Treatment and follow-up of venous thrombosis in the neonatal intensive care unit: a retrospective study.

OBJECTIVE: The critically ill, premature patients of neonatal intensive care units are susceptible to venous thrombosis, an adverse event associated with short- and long-term morbidity. Venous thrombosis is frequently treated with low-molecular-weight heparins (LMWHs) such as enoxaparin, but optimal dosing of LMWH must balance the morbidity of venous thrombosis with the potential adverse affects of anticoagulation. The optimal dosing of enoxaparin for premature infants is unclear. The objective of this study was to describe enoxaparin therapy and follow-up in critically ill neonates diagnosed with venous thrombosis. STUDY DESIGN: Retrospective medical record review in the neonatal intensive care unit (NICU) in a single tertiary care institution. Infants with venous thrombosis diagnosed in the NICU were identified using preexisting quality improvement lists and medical records. RESULTS: Twenty-six infants with 30 venous thromboses were identified with a median gestational age of 31 weeks at birth. Eighteen (69%) infants received enoxaparin for venous thrombosis during their hospitalization, beginning with a median dose of 1.5 mg kg-1 every 12 h. This dose was increased to a median of 2.1 mg kg-1 every 12 h to achieve target anti-factor Xa levels. The target dose was significantly higher in patients with a postmenstrual age of <37 weeks. Enoxaparin treatment was documented after discharge in 12 patients, continuing for a median of 99 days. Four patients died during hospitalization and their deaths were not attributable to venous thrombosis or anticoagulation complication. Follow-up documentation between 6 and 24 months after venous thrombosis diagnosis revealed no major morbidity of venous thrombosis or enoxaparin therapy. CONCLUSION: Our data reinforce the relative safety and necessity of enoxaparin doses above 1.5 mg kg-1 per 12 h in most neonates. This was particularly true for infants at lower postmenstrual age.

Ultrastructural analysis of a murine model of congenital hydrocephalus produced by overexpression of transforming growth factor-beta1 in the central nervous system.

The purpose of this study was to elucidate using transmission electron microscopy (TEM) the ultrastructural changes that occur within the cortical gray matter of a novel reproducible model of congenital hydrocephalus in mice created to overexpress the cytokine transforming growth factor-beta1 (TGF-beta1) in the central nervous system. Brain tissue was obtained from mice from a colony engineered to overexpress TGF-beta1 at two days postpartum and compared to a wild-type aged-matched control. This tissue was fixed using a solution containing 1.25% paraformaldehyde and 1.25% glutaraldehyde in phosphate buffer at least 3-4 h and then cut into 40-50 microm sections. Randomly selected thin sections were stained with uranyl acetate and lead citrate, and then analyzed using a JEOL-100CX or 1200EX transmission electron microscope at accelerating voltage 80 kV. Dramatic neuronal and glial pathology was observed throughout the cortical neuropil in TGF-beta1 mice. The most striking change in the hydrocephalic mice was severe edema with extracellular fluid, possibly due to cerebrospinal fluid (CSF) penetration into the cortex. In addition, severe disruption of the cytoplasmic matrix was seen throughout the cortex, with damage to cellular organelles and particularly severe damage to mitochondria. Our results suggest that congenital hydrocephalus may be associated with significant damage to cortical tissue.

p53 represses androgen-induced transactivation of prostate-specific antigen by disrupting hAR amino- to carboxyl-terminal interaction.

Prostate-specific antigen (PSA) is highly overexpressed in prostate cancer. One important regulator of PSA expression is the androgen receptor (AR), the nuclear receptor that mediates the biological actions of androgens. AR is able to up-regulate PSA expression by directly binding and activating the promoter of this gene. We provide evidence here that that this AR activity is repressed by the tumor suppressor protein p53. p53 appears to exert its inhibition of human AR (hAR) by disrupting its amino- to carboxyl-terminal (N-to-C) interaction, which is thought to be responsible for the homodimerization of this receptor. Consistent with this, p53 is also able to block hAR DNA binding in vitro. Our previous data have shown that c-Jun can mediate hAR transactivation, and this appears to result from a positive effect on hAR N-to-C interaction and DNA binding. Interestingly, c-Jun is able to relieve the negative effects of p53 on hAR transactivation, N-to-C interaction, and DNA binding, demonstrating antagonistic activities of these two proteins. Importantly, a p53 mutation found in metastatic prostate cancer severely disrupts the p53 negative activity on hAR, suggesting that the inability of p53 mutants to down-regulate hAR is, in part, responsible for the metastatic phenotype.

A selective peroxisome proliferator-activated receptor delta agonist promotes reverse cholesterol transport.

The peroxisome proliferator-activated receptors (PPARs) are dietary lipid sensors that regulate fatty acid and carbohydrate metabolism. The hypolipidemic effects of the fibrate drugs and the antidiabetic effects of the glitazone drugs in humans are due to activation of the alpha (NR1C1) and gamma (NR1C3) subtypes, respectively. By contrast, the therapeutic potential of the delta (NR1C2) subtype is unknown, due in part to the lack of selective ligands. We have used combinatorial chemistry and structure-based drug design to develop a potent and subtype-selective PPARdelta agonist, GW501516. In macrophages, fibroblasts, and intestinal cells, GW501516 increases expression of the reverse cholesterol transporter ATP-binding cassette A1 and induces apolipoprotein A1-specific cholesterol efflux. When dosed to insulin-resistant middle-aged obese rhesus monkeys, GW501516 causes a dramatic dose-dependent rise in serum high density lipoprotein cholesterol while lowering the levels of small-dense low density lipoprotein, fasting triglycerides, and fasting insulin. Our results suggest that PPARdelta agonists may be effective drugs to increase reverse cholesterol transport and decrease cardiovascular disease associated with the metabolic syndrome X.

The pregnane X receptor: a promiscuous xenobiotic receptor that has diverged during evolution.

Transcription of genes encoding cytochrome P450 3A (CYP3A) monooxygenases is induced by a variety of xenobiotics and natural steroids. There are marked differences in the compounds that induce CYP3A gene expression between species. Recently, the mouse and human pregnane X receptor (PXR) were shown to be activated by compounds that induce CYP3A expression. However, most studies of CYP3A regulation have been performed using rabbit and rat hepatocytes. Here, we report the cloning and characterization of PXR from these two species. PXR is remarkably divergent between species, with the rabbit, rat, and human receptors sharing only approximately 80% amino acid identity in their ligand-binding domains. This sequence divergence is reflected by marked pharmacological differences in PXR activation profiles. For example, the macrolide antibiotic rifampicin, the antidiabetic drug troglitazone, and the hypocholesterolemic drug SR12813 are efficacious activators of the human and rabbit PXR but have little activity on the rat and mouse PXR. Conversely, pregnane 16alpha-carbonitrile is a more potent activator of the rat and mouse PXR than the human and rabbit receptor. The activities of xenobiotics in PXR activation assays correlate well with their ability to induce CYP3A expression in primary hepatocytes. Through the use of a novel scintillation proximity binding assay, we demonstrate that many of the compounds that induce CYP3A expression bind directly to human PXR. These data establish PXR as a promiscuous xenobiotic receptor that has diverged during evolution.

Intermittent subcutaneous injections for symptom control in hospice care: a retrospective investigation.

An alternative route to oral medications used by some hospice programs is intermittent injections of medications using an indwelling subcutaneous butterfly needle. The nurse places the infusion sets and instructs caregivers on medication administration. Although this method has become more common in hospice care, it has not received much attention in part because of a lack of data to support its efficacy. This study describes the use of intermittent subcutaneous medications for symptom relief in a home hospice program. A chart review was conducted of the 191 patients who received medications by this route during three calendar years; 77% had cancer. The average duration of hospice care was 25 days; on average, intermittent subcutaneous medications were instituted 4 days prior to the patient's death. The main indications for this route were inability to swallow/somnolence (65%), and pain unresponsive to oral medication (19%). Symptoms to be controlled by this method were pain (88%), anxiety (72%), and dyspnea (4%). Morphine was used most frequently for pain, and Ativan was used most frequently for anxiety. Side effects from the medications and problems with this route of administration were rarely reported, thereby supporting the practicality of this method in hospice care. These results form the foundation for a prospective study that is documenting staff, patient, and caregiver variables that impact on the effectiveness and manageability of this method of symptom management in hospice care.

Intermittent subcutaneous injections of pain medication: effectiveness, manageability, and satisfaction.

This study describes the use of intermittent subcutaneous injections of medications for pain control in a home hospice program. Six questionnaires were used to collect data over a one-year time period on the 52 patients who received medications by this route. Eighty-four percent of those patients had a diagnosis of cancer; patients received hospice care for a mean of 25 days. On average, intermittent subcutaneous medications were instituted three days prior to the patient's death. The main indication for this route was difficulty swallowing. Morphine was the most frequently used drug; side effects from the medication and problems with the route were rarely reported. Demographic information was collected on both the nursing staff and patients' caregivers; analysis indicated that caregivers were able to manage the injections and were satisfied with the method. Assessment of pain prior to and following the injections demonstrated the effectiveness of this method in controlling patients' pain.

The dihedral symmetry of the p53 tetramerization domain mandates a conformational switch upon DNA binding.

The p53 tumor suppressor forms stable tetramers, whose DNA binding activity is allosterically regulated. The tetramerization domain is contained within the C-terminus (residues 323-355) and its three-dimensional structure exhibits dihedral symmetry, such that a p53 tetramer can be considered a dimer of dimers. Under conditions where monomeric p53 fails to bind DNA, we studied the effects of p53 C-terminal mutations on DNA binding. Residues 322-355 were sufficient to drive DNA binding of p53 as a tetramer. Within this region residues predicted by the three-dimensional structure to stabilize tetramerization, such as Arg337 and Phe341, were critical for DNA binding. Furthermore, substitution of Leu344 caused p53 to dissociate into DNA binding-competent dimers, consistent with the location of this residue at the dimer-dimer interface. The p53 DNA site contains two inverted repeats juxtaposed to a second pair of inverted repeats. Thus, the four repeats exhibit cyclic-translation symmetry and cannot be recognized simultaneously by four dihedrally symmetric p53 DNA binding domains. The discrepancy may be resolved by flexible linkers between the p53 DNA binding and tetramerization domains. When these linkers were deleted p53 exhibited novel DNA binding properties consistent with an inability to recognize four contiguous DNA repeats. Allosteric regulation of p53 DNA binding may involve repositioning the DNA binding domains from a dihedrally symmetric state to a DNA-bound asymmetric state.

Communication, conflict, and psychological distance in nondistressed, clinic, and divorcing couples.

This study compared communication patterns and conflicts over psychological distance in 25 nondistressed couples, 15 clinic couples, and 22 divorcing couples. Data consisted of questionnaire reports completed independently by husbands and wives. The two distressed groups, compared with nondistressed couples, had less mutual constructive communication, more avoidance of communication, more demand/withdraw communication, and more conflict over psychological distance in their relationships. In addition, the divorcing group had less mutual constructive communication than the clinic group and evidenced a trend for more conflict over psychological distance than the clinic group. Consistent with past research, wife demand/husband withdraw communication was more likely across all groups than husband demand/wife withdraw communication. Results are discussed in terms of skills deficits and incompatability models of marital discord.

Tobramycin-adhesive in preventing and treating PTFE vascular graft infections.

UNLABELLED: The present study was designed to determine the effectiveness of N-butyl-2-cyanoacrylate as a vehicle to deliver antibiotics locally to contaminated vascular graft sites and to grafts with established infections. Phase I--Contaminated wound model: Sixteen dogs had a 1-cm section of infrarenal aorta replaced with a PTFE graft. Prior to placement, the graft was immersed in solutions of Escherichia coli 3 X 10(8) CFU/ml and then Staphylococcus aureus 3 X 10(8) CFU/ml. After anastomosis, 1 cc of each solution was placed directly over the graft. Eleven dogs served as controls and 5 as treatment dogs. Parenteral cefonecid was given preoperatively and daily until sacrifice. Treatment animals had the anastomoses and graft sealed with a suspension of N-butyl-2-cyanoacrylate and 1.2 g tobramycin powder (antibiotic glue, ANGL) after contamination. All dogs were reoperated on the third postoperative day. RESULTS: Eleven of 11 control dogs had positive cultures for S. aureus and 9 of 11 had positive cultures for E. coli. Seven of 11 had pseudoaneurysms, 1 exsanguinated. None of the 4 treatment dogs had positive cultures (P = 0.0002), pseudo-aneurysms (P = 0.017), or local signs of sepsis. Phase II--Infected graft model: The 10 surviving infected control dogs served as the established graft infection model. These dogs were randomized into two groups; Group 1 control (N = 5) had the graft replaced; Group 2 treatment (N = 5) had the graft replaced and ANGL treatment. Dogs were sacrificed after 2 weeks. RESULTS: Graft cultures were positive in all 4 control dogs and negative in the 4 treatment dogs (P = 0.005). One dog in each group was eliminated secondary to failure to obtain graft culture. The data show that ANGL can be effective in the prevention and treatment of prosthetic graft infection.

Use of a standard forage to reduce effects of animal variation on estimates of mean voluntary intake.

Sixty test forages (alfalfa, timothy, bromegrass, and orchardgrass mixtures), of differing cuttings and maturities, were harvested as hay in each of 2 yr (30/yr) from three locations. Each of the 60 hays was chopped and fed to four growing sheep to determine voluntary intake. The duration of the trial was 2 yr with five experimental periods per year. In each period, immediately prior to feeding the test forages, intake of the same standard alfalfa hay (standard forage) was measured for every sheep. Use of intake of the standard forage as a covariate reduced mean square error by 38%. Regression of least squares means of intake of the test forages on chemical composition uniformly yielded higher coefficients of determination when means were generated from an analysis of variance that included intake of the standard forage as a covariate. This procedure can be used to increase the accuracy of estimates of mean voluntary intake or to reduce the number of animals needed to attain the same accuracy that would be achieved without use of the covariate.

Prediction of sheep responses by near infrared reflectance spectroscopy.

Prediction of animal response from near infrared reflectance spectra of feeds was compared with predictions from chemical analyses. Sixty samples of pure and mixed forage-based diets were obtained from sheep intake and digestion trials. Sheep responses measured were digestible energy, dry matter intake, and calculated intake of digestible energy. Diets were analyzed chemically for protein, neutral detergent fiber, and in vitro dry matter disappearance. Coefficients of multiple determination and standard errors for fitting the sheep responses to these 60 diverse diets by regression equations developed from chemical analyses (.62 to .70) or spectra (.63 to .72) were similar. The 60 diets were divided into two sets of 30; one set was used to develop calibration equations for each sheep response, and the second set was used to test the equations. Calibration and errors of prediction were similar. When wavelengths chosen for each of the laboratory measurements were used to fit the sheep responses, standard errors were higher than when responses of sheep were predicted directly from spectra. The scanning instrument has the capability of predicting laboratory analyses and shows potential for predicting animal response as accurately as animal response can be predicted from laboratory analyses.

The meadow vole as an experimental animal.

A meadow vole colony has been in operation at The Pennsylvania State University for 6 yr. The breeding colony consists of 16 breeding harems of 1 male and 2-4 females per cage. Over 2,500 weanlings have been available each year for various experiments. Primary emphasis has been directed toward determination of the weanling's nutritional requirements. Adults have been used to study plant factors associated with the palatability of forages. This information has been used to devise specific bioassay procedures to study the relative nutritional value of a wide range of cultivated crop species. Weanlings have been used to evaluate the quantity and quality of protein available for growth from cereal grains and soybeans as well as the energy available for growth from temperate and tropical forages. Studies of antiquality constituents with weanlings have led to the indentification of a toxic constituent in crownvetch forage and the verification of undersirable constituents in raw soybeans and forages. Studies with adults have assisted in clarifying the effects of forage saponins and alkaloids on the paltability response of adult voles. Each of these studies have provided some type of new and useful information that has implications in either nonruminant or ruminant responses to crop plants.