Human population genetic structure and diversity inferred from polymorphic L1(LINE-1) and Alu insertions.

BACKGROUND/AIMS: The L1 retrotransposable element family is the most successful self-replicating genomic parasite of the human genome. L1 elements drive replication of Alu elements, and both have had far-reaching impacts on the human genome. We use L1 and Alu insertion polymorphisms to analyze human population structure. METHODS: We genotyped 75 recent, polymorphic L1 insertions in 317 individuals from 21 populations in sub-Saharan Africa, East Asia, Europe and the Indian subcontinent. This is the first sample of L1 loci large enough to support detailed population genetic inference. We analyzed these data in parallel with a set of 100 polymorphic Alu insertion loci previously genotyped in the same individuals. RESULTS AND CONCLUSION: The data sets yield congruent results that support the recent African origin model of human ancestry. A genetic clustering algorithm detects clusters of individuals corresponding to continental regions. The number of loci sampled is critical: with fewer than 50 typical loci, structure cannot be reliably discerned in these populations. The inclusion of geographically intermediate populations (from India) reduces the distinctness of clustering. Our results indicate that human genetic variation is neither perfectly correlated with geographic distance (purely clinal) nor independent of distance (purely clustered), but a combination of both: stepped clinal.

Identity by descent and DNA sequence variation of human SINE and LINE elements.

To test the hypothesis that Alu and L1 elements are genetic characters that are essentially homoplasy-free, we sequenced a total of five human L1 elements and eleven recently integrated Alu elements from 160 chromosomes (80 individuals representing four diverse human populations). Analysis of worldwide samples at L1 loci revealed 292 segregating sites and a nucleotide diversity of 0.0050. For Ya5 Alu loci, there were 129 segregating sites and nucleotide diversity was estimated at 0.0045. The Alu and L1 sequence diversity varied element to element. No completely or partially deleted Alu or L1 alleles were identified during the analysis. These data suggest that mobile element insertions are identical by descent characters for the study of human population genetics.

A prospective randomized study of the potential benefits of thoracic epidural anesthesia and analgesia in patients undergoing coronary artery bypass grafting.

We performed an open, prospective, randomized, controlled study of the incidence of major organ complications in 420 patients undergoing routine coronary artery bypass graft surgery with or without thoracic epidural anesthesia and analgesia (TEA). All patients received a standardized general anesthetic. Group TEA received TEA for 96 h. Group GA (general anesthesia) received narcotic analgesia for 72 h. Both groups received supplementary oral analgesia. Twelve patients were excluded-eight in Group TEA and four in Group GA-because of incomplete data collection. New supraventricular arrhythmias occurred in 21 of 206 patients (10.2%) in Group TEA compared with 45 of 202 patients (22.3%) in Group GA (P = 0.0012). Pulmonary function (maximal inspiratory lung volume) was better in Group TEA in a subset of 93 patients (P < 0.0001). Extubation was achieved earlier (P < 0.0001) and with significantly fewer lower respiratory tract infections in Group TEA (TEA = 31 of 206, GA = 59 of 202; P = 0.0007). There were significantly fewer patients with acute confusion (GA = 11 of 202, TEA = 3 of 206; P = 0.031) and acute renal failure (GA = 14 of 202, TEA = 4 of 206; P = 0.016) in the TEA group. The incidence of stroke was insignificantly less in the TEA group (GA = 6 of 202, TEA = 2 of 206; P = 0.17). There were no neurologic complications associated with the use of TEA. We conclude that continuous TEA significantly improves the quality of recovery after coronary artery bypass graft surgery compared with conventional narcotic analgesia.

Characteristics of patients with upper respiratory tract infection presenting to a walk-in clinic.

OBJECTIVE: To profile patients with upper respiratory tract infection (URI) presenting to a walk-in clinic, to quantify their perspectives on the need for antibiotic therapy, and to find out their predictions of future behavior for similar illnesses. PATIENTS AND METHODS: In the spring of 1998, previsit and postvisit questionnaires were distributed at the clinic to patients 18 years of age or older with URI symptoms. RESULTS: Based on 210 completed previsit questionnaires, 161 respondents (77%) had been ill 5 or more days, 200 (95%) had cough, 177 (84%) had phlegm, 132 (63%) had sinus pain, and 79 (38%) had fever. Additionally, 54 patients (26%) reported a history of chronic obstructive pulmonary disease, asthma, or chronic sinusitis, and 37 (18%) were smokers. Most patients were between 18 and 40 years of age. The 210 patients were categorized into 2 groups: those who believed that antibiotics were necessary (157 [75%]) and those who believed antibiotics were unnecessary (53 [25%]). The only statistically significant difference between the 2 groups was in patients with sinus pain: 109 (69%) wanted antibiotics compared with 23 (43%) who did not (P<.001). Of the 210 patients, 130 completed postvisit questionnaires, 129 (99%) of whom reported satisfaction with the clinic visit. All patients who either desired or received antibiotics indicated they would likely seek medical care for future URIs. CONCLUSIONS: The majority of patients with presumed URI presenting to this walk-in clinic expect to receive treatment with antibiotics. Of our 130 study patients, 83 (64%) received antibiotics regardless of their desire for antibiotic treatment. Satisfaction with the office visit was independent of patients' initial beliefs about antibiotics and whether antibiotics were prescribed.

Monitoring women at risk for preterm labor.

BACKGROUND: Preterm birth is a major cause of perinatal morbidity and mortality. Whether the rate of preterm birth can be reduced by frequent contact between nurses and pregnant women or home monitoring of uterine activity is not known. METHODS: We randomly assigned 2422 pregnant women with known risk factors for preterm labor (including 844 women who were pregnant with twins) to receive education and to have one of the following: weekly contact with a nurse, daily contact with a nurse, or daily contact with a nurse and home monitoring of uterine activity. The nurses elicited the women's own assessments of their symptoms and signs of preterm labor. The primary end point was the incidence of birth at less than 35 weeks' gestation. Secondary end points included cervical status at the time preterm labor was diagnosed and birth weight. RESULTS: There were no significant differences among the groups in the incidence of birth at less than 35 weeks (14 percent in the weekly-contact group, 13 percent in the daily-contact group, and 14 percent in the home-monitoring group), in the mean amount of cervical dilatation at the time preterm labor was diagnosed (1.8 cm, 1.5 cm, and 1.4 cm, respectively), or in such neonatal outcomes as birth weights of less than 1500 g or less than 2500 g. However, daily contact with a nurse increased the mean number of unscheduled visits to obstetricians (1.2 in the weekly-contact group, 1.8 in the daily-contact group, and 2.3 in the home-monitoring group) and the proportion of women who received prophylactic tocolytic drugs (12 percent, 14 percent, and 19 percent, respectively). CONCLUSIONS: Women who have daily contact with a nurse, with or without home monitoring of uterine activity, have no better pregnancy outcomes than women who have weekly contact with a nurse.

Thoracic epidural anaesthesia for coronary artery bypass graft surgery. Effects on postoperative complications.

We have performed a retrospective analysis of the peri-operative course of 218 consecutive patients who underwent routine coronary artery bypass graft surgery in this institution. All patients received a standardised general anaesthetic using target-controlled infusions of alfentanil and propofol. One hundred patients also received thoracic epidural anaesthesia with bupivacaine and clonidine, started before surgery and continued for 5 days after surgery. The remaining 118 patients received target-controlled infusion of alfentanil for analgesia for the first 24 h after surgery, followed by intravenous patient-controlled morphine analgesia for a further 48 h. Using computerised patient medical records, we analysed the frequency of respiratory, neurological, renal, gastrointestinal, haematological and cardiovascular complications in these two groups. New arrhythmias requiring treatment occurred in 18% of the thoracic epidural anaesthesia group of patients compared with 32% of the general anaesthesia group (p = 0.02). There was also a trend towards a reduced incidence of respiratory complications in the thoracic epidural anaesthesia group. The time to tracheal extubation was decreased in the epidural group, with the tracheas of 21% of the patients being extubated immediately after surgery compared with 2% in the general anaesthesia group (p < 0.001). There were no serious neurological problems resulting from the use of thoracic epidural analgesia.

Prostaglandin E2 for induction of labor in patients with premature rupture of membranes at term.

OBJECTIVE: A prospective study comparing three management schemes for patients at term with premature rupture of membranes was performed. STUDY DESIGN: One hundred forty patients were randomized to one of three study groups: prostaglandin E2, placebo, or oxytocin. Patients randomized to prostaglandin E2 and placebo received vaginal suppositories containing 3 mg prostaglandin E2 or glycerin only, respectively; suppositories were administered in a double-blind fashion, on one or two occasions, 6 hours apart. Oxytocin was given only if labor was not established after 12 hours or to augment inadequate labor. In patients randomized to oxytocin labor was induced with intravenous oxytocin. The time interval to delivery, delivery outcome, and complications were analyzed. RESULTS: Patients receiving prostaglandin E2 were more likely to be in labor after one suppository and to be delivered without the addition of oxytocin when compared with placebo. The time interval to delivery was shorter with prostaglandin E2 and oxytocin induction versus placebo ("expectant management"). The incidence of maternal infection was lowest in patients with labor induced by prostaglandin E2. Although the overall cesarean section rate was low, there was a trend toward a lower rate with prostaglandin E2 induction. No adverse effects were observed with prostaglandin E2. CONCLUSION: Prostaglandin E2 can be used successfully to induce labor after premature rupture of membranes at term with greater ease of administration when compared with oxytocin.

Prevention of preterm birth in high-risk patients: the role of education and provider contact versus home uterine monitoring.

A total of 394 patients were enrolled in a study to assess the effectiveness of an educational preterm delivery prevention program and to determine whether the addition of home uterine monitoring to the program improved results in patients at high risk of preterm labor. Both the educational program and home uterine monitoring were found to increase the percentage of women with preterm labor who sought care while still favorable for long-term suppression, resulting in a decreased incidence of preterm births and improved outcome when compared with similar high-risk patients who did not participate in these programs. In a randomized, prospective study, addition of home uterine monitoring to the educational program was found to significantly improve outcome in twin gestations but not in singleton gestations. However, the number of singleton pregnancies was too small to rule out possible benefit from home uterine monitoring in that group.

Induction of NADP-dependent malic dehydrogenase activity in brain of singi fish, heteropneustes fossilis (bloch), by 3,5,3?-triiodothyronine.

For elucidation of thyroid hormone-induced responsiveness of fish brain, various doses (0.012, 0.025, 0.05, 0.1, 0.25, 0.5, 1, 2 and 4 ?g/g) of triiodothyronine (T(3)) were injected in Singi fish, Heteropneustes fossilis (Bloch), for 3 consecutive days and the changes in cytosolic NADP-dependent malic enzyme (ME, EC 1.1.1.40) activity in whole brain tissue were determined. Compared to the control, the ME activity increased with lower doses (0.012, 0.025 and 0.05 ?g/g) and decreased with higher doses (1, 2 and 4 ?g/g) of T(3), showing a biphasic nature of thyroid hormone action. The enzyme activity remained unaltered with 0.1, 0.25 and 0.5 ?g of T(3)/g in comparison to the control. Immersion of the fishes in cycloheximide-containing medium (0.5 mg/l) inhibited the T(3) (0.025 ?g/g)-induced rise in ME activity. On the other hand, the NAD-dependent cytosolic malate dehydrogenase (EC 1.1.1.37) activity and the total protein content of brain cytosol remained unaltered with all doses of T(3) used. The thyroid hormone specificity of cytosolic NADP-dependent malic enzyme in fish brain is thus documented.

Nonionic detergents increase the stoichiometry of ligand binding to the rat hepatic galactosyl receptor.

When digitonin is used to expose intracellular galactosyl (Gal) receptors in isolated rat hepatocytes, only about half of the binding activity for 125I-asialoorosomucoid (ASOR) is found as compared to cells solubilized with Triton X-100. The increased ligand binding in the presence of detergent is not due to a decrease in Kd but could be due either to an increase in the number of ASORs bound per receptor or to exposure of additional receptors. Several experiments support the former explanation. No additional activity is exposed even when 80% of the total cell protein is solubilized with 0.4% digitonin. It is, therefore, unlikely that receptors are in intracellular compartments not permeabilized by digitonin and inaccessible to 125I-ASOR. Digitonin-treated cells are not solubilized by Triton X-100 if they are first treated with glutaraldehyde under conditions that retain specific binding activity. 125I-ASOR binding to these permeabilized/fixed cells increases about 2-fold in the presence of Triton X-100 and a variety of other detergents (e.g., Triton X-114, Nonidet P-40, Brij-58, and octyl glucoside) but not with the Tween series, saponin, or other detergents. When these fixed cells are washed to remove detergent, 125I-ASOR binding decreases almost to the initial level. Affinity-purified Gal receptor linked to Sepharose 4B binds approximately twice as much 125I-ASOR in the presence of Triton X-100 as in its absence. The results suggest that the increase in Gal receptor activity in the presence of nonionic detergents is due to an increase in the valency of the receptor rather than to exposure of additional receptors.

Intranuclear degradation of the transformation-inducing protein encoded by avian MC29 virus.

The nuclear protein, p110, encoded by the avian MC29 virus degrades with a half-life of 30 to 40 min in virus-transformed cells. Inhibitors of lysosomal proteolysis had no effect on this degradation. When inhibitors of RNA or protein synthesis were added immediately after pulse-labeling the p110 with [35S]methionine, degradation was impeded. Treatment of cells with cycloheximide prior to, and after, the pulse extended the half-life of p110 further than post-treatment alone, and addition of both actinomycin D and cycloheximide to cells pretreated with cycloheximide extended the half-life even further. In cells depleted of cellular ATP using a glucose-deficient medium containing oligomycin, degradation of p110 was only partially inhibited, indicating no direct involvement of ATP in degradation. Isolation of nuclei or nuclear matrices containing labeled p110, with subsequent incubation, resulted in minimal loss of p110 during several hours. These results suggest that p110 is degraded by a protease which is itself labile and freely diffusible from the nucleus, and, in addition, degradation may involve interaction of p110 with newly synthesized RNA.

The current role of daily serum estriol monitoring in the insulin-dependent pregnant diabetic woman.

This retrospective analysis of the use of serum estriol levels for antenatal assessment was performed in an effort to determine if routine, late third-trimester, daily serum estriol monitoring of insulin-dependent pregnant diabetic women can still be justified. Estriol profiles of 170 diabetic pregnancies, managed under a consistent protocol of weekly contraction stress tests and daily serum estriol assessments, were reviewed. A total of 4612 estriol determinations were performed. Nearly 4% of the estriol determinations showed a 35% fall from the mean of the previous three highest consecutive values. Forty-seven percent of the patients had at least one fall of this magnitude. Eighty-five percent of the fetal heart rate tests performed in association with an estriol fall were normal. A fall in estriol was not found to be associated with a higher risk of having a positive contraction stress test, either at the time the estriol fall was recognized or at any time during the patient's antepartum course. Although use of this strict protocol combining the use of weekly contraction stress tests and daily serum estriol determinations provided a safe method of antepartum assessment, there is little evidence to support the routine use of daily serum estriol monitoring in insulin-dependent pregnant diabetic women.

Maternal herpes infection complicated by prolonged premature rupture of membranes.

Three cases of patients who developed genital herpes virus infections after prolonged, premature rupture of membranes (PROM) at 28-31 weeks gestation are reported. These patients were expectantly managed without immediate intervention at the time of diagnosis of the genital herpes virus infection. In all three cases, there was no evidence of neonatal herpes virus infection at the time of delivery or before hospital discharge. The spectrum of decisions facing the physician managing a patient with prolonged PROM and a genital herpes virus infection is discussed, and a rational approach to management presented.

A new competition assay for the solubilized hepatic galactosyl receptor.

The present method of quantitating soluble asialoglycoprotein (galactosyl) receptor activity relies on the selective precipitation of receptor-ligand complexes to allow separation from free ligand. To provide an alternative to selective precipitation procedures, a simple and rapid method to assay for detergent-solubilized galactosyl receptor activity has been developed which uses permeabilized, fixed cells as a source of immobilized solid-phase receptors. Isolated rat hepatocytes were treated with digitonin to make available the internal as well as the external receptors. The permeable cells were also treated with glutaraldehyde to prevent further protein loss during subsequent exposure to detergents such as Triton X-100. The permeable/fixed cells, which retained about 70% of their total 125I-asialo-orosomucoid (125I-ASOR)-binding activity, with 89% specific binding, were insoluble even in 0.5% Triton X-100 and were easily pelleted. The permeable/fixed cells can be prepared in advance and stored frozen for months. A detergent extract of receptor is mixed with a constant amount of both 125I-ASOR and permeable/fixed cells. Soluble active receptors compete with immobilized receptors on the treated cell for binding of the 125I-ASOR. The assay is reproducible, linear over a broad range of soluble receptor concentration, and can quantitate receptor activity from as few as 10(5) hepatocytes. A modified purification procedure for the rat hepatic galactosyl receptor using this competition assay is also described.

MC29 virus-coded protein occurs as monomers and dimers in transformed cells.

The MC29 virus-coded protein p110gag-myc was found exclusively in the nucleus of transformed Japanese quail (Q8) cells, and time course experiments indicated that the protein had a half-life of about 30 min. When extracts of either Q8 or chicken embryo cells infected with MC29 virus were prepared with nondenaturing detergents and then sedimented in sucrose gradients, p110 was found in the fractions expected to contain monomers (5.9S), dimers (9.3S), or mixtures of the two. The same extracts treated with denaturing detergent (0.2% sodium dodecyl sulfate) exhibited p110 only in fractions expected for the monomeric protein, but beta-mercaptoethanol had no effect on the original distribution. Gradients prepared with 0.5 or 1.0 M NaCl failed to dissociate the faster-sedimenting form. No other protein or polyribonucleotide which could increase the sedimentation rate of p110 was found, and neither RNase nor DNase altered the sedimentation pattern of p110 in nondenatured extracts. A reassociation of monomeric p110 into dimers discernible by gel electrophoresis was demonstrated.

Quantitation of intracellular membrane-bound enzymes and receptors in digitonin-permeabilized cells.

The distribution of membrane-bound receptors and enzymes between the cell surface and the cell interior can be determined without solubilization or gross disruption of cell organelles in the presence of the nonionic detergent digitonin. This steroid glycoside permeabilizes cells, releases cytoplasmic proteins with subunit molecular weights up to 200,000, and allows exogenous molecules to gain access to intracellular receptors. All cell types examined were affected similarly by digitonin. Permeabilization was complete within 2 min at 0 degree C and did not require the continued presence of digitonin. A characteristic amount of protein (approximately 50%) was lost between 0.02 and 0.08% (w/v) digitonin. Three independent systems were examined: the insulin receptor in 3T3 fibroblasts and the asialoglycoprotein receptor and the Na+/K+-ATPase in rat hepatocytes. In each case an increase in the specific activity of enzyme/receptor occurred over a range of detergent concentration in which the retention of cell protein was constant and virtually no solubilization of membrane-bound activity occurred. The binding of 125I-asialo-orosomucoid to rat hepatocytes at 0 degree C in the presence of digitonin was linear with cell number and kinetically indistinguishable from binding to intact cells. Receptors exposed by digitonin were shown to be intracellular by light microscopic examination of permeabilized cells first treated with antiserum to the receptor and then with a second antibody horseradish peroxidase conjugate. The use of digitonin has many advantages over procedures which require total cell disruption or solubilization to assess intracellular receptors. The technique has already been valuable in studies on recycling and endocytosis mediated by the asialoglycoprotein receptor (P.H. Weigel and J.A. Oka (1983) J. Biol. Chem. 258, 5095-5102) and should also be useful in studies with other membrane-bound receptors and enzymes in other cell types.