Ionic channels of Paramecium: from genetics and electrophysiology to biochemistry

This paper reviews the combined genetical, electrophysiological and biochemical analysis of excitation that has been carried out in Paramecium. Paramecium cells display graded Ca++ action potentials in response to a variety of stimuli. These action potentials regulate the orientation of the ciliary beat hence the cell's swimming behaviour. A large array of mutants displaying altered behaviour have been isolated and mapped to over 20 loci. Detailed electrophysiological analyses have been carried out on several classes of mutants revealing defects in specific ion channels in some cases. Mutants have proven very useful to analyze channel properties, to unravel interactions between channels and to discover the function of these channels in a variety of cellular processes. Some important channels are located in the ciliary membranes and cilia as well as ciliary membranes can now be purified in high purity and reasonable yield. These fractions have been used recently in a variety of biochemical approaches to gain insight into the molecular components of the excitation machinery. Specific alterations in some minor membrane proteins have been found in two mutants as well as a specific defect in sphingolipids in a third mutant. Those alterations had to be distinguished from large scale variations in membrane proteins and lipids that occur in this organism in response to modifications in growth conditions. Several other recent biochemical developments are reviewed and the advantages as well as the difficulties of the genetic approach to the molecular study of biological processes are discussed.

Reduced vascular trauma after temporary occlusion with modified Biemer and Yasargil clips

The Biemer and Yasargil microvascular clips that are currently available commercially can traumatize the vascular endothelium. In an effort to resolve this problem, both clip designs were structurally modified by changing the length, width, and surface of the clip blades in various ways. Also, the occlusion force of the clips was set at either 15 or 30 g. Studies on the carotid arteries of 140 rats showed a correlation between the structural and mechanical alterations of the clips and the degree of endothelial trauma produced by temporary occlusion for 1 hour. The most favorable results were obtained with a Biemer clip that had long, wide, smooth blades and an occluding force of 15 g.

The controlled delivery of thiopental and delayed cerebral revascularization

Sodium thiopental was administered to 10 dogs following embolization of the middle cerebral artery. Its effect on the "grace period" for revascularization was investigated by performing embolectomies 6 hours later. We observed a striking reduction in the size of infarction in the animals treated with thiopental at moderate and prolonged dosage levels. The control animals treated with pentobarbital received less protection against ischemia although blood levels were similar to those of the experimental groups during the period of vascular occlusion.

Scanning electron microscopic and X-ray energy spectrographic analysis of the inner surface of human atherosclerotic carotid plaques

Forty specimens of carotid plaque from 30 patients who had suffered cerebrovascular accidents and 10 asymptomatic control patients were examined by light and scanning electron microscopy (SEM). The SEM revealed the finely detailed surface characteristics of the plaque including cell deposits, endothelial damage, and exposed subendothelium. X-ray energy spectrography scans revealed that 7 specimens had calcium deposits. Presurgical treatment with dipyridamole and aspirin inhibited or substantially reduced thrombus formation.

Reye's syndrome in three siblings. Association with type A influenza infection

Reye's syndrome occurred simultaneously in three siblings. All had characteristic changes in liver histology ascertained by light and electron microscopy. The two patients with the most severe disease also had serum that caused marked stimulation of mitochondrial state 4 respiration in vitro. Histocompatibility locus antigen typing showed that no unique haplotypes were shared by all three children. There was no evidence of exposure to aflatoxins, pesticides, or other substances that have been previously postulated to be associated with Reye's syndrome. Influenza A/Brazil/11/78-like virus was isolated from one patient, and all three patients had a fourfold or greater rise in hemagglutination-inhibiting antibody to H1N1 influenza virus.

Visually monitored postrotary nystagmus in seven autistic children

Therapists who evaluate the sensorimotor functions of autistic children have become increasingly interested in monitoring their responses to vestibular stimulation. In this study, the duration of the nystagmus reflex is visually monitored and then measured by means of a stop-watch. Each of 7 autistic subjects received 18 sessions (36 trials) of horizontal semicircular canal stimulation during a period of 25 days. In each trial a graduated acceleration in a hand operated rotating chair preceded an abrupt stop, with a rapid deceleration from 180 degrees/second to 0 degree/second. Although subject option (intentional response) imposes limitations on the data interpretation, inspection of the nystagmus functions over time suggests the following: substantial trial-to-trial variability; substantial subject-to-subject variability; greater scores following trials to the subjects' left (the direction of the second trial in each session) than to the right (the direction of the first); and no evidence of consistent change for most subjects in nystagmus duration across the 36 trials. Implications for clinical evaluation of nystagmus are discussed.

Segregation of rapidly acetylated histones into a chromatin fraction released from intact nuclei by the action of micrococcal nuclease

It has been previously shown that micrococcal nuclease digestion and subsequent fractionation of hen oviduct nuclei generates fractions enriched (first supernatant fraction - 1SF) and depleted (second supernatant fraction - 2SF) in ovalbumin genes, while a third fraction, the pellet fraction, contains about the same level of this gene as whole chromatin (Bloom and Anderson (1978) Cell 15, 141-150). We have utilized this fractionation method in an attempt to assess the extent and kinetics of histone acetylation associated with chromatin from the 1SF, 2SF, and pellet fraction. Hepatoma Tissue Culture (HTC) cells were labelled for 30 minutes in vivo with 3H-acetate, nuclei isolated and the chromatin fractionated. The specific activity of the histones in the 1SF was slightly greater than that of the 2SF (1.2 to 1.6 fold difference) independent of the length of nuclease digestion. If the labelling period is followed by short (10 to 60 minute) treatment of the cells with sodium butyrate, the more rapidly as well as more extensively acetylated histones are also preferentially found in the 1SF. This is in part the result of segregation of chromatin particles into the 1SF as the histones associated with these particles become hyperacetylated. That is, the extent of histone acetylation regulates the distribution of chromatin in the 1SF, 2SF and pellet fraction.

Abnormal whole-body and cellular (erythrocytes) turnover of 22Na+ in normotensive relatives of probands with established essential hypertension

1. Whole-body elimination rate of 22Na+ was decreased in normotensive or borderline first-degree relatives of hypertensive probands. 2. Whole-body potassium, exchangeable sodium and urine excretion of sodium, potassium and creatinine were similar in relatives and controls. 3. Erythrocyte net influx of 22Na+ was significantly increased in normotensive relatives. 4. Abnormal whole-body and cellular handling of sodium (22Na+) demonstrated in relatives indicates that this abnormality may have an important role in the development of essential hypertension in man.

Minimum vascular occlusive force

A mathematical analysis of the minimum occlusion force necessary to occlude small vessels based on the parametric influence of blood pressure, vessel diameter, clamp width, and vessel shape after clamping was performed. The results were confirmed by in vivo experimentation with 60 rat aortas (of 1.8 to 2.4 mm caliber) using a variable-force clamp gauge developed in our laboratory. Experimental and theoretical results differed by only 3 gm. Scanning electron microscopy revealed that the initial changes in the endothelium occurred in smaller radii of curvature. Increased pressure resulted in gross morphological changes across the vessel. The minimum occlusion force (as determined by the variable-force clamp gauge) produced only minimal endothelial damage.

Cardenolide analogues: 10--characterization of cardiac glycosides by chemical ionization mass spectrometry

The potential of chemical ionization mass spectrometry for the characterization of naturally occurring and semi-synthetic cardiac glycosides has been investigated. Methane, isobutane and ammonia were used as reactant gases. With the exception of ouabain, the ammonia chemical ionization mass spectra of the cardiac glycosides examined in this work contained abundant [M + NH4]+ions and abundant fragment ions formed by cleavage of glycoside bonds. Ammonia chemical ionization mass spectrometry was found to provide a rapid and sensitive method for the characterization of the products of glycosidation reactions. In contrast, the methane and isobutane chemical ionization mass spectra of the cardiac glycosides, with the exception of ouabain, did not contain protonated molecular ions and did not contain abundant fragment ions above m/z 400.

Laboratory-based surveillance of influenza virus in the United States during the winter of 1977-1978. I. Periods of prevalence of H1N1 and H3N2 influenza A strains, their relative rates of isolation in different age groups, and detection of antigenic variants

Influenza A (H3N2) viruses were isolated from outbreaks and epidemics of disease during the period December 1977 to March 1978. For the last two months of this period, H1N1 strains of influenza A were also responsible for epidemics. In some regions (e.g., Hawaii) co-circulation of H1N1 AND H3N2 strains occurred, whereas in other regions (e.g., Wisconsin) isolation of H3N2 strains had almost ceased prior to isolation of H1N1 strains. Few influenza B isolates were reported. Analysis of the ages of patients from whom specimens were submitted for influenza virus isolation confirmed that, whereas H3N2 strains were isolated from persons of all ages, greater than 97 per cent of H1N1 isolates in six states analyzed were recovered from patients less than 26 years old, although specimens were tested from older persons who were ill during the period of prevalence of H1N1 influenza. The majority of H3N2 isolates tested by hemagglutinin-inhibition reaction were similar to A/Texas/1/77, and the majority of H1N1 isolates were similar to A/USSR/90/77. Antigenic analysis of isolates, however, identified a small number of variants of H3N2 and H1N1 strains.

Non-polio enterovirus activity in Wisconsin based on a 20-year experience in a diagnostic virology laboratory

Laboratory test results, demographic information, and clinical data on 1364 patients who had specimens submitted to the Wisconsin State Laboratory of Hygiene and from whom non-polio enteroviruses were isolated during 1957--1976 were examined. Echoviruses (echo) and Coxsackievirus group B (CB) and group A (CA) were isolated from 719, 389, and 256 of the patients, respectively. Thirty-five different serotypes were identified in the 20-year period. The six most frequently occurring serotypes (echo 9, CB 5, echo 18, CB 2, CB 4, and echo 6) were associated with 57 per cent of all illnesses. The first three serotypes occurred in an epidemic-like manner whereas the next three appeared to be endemic. Eighty-eight per cent of all isolations were from patients whose illnesses began in July through October. The percentage of CA isolates obtained from adults was much smaller than the corresponding percentages seen with CB or echo. A majority of the non-polio enteroviruses were obtained from males. Central nervous system and gastrointestinal tract involvement was greatest with echo and CB 5 tract and lowest with CA and CB 1--4 illnesses. The highest frequency of respiratory tract involvement was with CA and echo 9 illnesses and rash was most frequent with CA illnesses. The highest frequency of hospitalization was with CB 5 patients.

Histone deacetylation in nuclei isolated from hepatoma tissue culture cells. Inhibition by sodium butyrate

Nuclei from hepatoma tissue culture (HTC) cells were isolated by standard methods and incubated in media commonly used for nuclease digestions (DNAase I and micrococcal nuclease) and for in vitro RNA synthesis. During the incubation, histones can be deacetylated from both control cells and cells treated with 6 mM sodium butyrate to enhance the levels of histone acetylation. Deacetylation of histone is much more apparent in nuclei isolated from sodium butyrate-treated cells. Inclusion of 6 mM sodium butyrate in the incubation medium effectively inhibits the endogenous deacetylase activity acting on histones H3 and H4, whereas sodium acetate at the same concentration has very little inhibitory effect.

A correlation between nucleosome spacer region susceptibility to DNase I and histone acetylation

Hepatoma tissue culture (HTC) cell nuclei were digested with either DNase I or micrococcal nuclease and the nucleohistone digestion products fractionated by gel electrophoresis or exclusion chromatography. Under appropriate conditions, gel electrophoresis demonstrates that for both nucleases, only cleavages within the nucleosome spacer regions and not within the nucleosome core lead to freely migrating nucleohistone particles. These particles consist of nucleosome cores, nucleosomes and nucleosome oligomers. Following DNase I digestion and fractionation by exclusion chromatography, analysis of the histones indicates a direct relationship between increased spacer region susceptibility to nuclease and increased nucleosomal histone acetylation. Evidently digestion sites outside the regions of DNA protected by core histones can reflect the degree of acetylation of core histones. Such a relationship is not found when micrococcal nuclease is used to digest the samples.

Pentothal protection for delay cerebral revascularization

Thiopentone (20 mg/kg/bolus and 20 mg/kg/three hours) was effective in preventing infarction in five dogs with six hours of middle cerebral occlusion. Nine control animals sustained massive to large infarctions. Utilizing this regime therapeutic blood levels were rapidly attained for over 12 hours without side effects. From the experimental and human experience with focal cerebral ischaemia, there appears to be a finite grace period in which cerebral revascularization can be undertaken. In canine and primate models this time has been about five hours, following which the infarction process may not be reversible (Sundt et al. 1977, Laha et al. 1978). Seeking to prolong this grace period, thiopentone was selected as an ideal drug for this purpose, and its effect on the revascularized canine middle cerebral distribution was evaluated at six hours following embolectomy.

Nephrotic Syndrome (NS): Evidence for Increased Platelet Prostaglandin Synthesis

NS is associated with an increased incidence of arterial and venous thrombosis. Hemostasia was evaluated in 11 children with NS (6 with active disease Grp I, and 5 in remission Grp II). Studies included assays for fibrinogen, FDP, Antithrombin III (AT III), platelet count and aggregations. Platelet malonyldialdehyde (MDA) in the presence of N-ethyl maleimlde (NEM) or thrombin was used as an indicator of endoperoxide formation, and platelet survivals were performed in 3/11. Platelet hyperaggregability was present in Grp I and was associated with significantly increased platelet MDA in the presence of both NEM (4.0 ± 0.29), or thrombin (1.77 ± 0.32) compared to normal controls (3.20 ± 0.26; 1.26 ± 0.18). Other evidence for a “hypercoagulable” state included a marked reduction in plasma AT III levels to 9.4 ± 3.8 (controls 24 ± 3 mg/100 ml), and a reduction in platelet life-span in both children in Grp I in whom this study was performed (T½ of 2.1 and 2.5 days). Grp II patients did not demonstrate platelet hyperaggregability and platelet MM was normal (3.21 ± 0.4; 1.13 ± 0.19). AT III levels were normal at 26.5 ± 4.8 mg/100 ml, and platelet life-span was normal in 2/2 children (T½ of 3.6 and 4.4 days). The normal half-life of 4.4 days was obtained in the same child in whom a T½ of 2.5 days was present during active disease. Since a reduction in platelet survival is associated with an increased risk of thromboembolism in a number of pathological states, this finding is of clinical significance and may identify the patient with NS who is at risk. Platelet hyperaggregability in this syndrome is prostaglandin related, and appears to be due to an increase in platelet endoperoxide formation.

Performance of psychiatric inpatients on three standard tests of intelligence

The Quick Test, Peabody Picture Vocabulary Test, and the Wechsler Adult Intelligence Scale were administered to 40 psychiatric inpatients. High correlations and minimal mean differences obtain among measures.

Transillumination detection of a growing skull fracture

Transillumination is shown to be an effective device in the early diagnosis of enlarging skull fractures in children.

Epinephrine-induced cystoid macular edema in aphakic eyes

A population of glaucomatous aphakic eyes being treated with topical epinephrine compounds was studied in order to determine the incidence of cystoid macular edema that had been induced by this medication. Eyes were considered responders only if fluorescein angiography demonstrated that macular edema was eliminated with discontinuation of epinephrine and recurred with reapplication of epinephrine. Reversible maculopathy occurred in six of 47 eyes. Topical epinephrine caused macular edema in an appreciable percentage of aphakic eyes, and we recommend that other medications be used to control glaucoma in aphakic patients when possible. If epinephrine compounds are required, periodic angiography is advisable.

Free-living volunteer's motivations and attitudes toward pharmacologic studies in man

Two groups of volunteers who had participated in pharmacologic studies were interviewed about their impressions of such studies. One group was from a university community, the other from the pharmaceutical industry. The differences between the two groups were correlated with their respective backgrounds. Both groups had favorable impressions about drug studies and investigators. Most were satisfied with the information given them about the nature and risks of the studies, but some believed that a written description of the study that they could consult at home would improve their understanding of the information. Financial reward was the primary reason given by both groups for volunteering, but the perceived risk of the study was the ultimate deciding factor. The volunteers disliked having their mobility restricted and for this reason might not be willing to participate in long-term studies, such as those formerly carried out in prisons. Alternative sources of volunteers for long-term studies will have to be found.

Fine structure and origin of amyloid deposits in pituitary adenoma

A pituitary adenoma with amyloid deposits was studied by light and electron microscopy. The amyloid material was radially oriented, deposited in the extracellular space, and often intermingled with small vesicles. It was surrounded by histiocytes with deep cytoplasmic invaginations. The histiocytes contained large autophagic vacuoles in which amyloid was also present. These features are similar to other forms of amyloidosis and suggest a histiocytic origin of the amyloid.