Clinical Practice Guidelines for Diagnosis and Management of Hypersensitivity Reactions to Quinolones

The consumption of quinolones as first-line treatment has increased in recent years, leading to an increase in the incidence of hypersensitivity reactions (HSRs) to this antibiotic group. Both diagnosis and management of HSRs to quinolones are complex and controversial. These practical guidelines aim to provide recommendations for effective clinical practice. The recommendations were drafted by an expert panel that reviewed the literature regarding HSRs to quinolones and analyzed controversies in this area. Most HSRs to quinolones are immediate and severe. The risk for HSRs is higher in patients who report allergy to ß-lactams, moxifloxacininduced anaphylaxis, and immediate reactions than in patients who report reactions to quinolones inducing other symptoms. The usefulness of skin tests in diagnosing HSRs to quinolones is controversial, with sensitivity and specificity varying between studies. Most in vitro tests are produced in-house, with no validated commercial options. The basophil activation test has proven useful for diagnosing immediate reactions, albeit with diverse results regarding sensitivity. Drug provocation testing is currently the gold standard for confirming or excluding the diagnosis and for finding safe alternatives, although it is contraindicated in patients with severe reactions. Cross-reactivity between quinolones has proven controversial in several studies, with the lowest cross-reactivity reported for levofloxacin. Desensitization may be considered in allergy to quinolones when no other alternatives are available.

Gain-switched semiconductor lasers with pulsed excitation and optical injection for dual-comb spectroscopy

In this work we demonstrate the capability of two gain-switched optically injected semiconductor lasers to perform high-resolution dual-comb spectroscopy. The use of low duty cycle pulse trains to gain switch the lasers, combined with optical injection, allows us to obtain flat-topped optical frequency combs with 350 optical lines (within 10 dB) spaced by 100 MHz. These frequency combs significantly improve the spectral resolution reported so far on dual-comb spectroscopy with gain-switched laser diodes. We evaluate the performance of our system by measuring the transmission profile of an absorption line of H¹³CN at the C-band, analyzing the attainable signal-to-noise ratio for a range of averaging times.

Enhanced optical frequency comb generation by pulsed gain-switching of optically injected semiconductor lasers

We report on the experimental generation of broad and flat optical frequency combs (OFC) in a 1550 nm laser diode using gain switching with pulsed electrical excitation together with optical injection. The combination of both techniques allows the generation of high-quality OFCs at a repetition frequency of 500 MHz, showing a low-noise optical spectrum with unprecedent features in terms of width (108 tones within 10 dB) and flatness (56 tones within 3 dB) in comparison with those previously reported for this modulation frequency. The influence of the injection conditions on the OFC quality is studied. Using these two techniques, it has been possible to reduce the separation between tones, generating high spectral performance OFCs with a repetition rateof 100 MHz.

Consensus document on dog and cat allergy

The prevalence of sensitization to dogs and cats varies by country, exposure time and predisposition to atopy. It is estimated that 26% of European adults coming to the clinic for suspected allergy to inhalant allergens are sensitized to cats and 27% to dogs. This document is intended to be a useful tool for clinicians involved in the management of people with dog or cat allergy. It was prepared from a consensus process based on the RAND/UCLA method. Following a literature review, it proposes various recommendations concerning the diagnosis and treatment of these patients, grounded in evidence and clinical experience. The diagnosis of dog and cat allergy is based on a medical history and physical examination that are consistent with each other and is confirmed with positive results on specific IgE skin tests. Sometimes, especially in polysensitized patients, molecular diagnosis is strongly recommended. Although the most advisable measure would be to avoid the animal, this is often impossible and associated with a major emotional impact. Furthermore, indirect exposure to allergens occurs in environments in which animals are not present. Immunotherapy is emerging as a potential solution to this problem, although further supporting studies are needed.

SLIT: indications, follow-up, and management

Specific sublingual immunotherapy (SLIT) has been proved to be a safe and effective approach in respiratory allergy. However, further research is required on aspects such as patient selection, use of optimal dosing, effects on asthma, long-term effects, and management of adverse reactions. In addition, the widely heterogeneous nature of studies on SLIT performed to date and the application of the criteria for subcutaneous immunotherapy make it difficult for the prescribing clinician to draw accurate and useful conclusions. Therefore, the QUASAR Group (QUality in the Administration of SLIT in Allergic Rhinitis), which comprises allergologists with broad clinical experience in SLIT, investigated the latest research findings and available data on this approach. Working parties were formed in 3 different categories: selection of candidates for SLIT, treatment efficacy, and adverse reactions. We performed a PubMed search for articles that were representative of each category and found 850. From these, we finally selected 266 articles, which were reviewed to retrieve data on SLIT. Evidence for each clinical question was graded according to the Oxford classification. The resulting text was evaluated on 3 occasions by all the members of the group until the final version was agreed upon. In this version, we review available evidence on SLIT, particularly with pollens, which is the subject of most articles. In areas where evidence is insufficient, an alternative agreed upon by the members of the QUASAR group is presented. Finally, we propose algorithms for selecting candidates for SLIT and for management of adverse events.

Practical guidelines for diagnosing hypersensitivity reactions to nonsteroidal anti-inflammatory drugs

Nonsteroidal anti-inflammatory drugs (NSAIDs) are the drugs most frequently involved in hypersensitivity reactions. These reactions include various clinical entities with different mechanisms leading to the release of inflammatory mediators. Characterization of patients based on clinical manifestations and suspected underlying mechanisms is critical for implementation of adequate diagnostic procedures and patient management. Our objectives were to prepare a systematic review of available scientific evidence and to provide general guidelines for the diagnosis and management of patients with hypersensitivity reactions to NSAIDs. We also propose a practical algorithm for the diagnosis of specific types of hypersensitivity to NSAIDs and provide recommendations for the management of hypersensitive patients.

Genetic variants of the arachidonic acid pathway in non-steroidal anti-inflammatory drug-induced acute urticaria

BACKGROUND

To date, genetic studies of hypersensitivity reactions to non-steroidal anti-inflammatory drugs (NSAIDs) have been carried out mainly in aspirin-induced asthma and to a lesser extent in chronic urticaria, with no studies in patients with acute urticaria (AU), the most common entity induced by these drugs.

OBJECTIVE

In this work, we analysed the association of common variants of 15 relevant genes encoding both enzymes and receptors from the arachidonic acid (AA) pathway with NSAID-induced AU.

METHODS

Patients were recruited in several Allergy Services that are integrated into the Spanish network RIRAAF, and diagnosed of AU induced by cross-intolerance (CRI) to NSAIDs. Genotyping was carried out by TaqMan allelic discrimination assays.

RESULTS

A total of 486 patients with AU induced by CRI to NSAIDs and 536 unrelated controls were included in this large Spanish case-control study. Seven variants from 31 tested in six genes were associated in a discovery study population from Malaga (0.0003 ≤ p-value ≤ 0.041). A follow-up analysis in an independent sample from Madrid replicated three of the SNPs from the ALOX15 (rs7220870), PTGDR (rs8004654) and CYSLTR1 (rs320095) genes (1.055x10(-6) ≤meta-analysis p-value ≤ 0.003).

CONCLUSIONS AND CLINICAL RELEVANCE

Genetic variants of the AA pathway may play an important role in NSAID-induced AU. These data may help understand the mechanism underlying this disease.

Knowledge, attitude and adherence of Spanish healthcare professionals to asthma management recommendations during pregnancy

BACKGROUND

The aim of the present study was to evaluate the knowledge, attitude and adherence to asthma management recommendations during pregnancy of Spanish health care professionals.

METHODS

A multiple choice survey with 14 questions was designed. Items assessed opinion about asthma guidelines and attitudes towards treatment, spirometry, specific immunotherapy and labour in pregnant asthmatic patients. Test completion was voluntary, individual, and anonymous.

RESULTS

A total of 1000 questionnaires were fulfilled: respiratory medicine specialists (19.8%); allergy specialists (17.2%); primary care physicians (46.1%); and gynaecologists/obstetricians (16.9%). Guidelines were considered useful by 96.5% although 64% admitted that they followed them seldom or never. Most physicians (55.9%) answered that they would maintain asthma therapy in clinically stable patients. Almost 30% of physicians would not perform spirometry in pregnant asthma patients. 19% declared they would interrupt specific immunotherapy which had proven safe and effective. Univariate analysis revealed low adherence to be associated with the following variables: age, primary care or gynaecology/obstetrician specialisation, number of asthmatics attended per month, and declared use of guidelines for pregnant asthmatic patients. Multivariate analysis showed that being a primary care physician and a gynaecologist/obstetrician, attending a low number of asthma patients per month, and poor use of spirometry during pregnancy are associated to low adherence to asthma guidelines.

CONCLUSION

Even though the majority of Spanish physicians surveyed seem to consider guidelines useful, their adherence to those is very low if translated to managing pregnant asthmatic patients. Educational strategies seem unavoidable and should be targetted mainly to primary care and gynaecology/obstetrician physicians.

Diagnostic evaluation of patients with nonimmediate cutaneous hypersensitivity reactions to iodinated contrast media

BACKGROUND

Nonimmediate hypersensitivity reactions to iodinated contrast media (CM) are common. Allergological evaluation is necessary to confirm the diagnosis and to find a tolerated alternative. The aim of this study was to establish the role of skin testing and the drug provocation test (DPT) in the diagnosis of nonimmediate reactions to CM.

METHODS

Skin intradermal testing and patch testing with delayed readings were carried out with different CM (iobitridol, iomeprol, iodixanol, iohexol, ioversol, iopramide and ioxaglate). Single-blind placebo-controlled DPT was carried out in those cases with a negative skin test. In seven cases, a skin biopsy was obtained from positive skin tests and positive DPT.

RESULTS

Of the 161 subjects evaluated, 34 (21.1%) were skin-test positive, 21 (50%) to Iomeprol, 7 (16.7%) to Iodixanol, 5 (11.9%) to Iobitridol, 4 (9.5%) to Ioxaglate, 3 (7.1%) to Iohexol and 1 (2.4%) to Iopramide. DPT was positive in 44 cases (34.6%) that were skin-test negative, 38 (76%) to Iodixanol, 8 (16%) to Iomeprol and 4 (8%) to Iohexol. Of 78 cases (48.4%) with confirmed hypersensitivity, 34 (43.6%) were identified by skin testing and 44 (56.4%) by DPT. Skin biopsies showed a perivascular mononuclear cell infiltrate, mainly in the dermis, with higher levels of CD4 than CD8 T lymphocytes, with expression of activation markers and skin homing receptors.

CONCLUSION

Patients with nonimmediate reactions to CM were identified by skin testing in 43.6% and by DPT in 56.4%. The method to confirm the diagnosis differed depending on the CM involved.

Response to a selective COX-2 inhibitor in patients with urticaria/angioedema induced by nonsteroidal anti-inflammatory drugs

BACKGROUND

In subjects with hypersensitivity reactions with cross-intolerance to nonsteroidal anti-inflammatory drugs (NSAIDs), tolerance to selective COX-2 inhibitors has not been evaluated in large series of well-phenotyped cases.

METHODS

We evaluated 252 patients with urticaria and/or angioedema caused by hypersensitivity owing to cross-intolerance to NSAIDs. In addition to the clinical history, diagnosis was confirmed by provocation to an alternative NSAID. Two groups were considered: (A) patients with cross-intolerance to NSAIDs and intolerance to paracetamol and (B) patients with cross-intolerance to NSAIDs and good tolerance to paracetamol. Etoricoxib was administered to Group A patients and to a representative sample of Group B patients. In the event of a positive response, serum tryptase levels were determined and skin biopsy was performed in five patients in each group.

RESULTS

Ibuprofen was the most commonly implicated drug, followed by acetylsalicylic acid (ASA). Urticaria was the most common manifestation, followed by angioedema. Most of the patients developed symptoms within 1 h. Twenty-five percent in Group A (n = 47) and 6% in Group B (n = 50) were intolerant to etoricoxib. Skin biopsy showed mast cell activation with the release of tryptase to the extracellular space but without the increase in serum tryptase levels.

CONCLUSION

Selective COX-2 inhibitors may be unsafe in subjects with urticaria and/or angioedema caused by hypersensitivity reactions to NSAIDs with cross-intolerance if they are intolerant to paracetamol. A quarter of patients who were intolerant to this drug were also intolerant to etoricoxib. In subjects with hypersensitivity to NSAIDs and intolerance to paracetamol, selective COX-2 inhibitors should be administered as a controlled, incremental dose provocation test to assess tolerance.

Characteristics of subjects experiencing hypersensitivity to non-steroidal anti-inflammatory drugs: patterns of response

BACKGROUND

Non-steroidal anti-inflammatory drugs (NSAIDs) are one of the most frequently involved groups of medicines in hypersensitivity drug reactions. Two mechanisms can induce the reaction: immunological (sensitization) due to a specific IgE or T cell response and pharmacological (cyclooxygenase inhibition). The contribution of each of these mechanisms to the reactions is not well known.

OBJECTIVE

To analyse a large group of subjects with confirmed hypersensitivity reactions to NSAIDs.

METHODS

The drugs involved, the clinical entities induced and the time interval between drug intake and appearance of the reaction were studied. In cases where the diagnosis was not confirmed, a drug provocation test was carried out. Atopy status was also assessed with prick test and total IgE in serum.

RESULTS

A total of 659 patients were finally considered to have had hypersensitivity reactions to NSAIDs; 76% had cross-intolerance (CI) and 24% were selective responders (SR). The most important drugs involved in CI were propionic acid derivatives, in most cases ibuprofen, and in SR pyrazolones. In CI, the most frequent clinical entity was urticaria and angio-oedema and to a lesser extent airway involvement. The skin and airways were both involved in an important proportion of cases. The most frequent entities in SR were urticaria and/or angio-oedema followed by anaphylaxis. Atopy was significantly associated in the CI group (P<0.005).

CONCLUSION AND CLINICAL RELEVANCE

Cutaneous hypersensitivity reactions by CI to NSAIDs are the most frequent entities induced by these compounds. In addition to aspirin, other NSAIDs are taking on a predominant role. Atopy can be a predisposing factor in patients with CI.

Identification of soluble forms of vascular endothelial growth factor receptors, sVEGFR-1 and sVEGFR-2, in bovine dominant follicles

The development of dominant follicles requires the parallel growth of a vascular network, regulated by VEGF and its receptors VEGFR-1 and VEGFR-2. Here, we demonstrate the presence of mRNA for the soluble forms of VEGFR-1 and VEGFR-2 by RT-PCR and the respective proteins by Western blot, in bovine dominant follicles. The 3' end of the mRNA coding region and the deduced C-terminal amino acid sequence of the bovine VEGFR soluble forms were similar to those previously described in human and mice. The relative abundance of sVEGFR-1 was higher in dominant follicles of day 4, decreasing on day 6 and further on day 9 of the cycle. In contrast, sVEGFR-2 expression was low on day 4 follicles and increased as the cycle advanced, becoming greater on day 9. The changes of sVEGFR-1 and sVEGFR-2 with the age of the bovine dominant follicle indicate a physiological role in its growth and atresia.

In vitro evaluation of IgE-mediated hypersensitivity reactions to quinolones

BACKGROUND

  Hypersensitivity IgE-mediated reactions to quinolones are not easy to diagnose, with skin testing inducing false positive results. The aim of the study was to evaluate the in vitro-specific IgE response in patients with immediate allergic reactions to quinolones.

METHODS

  We evaluated 38 patients with confirmed immediate allergic reactions to quinolones. Those with anaphylaxis were considered allergic by clinical history, once other possible causes were ruled out, and those with urticaria by drug provocation. Sepharose-radioimmunoassay (RIA) and basophil activation test (BAT) with ciprofloxacin, moxifloxacin and levofloxacin were performed.

RESULTS

  The quinolones involved were moxifloxacin (N = 24), ciprofloxacin (N = 11) and levofloxacin (N = 3). Sepharose-RIA was positive in 12 cases (31.57%) and BAT in 27 (71.05%). With Sepharose-RIA, 8 (21%) were positive to ciprofloxacin, 7 (18.4%) to moxifloxacin and 7 (18.4%) to levofloxacin. With BAT, 23 (60.5%) were positive to ciprofloxacin, 12 (31.6%) to moxifloxacin and 8 (21%) to levofloxacin. The specificity of the Sepharose-RIA was demonstrated by inhibition tests. To confirm that the BAT results observed were IgE mediated, the PI3K inhibitor wortmannin was used, with this compound inhibiting the BAT when stimulated with anti-IgE and the different quinolones, but not when fMLP was used as the basophil stimulator. Sepharose-RIA and BAT were repeated in positive cases 1 year later, detecting a decrease in all cases, with four becoming negative.

CONCLUSION

  Immediate hypersensitivity reactions to quinolones do occur, with moxifloxacin being the drug most frequently involved. The BAT is a useful method for diagnosing patients. Specific IgE was demonstrated by Sepharose-RIA and inhibition assay.

P and R wave detection in complete congenital atrioventricular block

Complete atrioventricular block (type III AVB) is characterized by an absence of P wave transmission to ventricles. This implies that QRS complexes are generated in an autonomous way and are not coordinated with P waves. This work introduces a new algorithm for the detection of P waves for this type of pathology using noninvasive electrocardiographic surface leads. The proposed algorithm is divided into three stages. In the first stage, the R waves located by a QRS detector are used to generate the RR series and time references for the other stages of the algorithm. In the second stage, the ventricular activity (QT segment) is removed by using an adaptive filter that obtains an averaged pattern of the QT segment. In the third stage, a new P wave detector is applied to the residual signal obtained after QT cancellation in order to detect P wave locations and get the PP time series. Eight Holter records from patients with congenital type III AVB were used to verify the proposed algorithm. Although further improvements should be made to improve the algorithm's performance, the results obtained show high average values of sensitivity (90.52%) and positive prediction (90.98%).

[Allergic contact dermatitis from lidocaine in ear drops]

Lidocaine is one of the most widely used local anesthetics. It can be administered topically or parenterally. Allergic contact dermatitis from lidocaine is uncommon, but an increasing number of cases have been reported in recent years. We present the case of a 66-year-old man who presented with acute dermatitis on the pinna and left cheek after applying ear drops. Patch tests were positive for the product itself and for lidocaine in the ear drops, thereby confirming the diagnosis of contact dermatitis from lidocaine.

Superoxide dismutase, catalase, and glutathione peroxidase in the testis of the Mexican big-eared bat (Corynorhinus mexicanus) during its annual reproductive cycle

The reproductive physiology of Corynorhinus mexicanus includes a testes growth-involution cycle. Testis recrudescence begins in May-June, peaks in August and then undergoes a profound involution being totally regressed in November. Adult, male individuals were captured monthly during one year and ROS scavenging enzyme activities were measured in testes and expressed per total wet-weight and per mg protein. SOD total activity is very low from October to February; increases sharply one full month before testes recrudescence starts, and in August, when testis activity was at its peak, SOD is 3-4 times lower than in July. Catalase total activity is bimodal. The main peak of activity occurs during testicular recrudescence with an additional smaller peak, two months before the onset of recrudescence. Glutathione peroxidase total activity parallels almost exactly the testis growth cycle, increases in July, reaches a peak in August and decreases through September to almost disappear in October. SOD specific activity shows a pre-testicular increase of activity, maintains its activity from March to July and then descends drastically to almost nil in August, maintaining these low values until February. Catalase specific activity is particularly important during the period of testicular regression. GPX specific activity is low from March to July, months of testicular recrudescence; whereas its activity increases in August and peaks in November, when testes regression occurs. Our data show that ROS-scavenging enzymes may play a very important role during testes involution-recrudescence in C. mexicanus, and we believe their participation could be equally important in all seasonally breeding mammals.

146 EFFECT OF MATERNAL AGE AND PARITY ON THE PRESENCE AND DISTRIBUTION OF CADHERIN-E IN HAMSTER EMBRYOS DURING PRE-IMPLANTATION DEVELOPMENT AND TRANSPORT

Our knowledge of the factors that contribute to in vivo embryo development and transport are still incomplete. Although there is solid evidence that the hormonal state of the female regulates ovum transport in mammals, recently, because of significant differences between the rate of oviduct transport of fertilized and unfertilized eggs in several mammalian species, there have been some reports showing that the conceptus itself may auto regulates its own transport. During the initial phases of embryonic development the distribution of E-cadherin, a calcium dependent cell adhesion molecule, changes from a general distribution over the whole surface of the blastomeres to become almost exclusively localized over the points of contact between blastomeres. This change on E-cadherin localization has been related to the beginning of embryo compactation and is considered as the initial stage of differentiation. We have recently shown that pre-implantation embryo development and transport is highly synchronous in nuliparous young females (NYF), but not in adults. Nuliparous adult (8 months) females (NAF) and multiparous adult females (MAF) show significant asynchrony and retard on early embryo development. In NYF, all 8 cells embryos reached the uterus by 62 h after coitus. In adult females, both nuliparous and multiparous, a considerable number of 8 cells embryos fail to migrate into the uterus even at 67 h after coitus. E-cadherin distribution was studied by indirect immunofluorescence and confocal microscopy during preimplantation embryo development in three groups, NYF, MAF, and NAF, of regularly cycling golden hamster (Mesocricetus auratus) females. Females were mated with males of proven fertility. Only 15 minutes were allowing for mating. Time of ejaculation was registered. Females were sacrificed from 60 to 69 h after coitus. Corpora lutea were counted in both ovarian surfaces. Oviducts and uterine horns were flushed separately and embryo number, stage of development, and distribution were recorded. Cell numbers, cadherin distribution and the number of cadherin-dependent cell to cell contacts were established in at least 20 embryos per group and at each of the different hours of the study. Presence and distribution of E-cadherin on 4-, 6-, and 8-cell blastomeres embryos differs accordingly with the parity and age of the females. Differences are particularly important at the eight-cell stage 80 to 93% of the embryos from NYF showed normal cadherin dependent cell contacts with all neighboring cells. In the case of multiparous adult females (MAF) only 52 to 68% of the embryos showed normal cell to cell contacts. These results will be discussed in relation to the respective role that the female hamster and the conceptus itself play in early embryo development and transport. Our results also indicate that in spite of the significantly higher ovulation rate of old females, their reproductive efficiency were significantly lower than that of NYF.

Superoxide dismutase, catalase, and glutathione peroxidase during epididymal maturation and prolonged storage of spermatozoa in the Mexican big-eared bat (Corynorhinus mexicanus)

We studied the activities of reactive oxygen species (ROS) scavenging enzymes during epididymal spermatozoon maturation and storage in Corynorhinus mexicanus (G.M. Allen, 1916), a vespertilionid bat that stores spermatozoa in the epididymides for several months after regression of the testes. Depending on the phase of the epididymal reproductive cycle, two different patterns of antioxidant enzyme activities were observed in C. mexicanus. Catalase activity is clearly present in both caput and cauda epididymides throughout the entire annual reproductive cycle, being particularly high during the post-testicular phase of epididymal function. Superoxide dismutase (SOD) activity, present during the testicular phase of epididymal transport and maturation of spermatozoa, is almost completely absent or inhibited in both epididymal segments during the post-testicular epididymal storage period. GPx activity is low during the testicular phase of epididymal spermatozoon maturation and is high in both epididymal segments during the storage phase of epididymal function. From our results, we postulate that (i) the pattern of epididymal antioxidant enzyme activities in C. mexicanus is significantly different from the pattern that is proposed to be unique for mammals; (ii) epididymal function in these species of bats can be clearly divided into two phases, a testicular-dependent phase that is related to the spermatozoon maturation function of the epididymides and a testicular-independent phase that is related to the long-term spermatozoon storage function observed in these mammals; (iii) the study of the regulation of the redox potential of the microenvironment, associated with mammalian spermatozoa as they transit through the epididymides, must be particularly focused on the anatomical region where ROS generation scavenging and spermatozoon maturation storage processes take place.

Effect of maternal age and parity on preimplantation embryo development and transport in the golden hamster (Mesocricetus auratus)

Preimplantation embryo development was studied in the golden hamster (Mesocricetus auratus). Three groups of regularly cycling female hamsters were used: (I) 30 nulliparous young female (NYF) hamsters; (II) 24 nulliparous adult female (NAF) hamsters and (III) 30 multiparous adult female (MAF) hamsters. Female hamsters were mated with male hamsters of proven fertility. Only 15 min were allowed for mating. The moment of ejaculation was registered. Female hamsters were killed from 60 to 69 h after coitus. Corpora lutea were counted in both ovarian surfaces. Oviducts and uterine horns were flushed separately and embryo number, stage of development and distribution were recorded. Adult female hamsters, nulliparous and multiparous, had significant higher ovulation rates than NYF, but their reproductive efficiency was significantly lower. Preimplantation embryo development and transport were highly synchronous in NYF, but not in adults. Morulae were observed in NYF as early as 62-63 h after coitus. In adult female hamsters, significant numbers of morulae were found until 66-67 h. On the contrary, in NYF four-cell embryos were detected only until 60-61 h, while four-cell embryos were found until 64-65 h in NAF, and until 66-67 h in MAF. Embryo transport from the oviduct to the uterus is practically completed at 62-63 h after coitus in NYF, while it is evidently retarded in adult animals. In NYF all eight-cell embryos reached the uterus by 62 h after coitus. In adult female hamsters, both nulliparous and multiparous, a considerable number of eight-cell embryos fail to migrate into the uterus even at 67 h after coitus.

Changes in the quality of rabbit semen in 14 consecutive ejaculates obtained every 15 minutes

Modifications of semen quality related to ejaculation frequency is one of the most important and neglected factors from the standpoint of artificial insemination or sperm competition. New Zealand white rabbits (Oryctolagus cuniculus) offer an advantageous experimental model because they have characteristic sexual behavior, they present rapid ejaculation after a single intromission, they have a very short interval between successive ejaculations, and semen can be easily collected. The authors studied the modifications on sperm quality (semen volume, sperm concentration, sperm motility) produced by 14 consecutive ejaculations recovered every 15 min using stimulus females and an artificial vagina. Bucks were exposed every 15 min to a sexually receptive female. After each ejaculation the female was removed and reintroduced 15 min later. Sperm concentration showed a clear biphasic conduct. The amount of spermatozoa per milliliter decreased rapidly until ejaculate number 6, showed a highly significant increase in ejaculates 7-9, and decreased to nil in the last 2 ejaculates. Total number of ejaculated spermatozoa was 557 x 10(6), 76% of which were recovered from the first 4 ejaculates. Ejaculate volume also showed a biphasic conduct. In the first ejaculates the volume decreased linearly until ejaculate number 6, showed a significant increase in ejaculates 7-10, and then decreased. The total semen volume recovered during the experiment was 2.44 mL, 40% of which (0.98 mL) was recovered from the first 2 ejaculates. Individual motility in the first 6 ejaculates was preferentially progressive (60% of the sperms) and turned to random or in situ from the seventh ejaculate up. The proportion of spermatozoa with cytoplasmic droplets increased from ejaculates 6 and 7 up. The results seem to reflect an acceleration of semen transport through the epididymis when the demands for spermatozoa increase.