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Biomedical subjects

Guillermo García-Ramos

Publications and source records attributed to Guillermo García-Ramos.

12 recordsLinked to original sources
PubMed2005

Demographic, clinical and comorbidity data in a large sample of 1,147 patients with migraine in Mexico City.

The objective was to identify the sociodemographic and clinical characteristics of a large sample of patients with migraine in Mexico City. This cross-sectional study was performed in two tertiary centers in Mexico City and affiliated hospitals. We evaluated the presence of migraine through a standardised interview according to the criteria of the International Headache Society. We studied 1,147 patients. The mean age was 37.1+/-13.6 (6-77) years. Nine hundred and twenty one patients were female (80%). The age of onset of migraine was 19.4+/-10.3 (1-69) years. Six hundred and four patients had migraine with aura (53%) and 543 without aura (47%). The female/male ratio was 4:1. One hundred and forty-seven patients had cardiovascular problems (13%), 72 had neurological problems (6%), 233 had gastrointestinal problems (20%) and 323 had psychiatric problems (28%). In this study we described the clinical characteristics of a large sample of patients with migraine in Mexico City. Our sample has similar characteristics to other countries.

Adult↗
PubMed2004

Sympathetic co-activation of skin blood vessels and sweat glands.

Skin blood vessels and sweat glands are both innervated by sympathetic C fibers. We investigated whether during diverse respiratory maneuvers the vasomotor responses (VRs) and the sympathetic skin responses (SSRs) were frequently or occasionally co-activated. We simultaneously recorded the amplitude of the vasomotor responses and the sympathetic skin responses, the ECG and the respiratory movements in 30 healthy subjects during natural breathing at rest, rhythmic respirations at 6 per minute, sudden deep inspiration and Valsalva maneuver. We found: 1) The SSR habituates with all respiratory maneuvers whereas the VRs do not habituate. 2) There was slight co-activation between the SSRs and VRs during natural default breathing (56 percent). 3) During rhythmic breathing at 6 per minute the VRs and the SSRs were frequently co-activated (97 percent). The SSR appeared at the end of the inspiration coinciding with the end of the decreased blood flow. However the SSR habituated after few rhythmic respirations. 4) During sudden deep inspiration one hundred percent of co-activations were between the initial phase of the VRs and the SSR. The SSR is large in amplitude and longer in duration than during rhythmic breathing. 5) During the Valsalva maneuver there was a strong co-activation (100 percent) particularly during the phases II and III that are characterized by vaso-constriction but also during phase IV. The SSR is the longest of duration in all of the maneuvers. The sympathetic innervation to the sweat glands of the palm of the hand and to the skin blood vessels of the fingertips is differentiated. Under normothermic conditions sudden deep inspiration and Valsalva maneuver induced a large sympathetic simultaneous outflow to the skin blood vessels and sweat glands. The simultaneous recording of skin blood flow and the SSRs provides a more complete assessment of the sympathetic outflow to the skin than either one alone.

Adolescent↗
PubMedDate not supplied

Thymectomy in myasthenia gravis: response, complications, and associated conditions.

BACKGROUND: Thymectomy is considered the most effective treatment for achieving sustained improvement as well as remission in patients with myasthenia gravis (MG), and most neurologists favor the use of this procedure. The main focus of many current studies is to determine response-predicting factors. METHODS: Clinical records of 152 patients with an established diagnosis of MG who underwent thymectomy at our institution were reviewed. The purpose was to evaluate outcome of surgical management for MG and prognostic factors that influence that outcome. RESULTS: The majority of patients were women (119 of 152); mean age was 32.10 +/- 14.42 years, while time elapsed from diagnosis to surgery was 20.67 +/- 19.7 months. Transsternal thymectomy was performed on 113 patients and transcervical on 39. Forty percent of patients achieved remission and 28% showed improvement; with this, a good response to thymectomy was seen in 68% of patients (n = 103). The most important variables associated with remission were <60 years of age, <2 years of preoperative symptoms, and use of pyridostigmine at low doses. Factors related with poor response were >60 years of age, preoperative Osserman stage other than II, use of high doses of pyridostigmine, use of corticosteroids, and presence of thymic atrophy or thymoma in histopathologic analyses. There was no mortality, although 20 patients (13%) presented complications. CONCLUSIONS: Mexican patients with MG undergoing thymectomies show improvement and remission rates similar to those reported by other studies. Age, length of symptoms, thymic pathology, and medications appear to be predictors of response to thymectomy for MG.

Adolescent↗
PubMedDate not supplied

Effect of bariatric surgery on obstructive sleep apnea and hypopnea syndrome, electrocardiogram, and pulmonary arterial pressure.

BACKGROUND: We evaluated the impact of surgically-induced weight loss on Obstructive Sleep Apnea/Hypopnea Syndrome (OSAHS), electrocardiographic changes, pulmonary arterial pressure and daytime sleepiness in morbidly obese patients. METHODS: 16 women and 13 men (n=29) underwent bariatric surgery in a 3-year period. The following tests were performed before and 1 year after surgery: nocturnal polysomnography, daytime Multiple Sleep Latency Test (MSLT), and echocardiogram. RESULTS: Mean age was 37.9+/-11 years (range 20-56). Preoperative body mass index was 56.5+/-12.3 kg/m(2) and it was 39.2+/-8.5 kg/m(2) at 13.7+/-6.6 months follow-up. Performed surgical procedures included: vertical banded gastroplasty in 6, Roux-en-Y gastric bypass in 12, and Distal Roux-en-Y gastric bypass in 11. Weight loss induced by surgery eliminated OSAHS in 46% of obese patients with an important improvement in oxygen saturation. Neck, thorax, waist and hip circumferences decreased significantly after surgical intervention but only neck circumference correlated significantly with the apnea/hypopnea index (Spearman rho=0.63, P <0.0001). Electrocardiographic abnormalities were present in 9 patients (31%) before surgery (sinus arrhythmia, ventricular arrhythmias, and sinus arrest). The number of electrocardiographic abnormalities decreased after surgery but new abnormalities appeared in some patients. Systolic pulmonary arterial pressure significantly decreased in the group of patients in whom OSAHS disappeared after surgery. Daytime sleepiness persisted after surgery in most patients. CONCLUSION: Bariatric surgery effectively reduces respiratory disturbances during sleep and improves pulmonary hypertension. Electro cardiographic abnormalities change after surgery. Daytime sleepiness appeared not to be related to respiratory disturbances during sleep.

Adult↗
PubMedDate not supplied

[Effect of muscle contraction on heart rate and skin blood flow. Preliminary results].

Evaluation of heart rate variability is an important tool to study several diseases. The most important tests include the variability of the heart rate as a function of time and as function of frequency, variability of blood pressure and pulsatile cutaneous blood flow (PCBF). We studied the effect of a sustained contraction of the quadriceps muscle on the instantaneous heart rate and pulsatile cutaneous blood flow in 10 healthy subjects. We measured the R-R interval and the instantaneous heart rate, in the time domain, 10 beats before the contraction, the R-R interval that coincided with the onset of the contraction, and the 30 R-R intervals after the beginning of the contraction. To measure the PCBF we used a photopletismograph designed for this purpose. We recorded the surface electromyographic activity (EMG) of the quadriceps muscle to determine the onset and end of the muscle contraction, and measured respiratory movements with a belt. We found an increase of the instantaneous heart rate at the first and second beats after the onset of the contraction. There was a decrease of the pulsatile cutaneous blood flow of the finger pad immediately after the contraction, which lasted for approximately eight beats. The findings support the idea of a central command and co-activation of the motor and sympathetic nervous systems. This efferent sympathetic activity seems to act not just on the contracting muscle but also on the heart and the cutaneous blood vessels of the extremities. These findings imply that it is quite likely that the sympathetic efferent effect has a supraspinal origin. This is a test that could be used to study cardiovascular control by the sympathetic nervous system.

Adult↗
PubMedDate not supplied

Abnormal SPECT myocardial perfusion imaging during periods of obstructive sleep apnea in morbid obese patients without known heart disease.

OBJECTIVE: Determine the myocardial perfusion characteristics in obstructive sleep apnea and its possible role in cardiovascular damage. METHODS AND PROCEDURES: Fourteen patients from the Obesity Clinic weighing less than 130 kg underwent myocardial perfusion studies using single photon emission computed tomography with technetium 99m-labeled sestamibi during nighttime polysomnographic recordings. Coronary angiograms were performed on patients with suspect of severe coronary obstruction according nighttime myocardial perfusion studies or pharmacological stress carried out during waking hours. RESULTS: All 14 patients manifested myocardial perfusion defects during sleep, affecting an average of 5.5 segments/patient, although only 8 presented ischemic ST segment changes and none demonstrated rhythm or conduction disturbances. Angiographic examination of the 10 patients with the most severe perfusion defects did not reveal significant coronary obstruction, and fewer perfusion defects were documented during daytime scintigraphy. DISCUSSION: In obese patients with obstructive sleep apnea, myocardial perfusion defects appear to occur with highest frequency and severity during nighttime sleep, justifying further investigation in a larger number of patients with obstructive sleep apnea and more significant obesity.

Coronary Circulation↗
PubMedDate not supplied

[Response to thymectomy in patients with thymoma].

INTRODUCTION: Approximately 10% of patients with myasthenia gravis also have thymomas. The objective of this study was to describe the evolution after the thymectomy in 10 cases of myasthenia gravis associated with thymomas. METHODS: The study was based in a cohort of 132 patients with the diagnosis of myasthenia gravis, that underwent thymectomy between 1987 and 1997, and had at least three years of follow-up. We found 10 cases (7%) of thymomas. We analyzed the following variables: sex, age, associated diseases, disease evolution, Osserman, dose of edrophonium before surgery, steroid use before surgery, types of thymectomy, Osserman after surgery, pathology findings, and evolution. We used descriptive statistics according to the measurement level of the variables. RESULTS: Four (40%) were women and 6 (60%) were men. The antibodies against the acetylcholine receptor were tested in only 5 (50%) patients, and in all of them they were positive. 4 (40%) patients had complications after the thymectomy, being 2 (20%) of them myasthenic crisis, one (10%) pneumonia and another (10%) hemorrhage in the surgical wound. Six (60%) cases had malignant thymomas and 4 (40%) were benign. In the follow-up, 4 (40%) patients had a good clinical response of myasthenia gravis and 6 (60%) had no changes. CONCLUSION: The response to thymectomy was not as good as the response of the vast majority of patients with myasthenia gravis without thymomas. We found a high frequency of malignant thymomas in our patients.

Adult↗
PubMedDate not supplied

[Secondary Raynaud's syndrome: skin blood flow decrease between the ischemic episodes and prolongation of the vasoconstriction during the respiratory maneuvers].

UNLABELLED: The Raynaud's syndrome is an episodic skin ischemia manifested by pallor, cyanosis and erythema of the fingers in response to cold or emotional stress. The exact pathophysiology is unknown but it has been hypothetised that may be due to an autonomic alteration in the sympathetic innervation of skin blood vessels. OBJECTIVE: To study the changes of heart rate and skin blood flow (SBF) in healthy subjects and in patients with secondary Raynaud's syndrome during different respiratory maneuvers: 1. spontaneous respiration; 2. rhythmic respirations (RR), 3. sudden inspirations (SI), and 4. Valsalva maneuver (VM). METHODS: We studied 22 healthy subjects and 22 patients with secondary Raynaud's syndrome. The variables measured were: 1) RR intervals; 2) amplitudes of SBF; 3) percentage of decrease of SBF; 4) latency of the maximum decrease of SBF. RESULTS: In all patients with secondary Raynaud's syndrome the SBF was decreased basally during spontaneous rations and during all respiratory maneuvers (p < 0.001). The mean latency of recovery of the SBF was prolonged during sudden deep inspiration. The patients with Raynaud also had significant basal tachycardia at rest (p < 0.003). CONCLUSIONS: The basal skin blood flow during spontaneous respirations and in asymptomatic periods is decreased in patients with Raynaud's syndrome; this may be related to endothelial arterioral damage. The SBF was also significantly decreased dynamically during sudden inspirations (SI), rhythmic breathing (RR) and Valsalva maneuver (VM). This dynamic change suggests sympathetic hyperactivity.

Adult↗
PubMedDate not supplied

[Practice guidelines for neuropathic pain management].

UNLABELLED: Neuropathic pain (NP) is a heterogeneous entity with wide diversity of symptoms. Despite the controversies regarding its definition and classification, which difficult its epidemiology, it has been estimated that 4 million people, in USA develop NP. OBJECTIVE: A task force was created to generate a series of recommendations which facilitate the decision making and therapeutic approach of this kind of pain. METHOD: A search of medical literature was made in different electronic data bases (MEDLINE, EMBASE, COCHRANE); after this search we conducted three work-sessions and evaluated the evidence regarding the diagnosis and treatment of pain in painful diabetic poli-neuropathy, post-herpetic neuralgia, and trigeminal neuralgia were evaluated. RESULTS: We found 329 documents for further analysis, and with the aid of the literature results we generate this practice guidelines.

Diabetic Neuropathies↗
PubMedDate not supplied

Efficacy of oral L-ornithine-L-aspartate in cirrhotic patients with hyperammonemic hepatic encephalopathy. Results of a randomized, lactulose-controlled study.

Despite steady progress in therapeutics of liver disease, portal systemic encephalopathy remains to be a great challenge for clinicians because of the heterogeneity of neuropsychiatric symptoms, multiple risk factors and complexity on achieving a sustained response. We aimed to evaluate the efficacy of L-Ornithin, L-Aspartate versus lactulose in Mexican patients with hyperammonemic hepatic encephalopathy. A total of 20 patients were randomly allocated to receive either lactulose(n = 10) or L-ornithine - L-aspartate (n = 10) for 2 weeks. At baseline, patients of both groups were comparable in age (64 +/- 7 versus 60 +/- 6) and degree of hepatic failure according to the Child-Pugh scale (9.2 +/- 1.3 versus 9.2 +/- 1.1). A significant decrease in ammonia levels was observed both in the lactulose group (120.4 +/- 8.1 versus 91.4 +/- 10, p < 0.05) and in the LOLA group (141.6 +/- 9.1 versus 96.9 +/- 9.3, p < 0.05). Moreover, in patients who received LOLA a significant improvement was observed in mental status (1.0 +/- 0.14 versus 0.4 +/- 0.16, p < 0.05), Number Connection Test (184 +/- 43 versus 88 +/- 7, p < 0.05), asterixis (14.6 +/- 2.8 versus 6.7 +/- 1.5, p < 0.05), as well as EEG findings (6.8 +/- 0.6 versus 8.1 +/- 0.2 cycles per second, p < 0.05). Compliance with study medications was similar between the lactulose group (94%) and the LOLA group (100%). No serious adverse events were reported in the two groups; however, in the lactulose group an increase in the number of weekly defecations was reported, as well as a higher incidence of abdominal pain or flatulence. Finally, both patient groups reported an improvement in the Visual Analogue Scale for EuroQol index (51.1 +/- 24.1 versus 61.5 +/- 15.8, p < 0.05, in the lactulose group; 56.5 +/- 24.5 versus 70 +/- 19.4, p < 0.05, in the LOLA group). In conclusion, oral administration of lactulose or L-ornithine - L-aspartate to Mexican patients with cirrhosis and hyperammonemic encephalopathy significantly reduced serum ammonia levels in study groups and additionally improved mental status parameters, number connection test, asterixis scores, and EEG activity in the group receiving L-ornithine-L-aspartate.

Administration, Oral↗