The influence of nodal yield in neck dissections on lymph node ratio in head and neck cancer.

OBJECTIVES: Recent studies suggest that lymph node ratio (LNR) is a strong prognostic factor in head and neck cancer. This study aims to determine if the yield of harvested lymph nodes (LNs) influences the LNR. METHODS: The study included 522 head and neck cancer patients, undergoing 638 primary and salvage (selective) neck dissections between 2002 and 2012. Before 2007 the neck dissection specimens were macroscopically and microscopically examined by pathologists and after 2007 the macroscopic examination was performed by pathology technicians. For comparison of mean LN yields, univariate and multivariate analyses were performed. RESULTS: The mean number of LNs among 374 specimens examined by pathologists was 24 (range 0-89) vs. 32 (range 2-89) among 264 specimens examined by pathology technicians (P<.001). This caused the mean LNR in the non pre-treated patient group to drop from 11.4% to 8.7%. The counts of LNs per type of neck dissection were significantly different and increased with the number of levels involved. However, there was no linear relationship and the higher yields could be mostly ascribed to LNs in level V. The LNR varied from 8.1% to 18.4% among the different types of neck dissections. CONCLUSIONS: A significant increase in the number of harvested LNs, but a decrease in LNR was observed after introducing pathology technicians for macroscopic examination. A clear association between the extent of the dissection and the number of harvested LNs was observed. LNR appears to be strongly dependent on the harvesting protocol and the extent of the dissection.

Pharmacokinetics of altrenogest in horses.

The Federation Equestre Internationale has permitted the use of altrenogest in mares for the control of oestrus. However, altrenogest is also suspicious to misuse in competition horses for its potential anabolic effects and suppression of typical male behaviour, and thus is a controlled drug. To investigate the pharmacokinetics of altrenogest in horses we conducted an elimination study. Five oral doses of 44 mug/kg altrenogest were administered to 10 horses at a dose interval of 24 h. Following administration blood and urine samples were collected at appropriate intervals. Altrenogest concentrations were measured by liquid chromatography-tandem mass spectrometry. The plasma levels of altrenogest reached maximal concentrations of 23-75 ng/mL. Baseline values were achieved within 3 days after the final administration. Urine peak concentrations of total altrenogest ranged from 823 to 3895 ng/mL. Twelve days after the final administration concentrations were below the limit of detection (ca 2 ng/mL).

Assay of tryptophan decarboxylase from Catharanthus roseus plant cell cultures by high-performance liquid chromatography.

An assay is described for the enzyme tryptophan decarboxylase from plant cell suspension cultures. It is based on the fluorometric detection of tryptamine by HPLC on a LiChrosorb RP-8 Select B column. Tryptophan decarboxylase from Catharanthus roseus was induced by transferring 14-day-old cells into an induction medium. Optimum activity was found 2 days after transfer, the increase being 5- to 10-fold. When kept at -15 degrees C the crude enzyme lost half its activity in about 7 days. The rate of the decarboxylation reaction was linear for at least 3 h at 35 degrees C.