was to compare the safety and postoperative outcomes between patients with and without T2D undergoing primary bariatric surgery at a tertiary referral academic medical center in the United Arab Emirates.

METHODS

All patients who underwent primary metabolic surgery between September 2015 and July 2020 were retrospectively reviewed from a prospective database. Group 1 included patients with T2D, and Group 2 included patients without T2D. Patients undergoing revisional or correctional operations were excluded. The procedure performed was based on surgeon discretion in discussion with a multidisciplinary team and the patient. Demographics as well as perioperative and postoperative results were examined.

RESULTS

Our study included 542 patients, 160 (29.5%) with T2D and 382 (70.5%) with non-T2D. Mean age was 44.5 years (range 16-70) in the T2D group and 33.3 years (range 15-63) in the non-T2D group; median BMI was 41.8 ± 7.3 and 43.2 ± 7.2, respectively. The T2D group was 37.5% male and 62.5% female, and the non-T2D group was 38.7% male and 61.3% female. There were no significant differences in comorbidities. In the T2D group, 45.6% of patients underwent Roux-en-Y gastric bypass and 54.4% sleeve gastrectomy. In the non-TD2 group, 42.7% of patients received Roux-en-Y gastric bypass and 57.3% sleeve gastrectomy. There were no statistically significant differences in postoperative ED visits (21.8% vs. 24.3%, p = 0.21), minor complications within 30 days (4.3% vs. 5.2%, p = 0.67), readmission rates (5.6% vs. 4.9%, p = 0.77), re-operation rates (3.7% vs. 1.5%, p = 0.11), median hospital stay (2.0 days vs. 3.0, p = 0.05), or complications after 30 days (6.2% vs. 11.2%, p = 0.07). There were no deaths either group.

CONCLUSIONS

In this cohort of patients from the MENA region, bariatric surgery in T2D patients is safe and effective, with perioperative outcomes comparable to those of non-T2D patients. To the best of our knowledge, our postoperative findings, which are the first report in the MENA region, are consistent with studies published in North America and Europe.

Conversion of Sleeve Gastrectomy to Roux-en-Y Gastric Bypass to Enhance Weight Loss: Single Enterprise Mid-Term Outcomes and Literature Review

Background

Suboptimal weight loss (SWL) occurs up to 30% after sleeve gastrectomy (SG). Conversion to Roux-en-Y gastric bypass (cRYGB) has shown heterogeneous results in terms of additional weight loss and resolution of weight-related comorbidities. We aim to evaluate mid-term outcomes of cRYGB specifically for SWL after SG.

Methods

All patients who underwent cRYGB for SWL from April 2010 to June 2019 from prospective registries at three affiliated tertiary care centers were retrospectively reviewed. Patients who underwent revision or conversion for complications were excluded. Mixed-effects and polynomial regression models were used to evaluate weight loss results after conversion.

Results

Thirty-two patients underwent cRYGB from SG. About 68.7% were women with mean age of 46.6 years. Mean body mass index (BMI) before SG was 55.3 kg/m². Before conversion, mean BMI was 44.5 kg/m² with 17.3% total weight loss (TWL). All procedures were completed laparoscopically in a median surgical time of 183 min. Three major complications occurred (9.3%), one gastrojejunal (GJ) leak and two reoperations. Four cases (12.5%) of GJ stenosis were diagnosed. No mortality was registered. Mean follow-up time was 24 months and patients had 36 kg/m² mean BMI, 17.4% TWL, 27.2% had BMI >35 kg/m².

Conclusions

cRYGB after SG for SWL showed good mid-term results, better than those reported in literature.

Gastroparesis with concomitant gastrointestinal dysmotility is not a contraindication for per-oral pyloromyotomy (POP)

INTRODUCTION

Per-oral pyloromyotomy (POP or G-POEM) provides significant short-term improvements in symptoms and objective emptying for patients with medically refractory gastroparesis, but it is unclear if patients with gastroparesis and co-existing dysmotility (small bowel or colonic delay) also benefit. In this study, we used wireless motility capsule (WMC) data to measure outcomes in patients with isolated gastroparesis (GP) and gastroparesis with co-existing dysmotility (GP + Dys) who underwent POP.

METHODS

We retrospectively analyzed patients who had POP and completed WMC data during their evaluation of intestinal dysmotility. WMC data were reviewed to identify patients who demonstrated isolated GP or GP + Dys. Each patient's pre-op and post-op Gastroparesis Cardinal Symptom Index (GCSI) and 4-h solid-phase scintigraphy gastric emptying studies (GES) scores were compared to evaluate improvement.

RESULTS

Of the entire cohort (n = 73), 89% were female with a mean age of 47.0 ± 15.0 years old. Gastroparesis etiologies were divided among idiopathic (54.8%), diabetic (26%), postsurgical (8.2%), autoimmune (5.5%), and multifactorial (5.5%). Forty-one patients (56%) had GP and 32 patients (44%) had GP + Dys. GCSI improved after POP whether the patient had isolated GP (- 12.31, p < 0.001) or GP + Dys (- 9.58, p < 0.001); however, there was no significant difference in total GCSI improvement between the two groups. A subset of patients had postoperative GES available (n = 47). In the isolated GP and GP + Dys cohorts, 15/28 (54%) and 12/19 (63%) patients had normal post-op 4-h GES, respectively, but no statistical difference between the two groups.

CONCLUSION

Patients with medically refractory gastroparesis with and without concomitant gastrointestinal dysmotility show short-term subjective and objective improvement after POP. Concomitant small bowel or colonic dysmotility should not deter physicians from offering POP in carefully selected patients with gastroparesis.

Scanning the solutions for the sustainable supply of forest ecosystem services in Europe

Forests are key components of European multifunctional landscapes and supply numerous forest ecosystem services (FES) fundamental to human well-being. The sustainable provision of FES has the potential to provide responses to major societal challenges, such as climate change, biodiversity loss, or rural development. To identify suitable strategies for the future sustenance of FES, we performed a solution scanning exercise with a group of transdisciplinary forest and FES experts from different European regions. We identified and prioritized fifteen major challenges hindering the balanced provision of multiple FES and identified a series of potential solutions to tackle each of them. The most prominent challenges referred to the increased frequency and impacts of extreme weather events and the normative mindset regarding forest management. The respective solutions pointed to the promotion of forest resilience via climate-smart forestry and mainstreaming FES-oriented management through a threefold strategy focusing on education, awareness raising, and networking. In a subsequent survey, most solutions were assessed as highly effective, transferable, monitorable, and with potential for being economically efficient. The implementation of the solutions could have synergistic effects when applying the notion of leverage points. Seven emerging pathways towards the sustainable supply of FES have been identified. These pathways build on each other and are organized based on their potential for transformation: (1) shifting forest management paradigms towards pluralistic ecosystem valuation; (2) using integrated landscape approaches; (3) increasing forest resilience; (4) coordinating actions between forest-related actors; (5) increasing participation in forest planning and management; (6) continuous, open, and transparent knowledge integration; and (7) using incentive-based instruments to support regulating and cultural FES. These pathways can contribute to the implementation of the new EU Forestry Strategy to support the balanced supply of multiple FES.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s11625-022-01111-4.

Natural history of lung function over one year in patients with Parkinson's disease

BACKGROUND

Little is known about decline in lung function in Parkinson's disease (PD). To assess these changes, we assessed the changes in lung function that occurred over 12 months in patients on standard PD therapy as part of the observational cohort of an open-label study of inhaled levodopa (CVT-301) in PD.

METHODS

PD patients on stable oral PD therapy and no chronic respiratory disease had spirometry and diffusing capacity of the lungs for carbon monoxide (DL_CO) measured at 3, 6, 9, and 12 months.

RESULTS

106 patients (81.5%) in the observational cohort on no investigational therapy completed the study. Mean FEV₁ declined at 12 months from 2.88L at baseline with a mean change of -0.11L, greater than the -0.030-0.045L/year observed in healthy, non-smokers aged 60-70 years. FVC declined from 3.77L (mean change -0.19L); FEV₁/FVC ratio remained relatively constant. DL_CO mean change was -0.48 mL/min/mmHg from a baseline of 24.24 mL/min/mmHg. This change in DL_CO, while not significant, was similar to that seen in non-smokers aged 60-70 years (DL_CO -0.42-0.63 mL/min/mmHg/year). Decreases in alveolar volume (VA) and inspiratory vital capacity (IVC) rather than the transfer coefficient (DL_CO/VA) were observed.

CONCLUSIONS

PD patients had greater declines in FEV₁, and FVC, but not in DL_CO, compared to healthy non-smokers of similar age. Declines in FEV₁ and FVC with little change in FEV₁/FVC, and decline in VA and IVC with little change in DL_CO/VA, suggest these changes were due to decreases in lung volume and are compatible with progressive PD-associated respiratory muscle weakness.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT02352363 Registered January 26, 2015 [https://clinicaltrials.gov/ct2/show/NCT02352363]) and EudraCT (2014-003799-22).

Efficacy of Virtual Case-Based General Surgery Clerkship Curriculum During COVID-19 Distancing

OBJECTIVE

The COVID-19 pandemic created a paradigm shift in medical education with a reliance upon alternative teaching methods to deliver meaningful surgery clerkship content. This study examines the efficacy of a novel, case-based virtual surgery clerkship curriculum to determine its impact on student experience during quarantine.

STUDY DESIGN

Sixteen third-year medical students enrolled in the General Surgery clerkship between April through June 2020 during COVID-19 distancing at a quaternary medical center (Cleveland Clinic, Cleveland, OH) participated in this study. Course surveys, including a 10-question curriculum-based multiple-choice assessment, were administered before and after the clerkship. Analyses include student self-perception of readiness to see a surgical consult independently, students' interest in pursuing a General Surgery residency, and improvement of surgical knowledge.

RESULTS AND CONCLUSION

On a 5-point Likert scale, students felt significantly more assured in their ability to independently assess a surgical consult by the end of the course. Five (31%) students reported an influence of the curriculum on their personal interest in a career in General Surgery. Mean scores on the curriculum-based knowledge assessment increased. These findings highlight that a virtual platform can be a reliable alternative adjunct that delivers surgical content and positively impacts student experience.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s40670-020-01126-5.

Real-time intraoperative functioning lumen imaging probe during endoscopic per-oral pyloromyotomy (pop)

Background

Endoscopic per-oral pyloromyotomy (POP) has emerged as a safe and effective first line option in medically refractory gastroparesis. Determining the appropriate extent of the pyloromyotomy continues to present a challenge as there are no standardized tools for measuring changes in pyloric distensibility during the procedure. The objective of this study was to evaluate the utility of using impedance planimetry with endoscopic functional luminal imaging probe (FLIP) to measure changes in pyloric distensibility after POP, and to compare these changes with improvement in symptoms and objective gastric emptying.

Methods

Patients with medically refractory gastroparesis underwent POP with FLIP measurements of the pylorus (EndoFLIP®, Medtronic, Fridley MN). FLIP measurements, as well as changes in symptoms measured by the validated gastroparesis cardinal symptom index (GCSI) and scintigraphic gastric emptying studies (GES), were evaluated before and after POP.

Results

A total of 14 patients underwent measurement with FLIP during POP, 12 of whom had pre- and post-POP measurements. Mean pyloric diameter increased by 1.4 mm, from 13.9 mm to 15.3 mm (p = 0.0012). Mean distensibility index increased from 6.2 mm²/mmHg to 9.1 mm²/mmHg (p = 0.0074). Successful division of the pylorus was achieved in 100% of patients with a mean operative time of 36 min and no perioperative complications. The mean length of stay was 0.7 days (0–3 days). Post-POP mean GCSI score improved from 2.97 to 2.28 at a mean follow-up time of 27 days (p < 0.001). Objective improvement in gastric emptying was observed in 80% of patients with scintigraphic GES, with mean four-hour retention decreasing from 46.3% to 32.4% (p < 0.007).

Conclusions

FLIP is a safe and feasible tool to provide objective measurements during POP. Larger cohorts with longer follow-up are required to determine if measured improvements in pyloric diameter and distensibility are predictive of sustained improvements in GCSI and GES.

Die zerebralen Venen- und Sinusthrombosen in der Geburtshilfe

An 37 Fällen der Literatur und 13 eigenen Beobachtungen werden die Symptome der zerebralen Venen- und Sinusthrombose beschrieben. Das erste ist meistens ein epileptischer Anfall, weniger häufig ist ein Beginn mit Kopfschmerzen oder Lähmungen. Die Krampfanfälle treten in den ersten 24 Stunden in den Vordergrund. Später dominieren die Lähmungen. Der Augenfundus und der Liquor können negativ sein. Pathologisch-anatomisch findet sich meistens eine Thrombose des Sinus sagittalis superior, nie eine solche des Sinus cavernosus. Die Ätiologie dürfte in einer autochthonen Thrombose liegen, weist doch das Wochenbett bekanntlich eine hohe Thrombosemorbidität auf. Altersverteilung, Parität und gehäuftes Auftreten nach schweren Geburten sprechen ebenfalls dafür. Die Differentialdiagnose ist oft schwierig.

Die Therapie muß meistens antithrombotisch, antiepileptisch und hirndruck-erniedrigend wirken. Prognostisch ist die Krankheit viel günstiger als der schwere akute Zustand vermuten läßt.

Dalfampridine Effects Beyond Walking Speed in Multiple Sclerosis

BACKGROUND

Dalfampridine extended release (ER) improves walking in people with multiple sclerosis (MS), as demonstrated by walking speed improvement. This exploratory study evaluated treatment effects of dalfampridine-ER on gait, balance, and walking through treatment withdrawal and reinitiation.

METHODS

Dalfampridine-ER responders, based on Timed 25-Foot Walk (T25FW) assessment before study entry, were included in this open-label, three-period, single-center study. Period 1: on-drug evaluations performed at screening and 1 week after screening. Period 2: dalfampridine-ER withdrawal and off-drug evaluations (days 5 and 11). Period 3: dalfampridine-ER reinitiation/final on-drug evaluation (day 15).

PRIMARY OUTCOME VARIABLES

NeuroCom composite scores for gait and balance; balance was evaluated if gait changes were significant. Secondary variables: individual NeuroCom scores, walking speed (T25FW) and distance (2-Minute Walk Test [2MWT]), and balance (Berg Balance Scale [BBS]).

RESULTS

All 20 patients completed the study: mean age, 53.1 years; mean MS duration, 11.3 years; mean time taking dalfampridine-ER, 315.3 days. NeuroCom gait composite scores worsened during period 2 relative to period 1 and improved during period 3; the mean ± SD difference in gait composite scores on drug was 4.03 ± 1.51 points (P = .015). Balance composite scores did not change significantly. Improvements were observed for off-drug versus on-drug for T25FW (0.36 ft/sec, P < .001), 2MWT (25.4 ft, P = .006), and BBS (1.7 points, P = .003). Safety profile was consistent with previous studies.

CONCLUSIONS

Significant improvements in gait, walking speed, distance, and balance were demonstrated by dalfampridine-ER reinitiation after a 10-day withdrawal period.

Evaluation of Dalfampridine Extended Release 5 and 10 mg in Multiple Sclerosis: A Randomized Controlled Trial

BACKGROUND

Dalfampridine extended-release (ER) tablets, 10 mg twice daily, have been shown to improve walking in people with multiple sclerosis. We evaluated the safety and efficacy of dalfampridine-ER 5 mg compared with 10 mg.

METHODS

Patients were randomized to double-blind treatment with twice-daily dalfampridine-ER tablets, 5 mg (n = 144) or 10 mg (n = 143), or placebo (n = 143) for 4 weeks. Primary efficacy endpoint was change from baseline walking speed by the Timed 25-Foot Walk 3 to 4 hours after the last dose. At 40% of sites, 2-week change from baseline walking distance was measured by the 6-Minute Walk test.

RESULTS

At 4 weeks, walking speed changes from baseline were 0.363, 0.423, and 0.478 ft/s (placebo, dalfampridine-ER 5 mg, and dalfampridine-ER 10 mg, respectively [P = NS]). Post hoc analysis of average changes between pretreatment and on-treatment showed that relative to placebo, only dalfampridine-ER 10 mg demonstrated a significant increase in walking speed (mean ± SE): 0.443 ± 0.042 ft/s versus 0.303 ± 0.038 ft/s (P = .014). Improvement in 6-Minute Walk distance was significantly greater with dalfampridine-ER 10 mg (128.6 ft, P = .014) but not with 5 mg (76.8 ft, P = .308) relative to placebo (41.7 ft). Adverse events were consistent with previous studies. No seizures were reported.

CONCLUSIONS

Dalfampridine-ER 5 and 10 mg twice daily did not demonstrate efficacy on the planned endpoint. Post hoc analyses demonstrated significant increases in walking speed relative to placebo with dalfampridine-ER 10 mg. No new safety signals were observed.

Metastasizing Esthesioneuroblastoma in a Dog

A 7-year-old Afghan hound presented with a history of disorientation, loss of vision, and seizures. Magnetic resonance imaging helped identify a mass at the level of the main olfactory bulb that compressed and displaced adjacent tissues in the cribriform plate into the nasal cavity and nasopharynx. Bony structures were osteolytic. After removing almost 80% of the mass, the tumor recurred a few months later. Due to severe respiratory distress and subsequent to an ultrasound diagnosis of a liver tumor, the dog was euthanized. In addition to the nasal mass, a single nodule in the liver and multiple nodules in the lung were present. All masses had similar cell morphology and were diagnosed as metastasizing esthesioneuroblastoma. The neoplastic cells expressed neuron-specific enolase and chromogranin A, and a few cells within the nasal mass were positive for cytokeratin. This is the first description of a canine esthesioneuroblastoma with distant metastases.

A pooled analysis of two phase 3 clinical trials of dalfampridine in patients with multiple sclerosis

BACKGROUND

Two phase 3 clinical trials demonstrated that dalfampridine extended-release 10-mg tablets (D-ER), twice daily, significantly improved walking relative to placebo in patients with multiple sclerosis (MS). The objective of this study was to evaluate the efficacy and safety of D-ER in patients with MS using pooled data from the two phase 3 trials.

METHODS

Data were pooled from the two trials, and D-ER was compared with placebo for timed-walk responder rate, changes in walking speed, and the 12-item Multiple Sclerosis Walking Scale (MSWS-12). Response rates were evaluated with respect to demographic and clinical characteristics.

RESULTS

D-ER had a significantly higher proportion of timed-walk responders relative to placebo (37.6% vs. 8.9%; P < .0001). The responder rate was independent of age, gender, race, body-mass index, type of MS, duration of MS, baseline Expanded Disability Status Scale score, baseline walking speed, and concomitant use of immunomodulatory therapies. Significant improvements were observed in walking speed and in MSWS-12 score for the pooled D-ER group compared with placebo. The safety profile was consistent with the individual studies; no new safety or tolerability concerns were identified.

CONCLUSIONS

D-ER demonstrated efficacy for the improvement of walking in patients with MS; response was independent of demographic and clinical characteristics.

Genetic variations in polyunsaturated fatty acid metabolism--implications for child health?

Sufficient nutritional supply with polyunsaturated fatty acids (PUFAs) has long been considered as beneficial for child health, especially in regard to neuronal development and allergic diseases. In recent years, genetic association studies showed that in addition to nutritional influences, the genetic background is highly important for PUFA composition in human tissues. Specifically, polymorphisms in the fatty acid desaturase genes or FADS determine the efficiency of how PUFAs are processed endogenously. Recent gene-nutrition interaction studies suggest that these polymorphisms modulate the effect of nutritional fatty acid intake on complex phenotypes such as cognitive outcomes and asthma risk in children. These early results may provide the basis for future well-specified dietary recommendations to achieve optimal health benefit for all children. This article presents results from recent gene-nutrition interaction studies, discusses its implications for child health, and gives an outlook how this association might translate into clinical practice in the future.

piggyBac-mediated germline transformation in the beetle Tribolium castaneum

The lepidopteran transposable element piggyBac can mediate germline insertions in at least four insect orders. It therefore shows promise as a broad-spectrum transformation vector, but applications such as enhancer trapping and transposon-tag mutagenesis are still lacking. We created, cloned, sequenced and genetically mapped a set of piggyBac insertions in the red flour beetle, Tribolium castaneum. Transpositions were precise, and specifically targeted the canonical TTAA recognition sequence. We detected several novel reporter-expression domains, indicating that piggyBac could be used to identify enhancer regions. We also demonstrated that a primary insertion of a non-autonomous element can be efficiently remobilized to non-homologous chromosomes by injection of an immobile helper element into embryos harbouring the primary insertion. These developments suggest potential for more sophisticated methods of piggyBac-mediated genome manipulation.

Analysis of FA contents in individual lipid fractions from human placental tissue

Data on FA contents in the human placenta are limited. Different methods have been used for the FA analysis, and only percentage results have been presented. We developed and evaluated a method for the determination of FA concentrations in placental tissue. Lipids were extracted from placental tissue with a chloroform/methanol mixture; and phospholipids (PL), nonesterified FA (NEFA), TG, and cholesterol esters (CE) were isolated by TLC. Individual lipid fractions were derivatized with methanolic hydrochloric acid, and the FAME were quantified by GC with FID. The CV of intra-assay (n = 8) of absolute concentrations were evaluated for FA showing a tissue content > 0.01 mg/g. CV ranges were 4.6-11.0% for PL, 6.4-9.3% for NEFA, 6.1-8.9% for TG, and 11.4-16.3% for CE. The relative FA composition across a term placenta indicated no differences between samples of central and peripheral locations of maternal and fetal site (CV 0.5-9.9%), whereas the absolute FA concentrations were only reproducible in the PL fraction (CV 7.0-12.8%). The method shows a reasonably high precision that is well suited for physiological and nutritional studies.

Expression of dachshund in wild-type and Distal-less mutant Tribolium corroborates serial homologies in insect appendages

We isolated the homologue of the Drosophila gene dachshund (dac) from the beetle Tribolium castaneum. Tc'dac is expressed in all appendages except urogomphi and pleuropodia. Tc'dac is also active in the head lobes, in the ventral nervous system, in the primordia of the Malpighian tubules and in bilateral stripes corresponding to the presumptive dorsal midline. Expression of Tc'dac in the labrum lends support to the interpretation that the insect labrum is derived from a metameric appendage. The legs of Tribolium accommodate two Tc'dac domains, of which the more distal one corresponds to the single dac domain described for Drosophila leg discs. In contrast to Drosophila, where this domain is thought to intercalate between the homothorax (hth) and the Distal-less (Dll) domains, in Tribolium it arises from within the Dll domain. In embryos mutant for the Tc'Dll gene we find that the distal Tc'dac domain in the legs, as well as the expression in the labrum, are deleted while the proximal leg domain and the mandibular expression are unaffected. Based on Tc'dac expression in wild-type and mutant embryos, we demonstrate serial homology of the complete mandible with the coxa of the thoracic legs, which affirms the gnathobasic nature of the insect mandible.

The influence of airway pressure changes on intracranial pressure (ICP) and the blood flow velocity in the middle cerebral artery (VMCA)

OBJECTIVE

Due to the exponential shape of the intracranial volume-pressure relation, simple measurement of epidural, parenchymal or intraventricular intracranial pressure (ICP) in traumatic brain injury (TBI) often fails to early recognize patients with a fulminant development of intracranial hypertension even during recently available methods of tissue PO2 and microdialysis measurements. One approach to this problem could be repetitive intracranial volume provocations to evaluate a trend of the intracranial elastance. Several previously published methods use invasive volume challenge through access to the cerebrospinal fluid (CSF). This pilot study describes changes in intracranial pressure due to variations of airway pressure with BIPAP ventilation maneuvers.

PATIENTS AND METHODS

Ten patients with severe TBI were enrolled and completed the study. The inclusion was based on radiologic signs due to TBI in the first CT-scan and the clinical indication for insertion of an ICP monitoring device. Patients with elevated ICP above 20 mm Hg were excluded. The epidural ICP response together with haemodynamic parameters in relation to defined airway pressure changes (delta PAW) was detected. The influence of the duration of delta PAW was evaluated additionally. Data of central venous pressure (CVP), ICP, mean arterial pressure (MAP), cerebral perfusion pressure (CPP), airway pressure (PAW) and blood flow velocity of the middle cerebral artery (VMCA) were analyzed on the basis of differences between the maximum (inspiration) and minimum PAW values (expiration).

RESULTS

Elevations of PAW in the range of 20 to 35 cm H2O resulted in changes of the ICPmean from 4.1 to 6.0 mm Hg (r = 0.9, p < 0.05). A correlation was estimated for the changes of systolic arterial pressure (Part) and CPPmean due to PAW variations which ranged between 4.5 and 11.6 mm Hg (r = 0.99, p < 0.05). Concerning the transcranial doppler measurements the data of changes of the blood flow velocity of the middle cerebral artery (VMCA) revealed a positive correlation to PAW with a r = 0.99, p < 0.05.

CONCLUSIONS

Elevation of the venous outflow resistance and a transient increase in cardiac output have to be considered as mechanisms for transduction of transthoracic pressure changes to intracranial pressure variations. We conclude, that trends of changes in elastance can be derived from intermittent airway pressure variations. This can be useful in easy and on line dynamic monitoring of ICP in traumatic brain injury.

Quantitative analysis of gene function in the Drosophila embryo

The specific functions of gene products frequently depend on the developmental context in which they are expressed. Thus, studies on gene function will benefit from systems that allow for manipulation of gene expression within model systems where the developmental context is well defined. Here we describe a system that allows for genetically controlled overexpression of any gene of interest under normal physiological conditions in the early Drosophila embryo. This regulated expression is achieved through the use of Drosophila lines that express a maternal mRNA for the yeast transcription factor GAL4. Embryos derived from females that express GAL4 maternally activate GAL4-dependent UAS transgenes at uniform levels throughout the embryo during the blastoderm stage of embryogenesis. The expression levels can be quantitatively manipulated through the use of lines that have different levels of maternal GAL4 activity. Specific phenotypes are produced by expression of a number of different developmental regulators with this system, including genes that normally do not function during Drosophila embryogenesis. Analysis of the response to overexpression of runt provides evidence that this pair-rule segmentation gene has a direct role in repressing transcription of the segment-polarity gene engrailed. The maternal GAL4 system will have applications both for the measurement of gene activity in reverse genetic experiments as well as for the identification of genetic factors that have quantitative effects on gene function in vivo.

Clostridium botulinum C2 toxin delays entry into mitosis and activation of p34cdc2 kinase and cdc25-C phosphatase in HeLa cells

The Clostridium botulinum C2 toxin ADP-ribosylates monomeric actin, thereby inducing disassembly of actin filaments, alteration of focal adhesions, and rounding of cells. After treatment with C2 toxin, cells stop to proliferate but remain viable for about 2 days. In view of reported correlations between the structure of the actin cytoskeleton and cell cycle transition, the effects of C2 toxin on the G(2)/M phase transition of the cell division cycle were studied. Since C2 toxin delayed entry into mitosis in HeLa cells, those enzymes which control entry into mitosis, the cyclin-dependent protein kinase mitosis-promoting factor (MPF) and the phosphatase cdc25-C were examined after treatment of synchronized cells with C2 toxin. MPF is composed of the regulatory cyclin B and the enzymatic p34cdc2 kinase subunits. For its activation at the G2/M border, p34cdc2 needs to be associated with cyclin B and additionally dephosphorylated at Tyr-15 by the specific phosphatase cdc25-C. Treatment of synchronized cells in S or G2 phase with C. botulinum C2 toxin prevented p34cdc2 protein kinase activation by inhibiting its tyrosine dephosphorylation at the G2/M border. Furthermore, the activity of cdc25-C phosphatase was decreased after treatment of cells with C2 toxin. Our results suggest that the prevented activation of the mitotic inducers p34cdc2 kinase and cdc25-C phosphatase represents the final downstream events in the action of C2 toxin resulting in a G(2) phase cell cycle delay in synchronized HeLa cells.

A system to efficiently maintain embryonic lethal mutations in the flour beetle Tribolium castaneum

Due to its small size, short life cycle, and easy maintenance, the flour beetle Tribolium castaneum is well suited for the genetic analysis of development. One drawback of Tribolium as a genetic system is, however, the difficulty of keeping embryonic lethal lines. Presently, only few lethal mutations can be kept as balanced stocks. Therefore, heterozygous carriers must be identified anew in every generation in order to maintain a recessive embryonic mutation. To alleviate this problem we have devised a block system that allows the simultaneous processing of many mutant lines or test crosses for visual inspection of larval cuticle phenotypes. Using this technique, one person can maintain about 100 embryonic lethal stocks, which makes feasible the thorough genetic analysis of embryogenesis in this species.

Structure and evolution of a pair-rule interaction element: runt regulatory sequences in D. melanogaster and D. virilis

Pair-rule genes serve two important functions during Drosophila development: they first initiate periodic patterns, and subsequently interact with each other to refine these patterns to the precision required for definition of segmental compartments. Previously, we described a pair-rule input region of the runt gene. Here we further characterize this region through the use of reporter gene constructs and by comparison with corresponding sequences from Drosophila virilis. We find that many but not all regulatory properties of this '7-stripe region' are functionally conserved. Moreover, the similarity between these homologous sequences is surprisingly low. When compared to similar data for gap gene input element, our data suggest that pair-rule target sequences are less constrained during evolution, and that functional elements mediating pair-rule interactions can be dispersed over many kilobases.

Pair-rule and gap gene mutants in the flour beetle Tribolium castaneum

Early pattern formation in the Drosophila embryo occurs in a syncytial blastoderm where communication between nuclei is unimpeded by cell walls. During the development of other insects, similar gene expression patterns are generated in a cellular environment. In Tribolium, for instance, pair-rule stripes are transiently expressed near the posterior end of the growing germ band. To elucidate how pattern formation in such a situation deviates from that of Drosophila, functional data about the genes involved are essential. In a genetic screen for Tribolium mutants affecting the larval cuticle pattern, we isolated 4 mutants (from a total of 30) which disrupt segmentation in the thorax and abdomen. Two of these mutants display clear pair-rule phenotypes. This demonstrates that not only the expression, but also the function of pair-rule genes in this short-germ insect is in principle similar to Drosophila. The other two mutants appear to identify gap genes. They provide the first evidence for the involvement of gap genes in abdominal segmentation of short-germ embryos. However, significant differences between the phenotypes of these mutants and those of known Drosophila gap mutants exist which indicates that evolutionary changes occurred in either the regulation or action of these genes.

Regulation of the Tribolium homologues of caudal and hunchback in Drosophila: evidence for maternal gradient systems in a short germ embryo

In short germ embryos, the germ rudiment forms at the posterior ventral side of the egg, while the anterior-dorsal region becomes the extra-embryonic serosa. It is difficult to see how an anterior gradient like that of bicoid in Drosophila could in these embryos be directly involved in patterning of the germ rudiment. Moreover, since it has not yet been possible to recover a bicoid homologue from any species outside the diptera, it has been speculated that the anterior bicoid gradient could be a late addition during insect evolution. We addressed this question by analysing the regulation of potential target genes of bicoid in the short germ embryo of Tribolium castaneum. We demonstrate that homologues of caudal and hunchback from Tribolium are regulated by Drosophila bicoid. In Drosophila, maternal caudal RNA is translationally repressed by bicoid. We find that Tribolium caudal RNA is also translationally repressed by bicoid, when it is transferred into Drosophila embryos under a maternal promoter. This strongly suggests that a functional bicoid homologue must exist in Tribolium. The second target gene, hunchback, is transcriptionally activated by bicoid in Drosophila. Transfer of the regulatory region of Tribolium hunchback into Drosophila also results in regulation by early maternal factors, including bicoid, but in a pattern that is more reminiscent of Tribolium hunchback expression, namely in two early blastoderm domains. Using enhancer mapping constructs and footprinting, we show that caudal activates the posterior of these domains via a specific promoter. Our experiments suggest that a major event in the evolutionary transition from short to long germ embryogenesis was the switch from activation of the hunchback gap domain by caudal to direct activation by bicoid. This regulatory switch can explain how this domain shifted from a posterior location in short germ embryos to its anterior position in long germ insects, and it also suggest how an anterior gradient can pattern the germ rudiment in short germ embryos, i.e. by regulating the expression of caudal.

Disperse versus compact elements for the regulation of runt stripes in Drosophila

The segmented body pattern of the Drosophila embryo is established through a hierarchical network of interacting genes. At each successive step in this pathway, transcriptional regulation is used to convert coarse positional information into finer patterns of gene expression. Central to this process are the cis-regulatory regions that drive the dynamic spatial expression of the different segmentation genes. Here we describe the cis-regulatory region of the runt gene. As found for both other primary pair-rule genes, hairy and even-skipped, there are stripe-specific elements which mediate the initial regulation of runt stripes by gap genes. We did not find autoregulatory elements as described for even-skipped and fushi tarazu. The regulation of runt by other pair-rule genes is mediated by a large region, extending over 5 kb upstream and downstream of the transcription start site. This "disperse" element cannot be subdivided into functionally independent subelements or minimal elements. Such disperse elements mediating pair-rule gene interactions may have escaped detection in other segmentation genes and may involve molecular mechanisms different from those mediating regulation by gap genes.

Regulation of runt transcription by Drosophila segmentation genes

The runt gene plays an important role in the genetic hierarchy that generates the segmented body pattern during the early stages of Drosophila embryogenesis. We studied mRNA expression in mutant embryos in order to investigate the regulation of runt transcription during these stages. We used sensitive whole-mount in situ hybridization procedures to identify the earliest, and therefore most likely direct regulatory effects. There are several distinct phases of runt expression in the early embryo. We find that each phase depends on a different set of regulators. The first phase of expression is a broad-field of mRNA accumulation in the central regions of syncytial blastoderm stage embryos. This pattern is due to terminal repression by the anterior and terminal maternal systems. The effect of the terminal system, even at this early stage, is mediated by two zygotic gap genes, tailless and huckebein. A 7 stripe pattern of runt mRNA accumulation emerges during the process of cellularization. The initial formation of this pattern depends on position-specific repression by zygotic gap genes. Examination of the early RNA patterns of the pair-rule genes even-skipped, hairy, and fushi tarazu indicate that they are also regulated in a similar manner. Three pair-rule genes, hairy, even-skipped, and runt itself, also affect runt's 7 stripe pattern. The effects of runt are stripe specific; the effects of hairy are more uniform; and the patterns obtained in even-skipped mutant embryos show a combination of both stripe specific and uniform regulatory effects. A third distinct phase of expression occurs at the onset of gastrulation when runt becomes expressed in 14 stripes. fushi tarazu plays a negative regulatory role in generating this pattern, whereas the pair-rule genes paired and odd-paired are required for activating or maintaining runt expression during these stages.

Long-term low-dose cyclosporin A in steroid dependent nephrotic syndrome of childhood

Therapy of steroid-dependent idiopathic nephrotic syndrome is often unsatisfactory. Since 1986 we have treated nine children (six male and three female), aged 3-16 years, with cyclosporin A (CsA) during 2.0-5.2 (median 3.1) years. All had minimal change disease on renal biopsy and had previously received cyclophosphamide. Mean daily dosage of CsA was 4.1 mg/kg (range 2.7-5.8) and mean whole blood trough level was 220 ng/ml (range 141-271). The relapse rate decreased from 3.4/patient year before CsA to 0.55 on CsA. Discontinuation of CsA or reduction below 2 mg/kg daily was always followed by a relapse. The overall relapse rate, including the period with very low-dose CsA, was 0.95/patient year. Four patients required additional low-dose alternate-day prednisone. Repeat renal biopsy showed minimal change disease in eight patients and focal segmental glomerulosclerosis in one; CsA-toxicity was mild in two and moderate in one. The latter was the only patient with slightly reduced glomerular filtration rate. Two boys with delayed puberty spontaneously matured and reached expected final height. We conclude that long-term low-dose CsA is very effective and steroid-sparing. Its use is justified in selected patients, particularly in those with numerous relapses and in male patients before and during puberty, as long as renal function and CsA-toxicity are carefully monitored.

Localized requirement for torso-like expression in follicle cells for development of terminal anlagen of the Drosophila embryo

The torso (tor) gene, one of six identified maternal genes essential for the development of the anterior and posterior terminal structures in the Drosophila embryo, is likely to function as a transmembrane receptor tyrosine kinase. Although tor protein is uniformly distributed in the membrane of the egg cell and syncytial embryo, genetic and molecular data suggest that tor is locally activated at the ends of the embryo by a ligand present in the perivitelline space. Local activation of tor could be achieved if the ligand were expressed by a subpopulation of the follicle cells that surround the developing oocyte. Here we describe torso-like (tsl), the sixth member of the terminal gene class, and show that it is unique among these genes in that its expression is required in the somatic follicle cells rather than in the germ line. Moreover, mosaic analysis demonstrates that tsl expression is necessary only in subpopulations of follicle cells located at the poles of the oocyte. Thus, the spatially regulated expression of tsl in the follicle cell layer may generate a localized signal that is transduced by tor, ultimately resulting in the formation of the terminal structures of the embryo.

The organization of the antero-posterior axis

The components specifying the spatial coordinates of the Drosophila embryo are deposited in the egg during oogenesis. Three maternal pathways control the pattern of the embryo along its antero-posterior axis. Genetic and molecular analysis has identified the key-genes in each of these pathways: (1) the bicoid gene encodes an anterior signal in the embryo that directs head and thorax formation via transcriptional activation of anteriorly expressed zygotic genes. (2) A posterior signal, the nanos gene product, antagonizes an inhibitor of abdominal development, hunchback, by translational regulation. (3) A terminal signal controls development at both poles of the embryo. It is probably induced by the somatic follicle cells and transmitted to the embryo via a membrane bound receptor encoded by the gene torso. Other maternal genes function in the localization of these signals or in signal transduction.

Two gap genes mediate maternal terminal pattern information in Drosophila

In Drosophila three maternal pattern organizing activities, the anterior, the posterior, and the terminal, establish the anterior-posterior body pattern of the embryo by initiating the spatially restricted activities of the gap class of zygotic segmentation genes. The activities of tailless (tll) and the newly identified gap gene huckebein (hkb) are specifically involved in mediating the maternal terminal information at the posterior end of the blastoderm embryo.

Function of torso in determining the terminal anlagen of the Drosophila embryo

The formation of the unsegmented terminal regions of the Drosophila larva, acron and telson requires the function of at least five maternal genes (terminal genes class). In their absence, the telson and acron are not formed. One of them, torso (tor), has gain-of-function alleles which have an opposite phenotype to the lack-of-function (tor-) alleles: the segmented regions of the larval body, thorax and abdomen, are missing, whereas the acron is not affected and the telson is enlarged. In strong gain-of-function mutants, the pair-rule gene fushi tarazu (ftz) is not expressed, demonstrating the suppression of the segmentation process in an early stage of development. The tor gain-of-function effect is neutralized, and segmentation is restored in double mutants with the zygotic gene tailless (tll), which has a phenotype similar (but not identical) to that of tor-. This suggests that tor acts through tll, and that in the gain-of-function alleles of tor, the tll gene product is ectopically expressed at middle positions of the embryo, where it inhibits the expression of segmentation genes like ftz.