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Biomedical subjects

J Hermans

Publications and source records attributed to J Hermans.

At least 415 records · Page 23Linked to original sources
PubMed1990

Effect of cloxacillin prophylaxis on the bacterial flora of craniotomy wounds.

During a double-blind placebo-controlled study, the effect of cloxacillin prophylaxis in craniotomies on samples taken for culture from 334 operation wounds in 279 patients was assessed. Patients and operations were equally divided over the cloxacillin and placebo groups. In the cloxacillin group significantly fewer samples contained microorganisms than was the case in the placebo group both just after the incision was made (p less than 0.05) and just before closure of the wound (p less than 0.001). The contaminating bacteria found most frequently were Propionibacterium acnes and Staphylococcus epidermidis. For material collected immediately after the incision, the percentage of cultures positive for S. epidermidis was significantly (p = 0.001) lower in the cloxacillin group than in the placebo group; the percentage of cultures with P. acnes did not differ between the two groups. For samples taken just before the wound was closed, the percentage of cultures with P. acnes or S. epidermidis was significantly (p = 0.008 and 0.003, respectively) lower in the cloxacillin than in the placebo group. In the placebo group neurosurgical infections occurred with P. acnes and/or S. epidermidis as causative microorganisms; in almost all cases those bacteria could be cultured from the edge of the wound. In none of the patients with an infection caused by S. aureus was the bacteria found in the operation area. In 2/6 infections in the cloxacillin group the infecting microorganisms could be cultured from the operation area. These findings support a significant reduction in the infection rate after craniotomy under cloxacillin prophylaxis compared with placebo.

Cloxacillin↗
PubMed1990

Value of anti-neutrophil cytoplasmic autoantibodies and other laboratory parameters in follow-up of vasculitis.

The presence of anti-neutrophil cytoplasmic autoantibodies (ANCA), detected by indirect immunofluorescence, is of high sensitivity and specificity in the diagnosis of Wegener's granulomatosis and related diseases, associated with vasculitis. Titres of immunofluorescence are thought to closely reflect disease activity. In a retrospective series of 266 sera of 23 patients with at least one positive test for ANCA, disease activity was correlated with ANCA, assayed by immunofluorescence and by enzyme-linked immunosorbent assay; with rheumatoid factor and with erythrocyte sedimentation rate. All tests were of limited value in predicting disease activity or relapse. A normal sedimentation rate and, to a lesser extent, a negative result of ANCA-immunofluorescence, were useful in excluding active disease.

Autoantibodies↗
PubMed1990

Abdominal ultrasonography: improved image quality with the combined use of a diet and laxatives.

Intestinal contents (gas and food particles) are well known to cause problems in abdominal ultrasonography by inducing confusing and inconclusive images. We prospectively studied the effect on the combination of a 2-day low-calorie, low gas-forming diet with laxatives on abdominal sonographic image quality. For a total group of 100 consecutive outpatients, 50 patients (diet-laxative or DL group) were randomly assigned to follow the preparation of a diet and laxatives, and 50 patients (control or C group) served as a control group without any special preparation. The sonographic imaging quality of abdominal organs and retroperitoneal structures was assessed without knowledge of which group the patients were assigned to. The DL group patients showed a significant improvement in visibility of the extra-hepatic common bile duct (p = 0.009), head and body of the pancreas (p = 0.015 and 0.004, respectively), para-aortic region (p = 0.001), and the iliac vessels (p = 0.0005). The combined use of a low-calorie, low gas-forming diet and laxatives improves the abdominal sonographic image quality of the above-mentioned structures to such an extent that the sonographer will be able to make more pertinent statements about the presence or absence of pathology.

Abdomen↗
PubMed1990

Assessment of resectability of carcinoma of the pancreatic head by ultrasonography and computed tomography. A retrospective analysis.

In order to establish the reliability of the assessment of tumour stage and hence of resectability of carcinoma of the pancreatic head by ultrasonography (US) and computed tomography (CT) a retrospective analysis was performed on 41 patients. Both direct imaging techniques were very accurate in detecting non-resectable disease, 100 and 85% respectively, but were much less accurate in predicting resectable cancer, 18 and 15% respectively. False-resectable results were established in 58% of US examinations and 42% of CT examinations. As demonstrated in this study, predicting resectability of carcinoma of the pancreatic head with US and CT is an inadequate method of assessing tumour stage and should be complemented by other techniques to ensure a reliable result.

Aged↗
PubMed1990

Sensitivity and specificity of acid phosphatase to detect prostate cancer using data from a hospital information system.

Indices of diagnostic tests, such as sensitivity and specificity, should be determined using diagnostic test results of patients tested in clinical practice. Hospital information systems that store data on diagnostic tests and diagnoses might be used for sampling the desired study population and in the actual process of collecting the data. This paper presents, as an example, a study calculating the sensitivity and specificity of the prostate-specific acid phosphatase test. All data needed in the study were obtained from the hospital information system of Leiden University Hospital. The final health status of each patient was assessed by the cancer registry of the system. The reason for ordering the test was deduced from data on histopathological examinations of prostatic tissue. The actual selections made from the central database are described in dataflow diagrams. The sensitivity of the test was found to be 0.34 and the specificity 0.88, using a discrimination value of 1.00 U/l. The impact of the reason for ordering the test on the specificity is illustrated. Possible biases of these measured values are discussed.

Acid Phosphatase↗
PubMed1990

The value of fine-needle aspiration biopsy in patients with nodular thyroid disease divided into groups of suspicion of malignant neoplasms on clinical grounds.

The accuracy of clinical diagnosis and fine-needle aspiration biopsy (FNAB) was evaluated in 169 patients surgically treated for nodular thyroid disease. Patients were divided into three groups with high, moderate, or low suspicion of malignant neoplasms on clinical grounds without previous knowledge of cytologic or histologic results. Histologic examination revealed an overall malignant neoplasm rate of 23%; the rate was 71%, 14%, and 11% for the groups with high, moderate, and low suspicion, respectively. The FNAB diagnostic interpretations of malignant and uncertain were considered positive. Overall sensitivity, specificity, and accuracy for FNAB were 92%, 71%, and 75%, respectively. Sensitivity in the high-, moderate-, and low-suspicion groups was 95%, 89%, and 88%, respectively; specificity was 88%, 72%, and 67%, respectively; and accuracy was 93%, 75%, and 69%, respectively. In our opinion, all patients in the group with high clinical suspicion need surgical treatment whatever the FNAB result; those with lower degrees of clinical suspicion and malignant or uncertain FNAB result [corrected] should also undergo surgery.

Biopsy, Needle↗
PubMed1990

Conservative versus operative treatment of displaced noncomminuted tibial shaft fractures. A retrospective comparative study.

The results of conservative (mainly, functional bracing) and operative treatment (mainly, plate fixation) have been compared in a retrospective study of 170 displaced noncomminutive tibial shaft fractures. The characteristics of the fractures in both treatment groups showed no significant differences. The follow-up analysis revealed no statistical differences in outcome between the two methods. However, because of the many factors analyzed and the restricted number of patients studied, it is impossible to compare all factors independently. Surgical treatment resulted in a higher rate of complications (such as implant failure, osteitis, and refracture) and a longer total hospitalization time. Conservative treatment showed a longer duration of fracture healing and a higher rate of malalignment. Malalignments of up to 10 degrees with no adverse effects have been seen so far. In conservative treatment, two fracture types were identified with a higher rate of malalignment: short oblique isolated tibial fractures and fully dislocated transverse crural fractures. Conservative therapy is favored, because there is less discomfort for the patient and the treatment is cost contained.

Adolescent↗
PubMed1990

Allogeneic bone marrow transplantation for leukemia in Europe: regional differences. Report from the Leukemia Working party of the European Group for Bone Marrow Transplantation.

The results of 1904 allogeneic HLA identical sibling donor bone marrow transplants performed in 52 European centers between 1979 and 1986 and reported to the EBMT leukemia registry were analysed by geographical location of the transplant. Patients were grouped into six regions: United Kingdom, Nordic Group, Benelux, France, Central Europe and Southern Europe. There were significant differences between these regions with respect to patient population and outcome. The relative proportion of the three major disease categories, stage and subtype of the diseases, graft-versus-host disease prevention methods, donor recipient sex combinations, age of the patient, year of the transplant and the time intervals from diagnosis to transplant, from diagnosis to first complete remission for acute leukemia and the time from first complete remission to the transplant varied from region to region. The analysis of outcome parameters showed a significant difference in relapse incidence from region to region. This influence of region was confirmed in a multivariate analysis and was independent of the other factors known to affect outcome. Leukemia-free survival and transplant-related mortality were not different. The reasons for these differences could not be explained by the data in the registry. We conclude that regional factors must be considered when bone marrow transplant data are compared and we postulate that pretransplant factors probably affect outcome more than was previously realized.

Adolescent↗
PubMed1990

The effects of negative regional lymph-node dissection on survival and disease-free interval of patients with stage-I malignant melanoma.

A group of 46 patients, with stage-1 malignant melanoma of intermediate thickness and histologically proven negative regional lymph nodes, was retrospectively reviewed. The aim of our study was to determine whether the prognosis of these patients had been worsened by the regional lymph-node dissections. There was no influence on the survival or disease-free interval.

Adolescent↗
PubMed1990

Interpretation of diagnostic cytology with likelihood ratios.

Sensitivity, specificity, and predictive values are commonly used to report the performance characteristics of a diagnostic test. With tests that by their nature have more than two classes of results, calculation of sensitivity and specificity demands the combination of categories into two classes, leading to a loss of diagnostic information. Fine-needle aspiration cytology of the breast is usually reported using four categories: definitely malignant, suspicious, benign, and unsatisfactory. We used likelihood ratios to show that fine-needle aspiration cytology of the breast appreciates each of these four categories fully. This approach is preferred above the usual one, which combines "definitely malignant" and "suspicious" categories as abnormal and often discards unsatisfactory aspirations from calculation. Knowledge of the prior probability of breast cancer and the likelihood ratio for a particular class of results of fine-needle aspiration cytology of the breast allows for easy calculation of the posttest probability of the disease. Application of this method should lead to more rational support from fine-needle aspiration cytology for clinical decision making.

Adolescent↗
PubMed1989

A new model to describe extrinsic protein binding to phospholipid membranes of varying composition: application to human coagulation proteins.

We introduce here a new model to describe the binding of extrinsic membrane proteins to acidic lipid membranes. In this view, macroscopic binding affinity is determined by two processes: nonspecific adsorption of protein to the membrane surface and association of acidic lipids with specific sites on the bound protein. We apply this model here to compare the binding of human prothrombin and factor X/Xa to phosphatidylglycerol (PG)- and phosphatidylserine (PS)-containing small unilamellar vesicles measured via relative light scattering. This comparison was undertaken because model membranes containing PS are much more effective in supporting thrombin formation than are membranes containing PG. Analysis of binding isotherms in terms of a traditional membrane binding model gave apparent dissociation constants systematically varying from 0.1 to 10 microM over a range of 8-65 mol% negatively charged phospholipid. With our new description of membrane binding, the dependence of binding data on the acidic lipid surface concentration revealed that only two or three acidic lipid molecules were associated with each surface-bound factor X/Xa or prothrombin molecule. Assuming four independent and equivalent acidic lipid binding sites per protein, it was possible to adjust the values of only the nonspecific adsorption equilibrium constant and the equilibrium constant describing binding of each species of acidic lipid to individual sites on the protein and thereby obtain a good simulation of log-linear binding isotherms for the full range of acidic lipid surface concentrations. The protein-associated binding sites had a greater affinity for PS than for PG; i.e., a lower surface concentration of PS was required to fill the binding sites.(ABSTRACT TRUNCATED AT 250 WORDS)

Factor X↗
PubMed1989

The significance of an isolated central nervous system relapse, occurring as first relapse in children with acute lymphoblastic leukemia.

In a retrospective study, which comprised the whole Dutch childhood population of approximately 3 million children, the authors assessed the influence of an isolated meningeal relapse, occurring as first relapse, together with some patient and treatment characteristics on prognosis in 142 children with acute lymphoblastic leukemia (ALL). Until their first relapse, patients were initially treated according to standard protocols, whereas the treatment for relapse was heterogeneous. Concerning the probability of achieving a second complete remission (CR) it appears that the duration of the first CR is the single most important prognostic factor. The duration of the first CR is also the most important factor with regard to the duration of the second CR, upon which also age and sex have a significant influence. Concerning the survival from the time of central nervous system (CNS) relapse, again the duration of the first CR appears to be the most important prognostic factor, followed by age and the institution of systemic reinduction treatment. Other factors, such as initial leukocyte count, attainment of first CR within 48 days, type of reinduction treatment, and the cerebral spinal fluid (CSF) blast count at the time of relapse, have a less important, but nevertheless significant influence on survival. The median survival from the time of CNS relapse is 25 months, the 5-year survival is 25%, whereas the ultimate survival will be less than 20%. From 90 patients who developed second or subsequent relapses, 75% experienced a bone marrow relapse during the follow-up period. From this study the authors conclude that CNS relapse in children with ALL carries a grave prognosis, which requires the institution of intensive retreatment programs.

Adolescent↗
PubMed1989

[Are hematologic reference values applicable to the healthy elderly?].

In the healthy elderly (65-90 years; 80 men, 75 women) the variability of haematological findings was examined and compared with the reference range. In the men, the ranges for haemoglobin valves (7.4-10.5 mmol/l) and erythrocyte counts (3.8-5.5 x 10(12)/l) proved to be lower than the reference intervals (8.5-10.9 mmol/l and 4.4-6.0 x 10(12)/l respectively). For the women no discrepancies were found. The question arises whether the reference limits for haemoglobin and erythrocytes should be lowered for elderly men.

Aged↗
PubMed1989

Nucleotide sequences of cDNA clones encoding the entire precursor polypeptide for subunit VI and of the plastome-encoded gene for subunit VII of the photosystem I reaction center from spinach.

Recombinant phage which encode the entire precursor polypeptide for subunit VI of the photosystem I reaction center have been selected from a lambda gt11 cDNA expression library made from polyadenylated RNA of spinach seedlings. The sequence predicts a precursor polypeptide of 144 amino acids (Mr = 15.3 kDa), a mature protein of 95 residues (Mr = 10.4 kDa) that lacks methionine, histidine and cysteine, and a transit peptide of 49 residues (Mr = 4.9 kDa). The corresponding gene(s) is (are) designated psaH. The gene for subunit VII, psaC, has been located in the small single-copy region of the spinach plastid chromosome using a synthetic oligonucleotide and a heterologous hybridization probe. It is part of a polycistronic transcription unit that is constitutively expressed and processed. Putative processing products include a monocistronic RNA for psaC. The polypeptide chain of 18 (deduced) amino acids is highly conserved and strikingly resembles bacterial-type ferredoxins. It harbours cysteine residues that appear to be involved in the ligation of the two 4Fe4S centres A and B in photosystem I. None of the two subunits appears to be membrane-spanning, and subunit VI, as subunit VII, is located at the reducing (stromal) side of the reaction center. All available information on the major subunits of photosystem I from spinach has been combined into a (revised) topographic model. Evidence that the innermost - plastome-encoded - core of photosystem I represents an old bacterial heritage in present day chloroplasts is discussed.

Amino Acid Sequence↗
PubMed1989

Clinical evaluation of pneumococcal meningitis in adults over a twelve-year period.

A retrospective study was performed to review the clinical features and outcome of 39 episodes of pneumococcal meningitis in 36 adult patients over a 12-year period. Overall mortality was 33.3%. Only a few of the deaths were directly related to the central nervous system disease and most of them were due to cardiorespiratory failure. Univariate analysis showed that death was more likely to occur in patients with advanced age, an absence of neck stiffness, a high pulse rate, an associated pneumonia, internal complications, or a long duration of the disease (greater than 7 days) before treatment was started. Patients who died had a higher erythrocyte sedimentation rate and serum bilirubin level and a lower serum sodium level than those who survived. Discriminant analysis showed the development of internal complications to be the strongest predictive factor of a poor outcome of illness. Two other important predictors of a poor outcome were the absence of neck stiffness and associated pneumonia. The history of a skull fracture or head surgery was significantly correlated with a better than average prognosis. The incidence of sequelae in survivors at the time of discharge amounted to 72%. None of the clinical features were significantly correlated with the development of sequelae, except a higher cerebrospinal fluid protein content.

Adolescent↗
PubMed1989

Comparison of the automated Bactec NR-660 with a conventional blood culture system.

The Bactec NR-660 blood culturing system was compared with a conventional system using 347 consecutively obtained clinical blood samples tested simultaneously. Of 46 clinically relevant isolates, 12 were detected by the conventional system only, 5 by Bactec only and 29 by both methods (0.05 less than p less than 0.10). The difference could not be explained by the results of additional in vitro tests. Of 12 isolates considered contaminants, 7 were isolated in the conventional system only, 2 in the Bactec system only and 3 in both systems (0.05 less than p less than 0.10). The two systems were approximately equal in speed of detection. A high rate of false indications of growth in the Bactec system could be reduced by applying different CO2 cut-off values.

Autoanalysis↗
PubMed1989

Comparison of test systems for recognition of methicillin resistance in Staphylococcus aureus.

Methicillin resistance in Staphylococcus aureus can be difficult to recognize because it may be expressed in only a small portion of the population. The optimal reference to use in comparing different test systems is controversial. In this study MIC values of less than or equal to 4 mg/l as observed in two experiments, each including 12 test systems (24 h incubation), were used to define strains as methicillin-susceptible. This strict standard was used to compare 24 quantitative and 36 agar diffusion test systems applied to 61 strains. These test systems included six agar media (Mueller Hinton, Oxoid and BBL; and Iso-Sensitest, Oxoid; all with and without 5% NaCl), three broth media of the same type, two incubation temperatures (30 degrees C and 37 degrees C), two incubation times (24 h and 48 h) and five disc types [methicillin 10 micrograms (M 10), three types of methicillin 5 micrograms (M 5) and oxacillin 1 microgram (O 1)]. Standardized high inocula were used. It was concluded that 24 h incubation is preferable to 48 h; at 24 h, differences in recognition of methicillin-resistant Staphylococcus aureus (MRSA) among 12 quantitative test systems were not statistically significant; incubation at 30 degrees C gave slightly better results in diffusion tests. Reproducibility of quantitative data (Friedman test) was better on Mueller Hinton media (p less than 0.001) than on Iso-Sensitest medium in both dilution and agar diffusion test systems. The rank order of discs was M 5 greater than M 10 greater than O 1 (p less than 0.001). An inhibition zone of less than 13 mm with a M 5 micrograms (BBL) disc should be interpreted as MRSA.

Culture Media↗