The Effects of Different Sources and Modalities of Stuttering Disclosure on Listeners' Perceptions of a Child Who Stutters

INTRODUCTION

Research reveals the clinical efficacy of both verbal and written stuttering disclosure statements provided by a child who stutters (CWS) and his advocates (i.e., mother or teacher) [Lang Speech Hear Serv Sch. 2020 Jul;51(3):745-60 and Lang Speech Hear Serv Sch. 2021 Aug;52(4):1031-1048]. Although existing data reveal that both the source (i.e., self- vs. advocate disclosure) and modality (i.e., verbal or written) of stuttering disclosure yields significant improvements in the perceptions of speech skills and personality characteristics of CWS, there is a paucity of research directly comparing the modality (verbal vs. written) and source (self, mother, teacher) of disclosure statements. Accordingly, this study analyzes listeners' perceptions of a 12-year-old male CWS' speech skills and personal characteristics, as a function of both the source and modality of factual stuttering disclosure statements [Lang Speech Hear Serv Sch. 2020 Jul;51(3):745-60 and Lang Speech Hear Serv Sch. 2021 Aug;52(4):1031-1048].

METHODS

A total of 641 college-aged adults participated in this analysis; study participants reported their perceptions of speech skills and personality characteristics of a 12-year-old CWS as a function of stuttering disclosure. Participants were randomly assigned to view one video containing one of two disclosure modalities (verbal or written), one of three stuttering disclosure source conditions (self-disclosure, mother disclosure, and teacher disclosure), or a no-disclosure control condition. Participants in the control group viewed a brief video of a 12-year-old CWS reciting a short reading passage; participants in the experimental groups viewed their assigned disclosure statement followed by the same video used in the control condition. Immediately following the video, all participants completed a survey quantifying their perceptions of the CWSs relative to his speech skills and personal characteristics.

RESULTS

Results reveal optimal results via verbal self-disclosure and verbal teacher disclosure. A limited number of nominally positive perceptual differences were noted within the written mother disclosure group, while written CWS self-disclosure yielded significantly negative perceptions of the CWS. Overall, verbal disclosures yield far more significant and desirable perceptions of CWS' speech skills and personal characteristics when compared to written stuttering disclosure.

DISCUSSION

Results of this analysis reveal that verbal stuttering disclosure is significantly more effective in improving listeners' perceptions of a CWS, when compared to written stuttering disclosures. Despite the widespread adoption of written communication over digital media (e.g., email and text messages), these data support the notion that face-to-face or video verbal stuttering disclosure provides the most desirable perceptual benefits for CWS. Within verbal stuttering disclosure, verbal self-disclosure appears to be the single best overall disclosure methodology relative to clinical application.

DeepAdversaries: examining the robustness of deep learning models for galaxy morphology classification

With increased adoption of supervised deep learning methods for work with cosmological survey data, the assessment of data perturbation effects (that can naturally occur in the data processing and analysis pipelines) and the development of methods that increase model robustness are increasingly important. In the context of morphological classification of galaxies, we study the effects of perturbations in imaging data. In particular, we examine the consequences of using neural networks when training on baseline data and testing on perturbed data. We consider perturbations associated with two primary sources: (a) increased observational noise as represented by higher levels of Poisson noise and (b) data processing noise incurred by steps such as image compression or telescope errors as represented by one-pixel adversarial attacks. We also test the efficacy of domain adaptation techniques in mitigating the perturbation-driven errors. We use classification accuracy, latent space visualizations, and latent space distance to assess model robustness in the face of these perturbations. For deep learning models without domain adaptation, we find that processing pixel-level errors easily flip the classification into an incorrect class and that higher observational noise makes the model trained on low-noise data unable to classify galaxy morphologies. On the other hand, we show that training with domain adaptation improves model robustness and mitigates the effects of these perturbations, improving the classification accuracy up to 23% on data with higher observational noise. Domain adaptation also increases up to a factor of ≈ 2.3 the latent space distance between the baseline and the incorrectly classified one-pixel perturbed image, making the model more robust to inadvertent perturbations. Successful development and implementation of methods that increase model robustness in astronomical survey pipelines will help pave the way for many more uses of deep learning for astronomy.

Identification of Racial Inequities in Access to Specialized Inpatient Heart Failure Care at an Academic Medical Center

BACKGROUND

Racial inequities for patients with heart failure (HF) have been widely documented. HF patients who receive cardiology care during a hospital admission have better outcomes. It is unknown whether there are differences in admission to a cardiology or general medicine service by race. This study examined the relationship between race and admission service, and its effect on 30-day readmission and mortality Methods: We performed a retrospective cohort study from September 2008 to November 2017 at a single large urban academic referral center of all patients self-referred to the emergency department and admitted to either the cardiology or general medicine service with a principal diagnosis of HF, who self-identified as white, black, or Latinx. We used multivariable generalized estimating equation models to assess the relationship between race and admission to the cardiology service. We used Cox regression to assess the association between race, admission service, and 30-day readmission and mortality.

RESULTS

Among 1967 unique patients (66.7% white, 23.6% black, and 9.7% Latinx), black and Latinx patients had lower rates of admission to the cardiology service than white patients (adjusted rate ratio, 0.91; 95% CI, 0.84-0.98, for black; adjusted rate ratio, 0.83; 95% CI, 0.72-0.97 for Latinx). Female sex and age >75 years were also independently associated with lower rates of admission to the cardiology service. Admission to the cardiology service was independently associated with decreased readmission within 30 days, independent of race.

CONCLUSIONS

Black and Latinx patients were less likely to be admitted to cardiology for HF care. This inequity may, in part, drive racial inequities in HF outcomes.

DEEP BIOSPHERE. Exploring deep microbial life in coal-bearing sediment down to ~2.5 km below the ocean floor

Microbial life inhabits deeply buried marine sediments, but the extent of this vast ecosystem remains poorly constrained. Here we provide evidence for the existence of microbial communities in ~40° to 60°C sediment associated with lignite coal beds at ~1.5 to 2.5 km below the seafloor in the Pacific Ocean off Japan. Microbial methanogenesis was indicated by the isotopic compositions of methane and carbon dioxide, biomarkers, cultivation data, and gas compositions. Concentrations of indigenous microbial cells below 1.5 km ranged from <10 to ~10(4) cells cm(-3). Peak concentrations occurred in lignite layers, where communities differed markedly from shallower subseafloor communities and instead resembled organotrophic communities in forest soils. This suggests that terrigenous sediments retain indigenous community members tens of millions of years after burial in the seabed.

Response to "Intensive stuttering modification therapy: a multidimensional assessment of treatment outcomes," by Blomgren, Roy, Callister, and Merrill (2005)

PURPOSE

M. Blomgren, N. Roy, T. Callister, and R. Merrill (2005) used a multidimensional approach to evaluate treatment efficacy for the Successful Stuttering Management Program. While the article acknowledged that the treatment program under evaluation does not target a reduction in stuttering frequency, Blomgren and colleagues concluded that the therapy "was ineffective in producing durable reductions of core stuttering behaviors, such as stuttering frequency and severity." In this response, it is suggested that Blomgren et al. used inappropriate treatment efficacy measures relative to the therapy program under evaluation, subsequently making the study's data difficult to interpret.

CONCLUSION

It is suggested that stuttering treatment efficacy measures include client-reported treatment satisfaction data, efficacy measures relative to the goals and values of the therapy approach being evaluated, and data relative to the documented values and priorities of those within the stuttering population.

A program design to promote clinical judgment

This article describes a unique continuing education program designed to enhance critical thinking, clinical judgment, and communication skills of practicing nurses in an acute care setting. The program design and implementation strategies are described in detail. The authors include specific examples for those who want to develop a similar program to improve the practice of registered nurses in the acute care setting.

Dating of pore waters with (129)I: relevance for the origin of marine gas hydrates

Pore waters associated with gas hydrates at Blake Ridge in the Atlantic Ocean were dated by measuring their iodine-129/iodine ratios. Samples collected from sediments with ages between 1.8 and 6 million years ago consistently yield ages around 55 million years ago. These ages, together with the strong iodine enrichment observed in the pore waters, suggest that the origin of iodine is related to organic material of early Tertiary age, which probably is also the source of the methane in the gas hydrates at this location.

Inducement of fluent speech in persons who stutter via visual choral speech

A novel phenomenon of fluency enhancement via visual gestures of speech in the absence of traditional auditory feedback is reported herein. The effect on visual choral speech on stuttering frequency was investigated. Ten participants who stuttered recited memorized text aloud under two conditions. In a visual choral speech (VCS) condition participants were instructed to focus their gaze on the face, lips and jaw of a research assistant who 'silently mouthed' the text in unison. In a control condition, participants recited memorized text to the research assistant who sat motionless. A statistically significant (P=0.0025) reduction of approximately 80% in stuttering frequency was observed in the VCS condition. As visual linguistic cues are sufficient to activate the auditory cortex, one may speculate that VCS induces fluency in a similar yet undetermined manner as altered auditory feedback does.

Effects of aerosolized synthetic surfactant, atovaquone, and the combination of these on murine Pneumocystis carinii pneumonia

An immunosuppressed rat model was used to determine the pharmacokinetics of aerosolized atovaquone (administered with and without a synthetic surfactant) and to evaluate the efficacy of inhaled atovaquone in the prevention and treatment of Pneumocystis carinii pneumonia (PCP). After a single dose by aerosol, mean peak concentrations of atovaquone averaged 52 microg/mL in plasma and 31 microg/g in lungs of rats infected with P. carinii. When atovaquone was combined with surfactant, mean peak concentrations of 94 microg/mL in plasma and 51 microg/g in lung were achieved. Aerosolized synthetic surfactant alone significantly increased survival of rats with PCP and, when combined with atovaquone, increased plasma and lung concentrations of the drug and eradication of the organism.

The anatomy of an OPTI: Part 2. The CORE system. Ohio Osteopathic Hospital Association. Ohio Association of Osteopathic Medical Directors. Ohio Osteopathic Association

In July 1995, the American Osteopathic Association (AOA) Board of Trustees passed new regulations regarding the accreditation of osteopathic graduate medical education (GME) by establishing the Osteopathic Postdoctoral Training Institutions (OPTI) system. This system must be phased in by July 1999. The principal changes resulting from the OPTI system include establishing requirements for college cosponsorship of GME programs and for the number of residency programs, interns, and residents to be trained by the OPTI. In essence, OPTI is an osteopathic acronym for consortium. Each OPTI must include at least one college of osteopathic medicine (COM) and one AOA-accredited hospital. The OPTIs will be subject to interval AOA inspections and will be required to demonstrate a governing system, mission statement, organizational structure, and the presence of faculty development programs. The first article in this two-part series, published in the October JAOA, provided a general blueprint for OPTI building and presented both positive and negative issues germane to the formation of OPTIs. Part 2 reinforces the considerations outlined in Part 1 by describing the formation of a large OPTI--the Ohio University College of Osteopathic Medicine (OU-COM) Centers of Osteopathic Regional Education (CORE) system. Key features are described, including the mission statement, organizational structure, committee system, governance, GME programs, operations, and budget.

Medicaid primary care services in New York State: partial capitation vs full capitation

BACKGROUND

Forty-nine states have applied to the Health Care Financing Administration for waivers to allow special program development for Medicaid recipients. In an effort to identify issues relevant to making the transition of its entire Medicaid population into a capitation model, New York State has encouraged the development of partial capitation and full capitation models. This paper is a critical description analysis of a 1-year experience, utilizing data provided by the New York State Department of Social Services.

METHODS

Data collected by the New York State Department of Social Services were used to compare the costs for matched cohorts enrolled in partial capitation programs in which the primary care physician is paid a monthly fee to provide ambulatory primary care for Medicaid recipients; and full capitation programs in which a health maintenance organization (HMO) or a hospital-based prepaid health services program (PHSP) is paid a more encompassing monthly fee to provide a larger range of services, including inpatient, outpatient, and specialty care.

RESULTS

Partial capitation programs were reported to save the state 38% compared with a matched control group enrolled in traditional, fee-for-service Medicaid (P<.05), and offered greater savings than HMOs and PHSPs (P=NS). The HMOs and PHSPs saved the state 9.3% and 16.8%, respectively, compared with traditional enrollment. Quality measures and patient satisfaction for partial and full capitation programs were equivalent.

CONCLUSIONS

These data suggest that New York State primary care physicians who participated in programs that reimburse a prepaid monthly fee for outpatient primary care services achieved savings comparable to those of HMOs. A partial capitation primary care model may offer an affordable and more flexible alternative to full-service HMOs in caring for Medicaid recipients, especially in communities with limited HMO penetration.

Aerosol characteristics of 99mTc-pentetic acid (DTPA) and synthetic surfactant (Exosurf)

This study evaluated the feasibility of using 99mTc-pentetic acid (DTPA) as a radioactive tracer for aerosolized synthetic surfactant (DPPC, cetyl alcohol, tyloxapol). The 99mTc-DTPA was admixed with surfactant and aerosolized using a nebulizer system interfaced to a ventilator with a cascade impactor attached to the endotracheal tube. Particle size distribution for DPPC, cetyl alcohol, and 99mTc-DTPA were almost identical during the 0- to 15-, 15- to 30-, and 0- to 30-min collection periods. Tyloxapol exhibited a unique distribution pattern with increased deposition in large (> 10 microns) and small (0.65 to 1.1 microns) particles. The mass median aerodynamic diameter for all aerosolized components was in the respirable range of 2.1 to 2.5 microns. A mixture of 99mTc-DTPA with synthetic surfactant appears to be a reasonable method to evaluate surfactant deposition.

Impact of increasing calcium in the diet on nutrient consumption, plasma lipids, and lipoproteins in humans

This study examined the feasibility of increasing food-derived calcium to 1500 mg/d and the impact of this change on plasma lipids and nutrient consumption in hypertensive (n = 130) and normotensive (n = 196) participants. Three interventions were applied in a randomized, parallel, placebo-controlled fashion: 1) counseling to increase dietary calcium through food consumption to 1500 mg/d (n = 106), 2) a 1000-mg/d calcium supplement (n = 109), or 3) placebo (n = 111). Plasma lipids were measured before and after 12 wk of intervention whereas nutrient intake was monitored throughout the study. At baseline, hypertensive patients reported lower intakes of carbohydrates, calcium, magnesium, phosphorus, potassium, iron, vitamin D, thiamin, and riboflavin (all P < 0.05). They also had lower HDL (P = 0.014) and higher LDL (P < 0.05) compared with normotensive subjects. During intervention, calcium, magnesium, phosphorus, potassium, thiamin, riboflavin, and vitamins C and D increased (P < 0.01) in the group receiving food calcium but not in the placebo or supplement groups. No changes occurred in plasma lipids or lipoproteins after 12 wk of intervention.

Distribution of dopamine- and cAMP-dependent phosphoprotein (DARPP-32) in the developing and mature kidney

DARPP-32 is a dopamine- and cAMP-regulated inhibitor of protein phosphatase-1 (PP-1). Dopamine and DARPP-32 regulate sodium reabsorption in renal tubules by inhibiting the activity of Na+,K(+)-ATPase. We here report the pre- and postnatal distributions of DARPP-32 in the kidney as demonstrated by immunoblotting and immunohistochemistry. With immunoblotting we examined the abundance of DARPP-32 and the functionally similar but more widespread inhibitor of PP-1, inhibitor-1 (I-1). We compared their relative abundance in the renal cortex, renal medulla and neostriatum from the brain, where DARPP-32 is greatly enriched. DARPP-32 levels in the adult rat were fourfold higher in the neostriatum than in the renal medulla and 13-fold higher than in the renal cortex. I-1 levels were approximately the same in the neostriatum and in the renal medulla and 2.5-fold higher in neostriatum than in the renal cortex. Between postnatal day 10 (PN10) and 40 (PN40) DARPP-32 abundance increased 1.3-fold in the neostriatum, 1.4-fold in the renal cortex and sixfold in the medulla. The abundance of I-1 did not increase in the striatum from PN10 to PN40 but increased 1.5-fold in the renal cortex and threefold in the renal medulla. Thus, during the time of maturation of tubular transport function, the levels of both PP-1 inhibitors increased in the kidney, the largest increase being found in the renal medulla. With immunohistochemistry strong DARPP-32-like-immunoreactivity (DARPP-32-LI) was detected in the ureteral buds from gestational day 18 and up to postnatal day 8 when nephrogenesis was completed.(ABSTRACT TRUNCATED AT 250 WORDS)

Catheter-related complications in 35 children and adolescents with gastrointestinal disease on home parenteral nutrition

A 7-year experience with home parenteral nutrition (HPN) in 35 children and adolescents suffering from severe gastrointestinal diseases is reported. The average duration of HPN was 577 days with a mean of 2.9 catheters per patients. There was a total of 82 episodes of proven catheter-related sepsis, an average of 1.5 septic episodes per patient year. In about half of these instances, the catheter had to be removed. Coagulase-negative and -positive staphylococci were the most common organisms isolated. All four Candida infections led to removal of the catheter. Children requiring HPN from early infancy had a higher frequency of catheter-related infections than those started on HPN after the first year of life. In four cases, clinically significant thrombotic complications occurred. The results suggest that even under optimal conditions of catheter placement and with extensive education in aseptic catheter handling, infection is still relatively common in children receiving HPN. However, there was no mortality related to this complication.

High-frequency oscillatory ventilation and extracorporeal membrane oxygenation for the treatment of acute neonatal respiratory failure

Forty-six (92%) outborn and four (8%) inborn term or near-term neonates were admitted for extracorporeal membrane oxygenation (ECMO) treatment to a neonatal intensive care unit between July 1, 1985, and November 1, 1987. All infants had PAO2-PaO2 greater than or equal to 600 mm Hg in spite of aggressive conventional ventilatory and pharmacologic therapy. All patients were offered rescue treatment with high-frequency oscillatory ventilation (HFOV), and only if there was no improvement in PAO2-PaO2 with HFOV were infants treated using ECMO. Four patients died before receiving an adequate trial of HFOV and before emergency ECMO support could be initiated; 21 patients, all of whom survived to hospital discharge, responded to HFOV; 25 patients ultimately required ECMO therapy for cardiopulmonary support, with 22 (88%) surviving to discharge. Neonates responding to HFOV were of slightly younger gestational age (38 +/- 2 weeks vs 40 +/- 2 weeks, mean +/- SD; P less than .001) and more frequently had clinical evidence of pneumonia (11 of 21 vs 2 of 25; P less than .002). There was no statistically significant difference in outcome with respect to the number of ventilator days, hospital days, or survival between patients responding to HFOV and patients who required ECMO. Morbidity was increased in ECMO patients, with bleeding abnormalities, seizures, and renal failure occurring more frequently than in HFOV-treated infants. Overall, 92% (46 of 50) of the patients were treated with a staged protocol using HFOV before ECMO. A total of 46% (21 of 46) responded to HFOV treatment alone and did not require ECMO therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Nitric oxide and nitrous oxide production and cycling during dissimilatory nitrite reduction by Pseudomonas perfectomarina

The denitrifier Pseudomonas perfectomarina reduced nitrite under conditions of kinetic competition between cells and gas sparging for extracellular dissolved nitric and nitrous oxides, NOaq and N2Oaq, in a chemically defined marine medium. Time courses of nitrite reduction and NOg and N2Og alpha removal were integrated to give NOg and N2Og yields. At high sparging rates, the NOg yield was greater than 50% of nitrite-N reduced, and the yield of NOg + N2Og was approximately 75%. Hence interrupted denitrification yields NOaq and N2Oaq as major products. The yields varied with sparging rates in agreement with a quantitative model of denitrification (Betlach, M. P., and Tiedje, J.M. (1981) Appl. Environ. Microbiol. 42, 1074-1084) that applies simplified Michaelis-Menten kinetics to NO2-----NOaq----N2Oaq----N2. The fit gave an estimate of the maximum scavengeable NOaq yield of 73 +/- 8% of nitrite-N. Thus a minor path independent of NOaq is also required. The fit of the model to data at lower sparging rates, where normal denitrification products predominate, implies that the extracellular NOaq pool yield is independent of gas sparging rate. Thus in P. perfectomarina NOaq and N2Oaq are intermediates, or facilely equilibrate with true intermediates, during complete denitrification. The recovery of most nitrite-N as NO and/or N2O under perturbed conditions is not an artifact of irreversible product removal, but an attribute of denitrification in this species, and most probably it is characteristic of denitrification in other species as well.

Hypothalamic action of delta-9-tetrahydrocannabinol to inhibit the release of prolactin and growth hormone in the rat

The site of action of delta-9-tetrahydrocannabinol (THC) to inhibit the release of prolactin (PRL) and growth hormone (GH) was examined by in vivo and in vitro experiments. In conscious freely moving animals bearing implanted third ventricular (3V) and external jugular cannulae, THC or the diluent was microinjected into the 3V and blood samples were removed to determine the effect on plasma PRL and GH. Both the 0.4- and 4-micrograms dose injected intraventricularly resulted in a suppression of PRL and GH release as indicated by declines in plasma levels within 40-80 min which were highly significant statistically but not dose-related. The higher dose evoked a pulse of GH and/or PRL in most animals which preceded the lowering of hormonal levels. In the in vitro experiments dipersed anterior pituitary cells were incubated with 5 x 10(-8) or 5 x 10(-9)M THC or the diluent for 5 days. Fresh culture medium was added to the cells after 3 days and the cells cultured for an additional 2 days. After this period, the cells were incubated for an additional 2 h in culture medium with or without THC plus a near maximal dose of thyrotropin-releasing hormone and GH-releasing factor (50 and 10 ng/ml, respectively) or the diluent to evaluate the response of PRL and GH release, respectively. Neither dose of THC altered the release or storage of the two hormones during culture or affected the response to the releasing hormones which is suggestive that there is no direct effect of THC on either GH or PRL release.(ABSTRACT TRUNCATED AT 250 WORDS)

An experience with epidural morphine in lumbar surgery patients

A chart review of the patients who received epidural morphine for lumbar surgery during the first year of implementation of the procedure was conducted. This article reviews the pharmacology and side effects of epidural morphine, describes the procedure of administering epidural morphine, discusses side effects and technical problems encountered, and presents implications for nursing practice.

5,6-Epoxyeicosatrienoic acid mobilizes Ca2+ in anterior pituitary cells

Luteinizing hormone releasing hormone stimulates the concomitant release of luteinizing hormone and 45Ca2+ from prelabeled anterior pituitary cells. Indomethacin (10 microM) and nordihydroguaiaretic acid (10 microM) had no effect on the luteinizing hormone releasing hormone-stimulated release of either luteinizing hormone or 45Ca2+. Eicosatetraynoic acid (10 microM) blocked both luteinizing hormone releasing hormone-stimulated luteinizing hormone secretion and luteinizing hormone releasing hormone-stimulated 45Ca2+ efflux. 5,6-Epoxyeicosatrienoic acid stimulated both luteinizing hormone secretion and 45Ca2+ efflux from anterior pituitary cells. Additionally, 5,6-epoxyeicosatrienoic acid closely mimics the ability of luteinizing hormone releasing hormone to increase intracellular free calcium. These results are consistent with the hypothesis that 5,6-EET alters calcium homeostasis in a manner similar to that observed during luteinizing hormone releasing hormone stimulation of luteinizing hormone release.

Ab initio studies of the antiviral drug 1-(2-fluoro-2-deoxy-beta-D-arabinofuranosyl) thymine

The antiviral drug 1-(2-fluoro-2-deoxy-beta-D-arabinofuranosyl) thymine (FMAU) exhibits a high therapeutic index against a number of herpesviruses. As with other drugs which are nucleoside analogs, such as 1-(2-fluoro-2-deoxy-beta-D-arabinofuranosyl)-5-iodocytosine and others, the activity seems to be strongly related to the presence of a fluorine atom in the sugar moiety, in the arabino position. Theoretical calculations, using quantum-chemical methods, are used to elucidate the role of the fluorine in the arabino position and to provide information about the sugar puckering. The results seem to indicate that the fluorine atom prevents the rotation of the base around the sugar-base bond, locking it into an anti structure (Fig. 2,A3) which might be related to its exposure to enzymatic attack. The sugar study confirms the endo position (above the plane) of the C'2 carbon as opposed to the endo position of the C'3 carbon.

Self-consistent-field comparative studies of some nitrosoureas and nitrosamides

Ab initio (self-consistent-field) calculations are performed in order to obtain information about the most stable conformers of methylnitrosourea, chloroethyl nitrosourea, and their corresponding amides (methylnitrosamide and chloroethylnitrosamide). While nitrosoureas are found to exhibit a Z-conformation, nitrosamides are found to exhibit an E-conformation, a difference which could account for their different stabilities toward in vivo decomposition and which could, as such, influence their carcinostatic activity.

Action of thyrotropin-releasing hormone on mammotrophs and thyrotrophs

Anterior pituitary cells from 15-day female rats were separated by unit gravity sedimentation into four populations (designated regions I-IV) based on the profile of cell distribution and the resulting content of radioimmunoassayable (RIA) hormones. The cells in regions II and IV released thyrotropin (TSH) in response to thyrotropin-releasing hormone (TRH, 5 ng/ml); however, those in region IV released only approximately 5% of their RIA content, whereas those in region II released approximately 26% in response to the same stimulus. Concomitant elevation of cAMP and of cGMP occurred in region II cells but only cGMP was elevated in region IV cells. Mammotrophs were localized in region III. They responded to TRH by releasing prolactin (PRL) and exhibiting increased cAMP content. These data provide support for the existence of two functionally distinct populations of thyrotrophs in 15-day-old female rats. The data also imply that cAMP is involved in TRH induced PRL release, whereas cGMP is involved in TRH-induced TSH release.

A self-consistent field molecular orbital study of hydroxyguanidine

Theoretical self-consistent field molecular orbital calculations indicate that the hydroxyguanidinium ion can dissociate in alkaline or neutral medium by the loss of the hydroxyl proton, leading to the formation of a strong nucleophilic agent which can attack a positive receptor in enzymes, acting in this way as an antitumor and an antiviral agent. Geometry optimization, total energies, and net atomic charges are calculated using a Gaussian basis set for the hydroxyguanidinium ion and its conjugate bases.

Gonadotropin release and cyclic nucleotides: evidence for luteinizing hormone-releasing hormone-induced elevation of guanosine 3',5'-monophosphate levels in gonadotrophs

To investigate the participation of cyclic nucleotides in LHRH-mediated gonadotropin release, cells from the anterior pituitaries of 15-day-old female rats were fractionated on an albumin gradient by sedimentation at unit gravity. gonadotrophs and somatotrophs were detected in the fractions by histology and RIA of hormone content, then the cells were pooled into three subpopulations and cultured overnight. The effect of LHRH on hormone release and cyclic nucleotide content was examined by incubation in the presence or absence of the releasing hormone. After 60 min, LHRH (5 nM) had induced a 5- to 6-fold increase in LH release only from the cells in the subpopulation which was enriched in gonadotrophs. At no time did LHRH influence cAMP levels in any of the cells; however, the cGMP content of the cells in the gonadotroph-containing pool rose to twice that in the controls after only 15 min in the presence of LHRH. The increase in cGMP concentration in the cells was at or near maximum by the time of the initial sampling; however, LH continued to accumulate in the medium over the entire test period. These observations support the view that cGMP is involved in the action of LHRH.

In vitro stimulation of prolactin release by vasoactive intestinal peptide

The effect of vasoactive intestinal peptide (VIP) on anterior pituitary hormone release was examined in a variety of in vitro preparations. Synthetic VIP was capable of stimulating increased prolactin (PRL) release from male rat hemipituitaries in doses as low as 10-9M only when the enzyme inhibitor bacitracin was present in the incubation medium. Natural porcine VIP was similarly capable of stimulating PRL release, but only at higher doses (10-6M). Additionally, synthetic VIP was capable of stimulating PRL release from dispersed anterior pituitary cells harvested from adult male and lactating female rats and from an enriched population of lactotrophs obtained by unit gravity sedimentation of similar dispersed cells from infantile female rats. No effect of VIP on luteinizing hormone, growth hormone or thyroid stimulating hormone release was seen. These findings taken in concert with the presence of VIP in the hypothalamus, pituitary and hypophyseal portal plasma of the rat suggest a physiological role for VIP in the control of PRL secretion.

Chromatographic and biologic analysis of ME and OVLT LHRH

The luteinizing hormone (LH)-releasing activities a pooled rat organum vasculosum lamina terminalis (OVLT) and median eminence (ME) tissues were evaluated for chromatographic and biologic similarity and compared to those of synthetic decapeptide LH-releasing hormone (LHRH). The LHRH detected in these extracts appeared similar chromatographically (Sephadex G-25) to synthetic LHRH. These extracts, as well as synthetic LHRH, were also capable of stimulating dose dependent gonadotropin release form cultures rat gonadotrophs. These findings suggest a physiological role of the LHRH present in the rat OVLT in the control of gonadotropin secretion.

A possible role for cyclic GMP in mediating the effect of luteinizing hormone releasing hormone on gonadotropin release in dispersed pituitary cells of the female rat

In continuing studies on cyclic nucleotide involvement in the regulation of gonadotropin release, we have measured the cyclic nucleotide content and rate of LH and FSH release during stimulation by LHRH of dispersed overnight cultured cells from the pituitaries of adult female rats. The minimal effective concentration of LHRH was 0.1 nM and half maximal stimulation of gonadotropin release was observed in the presence of 1.0 nM LHRH. Significant release of both LH and FSH was detectable after only 10 min in the presence of 5 nM LHRH. The presence of fetal calf serum (FCS) in the overnight culture medium increased basal cGMP levels significantly, whereas horse serum (HS) had no effect, therefore all experiments were conducted on cells cultured in the presence of HS. Treatment of the cultured cells with the phosphodiesterase inhibitors theophylline (TH) or isobutyl-methyl-xanthine (MIX) revealed a preferential stimulatory effect of TH on basal cAMP levels and of MIX on cGMP levels. Throughout these experiments, LHRH had no effect on cAMP levels. In the presence of MIX, concentrations of the releasing hormone as low as 1 nM induced a significant rise in the level of cGMP whereas in its absence, cGMP levels appeared to be unchanged by LHRH. The increase was detectable after 10 min of incubation. MIX alone slightly increased LH and FSH release and significantly potentiated the response of the cells to increasing doses of LHRH up to, but not beyond, 10 nM. The data support the possibility that cGMP may be involved in the mechanism of action of LHRH.

Functional heterogeneity in somatotrophs isolated from the rat anterior pituitary

Somatotrophs in suspensions of anterior pituitary cells from adult male rats can be separated into 2 fractions by density gradient centrifugation. In addition to their different densities, somatotrophs in these 2 fractions can be distinguished morphologically by their staining characteristics and ultrastructure. Somatotrophs of lesser density (type I; approximately 1.068 g/cm3) have fewer secretory granules and a more extensive Golgi apparatus than the somatotrophs of greater density (type II; approximately 1.073 g/cm3). Responsiveness of type I and type II cells to secretory agents (i.e., dibutyryl cyclic adenosine monophosphate, somatostatin, thyroxine, and hydrocortisone) was evaluated by GH radioimmunoassay. Type I cells were consistently more responsive (% GH release) than type II cells. During 7 days in culture, type I cells produced more (approximately 200%) GH than they initially contained, whereas type II cells did not show evidence of increased GH production. Hydrocortisone significantly stimulated GH production in type I, but not type II cells. These results support the hypothesis that at least 2 functionally distinct populations of somatotrophs are present in the anterior pituitary gland of the adult male rat.

Experimental and clinical therapy of diabetes by transplantation

Prevention, delay, or reversal of the microvascular complications of diabetes is the ultimate goal of pancreatic islet cell transplantation. Advances in surgical techniques and in islet isolation procedures have made the achievement of this goal a practical possibility. Microvascular lesions have indeed been prevented and even reversed in successful islet cell transplantation experiments in rats. Successful application of pancreatic islet cell transplantation in the human now awaits the development of effective suppression of rejection.

A short method for the isolation of somatotrophs from the rat pituitary gland

Application of a density gradient centrifugation procedure for the isolation of somatotrophs from dispersed rat anterior pituitary cells is described. Two sequential discontinuous gradients of bovine serum albumin are used to enrich the somatotroph population from a frequency of 38% in the initial cell suspension to a final purity of 85%. The isolated somatotrophs retain both histochemical and ultrastructural integrity throughout the isolation procedure. The isolated somatotrophs also release immunoassayable growth hormone when incubated with 6 mM dibutyryl 3',5'-cyclic AMP. The method offers the advantages of being both simple and short.