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PubMed1997

Brief heat shock treatment induces a long-lasting alteration in the glycolipid receptor binding specificity and growth rate of Haemophilus influenzae.

After brief heat shock treatment, clinical strains of nontypeable Haemophilus influenzae show a long-lasting change in the binding specificity for glycolipids and a markedly increased growth rate in vitro. Non-heat-shocked H. influenzae specifically binds to phosphatidylethanolamine (PE), gangliotetraosylceramide (Gg4), and gangliotriosylceramide (Gg3) and binds minimally to sulfatoxygalactosylceramide (SGC; also called sulfatide). After a 5-min heat shock at 42 degrees C, strains of H. influenzae showed a marked increase in binding to SGC and acquired the ability to bind to sulfatoxygalactosylglycerol (SGG) in thin-layer chromatography overlays. Additionally, heat-shocked H. influenzae cells showed an increased growth rate (twofold). Increased sulfatide binding and growth rate were retained for approximately 60 generations, after which the heat-shocked organisms reverted to their original glycolipid binding pattern (i.e., PE, Gg3, and Gg4) and growth rate. Such organisms could then be reexposed to heat, and the heat shock phenotype would be reestablished. After exposure of the organisms to brief heat shock, Western blotting of a surface extract of H. influenzae with anti-bovine-brain hsp-70 monoclonal antibody showed an increase in two protein bands at 82 and 60 kDa. This antibody was a potent inhibitor of the binding of heat-shocked H. influenzae to SGC and SGG but had no effect on PE, Gg3, or Gg4 binding in vitro. In contrast, an antibody against an H. influenzae PE-Gg3-Gg4-binding adhesin that was recently identified (J. Busse, E. Hartmann, and C. A. Lingwood, J. Infect. Dis. 175:77-83, 1996) selectively inhibited the organism's binding to PE and Gg3. This indicates that cell surface hsp-70-related heat shock proteins can mediate H. influenzae attachment to sulfoglycolipids following heat shock. We suggest that such increased binding to sulfated glycolipids may be a response to fever following H. influenzae infection in humans.

Antibodies, Blocking↗
PubMed1977

Formation of HfrH-type donor cells as a result of integrative suppression by R-F recombinant plasmids.

Three recombinant plasmids, resulting from recombination between an R plasmid of the FI incompatibility group and the F of HfrH, were introduced in a temperature-sensitive dnaA mutant to isolate Hfr-type-donors. All of the temperature-insensitive clones isolated from two of the three recombinant plasmids had the same origin and transfer pattern as the parental HfrH strain.

Chromosomes, Bacterial↗
PubMed1988

Molecular cloning of genes that specify virulence in Pseudomonas solanacearum.

The suicide plasmid pSUP2021 was used to introduce Tn5 into the Pseudomonas solanacearum wild-type strain K60. We isolated eight avirulent mutants after screening 6,000 kanamycin-resistant transconjugants by inoculating eggplant (Solanum melongena L. cv. Black Beauty) and tobacco (Nicotiana tabacum L. cv. Bottom Special) seedlings. The Tn5-containing EcoRI fragments from the eight mutants were unique, suggesting that numerous genes specify virulence in this species. These EcoRI fragments were cloned into pBR322 or pUC12, and one of the clones, pKD810, was transformed into K60. All of the kanamycin-resistant, ampicillin-sensitive transformants were avirulent. Three randomly selected avirulent transformants were shown to carry the Tn5-containing fragment in place of the wild-type fragment and to exhibit the same hybridization pattern as the original KD810 mutant did. With pKD810 as a probe, we identified cosmids carrying the wild-type virulence genes by using a genomic library of K60 prepared in pLAFR3. Two of the homologous cosmids, pL810A and pL810C, when introduced into KD810 by transformation, restored virulence and normal growth of this mutant in tobacco. Altogether, these data indicate that the gene(s) interrupted by Tn5 insertion in KD810 is essential for the virulence of P. solanacearum. Further characterization of this gene is now being completed by subcloning, transposon mutagenesis, and complementation analysis.

Cloning, Molecular↗
PubMed1999

Genetic diversity and mosaicism at the por locus of Neisseria gonorrhoeae.

The por genes of the predominant serovars of Neisseria gonorrhoeae circulating in a high-frequency transmitter core group located in Nairobi, Kenya, were examined for nucleotide sequence polymorphism. The level of por gene diversity did not differ significantly between core group-derived gonococcal strains and gonococcal strains originating elsewhere. However, por mosaicism appeared to be more frequent among core group-derived strains, suggesting that recombination of different por sequences may be a important strategy by which N. gonorrhoeae generates por gene diversity within core group populations. Despite extensive sequence variability, por expressed by gonococcal isolates of different geographic origin exhibited conserved patterns of nucleotide change, suggesting that diversity among por alleles may also be finite.

Base Sequence↗
PubMed1966

Effect of dark repair on ultraviolet sensitivity of bacteriophage-infected bacteria.

Feiner, R. R. (Columbia University, New York, N.Y.), and R. F. Hill. Effect of dark repair on ultraviolet sensitivity of bacteriophage-infected bacteria. J. Bacteriol. 91:1239-1247. 1966.-Changes in ultraviolet (UV) sensitivity of phage-host complexes during phage development have been studied for the following systems: T1 and Escherichia coli B, T1 and E. coli K-12S, lambda and E. coli K-12S. Complexes were formed with bacterial strains differing in ability to dark-repair UV damage to deoxyribonucleic acid and, after irradiation, were plated on bacteria differing similarly. In the first half of the latent period, the resistance of complexes formed with nonrepairing bacteria increased considerably; with T1 and E. coli B hcr(-), in 4 min the resistance became the same as that of complexes formed with repairing bacteria. The repair ability of plating bacteria affected survival curves only upon irradiation in the second half of the latent period after mature phages were present in the initial complex. Use of nonrepairing bacteria both for initial infection and for plating of late complexes resulted in a series of survival curves showing for all three systems the same pattern of change originally reported for T2-E. coli B complexes. Thus, a hitherto unexplained difference between radiation survival curves for T-even and T-odd phages seems due to repair of T-odd phages by the host.

Coliphages↗
PubMed1983

Fusion of the Saccharomyces cerevisiae leu2 gene to an Escherichia coli beta-galactosidase gene.

The promoter and translation initiation region of the Saccharomyces cerevisiae leu2 gene was fused to the Escherichia coli beta-galactosidase gene. This fusion located the control region of the leu gene and orientated its direction of expression. When the fusion was placed into yeast cells, beta-galactosidase was expressed under the same regulatory pattern as the original leu2 gene product: its synthesis was repressed in the presence of leucine and threonine. Sensitive chromogenic substrates for beta-galactosidase were used to detect expression in isolated colonies growing on agar medium. Mutant yeast cells with increased beta-galactosidase activity were identified by the color of the colonies they formed. One class of mutants obtained appeared to affect ars1 plasmid maintenance, and another class appeared to affect beta-galactoside uptake.

3-Isopropylmalate Dehydrogenase↗
PubMed1995

Genome size, fluorochrome banding, and karyotype evolution in some Hypochoeris species.

Four South American and two European species of Hypochoeris (Asteraceae) were studied using fluorochrome banding, and genome size was determined by flow cytometry, in order to obtain information about microevolution in this genus and about its primary origin. Fluorochrome banding patterns showed GC-rich repeated sequences, particularly around the nucleolar organizer regions. Few differences appeared among the South American species. Nevertheless, determination of nuclear DNA content and base composition revealed significant differences among these species. The phylogenetic position of Hypochoeris robertia, which has the smallest DNA content, is discussed with regard to chromosome evolution in this genus.

Biological Evolution↗
PubMed2004

Primary vertebral osteosarcoma: imaging findings.

PURPOSE: To evaluate patient age and sex and location and imaging appearances of primary vertebral osteosarcoma (PVOS) compared with histologic subtypes. MATERIALS AND METHODS: Retrospective review (1915-2001) of imaging findings in patients with histologically proved primary osteosarcoma of vertebral column was performed. Two radiologists in consensus reviewed findings for location, origin site, matrix pattern, and spinal canal invasion and compared them with histologic subtypes. Radiation-induced, Paget, metastatic, and multifocal osteosarcoma were excluded. RESULTS: Of 4,887 osteosarcoma cases, 198 (4%) were PVOS arising from vertebral column. There were 103 female and 95 male patients (age range, 8-80 years; median age, 34.5 years). Involvement included cervical (27 patients), thoracic (66 patients), lumbar (64 patients), and sacral (41 patients) spine. Adequate imaging findings were available in 69 patients, and involvement of two levels was seen in 12 (17%). In nonsacral spine, most tumors (44 cases) arose from posterior elements, with partial involvement of vertebral body. Lesions confined to vertebral body were less frequent (12 cases). Sacral tumors involved body and sacral ala. The most common histologic subtypes were osteoblastic (47 patients), chondroblastic (12 patients), telangiectatic (four patients), fibroblastic (four patients), small cell (one patient), and epithelioid (one patient). The majority (55 cases) demonstrated osteoid matrix mineralization; 17 showed marked mineralization. Five cases with marked mineralization were confined to vertebral body, with "ivory vertebra" appearance. Purely lytic pattern was seen in 14 (20%) cases. Lytic pattern was seen in four (100%) telangiectatic, three (75%) fibroblastic, three (25%) chondroblastic, three (6%) conventional osteoblastic, and one (100%) small-cell subtypes. Invasion of spinal canal was common (84% of cases). Appearance simulating osteoblastoma without soft-tissue mass was present (seven cases). Pathologic compression fractures were identified (seven patients). CONCLUSION: This study provides age and sex distribution and location and imaging features in a large series of PVOS.

Adolescent↗
PubMed1997

Gastrointestinal submucosal tumors: evaluation with endoscopic US.

PURPOSE: To describe the endoscopic ultrasound (US) features of benign versus malignant submucosal tumors throughout the gastrointestinal tract. MATERIALS AND METHODS: One hundred nine patients aged 24-81 years suspected to have submucosal tumors (11 esophageal, 41 stomach, 24 duodenal, and 33 colorectal tumors) at barium studies or endoscopy underwent endoscopic US. The layer of origin, internal echo pattern, and lesion margin were analyzed by means of consensus and independent interpretation by three radiologists. RESULTS: Endoscopic US findings revealed several distinct patterns among various submucosal tumors. Sixteen (94%) of the 17 homogeneous lesions with histopathologic findings of malignancy were hypoechoic, although 29 (43%) of the 68 homogeneous lesions with histopathologic findings of benignity were similarly hypoechoic. Homogeneous lesions that were anechoic, of intermediate echogenicity, or hyperechoic were almost exclusively benign (39 [98%] of 40). In contrast, 23 (96%) of the 24 malignant lesions were heterogeneous (n = 7) or homogeneously hypoechoic (n = 16). The sizes of benign and malignant lesions were significantly different (P < .05). There was no significant difference in the echo pattern (i.e., homogeneous versus heterogeneous), but there was a significant difference in the proportion of hypoechoic versus nonhypoechoic lesions (anechoic, hyperechoic, or of intermediate echogenicity; P < .001). CONCLUSION: The differential diagnosis of gastrointestinal submucosal tumors is assisted with endoscopic US.

Diagnosis, Differential↗
PubMed1984

Comparison of lactate and glucose metabolism in the developing porcine placenta.

The present experiment was conducted to determine whether lactate is an important metabolic substrate for the developing porcine placenta. Pregnant gilts were anesthetized with pentobarbital sodium (5 mg/kg) at 65, 85, or 110 days of gestation and underwent an abdominohysterectomy. Fetal and maternal placental tissues were obtained and isolated for enzyme analysis and tissue incubations. Tissues were incubated for 2 h in Krebs-Ringer bicarbonate buffer containing 10 mM glucose, 1.0 mM Na-palmitate, 2.0 mM L-lactate, and 2% albumin. The incorporation of glucose or lactate into CO2, total lipids, and fatty acids was examined by radioactive tracers. Lactate was shown to be at least as important a substrate as glucose for utilization through these metabolic pathways in both the fetal and maternal placentas during gestation. This ability to metabolize lactate may serve as a conservation mechanism to spare other nutrients for transfer to the fetus. Additionally, analysis of enzyme and incubation data indicated that the fetal and maternal placenta follow different developmental patterns, implying the origins for (or mechanisms of) regulation of these two tissues may differ.

Animals↗
PubMedDate not supplied

Friedrich Theodor von Frerichs (1819-1885) and Bright's disease.

BACKGROUND: Richard Bright (1789-1858) discovered that edema and proteinuria are linked with renal disease. Friedrich Theodor von Frerichs (1819-1885) performed microscopic studies on Bright's disease and wrote the first German textbook of nephrology. The present contribution analyzes Frerichs' work. METHODS: Frerichs' career and his book Die Bright'sche Nierenkrankheit und deren Behandlung are examined in terms of contemporary medical knowledge. RESULTS: Frerichs conducted clinical and microscopic studies that led him to conclude that Bright's disease is a single pathological entity with many possible causes. Frerichs identified three stages through which the condition progresses. Although an oversimplification, Frerichs' various stages are reflected in the current notion that chronic renal disease, irrespectively of its etiology, relentlessly progresses to end-stage renal failure with common features of tubulointerstitial fibrosis and tubular atrophy. After writing his monograph, Frerichs never touched on renal disease again and is actually better known for his contributions to hepatology. Frerichs was a volatile and difficult person who was not always fair to his students and colleagues. CONCLUSION: Frerichs put the study of renal diseases on the map in Germany and made the novel observation that chronic renal diseases follow similar morphological patterns despite multiple origins.

Germany↗
PubMed1975

Projections of the trapezoid body and the superior olivary complex of the Kangaroo rat (Dipodomys merriami).

Glass micropipettes filled with 2 M sodium cyanide were used to physiologically locate and iontophoretically damage the nucleus of the trapezoid body (NTB), the medial superior olive (MSO), and the lateral superior olive (LSO). Mechanical lesions were made in the trapezoid body as it leaves the cochlear nuclei. After a 3- to 10-day survival time the projections and terminal degeneration were traced with the Fink-Heimer and Nauta-Gygax stains. The ventral cochlear nucleus (VCN) projects via the trapezoid body to ipsilateral LSO, ipsilateral preolivary nuclei, ipsilateral lateral and a contralateral medial dendritic fields of MSO, and contralateral NTB; there is also a small ipsilateral projection to the ventral nucleus of the lateral lemniscus (VNLL) and the central nucleus of the inferior colliculus (CNIC). Some trapezoid body fibers ascend via the contralateral lateral lemniscus to VNLL, DNLL (dorsal nucleus of the lateral lemniscus), and CNIC. There is no projection from the ventral cochlear nucleus to the ipsilateral NTB and contralateral preolivary nuclei. All portions of NTB project ipsilaterally to LSO (ventral NTB to dorsomedial LSO, dorsal NTB to ventral LSO) and to the retro-olivary nucleus. In two animals with NTB lesions there is also degeneration in the ventromedial portion of the ipsilateral facial nucleus. NTB projects contralaterally by way of the stria of Monakow to the pyramidal and molecular cell layers of the dorsal cochlear nucleus (DCN). The NTB does not project ipsilaterally to MSO, preolivary nuclei, VNLL, DNLL and CNIC. Contralaterally there are no projections to any of the nuclei of the auditory pathway except the DCN. Most MSO projections are ipsilateral. The densest goes by way of the lateral lemniscus to the lateral aspect of the ipsilateral CNIC, terminating throughout its dorsoventral axis. MSO also projects bilaterally to the pyramidal and molecular cell layers of dorsal cochlear nucleus (DCN), and ipsilaterally to the ventral portion of the motor nucleus of V and to the facial nucleus. MSO does not project ipsilaterally to the LSO, NTB, preolivary, VCN and retro-olivary nuclei. On the contralateral side, all structures except the DCN are free of projection patterns from axons originating in the MSO. LSO projects bilaterally to the central and ventral portions of CNIC and to the nuclei of the lateral lemnisci, and ipsilaterally to the large and small spherical cell areas of anterior ventral cochlear nucleus (AVCN) and to all portions of DCN. The LSO does not project ipsilaterally to the NTB, MSO, preolivary and retro-olivary nuclei. On the side opposite, this nucleus does not project to NTB, MSO, retro-olive, VCN, preolivary and LSO. For all lesions regardless of the site, there is no degeneration found rostral to the CNIC. The medial geniculate body or other structures in the diencephalon or cortex are free of any fields of terminal degeneration.

Animals↗
PubMed1986

Objective evaluation of fibrosis in human testicular biopsies by analysis based on optical diffractometry.

Bilateral testicular biopsies were obtained from 27 patients and submitted to two different treatments for each of them: firstly, a classical fixation and colouring, permitting the histopathological diagnosis and subjective appreciation of the degree of fibrosis; secondly, a new objective technique based on optical diffractometry: this method is based on the analysis of light intensity distribution in the diffraction pattern of an original image. Using two different methods of discriminant analysis, we observed some errors due to the subjective examination; in particular, several fibrosed samples had been judged as 'normal' by the histopathologist. Moreover, we showed the existence of some heterogeneity between different slides from the same original biopsy.

Biopsy↗
PubMed1978

[Kaposi sarcoma. A short review on a rare disease].

Pathological, clinical, epidemiological and immunological aspects of a rare tumor, Kaposi's sarcoma, are briefly discussed. The prevalence of the disease in an African population raises questions about genetic and environmental factors in its carcinogenesis. Immunological data indicate a probable viral origin. The clinical patterns seem to be influenced by alterations of the immune defense mechanisms. Most questions about its biological behaviour remain to be answered yet.

Adolescent↗
PubMed1992

LSA: a new liver-specific antigen in the rat. I. Purification and characterization.

A liver-specific antigen (LSA) was purified to homogeneity from rat liver by conventional methods of protein chemistry. By consecutive 100,000 g centrifugation, ammonium sulfate precipitation, ion-exchange chromatography on DEAE-cellulose, gel filtration on Sephadex G-200, ion-exchange chromatography on CM-cellulose and affinity chromatography on concanavalin-Sepharose, it has been possible to isolate a preparation that migrated as a single band on SDS-PAGE. This preparation gave a complete identity pattern with the original crude rat liver extract when tested by double immunodiffusion. This antigen has a molecular weight of 72.5 kD with an electrophoretic mobility in the region of alpha 2-globulins. The LSA proved to be thermolabile since exposure to 55 degrees C completely destroyed the antigen. Exposure of the LSA to different pH ranging from 4 to 10 had no detrimental effect on its antigenic activity. The amino acid composition of the LSA revealed that the acidic amino acids out-number the basic amino acids, with glutamic acid being the most abundant of them. Failure of beta-mercaptoethanol to split the LSA molecule suggests the absence of sulfhydryl groups related to its antigenic activity. Subcellular fractionation of rat liver revealed most of the antigenic activity in the 100,000 g supernate, i.e. the soluble cytoplasmic fraction of the liver (cytosol). By contrast, the LSA was absent from isolated Kupffer cells from rat liver. The absence of any carbohydrate or lipid from the purified preparation of this antigen, in conjunction with the destructive effects of trypsin suggest that the LSA is a protein or a moiety closely associated with proteins.

Amino Acids↗
PubMed1993

Development of the pharyngeal arch system related to the pulmonary and bronchial vessels in the avian embryo. With a concept on systemic-pulmonary collateral artery formation.

BACKGROUND: The literature is ambiguous as to the question of the developmental background of systemic-pulmonary collateral arteries. These are found in combination with various congenital heart malformations such as pulmonary atresia. From a clinical point of view, it is of interest to know whether we are dealing with the persistence of transient embryological vessels such as ventral segmental arteries or parts of pharyngeal arch arteries or with the prenatal or postnatal recruitment of the bronchial vasculature that normally supplies the lung. This study of the embryology of the extrapulmonary and intrapulmonary vasculature aims at a better understanding of the variations in origin, course, branching pattern, and histology of collateral arteries. METHODS AND RESULTS: Serial sections of quail embryos ranging between stage HH11 and stage HH28 were incubated with a monoclonal antibody (alpha MB1) against endothelial cells and their precursors. Additional series of chick embryos were injected with india ink to study the lumenized vascular patterns. A splanchnic plexus consisting of endothelial cells and precursors is present around the foregut before the lung buds develop. This plexus expands and gives rise to the pharyngeal arch arteries, the ventral pharyngeal veins, the pulmonary vessels, and the bronchial vessels, including the intrapulmonary vessel network. During two subsequent periods, the splanchnic plexus is transiently connected to the systemic arteries and veins. The bronchial arteries and veins develop in the second period from these transient vessels. The expansion and extension of the splanchnic plexus to many organs during the formation of the bronchial vessels explains the varying course and branching pattern of the bronchial vasculature. CONCLUSIONS: These results show that we are not dealing with two or more individual vascular systems that contribute to the developing vessels of the lungs but with one vascular plexus that normally gives rise to the pulmonary and bronchial vasculature but has the potential to give rise to other systemic-pulmonary connections.

Animals↗
PubMedDate not supplied

Risk of basal and squamous cell carcinomas of the skin in Sion, Switzerland: a case-control study.

AIMS AND BACKGROUND: Non-melanocytic skin cancers are the most common cancers in white populations. Studies on populations of Anglo-Saxon and Mediterranean origins highlighted different patterns of risk of basal-cell carcinoma and squamous-cell carcinoma in relation to sunlight exposure, skin characteristics and phenotype susceptibility. In Sion, and in Switzerland as a whole, the high incidence suggests the possible presence of additional risk factors or of a different pattern of exposure to solar radiation as well as different composition of pigmentary traits and skin sensitivity to sun. METHODS AND STUDY DESIGN: We conducted a case-control study of 146 cases (73% of eligible cases) and 144 controls (81% of eligible subjects) to further evaluate the relationship between nonmelanocytic skin cancer and risk factors in the Sion population. Interviews were conducted by trained interviewers with a standardized questionnaire. RESULTS: Pigmentary characteristics such as blonde and red hair as well as tendency to sunburn without tanning and number of sunburns showed a statistically significant and independent risk increase in basal-cell carcinoma. Sun exposure during recreational activities (outdoor sports) showed a risk increase in basal-cell carcinoma with borderline statistical significance. Analysis of squamous-cell carcinoma risk was limited by the small number of cases, but it was positively associated with lifetime exposure to sun during outdoor work and with skin characteristics. CONCLUSIONS: Results confirmed previous suggestions of a different mechanism leading to malignant transformation of target cells from the basal and squamous epidermal layers, mediated by different phenotypes, and conditioning the ability to develop an effectively protective tan.

Adult↗