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Biomedical subjects

A M Roberts

Publications and source records attributed to A M Roberts.

At least 19 recordsLinked to original sources
PubMed2000

Chemoreflexes: an experimental study.

HYPOTHESIS: Transmyocardial laser revascularization (TMLR) will not denervate the heart, because it does not destroy all of the afferents. This study was designed to determine if stimulation of cardiac sympathetic and vagal afferents from an area of the left ventricle treated with TMLR could evoke reflex effects, and thus whether TMLR would denervate the heart. METHODS: The effect of TMLR on reflexes evoked by chemically stimulating cardiac afferents was examined in 9 dogs. Bradykinin and capsaicin were applied topically or injected into the left anterior descending coronary artery before and after TMLR and after bilateral vagotomy and sympathectomy. Aortic (AoP) and left ventricular pressures (LVP) and electrocardiography were monitored. The first derivatives of LVP (dP/dt) were calculated. RESULTS: Topical bradykinin elicited variable hemodynamic responses. Topical capsaicin evoked pressor responses, increasing mean (+/- SEM) AoP (105+/-9 to 115+/-9 mm Hg; P<.001) and positive dP/dt (+dP/dt) (1032+/-81 to 1159+/-10 mm Hg/s; P<.01) before TMLR. Intracoronary capsaicin evoked a depressor response before TMLR. Pressor responses remained intact after TMLR with increases in mean AoP and +dP/dt (115+/-6 to 128+/-5 mm Hg and 1039+/-98 to 1136+/-100 mm Hg/s, respectively; P<.01). Depressor responses also remained intact after TMLR (91+/-10 vs 101+/-11 mm Hg [P<.02], and 865+/-104 vs 931+/-104 mm Hg/s [P<.05], respectively). Hemodynamic responses were diminished after bilateral vagotomy and abolished after bilateral sympathectomy. CONCLUSION: Since activation of cardiac afferent nerves and reflex responses remained intact after TMLR, but changed after vagotomy or sympathectomy, TMLR does not denervate the heart sufficiently to be the cause of improved angina after TMLR.

Afferent Pathways↗
PubMed1999

Pulmonary artery occlusion and reperfusion causes microvascular constriction in the rabbit lung.

INTRODUCTION: Reperfusion injury of the lung after ischemia is associated with altered alveolar blood flow and ventilation-perfusion mismatch, which is a significant cause of morbidity and mortality after lung transplantation. We examined the effect of ischemia and reperfusion on the tone of individual subpleural arterioles in the pulmonary circulation by using video microscopy with polarized epiillumination. METHODS: In 11 open-chested rabbits anesthetized with pentobarbital (2.3 to 2.5 kg), we ventilated the lungs through the lower trachea (air or 50% oxygen) and examined the response of subpleural arterioles (diameter 75 +/- 13 microm) to ischemia (76 +/- 32 min) of the right lung caused by occluding the right main pulmonary artery. Observations were made during baseline, occlusion, and during early (20 to 32 min) and late (48 to 63 min) reperfusion using a long working distance lens (550x) with a dipping cone held at the pleural surface while the lungs were statically inflated (10 cm H2O) with oxygen for brief periods. Data are expressed as mean +/- standard deviation. RESULTS: Arteriolar diameter was decreased 57% +/- 19% during early reperfusion. There was a decrease in blood flow and alveolar walls were pale, indicating reduced capillary perfusion. During late reperfusion, arteriolar diameter was diminished (19% +/- 26%); flow was still reduced. Overall pulmonary vascular resistance increased during early reperfusion but returned to baseline level during late reperfusion. Arterial partial pressure of oxygen averaged 200 mm Hg during ischemia and reperfusion. CONCLUSIONS: Constriction of small arterioles by ischemia and reperfusion can have a significant effect on the early phase of ventilation-perfusion mismatch and pulmonary dysfunction by altering alveolar perfusion. This response does not appear to be mediated by hypoxia because it was not prevented by ventilation with oxygen.

Animals↗
PubMed1999

Exhaled nitric oxide measurements in a population sample of young adults.

In epidemiologic studies of asthma there is a group with recent wheeze, but with no airway hyperresponsiveness (AHR), in whom it is unclear whether any significant airway abnormality exists. Exhaled nitric oxide (NO) has been proposed as a measure of airway inflammation. We measured exhaled NO in a population sample of 306 young adults who also underwent bronchial challenge with histamine or a bronchodilator test. Subjects blew into a 3-L Tedlar bag against a 2-mm-diameter resistance to close the soft palate and exclude nasal air. The NO content of expired gas from a single breath was analyzed by chemiluminescent analyzer. Exhaled NO was log-normally distributed in the population sample and duplicate measurements were highly reproducible (intraclass correlation coefficient = 0.98). Exhaled NO correlated significantly with airway responsiveness, measured as the dose-response ratio to histamine (r = 0.39, p < 0.001) and with peripheral blood eosinophils (r = 0.35, p < 0.001). Exhaled NO was significantly greater in asthmatic subjects (geometric mean, 22.2; 95% confidence intervals, 16.1 to 30. 7 ppb) than in normal subjects (7.8, 7.1 to 8.4, p < 0.001) or in subjects with wheeze but no AHR (8.8, 7.5 to 10.3, p < 0.001). We conclude that exhaled NO is log-normally distributed, is highly reproducible and discriminates well among subjects, suggesting that it is both a feasible and useful measurement for epidemiologic studies of asthma. The findings suggest that wheeze in the absence of AHR is unlikely to be associated with airway inflammation.

Adult↗
PubMed1999

Pulmonary rapidly adapting receptor stimulation does not increase airway resistance in anesthetized rabbits.

In open-chest artificially ventilated rabbits, removal followed by replacement of positive end-expiratory pressure (PEEP maneuver) favors stimulation of airway rapidly adapting receptors (RARs). The purpose of the present study was to determine whether activation of RARs can cause bronchoconstriction. We measured airway pressure, airflow, and tidal volume, and calculated dynamic lung compliance and total lung resistance. PEEP maneuver increased airway pressure swings (16.4 +/- 4% above control; p = 0.0016) and decreased compliance (to 84.8 +/- 2.8% of control; p = 0.0002) without changing resistance (108.0 +/- 4.4% of control; p = 0.85). On the other hand, the resistance increased greatly (93 +/- 13%, p < 0.01) after intravenous injection of acetylcholine or electrical stimulation of vagal efferents, indicating that our system could detect increases in the resistance. In a separate group, we stimulated RARs by stroking the trachea with a cotton tip (tickling), tickling produced cough, manifested by increased pressure and flow without resistance changing. These changes were abolished after paralysis with succinylcholine. Because we did not detect an increase in airflow resistance during activation of RARs by the PEEP maneuver and tickling, we conclude that increase in resistance may not be an important reflex component of airway RARs.

Acetylcholine↗
PubMed1998

Potentiation of pulmonary arteriolar vasoconstriction to endothelin-1 by inhibition of nitric oxide synthesis in the intact lung.

OBJECTIVE: To observe pulmonary arteriolar effects of endothelin-1 (ET-1) in the intact lung and determine if constriction to ET-1 is potentiated by inhibition of nitric oxide (NO) synthesis. METHODS: In anesthetized male Sprague-Dawley rats with open chest, the lungs were ventilated with air through the lower trachea and in vivo responses of pulmonary arterioles were examined by video microscopy. Observations were made when the lungs were statically inflated with oxygen to a pressure of approximately 10 cm H2O for brief periods. A lens with a dipping cone was held at the pleural surface. ET-1 (10(-7)-10(-5)M; approximately 0.1 ml) was applied topically to the fluid layer under the dipping cone. RESULTS: ET-1 (10(-6)M) constricted parent arterioles 60 +/- 5 microns in diameter by 52 +/- 12% (range: 20-100%) and branches 45 +/- 3 microns in diameter by 36 +/- 4% (19-48%). Constriction persisted and there was a dramatic long-lasting decrease in flow. Alveolar walls quickly became pale, indicating reduced capillary perfusion. A lower concentration of ET-1 (10(-7)M) constricted (p > 0.05) parent arterioles 61 +/- 4 microns in diameter by 7 +/- 3% initially, and by 13 +/- 8% after 14 +/- 2 minutes, while smaller branches did not respond. In separate experiments, infusion of the NO synthase inhibitor L-NAME (1 mg/kg per minute), modestly (10 +/- 3%) decreased (p < 0.05) baseline parent arteriolar diameter from 72 +/- 7 microns to 64 +/- 5 microns. Branch diameter changed insignificantly from 42 +/- 7 microns to 38 +/- 7 microns. After L-NAME, ET-1 (10(-7)M) constricted (p < 0.05) parent arterioles by 17 +/- 4% initially and 40 +/- 14% after 14 +/- 2 minutes. Concurrently, branches constricted (p < 0.05) by 14 +/- 4% and 26 +/- 15%. CONCLUSIONS: Arterioles less than 80 microns in diameter were very responsive to ET-1, which could be a factor in altering pulmonary microvascular resistance. Inhibition of NO synthesis appears to potentiate constriction to ET-1.

Animals↗
PubMed1997

Effects of platelet-activating factor on arteriolar and venular tone in rat trachea.

Platelet-activating factor (PAF) causes altered vascular tone in the mesenteric, pulmonary, and skeletal muscle vascular beds, enhanced macromolecular leak in postcapillary venules, and bronchoconstriction. In spontaneously breathing, anesthetized male Sprague-Dawley rats, we examined responses of individual tracheal microvessels using intravital video microscopy with epi-illumination using a polarizing filter and a long working distance lens (10x). Topical application of PAF (0.1 ml; 10(-9), 10(-7), or 10(-5) M) caused venules (diameter, 51 +/- 5 microm, mean +/- SEM) to constrict in a concentration-dependent fashion. Venoconstriction began within 0-3 min and was maximal within 10 min. In contrast, PAF (10(-5) M) applied to arterioles (diameters, 37 +/- 1 microm) ultimately caused constriction by 21 +/- 7%, but in three dilation (38 +/- 9%) occurred first. PAF (10(-7) and 10(-9) M) applied to arterioles (diameter 36 +/- 3 and 38 +/- 3 microm, respectively) caused no significant change in diameter. Infusion of BN52021, a PAF receptor antagonist, completely blocked constriction of venules and arterioles to PAF (10(-5) M), but dilation (17 +/- 0.2%) still occurred in three of five arterioles. Infusion of Nomega-nitro-l-arginine methyl ester (L-NAME; 1 mg/kg/min), a nitric oxide (NO) synthase inhibitor, potentiated venoconstriction by 34 +/- 18% in response to PAF (10(-7) M) and blocked arteriolar dilation to PAF (10(-5) M). Arteriolar constriction was unaffected by inhibiting NO release. Topical application of L-NAME (10(-3) M) constricted venules (n = 6) by 13 +/- 2% and arterioles (n = 5) by 26 +/- 4%. Venules constricted 33 +/- 15% less to PAF (10(-7) M, n = 5) following topical L-NAME (33 +/- 15%) than with infused l-NAME. Arterioles (n = 5) constricted 27 +/- 4% to PAF (10(-5) M) after topical l-NAME, no different from the group receiving infused L-NAME. We conclude that (1) PAF has a greater vasoconstrictive effect on tracheal venules than arterioles; (2) arterioles have a biphasic response to PAF at some concentrations; (3) PAF-induced vasoconstriction, but not dilation, is receptor mediated; (4) nitric oxide attenuates tracheal venoconstriction and may cause arteriolar dilation in response to PAF; and (5) endogenous release of NO appears to modulate the basal tone of tracheal arterioles more than venules.

Analysis of Variance↗
PubMed1997

First antenatal visits and metronidazole.

OBJECTIVE: We evaluated the timing of initial antenatal visits to better characterize possible use of metronidazole or other antimicrobials for common reproductive tract infections in early pregnancy. STUDY DESIGN: We determined timing of initial antenatal evaluation in five busy and representative Denver, Colorado, practice settings (most recent 50 patients). RESULTS: Most women were evaluated after completion of 9 weeks of pregnancy. Women seen in private settings received the initial visit earlier than did women in publicly supported clinics. CONCLUSION: Pregnant women with a common reproductive tract infection and bacterial vaginosis can be "screened and treated" at the initial antenatal examination.

Female↗
PubMed1997

Comparative biomechanical analysis of a new circumferential flexor tendon repair and a modified Kessler repair.

We present the technical details and the results of a biomechanical analysis of a new type of circumferential flexor tendon repair, designed with the more stringent requirements of zone II injuries in mind. Apart from good initial strength we aimed for a design with little bulk at the repair site and good control of the tendon edges. The new repair is achieved using a single, continuous, inverting and locking suture of the periphery of the tendon. The repair was compared with a Kessler core suture of 4/0 polydioxanone, with Tajima and Strickland modifications, to which has been added a simple running circumferential suture (6/0 polypropylene), the repair currently used in our unit. Fresh human cadaver flexor tendons were divided and repaired by one of the two techniques (n = 12 for each technique), using 5/0 polypropylene for the new circumferential suture. A third group of tendons (n = 8) were divided and repaired with a 5/0 multifilament steel circumferential suture. The repaired tendons were tested at longitudinal stress to failure. The first two groups of tendons were tested at two crosshead speeds. Overall, crosshead speed had no effect on ultimate tensile strength (P = 0.5). The 5/0 polypropylene circumferential repair (median 32.29 N) was significantly stronger than the Kessler repair (median 24.03 N) (P = 0.046). The circumferential repair was significantly stronger with steel (median 56.04 N) than with polypropylene (median 32.29 N) (P = 0.007). The size of the repair site, resistance to gap formation and the patterns of failure were analysed on video recordings.

Biomechanical Phenomena↗
PubMed1997

Measurement of IgE antibodies against purified grass pollen allergens (Lol p 1, 2, 3 and 5) during immunotherapy.

BACKGROUND: IgE titres tend to rise early after the start of immunotherapy, followed by a decline to pre-immunotherapy levels or lower. OBJECTIVES: We were interested to know whether the early increase in IgE antibodies includes new specificities of IgE, and whether these responses persist. METHODS: Sera of 64 patients undergoing grass pollen immunotherapy were tested for IgE against four purified grass pollen allergens: Lol p 1, 2, 3, and 5. At least two serum samples were taken, one before the start of therapy and one between 5 and 18 months after the first immunization (mean: 10 months). RESULTS: The mean IgE responses to Lol p 1, 2 and 3 showed a moderate but not significant increase. In contrast, the mean IgE response to Lol p 5 showed a significant decrease of > 30%. IgE against total Lohum perenne pollen extract moderately increased (> 20%), showing that a RAST for total pollen is not always indicative for the development of IgE against its major allergens. For > 40% of the patients it was found that IgE against one or more of the four allergens increased, while IgE against the remaining allergen(s) decreased. For 10 sera the ratio of IgE titres against at least two allergens changed by at least a factor of 5. The changes in specific IgE also included conversions from negative (< 0.1 RU) to positive (0.6 to 5.0 RU) for five patients. For two patients, the induction of these 'new' IgE antibodies against major allergens was shown to result in a response that was persistent over several years. CONCLUSION: Although active induction of new IgE specificities by immunotherapy was not really proven, the observations in this study indicate that monitoring of IgE against purified (major) allergens is necessary to evaluate changes in specific IgE in a reliable way.

Allergens↗
PubMed1996

Direct effects of meconium on rat tracheal smooth muscle tension in vitro.

Increased airway resistance is a component of the meconium aspiration syndrome. Experiments were done to determine whether meconium can have a direct affect on tracheal smooth muscle tension. Tracheal segments (4-5 mm long) were isolated from male Sprague-Dawley rats and suspended in organ baths with physiologic salt solution at 37 degrees C gassed with 95% O2-5% CO2. Each segment was attached to a fixed glass rod on one side and to a force displacement transducer on the other side to measure transverse tension. The segments were stretched to 1.5 g of tension and equilibrated for 2-5 h. Human meconium was diluted in physiologic salt solution (20 g/100 mL) and filtered through gauze. Tension was generated in the segments by adding acetylcholine (10(-6) M) to the tissue bath. Addition of meconium to the organ bath (0.1-5 mg/mL) caused tracheal smooth muscle relaxation in 44% of tracheal segments tested. Contraction occurred in 8% of tested segments, but only at the intermediate and low doses. The amount of relaxation increased significantly in a concentration-dependent manner. These responses were not affected by pretreating segments with indomethacin, removing the tracheal epithelium, using KCl to generate tone, or by heating meconium above 60 degrees C for 1 h. Addition of oleic acid to the organ bath (3.5 x 10(-6) to 3.5 x 10(-4) M) caused concentration-dependent tracheal smooth muscle responses (with relaxation predominating at 3.5 x 10(-4) M and contraction predominating at 3.5 x 10(-6) M). These results suggest that meconium can cause tracheal smooth muscle relaxation by a mechanism that does not appear to be mediated by cyclooxygenase products, by the tracheal epithelium, or a protein. The direct action of meconium on tracheal smooth muscle, which may in part be mediated by a fatty acid, does not appear to contribute significantly to the increased airway tone associated with the meconium aspiration syndrome.

Acetylcholine↗
PubMed1995

Effect of feeding state on the response of horses to repeated bouts of intense exercise.

Four mature Standardbred horses were used in a 2-period cross-over design experiment to evaluate the effect of feeding state (fed or fasted) on metabolic response to 2 repeated bouts of exercise. Horses were either fasted 15 to 16 h before exercise or fasted for 12 h and then fed 2 kg of whole corn 2.5 to 3 h before exercise. In the first period, 2 horses in each feeding state were exercised. In the second period, the treatments were switched. The exercise test consisted of 2 exercise bouts separated by a 90 min recovery period. Each exercise bout included a warm-up phase and a high intensity phase (1600 m at 11 m/s on a 2% graded treadmill). Blood samples collected during the exercise test were analysed for glucose, non-esterified fatty acids (NEFA), insulin and lactate concentrations. Fasted horses had lower insulin concentrations and higher NEFA concentrations at the onset of exercise (P < 0.05). NEFA concentrations were consistently higher (P < 0.05) in the fasted horses until the high intensity phase of the second exercise bout. Feeding state did not affect heart rate or plasma lactate responses to exercise. Plasma glucose concentrations tended to decline in the fed horses during the first exercise bout. Neither a positive nor a negative effect of feeding state on horses performing repeated bouts of intense exercise were found.

Animals↗
PubMed1995

Differences in the capsaicin-induced dilation of arterioles and venules in rat striated muscle.

We previously found that capsaicin can dilate third-order arterioles in striated muscle by a mechanism that appears to involve release of endogenous calcitonin gene-related peptide (CGRP). Experiments were done to determine 1) whether capsaicin has similar effects on larger arterioles and venules and 2) whether relaxation involves endogenous CGRP and synthesis of endothelium-derived relaxing factor. In male Sprague-Dawley rats anesthetized with pentobarbital (50 mg/kg, i.p.), we examined responses of first- and second-order microvessels in the cremaster muscle using video microscopy. Addition of capsaicin (0.1 microgram/ml) to vessels constricted by norepinephrine (10(-7) M) dilated 1A's by 91% +/- 28%, 2A's by 113% +/- 18% 1V's by 11% +/- 6% and 2V's by 42% +/- 18%. Capsaicin in the presence of the specific CGRP receptor antagonist CGRP (8-37) caused an attenuated arteriolar dilation but had no significant venodilatory effect (1A's 29% +/- 18%, 2A's 55% +/- 14%, 1V's 7% +/- 3%, 2V's 16% +/- 3%). Pretreatment with N-nitro-L-arginine methyl ester (10(-4) M) did not prevent capsaicin-induced arteriolar dilation (A1's 118% +/- 11%; A2's 129 +/- 24%) but blocked capsaicin-induced venodilation (V1's constricted by 5% +/- 5%; V2's constricted by 2% +/- 6%). N-nitro-L-arginine methyl ester also blocked CGRP-induced dilation of both orders of venules, but not arterioles. These data suggest that capsaicin-induced dilation may involve synthesis of endothelium-derived relaxing factor in the venules but not in the arterioles.

Animals↗
PubMed1994

A novel method to assess reactivities of retinal microcirculation.

This study introduces a novel method of bovine retinal microcirculation preparation to assess reactivities of retinal microvessels in ex vivo. This preparation is perfused intraluminally through the retinal artery. Effects of vasoactive hormones on these microvessels can be studied by perfusion or topical application to muscle bath. Effects of these compounds on the retinal microvessels of 1A (180- to 200-microns diameters), 2A (50- to 60-microns diameter), and 3A (20- to 30-microns diameter) can be assessed simultaneously using video microscopy. In this study, the water-soluble compound endothelin-1, when applied topically, caused dose-dependent vasoconstriction of all microvessels but had no effect when perfused intraluminally. On the other hand, lipid-soluble prostaglandin F2 alpha (PGF alpha) caused dose-dependent vasoconstriction when administered either intra- or extraluminally. Furthermore, preconstricted retinal arterioles (by PGF alpha) were dilated in a dose-dependent manner when acetylcholine was perfused through the retinal artery. This vasodilation was attenuated by atropine or N3-monomethyl arginine, a nitric oxide synthase inhibitor. Topical potassium chloride also caused dose-dependent vasoconstriction of all retinal microvessels. Fluorescein angiography showed no breakdown of the blood-retinal barrier. Thus, in this ex vivo perfused bovine retinal microcirculation preparation, the water-soluble compounds may not cross the blood-retinal barrier to affect microcirculation while lipid soluble can affect this circulation. Additionally this study shows that endothelial-derived compounds, endothelin and nitric oxide, caused vasoconstriction and dilation, respectively.

Acetylcholine↗
PubMed1993

Nucleotide sequence of cDNA encoding the group II allergen of cocksfoot/orchard grass (Dactylis glomerata), Dac g II.

Cocksfoot/orchard grass (Dactylis glomerata) anther cDNA clones encoding the group II allergen Dac g II were previously isolated on the basis of immunoreactivity of human, rabbit, and murine antibodies with a 24-kDa protein expressed as a fusion protein with beta-galactosidase. Nucleotide sequencing reveals an open reading frame predicting expression of a 98-amino-acid (11-kDa) polypeptide exhibiting > 90% homology with the group II allergen of Lolium perenne, Lol p II. In vitro translation of different sized clone fragments generated by polymerase chain amplification confirms eukaryotic expression of a 10-12-kDa polypeptide by SDS-PAGE and the position of a translational stop apparently unrecognized during expression of lambda gt11 in E. coli. The unusual characteristics of the prokaryote-expressed fusion proteins may be exerting conformational alterations in Dac g II, as reflected by previous demonstrations of differences in human IgE immunoreactivity. Northern blot analysis using PCR-generated partial and full-length probes suggests that group II allergens may be encoded by a different family or families of temporally expressed genes from those encoding group I major allergens, although a group I gene may have been the progenitor.

Allergens↗
PubMed1993

Arteriolar dilation mediated by capsaicin and calcitonin gene-related peptide in rats.

In addition to altering vascular tone by stimulating primary afferent nerves and acting through reflex pathways, capsaicin acts locally. We examined effects of topically applied capsaicin on arteriolar diameter in striated muscle and tested the hypothesis that capsaicin can alter microvascular tone by releasing substance P (SP) or calcitonin gene-related peptide (CGRP). In anesthetized rats, the right cremaster muscle was exposed and suspended in a tissue bath filled with a physiological salt solution. Diameters of third-order arterioles were displayed and measured using in vivo video microscopy. In 17 of 20 rats, addition of capsaicin (3 x 10(-7) M) to the bath dilated arterioles (85 +/- 14% above control). Failure of a second administration of capsaicin to produce a sustained dilation in 6 of 7 arterioles that had previously dilated to capsaicin is consistent with the hypothesis that this agent causes depletion of an endogenous vasodilator. Pretreatment with an SP inhibitor did not alter capsaicin-induced dilation. CGRP (1 x 10(-10) to 2 x 10(-8) M) caused dilation similar to that caused by capsaicin. Pretreatment with a CGRP inhibitor to the bath prevented capsaicin-induced dilation, but not constriction. These results suggest that capsaicin can dilate microvessels by releasing CGRP, which can modulate tone.

Animals↗
PubMed1992

Isolation and amplification of human IgE Fd encoding mRNA from human peripheral blood lymphocytes.

In order to establish the feasibility of applying recombinatorial library technologies to investigate human in vivo IgE responses, and as a pre-requisite of recombinatorial library construction, we have attempted to determine workable peripheral blood sample volumes required for isolation of mRNA for polymerase chain reaction (PCR) amplification of human IgE Fd encoding sequences. Cells secreting chimeric human IgE monoclonal antibody specific for the hapten NIP were used to establish the conditions for specific amplification of C epsilon 1 domain and Fd encoding sequences, as determined by Southern hybridisation. Amplification of C epsilon 1 domain sequences could be achieved using as few as ten cultured cells as the source of RNA. Specific IgE+ B cell enrichment using immuno-magnetic particles prior to RNA extraction was, however, required to obtain amplification of IgE C epsilon 1 and Fd fragments from lymphocytes prepared from 40 ml human peripheral blood. IgG1+ B cell enrichment from similar samples was not required for detectable amplification of human C gamma 1 cDNA sequences. However, this procedure improved amplification efficiency. Optimisation of methods to separate specific B cell populations, or specific RNA/cDNA sequences, will facilitate in vitro generation of human IgE Fab fragments from peripheral blood.

B-Lymphocytes↗