Usefulness of liquid-crystal oral formulations to enhance the bioavailability and skin tissue targeting of p-amino benzoic acid as a model compound.

Topical formulations are not always suitable to deliver active ingredients to large areas of skin. Thus, in this study, we aimed to develop an oral formulation for skin tissue targeting with a high bioavailability using liquid crystal (LC) dispersions comprising cubosomes of a mal-absorptive model compound, p-amino benzoic acid (PABA), which is an active element in cosmeceuticals, dietary supplements and skin disorder medicines. The bioavailability and skin concentration of PABA were investigated after oral administration in rats. The effect of the remaining amount of the LC formulation in the stomach on the pharmacokinetic profiles of orally administered PABA was evaluated. The skin permeation and concentration of PABA were also investigated using an in vitro permeation experiment. As a result, the bioavailability of PABA was significantly improved by administration of PABA-LC formulations compared with PABA solution alone, although the effect was greatly influenced by the type of LC-forming lipids. The in vitro skin permeation study showed that the PABA concentration in the skin when applied from the dermis side was higher than when applied from the epidermis side. These findings suggested that oral administration advantageously supports skin targeting, and oral LC formulations could be a promising material in cosmeceutical, dietary and clinical fields.

Growth-inhibitory and chemosensitizing effects of the glutathione-S-transferase-π-activated nitric oxide donor PABA/NO in malignant gliomas.

Glutathione-S-transferases (GSTs) are upregulated in malignant gliomas and contribute to their chemoresistance. The nitric oxide (NO) donor PABA/NO (O(2) -{2,4-dinitro-5-[4-(N-methylamino)benzoyloxy]phenyl} 1-(N,N-dimethylamino)diazen-1-ium-1,2-diolate) generates NO upon selective enzymatic activation by GST-π-inducing selective biological effects in tumors. Tumor cell killing and chemosensitization were observed in a variety of tumors after exposure to GST-activated NO donor drugs. In our project, cytotoxic and chemosensitizing effects of PABA/NO in combination with carboplatin (CPT) and temozolomide (TMZ) were studied in human U87 glioma cells in vitro and in vivo. U87 glioma cells were exposed to PABA/NO alone or in combination with CPT or TMZ for 24 hr. Cell viability was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay after 24-hr incubation and 48 hr after drug removal. The antiproliferative effect of PABA/NO was assessed in an intracranial U87 glioma nude rat model comparing subcutaneous administration and intratumoral delivery by convection-enhanced delivery. PABA/NO monotherapy showed a strong dose-dependent growth-inhibitory effect in U87 glioma cells in vitro, and a strong synergistic effect was observed after concomitant treatment with TMZ, but not with CPT. Systemic and intratumoral PABA/NO administration significantly reduced cell proliferation, but this did not result in prolonged survival in nude rats with intracranial U87 gliomas. PABA/NO has potent antiproliferative effects, sensitizes U87 glioma cells to TMZ in vitro and shows some in vivo efficacy. Further studies are still required to consolidate the role of NO donor therapy in glioma treatment.

The effect of intravesical instillation of antifibrinolytic agents on bacillus Calmette-Guerin treatment of superficial bladder cancer: a pilot study.

PURPOSE: We determined whether intravesical instillation of antifibrinolytic agents could improve the antitumor effect of bacillus Calmette-Guerin. We also investigated the impact of these antifibrinolytic agents on the dose of bacillus Calmette-Guerin required for a therapeutic effect. MATERIALS AND METHODS: In this randomized, prospective, double-blind, controlled pilot study 257 patients with superficial bladder cancer were randomized into groups A through E. They received 100 to 120 mg intravesical bacillus Calmette-Guerin plus 100 mg para-aminomethylbenzoic acid, 50 to 60 mg bacillus Calmette-Guerin plus 100 mg para-aminomethylbenzoic acid, 100 to 120 mg bacillus Calmette-Guerin plus 2.0 gm epsilon aminocaproic acid, 50 to 60 mg bacillus Calmette-Guerin plus 2.0 gm epsilon aminocaproic acid and 100 to 120 mg bacillus Calmette-Guerin alone, respectively. Prothrombin time and activated partial thromboplastin time of each patient were determined at 2 hours after instillation, and adverse events were evaluated. Tumor recurrence was assessed every 3 months postoperatively by cystoscopy. Median followup was 26.0, 25.0, 24.5, 25.0 and 25.5 months, respectively. RESULTS: No significant change in prothrombin time or activated partial thromboplastin time was observed, and analysis showed no significant difference in prothrombin time or activated partial thromboplastin time among groups A through E (p = 0.693, 0.756). Recurrence rates at a minimum of median 2 years were 10.6%, 11.1%, 10.0%, 9.3% and 31.8% in groups A through E, respectively. The log rank test showed that recurrence-free probability was statistically different comparing groups A, B, C and D with group E, respectively (p = 0.023, 0.037, 0.031 and 0.020), while pairwise comparisons among groups A, B, C and D showed no significant differences (each p >0.05). The rate of serious adverse events in groups A through E was 9.6%, 3.9%, 15.7%, 5.9% and 13.5%, respectively. However, the differences were not significant (p = 0.222). CONCLUSIONS: Intravesical instillation of para-aminomethylbenzoic acid or epsilon aminocaproic acid is a more effective and safer method to improve the bacillus Calmette-Guerin antitumor effect, and can reduce the dose of bacillus Calmette-Guerin with the same effect as the full dose.

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.

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.

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.

Dietary modulation of malaria infection in rats.

Feeding of wistar albino rats on low protein and energy diet (4% protein) caused suppression of parasitaemia when infected with Plasmodium berghei besides causing a depressed immune response. The refeeding of protein energy deficient rats on normal protein and energy diet (18% protein) for four weeks resulted in the normal course of parasitaemia after P. berghei infection. The present study was carried out to find the cause of suppression of malaria in protein energy deficient rats. The experiments revealed re-elevation of malaria parasitaemia when rats were fed on low protein diets supplemented with p-amino-benzoic acid (PABA). Moreover, the parasite persisted at subpatent levels in tissues in protein energy deficient rats and resulted in the development of antimalarial antibodies. Low protein energy diet could cause deficiency of certain essential nutrients required for the parasite, PABA being one of them, and hence suppresses the parasitaemia to subpatent levels. As a result, sufficient antigenic stimulus is provided to the host so that the host develops an immune response which might in turn help in further suppression of parasitaemia to subpatent levels.

The bentiromide test using plasma p-aminobenzoic acid for diagnosing pancreatic insufficiency in young children. The effect of two different doses and a liquid meal.

The bentiromide test was evaluated using plasma p-aminobenzoic acid as an indirect test of pancreatic insufficiency in young children between 2 months and 4 years of age. To determine the optimal test method, the following were examined: (a) the best dose of bentiromide (15 mg/kg or 30 mg/kg); (b) the optimal sampling time for plasma p-aminobenzoic acid; and (c) the effect of coadministration of a liquid meal. Sixty-nine children 91.6 +/- 1.0 years) were studied, including 34 controls with normal fat absorption and 35 patients (34 with cystic fibrosis) with fat maldigestion due to pancreatic insufficiency. Control and pancreatic insufficient subjects were studied in three age-matched groups: (a) low-dose bentiromide (15 mg/kg) with clear fluids; (b) high-dose bentiromide (30 mg/kg) with clear fluids; and (c) high-dose bentiromide with a liquid meal. Plasma p-aminobenzoic acid was determined at 0, 30, 60, and 90 minutes then hourly for 6 hours. The dose effect of bentiromide with clear liquids was evaluated. High-dose bentiromide best discriminated control and pancreatic insufficient subjects, due to a higher peak plasma p-aminobenzoic acid level in controls, but poor sensitivity and specificity remained. High-dose bentiromide with a liquid meal produced a delayed increase in plasma p-aminobenzoic acid in the control subjects probably caused by retarded gastric emptying. However, in the pancreatic insufficient subjects, use of a liquid meal resulted in significantly lower plasma p-aminobenzoic acid levels at all time points; plasma p-aminobenzoic acid at 2 and 3 hours completely discriminated between control and pancreatic insufficient patients. Evaluation of the data by area under the time-concentration curve failed to improve test results. In conclusion, the bentiromide test is a simple, clinically useful means of detecting pancreatic insufficiency in young children, but a higher dose administered with a liquid meal is recommended.

Host diet in experimental rodent malaria: a variable which can compromise experimental design and interpretation.

Over the past few years several experienced groups studying malaria have encountered significant problems with their particular rodent malaria-host system. This has involved, in some cases, periods during which the recovery of cryopreserved parasite stocks and growth of bloodstream parasites was markedly inhibited and, in other cases, periods of drastically increased mortality rates. The common factor linking these incidents was that they coincided with alterations in the experimental animal diet used. The inhibition of growth of cryopreserved stabilates or bloodstream parasites was abolished by supplementation with p-aminobenzoic acid (PABA) or by changing the diet used. Although the suppressive effects of diets lacking PABA on parasite growth have been known for over 30 years, the variation of PABA levels in modern laboratory animal feed concentrates is not well recognized. We have not established the exact cause of increased mortality, but it has been overcome by changing the diet used. We are documenting our experiences with this potential variable to forewarn workers in other laboratories of possible problems inherent in the use of different diets.

Topical protection against long-wave ultraviolet A.

A PABA ester-oxybenzone preparation is superior to PABA or sulisobenzone alone in protecting the skin from methoxsalen-induced ultraviolet A (UVA) phototoxicity after water substantivity challenge. Such a mixture would be useful as a UVA screen for uninvolved or actinically damaged skin in patients receiving psoralens and ultraviolet A (PUVA) therapy. An effective topical UVA screen also may protect against UVA-induced diseases like solar urticaria, polymorphic light eruptions, drug-induced phototoxicity or photoallergy, and possibly against the deep degenerative changes of solar elastosis.

[Clinical trial of K-247].

The clinical trial of K-247, an anticancer drug showing antitumor effect by new mechanism of action, was performed in a total of 22 patients with a variety of advanced cancers, consisting of 10 cases administered singly and 12 cases combined with other anticancer agents. All patients were treated three or four times every day with oral administration of K-247 (600-800 mg/day). Including one patient receiving a high dosage (over 200 g totally) of K-247, in all cases, no appreciable side effect causing suspension of the administration was recognized. In combination therapies with other anticancer drugs there was rather found a tendency to rescue WBC from decrease. As a clinical result, although all cases tested were insusceptible to prior chemotherapy with various anticancer drugs, one case, which has received palliative operation for rectal cancer accompanied with pelvic infiltration, was experienced after administration of K-247 only, in which the destructive lesion of left sacral on X-ray photograph was restored to almost normal condition and the patient's complaints such as severe pain in the lower legs and difficulty in walking were completely disappeared.