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Biomedical subjects

K Miller

Publications and source records attributed to K Miller.

At least 505 records · Page 28Linked to original sources

Therapeutic factors within in-patient and out-patient psychotherapy groups. Implications for therapeutic techniques.

Therapeutic factors operative in in-patient and out-patient therapy groups were compared. These settings differ greatly, both in terms of the patient population they serve and the overall systems within which they operate. The study revealed significant differences between the therapeutic factors operative in these two settings, and suggested that clinicians should modify their techniques for running psychotherapy groups across settings, to take account of these findings.

Altruism↗

The nasal polyps as a tool for basic research in cystic fibrosis.

Total RNA and mRNA were prepared from cystic fibrosis (CF) and control nasal polyps and nasal epithelial cells. Genomic clones from the chromosomal region of the CF locus were screened by northern blots. A representative cDNA library from nasal polyps was cloned in the vector lambda gt10. For the construction of a physical genomic map around the CF locus single gene markers were isolated from metaphase 1:7q2qter chromosomes by laser micro-dissection and subsequent microcloning. A linkage study with the polymorphic markers met-H, met-D, and pJ3.11 was performed in 53 German CF families with at least 2 children. No significant correlation of any haplotype on the CF chromosomes with the clinical severity of the course of the disease could be observed, which provides evidence that cystic fibrosis is genetically homogeneous.

Chromosome Mapping↗

Scorecards of trauma.

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Emergency Medical Services↗

On-board docs.

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Emergency Medical Services↗

Heparin-induced thrombocytopenia and thromboembolism in the postoperative period.

The heparin-induced thrombocytopenia and thrombosis (HITT) syndrome is associated with hemorrhage as well as development of systemic thrombosis. A case is presented in which a posthepatectomy patient had probable heparin-induced thrombocytopenia complicated by venous thrombosis and pulmonary emboli after receiving low doses of heparin as line flushes. HITT is reviewed and factors related to its successful management in this postoperative patient are analyzed in detail.

Adenocarcinoma↗

[Electrohydraulic shockwave lithotripsy with ventral shockwave exposure--technic, indications and initial clinical results].

Shockwave lithotripsy of ureteral or calyceal calculi covered by the bony pelvis and of anteriorly located stones, such as calculi in horseshoe kidneys or the common bile duct, requires ventral introduction of the shockwave into the body. Eleven patients underwent ESWL in the prone position for the aforementioned indications. All treatments were performed with the Dornier HM3 lithotripter, which allows prone positioning of the patient without technical modification of the stretcher. ESWL was successful in all patients, one requiring a second session for complete stone disintegration. Thus, the possibility of shockwave lithotripsy with the patient in the prone position allows further extension of the indications for noninvasive treatment of calculi.

Gallstones↗

[Use of electronic data processing in the urologic clinic and practice--possibilities and perspectives].

The development, present status and future trends in the use of computers in urology in the Federal Republic of Germany are reviewed. The hardware, software required for hospital and private practice and the staff needed are discussed. Proposals are given for the installation and stepwise upgrading of computer systems, from simple text processing units to complex hospital communication systems. Finally new technologies that might considerably change the use of computers in urology are presented.

Computers↗

Repair of O6-alkylguanine during DNA synthesis in murine bone marrow hematopoietic precursors.

O6-Alkylguanine, a DNA adduct formed by nitrosoureas, becomes the site of a point mutation during DNA synthesis by preferentially base mispairing with thymine rather than correctly base pairing with cytosine. To repair this adduct, cells contain a limited amount of O6-alkylguanine-DNA alkyltransferase (alkyltransferase), a protein which removes the alkyl group in a stoichiometric reaction. To prevent mutations, repair must occur before DNA replication takes place. Consequently, formation of point mutations is related inversely to the number of alkyltransferase molecules and directly to the rate of DNA synthesis. Bone marrow hematopoietic precursors, the target for nitrosourea-induced leukemia, are deficient in alkyltransferase activity. We questioned whether regenerating bone marrow is more susceptible to nitrosoureas than other organs due to persistently low levels of alkyltransferase activity during periods of increased cell proliferation and DNA synthesis. Following syngeneic bone marrow transplantation, murine hematopoietic cells underwent rapid cell proliferation but alkyltransferase activity remained well below the activity in liver. After N-nitrosomethylurea exposure, [3H]thymidine incorporation in rat bone marrow increased 3-fold and stem cell proliferation over 10-fold within 2 days of exposure, but alkyltransferase activity remained low. The relative susceptibility of bone marrow to mutagenic damage from O6-alkylguanine adducts was determined by comparing the ratio of alkyltransferase activity to [3H]thymidine incorporation in marrow, kidney, and liver. In untreated animals, the ratio was lowest in bone marrow and decreased further 48 h after N-nitrosomethylurea exposure to only 21% that of kidney and 1% that of liver. Thus, proliferating hematopoietic precursors appear more likely to form point mutations following nitrosourea exposure than other rodent tissues because they undergo rapid proliferation soon after DNA damage and before O6-alkylguanine adducts can be repaired. The combination of rapid cell proliferation and low DNA repair capacity may be the mechanism of nitrosourea induced leukemic transformation of the bone marrow.

Animals↗

Complex chromosome rearrangements and congenital anomalies.

Congenital complex chromosome rearrangements (CCR) compatible with life are rare in man. Thus patients with CCR usually present considerable diagnostic difficulties both clinically and cytogenetically. We studied a 12-year-old mentally retarded male with minor congenital anomalies as described below and his first-degree relatives. The propositus had an unbalanced karyotype with eight break points and seven derivative chromosomes; two deletions, del(6) (q25----qter) and del(14) (q31----qter), and four translocations, t(2;11), t(5;15), t(6;11), t(6;20) were present. Parental chromosomes were normal; however, the mother had a few metaphases with abnormal chromosomes suggestive of chromosome instability. These findings and a review of reported patients with CCR are presented with regard to speculations about etiology, pathogenesis, phenotypic expression, and prognosis. Physicians should be aware of CCR and broader indications for cytogenetic studies appear warranted in view of these data.

Abnormalities, Multiple↗

Unique mosaicism in Prader-Labhart-Willi syndrome--a contiguous gene or aneuploidy syndrome?

A 16-year-old boy with Prader-Labhart-Willi syndrome (PLWS) had hypotonia, feeding difficulties, failure to thrive, strabismus and bilateral inguinal hernias with cryptorchidism during infancy followed by hyperphagia, marked early-onset obesity with insulin-dependent diabetes mellitus and necrobiosis lipoidica diabeticorum, short stature, hypogonadotropic hypogonadism and some of the facial characteristics of the individuals with the PLWS. IQ is estimated around 90. Cytogenetic studies showed mosaicism: 45,X, t(Y;15) with partial deletion 15 (15pter----15q12); 46,X, t(Y;15), dic (15)(15pter----15q12::15q12----15pter) and 47, X, t(Y;15), dic(15), dic(15). The dic(15) was bisatellited, NOR-positive on both arms and represented inv dup(15). Thus, the 2 lines with the dic(15) showed partial trisomy 15 (15pter----15q12) and partial pentasomy 15 (15pter----15q12), respectively. The cell line ratios were different in lymphocyte and fibroblast cultures. The unique cytogenetic findings in this patient, the reports of a variety of chromosome 15 aberrations in PLWS, as well as aberrations of other chromosomes, suggest that the condition is a contiguous gene syndrome rather than an aneuploidy syndrome.

Adolescent↗

Localisation of the protein and glycoprotein components of bovine nasal epithelial desmosomes by immunoelectron microscopy.

Desmosomal proteins (dp1-4) and glycoproteins (dg1-3) have been localised within desmosomes of bovine nasal epithelium by immunogold labelling of ultrathin frozen sections. Beginning in the extracellular space and proceeding through the plaque to the tonofilaments, the following localisations were found. Labelling for the 130,000 and 115,000 Mr glycoproteins (dg2 and dg3) was predominantly in the extracellular space, a location consistent with their proposed adhesive function. The glycoproteins of 175,000-164,000 Mr (dg1) were also found in the extracellular space and in addition had cytoplasmic domains extending throughout the cytoplasmic plaque. The 83,000 Mr protein (dp3) was located along the cytoplasmic face of the membrane and extended into the plaque, whereas an antibody which recognises both the 83,000 Mr protein (dp3) and the 75,000 Mr protein (dp4) gave labelling both in and beyond the plaque. Labelling for the high mol. wt proteins of Mr 250,000 and 215,000 (dp1 and dp2) was largely excluded from the plaque, and was located distally, adjacent to the tonofilaments. Hemidesmosomes could not be labelled with antibodies to dg1-3 or dp3 and 4, but some labelling was obtained with antibody to dp1 and 2.

Animals↗

Chromosomal mosaicism confined to chorionic tissue.

Chorionic villus samples from two healthy pregnant females were obtained for first trimester fetal diagnosis. The karyotypes were 46,XX/47,XX,+3 and 46,XX/47,XX,+15, respectively. In both cases fibroblast cultures after termination of pregnancy were shown to have normal karyotypes.

Adult↗

Practolol inhibits human skin fibroblast cell mat hydroxyproline accumulation.

Despite being poorly absorbed practolol (N-4-2-hydroxy-3-(1-methyl-ethyl)-amino propoxy phenyl acetamine) inhibited the accumulation of cell mat hydroxyproline, a measure of collagen synthesis, by human skin fibroblasts (DT2PH) in vitro, (ID50 0.8 X 10(-3) M). The degree of inhibition was dependent on the concentration of practolol used and the incubation time. Neither preinitiation of collagen synthesis nor omitting ascorbic acid from the incubation medium modified this inhibitory action. In contrast, in vitro generated metabolites of practol, using normal and aroclor induced hamster liver preparation, and structural analogues of practolol had no effect on cell mat hydroxyproline levels. Related compounds, propranolol, (1-(isopropylamino)-3(1-naphthyl-oxy)2-propranolol), and paracetamol, (N-(4-hydroxyphenyl)acetamide), both inhibited hydroxyproline levels. Fibroblasts derived from uninvolved skin of a psoriasis patient (PS1) were several fold more sensitive to practolol and propranolol than cells derived from normal skin but showed little change in sensitivity towards paracetamol.

Cells, Cultured↗

The predictive value of in-vitro techniques in acute non-lymphocytic leukemia.

Bone marrow aspirates obtained from 27 patients with acute non-lymphocytic leukemia (ANLL) was cultured at the time of presentation, during remission and at relapse. Growth patterns were assessed throughout the patient's clinical course. The percentage of Ia-positive progenitor cells was assayed by a complement-dependent cytotoxicity assay. The percentage of cells in S phase was measured by a tritiated thymidine suicide index. Growth patterns of leukemic bone marrow samples at presentation showed varied numbers of clusters but only rare colonies. This was not predictive of clinical course. Growth patterns of bone marrow in complete remission from ANLL often had depressed colony numbers. However, some patients in remission had bone marrow growth patterns that approached or reached normal colony numbers, suggesting elimination of residual leukemia. The percentage of cells that expressed Ia antigen at presentation, during remission and at relapse varied widely and was not predictive of long-term remission or early relapse. The percentage of cells in S phase was also highly variable and not predictive of clinical course. At presentation the S-phase percentage correlated with the percentage of cells expressing Ia antigen. However, there was no such correlation during remission.

Acute Disease↗

Naturally acquired tolerance to dietary antigen: effect of in utero and perinatal exposure on subsequent humoral immune competence in the rat.

Inbred PVG strain rats were used to investigate the effects of dietary exposure to ovalbumin during the early stages of development on the subsequent induction of ovalbumin-specific antibody responses. An ovalbumin-containing diet was administered to rats during pregnancy and/or for scheduled periods during lactation. All offspring were weaned onto a conventional diet and subsequently challenged parenterally and/or orally with ovalbumin. The effects of the various feeding regimens on the subsequent reaginic, biliary and serum anti-ovalbumin antibody response were examined. Animals exposed to ovalbumin during gestation and/or the post-partum period presented increased levels of biliary anti-ovalbumin antibody activity yet remained systemically tolerant to this antigen following parenteral challenge. These findings are discussed in relation to possible mechanisms responsible for promoting naturally acquired tolerance to dietary antigens.

Animals↗