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Biomedical subjects

R Heller

Publications and source records attributed to R Heller.

191 records · Page 11Linked to original sources
PubMedDate not supplied

The role of polymeric surface smoothness of biliary stents in bacterial adherence, biofilm deposition, and stent occlusion.

Bacterial adherence and biofilm deposition onto the surface of polymers used for biliary stents are the initial events that ultimately lead to stent occlusion. Vivathane is a new polymer with an ultrasmooth surface. In this study, stents made from Vivathane were compared to standard plastic stents in an in vitro model. Polyethylene, C-flex, and Vivathane stents were connected in parallel and perfused with infected bile. The surfaces of the polyethylene and C-flex stents developed exuberant bacterial growth and biliary sludge deposition. Vivathane stents were nearly free of bacteria and demonstrated no propensity for biliary sludge deposition. These results indicate that polymeric surface irregularities promote bacterial adherence, biofilm deposition, and accumulation of biliary sludge. The ultrasmooth surface of Vivathane does not allow bacterial adherence and biofilm deposition. Vivathane holds promise as a new polymer for use in biliary stents in long-term applications.

Bacterial Adhesion↗
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Electrically mediated drug delivery for treating subcutaneous and orthotopic pancreatic adenocarcinoma in a hamster model.

BACKGROUND: Current therapies for pancreatic adenocarcinoma only benefit a fraction of those diagnosed with this disease. New strategies for improving treatment are clearly needed. This study investigated the use of electrically mediated drug delivery for the treatment of pancreatic adenocarcinoma in a hamster model. MATERIALS AND METHODS: Hamster PC-1 pancreatic adenocarcinoma cells and Golden Syrian hamsters were used as a model. RESULTS: In vitro testing indicated that bleomycin was more effective than Cisplatin and Doxorubicin when delivered using pulsed electric fields. Treatment of subcutaneous tumors with bleomycin and electric fields resulted in a 100 percent complete response rate. No effect was observed when either drug or pulses were used alone. Treatment of tumors induced in the gland resulted in a 25 percent complete response rate. CONCLUSIONS: Electrochemotherapy was highly effective for subcutaneous tumors. There was also a significant antitumor effect for the more complex and clinically relevant intraoperative treatment of tumors in the pancreas.

Adenocarcinoma↗
PubMedDate not supplied

Lack of relationship between parity and level of carcinoembryonic antigen in women with breast cancer.

Women with high parity appear to be protected against the development of breast cancer. It has been suggested that those tumours which secrete carcinoembryonic antigen (CEA) are destroyed in women who develop cell-mediated immunity to embryonic antigen at the time of pregnancy or childbirth at an early age. A study of 335 patients with breast cancer was designed to test the hypothesis that circulating levels of CEA would be lower in women with high parity and an early age at first pregnancy or live birth. CEA levels were higher if measured in the presence of tumour metastasis. There was no association between CEA levels and parity, age at first live birth, age at diagnosis or cigarette smoking. Thus we have no evidence that breast cancers which express embryonic antigens, such as CEA, are preferentially destroyed by an immune response which has arisen from embryonic inoculation during or around an early childbirth.

Adult↗
PubMedDate not supplied

Identification of submicroscopic lymph node metastases in patients with malignant melanoma.

In order to detect micrometastatic disease, our laboratory has developed a method for evaluating lymph node sections from patients with stage 1 or 2 melanoma. Lymph nodes isolated from standard dissections are bivalved; one half is subjected to routine histopathological evaluation and the other half disrupted and placed into cell culture. The cultured cells are identified by cytologic examination, immunohistologic staining, and the presence of melanoma-associated antigens. Lymph nodes (448) from 62 patients with malignant melanoma were evaluated by tissue culture. Fifteen patients were upgraded from stage 1 or 2 to stage 3 disease after micrometastases were identified in lymph node cultures. Recurrence of disease in histologically node negative patients, during a mean 24-month follow-up, has only been observed thus far in patients with culture positive lymph nodes. In addition, these results add evidence to the belief that missed micrometastatic disease in regional nodes is a sign of occult systemic metastases that would account for the defined recurrence rate in histologically node negative patients.

Antigens, Neoplasm↗
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Families as "faculty": parents educating caregivers about family-centered care.

The Family Faculty program of The Children's Hospital of Philadelphia trains parents of children with special health care needs to present classes on family-centered care to physicians, nurses, and other hospital staff. Content of the classes weaves together the philosophy of family-centered care with individual family stories that relate the family's experience of illness as well as their care needs. Over the first year of its existence, the program educated over 900 employees in a 3,500-member workforce. Evaluation responses to the program have been uniformly positive. Educating caregivers about family-centered care through the stories and perspectives of parents enriches inservicing about communication and collaboration.

Caregivers↗
PubMedDate not supplied

[Bartonellosis: I. Bartonella henselae].

The recent discovery of the bacterium Bartonella henselae was mainly due to the development of molecular biology techniques adapted to microbial diagnosis and to the description of new human diseases linked to Aids. About 10% of pet cats and 33% of stray cats harbour that bacterium in their blood. In immunocompetent patients, that bacterium is responsible for human cat scratch disease, characterized essentially by a localized lymph nodes enlargement in the vicinity of the entry site of the bacteria. This disease occurs more likely in pet cats less than 1-year-old and infested with fleas. The bacterium is transmitted to humans by scratches or bites; the role of fleas is possible, but is not yet documented. In 5 to 13% of cases, the cat scratch disease appears as more severe, including health impairment, hepatitis, Parinaud's oculo-glandular syndrome, neurological complications or stellate retinitis. In immunocompromised patients, B. henselae is responsible for various clinical presentations: bacillary angiomatosis, bacillary peliosis, recurrent or persistent bacteremia or endocarditis. Diagnosis of infections due to B. henselae can be performed by serological specific testing with sensitivity and specificity values ranging from 75 to 100%. Cultivation of the bacterium is fastidious, particularly in cases of cat scratch disease. The most efficient diagnostic test is the in vitro DNA amplification which has the drawback to require a lymph node sample. Antibiotics are usually inefficient for the treatment of cat scratch disease. By contrast, in immunocompromised patients, these infections are successfully treated for a more or less long time by macrolides or tetracyclines or rifampin.

Animals↗
PubMedDate not supplied

[Bartonellosis. II. Other Bartonella responsible for human diseases].

In addition to Bartonella henselae, five other Bartonella species were involved in human pathology. As for B. henselae, ectoparasites seem to be responsible for the transmission of most or all these bacterial species. B. bacilliformis is responsible for Carrion's disease that occurs in some valleys of Colombia, Ecuador and Peru. This disease is transmitted by biting of infected sandflies. The bacterial reservoir is constituted by humans only. That disease occurs either as an acute form with severe infectious hemolytic anemia (or Oroya fever), or as benign cutaneous tumors, also called verruga peruana. Healthy blood carriers of the bacterium exist. Trench fever was described during the First World War. This non-lethal disease is constituted of recurrent febrile attacks associated particularly with osseous pains. The causative agent of the disease is B. quintana, transmitted by the body louse. Humans seem to be the reservoir of that bacterium. In some patients, B. quintana can be responsible for endocarditis, bacillary angiomatosis and chronic or recurrent bacteremia. Other human infections due to Bartonella sp. have been described: B. vinsonii, isolated from blood of small rodents, and B. elizabethae, the reservoir of which is currently unknown, can be responsible for endocardites. B. clarridgeiae (isolated from blood of 5% of pet cats and 17% of stray cats) may be responsible for human cat scratch disease. All these bartonelloses are diagnosed by non-standard blood culture or by in vitro DNA amplification or by serological testing. Their treatment requires tetracyclines or chloramphenicol or macrolides.

Animals↗