Surveying vendors of street-vended food: a new methodology applied in two Guatemalan cities

Lack of reliable data about street vendors, who are difficult to survey, has hampered efforts to improve the safety of street-vended food. A two-phase method for sampling vendors, surveying first in areas of concentrated vending activity identified by local authorities and second in randomly selected areas, was developed and implemented in two Guatemalan cities where street-vended food had been implicated in cholera transmission. In a 4-day survey in Escuintla, 59 vendors (42 from phase 1, 17 from phase 2) were interviewed. They demonstrated good knowledge of food safety and cholera but unsafe practices, implying that more effective, practical training was needed. In a 6-day survey in Guatemala City, 78 vendors (77 from phase 1, 1 from phase 2) were interviewed. Sixty-eight (87 %) vendors stored water, usually in wide-mouthed vessels prone to contamination; this led to a field test of a new system for safe water storage. Useful information for public health planning and intervention can be gathered rapidly with this new method for surveying street vendors.

Relationship between fertilization results after intracytoplasmic sperm injection, and intrafollicular steroid, pituitary hormone and cytokine concentrations

Previous studies relating hormone and cytokine concentrations in follicular fluid to oocyte fertilizability were flawed by the uncertainty about the actual oocyte maturity status at the time of recovery and by the possible contribution of the male factor to failures of conventional in-vitro fertilization. This is the first study in which oocyte maturity was assessed immediately after recovery and only mature oocytes were selected for treatment by intracytoplasmic sperm injection. Fertilization outcomes were related to follicular fluid concentrations of 17beta-oestradiol, progesterone, follicle stimulating hormone, luteinizing hormone (LH), growth hormone (GH), prolactin (PRL), interleukin-1 (IL-1) and tumour necrosis factor-alpha (TNF alpha). Those oocytes that subsequently showed normal fertilization were harvested from follicles with higher concentrations of progesterone, GH, PRL, IL-1 and TNF alpha as compared with those of oocytes that failed to fertilize. Among the normally fertilized oocytes, low GH concentrations were associated with the failure of cleavage and with poor morphology of cleaving embryos, whereas rapidly cleaving embryos developed from oocytes recovered from follicles with high concentrations of LH and IL-1. These data suggest important roles for GH, IL-1 and TNF alpha, and of residual LH after pituitary suppression, as positive regulators of the final phase of oocyte intrafollicular development.

[Incidence of Plesiomonas shigelloides in tilapia tetrahibrids (Oreochromis sp.)]

Plesiomonas shigelloides, a member of the family Vibrionaceae, is a Gram negative rod associated with several gastroenteritis outbreaks, especially in tropical and subtropical countries. In same way, it has been related to some septicemia, meningitis and cholecystitis cases. The microorganism is normally found in water, fish and birds. The aim of this work was to study the incidence of Plesiomonas shigelloides in tetrahybrids of Oreochromis sp. (Pink Tilapia) located at the central region of Venezuela. Once the samples were homogenized, the techniques of enrichment and direct streaking were used simultaneously for the isolation of the microorganism. A high incidence of P. shigelloides was determined (73%), being higher in the intestinal tract (60%), followed by the skin (36.7%) and the gills (26.67%), without any correlation among them. In the fish pond, the microorganism isolation frequency was 41.67%. The direct streaking technique presented the highest isolation values in the different Tilapia tissues (60%) and in the water as well (41.60%). No significant differences were observed on the effectivity of the selective agars used for the isolation of P. shigelloides (Plesiomonas Agar and Inositol-Brilliant Green-Bile Salts Agar). A positive correlation was observed between the microorganism incidence and the pluviosity levels. A high incidence of E. coli was observed in the samples of Tilapia tissues and the water pond. No correlation was observed between incidence of P. shigelloides and E. coli. Due to the high prevalence of P. shigelloides found in the present study, it is important to assure a proper evisceration, washing and storage at temperatures lower than 8 degrees C, and a proper product cooking to diminish the customeris risk.

Stimulation of tyrosine phosphorylation by progesterone and its 11-OH derivatives: dissection of a Ca(2+)-dependent and a Ca(2+)-independent mechanism

Progesterone has previously been shown to exert non-genomic effects on human spermatozoa by opening plasma membrane ion channels and by stimulating protein tyrosine phosphorylation. Here we examined how these two activities are influenced by 11-hydroxyl substitution of the steroid molecule either in the alpha- or in the beta-configuration. Both the 11alpha-OH and the 11beta-OH derivatives of progesterone were more effective than progesterone in stimulating tyrosine phosphorylation, although 11alpha-OH-progesterone was a markedly weaker Ca(2+)-influx inducing agonist than the other two steroids. In Ca(2+)-containing medium, the agonist activity of the 11alpha-OH derivative was weaker than that of the 11beta-OH derivative, and it was completely abolished by genistein, whereas that of progesterone and its 11beta-OH derivative was inhibited only partly by this drug. In contrast, when applied in Ca(2+)-free medium, the 11alpha-OH derivative was the strongest of the three agonists tested, and the effects of all the three steroids were completely abolished by genistein. These data show that the structural motifs of steroid molecules that are responsible for the stimulation of tyrosine phosphorylation are different from those mediating the steroid action on Ca2+ influx through plasma membrane channels. The synthesis of selective agonists of both activities may lead to the development of new pharmacological agents to be used in the treatment of steroid-dependent pathologies.

Estradiol modulates breast cancer cell apoptosis: a novel nongenomic steroid action relevant to carcinogenesis

It is known that steroids can induce cell surface receptor aggregation followed by activation of receptor and nonreceptor tyrosine kinases. It has been shown recently that 17beta-estradiol (E2) can stimulate the Src/p21ras/mitogen-activated protein kinase pathway in breast cancer cells, and this effect is supposed to mediate the E2-induced stimulation of breast cancer cell proliferation, possibly via activation of the c-fos and c-jun early genes or of genes involved in cell cycle control. Here we demonstrate the existence of an alternative mechanism of the cancer-promoting effect of E2. Human breast cancer cells (MCF-7) were exposed to the known proapoptotic agent vitamin E succinate (VES), added alone or together with different concentrations of E2. E2 conjugated with bovine serum albumin (E2-BSA), which cannot cross the plasma membrane of living cells, was also used in some experiments to assess whether E2 acted on the cell surface or at intracellular receptors. Apoptosis was analyzed by fluorescence-activated cell sorting after cell staining with propidium iodide and FITC-labeled annexin V. E2 showed a concentration-dependent stimulatory effect on spontaneous apoptosis but inhibited the VES-induced apoptosis. However, effects produced by the same molar concentrations of E2 were different when the hormone was free and when it was used in the form of the E2-BSA conjugate. The effects of E2 and E2-BSA were sensitive to genistein, a tyrosine kinase inhibitor. These data show that E2 modulates apoptosis of breast cancer cells, probably acting both at the cell surface and inside the cells. Tyrosine phosphorylation is involved in the signaling pathways mediating this E2 effect.

Treatment of severe male infertility by micromanipulation-assisted fertilization: news and views

Recent progress in cell micromanipulation has made it possible to achieve fertilization even with highly deficient male gametes, by injecting them directly to oocyte cytoplasm. This technique, known as intracytoplasmic sperm injection (ICSI), has proved efficient in most types of sperm pathology. However, ICSI fails when injected spermatozoa are not capable of supporting the process of oocyte activation or when they carry genetic abnormalities incompatible with normal embryonic development. Abnormalities of oocyte activation and the transmission of genetic anomalies to the progeny are also two major concerns relating to the clinical use of ICSI. The use of micromanipulation-assisted fertilization in cases of male germ cell maturation arrest, namely fertilization by round spermatid injection (ROSI), has brought preliminary clinical results, and the improvement of ROSI clinical efficacy remains a major challenge for future research.

Long-term survival in patients with ovarian metastases from colorectal carcinoma

BACKGROUND

Ovarian metastases (OM) are a relatively uncommon consequence of primary colorectal carcinoma (CRC). The authors present a retrospective review of the impact of elective and therapeutic oophorectomy on the natural history of CRC.

METHODS

Patients with primary CRC from January 1964 through March 1996 were reviewed. Survival from the time of OM diagnosis was estimated by the Kaplan-Meier method; differences between groups were based on the log-rank test.

RESULTS

A total of 155 patients were studied. Synchronous OM occurred in 90 patients (58.1%); metachronous OM occurred in 65 patients (41.9%). Estimated 5-year survival for patients with synchronous OM was 9%, versus 20% for metachronous OM (P < .0001). Resection of metastatic disease was associated with an improved 5-year survival for synchronous OM (15% vs. 0%, P=.0001) and metachronous OM (24% vs. 0%, P < .0001) if patients were disease-free postoperatively. Other clinical characteristics, including age, menopausal status, stage, and location of primary tumor, had no significant impact on survival.

CONCLUSIONS

Ovarian metastases from colorectal carcinoma are associated with a poor outcome. Although there is no survival advantage associated with resection of occult microscopic disease, long-term survival is possible if patients are rendered surgically disease-free.

Human spermatogenesis in vitro: respective effects of follicle-stimulating hormone and testosterone on meiosis, spermiogenesis, and Sertoli cell apoptosis

In spite of the availability of abundant data about in vitro spermatogenesis in laboratory animals, studies on human in vitro spermatogenesis are scarce. This study employed a relatively simple culture system, involving all cell types of seminiferous tubules, to analyze the effects of FSH and testosterone (T) on different characteristics of human germ and Sertoli cells in culture. By using fluorescence in-situ hybridization, we show that in vitro reduction of germ cell ploidy can be stimulated by FSH but not by T. FSH, but not T, also induced unexpectedly rapid (24-48 h) morphological changes resembling spermiogenesis, although individual changes (spermatid nucleus condensation and protrusion, cell body elongation, and flagellar growth) proceeded in an uncoordinated way and mostly resulted in the development of abnormal forms of elongated spermatids. Though ineffective alone, T potentiated the effects of FSH on meiosis and spermiogenesis. These effects of T were probably caused by the prevention of Sertoli cell apoptosis, an effect that could not be mimicked by FSH. These data show that, in the presence of high concentrations of FSH and T, human spermatogenesis can proceed in vitro with an unusual speed, but the resulting gametes are morphologically abnormal. The potential practical relevance of these findings to assisted reproduction remains to be assessed.

Effect of genetically modified, low-phytic acid maize on absorption of iron from tortillas

BACKGROUND

Genetically modified, low-phytic acid strains of maize were developed to enhance mineral absorption, but have not been tested previously in humans.

OBJECTIVES

We evaluated the mineral and phytic acid contents of a low-phytic acid "flint" maize (LPM, the lpa-1-1 mutant) and its parent, wild-type strain (WTM) and measured iron absorption from tortillas prepared with each type of maize and from a reference dose of ferrous ascorbate.

DESIGN

Proximate composition and mineral and phytic acid contents were measured by standard techniques. Iron absorption from tortillas was evaluated by using the extrinsic tag method and was measured as the incorporation of radiolabeled iron into the red blood cells of 14 nonanemic men 2 wk after intake.

RESULTS

The phytic acid content of LPM was 3.48 mg/g, approximately 35% of the phytic acid content of WTM; concentrations of macronutrients and most minerals were not significantly different between strains. Iron absorption results were adjusted to 40% absorption of ferrous ascorbate. Iron absorption was 49% greater from LPM (8.2% of intake) than from WTM (5.5% of intake) tortillas (P < 0.001, repeated-measures analysis of variance).

CONCLUSION

Consumption of genetically modified, low-phytic acid strains of maize may improve iron absorption in human populations that consume maize-based diets.

Differentiation of spermatogenic cells during in-vitro culture of testicular biopsy samples from patients with obstructive azoospermia: effect of recombinant follicle stimulating hormone

In-vitro differentiation of spermatogenic cells is a potential approach to the treatment of male sterility due to spermatogenic arrest. This is a pilot study evaluating meiotic, morphogenetic and cytoplasmic maturation of spermatogenic cells from 18 patients with obstructive azoospermia, during in-vitro culture of partly disintegrated testicular biopsy samples in the presence or absence of recombinant follicle stimulating hormone (rFSH). Meiotic progression was detectable only in the presence of rFSH in culture medium. FSH-dependent condensation, peripheral migration and protrusion of spermatid nuclei, together with FSH-independent flagellar growth, were the main events indicating post-meiotic sperm cell differentiation. rFSH also promoted the progression of spermatid cytoplasmic maturation, reflected by acceleration of acrosomal development. These differentiation events appeared to be mediated by humoral activity of Sertoli cells, without the need for a direct Sertoli-sperm cell contact. These findings provide a background for similar studies in patients with non-obstructive azoospermia. If reproducible in the latter group, transmeiotic in-vitro differentiation of primary spermatocytes may be useful in cases of complete maturation arrest, whereas the development of culture-specific forms may help select viable spermatids in cases of complete spermiogenesis failure.

Human infection with Trypanosoma cruzi induces parasite antigen-specific cytotoxic T lymphocyte responses

Experimental models of Chagas' disease, an infection caused by the intracellular protozoan Trypanosoma cruzi, have demonstrated the crucial immunoprotective role played by CD8(+) T lymphocytes. These cells dominate inflammatory foci in parasitized tissues and their elimination from mice leads to uncontrolled parasite replication and subsequent death of the infected host. A trypomastigote surface antigen, TSA-1, and two amastigote surface molecules, ASP-1 and ASP-2, were recently identified as targets of CD8(+) cytotoxic T lymphocytes (CTL) in T. cruzi-infected mice. Until now, however, there was no evidence for the development of parasite-specific CTL in T. cruzi-infected humans. In this study, human CTL specific for TSA-1-, ASP-1-, and ASP-2-derived peptides were detected in the peripheral blood mononuclear cells from 21 of 24 HLA-A2(+) T. cruzi-infected patients. CTL recognition was antigen specific, A2-restricted, and CD8(+) T cell-dependent. Demonstration of human CTL against T. cruzi and against target molecules identified using the murine model provides important information for the optimal design and evaluation of vaccines to prevent or ameliorate Chagas' disease.

Germ cell apoptosis in men with complete and incomplete spermiogenesis failure

Germ cell apoptosis was evaluated in 11 men suffering from nonobstructive azoospermia and enrolled in a spermatid conception programme. In six of these patients, round spermatids (Sa stage) were the most advanced spermatogenic cells recovered from testicular biopsy samples. This condition is referred to as complete spermiogenesis failure. In the remaining five men, a few late elongated spermatids (Sd stage) were unexpectedly found in the testicular biopsy samples on the day of treatment. This condition is referred to as incomplete spermiogenesis failure. Germ cell apoptosis in both groups of patients was examined by analysing cell smears prepared from mechanically disintegrated testicular tissues using terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL), which detects apoptosis-specific DNA fragmentation, and annexin-V binding, detecting apoptosis-related translocation of plasma membrane phosphatidylserine to the membrane's outer surface. Both methods were combined, in double-fluorescence labelling preparations, with immunocytochemical detection of proacrosin, a specific germline marker. Patients with complete spermiogenesis failure had significantly higher frequencies of primary spermatocytes and round spermatids carrying the apoptosis-specific DNA damage in comparison with patients with incomplete spermiogenesis failure. Surprisingly, apoptosis-related phosphatidylserine externalization occurs rarely until the advanced stages of spermiogenesis. Since externalized phosphatidylserine is expected to be involved in the recognition of apoptotic cells by phagocytes, apoptotic spermatocytes and round spermatids may not be removed easily by phagocytosis. The high frequency of DNA damage in round spermatids from patients with complete spermiogenesis failure explains the low success rates of spermatid conception in these cases. The evaluation of apoptosis can help predict success rates of spermatid conception.

Spermatids as gametes: indications and limitations

The feasibility of achieving viable embryos, developing to term after transfer into the uterus, by fertilizing oocytes with spermatids has been demonstrated both in animal studies and in preliminary human clinical trials. Here we review the current clinical indications of spermatid conception and discuss the predictable success rates associated with each of these indications. Potential health hazards relating to the use of spermatids for conception are updated taking into account the risk of abnormal or incomplete epigenetic modifications of newly discovered human imprinted genes. We also add new experimental data showing the occurrence of spermatids in patients lacking spermatozoa and demonstrating that round spermatids recovered from patients with complete spermiogenesis failure (no elongated spermatids or spermatozoa ever detected in the patient's history) are often deficient in the factor(s) responsible for oocyte activation. The possible consequences of this deficiency for the occurrence of abnormal fertilization patterns and for the impairment of further preimplantation and post-implantation development are discussed. It is concluded that the development of diagnostic tests to assess the intrinsic quality of spermatids, with regard to their ability to act as gametes, is urgently needed as part of pre-treatment diagnosis before infertile couples are included in a spermatid conception programme. Centres wishing to use spermatids in human assisted reproduction should also be prepared to offer adequate diagnostic methods to control genomic imprinting abnormalities in the progeny.

Atypical microangiopathy in a patient treated with ticlopidine

Microangiopathies are rare complications during treatments with ticlopidine. We describe an atypical microangiopathy, affecting almost exclusively myocardium, and thrombocytopenia, shortly after onset of ticlopidine. The patient died a few days after. Autopsy showed no bleedings or large thrombi in most organs, but were compatible with microangiopathy in myocardial small vessels.

Theoretical description of the polymerase chain reaction

Taking into account expressions for the efficiency of the polymerase chain reaction (PCR) recently deduced from enzymological considerations, and making use of a continuous model based on the law of mass action, closed form solutions are derived that enable a complete description of the standard and quantitative competitive PCR methods. The resulting behaviour is in reasonable agreement with that from a previous, empirical, discrete approach; but the latter is nonetheless shown to overestimate the amplification yield by as much as 30% due to the weak assumption of a constant efficiency during the cycle duration. The present formalism will facilitate the implementation of accurate fitting procedures of experimental data to manage quantification.

Orthostatic sympathetic derangement in subjects with fibromyalgia

OBJECTIVE

To assess the sympathetic-parasympathetic balance in individuals with fibromyalgia (FM), and its response to orthostatic stress, by power spectral analysis of heart rate variability.

METHODS

We studied 19 women with FM and 19 age matched controls. A high resolution electrocardiogram was obtained in supine and standing postures after achieving a stable heart rate. Spectral analysis of R-R intervals was done by the fast Fourier transform algorithm.

RESULTS

Analyses of the different frequency components revealed significant difference between the 2 groups in the low frequency (0.050-0.150 Hz) band, which reflects modulation of the sympathetic nervous system. Controls displayed an increased power spectral density upon standing (+0.081 +/- 0.217 Hz); individuals with FM had a discordant response (-0.057 +/- 0.097 Hz) (p = 0.018).

CONCLUSION

In FM, there is a deranged sympathetic response to orthostatic stress. This abnormality may have implications regarding the pathogenesis of FM.

Direct non-genomic effects of follicular steroids on maturing human oocytes: oestrogen versus androgen antagonism

Previously published data have suggested that oestradiol exerts direct beneficial effects on human oocytes during in-vitro maturation and that these effects are at least partly due to a non-genomic action of the steroid at the oocyte surface. Here we provide evidence showing that a non-genomic effect of oestradiol is counteracted by androstenedione. In contrast to these results from in-vitro experiments, in which changes in steroid concentrations are abrupt and the non-genomic responses are rapid, the progressively changing follicular steroid concentrations which occur during in-vivo development may rather have permissive or restrictive effects on the events of spontaneous oocyte cytoplasmic maturation. The oocyte is particularly sensitive at the germinal vesicle stage of development to non-genomic steroid actions. Ovarian stimulation protocols should thus be adjusted so as to avoid androgen predominance at the mid-follicular phase. In patients in whom this condition cannot be met, in-vitro maturation of oocytes may be a solution.

Enzymological considerations for a theoretical description of the quantitative competitive polymerase chain reaction (QC-PCR)

The enzymological principles of the polymerase chain reaction (PCR) and of the quantitative competitive PCR (QC-PCR) are developed, proposing a theoretical framework that will facilitate quantification in experimental methodologies. It is demonstrated that the specificity of the QC-PCR, i.e. the ratio of the target initial velocity to that of the competitor template, remains constant not only during a particular amplification but also for increasing initial competitor concentrations. Linear fitting procedures are thus recommended that will enable a quantitative estimate of the initial target concentration. Finally, expressions for the efficiency of the PCR and QC-PCR are derived that are in agreement with previous experimental inferences.

The occurrence and identification of round spermatids in the ejaculate of men with nonobstructive azoospermia

OBJECTIVE

To evaluate the occurrence of round spermatids in the ejaculate of men suffering from nonobstructive azoospermia as a prerequisite for the therapeutic use of round spermatid injection into oocytes.

DESIGN

Prospective study.

SETTING

University-based diagnostic and research laboratory.

PATIENT(S)

Azoospermic men previously thought to be definitively infertile whose cases were revisited in view of the novel method of fertilization by round spermatid injection into oocytes.

INTERVENTION(S)

Smear preparations of cells from patients' ejaculates were stained by three different methods: Papanicolaou, fluorescein-labeled Pisum sativum agglutinin binding, and antiacrosin antiserum immunolabeling.

MAIN OUTCOME MEASURE(S)

Search for round spermatids in smear preparations of cells from azoospermic ejaculates.

RESULT(S)

Of 124 azoospermic men examined, 36 (69%) had round spermatids in the ejaculate. the quantity of round spermatids was not related to serum FSH concentration.

CONCLUSION(S)

Variable quantities of round spermatids can be detected in the ejaculate of most patients with nonobstructive azoospermia. High serum FSH levels do not predict the absence of spermatids.

Calcium responses of human oocytes after intracytoplasmic injection of leukocytes, spermatocytes and round spermatids

Oocyte activation in mammals involves the action of a soluble sperm factor (SSF) that enables oocytes to develop a characteristic series of Ca2+ spikes (Ca2+ oscillations). SSF is also likely to be responsible for the Ca2+ oscillations driving oocyte activation after intracytoplasmic sperm injection [ICSI]. With an appropriate injection technique, Ca2+ oscillations do not develop spontaneously after ICSI but can be triggered by subsequent treatment of sperm-injected oocytes with Ca2+ ionophore. Here we show that Ca2+ oscillations, quite similar to those developing after ICSI, can be triggered by the ionophore treatment in human oocytes previously injected with human round spermatids. In contrast, oocytes injected with earlier spermatogenic cell (primary and secondary spermatocytes) and with non-germ cells (polymorphonuclear leukocytes) did not develop Ca2+ oscillations after the ionophore challenge although the subsequent injection of SSF did induce typical Ca2+ oscillations in these oocytes. Disintegration of the plasma membrane of the injected cells was detected in all cases by transmission electron microscopy. Thus, the absence of the typical oscillatory Ca2+ response in spermatocyte-injected oocytes was due to the actual deficiency of SSF in the spermatocytes rather than to a defective responsiveness of the injected oocytes or to the failure of SSF release into the oocyte cytoplasm. The ability of human round spermatids to induce a response to calcium in oocytes that is similar to that induced by mature spermatozoa may be important for normal embryonic development after spermatid conception.

Combined use of proacrosin immunocytochemistry and autosomal DNA in situ hybridisation for evaluation of human ejaculated germ cells

The recently reported human pregnancies and births after fertilising oocytes with round spermatids recovered from the ejaculate of men with non-obstructive azoospermia have underscored the need for a more accurate evaluation of the nuclear and cytoplasmic maturation status of ejaculated germ cells. In this study we describe our first experience with a method combining the immunocytochemical visualisation of proacrosin with autosomal DNA fluorescence in situ hybridisation (FISH) to assess ejaculated germ cells from patients with a spermiogenesis defect. The proacrosin immunoreactivity, analysed with the use of the monoclonal antibody 4D4, has been detected in cells of round spermatid size presenting a haploid FISH figure as well as in larger cells whose ploidy corresponds to primary and secondary spermatocytes. These observations are in agreement with previously published results obtained, with the use of the same antibody, by immunocytochemical analysis of histological sections of testicular tissue. All the cells of round spermatid size possessing proacrosin immunoreactivity were found to be haploid by FISH. On the other hand, some of the haploid cells of round spermatid size did not possess proacrosin immunoreactivity. The structural pattern of proacrosin immunoreactivity was highly variable both in spermatids and in younger spermatogenic cells. These data show that cell size is the main criterion to be used for the identification of ejaculated round spermatids, whereas the presence of the developing acrosome represents only an auxiliary criterion. The scoring of acrosomal development in ejaculated spermatids may be useful as part of pre-treatment diagnosis before the inclusion of infertile couples in a spermatid conception programme.

Orally effective CVS-1123 prevents coronary artery thrombosis in the conscious dog

BACKGROUND

We examined the oral efficacy of a direct thrombin inhibitor, CVS-1123 [(CH3CH2CH2)(2)-CH-CO-Asp (OCH3)-Pro-Arg-CHO; MW, 575]. The object was to determine whether thrombin inhibition could reduce the incidence of occlusive coronary artery thrombosis in response to arterial wall injury.

METHODS AND RESULTS

Arterial wall injury was induced in conscious dogs by a 150-muA anodal current applied to the intimal surface of the circumflex coronary artery 30 minutes after oral CVS-1123 (20 mg/kg every 8 hours for three doses; n = 11) or placebo containing diluent (n = 10). Dogs were monitored for 8 hours and at 24 hours. The coronary artery remained patent for 24 hours in 8 of 11 CVS-1123-treated dogs. All dogs (n = 10) in the placebo group developed a sustained, occlusive arterial thrombus. Two hours after the initial oral dose, the plasma CVS-1123 concentration was 13 +/- 1 microgram/mL, reaching a maximum of 15 +/- 1 micrograms/mL after the second dose and 4.4 +/- 0.5 micrograms/mL at 24 hours. Ex vivo platelet aggregation to gamma-thrombin was inhibited and activated partial thromboplastin time was increased after treatment with CVS-1123 (P < .05).

CONCLUSIONS

The direct thrombin inhibitor CVS-1123 is effective after oral administration in reducing the incidence of primary thrombus formation in an experimental model of arterial wall injury. Thrombin-specific inhibitors, such as CVS-1123, may be alternative antithrombotic agents in clinical settings in which heparin-associated thrombosis is a complicating factor or when long-term anticoagulation is required.

Effects of protein kinase C activation and inhibition on sperm-, thimerosal-, and ryanodine-induced calcium responses of human oocytes

Previous data have shown that protein kinase C (PKC) participates in the mechanism of sperm-induced calcium oscillations in mammalian oocytes, but the actual role of this enzyme in the oscillation mechanism is still unknown. In this study we show that drugs modulating PKC activity disturb the oscillations induced by spermatozoa, thimerosal and ryanodine, but in a different way for each of the three oscillogenic agents. Moreover, PKC inhibition interferes with the return of the intracellular free calcium concentration to basal values during the sperm- and ryanodine-induced calcium oscillations, but not during the thimerosal-induced calcium oscillations. When the PKC-modulating drugs were applied before any of the three oscillogens, the subsequent calcium oscillations were also disturbed. However, the first calcium spike induced by spermatozoa and thimerosal was little influenced by PKC activation or inhibition. On the other hand, ryanodine failed to produce any calcium response when the PKC activity was clamped to a high level. These data suggest that sustained high PKC activities impede calcium oscillations by interfering with the opening of the ryanodine-sensitive calcium release channel, whereas sustained low activities of the enzyme paralyse the channel in the open state.

Single cell analysis of tyrosine kinase dependent and independent Ca2+ fluxes in progesterone induced acrosome reaction

In this study we developed a single cell analysis protocol with which protein tyrosine kinase (PTK)-dependent and independent Ca2+ fluxes occurring in human spermatozoa in response to progesterone were evaluated. By recording the fluorescence emitted by fluo-3-loaded spermatozoa using a confocal laser scanning microscopy system it was possible not only to monitor relative changes in the intracellular free Ca2+ concentration ([Ca2+]i) but also to determine the time at which the acrosomal exocytosis began. The addition of progesterone produced a rapid transient [Ca2+]i increase in 35% of spermatozoa. In approximately 10% of spermatozoa, this initial [Ca2+]i increase was followed by a secondary [Ca2+]i increase beginning 2-10 min after the progesterone addition and leading to the acrosomal exocytosis in most of these spermatozoa. On the other hand, a rapid triggering of exocytosis during the initial [Ca2+]i increase was a relatively infrequent observation. The inhibition of PTK with genistein or herbimycin A did not influence the initial progesterone-induced [Ca2+]i increase but inhibited the secondary [Ca2+]i increase and the ensuing acrosomal exocytosis. The initial PTK-independent Ca2+ response could be induced by progesterone in both non-capacitated and capacitated spermatozoa, whereas the ability to generate the secondary, PTK-dependent response developed during in-vitro capacitation.

Spermatid injection into human oocytes. I. Laboratory techniques and special features of zygote development

Spermatid injection into the oocyte cytoplasm has been shown recently to yield viable human embryos developing to term after transfer to the mother. This study provides details of the laboratory techniques related to round spermatid injection (ROSI) and elongated spermatid injection (ELSI) and focuses on some special features of zygote development associated with the use of these types of sperm precursor cells for fertilization. A spermatid-enriched fraction was obtained by centrifugation of cells from azoospermic ejaculates through a discontinuous Percoll gradient column. Individual round or elongated spermatids were identified in this fraction and injected deep into oocytes. Oocyte activation was boosted by a vigorous aspiration of the ooplasm at the time of injection. The fertilization rates after ROSI and ELSI were 45 and 44% respectively. A single large syngamy nucleus was detected in 36% of the zygotes that previously showed two normal-sized pronuclei. This condition did not appear to delay the first cleavage division. These observations underscore the importance of distinguishing the syngamy nucleus of diploid zygotes from the female pronucleus of haploid, parthenogenetically activated eggs.

A randomized trial of amphotericin B alone or in combination with itraconazole in the treatment of mucocutaneous leishmaniasis

A randomized trial of amphotericin B (AB) alone and in combination with oral itraconazole (IZ) is carried out in two groups of 10 mucocutaneous leishmaniasis patients from Bolivia and Peru. AB+IZ combination is no better than AB monotherapy, as far as efficacy and tolerability are concerned. No antagonism was detected.

Sperm-induced calcium oscillations of human oocytes show distinct features in oocyte center and periphery

Temporal and spatial characteristics of explosive periodic increases (spikes) of intracellular free Ca2+ concentration ([Ca2+]i) induced by sperm in human oocytes (Ca2+ oscillations) were analyzed by confocal laser scanning microscopy and compared to Ca2+ oscillations induced in oocytes by the thiol reagent thimerosal. During the steady-state period of sperm-induced Ca2+ oscillations, each individual [Ca2+]i spike invariably began from a focus in oocyte periphery and spread throughout the entire peripheral region before propagating to the central ooplasm. This peripheral Ca2+ wave was immediately followed by an explosive [Ca2+]i increase in the central ooplasm. However, this central [Ca2+]i rise only peaked when [Ca2+]i in the peripheral ooplasm was already on the decline. Moreover, the peak [Ca2+]i values were always considerably higher in the oocyte center than in the periphery. In contrast, thimerosal-induced Ca2+ oscillations did not show this particular form of propagation. These data show that sperm-induced Ca2+ oscillations have a unique pattern of spatial dynamics and suggest that the bulk of Ca2+ mobilized during each spike is released from stores that have a relatively high threshold for Ca(2+)-induced Ca2+ release (CICR). These stores are poorly developed, if not absent, in the oocyte cortex, and CICR from them is triggered by previous CICR from another type of store with a lower threshold that are preferentially located in the oocyte cortex and act as a detonator.

Nongenomic steroid action: independent targeting of a plasma membrane calcium channel and a tyrosine kinase

It is known that steroids can produce nongenomic effects on cells, such as opening of ionic channels, membrane receptor aggregation or changes in protein phosphorylation status. However, it is not known whether these different effects, when occurring concomitantly, are linked by a causal relationship or whether they are triggered independently by the steroid ligand. Here we show that progesterone opens a plasma membrane Ca2+ channel and activates a protein tyrosine kinase of human spermatozoa independently of each other because, on the one hand, tyrosine kinase inhibition does not affect the progesterone-induced Ca2+ influx and, on the other hand, the absence of extracellular Ca2+ does not preclude tyrosine-kinase-mediated progesterone-induced acrosomal exocytosis. These data suggest that steroids interact with multireceptor systems on the surface of responsive cells.

Nongenomic effects of 17 beta-estradiol on maturing human oocytes: relationship to oocyte developmental potential

There is increasing evidence for nongenomic steroid effects in various cell types. This study is the first to demonstrate that 17 beta-estradiol (E2) exerts a direct nongenomic effect on maturing human oocytes by inducing a series of transient increases in the intracellular free calcium concentration ([Ca2+]i). This effect of E2 appeared to be specific and was mediated by steroid action on the cell surface. The first of the E2-induced [Ca2+]i increases was induced by an influx of extracellular Ca2+ ions. However, the release of Ca2+ from intracellular stores contributed more significantly to [Ca2+]i waves characterizing the subsequent series of secondary [Ca2+]i increases, although the presence of extracellular Ca2+ still was an absolute requirement for these [Ca2+]i oscillations. The addition of E2 to oocyte maturation medium did not produce any apparent effects on either germinal vesicle breakdown or further progression of meiosis, but it did increase the fertilization and cleavage rates of the in vitro matured oocytes. These findings show that E2 can directly influence the quality of maturing oocytes. This effect is due to steroid action on the cell surface, implies Ca2+ as a second messenger, and contributes to oocyte capacitation for fertilization and early postfertilization development.

Alleviation of acrosome reaction prematurity by sperm treatment with egg yolk

OBJECTIVE

To examine the effects of egg yolk on the spontaneous and ionophore-induced acrosome reaction (AR) and sperm-zona pellucida (ZP) binding in spermatozoa from patients with AR prematurity.

DESIGN

Prospective analysis.

SETTING

Private hospital, public research center, and a university-based laboratory.

PATIENTS

In vitro fertilization patients selected on the basis of previous AR testing.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Frequency of the AR, number of ZP-bound spermatozoa.

RESULTS

The pretreatment of spermatozoa with egg yolk decreased the frequency of AR occurring spontaneously during subsequent sperm incubation in capacitating medium but did not modify the sperm response to ionophore. The egg yolk-treated spermatozoa also showed a greater capacity of binding the ZP than their untreated counterparts.

CONCLUSIONS

The pretreatment of spermatozoa with egg yolk alleviates the sperm-ZP binding deficiency resulting from premature initiation of the AR and may be helpful in IVF with patients showing this anomaly.

[Increase of conjugated bilirubin in diabetics]

Three hundred patients were studied: 150 had NIDDM and the other 150 were non diabetics. Serum glucose and total and fractionated bilirrubin were measured in samples taken after night fasting. The mean glucose in the NIDDM group was 180.4 +/- 17.9 mg/dL (+/- SD) and 82.7 +/- 4.4 mg/dL in the non diabetic (p < 0.001). The levels of total bilirrubin were similar in both groups (0.84 +/- 0.04 vs 0.81 +/- 0.02 mg/dL, p > 0.40) but there were group differences in direct bilirrubin (NIDDM 0.52 +/- 0.03 vs 0.20 +/- 0.01 mg/dL, p < 0.001) and in indirect bilirrubin (NIDDM 0.32 +/- 0.03 vs 0.61 +/- 0.02 mg/dL, p < 0.001). Thus, 62% of the circulating bilirrubin was conjugated in the diabetics and only 25% in the non diabetics. We believe that at least part of the UDP-glucose pathway is altered in NIDDM and leads to an increase in the levels of glucouronic acid and, in turn, may cause a rise in direct bilirrubin at the expense of indirect bilirrubin.

Most living acrosome-reacted spermatozoa do not fuse with the oocyte when inserted into the perivitelline space

OBJECTIVE

To evaluate the frequency with which acrosome-reacted spermatozoa fuse with the oocyte after subzonal insemination (SUZI).

DESIGN

The acrosome reaction frequency determined in sperm suspensions used for SUZI was related with the frequency of sperm-oocyte fusion after the microinsemination procedure. In some experiments, the acrosome reaction frequency was compared in sperm suspensions aspirated into the microinjection needle and in those leaving the needle.

SETTING

Private hospital, public research center, and university-based laboratory.

PATIENTS, PARTICIPANTS

Patients involved in a program of micromanipulation-assisted fertilization and healthy sperm donors.

INTERVENTIONS

IVF-ET.

MAIN OUTCOME MEASURES

Frequency of the acrosome reaction, frequency of sperm-oocyte fusion.

RESULTS

The procedure of sperm aspiration to the microinjection needle followed by active swim-out of motile spermatozoa did not change the overall percentage of acrosome-reacted spermatozoa even though the subpopulation of acrosome-reacted spermatozoa leaving the needle was enriched in recently reacted cells. The frequency of sperm-oocyte fusion was considerably lower than the frequency of the acrosome reaction in both patient and donor sperm samples, irrespective of the number of spermatozoa inserted per egg.

CONCLUSIONS

A spontaneous acrosome reaction does not necessarily predispose a spermatozoon to fuse with the oocyte after SUZI. It remains to be elucidated whether this relative inefficiency of acrosome-reacted spermatozoa is related to technical aspects of SUZI or whether, in a more general sense, the acrosomal exocytosis and the development of sperm-oocyte fusion capacity are distinctly regulated, though closely related, phenomena.