Mutation-selection balance accounting for genetic variation for viability inDrosophila melanogasteras deduced from an inbreeding and artificial selection experiment

We carried out an experiment of inbreeding and upward artificial selection for egg-to-adult viability in a recently captured population of Drosophila melanogaster, as well as computer simulations of the experimental design, in order to obtain information on the nature of genetic variation for this important fitness component. The inbreeding depression was linear with a rate of 0.70 +/- 0.11% of the initial mean per 1% increase in inbreeding coefficient, and the realized heritability was 0.06 +/- 0.07. We compared the empirical observations of inbreeding depression and selection response with computer simulations assuming a balance between the occurrence of partially recessive deleterious mutations and their elimination by selection. Our results suggest that a model assuming mutation-selection balance with realistic mutational parameters can explain the genetic variation for viability in the natural population studied. Several mutational models are incompatible with some observations and can be discarded. Mutational models assuming a low rate of mutations of large average effect and highly recessive gene action, and others assuming a high rate of mutations of small average effect and close to additive gene action, are compatible with all the observations.

Skin test evaluation in nonimmediate allergic reactions to penicillins

BACKGROUND

Nonimmediate reactions (NIR) to aminopenicillins (AP) are frequent. Although patch testing (PT) and intradermal testing (IT) are used for diagnosis, comparative results have never been adequately performed. We compared PT and IT in subjects with NIR to AP.

METHODS

Twenty-one subjects with NIR to AP and positive IT were re-evaluated. Skin tests were performed with amoxicillin (AX) and ampicillin (AM) at different concentrations in petrolatum, 50, 25, and 5% w/w, for PT and in saline, 20, 2, and 0.2 mg/ml for both PT and IT. Skin biopsies from the site of the positive response were studied with haematoxylin-eosin and immunohistochemistry.

RESULTS

In the re-evaluation, one case was IT and PT negative and was excluded; 20 were IT positive and 18 PT positive for both AX and AM. Decreasing concentrations of AP induced a reduction in positivity in both methods when diluted in saline, but not when mixed in petrolatum (PT only). With both PT and IT, immunohistochemical studies showed a perivascular mononuclear infiltrate with CD4 and CD8 memory cells expressing perforin and granzyme B.

CONCLUSIONS

Both tests appear valuable for the diagnosis of NIR to AP. However, IT diagnosed more patients than PT. The vehicle (saline or petrolatum) had no influence on the response, although in the former the concentration was critical. The immunohistochemical analysis showed skin infiltrates compatible with a T-cell drug reaction.

Olerance of a cluster schedule with a house dust mite extract quantified in mass units: multicentre study

The standardisation of allergenic extracts in micrograms of the major allergen has encouraged the search for new treatment schedules, with the purpose of shortening the number of visits and doses required to reach the maintenance dose without eliciting a greater risk of adverse reactions for the patients. With this objective, a prospective multicentre pharmacovigilance study was designed that included 200 patient with allergic rhinoconjunctivitis and/or allergic asthma sensitised to mites (Dermatophagoides pteronyssinu and/or farinae). The dose increment period was carried out using a cluster schedule, where the optimal dose wa reached after 4 visits, administering two doses in each visit. The duration of the study was 5 months and a total o 1902 doses were administered. At the end of the trial, 31 adverse reactions in 23 patients were recorded. Six of these were systemic (0.3% of t administered doses) recorded in 6 patients (3% of the sample). One was an immediate reaction (grade 1) and delayed (4 mild and 1 moderate). Two were asthmatic exacerbations, 2 cutaneous reactions, 1 rhinitis and 1 an unspecific symptom (not IgE-mediated). Two appeared upon administration of the first vial and the remaining 4 after administration of the third cluster. Therefore, the schedule tested presents an adequate tolerance profile, suggesting savings (compared to th conventional schedule of 13 doses per patient) of 1800 visits and 1000 treatment doses in the whole study.

Concomitant use of policosanol and beta-blockers in older patients

Policosanol is a cholesterol-lowering drug with concomitant antiplatelet effects. It is safe and well tolerated, even in populations with high consumption of concomitant drugs. These data suggest that adverse events (AE) due to drug-to-drug interactions (DDI) with policosanol are not relevant. Experimental data indicate that potential DDI between policosanol and drugs metabolized through the cytochrome P450 hepatic system are not expected, but pharmacodynamic DDI cannot be excluded. Several clinical studies have shown that policosanol decreased arterial pressure compared with placebo, and a pharmacological interaction with beta-blockers was experimentally proven. Therefore, clinical DDI between policosanol and beta-blockers can be expected. This study investigated whether policosanol reinforces the antihypertensive effects of beta-blockers and/or whether this combination impairs some safety indicators or induces specific AE in older patients. After 5 weeks on a diet-only baseline period, 205 older hypercholesterolemic patients taking beta-blockers were randomized to policosanol 5 mg/day or placebo for 3 years. After 1 year on therapy, policosanol significantly reduced (p < 0.00001 versus placebo) low-density lipoprotein-cholesterol (LDL-C) (20.9%), total cholesterol (TC) (19.3%) and triglycerides (TG) (25.7%), whereas it increased (p < 0.01 and p < 0.001 versus placebo) high-density lipoprotein-cholesterol (HDL-C) levels (4.1%). Treatment effects did not to wear off during the 3-year follow-up. At study completion, policosanol lowered (p < 0.00001 versus placebo) LDL-C (34.3%), TC (23.2%) and TG (21.2%) and raised (p < 0.00001 versus placebo) HDL-C (12.3%). Thirty-one patients (15.1%) discontinued the study, 22 in the placebo group (20.6%) and nine in the policosanol group (9.2%). Of these, 20 patients (16 in the placebo group and four in the policosanol group) withdrew from the study due to AE. The frequency of serious adverse events (SAE), mostly vascular, in policosanol patients (3/98, 3.1%) was lower than in the placebo group (15/107, 14.0%). No impairment of safety indicators was observed. Nevertheless, reductions in systolic and diastolic blood pressure were observed in policosanol patients compared with those in the placebo group. The frequency of policosanol patients reporting mild or moderate AE (18/98, 18.4%) was also lower than in the placebo group (30/107, 28.0%). In conclusion, policosanol was well tolerated in elderly patients taking beta-block- ers and did not increase AE. Additional reduction of blood pressure and a lower frequency of SAE were observed in policosanol patients compared with those taking placebo. The cholesterol-lowering efficacy of policosanol was that expected. These results provide support that policosanol therapy added to hypercholesterolemic elderly individuals taking beta-blockers could provide additional benefits in lowering blood pressure; SAE were not more frequent in the policosanol group than in the placebo group and there was no increase in AE.

Effects of d-003, a new substance purified from sugar cane wax, on platelet aggregation and plasma levels of arachidonic acid metabolites in healthy volunteers

D-003 is a mixture of very high molecular weight aliphatic acids purified from sugar cane wax showing cholesterol-lowering and antiplatelet effects proven in experimental and clinical studies. Experimental evidence indicates that inhibition of platelet aggregation induced by D-003 is associated with a reduction of thromboxane B2 (TxB2) and an increase of prostacyclin (Pgl2) serum levels. This double-blinded, randomized, placebo-controlled study was undertaken to investigate whether D-003 (20 mg/day) modifies serum levels of TxB2 and Pgl2 and inhibits platelet aggregation in human healthy volunteers. Thirty-one subjects were randomized to placebo or D-003 at 20 mg/day for 14 days. Serum levels of TxB2 and Pgl2 and platelet aggregation to arachidonic acid (AA) (1.75 mM) and collagen (1 microg/ml) were assessed. D-003 (20 mg/day) significantly reduced (p < 0.001) TxB2by 36.4% and increased Pgl2 serum levels by 31% compared with baseline, and these changes were different from placebo. As expected, D-003 significantly inhibited (p < 0.001) platelet aggregation to AA (81.9-65.6%) and to collagen (75.3-62.3%). No subject withdrew from the study. No drug-related disturbances were observed. We conclude that D-003 at 20 mg/day for 14 days significantly inhibited platelet aggregation to AA and collagen and reduced TxB2 and increased Pgl2 serum levels. These results are consistent with those observed in experimental models, indicating that the antiplatelet effect of D-003 is associated with the observed changes on the levels of AA metabolites. Further studies, however, should explore the mechanism involved in this action in greater depth.

[Spontaneous spinal epidural hematomas: review of 8 cases]

INTRODUCTION

Spontaneous spinal epidural hematoma is a rarely occurring condition. The clinical importance of compressive spinal hematoma is due to its acute and progressive course that can lead to permanent and irreversible neurological deficits if not treated early. Clinical presentation is characterized by acute radicular pain followed by cord compression syndrome.

METHODS

We review eight cases of spontaneous spinal epidural hematomas diagnosed in our neurosurgical service in the last 16 years. Attention was focused on gender, age, medical history, level of the hematoma, preoperative neurological condition, operation interval and postoperative results.

RESULTS

The median age of patients was 63.5 years. A total of five patients were female and three male. The most frequently described symptoms before admission were acute vertebral pain followed by cord compression syndrome. In the MRI, six cases were isointense in T1-weighted images and hyperintense in T2-weighted images. In seven patients a laminectomy with clot removal was performed.

CONCLUSIONS

The most important prognostic factors for recovery after spontaneous spinal epidural hematoma are the level of preoperative neurological deficit and the time to surgical operation.

Highly sensitive PCR assay for routine diagnosis of African swine fever virus in clinical samples

This work provides a novel, highly sensitive, hot start PCR method for rapid and specific detection of African swine fever virus (ASFV) that can be used as a routine diagnostic test for ASFV in surveillance, control, and eradication programs. A confirmatory test of the specificity of this method based on restriction endonuclease analysis was also developed.

Pressure and temperature dependence of the excess thermodynamic properties of binary dimethyl carbonate + n-octane mixtures

In this work we report several excess thermodynamic properties for the dimethyl carbonate + n-octane system in an effort to better understand their behavior over wide temperature and pressure ranges. From previous experimental pVTx data for this system, the changes in the excess molar Gibbs energies, in the excess molar entropies, and in the excess molar enthalpies due to pressure have been determined over a wide temperature range and for pressures up to 25 MPa. A correlation of the excess volume as a function of pressure was used for each composition and temperature, together with a new, recently proposed equation for the excess molar volume as a function of temperature, pressure, and composition. Excess molar enthalpies and excess molar Gibbs energies at 298.15 K and for pressures up to 25 MPa were calculated using literature data at atmospheric pressure. Furthermore, the excess isothermal compressibility, the excess isobaric expansivity, and the excess internal pressure were calculated. The expression for the internal pressure of an ideal mixture suggested recently by Marczak has been used.Key words: excess thermodynamic properties, dimethyl carbonate, n-octane, high pressure.

Comparison of the efficacy, safety and tolerability of original policosanol versus other mixtures of higher aliphatic primary alcohols in patients with type II hypercholesterolemia

This randomized, double-blind study was undertaken to compare the efficacy and tolerability of policosanol and Octa-60 in patients with type II hypercholesterolemia. After 4 weeks on a diet, 110 patients were randomized to policosanol or Octa-60 5 mg tablets once a day for 5 weeks. The dose was then doubled to 10 mg/day for the next 5 weeks. Policosanol 5 and 10 mg/day significantly lowered low-density lipoprotein-cholesterol (LDL-C) (p<0.0001 and p<0.00001), the main efficacy variable, by 18.6% and 30.2%, while Octa-60 significantly reduced (p<0.05) LDL-C by 10.0% at study completion only. The frequency of policosanol patients reaching reductions of LDL-C > or = 15% after 5 mg/day (37/55; 67.3%) and 10 mg/day (47/55; 88.7%) was greater (p<0.01 and p<0.01) than in the Octa-60 group, which was 5/55 (9.1%) and 20/55 (36.4%). Likewise, the frequency of patients reaching LDL-C values of <3.4 mmol/l at study completion was greater (p<0.001) in the policosanol group (39/55, 70.9%) than in the Octa-60 group (6/55, 10.9%). Policosanol 5 and 10 mg/day significantly lowered (p<0.00001) total cholesterol (TC) (13.4% and 20.4%), LDL-C/high-density lipoprotein-cholesterol (HDL-C) (22.1% and 37.0%) and TC/HDL-C (17.2% and 28.2%). Octa-60 at 10 mg/day lowered (p<0.05) TC (8.7%), LDL-C/HDL-C (12.6%) and TC/HDL-C (9.4%). HDL-C was increased (p<0.001 and 0.0001) by policosanol 5 and 10 mg/day (5.6% and 12.5%) but was unchanged by Octa-60. In both groups, triglycerides remained unchanged. Both treatments were safe and well tolerated. Octa-60, but not policosanol, significantly increased glucose and alanine aminotransferase, but individual values were within the normal range. Four patients (two from each group) discontinued the trial, but only one (in the Octa-60 group) did so because of an adverse event (AE) (skin rash). Overall, three patients (all from the Octa-60 group) reported AEs. In conclusion, original policosanol at 5 and 10 mg/day, but not Octa 60, was effective in patients with type II hypercholesterolemia. Thus, policosanol reached the efficacy criterion for LDL-C reduction in both steps, while Octa-60 failed to reach this goal. In addition, policosanol was better tolerated than Octa-60.

Henoch-Schönlein purpura associated with clarithromycin. Case report and review of literature

OBJECTIVE

To report a case of Henoch-Schönlein purpura that appears to be related to the intake of clarithromycin for pharyngitis/tonsillitis.

CASE SUMMARY

We describe a case of Henoch-Schönlein associated with clarithromycin therapy in a 48-year-old white man with no history of allergic drug reactions. Four days after starting therapy, he came to our hospital emergency room because of a non-pruritic palpable purpuric rash on the trunk and extremities and arthralgias involving elbows and knees. Administration of clarithromycin was suspended, in a few days, arthralgias and skin lesions quickly resolved. Three weeks later, the patient presented again with abdominal pain, dark-red urine and swelling of the legs. Urinalysis revealed proteinuria of 11 g/24 h and hematuria. A percutaneous renal biopsy showed a diffuse endocapillary proliferative glomerulonephritis with segmental areas of fibrinoid necrosis within glomeruli, on immunofluorescence study granular deposits of IgA and C3 were present in the mesangium and capillary walls. A diagnosis of HSP was made. We suspected that the causative agent might be clarithromycin since this was the only drug added before the cutaneous and renal condition appeared.

CONCLUSIONS

Our case and the previous case suggest that HSP may represent a potential adverse effect of clarithromycin, clinicians should be alerted to this potentially severe side effect of such a widely used drug. In accordance with the data obtained and based on the Naranjo algorithm, the adverse reaction could be considered possible.

UNIFAC calculation of thermodynamic properties of binary 1-chloroalkane + alkane and α,ω-dichloroalkane + alkane mixtures: Comparison with Nitta–Chao and DISQUAC predictions

Data available in the literature for vapor–liquid equilibria, activity coefficients at infinite dilution, and enthalpies of mixing for binary mixtures of 1-chloroalkanes or dichloroalkanes with alkanes are used to determine interaction parameters for three versions of the UNIFAC model – the Tassios et al., Larsen et al., and Gmehling et al. versions. The interaction parameters for chlorine and methyl or methylene groups are calculated using data for the thermodynamic properties of 1-chloroalkane + alkane mixtures. In the case of the Gmehling version, the geometrical parameters for chlorine are also determined. In addition, structure-dependent interaction parameters for α,ω-dichloroalkane + alkane mixtures are presented, taking into account the proximity effect. When the two chlorine atoms of the dichloroalkane are more separated, they become more independent, and the reported values of the interaction parameters approach those of 1-chloroalkane. For all of the properties studied the mean deviation obtained with the new parameter values is lower than that obtained with older values. The results for the thermodynamic properties obtained using the new parameters of the three versions of UNIFAC are compared with those of DISQUAC and Nitta–Chao models. Key words: alkanes, chloroalkanes, DISQUAC, excess thermodynamic properties, proximity effect, UNIFAC.

The contribution of modern imaging to planning separation strategies in conjoined twins

BACKGROUND/AIM

An accurate knowledge of the often complex and unexpected anatomy of conjoined twins is required in order to devise appropriate surgical strategies for separation. The recent progress of imaging techniques prompts an assessment of their contribution to planning separation strategies.

MATERIAL AND METHODS

From 1990, we treated 8 consecutive sets of conjoined twins: 1 acardiac-acephalus, 1 epigastric heteropagus, 2 omphalopagus, 2 omphalothoracopagus, 1 ischiopagus tetrapus and 1 parapagus tripus. The first two sets were separated straightforwardly after birth and were excluded. Ultrasonographic and plain and contrast X-ray studies were used in all the remaining sets, angiography in 5, CT in 4, and MRI in 4. Helical CT and magnetic resonance angiography (MRA) were used in 3 sets.

RESULTS

Two sets of omphalopagus twins and one of omphalothoracopagus twins were separated after birth due to brain damage of one twin, cloacal exstrophy and large arterial shunting, respectively. They were assessed using barium studies (3 sets), IVP (3), angiography (2), CT (2) and MRI (1). Three of six babies survived after separation. In the second set of omphalothoracopagus ecocardiography and MRA revealed that the extent of cardiovascular sharing precluded separation. In the remaining two sets of twins respectively ischiopagus and parapagus, the extent of organ sharing was depicted using three-dimensional helical CT and MRI; the four babies are alive after separation.

CONCLUSIONS

Conventional imaging contributes only modestly to separation planning. In contrast, advanced imaging techniques are amazingly efficient in depicting complex fusions that have to be accurately recognised when planning realistic separation strategies.

Successful desensitization to penicillin after diagnostic reassessment

Clinical situations for which penicillin is indicated as the sole effective treatment are not infrequent, in these circumstances penicillin allergy complicates their medical management. No proven alternatives to penicillin are available for treating neurosyphilis, congenital syphilis, or syphilis in pregnant women, it is not possible choosing an alternative non betalactam antibiotic. The management of the patient who has a history of penicillin allergy include skin testing to determine if penicillin-specific IgE antibodies exist, and desensitization if penicillin is the choice treatment. We report a case of successful desensitization to penicillin in a 30 year-old pregnant woman with latent syphilis and penicillin allergy, where the first penicillin study was not positive, but the repetition of diagnosis test (reassessment) with the same betalactam reagents than in the first study two weeks later the initial evaluation was positive, detecting allergic sensitization not detected at the previous examination.

Lack of nonadditive genetic effects on early fecundity in Drosophila melanogaster

Fecundity is usually considered as a trait closely connected to fitness and is expected to exhibit substantial nonadditive genetic variation and inbreeding depression. However, two independent experiments, using populations of different geographical origin, indicate that early fecundity in Drosophila melanogaster behaves as a typical additive trait of low heritability. The first experiment involved artificial selection in inbred and non-inbred lines, all of them started from a common base population previously maintained in the laboratory for about 35 generations. The realized heritability estimate was 0.151 +/- 0.075 and the inbreeding depression was very small and nonsignificant (0.09 +/- 0.09% of the non-inbred mean per 1% increase in inbreeding coefficient). With inbreeding, the observed decrease in the within-line additive genetic variance and the corresponding increase of the between-line variance were very close to their expected values for pure additive gene action. This result is at odds with previous studies showing inbreeding depression and, therefore, directional dominance for the same trait and species. All experiments, however, used laboratory populations, and it is possible that the original genetic architecture of the trait in nature was subsequently altered by the joint action of random drift and adaptation to captivity. Thus, we carried out a second experiment, involving inbreeding without artificial selection in a population recently collected from the wild. In this case we obtained, again, a maximum-likelihood heritability estimate of 0.210 +/- 0.027 and very little nonsignificant inbreeding depression (0.06 +/- 0.12%). The results suggest that, for fitness-component traits, low levels of additive genetic variance are not necessarily associated with large inbreeding depression or high levels of nonadditive genetic variance.

Non-classical 21-hydroxylase deficiency in children: association of adrenocorticotropic hormone-stimulated 17-hydroxyprogesterone with the risk of compound heterozygosity with severe mutations

AIM

To investigate the association between levels of 17-hydroxyprogesterone (17-OHP) and the risk of being compound heterozygous for severe mutations in children with non-classical 21-hydroxylase deficiency (NC21OHD).

METHODS

In 86 Spanish NC21OHD children (75 families) an analysis of the 21-hydroxylase (21-OH) gene was performed by CYP21B-specific polymerase chain reaction amplification, allele-specific oligonucleotide hybridization and Southern blotting. Familial analysis established how the alleles segregated, and allowed the selection of 21-OH-genotyped normal and carrier children, which proved useful in determining a more precise definition of the cut-off for diagnosis. Receiver operating characteristics (ROC) curve analyses were performed to determine the potential value of 17-OHP in predicting compound heterozygosity for severe mutations.

RESULTS

Thirty-four of the 86 children (39%) were found to carry one severe 21-OH mutation (7.3% deletions or conversions, 2.7% 655G, 2.7% Q318X, 1.3% 1172N, 1.3% R356W, and 3.3% double microconversions or small conversions involving single exons). The predominant mutation was V281L (56.7%). P453S and P30L were less frequent (3.3 and 2%). No patient showed two severe mutations. The degree of enzymic deficiency, as measured by basal or adrenocorticotropic hormone (ACTH)-stimulated 17-OHP levels in fully genotyped patients, but not clinical severity (age and number of symptoms at diagnosis), was found to be significantly greater in children with the severe/mild genotype. ROC curve analyses revealed a strong association between ACTH-17-OHP and genotype (area under the curve 0.908, SE 0.057).

CONCLUSION

ACTH-stimulated 17-OHP may predict the risk of severe mutations in compound heterozygosity in children (maximum predictive value 93% sensitivity and 83% specificity for a cut-off at 151 nmol l(-1)), although a certain overlap in individual values is observed and performance of molecular analysis should never be obviated in the genetic counselling of these patients.