Immigration policy, foreign agricultural labor, and exit intentions in the United States dairy industry.

United States agriculture is dependent on foreign labor. Current US immigration policies have been alleged to disrupt agricultural labor availability, particularly that of hired foreign labor. A national survey of dairy farmers across herd sizes and regions of the United States was conducted and the results were used to estimate the extent to which hired foreign labor dependency will affect exit intentions in dairy farming. This study found that the expected probability of exit from dairy farming increased as the use of hired foreign labor intensified. But the expected probability of exit also decreased rapidly as herd sizes got larger. Given the immigration policy currently in place, farmers expecting labor shortages in the future are expected to experience greater tendency to exit the industry.

Microwave-assisted extraction of active pharmaceutical ingredient from solid dosage forms.

The microwave assisted extraction (MAE) technique has been evaluated for the extraction of active pharmaceutical ingredients (API) from various solid dosage forms. Using immediate release tablets of Compound A as a model, optimization of the extraction method with regards to extraction solvent composition, extraction time and temperature was briefly discussed. Complete recovery of Compound A was achieved when samples were extracted using acetonitrile as the extraction solvent under microwave heating at a constant cell temperature of 50 degrees C for 5 min. The optimized MAE method was applied for content uniformity (single tablet extraction) and potency (multiple tablets extraction) assays of release and stability samples of two products of Compound A (5 and 25mg dose strength) stored at various conditions. To further demonstrate the applicability of MAE, the instrumental extraction conditions (50 degrees C for 5 min) were adopted for the extraction of montelukast sodium (Singulair) from various solid dosage forms using methanol-water (75:25, v/v) as the extraction solvent. The MAE procedure demonstrated an extraction efficiency of 97.4-101.9% label claim with the greatest RSD at 1.4%. The results compare favorably with 97.6-102.3% label claim with the greatest RSD at 2.9% obtained with validated mechanical extraction procedures. The system is affordable, user-friendly and simple to operate and troubleshoot. Rapid extraction process (7 min/run) along with high throughput capacity (up to 23 samples simultaneously) would lead to reduced cycle time and thus increased productivity.

Identification of inhibitor specificity determinants in a mammalian phosphodiesterase.

Mammalian phosphodiesterase types 3 and 4 (PDE3 and PDE4) hydrolyze cAMP and are essential for the regulation of this intracellular second messenger in many cell types. Whereas these enzymes share structural and biochemical similarities, each can be distinguished by its sensitivity to isozyme-specific inhibitors. By using a series of chimeric enzymes, we have localized the region of PDE4 that confers sensitivity to selective inhibitors. This inhibitor specificity domain lies within a short sequence at the carboxyl terminus of the catalytic domain of the protein, consistent with the competitive nature of inhibition by these compounds. Surprisingly, the identified region also includes some of the most highly conserved residues among PDE isoforms. A yeast-based expression system was used for the isolation and characterization of mutations within this area that confer resistance to the PDE4-specific inhibitor rolipram. Analysis of these mutants indicated that both conserved and unique residues are required for isoform-specific inhibitor sensitivity. In some cases, combined point mutations contribute synergistically to the reduction of sensitivity (suppression of IC50). We also report that several mutations display differential sensitivity changes with respect to distinct structural classes of inhibitors.

Increased mortality in children with mild vitamin A deficiency.

An average of 3481 preschool-age rural Indonesian children were re-examined every 3 months for 18 months. The mortality rate among children with mild xerophthalmia (night blindness and/or Bitot's spots) was on average 4 times the rate, and in some age groups 8 to 12 times the rate, among children without xerophthalmia. Mortality increased, almost linearly, with the severity of mild xerophthalmia (night blindness, Bitot's spots, and the two combined). These relations persisted after stratification for respiratory disease, wasting, gastroenteritis, pedal oedema, and childhood exanthems. Mild vitamin A deficiency was directly associated with at least 16% of all deaths in children aged from 1 to 6 years. These results suggest that mild xerophthalmia justifies vigorous community-wide intervention, as much to reduce childhood mortality as to prevent blindness, and that night blindness and Bitot's spots are as important as anthropometric indices in screening children to determine which of them need medical and nutritional attention.

Dietary practices and xerophthalmia among Indonesian children.

The stated frequency with which 30 Indonesian children with corneal xerophthalmia and age/sex/neighborhood matched controls ordinarily consumed vitamin- and provitamin A-rich foods was compared. Controls were more frequent consumers of eggs (p less than 0.05), fish (p less than 0.05), dark green leafy vegetables (p less than 0.05), carrots (p less than 0.01), and carotene-containing fruits (p less than 0.1). Similar data were collected on 358 children with Bitot's spots and on normal preschool age children in a countrywide survey. Breast-feeding was more common among normals than among cases (p less than 0.001). Normals were also more frequent consumers of mango and papaya during the 2nd and 3rd yr of life (p less than 0.05); and of dark green leafy vegetables and eggs during the 3rd through 6th yr of life (p less than 0.01). In two separate studies, differences in carotene consumption by normals and abnormals were confirmed by differences in their serum carotene levels. Approximately 80% of Indonesian families, with an without xerophthalmic children, consumed dark-green leafy vegetables at least once a day, and 99% at least once a week. Diet therefore appears to be an important factor in the genesis of xerophthalmia in Indonesia despite the availability of suitable provitamin A-rich foods.

Incidence, prevalence, and scale of blinding malnutrition.

4595 pre-school-age children in six villages of West Java were examined every 3 months. The incidence of active corneal xerophthalmia was 5 per 1000 per year (95% confidence limits, 2.6-7.5), and the average prevalence during each round of examinations was 12 per 10000. In a randomised, multistage cluster survey of 27084 rural children throughout Indonesia the population-weighted prevalence of active corneal disease among pre-school-age children was 6.4 per 10000 (95% confidence limits 3.2-9.6), 53% of that in the longitudinal study areas. At an adjusted incidence rate of 2.7 per 1000 per year, over 60000 Indonesian children become xerophthalmic every year. By extrapolation of these findings about 500000 new cases of xerophthalmia, half of which lead to blindness, occur each year in India, Bangladesh, the Philippines, and Indonesia combined.

History of nightblindness: a simple tool for xerophthalmia screening.

Among 5925 preschool-age children examined in a house to house rural field study, X1B (Bitot's spot with xerosis) and/or an history of nightblindness (XN) was presented in 325. Mean serum vitamin A levels among those with isolated XN (13.9 microgram/dl), isolated X1B (13.4 micrograms/dl), and coexistent XN/X1B (12.1 microgram/dl) were similar, and significantly below that of normal age/sex/neighborhood matched controls (17.6, 17.1, and 18.3 microgram/dl, respectively). The mean serum vitamin A level of the matched controls was significantly below that of normal, randomly sampled children from the study population as a whole (20.6 microgarm/dl). As independent screening criteria, disregarding the presence of absence of other signs, twice as many children had a history of XN as had X1B (84 and 41% of all clinically abnormal children, respectively). Of randomly sampled children 55% but only 15% of cases of XN had serum vitamin A levels above 20 microgram/dl. Of children with a history of nightblindness 97% had impaired scotopic vision on objective testing, but the mean serum vitamin A levels among test positives and negatives were identical. These results suggest a properly eleicited history of nightblindness can be almost as specific and far more sensitive an index of vitamin A deficiency and early xerophthalmia than the prescence of Bitot's spots (X1B), and that vitamin A deficiency is a clustered, neighborhood phenomenon rather than an isolated, sporadic occurrence.