Showing papers by "University of Miami published in 1974"

Pathophysiologic Observations in Prehospital Ventricular Fibrillation and Sudden Cardiac Death

Abstract: In order to better understand the problem of prehospital sudden cardiac death (SCD) two groups of individuals were studied. One group was monitored by rescue squads during attempted rescue. These subjects were defibrillated from prehospital ventricular fibrillation (VF) and hospitalized if they survived or autopsied if they could not be resuscitated. The second group were SCDs which were witnessed and described by observers. Detailed past histories of both groups were collected, and either clinical or autopsy diagnoses were obtained. On the day of death or VF, one quarter reported new symptoms (primarily chest pain and dyspnea) preceding collapse by more than 30 minutes, one quarter reported symptoms lasting from 1 to 30 minutes, and one half collapsed instantaneously or within 1 minute of acute symptoms. A history of old myocardial infarction (MI) was present in 41% and of angina pectoris in 54%, and 27% reported new or changing symptoms within four weeks. In defibrillated survivors, "would-be SCDs," ele...

Interspecific Aggression and its Relevance to the Concept of Territoriality in Reef Fishes

Abstract: Territorial behavior is a conspicuous determinant of social organization in many reef fishes. Field observations have indicated that an accurate description of a given organization must consider not only conspecific encounters but also those involving members of the other species which make up the behavioral community. Data, relevant to the above consideration, were gathered on the reef for the three-spot damselfish, Eupomacentrus planifrons , at intervals throughout the year. Experiments determined (i) the greatest distance from its residence (“maximum distance of attack”) that a territorial male would initiate attacks on given individuals of various species, and (ii) number of nips that such a male directed at “intruders” when the latter were placed adjacent to its residence. The “maximum distance of attack” was found to be characteristic for each “intruding” species: conspecifics—farthest from, congenerics—slightly closer to, and the remaining species—closest to the residence. Territorial males appeared to ignore any given fish until it had reached its respective boundary. Over a broad range, size within a given species appeared unimportant. The number of attacks directed at “intruders” adjacent to the residence was, however, less clearly species-specific. Both parameters varied seasonally in a parallel fashion, this seasonality reflecting closely the annual reproductive cycle of E. planifrons . General observations on populations of E. planifrons and other damselfishes were carried out by SCUBA and the use of underwater television. Results demonstrated that territorial males of E. planifrons not only recognize different species of reef fishes, but also that they possess serial territories whose areas of defense vary depending on the particular species of intruder present at the time. Random observations on other species of reef fishes indicate that this important feature of interspecific aggression is not unique to the single species tested here.

Elastase of Pseudomonas aeruginosa: inactivation of complement components and complement-derived chemotactic and phagocytic factors.

Abstract: A purified elastase from Pseudomonas aeruginosa was highly destructive for fluid-phase and cell-bound C1 and C3 and fluid-phase C5, C8, and C9. Inactivation of C4, C2, C6, and C7 by the enzyme varied from 0 to 67%. Low concentrations of elastase generated, then inactivated, a chemotactic factor from human C5 but not from C3. Higher enzyme concentrations inactivated the C5 chemotactic activity at a faster rate. Elastase treatment of sensitized pseudomonads containing cell-bound C3 reduced the phagocytic indexes of polymorphonuclear leukocytes. The data support the proposed chemopathogenic role of the elastase in generation of the characteristic non-inflammatory Pseudomonas vasculitis.

Relative contributions of Ca2+ influx and cellular Ca2+ release during drug induced activation of the rabbit aorta.

Abstract: Using the “La-method” for measuring45Ca entry into smooth muscle cells we were able to show that the slow phase of a norepinephrine induced contraction is dependent on Ca2+ influx. Similarly Ca2+ influx was stimulated during the slow phase of angiotensin II and histamine induced contractions. The large rapid initial phases of these three types of drug induced aortic contractions were dependent on a common intracellular Ca2+ store which was rapidly exhausted in the presence of extracellular La3+.

Vincristine Therapy of Idiopathic and Secondary Thrombocytopenias

Abstract: Idiopathic thrombocytopenia refractory to glucocorticoids and splenectomy remains a serious problem. Prompt benefit was obtained from vincristine in six of seven patients not splenectomized who were refractory to glucocorticoids and in nine of 13 patients refractory to both glucocorticoids and splenectomy. Five of the nine were also refractory to cyclophosphamide or azathioprine or both. Vincristine also benefited 10 of 10 patients with thrombocytopenia and serologic evidence of lupus erythematosus or its variants, some patients with various forms of bone-marrow insufficiency, and three of three with thrombocytopenia due to lymphocytic leukemia. Vincristine accordingly appears to be indicated in the management of several forms of thrombocytopenia refractory to splenectomy and glucocorticoids. Its value as compared to vinblastine, azathioprine, and cyclophosphamide remains to be determined. (N Engl J Med 291:376–380, 1974)

The brunhes epoch: isotopic paleotemperatures and geochronology.

Abstract: Oxygent isotopic analysis of a long piston core from the western equatorial Pacific has produced a record for the entire Brunhes epoch. This record can be correlated point by point with the isotopic records of previously analyzed Atlantic and Caribbean cores, leading to the construction of a generalized temperature curve for the entire Brunhes epoch.

Sinus node re-entry: a mechanism for supraventricular tachycardia.

Abstract: Data in 20 patients with normal sinus rhythm who, following induced premature atrial beats (PABs), manifested re-entry in the region of the sinus node are presented. PABs at coupling intervals ranging between 230-535 msec were followed by sinus node re-entry (SNR). Several criteria were applied to diagnose SNR: the temporal sequence of atrial excitation, the intra-atrial conduction time, the shape and polarity of the P waves, and manifestation of re-entry independent of atrioventricular (A-V) nodal delays. In 18 patients SNR lasting for one to several beats was observed. In the remaining two patients sustained SNR was manifested as supraventricular tachycardia (SVT), with cycle lengths ranging between 320-500 msec, which persisted for several minutes prior to its termination by properly timed atrial stimuli. In one of the latter two patients sustained SNR and SVT were produced only after atropine administration. Sinus node re-entry could be elicited at will in a specific echo zone with a duration ranging ...

Intramedullary pressure and pulmonary embolism of femoral medullary contents in dogs during insertion of bone cement and a prosthesis.

Abstract: Femoral medullary pressures and pulmonary embolization of medullary contents during the insertion of cement and a medullary rod in greyhounds were studied. In three animals, insertion of cement into the femoral shaft resulted in medullary pressures of between 290 and 900 torr and the appearance of medullary contents in the lungs within ten to 120 seconds. In five other animals, pulmonary embolization was not detectable when the rise in femoral medullary pressure was prevented by drilling a hole distal to the cemented area.

Effects of temperature and delayed feeding on growth and survival of larvae of three species of subtropical marine fishes

Abstract: In larvae of the bay anchovy Anchoa mitchilli (Valenciennes), the sea bream Archosargus rhomboidalis (Linnaeus), and the lined sole Achirus lineatus (Linnaeus), growth, survival, and starvation times were investigated at temperatures of 22° to 32°C. The rate at which hours after hatching until starvation decreased in relation to temperature for unfed larvae did not differ significantly among the 3 species, ranging from-5.4 to-6.3 h per degree increase in temperature. The total number of hours until starvation did differ for all 3 species: lined soles survived longest, bay anchovies were intermediate, and sea bream survived the least time. At 28°C, unfed sea bream could survive 90.1 h, bay anchovy 102.3 h, and lined sole 119.8 h. The eyes pigmented at nearly the same time after hatching for sea bream and bay anchovy, but took about 20 h longer at all temperatures for lined sole. Quadratic equations best described the relationship between hours after hatching when the eyes became pigmented and temperature. Eye-pigmentation times became nearly constant for all 3 species at temperatures above 28°C. At 28°C, eyes pigmented about 27 h after hatching for bay anchovy and sea bream but not until 47 h for lined sole. Hours after eye pigmentation when unfed larvae starved was a measure of the effective time that larvae had to commence feeding. Bay anchovies and lined soles were nearly alike in this respect, but sea bream starved at tewer hours after eye pigmentation. Slopes of regressions representing decrease in times to staration for increasing temperatures ranged from-3.7 to-4.4 h per degree increase in temperature, and were not significantly different among the 3 species. At 28°C, unfed lined soles starved at 70 a after eye pigmentation, bay anchovies starved at 72.5 h, and sea bream at only 62 h. Yolk absorption was most rapid for all species during the first 20 h after hatching, and was faster at higher temperatures. Amounts of yolk remaining at the time eyes became pigmented were less at higher temperatures for bay anchovy and lined sole, but were greater for sea bream, suggesting that sea bream used yolk more efficiently at higher temperatures. Either no yolk or small traces (>0.20%) remained at 24 h after eye pigmentation in all 3 species. Feeding was delayed for periods of 8, 16, 24, 32, 40 and 48 h after eye pigmentation for all species at a series of experimental temperatures from 24° to 32°C. Growth and survival were affected when food was withheld for more than 24 h at 28°C, but survival did not decrease markedly until food was withheld at least 8 h longer. At lower temperatures food could be withheld longer and at higher temperatures for less time. Feeding can be initiated by most larvae for several hours after all visible yolk reserves have been exhausted. All species tested can survive for 24 to 40 h after eye pigmentation at 24° to 28°C without food and still have relatively good growth and survival when food is offered. If the “critical period” is considered relative to time of hatching, lined soles need not find food for 3 to 3.5 days after hatching, but bay anchovy and sea bream must feed within 2.5 days of hatching.

Cyclic AMP accumulation and steroidogenesis in the human corpus luteum: effect of gonadotropins and prostaglandins.

Abstract: Prostaglandin E2 (PGE2) stimulates steroidogenesis in vitro in human corpus luteum slices, to a similar extent as hCG. This prostaglandin, as well as hCG and hLH also stimulates the incorporation of [8-3H] adenine into [8-3H] cyclic AMP in this in vitro system and this stimulation appears to be specific and dose related for these substances. The increase of [8-3H] cyclic AMP accumulation was found to be due to the stimulation of the synthetic adenyl cyclase enzyme system rather than the inhibition of the destructive phosphodiesterase enzyme system. Throughout the study, corpora lutea of the menstrual cycle were shown to be much more responsive to stimulation (hCG, LH, PGE2) in terms of steroid synthesis and cyclic AMP formation than corpora lutea of pregnancy. The reason for this difference between the two types of corpora lutea is not clear at this time but does not appear to be due to a deficiency in the adenyl cyclase system of pregnancy corpora lutea. The data of the present study brings our ...

Early and Late Effects of Coronary Artery Occlusion on Canine Purkinje Fibers

Abstract: The electrophysiological characteristics of subendocardial Purkinje and myocardial cells were studied during acute (within 30 minutes) and chronic (after 10 days) phases of myocardial infarction. Endocardial Purkinje and myocardial electrograms were recorded in vivo with bipolar electrodes before and after occlusion of the anterior descending coronary artery. Also, intracellular and extracellular potentials were recorded in vitro from the endocardial surface of infarcted regions of hearts excised during the acute and chronic phases. In the acute phase, Purkinje and myocardial potentials within the ischemic zone deteriorated in vivo, but they were not markedly delayed. Intracellular recordings in vitro showed partial depolarization of both Purkinje and myocardial cells. In the chronic phase, extracellular and intracellular Purkinje potentials recorded in vivo and in vitro from the infarcted zone usually did not differ from normal. No myocardial potentials were recorded from the endocardial surface of the chronic infarcts. Thus, subendocardial Purkinje and myocardial cells are affected early in infarction, but many Purkinje cells survive and return to normal.

Laboratory culture of the lobate ctenophore Mnemiopsis mccradyi with notes on feeding and fecundity

Abstract: Collection and culture of the large lobate ctenophore Mnemiopsis mccradyi Mayer is described, including the requirements for successful development of larvae. Particular attention must be given to the collection of these delicate animals, the handling and provision of live microzooplankton of suitable size for the larvae, and the provision of food densities for the adults which neither stimulate “wasteful” feeding nor limit their growth. Although these ctenophores will ingest detritus and algal cells in high concentration, they lost weight at the same rate as starved individuals unless provided with living zooplankton. Under optimum conditions, specimens would lay eggs within 13 days of their own birth. By the 17th day they laid eggs daily, and had produced an average of 8,000 eggs within 23 days after birth. The maximum number of eggs laid by a single wild individual within 24 h after being brought into the laboratory was 10,000. Their high fecundity, rapid generation time, and ability to self-fertilize help to explain their sudden appearance in bloom proportions at periods of high food concentration in the environment, often referred to in the literature.

Selective Distal Splenorenal Shunt: Technique and Results of Operation

Abstract: The selective distal splenorenal shunt has been evaluated from the standpoint of its effectiveness in control of gastrointestinal variceal hemorrhage in the cirrhotic and the metabolic changes induced by this procedure. It has been shown to be superior to total portosystemic shunting procedures in the metabolic aspects of the study and has a markedly lower incidence of encephalopathy as compared to previous data from our studies as well as those from numerous other investigators. The operative mortality has been progressively lowered and now has reached levels comparable to those experi

Microtubular organization in elongating myogenic cells

Abstract: Microtubule organization has been studied in serially sectioned myogenic cells in the tail muscle regeneration blastema of Rana pipiens tadpoles. In mesenchymal cells and in some premyoblasts, microtubules radiate from centriolar satellites in a cell center, while in more mature myoblasts and myotubes the centrioles no longer appear to serve as organizing centers for microtubules. In all elongate, fusiform myogenic cells, the microtubules are predominately oriented in the longitudinal axis of the cell. Counts of microtubules in transverse sections spaced at regular intervals along the cells show that the absolute number of microtubules is greatest in the thickened midregions of the cells and decreases relatively smoothly toward the tapered ends of the cells. Close paraxial association of microtubules (within 40 nm surface-to-surface) occurs along the entire lengths of cells but appears with greatest frequency in their tapered ends. In two myoblasts, serial sections were used to trace all microtubules in 8-µm long segments of the cells located about midway between the nucleus and one end of the cell. Since tracings show that as many as 50% of the microtubules terminate within the 8-µm long segment, it seems unlikely that any microtubules extend the entire length of the cell. It is proposed that lateral interactions between paraxial microtubules stabilize the overall microtubular apparatus and contribute to maintenance of the bipolar form of the cells. A three-dimensional model of the complete microtubular array in one of the 8-µm long segments of a myoblast has been constructed. The model reveals that a few microtubules within the segment are bent into smooth curves and loops that could be generated by sliding interaction between paraxial microtubules.

Retrograde Pre-excitation Comparison of Antegrade and Retrograde Conduction Intervals in Man

Abstract: The purpose of this report was to compare antegrade (atrioventricular [A-V]) and retrograde (ventriculoatrial [V-A]) conduction times in 124 consecutive patients who exhibited bidirectional conduction during diagnostic studies where His bundle recordings were obtained. None of these patients had any evidence of antegrade pre-excitation. The mean age was 64 ± 13 (range 32-89 years). The QRS complex was abnormal (≧ 0.11 sec) in 46 patients. The control mean P-R, A-H, and H-V times were 170 ± 37, 80 ± 21, 49 ± 8 msec, respectively. The A-V and V-A times were measured from local bipolar right ventricular (RV) and right atrial (RA) electrograms obtained via pacing catheters placed in the high RA and RV apex. Both RA and RV were paced at identical cycle lengths and the rate was progressively increased until block developed or to a cycle length of 400-330 msec. The V-A time was longer than A-V in 45 (group A), equal in 11 (group B), and shorter in 68 patients. Of the latter 68 patients (group C) in 49 V-A time was 172 ± 36 as compared to 197 ± 38 msec for A-V time, and while the interval lengthened at higher pacing rates, it remained shorter than A-V time throughout (197 ± 40 versus 261 ± 51 msec). In the remaining 19 patients (group D) the V-A was not only shorter than A-V (176 ± 27 versus 207 ± 49 msec) but remained unchanged up to the highest paced rates, whereas A-V time progressively lengthened 269 ± 81 msec). In group D a constant V-A time in all probability is indicative of retrograde impulse transmission through tissue other than the A-V node, i.e., bypass pathways functioning only in a retrograde direction. Progressively increasing A-V and V-A times in groups A to C suggest bidirectional conduction through a single common pathway. Our data demonstrate that: 1) V-A is less often longer (35%) and more often shorter (56%) than A-V; 2) In some patients retrograde pre-excitation and V-A may occur through bypass pathways, functional in the retrograde direction only. These findings may be of clinical significance.

Fine structure of intracranial hemangiopericytoma and angiomatous meningioma.

Abstract: Detailed study of fine structure of intracranial hemangiopericytoma shows that this neoplasm, formerly designated as capillary “angioblastic meningioma,” conforms in all respects to hemangiopericytomas encountered in other organ systems. Ultrastructural features of intravascular cells in transitional type “angioblastic meningioma” were similar to those described for meningiomas in general. The present observations reemphasize the possibility of a histogenetic relationship between intracranial hemangiopericytoma and hemangioblastoma and suggest the exclusion of both of these variants of vascular tumors from the group of meningiomas.

Paralytic pontine exotropia: A sign of acute unilateral pontine gaze palsy and internuclear ophthalmoplegia

Abstract: Paralytic external deviation of one eye with horizontal immobility of the fellow eye specifies an acute brainstem lesion involving the paramedian pontine reticular formation and the medial longitudinal fasciculus on the side opposite the deviated eye. This paralytic pontine exotropia is distinguished from other exotropias. The deviated (exotropic) eye shows abduction nystagmus during attempts to move it further laterally, and extreme slowness of adduction saccades. Normal midbrain ocular motor functions are evidenced by intact vertical gaze, convergence, and pupillary constrictor reflex activity.

Application of Enzymic Methods to the Structural Analysis of Polysaccharides: Part I

Abstract: Publisher Summary This chapter discusses the application of enzymes for the structural analysis of polysaccharides. The classical techniques of structural analysis of polysaccharides—namely, fragmentation analysis (for example, by acid hydrolysis), methylation analysis, and periodate oxidation have been supplemented to an ever-increasing extent by enzymic methods. The use of enzymes in the analysis of polysaccharide structures has become so extensive that it is now appropriate to survey the progress made by the application of such methods. The chapter illustrates how the two types of method, enzymic and nonenzymic, may usefully complement each other. This result may be achieved in several ways. In its simplest form, it merely involves nonenzymic characterization of products of enzymic hydrolysis or—more commonly—characterization, by simple enzymic procedures of products of low molecular weight that have been obtained by nonenzymic methods. Enzymatic procedures can be used in conjunction with nonenzymic or other enzymic methods to obtain quantitative data relevant to the elucidation of polysaccharide structure.