Blood digestion in the mosquito, Anopheles stephensi: the effects of Plasmodium yoelii nigeriensis on midgut enzyme activities

Midgut proteases contribute to the success or failure of Plasmodium infection of the mosquito. This paper examines the reciprocal effect of Plasmodium yoelii nigeriensis on midgut trypsin, chymotrypsin, aminopeptidase and carboxypeptidase in the mosquito Anopheles stephensi. The total protein ingested and the rate of protein digestion were unaffected by the parasite, but more protein was ingested at the first than the second bloodmeal. All peptidases were unaffected by the presence of the parasite during the first gonotrophic cycle, when ookinetes were penetrating the midgut. In the second gonotrophic cycle, trypsin and chymotrypsin were unaffected by growing oocysts, but aminopeptidase activity was reduced in the midguts of infected mosquitoes. Chymotrypsin activity was depressed and aminopeptidase activity elevated during the second gonotrophic cycle. Plasmodium infection has a negligible effect on bloodmeal digestion and does not limit the availability of the protein for egg production. The significance of changes in aminopeptidase activity when oocysts are present is discussed.

A modified irrigating-aspirating needle

To facilitate the safe and thorough evacuation of cortical lens debris in extracapsular extractions the author has modified the coaxial irrigating-aspirating cannula. The modified needle has a 45 degrees bend 10 mm from its tip. The tip is rendered slightly bulbous, thus eliminating the step between the outer sleeve and the coaxial portion. This prevents snagging of the posterior capsule and eliminates sleeve slide. The needle has been found especially helpful in deeply recessed eyes, and, when it was rotated, cortical cleaning from the equatorial and superior portions of the capsular bag was easier than with a straight needle. There were no posterior capsular breakages in 54 consecutive cases of the use of this needle.

Paralytic strabismus correction by adjustable suture technique

The surgical correction of four cases of paralytic strabismus, in which the muscle is repositioned postoperatively with the active co-operation of the patient, is described. The method adopted by the author, by inserting the suture near the limbus, increases the degree of adjustability and allows for more extensive repositioning of the conjunctiva.

A cannulated probe for torn inferior canaliculus repair

A cannulated probe and silicone tube for the repair of the torn inferior canaliculus are described and illustrated.

Acute endocrine exophthalmos

A case is reported of acute endocrine exophthalmos in a 60-year-old clinically euthyroid male diabetic and the rapid response to steroid therapy is described. The exophthalmometer was used to assess objectively the variations of the exophthalmos.