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Biomedical subjects

A Forsgren

Publications and source records attributed to A Forsgren.

At least 91 records · Page 5Linked to original sources
PubMed1989

Overview of Scandinavian in vitro studies with ciprofloxacin.

Scandinavian studies have confirmed that ciprofloxacin is highly active against most Gram-negative bacterial species with extremely low minimal inhibitory concentrations (MIC-values) except for Pseudomonas aeruginosa. The antibacterial activity is approximately four times higher than that of norfloxacin. Gram-positive cocci are less sensitive with MIC-values of 0.5 to 1 mg/l. For pneumococci the ciprofloxacin concentration inhibiting 90% of clinical isolates (MIC90) is approximately 2 mg/l. The antibacterial activity of ciprofloxacin is influenced very little by an increased inoculum and culture conditions. However, urine reduces the antibacterial activity. Resistance to ciprofloxacin occurs extremely rarely among E. coli, but development of resistance among species like P. aeruginosa and Staphylococcus aureus may be more frequent. Ciprofloxacin is a bacterial antibiotic but killing of staphylococci was poor when studied kinetically. Ciprofloxacin plus piperacillin act synergistically against strains of P. aeruginosa. Ciprofloxacin has a post-antibiotic effect (PAE) of approximately 2h against both Gram-negative rods and Gram-positive cocci.

Bacteria↗
PubMed1989

Effect of ciprofloxacin on human lymphocytes--laboratory studies.

4-Quinolones affect mammalian cellular functions in vitro in several ways. Inhibition of cell proliferation differ widely among 4-quinolones. Ciprofloxacin is one of the most antiproliferative inhibiting cell growth with about 30% at 20 mg/l. Genotoxicity tests with 4-quinolones are probably "false" positive due to an increased [3H]-thymidine uptake not related to DNA damage. Ciprofloxacin at 10 mg/l and up causes significant DNA strand breaks which seemingly are quickly repaired and not causing mutations or cancerogenesis. Ciprofloxacin at 5 mg/l inhibits immunoglobulin production but the growth factor interleukin 2 (IL-2) is increased by 4-quinolones at the same concentration and hyperinduced at higher concentrations. Thus the effects are very contradictory. Increased IL-2 may contribute to CNS side effects.

Ciprofloxacin↗
PubMed1989

Use of ciprofloxacin in patients undergoing transurethral prostatic surgery.

The efficacy of a short (Group I) and a prolonged (Group II) course with ciprofloxacin was assessed in patients undergoing transurethral prostatic resection and compared with that of controls without antibiotic (Group III). Both regimens significantly reduced the frequency of post-operative bacteriuria (p less than 0.01) and of severe infectious complications (p = 0.004) compared to the controls. Both regimens were equally effective in preventing peri-operative and post-operative acquisition of bacteriuria in patients without bacteriuria at surgery. In patients with bacteriuria before surgery, bacteriuria was found post-operatively in 35% in Group I and in 9% in Group II (p = 0.012), but in 82% of the patients in Group III. Ciprofloxacin inhibited all but 7 of 176 bacterial strains at an MIC of less than or equal to 1 microgram/ml. Given orally, ciprofloxacin is a valuable alternative antimicrobial for use in conjunction with transurethral prostatic resection. A short course is sufficient for prophylaxis, and adequate therapy is achieved with a prolonged regimen.

Bacterial Infections↗
PubMed1988

Role of the 2H4 molecule in the activation of suppressor inducer function.

The monoclonal antibody anti-2H4 recognizes a 220-kDa and 200-kDa glycoprotein and subdivides T4+ cells into distinct subpopulations: the T4+2H4+ inducer of suppression and the T4+2H4- inducer of help. The T4+2H4+ subset has been shown to play a crucial role in the activation of T8+ suppressor cells. In the present study, we attempted to determine whether the 2H4 molecule itself may be involved in initial triggering of suppressor inducer function. The results show that the addition of anti-2H4 antibody to a mixture of B and T cells resulted in a marked suppression of pokeweed mitogen-driven Ig synthesis. When anti-2H4 was added to B cell cultures containing T4+2H4+ or T4+2H4- cells but lacking T8 cells, no suppression was generated. In addition to the requirement for T8 cells, no suppression was generated if T4+2H4+ cells were absent. These results suggest that the anti-2H4 antibody contributes to the activation of the T4+2H4+ lymphocyte subset, which in turn induces T8 cells to suppress B cell Ig synthesis. Biochemical analysis of the T4+2H4+ subset of lymphocytes indicated that the in vitro addition of anti-2H4 antibody resulted in an increased expression of the 220-kDa and 200-kDa structure on T4 cells. We conclude that perturbation of the 2H4 molecule may potentiate the activation of the suppressor inducer subset and that the T200 molecule may be directly involved in suppressor inducer function.

Antibodies, Monoclonal↗
PubMed1988

Branhamella catarrhalis activates human B lymphocytes following interactions with surface IgD and class I major histocompatibility complex antigens.

Branhamella catarrhalis initiated DNA synthesis in human blood or spleen cells enriched for B lymphocytes but did not activate T-lymphocyte-enriched fractions. Monoclonal antibodies were used to determine which B-cell surface molecules were of importance for the activation signal. The addition of monoclonal antibodies reactive with IgD, HLA class I antigens, and B2-microglobulin to B lymphocyte cultures selectively inhibited the B-lymphocyte response to B. catarrhalis. Antibody binding to IgD and class I antigens did not inhibit B-cell proliferation following stimulation with anti-IgM beads, Staphylococcus aureus, or Epstein-Barr virus. This suggests that surface IgD is of major importance for B-lymphocyte stimulation by B. catarrhalis. Since B. catarrhalis binds HLA-ABC containing liposomes it is suggested that a similar binding of B. catarrhalis to HLA-ABC on the surface of B lymphocytes serves as an accessory factor that stabilizes the binding of B. catarrhalis to surface IgD. Activation of human B lymphocytes by B. catarrhalis resulted in changes of cell surface molecules that were quantitatively and qualitatively similar to those that resulted from the activation by S. aureus. Therefore although these two bacteria appear to activate B cells in a similar manner, they induce B-cell proliferation through interactions with different cell surface structures.

Adult↗
PubMed1988

In vitro selection of Escherichia coli mutants with decreased susceptibility to norfloxacin.

In 10 clinical isolates of Escherichia coli the frequency of spontaneous mutation to high levels of resistance to nalidixic acid was greater than 300-fold higher than that to norfloxacin. Norfloxacin resistant mutants could not be detected (mutation frequency: less than 10(-12). However, nalidixic acid resistant mutants of E. coli developed decreased susceptibility to norfloxacin at a rate of approximately 10(-9). Mutants with decreased susceptibility to norfloxacin could also be obtained when the same clinical isolates of E. coli were exposed to norfloxacin in 2 steps. However, mutants with MIC values greater than 8 micrograms/ml for norfloxacin were never obtained even after repeated exposure. Widespread use of cinoxacin or nalidixic acid may select resistant strains and reduce the efficacy of norfloxacin and other 4-quinolones.

Drug Resistance, Microbial↗
PubMed1988

Significance of group B streptococci in urine cultures from males and non-pregnant females.

Over a 2-year period, 1% of 24,000 urine cultures with possible relevant bacteria from males and non-pregnant females greater than or equal to 15 years of age were found to harbour group B streptococci (GBS) in quantities greater than or equal to 10(5) colony forming units (cfu)/ml; a further 0.9% harboured GBS in quantities greater than or equal to 10(4) but less than 10(5) cfu/ml. Patients with GBS in urine were evenly distributed by age. Those with greater than or equal to 10(5) cfu GBS/ml in voided urine more frequently had true bacteriuria (i.e. bacteria in the urine bladder) than did patients with less amounts (p = 0.01) as determined by suprapubic aspiration of 23 patients. One third (3/9) of the aspirated patients with greater than or equal to 10(5) cfu GBS/ml in simultaneously voided urine, had contaminated urine only and no true bacteriuria. The acute symptoms and clinical conditions of 128 patients with greater than or equal to 10(5) cfu GBS/ml urine were studied by matching 128 patients with negative urine cultures (less than 10(2) cfu/ml) and 128 patients with comparable quantity of Escherichia coli. The incidence of acute lower urinary tract symptoms in patients with GBS was greater than that in patients with negative urine cultures (p less than 0.01), and the same as that in patients with E. coli. The incidence of fever was lower in patients with GBS than in those with E. coli (p less than 0.01). The incidence of urinary tract abnormalities was greatest in patients with GBS in urine. No GBS serotype seems to have particular affinity to the urinary tract.

Adolescent↗
PubMed1988

Long-term effects on bacterial sensitivity patterns of preoperative antibiotic prophylaxis in colorectal surgery.

Since 1973, when doxycycline was introduced as preoperative prophylaxis in elective colorectal surgery at Malmö General Hospital, Sweden, there has been an unchanged and low rate (8% to 12%) of septic complications in colonic surgery. For treatment of postoperative infections, ampicillin and cefuroxime have been used since 1973 and 1980, respectively. The sensitivity of Escherichia coli to these three antibiotics used for prophylaxis and treatment was followed for five years (1981-1985). Only minor changes were observed during the period. A lower frequency of antibiotic resistance was found in bacterial strains isolated peroperatively than in strains isolated postoperatively after colorectal surgery or from infections in other patients. Considering the low frequency of postoperative infectious complications and the low frequency of antibiotic resistance in peroperative isolates, doxycycline still remains an alternative for prophylaxis in bowel surgery.

Anti-Bacterial Agents↗
PubMed1987

Controlled trial of a short and a prolonged course with ciprofloxacin in patients undergoing transurethral prostatic surgery.

The efficacy of a short (Group I) and a prolonged (Group II) course with ciprofloxacin was assessed in patients undergoing transurethral prostatic resection for benign hyperplasia or cancer of the prostate and compared with that of controls without antibiotic (Group III). Both regiments significantly reduced the frequency of postoperative bacteriuria (p less than 0.01) and of severe infectious complications (p = 0.004) as compared to the controls. Both regimens were equally effective in preventing perioperative and postoperative acquisition of bacteriuria in patients without bacteriuria at surgery. In patients with bacteriuria before surgery, bacteriuria was found postoperatively in 35% in Group I and 10% in Group II (p = 0.012), but in 82% of the patients in Group III. Ciprofloxacin inhibited all but 7 of 176 bacterial strains at an MIC of less than or equal to 1 microgram/ml. Given orally ciprofloxacin is a valuable alternative antimicrobial for use in conjunction with transurethral prostatic resection. A short course is sufficient for prophylaxis, and adequate therapy is achieved with a prolonged regimen.

Aged↗
PubMed1987

Evaluation of culture methods for isolation of group B streptococci.

Attempts were made to isolate group B streptococci (GBS) from 382 urethral and 140 rectal specimens by overnight incubation in three variants of Todd Hewitt broth, followed by subculture on human blood agar plates. All three broths prepared contained 5% sheep blood, but one contained no antibiotics (THB), while the other two contained gentamicin and nalidixic acid at concentrations of 0.8 microgram/ml and 1.5 micrograms/ml (THBL), and 8 micrograms/ml and 15 micrograms/ml (THBH), respectively. THBL gave the highest isolation frequency both for urethral and rectal specimens. While THBH was superior to THB for isolating GBS in rectal specimens, for urethral samples they were equally effective. Direct plating of 154 specimens on blood agar was less effective than was enrichment in any of the three broths followed by plating on blood agar.

Culture Media↗
PubMed1987

4-Quinolone drugs affect cell cycle progression and function of human lymphocytes in vitro.

Most antibacterial agents do not affect human lymphocyte function, but a few are inhibitory. In contrast, a pronounced increase in the incorporation of [3H]thymidine in the presence of 4-quinolones was observed in these studies. The uptake of [3H]thymidine into DNA (trichloroacetic acid precipitable) was significantly increased in phytohemagglutinin-stimulated human lymphocytes when they were exposed to eight new 4-quinolone derivatives, ciprofloxacin, norfloxacin, ofloxacin, A-56619, A-56620, amifloxacin, enoxacin, and pefloxacin, at 1.6 to 6.25 micrograms/ml for 5 days. Four less antibacterially active 4-quinolones (nalidixic acid, cinoxacin, flumequine, and pipemidic acid) stimulated [3H]thymidine incorporation only at higher concentrations or not at all. Kinetic studies showed that incorporation of [3H]thymidine was not affected or slightly inhibited by ciprofloxacin 2 days after phytohemagglutinin stimulation but was increased on days 3 to 6. The total incorporation of [3H]thymidine from day 1 to day 6 after phytohemagglutinin stimulation was increased by 42 to 45% at 5 to 20 micrograms of ciprofloxacin per ml. Increased [3H]thymidine incorporation was also seen when human lymphocytes were stimulated with mitogens other than phytohemagglutinin. Ciprofloxacin added at the start of the culture had a more pronounced effect on [3H]thymidine incorporation than when added later. In spite of the apparent increase in DNA synthesis, lymphocyte growth was inhibited by 20 micrograms of ciprofloxacin per ml, and cell cycle analysis showed that ciprofloxacin inhibited progression through the cell cycle. In addition, immunoglobulin secretion by human lymphocytes stimulated by pokeweed mitogen for Epstein-Barr virus was inhibited by approximately 50% at 5 micrograms of ciprofloxacin per ml. These results suggest that the 4-quinolone drugs may also affect eucaryotic cell function in vitro, but additional studies are needed to establish an in vivo relevance.

Anti-Infective Agents↗
PubMed1987

Effects of ciprofloxacin on eucaryotic pyrimidine nucleotide biosynthesis and cell growth.

Several of the new 4-quinolones significantly increase the incorporation of [3H]thymidine into the DNA of mitogen-stimulated human lymphocytes. This study suggests that ciprofloxacin inhibits de novo pyrimidine biosynthesis, thereby resulting in a compensatory increase in the uptake of pyrimidine precursors through salvage pathways, and that additional effects may affect eucaryotic cell growth. Incorporation of deoxyuridine, uridine, and orotic acid as well as thymidine was increased in the presence of ciprofloxacin, one of the antibacterially most active of the new 4-quinolones. In contrast, the uptake was decreased in very high concentrations of the drug. Culture in HAT (hypoxanthine, aminopterine, thymidine) medium, which blocks de novo thymidylate synthesis, abrogated the increase in [3H]thymidine incorporation induced by ciprofloxacin. Ciprofloxacin also failed to increase the uptake of [14C]hypoxanthine or leucine, indicating a selective effect on pyrimidine and not on purine nucleotide biosynthesis. N-(Phosphonacetyl)-L-aspartate, an inhibitor of pyrimidine nucleotide biosynthesis, also increased [3H]thymidine incorporation in phytohemagglutinin-stimulated lymphocytes in a fashion similar to ciprofloxacin. The growth of several cell lines was partially inhibited by ciprofloxacin at 20 micrograms/ml and completely inhibited at 80 to 160 micrograms/ml. Growth inhibition by ciprofloxacin could not be restored by the addition of uridine to the medium. Chromosome breaks, gene amplification, or other genetic alterations could not be detected in human lymphocytes incubated with up to 25 micrograms of ciprofloxacin per ml.

Animals↗
PubMed1987

3,4-Dihydroxypyridine: a potential antithyroid drug.

3,4-Dihydroxypyridine (3,4-DHP), a goitrogenic derivative of the plant amino acid mimosine, has no SH-group, in contrast to conventional antithyroid agents such as methimazole (MMI) and propylthiouracil (PTU). The current in vitro study shows that 3,4-DHP, like MMI and PTU, inhibits iodination of human thyroglobulin and interferes with mitogenic activation of human lymphocytes. This, together with a very low murine bone marrow toxicity, probably related to the absence of an SH-group, makes 3,4-DHP a potential antithyroid drug.

Antithyroid Agents↗
PubMed1987

Longitudinal study of group B streptococcal carriage during late pregnancy.

152 women were cultured for group B streptococci (GBS) weekly from the 37th week of gestation and at admission to hospital for delivery. Matched rectal, urethral and urine specimens were collected for study (mean 4 times). In the 37th week of gestation, 33 women (22%) harboured GBS in rectal specimens, 28 women (18%) in urethral specimens, 16 women (11%) in urine specimens, and 37 women (24%) in at least one of the 3 specimens. All cultures considered, a total of 46 women (30%) yielded GBS in at least one culture. In the 37th week of gestation, women subsequently found to be GBS colonized at labour (positive in at least one site) had a higher rate of positive cultures in rectal specimens (77%) than in either urethral (67%) or urine specimens (41%). Chronic GBS carriage was more frequent in rectum than in urethra or urine. The results of the present investigation support the gastrointestinal tract as being the predominant source of GBS.

Bacteriological Techniques↗
PubMed1987

Pneumonia and acute pancreatitis most probably caused by a Legionella longbeachae infection.

Legionella longbeachae was first described and characterized in 1981. We report the first probable case of L. longbeachae infection in Sweden. A previously healthy, 50-year-old greenhouse repairman fell ill with severe pneumonia and acute pancreatitis. The L. longbeachae type 1 IgG titer (indirect immunofluorescence) was 256 and decreased significantly with erythromycin treatment. Attempts to isolate the microorganism from the environment failed. Sera from the patient's colleagues and from blood donors all had antibody titers of less than 32.

Acute Disease↗
PubMed1987

A sulfhydryl-rich IgM protein with multiple serological specificities.

A monoclonal IgM lambda protein from a patient (E.T.) suffering from a lymphocytic lymphoma agglutinated Salmonella typhi bacteria and uncoated acryl particles. The antigenic determinant on Salmonella typhi bacteria was found to be 0-12 (alpha-D-Galp-(1-2)-alpha-D-Manp) while the structure on acryl particles recognized by IgM ET has not been defined. Both binding sites for bacteria and acryl particle determinants are localized on the same IgM molecule. The uncommon affinity of this IgM protein for some divalent heavy metal ions led to the finding of an unusually high content of sulfhydryl groups in the Fab portion of the molecule.

Acrylates↗