Performance of immunohistochemistry as a useful tool for the diagnosis of cutaneous leishmaniasis in Panama, Central America.

Cutaneous leishmaniasis (CL) is one of the most frequent parasitic zoonoses in Panama. Currently, conventional, molecular and histopathological tests are performed to diagnose CL. Immunohistochemistry (IHC) has proven to be a valuable tool to facilitate the diagnosis of leishmaniasis and to study the cellular immune response developed during the infection. Therefore, considering the absence of IHC in the diagnostic routine in Panama, the objective of this study is to demonstrate the usefulness of this test as a complementary diagnostic tool for improving the sensitivity of histopathology (HP) and helping to study the cellular immune response of patients. Samples from patients with suspected CL were analysed by intradermal reaction of Montenegro (IDRM), smears, culture, PCR (Viannia, Hsp-70), HP and IHC. According to the diagnostic criteria, 95.8% of patients were positive for Leishmania sp., that was characterized as Leishmania (V.) panamensis by PCR-HSP70/RFLP. From positive samples, Leishmania was detected by the tested diagnostic methods in the following degrees: 100% by IDRM, 60% by smears, 93.3% by culture, 100% by kDNA PCR, 78.3% by PCR Hsp-70, 50% by HP and 73.9% by IHC. Although IHC had a poor correlation (k = 0.191) with the diagnostic criteria, the sensitivities of both HP (76.1%) and smears (89.1%) were improved by combining them with IHC. IHC considerably improved the detection of the Leishmania parasites in the histopathological sections, supporting the need to implement this diagnostic tool in Panama. In addition, immunohistochemistry allows evaluation of the patient's immune response and thus provides new guidelines for the treatment and control of CL in Panama.

Evaluation of PCR for cutaneous leishmaniasis diagnosis and species identification using filter paper samples in Panama, Central America.

Cutaneous leishmaniasis (CL) is a major vectorborne disease in Panama. In this study, the diagnostic performance and usefulness of two DNA extraction procedures from skin scraping samples collected on FTA filter paper for subsequent PCR diagnosis of CL was evaluated. A positive CL laboratory diagnosis was based on a positive parasitological test (Giemsa-stained smears or in vitro culture) and/or positive PCR test performed from skin scrapings collected in TE buffer (PCR-TE). Of 100 patients with skin lesions suggestive of CL, 82 (82%) were confirmed as CL positive. The sensitivity was calculated for each of the PCR approaches from samples collected on filter paper. The highest sensitivity was achieved by PCR-FTA processed by Chelex 100 (PCR-Chelex) (0.94). PCR-FTA extracted using the FTA purification reagent presented a lower sensitivity (0.60). Good concordance between routine PCR-TE and PCR-Chelex was observed (percent agreement=0.88, κ index=0.65). In conclusion, use of FTA filter paper for skin scraping collection combined with PCR is a reliable and convenient method for CL diagnosis in Panama, with comparable performance to the routine PCR method and with improved sensitivity compared with those of conventional parasitological methods.

Temporal variation in the pollen:ovule ratios of Clarkia (Onagraceae) taxa with contrasting mating systems: field populations.

Among plants, pairs of selfing vs. outcrossing sister taxa provide interesting systems in which to test predictions concerning the magnitude and direction of temporal changes in sex allocation. Although resource availability typically declines towards the end of the growing season for annual taxa, temporal changes in mating opportunities depend on mating system and should change less in selfing taxa. Consequently, given that the pollen:ovule (P:O) ratio of flowers reflects the investment in (and potential fitness pay-off due to) male vs. female function, we predicted that the P:O ratio should also be less variable among and within selfers than in closely related outcrossers. To test these predictions, we measured temporal changes in sex allocation in multiple field populations of two pairs of sister taxa in the annual flowering plant genus Clarkia (Onagraceae). In the outcrossing Clarkia unguiculata and the selfing Clarkia exilis, ovule production declined similarly from early to late buds, whereas pollen production remained constant or increased in the outcrosser but remained constant or decreased in the selfer. Consequently, the P:O ratio increased within unguiculata populations but marginally increased or stayed constant in exilis populations. In all populations of the selfing Clarkia xantiana spp. parviflora and the outcrossing C. x. spp. xantiana, both ovule and pollen production per flower declined over time. The effects of these declines on the P:O ratio, however, differed between subspecies. In each xantiana population, the mean P:O ratio did not differ between early and late flowers, although individuals varied greatly in the direction and magnitude of phenotypic change. By contrast, parviflora populations differed in the mean direction of temporal change in the P:O ratio. We found little evidence to support our initial predictions that the P:O ratio of the selfing taxa will consistently vary less than in outcrossing taxa.

Modelos fisiopatológicos de la esquizofrenia; de dopamina a glutamato, de glutamato a GABA / Pathophysiologycal models of schizophrenia; from dopamine to glutamate, and glutamate to GABA

A pesar de los avances en el conocimiento de las bases biológicas de la conducta, los mecanismos neurobiológicos precisos involucrados en la esquizofrenia permanecen desconocidos. Como consecuencia de esto las terapias farmacológicas actuales descansan más sobre bases empíricas que sobre explicaciones fisiopatológicas. En el presente trabajo se propone un modelo de la esquizofrenia que podría ser de utilidad en el diseño de nuevas estrategias terapéuticas. Este modelo intenta integrar recientes hallazgos neuropsicológicos y de neuroimagen con lo que hoy sabemos respecto a la biología del desarrollo y plasticidad cerebral normal. Se propone que la esquizofrenia es una enfermedad del neurodesarrollo caracterizada por una neurotransmisión glutamatérgica inadecuadamente modulada a consecuencia de la disfunción de interneuronas GABAérgicas en múltiples regiones del cerebro. Anormalidades sutiles en el balance entre GABA y Glutamato explicarían los defectos en la cognición, la conducta social y la coordinación motora reportados en las etapas pre-psicóticas de la esquizofrenia. Más tarde en la historia natural de la enfermedad, estados hiperglutamatérgicos desencadenados por la incrementada neurotransmisión dopaminérgica propia de la peri-adolescencia y adultez temprana llevarían a la psicosis. Esta excesiva actividad glutamatérgica conduciría a su vez a las reducciones progresivas en sustancia gris y blanca observadas en recientes estudios prospectivos. En apoyo a esta hipótesis, se describen estudios propios y de otros laboratorios con pacientes esquizofrénicos, así como en un modelo animal de exposición intermitente a fenciclidina. Como corolario, drogas moduladoras de la neurotransmisión glutamatérgica, tales como acamprosato y lamotrigina, son propuestas como estrategias terapéuticas potencialmente utilizables en las etapas tempranas de la esquizofrenia.

Real-time polymerase chain reaction diagnosis of leishmaniasis in Panama from both fresh and frozen tissue.

Skin biopsies stored in ethanol from 49 patients with suspected cutaneous leishmaniasis (CL) were tested in a real-time polymerase chain reaction (PCR) assay and compared with conventional diagnostic methods. With clinical diagnosis as the gold standard, PCR had a sensitivity of 96% (47/49) vs. 61% (30/49) for histopathology and 33% (16/49) for culture. In addition, DNA was extracted from 70 frozen smears of lesions from suspected cases of CL and tested with the same assay. In these samples, the PCR had a sensitivity of 61% (43/70) vs. 56% (39/70) for histopathology and 41% (29/70) for culture. In this study, real-time PCR offered a rapid diagnosis with an enhanced sensitivity over conventional methods. Although the yield of PCR diagnosis was lower when testing frozen smears, the assay still outperformed existing diagnostic modalities.

Review of respiratory care of the patient with amyotrophic lateral sclerosis.

Respiratory failure is the leading cause of death in patients with amyotrophic lateral sclerosis (ALS). We review the physiology of respiratory compromise in ALS and techniques of monitoring respiratory function. Treatment options, including pharmacologic interventions, aspiration precautions, and invasive and noninvasive modes of mechanical ventilation are reviewed. Our clinical experience with respiratory failure in ALS demonstrates significantly prolonged survival in subjects who elect to receive noninvasive mechanical ventilation (19.25 vs. 80.4 days, p < 0.01). Four of 18 patients who elected to receive noninvasive ventilation decided to discontinue treatment. Four of 13 patients who were receiving mechanical ventilation elected to discontinue life support. The decision to utilize these modalities must be made with realistic considerations of the patient's quality of life.

Primary repair of the cholecyst-enteric fistula in gallstone ileus.

Gallstone ileus is a rare cause of mechanical bowel obstruction. The attendant lack of awareness by the clinician will not only result in the diagnosis being made intraoperatively but will also affect the adequacy of the preoperative preparation of these ill patients. These patients are often elderly, septic and have significant concomitant medical illnesses. Recently two patients with gallstones ileus were managed with enterolithotomy and primary repair of the cholecyst-duodenal fistula at the University Hospital of the West Indies, Jamaica. Their clinical presentations and progress are described along with a review of the classical clinical course, radiological features, and operative choices available.

Biliary surgery in patients with sickle-cell anaemia.

The results of biliary surgery are reported in 12 consecutive patients with homozygous sickle-cell (SS) disease treated over a two-year period at the University Hospital of the West Indies, Kingston, Jamaica. Recommendations for the surgical management of these patients are outlined.

Counseling the Hispanic male adolescent.

A rationale is given for providing counseling to Hispanic male adolescents. Characteristics of this population are discussed and specific techniques for counseling are suggested.

Efficacy of ketoconazole against Leishmania braziliensis panamensis cutaneous leishmaniasis.

PURPOSE, PATIENTS, AND METHODS: The classic agent for cutaneous leishmaniasis is pentavalent antimony. However, there are no reports of the efficacy of antimony versus placebo or of the efficacy of any alternative therapy versus either antimony or placebo. In the present report, the oral antifungal agent ketoconazole (600 mg/day for 28 days) was compared to a recommended regimen of intramuscular Pentostam (20 mg antimony/kg, with a maximum of 850 mg antimony/day, for 20 days) in a randomized study of the treatment of Panamanian cutaneous leishmaniasis due to Leishmania braziliensis panamensis. A separate group of patients with this disease was administered placebo. RESULTS: Ketoconazole clinically cured 16 of 21 (76%) patients. The lesions on nine patients healed by 1 month after therapy, and the lesions healed by 3 months after therapy on the other seven patients. Side effects were limited to a 27% incidence of mild, reversible hepatocellular enzyme elevation and an asymptomatic, reversible, approximately 70% decrease in serum testosterone in all patients. Pentostam cured 13 of 19 (68%) patients; the lesions on seven patients healed by the end of therapy, and the lesions on four other patients healed by 1 month after the end of therapy. Side effects were a 47% incidence of mild, reversible hepatocellular enzyme elevation and the morbidity due to 20 intramuscular injections in almost all patients. The placebo group of 11 patients had a 0% cure rate. By 1 month after therapy, all placebo-treated patients demonstrated new lesions or one lesion that was 23% to 875% larger than before therapy. CONCLUSION: Both ketoconazole and Pentostam were more effective than placebo against L. braziliensis panamensis cutaneous leishmaniasis. Oral ketoconazole is comparable in efficacy to this parenteral Pentostam regimen and can be recommended as initial treatment for this disease.

Treatment of American cutaneous leishmaniasis with orally administered allopurinol riboside.

Eighteen patients received 1,250 mg of allopurinol riboside (AR) four times daily for 28 d. Nine of the patients concurrently received 500 mg probenecid (PB) four times daily. Cure was assessed clinically and parasitologically. Patients who had culture-positive and nonhealing lesions 3 mo after therapy received pentavalent antimony. Of the nine patients who received AR alone, four (44%) had clinical improvement at the end of therapy and two (22%) were culture-negative. A third patient became culture negative at 2 mo after therapy. The culture-negative patients were completely healed at 1 mo and remained so at 1 y after therapy. Of the nine patients who received AR plus PB, four had complete healing and two had clinical improvement at the end of therapy; however, all patients remained culture-positive. At 2-3 mo after therapy, six (67%) of the patients were completely healed, and of these, five (56%) were culture-negative. The drug was well-tolerated.

[Mucocutaneous leishmaniasis in Panama. Etiologic agent, epidemiologic and clinical aspects]. / Leishmaniasis mucocutánea en Panamá. Agente etiológico, aspectos epidemiológicos y clínicos.

From November 1985 to December 1988, 33 patients were enrolled at Santo Tomas Hospital and Gorgas Memorial Laboratory to study the etiology, epidemiology and clinical characteristics of mucocutaneous leishmaniasis. Seventeen were males and 16 females, 14 to 80 years old from the endemic rural areas of the provinces of Panama, Colón, Coclé, Darién, Veraguas, Bocas del Toro and San Blas. In 8 patients the respiratory mucosa involvement occurred at the time of the primary infection and 25 had the involvement after an incubation period of 2 to 30 years. Twenty one of these 25 patients had a clear history of cutaneous leishmaniasis and the characteristic depressed and hyperpigmented scar of a previous leishmanial infection. The Montenegro skin test was positive in all the patients, serology in 84%, direct smear in 47%, histopathology in 37% and culture in 26%. The strains were characterized as L. braziliensis panamensis by electrophoresis of isoenzymes. Possible risk factors in development of MCL were found to be female sex and the lack of past treatment of CL. The mucosal involvement was mild in the majority of the patients, the infection was localized in the nasal mucosal (nasal septum and inferior turbinate) in 91% of the patients, and the most common symptoms were epistaxis, nasal obstruction and rhinorrhea.