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PubMed2004

Patterns of cell-cell coupling in embryonic spinal cord studied via ballistic delivery of gap-junction-permeable dyes.

Intercellular communication mediated by gap junctions is developmentally regulated in many tissues, including the nervous system. In rodent lumbar spinal cord, extensive gap junctional coupling among motor neurons innervating the same muscle is present at birth but is no longer present 1 week later. Little is known about how this motor-pool-specific coupling arises during embryonic development. To address this question, we developed a novel method of visualizing patterns of cell-cell coupling that can be applied to a wide range of tissues. Gap-junction-permeable dyes adsorbed to metal beads were delivered into individual cells in embryonic cerebral cortex or spinal cord using pressure. Dye diffused off of the bead surface into the cytoplasm, crossed gap junctions, and labeled clusters of coupled cells. For embryonic cerebral cortex, this method revealed patterns of cell-cell coupling similar to those reported with other techniques. In embryonic lumbar spinal cord, cell-cell coupling is widespread in the ventricular zone at E11, and the extent of coupling decreases until birth. In the ventral horn, motor neurons are coupled into clusters at E14, with little change in the extent of coupling at E16, and a similar extent of coupling is present at birth. The cell types within clusters, identified by using antibodies against homeodomain transcription factors, were surprisingly heterogeneous in both the ventricular zone and the motor columns. Taken together, these data suggest that the spatial and temporal patterns of cell-cell coupling are dynamic and that cell-type-specific gap junctional coupling arises gradually during spinal cord development.

Age Factors↗

PubMed1988

Electrical coupling between astrocytes and between oligodendrocytes studied in mammalian cell cultures.

The characteristics of electrical coupling between astrocytes and between oligodendrocytes were analyzed in cell cultures derived from rodent central nervous system. Experiments were carried out by impaling one member of a glial pair with separate voltage recording and current passing electrodes (cell 1) and the other cell, a measured distance from the first, with a voltage-recording electrode (cell 2). Astrocyte pairs within 300 microns of one another were always coupled. The coupling ratio was determined for 23 astrocytic pairs various distances apart, and decreased with distance in a roughly exponential manner. The average coupling ratio of astrocytes within 100 microns of each other was 0.44 +/- 0.32. Oligodendrocytes were less strongly coupled to each other than astrocytes. Even cells immediately adjacent to one another were often uncoupled. Among coupled oligodendrocytes within 100 microns of each other, the average coupling ratio was 0.11 +/- 0.1. Current passage between pairs of astrocytes and pairs of oligodendrocytes was nonrectifying. Application of 0.5 mM BaCl2 or 44.6 mM CsCl (substituted for NaCl) depolarized and increased the input resistance of astrocytes and oligodendrocytes. These ions also increased the coupling ratio in astrocyte pairs and oligodendrocyte pairs; this effect was rapid in onset and completely reversible. Ba++ and Cs+ appear to block resting K+ conductance in glia and probably increase the coupling ratio by increasing the effective length constant of the glial membrane without any direct effect on junctional resistance. In three cases, oligodendrocyte pairs that appear uncoupled in normal solution exhibited coupling in the presence of BaCl2 or CsCl. This suggests that oligodendrocytes may be widely coupled by junctions that provide only weak electrical interaction; such junctions might be important for the exchange of small metabolically active molecules. The strong electrical coupling among astrocytes, in concert with their K+-selective membrane conductance, would provide for an electrical syncytium well designed to transport K+ away from areas of focal extracellular accumulation (i.e., the spatial buffer mechanism), and these cells, more than oligodendrocytes, may provide this function.

Animals↗

PubMed1994

An evaluation of least-squares fits to COSY spectra as a means of estimating proton-proton coupling constants. II. Applications to polypeptides.

A new computational method for simultaneously estimating all the proton-proton coupling constants in a molecule from COSY spectra [Yang, J.-X. and Havel, T.F. (1994) J. Biomol. NMR, 4, 807-826] is applied to experimental data from two polypeptides. The first of these is a cyclic hexapeptide denoted as VDA (-D-Ala1-Phe2-Trp3-Lys(Z)4-Val5-Phe6-), in deuterated DMSO, while the second is a 39-residue protein, called decorsin, in aqueous solution. The effect of different data processing strategies and different initial parameter values on the accuracy of the coupling constants was explored. In the case of VDA, most of the coupling constants did not depend strongly on the initial values chosen for the optimization or on how the data were processed. This, together with our previous experience using simulated data, implies strongly that these values are accurate estimates of the coupling constants. They also differ by an average of only 0.36 Hz from the values of the 14 coupling constants that could be measured independently by established methods. In the case of decorsin, many of the coupling constants exhibited a moderate dependence on their initial values and a strong dependence on how the data were processed. With the most successful data processing strategy, the amide-alpha coupling constants differed by an average of 1.11 Hz from the 21 values that could be measured by established methods, while two thirds of the three-bond coupling constants fell within 1.0 Hz of the ranges obtained by applying the Karplus relation to an independently computed ensemble of distance geometry structures. The averages of the coupling constants over multiple optimizations using random initial values were computed in order to obtain the best possible estimates of the coupling constants. Most clearly incorrect averages can be identified by large standard deviations in the coupling constants or the associated line widths and chemical shifts, and can be explained by strong coupling and/or overlap with the water signal, the diagonal peaks or other cross peaks.

Amino Acid Sequence↗

PubMed1982

Electrotonic and dye coupling in hippocampal CA1 pyramidal cells in vitro.

The presence of electrotonic and dye coupling in region CA1 of the guinea-pig hippocampus was investigated in the in vitro hippocampal slice preparation. No electronic coupling potentials were observed in simultaneous recordings from 101 pairs of pyramidal cells. Also, no electrotonically-coupled short latency depolarizations were observed in more than 75 pyramidal cells in response to antidromic activation of the pyramidal cell population, either in normal bathing medium or in medium with lowered Ca2+ concentration and added Mn2+. When the fluorescent dye Lucifer Yellow was injected into pyramidal cell somas, spread of the dye to other cells (dye coupling) was often observed. Injection of Lucifer Yellow into the dendrites of these neurons resulted in many fewer cases of dye coupling. The failure to find electrophysiological evidence of electrotonic coupling among CA1 pyramidal cells suggests that such coupling is not a functionally important feature of this area of the CNS. The lack of electrophysiological evidence of coupling combined with the observation that the site of Lucifer Yellow injection influences the extent of dye coupling further suggests that at least part of the observed dye coupling may be artifactual. Electrotonic coupling may exist in a small percentage of hippocampal pyramidal cells. However, it is not clear that this small amount of coupling is either necessary or sufficient for the synchronization of neural activity as has been hypothesized to occur during epileptogenesis.

Animals↗

PubMed2005

Dye coupling among satellite glial cells in mammalian dorsal root ganglia.

Dorsal root ganglia (DRG) are key elements in sensory signaling under physiological and pathological conditions. Little is known about electrical coupling among cells in these ganglia. In this study, we injected the fluorescent dye Lucifer yellow (LY) into single cells to examine dye coupling in DRG. We found no dye coupling between neurons or between neurons and their attendant satellite glial cells (SGCs). In mouse DRG, we observed that in 26.2% of the cases SGCs that surround a given neuron were dye coupled. In only 3.2% of the cases SGCs that make envelopes around different neurons were coupled. The data from mouse ganglia were very similar to those from rat and guinea pig DRG. The results obtained by injection of the tracer biocytin were very similar to those observed with LY. The coupling incidence within the envelopes increased 3.1-fold by high extracellular pH (8.0), but coupling between envelopes was not affected. Acidic pH (6.8) reduced the coupling. High extracellular K+ (9.4 mM) increased the coupling 2.4-fold and 4.7-fold within and between envelopes, respectively. Low extracellular Ca2+ (0.5, 1.0 mM) partly reversed the effect of high K+ on coupling. The results showed that SGCs in mammalian sensory ganglia are connected by gap junctions. This coupling is very sensitive to changes in pH, and can therefore be modulated under various physiological and pathological conditions. The dependence of the coupling on extracellular K+ and Ca2+ suggests that the permeability of gap junctions can be altered by physiological and pharmacological stimuli.

Animals↗

PubMed2004

A survey on the importance of lumbar coupling biomechanics in physiotherapy practice.

Knowledge of lumbar coupling biomechanics is foundational in many manual therapy disciplines. 3-D studies of lumbar coupling indicate that coupling direction may not be predictable. The purpose of this study was to investigate physiotherapists' perception of importance of lumbar coupling for validation of manual therapy, necessity in treatment, and perceived direction of lumbar coupling biomechanics. A sample of 369 physiotherapists within the United States volunteered to participate in this study. An ologit regression analysis investigated factors associated with perception of lumbar coupling. A Fleiss Kappa determined the agreement of coupling direction among physiotherapists. The majority of physiotherapists indicated that lumbar coupling biomechanics were important or very important, frequently used during treatment, and necessary for validation of manual therapy. The ologit regressions identified that the importance placed upon lumbar coupling biomechanics is highly related toward therapists' pre-concept of coupling. Kappa values for the five spinal segments were negative indicating worse than chance agreement: L1-2 = -0.10; L2-3 = -0.11; L3-4 = -0.09; L4-5 = -0.10; and L5-S1 = -0.09. The poor Kappa values, strong pre-conceptual perceptions of coupling necessity, and the importance placed upon lumbar coupling for treatment could lead to disparities among physiotherapists in lumbar manual therapy assessment and treatment.

Adult↗

PubMed2001

Artificial electrotonic coupling affects neuronal firing patterns depending upon cellular characteristics.

While there have been numerous theoretical studies indicating that electrotonic coupling via gap junctions interacts with the intrinsic characteristics of the coupled neurons to modify their electrical behaviour, little experimental evidence has been provided in coupled mammalian neurons. Using an artificial electrotonic junction, two distant uncoupled neurons were coupled through the computer, and the coupling conductance was varied. Tonically firing CA1 hippocampal pyramidal neurons reduced their spike firing frequency when coupled to thalamic or pyramidal cells, showing that the electrical coupling can be considered as a low-pass filter. The strength of coupling needed to entrain spike bursts of pyramidal neurons was considerably lower than the coupling needed to synchronize two neurons with different cellular characteristics (thalamic and pyramidal cells). Coupling promoted burst firing in a non-bursting cell if it was coupled to a spontaneously bursting neuron. These results support modelling studies that indicate a role for gap-junctional coupling in the synchronization of neuronal firing and the expression of low-frequency bursting.

Action Potentials↗

PubMed1998

The effect of second-order couple on the application of torque.

Complex combinations of linear forces, moments, and couples are developed by the arch wire during orthodontic treatment. For instance, application of torque to a canine during distal driving may create force interactions if the tooth tips distally toward the extraction site. This investigation studied the effect of second-order couples and bracket angulations on the application of torque to a single tooth. By using a test apparatus to simulate application of torque to a single tooth, 0.016 x 0.022 inch stainless steel wires were tested in longitudinal torsion simultaneous to fixed amounts of second-order couples or fixed degrees of second-order bracket angulation. Application of a second-order couple through a bracket to a longitudinally twisted arch wire produces a third-order couple, since the bracket slot walls exert forces on the wire, tending to detwist it. This third-order couple will usually be small as the distance between the two couple members is short. Nevertheless, it may have a restraining effect on the third-order wire-bracket interaction. The results show that application of second-order couples or bracket angulations lead to an increase in exerted torque for angles of twist below 22 degrees. Because of torsional play, a wire twisted 18 degrees in a 0.018-inch bracket slot did not exert any torque unless it was subjected to a second-order couple. Thus, in an in vivo situation where forces interact, the actual torsional play may be substantially less than predicted from theoretical models only regarding third-order mechanics. The restraining effect of second-order couples tapered when the torque created by longitudinal twisting became much larger than the torque exerted by the second-order couple. Second-order couples of biologically acceptable magnitudes had little effect on the level of torque after the third-order clearance had been eliminated.

Cuspid↗

PubMed1971

Experimental alteration of coupling resistance at an electrotonic synapse.

Adjacent segments of the septate axon of the crayfish Procambarus are electrotonically coupled by junction located in the septa between them (see Pappas et al. 1970. J. Cell Biol.49:173). The coupling resistance at the septa was changed by several experimental treatments. Mechanical injury to an axon increased coupling resistance (more than 7-fold); no recovery of coupling resistance was observed, although the resting potential and resistance of the injured axon could return to near normal levels. Immersion in salines with Na propionate substituted for NaCl increased coupling resistance (mean: 6.1-fold). On return of the preparation to normal saline, coupling resistance recovered virtually completely. Immersion in low Ca(++) solutions moderately increased coupling resistance (3.5-fold or less), but return to normal saline was followed by large increases in coupling resistance (5-100-fold). 60 nM Ca(++) is near the maximum concentration that leads to increased coupling resistance on return to normal saline. Large increases in coupling resistance are associated with separation of junctional membranes (Pappas et al. 1970. Ibid.); calculations show that the separated membranes greatly increase in resistance. Increase in coupling resistance is probably an important response to injury. Mechanisms underlying changes reported here may be relevant to normal physiological processes of coupling and decoupling.

Acetates↗

PubMed1981

Mathematic coupling of data: a common source of error.

The relationship between two variables may be mathematically coupled if either one or both variables are derived and/or calculated, and this can lead to erroneous results and invalid conclusions. The purpose of this report is to identify four types of mathematic coupling of data. Type 1 coupling involves directional changes in two variables which are mathematically coupled. Type 2 coupling is the functional relationship between two calculated variables which have one or more common component variables. Type 3, the most common type of mathematic coupling, is direct algebraic coupling between two variables, when one or more of the variables is derived and/or calculated. Type 4 is indirect coupling or physiologic coupling. The common problem in each type of mathematic coupling is that one variable either directly or indirectly contains the whole or components of the second variable. Statistical techniques, when properly applied to the relationship between the two variables, further obscure the underlying mathematic coupling, and tend to support the erroneous results. Recognition of mathematic coupling is imperative for correct data analysis and accurate interpretation.

Statistics as Topic↗

PubMed2005

Reproductive decisions by couples undergoing artificial insemination with donor sperm for severe male infertility: implications for medical counselling.

Since 1992, ICSI has been introduced as a successful treatment for male infertility, including azoospermia. The present study is aimed at evaluating the practice of insemination with donor sperm (AID) in infertile couples who may benefit from the new developments that ICSI has brought in the last decade. AID was performed in 440 heterosexual couples. Twelve couples were lost for follow-up (3%). In 128 (29.9%) and 229 (53.5%) of the couples the husband was either oligozoospermic (OAT) or azoospermic. In 60 couples (14.0%) the man had a transmissible genetic trait. In 11 couples (2.6%) there were other indications for performing AID. In the OAT group 36 couples never had ICSI treatment (28.1%) because they had already an AID child born before the introduction of ICSI (n = 16), the burden of ICSI treatment was too high (n = 9) or they considered that ICSI success rate was too low (n = 7). Ninety-two couples tried ICSI treatment before opting for AID (71.9%), mainly because ICSI failed (n = 43). In 229 couples the husband had azoospermia (53.5%). In 112 couples (49%) no sperm or too few testicular sperm were found at testicular biopsy (TESE) and 15 couples (6.5%) had more than three failed ICSI-TESE attempts. Eighty-one azoospermic men refused TESE (35.4%) because of an anticipated low success rate (n = 28) or the burden of this approach (n = 23). Although a majority of patients could opt for ICSI, our results show that AID is still an option for many couples for whom these techniques were either not feasible or not successful. A substantial proportion of patients (33%) did not even opt for these advanced fertility treatments.

Counseling↗

PubMed1999

Marital therapy: qualities of couples who fare better or worse in treatment.

To evaluate the effectiveness of couples therapy and determine the characteristics and qualities of couples who fare best in treatment, 139 couples presenting at a nonlaboratory sliding-fee clinic in Dallas, Texas, were evaluated. Observational and self-report measures of the Beavers Systems Model were taken at the first session and, for some subjects, at termination. Therapists also rated the couples on goal attainment and on dimensions of the therapeutic alliance. Not surprisingly, there was a direct association between number of sessions and goal attainment, with couples attending only one or two sessions having the lowest goal attainment. There were also significant family functioning qualities associated with success: more competent couples fared better in therapy. Another consistent finding was that couples with no children did better in treatment than those who were also parents. It is interesting that remarried couples without children did best in treatment, followed by first-married couples with no children, first-married couples with children, and, finally, remarried couples with children. Implications for screening and clinical work with couples are presented.

Adult↗

PubMed2003

Cardioventilatory coupling in resting human subjects.

In 48 conscious resting subjects we examined the temporal coupling of heart beat timing and the onset of inspiration (cardioventilatory coupling), and the relationship between coupling and spectral indices of autonomic function. Using the proportional Shannon entropy (SH(alpha)) of the RI(-1) interval (interval between inspiration and the preceding ECG R wave) as a measure of coupling we detected statistically significant coupling in 32 of the 48 subjects. This was confirmed by visual inspection of time series plots of RI intervals, in which coupling was evident as horizontal banding. Coupling resulted in a significant preference for whole number heart rate/respiratory frequency ratios. The strongest coupling was associated with low ventilatory frequency and high heart rate variability in the high (0.15-0.40 Hz) and low (0.04-0.15 Hz) frequency ranges, but was not related to blood pressure variability, or to a spectral measure of baroreflex sensitivity (alpha-index, low frequency range). There was no difference in coupling strength between males and females. We have previously described cardioventilatory coupling in spontaneously breathing anaesthetised subjects. The current study extends those observations by demonstrating that the qualitative features of coupling seen during anaesthesia are also observed in the conscious state. We conclude that the role of coupling in normal physiological respiratory control needs to be more widely explored.

Adolescent↗

PubMed2004

Electrotonic coupling between stratum oriens interneurones in the intact in vitro mouse juvenile hippocampus.

Using the isolated juvenile (7-14 days) mouse whole hippocampus preparation, which contains intact complex local circuitry, 145 dual whole cell recordings were made from stratum oriens (s.o.) interneurones under infrared microscopy. In 11.7% of paired recordings, evidence for direct electrotonic coupling between the s.o. interneurones was obtained from the response of one interneurone to a long (400-600 ms) constant current pulse passed into the coupled interneurone. When specifically orienting the dual recordings in the transectional plane of the hippocampus, 18.5% of paired recordings showed electrotonic coupling. The coupling coefficient, estimated from averaged data, was 6.9 +/- 4.7%, ranging from 1.3 to 17.6%. The time constant of the electrotonically transmitted hyperpolarization was inversely related to the coupling coefficient between the two neurones. The electrotonic responses of one neurone to constant current pulses injected into the other coupled neurone were intermittent. Spikes in one of the coupled neurones were associated with small electrotonic EPSPs (spikelets) in the other coupled neurone, in those neuronal pairs with coupling coefficients greater than 10%. Failure of spikelet production following a spike in the coupled cell occurred 5-10% of the time. Electrotonic coupling and spikelets persisted in the presence of chemical synaptic transmission blockade by CNQX, APV and bicuculline, or in zero Ca(2+) perfusate, but were abolished by carbenoxolone (100 microm), a gap junctional blocker. These data confirm the existence of electrotonic coupling between s.o. interneurones, presumably via gap junctions located in dendrites.

Action Potentials↗

PubMed1994

Antenatal screening for cystic fibrosis: a trial of the couple model.

OBJECTIVE: To assess the delivery and acceptability of antenatal couple screening for cystic fibrosis. Carrier status was notified only when both members of a partnership had cystic fibrosis alleles and therefore a one in four risk of having an affected child. DESIGN: Mouthwash samples were tested when both partners participated. Results were returned only to positive couples. SETTING: Two large maternity hospitals in Edinburgh. SUBJECTS: Screening was offered to all couples who booked at one of the two hospitals. MAIN OUTCOME MEASURES: (a) The take up of screening, carriers and carrier couples identified, take up of prenatal diagnosis, and numbers of affected fetuses detected; (b) questionnaire measures of patient satisfaction and stress. RESULTS: Screening was offered to 8536 couples. 714 (8.4%) were regarded as ineligible, usually because of late booking or absence of a partner. 1900 (24.3%) of the remainder declined screening. Among the 5922 screened couples, four tested positive--that is, both partners were cystic fibrosis heterozygotes. All four elected to have prenatal diagnosis. There were three terminations of pregnancy because of an affected fetus, one couple having two successive pregnancies with affected fetuses. The participation rate was 76% for eligible couples (5922/7822) and 69% for all couples (5922/8536). Only 89 screened couples (1.5%) requested information on individual carrier status. No anxiety was detected among a cohort of the screened population, and 99% of questioned participants expressed satisfaction with the concept of couple screening. CONCLUSIONS: Antenatal couple screening is a satisfactory and acceptable way of screening for cystic fibrosis and has been adopted as routine in the two trial hospitals.

Anxiety↗

PubMed1991

Relationship between Na+ current expression and cell-cell coupling in astrocytes cultured from rat hippocampus.

1. Cell-cell coupling between hippocampal astrocytes in culture was studied by following the intracellular spread of the low molecular weight fluorescent dye Lucifer yellow (LY). Dye coupling appeared as early as 24 h after plating, at which time approximately 20% of all astrocytes that physically contacted neighboring cells showed dye coupling. 2. The percentage of coupled cells increased with time in culture and peaked after 10 days in vitro (DIV) when approximately 50% of astrocytes showed coupling. Further time in culture, up to 20 DIV, did not increase the percentage of coupled cells. Thus, coupled and noncoupled astrocytes coexist in hippocampal cultures in approximately equal numbers. 3. Na+ currents were expressed in a subpopulation of hippocampal astrocytes and changed characteristics during in vitro development. A "neuronal type" of Na+ current, so called because of an h alpha curve that had a midpoint near -60 mV, was observed within the first 5 days post-plating. A "glial type" of Na+ current, characterized by a -25 mV shift in its h alpha curve, was only expressed after 6 days in culture. 4. Na+ current expression was restricted to hippocampal astrocytes that did not exhibit dye coupling; astrocytes that exhibited dye coupling (n = 39) did not show measurable Na+ currents. 5. The failure to see Na+ currents in coupled astrocytes cannot be explained by insufficient space-clamp since astrocytes acutely uncoupled with octanol (10 microM) did not reveal Na+ current expression. Control experiments showed that low concentrations of octanol (i.e., 10-100 microM) did not block Na+ currents; blockage of Na+ currents by octanol was only observed at high concentrations (e.g., 50-fold the concentration used for uncoupling). These observations support the idea that Na(+)-channel expression was restricted to noncoupled astrocytes. 6. The time courses for the development of cell coupling and Na+ current expression appeared to be inversely correlated and suggested a gradual increase in cell coupling in concert with a loss in Na+ current expression with time in culture.

Animals↗

PubMed1974

Significance of coupling intervals of ventricular extrasystoles.

Extrasystoles may have fixed or variable coupling intervals. The latter may be divided into those with coupling intervals related to and following the T wave of the preceding QRS (approximate coupling) and those which occur throughout electrical diastole with no obvious relationship to the T wave of the dominant rhythm (random coupling). Extrasystoles with random and approximate coupling may or may not be parasystolic. The relationship of extrasystoles to the dominant rhythm may alter. In particular, fixed coupling may precede or alternate with approximate coupling. These groups cannot be considered distinct, in view of transitions from one type of extrasystole to another. Extrasystoles with both approximate coupling and fixed coupling tend to occur just after the T wave and often occurred on the apex of the U wave. Approximate non-parasystolic coupling was infrequent in electrocardiograms which were otherwise normal. Random non-parasystolic coupling and parasystole only occurred in patients with cardiac disease. In view of these findings, it is proposed that extrasystoles should be described by their degree of dependence on each other (regularity of interectopic intervals) and their degree of dependence on conducted beats (regularity of coupling intervals),

Cardiac Complexes, Premature↗

PubMed1982

Chromosome translocations in couples with multiple spontaneous abortions.

The reported incidence of balanced chromosomal translocations in couples with multiple spontaneous abortions (SABs) ranges from 0% of 31%. Because our experience has suggested that SABs are useful for ascertaining balanced translocations, we report the results of chromosome analyses performed on blood specimens from 440 individuals including 200 couples who were ascertained on the basis of two or more SABs. Balanced translocations were found in 3.6% of these 200 couples. For 122 of these couples, more detailed reproductive histories were available. For 48 couples with two SABs, four (8.4%) had balanced translocations; for 37 couples with three SABs, one (2.7%) had a balanced translocation; for 20 couples with four SABs, two (10%) had balanced translocations; and for 17 couples with five or more SABs, one (5.9%) had a balanced translocation. These 122 couples could also be classified on the basis of having abnormal or healthy children. For 40 couples with two or more SABs, one or more healthy children, and no abnormal offspring, two (5.0%) had balanced translocations; for 20 couples with two or more SABs and one or more abnormal children (and in some cases one or more healthy children), one (5.0%) had a balanced translocation; for 62 couples with two or more SABs and no other pregnancies, four (6.5%) had balanced translocations.

Abortion, Habitual↗