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Biomedical subjects

K A Moore

Publications and source records attributed to K A Moore.

At least 91 records · Page 5Linked to original sources
PubMed1995

Targeted disruption of the flk2/flt3 gene leads to deficiencies in primitive hematopoietic progenitors.

The flk2 receptor tyrosine kinase has been implicated in hematopoietic development. Mice deficient in flk2 were generated. Mutants developed into healthy adults with normal mature hematopoietic populations. However, they possessed specific deficiencies in primitive B lymphoid progenitors. Bone marrow transplantation experiments revealed a further deficiency in T cell and myeloid reconstitution by mutant stem cells. Mice deficient for both c-kit and flk2 exhibited a more severe phenotype characterized by large overall decreases in hematopoietic cell numbers, further reductions in the relative frequencies of lymphoid progenitors, and a postnatal lethality. Taken together, the data suggest that flk2 plays a role both in multipotent stem cells and in lymphoid differentiation.

Animals↗
PubMed1995

Response of EMIT amphetamine immunoassays to urinary desoxyephedrine following Vicks inhaler use.

The cross-reactivity of l-methamphetamine (l-desoxyephedrine) to the EMIT-d.a.u. class (EC) and EMIT-d.a.u. monoclonal amphetamine/methamphetamine (EM) assays was evaluated in urine specimens collected from six subjects using Vicks inhalers. The subjects were five men and a woman ranging from 27 to 47 years old. Four subjects used the inhaler as recommended by the manufacturer for five consecutive days; two subjects used double this dosage for three consecutive days. All urine voids were collected, totaling 132 specimens. All specimens were analyzed by the EC and EM assays. Specimens yielding a positive response were then analyzed by chiral and achiral gas chromatography/mass spectrometry (GC/MS). No specimen was positive by the EM assay, whereas 17 specimens yielded positive EC results. One subject for form the "as recommended" group had six positive specimens with maximum l-desoxyephedrine of 872 ng/ml. Both subjects using twice the recommended dosage had positive specimens, maximum l-desoxyephedrine of 1,560 ng/ml. No positive specimen contained > 200 ng/ml l-amphetamine.

Administration, Inhalation↗
PubMed1995

Stereoselectivity of the TDxADx/FLx Amphetamine/Methamphetamine II amphetamine/methamphetamine immunoassay--response of urine specimens following nasal inhaler use.

The TDxADx/FLx Amphetamine/Methamphetamine II fluorescence polarization immunoassay (Abbott Diagnostic) for the detection of amphetamine and methamphetamine in urine was evaluated for stereoselectivity and response to specimens collected following as recommended and double the recommended dose use of Vicks Nasal Inhaler. The assay is calibrated with d-amphetamine, at cutoff concentration of 300 ng/mL for a positive response. Cross-reactivity studies demonstrated a positive result with 1000 ng/mL l-amphetamine, 300 ng/mL d-methamphetamine, and approximately 2000 ng/mL desoxyephedrine. A good correlation was observed between urines obtained following ingestion of d-amphetamine simultaneously analyzed by TDxADx/FLx Amphetamine/Methamphetamine II and gas chromatography/mass spectrometry: r2 = 0.954, N = 100. However, urine obtained following ingestion of racemic methamphetamine showed no correlation between TDxADx/FLx Amphetamine/Methamphetamine II and gas chromatography/mass spectrometry results: r2 = 0.420, N = 28. Urines collected following as recommended use for five consecutive days of Vicks Nasal Inhaler containing l-desoxyephedrine did not yield positive TDxADx/FLx Amphetamine/Methamphetamine II results. Only two urines from a subject using twice the recommended inhaler dose yielded positive TDxADx/FLx Amphetamine/Methamphetamine II results. These urines contained 1560 and 1530 ng/mL desoxyephedrine when analyzed by gas chromatography/mass spectrometry. Greater than recommended use of Vicks Nasal Inhaler may yield false positive TDxADx/FLx Amphetamine/Methamphetamine II results for amphetamine use when calibrated at 300 ng/mL d-amphetamine. If calibrated at 1000 ng/mL, d-amphetamine, the TDxADx/FLx Amphetamine/Methamphetamine II is unlikely to yield false positive results for amphetamine, even following excessive inhaler use.

Adult↗
PubMed1995

Intraventricular administration of antibodies to nerve growth factor retards kindling and blocks mossy fiber sprouting in adult rats.

Repeated subconvulsive electrical stimulation of certain areas of the forebrain leads to kindling, a progressive and permanent amplification of evoked epileptiform activity, which is a model for human temporal lobe epilepsy. Recent studies have shown that kindling induces synthesis of nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) but not neurotrophin-3 (NT-3) in the hippocampus and cortex. Kindling also elicits mossy fiber sprouting and functional synaptogenesis in the supragranular layer, the hilus, and the CA3 region of the hippocampus. Intraventricular administration of antibodies to NGF has been shown to effectively block septohippocampal sprouting in the adult rat, and has been reported to retard amygdaloid kindling. In the present study, we have investigated the possible role of NGF in both kindling and kindling-associated sprouting. We have confirmed a kindling-induced sprouting of the mossy fibers into the stratum oriens of the CA3 region of the hippocampus, utilizing a new semiquantitative method of analysis based on Timm staining. Previous studies found no overt signs of hippocampal damage with this kindling paradigm, indicating that the increased Timm staining likely reflects a purely activity-induced sprouting. Intraventricular infusion of affinity-purified anti-NGF IgGs (which cross-react with NT-3 but not BDNF) resulted in both significant retardation of kindling and inhibition of the kindling-induced mossy fiber sprouting. The findings suggest a role for NGF in both these phenomena.

Animals↗
PubMed1994

Elderly outpatients' understanding of a physician-initiated advance directive discussion.

OBJECTIVE: To examine elderly outpatients' understanding of advance directives (ADs), cardiopulmonary resuscitation (CPR), and artificial nutrition and hydration (ANH) with and without the benefit of a physician-initiated discussion. DESIGN: Randomized controlled trial. SETTING: University-affiliated, community-based, urban family practice residency training program. PATIENTS: One hundred patients aged 65 and older, consecutively sampled and randomly assigned to one of two discussion groups. INTERVENTIONS: Physicians' discussions based on a prepared script consisting of AD issues or health promotion issues. MAIN OUTCOME MEASURES: Test of comprehension of AD, CPR, and ANH information, using open-ended and yes-or-no questions. RESULTS: Patients in the AD and health promotion discussion groups showed good basic understanding. Younger and better-educated patients had a better working knowledge of AD-related information. Understanding of ADs was higher when the physician spent more time talking about AD-related issues after the discussion was completed. CONCLUSIONS: Many elderly outpatients have a good basic understanding of ADs, CPR, and ANH, even without explicit explanations from physicians. However, younger, better-educated patients and those who had longer unstructured discussions had greater AD-related knowledge. These factors need to be considered when framing discussions with patients about ADs and life-sustaining treatments.

Advance Directives↗
PubMed1994

Surgical management of aortic dissection in patients with the Marfan syndrome.

BACKGROUND: Aortic dissection is one of the most lethal potential complications in patients with the Marfan syndrome. METHODS AND RESULTS: Among 360 patients undergoing operative treatment of aortic dissection between 1963 and 1992, 40 had the Marfan syndrome. There were 24 men and 16 women with a mean age of 35 +/- 9 years (+/- 1 SD; range, 15 to 54 years). These patients included 16 with acute type A, 2 with acute type B, 18 with chronic type A, and 4 with chronic type B aortic dissections. The aortic arch was involved in 29 cases. Preoperative complications included acute aortic valvular insufficiency in 13 patients, rupture into the pericardial space in 3, and loss of peripheral pulses in 9. The site of primary intimal tear was the ascending aorta in 25 patients, the aortic arch in 2, the descending aorta in 7, and not identified in 6. Operations included ascending aortic and aortic valvular replacement (with or without coronary artery reimplantation) in 22 patients, ascending aortic replacement alone in 5, and descending thoracic aortic replacement in 9. Four operative deaths (10 +/- 5% [+/- 70% confidence limits]) occurred in 3 acute patient-years and 1 chronic type A patient-years. Long-term follow-up (216 patient-years; range, 1 month to 22 years; mean, 5.4 years) revealed 15 late deaths, 7 from late aortic sequelae. The overall actuarial survival estimates were 71 +/- 8%, 54 +/- 10%, and 22 +/- 11% at 5, 10, and 15 years, respectively. Twenty late aortic operations were required in 14 patients. CONCLUSIONS: Despite satisfactory early results, the long-term survival of patients with the Marfan syndrome was suboptimal (albeit similar to those without the Marfan syndrome). Future progress will pivot on reducing the incidence of aortic dissection in these patients with medical therapy and/or earlier surgical intervention and enhanced postoperative serial imaging surveillance of the entire aorta.

Actuarial Analysis↗
PubMed1994

Cardiac transplantation: the Stanford experience in the cyclosporine era.

We analyzed our experience with 496 patients who underwent primary cardiac transplantation since the introduction of cyclosporine immunosuppression (Dec. 16, 1980, to Jan. 7, 1993). There were 388 male and 108 female patients. Mean recipient age was 40 +/- 16 years (range 0.1 to 70 years, median 44 years). Recipient diagnoses included coronary disease in 188, idiopathic cardiomyopathy in 196, viral cardiomyopathy in 35, and congenital heart disease in 28 patients. Donor age was 25 +/- 10 years (range 1 to 53 years, median 24 years). Graft ischemic time was 148 +/- 57 minutes (range 38 to 495 minutes, median 149 minutes). Operative mortality (hospital death) rate was 7.9% +/- 1.3% (70% confidence intervals). Multivariate logistic regression analysis revealed that (higher) pulmonary vascular resistance and gender (female) were the only independent predictors of hospital death (p < 0.05). Actuarial survival estimates for all patients at 1, 5, and 10 years are 82% +/- 1.7% (83% +/- 1.8% adult, 77% +/- 5.2% pediatric), 61% +/- 2.5% (65% +/- 2.5% adult, 64% +/- 6.6% pediatric), and 41% +/- 3.7% (40% +/- 4% adult, 54% +/- 8.6% pediatric), respectively. For 232 patients treated with triple-drug immunosuppression and induction with OKT3 since 1987, survival estimates at 1 and 5 years are 82% +/- 2.6% and 67% +/- 3.7%, respectively. Causes of death for the entire group were rejection in 29 (14% of deaths), infection in 69 (34%), graft coronary disease in 36 (18%), nonspecific graft failure in 6 (3%), malignancy in 19 (10%), stroke in 6 (3%), pulmonary hypertension in 6 (3%), and other causes in 30 (15%) patients. Actuarial freedom from rejection at 3 months, 1 year, and 5 years was 21% +/- 1.9%, 14% +/- 1.7%, and 7.2% +/- 1.5%, respectively (+/- 1 standard error of the mean). Estimates of freedom from rejection-related death at 1, 5, and 10 years were 96% +/- 1%, 93% +/- 1.4%, and 93% +/- 1.4%, respectively. Actuarial freedom from any infection at 3 months and at 1 and 5 years was 40% +/- 2.3%, 27% +/- 2.1%, and 15% +/- 2.0% and from infection-related death, 95% +/- 1.0%, 93% +/- 1.2%, and 85% +/- 1.9%, respectively. Actuarial freedom from (angiographic or autopsy proved) graft coronary artery disease at 1, 5, and 10 years was 95% +/- 1.2%, 73% +/- 2.7%, and 65% +/- 3.6% and from coronary disease-related death or retransplantation 98% +/- 0.7%, 84% +/- 2.2%, and 66% +/- 4.3%, respectively.(ABSTRACT TRUNCATED AT 400 WORDS)

Actuarial Analysis↗
PubMed1993

Change in prescribing patterns of intravenous histamine2-receptor antagonists results in significant cost savings without adversely affecting patient care.

OBJECTIVE: The cooperative efforts and educational activities associated with a major histamine2-receptor antagonist (H2RA) formulary change and the clinical and financial results are described. EVALUATION PROCESS: An extensive financial and clinical evaluation was conducted. Sources included primary literature, reference texts, institution-specific financial data, and reports of other hospitals' experiences. INTERVENTIONS: Through cooperative efforts with key members of the medical staff, several interventions were adopted: maintain only one parenteral H2RA on the formulary; develop guidelines for H2RA use and stress ulcer prophylaxis; investigate a target drug-reminder system to promote oral H2RA use. RESULTS: Within a month after implementing the formulary change and educational process, prescribing of parenteral H2RAs changed from 80 percent ranitidine to 99 percent cimetidine. Monitoring of nonformulary ranitidine use revealed only three cases of possible or probable association of adverse central nervous system effects with cimetidine in an eight-month period. Elevations of theophylline, lidocaine, or phenytoin serum concentrations; or prothrombin time above the therapeutic range during warfarin therapy occurred in only 5 of 142 monitored patients who received concomitant therapy with an H2RA. No change in serum theophylline concentrations above the therapeutic range was noted to the hospital before and after the conversion. Savings have been estimated at $250,000 in the first year and $775,000 over four years, mostly from the conversion from intravenous ranitidine to intravenous cimetidine therapy. CONCLUSIONS: Successful intervention can be accomplished by cooperation between the pharmacy and the medical staff to achieve cost savings without sacrificing the quality of care.

Cimetidine↗
PubMed1993

Randomized, prospective assessment of bioprosthetic valve durability. Hancock versus Carpentier-Edwards valves.

BACKGROUND: Although the major limitation of porcine valves is their finite durability, no controlled clinical data exist regarding the relative durability of the two porcine bioprostheses implanted most commonly today, the Carpentier-Edwards (C-E) and Medtronic Hancock I (H) valves. METHODS AND RESULTS: To assess this question, 174 patients undergoing aortic (AVR) or mitral (MVR) valve replacement with a bioprosthesis between March 1980 and March 1982 were randomized to receive either a C-E or a H valve. There were 102 AVRs (54 C-E and 48 H) and 74 MVRs (39 C-E and 35 H). For both the AVR and MVR cohorts, the average patient age was 58 +/- 14 years (+/- SD). The male/female ratio was 2.2:1 for AVR and 0.57:1 for MVR. Clinical follow-up was undertaken periodically; the most recent follow-up closing interval was July through October 1992, and current follow-up was 96% complete. Cumulative follow-up totaled 1369 patient-years (mean, 7.7 +/- 3.6 years; median, 9.1 years; maximum, 12.0 years). The main focus of this analysis was bioprosthetic durability, using the AATS/STS guidelines defining "Structural Valve Deterioration" (SVD). Multivariate analysis revealed that (younger) age was the only significant (P = .024) independent predictor of SVD. Valve manufacturer (C-E versus H) and valve site (aortic versus mitral) did not emerge as significant independent risk factors for SVD. Actuarial rates (Cutler-Ederer) expressed as percent free of SVD (+/- SEM) at 10 years (n = number of patients remaining at risk) were 71 +/- 7% and 59 +/- 9% for the C-E (n = 26) and H (n = 17) groups, respectively, for the AVR cohort; for the MVR cohort, these estimates were 60 +/- 10% (n = 12) and 72 +/- 10% (n = 11), respectively, but these differences were not statistically significant (P = NS, Lee-Desu). CONCLUSIONS: After 10 years, there was no statistically significant difference in durability or other valve-related complications between the H and C-E aortic or mitral valves. Based on current information, the choice of a porcine bioprosthesis should be based on factors other than durability, including ease of implantation, hemodynamic performance, and cost.

Aortic Valve↗
PubMed1993

Physicians' predictions of elderly outpatients' preferences for life-sustaining treatment.

BACKGROUND: Research has shown that physicians are poor predictors of patients' life-sustaining treatment preferences. Our study examined the association between three aspects of physician experience and their ability to accurately predict patients' preferences for two different life-sustaining treatments in the event of two serious medical conditions. METHODS: Seventeen physicians predicted the treatment preferences of 57 patients and then interviewed patients regarding their actual treatment preferences. Physicians' professional experience, length of their relationship with the patient, and experience with direct feedback were measured to determine the association of these factors with the accuracy of the physicians' predictions. RESULTS: Physicians became more accurate predictors as they interviewed more patients and received direct feedback regarding the accuracy of their predictions (P < .001). Residents were more accurate than faculty in predicting patients' preferences (P < .05). CONCLUSIONS: Increased experience with life-sustaining treatment discussions improved the physicians' abilities to accurately predict patient preferences. Although possibly resulting from small sample size, neither greater professional experience nor longer relationship with a patient improved the accuracy of physicians' predictions. Future research should examine whether discussing end-of-life issues with patients more often makes physicians more sensitive predictors of patients' life-sustaining treatment preferences.

Aged↗
PubMed1992

Stromal support enhances cell-free retroviral vector transduction of human bone marrow long-term culture-initiating cells.

Gene transfer into hematopoietic stem cells by cell-free virions is a goal for gene therapy of hematolymphoid disorders. Because the hematopoietic microenvironment provided by the stroma is required for stem cell maintenance both in vivo and in vitro, we reasoned that cell-free transduction of bone marrow cells (BMC) may be aided by stromal support. We used two high-titer replication-defective retroviral vectors to differentially mark progenitor cells. The transducing vector was shown to be a specific DNA fragment by polymerase chain reaction of colony-forming cells derived from progenitors maintained in long-term culture (LTC). BMC were infected separately by cell-free virions with or without pre-established, irradiated, allogeneic stromal layers, and in the presence or absence of exogenous growth factors (GF). The GF assessed were interleukin-3 (IL-3) and IL-6 in combination, leukemia inhibitory factor (LIF), mast cell growth factor (MGF), and LIF and MGF in combination. In addition, we developed a competitive LTC system to directly assess the effect of infection conditions on the transduction of clonogenic progenitors as reflected by the presence of a predominate provirus after maintenance in the same microenvironment. The results show gene transfer into human LTC-initiating cells by cell-free retroviral vector and a beneficial effect of stromal support allowing a transduction efficiency of 64.6% in contrast to 15.8% without a supporting stromal layer. A high transduction rate was achieved independent of stimulation with exogenous GF. We propose that autologous marrow stromal support during the transduction period may have application in clinical gene therapy protocols.

Base Sequence↗
PubMed1992

Use of cell-free retroviral vector preparations for transduction of cells from the marrow of chronic phase and blast crisis chronic myelogenous leukemia patients and from normal individuals.

Marrow cells were exposed to the LNL6 or G1N safety-modified variants of the N2 retrovirus, which contain the G418 bacterial resistance gene neo. The frequency of acquisition of the G418 resistance phenotype following exposure to LNL6 or G1N was compared among hematopoietic progenitor cells from the marrow of patients with chronic phase chronic myelogenous leukemia (CML), blast crisis CML, or from nonleukemic individuals. Under the conditions of our experiments, the myeloid committed progenitor cells from 3 of 6 nonleukemic individuals, 9 of 18 chronic-phase CML patients, and 2 of 4 blast crisis CML patients acquired resistance to at least 1 mg/ml G418 following incubation with cell-free supernatants from the PA317 LNL6 or PA317 G1N producer cell lines. Ten of the 32 colonies growing up in 0.8 mg/ml G418 from chronic-phase marrow exposed to LNL6 were shown to contain the neo gene by polymerase chain reaction (PCR) assay of DNA. These results were consistent with estimates of the transduction frequency based on acquisition of resistance to G418 as the number of colonies growing under G418 selection was always greater at 0.8 mg/ml G418 than at higher concentrations of G418 (1.0-1.4 mg/ml). The average transduction frequency at each G418 concentration (1.0, 1.2, and 1.4 mg/ml) in cells from blast crisis CML cells ranged from 2 to 14%, as measured by acquisition of G418 resistance. Chronic-phase CML showed slightly lower average frequencies of transduction (0.6-2.8% of the colonies are G418 resistant). The average transduction frequency of cells from nonleukemic marrow was as high as that seen from the marrow of chronic-phase CML individuals.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗
PubMed1992

Consequences of teen-age parenting.

The changing context of teen-age childbearing and current related controversies are reviewed. Recent research about the consequences of teen-age childbearing for the teen-age mother, the father, and for the children born is examined. The article also summarizes current knowledge about the consequences of teen-age childbearing with regard to the mother's educational attainment, marital experience, subsequent fertility behavior, labor force experience and occupational attainment, and experience with poverty and welfare.

Adolescent↗
PubMed1991

Leukemia inhibitory factor improves survival of retroviral vector-infected hematopoietic stem cells in vitro, allowing efficient long-term expression of vector-encoded human adenosine deaminase in vivo.

Low recovery and poor retroviral vector infection efficiency of hematopoietic stem cells has hindered application of gene therapy for disease affecting blood-forming tissues. Developmental restriction (or death) of stem cells during ex vivo infection has contributed to these difficulties. In these studies we report that the cytokine leukemia inhibitory factor (LIF) directly or indirectly supported the survival of hematopoietic stem cells during culture of bone marrow with vector-producing fibroblasts, resulting in efficient recovery of stem cells able to compete for engraftment in irradiated recipient animals. The infection efficiency of hematopoietic stem cells recovered from these cultures was approximately 80%; and all recipients (20/20) of the LIF-treated marrow were stably engrafted with the progeny of provirus-bearing stem cells. Expression of vector-encoded human adenosine deaminase (hADA) was detected in all recipients at levels averaging 15-50% of endogenous murine ADA in all their hematolymphoid tissues. Survival of stem cells in untreated cultures was approximately 10% of that observed from LIF-treated cultures, resulting in poor engraftment of recipient animals with transplanted cells. The infection efficiency of the few stem cells recovered from untreated cultures, however, was high (approximately 80%), suggesting that LIF did not have an effect on infection efficiency per se, but acted at the level of stem cell survival. Consistent with the poor engraftment observed in the control animals, expression of vector-encoded ADA was only approximately 4-20% of the endogenous levels. These results support the postulated role of LIF as a regulator of hematopoiesis and suggest that cytokine stimulation can positively affect inefficient retroviral vector transduction in hematopoietic stem cells.

Adenosine Deaminase↗