Consequences of the North American Free Trade Agreement for health services: a perspective from Mexico.

OBJECTIVES. The purposes of the study were to assess the potential impact of the North American Free Trade Agreement (NAFTA) on medical care in Mexico and to identify internal measures Mexico could take to increase the benefits and minimize the risks of free trade. METHODS. The dual nature of the health sector is examined; the Mexican, Canadian, and US health care systems are compared; and modes and consequences of international exchange of health services are analyzed. RESULTS. Four issues require immediate attention: accreditation of health care facilities, licensing and certification of professionals, technology assessment, and financial equity. CONCLUSIONS. NAFTA offers opportunities for positive developments in Mexico, provided risks can be anticipated and preventive measures can be taken to avoid negative impacts on the health system. Medical services, like other elements of the Mexican economy, must be modernized to respond to the demands of global competition. The Mexican National Academy of Medicine has recommended to the Mexican government (1) internal strengthening of the Mexican health care system to improve its ability to respond to the new conditions created by NAFTA and (2) a gradual process to facilitate equitable and mutually beneficial interactions among the three countries.     

In vitro and in vivo effects of clindamycin on polymorphonuclear leukocyte function.

The effects of clindamycin on polymorphonuclear leukocytes (PMNLs) were evaluated in vitro and in vivo in an experimental model and in immunocompromised patients with and without infection. Chemotaxis, chemiluminescence, and bactericidal capacity were evaluated using PMNLs preincubated with clindamycin in different concentrations. In the three phases of the study, clindamycin at a concentration of 2 mg/L significantly increased PMNL function. In contrast, when higher concentrations were used, PMNL function was not modified and in some cases it was decreased. Our findings suggest that clindamycin, in concentrations of 2 mg/L, positively modifies PMNL function.     

The midterm (6 years) clinical results of the Carpenter-Edwards supra-annular bioprosthesis]

We present here the clinical results with a second-generation porcine bioprosthesis, the Carpentier-Edwards supra-annular valve (CESA). Two-hundred and twenty-two CESA bioprostheses were implanted in 189 patients during a four-year period (from 1984 to 1987), either as an isolated procedure or associated to mitral or tricuspid repair. The mid-term clinical results have been evaluated after a mean follow-up of 3.4 years, being 96% complete. There were 16 in-hospital deaths (8.4%) and 6 late, potentially valve-related, cardiac deaths (1.1% patients/year). Overall, 86.7 +/- 2% of the patients were free from cardiac death at 6 years (95.1 +/- 2% of the patients surviving the operative period). Linearized rates of valve related complications were the following: 1.4% patients/year for thromboembolism (including valve thrombosis), 0.5% patients/year for treatment-related hemorrhage and 0.7% patients/year for endocarditis. We did not found any case of either intrinsic or extrinsic valve failure, unrelated to infection of thrombosis. Two patients were reoperated, one because of valve thrombosis and the other due to prosthetic valve endocarditis (reoperation rate of 0.3% patients/year). When lethal and nonlethal valve-related complications (including in-hospital deaths) were considered all together, 75.8 +/- 8.4% of the patients remained alive and free of morbid events at 6 years. When patients were grouped according to the valve replaced (aortic, mitral and multiple), best results were found with patients submitted to isolated aortic valve replacement. We conclude that the CESA bioprosthesis has an excellent mid-term clinical performance. However, longer follow-up is necessary to know if improvement in valve design and manufacturing results in increased valve durability.     

Accumulation of brown adipose tissue and nutritional status. A prospective study of 366 consecutive autopsies.

Increased amounts of brown adipose tissue have been reported to occur in association with several diseases. The objective of the present study was to determine whether brown adipose tissue accumulation is related to nutritional status. Histologic sections of periadrenal tissue prospectively obtained at consecutive autopsies from 366 adults were examined. The cases were separated into three groups: malnourished (101 autopsies), normotrophic (128 autopsies), and obese (137 autopsies), according to the Quetelet index. Of these patients, 89 had brown adipose tissue accumulation, 35 were malnourished, 32 were normotrophic, and 22 were obese. The results showed a correlation between brown adipose tissue and patient nutritional status and a higher brown adipose tissue accumulation in malnourished patients. Cardiovascular disease was the most common type of illness present in the cases with brown adipose tissue accumulation.     

Transmitter release from presynaptic terminals of electric organ: inhibition by the calcium channel antagonist omega Conus toxin

Cholinergic synaptosomes from electroplax of the ray Ommata discopyge release both ATP and ACh when depolarized with high K+ concentration in the presence of Ca2+. Others have shown that the ATP and ACh are released in the molar ratio found in isolated synaptic vesicles. Thus, it is assumed that the release of ATP reflects exocytosis of synaptic vesicles, and that transmitter release can be indirectly monitored by assaying ATP release. We present further evidence for this assumption and examine the effects of presynaptic neurotoxins on this ATP release. As expected for transmitter release, we find that depolarization-evoked ATP release is supported by Sr2+ and Ba2+ and is inhibited by the Ca channel antagonists Co2+ and Mn2+. Likewise, the presynaptic toxins omega-CmTX and omega-CgTX, omega peptides from the venom of the marine snails Conus magus and Conus geographus, respectively, inhibit 80% of the depolarization-evoked ATP release. Half-maximal inhibition of ATP release occurs with approximately 0.5 microM of either toxin. The toxins' effects are reversible, and when toxin is washed away, the time dependence of recovery of release is approximately first order and half complete within 40 min with omega-CmTX and 15 min with omega-CgTX. The Ca2+ ionophore A23187 induces Ca2+-dependent ATP release from resting synaptosomes. As would be expected of a Ca channel antagonist, omega-CmTX does not affect this ionophore-induced release. Leptinotarsin-d (LPTd), a putative Ca channel agonist from the Colorado potato beetle, evokes Ca2+-dependent ATP release from resting synaptosomes. omega-CmTX does not block LPTd-evoked release of ATP, which suggests that omega-CmTX and LPTd act at different sites.(ABSTRACT TRUNCATED AT 250 WORDS)     

Asymptomatic uveitis in young people with inflammatory bowel disease.

PURPOSE: To ascertain the prevalence of uveitis in a population of pediatric patients with inflammatory bowel disease without ocular symptoms. METHODS: We prospectively evaluated all young people who came to the pediatric gastroenterology clinic with endoscopically proven inflammatory bowel disease between March 1994 and June 1995. All the patients were examined for evidence of ocular manifestations of inflammatory bowel disease. The examination consisted of slit-lamp examination, tonometry, and indirect ophthalmoscopy. None of the patients had visual or ocular symptoms. Eighteen patients had Crohn's disease and 14 had ulcerative colitis. RESULTS: Of the 32 patients evaluated, four (12.5%) had evidence of asymptomatic ocular inflammation, defined as anterior chamber cell and flare. All patients with ocular inflammation were male. Three of these four male patients had Crohn's disease; the other had ulcerative colitis. Five patients had posterior subcapsular cataract, one had esotropia and amblyopia, and one had unilateral high myopia. CONCLUSIONS: The prevalence of asymptomatic uveitis in our population of young people with inflammatory bowel disease was 12.5%. These findings suggest the need for a screening ophthalmologic examination to rule out occult eye disease in young people with inflammatory bowel disease.     

Antinuclear antibodies in scleroderma,mixed connective tissue disease and “primary” Raynaud's phenomenon

Summary The diversity of antibodies in patients with scleroderma, mixed connective tissue disease or primary Raynaud's phenomenon could be used as a laboratory aid in the clinical diagnosis. In serum samples of 75 patients we screened for antinuclear antibodies (HEp 2 cells), anti DNA, soluble nucleoprotein and extractable nuclear antigens (Sm, rRNP, Ul-nRNP, SSA/Ro, SSB/La and Scl-70). Distinctive antinuclear antibodies pattern was identified in each group of patients. This immunologic profile is valuable for clinical diagnosis and the preferential association of certain autoantibodies with some diseases and not with others, suggest an antigen-driven stimulus for its production.