A novel application of 1H magnetic resonance spectroscopy: non-invasive identification of spermatogenesis in men with non-obstructive azoospermia.

BACKGROUND: About 10% of infertile men have no sperm in their ejaculate due to poor or absent spermatogenesis, also known as non-obstructive azoospermia (NOA). Testis (1)H magnetic resonance spectroscopy ((1)H-MRS) is a non-invasive imaging tool that can potentially identify and localize spermatogenesis in the testis. This study sought to identify metabolic signatures associated with various histological states of spermatogenesis in infertile men. METHODS: Quantitative high resolution magic angle spinning spectroscopy was performed on snap frozen testicular tissue from 27 men with three classic histological patterns: (i) normal spermatogenesis (men with prior paternity undergoing vasectomy reversal), (ii) maturation arrest (early or late, MA) or (iii) Sertoli-cell only (SCO). Concentrations of 19 tissue metabolites were acquired from each biopsy specimen. One-way ANOVA analysis was used to determine inter-group differences in metabolite concentrations among the three histologic groups. RESULTS: Phosphocholine (PC) and taurine tissue concentrations were significantly different between normal and SCO tissue. Mean PC concentrations were three times higher in normal testes compared with SCO (5.4 +/- 1.4 versus 1.5 +/- 0.3 mmol/kg; P = 0.01). No differences in metabolite concentrations were observed between normal and MA testes or between SCO and MA testes. Further histologic stratification of MA testes into subsets of those with (early) and without (late) spermatids or mature sperm, identified differences in PC concentrations. A predictive model for sperm presence with (1)H-MRS was developed based upon PC tissue concentrations. CONCLUSIONS: PC concentrations are significantly higher in testes with spermatogenesis. This suggests that a unique metabolic signature for spermatogenesis is possible using (1)H-MRS which could aid in the non-invasive diagnosis of sperm in men with NOA.

Quantitative metabolic profiles of 2nd and 3rd trimester human amniotic fluid using (1)H HR-MAS spectroscopy.

OBJECT: To establish and compare normative metabolite concentrations in 2nd and 3rd trimester human amniotic fluid samples in an effort to reveal metabolic biomarkers of fetal health and development. MATERIALS AND METHODS: Twenty-one metabolite concentrations were compared between 2nd (15-27 weeks gestation, N = 23) and 3rd (29-39 weeks gestation, N = 27) trimester amniotic fluid samples using (1)H high resolution magic angle spinning (HR-MAS) spectroscopy. Data were acquired using the electronic reference to access in vivo concentrations method and quantified using a modified semi-parametric quantum estimation algorithm modified for high-resolution ex vivo data. RESULTS: Sixteen of 21 metabolite concentrations differed significantly between 2nd and 3rd trimester groups. Betaine (0.00846+/-0.00206 mmol/kg vs. 0.0133+/-0.0058 mmol/kg, P < 0.002) and creatinine (0.0124+/-0.0058 mmol/kg vs. 0.247+/-0.011 mmol/kg, P < 0.001) concentrations increased significantly, while glucose (5.96+/-1.66 mmol/kg vs. 2.41+/-1.69 mmol/kg, P < 0.001), citrate (0.740+/-0.217 mmol/kg vs. 0.399+/-0.137 mmol/kg, P < 0.001), pyruvate (0.0659+/-0.0103 mmol/kg vs. 0.0299+/-0.286 mmol/kg, P < 0.001), and numerous amino acid (e.g. alanine, glutamate, isoleucine, leucine, lysine, and valine) concentrations decreased significantly with advancing gestation. A stepwise multiple linear regression model applied to 50 samples showed that gestational age can be accurately predicted using combinations of alanine, glucose and creatinine concentrations. CONCLUSION: These results provide key normative data for 2nd and 3rd trimester amniotic fluid metabolite concentrations and provide the foundation for future development of magnetic resonance spectroscopy (MRS) biomarkers to evaluate fetal health and development.

Small catheter tube thoracostomy: effective in managing chest trauma in stable patients.

BACKGROUND: Image-guided small catheter tube thoracostomy (SCTT) is not currently used as a first-line procedure in the management of patients with chest trauma. We adopted a practice recommendation to use SCTT as a less invasive alternative in the treatment of chest injuries. We reviewed our trauma registry to evaluate our change in practice and the effectiveness of SCTT. METHODS: Retrospective review of all tube thoracostomies (TT) performed in patients with chest injury at a level I trauma center from September 2002 through March 2006. Data collected included age, sex, indications and timing for TT, use of antibiotics, length of stay, complications, and outcomes. Large catheter tube thoracostomy (LCTT) not performed in the operating room or trauma room and all SCTT were deemed nonemergent. RESULTS: There were 565 TT performed in 359 patients. Emergent TT was performed in 252 (70%) and nonemergent TT in 157 (44%) patients, of which 63 (40%) received LCTT and 107 (68%) received SCTT. Although SCTT was performed later after injury than nonemergent LCTT (5.5 days vs. 2.3 days, p < 0.001), average duration of SCTT was shorter (5.5 days vs. 7 days, p < 0.05). Rates of hemothoraces were similarly low for SCTT versus nonemergent LCTT (6.1% vs. 4.2%, p = NS) and rates of residual/recurrent pneumothoraces were not significantly different (8% vs. 14%, p = NS). The rate of occurrence of fibrothorax, however, was significantly lower for SCTT compared with nonemergent LCTT (0% vs. 4.2%, p < 0.05). In patients receiving a single nonemergent TT, SCTT was performed in 55 (61%) and LCTT in 35 (39%). A comparison of these groups revealed that SCTT was performed in older patients (p < 0.05), and was associated with a lower Injury Severity Score (p < 0.05) and shorter length of stay (p = 0.05). SCTT was increasingly used in younger and more seriously injured patients as our experience grew. CONCLUSION: SCTT is effective in managing chest trauma. It is comparable with LCTT in stable trauma patients. This study supports adopting image-guided small catheter techniques in the management of chest trauma in stable patients.