Multifocal primary extranodal B-cell non-Hodgkin's lymphoma involving six extranodal sites

An unusual case of Epstein-Barr virus-negative primary extranodal B-cell non-Hodgkin's lymphoma involving six anatomical sites is described in a report that challenges the role of organotropism in the pathogenesis of extranodal lymphoma.

Excitatory action of hypocretin/orexin on neurons of the central medial amygdala

The neurons of the lateral hypothalamus that contain hypocretin/orexin (hcrt/orx) are thought to promote arousal through the excitatory action they exert on the multiple areas to which they project within the CNS. We show here that the hcrt/orx peptides can also exert a strong action on the amygdala, a structure known for its implication in emotional aspects of behavior. Indeed, the hcrt/orx peptides, applied in acute rat brain slices, excite a specific class of "low threshold burst" neurons in the central medial (CeM) nucleus which is considered as a major output of the amygdala. These excitatory effects are postsynaptic, mediated by Hcrt2/OX2 receptors and result from the closure of a potassium conductance. They occur on a class of neurons that are also excited by vasopressin acting through V1a receptors. These results suggest that the hcrt/orx system can act through the amygdala to augment arousal and evoke the autonomic and behavioral responses associated with fear, stress or emotion.

Molecular markers and their prognostic impact in patients with advanced prostate cancer undergoing intermittent androgen suppression

OBJECTIVE

Tumour features were evaluated during intermittent androgen suppression (IAS), and their prognostic impact on the first off-treatment time was analysed.

PATIENTS AND METHODS

Twenty patients with advanced prostate cancer underwent three consecutive prostate biopsies during the first cycle, namely at the beginning of androgen deprivation, 8 months after continuous therapy and at the time of prostate-specific antigen (PSA) progression above 20 ng/ml. Biopsy specimens were immunohistochemically processed and analysed for the apoptotic index (AI), Ki-67, p53 and Bcl-2 to investigate eventual changes over time. Correlations and regression analysis were performed to assess the prognostic significance of clinical and pathological parameters in predicting the first off-treatment time.

RESULTS

In contrast to the AI, p53 and Bcl-2, Ki-67 was the only marker that significantly changed over time (P=0.008). The first off-treatment time correlated significantly with pretreatment PSA (r=-0.594; P<0.01), testosterone recovery time (r=0.590; P=0.013) and biopsy grade (r=-0.738; P<0.01); only the latter gaining an independent factor in the multivariate analysis (P=0.022).

CONCLUSIONS

During IAS, Ki-67 was the only molecular marker that consistently changed over time. However, it did not correlate with off-treatment time that was predicted independently by the initial biopsy grade only. First off-treatment time was best predicted by clinical parameters and molecular markers from needle biopsies did not further contribute to a better patient selection.

Opposite effects of noradrenaline and acetylcholine upon hypocretin/orexin versus melanin concentrating hormone neurons in rat hypothalamic slices

Hypocretin/orexin (Hcrt/Orx) and melanin concentrating hormone (MCH) are peptides contained in overlapping cell groups of the lateral hypothalamus and commonly involved in regulating sleep-wake states and energy balance, though likely in different ways. To see if these neurons are similarly or differentially modulated by neurotransmitters of the major brainstem arousal systems, the effects of noradrenaline (NA) and carbachol, a cholinergic agonist, were examined on identified Hcrt/Orx and MCH neurons in rat hypothalamic slices. Whereas both agonists depolarized and excited Hcrt/Orx neurons, they both hyperpolarized MCH neurons by direct postsynaptic actions. According to the activity profiles of the noradrenergic locus coeruleus and cholinergic pontomesencephalic neurons across the sleep-waking cycle, the Hcrt/Orx neurons would be excited by NA and acetylcholine (ACh) and thus active during arousal, whereas the MCH neurons would be inhibited by NA and ACh and thus inactive during arousal while disinhibited and possibly active during slow wave sleep. According to the present pharmacological results, Hcrt/Orx neurons may thus stimulate arousal in tandem with other arousal systems, whereas MCH neurons may function in opposition with other arousal systems and thus potentially dampen arousal to promote sleep.

Orexins/hypocretins excite basal forebrain cholinergic neurones

The orexins (orexin A and B, also known as hypocretin 1 and 2) are two recently identified neuropeptides (de Lecea et al., 1998; Sakurai et al., 1998) which are importantly implicated in the control of wakefulness (for reviews see Hungs and Mignot, 2001; van den Pol, 2000; Willie et al., 2001 ). Indeed, alteration in these peptides' precursor, their receptors or the hypothalamic neurones that produce them leads to the sleep disorder narcolepsy (Chemelli et al., 1999; Lin et al., 1999; Peyron et al., 2000; Thannickal et al., 2000). The mechanisms by which the orexins modulate wakefulness, however, are still unclear. Their presence in fibres coursing from the hypothalamus (Peyron et al., 1998) up to the preoptic area (POA) and basal forebrain (BF) suggests that they might influence the important sleep and waking neural systems situated there (Jones, 2000). The present study, performed in rat brain slices, demonstrates, however, that the orexins have no effect on the GABA sleep-promoting neurones of the POA, whereas they have a strong and direct excitatory effect on the cholinergic neurones of the contiguous BF. In addition, by comparing the effects of orexin A and B we demonstrate here that orexins' action depends upon orexin type 2 receptors (OX(2)), which are those lacking in narcoleptic dogs (Lin et al., 1999). These results suggest that the orexins excite cholinergic neurones that release acetylcholine in the cerebral cortex and thereby contribute to the cortical activation associated with wakefulness.

Orexins (hypocretins) directly excite tuberomammillary neurons

Wakefulness has recently been shown to depend upon the newly identified orexin (or hypocretin) neuropeptides by the findings that alteration in their precursor protein, their receptors or the neurons that produce them leads to the sleep disorder narcolepsy in both animals and humans. The questions of how and where these brain peptides act to maintain wakefulness remain unresolved. The purpose of the present study was to determine whether the orexins could directly affect hypothalamic histaminergic neurons, which are known to contribute to the state of wakefulness by their diffuse projections through the brain. Using brain slices, we recorded in the ventral tuberomammillary nuclei from neurons identified as histaminergic on the basis of their previously described morphological and electrophysiological characteristics and found that they were depolarized and excited by the orexins through a direct postsynaptic action. We then compared the depolarizing effect of orexin A and B and found that they were equally effective upon these cells. This latter finding suggests that the effect of orexins is mediated by orexin type 2 receptors, which are those lacking in narcoleptic dogs. Our results therefore show that the histaminergic neurons of the tuberomammillary nuclei represent an important target for the orexin system in the maintenance of wakefulness.

Depletion of taurine in experimental diabetic neuropathy: implications for nerve metabolic, vascular, and functional deficits

In diabetes, increased oxidative stress, disruption of signal transduction pathways, and endothelial dysfunction have been critically implicated in the pathogenesis of experimental diabetic neuropathy (EDN). The development of nerve conduction slowing in diabetes is accompanied by depletion of the beta-amino acid taurine. Since taurine functions as an antioxidant, calcium modulator, and vasodilator, taurine depletion may provide a pathogenetic link between nerve metabolic, vascular, and functional deficits complicating diabetes. The mechanism(s) of nerve taurine depletion, the localization of critical taurine deficits, and its pathophysiological significance in EDN are however unknown. This study explored the pathophysiological effects of selective nerve taurine replacement in streptozotocin-diabetic (STZ-D) rats. A polyclonal human taurine transporter (TT) antibody was also generated in order to determine potential loci of critical taurine depletion. Two weeks of STZ-D reduced sciatic motor nerve conduction velocity (NCV) by 23% (P < 0.01), decreased composite nerve blood flow by 38% (P < 0.01), and reduced nerve taurine content by 29% (P < 0.05). In STZ-D rats, a 1% taurine diet corrected nerve taurine depletion, prevented motor NCV slowing, and partially attenuated composite nerve blood flow deficits. After 6 weeks of STZ-D, a 1% taurine diet ameliorated motor NCV slowing and endoneurial nutritive blood flow deficits, prevented digital sensory NCV slowing, and reduced ouabain-sensitive nerve (Na,K)-ATPase activity. Immunohistochemical studies localized taurine and the TT to the vascular endothelium and Schwann cells of the sciatic nerve. In conclusion, taurine depletion in the vascular endothelium and Schwann cells of the sciatic nerve may contribute to the neurovascular and metabolic deficits in EDN.

Successful treatment of metastatic retinoblastoma

BACKGROUND

In the past, patients with metastatic retinoblastoma have had a poor prognosis when treated with conventional modalities. In the current study, the authors evaluated the use of combined intensive conventional chemotherapy, high dose chemotherapy with autologous stem cell rescue (ASCR), and radiation therapy.

METHODS

Four patients with metastatic retinoblastoma were treated. All had orbital and bone marrow metastases. In addition, three patients had bone metastases and two patients had liver metastases. None had central nervous system disease. Patients received intensive conventional chemotherapy that included vincristine, cyclophosphamide, etoposide, and either cisplatin or carboplatin. Stem cells were harvested after bone marrow disease was no longer detectable. High dose chemotherapy with carboplatin (500 mg/m(2)/day x 3 days or area under the curve = 7 via the Calvert formula) and thiotepa (300 mg/m(2)/day x 3 days) with (n = 3 patients) or without (n = 1 patient) etoposide (250 mg/m(2)/day x 3 days) was administered with ASCR. Sites that originally harbored bulky disease were irradiated after recovery from the high dose chemotherapy.

RESULTS

The therapy was associated with substantial acute hematopoietic and mucosal toxicities. At last follow-up, all four patients had survived event free from 46-80 months after the diagnosis of metastatic disease.

CONCLUSIONS

The treatment strategy described in the current study is effective for patients with metastatic retinoblastoma that does not involve the central nervous system. However, a multicenter trial should be considered to evaluate it in a larger group of patients.

[C-reactive protein, Il-6 and procalcitonin as infection parameters in children with oncologic diseases]

BACKGROUND

Due to anti-neoplastic therapy, there is a high incidence of infections and fever in pediatric patients with malignant disease. We have searched for parameters that may be of value in the early diagnosis of infection, in discriminating between bacterial and non-bacterial causes and for monitoring the response to antimicrobiotic therapy.

PATIENTS

46 febrile episodes in 33 children with malignant diseases under anti-neoplastic therapy, aged 0.5 to 17 years, were included. Each patient was supplied with a central venous catheter (Hickman catheter).

METHODS

Blood was taken for the evaluation of C-reactive-protein (CRP), Interleukin-6 (IL-6) and Procalcitonin (PCT). Laboratory data included WBC, blood cultures, as well as microbiologic and serologic tests for important infectious agents. Patients were grouped as follows: 1. Patients with febrile diseases and positive blood cultures, 2. Patients with localized bacterial or mycotic infections and negative blood cultures, 3. Patients with fever of unknown origin, 4. Patients with viral infections, 5. Control group.

RESULTS

CRP and IL-6 were more sensitive than PCT in detecting bacterial and mycotic diseases in leukopenic children, because of low PCT-levels in patients with localized infections. IL-6 values were high shortly after onset of fever and decreased under sufficient antimicrobiotic therapy until day three.

CONCLUSIONS

Because of the quick response, IL-6 may be helpful in monitoring antimicrobiotic therapy. Using Procalcitonin-levels, we were not able to distinguish between localized bacterial and viral infection in leukocytopenic patients.

Mycophenolic acid area under the curve values in African American and Caucasian renal transplant patients are comparable

The possibility of an effect of ethnicity on the pharmacokinetics of mycophenolic acid, the immunosuppressive metabolite of the prodrug mycophenolate mofetil, was studied over 90 days following renal transplantation in African American (n = 13) and Caucasian patients (n = 20). Since renal dysfunction and time after transplant surgery are two factors known to alter mycophenolic acid pharmacokinetics, two-way analysis of variance of the data at each time point with ethnicity and renal function status as covariates was used to evaluate the possibility of an ethnicity effect on the pharmacokinetic parameters. No statistically significant difference based on ethnicity was detected for the primary pharmacokinetic parameters, abbreviated mycophenolic acid area under the concentration-time curve (MPA AUC), or the predose trough concentration on study days 4, 7, 14, 28, or 90. A statistically significant decrease in MPA AUC and increase in oral apparent clearance were observed in renally impaired patients regardless of ethnicity on days 4, and 4 and 7, respectively. The suggested mechanism for these differences is uremia-induced increased MPA free fraction, leading to a temporary increased clearance for this restrictively cleared drug.

Mycophenolic acid area under the curve values in African American and Caucasian renal transplant patients are comparable

The possibility of an effect of ethnicity on the pharmacokinetics of mycophenolic acid, the immunosuppressive metabolite of the prodrug mycophenolate mofetil, was studied over 90 days following renal transplantation in African American (n = 13) and Caucasian patients (n = 20). Since renal dysfunction and time after transplant surgery are two factors known to alter mycophenolic acid pharmacokinetics, two-way analysis of variance of the data at each time point with ethnicity and renal function status as covariates was used to evaluate the possibility of an ethnicity effect on the pharmacokinetic parameters. No statistically significant difference based on ethnicity was detected for the primary pharmacokinetic parameters, abbreviated mycophenolic acid area under the concentration-time curve (MPA AUC), or the predose trough concentration on study days 4, 7, 14, 28, or 90. A statistically significant decrease in MPA AUC and increase in oral apparent clearance were observed in renally impaired patients regardless of ethnicity on days 4, and 4 and 7, respectively. The suggested mechanism for these differences is uremia-induced increased MPA free fraction, leading to a temporary increased clearance for this restrictively cleared drug.

Parvoviral infection associated with increased nuchal translucency: a case report

An increased fetal nuchal translucency detected by first trimester ultrasound has been associated with an elevated risk of aneuploidy. The etiology of the increased nuchal translucency in fetuses with normal chromosomes is uncertain, but it has been associated with poor pregnancy outcome. We report a fetus with increased nuchal translucency and a normal karyotype, in which parvovirus was detected by polymerase chain reaction in the amniotic fluid. Although an ultrasound detected an increased nuchal fold thickness in the second trimester, the pregnancy was otherwise uncomplicated. Parvovirus should be considered as a possible etiology of increased nuchal translucency. The risks to a fetus with first trimester parvovirus infections diagnosed under these conditions are uncertain and require larger studies.

Alteration of the expression of the hypocretin (orexin) gene by 2-deoxyglucose in the rat lateral hypothalamic area

Following an i.p. injection of 2-deoxyglucose (2DG), a nonmetabolizable analogue of glucose known to induce intracellular glucopenia, a progressive decrease in the level of hypocretin (Hcrt)/orexin mRNA was observed in the rat lateral hypothalamus while the melanin-concentrating hormone (MCH) expression in neighbouring neurons remained unaffected. This result together with the previously reported stimulation of Hcrt expression by insulin confirms that Hcrt neurons, but not MCH neurons, are sensitive to glucose availability and suggests that they respond through different mechanisms and/or different pathways to intracellular glucopenia and hypoglycemic conditions.

No major effect of estrogen receptor gene polymorphisms on bone mineral density or bone loss in postmenopausal Danish women

The polymorphisms of the estrogen receptor (ER) gene defined by the restriction enodonucleases PvuII and XbaI have recently been reported to be associated with bone mineral density (BMD) in postmenopausal women. To investigate the possible relation of the PvuII and XbaI restriction fragment-length polymorphisms of the ER gene with BMD in Danish postmenopausal women, two studies were undertaken: 1) a cross-sectional study of 499 postmenopausal women, where the ER genotypes and alleles were related to BMD of the hip, spine, and lower forearm; and 2) a longitudinal study of 101 postmenopausal women followed up for 18 years. In the latter study, late postmenopausal bone loss in the hip and spine was determined over a period of 6 years in women (mean age of 63 to 69 years), and long-term postmenopausal bone loss in the lower forearm was determined over a period of 18 years in women (mean age of 51 to 69 years). Genotyping was performed through the restriction cleavage of polymerase chain reaction-amplified genomic DNA with the two restriction enzymes, PvuII and XbaI. Restriction fragment-length polymorphisms were represented as P or p (PvuII) and X or x (XbaI), with the lower case letters signifying the presence of the restriction site. The frequencies of the ER genotypes were similar to previously published genotype frequencies in Caucasian and Asian populations. No significant effect of the ER genotypes or alleles on BMD was found at any site, nor was there a relation between ER genotypes and the rate of bone loss either in the hip and spine over 6 years, or in the lower forearm over 18 years. In conclusion, we could not demonstrate any major effect of the ER gene polymorphisms on BMD or rate of bone loss in healthy postmenopausal Danish women.

The influence of gender and emotional versus instrumental support on cardiovascular reactivity in African-American adolescents

Research suggests that females seek out, prefer, and are more receptive to emotional support (encouragement), and that males seek out, prefer, and are more receptive to instrumental support (problem-solving). Thus, we hypothesized that boys would show lower blood pressure (BP) reactivity in response to instrumental than emotional or no support, and that girls would show lower BP reactivity in response to emotional than instrumental or no support. Forty-eight healthy African-American adolescents (50% males) participated in a role play conflict task and were randomized to receive either emotional, instrumental, or no support (presence only) from a confederate. Boys showed lower systolic blood pressure (SBP) reactivity in the instrumental than in the emotional or no support conditions and lower recovery SBP as compared to boys in the emotional or no support conditions. A similar pattern of results was demonstrated for diastolic blood pressure (DBP) reactivity. Girls, however, did not demonstrate lower BP reactivity in response to emotional as compared to instrumental support. These findings suggest that instrumental and emotional support differentially influence cardiovascular (CV) reactivity in African-American boys versus girls.

The prevalence of salt sensitivity in an African-American adolescent population

This study examined the prevalence of salt-sensitivity (SS) in 140 healthy African-American adolescents. SS was defined as an increase in mean blood pressure > or =5 mm Hg from a 5-day low salt (Na+) diet (50 mmol/24 hr) to a 10-day high Na+ diet (150 mmol/24 hr NaCl supplement); remaining subjects were classified as salt-resistant (SR). Dietary compliance was defined as Na+ excretion < or =50 mmol/24 hr for the low Na+ diet and > or =165 mmol/24 hr for the high NaCl supplement diet. 31 (22%) subjects were classified as SS and 109 (78%) as SR. There were no significant differences between SS and SR subjects on baseline characteristics, family history of hypertension, or on resting blood pressure or heart rate measures. As expected, SS subjects showed a greater increase in mean, systolic, and diastolic blood pressures (P<.001 for all) than SR subjects in response to the high NaCl supplement. There was a greater increase in weight (P<.01) and Quetelet Index (P<.05) for SS than SR subjects in response to Na+ loading. These results are the first to show that SS is prevalent in a subgroup of healthy African-American adolescents.

Rat diencephalic neurons producing melanin-concentrating hormone are influenced by ascending cholinergic projections

Innervation of diencephalic neurons producing melanin-concentrating hormone by choline acetyltransferase-containing axons was examined using double immunohistochemistry. In the rostromedial zona incerta and perifornical regions of the lateral hypothalamic area, many choline acetyltransferase-positive fibers were detected in the immediate vicinity of melanin-concentrating hormone perikarya and their proximal dendrites. Putative contact sites were less abundant in the far lateral hypothalamus, and only scattered close to the third ventricle. After injections of the retrograde tracer FluoroGold, most of these projections appeared to originate in the pedunculopontine and laterodorsal tegmental nuclei. Finally, to determine the putative effect of acetylcholine on the melanin-concentrating hormone neuron population, the cholinergic agonist carbachol was added to the medium of hypothalamic slices in culture. Using competitive reverse transcriptase-polymerase chain reaction, carbachol was found to induce a rapid increase in the melanin-concentrating hormone messenger RNA expression. This response was abolished by both atropine, a muscarinic antagonist, and hexamethonium, a nicotinic antagonist. Thus, the bulk of these results indicates that the diencephalic melanin-concentrating hormone neurons are targeted by activating ascending cholinergic projections.

Survival of rat MCH (melanin-concentrating hormone) neurons in hypothalamus slice culture: histological, pharmacological and molecular studies

Hypothalamic slices containing the lateral hypothalamic area (LHA) were prepared from 6- to 8-day-old rats and maintained in stationary culture for up to 35 days in order to analyse how well the melanin-concentrating hormone (MCH) neurons survived. As previously reported for other brain areas, this method yielded a long-term well-preserved organotypic organization. Light- and electron-microscopic investigations showed that differentiation continued and that synaptic contacts developed in vitro. After a period of elimination of damaged cells and fibres, most of the remaining neurons and glial cells retained a normal morphology throughout the culture period. MCH neurons, in particular, survived well as attested by the strong immunocytochemical and in situ hybridization signals still observed after several weeks. In a comparison with the day of explantation, competitive reverse transcription/polymerase chain reaction demonstrated the remarkable stability of the level of MCH mRNA at least until the 20th day in culture; after 30 days, the clear decrease in this level seemed to be correlated with a loss of MCH neurons, rather than with a decrease in MCH expression. After 10 days of culture, the incubation of slices in the presence of the hormone leptin (50 ng/ml) resulted in a strong decrease of MCH gene expression, suggesting that MCH neurons retained their physiological properties. Thus, the LHA slice stationary culture, especially between one and three weeks (i.e. after tissue stabilization and before extensive cell loss), appears to be a suitable method for physiological and pharmacological studies of these neurons.

Melanin-concentrating hormone expression in slice cultures of rat hypothalamus is not affected by 2-deoxyglucose

In rats, melanin-concentrating hormone (MCH) neurons are mainly located within the lateral hypothalamic area (LHA). This area is known to be involved in the control of feeding and to contain glucose-sensitive cells. As a role for MCH in the regulation of food intake has been reported, we investigated the effects of 2-deoxyglucose (2DG) on MCH expression in cultured LHA slices, to verify if MCH neurons are sensitive to local glucoprivation through a modulation of MCH synthesis. After a 2-10 h 2DG incubation, competitive reverse transcription-polymerase chain reaction (RT-PCR) did not show any variation of MCH mRNA; no change was also observed in MCH immunocytochemical labeling. A slight decrease of MCH mRNA (5-15%) after a 17 h 2DG treatment might be due to a general degradation of neurons induced by long-term glucoprivation. In conclusion, we suggest that MCH neurons are not the glucose-sensitive cells previously described in the LHA and that the signals inducing their previously reported response to glycemia variations do not arise from the LHA itself.

Conversion from Sandimmune to Neoral in organ transplant recipients

The pharmacokinetic profiles of Sandimmune and Neoral vary considerably among transplant recipients. Cyclosporine exposure is far more consistent with Neoral than it is with Sandimmune. Because intrapatient variability of drug exposure has been demonstrated to be a risk factor for chronic rejection, this difference becomes important. Neoral also has a linear dose response and a stronger correlation between trough level and drug exposure. Dose linearity greatly facilitates accurate dose titration. Results of controlled studies in which kidney, liver, and heart transplant recipients were converted from Sandimmune to Neoral have shown that conversion on a 1:1 mg basis results in more predictable bioavailability and often in reductions in cyclosporine dose. Carefully monitored conversion has not been associated with increased side effects, and any side effects that do emerge can usually be managed by taking Neoral with food, changing the dose from every 12 hours to every 8 hours, or through dose reduction.

Efficacy of succimer chelation for reducing brain Pb levels in a rodent model

Increasing evidence indicates that early low-level lead (Pb) exposure produces enduring cognitive impairment in children, underscoring the need to develop improved therapeutic intervention. Although chelating agents have been shown to effectively reduce body Pb levels, it is not yet known whether this treatment ameliorates Pb-induced cognitive dysfunction. Clinical research in this area is hampered by the need to rely on reductions in blood Pb levels as the index of treatment efficacy, despite the fact that brain Pb level is the exposure parameter of greatest relevance to neurocognitive outcomes. The present studies were designed to provide information that will aid future research in this area in both human and animal models. The objectives of these studies were (1) to evaluate the efficacy of different doses and durations of succimer (meso-2,3-dimercaptosuccinic acid; DMSA) chelation for reducing brain and blood Pb levels and (2) to determine the extent to which blood Pb can serve as a surrogate of brain Pb following chelation. Long-Evans hooded rats were exposed to Pb from birth until day 31 (Study 1) or day 40 (Study 2) of life, followed by oral treatment with a vehicle or one of two succimer regimens for a duration of either 7 or 21 days. Results indicated that 7 days of succimer treatment produced a 1.5- to 2.5-fold greater reduction of Pb in blood than in brain, relative to time-matched vehicle groups. Prolonged treatment (21) days did not further reduce blood Pb levels (relative to 7-day succimer treatment), but did produce further reductions in brain Pb level compared to time-matched vehicle groups. Thus, chelation-mediated reductions in brain Pb did not parallel reductions in blood Pb over the course of treatment. While the relevance of these data to humans may be confounded by anatomical and physiological differences between rodents and primates, as well as differences in the metabolism of succimer (DMSA), they suggest that clinical studies should exercise caution when using blood Pb as an index of the efficacy of chelation treatment for reducing brain Pb levels.

Intensive chemotherapy and bone marrow rescue for young children with newly diagnosed malignant brain tumors

PURPOSE

To evaluate a strategy that avoids radiotherapy in children less than 6 years of age with newly diagnosed malignant brain tumors, by administering myeloablative consolidation chemotherapy with autologous bone marrow reconstitution (ABMR) after maximal surgical resection and conventional induction chemotherapy.

PATIENTS AND METHODS

Between March 1991 and April 1995, 62 children (median age, 30 months) with newly diagnosed malignant brain tumors were enrolled onto this trial. Children received conventional induction chemotherapy with vincristine, cisplatin, cyclophosphamide, and etoposide, repeated every 3 weeks for five cycles. Children without disease progression on induction chemotherapy were offered consolidation with myeloablative chemotherapy that incorporated carboplatin, thiotepa, and etoposide followed by ABMR. Irradiation was used only for residual tumor at consolidation or for progressive/recurrent disease.

RESULTS

Induction chemotherapy was well tolerated by most patients; however, progression was noted in 17 children (27%) and four (6%) died of treatment complications. Of 37 children who received consolidation chemotherapy with ABMR, 15 are free of disease progression (median post-ABMR without further treatment, >44 months). The remaining 22 all progressed within 15 months of ABMR; three of 37 (8%) died of treatment-related complications. The 3-year overall survival (OS) and event-free survival (EFS) rates from diagnosis for all children are 40% (95% confidence interval [CI], 28% to 52%) and 25% (95% CI, 13% to 37%), respectively. Radiotherapy was administered to 19 of 62 children: 17 for progressive disease (PD) and two for residual disease at the time of ABMR.

CONCLUSION

A significant proportion of children with malignant brain tumors can avoid radiotherapy and prolonged maintenance chemotherapy yet still achieve durable remission with this brief intensive chemotherapy regimen.

Immunocytochemical detection of the neurokinin B receptor (NK3) on melanin-concentrating hormone (MCH) neurons in rat brain

The presence of the neurokinin B receptor (NK3 receptor) in the rat lateral hypothalamus and the zona incerta was previously reported. The aim of the present study was to define its cellular localization in these areas. Investigations, coupling immunocytochemical and in situ hybridization techniques, focussed on two neuron populations: the melanin-concentrating hormone (MCH) neurons and a population of neurons recognized by an ovine prolactin antiserum (PRL-ir neurons). While PRL-ir neurons did not exhibit NK3 immunoreactivity, 57% +/- 6% of MCH neurons were strongly stained by the NK3 antiserum. These results suggest that neurokinin B is involved in the regulation of MCH neuron activity via the NK3 receptor; they provide new bases for further investigations on MCH role in the control of food and water intake.

Variability in salt sensitivity classifications in black male versus female adolescents

Salt sensitivity (changes in blood pressure in response to alterations in salt intake) may be a risk factor for hypertension. In the present study, we examined the prevalence of salt sensitivity based on two different classifications in healthy black male and female adolescents (aged 13 to 16 years). A total of 135 black adolescents participated in a 50 mmol/24 h low sodium diet for 5 days and a 150 mmol/24 h NaCl supplement for 10 days. Dietary compliance was defined as sodium excretion less than or equal to 50 mmol/24 h for the low sodium diet and greater than or equal to 165 mmol/24h for the high NaCl supplement. Salt sensitivity was defined by two classifications: (1) as a decrease in mean blood pressure greater than or equal to 5 mm Hg from baseline to the low sodium diet, and (2) as an increase in mean blood pressure greater than or equal to 5 mm Hg from the low sodium diet to the high NaCl supplement. With classification 1, 14% of boys were identified as salt sensitive compared with 22% of girls. With classification 2, however, 31% of boys were identified as salt sensitive compared with 18% of girls. Analyses based on changes in systolic pressure demonstrated similar findings across sex, although overall classifications based on systolic pressure yielded a greater percentage of salt-sensitive subjects. These sex differences in classification patterns were not due to differences in other important variables, such as changes in sodium excretion, potassium excretion, or Quetelet index. These results suggest that the prevalence of salt sensitivity differs by sex depending on the type of protocol used for the classification of salt sensitivity in a black pediatric population.

Molecular analysis of the replication elements of the broad-host-range RepA/C replicon

RepA/C is a replicon specific to the IncA/C incompatibility group of plasmids and was isolated recently from plasmid RA1. The sequence of this autoreplicative region was established; it contains 13 repeats, suggesting that the replicon uses iterons to control its copy number. The sequence contains two ORFs, one potentially coding for a 33-kDa protein (ORF1) and a second potentially coding for a 14-kDa protein (ORF2) (Llanes et al., 1994b). In this work, using an in vitro transcription/translation system, we detected a polypeptide whose size corresponded well to that of the deduced product of ORF1. Deletion and insertion mutation analysis showed that ORF1 is essential for replication; it encodes an initiator protein (called RepA). ORF2 was not essential for replication in Escherichia coli and its function remains to be determined. Using complementation experiments, the replication origin (ori) of RepA/C was defined. The ori was located in a 600-bp fragment downstream from repA, containing 10 direct repeats. To study the control of repA expression, a transcriptional fusion PrepA::lacZ was constructed. Its analysis showed that repA is transcriptionally autoregulated as are most repA genes of replicons controlled by iterons.

Community hospital administration of intravenous tissue plasminogen activator in acute myocardial infarction: improved timing, thrombolytic efficacy and ventricular function

As an investigational fibrinolytic agent for acute myocardial infarction, intravenous recombinant tissue-type plasminogen activator (rt-PA) has been administered primarily in tertiary care and university centers. To determine the value of early initiation of such therapy, two satellite community hospital emergency rooms were established for use of rt-PA and the experience was compared among 142 consecutive patients who were transferred to a regional center for acute cardiac catheterization after intravenous rt-PA therapy. In Group I (n = 19), patients received rt-PA after interhospital transport to the regional center, but before cardiac catheterization. In Group II (n = 70), rt-PA therapy was initiated by the helicopter physician and nurse team after their arrival at the local community hospital emergency room. Group III patients (n = 53) had rt-PA administered in the local community hospital by the emergency room physician. Group III patients had earlier initiation of therapy (2.1 +/- 0.8 hours in Group III versus 3.8 +/- 1.2 hours in combined Groups I and II, p less than 0.001) and an increased rate of infarct vessel recanalization on the 90 minute coronary angiogram (81 in Group III versus 67% in combined Groups I and II, p = 0.057). The patients in Group III had a higher acute left ventricular ejection fraction (54 +/- 8% versus 50 +/- 9.5% in combined Groups I and II, p less than 0.01) and a trend toward an increased 7 day ejection fraction (55.5 +/- 9% versus 51.7 +/- 9.5%, respectively, p = 0.08).(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical significance of ventricular ectopic beats in the early posthospital phase of myocardial infarction

The clinical significance of ventricular ectopic beats in the posthospital phase of myocardial infarction was studied in 272 patients aged 65 years or less who were followed up for 1 year after the infarction. Ventricular ectopic beats, identified in 6 hour electrocardiographic tape recordings, obtained before hospital discharge (study 1) and 5 months after discharge (study 2) increased in frequency and complexity in the 5 month interval. Ventricular ectopic beats at a rate of 20 or more per hour recorded before discharge were associated with complex ventricular ectopic patterns in the same 6 hour recording and with frequent (20 or more per hour), early cycle and bigeminal patterns in recordings mad 5 months later. Analysis with log-linear modeling indicated that the occurrence of complex ventricular ectopic beats at follow-up examination was associated with the concomitant use of antiarrhythmic agents,but not with use of digitalis, propranolol or tranquilizers. A ventricular ectopic beat frequency of 20 or more per hour at discharge was associated with increased (P less than 0.05) cardiac mortality in the initial 0 to 4 months after discharge but not in the subsequent 8 months; ectopic beats recorded in the 5 month follow-up study were not associated with increased cardiac mortality in the subsequent 5 to 12 months. The prognostic significance of ventricular ectopic beats is discussed in the light of these findings.

The early posthospital phase of myocardial infarction. Prognostic stratification

Prognostic stratification was carried out on 518 patients less than or equal to 65 years of age who were discharged from the hospital following a definite or probable acute myocardial infarction and followed for four months. The total population was made up of 272 patients hospitalzed in 1973 and 246 patients hospitalized in 1974; one hundred and forty-two variables were collected on each patient. The clinical characteristics of the 1973 and 1974 populations were remarkably similar, and both groups had a four-month posthospital cardiac mortality rate of 4%. Two prognostic stratification schemes were developed on the 1973 population which identified low and high risk groups with meaningfully different four-month cardiac death rates. Both stratification schemes were tested on the 1974 population, and one of the two schemes was validated as identifying a significantly increased cardiac mortality rate in the high as opposed to the low risk group. The four-month posthospital cardiac mortality rate was 3% in the low and 14% in the high risk group (Z = 2.70, P less than 0.003). The high risk group was characterized by two or more of the following characteristics: 1) history of angina at ordinary levels of activity or at rest; 2) CCU hypotension and/or congestive heart failure; 3) ventricular premature beat frequency greater than or equal to 20/hr on a six-hour electrocardiographic tape recording. The low risk group had none or only one of the above characteristcis. The prognostic power of this stratification scheme is such that sixteen percent of the posthospital population can be identified as high risk, and this subgroup contains forty-six percent of the patients who die of cardiac cause in the four-month posthospital interval.