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Showing papers by "University of Texas Medical Branch published in 1971"


Journal ArticleDOI
TL;DR: The dorsal funiculus in cervical spinal cords of rats from 3 to 120 days postnatal was studied in order to document and quantitate glial cell development and axonal growth as related to the initiation and progress of central myelination.
Abstract: The dorsal funiculus in cervical spinal cords of rats from 3 to 120 days postnatal was studied in order to document and quantitate glial cell development and axonal growth as related to the initiation and progress of central myelination. Within the dorsal funiculus are three major and distinct tracts, each having distinct developmental trends and adult characteristics in terms of fiber sizes and amount of myelin. These tracts are the cuneate and gracile fasciculi and the cortico-spinal tracts. Glial cell counts and cross-sectional surface area determinations of each tract at increasing ages show that the initial rate of glial population increase is similar. However, each tract is unique in terms of the age at which a maximum population density is reached and the rate at which the expected population dilution takes place. An electron-microscopic examination indicates that oligodendrocytes constitute over 85% of the total glial population throughout the development period surveyed. As such, these cells are primarily responsible for the population density changes. The diameters of unmyelixgnated fibers, promyelin fibers and some myelinated fibers in these tracts were measured at 5, 10, 15, 20 and 120 days postnatal. This was done both for the purpose of relating glial population density changes with the initiation and decline of active myelination, and for determining whether or not a critical diameter for myelination exists in the CNS as was found in peripheral nerves (Matthews, '68). For each tract there is a characteristic sequence of events involving not only myelination, but also changes in diameter distribution just prior to the appearance of myelin and during the period of active myelin formation. These events coincide with the concentration and dilution of the glial population, but it is also evident that there is no critical and constant diameter in the CNS above which all axons are myelinated and below which all are unmyelinated. Myelin appears first on larger axons, but as the animal matures, it is found on progressively smaller axons until between 20 and 120 days, axons 0.2–0.4 μ in diameter acquire myelin. Thus, myelination begins with axons destined to be large and then extends down to those which enlarge very little prior to acquiring myelin and remain very small even in adult animals. Finally, from the determination, in adult rats, of the number of axons and oligodendrocytes in a defined volume of each tract and an estimation of internode length, the ratio of internodes to oligodendrocytes was calculated. The specific values obtained could vary by as much as ±50% and are only meant to serve as indicators of a trend. However, it is suggested that the number of internodes per oligodendrocyte may be inversely proportional to the length of the internode.

225 citations



Journal ArticleDOI
TL;DR: The retina is recommended for studies of synaptogenesis in tissue culture, for it offers several advantages over expiants from other areas of the neuraxis, including a clear layering pattern, many identifiable cell processes with characteristic synaptic relationships between them, and a well-defined sequence of developmental events.
Abstract: Retinae from two- and three-day-old rats were explanted in plasma clots and grown in vitro with the flying coverslip method. After seven to seventeen days in culture, the retinal tissue was fixed with aldehydes and osmium tetroxide and embedded for examination with the electron microscope. Study of cross sections (perpendicular to the coverslip) revealed a histotypic pattern of organization, especially in the thicker regions of the explants. Layering of cells quite similar to that in the intact retina was seen to develop from the relatively primitive, explanted retinal epithelium. However, each layer contained fewer cells than its counterpart in vivo. All major neuronal cell types were distinguished by their location and cytological characteristics. Development of the saccules of sensory cell outer segments was observed to occur in vitro by an infolding of the plasma membrane. Synaptic ribbon complexes developed to the mature form in the outer plexiform layers, while conventional synapses were numerous in the inner plexiform layers. Synaptic ribbons were also seen in bipolar cell axons in the inner plexiform layers. Amacrine and ganglion cells in these regions were relatively sparse. A survey of posterior regions of noncultured three-day-old rat retinae showed no synapses of any sort; therefore the synapses in the cultures formed in vitro. The retina is recommended for studies of synaptogenesis in tissue culture, for it offers several advantages over expiants from other areas of the neuraxis, including a clear layering pattern, many identifiable cell processes with characteristic synaptic relationships between them, and a well-defined sequence of developmental events.

79 citations


Journal ArticleDOI
TL;DR: Thirty-one cases in a series of 127 cases operated on by the Lincoff technique for retinal detachment surgery required removal of the silicone sponge implants, suggesting mechanical factors affecting the implant are primarily responsible for sponge rejection in these late cases.
Abstract: Thirty-one cases in a series of 127 cases operated on by the Lincoff technique for retinal detachment surgery required removal of the silicone sponge implants. Sponge rejection or infection can be divided into two distinct categories: Early and late. Nine cases were classified early and required removal of the sponge within the first eight weeks following surgery. These cases were a result of contamination at the time of surgery or in the immediate postoperative period. Twenty-three cases required sponge removal between two months and four years following surgery. We believe that mechanical factors affecting the implant are primarily responsible for sponge rejection in these late cases and that infection and foreign body reaction play only a secondary role.

73 citations


Journal ArticleDOI
09 Jul 1971-Science
TL;DR: The urinary activities for bone marrow colony formation were measured on consecutive 24-hour urine samples from two gray collie dogs with cyclic neutropenia and from two normal collies, suggesting a regulatory hormonal role for the substance measured by this assay.
Abstract: The urinary activities for bone marrow colony formation were measured on consecutive 24-hour urine samples from two gray collie dogs with cyclic neutropenia and from two normal collies. The activity varied cyclically in the gray collies with a peak activity developing during the neutropenic phase, which antecedes the return of blood neutrophils. The activity fell to undetectable levels after the blood neutrophil counts returned to the normal range. The urine of normal dogs showed no activity. Since the dogs with cyclic neutropenia have been shown to have periodic hematopoiesis, these data suggest a regulatory hormonal role for the substance measured by this assay.

72 citations


Journal ArticleDOI
TL;DR: In this article, the authors used Depot medroxyprogesterone acetate (DMPA), 150 mg. every 3 months, followed through 14,000 months of use as a contraceptive.

52 citations


Journal ArticleDOI
TL;DR: It is concluded that hypertrophic scars contain more glycoprotein and mucopolysaccharide and are more active metabolically.
Abstract: SummaryA study of the hexose hexosamine, sialic acid, uronic acid, glycogen, and collagen fractions has been made on hypertrophic scars, nonhypertrophic scars, and normal skin. Hexose, hexosamine, sialic acid, uronic acid, and glycogen levels were significantly and consistently elevated in hypertrophic scars. These same components were slightly, but significantly, higher in the nonhypertrophic scars. Salt-soluble collagen of hypertrophic scars was significantly elevated, citrate-soluble and insoluble collagen fractions were not different in the three groups. From these data it is concluded that hypertrophic scars contain more glycoprotein and mucopolysaccharide and are more active metabolically.

45 citations


Journal ArticleDOI
01 Dec 1971-Blood
TL;DR: Headache, fever, and/or vomiting occurred in 38% of the children after one or more of the intrathecal maintenance treatments and, in general, symptoms tended to worsen as maintenance continued.

43 citations


Journal ArticleDOI
TL;DR: This treatment resulted in inhibition of compensatory ovarian hypertrophy (COH) that was comparable to the antigonadotropic effects of 30.0 μg of crystalline melatonin injected in the same manner.

43 citations


Journal ArticleDOI
TL;DR: Under conditions of intravenous infusion, the plasma amino acid specific activity is maintained constant after a period of about 1 h, and it is calculated that protein catabolism in the normal fed rats contributes approx.

39 citations


Journal ArticleDOI
TL;DR: A case of sphenoid fissure syndrome in which occlusion of the superior ophthalmic vein was demon­ strated by orbital venography is described.

Journal ArticleDOI
TL;DR: Investigation of the external potential field along the functionally isolated medullated giant fiber of the shrimp revealed the absence of a myelin sheath, and impulse conduction appears to be saltatory, and these excitable areas function as nodes of Ranvier.
Abstract: The external potential field along the functionally isolated medullated giant fiber of the shrimp (Penaeus setiferus) was recorded during impulse conduction using 1 M NaCl-filled glass capillary electrodes. The giant fiber displays no nodes of Ranvier, yet shows a conduction velocity greater than 90m/second at 20°C. Recordings from most parts of the myelin-covered giant fiber surface showed only small monophasic positive potentials. However, at the areas of giant fiber-motor giant fiber synapses and where giant fiber axons branch into abdominal ganglia, a small positivity was followed by a negativity (sink of the action current). The local application of action potential depressants to these areas abolished the negativity and converted it into positivity, and consequently impulse conduction was blocked. Application of the action potential depressants to other areas of the giant fiber did not block impulse conduction. The sink of the action current was not found from the axolemma in the myelin cylinder; this part of the axolemma together with the low resistance gap fluid simply serves as a passive current conductor. Light and electron microscopic studies of the two functionally excitable areas revealed the absence of a myelin sheath in some small areas of both regions. Thus, impulse conduction appears to be saltatory, and these excitable areas function as nodes of Ranvier.

Journal ArticleDOI
TL;DR: These lymphocytes exhibited a bipolar structure with a regional distribution of cytoplasmic organelles and a difference between the structural features of the interaction of the two poles of the motile lymphocyte with the macrophage are discussed in relation to the regionalization of functions within the motiles lymphocyte.


Journal ArticleDOI
TL;DR: Polyphloretin phosphate administered to two rabbits in a cumulative dose of 94 mg/kg showed no significant blocking action on the vasodepressor or uterine and oviduct contractor responses to PGE1 or PGF2α though this compound, like meclofenamic acid, has been reported to antagonize the actions of PGE2α on isolated smooth muscle preparations.
Abstract: 1. The prostaglandin-blocking activity of meclofenamic acid, N-(2,6-dichloro-m-tolyl)anthranilic acid (CI-583), was analysed in the anaesthetized rabbit. PGF(2alpha), PGE(1) and isoprenaline were injected before and after meclofenamic acid infusion.2. Isoprenaline produced a fall in blood pressure, a reduction in oviduct motility and a reduction in uterine motility if the uterus showed marked spontaneous motility. PGF(2alpha) uniformly produced a fall in blood pressure and an increase in both uterine and oviduct contractility. PGE(1) produced a fall in blood pressure, a reduction in oviduct motility and no consistent effect on uterine motility.3. Meclofenamic acid selectively blocked the vasodepressor response to PGF(2alpha). The vasodepressor responses to PGE(1) and isoprenaline as well as the effects of all three agonists on uterine and oviduct contractility were not reduced by treatment with meclofenamic acid.4. Polyphloretin phosphate (PPP) administered to two rabbits in a cumulative dose of 94 mg/kg showed no significant blocking action on the vasodepressor or uterine and oviduct contractor responses to PGE(1) or PGF(2alpha) though this compound, like meclofenamic acid, has been reported to antagonize the actions of PGE(1) and PGF(2alpha) on isolated smooth muscle preparations.

Journal ArticleDOI
TL;DR: A rapid procedure has been developed in which an anion-exchange resin and spectrophotofluorometry are used to determine total porphyrins in urine and the precision indicates the precision to be very satisfactory.
Abstract: A rapid procedure has been developed in which an anion-exchange resin and spectrophotofluorometry are used to determine total porphyrins in urine. After porphyrins are eluted from the resin with 3N HCl, their fluorescence at 646 nm is measured with an Aminco-Bowman Spectrophotofluorometer. About 10 min are required per analysis by a skilled technician. Added to urine specimens, 95.3 ± 4.9% of uroporphyrin and 94.7 ± 9.6% of coproporphyrin, were accounted for. Eighteen normal urine samples contained an average of 0.063 µmol of porphyrin per liter (range, 0.028-0.176 µmol/liter). The coefficient of variation, 2.9%, indicates the precision to be very satisfactory.

Journal ArticleDOI
TL;DR: By competitively excluding proline from N 1 by adding methionine, it was possible to shift the uptake pattern of proline toward that of betaine, adding further support to the idea that proline is transported by both N 1 and N 2.

Journal ArticleDOI
TL;DR: In this paper, the authors reviewed the illness of 43 patients who had developed symptoms of chronic ulcerative colitis during their childhood or teenage years (1953-1966) and found that 71% of the patients had total colon involvement, and 65% had complications of the disease.
Abstract: This report reviews the illness of 43 patients who had developed symptoms of chronic ulcerative colitis during their childhood or teenage years (1953–1966). The clinical picture is similar to that observed in adults, although these patients appear more ill and disabled by their disease. When first seen, 71% of the patients had total colon involvement, and 65% had complications of the disease. At follow-up, 6 died, 2 had colectomies, 27 are under medical treatment, but only 15 remain relatively symptom-free. Nine are alive after surgery. One patient's status is unknown. In general, it is difficult to control ulcerative colitis that begins when the patient is young; it is associated with a high rate of mortality and morbidity. Earlier consideration should be given to surgical treatment when patients respond poorly or incompletely to medical treatment.

Journal ArticleDOI
TL;DR: The results indicate that pregnancy, labor, and the postpartum period produce no significant alterations in the epinephrine and norepinephrine content of the adrenal gland.


Journal ArticleDOI
TL;DR: In this article, arteriovenous fistulas following percutaneous renal biopsy have been observed in 3 children, one severely and another mildly hypertensive prior to biopsy, and bilateral fistulas were demonstrated.


Journal ArticleDOI
TL;DR: Male and female A/Jax mice 10–18 days of age were given one, two, or three daily subcutaneous injections of Serpasil and sacrificed 24 hours after the last injection to determine the effects of this catecholamine depleting drug on the dense cored cytoplasmic granules of the parenchymal chief cells.
Abstract: Male and female A/Jax mice 10–18 days of age were given one, two, or three daily subcutaneous injections of Serpasil (Reserpine USP; 2.5 mg/kg) and sacrificed 24 hours after the last injection. Abdominal extra-adrenal tissue was processed for electron microscopy to determine the effects of this catecholamine depleting drug on the dense cored cytoplasmic granules of the parenchymal chief cells. Electron microscopic investigations of sympathetic paraganglia from treated animals revealed a marked decrease in granule opacity as compared to that seen in cells from control animals. The cells with granules reduced in opacity following reserpine treatment could be consistently distinguished from those of non-treated animals which led us to assume that the drug depleted the amine content from its storage site in the granule without completely destroying the granule structure. These results further substantiate our earlier speculations that the granules in abdominal paraganglion chief cells of the mouse contain catecholamines.


Journal ArticleDOI
TL;DR: Passive-protection tests were conducted in mice with antisera from rabbits immunized with formalinized or heat-killed cells or with an alcohol-precipitated fraction from the slime layer and specificity was found to relate closely to the heat-stable "O" serotypes as defined by Verder and Evans.
Abstract: Passive-protection tests were conducted in mice with antisera from rabbits immunized with formalinized or heat-killed cells or with an alcohol-precipitated fraction from the slime layer. Protection was conferred by antisera against the heatstable antigens and correlated well with agglutinin levels. Specificity was found to relate closely to the heat-stable "O" serotypes as defined by Verder and Evans.

Journal ArticleDOI
TL;DR: It appears likely that glyceraldehyde phosphate dehydrogenase is a site of metabolic control in erythrocytes, and is clearly the rate-limiting reaction when the pH of the cells is raised or when the phosphate concentration of the external medium is increased markedly.

Journal ArticleDOI
TL;DR: It is indicated that human colostral macrophages interact with certain plant agglutinins in a manner distinct from mouse peritoneal macrophage.

Journal ArticleDOI
TL;DR: Information provided by this study and related evidence from other laboratories indicate that bubble embolism is not a significant factor in production of the microcirculatory aberrations of decompression sickness, however, introduction of large gas-liquid interfaces could be responsible for altering the components and rheologic characteristics of the blood.

Journal ArticleDOI
TL;DR: It is concluded that close packing in the matrix (obviously hexagonal in many instances) is the cause of the prismatic shape of the cristae.
Abstract: Further work with mitochondria containing prismatic cristae has revealed that this type occurs as a constant feature and in some abundance in the dorsolateral region of the spinal cord of the cat at cervical, thoracic and lumbar levels. All such mitochondria occur in astrocytes. The most common forms are long rods with an abundance of matrix and very few cristae. The matrix in the majority of such mitochondria is of moderate density and without discernible organization. In others the matrix consists of closely packed rodlets with or without occasional prismatic cristae. A frequent pattern is a core of longitudinal rodlets surrounded by a rim of circumferential ones. In the circumferential zone a single row of triangular cristae is present. The unusual mitochondria vary greatly in size, from 0.2–5.0μ Mitochondria containing ordered arrays of cristae that are triangular in cross section are for the most part much smaller than those with very few cristae and smaller than similar mitochondria described in the Syrian hamster. It is concluded that close packing in the matrix (obviously hexagonal in many instances) is the cause of the prismatic shape of the cristae.

Journal ArticleDOI
TL;DR: Since the functional effectiveness of systemic arterial or venous-pulmonary artery shunts is dependent primarily upon pulmonary vascular resistance, it seems important to determine what effect changes in blood viscosity have onmonary vascular resistance independent of changes in cardiac output.