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Biomedical subjects

J Lang

Publications and source records attributed to J Lang.

At least 289 records · Page 16Linked to original sources
PubMed1990

The ophthalmic artery and its branches, measurements and clinical importance.

Seventy-one Caucasian orbits (36 right, 35 left) were studied by dissection. The diameter of the ophthalmic a. (2 mm from the origin) was 1.54 +/- 0.04 mm (male) and 1.31 +/- 0.05 mm (female). In individual cases, there were no significant differences in vessel diameter between the right and left sides but, differences in vessel diameter between males and females were more commonly observed in the arteries which leave the orbit (extraorbital group), the individual vessels having a larger diameter in males. The incidence of the ophthalmic a. passing in the orbit medially under the optic n. was 18.6%. The lacrimal a. was observed to arise from the ophthalmic a. in only 82.5% of the cases examined, 15.9% of the cases showed the origin to be at the anastomotic branch of the middle meningeal.

Adult↗
PubMed1990

On an intracranially divided optic nerve (N. opticus fissus).

An intracranially divided optic nerve is described for the first time. At its upper surface an adhesion of the arachnoid membrane and the medial frontobasal artery was seen. The finding is discussed with descriptions of earlier researches and results of our material.

Aged↗
PubMed1990

Liposomes composed of partially hydrogenated egg phosphatidylcholines: fatty acid composition, thermal phase behavior and oxidative stability.

Partially hydrogenated egg phosphatidylcholines (PHEPC) represent a new class of raw materials for liposome-based drug products. PHEPC were manufactured from native egg phosphatidylcholine (EPC) to iodine values (IV) 40, 30, 20, 10, and 1. Hydrogenation resulted in a complete loss of arachidonic acid (20:4) and docosahexaenoic acid (22:6) in IV 40 EPC and a progressive conversion of linoleic (18:2) and oleic acid (18:1) to stearic acid (18:0) at higher degrees of hydrogenation (IV 30, 20, 10, 1). Hydrogenation lead to formation of trans-fatty acid isomers maximally 18.5 mol% in IV 20 EPC. Liposomes made from IV 20, IV 10 and IV 1 EPC had marked phase transitions between 20 and 60 degrees C. PHEPC showed increased resistance to oxidation as measured by oxygen uptake during 2,2'-azobis-(2-amidinopropane) hydrochloride (AAPH) initiated accelerated oxidation. Various applications of these new materials in the manufacture of liposomes and liposome based drug products are discussed.

Chemical Phenomena↗
PubMed1990

[The region of the origin of the m. obliquus bulbi inferior].

A small depression usually develops immediately laterally to the entrance to the nasolacrimal canal, for the origin of the inferior oblique muscle. This depression is generally a part of the maxilla. In fetal material it was found that the development of this zone and of the lacrimal bone involves a more complex process than indicated in textbooks. In adults the inferior oblique muscle rises 1.54 mm (mean) laterally to the entrance to the canal and only 0.473 mm behind the inferior orbital rim of this area. The mean width of this muscle at its origin is 3.93:2.26 mm. The location of the muscle origin in relation to the orbital septum, its vascularization and possible causes of damage to its origin are pointed out.

Fetus↗
PubMed1990

[Genetic aspects of esotropia in homozygous twins].

The present paper reports on 14 pairs of monozygotic twins with ocular motility disorders. Eight pairs were concordant and two partially concordant, while four pairs were discordant. Four pairs were born prematurely; two pairs were born by cesarean section, one of them also prematurely. Of the 24 patients with motility disorders, 10 had congenital squint syndrome, nine microtropia, one accommodative esotropia, two esophoria, and two orbital strabismus due to premature synostosis of the coronal suture. Genetic and exogenic factors and the forms of strabismus are discussed.

Adolescent↗
PubMed1990

How adolescents compare AIDS with other diseases: implications for prevention.

Four hundred ten adolescents, ages 14-16 years, completed a questionnaire concerned with their understanding of the social and emotional consequences of AIDS and 5 other illnesses (lung cancer, German measles, chicken pox, asthma, and diabetes). Pupils distinguished between the diseases on all measured items, but younger pupils were more likely to believe that individuals were personally responsible for the onset of AIDS, lung cancer, and diabetes. The data are discussed in terms of the implications for health education campaigns.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Prolonged survival of renal transplants in nonimmunized and hyperimmunized rats receiving a platelet-activating factor antagonist.

A potent platelet-activating factor (PAF) antagonist, RP 48740, was tested for its ability to delay acute and accelerated rejection in experimental kidney transplantation. Lewis rats (RT1(1] either nonimmunized or preimmunized against Brown Norway (BN) antigens, received allogeneic kidney transplants from BN rats (RT1n) and were bilaterally nephrectomized. Survival of transplanted animals was observed following oral treatment with RP 48740 (100 mg/kg/day). Control animals received orally methylcellulose 5% (placebo), cyclosporine (10 mg/kg/day), or CsA (10 mg/kg/day) plus RP 48740 (100 mg/kg/day). CsA prolonged rat survival in both rejection models. RP 48740 induced prolongation of survival in preimmunized rats and, to a lesser but significant degree, in nonimmunized animals. Although treatment with CsA plus RP 48740 was efficient in acute rejection, it induced no significant increase of survival in preimmunized rats as compared with placebo, indicating a lack of potentiating activities between the two compounds. The pharmacokinetic study of CsA showed that this lack of efficacy of combined treatment may be interpreted as the decreased CsA bioavailability observed when the animals also received RP 48740. The demonstration that a PAF antagonist delays accelerated rejection sheds some light on the biological effects of hyperimmunization in transplantation and on the possible therapeutic approaches.

Animals↗
PubMed1990

Clinical anatomy of the blood spaces and blood vessels surrounding the siphon of the internal carotid artery.

The anterior blood space of the cavernous sinus is situated anterolateral to the carotid siphon in 70%, anterior to it in 15%, and lateral to it in 15%. Its height, depth, and mediolateral breadth were measured. The mean distance between the carotid siphon and the skin at the supraorbital foramen was measured with 63 (52.4-71.4) mm. The drainage of the orbital veins was studied and described as well as the area of origin and first course of the ophthalmic artery and its clinical importance.

Carotid Artery, Internal↗
PubMed1990

[The vascularization of the vagina bulbi].

The construction of the vagina bulbi was examined in injection preparations with the aid of microdissection methods, and its layers were defined. Inside the connective tissue leaves occur loop capillaries up to 14 mm in length. The course of the venae vorticosae through the vagina bulbi as well as the width of the episcleral vessel network were measured. Also the subconjunctival network and arteries and nerves perforating sclera were studied. The ascertained results are discussed with former and recent anatomical and clinical reports.

Adult↗
PubMed1990

[Clinico-anatomical findings of the nasodental nerve].

To avoid neuralgic pain as consequence of damaging the nasodental nerve during surgical treatment of chronic maxillary sinusitis by the Caldwell-Luc-approach, the accurate knowledge of the nasodental nerve's course might be useful for the surgeon. Therefore, the anatomy of this nerve was evaluated by dissection of 23 human specimens. The nasodental nerve is the largest single branch of the infraorbital nerve's Rr. alveolares superiores anteriores. The first course of the nasodental nerve in the roof of the maxillary sinus has a (mean) length of 14 mm on the right and 16 mm on the left side. Mostly it accompanies the infraorbital nerve in the canalis infraorbitalis and leaves this common channel 4 mm on the right and 6 mm on the left behind the infraorbital foramen. The next part of the nerve, which is orientated from laterocranial to mediocaudal, is found in the front wall of the antrum Highmori and has a length of 18 mm at the right and 20 mm at the left. Next it leaves the sinus through a tiny channel at the angle between the front and the medial wall of the maxillary sinus. On the last course, the nerve runs in the lateral wall of the nose 8 mm at the right and 9 mm at the left behind the rim of the apertura piriformis.

Aged↗
PubMed1990

Spontaneous association between opioid receptors and GTP-binding regulatory proteins in native membranes: specific regulation by antagonists and sodium ions.

High affinity GTPase in membranes from NG108-15 cells was differentially affected by opioid competitive antagonists; one type of antagonist [( N,N'-diallyl-Tyr1-Aib2,3]Leu-enkephalin) reduced the basal rate of GTP hydrolysis, whereas a second type (MR 2266) produced no changes. The inhibitory effect of the "active" antagonist was stereospecifically reversed by the "inactive" antagonist, indicating that it was receptor mediated. This suggests that part of basal GTPase activity in this system results from a spontaneous interaction between opioid receptors and GTP-binding proteins (G proteins) and that some antagonists exhibit negative intrinsic activity by hindering such an interaction. The inhibitory effect of the antagonist was minimal in the presence of Na+ and maximal when Na+ was replaced by K+ in the reaction. When the ratio [Na+]/[K+] was progressively increased at constant [Cl-], total GTPase activity (i.e., net difference between activity stimulated by agonist and that inhibited by antagonist) did not change, but the activity measured in the absence of ligand was selectively decreased. Thus, Na+ does not alter the total proportion of G proteins that can be activated by ligand-occupied receptors and instead regulates the interaction between receptor and G protein in the absence of ligand. Upon examination of several opioid agonist and antagonists, we found an inverse relation between the intrinsic activity (either negative or positive) of each ligand and the sensitivity to Na+ of the GTPase elicited upon occupation of the receptor by that ligand. Sodium-mediated and ligand-mediated regulations of GTPase had identical requirements for Mg2+ [( Mg2+]free greater than 10 microM), and were both abolished with a similar potency by pertussis toxin. There was no effect of Na+ on the basal rate of GTP hydrolysis of Gi/Go purified from bovine brain. However, addition of these proteins to membranes prepared from cells that had been previously exposed to pertussis toxin partially restored both receptor- and sodium-mediated regulations of GTPase in parallel and in a concentration-dependent fashion. We conclude that sodium ions play a key role in the mechanism underlying the spontaneous interaction between "empty" receptors and G proteins in intact membranes.

Animals↗
PubMed1990

Lack of concordance in classification of coronary heart disease risk: high-risk HDL cholesterol less than 35 mg/dl in subjects with desirable total serum cholesterol, less than 200 mg/dl.

In using National Cholesterol Education Program guidelines (for desirable low risk, a total cholesterol level less than 200 mg/dl, and for high risk, a level of high-density lipoprotein cholesterol (HDLC) less than 35 mg/dl), our specific aim was to examine lack of concordance in classification of coronary heart disease (CHD) risk by HDLC less than 35 mg/dl in subjects with total cholesterol less than 200 and to determine whether lack of concordance increased as group CHD risk increased. We studied four cohorts ranging from putatively low to high CHD risk. These included self-referred subjects in a public urban total cholesterol screening (n = 897), hospitalized patients with depression (n = 144), Cholesterol Center referrals at presumed high CHD risk (n = 1120), and patients having coronary arteriography (n = 145) because of presumed coronary artery disease. Total cholesterol was less than 200 mg/dl in 25% of subjects from the urban sampling, in 54% of hospitalized patients with depression, in 27% of Cholesterol Center referrals, and in 41% of those undergoing cardiac catheterization. In these four cohorts, of subjects with total cholesterol less than 200, 7%, 26%, 25%, and 48%, respectively, had HDLC less than 35 mg/dl. The likelihood of having total cholesterol less than 200 and HDLC less than 35 mg/dl was 1.7% in urban public subjects, 6.8% in Cholesterol Center referrals, 13.9% in depressed patients, and 20% in cardiac catheterization patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Cholesterol↗
PubMed1989

Cyclosporine (cyclosporin A) pharmacokinetics in renal transplant patients receiving ciprofloxacin.

The effects of ciprofloxacin administration on the pharmacokinetic parameters and biologic tolerance of cyclosporine (cyclosporin A) were determined in primary renal transplant patients. This study was performed in 10 patients (four women and six men) ranging in age from 26 to 64 years and body weight ranging from 46 to 88 kg. Ciprofloxacin therapy was started eight to 48 days (mean, 21 days) after transplantation, whereas the cyclosporine therapy was administered for seven to 48 days (mean, 18 days) post-transplant. Both ciprofloxacin and cyclosporine were administered every 12 hours. The mean cyclosporine dosage was 2.4 mg/kg per day, adjusted to obtain blood concentrations within the recommended range (i.e., 100 to 200 ng/ml). The ciprofloxacin dosage was 750 mg orally twice daily for all patients. A pharmacokinetic study of cyclosporine was performed in each patient the day before starting ciprofloxacin treatment and after the 13th ciprofloxacin administration (i.e., Day 7 of ciprofloxacin therapy). Cyclosporine concentrations were measured in whole blood by a specific high-performance liquid chromatography method and the following parameters were determined: minimal and maximal blood concentrations, area under the curve from zero to 12 hours, total body oral clearance, mean residence time, and elimination half life. Concurrently administered medications and serum creatinine values were recorded. No statistically significant difference was noted between the cyclosporine pharmacokinetic parameters before and during ciprofloxacin treatment. Serum creatinine levels were increased in four of 10 patients, but the increase was not considered related to ciprofloxacin treatment. In conclusion, it appears that ciprofloxacin can be administered to renal transplant patients without risk of interacting cyclosporine or enhancement of cyclosporine nephrotoxicity. Additional cyclosporine blood level monitoring is not particularly valuable in this setting.

Adult↗
PubMed1989

Purification and characterization of subforms of the guanine-nucleotide-binding proteins G alpha i and G alpha o.

Five different pertussis-toxin-sensitive guanine-nucleotide-binding proteins (G proteins) were purified from bovine brain. Immunochemical characterization of alpha subunits identified two G alpha o proteins (G alpha o-I and G alpha o-II), two 41-kDa G alpha i proteins (G alpha i-I and G alpha i-II) and the 40-kDa G alpha i2 protein. Site-directed antisera specific for G alpha o proteins did not differentiate between G alpha o-I and G alpha o-II. However, in situ peptide mapping using polyacrylamide gel electrophoresis revealed distinct cleavage products with different proteases for each of these proteins. Additionally comparison of Rf values demonstrated a slightly faster migration for G alpha o-II than for G alpha o-I, which is the only type of G alpha o protein present in cell membranes of the neuroblastoma/glioma cell line NG 108-15. The importance of these structural differences and possible functional implications are discussed.

Animals↗