Hormone replacement therapy and serum angiotensin-converting-enzyme activity in postmenopausal women

The mechanisms by which hormone replacement therapy (HRT) reduces the risk of coronary heart disease (CHD) are incompletely understood, but may include direct arterial effects. We examined the effect of oestrogen/progestagen HRT on serum angiotensin-converting-enzyme (ACE) activity in postmenopausal women. After 6 months, ACE activity was reduced by 20% (p < 0.001) on average in 28 treated women but remained unchanged in 16 controls. Serum ACE activity is modifiable by gonadal steroids and changes in serum ACE may represent a novel mechanism by which HRT reduces CHD risk in women.

Ocular toxicity of desferrioxamine: light microscopic histochemical and ultrastructural findings

This study documents for the first time light and electron microscopical changes in the retinal pigment epithelium (RPE) following treatment with high dose desferrioxamine for systemic iron overload. The changes include loss of microvilli from the apical surface, patchy depigmentation, vacuolation of the cytoplasm, swelling and calcification of mitochondria, and disorganisation of the plasma membrane. In addition, Bruch's membrane overlying degenerate RPE cells appeared abnormally thickened owing to the accumulation of large amounts of mature elastic fibres, pre-elastic oxytalan, and long spacing collagen. The specificity of these changes and the mechanism of toxicity are discussed.

Screening for osteopenia and osteoporosis: do the accepted normal ranges lead to overdiagnosis?

Osteoporosis is a common disease which causes significant morbidity and mortality and in many cases may be preventable. In the absence of fragility fractures the accepted method of identifying those at high risk is based upon bone mineral density (BMD) measurements with defined cut-off points. To correctly delineate normal from abnormal, reliable reference ranges appropriate to the observed population are required. We have studied the age-dependent changes in mean BMD and standard deviation at the lumbar spine and femoral neck in a normal population extracted from 4280 women screened for osteopenia and compared our findings with the manufacturer's normal range (MNR). The recent World Health Organization criteria for the diagnosis of osteopenia and osteoporosis using the 'manufacturer's young normal' (MYN) values and our 'study young normal' (SYN) values have been applied. The study normal population (SNP) included 2068 women (mixed social class; mean age 53 years, range 30-79 years). The distribution of mean lumbar spine BMD with age in SNP was generally similar to the MNR. In contrast mean femoral neck bone density from SNP was significantly different from the MNR, ranging from 3% to 12% lower in each 5-year group analysed (p < 0.05). Comparison of standard deviations in spine BMD in SNP against the fixed MNR standard deviation showed a statistically significant increase commencing at 45 years of age. The magnitude of this increase appeared to rise with age and remained significant in the 75- to 79-year age group (p < 0.05). In contrast, standard deviation in femoral neck BMD in SNP appeared relatively constant with age except in the group of women at and around the time of the menopause. The SYN value for mean lumbar spine BMD was 0.994 g/cm2 (cf. MYN value 1.047, p < 0.0001) with a standard deviation of 0.122 g/cm2 (cf. MYN 0.11, p = 0.0005). Similarly our SYN value for femoral neck BMD was 0.787 (cf. MYN value 0.895, p < 0.0001) with a standard deviation of 0.109 (cf. MYN value 0.10, p = 0.0027). Using SYN values 36% (748) for the spine and 33% (675) for the hip of our normal population are classified as osteopenic or osteoporotic. Using MYN values increases the proportion of women classified as osteopenic or osteoporotic to 52% (1078) for the spine and 68% (1409) for the femur. If both sites of measurement are considered simultaneously SYN classifies 46% (952) as either osteopenic or osteoporotic at one or other site, which is increased to 73% (1513) when the MYN values are used. We observe that manufacturer's reference ranges may not be appropriate for the local population and may lead to an erroneously high diagnosis of osteopenia and osteoporosis, which would lead to unnecessary patient anxiety and perhaps errors regarding treatment.

Formation of stable crystalline enzyme-substrate intermediates at sub-zero temperatures

Sub-zero temperatures can be used to trap intermediates in enzyme-catalysed reactions using suitable cryosolvents. The feasibility of obtaining such intermediates in the crystalline state for X-ray diffraction studies has been demonstrated with several proteases, using specific substrates and optimal pH.

Decompressive craniectomy for acute disseminated encephalomyelitis

BACKGROUND

Acute disseminated encephalomyelitis (ADEM) is a rare, acute demyelinating condition. Although it usually presents in an acute or subacute manner over days, its clinical course may be rapid with symptoms and signs of severe intracerebral mass effect secondary to cerebral oedema.

METHODS

Case report and literature review.

RESULTS

We report a case of a patient presenting with a hyperacute course manifested by rapid loss of consciousness and focal neurological signs. Management with emergency hemicraniectomy and steroids resulted in rapid neurological improvement and minimal long-term deficit.

CONCLUSIONS

We believe that only surgical decompression is likely to be life saving in similar cases of hyperacute cerebral oedema due to ADEM. The wide decompression performed was concordant with that indicated for traumatic brain swelling. Such aggressive management is vindicated by the rapid recovery shown by our patient within days of surgery and the finding of minimal neurological sequelae at 3 months.

Review of 3,530 referrals for bone density measurements of spine and femur: evidence that radiographic osteopenia predicts low bone mass

PURPOSE

To determine the relationship between bone mineral density (BMD) measurements and the initial reason for referral to a BMD screening service.

MATERIALS AND METHODS

Referral letters for 3,479 of the 3,530 women referred for BMD screening were classified according to the indication for screening. Mean age-matched standard deviation scores (Z scores) were derived for each of the 10 most common indications. Mean BMD between each group was compared with the age-matched value from the local normal range by means of a one-sample Student t test. Mean young normal standard deviation scores (T scores) were derived, and the percentages of women with osteopenia or osteoporosis from each referral group were calculated on the basis of the World Health Organization criteria.

RESULTS

The most common reason for referral was to aid in a decision regarding hormone replacement therapy (n = 700). The highest proportion of women with osteoporosis in any group was in the radiographic osteopenia group (n = 269).

CONCLUSION

Radiographic evidence of osteopenia is a strong predictor of osteoporosis. Screening for osteopenia appears justified in this and other high-risk groups and those seeking a rationale for preventive therapy.

Lipid keratopathy and atheromatosis in an SPF laboratory rabbit colony attributable to diet

Sporadic cases of corneal opacity occurred in an SPF rabbit colony fed on a diet containing 10% white fish-meal. Routine histological monitoring also revealed atheromatous lesions involving the intima of the aorta, coronary arteries and the arteries of other organs in 29 rabbits examined. Serum cholesterol levels above 10 mmol/l were found in 7 rabbits, including 4 affected with corneal lesions, which proved to be lipid keratopathy on histochemical and electron microscopical examination. The serum cholesterol level was found to be within normal range (below 2.27 mmol/l) in 10 rabbits reared entirely on a modified version of the diet, where the 10% fish-meal content was replaced with 10% grass-meal. No more ocular or atheromatous lesions have been found since the adoption of the new diet for the colony.

Trypanosome infection rate of Glossina morsitans submorsitans in Bahr El Arab, South Darfur Province, Sudan

Trypanosome infection rate of Glossina morsitans submorsitans in Bahr El Arab fly belt, Sudan was investigated in four areas using fly rounds with screen and bait animals together with traps during the dry season February to May 1985. The overall infection rate of tests flies captured in the four areas was 5.1%. The infection rate of vivax group trypanosomes comprised 64.7% of total infections, congolense group 31.2% and brucei group trypanosomes 3.9%: 27.3% of the vivax and 31.3% of the congolense were immature trypanosome infections. Mixed trypanosome infections were encountered in a few flies. Trypanosome infection rate of flies differed with the sampling technique employed. A linear positive correlation existed between the physiological age of males and their trypanosome infection rates.

Physiological and pathobiological significance of ocular glycoproteins. I. Studies using fluorescein labelled glycine max

Cell surface carbohydrates play an important role in several biological, immunological, and neoplastic phenomena including development, growth regulation, cellular locomotion, receptor activation, and tumour metastasis. Fluorescein labelled lectins which bind to specific carbohydrate residues in glycoproteins and glycolipids are being increasingly used as chemical probes to study cell components. Several different preparations of ocular tissues from human, rabbit, and rat were examined for the distribution of N-acetyl-D-galactosamine (D-gal NAc) by means of fluorescein-labelled lectin from soybean (glycine max). A very strong fluorescence was observed in the corneal epithelium; Descemet's membrane and corneal endothelium were also strongly fluorescent. The conjunctival epithelium similarly showed a strong reaction, as did the goblet cells. The iris epithelium and the dilator pupillae were only weakly fluorescent, but the ciliary body showed strong fluorescence, as did the blood vessels. As compared with lens fibres the lens epithelium was strongly fluorescent. The outer retina, that is, the photoreceptors, the pigment epithelium, and Bruch's membrane, showed a very strong reactivity. The optic nerve showed moderate fluorescence, but reaction with extraocular muscles was variable. The skin of the upper and lower eyelids, hair follicles, and blood vessels showed strong lectin binding. Sections of retinoblastoma and malignant melanoma showed no reaction. The physiological and pathological significance of these findings is discussed.

Molecular epidemiology of avian influenza virus and incidence of H5 and H9 virus subtypes among poultry in Egypt in 2009-2011

Egypt has experienced outbreaks of avian influenza (AI) since 2006. A total of 3583 cloacal swabs were collected from chickens, ducks, geese and turkeys from commercial farms, backyards and local bird markets in Qena and Luxor governorates in South Egypt during 2009-2011. These samples were examined for the presence of AI virus (AIV) and positive samples were further subtyped for the H5 and H9 by real time RT-PCR. In this way, 202 (5.64%) samples were found to be AIV-positive of which 186 (92.08%) and 7 (3.46%) belonged to H5 and H9 subtypes, respectively. Higher infection rates were observed in backyard birds and birds from local bird markets in comparison to birds from commercial farms. In conclusion, the predominance of H5 infection indicates a need for continuous monitoring of AIV among avian species and the awareness against public health risk.

Intake and digestibility of berseem (Medicago sativa) and Sorghum Abu 70 (Sorghum vulgare) forages by Sudan zebu cattle and desert sheep

Two experiments were carried out with Sudan zebu cattle and desert sheep to study the voluntary intake and digestibility of berseem (Medicago sativa) and Abu 70 (Sorghum vulgare) forages when offered ad lib. alone and with supplements of molasses to the cattle and dura grain to the sheep. In both experiments the intake of berseem was significantly higher than Abu 70. Supplementation increased Abu 70 intake and while molasses significantly increased berseem intake by cattle, dura decreased its intake by sheep. On the basis of metabolic body size sheep showed a higher intake of these forages than cattle. There was no significant difference in DM digestibility between berseem and Abu 70 by cattle. Sheep digested berseem significantly better than Abu 70. Molasses and dura significantly increased the digestibility of Abu 70 by cattle and sheep but had no significant effect on the DM digestibility of berseem.

Comparison of the immune response between local manufactured and commercial inactivated Newcastle Disease Virus vaccine in a challenge trail with field isolated Newcastle Disease Virus

     Velogenic Newcastle Disease Virus was isolated from broiler chickens in Northern Iraq. An inactivated vaccine was manufactured locally using as seed virus ELD50/ml109 and then compared with commercial inactivated vaccine in an experimental study which included 120 broiler chicks divided into three groups (G1 unvaccinated control, G2 for commercial vaccine and G3 for local vaccine). The chicks were injected subcutaneously at 3 days old followed by booster Lasota live vaccine eye drop. Indirect ELISA technique was used to estimate the antibody titer from the collected sera of chicks at age 7, 17 and 27 days (pre-challenge) and challenged at 31 days old with the same virus. The results indicated that there were significant differences (P<0.05) between vaccinated group G2 and G3 at 27th day old and showed a high antibody level with high protection percentage compared with the control. G1 which shown no survival, 100% mortality and severe histopathological lesions, while in G2 and G3 was 43% and 87% respectively. Post-challenge antibody titers of survival chicks showed in G3 significantly over the G2 with less severe histopathological lesions. This study concluded that vaccine failure could occur due to factors of the immune status of the host, improper storage of vaccine, improper vaccination and variant pathogenic virus strain. More epidemiological surveillances are required to decide the actual impact of the disease in poultry farms and   matching the vaccines.

Incremental prognostic value of calcified vs non-calcified plaque burden on computed tomography angiography and myocardial perfusion imaging

Funding Acknowledgements

Type of funding sources: None.

Background

Coronary computed tomography angiography (CCTA) is currently guideline-endorsed for diagnosing suspected coronary artery disease (CAD) in low-intermediate risk patients. Single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) has an established role in both the accurate detection of ischemia and identification of patients at high risk of future cardiovascular events. Recent studies have shown that the burden of atherosclerotic plaque is an independent predictor of cardiovascular events, and that this effect depends on the degree of calcification.

Purpose

To compare the incremental prognostic value of calcified vs non-calcified plaque burden to CCTA anatomic assessment and SPECT physiologic assessment in patients evaluated with both tests.

Methods

Consecutive patients who underwent clinically indicated CCTA and SPECT myocardial imaging for suspected CAD were included. Ischemia on SPECT was defined as summed difference score &gt; 0 using perfusion graded on a 5-point scale. Anatomically obstructive CAD by CCTA was defined as ≥50% in the left main artery and ≥70% stenosis severity in proximal, mid and distal branches of the left anterior descending, left circumflex and right coronary artery without including side branches. Segment involvement score was defined as the sum of segments with plaque irrespective of the degree of stenosis using an 18-segment coronary artery model. A Hounsfield unit threshold of &gt; =130 was used to classify plaques composition as calcified/mixed (C-SIS) vs non-calcified plaque (NC-SIS). Patients were followed for major adverse cardiovascular events (MACE, inclusive of all-cause death, non-fatal myocardial infarction, and percutaneous coronary intervention or coronary artery bypass grafting 90-days after imaging test.)

Results

A total of 956 patients were included. (Mean age 61.1 ± 14.2 years, 54% men, 89% hypertension, 81% diabetes, 84% dyslipidemia). Obstructive stenosis (left main ≥ 50%, all other coronary segments ≥ 70%) and ischemia were observed in similar number of patients (14%). After a median follow-up of 31 months, 102 patients (11%, 29.2 events per 1000 person-year) experienced a MACE. In multivariable Cox regression models, C-SIS, but not NC-SIS significantly predicted outcomes and improved risk discrimination in models with CCTA obstructive stenosis (HR 1.14 95% CI 1.08 - 1.20 p= &lt;0.001; Harrel’s C 0.74, p = 0.011) and SPECT ischemia (HR 1.14 95% CI 1.08 - 1.20, p &lt; 0.001; Harrel’s C 0.76, p = 0.015).

Conclusion

In the current study of high-risk patients with suspected CAD, calcified plaque burden, but not non-calcified plaque incrementally added to measures in predicting incident cardiovascular outcomes

Antifreeze glycoproteins from an Antarctic fish. Quasi-elastic light scattering studies of the hydrodynamic conformations of antifreeze glycoproteins

A quasi-elastic light-scattering technique was used to study the hydrodynamic conformations of antifreeze glycoproteins from an Antarctic fish. Antifreeze glycoprotein is composed of repeating units of Ala-Ala-Thr, with each threonine O-linked to a disaccharide, and it exists as several polymers of different numbers of this repeating unit. Molecular weights of the two major active polymers are 10,500 and 17,500 by such methods as centrifugation and osmotic pressure, but smaller than 20 by freezing-point depression. Translational diffusion coefficients at 20 degrees were 8.35 times 10-7 cm2 s-1 and 6.15 times 10-7 cm2 s-1 for the M-r-10,500 and 17,500 polymers, respectively. Measurements at -0.2 degrees in the presence of ice crystals did not indicate any conformational changes that might be related to the lowering of the freezing temperature. Lowering the temperature of these glycoprotein solutions close to temperatures of freezing caused a decrease in the effective hydrodynamic radius of both active and inactive glycoprotein components.

Racial disparities of internet access in the united states: a multiyear analysis of the national behavioral risk factors surveillance system

Introduction

The COVID 19 pandemic has led to a dramatic rise in the use of Telehealth. Studies have shown racial/ethnic disparities in internet access, a basic prerequisite for telehealth. However, little is known on the extent of this “digital divide” amongst racial minorities with cardiovascular comorbidities.

Purpose

To investigate racial disparities in internet access amongst those with cardiovascular diseases and risk factors, and explore the degree to which this exists amongst those with different levels of comorbidities.

Methods

Behavioral Risk Factors Surveillance System data from the years 2013–2017, during which survey respondents were asked the main outcome of interest (“Have you used the internet in the past 30 days”) were pooled. Respondents were included if they responded yes to questions on selected cardiovascular diseases and risk factors of interest. Multivariable logistic regression was used to analyze the odds of internet use by racial groups adjusting for several socioeconomic factors.

Results

There were a total of 1,478,214 individuals representing 150,235,244 million adults (non-Hispanic Blacks 11.31% and Hispanics 13.75%). Hispanics and Non-Hispanic Blacks reported the lowest prevalence of internet use (66.1% and 64.4% respectively) compared to Non-Hispanic Whites (81.9%). On regression analysis, racial minorities consistently reported lower rates of internet use, averaging 50% lower odds compared to non-Hispanic Whites. Results remained statistically significant even after controlling for several sociodemographic variables.

Conclusion

Using a large nationally representative cohort, we demonstrated differences in internet access amongst racial minorities and those with multiple comorbidities, placing them at distinct disadvantage with access to telecare. Our study adds to a growing body of literature that shows the disproportionate impact of the pandemic on minorities and calls for a concerted effort to reduce disparities in healthcare delivery.

Funding Acknowledgement

Type of funding sources: None.

Exercise capacity as a predictor of coronary microvascular dysfunction

Introduction

Exercise capacity (EC) is an important prognostic test in patients with coronary artery disease (CAD). Positron-emission tomography (PET) is an important risk-stratifying tool to tailor management of patients with coronary artery disease.

Purpose

We aimed to assess EC in predicting positron emission tomography (PET) myocardial perfusion imaging (MPI) derived coronary flow reserve (CFR).

Methods

Consecutive patients who had clinically indicated PET MPI and EC were included. EC was defined based on peak metabolic equivalents (METS) achieved during exercise stress test. Myocardial blood flow (MBF) in ml/gm/min was obtained from dynamic PET MPI images at rest and peak hyperemia. The coronary flow reserve (CFR) was calculated as the ratio of stress to rest MBF of the left ventricle.

Results

The study population consisted of 511 patients who underwent PET MPI and EC testing (mean age 56 (±11), 71% male). Cardiovascular risk factors were prevalent (75% hypertensive, 82% dyslipidemic, 43% diabetics, 27% known CAD). Peak METS &gt;6 was achieved in 81% of patients, and the CFR &lt;2 was present in 27%. In multivariable logistic regression models adjusted for age, sex, cardiovascular risk factors (hypertension, diabetes, dyslipidemia) and medication use (angiotensin converting enzyme inhibitor/angiotensin receptor blocker, statins, beta-blockers), patients with peak METS &gt;6 had a statistically significant lower odds of microvascular dysfunction (CFR &lt;2: OR 0.43, 95% CI 0.26–0.71, p=0.001). Assessment of discrimination showed the model with CFR &lt;2 had an incremental improvement of Harrell's C statistic over clinical variables (0.65 vs 0.69, p=0.02).

Conclusion

Our findings showed exercise capacity was a good predictor of CFR and microvascular coronary health over and above clinical variables. Further studies are needed to assess the prognostic interplay between EC and CFR.

Funding Acknowledgement

Type of funding sources: None.

Prognostic value of computed tomography derived fractional flow reserve

Introduction

Cardiac computed tomography angiography (CCTA) derived fractional flow reserve (FFRCT) has been shown to add incremental diagnostic value by providing functional severity of coronary lesion in patients with coronary artery disease (CAD).

Purpose

We aimed to assess the prognostic value of FFRCT in patients with suspected CAD.

Methods

Consecutive patients who had clinically indicated CCTA and FFRCT determination at a tertiary care cardiology practice were included. FFRCT was determined off-site using computational flow dynamics. Patients were followed for major adverse cardiovascular events (MACE, inclusive of all-cause death, non-fatal myocardial infarction, and late percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) 90-days after imaging test.)

Results

A total of 667 patients with at least Coronary Artery Disease Reporting & Data System (CAD-RADS) 2 were included. Mean age was 68±10 years, 37% were women, 73% had hypertension, 12% had diabetes and 61% had dyslipidemia. More than half (57%) of the patients had moderate (CAD-RADS 3) stenosis. FFRCT&lt;0.8 was found in 59% of patients, with increasing percent across categories of CAD-RADS. After a median follow-up of 9 months, 52 patients (7.2%, 6.7 events per 1000 person-year) experienced a MACE. In multivariable Cox regression models adjusted for age and sex, FFRCT &lt;0.8 significantly predicted outcomes (HR 2.48 95% CI 1.26–4.87 p=0.008). Sensitivity analysis using lower thresholds of FFRCT failed to show similar results in intermediate stenosis.

Conclusion

Our results suggest that in a real-world cohort of patients with suspected CAD, FFRCT can identify patients at higher risk of incident cardiovascular outcomes.

Funding Acknowledgement

Type of funding sources: None.