Multiantigen print immunoassay (MAPIA) for the diagnosis of neurocysticercosis: a single-center diagnostic optimization and accuracy study in Lima, Peru

Neurocysticercosis (NCC) is the most common helminthic infection of the human central nervous system. The antibody detection assay of choice is the enzyme-linked immunoelectrotransfer blot assay using lentil-lectin purified parasite antigens (LLGP-EITB, Western blot), an immunoassay with exceptional performance in clinical samples. However, its use is mainly restricted to a few research laboratories because the assay is labor-intensive and requires sophisticated equipment, expertise, and large amounts of parasite material for preparation of reagents. We report a new immunoprint assay (MAPIA) that overcomes most of these barriers. We initially compared the performance of five different antigen combinations in a subset of defined samples in the MAPIA format. After selecting the best-performing assay format (a combination of rGP50 + rT24H + sTs14 antigens), 148 archived serum samples were tested, including 40 from individuals with parenchymal NCC, 40 with subarachnoid NCC, and 68 healthy controls with no evidence of neurologic disease. MAPIA using three antigens (rGP50 + rT24H + sTs14) was highly sensitive and specific for detecting antibodies in NCC. It detected 39 out of 40 (97.5%) parenchymal NCC cases and 40/40 (100%) subarachnoid cases and was negative in 67 out of 68 (98.53%) negative samples. MAPIA using three recombinant and synthetic antigens is a simple and economical tool with a performance equivalent to the LLGP-EITB assay for the detection of specific antibodies to NCC. The MAPIA overcomes existing barriers to adoption of the EITG LLGP and is a candidate for worldwide use.

Synthesis of N-methylene phosphonate aziridines: reaction scope and mechanistic insights

Treatment of N-carbamoyl aziridines by the diethyl phosphite anion affords either α-methylene-phosphonate or gem-bisphosphonate derivatives containing an aziridine motif depending on the nature of the base used.

Neurocysticercosis. A frequent cause of seizures, epilepsy, and other neurological morbidity in most of the world

Neurocysticercosis is endemic in most of the world and in endemic areas it accounts for approximately 30% of cases of epilepsy. Appropriate diagnosis and management of neurocysticercosis requires understanding the diverse presentations of the disease since these will vary in regards to clinical manifestation, sensitivity of diagnostic tests, and most importantly, therapeutic approach. This review attempts to familiarize tropical neurology practitioners with the diverse types of neurocysticercosis and the more appropriate management approaches for each.

[Extramedullary intradural tuberculosis: a case report and review of the literature]

INTRODUCTION

Central nervous system tuberculosis is a common chronic infection in developing countries, being the most frequent forms: tuberculous meningitis and intracranial tuberculosis. Extramedullary intradural tuberculosis is a rare entity with few cases described in the world literature, and is usually associated with a history of tuberculous meningitis or during antituberculosis treatment.

CASE REPORT

A 17 years-old male patient, without history of tuberculosis, with subacute onset and progressive course of compressive myelopathy. Spinal magnetic resonance imaging revealed an intradural extramedullary mass lesion between the C4 and T8 spinal levels. Surgical resection of tuberculoma was realized, followed by chemotherapy. The histopathological study confirmed the diagnostic.

CONCLUSIONS

Tuberculosis of the central nervous system is an entity of high incidence in developing countries, and intradural extramedullary tuberculoma should be included in the differential diagnosis of expansive spinal cord injuries, especially if the patient is young and there is a history of pulmonary tuberculosis or tuberculous meningitis. It is also important to take it into account as part of a paradoxical reaction after the initiation of specific treatment. Although surgical resection improves compressive medullary symptoms, medical therapy remains the mainstay in the treatment of tuberculomas.

Pathogenesis of Taenia solium taeniasis and cysticercosis

Taenia solium infections (taeniasis/cysticercosis) are a major scourge to most developing countries. Neurocysticercosis, the infection of the human nervous system by the cystic larvae of this parasite, has a protean array of clinical manifestations varying from entirely asymptomatic infections to aggressive, lethal courses. The diversity of clinical manifestations reflects a series of contributing factors which include the number, size and location of the invading parasites, and particularly the inflammatory response of the host. This manuscript reviews the different presentations of T. solium infections in the human host with a focus on the mechanisms or processes responsible for their clinical expression.

High frequency of spinal involvement in patients with basal subarachnoid neurocysticercosis

OBJECTIVE

To determine the frequency of spinal neurocysticercosis (NCC) in patients with basal subarachnoid NCC compared with that in individuals with viable limited intraparenchymal NCC (≤20 live cysts in the brain).

METHODS

We performed a prospective observational case-control study of patients with NCC involving the basal cisterns or patients with only limited intraparenchymal NCC. All patients underwent MRI examinations of the brain and the entire spinal cord to assess spinal involvement.

RESULTS

Twenty-seven patients with limited intraparenchymal NCC, and 28 patients with basal subarachnoid NCC were included in the study. Spinal involvement was found in 17 patients with basal subarachnoid NCC and in only one patient with limited intraparenchymal NCC (odds ratio 40.18, 95% confidence interval 4.74-340.31; p < 0.0001). All patients had extramedullary (intradural) spinal NCC, and the lumbosacral region was the most frequently involved (89%). Patients with extensive spinal NCC more frequently had ventriculoperitoneal shunt placement (7 of 7 vs 3 of 11; p = 0.004) and tended to have a longer duration of neurologic symptoms than those with regional involvement (72 months vs 24 months; p = 0.062).

CONCLUSIONS

The spinal subarachnoid space is commonly involved in patients with basal subarachnoid NCC, compared with those with only intraparenchymal brain cysts. Spinal cord involvement probably explains serious late complications including chronic meningitis and gait disorders that were described before the introduction of antiparasitic therapy. MRI of the spine should be performed in basal subarachnoid disease to document spinal involvement, prevent complications, and monitor for recurrent disease.

High frequency of spinal involvement in patients with basal subarachnoid neurocysticercosis

OBJECTIVE

To determine the frequency of spinal neurocysticercosis (NCC) in patients with basal subarachnoid NCC compared with that in individuals with viable limited intraparenchymal NCC (≤20 live cysts in the brain).

METHODS

We performed a prospective observational case-control study of patients with NCC involving the basal cisterns or patients with only limited intraparenchymal NCC. All patients underwent MRI examinations of the brain and the entire spinal cord to assess spinal involvement.

RESULTS

Twenty-seven patients with limited intraparenchymal NCC, and 28 patients with basal subarachnoid NCC were included in the study. Spinal involvement was found in 17 patients with basal subarachnoid NCC and in only one patient with limited intraparenchymal NCC (odds ratio 40.18, 95% confidence interval 4.74-340.31; p < 0.0001). All patients had extramedullary (intradural) spinal NCC, and the lumbosacral region was the most frequently involved (89%). Patients with extensive spinal NCC more frequently had ventriculoperitoneal shunt placement (7 of 7 vs 3 of 11; p = 0.004) and tended to have a longer duration of neurologic symptoms than those with regional involvement (72 months vs 24 months; p = 0.062).

CONCLUSIONS

The spinal subarachnoid space is commonly involved in patients with basal subarachnoid NCC, compared with those with only intraparenchymal brain cysts. Spinal cord involvement probably explains serious late complications including chronic meningitis and gait disorders that were described before the introduction of antiparasitic therapy. MRI of the spine should be performed in basal subarachnoid disease to document spinal involvement, prevent complications, and monitor for recurrent disease.

Outcome prediction in monochorionic diamniotic twin pregnancies with moderately discordant amniotic fluid

OBJECTIVE

The aim of this study was to identify predictors of twin-to-twin transfusion syndrome (TTTS) and selective intrauterine growth restriction (sIUGR) in monochorionic diamniotic (MCDA) twin pregnancies with moderate amniotic fluid discordance (mAFD).

METHODS

Monochorionic twins with mAFD (n = 45; gestational age, 15-29 weeks) were assessed for extent of fluid discordance, fetal growth discordance and fetal cardiac dysfunction, and were followed longitudinally. A prediction algorithm was constructed for TTTS and sIUGR and validated in an unrelated cohort (n = 52).

RESULTS

Cardiac dysfunction could not predict TTTS or sIUGR. Twins below 20 weeks of gestation with a fluid discordance of ≥ 3.1 cm had a risk of TTTS of 85.7%. Sensitivity for TTTS was nevertheless only 55%. An intertwin weight discordance of ≥ 25% had 63% sensitivity and 76% specificity for sIUGR without TTTS.

CONCLUSION

The outcome of MCDA twins with mAFD remains unpredictable, yet high-risk and low-risk subgroups for TTTS can be identified based on severity of fluid discordance and gestational age.

Neurocysticercosis: unraveling the nature of the single cysticercal granuloma

A single enhancing lesion in the brain parenchyma, also called an inflammatory granuloma, is a frequent neurologic diagnosis. One of the commonest causes of this lesion is human neurocysticercosis, the infection by the larvae of the pork tapeworm, Taenia solium. Following the demonstration that viable cysticercosis cysts survive in good conditions for several years in the human brain, single cysticercal granulomas have been consistently interpreted as representing late degeneration of a long-established parasite. On the basis of epidemiologic, clinical, and laboratory evidence detailed in this article, we hypothesize that in most cases these inflammatory lesions correspond to parasites that die in the early steps of infection, likely as the natural result of the host immunity overcoming mild infections.

HFE gene mutations and iron status of Brazilian blood donors

Mutations of the HFE and TFR2 genes have been associated with iron overload. HFE and TFR2 mutations were assessed in blood donors, and the relationship with iron status was evaluated. Subjects (N = 542) were recruited at the Hemocentro da Santa Casa de São Paulo, São Paulo, Brazil. Iron status was not influenced by HFE mutations in women and was independent of blood donation frequency. In contrast, men carrying the HFE 282CY genotype had lower total iron-binding capacity (TIBC) than HFE 282CC genotype carriers. Men who donated blood for the first time and were carriers of the HFE 282CY genotype had higher transferrin saturation values and lower TIBC concentrations than those with the homozygous wild genotype for the HFE C282Y mutation. Moreover, in this group of blood donors, carriers of HFE 63DD plus 63HD genotypes had higher serum ferritin values than those with the homozygous wild genotype for HFE H63D mutation. Multiple linear regression analysis showed that HFE 282CY leads to a 17.21% increase (P = 0.018) and a 83.65% decrease (P = 0.007) in transferrin saturation and TIBC, respectively. In addition, serum ferritin is influenced by age (3.91%, P = 0.001) and the HFE 63HD plus DD genotype (55.84%, P = 0.021). In conclusion, the HFE 282Y and 65C alleles were rare, while the HFE 63D allele was frequent in Brazilian blood donors. The HFE C282Y and H63D mutations were associated with alterations in iron status in blood donors in a gender-dependent manner.

Primary peripheral primitive neuroectodermal tumors of the spinal cord: report of two cases and review of the literature

Primary intraspinal peripheral primitive neuroectodermal tumors (pPNETs) are extremely rare tumors with only seven reported cases in the literature. The histopathologic diagnosis of this tumor is complex and has led to a variety of treatment approaches. The distinction between central and peripheral type primary spinal cord PNETs has not always been made in the literature, leading to a paucity of data in this disease. We present here two young patients with primary intraspinal pPNET, their treatment and outcome. The first patient, a 27 year old male, presented with an intradural mass extending from L2 through L5, after multiple relapses, he is currently alive with disease after 72 months, the longest survival yet reported. The second patient, a 16 year old female, presented with an intradural mass at the cauda equina from L2 through L5, and is currently alive with responsive disease at 5 months after initial diagnosis. Here, we discuss the clinical course, the pathology and treatment for this disease and review the literature.

Effect of enteral feeding temperature on feeding tolerance in preterm infants

Thirty preterm infants were randomly assigned to one of three milk temperature groups: 37 degrees C, 24 degrees C, and 10 degrees C. Infants were fed by gavage every two hours, and gastric residuals were measured immediately prior to the next feeding. Feeding tolerance was determined by dividing the volume of gastric residual by the total volume of the feeding. Abdominal and axillary skin temperatures were monitored half-hourly. Tolerance differed significantly among the three milk temperature groups, using ANCOVA, F(2, 26) = 41.06, p < .01, accounting for 75 percent of variance shared. Post hoc Scheffe's procedure on adjusted means indicated that the infants fed the warmer milk (BT group) had significantly smaller gastric residuals (6 percent) than those fed the colder milk (RT group, 22 percent and CT group, 18 percent). No significant differences in body temperature for any of the three milk temperature groups were found. Warming milk to body temperature may promote greater feeding tolerance in the VLBW infant (< or = 1,500 gm). Results from this study provide objective data that will help nurses provide optimal nutrition to preterm infants.

[Oral premedication with clorazepate dipotassium. Comparison with oral premedication with flunitrazepam and intramuscular premedication with promethazine, pethidine and atropine in adults]

The purpose of premedication and the best form have been frequent subjects of controversy among anaesthetists in the past few years. Anxiolysis is now accepted as the main purpose. The preferred route of administration is by mouth. The intention of this study was to examine whether clorazepate dipotassium has the same sedative-hypnotic and anxiolytic effects as i.m. premedication with promethazine, pethidine and atropine.

METHODS

A total of 100 patients aged 20-65 years and due to undergo arthroscopy took part in this study. Patients in group I were given 1 mg flunitrazepam p.o. on the evening before the operation and the i.m. premedication described above. The premedication for group II consisted in clorazepate dipotassium, 50 mg on the evening before operation and 25 mg on the morning of the day of the operation. The sedative-hypnotic effects were measured on a four-point scale. The Erlangen anxiety scale (EAS) and a visual analogue scale (VAS) were used to evaluate the anxiolytic effects according to the patient's own and the observer's evaluation of mood. In addition to this, we measured amnesia, heart rate and blood pressure.

RESULTS

Clorazepate dipotassium or flunitrazepam p.o. significantly reduces anxiety 1 h after administration as measured by the EAS (P < 0.05) on the evening before the operation. This result was not, however, confirmed by the VAS for self-assessment. Patients who received premedication with clorazepate dipotassium are less anxious on the morning of the operation than patients given flunitrazepam the evening before the operation (P < 0.05); this, however, does not correspond to the VAS results. There were no differences in the other parameters compared.

DISCUSSION

Oral premedication with clorazepate dipotassium has the same sedative-hypnotic, anxiolytic and amnestic effects as i.m. premedication with promethazine, pethidine and atropine. The results of this study are better than those obtained by Tolksdorf et al., owing to the higher dosage used in our study (50 mg as against 20 mg). Tolksdorf et al. [21] failed to show any improvement on a placebo. Our results correspond to those of Drautz et al. [2] who used 50 mg of clorazepate dipotassium on the evening before and 25 mg on the morning of the day of the operation.

Transcribed and nontranscribed parts of the human ribosomal gene repeat show a similar pattern of distribution in nucleoli

The distribution pattern of the transcribed and nontranscribed parts of human ribosomal RNA genes were visualized simultaneously in the same cells by nonautoradiographic in situ hybridization. DNA probes labeled with either digoxigenin or biotin were detected in the same cells by different fluorescence systems. The signals from both the transcribed and nontranscribed parts showed a similar distribution pattern. This finding is not compatible with the conclusion, suggested by earlier studies, that the transcribed and nontranscribed parts of the rRNA genes are located at different sites within the nucleoli or in different nucleolar components.

Streptococcal pharyngitis. Comparison of latex agglutination and throat culture

Despite its imperfections, the throat culture remains the "gold standard" against which all rapid streptococcal antigen detection tests are compared. Using triple throat swabs, the accuracy of a rapid latex agglutination (LA) test and back up throat culture was determined and compared with a simultaneously obtained additional throat culture in children with suspected streptococcal pharyngitis. Although there was a 95 percent concordancy between throat cultures, the sensitivity of the throat culture was only 87 percent. Despite the LA test's lower sensitivity (78 percent), in this clinical population with a relatively low prevalence of positive throat cultures (19 percent), the predictive value of a negative LA test was only slightly lower than that of the throat culture (94-95 percent vs. 97 percent). Backup throat cultures are commonly recommended for patients with initially negative LA test results, but 10 percent of the patients with group A beta-hemolytic streptococci-positive throat cultures would have been undetected using this approach.

Induction of bilirubin-eliminating processes by methylphenobarbital in mature newborn babies

In order to find a drug for the prevention of metabolic hyperbilirubinemia of the newborn, which has less sedative effects than phenobarbital (PB) the effect of methylphenobarbital (MPB) on the plasma bilirubin concentration of newborns was studied in a double blind trial. MPB (3 x 10 mg/kg on the first day) reduced the plasma bilirubin level in mature newborns on day four by 33% in comparison to those on placebo. The results justify further investigations in premature babies, who frequently suffer from disturbances which may facilitate the development of bilirubin encephalopathy.

Stimulation of the mouse hepatic microsomal aniline p-hydroxylases by acetone and polyamines

The effects of acetone +/- spermine on the high (AH-I) and low (AH-II) affinity forms of aniline hydroxylases in the mouse hepatic microsomes were investigated under in vitro conditions. The addition of either acetone or spermine alone stimulated both AH-I and AH-II activities at low concentration while some decline in stimulation was noted at higher concentrations. In the presence of both the modifiers the observed monoxygenation rates were greater than those produced by any one enhancer alone for AH-I and more than additive for AH-II. The results suggest that the enhancement of aniline p-hydroxylation by the acetone and spermine in the mouse hepatic microsomes involves at least two separate and possibly interdependent mechanisms.