Biomedical subjects

J Sundberg

Publications and source records attributed to J Sundberg.

At least 19 recordsLinked to original sources

PubMed2001

Level and center frequency of the singer's formant.

The "singer's formant" is a prominent spectrum envelope peak near 3 kHz, typically found in voiced sounds produced by classical operatic singers. According to previous research, it is mainly a resonatory phenomenon produced by a clustering of formants 3, 4, and 5. Its level relative to the first formant peak varies depending on vowel, vocal loudness, and other factors. Its dependence on vowel formant frequencies is examined. Applying the acoustic theory of voice production, the level difference between the first and third formant is calulated for some standard vowels. The difference between observed and calculated levels is determined for various voices. It is found to vary considerably more between vowels sung by professional singers than by untrained voices. The center frequency of the singer's formant as determined from long-term spectrum analysis of commercial recordings is found to increase slightly with the pitch range of the voice classification.

Female↗

PubMed2001

Consistency of inhalatory breathing patterns in professional operatic singers.

Respiratory behavior is generally considered important to voice function, the assumption being that it affects the voice source. Accurate and consistent control of the voice source is particularly important in professional operatic singing. An erratic behavior of a factor influencing voice production is incompatible with a well-controlled vocal behavior. We analyzed the consistency of inhalatory breathing patterns during singing in five professional operatic singers, using the same material as in a previous investigation of phonatory breathing patterns. Rib cage (RC) and abdominal wall (AW) movements were recorded by respiratory inductive plethysmography. Consistency was analyzed in terms of the mean correlation between three takes of ten musical phrases. Results revealed a high consistency in lung volume (LV) change and RC movements in all singers and in AW movements in three singers. Consistency across different phrases was slightly lower. The results are compatible with the idea that inhalatory behavior is important to voice source in singing. A high correlation between LV change and RC movement was found in all singers and between LV change and AW movement in three. The contribution to LV change from RC was greater than that from AW in all singers.

Adult↗

PubMed2001

Voice source differences between falsetto and modal registers in counter tenors, tenors and baritones.

Vocal registers are generally assumed to be associated with the voice source, i.e. the pulsating transglottal airflow. The waveform of this airflow was analysed by inverse filtering in professional singers, four counter tenors, five tenors, and four baritones singing the syllable [pae:] in soft, middle, and loud voice in modal and falsetto/counter tenor register. Subglottal pressure, estimated from the intra-oral pressure during the occlusion for the consonant [p], closed quotient, relative glottal leakage, and the relative level of the fundamental were analysed. The counter tenors used comparatively low subglottal pressures and mostly showed a closed phase in their flow glottogram waveform. For a given value of the closed quotient, the fundamental tended to be stronger in falsetto than in modal register. The observed voice source differences between the registers seem related to a greater vocal fold thickness in modal than in falsetto register.

Adult↗

PubMed2000

Perceptual and acoustic analysis of vocal registers in 10-year-old children.

Register transitions were identified by a group of five experts on child voices in recordings of 15 10-year-old children who sustained the vowel [a:] at different pitches throughout their vocal range. Two had mutational voices, seven had deviant voices and six were controls with normal voices. The control group had one register transition at a mean fundamental frequency of 511 Hz, or about 25% higher than in adult voices. This difference between adult and child voices may be because of the difference in trachea length, as proposed by Titze (J. Voice 1988; 3: 183-194). Children with either functional or physiological voice deviations exhibited a transition at a mean frequency of 417 Hz. A second transition was found in four voices at a mean frequency of 902 Hz. No correlation was found between the occurrence of register transitions and discontinuities in the upper and lower voice range profile contours.

Child↗

PubMed2000

The C3H/HeJBir mouse model: a high susceptibility phenotype for colitis.

C3H/HeJBir is a substrain of C3H/HeJ mice that was generated by selective breeding for the phenotype of spontaneous colitis. These mice show increased B cell and T cell reactivity to antigens of the enteric bacterial flora. CD4+ T cells from this strain cause colitis, when activated by enteric bacterial antigens and transferred to histocompatible severe combined immunodeficient recipients. The expression of the disease phenotype of spontaneous colitis is greatly influenced by housing conditions and probably requires an immunostimulatory enteric flora. This strain seems to carry multiple susceptibility genes for colitis as does the parental C3H/HeJ strain; the genes involved are being mapped. This strain represents a high susceptibility phenotype for colitis that is providing insight into the interactions among immune, environmental and genetic factors that can result in IBD.

Animals↗

PubMed1999

Protein binding of mercury in milk and plasma from mice and man--a comparison between methylmercury and inorganic mercury.

Inorganic mercury has previously been shown to be excreted to milk from plasma to a higher extent than methylmercury. Protein binding of mercury as methylmercury and inorganic mercury in whey and plasma from mouse and man was studied in order to get a better understanding of the transport of mercury into milk. Mice were administered a single i.v. dose of 0.25 mg Hg/kg body weight labelled with (CH3)203HgCl or 203HgCl2, resulting in 11 ng Hg/g milk and 38 ng Hg/g milk after 1 h, respectively. Milk and plasma from mice and man were also incubated with the respective radiolabelled compound (150 ng Hg/g milk or plasma). Casein, fat and whey fractions in milk from methylmercury treated mice were found to contain 11, 39 and 34%, respectively, and from inorganic mercury treated mice 31, 15 and 41%, respectively, of the total amount of mercury in milk. Serum albumin was a major mercury binding protein in whey and plasma from mice for both methylmercury and inorganic mercury, as demonstrated by FPLC gel filtration and anion-exchange chromatography and further characterised by SDS-PAGE for whey. In addition, anion-exchange chromatography indicated that inorganic mercury, but not methylmercury, in whey from mouse milk formed a dimer of serum albumin. The unbound fraction of mercury in whey and plasma from mice was very small (<0.7%), and somewhat higher in plasma and whey from man. It is concluded, that the unbound fraction in plasma cannot be a determining factor for the observed differences in milk excretion between the two mercury compounds. Instead, it is suggested that methylmercury and to some extent inorganic mercury are transferred from plasma into milk using albumin as a passive carrier.

Adult↗

PubMed1999

Lactational exposure and neonatal kinetics of methylmercury and inorganic mercury in mice.

The concentration of mercury in milk and the distribution pattern in the sucking pup was followed over time after administration of a single iv injection of 0.5 mg/kg body wt of 203Hg-labeled methylmercuric chloride or mercuric chloride to lactating mice on Day 10 of lactation. Mercury concentrations in milk of the dams and in whole body, blood, plasma, GI-tract, liver, kidneys, and brain of the offspring were followed up to 11 days after dosing (until lactational Day 21). Following the inorganic mercury dose to the dams, most of the mercury in milk was delivered to the pups during the first 24 h, but the maximum mercury concentration in plasma and tissues of pups was not reached until 7 days after dosing, indicating a prolonged absorption of inorganic mercury in the sucking pup. Pups of dams given methylmercury were exposed to a much lower and constant mercury concentration in milk. The estimated accumulated mercury dose via milk per pup of dams given methylmercury was less than half of that estimated after the inorganic mercury dose. When the accumulated dose via milk from methylmercury-exposed dams was compared to the amount of mercury in pup's carcass (whole body minus GI-tract including content), it was revealed that almost all mercury delivered via milk was absorbed, and that the suckling pups had a very low elimination of mercury until lactational Day 17. Lactational exposure following a maternal methylmercury or inorganic mercury dose resulted in almost similar mercury concentrations in liver, kidneys, and plasma of the suckling, but higher concentrations in brain (as most 14 times) and also twice as high mercury body burden in the methylmercury group. Thus, differences in kinetics indicate that lactational exposure of methylmercury is a greater hazard for the breast-fed infant than inorganic mercury.

Animals↗

PubMed1999

Consistency of phonatory breathing patterns in professional operatic singers.

Breathing strategy is generally regarded as an important factor in operatic singing, because it is assumed to affect phonation. If so, professional singers should exhibit well-controlled, replicable breathing movements when repeating the same phrase. The purpose of the present study was to investigate to what extent professional opera singers show a consistent, exhalatory breathing behavior in a quasi-realistic concert situation. Respiratory movements were documented in 5 professional operatic singers, two women and three men, by means of respiratory inductive plethysmography. Comparison of respiratory data gathered from 3 renderings of the same phrases revealed high consistency with regard to lung volume (LV) behavior. The same applied to rib cage (RC) movements, suggesting a great relevance of RC control in singing. Consistency in abdominal wall (AW) movement was observed in 2 singers. These observations are in accordance with the idea that the breathing strategy plays an important role in voice production during singing. In addition, the correlation between LV changes, on the one hand, and RC and AW movements on the other, was examined. The contribution to LV changes from the RC and the AW varied across singers, thus suggesting that professional operatic singing does not request a uniform breathing strategy.

Abdominal Muscles↗

PubMed1999

Formant frequencies in country singers' speech and singing.

In previous investigations breathing kinematics, subglottal pressures, and voice source characteristics of a group of premier country singers have been analyzed. The present study complements the description of these singers' voice properties by examining the formant frequencies in five of these country singers' spoken and sung versions of the national anthem and of a song of their own choosing. The formant frequencies were measured for identical phonemes under both conditions. Comparisons revealed that the singers used the same or slightly higher formant frequencies when they were singing than when they were speaking. The differences may be related to the higher fundamental frequency in singing. These findings are in good agreement with previous observations regarding breathing, subglottal pressures, and voice source, but are in marked contrast to what has been found for classically trained singers.

Adult↗

PubMed1999

Voice source characteristics in six premier country singers.

Voice source characteristics as derived from inverse filtering were analyzed in 6 country singers' speech and singing. Results showed that the closed quotient varied systematically with vocal loudness, and that glottal compliance (the ratio between transglottal AC volume displacement and subglottal pressure) decreased with increases in fundamental frequency but remained unaffected by vocal loudness. No striking differences were found in source characteristics between speech and singing within subjects. The degree of phonatory press, as judged by a panel of 19 expert listeners, appeared related to the range in which the singer was singing and to the sound pressure level gain from a doubling of subglottal pressure.

Adult↗

PubMed1999

Identification of a novel SCD gene and expression of the SCD gene family in mouse skin.

We have refined the position of asebia locus by genotyping DNA from more than 600 backcross mice derived from asebia mouse and a genetically unrelated strain. One of the candidate genes in the locus is stearoyl-CoA desaturase (SCD). Previously two members of this gene family, namely SCD1 and SCD2, have been described. We have found, for the first time, that these SCD genes are expressed in skin. Moreover, we have identified a third species of SCD in the mouse skin. The most prominent SCD species is SCD1 in the mouse skin. The implications of this gene family to skin are discussed.

Animals↗

PubMed1999

Effects of subglottal pressure variation on professional baritone singers' voice sources.

Five professional operatic baritone singers' voice-source characteristics were analyzed by means of inverse filtering of the flow signal as captured by a flow mask. The subjects sang a long sustained diminuendo, from loudest to softest, three times on the vowels [a:] and [ae:] at fundamental frequencies representing 25%, 50%, and 75% of their total pitch range as measured in semitones. During the diminuendos, they repeatedly inserted the consonant [p] so that associated subglottal pressures could be estimated from the oral pressure during the p-occlusions. Pooling the three takes of each condition, ten subglottal pressures, equidistantly spaced between highest and lowest, were selected for analysis. Sound-pressure levels (SPL), peak-to-peak glottal airflow, maximum flow declination rate, closed quotient, glottal dc flow, and the level difference between the two lowest partials of the source spectrum (H1-H2) were determined. All parameters except the glottal dc flow showed a systematic variation with subglottal pressure or the fractional excess pressure over threshold. The results are given in terms of equations representing the average across subjects for the relation between subglottal pressure and each of the mentioned voice-source parameters.

Adult↗

PubMed1998

Kinetics of methylmercury and inorganic mercury in lactating and nonlactating mice.

The elimination of mercury was followed for 9 days (Days 10-19 of lactation) in milk and/or 21 days in blood and plasma of lactating and nonlactating mice administered a single iv injection of either 203Hg-labeled methylmercuric chloride or 203Hg-labeled mercuric chloride (0.5 mg Hg/kg body wt). Demethylation of methylmercury to inorganic mercury was taken into consideration by analyzing the data with a combined pharmacokinetic model based on the assumption of constant blood plasma ratios for methylmercury and inorganic mercury. A three-compartment model fitted the blood and plasma concentrations vs time profiles for both compounds. Plasma clearance and volume of distribution at steady state for methylmercury were 95. 3 ml/h/kg and 18,500 ml/kg, respectively, in lactating mice, and significantly higher than in nonlactating mice with values of 47.1 ml/h/kg and 9400 ml/kg, respectively. The terminal half-lives of methylmercury in plasma were similar, 170 h in lactating and 158 h in nonlactating mice. No differences were observed between the pharmacokinetic parameters in lactating and nonlactating mice administered inorganic mercury. The lactational transfer of mercury was more efficient following administration of inorganic mercury than after administration of methylmercury, with a five times higher peak concentration in milk, higher milk:plasma concentration ratios, and 8% of the administered dose excreted in milk compared with 4% for methylmercury. Mercury concentrations in milk following an iv dose of inorganic mercury decreased with a terminal half-life of 107 h, whereas after administration of methylmercury, the concentration of total mercury in milk remained at an almost constant level during the whole period of investigation. There was a nonlinear relationship between mercury in milk and plasma following inorganic mercury administration. It is suggested that inorganic mercury enters the mammary gland by a carrier-mediated transport system, which is saturated at high plasma levels of inorganic mercury. The present study shows that physiological changes during lactation alter the pharmacokinetics for methylmercury in mice but not for inorganic mercury.

Animals↗

PubMed1998

Effects of lung volume on vertical larynx position during phonation.

The vertical position of the larynx seems to be relevant to voice function. As a high vertical larynx position is often seen in hyperfunctional and strained voices, a lowering of a habitually elevated larynx is sometimes a specific goal in clinical voice therapy and different larynx-lowering exercises are used to achieve this goal. Earlier investigations have shown that pitch and to some extent also vocal loudness are relevant to vertical larynx position. In the present investigation, we examine if lung volume affects vertical larynx position. Using a multi-channel electroglottograph, the larynx position was measured in 29 healthy, vocally untrained subjects, who phonated at different lung volumes, pitches, and degrees of vocal loudness. The main results were that high lung volume was clearly associated with a lower larynx position as compared to low lung volume. In addition, vertical larynx position was strongly correlated with pitch. Both of these dependencies were shown to be stronger in males than in females. Our results suggest that lung volume is a factor that is highly relevant to larynx height in untrained subjects.

Adult↗

PubMed1998

Data on subglottal pressure and SPL at varied vocal loudness and pitch in 8- to 11-year-old children.

Phonation threshold pressure has been defined as the minimum subglottal pressure to generate phonation. Previous research has indicated that children may habitually employ higher subglottal pressures than adults. In the present investigation sound pressure level (SPL) and subglottal pressures at different pitch levels were measured at and above phonation threshold in nine children. Phonation threshold values were scattered in reasonable agreement with Titzes' prediction, although a discrepancy was noted regarding the frequency dependence in some voices. At normal conversational loudness and loudest level of phonation the children's Ps values were between two to four and four to eight times the predicted threshold values, respectively. At normal conversational loudness and habitual pitch subglottal pressures were lower than those previously observed for children, but similar to those found for female adults. The SPL in softest and loudest phonation were somewhat lower as compared to previous phonetogram data for children and for female adults. At normal loudness and habitual pitch the SPL values were similar to those of female adults. For a doubling of Ps mean SPL increased by 10.5 dB on the average.

Child↗

PubMed1998

Effects of lung volume on the glottal voice source.

According to experience in voice therapy and singing pedagogy, breathing habits can be used to modify phonation, although this relationship has never been experimentally demonstrated. In the present investigation we examine if lung volume affects phonation. Twenty-four untrained subjects phonated at different pitches and degrees of vocal loudness at different lung volumes. Mean subglottal pressure was measured and voice source characteristics were analyzed by inverse filtering. The main results were that with decreasing lung volume, the closed quotient increased, while subglottal pressure, peak-to-peak flow amplitude, and glottal leakage tended to decrease. In addition, some estimates of the amount of the glottal adduction force component were examined. Possible explanations of the findings are discussed.

Adult↗

PubMed1998

Risk assessment in relation to neonatal metal exposure.

Rapid changes in organ development and function occur during the neonatal period. During this period the central nervous system is in a rapid growth rate and highly vulnerable to toxic effects of, e.g., lead and methylmercury. Furthermore, the kinetics of many metals is age-specific, with a higher gastrointestinal absorption, less effective renal excretion as well as a less effective blood-brain barrier in newborns compared to adults. Due to their low body weight and high food consumption per kg of body weight, the tissue levels of contaminants can reach higher levels in newborns than in adults. Generally, there is a low transfer of toxic metals through milk when maternal exposure levels are low. However, knowledge is limited about the lactational transport of metals and the potential effects of metals in the mammary gland on milk secretion and composition. There are some data from rodents on the lactational transfer and the uptake in the neonate of inorganic mercury, methylmercury, lead and cadmium. Metal levels in human breast milk and blood samples from different exposure situations can give information on the correlation between blood and milk levels. If such a relationship exists, milk levels can be used as an indicator of both maternal and neonatal exposure. Better understanding of the neonatal exposure, including kinetics in the lactating mother and in the newborn, and effects of toxic metals in different age groups is needed for the risk assessment. Interactions with nutritional factors and the great beneficial value of breast-feeding should also be considered.

Adult↗

PubMed1997

Dependence of jaw opening on pitch and vowel in singers.

In singing, F0 sometimes is much higher than the typical frequency value of F1. According to previous investigations, sopranos raise F1 to a frequency near F0 by widening the jaw opening in such cases. In the present study, the jaw opening was measured in 10 professional singers of different categorizations whose task was to sing an ascending two-octave scale on different vowels. Their normal F1 values for these vowels were determined at a low F0. Only for the vowels /a/ and /a/ did the singers widen the jaw opening when F0 approached the F1 value measured at a low pitch. For the other vowels, jaw opening was widened, beginning at a higher F0. It is assumed that for these vowels the singers used other articulatory means to increase F1.

Female↗