Carry-over fluency induced by extreme prolongations: A new behavioral paradigm.

Extreme prolongations, which can be generated via extreme delayed auditory feedback (DAF) (e.g., 250-500 ms) or mediated cognitively with timing applications (e.g., analog stopwatch) at 2 s per syllable, have long been behavioral techniques used to inhibit stuttering. Some therapies have used this rate solely to establish initial fluency, while others use extremely slowed speech to establish fluency and add other strategic techniques such as easy onsets and diaphragmatic breathing. Extreme prolongations generate effective, efficient, and immediate forward flowing fluent speech, removing the signature behaviors of discrete stuttering (i.e., syllable repetitions and audible and inaudible postural fixations). Prolonged use of extreme prolongations establishes carry-over fluency, which is spontaneous, effortless speech absent of most, if not all, overt and covert manifestations of stuttering. The creation of this immediate fluency and the immense potential of extreme prolongations to generate long periods of carry-over fluency have been overlooked by researchers and clinicians alike. Clinicians depart from these longer prolongation durations as they attempt to achieve the same fluent results at a near normal rate of speech. Clinicians assume they are re-teaching fluency and slow rates will give rise to more normal rates with less control, but without carry-over fluency, controls and cognitive mediation are always needed for the inherently unstable speech systems of persons who stutter to experience fluent speech. The assumption being that the speech system is untenable without some level of cognitive and motoric monitoring that is always necessary. The goal is omnipresent "near normal rate sounding fluency" with continuous mediation via cognitive and motoric processes. This pursuit of "normal sounding fluency" continues despite ever-present relapse. Relapse has become so common that acceptance of stuttering is the new therapy modality because relapse has come to be understood as somewhat inevitable. Researchers and clinicians fail to recognize that immediate amelioration of stuttering and its attendant carry-over fluency are signs of a different pathway to fluency. In this path, clinicians focus on extreme prolongations and the extent of their carry-over. While fluency is automatically generated under these extreme prolongations, the realization is that communication at this rate in routine speaking tasks is not feasible. The perceived solution is a systematic reduction in the duration of these prolongations, which attempts to approximate "normal speech." Typically, the reintroduction of speech at a normalized rate precipitates a laborious style that is undesirable to the person who stutters (PWS) and is discontinued, once departed from the comforts of the clinical setting. The inevitable typically occurs; the well-intentioned therapist instructs the PWS to focus on the techniques while speaking at a rate that is nearest normal speech, but the overlooked extreme prolongations are unlikely to ever be revisited. The foundation of this hypothesis is that the departure from fluency generators (e.g. extreme prolongations) is the cause of regression to the stuttering set point. In turn, we postulate that the continued use of extreme prolongations, as a solitary practice method, will establish and nurture different neural pathways that will create a modality of fluent speech, able to be experienced without cognitive or motoric mediation. This would therefore result in fewer occurrences of stuttering due to a phenomenon called carry-over fluency. Thus, we hypothesize that the use of extreme prolongations fosters neural pathways for fluent speech, which will result in carry-over fluency that does not require mediation by the speaker.

Relaxed rrn expression and amino acid requirement of a Corynebacterium glutamicum rel mutant defective in (p)ppGpp metabolism.

The stringent response in Corynebacterium glutamicum was investigated. Sets of rrn-cat fusions were constructed in their native chromosomal position to examine the effects of amino acid starvation in a rel(+) strain and a Deltarel mutant defective in (p)ppGpp metabolism. The expression of the six rrn operons in the rel(+) control was stringently regulated and reduced to 79% upon induction of amino acid starvation. The Deltarel mutant displayed a relaxed regulation and was unable to reduce the rrn expression under amino acid depletion conditions. In addition, the Deltarel mutant grew more slowly in minimal medium than a rel(+) control. This growth effect was restored by a plasmid-encoded copy of rel or, alternatively, by supplementation of the minimal medium with the amino acid mixture casamino acids. In particular, the Deltarel strain of C. glutamicum displayed a requirement for the amino acids histidine and serine.

Stutter-free and stutter-filled speech signals and their role in stuttering amelioration for English speaking adults.

This study examined the power of an exogenously generated stuttered speech signal on stuttering frequency when compared to an exogenously generated normal speech signal. In addition, we examined the specific components of the second speech signal, which might be responsible for the inducement of fluency in people who stutter. Eight males and two females who stuttered participated in this study. Experiment I involved meaningful speech: normal continuous speech, normal interrupted speech, stuttered continuous speech, and stuttered interrupted speech, whereas Experiment II involved vowels and consonants: /a/, /a-i-u/, /s/, /s-sh-f/. The results indicated that stuttered and normal speech signals were equally effective in reducing stuttering frequency. Further, the vowels were more powerful than consonants in inducing fluency for people who stutter. It is suggested that acoustic manifestations of stuttering, rather than a problem, may be a natural compensatory mechanism to bypass or inhibit the 'involuntary block' at the neural level.

Pantothenate production in Escherichia coli K12 by enhanced expression of the panE gene encoding ketopantoate reductase.

Using gene replacement and transposon Tn5 mutagenesis, an Escherichia coli ilvC panE double mutant completely lacking ketopantoate reductase activity was isolated. This E. coli double mutant was employed to isolate the E. coli panE gene by genetic complementation. The E. coli panE gene is characterized by a 912 bp coding region, which specifies a protein of 303 amino acids with a deduced molecular mass of 33.8 kD. A panE expression plasmid carrying the panE gene under the control of the tac promotor was constructed. Introduction of the panE expression plasmid into E. coli resulted in a threefold increase in ketopantoate reductase activity. It was also shown that the enhanced panE expression in E. coli K12 led to 3.5-fold increase in pantothenate excretion. Pantothenate excretion could even be more enhanced when the growth medium was supplemented with ketopantoate.

Expression of the Corynebacterium glutamicum panD gene encoding L-aspartate-alpha-decarboxylase leads to pantothenate overproduction in Escherichia coli.

The Corynebacterium glutamicum panD gene was identified by functional complementation of an Escherichia coli panD mutant strain. Sequence analysis revealed that the coding region of panD comprises 411 bp and specifies a protein of 136 amino acid residues with a deduced molecular mass of 14.1 kDa. A defined C. glutamicum panD mutant completely lacked L-aspartate-alpha-decarboxylase activity and exhibited beta-alanine auxotrophy. The C. glutamicum panD (panDC. g.) as well as the E. coli panD (panDE.c.) genes were cloned into a bifunctional expression plasmid to allow gene analysis in C. glutamicum as well as in E. coli. The enhanced expression of panDC.g. in C. glutamicum resulted in the formation of two distinct proteins in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, leading to the assumption that the panDC.g. gene product is proteolytically processed into two subunits. By increased expression of panDC.g. in C. glutamicum, the activity of L-aspartate-alpha-decarboxylase was 288-fold increased, whereas the panDE.c. gene resulted only in a 4-fold enhancement. The similar experiment performed in E. coli revealed that panDC.g. achieved a 41-fold increase and that panDE.c. achieved a 3-fold increase of enzyme activity. The effect of the panDC.g. and panDE.c. gene expression in E. coli was studied with a view to pantothenate accumulation. Only by expression of the panDC.g. gene was sufficient beta-alanine produced to abolish its limiting effect on pantothenate production. In cultures expressing the panDE.c. gene, the maximal pantothenate production was still dependent on external beta-alanine supplementation. The enhanced expression of panDC.g. in E. coli yielded the highest amount of pantothenate in the culture medium, with a specific productivity of 140 ng of pantothenate mg (dry weight)-1 h-1.

Quantitative electroencephalogram of posterior cortical areas of fluent and stuttering participants during reading with normal and altered auditory feedback.

In the left and right hemisphere, posterior quantitative electroencephalogram Beta band activity (13.5-25.5 Hz) of seven adult participants who stutter and seven age-matched normal controls was obtained while subjects read text under three experimental conditions of normal auditory feedback, delayed auditory feedback, and frequency-altered feedback. Data were obtained from surface electrodes affixed to the scalp using a commercial electrode cap. Electroencephalogram activity was amplified, band-pass analog-filtered, and then digitized. During nonaltered auditory feedback, stuttering participants displayed Beta band hyperreactivity, with the right temporal-parietal lobe region showing the greatest activity. Under conditions of delayed auditory feedback and frequency-altered auditory feedback, the stuttering participants displayed a decrease in stuttering behavior accompanied by a strong reduction in Beta activity for the posterior-temporal-parietal electrode sites, and the left hemisphere posterior sites evidenced a larger area of reactivity. Such findings suggest than an alteration in the electrical fields of the cortex occurred in the stuttering participants under both conditions, possibly reflecting changes in neurogenerator status or current dipole activity. Further, one could propose that stuttering reflects an anomaly of the sensory-linguistic motor integration wherein each hemisphere generates competing linguistic messages at hyperreactive amplitudes.

Effect of frequency altered feedback and audience size on stuttering.

The effect of frequency altered feedback (FAF) and audience size on stuttering frequency was examined. Nine adults who stutter orally read to audiences of two, four and 15 people under conditions of FAF (one-half octave shift down) and non-altered auditory feedback (NAF). There was no statistically significant effect of audience size on stuttering frequency (p > 0.05). A statistically significant reduction in stuttering frequency was found under FAF relative to NAF (p < 0.5). Collapsed across audience conditions, stuttering frequency was reduced by 74%. These findings suggest that FAF may be useful as a treatment tool.

Stuttering amelioration at various auditory feedback delays and speech rates.

The primary purpose of this study was to determine if the finding of Kalinowski et al. (1993) of dramatic reductions in stuttering under delayed auditory feedback (DAF) at normal and fast speech rates could be replicated. The second purpose was to determine if stuttering frequency is differentially affected by various delays in an attempt to identify the optimal delay for fluency enhancement for both normal and fast speech rates. Fourteen adult stutterers read eight different passages at either a normal or fast speech rate under non-altered auditory feedback (NAF) and DAF with delays of 25, 50 and 75 ms. Results showed that significant fluency enhancement occurred under DAF at both normal and fast speech rates at all DAF settings (p < 0.05). This finding corroborates the notion that a slowed rate of speech is not a necessary antecedent for fluency improvement under conditions of altered auditory feedback. In addition, the results indicated that 50 ms appears to be the shortest delay producing the maximum reduction in stuttering frequency.

[Nutritional evaluation of sweet potato cultivars Ipomea batata (L.) Lam used in bread as partial substitute of wheat flour]. / Evaluación nutricional de cultivares nativos de camote Ipomea batata (L.) Lam, para su utilización en la forma de rallado como sustituto parcial de trigo en panificación.

Four hundred and forty entries of sweet potato tubers from the International Potato Center were evaluated for chemical characteristics related to nutritional value. Dry matter range in the group was 15 to 45g/100g. The native entries DLP 2393, DLP 1120, DLP 2312, DLP 1908 and the foreign RCB 361F were selected for use in bread manufacture. Their average dry matter and crude protein was 38.5 and 9.2% respectively. Sweet potato bread was made replacing 30% of wheat flour with grinded sweet potato tubers. This bread had 11.0% crude protein in dry matter basis which were the same for bread made of wheat flour. There were no differences in organoleptic characteristics or protein quality (Apparent biological value: 37 vs 42%; apparent digestibility: 81 vs 80%; net protein utilization: 33 vs 39%) between sweet potato or full wheat flour breads respectively.

Effects of alterations in auditory feedback and speech rate on stuttering frequency.

This study investigated the effects of altered auditory feedback on stuttering frequency during speech production at two different speech rates, Nine stutterers, who exhibited at least 5% dysfluency during a reading task, served as subjects. They read eight different passages (each 300 syllables in length) while receiving four conditions of auditory feedback: nonaltered, masking, delayed, and frequency altered. For each auditory feedback condition, subjects read at both a normal and a fast rate. Results indicated that stuttering frequency was significantly decreased during conditions of delayed and frequency altered auditory feedback at both speech rates (p < 0.05). These findings refute the notion that a slowed speech rate is necessary for fluency enhancement under conditions of altered auditory feedback. Considering previous research and the results of this study, it is proposed that there may be two interdependent factors that are responsible for fluency enhancement: alteration of auditory feedback and modification of speech production.

Metabolic activity of zinc during late pregnancy and lactation of first-litter gilts and their offspring under low dietary zinc intake.

The metabolism of Zn-65 was studied in littermate gilts fed either low-Zn (10 mg/kg) or Zn-supplemented (50 mg/kg) diets throughout pregnancy and lactation, and dosed with 100 microCi of Zn-65 at 100 days of pregnancy. Zinc-65 appeared earlier in urine of deficient gilts and about the same time after dose in feces of both groups. Total activity and proportion of the dose excreted via feces were higher in supplemented gilts, where as specific activity (SA) of feces was higher in deficient gilts. Excretion of endogenous Zn by supplemented gilts was triple that of deficient gilts whereas true absorption of Zn by deficient gilts was more than 4-fold that of their supplemented littermates. Biological half-life of Zn-65 was 46 d for the control and twice as long in deficient gilts. Total activity and SA of colostrum was higher in deficient gilts. Muscle, followed by liver, retained the highest proportion of the dose in both groups. Proportion of the dose retained in the liver and lungs was higher in control gilts where as Zn-65 retention in brain, heart, lungs and spleen was higher in deficient gilts. Most tissues from deficient gilts showed higher SA. Liver showed the highest Zn-65 concentration in control and lung in low-Zn newborn piglets. At two weeks of age, liver from both groups of piglets showed the highest Zn-65 retention. Proportion of the dose in brain and lungs was higher in deficient piglets. Specific activity of most organs from deficient piglets was higher than that of controls at both ages. Pregnant gilts under low dietary Zn intake made maximum utilization of this mineral by increasing true absorption and reducing endogenous excretion.

Effects of transforming growth factor-beta and IL-1 alpha on prostaglandin synthesis in serum-deprived osteoblastic cells.

We investigated the effects that the combination of IL-1 alpha and transforming growth factor-beta (TGF-beta) had on PGE2 production in a murine clonal osteoblastic cell line MC3T3-E1 and primary rat calvarial osteoblast-like cells. In serum-supplemented medium, IL-1 alpha was a potent stimulator of PGE2 production in MC3T3-E1 cells (50-fold increase with 0.1 ng/ml). TGF-beta (10 ng/ml) had only a small effect alone and no additional effect on IL-1 alpha-induced responses. In serum-deprived MC3T3-E1 cells, PGE2 responses to IL-1 alpha were either absent or markedly reduced. TGF-beta alone had small effects. However, simultaneous addition of TGF-beta with IL-1 alpha to MC3T3-E1 cells partially restored the ability of IL-1 alpha to generate a PGE2 response (10-fold increase in PGE2 with 0.1 ng/ml of both IL-1 alpha and TGF-beta). As with MC3T3-E1 cells, serum-deprived primary fetal rat calvarial osteoblastic cells also did not respond to IL-1 alpha, unless TGF-beta was present in the medium (sixfold increase in PGE2 with 0.1 ng/ml IL-1 alpha and 10 ng/ml TGF-beta). The synergistic effect of TGF-beta and IL-1 alpha was specific for PGE2 responses, because these factors did not synergistically affect cell proliferation, collagen and noncollagen protein synthesis, or alkaline phosphatase activity. The observed synergy was not associated with changes in the steady state cyclooxygenase (PGH synthase) mRNA levels. However, it did correlate with increased release of [3H]arachidonic acid from prelabeled serum-depleted MC3T3-E1 cells. Hence, the synergistic interactions of IL-1 alpha and TGF-beta on PGE2 appear to occur through an increase in the release of arachidonic acid substrate from phospholipid pools. These effects may be important for both normal bone turnover and the responses of bone to inflammatory and immune stimuli.

Tissue composition and trace mineral content of the dam and litter under low dietary zinc intake during gestation and lactation of first-litter gilts.

Dry matter (DM), fat, calcium (Ca), phosphorus (P), zinc (Zn), copper (Cu), iron (Fe) and manganese (Mn) analyses were performed in tissues from gilts and their offspring after receiving either a control (50 mg/kg) or a low-Zn dietary (10 mg/kg) during gestation and lactation. DM and fat content in the body tissues of the dams were not affected by Zn-intake except in the liver and placenta; liver fat was significantly decreased, while placenta fat was significantly increased in the low-Zn gilts. Several tissues of the dams fed the low-Zn diet showed a lower Zn concentration, but liver and bones were the most significantly affected. Liver from these dams compensated with a significant increase in Cu concentration, while placenta, although not affected in its Zn concentration, showed a significant increase in Mn concentration. Overall, at the end of a two week lactation, first-litter gilts showed a significant reduction in total body Zn content, reaching only 65% of the total Zn found in the control gilts. This was compensated for by a significant increase in the total body Cu content, which was 24% greater than in the control group. In spite of the significant reduction of the total body Zn in the dams fed the low-Zn diet, their newborn and two week old piglets showed a significant reduction in Zn concentration in several tissues, of which the liver and bones were mostly affected. At the same time, liver Cu concentration was significantly increased in these piglets. Curiously, there was also observed a consistent increase in Mn concentration in the brain and bones of these piglets. Total body Zn was reduced by more than 40% in newborn piglets from low-Zn dams. There was a significant increase in total body Zn observed from birth to 2 weeks of age in piglets, 58.4 and 53.4 mg for the control and low-Zn group, respectively. This resulted in no significant differences between the 2 experimental groups at the end of 2 weeks of suckling by their respective dams. This indicated that the colostrum and milk was a good source of Zn regardless of the dietary Zn intake of their dams. Total body Cu in piglets at birth was not found to be significantly different in the 2 groups but, by 2 weeks of age, piglets being sucked by low-Zn dams showed a significantly higher Cu content, with an excess of 50% or more of the Cu content found in control piglets.

Nitrogen and trace mineral balance of pregnant gilts under low dietary zinc intake.

Nitrogen (N) and mineral balance studies were carried out in littermate pregnant gilts fed either a zinc (Zn)-deficient basal diet (10 mg/Kg Zn) or a Zn-supplemented diet (50 mg/kg) from day 22 of pregnancy and in open gilts fed the Zn-supplemented diet. Collections were carried out at 60-66 and at 100-106 days of pregnancy. Open controls had N retention similar to that of Zn-restricted and Zn-supplemented gilts in early pregnancy. A trend towards better N utilization due to Zn supplementation was observed in late pregnancy. Pregnant, Zn-supplemented gilts were in negative Zn and copper (Cu) balance in early pregnancy, whereas open controls and Zn-restricted pregnant gilts were in positive Zn and Cu balance. Utilization of Zn and Cu tended to improve in late pregnancy with Zn-restricted gilts retaining somewhat more Zn and Cu than controls. In early pregnancy, Zn-supplemented gilts retained proportions of dietary iron (Fe) similar to that of open controls and twice the proportion retained by Zn-restricted gilts; the latter tended to increase Fe retention in late pregnancy, but Fe retentions by control gilts were still higher. Pregnant gilts were in negative manganese (Mn) balance in early pregnancy whereas open gilts were in positive balance. In late pregnancy both groups tended to improve their Mn economy, being close to Mn equilibrium. Positive Zn balance in Zn-restricted gilts was achieved by marked reduction of fecal Zn. The Zn-saving mechanisms appeared to influence Cu and Fe retention.