Predictive preoperative clinical score for patients with liver-only oligometastatic colorectal cancer

Background

Resection of liver metastases from colorectal cancer (CRC) in the oligometastatic stage improves survival and is a potentially curative treatment. Thus, predictive scores that reliably identify those patients who especially benefit from surgery are essential.

Patients and methods

In this multicenter analysis, 512 patients had undergone surgery for liver metastases from CRC. We investigated distinct cancer-specific risk factors that are routinely available in clinical practice and developed a predictive preoperative score using a training cohort (TC), which was thereafter tested in a validation cohort (VC).

Results

Inflammatory response to the tumor, a right-sided primary tumor, multiple liver metastases, and node-positive primary tumor were significant adverse variables for overall survival (OS). Patients were stratified in five groups according to the cumulative score given by the presence of these risk factors. Median OS for patients without risk factors was 133.8 months [95% confidence interval (CI) 81.2-not reached (nr)] in the TC and was not reached in the VC. OS decreased significantly for each subsequent group with increasing number of risk factors. Median OS was significantly shorter (P < 0.0001) for patients presenting all four risk factors: 14.3 months (95% CI 10.5 months-nr) in the TC and 16.6 months (95% CI 14.6 months-nr) in the VC.

Conclusions

Including easily obtainable variables, this preoperative score identifies oligometastatic CRC patients with prolonged survival rates that may be cured, and harbors potential to be implemented in daily clinical practice.

•

We identified four variables of adverse outcome for patients treated with surgical resection of liver metastases from CRC.

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Adverse variables were inflammatory response to the tumor, multiple metastases, right-sided primary tumor, node-positive primary tumor.

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We developed a preoperative clinical score according to the number of risk factors present.

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Using easily obtainable variables, this score identified patients with oligometastatic CRC with good prognosis.

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Patients without risk factors should strongly be considered for surgical resection of their metastases.

TAVI for patients with pulmonary arterial hypertension – impact of the anesthesia regime on the short-term outcome

Objectives and background

Pulmonary Arterial Hypertension (PAH) has been independently associated with increased rates of postoperative heart-failure, hemodynamic instability, respiratory failure and delayed extubation. PAH has been described as a common comorbidity in patients undergoing transfemoral Transcatheter Aortic Valve Implantation (tf-TAVI). Two different anesthetic methods, general anesthesia (TAVI-GA) and conscious sedation (TAVI-S) have become established. Both must be measured by their influence on pulmonary vascular resistance, as all factors worsening PAH have to be avoided. To date, there are no practice guidelines advising the the optimal anesthetic approach for patients with PAH.

Methods

We included all consecutive tf-TAVI patients between 2014 and 2019 in our prospective TAVI registry. A combined endpoint covering the aspects of hemodynamic stability, ventilation and awareness was chosen as primary endpoint. 1. Freedom from catecholaminergic support, 2. Spontaneous breathing and 3. Alertness, defined as GCS &gt;12 points were prerequisite for achieving. PAH was diagnosed by echocardiography immediately before the procedure. The choice for TAVI-GA or TAVI was made by the anesthesiologist.

Results

A total of 1390 patients were included in this analysis. PAH was diagnosed in 74% (n=1031) of the patients. As shown in Tab.1, patients with and without PAH were comparable in terms of pre-procedural comorbidities, blood gas analysis before and after their procedure and procedural data. Postprocedural, a longer stay on ICU was observed in patients with PAH. This was also seen after propensity-score marching. In terms of the primary endpoint, no difference was found between the groups. In addition, the single points catecholaminergic support, spontaneous ventilation and awareness at the time of transfers revealed no difference. Same holds true for secondary endpoints like 30-day mortality, heart failure and adverse procedural events. An analysis based on the choice of anesthesia showed a clear difference in the successful achievement of the primary endpoint. Independent of the presence of PAH, patients undergoing the procedure in TAVI-GA the primary endpoint was less often successfully documented. TAVI-GA patients were more often in need of catecholaminergic support at the end of the procedure and a reduced alertness was more often found.

In patients with PAH and TAVI-GA, a longer length of ICU-stay and a higher incidence of congestive heart failure (CHF) within 30days was found.

Conclusion

Independent of PAH, patients undergoing tf-TAVI in TAVI-GA, were more often in need of catecholaminergic support and less often awake at the end of the procedure. General anesthesia was also more often associated with CHF but not death at 30 days. The achievement of the primary endpoint was independent of the presence of PAH. tf-TAVI can be done under sedation safely in patients with PAH.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): Deutsches Herzzentrum München, Technische Universität München Table 1. Analysis with regard to PAHTable 2. Analysis with regard to Anesth

Early safety outcome in patients requiring conversion to general anesthesia during transfemoral transcatheter aortic valve replacement

Background

Transfemoral TAVR (tf-TAVR) has become an established therapy. Conscious sedation (CS) is a alternative to general anesthesia (GA). So far, the outcome of patients undergoing unplanned conversion from CS to GA has not been investigated.

Methods

All patients undergoing tf-TAVR in CS between 2014 and 2019 were included. Primary endpoint was early safety at 30 days according to VARC-2 criteria. The reasons for conversion and length of ICU-/ hospital-stay were further analyzed.

Results

Of 1058 patients 35 (3.3%) required a conversion. Baseline characteristics were similar among groups. The combined VARC-2 endpoint was documented in 13 (37%) of the converted and 110 (11%) of non-converted patients (p&lt;0.001). Four major sub-groups were underlying causes: unrest in 11/35, procedural complications in 10/35, respiratory distress in 8/35 and cardiovascular decompensation in 6/35 patients. An univariable analysis was performed to identify risk factors for unplanned conversion due to respiratory distress or cardiovascular decompensation (Table). Compared to the group without conversion (Median [IQR], 4 [4–5] days), length of hospital stay was longest in the group with procedural complications (6 [1–11] days) followed by cardiovascular decompensation (5 [4–7] days).

Conclusions

The conversion rate to general anesthesia was overall low but associated with a higher observation of the composite endpoint. Hospital stay was longer dependent on the reason for conversion. A thorough understanding of the frequency, causal factors and clinical significance of unplanned conversion to general anesthesia is of utmost clinical relevance taking a general trend towards a minimalist approach into consideration.

Funding Acknowledgement

Type of funding source: None

Loco-regional recurrence after surgical treatment of oral squamous cell carcinoma: Proposals for follow-up imaging based on literature, national guidelines and institutional experience

The recurrence rate following the treatment of oral squamous cell carcinoma (OSCC) by primary surgery is about 10%-26%. The earliest possible diagnosis of residual tumour, recurrence of local tumour disease, and subsequent metastasis is essential for an improvement of the overall survival and of the survival period for affected patients. No international consensus exists for a post-therapeutic surveillance schedule for OSCCs. Based on a review of the literature, existing guidelines, and our institutional experience, we have established an algorithm for the follow-up of these patients regarding the timing and techniques of postoperative imaging. We recommend a follow-up interval of 6 weeks during the first half-year after discharge from hospital by single clinical and alternating clinical check-ups combined with computed tomography (CT) or magnetic resonance imaging (MRI), followed by an interval of 3 months in the second half-year, with clinical and radiological check-ups. In year 2, we recommend a follow-up interval of 3 months with single clinical and alternating clinical check-ups combined with CT or MRI. In year 3, we recommend screening every 6 months, both clinically and via imaging, because of the decreased risk of recurrence. From year 5 onwards, our recommendation is a clinical and imaging-based examination every 6-12 months, depending on patient risk factors and disease progression. Four standard imaging techniques, namely positron emission tomography (PET), CT, MRI, and ultrasound (US), are discussed concerning their range of application, sensitivity, and specificity. Furthermore, the technical aspects of our institutional protocols are described in detail. In highly frequented head and neck cancer centres, PET and US are of secondary importance, since CT and MRI are nowadays highly efficient tools in primary diagnostic and post-therapeutic surveillance.

Glycaemic control in type II diabetic tube-fed patients with a new enteral formula low in carbohydrates and high in monounsaturated fatty acids: a randomised controlled trial

OBJECTIVES

To investigate the effects of long-term treatment with a new enteral formula low in carbohydrates and high in monounsaturated fatty acids (MUFAs), in comparison with a standard formula, on glycaemic control in tube-fed type II diabetic patients.

DESIGN

Randomised, double-blind, controlled, multi-centre trial.

SETTING

Early rehabilitation centres, primary care and nursing facilities.

SUBJECTS

A total of 78 patients with insulin-treated type II diabetes with HbA(1C) > or =7.0% and/or fasting blood glucose >6.66 mmol/l, who required enteral tube feeding due to neurological dysphagia.

INTERVENTIONS

Patients received 113 kJ (27 kcal)/kg of body weight of either test feed or an isoenergetic, isonitrogenous enteral formula (control) for 12 weeks. Glycaemic control (total daily insulin dosage (IU), fasting blood glucose, and HbA(1C)) and gastrointestinal tolerance were monitored daily.

RESULTS

After 12 weeks, median values for changes from baseline were as follows (test group vs control group, 'data as available' analysis): total daily IUs -6.0 vs 0.0 (P=0.0024), fasting blood glucose (mmol/l) -1.59 vs -0.08 (P=0.0068); HbA(1C) (%) -0.8 vs 0.0 (P=0.0016). Both formulas were tolerated comparably.

CONCLUSIONS

This study indicates that in tube-fed insulin-treated type II diabetic patients, the new low-carbohydrate, high MUFA formula results in a more effective glycaemic control than the standard diet, while being comparable in safety.

Modification of diamond single crystals by chromium ion implantation with sacrificial layers

Single-crystal diamond surfaces were implanted with chromium ions. Ion energies chosen were 120 and 180 keV. Ion doses of 1x10(17) cm(-2) were applied at a substrate temperature of 750 degrees C. Reduced lattice damage could be obtained by deposition of a titanium sacrificial layer with a thickness of 10 and 50 nm before implantation. Depth profiles of the elemental binding states were taken by photoelectron spectroscopy. The effect of the sacrificial layer thickness on diamond lattice damage was investigated by infrared spectroscopy.

A randomized placebo-controlled trial of simethicone and cisapride for the treatment of patients with functional dyspepsia

AIM

To compare the efficacy of simethicone with placebo and the prokinetic cisapride in patients with functional dyspepsia.

METHODS

One hundred and eighty-five patients with functional dyspepsia were randomized and treated in a double-dummy technique with simethicone (105 mg t.d.s.), cisapride (10 mg t.d.s.) or placebo (t.d.s.). The primary outcome measure was the O'Brien global measure of the patients' rating of 10 upper gastrointestinal symptoms (graded as absent = 0, moderate = 1, severe = 2 or very severe = 3). Outcome measures were assessed at baseline and after 2, 4 and 8 weeks of treatment (intention-to-treat).

RESULTS

At 2, 4 and 8 weeks, treatment with simethicone and cisapride yielded significantly (all P values < 0.0001) better improvement of symptoms compared to placebo. Simethicone was significantly better than cisapride after 2 weeks (P = 0.0007), but the differences were not statistically significant after 4 and 8 weeks. Patients treated with simethicone judged the efficacy of their treatment as very good in 46% of cases, compared to 15% and 16% receiving cisapride and placebo, respectively.

CONCLUSIONS

Simethicone and cisapride were significantly better than placebo for symptom control in patients with functional dyspepsia after 2, 4 and 8 weeks of treatment. Simethicone was also superior to the prokinetic cisapride in the first 2 weeks of treatment.

Transient-state and steady-state kinetic studies of the mechanism of NADH-dependent aldehyde reduction catalyzed by xylose reductase from the yeast Candida tenuis

Microbial xylose reductase, a representative aldo-keto reductase of primary sugar metabolism, catalyzes the NAD(P)H-dependent reduction of D-xylose with a turnover number approximately 100 times that of human aldose reductase for the same reaction. To determine the mechanistic basis for that physiologically relevant difference and pinpoint features that are unique to the microbial enzyme among other aldo/keto reductases, we carried out stopped-flow studies with wild-type xylose reductase from the yeast Candida tenuis. Analysis of transient kinetic data for binding of NAD(+) and NADH, and reduction of D-xylose and oxidation of xylitol at pH 7.0 and 25 degrees C provided estimates of rate constants for the following mechanism: E + NADH right arrow over left arrow E.NADH right arrow over left arrow E.NADH + D-xylose right arrow over left arrow E.NADH.D-xylose right arrow over left arrow E.NAD(+).xylitol right arrow over left arrow E.NAD(+) right arrow over left arrow E.NAD(+) right arrow over left arrow E + NAD(+). The net rate constant of dissociation of NAD(+) is approximately 90% rate limiting for k(cat) of D-xylose reduction. It is controlled by the conformational change which precedes nucleotide release and whose rate constant of 40 s(-)(1) is 200 times that of completely rate-limiting E.NADP(+) --> E.NADP(+) step in aldehyde reduction catalyzed by human aldose reductase [Grimshaw, C. E., et al. (1995) Biochemistry 34, 14356-14365]. Hydride transfer from NADH occurs with a rate constant of approximately 170 s(-1). In reverse reaction, the E.NADH --> E.NADH step takes place with a rate constant of 15 s(-1), and the rate constant of ternary-complex interconversion (3.8 s(-1)) largely determines xylitol turnover (0.9 s(-1)). The bound-state equilibrium constant for C. tenuis xylose reductase is estimated to be approximately 45 (=170/3.8), thus greatly favoring aldehyde reduction. Formation of productive complexes, E.NAD(+) and E.NADH, leads to a 7- and 9-fold decrease of dissociation constants of initial binary complexes, respectively, demonstrating that 12-fold differential binding of NADH (K(i) = 16 microM) vs NAD(+) (K(i) = 195 microM) chiefly reflects difference in stabilities of E.NADH and E.NAD(+). Primary deuterium isotope effects on k(cat) and k(cat)/K(xylose) were, respectively, 1.55 +/- 0.09 and 2.09 +/- 0.31 in H(2)O, and 1.26 +/- 0.06 and 1.58 +/- 0.17 in D(2)O. No deuterium solvent isotope effect on k(cat)/K(xylose) was observed. When deuteration of coenzyme selectively slowed the hydride transfer step, (D)()2(O)(k(cat)/K(xylose)) was inverse (0.89 +/- 0.14). The isotope effect data suggest a chemical mechanism of carbonyl reduction by xylose reductase in which transfer of hydride ion is a partially rate-limiting step and precedes the proton-transfer step.

Probing protein stabilization by glycerol using electrospray mass spectrometry

This study shows that electrospray ionization mass spectrometry (ESI-MS), combined with a heated turbo ion-spray interface, allows monitoring protein stabilization by glycerol in solution. Measurements obtained with the two proteins lysozyme and cytochrome c are presented. The observed mass-to-charge (m/z) distributions reveal the stabilizing effect of the additive on the protein conformations against temperature and acid-induced unfolding, as well as against denaturation by acetonitrile. The data obtained with lysozyme allow detection of minor conformational changes upon glycerol addition to the native protein, and suggest that the protein structure in the presence of the additive is slightly compressed compared with its state in water. This result corroborates previous evidence obtained by nuclear magnetic resonance. It is also shown that analysis of the m/z distributions obtained by ESI-MS can lead to detection of partially folded and partially populated states in protein samples.

Structural and functional properties of aldose xylose reductase from the D-xylose-metabolizing yeast Candida tenuis

The primary structure of the aldose xylose reductase from Candida tenuis (CtAR) is shown to be 39% identical to that of human aldose reductase (hAR). The catalytic tetrad of hAR is completely conserved in CtAR (Tyr51, Lys80, Asp46, His113). The amino acid residues involved in binding of NADPH by hAR (D.K. Wilson, et al., Science 257 (1992) 81-84) are 64% identical in CtAR. Like hAR the yeast enzyme is specific for transferring the 4-pro-R hydrogen of the coenzyme. These properties suggest that CtAR is a member of the aldo/keto reductase superfamily. Unlike hAR the enzyme from C. tenuis has a dual coenzyme specificity and shows similar specificity constants for NADPH and NADH. It binds NADP(+) approximately 250 times less tightly than hAR. Typical turnover numbers for aldehyde reduction by CtAR (15-20 s(-1)) are up to 100-fold higher than corresponding values for hAR, probably reflecting an overall faster dissociation of NAD(P)(+) in the reaction catalyzed by the yeast enzyme.

D-Xylose metabolism by Candida intermedia: isolation and characterisation of two forms of aldose reductase with different coenzyme specificities

To study individual enzyme components responsible for the initial step of D-xylose utilisation by the yeast Candida intermedia, a two-step protocol has been developed that enables clear-cut separation and isolation of two structurally similar but functionally different aldose reductases (ALRs) in high yield. In the first step, the yeast cell extract is fractionated efficiently by biomimetic chromatography using the dye HE-3B (reactive Red 120) as pseudoaffinity ligand coupled to Sepharose CL-4B. In the second step, optimised high-resolution anion-exchange chromatography using Mono Q yields purified ALR1 and ALR2 in overall yields of 63 and 62%, respectively. ALR1 is strictly specific for NADPH (2.4 x 10(5) M(-1) s(-1)) whereas ALR2 utilises NADH and NADPH with similar specificity constants of approximately 2-4 x 10(5) M(-1) s(-1). Both enzymes are dimers with a subunit molecular mass of 36000 but they differ in pI and the number of titratable sulphydryl groups in the native protein. The chromatographic procedure identifies microheterogeneity in recombinant aldose reductase from Candida tenuis overexpressed in Escherichia coli.

DNA-binding activity of the transcription factor upstream stimulatory factor 1 (USF-1) is regulated by cyclin-dependent phosphorylation

The ubiquitous transcription factor upstream stimulatory factor (USF) 1 is a member of the bzHLH (leucine zipper-basic-helix-loop-helix) family, which is structurally related to the Myc family of proteins. It plays a role in the regulation of many genes, including the cyclin B1 gene, which is active during the G2/M and M phases of the cell cycle and may also play a role in the regulation of cellular proliferation. We show that the affinity of recombinant USF-1 for DNA is greatly increased by treatment with active cyclin A2-p34(cdc2) or cyclin B1-p34(cdc2) complexes and that its interaction with DNA is dependent on p34(cdc2)-mediated phosphorylation. We have localized the phosphorylation site(s) to a region that lies outside the minimal DNA-binding domain but overlaps with the previously identified USF-specific region. Deletion studies of USF-1 suggest that amino acids 143-197 regulate DNA-binding activity in a phosphorylation-dependent manner.

Binding energy and specificity in the catalytic mechanism of yeast aldose reductases

Derivatives of d-xylose and d-glucose, in which the hydroxy groups at C-5, and C-5 and C-6 were replaced by fluorine, hydrogen and azide, were synthesized and used as substrates of the NAD(P)H-dependent aldehyde reduction catalysed by aldose reductases isolated from the yeasts Candida tenuis, C. intermedia and Cryptococcus flavus. Steady-state kinetic analysis showed that, in comparison with the parent aldoses, the derivatives were reduced with up to 3000-fold increased catalytic efficiencies (k(cat)/K(m)), reflecting apparent substrate binding constants (K(m)) decreased to as little as 1/250 and, for d-glucose derivatives, up to 5.5-fold increased maximum initial rates (k(cat)). The effects on K(m) mirror the relative proportion of free aldehyde that is available in aqueous solution for binding to the binary complex enzyme-NAD(P)H. The effects on k(cat) reflect non-productive binding of the pyranose ring of sugars; this occurs preferentially with the NADPH-dependent enzymes. No transition-state stabilization energy seems to be derived from hydrogen-bonding interactions between enzyme-NAD(P)H and positions C-5 and C-6 of the aldose. In contrast, unfavourable interactions with the C-6 group are used together with non-productive binding to bring about specificity (6-10 kJ/mol) in a series of d-aldoses and to prevent the reaction with poor substrates such as d-glucose. Azide introduced at C-5 or C-6 destabilizes the transition state of reduction of the corresponding hydrogen-substituted aldoses by approx. 4-9 kJ/mol. The total transition state stabilization energy derived from hydrogen bonds between hydroxy groups of the substrate and enzyme-NAD(P)H is similar for all yeast aldose reductases (yALRs), at approx. 12-17 kJ/mol. Three out of four yALRs manage on only hydrophobic enzyme-substrate interactions to achieve optimal k(cat), whereas the NAD(P)H-dependent enzyme from C. intermedia requires additional, probably hydrogen-bonding, interactions with the substrate for efficient turnover.

Randomised double-blind comparison of simethicone with cisapride in functional dyspepsia

AIM

To compare the efficacy of simethicone with cisapride in patients with functional (non-ulcer) dyspepsia.

METHODS

After standardized diagnostic work-up and at least 6-days wash-out of medication, 177 patients with functional dyspepsia were enrolled; 173 of them (age 19-71 years) were randomized and treated using a double-dummy technique with simethicone (84 mg t.d.s.) or cisapride (10 mg t.d.s.). At baseline and after 2 and 4 weeks, the intensity of the symptoms was scored from 0 (absent) to 3 (severe) using a standardized symptom questionnaire. Efficacy of the treatment was judged by the patients as 'very good', 'good', 'moderate' or 'no effect'.

RESULTS

A total of 166 patients completed the trial. After 2 and 4 weeks, 34% and 46% (respectively), of the patients treated with simethicone judged the improvement in symptoms to be excellent compared to 13% and 22% (respectively) of patients treated with cisapride (P < 0.01). After 2 weeks the difference in the improvement in the global symptom score was significantly better (Delta30.7%, P < 0.001) for simethicone than for cisapride, while this difference failed statistical significance after 4 weeks (Delta10.2%, P=0.11).

CONCLUSIONS

In patients with functional dyspepsia, simethicone relieves symptoms during the first 2 weeks of treatment significantly better than cisapride.

Binding and catalysis by yeast aldose reductase: a substrate-analog approach with new aldose derivatives

5-Deoxy-D-xylofuranose derivatives and a range of new 5,6-dideoxy analogs of D-glucofuranose bearing azido or fluoro substituents were synthesised and employed as substrates of the NADH-dependent aldehyde reduction catalysed by yeast aldose reductase. In terms of catalytic efficiencies, these products proved to be superior to the parent compounds.

Evaluation of a novel stable whole blood quality control material for lymphocyte subset analysis: results from the UK NEQAS immune monitoring scheme

The UK NEQAS immune Monitoring Scheme (UK NEQAS) evaluates the performance of laboratories routinely performing T-lymphocyte subset analysis on HIV-infected individuals. The scheme originally issued fresh whole blood, but a significant problem was that of analyte stability, especially 36 h postphlebotomy. To circumvent this problem, we have developed a novel stabilisation procedure that ensures retention of leucocyte light scatter and immunological staining characteristics for up to 300 days. In addition, the stabilised whole blood preparation is fully compatible with flow cytometer technology, incorporating either whole blood lysis or "no wash, no lyse" techniques. The ranges of interlaboratory coefficient of variation for the stabilised material are now tighter than those previously obtained with fresh whole blood. Development of this novel material has enabled overseas laboratories to participate in the UK NEQAS immune Monitoring Scheme and could in the future lead to the production of reference and/or calibration reagents for leucocyte immunophenotyping.

[Severe bacterial infections in gynecology and obstetrics]

Within a 3-years period the presence of nosocomial bacteriaemias was analyzed retrospectively among 13.878 hospitalized patients. The incidence was 0.050%. Antibiotic prophylaxis and the operative technique play an important role in achieving a low incidence of morbidity due to infection. The management of a severe infection includes antibiotic therapy according to culture sensitivity and intensive care.

[Enamel and dentin under the ultrasonic microscope]

Ultrasonic reflection scanning microscopy is a new method for imaging the known structures of dental hard tissues on the basis of a simple specimen preparation. The specimens are scanned in a physiologic humid environment. Particularly high-contrast images are obtained from enamel tufts and lamellae, dentin tubules and interglobular dentin.

[Investigations of the effect and mechanism of action of the beta-sympathomimetic ritodrine on the synthesis and release of dipalmitoyl-lecithin in the fetal rabbit lung (author's transl)]

For a period of 8 days, pregnant white New Zealand rabbits were treated either with the beta-sympathomimetic Ritodrine (1 mg/kg) body weight daily) or with 0.9% saline solution. The fetuses were delivered by caesarian section on the 25th and 30th day of gestation (term being 31 days). No significant difference was found between the Ritodrine and saline treated groups with respect to the levels of dipalmitoyl-lecithin (DPL) obtained from the homogenates as well as the alveolar lavages of the fetal lungs. These results indicate that with this experimental model, prepartum treatment with Ritodrine has no effect either on DPL synthesis or its release into the alveolar spaces. Furthermore, treatment with the beta-sympathomimetic produced no significant change in the concentrations of the specific glucocorticoid receptors in the cytosol and nuclei of the fetal lungs, and in addition, the lung cytosol glucose concentrations as well as the plasma corticosteroid levels were unaffected. These findings support the conclusion that the synthesis of DPL in the fetal lung is not stimulated by Ritodrine.