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Biomedical subjects

C van der Meer

Publications and source records attributed to C van der Meer.

At least 19 recordsLinked to original sources
PubMed1999

Comparison of four HTLV-I and HTLV-I + II ELISAs.

BACKGROUND: Various countries require blood donor screening using assays applying specific HTLV-I and HTLV-II antigens. We evaluated the sensitivity and specificity of 4 anti-HTLV-I + II ELISAs (Abbott, Murex, Organon Teknika and Ortho). METHODS: Panel A consisted of HTLV-I-positive individuals (n = 41), panel B of Mixed Titer Performance Panel 204 (Boston Biomedica Inc. panels C and D of dilution series from HTLV-I-positive (n= 30) and HTLV-II-positive (n =20) individuals and panel E of sera from first-time blood donors (n = 1,055). RESULTS: In HTLV-I- and -II-positive samples, a sensitivity of 100% could be observed in all 4 ELISAs. In diluted HTLV-I- and -II-positive samples, probit analysis revealed that the Murex assay had the highest analytical sensitivity, followed by the ELISAs from Ortho, Abbott and Organon Teknika. In specimens from first-time donors, a specificity of 100% was observed in ELISAs from Murex, Organon Teknika and Ortho, and of 99.7% in the assay from Abbott. CONCLUSION: The 4 anti-HTLV-I + II ELISAs studied were appropriate as screening tests.

Blood Donors↗
PubMed1994

Pharmacist-physician co-operation at a regional level.

In the Dutch region of "Betuwe" the hospital pharmacists and community pharmacists together provide short drug letters about new drugs, which are sent bimonthly to all the practising general practitioners (n = 83) and medical specialists (n = 50) in this region. A survey was conducted among these physicians in order to investigate their opinion about and reported use of the drug letters in comparison with other drug-information sources. The majority of the responding physicians (response rate 68%) was found to read the drug letter frequently and evaluated the drug letter as a useful source of information about drugs, especially its section about the advantages and disadvantages of the new drug compared to other drugs. With respect to the different stages of the drug-adoption process, the drug letter was found to be the most frequently used information source at the decision stage. At the introduction stage the pharmaceutical industry representative seems to be the most frequently used source of information, while at the information stage it is the "Geneesmiddelenbulletin" (Drug Bulletin). The majority of the responding general practitioners reported to participate in local group meetings with pharmacists. However, in only 20% of these group meetings attention is given to the drug letter. Since it is known that written information has only a limited influence on the physician's behaviour, the influence of the "Betuwe Circulaire" may increase when attention is paid to it in the local contacts between pharmacists and physicians.

Drug Information Services↗
PubMed1993

[Udder infections with coagulase-negative staphylococci in freshly calved heifers].

To determine the prevalence of udder infections in fresh calved heifers all quarters of 98 heifers on eleven commercial farms were sampled weekly during the first eight weeks of lactation. The samples during the first four weeks of this period were used for bacteriological examination and in all samples a somatic cell count was made. The prevalence of S. aureus after calving in these heifers was 12.5%. Coagulase-negative staphylococci (CNS) were isolated from half of the heifers. The predominant coagulase-negative staphylococcus species were S. xylosis and S. hyicus. The CNS, with exception of S. hyicus, had a very small effect on the cell count.

Animals↗
PubMed1987

A method for hemorrhagic shock in the rat.

Normovolemic hemorrhagic shock was induced in unanesthetized as well as anesthetized rats. The animals were bled according to predetermined schedules followed by reinfusion of all shed blood. In these models mortality during the hypovolemic phase was avoided, while practically 100% mortality ensued a number of hours after the reinfusion. To this end, a certain individualization of the bleeding procedure was necessary. The pathology induced was very similar in the two models. The survival time as well as the course of the plasma-glucose concentration (a tendency to a high degree of hypoglycemia) and the plasma-K+ concentration (extreme hyperkalemia) were also very similar. The causes of the hypoglycemia and hyperkalemia are not elucidated.

Anesthesia↗
PubMed1986

Trypanosoma brucei and T. vivax: salicylhydroxamic acid and glycerol treatment of acute and chronically infected rats.

In rats infected with monomorphic Trypanosoma brucei brucei, the efficacy of the therapy with salicylhydroxamic acid plus glycerol, i.e., combined therapy, decreased with increasing time after infection. It failed completely after the infection was made chronic by suboptimal treatment for 6 weeks. When this chronic infection had been established and "optimal" treatment was given, viable trypanosomes could still be detected 1 day later in brain and muscle but not in blood. In most organs, the concentrations of salicylhydroxamic acid and glycerol were lower than in the blood plasma; the maximum concentration of glycerol in the brain was only 20% of that in plasma. The most likely explanation for the failure of the combined therapy is that, in certain tissues, the concentration of the drugs remains too low to kill extravascular trypanosomes. Other explanations, such as the selection of a resistant strain or the survival of (extravascular) forms with a more active mitochondrion, could be excluded with a high degree of probability. Suramin was very effective, even after combined therapy had failed repeatedly, while melarsoprol was less effective. As in combined therapy, the dose of melarsoprol that could cure an acute infection was insufficient to cure a chronic infection. Combined therapy failed after a spontaneous chronic infection with T. b. rhodesiense had existed for 5-7 weeks, but it was effective in T. vivax infected rats even when parasitemia had been present for at least 4 days. Effective alternative schedules for combined therapy were not found.

Animals↗
PubMed1986

Studies on hyperkalemia as a cause of death in intestinal ischemia shock in rats.

Intestinal ischemia shock was induced either by temporary occlusion of the three splanchnic arteries for 40 min (SAO-shock) or by temporary occlusion of the portal vein for 35-40 min (PVO-shock). In both types of shock, life can be considerably prolonged (5-8-fold) by treatment with rat plasma plus glucose. Eventually, death is caused by heart failure due to hyperkalemia (plasma K+ concentration greater than 10 mmol/l). The amount of K+ causing this hyperkalemia is estimated at roughly 10% of the total body K+. Acidosis, low blood pressure, reduced kidney function, and disintegration of erythrocytes in the gastrointestinal (GI) tract probably are of no or minor importance in causing this extreme hyperkalemia. No indication was found that the liver, the skeletal muscles, or the erythrocytes release K+. Although the K+ concentration of the contents of the GI tract as well as the K+ transport by the portal vein were increased, the source of the excess K+ remains obscure. Removal of the contents of the stomach and small intestine, followed by flushing of the gastrointestinal tract, may have a favorable effect on the course of plasma K+ (and plasma glucose) concentration, indicating that toxic products from the damaged intestines may be important lethal factors.

Acidosis↗
PubMed1985

Studies on the site of the block in gluconeogenesis causing severe hypoglycemia in intestinal ischemia shock in rats.

Intestinal ischemia shock was induced by 35 to 40-min portal vein occlusion (PVO). After treatment with rat plasma a severe hypoglycemia ensues which is caused by a block in gluconeogenesis. This hypoglycemia is not affected by treatment with adrenaline, glucagon, nicotinadenine dinucleotide (NAD), adenosine triphosphate (ATP) alanine (A), or pyruvate (P), while fructose (F) and dihydroxyacetone (DHA) slightly increase the plasma glucose concentration. If F or DHA are combined with NAD a considerable hyperglycemic effect is observed, but NAD plus A or P is ineffective. A similar marked rise in plasma glucose is observed if F is combined with nicotinamide, adenylic acid, or histamine. NAD causes vasodilatation in the splanchnic area and an increased portal flow. It is concluded that the effect of NAD is the result of an increased uptake of suitable substrates of gluconeogenesis from the peritoneal cavity and/or an increased availability of these substrates to the liver. During the development of PVO shock, portal venous flow diminishes considerably. This reduced flow may be the result of vasoconstriction caused by the high level of plasma adrenaline.

Adenosine Triphosphate↗
PubMed1983

Hyperparathyroidism following irradiation of benign diseases of the head and neck.

In a series of 73 consecutive patients with hyperparathyroidism (HPT) eight patients gave a history of irradiation of head and neck because of benign diseases. The average interval between irradiation and definite diagnosis was 34 years. Intermittent hypercalcaemia was found in three patients. Microscopic examination of pathologic parathyroid glands of three patients showed a predominance of oxyphil cells. Thyroid abnormalities occurred more frequently in irradiated patients than in nonirradiated patients with HPT. Reviewing clinical and experimental data an etiologic role of irradiation in the pathogenesis of HPT appears present.

Adolescent↗
PubMed1982

Induction of acquired cellular resistance in mice with viable and macrophage-processed Listeria monocytogenes.

Intracutaneous immunization of mice with 10(5) or 10(6) viable listeria resulted in acquired cellular resistance (ACR) of short duration (7 days). The period during which viable Listeria monocytogenes had to be present in order to induce ACR was estimated by killing the listeria at different times after immunization by injecting the bactericidal antibiotic amoxycillin. The killing of listeria within 6 h after injection prevented the induction of A CR completely, between 6 and 12 h partially, while survival of listeria within animals for at least 18 h was required for the induction of complete protection. To determine whether multiplication of viable listeria was a prerequisite for the induction of ACR, the bacteriostatic antibiotic minocycline was injected for four days after immunization. Induction of ACR was only possible if the dose of viable listeria was large enough to permit a proportion of the listeria to escape bacteriostasis. Interaction of peritoneal macrophages of normal mice and viable listeria yielded a supernatant which induced specific ACR in normal recipient mice. No ACR could be induced with supernatant obtained from normal macrophages after digestion of killed listeria. A reduced level of ACR was obtained with supernatant collected after interaction of macrophages from immune mice and viable listeria. The immunogenic material present in the supernatant of normal macrophages after interaction with viable listeria is thermolabile, has a molecular weight of over 300,000, and is not affected by treatment with DNase, RNase, or trypsin.

Amoxicillin↗
PubMed1982

Different pig phenotypes affect adherence of Escherichia coli to jejunal brush borders by K88ab, K88ac, or K88ad antigen.

At least five different porcine phenotypes were distinguished with the three serological variants of the K88 antigen in the brush border adhesion test. Pigs of one phenotype (A) are susceptible to adherence of all three variants, pigs of three phenotypes are susceptible to only two (B and C) or one (D) of the K88 variants, and pigs of one phenotype (E) are entirely resistant to adhesion of K88 antigen did not interfere with the adhesion of K88ab- or K88ac-positive Escherichia coli, whereas in most cases K88ab and K88ac antigen completely blocked the adhesion of K88ad-positive E. coli. Likewise, K88ab antigen blocked the adhesion of K88ac-producing E. coli to both type A and type B brush borders, and vice versa.

Adhesiveness↗