Diagnostic implications of neuroimaging in epilepsy and other seizure disorders.

Epilepsy is the most common neurological disorder that affects ~1-2% of the global population, leading to presentation in the emergency room. The neuroimaging modalities have an important application in diagnosing new onset unprovoked seizures and epilepsy. This article discusses the various neuroimaging modalities for diagnosing seizures and epilepsy and addresses that the MRI is the investigation of choice, and urgent imaging is more commonly done by computed tomography in patients with new-onset seizures. The goal of the article was to diagnose seizures and epilepsy for early intervention to prevent complications or damage to the brain. MRI detects even small cortical epileptogenic lesions, whereas computed tomography is used in screening, diagnosis, evaluation, and monitoring of the prognosis of seizures in children. Magnetic resonance spectroscopy provides biochemical measurements of reduced N-acetyl aspartate and increased creatinine and choline in dysfunctioning epileptic zones. Volumetric MRI is very sensitive and specific in determining seizures originating in extratemporal and extrahippocampal sites. Even though diffusion tensor magnetic resonance imaging has a limited role, it is used in specific pediatric patient groups with temporal lobe epilepsy. Functional radionuclide imaging modalities (positron emission tomography and single-photon emission computerized tomography) are increasingly significant for the identification of the epileptic region. Furthermore, the authors recommend the use of artificial intelligence and further research on imaging modalities for early diagnosis of seizures and epilepsy.

A broad-spectrum microbicide with virucidal activity against sexually transmitted viruses.

Sodium dodecyl sulfate (SDS), an alkyl sulfate surfactant derived from an organic alcohol, possesses surfactant properties but also denatures and unfolds both monomeric and subunit proteins. In preliminary experiments, we demonstrated that SDS is a potent inactivator of herpes simplex virus type 2 and human immunodeficiency virus type 1 at concentrations comparable to those used for the surfactant nonoxynol-9. We hypothesized that SDS might be capable of denaturing the capsid proteins of nonenveloped viruses. In this report, we demonstrate inactivation of rabbit, bovine, and human papillomaviruses after brief treatment with dilute solutions of SDS. Effective concentrations were nontoxic to rabbit skin and to split-thickness grafts of human foreskin epithelium. This is the first report of a microbicidal surfactant that will inactivate papillomaviruses. We propose that SDS is now a candidate microbicide for formulation and testing with humans.

Coinfection of human foreskin fragments with multiple human papillomavirus types (HPV-11, -40, and -LVX82/MM7) produces regionally separate HPV infections within the same athymic mouse xenograft.

The athymic mouse xenograft system was used to prepare infectious stocks of two additional anogenital tissue-targeting human papillomaviruses (HPVs) in a manner similar to that for the development of infectious stocks of HPV-11. An anal condyloma from a transplant patient was used as material for extraction of infectious virus, and human foreskin fragments were incubated with the virus suspension and transplanted subrenally into athymic mice. Partial viral sequencing indicated that two rare HPV types (HPV-40 and HPVLVX82/MM7) were concurrently present in both the patient condyloma and the foreskin xenografts, and passage of both types was achieved as a mixed infection with HPV-40 predominating. Xenografts that developed from simultaneous infection of human foreskin fragments with HPV-11, -40, and -LVX82/MM7 virions produced regionally separate areas of HPV-11 and -40 infection as determined by in situ hybridization. In addition, in situ hybridization with HPV-40 and HPVLVX82/MM7 DNA probes demonstrated that both of these HPV types were present as adjacent but separate infections within the same anal condyloma of the transplant patient. These studies indicate that multiple HPV types can simultaneously infect genital tissue and that each HPV type predominantly maintains regional separation within the same papilloma.

Laboratory production of infectious stocks of rabbit oral papillomavirus.

Several small, raised lesions from the underside of the tongue of domestic rabbits were isolated, and an extract prepared and tested for the presence of rabbit oral papillomavirus (ROPV). Two weeks after inoculation of this extract into the underside of rabbit tongues, multiple small discrete, grey-white nodules were observed that reached a maximum size of 2 mm in diameter by 5 weeks. These lesions showed typical ROPV pathology, and nuclei stained positive for papillomavirus (PV) group-specific antigen (GSA) by immunocytochemistry. Tissue fragments from rabbit tongues were incubated with a suspension of ROPV and placed subrenally into athymic mice. After 60 days, cysts were removed, sections cut for histology, and a virus stock prepared. GSA staining and in situ hybridization demonstrated that the xenografts were morphologically transformed with areas showing strong nuclear staining for viral capsid antigen and ROPV DNA. Extracts prepared from the pooled xenografts contained infectious ROPV as demonstrated by inoculation into the undersurface of tongues of nonimmune New Zealand White rabbits. The results demonstrated that stocks of infectious ROPV can be prepared in the athymic mouse xenograft system for use in studies on the experimental transmission of a mucosal-targeting animal papillomavirus.

High efficiency induction of papillomas in vivo using recombinant cottontail rabbit papillomavirus DNA.

Plasmids containing cottontail rabbit papillomavirus (CRPV) DNA can induce papillomas in vivo, but efficiency has been low. The aim of the present investigation was to explore some of the technical variables involved in inoculation of rabbits with recombinant CRPV DNA in attempts to improve both yield and consistency of papilloma induction. It was found that induction of epidermal hyperplasia, with either a mixture of turpentine and acetone or phorbol esters, produced a marked increase in papilloma yield. An additional powerful factor was the use of very vigorous, cutaneous scarification, sufficient to penetrate the papillary dermis and produce bleeding. When used in combination, papilloma yields were consistent and often reached 90-100% of inoculated sites. A number of other variables which did not consistently affect papilloma yield were tested. These included bleb and puncture injections, plasmid dose, vector type, occlusive dressings, lipofection reagent, carrier DNA, and different methods for plasmid DNA extraction and purification. It is concluded that the most important variables in improving papilloma yields were prior induction of epidermal hyperplasia and vigorous cutaneous scarification.

Assembled baculovirus-expressed human papillomavirus type 11 L1 capsid protein virus-like particles are recognized by neutralizing monoclonal antibodies and induce high titres of neutralizing antibodies.

Baculovirus-expressed human papillomavirus type 11 (HPV-11) major capsid protein (L1) virus-like particles (VLPs) were produced in insect cells and purified on CsCl density gradients. The VLPs retained conformational neutralizing epitopes that were detected by a series of HPV-11-neutralizing monoclonal antibodies. Electron microscopy determined that the HPV-11 L1 VLPs were variable in size with a surface topography similar to that of infectious HPV-11. The VLPs were very antigenic, and induced high titres of neutralizing antibodies in rabbits and mice when used as an immunogen without commercial preparations of adjuvant. These VLP reagents may be effective vaccines for protection against HPV infections.

Monoclonal antibody-mediated neutralization of infectious human papillomavirus type 11.

Monoclonal antibodies recognizing human papillomavirus type 11 (HPV-11) were prepared from BALB/c mice immunized with intact HPV-11 virions obtained from morphologically transformed human foreskin xenografts grown subrenally in athymic mice. Four of five monoclonal antibodies that were reactive by enzyme-linked immunosorbent assay only to intact virions neutralized HPV-11 infectivity in the athymic mouse xenograft system.

Experimental infection with human papillomavirus type 1 of human hand and foot skin.

Warts of the hands and feet are common cutaneous diseases. Human papillomaviruses types 1 and 2 are probably responsible for most of the lesions. It is difficult to study these infections in the laboratory, since human papillomaviruses do not replicate in cell cultures or experimental animals. We have recently developed a system in which xenografts of human tissues were infected with HPV-11 and transplanted beneath the renal capsule of athymic mice. We now report the adaptation of this system to the induction of HPV-1 infection of xenografts of fetal human foot and hand skin. The experimentally produced warts have the same morphology as naturally occurring lesions. HPV-1 DNA and papillomavirus capsid antigen are abundant in the experimentally infected tissues.

Vitamin K1 reduction in human liver. Location of the coumarin-drug-insensitive enzyme.

The antidotal effect of vitamin K in overcoming poisoning by coumarin anticoagulant drugs is mediated by a vitamin K-reducing enzyme of the endoplasmic reticulum [Wallin & Martin (1987) Biochem. J. 241, 389-396]. With microsomes obtained from human liver biopsies, we have investigated the localization and the transverse orientation of this enzyme in the endoplasmic reticulum and compared its orientation to that of the other enzymes of the vitamin K-dependent carboxylation system. All enzymes were protected by the microsomal membrane and thus appear to have a luminal orientation in the endoplasmic reticulum, consistent with their role in the vitamin K-dependent modification of secretory glycoproteins. Separation of rough and smooth microsomes showed that vitamin K-dependent carboxylase activity was 6-fold higher in rough than in smooth microsomes. Vitamin K1 reduction by the coumarin-drug-sensitive (pathway I) and -insensitive (pathway II) enzymes of the vitamin K-dependent carboxylation system was the same in rough and smooth microsomes. The data suggest a close association between the pathway I and II enzymes in the endoplasmic reticulum. These pathways may be partial reactions of multienzyme complex which carries out the various activities associated with the vitamin K-dependent carboxylation system.

3-Methylcholanthrene induction of enzymes in the vitamin K-dependent carboxylation system.

The effect of 3-methylcholanthrene on liver enzymes in the vitamin K-dependent carboxylation system has been investigated in normal rats and rats treated with the anticoagulant warfarin. It was found that 3-methylcholanthrene did not interfere with the anticoagulant function of the drug. Treatment of rats with 3-methylcholanthrene resulted in a 2.7-fold increase in liver cytosolic DT-diaphorase activity and a 1.5-fold increase in liver microsomal vitamin K-dependent carboxylase activity. A pathway for production of reduced vitamin K cofactor for the vitamin K-dependent carboxylase is catalyzed by DT-diaphorase and an as yet unidentified NADH-specific dehydrogenase(s). The data suggest that the unidentified enzyme(s) in the pathway is not induced by 3-methylcholanthrene.

DT-diaphorase in morbidly obese patients.

Dicumarol sensitive DT-diaphorase (EC 1.6.99.2) activity has been measured in human cytosol from liver and various extrahepatic tissues not containing tumors which were removed during elective operations. The specific activity was found to be highest in tissues of the gastrointestinal tract. In contrast to rodent liver, the human liver has extremely low DT-diaphorase activity. Tissue activity was found to be highly variable among the patients studied which suggests that nutritional and/or genetic factors may be involved. The variability ranged from undetectable levels in liver to 223 nmol/mg X min in stomach. The data question whether the current concept concerning the biological function of this enzyme is applicable to man.

Rat and human liver vitamin K epoxide reductase: inhibition by thiol blockers and vitamin K1.

1. Reduction of vitamin K1 2,3-epoxide by rat and human liver vitamin K epoxide reductase is inhibited by N-ethylmaleimide and iodoacetamide. 2. Both enzymes are protected from inhibition by N-ethylmaleimide by vitamin K1 or vitamin K1 2,3-epoxide. 3. Vitamin K1 inhibits reduction of vitamin K1 2,3-epoxide to vitamin K1 which suggests product inhibition of the enzyme.

Vitamin K antagonism of coumarin intoxication in the rat.

An in vitro system which expresses all enzyme activities related to vitamin K-dependent carboxylation of blood clotting factors was prepared from livers of rats overdosed with warfarin, difenacoum and dicumarol respectively. In this system, the activities of the two pathways that are known to produce active reduced vitamin K1 cofactor for the carboxylation reaction were measured. Also the ability of high concentrations of vitamin K1 to overcome inhibition of clotting factor synthesis was studied. In the systems prepared from livers of warfarin and difenacoum intoxicated rats, pathway I was inactive. Vitamin K epoxide reductase was also inactive which strongly suggests that this enzyme catalyzes the activity of pathway I in vivo. Reduction of vitamin K1 by pathway II bypassed the inactive pathway I and resulted in carboxylation activity. This pathway therefore mediates the antidotic effect of vitamin K1 in the coumarin intoxicated liver. In the in vitro system prepared from dicumarol intoxicated livers the activity of pathway I was not significantly affected. Dicumarol however was a strong inhibitor when added to liver microsomes in vitro.