Total hip arthroplasty for femoral fractures other than capital physeal fractures in dogs: 14 cases (2012-2020)

OBJECTIVES

The goals of this retrospective study were to assess the clinical and radiographic outcomes in dogs with proximal femoral fractures, other than capital physeal fractures, treated via total hip arthroplasty.

MATERIALS AND METHODS

Medical records as well as pre-operative, immediate post-operative and 2 to 3 months post-operative radiographs of 14 dogs with femoral head and neck fractures treated via total hip arthroplasty were reviewed. A Liverpool Osteoarthritis in Dogs questionnaire was completed by owners to assess long-term outcomes.

RESULTS

Seven femoral head fractures, and seven femoral neck fractures were included. Four of the femoral head fractures were acute in nature, the three remaining femoral head fractures and all seven femoral neck fracture cases were chronic fractures. Malorientation of the femoral stem was more common in the chronic femoral fracture cases when compared to the acute femoral fracture cases. Two of the acute fracture cases and five chronic fracture cases experienced a change in femoral stem position post-operatively. One femoral fissure fracture occurred and was repaired intraoperatively. One case had a post-operative complication that resulted in implant removal. All dogs had good to excellent owner-perceived outcome.

CLINICAL SIGNIFICANCE

Femoral head and neck fractures, and in particular the chronic cases, represented a challenging subset of cases presenting for total hip arthroplasty, resulting in suboptimal stem alignment in many cases. However, clinical outcomes were considered good to excellent in all dogs in the study, indicating that total hip arthroplasty is a viable treatment option for these types of fractures.

Teriparatide-associated calciphylaxis: a case series

Calciphylaxis is a rare and potentially fatal small-vessel occlusive disease in which the tunica media becomes calcified, endothelial cells proliferate, and the tunica intima becomes thickened and fibrotic. Calciphylaxis typically occurs in the setting of end-stage renal disease with secondary hyperparathyroidism and elevated calcium-phosphorus product. The estimated incidence of calciphylaxis in dialysis or kidney transplant patients is 1 to 4%; however, the incidence of non-uremic calciphylaxis is unknown. We assessed postmarketing adverse event reports to further characterize cases of calciphylaxis associated with teriparatide. We searched for cases of teriparatide-associated calciphylaxis in the literature (EMBASE, PubMed) and those reported to FDA, including the FDA Adverse Event Reporting System, through March 31, 2021. We included calciphylaxis cases following teriparatide exposure of < 2 years. Twelve cases described teriparatide-associated calciphylaxis. The median age was 81 (range 47-86) years. Eleven cases reported confirmatory biopsy and/or imaging. The median time-to-onset of calciphylaxis following teriparatide initiation was 3.5 (range 1-20) months. Three cases reported hospitalization, of which one resulted in death due to progression of the lesions. All cases had multiple risk factors (mean (SD), 4.5 (1.0)) including concomitant medications associated with calciphylaxis (12), female sex (11), and/or underlying autoimmune disease or other inflammatory disorder (10). We believe that exposure to teriparatide, coupled with underlying risk factors, may have triggered new-onset calciphylaxis. Expedited diagnosis and management by a clinician are important because calciphylaxis may be life-threatening and early intervention may improve outcomes.

Simple ostectomy to address quadriceps impingement caused by distal femoral malunion in four dogs

Four dogs were evaluated for chronic pelvic limb lameness. Radiographs revealed distal femoral malunion with caudo-proximal displacement, resulting in impingement of the quadriceps from the distal aspect of the proximal femoral segment. All dogs presented with femoral shortening and increased femoral procurvatum when compared with the normal contralateral femur. There was minimal angular or rotational misalignment. Treatment consisted of ostectomy of the fracture segment that was causing quadriceps impingement, with debridement of proliferative fracture callus proximal to the trochlear groove in all dogs. No attempt was made to address sagittal plane deformities. Long-term orthopaedic examination with objective gait analysis in three dogs revealed minimal to no lameness in two and mild residual lameness in one dog. Long-term radiographic analysis revealed fracture-site remodelling with an increase in femoral length and a return of near-normal femoral procurvatum in all dogs. Owner-assessed long-term outcome was excellent in all dogs.

Liver disease knowledge and acceptability of non-invasive liver fibrosis assessment among people who inject drugs in the drug and alcohol setting: The LiveRLife Study

BACKGROUND

The aim of this study was to assess factors associated with baseline knowledge of HCV and liver disease, acceptability of transient elastography (TE) assessment (FibroScan(®)), and willingness and intent to receive HCV treatment among persons with a history of injection drug use participating in a liver health promotion campaign.

METHODS

The LiveRLife campaign involved three phases: (1) campaign resource development; (2) campaign resource testing; and (3) campaign implementation. Participants were enrolled in an observational cohort study with recruitment at four clinics - one primary health care facility, two OST clinics, and one medically supervised injecting centre - in Australia between May and October 2014. Participants received educational material, nurse clinical assessment, TE assessment, dried blood spot testing, and completed a knowledge survey.

RESULTS

Of 253 participants (mean age 43 years), 68% were male, 71% had injected in the past month, and 75% self-reported as HCV positive. Median knowledge score was 16/23. In adjusted analysis, less than daily injection (AOR 5.01; 95% CI, 2.64-9.51) and no daily injection in the past month (AOR 3.54; 95% CI, 1.80-6.94) were associated with high knowledge (≥16). TE was the most preferred method both pre- (66%) and post-TE (89%) compared to liver biopsy and blood sample. Eighty-eight percent were 'definitely willing' or 'somewhat willing' to receive HCV treatment, and 56% intended to start treatment in the next 12 months. Approximately 68% had no/mild fibrosis (F0/F1, ≥2.5 to ≤7.4kPa), 13% moderate fibrosis (F2, ≥7.5 to ≤9.4kPa), 10% severe fibrosis (F3, ≥9.5 to ≤12.4kPa), and 9% had cirrhosis (F4, ≥12.5kPa).

CONCLUSION

Liver disease and HCV knowledge was moderate. High acceptability of TE by PWID provides strong evidence for the inclusion of TE in HCV-related care, and could help to prioritise HCV treatment for those at greatest risk of liver disease progression.

Divorcing the Late Upper Palaeolithic demographic histories of mtDNA haplogroups M1 and U6 in Africa

Background

A Southwest Asian origin and dispersal to North Africa in the Early Upper Palaeolithic era has been inferred in previous studies for mtDNA haplogroups M1 and U6. Both haplogroups have been proposed to show similar geographic patterns and shared demographic histories.

Results

We report here 24 M1 and 33 U6 new complete mtDNA sequences that allow us to refine the existing phylogeny of these haplogroups. The resulting phylogenetic information was used to genotype a further 131 M1 and 91 U6 samples to determine the geographic spread of their sub-clades. No southwest Asian specific clades for M1 or U6 were discovered. U6 and M1 frequencies in North Africa, the Middle East and Europe do not follow similar patterns, and their sub-clade divisions do not appear to be compatible with their shared history reaching back to the Early Upper Palaeolithic. The Bayesian Skyline Plots testify to non-overlapping phases of expansion, and the haplogroups’ phylogenies suggest that there are U6 sub-clades that expanded earlier than those in M1. Some M1 and U6 sub-clades could be linked with certain events. For example, U6a1 and M1b, with their coalescent ages of ~20,000–22,000 years ago and earliest inferred expansion in northwest Africa, could coincide with the flourishing of the Iberomaurusian industry, whilst U6b and M1b1 appeared at the time of the Capsian culture.

Conclusions

Our high-resolution phylogenetic dissection of both haplogroups and coalescent time assessments suggest that the extant main branching pattern of both haplogroups arose and diversified in the mid-later Upper Palaeolithic, with some sub-clades concomitantly with the expansion of the Iberomaurusian industry. Carriers of these maternal lineages have been later absorbed into and diversified further during the spread of Afro-Asiatic languages in North and East Africa.

Variation of respiratory resistance suggests optimization of airway caliber

Physiologically optimized processes, such as respiration, walking, and cardiac function, usually show a range of variability about the optimized value. Airway resistance has, in the past, been noted as variable, and this variability has been connected to pulmonary disease (e.g., asthma). A hypothesis was presented many years ago that postulated airway resistance as an optimized parameter in healthy individuals, and we have noticed that respiratory measurements made with the airflow perturbation device (APD) tend to be variable in nature. It was posited that this variability indicates that respiratory resistance is optimized similarly to other physiological processes. Fifty subjects with a wide range of demographics volunteered to have 100 measurements made of their respiratory resistances. Resistances were separated into inhalation and exhalation phases. These were plotted and shown to have frequency distributions that were consistent with expectations for an optimized process. The frequency distributions were not quite symmetrical, being skewed slightly toward upper resistances. Comparison between subject data and data from a mechanical respiratory analog showed that subject resistance variation is overwhelmingly from the respiratory system and not from the APD.

Branded food references in children's magazines: 'advertisements' are the tip of the iceberg

OBJECTIVE

While children's magazines 'blur the lines' between editorial content and advertising, this medium has escaped the calls for government restrictions that are currently associated with food advertisements aired during children's television programming. The aim of this study was to address significant gaps in the evidence base in relation to commercial food messages in children's magazines by systematically investigating the nature and extent of food advertising and promotions over a 12-month period.

METHOD

All issues of Australian children's magazines published in the calendar year 2009 were examined for references to foods or beverages.

RESULTS

Approximately 16% of the 1678 food references identified were portrayals of branded food products (or food brands). However, only 83 of these 269 were clearly identified as advertisements. Of these 269 branded food references, 86% were for non-core (broadly, less healthy) foods, including all but seven of the advertisements.

CONCLUSIONS

It appears that recent reductions in televised promotions for non-core foods, and industry initiatives to reduce the targeting of children, have not carried through to magazine advertising. This study adds to the evidence base that the marketing of unhealthy food to children is widespread, and often covert, and supports public health calls for the strengthening of advertising regulation.

Sodium MRI and the assessment of irreversible tissue damage during hyper-acute stroke

Sodium MRI (sMRI) has undergone a tremendous amount of technical development during the last two decades that makes it a suitable tool for the study of human pathology in the acute setting within the constraints of a clinical environment. The salient role of the sodium ion during impaired ATP production during the course of brain ischemia makes sMRI an ideal tool for the study of ischemic tissue viability during stroke. In this paper, the current limitations of conventional MRI for the determination of tissue viability during evolving brain ischemia are discussed. This discussion is followed by a summary of the known findings about the dynamics of tissue sodium changes during brain ischemia. A mechanistic model for the explanation of these findings is presented together with the technical requirements for its investigation using clinical MRI scanners. An illustration of the salient features of the technique is also presented using a nonhuman primate model of reversible middle cerebral artery occlusion.

Asthma and ageing: an end user's perspective--the perception and problems with the management of asthma in the elderly

Despite the high prevalence of asthma in the elderly, its development, diagnosis, and treatment are under-researched. This paper provides a comprehensive review of the current state of knowledge in relation to management of asthma in the elderly - focusing on barriers to diagnosis and treatment and the central role of self-management. Asthma prevalence increases with age, as does the risk of dying from asthma, and with the ageing of the population and increasing life expectancy, the prevalence of (diagnosed and undiagnosed) asthma in older adults is expected to increase drastically, placing an increasing burden on sufferers, the community and health budgets. Asthma sufferers are more likely to be psychologically distressed and at a higher risk of anxiety and depression, more likely to experience a sense of lack of control over their health and to have lower self-reported quality of life. Asthma is under-diagnosed, and under-treated, in the elderly, further exacerbating these negative consequences. The review concludes, among other things, that there is a need to better understand the development and impact of asthma in the elderly, to increase community awareness of asthma in the elderly, to improve both 'medical management' and 'self-management' in this population and to develop more effective tools for diagnosis and treatment of asthma in the elderly. The paper concludes with key recommendations for future research and practice in this area.

Prevalence and nature of anaemia in a prospective, population-based sample of people with diabetes: Teesside anaemia in diabetes (TAD) study

AIMS

Anaemia occurs in 25% of people attending hospital diabetes clinics, but this may not be representative of all people with diabetes. We aimed to determine the prevalence of anaemia in a prospective population-based sample stratified by estimated glomerular filtration rate (eGFR) using the 4-point Modification of Diet in Renal Disease (MDRD) formula.

METHODS

All 7331 patients on our district register were stratified by eGFR. Seven hundred and thirty were approached by letter on two occasions. Two hundred and thirty-four (32%) returned questionnaires and blood samples. Responders (R), non-responders (NR) and the whole cohort (C) were similar: mean +/- sd age R 61.7 +/- 12.7 years; NR 61.3 +/- 15.1 years; C 61.8 +/- 14.2 years; diabetes duration R 8.8 +/- 8.6 years; NR 8.2 +/- 7.9 years; C 7.5 +/- 7.8 years, Type 1 diabetes R 10.1%, NR 10.8%, C 9.4%. Anaemia was defined using World Health Organization criteria: haemoglobin < 13 g/dl for men, < 12 g/dl for women.

RESULTS

Previously undiagnosed anaemia was present in 15% of the whole group, 36% with eGFR < 60 ml/min per 1.73 m(2) and 9% of those with eGFR > 60 ml/min per 1.73 m(2). Anaemia was as a result of erythropoietin deficiency in 34%, abnormal haematinics in 40% and was unexplained in 26% of patients. Five per cent of the patients had anaemia below the treatment threshold of 11 g/dl.

CONCLUSIONS

The prevalence of unrecognized anaemia in population-based cohorts is lower than that in hospital-based studies. Current clinical surveillance in the UK is failing to detect anaemia in stage 3-5 chronic kidney disease (eGFR < 60 ml/min per 1.73 m(2)) and current guidelines will not detect 9% of diabetic patients with anaemia and an eGFR > 60 ml/min per 1.73 m(2).

Guidelines for the development of social marketing programmes for sun protection among adolescents and young adults

OBJECTIVES

To formulate 'best practice' guidelines for social marketing programmes for adolescents' and young adults' sun protection.

STUDY DESIGN

A Delphi consensus process.

METHODS

Eleven experts in sun protection and social marketing participated in a Delphi consensus process, where they were asked to provide up to 10 key points, based on their knowledge and practical experience, which they felt were most important in developing social marketing interventions for the primary prevention of skin cancer among adolescents and young adults. After reaching consensus, the evidence base for each guideline was determined and graded via the Scottish Intercollegiate Guideline Network grading system. Participants were then asked to indicate how strongly they rated the finalized 15 recommendations based on all aspects relating to their knowledge and practical opinion, as well as the research evidence, on a visual analogue scale.

RESULTS

The resultant 15 guidelines offer general principles for sun protection interventions utilizing a social marketing approach.

CONCLUSIONS

This method of guideline development brought the expertise of practitioners to the forefront of guideline development, whilst still utilizing established methods of evidence confirmation. It thus offers a useful method for guideline development in a public health context.

Messages in alcohol advertising targeted to youth

OBJECTIVE

To assess young people's perceived messages in three ads for a vodka-based, pre-mixed alcohol beverage, and to assess the extent to which the ads appeared to be consistent with the industry's voluntary code.

METHOD

Members of two convenience samples of young people (15-16 and 19-21 years) were each exposed to one of three advertisements. Respondents completed a post exposure questionnaire based on standard advertising copy testing procedures.

RESULTS

The most frequently nominated open-ended responses to 'the main message(s) of the ad' related to the product delivering mood effects: both removal of negative emotions (e.g. 'stress reduction'), as well as inducing positive states such as feeling 'carefree' and gaining 'increased enjoyment'. Consumption of the product was perceived to offer 'self-confidence', 'sexual/relationship success' and 'social success'. Fewer respondents nominated tangible product characteristics, the main one being 'easy to drink'. One in four of the 15-16 year olds saw the ads as aimed at 'people my age', while almost half of the 19-21 year olds saw the ads as aimed at 'people younger or much younger than me'.

DISCUSSION

These results appear to contravene the Alcoholic Beverages Advertising Code (ABAC) by suggesting that the consumption of alcohol beverages: (i) contributes to social and sexual success; and (ii) contributes to a significant change in mood (stress reduction/relaxation).

IMPLICATIONS

Incidental observation of alcohol ads suggests that contravention of the code is more widespread than the number of alcohol advertising complaints would indicate. All 11 such complaints lodged with the Advertising Standards Board between May 1998 and April 1999 were dismissed. Evidence such as that gathered in this study might improve the chances of complaints being upheld.

Push-pull analysis of photonic Doppler velocimetry measurements

A robust analysis method is presented for multiple-phase heterodyne velocimetry measurements. By combining information from three phase-shifted signals, it is possible to eliminate coherent intensity variations and incoherent light from the measurement. The three data signals are reduced to a pair of quadrature signals, allowing unambiguous calculation of target displacement. The analysis relies on a minimum number of adjustable parameters, and these parameters can be precisely determined from simple interferometer characterization.

Gaining insight into the what, why and where of complementary and alternative medicine use by cancer patients and survivors

The aim of this study was to gain a greater understanding of complementary and alternative medicine (CAM) use among cancer patients and survivors. Specific objectives included types used and timing, motivations for use and benefits received, sources of information on CAM and communication with doctors. Semi-structured in-depth interviews were conducted with 19 patients and survivors (mean age = 57 years). Findings on frequency and type of CAM use were consistent with previous studies. Additionally, we found that the main expected benefit from using CAM was to boost the immune system, that participants could not readily explain the nature of the benefits they received, that CAM practitioners and books were the main sources of CAM information, and that the majority reported some discussion of CAM with a doctor. A greater range of questions needs to be asked of cancer patients in future quantitative studies. Reasons for commencing and stopping use of CAM and the quality of the CAM information source will be imperative to uncover, especially as the Internet is increasing in importance as a source for health information.

Interprofessional education in undergraduate healthcare programmes: the reaction of student dietitians

BACKGROUND

Interprofessional education (IPE) is a novel teaching and learning initiative where students of more than one health profession learn interactively together. However, despite its potential for improving interprofessional relationships, there is little information regarding the participation of student dietitians in IPE. The aim of this paper was to consider the reaction of student dietitians to an IPE course in order to stimulate debate between dietitians regarding the issues relating to IPE.

METHODS

Student dietitians participated in an IPE course consisting of seven sessions on communication and ethics in health care together with students of medicine and nursing. Student dietitians completed an evaluation questionnaire following each session that surveyed their reaction to the session using both a Likert scale and free-text comments.

RESULTS

Twenty-six student dietitians completed the IPE course. All sessions were rated positively for interest value (P < or = 0.14), learning experience (P < or = 0.036) and value for clinical practice (P < or = 0.05). The limited number of free-text comments indicated some positive experiences regarding interprofessional learning, teaching content and teaching strategy.

CONCLUSIONS

This is one of very few evaluations to describe the reaction of student dietitians to IPE. Student dietitians had largely positive reactions to the IPE course. Further research is required to evaluate whether these positive reactions were a direct consequence of the inclusion of students from other health professions and whether these translate into positive effects on learning, behaviour and results. The opportunities for the dietetic profession posed by students' involvement in IPE are discussed.

Dietary acid-base balance and intake of bone-related nutrients in Cambridge teenagers

OBJECTIVES

To evaluate the diet of 16-18-y-old boys and girls with particular reference to intakes of nutrients believed to affect bone health and dietary acid-base balance.

DESIGN

A 7-day food diary was completed between the months of October and December.

SETTING

Cambridge, UK.

SUBJECTS

A total of 111 boys and 101 girls aged 16-18 y who were recruited into the Cambridge Bone Studies.

MAIN OUTCOME MEASURES

Mean daily intakes of foods and selected nutrients (protein, calcium, phosphorus, magnesium, potassium, vitamins C and K) were calculated. Two estimates of acid-base balance were calculated from the diet using the formulae of Remer (net acid excretion, estimated indirectly; NAE(ind)) and Frassetto (protein/potassium ratio).

RESULTS

Mean calcium and phosphorus intakes were above the UK Reference Nutrient intake (RNI). In all, 39% of the boys and 36% of the girls had vitamin K intakes lower than 1 microg/kg body weight/day. Calcium intake was positively correlated with all other nutrients except vitamins C and K. Boys had a significantly higher estimated net acid excretion (NAE(ind)) than girls (P<0.001). Although a strong correlation (r=0.76, P<0.001) was found between the two methods, at higher acid levels a divergence was observed. A significant positive correlation was found between NAE(ind) and the weight consumed per day of milk, cheese, meat and cereal foods and a negative correlation was found with the weight of potatoes and fruit. Diet composition is such that a lower NAE(ind) is accompanied by a lower calcium intake.

CONCLUSIONS

The interpretation of the effects of calcium and other nutrients on bone cannot be considered in isolation from the other components of the diet. These results challenge some of the accepted perceptions about what constitutes an optimal diet for the promotion of bone health in adolescents.

Restraining acute infarct expansion decreases collagenase activity in borderzone myocardium

BACKGROUND

After acute myocardial infarction, regional myocardial wall strains and stresses change and a complex cellular and biochemical response is initiated to remodel the ventricle. This study tests the hypothesis that changes in regional ventricular wall strains affect regional collagen accumulation and collagenase activity.

METHODS

Fourteen sheep had acute anteroapical infarction that progressively expands into left ventricular aneurysm within 8 weeks. In 7 sheep, infarct expansion was restrained by prior placement of mesh over the area at risk. Fourteen days after infarction, and after hemodynamic and echocardiographic measurements, animals were euthanized for histology, measurements of hydroxyproline, matrix metalloproteinase-1 (MMP-1 or collagenase) and MMP-2 (gelatinase) activity, as well as collagen type I and III in infarcted, borderzone, and remote myocardium.

RESULTS

Restraining infarct expansion does not change collagen content or MMP-1 or MMP-2 activity in the infarct, but significantly increases the ratio of collagen I/III. In borderzone and remote myocardium infarct, restraint significantly increases collagen content and significantly reduces MMP-1 activity. MMP-2 activity is reduced (p = 0.059) in borderzone myocardium only. Between groups, the ratio of type I/III fibrillar collagen does not change in borderzone myocardium.

CONCLUSIONS

Fourteen days after acute myocardial infarction, restraining infarct expansion increases collagen accumulation in borderzone and remote myocardium, which may prevent expansion of hypocontractile, fully perfused "remodeling myocardium" adjacent to the infarct. This study demonstrates that changes in regional myocardial wall strain alter the cellular and biochemical processes involved in postinfarction ventricular remodeling.

Early visual changes in reflected light on non-stained brain sections after focal ischemia mirror the area of ischemic damage

There is no reliable, simple method for delineation of ischemic regions at early time points after ischemia. We propose that at early times after stroke, ischemic regions can be visualized as a subtle change in reflected light directly in thaw-mounted, dried 20 microm brain sections. In 15 male Sprague-Dawley rats, anesthetized with isoflurane, middle cerebral artery transection and permanent bilateral common carotid artery occlusion was performed and brains were processed in five different ways. Areas of reflective change (RC) on non-stained sections were compared with areas on the adjacent sections delineated by microtubule associated protein 2 (MAP2) antibody, a reliable marker for early post-stroke, in five rats each at 1, 3, and 6 h after focal cerebral ischemia. A statistically significant correlation between ischemic areas (IA) measured on non-stained brain sections (IA(RC)) and adjacent sections immunostained (IM) with MAP2 Ab (IA(IM)) (IA(RC)=0.05+0.88.IA(IM); R2=0.8; n=15; P<0.01) and a small mean difference +/-2 S.D. (-0.9+/-6.0%) indicated that the area measured on non-stained sections reflects the IA measured on MAP2 -IM sections. At 1 and 3 h after ischemia, the ratio between ischemic regions measured on the non-stained sections and on the adjacent sections immunostained with MAP2 Ab were not different from 100% (97.6+/-1.7%, 100.9+/-6.0%). At 6 h post-stroke, the IA measured on the non-stained sections was larger than on the IM sections (109.8+/-2.7%, P<0.01, compared to 100% ratio). Our study demonstrated that this quick and simple method for detection of damaged brain permitted the use of brain tissue for other assays and could be very useful for neuroprotective evaluation and for directed micro-sampling of brain tissue at early times after ischemia.

HOPE for patients with Type 2 diabetes: an application of the findings of the MICRO-HOPE substudy in a British hospital diabetes clinic

AIMS

The MICRO-HOPE substudy demonstrated that when ramipril treatment was added to people with Type 2 diabetes and additional cardiovascular risk factors cardiovascular events were reduced by 25% in 4.5 years. We wished to determine the proportion of people with Type 2 diabetes and additional cardiovascular risk factors registered with a hospital diabetes service.

METHODS

Non-proteinuric people (n = 1370) with Type 2 diabetes identified on our diabetes register were subject to analysis. Anticipated reductions in cardiovascular events due to ramipril treatment were based on reductions observed in the MICRO-HOPE substudy.

RESULTS

Non-proteinuric people (n = 1075 (78%)) with Type 2 diabetes had at least one additional cardiovascular risk factor. Twenty-nine percent were already taking an angiotensin-converting enzyme inhibitor. The remaining 764 patients were similar to ramipril-treated participants in the MICRO-HOPE substudy. Treatment with ramipril for 4.5 years would be anticipated to reduce cardiovascular deaths by 26, revascularization procedures by 19 and admissions for myocardial infarction and stroke by 18 and 26, respectively.

CONCLUSIONS

Of non-proteinuric people with Type 2 diabetes, 78% have additional cardiovascular risk factors. Only a small proportion currently receive treatment with an angiotensin-converting enzyme inhibitor. The incidence of cardiovascular events could be reduced if more patients were treated with ramipril and other cardiovascular risk factors were addressed.

Vbeta spectratype analysis reveals heterogeneity of CD4+ T-cell responses to minor histocompatibility antigens involved in graft-versus-host disease: correlations with epithelial tissue infiltrate

Lethal graft-versus-host disease (GVHD) can be induced after hematopoietic stem cell transplantation between major histocompatibility complex-matched murine strains expressing multiple minor histocompatibility antigen (miHA) differences. In the C57BL/6By (B6)-->C.B10-H2b/LiMcdJ (BALB.B) irradiation model, both CD4+ and CD8+ donor T cells can mediate lethal GVHD, whereas in the B6-->CXB-2/By (CXBE) model, in which the recipient expresses a subset of BALB.B miHA, only the CD8+ T cells are lethal. Phenotypic analysis of CD4+ T cells collected from the thoracic duct lymphocyte pool of recipient mice had indicated expansion of the donor T-cell receptor Vbeta6-9 families in BALB.B recipients, and only Vbeta7 and Vbeta9 populations in CXBE mice. CDR3-size spectratyping, used to further analyze these responses, revealed overlapping oligoclonal expansion of Vbeta4, Vbeta6-10, and Vbeta12-14 families in both BALB.B and CXBE recipients injected with host-presensitized B6 T cells. In addition, the B6-->BALB.B CD4+ T-cell response appeared to involve the recognition of unique BALB.B-specific miHA, indicated by additional skewing of Vbeta2 and Vbeta11 families. On the other hand, the B6-->CXBE strain combination exhibited unique skewing of the Vbeta16 and Vbeta18 families. Immunohistochemical staining of lingual epithelial sections from BALB.B recipients of naive B6 CD4+ T cells correlated with the involvement of several of the spectratype-skewed Vbeta families in GVHD lesions. Furthermore, magnetic cell separation techniques were used to positively select the spectratype-skewed Vbeta families from the donor B6 CD4+ T cells; the former were found to have significant GVHD potential upon transplantation into lethally irradiated BALB.B recipients. In contrast, mice that received transplants from the unskewed Vbeta families all survived with minimal symptoms of GVHD. Taken together, these results demonstrate that the expansion of particular Vbeta families, as identified by spectratype analysis, correlates with the induction and pathogenesis of lethal GVHD.

Interaction between angiotensin II and Smad proteins in fibroblasts in failing heart and in vitro

Angiotensin II (angiotensin) and transforming growth factor (TGF)-beta(1) play an important role in cardiac fibrosis. We examined Smad proteins in 8-wk post-myocardial infarction (MI) rat hearts. AT(1) blockade (losartan) attenuated the activation of TGF-beta(1) in target tissues. Losartan administration (8 wk, 15 mg. kg(-1). day(-1)) normalized total Smad 2 overexpression in infarct scar and remnant heart tissue and normalized Smad 4 in infarct scar. Phosphorylated Smad 2 (P-Smad 2) staining decreased in cytosol from failing heart vs. the control, which was normalized by losartan, suggesting augmented P-Smad 2 movement into nuclei in untreated failing hearts. Using adult primary rat fibroblasts treated with angiotensin (10(-6) M), we noted rapid translocation (15 min) of P-Smad 2 into the nuclei from the cytosol. Nuclear P-Smad 2 protein level increased with angiotensin treatment, which was blocked by losartan. We conclude that angiotensin may influence total Smad 2 and 4 expression in post-MI heart failure and that angiotensin treatment is associated with rapid P-Smad 2 nuclear translocation in isolated fibroblasts. This study suggests that cross talk between angiotensin and Smad signaling is associated with fibrotic events in post-MI hearts.

Should intravenous tocolysis be considered beyond 34 weeks' gestation?

OBJECTIVE

Our purpose was to assess the incidence of respiratory distress syndrome in nonindigent women with uncomplicated preterm labor between 34 and 36 weeks' gestation.

STUDY DESIGN

All women seen between June 1, 1992, and April 15, 1999, with uncomplicated preterm labor and intact membranes and delivering between 34 and 36 weeks' gestation were analyzed. Rates of respiratory distress syndrome after delivery were calculated. A chi(2) analysis was performed, and a P value of <.05 was considered statistically significant.

RESULTS

Respiratory distress syndrome was noted in 8 (17.4%) of 46 infants delivered at 34 weeks' gestation, in comparison with 5 (6.3%) of 80 infants and 7 (4.2%) of 165 infants delivered at 35 and 36 weeks' gestation, respectively (P =.008). The rate of respiratory distress syndrome after delivery at 34 weeks was significantly higher than at 35 weeks (P =.048).

CONCLUSION

The rate of respiratory distress syndrome after delivery at 34 weeks is significantly higher than at either 35 or 36 weeks' gestation in our population.

Directed sampling for electrolyte analysis and water content of micro-punch samples shows large differences between normal and ischemic rat brain cortex

Changes in sodium, potassium, and water content in brain tissue are important in the progression of pathology that follows ischemic stroke. Determining these parameters regionally in rodent models of experimental ischemia has been limited because typical tissue weights of more than 35 mg are too large. Identifying ischemic tissue to direct tissue sampling towards ischemic cortex is also represents a difficult generally unresolved area. We suggest that larger differences between normal and ischemic cortex of sodium, potassium, and water content than previously observed can be obtained from directed sampling of 2-mg brain tissue in a model of focal cerebral ischemia. In five rats, the middle cerebral artery and both common carotid arteries were occluded for 4.9+/-0.13 h (mean+/-SEM). Punch-sampling of 1-mm diameter tissue cores for water content (H(2)O%) by the wet-dry method, and [Na(+)] and [K(+)] by flame photometry, was guided by the observation of a subtle change in the surface reflectivity of ischemic cortex of quickly dried, 20-microm frozen brain sections, that was confirmed by MAP2 immunohistochemistry. The ratio of the lesion areas as determined by the reflective change and MAP2 immunoreactivity was 0.96+/-0.03 (n=5). In ischemic cortex H(2)O% was 79.9%+/-0.8%, [Na(+)] was 550+/-25 mEq/kg dry-weight, and [K(+)] 94.2+/-19.2 mEq/kg dry-weight (n=5), all significantly different from the values in border zone cortex, and in cortex contralateral to ischemic cortex and border zone (for all samples n=60, mean wet weight 2.037+/-0.046 mg). Differences between ischemic and normal cortex were 5.4+/-1.1%, 317+/-21 mEq/kg dry-weight, -304+/-27 mEq/kg dry-weight (n=5) for H(2)O%, [Na(+)], and [K(+)]. These differences between ischemic and normal cortex are 1.4-2.5, 1-3.11, and 1.4-3.5 times greater, respectively, than previous results obtained using samples weighing 35 mg or more. These results extend the association of sodium and potassium with ischemic brain edema in the rodent model, and show that these classical measurements can keep pace with the regionality of histochemical and morphological methods.

Brain tissue sodium is a ticking clock telling time after arterial occlusion in rat focal cerebral ischemia

BACKGROUND AND PURPOSE

Many patients with acute stroke are excluded from receiving thrombolysis agents within the necessary time limit (3 or 6 hours from stroke onset) because they or their family members are unable provide the time of stroke onset. Brain tissue sodium concentration ([Na(+)]) increases gradually and incessantly during the initial hours of experimental focal cerebral ischemia but only in severely damaged brain regions. We propose that this steady increase in [Na(+)] can be used to estimate the time after arterial occlusion in the rat middle cerebral artery occlusion model of ischemic stroke.

METHODS

Sixteen anesthetized Sprague-Dawley rats underwent permanent middle cerebral artery occlusion combined with bilateral common artery occlusion. After 100 to 450 minutes, diffusion-weighted MRI was used to generate apparent diffusion coefficient (ADC) maps, cerebral blood flow (CBF) was determined with (14)C-iodoantipyrine (in a subset of 7 animals), and the brain was frozen. Autoradiographic CBF sections and punch samples for Na(+) analysis were obtained from the brain at the same level of the MR image. Severely at risk regions were identified with an ADC of <520 microm(2)/s and, in the subset, with both ADC of <520 microm(2)/s and CBF of <40 mL. 100 g(-1). min(-1).

RESULTS

Both CBF and the ADC dropped quickly and remained stable in the initial hours after ischemic onset. Linear regression revealed strong linearity between [Na(+)] and time after onset, with a slope of 0.95 or 1.00 (mEq/kg DW)/min, with both ADC and ADC-plus-CBF criteria, respectively. The 95% CIs at 180 and 360 minutes were between 41 and 52 minutes.

CONCLUSIONS

The time after ischemic onset can be estimated with this 2-step process. First, ADC and CBF are used to identify severely endangered regions. Second, the [Na(+)] in these regions is used to estimate time after onset. The favorable 95% CIs at the time limits for thrombolytic therapy and the availability of measurements of ADC, CBF, and [Na(+)] in humans through the use of MRI suggest that this time-estimation scheme could be used to assess the appropriateness of thrombolysis for patients who do not know when the stroke occurred.

High glucose increases growth and collagen synthesis in cultured human tubulointerstitial cells

AIMS

Altered proximal tubular cell growth and interstitial fibrosis are features of diabetic nephropathy and correlate with disease progression. These observations are poorly understood, although it has been suggested that they are secondary to glomerular disease. The primary aim of this study was to assess the direct effects of high extracellular glucose concentrations on the human tubulointerstitium.

METHODS

Primary cultures of human proximal tubule cells (PTCs) and cortical fibroblasts (CFs) were grown for 6 days in media containing either 6.1 mmol/l or 25 mmol/l glucose. Cell proliferation, thymidine uptake (a marker of DNA synthesis), protein content and collagen synthesis were measured.

RESULTS

In PTCs, exposure to high glucose was associated with a 410+/-108% increase in cell numbers (P<0.001); 101+/-24% increase in thymidine uptake per cell (P<0.01) and a 39+/-6% decrease in protein content per cell (P<0.05). Collagen synthesis was increased by 37+/-11% (P<0.05). In CFs, exposure to high glucose was associated with an 80+/-25% increase in cell numbers (P<0.05); 137+/-50% increase in thymidine uptake per cell (P<0.001), with protein content per cell unchanged. Collagen synthesis increased by 37+/-13%; however, the difference was not significant (P = 0.07). There were no differences between control cells exposed to 6.1 mmol/l glucose or an osmotic control (6.1 mmol/l D-glucose +18.9mmol/l L-glucose).

CONCLUSIONS

Exposure of human PTCs and CFs to high extracellular glucose concentrations results directly in altered cell growth and collagen synthesis that is independent of haemodynamic, glomerular or vascular pathology.

Intermittent high glucose enhances cell growth and collagen synthesis in cultured human tubulointerstitial cells

AIMS/HYPOTHESIS

We investigated the effects of constant and intermittently increased glucose concentrations on human proximal tubule cells and cortical fibroblasts in primary culture.

METHODS

Cells were grown to confluence and then exposed for 4 days to 6.1 mmol/l D-glucose (normal), 25 mmol/l D-glucose (high), or 6.1 mmol/l alternating with 25 mmol/l D-glucose on a daily basis.

RESULTS

In proximal tubular cells, exposure to high glucose caused an 11 % increase in thymidine uptake (p < 0.05), a 230 % increase in secretion of transforming growth factor beta 1 (TGF-beta1; p < 0.05) and a 393 % increase in platelet derived growth factor. Intermittent exposure to high glucose caused thymidine uptake to further increase by 42 % (p < 0.01) and TGF-beta1 secretion by 352 % (p < 0.01) but no additional increase in platelet-derived growth factor secretion was observed. Cellular protein content increased by 27 % (p < 0.05) and collagen synthesis by 29 % (p < 0.05), changes that were not observed in cells constantly exposed to high glucose. In cortical fibroblasts constant exposure to high glucose caused a 35 % increase in thymidine uptake (p < 0.01). Intermittently high glucose increased thymidine incorporation a further 58 % (p < 0.001), collagen synthesis by 65 % (p < 0.01) and insulin-like growth factor binding protein 3 secretion by 216 % (p < 0.01).

CONCLUSION/INTERPRETATION

In cultured human tubulointerstitial cells, increased glucose concentrations change cell growth, collagen synthesis and cytokine secretion. These effects are enhanced following intermittent exposure to high glucose, indicating that short lived excursions in glycaemic control have important pathological effects on the human tubulointerstitium.

Bone mineralization and turnover in preterm infants at 8-12 years of age: the effect of early diet

Our previous studies raised two hypotheses: first that suboptimal early nutrition and second that human milk have enhancing effects on long-term bone mineralization. To test these hypotheses experimentally, we measured whole body and regional bone mineral content (BMC) and bone mineral density (BMD), using dual-energy X-ray absorptiometry and single-photon absorptiometry, and bone turnover at 8-12 years in 244 preterm children (128 boys) who participated in a prospective randomized study of diet during the neonatal period. Dietary randomizations studied were: banked human milk (BBM, n = 87) versus preterm formula (PTF, n = 96) as the sole diet or as a supplement to mother's expressed breast milk (EBM); PTF (n = 25) versus term formula (TF, n = 36) as sole diet. Ninety-five term children of the same age were also studied. First, preterm children were shorter and lighter than term children (height SD scores -0.49 (1.1) vs. +0.22 (0.9), weight SD scores -0.41 (1.2) vs. +0.38 (1.0)) and had significantly lower whole-body BMC than their peers; decrements were also evident at some regional sites. These differences disappeared after adjusting for bone area, body size, and pubertal status. Second, children previously randomized to BBM versus PTF or TF versus PTF showed no significant differences in anthropometry, BMC, BMD, or osteocalcin (OC). Third, there was no independent effect of the proportion of EBM on BMC, BMD, or OC and no interaction between randomized diet and the amount of EBM received. Fourth, plasma OC was significantly higher in preterm children than in term children (12.4 vs. 11.0 ng/ml, p < 0.005) and in preterm children who had received a low-nutrient (BBM/TF) as opposed to a high-nutrient diet (PTF) during the neonatal period (12. 9 vs. 11.9 ng/ml, p = 0.03). In conclusion, preterm children are shorter, lighter, and have lower bone mass than their peers at age 8-12 years. The lower BMC is, however, appropriate for the bone and body size achieved. Despite large differences in early mineral intake, early diet does not affect bone mass in preterm children, and fresh human milk has no specific effect. However, poor nutrition during the neonatal period may result in higher bone formation rates during childhood.

Cortical NOS inhibition raises the lower limit of cerebral blood flow-arterial pressure autoregulation

The maintenance of constant cerebral blood flow (CBF) as arterial blood pressure is reduced, commonly referred to as CBF-pressure autoregulation, is typically characterized by a plateau until the vasodilatory capacity is exhausted at the lower limit, after which flow falls linearly with pressure. We investigated the effect of cortical, as opposed to systemic, nitric oxide synthase (NOS) inhibition on the lower limit of CBF-pressure autoregulation. Forty-four Sprague-Dawley rats were anesthetized with halothane and N2O in O2. With a closed cranial window placed the previous day in a ventilated and physiologically stable preparation, we determined the CBF using laser-Doppler flowmetry. Animals with low reactivity to inhaled CO2 and suffused ADP or ACh were excluded. Five arterial pressures from 100 to 40 mmHg were obtained with controlled hemorrhagic hypotension under cortical suffusion with artificial cerebrospinal fluid (aCSF) and then again after suffusion for 35 (n = 5) and 105 min (n = 10) with aCSF, 10(-3) M Nomega-nitro-L-arginine (L-NNA; n = 12), or 10(-3) M Nomega-nitro-D-arginine (D-NNA; n = 5). An additional group (n = 7) was studied after a 105-min suffusion of L-NNA followed by a single blood withdrawal procedure. The lower limit of autoregulation was identified visually by four blinded reviewers as a change in the slope of the five-point plot of CBF vs. mean arterial blood pressure. The lower limit of 90 +/- 4.3 mmHg after 105 min of 1 mM L-NNA suffusion was increased compared with the value in the time-control group of 75 +/- 5.3 mmHg (P < 0.01; ANOVA) and the initial value of 67 +/- 3.7 mmHg (P < 0.001). The lower limit of 84 +/- 5.9 mmHg in seven animals with 105 min of suffusion of 1 mM L-NNA without previous blood withdrawal was significantly increased (P < 0.01) in comparison with 70 +/- 1.9 mmHg from those with just aCSF suffusion (n = 37). No changes in lower limit for the other agents or conditions, including 105 or 35 min of aCSF or 35 min of L-NNA suffusion, were detected. The lack of effect on the lower limit with D-NNA suffusion suggests an enzymatic mechanism, and the lengthy L-NNA exposure of 105 min, but not 35 min, suggests inhibition of a diffusionally distant NOS source that mediates autoregulation. Thus cortical suffusion of L-NNA raises the lower limit of autoregulation, strongly suggesting that nitric oxide is at least one of the vasodilators active during hypotension as arterial pressure is reduced from normal.

Physical performance: differences in men and women with and without low back pain

OBJECTIVE

To determine the extent to which there may be major differences in scores on a battery of physical performance tasks among men with nonspecific, mechanical low back pain (LBP), women with LBP, healthy men, and healthy women.

DESIGN

Case series survey.

SETTING

A referral-based orthopedic clinic.

PATIENTS

Thirty-three men and 46 women with LBP. Control Subjects: Twenty-one men and 25 women healthy controls.

INTERVENTION

Completion of six clinician-assessed physical performance tasks and self-report inventories.

MAIN OUTCOME MEASURE

Performance scores on distance walked in 5 minutes, 50-foot walk at fastest speed, repeated sit-to-stand, repeated trunk flexion, loaded forward reach, and the Sorensen fatigue tasks.

RESULTS

Discriminant function analysis revealed that the four groups of subjects performed the physical tasks significantly different in two major ways: (1) healthy control subjects outperformed LBP patients, irrespective of gender, on tasks involving trunk control, coordination, and stability while withstanding heavy or quickly changing loads on the spine; (2) men outperformed women, irrespective of patient or nonpatient status, on tasks involving anthropometric features of limb length. The findings provide guidance on reasonable performance expectations for men and women patients with LBP. Future studies of treatment effectiveness also will be able to assess physical performance change in terms of the intersection between standards set by the men and women healthy control subjects and those of men and women patients. However, whether a return to nonpatient status is an appropriate treatment goal is left to future research.

Vasopressin selectively increases 5-fluorouracil uptake by colorectal liver metastases following hepatic artery bolus infusion

BACKGROUND

Poor drug uptake secondary to the hypovascularity of colorectal liver metastases may partially explain their limited response to hepatic artery chemotherapy. Vasoconstrictors can increase tumor perfusion but their effect on drug uptake has not been well-characterized. The aim of this study was to determine whether vasopressin could selectively increase tumor uptake of 5-FU.

MATERIALS AND METHODS

A syngeneic rat model of colorectal liver metastases was used. Control group rats underwent a 60-s hepatic artery infusion of 14C-5-FU (30 mCi/150 microL). Treatment group rats had vasopressin (60 mIU/kg, dose determined in pilot study) added to the 14C-5-FU infusion. Mean systemic arterial pressure was minimally affected. Tumor:liver (T/L UR) and tumor center:periphery (C/P UR) 5-FU uptake ratios were determined using quantitative autoradiography techniques. Differences in tumor size (< or > 4 mm) and location (superficial vs deep) were accounted for. Statistical analysis was by repeated measures ANOVA (P = 0.01 significant).

RESULTS

A total of 161 tumors in 18 rats was analyzed. T/L URs were significantly higher in the treatment group compared to controls for tumors <4 mm (1.72 +/- 0.14 vs 0.70 +/- 0.16, P <0.001), tumors >4 mm (0.99 +/- 0.15 vs 0.45 +/- 0.16, P = 0.01), deep tumors (1.17 +/- 0.13 vs 0.68 +/- 0.15, P = 0.01), and superficial tumors (1.54 +/- 0. 15 vs 0.47 +/- 0.17, P <0.001). C/P URs did not differ significantly between the groups.

CONCLUSIONS

The results of this study show that vasopressin selectively enhances the uptake of 5-FU by colorectal liver metastases in a rat model of hepatic artery infusion. This may represent a promising strategy for improving tumor response rates and patient survival.

Abnormal regulation of cell membrane fluidity in diabetic nephropathy

An abnormality of the physical properties of the cell membrane may underlie the defect that unites the clinical and biochemical abnormalities found in subjects with diabetic nephropathy. The cell membrane is linked both structurally and functionally with the cytoskeleton. The fluorescence anisotropy, a measure of membrane fluidity, was studied at baseline and after modulation of cytoskeletal proteins by thiol group alkylation with N-ethylmaleimide (NEM). 1,6-diphenyl-1,3,5-hexatriene (DPH) was used to assess anisotropy in the deep hydrophobic regions of the lipid bilayer and trimethylammonium-diphenylhexatriene (TMA-DPH) was used to assess the superficial, relatively hydrophilic regions. We compared 17 subjects with insulin-dependent diabetes mellitus (IDDM) and nephropathy with 17 control subjects with IDDM and 24 non-diabetic control subjects. Median TMA-DPH anisotropy (0.271 (0.239-0.332) vs 0.269 (0.258-0.281) vs 0.275 (0.246-0.287)) and DPH anisotropy (0.221 (0.193-0.261) vs 0.227 (0.197-0.253) vs 0.226 (0.193-0.245)) were similar in erythrocytes from the three groups. However after alkylation of protein thiol groups with NEM clear differences emerged. In the control subjects with and without IDDM there was a significant fall in TMA-DPH anisotropy compared to the subjects with diabetic nephropathy in whom the addition of NEM had no effect (deltaTMA-DPH anisotropy -0.005 (-0.020 - +0.006) vs -0.005 (-0.011 - +0.016) vs +0.002 (-0.010 - +0.008) p < 0.001). This finding was confirmed when the deep regions of the lipid bilayer were assessed using DPH (deltaDPH anisotropy -0.017 (-0.029 - -0.007.) vs -0.015 (-0.029 - +0.001) vs + 0.003 (-0.021 - +0.018) p < 0.001). We conclude that cytoskeletal modulation of the physical properties of the cell membrane lipids by proteins is abnormal in subjects with diabetic nephropathy. Such an abnormality could explain some of the clinical and metabolic abnormalities found in this condition.

Inhibition of transforming growth factor alpha stimulation of human squamous cell carcinoma of the head and neck with anti-TGF-alpha antibodies and tyrphostin

BACKGROUND

Transforming growth factor alpha (TGF-alpha) and its receptor (EGF-R) may regulate normal and malignant epithelial cell growth by an autocrine mechanism. We investigated the role of TGF-alpha in regulating head and neck SCC tumor growth.

METHODS

TGF-alpha and EGF-R levels were measured in 7 SCC cell lines and 14 SCC biopsies by RIA, Scatchard, and Western analysis. TGF-alpha autocrine stimulation of DNA synthesis in SCC cell lines was assessed by incubation with TGF-alpha neutralizing antibodies and tyrphostin AG 1478, a selective and potent inhibitor of EGF-R kinase.

RESULTS

All SCC cell lines synthesized TGF-alpha and expressed elevated EGF-R levels compared to normal keratinocytes. Twelve of the 14 SCC biopsies contained TGF-alpha protein and 8 had specific EGF-R. Exogenous TGF-alpha or EGF significantly increased DNA synthesis in 4 of 5 SCC cell lines. TGF-alpha neutralizing antibodies or tyrphostin AG 1478 reduced DNA synthesis in the two SCC cell lines (FaDu and SCC9) tested.

CONCLUSIONS

These results indicate that SCC cell lines and tumors usually synthesize TGF-alpha, have elevated levels of EGF-R, and are mitogenically stimulated by a TGF-alpha autocrine system. Selective inhibition of the TGF-alpha system by EGF-R kinase inhibitors or TGF-alpha neutralizing antibodies may be useful strategies for treating SCC that overexpress TGF-alpha and its receptor.

Suitability of laser stimulated TLD arrays as patient dose monitors in high dose x-ray imaging

Skin entrance doses of patients undergoing interventional x-ray procedures are capable of causing skin damage and should be monitored routinely. Single TLD chips are not suitable because the location of maximum skin exposure cannot be predicted. Most photographic films are too sensitive at diagnostic x-ray energies for dosimetry, exhibit temporal changes in response, and require special packaging by the user. We have investigated the suitability of laser heated MgB4O7 TLDs in a polyimide binder in the range of 0.2-20 Gy. These are available in radioluscent arrays up to 30 x 30 cm for direct measurement of patient skin dose. Dose response was compared with a calibrated ion chamber dosimeter. Exposures were made at 60, 90, and 120 kVp, at low (fluoroscopy) and high (DSA) dose rates, and at different beam incidence angles. Longitudinal reproducibility and response to temperature changes during exposure were also checked. The dose response is linear below approximately 6 Gy where the slope starts to increase 2% per Gy. Errors were less than +/- 2% over a 0-80 degrees range of beam incidence angles; less than +/- 3% for both dose rate variations and kVp differences between 70 and 120 kVp. The response was unaffected by temperature changes between 20 and 37 degrees C. Reproducibility is current +/- 7%. MgB4O7 TLD arrays are suitable for patient dosimetry in high dose fluoroscopy procedures if appropriate calibrations are used. Uncertainty in skin dose measurement is less than 10%, which is substantially better than film dosimetry.

Thiol group modulation of sodium-lithium countertransport kinetics in diabetic nephropathy

Abnormal erythrocyte sodium-lithium countertransport (Na-Li CT) activity, traditionally measured at a single sodium concentration of 140 mmol.l-1 (V140), may represent an inherited risk marker for diabetic nephropathy. The membrane defect underlying this association is poorly understood, though modulation by key protein thiol groups appears to be important in essential hypertension. To improve understanding of this abnormality, Na-Li CT kinetics in untreated erythrocytes and after thiol group alkylation with N-ethylmaleimide were investigated in 18 subjects with diabetic nephropathy, 20 normoalbuminuric insulin-dependent diabetic (IDDM) subjects and 18 non-diabetic individuals. Using the traditional assay, V140 was similar in subjects with diabetic nephropathy compared to IDDM control subjects vs 0.311 (0.152-0.475) (0.247 (0.111-0.498) mmol Li.h-1.l erythrocytes-1). Kinetic parameters were abnormal in subjects with diabetic nephropathy compared with diabetic and non-diabetic control subjects with both Vmax (maximal Na-Li CT activity) (0.454 (0.257-0.963) vs 0.338 (0.183-0.972) vs 0.332 (0.213-0.603) mmol Li.h-1.l erythrocytes-1, p < 0.05), and Vmax/Km(So) ratio, reflecting ion association (6.03 (2.3-9.6) vs 4.73 (2.0-10.4) vs 4.48 (1.5-7.1), p < 0.01), significantly higher. N-ethylmaleimide decreased K(m)(So) and Vmax abolishing differences in Vmax/Km(So) ratio between groups (2.45 (1.18-4.21) vs 2.23 (0.96-4.3) vs 2.44 (1.4-3.7), but enhancing the differences in Vmax (0.186 (0.090-0.315) vs 0.120 (0.051-0.256) vs 0.128 (0.080-0.206) mmol Li.h-1.l erythrocytes-1, p < 0.0001). Of subjects with diabetic nephropathy, 78% were outside the 75th percentile of the non-diabetic control subjects when Vmax and Vmax/Km(So) ratio were combined, compared to 20% of the normoalbuminuric control subjects. We conclude that the traditional assay, V140, is poor at detecting individuals with diabetic nephropathy. Study of the kinetic parameters of the transporter, including thiol group modulation, suggests that increased ion association, Vmax/Km(So) ratio may represent the inherited defect and improves identification of subjects with diabetic nephropathy.

Perfusion to colorectal cancer liver metastases is not uniform and depends on tumor location and feeding vessel

Future effective therapies for hepatic metastases may depend on a better understanding of perfusion to these tumors. The purpose of this project was to define blood flow to colorectal cancer liver metastases using quantitative autoradiography (QAR). Liver tumors were established in F1 hybrids of WF x BN rats by intrasplenic injection of a DMH-induced rat colon adenocarcinoma. Rats underwent laparotomy 4-5 weeks later and [14C]iodoantipyrine (a radiotracer) was infused via the hepatic artery (HA) or portal vein (PV). Livers were harvested, frozen in liquid nitrogen, and sectioned at 20 microns through all tumors. QAR compared optical density of cross sections of tumors to surrounding normal liver tissue. Tumor:liver perfusion ratios (T/L PR) and tumor center:tumor periphery perfusion ratios (C/P PR) were calculated. All groups were analyzed with regard to tumor location and size. Seventy-seven tumors in 6 rats in the HA infusion group were analyzed; 74 tumors in 8 rats in the PV group were analyzed. Statistical analysis was by repeated measures analysis of variance. Mean HA T/L PR = 0.97 +/- 0.13, mean PV T/L PR = 0.25 +/- 0.11. Mean HA T/L PR for deep tumors was 1.38 +/- 0.17 and for superficial tumors was 0.57 +/- 0.15 (P < 0.01). Mean HA T/L PR for small tumors was 1.09 +/- 0.12 and for large tumors was 0.86 +/- 0.21 (P = 0.27). Mean PV T/L PR for deep tumors was 0.27 +/- 0.14 and for superficial tumors was 0.24 +/- 0.15 (P = 0.71). Mean PV T/L PR for small tumors was 0.31 +/- 0.15 and for large tumors was 0.20 +/- 0.14 (P = 0.54). Mean HA C/P PR = 1.15 +/- 0.15, mean PV C/P PR = 0.81 +/- 0.14 (P = 0.06). Mean HA C/P PR for small tumors was 1.37 +/- 0.16 and for large tumors was 0.92 +/- 0.17 (P = 0.01). Mean PV C/P PR for small tumors was 0.78 +/- 0.18 and for large tumors was 0.72 +/- 0.13 (P = 0.71). HA perfusion of tumors is significantly higher than PV perfusion compared to surrounding normal liver tissue. HA perfusion varies significantly depending on tumor location. There was a trend toward HA perfusion to the tumor center being slightly greater than to the periphery whereas the reverse was seen for PV perfusion. Tumor size did not affect overall perfusion but it did affect regional HA tumor perfusion.

Prevention of chronic cerebral vasospasm in dogs with milrinone

OBJECTIVE

Delayed cerebral ischemia resulting from vasospasm is a major cause of morbidity and death in patients with aneurysmal subarachnoid hemorrhage. Milrinone, because it inhibits Type IV cyclic adenosine monophosphate-specific phosphodiesterase enzyme in both cardiac and vascular smooth muscle, is a powerful inotrope and vasodilator, but it has little effect on heart rate or blood pressure. Because of these properties, milrinone is an attractive potential therapy after subarachnoid hemorrhage. The purpose of the present study was to investigate the effect of milrinone on chronic experimental cerebral vasospasm.

METHODS

A double-hemorrhage canine model of vasospasm was used to study the efficacy of milrinone. Angiographic vasospasm and systemic hemodynamics were compared in a treatment group of animals that received a loading dose of milrinone (0.05 mg/kg, intravenously) and then slow-release (0.05 microgram/kg/min) milrinone pellets (n = 10) and a control group that received placebo pellets (n = 9), over an 8-day period after the initial subarachnoid hemorrhage. The hemorrhage was created by injection of 4 ml of autologous, nonheparinized, arterial blood into the cisterna magna on Days 1 and 3. Hemodynamic measurements, including cardiac output determinations, were made on Days 0, 1, 3, 6, and 8 with a pulmonary artery catheter, and angiographic vasospasm was assessed on Day 8 by comparison with baseline angiograms.

RESULTS

Treatment with milrinone caused no significant changes in systemic hemodynamics. Angiographic vasospasm, however, was significantly reduced in the Day 8 angiograms for the treated group, compared with the control group (98.28 +/- 14.06 and 67.89 +/- 13.06% of original vessel cross-sectional area, respectively; P < 0.001).

CONCLUSION

Milrinone is effective in preventing chronic cerebral vasospasm in a canine model of experimental chronic cerebral vasospasm. This effect is independent of changes in systemic hemodynamics. Milrinone and related drugs warrant further investigation for the treatment of cerebral vasospasm.

Evaluation of a novel nimodipine delivery system in conscious rats that allows sustained release for 24 h

Methodologies that allow prolonged drug administration in animal models, while minimizing surgery and anesthesia, are an important contribution towards studies in awake conditions. Commercially available drug delivery systems like pellets can be customized for the evaluation of experimental therapies with minimal or no discomfort to animals. Our objective was to evaluate pharmacokinetic and physiologic parameters after subcutaneous implantation of rapid 24 h release nimodipine pellets in rats for their potential use as a delivery system for stroke therapeutics. A day prior to the study Sprague-Dawley rats were anesthetized (halothane, N2O, O2) for femoral vessel cannulation and later returned to their cages. On the day of the study the rats were briefly anesthetized (identical regimen as before), and assigned to two groups: nimodipine (NP) and placebo (PL). NP rats received either 0.5 (n = 4), 1 (n = 3), 2 (n = 2), 4 (n = 2), or 15 (n = 5) mg pellets (Innovative Research of America Inc., Sarasota, FL, USA) and PL, rats (n = 5) received placebo pellets. Nimodipine plasma levels were measured at 1, 3, and 6 h. In addition, the 15 mg NP group was followed at 18 and 24 h. Immediately following decapitation the brain was removed for later determination of nimodipine tissue concentration. The NP 15 mg group showed a significant decline of 10% in MABP from base line to 24 h post implantation (p < 0.001). All NP animals achieved at least 83% of their highest plasma concentration at 1 h and 94% at 3 h. A high degree of correspondence (r2 = 0.95, y = 0.36 + 0.28x, n = 16) between the plasma and brain concentrations of nimodipine was present. Although a significant drop in MABP was observed the drop was no greater than 10% in 24 h. Plasma nimodipine levels for the 15 mg animals were within the cerebrovascular effective range. This is the first report to show that 24 h release nimodipine pellets subcutaneously implanted in rats are a reliable delivery system that allows rapid rise and constant nimodipine plasma levels. Therefore, 24 h release pellets are a suitable alternative to other delivery systems like osmotic pumps.

Brain glucose metabolism in hypobaric hypoxia

Hypobaric hypoxia at one-half atmospheric pressure for 3 wk was reported to increase the brain capillary density and glucose transport at the blood-brain barrier in the adult rat. We examined the metabolic concomitants of these alterations in rats subjected to the same hypoxic insult. Hypoxic rats increased brain glucose and lactate concentrations and decreased brain glycogen. However, hypoxia had no significant effects on regional brain levels of ATP and phosphocreatine or on intracellular pH, indicating successful adaptation to the hypoxic insult. 2-Deoxyglucose studies showed that hypoxia increased the regional metabolic rate for glucose by 10-40%. These results indicate increased glycolysis in the hypoxic rat brain, which probably underlies the increased density of glucose transporters in brain microvessels and the increased blood-to-brain glucose influx in hypoxia.

Adhesion molecules in inflammatory bowel disease

The ability of leucocytes to adhere to endothelium is essential for leucocyte migration into inflammatory sites. Some of these adhesion molecules are released from the cell surface and can be detected in serum. The soluble adhesion molecules intercellular adhesion molecule 1 (ICAM-1), E selectin, and vascular cell adhesion molecule 1 (VCAM-1) were studied in the serum of patients with Crohn's disease, ulcerative colitis, and healthy controls. A second blood sample was taken from patients with active disease after one month of treatment and a third two months after remission was achieved. Tissue expression of the same adhesion molecules was studied by immunohistology. Circulating VCAM-1 concentrations were significantly higher in patients with active ulcerative colitis (n = 11, median = 165 U/ml) compared with patients with inactive ulcerative colitis (n = 10, median = 117 U/ml, p < 0.005), active Crohn's disease (n = 12, median = 124 U/ml, p < 0.02), and controls (n = 90, median = 50 U/ml, p < 0.0001). Within each disease group there were no significant differences in E selectin or ICAM-1 concentrations between the active and inactive states, however, patients with active Crohn's disease had significantly higher ICAM-1 concentrations (n = 12, median = 273 ng/ml) than controls (n = 28, median = 168, p < 0.003). VCAM-1 concentrations fell significantly from pretreatment values to remission in active ulcerative colitis (p < 0.01). In Crohn's disease there was a significant fall in ICAM-1 both during treatment (p < 0.01) and two months after remission (p < 0.02). Vascular expression of ICAM-1 occurred more often and was more intense in inflamed tissue sections from patients with ulcerative colitis and Crohn's disease than from controls. Vascular labelling with antibody to E selectin also occurred more often in patients with active inflammatory bowel disease. In conclusion, increased circulating concentrations of selected adhesion molecules are associated with inflammatory bowel disease. There is also evidence of local upregulation, particularly of ICAM-1. Differential expression of adhesion molecules in tissue may play a part in the initiation of leucocyte migration and local inflammation; the function of circulating adhesion molecules is unknown, but may play a physiological part in blocking adhesion.

Sensitivity of magnetic resonance diffusion-weighted imaging and regional relationship between the apparent diffusion coefficient and cerebral blood flow in rat focal cerebral ischemia

BACKGROUND AND PURPOSE

Magnetic resonance (MR) diffusion-weighted imaging (DWI), a noninvasive procedure, may play an important role in detecting and accurately localizing the extent of evolving infarction within the period immediately following stroke. We evaluated the sensitivity and specificity of DWI in detecting ischemia and compared a quantitative measure derived from the DWI, the apparent diffusion coefficient (ADC), with autoradiographic cerebral blood flow (CBF) in an experimental model of focal cerebral ischemia in rats.

METHODS

MR imaging data were obtained with a General Electric 4.7-T horizontal bore magnet CSI II system with self-shielded gradients. DWI was acquired within 41 +/- 6 minutes (mean +/- SD) after onset of ischemia and repeated at 169 +/- 14 minutes, followed by CBF determination at 237 +/- 21 minutes. DWI, ADC, and CBF images from each animal were then compared.

RESULTS

The sensitivities for detecting an abnormality at 1 and 3 hours for DWI were significantly different, and the sensitivity of 3-hour DWI did not differ from the CBF sensitivity of 99%. A mean +/- SD ADC threshold of 460 +/- 95 microns 2/s was defined as 45% higher than the low ADC in the ischemic core compared with the contralateral ADC. Subthreshold ADC area and ischemic area were significantly correlated (r2 = .69, P < .05). In 19 of 48 regions of interest classified as ischemic (< 35 mL.100 g-1.min-1) from both the 3-hour ADC and CBF images, 3-hour ADC correlated significantly with CBF (r2 = .27, n = 19, P < .05), whereas in the nonischemic regions ADC was inversely correlated with CBF. Several ischemic regions showed a sharp drop in ADC to 37% (P < .001, n = 5) compared with all other regions (n = 43) from 1 to 3 hours.

CONCLUSIONS

Because of the change in the sensitivity of detecting ischemia with DWI, the difference in correlation of CBF with ADC between ischemic and nonischemic cortex, and the presence of several regions in which ADC dropped to 37% from 1 to 3 hours, our data suggest that ADC values potentially can be used to monitor evolving infarction.

Cortical cerebral blood flow cycling: anesthesia and arterial blood pressure

Cycling of various cerebral metabolic substances, arterial vascular diameter, and flow has been noted by many workers at a frequency near 0.1 Hz. Suspicion that this phenomenon is dependent on the type of anesthesia led us to investigate the occurrence of cerebral blood flow (CBF) cycling with different anesthetics. Fifteen Sprague-Dawley rats were anesthetized with either pentobarbital (n = 5, 40-50 mg/kg), alpha-chloralose (n = 5, 60 mg/kg), or halothane (n = 5, 1-0.5%). Body temperature was maintained at 37 degrees C. Femoral arterial and venous catheters were placed, and a tracheotomy was performed, permitting artificial ventilation with 30% O2-70% N2. A closed cranial window was formed over a 3-mm diameter craniotomy. Mean arterial pressure (MABP), arterial partial pressures of CO2 and O2 (PaCO2 and PaO2), and pH were controlled and stabilized at normal values. CBF was determined using laser Doppler flowmetry. To induce cycling, MABP was transiently and repeatedly lowered by exsanguination. Fast Fourier analysis of selected 64-s flow recordings (n = 38) was performed. CBF cycling was observed, independent of the type of anesthesia, in all animals. In 36 epochs, cycling was induced when MABP was reduced to a mean pressure of 65 +/- 1.5 mmHg. The mean frequency and amplitude were 0.094 +/- 0.003 Hz and 6.6 +/- 0.5%, respectively. Cycling occurred without blood withdrawal in two epochs. With the use of the blood-withdrawal epochs (n = 36), all three anesthetics shared a common linear slope between amplitude and blood pressure (P < 0.02) and blood pressure change (P < 0.01). Pentobarbital differed from alpha-chloralose and halothane in the relation between cycling frequency and blood pressure. Only pentobarbital exhibited correlation between frequency and blood pressure (P < 0.02) and blood pressure change (P < 0.001). The occurrence of these oscillations is not related to the type of anesthesia, and they usually occur at MABP values that are near or just above the lower limit of autoregulation. At this pressure level, CBF oscillations would suggest that vasoconstrictive and dilatory forces are no longer in balance, but alternatively vying for control.

Estimation of cerebral blood flow from thermal measurement

A thermal method has been developed to quantify continuous perfusion changes with self-calibration. A dynamic, one-dimensional bio-heat transfer model of the thermal probe and tissue describes the system response to either continuous or transient heating. A nonlinear least-squares fit of the model to experimental data yields estimates of the baseline perfusion and other model parameters. With a partial analytical solution of the model, the optimal estimation procedure is two orders of magnitude more efficient than with a total numerical solution of the model system. Experimental data is used to estimate the operating relations between perfusion and the temperature measurement. A new procedure has also been presented to obtain the dynamic response of the system for continuous measurement of perfusion.

Thermal method for continuous measurement of cerebral perfusion

A new thermal system using constant heating power for continuous measurement of cerebral perfusion is presented. It is designed and implemented for optimal perfusion sensitivity and dynamic response based on heat-transfer analysis of perfused brain tissue with thermistors on the cortical surface. Two matched thermistors are used, one to serve as a perfusion sensor and the other to compensate for the base-line temperature changes. To improve the signal-to-noise ratio of the measurement system, lock-in amplifiers are used to minimise long-term drift and low-frequency noise. Errors in the measurement caused by electrical and thermal fluctuations are tested and analysed. In vitro tests show that the measurement accuracy of temperature change is better than 10(-3) degrees C, and the temperature resolution is even greater. In vivo evaluation confirms that the system is responsive to cerebral perfusion changes associated with sudden changes in mean arterial blood pressure caused by bolus injection of norepinephrine, blood withdrawal and blood infusion. The dynamic response of the system is sufficient to detect the autoregulatory perfusion changes in response to arterial blood pressure alteration and the oscillations of cerebral blood flow.

Mucosal interleukin-6 secretion in ulcerative colitis. Effects of anti-inflammatory drugs and T-cell stimulation

BACKGROUND

We have studied modulation of mucosal interleukin-6 (IL-6) secretion by T-cell activation and by anti-inflammatory agents in inflammatory bowel disease.

METHODS

In vitro secretion of IL-6 by biopsy specimens from patients with active ulcerative colitis was investigated in the presence of cyclosporin-A (CsA) and drugs that have other anti-inflammatory actions. Biopsy specimens from patients with quiescent ulcerative colitis or controls were stimulated with anti-CD3 antibody to activate mucosal T cells.

RESULTS

Stimulation of control specimens increased IL-6 secretion (median increase, 147%; p < 0.003), which was prevented by CsA. In quiescent ulcerative colitis there was enhanced spontaneous secretion of IL-6 but a smaller, non-significant increase after T-cell activation (125%). Dexamethasone inhibited secretion in active ulcerative colitis (p < 0.006). 5-Aminosalicylic acid, 6-mercaptopurine, methotrexate, and indomethacin had no effect. There also tended to be a small reduction with CsA, but this just failed to reach statistical significance.

CONCLUSIONS

In quiescent ulcerative colitis the enhanced spontaneous secretion of IL-6 may be a consequence of mucosal T-cell or macrophage activation: the smaller increase after T-cell stimulation suggests that one or both of these two cell types are already pre-activated.

Magnetic resonance diffusion-weighted imaging: sensitivity and apparent diffusion constant in stroke

Magnetic resonance diffusion-weighted imaging (MR-DWI) is sensitive to the diffusibility of water and may offer characterization and anatomical localization of stroke leading to early tailored therapeutic intervention. We compared DWI, the apparent diffusion constant (ADC), and autoradiographic cerebral blood flow (CBF) in a model of focal cerebral ischemia in the rat. Sprague-Dawley rats were embolized with a single silicone cylinder injected into the internal carotid artery. Both common carotids were permanently ligated. The animals were anesthetized (isoflurane in O2), and paralyzed (gallamine). MR-DWI were obtained with a GE 4.7 T magnet (TE = 3 s, TR = 80 msec, b = 2393.10(-3) mm2/s, slice thickness 3 mm). DWI and CBF autoradiograms were compared visually. ADC was assessed in various regions, including ischemic cortex and a region homologous to ischemic cortex. Imaging times from stroke onset were 50 +/- 6 min (mean +/- SEM) for DWI, 185 +/- 17 min for a second DWI. CBF was determined at 258 +/- 15 min. The specificity was 100% at both 50 min and 185 min, indicating that there were no false positives; in 3 animals ischemia was not present. However, the sensitivity analysis indicated that early DWI yields some false negatives; at 50 min the sensitivity was 60%. We attribute our result of low early sensitivity to small infarcts in relation to the slice thickness. Later, at 185 min, sensitivity was 100%. The first ADCs were higher than the second ADC values in ischemic cortex. For infarcts larger than the slice thickness, early MR-DWI is highly sensitive for imaging evolving ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)