ABSTRACT
Phenylethylamine's acute toxic effects in a population of adult (10 to 12 weeks old; â¼30 g) Swiss male albino mice are significantly increased by para-position aromatic ring halogenation. LDLO, LD50, and LD100 values (mg/kg; x ± SEM) for p-F- (116.7 ± 3.3, 136.7 ± 1.7, and 160.0 ± 2.9), p-Br- (126.7 ± 3.3, 145.0 ± 2.9, and 163.3 ± 3.3), p-Cl- (133.3 ± 3.3, 146.7 ± 1.7, and 165.0 ± 2.9), and p-I-PEA (133.3 ± 3.3, 153.3 ± 1.7, and 168.3 ± 1.7), compared to PEA 203.3 ± 3.3, 226.7 ± 4.4, and 258.3 ± 8.8). Like PEA, the difference between LDLO and LD50, and LD50 and LD100 for individual amines were similar and in the range (10 to 20%). Toxicity variation between the various p-halogenatedPEAs also fell within a relatively narrow range (as a group: LDLO 116.7 ± 3.3 to 133.3 ± 3.3, LD50 136.7 ± 1.7 to 153.3 ± 1.7, and LD100 160.0 ± 2.9 to 168.3 ± 1.7 mg/kg). PEA methylation, (exception of its α-methyl derivative), results in relatively modest changes in acute toxicity. LDLO, LD50, and LD100 values (mg/kg; x ± SEM) for N-Me- (176.6 ± 3.3, 200.0 ± 2.9, and 221.7 ± 3.3), p-Me- (183.3 ± 3.3, 206.7 ± 3.3, and 225.0 ± 2.9), o-Me- (210.0 ± 5.8, 233.3 ± 3.3, and 258.3 ± 1.7), and ß-MePEA (220.0 ± 5.8, 243.3 ± 4.4, and 278.3 ± 44). Similar to PEA, and the p-HPEAs, the difference between LDLO and LD50 and LD50 and LD100 values for individual amines fell within a relatively narrow range (10 to 20%). Variation in toxicity among the methylatedPEAs also fell within a limited range (as a group: LDLO 176 ± 3.3 to 220 ± 5.8, LD50 200.0 ± 2.9 to 243.3 ± 4.4 and LD100 221.7 ± 3.3 to 278.3 ± 4.4 mg/kg). With the exception of PEA's methyl derivative (amphetamine) all the amines studied are rapidly metabolized by monoamine oxidase. This pharmacokinetics difference would help to explain the markedly higher amphetamine toxicity [(LDLO, LD50 and LD100 (mg/kg; x ± SEM) of 21.3 ± 0.9, 25.0 ± 0.6, and 29.3 ± 0.7, respectively)].
Subject(s)
Phenethylamines/toxicity , Toxicity Tests, Acute , Animals , Lethal Dose 50 , Male , MiceABSTRACT
The effects of the administration [intraperitoneally, 15 and 75 mg/kg, except α-MePEA (amphetamine, AMPH) at 5 and 10 mg/kg] of ß-phenylethylamine (PEA), its methylated (o-Me-, p-Me-, α-Me-, ß-Me-, N-Me-, p-OMe-, N,N-di-Me-, and 3,4-diOH-N-Me-), para-halogenated (Br-, Cl-, F-, and I-), and other derivatives for example, p-OHPEA (p-tyramine), on Swiss male albino mice caged behavior fall into 3 broad categories. (1) N,N-diMe-, 3,4-diOH-N-Me-, and o-MePEA tend to reduce the behavioral activity, (2) p-OH and p-IPEA were without noticeable effects, and (3) the remaining compounds increased locomotor activity, produced hyperexcitability and fighting, jumping and vocalization, and convulsion in a graded manner (listed in increasing order p-OMe-, ß-Me-, p-Cl-, p-Br-, p-F-, p-Me-, and N-MePEA, PEA itself and α-MePEA). The latter compound (amphetamine) being the most potent among them; equieffective but with lower potency were p-MePEA, N-MePEA, and PEA itself. The effects of PEAs upon group cage behavior were increased by pretreatment with pargyline (1.5 hours; 15 mg/kg) and decreased after reserpine or haloperidol [4 hours and/or 24 hours (2.5 and/or 2.5 mg/kg) and 1 hour (1 mg/kg), respectively], reaching full suppression with the double-dose regimen of reserpine and single dose of haloperidol. As expected, none of these substances by themselves were noticeable changed group mice activity or stereotypic behavior. The effects of test amines and catecholamine-modulating agents on stereotypy were assessed by rating the sequentially occurring behaviors: increased exploratory behavior with increased sniffing; occasional side-to-side head weaving; paw-licking and other grooming; gnawing, fighting and continuous side-to-side head weaving, and periodic episodes of "popcorn" behavior, during which all mice in the cage ran, jumped, and vocalized. In general, rank efficacy in eliciting stereotype aligned with rank efficacy in affecting group cage behavior. Our results show that a number of as yet little studied monomethylated and monohalogenated PEA analogs share a similar behavioral profile with PEA and AMPH. Behavioral changes observed appear to be, at least in part, mediated by catecholaminergic mechanism as they are modulated by drugs known to influence catecholamine activity. PEA analogs provide a large number of clinically useful drugs; whether further studies on these novel amines will lead to the rational design of newer, safer, and effective PEA-class drugs remains to be seen.
Subject(s)
Behavior, Animal/drug effects , Catecholamines/pharmacology , Phenethylamines/pharmacology , Animals , Haloperidol/pharmacology , Male , Mice , Pargyline/pharmacology , Phenethylamines/chemistry , Reserpine/pharmacologyABSTRACT
Administration of ß-phenylethylamine (PEA), the simplest endogenous neuroamine, and various methylated PEA derivatives including α-methyl PEA (amphetamine, AMP) elicits analgesia in mice. Five or 20 min after intraperitoneal PEA injection of as little as 6 mg/kg resulted in an increased latency response time (from 2.4 ± 0.4 to 8.5 ± 2.3 or 7.0 ± 3.0 s, respectively) to the thermal stimulus (hot-plate test), which reached statistical significance at the 15 mg/kg (20 min; 13.1 ± 0.4 s) or 25 mg/kg dose (5 min; 15.3 ± 4.1 s). This PEA effect, was dose-dependent (albeit non-linear: 6, 12, 15, 25, 50 and 100 mg/kg), reached the cut-off time of 45 s at the upper PEA dose (5 min), and it was consistently enhanced by pretreatment with the monoamine oxidase inhibitor pargyline (P). Methylated PEA derivatives (15 and 100 mg/kg dose) produced various degrees of analgesia (in decreasing order p-Me PEA > PEA > N,N-diMe PEA > N-Me PEA) which, likewise to PEA itself, were consistently increased by P and declined over time (mice tested 5, 20 and 60 min after amine injection); small but statistically significant o- and ß-Me PEA antinociceptive effects (5 min) were observed only at the higher dose (in the presence of P for ß-Me PEA). A small analgesic effect was observed after the administration of AMP (5 or 10 mg/kg) which failed, even after P, to reach statistically significance. Independent of the amine and concentration tested, individual compound's antinociceptive properties were reliably increased by P (exception of AMP), decreased by reserpine (R) or haloperidol (H), and remained essentially unchanged after naloxone (N) administration suggesting the involvement of catecholamines, but not opioid peptides, in their observed analgesic effects. Injection of P + N produced results similar to those seen after P alone. Under the experimental conditions described neither P, R, H or N had any effects by themselves. These findings suggest additional understanding of the mechanism of action responsible for the analgesic effects of these amines would be of interest, leading further to controlled studies on their alleged usefulness as weight reducing agents and sport performance enhancers.
Subject(s)
Analgesics/pharmacology , Phenethylamines/pharmacology , Animals , Dose-Response Relationship, Drug , Male , Methylation , MiceABSTRACT
Phenylethylamine and its monomethylated derivatives p-methylphenylethylamine, α-methylphenylethylamine, phenylethylamine itself, N-methylphenylethylamine, o-methylphenylethylamine, and ß-methylphenylethylamine, readily cross the blood-brain barrier showing a brain-uptake index (%) ± SD (water considered 100 %), of 108 ± 11, 98 ± 14, 83 ± 6, 78 ± 11, 62 ± 7 and 56 ± 6, respectively (injection of tritiated water and 100 µg standard amine, which was measured by gas-liquid chromatography). Similar brain-uptake index values (determined by double isotope counting) were obtained for phenylethylamine and α-methylphenylethylamine (amphetamine) after the injection of tritiated water and C(14)-labeled amine (either 3 µg or when added 100 µg standard compound), suggesting that they entered the brain via passive diffusion. Accordingly, both amines distributed rather evenly in the various rat brain areas examined: uptake index (%) ± SD (double isotope counting; non-, and diluted labeled amine) for phenylethylamine (89 ± 8 and 78 ± 7, 83 ± 9 and 86 ± 9, 96 ± 6 and 84 ± 7) and for α-methylphenylethylamine (88 ± 11 and 87 ± 9, 93 ± 14 and 87 ± 11, 97 ± 12 and 87 ± 9) for the cerebellum, frontal cortex, and striatum, respectively. These results will aid a greater understanding of the pharmacological and behavioral effects observed after the administration of phenylethylamine and methylphenylethylamine derivatives.
Subject(s)
Amphetamine/pharmacokinetics , Blood-Brain Barrier/metabolism , Brain/metabolism , Phenethylamines/pharmacokinetics , Animals , Carbon Radioisotopes , Male , Methamphetamine/analogs & derivatives , Methamphetamine/pharmacokinetics , Rats , Rats, Sprague-Dawley , TritiumABSTRACT
Eighteen male cluster headache (CH) inpatients within a CH series participated in this research. Blood samples were drawn from patients at least 6-hour pain-free after the last acute CH episode and then shortly prior (SP), during, and soon after (SA) a new acute CH attack. Three healthy male, age-comparable drug-free volunteers served as controls; 5 samples were obtained from each of these individual over a 24-hour period. Individual patient's methionine-enkephalin (MET) plasma concentration showed significant changes, and in some subjects, dramatic changes, during the different phases of a single CH episode. Peptide levels followed a general pattern of higher plasma concentration SP to an acute CH attack, followed by decreased levels during the attack itself, and falling even further SA the acute episode. Consistently, 16 of the 18 patients tested showed pre-CH peptide levels significantly higher (arbitrarily the authors considered values 20% or more as "significant") than their own values obtained during the acute CH pain phase, with observed differences reaching 80% or more in 7 of these individuals. For about half of these patients, peptide concentration during the acute CH episode was significantly above the control's range (68.2-87.6 pg MET/mL; control's circulating MET concentration remaining essentially unchanged during a 24-hour period). MET levels were further decreased in essentially all of the post-CH samples, with values falling within (n = 6) or even further below than those in the control's range (n = 11). Neither age, time of CH occurrence, nor patient's use of a number of medications known for failing to influence plasma MET degradation kinetics seemed to significantly influence MET levels. These results might help in the biochemical characterization of the actual phases of a CH episode. Developing drugs modulating MET bioavailability could lead to novel antinociceptive agents useful for the treatment of CH's associated pain.
Subject(s)
Cluster Headache/blood , Enkephalin, Methionine/blood , Plasma/metabolism , Adult , Humans , Male , Middle Aged , Time FactorsABSTRACT
Results from a longitudinal study (blood drawn at days 29, 64, 89,124, 142, and 182 of the protocol) shows that the concentration of platelet-poor plasma (PPP) methionine(5)-enkephalin (MET) in healthy, drug-free, white male individuals (n = 5) remains within a relatively narrow range, well within the experimental error of the analytical procedures used. Interindividual differences fail to reach statistical significance [x ± SD and range (MET picograms per mL of PPP) of 91.2 ± 15.1, 67.1-113.5; 69.6 ± 7.5, 66.1-90.1; 76.6 ± 12.6, 58.5-93.1; 86.8 ± 10.9, 76.3-107.4; and 84.5 ± 11.4, 68.9-103.4; for subjects 1-5, respectively]. MET levels were similar to those recorded from single samples obtained from a group of 24 white male, age-comparable, drug-free healthy volunteers [x ± SD and range (picograms of MET per mL of PPP) of 83.3 ± 15.1 and 57.4-119.1]. The controls' range for all the subjects (n = 29) was 57.4-119.1 pgMET/mL PPP. Compared with the controls, individual patients with cluster headache (CH) show a much wider variation in PPP MET levels (blood drawn at different time intervals, at least 10 samples per patient, over a period of 221-298 days), with many (slightly over half) of single values below the controls range; no single MET level was above the controls range [x ± SD and range (picograms of MET per mL of PPP) of 56.4 ± 27.7, 6.1-100.5; 72.6 ± 20.5, 43.0-113.0; 46.0 ± 28.5, 10.0-92.6; 53.6 ± 27.5, 13.0-101.0; 52.0 ± 26.1, 17.5-83.6; 63.5 ± 22.3, 21.7-91.3 for individuals A-F, respectively]. Although interindividual differences within the patients' group were not statistically significant, their peptide levels were significantly lower than those of controls. Neither the presence of unspecified "headaches between clinic visits" and "daily headaches" (patients E and F, respectively), nor the use of a number of drugs known to lack inhibitory activity upon the aminopeptidase-MET degradation reaction, seemed to significantly influence MET concentration. The results could lead to a better understanding of the etiology of the pain associated with CH, with the relative changes in plasma peptide perhaps reflecting the patients' vulnerability to such a condition. Pharmacological modulation of MET function may prove useful in the treatment of CH-associated pain, whether the development of such drugs could find useful pharmacological applications remains to be explored.
Subject(s)
Aminopeptidases/antagonists & inhibitors , Cluster Headache/blood , Enkephalin, Methionine/blood , Pain/blood , Adult , Blood Platelets/metabolism , Case-Control Studies , Humans , Longitudinal Studies , Male , Middle Aged , Pain/etiology , Peptides/blood , Time FactorsABSTRACT
Changes in the levels or biochemistry of cerebrospinal fluid (CSF) neuropeptides with opioid-like properties have been suggested to reflect alterations in specific biological processes. We have determined various kinetic parameters for methionine-enkephalin (MET) degradation by CSF samples from nonneurological patients. Study subjects included 9 males (51-67 years of age) and 5 females (47-61 years of age). Aliquots, removed from an incubation vessel containing buffer, CSF, and peptide [tyr-3',5'-H(N)MET], were analyzed for tyrosine and other degradation products. Essentially all of the labeled tyrosine from the added MET was recovered as free amino acid after 60 minutes of incubation (1:2 ratio, vol:vol; optimum pH 7.4; and temperature 37°C); other possible peptide metabolites (>3%) were not detected. Irrespective of age or gender, the peptide's degradation half-life and initial velocity values were in a limited range; t1/2 26.2 ± 5.5 and 20.8-33.8 minutes, and Iv 0.03 ±0.01 and 0.02-0.03 pg of peptide per milligram protein per minute. Km and Vmax values were 0.19 ± 0.02 and 0.17-0.21 mM, and 9.8 ± 2.2 and 7.6-12.0 µmol·L·min, respectively. Neither CSF sample storage time (up to a year) nor repeated freezing and thawing (up to 3 times over a year) altered the kinetics or products of this reaction. These preliminary findings might serve as reference values when conducting similar studies using CSF from patients diagnosed with specific neurological conditions; significant alterations in MET degradation profile in such a population could provide valuable biological markers for diagnostic and treatment purposes.
Subject(s)
Enkephalin, Methionine/cerebrospinal fluid , Aged , Amino Acids/analysis , Biomarkers , Female , Half-Life , Humans , In Vitro Techniques , Kinetics , Male , Middle Aged , Specimen Handling , Tyrosine/analysisABSTRACT
Current diagnostic criteria for headaches are based on the International Classification for Headache Disorders, second edition, which is largely built on data obtained from clinical examinations and patients' medical histories. Despite decades of vigorous basic and clinical research, we still lack reliable clinical laboratory diagnostic markers for headaches, which clearly obstructs the physician's ability to optimize and follow the patient's response to treatment protocols as well as holds back the discovery and implementation of new therapeutic modalities. In this paper, we review and discuss current efforts to identify and characterize biochemical and immunological changes in biological fluids and tissue that may be specifically associated with the etiology and/or pathophysiology of migraine and cluster headaches; we also discuss some of the recent genetic findings and ion channel modulation studies that may help to distinguish among various headache populations.
ABSTRACT
Orthostatic hypotension (OH) is regarded as a decrease primarily in systolic blood pressure on changing position from supine to erect. Based on clinical criteria, it is characterized by a decrease in systolic pressure of 20 mmHg and diastolic pressure of 10 mmHg within 1 to 3 minutes of standing after being supine. It is most prevalent in, although not limited to, the elderly population and is characterized by a variety of problems, including diminished cognition and disturbed emotion along with gate problems, falls, and brain and cardiovascular difficulties. Although often seen as an age-related condition, occurrence of OH is also associated with a number of autonomic nervous system neurodegenerative disorders. Medications may play a direct role in the risk of triggering OH; these drugs include, but are not limited to, agents used in the treatment of hypertension, myocardial ischemia, psychosis and schizophrenia, depression, Alzheimer and Parkinson disease as well as a vaccine approved for the prevention of cervical cancer. Most of these agents increase the risk for triggering OH through varying vasodilative mechanisms or through sympathetic nervous system interruption; for other drugs, no mechanism of action has been identified. These factors should be considered when diagnosing OH and when prescribing remedies for both patients with OH and those without OH; medication's contributions to the severity and/or risk of developing OH could limit their use. However, their effects could be attenuated or even eliminated by modifying drug dosages.
Subject(s)
Blood Pressure , Hypotension, Orthostatic/etiology , Vasodilation/drug effects , Age Factors , Aged , Blood Pressure/drug effects , Humans , Hypotension, Orthostatic/diagnosis , Hypotension, Orthostatic/physiopathology , Neurodegenerative Diseases/complications , Posture , Risk Factors , Severity of Illness Index , Sympathetic Nervous System/drug effects , Sympathetic Nervous System/metabolismABSTRACT
Select phenothiazine drugs significantly decrease, in a dose-dependent manner, the rate of methione-enkephalin (MET) degradation by discrete human brain areas, for example, putamen and hippocampus. This pentapeptide is rapidly, and essentially completely, hydrolyzed at the tyrosine-glycine bond by bacitracin-sensitive aminopeptidase(s) (AP); neither dipeptidyl peptidase(s) (N-carboxyphenylmethyl leucine and captopril) nor peptidyl dipeptidase(s) (thiorphan) inhibitors altered the kinetics of MET degradation. Half-life (t1/2) and initial velocity (Iv) of this reaction were significantly increased and decreased, respectively, by fluphenazine > prochlorpherazine > chlorpromazine > thioridazine > promethazine > ethopropazine; brain A hippocampus (t1/2, control 2.8 and 60.2, 22.9, 15.4, 10.0, 9.9, and 4.8 minutes; and Iv, control 59.0 and 3.1, 10.7, 21.3, 22.8, 23.8, and 36.9 pg MET/mg brain tissue/minute) and putamen (t1/2, control 2.5 and 52.4, 19.9, 12.4, 8.2, 8.4, and 4.1 minutes; and Iv, control 53.1 and 2.7, 9.3, 17.1, 18.6, 20.1, and 31.7 pg MET/mg brain tissue/minute). Bacitracin was used for comparison purposes; hippocampus (t1/2 and Iv of 64.2 minutes and 4.3 pg MET/mg brain tissue/minute, respectively). Results using brain B tissue followed a comparable pattern, providing similar results. Hippocampus and putamen samples from both brains showed similar Km (mean 25.2, muM; range, 23.3-27.2 mum), Vmax (mean 108 nmol/mg protein/minute; range, 103-115 nmol/mg), and IC50 values (bacitracin, mean 14.4 muM; range, 13.8-14.7 mum) for MET AP degradation. Neither the phenothiazines methotrimeprazine or trifluoperazine nor other commonly used nonphenothiazine antipsychotic tested, for example, clozapine, haloperidol, loxapine, molindone, sulpiride and thiothixine, significantly altered the kinetics of this reaction. The presence of the phenothiazine molecule appears to be necessary for AP inhibition; however, our results failed to show s correlation among chemical structure, pharmacologic profile, and tested compound ability to inhibit MET degradation. This research provides initial information that could lead to the rational design of agents capable of modulate the bioavailability of enkephalins and other AP-metabolized biologically active compounds. Whether their development could find useful pharmacologic applications remains to be explored.
Subject(s)
Aminopeptidases/metabolism , Bacitracin/pharmacology , Enkephalin, Methionine/metabolism , Enzyme Inhibitors/pharmacology , Hippocampus/metabolism , Phenothiazines/pharmacology , Putamen/metabolism , Aged , Aminopeptidases/antagonists & inhibitors , Dose-Response Relationship, Drug , Half-Life , Humans , In Vitro Techniques , Male , Middle Aged , Structure-Activity RelationshipABSTRACT
After 10-minute incubation of [3H]-tyrosine methionine-enkephalin (MET) with 100,000 x g supernatant from select brain regions of patients with chronic schizophrenia (n = 3), essentially all of the labeled tyrosine was recovered as the free amino acid. Initial velocity and half-life of MET degradation obtained from different brain areas (limbic system, thalamus, basal ganglia, cerebellum, and cortex) of individual brains or from equivalent sections from different brains were scattered and considerable spread out (brains A, B, and C: 21.7-60.2 and 2.1-14.3, 25.6-88.7 and 1.6-14.1, 24.5-56.1 and 2.6-14.3 pg MET/mg brain tissue/min and min, respectively; brains A-C range, 21.7-88.7 pg MET/mg brain tissue/min and 1.6-14.3 min, respectively). These results failed to identify consistent differences in peptide degradation kinetics between the various brains areas studied from the same individual or from equivalent section from different subjects. MET metabolic rate was pH and temperature-dependent (optimum 7.4 degrees C and 37 degrees C), reduced by the aminopeptidase inhibitors puromycin, bacitracin, and bestatin, and to a lesser extent by thioridazine. However, peptide metabolism was not significantly affected by differences in tissue storage time or repeated freezing and thawing; by preincubation with N-carboxymethyl phenyl leucine, captopril, or thiorphan (dipeptidyl peptidase[s] or peptidyl dipeptidase[s] inhibitors, respectively); or by the many different drugs used by the patients with chronic schizophrenia. Our findings, although of a preliminary nature and generally similar to those recently reported for comparable studies on nonneuropsychiatric patients, provide a much needed understanding of the mechanisms regulating brain MET metabolism. Whether these results may contribute to the rational design of pharmacologic strategies for the treatment of pathologies associated with alterations in the enkephalinergic system needs further research.
Subject(s)
Brain/metabolism , Enkephalin, Methionine/metabolism , Schizophrenia/metabolism , Aged , Chronic Disease , Half-Life , Humans , Hydrogen-Ion Concentration , Kinetics , Male , TemperatureABSTRACT
Incubation of [3H]-tyrosine methionine5-enkephalin (MET) with human brain preparations (100,000g supernatant; sections of the limbic system, thalamus, basal ganglia, cerebellum, and cortex) results in its rapid and complete degradation; over 95% of the initial labeled tyrosine is recovered as the free aminoacid within 10 min. Results show a considerable range in the peptide initial velocity (Iv) and half-life (t1/2) degradation values obtained from different brain sections of individual brains, either from the same or from different main brain areas. This relatively wide range of values was scattered, failing to identify consistent differences between the various brains areas studied. Differences in brain tissue storage time or repeated sample freezing and thawing failed to alter significantly either of these kinetic parameters of MET metabolism. Peptide degradation rate (optimum pH and temperature of 7.4 and 37 degrees C, respectively) was concentration-dependent inhibited by known aminopeptidase inhibitors (puromycin, bacitracin, and bestatin, and to a lesser extent by thioridazine). However, it was not significantly affected by either N-carboxymethyl phenyl leucine, captopril or thiorphan [dipeptidyl peptidase(s) or peptidyl dipeptidase(s) inhibitors, respectively]. A better understanding of the mechanisms regulating brain MET metabolism may contribute to the rational design of pharmacological strategies based in the modulation of its bioavailability.
Subject(s)
Brain/metabolism , Enkephalin, Methionine/metabolism , Aged , Half-Life , Humans , Kinetics , Male , Middle AgedABSTRACT
BACKGROUND: Little is known about how childhood asthma affects immigrant Hispanic families in the United States. Qualitative research is effective for understanding the social, cultural, functional, and structural aspects of asthma in the family context. Furthermore, such knowledge is necessary to develop culturally appropriate interventions for these families. OBJECTIVES: To describe participants' perceptions of their roles in caring for an asthmatic child, to compare family patterns of caring for an asthmatic child by parents' country of origin, to identify barriers to caring for an asthmatic child, and to evaluate specific coping needs of low-income immigrant Hispanic families caring for an asthmatic child. METHODS: Five focus groups were conducted with low-income, immigrant, Spanish-speaking Hispanic adults caring for an asthmatic child, including community health workers, mothers, fathers, and grandparents, along with women with asthma. Audiotaped focus groups were transcribed verbatim in Spanish, forward translated into English, and back translated into Spanish. Data analysis was performed using qualitative analytic methods. RESULTS: Forty-one participants represented a range of countries of origin. Different themes emerged for community health workers vs parents and grandparents and for women vs men caring for a child with asthma. All the participants reported strong beliefs in using folk medicines. Barriers identified included language, culture, poverty, lack of health insurance, and poor living conditions. CONCLUSIONS: Results highlight the lack of asthma self-management skills, diagnostic uncertainty, and the use of folk medicine as factors that should be taken into consideration when tailoring interventions to improve asthma outcomes in this vulnerable population.
Subject(s)
Adaptation, Psychological , Asthma/psychology , Family/psychology , Hispanic or Latino/ethnology , Asthma/epidemiology , Emigration and Immigration , Female , Humans , MaleABSTRACT
The chemical structure of phenothiazine provides a most valuable molecular template for the development of agents able to interact with a wide variety of biological processes. Synthetic phenothiazines (with aliphatic, methylpiperazine, piperazine-ethanol, piperazine-ethyl, or piperidine side-chain) and/or phenothiazine-derived agents e.g., thioxanthenes, benzepines, imonostilbenes, tricyclic antidepressants, dimetothiazine, and cyproheptadine have been effective in the treatment of a number of medical conditions with widely different etiology. These include various currently clinically used drugs for their significant antihistamic, antipsychotic, anticholinergic (antiparkinson), antipruritic, and/or antiemetic properties. They are also employed, although to a minor extent, as antidepressants, antispasmodics, analgesics, and antiarrhythemics. Some of these agents are also useful as anti-inflammatory, coronary vasodilator, radioprotective, sedative, antitussive, and skeletal muscle-relaxing medication. Still, others show different degrees of effectiveness as antibacterials, anthelmintics, antimalarials, or local anesthetics; a few are valuable in the control of acute migraine attacks and intractable hiccough. Adding to the seemingly ever-expanding therapeutic use of phenothiazine derivatives, a number of "old" and newly synthesized compounds e.g., "half-mustard-type" and benzo[alpha]phenothiazines, appear to be helpful as multidrug resistance modifiers, a property of particular importance in cancer chemotherapy. Some phenothiazines inhibit human plasmatic leucine-enkephalin aminopeptidase(s), enzymes known to regulate the turnover rate of a wide range of bioactive substances. These findings could lead to the design of new therapeutic treatment modalities for conditions such as Alzeimer's and Creutzfeldt-Jakob disease. Hopefully, this work will help to the rational design of new and improved pharmacological approaches based on a better understanding of the correlation between chemical structure, pharmacodynamic properties, and pharmacological activity of various phenothiazines and phenothiazine-derived classes of drugs.
Subject(s)
Antipsychotic Agents/therapeutic use , Phenothiazines/therapeutic use , Animals , Antipsychotic Agents/chemistry , Humans , Phenothiazines/chemistry , Structure-Activity RelationshipABSTRACT
We identified a number of clinically used drugs and biologically active endogenous peptides able to significantly decrease the rate of human plasmatic aminopeptidase (AP) leucine-enkephalin (LEU) degradation. Bacitracin, bestatin, fluvoxamine, and each of 4 peptides tested significantly increased, in a dose-dependent manner (10-10 M), LEU degradation half-life (t1/2) in each of 5 plasma samples studied. Each sample was obtained by pooling equal volume of 6 randomly selected, individual plasmas (4 male and 2 female healthy, drug-free volunteers). Thirty subjects (20 females and 10 males) participated in this study. With the exception of fluvoxamine, this inhibitory effect was lacking in various other commonly used drugs with widely different chemical structures and pharmacological profiles, eg, antidepressants (SSRIs, imipramine-like tricyclics, MAOIs), acute antimigraine agents (triptan class drugs), the nonselective beta-adrenergic antagonist propranolol, and serotonin receptor agonists and antagonists. Agents (concentration 10 M used as illustration), listed in decreasing order of LEU-AP inhibitory activity: substance P > angiotensin III > methionine-enkephalin > angiotensin II > fluvoxamine > bestatin gave t1/2 values (+/- SD) of 39.3 +/- 1.1, 29.4 +/- 0.8, 28.3 +/- 0.8, 27.4 +/- 0.7, 24.5 +/- 1.5, and 23.6 +/- 0.9 minutes, respectively. Control, bacitracin, and fluphenazine (known LEU-AP inhibitors were used for comparison) values of 11.8 +/- 1.0, 31.3 +/- 0.7, and 19.6 +/- 1.0 minutes, respectively. As expected, these drugs significantly decreased the initial velocity of peptide degradation; Iv values (+/- SD) of: 0.17 +/- 0.1 (0.02 +/- 0.01), 0.23 +/- 0.2 (0.02 +/- 0.01), 0.25 +/- 0.2 (0.02 +/- 0.01), 0.26 +/- 0.2 (0.03 +/- 0.01), 0.31 +/- 0.1 (0.03 +/- 0.01), and 0.33 +/- 0.1 (0.03 +/- 0.01), respectively; control, bacitracin, and fluphenazine: 1.10 +/- 0.3 (0.12 +/- 0.03), 0.20 +/- 0.1 (0.02 +/- 0.01), and 0.82 +/- 0.2 (0.08 +/- 0.02) pg LEU/min (pg LEU/mg protein/min), respectively. Results emphasize the selective nature of chemical structures required to significantly inhibit AP activity and provided information that could help the rational design of agents with high specificity in a biologic milieu containing multiple peptidases. In this case, targeted modulation of the bioavailability of LEU and other endogenous AP-degraded hormonal and nonhormonal peptides could be useful in the treatment of the pathophysiology associated with various disease conditions. Whether their development could find useful pharmacological applications remains to be explored.
Subject(s)
Aminopeptidases/antagonists & inhibitors , Enkephalin, Leucine/metabolism , Peptides/pharmacology , Pharmaceutical Preparations , Aminopeptidases/blood , Antidepressive Agents/chemistry , Antidepressive Agents/pharmacology , Dose-Response Relationship, Drug , Enkephalin, Leucine/blood , Female , Half-Life , Humans , Hydrolysis , Illicit Drugs/chemistry , Illicit Drugs/pharmacology , In Vitro Techniques , Male , Peptides/chemistry , Pharmaceutical Preparations/chemistry , Serotonin Receptor Agonists/chemistry , Serotonin Receptor Agonists/pharmacology , Structure-Activity RelationshipABSTRACT
We examined the effect of Salmonella typhi (wild-type Ty2 and mutant strain TYT1231)-infected U937 cells on natural killer cell (NKC) cytotoxicity of peripheral blood mononuclear cells (PBMCs) and highly purified NKC (HPNKCs; CD16(+)/CD56(+) > 95%; the rest corresponding to CD3(+) T cells). We also analyzed the possible role of various protein kinases involved in natural cytotoxicity on these processes. PBMC cytotoxicity against S typhi-infected U937 cells was significantly higher (paired Student t test; P < 0.05) than its lytic effect against noninfected cells (control) at the various effector-to-target cell ratios used (30:1 [24.4 +/- 9.7, 25.1 +/- 11.8, and 17.5 +/- 8.6]; 50:1 [26.6 +/- 9.7, 26.7 +/- 12.8, and 21.2 +/- 7.5] and 70:1 [32.4 +/- 14.4, 30.1 +/- 12.4, and 23.1 +/- 7.2], respectively). PBMC NKC activity seemed to be dependent on such ratios and was similar against both Salmonella strains studied. Approximately half of the individual samples tested (n = 12; 8 male and 4 female subjects of comparable age) showed at least a 20% specific lysis increase against their own control; essentially no changes or smaller increases in NKC activity were observed in all other samples. Similar results were obtained using HPNKCs as effector cells (5:1 ratio [38.9 +/- 12.3, 43.3 +/- 11.2, and 27.5 +/- 4.9] and 10:1 ratio [51.3 +/- 9.1, 46.1 +/- 9.8, and 37.7 +/- 15.5, respectively]). In general, specimens significantly lysed after incubation with PBMCs responded in a similar manner to a challenge with HPNKCs. PBMC and HPNKC cytotoxicity against S typhi wild-type-infected U937 cells was significantly decreased in a dose-dependent manner by the addition of genistein (50-200 micromol) or GFX (0.5-2.0 micromol) to the cytotoxicity assay mixture. NKC activity was almost completely inhibited at the highest genistein and GFX concentrations. In similar experiments, wortmannin (100-500 nmol) failed to inhibit PBMC cytotoxicity and significantly decreased HPNKC activity only at the highest concentration tested. These results show that in the process of NKC recognition and lysis of S typhi-infected U937 cells, there is not a requisite for full bacterial intracellular survival capacity and that S typhi-infected U937 cells are a significantly better target than noninfected U937 cells. NKC signaling pathways activated during the S typhi-infected U937 cell recognition and lysis process are mainly protein tyrosine kinase and protein kinase-C, and they can be blocked by the same protein kinase inhibitors known to inhibit natural cytotoxicity.
Subject(s)
Carrier Proteins/pharmacology , Intracellular Signaling Peptides and Proteins , Killer Cells, Natural/immunology , Leukocytes, Mononuclear/immunology , Salmonella typhi/drug effects , Adult , Female , Humans , Male , Middle Aged , Salmonella typhi/immunology , U937 CellsABSTRACT
A number of drugs with the phenothiazine molecule in their chemical structure inhibit in a dose-dependent manner human plasmatic aminopeptidase leucine(5)-enkephalin (LEU) metabolism. Half-life peptide degradation was significantly increased by thioridazine > fluphenazine > As-1397 [10-(alpha-diethylaminopropionyl)phenothiazine] >/= promethazine >/= chlorpromazine (final drug conc. 10(-4) M); t1/2 (+/- SD) 21.2 +/- 1.1, 19.6 +/- 1.0, 17.2 +/- 0.9, 17.1 +/- 1.0, and 17.1 +/- 1.1 min, respectively. Control and bacitracin (known aminopeptidase inhibitor) values were 11.8 +/- 1.0 and 31.3 +/- 1.7 min, respectively. These drugs significantly decreased (listed in the same order) LEU degradation initial velocity; Iv (+/- SD) 0.77 +/- 0.2, 0.82 +/- 0.2, 0.92 +/- 0.3, 0.93 +/- 0.2, 0.94 +/- 0.3 pg LEU/min, respectively. Control and bacitracin 1.10 +/- 0.3 and 0.20 +/- 0.1 pg LEU/min, respectively. Values represent results from 5 samples, each obtained by pooling 6 individual plasmas (4 male and 2 female; n = 30 healthy, drug-free volunteers). However, neither the phenothiazines ethopropazine, methotrimeprazine, prochlorperazine and trifluoperazine nor the various commonly used heterocyclic antipsychotics tested, e.g., molindone, loxapine, clozapine, haloperidol, sulpiride and thiothixene inhibited plasma LEU degradation kinetics. Our results failed to show correlations between chemical structure, antipsychotic properties and ability to inhibit plasmatic aminopeptidase LEU degradation. Whereas, presence of the phenothiazine molecule appears to be necessary for enzyme inhibition, only five out of nine substituted phenothiazines tested exhibited this effect. Furthermore, there was a lack of correlation between phenothiazines antipsychotic properties and their capacity to inhibit aminopeptidase activity, a property shown by promethazine (antihistaminic) and As-1397 (selective butyrylcholinesterase inhibitor) but lacking in prochlorperazine and trifluoperazine. Our results provide information which could lead to the rational design of agents capable to modulate the bioavailability of enkephalin and other endogenous aminopeptidase-degraded peptides believed to be involved in the etiology and/or pathophysiology associated with various disease conditions. Whether their development could find useful pharmacological applications remains to be explored.
Subject(s)
Antipsychotic Agents/pharmacology , Enkephalin, Leucine/blood , Enkephalin, Methionine/blood , Enzyme Inhibitors/pharmacology , Phenothiazines/pharmacology , Adult , Aminopeptidases/antagonists & inhibitors , Antipsychotic Agents/chemistry , Dose-Response Relationship, Drug , Enkephalin, Leucine/metabolism , Enkephalin, Methionine/metabolism , Enzyme Inhibitors/chemistry , Female , Humans , Hydrolysis , In Vitro Techniques , Male , Middle Aged , Phenothiazines/chemistry , Structure-Activity RelationshipABSTRACT
Peripheral blood mononuclear cell (PBMC) cytotoxicity against S. typhi (wild type or mutant strain TYT1231)-infected U937 cells was significantly higher than its lytic effect against noninfected cells (control) at the various effector-to-target cell ratio used (30:1, 50:1 and 70:1). Natural killer cell activity [expressed as % specific lysis (mean +/- SEM); 30:1 (25.4 +/- 3.6, 25.1 +/- 4.2 and 16.3 +/- 3.3); 50:1 (27.8 +/- 3.7, 26.7 +/- 4.5 and 20.9 +/- 2.9) and 70:1 ratio (33.2 +/- 5.9, 29.4 +/- 4.2 and 22.8 +/- 2.8), respectively] appeared to be dependent on such ratios and independent of the S strain studied. Most (80%) of individual samples tested showed at least a 20% specific lysis increase over their own control; essentially no changes or smaller increases in NKC activity were observed in all other samples. Similar results were obtained when using highly purified NKC (HPNKC) preparations as effector cells [NKC activity (mean +/- SEM); 5:1 (46.2 +/- 4.7, 43.2 +/- 5.0 and 25.2 +/- 2.3) and 10:1 effector-to-target cell ratio (49.3 +/- 4.9, 44.7 +/- 5.2 and 27.2 +/- 2.6, respectively)]. All individual samples tested showed at least a 20% specific lysis increase over their own control. These results show that S. typhi-infected U937 cells are a significantly better target for NKCs than control cells and indicate that intracellular bacteria survival capacity is not a critical factor for infected cells becoming a NKC target.