Biomedical subjects
H C Patel
Publications and source records attributed to H C Patel.
A case of Charles Bonnet syndrome with musical hallucinations.
An 86-year-old woman with visual impairment who developed a vivid, visual hallucinatory state in clear sensorium is described. This picture conforms to the description of Charles Bonnet Syndrome. She also experienced musical hallucinations. The role of sensory deprivation in the pathogenesis of this syndrome is discussed.
Effect of biotin on alkaloid production during submerged cultivation of Claviceps sp. strain SD-58.
Addition of biotin to culture medium NL-406 significantly increased alkaloid yield during submerged cultivation of Claviceps sp. strain SD-58. Alkaloid yield was further enhanced by incorporating leucine in biotin-supplemented culture medium. Increased alkaloid production was associated with an increase in the lipid content of cells and in the number of chlamydospores. Biotin deficiency caused a reduction in alkaloid yield and a parallel decrease in lipid content and chlamydospore numbers.
In vitro and in vivo comparison of sulfur donors as antidotes to acute cyanide intoxication.
Antidotes for cyanide (CN) intoxication include the use of sulfane sulfur donors (SSDs), such as thiosulfate, which increase the conversion of CN to thiocyanate by the enzyme rhodanese. To develop pretreatments that might be useful against CN, SSDs with greater lipophilicity than thiosulfate were synthesized and assessed. The ability of SSDs to protect mice against 2LD50 of sodium cyanide (NaCN) administered either 15 or 60 min following administration of an SSD was assessed. To study the mechanism of action of the SSD, the candidate compounds were examined in vitro for their effect on rhodanese and 3-mercaptopyruvate sulfurtransferase (MST) activity under increasing SSD concentrations. Tests were conducted on nine candidate SSDs: ICD1021 (3-hydroxypyridin-2-yl N-[(N-methyl-3-aminopropyl)]-2-aminoethyl disulfide dihydrochloride), ICD1022, (3-hydroxypyridin-2-yl N-[(N-methyl-3-aminopropyl)]-2-aminoethyl disulfide trihydrochloride), ICD1584 (diethyl tetrasulfide), ICD1585 (diallyl tetrasulfide), ICD1587 (diisopropyl tetrasulfide); ICD1738 (N-(3-aminopropyl)-2-aminoethyl 2-oxopropyl disulfide dihydrochloride), ICD1816 (3,3'-tetrathiobis-N-acctyl-L-alanine), ICD2214 (2-aminoethyl 4-methoxyphenyl disulfide hydrochloride) and ICD2467 (bis(4-methoxyphenyl) disulfide). These tests demonstrated that altering the chemical substituent of the longer chain sulfide modified the ability of the candidate SSD to protect against CN toxicity. At least two of the SSDs at selected doses provided 100% protection against 2LD50 of NaCN, normally an LD99. All compounds were evaluated using locomotor activity as a measure of potential adverse behavioral effects. Positive hypoactivity relationships were found with several disulfides but none was found with ICD1584, a tetrasulfide. Separate studies suggest that the chemical reaction of potassium cyanide (KCN) and cystine forms the toxic metabolite 2-iminothiazolidine-4-carboxylic acid. An alternative detoxification pathway, one not primarily involving the sulfur transferases. may be important in pretreatment for CN intoxication. Although studies to elucidate the precise mechanisms are needed. it is clear that these newly synthesized compounds provide a new rationale for anti-CN drugs, with fewer side-effects than the methemoglobin formers.
Synthesis, crystal structure, and molecular conformation of N-Boc-L-Phe-dehydro-Leu-L-Val-OCH3.
The peptide N-Boc-L-Phe-dehydro-Leu-L-Val-OCH3 was synthesized by the usual workup procedure and finally by coupling the N-Boc-L-Phe-dehydro-Leu-OH to valine methyl ester. It was crystallized from its solution in methanol-water mixture at 4 degrees C. The crystals belong to the triclinic space group P1 with a = 5.972(5) A, b = 9.455(6) A, c = 13.101(6) A, alpha = 103.00(4) degrees, beta = 97.14(5) degrees, gamma = 102.86(5) degrees, V = 690.8(8) A, Z = 1, dm = 1.179(5) Mg m-3 and dc = 1.177(5) Mg m-3. The structure was determined by direct methods using SHELXS86. It was refined by block-diagonal least-squares procedure to an R value of 0.060 for 1674 observed reflections. The C alpha 2-C beta 2 distance of 1.323(9) A in dehydro-Leu is an appropriate double bond length. The bond angle C alpha-C beta-C gamma in the dehydro-Leu residue is 129.4(8) degrees. The peptide backbone torsion angles are theta 1 = -168.6(6) degrees, omega 0 = 170.0(6) degrees, phi 1 = -44.5(9) degrees, psi 1 = 134.5(6) degrees, omega 1 = 177.3(6) degrees, phi 2 = 54.5(9) degrees, psi 2 = 31.1(10) degrees, omega 2 = 171.7(6) degrees, phi 3 = 51.9(8) degrees, psi T3 = 139.0(6) degrees, theta T = -175.7(6) degrees. These values show that the backbone adopts a beta-turn II conformation. As a result of beta-turn, an intramolecular hydrogen bond is formed between the oxygen of the ith residue and NH of the (i + 3)th residue at a distance of 3.134(6) A.(ABSTRACT TRUNCATED AT 250 WORDS)
Trends in head injury outcome from 1989 to 2003 and the effect of neurosurgical care: an observational study.
BACKGROUND: Case fatality rates after all types of blunt injury have not improved since 1994 in England and Wales, possibly because not all patients with severe head injury are treated in a neurosurgical centre. Our aims were to investigate the case fatality trends in major trauma patients with and without head injury, and to establish the effect of neurosurgical care on mortality after severe head injury. METHODS: We analysed prospectively collected data from the Trauma Audit and Research Network database for patients presenting between 1989 and 2003. Mortality and odds of death adjusted for case mix were compared for patients with and without head injury, and for those treated in a neurosurgical versus a non-neurosurgical centre. FINDINGS: Patients with head injury (n=22,216) had a ten-fold higher mortality and showed less improvement in the adjusted odds of death since 1989 than did patients without head injury (n=154,231). 2305 (33%) of patients with severe head injury (presenting between 1996 and 2003) were treated only in non-neurosurgical centres; such treatment was associated with a 26% increase in mortality and a 2.15-fold increase (95% CI 1.77-2.60) in the odds of death adjusted for case mix compared with patients treated at a neurosurgical centre. INTERPRETATION: Since 1989 trauma system changes in England and Wales have delivered greater benefit to patients without head injury. Our data lend support to current guidelines, suggesting that treatment in a neurosurgical centre represents an important strategy in the management of severe head injury.
A 3D-QSAR study of anticoccidial triazines using molecular shape analysis.
A set of 54 anticoccidial triazine analogs were analyzed in terms of molecular shape analysis, MSA, with the goal of constructing a three-dimensional quantitative structure-activity relationship (3D-QSAR). This same dataset was previously investigated using alternate QSAR methods including comparative molecular field analysis (CoMFA). A complete 3D-QSAR was realized using MSA which included (a) identification of the active conformation of each individual analog, (b) the relative intramolecular stability of each analog in its active conformation, (c) general intramolecular stability requirements for activity, (d) a statistically significant correlation equation, and (e) mapping of the receptor space explored by the analogs. The MSA-3D-QSAR indicates that the steric shape and dipole moment of each analog governs its activity. The MSA-3D-QSAR correlation equations are more predictive than other QSARs as measured by cross-validation correlation coefficients.
Chlamydial ocular infection: efficacy of partner notification by patient referral.
Records on 254 patients with chlamydial ocular infection observed over a period of 67 months at the Moorfield's Eye Hospital were reviewed retrospectively in relation to sexual partners in the 6 months prior to diagnosis. Contactable partners were given an appointment through index patients to attend our clinic. Those unable to attend were issued contact slips, as used by the sexually transmitted disease (STD) clinics in the United Kingdom, to attend elsewhere: 175/328 (53%) of all partners were seen in our clinic: 161/218 (74%) of current regular partners compared to only 7/57 (12%) of ex-regular and 7/53 (13%) of casual partners. However, of those given appointments 175/201 (87%) attended: 161/179 (90%) of current regular, 7/14 (50%) of ex-regular and 7/8 (88%) of casual partners. Seventy of 328 (21%) of all partners were issued contact slips, of whom 47/70 (67%) were reported to have attended elsewhere. No contact slips were returned by other clinics, indicating a failure in the contact slip system. Thirty-five of 53 (66%) of casual, 22/57 (39%) of ex-regular and none of the current regular partners were untraceable. One hundred and five of 196 (54%) female partners were examined, of whom 59/105 (56%) had chlamydial genital infection, 45/105 (43%) had other genital infections and 35/105 (33%) had multiple genital infections. Seventy of 132 (53%) male partners were examined, of whom 58/70 (83%) had chlamydial or non-specific urethritis, 5/70 (7%) had other genital infections and 4/70 (6%) had multiple genital infections. Partner notification is important to interrupt chlamydia transmission.(ABSTRACT TRUNCATED AT 250 WORDS)