Minimally invasive saphenous vein harvesting: effects on endothelial and smooth muscle function

BACKGROUND

The long saphenous vein remains the commonest conduit used in coronary artery bypass grafting procedures. Surgical trauma during vein harvesting can cause endothelial and smooth muscle injury that has important implications for vein graft longevity. Minimally invasive vein harvesting is advocated to reduce wound morbidity. However, the functional consequences of increased handling and traction, with potentially detrimental effects, remain unknown.

METHODS

Forty patients were prospectively randomized into either a minimally invasive (minimal) or traditional (open) saphenous vein harvest group. Smooth muscle contractile function was assessed by responses to potassium chloride and phenylephrine. Endothelial cell function was assessed by responses to serial escalations in concentration of acetylcholine, bradykinin, calcium ionophore, sodium nitroprusside, and N-nitro-L-arginine using isometric tension studies.

RESULTS

Harvest times were similar for both groups. The total incision length in the minimal group was significantly shorter than in the open group. There were no differences in smooth muscle contractions to either receptor-independent or receptor-mediated agonists between the two groups. Similarly, vasorelaxation in response to both endothelium-dependent and endothelium-independent agonists were similar in both groups.

CONCLUSIONS

Minimally invasive saphenous vein harvesting is associated with similar medial smooth muscle and endothelial function as open harvesting. These findings suggest that minimally invasive harvesting techniques can be used without major detrimental effects on vascular integrity.

Generation of Regionally Specified Neurons in Expanded Glial Cultures Derived from the Mouse and Human Lateral Ganglionic Eminence

The specific identity of neuronal precursors within the embryonic brain is, at present, not clear. Here we show that cultures with glial characteristics derived from the embryonic mouse or human lateral ganglionic eminence (LGE) can be expanded over many passages and maintain their glial identity. Interestingly, removal of serum and EGF from the culture medium results in the generation of large numbers of neurons. The neurons derived from these cultures display many characteristic features of striatal neurons, which normally derive from the LGE, even after extensive expansion in vitro. Furthermore, a portion of the neurons generated in these cultures were shown to arise from glial fibrillary acidic protein (GFAP)-expressing cells. These results demonstrate that at least a subpopulation of neurogenic LGE precursors exhibit glial characteristics.

Rigid, cross-conjugated macrocycles: a cyclic alternative to 4,4'-bipyridines in supramolecular chemistry

[structure: see text]. The synthesis of two fully conjugated, rigid macrocyclic analogues to 4,4'-bipyridine is described. The use of these macrocycles in self-assembly processes is demonstrated by axial coordination to metalloporphyrins, and one system (R = Me) has been characterized by single-crystal X-ray crystallography.

Provision of platelet support for fetuses and neonates affected by severe fetomaternal alloimmune thrombocytopenia

Severe fetomaternal alloimmune thrombocytopenia requires urgent treatment with compatible platelet concentrates. As prompt treatment is sometimes delayed owing to the unavailability of compatible platelets, we established an accredited platelet donor panel to provide effective and timely transfusion support for fetal and neonatal therapy. After a mass screening programme of over 60,000 blood donations, 45 HPA-1a-negative donors with no antibodies to HPA, HLA, red cell antigens and granulocytes/lymphocytes, and with low titre anti-A and/or -B were accredited. All accredited donors were fully genotyped for HPA-1, -2, -3 and -5 by PCR-SSP. Ninety-one per cent of the accredited donors were also negative for HPA-5b.

Effects of an external nasal dilator on the work of breathing during exercise

PURPOSE

The effect of an external nasal dilator on the work of breathing (WOB) was measured during exercise in 14 untrained college students (age, 23 +/- 2.7 yr).

METHODS

Two maximal, incremental ergometer tests were performed to exhaustion. Subjects wore a placebo or an active nasal dilator strip, in random order, during each test. An esophageal balloon was placed through each of the subject's mouth into the esophagus for measurement of inspiratory elastic work (INEW), inspiratory resistive work (INRW), and expiratory resistive work (EXRW). Subjects breathed through a Hans Rudolph(R) face mask that covered both the mouth and nose during both tests. Measured variables included oxygen uptake (VO2), ventilation (VE), tidal volume (VT), frequency of breathing (f), INEW, INRW, and EXRW (work expressed in joules). An alpha level was set at P < 0.05.

RESULTS

No significant differences were found in INEW, INRW, and EXRW between conditions at 70% of VO2max (mean +/- SD; Placebo: INEW, 25.6 +/- 17.8 J.min-1; INRW, 22.4 +/- 15.8 J.min-1; EXRW, 16.7 +/- 12.3 J.min-1; Active: INEW, 24.7 +/- 12.9 J.min-1; INRW, 19.7 +/- 11.9 J.min-1; EXRW, 15.2 +/- 8.6 J.min-1; P > 0.05). No difference was found in INEW, INRW, and EXRW at maximal exercise between conditions (mean +/- SD; Placebo: INEW, 50.2 +/- 29.9 J.min-1; INRW, 67.3 +/- 42.3 J.min-1; EXRW, 102.3 +/- 78.4 J.min-1; Active: INEW, 45.7 +/- 19.6 J.min-1; INRW, 62.6 +/- 36.7 J.min-1; EXRW, 86.3 +/- 50.9 J.min-1; P > 0.05). There were no differences in VO2, VE, VT, or f between conditions.

CONCLUSION

Wearing an external nasal dilator does not significantly reduce the work of breathing during exercise.

Emergency redo mitral valve replacement in a 27-year-old pregnant female with a clotted prosthetic mitral valve, preoperative fetal demise and postoperative ventricular assist device: a case report

A 27-year-old Laotian woman with a St Jude mechanical mitral valve became pregnant, requiring a change in her anticoagulant after the first trimester when her warfarin sodium (coumadin) was replaced with enoxaparin sodium (lovenox). Her prosthetic valve clotted and became dysfunctional. She was 16 weeks pregnant and was taken to the operating room for emergency surgery for replacement of the valve. The fetus had not been viable for 1-2 weeks, but still remained in utero. The clotted valve was replaced with another St Jude valve of a slightly smaller diameter (27 mm). The patient could not be weaned from bypass so a right ventricular assist device (RVAD) was inserted. The patient was weaned from the RVAD after 2 days of support. Two days following removal of the RVAD the fetus spontaneously aborted. The patient had a long, complicated hospital course and was discharged 3 months later. She subsequently died 4 months after discharge of a cerebral hemorrhage from excessive anticoagulation.

A comparison of methods for measuring socio-economic status by occupation or postal area

Seven methods of estimating socio-economic status (SES) were compared, including four based on data specific to individuals (Blishen, Pineo-Porter, British Registrar General, Hollingshead) and three based on the average characteristics of the postal code area in which people live (income alone, education alone, income and education combined). Data from the files of 151 patients undergoing in vitro fertilization were used. The four individual scales were highly correlated among themselves (Spearman's correlation coefficient between 0.6 and 0.9) but only moderately correlated with the measures based on postal code (Spearman's correlation coefficient between 0.2 and 0.3).

Employment outcomes among AFDC recipients treated for substance abuse in Washington State

In 1996, Congress passed sweeping welfare reform, abolishing the Aid to Families with Dependent Children (AFDC) program. Each state now administers its own welfare-to-work program under broad federal guidelines, which require eligible adult recipients to work or perform community service. High-risk welfare recipients, especially those with chemical dependency problems, face significant obstacles in their efforts to achieve greater self-sufficiency under the new welfare-to-work programs. State databases were used to track employment outcomes for AFDC clients admitted to treatment for chemical dependency in Washington State during a two-year period. Exposure to treatment was associated with a greater likelihood of becoming employed and with increased earnings for those who became employed. Ensuring that welfare recipients with substance abuse problems have access to appropriate treatment and vocational services is critical if welfare-to-work programs are to promote greater economic self-sufficiency.

Nud1p links astral microtubule organization and the control of exit from mitosis

The budding yeast spindle pole body (SPB) not only organizes the astral and nuclear microtubules but is also associated with a number of cell-cycle regulators that control mitotic exit. Here, we describe that the core SPB component Nud1p is a key protein that functions in both processes. The astral microtubule organizing function of Nud1p is mediated by its interaction with the gamma-tubulin complex binding protein Spc72p. This function of Nud1p is distinct from its role in cell-cycle control: Nud1p binds the spindle checkpoint control proteins Bfa1p and Bub2p to the SPB, and is part of the mitotic exit network (MEN) in which it functions upstream of CDC15 but downstream of LTE1. In conditional lethal nud1-2 cells, the MEN component Tem1p, a GTPase, is mislocalized, whereas the kinase Cdc15p is still associated with the SPB. Thus, in nud1-2 cells the failure of Tem1p to interact with Cdc15p at the SPB probably prevents mitotic exit.

High-pressure suction drainage via a polyurethane foam in the management of poststernotomy mediastinitis

BACKGROUND

This study was performed to evaluate the effectiveness of suction drainage in the management of early poststernotomy mediastinitis.

METHODS

From September 1998 to August 1999, we encountered nine cases of poststernotomy mediastinitis out of 1,209 adult median sternotomies performed in this time period. All these cases were treated with suction drainage, which was recently introduced to our management protocol. From September 1997 to August 1998, we encountered 11 cases of poststernotomy mediastinitis of 1,343 adult median sternotomies. All these cases were initially treated by closed drainage and irrigation, which was our previous first-line management. We used the latter group as historical controls for the evaluation of suction drainage. Lengths of hospitalization were compared using the Mann-Whitney U test, and success versus failure of the primary treatment was compared using the chi2 test.

RESULTS

Treatment with the suction dressing resulted in a decreased length of hospitalization after treatment starts (p = 0.02) and a lower rate of treatment failure (p = 0.03).

CONCLUSIONS

The use of high-pressure suction drainage is a valuable adjunct in the early management of poststernotomy mediastinitis.

Best practices for the prevention and treatment of pressure ulcers

In this article, the Canadian Association of Wound Care puts forward 12 recommendations for best practices in the prevention and treatment of pressure ulcers that focus on an interdisciplinary patient-centered approach. These recommendations are a synthesis of the Agency for Health Care Policy and Research guidelines, European guidelines, and current literature as interpreted by the Canadian experience and achieved through a national consensus panel. The article concludes that best practice guidelines must be fluid documents that respond to new evidence and experience.

Issues for the coming age of continuous glucose monitoring

PURPOSE

This article reports the results of a symposium in which diabetes educators considered and discussed issues that are likely to arise when continuous glucose monitoring (CGM) becomes available and readily accessible.

METHODS

Fifteen certified diabetes educators and 5 others with complementary expertise participated in a discussion based on their responses to 11 questions designed to elicit perspectives on issues related to CGM. Issues for discussion and debate include those related to patient acceptance and lifestyle, implications for professional practice and reimbursement, concerns about professional liability, use of CGM data by insurers and payers, and CGM data transfer.

RESULTS

Educators offered varied and sometimes conflicting responses to CGM-related issues.

CONCLUSIONS

Awareness of CGM-related issues will likely become an important part of diabetes professional development and perspectives in practice. Identifying and framing the issues before the new technologies become available allow diabetes educators to participate proactively in structuring the emerging policies, procedures, and standards of care.

Preparing the wound bed--debridement, bacterial balance, and moisture balance

Successful diagnosis and treatment of patients with chronic wounds involve holistic care and a team approach. The integration of the work of an interdisciplinary care team that includes doctors, nurses, and allied health professionals with the patient, family, significant others, and caregivers offers an optimal formula for achieving wound resolution. Such an approach challenges practitioners and everyone participating in wound care to integrate data and information that arise from a number of sources and mitigating factors. In this article, the authors define the changing paradigm that links treatment of the cause and focuses on three components of local wound care: debridement, wound-friendly moist interactive dressings, and bacterial balance. The authors demonstrate that the treatment of chronic wounds can be accomplished through a series of recommendations and rationales based on the literature and their experience. These recommendations lay the groundwork for thorough assessment and evaluation of the wound.

Genetic control of dorsal-ventral identity in the telencephalon: opposing roles for Pax6 and Gsh2

We have examined the genetic mechanisms that regulate dorsal-ventral identity in the embryonic mouse telencephalon and, in particular, the specification of progenitors in the cerebral cortex and striatum. The respective roles of Pax6 and Gsh2 in cortical and striatal development were studied in single and double loss-of-function mouse mutants. Gsh2 gene function was found to be essential to maintain the molecular identity of early striatal progenitors and in its absence the ventral telencephalic regulatory genes Mash1 and Dlx are lost from most of the striatal germinal zone. In their place, the dorsal regulators, Pax6, neurogenin 1 and neurogenin 2 are found ectopically. Conversely, Pax6 is required to maintain the correct molecular identity of cortical progenitors. In its absence, neurogenins are lost from the cortical germinal zone and Gsh2, Mash1 and Dlx genes are found ectopically. These reciprocal alterations in cortical and striatal progenitor specification lead to the abnormal development of the cortex and striatum observed in Pax6 (small eye) and Gsh2 mutants, respectively. In support of this, double homozygous mutants for Pax6 and Gsh2 exhibit significant improvements in both cortical and striatal development compared with their respective single mutants. Taken together, these results demonstrate that Pax6 and Gsh2 govern cortical and striatal development by regulating genetically opposing programs that control the expression of each other as well as the regionally expressed developmental regulators Mash1, the neurogenins and Dlx genes in telencephalic progenitors.

Instructional technology in medical education: lessons learnt

New instructional technologies, especially Web-based applications, may play an increasing role in medical education, particularly for distance and distributed learning. As medical educators turn to this medium, numerous benefits and opportunities, but also challenges and pitfalls, will arise. The successful development and implementation of instructional technologies in medicine require an appreciation of the medium's heterogeneous nature, its strengths, weaknesses and limitations. These in turn rely on partnerships with various experts and the early adoption of evaluation. We have summarized the lessons learnt from developing Web-based courses on palliative care in a framework for adopting instructional technologies. This framework incorporates development, implementation and evaluation.

Obesity management: Australian general practitioners' attitudes and practices

OBJECTIVES

To document general practitioners' (GPs) attitudes and practices regarding the prevention and management of overweight and obesity.

RESEARCH METHODS AND PROCEDURES

A cross-sectional survey of a randomly selected sample of 1500 Australian GPs was conducted, of which 752 questionnaires were returned. The measures included views on weight management, definitions of success, views regarding the usefulness of drugs, approaches to and strategies recommended for weight management, and problems and frustrations in managing overweight and obesity.

RESULTS

GPs view weight management as important and feel they have an important role to play. Although they consider themselves to be well prepared to treat overweight patients, they believe that they have limited efficacy in weight management and find it professionally unrewarding. GPs view the assessment of a patient's dietary and physical activity habits and the provision of dietary and physical activity advice as very important. The approaches least likely to be considered important and/or least likely to be practiced were those that would support the patient in achieving and maintaining lifestyle change.

DISCUSSION

There remains considerable opportunity to improve the practice of GPs in their management of overweight and obesity. Although education is fundamental, it is important to acknowledge the constraints of the GPs' existing working environment.

The Ultracor tilting disc heart valve prosthesis in the aortic position: mid-term follow up

BACKGROUND AND AIM OF THE STUDY

The Ultracor valve is a recent introduction in the evolution of the tilting disc valve. This report summarizes a single surgeon's experience with the valve in the aortic position over a nine-year period.

METHODS

Between 1990 and 1999, 94 patients received an Ultracor heart valve prosthesis in the aortic position. Forty-five patients (48%) had associated procedures, of which 32 (34%) were coronary artery grafts. Mean follow up was 2.6 years; total follow up was 229 patient-years. Follow up was 100% complete.

RESULTS

The actuarial survival rate, including operative mortality rate, at five years was 82%. Actuarial freedom from valve-related death was 96% at five years. The linearized complication rate was 1.7%/year for late valve-related mortality, 1.7%/year for thromboembolism, 2.2%/year for anticoagulant-related hemorrhage (ACH), 1.3%/year for prosthetic valve endocarditis (PVE), and 1.7%/year for reoperation. The estimates of actuarial freedom from complications at five years were thromboembolism 89%, ACH 90%, PVE 96% and reoperation 96%. No structural failure or valve thrombosis was observed.

CONCLUSION

Our experience over nine years showed the Ultracor heart valve prosthesis in the aortic position to be comparable with other currently evaluated mechanical heart valves in terms of durability and clinical results. Further study in this area should concentrate on the impact of valve type on left ventricular recovery post-implantation to provide additional information to the surgeon when selecting a valve from the plethora of choices available.

Immunochemical studies on the putative plasmalemmal receptor for 1, 25-dihydroxyvitamin D(3). III. Vitamin D status

The effect of vitamin D status on levels of the putative 1, 25(OH)(2)D(3) membrane receptor (pmVDR) was studied in chick intestine, kidney, and brain. Western analyses and assays for specific [(3)H]1,25(OH)(2)D(3) binding indicated that, in intestine, pmVDR levels were greatest in -D chicks relative to +1,25D and +D animals (P < 0.05). In kidney, protein levels and specific binding followed the order +D > +1,25D, -D. In brain, vitamin D status did not affect protein levels or specific binding levels. In tissue from normal chicks, both protein and specific binding followed the order of intestine > kidney > brain membranes. Intestinal cells were further evaluated for the effect of 1,25(OH)(2)D(3) on selected "rapid responses." Extrusion of (45)Ca in response to 130 pM 1, 25(OH)(2)D(3) in vitro was greater in cells from -D chicks than from +1,25D or normal birds. Analyses of signal transduction events revealed diminished hormone-induced intracellular calcium oscillations (as assessed by fura-2 fluorescence), and lack of steroid-enhanced protein kinase (PK) A activity in intestinal epithelial cells from -D chicks relative to +D chicks. PK C activation by 130 pM 1,25(OH)(2)D(3) was approximately twofold in cells from +D or -D chicks. The combined results indicate that vitamin D status differentially affects the pmVDR in intestine, kidney, and brain. In intestine, vitamin D deficiency differentially affects (45)Ca handling, intracellular calcium oscillations, PK A and PK C activities in response to 1,25(OH)(2)D(3).

High-performance liquid chromatographic determination of 17beta-estradiol and 17beta-estradiol-3-acetate solubilities and diffusion coefficents in silicone elastromeric intravaginal rings

A rapid, sensitive reversed-phase high-performance liquid chromatographic method has been developed for the determination of in vitro release of 17beta-estradiol and its ester prodrug, 17beta-estradiol-3-acetate, from silicone intravaginal rings. Partial hydrolysis of the acetate under the aqueous conditions provided by the 1% benzalkonium chloride release medium necessitates its conversion to 17beta-estradiol prior to HPLC analysis. Both steroid peaks have been fully resolved from the benzalkonium chloride peaks by the reported chromatographic method, which employs a C18 bonded reversed-phase column, an acetonitrile-water (50:50, v/v) mobile phase and a UV detection wavelength of 281 nm. The peak area versus 17beta-estradiol concentration was found to be linear over the range of 0.0137-1347 microkg ml(-1). The HPLC method has also been used to determine the silicone solubilities and diffusion coefficients of the two related steroids. The almost 100-fold increase in 17beta-estradiol-3-acetate release from the silicone core-type intravaginal rings compared to 17beta-estradiol is shown to be due to a 60-fold increase in silicone solubility and a one and a half-fold increase in diffusitivity. The results demonstrate that an effective estrogen replacement therapy dose of 17beta-estradiol may be administered from a silicone intravaginal reservoir device containing the labile 17beta-estradiol-3-acetate prodrug.