Absorption of solar radiation by clouds: observations versus models.

There has been a long history of unexplained anomalous absorption of solar radiation by clouds. Collocated satellite and surface measurements of solar radiation at five geographically diverse locations showed significant solar absorption by clouds, resulting in about 25 watts per square meter more global-mean absorption by the cloudy atmosphere than predicted by theoretical models. It has often been suggested that tropospheric aerosols could increase cloud absorption. But these aerosols are temporally and spatially heterogeneous, whereas the observed cloud absorption is remarkably invariant with respect to season and location. Although its physical cause is unknown, enhanced cloud absorption substantially alters our understanding of the atmosphere's energy budget.

Catabolism of very low density lipoproteins in experimental nephrosis.

The effects of experimental nephrosis in rats, produced by puromycin aminonucleoside, include an elevation of plasma levels of all lipoprotein density classes and the appearance of high density lipoprotein (HDL) rich in apoprotein (apo) A-I and deficient in apo A-IV and apo E. The hyperlipoproteinemia is associated with an increase in hepatic synthesis of lipoproteins. The possible role of decreased very low density lipoprotein (VLDL were obtained from nonfasting animals by ultracentrifugation at d 1.006 and included chylomicrons) catabolism and its relationship to the apolipoprotein composition of nephrotic high density lipoproteins (1.063 less than d less than 1.210, or 1.072 less than d less than 1.210 [HDL]) was explored. When 125I-VLDL was injected, the faster plasma clearance of lower molecular weight apolipoprotein B (apo BL) compared with that of higher molecular weight apo BH which is seen in normal rats was not observed in nephrotic rats. Less labeled phospholipid, apo C, and apo E were transferred from VLDL to higher lipoprotein density classes. Heparin-releasable plasma lipoprotein lipase and hepatic lipase activities were decreased by 50% in nephrotic rats compared with pair-fed controls. Perfusion of livers with medium that contained heparin released 50% less lipase activity in nephrotic rats than in controls. When heparin was injected intravenously, significant decreases in plasma levels of triglycerides and significant increases in levels of free fatty acids were observed in both groups of animals. In the nephrotic rats, 86% of the free fatty acids were in the lipoprotein fractions, as compared with 16% in the controls. Heparin treatment did not restore to normal the decreased apo BL clearance in nephrotic rats but it produced an increased amount of apo A-IV and apo E in the plasma HDL. In vitro addition of partially pure lipoprotein lipase to whole serum from nephrotic rats significantly increased the content of apo E in HDL. We conclude that the abnormal apoprotein composition of HDL in experimental nephrosis is the result of altered entry of apolipoproteins from triglyceride-rich lipoproteins, probably because of decreased lipolysis.

Ascites fluid lipoproteins in experimental nephrotic syndrome.

Lipoprotein content and composition were studied in ascites fluid of puromycin aminonucleoside-nephrotic rats. All of the lipoprotein density classes were found in ascites fluid. Protein levels compared to plasma were: very low density lipoprotein (VLDL, d less than 1.006), 1.2%; intermediate density lipoprotein (IDL, 1.006 less than d less than 1.02), 2.6%; low density lipoprotein (LDL, 1.02 less than d less than 1.063), 1.0%; and high density lipoprotein (HDL, 1.063 less than d less than 1.21), 1.1%. The predominant protein in ascites fluid was albumin, present at 1.9% of the plasma level. Radioiodinated VLDL and HDL injected intravenously into nephrotic rats appeared in lipoprotein fractions of the ascites fluid. VLDL and IDL triacylglycerol content and particle diameter were low compared with plasma particles, suggesting peritoneal triacylglycerol lipase activity; such lipase activity could account for the increased proportion of LDL in the ascites fluid. Ascites fluid LDL and HDL phospholipid and free cholesterol were high and cholesteryl ester was low. Ascites lipoproteins contained the same apolipoproteins as plasma, but in different proportions. Ascites VLDL had higher apolipoprotein B and lower apolipoprotein E, while LDL and HDL had higher apolipoprotein E. Ascites HDL could be separated by heparin-Sepharose affinity column chromatography into a retained and a non-retained fraction, while nearly all nephrotic plasma HDL was non-retained. These data suggest that modification of ascites fluid lipoproteins occurs prior to their entry into the lymph and return to the blood, perhaps mediated by peritoneal macrophages.

Saturated fats, cholesterol, and dietary compliance.

BACKGROUND: Lack of response to a cholesterol-lowering diet can be caused by physiological nonresponsiveness, inadequate knowledge, or inability to change dietary habits (poor compliance). The purpose of this study was to evaluate the dietary compliance of hyperlipidemic individuals who received intensive initial dietary education and followup, and who showed an initial reduction of their plasma cholesterol levels. METHODS: One hundred five individuals with fasting cholesterol levels of 5.17 mmol/L (200 mg/dL) or greater received intensive education and follow-up on the American Heart Association Step I diet during an initial 12-week period. The participants provided 3-day dietary records every week, and fasting lipoprotein analysis was performed biweekly. Six months after termination of this period, the subjects were requested to return for a follow-up evaluation of their lipoprotein profile and dietary adherence. RESULTS: Seventy-three (70%) of the subjects returned for a follow-up evaluation of lipoprotein cholesterol levels. Of these, 42 (58%) had a 10% or greater average initial decrease in total cholesterol levels at weeks 3 and 4 ("baseline"), and they were considered to be "high responders." At the 6-month follow up, the average plasma cholesterol level in these responders remained 6.4% below that at entry level, but it had increased by 19% compared with baseline values (6.30 mmol/L [244 mg/dL] vs 5.43 mmol/L [210 mg/dL], respectively). Corresponding significant increases at 6 months were found in high-density lipoprotein cholesterol (8%), low-density lipoprotein cholesterol (16%), and very-low-density lipoprotein cholesterol (66%) levels. Analysis of dietary histories revealed that dietary cholesterol and percent calories from fat increased significantly, but remained within the recommended guidelines. However, the increase in percent calories from saturated fat (from 10.0% +/- 0.5% to 14.4% +/- 1.0% [mean +/- SEM]) deviated markedly from these guidelines. CONCLUSIONS: The results suggest the long-term compliance to the reduction of dietary saturated fat remains a problem, even in individuals who receive intensive initial training and show an early favorable response. Follow-up evaluation of hyperlipidemic patients who are receiving dietary therapy should take into account this behavioral pattern. It remains to be determined whether continuing supervision and better nutritional labeling will facilitate dietary compliance.

Gene transfer into mammalian central nervous system using herpes virus vectors: extended expression of bacterial lacZ in neurons using the neuron-specific enolase promoter.

A herpes simplex virus (HSV) vector in which the mammalian promoter for neuron-specific enolase (NSE) controls expression of a marker gene was analyzed for its ability to drive expression of this foreign gene in culture and in vivo. In cultured cells, the vector appeared to give neuron-specific expression. Introduction of 10(6) pfu of the virus into the adult rat caudate nucleus by stereotactic injection was not toxic to the animals and yielded beta-galactosidase (beta-gal)-positive neurons for at least 30 days after viral inoculation. This recombinant herpes virus vector is the first described to use a mammalian promoter to yield extended expression of a foreign gene product in the adult mammalian central nervous system (CNS).

Comparative efficacy of expression of genes delivered to mouse sensory neurons with herpes virus vectors.

To achieve gene delivery to sensory neurons of the trigeminal ganglion, thymidine kinase-negative (TK-) herpes simplex viruses (HSV) containing the reporter gene lacZ (the gene for E. coli beta-galactosidase) downstream of viral (in vectors RH116 and tkLTRZ1) or mammalian (in vector NSE-lacZ-tk) promoters were inoculated onto mouse cornea and snout. Trigeminal ganglia were removed 4, 14, 30, and 60 days after inoculation with vectors and histochemically processed with 5-bromo-4-chloro-3 indolyl-beta-galactoside (X-Gal). With vector tkLTRZ1, large numbers of labeled neurons were observed in rostromedial and central trigeminal ganglion at 4 days after inoculation. A gradual decline in the number of labeled neurons was observed with this vector at subsequent time points. With vectors RH116 and NSE-lacZ-tk, smaller numbers of labeled neurons were seen at 4 days following inoculation than were observed with vector tkLTRZ1. No labeled neurons could be observed at 14 days after inoculation with vectors RH116 and NSE-lacZ-tk. Immunocytochemistry for E. coli beta-galactosidase and in situ hybridization to HSV latency-associated transcripts revealed labeled neurons in regions of the trigeminal ganglion similar to that observed with X-Gal staining. A comparable distribution of labeled neurons in trigeminal ganglion was also observed after application of the retrograde tracer Fluoro-Gold to mouse cornea and snout. These data provide evidence that retrogradely transported tk- herpes virus vectors can be used to deliver a functional gene to sensory neurons in vivo in an anatomically predictable fashion.

9,11-epoxy-9-homoprosta-5-enoic acid analogues as thromboxane A2 receptor antagonists.

A novel bicyclic prostaglandin analogue, (1S)-[1 alpha, 2 alpha(Z),3 alpha(1E,3S*,4R*),4 alpha]-7-[3-(3-hydroxy-4-phenyl-1-pentenyl)-7- oxabicyclo[2.2.1]hept-2-yl]-5-heptenoic acid (4), was found to be a potent and selective thromboxane A2 (TxA2) receptor antagonist. Alcohol 4 was the only member in a series of allylic alcohols which did not display direct contractile activity in the rat stomach strip model. Alcohol 4 was effective in the inhibition of (a) arachidonic acid induced platelet aggregation of human platelet-rich plasma (I50 = 0.65 +/- 0.1 microM); (b) 11,9-epoxymethano-PGH2 induced contraction of guinea pig trachea (pA2 = 8.0 +/- 0.2) or rat aorta (pA2 = 8.1 +/- 0.2); and (c) arachidonic acid induced bronchoconstriction in the anesthetized guinea pig (1 mg/kg iv). A radioiodinated analogue of 4 bound in a specific and saturable manner to human platelet membranes with a Kd = 2.3 +/- 0.9 nM. Modification of the alpha-chain, in an attempt to minimize in vivo metabolism, resulted in TxA2 receptor antagonists of reduced in vitro potency.

7-Oxabicyclo[2.2.1]heptyl carboxylic acids as thromboxane A2 antagonists: aza omega-chain analogues.

A novel bicyclic prostaglandin analogue, [1S-[1 alpha, 2 alpha (Z), 3 alpha, 4 alpha]]-7-[3-[[[[(1- Oxoheptyl)amino]acetyl]amino]-methyl]-7-oxabicyclo[2.2.1]hept-2- yl]-5-heptenoic acid [-)-7) was found to be a potent and selective thromboxane A2 (TxA2) receptor antagonist. Unlike the related series of omega-chain allylic alcohols, amide 7 and its congeners were uniformly free of direct contractile activity in vitro (bovine coronary) and in vivo (anesthetized guinea pig). Amide 7 was effective in the inhibition of (a) arachidonic acid induced platelet aggregation of human platelet-rich plasma (I50 = 0.18 +/- 0.006 microM), (b) 11,9-epoxymethano-PGH2 induced platelet aggregation of human platelet-rich plasma (I50 = 0.24 microM), (c) 11,9-epoxymethano-PGH2 induced contraction of guinea pig trachea (Kb = 3.0 +/- 0.3 nM) or rat aorta (Kb = 8.8 +/- 1.1 nM), and (d) arachidonic acid induced bronchoconstriction in the anesthetized guinea pig (0.1-1.0 mg/kg iv). Amide 7 inhibited the binding of [5,6-3H2]-[1S- (1 alpha, 2 alpha (Z), 3 alpha, 4 alpha)]-7-[3-[[2-[(Phenyl- amino)carbonyl]hydrazino]methyl]-7-oxabicyclo[2.2.1]hept-2-yl]-5- heptenoic acid to human platelet membranes in a specific and saturable manner with a Kd = 49.6 +/- 1.4 nM.

A simple mathematical model for predicting lithium dose requirement.

Available methods of predicting lithium dose have been based on kinetics of a single test dose. A statistically based mathematical model was developed in which lithium dose is derived by stepwise multiple linear regression based on desired level, form of lithium, concomitant tricyclic use, age, sex, and weight. Predictions of the model were correct to within 300 mg in 66% of the 100 initial cases and within 600 mg in 94% of cases. A validation study of 112 additional cases revealed similar percentage. The simple mathematical expression derived from record review allows the clinician to calculate the relationship of steady-state lithium dosage to serum level prior to initiating treatment.

Prediction of lithium dose: a mathematical alternative to the test-dose method.

A method of estimating the optimal dose of lithium is presented. The charts of 548 patients were reviewed to obtain data regarding the factors thought to affect the lithium dose, and an equation to estimate the dose was derived by stepwise multiple linear regression. The equation was also applied to 390 patients to determine the difference between the estimated and the actual dose; the mean difference was only 19 mg/day and the standard deviation was 325 mg/day. Lithium level, presence of a cyclic antidepressant, age, sex, and weight were found to be important variables for estimation of lithium dose.

Bioavailability of oral and intramuscular molindone hydrochloride in schizophrenic patients.

This study was designed to assess the bioequivalence of intramuscular molindone hydrochloride and marketed oral molindone. Ten schizophrenic patients (mean age, 30.2 years) received oral molindone in single daily doses of 100 or 150 mg for four to eight days followed by intramuscular molindone in single daily doses of 50 or 75 mg for four days. On the last day each molindone formulation was given, plasma samples were collected at baseline and at 0.5, 1, 2, 4, 6, 8, and 12 hours after administration. The pharmacokinetic measures of area under the curve and maximum concentration show that intramuscular molindone is 1.49 to 1.67 times more bioavailable than oral molindone. This finding indicates that once a patient's acute psychotic episode has been stabilized with intramuscular molindone, therapy can continue without interruption by substituting 1.5 mg of oral molindone for every 1 mg of intramuscular molindone. The time to maximum concentration occurred significantly earlier (P = 0.05) with intramuscular molindone (0.6 hours) than with oral molindone (1.1 hours). Elimination half-life values were approximately two hours for both formulations.

Halothane administration during liquid ventilation.

The objective of this study was to test the hypothesis that perfluorochemical (PFC) liquid ventilation (LV) can be used as a vehicle to deliver halothane and induce and maintain analgesia. Seven hamsters were paralysed and stabilized with mechanical gas ventilation, ventilated in alternating cycles with gas and either neat oxygenated PFC liquid or oxygenated PFC liquid mixed with liquid halothane (PFC:hal) 1:50% (volume/vapour); arterial pressure and blood gases were monitored throughout the protocol. After each cycle, the animal was stimulated with a foot clamp for 2 s. Mean arterial pressure (MAP:mmHg) response to this stimulation (percent change from the resting MAP) was used as an index of analgesia. Mean arterial pressure was significantly lower during ventilation with PFC:hal (73 +/- 7 SE) as compared with MAP during neat PFC (113 +/- 5 SE) or gas ventilation (107 +/- SE). Mean arterial pressure response (% change in MAP from baseline) to foot-clamp stimulation was significantly lower with PFC:hal ventilation (+ 12 +/- 5% SE) as compared with neat PFC (+ 28 +/- 8% SE) and gas ventilation (+ 29 +/- 9% SE). There was no statistically significant difference in resting MAP or MAP response to foot-clamp stimulation between cycles of ventilation with neat PFC alone or gas ventilation; arterial blood gases were not significantly different between modes of ventilation or levels of analgesia. The data indicate that halothane can be administered during LV while supporting gas exchange, and demonstrate the feasibility of inducing analgesia while using PFC LV techniques.

Thyroid function and other clinical chemistry parameters in subjects eating iodine-enriched eggs.

Iodine-enriched (IE) eggs are produced by chickens fed a diet containing kelp. These eggs, which contain an average of 711 micrograms iodine/egg, have been reported to reduce plasma cholesterol in humans and laboratory animals. A modified form of these eggs is under consideration for marketing in the United States. 104 hyperlipidaemic subjects were placed on a low-fat diet for 12 wk. Between wk 4 and 12, approximately half of the subjects were randomized to a dietary control group (n = 53) or a group who ingested one IE egg/day in addition to this diet (n = 51). Some subjects in both groups continued in the study for an additional 4-8 wk. No significant adverse clinical effects were observed or reported, with the exception of one subject who reported an allergic-like reaction soon after beginning egg ingestion. All clinical chemistry values remained within normal limits, and comparisons between the egg group and controls were not significant. Three subjects (two in the egg group and one in the control group) had elevated thyroid stimulating hormone levels during the experimental period. All thyroid function tests remained within normal limits in the remaining subjects. Thus, ingestion of one IE egg of the type used in our study appears to be relatively safe and devoid of clinically significant, short-term adverse effects in healthy individuals.

Dentist-monitored bleaching: a discussion of combination and laser bleaching.

The traditional power bleaching and matrix bleaching systems offer many advantages for patients. However, each technique also has some drawbacks. This article recommends a combination approach, which uses the best of both systems. The article also discusses the use of lasers and their possible role in bleaching teeth.

The esthetic dental implant: letting restoration be the guide.

Dental implants originally were placed according to the availability of supportive bone structures. This article describes a new way of approaching implant placement: envisioning the ideal ultimate restoration and developing the treatment plan--and the implant site--to achieve that goal.

Patient maintenance of esthetic restorations.

There are probably as many ways to maintain esthetic restorations as there are restorations. After esthetic treatment is completed, schedule a mandatory postoperative appointment to make certain that whatever technique the patient uses is effective. At the postoperative visit, it should be apparent that the patient's tissue is healthy. If the tissue has not healed, some change in home care or additional periodontal or restorative treatment may be necessary. There are virtually hundreds, perhaps even thousands of home plaque removal devices. The ones mentioned here have worked for us and are therefore discussed. It isn't the type of device that is critical, however, but patient compliance. The described regimens have worked effectively for us in overcoming this obstacle of compliance. Appropriate recall visits with the hygienist should be made at one- to six-month intervals. In the final analysis, your success with esthetic restorations may well depend on your patients' success with esthetic maintenance.

Direct composite veneers versus etched porcelain laminate veneers.

It would appear that over the years, the inherent weakness in composite veneering has been the composite itself. The etched porcelain restoration offers the advantages of increased strength, color, stability, and biocompatibility for a veneering material using composite merely as a luting agent. With the ongoing development of porcelain material, it is possible that the etched porcelain restoration will all but replace direct bonding in most clinical situations.

Anterior esthetic considerations when splinting teeth.

There are many techniques for stabilizing and splinting teeth. No matter which restorative technique is chosen, the technical elements of marginal fit, psychologic contour, cleansibility, and occlusion must be met. When the restoration is in the esthetic zone of the oral cavity, there is an additional element of achieving an acceptable cosmetic result. This article presents an overview of concepts to achieve acceptable esthetic results when teeth are joined together.

The esthetic dental implant: letting restoration be the guide.

Dental implants originally were placed according to the availability of supportive bone structures. This article describes a new way of approaching implant placement: envisioning the ideal ultimate restoration and developing the treatment plan- and the implant site-to achieve that goal.

Restoration-driven implant placement with restoration-generated site development.

In any restoration or natural tooth, the surrounding soft-tissue profile plays an integral role in the final esthetics of a case. Similarly in implant restorations, it is no longer sufficient to merely attach a prosthetic device to the underlying fixture, but for optimal esthetics it has become essential for the implant site to be reconstituted in a three-dimensional approach. This invariably involves redevelopment or replacement of lost hard tissue and redevelopment of the correct soft-tissue profile, so that the implant can be placed in the desired position as determined by the restoration, while the soft-tissue profiles are in turn generated by the actual form and contours of the prosthetic device. This article addresses an approach to implant site development.