Women and stroke: disparities in clinical presentation, severity, and short- and long-term outcomes

Objectives

There are limited data from the Middle East on sex-related differences in short- and long-term stroke outcomes. We present 8 years of experience based on the Qatar stroke database.

Setting

The Qatar stroke database prospectively collects data on all stroke patients admitted to Hamad General Hospital. For this study, we compared female and male acute ischemic stroke patients on their characteristics at admission, short-term outcomes [modified Rankin Scale (mRS) score], and long-term outcomes [incidence of major adverse cardiovascular events (MACEs)].

Participants

A total of 7,300 patients [F: 1,406 (19.3%), M: 5,894 (80.7%); mean age 55.1 ± 13.3 (F: 61.6 ± 15.1, M: 53.5 ± 12.3; p < 0.001)] were admitted with acute ischemic stroke.

Results

Significantly fewer women presented within 4.5 h of onset (F: 29% vs. M: 32.8%; p = 0.01). Although women were more likely to experience severe stroke (NIHSS >10; F: 19.9% vs. M: 14.5%; p < 0.001), fewer were treated with thrombolysis (F: 9.8% vs. M: 12.1%; p = 0.02). Women experienced more medical complications (F: 11.7% vs. M: 7.4%; p < 0.001) and tended to have a more prolonged length of stay in the hospital (F: 6.4 ± 7.6 days vs. M: 5.5 ± 6.8 days; p < 0.001).

Primary and secondary outcome measures

Good outcomes at 90 days (mRS score of 0-2) were less frequent in women (F: 53.3% vs. M: 71.2%; p < 0.001). Fewer female patients were taking antiplatelets (F: 78% vs. M: 84.8%; p < 0.001) or statins (F: 81.2% vs. M: 85.7%; p < 0.001). Significantly more female patients experienced a MACE (F: 12.6% vs. M: 6.5%; p < 0.001).

Conclusion

Older age at presentation contributes to poor outcomes following acute stroke in women. Other contributing factors include delays in admission to the hospital, lower rates of thrombolysis, and lower rates of provision of preventative treatments.

Measles pneumonitis, an important cause to recognize in the era of COVID-19, a case report

Measles is an acute febrile viral illness with a characteristic rash. It is usually present in children. Due to the vaccine's development and wide use, serious complications are quite infrequent in vaccine-covered areas.

Case Presentation

A 36-year-old immunocompetent woman presented with a fever and a macular rash affecting the face and upper trunk. She was found to have transaminitis and later developed bilateral pulmonary infiltrates with decreased oxygen saturation. After extensive work, the measles PCR returned positive results. The patient was treated conservatively until she recovered.

Discussion

Measles pneumonitis is a rare complication that usually occurs in immunosuppressed patients. Due to the coronavirus disease pandemic, diagnosis can be difficult, especially if the presentation is not classic.

Conclusion

We report this case to emphasize the importance of correct diagnosis and proper management.

Abstract TP192: Compared To Men, Women Have Worse Outcome In Acute Stroke: An Eight-years Prospective Study From Qatar

Hypothesis: There is considerable evidence that women have poor outcome following acute stroke when compared to men. We report our experience from a large prospective stroke database from Qatar.

Methods: The Qatar stroke database is a prospective study, which began enrolling patients in 2014. We collected data on the demographics, clinical presentation, investigations, treatments, hospital complications and outcome (measured as 90-days modified Rankin Score [mRS]) on all patients admitted with acute stroke to the Hamad General Hospital where ~95% of stroke patients in Qatar are admitted. Multivariate analysis of risk factors, stroke type and severity, and in-hospital complications were compared to determine 90-days and one-year outcome in men and women.

Results: There were 7300 stroke patients (women:1406 [19.3%], men:5894 [80.7%] admitted between 2014-2021. Multivariate analysis revealed significantly higher rates of obesity (OR 2.51), increasing age (age>65 years [OR 3.79]) and atrial fibrillation (OR 1.26) in women, p<0.001. In women, thrombolysis was less frequent and poor outcome (mRS 3-6) was more frequent (OR 1.62, p< 0.001) after adjustment for risk factors, stroke severity and in-hospital complications. The one-year mortality was significantly higher in women (11.7% versus men: 5.1%, p<0.001).

Conclusions: In this large series of prospectively collected acute stroke patients from Qatar, our study reveals that women are more likely to have a poor outcome when compared to men. Although there was a higher incidence of obesity and previous CAD in women, we were unable to explain the reasons for the poor outcome at 90 days and one year.

Neurocysticercosis in non-endemic regions: The experience of Qatar

Objective

To describe the occurrence and features of Neurocystircercosis (NCC) in Qatar.

Background

Qatar has a mixed population of natives and expats. NCC is not endemic to the region, but clinical practice suggests its occurrence in large numbers.

Design/ methods

A database was created to summarize information retrospectively collected on patients with NCC seen through the national health system (HMC) between 2013 and 2018. We identified demographic and disease related variables (clinical manifestations, investigative findings, treatment and outcome) for all patients.

Results

Out of 420 identified NCC patients, 393 (93.6%) were men, and 98.3% were immigrants from NCC endemic countries such as Nepal (63.8%) and India (29.5%). Eighty percent of patients presented with seizures, with the majority (69%) experiencing generalized tonic-clonic seizures. Five percent presented with status epilepticus. Headaches, the second most common complaint, were reported in 18% of subjects. On imaging, 50% had a single lesion while 63% included pathology at the calcified stage. The lesions were parenchymal in 99.5% of cases, predominantly in the frontal lobe (59%). Thirteen percent were diagnosed incidentally on imaging, mainly in the form of isolated calcified non enhancing lesions. Albendazole was received by 55% of patients, and phenytoin was the most prescribed anti-seizure drug (57%). When long term follow up was available, 70% of the patients presenting with seizures were completely seizure free.

Conclusion

NCC is prevalent in Qatar, mainly within the large Southeast Asian immigrant population. NCC is currently a significant contributor to the epilepsy burden in Qatar, often with a good outcome regarding seizure control. NCC with intraparenchymal single lesion shares a large proportion of our cohort.

The efficacy and effectiveness of the COVID-19 vaccines in reducing infection, severity, hospitalization, and mortality: a systematic review

With the relatively rapid development of the COVID-19 pandemic, vaccine development has become crucial for limiting disease transmission. The accelerated growth in the approved COVID-19 vaccines has sparked concerns about their efficacies which have been assessed by many studies. This systematic review compares the efficacy and effectiveness of seven COVID-19 vaccines. A comprehensive systematic literature search was performed using several databases to identify studies reporting the effectiveness or the efficacy of the vaccines. Only 42 studies met our inclusion criteria, which revealed that the COVID-19 vaccines have successfully reduced the rates of infections, severity, hospitalization, and mortality among the different populations. The full-dose regimen of the Pfizer/BioNTech vaccine is the most effective against infections with the B.1.1.7 and B.1.351 variants. Despite of the high effectiveness of some of the COVID-19 vaccines, more efforts are required to test their effectiveness against the other newly emerging variants.

Anaphylaxis and Related Events Post-COVID-19 Vaccination: A Systematic Review

The Coronavirus Disease 2019 (COVID-19), induced by the SARS CoV-2 virus, is responsible for a global pandemic following widespread transmission and death. Several vaccines have been developed to counter this public health crisis using both novel and conventional methods. Following approval based on promising efficacy and safety data, the AstraZeneca, Janssen, Moderna, Pfizer/BioNTech, and SinoVac vaccines have been administered globally among different populations with various reported side effects. Reports of life-threatening anaphylaxis following administration were of particular concern for both healthcare providers and the public. A systematic literature search using PubMed, Embase, Scopus, Web of Science, Science Direct, MedRxiv, and Lens.org databases identified relevant studies reporting anaphylaxis following vaccine administration. This systematic review includes 41 studies reporting anaphylaxis out of 19908 studies that were retrieved for screening. A total of 7942 cases, including 43 deaths, were reported across 14 countries. Most cases occurred following the administration of the first dose. Importantly, the benefits of vaccination far outweigh the risks of anaphylaxis. Subsequently, as populations continue to get vaccinated, it is important for healthcare providers to be able to recognize individuals at risk of developing anaphylaxis. Furthermore, they must be familiar with both the clinical hallmarks and treatment of anaphylactic reactions to minimize long term sequalae and prevent death in vaccinated individuals. This article is protected by copyright. All rights reserved.

A Capstone Laboratory theme investigating properties of non-steroidal anti-inflammatory drugs and their solubilization by cationic surfactant micelles

Research experience is becoming an increasingly crucial element of today's undergraduate science curriculum. In recent years, the establishment of the Course-Based Undergraduate Research Experience Network (CUREnet) has provided a framework for the development of courses aiming to cultivate students' proficiency in undergraduate research techniques while fostering scientific curiosity in a laboratory setting. Capstone Laboratory is one such course that was designed to provide second-year pre-medical students at Weill Cornell Medicine-Qatar with exposure to laboratory techniques to develop their repertoire of research skills. For the past 3 years, Capstone Laboratory has incorporated a project-based learning component involving non-steroidal anti-inflammatory drugs (NSAIDs). The research element of the NSAID-surfactant theme investigated the partitioning of various drugs into cationic surfactant micelles. Structural elements and enzyme inhibition characteristics of NSAIDs were also investigated, while integrating principles of biochemistry, general chemistry, and experimental organic chemistry. By studying drug properties in these contexts, students integrate their learning and develop skills needed for the study and practice of medicine.

Lymphadenopathy Post‐COVID‐19 Vaccination with Increased FDG Uptake May Be Falsely Attributed to Oncological Disorders: A Systematic Review

Coronavirus disease 2019 (COVID‐19) has caused a global pandemic that continues to cause numerous deaths to date. Four vaccines have been approved by the Food and Drug Administration as of July 2021 to prevent the transmission of COVID‐19: Pfizer, Moderna, AstraZeneca, and Janssen. These vaccines have shown great efficacy and safety profile. One side effect that has been widely reported is post‐COVID‐19 vaccination lymphadenopathy. Due to the mimicry of the lymphadenopathy for metastases in some oncologic patients, there have been reports of patients who underwent biopsies that showed pathologic confirmation of benign reactive lymphadenopathy secondary to the COVID‐19 vaccine. Therefore, understanding the incidence of lymphadenopathy post‐COVID‐19 vaccinations will help guide radiologists and oncologists in their management of patients, both present oncologic patients, and patients with concerns over their newly presenting lymphadenopathy. A systematic literature search was performed using several databases to identify relevant studies that reported lymphadenopathy post‐COVID‐19 vaccination. Our results revealed that several cases have been detected in patients undergoing follow‐up fluorodeoxyglucose (FDG)‐positron emission tomography‐computerized tomography scans where lymph nodes ipsilateral to the vaccine injection site show increased uptake of FDG. Thus, knowledge of the incidence of lymphadenopathy may help avoid unnecessary biopsies, interventions, and changes in management for patients, especially oncologic patients who are at risk for malignancies.

Lymphadenopathy has been widely reported post‐COVID‐19 vaccination including patients undergoing follow‐up FDG‐PET‐CT scans which showed increased FDG uptake

Care must be taken before suspecting lymph node metastasis or deciding for lymphadenectomy following COVID‐19 vaccination

The Interplay Between the Immune System, the Renin-Angiotensin-Aldosterone System (RAAS), and RAAS Inhibitors May Modulate the Outcome of COVID-19: A Systematic Review

Since the discovery of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), numerous research has been undertaken to delineate the various effects of the virus which manifests in many ways all over the body. The association between the SARS-CoV-2 invasion mechanism and the renin-angiotensin-aldosterone system (RAAS) receptors, created many debates about the possible consequences of using RAAS-modulating drugs including angiotensin-converting enzyme inhibitors (ACEi) and angiotensin II receptor blockers (ARBs) during the pandemic. Many clinical studies were conducted to assess the outcomes of coronavirus disease 2019 (COVID-19) in patients who use ACEi/ARBs following the arguments claiming to discontinue these drugs as a precautionary measure. Although several studies mainly analyzed the outcomes of the disease, this review aimed to compare specific blood markers in both groups of COVID-19 patients to gain better insight into the interaction of ACEi/ARBs with different body functions during the infection. Several databases were searched using a combination of keywords followed by screening and data extraction. Only 28 studies met our inclusion criteria, the majority of which showed no significant difference between the inflammation markers of COVID-19 patients who used or did not use ACEi/ARBs. Interestingly, 6 studies reported lower inflammatory markers in COVID-19 patients who used ACEi/ARBs, and 6 studies reported better outcomes among the same group. We therefore concluded that the use of ACEi/ARBs may not lead to worse prognosis of COVID-19 and may even play a protective role against the hyperinflammatory response associated with COVID-19.

Regulatory feedback loop between T3 and microRNAs in renal cancer

microRNAs, short non-coding RNAs, influence key physiological processes, including hormonal regulation, by affecting the expression of genes. In this study we hypothesised that the expression of microRNAs targeting thyroid hormone pathway genes may be in turn regulated by thyroid hormone signalling. It is known that the expression of DIO1, a gene contributing to triiodothyronine (T3) signalling, is regulated by miR-224. Thus, we analysed mutual regulation between triiodothyronine pathway and miR-224/miR-452/GABRE cluster. Firstly, we found that miR-452 directly regulates the expression of thyroid hormone receptor TRβ1 in renal cancer cells. In turn, the expression of miR-224/452/GABRE cluster and other microRNAs targeting TRβ1 was influenced by T3 treatment and/or TR silencing. miR-452 expression correlated with intracellular T3 concentrations in renal tumours. In conclusion, we propose a new mechanism of feedback regulation, by which in renal cancer microRNAs regulate the expression of T3 pathway genes, while T3 in turn regulates expression of microRNAs.

Iodothyronine deiodinases and cancer

Thyroid hormones (TH) regulate key cellular processes, including proliferation, differentiation, and apoptosis in virtually all human cells. Disturbances in TH pathway and the resulting deregulation of these processes have been linked with neoplasia. The concentrations of TH in peripheral tissues are regulated via the activity of iodothyronine deiodinases. There are 3 types of these enzymes: type 1 and type 2 deiodinases are involved in TH activation while type 3 deiodinase inactivates TH. Expression and activity of iodothyronine deiodinases are disturbed in different types of neoplasia. According to the limited number of studies in cancer cell lines and mouse models changes in intratumoral and extratumoral T3 concentrations may influence proliferation rate and metastatic progression. Recent findings showing that increased expression of type 3 deiodinases may lead to enhanced tumoral proliferation support the idea that deiodinating enzymes have the potential to influence cancer progression. This review summarizes the observations of impaired expression and activity in different cancer types, published to date, and the mechanisms behind these alterations, including impaired regulation via TH receptors, transforming growth factor-β, and Sonic-hedgehog pathway. Possible roles of deiodinases as cancer markers and potential modulators of tumor progression are also discussed.

Total and free triiodothyronine in human serum

A reliable method has been developed for the determination of total serum T3, dialyzable fraction (DFT3), and absolute concentration of free T3 (AFT3). Total T3 values (mean +/- SD) were: healthy euthyroid subjects, 0.33 +/- 0.07 mug per 100 ml; hyperthyroid patients, 0.71 +/- 0.1 mug per 100 ml; hypothyroid, 0.10 +/- 0.03 mug per 100 ml. Values (mean +/- SD) for DFT3 in these groups were 0.46 +/- 0.14%, 0.78 +/- 0.17%, and 0.16 +/- 0.08%, respectively. Calculated values for AFT3 were: 1.51 +/- 0.4 mmug per 100 ml, 5.00 +/- 0.6 mmug per 100 ml and 0.24 +/- 0.1 mmug per 100 ml, respectively. Dilution of serum before dialysis lowered estimated DFT3 values. Enrichment of serum with labeled T3 in the range examined did not affect DFT3. However, DFT3 was increased by addition of Merthiolate to serum in concentration 1: 10,000 due to displacement of T3 from thyroxine-binding globulin to albumin. The data suggest that triiodothyronine may play a considerably more important role in normal and pathological physiology, as evidenced by kinetic analysis using these data. A metabolic role for T3 equal to that of T4 is indicated.

Type I 5'-iodothyronine deiodinase activity and mRNA are remarkably reduced in renal clear cell carcinoma

The purpose of this study was to compare thyroid hormone metabolism between non-cancerous tumor-surrounding human kidney tissues and renal clear cell carcinomas (RCCC). The material consisted of samples taken from 10 RCCC patients of both sexes and three grades of differentiation, G1 to G3. We showed that, similar to rat tissue, type I 5' monodeiodinase (5'DI) expression is heterogeneous within the human kidney. We also found a poor correlation between 5'DI activity and mRNA level in non-cancerous tumor-surrounding tissue suggesting significant post-transcriptional regulation of 5'DI expression by an unidentified process in the human kidney. In all RCCC tissues both 5'DI activity and mRNA levels were undetectable. This suggests either loss of human 5'DI gene expression during neoplastic transformation or the origination of RCCC from a tubular cell type that does not express 5'DI.

Expression of thyroid hormone receptors is disturbed in human renal clear cell carcinoma

Human renal clear cell carcinoma (RCCC) accounts for up to 2% of human cancers. To find out if thyroid hormone (T3) and its receptors (TRs) play a role in tumorigenesis of RCCC, the expression of TRs was evaluated on mRNA and protein level. It was found that TRalpha (both alpha1 and alpha2) mRNA amount was significantly decreased in tumors while compared with healthy kidney tissue, and this decrease was deepest in G1 (well differentiated) RCCCs. In contrast, TRalpha1 protein was 1.6x overexpressed in tumors. TRbeta1 mRNA amount was overexpressed in 30% and significantly decreased in 70% of examined tumors. On the protein level, TRbeta1 amount was 1.7x lower in tumors than in healthy controls.

The deiodination of thyroxine to triiodothyronine in the testes of patients with prostate cancer

Until recently metabolism and expression of thyroid hormones was considered not to occur in the tissues of the testes. Lately, specific receptors for triiodothyronine have been found in the nuclei of human testicular cells which shows that testicular tissue requires hormonal action [9]. The aim of the present study was to evaluate if the prohormone thyroxine is converted into triiodothyronine within human testes (resected because of prostatic carcinoma) and if hormonal therapy with dihydrostilbestrol (DES), a testosterone antagonist, affects production of the active thyroid hormone. Our earlier studies showed a complete lack of iodothyronine 5'-deiodinase activity in prostatic carcinoma (PC) [7]. The present material consisted of testes from 21 patients with PCs. According to Whitmore's classification 13 patients were at stage C with mean PSA of 70.15 ng/ml and 8 were at stage D with mean PSA of 308.73 ng/ml. Before castration 6 patients (3 stage C and 3 stage D) were pretreated with 3 mg DES daily for 3 days. The resected testes were homogenized and ultracentrifuged. The obtained microsomal fraction was the source of thyroxine 5'-deiodinase (T4-5'-D). In 15 patients, in whom the primary approach was surgical, the specific T4-5'-D activity was not different between stage C and D patients (mean +/- SD): 19.52 +/- 12.55 vs. 22.07 +/- 12.68 fmol de novo produced triiodothyronine/min/mg of microsomal protein, respectively. However, in 6 patients pretreated with DES the activity was significantly decreased, regardless of the degree of differentiation of the prostate carcinoma: 0.70 +/- 0.68 fmol T3/min/mg for stage C and 2.6 +/- 4.5 fmol/min/mg for stage D patients.(ABSTRACT TRUNCATED AT 250 WORDS)

[Regulation of triiodothyronine levels in fatty tissue in obese patients]

Specific activity of T4-5'-deiodinase, the enzyme which catalyze peripheral production of triiodothyronine (T3) from thyroxine (T4) has been evaluated in the subcutaneous adipose tissue of obese patients. In lean healthy women (BMI less than 21) mean activity of T4-5'-D was found to be 122 +/- 29.4 fmol T3/mg of protein/min and was higher then respective activity of the enzyme in adipocytes of patients with mild obesity (22 less than BMI less than 30) where the mean was 92.14 +/- 18.05 fmol T3/mg/min. The activity of T4-5'-D was significantly decreased in patients with severe obesity (BMI less than 30) when compared with respective activity of the enzyme found in controls (47.36 +/- 18.4 fmol T3/mg/min vs 122.4 +/- 29.4 fmol T3/mg/min; p less than 0.01). As T4-5'-D in human adipose tissue has been previously characterized as type II of the enzyme, diminished activity found in obese subjects means that thyroid metabolic activity of adipocyte is decreased. Such a state would lead to antilipolytic action of catecholamines in obesity.

Decrease of rat-liver-T4-5'-deiodinase activity during chronical isoprenaline beta-action in vivo

Pure adrenergic beta-action, brought about by long-term adrenaline + regitine application in rats, was able to increase liver T4-5'-deiodinase activity for 8 h (Nauman et al. 1984a). Long-term isoprenaline application without alpha-blocking yielded contrary results. One of the compensatory mechanism to be probably blamed could have been the very high endogenous adrenaline-levels (Porta et al. 1985). Simultaneous treatment with isoprenaline and alpha-methyltyrosinemethylester did not settle the problem since even then deiodinase activity was still drastically decreased. Two more components have been found which could very well be the reason for that "paradox beta-action" in vivo, namely very low glucose and insulin levels, both of which are known to influence deiodinase activity. In vivo--contrary to in vitro--it is seemingly not possible that catecholaminergic beta-action could increase the peripheral production of T3 unless general alpha-blocking took place.

Failure of bone marrow cryopreservation in chronic granulocytic leukemia: relation to excessive granulo-macrophagic progenitor pool

Autologous bone marrow transplantation (ABMT) in chronic granulocytic leukemia (CGL) aims at reversing the acute or acceleration phases by injection of stem cells collected during the chronic phase. This study was designed to explain an unusual rate of delayed engraftment (50%) in our experience of ABMT in CGL patients. We investigated all the factors possibly responsible for abnormal perpetuation of aplasia following infusion of cryopreserved marrow stem cells. The study of CFU-gm recovery in 41 bags of frozen marrow from 25 patients revealed an overall deficiency with a mean CFU-gm recovery of 55 +/- 38% in CGL patients versus 73 +/- 15% in the control group (p less than 0.001). Our data also showed an inverse linear relation (r = -0.40, p less than 0.05) between CFU-gm concentration and recovery after freezing. A good CFU-gm recovery (greater than or equal to = 50%) was observed in 70% of cases when the concentration was less than 3700 CFU-gm/ml as compared to 30% of cases when the concentration was over 3700 CFU-gm/ml (p less than 0.001). The lack of improvement by diluting rich CFU-gm marrows to reduce CFU-gm concentration/ml, as well as the absence of relationship between CFU-gm recovery after freezing and nucleated cells concentration, suggest a particular fragility of CGL stem cells to freezing, probably related to their excessive amplification. At the present time, we strongly recommend that the highest possible dose of progenitor cells be cryopreserved, preferably at a low concentration, in patients with CGL, and particular attention devoted to the freezing procedure in each individual patient, with numerous appropriate efficiency tests.

The effect of adrenaline pretreatment on the in vitro generation of 3,5,3'-triiodothyronine and 3,3',5'-triiodothyronine (reverse T3) in rat liver preparation

The effects of adrenaline (A) on liver T3 and rT3 neogenesis from T4 were studied in Wistar rats. The animals were implanted subcutaneously either with A or placebo (P) especially coated tablets which linearly released the hormone. The serum A values 6 hrs after implantation of 7.5, 15.0 and 45.0 mg tablets were 6.5 +/- 1.31, 6.8 +/- 1.8 and 16.4 +/- 1.9 ng/ml, respectively vs 4.4 +/- 2.5 ng/ml seen in P pretreated group. The output rates of A were 0.11 (7.5 mg), 0.18 (15 mg) and 0.52 microgram/ml (45 mg). The pretreatment with A led to hyperglycemia and the "low T3 syndrome". Neogenesis of T3 from T4 in medium containing liver microsomes of P pretreated rats was 5.49 +/- 0.25 pmol of T3/mg protein/min and decreased in A pretreated rats to 3.82 +/- 0.17, 3.12 +/- 0.27 and 3.06 +/- 0.11 pmol of T3/mg of protein/min. Neogenesis of rT3 from T4 in microsomes from P group was 1.52 +/- 0.09 pmol rT3/mg protein/min and increased after A to 2.71 +/- 0.11, 2.60 +/- 0.21 and 2.21 +/- 0.34 pmol of rT3/mg protein/min thus showing no dose dependency. Enrichment of microsomes medium with cytosol either from P or A pretreated rats had no effect on T3 generation thus excluding effect of A on cytosolic cofactor. Although cytosol further increased rT3 neogenesis this was seen regardless of whether cytosol was obtained from A or P implanted rats. It is concluded that A decreases the activity of T4-5'-deiodinase in liver, and possibly increases the activity of T4-5-deiodinase.

Influence of surgery and experimental myocardial infarction on blood levels of free fatty acids and triiodothyronine in dogs

Preparatory operations (PO) including thoracotomy have been performed in 11 dogs. After 6 days in 6 dogs the left anterior descending coronary artery (LAD) was ligated leading to development of acute myocardial infarction (MI). Both after PO and during MI and increase in plasma free fatty acids (FFA) and a decrease in serum triiodothyronine (T3) was observed. There was a negative correlation between T3 and FFA 4--22 hours after PO and 9--22 hours after LAD ligation. In control dogs without LAD ligation a positive correlation between FFA and T3 levels was shown 8--18 days after PO during the period of wound healing. It seems that the combination of elevated FFA and depressed T3 reflects the metabolic disturbances which are more pronounced during MI than after surgical operation connected with thoracotomy.

In vivo and in vitro effects of adrenaline on conversion of thyroxine to triiodothyronine and to reverse-triiodothyronine in dog liver and heart

Infusion of adrenaline in healthy dogs in a dose simulating spontaneous release of the catecholamine during experimental myocardial infarction produced a significant decrease in the conversion of thyroxine (T4) to triiodothyronine (T3) and a moderate increase in the conversion of T4 to reverse-triiodothyronine (rT3). Similar changes in deiodination of T4 to T3 and to rT3 were also observed when adrenaline was added in vitro to liver and heart homogenates. These results are consistent with a direct effect of adrenaline on T4 deiodination as degradation of exogenous T4, T3 and rT3 was only slightly increased under the experimental condition employed. The present study suggests that increased tissue exposure to adrenaline might contribute to the hormonal changes seen in at least some case of the 'low T3 syndrome'.

Effects of beta-blocking agent Metipranolol on metabolic variables in patients with ischemic heart disease, hyperkinetic syndrome, hyperthyreosis and in healthy subjects

Metabolic effects of Metipranolol, a new beta adrenergic blocking agent, have been studied in patients with ischemic heart disease, hyperkinetic syndrome, hyperthyreosis and in healthy subjects. Administration of the drug (30 mg per day for one week) resulted in the decrease of noradrenaline excretion, blood free fatty acid level, and in lowering of blood pressure and heart rate, particularly in patients with ischemic heart disease and hyperkinetic syndrome. These alterations were accompanied by alleviation of clinical symptoms. It is suggested that Metipranolol by suppressing the activity of sympathetic nervous system and thereby diminishing lypolysis, exerts favourable clinical effects, most probably related to diminution of myocardial oxygen consumption.

Evidence for the detrimental effect of adrenaline infused to healthy dogs in doses imitating spontaneous secretion after coronary occlusion

We have previously shown that acute coronary occlusion in the dog is often accompanied by increased adrenaline release into the blood. In the present study the consequences of this humoral reaction were studied in anaesthetised healthy mongrel dogs subjected to adrenaline infusion administered at a rate relevant to spontaneous release of this amine in coronary occlusion. Adrenaline was infused in a dose of 1.2 microgram.kg-1.min-1 for 4 h. Dogs receiving saline served as the control. Adrenaline administration led to the decrease in insulin/glucose ratio, to a significant fall in serum triiodothyronine and in blood pH. Free fatty acid levels doubled. Histochemically, a diminution in succinic dehydrogenase and ATPase activity in adrenaline-treated hearts was found. A significant fall in the activity of mitochondrial hexokinase in these hearts was detected spectrophotometrically. Electron microscopic study revealed alterations in the mitochondrial structure. These findings indicate that an excess of adrenaline in ammounts similar to that seen in experimental infarction leads to profound metabolic and hormonal disturbances and exerts a detrimental effect upon myocardium.

The "effective thyroxine ratio"--new in vitro test of thyroid function and its correlation with free thyroxine

The effective thyroxine ratio (ETR) and absolute concentration of free thyroxine (AFT4) were estimated in the sera of 31 normal subjects, 27 hyperthyroid patients, 12 hypothyroid patients and 21 euthyroid pregnant women.

The mean ETR value in the controls was 1.0 ± 0.18, in the hyperthyroid patients 1.31 ± 0.25, in the hypothyroid patients 0.71 ± 0.21 and in normal pregnant women 0.99 ± 0.24. The mean AFT4 in the normal subjects was 3.0 ± 0.53 ng/100 ml, in the hyperthyroid patients 9.49 ± 2.44 ng/ 100 ml, in the hypothyroid patients 0.58 ± 0.15 ng/100 ml and in the pregnant women 2.84 ± 0.63 ng/100 ml, respectively. High reproducibility of ETR and a significant positive correlation between ETR and AFT4 with r = 0.96 suggest that ETR might be a suitable in vitro test for routine clinical evaluation of the thyrometabolic state.