Metabotropic glutamate receptors drive the endocannabinoid system in hippocampus

Endocannabinoids are key intercellular signaling molecules in the brain, but the physiological regulation of the endocannabinoid system is not understood. We used the retrograde signal process called depolarization-induced suppression of inhibition (DSI) to study the regulation of this system. DSI is produced when an endocannabinoid released from pyramidal cells suppresses IPSCs by activating CB1R cannabinoid receptors located on inhibitory interneurons. We now report that activation of group I metabotropic glutamate receptors (mGluRs) enhances DSI and that this effect is blocked by antagonists of both mGluRs and of CB1R. We also found that DSI is absent in CB1R knock-out (CB1R(-/-)) mice, and, strikingly, that mGluR agonists have no effect on IPSCs in these mice. We conclude that group I mGluR-induced enhancement of DSI, and suppression of IPSCs, is actually mediated by endocannabinoids. This surprising result opens up new approaches to the investigation of cannabinoid actions in the brain.

Celiac disease presenting as iron-deficiency anemia in northern India

BACKGROUND

Adult celiac disease is infrequent in India. Iron-deficiency anemia as its presenting manifestation is still rarer.

METHODS

We investigated patients with refractory iron-deficiency anemia attending the hematology clinic of a tertiary-care hospital for celiac disease. The diagnosis of celiac disease was based on histology, serology and response to treatment.

RESULTS

Of 19 patients with refractory iron-deficiency anemia seen from April 1998 to March 2000, 11 were diagnosed to have celiac disease. Four of these had abnormal D-xylose test and 3 had fat malabsorption. All 11 patients responded to gluten-free diet with improvement in hematological parameters.

CONCLUSION

Patients with refractory iron-deficiency anemia of unknown cause should be investigated for subclinical celiac disease.

Hyposplenism in alcoholic cirrhosis, facts or artifacts? A comparative analysis with non-alcoholic cirrhosis and extrahepatic portal venous obstruction

BACKGROUND AND AIMS

Hyposplenism has been described in patients with alcoholic cirrhosis (AC). However, no data are available regarding hyposplenism in patients with non-alcoholic cirrhosis (NAC) and other forms of portal hypertension such as extrahepatic portal venous obstruction (EHPVO). The aim is to study the splenic functions in patients with AC, NAC, and EHPVO.

METHODS

Splenic functions were assessed consecutively in 22 patients with AC, 21 with NAC, and 23 with EHPVO. The tests included pitted red blood cells (RBC; %) and Howell-Jolly bodies in the peripheral smear. Pitted RBCs > 2% with or without the presence of Howell-Jolly bodies were taken as indicators of hyposplenism. The splenic function in each group was compared with age-matched controls.

RESULTS

Hyposplenism was found in 10 (45.45%) patients with AC, six (28.57%) with NAC and one (4.34%) with EHPVO. The mean pitted RBCs were significantly increased in patients with AC (mean 4.93 +/- 1.36% vs control 1.22 +/- 0.17%, P < 0.05), but not so with NAC (2.01 +/- 0.69%) and EHPVO (mean 0.99 +/- 0.1% vs control 0.66 +/- 0.1%, P > 0.05). Howell-Jolly bodies were seen in only four patients. The mean pitted RBCs were significantly higher among patients who were actively consuming alcohol (9.14 +/- 3.35%) compared to those who abstained at least for more than 24 weeks (2.0 +/- 1.3%, P < 0.05).

CONCLUSION

Hyposplenism is more common in AC patients, particularly those who are actively consuming alcohol compared with those who abstain. Patients with NAC have a lower incidence of hyposplenism, while in EHPVO patients, it is uncommon.

Left ventricular diastolic dysfunction during demand ischemia: rigor underlies increased stiffness without calcium-mediated tension. Amelioration by glycolytic substrate

OBJECTIVES

The goal of this study was to determine the subcellular mechanism(s) underlying increased left ventricular (LV) diastolic chamber stiffness (DCS) during angina (demand ischemia).

BACKGROUND

Increased DCS may result from increased diastolic myocyte calcium concentration and/or rigor. Therefore, we assessed the effects of direct alterations of both calcium-activated tension and high-energy phosphates on increased DCS.

METHODS

Demand ischemia was reproduced in isolated, isovolumic, red-cell perfused rabbit hearts by imposing low-flow ischemia and pacing tachycardia. This resulted in increased DCS. Interventions were performed after LV end-diastolic pressure had increased approximately 7 mm Hg. Initially, to determine the effects of altered calcium concentration or myofilament calcium responsiveness, hearts received either: 1) 5 or 14 mmol/L calcium chloride; 2) 8 mmol/L egtazic acid; 3) 5 mmol/L butane-dione-monoxime (BDM); or 4) 50 mmol/L ammonium chloride (NH4Cl). Then, to assess the contribution of decreased high-energy phosphate supply, hearts received 5) glucose (25 mmol/L) and insulin (400 microU/ml).

RESULTS

1) Calcium chloride, 5 and 14 mmol/L, increased LV systolic pressure by 42% and 70%, respectively (p < 0.001), indicating increased calcium-activated tension, but did not further increase DCS, implying intact diastolic calcium resequestration. 2) Egtazic acid reduced LV systolic pressure by 30% (p < 0.001), indicating reduced intracellular calcium, but failed to reduce increased DCS. 3) Butane-dione-monoxime and NH4Cl chloride affected contractile function (i.e., a calcium-driven force) but did not alter increased DCS. 4) Glucose and insulin, which increase high-energy phosphates during ischemia, reduced increased DCS by 50% (p < 0.001).

CONCLUSIONS

Increased DCS during demand ischemia was insensitive to maneuvers altering intracellular calcium concentration or myofilament calcium-responsiveness, that is, evidence against an etiology of calcium-activated tension. In contrast, increased glycolytic substrate ameliorated increased DCS, supporting a primary mechanism of rigor-bond formation.

Acute erythroleukemia (AML-M6)--a study of clinicohematological, morphological and dysplastic features in 10 cases

Acute erythroleukemia is a relatively rare form of acute myelogenous leukemia. In the present study we analysed ten cases of acute erythroleukemia. All the patients were anemic and nine were thrombocytopenic at the time of diagnosis. Peripheral blood showed blasts in nine cases. Dyserythropoiesis was seen in all the cases whereas dysmegakaryopoiesis was seen in five cases. Dysplasia in the granulocytic series was seen in five cases. Based on the overall features this study concludes that acute erythroleukemia is associated with dysplasia of variable degree.

Central venous access resulting in selective failure of ICD defibrillation capacity

In a patient with a defibrillator system incorporating a lead with integrated bipolar sensing, physical contact between a guidewire (inserted for venous access) and the right ventricular defibrillation coil created sensing artefacts that triggered an inappropriate discharge. The presence of the guidewire in the heart during the discharge resulted in an electrical short with irreversible damage to the generator and rendered it incapable of delivering further high voltage therapy.

Lack of direct role for calcium in ischemic diastolic dysfunction in isolated hearts

BACKGROUND

Ischemia is characterized by an increase in intracellular calcium and occurrence of diastolic dysfunction. We investigated whether the myocyte calcium level is an important direct determinant of ischemic diastolic dysfunction.

METHODS AND RESULTS

We exposed isolated, perfused isovolumic (balloon in left ventricle) rat and rabbit hearts to low-flow ischemia and increased extracellular calcium (from 1.5 to 16 mmol/L) for brief periods. Intracellular calcium was measured by aequorin. Low-flow ischemia resulted in a 270% increase (P:<0.05) in diastolic intracellular calcium, a 50% (P:<0.05) calcium transient amplitude decrease, and a 52% (P:<0.05) slowing of calcium transient decline. Diastolic pressure increased by 6+/-2 mm Hg (P:<0.05), and rate of systolic pressure decay decreased by 65% (P:<0.05). Experimentally increasing extracellular calcium doubled both intracellular diastolic calcium and calcium transient amplitude, concomitant with a developed pressure increase; however, there was no increase in ischemic diastolic pressure, slowing of the calcium transient decay, or further slowing of systolic pressure decay. Similarly, after 45 minutes of low-flow ischemia, after diastolic pressure had increased from 8.5+/-0.6 to 19.7+/-3.5 mm Hg (P:<0.001), intracoronary high-molar calcium chloride infusion increased systolic pressure from 36+/-4 to 63+/-11 mm Hg (P:<0.001), indicating an increase in intracellular calcium, but it decreased diastolic pressure from 19. 7+/-3.5 to 17.5+/-3.7 mm Hg (P:<0.01). Conversely, EGTA infusion decreased systolic pressure, indicating a decrease in intracellular calcium, but did not decrease diastolic pressure.

CONCLUSIONS

When calcium availability was experimentally altered during ischemia, there was no alteration in left ventricular diastolic pressure, suggesting that ischemic diastolic dysfunction is not directly mediated by a calcium activated tension.

Serum ferritin level as a marker of preterm labor

OBJECTIVE

To compare the serum ferritin levels in women with preterm labor (PTL) or preterm premature rupture of membranes with those in normal gravid women.

METHOD

The study group consisted of 50 consecutive subjects with preterm labor and 49 subjects with preterm premature rupture of membranes (PROM). The control group consisted of 50 subjects matched with the study group for hemoglobin (Hb) and gestation who did not have PTL or preterm PROM. Serum ferritin levels were assayed in both the groups.

RESULTS

Mean serum ferritin levels in patients with preterm labor and preterm premature rupture of membranes were 23.24+/-12.13 ng/ml and 29.44+/-28.41 ng/ml, respectively. The mean serum ferritin in control subjects was 8.69+/-3.7 ng/ml. The difference was evaluated by Student's t-test and was found to be statistically significant.

CONCLUSION

The serum ferritin level is significantly raised in pregnant women with preterm labor and preterm PROM.

Expression of receptor-Ck and SREBP genes in mononuclear cells from acute leukemia patients

We have recently shown that Receptor-Ck regulated genes, involved in cellular growth and death through a transcriptional factor (SREBP) which has affinity for sterol regulatory element (SRE) present in the promoter region of these genes. The present study revealed that blasts, derived from both ALL and AML patients, were unable to express SREBP gene product although they had the capacity to express Receptor-Ck gene product. These results which depict defective Receptor-Ck-dependent signalling are in conformity with our previous results which showed that lymphocytes from CML patients as well as other human leukemic cell lines are unable to express gene coding for Receptor-Ck leading again to a state of impaired Receptor-Ck-dependent signalling. On the basis of these results, we propose that deregulated Receptor-Ck-dependent signalling may have an important role in leukemogenesis.

Paterson-Kelly syndrome and celiac disease--a rare combination

Paterson-Kelly syndrome is characterized by an association of iron deficiency with dysphagia. We describe a patient with this syndrome who was later diagnosed to have celiac disease.

Cryptococcal prostatitis in a patient with chronic lymphocytic leukemia

Cryptococcosis is a systemic mycosis usually affecting patients of immunodeficiency i.e. transplants recipients, patients on chemotherapy for neoplastic diseases and in those suffering from human immunodeficiency virus infection. We report a 52-year old male suffering from chronic lymphocytic leukemia (CLL) on chemotherapy who presented with fever and features of prostatism. Cryptococcus neoformans infection (CN) was diagnosed on aspiration of a prostatic nodule. Subsequent investigations revealed a disseminated involvement by cryptococcus. The case represents an unusual presentation of disseminated cryptococcosis.

Increased diastolic chamber stiffness during demand ischemia: response to quick length change differentiates rigor-activated from calcium-activated tension

BACKGROUND

Increased diastolic chamber stiffness (increased DCS) during angina (demand ischemia) has been postulated to be generated by increased diastolic myocyte calcium concentration.

METHODS AND RESULTS

We reproduced demand ischemia in isolated isovolumically contracting red-cell-perfused rabbit hearts by imposing pacing tachycardia during global low coronary blood flow (32% of baseline). This increased lactate production without increasing oxygen consumption and resulted in increased DCS (isovolumic left ventricular end-diastolic pressure [LVEDP] increased 10 mm Hg, P<0. 001, n=38). To determine the mechanism of increased DCS, we assessed responses to a quick-stretch-release maneuver (QSR), in which the intraventricular balloon was rapidly inflated and deflated to achieve a 3% circumferential muscle fiber length change. QSR was first validated as an effective method of discriminating between calcium-driven and rigor-mediated increased DCS. QSR imposed during demand ischemia when DCS had increased (LVEDP pretachycardia versus posttachycardia, 15+/-1 versus 27+/-2 mm Hg, P<0.001, n=6) reduced DCS to pretachycardia values (LVEDP post-QSR, 15+/-1 mm Hg, P<0.001), ie, elicited a response characteristic of rigor, without any component of calcium-generated tension.

CONCLUSIONS

A rigor force, possibly resulting from high-energy phosphate depletion and/or an increase in ADP, appears to be the primary mechanism underlying increased DCS in this model of global LV demand ischemia.

Impaired lusitropy-frequency in the aging mouse: role of Ca(2+)-handling proteins and effects of isoproterenol

We examined the relationship between age-associated lusitropic impairment, heart rate, and Ca(2+)-handling proteins and assessed the efficacy of increasing left ventricular (LV) relaxation via beta-adrenergic stimulation in adult and aging mouse hearts. LV function was measured in isolated, isovolumic blood-perfused hearts from adult (5 mo), old (24 mo), and senescent (34 mo) mice. Hearts were paced from 5 to 10 Hz, returned to 7 Hz, exposed to 10(-6) M isoproterenol, and paced again from 7 to 10 Hz. Age-related alterations in Na(+)/Ca(2+) exchanger (NCX), sarcoplasmic reticulum (SR) Ca(2+)-ATPase (SERCA2a), and phospholamban (PLB) levels were assessed by immunoblot. Despite preserved contractile performance, aging caused impaired lusitropy. Increased pacing caused an elevation in end-diastolic pressure that progressively worsened with age. The time constant of isovolumic pressure decay (tau) was significantly prolonged in old and senescent hearts compared with adults. Relative to adult hearts, the SERCA2a-to-PLB ratios were reduced 68 and 69%, and NCX were reduced 37 and 58% in old and senescent hearts, respectively. Isoproterenol completely reversed the age-associated lusitropic impairments. These data suggest that impaired lusitropy in aging mouse hearts is related to a decreased rate of cytosolic Ca(2+) removal and that accelerating SR Ca(2+) resequestration via beta-adrenergic stimulation can reverse this impairment.

Value of inpatient diagnostic CCTV-EEG monitoring in the elderly

PURPOSE

To examine the outcome of inpatient diagnostic closed circuit TV-EEG (CCTV-EEG) monitoring in a consecutive series of elderly patients admitted to an adult epilepsy-monitoring unit (EMU) over a continuous 6-year period.

METHODS

Retrospective review of all admissions to a university hospital adult EMU. Those older than 60 years were identified. Patients who were monitored for status epilepticus were excluded. Data on duration of events, frequency of events, physical examination, medications, preadmission EEG, brain imaging, length of stay, and interictal and ictal EEG were obtained.

RESULTS

Of the 18 patients admitted for monitoring only, mean age was 69.5 years (range, 60-90 years). Mean length of stay was 4.3 days (range, 2-9 days). Five patients had complex partial seizures recorded. Three patients, all treated with anti-epileptic drugs (AEDs), had no spells recorded, and no additional diagnostic information was gained from the admission. The other 10 patients, eight of whom had been treated with AEDs, were symptomatic during their admission, leading to a variety of neurologic but not epileptic, psychiatric, or other medical disorders, and allowing tapering of AEDs.

CONCLUSIONS

In elderly patients with suspected epilepsy, CCTV-EEG is a very useful diagnostic tool. In this series of 18, 10 patients were diagnosed with potentially treatable medical illnesses not responsive to AEDs.

X-linked dyskeratosis congenita is predominantly caused by missense mutations in the DKC1 gene

Dyskeratosis congenita is a rare inherited bone marrow-failure syndrome characterized by abnormal skin pigmentation, nail dystrophy, and mucosal leukoplakia. More than 80% of patients develop bone-marrow failure, and this is the major cause of premature death. The X-linked form of the disease (MIM 305000) has been shown to be caused by mutations in the DKC1 gene. The gene encodes a 514-amino-acid protein, dyskerin, that is homologous to Saccharomyces cerevisiae Cbf5p and rat Nap57 proteins. By analogy to the homologues in other species, dyskerin is predicted to be a nucleolar protein with a role in both the biogenesis of ribosomes and, in particular, the pseudouridylation of rRNA precursors. We have determined the genomic structure of the DKC1 gene; it consists of 15 exons spanning a region of 15 kb. This has enabled us to screen for mutations in the genomic DNA, by using SSCP analysis. Mutations were detected in 21 of 37 additional families with dyskeratosis congenita that were analyzed. These mutations consisted of 11 different single-nucleotide substitutions, which resulted in 10 missense mutations and 1 putative splicing mutation within an intron. The missense change A353V was observed in 10 different families and was shown to be a recurring de novo event. Two polymorphisms were also detected, one of which resulted in the insertion of an additional lysine in the carboxy-terminal polylysine domain. It is apparent that X-linked dyskeratosis congenita is predominantly caused by missense mutations; the precise effect on the function of dyskerin remains to be determined.

Disseminated histoplasmosis 19 years after renal transplantation

Infections with fungi like Histoplasma are rarely seen in immunocompromized patients. We report the case of a renal transplant recipient who presented with fever and was diagnosed to have disseminated histoplasmosis 19 years after transplant. The pitfalls in making a diagnosis in non-endemic areas are discussed. The literature on renal transplantation recipients with histoplasmosis has been reviewed.

Molecular mechanism involved in TPA-induced myelopoietic programming

The study, addressed to understand the mechanism responsible for 12-O-tetradecanoyl phorbol-13-acetate (TPA)-induced myeloid differentiation, revealed that the inherent capacity of TPA to induce expression of Receptor-C(K) in HL-60 cells (which are unable to express Receptor-C(K) in their native state) is responsible for its ability to induce phenotypic differentiation of HL-60 cells. Based upon these results, we propose that Receptor-C(K) dependent signalling is the Critical 'Molecular Switch' responsible for TPA-induced myelopoietic programming.