Dimerization of human immunodeficiency virus type 1 RNA involves sequences located upstream of the splice donor site.

The retroviral genome consists of two homologous RNA molecules associated close to their 5' ends. We studied the spontaneous dimerization of four HIV-1 RNA fragments (RNAs 1-707, 1-615, 311-612, and 311-415) containing the previously defined dimerization domain, and a RNA fragment (RNA 1-311) corresponding to the upstream sequences. Significant dimerization of all RNAs is observed on agarose gels when magnesium is included in the electrophoresis buffer.

Primary nonfunction of islet xenografts: the role of macrophages.

Primary nonfunction (PNF) of hamster islets occurs when they are transplanted under the kidney capsule of diabetic Lewis rat recipients. PNF is absent if the islets are grafted into the liver. Previous results have indicated that macrophages might be involved in the phenomenon of PNF.

Small bowel transplantation: an overview.

Small bowel transplantation (SBT) would, in theory, be the treatment of choice for patients suffering from the short bowel syndrome. Although SBT has been done with a considerable degree of success in some centers [36, 145], it is by no means an established or widely applicable therapy for those with short bowel syndrome. The small bowel is unique among vascularized organ grafts because it not only elicits a vigorous rejection reaction but is also capable of inducing graft-versus-host disease (GVHD).

The chemosensitizer cyclosporin A enhances the toxic side-effects of doxorubicin in the rat.

The feasibility of using chemosensitizers in the circumvention of P-glycoprotein-mediated multidrug resistance has been shown in many studies. We recently reported on the chemosensitizing effect of cyclosporin A (CsA) on doxorubicin in a rat solid tumour model. Using the same experimental design we investigated the side-effects of the combination treatment.

Modified nucleotides of tRNA(3Lys) modulate primer/template loop-loop interaction in the initiation complex of HIV-1 reverse transcription.

In all retroviruses, reverse transcription is primed by a tRNA whose 3' end 18 nucleotides are complementary to the so called viral primer binding site. Previous work showed that reverse transcription of HIV-1 RNA is initiated by tRNA(3Lys). Using a variety of chemical and enzymatic structural probes, we investigated the interactions between HIV-1 RNA and its natural primer tRNA(3Lys).

Long-term survival of DLA-matched segmental small-bowel allografts in dogs.

The aim of this study was to investigate the combined effect of DLA matching and immunosuppressive therapy on the survival of segmental small-bowel allografts in dogs. Orthotopic segmental small-bowel transplantations (25 to 30% of total small bowel length) were performed in two stages: first a heterotopic segmental small bowel transplantation, followed after 5 to 8 weeks by a second-stage operation during which the heterotopic graft was placed in an orthotopic position and the native small bowel was resected. All dogs received cyclosporine immunosuppression.

Drug resistance in rat colon cancer cell lines is associated with minor changes in susceptibility to cytotoxic cells.

The development of resistance to anticancer drugs urges the search for different treatment modalities. Several investigators have reported the concomitant development of drug resistance and resistance to natural killer (NK), lymphokine-activated killer (LAK) or monocyte/macrophage cell lysis, while others described unchanged or even increased susceptibility. We investigated this subject in the rat colon carcinoma cell line, CC531-PAR, which is intrinsically multidrug-resistant (MDR), and in three sublines derived from this parental cell line: a cell line with an increased MDR phenotype (CC531-COL), a revertant line from CC531-COL (CC531-REV), which demonstrates enhanced sensitivity to anticancer drugs of the MDR phenotype, and an independently developed cisplatin-resistant line (CC531-CIS).

Blood transfusions and prognosis in colorectal cancer.

Background: Blood transfusions may adversely affect the prognosis of patients treated surgically for cancer, although definite proof of this adverse effect has not been reported.

Methods: We carried out a randomized trial to investigate whether the prognosis in patients with colorectal cancer would be improved by a program of autologous blood transfusion as compared with the current practice of allogeneic transfusion. Patients in the autologous-transfusion group were required to donate two units of blood before surgery.

The value of in vivo electrophysiological measurements for monitoring functional adaptation after massive small bowel resection in the rat.

The process of functional adaptation after extensive small bowel resection is complex and imprecisely understood. In vivo electrophysiological measurements for monitoring the functional adaptive process after massive small bowel resection in Brown-Norway rats were evaluated. Rats underwent either a sham operation (SH) or a 90% small bowel resection (SB).

Blood donation leads to a decrease in natural killer cell activity: a study in normal blood donors and cancer patients.

Transfusion-induced immunosuppression has long been known to be beneficial for organ transplantation patients, but recent retrospective studies suggest that blood transfusions may be detrimental for patients with cancer. If autologous blood is used to avoid immunosuppression, the assumption is that the procedure, involving blood donation, is immunologically neutral. In the present study, this assumption was evaluated by monitoring 33 normal blood donors and 16 colorectal cancer patients before and after donation of 1 (500 mL) and 2 units of blood, respectively.

Functional sites in the 5' region of human immunodeficiency virus type 1 RNA form defined structural domains.

The 5' region of HIV-1 RNA contains functional elements involved in key steps of the retroviral cycle, such as genomic RNA transcription, splicing, translation, dimerization or initiation of reverse transcription. In the present work, we investigated the conformation of the first 500 nucleotides covering the RNA leader and the 5' gag coding sequences of HIV-MAL, using chemical probing. We provide detailed information on almost each nucleotide at one of their Watson-Crick positions and on position N-7 of purines.

Effects of donor pretreatment with antilymphocyte serum and cyclosporin on rejection and graft-versus-host disease after small bowel transplantation in immunosuppressed and nonimmunosuppressed rats.

After fully allogeneic small bowel transplantation, both graft-versus-host disease (GVHD) and rejection may occur. Donor pretreatment may prevent GVHD, but this sometimes leads to accelerated graft rejection. To study a possible balance between GVHD and rejection, fully allogeneic total orthotopic small bowel transplantation was performed in rats using the WAG-to-BN donor-host combination.

In vitro and in vivo chemosensitizing effect of cyclosporin A on an intrinsic multidrug-resistant rat colon tumour.

Colon tumours are intrinsically resistant to chemotherapy and most of them express the multidrug transporter P glycoprotein (Pgp). Whether this Pgp expression determines their resistance to anticancer agents in patients is not known. We report here on the reversibility of intrinsic multidrug resistance in a syngeneic, solid tumour model.

Prognostic impact of blood transfusions on disease-free survival in colorectal carcinoma.

Blood transfusions have been indicated as having an adverse effect on the prognosis of patients treated surgically for cancer. We carried out a randomized trial to investigate whether a predeposit autologous blood transfusion program improved prognosis in patients with colorectal cancer as compared to the current practice of allogeneic transfusion. This appeared not to be the case.

[Major and minor changes in the electrocardiogram of the hypertensive patient].

Objective: To determine the prevalence and characteristics of electrocardiograph deviation in such hypertensive patients.

Design: Retrospective descriptive study of a representative sample of patients with high blood pressure. SITE.

Functional aspects of small-bowel transplantation in rats.

Although clinical small-bowel transplantation is still severely hindered by rejection of the graft, prolonged graft survival can be achieved by using cyclosporin A in several experimental models of small-bowel transplantation. In an immunologically quiescent phase after transplantation, the important question arises whether a small-bowel allograft has enough functional capacity to maintain a normal nutritional status. We investigated the functional capacity of orthotopic small-bowel transplants and evaluated the ability of the total small-bowel transplant to absorb orally given cyclosporin in the early postoperative period and the effect of this oral cyclosporin treatment on allograft survival as compared with intramuscular administration.