Ac-EAZY! Towards GMP-Compliant Module Syntheses of 225Ac-Labeled Peptides for Clinical Application.

The application of 225Ac (half-life T1/2 = 9.92 d) dramatically reduces the activity used for peptide receptor radionuclide therapy by a factor of 1000 in comparison to 90Y, 177Lu or 188Re while maintaining the therapeutic outcome. Additionally, the range of alpha particles of 225Ac and its daughter nuclides in tissue is much lower (47-85 µm for alpha energies Eα = 5.8-8.4 MeV), which results in a very precise dose deposition within the tumor. DOTA-conjugated commercially available peptides used for endoradiotherapy, which can readily be labeled with 177Lu or 90Y, can also accommodate 225Ac. The benefits are lower doses in normal tissue for the patient, dose reduction of the employees and environment and less shielding material. The low availability of 225Ac activity is preventing its application in clinical practice. Overcoming this barrier would open a broad field of 225Ac therapy. Independent which production pathway of 225Ac proves the most feasible, the use of automated synthesis and feasible and reproducible patient doses are needed. The Modular-Lab EAZY is one example of a GMP-compliant system, and the cassettes used for synthesis are small. Therefore, also the waste after the synthesis can be minimized. In this work, two different automated setups with different purification systems are presented. In its final configuration, three masterbatches were performed on the ML EAZY for DOTA-TATE and PSMA-I&T, respectively, fulfilling all quality criteria with final radiochemical yields of 80-90% for the 225Ac-labeled peptides.

Comparison of (90)Y activity measurements in nuclear medicine in Germany.

In 2014, PTB and the company Eckert & Ziegler organized a national comparison exercise to determine the activity of a (90)Y solution. One aim of the comparison was to assess the measurement capability of hospitals and medical practices in Germany. P6-type vials were filled with aliquots of a radioactive (90)Y solution and then sent to 19 participants who were asked to measure the activity in the ampoules as well as in their own standard geometry using syringes. Most of the submitted results have a deviation of less than ±10% from the PTB reference activity when measured in the P6-type vials. The spread is somewhat larger when measured in a syringe geometry. The comparison revealed that some participants have difficulties in applying decay corrections and only a few participants were capable of estimating realistic measurement uncertainties.

Main bronchus occlusion for treatment of congenital diaphragmatic hernia in fetal lambs.

PURPOSE: The present study investigates a new surgical approach in the treatment of left diaphragmatic hernia in fetal sheep. We postulated that unlike tracheal occlusion where both lungs are occluded, selective left main bronchus occlusion (LMBO) would accelerate growth of only the left lung, reduce left visceral herniation, and recover space in the both thoraces necessary for lung development. METHODS: Left-sided congenital diaphragmatic hernia (CDH) was surgically created in 8 fetal lambs at approximately 65 days of gestation; in 4 of these animals, LMBO was performed at approximately 118 days. Four sham-operated animals served as controls. Lambs were delivered by hysterotomy at 137 days. We measured lung-to-body weight ratios, alveolar surface area, septal wall thickness, and AE2 cell density in the left and right lungs. RESULTS: Left main bronchus occlusion increased (P < .05) left lung growth causing severe right mediastinal shift but failed to reduce herniated abdominal viscera in 3 of 4 lambs. Wet lung-to-body weight ratio in LMBO group was similar to that of the control group; however, this was achieved by overgrowth of left lung, whereas the right wet lung-to-body weight ratio remained low. In the LMBO group, right lung AE2 cell density was higher than that of control group and not different to that of the CDH group. CONCLUSIONS: Left main bronchus occlusion failed to restore normal pulmonary development in CDH.

Prenatal glucocorticoids improve lung morphology and partially restores surfactant mRNA expression in lambs with diaphragmatic hernia undergoing fetal tracheal occlusion.

In fetal sheep with surgically created diaphragmatic hernia (DH), tracheal occlusion (TO) can restore lung growth but does not ameliorate the increase in inter-alveolar wall thickness (T(W)). We determined whether prenatal exposure to glucocorticoids (GC) could reduce T(w) in fetuses with DH undergoing TO. At 65 days of gestation, DH was created in 12 fetal sheep, and TO subsequently performed at 110 days (DH/TO). Six of these fetuses were exposed to betamethasone (DH/TO + GC; 0.5 mg/kg; maternal, IM) 48 hr before delivery; Sham operated fetuses (n = 7) served as controls. At 139 days, we measured alveolar surface density (S(V)), parenchymal tissue fraction, T(W), alveolar type 2 (AE2) cell density and lung surfactant protein (SP) mRNA expression. Prenatal GC decreased T(W) and S(V) by 33% and 27% respectively, and increased fixed lung volume (by 55%), AE2 cell density and partially restored SPmRNA expression. Our data indicate that prenatal exposure to GC can reverse some of the negative effects of prolonged fetal TO. We hypothesize that a GC-induced reduction in lung liquid volume during TO contributes, in part, to the observed increase in AE2 cell density and SPmRNA expression.

Prenatal glucocorticoids and exogenous surfactant therapy improve respiratory function in lambs with severe diaphragmatic hernia following fetal tracheal occlusion.

Fetal tracheal occlusion (TO) accelerates lung growth and can reverse severe lung hypoplasia associated with diaphragmatic hernia (DH), however, lung compliance (Cl) and respiratory gas exchange remain abnormal. We determined the individual and combined effects of prenatal glucocorticoids (GC) and exogenous surfactant therapy (S) on postnatal pulmonary function in lambs with DH that underwent prolonged TO. DH was created in 22 fetal sheep at 65 d of gestation and TO performed at 110 d. Eleven DH/TO animals received prenatal GC (betamethasone, 0.5 mg/kg) 48 h before delivery; six GC-treated and five non-GC lambs were administered surfactant (Infasurf, 3 mg/kg) at birth. Six sham-operated lambs served as controls. Lambs were delivered at 139 d gestation and ventilated for 2 h. GC or surfactant therapy alone significantly improved respiratory gas exchange, Cl, and ventilatory efficiency index. Total lung capacity was normalized only in DH/TO lambs that received both GC and S.

Tracheal occlusion in fetal rats alters expression of mesenchymal nuclear transcription factors without affecting surfactant protein expression.

BACKGROUND/PURPOSE: Mesenchymal nuclear transcription factors (MNTF) are involved in lung development and maturation and regulate surfactant protein (SP) expression. Prolonged (>2 weeks) fetal tracheal occlusion (TO) has been shown to accelerate lung growth and inhibit pulmonary surfactant synthesis. The effects of TO on SP expression and MNTF, however, have not been formally assessed. The objectives of this study were to evaluate the effects of short-term (3 days) TO on normal lung growth and protein expression of pulmonary MNTF involved in SP synthesis. METHODS: At E19 (term, 22 days), 2 fetuses per time-dated Sprague-Dawley rats underwent either TO (n = 23) or a sham (n = 22) operation. Lungs were harvested 72 hours post surgery. Pulmonary SP-A; SP-B; SP-C messenger RNA (mRNA) expression; and SP-A and SP-B, Hoxb5, thyroid transcription factor 1, and retinoic X receptor-alpha protein expression were analyzed. RESULTS: Lung weight was significantly increased by TO (TO 0.32 +/- 0.02g vs SHAM 0.14 +/- 0.01 g; P < .001), resulting in 123% increase of the lung-to-body-weight ratio. No difference of SP-A-mRNA (177 +/- 4.3 TO vs 169 +/- 4.4 SHAM; P = .25), SP-B-mRNA (87.7 +/- 0.2 TO vs 87.4 +/- 0.02 SHAM; P = .33), and SP-C-mRNA (186.5 +/- 3.2 TO vs 183.2 +/- 2.7 SHAM; P = .45) expression was found. Surfactant protein A (175.6 +/- 25.3 TO vs 192.5 +/- 19.8 SHAM; P = .59) and SP-B (163.4 +/- 5.2 TO vs 166.8 +/- 9.3 SHAM; P = .75) protein expression were similar in both groups; however, Hoxb5 (70.3 +/- 18.9 TO vs 130.6 +/- 5.1 SHAM; P = .02) and thyroid transcription factor 1 (102.6 +/- 19 TO vs 181.1 +/- 6.3 SHAM; P = .007) expression were significantly decreased. Retinoic X receptor-alpha expression tended to be increased by TO (171.9 +/- 6.0 TO vs 155.4 +/- 6.7 SHAM; P = .06). CONCLUSIONS: Short-term TO late in gestation induces rapid lung growth. Surfactant protein-mRNA and protein expression are not significantly altered. Thyroid transcription factor 1 and Hoxb5 are down-regulated by TO, suggesting that duration and timing of occlusion are important in balancing the effects of TO on lung growth vs lung maturation.

Surfactant protein expression is increased in the ipsilateral but not contralateral lungs of fetal sheep with left-sided diaphragmatic hernia.

Congenital diaphragmatic hernia (CDH) impairs fetal lung growth and increases the density of alveolar epithelial type 2 (AE2) cells. There is controversy whether surfactant protein (SP) expression is altered in CDH. The primary aim of this study was to assess SP expression (mRNA and protein) in the left and right lungs of fetal sheep with and without a diaphragmatic hernia (DH). Left-sided DH was created in four fetal sheep at 65 days of gestational age (g.a.). Sham-operated animals were used as controls. At 138 days g.a., lungs were harvested and the following parameters were measured: SP-A, -B, and -C mRNA expression (Northern blot), SP-A and -B expression (Western blot), and AE2 cell density (immunohistochemistry). The lung weight-to-body weight ratio was reduced by 42% in DH animals. The left-to-right lung weight ratio was lower in DH animals (0.47 +/- 0.03 vs. 0.69 +/- 0.03), indicative of asymmetric lung growth. SP-A, -B, and -C mRNA expression were increased by 61.7%, 32.9%, and 75.5%, respectively, in the left lungs of DH animals. SP-A and SP-B were also increased in DH. In the right lung, SP expression (mRNA and protein) was not different between groups. AE2 cell density was higher (by 67%) in the left but not right lungs of DH animals. Although DH in fetal sheep results in significant lung hypoplasia, SP expression is not reduced. On the contrary, SP expression was increased in the ipsilateral lung of fetuses with left-sided DH. Furthermore, AE2 cell density is increased in DH, suggesting that the increase in SP mRNA and protein levels is due to increases AE2 cell number. Our data further support the premise that fetal lung hypoplasia favors an AE2 phenotype.

The influence of cortical maturation on the BOLD response: an fMRI study of visual cortex in children.

We performed blood oxygenation level-dependent (BOLD) functional MR imaging in 11 children younger than 5 y of age and 10 children older than 5 y of age. All but five of the children in the older age group were tested under light anesthesia. We examined the cerebral oxidative metabolism (CMRO(2)) associated with the processing of a flashed and a reversing checkerboard stimulus. These stimuli had been shown in a previous study to induce identical vascular responses. The reversing checkerboard activated twice the neuronal population of the flashed checkerboard, doubling the CMRO(2) associated with it. We compared the extent of activation for the positive BOLD response and found that it did not differ between the different age groups. We estimated the oxidative metabolism by examining the change in the local deoxyhemoglobin (HbR) concentration using Delta R2*. Because both stimuli induced the same vascular response, any increase in oxygen requirement would have to be met by the identical blood volume. Increasing CMRO(2) will therefore result in an increase in the oxygen extraction fraction (OEF), which raises the local HbR concentration. In the younger children, both checkerboard stimuli produced identical, high HbR concentrations. In the older children, the HbR concentration to the flashed stimulus was significantly lower than to the reversing stimulus. We conclude that, for identical stimuli, the oxidative energy requirement associated with the cortical processing is higher in young children than in older children because the presence of superfluous synaptic connections in the immature visual system activates a larger neuronal population.

Prenatally diagnosed giant omphaloceles: short- and long-term outcomes.

OBJECTIVES: To review prenatal findings, short- and long-term outcomes of giant omphaloceles (GO) managed at a single institution (1996-2001). METHODS: Prenatal findings and early postnatal outcomes were retrospectively reviewed. Clinical short- and long-term outcomes were analyzed in eight and five children respectively. Parents and physicians of the children were surveyed by written questionnaires about the children's subsequent health issues. (IRB 2002-2-2683). RESULTS: Seventeen pregnancies with GO were identified: Eight fetuses were live born, four ended in (terminations), two died in utero and three were lost to follow-up. Live-born fetuses had prenatal ascites, extreme levocardia and were delivered by cesarean section at a mean of 37 weeks' gestation with a mean birth weight of 2903 g. All neonates required intubation. Two infants (2/8) died within one year. Four of the six survivors had respiratory insufficiency with a mean ventilation time of 76 days. Respiratory and feeding problems complicated the early neonatal course. Long-term follow-up was available for five patients (mean age of 33.2 months). Asthma, recurrent pulmonary infections, feeding problems, gastroesophageal reflux and failure to thrive were the major problems. CONCLUSIONS: Respiratory and feeding problems were the most common neonatal and long-term medical management issues. Parents need to be counseled prenatally about the probability of multiple surgeries and long hospitalization following birth.

What effect does measuring children under anesthesia have on the blood oxygenation level-dependent signal? A functional magnetic resonance imaging study of visual cortex.

We performed functional magnetic resonance measurements involving visual stimuli on 10 children. Half of the children were measured awake, the other half were measured under light Sevoflurane anesthesia corresponding to 0.5 mean alveolar concentration. Each child was presented with a flashed and a reversing checkerboard, which previous investigations have shown to induce identical increases in cerebral blood flow. The latter stimulus activated double the number of neurons as the former so that cerebral metabolic rate of oxygen consumption (CMRO(2)) was doubled, leading to an effective rise of the oxygen extraction fraction. We measured the extent of activation by counting the number of activated pixels and assessed the change in CMRO(2) by measuring the change in the local deoxyhemoglobin (HbR) concentration, using change in spin relaxivity. In both groups of children, the extent of activation was larger for the flashed than the reversing checkerboard, although the absolute number of activated voxels was smaller for the children who were measured under anesthesia. The HbR concentration was significantly higher during the presentation of the reversing compared with the flashed checkerboard. The relative change in the HbR concentration to the flashed and reversing checkerboard was the same in the children who were measured under anesthesia as in the children who were measured awake. We conclude that light levels of anesthesia may reduce the extent of activation but does not unduly influence either CMRO(2) or cerebral blood flow, thus preserving the blood oxygenation level-dependent signal amplitude.

Anesthesia for fetal surgery.

Fetal surgery is a rapidly growing and evolving area. Fetal surgery is based on years of animal and clinical research. In contrast, anesthesia techniques for fetal surgery are based on clinical experience. The techniques that have emerged are safe for mother and fetus. In this review, the authors describe current techniques for anesthetic management of fetal surgery patients. General anesthesia is the primary technique used for hysterotomy based surgical correction of midgestation fetuses and ex utero interpartum corrections of end-gestation fetuses. Epidural analgesia, with general anesthesia as back-up, is the primary technique used for fetoscopic cases in which anesthetic care is required. Because of the myriad of anesthetic and surgical issues these cases generate, it is essential to have good communication and cooperation between surgeons and anesthesiologists from the preoperative period to the postoperative period. This will allow development of a cohesive anesthetic and surgical plan that can be used for the safe perioperative management of the fetal surgery patient.

Temporary tracheal occlusion in fetal sheep with lung hypoplasia does not improve postnatal lung function.

Prolonged fetal tracheal occlusion (TO) accelerates lung growth but leads to loss of alveolar epithelial type II (AE2) cells. In contrast, temporary TO leads to recovery of AE2 cells and their ability to produce surfactant. The aim of this study was to determine the effects of temporary TO in fetal sheep with lung hypoplasia on postnatal lung function, structure, and surfactant protein mRNA expression. Diaphragmatic hernia (DH) was created in 22 fetal sheep at 65 days of gestation. TO was performed between 110 days of gestation and full term (DH/TO, n = 7) and between 110 and 130 days of gestation (DH/TO+R, n = 6). Sham-operated fetuses (n = 11) served as controls. Lambs were delivered at approximately 139 days of gestation, and blood gas tensions were monitored over a 2-h resuscitation period. Temporary TO increased growth of the hypoplastic lung and restored surfactant protein mRNA expression and AE2 cell density but did not improve respiratory function above that of animals that underwent prolonged TO; DH/TO and DH/TO+R lambs were hypoxic and hypercapnic compared with Sham animals. Lung compliance remained low in DH/TO+R lambs, most likely as a consequence of the persistent increase in alveolar wall thickness in these animals.