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A Philip

Publications and source records attributed to A Philip.

At least 55 records · Page 3Linked to original sources
PubMed1989

Low polarity ligands of sex hormone-binding globulin in pregnancy. Part II--Identification.

Certain previously unrecognized ligands of SHBG of low polarity in pregnancy were identified. They include two weakly bound compounds: 5 alpha-pregnane-3,20-dione and progesterone; and two strongly bound substances, 2-methoxyestrone and a new steroid, estradienolone (17 beta-hydroxy-1,5-estradiene-3-one). The identification of the first three peaks was based on chromatographic elution patterns, binding characteristics and gas chromatography-mass spectrometry. The identification of the fourth peak, the new steroid, was based on similar kinds of evidence and, in addition, solubility characteristics and ultraviolet absorption spectrum.

5-alpha-Dihydroprogesterone↗
PubMed1989

Massage-enhanced insulin absorption--increased distribution or dissociation of insulin?

Massage over the site of a subcutaneous insulin injection markedly enhances the absorption of insulin. To investigate whether this reflects an increased dispersion of insulin in the tissue, the area of distribution of radioactivity at 125I-insulin (10 U) injection sites in thigh was determined in eight healthy volunteers by external scanning on a day with standardized massage and on a control day. Insulin absorption (first order disappearance rate constants and appearance of serum immunoreactive insulin, IRI) and plasma glucose were determined concomitantly. The area of distribution of 125I increased 30 +/- 15% (p less than 0.05) on the massage day, which was not significantly different from the change during control (12 +/- 10%). The rate constants for 125I-insulin increased markedly (237 +/- 74%) on the massage day and much less (49 +/- 15%) on the control day (p less than 0.01). Peak IRI levels were 49 +/- 8 mU/l on the massage day and 17 +/- 2 mU/l on the control day (p less than 0.01). The glucose lowering effect was also more pronounced on the massage day. These results indicate that the marked enhancement of insulin absorption induced by massage of the injection site is not directly related to expansion of the insulin depot in the subcutaneous tissue.

Adult↗
PubMed1988

1,2,4-Trioxanes as potential antimalarial agents.

A number of 1,2,4-trioxanes were prepared and tested for antimalarial activity in search of a simplified analogue of the naturally occurring antimalarial qinghaosu. The compounds were assayed in an in vitro system for antimalarial activity against chloroquine-susceptible and chloroquine-resistant strains of Plasmodium falciparum. The most active compounds were methyl 2-(2,4a-epidioxy-4a,5,6,7,8,8a-hexahydro-5,5,8a-trimethyl-2H-1-benzop yra n-2-yl) acetate (3b), which showed IC20's of 96 and 39 ng/mL, respectively, and 2,4a-epidioxy-3,4,4a,5,6,7,8,8a-octahydro-2-[2-(benzoyloxy)propyl]-5,5,8 a- trimethyl-2H-1-benzopyran (12), which showed IC50's of 24 and 99 ng/mL, respectively. For comparison, qinghaosu exhibits an IC50 of 1 ng/mL for both strains.

Animals↗
PubMed1988

Peptide derivatives of primaquine as potential antimalarial agents.

Three peptide derivatives of primaquine were synthesized. The compounds were tested for radical curative antimalarial activity against Plasmodium cynomolgi in rhesus monkeys and blood schizonticidal antimalarial activity against Plasmodium berghei in mice. All three peptide derivatives showed activity against P. cynomolgi greater than that expected for the primaquine content of each prodrug. The toxicity of one of the peptide derivatives was less than that of primaquine in mice.

Animals↗
PubMed1987

Endoperoxides as potential antimalarial agents.

A number of mono- and bicyclic endoperoxides were prepared and tested for antimalarial activity in search of a simplified analogue of the 5-oxygen-substituted 1,2,4-trioxane ring structure of the naturally occurring antimalarial qinghaosu. The compounds were assayed in an in vitro system for antimalarial activity against chloroquine-susceptible and chloroquine-resistant strains of P. falciparum. The most active compound in this assay was 2-[((butyloxy)-carbonyl)oxy]-1,1,10-trimethyl-6,9-epidioxy-delta 7-octalin (17a), which showed an IC50 of 100 and 57 ng/mL, respectively. For comparison, qinghaosu exhibits a mean IC50 less than 3.4 ng/mL.

Animals↗
PubMed1987

An agar culture technique to quantitate Trichomonas vaginalis from women.

In subjects with trichomoniasis the number of Trichomonas vaginalis in vaginal discharges or secretions is unknown. The presence of T. vaginalis was evaluated in 177 consecutive female patients attending an inner city sexually transmitted disease clinic by patient history, wet mount, and broth culture. T. vaginalis was quantitated by a novel agar culture technique. Of the 177 women, 86 (49%) were positive for T. vaginalis by either wet mount or culture. Clinical symptoms were not reliable for making an accurate diagnosis of trichomoniasis. Culture on modified Diamond's medium was more sensitive (98%) than the wet mount method (38%) in detecting T. vaginalis. Of the 86 patients who were positive for trichomoniasis, quantitation was obtained for 81 patients, with 70% yielding greater than 10(4) colony-forming units (cfu)/ml. The number of T. vaginalis ranged from 40 to greater than 10(6) cfu/ml. The wet mount method was very insensitive for detecting T. vaginalis and was positive only in patients yielding greater than 10(5) cfu/ml.

Adolescent↗
PubMed1986

Relative binding of certain steroids of low polarity to human sex hormone-binding globulin: strong binding of 2-methoxyestrone, a steroid lacking the 17 beta-OH group.

The cross-reactivities for binding sites on human sex hormone-binding globulin (SHBG) of a number of steroids of low polarity, including progesterone and estrogen metabolites, were studied. Binding relative to testosterone (100%) was low (less than or equal to 3%) except for 2-methoxyestrone (81%), 3-acetoxyestradiol (16%), 4-methoxyestradiol (6%), 3 beta-hydroxy-5 beta-pregnan-3-one (5.8%), 5 alpha-dihydrodeoxycorticosterone (4.5%), deoxycorticosterone (4%), 20 alpha-hydroxy-5 alpha-pregnan -3-one (4%), 4-methoxyestrone (4%) and 5 alpha-dihydroprogesterone (3.5%). 2-Methoxyestrone is the only steroid lacking a 17 beta-hydroxyl group which binds to SHBG with strong affinity.

Binding, Competitive↗
PubMed1986

Enzymatic synthesis of a false cholinergic neurotransmitter: diethylaminoethyl acetate as a muscarinic agonist analog of acetylcholine.

Diethylaminoethyl acetate, an acetylcholine analog, was formed upon the incubation of diethylaminoethanol and acetyl-CoA with bovine brain choline acetyltransferase (acetyl-CoA: choline O-acetyltransferase; EC 2.3.1.6). The new product co-chromatographed with authentic diethylaminoethyl acetate on thin layer plates, and its formation was proportional to the duration of incubation and enzyme concentrations. When tested on guinea-pig ileum, diethylaminoethyl acetate was found to be an agonist with an ED50 of 1.3 X 10(-4) M, compared to an ED50 of 2.0 X 10(-7) M for acetylcholine. The contraction of guinea-pig ileum induced by diethylaminoethyl acetate was blocked by atropine. Moreover, diethylaminoethyl acetate induced a secretion of alpha-amylase from isolated pancreatic acini cells; this effect was also blocked by atropine. It is entirely possible that diethylaminoethyl acetate can be a false cholinergic transmitter generated in vivo when drugs such as aprophen or procaine are administered to animals, since either of these drugs can undergo enzymatic hydrolysis to generate diethylaminoethanol. A method for the synthesis of radioactive diethylamino [1,2-14C]ethyl acetate was also described.

Acetylcholine↗
PubMed1986

Rapid assay for immunological detection of Trichomonas vaginalis.

Trichomoniasis is a common sexually transmitted disease with an estimated incidence of 4 million to 8 million cases a year in the United States. The most commonly used method of diagnosis is a direct microscopic observation (wet mount) of vaginal secretions and, although both rapid and inexpensive, the sensitivity of this technique is generally 50 to 70%. We developed an indirect enzyme-linked immunosorbent assay (ELISA) for the detection of Trichomonas vaginalis which is both rapid and sensitive (detection limit of approximately 100 trichomonads per ml). This assay, which employs affinity-purified rabbit anti-T. vaginalis antibodies in a "sandwich" configuration, is simple to perform and is neither interfered with nor appears to cross-react with other microorganisms which are common inhabitants of the urogenital tract. One hundred and seventy-seven consecutive unselected patients attending a clinic for sexually transmitted diseases were evaluated for trichomoniasis by a broth culture technique monitored for up to 7 days (and considered here to be the standard for positivity), the conventional wet mount method, a solid culture procedure, and the ELISA. Of these, 84 were positive by culture; 33 were positive by the wet mount; and despite the fact that the vaginal specimens were diluted 20-fold during the culture procedures prior to testing in the ELISA, 65 were positive by ELISA. In addition to exhibiting a sensitivity of 77%, the specificity of the ELISA was 100%. These results demonstrate that the ELISA is a significant improvement over the wet mount method for the diagnosis of trichomoniasis.

Antigens, Protozoan↗
PubMed1985

Estrogen formation in the developing rat brain: sex differences in aromatase activity during early post-natal life.

Aromatase activity in the brain of the rat was measured during perinatal development and in adulthood. In pooled hypothalamus, preoptic area, septum and amygdala (HPAS), estrogen formation per gram protein increased between embryonic days 15 and 19 and then declined. Results for males and females were indistinguishable, except for post-natal days 1 and 2 and 3 and 4 when estrogen formation was significantly higher in the male. Aromatization was not convincingly demonstrated in cerebral cortical tissue at any time studied. Regional dissection of the HPAS in 2-3 day post-natal animals revealed significant sex differences in aromatase activity in the corticomedial amygdala and the hypothalamus, but not in the preoptic-septal region or the remainder of the amygdala. These results are consistent with the idea that perinatal androgen secretion in the male rat may stimulate estrogen formation in the brain.

Age Factors↗
PubMed1985

Comparative evaluation of five commercial systems for the rapid identification of pathogenic Neisseria species.

Prompt diagnosis and effective treatment of urogenital gonococcal infections require rapid isolation and identification of Neisseria gonorrhoeae from urogenital specimens. We evaluated a new, rapid (30-min) test called Gonochek II (E-Y Laboratories, San Mateo, Calif.) which utilizes chromogenic substrates for the identification of pathogenic Neisseria species. It was compared with the API NeIdent (Analytab Products, Inc., Plainview, N.Y.), Minitek (BBL Microbiology Systems, Cockeysville, Md.), and RapID NH (Innovative Diagnostics, Atlanta, Ga.), systems and the Phadebact GC (Pharmacia Diagnostics, Piscataway, N.J.) test for its performance in identifying known strains of N. gonorrhoeae (39 strains), Neisseria meningitidis (22 strains), Neisseria lactamica (12 strains), and Branhamella catarrhalis (17 strains). The Gonochek II system correctly identified 100% of N. gonorrhoeae, N. lactamica, and B. catarrhalis strains and 95.4% of N. meningitidis strains. The percent agreement for correct identification of all strains tested was 98.8%. In contrast, the Minitek, RapID NH, and API NeIdent systems correctly identified 86.6, 80.0, and 73.3% of the strains, respectively. The Phadebact GC test identified 94.9% of the N. gonorrhoeae isolates but also cross-reacted with 41.6% of the N. lactamica strains. The Gonochek II system is rapid, simple to perform, and easy to interpret, requires 1 to 2 min to set up, and more accurately identifies pathogenic Neisseria species when compared with other systems used in this study.

Cost-Benefit Analysis↗
PubMed1985

Absorbed doses at varying tube voltage in lateral cephalography.

Absorbed doses in organs of special interest from lateral cephalography were measured by thermoluminescence dosimetry in a tissue equivalent phantom head. The radiographic examination was performed in a standardized manner by using a carefully collimated radiation field and a near-focus dodger. The actual tube voltages ranged from 63-127 kVp. The absorbed dose was described as a function of tube voltage. In all measurement sites the absorbed dose decreased with increasing tube voltage. This reduction was most obvious in the low tube voltage range. From the results a lowest recommendable tube voltage was given for the different measurement sites varying from approximately 75 kVp (thyroid region) to approximately 100 kVp (parotid region). A high tube voltage was found to be important for a low absorbed dose in different organs in lateral cephalography.

Bone Marrow↗
PubMed1984

Does sex hormone-binding globulin play a role in the transport of estradiol in vivo?

The distribution of estradiol and testosterone into sex hormone-binding globulin (SHBG)-bound, albumin-bound, and unbound fractions in whole serum under equilibrium conditions at 37 degrees C is described in women with normal menstrual cycles, pregnant women, and newborn infants. The percentage of estradiol bound to SHBG was determined by equilibrium dialysis at 37 degrees C. Whole serum, 0.1 ml, was dialyzed against 0.1 ml of the same serum heated at 60 degrees C for 1 hour (a procedure shown to denature SHBG but not to affect albumin). The percentage of unbound estradiol in whole serum was measured by dialyzing native serum against an isosmotic dextran solution. Testosterone binding was studied similarly. Our findings show that SHBG is an important binder of estradiol in both pregnant and nonpregnant women. However, estradiol binding by SHBG is undetectable in the newborn infant. Testosterone is significantly bound to SHBG under all circumstances. We conclude that SHBG does play a role in the transport of estradiol in women, particularly in pregnancy.

Adult↗
PubMed1983

Evaluation of API microtube GT system for detection of germ tube production by clinically significant yeasts.

A total of 152 fresh consecutive yeast isolates were tested for their ability to produce germ tubes by the API GT system (Analytab products, Plainview, N.Y.) and by a conventional method. The API system was found to be less sensitive than the conventional method. The costs per test by the API system and the conventional method were $0.76 and $0.39, respectively.

Bacteriological Techniques↗
PubMed1983

Influence of maternal diabetes on fetal rat development: alteration of insulin receptors in fetal liver and lung.

The influence of maternal diabetes on fetal development was studied in rats made diabetic by administration of streptozotocin on day 2 of gestation as well as in genetically diabetic BB Wistar rats. A dose of 65 mg streptozotocin/kg produced severe diabetes with plasma glucose levels of approximately 36 mmol/l, this was associated with fetal growth retardation but not fetal hyperinsulinaemia. In contrast, a smaller dose of streptozotocin (45 mg/kg) produced moderate diabetes with plasma glucose levels of approximately 20 mmol/l and was associated with fetal hyperinsulinaemia but only a marginal effect on fetal size. In both groups of diabetic animals, maternal body weight gain was decreased, maternal plasma insulin levels were low and fetal glucose levels were similar. In a small group of genetically diabetic BB rats on insulin therapy the fetuses were macrosomic and hyperinsulinaemic. The specific binding of 125I-labelled insulin to partially purified liver and lung membranes of fetuses of both groups of streptozotocin-induced diabetic rats was significantly lower than the binding to membranes from fetuses of control animals. The specific binding of 125I-labelled insulin to fetal liver and lung membranes from the diabetic BB Wistar rats also appeared to be reduced when compared to tissues from controls. Decreased insulin receptors in fetal lung and liver of diabetic rats suggest a role for insulin in the development of these organs during the fetal and neonatal period.

Animals↗
PubMed1981

Synthesis and pharmacological activity of thiohexital enantiomers.

(S)-(+)- and (R)-(-)-5-Allyl-5-(1-methyl-2-pentynyl)-2-thiobarbituric acid (1, thiohexital) were prepared. The anesthetic activity (loss of righting reflex) and acute toxicity of the optically pure enantiomers of 1 were compared to the racemic isomer in mice. The S(+) isomer was found to be more potent as an anesthetic agent than the R(-) or RS(+/-) isomers. The therapeutic index was 2.5, 2.4, and 3.2 for the RS(+/-), R(-), and S(+) isomers, respectively. There were no significant differences in onset and duration of anesthesia when administered at the respective AD50 values. The prominent side effect is tremor, which is less for the S(+) isomer than for the R(-) or RS(+/-) isomers.

Anesthetics↗