The Physiological Effects of Short-term Smoking Cessation in Claudicants

Introduction

Smoking contributes to atherosclerosis and causes significant postoperative morbidity. New antismoking law forces short-term pre-operative abstinence. Demonstrable clinical benefit might motivate complete cessation. Our aim was to determine the effects of 24-hr smoking cessation on cardiorespiratory function and claudication distance.

Methods

Smoking claudicants were randomized to 24hr smoking or abstinence. Following these separate periods, cardiopulmonary exercise testing was performed. Pre- and post-exercise, serum lactate and ankle brachial pressure index (ABPI) were measured. During exercise, cardiorespiratory function, initial and absolute claudication (IC, AC) distances and visual analogue scores (VAS) of pain were recorded.

Results

16 patients completed both tests. IC, AC and VAS were unchanged with abstinence ( P = .43, .66, .96, .83). ABPI drop post-exercise was unchanged with abstinence ( P = .08, .09). Cardiorespiratory function was not affected by smoking cessation.

Conclusion

Cardiorespiratory function and claudication symptoms are unchanged following 24-hr smoking cessation., No deterioration in respiratory function is important when considering anaesthetic administration. However, lack of symptomatic improvement may discourage patients from abstaining. Further investigation should determine correlation between short-term abstinence and postoperative morbidity.

Characterisation of copia-like retrotransposons in oil palm ( Elaeis guineensis Jacq.)

The work aimed to isolate and characterise copia-like sequences from Elaeis guineensis. Thirty-two different RT (reverse transcriptase) sequences were isolated from a single oil palm genome using degenerate primers. Extreme sequence heterogeneity was observed. The DNA and protein sequences were assigned to three different classes (A, B, C) on the basis of bootstrapping. We estimated the copy number of the three different classes by using a dot-blot analysis. The comparative results suggest that class-B RT sequences occur at a higher copy number in Cocos nucifera than in Elaeis guineensis and E. oleifera. Class-C RT sequences, which comprise the bulk of isolated sequences, occur in much higher copy number in Elaeis guineensis than in Cocos nucifera, and E. oleifera. Class-A sequences, which have low copy number in Elaeis guineensis and Cocos nucifera, are not present in E. oleifera. Our preliminary results suggest that class-C sequences represent about 5% of the E. guineensis genome, class B, 1% and class A, 0.1%. The methylation status of genomic domains specified by the RT probes was analysed using two pairs of restriction enzymes, each pair having the same recognition sites but different methylation sensitivities ( MspI, HpaII and Sau3AI, MboI). Results from these experiments showed clearly that the genomic domains specified by the RT probes are methylated. These also suggest that a higher copy number appears to correlate to a higher degree of methylation. Our preliminary results suggest that copia-like retrotransposons, because of their ubiquity and diversity, have great potential as genetic markers for plant genome and biodiversity analysis in E. guineensis.

Effects of radiation on a model of malignant glioma invasion

We sought to characterize the effects of radiation alone and in combination with BCNU and dexamethasone on malignant glioma invasion. A model of malignant glioma invasion into a gel matrix of collagen type I was used to characterize response to radiation treatment for four malignant glioma cell lines (C6, U251, U373, A172) and nine primary human glioblastoma explants. A radiation dose dependent inhibition of invasion was noted for the C6 astrocytoma cell line but not the other cell lines or explants. Addition of BCNU and dexamethasone to radiation produced additional inhibition of invasion among the cell lines and explants but could not suppress invasion entirely.

Hand washing awareness: a community health initiative

Handwashing, so simple but forgotten in this busy, hectic, modern world. As perioperative nurses, handwashing is part of our everyday routine. The Ottawa Regional Operating Room Nurses Association brought this important message to the community through our "Back to Basics Health Awareness" Campaign described herein.

Characterisation of the possible effect on birthweight following frequent prenatal ultrasound examinations

The objective of this study was to evaluate and characterise by study of newborn biometry a possible effect on birthweight which we observed previously in a randomised controlled trial of multiple prenatal ultrasound examinations. A total of 2743 women with single pregnancies had been allocated at random to either a protocol of ultrasound imaging and continuous wave Doppler studies at 18, 24, 28, 34 and 38 weeks gestation (intensive group), or to a protocol of a single imaging examination at 18 weeks and further imaging scans only as clinically indicated (regular group). When compared with those in the regular group, and adjusted for other confounding variables, normally formed babies of term gestational age in the intensive group tended to be shorter when measured at birth (P = 0.123) and on day 2-3 of age (P = 0.068). There were statistically insignificant reductions in the circumferences of the chest, abdomen and mid-arm; and in the skinfold thicknesses of the triceps, parascapular and subscapular regions. Principal component analysis showed a trend for a reduction for the skeletal component (P = 0.085) but not for the soft tissue component (P = 0.332). Comparison of the neonatal biometry in the two groups is not conclusive, but the differential effects on the various growth parameters suggest that if multiple scans do indeed restrict fetal growth, the mechanism is more likely to be an effect on bone growth rather than a reduction in nutrient supply from the placenta.

Penetration and shear strength of cement-bone interfaces in vivo

Using sham replacement of the proximal femur in adult mongrel dogs, shear strength at the interface between polymethylmethacrylate bone cement and cancellous bone has been found to be linearly dependent on the depth of penetration of the cement into the bone. Shear strength at the interface was increased by 82% and penetration by 74% when distal bone plugging, pressure lavage, and pressurized insertion of cement were employed. Use of a lower-viscosity cement gave a further 18% increase in penetration and shear strength. There was no film of blood at the cement-bone interface with pressurized insertion of Simplex P and Palacos R cements.

Revision of cemented fixation and cement-bone interface strength

Interfacial shear strength between poly(methyl methacrylate) (PMMA) bone cement and cancellous bone was measured in bone samples from human proximal femora. Samples were prepared with fresh cement-bone, fresh cement inside a mantle of existing cement and with fresh cement-revised bone surfaces. Push-out tests to measure shear strength caused failure only at bone-cement interfaces; revised bone interfaces were 30 per cent weaker (P < 0.02) than primary interfaces. The clinical relevance is that revision of cemented joint arthroplasties may necessitate removal of components with sound cement-bone fixation. The practice of removing all traces of PMMA cement may not yield the optimal fixation; adhesion of fresh cement to freshly prepared surfaces of the existing cement might also be considered where circumstances are favourable.

An algometer for the automated measurement of pain threshold

An automated device is described which enables operator independent measurement of pain threshold. Pressure is applied across a joint of the digit by means of a controlled pneumatic actuator. Testing 10 normal subjects indicated good reproducibility (r2 = 0.75, one-way analysis of variance).

The effect of total hip replacement on driving reactions

The driving reactions of 25 patients were assessed before and after operation for hip replacement. Driving reactions were tested by monitoring the delay and force of brake application after an emergency signal, using a simulated driving control system. Fifteen normal subjects were also tested. Statistical analysis demonstrated significant differences between patients with either left or right hip replacement and between pre- and postoperative testing. Most patients improved by the eighth week, but some had deteriorated and did not recover until re-tested eight months after operation. It is concluded that for most patients eight weeks' delay for return to driving is appropriate, but for a minority of patients with right hip replacement recovery of reaction speed requires longer rehabilitation.

5-FU infusion in advanced colorectal cancer: a comparison of three dose schedules

Ninety-four patients with advanced colorectal adenocarcinoma were treated by continuous iv 5-FU infusion on three different dose schedules. Thirty-three patients received a 72-hour infusion of 5-FU (30 mg/kg/24 hours) every 3 weeks (Group A); 31 received a 72-hour infusion of 5-FU (30 mg/kg/24 hours) every 2 weeks (Group B); and 30 received a 48-hour infusion of 5-FU (30 mg/kg/24 hours) every week (Group C). Although this was a sequential nonrandomized study of the dose schedules, the groups were comparable with respect to various prognostic factors. Response rates were as follows: Group A--three patients had minor response (9%) and 30 had no response (91%); Group B--five patients achieved partial response (16%), nine had minor response (29%), and 17 had no response (55%), and Group C--one patient achieved complete response (3%), eight achieved partial response (27%), five had minor response (17%), and 16 had no response (53%). The median survival time for Group A was 9 months, for Group B was 9.5 months, and for Group C was 14 months. Intensifying the dose schedule of 5-FU by increasing the frequency of administration has significantly improved response rates. A prolongation of the median survival time of patients treated with a 48-hour infusion at 1-week intervals was noted, although this was not statistically significant.

Somatostatinoma--the most recently described pancreatic islet cell tumor

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Energy transfer between the carotenoid and the bacteriochlorophyll within the B-800-850 light-harvesting pigment-protein complex of Rhodopseudomonas sphaeroides

Energy transfer between carotenoid and bacteriochlorophyll has been studied in isolated B-800-850 antenna pigment-protein complexes from different strains of Rhodopseudomonas sphaeroides which contain different types of carotenoid. Singlet-singlet energy transfer from the carotenoid to the bacteriochlorophyll is efficient (75-100%) and is rather insensitive to carotenoid type, over the range of carotenoids tested. The yield of carotenoid triplets is low (2-15%) but this arises from a low yield of bacteriochlorophyll triplet formation rather than from an inefficient triplet-triplet exchange reaction. The rate of the triplet-triplet exchange reaction between the bacteriochlorophyll and the carotenoid is fast (Ktt greater than or equal to 1.4 . 10(8) S-1) and also relatively independent of the type of carotenoid present.

Posterior paralysis of unknown etiology causing total loss in a large turkey flock

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