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Biomedical subjects

J M Hanifin

Publications and source records attributed to J M Hanifin.

At least 109 records · Page 6Linked to original sources
PubMed1985

Elevated leukocyte phosphodiesterase as a basis for depressed cyclic adenosine monophosphate responses in the Basenji greyhound dog model of asthma.

The BG dog manifests various characteristics of human asthma, including airway hyperreactivity to low concentrations of methacholine. Studies have suggested that airway hyperreactivity in asthma is related to inadequate intracellular cAMP responses. We studied cAMP characteristics in MNL from 19 BG and 14 mongrel dogs. beta-Adrenergic receptors were assessed by 125I CYP in the presence and absence of propranolol. The responses of cAMP to ISO were measured by radioimmunoassay. Adenylate cyclase activity was determined in homogenized MNL preparations by cAMP generation. PDE activity was quantitated by radioenzyme assay. Mongrel dog leukocyte ISO-stimulated cAMP levels doubled, whereas there were negligible increases in MNL from BG dogs. Basal PDE levels were higher in BG dogs than in mongrel dogs. The PDE inhibitor Ro 20-1724 restored ISO-stimulated cAMP responses in MNL of BG dogs. Adenylate cyclase activity was not lower in MNL homogenates from BG dogs than in mongrel dogs. Cells from both BG and mongrel dogs demonstrated similar receptor numbers and affinities of saturable, specific beta-adrenergic binding over a 10 pM to 400 pM range. Our results suggest that depressed cAMP responses in BG dogs are due to high PDE activity rather than to a defect in the beta-adrenergic receptor adenylate cyclase system.

Adenylyl Cyclases↗
PubMed1985

Comparison of histamine release in human skin mast cells induced by morphine, fentanyl, and oxymorphone.

Human leukocyte and skin mast cell preparations were incubated with morphine sulfate in concentrations ranging from 1.5 X 10(-5) M to 4.5 X 10(-3) M. Skin mast cells also were incubated with oxymorphone and fentanyl in the same concentrations. Human leukocytes did not release histamine in response to any concentration of morphine. In skin mast cells, histamine release by morphine first was detected at 1.5 X 10(-4) M. Histamine release further increased at 5.0 X 10(-4) M with no incremental increase at higher concentrations. Oxymorphone and fentanyl failed to release histamine at any concentration. Histamine release by morphine required calcium but was not influenced by changes in the 1-4 mM range. Skin mast cell preparations were pretreated for 30 min in naloxone 5 X 10(-4) M and then morphine 5 X 10(-4) M was added for 30 min without removing naloxone. Naloxone neither released histamine nor inhibited morphine-induced histamine release. The release of histamine by morphine but not equimolar concentrations of fentanyl and oxymorphone indicates that histamine release by narcotics is not a nonspecific effect of high drug concentration. The failure of naloxone to inhibit morphine-induced histamine release suggests that histamine release by morphine is not dependent on opiate receptor binding or activation. These results indicate that this human mast cell preparation will be useful in further understanding the mechanism of histamine release induced by morphine and other agents.

Cell Membrane↗
PubMed1985

Thiobarbiturate-induced histamine release in human skin mast cells.

Human skin mast cell preparations were incubated with thiopental, thiamylal, methohexital, and pentobarbital in concentrations ranging from 10(-5) M to 10(-3) M. Both thiopental- and thiamylal-induced dose-related histamine release, with thiamylal having a significantly greater effect than thiopental (P less than 0.05). In contrast, incubation of skin mast cell preparations with the same concentrations of pentobarbital and methohexital failed to increase histamine release above spontaneous levels at any concentration. The release of histamine by thiopental and thiamylal was not accompanied by the leakage of lactic dehydrogenase (LDH). Although a demonstration of histamine release in vitro is not proof that clinical symptoms are causally related to histamine release in vivo, methohexital may be preferred as the induction agent in patients showing extreme sensitivity to histamine (asthmatics) or increased histamine releasability (atopics).

Anesthetics↗
PubMed1985

Phosphodiesterase inhibition by Ro 20-1724 reduces hyper-IgE synthesis by atopic dermatitis cells in vitro.

Peripheral blood mononuclear leukocytes (MNL) from patients with atopic dermatitis spontaneously produce large amounts of IgE in vitro. These cells also show markedly elevated levels of cAMP phosphodiesterase (PDE) which may be responsible for the observed abnormal cAMP responsiveness. Treatment of atopic dermatitis MNL with varying concentrations of the cAMP PDE inhibitor Ro 20-1724 resulted in progressively decreasing amounts of IgE synthesis, statistically significant at the 10(-4) M and 10(-5) M concentrations. There was a close correlation between PDE inhibition and inhibition of IgE synthesis, r = 0.93, p less than 0.05. To define the cellular target of the drug, we used monoclonal antibodies directed toward MNL subsets (Lyt 3, OKT8, OKT4, monocyte-myeloid) in a modified "panning" method to perform experiments with purified subsets. With untreated subsets, removal of OKT4-positive cells significantly reduced IgE synthesis; readdition of OKT4-positive cells enhanced IgE synthesis. OKT8 cells and monocytes did not affect IgE synthesis. Pretreatment of T cell-depleted MNL with Ro 20-1724 resulted in significantly more inhibition of IgE synthesis than did pretreatment of T enriched cells prior to recombination with the reciprocal untreated subset and subsequent culture. Similarly, pretreatment of monocyte-depleted cells resulted in significantly more inhibition of IgE synthesis than pretreatment of monocyte-enriched cells prior to recombination and culture. The majority of the effect appeared to be mediated by a direct effect on the B cells. However, some inhibition of IgE synthesis was also achieved through pretreatment of T enriched cells. Since pretreatment of isolated suppressor/cytotoxic or helper/inducer T-cell subsets did not give the same degree of inhibition as with unfractionated T cells, a T-T interaction may be involved in this aspect. The imidazolidinone derivative, Ro 20-1724, significantly and consistently inhibited both the elevated cAMP phosphodiesterase activity and the elevated spontaneous IgE synthesis of MNL from patients with atopic dermatitis. These findings demonstrate a previously undescribed link between cAMP PDE levels and in vitro IgE synthesis.

4-(3-Butoxy-4-methoxybenzyl)-2-imidazolidinone↗
PubMed1985

Immunopharmacology of the atopic diseases.

The atopic conditions, atopic dermatitis, asthma, and allergic rhinitis, may arise as a result of infiltrating bone marrow-derived cells into skin or respiratory mucosae. Release of inflammatory factors from these cells could account for cutaneous vascular instability and pruritus in atopic dermatitis. Erythema and itch have been induced by experimental stress interviews and by blind food challenges. In the latter, increased plasma histamine was detected and correlated with cutaneous reactions. Basophils from patients with atopic dermatitis have increased histamine release after exposure to immunologic or nonimmunologic lectin stimuli. This increased releasability may relate to inadequate cyclic AMP regulation of cell function. We have found that leukocytes of patients with atopic dermatitis have elevated phosphodiesterase activity and consequently reduced intracellular cyclic AMP. Exposure of the cells to a phosphodiesterase inhibitor caused considerable reduction in histamine release. Similarly, exposure of atopic B lymphocytes to a phosphodiesterase inhibitor greatly reduced the high spontaneous IgE synthesis in mononuclear leukocyte cultures. Elevated leukocyte phosphodiesterase activity may also serve as a marker for the atopic diathesis. We have found elevated enzyme activity in umbilical cord blood from newborns with atopic parents, suggesting that this defect may relate to a genetically determined defect. These studies have provided insight into basic abnormalities associated with atopic dermatitis and the atopic diathesis. Defects of regulatory mechanisms in immune and inflammatory cells may help explain the seemingly disparate disorders of physiologic, pharmacologic, and immunologic systems in atopy.

Asthma↗
PubMed1985

Cyclic AMP-phosphodiesterase activity and histamine release in cord blood leukocyte preparations.

Atopic dermatitis, allergic rhinitis and asthma are a common group of diseases with a familial predisposition. At present there is no suitable predictive or diagnostic marker. Adults with atopic dermatitis or allergic respiratory disease have elevated mononuclear leukocyte cAMP-phosphodiesterase activity. This activity correlates closely with histamine release from basophils. We investigated newborn leukocyte phosphodiesterase activity and histamine release in umbilical cord blood. Phosphodiesterase activity was significantly elevated in cord blood leukocytes of 81 children with a positive history of atopy in first degree relatives, compared to 33 children with a negative history (p less than 0.025). In contrast to adults there was no correlation between phosphodiesterase activity and histamine release. Our studies suggest that elevated phosphodiesterase activity is a primary, genetically linked defect. Fetal basophils would appear to possess cytophilic IgE since they are capable of immunologically stimulated histamine release even without passive, in vitro IgE sensitization. In addition, there are functional differences between adult and cord blood basophils. Longitudinal studies may determine if elevated phosphodiesterase is predictive of atopic states.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1985

Basophil histamine release in atopic dermatitis and its relationship to disordered cyclic nucleotide metabolism.

Maximal histamine release (HR) from leucocytes, in response to Concanavalin A (Con A) was significantly higher in a group of 16 adults with moderate to severe atopic dermatitis (AD) when compared to 13 non-atopic adults. In a further 4 adults with AD, HR was similar to that in the normals, suggesting the existence of 'high releaser' and 'low releaser' subsets within the AD group. Leucocyte cyclic AMP phosphodiesterase (PDE) activity was significantly higher in the 'high releaser' group compared to the 'low releaser' and normal groups. High and low HR responses showed strong correlations with high and low PDE. Pre-treatment of leucocytes from 'high releasers' with the experimental PDE PDE inhibitor RO-20-1724 reduced the HR to normal levels. These findings suggest that increased histamine 'releasability' in AD is related to abnormalities in cyclic nucleotide regulation. No significant HR could be demonstrated in response to a range of concentrations of methacholine in 'high releaser' atopics and normals. Methacholine also did not affect HR in response to maximal Con A stimulation in 'high releaser' atopics. Basophil percentages within the leucocyte preparation and the histamine content per basophil, were not significantly different between the atopics and normals. Con A-stimulated histamine release did not correlate significantly with serum IgE levels.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1985

Enrichment of dog leukocyte subpopulations using density gradients.

Density gradient methods have been used for the enrichment of leukocyte subpopulations from human blood. We have adapted a three step method utilizing centrifugation on Hypaque-Ficoll (HF), double density HF (ddHF) and Percoll density gradients to separate lymphocytes, monocytes and basophils from dog blood. After HF separation, both Basenji-Greyhound (BG) and mongrel dogs had similar percentages of lymphocytes and monocytes, but BG dogs had significantly greater (p greater than 0.025) numbers of granulocytes. When cells from HF gradients were spun directly on Percoll, the presence of granulocytes decreased the purification of leukocyte subpopulations. An intervening separation on a ddHF gradient removed granulocytes without a selective loss of lymphocytes or monocytes. When cells from ddHF gradients were further separated on Percoll, 2 distinct cell layers resulted. Layer 1 was monocyte rich with 72.4 +/- 6.5% monocytes, 26.6 +/- 6.2% lymphocytes, and 0.8 +/- 1.8% granulocytes. Layer 2 was lymphocyte rich with 74.3 +/- 11.1% lymphocytes, 21.4 +/- 7.8% monocytes and 3.9 +/- 4.2% granulocytes. Viability as determined by Trypan blue exclusion was above 90%. Using cAMP-Phosphodiesterase (PDE) as a marker, higher PDE activity was present in the monocyte rich layer. This was similar to that reported in humans. Basophil numbers were enhanced by the use of a 1-step separation on a ddHF gradient. The percentage of basophils was increased 10-fold over baseline levels, with a viability of 90%. These techniques can be used to purify various canine leukocyte subpopulations and provide cells for biochemical analysis.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1985

Altered phosphorylation as a possible basis for cyclic nucleotide abnormalities in atopic dermatitis.

Exposure of normal mononuclear leukocytes (MNL) to histamine causes heterologous desensitization accompanied by beta adrenergic receptor alterations and increased cyclic AMP-specific phosphodiesterase (PDE) activity. We have demonstrated similar abnormalities in MNL from patients with atopic dermatitis (AD). Considering that these dual changes might be due to altered phosphorylation, we have studied cyclic AMP-dependent protein kinase (PK-A) in untreated and histamine-treated normal MNL and in AD cells. We found that basal or endogenous phosphorylative activity was two-fold higher in preparations from patients with AD. The activity ratios of protein kinase increased significantly in normal MNL after histamine exposure. In contrast, cells from patients with AD failed to show this increase. These findings correlate with similarly increased PDE activity after histamine stimulation of normal, but not AD cells. The increased PK-A activity in both atopic and histamine-desensitized MNL correlates with membrane receptor changes and elevated PDE activity. This enchaned phosphorylation may account for the varied physiological and immunological abnormalities that have been described in AD.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1984

Increased leukocyte sensitivity to phosphodiesterase inhibitors in atopic dermatitis: tachyphylaxis after theophylline therapy.

Previous studies have demonstrated elevated cyclic 3',5'-adenosine monophosphate specific phosphodiesterase (PDE) activity in mononuclear leukocytes (MNL) from patients with atopic dermatitis (AD) and with allergic respiratory disease. We have studied the effect of PDE inhibitors on MNL from normal subjects and from patients with AD. We measured PDE activity in MNL after in vitro exposure to Ro20-1724, theophylline, and isobutylmethylxanthine. The effect of PDE inhibitors was also measured in MNL of patients during and after oral theophylline therapy. There was a dose-response effect of Ro20-1724 on PDE activity of AD cells. This activity was significantly more inhibited than that in MNL of normal subjects or in MNL of theophylline-treated patients with AD. The inhibition pattern of PDE in MNL of treated patients with AD did not vary significantly from the pattern observed in MNL from normal patients. Two weeks after oral theophylline was stopped, the PDE activity in MNL was once again susceptible to in vitro inhibition. The relative resistance of MNL to PDE activity in normal subjects to in vitro PDE inhibitors may be due to the existence of different PDE enzyme forms or the presence of endogenous inhibitors. The clinical importance of the tachyphylaxis observed is uncertain, but our results suggest that intermittent dosing with PDE inhibitors may provide a therapeutic advantage in treatment of AD and other atopic diseases.

Administration, Oral↗
PubMed1984

Elevated umbilical cord blood leukocyte cyclic adenosine monophosphate-phosphodiesterase activity in children with atopic parents.

We found cyclic adenosine monophosphate-phosphodiesterase (cAMP-PDE) activity to be significantly elevated in the umbilical cord blood mononuclear leukocytes of forty-two children with one atopic parent (3.2 +/- 0.3) and in eighteen children with two atopic parents (4.2 +/- 0.7) as compared to twenty-two children with two nonatopic parents (1.9 +/- 0.2) (p less than 0.005). Among those newborns with one atopic parent, mean PDE activities were significantly elevated in cord blood cells regardless of whether only the father was atopic, thus eliminating the possibility of transplacental enzyme passage. Follow-up evaluations of twenty-four children, age 6 months or older, suggest that infants with elevated PDE activity at birth have an increased likelihood of developing dermatitis and/or "atopic features." Further long-term studies will determine the predictive value of newborn mononuclear leukocyte PDE activity.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1984

"Recurrent herpes zoster": an unproved entity?

Physicians sometimes misdiagnose recurrent zosteriform herpes simplex virus (HSV) skin infections as "zoster" or "recurrent zoster." Misdiagnosis can lead to inappropriate therapy with potentially harmful consequences, particularly in patients with ophthalmitis or immunosuppression, in which early institution of the correct antiviral therapy may be crucial. We report three patients who were originally misdiagnosed to have recurrent herpes zoster skin infections before we cultured HSV from their vesicles. We suggest: (1) that most recurrent zosteriform eruptions are caused by HSV; (2) that "recurrent zoster" has yet to be documented; and (3) that the diagnosis of "recurrent zoster" be reserved for those patients who have laboratory confirmation of recurrent varicella zoster (VZ). Viral culture or examination of vesicle contents by indirect immunofluorescent technic can provide definitive diagnosis of the etiology of a zosteriform eruption.

Adult↗
PubMed1984

Basic and clinical aspects of atopic dermatitis.

The history of atopic dermatitis is replete with many disparate theories. The most enduring is the allergic causation theory but definitive, convincing evidence remains elusive. Elevated IgE synthesis is well established and reflects abnormal immune regulation. The basic mechanism for the regulatory defect remains conjectural. Cellular immune functions, including delayed cutaneous hypersensitivity, in vitro lymphocyte transformation and chemotaxis are reduced in atopic dermatitis. However, these abnormalities fluctuate with the clinical condition and may be secondary phenomena. A number of physiologic and pharmacologic abnormalities in atopic dermatitis are not clearly understood. Recent studies of patients leukocytes have shown that the diminished cyclic AMP responses are a consequence of increased catabolism by elevated cyclic AMP-specific phosphodiesterase. This high enzyme activity correlates well with elevated IgE synthesis and histamine release by cultured leukocytes. Both of these functions can be reduced by phosphodiesterase inhibitors in vitro. These new investigations provide fresh insight into the pathogenesis of atopic dermatitis and offer possible new therapeutic approaches. Basic studies of biochemical abnormalities may help define the defective molecular site that accounts for the many immune and physiologic abnormalities that have been described in atopic dermatitis and the other atopic conditions.

Adolescent↗