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Biomedical subjects

D D McIntire

Publications and source records attributed to D D McIntire.

At least 37 records · Page 2Linked to original sources

Postpartum regression rates of antepartum cervical intraepithelial neoplasia II and III lesions.

OBJECTIVE: To study the histologic regression and progression rates of cervical intraepithelial neoplasia (CIN) II and III after delivery and the effect the route of delivery has on the regression rates of CIN. METHODS: Pregnant patients with satisfactory colposcopic examinations and biopsy-proven CIN II and III were identified. Delivery information and postpartum biopsy results were obtained by chart review. RESULTS: Two hundred seventy-nine patients had antepartum biopsies of CIN II or CIN III. Of these, 126 women were excluded for the following reasons: lost to follow-up (75), human immunodeficiency virus positive (two), cesarean hysterectomy (four), and inadequate postpartum follow-up (45). This yielded a study group of 153 patients consisting of 82 with CIN II and 71 with CIN III. The regression rates were 68% and 70% among CIN II and CIN III patients (P = .78), respectively. Seven percent of patients with CIN II progressed to CIN III on postpartum evaluation. Twenty-five percent of those patients with CIN II and 30% of those with CIN III remained the same postpartum. No CIN lesions progressed to invasive carcinoma. There were no differences in regression rates or progression rates among the women who had vaginal deliveries (130), women who labored and then underwent cesarean (17), or women who proceeded to a cesarean without laboring (six). CONCLUSION: We found similar high postpartum regression rates despite the route of delivery. We recommend conservative antepartum management with postpartum colposcopic evaluation regardless of route of delivery because we are unable to predict which of these lesions are more likely to regress.

Adult↗

Severe preeclampsia and the very low birth weight infant: is induction of labor harmful?

OBJECTIVE: To compare the effects of labor induction with the effects of cesarean delivery without labor on neonatal outcome in pregnancies complicated by severe preeclampsia and delivery of very low birth weight infants. METHODS: This was a retrospective study of 278 singleton, live-born infants who weighed 750-1500 g and were delivered because of severe preeclampsia between 1988 and 1997. Outcomes of infants delivered by cesarean without labor were compared with those of infants exposed to labor induction. Statistical analysis was performed using Student t test, Mann-Whitney U test, chi2 analysis, and Fisher exact test, where appropriate. Multiple logistic regression analysis was used to adjust for outcomes of interest. RESULTS: One hundred forty-five (52%) of the 278 women with severe preeclampsia who delivered infants weighing between 750 and 1500 g had labor induced and 133 (48%) delivered by cesarean without labor. Vaginal delivery was accomplished by 50 (34%) women in the induced group. Apgar scores of 3 or less at 5 minutes were more likely in the induced-labor group (6 versus 2%, P = .04), but other neonatal outcomes, including respiratory distress syndrome, grade 3 or 4 intraventricular hemorrhage, sepsis, seizures, and neonatal death, were similar in the two groups. Adjustment for birth weight and gestational age did not affect those results. Analysis of data from the induced-labor group did not reveal an effect by route of delivery on neonatal outcome. CONCLUSION: Induction of labor in cases of severe preeclampsia is not harmful to very low birth weight infants.

Adult↗

Fetal pulse oximetry: duration of desaturation and intrapartum outcome.

OBJECTIVE: To analyze labor outcomes in relation to masked fetal arterial oxyhemoglobin saturation values above or below 30%. METHODS: Consenting gravidas with uncomplicated pregnancies at or beyond 36 weeks' gestation underwent continuous fetal pulse oximetry. Pregnancy outcomes were compared between two groups: women with fetuses with at least one epoch of arterial oxyhemoglobin saturation below 30% (10 seconds or longer) and women with fetuses without such an episode. We also attempted to ascertain whether duration of saturation below 30% correlated with fetal compromise. RESULTS: We measured arterial oxyhemoglobin saturation in 129 fetuses, 69 (53%) of whom had at least one epoch of saturation below 30%. There were no statistically significant differences in labor and delivery outcomes between the high-saturation and low-saturation groups (eg, cesarean delivery: 13 versus 9%, P = .41; umbilical artery [UA] pH less than 7.20: 10 versus 9%, P > .999). However, as duration of fetal arterial oxyhemoglobin saturation below 30% increased from 10 seconds to longer than 9 consecutive minutes, the incidence of fetal compromise (considered present when at least one of the following criteria was met: cesarean delivery for nonreassuring fetal heart rate pattern, UA pH less than 7.20, admission to the special care nursery, or 5-minute Apgar score not more than 3) increased significantly (P = .002). The threshold duration of fetal arterial oxyhemoglobin saturation below 30% associated with increased fetal compromise was 2 minutes. CONCLUSION: Transient fetal arterial oxyhemoglobin saturation values below 30% are common during normal labor and did not predict fetal compromise. Fetal arterial oxyhemoglobin saturation values less than 30% for 2 minutes or longer might be associated with fetal compromise.

Adult↗

Outcome of twin pregnancies according to intrapair birth weight differences.

OBJECTIVE: To assess the clinical significance of twin intrapair birth weight differences. METHODS: This was a retrospective study of twin pregnancy outcomes. Intrapair birth weight differences were stratified into the following six groups: 14% or less, 15-20%, 21-25%, 26-30%, 31-40%, and 41% or more using the larger infant as the growth standard. Statistical analysis was done using the Mantel-Haenzel chi2 test. RESULTS: We studied 1370 consecutive women who delivered at Parkland Hospital, Dallas, Texas, between January 1, 1988, and December 31, 1996, and had twin gestations and live births or fetal deaths within 7 days of delivery. Greater birth weight discordance was significantly associated with preterm delivery due to intervention (P<.001). Noncephalic-cephalic presentations and cesarean delivery were also associated with greater discordance (P = .001 and .02, respectively). Neonatal morbidities, including low birth weight, intensive care admission, and respiratory distress, were all associated with higher birth weight discordance. Fetal abnormalities were more common with increased discordance (P<.001). Greater birth weight discordance was also associated with intrauterine fetal death. There were no differences in outcome for the smaller compared with the larger twin of the twin pair. CONCLUSION: Twin birth weight discordance is problematic because severe divergent fetal growth increases the risk of fetal death and leads to obstetric intervention and consequent neonatal morbidity due to prematurity.

Adult↗

Epidural analgesia during labor and maternal fever.

BACKGROUND: In recent observational studies, epidural analgesia during labor at patient request has been associated with maternal fever. The authors report a secondary analysis of fever in women who were randomized to receive either epidural or patient-controlled intravenous analgesia during labor. METHODS: Maternal tympanic temperature was measured during spontaneous labor in 715 women at term who were randomized to either epidural analgesia with bupivacaine and fentanyl or to patient-controlled intravenous analgesia with meperidine. Intent-to-treat analysis of women with fever (temperature > or = 38.0 degrees C) versus those without was performed using Student t test and Fisher exact test to determine statistical significance (P < 0.05). RESULTS: Epidural analgesia was associated with maternal fever (odds ratio = 4.0; 95% confidence interval = 2.0-7.7), as was nulliparity (odds ratio = 4.1; 95% confidence interval = 1.8-9.1) and labor longer than 12 h (odds ratio = 5.4; 95% confidence interval = 2.9-9.9). These factors were all independent variables for maternal fever when analyzed using logistic regression. CONCLUSIONS: Epidural analgesia is associated with maternal fever. However, nulliparity and dysfunctional labor are also significant cofactors in the fever attributed to epidural analgesia.

Analgesia, Epidural↗

Lack of effect of walking on labor and delivery.

BACKGROUND AND METHODS: Walking during labor may reduce patients' discomfort and improve outcomes. We conducted a randomized trial of walking during active labor to determine whether it altered the duration of labor or other maternal or fetal outcomes. Women with uncomplicated pregnancies between 36 and 41 weeks' gestation and in active labor were randomly assigned either to walking or to no walking (usual care). Pedometers were used to quantify walking, and the time spent walking was recorded. RESULTS: Of the 536 women assigned to the walking group, 380 actually walked. Their mean (+/-SD) walking time was 56+/-46 minutes. There were no significant differences between the women assigned to the walking group and the 531 women assigned to the usual-care group in the duration of the first stage of labor (6.1 hours in both groups, P=0.83), the need for labor augmentation with oxytocin (23 percent vs. 26 percent, P=0.25), and the use of analgesia (84 percent vs. 86 percent, P=0.59). Similarly, the percentages of women requiring delivery by forceps (4 percent vs. 3 percent, P=0.35) and cesarean section (4 percent vs. 6 percent, P=0.25) were not significantly different. These labor and delivery outcomes were unrelated to walking in both nulliparous and parous women. The infants' outcomes were also similar in the two study groups. CONCLUSIONS: Walking neither enhanced nor impaired active labor and was not harmful to the mothers or their infants.

Adult↗

The course of labor with and without epidural analgesia.

OBJECTIVE: Our purpose was to measure effects of epidural analgesia on labor compared with boluses of meperidine in a cohort of women with similar clinical circumstances. STUDY DESIGN: One hundred ninety-nine nulliparous women who were delivered spontaneously at term and who received oxytocin for labor augmentation before the initiation of analgesia were identified for analysis. All these women were managed in a low-risk labor unit according to a standardized protocol. This management protocol encouraged early amniotomy and the use of oxytocin when ineffective labor was diagnosed. RESULTS: The demographic characteristics of the two study groups were similar with respect to age, height, weight, and maternal age. The two groups had the same cervical dilatation on admission (3.3 cm) and at the time of analgesia administration (4.1 vs 4.2 cm), indicating similar progress of labor before oxytocin administration. The length of the active phase of labor was longer in the epidural group (7.9 vs 6.3 hours, p = 0.005), as was the second stage (60 vs 48 minutes, p = 0.03). The mean and maximal rates of oxytocin infusion were similar between the two study groups; however, the amount of oxytocin required for each centimeter of cervical change was more in the epidural group (22 vs 16 mU per cm of cervical change, p = 0.009). Neonatal outcomes were unaffected by the type of labor analgesia. CONCLUSION: Epidural analgesia decreases uterine performance during oxytocin-stimulated labor, resulting in an increase in the length of the first and second stages of labor.

Adolescent↗

Does magnesium sulfate given for prevention of eclampsia affect the outcome of labor?

OBJECTIVE: The purpose of this study was to determine whether magnesium sulfate given for prevention of eclampsia affected labor outcomes compared with phenytoin, which is not known to impede uterine activity when given in anticonvulsant doses. STUDY DESIGN: Secondary analysis was performed of a study of women with pregnancy-induced hypertension who were admitted for delivery and randomly assigned to receive either magnesium sulfate or phenytoin for eclampsia prophylaxis. Nulliparous women with a singleton pregnancy in cephalic presentation at term were selected for analysis in an effort to limit the influence of confounding variables such as preterm birth and malpresentations on labor management and outcomes. Similarly, women who had severe preeclampsia and who received labor epidural analgesia were excluded. RESULTS: A total of 2138 women were randomized to receive magnesium sulfate or phenytoin in the primary study. A total of 905 nulliparous women met the inclusion criteria for this secondary analysis; 480 had been randomized to phenytoin and 425 were given magnesium sulfate. The two groups were similar demographically. Labor outcomes such as (1) oxytocin stimulation, (2) admission-to-delivery intervals, (3) prolonged second-stage labor, (4) forceps delivery, and (5) cesarean delivery were not affected by maternal treatment with magnesium sulfate. CONCLUSION: Compared with phenytoin, magnesium sulfate given for intrapartum treatment of pregnancy-induced hypertension does not significantly affect labor outcomes.

Adult↗

Abdominal aortic aneurysms and malignant neoplasia: double jeopardy.

BACKGROUND: This study was performed to determine whether there is a significant association between abdominal aortic aneurysms (AAAs) and malignancy and to determine the impact of malignancy on late survival in patients with AAA. METHODS: We studied 126 men undergoing AAA repair and compared them with 99 men undergoing aortofemoral bypass (AFB) for occlusive disease and with 100 men undergoing herniorrhaphy during the same period. RESULTS: Fifty-one (40%) patients with AAA, 23 (23%) patients undergoing AFB, and 21 (21%) patients undergoing herniorrhaphy were diagnosed with cancer (p = 0.002). By life table analysis the proportion of subjects remaining cancer free at 5 years was 0.60 +/- 0.05 for AAA, 0.83 +/- 0.04 for AFB, and 0.81 +/- 0.04 for herniorrhaphy (p = 0.004). Multivariate analysis selected four independent risk factors for cancer: presence of AAA (p = 0.003, odds ratio 1.4, confidence interval [CI] 1.2 to 1.7), age (p = 0.001, odds ratio per year 1.1, CI 1.0 to 1.1), smoking (p = 0.04, odds ratio 1.5, CI 1.0 to 2.2), and hypertension (p = 0.04, odds ratio 0.73, CI 0.5 to 1.0). Cancer deaths accounted for 32% of late deaths in patients with AAA, which was not different compared with 26% of late deaths in patients undergoing AFB and 36% of late deaths in patients undergoing herniorrhaphy. Five-year cancer-free survival was 0.44 +/- 0.05 for patients with AAA, 0.64 +/- 0.05 for patients undergoing AFB, and 0.70 +/- 0.05 for patients undergoing herniorrhaphy (p < 0.001, AAA versus herniorrhaphy only). CONCLUSIONS: Cancer is more prevalent in men with AAA than in men undergoing AFB or herniorrhaphy. The presence of AAA appears to be an independent risk factor for cancer. Despite the higher cancer prevalence in patients with AAA, cardiovascular disease accounted for the largest number of late deaths in this series, minimizing differences in cancer-free survival between patients with AAA and patients undergoing AFB.

Aged↗

Risk of concurrent prostate cancer in cystoprostatectomy specimens is related to volume of high-grade prostatic intraepithelial neoplasia.

OBJECTIVES: To assess the relationship of prostatic intraepithelial neoplasia (PIN) with both incidental and clinical carcinoma of the prostate. METHODS: We retrospectively reviewed prostate histology in 48 men (group 1) who underwent surgical removal of the prostate for diagnoses other than prostate cancer, as well as in 64 men (group 2) who underwent radical prostatectomies. Both groups were assessed for the presence and extent of high-grade (HG-) PIN and compared with respect to patient age, Gleason score, and volume of prostate cancer. RESULTS: HG-PIN was present in 40 of 48 (83%) group 1 cases. Forty-six percent of these cases (22 of 48) had incidental prostate cancer. Twenty-nine of 48 (60%) group 1 patients with HG-PIN had multifocal or extensive disease. Twenty of 22 (91%) incidental prostate cancers were present in 29 prostates with multifocal or extensive HG-PIN. In contrast, only 2 of 19 (11%) cases with absent to focal HG-PIN had prostate cancer. The association of multifocal or extensive HG-PIN with incidental prostate cancer was significant (P = 0.001); the relationships of extent of HG-PIN and cancer volume (P = 0.06) or high Gleason score (P = 0.017) were not significant. HG-PIN was present in 61 of 64 (95%) group 2 cases. The associations of extent of HG-PIN and cancer volume (P = 0.169) or high Gleason score (P = 0.156) were not significant. CONCLUSIONS: Both the low rate of incidental prostate cancer in specimens with absent to focal HG-PIN and the high rate of cancer in specimens with multifocal or extensive HG-PIN suggest that HG-PIN is a marker for concurrent prostate cancer and that the risk of concurrent prostate cancer is related to the volume of HG-PIN in the prostate gland.

Aged↗

Interphase cytogenetic (in situ hybridization) analysis of astrocytomas using archival, formalin-fixed, paraffin-embedded tissue and nonfluorescent light microscopy.

Astrocytomas contain nonrandom chromosomal abnormalities that recently have been correlated with shortened patient survival. Two frequently reported aberrations are trisomy 7 and monosomy 10. We assessed the numerical complement of chromosomes 7 and 10 in formalin-fixed, paraffin-embedded brain biopsy tissue from 28 diffuse astrocytomas by in situ hybridization using a nonfluorescent enzymatic detection system. Clinical follow-up of at least 5 years was available in 26 cases (93%). Monosomy 10 was identified in 7 cases (25%): astrocytoma, 1 case; anaplastic astrocytoma, 1 case; and glioblastoma, 5 cases. Trisomy 7 was identified in 11 cases (39%): astrocytoma, 5 cases; glioblastoma, 6 cases. Multivariate analysis revealed that monosomy 10 was the most statistically significant negative predictor of patient survival. Numerical chromosomal abnormalities are detectable in astrocytomas in archival tissue using interphase cytogenetics and nonfluorescent light microscopy. Although larger studies are required, our data suggest that potentially useful prognostic information may be obtained with this approach.

Adult↗

Noninvasive capnometry monitoring for respiratory status during pediatric seizures.

OBJECTIVE: To determine the reliability and clinical value of end-tidal CO2 by oral/nasal capnometry for monitoring pediatric patients presenting post ictal or with active seizures. DESIGN: Clinical, prospective, observational study. SETTING: University affiliated children's hospital. INTERVENTIONS: One hundred sixty-six patients (105 patients with active seizures, 61 post ictal patients) had end-tidal CO2 obtained by oral/nasal sidestream capnometry, and respiratory rates, oxygen saturation, and pulse rates recorded every 5 mins until 60 mins had elapsed. End-tidal CO2 values were compared with a capillary PCO2 and clinical observation. MEASUREMENTS AND MAIN RESULTS: The mean end-tidal CO2 reading was 43.0 +/- 11.8 torr [5.7 +/- 1.6 kPa] and the mean capillary PCO2 reading was 43.4 +/- 11.7 torr [5.7 +/- 1.6 kPa]. The correlation between end-tidal CO2 and capillary PCO2 was significant (r2 = .97; p < .0001). A relative average bias of 0.33 torr (0.04 kPa) with end-tidal CO2 lower than capillary PCO2 was established with 95% limits of agreement +/-4.2 torr (+/-0.6 kPa). Variability of difference scores was not related to range of mean scores (r2 = .00003), age (r2 = .0004), or respiratory rates (r2 = .0009). End-tidal CO2 (r2 = .22; p < .001) correlated better with respiratory rate changes when compared with oxygen saturation (r2 = .02; p = .01). CONCLUSIONS: Dependable end-tidal CO2 values can be obtained in pediatric seizure patients using an oral/nasal cannula capnometry circuit. Continuous end-tidal CO2 monitoring provides the clinician with a reliable assessment of pulmonary status that can assist with decisions to provide ventilatory support.

Adolescent↗

Effects of in vivo cocaine administration on human platelet aggregation.

To evaluate whether cocaine administration to human volunteers in vivo increases platelet aggregation, 12 healthy male volunteers were studied twice in a prospective, double-blinded fashion. There was a decrease in aggregation following cocaine exposure compared to placebo, which was most prominent at high doses of adenosine diphosphate.

Adult↗

HIV transmission during invasive radiologic procedures: estimate based on computer modeling.

OBJECTIVE: The primary purpose of this study was to estimate the risk of HIV transmission from physicians to patients during invasive radiologic procedures and to compare this estimate with those previously derived for surgical procedures so that policy on possible practice restrictions can be decided. The risk of HIV transmission from patient to physician, including cumulative career risk for interventional radiologists, was also estimated. MATERIALS AND METHODS: The risk of HIV transmission from physician to patient and vice versa was estimated with computer modeling techniques, using available data on prevalence of HIV infection, rates of injury during invasive radiologic procedures, and risk of viral transmission after an exposure. Cumulative career risk of occupational infection was estimated with a computer simulation model. RESULTS: If the physician's HIV status is unknown, the risk of transmission of HIV to a patient during a procedure is estimated to be 0.03 per million procedures (95% confidence interval, 0-3.8 per million procedures). If the physician is known to be HIV-positive, the risk of transmission to a patient is estimated to be 7.5 per million procedures (95% confidence interval, 0-15.3 per million procedures). The estimated risk of transmission from patient to physician ranges from 0.03 to 7.5 per million for a single procedure, and the cumulative risk of occupational HIV infection over 30 years is estimated to be 0.009-16%. CONCLUSION: The estimated risk of HIV transmission from physician to patient during invasive radiologic procedures is so low that global practice restrictions on HIV-infected interventional radiologists are not warranted. As recommended by the American Medical Association and the Centers for Disease Control, decisions on possible practice restrictions should be made on a case-by-case basis rather than a priori. The risk of HIV transmission from patient to physician is also low, but real. The cumulative career risk of occupational infection with HIV may vary widely based on individual circumstances and the patient population served.

Computer Simulation↗

Allele-specific loss in chromosome 9p loci in preneoplastic lesions accompanying non-small-cell lung cancers.

BACKGROUND: Carcinogenesis is a multistep process, which may begin as a consequence of chromosomal changes. Deletions in the short arm of chromosome 9 (9p) have been observed in lung carcinomas. In addition, morphologically recognizable preneoplastic lesions, frequently multiple in number, precede onset of invasive carcinomas. PURPOSE: We tested for deletions and loss of heterozygosity (LOH) at 9p loci in preneoplastic and neoplastic foci in lungs of patients with non-small-cell lung carcinomas (NSCLCs). METHODS: Seven archival, paraffin-embedded, surgically resected NSCLC specimens were selected. They were predominantly from patients with adenocarcinomas and contained multiple preneoplastic lesions, including hyperplasia, metaplasia, dysplasia, and carcinoma in situ (CIS). Fifty-three histologically identified preneoplastic and malignant lesions present in bronchi, bronchioles, and alveoli were precisely microdissected from stained tissue sections with a micromanipulator. Stromal lymphocytes were used to determine constitutional heterozygosity. The specimens were analyzed for LOH using polymerase chain reaction-based assays for polymorphism in dinucleotide repeats (microsatellite markers) in interferon alfa (IFNA) and D9S171 loci on 9p. RESULTS: All seven cases were constitutionally heterozygous for one or both microsatellite markers. Five of seven cases had LOH at one or both 9p loci in the invasive primary cancers (doubly informative cases). Four of these five cases also revealed LOH in preneoplastic foci. In the doubly informative cases, LOH was detected in five (38%) of 13 foci of hyperplasia, four (80%) of five foci of dysplasia, and three (100%) of three CIS lesions. LOH was detected in preneoplastic lesions from all regions of the respiratory tract, including bronchi, bronchioles, and alveoli, and involved five different cell types. The identical allele was lost from both the preneoplastic lesions and the corresponding tumors (12 of 12 lesions, 17 of 17 comparisons), a phenomenon we have referred to as "allele-specific mutation." Statistical analyses employing a cumulative binomial test demonstrated that the probabilities of such findings occurring by chance are 2.4 x 10(-4) and 7.6 x 10(-6), respectively. From comparisons with the previously published data on other chromosomal abnormalities in the same tissue specimens, it appears that LOH at 3p and 9p loci occurred early in the hyperplasia stage, but the ras gene point mutations were relatively late, at the CIS stage. CONCLUSIONS: LOH at 9p loci occurs at the earliest stage in the pathogenesis of lung cancer and involves all regions of the respiratory tract. LOH in NSCLC is not random but targets a specific allele in individuals. Studying preneoplastic lesions may help identify intermediate markers for risk assessment and chemoprevention.

Adenocarcinoma↗

Locus coeruleus cell loss in the aging human brain: a non-random process.

Quantitative neuroanatomical techniques were used to determine whether with aging there is random or systematic loss of locus coeruleus (LC) neurons in the human brain. The cells were identified by immunohistochemical staining for the catecholaminergic enzyme tyrosine hydroxylase and/or by neuromelanin pigment content. Cell locations were mapped, using computer imaging procedures, in horizontal sections spaced 0.5 to 0.8 mm throughout the rostrocaudal extent of the nucleus in 17 cases, from 1 to 104 years of age. Neuromelanin pigment accumulated within the neurons with aging. In brains less than 25 years of age there were many fewer pigment-containing neurons than tyrosine hydroxylase-containing neurons; however, by the fifth decade the number of cells identified by the two markers was comparable. From the first to the tenth decade of life there is over a 50% loss of LC neurons: in four cases from "young" individuals (1-28 years of age) there were 21,084 +/- 653 tyrosine hydroxylase immunostained cells (mean +/- standard error of the mean) on one side of the brain; in seven cases from "old" individuals (60-82 years of age) there were 16,502 +/- 921 pigment-containing cells; and in the three cases from the "oldest" individuals (103-104 years of age) there were 9,493 +/- 1,236 pigment-containing neurons. In both the "old" and "oldest" groups, compared to the "young," there was significantly greater loss of rostral cells than caudal cells. These data indicate a systematic loss of cells such that the rostral, forebrain-projecting neurons decrease in number with aging to a greater extent than do the caudal, spinal cord-projecting neurons.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗