Closed-loop machine-controlled CPR system optimises haemodynamics during prolonged CPR.

OBJECTIVES: We evaluated the feasibility of optimising coronary perfusion pressure (CPP) during cardiopulmonary resuscitation (CPR) with a closed-loop, machine-controlled CPR system (MC-CPR) that sends real-time haemodynamic feedback to a set of machine learning and control algorithms which determine compression/decompression characteristics over time. BACKGROUND: American Heart Association CPR guidelines (AHA-CPR) and standard mechanical devices employ a "one-size-fits-all" approach to CPR that fails to adjust compressions over time or individualise therapy, thus leading to deterioration of CPR effectiveness as duration exceeds 15-20 â€‹min. METHODS: CPR was administered for 30 â€‹min in a validated porcine model of cardiac arrest. Intubated anaesthetised pigs were randomly assigned to receive MC-CPR (6), mechanical CPR conducted according to AHA-CPR (6), or human-controlled CPR (HC-CPR) (10). MC-CPR directly controlled the CPR piston's amplitude of compression and decompression to maximise CPP over time. In HC-CPR a physician controlled the piston amplitudes to maximise CPP without any algorithmic feedback, while AHA-CPR had one compression depth without adaptation. RESULTS: MC-CPR significantly improved CPP throughout the 30-min resuscitation period compared to both AHA-CPR and HC-CPR. CPP and carotid blood flow (CBF) remained stable or improved with MC-CPR but deteriorated with AHA-CPR. HC-CPR showed initial but transient improvement that dissipated over time. CONCLUSION: Machine learning implemented in a closed-loop system successfully controlled CPR for 30 â€‹min in our preclinical model. MC-CPR significantly improved CPP and CBF compared to AHA-CPR and ameliorated the temporal haemodynamic deterioration that occurs with standard approaches.

Glomerulosclerosis and viral gene expression in HIV-transgenic mice: role of nef.

BACKGROUND: Human immunodeficiency virus (HIV)-associated nephropathy is characterized by focal segmental glomerulosclerosis and microcystic tubular dilation. We have previously described a mouse transgenic for a Deltagag-pol HIV-1 genome, which develops glomerulosclerosis, cutaneous papillomas, and cataracts. METHODS: We developed mice transgenic for a Deltagag-pol-nef HIV genome in order to investigate the role of the nef gene in these phenotypes. RESULTS: One transgenic line, X5, expressed HIV mRNA in kidney and consistently manifested focal segmental glomerulosclerosis and tubular dilation by six weeks of age. Northern analysis indicated that renal transgene expression was higher in the Deltagag-pol-nef mice compared with the Deltagag-pol mice. In situ hybridization and immunostaining demonstrated HIV RNA and protein expression within the glomerular epithelial cells and tubular epithelial cells. These cell types showed histologic evidence of toxicity, including vacuolation and detachment from basement membrane, and exhibited increased rates of apoptosis. These data suggest that the renal disease seen in the Deltagag-pol-nef transgenic mouse may be caused by the expression of HIV genes within renal epithelial cells, that this expression may induce cellular toxicity, including apoptosis, and that nef is not required for the induction of renal disease. We have previously described mice bearing the nef gene, which do not manifest renal disease. In further experiments, Deltagag-pol-nef mice were bred with nef mice; these dual-transgenic mice developed renal disease that generally resembled that seen in Deltagag-pol-nef mice, but with somewhat more severe glomerulosclerosis and less severe tubulointerstitial injury. RESULTS: The results of these transgenic studies suggest that the role of nef is complex and may act both to reduce transgene expression and to potentiate glomerular injury induced by other HIV-1 gene products.

Molecular cloning and characterization of a highly basic protein, IA-4, expressed in pancreatic islets and brain.

A substraction library was constructed from mouse insulinoma (betaTC-1) and glucagonoma (alphaTC-1) cell lines. Differential screening and sequencing revealed a novel cDNA clone, IA-4, which was expressed in the islets of Langerhans and the brain. IA-4 cDNA is 1,007 bp in length and predicts a protein of 187 amino acids with a molecular mass of 19,940 D. Examination of the amino acid sequence showed a high content of arginine (18.7%), proline (14.4%), alanine (16.0%), leucine (13.4%) and glycine (9.6%). The deduced pI value is 12.5 indicating a highly basic protein. Northern blot analysis revealed a 1-kb mRNA highly expressed in brain, trigeminal ganglia and cell lines of neuroendocrine origin. Rabbit polyclonal antiserum raised against a synthetic IA-4 peptide, designated Pep-1, not only reacted with IA-4 recombinant protein, but also immunostained the islets of Langerhans and large neurons of the hippocampus, cerebral cortex, spinal cord, dorsal ganglia and Purkinje cells of the cerebellum. The high expression of IA-4 protein in neuroendocrine cells and its unique amino acid sequence suggest that IA-4 may have an important, but still undetermined, function in these special cell types.

Human chorionic gonadotropin hormone prevents wasting syndrome and death in HIV-1 transgenic mice.

At birth, transgenic mice, homozygous for the HIV-1 provirus pNL4-3, deleted in gag/pol, are normal in appearance and weight. Within several days after birth, the pups develop a syndrome characterized by dry, scaly, hyperkeratotic skin, growth failure, and death. The possibility that the homozygous embryos are being protected during gestation by a maternal factor led us to treat the newborn animals with various pregnancy-related hormones including human chorionic gonadotropin (hCG), estrogen, progesterone, and dexamethasone. Treatment with hCG prevented death, led to normal growth, and markedly reduced skin lesions. In contrast to the skin of the untreated homozygous pups, which expressed high levels of HIV mRNA and proteins (i.e., gp120 and Nef), the skin of the hCG-treated pups showed a marked reduction in both HIV mRNA and proteins. Discontinuation of hCG resulted in the reappearance of HIV transcripts and proteins, skin lesions, and growth failure resulting in death. In addition, HIV transcripts and proteins were reduced significantly in heterozygous mothers during pregnancy, but reappeared after parturition. Similarly, hCG treatment resulted in a decrease of HIV proteins in the skin of nonpregnant heterozygous transgenic mice. These findings suggest that the inhibiting effect of hCG on HIV expression may be clinically useful in the treatment of HIV infections, and may be responsible, during pregnancy, for the low transmission of HIV from infected mothers to their offspring.

Transplantation of skin from human immunodeficiency virus type 1-transgenic mice to normal congenic mice results in graft rejection.

Skin from mice transgenic (Tg) for part of the human immunodeficiency virus type 1 (HIV-1) genome was transplanted onto normal mice of the same strain. All Tg grafts were rejected within 29 days. In contrast, skin from normal mice that was transplanted to HIV-1-Tg recipients remained viable for > 67 days. Histologic examination of Tg grafts on normal mice showed evidence of monocytic infiltrates. Monocytic infiltrates were not observed, however, when either normal or Tg skin was transplanted onto Tg mice. Immunohistologic staining verified the presence of gp120 protein expression in the Tg-transplanted skin but not in adjacent normal skin. It is concluded that the Tg mice are immunologically tolerant to the HIV-1 gene products they express.

Cutaneous disorders and viral gene expression in HIV-1 transgenic mice.

Patients infected with HIV-1 experience several hyperproliferative skin disorders, including seborrheic dermatitis, ichthyosis, and psoriasis. Transgenic mice carrying a subgenomic HIV-1 proviral construct lacking the gag and pol genes were found to develop proliferative epidermal lesions, manifested as diffuse epidermal hyperplasia in homozygous transgenic mice and benign papillomas in heterozygous transgenic mice. Nonpapillomatous skin from both homozygotes and heterozygotes expressed viral RNA, and the viral envelope protein gp120 was localized to the suprabasal keratinocyte. Papillomas contained increased amounts of both viral mRNA and envelope glycoprotein. Exposure of transgenic mice to doses of ultraviolet B (UV-B) irradiation that induced cutaneous injury increased viral gene expression and resulted in the development of papillomas within 14-21 days. Cutaneous injury induced by phenol and liquid nitrogen had similar effects. These data support a role for HIV-1 gene products in the pathogenesis of proliferative epidermal disorders associated with HIV-1 infection. Further, they suggest that the process of wound repair increases HIV-1 gene expression in this transgenic mouse model.

Progressive glomerulosclerosis and enhanced renal accumulation of basement membrane components in mice transgenic for human immunodeficiency virus type 1 genes.

Patients infected with human immunodeficiency virus type 1 (HIV-1) develop a renal syndrome characterized by proteinuria, renal failure, and focal segmental glomerulosclerosis. By using a noninfectious HIV-1 DNA construct lacking the gag and pol genes, three transgenic mouse lines have been generated that develop a syndrome remarkably similar to the human disease. In the present study, we have characterized in detail one of these lines, Tg26. In Tg26 mice, proteinuria was detectable at approximately 24 days of age, followed by severe nephrotic syndrome and rapid progression to end-stage renal failure. Renal histology showed focal segmental glomerulosclerosis and microcystic tubular dilatation. Indirect immunofluorescence studies demonstrated increased accumulation of the basement membrane components laminin, collagen type IV, and heparan sulfate proteoglycan. The viral protein Rev was present in sclerotic glomeruli. Northern blot analysis of total renal RNA showed expression of viral genes prior to the appearance of histologic renal disease, with greatly diminished viral gene expression late in the disease course. Kidneys from transgenic mice expressed increased steady-state levels of collagen alpha 1(IV) mRNA when glomerulosclerosis was present. We conclude that the presence of HIV-1 genes is associated with progressive renal dysfunction and glomerulosclerosis in transgenic mice.

HIV-associated nephropathy in transgenic mice expressing HIV-1 genes.

Transgenic mice were produced that bore copies of a defective HIV provirus. The transgenic offspring from three independently derived mouse lines manifested renal disease associated with proteinuria, a high mortality rate, and HIV-specific gene expression in the kidney. An early histopathological lesion in the kidney was focal glomerulosclerosis. Moribund animals had diffuse glomerulosclerosis with prominent microcystic tubular dilatation, tubular epithelial degeneration, and interstitial nephritis. Electron microscopy revealed ultrastructural features consistent with the glomerulosclerosis: effacement of the foot processes of visceral epithelium and an increase in mesangial cell matrix. Transgenic mice variably expressed 6-, 4.3-, and 2-kb HIV-specific RNAs and HIV-related polypeptides in several tissues including kidney. Immunocytostaining revealed the presence of HIV-related protein in the glomeruli of affected animals. Glomerulopathy in these transgenic mice and HIV-associated nephropathy in man have similar features.

Calmodulin-binding drugs affect responses to cytokinin, auxin, and gibberellic Acid.

Trifluoperazine, a phenothiazine tranquilizer, and tetracaine, a local anesthetic, have been found to inhibit a variety of plant hormone responses at concentrations compatible with their known inhibition of Ca(2+)-calmod-ulin-dependent enzyme activities. Among these responses are cytokinin-dependent betacyanin synthesis and increase in fresh weight in Amaranthus tricolor cotyledons, auxin-dependent increase in length of wheat coleoptile segments and gibberellic acid-dependent induction of alpha-amylase synthesis in barley aleurone layers. The reversibility of some of these inhibitory effects has been demonstrated, indicating that, up to a point, a generalized membrane destruction can be ruled out. The evidence, taken in conjunction with numerous examples from the literature showing calcium involvement in the action of all of the plant hormones, support a unifying theory of hormone action.