Transcellular Passage of Neisseria gonorrhoeae Involves Pilus Phase Variation

Piliated and nonpiliated Neisseria gonorrhoeae organisms were added on top of confluent layers of HEC-1-B cells, each maintained on a microporous Transwell-COL membrane. The bacteria released into the lower chamber were characterized with respect to the following virulence determinants: pili, which mediate adherence to target host cells; PilE, the major pilus subunit protein; and PilC, which is involved in pilus biogenesis and adherence. Even if >99% of the added bacteria of N. gonorrhoeae MS11 were piliated, bacteria recovered on the other side of the cell layer were predominantly nonpiliated. The recovered clones still expressed unassembled PilE protein, but 50% had lost PilC production. Nonpiliated gonococci, in which the 5′ end of pilE had been deleted, were released in reduced numbers, and piliated recA bacteria added to the cell layer were not released at all, at time points when piliated recA⁺ clones were found at high numbers in the lower chamber. Our data indicate that bacteria producing unassembled PilE protein are selected for during passage through an epithelial cell layer. The finding that the pilE gene sequence was altered in the transmigrants suggests that pilin sequence variation is involved in the transcellular passage of N. gonorrhoeae.     

Neurotensin-like Peptides in the CNS of Lampreys: Chromatographic Characterization and Immunohistochemical Localization with Reference to Aminergic Markers

Neurotensin (NT)-like peptides in the CNS of the lamprey Lampetra fluviatilis were studied by radioimmunoassay (C-terminal specific NT antiserum), reverse-phase HPLC and immunohistochemistry. Multiple peaks of NT-immunoreactive (-ir) material were observed upon HPLC, of which a major peak eluted in the position of bovine NT. Immunofluorescence histochemistry showed that a monoclonal antibody recognizing the N-terminal (1 - 11) fragment of NT, as well as two polyclonal NT antisera labelled a large number of cell bodies in the periventricular area of hypothalamus, including the postinfundibular commissural nucleus and the ventral and dorsal hypothalamic nuclei. Additional groups of NT-ir cells were observed in the preoptic nucleus, the postoptic commissural nucleus, the mesencephalic tegmentum (L.fluviatilis), and in the spinal cord (L.fluviatilis and Ichtyomyzon unicuspis). Dense NT-ir fibre plexuses were present in the caudal hypothalamus, corpus striatum, ventral mesencephalon, and in the dorsal horn and lateral margin of the spinal cord. At the ultrastructural level the lateral spinal margin showed NT-ir terminal structures, which in most cases were not associated with synaptic specializations, although occasional synaptic contacts with unlabelled elements were found. The relation between NT-ir and monoamine-containing cells was examined with immunofluorescence double-staining, using antisera to tyrosine hydroxylase (TH), 5-hydroxytryptamine (5-HT), and histamine respectively. In the periventricular nuclei of hypothalamus numerous TH-, 5-HT-, as well as histamine-ir cells were located in close association with NT-ir cells, but none of the aminergic markers could be detected within NT-ir neurons. The chemical properties as well as the anatomical distribution of lamprey NT-like peptides show several similarities with those present in mammals, suggesting that NT-containing neuronal systems in the CNS developed early in vertebrate phylogeny.     

Evidence for the existence of two forms of α2A-adrenoceptors in the rat

Summary The _2A-adrenoceptors in rat spleen, kidney, spinal cord and cerebral cortex were studied using [³H]-RX821002 radioligand binding. In the spleen, spinal cord and cerebral cortex, the ligand bound to saturable sites with a K _d of about 1 nmol/l and capacities of 134, 240 and 290 fmol/mg protein, respectively. Computer modelling competition curves for 39 drugs, including those for _2A-, _2B- or _2C-adrenoceptor selective drugs, indicated that the sites labelled by [³H]-RX821002 in the spleen consisted of a single population of _2A-adrenoceptors. However, the competition curves for guanoxabenz were definitely biphasic and resolved into two site fits, indicating that guanoxabenz was binding to both high affinity (K _d = 35 nmol/1) and low affinity (K _d = 8900 nmol/1) _2A-adrenoceptor sites in the proportions 57% and 43%, respectively. The K _d ^Sfor a number of ₂-adrenoceptor subtype selective drugs, measured in competition with [³H]-RX821002 in cerebral cortex and spinal cord, were highly correlated with those obtained in the spleen indicating their _2A-adrenoceptor nature. However, by contrast to the results with the spleen, the guanoxabenz competition curves for the spinal cord and cerebral cortex were monophasic and resolved only into one site fits, the K _d of guanoxabenz being about 4000 nmol/l for both tissues. Drug K _d ^Sfor kidney _2A-adrenoceptors were also determined using [³H]-RX821002. For nearly all drugs tested, the K _d ^Swere highly correlated with those found for the _2A-adrenoceptors in the other rat tissues. However, for guanoxabenz, the data indicated that it competed with [³H]-RX821002 at a single _2A-adrenoceptor site with a K _d of 39 nmol/1. When the rat _2A-adrenoceptor gene RG20 was transiently expressed in COS-7 cells and its ligand binding properties probed using [³H]-RX821002, the drug K _d ^Sobtained were also highly correlated with those found for the _2A-adrenoceptors in the spleen, cerebral cortex, spinal cord and kidney of the rat. For the RG20 encoded receptor, the guanoxabenz competition curves were steep and monophasic and modelled best into one site fits, with the Kd of guanoxabenz being 5200 nmol/1.It is suggested that guanoxabenz can differentiate between two forms of _2A-adrenoceptors in the rat: _2A1 and _2A2. The _2A1-form is present in the spleen and kidney where it shows a high apparent affinity for guanoxabenz. The _2A2-form shows a low apparent affinity for guanoxabenz and is present in the spleen, cerebal cortex and spinal cord. The _2A2-form of the rat ₂-adrenoceptor appears to be encoded by the RG20 gene. The _2A, and _2A2-adrenoceptor forms do not represent high and low affinity receptor forms for agonists because assays included EDTA, Gpp(NH)p and Na⁺, which eliminated the high affinity receptors for agonists.     

Interspecies differences in the kinetic properties of deoxycytidine kinase elucidate the poor utility of a phase I pharmacologically directed dose-escalation concept for 2-chloro-2′-deoxyadenosine

2-Chloro-2-deoxyadenosine (CdA, Cladribine), is a purine antimetabolite currently under investigation in phase II clinical trials for the treatment of lymphoid malignancies. Significant differences in CdA toxicity between mice and humans were observed during phase I clinical evaluation. For the elucidation of interspecies differences in drug toxicity the pharmacokinetics of CdA after subcutaneous injection and the kinetic properties of the CdA-phosphorylating enzyme, deoxycytidine kinase (dCK), were compared in mice and humans. The ratio of the dose lethal to 10% of mice (LD₁₀) to the maximum tolerated dose (MTD) in humans was 50 and the ratio of the area under the curve obtained at approximately one-half the LD₁₀ (AUC_{approx. one-half the LD 10})/AUC_MTD was 49. A significant interspecies difference was observed in the kinetic properties of dCK, the main CdA-activating enzyme. With CdA as a substrate, the Michaelis constant (K _m) of dCK in crude extracts of mouse thymus was 10 times higher than that in human thymus. An approximately 9-fold interspecies difference in maximum velocity (V_max)/K _m indicated a higher efficiency of dCK for CdA in humans than in mice. The peak plasma concentration was 210 times higher and exceeded theK _m in mice. Initial and terminal half-lives were approximately 7 times shorter in mice and trough levels were similar in mice and humans. Thus, the differences in AUCs at equitoxic doses are largely explained by differences in the target enzyme properties and the pharmacokinetic pattern. The observed lower tolerance for CdA in humans as compared with mice confirms the view that antimetabolites may not be good candidates for pharmacokinetically guided dose-escalation schemes unless detailed information on interspecies variability in drug bioactivation is available.     

Diagnostic outcome of repeated mammography screening

Mammographic screening for breast cancer within health service routines was evaluated for the years 1987–1992, with special focus on repeated screening during 1989–1992. The overall attendance rate by women aged 40 to 74 years was 82.8%. During 1989–1992 malignancy was found in 2.6/1000 screened women, giving a 87.4% positive predictive rate at surgery and 95.9% efficiency. Among women aged 45, the positive predictive rate was >94%. Fine-needle aspiration (FNA) biopsy showed invasive cancers in 84% and highly suspected cancer in another 15%; 60% of the lesions were nonpalpable. For first-time (prevalence) screening (1987–1988) the positive predictive rate was 86% and the malignancy yield 6.4/1000. In women aged 40–44 years there were few surgical referrals (1.6%), but the positive predictive rate at surgery was only 48.3%, indicating diagnostic difficulties in young women. The median size of all invasive cancers was 12 mm: 84% were classified as pT1, and 23% had lymph node involvement. Stage II disease was found in 27% of all malignancies. The use of FNA in the diagnostic workup for breast cancer screening is of crucial importance to the maintenance of high positive predictive rates at surgery. Moreover, regular analysis is important even when mammographic screening is incorporated into the routine work of health services.

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Resumen El tamizaje mamográfico para cáncer del seno como parte de las rutinas de los servicios de salud fue evaluado para los años 1987–1992, con especial énfasis en el tamizaje repetido en el período 1989–1992. La tasa de cumplimiento por parte de las pacientes en las edades 40–74 años fue de 82.8%. En 1989–92 se halló neoplasia maligna en 2.6/1000 mujeres tamizadas, lo cual significó un índice de predicción de positividad en la cirugía de 87.4% y de eficiencia de 95.9%. Entre las mujeres con edad 45 años el valor de predicción de positividad fue >94%. La biopsia por aspiración con aguja fina demostró cánceres invasores en 84% y alta sospecha de cáncer en un 15% adicional; 60% de las lesiones fueron no palpables. En el tamizaje de primera vez (prevalencia, 1987–1988) el valor de predicción de positividad fue de 86% y el rendimiento de 6.4/1000. En las mujeres con edades 40–44 años se hicieron menos referencias para cirugía (1.6%) pero el valor de predicción de positividad en la cirugía fue apenas de 48.3%, lo cual indica dificultades diagnósticas en las pacientes más jóvenes. El tamaño promedio de los cánceres invasores fue 12 mm; 84% fueron clasificados como pT1 y 25% presentaban invasión ganglionar; 27% de todos los tumores malignos fueron estado II. La aspiración con aguja fina en la evaluación diagnóstica del tamizaje para cáncer mamario es de importancia crucial para el mantenimiento de un alto valor de predicción de positividad en la cirugía y el análisis regular es importante aun cuando el tamizaje mamográfico quede incorporado en el trabajo rutinario de los servicios de salud.

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Résumé Le dépistage systématique des cancers du sein par mammographie effectuée par les services de santé a été évalué entre 1987–1992, en particulier le dépistage répété pratiqué entre 1989–1992. Le taux de participation des femmes âgées entre 40–74 ans a été de 82.8%. Dans la période 1989–1992, une tumeur maligne a été retrouvée chez 2.6/1000 femmes, la chirurgie permettant de calculer une valeur prédictive positive de 87.4% et une efficacité de 95.9%. Chez les femmes âgées de plus de 45 ans, la valeur prédictive positive a dépassé 94%. La ponction biopsie a fourni la preuve de cancer invasif dans 84% des cas et celle d'une forte suspicion dans 15% des cas, alors que 60% des lésions n'étaient pas palpables. Par comparaison, la valeur prédictive positive pendant la période de dépistage entre 1987–88 a été de 96% pour une prévalence de cancer de 6.4/1000. Chez la femme âgée entre 40–44 ans, très peu de femmes ont été opérées, avec une valeur prédictive positive de 48.3%, ce qui démontre les difficultés de diagnostic chez la femme jeune. La taille médiane de tous les cancers invasifs était de 12 mm: 84% étaient classés comme pT1 et 23% avaient un envahissement lymphatique. On a trouvé un stade II chez 27% des patientes tous cancers confondus. L'utilisation de ponction biopsie est capitale pour le diagnostic de cancer de sein pour maintenir une valeur prédictive positive élevée lors de la chirurgie et une analyse régulière est nécessaire même lorsque le dépistage systématique par mammographie est inclu dans le programme des service de santé.

     

Cadmium in kidneys in Swedes measured in vivo using X-ray fluorescence analysis

An X-ray fluorescence (XRF) technique using plane polarized X-rays for excitation was used for in vivo measurements of cadmium in the kidney cortex among non-occupationally exposed members of the general population in southern Sweden. The measured concentrations of cadmium in the kidney cortex of smokers (median 28 g/g, n = 10) were significantly higher (P = 0.0036) as compared to those in non-smokers (median 8 g/g, n = 10), and so were the cadmium concentrations in blood and urine. The results show that smoking considerably increases the cadmium concentration in the kidney cortex and that smoking is a major source of cadmium exposure in the general population of Sweden. Except in the presence of very deeply situated kidneys, where the minimum detectable concentration is high, non-invasive in vivo XRF analysis of kidney cadmium should be a useful tool for evaluating the effects of long-term low-level exposure to cadmium and the risk of kidney damage.     

Male Reduction Mammaplasty After Vertical Banded Gastroplasty

Background: Breast reduction surgery is common in females; however, in males it is mainly due to gynecomastia. After weight reduction following obesity surgery, it is a problem in women, but also in some men. Method: One patient is described in whom the weight reduction declined from BMI 52 to BMI 36 after vertical banded gastroplasty, giving the patient ptotic breasts. Results: The patient underwent reduction mammaplasty with lateral single-based cutaneous flaps, and a total of 1,000 g was removed. Conclusion: Reduction mammoplasty can be performed in males with the methods used today, after successful weight loss following obesity surgery.     

Combination chemotherapy of the epipodophyllotoxin derivatives,Teniposide and Etoposide

Summary Previous studies in vitro on the influence of extracellular protein binding of Teniposide (VM26) and Etoposide (VP16-213) on subsequent cellular uptake by experimental murine tumor cells [Cancer Res 38: 2549 (1978); Drug Metab Rev 8: 119 (1978)] suggested that a timed-sequential combination of VM26 and VP16-213 may increase the bioavailability of VP16-213. This was studied clinically in six cancer patients with ascites (five ovarian, one rectal) whereby VM26 (20 mg/m²) was given i.p. 2 h prior to VP16-213 (100 mg/m²; i.p.). In some patients, this regimen was administered i.v. The i.v. regimen was found to be more toxic (myelosuppression, nausea, vomiting) than i.p. regimen at same doses of drugs. Several patients remained stable to disease during 1–2 courses of therapy (3 weeks per course), one patient had partial remission, and has been stable in her disease for more than 4 months.In two patients, plasma and ascites fluid was analyzed for VP16-213 and VM26 by a new reverse-phase high performance liquid chromatography method. Both VM26 and VP16-213 could be eluted isocratically (28% v/v acetonitrile in water) from a c₁₈ column with retention times of 6.6 and 13.3 min, respectively. Subsequent pharmacokinetic analysis of one patient suggests that protein binding displacement of VP16-213 in plasma and perhaps ascites fluid increased the pharmacokinetic volume of distribution (28 l) and reduced the elimination half-life (12 h). The data suggests that VP16-213 is distributed more widely in the body and is represented by a single compartment pharmacokinetic model. Analysis of VM26 in ascites and plasma suggests that the so-called deep pharmacokinetic compartment represents ascites equivalent space and that the plasma concentration represents VM26 as free and protein-bound drug in kinetic distinguishable compartments.Determinants of drug action are potentially composed of a multiplicity of physiological, biochemical, and other factors. The potential for manipulating the pharmacodynamic properties of drugs to achieve greater therapeutic potential needs further study.     

Actions of Competence in Occupational Therapy Practice: A phenomenological study of practice in narrative form

This study examined the phenomenon ?what are occupational therapists doing when they feel competent?. Data were provided by eleven occupational therapists who narrated clinical cases in which they had felt themselves to be competent. The empirical phenomenological psychological (EPP) method was used to analyse and interpret the data. The result revealed that on a general level the experience of feeling competent as an occupational therapist derived from achieving results in the rehabilitation project that were satisfying for both participants (the therapist and the client). The strategies for accomplishing this were related to the empathic competence of the therapists. This competence involved interpreting clinical situations as well as understanding the relationship between motive, meaning, decision and time. Further it involved bringing objects, in the form of adaptations, technical aids, structures, simplifications or compensations, into the clinical situation. These abilities together had a great impact on the therapeutic outcome by shaping the clients' lifeworld to make it richer and more active.