Pharmaceutical applications for molecularly imprinted polymers.

Molecular imprinting is a means of introducing sites of specific molecular arrangement into an otherwise uniform polymeric matrix. This is achieved by formation of a pre-polymerisation complex between complementary monomers and the template molecule. Subsequent polymerisation in the presence of a crosslinker, in a porogenic environment, results in the production of a macroporous polymer capable of specific molecular recognition. This paper considers potential roles for molecularly imprinted polymers within a pharmaceutical remit. Applications including controlled release, drug monitoring devices and biological receptor mimetics are discussed. Histamine and ephedrine molecularly imprinted polymers (MIPs) were studied as potential biological receptor mimics whilst a propranolol MIP was investigated for its use as a rate attenuating selective excipient in a transdermal controlled release device. Preliminary studies concerning the preparation of a theophylline selective transcutaneous monitoring device, using a theophylline MIP, are also described.

The expression of aphidicolin-induced fragile sites in familial breast cancer patients.

The expression frequency of aphidicolin-induced fragile sites was examined in familial breast cancer patients to determine whether this parameter could be used as a marker of genetic susceptibility in at-risk individuals. No difference was found in expression frequency between the breast cancer patients and a group of normal individuals (p = 0.61). This indicates that the expression frequency of aphidicolin-induced fragile sites is not a suitable marker for assessing genetic susceptibility in familial breast cancer.

Radiographic evaluation of intraosseous implants of endodontic materials.

Following several case reports of cyst development after endodontic treatment of decidous teeth, the osseous response to formaldehyde- or phenol-based materials was evaluated by a standardized radiographic technique. Endodontic medicaments contained in Teflon carriers were implanted between feline deciduous canine and molar teeth and the permanent successional teeth. Persistent radiolucency surrounding formocresol implants and sequestration of Kri-paste implants were noted in contrast to apparent bony healing around the zinc oxide-eugenol controls and those implants containing glutaraldehyde. These results suggest a greater tissue tolerance to glutaraldehyde-containing agents in contrast to the more traditional endodontic agents used in deciduous teeth.

Reversal of clonidine-induced hypotension by beta-adrenoceptor blocking drugs.

The interaction between clonidine, propranolol and sotalol was investigated using conscious normotensive and spontaneously hypertensive rabbits as well as conscious normotensive and spontaneously hypertensive rats. Clonidine (20 micrograms/kg) administration into the marginal ear vein of rabbits produced persistent hypotension and bradycardia. In propranolol (0.5 mg/kg, i.v.)-pretreated animals, clonidine-induced hypotension was prevented. In rats, daily oral or subcutaneous clonidine as well as propranolol produced hypotension and bradycardia. Significant antagonism of the observed hypotensive effects resulted when clonidine was given to propranolol-pretreated animals or when propranolol was added to the treatment regimen of animals being maintained on clonidine. No antagonism between sotalol and clonidine was demonstrable. In view of the known central site of action of clonidine, and the failure of sotalol to antagonize clonidine-induced hypotension it would appear that the central nervous system is a possible site of the observed drug interaction.

Sex-limited and sex-modified genetic defects in swine--cryptorchidism.

Review of published data suggests that cryptorchidism in Chester Whites and Yorkshires is caused by completely penetrant, recessive genes at two autosomal loci; in Lacombes, multifactorial modes of inheritance are more plausible. Different genetic systems control presence of the trait vs. number of sides affected; left testes are retained more often in almost all samples. Contrary to previous claims prenatal viability of homozygous males and females is normal. Genes causing cryptorchidism are unlikely to affect many other malformations in either sex, but pleiotropy is suggested to extend to economic traits such as conformation in females.