Biomedical subjects
E Fernandez
Publications and source records attributed to E Fernandez.
Motonuclear changes after cranial nerve injury and regeneration.
Little is known about the mechanisms at play in nerve regeneration after nerve injury. Personal studies are reported regarding motonuclear changes after regeneration of injured cranial nerves, in particular of the facial and oculomotor nerves, as well as the influence that the natural molecule acetyl-L-carnitine (ALC) has on post-axotomy cranial nerve motoneuron degeneration after facial and vagus nerve lesions. Adult and newborn animal models were used. Massive motoneuron response after nerve section and reconstruction was observed in the motonuclei of all nerves studied. ALC showed to have significant neuroprotective effects on the degeneration of axotomized motoneurons. Complex quantitative, morphological and somatotopic nuclear changes occurred that sustain new hypotheses regarding the capacities of motoneurons to regenerate and the possibilities of new neuron proliferation. The particularities of such observations are described and discussed.
Hypoglossal-facial nerve anastomosis.
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[Hepatitis A virus infection in children in Argentina: a pilot study].
UNLABELLED: The severity and/or the prognostic of infections with the hepatitis A virus (HAV) is related to the age at which the infection occurs. Since transmission of the virus occurs by the fecal-oral route, the prevalence and age-relate incidence of infection is determined by the adequacy of sanitation hygienic measures and the socio economic level of exposed populations. Thus, the disease is having an increasing impact in developing countries with improving sanitary standards whereas inhabitants of industrialized countries are particularly at risk while visiting under-developed countries. We have established a cooperative group for the serologic study of children range between six months to ten years old, without sintomatology of acute hepatitis. The patients live in Buenos Aires, San Justo, Trelew, Rosario and Tucumán cities. We studied 3699 children. The specific Ab-antiHAV IgG were measured by enzyme immunoassay with commercial available kits (Organon and-or Abbott). The variable of study were age, sex and water quality. RESULTS: 45.19% were of San Justo, 26.15% of Rosario, 13% of Buenos Aires, 8.37% of Trelew and 7.29% of Tucumán. We observed the highest of possibility percentage (%POS) in Tucumán (81.4%), followed by San Justo (57.8%), Rosario (46.5%), Trelew (41.99%) and Buenos Aires (29.4%). In all the cities the lowest %POS was found in children under three years old. Between three and six years old the results were variable and an increase in %POS was observed related to the growth. The global %POS was 51.56%. CONCLUSIONS: This study confirms Argentina as a high endemic country for HAV infection. A global vaccination program is the only strategy that has the potential to prevent recurrent epidemics of hepatitis A and its erradication.
Alpha-melanocyte stimulating hormone-induced pigmentation is blocked by depletion of protein kinase C.
We have explored the role of protein kinase C (PKC) in pigmentation induced by alpha-melanocyte stimulating hormone (alpha-MSH). Using the well-studied S91 Cloudman mouse melanoma model system in which 10(-7) M alpha-MSH is known to produce a time-dependent increase in pigmentation, we found an increase in the activity of tyrosinase, the key enzyme in pigmentation, between Days 2 and 6 accompanied by an increase in mRNA and protein levels of tyrosinase, as well as an increase in the level of specifically the beta isoform of PKC. When S91 cells were treated with phorbol dibutyrate, 95% of PKC activity was lost within 48 h and the alpha-MSH-induced melanogenesis was completely blocked, as was the induction of tyrosinase mRNA and protein. Serially passaged S91 cells no longer capable of responding to alpha-MSH had an undetectable level of PKC-beta, although the tyrosinase protein level was identical to that of alpha-MSH-responsive cells. Furthermore, in these S91 cells alpha-MSH also did not increase the level of tyrosinase mRNA. Thus, induction of murine melanogenesis by alpha-MSH involves up-regulation of tyrosinase mRNA and protein mediated in part by the PKC-dependent pathway, associated with an up-regulation of the beta isoform previously demonstrated to specifically activate tyrosinase in human melanocytes.
Do we believe what patients say about their neoplastic symptoms? An analysis of factors that influence the interviewer's judgement.
In order to analyze factors that influence an interviewer's judgement of the validity of responses given by patients on the duration of their neoplastic signs and symptoms, 183 consecutive symptomatic patients hospitalized for a digestive tract neoplasm were personally interviewed. The validity of the answers was judged by the interviewers to be high in 156 cases (85%), and low in 27 (15%). The subjective validity of the interview (SVI) was inversely related to the time elapsed from first medical symptom to interview (TFMSI), even after adjusting for the duration of the interview (p < 0.05). SVI was not influenced by whether patient and interviewer agreed on the first symptom. SVI was inversely related to educational level (p < 0.01) and to occupational class (p = 0.04). Patients whose Karnofsky's Index (KI) was > or = 80 were over twice as likely to yield valid responses (TFMSI-adjusted odds ratio [OR] = 2.82, p = 0.037). Multivariate analyses selected education, TFMSI and KI as independent predictors of the interviewer assessment. The SVI of patients admitted to the hospital through the Emergency Department was lower than that of subjects whose admission was planned (OR = 6.49, p = 0.005). In this study SVI related in a logical manner to the characteristics of the interview, of the subjects and of their clinical course. It hence appeared to reasonably estimate the validity of data collected. Identifying factors that affect the reliability of patients' responses would help increase the validity of studies on the duration of cancer symptoms.
Hydrocephalus and macrocrania: surgical or non-surgical treatment of postshunting subdural hematoma?
BACKGROUND: Subdural hematoma is a well-known complication of hydrocephalus shunting procedures. Since the advent of modern neuroimaging techniques, a more realistic incidence of subdural hematomas in shunted patients has been recognized. The description of several asymptomatic cases raises the problem of choosing the most appropriate therapeutic policy for such a condition. METHODS: We report two cases with long standing hydrocephalus and macrocrania in which bilateral huge acute and subacute postshunting subdural hematoma developed and remained asymptomatic. RESULTS: The first patient was treated initially by surgery. Subsequently, despite the persistence of the subdural collections, a nonsurgical policy was chosen. The second patient was deliberately nonsurgically treated. CONCLUSIONS: On the basis of our experience, we conclude that a nonsurgical policy should be followed in patients with long standing hydrocephalus and macrocrania, if they develop postshunting large hemorrhagic subdural collections and remain asymptomatic.
Neurosurgery of the peripheral nervous system--Part I: basic anatomic concepts.
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Laboratory determinations in Anisakis simplex allergy.
BACKGROUND: Anaphylactic reactions caused by the fish nematode, Anisakis simplex, after ingestion of parasitized fish, have been described. OBJECTIVE: This study was undertaken to confirm, by histamine release tests, that A. simplex is able to trigger IgE-mediated reactions and to describe the serologic profiles in this sensitization. METHODS: Twelve patients who had anaphylactic symptoms after ingestion of cooked fish and positive prick test results and determinations of IgE to A. simplex were studied by indirect IgG ELISA and IgG and IgE immunoblotting. Sera from subjects parasitized with other nematodes, patients with fish allergy, and healthy donors were included as controls. A histamine release test was performed in a representative case. RESULTS: IgE immunoblotting was a specific test to detect A. simplex allergy. IgE-reacting bands were found in serum samples from 11 of our patients. Specific IgG antibodies were found by ELISA and immunoblotting, but this response was less specific. Histamine release was positive with A. simplex extract and negative with fish. CONCLUSION: A specific and intense immune response to an A. simplex extract was found in our patients. A. simplex is able to elicit anaphylactic reactions, and A. simplex allergy should be suspected in patients with allergic symptoms after ingestion of fish. A positive prick test response to A. simplex and a negative response to fish is a good indication for a diagnosis of A. simplex allergy.
Reversal of muscle fatigue in intact rabbits by intravenous potassium chloride.
PURPOSE: Skeletal muscle fatigue has been associated with potassium efflux from the myocytes, resulting in endogenous increases in blood potassium concentration ([K+]). Conversely, exogenous increases in extracellular [K+] potentiates contraction in isolated muscle preparations. The mechanisms responsible for these contradictory effects of [K+] on skeletal muscle function are unknown. Moreover, little is known about the effect of exogenous increases in [K+] on force generation by intact animals, given potassium's deleterious effect on cardiac function. METHODS: We compared the response to exogenous increases in blood [K+] in rabbits given an infusion of potassium chloride (KCl) intravenously (IV) (0.2 mol/L; KCl group; n = 7) to a group given 0.9% sodium chloride (NaCl) (control; n = 7). The rabbits underwent low-frequency, isometric twitch stimulation of the left hindlimb (square wave pulses 100 microseconds, 40V, 0.25 Hz) throughout the experiment. Both groups received 0.9% NaCl (25 mL/h) during the first hour of twitch stimulation and experienced similar decreases in hindlimb forces to 70% of initial force. A continuous infusion of KCl or of saline (60 mL/h) was started, and hindlimb stimulation continued for 2 hours. RESULTS: There were no changes in [K+] in the control group, and twitch forces progressively declined during the next 2 hours (369 +/- 47 g to 279 +/- 34 g, P < .01). Arterial [K+] increased in the KCl group from 2.6 +/- 0.1 to 10.1 +/- 0.5 mmol/L (P < .01), and hindlimb twitch forces almost doubled (418 +/- 49 g to 756 +/- 55 g, P < .01). Force frequency curves showed improved contractility in the KCl group at stimulation frequencies below 30 Hz. CONCLUSIONS: Exogenous increases in blood [K+] potentiate skeletal muscle contraction in intact animals and reverse low-frequency twitch fatigue. A possible mechanism may be the maintenance of intracellular [K+] by hindering K+ efflux from skeletal muscle cells.
Comparison of Ultrasonography and Hysteroscopy in the Diagnosis of Intrauterine Lesions in Infertile Women
Transvaginal ultrasound is a noninvasive diagnostic technique that remains to be proved as accurate as hysteroscopy in the diagnosis of benign intrauterine lesions. We compared its efficacy with that of hysteroscopy in the diagnosis of benign intrauterine pathology in 126 infertile women in whom the diagnosis was confirmed by histologic studies. The women had a complete evaluation with preoperative transvaginal ultrasound, hysteroscopy, and histologic analysis of uterine cavity specimens. Sensivity, specificity, and predictive values were calculated for ultrasound and hysteroscopy considering the histologic study as 100%. Sensivity was 95% and 100%, and specificity 97.4% and 93.7% for transvaginal ultrasound and hysteroscopy, respectively. The positive predictive value for benign intrauterine lesions was 100% for ultrasound and 89.8% for hysteroscopy. The most frequent intrauterine lesions found were polyps and myomas. Transvaginal ultrasound is a valuable method of diagnosing benign intrauterine lesions in infertile women, and is especially important as a noninvasive technique to plan hysteroscopic surgery.
Total Laparoscopic Hysterectomy
We analyzed our experience with laparoscopic hysterectomy and determined the most important factors that made it safe and reproducible. From January 1, 1994, to March 30, 1996, 68 laparoscopic hysterectomies were performed. The most frequent indication was uterine myomas. Average operating time decreased over the years from 6 hours in 1994 to 1.5 hours in 1996. The most important reasons for the long surgery time were surgeons' skills, uterine size, posterior wall leiomyomata, presence of adhesions, history of cesarean section, presence of deep infiltrating endometriosis with obliteration of the cul-de-sac, and equipment failure. We had no major intraoperative complications, except for a bladder injury in a woman who had had two cesarean sections, which was diagnosed and immediately repaired laparoscopically. Continuous training in endoscopic surgery, especially learning how to dissect the pelvic organs, the development of a trained team, adequate equipment, and appropriate patient selection were among the most important factors that allowed us to reach a safe level in performing this procedure.
Hysteroscopic Correction of Cesarean Section Scars in Women with Abnormal Uterine Bleeding
Abnormal postmenstrual uterine bleeding may occur in women with history of cesarean section. To study the etiology of this anomaly, transvaginal ultrasound (TVU) was performed during follicular phase in 20 such patients, and hysteroscopy in 7. The TVU revealed the presence of fluid in the isthmus in relation to the cesarean section scar, where a kind of pouch or bursa was observed. Cervical introduction of a catheter showed that the fluid was blood. The TVU observation was confirmed in women in whom hysteroscopy was performed. Resection of ring-shaped fibrotic tissue on the inferior part of the scar stopped abnormal bleeding. Four women were infertile and two conceived, probably because stopping postmenstrual bleeding could interfere with the quality of cervical mucus. These findings suggest that abnormal uterine bleeding in women with an abnormal uterine scar could be resolved by minimally invasive endoscopic surgery, and TVU is a valuable diagnostic tool.
Second-Look Microlaparoscopy
Second-look laparoscopy performed a short time after corrective surgery to determine reproductive function has always been controversial. The need for general anesthesia and additional abdominal wall trauma make it unpopular. However, postponing pelvic evaluation after the original surgery results in a large proportion of women attempting pregnancy with deformed anatomy as the result of reformation of pelvic adhesions. Since November 1995 we performed microlaparoscopy for a second look in 20 patients. Original procedures were performed for endometriosis, salpingo-oophorolysis, tubal repair, and complicated ectopic pregnancy. Six of the women had adhesions that interfered with fertility and were referred to an assisted reproduction technology (ART) program. Procedures lasted 14 minutes (range 10-17 min). We encountered no complications. Patients were discharged after 2 hours of recovery and resumed normal activity. Second-look microlaparoscopy can be an important tool in assessing the efficacy of reconstructive reproductive surgery, and in accelerating referral to ART programs in women with poor results.
Oral contraceptives, hormone replacement therapy and the risk of colorectal cancer.
The relationship between oral contraceptives (OCs), menopausal hormone replacement therapy (HRT) and the risk of colorectal cancer was investigated in a case-control study conducted in northern Italy between 1985 and 1992 on 709 women with incident colorectal cancer and 992 controls admitted to hospital for a wide spectrum of acute, non-neoplastic, non-digestive tract, non-hormone-related disorders. A reduced risk of colorectal cancer was observed in women who had ever used OCs [multivariate odds ratio (OR) = 0.58; 95% confidence interval (CI): 0.36-0.92]. The OR was 0.52 (95% CI 0.27-1.02) for use over 2 years. For women ever using HRT, the multivariate OR was 0.40 (95% CI 0.25-0.66). The risk was inversely related to duration of use, with ORs of 0.46 for 2 years or less and 0.25 for more than 2 years of use. No consistent pattern of trends was observed with time since first or last use. This study provides further evidence that OC and HRT do not increase, and possibly decrease, the risk of colorectal cancer. These results, if confirmed, would have important implications for the ultimate risk-benefit assessment of female hormone preparations.
Descriptive features and causal attributions of headache in an Australian community.
The reported characteristics and causes of headache differ across individuals and between groups. Such differences are of interest from an epidemiological point of view. This study set out to identify the main descriptive features and causal attributions of headache within an Australian urban community. A sample of 261 subjects reporting headache volunteered to participate in the survey. Subjects completed a self-report questionnaire for assessing demographic variables, headache parameters (intensity, duration, etc), headache medication habits, and perceived causes of one's headache (as in the UK headache survey by Blau, 1990). Results revealed that the typical headache sufferer was a middle-aged employed individual. Migraine versus tension headache were equivalent in number, and on the average, subjects experienced moderate intensity, day-long headaches that recurred about nine times per month. With regard to causal attributions, the prevalence of headaches due to mental stress was higher than that due to any other single stimulus (eg, noise, exercise), and alcohol was the most frequent dietary cause of headache. These findings are generally consistent with those from previous surveys, although some interesting departures emerge which may be accounted for by demographic differences in the populations studied.
Guidelines for dosing of intravenous calcitriol in dialysis patients with hyperparathyroidism.
Intravenous calcitriol has not been used appropriately in the treatment of secondary hyperparathyroidism (HPT) of dialysis patients. Initiation of calcitriol therapy late in severe HPT and inappropriate dosing of calcitriol are common causes of inadequate use of calcitriol. This paper gives general guidelines on the use of intravenous calcitriol and emphasizes the importance of appropriate control of serum phosphorous. The issue of dosing of calcitriol commensurate with the severity of the HPT are highlighted as essential for the complexion of a successful therapeutic attempt. In addition, maintenance dose of calcitriol varies according to the severity of the HPT at the time of initiation of therapy.
Reclassification and rescaling of McGill Pain Questionnaire verbal descriptors of pain sensation: a replication.
OBJECTIVES: This study was designed to test the stability of recent findings by the authors showing that 40% of the McGill Pain Questionnaire (MPQ) descriptors of pain sensation were not classifiable in any MPQ subcategory because of incomprehension, underuse, or ambiguity of usage. The study also was intended to determine the pain intensity ratings for the descriptors and how they relate to the original ratings provided by Melzack and Torgerson. METHODS: The sample size was twice that of the previous sample; 140 subjects (whose first language was English) assigned MPQ descriptors to individual sensory subcategories and then rated their implied intensity of pain. As in the first study, data were analyzed by a three-step decision rule incorporating the absolute frequency, relative frequency, and distribution of word assignments to the subcategories. Subjects were undergraduate students in a health psychology class at Southern Methodist University. RESULTS: Twenty-eight of the 32 words retained in the first study also satisfied criteria for inclusion in the present study, and four additional words that were not included in the first study satisfied the decision rule in the present study. As in the first study, intensity ratings of retained words correlated very highly with those reported by Melzack and Torgerson. CONCLUSION: A parsimonious set of 32 words can be adopted from the MPQ for efficient and unambiguous use in the clinical assessment of pain.