On the intersystem crossing rate in a Platinum(II) donor-bridge-acceptor triad.

The rates of ultrafast intersystem crossing in acceptor-bridge-donor molecules centered on Pt(II) acetylides are investigated. Specifically, a Pt(II) trans-acetylide triad NAP--Pt--Ph-CH2-PTZ [1], with acceptor 4-ethynyl-N-octyl-1,8-naphthalimide (NAP) and donor phenothiazine (PTZ), is examined in detail. We have previously shown that optical excitation in [1] leads to a manifold of singlet charge-transfer states, S*, which evolve via a triplet charge-transfer manifold into a triplet state 3NAP centered on the acceptor ligand and partly to a charge-separated state 3CSS (NAP--Pt-PTZ+). A complex cascade of electron transfer processes was observed, but intersystem crossing (ISC) rates were not explicitly resolved due to lack of spin selectivity of most ultrafast spectroscopies. Here we revisit the question of ISC with a combination and complementary analysis of (i) transient absorption, (ii) ultrafast broadband fluorescence upconversion, FLUP, which is only sensitive to emissive states, and (iii) femtosecond stimulated Raman spectroscopy, FSR. Raman resonance conditions allow us to observe S* and 3NAP exclusively by FSR, through vibrations which are pertinent only to these two states. This combination of methods enabled us to extract the intersystem crossing rates that were not previously accessible. Multiple timescales (1.6 ps to ∼20 ps) are associated with the rise of triplet species, which can now be assigned conclusively to multiple ISC pathways from a manifold of hot charge-transfer singlet states. The analysis is consistent with previous transient infrared spectroscopy data. A similar rate of ISC, up to 20 ps, is observed in the trans-acetylide NAP--Pt--Ph [2] which maintains two acetylide groups across the platinum center but lacks a donor unit, whilst removal of one acetylide group in mono-acetylide NAP--Pt-Cl [3] leads to >10-fold deceleration of the intersystem crossing process. Our work provides insight on the intersystem crossing dynamics of the organo-metallic complexes, and identifies a general method based on complementary ultrafast spectroscopies to disentangle complex spin, electronic and vibrational processes following photoexcitation.

Blunt traumatic diaphragmatic injuries in children.

Diaphragmatic injuries following blunt trauma are rare. From January 1988 to February 2002 eight children were treated at the Children's Hospital at Westmead for diaphragmatic injury. Male to female ration was 5:3. Motor vehicle crashes were the most common cause. The injury was left-sided in four, right sided in three and central in one. Initial plain radiograph and computerised tomography detected the injury in 50% of cases. Laparotomy, contrast study and autopsy identified the rupture in one each. Associated injuries were present in all cases. Seven children had laparotomy and repair of the diaphragmatic rupture. The commonest site of rupture was posterolateral (37.5%). Diagnosis was delayed in two cases. There were two deaths (25% mortality) in the series, both due to associated injuries. Although rare, diaphragmatic rupture must be considered in any child with thoracoabdominal injury. Diagnosis may be difficult and require extensive investigation. Mortality usually results from associated injuries.

Retained common-duct stones after open cholecystectomy and duct exploration in children.

A retrospective study was performed of 250 patients with cholelithiasis treated at the Royal Children's Hospital, (RCH) Melbourne, over 25 years by open operation; 32 (12.8%) had proven choledocholithiasis on either preoperative imaging, operative cholangiography (OpCG), or postoperative investigation. A further 3 had underlying congenital biliary abnormalities and were excluded from further study. Thirty-one of the 32 were explored at open operation, 27 after OpCG and 4 on clinical grounds. One retained common-bile-duct (CBD) stone was undetected until the postoperative period (1/250, 0.25%). Seven ducts were not cleared, giving a duct exploration failure rate of 22.6% (7/31). All 8 retained CBD stones were identified in the early postoperative period and managed with a variety of techniques, including endoscopic retrograde cholangio-pancreatography (ERCP). The incidence of retained stones after open CBD exploration was high (22.6%), and can be attributed to difficulties in operative technique dealing with the smaller paediatric CBD. In addition, haemolytic disease seems to induce a propensity for choledocholithiasis. Given the small numbers presenting with cholelithiasis to RCH (10 per year), it is suggested that a selective approach to CBD exploration is appropriate in children. With the increasing use of laparoscopic cholecystectomy in children and the inherent technical difficulties of laparoscopic operative cholangiography, ERCP may offer an alternative solution in dealing with CBD stones rather than open or laparoscopic CBD exploration.

Evaluation of nine automated high-sensitivity C-reactive protein methods: implications for clinical and epidemiological applications. Part 2.

BACKGROUND: C-Reactive protein (CRP) can provide prognostic information about risk of future coronary events in apparently healthy subjects. This application requires higher sensitivity assays than have traditionally been available in the clinical laboratory. METHODS: Nine high-sensitivity CRP (hs-CRP) methods from Dade Behring, Daiichi, Denka Seiken, Diagnostic Products Corporation, Iatron, Kamiya, Olympus, Roche, and Wako were evaluated for limit of detection, linearity, precision, prozone effect, and comparability with samples from 388 apparently healthy individuals. RESULTS: All methods had limits of detection that were lower than the manufacturers' claimed limit of quantification except for the Kamiya, Roche, and Wako methods. All methods were linear at 0.3-10 mg/L. The Diagnostic Products Corporation, Kamiya, Olympus, and Wako methods had imprecision (CVs) >10% at 0.15 mg/L. The Iatron, Olympus, and Wako methods demonstrated prozone effects at hs-CRP concentrations of 12, 206, and 117 mg/L, respectively. hs-CRP concentrations demarcating each quartile in a healthy population were method-dependent. Ninety-two to 95% of subjects were classified into the same quartile of hs-CRP established by the Dade Behring method by the Denka Seiken, Diagnostic Products Corporation, Iatron, and Wako methods. In contrast, 68-77% of subjects were classified into the same quartile by the Daiichi, Kamiya, Olympus, and Roche methods. No subject varied by more than one quartile by any method. CONCLUSIONS: Four of the nine examined hs-CRP methods classified apparently healthy subjects into quartiles of hs-CRP similar to the classifications assigned by the comparison method. Additional standardization efforts are required because an individual patient's results will be interpreted using population-based cutpoints.

Direct measurement of LDL-C in children: performance of two surfactant-based methods in a general pediatric population.

OBJECTIVES: Several pediatric advisory groups have recommended selective screening for dyslipidemia in children. Low-density lipoprotein cholesterol (LDL-C) is measured clinically with the Friedewald calculation in fasting samples. Nonfasting measurement of LDL-C would be clinically useful in children. DESIGN AND METHODS: In the present study, we examine the performance of two surfactant-based direct LDL-C assays in paired samples, fasting and nonfasting, from 100 children. RESULTS: LDL-C in the fasting state was significantly lower with the Friedewald estimation: 2.43 +/- 0. 61 mmol/L, N-geneous (Genzyme Corp.) direct LDL-C: 2.30 +/- 0.59 mmol/L, and Roche (Roche Diagnostics) direct LDL-C: 2.32 +/- 0.57 mmol/L than with ultracentrifugation-dextran-sulfate-Mg(2+) precipitation (UC-DS): 2.47 +/- 0.64 mmol/L. Moreover, there was increased negative bias using nonfasting samples with N-geneous: 2. 25 +/- 0.56 mmol/L and Roche: 2.26 +/- 0.56 mmol/L compared with fasting UC-DS. Correlation with US-DS was highest for Friedewald (r = 0.974) and fasting N-geneous (r = 0.973), and lowest with nonfasting N-geneous (r = 0.849) and Roche in fasting (r = 0.891) and nonfasting samples (r = 0.747). The sensitivity at LDL-C concentration of 2.85 mmol/L for the two direct methods when either fasting or nonfasting samples were used, was lower than that obtained with Friedewald. CONCLUSION: Overall, these direct LDL-C assays demonstrated limited utility in screening children but may be useful in the management of lipid disorders.

Prospective analysis of intraoperative frozen needle biopsy of solid renal masses in adults.

PURPOSE: We prospectively determined the accuracy of intraoperative needle biopsy of solid renal masses. MATERIALS AND METHODS: A total of 103 patients diagnosed with a solid renal mass and scheduled for surgery were prospectively evaluated. Radical or partial nephrectomy was performed, and biopsy of the surgical specimen was done twice through the tumor using an 18 gauge biopsy gun. Biopsy specimens of 106 tumors were sent for frozen sectioning, stained with hematoxylin and eosin, and reviewed by 2 independent pathologists blinded to each other and whole tissue specimens. Biopsy results were compared to whole tissue specimens. RESULTS: Specimens were obtained from 60 radical and 46 partial nephrectomy cases. Malignant neoplasms were present in 91 cases (86%). Overall, 15 cases (14%) were benign, of which 11 were oncocytomas. If lesions 4 cm. or less only were included in analysis, the incidence of benign lesions increased to 22%. Overall accuracy of the 2 pathologists was 76 and 80%. Nondiagnostic rates were 11 and 17%. Both observers incorrectly diagnosed 4 malignant lesions (5%) as benign, and incorrectly diagnosed 3 and 5 benign lesions (21 and 36%), respectively, as malignant. Analysis of values for both observers yielded a sensitivity of 77 and 84%, specificity 60 and 73%, positive predictive value 94 and 96%, and negative predictive value 69 and 73%. CONCLUSIONS: Overall frozen needle biopsy was accurate in more than 75% of cases and showed an excellent positive predictive value for carcinoma of more than 94%. Unfortunately, there was a large degree of inaccuracy for benign lesions and we do not recommend the routine use of intraoperative frozen needle biopsy to guide surgical decision making.

Leydig cell tumor of the testis: a clinicopathologic, DNA content, and MIB-1 comparison of nonmetastasizing and metastasizing tumors.

Leydig cell tumors of the testis are rare and account for a small proportion of testicular neoplasms. The objective of this study was to identify clinical and morphologic features predictive of metastasis in a large series of Leydig cell tumors, and to determine whether ploidy or proliferative activity were predictive of malignancy. Thirty cases of Leydig cell tumor of the testis (23 tumors that had not metastasized and 7 that had metastasized) were studied. Clinical history and follow-up were collected in all cases. The morphologic features examined included tumor size, mitotic index (mitotic figures/10 high-power fields), necrosis, angiolymphatic invasion, cell type, tumor-testicle interface, presence of extension beyond the testicular parenchyma, and presence of lipochrome and Reinke crystals. Most patients (93%) had a testicular mass. Patients with Leydig cell tumors that metastasized were diagnosed at a mean age of 62 years (range, 39-70 years) compared with 48 years (range, 9-79 years) in patients with nonmetastasizing tumors (p = 0.25). Leydig cell tumors that metastasized were significantly larger than nonmetastasizing tumors (mean, 4.7 versus 2.6 cm, respectively; p = 0.008), and had a significantly higher mitotic index (mean, 13.9 versus 1.9, respectively; p < 0.0001). Metastasizing Leydig cell tumors were significantly associated with atypical mitotic figures (p < 0.0001), nuclear variation (p = 0.0025), necrosis (p < 0.0001), angiolymphatic invasion (p = 0.009), infiltrative margins (p < 0.0001), high grade (p = 0.0004), and invasion into rete testis, epididymis, or tunica (p = 0.001) when compared with nonmetastasizing tumors. There was no significant difference between metastasizing and nonmetastasizing tumors in regard to cell type, lipochrome content, presence of Reinke crystals, or nuclear inclusions. All Leydig cell tumors that metastasized and 7 of 18 (38.9%) nonmetastasizing tumors were DNA aneuploid by static image analysis (p = 0.02). Metastasizing Leydig cell tumors had a significantly higher mean MIB-1 activity of 18.6% (range, 5.8-33.6) compared with 1.2% (range, 0.04-8.2) in nonmetastasizing tumors (p = 0.001). In this study, the presence of cytologic atypia, necrosis, angiolymphatic invasion, increased mitotic activity, atypical mitotic figures, infiltrative margins, extension beyond the testicular parenchyma, DNA aneuploidy, and increased MIB-1 activity were significantly associated with metastatic behavior in Leydig cell tumors.