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Biomedical subjects

J Hermans

Publications and source records attributed to J Hermans.

At least 667 records · Page 37Linked to original sources
PubMedDate not supplied

Size and density of fibrin fibers from turbidity.

In agreement with earlier observations that the angular dependence of light scattering by fibrin gels obeys the theory for light scattering by very long and thin rigid rodlike particles (intensity proportional to the square of half the scattering angle), we find that the turbidity, tau, of the less opaque gels varies as the inverse third power of the wavelength, lambda. Mass-length ratios of the fibers calculated from these two measurements closely agree. For fibrin gels containing fibers with a very high mass-length ratio (of which we had not been able to obtain interpretable scattering data), the turbidity is found not quite to vary as 1/lambda3. For these opaque gels, the fiber diameter is no longer negligible with respect to the wavelength. It is shown how the radius of gyration of the fiber cross section (and therefore the radius of cylindrical fibers) can be obtained from the ratio of slope and intercept of a plot of 1/tau lambda3 vs. 1/lambra2. The square of the radius of the fibers is found to be proportional to the mass-length ratio. The density of the fibers is calculated to be 0.28. This corresponds to a ratio of fiber volume to volume of protein contained in the fiber of 5.0.

Fibrin↗
PubMedDate not supplied

Pneumococcal bacteremia in adults over a 10-year period at University Hospital, Leiden.

The medical records on all cases of pneumococcal bacteremia in adults at the University Hospital, Leiden, over a 10-year period (1976-1986) were retrospectively reviewed. In this series of 147 episodes (an annual incidence of 0.8 episodes/10,000 adults), overall mortality was 25.9%. Factors significantly related to a higher mortality rate were shock, respiratory insufficiency, preexisting renal failure, and rapidly fatal underlying disease. Several laboratory abnormalities-such as a low percentage of band forms, an elevated level of serum lactate dehydrogenase, and hyperbilirubinemia-were significantly related to a poor outcome. Multilobar pneumonia and meningitis were both associated with high mortality, although not to a statistically significant degree. Discriminant analysis showed the presence of shock as the most powerful predictive factor of death. Surprisingly, prior splenectomy did not correlate with higher mortality. Treatment with beta-lactam antibiotics favorably influenced the outcome of illness in patients with ultimately fatal and nonfatal underlying disease, while the use of these agents in patients with rapidly fatal underlying disease did not correlate significantly with a good prognosis.

Adolescent↗
PubMedDate not supplied

Systolically gated 3D phase contrast MRA of mesenteric arteries in suspected mesenteric ischemia.

OBJECTIVE: Our goal was to assess the value of MRA for detecting stenoses in the celiac (CA) and superior mesenteric (SMA) arteries in patients suspected of having chronic mesenteric ischemia, using an optimized systolically gated 3D phase contrast technique. MATERIALS AND METHODS: In an initial study in 24 patients who underwent conventional angiography of the abdominal vessels for different clinical indications, a 3D phase contrast MRA technique (3D-PCA) was evaluated and optimized to image the CAs and SMAs. Subsequently, a prospective study was performed to assess the value of systolically gated 3D-PCA in evaluation of the mesenteric arteries in 10 patients with signs and symptoms of chronic mesenteric ischemia. Intraarterial digital subtraction angiography and surgical findings were used as the reference standard. RESULTS: In the initial study, systolic gating appeared to be essential in imaging the SMA on 3D-PCA. In 10 patients suspected of mesenteric ischemia, systolically gated 3D-PCA identified significant proximal disease in the two mesenteric vessels in 4 patients. These patients underwent sucessful reconstruction of their stenotic vessels. CONCLUSION: Cardiac-gated MRA may become a useful tool in selection of patients suspected of having mesenteric ischemia who may benefit from surgery.

Adult↗
PubMedDate not supplied

Cervical carcinoma: do fast SE and fat suppression techniques improve MR tumor staging at 0.5 T?

PURPOSE: Our goal was to compare fast SE (FSE) with T2-weighted conventional SE (CSE) MRI of cervical carcinoma and to evaluate the potential advantage of fat suppression technique. METHODS: We compared the tissue contrasts between cervical carcinoma and the surrounding tissues in 24 patients. The following MR sequences were obtained at 0.5 T: T1-weighted CSE (450/20 ms), T2-weighted CSE (2,500/45, 90), and T2-weighted FSE (4,800/120), the latter with and without fat suppression using fat-selective prepulses. RESULTS: T2-weighted FSE MRI provided significantly better contrasts between tumor and normal cervical stroma (p < 0.001) and between tumor and rectum wall (p < 0.05) than T2-weighted CSE MRI. T1-weighted SE MRI gave the highest tissue contrast between tumor and parametrial tissue (p < 0.001). Fat suppression did not further improve tissue contrasts. CONCLUSION: MR staging of cervical carcinoma is best done with the combination of T1-weighted SE and T2-weighted FSE images, without additional fat suppression.

Cervix Uteri↗
PubMedDate not supplied

Blood gas and pH in the human fetus with severe anemia.

Leiden University Hospital is the national referral center for the management of fetal isoimmunization in The Netherlands. In this observational study, blood gas and acid-base measurements from 286 pretransfusion samples and 214 paired posttransfusion samples of 113 fetuses were analyzed. In umbilical arterial blood, we found a significant positive correlation between the degree of anemia and pH, as well as a significant negative correlation between degree of anemia and pO2. However, umbilical venous blood gas and pH remained virtually unchanged even in severe anemia. During intrauterine transfusion with unbuffered adult red cells, there was a small but statistically significant decrease of pH and pO2 in fetal blood. We conclude that severe fetal anemia is associated with decreased umbilical arterial pH, but that umbilical venous pH remains normal until shortly before death.

Adult↗
PubMedDate not supplied

Internal biliary drainage, parenteral nutrition, and variation in the total parenteral nutrition feeding solutions: influence on the healing of colon anastomosis in jaundiced rats.

The influence of preoperative internal biliary drainage and various types of total parenteral nutrition (TPN) on the healing of a colon anastomosis in 50 jaundiced rats was investigated. Jaundice was induced by division and ligation of the common bile duct. After 5 days a colon anastomosis was made. Ten days thereafter the bursting pressure of the anastomosis was measured as an assessment of wound healing. Bursting pressures were significantly lower in jaundiced rats compared with a sham-operated nonjaundiced group. Preoperative internal biliary drainage significantly improved bursting pressure (p less than 0.001) as did preoperative TPN (p less than 0.001). In the second part of the study the influence of four different feeding solutions on the healing of a colon anastomosis was tested. Solutions with and without 20% fat emulsion and a solution with branched-chain amino acids were tested as well as glucose only. No significant differences were observed among these four groups on the parameters tested.

Alanine Transaminase↗
PubMedDate not supplied

The sub-acute center: a proposal for relocating elderly mental patients.

Both researchers and practitioners have become increasingly concerned with the plight of elderly mental hospital patients who are often inappropriately confined in state hospitals and then discharged from these facilities with little preparation for survival or attention given to the quality of community resources. This paper proposes the establishment of a new community care setting, a sub-acute center (SAC), which is designed to meet present inadequacies in the mental care system for the aged and combines elements of a foster home and a protective setting with a mental health aftercare component for more effectively preparing the elderly for independent community living. The SAC combines at least three concepts which are discussed: (a) the receiving station; (b) continuity of care; and (c) advocacy. The professional SAC staff and aides have many potential roles to play as practitioners, spokesmen, educators, consultants, and researchers.

Aged↗
PubMedDate not supplied

Reovirus serology in broiler parents and their progeny and its correlation with performance.

An intensive vertically integrated monitoring program for broiler breeders and their offspring was set up in a Belgian poultry integration between 1993 and 1997. Serology for anti-reovirus antibodies was performed by enzyme-linked immunosorbent assay on blood samples taken from the broiler parents throughout rearing and production and also on blood samples taken at day-old and at slaughter from the broilers. Furthermore, production parameters of the birds were registered. All data were used two by two in a simple correlation study to calculate the degree to which these variables were linearly correlated. The reovirus antibody pattern indicated frequent field infections breaking through vaccinal immunity in the broiler parents. Under the epidemiologic conditions of this study, high antibody titers in the parents or in the broilers at day-old were significantly correlated with poor feed conversion, increased mortality, increased slaughterhouse condemnation, and low production score in the broilers. These correlations strongly support the view that reovirus infections can be economically important under European conditions of broiler production. Improvement of reovirus vaccines or the vaccination scheme in broiler parents or both may lead to better production results in the broiler offspring.

Animal Husbandry↗
PubMedDate not supplied

Tumor load and surgical palliation in gastric cancer.

BACKGROUND/AIMS: Most patients with gastric cancer will have resection, even if their disease stage is beyond curability. Proper criteria to assess tumor load in patients deemed noncurative are lacking, and therefore, it is not clear which of these patients will benefit from resection. METHODOLOGY: Of 996 gastric cancer patients who had laparotomy in a national randomized trial of lymphadenectomy for gastric cancer, 285 (29%) were found to be noncurable because of remnant tumor, peritoneal metastases, distant lymph node metastases or liver metastases. They underwent a palliative procedure considered appropriate by the surgeon. Tumor load in this group was analyzed retrospectively by calculating the number of noncurability signs. RESULTS: The number of signs of noncurability was related to the type of surgical palliation chosen by the surgeon: of those patients with only one sign of noncurability, 68% had a palliative stomach resection but, of patients with two or more positive signs of noncurability only 36% had a stomach resection. Median survival after palliative resection was 253 days compared to 169 days after a nonresective procedure (P = 0.002). This survival advantage for resected patients disappeared when two or more signs of noncurability were found. CONCLUSIONS: For patients deemed noncurative, survival depends on tumor load. Accurate preoperative assessment of tumor spread may prevent unnecessary high-risk surgical interventions for patients with noncurative gastric cancer.

Adenocarcinoma↗
PubMedDate not supplied

Prospective comparative study of ultrasound, CT-scan, scintigraphy and laboratory tests to detect hepatic metastases.

The conventional methods of CT scan (CT), ultrasound (US), scintigraphy (SC), and laboratory tests (LDH, AP, 5-Nt) were prospectively compared in 135 patients with gastrointestinal carcinoma to define the most useful test to detect hepatic metastases. Thirty-six patients (26.7%) had hepatic metastases at laparotomy. Sensitivities were low: 46% for SC, 58% for US, 68% for CT and 63% for LDH. Accuracies ranged from 62% (LDH) to 78% (SC). No significant differences were found. Accurate and efficient detection of hepatic metastases is hampered by the relatively low sensitivity, specificity and accuracy of conventional imaging and laboratory tests.

Gastrointestinal Neoplasms↗
PubMedDate not supplied

Pharmacokinetics of the cytostatic drugs used in the CMF-regimen.

Forty-one clinical patients were studied on the first day of the first course of the CMF-regimen; administered by a fixed dosage scheme depending solely on body surface area of the patient in question. Parmacokinetic parameters were calculated for each drug: the data were analysed in conformity with the usual pharmacokinetic models. The results indicate a large pharmacokinetic variability, especially for cyclophosphamide (C). The large variability in plasma concentrations of C is presumed to be substantially attributable to the drug formula used.

Adult↗
PubMedDate not supplied

Analysis of post-operative hypalbuminaemia: a clinical study.

OBJECTIVE: Analysis of severity, causes and relevance of hypalbuminaemia developing after surgery. SUBJECTS: Patients undergoing elective aortic surgery (n = 11) or minor extra-abdominal surgery (n = 6). METHODS: Serum albumin concentration, blood loss, nitrogen balance and complications were determined until the fifth post-operative day. The contributions of haemodilution, albumin loss, albumin catabolism and redistribution were calculated using existing formula. The relation of hypalbuminaemia to the endocrine-metabolic response was determined. RESULTS: Significant hypalbuminaemia occurred after aortic surgery, in the absence of significant complications. No haemodilution occurred. Analysis indicated that 18% of hypalbuminaemia was caused by blood loss. Only 6% could be attributed to albumin catabolism, despite a significant correlation with the endocrine-metabolic response. Seventy-seven percent of hypalbuminaemia was attributed to albumin redistribution. No hypalbuminaemia occurred after minor surgery. CONCLUSION: Post-operative hypalbuminaemia is a normal finding early after aortic surgery. It is mainly caused by albumin redistribution, not by metabolic changes.

Abdomen↗
PubMedDate not supplied

Fine needle aspiration cytology of the breast with immediate reporting of the results.

The value of fine needle aspiration cytology (FNAC) of the breast with immediate reporting was determined in 503 consecutive aspirates. When the results of immediate and routine cytologic examination were compared, there was perfect agreement in 95.8% of the cases, with a kappa score of .92. In only 21 cases did discrepancies occur (4.2%), and when the results of FNAC were divided into normal and abnormal cytology, only four discrepancies were apparent. Provided that the results of immediately reported FNAC are interpreted in the context of clinical and mammographic findings, this approach provides a reliable diagnosis within a quarter of an hour and is therefore highly recommended.

Adolescent↗
PubMedDate not supplied

Differential effects of counterregulatory stress hormones on serum albumin concentrations and protein catabolism in healthy volunteers.

Postoperative hypoalbuminemia occurs frequently; however, the cause of this disorder is not clear. In a double-blind, placebo-controlled study we investigated to what extent hypoalbuminemia and protein catabolism are caused by counterregulatory stress hormones, which play an important role in the metabolic changes that follow surgery. We simulated the postoperative endocrine response in healthy volunteers with a cocktail of the counterregulatory hormones epinephrine, glucagon, and hydrocortisone. Saline was infused as a control in a second experiment. Serum albumin and stress hormone concentrations and nitrogen balance were measured for 34 h and were compared with published values for patients after abdominal surgery. Triple-hormone infusion mimicked the endocrine response after abdominal surgery adequately. It caused a negative nitrogen balance comparable with that after moderately severe surgery but no hypoalbuminemia (serum albumin < 35 g/L), although serum albumin was slightly reduced relative to the control group. No net nitrogen loss or hypoalbuminemia occurred after saline infusion. In conclusion, counterregulatory stress hormones do not cause hypoalbuminemia in healthy volunteers, but do produce protein catabolism.

Diuresis↗