Transepithelial paracellular leakiness induced by chronic phorbol ester exposure correlates with polyp-like foci and redistribution of protein kinase C-alpha

Although exposure of LLC-PK1 epithelial cell sheets to phorbol esters (TPA) causes a near immediate and total decrease of transepithelial electrical resistance (TER), continuation of exposure for 3 to 4 days results in a tachyphylactic response as TER begins to return to control levels. Recovery of TER is maximal by 5 to 6 days, but reaches only 70 to 80% of control level. A reciprocal change in the transepithelial flux of D-mannitol indicates that the TER decrease is indicative of an increase in tight junction permeability. Exposure of cell sheets to TPA for several days also results in the appearance of multilayered polyp- like foci (PLFs) across the otherwise one cell layer thick cell sheets. The pattern of penetration of the electron dense dye, ruthenium red, from the apical surface, across the tight junction and into the lateral intercellular space indicates that the tight junctions of the cell sheet become uniformly leaky after acute exposure to TPA. However, when exposure is continued for several days, only the junctions of cells in the PLFs manifest leakiness. The decrease in TER following acute TPA exposure correlates with the translocation of protein kinase C-alpha (PKC alpha) into a membrane-associated compartment. With exposure of several days, only a trace of PKC alpha is visible by Western immunoblot, and this is in the membrane-associated compartment. Immunofluorescent microscopy indicates that the trace of PKC alpha seen in the Western immunoblots is ascribable distinctly to cells of the PLFs. Monolayer areas between PLFs show no discernible immunofluorescent signal. The data therefore indicate that tight junction barrier function may be restored in certain areas by the down regulation of PKC alpha from the membrane-associated compartment. Failure to down regulate may result in the paracellular leakiness and abnormal cell architecture of the PLFs. Possible implications of this model for in vivo epithelial tumor promotion are discussed.      

Molecular analysis of PKU in Ireland

Classical phenylketonuria (PKU: McKusick No. 261600) is caused by mutations occurring at the phenylalanine hydroxylase (PAH) locus on chromosome 12 and has a prevalence in Ireland of 1 in 4500. We examined 304 independent alleles from 350 patients for the presence of six mutations and have characterized VNTR alleles within the minisatellite region 3' to the PAH gene in patients carrying the most prevalent mutation. R408W was the most common mutation found, with a relative frequency of 42%. All other mutations had relative frequencies of <10%. VNTR analysis showed that the R408W mutation is associated with the VNTR-8 allele in the Irish population, indicating that R408W is associated with RFLP haplotype 1. This differs from that reported from eastern Europe where R408W is associated with RFLP haplotype 2/VNTR-3; an observation which has led several groups to propose a Balto-Slavic origin for this mutation. These results support the hypothesis of a second, independent founding event for the R408W mutation on an RFLP haplotype 1 VNTR-8 chromsome background in the Irish/Celtic population.     

Fabrication of a Fixed Retrievable Implant‐supported Prosthesis Based on Electroforming: A Technical Report

This article describes a method of fabricating a fixed retrievable implant‐retained prosthesis based on electroforming. This method combines the advantages of both the cement‐ and screw‐retained prostheses, including passive fit, ease of fabrication, and retrievability. The absence of visible occlusal screw‐canals adds to its increased esthetic appeal.     

The susceptibility of young adult Americans to vaccine-preventable infections. A national serosurvey of US Army recruits

OBJECTIVE--Due to recent resurgences of measles, mumps, and rubella among young US adults, we sought to generate antibody prevalence data for national and military immunization policy evaluations. DESIGN--We used a questionnaire and serological survey of Army recruits to assess antibody status to measles, mumps, rubella, and varicella by enzyme-linked immunosorbent assay and to poliovirus types 1, 2, and 3 by microneutralization assay. SETTING--Basic training reception centers at Fort Benning, Ga., and Fort Jackson, SC. PATIENTS--The study included 1547 US Army recruits who were inducted during September and October 1989. OUTCOME MEASURES--Seronegativity by various demographic factors. RESULTS--Seronegativity rates, directly adjusted to the 15- to 24-year-old US population in 1980, were 20.7% for measles, 15.6% for mumps, 17.5% for rubella, and 6.9% for varicella. For measles, mumps, and rubella, susceptibility was less in females, blacks, and college-educated recruits, and varicella susceptibility was greater in females and blacks. Recruitment who were born after 1969 lacked measles, mumps, and rubella antibodies more often than older recruits. The adjusted seronegativity rates for poliovirus types 1, 2, and 3 were 2.3%, 0.6%, and 14.6%, respectively; trends by age, sex, and race-ethnicity were generally unremarkable. CONCLUSIONS--Among young adult Americans, susceptibility to measles, mumps, and rubella is unevenly distributed and may be substantial. Our findings support national objectives to further improve immunization coverage in school-age and adult populations and provide further impetus for legislation requiring college entrants to present evidence of having received at least two doses of measles vaccine, with one on or after entry into elementary school.     

Immunochemical characterization of Glycine max L. Merr. var Raiden, as a possible hypoallergenic substitute for cow's milk-allergic patients

Background Cows' milk allergy (CMA) is the most common cause of food allergy in infancy. The only proven treatment is the complete elimination of cows' milk proteins (CMPs) from the diet by means of hypoallergenic formulas. Soybean‐based formulae are widely used although intolerance to soy has been reported to occur in 15–40% of infants with CMA. Objective The aim of this work was to analyse the in vitro reactivity of the soybean cultivar Raiden, which naturally lacks glycinin A₄A₅B₃, to evaluate whether this genotype could be a safe CMP substitute for CMA patients. Methods The reactivity of conventional soybean (CS) and Raiden soybean (RS) genotypes and also recombinant glycinin A₄A₅B₃ and αβ‐conglycinin with casein‐specific monoclonal antibodies and CMP‐specific polyclonal serum was evaluated by immunoblotting and ELISA. A sequential competitive ELISA with the polyclonal antiserum and different soluble inhibitors was performed. In addition, an indirect ELISA with sera of atopic children with CMA was carried out to analyse the IgE‐binding capacity of the different soybean components. Results We have shown that CS contains four components that cross‐react with CMP, while RS has only one. The remaining cross‐reactive component in RS was identified as α‐subunit β‐conglycinin. By means of inhibitory ELISA, we demonstrated that CS, RS and the α‐subunit β‐conglycinin extracts inhibited the binding of CMP‐specific antibodies to the CMP‐coated solid phase. Finally, we showed that CS, RS and the recombinant proteins were recognized by human CMP‐specific IgE antibodies. Conclusion This work shows that although Raiden has fewer cross‐reactive components than conventional soybean, it still has a residual cross‐reactive component: the α‐subunit β‐conglycinin. This reactivity might make this genotype unsuitable to treat CMA and also explains adverse reactions to soybean in CMA infants.     

Schizencephaly: diagnosis and progression in utero

Schizencephaly is an unusual condition of obscure etiology. Most theories of pathogenesis postulate an in utero insult leading to maldevelopment rather than destruction of brain. The cause has most often been described as vascular or idiopathic dysgenesis. The authors report a case in which two in utero ultrasound (US) examinations performed at 31 and 36 menstrual weeks demonstrated progressive deterioration of the relatively narrow, symmetrical clefts connecting the lateral ventricles with the subarachnoid space into broad defects that corresponded to the entire distribution of the middle cerebral arteries. The findings in this case document progressive destruction of brain tissue in utero and are consistent with a vascular cause rather than a failure of formation of portions of the cerebral mantle.     

A highly sensitive and specific chemiluminescent enzyme-linked immunosorbent assay for diagnosis of active Trypanosoma cruzi infection

BACKGROUND: Chagas' disease is transmitted to man either by the bite of insects harboring Trypanosoma cruzi or by the transfusion of blood from infected donors. The conventional serologic testing as presently used in blood banks in South America is unsatisfactory, because of a high number of inconclusive and false-positive results. Other methods such as polymerase chain reaction and enzyme-linked immunosorbent assay (ELISA) with recombinant antigens have been proposed, but inherent difficulties have so far precluded their adoption in the large-scale screening required by blood banks. STUDY DESIGN AND METHODS: A highly sensitive and specific chemiluminescent ELISA using a purified trypomastigote glycoconjugate antigen and a complex epimastigote antigen was devised for the diagnosis of active T. cruzi infection. RESULTS: Chemiluminescent ELISA was 100-percent sensitive in the diagnosis of 100 cases of confirmed Chagas' disease. Inconclusive results and false-positive reactions were eliminated in a panel of 115 sera.The specificity of the chemiluminescent ELISA was 100 percent with a purified trypomastigote glycoconjugate antigen and 99.7 percent with a complex epimastigote antigen when applied to 1000 normal human sera and 288 heterologous sera from patients with other infections, including leishmaniasis, and vaccinated individuals. CONCLUSION: The chemiluminescent ELISAs provide a test that is highly sensitive (purified trypomastigote glycoconjugate and complex epimastigote antigens) and specific (purified trypomastigote glycoconjugate antigen) for Chagas' disease diagnosis. It can be used in blood bank screening and to monitor the treatment of patients undergoing chemotherapy.     

Lower Extremity Arterial Calcification on Preoperative Knee Radiographs as a Predictor of Postoperative Cardiovascular Events After Primary Total Knee Arthroplasty

Background

A cross-sectional study of total knee arthroplasty (TKA) patients was conducted to determine the association of lower-extremity arterial calcification (LEAC) with acute perioperative cardiovascular events (CVEs).

Naratriptan: biological profile in animal models relevant to migraine

The biological profile of naratriptan (N-methyl-3-(1-methyl-4-piperidinyl)-1H-indole-5-ethane-sulphona-mide), a novel 5HT_1B/1D receptor agonist, was investigated in a variety of experimental models of relevance to migraine. Naratriptan has high affinity for human recombinant 5HT_1B and 5HT_1D receptors (pKi = 8.70.03 and 8.30.1, respectively) and causes contractions of dog isolated basilar and middle cerebral artery (EC₅₀ values of 0.11 and 0.07 M, respectively). Naratriptan causes small contractions of human isolated coronary arteries (EC₅₀ value of 0.17 M; maximum contraction equivalent to 33% of 5HT maximum). In anaesthetized dogs, naratriptan causes selective vasoconstriction of the carotid arterial bed (CD₅₀ dose = 193 g kg⁻¹) and, in anaesthetized rats, naratriptan selectively inhibits neurogenic plasma protein extravasation in the dura (ID₅₀ = 4.1 g kg⁻¹). In a variety of antinociceptive tests, naratriptan has no effect even at high doses. In conscious rats and dogs, naratriptan has high oral bioavailability (71% and 95%, respectively). The data show that naratriptan is a selective agonist at 5HT_1B/1D receptors, with a pharmacological profile very similar to that of sumatriptan, albeit 2-3 fold more potent. These observations, coupled with high oral bioavailability in animals, suggest that naratriptan has the profile of an orally effective anti-migraine drug.