Transcriptomic and Single-Cell Analysis of the Murine Parotid Gland

The salivary complex of mammals consists of 3 major pairs of glands: the parotid, submandibular, and sublingual glands. While the 3 glands share similar functional properties, such as saliva secretion, their differences are largely based on the types of secretions they produce. While recent studies have begun to shed light on the underlying molecular differences among the glands, few have examined the global transcriptional repertoire over various stages of gland maturation. To better elucidate the molecular nature of the parotid gland, we have performed RNA sequencing to generate comprehensive and global gene expression profiles of this gland at different stages of maturation. Our transcriptomic characterization and hierarchical clustering analysis with adult organ RNA sequencing data sets has identified a number of molecular players and pathways that are relevant for parotid gland biology. Moreover, our detailed analysis has revealed a unique parotid gland-specific gene signature that may represent important players that could impart parotid gland-specific biological properties. To complement our transcriptomic studies, we have performed single-cell RNA sequencing to map the transcriptomes of parotid epithelial cells. Interrogation of the single-cell transcriptomes revealed the degree of molecular and cellular heterogeneity of the various epithelial cell types within the parotid gland. Moreover, we uncovered a mixed-lineage population of cells that may reflect molecular priming of differentiation potentials. Overall our comprehensive studies provide a powerful tool for the discovery of novel molecular players important in parotid gland biology.

Ofloxacin in human serum, urine, and tear film after topical application

We evaluated the systemic absorption of ofloxacin eyedrops in humans and their availability in the tear film. Serum, urine, and tear film concentrations of ofloxacin were measured in 30 healthy women topically treated with 0.3% ofloxacin, in both eyes, four times daily for 10 1/2 days. Serum was collected before the first daily dose on days 1 and 11 and at 18 time points before the second dose. Maximum serum ofloxacin concentrations (1.89 +/- 1.13 ng/ml) after 10 1/2 days of topical dosing were more than 1,000 times lower than those reported after standard oral doses of 300 mg ofloxacin. Urine was collected for the 24-h period after the first daily dose on days 1 and 10. Topical ofloxacin was excreted in the urine primarily in unmodified form and recovery rates were significantly higher on day 10 (76.1 +/- 41.5%) than on day 1 (56.6 +/- 31.6%) (p less than 0.05). Both serum and urine data give evidence to accumulations of ofloxacin over a 10 1/2-day period. The low serum concentration at steady state suggests an extremely low potential for producing systemic effects. No systemic side effects attributable to topical ofloxacin were observed. Mild ocular irritation was reported by two patients while under treatment. Tears were collected 4 h after the first treatment on day 11 and at 5, 10, 20, 30, and 40 min after the second treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Food effects on the nighttime pharmacokinetics of Theo-Dur tablets

A randomized crossover study demonstrated major food effects on the pharmacokinetics of Theo-Dur, two 200-mg theophylline anhydrous sustained-release tablets, as an evening dose. These effects included a higher maximum serum theophylline level and relatively prolonged delay in drug absorption, both significant. The findings, which showed marked individual variation, could be clinically important for patients receiving evening medication.

Comparison of quality of life on nitrendipine and propranolol

A multicenter, randomized, double-blind, comparative study was conducted in 274 patients with mild to moderate hypertension to assess the impact of nitrendipine and propranolol on quality of life. After placebo baseline, 136 patients were given nitrendipine (5-20 mg b.i.d.) and 138 were given propranolol (40-120 mg b.i.d.). Quality of life was evaluated at baseline, weeks 6-10, and weeks 14-18 of the maintenance period. At weeks 6-10, the nitrendipine group became significantly more vigorous (p less than 0.01) and less fatigued (p less than 0.05) than the propranolol group. Propranolol subjects noted decreased problems of trembling hands (p less than 0.01) and alcohol use (p less than 0.05) than the nitrendipine subjects. No other significant differences between groups in mood states, troublesome conditions (insomnia, headaches, and loss of appetite), or sexual satisfaction were noted at this visit, and patient willingness to continue study medication was marginally significantly higher (p less than 0.1) in the nitrendipine group than in the propranolol group. At weeks 14-18, the propranolol subjects perceived significantly decreased problems with the "felt worried, tense, and drank alcohol to cope" factor (p less than 0.05); however, there were no differences between groups at this visit for Profile of Mood States (POMS) scores, sex life variables, or medication preference. Based on within-group analysis, the propranolol group perceived a reduction in partner sexual satisfaction (p less than 0.05). Overall, nitrendipine seemed to be better tolerated than propranolol.

Long-term antihypertensive effects and safety of nitrendipine in patients with mild, moderate, and severe hypertension

A study of 31 patients with mild or moderate hypertension and 17 patients with severe hypertension was conducted to evaluate the long-term safety and efficacy of nitrendipine, a new calcium channel blocker with a long duration of action. Nitrendipine (5-40 mg bid) was given as monotherapy or in combination with hydrochlorothiazide and/or propranolol. Seventeen patients (54%) with mild to moderate hypertension were controlled with nitrendipine alone, but all except one patient with severe hypertension required combination therapy. In patients with mild or moderate hypertension, nitrendipine reduced supine blood pressure from a baseline mean 154/100 mm Hg to 136/87 mm Hg after 1 year of treatment (P less than .05). In patients with severe hypertension, supine blood pressure was reduced from 186/124 mm Hg to 148/91 mm Hg by the end of the planned treatment period (P less than .05; mean duration, 10 weeks). During extended observation, antihypertensive effect was sustained for up to 2.5 years and 1.6 years in patients with mild or moderate and severe hypertension, respectively. Nitrendipine was well tolerated; and only one patient, a moderate hypertensive, discontinued treatment because of pedal edema. The results of this long-term study show that nitrendipine alone or in combination with a diuretic and/or a beta blocker is a safe and effective agent for the treatment of patients with all degrees of hypertension.

Effects of antacids and food on absorption of famotidine

The effect of a high potency antacid and food on the bioavailability of famotidine was studied in 17 healthy volunteers in an open randomized three-way cross-over trial. After an overnight fast, famotidine was administered to each subject as follows: 40 mg famotidine orally alone; 40 mg orally with antacid; and 40 mg orally with a standard breakfast. Coadministration of the antacid caused a small but significant reduction in the maximum plasma concentration (Cmax) of famotidine from 81.1 +/- 54.2 to 60.8 +/- 21.6 ng ml-1 (P less than 0.05) and a small decrease in the area under plasma concentration-time curve [AUC] from 443.3 +/- 249.2 to 355.0 +/- 125.1 ng ml-1 h (P greater than 0.05). However, there was only a minimal effect of food on these parameters; the Cmax and [AUC] were 81.6 +/- 29.6 ng ml-1 and 434.8 +/- 145.9 ng ml-1 h, respectively.

Three-year caries increments after fluoride rinses or topical applications with a fluoride varnish

251 9-12-yr-old children completed a 3-yr, double-blind, clinical trial of two caries preventive fluoride programs. Caries increments and progression patterns were compared in two groups of children who rinsed every fortnight with a 0.2% NaF solution or received biannual topical applications with a fluoride varnish (Fluor-Protector). Clinically recorded mean DFS increments were 3.3 +/- 0.2 (SE) in the rinse group and 3.5 +/- 0.2 in the varnish group. In both groups nearly half of these increments were recorded in the occlusal surfaces of second molars. The mean incremental DFS recorded radiographically on approximal surfaces of posterior teeth were 1.1 +/- 0.2 and 1.5 +/- 0.2 in the rinse and varnish group, respectively. None of the inter-group differences were statistically significant (P greater than 0.05). Detailed analyses of the radiographic scores revealed a similar and extremely slow caries progression in the two study groups and they strengthened the conclusion of equal clinical efficacy of the two treatments. None of the fluoride programs had been able to change preestablished patterns of caries development among the children.

Choline magnesium trisalicylate: comparative pharmacokinetic study of once-daily and twice-daily dosages

This randomized crossover study compared the pharmacokinetics of choline magnesium trisalicylate tablets administered once daily (3000 mg of salicylate) or twice daily (1500 mg of salicylate) for six d. Serum salicylate levels were measured by HPLC. Mean "trough" concentrations fell within the therapeutic range (5-30 mg/dL) with either regimen and were relatively constant, indicating that the steady state had been reached. The 24-h area under the salicylate curve (AUC0-24 h) after the final 3000-mg salicylate dose averaged about twice the mean 12-h AUC after the last 1500-mg dose, indicating that the two dosing regimens were equally bioavailable. Clinical observations and results of laboratory safety studies indicate that both dosage schedules of the drug are well tolerated. The present findings support the once-daily therapeutic use of choline magnesium trisalicylate.

Carcinogenic N-nitrosodimethylamine as a contamination in drugs containing 4-dimethylamino-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one (amidopyrine, aminophenazone)

A total of 68 commercially available drugs containing amidopyrine were investigated for contamination with the strong carcinogen N-nitrosodimethylamine (NDMA). All samples contained varying amounts of NDMA. About half of the drugs contained 1--10 micrograms/kg, 40% contained 11--50 micrograms/kg, 7% contained 51--10 micrograms/kg and one sample had 370 micrograms/kg. NDMA-contents in batches of pure amidopyrine that had been utilized for preparation of drugs were higher than those in the respective drugs: about one-third was in the range of 20--50 micrograms/kg, one-third had 51--100 micrograms/kg, and one-third was above 100 micrograms/kg. There was, however, no correlation between NDMA-contents of batches of the pure substance and NDMA-contents of the drugs prepared from these batched. NDMA concentrations in the samples were inhomogenously distributed. It could be demonstrated that amidopyrine in substance reacts extremely rapidly with nitrogen oxides from the air to form NDMA. Ascorbic acid, which prevents nitrosamine formation in aqueous-acidic solution, under these conditions had no protective effect.

Occurrence of volatile N-nitrosamines in animal diets

46 samples of commercially available diets for experimental animals have been analysed for their content of volatile N-nitrosamines by use of a nitrosamine-specific detection method (TEA-detector). 80% of all analysed samples were positive for N-nitrosodimethylamine with a maximum content of 79 ppb (microgram/kg) found in one sample. 59% of the samples were positive for N-nitrosopyrrolidine with 26 ppb as highest content. In 3 samples trace quantities (less than 1 ppb) of N-nitrosodiethylamine were found, one sample contained N-nitrosopiperidine (4 ppb).