PubMed Health⌕ Search

Biomedical subjects

A Rodriguez

Publications and source records attributed to A Rodriguez.

At least 289 records · Page 16Linked to original sources
PubMed1989

Radiation damage to glucose concentrating capacity and cell survival in kidney tubule cells: effects of fractionation.

The glucose concentrating capacity of cultured LLC-PK1 kidney epithelial cells has been measured after single and fractionated doses of X-rays. Steady-state glucose concentrating capacity (ratio of glucose concentration inside to outside cell) can be measured using radiolabelled analogues of glucose which are actively transported but not metabolized. These cells can be stimulated to increase their glucose concentrating capacity (up-regulation) by a reduction in the glucose concentration of the growth medium. However, after X-ray irradiation the cells have a reduced capacity to respond to up-regulation. This effect can be measured 7 days after irradiation and before radiation-induced cell killing affects the cell population. The previously reported radiosensitivity of this function to single doses of X-rays (in the range 1-16 Gy) was confirmed. Surprisingly, no significant sparing of this effect could be measured by fractionation of the X-ray dose into two or four fractions. However, the cells showed a significant fractionation effect if clonogenic survival was measured using the standard cell survival assay. These early effects have different fractionation response from the later phases of tissue damage, measured months to years after irradiation, which do show sparing due to fractionation and are thought to be mainly due to changes in cell survival. The lack of sparing by fractionation to the functional damage may suggest a different target from that which determines cell survival. These results support the hypothesis that radiation damages cellular functions, separately from cell replication.

Biological Transport↗
PubMed1989

Acute acalculous cholecystitis in critically injured patients. Preoperative diagnostic imaging.

The potential lethality and predisposing factors of acute acalculous cholecystitis (AAC) are well established; however, preoperative diagnosis remains a challenge. This update of a previous report of 30 cases of AAC at a Level I trauma center describes 14 multiply injured patients who developed AAC and underwent cholecystectomy. All 14 patients had acutely inflamed gallbladders; 6 (42.8%) had areas of necrosis or gangrene. The mortality rate was 7% (1 patient). While the percentage of patients receiving prolonged intensive care (100%), narcotic analgesics (100%), and TPN (93%) correlates with the experience cited previously, the percentage undergoing preoperative diagnostic imaging is unusually high, reflecting a heightened suspicion for AAC. Computed tomographic or sonographic evidence of gallbladder wall thickness greater than or equal to 4 mm, pericholecystic fluid or subserosal edema without ascites, intramural gas, or a sloughed mucosal membrane was considered diagnostic criteria for AAC. We conclude that preoperative computed tomogram or ultrasound imaging leads to earlier recognition of this life-threatening problem.

Acute Disease↗
PubMed1989

Blunt chest trauma in the elderly.

Significant differences were identified between a group of elderly patients (65 years and older) and a nonelderly group both with blunt thoracic trauma. There was a lower incidence of elderly patients presenting in shock; however, cardiopulmonary arrest at arrival was more frequent in this group. Although the types of complications were similar in both populations, the morbidity and mortality rates were higher in the elderly. A high index of suspicion must be generated for an elderly patient who has sustained blunt chest trauma. An aggressive diagnostic and therapeutic approach may lead to a decrease in the high morbidity and mortality rates in the elderly.

Age Factors↗
PubMed1989

Reversible ATP-dependent inactivation of glycerolphosphate acyltransferase from rat adipose tissue.

Microsomal glycerolphosphate acyltransferase from rat adipose tissue is shown to be inactivated with time upon incubation with ATP. The inactivation can be observed in postmitochondrial supernatant as well as in washed microsomes. However, the effect is more pronounced upon addition of the cytosolic fraction. This activity is specific for ATP, is dependent on the nucleotide concentration, and is prevented when ATP is substituted by beta,gamma-methylene-ATP. Some protection is provided by amiloride but not by EGTA or cAMP-protein kinase inhibitor. Also, the level of enzyme inactivation is not modified by addition of cAMP-dependent protein kinase and its substrates. Inactivated glycerol-phosphate acyltransferase from ATP-treated microsomes can be reactivated by incubation with partially purified protein phosphatase from rat liver. These results suggest the existence in adipose tissue of a protein kinase (cAMP independent) that may be involved in the regulation of glycerolphosphate acyltransferase.

Acyltransferases↗
PubMed1989

Development of the ventral striatum in the lizard Gallotia galloti.

The ventral striatum nucleus (VS) begins development at Stage 31 (E. 31) from the neuroblasts which proceed from the cellular proliferation of both the ventral and terminal sulci. The ultrastructural features of the neuroblasts of VS between E. 31 and E. 34 have the aspect of immature cells, but as from E. 38 neuronal maturity is gradual until hatching. At E. 34 cellular death occurs. The first degenerated cells belong to Type I (nuclear degeneration) of the pycnotic cells; as from E. 40 cytoplasmic degeneration appears. Vascularisation starts at E. 35 and from E. 38 the first synaptic contacts are observed, especially those of the axodendritic type.

Animals↗
PubMed1989

An evaluation of the results of a drug sample analysis.

An analysis of drug samples received by the National Toxicology Institute at Madrid during the period from September 1985 to May 1987 was undertaken with a view to carrying out an epidemiological assessment of drug abuse. Of 414 street drug samples, 63.5 per cent contained heroin, 12.5 per cent cocaine, 8.5 per cent amphetamine and 15.4 per cent other substances. The concentration of heroin ranged from 21 to 60 per cent in most of the samples (91.8 per cent) that contained it. Similar concentrations of cocaine were found in the samples containing that substance. Adulterants were detected in 78.8 per cent of the samples containing heroin, 59.6 per cent of the samples containing cocaine and 56 per cent of the samples containing amphetamine. The most common adulterants in the samples containing heroin were caffeine (68.4 per cent), phenobarbital (19.7 per cent), methaqualone (13.4 per cent) and procaine (13.4 per cent), while lidocaine was the most common adulterant (52 per cent) in the samples containing cocaine.

Amphetamines↗
PubMed1989

Methodologic approach for a large functional trauma registry.

The utility of a clinical trauma registry (TR) is directly related to the constituents of the data base and to the accuracy of the data, which is contingent on a carefully constructed data collection system. A TR was developed by traumatologists at a busy Level I trauma facility that predominantly receives patients having incurred blunt injury. Four dedicated data collectors gather the AP information within 24 to 48 hours after admission, with prompt Attending Surgical review for verification. Examples of data output prove this is a functional system. Using a careful methodologic approach for design and implementation, clinicians can create a large, functional trauma registry with many potential applications.

Data Collection↗
PubMed1989

Quiescence in 9L cells and correlation with radiosensitivity and PLD repair.

The onset of quiescence, changes in X-ray sensitivity, and changes in capacity for potentially lethal damage (PLD) repair of unfed plateau-phase 9L44 cell cultures have been systematically investigated. The quiescent plateau phase in 9L cells was the result of nutrient deprivation and was not a cell contact effect. Eighty-five to 90% of the plateau-phase cells had a G1 DNA content and a growth fraction less than or equal to 0.15. The cell kinetic shifts in the population were temporally correlated with a developing radioresistance, which was characterized by a larger shoulder in the survival curve of the quiescent cells (Dq = 5.71 Gy) versus exponentially growing cells (Dq = 4.48 Gy). When the quiescent plateau-phase cells were refed, an increase in radiosensitivity resulted which approached that of exponentially growing 9L cells. Delayed plating experiments after irradiation of exponentially growing cells, quiescent plateau-phase cells, and synchronized early to mid-G1-phase cells indicated that while significant PLD repair was evident in all three populations, the quiescent 9L cells had a higher PLD repair capacity. Although data for immediate plating indicated that 9L cells may enter quiescence in the relatively radioresistant mid-G1 phase, the enhanced PLD repair capacity of quiescent cells cannot be explained by redistribution into G1 phase. When the unfed quiescent plateau-phase 9L cells were stimulated to reenter the cell cycle by replating into fresh medium, the first G1 was extended by 6 h compared with the G1 of exponentially growing or refed plateau-phase 9L cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Line↗
PubMed1988

The dependency ratio and optimum population growth. The total utility case.

"This paper examines the effects of introducing a variable dependency ratio in Dasgupta's (1969) model. We consider a case in which the probability of dying as well as the rate of participation in the labor force change with age. It is shown that the inclusion of those realistic demographic features slows down the optimal rate of population growth and increases the rate of consumption. In spite of the reduction in the rate of population growth, this rate can still be positive. The sensitivity of the solutions to changes in the demographic parameters of the model is examined."

Demography↗
PubMed1988

Effects of D-penicillamine on mononuclear cells in vitro.

D-penicillamine (D-pen) inhibited pokeweed mitogen-induced plaque-forming cell (PFC) response in a dose-dependent manner. This inhibition was irreversible as preincubation for a few hours with the drug followed by washes still caused suppression of the PFC response. Pretreatment of the different mononuclear cell populations with D-pen for short periods (2-24 h) showed that both macrophages (Mo) and B lymphocytes were affected by the drug. By contrast T cells were resistant. Mo appears to be more susceptible to D-pen than B cells, and in the case of drug-treated Mo, the response was restored completely with the addition of 20% fresh Mo. Our results show that D-pen, without exogenous Cu2+, inhibits the polyclonal immunoglobulin secretion by human mononuclear cells in vitro due to a strong effect on both Mo and B cells. This may explain the decrease in serum immunoglobulin levels seen in patients with rheumatoid arthritis undergoing this therapy.

B-Lymphocytes↗
PubMed1988

Clinical significance of radionuclide angiographically-determined abnormalities following acute blunt chest trauma.

Abnormalities of right and left ventricular ejection fraction and segmental wall motion may be detected by radionuclide angiography (RNA) following blunt chest trauma. Of 111 patients with blunt chest trauma who were admitted to a large regional shock trauma center and underwent combined first-pass and equilibrium gated RNA, abnormalities were present in 40 (36%). These abnormalities were confined to the right ventricle in 33 patients. There was a positive association between RNA abnormalities and the presence of right bundle branch block (10 of 40, p less than 0.05) and a negative association between RNA abnormalities and the finding of rib fractures (6 of 40, p less than 0.05). The in-hospital death rate of these patients was low (3 of 40 patients with an abnormal RNA and 2 of 71 patients with a normal RNA). Follow-up RNA was performed at 10 +/- 4 days in 26 of the 40 patients with initially abnormal scans, and 22 (85%) of the 26 had reverted to normal. Thus although RNA abnormalities appear common following blunt chest trauma, among patients who survive for more than 24 hours and who undergo subsequent RNA, the complication rate is low despite an abnormal scan. We conclude that routine RNA adds little to clinical management following acute blunt chest trauma.

Adult↗
PubMed1988

Management of major tracheobronchial ruptures in patients with multiple system trauma.

Major tracheobronchial injury presents special problems in the context of multiple system trauma. A 14-year review of a clinical experience revealed eight patients who had operative repair of major bronchial or intrathoracic tracheal injuries. The diagnosis was suspected by subcutaneous emphysema, and especially by persistent pneumothorax or a significant air leak. Bronchoscopy confirmed the diagnosis in all patients before thoracotomy. All eight patients had multiple system injuries. All five with abdominal injuries were hypotensive at admission and underwent celiotomy before thoracotomy. The decision to perform thoracotomy or celiotomy first in patients with major tracheobronchial injuries and concomitant abdominal trauma must be individualized. If both injuries are recognized simultaneously and the patient is hemodynamically unstable but has adequate oxygenation and ventilation, the celiotomy can be performed first. On the contrary, if oxygenation and ventilation are the most threatening problems in a hemodynamically stable patient despite evidence of hemoperitoneum, the bronchial repair should have priority.

Adolescent↗
PubMed1988

IgG4 in human colostrum and human milk: continued local production or selective transport from serum.

Colostrum, mature milk, and paired plasma samples were obtained from 10 postpartum women who had not been previously studied. The geometric mean concentration of IgG4 in colostrum (3.3 micrograms/ml) was similar to the mean concentration in mature milk (3.0 micrograms/ml). The arithmetic mean for the percent of IgG = IgG4 was 10.3 +/- 3.3% for colostrum, 10.3 +/- 3.1% for mature milk, 2.6 +/- 0.3% for early plasma, and 1.7 +/- 0.3% for later plasma. Local mammary production of immunoglobulin was determined by subtracting the estimated serum contribution from the measured concentration in colostrum or milk. Evidence for local mammary production of IgG4 was found in 5 of 10 colostrum samples and 8 of 10 mature milk samples. These observations indicate that the previously observed selective enrichment of IgG4 in colostrum is also true for mature milk. These are the first studies suggesting continued local production of any immunoglobulin other than IgA in mature human breast milk.

Colostrum↗
PubMed1988

Adipose tissue glyceride synthesis in patients with hyperapobetalipoproteinemia.

Adipose tissue was obtained at thoracotomy in five control patients with valvular heart disease, all of whom were free of coronary artery disease and all of whom were normolipidemic with normal low density lipoprotein apolipoprotein B levels, and eight patients with coronary artery disease, all of whom had hyperapobetalipoproteinemia. In both groups, the rates at which linoleic acid and palmitic acid were incorporated into diglyceride and triglyceride were determined in vitro. The data indicate that fatty acid incorporation into adipose tissue glycerides was twice as rapid in controls as in patients with hyperapobetalipoproteinemia. By contrast there was no difference between the groups in the rate of net lipolysis of adipocyte glyceride. The data at hand do not establish the mechanism responsible for the difference in synthesis between normal subjects and patients with hyperapobetalipoproteinemia, but this may explain the delayed chylomicron triglyceride clearance previously observed in the disorder.

Adipose Tissue↗
PubMed1988

Morphology of the lumbar vertebral canal.

In a series of 215 anteroposterior X-ray films, a study was made of the horizontal distance between the pedicles of each lumbar vertebra, first of all sequentially, describing the morphology adopted by the lateral limits of the canal, and secondly determining the absolute value for each level separately and in relation to the variables of sex and age. The absolute value of this distance at each level is related to the thickness of the pedicles and the width of the vertebral bodies of L3 and L4. The values obtained were tested with the appropriate statistics in each case.

Adult↗
PubMed1988

Mediastinal tumors presenting as spontaneous hemothorax, simulating aortic dissection.

The usual causes of hemomediastinum and hemothorax include chest trauma, rupture of an aortic aneurysm or aortic dissection. We report two patients who presented with a clinical picture of aortic dissection. In both patients, the chest radiograph revealed anterior mediastinal masses. Aortic dissection could not be excluded on the basis of the chest radiograph, and additional investigation by thoracic aortography was performed. The tumors had undergone spontaneous bleeding into the mediastinum and the pleural space, presumably causing the patients pain. The interesting and unusual causes of spontaneous hemomediastinum and hemothorax are reviewed.

Adult↗
PubMed1988

A randomized trial of tamponade or sclerotherapy as immediate treatment for bleeding esophageal varices.

Sengstaken-Blakemore tamponade is used for the initial control of bleeding esophageal varices (BEV), although it is known to be potentially dangerous. Sclerotherapy has been shown to be effective in the treatment of BEV. This trial has been designed to evaluate comparatively the effectiveness of both procedures in the initial control of the hemorrhage. Forty-three patients with BEV were included in the trial. Twenty patients (group SB) were treated by tamponade. Twenty-three patients (group ST) were treated by sclerotherapy by means of a simple technique. During the first 24 hours, hemostasis was obtained in 16 of the SB patients and in all 23 of the ST patients (p less than 0.05). At seven days, nine SB patients and 19 ST patients were free of hemorrhagic relapse (p less than 0.05). By stratifying in relation to hepatic failure, the difference was greater (p less than 0.005) if patients with Child's A classification were excluded. It is concluded that sclerotherapy should be undertaken in almost every instance at the same moment that diagnosis is made, bypassing the intermediate step of tamponade.

Balloon Occlusion↗