Una Visión desde el Exterior / A view from abroad

Desde febrero de 2001, la doctora Tatiana Botero profesora asociada de la Facultad de Odontología se encuentra trabajando como profesora visitante en la Facultad de Odontología de la Universidad de Michigan en Ann Arbor donde ha trabajado en el grupo de investigacion liderado por el doctor Jacque Nor, con quien recientemente presento en el Congreso de la IADR su trabajo “Bacterial LPS Enhances VEGF Expresión in dental Pulp Cells and Macrophages”. Después de más de 18 meses, la doctora Botero nos presenta una perspectiva de nuestra situación académica vista desde el exterior teniendo en consideración su destacada trayectoria académica en nuestro medio.

Proposed diagnostic criteria for neurocysticercosis.

Neurocysticercosis is the most common helminthic infection of the CNS but its diagnosis remains difficult. Clinical manifestations are nonspecific, most neuroimaging findings are not pathognomonic, and some serologic tests have low sensitivity and specificity. The authors provide diagnostic criteria for neurocysticercosis based on objective clinical, imaging, immunologic, and epidemiologic data. These include four categories of criteria stratified on the basis of their diagnostic strength, including the following: 1) absolute--histologic demonstration of the parasite from biopsy of a brain or spinal cord lesion, cystic lesions showing the scolex on CT or MRI, and direct visualization of subretinal parasites by funduscopic examination; 2) major--lesions highly suggestive of neurocysticercosis on neuroimaging studies, positive serum enzyme-linked immunoelectrotransfer blot for the detection of anticysticercal antibodies, resolution of intracranial cystic lesions after therapy with albendazole or praziquantel, and spontaneous resolution of small single enhancing lesions; 3) minor--lesions compatible with neurocysticercosis on neuroimaging studies, clinical manifestations suggestive of neurocysticercosis, positive CSF enzyme-linked immunosorbent assay for detection of anticysticercal antibodies or cysticercal antigens, and cysticercosis outside the CNS; and 4) epidemiologic--evidence of a household contact with Taenia solium infection, individuals coming from or living in an area where cysticercosis is endemic, and history of frequent travel to disease-endemic areas. Interpretation of these criteria permits two degrees of diagnostic certainty: 1) definitive diagnosis, in patients who have one absolute criterion or in those who have two major plus one minor and one epidemiologic criterion; and 2) probable diagnosis, in patients who have one major plus two minor criteria, in those who have one major plus one minor and one epidemiologic criterion, and in those who have three minor plus one epidemiologic criterion.

Lipid profile in congenital adrenal hyperplasia.

Glucocorticoids have been reported to exert a marked effect on lipoprotein metabolism. Several studies have shown a potential risk of hyperlipidemia in patients under long-term glucocorticoid therapy. Current management of patients with congenital adrenal hyperplasia (CAH) includes the use of glucocorticoids to attenuate the increased production of undesirable adrenal hormones. A case-control study was designed to compare the serum lipid profiles of 14 patients with CAH under glucocorticoid therapy and 14 normal controls and to determine the characteristics of the profiles. A total of 9 patients (64.3%) had serum total cholesterol (TC) greater than 4.4 mmol/L (170 mg/dL), compared with 6 individuals in the control group (42.3%). Nine patients with CAH (64.3%) had serum triglycerides (TGs) more than 1.0 mmol/L (90 mg/dL), compared with only 2 in the control group (14.3%). Similarly, the mean serum TG was higher in the CAH group versus the controls, 1.33 mmol/L (118 mg/dL) versus 0.75 mmol/L (67 mg/dL), respectively. Serum low-density lipoprotein, (LDL-C) and high-density, lipoprotein (HDL-C) cholesterol were determined in 13 children with CAH and in the 14 controls. Nine CAH patients (69.2%) and 8 controls (57%) had LDL-C greater than 2.8 mmol/L (<110 mg/dL). For HDL-C, 2 children with CAH (15.4%) and 4 controls (28.6%) had levels less than 0.9 mmol/L (35 mg/dL). There were no significant differences for the cholesterol index, 0.24 for the controls and 0.22 for the CAH group. In the CAH group, the mean serum TG level and the percentage of individuals with TGs greater than 1.0 mmol/L were statistically significant compared with the controls. The mean serum TC and LDL-C, as well as the percentage of subjects with levels over the cutoff point, although slightly higher in the CAH group, were of no statistical significance. The results of this pilot study suggest that long-term glucocorticoid therapy in patients with CAH may induce abnormalities in the serum lipid profile characterized mainly by an increment in serum TGs.

A proposal to declare neurocysticercosis an international reportable disease.

Neurocysticercosis is an infection of the nervous system caused by Taenia solium. It is the most important human parasitic neurological disease and a common cause of epilepsy in Africa, Asia, and Latin America, representing enormous costs for anticonvulsants, medical resources and lost production. Neurocysticercosis is a human-to-human infection, acquired by the faecal-enteric route from carriers of intestinal T. solium, most often in areas with deficient sanitation. Intestinal tapeworms cause few symptoms, but adult taeniae carried by humans release large numbers of infective eggs and are extremely contagious. Ingestion of poorly cooked pig meat infested with T. solium larvae results in intestinal taeniosis but not neurocysticercosis. With a view to hastening the control of taeniosis and neurocysticercosis we propose that neurocysticercosis be declared an international reportable disease. New cases of neurocysticercosis should be reported by physicians or hospital administrators to their health ministries. An epidemiological intervention could then be launched to interrupt the chain of transmission by: (1) searching for, treating and reporting the sources of contagion, i.e. human carriers of tapeworms; (2) identifying and treating other exposed contacts; (3) providing health education on parasite transmission and improvement of hygiene and sanitary conditions; and (4) enforcing meat inspection policies and limiting the animal reservoir by treatment of pigs. We believe that the first step required to solve the problem of neurocysticercosis is to implement appropriate surveillance mechanisms under the responsibility of ministries of health. Compulsory notification also has the major advantage of providing accurate quantification of the incidence and prevalence of neurocysticercosis at regional level, thus permitting the rational use of resources in eradication campaigns.

Intrauterine growth retardation and long-term effects on growth.

The authors present intrauterine growth retardation (IUGR) as an entity with significant prevalence, morbidity, and mortality. They discuss short-term and long-term sequelae, and particularly emphasize long-term growth disabilities. The authors review the most important trials with human growth hormone that have been carried out recently to maximize the growth and final height potential of children affected with IUGR. They also highlight the most recent advances in the field of fetal growth, with special attention to genetic and endocrine factors. Finally, the authors discuss in detail epidemiological and clinical evidence of the causes of IUGR in relation to several adult onset disorders.

Bioassay of thyrotropin receptor antibodies with Chinese hamster ovary cells transfected with recombinant human thyrotropin receptor: clinical utility in children and adolescents with Graves disease.

OBJECTIVE: The objective of this study was to compare the clinical utility of a new bioassay for thyrotropin (TSH) receptor antibodies (Abs) with the conventional radioreceptor assay and with measurement of thyroid peroxidase Abs in the diagnosis of Graves disease in childhood. STUDY DESIGN: Serum samples obtained from 22 children and adolescents with Graves disease (19 hyperthyroid, 3 in remission), 13 children and adolescents with chronic lymphocytic thyroiditis, and 17 normal children in a control group were evaluated. RESULTS: TSH receptor Abs were detected by bioassay in 10 (91%) of 11 patients with active Graves disease but in 0 of 2 patients in remission, 0 of 13 normal members of the control group, and 0 of 11 patients with chronic lymphocytic thyroiditis including 1 with thyrotoxicosis. The sensitivity and specificity of TSH receptor Abs detected by radioreceptor assay studied in the same 11 patients and in an additional 11 patients was similar to bioassay. In contrast, thyroid peroxidase Abs were detected in only 12 (71%) of 17 patients with Graves disease but in 11 of 11 patients with chronic lymphocytic thyroiditis and in 0 of 17 members of the control group. CONCLUSION: Bioassay of TSH receptor Abs is both sensitive and specific for the diagnosis of active Graves disease in the young. When cost and simplicity are considered, however, bioassay offers no advantage over radioreceptor assay for initial diagnostic screening. Rather, bioassay for TSH receptor Abs may be useful in thyrotoxic patients who are negative initially in the radioreceptor assay or in treated patients whose clinical picture is discordant with results in the radioreceptor assay.

Incidence of transient congenital hypothyroidism due to maternal thyrotropin receptor-blocking antibodies in over one million babies.

To determine the incidence of transient congenital hypothyroidism due to TSH receptor-blocking antibodies, we screened dried blood specimens obtained from 788 neonates identified as having possible congenital hypothyroidism (from a total population of 1,614,166 babies) and 121 controls. A RRA was used. The potency of blood spot TSH binding inhibitory activity was compared with the severity of congenital hypothyroidism to assess the possible etiological relationship. Maternal serum was studied to confirm the presence of blocking antibodies by both RRA and bioassay. Blood spots obtained from 9 infants contained potent TSH receptor-blocking activity. Samples from 2 additional babies, studied because of clinical suspicion of the disease, were also positive. Long term outcome was known in 8 of the 11 babies, and all had transient disease. Neonates with TSH receptor-blocking activity greater than 132 U/L had a significantly lower T4 level (P < 0.05) and higher TSH (P < 0.005) than those in whom TSH binding-inhibitory activity was less than 132 U/L. All 9 mothers had autoimmune thyroid disease, and 3 had more than 1 affected child. Potent blocking activity was present in 7 maternal serum samples as long as 7 yr after the births of their affected babies. We conclude that measurement of TSH binding-inhibitory activity in dried neonatal blood specimens is a simple and effective method to predict the occurrence of transient congenital hypothyroidism. The incidence of this disorder in North America is 1 in 180,000 normal infants, or approximately 2% of babies with congenital hypothyroidism.

A clinical trial with halofantrine on patients with falciparum malaria in Colombia.

A total of 120 semi-immune adult male malaria patients from an area of multidrug-resistant Plasmodium falciparum malaria were hospitalized for 42 days in Medellin, Colombia (an area of no malaria transmission), and treated with halofantrine in a double-blind, randomized, prospective clinical trial according to five different treatment schedules. Each patient was assigned to one of the following halofantrine schedules: I, one dose of 1000 mg; II, three doses of 500 mg; III, two doses of 500 mg; IV, three doses of 250 mg; and V, one dose of 750 mg. Best results (75% cure rate) were obtained with schedule II, although there was no statistically significant difference compared with the other schedules. A total of 46 patients experienced recrudescent malaria. Drug levels in plasma 72 hours after beginning treatment showed no statistically significant difference between relapsing and cured patients. Side-effects (mainly gastrointestinal) were uncommon and mild. Cardiotoxicity was studied by electrocardiogram. A mean prolongation of 28.5 ms (6.6 +/- 6.3% increase from baseline) was observed in the Q-Tc interval on day 1 of the trial.

Symptomatic non-insulin-dependent diabetes mellitus during therapy with recombinant human growth hormone.

In a 12-year-old girl, hyperglycemia and an elevated glycohemoglobin concentration developed after therapy with growth hormone for familial short stature. Both clinical and biochemical abnormalities disappeared after therapy was discontinued. The insulin response to an oral glucose tolerance test was abnormal 3 months after discontinuation of growth hormone; 18 months later, it remained delayed but was normal quantitatively.

Detection of thyrotropin binding inhibitory activity in neonatal blood spots.

Recent studies have suggested that maternal TSH receptor-blocking antibodies might be of primary etiological importance in some cases of transient congenital hypothyroidism (CH). Because these antibodies are extremely potent, we evaluated the feasibility of identifying babies at risk by using readily available newborn blood spots. Blood spots obtained from 84 normal babies (group 1) and from 354 infants whose initial T4 was less than the tenth percentile for the assay and whose TSH was 40 mU/L or more (group 2) were studied without knowledge of the diagnosis. Blood was eluted from spots overnight and evaluated for [125I]TSH binding inhibition (TBI) to solubilized porcine thyroid membranes. Four spots obtained from 3 group 2 babies, but none of those from the group 1 infants, exhibited TBI activity greater than 3 SD above the normal mean (33.9%). Four additional hypothyroxinemic infants whose mothers had Graves' disease were also negative. Subsequent follow-up revealed that all 3 positive babies had transient CH, and all 3 mothers had primary myxedema. Potent TBI activity was confirmed in the serum of all 3 mothers and in the 2 babies in whom it was evaluated at birth. We conclude that newborn blood spots can be used to detect potent maternal TBI activity, and that this identifies a baby likely to have transient, rather than permanent, CH. Because of their stability and ease of collection and handling, newborn blood spots should offer a convenient tool for future studies aimed at defining in more detail the incidence and clinical characteristics of this unique syndrome.

Taeniasis and cysticercosis.

This article focuses on clinical issues of taeniasis and cysticercosis, including a comprehensive review of the clinical data, standard and latest chemotherapy, modern concepts of pathogenesis, conventional and advanced diagnostic tests, current epidemiology, and effective means of control. Fundamental parasitology is covered to familiarize physicians and scientists with the latest concepts of parasites.

Short course albendazole treatment for neurocysticercosis in Columbia.

The efficacy of albendazole was evaluated in 20 Colombian patients with neurocysticercosis showing neurological symptoms. All had parenchymal non-enhancing cystic images by computerized tomography and a positive enzyme-linked immunosorbent assay for cysticercus antibodies in serum or cerebrospinal fluid. They stayed in hospital for 8 d during treatment with albendazole, 15 mg/kg/d in 2 divided doses, and were then followed for at least 6 months after treatment. The number of cysts was reduced by 50% after 6 months. In 7 (35%) all cysts disappeared, in 7 (35%) the number was reduced, and in the remaining 6 (30%) the number was unchanged. In the 13 patients who still had cysts at 6 months, 11 showed a moderate decrease in average cyst size and in 2 the size was unchanged. Side effects during treatment were observed in 60% of the cases, but only 3 required corticosteroids.

Prospective double-blind trial of two different doses of mefloquine plus pyrimethamine-sulfadoxine compared with pyrimethamine-sulfadoxine alone in the treatment of falciparum malaria.

This double-blind study is based on the treatment of 75 adult male patients suffering from Plasmodium falciparum malaria in Medellín, Colombia, a city in which there is no malaria transmission. The patients, who came from regions with high resistance to antimalarials, were divided into three groups receiving single-dose treatment as follows: a combination of 280 mg mefloquine, 800 mg sulfadoxine and 40 mg pyrimethamine; a combination of 420 mg mefloquine, 1200 mg sulfadoxine and 60 mg pyrimethamine; and a combination of 1500 mg sulfadoxine and 75 mg pyrimethamine. After treatment, follow-up examination was performed daily for I week and then weekly for another 3 weeks. The cure rate in the mefloquine groups (within the study period of 28 days) was 100%, and in the third group 75%. Normal blood levels of the administered drugs were found in 6 patients of the third group who were not cured; they were subsequently cured with a single dose of 1000 mg of mefloquine. Drug tolerance was good and no toxic effects were demonstrated in blood and urine examinations. While the doses in the drug combinations (containing mefloquine) gave very good results, we would recommend a slightly higher dose combination of mefloquine with sulfadoxine-pyrimethamine for the treatment of falciparum malaria in areas with a high prevalence of chloroquine resistance.

Intraocular filaria, a Loaina species, from man in Colombia.

A 4.5-mm filarial worm was removed from the anterior chamber of the left eye of a 56-year-old man who had lost the sight in the right eye due to trauma some years earlier. The worm was removed intact through an upper scleral incision with a corneal based flap. Within 2 months vision was normal. The worm was identified as a sexually mature male of an undescribed species of Loaina Eberhard and Orihel 1984, a genus related to Loa and Dirofilaria.

Two cases of human Lagochilascaris infection in Colombia.

Two human cases of infection with Lagochilascaris are described from Colombia. One patient was a 21 year-old woman who suffered from repeated attacks of tonsillitis and passage of worms from the nose. When a tonsillectomy was performed, numerous worms were found in the tissues. Treatment with thiabendazole and mebendazole was ineffective. She was cured after treatment with levamisole. The second patient was a 7 year-old girl who had a painful abscess on the neck that contained adult worms. She was also cured of this infection after treatment with levamisole. These are the first cases described from Colombia, and bring the total number of human cases recorded to twenty-three.