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Biomedical subjects

F Smith

Publications and source records attributed to F Smith.

At least 73 records · Page 4Linked to original sources

Recruitment for phase II of the Trials of Hypertension Prevention. Effective strategies and predictors of randomization. Trials of Hypertension Prevention (TOHP) Collaborative Research Group.

Phase II of the Trials of Hypertension Prevention is a multicenter, randomized, controlled trial designed to determine the efficacy of weight loss and reduction of sodium intake for lowering blood pressure and incidence of hypertension among persons with high-normal levels of blood pressure. The 2 x 2 factorial study design includes weight loss alone, restricted sodium intake alone, the combination of weight loss and sodium restriction, and a control group. Nine clinical centers used a variety of recruitment strategies to enroll 2382 participants over 17 months, which exceeded the sample size goal of 2250. Among randomized participants, 21% were minorities and 34% were women. Overall, direct mail generated the most randomized participants (73%), followed by community screening (12%) and media advertisement (11%). Referrals from community health care providers yielded few participants. Prescreening improved overall efficiency and reduced costs. Participants who were more likely to drop out voluntarily during the three-visit screening regimen tended to be younger, single, male, smokers, and less educated.

Adult↗

Evaluation of a collagen membrane with and without bone grafts in treating periodontal intrabony defects.

The aim of this study was to compare the clinical regenerative capacity of collagen membrane with and without demineralized freeze-dried bone allografts (DFDBA) in treating periodontal intrabony defects. Ten systemically healthy patients with similar bilateral periodontal defects were scheduled for surgery. Each patient had at least > or = 6 mm clinical probing depth and loss of attachment at selected sites. Baseline measurements included gingival index (GI), plaque index (PI), gingival recession (GR), clinical attachment level (CAL), probing depth (PD), and mobility. At the time of surgery, the defects were randomly assigned to either test (collagen membrane plus DFDBA) or control group (collagen membrane only). Stent to base of the defects, stent to crest bone, crest of bone to base of the defect, and width of the defects were recorded at the time of surgery and reentry. Eight patients returned after 6 months for reentry surgery. Statistical analysis with a paired t test was used to evaluate the treatment effect and comparison between test and control groups. In addition, a McNemar test was used to analyze the significance of GI, PI, and mobility at different times. The result of this study indicated that both the collagen plus DFDBA and the collagen alone treatment groups had a significant decrease of PD (3.4 +/- 0.4 and 3.2 +/- 0.4 mm), gain of CAL (2.3 +/- 0.5 and 2.0 +/- 0.4 mm), and defect fill (1.7 +/- 0.3 and 1.9 +/- 0.9 mm) (P < 0.05) when compared to the presurgery status. However, there was no significant difference in PD, AL, GR, defect fill, crestal bone resorption, GI, PI, or mobility between the test group and control group. No adverse tissue reaction, infection, or delayed wound healing was noted throughout the treatment in either group. This study suggests that the collagen membrane is well tolerated by the human tissues. Both treatments, either collagen membrane plus DFDBA or collagen membrane alone, promoted significant resolution of periodontal intrabony defects. The addition of a bone graft (DFDBA) with a collagen membrane appears to add no extra benefit to the collagen membrane treatment.

Adult↗

Compliance with an allergen immunotherapy regime.

BACKGROUND: Compliance with an allergy immunotherapy regimen is obviously the difference between a potentially successful or unsuccessful outcome. OBJECTIVE: The purpose of this study was to assess retrospectively compliance of patients receiving immunotherapy in a private allergy practice. METHODS: The study evaluated retrospectively patient compliance with prescribed allergy injections for a private practice in Atlanta, Georgia. Patients who ordered allergy extract material for their injection immunotherapy program during an 18-month period served as the index population for this study. For the purposes of this study, noncompliance was defined as stopping the allergy injection program without the approval of the prescribing physician. Part of this investigation was to determine whether there were compliance differences between those who received their allergy injections within the confines of the clinic and those who received their injections at outside physician offices. A 12-month period of review was considered adequate to monitor compliance because of the 12-month expiration date placed on the allergy extracts. RESULTS: There was a noncompliance rate of 10: 77% for those who received their injections within the clinic. This contrasted with the noncompliance rate in the remote population of 34.82%. The difference between these two groups was statistically significant (P < .01). There were no statistical differences with respect to sex or diagnostic category. Significant differences were found between age groups in those receiving injections within or outside the clinic. CONCLUSIONS: There is a much higher rate of noncompliance in those who receive their injections in facilities outside the allergist's office. This suggests that to ensure better compliance either individuals should either be encouraged to receive their injections at the allergist's office, or better communications should be established between the referring allergist and the nonallergy physicians who are administering the injections.

Adolescent↗

Pre-operative plasma levels of thrombin-antithrombin III complexes correlate with the development of venous thrombosis after major hip or knee surgery.

STUDY OBJECTIVE: To determine whether levels of thrombin-antithrombin III (TAT) in plasma, taken two weeks pre-operatively, predict the development of deep vein thrombosis (DVT) in patients undergoing major hip or knee surgery. DESIGN: Prospective cohort. SETTING: Tertiary-care referral centre, university-affiliated hospital. PATIENTS: Ninety eight consecutive patients undergoing elective hip or knee surgery. INTERVENTION: All eligible consenting patients were seen in a preoperative clinic two weeks prior to surgery and had blood taken for measurement of plasma TAT level. After surgery, they received a combination of unfractionated heparin 5000 Units 12-hourly subcutaneously, and antiembolism stockings (TEDS), as prophylaxis against DVT. Contrast venography was performed prior to discharge, and according to the results, patients were classified as having proximal (popliteal and/or more proximal) DVT (n = 12), calf DVT (n = 7) or no DVT (n = 79). MEASUREMENTS AND RESULTS: The mean TAT level was significantly higher in patients who developed DVT (5.7 micrograms/l) than in those who did not (4.1 micrograms/l), p = 0.035. Using cut-points of 3.5 and 5.5 micrograms/l for the TAT level, patients could be categorized as high, intermediate, and low risk for the development of DVT. The proportion of patients with TAT levels of > or = 3.5 micrograms/l who developed calf or proximal DVT was significantly higher than the proportion of patients with TAT levels of < 3.5 micrograms/l who developed calf or proximal DVT (p = 0.02). The proportion of patients with TAT levels > 5.5 micrograms/l who developed proximal DVT was significantly higher than the proportion of patients with TAT levels of < or = 5.5 micrograms/l who developed proximal DVT (p = 0.03). CONCLUSIONS: This study demonstrates that pre-operative TAT levels correlate with the risk of developing DVT after major orthopedic surgery. Further studies are needed to determine the reason(s) for this observation and whether rational recommendations about prophylaxis and screening for DVT can be made based on the results of a preoperative TAT level.

Adult↗

Direct peptide profiling by mass spectrometry of single identified neurons reveals complex neuropeptide-processing pattern.

A novel strategy combining peptide fingerprinting of single neurons by matrix-assisted laser desorption ionization mass spectrometry, molecular cloning, peptide chemistry, and electrospray ionization mass spectrometry was used to study the intricate processing pattern of a preprohormone expressed in identified neurons, the neuroendocrine light yellow cells (LYCs) of the gastropod mollusc, Lymnaea stagnalis. The cDNA encoding the precursor, named prepro-LYCP (LYCPs, light yellow cell peptides), predicts a straightforward processing into three peptides, LYCP I, II, and III, at conventional dibasic processing sites flanking the peptide domains on the precursor. However, matrix-assisted laser desorption ionization mass spectrometry of single LYCs revealed trimmed variant peptides derived from LYCP I and II. The variants were much more abundant than the intact peptides, indicating that LYCP I and II serve as intermediates in a peptide-processing sequence. Using the molecular masses of the peptides as markers to guide their isolation by well established purification methods, the structural identities of the peptides could be confirmed by amino acid sequencing. Furthermore, matrix-assisted laser desorption ionization mass spectrometry could detect colocalization of a novel peptide with the LYCPs.

Amino Acid Sequence↗

A comparison of subcutaneous low-molecular-weight heparin with warfarin sodium for prophylaxis against deep-vein thrombosis after hip or knee implantation.

BACKGROUND: Deep-vein thrombosis is a potentially life-threatening complication of total hip or knee replacement. There are few data on the effectiveness and safety of warfarin as compared with low-molecular-weight heparin as prophylaxis against this problem. METHODS: We therefore performed a randomized, double-blind trial in 1436 patients to evaluate the effectiveness and safety of low-molecular-weight heparin (given subcutaneously once daily) as compared with adjusted-dose warfarin to prevent venous thrombosis after hip or knee replacement. Treatment with the drugs was started postoperatively. The primary end point was deep-vein thrombosis as detected by contrast venography (performed a mean of 9.4 days after surgery in each group). RESULTS: Among the 1207 patients with interpretable venograms, 231 of 617 patients (37.4 percent) in the warfarin group and 185 of 590 patients (31.4 percent) in the low-molecular-weight-heparin group had deep-vein thrombosis (P = 0.03). The reduction in risk with low-molecular-weight heparin as compared with warfarin was 16 percent, and the absolute difference in the incidence of venous thrombosis was 6 percent in favor of low-molecular-weight heparin (95 percent confidence interval, 0.8 to 11.4 percent). The incidence of major bleeding was 1.2 percent (9 of 721 patients) in the warfarin group and 2.8 percent (20 of 715 patients) in the low-molecular-weight-heparin group (P = 0.04), and the absolute difference was 1.5 percent in favor of warfarin (95 percent confidence interval, 0.1 to 3.0 percent). CONCLUSIONS: Our data demonstrate that the small reduction in the incidence of venous thrombosis with low-molecular-weight heparin, as compared with warfarin, was offset by an increase in bleeding complications. Although the use of low-molecular-weight heparin is simpler, because it is administered subcutaneously without the need for monitoring, it may be more costly than warfarin. Warfarin is inexpensive, but the overall cost of its use is increased by the need to monitor the intensity of anticoagulation. At this time it is unclear which of these approaches is the most cost effective.

Administration, Oral↗

Patients as friends.

Explore the source record for details and available documents.

Attitude of Health Personnel↗

Selective effects of some 5-lipoxygenase inhibitors on synovial interleukin-1 (IL-1) production compared with IL-1 synthesis inhibitors.

To determine the role of 5-LO regulation of IL-1 in synovial tissues, we examined the effects of 5-LO inhibitors compared with standard IL-1 synthesis inhibitors on IL-1 production by human synovial tissue explants from patients with inflammatory arthropathies. MK886, L-656,224, PF-5901, and tepoxalin all inhibited IL-1 production in concentrations up to 10 microM, whereas other 5-LO inhibitors (ICI-211,965, zileuton), as well as IL-1 synthesis inhibitors (IX-207,887, tenidap), were inactive. LT products, thus regulate IL-1 production and inhibition thereof is one strategy for inhibiting this cytokine.

Arthritis↗

Selective T-cell-receptor gene usage in allorecognition and graft-versus-host disease.

Immune recognition of foreign HLA molecules is initiated by T cell recognition mediated by alloreactive T cell receptor (TCR) molecules. We analyzed the diversity of TCR expression in the clinical setting of allorecognition in a patient with acute graft-versus-host disease following bone marrow transplantation. Nearly 200 TCR transcripts from peripheral blood lymphocytes were cloned and sequenced at two time points during GVHD. HLA genes in the transplant donor and the recipient were mismatched for a very specific HLA-DR subtype: HLA-DRB1 genes in the donor (DR4/Dw4) and the recipient (DR4/Dw14) encode HLA molecules that differ at only two amino acids, providing a very restricted target for allorecognition. We also studied TCR genes from five T cell clones derived in vitro from mixed lymphocyte cultures between Dw4-positive responder and Dw14-positive stimulator cells. Comparisons of the derived TCR sequences implicate nonrandom patterns of TCR selection both in vivo and in vitro.

Acute Disease↗

Study of left and right ventricular function in Romano-Ward syndrome.

OBJECTIVE: To examine left and right ventricular contraction in Romano-Ward syndrome: does abnormal myocardium affect the predisposition to arrhythmia? DESIGN: Tomographic radionuclide ventriculography was performed after the red blood cells were labelled conventionally with stannous pyrophosphate and technetium-99m. SETTING: Department of Nuclear Medicine, Aberdeen Royal Infirmary. PATIENTS: Eight subjects from two families known to have Romano-Ward syndrome, four of whom (two from each family) had had symptoms. RESULTS: The five subjects from family 1 had normal left ventricular contraction; two had subtle abnormalities of right ventricular phase. in family 2 all three subjects had abnormal left ventricular contraction (reduced amplitude in three, abnormal phase in two). All had subtle abnormalities of right ventricular phase. CONCLUSION: Abnormal right or left ventricular myocardium may be partly or wholly responsible for the repolarisation changes seen on the electrocardiogram of these families or may act as an ectopic focus to start ventricular tachycardias in a susceptible heart.

Adult↗

Evaluation of ferric oxalate as an agent for use during surgery to prevent post-operative root hypersensitivity.

The aim of this study was to evaluate the effectiveness of a 6% ferric oxalate solution applied during periodontal surgery to prevent post-operative tooth hypersensitivity. Twenty-five adult patients with similar bilateral periodontal defects participated in this study. Data were collected at baseline (1 week prior to surgery) and 1, 2, 4, and 6 weeks following surgery. Sensitivity level was determined using the visual analog scale (VAS) with the following stimuli: 1) mechanical stimulation with a No. 23 dental explorer; 2) water at 50 degrees C; 3) ice; and 4) electric pulp tester (EPT). Teeth were randomly assigned to either test (6% ferric oxalate in 0.9% saline) or control (0.9% saline) groups. Solutions were applied to the exposed root surfaces for 1 minute during surgery. Data were analyzed by repeated measures ANOVA, paired t-test, and Pearson's correlation test. Results from this study demonstrated statistically significant reduction in the responses to thermal stimuli, especially cold, between groups treated with ferric oxalate as compared to those treated with saline. For the cold test the difference increased with time from baseline to 6 weeks. Statistically significant (P < 0.05) differences in sensitivity to heat between groups were also observed, but only at 2 and 4 weeks following surgery. There were no differences at any time period between the test and control groups when tactile or EPT techniques were used. In addition, there was no correlation between sensitivity and other clinical parameters. It was concluded from this study that 6% ferric oxalate was effective in reducing post-surgical cold sensitivity when applied during periodontal surgical procedures.

Adult↗

Helicobacter pylori prevalence in acquired immunodeficiency syndrome.

Helicobacter pylori is consistently reported with high prevalence in HIV-negative patients with chronic gastritis and active ulcer disease. This study is an evaluation of the prevalence of H. pylori in AIDS patients, and the association with chronic gastritis, erosions, and ulcer disease. Seventy-three AIDS patients referred for the evaluation of gastrointestinal symptoms underwent upper endoscopy and antral gastric biopsy. Histologic gastritis was diagnosed and degree of activity graded on hematoxylin-eosin stain. H. pylori organisms were identified by acridine orange stain. A single pathologist evaluated the biopsy specimens. H. pylori was found in 15% (11 of 73) of AIDS patients. Histologic chronic active gastritis was evident in 94.5% (69 of 73) of the study group. H. pylori was identified in 15.9% (11 of 69) of biopsy specimens with histologic chronic active gastritis. The organism was more common in biopsy specimens with a higher grade of activity in the chronic gastritis. Endoscopic erosions or ulcers were noted in 11 patients (seven gastric, four duodenal). H. pylori was present in 18% (2 of 11) of AIDS patients with erosions or ulcers. The prevalence of H. pylori in AIDS patients with histologic chronic active gastritis is much lower than the prevalence previously reported for HIV-negative patients with similar pathology. The low prevalence observed does not implicate H. pylori as the causal agent in most chronic active gastritis in the AIDS population. Impaired acid secretion may reduce colonization of gastric mucosa and explain the low rate of H. pylori observed.

Acquired Immunodeficiency Syndrome↗

Pleural liposarcoma presenting with respiratory distress and suspected diaphragmatic hernia.

A young woman with a history of diaphragmatic hernia presented to the hospital in respiratory distress and in premature labor. Her admission chest roentgenogram showed opacification of the left hemithorax, and her arterial blood gas analysis revealed hypoxemia. Emergency cesarean section and exploratory left thoracotomy were carried out; a large tumor occupied the left side of the chest, and pneumonectomy was performed. No diaphragmatic hernia was present. A pathologic diagnosis of primary liposarcoma was made.

Adult↗

Relationship between determinants of oxygen delivery and respiratory abnormalities in preterm infants with anemia.

To study the relationship between anemia and breathing abnormalities in preterm infants, we measured oxygen supply and demand in two groups of anemic infants less than or equal to 32 weeks of gestational age. Six-second apnea density was less than 1% in one group and greater than or equal to 5% in the other. There were no differences in hemoglobin concentration, available oxygen, oxygen consumption, or Doppler-determined cardiac output between the two groups of infants. Furthermore, in anemic preterm infants with apnea density greater than or equal to 5%, reductions in 6-second apnea density were similar after erythrocyte transfusion (mean +/- SEM: from 8.6% +/- 1.1% to 4.7% +/- 0.7%) or after an isovolemic infusion of 5% albumin (from 9.0% +/- 1.4% to 4.7% +/- 0.7%). These results show no relationship between measures of oxygen delivery and respiratory irregularities, and indicate that volume expansion may play a role in ameliorating the pneumocardiogram abnormalities.

Anemia↗

Focal ventricular thinning caused by indomethacin in the late phase of coxsackievirus B4 murine myocarditis.

Indomethacin has been shown to increase virus titers and to worsen cardiac injury in the acute phase of coxsackievirus B4 murine myocarditis. The authors evaluated the effects of indomethacin on the histopathologic changes in a later phase of this disease after virus clearance. Two-day old CD1 mice were infected with coxsackievirus B4. Ten days later, surviving animals were randomized to receive indomethacin or saline intraperitoneally for 10 days. They were then euthanatized, and their hearts were examined for the presence of inflammation, necrosis, scarring, and focal thinning. Mortality was slightly higher among treated animals (7/15 versus 2/12, p = 0.3). The index of inflammation (0.6 +/- 0.5 versus 0.7 +/- 0.5) necrosis and scarring (0.4 +/- 0.5 versus 0.3 +/- 0.5) among treated and control animals, respectively, was not significantly different, but the size of involved myocardium (149742 +/- 201982 versus 35300 +/- 45413 microns2) was remarkably larger (p less than 0.05), and focal ventricular thinning (5/12 versus 0/10, p = 0.03) was encountered among indomethacin recipients exclusively. These findings indicate that indomethacin treatment in the late phase of coxsackievirus B4 myocarditis enhances myocardial damage and increases the incidence of focal ventricular thinning.

Animals↗