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Biomedical subjects

H Phillips

Publications and source records attributed to H Phillips.

At least 55 records · Page 3Linked to original sources
PubMed1994

Neurotrophin-4/5 is a survival factor for embryonic midbrain dopaminergic neurons in enriched cultures.

Parkinson's disease is a prevalent neurological disease characterized by profound and incapacitating movement disorders. A common pathology in Parkinson's patients is degeneration of substantia nigra dopaminergic neurons that innervate the striatum and a corresponding decrease in striatal dopamine content. We now report that NT-4/5 can prevent the death of rat embryonic substantia nigra dopaminergic neurons in low density, enriched, primary cultures. Furthermore, these neurons express messenger RNA encoding the trkB receptor for NT-4/5 and transcripts for NT-4/5 are present in their environment. In addition, we demonstrate that NT-4/5 protects embryonic dopaminergic neurons from the toxic effects of the neurotoxin MPP+. Thus, NT-4/5 could be a physiological survival factor for midbrain dopaminergic neurons and may be useful as a therapeutic agent for Parkinson's disease.

1-Methyl-4-phenylpyridinium↗
PubMed1993

A cytokine receptor gene cluster in the X-Y pseudoautosomal region?

The receptors for interleukin-3 (IL-3), IL-5, and granulocyte-macrophage colony-stimulating factor (GM-CSF) are heterodimers comprised of ligand specific alpha chains and a common beta chain. The genes encoding the IL-5 receptor alpha chain and the common beta chain reside on chromosome 3 and 22 respectively, while the GM-CSF receptor alpha chain gene (CSF2RA) has been mapped to the pseudoautosomal region (PAR) of the sex chromosomes, which is a 2.6-Mb stretch of homologous sequence at the tips of the short arms within which a single obligatory recombination occurs during male meiosis. We have mapped the gene encoding the IL-3 receptor alpha chain (IL3RA) to the sex chromosomes by polymerase chain reaction (PCR) analysis of human-mouse or human-chinese hamster cell hybrids, and to Yp13.3 and Xp22.3 using fluorescence in situ hybridization. To explore the possibility that IL3RA is located within the pseudoautosomal region we screened the Centre d'Etude du Polymorphisme Humain (CEPH) pedigrees for an informative-restriction fragment-length polymorphism (RFLP) that showed male meiotic recombination. Two informative CEPH pedigrees were identified that displayed this phenomenon, confirming the psuedoautosomal location of IL3RA. Using long-range restriction mapping we have found that IL3RA maps to the same 190-kb restriction fragment as CSF2RA, suggesting that a cytokine receptor gene cluster may reside in the PAR.

Base Sequence↗
PubMed1993

Antitumor response to recombinant murine interferon gamma correlates with enhanced immune function of organ-associated, but not recirculating cytolytic T lymphocytes and macrophages.

The mechanism of therapeutic activity for recombinant murine interferon-gamma (rMu IFN gamma) in the treatment of metastatic disease was investigated by comparing effector cell augmentation with therapeutic activity in mice bearing experimental lung metastases (B16-BL6 melanoma). Effector cell functions in spleen, peripheral blood, and lung (the tumor-bearing organ) were tested after 1 week and 3 weeks of rMu IFN gamma administration (i.v. three times per week). Natural killer (NK), lymphokine-activated killer (LAK), cytolytic T lymphocyte (CTL) activities against specific and nonspecific targets, and macrophage tumoristatic activity were measured. rMu IFN gamma demonstrated immunomodulatory activity in most assays of immune function. The optimal therapeutic protocol of rMu IFN gamma (2.5 x 10(6) U/kg, three times per week) prolonged survival and decreased the number of pulmonary metastatic foci. This therapeutic activity was correlated with specific CTL activity from pulmonary parenchymal mononuclear cells (PPMC), but not from spleen or blood. Macrophage tumoristatic activity in PPMC also correlated with therapeutic activity, but activity in alveolar macrophages did not. However, therapeutic activity did not correlate with NK or LAK activity at any site. These results demonstrate that the optimal therapeutic protocol is the same as the optimal immunomodulatory dose for pulmonary CTL and macrophage activities. Furthermore, while immunological monitoring may help to optimize treatment protocols, current monitoring procedures that use readily accessible sites, particularly peripheral blood, may not accurately predict the therapeutic efficacy of biological response modifiers in clinical trials.

Animals↗
PubMed1993

A comparison of cefpodoxime proxetil and cefaclor in the treatment of acute exacerbation of COPD in adults.

In this multicenter, observer-blinded study, 301 patients with signs and symptoms of acute bacterial exacerbation of COPD were randomized (2:1) to receive either cefpodoxime proxetil (200 mg, bid) or cefaclor (250 mg, tid) for 10 days. Clinical and microbiologic evaluations were performed before treatment, during therapy (study days 3 to 5), at the end of therapy (3 to 7 days posttreatment), and at long-term follow-up (4 weeks posttreatment). The most common pretreatment isolates were Haemophilus influenzae, Haemophilus parainfluenzae, and Streptococcus pneumoniae. Significantly (p < 0.001) more bacterial isolates were susceptible in vitro to cefpodoxime (233 of 256, 91 percent) than to cefaclor (215 of 255, 84 percent). There were no statistically significant differences between the two drug regimens in eradication of the initial pathogen (cefpodoxime, 116 of 128, 91 percent; cefaclor, 59 of 64, 92 percent) or end-of-therapy clinical response (cure + proved; cefpodoxime, 99 of 100, 99 percent; cefaclor, 45 of 49, 92 percent) rates for evaluable patients. Both drug treatments were well-tolerated, with a similar incidence of drug-related adverse events (cefpodoxime 11 percent, cefaclor 12 percent). Cefpodoxime (bid) was as safe and effective as cefaclor (tid) in the treatment of acute exacerbation of COPD. The less frequent dosing regimen of cefpodoxime may improve patient compliance compared to those antibiotics that require three or four daily doses.

Acute Disease↗
PubMed1992

Effect of tumor burden and route of administration on the immunotherapeutic properties of polyinosinic-polycytidylic acid stabilized with poly-L-lysine in carboxymethyl cellulose [Poly(I,C)-LC].

We examined the immunomodulatory and therapeutic activities of poly(I,C)-LC. Mice received a subcutaneous (s.c.) injection of sufficient numbers of MBL-2 lymphoma cells to produce in 1 week either a high or low tumor burden. A week after tumor cell injection, poly(I,C)-LC treatment was initiated; the agent was administered intraperitoneally (i.p.) at 5 mg/kg twice a week or at 2.5 or 0.5 mg/kg every day or as an intravenous (i.v.) injection at 0.5, 0.05, or 0.005 mg/kg three times a week. Poly(I,C)-LC treatment significantly increased antitumor effector cell functions in a variety of organs (including spleen, lungs, and peritoneum), as shown by increased killing of MBL-2 cells in vitro and increased tumor cell killing by natural killer cells and macrophages. Furthermore, prolongation of survival correlated with peritoneal macrophage tumoricidal activity when poly(I,C)-LC was given i.p. and with pulmonary effector cell function (including natural killer, cytolytic T-lymphocyte and macrophage tumoricidal activity) when the agent was administered i.v.

Animals↗
PubMed1992

Bone grafting in primary uncemented total knee arthroplasty.

Forty-two uncemented ICLH and Freeman Samuelson knee replacements that required bone grafting for tibial defects were studied before and after operation. The pattern of bone loss, the techniques of grafting, and the soft tissue releases required are described. Union of the graft was observed in 98% of cases, confirming the value of bone grafting in the reconstruction of the deformed, arthritic knee.

Aged↗
PubMed1992

Assignment of a gene (NEMI) for autosomal dominant nemaline myopathy to chromosome I.

Nemaline myopathy (NEM) is a neuromuscular disorder characterized by the presence, in skeletal muscle, of nemaline rods composed at least in part of alpha-actinin. A candidate gene and linkage approach was used to localize the gene (NEM1) for an autosomal dominant form (MIM 161800) in one large kindred with 10 living affected family members. Markers on chromosome 19 that were linked to the central core disease gene, a marker at the complement 3 locus, and a marker on chromosome 1 at the alpha-actinin locus exclude these three candidate genes. The family was fully informative for APOA2, which is localized to 1q21-q23. NEM1 was assigned to chromosome 1 by close linkage for APOA2, which is localized to 1q21-q23. NEM1 was assigned to chromosome 1 by close linkage to APOA2, with a lod score of 3.8 at a recombination fraction of 0. Recombinants with NGFB (1p13) and AT3 (1q23-25.1) indicate that NEM1 lies between 1p13 and 1q25.1. In total, 47 loci were investigated on chromosomes 1, 2, 4, 5, 7-11, 14, 16, 17, and 19, with no indications of significant linkage other than to markers on chromosome 1.

Actinin↗
PubMed1991

Determinants of the need for early acute intervention in patients treated conservatively after thrombolytic therapy for acute myocardial infarction. TAMI-5 Study Group.

This study sought to determine whether clinical variables can be used to identify patients at high risk of recurrent spontaneous myocardial ischemia or hemodynamic compromise during the 1st 4 days after intravenous thrombolysis for acute myocardial infarction. Of 288 patients randomly assigned to a conservative postthrombolysis strategy, 54 (19%) required urgent cardiac catheterization within 24 h; 75 (26%) underwent urgent cardiac catheterization within 4 days of admission. Of the clinical variables examined by multiple logistic regression analysis, only patient age and anterior wall myocardial infarction correlated with the need for urgent cardiac catheterization (p = 0.0016 and p = 0.017, respectively). Compared with recombinant tissue-type plasminogen activator or urokinase monotherapy, combination therapy with these agents was associated with a lower need for acute intervention during the 1st 24 h after admission, but the difference did not reach statistical significance (14% for combination therapy vs. 21% for each agent alone, p = 0.30). Of the 75 patients undergoing urgent coronary angiography, only 39% had an occluded infarct-related artery. Emergency coronary angioplasty was performed in 49% of the patients and coronary artery bypass graft surgery was performed urgently in 3%. Despite these interventions, the need for urgent cardiac catheterization was associated with an in-hospital mortality rate of 7% (vs. 3% in the group not requiring urgent angiography, p = 0.36); mean left ventricular ejection fraction was 50.5 +/- 11% (vs. 54.3 +/- 10.8%, p = 0.12) and regional infarct zone wall motion was -2.68 +/- 1.07 SD/chord (vs. -2.46 +/- 1.19 SD/chord; p = 0.44).(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon, Coronary↗
PubMed1990

The origin of the Public Health Act of 1919.

South Africa's first national public health measure was passed in 1919, just over 70 years ago. Attempts to enact such legislation in the years immediately after Union had been thwarted by vested interests and it was only the effects of World War I and, more particularly, the dire Spanish influenza epidemic of 1918, which forced Parliament to pass this pioneering measure in June 1919. It remained South Africa's basic public health measure until 1977.

History, 20th Century↗
PubMed1990

Serial evaluation of right ventricular dysfunction associated with acute inferior myocardial infarction.

Right ventricular (RV) function was evaluated serially by multigated blood pool imaging in 18 patients with RV dysfunction associated with acute inferior myocardial infarction. Radionuclide ventriculograms were performed on all patients within 18 hours of chest pain and again at 10 days. In addition, 15 of 18 patients had rest and exercise radionuclide ventriculograms at 3 months. The mean resting right ventricular ejection fractions (RVEF) at admission, 10 days, and 3 months in these patients was 31.8 +/- 12.6% (SD), 46.9 +/- 11.2% (p less than 0.05), and 44.5 +/- 10.2% (p less than 0.05), while the left ventricular ejection fractions were 55.9 +/- 10.6%, 57.9 +/- 13.3%, and 53.1 +/- 11.2% (p = ns). The 3-month exercise radionuclide ventriculogram demonstrated an increase in RVEF greater than 5% in 6 of 15 patients. In eight catheterized patients, neither the location nor the severity of coronary artery narrowing nor the presence of collaterals correlated with the RV exercise response. Improvement in RV function over a 10-day interval following acute inferior myocardial infarction suggests the presence of significant reversible right ventricular dysfunction during the acute phase.

Cardiac Catheterization↗
PubMed1989

Immunomodulatory and therapeutic properties of FK-565 in mice.

The heptanoyl tripeptide, FK-565 is a biological response modifier with potent therapeutic properties for the treatment of experimental and spontaneous metastases. Doses of FK-565 greater than 5 mg/kg are required for in vivo augmentation of natural killer cells, macrophages, and for therapeutic activity, presumably because FK-565 is a peptide small molecular mass which is rapidly degraded and excreted. Optimal therapeutic activity is observed at approximately 25-50 mg/kg FK-565, administered i.v. three times per week for 4 weeks. In addition to its therapeutic properties, which were consistently greater than the positive control at optimal doses, FK-565 had significant immunoaugmentary properties for natural killer cells, macrophages, and T cells both in vitro and in vivo, suggesting that its therapeutic activity is due to immune augmentation.

Adjuvants, Immunologic↗
PubMed1988

Immunomodulatory properties of recombinant murine and human tumor necrosis factor.

Tumor necrosis factor has traditionally been thought to have direct cytostatic and cytotoxic properties with little or no direct immunomodulatory activity. We report here that tumor necrosis factor is able to activate macrophages both in vitro and in vivo and can increase a mixed lymphocyte response and act as an adjuvant for both T- and B-cells in vivo. Adjuvant activity in T-cells occurred in conjunction with the administration of a suboptimal syngeneic tumor cell vaccine. In addition, tumor necrosis factor demonstrated a potent dose-dependent effect on bone marrow stem cell number, dramatically depressing cellularity and thus total stem cell number. An appreciable interval is required for recovery from such stem cell depletion. Therefore, the study of the therapeutic activity of tumor necrosis factor must include a consideration of its immunomodulatory properties.

Adjuvants, Immunologic↗
PubMed1988

Correlation of immunomodulatory and therapeutic activities of interferon and interferon inducers in metastatic disease.

The mechanism of therapeutic activity of recombinant murine interferon-gamma (rMu IFN-gamma) and the IFN inducer polyinosinic-polycytidylic acid solubilized with poly-L-lysine in carboxy methyl cellulose (pICLC) in treating metastatic disease was investigated by comparing effector cell augmentation with therapeutic activity in mice bearing experimental lung metastases (B16-BL6 melanoma). Effector cell functions in spleen, peripheral blood, and lung (the organ with tumor) were tested after 1 and 3 weeks of rMu IFN-gamma or pICLC administration (intravenous, three times a week). In these studies, natural killer (NK), lymphokine-activated killer (LAK), cytolytic T lymphocytes (CTL) (against specific and nonspecific targets), and macrophage tumoricidal and tumoristatic activities were measured. rM IFN-gamma and pICLC had therapeutic activity and immunomodulatory activity in most assays of immune function examined. Specific CTL activity of pulmonary parenchymal mononuclear cells (PPMC), but not in splenocytes or peripheral blood lymphocytes (PBL), during week 3 and not during week 1, correlated with the therapeutic activity of rMu IFN-gamma and of pICLC. Macrophage tumoricidal activity in PPMC, but not in alveolar macrophages, also correlated with the therapeutic activity of rMu IFN-gamma, but the opposite was true for the therapeutic activity of pICLC. NK activity of PPMC, but not of splenocytes or PBL, during week 1 correlated with the therapeutic activity of pICLC; in contrast, NK activity at any site did not correlate with the therapeutic activity of rMu IFN-gamma. LAK activity at any site did not correlate with the therapeutic activity of either agent.

Animals↗
PubMed1988

Bone cement and the liver. A dose-related effect?

The serum liver enzyme levels of 40 consecutive patients before and after cemented hip replacement were compared with a control group having operation without use of cement. Serum gammaglutamyl transferase (SGGT) was abnormally raised, for more than four days, in 12 of the 40 patients (32%) in whom bone cement was used, compared with one of the 36 control patients. The changes in SGGT levels after operation correlated with the weight of cement used (r = 0.66, p less than 0.001), but there was return to normal levels in all patients. A temporary dose-related effect of bone cement on liver function is demonstrated.

Alanine Transaminase↗
PubMed1987

Systematic preclinical study on the therapeutic properties of recombinant human interleukin 2 for the treatment of metastatic disease.

The availability of recombinant human interleukin 2 (rH IL 2) has resulted in its clinical utilization both as a single agent and in combination with lymphokine-activated killer cells. In this report, we discuss the effects of rH IL 2, administered by various routes, on effector cell function, pharmacokinetics and bioavailability, and therapeutic activity. Studies of the pharmacokinetics of in vitro natural killer (NK) cell augmentation by rH IL 2 revealed that a short exposure to high levels of rH IL 2 can augment NK cell activity; however, a prolonged exposure (greater than 12 h) was required to augment NK cell activity at lower doses of rH IL 2. These observations suggested that chronic administration of rH IL 2 might improve immunomodulatory and therapeutic activity. This hypothesis was supported by the results of studies in which we treated experimental and spontaneous metastasis, which revealed that the daily i.p. administration of rH IL 2 resulted in significantly greater therapeutic activity than administration three times/week. The therapeutic protocol for daily i.p. administration had a biphasic dosage optimum, such that low dose therapeutic activity was observed at approximately 100-1000 units/animal in the treatment of experimental metastases or 10 to 100 units/animal in the treatment of spontaneous metastases. There was a second dosage optimum at greater than or equal to 100,000 units/animal rH IL 2 delivered i.p. on a daily basis. Intermediate doses had no significant therapeutic activity. Additional studies revealed that low dose therapeutic activity was not observed in nude mice. In contrast, therapeutic activity was observed in nude mice at high doses of rH IL 2 suggesting that low dose activity was associated with a T-cell-mediated effect, whereas high dose activity may have been mediated by NK or lymphokine-activated killer-like cells. This observation was in agreement with the dose response for T-cell adjuvant activity supporting the hypothesis that low dose therapeutic activity was T-cell associated, because adjuvant activity was observed when rH IL 2 was given daily at approximately 100 units/animal for 3 days, and higher doses had no activity or had a suppressive effect. Because we were concerned about the pharmacological aspects of rH IL 2 treatment, we also examined its therapeutic properties after continuous administration i.p. by osmotic pumps. Under these conditions, therapeutic activity was observed after administration of 600 units/h, whereas lower or higher doses did not have significant therapeutic activity.

Adjuvants, Immunologic↗
PubMed1987

Immunomodulatory and immunotherapeutic properties of recombinant gamma-interferon and recombinant tumor necrosis factor in mice.

These studies were designed to examine the immunodulatory and immunotherapeutic properties of recombinant murine interferon gamma (rM IFN-gamma) and recombinant human tumor necrosis factor (rH TNF). We report that rM IFN-gamma activated murine natural killer cells and macrophages in a dose-dependent manner in vivo. The rM IFN-gamma, which demonstrated a bell-shaped therapeutic response curve, must be administered at specific doses and schedules to produce optimal therapeutic activity. Optimal activity was observed after i.v. administration of 50,000 U/animal rM IFN-gamma three times per week. In contrast, rH TNF produced its major therapeutic activity in the treatment of metastatic disease after i.v. but not i.p. administration. The therapeutic effects of rH TNF were as great in these in vivo systems as those of rM IFN-gamma. Furthermore, rH TNF had additive therapeutic activity when administered in conjunction with suboptimal doses of rM IFN-gamma. Unlike rM IFN-gamma, rH TNF did not activate natural killer cells in vivo or in vitro but did augment in vivo and in vitro macrophage tumoricidal activity. It also had synergistic cytostatic properties with rM IFN-gamma for some murine tumor cell lines in vitro. High levels of rH TNF were readily detected in the serum with a half-life of approximately 30 min after i.v. administration. In contrast, only minimal serum TNF activity occurred after i.p. administration, suggesting that i.v. administration may more efficiently facilitate systemic therapeutic activity. In summary, rH TNF and rM IFN-gamma have therapeutic activity for metastatic disease as individual agents and additive therapeutic activity when used in combination. Furthermore, it appears that in addition to therapeutic potential as cytostatic agents, the immunomodulatory properties of rH TNF have a role in its therapeutic properties.

Animals↗