The prognostic impact of the extent of lymph node dissection in patients with stage III melanoma.

AIMS: To analyse disease-free and overall survival in 67 melanoma patients who underwent dissection for clinically apparent regional lymph node metastases, taking into account the total number of excised lymph nodes. METHODS: After a median follow-up time of 16 months, 47 recurrences were observed and 43 patients died. The median disease-free and overall survival intervals were 14 and 24 months respectively. RESULTS: Multivariate analyses revealed that the number of excised lymph nodes had a significant impact on overall survival (P=0.036) but not on disease-free survival (P=0.97). Extranodal growth was the only statistically significant prognostic factor both for disease-free (P=0.005) and overall (P=0.038) survival. Age, nodal basin, primary tumor ulceration, tumor thickness and number of positive lymph nodes were not significant prognostic factors. CONCLUSIONS: Our results suggest that the total number of lymph nodes excised in the dissection has impact on overall survival of stage III melanoma patients and should be considered in clinical assays.     

Type B aortic dissection complicating renal artery angioplasty and stent placement

Percutaneous renal artery stent placement has been demonstrated to improve blood pressure control and stabilize renal function in patients with atherosclerotic renal artery disease. However, this procedure is not without risk of significant morbidity, and its effectiveness, as compared to alternative treatments, has not been adequately established. The authors report a case of acute type B aortic dissection complicating renal artery stent placement. The authors postulate that an intimal disruption occurred during initial balloon angioplasty, and that repeated application of radial, shear, and torque forces during stent placement may have extended the injury. The diagnosis of acute aortic dissection should be considered in patients with suggestive symptoms immediately after stent placement.     

High prevalence of HIV infection among homeless and street-involved Aboriginal youth in a Canadian setting

Aboriginal people experience a disproportionate burden of HIV infection among the adult population in Canada; however, less is known regarding the prevalence and characteristics of HIV positivity among drug-using and street-involved Aboriginal youth. We examined HIV seroprevalence and risk factors among a cohort of 529 street-involved youth in Vancouver, Canada. At baseline, 15 (2.8%) were HIV positive, of whom 7 (46.7%) were Aboriginal. Aboriginal ethnicity was a significant correlate of HIV infection (odds ratio = 2.87, 95%CI: 1.02 – 8.09). Of the HIV positive participants, 2 (28.6%) Aboriginals and 6 (75.0%) non-Aboriginals reported injection drug use; furthermore, hepatitis C co-infection was significantly less common among Aboriginal participants (p = 0.041). These findings suggest that factors other than injection drug use may promote HIV transmission among street-involved Aboriginal youth, and provide further evidence that culturally appropriate and evidence-based interventions for HIV prevention among Aboriginal young people are urgently required.     

Evidence for endogenous formation of tobacco-specific nitrosamines in rats treated with tobacco alkaloids and sodium nitrite

Carcinogenic tobacco-specific nitrosamines are present in tobacco products and are believed to play a significant role in human cancers associated with tobacco use. Additional amounts of tobacco-specific nitrosamines could be formed endogenously. We tested this hypothesis by treating rats with nicotine and sodium nitrite and analyzing their urine. Initially, we treated groups of rats with (S)-nicotine (60 micromol/kg) and NaNO2 (180 micromol/kg), (S)-nicotine alone, NaNO2 alone or 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK, 12 nmol/kg) by gavage twice daily for 4 days. We collected urine and analyzed for two metabolites of NNK; 4-(methylnitrosamino)-1-(3- pyridyl)-1-butanol and its glucuronide. We did not detect these metabolites in the urine of rats treated with nicotine alone or nicotine plus NaNO2, indicating that endogenous conversion of nicotine to NNK did not occur. However, the urine did contain N'- nitrosonornicotine (NNN), N'-nitrosoanabasine (NAB) and N'- nitrosoanatabine (NAT). Analysis of the (S)-nicotine used in this experiment demonstrated that it contained trace amounts of nornicotine, anabasine and anatabine. In a second experiment, we used an identical protocol to compare the endogenous nitrosation of this (S)-nicotine with that of synthetic (R,S)-nicotine, which did not contain detectable amounts of nornicotine, anabasine or anatabine. NNN (0.53 x 10(-3)% of nicotine dose), NAB (0.68%) and NAT (2.1%) were detected in the urine of the rats treated with the (S)-nicotine and NaNO2. NNN (0.47 x 10(- 3)% of dose), but not NAB or NAT, was present in the urine of the rats treated with synthetic (R,S)-nicotine and NaNO2. NNN probably formed via nitrosation of metabolically formed nornicotine. These results demonstrate for the first time that endogenous formation of tobacco- specific nitrosamines occurs in rats treated with tobacco alkaloids and NaNO2. The potential significance of the results with respect to nitrosamine formation in people who use tobacco products or nicotine replacement therapy is discussed.      

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Training induced effects on blood volume,erythrocyte turnover and haemoglobin oxygen binding properties

Summary The effect of three weeks ergometer training (Tr) 5 times a week for 45 min at 70% by 6 subjects on erythrocyte turnover and haemoglobin O₂ affinity has been studied. Increased reticulocytosis could be observed from the second day after beginning Tr until a few days after its end, probably caused by increased erythropoietin release by the kidney. Erythrocyte destruction was most pronounced in the first and markedly reduced in the third week of Tr. Elevated glutamate oxalacetate transaminase activity and creatine as well as lowered mean corpuscular haemoglobin indicate a younger erythrocyte population in the first week of recovery. Total blood volume increased during the course of Tr by 700 ml, mainly caused by a raised plasma volume (74%). Red cell volume increased later with maximal values one week after Tr (+280 ml). In this week the standard oxygen dissociation curve was most shifted to the right (P₅₀ increased from 3.77±0.05 kPa to 3.99±0.07 kPa) and the Bohr coefficients had their lowest values. Both effects are completely explainable by the haemoglobin O₂ binding properties of young erythrocytes.After training, all parameters of physical performance ( , maximal workload, heart rate during rest and exercise) were markedly improved, indicating fast adaptation mechanisms. The increased erythrocyte turnover, including higher erythropoiesis, seems to be one important part of these effects.A preliminary report was presented at the National Congress of Sports Medicine in Cologne, 1982. Furthermore, the content of this paper was part of the doctoral thesis of the first author     

The effects of silymarin on experimental phalloidine poisoning.

The hepatoprotective action of silymarin, the active principle extracted from the fruit of Silybum marianum (L.) Gaertn., in animals (dogs, rabbits, rats, mice) intoxicated with phalloidine is evident, both after protective and curative treatment. A dose of 15 mg/kg of silymarin protects every animal when given 60 min before the toxin. When injected 10 mim after phalloidine, a dose of 100 mg/kg of silymarin again provides total protection. However, as the time span between administration of the toxic substance and start of treatment increases, so the efficacy of silymarin decreases; after 30 min its curative effect is negligible. The histochemical and histoenzymological studies show that during intoxication of the mice by phalloidine, silymarin inhibits the effect of the toxic substance and regulates the functions of the hepatocyte, when given either 60 min before or 10 min after phalloidine.     

Differential classical conditioning of abstinence syndrome in morphine-dependent rats

Independent groups of addicted rats were placed repeatedly in a conditioning procedure: pairings of non-rotatable activity wheels with periods of either 0–11 or 12–23 h of morphine deprivation. Controls consisted of a saline-injected group exposed to the same training stimuli and conditioning procedure, and a morphine addicted group not receiving such training. Subsequently, morphine-addicted animals were withdrawn until primary abstinence signs disappeared, and all groups were tested in unlocked wheels for differential activity resulting from reexposure to previous training environments.Experimental groups not only were found to exhibit significantly increased wheel turning over controls, but subjects having greater morphine deprivation during training were more resistant to extinction than a low deprivation group. Motivational interpretations and methodological artifacts in designs of this nature are discussed.A lengthy review of the literature encompassing the area of the present study, as well as a more thorough discussion of its theoretical aspects, were included in a Ph. D. thesis submitted to the Department of Psychology at the University of Denver, 1969, by the author.