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Biomedical subjects

K A Neftel

Publications and source records attributed to K A Neftel.

At least 37 records · Page 2Linked to original sources
PubMed1986

Toxicologic and pharmacologic considerations in the choice of empiric parenteral antibiotics.

The last five years have produced an explosive development of new beta-lactam compounds with extended bacterial spectra to include most of the gram-positive cocci as well as the gram-negative bacilli. With the exception of activity against enterococci, there are now third-generation cephalosporins with a spectrum of activity similar to that of the aminoglycosides. In addition, beta-lactams retain a high level of activity against anaerobes and against aerobes surviving in anaerobic conditions, a capacity that is lacking with the aminoglycoside group of antibiotics. The beta-lactams in general and some specific compounds in particular (moxalactam, ceftriazone) have a good penetration into the cerebrospinal fluid, a capacity that is also lacking with the aminoglycosides. Since there is a wide range of different spectra of activity among penicillins and cephalosporins, it is also possible to choose an antibiotic with a spectrum restricted to the offending microorganisms. Finally, because the potential toxicity of beta-lactams is less than that of the aminoglycosides (with the possible exception of myelotoxicity), the first choice of antibiotic in a patient with suspected severe infection should be a beta-lactam. The addition of an aminoglycoside should be reserved for those situations in which a synergistic action between the beta-lactam and the aminoglycoside antibiotics is expected to increase the efficacy of the beta-lactam alone, e.g., enterococcal infections, Pseudomonas aeruginosa infections, infections in severely neutropenic patients, or bacterial endocarditis.

Aminoglycosides↗
PubMed1986

Amodiaquine induced agranulocytosis and liver damage.

Seven cases of agranulocytosis and two of liver damage that were probably due to amodiaquine treatment were studied. In five cases agranulocytosis was combined with liver damage, and in one case of primary liver damage moderate neutropenia was present. Three patients died. High total doses or prolonged duration of treatment, or both, appear to favour the occurrence of these reactions. The clustering of five of the seven cases of agranulocytosis within six months in one medical centre indicates that the risk to benefit ratio of amodiaquine for malaria prophylaxis should be re-evaluated.

Adolescent↗
PubMed1986

[Radioimmunologic detection of IgE and IgG antibodies against drugs. Conclusions after experience with over 1200 patients].

Based on the radioallergosorbent test (RAST), the authors have developed a series of assays to detect IgE and IgG antibodies against a number of frequently used drugs. In this system drugs bound covalently to cellulose paper are incubated with serum and washed; the hapten-specific IgE and IgG antibodies are then qualified and quantified by means of 125I-labelled anti-human IgE and IgG respectively. Thus far the sera of 1,228 patients have been analyzed following therapy with betalactam antibiotics, co-trimoxazole, salicylates, pyrazolones, flavonoids and tetrahydroisoquinoline. The induction of IgG antibodies is a frequent occurrence and that of IgE rare. Isolated high titers of IgE are associated mainly with anaphylactic reactions; in the presence of simultaneously raised IgG titers such side reactions are often absent. Highest IgG titers were found in patients with immune hemolysis after betalactam antibiotics, flavonoids and tetrahydroisoquinoline. In the other types of side reaction specific IgG titers were not significantly higher than in patients without side reactions. The estimation of circulating antibodies against drugs cannot yet be utilized diagnostically except in the rare cases of anaphylactic side reactions. However, the method described permits specific and sensitive detection of sensitization and is suited for scientific purposes.

Clinical Trials as Topic↗
PubMed1986

[IE and IgG antibodies against flavonoids following therapy with flavonoid-containing drugs].

During treatment with flavonoid drugs a number of patients developed adverse reactions such as fever, various skin eruptions and intravascular hemolysis. The appearance of flavonoid-specific IgE and IgG antibodies and its possible relation to the observed side effects was studied on a total of 168 individuals treated with flavonoid drugs: 71 patients received troxerutin (Venoruton) parenterally to improve tolerance of radiation therapy, 12 patients were treated intravenously with silymarin (Legalon) for amanita intoxication and 77 patients received various flavonoid drugs for other indications. Flavonoid treatment often induced specific IgG antibodies and less frequently IgE antibodies. After short treatment IgE antibodies were more frequently detected than after treatment of longer duration which nearly always induced IgG antibodies. Patients with hemolysis had the highest IgG titers. In cases with fever and skin eruptions no correlation with antibody titers became evident. Antibody production in patients undergoing radiation therapy appeared to be lower than in non-irradiated patients. Both the IgE and IgG antibody test show a remarkable cross-reactivity between four different flavonoids. Prospective studies will be necessary to decide whether or not this method for the detection of anti-flavonoid antibodies will be suitable for recognizing increased risk of side reactions upon reexposure to flavonoid drugs.

Catechin↗
PubMed1986

Suppressive effects of B-lactam-antibiotics on in vitro generation of cytotoxic T-cells.

The in vitro effect of several compounds containing the B-lactam structure (including 6-aminopenicillanic acid, piperacillin, 7-aminocephalosporanic acid, ceftazidime and clavulanic acid) on the generation of cytotoxic lymphocytes was investigated in two different in vitro systems: (1) generation of virus specific cytotoxic T-cells and (2) proliferation of lymphocytes were assessed in secondary in vitro anti-viral immune responses. Both activities were suppressed by B-lactams in a dose-dependent manner. In these experiments, as found previously with human in vitro granulopoesis and proliferation of the human erythroleukaemic cell line K-562, cephalosporins and clavulanic acid were five to twenty times more suppressive than penicillins. Since concentrations that were effective in vitro are being achieved, particularly with cephalosporins, in the serum of patients, the possible clinical consequences of our findings may have to be taken into consideration.

Animals↗
PubMed1986

Measurement of specific IgG antibody levels in serum of patients on regimes comprising high total dose beta-lactam therapy.

Sera from 125 patients receiving mean total doses of beta-lactam therapy of 215 g over a mean of 14 days were assayed by radioimmunoassay. Titres of anti-penicilloyl antibodies, expressed in arbitrary units of specific IgG per microliter of serum (u/microliter), ranged from undetectable (less than 3 u/microliter) to 1,650 u/microliter. There was a higher prevalence of elevated IgG levels in patients who developed haemolytic anaemia or neutropenia compared with patients with no adverse reactions but only in those patients who developed haemolytic anaemia were the antibody titres significantly higher. A subsidiary finding was that a correlation was established between mean total dose and prevalence of positive IgG titres, on a patient group basis (r = 0.87).

Anemia, Hemolytic↗
PubMed1985

Inhibition of granulopoiesis in vivo and in vitro by beta-lactam antibiotics.

beta-Lactam antibiotics can induce severe neutropenia by a hitherto unknown mechanism. Fifty cases of beta-lactam antibiotic-induced neutropenia (less than 1,000 neutrophils/mm3) from 17 hospitals were analyzed and compared with 140 literature cases. The incidence of neutropenia was 5%-greater than 15% in patients treated for greater than or equal to 10 days with large doses of any beta-lactam antibiotic but less than 0.1% with shorter duration of therapy. In greater than 95% of cases recovery occurred between one to seven days after withdrawal of beta-lactam antibiotics. Bone marrow aspirates were characterized by a lack of well-differentiated myeloid elements in the presence of numerous immature granulocyte precursors. Nine penicillins and eight cephalosporins inhibited in vitro granulopoiesis in a dose-dependent manner. There was a good correlation between the inhibitory capacity of beta-lactam antibiotics in vitro and the doses inducing neutropenia in vivo. These observations may be relevant for therapy in the granulocytopenic patient.

Agranulocytosis↗
PubMed1985

Amoxicillin-induced immune hemolysis.

Severe hemolysis occurred in a 51-year-old female after a 17-day course of intravenous amoxicillin. A strongly positive direct antiglobulin test (anti-IgG titer 1:2,000) ensued which disappeared after withdrawal of the drug. Both the patient's serum and eluate obtained from the patient's red cells contained an IgG antibody which reacted with red blood cells coated in vitro with amoxicillin, but not with uncoated cells. In addition, high-titer antipenicillin, antiampicillin and antiamoxicillin IgG antibodies could be demonstrated in her serum by a RAST-based solid-phase radioimmunoassay. The patient's hemolysis gradually subsided within 1 week after discontinuing the drug. This is the first report of amoxicillin-induced immune hemolytic anemia.

Amoxicillin↗
PubMed1984

Adverse reactions following intravenous penicillin-G relate to degradation of the drug in vitro.

We have recently shown that high-dose intravenous therapy with penicillin-G always results in both sensitised lymphocytes and rise of anti-penicilloyl IgG antibodies. If penicillin-G is strictly given as freshly prepared bolus doses this sensitisation is prevented. In 193 patients, intravenous treatment with penicillin-G without special precautions (bolus doses stored up to 36 h at 4 degrees C or continuous infusions) led to 8.3% definite, 6.7% probable and 14.0% possible adverse reactions. In 116 patients treated exclusively with freshly dissolved doses, 0.9% definite, 1.7% probable and 4.3% possible reactions occurred. Whereas haemolytic anaemia (7) and neutropenia (12) were observed in 19 cases of the first group no such reactions were seen in the second group. Strict application of freshly prepared single doses prevents the majority of adverse reactions following highdose intravenous penicillin-G therapy. Degradation and transformation products formed in vitro are therefore the causative agents rather than the penicillin molecule itself.

Adolescent↗
PubMed1984

Different effects of selective and nonselective beta adrenoceptor blockade on urinary catecholamine and creatinine excretion in stress.

We tested the hypothesis that (1) beta 1-selective and nonselective beta adrenoceptor blockades have a different influence on stress-induced catecholamine overshoot, and (2) beta 1-selective blockade shifts the epinephrine/norepinephrine ratio in favor of norepinephrine. Seven violinists were investigated; each performed four times in public after ingesting different beta blockers. A significantly greater urinary norepinephrine/creatinine excretion was found with selective beta blockade than with nonselective. In addition during selective beta blockade creatinine excretion decreased significantly in comparison with nonselective blockade. This might be due to a higher concentration of circulating norepinephrine, stimulating alpha receptors in the renal vasculature.

Adrenergic beta-Antagonists↗
PubMed1983

Penicillin-G degradation products inhibit in vitro granulopoiesis.

38% of penicillin-G in solution decays at 20 degrees C within 24 h, 50% at 37 degrees C and 66% within 3 h at 56 degrees C. These degraded penicillin-G solutions strongly inhibit growth and maturation of granulocytic stem cells in vitro. Inhibitory concentrations are in the range obtainable with high dose penicillin therapy in vivo. No cytotoxicity of degraded penicillin solutions on bone marrow cells was seen over 24 h. It is suggested that penicillin-G degradation products are responsible for severe granulocytopenia observed after high dose penicillin-G therapy.

Bone Marrow↗