Intraocular lenses: complications and visual results

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Comparison of oral propranolol and verapamil for combined systemic hypertension and angina pectoris. A placebo-controlled double-blind randomized crossover trial

The relative efficacies of oral verapamil, a calcium-entry blocking drug, and propranolol, a beta-adrenergic blocking drug, were compared in 12 patients who had both stable angina pectoris and mild to moderate systemic hypertension, using a placebo-controlled, double-blind, randomized crossover protocol. Compared with placebo, both propranolol and verapamil decreased the frequency of anginal attacks and the number of nitroglycerin tablets consumed, and increased exercise duration and total work; there were no significant differences in the antianginal effect of the two drugs. Both verapamil and propranolol reduced the supine and standing systolic and diastolic blood pressure measured at rest; compared with propranolol, however, verapamil had greater effects on standing diastolic blood pressure (p less than 0.002). Resting heart rate was reduced from placebo baseline with large doses of both drugs; compared with verapamil, however, propranolol exerted greater effects on resting heart rate and rate-pressure product. Plasma renin activity was increased from placebo baseline with verapamil (p less than 0.05), but was reduced with propranolol (p less than 0.05); no significant change in plasma aldosterone was seen with either drug. Verapamil appears to be a safe and effective treatment alternative to propranolol for relieving anginal symptoms, improving exercise tolerance, and reducing elevated systemic blood pressure in patients with both angina pectoris and mild to moderate systemic hypertension.

Comparative effects of abrupt withdrawal of propranolol and verapamil in angina pectoris

The potential hazards of abrupt withdrawal of propranolol have been described in patients with angina pectoris; however, the effects of abrupt withdrawal from long-term therapy with verapamil have not previously been investigated. The comparative effects of withdrawal from long-term treatment with propranolol and verapamil were assessed in a placebo-controlled double-blind randomized crossover study of 20 patients received placebo for 2 weeks, then increasing doses of propranolol (60 to 320 mg/day) or verapamil (240 to 480 mg/day) for 3 weeks. Patients were then abruptly withdrawn from drug onto placebo for 1 week, followed by crossover to the other drug treatment and a second withdrawal period. All 20 patients were withdrawn from verapamil without evidence of a rebound increase in frequency of anginal attacks, blood pressure, heart rate, or rate-pressure product and without a rebound deterioration in exercise tolerance. In contrast, with propranolol withdrawal, 2 patients (with the highest baseline angina attack rate) had a severe exacerbation of their anginal syndrome and could not undergo formal exercise testing; the other 18 patients were withdrawn from propranolol without incident. Plasma catecholamines were increased during exercise compared with rest during all treatments; however, the levels of catecholamines during exercise were significantly higher with propranolol than with verapamil and placebo (p less than 0.05). Levels of exercise catecholamines returned to placebo baseline values after withdrawal of propranolol.

A mathematical model of B lymphocyte differentiation: control by antigen

A mathematical model of B lymphocyte differentiation, based on experimental results, has been developed. The model focuses on the role of antigen in initiating and regulating B cell differentiation while other mechanisms, acting in concert with antigen but the functioning of which can be circumvented under appropriate conditions, are not considered. The importance of presence of antigen at individual stages of B cell differentiation was studied in experiments with an easily metabolizable antigen. Immunocompetent cells (ICC), arising by antigen-independent differentiation of stem cells, are activated by antigen (they become immunologically activated cells--IAC). Excess of antigen drives IAC into the terminal stage (antibody-forming cells--AFC) thereby restricting proliferation. Exhaustive terminal differentiation results in tolerance. A low primary dose permits IAC to escape antigen; IAC proliferate and later give rise to resting memory cells (MC) which are amenable to reactivation. MC have higher avidity for antigen (due to higher affinity, number and density of receptors) and the effect of different doses of antigen on MC is diverse. A very low secondary dose induces tolerance, a medium dose secondary response, and the administration of a high dose of antigen also brings about tolerance. The model suggests that the fate of memory cells is controlled by the ratio R:Ag, of the number of immunoglobulin receptors on B cells (R) to the number of available antigenic molecules (Ag), low values R:Ag favouring stimulation to differentiation while high values of R:Ag favouring inactivation. A nonlinear system of ordinary differential equations, describing the development of the populations involved in antigen-driven B cell differentiation, was used to simulate experiments and good qualitative agreement was achieved.

pH Determination in Acidified Foods: Collaborative Study

A proposed method for determining pH of acidified foods has been developed and subjected to collaborative study. The method appears to be both accurate and precise. Five samples consisting of pimientos, marinated pimientos, 2 pH buffer solutions, and chocolate syrup were sent to each of 12 collaborators along with a copy of the method. Two of the collaborators were FDA District laboratories while the remainder were representatives from industry, universities, and state health agencies. Many different types of pH meters and combinations of electrodes were used by the collaborators. The tabulated results from the collaborators are presented. The method has been adopted official first action.

Mathematical models of antibody response

An antigen triggers the clonal expansion of B lymphocytes accompanied by antibody production. This paper presents and compares the basic ideas of three mathematical models of B cell differentiation and proliferation.

Isolation and characterization of the thymus-brain antigen (analogous to thy-1 antigen) from human brain

1. The human thymus-brain antigen, which corresponds to the murine (mouse or rat) Thy-1 antigen complex, was isolated from brain after solubilization in deoxycholate by gel-permeation chromatography, wheat-germ-lectin affinity chromatography and ion-exchange chromatography. 2. The isolated antigen is a glycoprotein displaying an apparent molecular weight of 26 000-29 000 in sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. 3. No antigen activity was found with the lipid fraction from human brain. 4. The protein has a tendency for spontaneous self-association (dimerization), leading to aggregates resistant to dissociating and reducing agents on prolonged storage. 5. The antigen is microheterogeneous with respect to size, charge (approximate isoelectric points of the monomer 7.7, 7.0 and 6.5) and to lectin-binding affinity. 6. The antigen can be reconstituted to protein-lipid vesicles. The antigen activity of solubilized antigen is strongly increased by reconstitution and that of membranes decreased by solubilization with detergent.

Chronopharmacology: a therapeutic frontier

Chronopharmacology, the study of time-dependent physiological response to drugs, and its relationship to current drug therapy are discussed. The objective of chronotherapy is to apply chronobiologic principles to the treatment of human disease. The appropriate patients for chronotherapy are those who are receiving high-risk drugs, who have a high-risk disease (e.g., cancer) or who are receiving a high-cost drug. Although little is known of the chronobiologic characteristics of many drugs or diseases, researchers should take into account the possible relationship of chronobiology to drug effects when designing therapeutic trials. Drug therapy can be optimized by tailoring dosing schedules and distribution systems to chronobiologic patterns.

[Use of tests based on the analysis of expired air in nutritional studies]

Tests based on the analysis of the gaseous components of expired air have been developed to study intestinal absorption and intermediary metabolism of various nutrients. This paper reviews the breath-analysis tests based on the measurement of CH4, H2, and isotopically-labelled CO2 for studying the intestinal absorption of carbohydrates, fats, and bile salts, and intrahepatic metabolism. New technology employing mass spectrometry allows the use of the stable isotope, carbon-13, instead of the radioactive isotope, carbon-14, for CO2 breath tests. The nutritional application of the breath-analysis tests is discussed, and the advantages of the non-radioactive, non-invasive procedures, especially for use in children and pregnant women in whom standard investigational methods represent a discomfort or a radioactive hazard, are emphasized.

Phase II clinical trial with high-dose methotrexate therapy and citrovorum factor rescue

One hundred and thirty-four patients with advanced malignant disease were treated with 496 infusions of high-dose methotrexate (HD-MTX) followed by citrovorum factor rescue. Most patients had failed to respond to previous combination chemotherapy. The overall response rate was 29% with 33 partial responses and six complete responses observed in patients with a variety of tumors. Plasma MTX levels were monitored in all patients during each course of therapy in order to identify those patients with delayed plasma MTX clearance. Patients with abnormally slow rates of plasma MTX decay received escalated doses of citrovorum factor rescue in order to prevent drug-induced toxicity. In general, during this study HD-MTX was well-tolerated. Because serious toxicity was neither frequent, severe, nor unpredictable, its use was not limited. HD-MTX should now be evaluated in well-designed controlled clinical trials to compare its antitumor activity to that of conventional- or standard-dose MTX regimens in diseases where HD therapy appears to have efficacy.

Serological and chromatographic analyses of antigenic structures detected in human brain, thymus and lymph nodes

In the present paper it is shown that the non-species specific determinant of the antigenic thymus-brain system previously detected in murine and human brain also exists in human thymus. However, in contrast to the situation in mice and rats this antigenic structure is not expressed on suspended thymic lymphocytes, but is associated with thymic tissue largely depleted of thymic lymphocytes. Moreover, this determinant is also detectable in human lymph nodes. Besides the non-species-specific antigenic determinant human thymus and brain also share a species-specific determinant. In contrast to the non species specific determinant this structure is also displayed by suspended thymic lymphocytes, certain peripheral blood lymphocytes and bone marrow cells. The non-species-specific determinant detected in human thymus is borne by a structure, which physico-chemically resembles the thymus-brain antigen isolated from murine brain and thymus as well as from human brain. Although the structure bearing the species specific antigenic determinant has a similar apparent molecular weight both antigens could be separated by ion exchange chromotography indicating their molecular diversity.

[Cultivation of the epithelium in burns]

Comparison of two groups of burned patients shows that patients who were treated by wound solution stayed a significantly shorter time in hospital. The group with healing under the scab (PQB) had indeed slighter skin lesions, but syated a much longer time in hospital. The great advantage of treatment of burned wounds with wound solution is seen in the relief of pain of the patients. Aslo, physical exercises can begin immediately. Wound solution needs no anaesthesia for necrolysis. The shortening of the healing time results in stimulation of the marginal epithelium and growth of autologous transplanted cells on the wound.

[New method for security by colon anastomoses (author's transl)]

After examinaning the vascular supply of the parietal peritoneum helved peritoneal flaps were fixed in wound dehiscent colon anastomoses. If the vascular supply to the peritoneal flap was sufficient all animals survived without signs of stenosis. It was proved by microangiographic studies that there was an additional vascular supply to the anastomosed colon by the artery of the peritoneal flap.

Solubilization and molecular characterization of membrane-bound antigens shared by thymocytes and brain

In order to characterize chemically the serologically well-defined antigens shared by thymocytes and nervous tissue of mice and rats, different solubilization procedures have been tested. Treatment of thymocyte membranes with urea-Nonidet-P40 (NP40) proved to be the most valuable method, since nearly 100% of the antigen was solubilized essentially without loss of the antigenicity. By gel filtration in urea-NP40 the molecular weight was estimated to be 35 000 and the Stokes radius in sodium deoxycholate 31.8 A. In gel filtration studies a homogenous peak was obtained, whereas isoelectric focusing yielded two peaks (isoelectric points pH 4.5-5.0 and pH 5.4). The three determinants of this antigenic system were inseparable in gel filtration and isoelectric focusing, supporting the view put forward on the basis of serological studies that they are part of the same molecule. Extraction of murine thymocyte membranes with organic solvents yielded a considerable loss of activity of the thymocyte-brain antigen. There was some residual activity in the protein fraction, but none in the organic phase. Correspondingly, the highly purified ganglioside G Gtet 2b proved unable to absorb any rabbit anti-CBA brain serum. The reduced antigenic activity of the delipidated protein fraction could be restored by addition of lipids, as well as the nonionic detergent NP40. These observations suggest that interaction of protein and lipid is necessary for the antigenicity of the thymocyte-brain antigen.

[Antibody differentiation in human toxoplasmosis experiments on model cases (author's transl)]

Human sera with antibodies against Toxoplasma gondii were investigated-before and after gel filtration (Sephadex G 200)-by IgM-and IgG-specific immunofluorescent reactions as well as well by complement fixation tests.-In sera from patients with "latent" infections IgM-antibodies could not be demonstrated neither by the IgM-IFT-nor the CFT technique, although IgG antibodies with IFT titres between 1:50 qnd 1:200 were present.-In sera from patients in the "acute" stage of infection both IgM and IgG antibodies were always found. In some cases the IgG fraction had complement fixing properties only, although IgM antibodies were present as demonstrable by the IFT technique. -These observations leed to the possibility of immunologic differentiation between IgM-IFT and CF-antibodies. The role of the different antibodies in the serodiagnosis of human toxoplasmosis is discussed.

Bile salt metabolism in the human premature infant. Preliminary observations of pool size and synthesis rate following prenatal administration of dexamethasone and phenobarbital

Bile salt synthesis and bile salt pool size were determined by isotope dilution in two groups of healthy premature infants, utilizing nonradioactive deuterium-labeled bile salts. All 9 infants were between 32 and 36 weeks of gestation; however, in one group (4 infants), the mothers had received either dexamethasone or phenobarbital prior to delivery. The total bile salt pool averaged 20 mg for the infants of untreated mothers and 79 mg for the infants of treated mothers; similarly, the bile salt synthesis of 8 mg per day in the untreated group was increased to 27 mg per day for the treated group. Expressed per sq m of body surface, the cholic acid pool for the treated group was 321 mg per sq m, and the cholic acid synthesis rate equaled 98 mg per sq m per day; values equal to those for full term infants and nearly 4 times those for the untreated prematures. The intraduodenal bile salt concentrations obtained during meals were also low in the untreated group, equaling 1.2 mM as compared to 5.3 mM for the treated group. The reductions of bile salt pool size, synthesis, and intestinal concentration establish that the functional maturity of the liver, and possibly the gastrointestinal tract, is reduced in premature infants. The results further suggest that this maturity may be dramatically influenced by medications administered to the mother prior to delivery.

Successful application of prenatal diagnosis in a pregnancy at risk for homozygous beta-thalassemia

A Sicilian couple whose first child had homozygous beta-+-thalassemia requiring monthly transfusion requested prenatal diagnosis during the second pregnancy. Fully informed consent was obtained. The placenta was localized by ultra-sound at the 20th week of gestation, and was aspirated with a 20-gauge needle. Samples containing fetal red cells were obtained, and studies of globinchain synthesis showed a normal beta/gamma synthesis ratio for this gestational age. The conclusion that the child was not affected by beta-thalassemia was confirmed when an infant not affected with homozygous of heterozygous beta-thalassemia was born at term. Although more experience with this approach is necessary, this study demonstrates that prenatal diagnosis or exclusion of beta-thalassemia and sickle-cell anemia is feasible.

Vitamin A acid and wound healing

After preparatory treatment with 1% vitamin A acid for 3 days, healing of standardized wounds was accelerated by 18%, compared with a control group. The histological findings revealed as causes a general activation of epidermis, resp. signs of proliferation with inhibition of normal differentiation and hornification. These well known alterations due to vitamin A acid treatment are clearly visible in all epidermal layers. Obviously the activation of epidermis occurs when a remainder of the wound normally is healing by epithelization, that is at an area of 50 mm2. The profit of time in this sense can be defined unequivocally from the performed animal experiments.

Comparison of mitotic phenomena and effects induced by hypertonic solutions in HeLa cells

Interphase HeLa cells exposed to solutions that are 1.6 x isotonic manifest a series of morphological transformations, several of which grossly resemble those which occur when untreated cells enter prophase. These include chromosome condensation with preferential localization at the nuclear envelope and nucleolus, ruffling of the nuclear envelope, and polyribosome breakdown. The nucleolus loses its fibrous component and appears diffusely granular. At 2.8 x isotonicity the nuclear envelope is selectively dispersed although other membranes show morphological alterations also. The characteristic transitions of the lysosomes, Golgi complex, and microtubules seen in normal mitosis do not occur during hypertonic treatment. All the changes induced with hypertonic solutions are rapidly reversible, and the nucleus particularly goes through a recovery phase which bears some similarity to that of the telophase nucleus. The prophase-like condensation of the chromatin following exposure of the intact cell to hypertonic medium cannot be reproduced on an ultrastructural level in the isolated nucleus with any known variation in salt concentration, suggesting significant modifications of the nuclear contents during isolation. In addition to these morphological responses, hypertonic solutions also markedly and reversibly depress macromolecular synthesis. The polyribosome disaggregation that results from exposure to hypertonic solutions may be partially prevented by prior exposure to elevated Mg(++) concentrations; this same ion is also partially effective in preventing the polyribosome breakdown which normally occurs as cells enter mitosis.