Biomedical subjects
Publications and source records attributed to S Brand.
A case of toxic shock syndrome is reported in a patient with a gluteal abscess due to Staphylococcus aureus following an intramuscular depot-corticosteroid injection. The ensuing discussion covers the probable role of toxins and some therapeutic problems.
Albumin Redhill, a variant human albumin with the same C-terminal amino acid as albumin A but with arginine at the N-terminus has been isolated by chromatofocusing from the sera of an English family. Albumin Redhill appears to contain two sites of mutation in its protein chain and is probably a proalbumin. The ability of albumin Redhill to bind Ni(II) or Cu(II) ions is considerably less than that of albumin A.
Cytodifferentiation and synaptogenesis in the neostriatum (caudate nucleus and putamen) were analyzed by the Golgi impregnation method and electron microscopy in 14 fetuses and 8 postnatal rhesus monkeys. During the second fetal month the neostriatum consists primarily of simple, mostly bipolar, immature cells and a small number of undefined profiles ending with growth cones. The first morphologically defined synapses appear in the putamen at embryonic day 60 ( E60 ) and in the head of the caudate nucleus at E65 . Synaptic density in both structures is less than one per 1000/micron2 of neuropil at this stage; synapses are characterized by asymmetric junctions between axonal profiles and immature dendritic shafts, accumulation of an intermembrane web and aggregation of round clear vesicles in presynaptic profiles. During the third fetal month neuronal cell bodies and glial cells enlarge, and axonal and dendritic processes in Golgi preparations become more complex. Although the basic morphology of synapses remains unchanged, their density increases to 9/1000 micron2 in the putamen and 3.7/1000 micron2 in the caudate. During the fourth fetal month the four principal cell classes of the neostriatum emerge. Spines on the shafts of dendrites are followed closely by the appearance of axospinous synapses. Synaptic density in the putamen is still significantly higher (10.1/1000 micron2) than in the caudate (5.4/1000 micron2), but by the end of the fifth fetal month ( E150 ) it is the same (80/1000 micron2) in both structures. A dramatic increase in synaptic density to 125/1000 micron2 occurs before term ( E165 ) with the emergence of the first asymmetric synapses as well as symmetric synapses with flat or pleomorphic vesicles that terminate predominately on dendritic shafts. Synaptic density continues to increase after birth, reaching a plateau of approximately 190/1000 micron2 at the end of the first postnatal month. Throughout postnatal development the proportions of symmetric and asymmetric synapses on the smooth dendritic shafts undergo systematic fluctuations which may reflect the ingrowth of various afferents as well as local cytological differentiation including the formation of cellular compartments.
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The cellular composition of the primate claustrum was analyzed using serially sectioned Golgi impregnated neurons. The tissue used in this study was embedded in a soft resin mixture and cut with 25 mm long glass knives. The resin embedding allowed the sections to be cut serially at a thickness of only 3 micrometers. A camera lucida was employed for drawing the cellular processes from selected impregnated neurons; these drawings were later incorporated into a single composite picture of the neuron. Three types of neurons were observed in the primate claustrum. The largest of these neurons (Type 1) had a cell body and spine-laden dendritic arborization that varied in size and shape according to the neuron's position in the claustrum. The axons of Type I neurons were successfully impregnated in 25-day-old animals and were found to form collaterals within the claustrum. The collaterals from the axons of these cells appeared to leave the claustrum through both the external and extreme capsules. A second neuron found in the claustrum (Type II) had a round cell body with smooth beaded dendrites which radiated in all directions. The axon of the Type II neuron appeared to give off numerous collaterals that were not observed to leave the claustrum. A third type of neuron (Type III) had a small pear shaped cell body and a sparse dendritic tree. The axon and its collaterals appeared to remain within the dendritic circumference of the Type III neuron.
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In the cat neostriatum the histochemical distribution of acetylcholinesterase (AChE) was compared with the autoradiographic localization of the cholinergic muscarinic antagonist [3-(3)H]quinuclidinyl benzilate ( [3H]QNB). While the AChE was found to be localized in a pattern of AChE dense and sparse zones the muscarinic receptors were distributed evenly throughout the neostriatum. The results suggest that the AChE histochemical patches in the neostriatum are not indicative of the distribution of cholinergic synapses.
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With the use of Golgi, horseradish peroxidase, and electron microscopic techniques, neurons within a broad region of the preoptic hypothalamus of the mouse were shown to have dendrites that projected well into the depths of the optic chiasm. Further experimental and ultrastructural investigation demonstrated synapses between these dendrites and retinal axonal boutons within the chiasm. All synapses located in the chiasm were classified as Gray's type I. The possible function of these dendritic projections is discussed.
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Young and adult cats were operated upon and a number of the vermal cerebellar folia were either transected with a vertical incision or isolated by a horizontal cut. In the proximity of the lesion, Purkinje cell bodies and their dendritic trees became stainable with the Fink-Heimer method. Electron microscopy of the silver stained sections show that the argyrophilic Purkinje neurons undergo an electron dense type of degeneration. Stellate cell dendrites adjacent to the degenerating Purkinje trees are normal, suggesting that the cause of cell death is axotomy close to the perikaryon rather than direct injury. The retrograde Purkinje cell degeneration is fulminant since it is evident 6 hours after the lesion. In Fink-Heimer stained sections the entire dendritic tree is impregnated 1-3 days after the lesion. 4-10 days post-operatively, the flattened dendritic tree becomes fragmented and is partially phagocytized. The silver stained arborizations are approximately 280 mu in width and have an uneven thickness (8-16 mu). In longitudinal and horizontal silver stained sections of lesioned cerebellar folia, uninterrupted fields of degenerating Purkinje cell arborizations can be seen, suggesting that the arborizations overlap. The overlap was demonstrated in electron micrographs of single degenerating arborizations surrounded by normal dendritic trees. The degree of overlap varies with the thickness of the arborization and is in the order of 1-2 mu. This approach indicates that each Purkinje tree occupies an exclusive sheet of molecular layer 8 mu thick and may overlap for as much as 2 mu on each side with neighboring trees. The average thickness of the Purkinje tree is approximately 12 mu.
Experimental light and electron microscopic studies were carried out to determine the length of parallel fibers in the cat cerebellar cortex. Using a fine surgical knife, vermal and hemispheral folia were cut perpendicular to their long axis. The animals were sacrificed 1-10 days after the operation. Sections of the transected folia were then stained with a Fink-Heimer procedure. The resulting degeneration appeared as fine dots that extended lateral to the lesion, as predictable from the course of the parallel fibers. Densitometer readings indicate that the density of degeneration declines gradually lateral to the lesion. The specificity of the silver impregnation was checked by processing silver stained sections for electron microscopy. This confirmed the location of the silver precipitate on degenerating parallel fibers. The pattern of parallel fiber degeneration in the molecular layer has a trapezoidal configuration centered on the lesion. The shorter parallel fibers are located at the base of the molecular layer and extend for 5 mm. The parallel fibers become progressively longer as they approach the pial surface where they attain a maximum length of 7 mm. Our studies suggest that in folia longer than 7 mm parallel fibers are 6 mm long on the average. In addition, it was determined on Golgi sections that the average center-to-center distance between en passant boutons of individual parallel fibers is 5.2 mum. The data indicate that an average parallel fiber, 6 mm long, forming approximately 1100 boutons, may synapse with each Purkinje dendritic tree it traverses.
Papain is a proteolytic enzyme widely used by biochemists. In experiments on animals papain has been shown to cause emphysema either when they inhaled a single small dose or after intratracheal inhalation. Four food technologists were occupationally exposed to heavy concentrations of papain dust in air. Subjects 1 and 2 developed an immediate acute asthmatic reaction, and symptoms of obstructive airways disease persisted for some months while each remained in the same working area, presumably exposed to small gradually diminishing amounts of residual papain dust. Tests of respiratory function were carried out on all four subjects 1 1/2 years later and showed in subjects 1 and 3 minimal abnormality of bronchial reactivity and of ventilation distribution. Review of the literature reveals only two reports of asthma resulting from papain inhalation, although its antigenic and skin sensitizing qualities have been known and described for many years. It seems remarkable that a substance such as papain, shown to be a potent cause of lung damage in experimental animals, should have produced so little evidence of abnormality in our subjects after considerable exposure. Follow-up ventilatory function tests may cast further light on this but we postulate that the asthmatic response may be biologically protective and those lacking this reaction could later develop emphysema as a long-term outcome.
The writer used self-recording and charting of his own behavior as a way to observe and manage changes during his senior year at high school. The method used has implications for the application of behavior modification technology to self-management, and to behaviors that occur inside an organism's skin. The results have implications for study of the Senior Slump", for college and career planning in high school, for clarifying interpersonal attitudes, and for keeping track of one's emotional well-being.
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Like so many aspects of nursing, diabetes care has changed over the years. This article will look at the condition of diabetes mellitus and its implications for care and examine some of the relevant physiological mechanisms, also in relation to care.