Corneal and scleral penetration studies of 6-hydroxyethoxy-2-benzothiazole sulfonamide: a topical carbonic anhydrase inhibitor

A newly synthesized topical carbonic anhydrase inhibitor, 6-hydroxyethoxy-2-benzothiazole sulfonamide (6-HS), was used as a model drug to determine its corneal and scleral permeabilities in rabbit eyes. The corneal permeability coefficient of 6-HS for short duration glaucoma and normal rabbit eye was not significantly different (its mean value was around 2.9 x 10(-6) cm/sec), while the corneal permeability coefficient for long duration glaucoma rabbit eye was 1.8 times greater than that for the normal eye. The sclera was found to have a higher permeability than the cornea in that after four hours perfusion the amount of drug which passed through the sclera was 11 times greater than that of the cornea. In addition, it was also noted that after topical instillation of 50 microL of 3% 6-HS gel the aqueous humor concentrations of 6-HS in short duration glaucoma eye and normal eye were not statistically different.

Aneurysm of the internal carotid artery simulating pituitary tumor with panhypopituitarism--a case report

A 59-year-old female patient presented with conscious disturbance and hyponatremia. Baseline endocrine studies revealed secondary hypothyroidism and hypoadrenalism. Further studies of skull X-ray, brain CT scan, dynamic endocrine tests and visual field examination favored pituitary tumor with panhypopitutarism. Trans-sphenoid surgical intervention was arranged. However the management was changed because the preoperative carotid angiography revealed the mass lesion over the cavernous sinus region was an aneurysm, not a pituitary tumor. The patient refused surgical intervention for the aneurysm and received thyroxine and cortisone replacement until the present time. Because the surgical treatment of an aneurysm is different from a pituitary tumor, we reported this case to emphasize the importance of routine carotid angiography in the evaluation of the sellar mass.

C-peptide response to glucagon in young diabetics

Pancreatic beta cell function was measured in 15 nondiabetic controls, 10 insulin-dependent diabetics (IDD) and 19 non-insulin-dependent diabetics (NIDD), aged 18 to 45 years, by means of the peripheral serum C-peptide response to 1 mg of glucagon. The fasting serum C-peptide (FCP) in IDD was lower than in the controls and NIDD (p less than 0.01), but there was no significant difference between the controls and NIDD (p greater than 0.05). The maximal in crement of serum C-peptide (delta CP) after glucagon stimulation in the controls was higher than in IDD and NIDD (p less than 0.01), and there was a gap between IDD (less than or equal to 0.69 ng/ml) and NIDD (1.20 ng/ml). During the glucagon test, serum C-peptide concentrations were highest in the first 15 minutes unlike plasma glucose which reached its highest value between 20 and 40 minutes. NIDD, either obese or nonobese, had a lower mean delta CP value than did controls. In the controls, IDD and NIDD, the FCP was correlated well with delta CP (r = 0.61, 0.93 and 0.59) but not with fasting plasma glucose (r = 0.19, -0.08 and 0.23). During the glucagon test, the mean maximal increments of plasma glucose were between 52.5 and 62.5 mg/dl. Nausea was the main complaint in 19 (43%) of the subjects but it was mild and transient. In conclusion, measuring serum C-peptide response after glucagon stimulation is a simple and safe test which may be a discriminative method to establish insulin dependency in young diabetic patients.

Vector coupled-mode analysis of coupling between two identical optical fiber cores

The vector coupled-mode analysis considering the exact HE(11) modes is applied to two single-mode coupled optical fiber cores, including the strongly guiding fibers. The accuracy of the conventional coupled-mode theory and the recently formulated new theory as applied to the two-core system is examined. Array modes of different polarization states are considered. It is shown that the full-wave coupled-mode calculations behave well in predicting the array-mode propagation constants beyond the weakly guiding regime and that the simpler conventional theory can provide satisfactory results when applied in the vectorial form.

HLA-A,B,C and DR antigens in Chinese with non-insulin-dependent diabetes: comparison with goitrous diabetics

To examine the relationship between HLA antigens and Type 2 non-insulin-dependent diabetes (NIDDM), 72 patients were studied and compared with 282 controls. Twenty of 72 patients had an associated non-toxic goiter. The clinical features of the goitrous diabetic patients were similar to those without goiter except that those with goiter were predominantly female (95%). Of the 46 antigens assayed, only A10 was increased in the 72 diabetics when compared with the controls (12.5 vs 5.7%, RR = 2.37, chi 2 = 4.07, p less than 0.05), but statistically this was not significant after p value correction. In the patients with goiter, antigens A2, A9, A10, B27, BW46, CW1, DR1, DR5, DR8, DRW9 showed 2 folds or greater differences in frequencies when compared to the non-goitrous diabetics. However, only A2 had a significant decrease in the former as compared with the latter (30.0 vs 59.6%, chi 2 = 5.07, p less than 0.05), but this was also statistically insignificant. The present study showed no significant HLA associations in Chinese NIDDM patients with or without non-toxic goiter, and the distribution of each antigen was not related to the presence or absence of goiter.

Interaction of rabbit lipoproteins and red blood cells with liposomes of egg yolk phospholipids

After intravenous injection of liposomes prepared from egg yolk phospholipids into rabbits, the phospholipids were readily assimilated by the lipoproteins, and there were increases in the circulating levels of cholesterol and phospholipids. The increases in cholesterol level were mainly due to increases of free cholesterol. Gradient ultracentrifugation showed that the lipoproteins decreased in density, and gel filtration chromatography showed that they increased in particle size. Upon electrophoresis, they exhibited slower mobility. Liposomes recovered from rabbits 3 hr after the injection contained free cholesterol, apolipoproteins A-I, E and traces of C. The apolipoprotein may target the liposomes for uptake by hepatocytes. Incubation of the liposomes with rabbit red blood cell membranes in vitro caused a decrease in cholesterol content of the membranes. However, the cholesterol/phosphate ratio in red blood cells isolated from the rabbits after the injection of liposomes did not change significantly, suggesting rapid replenishment of red blood cell cholesterol in vivo, possibly by equilibration with lipoprotein cholesterol or tissue cholesterol. These results suggest that the injection of phospholipid liposomes may have an antiatherogenic effect by the removal of tissue cholesterol and enhancing hepatic disposal of cholesterol through the reverse cholesterol transport mechanism.

Hydrolysis kinetics of diacetyl nadolol

Diacetyl nadolol, a prodrug of nadolol and a beta-blocker, has corneal permeability approximately 20 times higher than that of its parent compound due to its higher lipophilicity. Hydrolysis studies were conducted for diacetyl nadolol at various elevated temperatures and pH values to provide stability information for its ophthalmic preparations. The apparent rate constants for diacetyl nadolol hydrolysis to acetyl nadolols and nadolol were determined. Within the neutral pH range (6.8 to 8.2), the hydrolysis of diacetyl nadolol may be proposed as specific base catalysis. Various constants for diacetyl nadolol hydrolysis to acetyl nadolols and acetyl nadolols to nadolol were respectively listed as following: activation energy, 9.78 and 11.39 kcal/mol; entropy at 25 degrees C, -9.78 and -5.86 cal/mol.deg; second-order rate constant at 75 degrees C, 3.47 X 10(4) and 2.22 X 10(4) M-1h-1. According to these kinetic constants, a diacetyl nadolol aqueous solution with pH 6.5 may be prepared as an antiglaucoma agent. The shelf-life was estimated to be only 43 d at room temperature (25 degrees C). However, when the storage temperature is lowered to 5 degrees C, the shelf-life can be extended to greater than 2 years.

The effect of blood storage on lymphocyte subpopulations

Duplicate heparinized blood samples were drawn from 22 subjects; 2 healthy subjects, 1 vitiligo and 19 with thyroid or parathyroid diseases. All 22 portion of specimens was immediately processed and examined for T cell subsets by indirect immunofluorescence, using monoclonal antibodies as control. 10 another portion of specimens were stored at 4 degrees C for 24 hours before testing. 12 another portion of specimens were pretreated with Ficoll-Hypaque separation before storage. When the whole blood was stored at 4 degrees C overnight and compared with samples tested with fresh cells, there was a significant decrease in OKT3+ cells (total T cells) (p less than 0.05) and a slight decrease in OKT4+ cells (T helper/inducer cells) and in OKT4/OKT8 ratio. However, these abnormalities were reversed when the lymphocytes were separated before storage. There was a significant decrease of natural killer cells (p less than 0.05) when specimens were pre-treated with Ficoll-Hypaque before storage. The reactivity of Ia+ cells was altered after overnight storage (p greater than 0.05).

Effect of vitamin A deficiency upon gonadotropin response to gonadotropin-releasing hormone

There is a monotypic change in basal serum gonadotropin levels following retinol treatment of chronically vitamin A-deficient (VAD) male rats. The present study was undertaken to investigate the hypothesis that the specific increase in serum follicle-stimulating hormone (FSH) represents a change in gonadotrope responsiveness to gonadotropin-releasing hormone (GnRH). To this end, a test dose of GnRH was given to VAD rats pre-, 5 days post-, and 10 days postreplacement of vitamin A (PVA). In VAD rats, basal serum FSH and luteinizing hormone (LH) levels were higher than those of controls. Increased LH/testosterone ratios, both in basal levels and in the secretory response to GnRH, suggested Leydig cell hyporesponsiveness in VAD animals. Both the FSH and LH responses to GnRH were maximal at 1 h, declining thereafter. Although the absolute increments in FSH and LH 1 h after GnRH in VAD rats were greater than in controls, the percent increase in FSH tended to be lower in VAD rats and to increase after vitamin A replacement. The specific enhancement of FSH release PVA became evident only when assessing total secretion of FSH and LH after GnRH. Luteinizing hormone response to GnRH increased PVA, but not significantly, while FSH secretion after GnRH increased both 5 and 10 days PVA, times during which basal FSH levels were also increasing. These changes in FSH secretion could not be attributed either to increases in endogenous GnRH or to changes in testosterone or estradiol levels. Basal serum androgen binding protein levels, elevated in VAD animals, did not respond to the acute increases in FSH after GnRH and remained high PVA, suggesting no acute change in Sertoli cell function. Thus, the PVA increase in FSH secretion unmasks a partial inhibition of the gonadotrope present in the retinol-deficient, retinoic acid-fed male rat.

Diagnostic value of a single Widal test

The Widal test was performed on 90 blood specimens from typhoid fever patients, on 21 blood specimens from nontyphoid salmonellosis patients and on 46 nontyphoid febrile patients. Of 90 typhoid fever patients, 58 (64.4%) had H agglutinin titer of 1:160 or more and 55 (61.1%) had O agglutinin titer of 1:160 or more. Salmonella typhi H and/or O titer of 1:160 or more occurred in 70 (77.8%) of 90 typhoid fever patients and in 5 (23.8%) of 21 nontyphoid salmonellosis. Only one of the 46 (2.2%) nontyphoid febrile patients showed O agglutinin titer of 1:160, a case which was proven subsequently to be a case of systemic lupus erythematosus. Either O or H can reach to diagnostic level during the first week of typhoid fever, and can be helpful in diagnosis of the illness. In view of the high specificity (91.0%), sensitivity (77.8%) and accuracy (83.4%), the Widal test still has value in the diagnosis of typhoid fever.

Molecular cloning of Lyt-2, a membrane glycoprotein marking a subset of mouse T lymphocytes: molecular homology to its human counterpart, Leu-2/T8, and to immunoglobulin variable regions

The sequence of Lyt-2 cDNA shows that it is a new member of the immunoglobulin super gene family. Analysis of the predicted amino acid sequence indicates that the Lyt-2 polypeptide is synthesized with a 27-amino acid leader, and that the mature protein has an immunoglobulin variable region (Ig V)-related sequence of approximately 100 amino acids, an extracellular spacer of 43, a transmembrane region of 38, and an intracytoplasmic region of 27 amino acids. Lyt-2 and its human analogue Leu-2 are 56% homologous; analysis indicates that the Ig V-related domains of the two molecules have evolved away from each other faster than the carboxyl-terminal half of the proteins.

Postabortion insertion of the Nova T and MLCu250: preliminary results of a comparative study

This 4-year prospective randomized study is designed to compare the effectiveness and complication rates of the Nova T and MLCu250 inserted immediately postabortion. At the cut-off date (30 November 1983), all patients in the first cohort of 400 women had completed at least 12 months of use. At this stage of the trial, no significant differences had emerged between the two devices in any of the standard termination categories.

Corneal penetration behavior of beta-blocking agents I: Physiochemical factors

Rabbit corneas were excised and mounted in a chamber to determine the permeability characteristics of a group of beta-blocking agents which varied in octanol-water partitioning over a fourfold logarithmic range. From the permeability rate at steady state, permeability coefficients (pH 7.65) were determined. For each drug the distribution coefficient and pKa were measured, permitting the partition coefficients to be estimated. Various correlations were determined for the log permeability coefficient as a sum of log functions of the partition (or distribution) coefficient, molecular weight, and/or degree of ionization. The best fit, as judged by a high correlation coefficient (r = 0.9756) and lack of systematic deviation, was represented by: log PT = 0.623 log DC - 0.108(log DC)2 - 5.0268.

Corneal penetration behavior of beta-blocking agents III: In vitro-in vivo correlations

Aqueous humor levels were determined over time after the topical administration to rabbit eyes of 1% isotonic buffered (pH 7.3) solutions of three beta-blocking agents, acebutolol hydrochloride, timolol maleate, and bufuralol hydrochloride (arranged in order of increasing lipophilicity). Corneal permeability coefficients, determined from a previous in vitro study, were inversely related to the observed time to peak for the three drugs, as expected. Two of the drugs, bufuralol and timolol, did not give the expected rank order for Cmax and AUC, which could result from differences in distribution and/or elimination processes. Aqueous boundary layers were postulated for in vivo corneal permeability which suggested that bufuralol and timolol may have nearly identical effective permeability coefficients in vivo.

Corneal penetration behavior of beta-blocking agents II: Assessment of barrier contributions

Rabbit corneas were excised and mounted in a chamber to determine the permeability characteristics of a group of beta-blocking agents. By measuring the permeability rate of each drug across intact cornea, stroma alone, epithelium-stroma, and stroma-endothelium, it was possible to determine the resistance to penetration for each corneal layer. The reciprocal of the sum of resistances for the epithelium, stroma, and endothelium equaled the experimentally determined permeability coefficient for the intact cornea (104 +/- 6.0%). Thus, the penetration of beta-blocking agents through the excised rabbit cornea could be treated as three barriers in series. For hydrophilic compounds, the epithelium was the rate-determining barrier. The endothelium offered less resistance, whereas the stroma offered only very minimal resistance. The lipophilic compounds penetrated the excised cornea more rapidly. However, the stroma became rate-determining for the most lipophilic compounds (penbutolol, bufuralol, bevantolol, and propranolol). Although the octanol-buffer (pH 7.65) distribution coefficient of these compounds varied over a fourfold logarithmic range, the permeability coefficient was considered nearly constant [3.4 X 10(-5) (+/- 0.34) cm/sec] for stroma. Also, the ratios of tortuosity to porosity for the stromal layer were 1.58 +/- 0.15. These results suggest that drug diffuses through an aqueous media of gel-like mucopolysaccharide interspersed by a matrix of collagen fibrils. From further analyses intra- and intercellular pathways for epithelium and endothelium were added to the model resulting in a sigmoidal representation of permeability coefficient versus distribution coefficient. However, the intercellular (pore) pathway could not be adequately quantified because of the variation in the data for very hydrophilic compounds.

High performance liquid chromatographic analysis of supplemental vitamin E in feed

Supplemental vitamin E is extracted from feed in one step with methanol and analyzed by reverse phase partition chromatography in less than 10 min, using isocratic elution with either methanol or water-methanol as the mobile phase. Detection response (as measured by peak area) was linear between 0.5 and 3.0 mug, and the coefficients of variation for retention time and peak height on replicate analyses of the standard sample were 0.8 and 2.3%, respectively.