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Biomedical subjects

G W Jones

Publications and source records attributed to G W Jones.

At least 91 records · Page 5Linked to original sources
PubMed1985

Susceptibility of Bos indicus and Bos taurus to Anaplasma marginale and Babesia bigemina infections.

The reaction of Bos taurus and pure-bred Bos indicus heifers to infection with the intraerythrocytic parasites Anaplasma marginale and Babesia bigemina was studied. B. bigemina infection at 18 months and A. marginale infection at 13 or 24 months resulted in slightly less severe reactions in pure-bred Bos indicus cattle than in Bos taurus. In both breeds, the reaction to A. marginale infection was more severe in older cattle. The severity of B. bigemina infection was not affected by a previous infection with A. marginale.

Age Factors↗
PubMed1985

The effect of citrate and polyamines on human benign prostate in organ culture.

A technique for short-term cultivation of slices of human benign prostate tissue in an organ culture environment is described. Minimum essential medium utilized was supplemented with 10 percent fetal bovine serum and 25 mg/mL of citrate, spermine, and spermidine. Spermine in the presence of testosterone in the culture medium induced morphological changes, enhancing the morphology of the tissue. The epithelium was well preserved morphologically. Citrate or spermidine together with testosterone does not enhance any morphological change. After seven days of culture, necrosis was developed. The spent culture medium showed a pattern of prostatic acid phosphatase production. When treated with spermine, the maximum level was reached at four days, after which it decreased. With spermidine or citrate, the maximum level is reached at two days of culture. Tissue β-glucuronidase activity was enhanced by either spermidine, spermine, or citrate together with testosterone. The biochemical studies suggested that explants of human benign prostate can be well maintained in organ culture for a few days.

Citrates↗
PubMed1983

Diagnosis and management of prostate cancer.

Representing 18% of male cancers, carcinoma of the prostate gland is the second most common cancer and the third leading cause of cancer deaths in US males. In 1982, it is estimated 73,000 new cases and 23,000 deaths will occur from the most common cancer in men older than 65 years of age. US blacks have the highest incidence in the world. Annual rectal digital examination of the prostate gland discovering a suspicious nodule or indurated area of the gland remains the earliest means of detection of the prostatic cancer in the asymptomatic man. However, more commonly the earliest unsuspected detection occurs in the surgical specimen removed following operations to relieve obstructive symptoms of benign prostatism. Survival of patients with this disease correlates with the stage and grade of disease at time of diagnosis, consequently it is imperative to ascertain the extent of disease in order to select the appropriate therapy for the patient. Radical prostatectomy, interstitial radiation implantation, and external radiation are the current means of treatment patients with low-stage disease, while hormonal manipulation alone or in combination with external radiation and chemotherapy are the primary means of treatment symptomatic patients with carcinoma of the prostate. The expected five-year survival for low-stage disease is 70-80%.

Aged↗
PubMed1983

Proteinaceous bacterial adhesins and their receptors.

The adhesion of bacteria to surfaces is an ecologically important property which enables them to colonize their natural habitats. Adhesion between bacteria mediated by sex pili and aggregation substances may also promote gene transfers. In this review, we describe the adhesive properties of bacteria (to eukaryotic and prokaryotic cells, and inert surfaces) and emphasize the characteristics of adhesins (structure, function, genetics, and morphology) and their cognate receptors on target surfaces. The physiochemical interactions between bacteria and surfaces can be described by the DLVO theory, but the interaction between bacterial adhesins and their receptor is better described as a ligand receptor interaction. The DLVO theory predicts that no physical contact can occur between bacteria and surface and, hence, predicts that adhesins must be filamentous in order to bridge the space between the two bodies and allow attachment of the bacteria. Adhesins are primarily proteinaceous, although adhesins of streptococci may involve dextrans or lipoteichoic acids. The cognate receptors for adhesins all appear to contain carbohydrates and as such as likely to be glycoconjugates with carbohydrate moieties acting as the receptor sites.

Adhesins, Escherichia coli↗
PubMed1982

Chemotaxis as a factor in interactions between HeLa cells and Salmonella typhimurium.

HeLa cells damaged by exposure to low pH released a diffusible attractant which greatly increased the collision frequency and hence the attachment of chemotactic Salmonella typhimurium. The attractant was tentatively identified as glycine. In contrast, when undamaged HeLa cells were used, no difference was found between a chemotactic parent strain and a non-chemotactic mutant in collision frequency or attachment. It is suggested that factors increasing cell membrane permeability could attract S. typhimurium to host cells in vivo.

Adhesiveness↗
PubMed1982

Adhesion of type A Pasteurella mulocida to rabbit pharyngeal cells and its possible role in rabbit respiratory tract infections.

Pasteurella multocida serotype A was found in association with the mucosal epithelium of the nasopharynges of rabbits with respiratory tract infections. The bacteria specifically attached to squamous epithelial cells of the pharyngeal mucosa both in vivo and in vitro and to some tissue culture cell lines such as HeLa. All strains with serotype A capsules were adhesive. With the exception of one serotype D strain, strains with capsular serotypes B, D, and E were at least 10-fold less adhesive. Bacterial adhesiveness was much reduced after pronase digestion, heat treatment, and homogenization, but removal of the hyaluronic acid capsule increased adhesion. Electron microscopy revealed that fimbriae were produced by an adhesive pasteurella strain, but not by two nonadherent strains. The attachment of the former strain to pharyngeal and HeLa cells was inhibited by N-acetyl-D-glucosamine. Together, these findings suggest that this amino sugar may be a component of the receptor on both animal cell surfaces and that the fimbriae may be the adhesions. It is proposed that bacterial attachment has a role in colonization and infection of rabbit upper respiratory mucosae.

Adhesiveness↗
PubMed1982

Association of adhesive, invasive, and virulent phenotypes of Salmonella typhimurium with autonomous 60-megadalton plasmids.

The plasmid DNA content of six invasive and adhesive strains of Salmonella typhimurium was determined, and all six strains (CR8500 [S850], CR6600 [TML], W118, NY, PR, and S2204) were found to harbor at least one plasmid equivalent in size to the 60-megadalton plasmid ("cryptic" plasmid), pSLT, which is normally resident in S. typhimurium strain LT2. The role of such 60-megadalton plasmids in the adhesive and invasive properties of strain CR6600, a commonly encountered salmonella pathogen that produces type 1 fimbriae, and strain CR8500, a representative FIRN biotype which does not produce type 1 fimbriae, was studied further by obtaining derivatives of these strains that no longer harbored an autonomous 60-megadalton plasmid. Strains CR6260 and CR6190 and strains CR8100 and CR8353, which were "cured" derivatives of strains CR6600 and CR8500, respectively, were significantly less adhesive and invasive in the HeLa cell test. A 53.5-megadalton colicin plasmid harbored by strain CR6600 did not detectably influence these properties. Additionally, strain CR6260 was avirulent, and strain CR8100 was 1,000 to 10,000-fold less virulent for orally infected mice as compared with their respective parental strains. Significantly, the virulence of strain CR8100 correlated with tissue colonization by bacteria that exhibited autonomous copies of a 60-megadalton plasmid. We propose that this plasmid exists in both autonomous and integrated states and that the in vivo environment selects for bacteria with autonomous plasmid copies which can express the virulent phenotype, thus enabling such strains to survive the defense mechanisms of the host.

Adhesiveness↗
PubMed1981

Blood hormone profiles in prostate cancer patients in high-risk and low-risk populations.

Epidemiologic data reveal that the incidence rate of prostate gland carcinoma among the black population in the United States (US) is several times higher than among Nigerians. A collaborative study between the two countries was undertaken, and blood hormone (testosterone [T], dihydrotestosterone [DHT], estrone [E1], estradiol [E2], and prolactin [P1]), total acid phosphatase (TP), and prostatic acid phosphatase (PAP) profiles in the two population groups were compared. In the US groups (patients and controls) there were significantly higher levels of T (P less than 0.01) and E1 (P less than 0.05) compared with the Nigerians. Also, the US patients had significantly higher levels of T (P less than 0.05) and E1 (P less than 0.01) compared with their matched controls. In the Nigerians T but not E1 levels were significantly lower (P less than 0.05) in patients compared with controls. DHT, E2, and P1 were not significantly different in patients and controls between and within the populations. Nigerian patients had higher levels (P less than 0.001) of TP and PAP compared with US patients. It is concluded that differences in blood hormone profiles in the two population groups are based on factors other than the genetic makeup of the populations.

Acid Phosphatase↗