Fetal intestinal transplant as an accessory enteral segment

Fetal tissue transplantation has gathered considerable interest among researchers dealing with organ transplantation. A large number of studies concerning fetal intestinal transplantation have been published in the past 2 decades, almost all of them aiming to determine the feasibility of a properly functioning fetal transplant in continuity with the host's own enteral system. This study was designed to determine the absorptive capacity of the neogut in vivo, without anastomosing the transplant to the host's intestine, and to evaluate its use as an accessory enteral segment. Intestinal segments taken from Wistar albino fetuses were transplanted subcutaneously into the abdominal wall of 20 Sprague-Dawley rats. Immunosuppression was maintained by daily cyclosporin A (Cy A) 10 mg/kg injections s.c. and evaluated by determination of serum Cy A level and T-helper/T-suppressor cell ratio. The neogut was converted into a Thiry-Vella loop 2 weeks after transplantation. A test solution composed of 20% glucose and Trophamine was perfused via the stomas; glucose and amino acid absorption gradients were calculated. The gamma-glutamyl transferase (GGT) activity and mitotic index of the neogut were determined. Results were compared to those obtained from the host. There was no significant difference (P > 0.05) in glucose absorption between the neogut and the host tissue. Amino acid absorption and specific GGT activity were significantly less (P < 0.01) in the neogut. There was no significant difference (P > 0.05) between neogut and host intestine in mitotic index. Our data support the idea of using a transplanted fetal intestinal segment as an accessory feeding route.     

Cross-clade human immunodeficiency virus (HIV)-specific cytotoxic T-lymphocyte responses in HIV-infected Zambians

We have examined cross-clade HIV-specific cytotoxic T-lymphocyte (CTL) activity in peripheral blood of eight Zambian individuals infected with non-B-clade human immunodeficiency virus type 1 (HIV-1). Heteroduplex mobility assay and partial sequence analysis of env and gag genes strongly suggests that all the HIV-infected subjects were infected with clade C HIV-1. Six of eight C-clade HIV-infected individuals elicited CTL activity specific for recombinant vaccinia virus-infected autologous targets expressing HIV gag-pol-env derived from B-clade HIV-1 (IIIB). Recognition of individual recombinant HIV-1 B-clade vaccinia virus-infected targets expressing gag, pol, or env was variable among the patients tested, indicating that cross-clade CTL activity is not limited to a single HIV protein. These data demonstrate that HIV clade C-infected individuals can mount vigorous HIV clade B-reactive CTL responses.     

Characterization of a calmodulin kinase II inhibitor protein in brain

Ca2+/calmodulin-dependent protein kinase II (CaM-KII) regulates numerous physiological functions, including neuronal synaptic plasticity through the phosphorylation of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid-type glutamate receptors. To identify proteins that may interact with and modulate CaM-KII function, a yeast two-hybrid screen was performed by using a rat brain cDNA library. This screen identified a unique clone of 1.4 kb, which encoded a 79-aa brain-specific protein that bound the catalytic domain of CaM-KII alpha and beta and potently inhibited kinase activity with an IC50 of 50 nM. The inhibitory protein (CaM-KIIN), and a 28-residue peptide derived from it (CaM-KIINtide), was highly selective for inhibition of CaM-KII with little effect on CaM-KI, CaM-KIV, CaM-KK, protein kinase A, or protein kinase C. CaM-KIIN interacted only with activated CaM-KII (i. e., in the presence of Ca2+/CaM or after autophosphorylation) by using glutathione S-transferase/CaM-KIIN precipitations as well as coimmunoprecipitations from rat brain extracts or from HEK293 cells cotransfected with both constructs. Colocalization of CaM-KIIN with activated CaM-KII was demonstrated in COS-7 cells transfected with green fluorescent protein fused to CaM-KIIN. In COS-7 cells phosphorylation of transfected alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid-type glutamate receptors by CaM-KII, but not by protein kinase C, was blocked upon cotransfection with CaM-KIIN. These results characterize a potent and specific cellular inhibitor of CaM-KII that may have an important role in the physiological regulation of this key protein kinase.     

Genetic variants of human T-lymphotrophic virus type II in American Indian groups

The human T-lymphotropic virus type II (HTLV-II) is found in many New World Indian groups in North and South America and may have entered the New World from Asia with the earliest migration of ancestral Amerindians over 15,000 years ago. To characterize the phylogenetic relationships of HTLV-II strains infecting geographically diverse Indian populations, we used polymerase chain reaction to amplify HTLV-II sequences from lymphocytes of seropositive Amerindians from Brazil (Kraho, Kayapo, and Kaxuyana), Panama (Guaymi), and the United States (the Navajo and Pueblo tribes of the southwestern states and the Seminoles of Florida). Sequence analysis of a 780-base pair fragment (located between the env gene and the second exons of tax/rex) revealed that Amerindian viruses clustered in the same two genetic subtypes (IIa and IIb) previously identified for viruses from intravenous drug users. Most infected North and Central American Indians had subtype IIb, while HTLV-II infected members of three remote Amazonian tribes clustered as a distinct group within subtype IIa. These findings suggest that the ancestral Amerindians migrating to the New World brought at least two genetic subtypes, IIa and IIb. Because HTLV-II strains from Amazonian Indians form a distinct group within subtype HTLV-IIa, these Brazilian tribes are unlikely to be the source of IIa viruses in North American drug users. Finally, the near identity of viral sequences from geographically diverse populations indicate that HTLV-II is a very ancient virus of man.     

Recent advances in the molecular genetics of hereditary retinal dystrophies with primary involvement of the macula

Hereditary dystrophies of the central retina and choroid are a heterogeneous group of disorders characterized by preferential loss of macular function and consequently loss of central and color vision. The primary causes leading to the degenerative processes are largely unknown although recent progress in human molecular genetics is most promising in providing novel insights into the basic biochemical mechanisms of these dystrophies. To date, the disease loci of more than 20 maculopathies including cone and cone-rod dystrophies have been mapped to specific chromosomal regions of which seven disease genes have already been identified. As the goals of the Human Genome Initiative approach completion, the cloning of the genes involved in the etiology of human retinopathies will be greatly simplified providing the basis for a more comprehensive understanding of retinal function and dysfunction. In addition, these advances will facilitate the identification of individuals at risk at a presymptomatic or initial stage of disease, thus creating a unique opportunity to devise novel therapeutic strategies that will primarily be aimed at an early intervention with the potential to either delay or even prevent the development of disease pathology.     

Clinical correlation of neuropsychological tests with 1H magnetic resonance spectroscopy in hepatic encephalopathy

The mortality from coronary and cerebrovascular diseases is higher in Finnmark County than in other Norwegian counties. In a population-based cohort study, we compared the incidence of myocardial infarction, stroke, and diabetes mellitus in different ethnic groups in Finnmark. A total of 10,622 subjects of Norse, Sami, and Finnish origin were followed for 14 years. During approximately 150,000 person-years, we identified 509 and 84 cases of myocardial infarction, 107 and 75 cases of stroke, and 96 and 73 cases of clinical diabetes mellitus among men and women, respectively. A total of 533 men and 199 women died. Norse subjects born outside of Finnmark had the most favorable risk factor levels and, in general, the lowest incidence of disease. Men of Finnish origin had a higher incidence rate of all endpoints than other men, and Finnish women had a higher incidence rate of myocardial infarction than other women. Sami women were more obese but did not have a higher diabetes mellitus incidence than other women. After adjustment for major cardiovascular risk factors and height, most ethnic differences were attenuated.