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T Khan

Publications and source records attributed to T Khan.

80 records · Page 5Linked to original sources
PubMedDate not supplied

The influence of synthetic conditions on the stability of methotrexate-monoclonal antibody conjugates determined by reversed phase high performance liquid chromatography.

Methotrexate (MTX) has been convalently attached to an IgG-type monoclonal antibody (791T/36) directed to tumour-associated antigen gp72. Conjugates were synthesized by the active ester method using MTX N-succinimidyl ester at various pH values (7.5-10.5). Following purification by gel filtration, high performance liquid chromatography was used to assess the free drug or its derivatives in samples of MTX-791T/36 conjugates previously treated (or not) with hydroxylamine. Quantitative analysis, performed on a reversed phase column (pore size 300 A) with isocratic acetonitrile-sodium acetate buffer (pH 4.8) as mobile phase, indicated no detectable amount of free methotrexate in hydroxylamine-treated conjugates even six months after their preparation. Similar observations were made with conjugates, whose synthesis were performed at pH greater than or equal to 10. In contrast, the presence of increasing amounts of drug/metabolite could be demonstrated in samples produced at lower pH values. Based on these findings, the pH-dependent kinetics of MTX release has been determined and used to design conditions under which stable MTX-791T/36 conjugates could be prepared without hydroxylamine reaction.

Antibodies, Monoclonal↗
PubMedDate not supplied

Clinical study of Multiload Cu375 in Pakistan.

Three hundred and sixty five volunteers were observed for a total of 4882 woman-months for the clinical evaluation of MLCu375. Data were analyzed by life-table method at 6, 12 and 18 months. Most women were 21-30 years old, and of parity 2-4. Continuation rates of 78.2 and 68.8 at 12 and 18 months, respectively, and a pregnancy rate of 0.3% proved the device to be highly effective and well tolerated.

Adolescent↗
PubMedDate not supplied

Acetyl-L-carnitine effects on nerve conduction and glycemic regulation in experimental diabetes.

UNLABELLED: Acetyl-L-Carnitine (ALC), an activator of carnitine, can accelerate nerve regeneration after experimental surgical injury in rats. In this study, we examined the ability of ALC to improve nerve conduction velocity and its effect on intravenous glucose tolerance test in streptozotocin-induced diabetic rats. Diabetic (blood glucose > 200 mg%) and normal animals were treated intraperitoneally for four weeks with ALC, 50 mg/Kg/d and 150 mg/Kg/d. Nerve conduction velocity was measured by direct exposure of sural nerve. Two-hour IVGTT was studied by measuring plasma glucose, insulin and free fatty acids after intravenous injection of glucose, 1.75 gm/Kg/body weight in animals treated either with ALC 150 md/Kg/d or saline alone. Six weeks of STZ-induced diabetes resulted in impairment of nerve conduction velocity in animals injected with saline (16.05 +/- 1.09 m/s), as compared to saline-treated normals who did not receive streptozotocin (31.0 +/- 0.84 m/s, p<0.0005). Diabetic animals treated with ALC, 150 mg/Kg/d, preserved near normal nerve conduction (27.10 +/- 1.42 m/s), compared with the saline-treated diabetic animals (p < 0.0005), but diabetic animals treated with ALC, 50 mg/Kg/d, had a non-significant increase in nerve conduction (23.68 +/- 1.6). ALC treatment had no effect on fasting or post-intravenous plasma glucose in normal or diabetic rats, although it moderately reduced baseline and 40 minute insulin levels (p < 0.02) in normal rats as compared with their saline-treated counterparts. ALC treatment lowered baseline free fatty acids in normal (p < 0.04) and diabetic (p < 0.03) animals, and the 60 minute levels in the normal group only (p < 0.003). CONCLUSION: ALC at a dose of 150 mg/Kg/d given for one month, produced near normalization of nerve conduction velocity in streptozotocin-induced diabetes with no adverse effects on glucose, insulin or free fatty acid levels.

Acetylcarnitine↗
PubMedDate not supplied

Infectious complications associated with ventricular assist systems.

Infectious complications during support with a ventricular assist system (VAS) can cause severe morbidity and mortality, affecting nearly one-half of all VAS recipients. Because of the lack of a uniform definition of infection, the incidence of this complication is hard to determine accurately. It is approximately 50% for patients being supported by an implantable VAS as a bridge to heart transplantation and 28% for patients supported by an external, short-term VAS. Infections can be classified according to the involvement or noninvolvement of the implanted device and according to the severity of the infection. Severe infections involving the implanted device may preclude heart transplantation for some patients, but numerous patients with milder infections have undergone successful transplantation. Numerous factors predispose VAS patients to infection. Postoperative bleeding necessitating re-operation is an important contributing factor. Endotracheal tubes, intravascular catheters, and other indwelling tubes necessary for the care of postsurgical patients are also common routes of contamination. Control of infection may be improved with new VAS designs, antibiotic impregnated drivelines, and innovative therapies such as antibiotic beads. The next generation of VASs should be inherently less susceptible to infection because of their smaller size, reduced thrombogenicity, and better flow characteristics. In addition to more effective antibiotics, improved VAS designs that incorporate transcutaneous energy transmission systems may reduce infectious complications and allow safe, long-term VAS support.

Equipment Design↗
PubMedDate not supplied

Mechanical, bioadhesive strength and biological evaluations of chitosan films for wound dressing.

PURPOSE: To investigate the suitability of chitosan films prepared using two different solvents, acetic acid (Chitosan-AA) and lactic acid (Chitosan-LA), for wound dressing, in comparison with a commercial preparation, Omiderm. METHODS: The mechanical and in-vitro bioadhesive strength properties of Chitosan-AA, Chitosan-LA, and Omiderm were investigated using texture analyzer equipment. The vapour permeability of chitosan films was determined using a method for evaluation of moisture permeability of containers and packaging material described in USP XXII. In addition, the biological evaluations were performed via primary skin irritation, intracutaneous, and systemic injection tests. RESULTS: The three preparations differed significantly in terms of the mechanical and bioadhesive strength properties. Chitosan-LA exhibited a lower tensile strength, but more flexible and bioadhesive than Chitosan-AA. Chitosan film was found to be permeable to water vapour. Chitosan-LA and Omiderm were non-irritant and did not cause any skin allergic reaction. In contrast, Chitosan-AA films inflicted adverse skin reactions. Nevertheless, no gross sign of toxicity was encountered from the systemic injection of the extracts of the three preparations. CONCLUSION: Chitosan films demonstrated significantly different mechanical and bioadhesive strength properties from Omiderm. Chitosan-LA was more soft, flexible, pliable and bioadhesive when compared to Chitosan-AA films. Furthermore, Chitosan-LA did not cause erythema, edema and systemic toxicity. Hence, Chitosan-LA film is suitable to be used in the management of wound healing and skin burn.

Acetylation↗