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Biomedical subjects

E Frank

Publications and source records attributed to E Frank.

At least 415 records · Page 23Linked to original sources
PubMed1982

Basilar impression and platybasia in osteogenesis imperfecta tarda.

Osteogenesis imperfecta, a rare, genetically transmitted disorder of bone, is known to be associated with the development of basilar impression and platybasia. These deformities of the base of the skull may cause neurosurgical abnormalities secondary to compression of the brainstem and hydrocephalus. The case is presented of a young boy with a family history of osteogenesis imperfecta tarda who suffered respiratory arrest during hospitalization. Cranial nerves and pyramidal tract signs were demonstrated. Roentgenograms showed severe basilar impression and hydrocephalus. Decompression of the brainstem and shunting were performed with improvement in the patient's neurological status. This case represents a rare by significant central nervous system complication of osteogenesis imperfecta. Early recognition and implementation of aggressive treatment are important if irreversible neurological deficits are to be avoided.

Adolescent↗
PubMed1982

Synaptic organization of sensory and motor neurones innervating triceps brachii muscles in the bullfrog.

1. The anatomy and physiology of sensory-motor pathways were studied in the brachial spinal cord of adult bullfrogs to characterize the properties and specificity of these connexions.2. Motoneurones innervating a given forelimb muscle are located in discrete and reproducible regions of the lateral motor column. Yet only a fraction of the motoneurones in a particular region innervates any one muscle.3. The central projections of sensory afferent axons from the triceps muscles extend throughout the rostro-caudal length of the brachial spinal cord. Within this region these projections terminate in an area containing many motoneuronal dendrites.4. Within the triceps motor pool sensory neurones from the triceps muscles produce monosynaptic potentials only in triceps motoneurones even though these motoneurones are mingled with motoneurones innervating other muscles.5. Motoneurones innervating each of the three heads of the triceps muscles, medial, internal and external, receive monosynaptic input from their own, homonymous muscle head. Sensory fibres from the medial head also innervate 98% of the heteronymous motoneurones projecting to the internal or external heads, and nearly 90% of the medial triceps motoneurones are innervated by sensory axons from the other two heads.6. Similarly, other brachial motoneurones receive monosynaptic input from sensory axons in their own muscle nerves. However, most of the synaptic potentials evoked in triceps motoneurones by stimulation of muscle nerves other than triceps are of longer latency and probably involve polysynaptic pathways.7. Thus, the pattern of synaptic connexions between muscle sensory afferents and motoneurones in the frog's spinal cord is specific. Furthermore, comparison with homologous pathways in the cat's spinal cord suggests that the strength and pattern of these connexions are similar.

Afferent Pathways↗
PubMed1982

The formation of appropriate central and peripheral connexions by foreign sensory neurones of the bullfrog.

1. The ability of foreign sensory neurones to form novel reflex pathways was studied in bullfrogs by removing, during early larval stages of development, the dorsal root ganglion (d.r.g. 2) that normally provides the entire sensory innervation of the front limb.2. After the operation these tadpoles metamorphosed into frogs that responded to sensory stimuli and had nearly normal use of the limb. Sensation in the limb was mediated by sensory neurones located in an adjacent ganglion (d.r.g. 3); these neurones normally never grow into the arm.3. These neurones were shown, by labelling with horseradish peroxidase, to project into the arm and into the region of the brachial spinal cord occupied by motoneurones innervating muscles in the arm. These projections do not occur at any time during normal development.4. Intracellular recordings from identified motoneurones demonstrated that when the operations were done before developmental stage 9 appropriate monosynaptic sensory-motor pathways were established. The relative strengths of synergistic and antagonistic sensory projections onto motoneurones were normal, although the latencies of the synaptic potentials were somewhat longer.5. When the operation was performed after stage 9 but before metamorphosis, d.r.g. 3 sensory afferents grew into the arm and into the brachial spinal cord but did not make monosynaptic connexions onto motoneurones.6. Removal of d.r.g. 2 from adult bullfrogs failed to produce either central or peripheral changes in the projections of d.r.g. 3 sensory neurones.7. Many d.r.g. 3 neurones still innervated their normal sensory targets in the thorax. These neurones never formed monosynaptic connexions onto brachial motoneurones in either normal or experimental animals. In experimental animals, the polysynaptic projections of these third nerve sensory neurones to brachial motoneurones were stronger than in normal animals independent of when d.r.g. 2 was removed during development.8. Thus foreign sensory cells can form specific, functionally appropriate connexions between peripheral targets and motoneurones if the sensory cells that normally mediate this reflex pathway are removed sufficiently early during development.

Afferent Pathways↗
PubMed1982

Specificity of electrical coupling among neurons innervating forelimb muscles of the adult bullfrog.

1. The specificity of electrical connections among sensory fibers and motoneurons in the bullfrog's spinal cord was studied by recording intracellularly from brachial motoneurons. Synaptic potentials evoked by stimulation of individual muscle nerves were recorded in normal and reduced-calcium solutions and after acute section of dorsal or ventral roots. 2. Homonymous motoneurons are electrically coupled. After the dorsal roots were cut to abolish sensory input, short-latency potentials were almost always evoked anti-dromically in a motoneuron by stimulation of its own muscle nerve but rarely by stimulation of nerves innervating other muscles. These potentials differed from chemically mediated synaptic potentials in this preparation; they had a shorter latency and remained after perfusion with reduced-calcium solutions. This evidence suggests that they are mediated electrically. 3. Some motoneurons that innervate functionally equivalent muscles are electrically coupled. Approximately two-thirds of the motoneurons innervating the internal or external heads of the triceps muscles received coupling potentials on stimulation of the other nerve, although never on stimulation of the heteronymous, medial, triceps nerve. 4. The monosynaptic potentials evoked by muscle sensory afferents in motoneurons often have both electrical and chemical components. The electrical component occurred with short delay and persisted in reduced-calcium solutions. The chemical component occurred 1.5-2.0 ms later, at 14 degrees C, and was abolished by reducing calcium in the bathing solution. Muscle sensory afferents make these mixed synapses on homonymous, heteronymous, and other motoneurons.

Animals↗
PubMed1981

The prolonged Q-T syndrome presenting as a focal neurological lesion.

A patient with a prolonged electrocardiographic Q-T interval suddenly developed left hemiplegia after an episode of ventricular fibrillation. A CT scan showed a cerebral infarction in the right internal capsule. The prolonged Q-T interval, by virtue of its association with cardiac arrhythmias, may cause cerebral hypoperfusion that commonly results in generalized neurological deficits. The lack of evidence for embolization in this patient suggests that decreased cerebral perfusion was responsible for the genesis of her neurological signs and symptoms. The prolonged Q-T interval is an easily overlooked cardiac abnormality that must be considered in a patient who exhibits a focal neurological deficit.

Adult↗
PubMed1981

Coping with sudden blindness.

The case of a college student totally blinded in an accidental shooting who achieved a remarkably rapid and effective adjustment presented a rare opportunity to study the adaptive capacity of a previously well adjusted person to sudden disaster. Important factors included the patient's extroverted, optimistic personality, the support of a cohesive family, strongly united by shared beliefs and values, the hospital staff's unequivocal acknowledgment of the irreversibility of the injury, and immediate involvement of the rehabilitation counselor. The ability to find meaning and purpose in adversity, shared by successfully rehabilitated prisoners of war or war-injured soldiers and by survivors of concentration camps, appeared to be the most crucial factor of all in the readjustment process.

Adaptation, Psychological↗
PubMed1981

A comparison of nonpatient and bipolar patient-well spouse couples.

The authors compared responses of 16 couples, in which one partner had a diagnosis of remitted bipolar illness, to a lengthy self-report questionnaire (KDS-15) designed to assess many aspects of marital adjustment with those of 16 matched nonpatient couples. The bipolar patient-well spouse couples had marital adjustments closely resembling those of the nonpatient couples; three of four global ratings of satisfaction failed to discriminate between the two groups. Perceptions of the courtship, first year of marriage, and the degree to which the marriage had met expectations were also similar for both groups.

Adjustment Disorders↗
PubMed1981

Expression of influenza A virus internal antigens on the surface of infected P815 cells.

A panel of hybridoma antibodies was used to study the expression of the 2 major internal influenza A virus proteins, matrix protein (M), and nucleoprotein (NP) on the surface of influenza A-infected P815 cells. Using a sensitive radioimmunoassay (RIA) performed with live infected P815 cells only minute amounts of M were detectable, whereas M was not detected in 3 other cell-surface assays. In contrast, NP was detected in 10-fold greater amounts than M and 10- to 50-fold lower amounts than the viral glycoproteins by RIA. Furthermore, the presence of NP could be demonstrated by immunofluorescence, microcytotoxicity, and agglutination assays performed on live infected cells.

Adsorption↗
PubMed1980

Lysophosphatidyl choline facilitates labeling of CNS projections with horseradish peroxidase.

Previously, it has been difficult to label sensory terminations in the CNS by back-filling peripheral sensory nerves with horseradish peroxidase (HRP), apparently because the amount of HRP transported along the axons is insufficient. Labeling of central sensory projections in axolotls and frogs can be improved by agents known to disrupt membranes. Of those tested, L-alpha-lysophosphatidyl choline is the most effective. The addition of this detergent ot the HRP solution dramatically increases both the number of axons labeled and the density of label within single axons.

Ambystoma↗
PubMed1979

Streptococcal endocarditis (nonenterococcal, non-group A): single vs combination therapy.

A 14-year experience with streptococcal endocarditis was reviewed. The effect of single vs combination antibiotic therapy on the relapse rate was found to be comparable. Of 68 patients treated, four patients died during therapy. Two of 46 patients receiving single-agent and none of 18 patients receiving combination therapy experienced a relapse. Duration of symptoms before diagnosis was the main risk factor predisposing to relapse, which occurred in two of 13 patients with symptoms for longer than three months and in none of 51 patients with symptoms for three months or less before diagnosis. Combination therapy offered no advantage over a single agent in the latter group. Optimal therapy for patients with symptoms for longer than three months could not be determined in this study. However, no relapses were observed in this high-risk group when a single agent was given for longer than 21 days.

Adult↗
PubMed1979

Depressive symptoms in rape victims.

Thirty-four recent rape victims were assessed for depressive symptomatology using a well-validated self-report instrument in combination with formal psychiatric evaluation. Fifteen subjects were found to be moderately or severely depressed when measured on the self-report questionnaire. A closer examination of these 15 subjects revealed that 8 were suffering from a major depressive disorder. The authors emphasize that all clinicians working with rape victims should be alert to the emergence of depression in this population.

Adolescent↗
PubMed1979

Early events in neuromuscular junction formation in vitro: induction of acetylcholine receptor clusters in the postsynaptic membrane and morphology of newly formed synapses.

The development of clusters of acetylcholine (ACh) receptors at newly formed synapses between embryonic chick spinal cord and muscle cells grown in vitro has been studied by iontophoretic mapping with ACh. A semi-automated technique using on-line computer analysis of ACh responses and a photographic system to record the position of each ACh application permit the rapid construction of extensive and detailed maps of ACh sensitivity. Clusters of receptors, evident as peaks of ACh sensitivity, are present on many uninnervated myotubes. The distribution of ACh sensitivity closely parallels the distribution of 125I-alpha-bungarotoxin binding sites on the same muscle cell. In all cases where individual myotubes were adequately mapped before and after synapse formation, ingrowing axons induced new clusters of receptors rather than seeking out preexisting clusters. Synapses can form at active growth cones within 3 h of nerve-muscle contact. New receptor clusters can appear beneath neurites within a few hours. Many of the uninnervated clusters on innervated myotubes disappear with time. In contrast, receptor clusters on uninnervated myotubes remain in the same location for many hours. Synaptic clusters and clusters on uninervated myotubes are stable even though individual receptors are metabolized rapidly. The morphology of several identified sites of transmitter release was examined. At the scanning EM level, synapses appeared as small, rough-surfaced varicosities with filopodia that radiated outwards over the muscle surface. One synapse was studied by transmission EM. Acetylcholinesterase and a basement lamina were present within the synaptic cleft.

Animals↗
PubMed1978

Frequency of sexual dysfunction in "normal" couples.

In analyzing the responses of 100 predominantly white, well educated and happily married couples to a self-report questionnaire, this study examined the frequency of sexual problems experienced and the relations of those problems to sexual satisfaction. Although over 80 per cent of the couples reported that their marital and sexual relations were happy and satisfying, 40 per cent of the men reported erectile or ejaculatory dysfunction, and 63 per cent of the women reported arousal or orgasmic dysfunction. In addition, 50 per cent of the men and 77 per cent of the women reported difficulty that was not dysfunctional in nature (e.g., lack of interest or inability to relax). The number of "difficulties" reported was more strongly and consistently related to overall sexual dissatisfaction than the number of "dysfunctions."

Adult↗
PubMed1978

Accumulation of acetylcholine receptors and acetylcholinesterase at newly formed nerve-muscle synapses.

Nerve-muscle synapses form and the postsynaptic membrane begins to differentiate rapidly in vitro. New clusters of AChRs have been located at transmitting synapses within 3 hours after a competent neurite contacted a receptive myotube. Receptors within new subneural clusters are not identical with receptors at adult end-plates: they are metabolized rapidly and their mean channel open time is prolonged. In this sense synapse formation must be considered a drawn out affair. AChE also accumulates at synapses soon after functional contacts are established. The cleft enzyme is apparently regulated differently than receptors in the postsynaptic membrane. Muscle activity is necessary for the early accumulation of AChE, but not for the clustering of receptors. Further studies in vitro should be useful for analysis of the role of muscle activity, of the local neural influence on the postsynaptic membrane, and of the mechanism of the muscle response.

Acetylcholine↗
PubMed1977

[Development of refraction and visual acuity of squinting children (author's transl)].

The refraction and visual acuity rates of 170 children from the age of 2 to the age of 7 suffering from squint were recorded and analysed. On the basis of our investigation we could not prove the process of emmetropisation during the growth of the eyes of squinting children in this age group. That means that the process of emmetropisation of squinting children takes place slower and later than with non-squinting children and is apparently stabilized at an age between 8 and 12 years. On the other hand--the increase of visual acuity of the normal eyes of squinting children is--as a rule-completed at the age of 5, like that of non squinting children.

Age Factors↗