Search PubMed⌕ Search

Biomedical subjects

A Patel

Publications and source records attributed to A Patel.

At least 487 records · Page 27Linked to original sources
PubMed1986

3-Methoxy-4-(2-nitrovinyl)phenyl glycosides as potential chromogenic substrates for the assay of glycosidases.

Selective glycosidation of 2,4-dihydroxybenzaldehyde with either 2,3,4, 6-tetra-O-acetyl-alpha-D-glucopyranosyl bromide, 2-acetamido-3,4,6-tri-O-acetyl-alpha-D-glucopyranosyl chloride, or 2,3,4,6-tetra-O-acetyl-alpha-D-galactopyranosyl bromide afforded the corresponding 4-O-glycosyl derivatives. Subsequent O-methylation, O-deacetylation, and condensation with nitromethane afforded the appropriate beta-glycoside of 3-methoxy-4-(2-nitrovinyl)phenol. The phenol is highly coloured at alkaline pH so that these glycosides may be suitable as chromogenic substrates for the assay of glycosidases.

Chemical Phenomena↗
PubMed1986

Endolaser treatment of the ciliary body for uncontrolled glaucoma.

We used vitrectomy and transvitreal endophotocoagulation of the ciliary processes to treat 18 eyes with severe glaucoma that could not be managed successfully by medical therapy and conventional glaucoma surgery. Lensectomy was performed in the two phakic eyes in the series because of cataractous lens changes. A pars plana vitrectomy was done in each eye and a fiberoptic probe used to apply transvitreal blue-green argon laser photocoagulation directly to the ciliary processes. Treatment of more than 180 degrees was necessary for sufficient lowering of the intraocular pressure. Postoperative intraocular pressure was equal to or less than 20 mmHg in 14 of 18 eyes, although nine of the 14 successful cases required postoperative medical therapy. Complications included transient vitreous hemorrhage (2 eyes), transient choroidal detachment (2 eyes), and hypotony (1 eye).

Adolescent↗
PubMed1986

Selective inhibition of proteolytic enzymes in an in vivo mouse model for experimental metastasis.

Peptide aldehyde transition state analogue inhibitors of serine and cysteine proteases have been used to selectively inhibit proteases for which prior evidence supports a role in tumor cell metastasis. These enzymes include cathepsin B, urokinase plasminogen activator (PA), and thrombin. The inhibition constants of the peptidyl aldehyde inhibitors show that they are highly selective for a particular targeted serine or cysteine protease. The inhibitors are introduced by i.p. injection or by miniosmotic pumps into syngeneic C57BL/6 mice also given injections of B16-F10 melanoma cells, and the number of metastatic foci in the lung was determined. While the injection protocol gave an initially high but changing in vivo concentration of inhibitor over time, the minipump implant gave a constant steady state concentration of inhibitor over 5-7 days. Minipump infusion of leupeptin (acetylleucylleucylargininal), a strong inhibitor of cathepsin B at a steady state plasma concentration 1000-fold greater than its Ki(cathepsin B), gave no significant decrease in lung colonization by the B16 tumor cells. Ep475, a stoichiometric irreversible peptide inhibitor of cathepsin B-like proteases, also did not significantly inhibit metastatic foci formation. Introduction of selective inhibitors of urokinase PA, tert-butyloxycarbonylglutamylglycyl-argininal and H-glutamylglycylargininal at concentrations near its Ki, produced no significant decrease in mouse lung colonization. The selective thrombin inhibitor D-phenylalanylprolylargininal infused to a steady state concentration 100-fold greater than its Ki dramatically increased B16 melanoma colonization of mouse lung. The results indicate that neither secreted cathepsin B-like nor urokinase PA have roles in B16 colonization of mouse lung, while thrombin may have a role in preventing metastasis. These experiments do not eliminate roles for a cathepsin B-like enzyme or urokinase PA in the initial steps of the metastatic process.

Animals↗
PubMed1986

[Treatment of recurrent anterior dislocations of the shoulder by the technic of pre-glenoid stapling. Study of a series of 48 cases].

Preservation of local muscular structures, and closure of the capsulo-periosteum detachment, are the two essential principles observed, when treating recurrent anterior shoulder dislocation by pre-glenoid stapling and also afford satisfactory results. This technique is used for capsulo-ligamentar lesions without alterations of the anterior edge of the glenoid cavity. If the strict technique is followed when placing the staple excellent stability result. If physiotherapy is started early, functional recovery is rapid. Sporting activities can be resumed within the third month after the operation.

Adult↗
PubMed1985

Serial ultrasound in amoebic liver abscess.

Serial ultrasound examinations were conducted in 93 patients with amoebic liver abscess. The initial size of the abscesses ranged from 3 to 17 cm. The time taken for complete healing to occur varied from 10 to 300 days and correlated directly with the initial size of the abscess cavity. As healing progressed, the abscess cavity became increasingly hypoechoic and assumed a smoother margin. In uncomplicated cases, complete healing occurred and, on ultrasound, no residual lesions were seen in the liver. There were two cases each of delayed healing and recurrence of amoebic liver abscess and the value of ultrasound in these situations is discussed. Ultrasound examination of the liver appears to be very suitable for assessing satisfactory progress of healing in amoebic liver abscess.

Humans↗
PubMed1985

Comparison of intracapsular and extracapsular cataract surgery. Histopathologic study of eyes obtained postmortem.

We examined 201 consecutive aphakic and pseudophakic eyes postmortem. Of these, 146 eyes had undergone intracapsular cataract extraction (ICCE) and 55 eyes had undergone extracapsular cataract extraction (ECCE), either with the posterior capsule preserved intact (ECCE-CI, 30 eyes) or having had a surgical discission performed (ECCE-D, 25 eyes). Wound-related complications were most numerous in the ICCE group, and this probably reflects the relatively recent development of microsurgical techniques. Posterior vitreous detachment was present in 84% of eyes following ICCE, in 76% of eyes following ECCE-D, and in 40% of eyes following ECCE-CI (P less than 0.001). Peripheral retinal holes were found in 8.2% of ICCE eyes, 8.0% after ECCE-D, and 3.3% of eyes after ECCE-CI. Five (3.4%) of ICCE eyes had associated retinal detachments, while no ECCE eyes had detachments. Macular edema, macular holes, and epiretinal membranes occurred in 2.1%, 1.4%, 12.3% of ICCE eyes; 4.0%, 0.0%, and 8.0% of ECCE-D eyes; and 0.0%, 6.7%, and 6.7% of ECCE-CI eyes, respectively.

Anterior Eye Segment↗
PubMed1985

Isolation of infectious human T-cell leukemia/lymphotropic virus type III (HTLV-III) from patients with acquired immunodeficiency syndrome (AIDS) or AIDS-related complex (ARC) and from healthy carriers: a study of risk groups and tissue sources.

Acquired immunodeficiency syndrome (AIDS) and AIDS-related complex (ARC) are thought to be caused by human T-cell leukemia/lymphotropic virus type III (HTLV-III). Since the fall of 1982, independent isolates of HTLV-III have been obtained in this laboratory, in collaboration with several clinical groups, from 101 AIDS and ARC patients and healthy donors at risk for AIDS. Most isolates were from peripheral blood T lymphocytes established in cell culture, but some were obtained from bone marrow, lymph node, brain tissue, and cell-free plasma and from cells associated with saliva, cerebrospinal fluid, and semen. Virus was isolated from approximately 50% of AIDS patients, 85% of ARC patients, and 30% of healthy individuals at risk for AIDS. The risk groups included homosexuals, promiscuous heterosexuals, i.v. drug users, recipients of blood or blood products, and spouses and offspring of AIDS patients and others at risk for AIDS. A high correlation was seen between persistent levels of serum antibody and the ability to isolate virus from patient or donor leukocytes. Immunologic and nucleic acid analysis demonstrated that the virus isolates were highly related, although substantial diversity was observed in the restriction enzyme cleavage patterns of those studied in detail. Biological analysis of cells from infected patients and donors as well as from normal peripheral blood mononuclear cells exposed to virus in vitro demonstrated that OKT4/Leu3a+ (helper/inducer) lymphocytes were preferentially infected and were subjected to a characteristic cytopathic effect. The availability of multiple isolates of virus from a number of different patients and donors will greatly facilitate the characterization of HTLV-III and the study of possible biological and/or biochemical variants of the virus responsible for the development of AIDS, ARC, and related diseases.

Acquired Immunodeficiency Syndrome↗
PubMed1985

Inhibition of platelet function by uremic middle molecules.

To further define the platelet abnormality responsible for uremic bleeding, we studied platelet aggregation with adenosine diphosphate, ristocetin, and collagen in serum fractions obtained by Sephadex G-15 chromatography. We found that uremic patients had considerable inhibition in several peaks of middle molecular range, but the findings were inconsistent and not clearly related to the degree of uremia.

Blood Platelets↗
PubMed1985

[125I]Aminobenzyladenosine, a new radioligand with improved specific binding to adenosine receptors in heart.

The density of adenosine receptors in membranes derived from rat hearts in 25 times lower than the density of receptors in rat brain membranes. Consequently, adenosine radioligands which are useful in brain such as l-[3H]phenylisopropyladenosine, [3H]cyclohexyladenosine, [3H]-2-chloroadenosine and l-[125I]hydroxyphenylisopropyladenosine are of limited usefulness in heart, due to a high ratio of nonspecific to specific binding. We have synthesized a new radioligand, [125I]-N6-4-aminobenzyladenosine, which binds to rat heart membranes with one-sixth the nonspecific binding of the other radioligands. [125I]-N6-4-aminobenzyladenosine bound to rat ventricle membranes with a KD equivalent to that of l-[125I]hydroxyphenylisopropyladenosine and a Bmax of 15.2 fmol/mg protein. [125I]-N6-4-aminobenzyladenosine bound with a higher affinity to brain (KD = 1.93 nM) than to heart membranes (KD = 11.6 nM). At the radioligand KD, 60% of the total [125I]-N6-4-aminobenzyladenosine bound to heart membranes was specifically bound. Iodination of aminobenzyladenosine increased its affinity for the adenosine receptor by 22-fold, possibly due to a steric or hydrophobic effect of iodine. The new ligand was found to be a full adenosine agonist based on its ability to inhibit cyclic adenosinemonophosphate accumulation in isolated embryonic chick heart cells and rat adipocytes. [125I]-N6-4-Aminobenzyladenosine bound to a single affinity site and was displaced from cardiac and brain adenosine receptors by other adenosine analogues with a potency order of l-phenylisopropyladenosine greater than 5'-N-ethylcarboxamide adenosine. These characteristics suggest that the radioligand binds to an Ri adenosine receptor.

Adenosine↗