Effects of recombinant plasminogen activator inhibitor type 1 on fibrinolysis in vitro and in vivo

A biologically active recombinant PAI-1 (rPAI-1) was evaluated for its effects on clot lysis in vitro and in vivo. At concentrations of 0.5 to 10 micrograms/ml, the rPAI-1 significantly prolonged the time to lysis of rabbit euglobulin clots both in the presence and absence of exogenous tissue plasminogen activator. To examine the effects of PAI in vivo, we infused rPAI-1 into conscious rabbits after i.v. injection of homogenized fibrin clots, and assessed fibrinolysis by measuring the appearance of d-dimer fibrin degradation products (FDP). Plasma fibrinolytic activity, PAI activity and antigen were also measured in plasma samples taken during and after infusion of rPAI-1. In control rabbits, endogenous fibrinolytic activity resulted in a significant and continual generation of FDP, reaching 32.6 +/- 13.6 ng/ml 90 minutes after fibrin injection. Infusion of 1, 2, or 5 micrograms/kg/min rPAI-1 led to dose dependent increases in PAI activity and antigen, while FDP levels at 90 minutes were only 8.8 +/- 2.9, 5.7 +/- 2.4, and 0.3 +/- 0.3 ng/ml, respectively. Complete inhibition of fibrinolysis was observed with 10 micrograms/kg/min rPAI-1. These studies directly demonstrate that increases in PAI-1 impair the fibrinolytic system, and support indirect observations of an association between elevated levels of this protein and thromboembolic diseases.

Purification and characterization of recombinant plasminogen activator inhibitor-1 from Escherichia coli

A recombinant form of plasminogen activator inhibitor-1 (rPAI-1) has been purified from lysates of pCE1200, a bacterial expression vector containing the full length PAI-1 gene, by utilizing sequential anion exchange and cation exchange chromatography on Q-Sepharose and S-Sepharose columns. Approximately 140 mg of rPAI-1, estimated at 98% purity on the basis of analytical high performance liquid chromatography, could be obtained from 200 g wet weight of cells. The purified protein exhibited a single Coomassie Blue-stainable band at the region of Mr = 42,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and an NH2-terminal amino acid sequence consistent with the expected translation product of the pCE1200 PAI-1 insert. The rPAI-1 rapidly inhibited single- and two-chain tissue plasminogen activators, as well as urokinase, with apparent second order rate constants in the range of 2-5 x 10(7) M-1 s-1. A specific activity measurement of 250,000 units/mg was calculated for the rPAI-1 based on its ability to inhibit the enzymatic activity of a single-chain tissue plasminogen activator. Stability studies showed that the activity of the rPAI-1 was very stable when stored at temperatures of 25 degrees C or lower, but decayed within hours when stored at 37 degrees C. Sodium dodecyl sulfate treatment, which partially activates the latent form of natural PAI-1, inactivated rPAI-1. These results show that the purified rPAI-1 produced from pCE1200 displays many of the properties associated with the biologically active form of natural PAI-1.

Basic fibroblast growth factor-like activity and receptors are expressed in a human glioma cell line

Basic fibroblast growth factor (bFGF), a potent mitogen and angiogenic peptide, has been examined as an autocrine regulator of glioma cell growth. The addition of purified bovine pituitary bFGF to an established human glioma cell line, SNB-19, doubled the density of these cells in chemically defined medium. Half-maximal stimulation occurred at 8.2 ng/ml (480 pM). Also, human recombinant bFGF (hr-bFGF) significantly enhanced the growth of SNB-19 cells in soft agar. SNB-19 cells expressed both high and low affinity binding sites for hr-bFGF. These cells expressed approximately 13,000 high affinity sites/cell (Kd = 16.6 +/- 1.7 pM) and 9.5 x 10(6) low affinity sites/cell (Kd = 61.2 +/- 4.1 nM). The results of cross-linking experiments with iodinated hr-bFGF demonstrated the presence of two bands with molecular masses of 145 and 130 kDa. High affinity receptors were also demonstrated in SNB-19 tumors grown in nude mice. SNB-19 cell extracts contained mitogenic activity that eluted from heparin-agarose with high salt (1.2-2 M NaCl) and exhibited many properties normally associated with authentic bFGF. This material cross-reacted with a monoclonal antibody to hr-bFGF, comigrated with hr-bFGF by Western blot analysis, competed with 125I-hr-bFGF in a radioreceptor assay, and stimulated SNB-19 cell growth. These results indicate that a human glioma cell line both expresses and utilizes a bFGF-like growth factor. Such a factor may be an important autocrine regulator of glioma cell growth and may also facilitate its neoplastic progression.

Effect of a monoclonal antibody to angiotensin II on hemodynamic responses to noradrenergic stimulation in pithed rats

A specific angiotensin II monoclonal antibody, KAA8, was used to examine the interaction between sympathetic function and angiotensin II in pithed rats. KAA8, at 5 or 50 mg/kg i.v., did not alter the mean blood pressure, cardiac output, total peripheral resistance, or heart rate responses to sympathetic neural stimulation (0.25-4.0 Hz) or to norepinephrine (0.3-3 micrograms/kg i.v.) but blocked significantly the hemodynamic responses to angiotensin II (0.03-1.0 microgram/kg i.v.) and to angiotensin III (0.3-10 micrograms/kg i.v.). KAA8 treatment also reduced the plasma immunoreactive angiotensin II from 2,880 +/- 475 pg/ml to an undetectable level. In contrast, captopril (5 mg/kg i.v.) and saralasin (10 or 50 micrograms/kg/min i.v.) inhibited the mean blood pressure and total peripheral resistance responses, but not the cardiac output and heart rate responses, to sympathetic neural stimulation and to norepinephrine. These results, which confirm previous findings by Kaufman and Vollmer (Kaufman LJ, Vollmer RR: Endogenous angiotensin II facilitates sympathetically mediated hemodynamic responses in pithed rats. J Pharmacol Exp Ther 1985;235:128-134), demonstrate that angiotensin II selectively potentiates the sympathetic vascular function in the pithed rat. However, our results suggest that circulating angiotensin II does not appear to interact with the sympathetic vascular function. It is speculated that in the pithed rat the sympathetic vascular response is enhanced by vascular-formed angiotensin II.

Monoclonal antibodies directed against basic fibroblast growth factor which inhibit its biological activity in vitro and in vivo

A panel of four murine monoclonal IgG1 antibodies (mAbs) to a recombinant form of basic fibroblast growth factor (bFGF) was produced using somatic cell fusion techniques. Non-linear regression analysis of radioimmunoassay data for each mAb yielded the following dissociation constants (nM) for their interactions with bFGF: DE6 (0.822); AF11 (2.0); FE8 (2.31); and DG2 (20.0). One of the mAbs, DG2, was identified as a bFGF neutralizing antibody on the basis of its ability to inhibit, in vitro, the binding of [125I]-bFGF to high and low affinity bFGF sites on cultured baby hamster kidney cells and bFGF-induced [3H]-thymidine incorporation in cultured 3T3 cells, and in vivo, the angiogenic response to bFGF in a rat kidney capsule model of angiogenesis. The other mAbs displayed varying inhibitory activities in these assays. These mAbs, particularly DG2, may be well suited for a number of applications in bFGF research including immunoassays, immunohistochemical studies, and as functional antagonists of bFGF for examining its role in physiological processes such as reproduction, growth, and development.

Tissue plasminogen activator-induced secretion of type-1 plasminogen activator inhibitor in cultured human fibroblasts

Tissue plasminogen activator (t-PA) regulation of type-1 plasminogen activator inhibitor (PAI-1) secretion by WI-38 human fibroblasts was investigated utilizing a specific ELISA to measure PAI-1 antigen levels. Incubation of confluent fibroblasts with t-PA in serum-free medium resulted in a concentration and time-dependent increase in the secretion of PAI-1, with the maximum response (a two-fold increase) observed following a 4 hour incubation with 0.1 microM t-PA. This t-PA effect was reduced by cycloheximide, suggesting that the involvement of specific protein synthesis, and by inhibitors of t-PA's enzymatic activity, suggesting a requirement for a free catalytic site. The t-PA effect could not be attributed to endotoxin contamination. Increased levels in cell-associated PAI-1 were also detected following incubation of fibroblasts with t-PA. This previously undescribed effect, although seen at relatively high concentrations of t-PA, may have important biological implications.

Antihypertensive mechanism of captopril in renal hypertensive rats: studies with a nonpeptide angiotensin II receptor antagonist and an angiotensin II monoclonal antibody

The validity of using EXP6803, a nonpeptide angiotensin II (AII) receptor antagonist, and KAA8, an AII monoclonal antibody, as specific tools for studying the physiology of AII has been established previously. In this study, we used these specific probes to examine the role of blocking AII formation in the antihypertensive effect of captopril in conscious renal artery-ligated rats (RALRs), a high renin, renal hypertensive model. Mean arterial pressure and plasma renin activity in a typical group of RALRs averaged 175 +/- 5 mm Hg and 28.2 +/- 6.2 ng of angiotensin 1 per ml/hr (n = 6), respectively. The antihypertensive effect of captopril (3 mg/kg i.v.) was determined in RALRs given either EXP6803 (30 mg/kg + 2 mg/kg/min i.v.) or KAA8 (10 mg + 1 mg/min i.v. per rat) with the corresponding vehicle-treated RALRs. These doses of EXP6803 and KAA8 were very effective in blocking the pressor response to AII but not to norepinephrine or vasopressin in RALRs. Captopril decreased mean arterial pressure by 44 +/- 2 and 53 +/- 8 mm Hg in the groups treated with the vehicles of EXP6803 (n = 5) and KAA8 (n = 5), respectively. In the presence of EXP6803 (n = 5) or KAA8 (n = 5), the antihypertensive effect of captopril was almost or totally abolished. Indomethacin did not alter the antihypertensive effect of captopril. These results suggest that the antihypertensive effect of captopril in conscious RALRs is due mainly to the blockade of AII formation. Furthermore, circulating AII rather than locally formed AII appears to play a major role in maintaining hypertension in hypertension in RALRs.

Binding of tissue plasminogen activator to cultured human fibroblasts

The binding of 125I-labeled, one-chain tissue plasminogen activator (t-PA) by WI-38 cultured human lung fibroblasts was investigated. Binding of t-PA to WI-38 monolayers was specific, saturable and temperature dependent. One and two-chain t-PAs were comparable in their ability to compete with 125I-labeled, one-chain t-PA for binding to fibroblasts, while no inhibition of binding was observed with a 500-fold molar excess of urokinase. Studies with various compounds suggest that neither the catalytic site, the fibrin binding site, nor the carbohydrate moieties on t-PA are involved in its binding to WI-38 cells. At higher temperatures, the amount of cell-bound 125I-t-PA that was removed by either incubation in binding buffer containing an excess of unlabeled t-PA, or by brief treatment with acidic buffer, was small (approximately 20%) suggesting that much of the t-PA is internalized. Electrophoretic analysis of extracts prepared from cells that had been incubated with 125I-t-PA revealed the presence of a major band of 70,000 Mr, which corresponds to intact t-PA. Our results suggest that WI-38 fibroblasts are capable of binding and internalizing t-PA, and that these processes involve a receptor site specific for t-PA.

Monoclonal antibodies to tissue-type plasminogen activator which prolong its clearance in vivo

Three murine monoclonal antibodies to tissue-type plasminogen activator (t-PA) were evaluated for their effects on the binding of iodinated t-PA to cultured human hepatoma cells (Hep G2), and on extending the half-life of t-PA injected into rabbits. Two of the antibodies, AE5 and EG2, significantly inhibited t-PA binding in vitro, and extended the in vivo half-life of t-PA four to five-fold. A third antibody, BA10, which had a much smaller inhibitory effect on t-PA binding, had no influence in extending t-PA's half-life. MOPC-21, a control antibody not directed to t-PA, had no effect on either test. Our results are the first to correlate different compounds' effects on t-PA binding with their ability to retard t-PA clearance in vivo, and provide additional evidence for the importance of a liver cell receptor in the t-PA clearance process.

The Mitrofanoff principle for continent urinary diversion

A continent urinary diversion was formed for 16 patients using the Mitrofanoff principle for continence. As originally described, this system used the appendix tunnelled into the bladder to form a continent catheterisable vesicostomy. We have expanded the technique and have used all available narrow tubes as continent conduits (ureter 10 cases, appendix 5, Fallopian tube 1). The urine container was made of large and small intestine and bladder in several combinations. The system has been very satisfactory: 14 patients were continent and able to catheterise; 1 required a revision to achieve continence and 1 awaits revision; 3 patients required revision procedures for stricture.

Characterization of a panel of monoclonal antibodies against human tissue-type plasminogen activator

Five murine monoclonal antibodies have been produced against the 1-chain form of human tissue plasminogen activator (t-PA). Affinity constants, calculated from data generated in a solid phase radioimmunoassay, ranged from 4.9 x 10(8)M-1 to 2.3 x 10(9) M-1 for these antibodies. This panel was classified into three groups based on the antibodies' effects on both the plasminogen activation and amidolytic activities of t-PA: complete inhibitors (CD2), partial inhibitors (DB10), and those with limited effects (AE5, BA10 and EG2). This same pattern for the five antibodies was observed in an assay measuring the binding of 125I-t-PA to its fast-acting inhibitor, PAI-1. It is concluded that this panel of antibodies defines at least three domains on the t-PA molecule, including its catalytic site.

Characterization of the functional antagonism and antihypertensive activity displayed by a monoclonal antibody to angiotensin II

In the present study, we have characterized the specificity and potency of KAA8, a monoclonal antibody displaying a high affinity for angiotensin II (AII), as a functional antagonist of AII in vitro and in vivo. In addition, we have studied its antihypertensive effect in the awake renal artery-ligated rat, whose elevated levels of plasma renin activity and sensitivity to captopril and saralasin define it as a renin-angiotensin system-dependent hypertensive model. Our results utilizing isolated rabbit aorta strips and pithed rats suggest that KAA8 is a specific AII functional antagonist because it selectively inhibited the AII response in these models without altering the effects of norepinephrine and vasopressin. In renal artery-ligated rats, KAA8, at 15 mg/kg i.v., decreased mean blood pressure from 148 +/- 3 to 119 +/- 4 mm Hg at 10 min postinjection (n = 9) and greatly inhibited the pressor response to AII but not to vasopressin. In contrast, a control immunoglobulin G1 molecule did not change mean blood pressure or influence the pressor effect of AII in this model. Pretreatment with captopril or saralasin, but not prazosin or hydralazine, blocked the antihypertensive effect of KAA8 in these renal hypertensive rats. These results suggest that the antibody KAA8 displays specific functional AII antagonism and, as such, may represent a specific probe for studying the physiologic roles of AII.

A monoclonal anti-idiotypic antibody which mimics angiotensin II in inducing a population of anti-hormone antibodies

IG12, a syngeneic monoclonal anti-idiotypic antibody, was raised against an idiotype on a monoclonal antibody, ICH2, with specificity for the octapeptide hormone angiotensin II (AII). Competitive radioimmunoassays, and ELISAs utilizing AII antiserum raised in different species (rats and rabbits), indicate that IG12 detects a private idiotypic determinant at or near the paratopic region of the ICH2 combining site. Immunization of syngeneic mice with either IG12 or IG12 coupled to keyhole limpet hemocyanin induced a population of anti-anti-idiotypic antibodies that shared two properties with ICH2: the binding of AII and the binding to IG12. Antibodies from these anti-anti-idiotypic populations were also partially active in inhibiting the interaction between AII and ICH2. To our knowledge, this is the first demonstration of a monoclonal anti-idiotypic antibody mimicking a physiological hormone in inducing a population of anti-hormone antibodies.

Functional antagonism by monoclonal antibody to digoxin in the guinea-pig atria

A monoclonal antibody with a high affinity for digoxin (Ka = 1.14 X 10(9) M) was produced by somatic cell fusion. This antibody, designated 35/6.1, displayed little or no cross reactivity with other steroids. In the guinea-pig atria, 35/6.1 antagonized functionally the positive inotropic effect of digoxin but did not alter that of isoproterenol. Our results suggest that this monoclonal antibody may represent a useful probe for studying the physiological role of the putative endogenous digoxin-like factor in various pathophysiological conditions.

Monoclonal antibodies to angiotensin II

Three hybridomas producing monoclonal antibodies to angiotensin II were generated using somatic cell fusion techniques. Dissociation constants, determined by Scatchard analysis of radioimmunoassay data, were 9.3 X 10(-10) M, 1.5 X 10(-9) M and 1.8 X 10(-8) M for antibodies KAA8, ICH2 and ICA10, respectively. The antibodies exhibited various degrees of cross-reactivity towards peptide metabolites of angiotensin II, but minimal cross-reactivity towards antagonists created by substituting the hormone at both the amino and carboxy terminus. In contrast to a rabbit polyclonal angiotensin II antibody preparation, the three monoclonal antibodies competed effectively with angiotensin receptors on rat adrenal cortical microsomes for hormone binding. These antibodies may have broad utility for a number of applications in angiotensin II research.

The presentation and treatment of delusional parasitosis: a dermatological perspective

A postal survey of dermatologists identified 365 patients with a presumptive diagnosis of delusional parasitosis. One hundred and forty-four dermatologists had seen at least 1 such patient in the previous 5 years and 78 were current. The data provided on 53 patients who met the study criteria were examined in more detail. Racial origin, marital status and age at presentation varied widely. Females predominated in the older age-groups, but there was an equal sex distribution under the age of 50. Abnormal personality traits were commonly identified, especially of the obsessional type. Physical disorders associated with pruritus co-existed in a substantial minority. Previous dermatological and psychiatric disorders were uncommon and non-specific. The disorder was often, though not invariably, of long duration. Relatively few patients were successfully referred to psychiatrists. Dermatologists often treated the disorder effectively, especially when neuroleptic agents were employed. Pimozide appeared to be particularly helpful in many patients.

Production of idiotypic and anti-idiotypic antibodies by BALB/c mice in response to immunizations with glucagon, vasopressin, or insulin: supporting evidence for the network concept

After immunizations with glucagon or vasopressin, either conjugated to keyhole limpet hemocyanin or adsorbed to polyvinylpyrrolidone, both anti-hormone and anti-receptor activities were detectable in the serum of injected mice. Anti-hormone activity was identified by ELISA techniques; anti-receptor activity, by determining the ability of serum samples to compete with labeled hormone for glucagon or vasopressin receptors on rat liver plasma membranes. Anti-receptor activity appeared only after the peak anti-hormone response to each immunogen had been established, and required intensive immunizations (six to nine monthly injections). The presence of anti-idiotypic antibodies in serum samples containing glucagon or vasopressin anti-receptor activity was confirmed by demonstrating selective binding of such samples to corresponding rabbit idiotypic antibodies. Serum from mice immunized with insulin also contained anti-hormone activity, as determined by ELISA, and anti-receptor activity, as determined by noting insulin-mimicking properties in stimulating glucose transport in rat adipocytes. The anti-insulin receptor activity developed after only one boost with the hormone. These results are consistent with Jerne's network hypothesis in that the glucagon, vasopressin, and insulin anti-receptor activity may be attributed to antibodies produced in mice as part of an idiotypic-anti-idiotypic network.

Production of idiotypic and anti-idiotypic antibodies by BALB/c mice in response to immunizations with glucagon, vasopressin, or insulin: supporting evidence for the network concept

After immunizations with glucagon or vasopressin, either conjugated to keyhole limpet hemocyanin or adsorbed to polyvinylpyrrolidone, both anti-hormone and anti-receptor activities were detectable in the serum of injected mice. Anti-hormone activity was identified by ELISA techniques; anti-receptor activity, by determining the ability of serum samples to compete with labeled hormone for glucagon or vasopressin receptors on rat liver plasma membranes. Anti-receptor activity appeared only after the peak anti-hormone response to each immunogen had been established, and required intensive immunizations (six to nine monthly injections). The presence of anti-idiotypic antibodies in serum samples containing glucagon or vasopressin anti-receptor activity was confirmed by demonstrating selective binding of such samples to corresponding rabbit idiotypic antibodies. Serum from mice immunized with insulin also contained anti-hormone activity, as determined by ELISA, and anti-receptor activity, as determined by noting insulin-mimicking properties in stimulating glucose transport in rat adipocytes. The anti-insulin receptor activity developed after only one boost with the hormone. These results are consistent with Jerne's network hypothesis in that the glucagon, vasopressin, and insulin anti-receptor activity may be attributed to antibodies produced in mice as part of an idiotypic-anti-idiotypic network.

On the mechanism of isoproterenol-induced desensitization of adenylate cyclase in cultured differentiated hepatocytes

The adenylate cyclase of cultured differentiated RL-PR-C hepatocytes is desensitized to 1-isoproterenol by exposure to this beta-agonist. Virtually complete desensitization occurred by 60 min (intact cells) or 30 min (isolated plasma membranes). Isoproterenol was maximally effective at 10 micrometers, although substantial desensitization occurred at isoproterenol concentrations as low as 10 nM. Protein synthesis was not required for desensitization. Recovery from desensitization under tissue culture conditions was only 25% complete by 24 h. Maximum desensitization was accompanied by only a modest 35% decrease in binding sites (as determined by binding assays with [3H]dihydroalprenolol), with no change in binding affinity. Adenylate cyclase desensitized to 1-isoproterenol responded normally to guanine nucleotides and to fluoride, suggesting that the regulatory and catalytic proteins were not the sites of the desensitization "defect'. Using N-ethylmaleiimide to inactive the regulatory and catalytic proteins, and dicyclohexylcarbodiimide to inactivate the beta-adrenergic receptor, of intact hepatocytes, various heterologous cell fusion hybrids were produced, and their adenylate cyclases tested for responsiveness to 1-isoproterenol; only hybrids containing "desensitized' receptor failed to respond to isoproterenol. These results suggest that the mechanism of desensitization to isoproterenol involves only the receptor component of the receptor-regulatory protein(s)-adenylate cyclase complex, and that the receptors are reduced in number and/or ability to interact with the regulatory protein as a result of the desensitization process.

Interaction of guanine nucleotides with adenylate cyclase in normal and spontaneously transformed RL-RP-C cloned rat hepatocytes

Spontaneous transformation of RL-PR-C hepatocytes leads to alterations in the adenylate cyclase complex which include a lower than normal basal level of activity, a loss of sensitivity to exogenous GTP, and a decreased sensitivity to isoproterenol. Both normal and transformed membranes possess substantial GTPase activity. Treatment of transformed hepatocyte membranes with either isoproterenol plus GMP or with cholera toxin, under conditions that displace tightly bound GDP, restored the GTP effect on adenylate cyclase, and eliminated the lag in the activation by guanyl-5'-yl-imidodiphosphate. Such pretreatment also enhanced guanine nucleotide effects on the adenylate cyclase of normal hepatocytes. These results are explainable on the basis that transformation increases adenylate cyclase-associated GTPase activity, and increases occupancy of nucleotide regulatory sites by inactive or inhibitory guanine nucleotides, e.g., GDP. Seemingly, both catecholamines and cholera toxin promote an exchange reaction at the regulatory sites, resulting in clearance of these sites of inhibitory nucleotides.

Restoration of glucagon responsiveness in spontaneously transformed rat hepatocytes (RL-PR-C) by fusion with normal progenitor cells and rat liver plasma membranes

Spontaneously transformed RL-PR-C rat hepatocytes, unlike their normal differentiated progenitor cells, are insensitive to glucagon, although seemingly possessing large numbers of glucagon receptors and although retaining guanyl nucleotide regulatory protein-adenylate cyclase [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1] system that responds to catecholamines, cholera toxin, and fluoride ions. Biochemical fusions between normal RL-PR-C hepatocytes or purified rat liver plasma membranes (whose adenylate cyclases were previously irreversibly inactivated with N-ethylmaleimide) with spontaneously transformed hepatocytes produced hybrids whose basal and fluoride-stimulated adenylate cyclase activities reflected those of the parental transformed cells but that now responded to glucagon. Using cholera toxin-catalyzed ADP-riboxylation of transformed hepatocytes to mark their guanyl nucleotide regulatory protein, fusiong such cells with N-ethylmaleimide-treated normal hepatocytes, and examining glucagon stimulation of adenylate cyclase activity in fusion hybrids produced results suggesting that the regulatory protein of the transformed cells is functionally normal. In fusion experiments between N-ethylmaleimide-treated hepatocytes and igeon erythrocytes, we found that normal, but not transformed, hepatocytes were effective in conferring glucagon sensitivity upon erythrocytes. Glucagon binding data revealed that, whereas normal RL-PR-C hepatocytes have two independent classes of binding sites, one of higher and the other of lower affinity, transformed cells possess only the low-affinity receptors. From these and previous observations, it is possible to conclude that the insensitivity of spontaneously transformed RL-PR-C hepatocytes to glucagon is due to the loss, during the transformation process, of the high-affinity glucagon receptor.

Successful treatment with pimozide of delusional parasitosis

An introduction to the concept of delusional parasitosis is presented. The persistent and refractory nature of the condition is emphasized. A case history is described in which a 67-year-old spinster, with classical symptoms of this condition, responded extremely favourably to simply administered pharmacotherapy. The authors allude to five similar patients also treated successfully by the same method. It is suggested that dermatologists might profitably treat this condition without recourse to psychiatric referral, which can often be counter-productive.

Monosymptomatic hypochondriacal Psychosis: Presentation and Treatment

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Physiological dependence on, and symptoms of withdrawal from, chlormethiazole

The uses of chlormethiazole (Heminevrin) are briefly mentioned. Differing views of its potential for producing dependence are discussed. The consensus opinion is taken to be that a risk of psychological dependence does exist, but only one case has appeared in the medical literature to date of physiological dependence on chlormethiazole, with withdrawal symptoms. This case is re-examined. A second case is described in which the features of increasing dosage and withdrawal were followed by confusion, disorientation, delusions, hallucinations and muscular spasm and coarse jerking. This is taken as confirmation of the potential of chlormethiazole to produce physiological dependence. Some personal opinions of the author regarding indications for use and incidence of abuse are briefly mentioned.