Biomedical subjects
Publications and source records attributed to G Lopez.
A new method based on surgical removal and chemically induced degeneration of pelvic ganglia in female rats is described. This combined procedure stems from the difficulty to locate the primary and accessory pelvic ganglia.
The relationship between thyroid growth-stimulating antibodies (TGSAb) and thyroid adenylate cyclase-stimulating antibodies (TSAb) in patients with Graves' disease is still a matter of controversy. To investigate this problem, we have developed an assay for the simultaneous measurement of TSAb and TGSAb using FRTL-5 cells. TSAb was detected by its ability to stimulate iodide (I-) uptake and TGSAb by the 3H-thymidine ([3H]-Tdr) incorporation assay. Thirty-four immunoglobulin G (IgG) preparations from patients with active Graves' disease were selected from a previous series in order to include both TSAb-negative IgGs (n = 9) and TSAb-positive IgGs (n = 25) by the cAMP stimulation assay, with a wide range of stimulatory activity. With one exception, the TSAb-positive IgGs produced a significant stimulation of I- uptake; 20 of them were also TGSAb-positive. The nine IgGs negative in the cAMP assay, were also negative in the I-uptake and the [3H]-Tdr incorporation assays. The majority of samples had a similar potency in the two assays and a significant positive correlation was found (r = 0.76; P less than 0.001). Two IgGs previously shown to inhibit TSH-stimulated adenylate cyclase in FRTL-5 cells produced an almost complete inhibition (80-90%) of both TSH- and Graves' IgG-stimulated I- uptake and [3H]-Tdr incorporation. In conclusion, using a simultaneous assay for thyroid growth and adenylate cyclase stimulation, TGSAb in Graves' patients were found only in TSAb-positive IgGs; both Graves' IgG-stimulated activities were inhibited by antibodies blocking the TSH-dependent adenylate cyclase stimulation. Our data strongly suggest that the same antibody may be responsible for both goitre and thyroid hyperfunction of Graves' disease.
FRTL-5 cells were shown to be suitable for the measurement of thyroid stimulating antibody (TSAb) present in sera of patients with Graves' disease. Current methods for the assay of TSAb require the separation of immunoglobulin G (IgG) from patient sera. In this report the possibility to measure TSAb directly on serum was evaluated using FRTL-5 cells. To this purpose cells were seeded in 96-well plates and cultured for 4 days in medium deprived of TSH. Using this system bovine TSH was able to produce a significant stimulation of cAMP production at 1 microU/ml. Whole normal serum completely inhibited the stimulation of TSH as well as that of TSAb, while diluted serum was devoid of any effect. Heat inactivated sera and IgGs, prepared by DEAE Sephadex separation, were diluted in hypotonic medium and incubated with cells for 1 h at 37 C. After incubation cAMP was measured in the assay medium by RIA. In some experiments the effects of graded dilutions of sera and IgGs with known TSAb activity were compared. Sera as well as IgGs increased the cAMP production, but, at the highest concentrations, an inhibitory effect was evident. For this reason sera were tested after appropriate dilution. Thirteen/27 (48%) sera and 22/27 (81%) IgGs from patients with Graves' disease were TSAb positive. The effect of Graves' sera on adenylate cyclase stimulation was completely inhibited by an anti-human IgG. The results of stimulation produced by Graves' sera and IgGs were highly correlated (r = 0.97, p less than 0.001). In conclusion it is possible to measure TSAb directly in serum using FRTL-5 cells.(ABSTRACT TRUNCATED AT 250 WORDS)
Oral antibiotic ingestions account for 1-2% of all pediatric exposures reported to regional poison information centers. The majority of these pediatric exposures involve the ingestion of penicillin or cephalosporin derivatives. How much can be ingested before gastric emptying is necessary is a controversial issue in the management of these cases. A study was designed to determine if children less than 6 years of age could safely ingest a maximum of 250 mg/kg of a penicillin or cephalosporin derivative without significant adverse effects. Sixty-one cases were prospectively collected. The average antibiotic amount ingested was 113.3 mg/kg (17.8-250.0 mg/kg). Each patient was evaluated for symptoms at the time of the initial call and at 6-12 degrees, 24 degrees, 48 degrees, and 72 degrees. Eighty-four percent of the children remained asymptomatic during the evaluation period. Eight of 13 symptomatic patients developed 1 or 2 episodes of diarrhea; 2 developed a rash. Amoxicillin suspension was involved in 70% of the cases, followed by cefachlor suspension 11%, and amoxicillin tablets 5%. Liquid preparations accounted for 90% of the cases and solid dosage forms, the remainder. The data strongly suggests that ingestions of less than 250 mg/kg of these products are not associated with significant outcomes and do not require gastric emptying.
Autoantibodies blocking the TSH-stimulated cAMP production (TBkAb) were measured in immunoglobulin G (IgG) preparations from 38 patients with primary autoimmune hypothyroidism, using FRTL-5 cells. TBkAb were detectable in 15/23 IgG preparations from patients with untreated idiopathic myxedema, and in 2/15 IgGs from patients under L-thyroxine treatment. None of the IgG from 22 normal subjects or from 10 patients with nonautoimmune hypothyroidism following total thyroidectomy caused any significant effect on the TSH-stimulated cAMP production. No correlation was found between TBkAb and the thyroid microsomal antibody. Antibodies inhibiting the 125I-TSH binding to TSH receptor were detectable in only 3/20 patients; IgGs from these 3 patients were also positive in the TBkAb assay. One IgG with potent TBkAb activity inhibited the TSH-stimulated adenylate cyclase in a competitive manner, while it had no effect on the forskolin-stimulated cAMP production. The inhibiting action of this IgG was almost completely lost after preabsorption with human thyroid membranes. In conclusion, we describe a new practical and sensitive method for the measurement of TBkAb; TBkAb are distinct from the microsomal antibody, and are probably directed to the TSH receptor.
Evidence has been accumulated that human thyroid microsomal/microvillar autoantigen (M) is expressed both in the cytoplasm and on the surface of thyroid follicular cells. The availability of this autoantigen to the immune system, possibly associated with abnormally expressed HLA-DR antigens may be relevant both to the triggering and to maintenance of thyroid autoimmune reactions. Preliminary biochemical characterization of M suggested that it was a glycoprotein with a mol. wt. of about 100-110 kD. recent studies carried out in our laboratories taking advantage of monoclonal antibodies provided evidence that the structure presently referred as M-Ag is represented by thyroid peroxidase (TPO). The identity between TPO and M is further supported by four-layer immunofluorescence analysis showing a complete overlap of the two antigens both in the surface and in the cytoplasm of thyroid cells and by the observation that the expression of M and TPO is similarly modulated by TSH, possibly through a cAMP-dependent mechanism.
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A clinical trial of levonorgestrel-releasing Norplant implants used for contraception was undertaken in two cities in Colombia. Through two years in which 389 women had accumulated 594 years of use, there were no pregnancies. In a comparison group of copper intrauterine device acceptors, the one-year pregnancy rate was 1.1 per 100. Menstrual disturbances associated with progestin-only administration were the principal side-effects, and the major reason for cessation of use. Continuation among users of the implants was at the same or at a higher rate than observed among users of the intrauterine device. Advantages and disadvantages of alternate sites for implant placement are discussed.
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Nine patients with chronic renal failure associated with long-standing spinal cord injury were treated with peritoneal dialysis for periods ranging from 3 days to 12 months. Indwelling peritoneal catheters and automated peritoneal dialysis machines were used in the majority of cases. The procedure was generally used as an interim measure while awaiting placement or maturation of the blood access for hemodialysis. Several patients, however, underwent peritoneal dialysis for prolonged periods, including a patient who was on home-peritoneal dialysis for 12 months. The main complications resulting from 653 patient-day treatments consisted of six bouts of peritonitis and a single case of bowel perforation. Azotemia, fluid electrolytes and acid-base status were satisfactorily controlled with peritoneal dialysis. The results were comparable with those obtained during hemodialysis. Peritoneal dialysis, therefore, appears to be a reasonable alternative to hemodialysis in the management of chronic renal failure in spinal cord injured patients.
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The most important determinants of the functional ability of an amputated part are proper patient selection and the recognition of vascular compromise. Ideally, a well-performed anastomosis should need no pharmacologic assistance, but the ideal is often the exception. The authors present an empirical approach to use of anticoagulation medication.
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Anaplasma marginale, Babesia argentina and Babesia bigemina infected blood used as vaccines for immunization trials in Valle del Cauca, were preserved with 4 Molar Dimethyl-Sulfoxide (4M DMSO) and stored in liquid nitrogen (-196 degrees C). The effectivity of the vaccines was determined in 87 healthy calves utilizing serial 10-fold dilutions. The effects of dose, inoculation routes, time and temperature were determined. The minimum infective dose for A. marginale was 10(-3) (2 x 10(6)) when 2 ml of vaccine were given intravenously (i.v.). The same dose when given subcutaneously (s.c.) was not infective. The 10(-2) dilution (2 x 10(7)) was infective when given through both routes, however, the incubation periods were statistically different. The average incubation period using 2 ml s.c. was 30 days, but when the dose was increased to 5 ml and given s.c. the average incubation period decreased to 22 days. The minimum infective doses for b. bigemina and B. argentina were 10(-1) dilutions (4 x 10(-7)) and 10(-2) (4 x 16(6)) respectively, when 2 ml of vaccines were injected i.v.. Infectivity was also recorded when Babesia spp. vaccines were injected s.c. at dosages of 5 ml of dilution 10(-1) (1 x 10(-8)).
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