Oral non-squamous malignant tumors; diagnosis and treatment

Some 90% of oral cancers consist of squamous cell carcinomas that arise from the oral mucosa. The remaining 10% of malignancies consist of malignant melanomas, carcinomas of the intraoral salivary glands, sarcomas of the soft tissues and the bones, malignant odontogenic tumors, non-Hodgkin?s lymphomas and metastases from primary tumors located elsewhere in the body. These malignancies will be briefly reviewed and discussed. The emphasis is on diagnosis and management

Mass transfer in corrugated-plate membrane modules. I. Hyperfiltration experiments

The application of corrugations as turbulence promoters in membrane filtration was studied. This study showed that it is possible to deform an originally flat membrane to a corrugated shape without damaging it. In hyperfiltration experiments using corrugated cellulose acetate membranes it was found that the corrugations improve mass transfer, provided they are not too close together. At a given value of the mass-transfer coefficient, the presence of corrugations can lead to lower energy consumption in hyperfiltration than possible with flat membranes

Mass transfer in corrugated-plate membrane modules. II. Ultrafiltration experiments

The application of corrugations as turbulence promoters in membrane filtration was studied. In ultrafiltration experiments with polysulfone membranes using Dextran T70 as solute, it was found that the corrugations result in reduced energy consumption or pressure drop compared with flat membranes at a given value of the flux through the membrane. There appears to be an optimal mutual distance between the corrugations

Oral leukoplakia, the ongoing discussion on definition and terminology

In the past decades several definitions of oral leukoplakia have been proposed, the last one, being authorized by the World Health Organization (WHO), dating from 2005. In the present treatise an adjustment of that definition and the 1978 WHO definition is suggested, being : “A predominantly white patch or plaque that cannot be characterized clinically or pathologically as any other disorder; oral leukoplakia carries an increased risk of cancer development either in or close to the area of the leukoplakia or elsewhere in the oral cavity or the head-and-neck region”. Furthermore, the use of strict diagnostic criteria is recommended for predominantly white lesions for which a causative factor has been identified, e.g. smokers’ lesion, frictional lesion and dental restoration associated lesion. A final diagnosis of such leukoplakic lesions can only be made in retrospect after successful elimination of the causative factor within a somewhat arbitrarily chosen period of 4-8 weeks. It seems questionable to exclude “frictional keratosis” and “alveolar ridge keratosis” from the category of leukoplakia as has been suggested in the literature. Finally, brief attention has been paid to some histopathological issues that may cause confusion in establishing a final diagnosis of leukoplakia

Are we able to reduce the mortality and morbidity of oral cancer: some considerations

Oral cancer makes up 1%-2% of all cancers that may arise in the body. The majority of oral cancers consists of squamous cell carcinomas. Oral cancer carries a considerable mortality rate, being mainly dependent on the stage of the disease at admission. Worldwide some 50% of the patients with oral cancer present with advanced disease. There are several ways of trying to diagnose oral cancer in a lower tumor stage, being 1) mass screening or screening in selected patients, 2) reduction of patients' delay, and 3) reduction of doctors' delay. Oral cancer population-based screening ('mass screening') programs do not meet the guidelines for a successful outcome. There may be some benefit when focusing on high-risk groups, such as heavy smokers and heavy drinkers. Reported reasons for patients' delay range from fear of a diagnosis of cancer, limited accessibility of primary health care, to unawareness of the possibility of malignant oral diseases. Apparently, information campaigns in news programs and TV have little effect on patients' delay. Mouth self-examination may have some value in reducing patients' delay. Doctors' delay includes dentists' delay and diagnostic delay caused by other medical and dental health care professionals. Doctors' delay may vary from almost zero days up to more than six months. Usually, morbidity of cancer treatment is measured by quality of life (QoL) questionnaires. In the past decades this topic has drawn a lot of attention worldwide. It is a challenge to decrease the morbidity that is associated with the various treatment modalities that are used in oral cancer without substantially compromising the survival rate. Smoking cessation contributes to reducing the risk of oral cancers, with a 50% reduction in risk within five years. Indeed, risk factor reduction seems to be the most effective tool in an attempt to decrease the morbidity and mortality of oral cancer