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Biomedical subjects

L Lind

Publications and source records attributed to L Lind.

224 records · Page 13Linked to original sources
PubMed1983

Binding between the par region of plasmids R1 and pSC101 and the outer membrane fraction of the host bacteria.

The binding between par+ and par plasmid DNA to different membrane fractions of Escherichia coli was investigated. Membrane material from cells carrying different Par+ and Par- derivatives of plasmids R1 and pSC101 was isolated and fractionated into an outer and a cytoplasmic membrane fraction. The presence of plasmid DNA in the two membrane fractions was measured either by nick-translation of the membrane-bound DNA, followed by filter-hybridization to homologous DNA, or by filter-hybridization of the membrane-bound DNA to nick-translated homologous purified plasmid DNA. The DNA of par derivatives of plasmids R1 and pSC101 could be detected only in the cytoplasmic membrane fraction, whereas the corresponding par+ plasmid DNA also appeared in the outer membrane material, indicating a specific binding between the R1 and pSC101 partition loci and the bacterial outer membrane. The experiment was then modified by fractionation of the membrane material from cells carrying hybrids between the vector pSF2124 and the par region or the basic replicon region of plasmid R1. The DNA of the membrane fractions were filter-hybridized to nick-translated probes. Again, the par+ region caused hybridization to the outer membrane material. Therefore, we may conclude that controlled partitioning involves binding of DNA to membrane material that has the same density as the outer membrane of the host bacteria. This finding offers a biochemical 'assay' for studies of the molecular biology of plasmid partitioning.

Binding Sites↗
PubMed1983

Antibiotic sensitivity of Haemophilus influenzae, Streptococcus pneumoniae, Streptococcus pyogenes and Branhamella catarrhalis isolated from upper respiratory tract infections in Sweden.

Isolates of Haemophilus influenzae, Streptococcus pneumoniae, Streptococcus pyogenes and Branhamella catarrhalis were collected from five laboratories in different geographical areas in Sweden. Nine hundred and fortyfour strains were tested by the agar dilution method for susceptibility to seven oral antibiotics: phenoximethylpenicillin, ampicillin, cefaclor, erythromycin, doxycycline, trimethoprim-sulfamethoxazole and chloramphenicol. The H. influenzae and B. catarrhalis strains were also tested for beta-lactamase production. Of the H. influenzae strains, 8% were beta-lactamase-producing, while 35% of B. catarrhalis strains produced beta-lactamase. The latter value is higher than has earlier been reported in Sweden. Five S. pneumoniae strains showed decreased sensitivity to penicillin, and 9.5% of the S. pneumoniae strains showed a decreased sensitivity to one or more of the seven antibiotics tested. The S. pyogenes strains were sensitive to all the antibiotics tested with the exception of 4% of the strains, which showed a decreased sensitivity to doxycycline.

Anti-Bacterial Agents↗
PubMed1983

The need for control of throat streptococcal cultures in general practice.

During recent years, it has become more and more common among general practitioners and pediatricians to inoculate and read agar plates for diagnosis of beta-hemolytic streptococci so that an accurate etiological diagnosis in cases of suspected tonsillitis can be made. As a control of the diagnostic quality, "unknown" streptococcal strains were distributed from the bacteriological laboratory to the practitioners performing this type of diagnostic procedure. The results show that the ability to correctly classify these strains varied greatly. Technical problems such as inadequate temperature control of relatively simple incubators were also found. Continuous education and information on beta-hemolytic streptococcal diagnostic procedures are important to ensure sufficient quality.

Agar↗
PubMedDate not supplied

Effects of digoxin, furosemide, enalaprilat and metoprolol on endothelial function in young normotensive subjects.

1. Endothelial dysfunction is seen in patients with essential hypertension or congestive heart failure (CHF). The present study aimed to evaluate the direct effect on endothelium- dependent vasodilation (EDV) of different pharmacological drugs commonly used in the treatment of these conditions. 2. Forearm blood flow (FBF) was measured in 37 young healthy normotensive subjects with venous occlusion plethysmography during local intra-arterial infusions of methacholine (MCh; 2-4 microg/min), evaluating EDV, and sodium nitroprusside (SNP; 5-10 microg/min), evaluating endothelium-independent vasodilation (EIDV). The measurements of EDV and EIDV were undertaken under baseline conditions and were repeated after 1 h intra-arterial infusion of digoxin (0.1 mg/h), furosemide (5.0 mg/h), enalaprilat (2,4 mg/h), metoprolol (1.2 mg/h) or saline (controls). 3. Enalaprilat and digoxin improved the FBF response to MCh at 4 microg/min (from 22.7+/-2.3 to 25.5+/-2.1 mL/min per 100 mL tissue (P < 0.01) and from 18.2+/-2.4 to 22.2+/-2.0 mL/min per 100 mL tissue (P < 0.05), respectively). No significant changes where induced by furosemide or metoprolol in response to MCh at 4 microg/min (from 19.4+/-2.0 to 22.9+/-2.8 and from 15.3+/-2.4 to 14.7+/-1.1 mL/min per 100 mL tissue, respectively). No significant changes in basal FBF or EIDV were induced by the different drugs. When the endothelial function index was calculated as the MCh: SNP FBF ratio, a significant improvement was seen only with enalaprilat (1.1+/-0.1 to 1.2+/-0.1; P < 0.01) and furosemide (1.0+/-0.1 to 1.3+/-0.4; P < 0.05). 4. In conlusion, the results of the present study show that enalaprilat and furosemide improve endothelial vasodilatory function, while no major effect was induced by digoxin or metoprolol. Thus, different direct effects on the endothelium in young normotensive subjects were induced by drugs commonly used in the treatment of hypertension or CHF.

Adolescent↗
PubMedDate not supplied

Relationships between endothelium-dependent vasodilation, serum vitamin E and plasma isoprostane 8-iso-PGF(2alpha) levels in healthy subjects.

Due to the reported associations between a low intake of vitamin E and atherosclerosis on one hand, and between endothelial dysfunction and atherosclerosis on the other hand, we investigated the relationship between endothelium-dependent vasodilation and serum levels of vitamin E (alpha- and gamma-tocopherol) as well as the lipid peroxidation markers malondialdehyde and 8-iso-PGF(2alpha) in a healthy population. Healthy subjects (31 men and 25 women), aged between 20 and 69 years, underwent measurements of forearm blood flow (FBF) at rest and during local infusion of 2 and 4 microg/min of methacholine (Mch, to evaluate endothelium-dependent vasodilation) and 5 and 10 microg/min of sodium nitroprusside (SNP, to evaluate endothelium-independent vasodilation, and during reactive hyperemia using venous occlusion plethysmography. Serum alpha-tocopherol concentration was significantly related to the index of endothelial function (r = 0.46, p < 0.01), defined as the ratio between the maximal dilatations during Mch and SNP infusions. Serum gamma-tocopherol levels were positively related to the maximal FBF during reactive hyperemia (r = 0.54, p < 0.01) in women only. Furthermore, in women only, plasma 8-iso-PGF(2alpha) levels were inversely related to the relative increases in FBF during both Mch and SNP infusions (r = -0.58 and r = -0.59, p < 0.01 for both). The results show a relationship between the levels of alpha-tocopherol and endothelial vasodilatory function, suggesting a beneficial role for this potent lipid-soluble antioxidant also in a population sample of apparently healthy subjects. Furthermore, in women, the accumulation of lipid peroxidation products such as 8-iso-PGF(2alpha) seems to be associated with an impaired vasodilation in general.

Adult↗
PubMedDate not supplied

Corticosteroid suppression of trauma-induced hyaluronan in rabbit cornea and aqueous.

BACKGROUND: Corneal and aqueous hyaluronan have recently been shown to react in response to several different types of trauma, including cataract surgery. In order to find ways to influence the reaction, we have evaluated the effect of topical dexamethasone (Isopto-Maxidex, Alcon Universal Ltd, Fort Worth, Tex) or indomethacin (Confortid, Dumex Ltd, Copenhagen, Denmark) on the postoperative hyaluronan concentration in rabbit cornea and aqueous after extracapsular lens extraction. METHODS: The drugs were administered as topical eye drops three times daily. The hyaluronan concentration in rabbit cornea and aqueous after extracapsular lens extraction was measured with a radioligand assay. RESULTS: Dexamethasone treatment (1 mg/mL) significantly suppressed the increase in corneal hyaluronan seen after extracapsular lens extraction, 2 (p < or = 0.0022) and 3 weeks (p < or = 0.0002) after surgery, while indomethacin did not induce any significant difference at 2 weeks. When the dexamethasone concentration was lowered to 0.1 and 0.2 mg/mL, there was still a significant decrease (p < or = 0.009) in hyaluronan concentration, but at lower concentrations of dexamethasone (0.01 and 0.02 mg/mL), no significant decrease was seen. The increase in aqueous hyaluronan concentration seen 2 days after surgery in untreated eyes was significantly lowered by both dexamethasone (p < or = 0.0076) and indomethacin (p < 0.036). CONCLUSIONS: Dexamethasone lowers reactive corneal and aqueous hyaluronan concentration in vivo after extracapsular lens extraction.

Administration, Topical↗