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Biomedical subjects

R Hines

Publications and source records attributed to R Hines.

At least 19 recordsLinked to original sources
PubMed2001

DH82 cells: a macrophage cell line for the replication and study of equine infectious anemia virus.

In vivo, tissue macrophages have been implicated as an important cell for the replication of equine infectious anemia virus (EIAV). Laboratory investigations of EIAV/macrophage interactions, however, have been hampered by the laborious blood monocyte isolation procedures. In addition, adherent equine macrophage cultures generally have poor long-term viability and are resistant to transfection. This report describes an adherent canine macrophage-like cell line, DH82, that supports the replication of EIAV. This cell line was easily transfectable and supported EIAV Tat transactivation of the LTR. Electrophoretic mobility shift assays were carried out to determine which transcription factor binding sites within the LTR enhancer region were bound by DH82 nuclear extracts. It was found that five different motifs were occupied. The ets motifs that are bound by PU.1 in primary macrophage nuclear extracts specifically interacted with DH82 nuclear extracts. In addition, the PEA-2, Lvb and Oct motifs that are occupied by fibroblast nuclear extracts were also bound by DH82 nuclear extracts. Finally, the methylation-dependent binding protein (MDBP) site that is bound by all nuclear extracts investigated to date demonstrated specific interactions with DH82 nuclear extracts. The observation that both macrophage-specific and fibroblast-specific motifs were utilized by DH82 nuclear extracts suggested that both macrophage-adapted and fibroblast-adapted EIAV could replicate in DH82 cells. Indeed, infectivity studies demonstrated that strains of virus that exclusively replicate in macrophages can replicate in DH82 cells and fibroblast-adapted strains of virus can also replicate in these cells. Finally, these cells could be transfected readily with the EIAV molecular clone, pSPeiav19-2, and virus spread was detected within the culture. In conclusion, this study has identified a useful cell line that should facilitate the study of EIAV expression and replication.

Animals↗
PubMed2000

Cell specificity of the transcription-factor repertoire used by a lentivirus: motifs important for expression of equine infectious anemia virus in nonmonocytic cells.

The equine infectious anemia virus (EIAV) long-terminal repeat (LTR) has been identified as highly variable, both in infected horses and in cell culture. This nucleotide hypervariation is localized to the LTR enhancer region. The EIAV LTR has been implicated in controlling both the cell tropism and virulence of the virus and it is postulated that the enhancer-region hypervariation may be responsible for the LTR effects. Our previous studies have demonstrated that the presence of DNA motifs bound by the ets transcription-factor family member PU.1 are critically important for EIAV expression in equine macrophages. Here we identify and characterize the EIAV LTR enhancer motifs PEA-2, Lvb, Oct, and CRE, that bind to fibroblast nuclear extracts. Three of these four motifs, PEA-2, Oct, and CRE, were determined to be important for expression of the LTR in a fibroblast cell line that supports productive infection of EIAV. These motifs that are important for expression of the LTR in fibroblasts were found to be interdigitated between the PU.1 sites. We hypothesize that the combination of motif interdigitation and cell-specific usage of these motifs may be responsible for the observed EIAV LTR enhancer-region hypervariation.

Animals↗
PubMed1998

Correlation of polyamine and growth responses to N1,N11-diethylnorspermine in primary fetal fibroblasts derived from transgenic mice overexpressing spermidine/spermine N1-acetyltransferase.

A recently generated transgenic mouse line having activated polyamine catabolism due to systemic overexpression of spermidine/spermine N1-acetyltransferase (SSAT) was used to isolate primary fetal fibroblasts as a means to further elucidate the cellular consequences of activated polyamine catabolism. Basal levels of SSAT activity and steady-state mRNA in the transgenic fibroblasts were about approximately 20- and approximately 40-fold higher than in non-transgenic fibroblasts. Consistent with activated polyamine catabolism, there was an overaccumulation of putrescine and N1-acetylspermidine and a decrease in spermidine and spermine pools. Treatment with the polyamine analogue N1,N11-diethylnorspermine (DENSPM) increased SSAT activity in the transgenic fibroblasts approximately 380-fold, whereas mRNA increased only approximately 3-fold, indicating post-mRNA regulation. SSAT activity in the nontransgenic fibroblasts increased approximately 200-fold. By Western blot, enzyme protein was found to increase approximately 46 times higher in the treated transgenic fibroblasts than non-transgenic fibroblasts: a value comparable to 36-fold differential in enzyme activity. With DENSPM treatment, spermidine pools were more rapidly depleted in the transgenic fibroblasts than in nontransgenic fibroblasts. Similarly, transgenic fibroblasts were much more sensitive to DENSPM-induced growth inhibition. This was not diminished by co-treatment with an inhibitor of polyamine oxidase, suggesting that growth inhibition was due to polyamine depletion per se as opposed to oxidative stress. Since the two fibroblasts were genetically identical except for the transgene, the various metabolic and growth response differences are directly attributable to overexpression of SSAT.

Acetyltransferases↗
PubMed1998

Intentional and unintentional injury in the State of Nevada: 1989-1992.

INTRODUCTION: Data from a large population-based trauma registry were used to assess risk factors and outcomes associated with injuries that were either caused unintentionally, were self-inflicted, or resulted from an assault. DESIGN: A retrospective analysis was conducted of all cases of serious trauma (N = 19,505) occurring in the State of Nevada during the 4-year period from January 1, 1989, through December 31, 1992. The outcome measures of interest were Injury Severity Score, hospitalization, and mortality. RESULTS: Of all patients with unintentional injuries, 9.9% died compared with 44.8% of those whose injuries were intentionally caused. Nearly half (49.0%) of all deaths occurred in persons who were intentionally injured. Of the intentional injuries, 70% were from assaults. Self-inflicted injuries accounted for 5.2% of all injuries but 28.2% of the deaths in the registry. Firearms were most often used in both assaults (38.8%) and self-inflicted injuries (87.4%). Logistic regressions showed that, compared with unintentional injuries, assaults were more likely to occur in urban counties, among males, African Americans, and young adults. Also, compared with unintentional injuries, self-inflicted injuries were more likely to occur in urban counties, among Caucasian, and the 65+ age group. CONCLUSION: Although the overwhelming number of injuries in the registry were unintentionally caused, deaths from intentionally caused injuries accounted for almost half of all deaths. The data from Nevada's registry provided the ability to identify who is at risk for trauma-related injury and death. Prevention programs should be designed to target these populations. As prevention programs are implemented, trauma registries such as Nevada's will provide a sound source of data for assessing long-term trends in injury patterns.

Adolescent↗
PubMed1996

Ovulation induction in clomiphene-resistant anovulatory women with normal dehydroepiandrosterone sulfate levels: beneficial effects of the addition of dexamethasone during the follicular phase.

OBJECTIVE: To evaluate the effect on ovulation of a 10-day course of dexamethasone (DEX) initiated concurrently with a 5-day course of clomiphene citrate (CC) in CC-resistant patients with normal DHEAS levels. DESIGN: Retrospective review. SETTINGS: Patients from the clinical practice of the authors at the Medical College of Georgia, Augusta, Georgia. PATIENTS: Thirteen oligomenorrheic women with normal DHEAS levels who failed to ovulate on a graduated regimen of CC up to a dose of 150 mg for 5 days. INTERVENTIONS: Ten-day course of DEX initiated concurrently with a 5-day course of CC; ovulation and pregnancy outcomes recorded. MAIN OUTCOME MEASURE: Pregnancy. RESULTS: Eleven of 13 women had evidence of ovulation. Five clinical pregnancies were achieved. CONCLUSION: These initial data support improvements in follicular development with an overlapping follicular phase regimen of CC and DEX in patients with normal DHEAS levels and a previous poor response.

Adult↗
PubMed1995

Nitroprusside inhibition of platelet function is transient and reversible by catecholamine priming.

BACKGROUND: The time course and reversibility of sodium nitroprusside's in vivo inhibition of platelet function are unclear. METHODS: Platelet aggregation and P-selectin expression as measures of platelet dense and alpha-granule release, respectively, were examined before and after administration of sodium nitroprusside (18 mg) to human volunteers and in in vitro studies. Hypotension occurring with sodium nitroprusside administration was treated with intravenous crystalloid and/or phenylephrine. RESULTS: Compared with preinfusion studies, platelet aggregation to epinephrine was significantly inhibited immediately and 4 min after discontinuation of the sodium nitroprusside infusion but returned to baseline at 8 and 12 min after discontinuing sodium nitroprusside. However, both dense and alpha-granule release to adenosine diphosphate after in vivo sodium nitroprusside were never significantly inhibited even at the time when sodium nitroprusside infusion was maximal. In contrast to our in vivo findings, in vitro incubation of platelet-rich plasma with sodium nitroprusside resulted in significant inhibition of dense and alpha-granule release to adenosine diphosphate. These in vitro inhibitory effects of sodium nitroprusside were reversed by pretreatment with epinephrine but not phenylephrine. CONCLUSIONS: In normal volunteers, sodium nitroprusside inhibits platelet aggregation to epinephrine but not adenosine diphosphate; inhibition was reversed within 8-12 min after discontinuing sodium nitroprusside. Sodium nitroprusside in vitro inhibition of platelet function to adenosine diphosphate was reversed by epinephrine pretreatment. Because of the rapid reversibility of its antiplatelet effect, sodium nitroprusside may be clinically useful even when there is the potential for impaired coagulation.

Adenosine Diphosphate↗
PubMed1994

Treatment of postoperative hypertension after coronary artery bypass surgery. Double-blind comparison of intravenous isradipine and sodium nitroprusside.

BACKGROUND: Hypertension commonly occurs after cardiac surgery and requires therapy to prevent the potentially deleterious effects. METHODS AND RESULTS: After coronary artery bypass graft surgery (CABG), 177 patients with elevated blood pressure > or = 90 mm Hg during the initial 6-hour postsurgical period were selected for this random blinded, parallel study to receive intravenous infusions of either isradipine (n = 90) or sodium nitroprusside (n = 87). Isradipine produced a statistically significant decrease in mean arterial pressure (MAP, delta-23 mmHg) during a 90-minute treatment period. Target MAP (< or = 85 mmHg or a decrease of 10 mmHg, if baseline MAP was between 90 and 95 mmHg) was achieved in 94% of patients 30 minutes after initiation of isradipine infusion (total mean dose, 411 micrograms); target MAP was achieved in 75% of nitroprusside-treated patients (total mean dose, 1708 micrograms). The mean time to control MAP was 18 minutes for isradipine compared with 24 minutes for nitroprusside. Global smoothness in MAP control was graded on a scale of 0 (not controlled) to 5 (excellent). Approximately 76% of isradipine-treated patients received a rating of > or = 3 (mean score, 3.5); 40% of the sodium nitroprusside-treated patients achieved a score of > or = 3 (mean score, 2.0). Both isradipine and nitroprusside produced statistically significant reductions in systolic and diastolic blood pressures, a decrease in systemic vascular resistance, and increases in heart rate, cardiac index, and stroke volume index. Isradipine produced no significant decreases in pulmonary artery occlusion wedge pressure compared with nitroprusside. CONCLUSIONS: Intravenous isradipine was effective and well tolerated in patients with hypertension after CABG and offers an additional therapeutic option to treat patients after cardiac surgery.

Coronary Artery Bypass↗
PubMed1994

Creating an agenda for research and evaluation: HIV service delivery, the Ryan White CARE Act, and beyond.

HRSA, AHCPR and NCAP convened a working meeting in November 1992, to discuss creation of a national agenda for research and evaluation on HIV service delivery systems that are cost-effective, responsive to the needs of the diverse populations affected by the epidemic, and reflective of the lessons learned so far. In this article, the interests and goals of the conveners are described, the meeting's process and outcomes are discussed, and the nine key study areas that were identified and chosen by the meeting participants are presented. It is hoped that this article will stimulate further interest among private and public funders and among the research community in fostering the implementation of HIV service delivery-related research and evaluation studies. If this is accomplished, decision-makers will be better enabled to make informed and responsive policy decisions.

Delivery of Health Care↗
PubMed1993

Transesophageal two-dimensional echocardiographic analysis of right ventricular systolic performance indices during coronary artery bypass grafting.

Sixteen patients (aged 59 +/- 14 years) undergoing coronary artery bypass surgery were evaluated to delineate the intraoperative course of transesophageal echocardiographic right ventricular (RV) systolic performance indices. Pre-induction data included thermodilution RV ejection fraction (RVEFTD), 0.43 +/- 0.13, RV end-diastolic volume index (EDVI), 110 +/- 33 mL/m2, cardiac index (CI), 3.4 +/- 1.0 L/min/m2, RV end-diastolic pressure (EDP), 7.1 +/- 4.2 mmHg, and mean pulmonary artery pressure (PAP), 21 +/- 6 mmHg. Eleven patients had significant right coronary artery (RCA) disease (> 70% occlusion). Five patients arrived with an ongoing nitroglycerin infusion (1 to 3 micrograms/kg/min), which was maintained intraoperatively. Echocardiographic measurements included longitudinal-axis (LA) and short-axis (SA) planimetered area excursion fractions (2DLA and 2DSA, respectively) and LA maximal major and minor axis shortening fractions (max majorLA and max minorLA, respectively). Hemodynamic measurements included RVEFTD, EDVI, CI, EDP, and PAP. Measurements were determined following induction/endotracheal intubation, following sternotomy/pericardiotomy, and after cardiopulmonary bypass (CPB) with the chest open. All patients were maintained on vasodilator therapy post-CPB (nitroglycerin, 1 to 3 micrograms/kg/min [N = 16] and nitroprusside, 0.5 to 4.5 microgram/kg/min [N = 4]) post-CPB. Two patients received inotropic support (epinephrine, 0.2 to 0.3 microgram/kg/min). CPB was associated with significant decreases in max major axisLA and 2DLA (P < 0.05) as compared to measurements determined prior to CPB. Maximum major axisLA values pre-CPB were 0.35 +/- 0.06 and 0.33 +/- 0.08 versus post-CPB values of 0.24 +/- 0.08.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗
PubMed1993

Childhood psychological trauma and chronic refractory low-back pain.

OBJECTIVE: To examine the correlation between childhood psychological trauma(s) and refractory back pain in patients with and patients without prior spine surgery. DESIGN: Retrospective chart review survey of 101 consecutive patients who had undergone multidisciplinary evaluation for refractory back pain. SETTING: Private practice, tertiary care spine center. MAIN OUTCOME MEASURES: Each psychological risk factor (physical abuse, sexual abuse, emotional neglect or abuse, abandonment, and chemically dependent caregiver) was rated as present or absent. Spinal pathology was graded as significant or not significant. RESULTS: There were 56 patients with failed back surgery syndrome, 28 men and 28 women, with a mean age of 43 and mean pain duration of 45 months. There were 45 patients with no prior surgery, 26 men and 19 women, with a mean age of 43 and mean pain duration of 33 months. In the failed back surgery syndrome group, 27 (48%) had three or more risks and 39 (70%) had two or more. When the 12 patients with significant pathology are not considered, 24 of the remaining 44 (55%) patients had three or more risks. In the group with no prior surgery, 26 (58%) had three or more risks and 38 (84%) had two or more. When the five patients with significant pathology are not considered, 24 (60%) had three or more risks. CONCLUSIONS: Multiple childhood psychological traumas may predispose a person to chronic low back pain. In patients in this setting with refractory low back pain with or without prior lumbar spine surgery, three or more childhood psychological risk factors are prevalent, especially in patients with minimal structural pathology.

Adult↗
PubMed1992

Cardiopulmonary bypass induces leukocyte-platelet adhesion.

Cardiopulmonary bypass (CPB) has been demonstrated to activate platelets, producing an increased number of circulating platelets that have undergone alpha-granule release and express granule membrane protein-140 (GMP-140) on their surface. In vitro, GMP-140 mediates activated platelet adhesion to neutrophils (PMN) and monocytes, causing the formation of leukocyte-platelet conjugates. Using a newly developed assay that measures the percentage of circulating leukocyte-platelet conjugates in whole blood, we studied 17 patients undergoing CPB and have determined that (1) monocyte-platelet conjugates increased significantly during CPB, from 18% +/- 1.5% to 44% +/- 4.5% (mean +/- SEM) by the end of CPB, while PMN-platelet conjugates increased only slightly and lymphocyte-platelet conjugates decreased; (2) the time course of the increase in monocyte- and PMN-platelet conjugates paralleled that of the increase in circulating activated platelets, as determined by the presence of surface GMP-140; and (3) monocyte activation, as assessed by increased surface expression of CD11b, showed a gradual increase similar to the increase in monocyte-platelet conjugates, while PMN surface CD11b peaked immediately after the start of CPB. We conclude that CPB, through increased platelet GMP-140 expression, causes formation of monocyte-platelet, and to a lesser extent, PMN-platelet conjugates. The activation of monocytes and PMN on CPB, as evidenced by CD11b expression, occurs with differing time courses.

Blood Platelets↗
PubMed1992

Thermodilution right ventricular ejection fraction measurement reproducibility--a study in patients undergoing coronary artery bypass graft surgery.

OBJECTIVE: To assess the effects of heart rate, right ventricular systolic performance (ejection fraction), chamber dimensions, and flow rate (cardiac index) on the reproducibility of algorithm-derived triplicate thermodilution right ventricular ejection fraction measurements. DESIGN: Prospective study; combined hemodynamic and echocardiographic clinical evaluation. SETTING: Operating room in a university hospital. PATIENTS: Twenty-one coronary artery bypass graft patients. MEASUREMENTS AND MAIN RESULTS: The right atrial delivery site was positioned by analysis of transduced pressure waveform and echocardiographic imaging of tracer agitated saline cavitations. Measurement reproducibility was quantified by determining the variation (standard deviation) within 101 triplicate thermodilution measurement sets. There was no significant relationship between measurement reproducibility and estimates of right atrial area (21.6 +/- 6.9 cm2), diameter (5.1 +/- 0.8 cm) and supero-inferior length (5.1 +/- 0.9 cm) and right ventricular maximal minor axis diastolic diameter (4.21 +/- 1.05 cm). Reproducibility was also unrelated to right ventricular end-diastolic volume index (97.9 +/- 32.7 mL/m2) and cardiac index (2.9 +/- 0.9 L/min/m2). Measurement reproducibility was directly related to mean right ventricular ejection fraction (0.39 +/- 0.14) and inversely related to heart rate (80.8 +/- 18.6 beats/min) (p < .01 and < .001, respectively). CONCLUSIONS: Thermodilution-derived right ventricular ejection fraction measurement reproducibility was unrelated to estimates of right atrial and ventricular dimensions and cardiac index. Measurement reproducibility was a direct function of right ventricular systolic performance and an indirect function of heart rate. Measurement should be interpreted with these constraints in mind.

Adult↗