Novel mouse model of chronic Pseudomonas aeruginosa lung infection mimicking cystic fibrosis

Pseudomonas aeruginosa causes a chronic infection in the lungs of cystic fibrosis (CF) patients by establishing an alginate-containing biofilm. The infection has been studied in several animal models; however, most of the models required artificial embedding of the bacteria. We present here a new pulmonary mouse model without artificial embedding. The model is based on a stable mucoid CF sputum isolate (NH57388A) with hyperproduction of alginate due to a deletion in mucA and functional N-acylhomoserine lactone (AHL)-based quorum-sensing systems. Chronic lung infection could be established in both CF mice (Cftr(tmlUnc-/-)) and BALB/c mice, as reflected by the detection of a high number of P. aeruginosa organisms in the lung homogenates at 7 days postinfection and alginate biofilms, surrounded by polymorphonuclear leukocytes in the alveoli. In comparison, both an AHL-producing nonmucoid revertant (NH57388C) from the mucoid isolate (NH57388A) and a nonmucoid isolate (NH57388B) deficient in AHL were almost cleared from the lungs of the mice. This model, in which P. aeruginosa is protected against the defense system of the lung by alginate, is similar to the clinical situation. Therefore, the mouse model provides an improved method for evaluating the interaction between mucoid P. aeruginosa, the host, and antibacterial therapy.     

Imprint cytology in immunocytochemical analysis of oestrogen and progesterone receptors of breast carcinoma.

Cytological imprint material from 26 mammary carcinomas was stained with monoclonal antibodies to oestrogen and progesterone receptors in an immunoperoxidase procedure. The staining result was compared with that of parallel stainings of frozen tissue sections of the same tumours. The peroxidase reactions in both techniques were semiquantitatively assessed (histoscore). In both sets of stainings the results agreed in 25 of 26 cases (oestrogen receptor: 19 positive, six negative; progesterone receptor: 14 positive, 11 negative). The histoscores of imprint preparations and cryostat sections showed a significant correlation in linear regression analysis (oestrogen receptor: r = 0.755, p less than 0.001; progesterone receptor: r = 0.740, p less than 0.001). Imprint cytology is simple, does not require expensive instruments, and no separate specimen has to be sequestered. It is especially suitable for immunocytochemical steroid receptor analysis of small breast carcinomas.     

Comparison of two urinary antigen tests for establishment of pneumococcal etiology of adult community-acquired pneumonia

The Binax NOW immunochromatographic test (ICT) detecting the pneumococcal C polysaccharide and a serotype-specific latex agglutination (LA) test detecting 23 pneumococcal capsular antigens were evaluated for establishing pneumococcal etiology in community-acquired pneumonia (CAP) by use of nonconcentrated urine. ICT was considered to be strongly positive for result lines at least as intense as the control line and weakly positive for less intense result lines. When 215 adult CAP patients were tested, strong ICT, weak ICT, and LA positivity were found in 28, 24, and 16 patients, respectively; of these patients, 13 (46%), 6 (25%), and 13 (81%), respectively, had pneumococcal bacteremia and 27 (96%), 17 (71%), and 15 (94%), respectively, had Streptococcus pneumoniae isolated from blood, sputum, and/or nasopharynx. Among 108 controls tested, 2 (1.9%) were weakly ICT positive. When weak positivity was considered negative, the sensitivity of ICT decreased from 79% (19 of 24) to 54% (13 of 24), while the specificity increased from 83% (158 of 191) to 92% (176 of 191); no controls were false positive. The sensitivity and specificity of LA were 54% (13 of 24) and 98% (188 of 191), respectively. Eight of nine LA serotypes corresponded to culture serotypes. In conclusion, using nonconcentrated urine and dividing ICT-positive results into strongly and weakly positive results is a suitable way of performing ICT. While weak ICT positivity should be interpreted with caution, strong ICT positivity and LA positivity should be considered supportive of pneumococcal etiology in adult CAP. As such, these assays might have implications for antibiotic use in CAP. LA has promising potential for pneumococcal serotyping, although further evaluation is required.     

Comparison of the effects of recombinant interleukin 6 and recombinant interleukin 1 on nonspecific resistance to infection

Interleukin 1 (IL 1) is a potent enhancer of nonspecific resistance to infection in mice. Since IL 1 also induces interleukin 6 (IL 6), we tested the hypothesis that IL 6 mediates the effect of IL 1 on nonspecific resistance. In a lethal Pseudomonas aeruginosa infection in granulocytopenic mice, in which 80 ng of recombinant human IL 1 alpha protects against death, IL 6 appeared to be much less effective. Dosages of 8 ng, 80 ng and 320 ng IL 6 did not differ from the control, whereas 800 ng had a marginal protective effect (0.05 less than p less than 0.1). IL 1 and IL 6 did not potentiate each other in animals treated with suboptimal dosages of both cytokines. Numbers of bacteria cultured from the blood, thigh muscle, liver, spleen, and kidney were similar in animals treated with 800 ng IL 6 and in control animals, arguing against activation of microbicidal mechanisms. The serum concentration profile of IL 6 after an i.p. injection of 80 ng IL 1 was similar to that after 80 ng IL 6 i.p. Only minute amounts of IL 1 were detected in serum after an i.p. injection of IL 6. Taken these data together, it appears that increased resistance to infection induced by IL 1 is not mediated by IL 6.     

Immunocytochemical detection of estrogen and progesterone receptors in 124 human breast cancers

Monoclonal antibodies to human estrogen receptor (ER), and rabbit progesterone receptor (PR), also recognizing human PR, were used to detect the receptors by peroxidase immunocytochemistry in frozen sections of 124 primary breast carcinomas. Both ER and PR were almost exclusively located in carcinoma cell nuclei, with heterogeneous distribution and intensity. The staining results were evaluated semiquantitatively (histoscore), based on the percentage of positively stained carcinoma cells and nuclear staining intensity. The receptor status thus determined was as follows: ER+PR+ in 50 patients, ER+PR- in 23, ER-PR- in 26, and ER-PR+ in 3 patients. There was a 79% (ER) or 70% (PR) agreement in the positivity/negativity between the immunocytochemical and steroid-binding assay (in 102 patients) with a highly significant correlation. The histoscore values increased significantly with cytosol receptor levels (ER, r = 0.623, P less than 0.001; PR, r = 0.366, P less than 0.01).     

Proliferative activity and steroid receptors determined by immunohistochemistry in adjacent frozen sections of 102 breast carcinomas

Adjacent frozen sections of 102 consecutive female breast carcinomas were examined for the expression of the Ki-67 antibody-reactive proliferation-associated nuclear antigen and of estrogen and progesterone receptors with the use of monoclonal antibodies and peroxidase histochemistry. The results of steroid receptor stainings were semiquantitatively assessed (histoscore) on the basis of nuclear staining intensity and the percentage of positively stained carcinoma cell nuclei. Carcinomas negative for either receptor had significantly higher percentages of Ki-67-positive cells. The highest percentages of Ki-67-positive cells were observed in carcinomas negative for both estrogen and progesterone receptors. There was a highly significant decrease in receptor histoscores with increasing proliferative cell fractions as determined by Ki-67 positivity. No significant (progesterone receptor) or poor negative correlation (estrogen receptor) was observed when proliferative cell fractions were related to receptor concentrations from conventional steroid-binding assays. Immunoperoxidase staining for the Ki-67 antibody-defined proliferation antigen and steroid receptors in tissue sections provides a simple means to gain information of therapeutic and prognostic importance.     

Application of molecular and cytogenetic techniques to the detection of a de novo unbalanced t(11q;21q) in a patient previously diagnosed as having monosomy 21

Hertz B, Brandt CA, Petersen MB, Pedersen S, König U, Strømkjær H, Jensen PKA. Application of molecular and cytogenetic techniques to the detection of a de novo unbalanced t(11q;21q) in a patient previously diagnosed as having monosomy 21.
Clin Genet 1993: 44: 89–94. © Munksgaard, 1993
The occurrence of complete autosomal monosomy in man is extremely rare and generally considered to be incompatible with life. Since the introduction of banding techniques in human cytogenetics, several cases of presumptive monosomy for chromosome 21 have nevertheless been reported. However, it has been suggested that most, if not all, of these cases may represent unbalanced translocations or other structural aberrations resulting in only partial monosomy 21. Here we describe a patient in whom full monosomy 21 was initially diagnosed by routine karyotyping. Re-examination with a combination of high resolution banding technique, chromosome painting and DNA polymorphism analysis demonstrated the presence of an unbalanced translocation between the long arms of chromosome 11 and 21, respectively. Consequently, the case was re-classified as a partial monosomy for the proximal long arm of chromosome 21.     

Chromogranin A: osmotically active fragments and their susceptibility to proteolysis during lysis of the bovine chromaffin granules

Osmotically active fragments of chromogranin A (Chr A) were studied in lysates from bovine chromaffin granules (CG) disrupted in the presence or absence of inhibitors of endogenous proteolytic activities. The effects of various methods of lysis were examined by micro-osmometry, PAGE-SDS electrophoretic techniques and immunoblots with polyclonal anti-Chr A sera. Osmotically active 'small' Chr A fragments (below 30 kDa) were conspicuous in lysates containing cocktails of leupeptin, pepstatin A, pHMB, PMSF and aprotinin. The osmotically inactive native Chr A in the 68-100 kDa range and the osmotically active fragments below 47 kDa were degraded in lysates at neutral or acid pH in the absence of inhibitors. However, degradation of the native Chr A and intermediates below 47 kDa could be prevented by extraction directly from intact CG, notably in cold or boiling distilled water. On the other hand, the main product after large-scale extraction of CG in 1 M acetic acid (pH 1.9, 100 degrees C) was a novel, osmotically active fragment (22 kDa), immunostaining only for the N-terminal sequence (Chr A1-40). The heat-stable fraction (Mr,n 23 kDa) exhibited concentration-independent colloid osmotic pressures even in the absence of phosphate, a property which may distinguish this N-terminal-containing fragment from the larger intermediates, probably containing the pancreastatin sequence, and other regions at the C-terminal side of the prohormone molecule. The functional roles of these osmotically active intermediates in the processing of Chr A are not yet known.     

Drug Delivery Studies in Caco-2 Monolayers. Synthesis,Hydrolysis, and Transport of O-Cyclopropane Carboxylic Acid Ester Prodrugs of Various β-Blocking Agents

A series of O-cyclopropane carboxylic acid ester prodrugs of various -blocking agents was synthesized. All prodrugs were hydrolyzed to give their parent compounds in aqueous phosphate buffer of pH 7.4 and in 80% human plasma. The half-lives in buffer solutions varied from 4 hours for the timolol prodrug to about 1 day for the prodrug of alprenolol. In human plasma the half-lives were shorter, ranging from 1 to 7 hours. The formation of the O-cyclopropane carboxylic acid ester derivatives significantly increased the lipophilicities of the -blockers as measured by the distribution coefficient between n-octanol and aqueous phosphate buffer of pH 7.4. To characterize the biomembrane permeability characteristics of the -blockers, transport properties across Caco-2 cell monolayers were investigated. An increase in lipophilicity resulted in a higher permeability of the prodrugs as compared to the parent compounds. Hence, acebutolol experienced an increment of a factor 17 on the apparent permeability coefficient, Papp, whereas Papp for the more lipophilic drug propranolol was increased by a factor of only 1.26. Some conversion of the prodrugs to their parent compounds was observed during the transport and appeared to be due to enzymatic intracellular metabolism.Deseaced.