Diagnostic pathway of the biopsy-naïve patient suspected for prostate cancer: Real-life scenario when multiparametric Magnetic Resonance Imaging is not centralized.

INTRODUCTION: We aimed to compare the pathway including multi-parametric Magnetic Resonance Imaging (mpMRI) versus the one without mpMRI in detection of prostate cancer (PCa) when mpMRI is not centralized. MATERIALS: January 2019-March 2020: prospective data collection of trans-perineal prostate biopsies. Group A: biopsy-naïve patients who underwent mpMRI (at any institution) versus Group B: patients who did not. Within Group A, patients were stratified into those with negative mpMRI (mpMRI-, PIRADS v2.1=1-3, with PSA density <0.15 if PIRADS 3) who underwent standard biopsy (SB), versus those with positive mpMRI (mpMRI+, when PIRADS 3-5, with PSA density>0.15 if PIRADS 3) who underwent cognitive fusion biopsy. RESULTS: Two hundred and eighty one biopsies were analyzed. 153 patients underwent mpMRI (Group A). 98 mpMRI+ underwent fusion biopsy; 55 mpMRI- underwent SB. 128 Group B patients underwent SB. Overall PCa detection rate was 52.3% vs. 48.4% (Group A vs. B, P=0.5). Non-clinically-significant PCa was detected in 7.8 vs. 13.3% (Group A vs. B, P=0.1). Among the 98 mpMRI+ Group A patients only 2 had non clinically-significant disease. In 55 mpMRI- patients who underwent SB, 10 (18.2%) had clinically-significant PCa. Prostate volume predicted detection of PCa. In Group B, age and PSA predicted PCa. Sensitivity of mpMRI was 75.0% for all PCa, 85.3% for clinically-significant PCa. CONCLUSION: Higher detection of PCa and lower detection of non-clinically-significant PCa favored mpMRI pathway. A consistent number of clinically-significant PCa was diagnosed after a mpMRI-. Thus, in real-life scenario, mpMRI- does not obviate indication to biopsy when mpMRI is not centralized. LEVEL OF EVIDENCE: 3.

The prognostic value of the neutrophil-to-lymphocyte ratio in patients with testicular cancer.

OBJECTIVES: To evaluate the potential prognostic value of the neutrophil-to-lymphocyte ratio (NLR) in testicular cancer. MATERIALS AND METHODS: 80 patients with testicular cancer treated at our institution from 2005 to 2018 were retrospectively reviewed. Age, tumor markers, stage and histotype at final pathology, eventual medical treatment, tumor recurrence and follow-up data were extracted. The NLR was retrospectively calculated from blood tests. Data were analyzed by medians comparison, linear correlation, univariate and multivariate Cox regression and survival curve analysis. RESULTS: Population's median age was 33 years and median follow-up was 40.5 months. Overall, the median NLR was significantly reduced after orchiectomy (2.2 [1.55-3.09] vs. 1.77 [1.34-2.46], M-W P<0.001). Post-orchiectomy NLR was higher in patients who had disease recurrence (2.51;IQ 1.84-3.74 vs 1.59; IQ 1.10-2.24; M-W P=0.001), regardless of disease's stage: HR=1,85 (95%CI 0,99-3,46) and HR=1,91 (95%CI 0,96-3,78) for stage disease I or stage II, respectively. After stratification of patients by post-orchiectomy NLR (optimal cut-off: 2.255), patients with lower NLR had significantly longer recurrence-free survival (107.7 months [95%CI 97,7-119,2] vs. 57.65 months [95%CI 48,2-81,1], P<0.001). Univariable and multivariable Cox proportional hazard analyses, showed post-orchiectomy NLR, histotype at final pathology and disseminated disease at diagnosis as predictors of recurrence. CONCLUSION: NLR is a simple and wildly available biomarker. Higher post-orchiectomy NLR was found independently correlated to higher risk of recurrence, regardless of disease stage, which could potentially lead to a worse prognosis.

The role of preoperative prostatic shape in the recovery of urinary continence after robotic radical prostatectomy: a single cohort analysis.

BACKGROUND: To explore the role of preoperative MRI prostate shape in urinary incontinence after robot-assisted radical prostatectomy (RARP). METHODS: Patients were stratified into four groups based on the mpMRI prostatic apex shape: Group A (prostatic apex overlapping the membranous urethra anteriorly and posteriorly), Group B and C (overlap of the prostatic apex of the anterior or posterior membranous urethra, respectively) and Group D (no overlap). Preoperative variables and intraoperative data were compared. Continence recovery was defined as no pad/day or 1 safety pad/day by an outpatient evaluation performed at 1, 3, 6, and 12 months after RARP. RESULTS: One hundred patients underwent RARP were classified as belonging to Group A (n = 30), Group B (n = 16), Group C (n = 14), and Group D (n = 40). Group D showed a significantly more favorable urinary continence recovery after RARP respect to all the other shapes presenting any forms of overlapping (HR = 1.9, 95% CI 1.2-3.1, p = 0.007). The estimated HR remained substantially unchanged after adjusting by age, body mass index, CCI, prostate volume, and bladder neck sparing (HR = 1.9, 95% CI 1.1-3.2, p = 0.016). The continence recovery median time was 9 months for Group A + B + C (95% CI 5-11) and 4 months for Group D (95% CI 2-6) (p = 0.023). CONCLUSION: Shape D showed a better continence recovery when compared to other shapes presenting any kind of overlapping of the prostatic apex over the membranous urethra.

How to manage renal masses in kidney transplant recipients? A collaborative review by the EAU-YAU kidney transplantation and renal cancer working groups.

INTRODUCTION: Kidney transplant (KT) recipients have a four-times higher risk of renal malignancies compared to general population. As these patients frequently harbor bilateral or multifocal tumors, the management of renal masses is still under debate. OBJECTIVE: To explore the current management of the native kidney masses in KT patients. ACQUISITION OF EVIDENCE: We performed a literature search on MEDLINE/PubMed database. A number of 34 studies were included in the present review. SYNTHESIS OF EVIDENCE: In frail patients with renal masses below 3 cm, active surveillance is a feasible alternative. Nephron-sparing surgery is not justified for masses in the native kidney. Radical nephrectomy is the standard treatment for post-transplant renal tumors of the native kidneys in KT recipients, with laparoscopic techniques leading to significantly less perioperative complication rates as compared to the open approach. Concurrent bilateral native nephrectomy at the time of transplantation can be considered in patients with renal mass and polycystic kidney disease, especially if no residual urinary output is present. Patients with localized disease and successful radical nephrectomy do not require immunosuppression adjustment. In metastatic cases, mTOR agents can ensure efficient antitumoral response, while maintaining proper immunosuppression in order to protect the graft. CONCLUSIONS: Post-transplant renal cancer of the native kidneys is a frequent occurrence. Radical nephrectomy is most frequently performed for localized renal masses. A standardized and widely-approved screening strategy for malignancies of native renal units is yet to be implemented.

Off-clamp laparoscopic partial nephrectomy in a hybrid room after tumor embolization versus conventional partial nephrectomy: A propensity score matched pair analysis.

OBJECTIVE: Off-clamp laparoscopic partial nephrectomy in a hybrid operating room after superselective arterial embolization (hLPN) is a promising minimally invasive approach. In this study, we compared the perioperative surgical outcomes of this innovative technique with the conventional standard of care laparoscopic partial nephrectomy (cLPN) technique. PATIENTS AND METHODS: Overall, 86 and 127 patients treated with hLPN and cLPN, respectively, were included. These two techniques were compared in terms of surgical complications, estimated blood loss (EBL), operative time, length of stay (LOS), surgical margins, and Trifecta achievement rate (defined as warm ischemia duration <25 min, negative surgical margins and absence of complications). A propensity score based on age, gender, BMI, preoperative eGFR and tumor size was used for a 1:1 matching of patients of each group. After matching, 2 groups of 67 patients with similar characteristics were obtained. RESULTS: Conversion rate to open surgery, complications and EBL were similar in both groups. Conversely, operative time, LOS and Trifecta rates favored hLPN. The multivariate analysis showed that hLPN had a 70% higher chance of Trifecta achievement than cLPN in all age groups and for all tumor size across the study population. CONCLUSION: Compared to a conventional approach, off-clamp laparoscopic partial nephrectomy in a hybrid room after superselective arterial embolization showed satisfying immediate surgical outcomes and reached a higher rate of Trifecta achievement. Mid and long-term functional and oncological results are needed to establish this minimally invasive surgical alternative.

Minimizing minimally invasive surgery: Current status of the single-port robotic surgery in Urology.

BACKGROUND: The novel da Vinci Single-Port (SP) robotic platform received the US FDA approval in 2018. The device, specifically conceived for single-site approach, is pushing through the limits of minimally invasive surgery. We sought to provide a comprehensive overview of the current status of the clinical experiences accomplished by the da Vinci SP in urology, and to discuss future perspectives. METHODS: A non-systematic literature review was performed focusing on single port articles in urological surgery using Medline/PubMed and Embase search electronic engines. The authors analyzed findings and a brief report of the clinical experience for surgical procedures completed by the SP platform was described. RESULTS: The current data available from single-port robotic established the safety and feasibility of urologic procedures using this novel platform. However, the results come from single-center case series, small cohorts and retrospective studies that need to be cautiously interpreted. Additional evidence is required to determine the asset of the SP platform in the urological community. CONCLUSIONS: The SP robotic system opens new frontiers on the surgical scenery facilitating the completion of urological surgeries through a single incision. Further comparative studies will be required to assess perioperative and long-term oncological and functional outcomes among SP, multi-arm robotic and open approaches.

PI-RADS score v.2 in predicting malignancy in patients undergoing 5α-reductase inhibitor therapy.

BACKGROUND: To investigate if the PI-RADS score represents an effective tool in detecting prostate cancer in patients treated with a 5α-reductase inhibitor (dutasteride) and to identify dedicated total serum PSA and PSA density thresholds. METHODS: Between April 2015 and March 2018, 75 patients under dutasteride treatment underwent multi-parametric magnetic resonance imaging (mpMRI) scans and US/MRI fusion prostate biopsy. Lesions were classified into two groups: Group 1 included PI-RADS 4 and 5 lesions, whilst Group 2 included PI-RADS 3-4-5 lesions. Lesions in groups 1 and 2 were further divided according to the patients' history of previous prostate biopsy. RESULTS: Ninety-seven lesions were detected. In PI-RADS 4-5 group, mpMRI showed a sensitivity of 78.0% and a specificity of 78.7%. The positive predictive value (PPV) was 79.6% and the negative predictive value (NPV) 77.1%. In PI-RADS 3-4-5 group, sensitivity was 100%, specificity 21.3%, PPV 57.5%, NPV 100%. In PI-RADS 4-5 biopsy-naive group sensitivity was 71.4%, specificity 75.0%. PPV 78.9% and NPV 66.7%. In PI-RADS 4-5 non-biopsy-naive group sensitivity was 82.8%, specificity 80.6%, PPV 80%, and NPV 83.3%. PI-RADS 3-4-5 biopsy-naive group showed sensitivity 100%, specificity 31.3%, PPV 65.6%, NPV 100%. PI-RADS 3-4-5 non-biopsy-naive group showed sensitivity 100%, specificity 16.1%, PPV 52.7%, and NPV 100%. ROC curve analysis indicated a serum total PSA threshold of 6 ng/ml (AUC: 0.71-95% confidence interval: 0.60-0.81) and a PSA density >0.22 (AUC: 0.70-95% confidence interval: 0.6-0.81) as optimal cut-offs for recommending prostate biopsy. CONCLUSIONS: In our experience the PI-RADS score proved to be sufficiently accurate in predicting prostate cancer in patients under dutasteride therapy.

Is thulium laser vapoenucleation of the prostate equally safe and effective in elderly patients? A propensity score matched analysis of early perioperative and functional outcomes. / Vapoenucleación prostática con láser Tulio. ¿Es igual de segura y efectiva en pacientes ancianos? Análisis por puntuación de propensión de los resultados funcionales y perioperatorios tempranos.

PURPOSE: To evaluate if thulium laser vapoenucleation of the prostate (ThuVEP) is equally safe and effective in a selected cohort of elderly patients when compared to "younger" patients. MATERIALS AND METHODS: We performed a retrospective analysis of consecutive patients who underwent ThuVEP between September 2018 and February 2020. After application of the inclusion/exclusion criteria, patients were stratified according to the 75 years-old cut-off point suggested by the WHO. Group A included patients < 75 years-old; Group B included patients > 75 years-old. Preoperative assessment included urological consultation, prostate specific antigen (PSA), International Prostate Symptom Score (IPSS) and quality of life index, transrectal ultrasound to estimate prostate volume (PVol), and uroflowmetry to assess preoperative Qmax, Qave and post-void residual volume (PVR). Perioperative and postoperative data were analyzed during 3-month follow-up. RESULTS: After propensity-score analysis, 51 versus 51 patients were 1:1 matched according to PVol, PSA, Qmax, IPSS and QoL. Patients were comparable at baseline excluding age (65 (IQR 59-70) versus 79 (IQR 77-82) years, Group A versus B, respectively, p-value < 0.001). No differences were found in terms of hemoglobin drop, complications rate, catheterization time and length of hospital stay. Group A (younger) patients had more significant improvement in 30-days absolute Qmax, Qave and ΔQmax. At 90-days follow-up, the differences between the groups disappeared. Within the 90-days follow-up, no significant differences were found in the readmission rate, with no need of reinterventions. CONCLUSIONS: In our hands, even in elderly patients affected by BPH, ThuVEP appears to be a safe and effective treatment option.

The relationship between inguinal hernia and minimally-invasive surgery for prostate cancer: A systematic review of the literature. / La relación entre hernia inguinal y cirugía mínimamente invasiva para el cáncer de próstata: revisión sistemática de la literatura.

OBJECTIVE: We aimed to perform a systematic review about the relationship between inguinal hernia and surgery for prostate cancer. BACKGROUND: Diagnosis of abdominal wall defects and prostate cancer may be either synchronous or metachronous. The convenience and safety of combined prostatectomy and hernioplasty, the incidence of hernias after prostatectomy and the feasibility of prostatectomy in patients with previous laparoscopic hernioplasty are still debated. METHODS: PubMed and Embase were queried by dedicated search strings. Two researchers independently reviewed the pooled references and selected the articles of interest, including reviews. RESULTS: Sixty-five studies were evaluated, 22 of them analysed the feasibility and the outcomes of a combined surgery, namely one-stage radical prostatectomy and herniorrhaphy or hernioplasty. Literature evidences support the combined intervention to patients suffering from an inguinal hernia and a prostate cancer amenable of radical prostatectomy. Sixteen studies addressing the potential increase in the occurrence of inguinal hernia after radical prostatectomy were evaluated. Approximately 15% of patients who undergo retro-pubic radical prostatectomy will develop inguinal hernia. It is suggested that the incidence might be lower in laparoscopic prostatectomy series, particularly in case of transperitoneal approach. The median time to the appearance of the hernia is around 6 months. After evaluation of 14 studies, it is concluded that laparoscopic hernioplasty does not preclude prostatectomy but hinders further pelvic surgery. CONCLUSIONS: One-stage combined hernioplasty and radical prostatectomy may be accepted except in cases of lymph-nodes dissection and/or positive hydro-distress test of the urethro-vesical anastomosis. Accurate patient's counselling and dedicated consent form are mandatory, in the setting of an experienced multidisciplinary team.

Undetectable PSA after radical prostatectomy is more likely in low burden N+ prostate cancer patients when an extended lymph node dissection is performed. / Frecuencia de PSA indetectable en pacientes con cáncer de próstata N+ baja carga tras prostatectomía radical y linfadenectomía ampliada.

OBJECTIVES: To analyze the likelihood of undetectable PSA (< 0.01 ng/mL) after extended (ePLND) versus standard pelvic lymph-nodes dissection (sPLND) in pN+ patients. MATERIALS AND METHODS: The institutional prospectively maintained Prostate Cancer Database was queried for patients who underwent radical prostatectomy with PLND and were found with 3or less lymph-nodal metastases between 2007 and 2017. The extension of the PLND was defined according to the number of lymph-nodes (LN) removed. Patients in the 75th or higher percentile of lymph-nodes removed were considered as the ePLND group; patients in the 25th or lower percentile in the sPLND group. Groups were compared in clinical and pathological variables. Student T-test was used for comparing continuous variables; chi-square test was used for categorical variables. Multivariable logistic regression assessed the probability of undetectable PSA at 3rd month postoperatively. Kaplan-Meier method estimated the probability of biochemical recurrence. Differences between the groups were compared by Log-rank test. RESULTS: 1478 patients were treated within the time span considered. 95 with 1 to 3 lymph-nodal metastases were extracted. After accounting for inclusion criteria, 23 patients with a median of 11 LN removed were included in the sPLND group (25th percentile); 23 patients with > 27 LN were included in ePLND group (75th percentile). Surgical time was longer for ePLND. Sixteen patients (69.6%) who underwent ePLND had undetectable PSA postoperatively. At multivariable analysis, the probability of undetectable PSA at 3rd month was higher in patients who received an ePLND (HR=5.18; IC 95%=1.16-23.11; P=.03). CONCLUSIONS: ePLND is more likely to predict undetectable PSA at third month after radical prostatectomy, irrespective of disease characteristics.

The impact of T1 renal tumor characteristics on baseline renal function in patients undergoing partial nephrectomy: A renal scan based objective assessment.

INTRODUCTION AND OBJECTIVES: To objectively assess the impact of renal tumors characteristics and other measurable factors on baseline renal function in patient undergoing partial nephrectomy (PN). METHODS: Patients who underwent laparoscopic PN for a T1 renal mass between 2012 and 2016 and who also had a mercapto-acetyltriglycine renal scan prior to surgery were retrieved from a single institution prospectively-collected database. Split renal function (SRF) and Effective Renal Plasma Flow (ERPF) for both the operated kidney and the unaffected contralateral were calculated. Patient demographics and tumor characteristics (e.g. size, location and; nephrometry score) were assessed. Renal function of both the operated and the unaffected; contralateral kidney were compared. Statistical analysis was performed by using Statistica 8.0 (StatSoft). RESULTS: 227 patients were deemed eligible and included in the analysis. Univariable analysis showed a significant impact of age-adjusted CCI (p = 0.027), hypertension (p = 0.031) and age (p < 0.001) on operated kidney ERPF. Gender (p = 0.011), hypertension (p = 0.042), CCI (both standard and age-adjusted, p = 0.021 and = 0.003, respectively) and age (p < 0.001) were significantly; associated with contralateral unaffected kidney ERPF. Multivariable analysis confirmed age (p < 0.001) and hypertension (p < 0.021) as independent factors in both the operated and the unaffected kidney. CONCLUSIONS: Characteristics of the renal mass (including nephrometry score and size) seem to have no clinically relevant impact on baseline renal function in patients undergoing partial nephrectomy for cT1 renal tumors. Age, hypertension and co-morbidities confirm to represent un-modifiable significant factors influencing baseline renal function.

Predictive factors of overall and major postoperative complications after partial nephrectomy: Results from a multicenter prospective study (The RECORd 1 project).

INTRODUCTION AND OBJECTIVES: To analyze postoperative complications and to assess for significant predictive factors during partial nephrectomy (PN) using a large multicenter dataset. METHODS: Patients who underwent PN for clinical T1 renal tumors at 19 urological Italian centers (Registry of Conservative Renal Surgery [RECORd] project) were evaluated between 2009 and 2012. Anthropometric data, comorbidities and perioperative outcomes were analyzed. Complications were divided as intra- and postoperative, medical and surgical, as appropriate. The severity of postoperative complications was graded according to the modified Clavien classification system. Patients who experienced intraoperative complications were excluded from the analyses for the potential confounding effect in the evaluation of predicting factors for postoperative complications. RESULTS: Overall, 979 patients were analyzed: open, laparoscopic and robot-assisted (available since 2011) surgical approaches were used in 522 (56.4%), 286 (30.9%) and 117 (12.6%) cases, respectively. Surgical postoperative complications were reported in 121 (13.1%) cases (32 (3.5%) were Clavien 3), medical were reported in 52 (5.6%) cases (3 (0.3%) were Clavien 3). No Clavien 4 complications were reported. At multivariable analysis, ECOG score ≥1 (OR 1.98; p = 0.002), lower preoperative hemoglobin (OR 0.71; p < 0.0001) and open surgical approach (2.91; p = 0.02) were significant predictive factors of overall surgical postoperative complications, ECOG score ≥1 (OR 1.93; p = 0.04) and surgical approach (p = 0.05) were significant predictive factors of Clavien 3 either surgical or medical postoperative complications. CONCLUSIONS: Comorbidities and surgical approach should be considered in preoperative evaluation of patients undergoing PN, as they resulted to play a significant role in the occurrence of postoperative complications.

Groundwater contamination in coastal urban areas: Anthropogenic pressure and natural attenuation processes. Example of Recife (PE State, NE Brazil).

In a context of increasing land use pressure (over-exploitation, surface-water contamination) and repeated droughts, identifying the processes affecting groundwater quality in coastal megacities of the tropical and arid countries will condition their long-term social and environmental sustainability. The present study focuses on the Brazilian Recife Metropolitan Region (RMR), which is a highly urbanized area (3,743,854 inhabitants in 2010) on the Atlantic coast located next to an estuarial zone and overlying a multi-layered sedimentary system featured by a variable sediment texture and organic content. It investigates the contamination and redox status patterns conditioning potential attenuation within the shallow aquifers that constitute the interface between the city and the strategic deeper semi-confined aquifers. These latter are increasingly exploited, leading to high drawdown in potenciometric levels of 20-30m and up to 70m in some high well density places, and potentially connected to the surface through leakage. From a multi-tracer approach (major ions, major gases, δ(11)B, δ(18)O-SO4, δ(34)S-SO4) carried out during two field campaigns in September 2012 and March 2013 (sampling of 19 wells and 3 surface waters), it has been possible to assess the contamination sources and the redox processes. The increasing trend for mineralization from inland to coastal and estuarial wells (from 119 to around 10,000µS/cm) is at first attributed to water-rock interactions combined with natural and human-induced potentiometric gradients. Secondly, along with this trend, one finds an environmental pressure gradient related to sewage and/or surface-channel network impacts (typically depleted δ(11)B within the range of 10-15‰) that are purveyors of chloride, nitrate, ammonium and sulfate. Nitrate, ammonium and sulfate (ranging from 0 to 1.70mmol/L, from 0 to 0,65mmol/L, from 0.03 to 3.91mmol/L respectively are also potentially produced or consumed through various redox processes (pyrite oxidation, denitrification, dissimilatory nitrate reduction to ammonium) within the system, as is apparent within a patchwork of biogeochemical reactors. Furthermore, intensive pumping in the coastal area with its high well density punctually leads to temporary well salinization ([Cl] reaching temporarily 79mmol/L). Our results, summarized as a conceptual scheme based on environmental conditions, is a suitable basis for implementing sustainable management in coastal sedimentary hydrosystems influenced by highly urbanized conditions.

A snapshot of nephron-sparing surgery in Italy: a prospective, multicenter report on clinical and perioperative outcomes (the RECORd 1 project).

INTRODUCTION: Nephron-sparing surgery (NSS) has become the standard of care for the surgical management of small and clinically localized renal cell carcinoma (RCC). The conservative management of those RCCs is increasing over time. Aim of this study was to report a snapshot of the clinical, perioperative and oncological results after NSS for RCC in Italy. MATERIAL AND METHODS: We evaluated all patients who underwent conservative surgical treatment for renal tumours between January 2009 and December 2012 at 19 urological Italian Centers (RECORd project). Perioperative, radiological and histopathological data were recorded. Surgical eras (2009 vs 2012 and year periods 2009-2010 vs 2011-2012) were compared. RESULTS: Globally, 983 patients were evaluated. More recently, patients undergoing NSS were found to be significantly younger (p = 0.05) than those surgically treated in the first study period, with a significantly higher rate of NSS with relative and imperative indication (p < 0.001). More recently, a higher percentage of procedures for cT1b or cT2 renal tumours was observed (p = 0.02). Utilization rate of open partial nephrectomy (OPN) constantly decreased during years, laparoscopic partial nephrectomy (LPN) remained almost constant while robot-assisted partial nephrectomy (RAPN) increased. The rate of clampless NSS constantly increased over time. The use of at least one haemostatic agent has been significantly more adopted in the most recent surgical era (p < 0.001). CONCLUSIONS: The utilization rate of NSS in Italy is increasing, even in elective and more complex cases. RAPN has been progressively adopted, as well as the intraoperative utilization of haemostatic agents and the rate of clampless procedures.

A spectroscopic NMR investigation of the calcium silicate hydrates present in cement and concrete.

NMR spectroscopy is applied to study microstructure of calcium silicate hydrates present in cement and concrete. It is shown that 29Si NMR gives information on the siliceous skeleton of the hydrates. 1H NMR, using CRAMPS techniques, allows to discriminate between protons linked to silicon atoms or to calcium atoms. A first investigation of reference compounds indicates that 43Ca NMR will be powerful to determine calcium atom sites in the structure.

A comparison of parenteral and enteral feeding in neonatal piglets, including an assessment of the utilization of a glutamine-rich, pediatric elemental diet.

BACKGROUND: The amino acid requirement profile for infants is different than that for adults and needs to be established; this profile also is different for infants receiving total parenteral nutrition. We used the neonatal piglet as a model for the infant to address (1) the metabolic and physiologic changes due to route of feeding and (2) the adequacy of the amino acid pattern in a pediatric elemental diet. METHODS: Diets differed only in their amino acid pattern (modified human milk [MHM] and a commercial pediatric elemental diet [PED]) and were fed continuously for 8 days. Control piglets were fed MHM diet via gastric catheters (IG) and were compared with pigs fed MHM diet via venous catheters (IV) or to pigs IG-fed PED. RESULTS: MHM-IV piglets experienced enlarged livers and gut atrophy, and lower nitrogen retention and body protein content. Higher glutamine (and lower glutamate) in PED-IG, compared with MHM-IG, produced no apparent advantage with respect to gut growth or histology. Proline, histidine, and lysine may have been limiting, and isoleucine and valine excessive, in the PED-IG diet as indicated by plasma concentrations, compared with sow-fed piglets; however, imbalances in the amino acid profile were not excessive because nitrogen retention was not different between MHM-IG or PED-IG pigs. CONCLUSIONS: Therefore, the amino acid profile of MHM needs to be modified to improve nitrogen retention during parenteral feeding and the profile of oral PED could be improved to normalize plasma amino acid concentrations.

Development of the indicator amino acid oxidation technique in chickens: L-[1-(14)C]phenylalanine infusion dose and phenylalanine oxidation.

Amino acid requirements of broiler breeder chickens are not well known. The indicator amino acid oxidation (IAAO) technique was adapted for use in broiler breeders as a rapid and sensitive method to determine amino acid requirements. During IAAO, phenylalanine oxidation decreases, inversely to the changes in protein synthesis, as the intake of the limiting test amino acid increases from deficient to adequate. Above the adequate level, phenylalanine oxidation remains constant. Before IAAO can be employed, the optimum priming and constant infusion doses of phenylalanine must be determined. Prelaying catheterized birds aged 20 to 24 wk were placed in closed oxidation chambers attached to a breath collection apparatus. A constant L-[1-(14)C]phenylalanine dose of 3.5 microCi/kg BW/h and priming doses of 4.5, 5.5, and 7.0 microCi/kg BW were used to determine optimal prime:constant dose ratios, minimum time taken for breath 14CO2 excretion to become constant (plateau), and adequate percentage of phenylalanine oxidized. At this constant infusion rate, the optimal priming dose of L-[1-(14)C]phenylalanine was 5.5 microCi/kg BW, resulting in a prime:constant dose ratio of 1.6:1. By using this ratio, the average time taken for breath 14CO2 to reach plateau was 60 min. Average phenylalanine oxidation at plateau, corrected for bicarbonate retention, was 5.5 +/- 1.4% (mean +/- SD), which is adequate for IAAO studies using deficient-to-excess levels of test amino acids. To the authors' knowledge, this study is the first in chickens to establish a primed, constant infusion technique using L-[1-(14)C]phenylalanine. The IAAO technique will be used in future studies to determine amino acid requirements in chickens.

Development of the indicator amino acid oxidation technique in chickens: calibration of oxidation system and determination of bicarbonate retention factor.

The indicator amino acid oxidation technique has been widely used as a rapid and sensitive method to determine amino acid requirement. In this technique, the indicator 14C-amino acid is continuously infused and breath 14CO2 is collected to determine oxidation rate, which is used to predict requirement. However, a portion of the 14CO2 produced from amino acid oxidation is retained in the body and must be determined to correct oxidation rates based on breath 14CO2 collection. To develop the indicator amino acid oxidation technique for use in poultry, it is important to accurately measure expired and retained CO2; these measurements were accomplished using intravenous infusion of NaH14CO3. Oxidation chambers were constructed and calibrated to ensure complete collection of breath 14CO2. Hydrochloric acid was infused over 1 h into a beaker containing NaH14CO3 in four closed oxidation chambers, and the 14CO2 released was collected over 2 h. Of the initial radioactivity dose, 99.3 +/- 1.9% was recovered in collected 14CO2. We concluded that the oxidation chamber apparatus is adequate for complete recovery of expired 14CO2. In Experiment 2, we determined bicarbonate retention in five broiler breeder roosters from a primed, constant infusion of NaH14CO3 into the jugular vein for 4 h. At steady state, 86.0 +/- 1.4% of NaH14CO3 infusion was recovered in breath. Because 14% of infused 14C is retained within the body, the present results demonstrate the need to determine bicarbonate retention in chickens during oxidation studies and use it as a correction factor in subsequent experiments.

Effect of common antinutritive factors and fibrous feedstuffs in pig diets on amino acid digestibilities with special emphasis on threonine.

Most feedstuffs contain antinutritive factors (ANF) such as insoluble fibers, lignins, tannins, and lectins. Intake of these ANF has the ability to reduce nutrient digestibility and to increase endogenous protein losses, such as through increased intestinal mucus secretion. The objective of this experiment was to determine the apparent ileal digestibilities (AID) of AA of 6 ANF-enriched diets to estimate endogenous protein loss associated with these ingredients in diets for young pigs. Forty-two 10-kg BW pigs fitted with a simple T-cannula at the distal ileum were randomly assigned to 1 of 7 casein-based diets with: no supplement (control), 100 g/kg of canola meal (CM), 100 g/kg of wheat bran (WB), 150 g/kg of barley (BR), 22.5 g/kg of lignin (LG), 15 g/kg of kidney beans [as a lectin (LE) source], and 15 g/kg of tannins (TN). All diets were formulated to be similar in N, indispensable AA, and caloric contents. After a 7-d adaptation to the test diets, N balance was conducted for 5 d, followed by 24 h of collection of digesta for analyses of AA. Pigs fed BR had 17% lower ADG and 15% lower feed conversion ratio (P < 0.05) compared with control and CM pigs. Pigs fed diets containing WB and BR had lower N retention as a percentage of absorbed N compared with all other groups (P = 0.03). The AID for CP was lower in BR, WB, and LE pigs compared with control. Of the AA, AID of Thr was notably lowest in BR, WB, and TN pigs (P < 0.05). The standardized ileal digestibility was lower in WB and BR pigs for most indispensable AA. Altogether, these data suggest that hemicellulose fiber, at concentrations typical in commercial swine diets, reduces AID of AA by increasing endogenous losses. Understanding the differential effects of ANF on endogenous losses of individual dietary AA will improve the accuracy of diet formulation.