Patients with chronic obstructive pulmonary disease are at increased risk of death associated with urban particle air pollution: a case-crossover analysis

The authors assessed the acute association between particulate air pollution and mortality among subjects suffering from chronic obstructive pulmonary disease by using a case-crossover analysis. This design avoided the common concerns about the methods used to assess the acute effects of air pollution. The 1,845 men and the 460 women included were residents of Barcelona, Spain, who were over age 35 years, had died during the period 1990-1995, and had visited emergency rooms because of a chronic obstructive pulmonary disease exacerbation during the period 1985-1989. Particle levels (measured as black smoke at the city monitoring stations) were associated with mortality for all causes (odds ratio (OR) for an increase of 20 microg/m3, the interquartile change, adjusted for temperature, humidity, and influenza = 1.112, 95 percent confidence interval (CI): 1.017, 1.215). The association was stronger for respiratory causes (OR = 1.182, 95 percent CI: 1.025, 1.365), but was not significant for cardiovascular causes (OR = 1.077, 95 percent CI: 0.917, 1.264). Older women, patients admitted to intensive care units, and patients with a higher rate of emergency room visits were at greater risk of dying associated with black smoke. The results reinforced the deleterious role of urban pollution and provided information on factors possibly conferring susceptibility to the acute role of air pollution.

Oral support measures used in feeding the preterm infant

BACKGROUND

Evidence that bottle-feeding is a stressor for inefficient preterm infant feeders is seen in untoward changes in the physiologic system and nutritive sucking patterns.

OBJECTIVE

To determine whether a therapeutic technique, oral support (cheek and jaw support), would influence the cardiopulmonary functions or nutritive sucking patterns of preterm infants during feeding.

METHODS

A crossover repeated measures design was used with 20 preterm infants for a total of 40 bottle-feeding sessions. The Whitney Mercury Strain Gage and a Nonin Cardiopulmonary monitor were used to observe sucking characteristics and cardiopulmonary functions during feeding.

RESULTS

Infants not receiving support paused longer (F= 6.37, df= 5, p < .001) and more frequently (F= 5.01, df= 5, p < .001) than supported infants. There were no differences between the groups in the number of sucks and bursts, the burst duration, the stability of the total sucking activity, or the rate of sucking. Oxygen saturation (SaO2) values, heart rate, and respiratory rate did not differ between the groups during feeding. Postfeeding SaO2 levels were lower than prefeeding levels for infants not receiving oral support (t= 0.96, df= 19, p= .03).

CONCLUSION

Oral support provided stability for the jaw and fostered the return of the infant's prefeeding SaO2 values, but it did not interfere with cardiopulmonary function during feeding. Further research is needed to determine whether there is a cumulative effect of oral support, and whether it influences state behavior.

Laparoscopic wedge resection of the gastric wall for gastric benign tumour. The collaboration of the laparoscopic surgeon and the endoscopist

INTRODUCTION

By the introduction of the laparoscopy for the management of gastric pathology many techniques are applied by now. In these techniques the collaboration of the endoscopist and the laparoscopic surgeon is mandatory.

AIMS OF THE STUDY

To emphasise the necessity of the collaboration of the endoscopist and the laparoscopic surgeon for the management of the gastric pathology using the double lifting and wedge resection technique.

METHOD

A case of a female with 2 x 2.5 cm submucosal tumour is presented. The tumour was located in the antrum. After the onset of the general anaesthesia the gastroscope was introduced to locate the position of the tumour, the free edges of the tumour were elevated by a double lifting method and the tumour was resected by a laparoscopic linear stapler. The process of the proper resection was all through observed and directed by the view of the gastroscope.

CONCLUSION

Correct wedge resection of the gastric wall can be safely performed, if the correct gastroscopic control is present. The collaboration of the endoscopist and the laparoscopic surgeon seems to be mandatory, thus avoiding the hazards arising from the use of tattooing.

Abasic site recognition in DNA as a new strategy to potentiate the action of anticancer alkylating drugs?

Inhibition of abasic site repair in the cell seems an attractive strategy to potentiate the action of antitumor DNA alkylating drugs. Molecules that bind specifically and strongly to the abasic site are possible candidates to achieve such inhibition. We explored this strategy by preparing molecule 4 that incorporates (1) an aminoacridine intercalator for DNA binding, (2) an adenine moiety for abasic site recognition, and (3) a linker containing two guanidinium functions to increase binding to DNA without inducing cleavage at the base-sensitive abasic site. Compound 4 was compared to analogues containing secondary amines, i.e., 1. We report on synthesis of the new heterodimer 4. We show by physicochemical studies-including determination of association constants with calf-thymus DNA, T(m) measurements, and high-field NMR examination of the complexes formed with abasic DNA duplexes-that 4 binds specifically and more strongly to the abasic site than the analogues. Compound 4 does not cleave abasic plasmid DNA. Compound 4 shows apparent synergy with the anticancer bischloroethylnitrosourea (BCNU) in L1210 and A549 cell lines in vitro. It potentiates BCNU in the in vivo tests. The results favor the pertinence of the strategy.

Superresolving optical system with time multiplexing and computer decoding

Objects that have slow temporal variations may be superresolved with two moving masks such as pinhole or grating. The first mask is responsible for encoding the input image, and the second one performs the decoding operation. This approach is efficient for exceeding the resolving capability beyond Abbe's limit of resolution. However, the proposed setup requires two physical gratings that should move in a synchronized manner. We propose what is believed to be a novel configuration in which the second grating responsible for the information decoding is replaced with a detector array and some postprocessing digital procedures. In this way the synchronization problem that exists when two gratings are used is simplified. Experimental results are provided for illustrating the utility of the new approach.

Threading bis-intercalation of a macrocyclic bisacridine at abasic sites in DNA: nuclear magnetic resonance and molecular modeling study

The macrocyclic bisacridine (CBA) has been reported previously to specifically recognize single-stranded nucleic acid structures, especially DNA hairpins. The binding of the drug with an abasic site-containing oligonucleotide, was investigated by (1)H NMR and molecular modeling. We have used a DNA undecamer, the d(C(1)G(2)C(3)A(4)C(5)X(6)C(7)A(8)C(9)G(10)C(11)) x d(G(12)C(13)G(14)T(15)G(16)T(17)G(18)T(19)G(2)(0)C(21)G(22)) duplex in which the X residue is a stable analogue of the abasic site [3-hydroxy-2-(hydroxymethyl) tetrahydrofuran]. Analysis of the NMR data reveals that the bisacridine molecule forms two different intercalation complexes in a 80/20 (+/- 10) ratio. For the major complex, a molecular modeling study was performed guided by nineteen intermolecular drug-DNA restraints, determined from NOESY spectra. In this model, the ligand interacts in the threading binding mode with an acridine ring intercalated between the C(7)-A(8) and T(15)-G(16) base pairs, while the other acridine ring resides in the abasic pocket. The two linker chains are positioned in the minor and in the major groove, respectively. A comparable study was performed to evaluate the interaction of CBA with the parent unmodified duplex in which X(6) was replaced by an adenine residue. No complex formation was observed when operating in identical conditions. This shows the selective binding of CBA to the abasic site and its potential interest to target the abasic site lesion.

Experimental and theoretical studies of the conformational perturbations induced by an abasic site

The three-dimensional structure of the natural undecamer duplex d(CGCACACACGC). d(GCGTGTGTGCG) has been determined by the combined use of NMR spectroscopy and restrained molecular dynamics (rMD) and also by molecular mechanics calculations using the JUMNA program without experimental distance constraints. Both procedures have also been used to model the abasic structure d(CGCACOCACGC).d(GCGTGTGTGCG), where 'O' indicates a modified abasic site: 3-hydroxy-2-(hydroxymethyl) tetrahydrofuran. For the natural duplex, 134 interproton distances have been obtained by complete relaxation matrix analysis of the NOESY cross-peaks intensities, using MARDIGRAS software. These distances along with 100 torsion angles for sugar ring and additional data derived from canonical A and B-DNA, have been used for structures refinement by restrained molecular dynamics. Comparison of the natural oligomer with the abasic structure obtained earlier by NMR/rMD (Y. Coppel, N. Berthet, C. Coulombeau, Ce. Coulombeau, J. Garcia and J. Lhomme, Biochemistry 36, 4817-4830, 1997) confirms that the creation of an abasic site, in this sequence context, leads to marked helix kinking. It is also shown that the JUMNA procedure is capable of reproducing the overall structural features of the natural and damaged DNA conformations without the use of experimental constraints.

Serum magnesium concentration is an independent predictor of parathyroid hormone levels in peritoneal dialysis patients

BACKGROUND

Parathyroid hormone (PTH) is a cardinal factor in the pathogenesis of bone disease in the dialysis population. The spectrum of renal osteodystrophy has been reported to have changed during the past years, and adynamic bone disease has emerged as the most common bone disorder in these patients. Continuous ambulatory peritoneal dialysis (CAPD) is considered a risk factor for the development of this condition, and furthermore, the adynamic bone lesion is associated with a state of relative hypoparathyroidism (hypo-PTH). Calcium, vitamin D, and phosphorus play a key role in the control of parathyroid gland function in uremic patients. However, magnesium may also be able to modulate PTH secretion in a way similar to calcium.

OBJECTIVE

The aims of this study were (1) to analyze the serum Mg concentration in a large group of CAPD patients, (2) to study the relationship between serum Mg and PTH levels, and (3) to investigate whether this relationship is independent of other factors, such as calcium, phosphorus, and calcitriol, that regulate parathyroid function.

PATIENTS AND METHODS

We studied 51 stable patients, aged 23-77 years, under maintenance CAPD for more than 6 months (range 8-48 months). Calcium carbonate was used as a phosphate binder in all patients, and 9 subjects also received aluminum hydroxide. No patient had been previously treated with vitamin D. Biochemical parameters were prospectively evaluated over 6 months, and the mean values were computed.

RESULTS

The mean serum Mg was 1.08 +/- 0.19 mmol/L, and hypermagnesemia, defined as a Mg level higher than 1.01 mmol/L, was found in 30 patients (59%). Thirty-one subjects (60%) had an intact PTH (iPTH) level lower than 120 pg/mL and were diagnosed as having relative hypo-PTH. Except for the values of iPTH and alkaline phosphatase, the only difference between the two groups was the serum Mg concentration, which was significantly higher in patients with hypo-PTH (1.16 +/- 0.15 mmol/L vs 0.91 +/- 0.14 mmol/L; p< 0.001). Furthermore, iPTH levels were lower in patients with hypermagnesemia than in subjects with normal serum Mg (69 +/- 49 pg/mL vs 190 +/- 89 pg/mL, p < 0.001). There was a significant correlation between serum Mg and PTH levels (r= -0.70, p< 0.01). After controlling for the effect of other variables by partial correlation analysis, a significant positive association between P and PTH (r= 0.25, p < 0.05), and a negative relationship between Mg and PTH (r= -0.57, p < 0.001) were evident. A forward stepwise multiple regression analysis showed that only P and Mg predicted PTH values (multiple r = 0.59, p < 0.001).

CONCLUSIONS

Hypermagnesemia and hypoparathyroidism are frequent in CAPD patients. There is a significant inverse relationship between serum Mg concentration and iPTH levels. Furthermore, this association is independent of the most important factors regulating parathyroid gland function (calcium, phosphorus, and calcitriol). These results suggest that hypermagnesemia may have a suppressive effect on PTH synthesis and/or secretion. Therefore, elevated serum Mg levels may play a role in the pathogenesis of adynamic bone disease.

Von Willebrand disease as cause of unanticipated bleeding following adeno-tonsillectomy

Von Willebrand disease (vWD) is a frequent autosomal bleeding disorder. We report two unsuspected patients over 6 years of age with this disease operated by tonsillectomy and adenoidectomy (T&A) at our Department. Preoperative hematologic work-up (with activated partial thromboplastic time, prothrombin time, fibrinogen, and platelet count) was normal. Both patients had undergone previous adenoidectomy without complications. In both cases, profuse bleeding was noted in the immediate postoperative period. The therapeutic measures in these situations are discussed and a review of the current literature concerning preoperative hematologic evaluation of T&A is included.

Lemierre's syndrome

Postanginal sepsis, or Lemierre's syndrome, is rare but with life-threatening potential involving mainly infants and adolescents. The morbidity or mortality is caused mainly by lack of knowledge of the syndrome. The 18-year-old boy described here developed a jugular thrombosis 7 days after an angina. Fusobacterium necrophorum was isolated from the culture of the excised jugular vein. Secondary embolism involved the lungs, associated with an iliac osteomyelitis and sacroiliitis. Computed tomography was used for diagnosis and follow-up.

Effect of glycosylation of recombinant human granulocytic colony-stimulating factor on expansion cultures of umbilical cord blood CD34+ cells

BACKGROUND AND OBJECTIVE

Granulocytic colony-stimulating factor (G-CSF) is a cytokine widely used for several purposes such as stem cell mobilization, treatment of neutropenia or in vitro cultures. Recombinant human G-CSF (rh-G-CSF) is available in two forms: a non-glycosylated (E. Coli-derived), and a glycosylated CHO-derived rhG-CSF. As previously shown, glycosylation gives a higher degree of homology between the recombinant and the wild human G-CSF molecule. This study analyses the role of glycosylation in expansion cultures comparing the biological effects of the two forms of G-CSF.

DESIGN AND METHODS

CD34+ cells from nine cord blood samples were positively selected (median purity 84%) and cultured in the presence of 50 ng/mL of stem cell factor and 1, 10 or 100 ng/mL of glycosylated rh-G-CSF (GG) or a deglycosylated form (DG). After 5 days of a static, serum-dependent culture fed on day 0, nucleated cells (NC), CD34+ cells and colony-forming units were evaluated and compared using the paired Student's t-test.

RESULTS

For all concentrations tested, GG was able to generate more NC and progenitors than DG was able to (p<0.05). This effect was mainly observed in CFU-GM colonies, and in CFU-Mix, and indeed no influence was detected in terms of BFU-E expansion. The presence of GG in culture causes the generation of more mature granulocytic cells, assessed by the expression of CD11b/CD15 on CD13+ population, than the presence of DG. In order to check the role of the molecule's stability in this difference, the effect of daily supplementation was tested. Continuous presence of cytokines using either form of G-CSF (daily feeding) significantly increased the rate of expansion, but again GG produced higher generation than its DG counterpart.

INTERPRETATION AND CONCLUSIONS

Our results suggest that the stability of the G-CSF molecule has a predominant effect on the higher biological activity found. A glycosylated form of G-CSF is recommended for in vitro cultures using serum-dependent conditions.

The American Stop Smoking Intervention Study. Conceptual framework and evaluation design

Reducing tobacco use, especially cigarette smoking, is a public health priority. The American Stop Smoking Intervention Study (ASSIST) was initiated in 1991 to prevent and reduce tobacco use primarily through policy-based approaches to alter the social-political environment. This article describes the conceptual design, research framework, evaluation components, and analytic strategies that are guiding the evaluation of this demonstration research endeavor. The ASSIST evaluation is a unique analysis of the complex relationships between the social context, public health activity at the state level, tobacco use, and individual behavior. The measures of tobacco control activity developed for this evaluation may be useful in ongoing national cancer control surveillance efforts, and the lessons learned will enhance the development of tobacco control programs.

A survey of women's experiences of vaginal loss from 24 hours to three months after childbirth (the BLiPP study)

OBJECTIVE

To describe the range of normal vaginal loss as reported by women from 24 hours after delivery until three months postnatally.

SETTING

Two health districts in the south of England.

METHODS

A prospective survey of women's experiences and expectations of the duration, amount and colour of vaginal loss after childbirth. The term vaginal loss includes all types of fluid loss from the vagina following childbirth.

FINDINGS

Five hundred and twenty-four women were recruited to the survey in 1995. Vaginal loss, as reported by the women, was considerably more varied in duration, amount and colour than descriptions in current midwifery textbooks. The median number of days reported for the duration of vaginal loss was 21 days and the interdecile range (10th to 90th percentile) was 10-42 days. For colour of lochia, women overall reported their vaginal loss to be more predominantly red/brown in colour and the traditional descriptions of the timing and colour phases of lochia rubra, serosa and alba are not supported by the majority of the women's experiences. Primiparous women were significantly more likely to report feelings of surprise or shock about their experiences of vaginal blood loss after the birth (odds ratio 4 [95% Confidence Interval 2-9]). Seven primiparous women (2%) were unaware that they would have a blood loss at all after the birth.

IMPLICATIONS FOR PRACTICE

The findings from this survey have been used to develop information leaflets for women and health professionals about vaginal loss following childbirth. These leaflets include descriptions of normal ranges for the colour, amount and duration of vaginal loss in the first three months after childbirth.

Partial transient osteoporosis of the hand

OBJECTIVE

To describe the radiographic and scintigraphic findings of partial transient osteoporosis (PTO) of the hand. To discuss the relationship of PTO and other localized demineralizing diseases.

DESIGN AND PATIENTS

Three patients with PTO that affected two or three digits of the hand are reported. Two patients were middle-aged women and the third was a young man. All presented with a history of trauma to the hand. All patients experienced localized burning pain, swelling and vasomotor changes including redness of the skin, hyperhidrosis and signs of vasomotor instability of the involved fingers. Plain radiography and bone scanning were used in the diagnosis and follow-up of these cases.

RESULTS

All patients had a radial distribution of the osteoporosis that involved adjacent rays. In all patients two rays were involved. The radiographic changes manifested as minimal patchy osteoporosis involving the cortical, cancellous, subarticular and subperiosteal bone with no articular involvement. The increased uptake on scintigraphy coincided with the radial distribution of the osteoporosis. All patients improved on physical therapy and were symptom-free approximately 6 months after the initial injury. These patients were followed up for more than 2 years.

CONCLUSION

PTO of the hand is an uncommon disease with typical clinical and radiographic findings. Bone scintigraphy confirms the partial involvement of the hand.

Feasibility of ESHAP + G-CSF as peripheral blood hematopoietic progenitor cell mobilisation regimen in resistant and relapsed lymphoma: a single-center study of 22 patients

The purpose was study the feasibility of ESHAP + G-CSF for peripheral blood hematopoietic progenitor cell (PBPC) mobilisation in resistant/relapsed Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL). Twenty-two consecutive patients with HD (8) and N-HL (14) received ESHAP chemotherapy and G-CSF (5 microg/Kg/d). When a minimum number of 10,000 peripheral blood CD34+ cells/mL was observed patients underwent leukapheresis until a CD34+ cell dose > or = 2.5x10(6)/Kg was collected or the PBPC peak was lost. Blood cells kinetics and toxicity were analysed. Data concerning the day of first apheresis, number of procedures per patient, and cellular yield of the aphereses were recorded. Correlation between the CD34+ cell content in the apheresis product and the two diagnosis groups was attempted. Twelve patients (54%) developed short-lived severe neutropenia (<0.5x10(9)/L). Thrombocytopenia (<25x10(9)/L) had a median duration of 1 day. Fever appeared in 4 patients and CN Staph bacteriemia in 2 cases. Bleeding events did not supervene and no deaths occurred. Aphereses started at day +15 (median) and the median number of apheresis/patient was 2. Seventeen patients underwent 1 or 2 leukaphereses. Thirteen patients (59%) achieved the CD34+ cell target in the first apheresis. NHL patients obtained statistically significant better CD34+ cell collections than HD. Only 2 HD patients failed to mobilise, 1 previously treated with high-dose therapy and autologous bone marrow transplantation. ESHAP + G-CSF has been shown to be feasible for PBPC mobilisation in resistant/relapsed lymphoma. Toxicity was low and CD34+ cell yield high, especially in N-HL. This mobilisation regimen should be further explored in a larger patient population.

Immunogenicity of 2 serogroup B outer-membrane protein meningococcal vaccines: a randomized controlled trial in Chile

CONTEXT

Meningococcal disease occurs worldwide, and serogroup B disease accounts for a large proportion of cases. Although persons younger than 4 years are at greatest risk for serogroup B meningococcal disease, vaccine efficacy has not been demonstrated in this age group.

OBJECTIVE

To evaluate serum bactericidal activity (SBA) against homologous vaccine type strains and a heterologous Chilean epidemic strain of Neisseria meningitidis as a potential correlate for vaccine efficacy.

DESIGN

Double-blind, randomized controlled trial conducted between March 14 and July 20, 1994. All blood samples were taken by December 1994.

SETTING

Santiago, Chile, where a clonal serogroup B meningococcal disease epidemic began in 1993.

PARTICIPANTS

Infants younger than 1 year (n = 187), children aged 2 to 4 years (n = 183), and adults aged 17 to 30 years (n = 173).

INTERVENTION

Participants received 3 doses of outer-membrane protein (OMP) meningococcal vaccine developed in either Cuba or Norway or a control vaccine, with each dose given 2 months apart. Blood samples were obtained at baseline, prior to dose 3, and at 4 to 6 weeks after dose 3.

MAIN OUTCOME MEASURE

Immune response, defined as a 4-fold or greater rise in SBA titer 4 to 6 weeks after dose 3 compared with prevaccination titer.

RESULTS

Children and adult recipients of either meningococcal vaccine were more likely than controls to develop an immune response to the heterologous epidemic strain. After 3 doses of vaccine, 31% to 35% of children responded to the vaccine vs 5% to placebo; 37% to 60% of adults responded to vaccine vs 4% to placebo (P<.05 vs control for all). Infants, however, did not respond. In contrast, against homologous vaccine type strains, the response rate was 67% or higher among children and adults and 90% or higher among infants (P<.001 vs control for all). Subsequent SBA against 7 isogenic homologous target strains identified class 1 OMP as the immunodominant antigen.

CONCLUSIONS

These data suggest that neither serogroup B OMP meningococcal vaccine would confer protection during a heterologous epidemic. However, epidemic strain-specific vaccines homologous for class 1 OMP are promising candidates for the control of epidemic serogroup B meningococcal disease.

A novel strategy affords high-yield coupling of antibody to extremities of liposomal surface-grafted PEG chains

Several methodologies for the preparation of polyethylene glycol-grafted immunoliposomes have been developed by attaching antibodies to the terminus of the polymer. Unilamellar liposomes were prepared containing a combination of a functionalized polyethylene glycol(3400) and an inert polyethylene glycol(2000) phosphatidylethanolamine derivate up to 5 mol%. The greater length of the functionalized polyethylene glycol derivate did not alter the liposomal sterical stability or the remote loading of doxorubicin. Anti-CD34 immunoliposomes were prepared by the reaction of maleimide-derivatized My10 antibody with generated thiol groups at the periphery of the liposomes and efficiencies of nearly 100% were obtained. The greater accessibility of the reactive group makes this strategy more efficient than others described. The immunoliposomes prepared bound specifically to CD34+ cells.

Biochemical characterization of CD1d expression in the absence of beta2-microglobulin

CD1d is a major histocompatibility complex class I-like molecule that exhibits a distinct antigen processing pathway that functions in the presentation of hydrophobic antigens to T cells. CD1d has been previously shown to be expressed on the cell surface of human intestinal epithelial cell lines in vivo and a transfected cell line in vitro independently of beta2-microglobulin (beta2m). To define the relationship between CD1d and beta2m and characterize the biochemical structure of CD1d in the absence of beta2m, we have used a newly generated series of CD1d transfectants and CD1d-specific antibodies. These studies show that in the absence of beta2m, CD1d is expressed on the cell surface as a 45-kDa glycoprotein that is sensitive to endoglycosidase-H and is reduced to 37-kDa after N-glycanase digestion. In contrast, in the presence of beta2m, CD1d is expressed on the cell surface as a 48-kDa endoglycosidase-H-resistant glycoprotein. Pulse-chase metabolic labeling studies demonstrate that acquisition of endoglycosidase-H resistance of CD1d is observed in the presence of beta2m but not in the absence of beta2m even after a 24-h chase period. Thus, CD1d is able to be transported to the cell surface independently of beta2m; however, in the absence of beta2m, the glycosylation pattern of CD1d is altered and consistent with an immature glycoprotein.

Zelen randomization: attitudes of parents participating in a neonatal clinical trial

Recruitment to randomized controlled trials can be difficult for all parties involved. An alternative to the standard process has been suggested for trials in which the control group receives standard treatment or nontreatment. In this approach (the Zelen design), randomization precedes consent, which is only sought from those allocated to the experimental arm of a trial. The control group is thus unaware that randomization has taken place. As a controversial method, this approach has been often suggested but rarely used. Here we describe how 44 parents recruited to a difficult neonatal trial that used conventional randomization reacted to the idea of Zelen randomization. The arguments they gave for and against the method pertain to four areas: the giving or withholding of information, the effect on decision making, the use of data without parental knowledge, and the long-term impact for parents. The parents were evenly divided in accepting or rejecting the method. Further analysis showed that those rejecting Zelen randomization were more likely to be parents of infants allocated to the control group. This suggests that those from whom consent would not be sought, the group that this approach is primarily meant to protect, are most likely to find it unacceptable.

2'-deoxyribonolactone lesion in DNA: refined solution structure determined by nuclear magnetic resonance and molecular modeling

The solution conformation of the DNA duplex d(C1G2C3A4C5L6C7A8C9G10C11).d(G12C13G14T15G16T17G18T19G20C21G22 ) containing the 2'-deoxyribonolactone lesion (L6) in the middle of the sequence has been investigated by NMR spectroscopy and restrained molecular dynamics calculations. Interproton distances have been obtained by complete relaxation matrix analysis of the NOESY cross-peak intensities. These distances, along with torsion angles for sugar rings and additional data derived from canonical A- and B-DNA, have been used for structure refinement by restrained molecular dynamics (rMD). Six rMD simulations have been carried out starting from both regular A- and B-DNA forms. The pairwise rms deviations calculated for each refined structure are <1 A, indicating convergence to essentially the same geometry. The accuracy of the rMD structures has been assessed by complete relaxation matrix back-calculation. The average sixth-root residual index (Rx = 0.052 +/- 0.003) indicated that a good fit between experimental and calculated NOESY spectra has been achieved. Detailed analysis revealed a right-handed DNA conformation for the duplex in which both the T17 nucleotide opposite the abasic site and the lactone ring are located inside the helix. No kinking is observed for this molecule, even at the abasic site step. This structure is compared to that of the oligonucleotide with the identical sequence containing the stable tetrahydrofuran abasic site analogue that we reported previously [Coppel, Y., Berthet, N., Coulombeau, C., Coulombeau, Ce., Garcia, J., and Lhomme, J. (1997) Biochemistry 36, 4817-4830].

Distribution of genital tract trauma in childbirth and related postnatal pain

BACKGROUND

The full extent of genital tract trauma in spontaneous births is not well documented. The purpose of this study was to describe the range and extent of childbirth trauma and related postnatal pain using data from a large randomized clinical trial of perineal management techniques (n = 5471).

METHODS

Descriptive analysis was conducted on trial participants who delivered spontaneously at term and were examined by their midwife after birth (n = 5404). Data are reported for sites of trauma, and the relation to episiotomy, suturing, and maternal reports of pain at 2 days, 10 days, and 3 months after birth.

RESULTS

Eighty-five percent of all women experienced some form of trauma, with first- or second-degree perineal lacerations occurring in two-thirds of women and outer vaginal tears occurring in one-half. Tears to the rectum and vaginal vault were more common with episiotomy. Nearly all unsutured trauma was restricted to perineal first- or second-degree, outer vaginal, and labial sites. Pain declined over time, and a gradient in pain was observed according to the site and complexity of trauma.

CONCLUSIONS

Genital tract trauma is extremely common with spontaneous vaginal birth. Effective measures to prevent or reduce its occurrence would benefit many new mothers.