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Biomedical subjects

M Rodriguez

Publications and source records attributed to M Rodriguez.

At least 649 records · Page 36Linked to original sources
PubMed1985

Effect of dialysis and ultrafiltration on osmolality, colloid osmotic pressure, and vascular refilling rate.

The effect of regular dialysis and isolated ultrafiltration on plasma osmolality, plasma colloid osmotic pressure (COP), plasma volume, and vascular refilling rate was evaluated in maintenance dialysis patients. Nineteen patients underwent regular dialysis and 11 isolated ultrafiltration. Blood samples from these subjects were obtained from arterial or venous dialysis system ports and peripheral veins. For any decrease in plasma volume, there was an increment in COP with each procedure in both venous and arterial ports and the presence of a progressive decrease of plasma osmolality was observed only during regular dialysis. Second, five additional patients underwent 2 hrs of regular dialysis and isolated ultrafiltration in separate sessions removing comparable amounts of fluid (approximately 2.5 liter); after 2 hrs, there were no differences in the changes of plasma volume and COP, but again plasma osmolality decreased only during regular dialysis. These studies demonstrate that moderate changes in plasma osmolality do not affect COP. Furthermore, the ability of the plasma to recruit fluid and generate vascular refilling (as assessed by COP) is similar during regular dialysis and isolated ultrafiltration, provided the rates of ultrafiltration are the same.

Adult↗
PubMed1985

Characterization of a major protein with a molecular weight of 160,000 associated with the viral capsid of Epstein-Barr virus.

A monoclonal antibody designated V3 was produced against a late protein associated with the Epstein-Barr virus-induced viral capsid antigen complex. The antibody reacted with discrete patches in the nuclei of infected cells as well as with virus particles, as shown by immunofluorescence and ultrastructural immunoperoxidase staining. The molecular weight of the protein precipitated by this monoclonal antibody was ca. 160,000. All anti-viral capsid antigen antibody-positive sera tested in an enzyme-linked immunosorbent assay reacted with this purified protein. The synthesis of the antigen was inhibited by phosphonoacetic acid but was not affected by tunicamycin, indicating that this was a late nonglycosylated viral protein. No differences were noted between the protein isolated from the P3HR-1 and B-95-8 cell lines as determined by immunoprecipitation and peptide mapping. By isoelectric focusing, this protein had a pI on the basic side ranging from 7.5 to 9.0.

Antibodies, Monoclonal↗
PubMed1985

Demyelination induced by Theiler's virus: influence of the H-2 haplotype.

Demyelination induced by Theiler's virus was examined in nonrecombinant H-2 congeneic strains of mice on common backgrounds expressing independent haplotypes. Light and electron microscopy of spinal cord sections from mice with s, f, p, r, v, or q haplotypes on a C57BL/10 background showed perivascular inflammation and multifocal areas of demyelination in the white matter. The demyelination in these mice was usually associated with clinical neurologic deficits. In contrast, mice with identical genetic backgrounds but b, k, or d haplotypes showed no pathologic or clinical abnormalities. Qa or Tla haplotypes did not appear to influence demyelination. The observations support the hypothesis that susceptibility to Theiler's murine encephalomyelitis virus-induced demyelination is influenced by genes that are linked to the H-2 complex. The findings suggest that the demyelination may be mediated by immune cells rather than being a direct cytolytic effect of virus on oligodendrocytes.

Animals↗
PubMed1985

Virus persists in beta cells of islets of Langerhans and infection is associated with chemical manifestations of diabetes. II. Morphologic observations.

Persistence of lymphocytic choriomeningitis (LCM) virus in the islets of Langerhans was associated with mild hyperglycemia and abnormal glucose tolerance test results. Early histopathologic events consisted of occasional perivascular inflammatory mononuclear cells around both islet and acinar cells. Morphometric studies showed an increase in the size of islets from virus-infected mice. By electron microscopy, LCM virions were found within infected beta cells. Cytolytic injury of beta cells was minimal and did not account for the abnormalities of glucose metabolism. In contrast to the findings in islets, ultrastructural studies of acinar cells revealed LCM virions in abundance, vacuolar degeneration, and intracytoplasmic inclusions. This study extends the previous observation that LCM virus infection may persist in beta cells of the islets of Langerhans without causing structural injury but be associated with abnormalities resembling the chemical and histopathologic features of the early stage of Type II (adult-onset) human diabetes mellitus.

Animals↗
PubMed1984

Pineal indols and testosterone affect exploratory activity of male rats.

The testosterone level has an inverse relation to activity in the open-field test. This is more important in red light than in white light. Pineal indols do not disturb this action. Some of these results are consistent with the assumption that androgens play a role on the exploratory activity of adult subjects.

Animals↗
PubMed1984

Microangiopathy of vasa nervorum in dysglobulinemic neuropathy.

Thickening of vessel walls resulting from endothelial proliferation was observed in the vasa nervorum of eleven patients with peripheral neuropathy associated with dysglobulinemia. Electron microscopy showed endothelial proliferation accompanied by abnormal accumulation of masses of intracytoplasmic filaments in each case. Of the eleven patients with dysglobulinemia, nine had monoclonal gammopathy and two were found to have polyclonal elevation of gamma globulin levels. Symptoms of neuropathy characteristically preceded detection of serum protein abnormalities by months to years. Nerve fiber lesions involved primarily the axon in four cases; segmental demyelination was the principal abnormality in the other seven. Both abnormalities were present to some degree in all eleven patients. Biphasic myelinopathy with uniform separation of myelin lamellae attributable to globulin deposition was observed in four cases. The microvascular changes included endothelial cytoplasmic enlargement, virtually obliterating the vessel lumen in many instances, with thickening of pericytes, in which intracytoplasmic filaments were prominent and pinocytotic vesicles numerous. No extracellular filaments were noted, and amyloid stains were negative. Possible effects of these microvascular changes include ischemia resulting from severe vascular luminal narrowing, and altered vascular permeability. Severe loss of axons in this group of neuropathies may be the result of ischemia, whereas altered vascular permeability may admit globulin into the endoneurium, where it may directly affect the myelin sheath and precipitate demyelination.

Adult↗
PubMed1984

Different roles of catecholaminergic and serotoninergic neurons of the medial forebrain bundle on male rat sexual behavior.

The medial forebrain bundle (MFB) plays an important role in the central elaboration of male sexual behavior. However the role of its ascending monoaminergic systems is not well understood. By selective lesions of catecholaminergic and serotoninergic axons of the MFB, produced with 6-OHDA and 5-7-DHT respectively, its possible involvement in male sexual behavior was studied. The evaluation of the behavioral patterns was studied by means of a microcomputer which also permitted the quantification of sequences in the sexual behavior patterns. Lesions with 5-7 DHT increased the intromission-ejaculation sequences and the percentage of ejaculatory males, without modifying other behavioral tests. Lesions with 6-OHDA diminished the number of "active" sexual patterns and motor activity. In order to check the specificity of the chemical lesions, the in vitro uptake of labeled norepinephrine and serotonin was measured, 5-7 DHT lesioned rats show a reduction in the uptake of 5-HT-C14 in the MPOA while 6-OHDA group show a reduction of NA-H3 in the striatum.

Animals↗
PubMed1984

Synthesis and antitumor evaluation of some nitrosourea and nitrogen mustard amino acid derivatives.

A series of (2-chloroethyl)nitrosourea and nitrogen mustard amino acid derivatives have been synthesized for antitumor evaluation. Reaction of an appropriate N-protected amino acid with 2-chloroethylamine followed by removal of the N-protecting group and condensation with an active (2-chloroethyl)nitrosocarbamate yielded N-[(2-chloroethyl)nitrosocarbamoyl]amino acid (2-chloroethyl)amides. Antitumor evaluation was performed against leukemia L1210, in vivo, in mice. These derivatives exhibited very interesting activities, particularly the sarcosine and gamma-aminobutyric acid derivatives.

Animals↗
PubMed1984

Peptide sweeteners. 7. Taste relationships of trifluoroacetyl-L-aspartylanilides.

A series of analogues of trifluoroacetyl-alpha-L-aspartylanilides substituted at various positions on the aromatic ring was synthesized and tasted. The position of the substitution is essential for the nature of the taste response. The results clearly establish the close relationship between sweet and bitter taste for these compounds. Combined electronic and topochemical contributions are discussed.

Anilides↗
PubMed1984

Effects of monoamine neurotoxins injected in different brain areas on gonadotropin and androgen secretion in the male.

In order to investigate the relative contribution of the serotoninergic and catecholaminergic innervation of different brain structures to the control of gonadotropin secretion in the male, adult rats were given bilateral injections of the selective neurotoxins, 5,7-dihydroxytryptamine and 6-hydroxydopamine, into the mediobasal hypothalamus, the medial preoptic area, the amygdala, and the medial forebrain bundle. Serum levels of luteinizing hormone (LH), follicle-stimulating hormone, testosterone, pituitary follicle-stimulating hormone, and LH content were measured 15 days later. The medial preoptic area 5,7-dihydroxytryptamine injections were followed by 2- to 3-fold increases of serum LH and testosterone levels and pituitary LH concentration. The 6-hydroxydopamine injections in the medial forebrain bundle resulted in a 60% decrease of pituitary LH content, associated with serum levels of LH and testosterone which were lowered, although not significantly. None of the treatments seemed to influence either serum or pituitary concentrations of follicle-stimulating hormone. These results suggest a hitherto undocumented major function of the serotoninergic innervation of the medial preoptic area in the control of LH secretion in the male and confirm previous reports indicating that some of the catecholaminergic fibers carried by the medial forebrain bundle can be modulatory for LH secretion.

5,6-Dihydroxytryptamine↗
PubMed1984

Effects of abdominal and thoracic breathing on breathing pattern components in normal subjects and in patients with chronic obstructive pulmonary disease.

The purpose of this study was to assess the effect of voluntarily controlled breathing maneuvers on breathing pattern components measured noninvasively with the respiratory inductive plethysmograph. In normal subjects, these maneuvers included predominantly thoracic and abdominal patterns with and without visual reinforcement from video-displayed plots of rib cage versus abdominal loops. In patients with chronic obstructive pulmonary disease (COPD), only predominantly abdominal breathing without and with visual feedback was employed; the latter produced greater abdominal contribution to tidal volume. Voluntarily controlled breathing patterns led to increased minute ventilation (VI) in normal subjects because of variable changes of frequency and tidal volume. This increase in ventilation was achieved despite increased asynchronous and paradoxic motion between rib cage and abdominal excursions that would add to the work of breathing. Patients with COPD had heightened baseline respiratory center drive when compared with that in normal subjects, as evidenced by elevation of VI and mean respiratory flow (VT/TI). In contrast to normal subjects, abdominal breathing produced no change in VI and VT/TI for the group as a whole, but 6 of the 9 patients with COPD had decreases compared with natural breathing. This diminution of respiratory drive in some patients with COPD during voluntary abdominal breathing might relate to limitation of ventilatory response by the increased work of breathing caused by pulmonary hyperinflation, elevated airway resistance, and increased asynchronous and paradoxic motion of the rib cage to the abdominal excursions, and/or the mental activity required to perform the breathing maneuver might be inhibitory to respiratory drive.

Abdomen↗
PubMed1984

Assessment of asynchronous and paradoxic motion between rib cage and abdomen in normal subjects and in patients with chronic obstructive pulmonary disease.

Both scalar tracings and XY plots of rib cage (RC) and abdominal (AB) excursions were analyzed to detect asynchronous and/or paradoxic motion of one compartment with respect to the other in an effort to distinguish differences between normal subjects and patients with chronic obstructive pulmonary disease (COPD). An inspiratory asynchrony index (IAI) was obtained by connecting a straight line from beginning inspiration to end inspiration of the RC-AB loop, and dividing the area enclosed by the inspiratory portion by the tidal volume. In like manner, an expiratory asynchrony index (EAI) was computed. Values of IAI and EAI in the supine posture were greater in patients with COPD than in normal subjects, and such differences were consistently demonstrated during natural and voluntarily controlled abdominal breathing. Paradoxic motion as percent of volume or time period of inspiratory and expiratory compartmental excursions was indicated when RC or AB compartments moved in an opposite direction to the sum of the two. During natural breathing, paradoxic motion was almost absent in normal subjects and variably present in patients with COPD. Voluntarily controlled breathing patterns produced increased IAI, EAI, and paradoxic motion. Passive tilting from supine to the upright posture did not affect indexes in normal subjects but reduced asynchronous and paradoxic motion of the RC in patients with COPD. Other indexes of loop analysis, such as phase angle and maximal compartment amplitude/tidal volume, were not as consistent in distinguishing between normal subjects and patients with COPD during natural and voluntarily controlled breathing patterns.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdomen↗
PubMed1984

Influence of phase feeding available phosphorus on egg production characteristics, carcass phosphorus content, and serum inorganic phosphorus levels of three commercial layer strains.

An experiment was conducted to obtain information on the concept of progressively decreasing dietary phosphorus levels (phase feeding) on the performance of three different commercial layer strains. Dietary available phosphorus (AP) levels of .15, .30, or .45% were fed continuously from 22 to 70 weeks of age. Concurrently, a diet containing .35, .25, and .15% AP was phase-fed during age intervals of 22 to 34, 34 to 50, and 50 to 70 weeks, respectively. Dietary AP levels did not significantly affect egg production except the .15% AP level, which significantly reduced egg production when compared with the other three dietary AP treatments. Efficiency of feed utilization was significantly superior for hens phase-fed AP compared with hens fed the other AP treatments. There were no differences in egg weight or mortality due to dietary AP. Eggshells were significantly thicker when hens received .15% AP. The .15% AP and phase-fed regimen resulted in hens with significantly lower body weights at the end of the experiment. Hens fed .30% AP and phase-fed AP had significantly lower carcass ash and phosphorus levels. Serum phosphorus levels corresponded directly to dietary AP levels. There were no significant differences in egg production due to strain nor were there any strain by dietary treatment interactions that influenced production traits. Significant strain differences were noted in feed efficiency, egg weight, carcass ash, and carcass phosphorus.

Animal Feed↗
PubMed1984

Radiographic evidence of asbestos effects in American marine engineers.

Marine engineers undergoing routine annual chest roentgenography showed an unusual prevalence of pleural abnormalities including plaques suggestive of past asbestos exposure. A pilot survey, and a subsequent comprehensive study of the films of more than 5,000 men, showed an overall prevalence of 12% with pleural abnormality (typical calcification or plaque, or diffuse thickening). Prevalence of films classifiable for pneumoconiotic small opacities was negligible--1.2% in the pilot study. Prevalences of pleural abnormality were significantly higher among men with longer union membership, after controlling for age. Older merchant ships contain substantial amounts of asbestos-containing thermal insulation. Marine engineers often remove and reapply insulation, operations known to produce high airborne fiber concentrations. These roentgenographic survey results indicate significant past asbestos exposures of ships' engineering department personnel.

Adult↗
PubMed1983

Persistent infection of oligodendrocytes in Theiler's virus-induced encephalomyelitis.

Mice infected with Theiler's murine encephalomyelitis virus (TMEV) develop a chronic relapsing demyelinating myelitis. To determine the localization of viral antigen in infected cells of the spinal cord, we studied TMEV-infected SJL/J mice using immunoelectron microscopic peroxidase-antiperoxidase techniques. Viral antigens were expressed in the cytoplasm of neurons and astrocytes 4 and 11 days postinfection. At 28 days postinfection, macrophages, astrocytes, and oligodendrocytes showed viral antigen in their cytoplasm. At 45, 83, 270, and 360 days postinfection, most infected cells were oligodendrocytes as revealed ultrastructurally by immunoperoxidase staining of prominent glial loops that connect with myelin lamellae. Some of these sheaths also showed Schmidt-Lanterman incisures that stained for viral antigen. Virus could be recovered at low titers for the duration of the illness. The findings indicate that TMEV induces persistent infection of oligodendrocytes which could then become the target of immune-mediated injury resulting in demyelination.

Animals↗