Associations between psychological distress in adolescence and menstrual symptoms across life: Longitudinal evidence from the 1970 British Cohort Study

PURPOSE

This study aimed to investigate the association between psychological distress (PD) at age 16 and menstrual symptoms experienced across women's life.

METHODS

Up to 2584 females from the 1970 British Cohort Study, a study of individuals born within one week in 1970, were included. PD at age 16 was measured with the 12-item General Health Questionnaire. Three categories were derived: low PD (<11), moderate PD (11-15), and severe PD (>15). Five menstrual health symptoms were self-reported at each age (16, 30 and 42 years). Binomial logistic regressions examined associations between PD at age 16 and each individual symptom, adjusted for age of menarche, sleep and appetite problems, physical activity levels and socioeconomic position.

RESULTS

The most prevalent symptoms were "pain" (61 %), "painful period" (10 %) and "heavy period" (33 %) at ages 16, 30 and 42, respectively. At age 16, those with severe PD were more likely to experience depression (OR: 2.92; 95% CI: 2.31, 3.70)), irritability (1.67; 1.33, 2.11), menstrual pain (1.34; 1.01, 1.80), and headaches (1.29; 1.02, 1.63). A weak association was found between severe PD at age 16 and pre-menstrual tension at age 30 (1.72; 1.01, 2.83). At age 42, those with severe PD at age 16 were more likely to experience pre-menstrual tension (1.89; 1.46, 2.44), painful periods (1.64; 1.27, 2.11), and heavy periods (1.28; 1.00, 1.62).

DISCUSSION

Menstruating females with higher levels of PD in adolescence have an increased risk of menstrual symptoms across adolescence, early and mid-adulthood. Our findings suggest the need to consider early-life psychological interventions to improve women's menstrual experiences across their reproductive years.

Is cardiorespiratory fitness associated with cognitive outcomes in mid-adulthood? Findings from the 1958 British birth cohort

Identifying causal factors to intervene on to delay age-related declines in cognitive function is urgently needed. We examined associations between non-exercise testing cardiorespiratory fitness (NETCRF; estimated using sex, age, body mass index, resting heart rate, and physical activity) at 45 years and cognitive function outcomes (immediate and delayed verbal memory; verbal fluency; visual processing speed) at 50 years in 8130 participants from the 1958 British birth cohort. In unadjusted models, higher NETCRF was associated with better cognitive function across all outcomes. When adjusted for confounding factors, associations disappeared. In this cohort, associations between 45 years NETCRF and 50 years cognitive function likely result from confounding factors.

Associations between sporting physical activity and cognition in mid and later-life: Evidence from two cohorts

Evidence has linked sporting leisure time physical activity (sporting-LTPA) to healthy cognition throughout adulthood. This may be due to the physiological effects of physical activity (PA), or to other, psychosocial facets of sport. We examined associations between sporting-LTPA and cognition while adjusting for device-measured PA volume devoid of context, both in midlife (N = 4041) participants from the 1970 British Cohort Study and later-life (N = 957) participants from the British Regional Heart Study. Independent of device-measured PA, we identified positive associations between sporting-LTPA and cognition. Sports with team/partner elements were strongly positively associated with cognition, suggesting LTPA context may be critical to this relationship.

Associations between the composition of daily time spent in physical activity, sedentary behaviour and sleep and risk of depression: Compositional data analyses of the 1970 British cohort Study

BACKGROUND

The benefits of moderate to vigorous physical activity(MVPA) in lowering depression risk are well established, but there is mixed evidence on sleep, sedentary behaviour(SB), and light-intensity physical activity(LIPA). These behaviours are often considered in isolation, neglecting their behavioural and biological interdependences. We investigated how time spent in one behaviour relative to others was associated with depression risk.

METHODS

We included 4738 individuals from the 1970 British Cohort study (age 46 wave). Depression status was ascertained using self-reported doctor visits and prescribed anti-depressant use. MVPA, LIPA, SB and sleep were ascertained using thigh-worn accelerometers worn consecutively for 7 days. Compositional logistic regression was used to examine associations between different compositions of time spent in movement behaviours and depression.

RESULTS

More time spent in MVPA, relative to SB, sleep or LIPA, was associated with a lower risk of depression. When modelling reallocation of time (e.g. replacing time in one behaviour with another), replacing sleep, SB or LIPA with MVPA time was strongly associated with lower depression risk. Reallocating time between SB, sleep or LIPA had minimal to no effect.

LIMITATIONS

Data was cross-sectional, therefore causality cannot be inferred. Accelerometers do not capture SB context (e.g. TV watching, reading) nor separate biological sleep from time spent in bed.

CONCLUSIONS

Displacing any behaviour with MVPA was associated with a lower risk of depression. This study provides promising support that increasing MVPA, even in small doses, can have a positive impact on prevention, mitigation and treatment of depression.

Alignment and scaling of large-scale fluctuations in the solar wind

We investigate the dependence of solar wind fluctuations measured by the Wind spacecraft on scale and on the degree of alignment between oppositely directed Elsasser fields. This alignment controls the strength of the nonlinear interactions and, therefore, the turbulence. We find that at scales larger than the outer scale of the turbulence the Elsasser fluctuations become on average more antialigned as the outer scale is approached from above. Conditioning structure functions using the alignment angle reveals turbulent scaling of unaligned fluctuations at scales previously believed to lie outside the turbulent cascade in the "1/f range." We argue that the 1/f range contains a mixture of a noninteracting antialigned population of Alfvén waves and magnetic force-free structures plus a subdominant population of unaligned cascading turbulent fluctuations.

Overexpression of NGF ameliorates ethanol neurotoxicity in the developing cerebellum

Transgenic mice overexpressing NGF in the central nervous system under the control of the glial fibrillary acidic protein (GFAP) promoter were exposed to ethanol via vapor inhalation on postnatal days 4 and 5 (P4-5), the period of maximal cerebellar Purkinje cell sensitivity to ethanol. Wild-type controls were exposed in a similar manner. There were no differences in body weight or size following these procedures, but the transgenic brain weights at this age were significantly greater than wild-type controls. In the wild-type animals, a significant 33.3% ethanol-mediated loss of Purkinje cells in lobule I was detected via unbiased three-dimensional stereological counting on P5. In the GFAP-NGF transgenic animals, however, the 17.6% difference in Purkinje cell number in control and ethanol-exposed animals was not significant. There was a similar difference in Purkinje cell density in both groups, which did reach statistical significance (-32.7% in wild-type ethanol-treated animals, -17% in transgenic ethanol-exposed animals). These results suggest that endogenous overexpression of neurotrophic factors, which have previously been shown to protect against ethanol neurotoxicity in culture, can serve a similar protective function in the intact animal.

BDNF and NGF afford in vitro neuroprotection against ethanol combined with acute ischemia and chronic hypoglycemia

Consumption of alcohol during pregnancy can result in central nervous system deficits in infants ranging from fetal alcohol effects to fetal alcohol syndrome. Changes in cerebral metabolism causing ischemic in utero conditions can also result from ethanol (EtOH). Growth factors have been shown to ameliorate ischemic damage and EtOH-induced neurotoxicity. However, using an in vitro model system of fetal alcohol effects/fetal alcohol syndrome, this study examines the neuroprotective effects of nerve growth factor, brain-derived neurotrophic factor, or glial cell line derived neurotrophic factor against EtOH treatment (0, 200, 400, 800, or 1, 600 mg/dl) combined with acute ischemia (2-hour hypoxia in EtOH-containing glucose-free media) followed by chronic hypoglycemia (16-hour glucose deprivation in EtOH-containing media). 3-(4, 5-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assays assessed relative neurotoxicity. Glial cell derived neurotrophic factor was not neuroprotective. Nerve growth factor protected against ischemia/hypoglycemia combined with 0-1,600 mg/dl EtOH. Brain-derived neurotrophic factor protected against ischemia/hypoglycemia combined with 0-800 mg/dl EtOH. These studies demonstrate marked growth factor neuroprotection against a myriad of conditions encountered by developing EtOH-exposed fetuses.

Ethanol-induced alterations in the expression of neurotrophic factors in the developing rat central nervous system

Neonatal rats were exposed to ethanol throughout gestation, or during the early postnatal period (postnatal days 4-10 (P4-10)), and enzyme-linked immunoabsorbent assays were subsequently conducted in order to assess nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) protein content in hippocampus, septum, cortex/striatum and cerebellum. These determinations revealed that following prenatal ethanol treatment, there were significant ethanol-induced increases in NGF in P1 cortex/striatum, but no changes in any of the three neurotrophic factors (NTFs) in the other brain regions. Cortex/striatal NGF protein returned to control levels by P10. Following early postnatal exposure, BDNF was elevated in hippocampus and cortex/striatum (assessed on P10), and NGF was also enhanced in cortex/striatum at this age. Hippocampal and cortex/striatal BDNF returned to control levels by P21, but cortex/striatal NGF levels remained enhanced at this age. This NTF did not differ in ethanol and control animals by P60, however. The possible significance of elevated levels of NTFs as a function of ethanol exposure is discussed, and it is speculated that while such alterations could play a protective role, increases in these substances during critical developmental periods could also prove to be deleterious, and could even contribute to certain of the neuropathologies which have been observed following developmental ethanol exposure.

Effect of neonatal ethanol exposure on parvalbumin-expressing GABAergic neurons of the rat medial septum and cingulate cortex

This study was performed to determine the long-term effects of ethanol exposure during the brain growth spurt (postnatal days 4-10) on the number of parvalbumin-immunoreactive (PA+) GABAergic neurons in the adult (P60) rat medial septum and anterior cingulate cortex. Significant loss of neurons within each of these populations has previously been demonstrated following prenatal ethanol exposure. In the present study, no significant differences in the number of PA+ neurons were found in either the medial septum or the cingulate cortex when control and ethanol-exposed animals were compared. The cellular densities and volumetric measures in both brain regions were also similar in the two groups. We speculate that compensatory up-regulative mechanisms may have accounted for the protection of the PA neuronal populations in these two areas following the early neonatal exposure.

Amelioration of ethanol-induced neurotoxicity in the neonatal rat central nervous system by antioxidant therapy

BACKGROUND

The cerebellum of the neonatal rat is highly susceptible to ethanol, with profound loss of Purkinje cells resulting from even brief exposure during the first postnatal week. Developmental ethanol exposure previously has been shown to induce free radicals/oxidative stress processes and/or down-regulate protective antioxidants. In an earlier study, we found antioxidants protected against ethanol neurotoxicity in a tissue culture environment. The present study was designed to determine whether similar protection could be manifested in the intact animal.

METHODS

Neonatal rats were administered a liquid diet via intragastric intubation on postnatal days 4 and 5 (P4-P5), the peak period of ethanol sensitivity in the developing cerebellum. The diet consisted of milk formula with 12% ethanol, the isocaloric substitution of maltose-dextrin for ethanol, or ethanol plus the antioxidant vitamin E. Unbiased three-dimensional counting was utilized to analyze Purkinje cell numbers and density within defined volumes from these animals on P5.

RESULTS

These determinations revealed a substantial loss of Purkinje cells in the ethanol-treated animals compared to controls (approximately 30-44%), but this loss was prevented by the inclusion of vitamin E (601U/100 ml) in the diet. A lower concentration of the antioxidant (301U/100 ml) was not effective in this regard, however.

CONCLUSIONS

These results suggest that ethanol-related cerebellar damage during this early postnatal period may be related to oxidative stress processes or the insufficiency of protective antioxidants. Thus, antioxidant treatment may represent a possible therapy for preventing or ameliorating the central nervous system (CNS) damage seen in the fetal alcohol syndrome.

Ethanol-induced alterations in neurotrophin expression in developing cerebellum: relationship to periods of temporal susceptibility

BACKGROUND

The developing cerebellum has been shown to be profoundly affected by exposure to ethanol and to exhibit a temporal pattern of vulnerability. Cerebellar Purkinje cells are particularly susceptible to ethanol on postnatal day 4 or day 5 (P4-5), whereas this population is much less vulnerable to similar ethanol insult slightly later in the postnatal period (P7-9). The purpose of the study was to determine whether differential alterations in neurotrophic factors might be associated with this differential susceptibility.

METHODS

Neonatal rats were exposed to ethanol via vapor inhalation, and enzyme-linked immunoabsorbent assays were subsequently conducted to assess cerebellar nerve growth factor, brain-derived neurotrophic factor, and neurotrophin-3 protein content. These analyses were made after ethanol exposure during the period of maximal cerebellar ethanol sensitivity (postnatal days 4-5 [P4-51), during a period of much lower sensitivity (P7-8), and during the entire "brain growth spurt" (P4-10).

RESULTS

These determinations revealed a significant ethanol-induced decrease in cerebellar nerve growth factor after exposure on P4-5 but not after exposure on P7-8 or P4-10. No significant changes in brain-derived neurotrophic factor or neurotrophin-3 were found with any of the exposure paradigms.

CONCLUSIONS

These results suggest that alterations in nerve growth factor, which has previously been shown to support cerebellar Purkinje and granule cells, may be a mechanism contributing to the early ethanol susceptibility within these neuronar populations.

Insulin-induced insulin receptor substrate-1 degradation is mediated by the proteasome degradation pathway

Insulin receptor substrate (IRS) proteins are important intracellular molecules that mediate insulin receptor tyrosine kinase signaling. A decreased content of IRS proteins has been found in insulin-resistant states in animals, humans, and cultured cells under various conditions. However, the molecular mechanism that controls cellular levels of IRS proteins is unknown. We report that chronic insulin treatment induces the degradation of IRS-1, but not IRS-2, protein in cultured cells. The insulin-induced degradation of IRS-1 can be prevented by pretreatment with lactacystin, a specific inhibitor for proteasome degradation. These data demonstrate, for the first time, that insulin-induced degradation of IRS-1 is mediated by the proteasome degradation pathway. IRS-2 can escape from the insulin-induced proteasome degradation, suggesting the existence of specific structural requirements for this degradation process.

TNF-alpha and insulin, alone and synergistically, induce plasminogen activator inhibitor-1 expression in adipocytes

Obesity is associated with hyperinsulinemia and elevated concentrations of tumor necrosis factor-alpha (TNF-alpha) in adipose tissue. TNF-alpha has been implicated as an inducer of the synthesis of plasminogen activator inhibitor-1 (PAI-1), the primary physiological inhibitor of fibrinolysis, mediated by plasminogen activators in cultured adipocytes. To identify mechanism(s) through which TNF-alpha induces PAI-1, 3T3-L1 preadipocytes were differentiated into adipocytes and exposed to TNF-alpha for 24 h. TNF-alpha selectively increased the synthesis of PAI-1 without increasing activity of plasminogen activators. Both superoxide (generated by xanthine oxidase plus hypoxanthine) and hydrogen peroxide were potent inducers of PAI-1, and hydroxyl radical scavengers completely abolished the TNF-alpha induction of PAI-1. Exposure of adipocytes to TNF-alpha or insulin alone over 5 days increased PAI-1 production. These agonists exert synergistic effects. Results obtained suggest that TNF-alpha stimulates PAI-1 production by adipocytes, an effect potentiated by insulin, and that adipocyte generation of reactive oxygen centered radicals mediates the induction of PAI-1 production by TNF-alpha. Because induction of PAI-1 by TNF-alpha is potentiated synergistically by insulin, both agonists appear likely to contribute to the impairment of fibrinolytic system capacity typical in obese, hyperinsulinemic patients.

Vitamin E and beta-carotene protect against ethanol combined with ischemia in an embryonic rat hippocampal culture model of fetal alcohol syndrome

Neurodevelopmental damage can occur as a result of in utero exposure to alcohol. Oxidative stress processes are one of many proposed mechanisms thought to contribute to nervous system dysfunction characterized in fetal alcohol syndrome (FAS). Therefore, this study examined neuroprotective effects of antioxidant supplementation during ethanol (EtOH) treatment (0, 200, 400, 800 or 1600 mg/dl) combined with concomitants of EtOH exposure: acute (2-h) ischemia (aISCH) and chronic (16-h) hypoglycemia (cHG). The antioxidants vitamin E and beta-carotene protected embryonic hippocampal cultures against 0-1600 mg/dl EtOH/aISCH/cHG treatments. In addition, neuronal viability, as measured by MTT ((3,4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide; 5 mg/ml)), was equal to untreated cultures when supplemented with vitamin E or beta-carotene at 0-800 mg/dl or 0-200 mg/dl EtOH/aISCH/cHG, respectively. These in vitro studies mirror potential in utero ethanol-exposed CNS conditions and may lead to therapeutic strategies targeted at attenuating neurodevelopmental FAS-related deficits.

The antioxidants vitamin E and beta-carotene protect against ethanol-induced neurotoxicity in embryonic rat hippocampal cultures

Fetal alcohol syndrome is characterized by numerous nervous system anomalies with the developing hippocampus being highly vulnerable. Other conditions can result from maternal ethanol consumption including oxidative stress. Critical antioxidants, such as vitamin E, can be decreased and antioxidative defenses altered. Gestational day 18 rat hippocampal cultures were exposed to ethanol ranging from 400 to 2400 mg/dl (16 h). MTT assays assessed neurotoxicity. Viability was decreased dose dependently. Supplementation with vitamin E or beta-carotene afforded neuroprotection against all ethanol concentrations. Vitamin E completely ameliorated neuronal loss following 400 and 800 mg/dl ethanol. Vitamin E increased survival to 95%, 79%, 66%, and 75% during 1600, 1800, and 2000 and 2400 mg/dl ethanol compared to nonethanol treatment. Vitamin E increased viability by 38%, 23%, 12%, and 29% at 1600, 1800, 2000, and 2400 mg/dl compared to non-vitamin E-supplemented, ethanol treatment. beta-Carotene completely ameliorated cell loss from 400 mg/dl ethanol and increased survival by 18% at 1600 mg/dl and 12% at 2000 mg/dl. This study demonstrates in vitro antioxidative neuroprotection against developmental ethanol exposure and suggests that nutritional therapies incorporating antioxidants may help protect against deleterious fetal effects from maternal alcohol abuse.

Myofibroblasts in diffuse alveolar damage of the lung

The myofibroblast is an ultrastructurally and metabolically distinctive connective tissue cell identified as a key participant in tissue remodeling in human granulation tissue, organ fibrosis, and the fibroblastic host response to malignant neoplasms. In this study of myofibroblasts in human lung diffuse alveolar damage (DAD), we identified 36 autopsy cases in which DAD could be histologically documented. DAD is known to progress from initial injury through an exudative, proliferative, and terminal fibrotic phase. In the exudative phase (16 cases), myofibroblasts expressing alpha-smooth muscle actin (alpha-SMA) are found in the septa and less frequently in hyaline membranes. In the proliferative phase (18 cases), many myofibroblasts in septa, hyaline membranes, and intra-alveolar fibroplasia express alpha-SMA. The alpha-SMA phenotype should be used in additional studies of myofibroblast differentiation, replication, and apoptosis. A better understanding of the biology of this cell type should offer new therapy for patients with DAD.

Age-related changes in [3H]MK-801 binding in the Fischer 344 rat brain

In this study we tested the hypothesis that the efficacy of L-glutamate to stimulate [3H]MK-801 binding to the NMDA receptor/channel complex is altered as a function of aging. L-Glutamate, or related excitatory amino acid (EAA), is the endogenous neurotransmitter of the NMDA receptor/channel complex. These studies examined the efficacy and potency with which L-glutamate produces receptor activation, channel opening and subsequent MK-801 binding as a function of increasing age by comparing dose-response curves (EC50 and Emax) from 6-, 12-, and 24-month-old F-344 rats. The number of NMDA receptors, as determined by [3H]MK-801 binding in the presence of a saturating concentration of L-glutamate, was reduced in the inner frontal cortex, entorhinal cortex and the lateral striatum in aged rats when compared with young adults. When a range of L-glutamate concentrations were used, differences in Emax were noted in the same brain regions in addition to several others in aged and middle-aged animals when compared with young-adult animals. No changes in EC50 values were noted in any of the brain regions at either age when compared with young-adults.

A comparative study of ethanol, hypoglycemia, hypoxia and neurotrophic factor interactions with fetal rat hippocampal neurons: a multi-factor in vitro model developmental ethanol effects

Fetal alcohol syndrome (FAS) is characterized by numerous central nervous system anomalies, with the hippocampus being particularly vulnerable to developmental ethanol exposure. In addition to direct ethanol neurotoxicity, other conditions resulting from maternal ethanol consumption, such as hypoglycemia and hypoxia, may also contribute to FAS. The present study used a tissue culture system to model multiple conditions which may relate to in vivo FAS, and assessed their relative neurotoxicity with MTT assays. Gestational day 18 rat hippocampal cultures were exposed to varying ethanol concentrations, glucose withdrawal-induced hypoglycemic (gwHG, 16 h) or acute hypoxic (aHP, 2 h) conditions alone, as well as to co-treatments with ethanol and gwHG or aHP. Brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) have previously been shown to ameliorate ethanol-, hypoglycemia- and hypoxia-induced neurotoxicity. Therefore, their neuroprotective potential, along with ciliary neurotrophic factor (CNTF), was examined. Neuronal viability was reduced dose-dependently by ethanol, alone or with hypoglycemia or hypoxia. Ethanol + gwHG or aHP was not uniformly additive. NGF treatment provided the most extensive neuroprotection, being effective against ethanol (200 and 400 mg/dl), gwHG, and aHP, alone and combined. BDNF afforded similar protection, but not against ethanol + gwHG. CNTF protected only against aHP. CNTF + BDNF, previously shown to act synergistically, protected against ethanol + aHP up to 800 mg/dl ethanol, but not, paradoxically, against ethanol alone, gwHG, or ethanol + gwHG, all conditions BDNF alone protected against. This study demonstrated that several neurotrophic factors are capable of mitigating neurotoxicity associated with ethanol, hypoglycemia and hypoxia.

Optimal 96-well plate set-up to avoid ethanol volatility when assessing ethanol cytotoxicity

An optimal design has been established that maintains a constant level of ethanol when utilizing specific wells within a 96-well culture plate. A control (non-ethanol-containing) column is also included within each plate for direct comparisons of the cytotoxic effects of a given concentration of ethanol.

Twenty-year outcome analysis of genetic screening programs for Tay-Sachs and beta-thalassemia disease carriers in high schools

Programs for education, screening, and counseling of senior-high-school students, in populations at high risk for Tay-Sachs and beta-thalassemia diseases, have existed for >20 years in Montreal. Four process and outcome variables are reported here: (i) voluntary participation rates in the high-school cohort; (ii) uptake rates for the screening test; (iii) origin of carrier couples seeking the prenatal diagnosis option in the programs; and (iv) change in incidence of the two diseases. Between 1972 and 1992, we screened 14,844 Ashkenazi-Jewish students, identified 521 HexA-deficient carriers (frequency 1:28), reached 89% of the demographic cohort in the educational component of the program, and achieved 67% voluntary participation in the subsequent screening phase. The corresponding data for the beta-thalassemia program are 25,274 students (mainly of Mediterranean origin) representing 67% of the cohort with 61% voluntary participation in the screening phase (693 carriers; frequency 1:36). From demographic data, we deduce that virtually all the carriers identified in the high-school screening program remembered their status, had their partner tested if they did not already know they were a carrier couple, and took up the options for reproductive counseling/prenatal diagnosis. In Montreal, the current origin of all couples using prenatal diagnosis for Tay-Sachs and beta-thalassemia diseases is the corresponding genetic screening/testing program, whereas, at the beginning of the programs, it was always because there was a history of an affected person in the family. Incidence of the two diseases has fallen by 90%-95% over 20 years; the rare new cases are born (with two exceptions) outside the target communities or to nonscreened couples.

U-type exchange in a paracentric inversion as a possible mechanism of origin of an inverted tandem duplication of chromosome 8

A mentally retarded male with dysmorphic features was found to have a de novo 46,XY,inv dup(8) (p.23.1-->12). Confirmation of the segments duplicated in the rearrangement was achieved by biochemical analysis of glutathione reductase, which maps to 8p21.1, and DNA studies using the chromosome specific probe y-19-1D (D85131), which maps to 8p21. Assay of cathepsin B, which has been localised to 8p22, did not differ from controls with normal chromosomal constitution. DNA studies using the Defensin 1 gene probe, which maps to 8p23, showed a previously undetected deletion of that segment. We propose that the inverted tandem duplication/deletion arose as a single U-type exchange within an inversion loop.

Cyclic mechanical deformation stimulates human lung fibroblast proliferation and autocrine growth factor activity

Cellular hypertrophy and hyperplasia and increased extracellular matrix deposition are features of tissue hypertrophy resulting from increased work load. It is known, for example, that mechanical forces play a critical role in lung development, cardiovascular remodeling following pressure overload, and skeletal muscle growth. The mechanisms involved in these processes, however, remain unclear. Here we examined the effect of mechanical deformation on fibroblast function in vitro. IMR-90 human fetal lung fibroblasts grown on collagen-coated silastic membranes were subjected to cyclical mechanical deformation (10% increase in culture surface area; 1 Hz) for up to 5 days. Cell number was increased by 39% after 2 days of deformation (1.43 +/- .01 x 10(5) cells/membrane compared with control, 1.03 +/- 0.02 x 10(5) cells; mean +/- SEM; P < 0.02) increasing to 163% above control by 4 days (2.16 +/- 0.16 x 10(5) cells compared with 0.82 +/- 0.03 x 10(5) cells; P < 0.001). The medium from mechanically deformed cells was mitogenic for IMR-90 cells, with maximal activity in the medium from cells mechanically deformed for 2 days (stimulating cell replication by 35% compared with media control; P < 0.002). These data suggest that mechanical deformation stimulates human lung fibroblast replication and that this effect is mediated by the release of autocrine growth factors.

In vitro expression of the alpha-smooth muscle actin isoform by rat lung mesenchymal cells: regulation by culture condition and transforming growth factor-beta

alpha-Smooth muscle actin (alpha SM actin)-containing cells recently have been demonstrated in intraalveolar lesions in both rat and human tissues following lung injury. In order to develop model systems for the study of such cells, we examined cultured lung cell lines for this phenotype. The adult rat lung fibroblast-like "RL" cell lines were found to express alpha SM actin mRNA and protein and to organize this actin into stress fiber-like structures. Immunocytochemical staining of subclones of the RL87 line demonstrated the presence in the cultures of at least four cell phenotypes, one that fails to express alpha SM actin and three distinct morphologic types that do express alpha SM actin. The proportion of cellular actin that is the alpha-isoform was modulated by the culture conditions. RL cells growing at low density expressed minimal alpha SM actin. On reaching confluent densities, however, alpha SM actin increased to at least 20% of the total actin content. This effect, combined with the observation that the most immunoreactive cells were those that displayed overlapping cell processes in culture, suggests that cell-cell contact may be involved in actin isoform regulation in these cells. Similar to the response of some smooth muscle cell lines, alpha SM actin expression in RL cells also was promoted by conditions, e.g., maintenance in low serum medium, which minimize cell division. alpha SM actin expression was modulated in RL cells by the growth factor transforming growth factor-beta. Addition of this cytokine to growing cells substantially elevated the proportion of alpha SM actin protein.(ABSTRACT TRUNCATED AT 250 WORDS)

Familial cold urticaria

Familial cold urticaria (FCU) is a rare autosomal dominant condition, first described in 1940. The onset is in early life in all reported cases. Symptoms are triggered by generalized exposure to cold air, particularly in damp and windy weather. The cutaneous lesions consist of erythematous macules or plaques, urticarial lesions and sometimes petechiae. Associated fever, chills, joint pains, nausea, stiffness and swelling of the hands and feet frequently occur. The symptoms are variable, ranging from mild to incapacitating. The pathogenesis of FCU remains unknown. To our knowledge only 10 pedigrees have been published, seven from the USA and one each from Holland, France and South Africa. We wish to report another extensive pedigree after having had the opportunity to investigate one member of the family in detail. A short form of this pedigree has been published elsewhere.

From ethical dilemma to hospital policy. The withholding or withdrawing of artificially provided nutrition and hydration

In 1990 St. Joseph's Hospital and Medical Center, Paterson, NJ, established a committee to create an institutional policy to facilitate the decision-making process when patients or their legally authorized surrogates request the withholding or withdrawing of artificially provided nutrition and hydration. Before drafting a policy, the committee agreed on the philosophical, ethical, and medical assumptions that would be the foundation for the policy. The group adopted nine policy assumptions and provided guidelines that address concerns common to all healthcare facilities. No policy that addresses the issue of when to withhold or withdraw life-sustaining treatment will be perfect, nor will it resolve all the complexities of such a decision. However, an imperfect policy is preferable to the absence of a policy, which can lead to an abuse of patients' rights and contribute to arbitrariness in medical decision making.

Quantitative autoradiographic analysis of excitatory amino acid receptors in the cat spinal cord

Using quantitative autoradiography, we have studied the density and distribution of N-methyl-D-aspartate (NMDA), kainate and AMPA receptors and the binding site for the sodium-dependent EAA transporter in sections from the cat spinal cord. NMDA, kainate and AMPA receptors were found in highest concentrations in laminae I and II of the dorsal horn. Lower levels of all receptors were seen in other regions of the spinal cord grey matter. The distribution of the sodium-dependent transporter was unlike that of any of the receptor populations with highest levels found in the ventral horn with slightly lower levels in other regions of grey matter. The pattern of binding sites was consistent throughout all levels of the spinal cord.

Smooth muscle cell markers in developing rat lung

We employed a panel of antibodies directed against cytoskeletal and contractile proteins in a developmental study to follow the differentiation and distribution of smooth muscle-like cells in the rat lung. We observed that, in the mesenchyme around developing airways and vessels, desmin replaces vimentin as the predominant intermediate filament as specialization toward smooth muscle occurs. Normally, desmin and smooth muscle myosin were expressed together in the cells and their acquisition appeared indicative of terminal differentiation of smooth muscle. In this regard, the maturation of vascular smooth muscle is delayed in the lung relative to that surrounding the developing air passages. alpha-smooth muscle actin-containing cells form a thicker coat around the primitive airway tubes and extend farther down the tree than desmin or smooth muscle myosin-positive cells. This suggests that the alpha-actin is a marker for initial differentiation of smooth muscle cells and that these cells arise from the enveloping mesenchyme. In the pseudoglandular and canalicular lung, alpha-actin-containing cells were also found in regions of epithelial tube cleft formation, suggesting an association with the process of branching morphogenesis. In addition, a large complement of alpha-actin-positive but smooth muscle myosin-negative cells were observed in the saccular interstitium during the period of secondary saccule formation and capillary reorganization that leads to final alveolarization. In summary, we note an association of smooth muscle-like, alpha-actin-containing cells with areas and periods of remodeling during normal pulmonary development. This observation may have relevance to the repair process in the adult lung.

Alpha smooth muscle actin expression in developing and adult human lung

Myofibroblast-like cells containing smooth muscle actin have been identified in lung injury and repair. These cells differ from typical smooth muscle cells by architectural configuration, location and lack of smooth muscle myosin. Their progenitors are unknown. We hypothesized that these cells might have a developmental analog critical to lung morphogenesis. Lung tissue from developing and adult human lungs was studied using a highly specific monoclonal antibody directed against alpha smooth muscle actin (ASMA). Cells immunoreactive for ASMA (ASMA cells) were identified prenatally in the form of smooth muscle investing the developing vasculature and airway structures. ASMA was not expressed in undifferentiated mesenchymal cells at any prenatal stage. Late in development, ASMA cells within the lung acinus increased proportionally to terminal airway and vascular complexity. In the early postnatal period, the specific distribution of ASMA cells within inflated lung became clearer, and three populations were identified: (1) typical smooth muscle investing the large airways and blood vessels; (2) small clusters of cells within the acinus distributed at the tips of septa protruding into the alveolar duct; (3) individual cells within the alveolar sac sparsely distributed near the junctions of individual alveoli, frequently in association with small blood vessels. We conclude that ASMA cells appear only in developing small and large airways and pulmonary vessels and that they may play a critical role in branching morphogenesis during development.

Alveolar epithelial cell keratin expression during lung development

Defining the expression and organization of keratins has provided insight into epithelial cell differentiation during tissue development and remodeling. We have used monoclonal antibodies to examine keratin distribution in lung epithelial cells in the rat from the preglandular phase of gestation to the adult. Of particular interest were the distributions of keratin No. 18 and keratin No. 19, since previous results have suggested these keratins may be important in alveolar epithelial cell transitions occurring in adult remodeling lung and in cultured type II cells. The epithelial tubes at 15 days of gestation do not react with 24A3 monoclonal antibody to keratin No. 18, nor is this antigen apparent by gel or immunoblot analysis. Staining is apparent at day 16, however, showing a light punctate pattern at the basal edge of the cells, and becomes prominent by day 17, with intensity greatest in the larger airway tubes. The intensity and number of cells in the parenchyma staining with 24A3 peaks at postnatal days 5 to 10, when proliferation and cytodifferentiation of type I and type II cells is most active. In the adult, staining of type II cells is present mainly at the cell periphery, and occasional reactive attenuated type I-like cells can be observed. Keratin No. 19 immunoreactivity is not present in the primitive epithelial tube until 19 days' gestation but predominantly stains type II pneumocytes in the adult rat lung throughout the entire cell. AE3 antibody to basic keratins stains similarly to keratin No. 19. We conclude that keratin No. 18 is expressed at high levels in type II cells during development in periods of intense proliferation and alveolarization. This correlates with our previous observations on keratin expression following bleomycin lung injury.

Cytomatrix synthesis in MDCK epithelial cells

Detailed information regarding the synthesis rates of individual protein components is important in understanding the assembly and dynamics of the cytoskeletal matrix of eukaryotic cells. As an approach to this topic, the dual isotope technique of Clark and Zak (J. Biol. Chem., 256:4863-4870, 1981), was employed to measure fractional synthesis rates (FSRs) in growing and quiescent cultures of MDCK epithelial cells. Cell protein was labeled to equilibrium with [14C]leucine over several days and then pulse-labeled for 4 hours with [3H]leucine. FSRs (as percent per hour) were calculated from the 3H/14C ratio of cell extracts or individual proteins separated by two-dimensional polyacrylamide gel electrophoresis and the 3H/14C ratio of free leucine in the medium. Synthesis of total cell protein rose from approximately 1.4%/hour in quiescent cells to 3.5%/hour in the growing cultures. The latter rate was sufficient to account for the rate of protein accumulation and a low level of turnover in the growing cultures. The FSR of the buffered-Triton soluble extract was higher and the cytoskeletal FSR significantly lower than that for total protein in quiescent monolayers. This difference, however, was not observed in growing cultures. A distinct pattern of differences was seen in the FSRs of individual cytoskeletal proteins in the quiescent cultures. Vimentin synthesis was significantly lower than that of the keratins and the keratin FSRs were not obviously matched in pairwise fashion. Unexpectedly, the FSRs of alpha- and beta-tubulin diverged in quiescent cells with alpha-tubulin turnover exceeding beta-tubulin. Likewise, components of the microfilament lattice showed unequal fractional synthesis rates, myosin and alpha-actinin being faster than actin. In addition, the FSR for globular actin exceeded that of the cytoskeletal associated form. The results suggest that metabolic coupling between individual cellular filament systems is not strict. The data are, however, consistent with models that predict that assembly of a subcellular structure influences the turnover of its component proteins.

The enhanced association of keratin with hepatoma cell nuclei

A monoclonal antibody to rat hepatoma keratin demonstrates a close association of intermediate filaments with the nucleus in hepatoma cells. Immunoblot analysis of nuclear fractions and immunofluorescence of nuclei both prepared by standard procedures, indicate that intermediate filament proteins are consistently present. Sodium citrate extraction of these preparations diminishes the amount of intermediate filament proteins but does not totally remove the antigenic moieties, suggesting a tight association of intermediate filaments with nuclei. The results from both immunoblot analysis and immunofluorescent localization demonstrate the increased amount of keratins associated with hepatoma cell nuclei.

Alpha-smooth muscle actin is transiently expressed in embryonic rat cardiac and skeletal muscles

Actin isoform expression may change during development, and in certain physiological, experimental and pathological situations. It is accepted that during sarcomeric (skeletal and cardiac) muscle development, the alpha-skeletal and alpha-cardiac isoforms of actin accumulate rapidly at the onset of muscle fibre formation, while there is a rapid fall in the expression of nonmuscle (beta and gamma) actin isoforms. Here we show that, before birth, both skeletal and myocardial cells express significant amounts of alpha-smooth muscle actin mRNA and protein. This expression is transient and disappears over the 1-7 days following birth. Our findings show that the program regulating actin isoform expression in sarcomeric muscle development is complex and that alpha-smooth muscle actin participates in this process.

Keratin species in type II pneumocytes in culture and during lung injury

A detailed understanding of alveolar epithelial cell transitions during remodeling after lung injury requires the identification of specific markers. We have developed a panel of monoclonal antibodies against species of the intermediate filament protein, keratin. These individual species are recognized markers of the state of differentiation of various epithelial cells. These and complementary protein analytic methods have been applied to studies of isolated, enriched Type II pneumocyte preparations as well as to normal and injured lung tissues. Monoclonal antibody 24A3, initially raised against Morris hepatoma 7777 keratins, decorated a filament network in isolated cultured rat Type II pneumocytes by indirect immunofluorescence; it reacts by 2-dimensional polyacrylamide gel immunoblot procedures with an acidic, 46,000-dalton keratin. Monoclonal antikeratin antibodies AE1 and AE3, raised against human epidermal keratins, reacted poorly with isolated Type II cells; however, AE3 reacted by immunoblot technique with the 55,000-dalton keratin subclass. The bronchial epithelium reacted intensely with 24A3 as well as with a mix of AE1 plus AE3 in ethanol-fixed, paraffin-embedded sections of normal and injured rat lung. Alveolar regions of normal lung reacted poorly with all 3 antibodies, however, as visualized by light microscopy. At the same time, very large, presumptive epithelial cells in the alveolar regions stained intensely with 24A3 3 days after intratracheal instillation of bleomycin, whereas thin cells lining the alveoli in injured regions were intensely reactive 14 days after bleomycin treatment. These elongated cells may represent Type II pneumocytes in the process of converting to Type I cells.

Synthesis of cytoskeletal and contractile proteins by cultured IMR-90 fibroblasts

Models of the assembly of cytoskeletal and contractile proteins of eukaryotic cells require quantitative information about the rates of synthesis of individual component proteins. We applied the dual isotope technique of Clark and Zak (1981, J. Biol. Chem., 256:4863-4870) to measure the synthesis rates of cytoskeletal and contractile proteins in stationary and growing cultures of IMR-90 fibroblasts. Fibroblast proteins were labeled to equilibrium with [14C]leucine over several days, at the end of which there was a 4-h pulse with [3H]leucine. Fractional synthesis rates (percent per hour) were calculated from the 3H/14C ratio of cell protein extracts or protein purified by one- or two-dimensional polyacrylamide gel electrophoresis and the 3H/14C ratio of medium-free leucine. The average fractional synthesis rate for total, SDS- or urea-soluble; Triton-soluble; and cytoskeletal protein extracts in stationary cells each was approximately 4.0%/h. The range of values for the synthesis of individual proteins from total cell extracts or cytoskeletal extracts sliced from one-dimensional gels was similar, though this range was greater than that for major proteins of Triton-soluble protein extracts. Three specific cytoskeletal proteins--actin, vimentin, and tubulin--were synthesized at similar rates that were significantly slower than the average fractional synthesis rate for total protein. Myosin, on the other hand, was synthesized faster than average. Synthesis rates were the same for beta-and gamma-actin and polymerized (cytoskeletal extract) vs. Triton-soluble actin. The same was true for alpha- and beta-tubulin and two different forms of vimentin. Synthesis rates were uniformly higher in growing cells, though the same pattern of differential rates was observed as for stationary cells. Synthesis rates in growing cells were higher than the rate necessary to maintain the growth rate, even for those cytoskeletal proteins being synthesized slowly. Therefore, there appears to be some turnover of these cytoskeletal elements even during growth. We conclude that proteins in cytoskeletal extracts may have nonuniform rates of synthesis, but at least one important subclass of cytoskeletal proteins that comprise filament subunits have the same synthesis rates.

Bleomycin treatment of chick fibroblasts causes an increase of polysomal type I procollagen mRNAs. Reversal of the bleomycin effect by dexamethasone

Bleomycin treatment of primary chick skin fibroblasts and chick lung fibroblasts resulted in a selective dose-dependent increase of cell layer procollagen synthesis. Solid support hybridization of total cellular RNA to 32P-labeled pro-alpha 1(I) and pro-alpha 2(I) cDNAs did not indicate an increase of total cellular procollagen type I mRNAs in bleomycin-treated cells. However, bleomycin treatment of chick skin fibroblasts causes a redistribution of procollagen type I mRNAs within the nuclear, cytoplasmic, and polysomal subcellular fractions. Both the nuclear and cytoplasmic procollagen type I mRNAs are significantly decreased in concentration after bleomycin administration. In contrast, the polysomal procollagen type I mRNAs are significantly increased in both chick skin and lung fibroblasts treated with bleomycin. Administration of dexamethasone to bleomycin-treated fibroblasts resulted in a reversal of the bleomycin-induced increase in cell layer procollagen synthesis. The increased amounts of polysomal procollagen type I mRNAs in bleomycin-treated cells were also reduced by subsequent administration of dexamethasone. These data indicate that bleomycin treatment of chick skin and chick lung fibroblasts results in a specific increase in procollagen synthesis in the cell layer which is mediated by elevated levels of polysomal type I procollagen mRNAs via a repartitioning of these mRNAs within the fibroblast. Furthermore, dexamethasone reverses the bleomycin-induced elevations of both cell layer procollagen synthesis and polysomal type I procollagen mRNAs.

Dexamethasone decreases the amounts of type I procollagen mRNAs in vivo and in fibroblast cell cultures

Dexamethasone treatment of neonatal chicks resulted in a time- and dose-dependent selective decrease of skin collagen synthesis. Total RNA of chick skin was isolated and hybridized to the cloned cDNAs pCg54 for pro-alpha 1 (I) mRNA and pCg45 for pro-alpha 2(I) mRNA. RNA isolated from the total skin of chicks receiving various doses of dexamethasone had dose-related decreases of pro-alpha 1 (I) and pro-alpha 2(I) mRNAs. The decrease of type I procollagen mRNAs for various doses of dexamethasone were similar to the decreases observed for collagen synthesis in vivo. Dexamethasone treatment of chick skin and chick lung fibroblasts resulted in a selective decrease of procollagen synthesis. A dose-related decrease of procollagen synthesis was observed with chick skin fibroblasts. Dexamethasone-treated chick skin and chick lung fibroblasts had decreased levels of pro-alpha 1 (I) and pro-alpha 2(I) mRNAs as determined by solid support hybridization with pCg54 and pCg45. The dexamethasone-mediated decreases of type I procollagen mRNAs in skin fibroblasts and lung fibroblasts were similar to the decreases observed in procollagen synthesis.

The effect of alcohols on guanosine 5'-diphosphate-3'-diphosphate metabolism in stringent and relaxed Escherichia coli

The effects of a series of alcohols on the stringent response system of Escherichia coli were studied. The alcohols used could be divided into two groups on the basis of the response of pppGpp and ppGpp to the growth downshift induced by the alcohols. The cells responded to the alcohols, methanol, ethanol, and propanol, as if they were being starved of amino acids. In the stringent strain CP78 these alcohols induced pppGpp and ppGpp accumulation and curtailed RNA synthesis, whereas in the relaxed strain CP79, both of these responses were absent. It was determined that this response was most likely due to an interference by these alcohols with the uptake of amino acids required by these strains. By contrast both stringent and relaxed cells elevated their level of ppGpp and decreased RNA accumulation when treated with butanol or pentanol. This response is similar to the effect of carbon source limitation. It was determined that the elevation of ppGpp in the stringent strain was primarily the result of increased ppGpp synthesis in response to these alcohols. In the relaxed strain the rise in ppGpp was dependent on a decrease in ppGpp degradation coupled with a moderate increase in ppGpp synthesis. This stimulation of ppGpp synthesis in relaxed cells, although small, suggests the existence of an enzyme distinct from stringent factor which is capable of synthesizing ppGpp. Data are presented which suggest that the activity of this enzyme is coupled to the potential for protein synthesis and energy availability of the cell, perhaps being regulated by the overall ratio of unchanged to amino-acylated tRNA.