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Biomedical subjects

D A Grainger

Publications and source records attributed to D A Grainger.

16 recordsLinked to original sources
PubMed1991

Effect of acute physiological elevations of insulin on circulating androgen levels in nonobese women.

Extreme pharmacological elevation of the circulating insulin level acutely lowers dehydroepiandrosterone sulfate (DHEAS) levels. To assess whether more physiological elevations in plasma insulin (due to exogenous infusion or endogenous secretion) would have similar effects, we examined the levels of DHEAS, androstenedione, testosterone, and free testosterone before and after euglycemic hyperinsulinemic and hyperglycemic hyperinsulinemic clamp studies. Studies were performed in women within 20% of ideal body weight after an overnight fast. Androgen levels were measured before and at the conclusion of studies in which either insulin was infused exogenously at 1 mU/kg.min or endogenous insulin secretion was stimulated for 2 h by elevation of the plasma glucose concentration by 125 mg/dL above basal levels by an exogenous glucose infusion. Basal plasma DHEAS (6.2 +/- 0.5 mumol/L) declined to 5.2 +/- 0.4 mumol/L (P less than 0.001) during the euglycemic insulin clamp, without any significant change in testosterone, free testosterone, or androstenedione. During the hyperglycemic clamp, DHEAS fell from 6.7 +/- 0.5 to 5.1 +/- 0.4 mumol/L (P less than 0.001) in response to endogenous hyperinsulinemia; plasma testosterone, free testosterone, and androstenedione did not change significantly. There was no correlation between the elevation in plasma insulin concentration and the fall in DHEAS during either the euglycemic or hyperglycemic clamps. However, the magnitude of fall of DHEAS was directly correlated with the initial DHEAS level in both the euglycemic (r = 0.51; P less than 0.05) and hyperglycemic (r = 0.75; P less than 0.01) studies. This association of hyperinsulinemia with a reduction of circulating levels of DHEAS, but not other C-19 steroids (e.g. testosterone and androstenedione) may reflect differential mechanisms by which DHEAS levels are regulated and suggests that insulin either inhibits its biosynthesis and/or secretion, or enhances its MCR.

Androgens↗
PubMed1991

Ovarian surgery on the rabbit. Effect of cortex closure on adhesion formation and ovarian function.

Surgical reapproximation of serosal surfaces in an attempt to reduce adhesiogenesis remains a controversial issue. For the reproductive gynecologist, this tenet is especially appropriate to the ovarian cortical surface. Using a rabbit model (n = 22), an ovarian unipolar cautery incision was created, and surgical closure versus nonclosure was evaluated. Closure with continuous 6-0 polyglactin resulted in a significant increase in the degree of ovarian adhesion envelopment versus nonclosure (1.8 +/- 0.2 vs. 0.9 +/- 0.2, P less than .01). Surgical closure also resulted in a significant increase in the vascularity of the adhesions (P less than .05). Despite the increase in adhesion formation, ovarian function, as determined by the mean number of corpora lutea, pregnancies and the nidation index, was not different in sutured ovaries, unsutured ovaries or nonsurgically treated controls.

Animals↗
PubMed1991

Laparoscopic clips. Evaluation of absorbable and titanium with regard to hemostasis and tissue reactivity.

Advanced laparoscopic techniques require laparoscopic means of providing hemostasis. We tested the hemostatic ability of laparoscopic surgical clips and their tissue reactivity as assessed by adhesion formation in an animal model. Twenty-six New Zealand white rabbits were randomized at laparotomy to one of three treatment groups: titanium surgical clips, absorbable surgical clips (both applied with a laparoscopic clip applicator) and chromic sutures of equal mass. Either the right fallopian tube was transected, with clips or sutures applied proximally and distally to control bleeding, or the clips or sutures were applied 5 mm apart and the tube transected. A clip or suture of the same material was placed on the midportion of the left fallopian tube. Necropsy was performed at 42 days, and each clip/suture site was scored for adhesions. All the materials were easily applied and effective in achieving hemostasis. The adhesion scores tended to be lower with the absorbable clips; however, there were no statistically significant differences between the groups. Laparoscopic clips are effective in providing hemostasis, are easily applied and cause no more adhesion formation than do conventional suture materials.

Animals↗
PubMed1990

Ureteral injuries at laparoscopy: insights into diagnosis, management, and prevention.

The increasing use of laparoscopy as a therapeutic method mandates a reappraisal of the risks involved. Complications frequently described include injuries to the large and small bowels, bladder, and blood vessels. The world literature reports only eight cases of ureteral injury at laparoscopy. In this report, we present five additional cases of ureteral injury occurring at laparoscopy, in addition to a summary of those previously reported. Patients tend to present in the early postoperative period (48-72 hours) with low back pain, abdominal pain, leukocytosis, and peritonitis. The diagnosis should be made by intravenous pyelography; if possible, the injury should be stented by either the retrograde or percutaneous route. The injuries, except for one apparent trocar injury, involved the use of electrocoagulation, both unipolar and bipolar. The injuries occurred most commonly near the uterosacral ligaments. In 38% (five of 13) of the cases, the laparoscopy was performed for treatment of endometriosis. Three of the 13 patients eventually lost renal function of the affected side; two of these underwent a nephrectomy. Because visualization of the ureter near the cervix at the time of laparoscopy is difficult, especially in the presence of disease, laparoscopic procedures in this area must be carried out with caution.

Adult↗
PubMed1989

Hysteroscopic management of uterine bleeding.

Hysteroscopy provides a means of accurately diagnosing and treating most forms of abnormal uterine bleeding. Submucous myomas and endometrial polyps may be easily removed with the resectoscope. If the myomas are large, pre-treatment with GnRH agonists will shrink the tumours, and facilitate hysteroscopic removal. One third of patients undergoing hysteroscopic myomectomy will have recurrent symptoms that require intervention. In the absence of malignancy, and in patients not desiring fertility, persistent dysfunctional uterine bleeding may be treated by endometrial ablation. These patients should be pre-treated with either danazol or GnRH agonists. Success with these techniques approaches 85%, but information about the long-term outcome for the majority of the reported cases is not available. Complications include uterine perforation and damage of intra-abdominal structures, fluid and electrolyte imbalance including pulmonary oedema, and anaphylactic reactions to certain distention media (32% dextran 70). These procedures provide the gynaecologist with an effective means of treating abnormal uterine bleeding without the attendant morbidity of a hysterectomy.

Female↗
PubMed1989

Endometriosis-associated infertility. Treatment options.

Formulating a treatment plan for infertility associated with endometriosis is difficult due to the lack of a cause-and-effect relationship between the disease and infertility. Several molecular and cellular mechanisms have been postulated as playing roles in endometriosis-associated infertility; they are reviewed here. Several medical and surgical treatment options are discussed, including danocrine, medroxyprogesterone acetate and gonadotropin releasing hormone agonists. A combined medical and surgical approach and occasional expectant management remain the treatments of choice.

Endometriosis↗
PubMed1989

Pelvic trophoblastic implants after laparoscopic removal of a tubal pregnancy.

Laparoscopic removal of ectopic gestations is becoming increasingly popular. We present a case in which an early, unruptured ampullary ectopic pregnancy was identified clinically, removed during laparoscopy, and subsequently confirmed by pathology. The patient later presented with pain and with rising titers of beta-hCG. Laparotomy demonstrated multiple pelvic implants of trophoblastic tissue.

Adult↗
PubMed1978

The viability of microorganisms in carious lesions five years after covering with a fissure sealant.

Carious lesions that were covered with a pit and fissure sealant for five years yielded bacterial cultures that were predominantly negative. Sixteen of 18 test sites judged to have active caries in 1972 were found inactive in 1977; ten of 12 sites suspected to have caries in 1972 were deemed to have inactive caries in 1977. Sealant treatment resulted in an apparent 89% reversal from a caries-active to a caries-inactive state. These data confirm and extend previous observations that a limited number of cultivable organisms persist in some lesions but their numbers are few, and they do not appear capable of continuing the destruction of tooth structure.

Acid Etching, Dental↗
PubMed1977

Triplet state energy transfer in several proteins.

Energy transfer between excited triplet states of aromatic amino acid residues was observed at 1.4 degrees K. The distance necessary for energy transfer between monomeric tyrosine and tryptophan residues was determined to be roughly 63 A. Total phosphorescence decay rate constants for several proteins were determined while emission corresponding to tyrosine and tryptophan residues was monitored. The observed decay rate constants are interpreted in terms of intramolecular interactions of the polypeptide residues.

Energy Transfer↗
PubMed1977

Four-year clinical evaluation of a pit and fissure sealant.

The clinical retention of a single application of a pit and fissure sealant was evaluated on the teeth of children to determine the influence that this protective coating, or its loss, would have on caries activity during a four-year period. The sealant was fully retained on 50% of all paired permanent teeth at 48 months. Of the 689 pit regions that retained the sealant, 95% were rated as having severe loss of substance, only 5% as slight loss, and none with no loss of substance. It also was found that 53% of all paired permanent control teeth judged cariesfree at the baseline examination were found to be carious, whereas only 30% of the treated teeth examined were carious. The corresponding relative reduction in caries rates was, therefore, 43%. The actual number of teeth estimated to be saved by the sealant treatment at 48 months, as measured by net gain per 100 teeth treated, was 23. The net gain per child was estimated as 2.7 teeth saved from caries (full mouth), with a positive treatment benefit in 69% of the children. When the sealant remained intact, there was a pronounced reduction in caries initiation--the percent effectiveness being 84%.

Adolescent↗
PubMed1977

The gamble.

Explore the source record for details and available documents.

Dentistry, Operative↗
PubMed1976

Two-year clinical evaluation of a pit and fissure sealant. Part II. Caries initiation and progression.

For the study, 479 paired permanent teeth and 20 paired deciduous teeth were coated under controlled clinical conditions with Nuva-Seal. A red dye was added to assist in placement and subsequent evaluation over a two-year period. Eighty-four children (ages 10 to 14) participated in the study. Caries was evaluated 3, 6, 12, and 24 months later with the same rating scale used at the baseline examination (0, caries free, to 4, severe caries), except when the sealant was found completely present and intact; then caries evaluation was limited to visual inspection through the sealant. The caries rate for control teeth was 6.9% at 3 months, 16.1% at 6 months, 26.4% at 12 months, and 37.6% at 24 months. Corresponding percent effectiveness figures for the sealant were 63.6%, 66.6%, 61.7%, and 54.6%, respectively. At 24 months, effectiveness rates for all types of teeth were at least 52% with the exception of the maxillary second molars (only 27% sealant effectiveness). Overall, caries protection as reflected by percent effectiveness was higher for mandibular teeth and premolars than for maxillary teeth and molars. There was significant effect on the incidence of dental caries when the sealant remained completely intact. Percentage effectiveness rates in this case were 90.7% at 12 months and 90.9% at 24 months. There was little gain or loss in caries protection when the sealant was partially or completely missing. Twenty-four percent of the children had a positive net gain or treatment effect at three months. This increased to 52% at 6 months, 62% at 12 months, and 70% at 24 months. With the use of half-mouth caries rates, the corresponding figures for positive treatment effects were slightly higher (30%, 64%, 70%, and 80% respectively).

Adolescent↗
PubMed1976

A new journal.

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Dentistry, Operative↗
PubMedDate not supplied

Evaluation of instructional materials for teaching psychomotor skills.

An investigation was conducted to determine the effectiveness of self-instructional materials for a cavity preparation procedure using two types of dental auxiliaries under assisted and unassisted instructional conditions. Results showed significant pretest to posttest performance gains, with the instruction proving equally effective across both types of auxiliaries and instructional conditions.

Dental Amalgam↗