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Biomedical subjects

Neeraj Kumar

Publications and source records attributed to Neeraj Kumar.

49 records · Page 3Linked to original sources
PubMed2004

Myeloneuropathy and anemia due to copper malabsorption.

Dietary deficiency of copper results in a progressive ataxic myelopathy in ruminants called swayback. Menkes disease is a human disease due to an inherited defect in copper absorption; survival into adulthood is typically not known to occur. We report a 63-year-old woman who was evaluated by us for a myeloneuropathy that occurred in the setting of copper malabsorption. Her neurological deterioration stopped with copper supplementation. The limited literature on neurological manifestations of acquired copper deficiency suggests that the clinical presentation resembles the myeloneuropathy seen with vitamin B12 deficiency.

Anemia↗
PubMed2004

Acquired hypocupremia after gastric surgery.

BACKGROUND & AIMS: Copper absorption in humans probably occurs in the stomach and duodenum. Copper is essential for the structure and function of the nervous system and acquired copper deficiency in humans has been recognized to cause a myelopathy that resembles vitamin B12 deficiency. Acquired copper deficiency is not a well-recognized complication of gastric surgery. In Menke's disease a defect in enterocyte transport of absorbed copper results in increased copper content in the duodenal mucosa and hypocupremia. METHODS: We report 2 patients who developed neurologic deficits with copper deficiency many years after gastric surgery. In 2 other patients with hypocupremic myelopathy but no history of gastric surgery, colonic copper was measured to determine if an absorptive defect similar to that seen in Menke's disease may be responsible for hypocupremia. RESULTS: In all 4 patients copper deficiency was identified as the cause of the myelopathy. In 2 patients the copper deficiency occurred after gastric surgery. Eight additional patients with copper deficiency after gastric surgery were identified from the literature. Six of these 8 patients also had neurologic manifestations. Colonic mucosa copper content was increased in the 2 patients with hypocupremia without prior gastric surgery. CONCLUSIONS: Acquired copper deficiency may be a delayed complication of gastric surgery and may result in a myelopathy similar to that seen with vitamin B12 deficiency. In some patients with acquired copper deficiency no cause for the hypocupremia may be evident and a primary absorptive defect should be considered.

Aged↗
PubMed2004

Dose comparison of tranexamic acid in pediatric cardiac surgery.

To compare different doses of tranexamic acid, 150 consecutive children with congenital cyanotic heart disease were randomly assigned to one of 5 groups of 30 each. Group A served as a control. Group B received 50 mg.kg(-1) of tranexamic acid at induction of anesthesia. Group C received 10 mg.kg(-1) at induction followed by an infusion of 1 mg.kg(-1).h(-1). Group D had 10 mg.kg(-1) at induction, 10 mg.kg(-1) on bypass, and 10 mg.kg(-1) after protamine. Group E had 20 mg.kg(-1) at induction and again after protamine. The control group had the longest sternal closure time, the greatest blood loss in the first 24 hours, and the highest requirements for blood and blood products. Among the 4 groups given tranexamic acid, group D (triple dose) had the best results, followed by group E (double dose). Group B (single dose) had the worst results among the groups receiving tranexamic acid.

Adolescent↗
PubMed2004

Scleromyxedema in a patient with multiple sclerosis and monoclonal gammopathy on interferon beta-1a.

BACKGROUND: Animal studies have shown that some human monoclonal antibodies promote myelin repair in models of demyelinating disease. Scleromyxedema is a dermatologic disorder associated with a monoclonal gammopathy and neurologic manifestations. The reason for occurrence of cutaneous reactions in interferon treated patients is unknown. CASE DESCRIPTION: A 37-year-old woman was started on weekly interferon beta-1a (IFN beta-1a) following a diagnosis of multiple sclerosis (MS). After having been on interferon therapy for three years, she developed skin lesions secondary to scleromyxedema. Her IFN beta-1a was discontinued and intravenous immunoglobulin therapy was started for her scleromyxedema. At a six-month follow up, her skin lesions improved and there was no recurrence of neurologic symptoms. CONCLUSIONS: This is the first report of occurrence of scleromyxedema in a patient with MS. While this could be a chance association, it does raise the question if her neurologic manifestations could be secondary to scleromyxedema. Further research into the mechanism of IFN related cutaneous side effects is needed. Evidence regarding the remyelinating nature of human monoclonal antibodies raises interest in the potential therapeutic role these antibodies may have.

Adjuvants, Immunologic↗
PubMed2004

Paramedian lumbar epidural catheter insertion with patients in the sitting position is equally successful in the flexed and unflexed spine.

Positioning for placement of an epidural catheter can be quite painful for patients with lower limb injuries. We randomly allocated 50 patients scheduled for surgery after lower limb injuries for placement of a lumbar epidural catheter in the sitting position with the back in the neutral unflexed position by either the midline or paramedian approach. If the approach failed after two attempts, patients were placed in a flexed-spine position, and the procedure was attempted again. Technical difficulties and complications were recorded. In 17 patients in the midline group, and 1 patient in the paramedian group, it was not possible to insert the needle initially, and a flexed-spine position was required (P < 0.05). The incidences of resistance to catheter insertion (eight versus one), paresthesia (seven versus zero), and appearance of blood in the catheter (six versus zero) were significantly more frequent in the midline compared with the paramedian approach. The midline group also experienced more discomfort than the paramedian group. We conclude that, with the patient sitting with an unflexed spine, it is usually possible to insert an epidural catheter with the paramedian approach.

Adult↗
PubMed2004

Dyspnea as the predominant manifestation of bilateral phrenic neuropathy.

Phrenic neuropathy associated with brachial neuritis has been well described; however, bilateral phrenic neuropathy with minimal or no involvement of the brachial plexus has not. We review the clinical features, as well as the results of radiographic studies, pulmonary function tests, and electrodiagnostic studies, of 3 patients in whom dyspnea was the presenting manifestation of bilateral phrenic neuropathy. All 3 patients had acute-onset dyspnea, which led to consideration of a pulmonary or cardiac etiology. Phrenic nerve conduction studies showed bilateral axonal degeneration of the phrenic nerves. Diaphragmatic paralysis should be considered in the differential diagnosis of acute-onset dyspnea. Dyspnea increases typically when the patient lies down, and paradoxical respiration may be present. Neck, shoulder, or upper limb pain may occur at onset. Inspiratory pressures may be reduced, but a comparison of the forced vital capacity when the patient is standing and supine is more specific for diaphragmatic weakness. Phrenic nerve conduction studies and diaphragmatic electromyography may provide evidence of bilateral involvement. Subclinical evidence of brachial plexus involvement may be present. The prognosis for patients with bilateral phrenic neuropathy may be more favorable than reported previously.

Brachial Plexus Neuritis↗
PubMed2004

Acquired cerebral hemiatrophy: idiopathic?

The authors report the case of a young man with acquired cerebral hemiatrophy that was progressive initially but stabilized after a few months. He did not have any seizure throughout the course of his illness. No definite cause was evident despite extensive investigations. He did have a slight increase in white cell count on a cerebrospinal fluid study done during the progressive phase of his illness suggesting that an unidentified infective or inflammatory illness may have resulted in the cerebral hemiatrophy. The authors suggest that Rassmusen's encephalitis may in fact be a spectrum with the typical descriptions representing one end. The importance of multimodality imaging in evaluating patients with cerebral hemiatrophy is discussed.

Adult↗
PubMed2003

Myelopathy due to copper deficiency following gastrointestinal surgery.

BACKGROUND: Ataxic myelopathy due to copper deficiency has been described in ruminant animals and is called swayback. Neurological manifestations due to inherited copper deficiency secondary to the failure of intestinal copper absorption is well recognized as Menkes disease. The neurological consequences of acquired copper deficiency in humans are not well described. OBJECTIVE: To report 2 cases where patients developed a myelopathy with copper deficiency after gastrointestinal surgery.Patients Two patients developed a myelopathy many years after gastrointestinal surgery. Both had severe copper deficiency, which was the likely cause of the myelopathy. CONCLUSIONS: Acquired copper deficiency may present as a myelopathy. Gastrointestinal surgery and resulting decreased copper absorption may be causative.

Absorption↗
PubMed2003

Anhydride prodrugs for nonsteroidal anti-inflammatory drugs.

PURPOSE: The objective of this study was to synthesize anhydride prodrugs for prolong action to shield the carboxylic acid group from irritative effects and to temporary hydrophobize the drug so that it becomes accessible to aqueous media when the anhydride residue is hydrolyzed. METHODS: Ibuprofen, a nonsteroidal anti-inflammatory agent, was used as a representative drug for anhydride derivatization. Mixed anhydrides of ibuprofen with fatty acids of different chain length were prepared by reacting acid chloride derivatives with the corresponding acid in the presence of acid acceptor and two-phase reaction. Mixed anhydrides were also prepared by dehydration reaction using acetic anhydride and anhydride interchange of symmetric anhydrides. The analgesic effects of mixed anhydride prodrugs were tested using nonsteroidal anti-inflammatory drug rat paw edema model. In vitro degradation of mixed anhydrides and drug release were monitored by high-performance liquid chromatography. RESULTS: Ibuprofen was bound to aliphatic and aromatic acids via an anhydride bond in high reaction yields (>85%) with high mixed anhydride content (>80%). The mix anhydride was purified by chromatography and stored at 4 degrees C to minimize conversion into the symmetric anhydride. These anhydride derivatives hydrolyzed at different time intervals depending on the hydrophobicity of conjugated acid. In vivo testing of the ibuprofen anhydride derivatives for analgesic effect indicated an extended action of the drug for over 24 h as a function of the fatty acid chain length. CONCLUSION: This study demonstrates the promise of anhydride prodrugs for extending drug action and shielding the carboxylic acid group.

Anhydrides↗
PubMed2002

Polyanhydrides: an overview.

Polyanhydrides have been considered to be useful biomaterials as carriers of drugs to various organs of the human body such as brain, bone, blood vessels, and eyes. They can be prepared easily from available, low cost resources and can be manipulated to meet desirable characteristics. Polyanhydrides are biocompatible and degrade in vivo into non-toxic diacid counterparts that are eliminated from the body as metabolites. Owing to their usefulness, this review focuses on the development, synthesis methods, structures and characterization of polyanhydrides, which will provide an overview for the researchers in the field. Their in vitro and in vivo degradability, toxicity, biocompatibility and applications are discussed in the subsequent chapters of this special issue on polyanhydrides and poly(ortho esters).

Anhydrides↗