Ultrastructural studies on a chlorella virus from Germany

This is the first report on the morphology and fine structure of chlorella virus Göttingen-1 (CVG-1), an European member of the newly approved family Phycodnaviridae, which infects certain unicellular, eukaryotic, exsymbiotic, green algae. CVG-1 are polyhedral particles 145-160 nm in diameter. The capsid consists of two shells, apparently composed of ca. 7 nm subunits. Whereas the outer shell of the capsid appears to be icosahedral, the inner shell appears to be irregular underneath one vertex of the virion. In this vertex the inner shell is separated from the outer shell leaving a distinct space ("empty vertex") of unknown function.

Topical timolol administration reduces the incidence of glaucomatous damage in ocular hypertensive individuals. A randomized, double-masked, long-term clinical trial (1)

OBJECTIVES

A randomized, double-masked, 5-year clinical trial was conducted to determine whether topical timolol therapy was more effective than placebo in delaying or preventing the onset of glaucomatous damage in moderate-risk ocular hypertensive subjects.

METHODS

One eye was chosen randomly to receive timolol therapy twice daily; the fellow eye received placebo (timolol vehicle). The primary end point of the study was reproducible visual field loss detected on three consecutive tests. Automated static threshold visual fields were added to the protocol as the study proceeded, and criteria for reproducible defects for the automated fields were developed. The secondary end point was progressive optic disc cupping confirmed by examination of stereoscopic disc photographs. Intraocular pressure was not used as an end point (i.e., eyes were not withdrawn from the study because they reached a predetermined level of intraocular pressure).

Prediction of immediate ventricular arrhythmias after coronary artery ligation

OBJECTIVES

Our aim was to test the hypothesis that increased beat to beat morphologic variations in the body surface electrocardiogram (ECG) are associated with fragmented diastolic electrical activity that appears after coronary artery ligation and to correlate the appearance of spontaneous ventricular fibrillation after coronary ligation with the magnitude of the ECG beat to beat variability.

BACKGROUND

Unstable and variably delayed electrical activation precedes the development of ventricular fibrillation in dogs with acute ischemia. Detection of these highly variable low amplitude signals from the body surface is currently impossible. We have developed a system designed to measure the degree of beat to beat variability of the ECG.

METHODS

With high fidelity electrocardiography, subtle beat to beat ECG morphologic variations were detected in epicardial and body surface electrograms and quantified as the variance of the ECG voltage at specific points of the cardiac cycle. The ratio of the variance at the QRS offset to that of the QRS onset (beat to beat variability index) was then calculated.

RESULTS

Ventricular fibrillation developed in 12 of 27 dogs after left anterior descending coronary artery ligation. In 7 of the 12 dogs it occurred immediately (< 15 min) after ligation; in the other 5 it developed late (> 15 min) after ligation. Dogs with subsequently immediate ventricular fibrillation had a significantly higher beat to beat variability index than that of dogs with late or no ventricular fibrillation both before coronary ligation (4.7 +/- 1.4 vs. 1.1 +/- 0.2 and 0.8 +/- 0.1, respectively, p < 0.001) and after ligation (6.4 +/- 2.6, 1.0 +/- 0.6 and 1.2 +/- 0.6, respectively, p < 0.001). In dogs that developed ventricular fibrillation immediately after coronary ligation, the arrhythmia was preceded by fragmented diastolic electrical activity on the epicardial electrogram and a simultaneous increase in the beat to beat morphologic variability of the terminal portion of the body surface ECG QRS complex.

CONCLUSIONS

Beat to beat QRS offset morphologic variations appear to be increased before and further increased after coronary artery ligation in dogs that develop ventricular fibrillation immediately after ligation. Increased beat to beat variability index may be associated with the presence of electrophysiologic instability and can predict early ventricular fibrillation.

Psoriasis and human immunodeficiency virus infection

BACKGROUND

Psoriasis associated with human immunodeficiency virus (HIV) infection has been reported to be severe and perhaps associated with decreased survival.

OBJECTIVE

Our purpose was to document the natural history, response to therapy, and effect of psoriasis and its treatment on survival in HIV-infected patients with psoriasis.

METHODS

This was an observational cohort study of 50 persons with psoriasis and HIV infection followed up during a 2-year period.

RESULTS

In one third of the patients the psoriasis appeared before 1978, the year when HIV seroconversion began in San Francisco (group I). In two thirds psoriasis developed after 1978 (group II). Group I had a lower mean age of onset (19 vs 36 years) and more commonly had a family history of psoriasis. Palmoplantar and inverse psoriasis were more common in group II. Severe psoriasis occurred in one fourth of this group (12 of 50 patients). The median survival in this group after diagnosis of acquired immunodeficiency syndrome (AIDS) was 19 months, which is comparable to the median survival for all AIDS patients diagnosed in San Francisco between 1984 and 1990.

CONCLUSION

Psoriasis in the setting of HIV disease may be mild, moderate, or severe. Standard therapies and zidovudine are effective in management. Survival does not seem to be adversely affected by the presence of psoriasis or its therapy.

Transient ST segment depression during Holter monitoring: how to avoid false positive findings

To increase the specificity of 24-hour Holter monitoring in detecting transient myocardial ischemia, we separated genuine ST deviations from those dependent on artifacts by adding a detailed shape analysis of real-time printouts to the usual criteria of significant ST segment depression. We screened 116 apparently healthy subjects; 31 had to be excluded, because of pathologic findings in preliminary examinations. The remaining 85 (49 women and 36 men; mean age, 43.1 years) underwent Holter monitoring for assessment of the extent, frequency, and duration of episodes of horizontal and descending ST segment depression of at least 0.1 mV that persisted for at least 60 msec after the J point and that were at least 1 minute apart. On the basis of these criteria, six subjects (7.1%) showed 24 episodes of horizontal or descending ST segment depression with a mean of 0.2 mV (range, 0.15 to 0.25 mV), a frequency of four episodes per 24 hours (one to nine), and a duration of 12.2 minutes (range 3-range 41 minutes). Supplementary criteria--e.g., sudden onset of ST segment depression, identical orientation of PQ and ST segments, or simultaneous increase in R and P wave amplitude--made it possible to identify ST changes caused by artifacts in four volunteers. In only two subjects (2.4%) could true silent ischemia not be differentiated from false positive results. Thus consideration of only the extent, frequency, and duration of episodes does not permit a differentiation between true silent ischemia and false positive results. A supplementary shape analysis increases the specificity of ST segment analysis in detecting transient myocardial ischemia during 24-hour Holter monitoring.

Hypothyroidism in adults with sickle cell anemia

Persons with sickle cell anemia have several indications for transfusion of red blood cells. One of the complications of transfusion of red blood cells is iron overload. Iron overload has been associated with multiple endocrine abnormalities. We report herein three cases of hypothyroidism in adult individuals with sickle cell disease. All three patients were over the age of 45 years at the time of the diagnosis and had received multiple units of transfused red blood cells and had serum ferritin levels of greater than 6,000 ng/mL. All patients were diagnosed during times when they were critically ill. Replacement therapy was instituted in all cases; however, all three patients died shortly after the diagnosis of hypothyroidism was made. Congestive heart failure appeared to be a primary cause of death in all three patients. In the one patient in whom a postmortem examination was done, there was evident extensive fibrosis of the thyroid gland as well as extensive deposition of iron in the cells lining the thyroid follicles. We believe that this represents the first report of clinical hypothyroidism in patients with sickle cell anemia who have received multiple transfusions. Awareness of this condition is especially important given that congestive heart failure is common in sickle cell disease.

Beat-to-beat electrocardiographic morphology variation in healed myocardial infarction

Using high-fidelity electrocardiographic (ECG) amplifiers, we measured subtle beat-to-beat ECG morphologic variations at different phases of the ECG complex. The electrocardiograms were recorded from 49 men with a documented Q-wave myocardial infarction and from 30 age-matched normal men. Forty consecutive beats were averaged to achieve an average ECG signal from which variance could be calculated. The relative variance, defined as the ratio between the integrated variance of the examined window and the integrated variance of the ECG signal that was close to full cycle length, was calculated at QRS onset and at offset in 2 frequency bands (4 to 40 and 60 to 120 Hz). Patients with healed infarction had a relative variance of 2.1 +/- 0.5 (mean +/- standard deviation [SD]) at QRS offset (a window of 40 ms), which was significantly lower than that of the healthy volunteers: 2.5 +/- 0.33 (mean +/- SD; p less than 0.02) at the low-frequency band. At the high-frequency band, patients with healed infarction had a significantly higher relative variance than the control subjects at QRS onset: 1.95 +/- 0.58 vs 1.55 +/- 0.35 (mean +/- SD; p less than 0.005). A model based on the numerous minor conduction abnormalities that exist in the chronically ischemic myocardium is presented to explain the changes in variance at the onset and offset of the QRS. The variance changes described can eventually serve as quantitative indexes of myocardial injury and electrical stability in patients with ischemic heart disease.

Cloning and sequencing of rat plectin indicates a 466-kD polypeptide chain with a three-domain structure based on a central alpha-helical coiled coil

We have determined the complete cDNA sequence of rat plectin from a number of well-characterized overlapping lambda gt11 clones. The 4,140-residue predicted amino acid sequence (466,481 D) is consistent with a three-domain structural model in which a long central rod domain, having mainly an alpha-helical coiled coil conformation, is flanked by globular NH2- and COOH-terminal domains. The plectin sequence has a number of repeating motifs. The rod domain has five subregions approximately 200-residues long in which there is a strong repeat in the charged amino acids at 10.4 residues that may be involved in association between plectin molecules. The globular COOH-terminal domain has a prominent six-fold tandem repeat, with each repeat having a strongly conserved central region based on nine tandem repeats of a 19-residue motif. The plectin sequence has several marked similarities to that of desmoplakin (Green, K. J., D. A. D. Parry, P. M. Steinert, M. L. A. Virata, R. M. Wagner, B. D. Angst, and L.A. Nilles. 1990. J. Biol. Chem. 265:2,603-2,612), which has a shorter coiled-coil rod domain with a similar 10.4 residue charge periodicity and a COOH-terminal globular domain with three tandem repeats homologous to the six found in plectin. The plectin sequence also has homologies to that of the bullous pemphigoid antigen. Northern blot analysis indicated that there is a significant degree of conservation of plectin genes between rat, human, and chicken and that, as shown previously at the protein level, plectin has a wide tissue distribution. There appeared to be a single rat plectin gene that gave rise to a 15-kb message. Expression of polypeptides encoded by defined fragments of plectin cDNA in E. coli has also been used to localize the epitopes of a range of monoclonal and serum antibodies. This enabled us to tentatively map a sequence involved in plectin-vimentin and plectin-lamin B interactions to a restricted region of the rod domain.

[Osteosynthesis of the clavicle. Indications, surgical technique, results]

The osteosynthesis of the clavicle should be the exception and should only be indicated in the case of complicated fractures. The high rate of pseudoarthrosis given in medical literature, is due to errors in indication, selection of implants and in surgical techniques. Procedures like intramedullar wiring, axial screwing and single cerclage-wire suture are unsuited for osteosynthesis of the clavicle. After osteosynthesis of the clavicle we have found exceptional positive results, with respect to functional, radiological and after subjective evaluation, at a low rate of complication without any consequences occurring in the years to come. These results show, that mainly good or even excellent success can be achieved, at a limited indication, combined with careful surgery and a standardized surgery procedure of osteosynthesis of the clavicle.

Centers of rotation with transverse forces: an experimental study

A new noninvasive method for simultaneously applying a known force system and measuring tooth movement was developed and tested. The instruments proved to be highly accurate and reliable. Using a model of an upper canine with a simulated periodontal ligament, we located the center of rotation and the center of resistance and found that the product of two distances--a, from the center of resistance to the line of application of force (F) and, b, from the center of resistance to the center of rotation (Co)--yields a constant that represents the parallel transverse forces in the same plane. Knowing this constant enables the clinician to determine the appropriate force position for a given center of rotation. We also found that the occlusoapical position of the center of resistance varies somewhat, depending on the transverse direction of loading around the long axis. Differences in values of the constant were found also to depend on the direction of loading in a given plane. Thus a transverse force exerted in a mesiodistal direction at the level of an orthodontic bracket through the long axis produces different effects from those produced when an identical force is applied in a labiolingual direction.

Scale formation in algae

Scale biogenesis in algae represents a unique model system to study the transport of secretory macromolecules through the Golgi apparatus (GA) and their exocytosis. The larger scales can be visualized in the light microscope, and thus the kinetics of scale assembly, transport, and secretion can be studied in vivo. In addition, scales are osmiophilic and readily visible in conventional transmission electron microscopy; thus, details of scale assembly and sorting can be studied without invoking immunolabeling techniques. The following are distinctive features of scale biogenesis in algae: 1) transport of scales through the GA-stack occurs by cisternal progression; 2) scale secretion may be very rapid (in some cases a single GA-cisterna leaves the stack every 15-20 s); 3) sorting of different scale types does not occur in the GA, but in a post-GA-compartment. Recent progress in the analysis of scale formation in the green flagellates Tetraselmis and Scherffelia is reviewed.

Topical 8-bromo-cyclic GMP lowers intraocular pressure in rabbits

The topical application of 8-bromo-3'-5'-cyclic guanosine monophosphate (8BrcGMP) produces significant decreases in intraocular pressure (IOP) in rabbit eyes. Maximum effects are obtained with a 4% concentration, and IOP is reduced significantly (P less than 0.001) between 30 and 240 min after administration of the agent. The decrease in IOP occurs without significant change in tonographic outflow facility. A significant further decrease in IOP can be induced by topical 8BrcGMP in rabbits whose IOP has been lowered by the systemic administration of the carbonic anhydrase inhibitor acetazolamide.

[A new method for determination of nicotinic acid in plasma]

A new and sensitive method for the detection of nicotinic acid in plasma is described. Human or rat plasma-samples from pharmacological or pharmacokinetic studies are lyophilized and extracted with methanol. After removal of the solvent the residue is converted with N-Methyl-N-trimethylsilyltrifluoracetamide to the trimethylsilylester of nicotinic acid, separated by vpc and detected with a mass selective detector via the fragment 180 amu. 6-Methyl-nicotinic acid is used as internal standard (fragment 194 amu). With this method a detection limit of 100 ng/ml plasma is reached.

Neurologic, computed cranial tomographic, and magnetic resonance imaging abnormalities in patients with small-cell lung cancer: further follow-up of 6- to 13-year survivors

To determine the subsequent evolution of neurologic, neuropsychologic, and intracranial anatomic findings in long-term survivors of small-cell cancer, we repeated an evaluation done 4 years previously in patients 6 to 13 years after treatment. Fifteen patients were reevaluated with a history and physical examination, mental status examination, neuropsychologic testing, computed cranial tomographic (CCT) scans, and magnetic resonance imaging (MRI). All but one was ambulatory and none were institutionalized. Thirteen of 15 had neurologic complaints, 10 of 15 had an abnormal neurologic examination, seven of 14 had an abnormal mental status examination, 12 of 14 had abnormal neuropsychologic testing, 12 of 15 had abnormal CCT scans, and seven of 15 had white-matter abnormalities on MRI scans. No dramatic decline in performance status, functional status, neurologic symptoms, or neurologic examination occurred in these patients with 4 years of additional follow-up. More patients showed a decline in mental status examinations and neuropsychologic testing than demonstrated improvement. Anatomic studies showed no dramatic changes in the CCT scans and MRI confirmed these findings. From these data we conclude that there is a slow decline in neuropsychologic function in some of the patients surviving more than 6 years from a diagnosis of small-cell lung cancer. The anatomic abnormalities documented by CCT scans and MRI are more frequent in patients with abnormal neuropsychologic function.

Topical timolol administration reduces the incidence of glaucomatous damage in ocular hypertensive individuals. A randomized, double-masked, long-term clinical trial

We conducted a randomized, double-masked, long-term clinical trial to determine whether topical timolol therapy was effective in delaying or preventing the onset of glaucomatous damage in moderate-risk ocular hypertensive subjects. In 62 patients, one eye was chosen randomly to receive timolol therapy twice daily while the fellow eye received placebo. During the course of the study, the mean +/- SD difference in intraocular pressure between the timolol-treated and the placebo-treated eyes was 2.3 +/- 2.6 mm Hg. Reproducible visual field loss developed in 4 timolol-treated eyes and 10 placebo-treated eyes. Progressive optic disc cupping was noted in 4 timolol-treated and 8 placebo-treated eyes. Using a computerized image analysis system, the mean +/- SD increase in optic disc pallor during the course of the study was 0.86% +/- 2.4% in the timolol-treated eyes as opposed to 1.80% +/- 3.6% in the placebo-treated eyes. This study provides evidence that lowering intraocular pressure by medical treatment reduces the incidence of glaucomatous damage in ocular-hypertensive individuals.

Atrial natriuretic peptides. Effects on intraocular pressure, cGMP, and aqueous flow

We report a significant decrease in intraocular pressure after intravitreal injection of atrial natriuretic peptide (AP). There is also an increase in cGMP in iris-ciliary body preparations after exposure to physiologic concentrations of AP in vitro. We present evidence that after intravitreal AP administration there is a decrease in aqueous humor flow associated with the decrease in intraocular pressure. The changes in aqueous humor flow were estimated by automated fluorophotometry and aqueous humor ascorbate concentrations.

Identification of 3-deoxy-manno-2-octulosonic acid, 3-deoxy-5-O-methyl-manno-2-octulosonic acid and 3-deoxy-lyxo-2-heptulosaric acid in the cell wall (theca) of the green alga Tetraselmis striata Butcher (Prasinophyceae)

The main constituent of the cell wall complex carbohydrate of the scaly green alga Tetraselmis striata Butcher is shown to be 3-deoxy-manno-2-octulosonic acid (42%). In addition two other 2-keto-sugar acids are present, namely, 3-deoxy-5-O-methyl-manno-2-octulosonic acid (7%), the first methylated derivative of 3-deoxy-manno-2-octulosonic acid found in nature, and 3-deoxy-lyxo-2-heptulosaric acid (11%). The characterization of the three 2-keto-sugar acids has been carried out on the corresponding methyl ester methyl glycosides using GLC-MS and 500-MHz 1H-NMR spectroscopy, and on the corresponding reduced alditol acetates using GLC-MS. Other monosaccharides occurring in the cell wall are D-galacturonic acid (14%), D-galactose (4%), D-gulose (2%), D-glucose (1%) and L-arabinose (1%).

Breakdown of the blood--aqueous barrier in the rabbit eye by infrared radiation

Breakdown of the blood-aqueous barrier was produced by infrared radiation (IR) at a heat flux from 24 to 44 J/cm2 in pigmented, but not in albino rabbits. Blood-aqueous barrier breakdown was inhibited by indomethacin and ketamine/xylazine anesthesia mixtures, but not by [D-Trp2,D-Pro7,9]-substance P. The degree of blood-aqueous barrier breakdown could be controlled by IR flux. Two models for accurate determination of the heat flux are presented.