Biomedical subjects

J N Martin

Publications and source records attributed to J N Martin.

At least 37 records · Page 2Linked to original sources

PubMed2000

Invited commentary: determining specific sexual practices associated with human herpesvirus 8 transmission.

Laboratory and epidemiologic studies have established human herpesvirus 8 (HHV8) as an etiologic agent of Kaposi's sarcoma. With strong evidence linking HHV8 infection with the number of sexual partners among homosexual men, the challenge now is to determine the specific sexual acts associated with HHV8 transmission. Initial studies of specific practices, however, have differed in their conclusions; the paper by Dukers et al. in this issue of the Journal is the first to associate penile-oral intercourse with HHV8 transmission. Many sources of bias may contribute to the conflicting findings of studies reported to date: HHV8 research still lacks an adequately specific and sensitive serologic assay; identification of relevant exposure periods and measurement of sexual practices are imperfect; and sufficient adjustment for confounding is problematic. These numerous potential biases may be particularly important when trying to detect underlying associations that may be of low-order magnitude. The study by Dukers et al. (Am J Epidemiol 2000;151:213-24) is an important contribution to research on HHV8 transmission, but we do not yet know enough about the possible sexual routes of transmission to recommend avoiding any single behavior. For now, the best prevention advice is to reinforce the more general safe sex practices that have been promoted to prevent human immunodeficiency virus and other sexually transmitted diseases.

Herpesviridae Infections↗

PubMed2000

Amniotic fluid index and single deepest pocket: weak indicators of abnormal amniotic volumes.

OBJECTIVE: To compare amniotic fluid index (AFI) with the single deepest pocket in the identification of actual abnormal amniotic fluid (AF) volumes. METHODS: One hundred seventy-nine women with singleton pregnancies at the University of Mississippi between March 1994 and June 1999 had ultrasound estimations of AF volume sequentially using the AFI and single deepest pocket techniques. Each woman subsequently had ultrasound-directed amniocentesis with dye-dilution and spectrophotometric calculation of actual AF volume. RESULTS: Actual AF volumes were low (under 5% by volume for gestational age) in 62 women, normal (5-95%) in 100 women, and high (more than 95%) in 17 women. An AFI up to 5 cm (sensitivity 10%, specificity 96%) and a single deepest pocket up to 2 cm (sensitivity 5%, specificity 98%) were similarly inadequate in identifying dye-determined low AF volumes. Likewise, AFI above 20 (sensitivity 29%, specificity 97%) and a single-deepest pocket above 8 cm (sensitivity 29%, specificity 94%) were poor in identifying dye-determined abnormally high volumes. CONCLUSION: There was no difference between AFI and single deepest pocket techniques for identifying truly abnormal AF volumes. Both techniques were unreliable for identifying true AF volumes.

Adult↗

PubMed2000

Amniotic fluid volume estimation and the biophysical profile: a confusion of criteria.

The biophysical profile (BPP) can be used as an initial test of fetal health and as a secondary back-up assessment of fetuses at risk of adverse outcomes when preliminary evaluations are not reassuring. The BPP evaluates five characteristics: fetal movement, tone, breathing, heart reactivity, and amniotic fluid (AF) volume estimation. Three of the most frequently used obstetric textbooks define adequate AF volume differently. In two of the three, the stated method of evaluating AF volume differs from that actually used by the referenced authors. We reviewed articles by Manning and found that his methodology changed from a 1-cm pocket in one plane to a 1-cm pocket in two perpendicular planes, and finally to a 2-cm vertical pocket with a 1-cm horizontal measurement. The 2 x 2-cm pocket is a fourth methodology that has been introduced recently. It is not known how often and in which groups each of the four methods has been used to evaluate abnormal AF volumes. The relevance and importance of determining precisely the ultrasound measurement actually used for investigations are emphasized by looking at women with AF indices < or = 5. Fifty-three percent of those women had a 2 x 2 pocket, 72% had a 2 x 1 pocket, and 95% had a 1 x 1 pocket. The diagnosis of low fluid can lead to additional testing, hydration, and intervention, so the importance of a universal definition linked with pregnancy outcomes cannot be overemphasized.

Amniotic Fluid↗

PubMed2000

Cardiopulmonary morbidity as a complication of severe preeclampsia HELLP syndrome.

OBJECTIVE: To profile the types and frequencies of cardiopulmonary morbidity encountered in patients with severe preeclampsia with or without hemolysis, elevated liver enzymes, and low platelets (HELLP syndrome). STUDY DESIGN: We initiated a retrospective study of 979 patients with severe preeclampsia with and without HELLP syndrome. Types of cardiopulmonary morbidity were analyzed among the three classes of HELLP syndrome and severe preeclampsia without HELLP syndrome. RESULTS: Cardiopulmonary morbidity occurred in 7.6% of study patients. As a group, patients with cardiopulmonary complications were more likely to have cesareans (11% vs 6%, p = 0.019) earlier in gestation (1366 +/- 700 gm birth weight versus 1734 +/- 892 gm birth weight, p = 0.021), with higher peak postpartum blood pressures (< 0.001) and with more abnormal laboratory values indicative of multisystem disease, compared with patients without this complication. Patients with cardiopulmonary complications required almost twice as long to achieve diuresis as comparison patients (22 +/- 23 hours versus 12 +/- 11 hours, p < 0.001). CONCLUSION: The probability of cardiopulmonary complications increases significantly when patients develop class 1 HELLP syndrome. Of all cardiopulmonary complications, acute lung injury/acute respiratory distress syndrome is most specific to class 1 HELLP syndrome. Transient renal dysfunction is closely related to cardiopulmonary morbidity.

Cesarean Section↗

PubMed2000

Critical care of HELLP syndrome with corticosteroids.

HELLP syndrome is a special type of severe preeclampsia that constitutes a management dilemma for obstetricians. The high maternal and perinatal morbidity (and rarely maternal mortality) that can result from this entity mandates continuing efforts to find an effective treatment or prevention. The traditional therapy for HELLP syndrome has been meticulous medical care of the mother, vigilant fetal surveillance, and timely delivery. Proposed new therapies to permit prolongation of preterm pregnancy and fetal maturation include vasodilation therapy using fluids and antihypertensives and intensive corticosteroid therapy using intravenously administered high dose dexamethasone, usually in a dose of 10 mg every 12 hours. The latter therapy appears to improve fetal and maternal health with the added benefit of accelerating postpartum recovery from HELLP syndrome.

Anti-Inflammatory Agents↗

PubMed2000

Intrauterine endotoxin infusion in rat pregnancy induces preterm delivery and increases placental prostaglandin F2alpha metabolite levels.

OBJECTIVE: This study was designed to examine the effects of intrauterine endotoxin (lipopolysaccharide) on rat pregnancy. STUDY DESIGN: Pregnant Sprague-Dawley rats (N = 26) were implanted with uterine catheters on day 15 or 16 of a 22-day gestation. Animals were randomly assigned to receive either lipopolysaccharide (25 or 50 microg) or sodium chloride solution (1 mL) on day 17 and then were either sacrificed on day 19 or observed until delivery. Placentas were harvested at the time of death, homogenates were prepared, and prostaglandin F(2)(alpha) metabolite levels were determined by means of radioimmunoassay. Data were analyzed by analysis of variance, Student-Newman-Keuls, and Mann-Whitney tests. RESULTS: Lipopolysaccharide-treated groups (25 and 50 microg) displayed a shorter interval to delivery (mean +/- SE, 82 +/- 13 and 63 +/- 8 hours, respectively) than control animals (117 +/- 3 hours). Pups of lipopolysaccharide-treated (25 and 50 microg) female animals had lower live birth weights (4.92 +/- 0.01 and 5.12 +/- 0. 24 g, respectively) compared with control animals (6.04 +/- 0.07 g). Placental homogenates from lipopolysaccharide-treated female animals contained higher levels of prostaglandin F(2)(alpha) metabolite (1567 +/- 64 and 1475 +/- 59 pg/mL) than those from sodium chloride solution-infused control animals (804 +/- 68 pg/mL). CONCLUSION: Bacterial products induce the preterm delivery of low-birth-weight pups in rats, possibly by increasing local prostaglandin biosynthesis.

Animals↗

PubMed2000

The amniotic fluid index, single deepest pocket, and two-diameter pocket in normal human pregnancy.

OBJECTIVE: This study was undertaken to determine normative values for amniotic fluid index, single deepest pocket, and 2-diameter pocket across gestation. STUDY DESIGN: Fifty patients with normal pregnancies at each gestational age between 14 and 41 weeks' gestation were recruited prospectively and scanned once. Data were transformed into logarithmic (base 10) values for analysis. Polynomial regression equations were used to predict the normal values for amniotic fluid index, single deepest pocket, and 2-diameter pocket across gestational age and to predict the weekly percentage changes. RESULTS: The mean amniotic fluid index, single deepest pocket, and 2-diameter pocket values were significantly lower among patients at <37 weeks' gestation (n = 1150) than among those at > or =37 weeks' gestation (n = 250; P <.001 for all comparisons). The calculated prevalences of oligohydramnios (amniotic fluid index < or =5 cm, single deepest pocket <2 cm, or 2-diameter pocket <15 cm(2)) were significantly different (P <.0001) for the three techniques (8%, 1%, and 30%, respectively). Hydramnios (amniotic fluid index >24 cm, single deepest pocket >8 cm, or 2-diameter pocket >50 cm(2)) was also diagnosed with significantly different (P <.0001) frequencies (0%, 0.7%, and 3%, respectively). CONCLUSIONS: This is the largest prospective study to date to provide normative data for each of three ultrasonographic techniques used to assess amniotic fluid volume. The single deepest pocket appears to be the preferable method, because its use is least likely to lead to the false-positive diagnosis of either oligohydramnios or hydramnios.

Adult↗

PubMed2000

Sustained CD4+ T cell response after virologic failure of protease inhibitor-based regimens in patients with human immunodeficiency virus infection.

The relationship between plasma human immunodeficiency virus (HIV) RNA levels and peripheral CD4+ T cell counts was examined in 380 HIV-infected adults receiving long-term protease inhibitor therapy. Patients experiencing virologic failure (persistent HIV RNA >500 copies RNA/mL) generally had CD4+ T cell counts that remained greater than pretherapy baseline levels, at least through 96 weeks of follow-up. The CD4+ T cell response was directly and independently related to degree of viral suppression below the pretreatment baseline. For any given HIV RNA level measured 12 weeks after virologic failure, subsequent CD4+ T cell decline was slower in patients receiving a protease inhibitor-based regimen than in a historical control group of untreated patients. These observations suggest that transient or partial declines in plasma HIV RNA levels can have sustained effects on CD4+ T cell levels.

Adult↗

PubMed2000

Use of epidemiologically well-defined subjects and existing immunofluorescence assays to calibrate a new enzyme immunoassay for human herpesvirus 8 antibodies.

Agreement between assays for the detection of human herpesvirus 8 (HHV-8) antibodies has been limited. In part, this disagreement has been because assay calibration (i.e., differentiating positive from negative results) has not been done in a standardized fashion with reference to a wide spectrum of HHV-8-infected (true-positive) and HHV-8-uninfected (true-negative) persons. To describe the performance of an assay for HHV-8 antibodies more accurately, we used epidemiologically well-characterized subjects in conjunction with testing on two existing immunofluorescence assays for HHV-8 antibodies to define two groups: a group of 135 HHV-8-infected individuals (true positives), including Kaposi's sarcoma patients and those asymptomatically infected, and a group of 234 individuals with a high likelihood of being HHV-8 uninfected (true negatives). A new enzyme immunoassay (EIA), using lysed HHV-8 virion as the antigen target, was then developed. With the above true positives and true negatives as references, the sensitivity and specificity of the EIA associated with different cutoff values were determined. At the cutoff that maximized both sensitivity and specificity, sensitivity was 94% and specificity was 93%. When the EIA was used to test a separate validation group, a distribution of seropositivity that matched that predicted for the agent of Kaposi's sarcoma was observed: 55% of homosexual men were seropositive, versus 6% seropositivity in a group of children, women, and heterosexual men. It is proposed that the EIA has utility for large-scale use in a number of settings and that the calibration method described can be used for other assays, both to more accurately describe the performance of these assays and to permit more-valid interassay comparison.

Antibodies, Viral↗

PubMed2000

Cesarean delivery for suspected fetal distress among preterm parturients.

OBJECTIVE: Among preterm parturients (< 37 weeks) who underwent cesarean delivery for suspected fetal distress, to determine the factors associated with decision-incision time (DIT) of < or = 30 minutes and to assess if umbilical arterial pH < 7.10 is more common with DIT < or = 30 or > 30 minutes. STUDY DESIGN: The peripartum course of all patients who had cesareans for suspected fetal distress over three years was reviewed. The inclusion criteria were reliable gestational age < 37 weeks and a single indication for cesarean delivery, suspected fetal distress. Twenty antepartum and intrapartum factors were used in a univariate analysis. RESULTS: The mean DIT among the 84 parturients was 30.5 +/- 21.2 minutes, and 63% of patients had surgery started within 30 minutes. The incidence of pH < 7.10 was 20%. Multivariate analysis indicated that the two factors significantly associated with prolonged time to surgery were tachycardia with decreased variability (odds ratio [OR] 5.9, 95% confidence interval [CI] 1.6-21.6) and use of spinal anesthesia (OR 6.2, 95% CI 1.1-35.0). Though none of the 20 variables had significant univariate associations with neonatal acidosis at alpha = .05, those with P < .20 were considered in multiple logistic regression analysis. None of the 20 factors were associated with pH < 7.10, including DIT of > or = 30 minutes (OR 0.26, 95% CI 0.06-1.03). CONCLUSION: DIT is likely to be > 30 minutes if cesarean delivery is due to decreased fetal heart variability or if spinal anesthesia is utilized; neonatal acidosis, however, is not significantly associated with a prolonged interval.

Acidosis↗

PubMed2000

Increasing maternal weight: a risk factor for preeclampsia/eclampsia but apparently not for HELLP syndrome.

BACKGROUND: Maternal obesity is a risk factor for severe preeclampsia. We sought to ascertain whether a similar relationship exists between maternal weight and HELLP syndrome (hemolysis, elevated liver enzymes, and low platelets) as an atypical form of severe preeclampsia. METHODS: In this retrospective investigation, 434 patients with HELLP syndrome were assigned to one of four study groups according to maternal weight and were analyzed in relation to selected maternal and perinatal data reflective of disease severity. RESULTS: We found no significant associations between maternal weight and parameters of HELLP syndrome severity, race, delivery mode, gestational age, or perinatal outcome. Significantly associated with increasing maternal weight were maternal age, parity, admission mean arterial pressure, peak peripartum systolic blood pressures, concurrent essential hypertension, and the interval between admission and delivery. Inversely associated were eclampsia and the interval between delivery and discharge. CONCLUSIONS: Severity and complications attendant with HELLP syndrome appear unrelated to maternal weight. Paradoxically, eclampsia occurs most commonly in the lighter gravida with HELLP syndrome.

Adult↗

PubMed2000

Leukocytosis is proportional to HELLP syndrome severity: evidence for an inflammatory form of preeclampsia.

BACKGROUND: We investigated the possibility that HELLP syndrome is in part a systemic inflammatory response. METHODS: We evaluated total white blood cell (WBC) counts of all patients with severe preeclampsia with and without HELLP syndrome admitted to our hospital between 1995 and 1997. Patients were grouped by diagnosis and timing of platelet nadir. Analysis of variance and regression analysis were used for data analysis. RESULTS: Of 177 patients, 91 had HELLP syndrome, and 86 had severe preeclampsia alone. The WBC counts were significantly higher in patients with HELLP syndrome (12.5 +/- .442 x 10(9)/L) than in patients with severe preeclampsia (10.3 +/- .288 x 10(9)/L). Regression analysis showed that platelet counts varied inversely with WBC counts. Also, patients with class I HELLP syndrome had significantly higher WBC counts than patients with other classes of HELLP syndrome. CONCLUSION: The finding of an association between increasing leukocytosis and worsening thrombocytopenia early in the course of HELLP syndrome supports the hypothesis that it may represent an inflammatory process.

Analysis of Variance↗

PubMed1999

Persistant pre-eclampsia post partum with elevated liver enzymes and hemolytic uremic syndrome.

The spectrum of complications with pre-eclampsia, which may include AFLP (acute fatty liver of pregnancy) as well as the HELLP syndrome (hemolysis, elevated liver enzymes, and low platelets), is resolved by early delivery. However, the ravages of HUS/TTP (hemolytic uremic syndrome/thrombotic thrombocytopenic purpura) require therapy usually by plasma exchange. Overlap between these two groups of syndromes has occurred on rare occasions and usually requires the therapy of the predominant or more dangerous or threatening form. Such overlap can be appreciated and then treated successfully without residual morbidity. The index case is presented and an extensive review of the two groups of syndromes is provided.

Adult↗

PubMed1999

Neonatal sepsis and death caused by resistant Escherichia coli: possible consequences of extended maternal ampicillin administration.

OBJECTIVE: Our goal was to evaluate the relationship between neonatal death caused by sepsis associated with ampicillin-resistant organisms and length of antibiotic exposure. STUDY DESIGN: All neonatal deaths from culture-positive sepsis over a 3-year period were examined. Infants who were delivered at either the University of Mississippi Medical Center or at Saint Barnabas Medical Center at >/=24 weeks' gestation and died within 7 days of life were included. Information on the organism causing sepsis and its sensitivities was collected, and the number of doses of ampicillin administered to the mother before delivery was determined. RESULTS: Of the 78 neonatal deaths, 35 met the inclusion criteria. There were 8 cases of sepsis from ampicillin-resistant Escherichia coli and 27 cases caused by other organisms. There was a statistically significant difference between the mean number of doses of ampicillin received by the ampicillin-resistant Escherichia coli group (17.6 +/- 5.5) compared with the other organisms group (4.9 +/- 3.6) (P <.001). CONCLUSION: A relationship exists between neonatal death caused by ampicillin-resistant Escherichia coli and prolonged antepartum exposure to ampicillin.

Ampicillin↗

PubMed1999

Multiple courses of betamethasone to enhance fetal lung maturation do not suppress neonatal adrenal response.

OBJECTIVE: Our purpose was to evaluate the neonatal adrenal gland by provocative testing in neonates of mothers who had received multiple courses of betamethasone to enhance fetal lung maturity. STUDY DESIGN: Infants of mothers who had received >/=3 courses of betamethasone for fetal lung maturation were enrolled in the study. Twenty-four hours after delivery a baseline serum cortisol concentration was obtained. A synthetic adrenocorticotropic hormone (Cortrosyn) was administered (0.25 mg/1.73 m2). Two hours later a second serum cortisol concentration was obtained. An increase in serum cortisol in response to Cortrosyn was considered a positive test result. Nominal data were compared by means of the Student t test. RESULTS: There were 9 infants enrolled in the study. The mean number of betamethasone treatment cycles was 4.8 +/- 1.09. The mean baseline cortisol level was 2.23 +/- 0.52 microgram/dL, and the mean post-adrenocorticotropic hormone cortisol level was 9.86 +/- 1.70 microgram/dL. All neonates had a positive adrenocorticotropic hormone test result. Stepwise linear regression showed no association between the number of courses of betamethasone treatment cycles and the post-adrenocorticotropic hormone cortisol concentration. CONCLUSION: Multiple weekly treatment cycles of betamethasone for fetal lung maturity administered between 24 and 34 weeks' gestation do not appear to cause adrenal suppression.

Adrenal Glands↗

PubMed1999

The spectrum of severe preeclampsia: comparative analysis by HELLP (hemolysis, elevated liver enzyme levels, and low platelet count) syndrome classification.

OBJECTIVE: This study was undertaken to explore the spectrum of maternal disease with a triple classification system of HELLP (hemolysis, elevated liver enzyme levels, and low platelet count) syndrome and compare these classes with severe preeclampsia without HELLP syndrome. STUDY DESIGN: In this retrospective analytic study the pregnancies of 777 patients with class 1, 2, or 3 HELLP syndrome were compared and contrasted with those of 193 women with severe preeclampsia but without HELLP syndrome. RESULTS: Eclampsia, epigastric pain, nausea and vomiting, significant proteinuria, major maternal morbidity, and stillbirth increased as HELLP syndrome worsened from class 3 to class 1. In contrast, headache and diastolic hypertension were more common among the significantly heavier patients with severe preeclampsia without HELLP syndrome. Approximately half of pregnancies complicated by class 1 HELLP syndrome exhibited significant maternal morbidity, compared with only 11% of those complicated by severe preeclampsia without HELLP syndrome. Although a significant trend was apparent in increasing levels of lactate dehydrogenase, aspartate aminotransferase, and uric acid as HELLP syndrome worsened, there was considerable variation within groups. CONCLUSION: Laboratory and clinical indices of disease severity in patients with severe preeclampsia or eclampsia generally were highest with class 1 HELLP syndrome and were lowest when HELLP syndrome was absent. Class 3 HELLP syndrome is considered a clinically significant transitional group.

Aspartate Aminotransferases↗

PubMed1999

Planned cesarean hysterectomy: A preferred alternative to separate operations.

OBJECTIVE: The aim of this study was to evaluate our institutional experience with planned cesarean hysterectomy. STUDY DESIGN: In this retrospective case-control investigation of a 16-year experience, 100 pregnant women who underwent planned cesarean hysterectomy were compared with 37 patients who underwent cesarean delivery followed by a hysterectomy performed within 6 months. RESULTS: Women undergoing planned cesarean hysterectomy did not have any demonstrable increase in intraoperative or postoperative complications when compared with the cesarean delivery plus later hysterectomy group. Primarily as a result of significantly reduced hospital stay and shorter total operative time, there was a significant financial advantage associated with a single planned cesarean hysterectomy with respect to separate operations. CONCLUSIONS: A policy to undertake planned cesarean hysterectomy for carefully selected patients appeared to produce advantages without increasing risks for these patients. Secondarily, it provided resident physicians the opportunity to learn the operation with supervision and under controlled circumstances.

Adult↗

PubMed1999

Early risk assessment of severe preeclampsia: admission battery of symptoms and laboratory tests to predict likelihood of subsequent significant maternal morbidity.

OBJECTIVE: This study was undertaken to investigate the utility of an admission battery of findings and laboratory data in the discrimination of patients with severe preeclampsia with or without HELLP (hemolysis, elevated liver enzyme levels, and low platelet count) syndrome at high risk for development of significant maternal morbidity. STUDY DESIGN: The clinical and laboratory findings at hospital admission for 970 patients with severe preeclampsia with or without HELLP syndrome were studied retrospectively to develop parameters associated with low, moderate, and high risks for the subsequent development of significant maternal morbidity involving the hematologic and coagulation, cardiopulmonary, and hepatorenal systems. RESULTS: Nausea and vomiting and epigastric pain are independent risk factors for complicated severe preeclampsia. Results of a panel of tests with values including lactate dehydrogenase level >1400 IU/L, aspartate aminotransferase level >150 IU/L, alanine aminotransferase level >100 IU/L, uric acid level >7.8 mg/dL, serum creatinine level >1.0 mg/dL, and 4+ urinary protein by dipstick can be used to discriminate the patient at high risk for significant maternal morbidity. Concentrations of lactate dehydrogenase, aspartate aminotransferase, and uric acid above these cut points have the strongest predictive value and are risk additive with worsening thrombocytopenia. CONCLUSION: The presence of nausea and vomiting, epigastric pain, or both in association with admission laboratory values that are in excess of the cutoffs for lactate dehydrogenase, aspartate aminotransferase, and uric acid concentrations or for all 6 tests is predictive of high risk of morbidity for the patient with severe preeclampsia. These factors are independent of and additive with the rising maternal risk associated with decreasing platelet count.

Alanine Transaminase↗