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Biomedical subjects

A Smith

Publications and source records attributed to A Smith.

At least 1,099 records · Page 61Linked to original sources
PubMed1985

Prevalence of type-specific group B streptococcal antibody in human sera: a study of 405 pregnant women.

Presence of immunoglobulin G antibody against the five standard serotypes of group B streptococcus was measured by means of indirect immunofluorescence in the sera of 405 women at the time of delivery in the obstetric hospital in Vancouver. Antibody to all five serotypes was present in 22% of women whereas only 9.6% had no detectable antibody to any serotype. Among 47 women with group B streptococcus vaginal colonization, IgG antibody was detected against the homologous colonizing serotype in 100%, 75%, 78%, 89%, and 100% of sera for serotypes Ia, Ib, Ic, II, and III, respectively. This contrasted with the women who had heterologous group B streptococcal vaginal colonization or no colonization in whom 71% had serum IgG antibody to serotype Ia, 36% to Ib, 51% to Ic, 66% to II, and 60% to III. Overall the serum antibody titers were low, and few women had titers greater than 1:20 for any of the five standard serotypes.

Antibodies, Bacterial↗
PubMed1985

Interactions with glutathione S-transferases of porphyrins used in photodynamic therapy and naturally occurring porphyrins.

Several naturally occurring porphyrins and porphyrins used in photodynamic therapy inhibit glutathione S-transferase isoenzymes either purified from rat liver or lung or in cytosol from normal and from cancerous (Morris 7288C hepatoma) liver. Although differences occur in the type and amount of transferases in normal and cancerous liver and in the liver of rats bearing an extrahepatic tumour, these enzymes are potential binding sites for porphyrins. Porphyrin structure is an important factor in determining the affinity of binding, as shown by the relative inhibitory effectiveness. Of the dicarboxylic porphyrins in the mixture used clinically, OO'-diacetylhaematoporphyrin and monohydroxyethylmonovinyldeuteroporphyrin are more effective inhibitors than haematoporphyrin and protoporphyrin IX. Of the naturally occurring porphyrins the order of effectiveness is protoporphyrin IX (dicarboxylic) greater than coproporphyrin (tetracarboxylic) greater than uroporphyrin (octacarboxylic) and type I greater than type III isomers of both uroporphyrin and coproporphyrin, and the synthetic tetra-meso-phenylporphinetetrasulphonate is a better inhibitor (apparent Ki = 250 nM) than coproporphyrin, which contains a comparable number of negative charges. In addition, iron-porphyrin chelates are more effective inhibitors of the transferases, with 25-fold decrease in Ki value, than the free porphyrins. These results indicate that one means whereby porphyrins accumulate in tissues is the occupation of intracellular binding sites, such as the transferases. Since porphyrins inhibit the activity of these important detoxifying enzymes, there will be metabolic consequences to the cell.

Animals↗
PubMed1985

Hemopexin-mediated heme transport to the liver. Evidence for a heme-binding protein in liver plasma membranes.

Isolated liver plasma membranes interact with heme-hemopexin and effect the removal of heme from the complex. This heme is rapidly accumulated by a previously undescribed heme-binding membrane component (HBC). This intrinsic membrane component can be solubilized from the membrane with Triton X-100 in a form that retains the ability to bind heme. Solubilized HBC was shown to be distinct from hemopexin itself, free heme, ligandin, globin, heme oxygenase, cytochrome P-450, and albumin. Since formation of the heme-HBC complex is effected by the interaction of heme-hemopexin with its receptor, HBC may either be a subunit of the heme-hemopexin receptor or a separate protein that interacts with the receptor. HBC can also bind heme (Kd apparent 200 nM) that is presented to it in a nonprotein bound form, showing true heme-binding activity. HBC is proteinaceous since treatment with proteases, heat, and disulfide bond reducing agents diminishes its ability to bind heme. HBC and any associated detergent elutes from Sephacryl S-200 with an apparent molecular weight of 115,000 and Stokes radius of 7.5 nm. This component, which may comprise 0.5% of liver plasma membrane protein, appears to have an acidic pI since it adsorbs to DEAE-cellulose at pH 7.4 but not to CM-cellulose at pH 6.4. In sucrose gradients, HBC migrates with S values of 1.69 and 4.02, suggesting that it has subunits or that it forms multimers under these conditions.

Animals↗
PubMed1985

Mucoepidermoid carcinoma arising in an intraparotid lymph node.

A well-differentiated mucoepidermoid carcinoma that was confined to, and apparently arose within, an intraparotid lymph node is reported. Salivary gland ducts and acini often are found within intraparotid lymph nodes, and occasionally within extraparotid nodes. Salivary gland tumors, both benign and malignant, can develop within this ectopic salivary tissue. When a malignant salivary-gland-type neoplasm is found within an intraparotid or periparotid lymph node, the possibility exists that the tumor has arisen within the node and does not necessarily represent a metastasis from some other occult site.

Adult↗
PubMed1985

Penicillamine-induced ocular myasthenia gravis.

Two patients with rheumatoid arthritis (two women, 58 and 62 years old) developed reversible penicillamine-induced ocular myasthenia gravis. Both had the HLA-DR1 antigen, unlike most patients with idiopathic myasthenia gravis who show HLA-DR3, suggesting that penicillamine-induced myasthenia gravis and its idiopathic counterpart occur in patients with different genetic backgrounds. In both cases, cessation of drug treatment led to resolution of the symptoms.

Eye Diseases↗
PubMed1985

In vivo distribution studies of radioactively labelled platinum complexes; cis-dichlorodiammine platinum(II), cis-trans-dichlorodihydroxy-bis-(isopropylamine) platinum(IV), cis-dichloro-bis-cyclopropylamine platinum(II), and cis-diammine 1,1-cyclobutanedicarboxylate platinum(II) in patients with malignant disease, using a gamma camera.

The in vivo distribution in man of the four platinum derivatives cis-dichlorodiammine platinum(II) (DDP), cis-trans-dichlorodihydroxy-bis-(isopropylamine) platinum (IV) (CHIP), cis-dichloro-bis-cyclopropylamine platinum(II) (CP), and cis-diammine 1, 1-cyclobutanedicarboxylate platinum(II) (CBDCA) has been observed. The availability of these compounds labelled with the radioactive isotope of platinum, platinum-191, has made serial in vivo imaging of their distribution possible. Injection of 17-35 MBq (5-28 mg) of the labelled compound IV was followed by imaging, using a gamma camera, with particular reference to the kidneys, liver, and tumour site. Hepatic and renal clearances were observed in all nine patients, but no unequivocal evidence of tumour uptake was found. The left kidney uptake was estimated at times up to 7 days after injection. Mathematical analysis of some of the uptake curves failed to show any significant difference between the clearance times observed. However, the two patients who received CBDCA did show a higher initial renal uptake, falling within the 1st day to levels comparable with those of the other compounds, and the three patients who received DDP showed consistently liver uptake.

Adult↗
PubMed1985

Distribution of the human jaw stretch reflex response elicited by percutaneous, localized stretch of jaw-closing muscles.

In the present study homonymous and heteronymous projections of muscle spindle afferent fibers in the human jaw-closing system were investigated. Stretch reflex responses were elicited with percutaneous displacement stimuli applied to the belly of the anterior superficial divisions of temporalis and masseter muscles. The distribution of reflex responses in jaw-closing muscles was assessed. Reflex responses to this stimulus were observed in all jaw-closing muscles ipsilateral to the stimulated muscle, suggesting that the projection of spindle afferent fibers to jaw-closing muscles in humans is diffuse. Comparisons of homonymous and heteronymous reflex response amplitudes indicated that homonymous response amplitudes tended to be larger. However, the relative strength of heteronymous inputs to masseter motoneurons appeared to be stronger than those to temporalis motoneurons.

Adult↗
PubMed1985

Reflex responses of the human jaw-closing system depend on the locus of intraoral mechanical stimulation.

Innocuous mechanical stimuli were applied to eight sites on the tongue dorsum and palate while subjects used feedback to maintain a constant isometric biting force. Reflex responses of the jaw-closing system were measured as changes in force and in EMGs recorded from right and left masseter muscles. Stimulation at each of the eight sites produced reflex force and EMG responses in most subjects tested. The nature of the reflex responses strongly depended on the site of stimulation. Stimulation of the palate tended to produce suppression of ongoing EMG activity and decreases in background biting force. In contrast, stimulation of sites on the tongue posterior to the tip, most often resulted in excitatory EMG responses and increases in jaw-closing force. Unilateral, early excitatory responses were observed in the right masseter with stimulation of the right side of the tongue. The existence of spatially organized responses of the human jaw-closing system to innocuous intraoral stimulation is not consistent with the view that these cutaneous reflexes are primarily of protective significance.

Adolescent↗
PubMed1985

Amyloidosis with oral involvement.

Amyloidosis is a disease complex in which amyloid fibrils, formed from various serum proteins, may be deposited in a local or systemic distribution. When this deposition affects vital organs the disease usually is fatal because there is no effective treatment. This paper reports a case of amyloidosis with oral involvement and discusses recent advances concerning the properties of amyloid fibrils and the various pathogenic mechanisms responsible for their formation.

Aged↗
PubMed1985

Reflex responses of human lip muscles to mechanical stimulation during speech.

The role played by reflex pathways in the production of movement has been a significant issue for motor control theorists interested in a wide variety of motor behaviors. From studies of locomotion and chewing, it appears that gains in reflex pathways can be altered so that activity in these pathways does not produce destabilizing responses during movement. In speech production, recent experimental evidence has been interpreted to suggest that autogenetic lip reflexes (perioral reflexes) are suppressed during sustained phonation or speech production. The present study was conducted to assess the effects of phonation, direction of movement, and ongoing speech production on reflex responses of lip muscles. The present results suggest, in contrast to earlier work, that this reflex pathway is not suppressed or absent because the amplitude of the observed response depends upon the activation levels of the various muscles of the lower lip and, therefore, indirectly on the nature of the gesture the subject is instructed to produce.

Journal Article↗
PubMed1985

Ultrasound guided chorion biopsy in antenatal diagnosis of genetic disorders.

The technique of transcervical chorion biopsy was evaluated in women about to undergo therapeutic termination of pregnancy. The trophoblast biopsy catheter (Portex) under real-time ultrasound guidance was the most reliable in obtaining chorionic villi. The overall success rate for chorion biopsy was 73% in the first 100 patients studied.

Biopsy↗
PubMed1985

Quantitation of ciprofloxacin in body fluids by high-pressure liquid chromatography.

We describe a reverse-phase high-pressure liquid chromatography method for the quantitation of a new quinoline carboxylic acid antimicrobial agent, ciprofloxacin (Bay o 9867). This assay utilizes the intrinsic fluorescence of ciprofloxacin for primary detection but employs UV absorption as a secondary detection system. Mobile phases contained methanol and phosphate buffer and used a common C18 mu Bondapak column. A single precipitation step of a 50-microliter specimen was the only sample preparation necessary. The assay is linear from 2,000 to 10 ng/ml and sensitive to 5 ng/ml. The mean recovery of ciprofloxacin from serum was 105.7%. The coefficient of variation was less than or equal to 3.1% for same-day precision and less than or equal to 6.3% for assay-to-assay precision. Because the assay requires only small specimen volumes and minimal sample preparation and because of its defined characteristics, this assay would be ideal for clinical trials and pharmacokinetics studies of ciprofloxacin.

Anti-Infective Agents↗
PubMed1985

In vitro activities of enoxacin, ticarcillin plus clavulanic acid, aztreonam, piperacillin, and imipenem and comparison with commonly used antimicrobial agents.

A total of 745 gram-negative and 313 gram-positive clinical isolates were tested against enoxacin, ticarcillin plus clavulanic acid, aztreonam, imipenem, and piperacillin and compared with commonly used antimicrobial agents. Ticarcillin plus clavulanic acid, imipenem, and piperacillin were active against Pseudomonas aeruginosa and Acinetobacter spp. and most Pseudomonas spp. Aztreonam was active against members of the family Enterobacteriaceae but was less effective against the nonfermenters. Enoxacin was active against the Enterobacteriaceae, P. aeruginosa, the staphylococci, and most Acinetobacter spp. but was less active against Pseudomonas spp. and streptococci. Imipenem was very active against all gram-positive and -negative organisms tested except for Pseudomonas maltophilia.

Anti-Bacterial Agents↗
PubMed1985

Serial measurement of plasma arginine vasopressin in the newborn.

Plasma arginine vasopressin was measured serially in 11 preterm infants and one asphyxiated, term infant. The samples were taken through umbilical arterial catheters placed at birth for blood gas measurements because ventilatory support was required. Plasma samples of 200 to 300 microliter were taken 4 to 12 hourly for up to 100 hours after birth. Plasma arginine vasopressin was measured by a cytochemical bioassay. A significant correlation between plasma arginine vasopressin and plasma osmolality was found in only two out of six infants. The normal 'resting' concentration was between 0.5 and 2 pg/ml. In five infants, apparent bursts of arginine vasopressin secretion were seen, and in one spontaneously breathing infant with respiratory distress, continuously high concentrations (12 to 25 pg/ml) were recorded over the first 100 hours.

Aging↗