Phylogeography of the false smooth snakes, Macroprotodon (Serpentes, Colubridae): mitochondrial DNA sequences show European populations arrived recently from Northwest Africa

Mitochondrial DNA (1075 bp: cytochrome b, 300 bp; 12S rRNA, 393 bp; and 16S rRNA, 382 bp) corroborates the monophyly of the genus Macroprotodon and of the species M. mauritanicus, M. abubakeri, and M. brevis. The subspecies M. brevis ibericus is also monophyletic. The mtDNA tree presented here indicates that M. cucullatus consists of at least two separate units and may possibly represent a primitive morphology rather than a species in its own right. However, this hypothesis is tentative since it is only reflects the history of a single evolutionary unit (mtDNA). A definitive understanding of the evolution of M. cucullatus will not be possible until informative nuclear markers are added to the mitochondrial data. Macroprotodon appears to have originated in the Maghreb region of NW Africa and speciated there around 4-5.5 million years ago around the end of the Miocene period, after which its three main lineages may each have expanded north into more mesic conditions. The group also spread eastwards into coastal areas of Libya quite recently and on to Egypt and Israel. Later still, M. b. ibericus from extreme north Morocco reached the Iberian Peninsula, and M. mauritanicus from Tunisia or Algeria colonised the Balearic Islands of Menorca and Mallorca. Both these range extensions may result from very recent natural colonisations or even from accidental human introduction. Recency of origin of Iberian and Balearic populations is indicated by uniformity of their mtDNA even across large distances, and its great similarity to that of populations in source regions. Isolated populations assigned to M. cucullatus in the Hoggar mountains (southern Algeria) and Western Sahara are probably relicts from quite recent periods of climatic amelioration in the North African desert.

Penetration of intravenous moxalactam into human aqueous humor

Intraocular penetration of moxalactam disodium, a new broad-spectrum oxa-beta-lactam antibiotic, was studied in 18 patients undergoing cataract surgery. The antibiotic was administered in a 2-g single dose by intravenous drip during a 20-minute period. After 40 to 230 minutes, moxalactam aqueous humor concentrations ranged from 1.1 to 5.0 micrograms/mL (mean, 2.3 micrograms/mL). The ratio of aqueous humor concentrations to concomitant serum concentrations ranged from 1.6% to 9.8%. The achievable aqueous moxalactam concentrations were well above the minimum inhibitory concentrations of most Gram-negative enteric bacilli but not of Pseudomonas and staphylococci.

Intraocular penetration of sisomicin in rabbits

The intraocular penetration of sisomicin, an aminoglycoside antibiotic, was studied in 47 normal rabbits following subconjunctival and/or intramuscular (IM) injections. Sisomicin levels were determined in the cornea and the aqueous humor of the injected eye as well as in the aqueous of the fellow eye by means of the cylinder-plate bioassay technique. When the IM route alone was used, the eye tissue concentrations remained negligible. One hour after subconjunctival injection, highly therapeutic sisomicin concentrations were achieved in the aqueous humor of both injected and fellow eyes, but the level dropped to very low concentrations 12 hours after the injection. The concomitant administration of sisomicin intramuscularly and subconjunctivally resulted in a significant delay of the clearance of sisomicin from the eye tissues. The use of the combined subconjunctival-IM regimen for administering aminoglycoside antibiotics needs further evaluation.