Cardiovascular collapse during anesthesia in a patient with preoperatively discontinued chronic MAO inhibitor therapy

We describe a patient in whom long-term monoamine oxidase (MAO) inhibitor therapy was discontinued 20 days before surgery with general anesthesia. This patient developed severe perioperative hypotension after administration of 10 mg of bupivacaine through an epidural catheter, which was corrected only after potent vasopressor therapy. We attribute this hemodynamic instability to attenuation of this patient's sympathetic tone based on several mechanisms: (1) residual effect of long-term administration of MAO inhibitor that caused a decrease in the number of β-adrenergic receptors (adrenergic subsensitivity due to receptor down-regulation), (2) recovered MAO activity causing effective degradation of sympathetic amines, and (3) combined attenuating effects of general and epidural anesthesia on sympathetic tone.     

Morphology of developing olfactory axons in the olfactory bulb of the rabbit (Oryctolagus cuniculus): a Golgi study

Transient expression of axon collaterals plays an important role in enabling neurons to find appropriate targets during development. In the olfactory bulb, the numbers of both sensory neurons and their targets, the glomeruli, increase markedly during the postnatal period. In the present study, the morphology of developing olfactory axons in the olfactory bulb of 1-21-day-old rabbits was analyzed using stereological methods and the rapid Golgi technique. The findings demonstrated a change in axon morphology from the olfactory nerve layer to the glomeruli suggestive of a sequence in axon development. In the olfactory nerve layer, axons typically had knob-like growth cones and a few collateral branches. Close to glomeruli, axons increased in thickness, formed rather complex and irregular growth cones, and typically gave off many collaterals. Within glomeruli, the axons formed terminal branches and boutons. Extraglomerular branches were apparently removed once axons had entered a glomerulus, insofar as these branches often displayed morphological signs of degeneration. In contrast, collateral branches ending in the same glomerulus remained, indicating that formation of collaterals may assist olfactory axons in locating glomerular targets.     

Dynamic real-time subtraction of stray-light and background for multiphoton imaging

We introduce a new approach to reduce uncorrelated background signals from fluorescence imaging data, using real-time subtraction of background light. This approach takes advantage of the short fluorescence lifetime of most popular fluorescent activity reporters, and the low duty-cycle of ultrafast lasers. By synchronizing excitation and recording, laser-induced multiphoton fluorescence can be discriminated from background light levels with each laser pulse. We demonstrate the ability of our method to – in real-time – remove image artifacts that in a conventional imaging setup lead to clipping of the signal. In other words, our method enables imaging under conditions that in a conventional setup would yield corrupted data from which no accurate information can be extracted. This is advantageous in experimental setups requiring additional light sources for applications such as optogenetic stimulation.     

Histopathological and clinical findings in renal transplants with Banff type II and III acute cellular rejection without tubulointerstitial infiltrates

According to the Banff guidelines for renal transplants, pure endothelialitis without any tubulointerstitial infiltrates (with the Banff components v?≥?1, i0, t0) has to be called acute cellular rejection (ACR). The pathophysiology of this rare lesion abbreviated as v_only is currently unclear, as well as its clinical, serological, and prognostic implications. Therefore, we conducted this retrospective comparative study. We compared all 23 biopsies with v_only from Hannover Medical School between 2003 and 2010 with 23 matched biopsies with the Banff components v?≥?1, i?≥?1, and t?≥?1 (v_plus) and 23 biopsies with v0, i0, and t0 (v0i0t0). Serological (available in 10, 11, and 14 patients, respectively), histological, and clinical data were compared. Of all biopsies, 0.4 % had findings of v_only. v_only, v_plus, and v0i0t0 only showed minimal differences in the Banff components apart from the cohort-defining components. Endothelialitis in v_only more frequently involved the arcuate arteries than the smaller preglomerular vessels compared to v_plus and vice versa. Combining histopathological data and serological data, v_only more frequently showed criteria for acute humoral rejection than v0i0t0 (albeit not persistent after the Bonferroni–Holm correction in pairwise comparisons), while there was no difference between v_only and v_plus. No difference could be demonstrated regarding clinical presentation at biopsy or outcome. Our results show minimal differences regarding clinical presentation, outcome, and histological features between v_only and v_plus. Patients with v_only should be thoroughly investigated for evidence of acute humoral rejection.     

Squamous cell carcinoma of the oropharynx: Ki-67 and p53 can identify patients at high risk for local recurrence after surgery and postoperative radiotherapy

PURPOSE: To assess the prognostic value of biologic (p53, Ki-67) and clinical factors in squamous cell carcinoma of the oropharynx after radical surgery and postoperative radiotherapy (RT). METHODS AND MATERIALS: Between 1985 and 1995, a total of 102 patients with 104 tumor sites were entered onto the study. Fifty-five primary tumors (53%) involved the tonsils, 26 (25%) the soft palate, and 23 (22%) the base of the tongue. Median age was 53 years (range 36-80 years). The clinical T- and N-categories (UICC 1997) were: T1 (30), T2 (47), T3 (22), T4 (5), N0 (33), N1 (28), N2 (42), and N3 (1). Histologically-clear margins were achieved in all patients by initial surgery. Postoperative RT to the primary and regional lymphatics was given, to a total of 60 Gy in 6 weeks, and single daily fractions of 2 Gy. The expression of the nuclear p53- and Ki-67-labeling index (LI) was investigated by immunostaining using the monoclonal antibodies DO-7 and MIB 1. The nuclear p53-intensity (p53-I) was graded into 4 categories (0/+/++/) by densitometry. Median follow-up was 43 months (range 14-132 months). RESULTS: Cancer-specific survival, disease-free survival, and locoregional tumor control rates were 74%, 69%, and 75%, respectively, at 5 years. Significant prognostic factors for disease-free survival were: T-category (T1/2: 77% vs. T3/4: 53%, p = 0.02), tumor site (tonsils: 79% vs. soft palate: 70% vs. base of tongue: 45%, p = 0.05), duration of RT (< or = 46 days: 80% vs. > 46 days: 60%, p = 0.04), Ki-67 LI (< or = 20%: 84% vs. > 20%: 49%, p = 0.006) and p53-I (0/+: 56% vs. ++/ : 79%, p = 0.008). A significant prognostic impact on locoregional control was noted for the duration of RT (< or = 46 days: 86% vs. > 46 days: 68%, p = 0.01), tumor site (tonsils: 88% vs. soft palate: 67% vs. base of tongue: 51%, p = 0.02), Ki-67 LI (< or = 20% LI: 87% vs. > 20% LI: 56%, p = 0.018), and the p53-I (0/+: 58% vs. ++/ : 88%, p = 0.0006). On multivariate analysis, the p53 nuclear intensity (p = 0.002) and the Ki-67 index (p = 0.01) remained the only significant factors for locoregional control. CONCLUSION: Ki-67 labeling index above 20% and a weak p53 nuclear intensity (0/+) are both able to identify patients with squamous cell carcinoma of the oropharynx being at high risk for local recurrence after surgery and postoperative RT. Consequently, in this subgroup an intensification of treatment may be contemplated in prospective trials.     

Individual Radiosensitivity Does not Correlate with Radiation-Induced Apoptosis in Lymphoblastoid Cell Lines or CD3+ Lymphocytes

Background and Purpose:   

Spontaneous and radiation-induced apoptosis of lymphoblastoid cell lines (LCLs) derived from healthy donors, cancer patients and donors with radiosensitivity syndromes as well as CD³⁺ lymphocytes from patients with grade 3 late toxicity were investigated as a possible marker for the detection of individual radiosensitivity. These investigations are based on the hypothesis that hypersensitive patients have reduced levels of apoptosis after in vitro irradiation as a result of a defect in the signaling pathway.     

Insecticide has asymmetric effects on two tadpole species despite priority effects

Priority effects are defined as asymmetric responses of different species colonizing the same habitat in different sequences and are important in structuring communities, particularly for ephemeral systems that are colonized annually. Amphibians often use ephemeral ponds and have been shown to experience priority effects from interspecific competition. Pesticide exposure can impact amphibian species interactions like competition, and has been linked to declines. We investigated whether insecticide exposure interacted with colonization history to impact priority effects in Bufo americanus and Rana pipiens. We predicted that exposure to the insecticide carbaryl and colonization history would affect tadpole metamorphosis independently and interactively. Our results indicated that Bufo time to metamorphosis experienced priority effects: Bufo introduced early reached metamorphosis sooner when Rana were absent, but Bufo introduced late reached metamorphosis sooner when Rana were also late. Insecticide exposure eliminated differences in Bufo time to metamorphosis due to Rana colonization history. Rana survival and mass at metamorphosis were affected by intraspecific colonization history. Bufo had significantly fewer survivors and Rana had more survivors in insecticide-exposed treatments. Bufo did better when reared without Rana, but Rana was unaffected by Bufo presence. The effects on anuran metamorphosis occurred without any effects on periphyton abundance. We suggest that the effects of insecticide exposure on amphibian metamorphosis are not related to colonization history, although each factor alone can have substantial impacts. These results preliminarily suggest that managing pesticide applications with sensitivity to amphibians may be less complex than implied by traditional food web theory, although more research is needed.     

A re-estimation of the number of glomeruli and mitral cells in the olfactory bulb of rabbit

Although morphological characteristics of mammalian olfactory bulb (OB) are well documented in rodents (rat, mice), only one study has been performed in rabbit, which is also commonly used in olfactory research. The study carried out by Allison and Warwick in 1949 led to surprising results still quoted in recent literature. The present study re-examined this question in young rabbit OB, while it was also conducted with rat as control. In five animals of each species, areas and coordinates of glomeruli and mitral profiles were measured in 10 coronal sections uniformly distributed along the rostrocaudal axis of the OB, and a distribution-free stereological method was used to compute values along this axis. For glomeruli, the estimated number was 4200 in rat and 6300 in rabbit. While this estimation matched with those found in literature in rat, it strikingly differed from the Allison and Warwick's value of 1900 only. For mitral cell number, we found 59,600 while the preceding study found 45,000 only. In contrast to the number of glomeruli, the mitral cell number in rat and rabbit were very close. Indeed, results showed 56,200 in rat. The results suggest that the numbers of olfactory glomeruli and mitral cells has been previously underestimated in rabbit, and that the number of glomeruli changes as a function of species. In addition, both the results of the present study and reports in the literature suggest the number of mitral cells to be rather similar in mouse, rat and rabbit. As a consequence, the glomerular/mitral cell ratio is likely to varied in a wide range across species.