scholarly journals Photoperiod history-dependent responses to intermediate day lengths engage hypothalamic iodothyronine deiodinase type III mRNA expression

2013 ◽  
Vol 304 (8) ◽  
pp. R628-R635 ◽  
Author(s):  
August Kampf-Lassin ◽  
Brian J. Prendergast
Keyword(s):  
Mrna Expression ◽  
Gonadal Development ◽  
Day Length ◽  
Prior History ◽  
Dependent Manner ◽  
Iodothyronine Deiodinase ◽  
Siberian Hamsters ◽  
Neuroendocrine Mechanisms ◽  
History Of ◽  
Type 3

Perihypothalamic thyroid hormone signaling features prominently in the seasonal control of reproductive physiology. Triiodothyronine (T3) signaling stimulates gonadal development, and decrements in T3 signaling are associated with gonadal regression. Type 3 iodothyronine deiodinase (DIO3) converts the prohormone thyroxine (T4) into biologically inactive 3,3′,5′-triiodothyronine, and in long-day breeding Siberian hamsters exposure to long (LD) and short (SD) photoperiods, respectively, inhibit and stimulate hypothalamic dio3 mRNA expression. Reproductive responses to intermediate-duration photoperiods (IntD) occur in a history-dependent manner; IntDs are interpreted as inhibitory only when preceded by longer photoperiods. Because dio3 expression has only been evaluated under LD or SD photoperiods, it is not known whether hypothalamic dio3 encodes absolute photoperiod duration or the reproductive interpretation of photoperiod. Male Siberian hamsters with and without a prior history of LD were exposed to IntD photoperiods, and hypothalamic dio3 mRNA expression was measured 6 wk later. Hamsters with a LD photoperiod history exhibited gonadal regression in IntD and a marked upregulation of hypothalamic dio3 expression, whereas in hamsters without prior exposure to LD, gonadal responses to IntD were absent, and dio3 expression remained low. Patterns of deiodinase expression in hamsters maintained in chronic IntD photoperiods did not appear to reflect feedback effects of gonadal status. Hypothalamic expression of dio3 does not exclusively reflect ambient photoperiod, but rather the context-dependent reproductive interpretation of photoperiod. Neuroendocrine mechanisms that compare current and prior photoperiods, which permit detection of directional changes in day length, occur either upstream, or at the level, of hypothalamic dio3 expression.

Exogenous T3 mimics long day lengths in Siberian hamsters

2007 ◽  
Vol 292 (6) ◽  
pp. R2368-R2372 ◽  
Author(s):  
David A. Freeman ◽  
Brett J. W. Teubner ◽  
Carlesia D. Smith ◽  
Brian J. Prendergast
Keyword(s):  
Gonadal Development ◽  
Day Length ◽  
Intermediate Step ◽  
Iodothyronine Deiodinase ◽  
Short Day ◽  
Siberian Hamsters ◽  
Long Day ◽  
Long Duration ◽  
Reproductive Response

Siberian hamsters ( Phodopus sungorus) exhibit seasonal cycles of reproduction driven by changes in day length. Day length is encoded endogenously by the duration of nocturnal melatonin (Mel) secretion from the pineal gland. Short-duration Mel signals stimulate reproduction and long-duration signals inhibit reproduction. The mechanism by which Mel signals are decoded at the level of neural target tissues remains uncharacterized. In Siberian hamsters, exposure to short day lengths or injections of Mel in long days results in a decrease in hypothalamic expression of type 2 iodothyronine deiodinase (Dio2) mRNA. Dio2 catalyzes the conversion of the thyroid hormone thyroxine to triiodothyronine (T3). Thus exposure to short and long day lengths should decrease and increase hypothalamic T3 concentrations, respectively. We tested the hypothesis that exogenous T3 administered to short-day hamsters would mimic exposure to long day lengths with respect to gonadal stimulation. Hamsters gestated and raised in short day lengths that exhibited photoinhibition of the testes were given daily subutaneous injections of T3 or saline vehicle for 4 wk beginning at week 12 of life. The results indicate that exogenous T3 induced gonadal growth in short-day hamsters and delayed spontaneous gonadal development by an interval equal to the number of weeks during which T3 was administered. T3 injections delayed gonadal regression if given coincident with the transfer of hamsters from long to short day lengths. These results suggest that T3 mimics long day exposure in Siberian hamsters and may serve as an intermediate step between the Mel rhythm and the reproductive response.

scholarly journals Seasonal regulation of reproduction: altered role of melatonin under naturalistic conditions in hamsters

2010 ◽  
Vol 277 (1695) ◽  
pp. 2867-2874 ◽  
Author(s):  
Matthew P. Butler ◽  
Kevin W. Turner ◽  
Jin Ho Park ◽  
Elanor E. Schoomer ◽  
Irving Zucker ◽  
...  
Keyword(s):  
Body Weight ◽  
Day Length ◽  
Seasonal Transition ◽  
Siberian Hamsters ◽  
Long Day ◽  
Spring Equinox ◽  
Natural Photoperiod ◽  
History Of ◽  
Seasonal Regulation

The seasonal reproductive cycle of photoperiodic rodents is conceptualized as a series of discrete melatonin-dependent neuroendocrine transitions. Least understood is the springtime restoration of responsiveness to winter-like melatonin signals (breaking of refractoriness) that enables animals to once again respond appropriately to winter photoperiods the following year. This has been posited to require many weeks of long days based on studies employing static photoperiods instead of the annual pattern of continually changing photoperiods under which these mechanisms evolved. Maintaining Siberian hamsters under simulated natural photoperiods, we demonstrate that winter refractoriness is broken within six weeks after the spring equinox. We then test whether a history of natural photoperiod exposure can eliminate the requirement for long-day melatonin signalling. Hamsters pinealectomized at the spring equinox and challenged 10 weeks later with winter melatonin infusions exhibited gonadal regression, indicating that refractoriness was broken. A photostimulatory effect on body weight is first observed in the last four weeks of winter. Thus, the seasonal transition to the summer photosensitive phenotype is triggered prior to the equinox without exposure to long days and is thereafter melatonin-independent. Distinctions between photoperiodic and circannual seasonal organization erode with the incorporation in the laboratory of ecologically relevant day length conditions.

High Risk of One-year Stroke Recurrence in Patients with Younger Age and Prior History of Ischemic Stroke

2019 ◽  
Vol 16 (3) ◽  
pp. 250-257 ◽  
Author(s):  
Jiann-Der Lee ◽  
Ya-Han Hu ◽  
Meng Lee ◽  
Yen-Chu Huang ◽  
Ya-Wen Kuo ◽  
...  
Keyword(s):  
Logistic Regression ◽  
Ischemic Stroke ◽  
Multivariate Logistic Regression Analysis ◽  
Stroke Recurrence ◽  
Prior History ◽  
Multivariate Logistic Regression ◽  
Cart Analysis ◽  
Younger Age ◽  
History Of ◽  
One Year

Background and Purpose: Recurrent ischemic strokes increase the risk of disability and mortality. The role of conventional risk factors in recurrent strokes may change due to increased awareness of prevention strategies. The aim of this study was to explore the potential risk factors besides conventional ones which may help to affect the advances in future preventive concepts associated with one-year stroke recurrence (OSR). Methods: We analyzed 6,632 adult patients with ischemic stroke. Differences in clinical characteristics between patients with and without OSR were analyzed using multivariate logistic regression and classification and regression tree (CART) analyses. Results: Among the study population, 525 patients (7.9%) had OSR. Multivariate logistic regression analysis revealed that male sex (OR 1.243, 95% CI 1.025 – 1.506), age (OR 1.015, 95% CI 1.007 - 1.023), and a prior history of ischemic stroke (OR 1.331, 95% CI 1.096 – 1.615) were major factors associated with OSR. CART analysis further identified age and a prior history of ischemic stroke were important factors for OSR when classified the patients into three subgroups (with risks of OSR of 8.8%, 3.8%, and 12.5% for patients aged > 57.5 years, ≤ 57.5 years/with no prior history of ischemic stroke, and ≤ 57.5 years/with a prior history of ischemic stroke, respectively). Conclusions: Male sex, age, and a prior history of ischemic stroke could increase the risk of OSR by multivariate logistic regression analysis, and CART analysis further demonstrated that patients with a younger age (≤ 57.5 years) and a prior history of ischemic stroke had the highest risk of OSR.

Dysbaric osteonecrosis associated with decompression sickness in a fishing diver

2019 ◽  
pp. 217-220
Author(s):  
Eduardo Briceño-Souza ◽  
◽  
Nina Méndez-Domínguez ◽  
Ricardo j Cárdenas-Dajda ◽  
Walter Chin ◽  
...  
Keyword(s):  
Femoral Head ◽  
Decompression Sickness ◽  
Small Scale ◽  
Prior History ◽  
Radiological Findings ◽  
Small Scale Fisheries ◽  
Left Limb ◽  
History Of ◽  
Decompression Stress ◽  
Probable Diagnosis

Diving as a method of fishing is used worldwide in small-scale fisheries. However, one of the main causes of morbidity and mortality among fishermen is decompression sickness (DCS). We report the case of a 46-year-old male fisherman diver who presented with chronic inguinal pain that radiated to the lower left limb. Living and working in a fishing port in Yucatan, he had a prior history of DCS. A diagnosis of avascular necrosis in the left femoral head secondary to DCS was made via analysis of clinical and radiological findings. The necrosis was surgically resolved by a total hip arthroplasty. Dysbaric osteonecrosis is a more probable diagnosis. In this region fishermen undergo significant decompression stress in their daily fishing efforts. Further studies regarding prevalence of dysbaric osteonecrosis among small-scale fisheries divers are needed. In a community where DCS is endemic and has become an epidemic, as of late, the perception of this health risk remains low. Furthermore, training and decompression technique are lacking among the fishing communities.

Role of Cervical Cytology in Surveillance after a Radical Trachelectomy in Patients with a Prior History of Cervical Cancer

2016 ◽  
Vol 143 (1) ◽  
pp. 204-205
Author(s):  
J.S. Shah ◽  
A.J. Brown ◽  
N.D. Fleming ◽  
A.M. Nick ◽  
P.T. Soliman ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
Cervical Cytology ◽  
Prior History ◽  
Radical Trachelectomy ◽  
History Of

scholarly journals The association of triglyceride levels with the incidence of initial and recurrent acute pancreatitis

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Robert J. Sanchez ◽  
Wenzhen Ge ◽  
Wenhui Wei ◽  
Manish P. Ponda ◽  
Robert S. Rosenson
Keyword(s):  
Acute Pancreatitis ◽  
Medical Records ◽  
Adult Population ◽  
Baseline Period ◽  
Prior History ◽  
Inclusion Criteria ◽  
Exclusion Criteria ◽  
Recurrent Acute Pancreatitis ◽  
History Of ◽  
Nationally Representative

Abstract Background This retrospective cohort study assessed the annualized incidence rate (IR) of acute pancreatitis (AP) in a nationally representative US adult population, as well as the variation in the risk of AP events across strata of triglyceride (TG) levels. Methods Data were obtained from IQVIA’s US Ambulatory Electronic Medical Records (EMR) database linked with its LRxDx Open Claims database. Inclusion criteria included ≥1 serum TG value during the overlapping study period of the EMR and claims databases, ≥1 claim in the 12-month baseline period, and ≥ 1 claim in the 12 months post index. All TG measurements were assigned to the highest category reached: < 2.26, ≥2.26 to ≤5.65, > 5.65 to ≤9.94, > 9.94, and > 11.29 mmol/L (< 200, ≥200 to ≤500, > 500 to ≤880, > 880, and > 1000 mg/dL, respectively). The outcome of interest was AP, defined as a hospitalization event with AP as the principal diagnosis. Results In total, 7,119,195 patients met the inclusion/exclusion criteria, of whom 4158 (0.058%) had ≥1 AP events in the prior 12 months. Most patients (83%) had TGs < 2.26 mmol/L (< 200 mg/dL), while < 1% had TGs > 9.94 mmol/L (> 880 mg/dL). Overall, the IR of AP was low (0.08%; 95% confidence internal [CI], 0.08–0.08%), but increased with increasing TGs (0.08% in TGs < 2.26 mmol/L [< 200 mg/dL] to 1.21% in TGs > 11.29 mmol/L [> 1000 mg/dL]). In patients with a prior history of AP, the IR of AP increased dramatically; patients with ≥2 AP events at baseline had an IR of 29.98% (95% CI, 25.1–34.9%). Conclusion The risk of AP increases with increasing TG strata; however, the risk increases dramatically among patients with a recent history of AP.

scholarly journals Clozapine-induced stuttering in the absence of known risk factors: a case report

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Florence Jaguga
Keyword(s):  
Risk Factors ◽  
Family History ◽  
Side Effect ◽  
Case Reports ◽  
Extrapyramidal Symptoms ◽  
Prior History ◽  
Case Presentation ◽  
Rare Side Effect ◽  
History Of ◽  
Electrophysiological Findings

Abstract Background Stuttering is a rare side effect of clozapine. It has been shown to occur in the presence of one or more factors such as abnormal electrophysiological findings and seizures, extrapyramidal symptoms, brain pathology, and a family history of stuttering. Few case reports have documented the occurrence of clozapine-induced stuttering in the absence of these risk factors. Case presentation A 29-year-old African male on clozapine for treatment-resistant schizophrenia presented with stuttering at a dosage of 400 mg/day that resolved with dose reduction. Electroencephalogram findings were normal, and there was no clinical evidence of seizures. The patient had no prior history or family history of stuttering, had a normal neurological examination, and showed no signs of extrapyramidal symptoms. Conclusion Clinicians ought to be aware of stuttering as a side effect of clozapine, even in the absence of known risk factors. Further research should investigate the pathophysiology of clozapine-induced stuttering.

Loperamide Induced Recurrent Torsades de Pointes: A Case Report

2021 ◽  
pp. 089719002110048
Author(s):  
Gregory G. Jackson ◽  
Christine R. Lopez ◽  
Elizabeth S. Bermudez ◽  
Nina E. Hill ◽  
Dan M. Roden ◽  
...  
Keyword(s):  
Cardiac Arrest ◽  
Torsades De Pointes ◽  
Altered Mental Status ◽  
Spontaneous Circulation ◽  
Prior History ◽  
Common Phenomenon ◽  
Medical Providers ◽  
Return Of Spontaneous Circulation ◽  
History Of ◽  
Overdrive Pacing

Purpose: A case of loperamide-induced recurrent torsades de pointes is reported to raise awareness of an increasingly common phenomenon that could be encountered by medical providers during the current opioid epidemic. Summary: A 40 year-old-man with a prior history of opioid abuse who presented to the emergency department after taking up to 100 tablets of loperamide 2 mg daily for 5 years to blunt opioid withdrawal symptoms and was subsequently admitted to the intensive care unit for altered mental status and hyperthermia. The patient had prolonged QTc and 2 episodes of torsades de pointes (TdP) that resulted in cardiac arrest with return of spontaneous circulation. He was managed with isoproterenol, overdrive pacing, and methylnatrexone with no other events of TdP or cardiac arrest. Conclusion: A 40-year-old male who developed torsades de pointes from loperamide overdose effectively treated with overdrive pacing, isoproterenol, and methylnatrexone.

scholarly journals 570. “I don’t know”: The Typical Response When Taking Pneumococcal Immunization Histories in Kidney Transplant Candidates

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S349-S351
Author(s):  
Jahanavi M Ramakrishna ◽  
Tambi Jarmi ◽  
Claudia R Libertin
Keyword(s):  
Infectious Disease ◽  
Kidney Transplant ◽  
Pneumococcal Vaccine ◽  
Patient Population ◽  
Pneumococcal Vaccination ◽  
Prior History ◽  
Vaccine Preventable Diseases ◽  
Number Of Patients ◽  
Order Completion ◽  
History Of

Abstract Background Vaccine-preventable diseases account for significant morbidity and mortality in the kidney transplant (KT) patient population. AST Guidelines support review and documentation of pneumococcal vaccines in KT candidate infectious disease (ID) evaluations. The objective of this study is to determine the number of KT candidates screened for prior pneumococcal immunizations and the frequency of vaccines ordered by providers when indicated at Mayo Clinic Florida’s (MCF) Transplant Center. Methods This study was an institution-based retrospective analysis of all KT candidates evaluated at MCF from December 2, 2019 – January 14, 2020. Data collection was obtained by electronic health record review. Outcomes included known history and documentation rates of prior pneumococcal vaccinations (both Prevnar 13 and Pneumovax 23) by infectious disease (ID) providers, as well as pneumococcal vaccine order frequency during ID pre-transplant evaluation when indicated. Data analysis was done using simple descriptive statistics. Results Sixty-one patients underwent KT evaluation during the study period. Among the 61 patients, 20 (32.8%) and 20 (32.8%) had a known prior history of receiving Prevnar 13 and Pneumovax 23 vaccinations, respectively. Vaccine history was unknown for Prevnar 13 and Pneumovax 23 in 39 (63.9%) patients. Vaccine status was not documented by ID providers in 2 (3.3%) patients. When appropriate, ID providers ordered Prevnar 13 and Pneumovax 23 in 38 (92.7%) and 41 (100%) patients, respectively. Orders included both electronic and written documentation to account for patients planning immunization elsewhere. Of the 38 patients advised to receive the Prevnar 13 vaccine, 17 (41.5%) patients were documented completing immunization. Pneumovax 23 order completion rates were not recorded since the study period only lasted six weeks due to closure by COVID-19. Table 1. Pneumococcal Vaccine History Documentation Rates Obtained by Patient Recall or Records Table 2. Pneumococcal Vaccine Order Rates at Pre-Kidney Transplant Consultations Table 3. Prevnar 13 Order Completion Rate by Documentation Conclusion The data reflect a high number of patients who either do not recall or have documentation of prior pneumococcal vaccination available at time of KT ID evaluation. Providers documented history of pneumococcal vaccinations extremely well, ordering immunizations when necessary. This study highlights lack of portability of immunization histories in a given patient population and opportunity for improved care. Disclosures Claudia R. Libertin, MD, Pfizer, Inc. (Grant/Research Support, Research Grant or Support)

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