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Biomedical subjects

H Putter

Publications and source records attributed to H Putter.

17 recordsLinked to original sources
PubMed2003

[Diagnostic surplus value of echography in children with acute abdominal pain].

OBJECTIVE: To assess the role of echography in the diagnosis of acute abdominal symptoms in children. DESIGN: Prospective, descriptive. METHOD: During one year (1 June 1999-31 May 2000), abdominal ultrasonography was performed in all children with abdominal pain less than 2 weeks, who were referred to the emergency department of the Red Cross Hospital in The Hague (the Netherlands). An initial clinical diagnosis was made on the basis of the medical history, a physical examination and the results of laboratory tests. Subsequently, ultrasonography was performed by a radiologist who was unaware of the clinical diagnosis. A working hypothesis was reached on the basis of the clinical findings and the results of echography. The final diagnosis was made on the basis of either a histologic investigation after surgery or the condition at discharge. RESULTS: The study included 112 patients. The mean age was 9 years and 54% were boys. Acute appendicitis was ascertained in 48 children. The sensitivity of the clinical findings was 88% and the specificity 70%. The sensitivity of the clinical findings together with ultrasonography was 88% and the specificity 91%. The positive predictive value of the clinical findings alone was 69% and of the clinical findings together with ultrasonography 88%. CONCLUSION: Echography has added value in the diagnosis of acute abdominal pain in children; it increases the specificity of the physical examination. The number of negative laparotomies was decreased by the use of ultrasonography.

Abdomen, Acute↗
PubMed2002

A Bayesian approach to parameter estimation in HIV dynamical models.

In the context of a mathematical model describing HIV infection, we discuss a Bayesian modelling approach to a non-linear random effects estimation problem. The model and the data exhibit a number of features that make the use of an ordinary non-linear mixed effects model intractable: (i) the data are from two compartments fitted simultaneously against the implicit numerical solution of a system of ordinary differential equations; (ii) data from one compartment are subject to censoring; (iii) random effects for one variable are assumed to be from a beta distribution. We show how the Bayesian framework can be exploited by incorporating prior knowledge on some of the parameters, and by combining the posterior distributions of the parameters to obtain estimates of quantities of interest that follow from the postulated model.

Bayes Theorem↗
PubMed2002

Score test for detecting linkage to quantitative traits.

The two most popular methods to detect linkage of a quantitative trait to a marker are the Haseman-Elston regression method and the variance components likelihood-ratio test. In the literature, these methods are frequently compared and the relative advantages and disadvantages of each method are well known. In this article, we derive a score test for the variance component attributable to a specific quantitative trait locus and show that for sib-pairs it is mathematically equivalent to a recently proposed version of the Haseman-Elston method that optimally combines the sum squared and the difference squared of the centered phenotype values of the sibs. Because score tests and likelihood-ratio tetsts are equivalent for large sample sizes, the variance components likelihood-ratio test is also asymptotically equivalent to this optimal Haseman-Elston test. This fact gives a theoretical explanation of the empirical observation from simulation studies reporting similar power of the variance components likelihood-ratio test and the optimal Haseman-Elston method. Perhaps more importantly for practical purposes, the score test can also be extended in a natural way to support the simultaneous analysis of more than two subjects and multivariate phenotypes.

Chromosome Mapping↗
PubMed2002

Impact of the introduction and training of total mesorectal excision on recurrence and survival in rectal cancer in The Netherlands.

BACKGROUND: Local control and survival following surgical treatment of rectal cancer have been improved by the introduction of total mesorectal excision (TME). The aim of this study was to determine the nationwide impact of the introduction and training of TME on recurrence and survival in rectal cancer. METHODS: Short- and long-term outcomes of a recently published trial of rectal cancer surgery (TME trial) were compared with results from an older trial (cancer recurrence and blood transfusion (CRAB) trial), in which conventional surgery was performed without quality control. Only patients who were operated on with curative intent and who did not receive neoadjuvant radiotherapy were studied. Differences in clinicopathological characteristics were corrected for by multivariate analysis. To ensure valid comparisons, only events that occurred within 2 years of operation were analysed with regard to long-term outcome. RESULTS: In the univariate analysis, a higher clinical anastomotic leak rate was found in patients following low anterior resection in the TME trial (P = 0.046), but this association was not significant in the multivariate analysis. The local recurrence rate decreased from 16 per cent in the CRAB trial to 9 per cent in the TME trial, and type of operation (conventional (CRAB trial) versus TME (TME trial)) was an independent predictor of local recurrence (P = 0.002). Type of operation was also an independent predictor of overall survival (P = 0.019); there was a higher survival rate in the TME trial. CONCLUSION: The introduction and training of TME has led to improved long-term outcome of patients with rectal cancer in the Netherlands.

Adult↗
PubMed2002

Value of palliative resection in gastric cancer.

BACKGROUND: Western patients with gastric cancer often present with incurable disease. The role of palliative surgical resection is still debatable. Non-curatively treated patients from the Dutch Gastric Cancer Trial were studied to define more accurately which patients might benefit from palliative resection. METHODS: In the Dutch Gastric Cancer Trial 285 (26 per cent) of the randomized patients were found to have incurable tumours at laparotomy. Four signs of incurability were noted: irresectable tumour (T+), hepatic metastasis (H+), peritoneal metastasis (P+) and distant lymph node metastasis (N4+). Patients had either an explorative laparotomy, a gastroenterostomy, or a resection (partial or total). In the analysis, particular attention was paid to the prognostic factors of age, number of metastatic features, and a combination of these. RESULTS: Overall survival time was greater if a resection was performed (8.1 versus 5.4 months; P < 0.001). For patients aged over 70 years there was still a survival advantage of about 3 months if resection was carried out. Morbidity and perioperative mortality rates in this older age group were, however, high (50 and 20 per cent respectively). For patients with one metastatic site a resection was of significant benefit (survival 10.5 versus 6.7 months; P = 0.034). For patients with two or more metastatic sites resection had no significant survival advantage (5.7 versus 4.6 months; P = 0.084). Combination of these factors indicates that patients aged less than 70 years with one metastatic site will benefit significantly from a palliative resection, in contrast to other combinations of factors. CONCLUSION: Age as well as the number of metastatic sites should be taken into account when a palliative resection is considered. Palliative resection may be beneficial for patients under 70 years of age if the tumour load is restricted to one metastatic site.

Adult↗
PubMed2001

Preoperative radiotherapy combined with total mesorectal excision for resectable rectal cancer.

BACKGROUND: Short-term preoperative radiotherapy and total mesorectal excision have each been shown to improve local control of disease in patients with resectable rectal cancer. We conducted a multicenter, randomized trial to determine whether the addition of preoperative radiotherapy increases the benefit of total mesorectal excision. METHODS: We randomly assigned 1861 patients with resectable rectal cancer either to preoperative radiotherapy (5 Gy on each of five days) followed by total mesorectal excision (924 patients) or to total mesorectal excision alone (937 patients). The trial was conducted with the use of standardization and quality-control measures to ensure the consistency of the radiotherapy, surgery, and pathological techniques. RESULTS: Of the 1861 patients randomly assigned to one of the two treatment groups, 1805 were eligible to participate. The overall rate of survival at two years among the eligible patients was 82.0 percent in the group assigned to both radiotherapy and surgery and 81.8 percent in the group assigned to surgery alone (P=0.84). Among the 1748 patients who underwent a macroscopically complete local resection, the rate of local recurrence at two years was 5.3 percent. The rate of local recurrence at two years was 2.4 percent in the radiotherapy-plus-surgery group and 8.2 percent in the surgery-only group (P<0.001). CONCLUSIONS: Short-term preoperative radiotherapy reduces the risk of local recurrence in patients with rectal cancer who undergo a standardized total mesorectal excision.

Adenocarcinoma↗
PubMed2001

Reduced need for vasopressors in patients receiving aprotinin during orthotopic liver transplantation.

BACKGROUND: Graft reperfusion in orthotopic liver transplantation is often associated with significant hemodynamic changes, including decreased systemic vascular resistance and arterial blood pressure. Vasopressive drugs are often required to maintain adequate perfusion pressure during the early postreperfusion period. The exact mechanism of this postreperfusion syndrome is unknown, but release of bradykinin, a potent vasodilatator, via the kallikrein system may play a role. Aprotinin is a broad-spectrum inhibitor of serine proteases such as kallikrein and therefore may ameliorate the postreperfusion syndrome and reduce the need for vasopressors. METHODS: In a randomized, double-blind study, the authors compared hemodynamic variables (systemic vascular resistance, cardiac index, arterial blood pressure, mean pulmonary artery pressure, central venous pressure) and the requirement of epinephrine during transplantation in 67 patients who received either high-dose aprotinin (2 x 10(6) kallikrein inhibitor units [KIU] at induction, continuous infusion of 1 x 10(6) KIU/h, 1 x 10(6) KIU before reperfusion; n = 24), regular-dose aprotinin (2 x 10(6) KIU at induction, continuous infusion of 0.5 x 10(6) KIU/h; n = 21), or placebo (n = 22). RESULTS: Baseline characteristics were similar for all three groups. Erythrocyte transfusion requirement was significantly higher in the placebo group compared with both aprotinin-treated groups. No major differences in hemodynamic variables were found between the three groups. The total amount of epinephrine (median, range) used during transplantation, however, was significantly lower in patients who received aprotinin (high dose, 20, 0-170 microg; regular dose, 30, 0-140 microg), compared with patients who received placebo (70, 0-2,970 microg; P = 0.0017). This difference was largely attributable to differences in the early postreperfusion period. CONCLUSIONS: Prophylactic use of aprotinin ameliorates the postreperfusion syndrome in orthotopic liver transplantation, as reflected by a significant reduction in vasopressor requirements.

Adult↗
PubMed2000

Slower decline of plasma HIV-1 RNA following highly suppressive antiretroviral therapy in primary compared with chronic infection.

OBJECTIVES: To study the effect of highly suppressive antiretroviral therapy on the slopes of HIV-1 RNA decline in primary compared with chronic HIV-1 infection. METHODS: Slopes of HIV-1 RNA decline in plasma were compared before and after the start of highly suppressive antiretroviral therapy from five acutely infected patients who started treatment 2 to 5 weeks following the onset of clinical symptoms. Slopes of decline after the initiation of therapy were also compared with those found in 12 chronically infected individuals on the same therapy. Numbers and percentages of activated CD4 and CD8 T cells at baseline were compared as well. RESULTS: The pre-treatment slopes of HIV-1 RNA decline in the acutely infected individuals increased significantly (P = 0.0001) after the start of anti-retroviral therapy. However, these post-treatment slopes were lower than those found in the chronically infected individuals (P= 0.012). Slopes were inversely correlated (P= 0.012) with baseline HIV-1 RNA. Although the number of CD38+HLA-DR+ CD4 cells was higher in primary infection (P= 0.02), the percentage did not differ between primary and chronic infection. CONCLUSIONS: These findings indicate that antiretroviral therapy contributes significantly to the clearance of HIV-1 during primary infection. Based on the mathematical model the less steep RNA slope following the start of treatment in primary infection can be predicted to be the result of lower clearance of productively infected cells and higher burst size per cell per unit time. This may indicate a growing immune response to HIV-1 in this very early stage of infection.

Acute Disease↗
PubMed2000

Value of different assays for detection of human cytomegalovirus (HCMV) in predicting the development of HCMV disease in human immunodeficiency virus-infected patients.

In the present prospective study, five blood tests for detection of human cytomegalovirus (HCMV), nucleic acid sequence-based amplification (NASBA) for detection of early (immediate-early antigen) and late (pp67) mRNA, PCR for detection of HCMV DNA (DNA PCR), culture, and pp65 antigenemia assay, and culture and DNA PCR of urine and throat swab specimens were compared for their abilities to predict the development of disease caused by HCMV (HCMV disease). Of 101 human immunodeficiency virus (HIV)-infected patients with </=100 CD4(+) lymphocytes per mm(3), 25 patients developed HCMV disease. The pp65 antigenemia assay (sensitivity, 50%; specificity, 89%) and DNA PCR of blood (sensitivity, 69%; specificity, 75%) were most accurate in predicting the development of HCMV disease within the next 12 months. Both blood culture and late pp67 mRNA NASBA had high specificities (91 and 90%, respectively) but low sensitivities (25 and 13%, respectively). The sensitivities of urine culture, DNA PCR, throat swab specimen culture, DNA PCR, and NASBA of blood for detection of the immediate-early antigen were 73, 87, 53, 67, and 63%, respectively, and the specificities were 58, 46, 76, 60, and 72%, respectively. The positive predictive values of all tests however, were low and did not exceed 50%. In conclusion, virological screening by these qualitative assays for detection of HCMV is of limited value for prediction of the development of HCMV disease in HIV-infected patients.

AIDS-Related Opportunistic Infections↗
PubMed1992

Diastema closure: a case report.

This clinical study describes two combined modalities of treatment, orthodontic and porcelain laminate placement, to facilitate diastema closure. Geristore, a dual-cure fluoride-releasing composite was mixed to bond orthodontic brackets in place. H6 elastic bands were used with the orthodontic brackets to close the diastemas sufficiently and to allow the placement of Cerinate porcelain laminates to produce a beneficial cosmetic effect.

Dental Veneers↗
PubMedDate not supplied

Innominate osteotomy in Perthes disease.

A retrospective study was performed in 27 patients who underwent innominate osteotomy for the treatment of severe Perthes disease. Time intervals between surgery and final follow-up ranged from 5 years to 16 years 4 months. Preoperative and postoperative periods of treatment were often more prolonged than those reported by Salter. One-half of the patients were less than 6 years of age at onset of the disease. A number of patients had significant deformity of the femoral head. Nevertheless, clinically good or fair results were obtained in 88% of the patients and poor results were found in 12%.

Age Factors↗
PubMedDate not supplied

Simultaneous placement of multiple porcelain veneers.

Although laminate veneers are usually placed individually in order to avoid bonding the anterior teeth together, an alternate technique is presented. The technique described is efficient and time-saving.

Dental Bonding↗
PubMedDate not supplied

Clinical technique for an in-office porcelain modification.

All porcelain restorations, especially intra- and extracoronal restorations, have become an accepted treatment modality for the esthetic restoration of posterior teeth. One problem with these restorations is the limited ability to modify the porcelain when a proximal contact is not present or there is an open margin. Using a low-fusing porcelain in a glazing oven, practitioners can easily accomplish such modifications during the try-in and cementation appointment for porcelain inlays. This technique eliminates the need for returning the porcelain inlay to the laboratory for modification and a second patient visit to complete the restoration. This paper describes an in-office procedure for modifying porcelain restorations and a scanning electron micrographic evaluation of the etched porcelain surface after using this modification technique.

Acid Etching, Dental↗
PubMedDate not supplied

Bleaching and/or porcelain veneers: case reports.

Four case studies are presented in which the concept that bleaching, porcelain veneer restorations, or a combination of both constitute a conservative treatment approach for discolored, malformed, malaligned, and worn dentition. These treatments can be used effectively not only for aging dentitions, but also for the very young, which makes them an attractive treatment modality.

Adult↗
PubMedDate not supplied

At-home bleaching system: effect on gingival tissue.

This study evaluated the effects of an at-home vital bleaching system on gingival responses over a 6-week period. Objective measures were utilized to measure and monitor gingival inflammation over this period of time. Vital bleaching was performed as follows: (1) bleaching gel in a prefabricated mouthguard and (2) an ad-mix technique--bleaching gel and toothpaste in a 1:1 ratio. In addition a control group used a placebo in a prefabricated mouthguard. The at-home vital bleaching system produced no adverse gingival tissue responses. Furthermore, the at-home vital bleaching system helped produce a therapeutic effect on inflamed gingival tissues over the course of the study.

Adult↗