Clinicopathologic observations of a silicone posterior chamber lens in a primate model

A primate model was used to compare a silicone intraocular lens (Elastic Lens, STAAR Surgical) and a conventional polymethylmethacrylate/polypropylene lens. Tolerance and stability of silicone lenses within the eye were tested.

Balloon dilatation of the prostatic urethra. Work in progress

Balloon dilatation of the prostatic urethra was performed in eight dogs and one human with benign prostatic hyperplasia. This was done in vivo in six dogs and in vitro in two dogs and one human. Follow-up study at 1-23 weeks showed persistent dilatation, which was documented both radiographically and pathologically. Technical improvements limited complications to the early phase of the study. While results are encouraging, extrapolation to humans is difficult.

In vivo and in vitro studies of the binding of antibody/dsDNA immune complexes to rabbit and guinea pig platelets

The in vivo and in vitro binding of prepared antibody/dsDNA immune complexes to rabbit and guinea pig cellular blood components was examined. The in vitro binding in these two nonprimates was almost entirely due to platelets, and required homologous, intact complement; furthermore, no appreciable binding was observed for neutrophils, mononuclear cells, or erythrocytes at normal blood concentrations. The in vivo binding reaction occurred quite rapidly (less than 1 min for maximal binding) and the majority of the injected counts were cleared from the circulation in 3 to 5 min. Over this time period, however, a large fraction of the counts remaining in the circulation also remained bound to the animals' cells (presumably platelets), and this result was most pronounced for complement-fixing immune complexes prepared with high m.w. dsDNA. In vitro studies confirmed that immune complexes prepared with such dsDNA are rather slowly released from the animal platelets in the presence of homologous serum, and this result is in marked contrast to the considerably greater lability of bovine serum albumin/anti-bovine serum albumin immune complexes that are bound to complement receptors on animal and human cells. These observations suggest that the fate of immune-complexed dsDNA in the circulation may be very different from that of free dsDNA, and in the case of nonprimates may involve a platelet-mediated immune complex clearance mechanism analogous to the erythrocyte-mediated immune complex clearance mechanism which is believed to be operative in primates.

In vivo and in vitro studies of the binding of antibody/dsDNA immune complexes to rabbit and guinea pig platelets

The in vivo and in vitro binding of prepared antibody/dsDNA immune complexes to rabbit and guinea pig cellular blood components was examined. The in vitro binding in these two nonprimates was almost entirely due to platelets, and required homologous, intact complement; furthermore, no appreciable binding was observed for neutrophils, mononuclear cells, or erythrocytes at normal blood concentrations. The in vivo binding reaction occurred quite rapidly (less than 1 min for maximal binding) and the majority of the injected counts were cleared from the circulation in 3 to 5 min. Over this time period, however, a large fraction of the counts remaining in the circulation also remained bound to the animals' cells (presumably platelets), and this result was most pronounced for complement-fixing immune complexes prepared with high m.w. dsDNA. In vitro studies confirmed that immune complexes prepared with such dsDNA are rather slowly released from the animal platelets in the presence of homologous serum, and this result is in marked contrast to the considerably greater lability of bovine serum albumin/anti-bovine serum albumin immune complexes that are bound to complement receptors on animal and human cells. These observations suggest that the fate of immune-complexed dsDNA in the circulation may be very different from that of free dsDNA, and in the case of nonprimates may involve a platelet-mediated immune complex clearance mechanism analogous to the erythrocyte-mediated immune complex clearance mechanism which is believed to be operative in primates.

Dual-origin plasmid vectors whose origin of replication is controlled by the coliphage lambda promoter pL

The insertion of an XhoI linker 30 bp from the 5' end of the RNA II primer for ColE1 plasmid replication has allowed us to replace the natural RNA II promoter by other controllable promoters, in particular lambda pL. Manipulation of this modified origin was facilitated by constructing dual-origin plasmids, stable maintenance being directed by the pSC101 origin. Experiments showed that such dual-origin plasmids could be stably maintained at approximately four copies per chromosome at 30 degrees C and readily amplified by thermal induction of strains carrying a thermolabile lambda repressor. The use of such plasmids for the construction of stable, amplifiable expression vectors is discussed.

Effect of a self-care education program on medical visits

A prospective, randomized, controlled trial of self-care educational interventions was conducted in a health maintenance organization to determine their effect on ambulatory care utilization. Statistically significant decreases in total medical visits and minor illness visits were found in each of three experimental groups as compared with a control group. These decreases averaged 17% and 35%, respectively. These results were most clearly linked to a system of written communications emphasizing personal decision making about the use of medical care. The addition of a nurse counseling session to the written materials may increase cost savings and appears to be attractive to "high utilizers." A telephone information service was offered but not used. It is estimated that the decreases in utilization could result in a savings of approximately $ 2.50 to $ 3.50 for each dollar spent ona nurse counseling session to the written materials may increase cost savings and appears to be attractive to "high utilizers." A telephone information service was offered but not used. It is estimated that the decreases in utilization could result in a savings of approximately $ 2.50 to $ 3.50 for each dollar spent on the educational interventions. Self-care education systems may have important effects on medical care costs, physician satisfaction, and patient confidence.

The effect of testosterone on human chorionic gonadotropin-stimulated ovarian steroidogenesis in vivo in the baboon (Papio cynocephalus)

We have studied the effect of exogenously induced hyperandrogenism on the ovarian response to human chorionic gonadotropin (hCG) in the baboon. Normally cycling baboons were treated with increasing daily doses of hCG for 5 consecutive days from day 10 of the luteal phase (n = 5). Hyperandrogenic baboons received the same hCG regimen 1 hour after a Silastic capsule containing crystalline testosterone (T) had been implanted under the skin (n = 3). Control animals received an empty Silastic capsule (n = 8). All baboons were bled on alternate days from days 6 to 20 of the luteal phase, and daily during hCG treatment. T capsules induced immediate hyperandrogenism, with T levels several times greater than normal luteal phase levels. The use of hCG resulted in an increase in plasma progesterone within 24 hours and levels gradually declined thereafter. Estradiol increased rapidly and remained elevated during hCG treatment. In the presence of elevated T levels, hCG had a significantly reduced effect on the magnitude and duration of plasma progesterone increase. The effect of hCG on plasma estradiol levels was virtually eliminated in hyperandrogenic baboons. This study seems to demonstrate a direct inhibitory effect of T on ovarian steroidogenesis in vivo and may explain the ovarian changes that occur in hyperandrogenic women.

Lactate dehydrogenase activity as measured by the SMAC is related to flow-cell energy

Determination of lactate dehydrogenase (LDH) activity in the SMAC (Technicon) is based on the change in NADH absorbance between two flow cells. We noted that results for patients' specimens and controls changed when the fiber optic terminations for the two LDH channel flow cells were adjusted or "peaked" at the colorimeter chopper assembly. The energy (intensity) of light reaching the flow cells was varied by adjusting the fiber optic terminations, and the absorbance readings for a series of solutions containing NADH and patients' specimens were recorded. For both flow cells, when the fiber optic terminations were adjusted to increase the zero absorbance light intensity from 20 lines to 60 lines, a significant (p less than 0.0001) proportional change was seen in the absorbance readings. Evidently the difference in absorbance between the two flow cells is related not only to the NADH concentrations but also to the difference in the light intensity at the two flow cells. Consequently, changes in the adjustment of the fiber optic terminations produce systematic changes in results for LDH in patients' sera. These systematic changes in LDH results may be minimized by maintaining equivalent settings of the fiber optic terminations for the two flow cells and by using the calibration material with an absorbance most similar to that of patients' specimens.

Lactate dehydrogenase activity as measured by the SMAC is related to flow-cell energy

Determination of lactate dehydrogenase (LDH) activity in the SMAC (Technicon) is based on the change in NADH absorbance between two flow cells. We noted that results for patients' specimens and controls changed when the fiber optic terminations for the two LDH channel flow cells were adjusted or "peaked" at the colorimeter chopper assembly. The energy (intensity) of light reaching the flow cells was varied by adjusting the fiber optic terminations, and the absorbance readings for a series of solutions containing NADH and patients' specimens were recorded. For both flow cells, when the fiber optic terminations were adjusted to increase the zero absorbance light intensity from 20 lines to 60 lines, a significant (p less than 0.0001) proportional change was seen in the absorbance readings. Evidently the difference in absorbance between the two flow cells is related not only to the NADH concentrations but also to the difference in the light intensity at the two flow cells. Consequently, changes in the adjustment of the fiber optic terminations produce systematic changes in results for LDH in patients' sera. These systematic changes in LDH results may be minimized by maintaining equivalent settings of the fiber optic terminations for the two flow cells and by using the calibration material with an absorbance most similar to that of patients' specimens.

The effects of diet on high density lipoprotein cholesterol

Twenty-nine patients with normal blood lipids were placed on diets. Thirteen, mainly attending hospital for varicose veins, were prescribed low-energy diets: HDL-cholesterol was raised after one month and significantly after three months (P less than 0.02); total cholesterol was lowered (P less than 0.05). Sixteen patients, mainly with irritable bowel symptoms, were prescribed high-fibre diet: HDL-C was raised after one month (P less than 0.05), but not significantly so after three months; total cholesterol was unchanged.

The effects of season and temperature on D-lactate dehydrogenase, pyruvate kinase and arginine kinase in the foot of Helix pomatia L

The effects of pH, season, environmental and experimental temperatures on the activities and kinetic parameters of D-lactate dehydrogenase, pyruvate kinase and arginine kinase from the foot of the pulmonate snail Helix pomatia were analyzed. Both in phosphate and Tris buffers D-lactate dehydrogenase was the enzyme with the most acid maximum, arginine kinase that with the most alkaline, whilst pyruvate kinase occupied an intermediate position. Pyruvate kinase activity, measured at 20 degrees C, was positively correlated with the environmental temperature at the moment of collecting the animal, whereas neither arginine kinase nor D-lactate dehydrogenase showed such a relationship. A seasonal study based on approximately 100 specimens established that arginine kinase activity remained the same throughout the year. Pyruvate kinase activity was slightly lower, and D-lactate dehydrogenase activity significantly higher, in winter than in summer animals. Snails subjected in spring to a short warm-up period before enzyme extraction showed extreme variability and some extraordinarily high values of pyruvate kinase activity, suggesting that either season or elevated temperature may have an immediate effect on the activity of this enzyme. Individual variability of all three enzymes ranges from 300 to 400%. The activities of pyruvate kinase and D-lactate dehydrogenase are strongly correlated in summer, forming a "constant-proportion-group", whereas in winter, with D-lactate dehydrogenase activity increasing and pyruvate kinase activity decreasing these two enzymes become "uncoupled". The Km value of pyruvate kinase is independent of experimental temperature between 10 and 25 degrees C, whereas that of D-lactate dehydrogenase and arginine kinase increases about three-fold within this range. Thus the temperature relationship of a single enzymic reaction cannot be used as an arguemnt for or against the occurrence of temperature compensation of whole animal metabolism. The possibility of modulation of enzyme activity by environmental temperature is discussed.

Registered nurses' opionions on an extended role concept

Using a Likert-type questionnaire, opinions of 800 professional registered nurses in Texas, selected at random, were surveyed on the extended role concept as reflected by the family nurse clinician (FNC). Thirty percent of the questionnaires were returned and used for data analysis. The survey found that the nurses' years of nursing experience, employment status, field of employment, and education background influenced their opinions on the extent they thought the FNC could assume the defined responsibilities, the areas of the health care delivery system in which the FNC could exert a positive influence, and anticipated problem areas for the practicing FNC. Strongly supportive of the role, the nurses favored the FNC's assuming considerable responsibility in the delivery of primary health care.

Observer agreement in evaluating coronary angiograms

The reliability of interpretation of coronary arteriography as a diagnostic tool was investigated in a sub-study of the VA Cooperative Study of Surgical Treatment for Coronary Arterial Occlusive Disease. Twenty-two physicians with varying levels of experience read 13 cine angiograms -- blind -- on two different occasions. Analysis of inter- and intraobserver variability showed that angiographic items about which observers were most inconsistent from one reading to the other had the largest interobserver disagreement as well. They were the distal portions of the left anterior descending and left circumflex arteries. Among the items on which there was most consistent agreement -- namely, the right main coronary artery and presence of ventricular aneurysm -- there was most often agreement between observers as well. When individual readers were evaluated, some observers were far more consistent in their own readings of all the angiographic items than others. This intraobserver agreement in turn correlated fairly well with how often they agreed with the other observers and with how much experience they reported having in reading coronary cineangiograms.