scholarly journals Defibrillate you later, alligator; Q10 scaling and refractoriness keeps alligators from fibrillation

Author(s):  
C Herndon ◽  
H C Astley ◽  
T Owerkowicz ◽  
F H Fenton

Abstract Effective cardiac contraction during each heartbeat relies on the coordination of an electrical wave of excitation propagating across the heart. Dynamically induced heterogeneous wave propagation may fracture and initiate reentry-based cardiac arrhythmias, during which fast rotating electrical waves lead to repeated self-excitation that compromises cardiac function and potentially results in sudden cardiac death. Species which function effectively over a large range of heart temperatures must balance the many interacting, temperature-sensitive biochemical processes to maintain normal wave propagation at all temperatures. To investigate how these species avoid dangerous states across temperatures, we optically mapped the electrical activity across the surfaces of alligator (Alligator mississippiensis) hearts at 23 °C and 38 °C over a range of physiological heart rates and compare them with that of rabbits (Oryctolagus cuniculus). We find that unlike rabbits, alligators show minimal changes in wave parameters (action potential duration and conduction velocity) which complement each other to retain similar electrophysiological wavelengths across temperatures and pacing frequencies. The cardiac electrophysiology of rabbits accommodates the high heart rates necessary to sustain an active and endothermic metabolism at the cost of increased risk of cardiac arrhythmia and critical vulnerability to temperature changes, whereas that of alligators allows for effective function over a range of heart temperatures without risk of cardiac electrical arrhythmias such as fibrillation, but is restricted to low heart rates.

2007 ◽  
Vol 28 (1) ◽  
pp. 123-128 ◽  
Author(s):  
Carlos Piña ◽  
Alejandro Larriera ◽  
Pablo Siroski ◽  
Luciano Verdade ◽  
Valentine Lance

AbstractAll crocodiles studied to date exhibit temperature-dependent sex determination. During the many weeks from egg laying to hatch there is a period of 10 to 15 d in the middle third of incubation (in the American alligator) during which the sex of the embryo is irreversibly fixed, referred to as the temperature-sensitive period or TSP. In this work we investigated the TSP in Caiman latirostris eggs incubated at female-inducing and male-inducing temperatures (29° C and 33° C respectively) by switching eggs from 29° C to 33° C and vice versa at timed interval throughout incubation. Compared to Alligator mississippiensis the duration of TSP was longer, and the onset of TSP was at an earlier stage of incubation.


2020 ◽  
Vol 26 (43) ◽  
pp. 5617-5627
Author(s):  
Mirjana Stojković ◽  
Miloš Žarković

The prevalence of subclinical hypothyroidism (SH) is 3-10%. The prevalence of subclinical hyperthyroidism (SHr) is 0.7-9.7%. Thyroid hormones affect cardiac electrophysiology, contractility, and vasculature. SH is associated with an increased risk of coronary heart disease (CHD), especially in subjects under 65. SHr seems to be associated with a slightly increased risk of CHD and an increase in CHD-related mortality. Both SH and SHr carry an increased risk of developing heart failure (HF), especially in those under 65. Both SH and SHr are associated with worse prognoses in patients with existing HF. SH is probably not associated with atrial fibrillation (AF). SHr, low normal thyroid-stimulating hormone (TSH) and high normal free thyroxine (FT4) are all associated with the increased risk of AF. An association between endothelial dysfunction and SH seems to exist. Data regarding the influence of SHr on the peripheral vascular system are conflicting. SH is a risk factor for stroke in subjects under 65. SHr does not increase the risk of stroke. Both SH and SHr have an unfavourable effect on cardiovascular disease (CVD) and all-cause mortality. There is a U-shaped curve of mortality in relation to TSH concentrations. A major factor that modifies the relation between subclinical thyroid disease (SCTD) and mortality is age. SH increases blood pressure (BP). SHr has no significant effect on BP. Lipids are increased in patients with SH. In SHr, high-density lipoprotein cholesterol and lipoprotein( a) are increased. SCTD should be treated when TSH is over 10 mU/l or under 0.1 mU/l. Treatment indications are less clear when TSH is between normal limits and 0.1 or 10 mU/L. The current state of knowledge supports the understanding of SCTD’s role as a risk factor for CVD development. Age is a significant confounding factor, probably due to age-associated changes in the TSH reference levels.


Author(s):  
Abdul Rahman Ramdzan ◽  
Mohd Rizal Abdul Manaf ◽  
Azimatun Noor Aizuddin ◽  
Zarina A. Latiff ◽  
Keng Wee Teik ◽  
...  

Colorectal cancer (CRC) remains the second leading cause of cancer-related deaths worldwide. Approximately 3–5% of CRCs are associated with hereditary cancer syndromes. Individuals who harbor germline mutations are at an increased risk of developing early onset CRC, as well as extracolonic tumors. Genetic testing can identify genes that cause these syndromes. Early detection could facilitate the initiation of targeted prevention strategies and surveillance for CRC patients and their families. The aim of this study was to determine the cost-effectiveness of CRC genetic testing. We utilized a cross-sectional design to determine the cost-effectiveness of CRC genetic testing as compared to the usual screening method (iFOBT) from the provider’s perspective. Data on costs and health-related quality of life (HRQoL) of 200 CRC patients from three specialist general hospitals were collected. A mixed-methods approach of activity-based costing, top-down costing, and extracted information from a clinical pathway was used to estimate provider costs. Patients and family members’ HRQoL were measured using the EQ-5D-5L questionnaire. Data from the Malaysian Study on Cancer Survival (MySCan) were used to calculate patient survival. Cost-effectiveness was measured as cost per life-year (LY) and cost per quality-adjusted life-year (QALY). The provider cost for CRC genetic testing was high as compared to that for the current screening method. The current practice for screening is cost-saving as compared to genetic testing. Using a 10-year survival analysis, the estimated number of LYs gained for CRC patients through genetic testing was 0.92 years, and the number of QALYs gained was 1.53 years. The cost per LY gained and cost per QALY gained were calculated. The incremental cost-effectiveness ratio (ICER) showed that genetic testing dominates iFOBT testing. CRC genetic testing is cost-effective and could be considered as routine CRC screening for clinical practice.


Geophysics ◽  
2001 ◽  
Vol 66 (6) ◽  
pp. 1838-1842 ◽  
Author(s):  
C. M. Schmeissner ◽  
K. T. Spikes ◽  
D. W. Steeples

Ultrashallow seismic reflection surveys require dense spatial sampling during data acquisition, which increases their cost. In previous efforts to find ways to reduce these costs, we connected geophones rigidly to pieces of channel iron attached to a farm implement. This method allowed us to plant the geophones in the ground quickly and automatically. The rigidly interconnected geophones used in these earlier studies detected first‐arrival energy along with minor interfering seismic modes, but they did not detect seismic reflections. To examine further the feasibility of developing rigid geophone emplacement systems to detect seismic reflections, we experimented with four pieces of channel iron, each 2.7 m long and 10 cm wide. Each segment was equipped with 18 geophones rigidly attached to the channel iron at 15‐cm intervals, and the spikes attached to all 18 geophones were pushed into the ground simultaneously. The geophones detected both refracted and reflected energy; however, no significant signal distortion or interference attributable to the rigid coupling of the geophones to the channel iron was observed in the data. The interfering seismic modes mentioned from the previous experiments were not detected, nor was any P‐wave propagation noted within the channel iron. These results show promise for automating and reducing the cost of ultrashallow seismic reflection and refraction surveys.


2021 ◽  
pp. 105566562110698
Author(s):  
Kristaninta Bangun ◽  
Jessica Halim ◽  
Vika Tania

Chromosome 17 duplication is correlated with an increased risk of developmental delay, birth defects, and intellectual disability. Here, we reported a female patient with trisomy 17 on the whole short arm with bilateral complete cleft lip and palate (BCLP). This study will review the surgical strategies to reconstruct the protruding premaxillary segment, cleft lip, and palate in trisomy 17p patient. The patient had heterozygous pathogenic duplication of chromosomal region chr17:526-18777088 on almost the entire short arm of chromosome 17. Beside the commonly found features of trisomy 17p, the patient also presented with BCLP with a prominent premaxillary portion. Premaxillary setback surgery was first performed concomitantly with cheiloplasty. The ostectomy was performed posterior to the vomero-premaxillary suture (VPS). The premaxilla was firmly adhered to the lateral segment and the viability of philtral flap was not compromised. Two-flap palatoplasty with modified intravelar veloplasty (IVV) was performed 4 months after. Successful positioning of the premaxilla segment, satisfactory lip aesthetics, and vital palatal flap was obtained from premaxillary setback, primary cheiloplasty, and subsequent palatoplasty in our trisomy 17p patient presenting with BLCP. Postoperative premaxillary stability and patency of the philtral and palatal flap were achieved. Longer follow-up is needed to evaluate the long-term effects of our surgical techniques on inhibition of midfacial growth. However, the benefits that the patient received from the surgery in improving feeding capacity and facial appearance early in life outweigh the cost of possible maxillary retrusion.


PEDIATRICS ◽  
1994 ◽  
Vol 93 (1) ◽  
pp. 151-152
Author(s):  
Caroline Breese Hall ◽  
Harold S. Margolis

We appreciate the concerned letter of Dr Jacobs and his thoughtful questions arising both from his knowledge of the recommendations and public health issues, as well as those of private practice. The cost of vaccines is an issue with which we must all be concerned. By highlighting the importance of childhood immunization the Clinton administration has engendered interest and, thus, optimism that efforts toward reducing the cost will be successful. However, we should remember that the many excellent studies that have analyzed the reasons why children are not being vaccinated have shown that cost is not the major factor, but access, difficulties, and obstacles, real and perceived, to obtaining immunizations are.


2018 ◽  
Vol 47 (1-3) ◽  
pp. 259-264 ◽  
Author(s):  
Karen M.  Van de Velde-Kossmann

Renal failure patients have an increased risk of infection, including skin and soft tissue infections. This increased susceptibility is multifactorial, due to the conditions causing the renal failure as well as complications of treatment and renal failure’s innate effects on patient health. These infections have a significant impact on patient morbidity, increased hospital and procedural demands, and the cost of health care. Many renal failure patients are seen regularly by their nephrology clinic caregivers due to the need for frequent dialysis and transplant monitoring. Familiarity with common skin and soft tissue infections by these caregivers allowing enhanced patient education, optimal infection prevention, and early recognition could significantly reduce the morbidity and cost of these disorders, such as diabetic foot syndrome, necrotizing fasciitis, and herpetic infections.


2004 ◽  
Vol 92 (09) ◽  
pp. 590-597 ◽  
Author(s):  
Fredric Chan ◽  
Raymond Wong ◽  
Gregory Cheng ◽  
Joyce You

SummaryVariant cytochrome P450 (CYP) 2C9 genotypes are associated with low maintenance dose requirement of warfarin therapy and increased risk of major bleeding events. The objective of the present study was to evaluate the potential clinical and economic outcomes of using CYP2C9 genotype data to guide the management of anticoagulation therapy and to identify influential factors affecting the cost-effectiveness of this treatment scheme. A decision tree was designed to simulate, over 12 months, the clinical and economic outcomes of patients newly started on warfarin associated with two alternatives: (1) no genotyping (non-genotyped group) and (2) CYP2C9 genotyping prior to initiation of warfarin therapy (genotyped group). Nongenotyped group patients would receive standard care of an anticoagulation clinic (AC). In the genotyped group, patients with at least one variant CYP2C9 allele would receive intensified anticoagulation service. Most of the clinical probabilities were derived from literature. The direct medical costs were estimated from the Diagnosis-Related Group charges and from literature. The total number of events and the direct medical cost per 100 patient-years in the genotyped and non-genotyped groups were 9.58 and USD155,700, and, 10.48 and USD 150,500, respectively. The marginal cost per additional major bleeding averted in the genotyped group was USD 5,778. The model was sensitive to the variation of the cost and reduction of bleeding rate in the intensified anticoagulation service. In conclusion, the pharmacogenetics-oriented management of warfarin therapy is potentially more effective in preventing bleeding with a marginal cost. The cost-effectiveness of this treatment scheme depends on the relative cost and effectiveness of a pharmacogenetics-oriented intensified anticoagulation service comparing to the standard AC care.


Since blood transfusion is linked to the magnitude of the surgical procedure, comparing transfused patients to untransfused patients will always be confounded by infection risks due to factors related to the procedure. To control for these factors one must compare patients transfused with red cells from different sources or prepared in a manner which minimize infection risk. Patients transfused with homologous blood have infection rates several fold higher than recipients of equal values of autologous blood undergoing the same operative procedure (20-23). Homologous blood recipients have significantly longer hospital stays attributed to treating infections. The cost of a blood transfusion exceeds the cost of collection, storage and administration because of transfusion's association with length of stay. In this era of cost-containment the association with prolonged stay may ultimately curtail the use of blood. Homologous blood can be filtered to remove donor leukocytes which may be contributing to immune suppression and infection risk. A prospective randomized trial comparing the infection rates among colorectal cancer patients receiving filtered and unfiltered blood has been conducted (9). There were 17 infectious complications among the 56 recipients of whole blood and one infectious complication among the 48 recipients of filtered blood. Infections were prevented by the seemingly simplistic addition of a $25/filter to every bag of blood transfused. These clinical studies are very convincing: homologous blood transfusion is associated with increased risk of infection in every clinical situation examined. In multivariate analyses transfusion was a significant predictor of infection after consideration of other variables measured and in the majority of those studies transfusion was the single most significant factor. Patients receiving homologous blood exhibited an incidence of infectious complications that was approximately four times higher than patients receiving autologous blood. The association of transfusion with infection is found among patients undergoing surgery for cardiac, orthopedic and gastrointestinal disorders and for trauma as well as among unoperated patients transfused for bums and gastrointestinal bleeding. The observation that nosocomial infections are increased in these studies argues strongly that the association of transfusion with infection is not simply a reflection of transfusion as a marker of tissue destruction and contamination. Infections that develop in transfused patients away from the site of trauma or in the absence of trauma, cannot be attributed to the quantity of tissue destroyed or to the degree of bacterial contamination. Filtered blood can remove leukocytes and prevent postoperative infections. Since filtering blood can significantly reduce the incidence of infection among transfused patients, all transfused blood will be passing through filters in the very near future. EXPERIMENTAL STUDIES RELATING BLOOD TRANSFUSION TO INCREASED RISK OF INFECTION Patients are extremely heterogeneous and even in prospective randomized trials, factors which influence patients' participation affect the outcome despite double-blinding and randomization. In animal studies using syngeneic strains with identical housing, lighting, access to food and water, control over the extent of injury, use of antibiotics and exposure to other variables the influence of a single variable such as blood transfusion can be measured. Dr. Waymack's laboratory has intensively studied parameters which interact with transfusion in

1995 ◽  
pp. 296-296

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