Association of umbilical vein flow with abnormal fetal growth and adverse perinatal outcome in low-risk population: multicenter prospective study

OBJECTIVE

To investigate the relationship of umbilical vein flow (UVF) measured close to term with abnormal fetal growth and adverse perinatal outcome in a cohort of pregnancies at low risk of placental insufficiency.

METHODS

This was a prospective multicenter observational study conducted across two tertiary maternity units. Patients with a singleton appropriate-for-gestational-age fetus between 35 and 38 weeks' gestation were included. Pregnancies at higher risk of placental insufficiency or with fetal anomalies were excluded. At ultrasound examination, the abdominal circumference (AC), umbilical vein diameter and peak velocity of the umbilical vein were measured, and, using these variables, a new variable, UVF/AC, was calculated. The primary outcome was the occurrence of severely stunted fetal growth, defined as a greater than 40-percentile drop between estimated fetal weight at the third-trimester ultrasound and birth weight. The occurrence of adverse perinatal outcome (defined as one of the following: neonatal acidosis (umbilical artery pH < 7.15 and/or base excess > 12 mmol/L) at birth, 5-min Apgar score < 7, neonatal resuscitation or neonatal intensive care unit admission) was analyzed as a secondary outcome.

RESULTS

Between April 2021 and March 2023, 365 women were included in the study. The mean UVF/AC at enrolment was 6.4 ± 2.6 mL/min/cm, and 35 (9.6%) cases were affected by severely stunted fetal growth. Severely stunted fetal growth was associated with a lower mean UVF/AC (5.4 ± 2.6 vs 6.5 ± 2.6 mL/min/cm; P = 0.02) and a higher frequency of UVF/AC < 10th percentile (8/35 (22.9%) vs 28/330 (8.5%); P = 0.01). Moreover, UVF/AC showed an area under the receiver-operating-characteristics curve (AUC) of 0.65 (95% CI, 0.55-0.75; P = 0.004) in predicting the occurrence of severely stunted fetal growth, and the optimal cut-off value of UVF/AC for discriminating between normal and severely stunted fetal growth was 7.2 mL/min/cm. This value was associated with a sensitivity and specificity of 0.77 (95% CI, 0.60-0.90) and 0.33 (95% CI, 0.28-0.39), and positive and negative predictive values of 0.11 (95% CI, 0.07-0.15) and 0.93 (95% CI, 0.87-0.97), respectively. Regarding the occurrence of adverse perinatal outcome, this was associated independently with maternal age (adjusted odds ratio (aOR), 0.93 (95% CI, 0.87-0.99); P = 0.04), UVF/AC Z-score (aOR, 0.53 (95% CI, 0.30-0.87); P = 0.01) and augmentation of labor (aOR, 2.69 (95% CI, 1.28-5.69); P = 0.009). UVF/AC showed an AUC of 0.65 (95% CI, 0.56-0.73; P = 0.005) in predicting the occurrence of adverse perinatal outcome, and the optimal cut-off value of UVF/AC for discriminating between normal and adverse perinatal outcome was 6.7 mL/min/cm. This value was associated with a sensitivity and specificity of 0.70 (95% CI, 0.54-0.83) and 0.40 (95% CI, 0.34-0.45), and positive and negative predictive values of 0.14 (95% CI, 0.09-0.19) and 0.91 (95% CI, 0.85-0.95), respectively.

CONCLUSIONS

Our data demonstrate an association between reduced UVF close to term, severely stunted fetal growth and adverse perinatal outcome in a cohort of low-risk pregnant women, with a moderate ability to rule out and a poor ability to rule in either outcome. Further studies are needed to establish whether the assessment of UVF can improve the identification of fetuses at risk of subclinical placental insufficiency and adverse perinatal outcome. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Mode of delivery and peripartum outcome in women with heart disease according to the ESC guidelines: an Italian multicenter study

INTRODUCTION

The European Society of Cardiology (ESC) guidelines (GL) provide indications on the mode of delivery in women with heart disease. However available data suggests that the rate of Cesarean Delivery (CD) is high and widely variable among such patients. In this study, we aimed to investigate the degree of adherence to the ESC recommendations among women delivering in four tertiary maternity services in Italy and how this affects the maternal and neonatal outcomes.

MATERIAL AND METHODS

Retrospective multicenter cohort study including pregnant women with heart disease who gave birth between January 2014 and July 2020. Composite adverse maternal outcome (CAM) was defined by the occurrence of one or more of the following: major postpartum hemorrhage, thrombo-embolic or ischemic event, de novo arrhythmia, heart failure, endocarditis, aortic dissection, need for re-surgery, sepsis, maternal death. Composite Adverse Neonatal outcome (CAN) was defined as cord arterial pH <7.00, APGAR <7 at 5 min, admission to the intensive care unit, and neonatal death. We compared the incidence of CAM and CAN between the cases with planned delivery in accordance (group "ESC consistent") or in disagreement (group "ESC not consistent") with the ESC GL.

RESULTS

Overall, 175 women and 181 liveborn were included. A higher frequency of CAN was found when delivery was not planned accordingly to the ESC guidelines [("ESC consistent" 9/124 (7.2%) vs "ESC not consistent" 13/57 (22.8%) p = 0.002 OR 3.74 (CI 95% 1.49-9.74) , while the occurrence of CAM was comparable between the two groups. At logistic regression analysis, the gestational age at delivery was the only parameter independently associated with the occurrence of CAN (p = 0.006).

CONCLUSION

Among pregnant women with heart disease, deviating from the ESC guidelines scheduling cesarean delivery does not seem to improve maternal outcomes and it is associated with worse perinatal outcomes, mainly due to lower gestational age at birth.

A case of postpartum headache post dural puncture. Post Dural Puncture Headache or Reversible Cerebral Vasoconstriction Syndrome - Posterior Reversible Encephalopathy Syndrome?

Background and aim:

Reversible Cerebral Vasoconstriction Syndrome (RCVS) and Posterior Reversible Encephalopathy Syndrome (PRES) are two rare neurological conditions, clinically characterized by headache. In our case a diagnosis of PDPH was made though imaging showed signs of RCVS-PRES.

Methods:

We present a case of RCVS-PRES in a postpartum woman who presented headache as first symptom and only later experienced seizures. Dural puncture worked as a confounding factor in the clinical postpartum evaluation.

Results-Conclusions:

We want to focus the attention on changes of clinical characteristics of headache as an important factor to be analysed, in order to have a prompt diagnosis. We therefore propose a diagnostic algorithm. Moreover, we evaluate possible triggers of RCVS and PRES; in our case dural puncture is probably not the trigger, in fact there were no liquoral hypotension signs on imaging.

Hemodynamic findings in normotensive women with small-for-gestational-age and growth-restricted fetuses

INTRODUCTION

Fetal growth restriction (FGR) in most instances is a consequence of primary placental dysfunction due to inadequate trophoblastic invasion. Maternal cardiac maladaptation to pregnancy has been proposed as a possible determinant of placental insufficiency and impaired fetal growth. This study aimed to compare the maternal hemodynamic parameters between normotensive women with small-for-gestational-age (SGA) and FGR fetuses and to evaluate their correlation with neonatal outcome.

MATERIAL AND METHODS

An observational cohort study including singleton pregnancies referred to our tertiary care center due to fetal smallness. At the time of diagnosis, fetuses were classified as SGA or FGR according to the Delphi consensus criteria, and pregnant women underwent hemodynamic assessment using a cardiac output monitor. A group of women with singleton uncomplicated pregnancies ar ≥35 weeks of gestation were recruited as controls. Cardiac output, systemic vascular resistance, stroke volume, and heart rate were measured and compared among the three groups (controls vs FGR vs SGA). The correlation between antenatal findings and neonatal outcome was also evaluated by multivariate logistic regression analysis.

RESULTS

A total of 51 women with fetal smallness were assessed at 34.8 ± 2.6 weeks. SGA and FGR were diagnosed in 22 and 29 cases, respectively. The control group included 61 women assessed at 36.5 ± 0.8 weeks of gestation. Women with FGR had a lower cardiac output Z-score (respectively, -1.3 ± 1.2 vs -0.4 ± 0.8 vs -0.2 ± 1.0; P < .001) and a higher systemic vascular resistance Z-score (respectively, 1.2 ± 1.2 vs 0.2 ± 1.1 vs -0.02 ± 1.2; P < .001) compared with both SGA and controls, whereas no difference in the hemodynamic parameters was found between women with SGA and controls. The incidence of neonatal intensive care unit admission did not differ between SGA and FGR fetuses (18.2% vs 41.4%; P = .13), but FGR fetuses had a longer hospitalization compared with SGA fetuses (14.2 ± 17.7 vs 4.5 ± 1.6 days; P = .02). Multivariate analysis showed that the cardiac output Z-score at diagnosis (P = .012) and the birthweight Z-score (P = .007) were independent predictors of the length of neonatal hospitalization.

CONCLUSIONS

Different maternal hemodynamic profiles characterize women with SGA or FGR fetuses. Furthermore, a negative correlation was found between the maternal cardiac output and the length of neonatal hospitalization.

New technique for automatic sonographic measurement of change in head-perineum distance and angle of progression during active phase of second stage of labor

OBJECTIVE

To evaluate the performance of a new ultrasound technique for the automatic assessment of the change in head-perineum distance (delta-HPD) and angle of progression (delta-AoP) during the active phase of the second stage of labor.

METHODS

This was a prospective observational cohort study including singleton term pregnancies with fetuses in cephalic presentation during the active phase of the second stage of labor. In each patient, two videoclips of 10 s each were acquired transperineally, one in the axial and one in the sagittal plane, between rest and the acme of an expulsive effort, in order to measure HPD and AoP, respectively. The videoclips were processed offline and the difference between the acme of the pushing effort and rest in HPD (delta-HPD) and AoP (delta-AoP) was calculated, first manually by an experienced sonographer and then using a new automatic technique. The reliability of the automatic algorithm was evaluated by comparing the automatic measurements with those obtained manually, which was considered as the reference gold standard.

RESULTS

Overall, 27 women were included. A significant correlation was observed between the measurements obtained by the automatic and the manual methods for both delta-HPD (intraclass correlation coefficient (ICC) = 0.97) and delta-AoP (ICC = 0.99). The high accuracy provided by the automatic algorithm was confirmed by the high values of the coefficient of determination (r²  = 0.98 for both delta-HPD and delta-AoP) and the low residual errors (root mean square error = 1.2 mm for delta-HPD and 1.5° for delta-AoP). A Bland-Altman analysis showed a mean difference of 0.52 mm (limits of agreement, -1.58 to 2.62 mm) for delta-HPD (P = 0.034) and 0.35° (limits of agreement, -2.54 to 3.09°) for delta-AoP (P = 0.39) between the manual and automatic measurements.

CONCLUSIONS

The automatic assessment of delta-AoP and delta-HPD during maternal pushing efforts is feasible. The automatic measurement of delta-AoP appears to be reliable when compared with the gold standard manual measurement by an experienced operator. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

A Case of Postpartum Headache Post Dural Puncture. Post Dural Puncture Headache or Reversible Cerebral Vasoconstriction Syndrome - Posterior Reversible Encephalopathy Syndrome? [DOI: 10.21203/rs.3.rs-60146/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

BACKGROUNDReversible Cerebral Vasoconstriction Syndrome (RCVS) and Posterior Reversible Encephalopathy Syndrome (PRES) are two rare neurological conditions, clinically characterized of headache. This is sometimes difficult to differentiate from post dural puncture headache (PDPH). In our case a diagnosis of PDPH was made but imaging showed signs of RCVS-PRES. The novelty is that, unlike in cases reported in literature, no liquoral hypotension signs were detected on imaging.CASE PRESENTATIONWe present a case of RCVS-PRES in a postpartum woman that presented headache as first symptom, and only later experienced seizures. Epidural analgesia was performed during labour, and it was complicated by dural puncture that worked as a confounding factor in the clinical postpartum evaluation. Seizures represented an unexpected event in the course of treating this patient for post dural puncture headache.CONCLUSIONSWe point out the attention on changes of clinical characteristics of headache as an important factor to be analyzed, in order to have a prompt diagnosis. Moreover, we evaluate possible triggers of RCVS and PRES; in our case dural puncture is probably not the trigger, in fact there were no liquoral hypotension signs on imaging. According to literature reports, puerperium itself was a promoting factor.

Automatic measurement of head-perineum distance during intrapartum ultrasound: description of the technique and preliminary results

OBJECTIVES

To evaluate the accuracy and reliability of a new ultrasound technique for the automatic assessment of the head-perineum distance (HPD) during childbirth.

METHODS

HPD was measured on a total of 40 acquisition sessions in 30 laboring women both automatically by an innovative algorithm and manually by trained sonographers, assumed as gold standard.

RESULTS

A significant correlation was found between manual and automatic measurements (Intra-CC = 0.994). High values of the coefficient of determination (r²=0.98) and low residual errors: RMSE = 2.01 mm (4.9%) were found.

CONCLUSION

The automatic algorithm for the assessment of the HPD represents a reliable technique.

Determinants of neonatal hypoglycemia after antenatal administration of corticosteroids (ACS) for lung maturation: Data from two referral centers and review of the literature

BACKGROUND

A correlation between ACS and neonatal hypoglycemia has been recently demonstrated.

AIMS

The aim of the study was to evaluate the determinants of neonatal hypoglycemia in women exposed to ACS for respiratory distress syndrome prevention.

MATERIAL AND METHODS

Retrospective, multicenter, cohort study conducted in two Tertiary University Units. All fetuses delivered from 2016 to 2017 after ACS (two doses i.m. of Betamethasone 12 mg 24 h apart) were considered eligible for the study purpose. The primary outcome was the incidence of hypoglycemia, defined as a glycemic value ≤45 mg/dl within the first 48 h of neonatal life. The effect on neonatal glycaemia due to timing (interval from exposure to delivery) and type (single completed, single partial or repeated course) of ACS administration was also assessed.

RESULTS

Overall, 99 neonates met the inclusion criteria. Hypoglycemia occurred in 38/99 (38.4%) of the included newborns. Compared to normoglycemic neonates, those with hypoglycemia had lower gestational age at delivery (33.06 ± 3.37 vs. 35.94 ± 3.17 g; p < 0.0001). Lower birthweight (1747.28 ± 815.29 vs. 2499.24 ± 780.51 g; p < 0.0001), a shorter interval time from administration to delivery (1.85 ± 2.59 vs. 3.34 ± 3.39 weeks; p = 0.02) and a higher incidence of single partial course (23.7 vs. 8.72%; p = 0.03). Multivariate logistic regression found that only birthweight was significantly associated with neonatal hypoglycemia (OR 0.4 95% CI -1.16/-0.04; p < 0.038).

CONCLUSION

Hypoglycemia occurs in a large proportion of fetuses exposed to ACS independently from the type of exposure (single partial/single completed) and from the time interval between ACS administration and delivery. Birthweight seems to be the strongest determinant for the occurrence neonatal hypoglycemia after antenatal administration of steroids for lung maturation.

Evaluation of the uterine scar stiffness in women with previous Cesarean section by ultrasound elastography: A cohort study

PURPOSE

To evaluate by means of elastography if the quantitative assessment of the cesarean scar elasticity is feasible using as reference the surrounding intact myometrium and to investigate if the cesarean scar stiffness is influenced by the clinical characteristics of the previous cesarean delivery.

METHODS

Prospective study including women with a previous Cesarean Section (CS) ≥ 37 weeks' gestation performed 12-15 months before. By transvaginal ultrasound two regions of interest (ROI) were selected: uterine scar (Region 1) and surrounding myometrium (Region 2). Strain index (SI) for each ROI was calculated and the Strain Ratio (SR) was defined as Region 1 SI/Region 2 SI. The primary outcome was to compare SR among women who were grouped in accordance to presence of previous vaginal delivery, CS during labor, type of suture or pyrexia during post-partum. The secondary outcome of this study was to evaluate the correlation between SR and maternal, neonatal and labor characteristics.

RESULTS

68 women were included. The mean SR was 1.8 ± 0.7 thus indicating an increased stiffness of the uterine scar compared to the surrounding myometrium. No significant differences were found in terms of SR according to presence of previous VD, CS during labor, type of suture or pyrexia during post-partum period. Strain Ratio was not correlated to maternal characteristics nor to labor and neonatal outcome.

CONCLUSIONS

Evaluation of uterine scar stiffness is feasible by using elastography. The stiffness of the uterine scar is higher than that of the surrounding myometrium and is not correlated to maternal and labor characteristics.

Maternal cardiac parameters can help in differentiating the clinical profile of preeclampsia and in predicting progression from mild to severe forms

BACKGROUND

A primary role of maternal heart dysfunction in the pathophysiology of preeclampsia had been previously advocated although if contradictory results have been reported.

OBJECTIVES

The objectives of the study were to describe maternal hemodynamic parameters according to 2 main preeclampsia phenotypes and to investigate whether cardiac findings may be helpful in characterizing the severity and the progression of the disease.

STUDY DESIGN

This was a prospective cohort study. We used an ultrasonic cardiac output monitor system to compare the hemodynamic parameters of women with preeclampsia with a group of healthy normotensive women enrolled as controls with a ratio of 1:2. Cardiac output, systemic vascular resistance, and stroke volume were compared among controls and preeclamptic women who were grouped in accordance to the following characteristics: early preeclampsia (<34 weeks' gestation) vs late preeclampsia onset (≥34 weeks' gestation); preeclampsia associated with appropriate for gestational age or small-for-gestational-age newborns. Hemodynamic characteristics were also compared between preeclamptic women with a mild form vs those who progressed toward a severe form.

RESULTS

A total of 38 preeclamptic women and 61 normotensive women were included in the study. Both cases of preeclampsia associated with small-for-gestational-age neonates as those with normal-sized ones showed higher systemic vascular resistance compared with the control group (respectively, 1580.6 ± 483.2 vs 1479.1 ± 433.3 vs 1105.3 ± 293.1; P < .0001), while a lower cardiac output was reported only for preeclamptic women with small-for-gestational-age neonates compared with controls (5.7 ± 1.5 vs 6.5 ± 1.3; P = .02). Maternal cardiac parameters were comparable between these 2 groups of preeclamptic women (small-for-gestational-age vs appropriate-for-gestational-age preeclampsia) with the exception of a lower stroke volume in the former one (64.8 ± 24.4 vs 75.2 ± 17.8; P = .04). Similarly, women with both early and late preeclampsia showed higher systemic vascular resistance compared with controls (1559.5 ± 528.3 vs 1488.5 ± 292.9 vs 1105.3 ± 293.1, respectively; P < .001), while a lower cardiac output was noted only in the early-onset group compared with controls (5.5 ± 1.2 P = .02). Maternal cardiac findings were similar between women with early vs late-onset preeclampsia. Hemodynamic parameters are significantly different between those women with mild preeclampsia who remained stable compared with those who progressed toward a severe disease. Cardiac output Z-score, systemic vascular resistance Z-score, and uterine arteries' pulsatility index Z-score showed similar sensitivity (80% vs 75% vs 80%, respectively) and specificity (73% vs. 73% vs 74%, respectively), while the association of systemic vascular resistance Z-score and uterine arteries pulsatility index Z-score showed a sensitivity of 95% and a specificity of 80% (area under the curve, 0.90) in predicting evolution toward severe forms.

CONCLUSION

Evaluation of maternal cardiovascular system could help clinician in defining a subset of preeclamptic patients with more profound placental impairment and might predict the likelihood of progression toward a severe condition in cases with a mild preeclampsia at clinical onset.

Prediction of spontaneous vaginal delivery in nulliparous women with a prolonged second stage of labor: the value of intrapartum ultrasound

BACKGROUND

A limited number of studies have addressed the role of intrapartum ultrasound in the prediction of the mode of delivery in women with prolonged second stage of labor.

OBJECTIVE

The objective of the study was to evaluate the role of transabdominal and transperineal sonographic findings in the prediction of spontaneous vaginal delivery among nulliparous women with prolonged second stage of labor.

STUDY DESIGN

This was a 2-center prospective study conducted at 2 tertiary maternity units. Nulliparous women with a prolonged active second stage of labor, as defined by active pushing lasting more than 120 minutes, were eligible for inclusion. Transabdominal ultrasound to evaluate the fetal head position and transperineal ultrasound for the measurement of the midline angle, the head-perineum distance, and the head-symphysis distance were performed in between uterine contractions and maternal pushes. At transperineal ultrasound the angle of progression was measured at rest and at the peak of maternal pushing effort. The delta angle of progression was defined as the difference between the angle of progression measured during active pushing at the peak of maternal effort and the angle of progression at rest. The sonographic findings of women who had spontaneous vaginal delivery vs those who required obstetric intervention, either vacuum extraction or cesarean delivery, were evaluated and compared.

RESULTS

Overall, 109 were women included. Spontaneous vaginal delivery and obstetric intervention were recorded in 40 (36.7%) and 69 (63.3%) patients, respectively. Spontaneous vaginal delivery was associated with a higher rate of occiput anterior position (90% vs 53.2%, P < .0001), lower head-perineum distance and head-symphysis distance (33.2 ± 7.8 mm vs 40.1 ± 9.5 mm, P = .001, and 13.1 ± 4.6 mm vs 19.5 ± 8.4 mm, P < .001, respectively), narrower midline angle (29.6° ± 15.3° vs 54.2° ± 23.6°, P < .001) and wider angle of progression at the acme of the pushing effort (153.3° ± 19.8° vs 141.8° ± 25.7°, P = .02) and delta-angle of progression (17.3° ± 12.9° vs 12.5° ± 11.0°, P = .04). At logistic regression analysis, only the midline angle and the head-symphysis distance proved to be independent predictors of spontaneous vaginal delivery. More specifically, the area under the curve for the prediction of spontaneous vaginal delivery was 0.80, 95% confidence interval (0.69-0.92), P < .001, and 0.74, 95% confidence interval (0.65-0.83), P = .002, for the midline angle and for the head-symphysis distance, respectively.

CONCLUSION

Transabdominal and transperineal intrapartum ultrasound parameters can predict the likelihood of spontaneous vaginal delivery in nulliparous women with prolonged second stage of labor.

Prototype of a drought monitoring and forecasting system for the Tuscany region

Abstract. A system for drought monitoring and medium–long time forecasting in the Tuscany region (central Italy) is briefly introduced, which is based on ground and satellite data (1 km spatial resolution and 16-day temporal resolution). It is also shown how information about current conditions and future evolution of a drought event is periodically delivered on the LaMMA Consortium website, in collaboration with the Institute of Biometeorology (IBIMET-CNR).

Impact of environmental changes and human-related factors on the potential malaria vector, Anopheles labranchiae (Diptera: Culicidae), in Maremma, Central Italy

The Maremma Plain (central Italy) was hyper-endemic for malaria until the mid-20th century, when a national campaign for malaria elimination drastically reduced the presence of the main vector Anopheles labranchiae Falleroni. However, the introduction of rice cultivation over 30 yr ago has led to an increase in the An. labranchiae population and concern over possible malaria reemergence. We studied the impact of anthropogenic environmental changes on the abundance and distribution of An. labranchiae in Maremma, focusing on rice fields, the main breeding sites. Adults and larvae were collected in three main areas with diverse ecological characteristics. Data were collected on human activity, land use, and seasonal climatic and demographic variations. We also interviewed residents and tourists regarding their knowledge of malaria. Our findings showed that the most important environmental changes have occurred along the coast; An. labranchiae foci are present throughout the area, with massive reproduction strictly related to rice cultivation in coastal areas. Although the abundance of this species has drastically decreased over the past 30 yr, it remains high and, together with climatic conditions and the potential introduction of gametocyte carriers, it may represent a threat for the occurrence of autochthonous malaria cases. Our findings suggest the need for the continuous monitoring of An. labranchiae in the study area. In addition to entomological surveillance, more detailed knowledge of human-induced environmental changes is needed, so as to have a more complete database that can be used for vector-control plans and for properly managing emergencies related to autochthonous introduced cases.

[Dermatofibrosarcoma protuberans: surgical treatment using the Tübingen technique (31 cases)]

BACKGROUND

Dermatofibrosarcoma protuberans is a rare cutaneous sarcoma that progresses slowly. Although it exhibits pronounced local aggressiveness, it rarely metastasises. The condition is difficult to treat on account of asymmetric and unpredictable growth as well as the frequency of relapse. Treatment is primarily surgical.

PATIENTS AND METHODS

We report 31 cases of dermatofibrosarcoma protuberans operated at the Dermatology Clinic of Novara between 1997 and 2004 using the Tübingen technique. An immunohistochimical study was performed and screening was carried out for possible extension of the neoplasm into muscle.

RESULTS

Muscular involvement was seen in 4 cases. No relapses were seen over a median survival period of 3 years and no patients were lost to follow-up.

DISCUSSION

The Mohs technique is the surgical method of reference and allows tumour eradication with sparing of healthy tissue. The Tübingen method constitutes an alternative approach requiring fewer histological sections. The results obtained in our series were good and no relapses were seen over a median survival period of 3 years.

Computational Studies of Competitive Inhibitors of Nitric Oxide Synthase (NOS) Enzymes: Towards the Development of Powerful and Isoform-Selective Inhibitors

Crystallographic structures of wild-type and mutant NOS isoforms complexed with substrate, intermediate, inhibitor, cofactor, and cofactor analogs are currently available. However, because of the high level of amino-acid conservation and the consequent similarity in dimeric quaternary structure as well as in the active site of NOS isoforms, structure-based isoform-selective inhibitor design is still a very challenging task. Nevertheless, the comprehension of the structural determinants for selectivity among the isoforms is fundamental for the design of further potent and more selective inhibitors. Computational techniques, based on the knowledge of the tridimensional structure of the isozymes, have been already applied to understand the significant isoform selectivity shown by some compounds. Collectively these structure-based approaches, in combination with SAR studies, have been able to explain the structural reasons of this selectivity.