Heterozygous frameshift variants in HNRNPA2B1 cause early-onset oculopharyngeal muscular dystrophy

Missense variants in RNA-binding proteins (RBPs) underlie a spectrum of disease phenotypes, including amyotrophic lateral sclerosis, frontotemporal dementia, and inclusion body myopathy. Here, we present ten independent families with a severe, progressive muscular dystrophy, reminiscent of oculopharyngeal muscular dystrophy (OPMD) but of much earlier onset, caused by heterozygous frameshift variants in the RBP hnRNPA2/B1. All disease-causing frameshift mutations abolish the native stop codon and extend the reading frame, creating novel transcripts that escape nonsense-mediated decay and are translated to produce hnRNPA2/B1 protein with the same neomorphic C-terminal sequence. In contrast to previously reported disease-causing missense variants in HNRNPA2B1, these frameshift variants do not increase the propensity of hnRNPA2 protein to fibrillize. Rather, the frameshift variants have reduced affinity for the nuclear import receptor karyopherin β2, resulting in cytoplasmic accumulation of hnRNPA2 protein in cells and in animal models that recapitulate the human pathology. Thus, we expand the phenotypes associated with HNRNPA2B1 to include an early-onset form of OPMD caused by frameshift variants that alter its nucleocytoplasmic transport dynamics.

Missense variants in RNA-binding proteins underlie many diseases. Here the authors report an oculopharyngeal muscular dystrophy caused by heterozygous frameshift mutations in HNRNPA2B1 that alter its nucleocytoplasmic transport dynamics and result in cytoplasmic accumulation of hnRNPA2 protein.

Association of Level I and II Trauma Center Expansion With Insurer Payments in Texas From 2011 to 2019

This cross-sectional study examines whether the expansion of level I and II trauma centers in Texas was associated with higher prices or more trauma activation fees.

Candidate Electromagnetic Counterpart to the Binary Black Hole Merger Gravitational-Wave Event S190521g

We report the first plausible optical electromagnetic counterpart to a (candidate) binary black hole merger. Detected by the Zwicky Transient Facility, the electromagnetic flare is consistent with expectations for a kicked binary black hole merger in the accretion disk of an active galactic nucleus [B. McKernan, K. E. S. Ford, I. Bartos et al., Astrophys. J. Lett. 884, L50 (2019)AJLEEY2041-821310.3847/2041-8213/ab4886] and is unlikely [<O(0.01%))] due to intrinsic variability of this source. The lack of color evolution implies that it is not a supernova and instead is strongly suggestive of a constant temperature shock. Other false-positive events, such as microlensing or a tidal disruption event, are ruled out or constrained to be <O(0.1%). If the flare is associated with S190521g, we find plausible values of total mass M_{BBH}∼100  M_{⊙}, kick velocity v_{k}∼200  km s^{-1} at θ∼60° in a disk with aspect ratio H/a∼0.01 (i.e., disk height H at radius a) and gas density ρ∼10^{-10}  g cm^{-3}. The merger could have occurred at a disk migration trap (a∼700r_{g}; r_{g}≡GM_{SMBH}/c^{2}, where M_{SMBH} is the mass of the active galactic nucleus supermassive black hole). The combination of parameters implies a significant spin for at least one of the black holes in S190521g. The timing of our spectroscopy prevents useful constraints on broad-line asymmetry due to an off-center flare. We predict a repeat flare in this source due to a reencountering with the disk in ∼1.6  yr(M_{SMBH}/10^{8}  M_{⊙})(a/10^{3}r_{g})^{3/2}.

hnRNPDL Phase Separation Is Regulated by Alternative Splicing and Disease-Causing Mutations Accelerate Its Aggregation

Prion-like proteins form multivalent assemblies and phase separate into membraneless organelles. Heterogeneous ribonucleoprotein D-like (hnRNPDL) is a RNA-processing prion-like protein with three alternative splicing (AS) isoforms, which lack none, one, or both of its two disordered domains. It has been suggested that AS might regulate the assembly properties of RNA-processing proteins by controlling the incorporation of multivalent disordered regions in the isoforms. This, in turn, would modulate their activity in the downstream splicing program. Here, we demonstrate that AS controls the phase separation of hnRNPDL, as well as the size and dynamics of its nuclear complexes, its nucleus-cytoplasm shuttling, and amyloidogenicity. Mutation of the highly conserved D378 in the disordered C-terminal prion-like domain of hnRNPDL causes limb-girdle muscular dystrophy 1G. We show that D378H/N disease mutations impact hnRNPDL assembly properties, accelerating aggregation and dramatically reducing the protein solubility in the muscle of Drosophila, suggesting a genetic loss-of-function mechanism for this muscular disorder.

Exploring reasons for overuse of contralateral prophylactic mastectomy in Canada

Background

Contralateral prophylactic mastectomy (cpm) in women with known unilateral breast cancer (bca) has been increasing despite the lack of supportive evidence. The purpose of the present study was to identify the determinants of cpm in women with unilateral bca.

Methods

This qualitative descriptive study used semi-structured interviews informed by the Theoretical Domains Framework. We interviewed 74 key informants (surgical oncologists, plastic surgeons, medical oncologists, radiation oncologists, nurses, women with bca) across Canada. Interviews were analyzed using thematic analysis and an analysis for shared and discipline-specific beliefs.

Results

In total, 58 factors influencing the use of cpm were identified: 26 factors shared by various health care professional groups, 15 discipline-specific factors (identified by a single health care professional group), and 17 factors shared by women with unilateral bca. Health care professionals identified more factors discouraging the use of cpm (n = 26) than encouraging its use (n = 15); women with bca identified more factors encouraging use of cpm (n = 12) than discouraging its use (n = 5). The factor most commonly identified by health care professionals that encouraged cpm was lack of awareness of existing evidence or guidelines for the appropriate use of cpm (n = 44, 75%). For women with bca, the factor most likely influencing their decision for cpm was wanting a better esthetic outcome (n = 14, 93%).

Conclusions

Multiple factors discouraging and encouraging the use of cpm in unilateral bca were identified. Those factors identify potential individual, team, organization, and system targets for behaviour change interventions to reduce cpm.

Patient decision aid for contralateral prophylactic mastectomy for use in the consultation: a feasibility study

Background

Rates of contralateral prophylactic mastectomy (cpm) continue to rise internationally despite evidence-based guidance strongly discouraging its use in most women with unilateral breast cancer. The purpose of the present study was to develop and assess the feasibility of a knowledge translation tool [a patient decision aid (da)] designed to enhance evidence-informed shared decision-making about cpm.

Methods

A consultation da was developed using the Ottawa Patient Decision Aid Development eTraining in consultation with clinicians and knowledge translation experts. The final da was then assessed for feasibility with health care professionals and patients across Canada. The assessment involved a survey completed online (health care professionals) or by telephone (patients). Survey data were analyzed using descriptive statistics for closed-ended questions and qualitative content analysis for open-ended questions.

Results

The 51 participants who completed the survey included 39 health care professionals and 12 patients. The da was acceptable; 88% of participants viewed it as having the right amount of information or slightly more or less information than they would like. Almost all participants (98%) felt that the da would prepare patients to make better decisions. The aid was perceived to be usable, with 73% of participants stating that they would be willing to use or share the da.

Conclusions

The cpm patient da developed for the present study was viewed by health care professionals and patients across Canada to be acceptable and usable during the clinical consultation. It holds promise as a knowledge translation tool to be used by clinicians in consultation with women who have unilateral breast cancer to enhance evidence-informed and shared decision-making with respect to undergoing cpm.

Nuclear-Import Receptors Reverse Aberrant Phase Transitions of RNA-Binding Proteins with Prion-like Domains

RNA-binding proteins (RBPs) with prion-like domains (PrLDs) phase transition to functional liquids, which can mature into aberrant hydrogels composed of pathological fibrils that underpin fatal neurodegenerative disorders. Several nuclear RBPs with PrLDs, including TDP-43, FUS, hnRNPA1, and hnRNPA2, mislocalize to cytoplasmic inclusions in neurodegenerative disorders, and mutations in their PrLDs can accelerate fibrillization and cause disease. Here, we establish that nuclear-import receptors (NIRs) specifically chaperone and potently disaggregate wild-type and disease-linked RBPs bearing a NLS. Karyopherin-β2 (also called Transportin-1) engages PY-NLSs to inhibit and reverse FUS, TAF15, EWSR1, hnRNPA1, and hnRNPA2 fibrillization, whereas Importin-α plus Karyopherin-β1 prevent and reverse TDP-43 fibrillization. Remarkably, Karyopherin-β2 dissolves phase-separated liquids and aberrant fibrillar hydrogels formed by FUS and hnRNPA1. In vivo, Karyopherin-β2 prevents RBPs with PY-NLSs accumulating in stress granules, restores nuclear RBP localization and function, and rescues degeneration caused by disease-linked FUS and hnRNPA2. Thus, NIRs therapeutically restore RBP homeostasis and mitigate neurodegeneration.

C9orf72 Dipeptide Repeats Impair the Assembly, Dynamics, and Function of Membrane-Less Organelles

Expansion of a hexanucleotide repeat GGGGCC (G₄C₂) in C9ORF72 is the most common cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Transcripts carrying (G₄C₂) expansions undergo unconventional, non-ATG-dependent translation, generating toxic dipeptide repeat (DPR) proteins thought to contribute to disease. Here, we identify the interactome of all DPRs and find that arginine-containing DPRs, polyGly-Arg (GR) and polyPro-Arg (PR), interact with RNA-binding proteins and proteins with low complexity sequence domains (LCDs) that often mediate the assembly of membrane-less organelles. Indeed, most GR/PR interactors are components of membrane-less organelles such as nucleoli, the nuclear pore complex and stress granules. Genetic analysis in Drosophila demonstrated the functional relevance of these interactions to DPR toxicity. Furthermore, we show that GR and PR altered phase separation of LCD-containing proteins, insinuating into their liquid assemblies and changing their material properties, resulting in perturbed dynamics and/or functions of multiple membrane-less organelles.

Prenatal and postnatal markers of severity in congenital diaphragmatic hernia have similar prognostic ability

OBJECTIVES

The purpose of this study was to compare prenatal versus postnatal markers of congenital diaphragmatic hernia (CDH) severity at a single fetal-care center.

METHODS

A retrospective study was performed of patients having a complete prenatal evaluation and surgical repair (n = 55). Observed-to-expected lung-to-head ratio (o/eLHR), observed-to-expected total lung volume (o/eTLV), liver position (LP), a predictive dependent variable from logistic regression of o/eLHR and liver position (o/eLHR + LP), and diaphragmatic defect size per the CDH Study Group A-D classification were plotted into receiver-operating characteristics (ROC) curves. Survival and need for extracorporeal membrane oxygenation (ECMO) were primary outcomes.

RESULTS

Survival was 69%, and ECMO utilization was 56%. Distribution was 80% left-sided defects. In the survival ROC curve, the area under the curve (AUC) for o/eLHR was 0.73, o/eTLV 0.74, LP 0.73, o/eLHR + LP 0.78, and defect size 0.84 (p = 0.23). The ROC curve for ECMO support showed o/eLHR had an AUC of 0.82, o/eTLV 0.89, LP 0.79, o/eLHR + LP 0.87, and defect size 0.90 (p = 0.19). The AUCs were similar when only left-sided CDH was analyzed.

CONCLUSIONS

These data suggest that prenatal evaluation was equivalent to the postnatal diaphragmatic defect classification for predicting survival and need for ECMO in CDH patients.

Phase separation by low complexity domains promotes stress granule assembly and drives pathological fibrillization

Stress granules are membrane-less organelles composed of RNA-binding proteins (RBPs) and RNA. Functional impairment of stress granules has been implicated in amyotrophic lateral sclerosis, frontotemporal dementia, and multisystem proteinopathy-diseases that are characterized by fibrillar inclusions of RBPs. Genetic evidence suggests a link between persistent stress granules and the accumulation of pathological inclusions. Here, we demonstrate that the disease-related RBP hnRNPA1 undergoes liquid-liquid phase separation (LLPS) into protein-rich droplets mediated by a low complexity sequence domain (LCD). While the LCD of hnRNPA1 is sufficient to mediate LLPS, the RNA recognition motifs contribute to LLPS in the presence of RNA, giving rise to several mechanisms for regulating assembly. Importantly, while not required for LLPS, fibrillization is enhanced in protein-rich droplets. We suggest that LCD-mediated LLPS contributes to the assembly of stress granules and their liquid properties and provides a mechanistic link between persistent stress granules and fibrillar protein pathology in disease.

Antizyme, a mediator of ubiquitin-independent proteasomal degradation and its inhibitor localize to centrosomes and modulate centriole amplification

The potential tumor suppressor antizyme and its endogenous inhibitor (antizyme inhibitor, AZI) have been implicated in the ubiquitin-independent proteasomal degradation of proteins involved in cell proliferation as well as in the regulation of polyamine levels. We show here that both antizyme and AZI concentrate at centrosomes and that antizyme preferentially associates with the maternal centriole. Interestingly, alterations in the levels of these proteins have opposing effects on centrosomes. Depletion of antizyme in various cell lines and primary cells leads to centrosome overduplication, whereas overexpression of antizyme reduces numerical centrosome abnormalities. Conversely, silencing of the antizyme inhibitor, AZI, results in a decrease of numerical centrosome abnormalities, whereas overexpression of AZI leads to centrosome overduplication. We further show that the numerical centrosome abnormalities are due to daughter centriole amplification. In summary, our results demonstrate that alterations in the antizyme/AZI balance cause numerical centrosomal defects and suggest a role for ubiquitin-independent proteasomal degradation in centrosome duplication.

The relation between identification and discrimination of vowels in young and elderly listeners

This study examined both the identification and discrimination of vowels by three listener groups: elderly hearing-impaired, elderly normal-hearing, and young normal-hearing. Each hearing-impaired listener had a longstanding symmetrical, sloping, mild-to-moderate sensorineural hearing loss. Two signal levels [70 and 95 dB sound-pressure level (SPL)] were selected to assess the effects of audibility on both tasks. The stimuli were four vowels, /I,e, epsilon, ae/, synthesized for a female talker. Difference limens (DLs) were estimated for both F1 and F2 formants using adaptive tracking. Discrimination DLs for F1 formants were the same across groups and levels. Discrimination DLs for F2 showed that the best formant resolution was for the young normal-hearing group, the poorest was for the elderly normal-hearing group, and resolution for the elderly hearing-impaired group fell in between the other two at both signal levels. Only the elderly hearing-impaired group had DLs that were significantly poorer than those of the young listeners at the lower, 70 dB, level. In the identification task at both levels, young normal-hearing listeners demonstrated near-perfect performance (M = 95%), while both elderly groups were similar to one another and demonstrated lower performance (M = 71%). The results were examined using correlational analysis of the performance of the hearing-impaired subjects relative to that of the normal-hearing groups. The results suggest that both age and hearing impairment contribute to decreased vowel perception performance in elderly hearing-impaired persons.

Differences in performance between Oticon MultiFocus Compact and ReSound BT2-E hearing aids

Differences in performance were evaluated between binaural fittings of the Oticon MultiFocus (MF) and ReSound BT2-E on 25 hearing-impaired subjects across two sites. Subjects were initially fit using each manufacturer's algorithm and adjustments were made at 1 week based on subjects' responses to diary questions. Performance was assessed after a 4- to 6-week trial period with each hearing aid set using the Speech Perception in Noise (SPIN) test administered at 50, 65, and 80 dB SPL, the Abbreviated Profile of Hearing Aid Benefit (APHAB) questionnaire, loudness judgments of female connected discourse at 65 and 80 dB SPL, and an overall preference selection. The MF yielded significantly better SPIN scores at 50 and 65 dB SPL, while the BT2-E yielded a significantly better score at 80 dB SPL. No statistically significant differences were found in the APHAB benefit scores between the hearing aid sets, but both sets were significantly better than the subjects' own hearing aids on three of the four subscales. The MF produced slightly higher mean loudness judgments at both input levels than the BT2-E. Finally, 12 subjects preferred the BT2-E, 10 subjects preferred the MF, and three subjects stated no preference. The results are discussed in terms of audiogram effects on preference and effects of differences in signal processing approaches between the devices.

Evaluation of the use of a new compact disc for auditory perceptual assessment in the elderly

The present study examined the performance of 40 normal-hearing young adults and 38 elderly adults, some normal hearing and some hearing impaired, on the Department of Veterans Affairs' new compact disc (VA-CD) for auditory perceptual assessment. Principal-components factor analyses were performed on the test scores from each group of subjects with very similar results obtained from each group in terms of the number of factors identified (3), the percentage of variance explained by these factors individually and collectively (about 72%), and the association of various test scores with each factor. The 10 tests examined here were found to be associated with three underlying factors identified as a general speech-understanding ability (about 42% of variance), temporal sequencing capacity (about 18% of variance), and processing ability under conditions of dichotic competition (about 12% of variance). Among the elderly, hearing loss was strongly and negatively associated with general speech-recognition ability, whereas age was moderately associated with the other two factors. Test scores for several measures of auditory perceptual processing were negatively affected by the presence of peripheral hearing loss in the elderly even when administered at the highest recommended presentation level (90 dB SPL). In addition, some tests among those examined were found to have inadequate test-retest reliability for clinical use with the elderly.

Reliability and stability of various hearing-aid outcome measures in a group of elderly hearing-aid wearers

Twenty elderly persons with hearing impairment were fit with binaural in-the-ear hearing aids and followed for a 6-month period post-fit. Several hearing-aid outcome measures were obtained at 0, 7, 15, 30, 60, 90, and 180 days post-fit. Outcome measures included (a) objective measures of benefit obtained with nonsense-syllable materials in quiet (CUNY Nonsense Syllable Test, NST) and sentences in multitalker babble (Hearing in Noise Test, HINT); (b) two subjective measures of benefit, one derived from pre-fit/post-fit comparisons on a general scale of hearing handicap (Hearing Handicap Inventory for the Elderly, HHIE) and the other based on a subjective scale of post-fit hearing-aid benefit (Hearing Aid Performance Inventory, HAPI); (c) a questionnaire on hearing-aid satisfaction; (d) an objective measure of hearing-aid use; and (e) a subjective measure of hearing-aid use. Reliability and stability of each measure were examined through repeated-measures analyses of variance, a series of test-retest correlations, and, where possible, scatterplots of the scores against their corresponding 95% critical differences. Many of the measures were found to be both reliable and stable indicators of hearing-aid outcome.

The effect of neonatal treatment of rats with nerve growth factor on the blood pressure and structure of the mesenteric arteries

Newborn male Wistar rats were treated with nerve growth factor daily by subcutaneous injection for 2 weeks, and control rats were treated with either cytochrome c or buffered saline. Average body weight of the treated animals was lower than that of the controls during the 2 weeks of treatment, but became similar to that of the controls thereafter. Tissue levels of norepinephrine were elevated in the brain, adrenal glands, mesenteric arteries, and vas deferens of the treated animals immediately after the treatment, but became similar in the three groups 2 weeks after the termination of the treatment. Blood pressure and heart rate were measured beginning at 4 weeks of age until 28 weeks, when the rats were sacrificed and the mesenteric arteries sampled for morphometric measurements of vessel wall dimensions. Pretreatment with nerve growth factor did not affect blood pressure, nor heart rate. Structural alteration of the three types of mesenteric arteries was also absent in the treated animals. We conclude that even though neonatal treatment of normal Wistar rats with nerve growth factor for 2 weeks induced an elevation of the norepinephrine levels in several tissues at the end of the treatment period, it was not sufficient to produce hypertension and structural alterations in the blood vessels.

Sensory nerves in adult rats regenerate and restore sensory function to the skin independently of endogenous NGF

We have investigated the possible roles of NGF, and of impulse activity, in the regeneration of sensory nerves. Unexpectedly, the ability of crushed axons to regrow and to restore functional recovery of three sensory modalities in adult rat skin (A alpha-mediated touch, A delta-mediated mechanonociception, and C-fiber-mediated heat nociception) was totally unaffected by anti-NGF treatment. This finding applied even when the anti-NGF dosage was almost eight times that which entirely blocked collateral sprouting of the undamaged axons of both classes of nociceptive nerves (the A alpha-axons do not sprout in adult animals). In the same anti-NGF-treated animal, regeneration would proceed normally on the one side, while collateral sprouting was prevented on the other. Light microscopic and EM examination revealed that in the denervated skin the regenerating axons utilized the same dermal perineurial pathways followed by collaterally sprouting axons. Regeneration within these antibody-accessible pathways progressed normally during anti-NGF treatment, extending 1-2 cm beyond the former field borders, that is, into territory whose invasion by collaterally sprouting axons was totally blocked. The blood-nerve barrier is absent within the degenerating peripheral nerve trunk, a putative NGF source for regenerating fibers but not for sprouting ones. The NGF-independent regeneration was also found to be unaffected when putative spinal cord sources of NGF were eliminated by dorsal root excision. Anti-NGF treatment also failed to block regeneration across 4 mm excision gaps in the nerve trunk. The daily anti-NGF regime continued to be effective for at least 8 weeks, at which time newly evoked collateral sprouting could still be blocked. Exogenous NGF, in doses that evoke collateral sprouting de novo in normal skin, failed to influence regeneration. Finally, an electrical stimulus regime, which markedly reduces the latency of collateral sprouting, failed to affect the time to arrival of regenerating axons at the skin, or the rate of their arborization in it. We conclude that, in striking contrast to their collateral sprouting, the regeneration of nociceptive axons occurs independently of endogenous NGF and is unaffected by impulse activity. These findings further support the proposal that these two growth behaviors have basically different biological functions in the organism.

Endogenous NGF and nerve impulses regulate the collateral sprouting of sensory axons in the skin of the adult rat

We have investigated the co-involvement of endogenous NGF and impulses in the collateral sprouting of cutaneous sensory nerves in adult rats, specifically the A delta-axons involved in mechanonociception and the C-fibers that mediate heat nociception. Their collateral sprouting was measured by the progressive expansion, respectively, of the behaviorally defined "pinch" and "heat" fields into surrounding denervated skin (the light-touch A alpha-fibers do not sprout in adult mammals). The expansions of such "isolated" fields were totally prevented in animals injected daily with anti-NGF serum, but developed normally after treatment was discontinued. Light microscopic and EM examination of the skin confirmed that the effect of the anti-NGF treatment was attributable to its prevention of collateral sprouting. Initiation of treatment would also rapidly halt sprouting already in progress. Finally, intradermal injections of purified NGF protein would not only increase the rate of nociceptive fiber sprouting, but also evoke sprouting de novo within normally innervated skin (again, A alpha-axons were unaffected). We conclude that the collateral sprouting of intact nociceptive nerves following partial denervation of skin is entirely dependent on endogenous NGF. The observed latency of this sprouting was 10-12 d; we estimate, however, that at least 2 d of field expansion is required for its reliable detection. Thus, about 8-10 d are required for NGF levels in the skin to rise to effective levels, and for the neurons to respond and initiate sprouting. From indirect findings, the NGF component of this sprouting latency appears to be about 2 d. In accord with earlier findings, the remaining "initiation time" was reduced by 5-6 d if the neurons were briefly excited, even 2 d prior to the isolation of their fields. Unexpectedly, this phenomenon of "precocious sprouting" requires that endogenous NGF be available; the sprouting latency reverted to normal values when the conditioning impulses were evoked during a 2 d anti-NGF "umbrella." In contrast to the impulse-sensitive neuronal mechanisms involved in the initiation of sprouting, those underlying the sprouting rate were unaffected by nerve activity and were entirely dependent on the level of endogenous NGF. We suggest that interactions like that revealed in these studies between a sprouting agent and impulses that seem to prime the neuron's response to it contribute to plasticity within the nervous system.

Combined effect of neonatal sympathectomy and adrenal demedullation on blood pressure and vascular changes in spontaneously hypertensive rats

Neonatal sympathectomy using a combined treatment with antiserum to nerve growth factor and guanethidine during the first 4 weeks after birth was carried out in spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats. Bilateral adrenal demedullation was performed in 4-week-old sympathectomized SHR and WKY rats. The development of hypertension in SHR was prevented by sympathectomy, but the blood pressure (BP) was still higher than in age-matched WKY rats. Demedullation reduced the BP of sympathectomized SHR to the same level as that of WKY rats. Heart rates of SHR and WKY rats were not affected by the treatments. Morphometric measurements of the mesenteric arteries showed that sympathectomy significantly reduced the medial mass in the mesenteric arteries of SHR, mainly through a reduction in the number of smooth muscle cell layers. In sympathectomized SHR, demedullation increased the lumen size of muscular arteries under maximally relaxed conditions, which might explain the further reduction in BP in these animals. Demedullation in sympathectomized SHR and WKY rats caused a decrease in smooth muscle cell layers in the superior mesenteric artery, but the same treatment resulted in a slight increase in the number of smooth muscle cell layers in the large and small mesenteric arteries of SHR and WKY rats. Adventitial area was increased in some mesenteric arteries of SHR and WKY rats by sympathectomy, and demedullation caused a further increase in the size of adventitia in WKY rats. Heart weight in SHR was normalized to the level found in WKY rats by sympathectomy and demedullation. We conclude that in sympathectomized SHR, the elevated BP was maintained by the adrenal medulla.

Interaction between sympathetic nervous system and adrenal medulla in the control of cardiovascular changes in hypertension

The role of the sympathetic nervous system and adrenal medulla in the development of cardiovascular changes and hypertension was studied in spontaneously hypertensive rats (SHRs), and the results compared with age-matched normotensive Wistar-Kyoto (WKY) rats. Sympathectomy was initiated in newborn rats through daily injection with antiserum to nerve growth factor for 1 week, followed by daily injection with guanethidine for 3 weeks. Removal of the adrenal medulla was carried out in 4-week-old rats after the last guanethidine injection. Such a combination treatment was effective in permanently preventing the development of hypertension in the SHRs, and the blood pressure was maintained at the level of WKY rats. The heart rate of the SHRs and WKY rats was not affected by such treatment. Hypertrophy of the heart and of the vessel wall in the mesenteric arteries was also prevented by such treatment. We conclude that in the SHR, the sympathetic nervous system and the adrenal medulla are essential for the development of cardiovascular changes and hypertension.

Evidence that endogenous beta nerve growth factor is responsible for the collateral sprouting, but not the regeneration, of nociceptive axons in adult rats

A key role has not yet been identified for beta nerve growth factor (NGF) in the growth responses that continue to be expressed in the sensory neurons of adult animals. We have now examined the effects of daily administration to adult rats (and in a few experiments, mice) of antiserum to NGF on (i) the collateral sprouting of undamaged nociceptive nerves that occurs into denervated adjacent skin and (ii) the regeneration of cutaneous sensory axons that occurs after they are damaged. The results were unexpected. All collateral sprouting was prevented and that already in progress was halted; sprouting resumed when treatment was discontinued. In contrast, the reestablishment, and even enlargement, of cutaneous nerve fields by regenerating axons was unaffected by anti-NGF treatment, even after dorsal rhizotomy was done to eliminate any central trophic support. In denervated skin, regenerating and collaterally sprouting axons utilized the same cellular pathways to establish functionally identical fields, thus displaying apparently identical growth behaviors, yet anti-NGF treatment clearly distinguished between them. We suggest that endogenous NGF is responsible for the collateral sprouting of nociceptive axons, probably reflecting an ongoing function of NGF in the regulation of their fields. This demonstration in the adult sensory system of a defined role for NGF in nerve growth could apply to nerve growth factors generally in the adult nervous system. The regeneration, however, of nociceptive axons (and nonnociceptive one) is not dependent on NGF.

Role of mediastinoscopy in pretreatment staging of patients with primary lung cancer

Since the introduction of mediastinoscopy, there has been a great deal of discussion regarding indications for this technique and the significance of positive findings. We undertook this study to determine the role of clinical staging and the value of routine mediastinoscopy in the treatment selection of patients with primary lung cancer. From 1975 to 1983, 1,259 consecutive patients with proven and operable lung cancer underwent preresection mediastinoscopy. Nodes were sampled at three levels, and findings were recorded by location, invasiveness, and histology. There were no operative deaths, but 3 patients had a major complication. Mediastinoscopy was positive in 339 (27%) patients and negative in 920 (73%). In the group with positive findings, 303 patients had no operation because a curative resection was not possible (extranodal metastases, 180; location, 76; histology, 47). No patient survived 5 years, and only 4% survived 2 years. Of the 36 patients considered to have operable disease, 28 underwent resection with a projected 5-year survival of 18%. In the group with negative findings, 89% had a curative resection with a hospital mortality of 3.2% and 5-year survival of 53%. When results of mediastinoscopy were correlated with findings at thoracotomy, the sensitivity of the test was 93% on nodes in the superior mediastinum and the specificity, 100%. This study shows that mediastinoscopy is safe and is an accurate indicator of the presence or absence of tumor in superior mediastinal nodes. If positive nodes are found, a curative resection is generally not possible, thoracotomy is avoided, and the overall survival is low.

Inspiratory muscle strength and body composition in patients receiving total parenteral nutrition therapy

We examined the relationship between inspiratory muscle strength and body composition in 59 patients receiving total parenteral nutrition (TPN). Inspiratory muscle strength was assessed by measuring maximal inspiratory pressure (Pm) after a tidal expiration, with the patient supine and the nose occluded. Body composition was determined by multiple isotope dilution. Body cell mass (BCM) and extracellular mass were estimated by measuring total exchangeable potassium (Ke) and total exchangeable sodium (Nae), respectively; Nae/Ke, an index of the nutritional state, was calculated from these values. The effect of changes in muscle mass was evaluated in 29 of the patients by simultaneous determination of Pm and body composition, prior to and at 2-wk intervals during TPN therapy. The Pm was lower (mean +/- 1 SE:33.5 +/- 2.8 cm H2O) in malnourished patients than in those who were in the normal Nae/Ke range (45.3 +/- 4.8 cm H2O, p less than 0.05). Loss of strength was related to reduction in muscle mass because BCM was also reduced in malnourished patients (15.6 +/- 0.8 kg) when compared to those with normal Nae/Ke (19.3 +/- 0.9 kg), (p less than 0.05), and Pm was positively correlated with BCM (r = 0.27, p less than 0.01). Changes in BCM were accompanied by appropriate changes in Pm during the study period (r = 0.44, p less than 0.01); the majority (21 patients) showed improvement in both BCM and Pm.(ABSTRACT TRUNCATED AT 250 WORDS)