Microinjection of mitochondria into zygotes creates a model for studying the inheritance of mitochondrial DNA during preimplantation development.

OBJECTIVE: To determine the effect of mutant mitochondria on preimplantation embryo development and of preimplantation embryo development on the survival of mutant mitochondrial DNA. DESIGN: Laboratory research. SETTING: Academic research laboratory. PATIENT(S): None. INTERVENTION(S): Mutant and wild-type mitochondria, fractionated from tissue obtained from a patient with MELAS syndrome, a mitochondrial disease, were microinjected into mouse zygotes. Control zygotes received either no injection or sham injection. MAIN OUTCOME MEASURE(S): Preimplantation embryo development and survival of mutant mitochondrial DNA as determined by polymerase chain reaction analysis. RESULT(S): After microinjection into zygotes, the MELAS mutation could be identified by polymerase chain reaction until the hatched blastocyst stage of embryo development. The survival of MELAS-injected zygotes, observed for 4 days after injection, did not differ from the survival of zygotes injected with wild-type mitochondria or from the survival of uninjected or sham-injected controls. CONCLUSION(S): It appears that preimplantation embryo development does not screen out mitochondrial DNA mutations introduced into fertilized oocytes, and low levels of mutant mitochondrial DNA do not disrupt early embryo development.

Transmembrane regulation of intracellular calcium by a plasma membrane sodium/calcium exchanger in mouse ova.

Regulation of cytoplasmic free calcium concentration ([Ca2+)]i) is a key factor for maintenance of viability of cells, including oocytes. Indeed, during fertilization of an ovum, [Ca2+]i is known to undergo oscillations, but it is unknown how basal [Ca2+]i or calcium oscillations are regulated. In the present study we investigated the role of the plasma membrane in regulating [Ca2+]i of metaphase II-arrested mouse oocytes (ova). Ova were collected from B6C3F1 mice treated with eCG (10 IU) and hCG (5 IU), and intracellular calcium was determined by means of fura-2. Extracellular calcium flux across the zona pellucida was detected noninvasively by a calcium ion-selective, self-referencing microelectrode that was positioned by a computer-controlled micromanipulator. Under basal conditions ova exhibited a calcium net efflux of 20.6 +/- 5.2 fmol/cm2 per sec (n = 69). Treatment of ova with ethanol (7%) or thapsigargin (25 nM-2.5 microM) transiently increased intracellular calcium and stimulated calcium efflux that paralleled levels of [Ca2+]i. The presence of a Na+/Ca2+ exchanger was indicated by experiments employing both bepridil, an inhibitor of Na+/Ca2+ exchange, and sodium-depleted media. In the presence of bepridil, a net influx of calcium was revealed across the zona pellucida, which was reflected by an increase in the [Ca2+]i. In addition, replenishment of extracellular sodium to ova that had been incubated in sodium-depleted media induced a large calcium efflux, consistent with the actions of Na+/Ca2+ exchange. Sodium/calcium exchange in mouse ova may be an important mechanism that regulates [Ca2+]i.

Telemedicine in vascular surgery: feasibility of digital imaging for remote management of wounds.

PURPOSE: Telemedicine coupled with digital photography could potentially improve the quality of outpatient wound care and decrease medical cost by allowing home care nurses to electronically transmit images of patients' wounds to treating surgeons. To determine the feasibility of this technology, we compared bedside wound examination by onsite surgeons with viewing digital images of wounds by remote surgeons. METHODS: Over 6 weeks, 38 wounds in 24 inpatients were photographed with a Kodak DC50 digital camera (resolution 756 x 504 pixels/in2). Agreements regarding wound description (edema, erythema, cellulitis, necrosis, gangrene, ischemia, and granulation) and wound management (presence of healing problems, need for emergent evaluation, need for antibiotics, and need for hospitalization) were calculated among onsite surgeons and between onsite and remote surgeons. Sensitivity and specificity of remote wound diagnosis compared with bedside examination were calculated. Potential correlates of agreement, level of surgical training, certainty of diagnosis, and wound type were evaluated by multivariate analysis. RESULTS: Agreement between onsite and remote surgeons (66% to 95% for wound description and 64% to 95% for wound management) matched agreement among onsite surgeons (64% to 85% for wound description and 63% to 91% for wound management). Moreover, when onsite agreement was low (i.e., 64% for erythema) agreement between onsite and remote surgeons was similarly low (i.e., 66% for erythema). Sensitivity of remote diagnosis ranged from 78% (gangrene) to 98% (presence of wound healing problem), whereas specificity ranged from 27% (erythema) to 100% (ischemia). Agreement was influenced by wound type (p < 0.01) but not by certainty of diagnosis (p > 0.01) or level of surgical training (p > 0.01). CONCLUSIONS: Wound evaluation on the basis of viewing digital images is comparable with standard wound examination and renders similar diagnoses and treatment in the majority of cases. Digital imaging for remote wound management is feasible and holds significant promise for improving outpatient vascular wound care.

Monocyte chemotactic protein-1 expression in human preovulatory follicles and ovarian cells.

There is a considerable population of macrophages (5-15% of the cells) within the human ovarian follicle at the time of ovulation. Macrophages are also present within the ovarian stroma, mostly near perifollicular capillaries. We hypothesized that macrophage migration in and around the preovulatory follicle is hormonally regulated and that regulation of macrophage migration occurs through local modulation of monocyte chemotactic protein-1 (MCP-1) that chemoattracts and activates monocytes/macrophages. In this regard, we investigated the expression and regulation of MCP-1 in human follicular fluid and in ovarian stromal and granulosa-lutein cell cultures. The concentration of MCP-1 in follicular fluid samples obtained from women prior to the administration of hCG was (n = 4) 90 +/- 27 (mean +/- S.E.) pg/ml; in samples obtained 12 h after the hCG administration it was (n = 3) 135 +/- 23 pg/mL; in follicular fluids obtained 34 h after the hCG administration it was (n = 126) 322 +/- 46 pg/mL (P = 0.007 vs. pre-hCG). The mean ratio of follicular fluid/serum MCP-1 levels was 4.18. There was a correlation between follicular fluid MCP-1 levels and follicular fluid or serum progesterone levels (r = 0.21, P = 0.02; r = 0.29, P = 0.03, respectively). MCP-1 mRNA and the protein were expressed in ovarian stromal and granulosalutein cells in culture and were increased by interleukin-1 alpha and tumor necrosis factor-alpha in a time- and concentration-dependent manner. LH/hCG induced higher levels of MCP-1 mRNA expression and protein production in both cell cultures. We propose that regulation of MCP-1 in ovarian stromal and granulosa-lutein cells by cytokines may play a role in the physiology of periovulatory events.

Modulation of leukemia inhibitory factor gene expression and protein biosynthesis in the human fallopian tube.

OBJECTIVE: The fallopian tube is the site of fertilization and early embryonic growth and a common site of ectopic implantation. Although the factors responsible for early embryogenesis and implantation are incompletely understood, leukemia inhibitory factor may have an important role in early embryonic development and implantation. We set out to evaluate the production and modulation of leukemia inhibitory factor in the fallopian tube. STUDY DESIGN: We first investigated leukemia inhibitory factor messenger ribonucleic acid levels in fallopian tubes. We then investigated leukemia inhibitory factor messenger ribonucleic acid and protein production in tubal epithelial and stromal cell cultures. RESULTS: Leukemia inhibitory factor messenger ribonucleic acid is expressed in the fallopian tube with only slight variation during the menstrual cycle; however, it is markedly elevated in association with ectopic pregnancy. The level is higher in the tubal mucosa than in the remaining layers and is higher in the more distal segments of the fallopian tube. Estradiol and progesterone did not modulate leukemia inhibitory factor expression in epithelial or stromal cell cultures. Interleukin-1 alpha, tumor necrosis factor-alpha, and transforming growth factor-beta enhanced leukemia inhibitory factor expression in epithelial and stromal cells, with transforming growth factor-beta 1 enhancing expression by fourfold in stromal cells. Epithelial cells secreted high levels of leukemia inhibitory factor compared with stromal cells (332 +/- 89 vs 25 +/- 42 pg/mg total protein). Yet stromal cells treated with transforming growth factor-beta alone or in combination with epidermal growth factor and platelet-derived growth factor, as well as TNF-alpha alone or in combination with interleukin-1 alpha enhanced secretion of leukemia inhibitory factor at or above the levels found with epithelial cells. CONCLUSIONS: We speculate that the high constitutive levels of leukemia inhibitory factor expressed in the ampullary portion of the fallopian tube may play a role in early embryonic development. Additionally, elevated expression with ectopic implantation and the marked induction of secretion in the tubal stroma by growth factors and cytokines suggest a link between inflammation, leukemia inhibitory factor, and tubal ectopic pregnancies.

Interleukin-8 expression and modulation in human preovulatory follicles and ovarian cells.

Just before the time of ovulation, the number of neutrophils increases markedly in the thecal layer of the leading follicle. A preovulatory rise in chemotactic activity for neutrophils in human follicular fluid has also been detected. We hypothesized that interleukin-8 (IL-8), a neutrophil chemoattractant/activating factor and a potent angiogenic agent, may be an important modulator of leukocyte chemotaxis in ovulatory function. In this regard we investigated the expression and modulation of IL-8 in human follicular fluid samples from patients undergoing in vitro fertilization-embryo transfer therapy and in ovarian stromal and granulosa-lutein cell cultures. The concentration of IL-8 in pre-hCG follicular fluid samples (n = 4) was 16 +/- 12 (mean +/- SEM) pg/ml, and that in post-hCG samples (n = 101) was 262 +/- 45 pg/ml (P = 0.001). In post-hCG samples, the concentration of IL-8 in an individual follicle correlated with the size of that follicle (r = 0.61; P = 0.02). We also observed a correlation between serum IL-8 levels (22 +/- 3 pg/ml) and follicular fluid levels (303 +/- 143 pg/ml), with a 14-fold gradient (r = 0.71; P = 0.01) in 11 patients tested for both. IL-8 messenger RNA (mRNA) and the protein were expressed constitutively in ovarian stromal cell cultures, and the level was increased by IL-1 alpha and tumor necrosis factor-alpha in a time- and concentration-dependent manner. hCG and LH induced higher levels of IL-8 mRNA expression and protein production. Granulosalutein cells also expressed IL-8 mRNA and protein, and the levels were increased by IL-1 alpha and tumor necrosis factor-alpha. Importantly, progesterone suppressed both basal and IL-1 alpha-stimulated IL-8 expression in stromal and granulosa-lutein cell types. In summary, we found that IL-8 levels are elevated in periovulatory follicular fluid, and both granulosa-lutein and ovarian stromal cells express the mRNA and produce the protein. The modulation of IL-8 in these cell cultures by steroid and trophic hormones suggests that IL-8 may play an important role in the physiology of ovulation, such as timely follicular rupture and neovascularization of the corpus luteum.

Mitochondrial deoxyribonucleic acid deletions in oocytes and reproductive aging in women.

OBJECTIVE: To determine whether oocytes from women harbor deletions in mitochondrial DNA (mtDNA) and whether deleted mtDNA is more common in oocytes from older women than oocytes from younger women. DESIGN: A polymerase chain reaction (PCR)-based strategy, which depends on deletions approximating otherwise widely separated primers to demonstrate mtDNA deletions in individual oocytes, was used. SETTING: Yale In Vitro Fertilization Clinic and Laboratory at Yale University School of Medicine. MAIN OUTCOME MEASURES: Primers flanked a region of the mitochondrial genome in which long direct repeated sequence predispose to deletions. The primers identified the 0.5-kb "common" deletion. Deleted mtDNA was represented by a 0.5-kb band when primers separated by 5 kb were used. Control reactions used primers that amplify mtDNA outside the deletion hotspot. Positive controls included brain and/or muscle from aged individuals, and negative controls included fetal tissue and DNA-free blanks. Nested primers confirmed the specificity of the deleted product. RESULTS: Unfertilized oocytes, muscle, and brain tissue contained PCR products consistent with deleted mtDNA. Fetal tissue lacked the mtDNA deletion product. Deleted mtDNA was detected in single oocytes. Oocytes from older women were more likely to contain deleted mtDNA than oocytes from younger women. CONCLUSION: Deleted mtDNA in unfertilized oocytes may serve as a marker of oocyte senescence.