Investigating racial differences in clinical and pathological features of prostate cancer in South African men

BACKGROUND

Men with West African ancestry living in Europe and North America are at higher risk of being diagnosed with prostate cancer, are diagnosed at a younger age, and have more severe disease characteristics. Published reports present a conflicting picture of the disease in sub-Saharan Africa. We aimed to study the clinical and pathological features of men undergoing prostate biopsy from different racial backgrounds in South Africa in an attempt to characterise the disease locally. Our hypothesis was that black African men presenting to our service had more severe disease characteristics than other patients.

METHODS

All patients who underwent a prostate biopsy at Groote Schuur Hospital, Cape Town from July 2008 to July 2014 were studied. For each patient, data were collected on age, self-assigned race, presenting symptoms, prostate-specific antigen (PSA) level, prostate volume, and histological diagnosis.

RESULTS

A total of 1016 patients were studied. 162 (15.9%) were black and 854 (84.1%) were coloured (mixed ancestry), white, or Asian. Black patients were compared as a group to the coloured, white and Asian patients. The black patients in the series had higher PSA values (mean 167.8 vs 47.7, median 16.4 vs 10.9, p < 0.001), were more likely to be diagnosed with cancer (57.4% vs 44.5%, p = 0.003), were more likely to present with locally advanced cancer (T3/4 16.1% vs 8.9%, p = 0.028), and were more likely to have high grade disease (Gleason ≥ 8 45.2% vs 30.5%, p = 0.011). There was no difference in age, presenting symptoms, or prostate volume.

CONCLUSION

The black men diagnosed with prostate cancer at Groote Schuur Hospital had significantly worse clinical and pathological characteristics than the non-black men. Interpreting these differences as representative of a more common or aggressive disease among black men is not possible due to study limitations.

Intravenous Glycopyrrolate and Atropine at Induction of Anaesthesia: A Comparison1

In unpremedicated patients presenting for general anaesthesia for electroconvulsive therapy (ECT), the use of atropine combined with methohexitone as an intravenous induction agent was found to produce a significantly greater increase in heart rate than glycopyrrolate in similar combination. There was no difference in the antisialogogue effect of the two drugs at the doses used, and both drugs provided similar protection against the effects of suxamethonium and ECT on heart rate.

Effect of amputation level on the stress transferred to the femur by an artificial limb directly attached to the bone

Attachment of an artificial limb directly to the skeleton has a number of potential benefits and the technique has been implemented for several amputation sites. In this paper the transfer of stress from an external, transfemoral prosthesis to the femur during normal walking activity is investigated. The stress distribution in the femur and at the implant-bone interface is calculated using finite element analysis for the 3D geometry and inhomogeneous, anisotropic material properties obtained from a CT scan of a healthy femur. Attachment of the prosthetic leg at three different levels of amputation is considered. Stress concentrations are found at the distal end of the bone and adjacent to the implant tip and stress shielding is observed adjacent to the implant. It is found that the stress distribution in the femur distal to the epiphysis, where the femur geometry is close to cylindrical, can be predicted from a cylindrical finite element model, using the correct choice of bone diameter as measured from a radiograph. Proximal to the lesser trochanter the stress decreases as the femur geometry diverges significantly from a cylinder. The stress concentration at the distal, resected end of the bone is removed when a collared implant is employed. These findings form the basis for appropriate settings of an external fail-safe device to protect the bone from excessive stress in the event of an undue load.

Spatiotemporal multi-resolution approximation of the Amari type neural field model

Neural fields are spatially continuous state variables described by integro-differential equations, which are well suited to describe the spatiotemporal evolution of cortical activations on multiple scales. Here we develop a multi-resolution approximation (MRA) framework for the integro-difference equation (IDE) neural field model based on semi-orthogonal cardinal B-spline wavelets. In this way, a flexible framework is created, whereby both macroscopic and microscopic behavior of the system can be represented simultaneously. State and parameter estimation is performed using the expectation maximization (EM) algorithm. A synthetic example is provided to demonstrate the framework.

A data-driven framework for neural field modeling

This paper presents a framework for creating neural field models from electrophysiological data. The Wilson and Cowan or Amari style neural field equations are used to form a parametric model, where the parameters are estimated from data. To illustrate the estimation framework, data is generated using the neural field equations incorporating modeled sensors enabling a comparison between the estimated and true parameters. To facilitate state and parameter estimation, we introduce a method to reduce the continuum neural field model using a basis function decomposition to form a finite-dimensional state-space model. Spatial frequency analysis methods are introduced that systematically specify the basis function configuration required to capture the dominant characteristics of the neural field. The estimation procedure consists of a two-stage iterative algorithm incorporating the unscented Rauch-Tung-Striebel smoother for state estimation and a least squares algorithm for parameter estimation. The results show that it is theoretically possible to reconstruct the neural field and estimate intracortical connectivity structure and synaptic dynamics with the proposed framework.

Sputum proteomics in inflammatory and suppurative respiratory diseases

RATIONALE

Markers of inflammatory activity are important for assessment and management of many respiratory diseases. Markers that are currently unrecognized may be more valuable than those presently believed to be useful.

OBJECTIVES

To identify potential biomarkers of suppurative and inflammatory lung disease in induced sputum samples.

METHODS

Induced sputum was collected from 20 healthy control subjects, 24 patients with asthma, 24 with chronic obstructive pulmonary disease, 28 with cystic fibrosis (CF), and 19 with bronchiectasis. Twelve patients with CF had sputum sampled before and after antibiotic therapy for an infective exacerbation. The fluid phase of induced sputum was analyzed by surface-enhanced laser desorption/ionization time-of-flight (SELDI-TOF) mass spectroscopy on three protein array surfaces. Some protein markers were selected for identification, and relevant ELISA assays sought. For 12 patients with CF, both SELDI-TOF and ELISA monitored changes in inflammatory responses during infective exacerbations.

MEASUREMENTS AND MAIN RESULTS

SELDI-TOF identified potential biomarkers that differentiated each of the disease groups from healthy control subjects: at a significance of P < 0.01, there were 105 for asthma, 113 for chronic obstructive pulmonary disease, 381 for CF, and 377 for bronchiectasis. Peaks selected for protein identification yielded calgranulin A, calgranulin B, calgranulin C, Clara cell secretory protein, lysosyme c, proline rich salivary peptide, cystatin s, and hemoglobin alpha. On treatment of an infective CF exacerbation, SELDI-TOF determined falls in levels of calgranulin A and calgranulin B that were mirrored by ELISA-measured falls in calprotectin (heterodimer of calgranulins A and B).

CONCLUSIONS

Proteomic screening of sputum yields potential biomarkers of inflammation. The early development of a clinically relevant assay from such data is demonstrated.

Moving from CFC aerosol to HFA aerosol or dry powder inhalers: what do patients think?

BACKGROUND/OBJECTIVES

Environmentally friendly hydrofluoroalkane (HFA) pressurised metered-dose inhalers are currently being marketed to replace chlorofluorocarbon (CFC)-driven devices. It is uncertain whether these new formulations with different properties are acceptable to patients. Similarly, switching a patient to a dry powder inhaler (DPI) carries the risk of non-acceptance.

METHODS

One hundred patients with obstructive airway disease on regular CFC aerosol inhaler medication underwent a standardised, structured interview. During the interview patients were asked to use a new HFA aerosol inhaler and three DPIs in random order. Patients' notions were recorded.

RESULTS

Most patients (96) agreed to change from their CFC to the HFA inhaler, of those, only 12 did so with some reservation. Properties (taste, user-friendliness, design) of the HFA inhaler were rated favourably. DPIs represented an acceptable alternative to aerosol inhalers. In fact, 57 patients preferred a DPI over the HFA inhaler. Not all powder devices were equally acceptable. Replacing the CFC inhaler with patients' preferred alternative devices resulted in a more than 3-fold increase in costs.

CONCLUSION

Concerns about the acceptability of reformulated CFC-free aerosol inhalers are ill founded. However, if given the choice, many patients prefer a DPI over the HFA inhaler. The transition offers an opportunity to review patients' current treatment and the proficiency of their inhaling technique. Moving to CFC-free inhalers will have revenue implications.

Pharmacology and biological efficacy of a recombinant, humanized, single-chain antibody C5 complement inhibitor in patients undergoing coronary artery bypass graft surgery with cardiopulmonary bypass

BACKGROUND

Cardiopulmonary bypass (CPB) induces a systemic inflammatory response that causes substantial clinical morbidity. Activation of complement during CPB contributes significantly to this inflammatory process. We examined the capability of a novel therapeutic complement inhibitor to prevent pathological complement activation and tissue injury in patients undergoing CPB.

METHODS AND RESULTS

A humanized, recombinant, single-chain antibody specific for human C5, h5G1.1-scFv, was intravenously administered in 1 of 4 doses ranging from 0.2 to 2.0 mg/kg before CPB. h5G1.1-scFv was found to be safe and well tolerated. Pharmacokinetic analysis revealed a sustained half-life from 7.0 to 14.5 hours. Pharmacodynamic analysis demonstrated significant dose-dependent inhibition of complement hemolytic activity for up to 14 hours at 2 mg/kg. The generation of proinflammatory complement byproducts (sC5b-9) was effectively inhibited in a dose-dependent fashion. Leukocyte activation, as measured by surface expression of CD11b, was reduced (P<0.05) in patients who received 1 and 2 mg/kg. There was a 40% reduction in myocardial injury (creatine kinase-MB release, P=0.05) in patients who received 2 mg/kg. Sequential Mini-Mental State Examinations (MMSE) demonstrated an 80% reduction in new cognitive deficits (P<0.05) in patients treated with 2 mg/kg. Finally, there was a 1-U reduction in postoperative blood loss (P<0. 05) in patients who received 1 or 2 mg/kg.

CONCLUSIONS

A single-chain antibody specific for human C5 is a safe and effective inhibitor of pathological complement activation in patients undergoing CPB. In addition to significantly reducing sC5b-9 formation and leukocyte CD11b expression, C5 inhibition significantly attenuates postoperative myocardial injury, cognitive deficits, and blood loss. These data suggest that C5 inhibition may represent a novel therapeutic strategy for preventing complement-mediated inflammation and tissue injury.

Anticoagulation is unnecessary after biological aortic valve replacement

BACKGROUND

Opinion differs as to whether anticoagulation is beneficial in preventing ischemic stroke in the early postoperative period after biological aortic valve replacement (AVR). The purpose of this study was to determine whether early anticoagulation with heparin and warfarin confers any significant advantage for patients undergoing such replacement.

METHODS AND RESULTS

Patients undergoing biological AVR between 1987 and 1996 were divided retrospectively into 2 groups based on their postoperative anticoagulation. Group A (109 patients) received heparin followed by warfarin for 3 months (prothrombin time, 20 to 25 seconds). Group B (76 patients) received no postoperative anticoagulation. Patients were followed for cerebral ischemic events, bleeding, repeat operation, hospital stay, and survival. There were 5 (4.6%), 3 (2.8%), and 12 (11%) postoperative cerebral ischemic events for group A at time points of < 24 hours, 24 hours to 3 months, and > 3 months, respectively; for group B patients, 3 (3.9%), 2 (2.6%), and 9 (11.8%) events were seen during the same respective time periods. There were no statistically significant differences for ischemic events during any of these time periods for the 2 groups. Bleeding complications occurred in 10 (9.2%) group A and 7 (9.2%) group B patients. Mean hospital stay was 12 days for both groups. Repeat operative AVR was required in 6 (5.5%) group A and 7 (9.2%) group B patients. A comparison of Kaplan-Meier survival rates between groups A and B (mean follow-up, 47 +/- 26 and 59 +/- 30 months, for groups A and B, respectively) was not statistically significant (P = 0.60). Survival rates were 93%, 84%, and 62% at 1, 5, and 7 years for group A and 87%, 74%, and 67% for group B, respectively.

CONCLUSIONS

Early anticoagulation after AVR confers no advantage in the prevention of early cerebral ischemic events after biological AVR. No disadvantage in terms of bleeding or prolonged hospital stay was incurred by early anticoagulation. Long-term valve function and survival were not adversely affected by withholding early anticoagulation. We conclude that early anticoagulation after biological AVR is unnecessary.

Low prevalence of primary biliary cirrhosis in Victoria, Australia. Melbourne Liver Group

A prevalence study of primary biliary cirrhosis was carried out in the state of Victoria, Australia, by means of a mail survey of specialist physicians and a review of hospital records. Eighty four cases were identified, giving a prevalence of 19.1 per million population (95% confidence limits (CI) 15.3, 23.7), which is among the lowest in published reports. The prevalence in the Australian born, at risk population (women over the age of 24) was 51 per million (95% CI 37.5, 67.9). Both these figures are considerably lower than those in populations of similar age distribution in the UK and northern Europe. Since most Victorians are descended from British or European settlers, the low prevalence of primary biliary cirrhosis in this study supports the hypothesis that local environmental factors may be important in the pathogenesis of this disease.

Mifepristone (RU 486) compared with high-dose estrogen and progestogen for emergency postcoital contraception

BACKGROUND

Mifepristone (RU 486) is a synthetic steroid with potent antiprogestational and antiglucocorticoid properties that provides an effective medical method of inducing abortion in early pregnancy. Since progesterone is essential for implantation, we tested the use of mifepristone for emergency postcoital contraception.

METHODS

We studied 800 women and adolescents requesting emergency postcoital contraception who had had unprotected intercourse within the preceding 72 hours. A total of 398 women and adolescents were randomly assigned to treatment with 100 micrograms of ethinyl estradiol and 1 mg of norgestrel, each given twice 12 hours apart (standard therapy), and 402 women and adolescents were randomly assigned to receive 600 mg of mifepristone.

RESULTS

None of the women and adolescents who received mifepristone became pregnant, as compared with four of those who received standard therapy; the difference in failure rates between the two regimens was not statistically significant. The number of pregnancies in each group was significantly lower than the number expected according to calculations based on the day of the cycle during which intercourse had taken place (P less than 0.001). In many subjects the stage of the cycle as calculated by menstrual history was inconsistent with measurements of plasma progesterone or urinary pregnanediol excretion. The subjects treated with mifepristone reported less nausea (40 percent vs. 60 percent) and vomiting (3 percent vs. 17 percent) on the day of treatment, as well as lower rates of other side effects, than the subjects treated with the standard regimen, but they were more likely to have a delay in the onset of the next menstrual period (42 percent vs. 13 percent).

CONCLUSIONS

Mifepristone is a highly effective postcoital contraceptive agent that, if used more widely, could help reduce the number of unplanned and unwanted pregnancies.

Biochemical and functional correlates of myocardium-like transformed skeletal muscle as a power source for cardiac assist devices

Skeletal muscles, such as the latissimus dorsi muscle, can be transformed to gain considerable fatigue resistance to be suitable either for cardiomyoplasty, or to power a cardiac assist device. Such transformation of the skeletal muscle can be achieved by low frequency electrical stimulation for several weeks. In this article, we reviewed the stimulation protocol, and subsequent histochemical, biochemical, and functional changes in the skeletal muscle, and compared them to those of the cardiac muscle. The parameters that should be useful for stimulating such a muscle to assist the heart are defined. The issues currently under study, including the optimal transformation parameters, the feasibility of working transformation, and the importance of device design to minimize vascular compromise of the muscle, are also discussed. It is concluded that there is a great potential to use the plasticity of skeletal muscle for clinical purposes, specifically by transforming the skeletal muscle to resemble the myocardium in order to use it either to replace or repair the myocardium, or as the endogenous power source for a cardiac assist device.

The muscle-powered dual-chamber counterpulsator: rheologically superior implantable cardiac assist device

To enable long-term studies of a totally implantable cardiac assist device powered by transformed fatigue-resistant skeletal muscle, we developed a dual-chamber extraaortic counterpulsator implanted, 2 of which fluid for power transfer. Six dogs had our dual-chamber extraaortic counterpulsator implanted, 2 of which had undergone prior transformation of their latissimus dorsi muscle. The blood pump, with a Dacron graft at each end, was anastomosed end-to-side and parallel to the thoracic aorta, allowing continuous blood flow to minimize thrombus formation caused by stasis and turbulence. The blood pump was powered by a hydraulic bulb placed beneath the latissimus dorsi muscle. The latissimus dorsi muscle was stimulated to contract during diastole using a synchronized burst electrical stimulator. The ratio of diastolic pressure time product over systolic time tension index, which reflects the myocardial oxygen supply and demand ratio, was calculated from ascending aortic pressure tracings. A consistent increase in this ratio of 44% in 4 dogs with nontransformed latissimus dorsi muscle and of 70% in 2 dogs with transformed latissimus dorsi muscle was obtained when the device was activated. Preliminary chronic implantation studies using a Medtronic cardiomyostimulator (Model SP1005) as the burst stimulator for our dual-chamber extraaortic counterpulsator produced an average augmentation in aortic diastolic pressure of 34 mm Hg for up to six days. Our results indicate that, with further refinement of this device, a long-term totally implantable cardiac assist device powered by endogenous skeletal muscle will be feasible.

Left ventricular full-thickness cardiomyoplasty with pericardial neoendocardium: experimental development of a surgical procedure

Cardiomyoplasty, a surgical procedure using stimulated skeletal muscle graft to replace or repair damaged myocardium, has been successfully performed in experimental animals and clinical patients. Whenever feasible, endocardium of the damaged myocardial segment is retained and partial-thickness cardiomyoplasty should be carried out. However, if this procedure were to be applied to enlarge a hypoplastic ventricle or to maintain normal dimensions of the ventricular cavity in some repairs in adults, full-thickness replacement of the ventricular wall with contractile skeletal muscle mass would be required. To develop such a technique, several canine experiments were carried out. In 7 dogs, "simple full-thickness cardiomyoplasty" was performed by using a latissimus dorsi muscle graft to repair a full-thickness left ventricular wall defect. We found it was difficult to obtain adequate hemostasis between the nonscarred myocardial tissue and the skeletal muscle graft, and excessive suturing to obtain hemostasis resulted in strangulation of the muscle grafts. The skeletal muscle-blood interface in the left ventricle was found to be highly thrombogenic. The perioperative hemorrhage and the risk of muscle graft strangulation by excessive sutures were avoided by using a pericardial patch as neoendocardium in 5 dogs that underwent similar full-thickness cardiomyoplasty procedures. Although the pericardial neoendocardium was not fully antithrombogenic in this canine model, endothelialization of the endocardium occurred within several weeks after operation. Thus, when combined with an implantable synchronized burst stimulator, this technique may in the future provide an effective "full-thickness dynamic cardiomyoplasty" to enlarge the ventricles and augment myocardial function in select patients.

Is high potassium solution necessary for reinfusions in "multidose" cold cardioplegia? A randomized prospective study using computerized Holter system

Multidose potassium cardioplegia is a common method of myocardial preservation. Although initial potassium arrest conserves high-energy phosphates, there is conflicting evidence that repeat high potassium boluses augment this protection. Fifty-six patients were prospectively randomized to receive multidose cold high potassium cardioplegia (27 mEq of KCl/L) both in the initial and subsequent infusions (Group 1) or an initial cold high potassium (27 mEq/L) cardioplegia followed by boluses of cold low potassium (7 mEq, of KCl/L) solution (Group 2). The two groups were compared in terms of postoperative myocardial electrical stability and hemodynamic performance. Electrocardiograms were recorded by continuous Holter monitor, and the data were analyzed by computer. The duration of aortic cross-clamping and cardiopulmonary bypass did not differ between groups. Group 1, who received more total KCl than Group 2 (p less than .005), experienced more high-grade ventricular ectopia during both reperfusion (p less than .001) and the immediate postoperative period (p less than .001), and required more lidocaine hydrochloride (p less than .001) for arrhythmias. There was no significant difference in hemodynamic performance between the two groups. This study fails to show an advantage to multidose "high potassium" cardioplegia and found a significant increase in ventricular ectopia associated with its use. We advocate using low potassium solutions after initial cold high potassium arrest.

Transforming skeletal muscle for myocardial assist: a feasibility study

Canine experiments were undertaken to determine the feasibility of transforming skeletal muscle for myocardial assistance. Initially, a rectus-muscle pedicle flap was used to power a ventricular assist conduit. A specially designed "pulse-train" stimulator produced skeletal muscle contractions capable of augmenting myocardial function. Statistically significant increases in either systolic or diastolic pressures were achieved by appropriate synchronization and signal delays of the stimulator. Then, the left rectus muscle was conditioned by stimulating it at low frequencies (2 to 10 Hz) for 6 to 12 weeks. The degree of transformation from type II (fast) to type I (slow) fibres was examined and the resultant tolerance to fatigue studied. Preliminary data show that a greater proportion of type I fibres is associated with increased resistance to fatigue. Such transformed skeletal muscle should therefore be more suited to power the cardiac assist devices.

A system for accurate closed reduction and external fixation of fractures

A new external reduction and fixation system has been developed in which the two processes are carried out by two pieces of apparatus - a reducer and a fixator. Schanz pins are inserted into the fractured bone in the conventional way and the reducer, which is free-standing, is placed adjacent to the limb and attached to the pins. During reduction the proximal bone segment remains stationary while the distal segment is moved to realign the bone. Its movements are carried out mechanically by the reducer and each plane is dealt with separately, the bone segment being moved both linearly and in rotation in that plane. Each movement is obtained by turning one of the three handles on the reducer, and is smoothly and rapidly accomplished with complete control. Once the best possible alignment has been achieved a simple, lightweight, single-side fixator is attached to the pins. The reducer is then unfastened and removed.