Asterlingulatosides C and D, cytotoxic triterpenoid saponins from Aster lingulatus

Over the last few decades, European courses in which 'classical' tropical medicine (i.e. parasitology, entomology, and clinical aspects of tropical diseases) is taught have largely become anachronisms. Most countries in the tropics have their own medical schools and few have much need of expatriate doctors. There do, however, appear to be other ways in which Europeans may still help improve health in the tropics. One is to control the quality of the expatriate nurses who are still in demand in the tropics (often as cheaper, generally less demanding substitutes for doctors). This may be achieved by only training the best, insisting they spend some time after graduation gaining maturity before they leave for the tropics, ensuring they realise that their clinical skills will probably be inferior to their local counterparts in the tropics, and encouraging them to continue studying once abroad. The second way Europeans may help is to change the bias of their courses from teaching to training. There seems little doubt that the intellectual personalities of the brightest young men and women in the tropics often develop far better when they spend a period in a foreign environment, especially when they are allowed to function within a team, with trainees and trainers from other countries. Some 'international' courses may offer such benefits, especially if closely tailored to the needs of the trainees and their home countries.     

Transference in social perception: the role of chronic accessibility in significant-other representations

Research has shown that the activation and application of a significant-other representation to a new person, or transference, occurs in everyday social perception (S. M. Andersen & A. Baum, 1994; S. M. Andersen & S. W. Cole, 1990). Using a combined idiographic and nomothetic experimental paradigm, two studies examined the role of chronic accessibility of significant-other representations in transference. After learning about 4 fictional people, 1 of whom resembled a significant other, participants' recognition memory was assessed. Both studies showed greater false-positive memory in the significant-other condition, relative to control, even in the absence of priming. Study 2 showed that although the effect was greater when the significant-other representation was concretely applicable to the target information, it occurred even when no such applicability was present. Results implicate the chronic accessibility of significant-other representations in transference.     

Models for the effects of individual size and spatial scale on competition between species in heterogeneous environments

A spatially explicit model for competition with dispersal in a heterogeneous environment is used to study the effects of individual size and the spatial scale of the environment on the competitive interactions between species. The model is a Lotka-Volterra competition system with diffusion and with spatial variation in some coefficients. The coefficients in the model are taken to reflect a situation where the larger competitor typically disperses farther in unit time than the smaller and reproduces less rapidly, but has an advantage in contests or other forms of interference competition. The environment is assumed to be closed, i.e., it is assumed that individuals do not leave through the boundary. The environment is generally assumed to consist of a patch of favorable habitat surrounded by less favorable regions. The effects of spatial scale are studied by examining how the predictions of the model change as the size of the favorable patch is varied. The predictions turn out to be in qualitative agreement with the results of some empirical studies.     

Curative treatment for pancreatic neoplasms. Radical resection

The available data suggest that lymph node involvement is an important prognostic factor in patients with carcinoma of the head of the pancreas. Lymph node metastases occur in as many as 50% of the cases of even the smallest pancreatic cancers now being diagnosed and resected (i.e., those < 2 cm in diameter). There is some evidence, especially from clinical experience in Japan, that wider lymphatic dissections (i.e., wider than those commonly done with the standard Whipple resection) may prolong survival. Unfortunately, many of the available data around the world are retrospective and are not randomized between the standard and the radical operation. Moreover, the pathologic material has not been staged uniformly according to accepted criteria. Thus the various series are not comparable. Comparisons between series require standardization with respect to stage of disease, pathologic classification, and treatment protocols. Before any modification of the standard pancreaticoduodenectomy is adopted, an appropriately designed study should be performed to test its efficacy. This study would also require a more comprehensive analysis of the pathologic material than is commonly performed today in the United States and Europe.     

Five-year survival rates of melanoma patients treated by diet therapy after the manner of Gerson: a retrospective review

OBJECTIVE: Compare 5-year melanoma survival rates to rates in medical literature. DESIGN: Retrospective. SETTING: Hospital in Tijuana, Mexico. PATIENTS: White adult patients (N = 153) with superficial spreading and nodular melanoma, aged 25-72 years. INTERVENTION: Gerson's diet therapy: lactovegetarian; low sodium, fat and (temporarily) protein; high potassium, fluid, and nutrients (hourly raw vegetable/fruit juices). Metabolism increased by thyroid; calorie supply limited to 2600-3200 calories per day. Coffee enemas as needed for pain and appetite. MAIN OUTCOME MEASURE: 5-year survival rates by stage at admission. RESULTS: Of 14 patients with stages I and II (localized) melanoma, 100% survived for 5 years, compared with 79% of 15,798 reported by Balch. Of 17 with stage IIIA (regionally metastasized) melanoma, 82% were alive at 5 years, in contrast to 39% of 103 from Fachklinik Hornheide. Of 33 with combined stages IIIA + IIIB (regionally metastasized) melanoma, 70% lived 5 years, compared with 41% of 134 from Fachklinik Hornheide. We propose a new stage division: IVA (distant lymph, skin, and subcutaneous tissue metastases), and IVB (visceral metastases). Of 18 with stage IVA melanoma, 39% were alive at 5 years, compared with only 6% of 194 from the Eastern Cooperative Oncology Group. Survival impact was not assessed for stage IVB. Male and female survival rates were identical for stages I-IIIB, but stage IVA women had a strong survival advantage. CONCLUSIONS: The 5-year survival rates reported here are considerably higher than those reported elsewhere. Stage IIIA/B males had exceptionally high survival rates compared with those reported by other centers.