Randomized placebo-controlled clinical trial on efficacy and safety of topical 10% Potassium hydroxide for molluscum contagiosum treatment in children

Introduction: Our objective was to assess efficacy, safety and tolerance of topical potassium hydroxide (KOH) 10% for treating Molluscum contagiosum (MC) in children. Material and methods: Randomized, double-blind, placebo-controlled clinical trial including all children 2-16 years with MC infection attending pediatrician primary healthcare visits. The treatment was KOH 10% gel applied once daily up to clearing (maximum 30 days). Results: KOH 10% showed superior efficacy to placebo (55.3% vs 16.3%, p < .001). Time until clearing was inferior with KOH 10% (p = .001). MC lesions were reduced with KOH 10%, which also showed higher efficacy when the instructions of use of the device were modified. KOH 10% patients presented more adverse events (AE) than placebo patients (72.3% vs 31.8%, p < .001). Most patients (91.5%) completely recovered. There were no differences in frequency of AE before and after the change of instructions, intolerance was more frequently reported by parents with new instructions. Conclusions: KOH 10% was superior to placebo in the main efficacy outcome and most secondary efficacy outcomes. KOH 10% patients had more AE and intolerance symptoms than placebo, although there were no severe AE and most patients recovered. KOH 10% is an effective and safe topical treatment for MC infection in children.

Efficacy and safety of topical application of 15% and 10% potassium hydroxide for the treatment of Molluscum contagiosum

BACKGROUND/OBJECTIVES

Molluscum contagiosum is the most common skin infection in children. One topical treatment used for Molluscum contagiosum is potassium hydroxide. The objective of this study was to compare the efficacy of potassium hydroxide topical treatment at different concentrations with that of placebo in terms of complete clearing of Molluscum contagiosum lesions and to assess the safety and tolerance of potassium hydroxide topical treatment.

METHODS

This was a double-blind randomized clinical trial of three treatments (potassium hydroxide 10%, potassium hydroxide 15%, placebo) applied once daily up to complete clearing of lesions (maximum duration 60 days) in 53 children aged 2-6 years in primary health care pediatric offices in Catalonia, Spain.

RESULTS

In the intention-to-treat analysis, potassium hydroxide 10% (58.8%, P = .03) and potassium hydroxide 15% (64.3%, P = .02) had efficacy superior to that of placebo (18.8%). The number of Molluscum contagiosum lesions was significantly reduced with potassium hydroxide 10% and 15%. The main efficacy outcome was achieved in 58.8% of children in the potassium hydroxide 10% group (P = .03 vs placebo) and in 64.3% of children in the potassium hydroxide 15% group (P = .02 vs placebo). Potassium hydroxide 10% and 15% were not significantly different in efficacy from each other. Potassium hydroxide 10% and placebo were better tolerated than potassium hydroxide 15%. No adverse events were reported during the study period.

CONCLUSIONS

Potassium hydroxide 10% and 15% demonstrated high rates of efficacy in clearing Molluscum contagiosum lesions, with potassium hydroxide 10% being better tolerated.

RAD51 foci as a functional biomarker of homologous recombination repair and PARP inhibitor resistance in germline BRCA-mutated breast cancer

Background

BRCA1 and BRCA2 (BRCA1/2)-deficient tumors display impaired homologous recombination repair (HRR) and enhanced sensitivity to DNA damaging agents or to poly(ADP-ribose) polymerase (PARP) inhibitors (PARPi). Their efficacy in germline BRCA1/2 (gBRCA1/2)-mutated metastatic breast cancers has been recently confirmed in clinical trials. Numerous mechanisms of PARPi resistance have been described, whose clinical relevance in gBRCA-mutated breast cancer is unknown. This highlights the need to identify functional biomarkers to better predict PARPi sensitivity.

Patients and methods

We investigated the in vivo mechanisms of PARPi resistance in gBRCA1 patient-derived tumor xenografts (PDXs) exhibiting differential response to PARPi. Analysis included exome sequencing and immunostaining of DNA damage response proteins to functionally evaluate HRR. Findings were validated in a retrospective sample set from gBRCA1/2-cancer patients treated with PARPi.

Results

RAD51 nuclear foci, a surrogate marker of HRR functionality, were the only common feature in PDX and patient samples with primary or acquired PARPi resistance. Consistently, low RAD51 was associated with objective response to PARPi. Evaluation of the RAD51 biomarker in untreated tumors was feasible due to endogenous DNA damage. In PARPi-resistant gBRCA1 PDXs, genetic analysis found no in-frame secondary mutations, but BRCA1 hypomorphic proteins in 60% of the models, TP53BP1-loss in 20% and RAD51-amplification in one sample, none mutually exclusive. Conversely, one of three PARPi-resistant gBRCA2 tumors displayed BRCA2 restoration by exome sequencing. In PDXs, PARPi resistance could be reverted upon combination of a PARPi with an ataxia-telangiectasia mutated (ATM) inhibitor.

Conclusion

Detection of RAD51 foci in gBRCA tumors correlates with PARPi resistance regardless of the underlying mechanism restoring HRR function. This is a promising biomarker to be used in the clinic to better select patients for PARPi therapy. Our study also supports the clinical development of PARPi combinations such as those with ATM inhibitors.

Germline BRCA testing is moving from cancer risk assessment to a predictive biomarker for targeting cancer therapeutics

PURPOSE

Originally, BRCA testing was used for risk assessment and prevention strategies for breast and ovarian cancer. Nowadays, BRCA status may influence therapeutic decision making at cancer diagnosis. Our objective was to analyze whether the medical advances have changed the burden and pattern of referral, and the pathogenic mutation detection rate.

METHODS

We included 969 probands from our hereditary cancer registry who undertook a full BRCA analysis between 2006 and 2014. Chi-square tests were used to compare categorical variables.

RESULTS

The number of genetic tests have raised from 28 to 170, representing a sixfold increase. In 2006, we tested 1.6 relatives/proband while this proportion was four in 2014. Overall, 20 % harbored a deleterious mutation and 11 % had a variant of unknown significance (VUS). There has been a downward trend in the detection rate of VUS. Testing patients with breast cancer during neoadjuvancy has raised from 4 to 25 % (p = 0.002), while testing them during remission has decreased from 79 to 29 % (p < 0.001). The proportion of patients assessed during the first 6 months after their cancer diagnosis has increased from 3 to 34 % (p = 0.001). Risk reducing mastectomy and salpingoophorectomy have raised from 0 to 24 %, and from 36 to 65 %, respectively.

CONCLUSIONS

BRCA testing has experienced a sixfold increase, the number of relatives being tested has doubled, and the test is being performed at earlier phases of the disease. It is necessary to adequate the health resources to preserve the BRCA genetic counseling quality while incorporating BRCA testing for therapeutic decision making.

[Rapid identification and susceptibility testing of Gram-positive cocci in BacT/ALERT blood cultures by direct inoculation into the Vitek 2 system]

INTRODUCTION

To provide the clinician with early information about blood culture results allows a better prognosis and a reduced mortality rate of the patient with sepsis. In order to contribute to this aim, we performed a study for the identification and susceptibility profiling of positive blood cultures by direct inoculation into the automated Vitek 2 system.

MATERIALS AND METHODS

Blood cultures of 57 patients with monomicrobial bacteriaemia due to gram-positive cocci were evaluated. Addition of saponin to the fluid from blood culture bottles was performed prior to the inoculation of Vitek 2 system cards. The same samples were also examined with the standard method starting from agar plate grown subcultures.

RESULTS

Comparison between the results obtained with the standard method and the direct method revealed that 82% of the samples were correctly identified and that 97% of the isolates showed a concordant antimicrobial susceptibility profile for all drugs tested. Compared to the standard method, the very major error rate of the direct method was just 0.5%, the major error rate was 0.5%, and the minor error rate was 2%.

CONCLUSION

These data suggest that addition of saponin to the fluid from blood culture bottles of the BacT/ALERT(®) 3D before inoculation of the appropriate Vitek 2 cards leads to the rapid and reliable identification and susceptibility profiling of gram-positive cocci in blood samples. Compared to the standard method, the direct method would reduce turnaround time by at least 24 hours.

An evaluation of the polymorphisms Ins16bp and Arg72Pro in p53 as breast cancer risk modifiers in BRCA1 and BRCA2 mutation carriers

The close functional relationship between p53 and the breast cancer susceptibility genes BRCA1 and BRCA2 has promoted the investigation of various polymorphisms in the p53 gene as possible risk modifiers in BRCA1/2 mutation carriers. Specifically, two polymorphisms in p53, c.97-147ins16bp and p.Arg72Pro have been analysed as putative breast cancer susceptibility variants, and it has been recently reported that a p53 haplotype combining the absence of the 16-bp insertion and the presence of proline at codon 72 (No Ins-72Pro) was associated with an earlier age at the onset of the first primary tumour in BRCA2 mutation carriers in the Spanish population. In this study, we have evaluated this association in a series of 2932 BRCA1/2 mutation carriers from the Consortium of Investigators of Modifiers of BRCA1 and BRCA2.

A reversed-phase ion-interaction chromatographic method for in-vitro estimation of the percutaneous absorption of water-soluble UV filters

An analytical method based on ion-interaction chromatography with UV detection for simultaneous in-vitro estimation of the percutaneous absorption of the most used water-soluble UV filters in sunscreen cosmetics is proposed. These UV filters were phenylbenzimidazole sulfonic acid, disodium phenyl dibenzimidazole tetrasulfonate, benzophenone-4, and terephthalylidene dicamphor sulfonic acid. The methodology is based on applying the sunscreen containing the target UV filters to human epidermis in a diffusion cell. Analytes are determined in the receptor solution. To ensure skin integrity, screening of the cells was carried out by analytical determination of a marker. Analytical variables such as percentage ethanol, concentration of ion-pairing agent, pH of the mobile phase, and temperature were studied in order to achieve high resolution of the chromatographic peaks in the lowest possible time of analysis. The conditions selected consisted of a mobile phase composed of 35:65 (v/v) ethanol-ammonium acetate buffer solution (pH 4, containing 50 mmol L(-1) tetra-n-butylammonium bromide). The chromatographic determination was carried out with the analytical column at 50 degrees C. UV detection was carried out at the maximum absorption wavelength for each analyte. The limit of detection (3s(y/x)/b) ranged from 16 to 65 ng mL(-1), depending on the analyte.

A haplotype containing the p53 polymorphisms Ins16bp and Arg72Pro modifies cancer risk in BRCA2 mutation carriers

Germline mutations in the BRCA1 and BRCA2 genes confer a high lifetime risk of developing breast and other cancers; however, remarkable differences exist regarding disease manifestation in mutation carriers. It has been suggested that other genetic and/or environmental factors modify not only the appearance but also the age of onset and type of tumor in BRCA1/2-associated cases. The aim of the present study was to investigate the role of two p53 polymorphisms (c.97-147ins16bp and c.215c>g, p.Arg72Pro) as potential modifiers. For this purpose we investigated the possible association between the two polymorphisms and disease status in 447 BRCA1/2 mutation carriers belonging to 170 Spanish breast and/or ovarian cancer families. Genotype and haplotype analyses revealed that the presence of a specific haplotype carrying the allele without the 16-bp insertion and the variant allele for the Arg72Pro (No Ins-72Pro haplotype) was associated with an earlier age of onset in BRCA2 mutation carriers. We found an increased risk of developing a first primary tumor (breast or ovarian) before 35 years of age for individuals who carried at least one No Ins-72Pro haplotype (OR: 2.69; 95% CI: 1.15-6.29; P=0.022). We confirmed these data by a functional study in which we compared different p53 genotypes in relation to their apoptotic response after cell treatment with a cytotoxic drug (AraC). Our results revealed a decrease in p53 apoptotic rate associated with the No Ins-72Pro haplotype.

A liquid chromatography–fluorimetric method for the in vitro estimation of the skin penetration of disodium phenyldibenzimidazole tetrasulfonate from sunscreen formulations through human skin

Disodium phenyldibenzimidazole tetrasulfonate (PDT) is a new organic UV filter with hydrophilic properties used in modern sunscreen spray formulations. The aim of this work was to develop and validate an analytical method that can be used to study skin absorption of PDT from sunscreens. Results obtained in vitro for human skin showed a low level of absorption. The proposed in vitro method employs a diffusion cell. Sunscreen lotion was applied onto pretreated human skin, which was then placed in the cell. PDT was collected in a receptor liquid, the surface of which was in contact with the skin. The solutions obtained were diluted appropriately and analyzed by liquid chromatography without any interference. The analytical features of chromatographic determination with fluorimetic detection were suited to this analytical problem, since this method gave a limit of detection of 1 ng ml(-1). Phenol red (PR) was used as a marker to check the skin integrity, and a sensitive method based on sequential injection on-line solid-phase extraction coupled with spectrophotometric detection was developed for determining this marker in the receptor liquid in order to screen the cells.

[Cholesterol, alpha-tocopherol, and retinoid concentrations in silicone oil used as a vitreous substitute]

OBJECTIVE

To verify the existence of organic lipophylic compounds in silicone oil extracted from human eyes following its use for previous retinal detachment, and to determine the intraocular permanence time of these substances in the oil.

METHODS

Concentrations of retinoic acid, retinol, retinal, cholesterol and alpha-tocopherol were detected by HPLC in 23 samples of silicone oil extracted from patients with complicated retinal detachments. The time interval between the time of injection of the silicone oil and the subsequent assessment varied from 3 to 50 months (the permanence time).

RESULTS

All tested compounds were found in the samples, but these were most commonly cholesterol and less frequently alpha-tocopherol. There was an inverse relationship between retinoic acid concentration and age (p=0.023), and a direct relationship between cholesterol concentration and permanence time (p=0.0008) at least up to 20 months.

CONCLUSIONS

These findings confirm that silicone oil is not an inert substance but is capable of extracting lipophylic compounds from the intraocular tissues. There is a clear linear elevation of cholesterol levels with increased intraocular permanence time. This finding could be used to further establish a safe permanence time for intraocular silicone oil used in ophthalmologic surgery. More studies with larger samples are warranted to evaluate this further.

Clinical and pathological findings of BRCA1/2 associated breast cancer

It is not known if the behaviour of hereditary breast cancer (HBC) differs from that of sporadic breast cancer (BC). The aim of the present study was to analyze clinical-pathological characteristics in patients with BRCA1/2-mutation associated to BC. These data could be useful in the management of HBC. This study includes 17 patients with BC in whom a germ-line BRCA1/2-mutation was diagnosed. The patients were from 10 different families, and four patients had no family history of BC or ovarian cancer (OC). The study of mutations was with the protein truncation test (exon 11 for BRCA1, exons 10 and 11 for BRCA2) and sequencing (the rest of exons). At diagnosis the mean age was 37 years (28-54). Only 3/17 patients presented with involvement of axillary nodes; no patient was diagnosed with metastatic disease. All cases were infiltrating ductal carcinoma; two of them were medullary carcinoma. Histological grade was available in 13/17 cases, with grade III being the most frequent (12/13). Hormonal receptors were negative in 8/10 patients. The mean follow-up was 129 months (23-223). There were three local recurrences at 17, 108 and 151 months; and two distant relapses at 15 months (complete remission) and 92 months. There were three diagnosed contralateral BC. Hereditary breast cancer has malignant pathological features, but the clinical behaviour may be less aggressive than sporadic breast cancer in the same age group.

Pre-test prediction models of BRCA1 or BRCA2 mutation in breast/ovarian families attending familial cancer clinics

OBJECTIVE

To test whether statistical models developed to calculate pre-test probability of being a BRCA1/2 carrier can differentiate better between the breast/ovarian families to be referred to the DNA test laboratory.

STUDY DESIGN

A retrospective analysis was performed in 109 Spanish breast/ovarian families previously screened for germline mutations in both the BRCA1 and BRCA2 genes. Four easy to use logistic regression models originally developed in Spanish (HCSC model), Dutch (LUMC model), Finnish (HUCH model), and North American (U Penn model) families and one model based on empirical data of Frank 2002 were tested. A risk counsellor was asked to assign a subjective pre-test probability for each family. Sensitivity, specificity, negative and positive predictive values, and areas under receiver operator characteristics (ROC) curves were calculated in each case. Correlation between predicted probability and mutation prevalence was tested. All statistical tests were two sided.

RESULTS

Overall, the models performed well, improving the performances of a genetic counsellor. The median ROC curve area was 0.80 (range 0.77-0.82). At 100% sensitivity, the median specificity was 30% (range 25-33%). At 92% sensitivity, the median specificity was 42% (range 33.3-54.2%) and the median negative predictive value was 93% (range 89.7-98%). BRCA1 families tended to score higher risk than BRCA2 families in all models tested.

CONCLUSIONS

All models increased the discrimination power of an experienced risk counsellor, suggesting that their use is valuable in the context of clinical counselling and genetic testing to optimise selection of patients for screening and allowing for more focused management. Models developed in different ethnic populations performed similarly well in a Spanish series of families, suggesting that models targeted to specific populations may not be necessary in all cases. Carrier probability as predicted by the models is consistent with actual prevalence, although in general models tend to underestimate it. Our study suggests that these models may perform differently in populations with a high prevalence of BRCA2 mutations.

[Clinical and pathological characteristics and clinical course of patients with breast cancer and BRCA1/BRCA2 mutations]

BACKGROUND

Clinico-pathological differences between BRCA1 or BRCA2 mutation-associated breast cancer (BC) and sporadic BC are little known.

PATIENT AND METHODS

We analysed the clinico-pathological characteristics and clinical follow-up of 30 patients with BC. BRCA1 and BRCA2 mutations were detected by SSCP and PTT.

RESULTS

There were no differences in age, size or nodal status at the time of diagnosis. Mammography features were more heterogeneous in BRCA2 than in BRCA1 BC. All BRCA1 mutation-associated BC corresponded to infiltrating ductal carcinomas (20% medullary carcinomas) with a more aggressive pathological behavior. The frequency of local recurrences was 14% in BRCA1 and 20% in BRCA2. Contralateral BC and ovarian cancer (OC) were observed in 27% and 20% of BRCA1 cases, respectively, and 6% and 6% of BRCA2 cases. The median follow-up in BRCA1 and BRCA2 BC was 131 and 54 months, respectively.

CONCLUSIONS

There were no differences in age at diagnosis and stage between BRCA1 and BRCA2 breast cancer. The mammographic pattern in BRCA2 was more heterogeneous. BRCA1 mutations were associated with more aggressive histopathologic findings and a higher risk of a second BC and OC.

Conditions for single-strand conformation polymorphism (SSCP) analysis of BRCA1 gene using an automated electrophoresis unit

The single-strand conformation polymorphism procedure has been applied in routine testing for hereditary diseases and cancer. However, temperature, running time, gel composition, fragment length, etc. can influence its sensitivity. Mutation detection in the clinical setting depends on the development of automated technology, especially for large genes such as the breast cancer gene BRCA1. We analysed DNA samples with BRCA1 mutations in an automated system (GenePhor System; Amersham-Pharmacia Biotech, Uppsala, Sweden). The concentrations of DNA template and PCR primers, the effect of chilling after denaturation, and the temperature and time of the electrophoresis were investigated. All band-shifts were detected by electrophoresis at 5 degrees C for 2 h 15 min. Concentrations of DNA and samples used in the PCR did not affect the SSCP pattern, but chilling the PCR product in ice after denaturation was required. The type and position of mutation in the fragments did not influence the probability of a mobility shift, although SSCP analysis was more sensitive for fragments shorter than 350 bp. This automated SSCP method meets the requirements of fast turnaround and sensitivity and can be readily adapted to the screening of large genes such as BRCA1.

BRCA2 germ-line mutations in Spanish male breast cancer patients

BACKGROUND

Mutations in the BRCA2 gene account for the majority of the families with male and female breast cancer cases, and a number of BRCA2 mutations have been reported in males with breast cancer. The aim of this study was to characterise BRCA2 germ-line mutations in Spanish male breast cancer patients.

PATIENTS AND METHODS

We screened DNA from 11 affected men and 6 women with breast cancer (BC) who had an affected male relative (father or brother). Exons 2-9 and 12-27 were screened by SSCP, and exons 10 and 11 were screened by PTT. PCR products with a variant band were sequenced.

RESULTS

Three BRCA2 frameshift mutations were identified (17.6%): the 3374delA in codon 1049 (exon 11), 6857delAA in codon 2010 (exon 11), and 9254delATCAT in codon 3009 (exon 23). These mutations were present in patients with affected first-degree relatives (3 of 9, 33%). The proportion of male patients with a family history of BC in at least one first-degree relative was 53%.

CONCLUSIONS

There is an association between BRCA2 mutations and male breast cancer, especially in those with a family history of BC. The high prevalence of BRCA2 mutations among males should be considered when estimating risk for female relatives. All new male cases of BC should be regarded as being possibly inherited and should be fully investigated.

BRCA1 mutation analysis in 83 Spanish breast and breast/ovarian cancer families

A group of 83 Spanish BC/OC families were analysed for BRCA1 germ-line mutations. Analysis of the entire coding sequence was carried out by SSCP and PTT. We identified 5 frameshift mutations: 185delAG (2 times), 189insTGTC, 1241delAC, and 5537delA and 3 missense mutations in BRCA1: 330A > G, 1240C > T, and 5263G > A. The 185delAG mutation was identified in 2 families. One of them was the only Gypsy family participating in our study. All carriers shared the known founder haplotype, although they did not have any Jewish ancestry. Three frameshift mutations were found among the 14 families with 3 or more BC cases and 1 or more OC, which results in a higher percentage (21.4%) of BRCA1 mutations in this group of high risk families. Two missense mutations were found in families with 2 or 3 BC and no OC, indicating a low proportion (4.8%) of mutations in these families. There was no association between bilateral BC and a mutation carrier status. The frequency of BRCA1 involvement is lower than that of any other country hitherto reviewed. Our results highlight the influence of geographical and ethnic origin of the population studied.

Two contiguously located germline BRCA1 mutations in a Spanish early-onset breast cancer family

We identified two BRCA1 mutations in a high risk breast cancer family: the missense 1240 C > T (Thr > Ile) and the 1241delAC at codon 374, which results in a stop at codon 376. Both were contiguously located in the same BRCA1 gene, in a motif of 11 amino acids, which is highly conserved across human, canine and murine species. The presence of missense mutations in this motif in breast-cancer families suggests an important functional role for this protein region and a potential deleterious effect of the 1240C > T mutation.

Prevalence of BRCA1 and BRCA2 Jewish mutations in Spanish breast cancer patients

We screened the 185delAG and 5382insC (BRCA1) and the 6174delT (BRCA2) mutation in 298 Spanish women with breast cancer. Two women (one with Sephardic ancestors) presented the 185delAG mutation and the same haplotype reported in Ashkenazim with this mutation. This suggests a common origin of the 185delAG in both Sephardic and Ashkenazi populations.

[The identification of a new mutation in the BRCA2 gene by protein truncation analysis in a Spanish family with hereditary breast cancer]

The BRCA2 mutations are implicated in a high percentage of hereditary breast cancer cases. We report a novel mutation in a Spanish breast cancer family. We analyzed DNA samples of the proband and of the living first and second degree relatives. Exon 11 of BRCA2 gene were screened by the protein truncation test and direct sequencing. We identified a novel mutation, 6857 delAA, in three affected women, diagnosed of breast cancer at 29, 51 and 45 years of age, respectively, and in a healthy male. The BRCA2 mutation seems to be implicated in the development of early-onset breast cancer cases in this family. Identification of this novel mutation adds to the information on BRCA2 gene in hereditary breast cancer in Spanish population.

Identification of the 185delAG BRCA1 mutation in a Spanish Gypsy population

The 185delAG BRCA1 deletion occurs with a high frequency in Ashkenazi Jews. We detected this mutation in two Spanish Gypsy women (the only Gypsy participants) in an extensive study of 90 high-risk families and 160 women with early-onset breast cancer. One of these Gypsy women belonged to a high-risk family and the other had had early-onset breast cancer. The mutation was also detected in 1 out of 25 Gypsy samples unrelated to breast cancer. All the samples with the mutation shared the marker alleles present in Jewish samples with 185delAG. This is the first report of this mutation in a non-Jewish well-defined ethnic population. According to these findings the carrier frequency of this mutation in Gypsy individuals could be several times higher than that of the general population, and this should be taken into consideration in genetic screening for cancer in Gypsy populations.

Molecular analysis of the six most recurrent mutations in the BRCA1 gene in 87 Spanish breast/ovarian cancer families

BRCA1 accounts for nearly all families with multiple cases of both early onset breast and ovarian cancer and about 45% of families with breast cancer only. Although to date more than 200 distinct mutations have been described, several have been found to be recurrent in the gene. We have analyzed 87 Spanish breast/ovarian cancer families for the six most recurrent mutations in the BRCA1 gene. The analysis of the five exons where these mutations are located was made using the SSCP and sequenciation techniques. Four mutations were found in our families and only two carried one of the six mutations analyzed. In both cases the mutation identified was 185delAG. Our results suggest that these six mutations are not specially recurrent in the Spanish population and that differences in the geographical origin of the families can influence the type and proportion of mutations identified.

The influence of polymer concentration on the 5-fluorouracil release rate from carbopol hydrogels

5-Fluorouracil (5-FU) release kinetics from Carbopol 940 hydrogels prepared at pH 5.5 and five different polymer concentrations (0.0010, 0.0015, 0.0020, 0.0025 and 0.0030 w/w) were determined using Franz diffusion cells. Higuchi's equation for release from solutions was used to calculate the diffusion coefficients of 5-FU in the hydrogels. An empirical equation was obtained for the estimation of diffusivity of 5-FU as a function of polymer concentration, which from a practical view point can be considered useful in preformulation studies. Furthermore, the values of viscosity for all hydrogels assayed were determined. The diffusivity-viscosity relationship resembles the Stokes-Einstein equation for small solutes in liquid phases and provides a factor indicative of additional resistance offered by the gelling agent for drug diffusion.