Longitudinal Outcomes of Malignant Ureteral Obstruction Secondary to Ovarian Cancer: Predictors of Resolution and the Role of Surgical Management

OBJECTIVE

To review the management of ovarian cancer (OCa) associated hydronephrosis (HN). Specifically, we aim to identify optimal management of HN in the acute setting, predictors of HN resolution, and the role of surgery (tumor debulking/(+/-)ureterolysis/hysterectomy).

MATERIALS/METHODS

The study cohort included OCa patients managed at our institution from 2004-2019 that developed OCa-associated HN. Initial HN management was recorded as none, retrograde ureteral stent (RUS) or percutaneous nephrostomy tube (PCN). Primary outcomes included (1) HN management failure, (2) HN management complications, and (3) HN resolution. Patient, cancer, and treatment predictors of outcomes were assessed using logistic regression and fine-Gray competing risk models.

RESULTS

Of 2580 OCa patients, 190 (7.4%) developed HN. HN was treated in 121; 90 (74.4%) with RUS, 31 (25.6%) with PCN. Complication rates were similar between PCN and RUS (83% vs 85.1%; P = .79; all Clavian Grade I/II). Initial HN treatment failure occurred in 28 patients, predicted by renal atrophy (hazard ratios (HR) 3.27, P <.01). HN resolution occurred in only 52 (27%) patients and was predicted by lower International Federation of Gynecology and Obstetrics (FIGO) stage (FIGO III/IV HR 0.42, P <.01) and surgical tumor debulking/ureterolysis (HR 2.83, P = .02).

CONCLUSION

Resolution of HN associated with malignant obstruction from OCa is rare and is most closely associated with tumor debulking and International Federation of Gynecology and Obstetrics (FIGO) stage. Initial endoscopic treatment modality was not significantly associated with complications or resolution, though RUS failures were slightly more common. Ureteral reconstruction at time of debulking/ureterolysis is potentially underutilized.

Development of Seven New dPCR Animal Species Assays and a Reference Material to Support Quantitative Ratio Measurements of Food and Feed Products

Laboratory testing methods to confirm the identity of meat products and eliminate food fraud regularly rely on PCR amplification of extracted DNA, with most published assays detecting mitochondrial sequences, providing sensitive presence/absence results. By targeting single-copy nuclear targets instead, relative quantification measurements are achievable, providing additional information on the proportions of meat species detected. In this Methods paper, new assays for horse, donkey, duck, kangaroo, camel, water buffalo and crocodile have been developed to expand the range of species that can be quantified, and a previously published reference assay targeting the myostatin gene has been modified to include marsupials and reptiles. The accuracy of this ratio measurement approach was demonstrated using dPCR with mixtures of meat DNA down to 0.1%. However, the limit of detection (LOD) of this approach is not just determined by the assay targets, but by the samples themselves, with food or feed ingredients and processing impacting the DNA yield and integrity. In routine testing settings, the myostatin assay can provide multiple quality control roles, including monitoring the yield and purity of extracted DNA, identifying the presence of additional meats not detected by the suite of species-specific assays and potentially estimating a sample-specific LOD based on measured copy numbers of the myostatin target. In addition to the myostatin positive control assay, a synthetic DNA reference material (RM) has been designed, containing PCR targets for beef, pork, sheep, chicken, goat, kangaroo, horse, water buffalo and myostatin, to be used as a positive template control. The availability of standardised measurement methods and associated RMs significantly improves the reliability, comparability and transparency of laboratory testing, leading to greater confidence in results.

Ca2+-saturated calmodulin binds tightly to the N-terminal domain of A-type fibroblast growth factor homologous factors

Voltage-gated sodium channels (Na_vs) are tightly regulated by multiple conserved auxiliary proteins, including the four fibroblast growth factor homologous factors (FGFs), which bind the Na_v EF-hand like domain (EFL), and calmodulin (CaM), a multifunctional messenger protein that binds the Na_V IQ motif. The EFL domain and IQ motif are contiguous regions of Na_V cytosolic C-terminal domains (CTD), placing CaM and FGF in close proximity. However, whether the FGFs and CaM act independently, directly associate, or operate through allosteric interactions to regulate channel function is unknown. Titrations monitored by steady-state fluorescence spectroscopy, structural studies with solution NMR, and computational modeling demonstrated for the first time that both domains of (Ca²⁺)₄-CaM (but not apo CaM) directly bind two sites in the N-terminal domain (NTD) of A-type FGF splice variants (FGF11A, FGF12A, FGF13A, and FGF14A) with high affinity. The weaker of the (Ca²⁺)₄-CaM-binding sites was known via electrophysiology to have a role in long-term inactivation of the channel but not known to bind CaM. FGF12A binding to a complex of CaM associated with a fragment of the Na_V1.2 CTD increased the Ca²⁺-binding affinity of both CaM domains, consistent with (Ca²⁺)₄-CaM interacting preferentially with its higher-affinity site in the FGF12A NTD. Thus, A-type FGFs can compete with Na_V IQ motifs for (Ca²⁺)₄-CaM. During spikes in the cytosolic Ca²⁺ concentration that accompany an action potential, CaM may translocate from the Na_V IQ motif to the FGF NTD, or the A-type FGF NTD may recruit a second molecule of CaM to the channel.

Pharmacokinetics and metabolism of14C-1,3-dichloropropene in the Fischer 344 rat and the B6C3F1mouse

1. 14C-1,3-dichloropropene (14C-DCP) is rapidly absorbed and eliminated in both the male F344 rat and B6C3F1 mouse following oral administration of 1 or 50 mg kg(-1) (rat) or 1 or 100 mg kg(-1) (mouse). 2. It is extensively metabolized in both species. Urinary excretion was the major route of elimination, accounting for 50.9-61.3 and 62.5-78.6% of the administered dose in rat and mouse, respectively. 3. Urinary elimination half-lives ranged from 5 to 6 h (rat) and from 7 to 10 h (mouse). Elimination via faeces or as 14CO2 accounted for 14.5-20.5 and 13.7-17.6% of the administered dose, respectively. 4. Metabolites arising from glutathione conjugation account for 36-55 and 48-50% of the administered dose in excreted from rats and mice, respectively. Hydrolysis of the 3-chloro moiety of DCP accounted for 24-37 and 29% of the dose administered to rats and mice, respectively. Two novel dimercapturic acid conjugates were also identified at low levels that might arise via initial hydrolysis of DCP or of epoxidation of DCP-glutathione conjugate or of DCP itself. Structural confirmation of these dimercapturates was obtained via analysis of deuterium retention from D4-DCP in the male F344 rat. 5. Only quantitative differences are seen between the overall metabolic profile of DCP in these two species.

Age and Dose Dependency of the Pharmacokinetics and Metabolism of Bisphenol A in Neonatal Sprague-Dawley Rats Following Oral Administration

Previous studies demonstrated the rapid clearance of bisphenol A (BPA) from blood following oral administration to adult rats with the principal metabolite being BPA-monoglucuronide (BPA-glucuronide). Since the ontogeny of glucuronyl transferases (GT) differs with age, the pharmacokinetics of BPA were studied in neonatal animals. (14)C-BPA was administered via gavage at 1 or 10 mg/kg body weight to rats at postnatal day (pnd) 4, pnd 7, pnd 21, or to 11 week old adult rats (10 mg/kg dose only). Blood (neonates and adults) and selected tissues (neonates) were collected at 0.25, 0.75, 1.5, 3, 6, 12, 18, and 24 h postdosing. BPA and BPA-glucuronide in the plasma were quantified by high-performance liquid chromatography; radioactivity in the plasma and tissues was quantified by liquid scintillation spectrometry. The data indicate that neonatal rats at all three ages metabolized BPA to BPA-glucuronide, although an age dependency in the number and concentration of plasma metabolites was observed, consistent with the ontogeny of GT. BPA-glucuronide and BPA concentrations in the plasma were greater in neonates than in adults, except at 24 h postdosing, suggesting an immaturity in the development of hepatic excretory function in neonatal rats. Nevertheless, the half-lives for the elimination of BPA-glucuronide in plasma were more rapid in neonatal animals than in adults, likely due to reduced microflora beta-glucuronidase activity and an absence of enterohepatic recirculation. A dose dependency in the metabolism and pharmacokinetics of BPA administered to neonates was also observed with nearly complete metabolism of BPA to BPA-glucuronide (94-100% of the plasma radioactivity) at a dose of 1 mg/kg. This was in contrast to finding up to 13 different plasma metabolites observed at the 10 mg/kg dose. These data indicate that, from early in neonatal life through pnd 21, there is sufficient GT activity in rats to efficiently metabolize BPA to its nonestrogenic metabolite at low doses.

Metabolism and pharmacokinetics of bisphenol A (BPA) and the embryo-fetal distribution of BPA and BPA-monoglucuronide in CD Sprague-Dawley rats at three gestational stages

The pharmacokinetics of bisphenol A (BPA), including the quantification of the major BPA metabolite BPA-monoglucuronide conjugate (BPA-glucuronide) was studied in Sprague-Dawley rats at different stages of gestation. 14C-BPA was administered orally at 10 mg BPA/kg body weight (0.2 mCi/rat) to nongravid rats and to other groups on gestation days (GD) 6, 14, and 17. GD 0 was when the vaginal smear was sperm positive or a copulatory plug was observed. Radioactivity derived from 14C-BPA was quantified in the maternal blood, selected tissues, and the embryo or fetus. BPA and BPA-glucuronide were quantified in maternal plasma and excreta. Additional rats were dosed orally at 10 mg 14C-BPA/kg (0.2 mCi/rat or 0.5 mCi/rat) on GD 11, 13, and 16 to further study the distribution of BPA and BPA-glucuronide to the embryo/fetal tissue. The tissue distribution, metabolism, or the rates or routes of excretion of BPA, or the plasma concentration-time profiles of BPA-glucuronide did not appear to be altered at any stage of gestation as compared to nonpregnant rats. In the GD 11 group, neither BPA nor BPA-glucuronide was detected in the yolk sacs or embryos, except for trace concentrations of BPA-glucuronide in the yolk sacs at 15 min postdosing. In the GD 13 group, both BPA and BPA-glucuronide were detected in the yolk sacs of the conceptus but not in the embryos/fetuses, except for BPA at 15 min. For the animals dosed with 0.2 mCi/rat on GD 16, both analytes were detected in the placentae at 15 min and 12 h, but not at 96 h. Traces of both analytes were detected in fetal tissue in two of five specimens at 15 min only. In rats dosed on GD 16 with 0.5 mCi/rat, the BPA-glucuronide and BPA concentrations in maternal plasma at 15 min were 1.7 and 0.06 mug equivalents (eq)/g plasma, respectively. At the same time postdosing in these animals, the placental BPA-glucuronide concentrations were lower (0.34 mug eq BPA [as glucuronide]/g), and the BPA concentrations were about equivalent (0.095 mug/g). Fetal BPA-glucuronide and BPA concentrations were markedly lower, 0.013 and 0.018 mug eq/g, respectively. Therefore, no selective affinity of either yolk sac/placenta or embryo/fetus for BPA or BPA metabolites relative to maternal plasma or tissues was observed in this study.

Significance of 2-methoxypropionic acid formed from beta-propylene glycol monomethyl ether: integration of pharmacokinetic and developmental toxicity assessments in rabbits

Commercial grade propylene glycol monomethyl ether (PGME), which is composed of > 99.5% alpha-isomer and < 0.5% beta-isomer, has been shown in several studies to have a low potential for developmental toxicity. Nonetheless, questions have been raised about potential human developmental toxicity due to beta-PGME, because it can be metabolized to 2-methoxypropionic acid (MPA), a compound bearing structural similarity to the teratogen, methoxyacetic acid (MAA). Accordingly, a series of in vivo developmental toxicity, whole embryo culture, and in vivo pharmacokinetic experiments were conducted in New Zealand White rabbits (highly sensitive to these compounds) to better understand the developmental toxicity potential of MPA and the kinetics of its formation from beta-PGME. For the in vivo developmental toxicity studies, groups of 20 inseminated rabbits were gavaged with 0, 10, 26, or 78 mg/kg/day of MPA on gestation day (GD) 7-19, followed by fetal evaluation on GD 28. Results with MPA were compared with those of rabbits similarly dosed with 0, 2.5, 7.5, or 15 mg/kg/day of MAA. Developmental toxicity no-observable-effect levels (NOEL) were approximately 10-fold higher for MPA (26 mg/kg/day) than for MAA (2.5 mg/kg/day). Also, the severity of effects caused by MPA was less than that of MAA, and unlike MAA, MPA was not selectively toxic to the fetus. This differential toxicity was also seen in whole embryo cultures of GD 9 rabbit embryos, in which there were no adverse effects of MPA (1.0, 5.0 mM) or its parent compound, beta-PGME (0.5, 2.0 mM), but severe dysmorphogenesis in 100% of embryos cultured in 5.0 mM MAA. The pharmacokinetics study showed rapid and complete conversion of beta-PGME to MPA, with a relatively long elimination half-life (33-44 h) for MPA. However, peak and AUC concentrations of MPA in blood associated with the MPA LOEL dose of 78 mg/kg/day were 1.3 mM and 52.9 mM-h/l, respectively, suggesting a relatively high threshold based on internal dosimetry. Taken together, these data indicate a negligible risk of developmental toxicity due to MPA formation from the small amounts of beta-isomer present in commercial PGME.

The relative bioavailability and metabolism of bisphenol A in rats is dependent upon the route of administration

Bisphenol A (BPA) is used to produce polymers for food contact applications, thus there is potential for oral exposure of humans to trace amounts via the diet. BPA was weakly estrogenic in screening assays measuring uterine weight/response, although much higher oral doses of BPA were required to elicit a uterotropic response as compared to other routes of administration. The objective of this study was to determine if a route dependency exists in the pharmacokinetics and metabolism of 14C-labeled BPA following single oral (po), intraperitoneal (ip), or subcutaneous (sc) doses of either 10 or 100 mg/kg to Fischer 344 rats. Results indicated a marked route dependency in the pharmacokinetics of BPA. The relative bioavailability of BPA and plasma radioactivity was markedly lower following oral administration as compared to sc or ip administration. The major fraction of plasma radioactivity following oral dosing was the monoglucuronide conjugate of BPA (68-100% of plasma radioactivity). BPA was the major component in plasma at Cmax following sc or ip administration exceeded only by BPA-monoglucuronide in females dosed ip. Up to four additional unidentified metabolites were present only in the plasma of animals dosed ip or sc. One of these, found only following ip administration, was tentatively identified as the monosulfate conjugate of BPA. The monoglucuronide conjugate was the major urinary metabolite; unchanged BPA was the principal component excreted in feces. These results demonstrated a route dependency of BPA bioavailability in rats, with oral administration resulting in the lowest bioavailability, and offer an explanation for the apparent route differences in estrogenic potency observed for BPA.

Pharmacokinetics and metabolism of triclopyr in the crayfish (Procambarus clarki)

Crayfish (Procambarus clarki) were exposed to [14C]triclopyr at concentrations of 1 and 2.5 mg/liter, similar to potential field applications. Following 11 days of exposure, the elimination of accumulated residues was followed for 36 days. The majority of the residue in whole crayfish was present in the carcass (shell, hemolymph). HPLC of hepatopancreas showed the residues were primarily parent triclopyr (greater than 80%). The principle metabolite in the hepatopancreas was confirmed by mass spectrometry as the taurine conjugate of triclopyr. Several minor metabolites also were present at very low levels (less than 0.1 ppm) and were not identified. Residues were eliminated with half-lives of 7 to 17 days, depending on the tissue and exposure concentration. Bioconcentration factors, estimated from uptake and elimination rate constants determined using a compartmental model, were about 1 in whole crayfish and hepatopancreas and about 0.2 in muscle. The results of this study indicate that there is a low potential for accumulation of triclopyr and its metabolites in the crayfish.

Toxicological evaluation of food additives. Toxicological evaluation over estimation of potential high intake to permitted levels of use of food additives and vice versa

Permitted levels of use for food additives should agree with the acceptable daily intakes (ADIs) established by toxicologists. To ensure accordance, nutritional and physiological factors can be used to estimate high intakes of food and beverages. Appetite and thirst (energy and liquid requirements) are such quantitative factors. They are universal and, if placed on the same level as the ADI, i.e., expressed on a kilogram of body weight basis, can be used to estimate high intakes of an additive. This tool can be easily used to judge whether a suggested level of use may cause consumption of the additive to exceed the ADI. It also tells us to what level (ADI) toxicological clearance should be sought, when the technological need is known. The method is independent of food consumption surveys, but these may be carried out to confirm its forecasts. This paper uses caramel in soft drinks as an example. The approach, also called "the budget method," has been tried out in Denmark and Sweden. It is now being offered as a solution to the problem facing the European Communities: to establish before 1993 a common list of food additives containing quantitative limitations for use.

Unusual presentation of severe hypoglycemia

An unusual case of severe hypoglycemia during which a patient was awake and able to walk despite a serum glucose concentration of 10 mg/dl (0.55 mmol/l) is reported. No tumor was found at autopsy, and the patient was not diabetic. Repeat glucose determinations on the initial as well as subsequent blood samples and a mixing study were performed to exclude interference and sampling or analytic error. The discrepancy between the clinical status of the patient and the degree of hypoglycemia remains an enigma.