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Biomedical subjects

C Busch

Publications and source records attributed to C Busch.

At least 127 records · Page 7Linked to original sources
PubMed1993

Staging of bladder carcinoma by computer tomography-guided transmural core biopsy.

In an attempt to improve staging of bladder cancer, computed tomography-guided transmural core biopsy was performed in 17 patients. In the first four patients a 0.9 mm cutting needle was used. This small needle yielded easily fragmented cores and consequently the remaining biopsies were taken with a 1.2 mm needle with an improved result. In all but one case sufficient histological material to allow a diagnosis was obtained by the core biopsy technique. Transmural tumor infiltration, as verified in corresponding cystectomy specimens, could be identified more often with the core biopsy than in biopsies obtained by transurethral resection. False negative diagnosis occurred when the tumor was not clearly visible on the computed tomography scan. No short-term side effects of clinical importance were found with the procedure.

Adenocarcinoma↗
PubMed1993

In vivo prostanoid formation during acute renal allograft rejection.

Vasoconstriction during acute renal allograft rejection may be regulated by increased formation of vasoactive prostanoids. To address this hypothesis we investigated the biosynthesis of thromboxane (Tx)A2, a potent vasoconstrictor and platelet agonist, of prostacyclin (PGI2), a vasodilator and platelet antagonist, and of prostaglandin (PG)E2, a mediator of salt and water excretion, in nine children with 12 acute rejection episodes, prospectively during the first 7 weeks after renal transplantation. We used physicochemical analysis of stable urinary prostanoid index metabolites. Rejection crises were associated with an increase in TxB2 excretion from baseline median 9.2 (range 1.9-18.6) ng/h/1.73 m2 to 21.2 (range 10.0-133.0) ng/h/1.73 m2 (P < 0.005) during acute rejection episodes. Methylprednisolone pulse therapy resulted in a partial reduction, but not normalization of TxB2 excretion. Urinary 2,3-dinor-TxB2 was slightly stimulated during allograft rejection, urinary 11-dehydro-TxB2 did not change significantly. Renal PGI2 and PGE2 biosynthesis remained essentially unchanged. In contrast to acute graft rejection, patients with chronic graft rejection and those with stable graft function on different immunosuppressive regimens with or without cyclosporin A did not present stimulated renal TxA2 formation. Increased renal TxA2 formation in acute renal allograft rejection is likely to mediate vasoconstriction and potentiate the loss of renal blood flow and glomerular filtration rate, in the absence of an adequate response of the renoprotective prostanoids PGI2 and PGE2.

Acute Disease↗
PubMed1992

Characterization of a plasma retinol-binding protein membrane receptor expressed in the retinal pigment epithelium.

A specific membrane receptor for plasma retinol-binding protein (RBP) is expressed in the retinal pigment epithelium (RPE). When chemically cross-linking RBP to RPE membranes, an 86-kDa RBP.RBP receptor complex is formed, and a 63-kDa protein was identified as the RBP-binding membrane protein (Båvik, C.-O., Eriksson, U., Allen, R., and Peterson, P. (1991) J. Biol. Chem. 266, 14978-14985). To explore in more detail the characteristics of this membrane receptor, we have generated a monoclonal antibody, A52, to the 63-kDa protein (p63). A52 binds the 86-kDa RBP.RBP receptor complex and p63. Several lines of evidence suggest that p63 is not a regular integral membrane protein, and it occurs in different forms. One form is firmly attached to membranes, is part of a high molecular weight complex, and is able to bind RBP. The other form of p63 can be removed from membranes by treatment with an alkaline buffer and is unable to bind RBP. Both forms of p63 contain extensive hydrophobic domains and are found in the detergent phase upon extraction with Triton X-114. The expression of p63 is restricted to RPE, and immunohistochemical localization of tissue sections from bovine retina showed highest expression in the basolateral portion of RPE cells. Immunofluorescence localization, using isolated RPE cells, showed that p63 is exposed on the cell surface of newly isolated RPE cells.

Animals↗
PubMed1992

[Scapulectomy as an extremity preserving intervention in surgery of soft tissue sarcoma].

In the treatment of soft tissue sarcomas, radical surgery may mean total scapulectomy. If the tumour is localized next to the scapula wide margins can be better achieved by an operation of this kind than by resection of soft parts. In the planning of these operations radical surgery has priority. The functional results after total scapulectomy is acceptable. There is a distinct reduction of shoulder mobility, especially in abduction. As the peripheral joints are fully conserved, the extremity can be used very well in daily life. The indications for total scapulectomy and the technique are discussed with reference to two clinical cases.

Follow-Up Studies↗
PubMed1992

Expression of cellular retinoid-binding proteins during normal and abnormal epidermal differentiation.

Retinoids have important roles in growth and differentiation of epidermal cells. We have analyzed the expression of two intracellular retinoid-binding proteins, the cellular retinol-binding protein type I and the cellular retinoic acid-binding protein type I, during normal and abnormal epidermal differentiation. Both proteins were found to be expressed in normal epidermis with increasing expression from basal layer towards superficial layers. In psoriatic lesions, a hyperproliferative condition of the skin, the epidermal expression of cellular retinol-binding protein I was induced, whereas expression of cellular retinoic acid-binding protein I was sharply down-regulated. This and other features of psoriatic lesions indicate that down-regulation of cellular retinoic acid-binding protein I expression might cause aberrant retinoid-regulated gene expression in skin. In basal and squamous cell carcinomas, cellular retinoic acid-binding protein I expression was down-regulated, whereas cellular retinol-binding protein I was expressed. Apart from epidermal cells, a mesenchymal, dendritic cell-type, strongly expressing cellular retinoic acid-binding protein I, was identified in the dermis. In several hyperproliferative conditions of the skin, including psoriasis, and squamous and basal cell carcinomas, this cell type was abundant. These results have implications for the role of retinoids in normal and abnormal epidermal differentiation and suggest that part of the phenotype of psoriasis is due to inappropriate metabolism of retinoic acid in skin.

Adult↗
PubMed1992

Reference intervals and developmental changes in urinary prostanoid excretion in healthy newborns, infants and children.

Urinary excretion of prostaglandins E2, F2 alpha, E-M (7 alpha-hydroxy-5, 11-diketotetranor-prosta-1, 16-dioic acid), 6-keto F1 alpha, 2,3-dinor-6-keto-F1 alpha, thromboxane B2, 2,3-dinor-thromboxane B2 and 11-dehydrothromboxane B2 was determined by gas chromatography-mass spectrometry in 83 healthy subjects aged one day to 37 years. The excretion rates of all prostanoids increased with advancing age. After correction for 1.73 m2 body surface area, only urinary excretion rates of prostaglandins E-M and 6-keto-prostaglandin F1 alpha depended on age. Reference intervals were calculated as the 10th and 90th percentiles for prostaglandins E2 (4-27 ng/h/1.73 m2), F2 alpha (23-87 ng/h/1.73 m2), 2,3-dinor-6-keto-F1 alpha (4-19 ng/h/1.73 m2), thromboxane B2 (1-21 ng/h/1.73 m2), 2,3-dinor-thromboxane B2 (8-36 ng/h/1.73 m2) and 11-dehydro-thromboxane B2 (15-87 ng/h/1.73 m2) in all subjects, and for prostaglandins E-M and 6-keto-prostaglandin F1 alpha in subjects aged 30 days or less (110-1140 ng/h/1.73 m2 and 7-23 ng/h/1.73 m2) and older than 30 days (62-482 ng/h/1.73 m2 and 2-12 ng/h/1.73 m2). High urinary excretion of prostaglandins E-M and 6-keto-F1 alpha during the newborn period and some distinct changes in urinary excretion of prostaglandin E2 and thromboxane B2 with advancing age suggest that these prostanoids might play a specific role during child development.

6-Ketoprostaglandin F1 alpha↗
PubMed1992

Expression of proliferative cell nuclear antigen (PCNA) in urinary bladder carcinoma. Evaluation of antigen retrieval methods.

Proliferative cell nuclear antigen (PCNA) expression was analyzed in formalin-fixed and paraffin-embedded specimens from patients with urinary bladder cancer using three different anti-PCNA monoclonal antibodies. In 20 recent cases a positive correlation was found between the extent and intensity of PCNA staining and grade of malignancy. In 95 specimens, three to six years old, extensive positive staining was detected in 15 and 23% of grade 2B and 3-4 tumors, respectively. No equivalent staining was found in the grade 1 and 2A tumors. In material more than six years old, a remarkably weak staining was observed regardless of grade. Similarly, in a test of archival material of tonsils a very weak immuno-reactivity was found as compared with fresh material. However, antigen retrieval by microwave heating of the tissue sections was possible in the majority of all cases, and the difference in extent and intensity of the staining between low and high grade tumors remained.

Antibodies, Monoclonal↗
PubMed1992

Urethral reconstruction with a new synthetic absorbable device. An experimental study.

Four centimeters of the canine urethra was replaced by a graft consisting of a polyglactin fiber mesh tube, coated with polyhydroxybutyric acid. Microscopic examination 8-12 months later showed almost complete regeneration of the urethral epithelium and the adjacent connective tissue. The neo-urethra was patent and there were no anastomotic strictures, nor was there any inflammatory reaction around the urethra. The validity of this concept in humans remains to be proved.

Animals↗
PubMed1992

Safety aspects and diagnostic findings of serial renal allograft biopsies, obtained by an automatic technique with a midsize needle.

Percutaneous biopsy is an important diagnostic procedure in evaluating the renal allograft with compromised function. Graft losses and haemorrhagic complication are major risks. To minimize these problems we used a midsize TruCut needle, controlled by an automatic firing device (Biopty-Cut), fixed to an ultrasound guidance system. Core biopsies of 1.2 x 20 mm were obtained from 1,421 kidney grafts. On 5 occasions a haemorrhagic complication that required prolonged hospitalization or intervention occurred. No grafts were lost as a consequence of the biopsy procedure. Typical histological morphological parameters found during allograft rejection has earlier been established. Using a protocol with 27 histological parameters this study confirms that recognized criteria for rejection can be relied upon even with this smaller needle. The results showed that the degree of oedema and lymphocytic infiltration of the interstitium and in the arterial wall discriminated best between rejecting grafts and non-rejection grafts.

Adult↗
PubMed1992

A new biodegradable patch for closure of atrial septal defect. An experimental study.

Biodegradable patches made from polyhydroxybutyrate (PHB) were used to close experimentally induced atrial septal defect in six calves. The implants were evaluated after 3-12 months macroscopically and by light and scanning electron microscopy with regard to regeneration of tissue and degradation of the polymer. At implant degradation, complete endothelial layers facing the right and left atrium were observed, with a subendothelial layer of collagen and some smooth-muscle cells. The patch was degraded by polynucleated macrophages, and 12 months postoperatively no polymer material was identifiable at ordinary light microscopy, but in polarized light small particles of polymer with persisting foreign body reaction were still seen. Scanning electron microscopy revealed a complete layer of surface cells with morphologic signs of endothelium. There was no shunt or sign of infection. Biodegradable PHB patches implanted in atrial septal defects in this experimental model thus prompted formation of regenerated tissue that macroscopically and microscopically resembled native atrial septal wall. The total degradation time exceeded 12 months.

Animals↗
PubMed1992

Regeneration of pericardial tissue on absorbable polymer patches implanted into the pericardial sac. An immunohistochemical, ultrastructural and biochemical study in the sheep.

A new absorbable polymer prepared from polyhydroxybutyrate (PHB) was inserted as a pericardial patch in sheep to serve as a temporary scaffold for regeneration of pericardial tissue. Postoperative adhesions were rare or absent. The present study focuses on characterization of the regenerated surface cells. The luminal surface of the regenerated tissue was covered with a complete layer of mesothelium-like cells which at light and scanning electron microscopy resembled those in native pericardium. Immunohistochemical stainings for cytokeratin and thrombomodulin were positive in these cells. Heparan sulfate proteoglycan was found in a basement-membrane-like structure beneath the surface cells, as in the normal pericardium. Transmission electron microscopy of the regenerated surface revealed cells with the characteristics of mesothelium. Prostacyclin production in the regenerated tissue was similar to that in native pericardium. The results indicate regeneration of a mesothelial layer with many of the important functions of native mesothelial cells. This may explain the presently and previously observed prevention of pericardial adhesions after cardiac surgery in this field. Clinical testing of PHB patches as pericardial substitutes is warranted in cardiac surgery when pericardial closure is desired.

Animals↗
PubMed1992

Telepathology in Sweden. A national study including all histopathology and cytology laboratories.

Quality improvement and standardization of diagnosis in histopathology and cytology are important for the future of the discipline. Nominal scale diagnoses dominate the practice and their standardization depends on relevant and reproducibly identifiable criteria as well as on communication of these among pathologists. Telepathology, i.e. the transmission of adequately detailed colour images of microscopic fields over the telephone network is now a realistic possibility. All 30 laboratories for histopathology and cytology in Sweden will have access to Telepathology work stations for at least 8 weeks each during 1992-1993. Two centers will have permanent stations from September 1992. The images will be transmitted over the ISDN network, allowing a compressed image to appear instantaneously. This image is then gradually and imperceptibly decompressed during 15-60 seconds, the time depending on the complexity of the image. A program for consultation and quality testing is being set up, which will be evaluated during 1993. Based on a recognition of the conditions for diagnosis in pathology and cytology indicated above, the Swedish Society of Pathology has initiated a project called "Telepathology in Sweden". It is a joint effort with active participation by Swedish Telecom and the Swedish Planning and Rationalization Institute for the Health and Social Services, Stockholm as well as by Innovativ Vision AB, Linköping, a company providing hard- and software for image analysis, image banks and communication.

Cell Biology↗
PubMed1992

Prevention of postoperative pericardial adhesions by closure of the pericardium with absorbable polymer patches. An experimental study.

Pericardial adhesions after cardiac operations are a widely known phenomenon. They may severely complicate reoperations, making reentry hazardous, increasing bleeding, and prolonging the operation time. The anatomic orientation and visibility of both bypass grafts and coronary arteries are also impaired. With the aim of minimizing pericardial adhesions after cardiac operations, we studied the course of tissue regeneration after implantation of a new absorbable patch made from poly-hydroxy-butyrate. A total of 23 sheep were studied. Of these, 18 formed the test group and five served as control animals. The animals were killed at intervals of 2 to 30 months after the operation. In 14 of the 18 test animals no adhesions developed. In three animals loose adhesions were found, and in one with signs of postoperative infection there were moderate, generalized adhesions. All control sheep showed moderate adhesions; no infection was noted in this group. Light microscopy in the test group revealed a layer of mesothelium-like cells facing the epicardial side; this was already present in the early specimens. Poly-hydroxy-butyrate appeared to be slowly phagocytosed by polynucleated macrophages, which were still found occasionally in the late samples. Lymphocytes and platelets were rare. Scanning electron microscopy showed, on the epicardial side of the regenerated tissue, a mesothelium-like lining that completely covered the underlying collagen layer. The surface cell morphology grossly resembled that of native pericardium. It was concluded that in this animal model poly-hydroxy-butyrate pericardial patches decreased adhesions and preserved coronary anatomy. The findings in the control group demonstrated that pericardial surgery in the sheep was associated with adhesion formation.

6-Ketoprostaglandin F1 alpha↗
PubMed1992

[Reparative effects of ACE inhibitors on the heart].

Diastolic dysfunction is often present in patients with arterial hypertension. It is not only the consequence of an increased left ventricular muscle mass but also due to a progressive fibrosis of the cardiac interstitium. Experimental studies have shown a close relationship between the degree of interstitial cardiac fibrosis and the activity of the renin-angiotensin system (RAS). Reversal of collagen deposition can be induced by inhibition of the RAS. The purpose of this study was to evaluate the therapeutic potential of ACE inhibitors not only in lowering blood pressure in patients with essential hypertension, but also in normalizing an impaired diastolic filling pattern in the left ventricle. Monotherapy with a single dose of 2.5-5 mg Cilazapril for a period of 6 months was effective in reducing mean arterial blood pressure by about 10 mmHg over the entire 24-h interval. The main reduction occurred throughout the day, but lower blood pressure values during the night were hardly affected at all. The pre- and post-treatment values of the 24-h blood pressure were subjected to a modified Fourier analysis, which did not reveal any disturbances in the circadian blood pressure rhythm by the ACE inhibitor. Left ventricular mass, as calculated from echocardiographic measurements, was reduced by 30% after 6 months of treatment. The degree of regression of LV hypertrophy was closely related to the drug-induced fall in mean arterial pressure. The abnormal left ventricular filling pattern before treatment with a predominance of the late diastolic filling period was corrected by 6 months of ACE inhibitor treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Rings of anionic amino acids as structural determinants of ion selectivity in the acetylcholine receptor channel.

To gain an insight into the molecular basis of the weak but significant selectivity among alkali metal cations of the nicotinic acetylcholine receptor (AChR) channel, we have determined single-channel conductance and permeability ratios for alkali metal cations on specifically mutated Torpedo californica AChR channels expressed in Xenopus oocytes. The mutations involved charged and polar side chains in the three anionic rings (extracellular, intermediate and cytoplasmic ring) which have previously been found to determine the rate of K+ transport through the AChR channel. The results obtained reveal that mutations in the intermediate ring exert much stronger effects on ion selectivity than do mutations in the extracellular and the cytoplasmic ring. The experimental results, together with simulations of the channel's energy profile, suggest that the amino acid residues forming the intermediate ring come into close contact with permeating cations and possibly represent part of the physical correlate of the postulated selectivity filter in the AChR channel.

Amino Acid Sequence↗
PubMed1991

Determination of DNA ploidy and ABH antigen reactivity in both frozen and formalin-fixed bladder tumor tissue.

In a prospective series of patients with transitional-cell bladder carcinomas, DNA ploidy and ABH antigen reactivity were determined in both frozen tissue and formalin-fixed paraffin blocks. ABH antigen measurement in frozen tissue was hampered by methodological problems, especially insufficient morphology, which made quantification difficult. In only 38/55 (69%) cases was the same ABH reactivity found. The knowledge of secretor status was not helpful in the interpretation of these results. In 53/59 (90%) cases the same DNA ploidy was achieved, resulting in good correlation between flow cytometric DNA measurements in formalin-fixed and frozen tissue. The deviations occurred mainly in cases exhibiting a tetraploid DNA profile. DNA assessments using image cytometry on imprints of fresh tissue was a rapid and reliable method in our hands, with identical results being obtained in 32/36 (89%) cases.

ABO Blood-Group System↗