Brain abscesses in cyanotic heart disease

Sixty cases of brain abscesses in patients with cyanotic heart disease is reported. Forty four (73.3%) belonged to pediatric age group. There was only single case of infratentorial abscess located in the cerebellar paravermian region. The abscesses were multiloculated in 42%, multiple in 10% and solitary in 48% cases. Streptococci was the commonest (77%) micro-organism isolated from pus culture. Forty eight patients were treated by aspiration through twist drill, 7 patients conservatively and 5 had primary excision of abscesses. Forty four patients improved in their neurological status, three had fixed neurological deficits and 5 patients deteriorated further. There were 8 deaths. Complication like cyanotic spells was recorded in 17% cases treated by aspiration. None of the patients treated by twist drill aspiration had seizure. It is suggested that aspiration of abscesses through twist drill hole and antibiotic therapy could be the treatment of choice. Vascular slowing in a localised area resulting in infraction and thus preparing the focus for abscess formation is the possible mechanism in the evolution of these abscesses.     

Impairment of executive function induced by hypertension in the rhesus monkey (Macaca mulatta)

The effects of chronic, untreated hypertension on executive function were investigated in a nonhuman primate model of hypertensive cerebrovascular disease. Executive function was assessed with the Conceptual Set-Shifting Task (CSST). a task adapted from the human Wisconsin Card Sorting Test (WCST). Like the WCST, the CSST requires abstraction of a stimulus set, followed by a series of set shifts. Performance on the CSST by 7 young adult monkeys (Macaca mulatta) with surgically induced hypertension was compared with that of 6 normotensive monkeys. The hypertensive group was significantly impaired relative to the normotensive group in abstraction and set shifting. Although the neural basis of this impairment is unclear, evidence from studies with humans and monkeys suggests that the prefrontal cortex may be the locus for this effect of hypertension.     

Intravascular circulation and distribution of human 51Cr-DBBF stroma-free hemoglobin, 51Cr-plasma, 51Cr-saline, 59FE-plasma, and 125I-albumin in the mouse

Male B6C3HF1 mice were infused with human 51Cr-labeled DBBF (bis 3,5-dibromosalicyl fumarate) crosslinked stroma-free hemoglobin (SFH). In the first hour following SFH infusion, 11.2% of the infused radioactivity was found in the skin, 11.4% in muscle, 9.1% in the skeleton, and 5% in the liver. Twenty-four hours after infusion, 15.4% of the radioactivity was found in the skin, 10.3%, in the muscle, 16.6% in the skeleton, and 6.7% in the liver. The circulation and distribution of 51Cr-labeled DBBF-SFH were compared with levels of 51Cr labeled plasma, 51Cr in saline, 59Fe labeled plasma, and 125I albumin. The radioactivity in the blood was similar for 51Cr-DBBF-SFH, 51Cr-plasma, and 59Fe-plasma. During the 24-hour post-infusion period, extravascular distribution of the 51Cr-saline, 51Cr-plasma, and 125I albumin within the organs was similar to that of 51Cr-DBBF-SFH, with the highest levels being in skin, muscle, skeleton and liver, and no increase in the levels in the lung or spleen. The distribution of 59Fe compared to that of 51Cr-DBBF, 51Cr-plasma, 51Cr-saline, and 125I albumin can be explained by the fact that 59Fe is utilized in the production of new red blood cells.     

Gamma-knife radiosurgery for trigeminal neuralgia

Gamma knife was installed at the PD Hinduja National Hospital and Medical Research Centre, Mumbai, India, in January 1997. In the first year of gamma-knife radiosurgery to January 1998, we treated 110 patients, of whom six had medically refractory trigeminal neuralgia. Seven treatments were administered to this group of six patients (one had bilateral neuralgia). This report evaluates the effectiveness of radiosurgery treatment in these patients. The median age of the patients was 56 years and there were five males and one female. Following Leksell stereotactic frame fixation, a magnetic resonance imaging scan was done in all. The Leksell gamma plan was used for planning. A radiosurgery dose of 70–80 Gy was delivered to the trigeminal root entry zone, 2–4 mm anterior to the junction of the pons and trigeminal nerve with a single 4 mm collimator helmet. Complete pain relief was achieved in four patients. Two had partial relief. No patient developed any radiosurgery related morbidity during the follow-up period of 5–16 months. Radiosurgery seems to be an effective approach for medically or surgically refractory trigeminal neuralgia.     

Infusible platelet membrane microvesicles: a potential transfusion substitute for platelets

BACKGROUND: Several substitutes for intact, viable platelets have been used for transfusion, both to people and in animal models, with varied success. Infusible platelet membrane (IPM) is prepared from human platelets. IPM retains the glycoprotein (GP)lb receptor and has platelet factor 3 activity (procoagulant activity). However, factor V, serotonin, a cytoplasmic marker enzyme (purine nucleotide phosphorylase), GPIIb/IIIa complex, and HLA class I and II antigens are all absent in IPM. STUDY DESIGN AND METHODS: IPM is prepared from outdated platelets. The platelets were disrupted by freezing and thawing; they were washed and heated to inactivate possible viral contaminants, and then the sonicated membrane microvesicle fraction was separated and lyophilized. The hemostatic activity of IPM was measured by its ability to reduce the prolonged bleeding time in thrombocytopenic rabbits. RESULTS: Administration of IPM at a dose of 2 mg per kg results in a substantial reduction in the bleeding time. In a series of 23 experiments, a median preinjection bleeding time of 15 minutes was reduced to 6 minutes within 4 hours after IPM administration. Administration of IPM did show a mild enhancement in the thrombogenicity index, as measured in the Wessler rabbit model. This enhancement is, however, not significant, as a thrombogenicity index value of up to 0.6 is clinically acceptable. CONCLUSION: IPM may have clinical potential as a substitute for platelets in the treatment of bleeding due to thrombocytopenia.     

Cerebrospinal fluid profile of amyloid β42 (Aβ42), hTau and ubiquitin in North Indian Alzheimer's disease patients

Alzheimer's disease (AD) is the most common form of dementia, and is characterized by the degeneration of neurons and their synapses, and a higher number of amyloid plaques and neurofibrillary tangles (NFTs) compared with that found in non-demented individuals. Amyloid-β-peptides (Aβ) are major components of amyloid plaques in AD brain whereas NFTs are composed of Tau and associated with ubiquitin. The aim of the present study was to analyze the levels of Aβ42, hTau (total Tau) and ubiquitin in CSF of North Indian population. CSF Aβ42, Tau and ubiquitin were measured in CSF of AD patients as well as controls using ELISA assays. Here we report low Aβ42 levels in AD patients (324.24 ± 76.38 pg/ml) as compared to those in non-AD (NAD) (668.34 ± 43.13 pg/ml), neurological controls (NCs) (727.28 ± 46.49 pg/ml) and healthy controls (HCs) (976.47 ± 124.46 pg/ml). In contrast, hTau and ubiquitin levels were significantly high (568.65 ± 48.89 pg/ml and 36.82 ± 4.34 ng/ml, respectively) in AD patients compared to those in NAD, NC and HC. The hTau levels were 267.37 ± 36.64 pg/ml, 167.34 ± 44.27 pg/ml and 107.62 ± 24.27 pg/ml in NAD, NC and HC, respectively. Similarly, ubiquitin levels were 23.57 ± 2.32 ng/ml, 19.76 ± 3.64 ng/ml and 13.24 ± 4.56 ng/ml in NAD, NC and HC, respectively. In conclusion, low Aβ42 and high Tau–ubiquitin levels were found in North Indian AD patients.