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S Siddique

Publications and source records attributed to S Siddique.

13 recordsLinked to original sources
PubMed2001

Comparison of protein carbonyl and antioxidant levels in brain tissue from intracerebral haemorrhage and control cases.

BACKGROUND: In an attempt to develop a clearer understanding of the pathological mechanisms underlying intracerebral haemorrhage (ICH), the objective of this investigation was to obtain evidence for free radical-induced oxidative damage in brain tissue following intracerebral haemorrhage. METHODS: Brain cortex samples were obtained from the ischaemic penumbra (overlying the haematoma) from 10 patients with spontaneous ICH and from six control cases (normal tissue obtained during tumour removal or aneurysm repair). Following extraction via homogenization and subsequent derivatization with dinitrophenylhydrazine (DNPH), tissue samples were analysed for the presence of protein carbonyl moieties (a hallmark of tissue protein oxidation). This procedure involved SDS-polyacrylamide gel electrophoresis and Western immunoblotting using a commercially available primary monoclonal antibody to DNPH, with final visualization of oxidized protein bands via enhanced chemiluminescence. RESULTS: Samples from ICH cases showed a number (10-15) of well-defined bands of medium to strong staining intensity (not present in nonderivatized samples), corresponding to proteins of molecular mass 25-200 kDa, indicating the presence of oxidatively damaged proteins in these samples. However, tissue samples from control cases also showed the presence of oxidized protein bands, with fractionation patterns for individual ICH or control samples being qualitatively and quantitatively similar. In addition, there was no significant difference in the levels of the following antioxidants (as additional indirect markers of free radical activity) in ICH or control brain tissue: glutathione, glutathione peroxidase, glutathione reductase, catalase, superoxide dismutase, and total antioxidant status. CONCLUSIONS: It is concluded from the above data that (i) evidence for free radical involvement in ICH based on protein carbonyl analysis should be interpreted with caution, since normal brain tissue contains a surprisingly high proportion of oxidized proteins; (ii) since there is no evidence for increased protein oxidative damage or decreased tissue antioxidant levels in ICH, therapeutic strategies aimed at salvage of potentially viable tissue would not benefit from inclusion of protein protecting antioxidants.

Antioxidants↗
PubMed2000

Paecilomyces fungus infection of the paranasal sinuses.

Fungal infections caused by Paecilomyces species are very rare and occur in adult patients with impaired host defences or following foreign body implants. They are found worldwide in soil and decaying vegetation. We describe a case of an 8 year old child who came with complaints of left sided nasal obstruction and discharge, telecanthus, diplopia and epiphora. On examination and investigation he had pansinusitis caused by P. lilacinus. An endoscopic sinus surgery was done and the patient was on oral Itraconazole for 6 months. To our knowledge, this is the first case reported in the paediatric age group.

Antifungal Agents↗
PubMed2000

Continuous monitoring of ICP and CPP following ICH and its relationship to clinical, radiological and surgical parameters.

Sixty-two patients with a spontaneous supratentorial haemorrhage had continuous Intracranial Pressure (ICP) and Cerebral Perfusion Pressure (CPP) monitoring. In addition to the recordings of physiological data their past medical history, presenting neurological state, Computed Tomograph (CT) findings, daily Glasgow Coma Score (GCS) and outcome were noted. The mean age was 57.6 years (sd 13.3). Onset of recording, after ictus was at a mean of 32.6 hours (sd 26.0). Average length of recording was 62.0 hours (sd 39.8). Thirty-one patients had evacuation of haematoma, 6 insertion of External Ventricular Drain (EVD). Preoperative measures of ICP were significantly related to delayed neurological deterioration, death within three days and Glasgow Outcome Scale (GOS) at neurosurgical discharge. No such relationships existed with preoperative measures of CPP and neither ICP nor CPP was related to outcome at 6 months. Post-operative measures of both ICP and CPP demonstrated a significant relationship with death within three days of ictus and GOS at neurosurgical discharge. Again no relationship existed with these parameters and outcome at six months. Surgical evacuation of haematoma acted to significantly reduce ICP and improve CPP. Given that these factors seem to be related to deterioration, death and early outcome, it would seem that surgery could play a role in reducing mortality and improving outcome following Intra cerebral Haemorrhage (ICH).

Blood Pressure↗
PubMed2000

Magnetic resonance imaging of the facial nerve in children with idiopathic facial paralysis.

The role of gadolinium-enhanced MRI (Gd-MRI) in the diagnosis of idiopathic facial paralysis (IFP) in children is not well defined. Fourteen children with IFP were evaluated to assess the use of Gd-MRI for the presence and pattern of enhancement and its usefulness in predicting the recovery of facial function. Six of 14 children had enhancement of the facial nerve on Gd-MRI, whereas 8 had none. Enhancement was noted in the tympanic, mastoid, and most commonly in the distal intracanalicular and labyrinthine segments. The average time from onset of paresis to recovery in patients with enhancement was 19.3 weeks, whereas in those with no enhancement, mean recovery time was 9.5 weeks (P = 0.003, t test). All 14 patients eventually had recovery to House-Brackmann grade I or II. Gd-MRI is not required for all children with IFP but may yield information about the time course of recovery of facial function.

Adolescent↗
PubMed2000

Surgery in intracerebral hemorrhage. The uncertainty continues.

BACKGROUND AND PURPOSE: Primary intracerebral hemorrhage (ICH) accounts for 10% to 20% of stroke but carries the highest rates of mortality and morbidity of all stroke subtypes. Current treatment, however, is varied and haphazard. The most recent Cochrane systematic review refers to 4 prospective, randomized controlled trials. We present a further meta-analysis to include 3 new trials. In addition, we review the trials of Chen et al and McKissock et al and discuss aspects of their quality that, we believe, prevent their inclusion in modern day meta-analysis. METHODS: Literature databases and articles were searched from 1966 to October 1999. Using the end points of death and dependency, the results of the 7 identified randomized trials were expressed as odds ratios. All available data were then analyzed with meta-analysis techniques. Analysis of relevant subsets of trials was also carried out. RESULTS: Meta-analysis of all 7 trials shows a trend toward a higher chance of death and dependency after surgery (OR 1.20; 95% CI 0.83 to 1.74). Meta-analysis was also carried out after exclusion of the Chen and McKissock trials for reasons discussed in the text. This meta-analysis suggests a benefit from surgery, with a reduction in the chances of death and dependency after surgical treatment by a factor of 0.63 (OR 0.63; 95% CI 0.35 to 1.14). CONCLUSIONS: When meta-analysis is restricted to modern-day, post-CT, well-constructed, balanced trials, a trend for surgery to reduce the chances of death and dependency is found. Perhaps, then, in the modern era of CT, good neuroanesthesia, intensive care, and the operating microscope, surgery has a role in the treatment of supratentorial intracerebral hemorrhage. The results of a large, multicenter, randomized controlled trial are urgently needed, and the ongoing International Surgical Trial of Intracerebral Hemorrhage should fulfill this objective.

Cerebral Hemorrhage↗
PubMed2000

Subperiosteal release of the floor of the mouth musculature in two cases of Pierre Robin sequence.

Many management approaches have been considered to relieve upper respiratory obstruction in patients with Pierre Robin sequence, but the choice of treatment is determined by the severity of the obstruction. These options include prone positioning, the use of a nasal trumpet, and surgery. One surgical technique is the subperiosteal release of the floor of the mouth musculature. The theory behind this procedure is that this musculature is under tension, and therefore it pushes the tongue upward and backward, resulting in respiratory obstruction. In theory, the release of this musculature from the mandible should alleviate the tension and hence clear the obstruction. In an attempt to objectively evaluate this theory, we performed subperiosteal release surgery on two infants. Our first patient required an emergent tracheostomy on postoperative day 2 because of the onset of surgically induced airway edema. To avoid this complication in the second patient, we performed a tracheostomy at the same time as surgery. Pre- and postoperative magnetic resonance imaging in the second patient revealed only a minimal change in the anatomy of the floor of the mouth musculature. We believe the subperiosteal release of the floor of the mouth musculature requires further evaluation before it can be considered to be effective in the surgical treatment of respiratory obstruction in Pierre Robin sequence.

Airway Obstruction↗
PubMed1999

Primary eyelid mucinous adenocarcinoma of eccrine origin.

To report a case of mucinous adenocarcinoma of the eyelid. A 70-year-old man presented with a lesion of his lower left eyelid, which had been growing over the past few years. An excisional biopsy was performed. The lesion was incompletely excised and recurrence at the excision site was observed at a 3-month follow-up visit. A histopathological examination of the excised specimen showed it to be a mucinous adenocarcinoma of eccrine origin. Primary mucinous adenocarcinoma of the eye lid is a rare malignant sweat gland tumor with a high incidence of local recurrence. It has to be differentiated from other adenocarcinomas which may rarely metastasize to the skin.

Adenocarcinoma, Mucinous↗
PubMed1998

Polymeric chitosan-based vesicles for drug delivery.

A simple carbohydrate polymer glycol chitosan (degree of polymerization 800 approx.) has been investigated for its ability to form polymeric vesicle drug carriers. The attachment of hydrophobic groups to glycol chitosan should yield an amphiphilic polymer capable of self-assembly into vesicles. Chitosan is used because the membrane-penetration enhancement of chitosan polymers offers the possibility of fabricating a drug delivery system suitable for the oral and intranasal administration of gut-labile molecules. Glycol chitosan modified by attachment of a strategic number of fatty acid pendant groups (11-16 mol%) assembles into unilamellar polymeric vesicles in the presence of cholesterol. These polymeric vesicles are found to be biocompatible and haemocompatible and capable of entrapping water-soluble drugs. By use of an ammonium sulphate gradient bleomycin (MW 1400), for example, can be efficiently loaded on to these polymeric vesicles to yield a bleomycin-to-polymer ratio of 0.5 units mg(-1). Previously polymers were thought to assemble into vesicles only if the polymer backbone was separated from the membrane-forming amphiphile by a hydrophilic side-arm spacer. The hydrophilic spacer was thought to be necessary to decouple the random motion of the polymer backbone from the ordered amphiphiles that make up the vesicle membrane. However, stable polymeric vesicles for use in drug delivery have been prepared from a modified carbohydrate polymer, palmitoyl glycol chitosan, without this specific architecture. These polymeric vesicles efficiently entrap water-soluble drugs.

Biocompatible Materials↗
PubMed1991

Coding of temporal parameters of complex sounds by frog auditory nerve fibers.

1. Physiological recordings were made from single auditory fibers in the frog eighth nerve to determine quantitatively how the different behaviorally relevant temporal parameters (the signal rise-fall time, duration, and rate of amplitude modulation) of complex sounds are encoded in the auditory periphery. Individual temporal parameters were varied. Response functions (RFs) were constructed with respect to each of these parameters using each unit's best excitatory frequency (BF) as the carrier. 2. In response to a change in signal rise-fall time, auditory nerve fibers showed little change in the mean spike count or firing rate, i.e., all fibers displayed ALL-PASS RFrfts. But the transient components, particularly the early phasic component, of responses varied with rise-fall times; these components were more pronounced in the responses to stimuli with shorter rise-fall times. 3. In response to an increase in signal duration, auditory nerve fibers showed a corresponding increase in firing duration and thus in the mean spike count, giving rise to HIGH-PASS RFdurs. The shape of response curves differed among fibers; the difference appeared to be related to the fiber's temporal adaptation characteristic. When the firing rate was measured, all fibers displayed higher mean firing rates in response to shorter duration stimuli than they did to longer duration stimuli, thus giving rise to LOW-PASS response functions. 4. To determine the response transfer functions to modulation rate, pulsed (PAM) and sinusoidally (SAM) amplitude-modulated signals were used. These signals differed substantially in terms of their envelopes and how they varied with AM rate. Data were analyzed by 1) plotting spike counts against the AM rate to derive modulation transfer functions (MTFspks) and 2) plotting synchronization coefficients (SCs) against the AM rate to generate MTFscs. 5. In response to PAM stimuli, all fibers showed an increase in mean spike count with modulation frequency over the range examined, giving rise to HIGH-PASS MTFspks. 6. For SAM stimuli, the average energy and duty cycle are independent of AM rate. Most (79%) auditory fibers showed little selectivity for AM rate over a range of 5-400 Hz, giving rise to ALL-PASS MTFspks. The remaining auditory fibers displayed LOW-PASS MTFspks, i.e., there was a distinct decline in the mean spike count with increasing AM rate. 7. In response to PAM stimuli, most fibers showed good response synchrony at low AM rates but the SC declined with an increase in the AM rate (i.e., LOW-PASS MTFscs). The cut-off frequency was typically very high, averaging 90 pulses/s.(ABSTRACT TRUNCATED AT 400 WORDS)

Acoustic Stimulation↗