Biomedical subjects

J R Tichenor

Publications and source records attributed to J R Tichenor.

4 recordsLinked to original sources

PubMed1995

Decay-accelerating factor protects human trophoblast from complement-mediated attack.

Approximately one-fifth of first trimester losses can be characterized by the onset of hypocomplementemia prior to ultrasonographic loss of embryonic viability. Monoclonal antibodies to the membrane complement regulatory protein, decay-accelerating factor (DAF), were bound to the surface of trophoblastic tissues, with the estimated number of DAF molecules in tissues obtained from hypocomplementemic women less than those from normocomplementemic women (approximately 10%). While trophoblastic tissue obtained from normocomplementemic women did not decomplement normal human sera, pretreatment of this tissue with anti-DAF antibodies resulted in activation of the complement (C') system via the alternate C' pathway (ACP). If trophoblastic tissue from normocomplementemic women was pretreated with phospholipase C, decomplementation of human serum occurred. These data strongly suggest that trophoblasts evade the ACP with functional DAF, possibly through absorption of the molecule's lipophilic diacylglycerol membrane-anchored moiety into the outer lipid bilayer of the trophoblast and may be a rational means for the utilization of immunotherapy in recurrent spontaneous aborters.

Abortion, Habitual↗

PubMed1995

Activation of complement in humans with a first-trimester pregnancy loss.

Serum complement (C') activity in recurrent spontaneous aborters and primiparous controls with successful and unsuccessful pregnancies was quantified so as to define the dynamics of C' activation in early pregnancy loss. C' hemolytic activity was shown to be stable throughout the first trimester of pregnancy and did not differ from preconception levels in all of the successful pregnancies of recurrent aborters and controls and in the majority of pregnancy losses. However, 30% of recurrent aborters and 20% of controls with a pregnancy loss demonstrated activation of C' by the alternate pathway as early as the 7th week with a progressive decline in C' activity until abortion was clinically completed. Circulating levels of C3 dropped from 1.34 to 0.53 mg/dl, and factor B levels declined from 0.34 to 0.14 mg/dl in these hypocomplementemic women. Pregnancy loss is therefore associated with C' activation in a subset of both recurrent and nonrecurrent aborters and this occurs largely before loss of fetal viability.

Abortion, Habitual↗

PubMed1995

Ultrasonographic characteristics of first-trimester gestations in recurrent spontaneous aborters.

OBJECTIVE: To compile, for the first time, serial ultrasonographic findings during the first trimester of pregnancy in women with a history of primary recurrent spontaneous abortion so as to define the dynamics of early normal and abnormal gestations in this category of gravidas. STUDY DESIGN: Transvaginal ultrasonograms were obtained weekly from 5 to 12 weeks' gestational age in 40 women, 10 each of four groups: recurrent spontaneous aborters and primiparas (controls), with both successful and failed gestations. RESULTS: Embryonic heart motion was detected in 40-50% of successful pregnancies during the fifth week of gestation and in the balance by the sixth week, while heart motion was detected in no more than 50% of pregnancies that later failed. Of the failed pregnancies, all were evident by the eighth week of gestation, including those with previously documented viability. The gestational sac size and crown-rump length were smaller than expected in both failed groups, with the sac size difference evident as early as week 5 and the crown-rump length difference apparent by week 7. CONCLUSION: Appropriate timing of the initial ultrasonogram in recurrent aborters (i.e., 8 weeks' gestational age) can identify, by means of heart motion and gestational sac features, all pregnancies that will ultimately fail.

Abortion, Habitual↗

PubMed1994

Risk of eye splash in obstetric procedures.

A prospective cross-sectional study was designed to determine the rates of upper facial splash during obstetric deliveries. Macroscopic splashes on the attached eye shields of surgical masks, worn for obstetric deliveries were enumerated for a sample of parturients during a 3-month period. Masks were collected for 68 vaginal and 44 cesarean deliveries, 31% of all deliveries during the study period. For cesarean deliveries, 68% (30) of all masks worn by primary surgeons had at least one splash; 57% (17) of which were heavily contaminated (more than five splashes). For the first assistant, 68% (30) of all masks had at least one splash; 23% (7) of which were heavily contaminated. During vaginal deliveries 44% (30) of masks worn by the delivering physician had at least one splash; 20% (6) of which were heavily contaminated. The primary surgeon in a cesarean section was 1.6 times as likely to be splashed (P < 0.04) when compared with vaginal deliveries and 4.6 times as likely to be heavily contaminated (P < 0.003). Estimated blood loss and the rate of eye splash were linearly related. Method of delivery was not independently associated with eye splash. These findings suggest that the risk of contamination by splash during obstetric procedures is high, particularly for cesarean deliveries because these deliveries tend to have greater blood losses.

Adult↗