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Introduction: Interventional radiology (IR) is a technique for controlling hemorrhage and preserving fertility for women with serious obstetric conditions such as placenta accreta spectrum (PAS) or postpartum hemorrhage. This study examined maternal, pregnancy and hospital characteristics and outcomes for women receiving IR in pregnancy and postpartum., Material and Methods: A population-based record linkage study was conducted, including all women who gave birth in hospital in New South Wales or the major tertiary hospital in the neighboring Australian Capital Territory, Australia, between 2003 and 2019. Data were obtained from birth and hospital records. Characteristics and outcomes of women who underwent IR in pregnancy or postpartum are described. Outcomes following IR were compared in a high-risk cohort of women: those with PAS who had a planned cesarean with hysterectomy. Women were grouped by those who did and those who did did not have IR and were matched using propensity score and other factors., Results: We identified IR in 236 pregnancies of 1 584 708 (15.0 per 100 000), including 208 in the delivery and 26 in a postpartum admission. Two-thirds of women receiving IR in the birth admission received a transfusion of red cells or blood products, 28% underwent hysterectomy and 12.5% were readmitted within 6 weeks. Other complications included: severe maternal morbidity (29.8%), genitourinary tract trauma/repair (17.3%) and deep vein thrombosis/pulmonary embolism (4.3%). Outcomes for women with PAS who underwent planned cesarean with hysterectomy were similar for those who did and did not receive IR, with a small reduction in transfusion requirement for those who received IR., Conclusions: Interventional radiology is infrequently used in pregnant women. In our study it was performed at a limited number of hospitals, largely tertiary centers, with the level of adverse outcomes reflecting use in a high-risk population. For women with PAS undergoing planned cesarean with hysterectomy, most outcomes were similar for those receiving IR and those not receiving IR, but IR may reduce bleeding., (© 2023 The Authors. Acta Obstetricia et Gynecologica Scandinavica published by John Wiley & Sons Ltd on behalf of Nordic Federation of Societies of Obstetrics and Gynecology (NFOG).)

Purpose: Weight bias internalization (WBI) is associated with disordered eating symptomology and motivation to control weight. The relationship between WBI and specific weight control behaviours and how these behaviours differ between men and women is not well understood. The objectives of this study are to determine (1) the relationship between WBI and weight control behaviours, (2) whether weight perception is independently associated with weight control behaviours, and (3) whether these relationships differ between men and women., Methods: Canadian adults (N = 161; 52.8% women; body mass index [BMI] = 26.5 ± 4.99 kg/m 2 ) completed questionnaires pertaining to WBI, weight control behaviours (healthy, unhealthy, extreme) and weight perception (accurate, under-, or over-estimation compared with objectively measured BMI). The cross-sectional relationship between (1) WBI or (2) weight perception with the total number of healthy and unhealthy or extreme weight control behaviours, and likelihood of performing specific weight control behaviours were assessed with linear, and logistic regression models, respectively. All analyses were conducted adjusting for age, gender, and race. Subsequent analyses were stratified by sex., Results: WBI was associated with an increased likelihood of performing exercise for weight loss (OR 2.28, p < 0.05); increased likelihood of skipping meals in women (OR 2.57, p < 0.01), and consuming little amounts of food and food substitutes in men (OR 2.28, p < 0.01 and OR 2.17, p < 0.05, respectively). Weight perception was not associated with weight control behaviours., Conclusions: WBI was associated with various weight control behaviours. This study highlights the importance of assessing WBI in clinical practice with patients seeking to manage their weight. Future longitudinal research should be conducted to further understand the behavioural and health effects from WBI., Level V: Cross-sectional descriptive study., (© 2022. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Cells of unicellular and multicellular eukaryotes can respond to certain environmental cues by arresting the cell cycle and entering a reversible state of quiescence. Quiescent cells do not divide, but can re-enter the cell cycle and resume proliferation if exposed to some signals from the environment. Quiescent cells in mammals and humans include adult stem cells. These cells exhibit improved stress resistance and enhanced survival ability. In response to certain extrinsic signals, adult stem cells can self-renew by dividing asymmetrically. Such asymmetric divisions not only allow the maintenance of a population of quiescent cells, but also yield daughter progenitor cells. A multistep process of the controlled proliferation of these progenitor cells leads to the formation of one or more types of fully differentiated cells. An age-related decline in the ability of adult stem cells to balance quiescence maintenance and regulated proliferation has been implicated in many aging-associated diseases. In this review, we describe many traits shared by different types of quiescent adult stem cells. We discuss how these traits contribute to the quiescence, self-renewal, and proliferation of adult stem cells. We examine the cell-intrinsic mechanisms that allow establishing and sustaining the characteristic traits of adult stem cells, thereby regulating quiescence entry, maintenance, and exit., Competing Interests: The authors declare no conflict of interest.

The concentrations of some key metabolic intermediates play essential roles in regulating the longevity of the chronologically aging yeast Saccharomyces cerevisiae . These key metabolites are detected by certain ligand-specific protein sensors that respond to concentration changes of the key metabolites by altering the efficiencies of longevity-defining cellular processes. The concentrations of the key metabolites that affect yeast chronological aging are controlled spatially and temporally. Here, we analyze mechanisms through which the spatiotemporal dynamics of changes in the concentrations of the key metabolites influence yeast chronological lifespan. Our analysis indicates that a distinct set of metabolites can act as second messengers that define the pace of yeast chronological aging. Molecules that can operate both as intermediates of yeast metabolism and as second messengers of yeast chronological aging include reduced nicotinamide adenine dinucleotide phosphate (NADPH), glycerol, trehalose, hydrogen peroxide, amino acids, sphingolipids, spermidine, hydrogen sulfide, acetic acid, ethanol, free fatty acids, and diacylglycerol. We discuss several properties that these second messengers of yeast chronological aging have in common with second messengers of signal transduction. We outline how these second messengers of yeast chronological aging elicit changes in cell functionality and viability in response to changes in the nutrient, energy, stress, and proliferation status of the cell., Competing Interests: The authors declare no conflict of interest.

Purpose of Review: Little is known about the presence of parasomnias such as nightmare disorder, sleep paralysis, REM sleep behavior disorder (RBD), and sleep-related eating disorders (SRED) in people with mental illness. A predominant view suggests that psychotropic medications might be contributing to parasomnias. This article summarizes knowledge regarding the relationships between psychiatric disorders and parasomnias, and possible confounds. A systematic search of the literature in the past 10 years identified 19 articles., Recent Findings: There were significantly elevated rates of parasomnias in psychiatric disorders (average prevalence of nightmares was 38.9%, sleep paralysis 22.3%, SRED 9.9%, sleepwalking 8.5%, and RBD 3.8%). Medication usage was only one of many risk factors (other sleep disorders, medical comorbidities, and substance abuse) which were associated with parasomnias. A strong association exists between mental illness and parasomnias which is not fully explained by medications. Prospective longitudinal studies are needed to develop a better understanding of the unique and shared variance from multiple risk factors.

Phytochemicals are structurally diverse secondary metabolites synthesized by plants and also by non-pathogenic endophytic microorganisms living within plants. Phytochemicals help plants to survive environmental stresses, protect plants from microbial infections and environmental pollutants, provide them with a defense from herbivorous organisms and attract natural predators of such organisms, as well as lure pollinators and other symbiotes of these plants. In addition, many phytochemicals can extend longevity in heterotrophic organisms across phyla via evolutionarily conserved mechanisms. In this review, we discuss such mechanisms. We outline how structurally diverse phytochemicals modulate a complex network of signaling pathways that orchestrate a distinct set of longevity-defining cellular processes. This review also reflects on how the release of phytochemicals by plants into a natural ecosystem may create selective forces that drive the evolution of longevity regulation mechanisms in heterotrophic organisms inhabiting this ecosystem. We outline the most important unanswered questions and directions for future research in this vibrant and rapidly evolving field.

Mitochondrial functionality is vital to organismal physiology. A body of evidence supports the notion that an age-related progressive decline in mitochondrial function is a hallmark of cellular and organismal aging in evolutionarily distant eukaryotes. Studies of the baker's yeast Saccharomyces cerevisiae, a unicellular eukaryote, have led to discoveries of genes, signaling pathways and chemical compounds that modulate longevity-defining cellular processes in eukaryotic organisms across phyla. These studies have provided deep insights into mechanistic links that exist between different traits of mitochondrial functionality and cellular aging. The molecular mechanisms underlying the essential role of mitochondria as signaling organelles in yeast aging have begun to emerge. In this review, we discuss recent progress in understanding mechanisms by which different functional states of mitochondria define yeast longevity, outline the most important unanswered questions and suggest directions for future research.

Introduction. There are over 200 Cardiovascular Rehabilitation (CR) programs in Canada, providing services to more than 50,000 new patients annually. The objective of this study was to describe the impact of CR in Canada. Methods. A retrospective analysis of Canadian CR Registry data is presented. There were 12 programs participating, with 4546 CR participants. Results. The average wait time between patient referral and CR admission was 68 ± 64 days. Participants were 66.3 ± 11.5 years old, 71% male, and 82% White. The three leading referral events were coronary artery bypass graft surgery, percutaneous coronary intervention, and acute coronary syndrome. At discharge, data were available for ~90% of participants. Significant improvements in blood pressure (systolic pre-CR 123.5 ± 17.0, post-CR 121.5 ± 15.8 mmHg; p < .001), lipids, adiposity, and exercise capacity (peak METs pre-CR 6.5 ± 2.8, post-CR 7.2 ± 3.1; p < .001) were observed. However, target attainment for some risk factors was suboptimal. Conclusions. This report provides the first snapshot of the beneficial effects of CR in Canada. Not all patients are equally represented in these programs, however, leaving room for more referral of diverse patients. Greater attainment of risk reduction targets should be pursued.

Bile acids are cholesterol-derived bioactive lipids that play essential roles in the maintenance of a heathy lifespan. These amphipathic molecules with detergent-like properties display numerous beneficial effects on various longevity- and healthspan-promoting processes in evolutionarily distant organisms. Recent studies revealed that lithocholic bile acid not only causes a considerable lifespan extension in yeast, but also exhibits a substantial cytotoxic effect in cultured cancer cells derived from different tissues and organisms. The molecular and cellular mechanisms underlying the robust anti-aging and anti-tumor effects of lithocholic acid have emerged. This review summarizes the current knowledge of these mechanisms, outlines the most important unanswered questions and suggests directions for future research.

Rationale: Drug-associated environmental stimuli elicit craving in humans and drug-seeking in animals., Objectives: We tested the hypothesis that Pavlovian-conditioned alcohol-seeking is mediated by dopamine, using rats from two vendors., Methods: Male, Long-Evans rats (220-240 g) from Charles River (St-Constant, QC, Canada) and Harlan Laboratories (Indianapolis, IN, USA) received 21 sessions of intermittent, 24-h access to ethanol (15 %, v/v) and water in the home-cage. Subsequently, rats were trained to discriminate between one conditioned stimulus (CS+) that was paired with ethanol (0.2 ml per CS+) and a second stimulus (CS-) that was not. Entries into a fluid port where ethanol was delivered were recorded. Next, rats were exposed to a different context where cues and ethanol were withheld. At test, responding to the CS+ and CS- without ethanol was assessed in the second, non-alcohol context. Injections (1 ml/kg; s.c.) of the dopamine D1-receptor antagonist SCH 23390 (0, 3.33, and 10 μg/kg) or dopamine D2-receptor antagonist eticlopride (0, 5, and 10 μg/kg) were administered before test., Results: Home-cage alcohol consumption was higher in Harlan rats than Charles River rats. At test, saline-treated rats responded more to the alcohol-predictive CS+ than the CS-. While SCH 23390 attenuated CS+ responding in rats from both vendors, eticlopride reduced CS+ responding in Harlan rats only. Subsequently, SCH 23390 but not eticlopride attenuated CS+ responding when the CS+ was again paired with ethanol., Conclusions: These results indicate important differences in alcohol consumption in Long-Evans rats from different suppliers, and highlight a novel role for dopamine in Pavlovian-conditioned alcohol-seeking.

Metabolomic and lipidomic analyses of yeast cells provide comprehensive empirical datasets for unveiling mechanisms underlying complex biological processes. In this chapter, we describe detailed protocols for using such analyses to study the age-related dynamics of changes in intracellular and extracellular levels of various metabolites and membrane lipids in chronologically aging yeast. The protocols for the following high-throughput analyses are described: (1) microanalytic biochemical assays for monitoring intracellular concentrations of trehalose and glycogen; (2) gas chromatographic quantitative assessment of extracellular concentrations of ethanol and acetic acid; and (3) mass spectrometric identification and quantitation of the entire complement of cellular lipids. These protocols are applicable to the exploration of the metabolic patterns associated not only with aging but also with many other vital processes in yeast. The described here methodology complements the powerful genetic approaches available for mechanistic studies of fundamental aspects of yeast biology.

The essential role of the peroxisome in oxidizing fatty acids, maintaining reactive oxygen species homeostasis and replenishing tricarboxylic acid cycle intermediates is well known. Recent findings have broadened a spectrum of biomolecules that are synthesized and metabolized in peroxisomes. Emergent evidence supports the view that, by releasing various biomolecules known to modulate essential cellular processes, the peroxisome not only operates as an organizing platform for several developmental and differentiation programs but is also actively involved in defining the replicative and chronological age of a eukaryotic cell. The scope of this chapter is to summarize the evidence that the peroxisome defines yeast longevity by operating as a system controller that: (1) modulates levels of non-esterified fatty acids and diacylglycerol; (2) replenishes tricarboxylic acid cycle intermediates destined for mitochondria; and (3) contributes to the synthesis of polyamines. We critically evaluate molecular mechanisms underlying the essential role of peroxisomally produced and metabolized biomolecules in governing cellular aging in yeast.

The essential role of peroxisomes in fatty acid oxidation, anaplerotic metabolism, and hydrogen peroxide turnover is well established. Recent findings suggest that these and other related biochemical processes governed by the organelle may also play a critical role in regulating cellular aging. The goal of this review is to summarize and integrate into a model the evidence that peroxisome metabolism actually helps define the replicative and chronological age of a eukaryotic cell. In this model, peroxisomal reactive oxygen species (ROS) are seen as altering organelle biogenesis and function, and eliciting changes in the dynamic communication networks that exist between peroxisomes and other cellular compartments. At low levels, peroxisomal ROS activate an anti-aging program in the cell; at concentrations beyond a specific threshold, a pro-aging course is triggered., (© 2010 John Wiley & Sons A/S.)

The structure of a unique C,N-chelated dilithio dianion has been established as a solvated monomeric species using a combination of NMR and computational techniques. The highly ordered structure of the dianion may be important in its reactivity in an oxidative C-N bond-forming process.

Objective: To describe the use of telemedicine for setting goals for behavior change and examine the success in achieving these goals in rural underserved older adults with diabetes., Materials and Methods: Medicare beneficiaries with diabetes living in rural upstate New York who were enrolled in the telemedicine intervention of the Informatics for Diabetes Education and Telemedicine (IDEATel) project (n = 610) participated in home televisits with nurse and dietitian educators every 4-6 weeks for 2-6 years. Behavior change goals related to nutrition, physical activity, monitoring, diabetes health maintenance, and/or use of the home telemedicine unit were established at the conclusion of each televisit and assessed at the next visit., Results: Collaborative goal setting was employed during 18,355 televisits (mean of 33 goal-setting televisits/participant). The most common goals were related to monitoring, followed by diabetes health maintenance, nutrition, exercise, and use of the telemedicine equipment. Overall, 68% of behavioral goals were rated as "improved" or "met." The greatest success was achieved for goals related to proper insulin injection technique and daily foot care. These elderly participants had the most difficulty achieving goals related to use of the computer. No gender differences in goal achievement were observed., Conclusion: Televisits can be successfully used to collaboratively establish behavior change goals to help improve diabetes self-management in underserved elderly rural adults.

Growing evidence supports the view that LDs (lipid droplets) are dynamic organelles that can serve both as an intracellular signalling compartment and as an organizing platform orchestrating many vital processes in eukaryotic cells. It has become clear that the LDs-confined deposition and lipolytic degradation of neutral lipids define longevity in multicellular eukaryotic organisms and yeast. We summarize the evidence in support of the essential role that LDs play in longevity regulation and propose several molecular mechanisms by which these dynamic organellar compartments control the aging process in multicellular eukaryotes and yeast.

The formation of carbon-nitrogen (C-N) bonds is a fundamental bond construction in organic synthesis and is indispensable for the synthesis of alkaloid natural products. In the context of the synthesis of the architecturally complex Lycopodium alkaloid lyconadin A, we have discovered a highly efficient oxidative C-N bond forming reaction that relies on the union of a nitrogen anion and a carbon anion. Empirical evidence amassed during our synthetic studies suggests that the mechanism of the C-N bond forming process encompasses polar as well as radical processes. Herein, we present our study of this novel C-N bond forming reaction and its application to the enantioselective total synthesis of lyconadin A and related derivatives.

Total synthesis of the Lycopodium alkaloid lyconadin A was achieved in 18 steps starting from a readily available vinylogous ester and bromopicoline. The key step in the total synthesis is a proximity-driven oxidative C-N bond-forming reaction that yields the lyconadin pentacycle from a tetracyclic precursor. The key tetracycle, which has been prepared for the first time, is a versatile intermediate that may be utilized for the total synthesis of a variety of Lycopodium alkaloids. Critical to the success of this plan was the efficient preparation of a pyridine-annulated cycloheptadiene tricycle that promises to be a general strategy to access a variety of seven-membered ring containing natural products.

Biological membranes have unique and highly diverse compositions of their lipid constituents. At present, we have only partial understanding of how membrane lipids and lipid domains regulate the structural integrity and functionality of cellular organelles, maintain the unique molecular composition of each organellar membrane by orchestrating the intracellular trafficking of membrane-bound proteins and lipids, and control the steady-state levels of numerous signaling molecules generated in biological membranes. Similar to other organellar membranes, a single lipid bilayer enclosing the peroxisome, an organelle known for its essential role in lipid metabolism, has a unique lipid composition and organizes some of its lipid and protein components into distinctive assemblies. This review highlights recent advances in our knowledge of how lipids and lipid domains of the peroxisomal membrane regulate the processes of peroxisome assembly and maintenance in the yeast Yarrowia lipolytica. We critically evaluate the molecular mechanisms through which lipid constituents of the peroxisomal membrane control these multistep processes and outline directions for future research in this field.

The peroxisome has long been known for its role in lipid metabolism and hydrogen peroxide detoxification. However, growing evidence supports the view that this organelle can also function both as an intracellular signaling compartment and as an organizing platform that orchestrates certain developmental decisions from inside the cell. This review highlights various strategies that peroxisomes employ to regulate the processes of development, differentiation, and morphogenesis and critically evaluates several molecular mechanisms by which peroxisomes promote these processes.

Malignant hyperthermia (MH) is a potentially lethal disorder triggered in susceptible individuals on exposure to common anaesthetic agents. Crises reflect the consequences of disturbed skeletal muscle calcium homeostasis. MH is an autosomal dominant, genetically heterogeneous trait. Defects in a single major gene have been assumed to determine susceptibility status in individual families. However, in some pedigrees phenotypic and genotypic data are discordant. One explanation, in contrast to the current genetic model, is that susceptibility is dependent upon the effects of more than one gene. Using the transmission disequilibrium test we assessed the involvement of 8 MH candidate loci (RYR1, CACNA1S, CACNA2D1, MHS4 at 3q13.1, MHS6 at 5p, LIPE, DM1, dystrophin) by analysis of data from 130 MH nuclear families. Results suggested that variations in more than one gene may influence MH susceptibility in single families.

Malignant hyperthermia (MH) is an autosomal dominant disorder presenting under general anaesthesia. It is occasionally associated with a myopathy, central core disease (CCD), named after its predominant histochemical characteristic. The penetration of CCD is variable, but typically affected individuals show delayed motor milestones in infancy and remain physically compromised. It was thought until recently that individuals with CCD were always susceptible to MH. Individuals from eight CCD families were screened for the presence of 13 mutations in the skeletal muscle ryanodine receptor gene, reported previously to be associated with MH and/or CCD: none was detected. In seven of these families, where CCD and MH co-existed, we examined the segregation of CCD, MH susceptibility and chromosome 19q markers. In four families, there was complete co-segregation between MH, CCD and the chromosome 19 markers, but in one large pedigree there was a clear lack of segregation of CCD with either MH or chromosome 19 markers and there was no segregation between MH and these markers. This is unequivocal evidence that CCD, in common with MH, is genetically heterogeneous. In the two other families, CCD segregated with chromosome 19 markers but not all individuals with CCD were susceptible to MH. We recommend determination of MH susceptibility in all patients with CCD, irrespective of the MH status of their relatives with CCD.

Malignant hyperthermia (MH) is an autosomal dominant genetic condition that presents in susceptible people undergoing general anaesthesia. The clinical disorder is a major cause of anaesthetic morbidity and mortality. The UK Malignant Hyperthermia Group has performed genetic linkage analysis on 20 large, well defined malignant hyperthermia families, using hypervariable markers on chromosome 19q13.1, including the candidate MH gene RYR1, the gene coding for the skeletal muscle ryanodine receptor protein. The results were analysed using LINKAGE to perform two point and multipoint lod scores, then HOMOG to calculate levels of heterogeneity. The results clearly showed genetic heterogeneity between MH families; nine of the families gave results entirely consistent with linkage to the region around RYR1 while the same region was clearly excluded in three families. In the remaining eight MHS families there were single recombinant events between RYR1 and MH susceptibility. HOMOG analysis was of little added benefit in determining the likelihood of linkage to RYR1 in these families. This confirmation of the presence of heterogeneity in the UK MH population, along with the possibility of the presence of two MH genes in some pedigrees, indicates that it would be premature and potentially dangerous to offer diagnosis of MH by DNA based methods at this time.

A single base change in the RYR1 gene encoding the skeletal muscle ryanodine receptor (calcium-sensitive calcium-release channel of the sarcoplasmic reticulum), resulting in the substitution of G1021 by A, has been proposed to underlie malignant-hyperthermia (MH) susceptibility in as many as 10% of cases in the European population. As part of our mutation-screening program in MH-susceptible (MHS) individuals, we have investigated this substitution in individuals from 151 unrelated British MHS families and have detected G1021A heterozygotes in 7 families. This mutation was not found in 156 unrelated MH-negative (MHN) individuals. We also examined eight families with central core disease (CCD): the mutation did not occur in any family members of any disease status (affected or unaffected for CCD, MHS, or MHN). In one large family, the G1021A mutation was found but did not show complete cosegregation with MH susceptibility: it occurred in only 7/12 MHS individuals in the kinship, and susceptibility was inherited from parents who were G1021 homozygotes, as well as from parents who were heterozygotes. On the basis of these findings, it is clearly unreliable at present to offer presymptomatic DNA testing for MH status, even in families in which a mutation has been detected.

Mutations in the APC gene are responsible for the dominantly inherited colon cancer syndrome, familial adenomatous polyposis (FAP). We have designed PCR primers which allow amplification by RT-PCR of exons 1-14 of the APC gene in six overlapping segments. The amplicons have been screened for the presence of mutations in patients affected with FAP using heteroduplex analysis. One patient has been identified with an alternatively spliced transcript involving exon 14 and a single base insertion mutation within the same exon.

Production of embryos that are free of tough outer coats facilitates studies that are not possible with embryos surrounded by impenetrable envelopes. This report describes a new procedure for preventing formation of fertilisation membranes in the sea urchin (Lytechinus pictus) model. This procedure involves treating unfertilised eggs with the enzyme alpha-amylase, which cleaves alpha-1,4 glucosidic bonds in the vitelline layer. A major advantage of this method is that it is very well defined and completely controllable with alpha-amylase inhibitor. The results suggest that intact alpha-1,4 glucosidic bonds are essential for vitelline layer integrity required for formation of the fertilisation membrane. Eggs treated with alpha-amylase possessed the same surface lectin receptors as untreated eggs and, as shown by light and transmission electron microscopy, produced healthy, cleaving embryos that were free of fertilisation envelopes.

Interleukin-4 is a member of the cytokine family, a group of related messenger proteins which collectively help to moderate and control the immune response. It is believed that the folding topology of the beta-sheets of the interleukin-4 receptor (IL4R) is the same as that seen in the crystal structure of CD4. Although the sequence identity is low, homology modeling techniques have been used to model the IL4R structure from CD4. Refinement by molecular dynamics leads to a suggested structure which has been docked to interleukin-4 (IL4). Several residues of apparent importance for binding are identified.

The soleus atrophies rapidly when a rat is subjected to hindlimb suspension (HS), probably as a result of a decrease in the force encountered by the muscle. To test this premise, adult female rats were HS and half the rats were exercised (HS-EX) on a treadmill for 1.5 h.d-1 at 20 m.min-1 and a 30% grade. After 4 weeks, the midbelly of the soleus was prepared for histochemical analysis. Fibers were typed as dark or light staining for myosin ATPase, alkaline preincubation. Fiber size and quantitative histochemical enzyme activities of succinate dehydrogenase (SDH) were determined using a computer enhanced image processing system. In comparison to age-matched controls, the soleus wet weight was 69 and 30% smaller in HS and HS-EX rats. The mean cross sectional area of the dark ATPase fibers was reduced by 46 and 18% and light ATPase fibers by 69 and 48% in the HS and HS-EX, respectively. The percent dark ATPase fibers increased from 10% in the control rats to 19 and 17% in the HS and HS-EX. In both suspended groups, SDH activities in light ATPase fibers were 40% higher than control. The SDH activity of the dark ATPase fibers of HS-EX was 20% higher than control, while the dark ATPase fibers of HS were similar to control. To determine the degree to which these increases in SDH could be related to reductions in fiber size rather than increases in the actual amount of protein, integrated activity (activity/min x area) was calculated per fiber.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of low thoracic spinal transection on muscle weights, fiber type distributions, and fiber cross-sectional areas (CSAs) of selected cat hind limb mixed-fast flexors and extensors and slow extensors were studied. Cats were spinalized at T12 at 2 weeks of age and maintained for 6 to 12 months. In general spinalization resulted in a decrease in muscle weights of extensors, while the weights of those muscles that function as either flexors or as both flexors and extensors were maintained. The percentages of fast-twitch [fast glycolytic (FG) and fast oxidative-glycolytic (FOG)] fibers increased and slow oxidative (SO) fibers decreased as a result of spinalization. However, FG fibers had a smaller CSA after spinal transection in both extensors and flexors. The total relative CSA of FG fibers per whole muscle was similar in spinalized and control cats. The relative muscle CSA occupied by SO fibers decreased in extensors and flexors as a result of a lower proportion of SO fibers and/or smaller SO fibers in spinalized cats. These findings suggest that muscles become more "fast-like" histochemically while little change occurs in the oxidative staining properties in either extensors or flexors in 6- to 12-month-old cats transected at 2 weeks of age. Further, these data suggest that the amount of muscle atrophy that occurs as a result of spinal transection is not closely related to the percentage reduction in SO fibers.