Biomedical subjects
Publications and source records attributed to T R Johnson.
A relationship between cocaine use and extensive rupture of a uterine scar has not been reported. We report such a case with extensive laceration of the maternal urinary bladder occurring after ingestion of cocaine.
OBJECTIVE: Previous studies have shown that twins, when monitored simultaneously, show a remarkably high incidence of coincident fetal heart rate accelerations (about 58%). The current study examines synchrony of behavior patterns in twins. STUDY DESIGN: We examined 37 fetal monitor strips from 15 sets of twins with simultaneous fetal heart rate and fetal movement recorded by means of Doppler techniques (Toitu MT-430 fetal actocardiograph). The strips were analyzed for coincidence of fetal heart rate accelerations and fetal movement episodes and then conceptually for synchrony of fetal behavior patterns on the basis of descriptions of behavioral states by Prechtl. RESULTS: Thirty-six percent of fetal heart rate accelerations were found to be simultaneous. Forty-three percent of movement epochs were considered simultaneous. We found that twins exhibited synchronous behavior patterns (basically sleep or awake state) 94.7% of the time. CONCLUSION: Twin-twin interactions are more consistently related than suspected when observation is limited to heart rate alone, and the synchrony and role of fetal behavior states must be considered when twin interactions and behavior are studied.
Beat-to-beat variability (BTBV) of the fetal heart rate (FHR) is considered an indication of the neural integrity and is an important prognostic indicator of fetal well-being. We report the initial evaluation of a recently developed abdominal fetal ECG (AFECG) mode of FHR monitoring using Adaptive Digital Filtering (ADF) to accurately obtain BTBV noninvasively. Five women in labor at term were monitored with the direct fetal scalp electrode (FSE) and simultaneously with the AFECG using ADF. A computer analysis of 3298 seconds (55 minutes) of data provided a one-to-one comparison of the R-R intervals. One analysis of the direct FSE data with a second simultaneous analysis from the same electrode, to serve as control, was compared with the noninvasive AFECG data. The study group has a standard deviation of only 1.50 bpm compared to 0.79 bpm for the control group. The AFECG method agrees with the direct FSE method within 1 bpm for 92.6% of the reported R-R intervals and within 2 bpm for 98.9% of the reported intervals. This new noninvasive AFECG technique with ADF provides a continuous record of instantaneous FHR and BTBV that may be relied upon to provide an accurate continuous clinical record. The reliability of the technique has yet to be determined over a wide range of subjects.
LiverSoar is a flexible knowledge-based system that can learn from its problem-solving experience in individual cases. Within an opportunistic abductive framework, it can diagnose liver diseases from findings in liver tissue biopsies. As more cases are encountered and more recognition knowledge is acquired, the system becomes prepared for most of the usual cases, hence solves them with less problem-solving effort. At the same time, it stays flexible enough to fall back to deliberative problem solving in more unusual cases if the acquired knowledge does not apply.
Abduction, or inference to a best explanation, is a ubiquitous type of inference that is frequently used by humans in a wide range of tasks. However, many realistic domains have properties that make abduction computationally intractable (i.e., where the time to reach a solution increases exponentially with the number of possible explanations). We present a domain task analysis and performance evaluation of RedSoar, a plausible cognitive computational model of abduction, that accomplishes the antibody identification task in immunohematology. The task analysis reveals how a computationally intractable abductive problem, where one is seeking optimal solutions, can be reformulated to be a computationally tractable abductive problem, by seeking satisfactory rather then optimal solutions. From the satisfactory perspective, our evaluation framework of RedSoar's performance explores the computational benefits and costs of having directly available abstract hypothesis formation knowledge, and how a strong causal constraint between hypotheses and data reduces the combinatorial explosion of constructing a best explanation.
Using several specific genetic diseases as examples, this article has illustrated basic genetic principles that can be applied to many clinical situations. Practicing obstetricians must be aware that advances are being made daily in the care of patients with inherited disorders and in prenatal diagnosis. A fundamental understanding of human genetics is essential in order to offer optimal care for patients during their reproductive years.
OBJECTIVE: The purpose of this study was to determine the clinical value of identified coupling of fetal heart rate (FHR) accelerations (more than five beats per minute for any duration) with objectively detected fetal movements. METHODS: One hundred sixty-six patients underwent routine fetal testing using a Doppler device that recognized both FHR and fetal movements. The coupling index was determined to be the percentage of fetal movements associated with FHR accelerations, and various coupling indices were compared with nonstress test (NST) results. RESULTS: A coupling index above 25% and below 75% compared well with the traditional NST by standard epidemiologic criteria and by the kappa statistic. CONCLUSION: Coupling of even small FHR accelerations and fetal movements could substitute for or replace the NST in antenatal screening.
BACKGROUND: In early 1990 fluconazole was introduced as a prophylactic antifungal agent after bone marrow transplantation. During the same year Candida krusei emerged as the chief candida pathogen among patients with bone marrow transplants. METHODS: To determine whether there was a correlation between the introduction of fluconazole and the increased incidence of C. krusei, we conducted a retrospective study based on the medical, mycologic, and autopsy records of all adult inpatients who had undergone bone marrow transplantation (n = 296) or who had leukemia (n = 167) at the study center during 1989 and 1990. RESULTS: The 84 patients who received antifungal prophylaxis with fluconazole had a sevenfold greater frequency of C. krusei infection than the 335 patients who did not receive fluconazole (8.3 percent vs. 1.2 percent, P = 0.002), despite having a lower frequency of disseminated C. albicans and C. tropicalis infections (0 vs. 6.0 percent, P = 0.02). Ten of the 11 C. krusei infections were controlled by a combination of amphotericin B and flucytosine. Colonization by C. krusei was found in 40.5 percent of the patients who received fluconazole but in only 16.7 percent of those who did not receive it (P less than 0.0001). Colonization was independently associated with the prophylactic use of both fluconazole (odds ratio, 3.50; P less than 0.001) and norfloxacin (odds ratio, 2.53; P = 0.04). C. krusei was not susceptible to fluconazole in vitro. CONCLUSIONS: In patients at high risk for disseminated candida infections, suppression of bacterial flora and the more common candida pathogens may permit some less pathogenic, but natively resistant candida species, such as C. krusei, to emerge as systemic pathogens.
The levels of several RNA transcripts in cultured hepatocytes are regulated by transcriptional and post-transcriptional mechanisms and are affected by growth hormone and insulin. We assessed the effects of these hormones on transcription rates and the stability of insulin-like growth factor I, actin, and albumin transcripts in intact cells of primary cultures of rat hepatocytes by analyzing thiol-labeled, newly synthesized RNA isolated by mercurated agarose affinity chromatography. The application of this concept to the measurement of transcript stability is presented in detail. The data indicate that growth hormone stimulates the transcription rates of insulin-like growth factor I, actin, and albumin genes. The stability of all three transcripts, particularly albumin, appears to be lower in growth hormone-containing medium than it is in insulin-containing medium. The experiments indicate that the rates of transcription and/or degradation of albumin mRNA are influenced by hormonal treatment. However, the cells maintain roughly constant albumin transcript levels independent of hormone treatment by compensatory changes in the rates of transcription and degradation.
A cDNA clone of 525 bp corresponding to the 3'-untranslated region of insulin-like growth factor-I was isolated from a human placenta library. The sequence of this clone extended 200 nucleotides downstream from the previously reported 3'-end of IGF-IA cDNA, indicating the existence of IGF-IA transcripts having an even larger 3'-untranslated region. By using this clone for RNA transfer blot hybridization, it was shown that this longer 3'-untranslated region is included in the 7.5- and 5.0-kb transcripts, but not in the 1.1- and 0.9-kb transcripts. It is also apparent that transcripts bearing the extended 3'-untranslated sequence are highly expressed in human placenta.
The stability of several RNA transcripts in cultured hepatocytes is known to increase when serum is omitted from the culture medium. In order to investigate possible mechanisms for this phenomenon, we examined the effects of actinomycin D and cycloheximide on the levels of actin, albumin, and insulin-like growth factor I transcripts in primary cultures incubated in serum-free medium. The levels of IGF-I and albumin transcripts per culture increased for the first 4 hours following addition of actinomycin D and then declined. The levels of actin transcripts and total RNA per culture declined immediately following actinomycin D addition in a manner consistent with exponential decay. IGF-I and albumin transcript levels were relatively unaffected by cycloheximide, while actin transcript levels increased 7-fold over 7 hours. The half-lives of actin transcripts and total RNA were calculated to be 4.6 to 7.7 hours and 11 to 19 hours, respectively, with no statistically significant correlation with hormone treatment. The data suggest that the stability of albumin and IGF-I transcripts, but not actin transcripts, is controlled in part by an actinomycin D-sensitive process.
The prognostic significance of antepartum fetal movement is well known; therefore it may be a variable in intrapartum fetal well-being. We report the simultaneous observation of fetal movement with fetal heart rate and uterine contractions by processed Doppler actograph signals during spontaneous labor of 22 normal women with normal fetal outcome. The mean percent incidence of fetal movement during labor was 17.3%. The percentage occurring during uterine contractions was 65.9%. Of all uterine contractions, 89.8% were associated with fetal movement. The proportion of time the fetus spent moving during uterine contractions (21.4%) was higher than between uterine contractions (12.9%). Uterine contractions associated with fetal movement were significantly longer than those not associated with fetal movement (p less than 0.0001). Mean percent incidence of fetal movement did not differ significantly between latent and active-phase labor. This study demonstrates a clear relationship between fetal movement and uterine contractions in labor.
A randomized prospective trial was performed to compare the efficacy and safety of ritodrine and indomethacin in the long-term treatment of preterm labor. Forty patients with intact membranes in preterm labor at 23 to 34 weeks' gestation were randomized to receive either intravenous ritodrine or oral indomethacin as the first-line tocolytic agent. Successful intravenous ritodrine therapy was followed by oral terbutaline therapy, and indomethacin-treated patients continued to receive oral indomethacin. Treatment failures were defined as progressive preterm labor or patient intolerance, and these patients were treated with intravenous magnesium sulfate. Ritodrine and indomethacin were equally successful in delaying preterm birth as defined by interval to delivery, gestational age at delivery, delivery delayed greater than 7 days, attainment of 35 weeks of gestation, percentage of patients who required magnesium sulfate therapy, percentage of patients who were readmitted with premature rupture of membranes, absence of recurrent preterm labor, and infant birth weight. More than 80% of mothers who received ritodrine voiced complaints of beta-sympathomimetic side effects, and one patient discontinued treatment as the result of intolerance. There were minimal patient complaints with indomethacin use. No statistically significant differences were noted in neonatal outcome as defined by Apgar scores, umbilical cord pH, intensive care days, ventilator days, or neonatal deaths. However, three cases of primary pulmonary hypertension were observed in the indomethacin group. We had not previously observed this problem with short-term (24 to 48 hours) indomethacin therapy.
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In order to more adequately characterize patterns of intrauterine growth retardation in twins, the mean birthweights of all nonanomalous white or black twins born between 24 and 41 weeks of gestation and surviving until discharge over an 11-year period (547 infants) and all similar singletons (19,072 infants) were compared by completed weeks of gestation. Between 24 and 35 weeks of gestation, the mean birthweights for the 547 twins and the 19,072 singletons were comparable and did not consistently differ statistically. From 36 to 41 weeks gestation, however, the difference became large, consistent, and statistically significant for each week at P less than 0.0001. This difference was present among all subgroups of twins, ie, in all males, females, blacks, and whites; it was still evident when the sample was further stratified by both race and sex (black males, white males, black females, white females). These data suggest a pattern of growth retardation in twins compared to singletons which is large, consistent, and statistically significant beginning at 36 weeks gestation. Clinically, these data also suggest the need for ultrasonic examination early in gestation (24-32 weeks) to document normal growth and to provide baseline data, and show the importance of such monitoring later in gestation, specifically after 36 weeks.
To determine whether large gestational weight gains result in higher maternal body weight within two years post-partum, we administered an anonymous survey to 423 mothers of twins at the Annual Twinsday Festival in Twinsburg, Ohio, in 1989 and 1990. Data collected included pregravid and current weight, age and parity, gestational weight gain and length of gestation. Data were grouped by patient age (18-24 years, 25-34 years and 35-44 years), parity (primipara or multipara) and length of gestation as preterm (less than 37 weeks) and term (greater than or equal to 37 weeks). Statistical analysis included paired t-tests, unpaired t-tests and chi-square as appropriate. Except for multiparas in the oldest age category, the mean current weight was higher than pregravid weight for each age and age/parity category. Comparison across age categories showed in pattern of increasing pregravid weight with increasing age for the total study sample (all women) and for primiparas; among multiparas, this trend was not as evident. Our findings suggest that large weight gains in twin gestations do not result in higher maternal body weight within two years postpartum. Such gains are associated with better intrauterine growth and should be considered when formulating weight gain recommendations for twin gestations.
Effects of prepartum energy intake, replacement of 25% of reticulorumen contents with water-filled bladders, and feeding of polyethylene glycol on DM intake during lactation were assessed in two trials. In trial 1, six rumen-cannulated cows were assigned to diets of either 1.50 or 1.68 Mcal NEL/kg 70 d prepartum. Animals fed the higher energy diet had greater NEL intake and tended to gain more BW prepartum. Intake from 28 to 70 d postpartum was not affected by prepartum diet but was reduced by 24.2 L of bladders placed in the rumen. Milk production tended to be increased for cows fed high energy prepartum and to be reduced by bladders. Total reticulorumen volume, digesta fractional passage rates, and acetate:propionate ratio were increased by bladders. In trial 2, eight rumen-cannulated cows, 28 d postpartum, received polyethylene glycol, 4% of diet DM, and 21.4 L of bladders in the rumen in a 2 x 2 factorial arrangement. Polyethylene glycol did not affect DM intake but reduced DM, CP, ADF, and NDF digestibilities. Bladders increased total reticulorumen volume, rumen fluid pH, and acetate:propionate ratio but decreased DM intake. Intake of DM was reduced .099 kg/L added bulk in trial 1 and .130 kg/L in trial 2. Compensation for replacement of rumen contents with inert bulk occurred by expansion of organ volume and, in trial 1, by a reduction in rumen retention time. These factors may explain why reductions in voluntary intake after addition of inert bulk to the reticulorumen often are proportionally lower than would be predicted from the volume of bulk added.
The use of Doppler ultrasound to study fetal blood flow has become commonplace, despite the lack of detailed evaluation of the testing tool for precision. In evaluation of 25 patients, no significant intraobserver differences were found between readings on an individual waveform, nor were there significant differences between different observers on individual waveforms. Temporally separated waveforms within a 30-minute window gave the greatest variation. A multi-way analysis of variance noted significant differences in this category only. This study confirmed the precision of measurements by a single observer and between observers. Only biological alterations over time displayed significant variability.