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Biomedical subjects

G Malik

Publications and source records attributed to G Malik.

At least 19 recordsLinked to original sources
PubMed2006

Is the "instant flow" option on the NIOX analyser needed?

Asthmatics have increased gaseous nitric oxide in their exhaled breath. Measurements of the fraction of nitric oxide in exhaled breath (FE(NO)) are used for the diagnosis and management of asthma. One analyser (the NIOX chemiluminescence analyser) has a feature (restriction of instant flow, IF) which we suspected was responsible for reducing the success rate for obtaining FE(NO) measurements whilst not affecting the measurement itself. In a study involving 38 children, median age 10 years, we observed that FE(NO) values taken in the same individual with and without IF restriction did not differ. We also observed that the success in obtaining a FE(NO) measurement was higher (57%) when IF was not restricted and was lower (41%) when IF was restricted, p=0.002. Our findings do not support the use of restriction of IF on the NIOX analyser.

Adolescent↗
PubMed2005

Immunogenicity of major cell surface protein(s) of Brucella melitensis Rev 1.

Brucella melitensis Rev 1 organisms were salt-extracted and the cell surface proteins (BCSPs) were found to be mainly 39-42 kDa (group 2 porin proteins) in addition to 31.6, 32.5, 58.5 and 14.7 kDa proteins. DEAE-Sephadex anion-exchange column chromatography of BCSPs yielded fraction 1, which contained one major protein (39.8-42.0 kDa) and a minor protein (31.6 kDa). All these proteins were found to be immunogenic by Western blotting. Fraction 1 along with monophosphoryl lipid A and trehalose dicorynomycolate adjuvants as well as BCSPs alone induced significant (p < or = 0.05) protection in BALB/c mice. Both these immunizing agents produced almost equivalent protection to live B. melitensis Rev 1 vaccine at 15 and 30 days post challenge. Lymphocyte stimulation test as well as delayed-type hypersensitivity reaction revealed that both these preparations induced cell-mediated immune response. These preparations also induced humoral immune response as indicated by indirect ELISA. Neither of the immune responses was significantly less (p < or = 0.05) than that with live B. melitensis Rev 1 vaccine, except that their duration was short.

Animals↗
PubMed1999

Role of interferon-alpha in the treatment of primary glomerulonephritis.

Interferon-alpha (IFN-alpha) is a naturally occurring cytokine. It was the first cytokine used with clinical benefit in the treatment of viral hepatitis and malignancies. Patients with viral hepatitis B or C may have complications with glomerulonephritis (GN). Improvement in proteinuria with or without clearing of viral markers after IFN-alpha therapy has been reported. This encouraged us to offer IFN-alpha therapy to four patients with GN. These patients refused treatment with steroids and/or cyclophosphamide because of concerns about side effects. One patient with membranous GN and two patients with mesangial GN (MesGN) had a remission of nephrotic syndrome. In one patient with type II diabetes and MesGN, renal insufficiency and proteinuria did not subside; however, renal function remained stable. The mechanism of action of IFN-alpha is discussed, with its possible role in the treatment of primary GN.

Adult↗
PubMed1998

Expression of transforming growth factor-beta complex in arteriovenous malformations.

The factors responsible for the development of cerebral arteriovenous malformations (AVMs) are not well known. Patients with hereditary hemorrhagic telangiectasia (HHT) have cutaneous vascular dysplasia and a high propensity to develop systemic and cerebral AVMs. Transforming growth factor-beta (TGF-beta) complex has been implicated in HHT. The aim of this study was to evaluate the expression of TGF-beta 1, TGF-beta 2, TGF-beta 3, and their two receptors (R1 and R2) in AVMs and in normal brain vessels. Formalin-fixed, paraffin-embedded tissues from 20 patients with cerebral AVMs (including two patients with HHT) were sequentially sectioned into 6 microns sections. Similar sections from normal brain tissue were obtained from five patients without AVMs and no intracranial pathology, who had died from unrelated causes. The normal tissue sections included large intracranial arteries, small arteries, venous sinuses, cortical veins, and brain tissue containing arterioles, capillaries, and venules. All specimens underwent immunohistochemical analyses with polyclonal antibodies to the following antigens: TGF-beta 1, TGF-beta 2, TGF-beta 3, and R1 and R2. The immunoreactivity, when present, was consistently noted in endothelial cells and in the medial smooth muscle. The intensity of vessel wall immunostaining was graded on a scale from 0 to 3. The mean staining grades of normal vessels for TGF-beta 1, TGF-beta 2, TGF-beta 3, R1, and R2 were 0.6 (range 0-1), 3, 2.8 (range 2-3), 1.6 (range 0-2), and 3, respectively, whereas the mean staining grades of AVM vessels were 0.3 (range 0-1), 0.8 (range 0-1), 0.6 (range 0-1), 1.4 (range 0-2), and 0.9 (range 0-1), respectively. The study thus demonstrated that normal brain vessels (arteries, veins, small vessels) have strong (range 2.8-3) immunostaining for TGF-beta 2, TGF-beta 3, and R2, and that the AVM nidus vessels have a paucity (range 0.8-0.9) of staining for these factors. In AVM vessels that had zero immunoreactivity to the above three factors, the vessel wall was fibrocollagenous rather than muscular. Further studies to examine the TGF-beta complex behavior in AVMs are needed.

Antibodies↗
PubMed1995

Presurgical localization of functional cortex using magnetic source imaging.

The boundaries of somatosensory cortex were localized noninvasively by means of a large-array biomagnetometer in six patients with mass lesions in or near eloquent cortex. The results were used by neurosurgeons and neurologists in preoperative planning and for reference in the operating room. The magnetic source imaging (MSI) localizations from somatosensory evoked potentials were used to predict the pattern of phase reversals measurable intraoperatively on the cortical surface, providing a quantitative comparison between the two measures. The magnetic localizations were found to be predictive in all six cases, with the two sets of localizations falling within an 8-mm distance on average. Somatosensory localizations using MSI offer accuracy in localizing somatosensory cortex stereotactically and in depicting its relationship to lesions. Such data are valuable preoperatively in assessing the risks associated with a proposed surgical procedure and for optimizing subsequent minimum-risk surgical strategy.

Adult↗
PubMed1992

Stereotactic endoscopic interventions in cystic and intraventricular brain lesions.

Image guided stereotaxis is an accurate and safe method of directing therapy to target volumes defined in two-dimensional (2D) multiplanes or three-dimensional (3D) perspectives using computer reconstruction of image data. The major limitations of stereotactic techniques are related to a lack of intraoperative visualization and direct monitoring of the procedures and to changes of intracranial coordinates after decompression of cystic lesions or aspiration of cerebrospinal fluid in the management of intraventricular lesions. Endoscopic laser stereotaxis (ELS) involves integration of rigid-flexible endoscopy and Nd-YAG laser to 3D-2D multiplanar image-guided stereotactic procedures. The major advantages of ELS include: direct intraoperative visualization, hemostasis, evacuation or resection assessment, and wide exploration of intracranial cavities or ventricles. The technique allows safe aspiration, biopsy, and resection or internal decompression of deep and subcortical intracranial lesions. ELS has proved to be safe and effective in the management of 76 clinical cases and appears to be a promising technique in the management of cystic and intraventricular lesions.

Brain Diseases↗
PubMed1991

Application of multimodality imaging stereotactic localization in the surgical management of vascular lesions.

Multidimensional image preplanning and accurate pre and intraoperative localization for intracranial vascular lesions have been implemented. Methodology include carbon fiber base ring, localizer plates, any X-ray tubes, PC compatible software and intraoperative localizing unit. Surgical management of deep arteriovenous malformations is especially suitable for this technique, including the use of intraoperative digital angiography.

Cerebrovascular Disorders↗
PubMed1991

Sister chromatid exchange analysis in monitoring chlorambucil therapy in primary nephrotic syndrome of childhood.

Sister chromatid exchange (SCE) analysis is the most sensitive method for assessing chromosome damage induced by chemical mutagens. We report the SCE of peripheral blood lymphocytes in children with primary nephrotic syndrome (NS) treated with chlorambucil. Group I consisted of 20 normal children, group 2 of 14 children with primary NS who had never received a cytotoxic drug and group III of 7 children with primary NS who had received chlorambucil, which was discontinued 6-36 months prior to the study. Group IV consisted of 4 nephrotic children who were receiving chlorambucil therapy during the study. There was no significant increase in SCE in group III compared with group I or group II (P much greater than 0.05). A significant rise in SCE (P less than 0.05) was seen in all patients in group IV.

Child↗
PubMed1990

Image-guided stereotactic centered craniotomy and laser resection of solid intracranial lesions.

A technique in which solid intracranial lesions are removed using computerized image processing under stereotactic conditions is described. A specially developed carbon fiber ring holder compatible with most image studies is used as a reference system. Intraoperatively it affords freedom of patient positioning and unobstructed access to any site of the head. Four position alternatives of the aiming device allow the removal of lesions from any location. For superficial lesions located near eloquent areas, a 'centered' craniotomy is performed, usually under local anesthesia, and removal is performed using loupe magnification, bipolar coagulation ultrasonic aspiration of the Nd:YAG laser fiber in the contact or noncontact technique. In deep-seated lesions, a surgical 'corridor' is established and kept by means of retractors adapted for use with the stereotactic apparatus. Microsurgical techniques and the CO2 laser are used in solid lesions; in vascular lesions, bipolar coagulation or the ND:YAG laser can be used. Centered craniotomy allows the precise localization, enhancement, three-dimensional orientation and removal of lesions with minimal trauma to the surrounding brain. The technique has been applied in 78 cases where the extreme accuracy of the technique, benign postoperative course and short hospitalization have been impressive.

Angiography, Digital Subtraction↗
PubMed1989

Tumour recurrence vs radionecrosis: an indication for multitrajectory serial stereotactic biopsies.

External RT has been proved to be an important adjuvant to surgery in the treatment of malignant glioma. It has also been demonstrated, that its effect on survival is dose-dependent, although accompanied by a higher morbidity. Intents to localize the field of high dose RT to the tumour area have been performed with the aim to spare damage of the normal brain tissue. Between August 1983 to December 1987, 40 patients with malignant astrocytoma (16 GM, 24 AA) underwent high dose localized hyperfractionated external RT after surgical resection. Patients received 57.6 Gy to the tumour and oedema area associated with a boost localized to the tumour of 7.4, 14.4 or 24 Gy. In the follow-up, 16 patients died with evidence of increase in size of lesion diagnosed by CT/MRI. Since July 1987, 12 patients with recurrence or increase on size of CT/MRI lesion have undergone multitrajectory serial stereotactic biopsies. From the biopsies 8 patients were histologically diagnosed was compatible with radionecrosis. From the 4 recurrences, 2 patients were treated with 125I implants and 1 with new resection. Patients with radionecrosis were treated with corticoides and diuretics, obtaining partial or complete remission of symptoms and decrease in size of CT lesion. Undoubtly, Multiplanar/3D multitrajectory serial stereotactic biopsies play a major role in the follow-up of these patients, and accurate diagnosis need to be established for further treatment therapy. The question remains if these localized boost should be replaced by 3D Multiplanar stereotactic interstitial radiotherapy boost after surgery and conventional radiotherapy.

Astrocytoma↗
PubMed1987

Geriatric neurosurgery.

The "elderly," aged 65 and over, represent a rapidly growing proportion of the American population. Their percentage among the neurosurgical admissions at Henry Ford Hospital increased from 14.4% in 1978 to 22.4% in 1984. Occlusive cerebrovascular disease was the most frequent pathology seen, representing 40% of the population studied. Spinal degenerative myeloradiculopathy represented 14%, tumors 7%, trauma 5.4%, and intracranial hematomas represented 4% of the population. Vascular anomalies represented 3.3% of the patient group, with almost the same number of patients presenting with intracranial hemorrhage. The percentage of patients who were surgically treated was 58%. Mortality was 6.5%, with only 2.5% of the patients requiring special-care-facility placement following release from the hospital. An older group, aged 85 and over, represented 4% of our geriatric population. In the age 85+ group, occlusive cerebrovascular disease was the leading pathology (18% of the population), followed by subdural hematomas (15%), spinal degenerative myeloradiculopathy (11.6%), trigeminal neuralgias (7%), hydrocephalus (4%), vascular anomalies (4%), and tumors (4%). Patients in the age 85+ group were surgically treated in 41% of the cases, with a mortality of less than 10%. In the past, older age (greater than 65 years) was believed to be a contraindication to surgery, however, the increased life expectancy, number, and health of this population made reconsideration of this arbitrary age limit essential. We feel that age alone is not a barrier to proper neurosurgical treatment when other risk factors are adequately managed.

Age Factors↗
PubMed1987

Multiplanar CT-guided stereotaxis and 125I interstitial radiotherapy. Image-guided tumor volume assessment, planning, dosimetric calculations, stereotactic biopsy and implantation of removable catheters.

A method using Multiplanar CT-guided stereotactic biopsy and high-dose 125I interstitial radiotherapy in patients with malignant nonresectable or recurrent brain tumors is presented. Optimal interstitial radiotherapy requires careful preoperative planning, computer-assisted dosimetry, CT-guided stereotactic biopsy and implantation of catheters that will be loaded with 125I seeds. A method is presented by which the isodose curve distribution is adjusted to the tumor size, volume and axis, allowing treatment of the imaged and histologically determined border of the tumor with 60 Gy at a dose rate of 40 rad/h.

Biopsy↗
PubMed1986

Surgical approach to lung cancer with solitary cerebral metastasis: twenty-five years' experience.

From 1960 to 1985, 41 patients underwent resection of a lung cancer and one or more brain metastases. There were 24 men and 17 women ranging in age from 40 to 71 years (average, 56 years). Cell type was adenocarcinoma in 19 patients, squamous in 16, small cell in 4, and large cell in 2. Wedge resection was performed in 4 patients, lobectomy in 20, pneumonectomy in 14, and bilobectomy in 3. Brain irradiation was used for 25 patients (61%). To date, the longest survival is 18.3 years after craniotomy; mean survival is 2.3 years +/- 3.8 (+/- standard deviation). Survival was 55 +/- 7.9% (+/- standard error) at 1 year, 31 +/- 7.4% at 2 years, 21 +/- 6.5% at 5 years, and 15 +/- 6.0% at 10 years. Using multivariate analysis, we evaluated possible significant predictors of improved survival. Only wedge resection was a significant predictor (p less than .01), which suggests better results with a small peripheral lung tumor. Results of our 25 years' experience using an aggressive approach to lung cancer with solitary cerebral metastasis indicate significantly improved patient survival that justifies its widespread use.

Adult↗
PubMed1986

Cranial invasion by basal cell carcinoma.

The direct spread of basal cell carcinoma (BCC) into the bones of the cranium takes a long period. In its early stages, it may not be detectable by radiography or computerized tomography, but can be visible as pitting during surgery. Invasion through the thickness of the calvarium due to extension of a BCC of the scalp, or involvement of the cribriform plate by spread from an intranasal lesion, is serious. Examples of cranial invasion by BCC are presented. The methods used in diagnosis and treatment are outlined.

Aged↗
PubMed1986

Fusariotoxicoses of farm animals and mycotoxic leucoencephalomalacia of the equine associated with the finding of trichothecenes in feedstuffs.

Mycotoxicoses involving horses, rabbits and cattle have been studied. Fusarium tricinctum and T-2 toxin were isolated from all incriminated feedstuffs. Other isolated trichothecenes from the feed included HT-2, verrucarins and roridin. The toxins were separated, identified and quantitated using thin-layer chromatography, gas-liquid chromatography and mass spectrometry. T-2 toxin was detected in amounts varying from 0.5-204 ppm. The contaminated feedstuffs in connection with the affected horses and rabbits, included cereal grains (corn, cornstalks, bran and barley), whereas fescue hay was associated with the mucocutaneous findings in the bovine episode. The effects of the toxin(s) seemed to be host specific and varied according to the different animal species. Horses and rabbits developed primarily central nervous disorders with conspicuous pathological findings in the brain. Hepatitis and nephritis were also seen in naturally intoxicated horses and experimentally fed rats. Affected cattle developed mucocutaneous eruptions around the mouth and nostrils. In addition, dermonecrotic findings were observed involving the extremities, ear and tail. Fusariotoxicoses are toxic conditions of farm animals and man caused by the ingestion of cereal grains and forages contaminated by different fungal species of the genus Fusarium. A variety of clinical and pathological findings have been reported (5,6,10,13,15,17,31). This study concerns neuropathic findings in horses and rabbits and mucocutaneous lesions in cattle in association with T-2 toxin contamination.

Animal Diseases↗