[Clinical studies using the combination atovaquone-proguanil as malaria prophylaxis in non-immune adult and child travelers]

Prophylaxis for short-term travel in malaria-endemic areas can be difficult for two reasons. The first is that currently available antimalarial drugs are becoming less effective because of the ability of the parasite to adapt to drug pressure. The second involves poor compliance with chemoprophylactic regimens due to the highly restrictive conditions of administration and adverse drug side-effects, especially in "healthy" subjects. The combination of atovaquone/proguanil (Malarone) could provide an answer to both these problems since it is not only effective on multiresistant strains of Plasmodium falciparum but also simplifies the conditions of administration and shows good tolerance in adults and children.

[Role of plasminogen activator inhibitor type 1 in tumor angiogenesis]

The plasminogen/plasmin system plays a key role in cancer progression, presumably via mediating extracellular matrix degradation and tumour cell migration. High levels of components of the plasminogen activation system, and paradoxically also its inhibitor, plasminogen activator inhibitor 1 (PAI-1), have been correlated with a poor prognosis for patients with cancers of different types. Recent findings clearly suggest that PAI-1 is essential for capillary sprouting during tumour angiogenesis. Moreover, there is accumulating evidence that both the urokinase receptor and PAI-1 are multifunctional proteins involved not only in extracellular matrix proteolysis but also in cellular adhesion and migration through their binding site for vitronectin. The understanding of whether PAI-1 plays a regulatory role in angiogenesis by tightly controlling proteolytic activity or by influencing cell migration could allow a new anti-angiogenic approach for tumour therapy.

New functions of stromal proteases and their inhibitors in tumor progression

Acquisition of invasive metastatic potential through protease expression is a key event in tumor progression. In carcinomas, the production of metalloproteinases and serine proteinases is regulated by a cross talk between stromal cells and cancer cells. Paradoxically, high rather than low levels of their inhibitors predict poor survival of patients suffering from a variety of cancers. Recent observations suggest a much more complex role of these inhibitors in tumor progression than expected initially.

The ability of preoperative serum CA-125 to predict optimal primary tumor cytoreduction in stage III epithelial ovarian carcinoma

PURPOSE

The aim of this study was to determine the ability of preoperative serum CA-125 to predict optimal primary tumor cytoreduction in patients with Stage III epithelial ovarian carcinoma.

METHODS

We performed a retrospective chart review of 100 consecutive patients with Stage III ovarian carcinoma who had a serum CA-125 drawn prior to primary cytoreductive surgery. We used a receiver operating characteristic curve to determine the CA-125 level with the maximal prognostic power in predicting optimal versus suboptimal cytoreduction.

RESULTS

The median CA-125 level for the 100 patients was 819 U/ml (range 5.6-26,200 U/ml). Optimal cytoreduction (diameter of largest residual tumor nodule < or =1 cm) was obtained in 45 cases (45%). The probability of performing optimal cytoreduction decreased with increasing CA-125 levels. A preoperative CA-125 level of 500 U/ml was identified as the value with the most predictive power. Optimal cytoreduction was achieved in 33 of the 45 cases (73%) with a CA-125 less than 500 U/ml compared to only 12 of the 55 cases (22%) with a CA-125 greater than 500 U/ml. Using a threshold level of 500 U/ml, the preoperative serum CA-125 level was able to predict optimal versus suboptimal cytoreduction with a sensitivity of 78%, specificity of 73%, positive predictive value of 78%, and negative predictive value of 73%.

CONCLUSION

The probability of performing optimal cytoreduction in patients with Stage III ovarian carcinoma and a preoperative CA-125 greater than 500 U/ml was approximately one in five. These patients may be candidates for initial laparoscopic evaluation to obtain a confirmatory tissue diagnosis and to determine resectability.

Absence of host plasminogen activator inhibitor 1 prevents cancer invasion and vascularization

Acquisition of invasive/metastatic potential through protease expression is an essential event in tumor progression. High levels of components of the plasminogen activation system, including urokinase, but paradoxically also its inhibitor, plasminogen activator inhibitor 1 (PAI1), have been correlated with a poor prognosis for some cancers. We report here that deficient PAI1 expression in host mice prevented local invasion and tumor vascularization of transplanted malignant keratinocytes. When this PAI1 deficiency was circumvented by intravenous injection of a replication-defective adenoviral vector expressing human PAI1, invasion and associated angiogenesis were restored. This experimental evidence demonstrates that host-produced PAI is essential for cancer cell invasion and angiogenesis.

Bodies of knowledge

I learned the hard way, the old-fashioned way. I did my first pelvic exam on a colleague, who then did her first on me. We were terrified amateurs, willing to endure all just to get through. "You did great!" we congratulated each other, masking the inevitable discomfort with hearty words of encouragement. I did my second pelvic exam on a patient. What that patient experienced, I'll never know, because she didn't tell and I didn't ask. It took a year or two for me to begin to feel comfortable with the procedure and more years to feel skilled at it. And still I couldn't gauge my patient's experience. I'd say, casually, "You okay?" as I inserted the speculum. She'd say "Uh huh." Sometimes she convinced me, sometimes not.

Art of the paradigm shift

How long has it been since you've had a good paradigm shift? No, it's nothing you can plan. Nothing you can simply tick off that perennial list of To Do's tucked away in your pocket or some unoccupied sulcus of your brain. Paradigm shifts simply happen when you are on a journey of discovery. Once they happen, they change forever the way you look at the world.

Influence of sterilization processes on poly(epsilon-caprolactone) nanospheres

Polymeric vectors and especially poly(epsilon-caprolactone) nanoparticles have already shown promising results in the optimization of the ophthalmic bioavailability of drugs. Any formulation instilled in the eye must be sterile, and preferentially isotonic. Poly(epsilon-caprolactone) nanospheres were thus formulated with Synperonic PE/F68, Synperonic PE/F127, or Cremophor RH40. A tonicity agent, a preservative and, in some cases, a viscosifiant were then added. The pH was finally adjusted to pH 4 or buffered to pH 7. Different sterilization processes were studied to investigate their influence on the physicochemical characteristics of vectors. Autoclaving did not induce any modification on polymer molecular weight or Synperonic nanospheres diameter, but catalysed some reactions with surfactants and tonicity agents. This method could thus be used if the nanosphere excipients are chosen with care. gamma radiation induced preservative degradation and viscosifiant depolymerization. A cross-linking of poly(epsilon-caprolactone) chains was observed, as reflected by a sharp increase of its molecular weight. However, no variation of the mean particle size was detected. Finally, sterile filtration was the only process which ensured the conservation of physicochemical integrity of nanospheres. This process was successfully applied on non-viscosified vectors with a sufficiently small diameter.