Discrimination Between Paraffin-Embedded and Frozen Skin Sections Using Synchrotron Infrared Microspectroscopy

The difference between paraffin-embedded and frozen skin sections is always questionable. Ten patients of early stage mycosis fungoides, ten patients with psoriasis and ten normal controls were included in this study. Aim of this study is to differentiate between paraffin-embedded and frozen skin sections in inflammatory and malignant dermatoses using synchrotron infrared microspectroscopy (SIRM). It was found that epidermal beta sheets in paraffin-embedded sections were higher in a highly significant manner than frozen sections (P < 0.001). Also, epidermal nucleic acids in paraffin-embedded sections were lower in a highly significant manner than frozen sections (P < 0.001). However, when various skin diseases were compared with the control. It was found that the difference between paraffin-embedded and frozen skin sections were almost similar. In conclusion SIRM is a unique promising diagnostic technique and it seems that frozen processing preserve skin tissue more, this was represented by less apoptosis (beta sheets) and more nucleic acids than paraffin processing. However, there are still many advantages of both approaches over the other depending on the goal of the study.     

Impact of pyrethroid-impregnated curtains on Phlebotomus papatasi sandflies indoors at Khartoum, Sudan

Laboratory and field investigations were made in an endemic focus of cutaneous leishmaniasis in Khartoum State, Sudan, to evaluate the effects of permethrin-impregnated curtains on the human-biting activity, nocturnal activity and resting behaviour of the vector sandfly Phlebotomus papatasi (Diptera: Psychodidae) indoors. Laboratory bioassays showed that curtains impregnated with 0.5, 1.0 or 1.5 g/m2 permethrin all gave 100% mortality within 24h of exposure of P. papatasi for 3 min. Under natural field conditions, the biting activity indoors and the resting density of P. papatasi were significantly reduced (P<0.001 and P=0.036, respectively) in rooms provided with permethrin-impregnated curtains as compared to control rooms left without curtains or fitted with unimpregnated curtains. No significant difference was found between the numbers of nocturnally active P. papatasi collected in rooms provided with impregnated curtains and rooms left without curtains or provided with unimpregnated curtains (P=0.377). Evidently P. papatasi was not repelled by these doses of permethrin on curtains, but the survival rate of sandflies collected from test rooms provided with permethrin-impregnated curtains was significantly reduced (P=0.036). We conclude that use of permethrin-impregnated curtains may provide a good control method for P. papatasi and other endophilic and/or endophagic sandfly vectors of leishmaniasis.     

Cellulolytic bacteria as primary colonizers ofPotamogeton pectinatus L. (Sago Pond Weed) from a Brackish South-Temperate Coastal Lake

Bacteria adhering to newly emerged and decomposing leaves ofPotamogeton pectinatus L. were examined using scanning electron microscopy. Bacteria obtained from mature leaves were isolated, grown in pure culture, and allowed to infect bacteria-free leaves. Infected leaves and individual isolates were examined by scanning electron microscopy. The method provided detail of the forms of bacterial attachment to leaf surfaces.Supernatants from isolate cultures were assayed for cellulase activity. Six out of eight isolates produced extracellular cellulase in medium containing carboxymethyl cellulose. In one isolate cellulase was produced at discrete intervals, at the beginning and end of the growth cycle. The adhesion of the isolates toP. pectinatus leaves, as well as their possession of cellulase, are considered as evidence of an active role of bacteria in the degradation ofP. pectinatus foliage. The system is unusual in that bacteria, as opposed to fungi, are primary colonizers of the leaves.