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Biomedical subjects

P Simon

Publications and source records attributed to P Simon.

At least 73 records · Page 4Linked to original sources
PubMed2001

Growth of the pulmonary autograft after the Ross operation in childhood.

OBJECTIVE: Excellent hemodynamic performance has been demonstrated after aortic valve replacement using the autologous pulmonary valve as described by D. Ross. However, in the pediatric population there is concern in regard to growth of the autograft and late dilatation in the systemic circulation. METHODS: Since 1991, 30 children (mean age, 11.3+/-3.1 years) had aortic valve replacement with the pulmonary autograft as a root replacement. All children had yearly clinical and echocardiographic follow-up. RESULTS: There were no perioperative deaths; one child died late in a car accident. At the last follow-up (mean follow-up, 4.3+/-2.6 years), all patients were in NYHA class I. There was one early reoperation, in which the autograft had to be reconstructed due to a leaflet perforation. There were no major valve related events. All children showed normal somatic growth. The annulus diameter increased significantly from 18+/-2 at surgery to 20+/-3.5 mm at the latest follow-up (P<0.004). The sinus also increased significantly in diameter from 29+/-4 at surgery to 34+/-2 mm at the last follow-up (P<0.001). This increase in autograft size, both for the annulus and the sinus, paralleled the increase in body surface area with no evidence for unproportional dilatation. Hemodynamic measurements demonstrated physiological peak gradients of 6.8+/-2.9 mmHg and no or trivial aortic insufficiency in 95% of this rapidly growing patient population. CONCLUSION: These data demonstrate growth of the pulmonary autograft parallel to somatic growth without undue dilatation in the systemic circulation. The hemodynamics are excellent with regard to physiological gradients and no increase in aortic insufficiency.

Adolescent↗
PubMed2001

Impact of surgical resection of rectovaginal pouch of douglas endometriotic nodules on pelvic pain and some elements of patients' sex life.

STUDY OBJECTIVE: To assess the impact of laparoscopic resection of endometriotic nodules in the rectovaginal pouch of Douglas on women's pain symptoms, analgesic intake, work absenteeism, work difficulties, and some elements of sex life. DESIGN: Observational study (Canadian Task Force classification II-2). SETTING: Gynecology department at a university hospital. PATIENTS: Twenty-six women with rectovaginal pouch of Douglas endometriotic nodules and no evidence of other potential cause of pain at physical examination, laparoscopy, and transvaginal ultrasonography. INTERVENTION: Laparoscopic resection of endometriotic nodules with the CO2 laser until no residual induration was felt in surrounding tissues. MEASUREMENTS AND MAIN RESULTS: Significant statistical differences were found between preoperative and postoperative pain scores, percentages of women absent from work, percentages taking analgesics or nonsteroidal antiinflammatory drugs, and percentages having work difficulties due to pain. A significant difference also was found in frequencies of sexual desire and coitus. CONCLUSION: Endometriotic nodules in the rectovaginal pouch of Douglas may be responsible for major pelvic pain and also for sexual dysfunction (lack of sexual desire, dyspareunia). Laparoscopic resection of the nodules significantly improves these conditions. (J Am Assoc Gynecol Laparosc 8(1):55-60, 2001)

Adult↗
PubMed2001

The syringaldazine-oxidizing peroxidase PXP 3-4 from poplar xylem: cDNA isolation, characterization and expression.

The cell wall polymer lignin is believed to be condensed by specific cell wall-localized oxidoreductases. In many plants species, including poplar, the peroxidase-directed oxidation of the lignin analogue syringaldazine (SYR) has been localized to cells that undergo secondary wall formation, a process that includes lignification. As a first step to analyse the corresponding peroxidases. we have isolated previously two anionic isoenzymes (PXP 3-4 and PXP 5) from poplar xylem (Populus trichocarpa), which use SYR as a substrate. Here, we demonstrate that these enzymes are responsible for the visualized SYR oxidation in the developing xylem. The cDNA that corresponds to PXP 3-4 was isolated and the deduced protein was found closely related to the other SYR-oxidizing peroxidase PXP 5 (ca. 98% of identity). PXP 3-4 was expressed in a baculovirus expression system yielding high levels of active peroxidase (3 mg/l medium). The heterologously produced protein showed characteristics similar to those of the corresponding protein from poplar xylem (enzymatic properties, isoelectric point, and migration in a native gel). PXP 3-4 was expressed in the stem and in the root xylem. The data demonstrate that PXP 3-4 (and/or PXP 5) are present in differentiating xylem. supporting a function in secondary cell wall formation.

Amino Acid Sequence↗
PubMed2001

An analysis of the immunization status of preschool children enrolled in a statewide Medicaid managed care program.

OBJECTIVES: To measure immunization coverage rates for children enrolled in a statewide Medicaid managed care program and determine the impact of sociodemographic characteristics and the type of primary care provider site on immunization coverage. STUDY DESIGN: A random sample of 2000 was chosen from children between the ages of 19 and 35 months who had been continuously enrolled in the Medicaid managed care program for 1 year. Sociodemographic data and a list of primary care providers for the study children were obtained from administrative databases. Immunization histories were determined by medical record review. RESULTS: Vaccine-specific immunization rates for diphtheria-tetanus-pertussis, polio, Haemophilus influenzae type b, hepatitis B, and measles-mumps-rubella ranged from 87% to 94%, with an overall coverage rate of 75%. Overall immunization status varied by primary care provider site as follows: office-based, 72%; community health center, 75%; hospital-based clinic, 79%; and staff model health maintenance organization, 85% (chi(2) test, P =.008). CONCLUSIONS: Immunization rates compare favorably with national rates for this low-income group. Sociodemographic characteristics were not important predictors of underimmunization, but rates did vary by the type of primary care provider site.

Child Health Services↗
PubMed2001

Detection of macrophage migration inhibitory factor (MIF) in human cholesteatomas and functional implications of correlations to recurrence status and to expression of matrix metalloproteinases-3/9, retinoic acid receptor-beta, and anti-apoptotic galectin-3.

OBJECTIVES: To investigate whether the expression of the macrophage migration inhibitory factor (MIF) 1) is detectable, 2) changes in relation to recurrence and infection status, and 3) relates to the levels of expression of growth regulators/differentiation markers, including galectin-1, -3, and -8, retinoid acid receptors (RAR)]-alpha, -beta, and -gamma, binding sites for sarcolectin, and invasion markers (cathepsins -B and -D, and matrix metalloproteinases [MMP]-2, -3, and -9) in human cholesteatomas. STUDY DESIGN: An analysis of 56 cholesteatomas resected by the same surgeon using canal wall up and canal wall down surgical procedures. METHODS: The immunohistochemical levels of expression of MIF and the proteases were quantitatively determined (using computer-assisted microscopy) on routine histologic slides by specific antibodies, and statistically correlated to parameters of the other markers determined previously in conjunction with data on apoptosis/proliferation. RESULTS: MIF expression was detected. It was significantly higher in the epithelium (P =.002) and vessels (P =.04) of the connective tissues (but not in the connective tissue itself) of recurrent as opposed to non-recurrent cholesteatomas. The MIF expression is significantly correlated (P =.006) to the RAR beta expression in non-infected cholesteatomas, and to MMP-3 (P <.01) and anti-apoptotic galectin-3 (P =.01) in infected cholesteatomas. The level of MIF expression was also correlated significantly to MMP-9 (P = 0.003), RAR beta (P <.001), and galectin-8 (P =.003) expression in the cholesteatomas regardless of their infection status. CONCLUSIONS: MIF expression in human cholesteatomas is related to the levels of biologic aggressiveness reflected in their recurrence status and MMP expression, and to the differentiation status reflected in their galactin and RAR beta expressions. Together with galectin-3, it could cooperate to form an anti-apoptotic feedback loop.

Adolescent↗
PubMed2001

Identification of a Ca(2+)-pectate binding site on an apoplastic peroxidase.

An apoplastic isoperoxidase from zucchini (APRX) was shown to bind strongly to polygalacturonic acid in their Ca(2)+-induced conformation. By homology modeling, we were able to identify a motif of four clustered arginines (positions 117, 262, 268, and 271) that could be responsible for this binding. To verify the role of these arginine residues in the binding process, we prepared three mutants of APRX (M1, R117S; M2, R262Q/R268S; and M3, R262Q/R268S/R271Q). APRX and the three mutants were expressed as recombinant glycoproteins by the baculovirus-insect cell system. This procedure yielded four active enzymes with similar molecular masses that were tested for their ability to bind Ca(2)+-pectate. Recombinant wild-type APRX exhibited an affinity for the pectic structure comparable to that of the native plant isoperoxidase. The mutations impaired binding depending on the number of arginine residues that were replaced. M1 and M2 showed intermediate affinities, whereas M3 did not bind at all. This was demonstrated using an in vitro binding test and on cell walls of hypocotyl cross-sections. It can be concluded that APRX bears a Ca(2)+-pectate binding site formed by four clustered arginines. This site could ensure that APRX is properly positioned in cell walls, using unesterified domains of pectins as a scaffold.

Arginine↗
PubMed2001

Points to consider for ethics committees in human gene therapy trials.

Recent political developments and disclosures of serious adverse events in human gene therapy (HGT) with the death of 18-year old Jesse Gelsinger in the USA have shown that the clinical application of HGT raises some severe ethical issues. These have either been neglected or not yet been discussed to a satisfactory extent. In this paper, we will address this deficiency and develop strategies for a safer application of HGT. Such a study must first look closely at the science of HGT itself. We will evaluate the latest preclinical research, especially data on the viruses that are used as vectors and on modes of administration of vectors. We will put forward new arguments concerning the toxicity assessment of so-called 'gene drugs', the tissue and cell type specificity of the vectors, and the duration and on-set of gene expression. Secondly, we will look at procedural aspects of applied research ethics on the way to clinical application of HGT. There, informed consent (IC) and the patient-researcher relationship are of utmost concern. Furthermore, we will explore the problem of expertise in risk assessment and will show how current regulations foster conflicts on interests that create dilemma situations even for those researchers who act in the best interest of the patients. We will conclude the article with a set of questions for ethicists who have to decide about the quality of HGT protocols. This may contribute to the safety of patients participating in HGT trials and to achieving the aim of efficient application of HGT.

Clinical Trials as Topic↗
PubMed2001

Acute and chronic pancreatitis in patients with inborn errors of metabolism.

Acute and chronic recurrent pancreatitis have been reported in patients with a variety of inborn errors of metabolism. Among these are hyperlipidaemias, various disorders of branched-chain amino acid degradation, homocystinuria, haemolytic disorders, acute intermittent porphyria and several amino acid transporter defects. Some of these disease entities are exceedingly rare. In most of these disorders, pancreatitis is not very common and, with the exception of lipoprotein lipase and apolipoprotein C-II deficiency, is neither the leading nor the clinically most distressing manifestation of the underlying metabolic defect. The majority of these syndromes are, however, inherited, and often entire kindreds are carriers of well-defined germline mutations that can, to varying degrees, be associated with pancreatitis. We have reviewed the clinical, biochemical and genetic characteristics of those inborn errors of metabolism because interesting information can be gained from the in regard to the pathophysiology of pancreatitis and because they need to be distinguished from other hereditary causes of the disease.

Acute Disease↗
PubMed2001

A statewide assessment of lead screening histories of preschool children enrolled in a Medicaid managed care program.

OBJECTIVES: Despite the prominence of lead poisoning as a public health problem, recent Government Accounting Office reports indicate that only one fifth of children who are covered by Medicaid have been screened for lead poisoning. The purpose of this study was to examine the lead screening histories of children who were enrolled in a statewide, Medicaid managed care plan to determine the relative impact of the type of primary care provider site and family sociodemographic characteristics on the likelihood of being screened. The study also examined the prevalence of and risk factors for lead poisoning of children who had been screened. METHODS: A random sample of 2000 preschool-age children was chosen from those who were enrolled continuously in the statewide, expanded, Medicaid managed care program for a 1-year period and between the ages of 19 and 35 months at the end of that year. Sociodemographic characteristics and lists of primary care providers were obtained from administrative data sets. Medical record audits at primary care provider sites were performed to obtain the lead screening histories of the children, including test dates and results. RESULTS: Data on 1988 children were used for study analyses, and 80% of these children had at least 1 documented blood lead level. Children whose primary care provider was an office-based physician were less likely to be screened as compared with patients of health centers, hospital-based clinics, and staff model health maintenance organizations (68%, 86%, 89%, and 91% respectively). Variation in screening rates persisted in a multivariate analysis controlling for family sociodemographic characteristics and practice level variation. Of the 1587 children who had a documented blood lead test, 467 children (29%) had a blood lead level of >/=10 mg/dL on at least 1 test. CONCLUSIONS: Blood lead screening rates in Rhode Island's Medicaid managed care program are dramatically higher than national estimates for children who are enrolled in Medicaid. Potential explanations for this finding are 1) a high sensitization to the problem of lead poisoning in Rhode Island, 2) the primary care focus of the Medicaid program in Rhode Island facilitates the delivery of preventive services, and 3) the medical record audit approach used in this study was more comprehensive in identifying blood lead screens than techniques used in national studies. The high prevalence of elevated blood lead levels found in this study emphasizes the importance of screening among children who are enrolled in Medicaid.

Child, Preschool↗
PubMed2001

[Choroidal neovascularization as a complication following laser treatment of central serous chorioretinopathy].

We report the case of a 39-year old man who presented with central serous chorioretinopathy. Two months after diagnosis, argon laser photocoagulation was performed. One month later, the patient noticed distortion and a reduction in vision revealing a subretinal neovascularization above the fovea next to the laser scar. The patient underwent surgical extraction of the neovascular membrane and recovered a visual acuity of 20/30. This case report shows a complication of laser treatment of central serous chorioretinopathy and underlines the diagnostic difficulties of this disease and its treatment modalities. The surgical excision, the first reported in this etiology, led to good visual recovery, as is usually observed in young patients operated on for neovascular membrane.

Adult↗
PubMed2001

[Conjunctival epithelial carcinoma in a 9-year-old child with xeroderma pigmentosum. Case report].

We report the case of a conjunctival tumor in a 9-year-old patient, suffering from Xeroderma Pigmentosum. Our patient presented a raspberry-colored conjunctival tumor. The tumor was resecked without any additional treatment. The histological study revealed squamous cell carcinoma. A suspicion of relapse appeared two months later of the same location and a new resection was performed. The initial checkup of this tumor was negative. In this disease, ocular localizations are frequent. The conjunctiva, the cornea, the eyelids and, into a lesser extent, the orbit can be involved. Basal cell carcinoma and squamous cell carcinoma are the most frequent tumors observed in Xeroderma Pigmentosum. Their treatment is mainly surgical.

Carcinoma, Squamous Cell↗
PubMed2001

[A new approach in techniques to treat urinary incontinence: TVT (tension free vaginal tape)].

The indications and the surgical technique of a newly developed operation for the correction of female urinary incontinence (the Tension free Vaginal Tape) are described. This technique is based on a new etiological concept of urinary incontinence and ensures the patient a reduced morbidity (local or regional anaesthesia) and hospital stay (theoretically adapted for a one day clinic). Mid-term results (84% success rate after a median follow up of 3 years) are promising but must be confirmed at the long term. We relate our experience of 30 cases with a success rate of 93% but entached with a high rate of postoperatory urinary urgency. This leads us to emphasise a strict adherence to the indications and an absolute respect of the technique as originally described.

Adult↗
PubMed2001

[Straight femoral taper in cementless primary total hip replacement in less than 65 year-old patients: multicenter study of 115 consecutive implantations at mean 8,2 year follow-up].

PURPOSE OF THE STUDY: The Swedish Arthroplasty Registry experience with cemented primary total hip arthroplasty (THA) has pointed out age below 65 and high activity level as 2 major factors impairing THA long-term outcome. The aim of this study was to provide intermediate results of cementless femoral replacement in primary THA with use of the Alloclassic-SL grit-blasted titanium stem in "high risk" groups of patients. MATERIAL AND METHODS: From June, 1988 to June, 1992, 127 cementless primary THA's were consecutively performed in<65 year old patients in 2 institutions. Acetabular components were all cementless (threaded cup in 74%) and bearing surfaces were all alumina-ceramic 28mm heads on polyethylene (PE). Five patients (6 hips) died and 6 other hips were lost to follow-up before the 5-year minimum follow-up. Thus, 115 hips in 106 patients could be fully reviewed after a 8.2 year average follow-up period (range, 5 to 12 years). Mean age at surgery of the 62 male and 44 female patients was 52 years (range, 27 to 65 years). RESULTS: Of the index group (127 hips), intra-operative fracture of the greater trochanter and early dislocation were noted in 4.7% and 3.2% of hips, respectively. Of the study group (115 hips), clinical results according to the Merle d'Aubigné and Charnley rating system were graded excellent and good in 94% of hips and fair in 6% (7 hips), with no poor result. Radiologically, early subsidence of more than 2mm could be detected in 8 hips (7%). Calcar atrophy and spot welds were noted in 81% and 89% of hips, respectively. Proximal reactive and lucent lines and mild proximal stress shielding were observed in 10.5% and 4.3% of hips, respectively. Ten-year survivorship with stem revision for any reason as the end point was 99.2% (92.4-99.9) (1 stem exchanged and reoriented for immediate dislocation). One revision is pending for extensive femoral osteolysis due to polyethylene (PE) wear. There was no stem fracture and no ceramic head breakage thus far. Overall PE-wear rate ranging 1-2 mm was detected in 13 hips (9.6%) and femoral osteolysis in 4 hips (3.5%). DISCUSSION: Mid-term results of this cementless straight taper at 10 year are at least equal to those of well performing cemented components, even in "high risk" groups of patients. Conversely, 28mm alumina-ceramic heads can reduce but not prevent the occurrence of PE-wear in such a healthy and active population. CONCLUSION: Press-fitting but not filling the femoral canal with rough titanium straight tapers like the Alloclassic-SL femoral component represent a promising alternative to modern femoral cementing technique in primary THA. Improvement is expected through the use of more wear resistant bearing surfaces.

Adult↗
PubMed2000

Universal amplitude ratios of the renormalization group: two-dimensional tricritical Ising model.

The scaling form of the free energy near a critical point allows for the definition of various thermodynamical amplitudes and the determination of their dependence on the microscopic nonuniversal scales. Universal quantities can be obtained by considering special combinations of the amplitudes. Together with the critical exponents they characterize the universality classes and may be useful quantities for their experimental identification. We compute the universal amplitude ratios for the tricritical Ising model in two dimensions by using several theoretical methods from perturbed conformal field theory and scattering integrable quantum field theory. The theoretical approaches are further supported and integrated by results coming from a numerical determination of the energy eigenvalues and eigenvectors of off-critical systems in an infinite cylinder.

Journal Article↗
PubMed2000

Trace determination of urinary 3-hydroxybenzo[a]pyrene by automated column-switching high-performance liquid chromatography.

3-Hydroxybenzo[a]pyrene (3-OHB[a]P), one of the metabolites of benzo[a]pyrene (B[a]P), has been determined in human urine using an automated column-switching procedure. The hydrolysed biological sample is centrifuged just prior to being injected into a reusable precolumn loop, which is packed with a preparative phase and coupled on-line to a liquid chromatographic (LC) system. A rapid pre-treatment of the hydrolysed sample, consisting of a concentration and a crude clean-up, is performed on the precolumn. The analytes are then non-selectively desorbed with the LC eluent and the sample is cleaned again in three successive purification columns using the direct transfer or "heart-cut" technique. The pre-treatment does not exceed 3 min. and the entire analytical purification and separation procedure takes less than 30 min. Average 3-OHB[a]P recovery reaches 95% in the 1-50 ng/l range of urine, and the detection limit is 0.1 ng/l urine for a 3 ml injection of hydrolysed urine. The developed method was compared with a more time-consuming off-line method to analyse urines of B[a]P gavaged rats; the statistical treatment indicates that both methods are in agreement. The method was applied to purify and concentrate the urine samples of workers exposed and apparently unexposed to polycyclic aromatic hydrocarbons (PAHs).

Animals↗