A comparative analysis of primate nasal airways using magnetic resonance imaging and nasal casts

The nasal cavity is an intricate part of the respiratory tract. It is not only the site of olfaction, but also serves as a filter to protect the lower respiratory tract from inhaled pollutants. A substantial fraction of inhaled particles deposit in this region and may pose potential health risks. To predict possible sites of inhaled aerosol deposition and better understand health risks associated with inhaled aerosols in this region, it is necessary to examine the morphometry of the nasal passage. Magnetic resonance imaging (MRI) of the nose was done from the anterior to the posterior, in 3-mm sections, on five anesthetized rhesus monkeys and on two nasal casts (one human and one rhesus monkey). The MRI images were analyzed for perimeter and cross-sectional areas of each section. Results indicated that the left and right nasal passages were very symmetric for the five monkeys but not for the human cast. The cross-sectional area and, consequently, the volume varied greatly among monkeys in vivo. Measurements from the monkey cast exhibited 1.4-fold differences normalized body weight in cross-sectional areas, but with smaller differences in perimeter when compared to the MRI in vivo images. The human cast exhibited a volume three times greater than that of the monkey cast, while the surface area was approximately doubled. Results from this comparison showed many similarities in the structure of the monkey and human nose suggesting that the rhesus monkey would be a good human surrogate in aerosol deposition studies.

Measurements of airway dimensions and calculation of mass transfer characteristics of the human oral passage

This paper presents measurements of the geometric shape, perimeter, and cross-sectional area of the human oral passage (from oral entrance to midtrachea) and relates them through dimensionless parameters to the depositional mass transfer of ultrafine particles. Studies were performed in two identical replicate oral passage models, one of which was cut orthogonal to the airflow direction into 3 mm elements for measurement, the other used intact for experimental measurements of ultrafine aerosol deposition. Dimensional data were combined with deposition measurements in two sections of the oral passage (the horizontal oral cavity and the vertical laryngeal-tracheal airway) to calculate the dimensionless mass transfer Sherwood number (Sh). Mass transfer theory suggests that Sh should be expressible as a function of the Reynolds number (Re) and the Schmidt number (Sc). For inhalation and exhalation through the oral cavity (O-C), an empirical relationship was obtained for flow rates from 7.5-30.0 1 min-1: Sh = 15.3 Re0.812 Sc-0.986 An empirical relationship was likewise obtained for the laryngeal-tracheal (L-T) region over the same range of flow rates: Sh = 25.9 Re0.861 Sc-1.37 These relationships were compared to heat transfer in the human upper airways through the well-known analogy between heat and mass transfer. The Reynolds number dependence for both the O-C and L-T relationships was in good agreement with that for heat transfer. The mass transfer coefficients were compared to extrathoracic uptake of gases and vapors and showed similar flow rate dependence. For gases and vapors that conform to the zero concentration boundary condition, the empirical relationships are applicable when diffusion coefficients are taken into consideration.

An experimental method for measuring aerosol deposition efficiency in the human oral airway

An experimental technique was developed to measure the oral deposition of aerosols by successively drawing them passively through (1) the nasal and oral passage in series, and (2) the nose and an oral bypass "extension tube" inserted into the oral cavity just anterior to the uvula. To test this technique, a replicate human upper airway cast was challenged with monodisperse aerosols ranging in diameter from 3.6 to 150.0 nm at constant flow rates ranging from 7.5 to 30 L/min. For the inhalation study, test aerosols were drawn into the nasal cavity and directed either through the laryngeal-tracheal (L-T) section or the oral passage with/without the oral extension tube. The flow was reversed for the exhalation study. Deposition fractions of aerosols in the main oral cavity were found approximately equal to those in the L-T section for both inhalation and exhalation. Following this phase of the study, experimental measurements of total particle deposition fraction for the oral inlet-tracheal outlet path were performed. The results of these measurements agreed well with the calculated oral deposition fractions based on the initial measurements. This technique has application for measuring oral deposition of larger particles encountered in occupational environments.

Micronodulation: ultrasonographic sign of Hashimoto thyroiditis

The purpose of this work is to assess the validity of an ultrasonographic sign, micronodulation, in the diagnosis of Hashimoto thyroiditis. Among 101 patients found to have ultrasonographic features of micronodulation, 57 patients had autoantibody test results available. Fifty-four patients were positive and three were negative for the autoantibodies. Therefore, the positive predictive value for micronodulation in diagnosing Hashimoto thyroitis is 94.7%. The micronodules were 0.1 to 0.65 cm in size, hypoechoic, and surrounded by an echogenic rim. This corresponds to accentuated lobulation on the pathologic specimen. Although micronodulation is highly diagnostic of Hashimoto thyroiditis, the ultrasonographic features of eight biopsy-proved masses caused by Hashimoto thyroiditis varied and were not specific for the disease.

A follow-up study of childhood nasopharyngeal radium irradiation in Washington County, Maryland

In 1978 an epidemiologic study exploring the health consequences of nasopharyngeal radium irradiation among individuals treated for adenoid enlargement in Washington County, Maryland, found an excess risk of brain tumors and a deficit of female breast cancers. The study population included all persons first seen at the Washington County Clinic for the Prevention of Deafness in Children from 1940 to January 1, 1960. We will continue the follow-up of irradiated and nonirradiated patients to (1) assess the risk of brain tumors and other neoplasms of the head and neck developing during a 40-year period, (2) assess hormone-related disorders resulting from irradiation of the pituitary gland, and (3) compare cancer incidence and mortality rates among exposed and nonexposed groups. Of the 2135 persons eligible for this study, 93.5% have been traced, and 90% have replied to a mailed questionnaire that elicits information on demographic characteristics, reproductive and medical history, infertility, and other sources of radiation exposure. Information on cancer incidence and mortality is being obtained from the Washington County Cancer Registry and death certificate files from Washington County and the Social Security Administration. Statistical methods to be used in the data analysis include standardized mortality ratios, standardized cancer incidence ratios, and Kaplan-Meier survival analysis.

Paraumbilical venous collateral circulations: color Doppler ultrasound features

Using Color Doppler ultrasonography to trace the dilated paraumbilical vein to its connection with systemic veins in 27 patients, we have found four major pathways: In type 1 (63%), the vein connected with the external iliac vein via the inferior epigastric vein. In type 2 (3.7%), the vein connected with the saphenous vein via the superficial epigastric vein. In type 3 (22.2%), the vein connected with the internal thoracic vein via the superior epigastric vein. Type 4 (11.1%) is a combination of types 1 and 2. A frank caput medusa was not seen, but occult caput medusa were seen in two patients. Turbulent flow was seen at the junction between inferior epigastric and external iliac veins, paraumbilical and superficial epigastric veins, and superficial epigastric and saphenous veins in some patients. Color Doppler ultrasonography is a convenient, noninvasive method for determining the course and associated hemodynamic changes in the paraumbilical collateral circulation.

Conformational change and inactivation of membrane phospholipid-related activity of cardiotoxin V from Taiwan cobra venom at acidic pH

The phospholipid binding activity of cardiotoxin V from Naja naja atra (CTX A5) was studied by use of Langmuir monolayers and found to exhibit pH-dependence in binding to phosphatidylcholine membrane with an apparent pKa around 6.0. Proton NMR investigation of the CTX A5 molecule in the presence of phosphatidylcholine micelles reveals a decrease in association of CTX A5 with membranes at low pH as a result of the protonation of His-4 near the membrane binding site of loop I region of CTX. The pH-dependent binding can be attributed mainly, but not solely, to the change in charge content of the CTX molecule upon His-4 protonation at the membrane/water interface. This is shown by analyzing the pH- and ionic strength dependence of binding of CTXs to phospholipid monolayers according to Gouy-Chapman theory. The protonation of the His-4 residue also results in a local conformational change in the loop I region since the chemical shifts of amide protons for the amino acid residues from Cys-3 to Thr-14 are all found to vary as a function of pH with an apparent pKa similar to that of His-4. Interestingly, the effect is relayed to other amino acid residues in the structural core of the protein such as those in C-terminal (Lys-60, Cys-61, and Asn-62) and triple-stranded antiparallel beta-sheet (Cys-22, Lys-24, Ala-25, Arg-38, and Ala-41) regions. An additional local conformational change in the molecule results around pH 5 as evidenced by circular dichroism spectroscopic studies, although this change does not affect the characteristic beta-sheet and three-finger loop structure of CTX molecule as revealed by two-dimensional NOESY 1H NMR study. The latter conformational change at acidic pH, however, completely inactivates CTX-induced aggregation/fusion activity of sphingomyelin vesicles. The results suggest that deciphering the functional sites of CTXs on the basis of structure and dynamics determined at low pH should be done with caution. Since 19 out of 44 CTX homologues with known amino acid sequence contain His-4, the effect of His-4 on the structure and function of CTX molecules is important and is discussed in terms of the diverse membrane targets of CTX subtypes. Also discussed is the pH-induced activation of snake venom proteins in the victim.

Transjugular intrahepatic portosystemic shunt: correlation of portal vein velocity measurements and portosystemic pressure gradients

To assess the relationship between portal vein velocity measurements and portosystemic gradients, color Doppler sonography was performed on 12 patients before and after transjugular intrahepatic portosystemic shunt placement. An additional patient was examined before and after shunt modification. The average maximum portal vein velocity increased from 15.7 cm s-1 before shunt placement to 43.5 cm s-1 after shunt placement, while the average portosystemic gradient decreased from 22.0 mm Hg before shunt placement to 7.9 mm Hg after shunt placement. Flow was observed within the shunt in 11 of the 12 cases. Shunt velocity was measurable in nine patients, with an average value of 115.7 cm s-1. Reversal of intrahepatic portal vein flow was observed in 10 cases following shunt placement. Color Doppler sonography is a useful non-invasive tool in the evaluation of intrahepatic portosystemic shunts, and changes in portal vein velocity correlate well with changes in the portosystemic gradient.

Junctional parenchyma: revised definition of hypertrophic column of Bertin

The so-called hypertrophic column of Bertin is a normal variation and simply represents unresorbed polar parenchyma of one or both of the two subkidneys that fuse to form a normal kidney. It contains renal cortex, pyramids, and columns (septa) of Bertin. (Since all elements of the tissue are normal, that is, neither hypertrophic nor a displaced or embryonic rest, it is referred to as "junctional parenchyma.") When a masslike lesion is suspected at sonography or excretory urography, diagnosis of junctional parenchyma can be made with a high degree of certainty when sonography shows that the structure (a) is located between the overlapping portion of two renal sinus systems, (b) is bordered by a junctional parenchymal line and defect, (c) contains renal cortex, pyramids, and columns of Bertin, and (d) contains renal cortex that is continuous with the adjacent renal cortex of the same subkidney.

Use of an acoustic transponder for US visualization of biopsy needles

A 20-gauge Chiba needle with a stylet embedded with polyvinyldifluoride (PVDF), a polymer that acts as an acoustic-electric transducer, facilitated a variety of diagnostic and therapeutic ultrasound (US)-guided interventions in nine patients. PVDF receives acoustic energy from the US scanner and transmits an electrical signal through the stylet and a shielded cable to the scanner, which results in appearance of a bright echo on the monitor at the location of the needle tip.

Anatomic variations and abnormalities in the diaphragm seen with US

The authors report their experience with diaphragmatic structures that simulate intrahepatic masses at abdominal ultrasonography (US). In a series of 74 patients, diaphragmatic slips were the most common finding (34 patients). The slips could be differentiated from masses by scanning along their long axis to demonstrate elongated structures with multiple linear echoes. Scalloping of the diaphragm, associated with multiple slips, was seen in 10 patients. Partial eventration was found in 23. Inversion of a hemidiaphragm, caused by a large pleural effusion or intrathoracic mass, was seen in 13 patients. Pleural masses affecting the diaphragm were seen in 13 patients; focal hypertrophy of a diaphragmatic crus simulated a mass in three. Real-time US allowed the differentiation of diaphragmatic abnormalities from lesions.

Deposition of ultrafine aerosols in rat nasal molds

To evaluate the health effects of air pollutants on the respiratory tract, it is critical to determine the regional deposition of inhaled aerosols. Information on deposition of larger particles (greater than 0.2 microns) in the nasal passages of laboratory animals is available; the deposition fraction increases with increasing particle size. However, little deposition information is available for ultrafine particles of less than 0.2 microns. Three clear, plastic molds (models) of the nasal passages of F344/N rats, prepared from metal replica casts were used in these studies. Total deposition of ultrafine aerosols in the casts was determined by using a unidirectional flow system. The pressure drops measured in the casts were a function of flow rate to the power of 1.4-1.6, indicating that flow through the nasal passages has nonlaminar components. Deposition data were obtained by using monodisperse sodium chloride aerosols with particle sizes ranging from 0.2 to 0.005 microns, at inspiratory and expiratory flow rates of 200 to 600 ml/min. Similar deposition data were obtained for two of the casts studied. Deposition efficiency was greatest for the smallest particles, and decreased with increasing particle size and flow rate. At an inspiratory flow rate of 400 ml/min, which is comparable to the mean respiratory flow of an adult male F344 rat with a respiratory minute volume of 200 ml, deposition efficiencies reached 40 and 70% for 0.01- and 0.005-microns particles, respectively. These studies demonstrated that turbulent diffusional deposition was the dominant mechanism for uptake of ultrafine particles by the nasal passages.

Sonographic evaluation of portal hypertension in children

Portal hypertension, an expected consequence of cirrhosis, often has an insidious course in children. A noninvasive technique using abdominal sonography has been previously employed by several investigators as a means of diagnosing this condition. Their technique involves sonographically measuring the diameter of the lesser omentum, which increases as a result of engorged collaterals. In this communication, the method is successfully employed in two children, an infant in whom cirrhosis developed who eventually died from acquired immunodeficiency syndrome, and one whose portal hypertension was relieved after orthotopic liver transplantation. Although successful in these two instances, the theoretical basis on which this technique is based is critically evaluated. Anatomical relationships are reviewed that would caution sonographers who attempt to duplicate these studies. Modifications of the technique that will minimize potential false positive results are also discussed.

Deposition of cigarette smoke particles in the rat

The fractional deposition of cigarette smoke particles in the respiratory tracts of rats was studied. Male and female rats were conditioned in nose-only exposure tubes 25 min/day for 2 days, exposed to cigarette smoke at mass concentrations of 95 or 341 mg/m3, 25 min/day for 3 days, and then exposed to smoke at mass concentrations of 212 and 657 mg/m3, 25 min/day for 5 days. Mainstream cigarette smoke was generated by a modified Walton smoking machine from two 1R3 research cigarettes burned sequentially for each exposure. Deposition studies were conducted by placing the rats in plethysmograph tubes to allow respiratory minute volume measurements during exposure, then exposing them to [14C]dotriacontane-labeled cigarette smoke at mass concentrations of 202 or 624 mg/m3 for 25 min, using the same smoking machine. Size distribution, real-time concentration, and 14C activity of the smoke particles were determined using a multijet Mercer impactor, a real-time aerosol monitor, and filter samples, respectively. Immediately after the exposure, the rats were terminated to determine the distribution of the 14C. Individual lung lobes, trachea and lobar bronchi, head, larynx, kidneys, liver, gastrointestinal (GI) tract, blood, and depleted carcass of each rat were analyzed for 14C content. Results showed that the GI tract contained 16-31% of the total activity, indicating significant clearance from the large airways and nose to the GI tract during the exposure and during the 10-15 min between the cessation of the exposure and the removal of the organs. Total deposition of the inhaled 14C activity was 20.1 +/- 1.6% for both exposure concentrations. The intrapulmonary deposition fractions (lung lobes plus airways below the lobar bronchi) were 12.4 +/- 0.9 and 15.9 +/- 1.4% for concentrations of 202 and 624 mg/m3, respectively, suggesting a slight enhancement in upper airway deposition for animals exposed to the higher smoke concentration.

Lung retention and binding of [14C]-1-nitropyrene when inhaled by F344 rats as a pure aerosol or adsorbed to carbon black particles

1-Nitropyrene (NP), as found in the environment, is more typically associated with carbonaceous particles than found as an aerosol of the pure compound. To determine whether (and why) an association with particles resulted in prolonged lung retention of NP, rats were exposed to 14C-NP as a pure aerosol or adsorbed on carbon black particles. Total 14C retained in the lung was greater at all times from 0.5 h to 30 d after exposure to 14C-NP adsorbed to carbon black particles than after exposure to pure 14C-NP (p less than .05). The fraction of total 14C in lung bound to carbon black particles decreased steadily with time after exposure, indicating in vivo removal of NP from the particles. At 0.5 h after exposure, the fraction of the estimated deposited 14C that was covalently bound to lung macromolecules was twofold greater for NP adsorbed on carbon black than for pure NP. Covalently bound 14C in lungs increased with time after exposure to 14C-NP adsorbed to carbon black, reaching levels of approximately 1% of the deposited radioactivity at 7-30 d after exposure, whereas levels of covalently bound 14C declined with time after exposure to pure NP. Thus, at 30 d after exposure, the amount of 14C covalently bound to lung macromolecules was approximately 10-fold greater (p less than .05) in rats that inhaled 14C-NP adsorbed on carbon black particles than in rats that inhaled pure 14C-NP aerosols. These results suggest that association of NP with carbon black particles augments the interaction of reactive metabolites of NP with target macromolecules. This phenomenon is thought to be related to the slow release of NP from carbon black particles, and may augment the biological effects of inhaled NP when adsorbed on carbon black or similar particles in the environment.

Adrenal gland and nonrenal retroperitoneum

Ultrasound, as the initial cross-sectional imaging technique, confirmed the value of axial records. Although computerized tomography and possibly magnetic resonance offers better resolution, ultrasonography has the advantage of being less expensive, convenient, and highly portable. With these specific indications and reservations, ultrasonography of the adrenal and retroperitoneum has an accepted role in imaging.

The prevalence of hyperandrogenism in 109 consecutive female patients with diffuse alopecia

Endocrine dysfunction was studied in 109 consecutive female patients with moderate to severe alopecia, mostly of a diffuse pattern. The study included an evaluation of associated hirsutism and/or menstrual dysfunction, plasma hormonal measurements, and ultrasonography of the ovaries. A control group of 24 ovulatory, nonhirsute, nonalopecia individuals was also studied. Of the 109 patients, 70 (64.2%) had no clinical evidence of hirsutism or menstrual dysfunction. Two of 44 patients tested with cosyntropin (Cortrosyn) had 21-hydroxylase deficiency, whereas two other patients had hyperprolactinemia caused by pituitary tumors. Hyperandrogenism was defined as an increase in any of the plasma androgens (testosterone, non-sex hormone-binding globulin bound testosterone, dehydroepiandrosterone sulfate, androstenedione, or dihydrotestosterone) and was noted in 42 of the 109 patients studied (38.5%). Of these 42 patients, 11 were ovulatory with no evidence of clinical hirsutism, 13 were ovulatory and hirsute, and 18 had oligomenorrhea or amenorrhea with or without hirsutism with confirmatory evidence of polycystic ovarian disease. Patients with diffuse alopecia may demonstrate hyperandrogenism, even in the absence of hirsutism, oligomenorrhea, or amenorrhea. The most common endocrine disorder in this series of patients with diffuse alopecia was polycystic ovarian disease.