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Biomedical subjects

A M Smith

Publications and source records attributed to A M Smith.

At least 289 records · Page 16Linked to original sources
PubMed1991

Selenium status of preterm infants fed human milk, preterm formula, or selenium-supplemented preterm formula.

The selenium status of 46 orally fed vitamin E-sufficient preterm infants (birth weight less than 1700 gm) was studied longitudinally for 3 weeks to determine the efficacy of selenium supplementation. Infants were fed either human milk (n = 21; 24 ng selenium/ml), preterm formula (n = 13; 7.8 ng selenium/ml), or preterm formula supplemented with sodium selenite (n = 12; 34.8 ng selenium/ml). Plasma and erythrocyte selenium and glutathione peroxidase activity and urinary and dietary selenium content were evaluated on study day 1 (day enteral feeds reached 100 kcal/kg/day) and weekly for 3 weeks. Throughout the study, selenium intakes of infants fed preterm formula plus sodium selenite were greater than those of infants fed human milk, which were greater than those of infants fed preterm formula (p less than 0.001). After 3 weeks no differences were observed among groups for plasma or erythrocyte selenium or glutathione peroxidase. Plasma selenium and glutathione peroxidase values within all groups were low compared with those reported for term infants fed human milk. Whereas urinary selenium levels of infants fed preterm formula plus sodium selenite were greater than those of infants fed preterm formula at weeks 1 and 2 (p less than 0.01), infants fed human milk and preterm formula had lower levels at week 3 than on study day 1 (p less than 0.05). We conclude that blood selenium measurements typically used to monitor selenium status do not reflect dietary selenium intakes of orally fed preterm infants.

Enteral Nutrition↗
PubMed1991

Topically active carbonic anhydrase inhibitors. 4. [(Hydroxyalkyl)sulfonyl]benzene and [(hydroxyalkyl)sulfonyl]thiophenesulfonamides.

For several decades a tantalizing goal for the treatment of primary open-angle glaucoma has been the development of a topically active carbonic anhydrase inhibitor. Recent results from several research groups indicate that considerable progress has been made toward this objective. In this report, we present the design and synthesis of (hydroxyalkyl)sulfonyl-substituted benzene- and thiophenesulfonamides. These compounds exhibit inhibition of carbonic anhydrase II in the nanomolar range and lower intraocular pressure in the alpha-chymotrypsinized rabbit model of ocular hypertension after topical instillation.

Administration, Topical↗
PubMed1991

Overestimation of monoclonal immunoglobulin by immunochemical methods.

A comparison of paraprotein estimation by scanning densitometry with corresponding immunoglobulin concentration measured by rate immunonephelometry, fixed-time immunonephelometry and kinetic immunoturbidimetry using a large number of sera has indicated overestimation of the immunoglobulin by liquid phase immunoassays in the presence of a monoclonal component. The effect was seen with all three major immunoglobulin isotypes but was most marked with IgM paraproteins when measured by kinetic nephelometry. The overestimations could not be explained by presence of rheumatoid factors or immune complexes in the serum samples, or by non-parallelism, over a range of dilutions, of the reaction of sample and calibrant with the antiserum. The source and species of antiserum used was a major contributory factor.

Antibodies, Monoclonal↗
PubMed1991

What makes war surgery different?

How can our military surgeons be optimally prepared for their roles in the combat setting? The recent training assignment of military surgeons to urban trauma centers is a necessary first step toward this elusive goal, although not conclusive preparation for carrying out surgery in a combat theater. The multiple dimensions of difference between combat and peacetime medical practice require continuing emphasis.

General Surgery↗
PubMed1991

Allergens in Hymenoptera venoms. XXIII. Venom content of imported fire ant whole body extracts.

A two-site immunoassay using monoclonal antibodies has been developed to measure the imported fire ant venom allergen Sol i III. The assay is specific for Solenopsis invicta venom, since one of the monoclonal antibodies does not react with Sol r III. A commercial imported fire ant whole body extract, known from RAST and skin test data to be potent, was found to contain 10.3 micrograms of Sol i III per milliliter. This was comparable to the content of an extract freshly prepared in our laboratory. The immunoassay detected Sol i III in an extract of fire ant abdomens, but not in head and thorax extract. The amount of imported fire ant venom in a potent whole body extract appears to be sufficient to provide possible protection for patients receiving it as immunotherapy, although this can only be verified by controlled clinical trials with intentional sting challenges.

Allergens↗
PubMed1990

The wrinkled-seed character of pea described by Mendel is caused by a transposon-like insertion in a gene encoding starch-branching enzyme.

We describe the cloning of the r (rugosus) locus of pea (Pisum sativum L.), which determines whether the seed is round or wrinkled. Wrinkled (rr) seeds lack one isoform of starch-branching enzyme (SBEI), present in round (RR or Rr) seeds. A major polymorphism in the SBEI gene between near-isogenic RR and rr lines shows 100% cosegregation with the r locus, establishing that the SBEI gene is at the r locus. An aberrant transcript for SBEI is produced in rr embryos. In rr lines the SBEI gene is interrupted by a 0.8 kb insertion that is very similar to the Ac/Ds family of transposable elements from maize. Failure to produce SBEI has complex metabolic consequences on starch, lipid, and protein biosynthesis in the seed.

1,4-alpha-Glucan Branching Enzyme↗
PubMed1990

Allergens in Hymenoptera venom. XXII. Comparison of venoms from two species of imported fire ants, Solenopsis invicta and richteri.

Venoms were collected by electrical stimulation from the two major species of imported fire ants found in the United States, Solenopsis invicta (Sol i) and S. richteri (Sol r). Antigens similar to three of the four known Sol i venom proteins (I, II, III, and IV) were isolated from Sol r. The N-terminal amino acid sequences for the antigens III were identical; but those for the antigens II demonstrated only nine of 20 residues to be identical. Two monoclonal antibodies raised against Sol i II did not react to Sol r. No protein IV could be detected in Sol r by molecular weight, charge, or immunologically with either polyclonal mouse antibodies or five monoclonal antibodies. Both venoms were compared with a panel of 60 sera from Sol i-allergic individuals; mean bindings were similar with an r = 0.94 for linear regression. RAST inhibition was performed with 17 individual sera representing a variety of Sol i allergen specificities. Four sera were tested from patients resident in the Sol r endemic area and five sera from patients who experienced reactions to S. xyloni stings. All sera reacted comparably to both imported fire ant venoms. The two venoms appear to be allergenically similar, although antigen IV is absent from Sol r and the antigens II have significant sequence variation. Sol i venom appears to be sufficient for diagnostic purposes.

Allergens↗
PubMed1990

Emotional responses of athletes to injury.

Increased participation in sports is associated with increased related injuries. This study was conducted to identify the emotional responses of athletes to injury and to determine which responses might interfere with rehabilitation and necessitate psychologic or psychiatric intervention. In 72 patients, follow-up surveillance was continued from the time of injury until resumption of sports activity. Patients completed the Emotional Responses of Athletes to Injury Questionnaire and the Profile of Mood States (POMS) test, and significant differences were found when the POMS scales of depression and anger were compared with college norms. Mean POMS scores were compared (by multivariate analysis of variance) by sex, age, and severity of injury. No gender differences were found, and only for anger were age groups significantly different (younger athletes were most angered). Three severity-of-injury groups (based on the duration of time the athlete was unable to participate in sports) were also compared. The most seriously injured group experienced significantly more tension, depression, and anger and less vigor than college norms, a mood disturbance that lasted 1 month. Emotional disturbance can occur after a sports-related injury, and its prompt recognition may facilitate the athlete's optimal rehabilitation and a safe return to participation in sports.

Adolescent↗
PubMed1990

Topically active carbonic anhydrase inhibitors. 3. Benzofuran- and indole-2-sulfonamides.

Derivatives of benzofuran- and indole-2-sulfonamide were prepared for evaluation as topically active ocular hypotensive agents. These compounds were found to be excellent inhibitors of carbonic anhydrase and to lower intraocular pressure in a rabbit model of ocular hypertension. However, the development of these compounds for clinical use was precluded by the observation that they cause dermal sensitization in guinea pigs. A correlation between electrophilicity, as assessed by in vitro reactivity with reduced glutathione, and dermal sensitization potential was further documented.

Administration, Topical↗
PubMed1990

Purkinje cell simple spike activity during grasping and lifting objects of different textures and weights.

1. Three monkeys (2.5-3.5 kg) were trained to pinch an object between the thumb and forefinger and to lift it a vertical distance of 1.0-2.0 cm. Either the object weight (15, 65, or 115 g) or the surface texture (sand paper or polished metal) contacting the fingers could be varied. The object was equipped with a vertical position transducer, an accelerometer, and strain gauges that measured the grip force and the vertical load force. 2. In accordance with similar previously published studies on human subjects, it was found that monkeys appropriately scaled the grip forces according to the weight and coefficient of friction of the object. The grip force preceded the load force by 25 ms, and they both covaried with the changes in surface friction. 3. An analysis of electromyograms (EMGs) recorded intramuscularly from the muscles of the wrist and fingers including both flexors and extensors indicated that 26 muscles were active during pinching and lifting. Of these, 17 produced the maximum activity for the slippery surface and the greatest weight and the least activity with the roughest surface and lightest weight. 4. A total of 59 Purkinje cells and 123 unidentified units recorded from the paravermal and lateral cerebellar cortex were found to change their firing frequency during lifting the experimental object. 5. Increased discharge during the grasping and lifting was found for 56% (33/59) of the Purkinje cells and 80% (98/123) of the unidentified neurons, whereas 44% (26/59) of the Purkinje cells and 20% of the unidentified neurons decreased activity during the same period. 6. Significant modulations of the firing frequency with surface texture or object weight occurred for 59% (35/59) of the Purkinje cells and 67% (82/123) of the unidentified neurons. 7. One hundred and three Purkinje and unidentified neurons recorded in the paravermal and lateral region of the cerebellar cortex were examined for peripheral receptive fields, and of these, 43/103 (42%) responded exclusively to imposed displacements and tapping of muscles suggesting afferents originating from proprioceptors. A further 28/103 (27%) had exclusively cutaneous receptive fields on the hand that could be stimulated by brushing the skin lightly with a sable hair brush. Only six neurons demonstrated convergent cutaneous and proprioceptive receptive fields and no response to peripheral stimulation could be found for 26 neurons. No difference was found between the receptive fields of Purkinje cells and those of the unidentified neurons.(ABSTRACT TRUNCATED AT 400 WORDS)

Action Potentials↗
PubMed1990

The impact of gestational length on human milk selenium concentration and glutathione peroxidase activity.

Longitudinal changes in selenium (Se) and protein concentrations and glutathione peroxidase (GSH-Px) activity of milk collected from healthy mothers of term (n = 12), preterm (n = 10), and very preterm (n = 12) infants were assessed. All infants were size appropriate for gestational age. Milk samples representative of colostrum (d 3), transitional (d 7), and mature milk (d 21 and 42) were assayed. The content of Se in the colostrum secreted by mothers of preterm infants was significantly greater than the Se content of milk secreted by the same mothers at d 21 and 42 of lactation. Mothers of term and very preterm infants, however, produced colostrum with significantly higher levels of Se than milk produced at d 7 (p less than 0.05), d 21 (p less than 0.01), or d 42 (p less than 0.001). Significant differences between the protein concentrations measured in early lactation and in late lactation were evident in all maternal groups. Protein content did not differ significantly among groups at anytime during lactation. An age-related difference was detected in milk GSH-Px activities of mature milk (d 21). Mature milk produced by mothers of very preterm infants on d 21 of lactation contained significantly greater enzyme activity (p less than 0.05) than milk produced by mothers of term infants at the same stage of lactation. Activity of GSH-Px in milk from mothers of very preterm and preterm infants paralleled previously noted changes in long-chain polyunsaturated fatty acid content in human milk with the progression of lactation.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗
PubMed1990

Adrenal medullitis in type I diabetes.

To investigate whether cell-mediated immunity against the adrenal medulla occurs in type I diabetes (IDDM), we conducted a retrospective autopsy study of adrenal glands from IDDM and nondiabetic subjects using formalin-fixed tissue. Forty-four IDDM subjects, aged 4-67 yrs (mean +/- SD, 44.8 +/- 15.4) with a duration of IDDM from 0-55 yr (28.6 +/- 14.2), and 29 nondiabetic controls, aged 8-82 yr (51.8 +/- 18.6), were evaluated for a lymphocytic infiltrate using UCHL1, which recognizes a subpopulation of resting T-lymphocytes and most activated T-lymphocytes. Immunohistochemistry using antihuman B-cell antibody (L26) was also performed. Sections were scored for both lymphocytic infiltrates and fibrosis [none (0), small (1), moderate (2), or large (3)]. Blinded scoring was performed. A moderate to severe UCHL1 infiltrate was present in 9 of 44 (20%) IDDM, compared with 1 of 29 (3%) control subjects (P less than 0.04). Mild to severe fibrosis (score 1, 2, or 3) was present in 22 of 42 (52%) IDDM subjects compared with 4 of 25 (16%) control subjects (P = 0.003). Eight of 42 (19%) IDDM subjects had moderate to severe fibrosis (score 2 or 3) compared with 1 of 25 (4%) control subjects. Seventeen of 44 (39%) IDDM subjects had either a moderate to large cellular infiltrate or moderate to severe adrenal medullary fibrosis compared with 2 of 29 (7%) control subjects (P = 0.003). Staining of the adrenal medulla with L26 revealed a large cellular infiltrate in only one subject who was UCHL1 negative. Adrenal medullitis was observed in 20% of IDDM subjects, suggesting that the adrenal medulla may be another immunological target in IDDM.

Adolescent↗
PubMed1990

The psychological effects of sports injuries. Coping.

Epidemiological reports of sports injury confirm a high incidence of injuries occurring at all levels of sport participation, ranging in severity from cuts and bruises to spinal cord injury. The psychosocial dynamics accompanying sport injury should be known to ensure psychological recovery, an important aspect in rehabilitating the injured athlete. Earlier studies demonstrating psychological differences between athletes and nonathletes indicated the need for actual research on the athlete's postinjury response in lieu of accepting the hypothesis that the emotional responses of athletes to injury parallels existing (i.e. terminally ill) 'loss of health models'. Recent research has shown that injured athletes experience simultaneous mood disturbance and lowered self-esteem. Due to a paucity of research on the coping methods of injured athletes, studies involving the coping methods of several nonathletic patient populations were reviewed. These patients benefitted primarily from a concrete, problem-focused, behaviourally orientated programme which minimises uncertainty. This approach is theoretically ideal for injured athletes, congruent with the goal setting and performance outcome emphasis common to exercise and sport training programmes but to date the effectiveness of these strategies for injured athletes have not been fully examined. Therefore, until such research is available, these coping strategies (also used for performance enhancement) are provided as therapeutic guidelines for dealing with the emotional distress experienced by injured athletes. Individual responses of injured athletes varied from those who took injury in stride to those who required psychiatric intervention. This marked individual variation in response underscores the importance of neither assuming mood disturbance nor overlooking a serious emotional response in the injured athlete. Awareness of the emotional responses of athletes to injury and employment of appropriate coping strategies should facilitate optimal rehabilitation and return to sport.

Adaptation, Psychological↗
PubMed1990

Complement-fixing antibodies to sympathetic and parasympathetic tissues in IDDM. Autonomic brake index and heart-rate variation.

We describe herein complement-fixing anti-adrenal medullary (CF-ADM) and anti-sympathetic ganglia (CF-SG) antibodies in insulin-dependent diabetes mellitus (IDDM). This study describes complement-fixing anti-vagus (CF-V) nerve antibodies and their relationship to the cardiovascular autonomic brake index (a measure of transient decrease in heart rate during the 1st min after a tilt), and R-R interval variation with deep breathing. CF-V was detectable in 7 of 83 (8.4%) subjects with IDDM aged 1.5-65.5 yr (mean +/- SE 28.7 +/- 1.8 yr) and duration of diabetes 0-47 yr (11.8 +/- 1.4 yr). Seventy-six nondiabetic subjects (aged 10-65 yr) all had negative CF-V scores. CF-V scores correlated with CF-ADM (0-16 yr of IDDM, r = 0.61, P less than 0.0001) and CF-SG (r = 0.39, P less than 0.05). Seventy IDDM subjects (aged 28 +/- 5 yr, duration of diabetes 17 +/- 3 yr) without proteinuria or proliferative retinopathy were screened for CF-ADM, CF-SG, and CF-V antibodies. Five of 70 (7.1%) had CF-SG only (negative for CF-ADM and CF-V). Brake indices ranged from 14.7 to 51.3 (37.3 +/- 6.9). Three of 70 (4.2%) had CF-ADM only, with brake indices from 26.9 to 45.1 (32.9 +/- 6.1). Four of 70 (5.7%) had CF-V antibodies only, with brake indices of 12.7-17.3 (15.1 +/- 1.1). Subjects with CF-SG or CF-ADM (anti-sympathetic) had higher brake indices than subjects with CF-V (anti-parasympathetic) antibodies (P less than 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗