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Biomedical subjects

C Rich

Publications and source records attributed to C Rich.

At least 37 records · Page 2Linked to original sources

Deferred compensation for tax-exempt entities.

Many executives in tax-exempt organizations, including healthcare executives, find their tax-advantaged savings opportunities dramatically reduced today compared to previous years. The benefit of employer-sponsored, "qualified" retirement and savings programs has been severely limited by ever-increasing tax restrictions on such plans when they are offered by tax-exempt organizations. And the opportunity for tax-sheltered personal investments has virtually disappeared. One of the last remaining opportunities for tax-advantaged savings in tax-exempt organizations is an employer-sponsored, non-qualified, deferred compensation plan, an option that appears increasingly attractive in light of the recently enacted increased personal tax rates.

Financial Management↗

R-plasmid-encoded adhesive factor in Klebsiella pneumoniae strains responsible for human nosocomial infections.

Klebsiella pneumoniae strains involved in hospital outbreaks of nosocomial infections, such as suppurative lesions, bacteremia, and septicemia, were resistant to multiple antibiotics including broad-spectrum cephalosporins. Epidemiologic investigations revealed that the reservoir for these K. pneumoniae strains was the gastrointestinal tracts of the patients. The study of the adherence ability of the strains reported here showed that these bacteria adhered to the microvilli of the Caco-2 cell line. This adhesion was mediated by a nonfimbrial protein with a molecular mass of 29,000 Da designated CF29K. Pretreatment of bacteria with antibodies raised against CF29K or Caco-2 cells with purified CF29K prevented the adhesion of K. pneumoniae strains to Caco-2 cells. CF29K immunologically cross-reacted with the CS31A surface protein of Escherichia coli strains involved in septicemia in calves. Genes encoding CF29K were located on a high-molecular-weight conjugative R plasmid, which transferred to E. coli K-12. Transconjugants expressed a large amount of CF29K protein and adhered to the brush border of Caco-2 cells. These findings show that K. pneumoniae strains were able to colonize the human intestinal tract through a plasmid-encoded 29,000-Da surface protein. Hybridization experiments indicated that the gene encoding resistance to broad-spectrum cephalosporins by the production of CAZ-1 enzyme and the gene encoding the adhesive property to intestinal cells were both located on a 20- to 22-kb EcoRI restriction DNA fragment. Genes encoding aerobactin and the ferric aerobactin receptor were also found on this R plasmid.

Bacterial Adhesion↗

Peri-operative colonoscopy detects synchronous tumours in patients with colorectal cancers.

The aim of this study was to assess the value of colonoscopy as a peri-operative investigation in patients treated for colorectal cancer by surgical excision. Patients (134 male, 83 female) undergoing curative resection for colorectal carcinoma between August 1984 and January 1989 had colonoscopy within 3 months of surgery. Eleven patients (5%) had a synchronous cancer, which was diagnosed by colonoscopy in eight. In six of these eight, the diagnosis was made after surgery and 3 patients needed a second colectomy. However, in 3 patients the synchronous cancer was removed endoscopically without the need for further surgical resection. Most synchronous cancers had an earlier pathological stage than the index tumour. The rate of synchronous cancers was higher in patients with synchronous benign polyps (16%) than in those without polyps (3%). Colonoscopy is clearly justified as a peri-operative investigation in all patients undergoing potentially curative resection of colorectal cancer. If possible, the examination should be carried out prior to surgery, to guide the extent of resection.

Adult↗

[Factors intervening in the variations of in vitro adhesion power of enterotoxinogenic colibacillus (ETEC) to human enterocytes].

Human enterotoxigenic Escherichia coli adhere to the brush border of human enterocytes. The mean number of bacteria adhering to one enterocyte (adhesion index) varied from 0.5 to 3.1 when the strains produce adhesins. Different factors related to enterocytes and to bacteria are involved in this variability. The number of bacteria which adhered to enterocytes issued from the same donor varied from from 0 to 12. Moreover the proportion of enterocytes on which several bacteria sticked did not exceed 20%. This variability might be due to the disparity in the maturation of the enterocytes. On the other hand, whatever the adhesion factors considered, the adhesion index varied according to the donors. ETEC strains did not express adhesion when bacteria were grown in a liquid medium but this capacity could be restored after transfer on solid medium. This phenomenon seemed like a phase-variation and appeared to be linked to a 4 to 6 kilobases (kb) plasmid. On the other hand, when the bacteria were grown on agar medium (CFA-agar or Mueller-Hinton agar) two phenotypes of colonies could be observed: large colonies (LC) which were composed of non-adhesive bacteria and small colonies (SC) which were composed of a majority of adhesive bacteria; when the number of subcultures was not too great, a majority of colonies presented the small colonies phenotype. The plasmid content analysis showed the segregation of a high molecular weight plasmid DNA (approximately 100 kb) for the bacteria issued from large colonies phenotype.

Age Factors↗

Adhesion of enterotoxigenic Escherichia coli to the human colon carcinoma cell line Caco-2 in culture.

Enterotoxigenic Escherichia coli (ETEC) strains possessing colonization factor antigen I (CFA/I), CFA/II, CFA/III, and antigen 2230 were tested for their ability to adhere to the following cell lines: HeLa, HEp-2, HRT 18, Hutu 80, MDBK, MDCK, Vero, and Caco-2. ETEC strains adhered only to the Caco-2 cell line. Irrespective of the known adhesive factors, the ETEC strains that adhered to the brush border of human enterocytes also adhered to the Caco-2 cell line. The negative variants, which were cured of the plasmid encoding the adhesive factor, did not adhere. Adhesion of ETEC strains no longer occurred when the Caco-2 cells were pretreated with the homologous colonization factor antigen or when the bacterial cells were pretreated with homologous antibodies raised against the adhesive factors. This indicates that this adhesion is specific and that a different receptor exists for each type of adhesion factor. Electron micrographs of cross sections of the monolayer showed that the adhesion of ETEC strains to the brush border microvilli does not induce any lesion. Therefore, the Caco-2 cell line behaves in the same way as human enterocytes do.

Antigens, Bacterial↗

Adhesive properties of enteropathogenic Escherichia coli isolated from infants with acute diarrhea in Africa.

The adhesive properties of 69 enteropathogenic Escherichia coli (EPEC) strains were studied. The strains were isolated from diarrheal stools of infants in Burundi, Africa, and identified by serotyping with 12 classical EPEC O serogroup antisera. A test for adhesion to HEp-2 cells revealed that 52% of the strains showed localized adherence and 13% diffuse adherence. Localized adherence phenotype was found in previously described serogroups O86, O111, O125, O127, O128 and O142; strains belonging to another serogroup, O126, also exhibited localized adherence. Use of an EPEC adherence factor DNA probe in colony hybridization and in Southern blot techniques revealed that all strains exhibiting localized adherence and no strain exhibiting diffuse adherence produced a positive reaction; the genes were localized on high molecular weight plasmids (50-70 megadaltons). In vitro adhesion tests with human enterocytes performed concurrently with all 69 strains showed that only six of them adhered. These strains belonged to the O26, O117, O125, O128 and O142 serogroups. The adhesin CFA/I was detected only in the O128 Escherichia coli. The strain of serogroup O142 exhibited both adhesion to human enterocytes and localized adherence to HEp-2 cells, which suggests that the adhesive systems of enterotoxigenic and enteropathogenic Escherichia coli may coexist.

Bacterial Adhesion↗

[Inhibition by nifurzide of the adhesion capacity of enteropathogenic colibacillus to HEP-2 cells].

Enteropathogenic Escherichia coli (EPEC) adhere in vivo to enterocytes. This adhesion capacity can be obtained in vitro with Hep-2 cells on which a characteristic localized adherence (LA) is observed. We studied the effect of subinhibitory concentrations (SIC) of nifurzide, a nitrofurane derivative, on this bacterial adherence phenomenon. Three EPEC strains are used: 11201 (026 serogroup), 7958 (0128) and 7836 (0142). Various SIC (MIC/2; MIC/4;...; MIC/32) were added either to the culture medium of bacteria or to the Eagle medium in which bacteria and Hep-2 cells were mixed during the adhesion experiments. In each case an adhesion index is determined. Nifurzide strongly inhibits the adherence capacity of the three strains when concentrations ranging from MIC/2 to MIC/16 where added in both culture media. On the other hand three other nitrofurane derivatives which have no antibacterial effect did not inhibit adherence. The mechanism of the adherence inhibition by nifurzide is discussed.

Anti-Bacterial Agents↗

Characterization of Haemophilus influenzae isolated from patients with otitis media.

Two hundred and twenty-three Haemophilus influenzae strains isolated from patients with otitis media throughout France were characterized by biotype, serotype, antibiotic susceptibility, type of beta-lactamase production and human erythrocyte agglutination properties. All strains fell in one of two groups. One group consisted of encapsulated type b strains, 50% of which were biotype I, often resistant to ampicillin (38.5% of beta-lactamase producing strains) and seldom positive for haemagglutination (3.8%). The second group was composed of non-encapsulated strains, 42% of which were of biotype II, 10.6% beta-lactamase producers and 10.5% positive for haemagglutination.

Adolescent↗

Molecular biology of the HLA system in insulin-dependent diabetes mellitus.

Genetic studies indicate that the IDDM susceptibility genes in the HLA region are closely linked to the DR3 and DR4 specificities; however, these specificities do not define the actual susceptibility genes. Molecular studies confirm this hypothesis by demonstrating restriction fragment length polymorphism between DNA's of identical DR specificities and thereby separating the DR haplotypes into those strongly or weakly associated with IDDM. Further studies at the nucleotide sequence level demonstrate further heterogeneity, with DR4 being associated with at least three different DQ beta genes and five different genes of the DR beta-1 locus. However, the majority of these subtypes are now recognized either serologically or by T-cell responses in mixed lymphocyte cultures. Furthermore, the sequences associated with IDDM are those most commonly found in DR4 individuals, ie, Dw4 and DQw3.2. Clearly, these and other class II genes must be studied for additional DNA polymorphism and their relevance for IDDM. For example, the DX alpha, 2.1-kb Taql polymorphism shows a stronger correlation with IDDM than DR3. However, it is not even known if the DX alpha genes are expressed. In addition, little is known of the DQ beta and DR beta genes associated with different DR3-associated haplotypes. Furthermore, an IDDM susceptibility gene may contain important differences in flanking or intron sequences controlling expression of these genes. The methods of recombinant DNA technology are enabling these unanswered questions to be addressed.

Base Sequence↗

Multiplicity of serogroups and adhesins in enteropathogenic and enterotoxigenic Escherichia coli isolated from acute diarrhea in Senegal.

Escherichia coli strains were isolated from 228 children with diarrhea in Senegal from 1982 to 1984. Among these E. coli involved in cases of diarrhea, we found that 20.3% were enteropathogenic E. coli. Only 3.9% of the strains adhered to the brush borders of human intestinal enterocytes, and they belonged to different serotypes. All these adhesion-positive strains possessed genes encoding for the heat-stable enterotoxin, but their adhesive factors were different regarding serology with anti-colonization factor sera, hemagglutination patterns, electron microscopy structures, or major surface protein subunits.

Acute Disease↗

Tibial plateau fractures.

Certain factors in tibial plateau fractures that lead to increased disability may be avoided by following the objectives of articular surface restoration, good internal fixation, early knee motion, strengthening exercises, and soft-tissue repair. In some types of fractures, traumatic arthritis may be unavoidable.

Adult↗

Gestational diabetes mellitus is associated with HLA-DQ beta-chain DNA endonuclease fragments.

DNA from Caucasian normal healthy control subjects, non-gravid patients with insulin-dependent diabetes mellitus (IDDM) and gravida with gestational diabetes mellitus (GDM) were analyzed with DNA probes for HLA markers associated with HLA-DR and HLA-DQ to compare the hybridization patterns of their DNA after digestion with restriction endonucleases. We report HLA-DQ beta restriction endonuclease fragments to be presented with increased frequency in Caucasian gravida with GDM as well as in subjects with IDDM. These findings provide further evidence for genetic heterogeneity in GDM and are compatible with the presence of slowly evolving IDDM in some women with "carbohydrate intolerance of variable severity with onset or first recognition during pregnancy".

DNA↗

Characterization of three HLA-DR beta genes isolated from an HLA-DR 3/4 insulin-dependent diabetic patient.

Three HLA-DR beta genes were isolated from a Swedish HLA-DR3/4 insulin-dependent diabetes mellitus (IDDM) patient and characterized by restriction endonuclease mapping and nucleotide sequence analysis. Two out of the three DNA sequences differed from those of published DR beta-chain sequences. A DR beta-gene probe prepared from exon 4 and flanking sequences was used in a Southern blot analysis of blood donors' DNA and DNA from HLA-DR3/4 IDDM patients and HLA-DR-matched healthy control subjects. This probe differentiated HLA-DR3/4 IDDM patients and HLA-DR-matched controls in the Scandinavian population but not in the North American Caucasoid population.

Amino Acid Sequence↗

Zone approach to knee arthroscopy.

The zone approach to knee arthroscopy divides the knee into ten anatomic zones. This article presents the zone classifications and describes the combination of portals for the arthroscope, the probe, and the operating instruments. The particular leg position which is thought to allow the best visualization of each zone is also described. Alternate portals are necessary in certain situations, as in knees with tight ligamentous structures. This list of standard and alternate portals is not meant to be all-inclusive, but we do urge that all ten zones are examined during arthroscopy. The objectives of this article are to describe a method of arthroscopic examination that is both systematic and comprehensive, and to develop an arthroscopic nomenclature that allows easy localization and reporting of pathology in the knee joint.

Arthroscopy↗