DNA immunization: a novel approach to allergen-specific immunotherapy.
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Allergens↗
Biomedical subjects
M Roman
Publications and source records attributed to M Roman.
Immunostimulatory DNA sequences necessary for effective intradermal gene immunization.
Vaccination with naked DNA elicits cellular and humoral immune responses that have a T helper cell type 1 bias. However, plasmid vectors expressing large amounts of gene product do not necessarily induce immune responses to the encoded antigens. Instead, the immunogenicity of plasmid DNA (pDNA) requires short immunostimulatory DNA sequences (ISS) that contain a CpG dinucleotide in a particular base context. Human monocytes transfected with pDNA or double-stranded oligonucleotides containing the ISS, but not those transfected with ISS-deficient pDNA or oligonucleotides, transcribed large amounts of interferon-alpha, interferon-beta, and interleukin-12. Although ISS are necessary for gene vaccination, they down-regulate gene expression and thus may interfere with gene replacement therapy by inducing proinflammatory cytokines.
Amino Acid Sequence↗
Preferential induction of a Th1 immune response and inhibition of specific IgE antibody formation by plasmid DNA immunization.
We compared the antigen-specific antibody isotypes and lymphokine secretion by CD4+ T cells in BALB/c mice immunized intradermally with either Escherichia coli beta-galactosidase (beta-gal) or plasmid DNA (pDNA) encoding beta-gal in a cytomegalovirus-based expression vector (pCMV-LacZ). pCMV-LacZ induced mainly IgG2a, whereas beta-gal in saline or alum induced IgG1 and IgE beta-gal-specific antibodies. In addition, splenic CD4+ T helper (Th) cells isolated from pDNA-immunized mice secreted interferon-gamma but not interleukin (IL)-4 and IL-5, whereas Th cells from beta-gal-injected mice secreted IL-4 and IL-5 but not interferon-gamma after in vitro stimulation with antigen. Together these data demonstrate that pDNA immunization induced a T helper type 1 (Th1) response, whereas protein immunization induced a T helper type 2 (Th2) response to the same antigen. Interestingly, priming of mice with pCMV-LacZ prevented IgE antibody formation to a subsequent i.p. beta-gal in alum injection. This effect was antigen-specific, because priming with pCMV-LacZ did not inhibit IgE anti-ovalbumin antibody formation. Most importantly, intradermal immunization with pCMV-LacZ (but not pCMV-OVA) of beta-gal in alum-primed mice caused a 66-75% reduction of the IgE anti-beta-gal titer in 6 weeks. Also, pCMV-LacZ induced specific IgG2a antibody titers and interferon-gamma secretion by Th cells in the beta-gal in alum-primed mice. The data demonstrate that gene immunization induces a Th1 response that dominates over an ongoing protein-induced Th2 response in an antigen-specific manner. This suggests that immunization with pDNA encoding for allergens may provide a novel type of immunotherapy for allergic diseases.
Animals↗
The characteristics of epilepsy in a largely untreated population in rural Ecuador.
A house-to-house survey of epileptic seizures covering a population of 72,121 persons was carried out in a rural area of northern Ecuador. A cascade system of diagnosis was used to identify all cases of epileptic seizures in this population. 1029 cases were found, of whom 881 were considered to be definite cases and 148 were possible cases. Of the 1029 cases, 56% had active epilepsy. The lifetime prevalence rate was found to lie between 12.2 and 19.5/1000 and the prevalence of active cases between 6.7 and 8.0/1000. An annual incidence rate of between 122/100,000 and 190/100,000 was estimated. Seizure type was classified without EEG data and almost half of the cases had partial seizures. In 27% of cases an aetiology was proposed on clinical grounds. This is one of few reported studies of a population that has been largely unexposed to antiepileptic drugs, providing an opportunity to study the natural history of the untreated condition. It has been suggested that treatment in newly developing epilepsy will prevent its development to a chronic condition. Only 37% of the 1029 cases had ever received antiepileptic drugs, and only 12% of the cases were taking them at the time of the survey. Despite this, a high rate of inactivity was observed, with 44% of all cases free of seizures. Nearly two thirds of the inactive cases identified had never received treatment with antiepileptic drugs. In a subgroup of untreated cases with an active condition, treatment with antiepileptic drugs was initiated and was highly effective even in cases with a long previous history. Thus the findings from this study suggest that the development of epilepsy resistant to therapy is not always associated with a long duration of untreated epilepsy.
Adolescent↗
Comparative evaluation of pentoxifylline, buflomedil, and nifedipine in the treatment of intermittent claudication of the lower limbs.
In the light of the current controversy surrounding the use of hemorheologic and vasodilator drugs in the treatment of peripheral arteriosclerosis, a comparative study was designed in order to evaluate the efficacy of pentoxifylline, buflomedil, and nifedipine in 45 patients with peripheral arterial disease (Fontaine stage II). The patients in this prospective randomized study were divided into three groups: 15 patients received pentoxifylline treatment (1,200 mg/day), 15 were treated with buflomedil (600 mg/day), and 15 with nifedipine (60 mg/day). Response to treatment was assessed at the start of the study and after forty-five and ninety days, by clinical examination, Doppler test, strain test, and digital occlusion plethysmography using a strain gauge ring. Pentoxifylline was significantly more effective (P < 0.05) than buflomedil and nifedipine at ninety days in improving walking performance, resting toe pressure, resting and postexercise ankle/brachial pressure ratio, and basal/postischemic toe-pulse ratio. Significant differences within groups were also noted for initial claudication, toe peak-flow time, pulse reappearance time (PRT/2), and maximum postischemic flow time, together with significant intergroup variables. In conclusion, pentoxifylline proved more effective than the other drugs tested in: 1. improving distal pressure and resting microcirculatory blood flow; 2. increasing postexercise distal flow, ratios, and pressures and enabling faster recuperation of basal pulse rates; 3. increasing initial claudication distance in the strain test within the test group and achieving a greater absolute subjective claudication distance than that obtained using the other treatments.
Adult↗
Esters of omega-amino acids as flexible penetration enhancers.
Series of esters of 6-aminohexanoic acid, 7-aminoheptanoic acid, and 8-aminooctanoic acid were synthesized as candidates for novel skin penetration enhancers. The permeation of theophylline expressed in the form of the enhancement factor (EF) was studied with human cadaver skin by a diffusion cell technique in the presence of the esters 1-17 in the water vehicle. The permeation in the presence of the 6-aminohexanoates 1-5 was also studied in the olive oil vehicle. Of the compounds tested, the most satisfactory enhancement in the water vehicle and oil vehicle were observed with octyl 6-aminohexanoate (EF = 45.5) and decyl 6-aminohexanoate (EF = 19.5), respectively.
Amino Acids↗
Operative management of a persistent sciatic artery aneurysm.
A 60-year-old man with a painful pulsatile mass approximately 8 cm in diameter in the right buttock was diagnosed using angiography as having a complete unilateral persistent sciatic artery aneurysm. The lesion was obliterated by proximal and distal ligation of the sciatic artery at the pelvis and the adductor magnus canal. A femoropopliteal bypass was performed with inverted autologous saphenous vein. The residual mass was subsequently drained because of persistent symptoms. Postoperative recovery was good.
Aneurysm↗
Managing post-intubation injuries.
Many patients who experience a long, complicated illness require endotracheal intubation and tracheostomy. A few patients develop potentially life-threatening post-intubation injuries. In this overview, common post-intubation injuries, emergency and surgical treatment for these complications, and pre and postoperative nursing management of these patients are discussed.
Emergencies↗
Antiepileptic drug treatment in a community health care setting in northern Ecuador: a prospective 12-month assessment.
The results of a prospective assessment of antiepileptic drug treatment carried out over a 12-month period, in the context of existing community health care in a rural area of a developing country (a highland region of northern Ecuador), are reported. A house to house survey defined all patients in the area with a history of epileptic seizures, and 192 patients with active epilepsy were recruited into the programme. These patients were randomised to treatment with carbamazepine or phenobarbital, and 139 completed the assessment. Treatment was carried out by health visitors and rural doctors, monitored by a team of neurologists, and standard treatment regimens were used. Treatment was effective in controlling seizures, 53% of the patients were rendered entirely seizure free in the second 6 months of therapy, and a further 14% had a 50% or more reduction in seizures. These results were similar to those reported in hospital based studies in developed countries. No significant differences were found between the efficacy and safety of phenobarbital or carbamazepine. Antiepileptic drug levels were monitored during the study, and ranges similar to those found in developed countries were recorded. Compliance was good. In view of the successful treatment in this community control programme, we would recommend that community programmes for the control of epilepsy in rural settings should be given a higher priority in the planning of health care provision than is commonly the case. Finally, the programme afforded the opportunity to study the efficacy of treatment in patients with chronic long-standing epilepsy, who had not been previously treated, and the results of this treatment were good.
Adolescent↗
Three-dimensional reconstruction of Coxiella burnetii-infected L929 cells by high-voltage electron microscopy.
Previous examination of thin sections of L929 cells heavily infected with the Q fever Priscilla isolate by conventional transmission electron microscopy indicated that the rickettsiae resided within multiple vacuoles. The present study using high-voltage electron microscopy and three-dimensional reconstruction revealed that, in heavily infected cells, the rickettsiae, in fact, reside in one multilobed vacuole. As a result of asymmetric cell division, the multilobed vacuole containing the rickettsiae apparently segregates into one daughter cell, while the companion daughter cell emerges parasite free. This likely explains the appearance of naive uninfected cells in long-term-infected (i.e., ca. 2 years) cell populations that had not been supplemented with uninfected L929 host cells.
Animals↗
Early open mitral commissurotomy: long-term results.
It has frequently been suggested that early mitral commissurotomy could improve long-term results in patients with severe mitral stenosis. However, the real advantages of this procedure have yet to be demonstrated. To evaluate this hypothesis, we retrospectively studied 397 patients who underwent operation for mitral stenosis in our unit between 1978 and 1988. Forty of these patients (group I) fulfilled the criteria for early mitral commissurotomy: being young (average age 33 years), being asymptomatic or showing few symptoms, and being in sinus rhythm. The remaining 357 patients who underwent operation during the same period of time served as control (group II). Mitral valve replacement (p < 0.05) and associated tricuspid annuloplasty (p < 0.05) occurred less frequently in patients from group I than it did in patients from group II. Survival after 11 years for patients with early mitral commissurotomy was 100%, 90% of whom were in functional class I, were in sinus rhythm, and were receiving no medication whatsoever. Ninety-six percent of these patients were free of complications after 11 years, compared with 73% of patients in group II (p < 0.05). In our opinion, these results support the use of early mitral commissurotomy for young patients in sinus rhythm, who are symptom free, who are and who have a mitral valve area is 1.3 cm2 or less.
Adolescent↗
Gene therapy via primary myoblasts: long-term expression of factor IX protein following transplantation in vivo.
We have explored the use of primary myoblasts as a somatic tissue for gene therapy of acquired and inherited diseases where systemic delivery of a gene product may have therapeutic effects. Mouse primary myoblasts were infected with replication-defective retroviruses expressing canine factor IX cDNA under the control of a mouse muscle creatine kinase enhancer and human cytomegalovirus promoter. The infected myoblasts were injected into the hindlegs of recipient mice and levels of secreted factor IX protein were monitored in the plasma. We report sustained expression of factor IX protein for over 6 months without any apparent adverse effect on the recipient mice.
Animals↗
Separation techniques for biotechnology in the 1990s.
Scientists are constantly looking for better and cheaper separation techniques to replace or complement the current technology. Over the past few decades, and in particular the last 10 years, new separation techniques or modifications of existing techniques have become available for separating compounds from complex sample matrices. There are many areas, however, where the separation technology is not sufficient to achieve high purity and yield while remaining cost effective. In the area of biotechnology, separation techniques are urgently needed to meet demands for ultra-high purity and yield. Thus, a variety of techniques are being developed to address these needs. Generally, biological compounds for the pharmaceutical and biotechnology industries must be obtained at greater than 99.9% purity (sometimes greater than 99.99%) while maintaining high yield. In any area of chemistry this degree of purity would cause problems; in biotechnology it is even more difficult to achieve because of the complex sample matrices. In addition, the compounds of interest may be very similar to impurities or contaminants in the sample matrix, and the compounds could be denatured (or even destroyed) by certain solvents and/or high temperature. In particular, three areas of biotechnology have presented scientists with problems in separations: cell separations, DNA-RNA separations, and protein-peptide separations. The current technology available and possible future trends in these areas are discussed, and also problems to be solved in the future.
Base Sequence↗
Circulating human or canine factor IX from retrovirally transduced primary myoblasts and established myoblast cell lines grafted into murine skeletal muscle.
We have used retroviral vectors to introduce human or canine factor IX cDNAs into cultured primary murine and canine myoblasts and into the established murine myoblast cell line C2C12. In all cases, the stably infected cells produced biologically active factor IX in culture and secreted detectable amounts into the culture medium both before and after differentiation of the cells into myotubes. Myoblasts and differentiated myotubes are therefore capable of performing all the posttranslational modifications of the coagulation factor required for biological activity. We have grafted the genetically modified myoblasts into skeletal muscles of nude mice and have detected stable levels of circulating human factor IX for up to two months after grafting. We propose that grafting genetically modified primary myoblasts or established myoblast cell lines into skeletal muscle may represent a useful approach to gene therapy for a variety of genetic diseases, including intrinsic muscle disease and defects in circulating proteins as in the hemophilias.
Animals↗
Effects of d-amphetamine and ethosuximide on responding under delayed-matching-to-sample procedures with differential and nondifferential outcomes.
Pigeons were exposed to delayed-matching-to-sample (DMTS) procedures in which food or a flash of the feeder light followed correct responses. When these consequences were correlated with a particular stimulus (e.g., food followed matching responses to red and a flash of the feeder light followed matching responses to green), accuracy was higher (i.e., stimulus control was greater) than when discriminative stimuli and consequences were not correlated. Although stimulus control in the absence of drug appeared to be weaker under the uncorrelated procedure, neither d-amphetamine (0.5-3.0 mg/kg) in Experiment 1 nor ethosuximide (40-160 mg/kg) in Experiment 2 disrupted accuracy to a greater extent under that procedure. These results, like those of a prior investigation, suggest that drug effects are similar under DMTS procedures regardless of whether correlated or uncorrelated outcomes are arranged.
Animals↗
Natural history of left ventricular performance at rest and during exercise after aortic valve replacement for aortic regurgitation.
Previous studies of left ventricular performance in aortic regurgitation uniformly indicate improvement within the year after aortic valve replacement but differ regarding the likelihood of additional later improvement. To resolve this difference, to more precisely define the pattern of postoperative left ventricular performance variation, and to assess the impact of valve replacement on ejection fraction during exercise, we evaluated radionuclide cineangiograms obtained annually or nearly annually for approximately 5 years in 21 prospectively studied patients who had undergone valve replacement for aortic regurgitation. Ejection fraction rose from less than 8 months before operation to 5-11 (average 7) months after operation and continued to rise for 1 additional year (rest) and 2 additional years (exercise) before reaching a stable plateau until the final study 54-72 (average 63) months postoperatively. Mean ejection fractions at rest were 45% preoperatively, 50% less than 1 year postoperatively (p = 0.12), 54% at year 1-2 (p = 0.01 versus less than 1 year), 56% at year 2-3 (NS versus year 1-2) and year 4-6 (NS versus year 1-2 or 2-3), and during exercise were 39% preoperatively, 49% less than 1 year postoperatively (p less than 0.01), 54% at year 1-2 (p less than 0.01 versus less than 1 year, NS versus year 2-3, p less than 0.05 versus year 4-6), 60% at year 2-3, and 61% at year 4-6 (NS versus year 2-3). Late improvement was found most consistently among patients with relatively depressed performance before operation.(ABSTRACT TRUNCATED AT 250 WORDS)
Aortic Valve↗
Recasting the approach to the treatment of potentially malignant ventricular arrhythmias after the CAST study.
The best therapeutic approach to the therapy of potentially malignant ventricular arrhythmias is still unknown, particularly in view of the increased mortality with flecainide and encainide shown in the CAST study. Various ongoing studies, particularly with amiodarone, will show whether better results can be obtained with other agents. Flecainide and encainide do, however, have a restricted place when other agents cannot be used. Low-dose amiodarone with low-dose flecainide may be worth trying.
Anilides↗
Effect of chronic opioid treatment on phagocytosis in Tetrahymena.
Opioid inhibition of phagocytosis in the protozoan ciliate Tetrahymena is antagonized by naloxone and this antagonism can be surmounted by increasing agonist concentration, which suggests a receptor-mediated mechanism. Desensitization of the opioid effect is time dependent in addition to concentration dependent. Chronic exposure to opioids results in the development of tolerance to the inhibitory effect of the agonists, and withdrawal of the latter results in a decrease in phagocytic capacity, which suggests that a state akin to dependence has been developed in these cells. Naloxone appears to behave as a partial agonist in tolerant cells, and there seems to exist cross-tolerance to mu and delta agonists.
Animals↗