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Biomedical subjects

F Lara

Publications and source records attributed to F Lara.

15 recordsLinked to original sources
PubMed2001

General binocular disorders: prevalence in a clinic population.

The purpose of this paper was to study the prevalence of nonstrabismic accommodative and binocular dysfunctions in a clinical population. We examined 265 symptomatic patients who were chosen from an optometric clinic. We performed several tests to diagnose any form of refractive, accommodative or binocular dysfunction. Of the 265 subjects examined, 59 patients (22.3%) had some form of accommodative or binocular dysfunction and required not just the correction of the refractive error but a specific treatment for each of the problems diagnosed. The remaining subjects were classed as having refractive anomalies. The frequency of binocular dysfunctions was 12.9%, and 9.4% for accommodative anomalies. Convergence excess (4.5%) was more prevalent than convergence insufficiency (0.8%) and accommodative excess (6.4%) more prevalent than accommodative insufficiency (3%).

Accommodation, Ocular↗
PubMed2000

[Patient assessment of the long-term benefits of surgery in inflammatory bowel disease].

UNLABELLED: The objective of surgical treatment in ulcerative colitis (UC) and Crohn's disease (CD) differs. Surgery in UC is more aggressive and potentially curative whereas in CD it is more conservative and palliative. OBJECTIVE: To assess the opinion of patients with inflammatory bowel disease who underwent surgery in the distant past about the results and timing of surgery. MATERIAL AND METHODS: A total of 50 surgical patients (36 with CD and 14 with UC) who had undergone an intestinal surgical procedure at least one year before. The clinical characteristics of patients and details of surgery procedures were recorded. Also, a personal interview was conducted. Patients were asked about their current clinical status, surgical consequences and their opinion about the appropriate timing of surgery. RESULTS: Surgery for UC was total proctocolectomy in 85% of patients and it was on an emergency basis in 43% of them. Surgery for UC was partial intestinal or colonic resection, and it was on an emergency basis in 22% of them. Postsurgical complications were more common in UC than CD patients (50% versus 20%; p < 0.05). In CD surgery, recurrence of disease occurred in 78% of patients within a 2.6 years interval. Among UC and CD patients, 71% and 50%, respectively, reported that their presurgical expectatives had been fulfilled (p = 0.17). CONCLUSIONS: Surgery for UC is associated with an appreciable rate of complications; however, most patients had their expectatives fulfilled with surgery as long-term symptoms were controlled. As for CD, the patient's satisfaction degree was lower than or UC.

Adult↗
PubMed2000

Alcohol ingestion inhibits the increased secretion of puberty-related hormones in the developing female rhesus monkey.

Alcohol (ALC) use and abuse by adolescents has been rising at an alarming rate. Whether ALC consumption during prepubertal years affects specific hormones and the process of sexual maturation is not known. We used immature female rhesus macaques to assess the effects of ALC on circulating levels of hormones known to be critical for the pubertal process. Ten monkeys averaging 20.3 +/- 0.3 months of age were bled by saphenous vein puncture at 0830 and 2030 h each day for 5 consecutive days to determine baseline levels of GH, insulin-like growth factor I, FSH, LH, estradiol (E2), and leptin. For the next 12 months, each day at 1330 h five monkeys were administered ALC (2 g/kg), and five monkeys were administered an isocaloric sucrose solution via a nasogastric approach. Blood was again collected twice daily on 5 consecutive days at 24, 28, and 32 months for hormone analysis. Food consumption and weight gain were similar for ALC-treated and control animals. The expected night-related increase in serum GH occurred during late juvenile development (28-32 months of age) in control animals, but was suppressed (P < 0.05) in ALC-treated animals. This action was paralleled by a decrease (P < 0.01) in serum insulin-like growth factor I. Serum LH and E2 were also depressed by ALC, with their effects most pronounced at 32 months (LH, P < 0.01; E2, P < 0.001). Serum FSH and leptin were not altered. Although ALC did not affect age at menarche, the interval between subsequent menstruations was lengthened (P < 0.05), thereby showing that ALC affected the development of a regular monthly pattern of menstruation. These results demonstrate the detrimental effects of ALC on the activation of hormone secretion that accompanies puberty in female rhesus monkeys. They also suggest that the subsequent growth spurt and normal timing or progression of puberty may be at risk in human adolescents and teenagers consuming even relatively moderate amounts of ALC on a regular basis.

Alcohol Drinking↗
PubMed2000

The relation between accommodative facility and general binocular dysfunction.

This study was designed to evaluate the relation between accommodative facility and accommodative and binocular dysfunctions. We determined whether failure to achieve 8 cycles per minute of binocular accommodative facility or 11 cycles per minute of monocular accommodative facility tends to be associated with these dysfunctions. Forty eight subjects, ages 10-30 years were examined and classified into four groups: 13 subjects with accommodative dysfunctions, 11 patients with binocular dysfunctions, 12 subjects with accommodative and binocular dysfunctions and 12 control subjects with refractive errors but no accommodative or binocular anomalies. Monocular and binocular accommodative facility was conducted using +/- 2.00 D flip lenses. In general, statistical analysis indicates that subjects with binocular and accommodative (ocular motor) anomalies performed significantly poorer than subjects of normal group on monocular and binocular facility tests. Monocular accommodative facility results showed more information about the dysfunction of the patient compared with the results of the binocular accommodative facility. In general data supported a relation between reduced accommodative facility and a general binocular dysfunction (accommodative or binocular) which demonstrates the importance of the accommodative facility test in diagnosing an accommodative or binocular anomaly.

Accommodation, Ocular↗
PubMed1999

Effects of ethanol on leptin secretion and the leptin-induced luteinizing hormone (LH) release from late juvenile female rats.

BACKGROUND: Chronic ethanol (EtOH) exposure lowers serum insulin-like growth factor-1 (IGF-1) and luteinizing hormone (LH) levels and also delays female puberty, similar to the deficits in the reproductive system that occur during leptin deficiency. Leptin administration restores fertility and gonadotropin secretion in the ob/ob mouse and can induce recovery of reproductive function in food-restricted animals. This study assessed the effects of EtOH on serum leptin levels, and whether exogenous leptin administration could restore IGF-1 and LH levels in the EtOH-treated animals. METHODS: In the first study, 29-day-old female rats were divided into control and EtOH-treated groups, each of which received their respective diet regimen for 5 consecutive days. The EtOH-treated animals were subdivided and received an intraperitoneal injection of either leptin (100 microg/0.1 ml) or saline twice daily. Control animals also received intraperitoneal saline injections twice daily. On day 34, animals were killed, and serum leptin, LH, and IGF-1 were measured by RIA. In a second study we assessed the acute effects of a single 3 g/kg dose of EtOH on the ability of leptin to act centrally to induce LH release. For this, leptin (1 microg) was administered via a third ventricular (3V) cannula and blood sampling via jugular cannula. In a third experiment, animals were again subjected to a chronic feeding regimen. When 34 days old, they were killed and the anterior pituitaries removed and incubated in a static incubation system for 60 min to establish basal LH release, then for an additional 60 min in medium containing leptin (10(-7) M). RESULTS: Chronic EtOH exposure lowered serum leptin (p < 0.01), IGF-1 (p < 0.01), and LH (p < 0.05) levels. Leptin administration to EtOH-treated animals did not restore serum IGF-1 levels. This peptide did, however, effectively restore LH levels to normal, but did not advance the timing of puberty. Acute EtOH administration was found to block leptin-induced LH release following central administration of the peptide. Conversely, anterior pituitaries from control and 5-day EtOH-treated animals that were incubated in vitro released (p < 0.01) equal amounts of LH in response to leptin (10(-7) M). CONCLUSIONS: These data demonstrate that EtOH administration not only can suppress peripheral levels of leptin, but also blocks its central action to facilitate LH secretion. Although replacement of leptin can reverse the EtOH-induced suppression of LH by a direct action at the level of the pituitary, it cannot elevate serum IGF-1; a peripheral signal that acts centrally to stimulate LH releasing-hormone (LHRH)/LH release during the juvenile-peripubertal transition period, and thus accelerates the initiation of female puberty. These results demonstrate further the complex actions and interactions of multiple hormones involved in the pubertal process and the vulnerability of their actions to the toxic effects of EtOH.

Age Factors↗
PubMed1998

Influence of the smoking habit in the surgery of inflammatory bowel disease.

UNLABELLED: The smoking habit is a key factor in the development of inflammatory bowel disease (IBD), but little information exists as to the relationship between smoking habit, the need of surgery and its complications. OBJECTIVES: To investigate the relationship between smoking habit, the need of surgery, their complications and clinical recurrence after surgery in Crohn's disease (CD) and ulcerative colitis (UC). METHODS: We studied a group of 62 patients (22 with UC and 40 with CD) with previous surgery. We analyzed the clinical and surgical characteristics of the disease. Smoking habit was established by a personal interview. This group of patients was compared with another control group of 202 patients (133 with UC and 69 with CD) with IBD without previous surgery. RESULTS: Smoking habit was similar between operated and non-operated patients for both UC (73% and 80% non-smokers) and CD (67% and 63% smokers) The number and type of complications after surgery were not related with smoking habit. In CD patients, although the recurrences did not depend on the smoking habit, they did occur earlier in smokers than in non smokers (83.6 +/- 21 vs 155 +/- 50 weeks, p = ns). CONCLUSIONS: The smoking habit does not seem to influence significantly the need of surgery and post surgical development of IBD, although in CD the smokers seems to present recurrence before non smokers.

Adult↗
PubMed1997

Fluorouracil and high-dose leucovorin with radiotherapy as adjuvant therapy for rectal cancer. Results of a phase II study.

The purpose of this phase II study was to evaluate the efficacy and toxicity of fluorouracil and high-dose leucovorin (5-FU/LV) with pelvic irradiation as adjuvant therapy for patients with macroscopical resected rectal or recto-sigmoid cancer. Following surgery for stages II-III primary (52) or recurrent rectal cancer (4), 56 patients received 8 cycles of 5-FU/LV and pelvic irradiation. 5-FU doses were 200 mgr/m2 for cycles 2-3 and 300 mgr/m2 for cycles 1 and 4-8. LV doses remained fixed at 200 mgr/m2. Pelvic radiation was started in the third week, between the first and second cycle. The total dose was 50.4 Gy. No severe complications had been recorded. The incidence of grade 3 diarrhea was 19%. Three patients presented leukopenia grade 3 (5%). In 44 patients (78%) the planned treatment could be administered. The median follow-up was 40 months (range 22-66). Seven patients had a local relapse (13%) and 6 developed distant metastasis (10%). The 3-year disease-free survival was 72% and the overall survival was 76%. These preliminary results show that combined post-operative 5-FU/LV and pelvic radiotherapy are well tolerated and present a reasonable local control and survival rates. This adjuvant treatment should be evaluated in randomized trials.

Adult↗
PubMed1995

N-methyl-D-aspartic acid receptor messenger ribonucleic acid levels and luteinizing hormone release in immature female rats: effects of stage of pubertal development and exposure to ethanol.

This research was designed to determine 1) whether changes occur in the levels of N-methyl-D-aspartic acid (NMDA) receptor (NMDA-R) messenger RNA (mRNA) in the reproductive hypothalamus of female rats as they approach puberty, 2) whether NMDA-R stimulation would promote differential LH responses during the specific stages of peripubertal development, and 3) whether ethanol (ETOH), which is known to affect the NMDA-R in other brain systems, can alter NMDA-R-activated LH secretion at puberty. In the first experiment, female rats were killed at 15, 20, 25, and 34-36 days of age to determine the levels of mRNA that code for the NMDA-R, specifically NMDA-R1, in the arcuate nucleus-median eminence (AN-ME) and preoptic area (POA) during pre- and peripubertal development by a ribonuclease protection assay. Results indicate that in juvenile animals, NMDA-R mRNA levels in the AN-ME increased at 25 days (P < 0.01). In the POA, the levels increased at 20 days (P < 0.05), but were unchanged at 25 days. During the peripubertal period, NMDA-R gene expression in the AN-ME did not change; however, gene expression in the POA increased (P < 0.05) during first proestrus, then declined during first estrus. In the second experiment, NMDA-R stimulation with N-methyl-D,L-aspartic acid (NMA; 2.5 mg/kg) produced differential stimulatory effects on LH release depending upon the stage of pubertal development. In this regard, significant post-NMA percent increases in LH released over pre-NMA (basal) levels occurred during anestrus (46%; P < 0.01) and first proestrus (95%; P < 0.01), with nonsignificant increases of 18% and 28% during first estrus and diestrus, respectively. Finally, a 3 g/kg dose of ETOH given intragastrically 90 min before the NMA challenge blocked (P < 0.05) NMA-induced LH release during first proestrus. In conclusion, these findings demonstrate regional differences in the timing of NMDA-R gene expression in the reproductive hypothalamus during pubertal development, show differential responses of LH to NMDA-R activation during the peripubertal period, and continue to demonstrate the vulnerability of the hypothalamic-pituitary axis to the detrimental effects of ETOH at this critical time of development.

Animals↗
PubMed1995

Factors associated with work-related accidents and sickness among maquiladora workers: the case of Nogales, Sonora, Mexico.

The health problems of maquiladora workers were explored in a sample of 497 workers of Nogales, Sonora, Mexico. The workers were interviewed using a structured questionnaire containing four sections: a sociodemographic profile, occupational history, working conditions, and a health profile. Overall, 12.6 percent of the workers reported having an accident while working in the maquila, more than 40 percent of these requiring at least one day of disability, and 18.3 percent of workers reported having an episode of sickness/disease. More than 60 percent perceived health-related risks associated with working conditions. The presence of a doctor or nurse in the plant (odds ratio = 0.30), a perception of risk associated with working conditions (odds ratio = 1.85), and the plant offering information about work-related risks (odds ratio = 0.39) were among the significant predictors of work-related accidents and disease/sickness. The authors discuss the implications of these results for programs and policies to improve safety conditions in the maquiladora industry.

Accidents, Occupational↗
PubMed1982

Transient repression of erythromycin formation in Streptomyces erythraeus.

The effect of a D-glucose on growth and erythromycin production by Streptomyces erythraeus was investigated. D-Glucose stimulated growth and caused a strong but temporary suppression of antibiotic formation. Maximum specific suppression of erythromycin formation occurred at a carbohydrate concentration of 20 mg ml-1. A non-metabolizable analogue of glucose, 2-deoxy-D-glucose, also suppressed antibiotic formation. Since glucose caused a decrease in erythromycin formation only when added before the stage of antibiotic production, we conclude that this sugar exerted a transient repressive effect on erythromycin biosynthesis.

Deoxyglucose↗
PubMedDate not supplied

[Pancreatic phlegmon: a potentially fatal form of acute pancreatitis].

AIM: To report the clinical characteristics of a group of patients with pancreatic phlegmon (PF) seen at the Instituto Nacional de la Nutricion Salvador Zubiran, Mexico City. MATERIAL AND METHODS: We reviewed all the cases of acute pancreatitis hospitalized from January 1981 to December 1989. The diagnosis of pancreatic phlegmon was established when the CT scan showed a solid mass in the pancreas and peripancreatic region with more than 20 Hounsfield units without liquid collections or a fibrous capsule. We analyzed clinical, biochemical, and radiological data. RESULTS: Acute pancreatitis was diagnosed in 132 patients. In 14 a pancreatic phlegmon was observed (10.6%). Twelve were men; the mean age was 44.7 years. In six cases acute pancreatitis was secondary to alcohol abuse and in four to gallstones. Abdominal pain was present in all patients. Ten had leucocitosis and seven fever and/or jaundice. An abdominal mass was detected in three cases. The severity of pancreatitis was graded according to our institutional criteria as mild (0-2 signs) or severe (3-5 signs). In 10 patients AP was graded as mild: no mortality was observed in this group but three presented complications (two liquid collections and one an abscess). The four patients with severe pancreatitis presented complications and three died (one abscess, two multiorgan failure). Five patients were operated on. In three an abscess was drained. CONCLUSIONS: Pancreatic phlegmon is a potentially severe form of AP. All patients who died presented, in addition to PF, clinical criteria of severe pancreatitis.

Acute Disease↗