Fast pollen tube growth in Conospermum species

BACKGROUND AND AIMS

An unusual form of pollen tube growth was observed for several Conospermum species (family Proteaceae). The rate of pollen tube growth, the number of tubes to emerge and the ultrastructure of these tubes are given here.

METHODS

Pollen was germinated in vitro in different sucrose concentrations and in the presence of calcium channel blockers, and tube emergence and growth were recorded on a VCR. Measurements were taken of the number of tubes to emerge and rate of tube emergence. Pollen behaviour in vivo was also observed. The ultrastructure of germinated and ungerminated pollen was observed using TEM.

RESULTS

After 10 s to 3 min in germination medium, up to three pollen tubes emerged and grew at rates of up to 55 micro m s(-1); the rate then slowed to around 2 micro m s(-1), 30 s after the initial growth spurt. Tubes were observed to grow in pulses, and the pulsed growth continued in the presence of calcium channel blockers. Optimal sugar concentration for pollen germination was 300 g L(-1), in which up to 81 % of pollen grains showed fast germination. Germination and emergence of multiple tubes were observed in sucrose concentrations of 100-800 g L(-1). The vegetative and generative nuclei moved into one of the tubes. Multiple tubes from a single grain were observed on the stigma. Under light microscopy, the cytoplasm in the tube showed a clear region at the tip. The ultrastructure of C. amoenum pollen showed a bilayered exine, with the intine being very thick at the pores, and elsewhere having large intrusions into the plasma membrane. The cytoplasm was dense with vesicles packed with inner tube cell wall material. Golgi apparatus producing secretory vesicles, and mitochondria were found throughout the tube. The tube wall was bilayered; both layers being fibrous and loosely packed.

CONCLUSIONS

It is proposed that, for Conospermum, initial pollen tube wall constituents are manufactured and stored prior to pollen germination, and that tube extension occurs as described in the literature for other species, but at an exceptionally fast rate.

Mannitol in cardioplegia as an oxygen free radical scavenger measured by malondialdehyde

Oxygen free radicals (OFRs) are associated with ischaemia-reperfusion injury involving many organs, including the heart, which can lead to depressed cardiac function and abnormalities in the cardiac ultrastructure. This is seen upon the release of the aortic crossclamp when the ischaemic myocardium is reperfused in patients undergoing cardiopulmonary bypass (CPB). Various studies have shown that by adding OFR scavenging agents or antioxidants to the CPB prime or cardioplegia, cardiac performance improves. Mannitol is an osmotic diuretic with free radical scavenging properties, which has been shown to reduce the extent of ischaemic injury and improve the function of the myocardium. This study evaluated how effective mannitol is as an OFR scavenger by administering different concentrations of cardioplegia antegrade into the aortic root, thus maximising its effects directly upon the myocardium rather than being diluted in the CPB prime. Thirty-three patients undergoing primary coronary artery bypass grafting (CABG) were, by double blind random selection, allocated into one of three groups: group 1, a control group (consisting of 11 patients) receiving no mannitol; group 2 (11 patients), receiving a concentration of 4 g/l; and group 3 (11 patients), receiving 8 g/l. Three blood samples were taken directly from the coronary sinus during bypass: the first sample at the start of bypass, just prior to the crossclamp being applied; the second sample just after removal of the crossclamp; and the third sample just prior to termination of bypass. All samples were then centrifuged and the plasma analysed for malondialdehyde (MDA) using high-performance liquid chromatography (HPLC). MDA, an endproduct of lipid peroxidation, causes cellular damage and disruption of cell membranes when tissue antioxidants are exhausted. The more MDA produced, the greater the depletion of tissue antioxidants secondary to OR formation during reperfusion when the aortic crossclamp is removed. HPLC is a useful biochemical study; however, it is not a direct indicator of depressed myocardial function, such as an invasive test would be, and this should be borne in mind. Statistically, the results do not show a significant difference among the three groups or among the three samples. However, a trend can be seen, which shows lower levels of MDA in the two groups receiving mannitol and there is an indication of a rise in MDA levels upon the start of reperfusion in the two groups receiving mannitol, but not the control group. It is concluded that further samples would be needed to find a significant difference in MDA concentrations.

The University of California, Irvine experience with tomotherapy using the Peacock system

Our institutional experience using the Peacock system for intensity-modulated radiation therapy (IMRT) is summarized. Over 100 patients were treated using this system, which is fitted to a Clinac 600C linac. Both cranial and extracranial lesions have been treated using this modality. Immobilization is achieved either with the Talon system for cranial sites or an Aquaplast cast. Target volumes up to 500 cm3 have been treated. Multiple lesions (up to 3) were treated in one setup. The range of dose/fractionation schemes used was 15 Gy/1 fx (radiosurgical treatment) - 80 Gy/40 fx. Dose validation studies were carried out using film and ion chamber dosimetry in a specially designed phantom. Optimal dose distributions were attainable using inverse treatment planning for IMRT delivery. These were found to encompass the target volumes accurately using dose validation phantom studies. Immobilization methods used were accurate to within 1 mm, as evidenced by daily portal films. IMRT using the Peacock system offers the advantage of delivery of conformal therapy to high doses safely and accurately. This provides the opportunity for dose escalation studies, retreatment of previously treated tumors, as well as treating multiple targets in one setup. The system may be fitted to a conventional linac without major modifications.

cAMP enhances Cx43 gap junction formation and function and reverses choline deficiency apoptosis

Previously, it had been shown that acute choline deficiency (CD) induced apoptosis in cultured rat liver epithelial cells, whereas cells that are adapted to survive in low-choline-containing medium acquire resistance to CD apoptosis and undergo malignant transformation. Thus, understanding the mechanisms of action of CD could increase our understanding of the role of choline, an essential nutrient, in the process of malignant transformation. The present experiments were designed to test the hypothesis that CD might function as a pro-apoptotic trigger by altering the localization of connexin 43 gap junction protein and gap junctional intercellular communication (GJIC). Established liver epithelial cells (WB cells; Hep3B cells) were maintained in a defined, serum-free medium control (70 microM choline) or choline deficient medium (CD, 5 microM choline) and the localization of connexin 43 protein (Cx43) was studied by immunocytochemistry and Western blotting. In nontumorigenic WB cells, CD apoptosis was associated with retention of Cx43 in the golgi/ER region of the cytoplasm and decreased GJIC as measured using a preloading fluorescent dye transfer method (calcein AM/DiIC(18)). Cells maintained in CD in the presence of 8-bromoadenosine 3':5'-cyclic monophosphate exhibited restoration of Cx43 at the plasma membrane and increased GJIC and inhibition of apoptosis. These studies show that CD apoptosis in nontumorigenic liver epithelial cells is associated with alterations to Cx43 and GJIC and that an uncoupling of Cx43 localization and GJIC is related to resistance to CD apoptosis in transformed liver epithelial cells.

Tetra-O-methyl nordihydroguaiaretic acid induces G2 arrest in mammalian cells and exhibits tumoricidal activity in vivo

The transcription inhibitor tetra-O-methyl nordihydroguaiaretic acid (M4N) was found to arrest the proliferation of C3, C33a, CEM-T4, and TC-1 cells in culture at the G2 stage of the cell cycle. Investigation into the mechanism of arrest revealed that M4N reduces mRNA levels and subsequent protein production of the cyclin-dependent kinase CDC2, resulting in the inactivation of the CDC2/cyclin B complex (maturation promoting factor). When injected intratumorally in a C3-cell induced C57bl/6 mouse tumor model system, M4N demonstrated substantial tumoricidal activity that correlated with a reduction in tumor cell CDC2 protein levels. These findings suggest that M4N may be a useful chemotherapeutic agent for the control of unregulated cellular proliferation.

Obesity hypertension: role of leptin and sympathetic nervous system

Obesity may account for as much as 65% to 75% of human essential hypertension in most industrialized countries. Excess renal sodium reabsorption and a hypertensive shift of renal-pressure natriuresis play a key role in mediating obesity hypertension. Sympathetic activation contributes to obesity-induced sodium retention and hypertension because adrenergic blockade or renal denervation markedly attenuates these changes. Recent observations suggest that leptin and its multiple interactions with other neurochemical pathways in the hypothalamus may be a partial link between excess weight gain and increased sympathetic activity. Short-term administration of leptin into the cerebral ventricles increases renal sympathetic activity, and long-term intravenous leptin infusions in nonobese rodents at rates that raise plasma concentrations to the levels found in severe obesity increase arterial pressure and heart rate through adrenergic activation. Also, transgenic mice that overexpress leptin develop hypertension. Acute studies suggest that the renal sympathetic effects of leptin may depend on interactions with other neurochemical pathways in the hypothalamus, including melanocortin-4 receptors. However, it is unclear whether this pathway or others, such as neuropeptide Y, mediate the long-term effects of leptin on blood pressure. In addition, leptin has other actions, such as stimulation of nitric oxide formation and enhancement of insulin sensitivity, which may tend to reduce blood pressure in some conditions. Although the precise role of these complex interactions in human obesity has not been elucidated, this is an important area for further investigation, especially considering the current epidemic of obesity in most industrialized countries.

Catalytic cleavage of the androgen-regulated TMPRSS2 protease results in its secretion by prostate and prostate cancer epithelia

We identified TMPRSS2 as a gene that is down-regulated in androgen-independent prostate cancer xenograft tissue derived from a bone metastasis. Using specific monoclonal antibodies, we show that the TMPRSS2-encoded serine protease is expressed as a Mr 70,000 full-length form and a cleaved Mr 32,000 protease domain. Mutation of Ser-441 in the catalytic triad shows that the proteolytic cleavage is dependent on catalytic activity, suggesting that it occurs as a result of autocleavage. Mutational analysis reveals the cleavage site to be at Arg-255. A consequence of autocatalytic cleavage is the secretion of the protease domain into the media by TMPRSS2-expressing prostate cancer cells and into the sera of prostate tumor-bearing mice. Immunohistochemical analysis of clinical specimens demonstrates the highest expression of TMPRSS2 at the apical side of prostate and prostate cancer secretory epithelia and within the lumen of the glands. Similar luminal staining was detected in colon cancer samples. Expression was also seen in colon and pancreas, with little to no expression detected in seven additional normal tissues. These data demonstrate that TMPRSS2 is a secreted protease that is highly expressed in prostate and prostate cancer, making it a potential target for cancer therapy and diagnosis.

Brain proton magnetic resonance spectroscopy and imaging in children exposed to cocaine in utero

OBJECTIVE

The effects of prenatal cocaine exposure have been examined using neurobehavioral and brain structural evaluations; however, no study has examined the effects of prenatal cocaine on brain metabolism. Proton magnetic resonance spectroscopy ((1)H-MRS) is a noninvasive method to examine the biochemistry of various brain regions. The purpose of this study was to examine the possible neurotoxic effects of prenatal cocaine exposure on the developing brain using (1)H-MRS.

METHODS

Cocaine-exposed children (n = 14) and age-matched unexposed control participants (n = 12) were evaluated with MRI and localized (1)H-MRS. Metabolite concentrations of N-acetyl-containing compounds (NA), total creatine (Cr), choline-containing compounds, myoinositol, and glutamate + glutamine were measured in the frontal white matter and striatum.

RESULTS

Despite an absence of structural abnormalities in either group, children exposed to cocaine in utero had significantly higher Cr (+13%) in the frontal white matter. NA, primarily a measure of N-acetyl aspartate and neuronal content, was normal in both regions examined by (1)H-MRS. Normal NA suggests no significant neuronal loss or damage in the 2 brain regions examined in children exposed to cocaine prenatally.

CONCLUSIONS

Consistent with findings in abstinent adult cocaine users, we found increased Cr in the frontal white matter, with normal NA in children exposed to cocaine. These findings suggest the need to investigate further possible abnormalities of energy metabolism in the brain of children exposed to cocaine in utero. In addition, this study demonstrates the feasibility of using (1)H-MRS to investigate the effects of prenatal drug exposure on the developing brain.

Association of serum estrogen level and ischemic neuroprotection in female rats

Estrogen-related ischemic neuroprotection has been documented in male and ovariectomized female rats. The precise molecular mechanism underlying estrogen's neuroprotective effect remains obscure. In the present study, we examined whether endogenous estrogen levels affect post-ischemic outcomes in normal cycling female rats. Occlusion of both the common carotid arteries and the right middle cerebral artery (1.5 h) followed by reperfusion (24 h) caused cortical infarction, increased neutrophil accumulation, and elevated antioxidant enzyme and lactate dehydrogenase activities. These post-ischemic changes varied in the female rats and were inversely correlated with circulating estrogen levels. More severe post-ischemic changes and injury accompanied the decline in circulating estrogen levels in normal cycling female rats, indicating that estrogen is probably the major hormonal player in female resistance to ischemia.

Role of sympathetic nervous system and neuropeptides in obesity hypertension

Obesity is the most common cause of human essential hypertension in most industrialized countries. Although the precise mechanisms of obesity hypertension are not fully understood, considerable evidence suggests that excess renal sodium reabsorption and a hypertensive shift of pressure natriuresis play a major role. Sympathetic activation appears to mediate at least part of the obesity-induced sodium retention and hypertension since adrenergic blockade or renal denervation markedly attenuates these changes. Recent observations suggest that leptin and its multiple interactions with neuropeptides in the hypothalamus may link excess weight gain with increased sympathetic activity. Leptin is produced mainly in adipocytes and is believed to regulate energy balance by acting on the hypothalamus to reduce food intake and to increase energy expenditure via sympathetic activation. Short-term administration of leptin into the cerebral ventricles increases renal sympathetic activity, and long-term leptin infusion at rates that mimic plasma concentrations found in obesity raises arterial pressure and heart rate via adrenergic activation in non-obese rodents. Transgenic mice overexpressing leptin also develop hypertension. Acute studies suggest that the renal sympathetic effects of leptin may depend on interactions with other neurochemical pathways in the hypothalamus, including the melanocortin-4 receptor (MC4-R). However, the role of this pathway in mediating the long-term effects of leptin on blood pressure is unclear. Also, it is uncertain whether there is resistance to the chronic renal sympathetic and blood pressure effects of leptin in obese subjects. In addition, leptin also has other cardiovascular and renal actions, such as stimulation of nitric oxide formation and improvement of insulin sensitivity, which may tend to reduce blood pressure in some conditions. Although the role of these mechanisms in human obesity has not been elucidated, this remains a fruitful area for further investigation, especially in view of the current "epidemic" of obesity in most industrialized countries.

Longitudinal evaluation of activated protein C resistance among normal pregnancies of Hispanic women

OBJECTIVE

This study was undertaken to describe pregnancy-associated activated protein C resistance and the presence of the factor V Leiden mutation in a sample population of pregnant Hispanic women.

STUDY DESIGN

Twenty healthy Hispanic women with single intrauterine pregnancies were randomly selected. Blood samples were taken before 8 weeks' gestation, every 4 weeks during pregnancy, and at 6 weeks post partum. Samples were collected, separated, and stored at -70 degrees C until assay. Standard and modified partial thromboplastin time-based assays were used to evaluate response to activated protein C. A sensitivity ratio < or =2 indicated resistance to activated protein C. Repeated measures analysis of variance and unpaired t tests were used as appropriate. P <.05 was considered significant.

RESULTS

Mean (+/-SEM) maternal age was 29 +/- 5 years, and most women were multiparous. Mean gestational age at delivery was 38 weeks' gestation, and the mean birth weight was 3000 g. According to the standard assay, 10 women (50%) acquired activated protein C resistance by 13 weeks' gestation, and this condition persisted through delivery and resolved post partum. Another two had preexisting activated protein C resistance. Results of the standard assay were significantly different for women with preexisting and pregnancy-associated activated protein C resistance (1.55 vs 2.18; P =.01). The modified assay distinguished between women with preexisting and pregnancy-associated activated protein C resistance at 8 weeks' gestation, 24 weeks' gestation, and post partum. The pregnancies of the women with preexisting activated protein C resistance were complicated by oligohydramnios at 34 weeks' gestation and required delivery at 36 weeks' gestation. One infant was small for gestational age. Allele-specific polymerase chain reaction analysis demonstrated that both patients with preexisting activated protein C resistance carried one copy of the factor V Leiden mutation.

CONCLUSION

The incidences of pregnancy-associated and factor V Leiden mutation-associated activated protein C resistances in our cohort of gravid Hispanic women was higher than previously reported. Factor V Leiden-associated activated protein C resistance in two patients was associated with adverse perinatal outcome.

Detection of plant genes using a rapid, nonorganic DNA purification method

We have developed a simple procedure for the preparation of plant genomic DNA using FTA paper. Plant leaves were crushed against FTA paper, and the genomic DNA was purified using simple, nonorganic reagents. The 18S rRNA gene and the gene encoding the ribulose-1, 5-bisphosphate carboxylase/oxygenase large subunit (rbcL) from the chloroplast genome were detected by PCR amplification of DNA on FTA paper. DNA amplification was successful using extracts from 16 dicot and monocot plants. Studies of specific plant extracts revealed that extracts of leaf samples could be collected and stored at room temperature on FTA paper without a decrease in the DNA amplification success rate for more than a month. Both the 18S RNA gene and the rbcL gene were detected in the genomic DNA isolated from various soybean cultivars stored in this manner. Furthermore, by modestly increasing the number of cycles of DNA amplification, we were able to detect the uidA gene in transgenic tobacco and rice leaves as well as a single copy gene linked to the resistance gene of cyst nematode race 3 using genomic DNA isolated on FTA paper. These results demonstrate that genomic DNA isolated using FTA paper can be used for the detection of plant genes, from a wide range of plants with either high or low gene copy number and of either nuclear or cytoplasmic origin.

STEAP: a prostate-specific cell-surface antigen highly expressed in human prostate tumors

In search of novel genes expressed in metastatic prostate cancer, we subtracted cDNA isolated from benign prostatic hypertrophic tissue from cDNA isolated from a prostate cancer xenograft model that mimics advanced disease. One novel gene that is highly expressed in advanced prostate cancer encodes a 339-amino acid protein with six potential membrane-spanning regions flanked by hydrophilic amino- and carboxyl-terminal domains. This structure suggests a potential function as a channel or transporter protein. This gene, named STEAP for six-transmembrane epithelial antigen of the prostate, is expressed predominantly in human prostate tissue and is up-regulated in multiple cancer cell lines, including prostate, bladder, colon, ovarian, and Ewing sarcoma. Immunohistochemical analysis of clinical specimens demonstrates significant STEAP expression at the cell-cell junctions of the secretory epithelium of prostate and prostate cancer cells. Little to no staining was detected at the plasma membranes of normal, nonprostate human tissues, except for bladder tissue, which expressed low levels of STEAP at the cell membrane. Protein analysis located STEAP at the cell surface of prostate-cancer cell lines. Our results support STEAP as a cell-surface tumor-antigen target for prostate cancer therapy and diagnostic imaging.

A new cardiothoracic centre: 'how to do it?'

All cardiac surgical patients, emergency and routine, from the South West peninsula of England had to travel long distances until 19 months ago, a stressful if not dangerous situation. This paper describes the planning, commissioning and start-up of a brand new cardiac surgical facility. The lessons learnt may help similar projects as provision of specialist health care decentralizes.

Lipase-catalyzed dynamic resolution of naproxen 2,2,2-trifluoroethyl thioester by hydrolysis in isooctane

A lipase-catalyzed enantioselective hydrolysis process under continuous in situ racemization of substrate by using trioctylamine as an organic base was developed for the production of (S)-naproxen from racemic naproxen thioesters in isooctane. Naproxen 2,2, 2-trifluoroethyl thioester and 45 degrees C were selected as the best substrate and temperature, respectively, by comparing the time-course variations for the racemization of (S)-naproxen thioesters containing an electron-withdrawing group. A detailed investigation of the effect of trioctylamine concentration on the kinetic behaviors of the thioester in racemization and enzymatic reaction was conducted, in which more than 70% conversion of the racemate (or 67.2% yield of (S)-naproxen) with eep value higher than 92% was obtained. Copyright 1999 John Wiley & Sons, Inc.

A comparison of two dosing regimens of intravaginal misoprostol for second-trimester pregnancy termination

OBJECTIVE

To compare the effectiveness of misoprostol administered intravaginally every 6 versus every 12 hours for termination of second-trimester pregnancies.

METHODS

One hundred pregnant women at 12-22 weeks' gestation were randomized to receive 200 microg of misoprostol intravaginally either every 6 or every 12 hours for up to 48 hours.

RESULTS

The incidences of abortion within 48 hours after initial drug administration were 87.2 and 89.2%, the complete abortion rates 43.9 and 33.3%, and the mean abortion intervals 13.8 and 14.0 hours in the 6- and 12-hour groups, respectively. Side effects were similar between groups.

CONCLUSION

Misoprostol administered vaginally is effective for terminating second-trimester pregnancies. Shortening the dosing interval from 12 to 6 hours produced no significant benefit.

Motion of a Colloidal Sphere Covered by a Layer of Adsorbed Polymers Normal to a Plane Surface

A combined analytical-numerical study is presented for the slow motion of a spherical particle coated with a layer of adsorbed polymers perpendicular to an infinite plane, which can be either a solid wall or a free surface. The Reynolds number is assumed to be vanishingly small, and the thickness of the surface polymer layer is assumed to be much smaller than the particle radius and the spacing between the particle and the plane boundary. A method of matched asymptotic expansions in a small parameter lambda incorporated with a boundary collocation technique is used to solve the creeping flow equations inside and outside the adsorbed polymer layer, where lambda is the ratio of the characteristic thickness of the polymer layer to the particle radius. The results for the hydrodynamic force exerted on the particle in a resistance problem and for the particle velocity in a mobility problem are expressed in terms of the effective hydrodynamic thickness (L) of the polymer layer, which is accurate to O(lambda2). The O(lambda) term for L normalized by its value in the absence of the plane boundary is found to be independent of the polymer segment distribution and the volume fraction of the segments. The O(lambda2) term for L, however, is a sensitive function of the polymer segment distribution and the volume fraction of the segments. In general, the boundary effects on the motion of a polymer-coated particle can be quite significant. Copyright 1999 Academic Press.

Chemiluminescent detection of AFLP markers

Nonradioactive amplified fragment-length polymorphism (AFLP) marker detection, a PCR-based, DNA-fingerprinting technique, was achieved by blotting AFLP products after electrophoresis onto a nylon membrane and subsequently hybridizing the blot with an alkaline phosphatase-labeled AFLP probe. Similar AFLP profiles were obtained by both a nonradioactive, chemiluminescent detection technique and by conventional AFLP marker detection using 32P-labeled AFLP primers. The suitability of the method using different gel systems combined with subsequent chemiluminescent detection of AFLP markers is validated by similar dendrograms that were generated using the unweighted pair group method with arithmetic averages (UPGMA). Moreover, chemiluminescent detection of AFLP markers using a universal AFLP nonradioactive probe has been successfully applied on prokaryotes such as Agrobacterium and eukaryotic genomes such as soybean and fungi.

Health status of Asian Americans: United States, 1992-94

OBJECTIVES

This report compares the health status of selected Asian national origin groups.

METHODS

1992-94 National Health Interview Survey (NHIS) data were analyzed for six Asian national origin groups (Chinese, Filipino, Asian Indian, Japanese, Vietnamese, and Korean), the Asian and Pacific Islander (API) population as a whole, and the non-Hispanic white population. Unadjusted and age-adjusted estimates and standard errors of health indicators and sociodemographic characteristics were generated. A broad range of health issues was studied including respondent-assessed health status, activity limitation, physician contacts, restricted activity days, hospital episodes, smoking status, and knowledge of acquired immunodeficiency syndrome (AIDS).

RESULTS

A greater age-adjusted percent of Vietnamese (17.2 percent) and Korean (12.8 percent) persons had fair or poor respondent-assessed health status than persons of Chinese, Filipino, and Japanese descent (6.1-7.4 percent). A lower age-adjusted percent of Chinese persons (6.5 percent) experienced activity limitation compared with Filipino, Japanese, and Vietnamese persons (9.4-13.2 percent). Japanese persons (4.9 contacts) had a greater average annual number of physician contacts than Chinese persons (3.1 contacts) after age adjusting the data. When the data were age adjusted, a higher percent of Korean adults (22.5 percent) were current smokers than Chinese (10.0 percent) and Asian Indian adults (8.7 percent). A higher age-adjusted percent of Vietnamese (21.2 percent) and Asian Indian (18.0 percent) adults reported knowing nothing about AIDS compared with Japanese adults (5.1 percent). A greater proportion of Vietnamese adults (91.6 percent) had not been tested for the AIDS virus infection compared with Chinese, Filipino, Asian Indian, and Japanese adults (72.6-78.5 percent) after age adjusting the data.

CONCLUSIONS

Differences in health emerge when data on the API population are analyzed by national origin group. Estimates of health presented for the API population as a whole mask differences among subgroups.

Assessment of vocal function using simultaneous aerodynamic and calibrated videostroboscopic measures

Despite many attempts to model how vocal fold movements relate to the aerodynamic forces acting on them during phonation, there have been few simultaneous measurements of glottal area and transglottal air pressures and flows. A novel system is described that combines endoscopic measurement of glottal area with aerodynamic flow and pressure measures made during phonation. Results from bench top model tests and from one human subject are presented. For both tests, an aerodynamic model of airflow through a constriction was used to predict the area of the constriction (glottis), and these predictions were compared with endoscopic measurements. The results showed good correlation between predicted and observed areas; however, for small constrictions (<0.025 cm2), whether artificial or glottal, the errors in estimating areas with either optical or aerodynamic methods increase significantly. These results suggest that this measurement system has the potential to enhance the assessment of vocal function.