Central nervous system antigen (NS-5) and its presence during murine ontogenesis.

An antiserum raised by immunization of C3H.SW/Sn mice with cerebellum from 4-day-old C57BL/6J mice recognizes a cell surface component(s) [NS-5] present in different degrees on various parts of the mouse central nervous system. When analyzed by an antiserum- and complement-mediated cell cytotoxicity test and by the ability of various tissuesto absorb anti-NS-5 antiserum activity, the antigen(s) was detectable on cerebellum, retina, olfactory bulb, cortex, basal ganglia, and medulla but not on nonneural tissues with the exception of mature spermatozoa and 4-day-old kidney. The antigen(s) detected by the anti-NS-5 antiserum was found in similar quantities on young and adult rat and mouse cerebellum; however, it was not detectable on any of 16 clonal cell lines derived from the rat central nervous system. During preimplantation stages of murine development, the antigen could be detected on all cells of (2-4)-cell and (8-16)-cell stages and on the trophoblastic cells of blastocysts by indirect immunofluorescence, Embryos on day 9 of gestation, the earliest tested after implantation, expressed the antigen(s), but expression was restricted to the nervous system.


The gating currents of sodium channels: pore-population-size effects.

Sodium-channel behavior has been modeled in order to determine the answer to the following question: How large must a population of "on-off" sodium pores be before the inherently random behavior of the individual channels becomes smoothed to yield the expected gating current-conductance relationships which would be predicted from an infinite pore array? Results of this analysis show that for the "opening" situation, an excellent fit was obtained whenever more than about 10 pores were considered. Significant discrepancies were observed in the "closing" situation, however, for pore arrays of 50 or less. Marked hysteresis is apparent in the behavior of small port populations.


Comparison of the structural and chemical composition of giant T-even phage heads.

A study has been made of the structure of the capsids of T4D giant phage produced from mutants in gene 23 and temperature-sensitive mutants in gene 24, and T4D and T2L giant phage formed by the addition of L-canavanine followed by an Larginine chase in the growth medium. All the giant phage capsids have been shown to be built according to the same geometrical architecture. This consists of a near-hexagonal surface net, lattice constant 129.5 A, folded into a left-handed T = 13 prolate icosahedron elongated along one of its fivefold symmetry axes. Their only apparent difference from wild-type T-even phage capsids is their abnormally elongated tubular part. A comparison of the capsomere morphologies and protein compositions of the giant phage capsids showed that all T4D giants are identical but differ from T2L: The T4D capsomere has a complex (6 + 6 + 1)-type morphology, whereas the T2L has a simple 6-type. T2L phage, however, lack two capsid proteins, "soc" and "hoc", present in T4D. The difference in capsomere morphology can therefore be related to the difference in the protein compositions of these two phage. Possible differences between the initiation and means of length regulation of giant phage heads and the aberrant polyheads are discussed.


Effects of RNase and RNA on in vitro aster assembly.

RNase alters the in vitro assembly of spindle asters in homogenates of meiotically dividing surf clam (Spisula solidissima) oocytes. Some effects of RNase, such as reduced astral fiber length, appear nonenzymatic and probably result from RNase binding to tubulin. However, RNase-induced changes in the microtubule organizing center are also observed. Since other polycations can mimic RNase effects, the existence of an RNA component of the spindle organizing center remains uncertain. Effects of RNase and other polycations on astral fiber length can be prevented and reversed by the RNase inhibitor, polyguanylic acid. Polyguanylic acid can also augment astral fiber length in the absence of added RNase or other polycations. Augmentation by polyguanylic acid is favored by high ionic strength, and can be duplicated by polyuridylic acid and, with less efficiency, by polyadenylic acid. Polycytidylic acid and unfractionated yeast RNA, however, are unable to augment aster assembly. Polyguanylic acid can also augment the length of astral fibers on complete spindles isolated under polymerizing conditions. These results demonstrate that specific polyribonucleotides can alter spindle assembly in vitro. The presence of an inhibitor of microtubule assembly in Spisula oocytes, which can be inactivated by specific RNAs, is suggested.


[Changes in thromboelastogram in women on hormonal contraception].

The authors have analysed changes in the thromboelastogram in 411 women on oral contraceptives and in 31 women on no hormonal contraception. Comparing the results they found no statistically significant differences because the control group was too small. In the group of women on hormonal contraception, statistically significant differences were recorded in those women whose thromboelastogram was analysed several times, the differences having been more pronounced in the women that had used hormonal contraceptives for a longer time. As the appearance of thrombo-embolic complications is a very complex process, the authors' opinion is that thromboelastogram cannot be considered as a routine method for predicting these complications.


[Success in the induction of labor by peroral administration of Prostin E 2 in relation to Sandopart].

The results of the use of Prostin E2 in the induction of labour in 46 pregnant women were compared with the results obtained by Sandopart in 40 pregnant women. To avoid the effect of amnyotomy, both groups were examined without carrying out routine amnyotomy. The results have shown that a significantly better efficacy in the induction of labour was obtained with Prostin E2. This efficacy was very good regardless of the cervix assessed by the Bishop score, while the reaction of the uterus to Sandopart proved the poorer the lower the Bishop score. The mother's condition, established by clinical and laboratory examinations, did not change significantly in the course or after the administration of Prostin E2. Nor did the condition of infants, assessed by the Apgar score, differ from the condition of children from the group of labour induced by Sandopart. This shows that the induction by Prostin E2 is just as efficacious as the induction by Sandopart if the cervix is mature; if the cervix is not mature, the induction by Prostin E2 is even more efficacious.


[Graphic monitoring of the latent phase of intensified labor].

In planned delivery it is often advantageous to be able to monitor the early course of stimulated labour. This paper describes the construction of a graph which defines the rate of progress of the latent phase of augmented labour in 307 women, which represented 80% of a group of patients in a "low risk" category obstetrically.


[Leiomyoma of Bartholin's gland].

Out of 4676 gynecological surgeries, the authors came across one case of the leiomyoma of Bartholin's gland. The clinical picture differed from that in the cystic changes of this gland by its consistency; also the skin, the surrounding tissue, and regional lymphs of the gland were not changed. The authors maintain that all tumorous changes of Bartholin's gland should be treated surgically.


[Malignant melanoma of the skin and pregnancy].

Two women, during pregnancy, suddenly developed changes in the pigmented skin nevus (melanoma) which they had had since their childhood. Both patients were surgically treated; the diagnosis was malignant melanoma. One of the patients, 12 years after the operation, is alive and well, and so is her child. In the other patient, 6 months after operation, there was a relapse and regional metastases. She gave birth to a healthy child.


[Torsion of the pregnant uterus].

Torsion of a 6-month gravid uterus in a secundigravida, showing the clinical shape of an acute abdomen and shock, is described. The uterus was twisted 180 degrees from left to right, with a retroplacental haematoma and dead foetus. The symptoms occurred while the patient was sleeping. Sectio caesarea was performed and no other pathologic changes were found in the uterus, ovaries, or minor pelvis.


[Abdominal pregnancy].

A 38-year-old woman, after a spontaneous abortion following extrauterine pregnancy, developed abdominal pregnancy which was diagnosed only 6 days before the term of delivery, although she had been regularly examined. In the first trimester of that pregnancy she wanted to interrupt pregnancy and an alleged artificial abortus was performed. By cesarean section a live, at term baby, 3000/50, was born without any visible malformations. The placenta was left in situ because it partly adhered to the colon sigmoideum, mesosigma, and the wall of the small pelvis. Although it is better in abdominal pregnancy with cesaren section to remove the placenta immediately, the authors think that to leave the placenta in situ is safer if its position is such that to remove it would expose the patient to great risk.


[Late gestoses complicated by amaurosis].

A case of amaurosis in the course of preeclampsia and one in eclampsia are presented. Since in both cases conservative therapy failed, the cesarean section was applied in both cases. The infants were of low birth weight but developed well. Amaurosis in both patients disappeared a few days after delivery. In such cases the authors advocate liberal indications for cesarean section.


[2 cases of amaurosis during pre-eclampsia in pregnancy].

The author describes two cases of amaurosis in toxemia during pregnancy. Both pregnancies were completed by cesarean section. Vision returned to both patients on the third and the fourth day, respectively, following delivery. The follow-up findings 9 months after delivery were normal.


[Bilateral extrauterine tubal pregnancy].

The authors analyse their surgical material over 17 years. Out of 4676 gynecological operations, 416 related to extrauterine pregnancy, and only one of them was bilateral extrauterine pregnancy. The diagnosis in the latter case was made during the operation. The initial diagnosis was confirmed pathohistologically. The authors point out that during the operation it is necessary to control both ovarian tubes and that the material removed by surgery should always be examined pathohistologically.


[Acute gangrenous cholecystitis with suppurative acute cholangitis in the 1st days of the puerperium].

A 25-year-old secundipara developed acute gangrenous cholecystitis coupled with suppurative cholangitis on the fourth pureperal day. The patient recovered after cholecystectomy and choledochotomy. It is pointed out that cholelithiasis is not rare in pregnancy but acute cholecystitis is very rare, especially in the puerperium. For this reason the diagnosis is difficult, yet the final issue depends on its early establishment and also on the early surgical intervention.


[Use of aspiration curettage in ambulatory patients].

In 90 patients with metrorrhagia, aged 20-75, aspiration curettage with constant aspiration by a vacuum pump was applied. The most frequent clinical diagnosis was metrorrhagia dysfunctionalis (in 55 patients). The aspiration was performed without cervical dilatation, by using one ampoule of valoron i. v. by a cannula 3 mm in diameter and a chamber with a built-in sieve for collecting aspiration material. Histological analysis revealed endometrial carcinoma in 4 cases, post-abortion conditions in 29 cases, endometrial hyperplasia in 28 cases, while in the remaining patients the endometrium was normal. In 4 cases there was not enough material for analysis.


[Vacuum extraction in interruption of pregnancy using a jagged cannula].

The author describes his experience with artificial abortus using vacuum aspiration performed with a jagged cannula of his own construction. In 2150 interruptions of pregnancy, the complications were as follows: residua in 0.2%, bleeding in 4.7%, and febrile condition in 2.5% of cases. The loss of blood was 30-200 ml.


[Tocolysis in prevention of spontaneous abortion].

In the course of 1975 and 1976 the authors applied Partusisten (Th 1156 a) in 34 pregnant women at the risk of spontaneous abortion in the 16th to the 28th week of pregnancy. The therapy started with intravenous infusions by means of an automatic electromechanic infusion pump; peroral application of the drug followed, both in hospital and for a certain period in outpatient treatment under the gynecologist's supervision. Out of 34 women, 27 remained pregnant for more than 37 week of gestation and gave birth to a live at-term baby; in 5 cases the success was relative, and only in 2 cases was there no success at all. According to the tocolysis index, at index 2 or less, the success was achieved in 87% of cases and at index exceeding 2, the success was achieved in 63% of cases. The side-effect observed was invariably tachicardia in the mother, while all other untoward effects (tremor, sweating, slight restlessness, etc) were tolerated very well. An extremely good effect of Partusisten is obvious, because in doses of 4 micrograms/min, it promptly reduces the frequency and intensity of contractions.


[Method of evaluating the acoustic properties of devices for auscultation].

It is suggested that the appraisal of acoustic properties of auscultation instruments should be done by an expert-physician by following the most outstanding auscultative characteristics. A procedure for medical appraisal of acoustic properties is proposed. The BF-1 sthetophonendoscope manufactured by the Nizhny-Tagil medical instruments plant is recommended to serve as a model one.


[Longitudinal radioisotope tomograph].

To-day the construction of an apparatus for longitudinal emissive tomography has become a problem of great urgency. The designed apparatus, as described herein, is based on the principle of the image superposition method and the results obtained are suggestive of possibilities for its efficient application in diagnosing diseases involving large organs, such as the brain, liver, etc.


[Increase in the information content of the image of the surface veins by using a television infrascope].

An enquiry into the possibility of obtaining an infrared image of superficial veins by using a TV infrascope demonstrated this method to be more sensitive by comparison with the IR-photography. The former procedure enables it to obtain a picture of the venous network superior by its informativeness to that obtained with the aid of IR-photography. This justifies recommending the procedure in question for the purpose of diagnosing conditions in which there appear changes in the superficial veins, in particular for diagnosing pregnancy, characterized by a progressive development of venous anastomoses in the region of the mammary glands.


[Methods and modern apparatus for assisted circulation. The basic trends in their development].

A systematization of methods for assisted circulation, based on the formulation of a concrete procedure, the nature of the deranged or lost function substitution and conditions for effective realization of such a substitution, is offered. This made it possible to classify the equipment for assisted circulation and to analyze the current trends of its further development. The most characteristic automation levels of the equipment under consideration and of generations of some apparatus, differing in the degree of automation, control and monitoring the process of assisted circulation, are presented in the form of tables and pictures.


[Problems of medical equipment terminology].

It is recommended to standardize the biomedical engineering terminology by making use of greek latin terminological elements. The designations of biomedical engineering products should include terms featuring the fundamental functions of their technical arrangements, viz. the type of action, the method of examination, the surgical manipulation, the kind of treatment, by retaining the already established clinical terms. The second part in the designation of the technical arrangement should carry the name of the organ, cavity, region and system of the organism, of the tissue, etc, for whose handling the instrument or apparatus is intended.


[Presterilization treatment of medical instruments for the purpose of lowering the sterilizing dose of gamma irradiation].

Preliminary treatment of medical instruments with a 1% sulphochlorantine solution for a period of 3 hours helps greatly reduce their initial contamination, permits it to lower the sterilizing irradiation dose down to 1.5 Mrad and to manufacture radiationally-sterilized medical instruments at any medical instruments plant. The instruments subjected to presterilization treatment in conjunction with radio-resistent irradiation are non-toxic, apyrogenic and free from any functional changes.


[Frequency-contrast characteristics of an x-ray image intensifier].

To analyze intricate roentgeno-diagnostic complexes the need for application of frequency-contrast characteristics (FCC) is generally acknowledged at present. The paper presents a description of procedures used in an experimental definition and analysis of three-dimensional characteristics of roentgen image amplifiers constructed with a roentgen electron-optic converter serving as a base. As a result of an experiment the FCC of individual components of the amplifier have been determined, critical links in the device educed and the summary FCC of all its channels calculated. Possible ways of improving the parameters of the Soviet-made units are indicated.


[Methods of cardiac synchronization in assisted circulation].

In assisted circulation cardiosynchronization should be regarded as a process of monitoring the arterial blood pressure within the limits of the cardiac cycle and changes of its form with the aim of improving the energy balance of the heart. The coordination of the pumping function and that of the cardio-vascular system comes to a problem of shaping the monitoring action that depends upon three variables, viz. the time lag tepsilon, actuation of the unit relative to the base cardiosignal, duration of the pumping phase  tpi and the signal level at the pump's inlet U(t). A number of researchers consider tepsilon and tpi to be a function of the cardiac contractions period and determine them in different ways, employing for this purpose extrapolation, stochastic characteristics, etc. Of late, in addition to the period of cardiac contractions extremal, mean integral values of the systolic and diastolic pressure, the level of pressure at the instant of the cardiac valves closure and others have also come in use. There are shortcomings in the proposed cardiosynchronization algorhythms: their empiric nature and also the fact that the monitoring action includes merely variables tepsilon and tpi and does not carry function U(t), which reflects the intensity of the pump's operation.


[Use of polymethylmethacrylate for intensifying the treatment of steel parts in rotating containers].

Basic regularities governing the surface dispersion of lwo-carbon grades of steel in a polymer-abrasive medium during treatment of workpieces (the deburring, descaling and rounding of sharp edges) in revolving drum-containers were investigated. Relationships between the amount of the metal scraped off and the consumption of the abrasive filler, on the one hand, and the percentage of the polymer, on the other, as well as the influence exerted by the metal dispersion products and abrasive granules amassing in the containers of these relationships are shown. It is pointed out that the modification of the technological medium by adding polymethylmethacrylate to it helps increase the efficiency of the operation by a factor of two.


[Cryocatheter-tourniquet].

To simplify the design of the cryo-instrument and to adapt it to the forms and dimensions of the organ undergoing surgery or of any other object a cryocatheter-tourniquet is proposed, where a thin-walled, flexible tube passed in a loop like-manner through the opening of another tube (after the type of a tourniquet), is used as a conduit of the cooling agent. The loop out on the object to be operated upon forms the working part of the cryosurgical appliance.


Effect of catecholaminergic drugs on epileptogenic properties of the caudate nucleus.

Drugs stimulating catecholaminergic transmission (dopa, apomorphine, amphetamine, and their combination with disulfiram) weakened the epileptogenic properties of the caudate nucleus in freely moving rats. Under the influence of these drugs the cortical electroencephalographic response to single stimulation of the nucleus was shortened in animals receiving subconbulsant doses of leptazol and the intensity of the spike-wave rhythm bound with repeated caudate stimuli was reduced. Conversely, inhibitors of catecholaminergic transmission (chlorpromazine, haloperidol, alpha-methyltyrosine, and disulfiram) potentiated the epileptogenic effects of the caudate nucleus.


Functional organization of sleep states in normal and brain-damaged infants.

A polygraphic investigation was made of daytime sleep in healthy infants with analysis of the EEG, oculogram, muscle tone, fluctuations in skin resistance, respiration, ECG, rheoencephalogram, and rheogram of the leg. Infants with cerebral palsy of perinatal genesis were investigated by the same method. The results showed that in early infancy it is possible to distinguish the basic stages of slow sleep and the stage of fast sleep, although the electroencephalographic experssion of these stages in infants has special features of its own. The age dynamics of the polygraphic picture of sleep shows that the electroencephalographic, autonomic, and motor components of sleep, although clearly coordinated in the various stages, have at the same time considerable autonomy. This is confirmed by the results obtained by analysis of the cerebral pathology. The need for adequate assessment of this complex function in order to elucidate the physiological nature of sleep is emphasized.


State of the hypothalamic-pituitary neurosecretory system in rabbits with anaphylactic shock.

The hypothalamic-pituitary neurosecretory system of rabbits with anaphylactic shock was investigated by morphometric and histochemical methods. The volumes of the perikarya were increased and the dimensions of the nuclei and nuclei of the neurosecretory cells were reduced, and the content of neurosecretory substance throughout the neurosecretory system was increased. In rabbits dying from shock the volumes of the nuclei and nuclei were reduced by a lesser degree, the dimensions of the perikarya were changed, and the content of neurosecretory substance in the posterior lobe of the pituitary was reduced. In animals surviving shock the synthesis of neurohormones by the neurosecretory cells was thus sharply stimulated, but liberation of neurohormones from the posterior lobe was inhibited. In aminals dying from shock hormone formation in the neurosecretory cells was stimulated to a lesser degree, but the processes of liberation of neurohormones from the posterior lobe of the pituitary were probably intensified.


Mechanism of visual perception of movement.

We here present a logical mathematical model for the visual perception of movement in man; it is based on the treatment of signals in the retina in relation to time and distance and on the statistical theory of the separation of signal from noise in the visual system. It shows good agreement with experimental results and has made it possible to determine the comparative level of internal noise of the visual system, the mean rate of spread of excitation from the photoreceptors along the surface of the retina, and many other characteristics.


Multiplication of the late slow component of the evoked potential to light during chlorpromazine administration.

In experiments on unanesthetized rabbits with electrodes permanently implanted into various brain formations the effect of chlorpromazine was studied on the phenomenon of multiplication of the late slow component of the evoked potential to flashes of light applied at a frequency of 1 Hz, some of which were given simultaneously with electric shocks to the hind limb. Chlorpromazine was found to reduce the multiplication of the slow component to flashes applied without electric shocks and to facilitate the reduplication of this component to flashes applied along with the nociceptive stimulation. In the discussion of the results a role of adrenergic structures is postulated in the formation of the defensive action acceptor, one of the most important and crucial mechanisms of the functional system.


Some features of the medium surrounding the mechano- and electroreceptors of the acousticolateral system of the ray Raja clavata.

The degree of binding of K ions has been investigated and the contents of free Ca ions and of glycosaminoglycans have been determined in the medium surrounding the mechano- and electroreceptors of the acousticolateral system of the ray Raja clavata; in addition, electrical phenomena in solutions of K hyaluronate in solutions of the media investigated have been studied. A comparison of the results of electrometric and chemical analysis has shown that the proportions of bound K ions as percentages of the total amounts of these ions are 36.4 in the endolymphatic jelly, 39.6 in the ampullar jelly, and 21.9 in the liquid of the lateral canals. The amount of Ca ions in the media investigated is 3.6-4.4 meq/liter and is close to the concentration of these ions in sea water--3.4 meq/liter. In the endolymphatic jelly the amount of glycosaminoglycans is 0.30+/-0.022% of the wet weight, in the liquid of the lateral canals 0.21+/-0.026%, and in the jelly of the ampullae of Lorenzini 2.79+/-0.28%. Some characteristics of the "displacement potentials" of solutions of K hyaluronate and solutions of the jelly of the ampullae of Lorenzini have been determined, and some hypotheses have been put forward on the possible role of these potentials in the activity of the ampullar formations of the systems of organs of the lateral line.


Activity of the neurons of the medial region of the septum of the rabbit brain in early ontogenesis.

In rabbits aged from seven days to two and a half months the activity of individual cells of the nucleus of the diagonal band of Broca (NDB) and of the medial nuclei of the septum (MNS) of the brain and the EEG of the dorsal hippocampus (DH) - the CA2-CA3 zones - have been recorded simultaneously. It has been found that the specific (burst) activity of the neurons of the septum appears first on the 8th-11th day of the background of the action of eserine. The distinct bimodal nature of the histograms of the interimpulse intervals characteristic of the burst sequence of distribution of the potentials appears only from an age of 14 days. The deficient nature of impulse-formation of the NDB and of the MNS is acquired at about the 20th day of life. A parallel evolution of the impulse activity of the cells of the medial region of the septum and the synchronized activity of the hippocampus in ontogenesis is traced. The formation of the theta activity correlates with an increase in frequency of the burst activity of the neurons of the septum connected with an increase in the mean frequency of impulse formation of the cells, the concentration of the impulses into a packet, and the growth of the regularity of the burst discharges with age.


[Dyssymmetrical cytotomy and orientation of the spindles in early isolated blastomeres of gastropod molluscs].

While removing the vitelline membrane mechanically or by trypsinization, one or two blastomeres were isolated from two-, four- and eight-celled embryos Lymnaea stagnalis, Physa fontinalis and Ph. acuta. If a pair of blastomeres was isolated prior to the formation of the III and IV cleavage spindles, it became similar to a two-cell embryo; the spindles oriented in parallel to each other and the contact zone of blastomeres preserving the previous localization of the nuclei and the subsequent division was equal. If a pair of blastomeres was isolated in metaphase, the localization of spindles did not change and the relative size of sister blastomeres after the subsequent division resembled the normal size (in particular, the III division was unequal). In the course of division of isolated single blastomeres, as well as pairs of blastomeres with parallel spindles, mutual turns of sister cells along the plane of new furrow, always dexiotropic in Lymnaea and laetropic in Physa, were observed in all cycles. The ability of dissymmetrical invariant turns during cytotomy, shown earlier when studying the whole embryos, is, thus, inherent to each blastomere irrespective of the neighbour ones but is supressed during the normal development after the III division mechanically due to the dense cellular packing projected by the orientation of spindles.


Submicroscopic localization of H3-noradrenaline in the hypothalamus.

The submicroscopic localization of H3-noradrenaline in the periventricular region of the anterior hypothalamus of the rat was investigated. It was shown that the largest concentration of the label is detected in the neuroglia of the subependymal layers, where the label is detected above the terminals of the axons with two types of vesicles and along the path of the axons above the microtubules. More rarely the label is encountered above the terminals with one type of synaptic vesicle and above cells of the neurosecretory type, similar in ultrastructure to cells of the arcuate nucleus. In the ependymal layer the label is localized above the cells and intercellular spaces. The results of the work are discussed in connection with the modern data on the fluorescence of the catecholamines of the hypothalamus.


[Expression of the paternal genes for lactate dehydrogenase, glutamate dehydrogenase and acetylcholinesterase in the development of hybrid fish between species from the families of Cobitidae and Cyprinidae].

The time of expression of the paternal genes of glutamate dehydrogenase (GDH), lactate dehydrogenase (LDH) and acetylcholine esterase (AChE) was investigated in the development of fish hybrids. The species which differed by the thermostability of homologous enzymes were selected as parental pairs. The appearance of differences in the thermostability of homologous enzymes between the hybrids and the maternal species suggested the beginning of paternal enzyme synthesis in the hybrid embryos. Differences in the AChE thermostability appeared simultaneously with the enzyme activity at the stage of first muscle contractions (35 hrs of development), differences in the mitochondrial GDH thermostability appeared at the stage of hatching (50-60 hrs) and those in the LDH thermostability 12-17 days after hatching. The total activity of AChE and GDH sharply increased during the period of the paternal enzyme appearance whereas the activity of LDH suffered practically no changes. Differences in the AChE thermostability between the hybrids and the maternal species are the same for both the total AChE (in supernatant, 15,000 gX10 min.) and the solubilised AChE (in supernatant, 130,000 gX60 min.). AChE of the parental species and the hybrids have the same electrophoretic mobility. The differences in the thermostability of enzymes are preserved following the electrophoresis in polyacrilamide gel.


The spectrum of the calling signals, phonotaxis, and the auditory system in the cricket Gryllus bimaculatus.

In behavioral experiments with a Y labyrinth it was shown that phonotaxis in the female crickets in respect to the calling signals (CS) of the males depends on the spectrum of the signal. The necessary and sufficient condition for development of normal phonotaxis is the preservation of the first, low-frequenct (LF) component of the spectrum (5kHz). Signals with a time pattern identical to that of a CS but with a spectrum containing only the high-frequency (HF) component (12.5 kHz) do not evoke phonotaxis. HF signals in the frequency-range 10-40 kHz evoke negative phonotaxis in females under conditions of "tethered flight". In the auditory system of the crickets, beginning with the tympanal organ, there is a clear separation of the elements effecting LF and HF signals. Two types of ascending interneurons transmitting acoustic information from the primary auditory center to the brain are described in detail. The first is connected primarily with LF receptors and transmits clearly all the time-dependent characteristics of the CS most important for recognition. The second apparently participates in the production of negative phonotaxis. It is connected primarily with HF receptors, has considerable after-effect and also raises sensitivity to sounds of low intensity, emphasizes the initial moment in the effect of a stimulus, and "habituates" rapidly to repeated stimulations.


[Pathways of terminal erythrocyte differentiation in birds. An analysis of the intermediate forms].

The erythropoiesis during anemia is characterized by the reduction of the bone marrow period of cell development. Two immature forms, absent in the normal state, were shown to be present under anemia: basophilic erythroblasts and reticulocytes with basophilic cytoplasm. These forms are interposed between the bone marrow basophilic erythroblasts and erythrocytes. Some basophilic erythroblasts turn out in the peripheral blood and transform into basophilic reticulocytes there. The level of transcription in anemic animals during the transformation of basophilic erythroblasts into basophilic reticulocytes does not decrease and is higher than that in polychromatophilic erythroblasts. The total chromatin condensation does not reflect the decrease of the transcription level.


[DNA synthesis in the brain and liver of rats in various stages of postnatal development].

The intensity of incorporation of 3H- and 14C-thymidine in the brain and liver DNA in rats of different ages was investigated. It was proved that both the replicative and oxyurea-resistant DNA synthesis might proceed in the rat brain cells. The intensity of these processes changes sharply during postnatal development.


[Morphological, cytochemical and radioautographic analysis of the development of a population of mitral cells of the rat olfactory bulb in prenatal ontogeny].

The dynamics of DNA synthesis, its ratio to the proliferative activity and changes in the amount of genetic material in mitral cells of the white rat olfactory bulb during prenatal ontogenesis, as well as in newborn rats are considered. The lengthening of G2-phase, decrease of mitotic activity and increase of DNA content in the nuclei of forming mitral cells were shown to occur in the period from 18 till 20 days of embryogenesis.


Effect of a unilateral cortical lesion on the monoamine content in the cat brain.

The serotonin and noradrenalin content in the cerebral cortex, hypothalamus, and mesencephalon was investigated spectrofluorometrically in 12 cats on the 5th-6th day after the production of a pathological focus in the region of the occipital cortex. Diffuse changes of brain activity were recorded on the EEG at this period: spike-like waves and slow waves of increased amplitude. A considerable increase in the serotonin concentration was observed in the cortex, with the effect predominant in the region immediately adjacent to the pathological focus. A tendency for the serotonin level to fall was observed in the hypothalamus and mesencephalon. The noradrenalin concentration in these brain structures showed no significant change. The role of serotoninergic structures of the brain in the mechanisms responsible for restoring the functional state of the brain after experimental injury is discussed.


[Localization of aldolase activity in the embryos of loach].

The activity of aldolase was determined in different parts of the loach (Misgurnus fossilis L.) embryo at the stages from the formation of axial organs till the beginning of embryonic movements (from 19 till 38 hrs of development at 21.5 degrees). In all parts of the embryo, the activity of aldolase at first decreased (21-23 hrs) and then increased. The region of somites is characterized by the highest absolute and specific activity at all developmental stages. The increase in the number of somites is accompanied by the fall and subsequent rise of aldolase activity. In the somites of different degree of differentiation, the enzyme activity changes in a similar way. Hence, there is no correlation between the morphological and biochemical differentiation of somites. Differences in the specific aldolase activity between the anterior and posterior halves of the embryo and the regions of head, somites and tail were found at the stages of 19-23 hrs of development. The maternal aldolase only is present at these stages, as was shown earlier. It means that the early stages of biochemical differentiation may be realized not by means of differential activation of genes controlling the enzyme, but by means of regylation of translation on the templates stored in oogenesis.


[Effect of metopirone and glucocorticoids on the glycogen content in the adrenals of rat fetuses].

Metopiron, hydrocortisone and dexamethazone are able to influence different links of the hypothalamo-hypohysial-adrenal system and induce the inhibition of glucocorticoid function. Changes in glycogen content in the adrenal gland and liver of rat foetuses under the effect of the drugs in question were studied. It was shown that metopiron exerted no marked influence on the level of glycogen in the adrenal gland and decreased 2.5 times that in the liver. On the contrary, hydrocortisone and dexamethazone increased the glycogen content 2 times in the adrenal gland and did not change that in the liver. The results obtained agree with the hypothesis on the relation between the glycogen level in the adrenal gland and the level of its hormonal activity and are considered as an additional proof of the functioning of hypothalamo-hypophysial-adrenal system during the last days of the rat prenatal development.


Functional characteristics of stretch receptors of flight apparatus of cockroach Periplaneta americana.

The functional characteristics of the stretch receptors of the wing joints of Periplaneta americana were examined and the possible functional role of these receptors in the maintenance of a stable rhythm of flight is discussed. The stretch receptors of the wing joints are of the phasic-tonic type, with slow and incomplete adaptation by the receptors which discharge upon movement of the wing upward. The nature of the impulse response of a receptor depends both on the angle and the rate of movement of the wing membrane. The arrangement of a hypothetical pacemaker of the insect's wing beats is discussed in detail.


[2 unusual cases of early embryogenesis].

Two unusual cases of early embryogenesis are described: a giant cleaving egg and the presence of two generations of embryos in the genital tract of a female--at the stage of implantation and at the stage of two blastomeres. The ability of development of the second generation was tested in vitro experiments.


Inhibition of visceral pain by electrical stimulation of the periaqueductal gray matter.

Numerous recent studies demonstrated that electrical stimulation of the periaqueductal gray matter (PGM) can result in powerful analgesia to pain of somatic origin. In the present study, we have developed a visceral pain test employing intraperitoneal injection of hypertonic saline which yields a writhing response in the adult rat more reliably than other pain-producing substances. With this test we show that writhing as well as the response to radiant heat (tail flick test) are completely inhibited in all animals with PGM electrode placements.


Responses of intradental nerves to chemical and osmotic stimulation of dentine in the cat.

Recordings have been made of the neural responses evoked by stimulation of dentine with solutions of NaCl, NH4Cl and dextrose. Stimulation of the outer dentine produced no response. From the inner dentine, a smaller number of impulses were recorded with solutions of NaCl than with corresponding concentrations of NH4Cl, but a much larger number than with solutions of dextrose. The discharge evoked by a solution increased in mean frequency and decreased in latency as the thickness of dentine was reduced. The responses suggest that the receptors were in the innermost dentine or the pulp and that they were excited by changes in extracellular fluid composition rather than by osmotic effects. The properties of the receptors appear to be different from those involved in pain from dentine in man.


Illness behaviour syndromes associated with intractable pain.

One hundred patients, referred for the management of intractable pain, completed a 52-item Illness Behaviour Questionnaire (IBQ). Responses were scored on 7 scales: general hypochondriasis, disease conviction, psychological versus somatic perception of illness, affective inhibition, affective disturbance, denial, and irritability. IBQ scale profiles were subjected to numerical analysis and 6 taxonomic clusters were identified. Patients in groups 1-3 were characterized by a relatively non-neurotic, reality-oriented attitude to illness, as indicated by low scores on the first three scales. Patients in groups 4-6 manifested greater evidence of 'abnormal illness behaviour', and presented syndromes resembling 'hysteria', 'conversion reaction', and 'hypothchondriasis' respectively.


Words of chronic pain.

An analysis of the language of pain complaints, employing categories of descriptors, was used to determine if chronic pain of either psychiatric of organic origin might be depicted in terms specific for the disease. The complaints of 128 patients with chronic pain were studied for characteristic patterns. Patients with pain of organic etiology used sensory-thermal (e.g., hot, burning) words more frequently than those with pain of psychiatric origin. Female patients with pain attributed to anxiety used sensor-temporal words (e.g., throbbing) more frequently than those with other psychiatric diagnoses. There was also a statistically significant preponderance of pain on the left when the groups of patients with physical and psychological illness were combined.


Differential effect of morphine on trigeminal nucleus versus reticular aversive stimulation: independence of negative effects from stimulation parameters.

Electrodes were implanted in mesencephalic, pontine, and bulbar reticular formation, and in spinal trigeminal nucleus and tract of rats. Central and peripheral aversive response thresholds  were studied under normal conditions and with morphine. Peripherally elicited aversive reactions were assessed with tail-flick, hot-plate, and footshock responses. Centrally elicited aversive reaction thresholds were in all cases based on unconditioned behavioral distress signs (non-stereotyped, escape-like movements, vocalization, freezing, excretion, etc.) and confirmed in some cases with avoidance learning. Morphine (10 mg/kg) elevated the unconditioned aversive reaction threshold for brain stimulation in the trigeminal complex and for peripheral aversive stimulation, but failed to affect the thresholds for reticular brain stimulation. The failure to affect reticular thresholds was independent of stimulation frequency. Thresholds for 5 and 200 Hz sinusoidal stimulation were both unaffected as were previously reported thresholds with 333 Hz pulsatile stimulation. Trigeminal nucleus and tract stimulation were affected in similar degrees. The data were discussed as supporting descending inhibitory models of opiate analgesia.


Modulation of shock-elicited pain by acupuncture and suggestion.

An experimental investigation of acupuncture's analgesic potency, separated from suggestion effects, is described, in which judgments of shock-elicited pain of the forearm were recorded along two separate scales: intensity and aversiveness. Data from experimental subjects, who received electrical acupunctural stimulation through surface electrodes located over acupuncture points and were given explicit counter-suggestions of sensitization, were compared to those obtained from control subjects, who received such stimulation over incorrect loci and were given explicit suggestions of analgesia. No alterations in the perception of pain intensity, either by acupunctural stimulation or suggestion, could be detected at any time during the experiment, but stimulation of the correct points produced a significant analgesic reduction in aversiveness which was specific to the arm so stimulated, overcame the counter-suggestion of sensitization, and persisted after stimulation was discontinued. No significant reductions were recorded from control subjects. These findings are interpreted in light of other experimental acupuncture research, and of the demonstrated mode of action of analgesics of proven efficacy.


[Modification of the method of transauricular hypophysectomyA1].

The authors describe a modification of the method of transauricular hypophysectomy. Anatomical reference-points suggested permit to direct the extractor directly to the gland without any use of additional instruments (goniometers, apparatus for fixation of the animal head, etc.). A detailed description of the course of the operation and of the instruments used is presented.


[Method of study of epidemiology of diabetic angiopathies].

The authors present a method of a perspective study of the epidemiology of diabetic angiopathies with the use of standardized methods of examination of the cardiovascular system, including the assessment of microangiopathies and also glycemia and lipid metabolism indices in accordance with the WHO recommendations. This method can be used by endocrinologists, therapeutists and physicians of other specialties in studying the factors influencing the development of vascular affections in patients with diabetes mellitus.


[Clinical characteristics of selectivity of proteinuria in patients with diabetes mellitus].

A study was made of 43 patients suffering from diabetes mellitus using the method of proteinuria selectivity on polyacrylamide gel. Two types of proteinuria were distinguished: the first type repeated the electrophoregram of the plasma proteins completely or partially, the second type--the selective one--was characterized by excretion of individual plasma proteins. Diagnostic and prognostic value of the method of proteinuria selectivity is discussed.


[Androgenic function of the adrenal glands in children with acceleration of the growth and development].

A study was made of the urinary excretion of neutral 17-ketosteroids (sum total and individual fractions) in 65 accelerated children, aged from 7 to 16 years. The information on the excretion of androgenic compounds pointed to an earlier and increased functional activity of the adrenal cortex and gonads in children with acceleration of the growth and development.


[Mechanism of the effect of hydrocortisone on the lymphoid cell lipids].

It was experimentally established that a single administration of hydrocortisone to rabbits in a dose of 50 mg/kg caused a reduction in the lymphoid cells of the mesenteric lymph nodes of triglycerides and free fatty acids; this was accompanied by a fall of total lipids in the cells.


[Effect of hydrocortisone on sodium and potassium distribution in the sections of the cerebral cortex of rats after their electric stimulation].

Sections of the rat brain cortex were incubated in various physiological media using container-electrodes, similar to the McIlwain's type. The shifts of sodium and potassium distribution between the extra- and intracellular spaces of the slices after different stimulation parameters and the subsequent restoration were measured. The administration of hydrocortisone (for 7 days, 5 mg/100 g daily) usually increased the response of the slices to the stimulation in incubation in the glutamate devoid medium. When 0.2--0.5 mM of glutamate was added to the media the effect of hydrocortisone disappeared. Possible physiological significance of the mentioned results is discussed.


[Classification of the main kidney diseases in diabetes mellitus].

In the suggested classification of affections of the kidneys in diabetes mellitus the main attention is paid to the vascular genesis of the appearing disturbances. The terms used formerly ("diabetic glomerulosclerosis", "diabetic nephropathy") failed to reflect the primary affections of the vessels. The following new terms are suggested: "diabetic microangionephropathy" (affection of the small vessels), "macroangiography" (affection of the large vessels), "diabetic angionephropathy" (complex affection of the renal vessels). "Pyelonephritis" (acute and chronic) was also introduced into the classification due to its exceedingly frequent occurrence in diabetes. The term "diabetic nephropathy" is suggested for complex affection including diabetic angionephropathy and pyelonephritis. Diabetic microangionephropathy should be divided into four clinico-laboratory stages; their characteristics are presented. Particular attention was paid to the accessibility of their diagnosis in medical institutions.


[Development of alloxan diabetes and its effect on the sexual system of male rats under conditions of alpha adrenergic receptor blockaders].

A study was made of the influence of the block of the alpha-adrenoreceptors in male rats on the development of alloxan diabetes and on such its complication as depression of the sexual system function. Phetholamine sharply decreased the death of the animals the first 3--4 days after the alloxan administration: only 5.3% of the animals died. As to rats with intact alpha-adrenoreceptors--42% of the died. Block of the alpha-adrenoreceptors decreased the percentage of rats with marked diabetes. In 37.2% of rats given alloxan and phentholamine diabetes was very mild or failed to develop entirely. Phentholamine significantly lowered the depressive effect of alloxan diabetes on the sexual system considerably.


[Quantitative evaluation of the dose-response relationship after intramuscular administration of testosterone and its esters].

Experiments were conducted on rats. A study was made of the reaction of target organs to the intramuscular injection of androgenic preparations--testosterone and its esters (acetate, propionate, phenylpropionate, isocapronate, enantate and caprinate) comparison with anabolic methylandrostendiol. An equation is presented for mathematical description of the dependence of the androgenic effect on the dose of the praparations injected, used in a wide range of doses. The equation coefficients proved to have a definite physiological sense.


[Analysis of various components of the mechanism of stimulation of transepithelial sodium transport by catecholamines].

A study was made of the influence of adrenaline of certain components of the transepithelial sodium transport system in the frog skin an on energy sources providing its activating effect. Adrenaline proved to increase the sodium transport through the frog skin decreasing its electrical resistance. Strophanthin K prevented the reaction of frog skin adrenaline completely. Monoiodacetate also produced an inhibitory action on the adrenaline effect which was eliminated on addition of pyruvate into the solution. Potassium cyanide and 2,4-dinitrophenol considerably weakened the adrenaline stimulation of transepithelial sodium transport. A conclusion was drawn that an increase of sodiun transport by the frog skin in the action of catecholamines was associated with increase of its ionic permeability and the activation of the ionic pump. It is supposed that the principal source of energy provision for the stimulating effect of catecholamines were processes of aerobic energy metabolism.


[Certain properties of estrogen receptors in the cell nuclei of different organs of rats].

Some properties of the macromolecules, specifically binding estradiol (E2) of salt chromatin extracts of the nuclei of the kidneys, liver, prostate, testes and the uterus of rats were studied. Examination of competition of various unlabeled hormonal preparations with 3H-E2 for the binding sites demonstrated the E2-binding macromolecules of the nuclei of all the organs under study to have a high hormonal stereo-specificity. The E2-binding macromolecules of the nuclear extracts of the kidney, liver and the uterus were sensitive to the action of pronase. In sedimentation with ammonium sulfate of proteins from the 0.3 M NaCl extracts of the nuclei of the kidneys and liver, but not of the uterus, the supernatent fraction of the salt-treated extracts showed an additional (in comparison with control) specifically E2-binding macromolecule activity, sensitive to the action of pronase. An analogous effect of the appearance of additional binding activity could be obtained in heating of the nuclear extracts of the kidney and the liver at 60--100 degress C for 5 minutes.


[Serum calcium evaluation and incidence of primary hyperparathyroidism in hospitalized patients (author's transl)].

Automated laboratory procedures have made possible to "screen" a large population for specific biochemical abnormalities. Primitive hyperparathyroidism is for several respects an excellent disease model for testing "mass screening". Il is often asymptomatic, not uncommon, and is manifested by abnormalities in the levels of serum calcium and inorganic phosphorus, that can be detected cheaply with automated equipment. A computer program has been developed to screen patients with hypercalcaemia. During a period of 18 months 22720 hospitalized patients were investigated by the evaluation of serum calcium, and 80 hypercalcaemic patients were found. The diagnosis of primary hyperparathyroidism was established in 24 patients (in 19 histologically confirmed) so that the incidence of primary hyperparathyroidism (1,05%) compares favorably with that reported from some foreign Authors.


[Behaviour of urinary excretion of lysozyme in renal diseases and in urinary tract infections (author's transl)].

Urinary excretion of lysozyme was investigated in a group of 66 patients with various renal diseases, nephrolitiasis and urinary tract infections. The results obtained demonstrate that the amount of the enzyme excreted is related to the entity of tubular damage whereas is not with glomerular damage. No correlation was found between lysozyme excretion neither to the degree of proteinuria neither to the amount of leukocytes and bacteria in the urine. In patients with urinary infections urinary lysozyme increases only when there is a tubular injury of some entity. In 90 pediatric patients with urinary infection and pyelonephritis lysozyme in the urine was found only in two cases. Therefore urinary lysozyme determination cannot be considered for the detection of early tubular injury and is not a helpful diagnostic tool in urinary tract infections.


[Relation between age, sex and various metabolic parameters: blood uric acid (4776 specimens), blood sugar (7211 specimens), blood cholesterol (5600 specimens) and blood triglycerides (4438 specimens)].

The connection between age, sex and some laboratory parameters (blood uric acid, glucose, cholesterol and triglycerides) has been studied on a very wide whole (22025 exams). An important datum which has appeared is that the increase of age is connected with an increase of the values of the parameters studied, and that the sex conditions differences which proved statistically significant.


[A proposed hepatic pie chart].

The AA. have chosen 12 tests to organize an "hepatic flash" after a selection out of 180 cases scheduled as the table no. I through a set of tests showing step by step any modifications in compliance with the sensibility, reliability, statistical clinical and physio-pathological meaning of each test. The 12 tests are set out by circular abscissae of a circus according to the pathogenetic mechanisms leading to their modifications. By the radial ordinates, instead, it is shown the decreasing and increasing values which every test may assume. An hypothetic line (hepatogram) links then the values set out during the process of the disease in such a manner that the particular shapes assumed by the line itself show quickly and visually the spreading rate of the disease process.


[Utilisation of Olivetti P 652 calculator system for RIA evaluation (author's transl)].

The AA. take into consideration the utilisation of the Olivetti calculator system including the following hardware: P 652 basic unit microcomputer; paper tape reader LN 20; Editor 4 ST typewriter, for RIA evaluation. For this purpose they have compiled a series of generalized programmes that utilise for the calculation of the standard curve, the logit transform fitted by using a linear regression or a cubic regression and the sigmoidal linear logarithmic curve calculated by cubic regression. Other two programmes are described also for automatic data reduction in the detection of hepatitis associated antibody (anti-Australia antigen) and of normalized serum thyroxine.


[Determination of glycemia. Comparison between the enzymatic method and those of Folin-Wu and of ortho-toluidine (author's transl)].

On 1032 serum's samples, the determination of glycemia has been at the same time performed with methods enzymatic, of Folin-Wu and of ortho-toluidine. The obtained results, arranged, with the relative frequency, in progressive order from 40 to 470 mg%, have been compared among themselves, taking as base's value that of the method of Folin-Wu. After a description of the chemical reactions, which occur during the enzymatic determination of the glycemia, and of the causes of error, which can to interfere on the same determination, it has been discussed the validity and the specificity of this method. Effectively this method seems, besides being constantly reproduceable and of simple execution, to consent the best estimation actually possible of the glycemia. It is recommendable a general acceptance of the enzymatic method, executable also with Auto-Analyzer, so that the glycemic values of the same and of the different laboratories could be among themselves comparable.


[Comparison between two automatic methods, chemical and enzymatical, of urea determination in blood (author's transl)].

Two different kinds of automatic dosage of urea in blood, the chemical with diacetyl monoxime and the enzymatic urea test Sclavo, are compared in order to verify the possibility of an utilization in screening on population. For such a purpose also the influence of different anti-coagulants is analyzed.


[Bacteriuria detection by dip-slide test (author's transl)].

A new dip-inoculum method markated as Microstix for detecting bacteriuria was studied to evaluate its usefulness as a screening procedure. This test was found to be reliable when compared with the standard pour plate method. However, antimicrobial agents often present in the urine samples rendered this procedure unsuitable for indiscriminate application in large hospital laboratories. This technique might conceivably be employed in mass screening programs where urine specimens are less likely contamined by antimicrobial drugs.


[Analysis of urinary calculi. Study methods].

A comparative study of the composition of a hundred urinary gravel stones is carried out, made by chemical analysis and spectroscopy infra-red. This research has shown that the spectroscopic method is better than chemical analysis: the latter method is excessively sensitive, above all when considering magnesium, phosphates and uric acid. The marked chemical disclosure of these substances takes us to false conclusions regarding the composition of the gravel stone with percentages varying between 20 and 40% of the cases. On the other hand chemical analysis has not revealed the presence of oxalates in 24% of the gravel stones examined. The spectroscopic method has shown itself to be simpler and faster to execute (a part from being more sensitive and precise), and capable of furnishing precise information on the composition of gravel stones, even very small ones of a weight of 500 microgram.


[A commercial available kit for semiquanititative determination of plasmatic and urinary aminoacids by thin layer chromatography (author's transl)].

A commercially available kit (Amino-acid TLC kit-Sibar, Perugia, Italy) for screening of plasma aminoacids inborn errors has been used as routine method for plasma newborn examinations in a mid-size clinical Laboratory. Good results were obtained by this inexpensive and simple kit.


The action of phosphocreatine and fructose 1,6-diphosphate on blood in vitro.

Blood in vitro has been used to evaluate the effects of phosphocreatine and fructose 1,6-diphosphate on the adenylate cycle. These compounds, following different metabolic pathways, increased the ATP concentration, phosphocreatine through a direct action on the adenylic phosphate cycle and fructose 1,6-diphosphate mainly by it glycolytic effect.


Biochemical changes in extracorporeal circulation in patients.

The effect of priming extracorporeal perfusion pumps with 50% and 80% diluted homologous blood on the serum electrolytes, acid-base status and plasma osmolality has been investigated in 103 patients undergoing open-heart surgery for congenital and acquired heart disease. The value in prognosis of plasma osmolality is discussed.


Burns caused by monitoring equipment during anaesthesia.

Hazards of monitoring during anaesthesia are burns, cardiac arrest or ventricular fibrillation, electric shock and false alarms caused by interference with the traces. The causative and contributory factors and the measures for the prevention of burns are discussed.


Artificial circulation for resuscitation after prolonged clinical death caused by hypoxia.

The dynamics of dying and the subsequent recovery of the main vital functions such as cardiac performance, respiration and unconditioned reflexes were investigated in 24 dogs resuscitated by Bryukhonenko's method of artificial circulation after 13-15 min clinical death caused by asphyxia. Application of artificial circulation during asystole required a gradual increase for 2-3 min in the volume of perfusion to optimum levels, since too rapid an increase of blood flow resulted in secondary ventricular fibrillation. In conditions of resuscitation with high volumes of extracorporeal perfusion (exceeding 100 ml kg-1 min-1), fast return of vital functions, their subsequent normalization, and relatively smooth recovery, can be achieved. Decreasing the rate of blood flow to 60-80 ml kg-1 min-1 delays the recovery of vital functions of the resuscitated organism. Severe post-resuscitation disease develops with a fatal outcome. Resuscitation with flows of 40 ml kg-1 min-1 or less is ineffective. We concluded that successful resuscitation after clinical death caused by asphyxia was possible only when the blood flow was 1.2-1.5 times higher than the normal cardiac output.


Plasma volume expansion after infusion of 5%, 20% and 25% albumin solutions in patients.

Fifty grams of albumin were infused into patients in the immediate post-operative period as either 5, 20 or 25% solutions. With all three solutions the increase in plasma volume was 500 ml or 11 ml/g of retained albumin, which is less than the normal water-binding capacity of albumin found in studies in vitro and in some clinical studies. This might be explained by a blocking of the water-binding capacity of the albumin or by the action of other unknown mechanisms, when albumin is given in an amount exceeding the losses. The expansion of the plasma volume did not depend on the concentration of the solutions given but only on the amount of albumin given and the deficit in plasma volume. Since albumin is a good plasma expander and a drug with a few secondary effects it is recommended in the treatment of shock. We prefer the 5% solution, which contains an electrolyte solution and is more easily infused, because of its low viscosity.


[Idiopathic orthostatic hypotension: Shy-Drager's syndrome (author's transl)].

The authors report a clinical case of idiopathic orthostatic hypotension with associated signs of focal cerebrovascular lesion. They discuss aetiopathologic hypotheses which have been proposed to interpret pathological situations of this type. It seems reasonable to attribute an autonomous disease classification to idiopathic orthostatic hypotension as a systemic degenerative disease concerning peripheral and central structures with vegetative functions. The Shy-Drager syndrome (idiopathic orthostatic hypotension associated with diverse signs of involvement of the central nervous system) must not, however, be considered as an independent form of disease. The associated signs are none other than the expression of commonly found cerebral ischemic lesions deriving from abrupt arterial hypotension, or from cerebral dysautoregulation; or the expression of the association of a systemic degenerative disease with another, a not infrequent occurrence well known in the pathology of the nervous system.


Tick-borne encephalitis (TBE) in Italy: report of the first clinical case.

Previous studies on the clinical features of meningoencephalitis in Italy did not help to indicate the nature of the causative agents. On the other hand during the past decade nine arboviruses were isolated in Italy, some of which are yet to prove pathogenic for man. A systematic study was carried out in cooperation between the Department of Neurology of the University of Florence and the Istituto Superiore di Sanità (Rome), in order to understand a possible role of arboviruses as etiologic agents of meningoencephalitis in Italy; in this preliminary communication the first clinical case of Tick-Borne Encephalitis (TBE) virus infection is described.


[Recording methods of intracranial pressure. (author's transl)].

The physiopathology of intracranial pressure and its measuring techniques are briefly discussed. Such measurements may be achieved: 1) At lumbar level (measurement of cerebrospinal fluid): the main limitations of this method are due to impossibility of long term recording and the danger of "cerebral erniation* in patients with increased ICP. 2) At cranial level with: a) ventricular catheter connected to a pressure transducer: its limitations are due to difficulties in entering small and/or displaced ventricules in case of cerebral edema or expanding lesion, danger of infections, and catheter obstruction amongst others. b) pressure transducer in the extradural space connected with external recorder by electric wires: its limitations are due to frequent lack of parallelism with the dural surface and the variability of correlations between extra and intradural pressure; c) subdural pressure transducer; these appear the most reliable both from the literature and from the Authors personal experience. The Authors stress the importance of ICP monitoring in head injuries and after intracranial surgery (mostly for an early detection of complications due to cerebral edema or hemorrhages).


[Subarachnoid haemorrhage from an ependymoma of the filum terminale. (author's transl)].

The case of a patient suffering from acute lumbosciatic pain, flaccid paraplegia, bladder retention and subarachnoid hemorrage, is reported. The patient underwent operation for a large ependymoma of the filum terminale. The author underlines the rare association of a spinal cord tumour and subarachnoid hemorrage and the opportunity of a routine mielo-radiculographic examination in case of lumbo-sciatic pain requiring surgical intervention: the patient, in fact, had been operated for "lumbar disc prolapse", in an orthopaedic department, four years before.


Asynchronous DNA replication and asymmetrical chromosome loss in Chinese hamster-mouse somatic cell hybrids.

A number of parameters were measured in a series of 12 hybrid cell clones from Chinese hamster and mouse cells to test the hypothesis that asymmetrical chromosome loss may result from asynchrony in the replication of the two parental sets of chromosomes. All clones tended to lose telocentric (mouse) chromosomes with culture time, irrespective of the starting ratio of parental chromosomes, and in all clones, biarmed (hamster) chromosomes appeared to complete DNA replication slightly earlier than telocentrics. However, no quantitative correlation could be established between the degree of asynchrony in chromosome DNA replication and the extent of chromosome loss. It appeared that telocentric chromosomes were lost more readily from those clones which started with a high hamster-to-mouse chromosome ratio.


Reactivation of chick erythrocyte nuclei in heterokaryons with temperature-sensitive Chinese hamster cells.

Chinese hamster cell line K12 is temperature-sensitive for the initiation of DNA synthesis. K12 cells synchronized by serum deprivation were collected in early G1(G0). Heterokaryons were formed by fusing chick erythrocytes with serum-starved K12 cells through the use of UV-irradiated Sendai virus. At the permissive temperature (36.5 degrees C), erythrocyte nuclei in heterokaryons enlarged, the chromatin dispersed, and erythrocyte nuclei synthesized DNA at about the same time as the K12 nuclei. At the restrictive temperature (41 degrees C), erythrocyte nuclei enlarged, but neither erythrocyte nor K12 nuclei initiated DNA synthesis. When erythrocyte nuclei were fused with Wg-1A cells, the wild-type parent for ts K12 cells, both kinds of nuclei synthesized DNA at 36.5 degrees C and 41 degrees C. Activation of erythrocyte nuclei was inefficient in heterokaryons incubated in low-serum medium. The results indicate that serum factors and a cellular function defined by the K12 mutation are required for activation of chick erythrocyte nuclear DNA synthesis.


Biochemical genetics of Chinese hamster cell mutants with deviant purine metabolism III. Isolation and characterization of a mutant unable to convert IMP to AMP.

The isolation and characterization of a new mutant of Chinese ovary cells (CHO-K1) is described. This mutant, Ade-H, has the following properties: (1) it forms a new genetic complementation group; (2) it specifically requires adenine for growth and will not grow on aminoimidazole carboxamide (AIC) or hypoxanthine; (3) it accumulates IMP; (4) it cannot synthesize adenine nucleotides; (5) its phenotype can be mimicked by treatment of CHO-K1 (the wild type parental strain) with hadacidin, an inhibitor of adenylosuccinate synthetase (E.C.6.3.4.4). Thus, the site of the defect in this mutant is presumed to involve the step in adenylate biosynthesis catalyzed by this enzyme. The usefulness of Ade-H for the study of regulation of purine biosynthesis in mammalian cells is discussed.


Cytogenetically marked clones in human fibroblasts cultured from normal subjects.

Clones of cytogenetically abnormal cells have been recognized in fibroblasts cultured from normal human adult skin. No such clones have been observed in human embryo skin fibroblasts cultured in the same way. Although the culture conditions may have played some part in the emergence of these clones, it is possible that the abnormal cells from which the clones were derived were present in vivo.


Nucleotide analysis of DNA and RNA in cells with thymidine totally replaced by bromodeoxyuridine.

The nucleotide composition of nuclear DNA has been determined in a cell line (HAB) that has grown for 275 generations with complete substitution of bromodeoxyuridine (BrdU) for thymidine in nuclear DNA. Within 50 generations there is a approximately 3% decrease in the G content and an equivalent increase in the BrdU content of DNA, relative to the unsubstituted parent cell line. However, these alterations do not continue to accumulate when the cells are grown for up to 275 generations with fully substituted DNA, suggesting that they are not brought about by BrdU-induced base transitions due to mispairing. RNA transcription has been examined both in vivo and in vitro to determine whether or not BrdU substitution in DNA results in large-scale transcriptional errors. The nucleotide composition of 18S and 28S rRNA from cells 0, 60%, and 100% substituted with BrdU does not significantly differ. Further, when DNA from these cells is transcribed in vitro with E. coli RNA polymerase, there is no evidence for altered incorporation of nucleotides into RNA made from the substituted templates.


Isolation and characterization of temperature-sensitive mutants of Chinese hamster ovary cells after treatment with UV and x-irradiation.

The isolation of ten conditionally lethal temperature-sensitive mutants of the Chinese hamster ovary cell (CHO-Kl, pro-) by the BUdR-visible light selection procedure described. Treatment with radiation at doses known to cause single gene mutation in mammalian cells increases the mutation frequency by a factor of at least 14. These mutants will grow with normal plating efficiency at 34.5 degrees but will not grow at 39.5 degrees. Complementation analysis by two independent methods indicates that all mutants are recessive and allows the assignment of the mutants to six genetically independent complementation groups. Reversion analysis indicates that the TS-mutants are stable, spontaneous revertants arising at a frequency of less than 10(-6). Preliminary chromosome analysis revealed no systematic chromasomal abnormality in the mutants. Mitotic accumulation is used to study the generation time of the parental cells and representative mutants at 34.5 degrees and 39.5 degrees. The uses of these mutants for genetic analysis of mammalian cells in culture is discussed.


Expression of human hypoxanthine phosphoribosyl transferase in Chinese hamster cells treated with isolated human chromosomes.

Chinese hamster cells deficient for the enzyme hypoxanthine phosphoribosyl transferase (HPRT) were incubated with isolated human metaphase chromosomes and 21 colonies were isolated in HAT medium. Three different types of cell lines were established from these clones. First, 4 cell lines had 10-30% of normal Chinese hamster HPRT activity with the same electrophoretic mobility as human HPRT. This HPRT activity remains detectable during at least 8 weeks of growth of the cells in nonselective medium. Second, 3 cell lines also had human-like HPRT with the same activity as the first type. This HPRT persists only if the cells are grown in HAT medium and disappears during 8 weeks of growth in nonselective medium. Third, other clones survived in HAT medium as well as in medium with 8-azaguanine. These cells had no detectable HPRT activity. Using differential chromosome staining techniques no recognizable human chromosome fragments were found in any of the cell lines.


Improved techniques for the induction of mammalian cell hybridization by polyethylene glycol.

Modifications in the techniques for the induction of mammalian somatic cell hybridization by polyethylene glycol (PEG) have led to procedures that are rapid, simple, and effective. The basic improvements, for both monolayer and suspension fusions, are a short exposure to PEG and a rapid dilution of PEG following treatment. There is a marked effect of PEG concentration on cell hybridization, and there seem to be inherent differences between cells in terms of the extent of cell fusion induced by PEG.


Assignment of the gene for cytoplasmic glutamic-oxaloacetic transaminase to the region q-24-qter of human chromosome 10.

Somatic cell hybrids between thymidine kinase-deficient mouse cells and human fibroblasts carrying a translocation of the distal third of the long arm of chromosome 10 to chromosome 17 were studied for the expression of cytoplasmic glutamic-oxaloacetic transaminase. A positive correlation between the expression of human cytoplasmic glutamic-oxaloacetic transaminase and the presence of the distal third of the long arm of chromosome 10 was established.


Differential staining of interspecific chromosomes in somatic cell hybrids by alkaline Giemsa stain.

Staining of chromosome preparations of Chinese hamster-human hybrid cells and mouse-chimpanzee hybrids with alkaline Giemsa has yielded color differentiation of the interspecific chromosomes. Bicolor chromosomes, indicating apparent translocations also are observed for each of these hybrids. The specific color differences observed provide a rapid means of recognizing and aiding in the identification of the interspecific chromosomes and apparent translocations in these somatic cell hybrids.


Biochemical selection systems for mammalian cells: the essential amino acids.

The essential amino acid requirement of cultured mammalian cells can be satisfied by 19 amino acid derivatives. This finding (a) confirms the results of animal nutritional studies and (b) identifies 19 essential amino acid derivatives and should permit the isolation of a new class of auxotrophic mutants. Five naturally occurring auxotrophic markers have been detected in this survey; namely, inability to utilize cystathionine and citrulline in Chinese hamster ovary (CHO) cells, inability to metabolize citrulline by HTC+hepatoma cells, and confirmation of Eagle's observation that KB cells can utilize homocystine in place of methionine or cystine and D-cystine in place of L-cystine.


Biochemical genetics of Chinese hamster cell mutants with deviant purine metabolism. IV. Isolation of a mutant which accumulates adenylosuccinic acid and succinylaminoimidazole carboxamide ribotide.

The production, isolation, and characterization of a new complementation group (Ade-I) of adenine-requiring mutant of Chinese hamster cells (CHO-K1) is described. This mutant accumulates two intermediates of purine biosynthesis, both of which contain an aspartate moiety. One of these is shown to be adenylosuccinic acid (AMPS) by chromatographic analysis, while evidence is presented that strongly suggests the other intermediate is succinylaminoimidazole carboxamide ribotide (SAICAR). Thus, Ade-I is most likely lacking the activity of the enzyme adenylosuccinase (EC 4.3.2.2). The use of this and similar mutants for the analysis of regulation of purine biosynthesis in mammalian cells is discussed.


Expression of transformation in cell hybrids. I. Isolation and application of density-inhibited Balb/3T3 cells deficient in hypoxanthine phosphoribosyltransferase and resistant to ouabain.

A cell line, THO2, was isolated from Balb/3T3 clone A31 after sequential nitrosoguanidine treatments and selection for resistance to 6-thioguanine and ouabain. THO2 retains the properties of density-dependent inhibition of growth and serum dependence of DNA synthesis characteristic of 3T3. The codominant expression of ouabain resistance and inability of THO2 to utilize exogenous hypoxanthine in the presence of aminopterin allows isolation of somatic cell hybrids involving THO2 and any ouabain-sensitive, hypoxanthine phosphoribosyltransferase-positive cell line. Hybrid clones derived from THO2 and SV40-transformed cells show dominant expression of the transformed phenotype with respect to multilayered arrangement of cells and ability to synthesize DNA in 1% calf-serum medium.


Human diploid fibroblast mutants with altered RNA polymerase II.

Clones resistant to the cytotoxic action of alpha-amanitin have been isolated from a strain of fetal human lung diploid fibroblasts. Resistant clones were recovered at a frequencey of 5 X 10(-8) after single-step selections following mutagenesis with the mutagen ethyl methane sulfonate. Following propagation in drug-free medium, the clones retained the selected phenotype and in both growth and plating experiments showed a 10-50-fold higher resistance than wild-type cells to the cytotoxicity of 0.25 microgram/ml alpha-amanitin. The alpha-amanitin sensitivity of RNA polymerase II purified from the mutant cells suggests the presence of two forms of the enzyme, one similar to that found in wild-type cells and a second form with increased resistance to alpha-amanitin inhibition. These results are consistent with previous evidence that alpha-amanitin resistance behaves as a codominant marker in mammalian cells.


Isolation of mutants lacking branched-chain amino acid transaminase.

Variants of the Chinese hamster ovary cell have been isolated which can no longer grow when valine, leucine, or isoleucine is replaced in the culture medium by its respective alpha-keto acid: alpha-ketoisovaleric acid, alpha-ketoisocaproic acid, or alpha-keto-beta-methylvaleric acid. These variants lack branched-chain amino acid transaminase activity. Evidence is presented indicating these variants to be single gene mutants. Genetic evidence is also presented confirming previous biochemical evidence that a single enzyme carries out transaminase functions on valine, leucine, and isoleucine. The branched-chain transaminase-deficient (trans-) mutants can be reverted to wild-type behavior by treatment with mutagenic agents. These mutants promise to be useful in exploring regulatory mechanisms in biochemical, genetic, and cancer research.


Isolation and partial characterization of three methotrexate-resistant phenotypes from Chinese hamster ovary cells.

Three mechanisms for resistance to methotrexate (Mtx) have been identified in Chinese hamster ovary (CHO) cells selected from resistance to this drug. First-step selections produce cells with either an apparent structural alteration in the enzyme dihydrofolate reductase (class I), or a decreased permeability to the drug (class II). Mutagenesis with ethyl methanesulfonate increases the proportion of Mtx-resistant cells 5-10-fold. Second-step selections to higher resistance using class I resistant cells as parents results in cells with an increased activity of the reductase enzyme (class III) with no apparent further qualitative alterations in the enzyme. All three classes of resistant cells retain their Mtx-resistant phenotype when cultured under nonselectivve conditions.


Dimethyl sulfoxide enhances polyethylene glycol-mediated somatic cell fusion.

The efficiency of fusion of human diploid cells by polyethylene glycol was greatly enhanced by addition of dimethyl sulfoxide. The extent of fusion was directly proportional to the concentrations of both of these compounds. At all except the highest concentrations, cell loss was moderate to minimal and perturbation of cell cycle function as measured by [3H] thymidine labeling indices and mitotic indices was minimal in the surviving cells. This technique is potentially useful for heterokaryon studies as well as for the isolation of hybrids of mammalian somatic cells.


Polyethylene glycol-induced mammalian cell hybridization: effect of polyethylene glycol molecular weight and concentration.

The effects of polyethylene glycol (PEG) molecular weight and concentration on mammalian cell hybridization were studied. The peak hybridization-inducing activity with all grades of PEG from 400-6000 was found to occur in the concentration range of 50-55%. However, changes in concentration were seen to have different quantitative effects with different grades of PEG. For monolayer fusions, PEG 1000 at 50% seems to be the optimal combination of PEG molecular weight and concentration, in terms of both efficiency of hybridization and relative insensitivity to dilution effects.


Contamination formed around a very narrow electron beam.

Specimen contamination in the electron microscope is studied in an attempt to clarify the processes involved in contamination deposition. A very narrow electron beam has been used to make small peaks of contamination on the surface of a thin carbon film. These peaks have been imaged and the rates of growth of the height, diameter and volume determined. It is concluded that a portion of the contamination can be related to the interaction of the electron beam with the adsorbed surface layer. Surface migration of adsorbed material is indicated as the supply mechanism. Significant deposition of material in regions not exposed to the beam is reported for the first time. A method for determining the thickness of thin amorphous carbon film in the range of a hundred to a few thousand Angströms is described.


Electronmicroscopic mass determination using photographic isodensity techniques.

Using Agfacontour, Kodalith, or similar films, it is possible to convert an electron micrograph into a map of regions of equal photographic density (isodensitites) by simple copying procedures. If images of polystyrene spheres  and a calibrated density wedge are included in the copies, it is possible to quantitatively calibrate the isodensities in terms of mass per unit area of the specimen. In this way, electronmicroscopic mass determination may be accomplished without the need of densitometers or other photometric equipment.


Direct phase determination for quasi-kinematical electron diffraction intensity data from organic microcrystals.

Direct phasing techniques using cosine estimates for three-phase and four-phase structure invariants in space group P1 are applied to zonal hk0 electron diffraction intensity data from an orthorhombic paraffin and a cephalin. Ab initio use of these kinematical phases is shown to derive the correct structures of the methylene subcell packings for these compounds in agreement with earlier determinations from Patterson maps.


Computer experiments for tilted beam dark-field imaging.

Simulated high resolution tilted beam dark-field electron micrographs for the conventional transmission microscope were obtained by performing wave optical calculations with a high speed computer. Various organometallic molecules and point defects in crystals were studied to assess whether the image structures resembled the orginal object in terms of atom positions and atom correlations for a variety of microscope conditions. For the organometallic molecules close agreement was found between actual experimental micrographs and calculated images for specific combinations of microscope parameters. The images of point defects indicate that it should be possible to identify these structures based upon image size and intensity which in turn are highly dependent on the strain field surrounding the defect.


Quantitative tensile-tilting stages for the high voltage electron microscope.

This paper describes a soft and a hard tensile stage for the high voltage electron microscope. Both stages can be combined with a top entry double tilting stage. The devices are driven by thermal expansion elements operating against water cooled parts. The drive mechanism shows smooth action with a relatively low response time and good long-time stability. The stages are equipped with strain gauge bridges for force and elongation measurements. The soft stage has a maximum load of 13 g, and a hard one reaches 1.5 kg.


The use of backscattered electrons for imaging purposes in a scanning electron microscope.

It is shown that the use of a very large detector for backscattered electrons can provide a signal comparable to that obtained in the secondary emission mode and that the resolution available is also comparable. A technique is described whereby the difference is taken between these two signals, and the use of this difference signal can significantly enhance surface details. It is believed that the use of such a signal should ultimately prove advantageous in increasing resolution.


The formation and interpretation of defect images from crystalline materials in a scanning transmission electron microscope.

The technique of scanning transmission electron microscopy (STEM) has been employed usefully in studies of amorphous materials, and the theory of image formation and interpretation in this case has been well developed. Less attention has been given to the practical and theoretical problems associated with the use of STEM for the examination of crystalline materials. In this case the contrast mechanisms are dominated by Bragg diffraction and so they are quite different from those occurring in amorphous substances. In this paper practical techniques for the observation and interpretation of contrast from defects in crystalline materials are discussed. It is shown that whilst images of defects are obtained readily under all typical STEM operating conditions, the form of the image and the information it contains varies with the angle subtended at the specimen by the detector. If this angle is too large significant image modifications relative to the "conventional" transmission electron microscope case may occur and the resolution of the image may degrade. If this angle is too small, then signal to noise considerations make an interpretation of the image difficult. In this paper we indicate how the detector angle may be chosen correctly, and also present techniques for setting up a STEM instrument for imaging a crystalline material containing lattice defects.


The extension of scanning transmission electron microscopy by use of diffraction information.

The information contained in the intensity distribution of the convergent beam electron diffraction pattern, produced in the detector plane for each incident beam position in a scanning transmission electron microscope, may be used to enhance the resolution of the microscope or else to decrease the electron irradiation of the specimen involved in deducing information at any particular level of resolution. The structural information concerning the specimen may be obtained, for example by interpretation of the Patterson function using image-seeking methods. The statistical error involved due to the finite number of electrons available may be derived by considering the efficiency of use of the information contained in Patterson function peaks. The most efficient means for using the available information appears to be that based on information theory concepts, which employ the integral over the product of the observed diffraction pattern intensity and the intensity calculated for known or postulated groupings of atoms. The reduction in radiation damage possible by use of this method, relative to that involved in the separate imaging of individual atoms, may be by a factor of approximately n, where n is the number of atoms in the known or postulated group being sought.


Very low voltage electron microscopy.

We conclude that a 150 V scanning microscope with a resolution of 10 A is quite feasible and could have considerable value. It might consist of a field emission source, an electron gun to decelerate the electrons, a condenser lens to produce a parallel beam, a multipole corrector and a short focal length objective lens. Electrons reflected from the specimen surface would pass through a spectrometer whose principal features would be a large collecting power and low (1/200) energy resolution. Finally, we should add that such a microscope presents a considerable challenge and new opportunities for the electron optician in both lens and spectrometer design. We cannot refrain from pointing out that the Scherzer theorem does not necessarily hold for such a lens since the constraints of the theorem do not apply to this case.


Use of pure carbon specimen holders for analytical electron microscopy of thin sections.

The use of a simple specimen holder, made of pure carbon, for analytical electron microscopy of sections of biological material is reported. Interference of the specimen holder with the X-ray spectrum from the specimen is minimized. The contribution of the holder to the continuum spectrum is consistent with theoretical predictions.


Use of coincidence techniques to improve the detection limits of electron spectroscopy in STEM.

A method of improving the detection limits of microanalysis using electron energy losses due to inner-shell excitation is proposed. This is based on coincidence detection of the energy-loss electrons with another signal which also results from inner-shell excitations, i.e., Auger electrons or characteristic X-rays. It is concluded that there will be a significant improvement in the detection of monolayers on a homogeneous monatomic substrate by using coincidence of energy-loss electrons with Auger electrons.


High resolution shadowing for electron microscopy by sputter deposition.

The sputtering process by an ion beam well collimated and highly accelerated provides a valuable means of high resolution shadowing, replication of a fine object by a combination of pre-shadowing and deposition as well as a preparation of supporting films. High resolution shadowing and films with grains smaller than 1 nm can be obtained by argon ion-sputtering targets of tungsten and tungsten/tantalum alloy. The resolution of carbon replicas pre-shadowed with tungsten/tantalum is determined from the radius of curvature of replicated magnesium oxide crystal corners.


Scanning transmission electron microscopy of thin specimens.

The intensity distributions in bright field and dark field images of thin specimens obtained in scanning transmission electron microscopy are evaluated in terms of the phase of object approximation for coherent and partially coherent illumination. Previous treatments, based on a weak phase object approximation are shown to contain unwarranted assumptions in some cases, resulting in predictions of limited validity. The probable errors due to the neglect of higher order terms in power series expansion and in the assumption that the dark-field signal from an annular detector is proportional to the total elastic scattering are evaluated. Questions of optimizing the signal intensity and contrast are examined by considering the detector configuration in relationship to the form of the convergent beam diffraction pattern formed in the detector plane and the implications for the use of diffraction pattern information to enhance the imaging process are considered.


The modification of the electron microscope for special crystallographic applications.

The conversion of the transmission electron microscope to a convergent-beam camera and shadow microscope with facilities for experiments using two specimens located in different planes is discussed, with particular reference to older models such as the Elmiskop 1. The conversion requires the removal of the intermediate lens in some microscopes and thus prevents them from operating in their original capacity. The Elmiskop 1 has a wide intermediate lens pole-piece which does not unduly restrict the diffraction angle. The smallest crystal spacing contributing to the convergent-beam diffraction pattern is 0.05 nm.


Radiation damage of proteins in the solid state: changes of amino acid composition in catalase.

Catalase has been irradiated with 100 keV electrons under conditions simulating the hazards of electron microscopic imaging. Amino acid analysis reveals a definite pattern of amino acid destruction which is well correlated with the particular chemical structures of amino acid side chains. This pattern appears to be distinctly different from the sensitivity pattern for monoamino acid systems, which fact is ascribed to intramolecular energy transfer and selective attack of liberated radicals.


Minimization of dose as a criterion for the selection of imaging modes in electron microscopy of amorphous specimens.

A fundamental limitation in electron microscopy of organic specimens is radiation damage by the electron beam. To minimize damage it is necessary to have maximum information collection for a given dose. Various modes of operation of conventional and scanning transmission microscopes are compared with respect to their ability to detect small changes in specimen thickness or density with a given signal to noise ratio. Incoherent imaging is assumed, and this is expected to apply to amorphous specimens under a variety of microscope conditions. For either very thin or very thick specimens, the scanning transmission microscope is found to require nearly 10 times less dose than a conventional microscope for the same signal to noise ratio in the image. For specimens of intermediate thickness, scanning and conventional transmission electron microscopes are roughly equivalent.


Influence of detector geometry on image properties of the STEM for thick objects.

Plural electron scattering within thick objects broadens and smoothes the intensity distribution in the detector plane of a scanning transmission electron microscope. Detector arrangements have been determined which give maximum contrast and optimum S/N when the object details are large compared to the scanning spot. Asymptotic expressions for the optimum detector angles, specimen resolution, and S/N were obtained which are valid for objects thicker than approximately four elastic mean free path lengths. Exact calculations of the changes in contrast and S/N with thickness fluctuations in amorphous carbon foils were performed for atbitrary foil thicknesses. Elastic and inelastic electron scattering was taken into account.


Contribution of electron energy loss spectroscopy to the development of analytical electron microscopy.

The combined use of an electron energy loss spectrometer and an electron microscope provides some chemical information at the nanometer scale. The physics of the interaction processes between the incident electron beam and the thin sample foil is reviewed in terms of energy and momentum transfer. This analysis of the content of an electron energy loss spectrum allows us to establish rules for a satisfactory use of the information and to discuss the detection limits of this newly developed microanalytical technique.


Estimation of the Ca2+ binding by microsomal membranes from pig coronary artery using a calcium ion selective electrode.

To estimate the Ca2+ binding of microsomal membranes from pig coronary artery a modified potentiometric method was used. With this method it was possible to follow directly changes in the Ca2+ ion activity of the incubation medium down to 10(-8) moles. Compared with the Ca45-filter technique the electrometrically measuring device built up was beside the obvious advantages of a directly indicating method more fast, simple and hightly sensitive.


[Insulin catabolism by transformed, cultivated mouse fibroblasts (L-cells)].

Cultivated, transformed mouse fibroblasts (L-cells) are endowed with enzyme systems for insulin breakdown that are comparable to those of many other types of non-dedifferentiated insulin target cells (time and substrate dependence, Km value). It cannot yet be decided, however, which of the potential enzyme systems (thiolproteindisulfide-oxidoreductase (TPO) [E.C. 1.8.4.2] or proteinase) is prevalent in insulin breakdown in intact L-cells. Despite the lack of typical target symptoms for insulin, the cultivated L-cell could provide an appropriate experimental model for the insulin metabolism.