Resistance of HIV type 1 to proteinase inhibitor Ro 31-8959

During replication of human immunodeficiency virus type 1 (HIV-1), proteolytic cleavage of Gag and Gag-Pol precursor proteins into different functional protein subunits is catalyzed by the viral proteinase, and this enzyme is the target of the antiviral proteinase inhibitor, Ro 31-8959. We investigated in vitro which HIV mutants with reduced sensitivity to Ro 31-8959 emerged during proteinase inhibition treatment; from three different HIV-1 strains, comparable progeny virus resistant to proteinase inhibitor were found, whereas the same experimental protocol detected no resistant HIV-2 mutants. Molecular analysis of the mutations underlying resistance revealed a multistep mechanism in which an amino acid exchange was common to all resistant isolates, and in all experiments preceded further exchanges at position 90 (leucine to methionine) and/or at position 54 (isoleucine to valine). For wild-type strains the 90% inhibitory concentrations of Ro 31-8959 were close to 20 nM, whereas HIV-1 mutants with all 3 amino acid exchanges had more than 50-fold increased 90% inhibitory concentrations (above 1000 nM). The primary event (Gly-48 to valine) occurs at the hinge of the flaps of the proteinase, thus hampering entry of the inhibitor to the active center and suggesting steric hindrance. Detailed knowledge of this stereotypic process could open inhibitor design, thus preventing conceivable escape of resistant virus on proteinase inhibitor action.

The effects of distention of the colon during air-contrast barium enema on colonic morphology: anatomic correlation

Radiologic and pathologic findings are snapshots of disease processes that may vary with a host of dynamic variables. This pictorial essay shows how the presence and visibility of the innominate grooves of the colon are a function of colonic distention. This article also shows how each layer of the colonic wall, including the epithelium, muscularis mucosae, and muscularis propria, changes dramatically in thickness with varying degrees of colonic distension. These anatomic changes are documented by barium enema radiography, specimen radiography, dissecting photomicrography, and histology. These observations have important implications for the interpretation of radiologic and pathologic findings in both normal and diseased states.

Phosphodiesterase type IV inhibition. Structure-activity relationships of 1,3-disubstituted pyrrolidines

The synthesis of 1,3-disubstituted pyrrolidines 2 and their activities as type IV phosphodiesterase (PDE) inhibitors are described. Various groups were appended to the nitrogen of the pyrrolidine nucleus to enable structure-activity relationships to be assessed. Groups which render the pyrrolidine nitrogen of 2 nonbasic yielded potent PDE-IV inhibitors. Analogs of amides, carbamates, and ureas of 2 were synthesized to determine the effects that substitution on these functional groups had on PDE-IV inhibitor potency. The structural requirements for PDE-IV inhibitor potency differed among the three classes. A representative amide, carbamate, and urea (2c,d,h) were shown to be > 50-fold selective for inhibiting PDE-IV versus representative PDEs from families I-III and V. Furthermore, these same three inhibitors demonstrated potent functional activity (IC50 < 1 microM) by inhibiting tumor necrosis factor-alpha (TNF-alpha) release from lipopolysaccharide (LPS)-activated purified human peripheral blood monocytes and mouse peritoneal macrophages. These compounds were also tested orally in LPS-injected mice and demonstrated dose-dependent inhibition of serum TNF-alpha levels.

Functional separation of global and local stereopsis investigated by cross-adaptation

Reports that brain lesions may differentially affect global and local stereopsis suggest that anatomically separate mechanisms underlie these two functions. We demonstrate here that adaptation to global stereograms induces an after-effect on local stereopsis as well as on global stereopsis, showing that the two mechanisms cannot be entirely separate. We suggest that global stereopsis depends upon an interaction between primary visual area V1 and higher brain areas such as inferotemporal cortex.

Psychological characteristics and the effectiveness of patient-controlled analgesia

We have evaluated the level of state and trait anxiety, neuroticism, extroversion and coping style as predictors of the effectiveness of patient-controlled analgesia (PCA) in 110 patients undergoing total abdominal hysterectomy. After operation patients were allocated to receive pain control with either PCA or i.m. injections (IMI). Pain was assessed using the short form McGill pain questionnaire at 6, 18 and 24 h after operation, and by recording the amount of analgesic consumed in the first 24 h after surgery. Both state anxiety and coping style were significant predictors of postoperative pain, irrespective of the method of analgesia used. Patients using PCA experienced significantly better pain control than those receiving IMI. However, it was those with high levels of state anxiety who experienced the greatest reduction in pain with PCA. In addition to achieving better pain control, patients who received PCA used significantly less analgesia and were discharged earlier than patients who received IMI.

[Role of segmental buckling surgery in treatment of stages B and C proliferative vitreoretinopathy detachment. A long-term follow-up]

BACKGROUND

The following questions should be addressed: (1) Is minimal detachment surgery justified in treating detachments with preoperative PVR stage B or C? (2) Can this reattach the retina with stabilization or regression of PVR?

MATERIALS AND METHODS

72 PVR detachments stage B or C (38 C1, 11 C2, 1 C3) were treated by cryopexy, segmental buckling (n = 68) or balloon (n = 4) without drainage or vitrectomy. Reoperation (n = 10) was done without cerclage or vitrectomy. The follow-up of patients alive is 11 to 13 1/2 years and of all patients (31 died) x 7 1/2 years.

RESULTS

After the primary operation the retina was reattached in 79%, partially in 15% and detached in 6%. An "early" redetachment (< or = 6 months postoperatively) occurred in 8.3%, no redetachment > 6 months to < 9 years and "late" redetachment (9-13 1/2 years postoperatively) in 2.8%. After reoperation (n = 10) the retina was reattached in 85%, partially in 3%, and detached in 12%. 34 eyes had delayed resorption (2 weeks to 18 months) with a residual concave detachment in area of starfolds and tractions, resulting in dry starfolds or their disappearance after months. Postoperatively there were no rubeosis iridis, no secondary glaucoma and no phthisis bulbi. Subsequent macular pucker developed in 12 eyes, which were not treated by vitreoretinal surgery. Six months postoperatively visual acuity was: 26x 20/60-20/25; 16x 20/200-20/100; 30x < or = 20/400 which was not statistically significant different (p = 0.549) after x 7 1/2 years.

CONCLUSION

Primary treatment of a PVR detachment stage B or C1/C2 with cryopexy and segmental buckling and nondrainage seems justified to test for the chance of PVR-regression. The retina was reattached in 8 of 10 patients x 7 1/2 years postoperatively after primary operation without reoperation or vitrectomy and visual acuity was 20/60-20/25 in every third patient, thus implying a lack of late serious complications.

Interocular transfer of expansion, rotation, and translation motion aftereffects

The motion aftereffect demonstrates the existence of direction-selective mechanisms in the visual system. However, direction-selective cells exist within many visual areas, including V1 and MT/V5. Can motion aftereffects be generated within each of these areas? In visual cortical areas beyond V1 almost all cells are binocular, whereas a smaller percentage are binocular in V1. The degree of binocularity can be revealed psychophysically by assessing interocular transfer. Interocular transfer of motion aftereffects generated from expanding rotating, and translating dynamic random-dot patterns were therefore compared, since these stimuli should activate cells in higher visual areas selectively. Partial interocular transfer was found that was greater for expansion and rotation than for translation. The results support the involvement of higher visual areas in motion aftereffects to complex animation sequences.

Endothelial cell storage and release of endothelin as a cardioregulatory mechanism

Coronary vascular endothelial cells release substances into the coronary circulation that modify the contractile system of cardiac myocytes, and cardiac myocytes may release factors that modulate the secretion of cardioregulatory substances by endothelial cells. This regulatory loop is sensitive to the rate of coronary flow and tissue oxygen tension. In the present study, coronary venous effluent from isolated perfused hearts and the contents of the coronary vascular endothelial cells have been collected, the latter by disrupting the cells with coronary perfusion at high pressure. The relative amounts of upregulating and downregulating factors in both collections have been estimated by assaying their effects on the contractility of isolated cardiac trabeculas. The amount of upregulating factor stored in the endothelial cells is sensitive to the rate of coronary flow just before disruption of the cells. The quantity of endothelin in the coronary venous effluent and in the vascular endothelial cell contents was measured by radioimmunoassay and compared with the degree of upregulation of contractility produced by the two types of solutions. Upregulation was never produced in the absence of endothelin. The extent of the increase in contractility that was observed with endothelial cell contents correlated with the concentration of endothelin and was approximately the same as the increase in contractility from similar concentrations of endothelin added to standard Krebs' solution. The amount of the increase in contractility from coronary effluent could be accounted for by the concentration of endothelin in the effluent with the additional presence of some downregulating factor as well. The endothelin antagonist BQ123 inhibited the upregulation from coronary perfusate. It appears that endothelin alone can account for all of the upregulation of contractility produced by the vascular endothelial cells. Coronary flow, probably through shear forces, seems to regulate the production of endothelin possibly from an inactive precursor. Tissue oxygen tension appears to modulate the rate of release of the endothelin from endothelial cells though substances released by cardiac myocytes or other cells in the tissue. The downregulating factor is stored to a much smaller extent.

Renin and renin mRNA in proximal tubules of the rat kidney

The present study was undertaken to assess the presence of renin enzymatic activity and renin mRNA in proximal tubules of rat kidneys, and to determine the effect of converting enzyme inhibition (CEI) on proximal tubule renin gene expression. Proximal convoluted tubules (PCT), proximal straight tubules (PST), outer medullary collecting ducts (OMCD), and glomeruli (Gloms) were isolated by microdissection. Renin activity was measured in sonicated segments by radioimmunoassay. Renin mRNA levels were assessed using a quantitative PCR. Renin activity in PCT averaged 51 +/- 15 microGU/mm compared to 405 +/- 120 microGU/glomerulus. No measurable renin activity was found in PST and OMCD. Renin activity in both glomeruli and tubules had the same pH optimum, between 7.0 and 7.5. Renin mRNA was consistently detectable in cDNA prepared from PCT and PST, although its abundance per mm tubule was about 1/500th that found in one glomerulus. Renin mRNA was not detectable in OMCD. Tubular renin PCR product identity was confirmed by restriction digestion. CEI administration increased glomerular renin activity and renin mRNA, but not proximal tubular renin. The absence of a stimulatory effect of CEI on proximal tubule renin gene expression suggests the operation of different intracellular signals in control of renin synthesis in the proximal tubule than in the vascular compartment.

Prevalence of human T-cell lymphotropic virus infections in Germany

The extent of human T-cell lymphotropic retrovirus HTLV-I and HTLV-II infections in the general population in central Europe has not been investigated fully. Two hundred forty-eight thousand blood donors from southern Germany were examined serologically for antibodies to the human lymphotropic retroviruses HTLV-I and HTLV-II: 0.021% were confirmed positive and 0.056% were "indeterminate". A limited number of seropositives and "indeterminate" samples were analyzed by polymerase chain reaction (PCR): the seropositives were confirmed as positive and 43% of the "indeterminate" samples were PCR-positive. The range of 0.021% HTLV-positives in 248,000 donors, i.e. about two in 10,000 individuals, mirrors closely the published data for the United States.

Linear algebraic transformations of the bidomain equations: implications for numerical methods

A mathematical framework is presented for the treatment of the bidomain equations used to model propagation in cardiac tissue. This framework is independent of the model used to represent membrane ionic currents and incorporates boundary conditions and other constraints. By representing the bidomain equations in the operator notation L phi = F, various algebraic transformations can be expressed as PLQ-1 psi = PF, where P and Q are linear operators. The authors show how previous work fits into this framework and discuss the implications of various transformation for numerical methods of solution. Although such transformations allow many choices of independent variable, these results emphasize the fundamental importance of the transmembrane potential.

Origin of endothelial cells that line expanded polytetrafluorethylene vascular grafts sodded with cells from microvascularized fat

PURPOSE

Cell transplantation onto prosthetic vascular grafts remains an attractive technique to reduce the thrombogenicity of polymeric materials. In this study we evaluated whether autologous cells isolated from falciform ligament fat and transplanted onto the lumenal surface of 4 mm expanded polytetrafluorethylene grafts were the same cells present on the surface of these grafts when they were explanted from canine carotid arteries 3 weeks after their implantation.

METHODS

The fluorescent dye PKH-26 was used to label transplanted cells to evaluate their fate after implantation of grafts as carotid artery replacements. This fluorescent dye homogeneously labeled all cells in the primary cell isolate.

RESULTS

In vitro studies indicated that dye labeling was nontoxic, as evidenced by the normal growth characteristics of fluorescently labeled cells compared with nonlabeled cells. Immunocytochemical analysis of microvascularized fat before cell isolation determined that approximately 90% of the cells stained positive for von Willebrand factor2. At the time of explant, seeded grafts exhibited a nonthrombogenic lumenal cell lining as evidenced by the lack of adherent platelets or fibrin. Cells on the lumenal surface of grafts exhibited PKH-26 fluorescence emission. In addition, these cells expressed von Willebrand factor and actively sequestered DiI-acetylated low-density lipoprotein.

CONCLUSIONS

We conclude that sodding of prosthetic grafts with autologous microvascularized fat-derived cells results in the formation of an endothelial cell lining on the lumenal flow surface. These endothelial cells are the same cells placed on the lumenal surface of the graft at the time of initial cell transplantation. Finally, a confluent monolayer forms after high-density cell sodding by the process of cell adherence and spreading, without the need for cell proliferation.

The Mayo Clinic experience with the cochlear implant

The implantation of a cochlear electronic prosthetic device is an acceptable means of improving the communication ability of pre- and postlingually deafened children and adults. A significant number of patients in this series are in the senior citizen age group. It has been beneficial in improving communication ability in selected profoundly deafened individuals. There has been a significant improvement in the cochlear electronic prosthetic device since the initial report of Djourno in 1957.

Recurrence of breast carcinoma following immediate reconstruction: a 13-year review

To evaluate the effect of immediate reconstruction on the incidence, location, detection, and treatment of recurrent breast cancer, a review of 306 patients operated on according to a standard protocol during the 10-year period 1979 through 1988 was performed. Reconstruction techniques included submuscular implants (207), tissue expanders (84), and musculocutaneous flaps (15). During a minimum follow-up period of 3 years with a mean of 6.4 years, 60 patients (19.6 percent) developed recurrent disease, at a mean interval to recurrence of 31 months. The first locations of recurrences were local (16), regional (11), and systemic (33). Recurrence rates by stage included stage I, 7 patients (5.2 percent); stage II, 45 patients (32.1 percent); and stage III, 8 patients (40 percent). It was not possible to include comparisons with internal control groups of patients in our institution who were not reconstructed or who had delayed reconstructions, thereby preventing conclusions based on such comparisons. Our recurrence data are similar to literature reports of recurrence rates in patients who were not reconstructed after mastectomy. Detection and treatment of recurrences were not inhibited by the reconstructions. When radiation therapy was used in the treatment of local recurrences, the development of symptomatic capsular contracture was recorded in 58 percent of the patients.

c-fos-like immunoreactivity in the cat's neuraxis following moderate hypoxia or hypercapnia

The overall pattern of c-fos immunoreactivity was studied in the brainstem and spinal cord of cats subjected to moderate hypoxia or hypercapnia. In control cats (normoxic, normocapnic), c-fos was expressed mainly in pontine and periaqueductal grey but not in brainstem structures engaged in respiratory control nor in the spinal cord. Both hypoxia and hypercapnia induced c-fos expression in the parabrachial area (pneumotaxic center). In the retrotrapezoid nucleus, a structure involved in respiratory rhythmogenesis and chemoreception, immunoreactivity was detected in hypoxic but not in hypercapnic cats. Neurons in the nucleus raphe pallidus preferentially expressed c-fos in response to hypercapnia. Labelled neurons were concentrated in the dorsal and gelatinosus subnuclei of the solitary tract following hypoxia and hypercapnia, respectively. Our data suggest that some neurons that express c-fos in hypoxic or hypercapnic cats may be involved in coordination of cardiovascular and respiratory function.

CDC44: a putative nucleotide-binding protein required for cell cycle progression that has homology to subunits of replication factor C

To investigate the means by which a cell regulates the progression of the mitotic cell cycle, we characterized cdc44, a mutation that causes Saccharomyces cerevisiae cells to arrest before mitosis. CDC44 encodes a 96-kDa basic protein with significant homology to a human protein that binds DNA (PO-GA) and to three subunits of human replication factor C (also called activator 1). The hypothesis that Cdc44p is involved in DNA metabolism is supported by the observations that (i) levels of mitotic recombination suggest elevated rates of DNA damage in cdc44 mutants and (ii) the cell cycle arrest observed in cdc44 mutants is alleviated by the DNA damage checkpoint mutations rad9, mec1, and mec2. The predicted amino acid sequence of Cdc44p contains GTPase consensus sites, and mutations in these regions cause a conditional cell cycle arrest. Taken together, these observations suggest that the essential CDC44 gene may encode the large subunit of yeast replication factor C.

[A new variant of the simian T-lymphotropic retrovirus type I (STLV-IF) in the Sukhumi colony of hamadryas baboons]

Polymerase chain reaction (PCR) was developed for the detection of simian T-lymphotropic virus type 1 (STLV-1) infection of P. hamadryas and direct sequencing using oligo-nucleotide primer pairs specific for the tax and env regions of the related human T-lymphotropic virus type 1 (HTLV-1). Excellent specificity was shown in the detection of STLV-1 provirus in infected baboons by PCR using HTLV-1-derived primers. The nucleotide sequences of env 467bp and tax 159bp of the proviral genome (env position 5700-6137, tax position 7373-7498 HTLV-1, according to Seiki et al., 1983) derived from STLV-1-infected P. hamadryas were analysed using PCR and direct sequencing techniques. Two STLV-1 isolates from different sources (Sukhumi main-SuTLV-1 and forest stocks-STLV-1F) were compared. Two variants of STLV-1 among P. hamadryas with different level of homology to HTLV-1 were wound (83.8% and 95.2%, respectively). A possible role of nucleotide changes in env and tax sequenced fragments and oncogenicity of STLV-1 variants is discussed.

The Sukhumi primate monkey model for viral lymphomogenesis: high incidence of lymphomas with presence of STLV-I and EBV-like virus

T-cell leukemia virus-like proviral sequences (STLV-I) as well as EBV-like sequences were detected in PBLs and tissues of non-human primates (Papio hamadryas baboons, Green monkeys and Macaca arctoides; Sukhumi Primate Center/Georgia) by PCR. Surprisingly, two different types of STLV-I within Papio hamadryas baboons were found. One of its represents the baboon prototype STLV-I-Su described earlier, present in lymphomatous baboons from the "high-lymphoma stock", which shows about 83% homology to HTLV-I and 85% to STLV-I in the env and tax genes. The inter-individual variability within this subtype is very low (about 1% in the tax gene). The second subtype was mainly found in asymptomatic animals from the control colony and showed in the env gene 95% homology to HTLV-I, but only 82% to the prototype baboon sequence. The presence of two subtypes within the Sukhumi baboon population might be interesting in respect to the inoculation experiments with human leukemic blood and to possible interspecies transmissions. The nature of the Herpes Papio-virus was elucidated as EBV-like and the homology to the human EBV was > 90% in the polymerase gene. The homologies between different monkey species were between 92 and 96% and also here two subtypes within the baboons were detected. This is the first direct demonstration by sequencing that the Herpes Papio virus is closely related to EBV. For further studies of this animal model, rabbits were inoculated with cells originated from lymphomatous baboons and macaques. The rabbits developed generalized lymphomas lethal within 1-2 months. EBV-like and STLV-I-like sequences could be detected by PCR and sequencing showed 99-100% identity to the inoculum, indicating in fact the transmission from monkey to rabbit. These animal models seem to be very suitable for the elucidation of the pathogenesis of human HTLV-I associated T-cell leukemia/lymphoma and might be further on used for therapeutical and preventative studies.