PubMed Health⌕ Search

Biomedical subjects

R Chan

Publications and source records attributed to R Chan.

At least 163 records · Page 9Linked to original sources
PubMed1981

Pasteurella multocida subdural empyema: a case report.

The first case of Pasteurella Multocida subdural empyema is reported. This was secondary to hematogenous spread from the pharynx to a chronic subdural hematoma. Positive cultures were obtained from the primary source, the blood and the subdural space. The patient was discharged with no neurological deficit following surgical drainage and parenteral antibiotics. The incidence, predisposing factors, clinical features, bacteriology, diagnostic procedures, treatment and mortality of subdural empyema are briefly discussed.

Brain Abscess↗
PubMed1981

Corynebacterium diphtheriae septicemia.

This report describes the case of a patient with chronic lymphocytic leukemia in whom septicemia caused by a nontoxigenic strain of Corynebacterium diphtheriae developed. Numerous abscesses were present in sections of liver and spleen taken at autopsy. The case is discussed, and the literature on infections caused by organisms of the genus Corynebacterium is briefly reviewed.

Diphtheria↗
PubMed1981

Citrate-tris(hydroxymethyl)aminomethane-mediated release of outer membrane sections from the cell envelope of a deep-rough (heptose-deficient lipopolysaccharide) strain of Escherichia coli O8.

A heptose-deficient lipopolysaccharide strain of Escherichia coli O8, strain F515, was found to release portions of its outer membrane when cells were exposed to 10 mM citrate buffer (pH 2.75) for 30 min and subsequently exposed to 100 mM tris(hydroxymethyl)aminomethane buffer (pH 8.00). The outer membrane component release was found to be composed of protein, lipopolysaccharide, phospholipid (cardiolipin, phosphatidylethanolamine, and phosphatidylglycerol), and alkaline phosphatase. The outer membrane component was released from the cell envelope in the absence of cell lysis, as no glucose-6-phosphate dehydrogenase activity or succinic dehydrogenase activity was detected. Morphologically, the outer membrane component appeared to consist of laminar fragments and vesicles which had an associated alkaline phosphatase activity.

Bacterial Proteins↗
PubMed1980

Radiotherapy (2500 rad) for testicular leukemia: local control and subsequent clinical events: a Southwest Oncology Group study.

The effectiveness of radiotherapy, 2500 rad over two weeks, in treating leukemic infiltrates of the testicles was studied in 38 boys who met the requirements for tissue conformation of testicular involvement and examination of the bone marrow. The study group was heterogeneous with respect to specific histology and prior therapy. Complete regression of testicular infiltrates was confirmed by repeated biopsy examinations of 32 of 33 patients undergoing the procedure. The single treatment failure occurred in a boy with acute myelogenous leukemia. In all other patients, local disease control following radiotherapy persisted throuthout the remainder of the clinical course. Three of 5 children, however, showed evidence of reseeding of the testicle as a part of the relapse process at post-mortem examination. Statistical analysis of data from the 35 patients with acute lymphocytic leukemia showed the subsequent course of the disease with respect to next relapse, involving either bone marrow (BM) or the central nervous system (CNS), to be dependent on the acute leukemia prognostic group, as determined by age and peripheral white blood cell count (WBC) at the time of diagnosis, and timing of extramedullary disease (EMD). Patients with poor prognosis at the time of diagnosis and EMD afterward had a 3.8 times greater risk of a subsequent BM or CNS relapse than did patients with good or average prognosis and no EMD at any time (P = 0.07). Of the candidate prognostic factors examined with repect to survival, only the number of prior BM relapses was of statistical significance (P = 0.044). Children with two or more prior BM relapses had the worst prognosis for survival from testicular relapse, with a death risk of 3.6 times greater per unit of time than that of children with no or one prior BM relapse. Protective BM and CNS rescue therapy was recommended for those otherwise in complete remission (CR) at the time of testicular relapse. The median times to next relapse for patients receiving both BM and CNS recue therapy and for patients given CNS recue only were 42+ and seven weeks, respectively ( P = 0.09). The type of rescue received did not appear to affect survival time following testicular CR.

Adolescent↗
PubMed1980

Distribution of types of Streptococcus pneumoniae isolated in Sydney in 1973--1974 and in 1979.

At The Prince of Wales Hospital, 357 pneumococci isolated in the laboratory from September, 1973, to May, 1974, and 268 pneumococci isolated from June to November, 1979, were serotyped. The pneumococci were isolated from patients and carriers in the hospital and in general practice. The type distribution resembled that described by Hansman regarding 1247 pneumococci isolated from 1965 to 1969. In each of the periods, the same seven predominant types--19, 23, 6, 3, 9, 11 and 15--were isolated in almost exactly the same order of frequency. Of the "epidemic" types--1, 2, 4, 5, 7 and 12--only type 12 was not isolated in the present study. This information may be of value in the choice of components for an appropriate polyvalent pneumococcal vaccine for susceptible children and adults in Australia.

Australia↗
PubMed1980

Production of mucoid microcolonies by Pseudomonas aeruginosa within infected lungs in cystic fibrosis.

Direct electron microscopic examination of postmortem lung material from cystic fibrosis patients infected with Pseudomonas aeruginosa has shown that these bacterial cells form distinct fiber-enclosed microcolonies in the infected alveoli. Similar examination of bronchoscopy material from infected cystic fibrosis patients showed that the fibres of the enveloping matrix are definitely associated with the bacterial cells. The fibers of the extracellular matrix stain with ruthenium red and are therefore presumed to be polyanionic. When mucoid strains of P. aeruginosa were recovered from cystic fibrosis patients and grown in a suitable liquid medium, they were found to produce large microcolonies whose component cells were embedded in a very extensive matrix of polyanionic fibers that could be stabilized by reaction with antibodies to prevent collapse during the dehydration steps of preparation for electron microscopy. When these mucoid strains of P. aeruginosa were used to produce pulmonary infections of rats by the agar bead method, the infected alveoli contained large fiber-enclosed bacterial microcolonies. We conclude that the cells of P. aeruginosa that infect cystic fibrosis patients form microcolonies that are enveloped in a fibrous anionic matrix and that these microcolonies can be duplicated in in vitro cultures and in animal model systems.

Cystic Fibrosis↗
PubMed1980

[Heterotopic homograft of the rat stomach: microsurgical technic].

More than by a practical viewpoint, the experimental graft of stomach is very useful like model for the study of gastrointestinal physiopathology. Starting from these considerations the AA. have set up a new method for the execution of stomach heterotopic homograft in rat and they have studied the secretory activity without immuno-suppressed therapy. Not inbred rats have been used; their middle survival has been of 9,3 days. The secretion has been regular up to 5th-6th day; in the same time the AA. have made histopathologic studies on the transplanted stomachs of animals that had been sacrificed at programmed intervals of time, which have outlined the progressive growth of a reaction of intense immunological rejection.

Animals↗
PubMed1980

[Orthotopic homograft of the rat stomach: microsurgical technic].

The principal aim of this study is to set up a new microsurgical technique that can be reproducible easily for the execution of orthotopic homograft of stomach in rat. The vascularization of homograft is given, for arterial district by a termino-terminal anastomosis between celiac artery of donor and right renal artery of receiving, and, for venous district, by a termino-lateral anastomosis between portal vein of donor and vena cava of receiving. The middle survival of rats that were had a graft, in this first stage of research, has been of 3 days, therefore it hasn't't been possible to look into the function of graft.

Animals↗
PubMed1980

[Assessment of the surgical risk by skin tests of cell-mediated reactivity and other methods].

In examining some procedures of general evaluation of the operative risk the Authors direct their attention to the performance of cell-mediate reactivity skin tests and consider a set of 42 patients (of whom 11 as controls, and 31 "high risk"). The results obtained are interesting and evidence the high reliability of these tests in evaluation of infective morbidity and mortality in neoplastic and non-neoplastic patients: in fact a negative response means high morbidity and mortality while a positive response corresponds to normal surgical healing. In tumoral patients, moreover a relationship between skin tests and clinical stage of the disease is observed: negativity of the test means a terminal stage and hence absolute inoperability: positivity corresponds to an advanced stage and hence relative operability (exploratory laparatomy and thoracotomy). The Authors conclude by stressing that the tests have a practical utility and prognostic value higher than those of other methods.

Adult↗
PubMed1980

[Mechanical sutures in digestive surgery. II. An experimental study of the cicatricial repair process].

The AA. intend to study the healing process of digestive sutures in dog that have been made with mechanical instruments that have metal agraphes. The used instruments are the American models of United Surgical Corporation in New York that have: --LDS pliers; --GIA pliers; --TA mod 90, 55, 30, pliers. They had made 15 operations of digestive surgery: gastric resections sec. Billroth II, anastomoses of ileum, colic anastomoses. In total they have made 45 sutures. After an established period the same animals were operated on again for controlling the results of made operations and the macro and microscopic evolution of sutures. The study of healing has shown a quick and exact repairing process for first intent, different from sutures that are made manually with threads that, notoriously, develop slowly for second intent.

Animals↗
PubMed1978

[Uses in vascular symptomatology of the ultrasonic flowmeter with Doppler effect in patients revascularized for peripheral obliterating arteritis].

The Authors present 38 cases of surgical revascularization for arteriosclerosis obliterans of the lower extremities, operated in Clinica Chirurgica of Ancona during the space of three Years, from 1974-1977. The morphological profile of the sphygmic wave and pressures of occlusion or Travis Winsor's index were studied pre and postoperatively with Doppler ultrasonic flowmeter. The patency of vascular grafts and after thromboendarterectomy was shown by T.W.'s index. With this method, besides establishing a program for postoperative arteriography, a lesser use of the latter was shown.

Arteriosclerosis Obliterans↗
PubMed1976

Prostaglandin synthetase activity from human rheumatoid synovial microsomes. Effect of 'aspirin-like' drug therapy.

Using a radiometric technique, prostaglandin synthetase activity was measured in vitro in the microsomal fraction of 19 synovial tissues taken from 17 rheumatoid arthritis patients. The enzyme was inhibited in vitro by low concentrations of several 'aspirin-like' drugs, though paracetamol and salicylic acid were virtually inactive. While the synthetase preparations from patients receiving indomethacin, ibuprofen, or naproxen therapy exhibited considerable activity in vitro, we were unable to show any activity in preparations from patients taking aspirin, even in low doses. These findings suggest that in vivo aspirin may be unique in being an irreversible inhibitor of the enzyme, compared with other 'aspirin-like' drugs.

Adult↗
PubMed1974

Superinfections of the lung. An evaluation by serial transtracheal aspirations.

A prospective evaluation of cephaloridine, cephalothin, and lincomycin was conducted in 85 patients with pneumonia. None of the 50 with previous history of allergic sensitivity to penicillin had an allergic reaction. All cases of pure "pneumococcal pneumonia" were cured, regardless of the drug. Eight patients with polymicrobial pneumonia were cured by the cephalosporins, while lincomycin was ineffective in four patients who had polymicrobial pneumonia. Although expectorated sputum and exudates from the nasopharyngeal and oropharyngeal areas contained large concentrations of Staphylococcus aureus and various Gram-negative bacillary species during and at the end of therapy, serial cultures of transtracheal aspirate and the clinical course failed to confirm "superinfection" of the lung.

Adult↗
PubMedDate not supplied

Intracranial hemorrhage in a neonate following prenatal cocaine exposure.

A term infant who had a positive urine drug screen for cocaine is reported. There was ultrasonographic evidence of an intracranial hemorrhage. A small area of low echogenicity in the left caudothalamic groove documented at 96 hours of age was resolved on repeat ultrasonography at 16 days of age. This neonate was born by repeat cesarean section and growth was appropriate for gestational age. The findings indicate the importance of considering cerebrovascular events in neonates exposed to cocaine in utero.

Brain↗
PubMedDate not supplied

The role of the microcolony mode of growth in the pathogenesis of Pseudomonas aeruginosa infections.

In nature Pseudomonas aeruginosa grows in two modes, the mobile "swarmer" cell and the glycocalyx-enclosed microcolony. The microcolony mode is numerically dominant perhaps because it provides adhesion in a favorable niche and protection from bacteriophages and phagocytic predators. When this organism colonizes the compromised human host, a broad spectrum of different types of infection is produced, ranging from asymptomatic persistent cystitis to the overwhelming bacteremia seen in neutropenic patients. These infections differ radically both in their degree of toxicity and invasiveness and in their susceptibility to control with specific antibodies and/or antibiotics. These differences may reflect the degree to which intact host defense mechanisms force the bacteria to adopt the defensive, microcolony mode of growth. As examples, the nearly intact host defense mechanisms and vigorous immune response of patients with cystic fibrosis force P. aeruginosa in pulmonary infections into a demonstrably cryptic, microcolony mode of growth that allows its persistence in the face of specific antibodies and antibiotics but limits its toxic activity and its dissemination. In contrast, the ruined defense mechanisms of burned skin allow the spread of bacteria in the mobile mode; toxic effects are seen in neighboring tissues, and a mixed mobile-microcolony reservoir population, whose mobile members can subsequently invade the circulatory system, is built up in the burned tissue. Thus, it is important to define the mode of bacterial growth in each type of P. aeruginosa infection and, where the microcolony mode is predominant, to understand the chemistry of the enveloping exopolysaccharide in order to limit its synthesis and/or facilitate its penetration by antibodies and antibiotics.

Animals↗