Loss-of-Function Myeloperoxidase Mutations Are Associated with Increased Neutrophil Counts and Pustular Skin Disease

The identification of disease alleles underlying human autoinflammatory diseases can provide important insights into the mechanisms that maintain neutrophil homeostasis. Here, we focused our attention on generalized pustular psoriasis (GPP), a potentially life-threatening disorder presenting with cutaneous and systemic neutrophilia. Following the whole-exome sequencing of 19 unrelated affected individuals, we identified a subject harboring a homozygous splice-site mutation (c.2031-2A>C) in MPO. This encodes myeloperoxidase, an essential component of neutrophil azurophil granules. MPO screening in conditions phenotypically related to GPP uncovered further disease alleles in one subject with acral pustular psoriasis (c.2031-2A>C;c.2031-2A>C) and in two individuals with acute generalized exanthematous pustulosis (c.1705C>T;c.2031-2A>C and c.1552_1565del;c.1552_1565del). A subsequent analysis of UK Biobank data demonstrated that the c.2031-2A>C and c.1705C>T (p.Arg569Trp) disease alleles were also associated with increased neutrophil abundance in the general population (p = 5.1 × 10^-6 and p = 3.6 × 10^-5, respectively). The same applied to three further deleterious variants that had been genotyped in the cohort, with two alleles (c.995C>T [p.Ala332Val] and c.752T>C [p.Met251Thr]) yielding p values < 10^-10. Finally, treatment of healthy neutrophils with an MPO inhibitor (4-Aminobenzoic acid hydrazide) increased cell viability and delayed apoptosis, highlighting a mechanism whereby MPO mutations affect granulocyte numbers. These findings identify MPO as a genetic determinant of pustular skin disease and neutrophil abundance. Given the recent interest in the development of MPO antagonists for the treatment of neurodegenerative disease, our results also suggest that the pro-inflammatory effects of these agents should be closely monitored.

Interleukin-1β biosynthesis inhibition reduces acute seizures and drug resistant chronic epileptic activity in mice

Experimental evidence and clinical observations indicate that brain inflammation is an important factor in epilepsy. In particular, induction of interleukin-converting enzyme (ICE)/caspase-1 and activation of interleukin (IL)-1β/IL-1 receptor type 1 axis both occur in human epilepsy, and contribute to experimentally induced acute seizures. In this study, the anticonvulsant activity of VX-765 (a selective ICE/caspase-1 inhibitor) was examined in a mouse model of chronic epilepsy with spontaneous recurrent epileptic activity refractory to some common anticonvulsant drugs. Moreover, the effects of this drug were studied in one acute model of seizures in mice, previously shown to involve activation of ICE/caspase-1. Quantitative analysis of electroencephalogram activity was done in mice exposed to acute seizures or those developing chronic epileptic activity after status epilepticus to assess the anticonvulsant effects of systemic administration of VX-765. Histological and immunohistochemical analysis of brain tissue was carried out at the end of pharmacological experiments in epileptic mice to evaluate neuropathology, glia activation and IL-1β expression, and the effect of treatment. Repeated systemic administration of VX-765 significantly reduced chronic epileptic activity in mice in a dose-dependent fashion (12.5-200 mg/kg). This effect was observed at doses ≥ 50 mg/kg, and was reversible with discontinuation of the drug. Maximal drug effect was associated with inhibition of IL-1β synthesis in activated astrocytes. The same dose regimen of VX-765 also reduced acute seizures in mice and delayed their onset time. These results support a new target system for anticonvulsant pharmacological intervention to control epileptic activity that does not respond to some common anticonvulsant drugs.

Aminaphtone in the treatment of pseudophakic cystoid macular edema: a case report

PURPOSE

Cystoid macular edema (CME) following cataract surgery has been recognized for over 50 years as an important cause of suboptimal post-operative vision. The incidence of CME varies widely, but is likely in the range of 1-2% using modern cataract extraction techniques. We report the case of resolution of post-operative CME after treatment with aminaphtone 75 mg three time a day for one month.

METHODS

A 74-year-old causasian woman presented with reduced vision in the left eye after one month from uneventful cataract phacoemulsification. She underwent a complete ophthalmological examination comprehensive of spectral domain optical coherence tomography (SD-OCT) which showed CME and a central foveal thickness (CFT) of 703 micron. The patient was treated with aminaphtone for one month.

RESULTS

CME disappeared, the CFT was within normal limits when aminaphtone was ceased, and best corrected visual acuity was 20/20 at the end of the treatment.

CONCLUSION

Aminaphtone is a novel proposal in the treatment of pseudophakic cystoid macular edema.

Stabilization of the nitric oxide (NO) prodrugs and anticancer leads, PABA/NO and Double JS-K, through incorporation into PEG-protected nanoparticles

We report the stabilization of the nitric oxide (NO) prodrugs and anticancer lead compounds, PABA/NO (O(2)-{2,4-dinitro-5-[4-(N-methylamino)benzoyloxy]phenyl} 1-(N,N-dimethylamino)diazen-1-ium-1,2-diolate) and "Double JS-K" 1,5-bis-{1-[(4-ethoxycarbonyl)piperazin-1-yl]diazen-1-ium-1,2-diol-2-ato}-2,4-dinitrobenzene, through their incorporation into polymer-protected nanoparticles. The prodrugs were formulated in block copolymer-stabilized nanoparticles with sizes from 220 to 450 nm by a novel rapid precipitation process. The block copolymers, with polyethylene glycol (PEG) soluble blocks, provide a steric barrier against NO prodrug activation by glutathione. Too rapid activation and NO release has been a major barrier to effective administration of this class of compounds. The nanoparticle stabilized PABA/NO are protected from attack by glutathione as evidenced by a significant increase in time taken for 50% decomposition from 15 min (unformulated) to 5 h (formulated); in the case of Double JS-K, the 50% decomposition time was extended from 4.5 min (unformulated) to 40 min (formulated). The more hydrophobic PABA/NO produced more stable nanoparticles and correspondingly more extended release times in comparison with Double JS-K. The hydrophobic blocks of the polymer were either polystyrene or polylactide. Both blocks produced nanoparticles of approximately the same size and release kinetics. This combination of PEG-protected nanoparticles with sizes appropriate for cancer targeting by enhanced permeation and retention (EPR) and delayed release of NO may afford enhanced therapeutic benefit.

[Effect of paraaminobenzoic acid on interleukine-6 production in patients with herpetic keratitis]

The purpose of the study was to compare the effect of para-aminobenzoic acid (PABA) (actipol) on tear interleukin-6 (IL-6) levels in patients with herpetic keratitis and in peripheral blood cells of volunteers in vitro. Enzyme immunoassay was used to measure lacrimal fluid IL-6 levels in the actipol and acyclovir groups before and 1, 2, 3, 4, and 7-8 days after therapy and after clinical recovery in 30 patients with herpetic keratitis. A control group comprised apparently healthy volunteers (n=13, 26 eyes) who used actipol instillations into the conjunctival sac 4-5 times a day. The spontaneous production of cytokines and their production in response to the induction with different PABA concentrations (0.001, 0.01, 0.1, and 10 microkg/ml) were studied on peripheral blood cells taken from 9 volunteers. In the patients with herpetic, actipol was found to reduce and normalize tear IL-6 levels while acyclovir failed to produce this effect. In the healthy individuals, actipol did not affect IL-6 production in the anterior segment of the eye. All study PABA concentrations exerted a modulating effect on the production of IL-6 in the peripheral blood cells in vitro.

A novel in vitro percutaneous penetration model: evaluation of barrier properties with p-aminobenzoic acid and two of its derivatives

PURPOSE

The objective of this study was to evaluate the utility of a stratum corneum substitute (SCS) as a novel in vitro percutaneous penetration model. The SCS consists of synthetic stratum corneum (SC) lipids (cholesterol, free fatty acids, and specific ceramides) applied onto a porous substrate. The composition, organization, and orientation of lipids in the SCS bear high resemblance to that of the intercellular barrier lipids in SC.

METHODS

The barrier integrity of the SCS was evaluated by means of passive diffusion studies, using three model compounds with different lipophilicities. The effects of lipid layer thickness, permeant lipophilicity, and altered lipid composition on the barrier properties were investigated, using isolated human SC as a control sample.

RESULTS

For all three model compounds, the permeability characteristics of the SCS with a 12-mum-thick lipid layer closely resemble those of human SC. Modification of the lipid composition, generating an SCS that lacks the characteristic long periodicity phase as present in SC, was accompanied by a 2-fold increased permeability.

CONCLUSIONS

The SCS offers an attractive tool to predict solute permeation through human skin. Moreover, as its lipid composition can be modified, they may also serve as a suitable screening model for diseased skin.

Double-blind study on the effects of topical anesthesia on laryngeal secretions

The application of topical anesthesia to the oropharynx is a common clinical practice during oral and nasal laryngoscopy. Clinically, questions have been raised about whether topical anesthesia alters laryngeal secretions, which distorts clinical impressions. A double-blind, placebo controlled design was employed to address this issue. Ten premenopausal women with healthy vocal folds and 10 premenopausal women with phonotraumatic lesions underwent oral videolaryngoscopic examinations on subsequent days under both anesthesia and placebo conditions, in counterbalanced order. Video segments were rated by three judges. Dependent variables were balling and pooling of secretions, as previously described in the literature. Statistical analyses failed to reveal any clear effect of topical anesthesia on either secretion balling or pooling for the collapsed data set, but one cannot exclude changes in individual cases. Moreover, there was no evidence that secretions were differentially affected by anesthesia across subject groups. Null results in this data set replicate and extend previously reported findings by other authors. An incidental but potentially interesting finding was that the order of treatment condition (anesthesia versus placebo first) seemed relevant for secretions: Subjects who received the anesthesia condition first tended to show more secretion balling in general, as compared with subjects who received the placebo condition first. Speculation is entertained regarding possible physiological pathways for these incidental findings, which could be relevant for some clinical practice.

[Clinical investigation on the effect of intravesical instillation of antifibrinolytic agents with bacillus Calmette-Guerin on preventing bladder cancer recurrence]

OBJECTIVE

To investigate the effect of intravesical instillation of antifibrinolytic agents with bacillus Calmette-Guerin (BCG) on preventing recurrence of superficial bladder transitional cell carcinoma (BTCC) after surgical management.

METHODS

A total of 326 cases of superficial BTCC undergoing transurethral resection of bladder tumor (TURBT) or partial cystectomy were divided into 5 groups. Then the different dosage BCG with or without antifibrinolytic agents was regular instilled into bladders (once a week, then once a month after 6 times). Group A including 66 cases received intravesical instillation of 100-120 mg BCG plus 100 mg para-aminomethyl benzoic acid (PAMBA). Group B including 64 cases: instillation of 50-60 mg BCG plus 100 mg PAMBA; Group C including 65 cases: 100-120 mg BCG plus 2.0 g epsilon-aminocaproic acid (EACA); Group D including 64 cases: 50-60 mg BCG plus 2.0 g EACA; Group E (control group) including 67 cases: 100-120 mg BCG. All the cases had been followed up for 4 to 69 months (mean, 28.5 months). Not only was cystoscopy performed every 3 months, but also biopsy was carried out to identify recurrence when necessary. Side effect was recorded after instillation.

RESULTS

The rate of tumor recurrence of Group A, Group B, Group C and Group D was 12%, 10%, 9%, 9% respectively, which was significantly lower than that of Group E (30%) (chi(2) = 5.699, 6.818, 7.380, 7.867, P = 0.017, 0.009, 0.007, 0.005). And there was no significant difference of tumor recurrence rate between Group A and Group B or between Group C and Group D (Group A and Group C: high dosage BCG plus antifibrinolytic agents, while Group B and Group D: low dosage BCG plus antifibrinolytic agents) (P > 0.05). But the side effects developing in Group B and Group D after BCG instillation were less than those in Group A and Group C.

CONCLUSIONS

The efficacy of BCG on prevention the recurrence of superficial BTCC can be enhanced when combined with antifibrinolytic agents. Even if the dosage of BCG was reduced by half, the efficacy didn't changed. A new approach of low dosage BCG plus antifibrinolytic agents is recommended in the prophylaxis of recurrence of bladder cancer.

Bacterially synthesized folate and supplemental folic acid are absorbed across the large intestine of piglets

A large pool of folate exists in the large intestine of humans. Preliminary evidence, primarily in vitro, suggests that this folate may be bioavailable. The purpose of this study was to test the hypothesis that supplemental folic acid and bacterially synthesized folate are absorbed across the large intestine of piglets. The pig was used as an animal model because it resembles the human in terms of folate absorption, at least in the small intestine. A tracer of [3H]-folic acid or [3H]-para-aminobenzoic acid ([3H]-PABA), a precursor of bacterially synthesized folate, was injected into the cecum of 11-day-old piglets. Feces and urine were collected for 3 days. Thereafter, piglets were killed, and livers and kidneys harvested. [3H]-Folate was isolated from biological samples by affinity chromatography using immobilized milk folate binding proteins and counted using a scintillation counter. In piglets injected with [3H]-folic acid, the feces, liver, urine and kidneys accounted for 82.1%, 12.3%, 3.9% and 1.7% of recovered [3H]-folate, respectively. In piglets injected with [3H]-PABA, the amount of recovered bacterially synthesized folate in the feces, liver and urine was 85.1%, 0.4% and 14.6%, respectively. Twenty-three percent and 13% of tritium were recovered in samples examined (liver, kidney, fecal and urine) from piglets injected with [3H]-folic acid and [3H]-PABA, respectively. Using our estimates of [3H]-folic acid absorption and the total and percent monoglutamyl folate content of piglet feces, we predict that at least 18% of the dietary folate requirement for the piglet could be met by folate absorption across the large intestine.

Tongue entrapment in an aluminum juice can

Tongue entrapment in bottles and cans is rare, but occurs. The following is a case report of a 10-year-old female who got her tongue entrapped in an aluminum juice can. The anatomy of the tongue, complications from injury, and a proposed removal procedure are described.

The management of Peyronie's disease

Peyronie's disease has no known cause; recent understanding of the molecular mechanisms involved and the development of an animal model will aid the medical management of early disease. The medical management of chronic disease is futile as the delicate tunical architecture cannot regenerate. Surgical correction of the penile deformity is required in a minority of patients, and a choice lies between a Nesbit operation and a plaque incision and venous patch in patients who are concerned with penile shortening.

Effect of dietary p-aminobenzoic acid on murine Plasmodium yoelii infection

Plasmodia species, unlike humans, can utilize p-aminobenzoic acid (PABA) for the de novo generation of folate. Plasmodial enzymes for the synthesis of PABA via the shikimate pathway are being investigated as novel targets for malaria chemotherapy. We show that, despite the presence of biosynthetic machinery to synthesize PABA, Plasmodium yoelii, a rodent malaria species, requires exogenous dietary PABA for survival. Mice fed low-PABA diets do not die from lethal doses of P. yoelii. The initiation of a PABA-deficient diet after P. yoelii infection is established leads to the clearance of parasites and subsequent resistance to infection by P. yoelii. An intact immune system is not necessary for protection, given that mice with severe combined immunodeficiency were also protected by PABA-deficient diet. Our studies suggest that the PABA content in the diet will affect the host clearance of malaria parasites and may affect the efficacy of treatments that target the shikimate pathway.

Para-aminobenzoic acid (PABA) used as a marker for completeness of 24 hour urine: effects of age and dosage scheduling

OBJECTIVE

To examine the age dependency of the urinary para-aminobenzoic acid (PABA) excretion, and if a delayed PABA excretion can be overcome by advancing intake schedule; and to examine the recovery of PABA in fractionated urinary samples collected during 24 h after single and repeated doses of PABA.

DESIGN

Cross-over study with subjects randomized to start with recommended schedule of PABA administration (80 mg at 08:00, 12:00 and 18:00; PABA18) and then an advanced schedule (80 mg at 08:00, 12:00 and 15:00; PABA15) or vice versa. One subgroup of eight subjects collected individual urine specimens for 24 h after a morning dose of 80 mg of PABA, and another subgroup of 10 subjects collected individual urine specimens for 24 h after ingestion of 80 mg of PABA three times at mealtimes.

SUBJECTS

Employees and relatives from the Danish Food Administration.

SETTING

Ninety-nine healthy volunteers (61 females and 38 males) aged 30-91 y.

RESULTS

Linear regressions for PABA15 and PABA18 demonstrate significantly less recovery with age (PABA15: r(2)=0.1784, P=0.0002; PABA18: r(2)=0.1273, P=0.0019). Linear regression of DeltaPABA (PABA15-PABA18) with age showed the best fit line to be horizontal (slope -0.0066, P=0.89; 95% CI -0.1046, 0.0915) and with a Y-intercept not significantly different from 0 (1.575; 95% CI -4.176, 7.326). In this population the lower limit for complete 24 h urine collection was 79.2%. After a single dosage of 80 mg PABA 70-85% was recovered after 8 h. Within 16 h after ingestion of 240 mg PABA at recommended hours the lowest acceptable recovery (78.1%) was reached.

CONCLUSION

There is a gradual decline of PABA recovery with age that cannot be overcome by advancing the dosage schedule. Because of a lower delimiting PABA recovery for the elderly, some 24 h collections in this age group will be rejected unjustly (false-negatives). Also, with the currently recommended dosage schedule (PABA taken with the main meals) the risk of false-positive 24 h urine collections prevails. With refinement of the PABA test procedure, ie employing a specific analytical method and age-dependent cut-off values, the test may achieve a higher specificity and sensitivity.

Oral therapy for Peyronie's disease

Peyronie's disease (PD) remains a therapeutic dilemma for the urologist. Despite a myriad of medical therapies proposed for PD there have been limited advances in oral medical treatment. Several new approaches are presented which hold promise of success, although a definitive medical therapy for PD has yet to be established. Since early stage disease is reputed to respond better than well-established plaques, an early trial of inexpensive, safe and well-tolerated oral therapy is often initially recommended. This review discusses the historical aspects as well as contemporary oral medical therapy for PD. With advances in the molecular biology of inflammation and wound healing, the management and understanding of this frustrating disease will no doubt improve.

[Effects of para-aminobenzoic acid on radiosensitivity of mice of different strains]

The aim of the work was to study the possible protective effect of para-aminobenzoic acid (PABA) on the radiation lethality in mice of three inbred lines (BALB/cLacY, C3H/HeY, 101/Hy), stock YT1 and hybrids (C3H/He x 101/H)F1. The PABA solution was given to the mice intraperitoneally in single doses of 10, 50 and 100 mg/kg 40-50 min prior to irradiation with doses of 6 to 8 Gy depending on the line and sex of mice. The used doses of gamma-radiation were roughly LD75/30. The radioprotective effect of PABA was observed in all variants of the experiment but it was relatively low. The protection coefficient varied from 0 to 0.45. The protective effect depended on the line and sex of mice and on the dose of the injected substance.

[Effect of actipol on interferon level in tears (clinico-laboratory study)]

High interferon-inducing activity of a new antiviral drug actipol (0.007% para-aminobenzoic acid) instilled into the eye was demonstrated in animal experiments. In the present study the effect of actipol on interferon production in ocular tissues was investigated clinically. Interferon (IFN) content was measured in washings from the conjunctiva in 20 patients with herpetic keratitis, treated by actipol. Actipol was instilled frequently or injected subconjunctivally parabulbarly. The reference group consisted of 7 patients with herpetic keratitis treated with acyclovir locally. IFN titer was the last dilution of the sample ensuring 50% cell protection in comparison with complete cell destruction in the virus control. The samples were collected before, on days 1, 2, 3, 7 of treatment, and after clinical cure. Time course of IFN concentrations was wave-like in all the patients. The peak of IFN content surpassed the initial level 2-4-fold in all patients (26.13 +/- 5.9 vs. 58.9 +/- 4.4 U/ml, p < 0.01), which seems to be due to actipol induction of IFN production in the surface structures of the eyeball. In the reference group IFN content did not increase in comparison with the control during treatment. Hence, actipol induces the production of IFN in the surface eyeball structures in patients with various forms of herpetic keratitis.

The use of P-aminobenzoic acid and chromic oxide to confirm complete excreta collection in a carnivore, Felis silvestris catus

Complete excreta collection is a pre-requisite for several protocols in protein metabolism, and lack of confidence in achieving this may be increased when working with carnivores. Recovery of p-aminobenzoic acid (PABA) as a check for complete urine collection and chromic oxide for complete faeces collection were assessed in the cat. A single oral dose of PABA (4 mg/kg BW) was excreted more slowly than has been reported in the human (82% recovery at 6 h). A daily dose of PABA proved a useful method for confirming complete urine collection in the cat, and was 99% excreted in 72 h. Chromic oxide (500 mg/cat) was administered orally and recovery of chromium in the faeces was 90% after 96 h. A HPLC method for the analysis of PABA in cat urine was developed, and from the application of the techniques to a nitrogen balance study, it was concluded that PABA and chromic oxide are useful checks for complete excreta collection in the cat.

[Time course of interferon status of patients with herpetic keratitis during treatment with actipol, a new inteferon inducer]

Interferon (IFN) status was evaluated in 20 patients with various forms of herpetic keratitis over the course of treatment with actipol (0.07% para-aminobenzoic acid). Actipol was injected subconjunctivally parabulbarly in combination with instillations into the conjunctival sac or only instilled, depending on the disease severity. The following parameters were evaluated: 1) total content of various IFN types in circulating blood and 2) leukocyte capacity to produce IFN in vitro in patient's whole blood cells. IFN-alpha was induced with Newcastle disease virus and IFN-beta with staphylococcal enterotoxin. Before treatment IFN-producing capacity of blood cells in vitro was decreased in 60% patients and was normal or increased in 40%. Plasma concentrations of IFN were moderately increased in 45% patients. All IFN parameters in patients with initially disordered IFN status normalized during actipol therapy and after clinical cure and did not change in the patients with initially normal IFN values. Hence, local actipol therapy in patients with various forms of ophthalmic herpes modifies IFN status.

Antagonism of 5-hydroxytryptamine(4) receptors attenuates hyperactivity induced by cocaine: putative role for 5-hydroxytryptamine(4) receptors in the nucleus accumbens shell

The localization of 5-hydroxytryptamine(4) (5-HT(4)) receptors suggests their role in the regulation of dopamine (DA) neurotransmission, a speculation that has been supported by neurochemical studies. Mesolimbic DA systems play a prominent role in mediating the behavioral effects of the abused psychostimulant cocaine, and the intent of the present study was to assess the role of 5-HT(4) receptors in the control of spontaneous and cocaine-induced activity. Systemic administration of the 5-HT(4) receptor partial agonist 1-(4-amino-5-chloro-2-methoxyphenyl)-3-[1-butyl-4-piperidinyl]1-propa none hydrochloride (RS 67333; 0.0001-1 mg/kg) or the 5-HT(4) receptor antagonist 4-amino-5-chloro-2-methoxy-benzoic acid-(diethylamino)ethyl ester hydrochloride (SDZ 205,557; 0.0001-1 mg/kg) did not significantly alter spontaneous activity, whereas SDZ 205,557 significantly attenuated cocaine-induced horizontal activity and rearing. To test the hypothesis that cocaine-elicited behaviors were modulated by 5-HT(4) receptors in the nucleus accumbens (NAc) shell, two separate groups of male rats were implanted with bilateral cannulas aimed at the NAc shell. Intra-NAc shell microinjections of either RS 67333 (1 or 3 microgram/0.2 microliter/side) or SDZ 205,557 (1-5 microgram/0.2 microliter/side) did not alter spontaneous activity observed after a systemic saline injection but did significantly attenuate the hyperactivity induced by systemic cocaine injection (10 mg/kg). These results support an involvement of 5-HT(4) receptors, particularly those in the NAc shell, in the locomotor stimulatory effects of cocaine. Furthermore, these data suggest that 5-HT(4) receptors may regulate behavioral processes dependent on mesolimbic DA pathways and may provide a novel target for the development of medications useful in the treatment of both drug dependence and psychiatric disorders.

[Study of interferon-inducing activity of para-aminobenzoic acid injected subconjunctivally in rabbits]

Para-aminobenzoic acid (PABA) is an early interferon inductor. The present study assesses the interferon-inducing activity of PABA (0.007 and 0.06% solutions) and poludan (Poly A:U) injected subconjunctivally to rabbits. Interferon (If) titer in the conjunctival washings and anterior chamber humor was assessed 4-48 h after injection of If inductors. After the first injection of 0.007% PABA, If titer in the conjunctival washings was constantly increasing and reached the maximum after 48 h (64-128 U/ml). Repeated injection of PABA after 5 days still more stimulated the production of If, with the peak after 24 h (128 U/ml); after 48 h the titer of If was still high. If titers induced by 0.007% PABA and poludan were compatible after both injections in the conjunctiva but not in the anterior chamber humor. With poludan, the maximum If titer (16 U/ml) was observed 6 h postinjection, after which it was no longer detected, while after PABA the maximum If titer (64 U/ml) was observed during the 4th and 12th hours postinjection and then decreased, remaining rather high after 24 h. After 0.06% PABA, If titers were 2-4 times lower in all experiments than after 0.007% PABA. The detected interferon-inducing activity of PABA suggests its therapeutic efficacy in ocular diseases involving disorders in If production.

[Comparative assessment of antioxidant activity of para-aminobenzoic acid and emoxipin in retina]

Effect of para-aminobenzoic acid (PABA) on lipid peroxidation (LPO) in rat and guinea pig retina exposed to hypoxic hypoxia is studied. PABA was injected intraperitoneally and parabulbarly before and after hypoxic exposure. Antioxidant activities of PABA and emoxipin were compared. An intraperitoneal injection of PABA in a dose of 10 mg/kg 24 h before hypoxia virtually completely prevented accumulation of lipid peroxides and preserved catalase activity in the retina. Parabulbar injection of 0.01% PABA solution 1 h before hypoxia prevented LPO intensification, stabilized catalase activity in hypoxia, and protected the retina starting from the moment immediately after hypoxic exposure. The efficacy of 0.01% PABA is comparable with that of 1% emoxipin, and a 0.01% solution of emoxipin is less effective than PABA in the same concentration. PABA exerts an antioxidant effect after hypoxia by decreasing the abnormally high level of lipid peroxides and reducing catalase activity in the retina after parabulbar injection of the drug. All the studied concentrations of the drug (from 0.007 to 0.08%) are active, but the optimal dose for the retina is 0.04%. By its efficacy this concentration is equivalent to 1% emoxipin.

Percutaneous absorption of salicylic acid, theophylline, 2, 4-dimethylamine, diethyl hexyl phthalic acid, and p-aminobenzoic acid in the isolated perfused porcine skin flap compared to man in vivo

Human risk assessment for topical exposure requires percutaneous absorption data to link environmental contamination to potential systemic dose. Human absorption data are not readily available, so absorption models are used. In vitro diffusion systems are easy to use but have proved to be somewhat unreliable and are not validated to man. This study compares percutaneous absorption in the isolated perfused porcine skin flap (IPPSF) system with that in man in vivo. The study design utilized the same compounds and the same dose concentration and vehicle in both systems. Methodology for each system was that which is routinely used ineach system. The skin surface was not protected during the absorption dosing period. Percutaneous absorption values were, for man and the IPPSF system, respectively: salicylic acid (6.5 +/- 5.0%; 7.5 +/- 2.6%), theophylline (16.9 +/- 11.3%; 11.8 +/- 3.8%), 2,4-dimethylamine (1.1 +/- 0.3%; 3.8 +/- 0.6%), diethyl hexyl phthalic acid (1.8 +/- 0.5%; 3.9 +/- 2.4%), and p-aminobenzoic acid (11.5 +/- 6.3%; 5.9 +/- 3.7%) (correlation coefficient was 0.78; p < 0.04). The skin surface wash recovery postapplication was similar for salicylic acid in man (53.4 +/- 6.3%) and the IPPSF system (48.2 +/- 4.9%). With the other compounds the majority of surface chemical was recovered in the surface wash and skin tape strip in the IPPSF system. With man, other than salicylic acid, only a few percent applied dose was recovered with surface washing and tape stripping. Since the wash procedure was effective with pig skin, we can assume that these chemicals in man were lost to adsorption to any clothing or bedding with the volunteers. The absorption in man was not less than that in the IPPSF. Assuming the dose was lost in man, it seems plausible that whatever compound was to penetrate human skin in solvent vehicle did so in the period of time before the chemical was removed. The IPPSF system appears to be a good model for predicting percutaneous absorption relative to man. This study design should be used to validate other systems to humans in vivo.

Pharmacokinetic examination of p-aminobenzoic acid passage through the placenta and the small intestine in rats

In the present study the permeability of the rat small intestine and the placenta to p-aminobenzoic acid (PABA) and antipyrine (AP) was investigated. Perfusion of the rat term placenta was used to determine the materno-fetal transfer of both compounds. PABA appeared in the fetal compartment faster than AP (ktransfer = 0.064 and 0.046 min-1, respectively). The rate of equilibration between the maternal and fetal compartments and placental clearance were lower for PABA than for AP (kequilibration = 0.011 and 0.020 min-1; Clp = 0.22 and 0.33 ml/min, respectively); the feto-maternal concentration ratios at equilibrium (FMCReq) were, however, mutually comparable. Similarly, PABA proved to be absorbed from the small intestine significantly faster than AP (ka = 0.824 min-1 and 0.479 min-1; tmax = 3.1 min and 8.9 min, respectively). The apparent volume of distribution (Vd) of AP in non-pregnant animals showed that the drug is distributed into the whole body water as expected (Vd = 0.66 l/kg); however, Vd of AP in pregnant animals was estimated to be 1.81 l/kg. Vd of PABA in non-pregnant animals showed its partially limited distribution, which was only slightly increased in the pregnant animals. Our results confirmed a faster penetration of hydrophilic PABA across the placenta and the small intestine than that of lipophilic AP. The mechanism of transplacental passage of PABA, however, remains to be determined.

Potassium para-aminobenzoate for the treatment of Peyronie's disease: is it effective?

The medical treatment of Peyronie's disease remains controversial. Oral and injectable medications have been used with little documented disease specific effectiveness. Potassium para-aminobenzoate (POTABA) has long been suggested as a treatment for the plaque, curvature, and pain produced by chronic Peyronie's disease. We report a retrospective review of 32 patients treated for at least 3 months with 12 g of POTABA powder daily and followed for 8 to 24 months. Symptom resolution demonstrated improvement in penile discomfort in 8 of 18 patients, decreased plaque size in 18 of 32 patients, and improvement in penile angulation in 18 of 31 patients. Complete resolution of angulation was reported in 8 of 31 patients. While this review was retrospective and uncontrolled, it does suggest a place for POTABA in the treatment of Peyronie's disease. In order to confirm these findings and to control for the natural history of spontaneous resolution of Peyronie's disease symptomatology, a prospective, double-blind, multicenter, well-controlled study with objective criteria should be established.

Para-aminobenzoic acid used as a marker for completeness of 24 hour urine: assessment of control limits for a specific HPLC method

OBJECTIVE AND DESIGN

The study comprised three protocols. Protocol 1 compared a HPLC method with the commonly employed colorimetric diazocoupling method. Protocol 2 examined, if the last dosage of p-aminobenzoic acid (PABA) could be advanced in the old to allow for a delayed age-dependent urinary excretion of PABA. Protocol 3 established limits for recovery of PABA in 24 h urine applying the HPLC method.

SUBJECTS AND SETTING

A total of 151 healthy volunteers participated in the study of which 140 were accepted. In protocol 1: 37 subjects aged 20-78 y were included. All subjects took PABA as recommended (80 mg orally at 08.00, 12.00 and 18.00 h). Protocol 2: compared urinary PABA excretion in two groups of 80 y old subjects who had their last PABA dosage administered at 15.00 h (n = 16) and at 18.00 h (n = 31), respectively. Protocol 3: comprised 56 subjects aged 20-80 y. In the younger age group (20-59 y; n = 34) PABA was taken as recommended, whereas in the older age group (60-80 y; n = 22) the last PABA dosage was advanced three hours.

RESULTS

Protocol 1: HPLC gave significantly lower PABA recovery results compared to colorimetry, the difference between methods being 23.9 +/- 8.5 mg/24 h (P < 0.001). Protocol 2: higher PABA recoveries were demonstrated with the advanced dosage schedule compared to the recommended schedule (208 +/- 14 mg/24 h vs 181 +/- 22 mg/24 h; P < 0.001). Protocol 3: PABA recovery with HPLC was 211 +/- 12 mg/24 h, and the lower limit comprising 95% of subjects was 187 mg/24 h. Similar PABA recoveries were demonstrated in the younger subjects and the older subjects (211 +/- 11 mg/24 h vs 211 +/- 13 mg/24 h; NS).

CONCLUSION

An advanced dosage schedule for PABA in the aged is recommended. Because of lower recoveries with HPLC, the low limit for recovered PABA in a complete 24 h urine differs from the limit based on colorimetry. This study found a limit of 187 mg/24 h corresponding to the lower 95% confidence limit for a single subject.

The ursodeoxycholic acid-p-aminobenzoic acid deconjugation test, a new tool for the diagnosis of bacterial overgrowth syndrome

OBJECTIVE

To determine the possible complementary role of the ursodeoxycholic acid-p-aminobenzoic acid (UDCA-PABA) loading test in the diagnosis of intestinal bacterial overgrowth.

DESIGN

A prospective clinical study.

PATIENTS AND METHODS

The hydrogen breath and UDCA-PABA tests were performed simultaneously in 68 patients with suspected contaminated small bowel syndrome (CSBS), and in 10 healthy control subjects. The hydrogen breath test was performed by oral loading of 25 g of lactose and/or 10 g of lactulose. The UDCA-PABA test was carried out by oral loading of 250 mg of UDCA-PABA conjugate, followed by measurement of the amount of PABA excreted in the urine. The diagnosis of bacterial overgrowth was considered to be established when either the hydrogen breath test or the UDCA-PABA test produced abnormal results.

RESULTS

Thirty-five of the 68 patients proved to have CSBS. In 13 of these 35 patients, only the enhanced urinary PABA excretion (11.7 +/- 1.42 mg vs. 3.6 +/- 0.68 mg) indicated bacterial overgrowth, 15 of the 35 patients gave only a positive hydrogen breath test, and in the remaining seven cases the results of both tests were abnormal. In eight CSBS patients, the urinary excretion of PABA was decreased significantly following 10-day tinidazole treatment (5.5 +/- 1.29 mg vs. 13.1 +/- 2.07 mg).

CONCLUSION

The UDCA-PABA test is a valuable clinical method for the detection of bacterial overgrowth, especially in cases where hydrogen production alone fails to reveal CSBS. It is also a useful procedure for evaluating the efficacy of antibacterial treatment.

Proteinase inhibitors and pemphigus vulgaris. An in vitro and in vivo study

The aim of this study was to determine the inhibitory effect of clinically usable proteinase inhibitors p-aminomethylbenzoic acid (PAMBA), and aprotinin on acantholysis in skin organ culture and in clinical trials with pemphigus patients. PAMBA added to the culture medium at a concentration of 1 mg/ml fully prevented the acantholysis, while Contrykal at 10 ATrE/ml reduced acantholysis. Subsequently, we treated 12 patients (groups 1) with PAMBA 100-200 mg daily for 7 to 26 days in combination with a moderate dose of corticosteroid (mean dose 36.1 mg prednisolone equivalent) or immunosuppressive drugs. A second group of 12 patients (group 2) were treated with a high dose of corticosteroid (mean 94.2 mg prednisolone equivalent) and immunosuppressive drugs. Evaluation was performed before treatment, after 3 weeks and on discharge using a clinical scoring system. The inclusion of PAMBA in the treatment protocol of group 1 resulted in active disease being brought under control with lower corticosteroid doses. As a result, fewer side effects were observed in group 1 than in group 2. In our opinion, protease inhibitors may be useful as adjuvant drugs in the combination therapy of pemphigus.

Photopatch test reactivity: effect of photoallergen concentration and UVA dosaging

We have studied the influence of variations in allergen concentration and UVA dosaging on the results of photopatch testing with the Scandinavian standard photopatch series in 29 patients with photocontact and/or contact allergy to 1 or several of the allergens in that series. Photocontact test reactions were more sensitive to allergen dilution than plain contact test reactions. Even dilution from the standard 5% to 2.5% significantly reduced para-aminobenzoic acid photocontact test reactions. Reducing the UVA dose from the standard 5 J/cm2 to 2.5 or 1 J/cm2 in 2 out of 5 cases turned a significant (++) reaction into a doubtful one (+). Increasing the standard UVA dose of 5 J/ cm2 to 20-40 J/cm2 turned a single + photocontact reaction to trichlorcarbanilide and a single 1 + plain contact reaction to chlorhexidine into ++ reactions. In the majority of cases, however, neither photocontact nor plain contact test reactions were augemented by UVA doses up to 80 J/cm2. We conclude that a UVA dose of 5 J/cm2 is sufficient for eliciting photocontact allergic test reactions, and that a reduction of either the UVA dose level or the standard allergen concentrations of the Scandinavian photopatch test guidelines may cause loss of significant photocontact test reactions in a proportion of the cases.

Characterization of 5-hydroxytryptamine (5-HT) receptor subtypes influencing colonic motility in conscious dogs

We examined the effects of exogenous 5-hydroxytryptamine (5-HT) and selective 5-HT receptor agonists and antagonists on proximal, middle and distal colonic motility in conscious fasted dogs with extraluminal force transducers implanted chronically. 5-HT (0.003-0.1 mg/kg i.v.) dose-dependently enhanced motility along the entire length of the colon. The 5-HT (0.03 mg/kg i.v.)-induced response was inhibited by 0.1-1.0 mg/kg i.v. methysergide, a 5-HT1/2 antagonist, at all recording sites and by 0.1-1.0 mg/kg i.v. ketanserin, a 5-HT2A antagonist, at the middle and distal sites only. At 1 mg/kg i.v., YM060, a 5-HT3 antagonist, reduced the amplitude of the initial transient high-amplitude contractions induced by 5-HT, but did not affect the tonic contraction induced by 5-HT. At doses up to 3 mg/kg i.v., 2-methoxy-4-amino-5-chlorobenzoic acid 2-(diethylamino) ethyl ester (SDZ205-557), a 5-HT4 antagonist, and hexamethonium (up to 10 mg/kg i.v.) did not affect 5-HT-induced responses at any recording site. Renzapride, a 5-HT4 agonist, also stimulated motility along the entire length of the colon at 0.3 mg/kg i.v.. The renzapride-induced response was inhibited by 1 mg/kg i.v. SDZ205-557 or 3 mg/kg i.v. hexamethonium. m-Chlorophenylbiguanide (m-CPBG), a 5-HT3 agonist, (1 mg/kg i.v.) produced a transient high-amplitude contraction at all recording sites and this contraction was eliminated by pretreatment with 0.03 mg/kg i.v. YM060. The contraction produced by m-CPBG declined rapidly, so the increase in the motility index by m-CPBG was not significant at any recording site. Of the antagonists tested, 0.1-1 mg/kg i.v. methysergide produced a delayed and prolonged contractile response at the middle and distal sites. The onset of the response was delayed about 20 min after application and the response was maintained over the subsequent 60-min observation period. The methysergide (1 mg/kg i.v.)-induced response was inhibited by 3 mg/kg i.v. hexamethonium. The other antagonists, ketanserin, YM060 and SDZ205-557, had no contractile effect at any recording site. These results indicate that exogenous 5-HT stimulates motility along the entire length of the fasted canine colon and that 5-HT-induced responses in the proximal colon are mediated mainly by 5-HT1, whereas those in the middle and distal colon are mediated by both 5-HT1 and 5-HT2 receptors. Renzapride and methysergide also stimulate colonic motility via additional mechanisms. The activation of 5-HT4 receptors and the blockade of endogenous 5-HT inhibitory regulation via 5-HT1 receptors may be involved in the action of renzapride and methysergide respectively.

Determination of p-aminobenzoic acid and its metabolites in rabbit plasma by high-performance liquid chromatography with fluorescence detection

A simple, accurate and sensitive high-performance liquid chromatographic method with fluorescence detection was used for measuring plasma concentrations of p-aminobenzoic acid (PABA) and its three metabolites: p-acetaminobenzoic acid (PAABA), p-aminohippuric acid (PAHA) and p-acetaminohippuric acid (PAAHA). A Cosmosil MS-C18 column (250 x 4.6 mm, 5 microns) was used under temperature control at 40 degrees C. The mobile phase was H2O-CH3CN-CH3COOH (100:3:1, pH 4.0) with a flow-rate of 1.5 ml/min. The excitation and emission wavelengths for fluorescence detection were set at 270 and 350 nm, respectively. Plasma samples (200 microliters) were acidified by the addition of 150 microliters of 1 m HClO4 solution containing salicylic acid (SA) as the internal standard. After centrifugation, 30 microliters of the supernatant were injected onto the column. Using this method, PABA and its three metabolites could be determined within 25 min. Within the investigated concentration ranges of PABA (0.1-50 micrograms/ml), PAABA (0.2-50 micrograms/ml), PAHA (0.1-50 micrograms/ml) and PAAHA (0.5-50 micrograms /ml), good linearity (r > 0.99) for the standard curves was obtained. The validation of this method showed coefficient of variance (C.V.) that was well below 15% for all compounds. After intravenous (i.v.) administration of PABA (20 mg/kg) to rabbits (n = 7), PABA followed a one-compartment open model elimination with a half-life of 10.90 +/- 1.03 min. The mean half lives for PAABA, PAHA and PAAHA were 24.61 +/- 6.42, 12.81 +/- 6.04 and 11.27 +/- 2.77 min, respectively.

Linear atrophoderma of Moulin: treatment with Potaba

Linear atrophoderma is a rare disease, first described by Moulin in 1992 in 5 patients, clinically characterized by hyperpigmented, depressed band-like areas along Blaschko's lines. To date, the disease has no effective treatment. We report the seventh case of this condition in a 16-year-old girl and discuss clinical and histopathologic findings, emphasizing the benefit of the potassium aminobenzoate (Potaba) treatment which provided an early stabilization of the skin lesions.

Topical pharyngeal anesthesia improves tolerance of upper gastrointestinal endoscopy: a randomized double-blind study

BACKGROUND AND STUDY AIMS

The usefulness of topical pharyngeal anesthesia is not well established. The aim of the present study was to determine its benefits in relation to patient tolerance and facilitation of the procedure in unsedated patients undergoing upper gastrointestinal endoscopy.

PATIENTS AND METHODS

A randomized double-blind study comparing Topicaina spray - a mixture of benzocaine butyl aminobenzoate (butoforme), amethocaine, and butacaine - and a placebo was carried out on 256 outpatients referred for diagnostic endoscopy. No additional premedication was used. After the examination, both the tolerance to and difficulty of the intubation and examination were evaluated by patients and endoscopists respectively, using visual analogue scales and a questionnaire.

RESULTS

Three patients (1.2%) did not tolerate the endoscopy. One patient was excluded for unexpected therapeutic endoscopy. One hundred twenty-five patients received the active spray and 127 received the placebo. The two groups were similar with respect to patient characteristics. Both intubation and examination, assessed with visual analogue scales, were better tolerated (both p = 0.0001) and more easily performed (p = 0.02 and p = 0.0001 respectively) in the active treatment group. Patients receiving the active spray had a better tolerance for the procedure, according to questionnaire replies.

CONCLUSIONS

Topical pharyngeal anesthesia in unsedated patients undergoing diagnostic upper gastrointestinal endoscopy improves tolerance and makes examination easier.

Effect of para-aminobenzoic acid on the pharmacokinetics and urinary excretion of cis-diamminedichloroplatinum(II) in rats

Para-aminobenzoic acid (PABA) has been previously reported as being an inhibitor of DDP toxicity, and its use did not result in any observable loss in antitumor activity of DDP. The following studies investigated the effect of PABA on the pharmacokinetics and urinary excretion of cis-diamminedichloroplatinum(II) (DDP) in male Sprague-Dawley rats. DDP was injected i.p. at the dose of 7.5 mg/kg in normal saline alone and with a concurrent i.p. injection of PABA (100 mg/kg). The combined treatment with PABA produced a significant increase in the plasma concentrations of total platinum, without affecting the levels of platinum species in the plasma ultrafiltrate. Similar results were also obtained in additional studies in rats receiving the same dose of DDP plus PABA through different routes of administration (i.e. DDP i.v. and PABA i.p.). Both the area under the total platinum plasma concentration-time curve (AUC) up to 60 min and AUC0-120 min were increased by PABA by an average of 113% and 66% respectively. The administration of PABA in rats was followed by a substantial reduction in total urinary excretion of platinum (P < 0.05) and by a significant (P < 0.01) lower concentration of DDP derived platinum in the urine collected during the first 4 h after treatment. The renal clearance of filterable platinum was reduced by PABA by an average of 67.5% from 1.11 to 0.36 ml/min/100 g body wt. Total 24-h urinary excretion of platinum was also decreased, although not significantly, by PABA. Urine volumes from rats treated with DDP+PABA were similar to those from animals receiving DDP alone. HPLC studies indicate that PABA reacts readily with the species generated from DDP in vitro, while the agent is essentially unreactive toward the parent DDP and does not influence its decomposition rate. The overall data of this study suggest that the protective effect exerted by PABA on DDP toxicity may be at least partially due to its ability to interact with aquated DDP as well as to alter the renal excretion of platinum.

[A pharmacokinetic study of para-aminobenzoic acid administered into the rabbit eye by phonophoresis]

The pharmacokinetics of para-aminobenzoic acid (PABA) was studied after introduction of 3H-PABA in the rabbit eye by phonophoresis (1.8 ml 3H-PABA per eye, calculated from 10 muCi in 1 ml 0.9% sodium chloride). The label was found by liquid scintillation in all studied eye tissues, including the retina. Within 1 h the label content in the tissues was higher than within 3 after the isotope introduction. Thus, in addition to subcutaneous injection (Stroeva et al., 1992), another method of PABA introduction in the eye was used in order to further study its activity as a medicinal drug during treatment of degenerative processes in the retina.

Formulation factors affecting release of drug from topical vehicles. II. Effect of solubility on in vitro delivery of a series of n-alkyl p-aminobenzoates

The major influence on the rate of drug transfer out of its vehicle and into the skin is the thermodynamic activity of the drug within its formulation. This study addresses certain thermodynamic dependencies of topical delivery in a model system. Prototypical water-in-oil (W/O) and oil-in-water (O/W) emulsions and their component phases are used as the test vehicles, polydimethylsiloxane is the membrane, and three homologous n-alkyl p-aminobenzenzoate esters are the test permeants. In an emulsion, the interaction of the compound between the water and oil phase can determine the extent of lowering of the thermodynamic activity in the external phase in contact with the membrane. The emulsifiers (surfactants) impact strongly on partitioning and permeation as a result of the extra solubilizing capacity contributed by the surfactant micelles. The lower flux in the aqueous phase of the O/W emulsion is the result of micellar solubilization, and this solubilization increased with increasing ester chain length. Solubilization is also an influence in nonaqueous phases, but permeant hydrophobicity is without specific influence; therefore, transport become less dependent upon the structure of the compound.

Do 5-HT4 receptors mediate the intestinal secretory response to 5-HT in rat in-vivo?

The involvement of the recently characterized 5-HT4 receptor in the actions of 5-hydroxytryptamine (5-HT) on jejunal, ileal and colonic electrogenic ion secretion was investigated in the rat in-vivo. 5-HT and the 5-HT1-, 5-HT2- and 5-HT4-receptor agonist 5-methoxytryptamine (5-MeOT), induced a rise in transintestinal PD in all regions of the gut. However, the 5-HT4-receptor agonists renzapride and cisapride had no effect. Furthermore, the 5-HT4-receptor antagonists SDZ 205-557 (2-diethylaminoethyl-[2-methoxy-4-amino-5-chloro] benzoate), tropisetron and SB 204070 ([1-butyl-4-piperidinylmethyl]-8-amino-7-chloro-1,4- benzodioxan-5-carboxylate hydrochloride) did not affect the secretory response to either 5-HT or 5-MeOT in the jejunum, but did cause a small inhibition in the ileum and colon. It is concluded that 5-HT4 receptors do not make a contribution to the electrically monitored 5-HT intestinal secretory response in the rat jejunum in-vivo, but may play a small role in the ileum and colon.

Antagonism by SB 204070 of 5-HT-evoked contractions in the dog stomach: an in-vivo model of 5-HT4 receptor function

The ability of 5-hydroxytryptamine (5-HT) to evoke contractile activity in the gastric Heidenhain pouch was measured in conscious dogs using a method in which 5-HT4 receptor-antagonist activity can be measured in-vivo. At doses of 5-HT which evoked short-lived measurable responses (5 or 10 micrograms kg-1, i.v.), it was found that this activity was greatly reduced by atropine (100 micrograms kg-1, i.v.), but was unaffected by methysergide, methiothepin, ketanserin (each at 100 micrograms kg-1, i.v.) or granisetron (10 or 100 micrograms kg-1, i.v.). At best SDZ 205-557 2-diethylaminoethyl-[2-methoxy-4-amino-5-chloro] benzoate; 100 micrograms kg-1, i.v.) reduced the action of 5-HT in 4/5 animals and increased it in the other but its effects were variable in magnitude and not consistently maintained. However, the more potent and selective 5-HT4-receptor antagonist SB 204070 (1-butyl-4-piperidinylmethyl 8-amino-7-chloro-1, 4-benzodioxan-5-carboxylate hydrochloride) dose-dependently antagonized the 5-HT-evoked contractions in all dogs tested. This action was reversible, but long-lasting with an effective half-life of 18.0h when administered at 1 microgram kg-1. The estimated ID50 value was 0.55 microgram kg-1.

Virulence studies of Aspergillus nidulans mutants requiring lysine or p-aminobenzoic acid in invasive pulmonary aspergillosis

To identify steps in fungal intermediary metabolism required by Aspergillus spp. during invasive pulmonary aspergillosis, we have developed murine models involving Aspergillus nidulans as the inoculum. The advantages of using A. nidulans over Aspergillus fumigatus or Aspergillus flavus, which are the most common agents of clinical disease, are the well-understood genetics of A. nidulans and a large range of mutants of this species which are affected in a variety of metabolic pathways. Comparison of the virulence of A. nidulans strains carrying mutations which block the biosynthesis of lysine (lysA2) and p-aminobenzoic acid (pabaA1) shows that lysA2 strains have reduced virulence while pabaA1 strains are entirely nonpathogenic. The pathogenicity of pabaA1 strains can be restored by supplementing the drinking water of animals with p-aminobenzoic acid. The results indicate that the availability of lysine in the lung is limited, and p-aminobenzoic acid is probably not available at all. Thus, models of invasive pulmonary aspergillosis involving A. nidulans can be used to identify metabolic pathways that may be essential for the pathogenicity of A. fumigatus, the predominant pathogenic species, suggesting potential new targets for antifungal therapy.

Multicenter evaluation of sunscreen UVA protectiveness with the protection factor test method

BACKGROUND

Currently there is no consensus on a test method to determine the protectiveness of sunscreens in the UVA region alone.

OBJECTIVE

The protection factor in UVA (PFA) test method was evaluated to determine its ability to detect dose-response, specificity for UVA protection only, and repeatability between laboratories, and to detect whether the protection factors depended on the skin response observed (erythema or tanning).

METHODS

Sunscreens containing 0%, 2%, or 5% oxybenzone, or 7% octyl dimethyl para-aminobenzoic acid were tested by the PFA protocol in five laboratories.

RESULTS

The test method demonstrated ability to distinguish differences between the protection in the oxybenzone formulations but not between the placebo (0%) and the 7% octyl dimethyl para-aminobenzoic acid formula. The protection factors were independent of the type of skin response.

CONCLUSION

These data support the utility and validity of the PFA method for determining the UVA protection provided by sunscreen products.

[Systemic therapy of diffuse effluvium and hair structure damage]

A controlled randomized double-blind study was carried out in 72 female patients to compare tolerance and efficacy of two therapeutic agents containing vitamins of the B-group and L-cystine in different compositions versus a placebo in diffuse effluvia and hair structure lesions. Hair swelling as a criterion of hair quality and frontal and parietal anagen rates in trichograms as criteria of hair growth were determined before and after 4 months of therapy. Treatment with active medication 1 was statistically significantly superior to treatment with the placebo according to these criteria. Treatment with active medication 2 was superior to treatment with the placebo but inferior to treatment with active medication 1. The overall evaluation of efficacy by investigator and patient was in good agreement with these results. The additional active ingredients contained in active medication 1 but not contained in active medication 2 contribute to the efficacy of the medication. They cannot be compensated by the higher amounts of L-cystine contained in active medication 2. Given their good tolerance, no adverse effects were observed with the two active medications.

[The interorgan distribution of tritium-labelled para-aminobenzoic acid in the body of rats after its subcutaneous injection]

To study the pharmacokinetics of para-aminobenzoic acid (PABA), rats were subcutaneously injected with 3H-PABA (1 mkg/g body weight) at the stage (P7) when stimulation of outer segments of the photoreceptor cell morphogenesis is possible (Stroeva et al., 1990). The maximum labelling assayed for radioactivity by scintillation counting was observed in the liver 3 h after the injection while, in the blood the labelling was 3 times lower and, in the retina, one order lower than in the liver and blood. The label was detected in all the three types of tissue in 24 and 48 hours, being reduced by an order in comparison with each previous term of measurement. Biological structures binding 3H-PABA were not determined in the present study.

para-amino benzoic acid in the assessment of completeness of 24-hour urine collections from hospital outpatients and the effect of impaired renal function

Eighteen (29%) of 24-h urine collections made by 63 hospital outpatients attending a gastroenterology clinic were incomplete, as judged by 24 h urine recovery of an oral marker, para-amino benzoic acid (PABA), despite more than the usual efforts to obtain complete collections. Incomplete collections contained significantly less sodium, urea and total nitrogen than full collections. Average outputs were 134 mmol and 103 mmol per day for sodium (P less than 0.02); 301 mmol and 223 mmol for urea (P less than 0.001); and 10.1 g and 8.3 g nitrogen (P less than 0.01) in the complete and incomplete collections respectively. In renal outpatients with a plasma creatinine in excess of 125 mumol per litre, urine recoveries of PABA were reduced, but within the expected range in renal patients whose plasma creatinine was normal.