Diabetes mellitus and open heart surgery

A method, based on bedside determinations of blood glucose by nursing staff, was designed to control the administration of insulin to diabetic patients during and following open heart surgery. A computer-controlled intravenous infusion pump was used to deliver the insulin. Excellent control of the hyperglycaemia normally associated with open heart surgery was achieved, with 84 percent of measured blood glucose values falling within 2 mmol/litre of the target value of 6 mmol/litre. The method proved to be simple, effective, and safe.     

Influence of surface morphology on in vitro bacterial adherence to central venous catheters

The detailed surface topography of five poly-urethane centralvenous catheters (CVC) (Hydrocath, Deltacath, Certofix trio,Arrow-Howes and Multicath three) was examined by scanning electronmicroscopy and laser profilometry. The results were correlatedwith the ability of Staphylococcus epidermidis to adhere toeach CVC. Hydrocath CVC had the smoothest surface, as determinedby profile peak values of 0.17 µm (Ra) and 0.94 µm(Rz). These CVC also had the lowest number ofstaphylo-cocciadhering to the surface. In contrast, Certofix trio CVC hadan irregular surface (Ra 1.29µm and Rz 6.35 µm)which was confirmed by scanning electron microscopy. These latterCVC had significantly more bacteria colonizing their surfacecompared with Hydrocath and Arrow-Howes CVC (P < 0.01). Theresults suggest that a CVC with a smooth surface, absent ofsurface defects, may reduce the risk of colonization with bacteriaand therefore subsequent sepsis. (Br. J. Anaesth. 1994; 72:587–591)     

A COMPARISON OF α2-ADRENORECEPTOR BINDING CHARACTERISTICS OF INTACT HUMAN PLATELETS IDENTIFIED BY [3H]-YOHIMBINE AND [3H]-DIHYDROERGOCRYPTINE

• 1 The binding characteristics of [³H]-yohimbine on intact human platelets were investigated and compared to those of [³H]-dihydroergocryptine.
• 2 A significant correlation (r = 0.92, P<0.01, n = 7) was observed between the inhibition of [³H]-yohimbine binding and of noradrenaline-induced platelet aggregation, indicating that [³H]-yohimbine binds to the α2-adrenoreceptor responsible for noradrenaline-induced platelet aggregation.
• 3 The binding capacity of [³H]-yohimbine in 20 young male volunteers was 39 ± 2.2 fmol/10⁸ platelets (mean ± s.e.m.). This is considerably lower than the binding capacity of [³H]-dihydroergocryptine previously reported.
• 4 Simultaneous analysis of [³H]-yohimbine and [³H]-dihydroergocryptine binding in 10 subjects showed a significantly lower binding capacity for [³H]-yohimbine (P<0.001, paired t-test). This difference was not present in every subject, and was consistent within individuals on repeated testing.
• 5 Possible causes of this difference in radioligand binding are discussed.

     

Expression of urokinase-type plasminogen activator in the mucosal lesions of inflammatory bowel disease

The expression of plasminogen activators was analysed in mucosal homogenates from inflammatory bowel disease patients to determine whether the urokinase-type (u-PA) is implicated in the pathogenesis of mucosal tissue injury. Homogenates of mucosal biopsy tissue from ulcerative colitis, Crohn's disease, infectious colitis and normal control patients were subjected to polyacrylamide gel electrophoresis. The types of plasminogen activator present were detected by zones of lysis in a fibrin-agarose gel overlay. All the tissues studied displayed tissue plasminogen activator activity (t-PA). In ulcerative colitis, 18 of the 19 diseased colon biopsies, but none of six biopsies from uninvolved areas of the same colon, showed u-PA activity. Similar results were found in 12 Crohn's disease patients. Biopsies from the infectious colitis group and from radiation colitis patients also showed both u-PA and t-PA activity. The age, sex, duration of disease, and presence and type of treatment did not affect u-PA expression in the inflamed mucosa. The results suggest that u-PA may be implicated in the mediation of tissue injury in the inflamed intestinal mucosa.     

The effect of thrombopoietin on the proliferation and differentiation of murine hematopoietic stem cells

In this study, we explored whether thrombopoietin (Tpo) has a direct in vitro effect on the proliferation and differentiation of long-term repopulating hematopoietic stem cells (LTR-HSC). We previously reported a cell separation method that uses the fluorescence-activated cell sorter selection of low Hoescht 33342/low Rhodamine 123 (low Ho/low Rh) fluorescence cell fractions that are highly enriched for LTR-HSC and can reconstitute lethally irradiated recipients with fewer than 20 cells. Low Ho/low Rh cells clone with high proliferative potential in vitro in the presence of stem cell factor (SCF) + interleukin-3 (IL-3) + IL-6 (90% to 100% HPP-CFC). Tpo alone did not induce proliferation of these low Ho/low Rh cells. However, in combination with SCF or IL-3, Tpo had several synergistic effects on cell proliferation. When Tpo was added to single growth factors (either SCF or IL-3 or the combination of both), the time required for the first cell division of low Ho/low Rh cells was significantly shortened and their cloning efficiency increased substantially. Moreover, the subsequent clonal expansion at the early time points of culture was significantly augmented by Tpo. Low Ho/low Rh cells, when assayed in agar directly after sorting, did not form megakaryocyte colonies in any growth condition tested. Several days of culture in the presence of multiple cytokines were required to obtain colony-forming units-megakaryocyte (CFU-Mk). In contrast, more differentiated, low Ho/high Rh cells, previously shown to contain short- term repopulating hematopoietic stem cells (STR-HSC), were able to form megakaryocyte colonies in agar when cultured in Tpo alone directly after sorting. These data establish that Tpo acts directly on primitive hematopoietic stem cells selected using the Ho/Rh method, but this effect is dependent on the presence of pluripotent cytokines. These cells subsequently differentiate into CFU-Mk, which are capable of responding to Tpo alone. Together with the results of previous reports of its effects on erythroid progenitors, these results suggest that the effects of Tpo on hematopoiesis are greater than initially anticipated.     

Hypertension in dialysis and kidney transplant patients

For the first time, the Canadian Hypertension Education Program has studied the evidence supporting blood pressure control in people requiring renal replacement therapy for end-stage kidney disease, including those on dialysis and with renal transplants. According to the Canadian Organ Replacement Registry’s 2008 annual report, there were an estimated 33,832 people with end-stage renal disease in Canada at the end of 2006, an increase of 69.7% since 1997. Of these, 20,465 were on dialysis and 13,367 were living with a functioning kidney transplant. Thus, it is becoming more likely that primary care practitioners will be helping to care for these complex patients. With the lack of large controlled clinical trials, the consensus recommendation based on interpretation of the existing literature is that blood pressure should be lowered to below 140/90 mmHg in hypertensive patients on renal replacement therapy and to below 130/80 mmHg for renal transplant patients with diabetes or chronic kidney disease.     

Adolescents with type 1 diabetes and risky behaviour

Aim: The aim of the student is to assess whether adolescents with type 1 diabetes mellitus (T1DM) in Italy differ from their healthy peers in regard to risky behaviour. Methods: Data were collected from 215 patients, aged 14 ± 2 years with a mean disease duration of 7 ± 5 years. The control group was comprised of 464 healthy adolescents recruited among high school students. Each patient completed an anonymous confidential questionnaire to determine the prevalence of sexual behaviour, alcohol and tobacco consumption, illicit drug use, and, among patients with diabetes and frequency of mismanagement related to diabetes care. Results: Compared with controls, subjects with diabetes showed a similar rate of sexual intercourse among males and lower rates among females (34.8% vs 35.5%, p NS and 29.4% vs 41.4%, p < 0.05, respectively). Males in the diabetes group reported a higher rate of tobacco use, whereas females showed similar or higher rates of use for every illicit drug studied. Among patients with diabetes, those who are engaged in risky behaviour showed a higher rate of treatment mismanagement (76% vs 34%, p < 0.01). Conclusion: Adolescents with T1DM are as likely as their healthy peers to engage in risky behaviour, indicating the potential benefit of anticipatory guidance concerning glycaemic control and increased risk of acute and chronic complications.