Pre-COVID-19 Social Determinants of Health Among Mexican Migrants in Los Angeles and New York City and Their Increased Vulnerability to Unfavorable Health Outcomes During the COVID-19 Pandemic

Journal of Immigrant and Minority Health - COVID-19 has disproportionally affected underrepresented minorities (URM) and low-income immigrants in the United States. The aim of the study is to...     

Multiband compression limiting for hearing-impaired listeners

Four multiband compression limiters and two linear amplification systems were compared in terms of the intelligibility of consonant-vowel-consonant (CVC) nonsense syllables for two hearing-impaired listeners over a 30 dB range of input levels. Each system incorporated one of two frequency-gain characteristics and one of three limiting characteristics (no limiting, moderate limiting, or severe limiting). The subjects were instructed to choose overall listening levels that would permit speech spanning the range of input levels to be as intelligible as possible and comfortable for long-term listening. Relative to linear amplification, the overall gain selected by the subjects increased by roughly 5 and 11 dB for the moderate and severe limiter, respectively. With linear amplification, the maximum score, 82 percent correct, was obtained at the highest input level and scores fell roughly 34 percentage points as input level was reduced. With compression limiting, although the maximum scores, 81 percent and 79 percent correct, were obtained at lower input levels, performance was comparable to that with linear amplification. Also, scores spanned a range of only 22 and 9 percentage points across the range of input levels with the moderate and severe limiter, respectively. This benefit was due to the improved scores provided by compression limiting at the low input levels. However, this advantage was offset somewhat by the disadvantage provided by compression at high input levels relative to linear amplification. Error analysis indicated that the spectral degradations introduced by independent compression of 16 frequency bands may have caused the reduced intelligibility at higher input levels.     

Predicting the solubility of sulfamethoxypyridazine in individual solvents. I: Calculating partial solubility parameters

Sulfamethoxypyridazine, a representative model of a drug molecule, is used to test the extended Hansen method for estimating partial solubility parameters of solid compounds. Solubilities are determined in polar and nonpolar solvents. The method provides reasonable partial parameters for the sulfonamide, and it may be useful in obtaining partial parameters for other drug molecules. A four-parameter extended Hansen approach involving proton donor and acceptor parameters is used in fitting the data to a theoretical model. A term, Wh, is introduced as an empirical measure of solute-solvent interactions due to hydrogen bonding. The use of the empirical term Wh allows the researcher to fit experimental solubilities and thus design regression models and equations which provide a reasonable prediction of solubilities of a polar drug in a number of very different solvents. A Flory-Huggins size correction term improves the prediction of sulfamethoxypyridazine solubilities in these irregular solutions.     

Shoulder instability: impact of glenohumeral arthrotomography on treatment

We used arthrotomography to study the glenoid labrum in 114 patients. Sixty-nine of the patients had anatomic instability of the shoulder (including recurrent dislocation and subluxation of the shoulder), and 45 patients had functional instability of the shoulder (denoted by chronic pain, clicking of the joint, and the sensation that an unstable condition exists without the objective signs of it). Labral tears were revealed arthrotomographically in 86% of the patients with anatomic instability, while only 40% of the patients with functional instability had labral abnormalities, and these were primarily of minor severity. Fifty-six patients (44 of whom had anatomic instability; 12, functional instability) required surgery. The surgical findings were correlated with the arthrotomographic findings, and no false-positive results were revealed. However, arthrotomography demonstrated only part of the pathologic condition of two patients. These results confirm that there is a strong correlation between labral pathologic conditions and anatomic instability of the shoulder. Arthrotomographic studies have a great impact on the selection of therapy in cases of both anatomic and functional instability of the shoulder.     

Removal of the endothelial layer in perfused mesenteric vascular bed of the rat.

The endothelial layer was removed from the isolated mesenteric vascular bed of the rat by perfusion with hypotonic Tyrode solution for 12.5 min. This procedure damaged more than 95% of the endothelial cells. After endothelial removal, the response to norepinephrine was significantly enhanced, whereas the relaxation induced by acetylcholine (ACh) was completely abolished. The results of this work show that perfusion with hypotonic solutions provides a reliable method of endothelial removal in isolated perfused vascular beds, allowing the study of endothelial-dependent vascular responses.     

Partial-solubility Parameters of Naproxen and Sodium Diclofenac

The expanded Hansen method was tested for determination of the solubility parameters of two non-steroidal anti-inflammatory drugs, naproxen and sodium diclofenac. This work describes for the first time the application of the method to the sodium salt of a drug. The original dependent variable of the expanded Hansen method, involving the activity coefficient of the drug, was compared with the direct use of the logarithm of the mole fraction solubility lnX₂ in the solubility models. The solubility of both drugs was measured in pure solvents of several chemical classes and the activity coefficient was obtained from the molar heat and the temperature of fusion. Differential scanning calorimetry was performed on the original powder and on the solid phase after equilibration with the pure solvents, enabling detection of possible changes of the thermal properties of the solid phase that might change the value of the activity coefficient. The molar heat and temperature of fusion of sodium diclofenac could not be determined because this drug decomposed near the fusion temperature. The best results for both drugs were obtained with the dependent variable lnX₂ in association with the four-parameter model which includes the acidic and basic partial-solubility parameters δ_a and δ_b instead of the Hansen hydrogen bonding parameter δ_h. Because the dispersion parameter does not vary greatly from one drug to another, the variation of solubility among solvents is largely a result of the dipolar and hydrogen-bonding parameters, a fact that is being consistently found for other drugs of small molecular weight. These results support earlier findings with citric acid and paracetamol that the expanded Hansen approach is suitable for determining partial-solubility parameters. The modification introduced in the expanded Hansen method, i.e. the use of lnX₂ as the dependent variable, provides better results than the activity coefficient used in the original method. This is advantageous for drugs such as sodium diclofenac for which the ideal solubility cannot be estimated. This paper shows for the first time that the method is suitable for determination of the partial-solubility parameters of a sodium salt of a drug, sodium diclofenac.     

Linkage of the MHC to familial multiple sclerosis suggests genetic heterogeneity. The Multiple Sclerosis Genetics Group

Multiple sclerosis (MS) is a demyelinating autoimmune disease of the central nervous system. While its etiology is not well understood, genetic factors are clearly involved. Until recently, most genetic studies in MS have been association studies using the case-control design testing specific candidate genes and studying only sporadic cases. The only consistently replicated finding has been an association with the HLA-DR2 allele within the major histocompatibility complex (MHC) on chromosome 6. Using the genetic linkage design, however, evidence for and against linkage of the MHC to MS has been found, fostering suggestions that sporadic and familial MS have different etiologies. Most recently, two of four genomic screens demonstrated linkage to the MHC, although specific allelic associations were not tested. Here, a dataset of 98 multiplex families was studied to test for an association to the HLA-DR2 allele in familial MS and to determine if genetic linkage to the MHC was due solely to such an association. Three highly polymorphic markers (HLA-DR, D6S273 and TNFbeta) in the MHC demonstrated strong genetic linkage (parametric lod scores of 4.60, 2.20 and 1.24, respectively) and a specific association with the HLA-DR2 allele was confirmed (TDT; P < 0.001). Stratifying the results by HLA-DR2 status showed that the linkage results were limited to families segregating HLA-DR2 alleles. These results demonstrate that genetic linkage to the MHC can be explained by the HLA-DR2 allelic association. They also indicate that sporadic and familial MS share a common genetic susceptibility. In addition, preliminary calculations suggest that the MHC explains between 17 and 62% of the genetic etiology of MS. This heterogeneity is also supported by the minority of families showing no linkage or association with loci within the MHC.      

A malformed child with a recombinant chromosome 7, rec(7) dup p, derived from a maternal pericentric inversion inv(7)(p15q36).

We report a child with facial dysmorphic features, hypoplasia of the external genitalia, intestinal malrotation, congenital cardiac defect, and minor limb anomalies. Chromosome studies showed a recombinant chromosome 7, rec(7) dup p, resulting from a maternal pericentric inversion inv(7)(p15 q36). Thus, this child had partial trisomy 7p in addition to a small distal monosomy 7. The clinical findings are compared with those found in previous reports of trisomy 7p. Finally, some general principles for genetic counselling are discussed.