Surgery for endometriosis-associated infertility: do we exaggerate the magnitude of effect?

OBJECTIVE: Surgery remains the mainstay in the diagnosis and management of endometriosis. The number of surgeries performed for endometriosis worldwide is ever increasing, however do we have evidence for improvement of infertility after the surgery and do we exaggerate the magnitude of effect of surgery when we counsel our patients? The management of patients who failed the surgery could be by repeat surgery or assisted reproduction. What evidence do we have for patients who fail assisted reproduction and what is their best chance for achieving pregnancy? MATERIAL AND METHODS: In this study we reviewed the evidence-based practice pertaining to the outcome of surgery assisted infertility associated with endometriosis. Manuscripts published in PubMed and Science Direct as well as the bibliography cited in these articles were reviewed. Patients with peritoneal endometriosis with mild and severe disease were addressed separately. Patients who failed the primary surgery and managed by repeat or assisted reproduction technology were also evaluated. Patients who failed assisted reproduction and managed by surgery were also studied to determine of the best course of action. RESULTS: In patients with minimal and mild pelvic endometriosis, excision or ablation of the peritoneal endometriosis increases the pregnancy rate. In women with severe endometriosis, controlled trials suggested an improvement of pregnancy rate. In women with ovarian endometrioma 4 cm or larger ovarian cystectomy increases the pregnancy rate, decreases the recurrence rate, but is associated with decrease in ovarian reserve. In patients who have failed the primary surgery, assisted reproduction appears to be significantly more effective than repeat surgery. In patients who failed assisted reproduction, the management remains to be extremely controversial. Surgery in expert hands might result in significant improvement in pregnancy rate. CONCLUSION: In women with minimal and mild endometriosis, surgical excision or ablation of endometriosis is recommended as first line with doubling the pregnancy rate. In patients with moderate and severe endometriosis surgical excision also is recommended as first line. In patients who failed to conceive spontaneously after surgery, assisted reproduction is more effective than repeat surgery. Following surgery, the ovarian reserve may be reduced as determined by Anti Mullerian Hormone. The antral follicle count is not significantly reduced. In women with large endometriomas > 4 cm the ovarian endometrioma should be removed. In women who have failed assisted reproduction, further management remains controversial in the present time.

Combination of multiple microsatellite data sets to investigate genetic diversity and admixture of domestic cattle.

Microsatellite markers are commonly used for population genetic analyses of livestock. However, up to now, combinations of microsatellite data sets or comparison of population genetic parameters from different studies and breeds has proven difficult. Often different genotyping methods have been employed, preventing standardization of microsatellite allele calling. In other cases different sets of markers have been genotyped, providing differing estimates of population genetic parameters. Here, we address these issues and illustrate a general two-step regression approach in cattle using three different sets of microsatellite data, to combine population genetics estimates of diversity and admixture. This regression-based method is independent of the loci genotyped but requires common breeds in the data sets. We show that combining microsatellite data sets can provide new insights on the origin and geographical distribution of genetic diversity and admixture in cattle, which will facilitate global management of this livestock species.

Differentiating Dracunculus medinensis from D. insignis, by the sequence analysis of the 18S rRNA gene.

This study, undertaken as a component of the global Dracunculiasis Eradication Program (DEP), was designed to provide molecular tools to distinguish Dracunculus medinensis, the nematode causing human dracunculiasis, from other tissue-dwelling nematodes, including other Dracunculus species that infect humans and other animals. DNA was extracted from D. medinensis and from a closely related species that infects North American carnivores, D. insignis, so that the genes coding for the small-subunit ribosomal RNA (18S rRNA) of the parasites could be amplified, sequenced and compared. Sequences were obtained for 20 specimens of D. medinensis (from humans in Pakistan, Yemen and six African countries endemic for dracunculiasis) and three of D. insignis (from raccoons trapped in the state of Georgia in the southern U.S.A.). All of the D. medinensis 18S-rRNA sequences were found to be 1819 bases long and identical. The three D. insignis 18S-rRNA sequences were also found to be identical to each other but were 1821 bases long and differed from the D. medinensis 18S- rRNA sequence at eight positions (representing a difference of 0.44%). The 18S-rRNA coding region of a Guinea worm extracted from a dog in Ghana was indistinguishable from that of the D. medinensis isolates from human cases. These results provide the basis for the molecular differentiation of D. medinensis that will permit the DEP to determine, rapidly and accurately, whether a worm recovered from an area considered dracunculiasis-free is a specimen of D. medinensis or not.

Admixture and diversity in West African cattle populations.

We present a population genetic analysis of microsatellite variation in 16 West African cattle populations. West Africa represents a unique juxtaposition of different climatic and ecological zones in a relatively small geographical area. While more humid coastal regions are inhabited by the tsetse fly, a vector which spreads trypanosomiasis among cattle, the disease is not transmitted in the drier areas outside this zone. This is the most thorough study of genetic diversity in cattle within this area, which contains genetically important trypanotolerant Bos taurus breeds. Genetic relationships among the many breeds are examined and levels of diversity are assessed. Admixture levels were determined using a variety of methods. Ancestry informative or population-associated alleles (PAAs) were selected using populations from India, the Near East and Europe. Multivariate analysis, the admix program and model-based Bayesian admixture analysis approaches were also employed. These analyses reveal the direct impact of ecological factors and the profound effect of admixture on the cattle of this region. They also highlight the importance of efforts to prevent further dilution of African taurine breeds by B. indicus cattle.

The use of reference strand-mediated conformational analysis for the study of cheetah (Acinonyx jubatus) feline leucocyte antigen class II DRB polymorphisms.

There is now considerable evidence to suggest the cheetah (Acinonyx jubatus) has limited genetic diversity. However, the extent of this and its significance to the fitness of the cheetah population, both in the wild and captivity, is the subject of some debate. This reflects the difficulty associated with establishing a direct link between low variability at biologically significant loci and deleterious aspects of phenotype in this, and other, species. Attempts to study one such region, the feline leucocyte antigen (FLA), are hampered by a general reliance on cloning and sequencing which is expensive, labour-intensive, subject to PCR artefact and always likely to underestimate true variability. In this study we have applied reference strand-mediated conformational analysis (RSCA) to determine the FLA-DRB phenotypes of 25 cheetahs. This technique was rapid, repeatable and less prone to polymerase chain reaction (PCR)-induced sequence artefacts associated with cloning. Individual cheetahs were shown to have up to three FLA-DRB genes. A total of five alleles were identified (DRB*ha14-17 and DRB*gd01) distributed among four genotypes. Fifteen cheetahs were DRB*ha14/ha15/ha16/ha17, three were DRB*ha15/ha16/ha17, six were DRB*ha14/ha16/ha17 and one was DRB*ha14/ha15/ha16/ha17/gd01. Sequence analysis of DRB*gd01 suggested it was a recombinant of DRB*ha16 and DRB*ha17. Generation of new alleles is difficult to document, and the clear demonstration of such an event is unusual. This study confirms further the limited genetic variability of the cheetah at a biologically significant region. RSCA will facilitate large-scale studies that will be needed to correlate genetic diversity at such loci with population fitness in the cheetah and other species.

Admixture analysis of South Asian cattle.

We present population genetic analysis of microsatellite variation in seven Bos indicus cattle breeds from a variety of locations in South Asia. This is the first such study focusing within this area, which is one of the postulated centres of origin of domestic cattle. An estimate of the influence of Bos taurus ancestry was carried out using three approaches: by the systematic selection of population-associated alleles for B. taurus and examination of their frequency; by examining the truncation of genetic distances from European populations; and by a model-based Bayesian admixture analysis. These analyses revealed a B. taurus influence in the Indian subcontinent; part of a gradation which stretches from Europe through the Near East towards Indian and which may be of ancient origin.

Sequence variation in the mitochondrial DNA control region of wild African cheetahs (Acinonyx jubatus).

Five hundred and twenty-five bp of mitochondrial control region were sequenced and analysed for 20 Acinonyx jubatus and one Felis catus. These sequences were compared with published sequences from another domestic cat, 20 ocelots (Leopardus pardalus) and 11 margays (Leopardus weidii). The intraspecific population divergence in cheetahs was found to be less than in the other cats. However variation was present and distinct groups of cheetahs were discernible. The 80 bp RS2 repetitive sequence motif previously described in other felids was found in four copies in cheetah. The repeat units probably have the ability to form secondary structure and may have some function in the regulation of control region replication. The two central repeat units in cheetah show homogenization that may have arisen by convergent evolution.

A community-based trial for the control of lymphatic filariasis and iodine deficiency using salt fortified with diethylcarbamazine and iodine.

To evaluate the effectiveness of salt fortified with diethylcarbamazine (DEC) and iodine for elimination of Bancroftian filariasis and iodine deficiency, all consenting residents of Miton, Haiti (n = 1,932) were given salt fortified with 0.25% diethylcarbamazine and 25 ppm of iodine for one year. Wuchereria bancrofti microfilaria prevalence and intensity, antigenemia, and urinary iodine were measured before and one year after salt distribution began. To measure the effect of DEC-fortified salt on adult worm motility, 15 microfilaria-positive men were examined by ultrasound of the scrotal area. Entomologic surveys were conducted to determine the proportion of W. bancrofti-infected Culex quinquefasciatus. After one year of treatment, the prevalence and intensity of microfilaremia were both reduced by more than 95%, while antigenemia levels were reduced by 60%. The motility of adult worms, as detected by ultrasound, was decreased, but not significantly, by DEC-fortified salt. The proportion of vector mosquitoes carrying infective stage larvae decreased significantly from 2.3% in the nine months before the intervention to 0.2% in the last three-month follow-up period. Iodine deficiency, which had been moderate to severe, was eliminated after one year of iodized salt consumption. The DEC-fortified salt was well accepted by the community and reduced microfilaremia and transmission to low levels in the absence of reported side effects. Based on these results, salt cofortified with DEC and iodine should be considered as a concurrent intervention for lymphatic filariasis and iodine deficiency elimination programs.

Genetic variation in Pneumocystis carinii isolates from different geographic regions: implications for transmission.

To study transmission patterns of Pneumocystis carinii pneumonia (PCP) in persons with AIDS, we evaluated P. carinii isolates from patients in five U.S. cities for variation at two independent genetic loci, the mitochondrial large subunit rRNA and dihydropteroate synthase. Fourteen unique multilocus genotypes were observed in 191 isolates that were examined at both loci. Mixed infections, accounting for 17.8% of cases, were associated with primary PCP. Genotype frequency distribution patterns varied by patients' place of diagnosis but not by place of birth. Genetic variation at the two loci suggests three probable characteristics of transmission: that most cases of PCP do not result from infections acquired early in life, that infections are actively acquired from a relatively common source (humans or the environment), and that humans, while not necessarily involved in direct infection of other humans, are nevertheless important in the transmission cycle of P. carinii f. sp. hominis.

Survey for Cyclospora cayetanensis in domestic animals in an endemic area in Haiti.

From January 1997 through July 1998, we examined stool samples from 327 domestic animals, including pigs, cattle, horses, goats, dogs, cats, guinea pigs, chicken, ducks, turkeys, and pigeons in Leogane, Haiti, for the presence of Cyclospora cayetanensis infection. No coccidian oocysts morphologically compatible with C. cayetanensis were detected in any of the animal samples, despite their living in, or near, households with infected individuals. These results suggest that domestic animals are not reservoir hosts for C. cayetanensis and that in this endemic area, humans are the only natural host for this parasite.

Cyclospora cayetanensis infections in Haiti: a common occurrence in the absence of watery diarrhea.

Stool samples from a population-based cohort of mothers and children living in Leogane, Haiti were tested for Cyclospora cayetanensis from January 1997 through January 1998. Data on gastrointestinal symptoms were also collected. During the winter months of January to March, the infection was detected in 15-20% of the persons sampled. Most infections did not appear to be causing diarrhea and most infected persons had few oocysts detectable in concentrates of stool. The infection appears to have marked seasonality, with highest rates during the driest and coolest time of the year. It may be that in this tropical setting, high summer temperature is the critical environmental factor that influences the seasonality of infection. This study demonstrates that Cyclospora infections in Haiti are common in the general population.

Genetic polymorphism among Cryptosporidium parvum isolates: evidence of two distinct human transmission cycles.

We report the results of molecular analysis of 39 isolates of Cryptosporidium parvum from human and bovine sources in nine human outbreaks and from bovine sources from a wide geographic distribution. All 39 isolates could be divided into either of two genotypes, on the basis of genetic polymorphism observed at the thrombospondin-related adhesion protein (TRAP-C2) locus. Genotype 1 was observed only in isolates from humans. Genotype 2, however, was seen in calf isolates and in isolates from a subset of human patients who reported direct exposure to infected cattle or consumed items thought to be contaminated with cattle faces. Furthermore, experimental infection studies showed that genotype 2 isolates were infective to mice or calves under routine laboratory conditions, whereas genotype 1 isolates were not. These results support the occurrence of two distinct transmission cycles of C. parvum in humans.

Macrophages are the major target cell for HIV infection in long-term marrow culture and demonstrate dual susceptibility to lymphocytotropic and monocytotropic strains of HIV-1.

Haematological abnormalities are often seen in patients infected with HIV. A number of mechanisms are thought to contribute to this bone marrow suppression, including impaired stromal function and direct infection of progenitor cells. Evidence suggests that both bone marrow progenitor cells and perhaps stromal cells are open to infection by HIV, which raises the possibility that bone marrow stromal cells may serve as a reservoir for HIV. This study investigated the cellular targets and kinetics of in vitro infection of stroma in long-term bone marrow culture (LTBMC) using both mono- and lymphocytotropic strains of HIV-1. p24 ELISA and reverse transcriptase (RT) assay demonstrated that stroma could be infected with HIV and release infectious virions. The target cells for infection were shown to be macrophages by immunohistochemistry (APAAP), dual immunofluorescence staining (using CD68 and p24) and electron microscopy. The data show that it was possible to infect stroma in LTBMC with HIV and that such infection was productive. The main target for infection was bone marrow macrophages. In contrast to peripheral blood derived macrophages, these cells were susceptible to both lymphocytotropic and monocytotropic strains of HIV-1. The data suggests that these bone marrow macrophages may act as a reservoir for HIV, Infection of bone marrow macrophages may affect haemopoiesis either by transmission of HIV infection to developing progenitor cells through direct cell-to-cell contact or by altering the ability of the stroma to support normal development.

Tryptamine enhancement of neurotransmitter release under conditions that normally depress calcium influx.

Neurotransmitter release, resulting in excitatory and inhibitory junction potentials (E- and IJPs) is normally mediated by an influx of calcium ions into nerve terminals following depolarization. At a lobster neuromuscular junction, tryptamine is shown to greatly enhance the amplitude and duration of evoked E- and IJPs in low Ca2+-high Mg2+ media that depress Ca2+ influx. This suggests that in the presence of tryptamine, intracellular Ca2+ sources may support evoked, phasic neurotransmitter release.

Potassium measurements in the extracellular spaces of normal and failing cat myocardium.

After periods of quiescence, papillary muscles and trabeculae from normal and hypertrophied-failing cat hearts were subjected to ionic stress induced by stimulation (drive) at different frequencies. Patterns of change in extracellular potassium concentration were measured using ion-selective microelectrodes and were shown to be significantly different in certain key parameters. In both types of tissue, extracellular potassium activity initially increased from the level in the bathing medium, reached a peak, and then returned toward the original levels. However, the time for this to occur was significantly longer in the hypertrophied-failing muscles than in the normal controls. Also, after more than 5 min of drive, the potassium activity in the extracellular spaces was significantly higher in the hypertrophied-failing tissue than in the normal tissue. The results of these experiments indicate that there may be quantitative differences between normal and hypertrophied-failing cardiac muscles with regard to the regulation of ionic balance.

An ultrastructural morphometric study of the papillary muscle of the right ventricle of the cat.

The papillary muscle of the cat heart's right ventricle has not been studied previously with quantitative ultrastructural techniques despite its wide use for functional studies. This tissue was perfusion-fixed, processed for electron microscopy, and morphometric techniques were used to assess the ultrastructural characteristics of the papillary muscle as well as the working myocardial cells. The results of this study were that 73.5% of the papillary muscle was composed of muscle cells, 9.7% of blood vessels, and the remainder of interstitial connective tissue. In the muscle cell the volume fraction of mitochondria was 17.3%, that of myofibrils was 49.8%, and that of the nucleus was 2.0%. The mitochondria to myofibrils ratio was 0.36 and the surface to volume ratio was 0.309. In a quantitative ultrastructural comparison of perfusion and immersion fixed tissue it was found that significant differences in the volume density of the blood vessel lumen existed between the two groups. In addition, there were significant differences in the volume fraction of mitochondria and nucleus between perfusion-fixed and immersion-fixed muscle cells. A concurrent significant decrease between the two groups was also found for the ratio of mitochondria to myofibrils. The perfusion-fixed tissue can be considered to provide only normal baseline data for the papillary muscle of the right ventricle. These data are important as they can be used in future structure-function studies on normal and pathological heart tissue.

The effects of tryptamine on transmitter release at a lobster neuromuscular junction.

Electrophysiological techniques were employed to characterize the effects of tryptamine at excitatory and inhibitory neuromuscular junctions of the stretcher muscle in the carpopodite of lobster walking limbs. Tryptamine was found to have a concentration dependent, biphasic effect on excitatory junction potential (EJP) amplitude. At concentrations of 0.01-0.5 mM tryptamine increased the amplitude of evoked EJPs, but at higher concentrations (greater than 0.5 mM) the amplitude was decreased by this amine. The high concentrations also decreased the amplitude of inhibitory junction potentials (IJPs) and reduced the frequency of miniature excitatory junction potentials (MEJPs). When a preparation in which the EJPs had been depressed by tryptamine was washed with the control, artificial sea water solution, the EJPs were increased to an amplitude greater than that of the pre-tryptamine control. Current-voltage relationship studies showed that tryptamine did not affect the effective resistance of the muscle fiber membrane. Tryptamine had no effect on the amplitude of excitatory responses evoked by the iontophoretic application of glutamate. Concentrations of tryptamine ranging to 10.0 mM affected neither the conduction velocity in meropodite or that of giant central nervous system (CNS) axons. We conclude that tryptamine affects synaptic transmission pre-synaptically by influencing the transmitter release process. Mass spectrometric analysis showed tryptamine to be an endogenous substance in the lobster; but the concentrations were low in the tissues analyzed. The highest concentration (approximately 0.3 nmol/g wet tissue) was in the subesophageal ganglion. Tryptamine was not detected in the meropodite nerves or carpopodite muscles.

Effect of thyroid hormone on canine cardiac Purkinje fiber transmembrane potential.

The electrophysiological effects of chronic 3,5,3'-triiodo-L-thyronine (T3) administration on cardiac Purkinje fibers were studied using intracellular recording techniques. Adult mongrel dogs receiving T3 injections (1 mg/kg sc) three times daily for 7-12 days demonstrated elevated resting heart rates and serum total T3 content, atrophied thyroid glands, and a small body weight loss when compared with controls. Isolated Purkinje fibers from control and T3-treated animals were superfused with an oxygenated Tyrode solution containing 4 mM K+ at 35 degrees C. Preparations were stimulated externally at 1.0, 2.0, and 3.1 Hz for 2-3 min while measurements of action potentials were made. At 1.0 Hz, action potential duration (APD) of T3-treated Purkinje fibers was significantly (P less than 0.01) greater than controls at both 20% (APD20) and 80% (APD80) of repolarization to the maximum diastolic potential (Emax). The overshoot, plateau height, and Emax were not different. Raising the stimulus frequency to 2.0 and 3.1 Hz produced a slight increase in the overshoot and a rate-dependent shortening of the action potential duration until it resembled controls. APD20 shortened proportionately more than APD80, giving the action potential a triangular appearance. The K+ selectivity of the resting membrane was not affected as evidenced by Nernst plots, which were identical in normal and T3-treated fibers. These results demonstrate that thyroid hormone influences the action potential of isolated cardiac Purkinje fibers.

Oximes: 'enzymatic' slow channel antagonists in canine cardiac purkinje fibers?

In mammalian cardiac muscle voltage-dependent activation of slow channels, e.g., the slow inward current channel, may be possible only when the channels are phosphorylated. We examined the electrophysiological actions of oximes, mile nucleophilic agents which show 'phosphatase-like' activity in isolated enzyme systems, to assess their actions on slow channels in cardiac Purkinje fibers. Diacetyl monoxime (DAM) and pyridine-2-aldoxime (NorPAM) produced a marked, reversible and concentration-dependent reduction in the action potential (AP) plateau duration and abolished spontaneous phase 4 depolarization, but produced only minimal effects on resting potential, dV/dt max, action potential amplitude, duration of phase 3, or membrane resistance. Slow response action potentials evoked in the presence of elevated potassium plus isoproterenol or in Na-free solution were abolished by DAM. The effects of DAM on the AP plateau were antagonized by epinephrine, but an increase in Ca was relatively ineffective. The results suggest that oximes may act as surrogate phosphatases to remove phosphate groups which regulate the availability of slow current channels for voltage-dependent activation.

Resting potential changes associated with Na-K pump in failing heart muscle.

Microelectrode and single sucrose gap techniques were used to measure transmembrane potentials in normal and failing papillary muscles. Six muscles from control animals and 10 from banded animals were cooled (2-4 degrees C) and subsequently rewarmed to 37 degrees C. Normal muscles demonstrated significantly greater increases in maximum diastolic potential (--Emax) on rewarming than those from failing animals. In muscles subjected to transient periods of rapid stimulation, --Emax depolarized initially on stimulation but eventually plateaued at a depolarized level and then hyperpolarized beyond prestimulation levels. These changes in --Emax were altered in failing muscles. The initial rate of depolarization (delta -- Emax/delta t) on stimulation and the magnitude of this depolarization (delta -- Emax) was decreased at all rates studied. The time necessary to arrive at the plateau (time to delta -- Emax) was significantly lengthened in failing muscles. The hyperpolarization seen on rewarming cooled preparations and the changes in --Emax during stimulation have both been related to an activation of an electrogenic Na-K pump suggesting that this ion-transport system is altered in failing heart muscle. The decrease in delta -- Emax/delta t and delta -- Emax seen in failing muscles indicates that K efflux may be lower or that the volume of confined intercellular spaces is greater in failing heart muscle.