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Biomedical subjects

C V Smith

Publications and source records attributed to C V Smith.

At least 109 records · Page 6Linked to original sources
PubMed1992

Transvaginal sonography of cervical width and length during pregnancy.

Transvaginal ultrasonography has been proposed as a reliable method of assessing dimensions of the cervix. The purpose of the current investigation was to establish normative data for cervical width and length during pregnancy. This information may be helpful in predicting patients at risk for preterm birth. A transvaginal 5 or 7.5 MHz transducer was used on 132 consecutive low-risk pregnant women undergoing evaluation for gestational dating purposes. Even in cases of patient obesity or an empty bladder, high resolution was possible and permitted cervical measurement in all but one case. The external cervical width at the vaginal fornices was found to increase with advancing gestation (R = 0.512, P < 0.005). The cervical length from internal os to external os was found not to change with advancing gestation (R = 0.11, P = 0.30). Using these normative data, investigation is recommended to determine whether measuring cervical width and length is useful in predicting preterm labor and delivery.

Anthropometry↗
PubMed1992

Patients' acceptance of monitoring fetal movement. A randomized comparison of charting techniques.

An active fetus is reassuring to both the woman and her obstetrician. Numerous techniques of charting fetal movement have been shown to assist the clinician in caring for the high-risk patient. Patients' compliance with daily monitoring is an important clinical issue, and little information exists on the fetal movement record most preferred by the patient. A comparative study evaluated patients' acceptance of three commonly used charts. The 85 enrollees were given the different charts in a random manner and questioned at the next office visit. All the patients expressed approval of the concept and a lack of anxiety about such monitoring, complied with our instructions and returned the completed records. The neonatal outcomes were favorable with all the charting techniques in our antenatal fetal surveillance plan. The "count-to-10" method was rated most preferred in 95.3% of the cases. The reasons cited included convenience and less time needed to complete the recording. The mean time to complete this record was 19.7 +/- 22.9 minutes rather than one or more hours, as with the other charting methods. The results of this randomized investigation show the simple and rapid count-to-10 method to be the most acceptable charting technique to our patients for monitoring fetal movement.

Female↗
PubMed1992

Antepartum fetal surveillance in the preterm fetus.

Over the past two decades, obstetric and neonatal health care has shifted its attention to the preterm pregnancy. Due to the immaturity of the fetal autonomic nervous system, the usual diagnostic criteria for intervention in the preterm fetus are not available. Alternative methods such as the biophysical profile and Doppler offer the clinician a reasonable alternative in identifying potential fetal compromise.

Acoustic Stimulation↗
PubMed1991

Uterine and fetal Doppler flow changes after intravaginal prostaglandin E2 therapy for cervical ripening.

Nineteen patients received prostaglandin E2 as a 2.5 mg gel (seven cases), 3.3 mg chip (five cases), or 10 mg controlled-release pessary (seven cases) for preinduction cervical ripening. Blood flow velocities did not change significantly for the uterine arcuate artery, fetal aorta, and umbilical artery circulations after any of the treatments. In no case did systolic/diastolic ratios consistently elevate above baseline values.

Blood Circulation↗
PubMed1991

Patterns of uterine activity after intravaginal prostaglandin E2 during preinduction cervical ripening.

In a randomized study, uterine activity patterns were characterized with a portable pressure-sensitive device in 40 nonlaboring women at term with an unfavorable cervix who were undergoing preinduction cervical ripening with prostaglandin E2. The prostaglandin E2 was inserted into the posterior vaginal fornix as a single dose of either a 2.5 mg methylcellulose gel (20 cases) or 10 mg controlled-release pessary (20 cases). Uterine activity monitoring began 1 hour before dosing and continued for 12 hours. For those treated with the gel, low-amplitude, high-frequency contractions began within the first hour, reached a peak within 4 hours, and initiated sustained high-amplitude contractions in 10 (50%) cases. With the controlled-release pessary, low-amplitude, high-frequency contractions had a slightly later onset, reached a peak between the fifth and eighth hours, and initiated sustained high-amplitude contractions in 18 (80%) cases. Uterine hyperstimulation occurred in two (10%) pessary cases, with no adverse effect after removal. We conclude that low-amplitude, high-frequency uterine contractions began with either method of intravaginal prostaglandin E2 delivery but led to sustained, high-amplitude contractions primarily with the pessary.

Administration, Intravaginal↗
PubMed1991

Correlations and apparent contradictions in assessment of oxidant stress status in vivo.

Oxidative modifications of biological molecules are essential, but uncontrolled or excessive oxidative activities appear to contribute to many disease states. The mechanisms through which excess oxidant activities cause injury have been studied most extensively for acute responses, particularly for drug-induced tissue damage and cell death, but substantial evidence suggests that chronically elevated oxidative activity may contribute to the development of diseases such as cancer. It is important that the correlation between oxidant stress status and cancer risk be examined directly in humans. A number of methods have been developed for assessing oxidant activities by measuring oxidized products in biological systems, but cross-comparison studies of these different methods are needed. In studies of mechanisms of acute hepatotoxicity, assessments of oxidant stress responses by different analytical methods often have provided data that appear at first glance to be contradictory. Marked oxidant stress responses may be indicated by one or more methods of analysis despite the lack of detectable change in other parameters, whereas in a second experimental model the responses may be reversed. These observations emphasize the need to integrate different analytical approaches into the assessment of oxidant activity in vivo and illustrate the importance for developing a better understanding of the chemical and physiological mechanisms through which the analytical methodologies are related.

Cell Survival↗
PubMed1991

Failed induction of labor despite sequential prostaglandin E2 therapy.

Preinduction cervical ripening with prostaglandin E2 (PGE2) is useful in minimizing the chances for a failed induction of labor. The lack of sufficient cervical dilation despite PGE2 and oxytocin therapy is uncommon. This investigation was undertaken to determine reasons for any failed inductions in pregnancies with pregel Bishop scores 4 or lower and requiring delivery within 24 hours. Fifteen (12.1%) of 124 eligible patients had failed inductions despite two 2.5 mg intravaginal doses. A finding in all the failures was a very unfavorable cervix (pregel Bishop score 0 to 2). The need for preterm delivery (33 to 37 weeks) was a common finding in the presence of a very unfavorable cervix. The data suggest that complicated pregnancies requiring delivery within 24 hours and failing to respond to sequential PGE2 therapy in the presence of a very unfavorable cervix may benefit from cesarean section without a prolonged induction.

Administration, Intravaginal↗
PubMed1991

Fetal habituation to vibroacoustic stimulation in uncomplicated term pregnancies.

The use of transabdominal vibroacoustic stimulation has been shown to improve the efficiency of antepartum fetal surveillance. The ability of the fetus to habituate to such a stimulus has also been suggested as a means of assessing the function of the central nervous system. The purpose of this blinded prospective investigation was to evaluate fetal habituation in a group of low-risk pregnancies anticipated to deliver within 1 week. One hundred sixteen uncomplicated pregnancies underwent repetitive vibroacoustic stimulation using a Corometrics Model 146 fetal acoustic stimulator. Fetal habituation was defined as a sustained elevation of the heart rate baseline for more than 15 minutes or a failure to produce an adequate acceleration of the fetal heart rate after an initial response. Habituation was present in 106 (91.4%) cases, whereas 10 (8.6%) failed to habituate to the stimulus. All infants failing to habituate in utero ultimately did well after delivery. Their birthweights, Apgar scores, umbilical artery blood gas determinations, and courses in the newborn nursery were similar to those of infants who responded to in utero sound stimulation. However, cesarean delivery for fetal distress and gross placental abnormalities (such as infarction and abruption) occurred more commonly in those fetuses failing to habituate. Additional investigations of fetal habituation to a vibroacoustic stimulus may be helpful in the intrapartum risk assessment of uncomplicated term pregnancies.

Acoustic Stimulation↗
PubMed1991

The failure of skin grafting to break tolerance to class I-disparate renal allografts in miniature swine despite inducing marked antidonor cellular immunity.

Long-term specific tolerance to one haplotype class I plus minor antigen disparate renal allografts develops without exogenous immunosuppression in approximately 35% of miniature swine (n = 128). Previous studies have suggested that this phenomenon is related to limited class I-specific helper T cell activity as evidenced by the failure of antibody class switching in vivo and the ability of exogenous interleukin 2 to elicit antidonor responses in vitro. To determine whether tolerance could be broken by inducing antidonor reactivity with donor antigen and a source of T cell help, multiple skin grafts bearing donor class I plus third-party class II antigens were placed on tolerant animals. Skin grafts were placed at least 3 months after the kidney transplant, at which time all recipients had normal renal function as measured by blood urea nitrogen and serum creatinine. First-set rejection of skin grafts by SLAad and SLAdd hosts occurred in 11.8 +/- 1.1 days (mean +/- SEM, n = 6) and in 9.3 +/- 0.9 days (n = 4), respectively. Coincident with skin rejection, most animals developed a transient rise in BUN to 62 +/- 11 mg/dl (n = 10) and a similar rise in Cr to 4.9 +/- 1.2 mg/dl (n = 10), with normal levels returning in all animals within two weeks. Subsequent skin grafts with the same disparity did not undergo second-set rejection and did not induce BUN or Cr elevations. Prior to skin grafting, animals showed no antidonor activity in mixed lymphocyte reaction or cell-mediated lymphocytotoxicity assays. After two skin grafts, all animals developed donor-specific CML and secondary MLR responses, and additional skin grafts amplified this cellular immunity. Development of marked antidonor immunity without a break in tolerance suggested that either graft adaptation or local suppression might be involved in maintaining tolerance to class I MHC antigens. In preliminary studies, an immunized SLAad animal and an immunized SLAdd animal were retransplanted with kidneys MHC matched to their first allografts. In both cases, the second graft was accepted permanently without immunosuppression, suggesting that graft adaptation is not necessary for the maintenance of tolerance to renal allografts in miniature swine.

Animals↗
PubMed1991

Comparison of patient-controlled analgesia and epidural morphine for postcesarean pain and recovery.

A greater awareness of the advantages and limitations of new methods of administering postcesarean analgesia would help the obstetrician care for the recovering patient. Patient-controlled analgesia and epidural morphine are two new modalities for postoperative pain relief. The purpose of this prospective investigation was to compare their effectiveness, safety, side effects, patient satisfaction and cost. During an eight-month period, 161 women undergoing cesarean delivery were assigned to receive narcotics by either epidural morphine (76 patients) or patient-controlled analgesia (85 patients) using a combined continuous infusion and demand dosing of meperidine. The demographic characteristics of the two groups were similar. Mild or no pain was reported with similar frequencies in both groups. No reduced respiration or undesired sedation was seen in either group. The postoperative times before sitting at the bedside, ambulating, tolerating clear liquids and leaving the hospital were also comparable. No complications were encountered with patient-controlled analgesia, but pruritus and alarms from apnea monitors occurred commonly in the epidural morphine group. The costs to the patient were similar for the two groups. Patient-controlled analgesia using a combined continuous infusion and demand dosing is an acceptable alternative to epidural morphine after cesarean delivery.

Adult↗
PubMed1991

Prenatal ultrasound diagnosis of a fetal inguinal hernia containing small bowel.

A scrotal mass measuring 5.9 X 4.8 cm was identified during an ultrasound examination. The presence of intestine within the mass was suspected based on visualized peristaltic waves. After delivery, the diagnosis of an inguinal hernia containing small bowel was confirmed. To our knowledge, this case represents the first report of an inguinal hernia containing small bowel diagnosed by prenatal ultrasound.

Adult↗