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Biomedical subjects

C Sutton

Publications and source records attributed to C Sutton.

At least 55 records · Page 3Linked to original sources
PubMed1992

Effects of design geometry of intravascular endoprostheses on stenosis rate in normal rabbits.

To investigate the effects of gaps between the individual wire coils of a shape memory Nitinol alloy intravascular endoprosthesis, 20 stents with and without gaps were implanted transluminally into the infrarenal abdominal aortas of 10 normal rabbits after balloon angioplasty. Digital subtraction angiography (DSA) was done at 4, 12, 16, 20, and 24 weeks after stent implantation to examine the stenosis rate and major side branch patency. Stenosis rate within stents with gaps were significantly lower than those without gaps: 8.1 +/- 5.0% versus 15.0 +/- 6.8% at 12 weeks, 13.6 +/- 6.0% versus 26.0 +/- 9.4% at 24 weeks by DSA, p greater than 0.005 and p less than 0.01 respectively. The maximum and mean neointimal thickness measured histologically at the time of animal death correlated significantly to the narrowest diameter obtained from the DSA studies, (r = 0.84 and r = 0.79, respectively, p less than 0.01). Greater hyperplasia of the neointima was evident in the stented arterial segments with stents without gaps compared with those with gaps (83 +/- 22 versus 187 +/- 46 microns mean thickness, p less than 0.001). The patency rate of the side branches in the stented arterial segment was significantly (p less than 0.05) higher in stents having gaps. These results suggest that the placement of gaps between wire pitches reduced the neointimal thickness within stents and prevented the obstruction of arterial side branches.

Angioplasty, Balloon↗
PubMed1992

Forecasting the extent of the HIV/AIDS epidemic.

This paper has a dual objective: (1) to describe the current status of the structure of a newly developed model system to generate a wide span of U.S. HIV/AIDS estimates; and (2) to implement that system through the development of a dataset of HIV/AIDS incidence and prevalence, by stage, in the U.S. for a range of past and future years. There are many uncertainties regarding the anticipated effects of HIV/AIDS; examination of many of these effects indicates multiple societal difficulties. The characteristic of AIDS-growth is that of a long-delayed but inexorable disabling morbidity "taking off" in 1991-1992 from an HIV population widely thought to be 1.0-1.5 million spread throughout the Nation. Although widely dispersed, its impact, even at this early stage of growth, is to endanger the health and social support systems of our urban centers. The spread of AIDS cases into the smaller cities and rural counties indicates that those problems will not be limited to our major cities. This paper provides new and purposely pessimistic estimates of the levels of prevalence and incidence of HIV/AIDS for future years, based on U.S. AIDS cases reported. Although these numbers are essentially upper bounds, their values are consistent with the upper sides of some recent broad band projections released in early Summer 1989 by the U.S. Government Accounting Office (GAO). However, our estimation has generated data within a more proscribed range. A first set of forecasts has been provided to the State of Virginia's Department of Health for their use in statewide resource planning. The United States and the world face a severe HIV pandemic in the coming decade. The certainty of the threat is acknowledged by all of the major private and public medical authorities and institutions. Yet, to date, no official projection of the emergence, the level, and the sweep of the epidemic has been accepted by the medical community. And, there is certainly little agreement on the impact on the delivery of health care services in the United States and Canada, as well as throughout the world. On 26 June 1989, the U.S. GAO released a report that concluded, in part, that the Federal government's official data [e.g. from the Centers for Disease Control's (CDC) Morbidity and Mortality Weekly Report (MMWR) of 12 May 1989] were greatly understating the epidemic's extent. Specifically, the CDC's estimate of 185,000-320,000 (cumulative) cases of AIDS expected to be reported by the end of 1991 contrasted with GAO's estimate of 300,000-480,000.(ABSTRACT TRUNCATED AT 400 WORDS)

Acquired Immunodeficiency Syndrome↗
PubMed1992

The aftermath of youth suicide--providing postvention services for the school and community.

Suicide is one of the leading causes of death in adolescence. Due to the risk of contagion and maladaptive coping responses in the aftermath of suicide, clinicians have responded by developing postvention services. Based on a considerable amount of experience in this field, target groups of individuals have been identified to receive such assistance. These groups include school administrators, staff, students, families, and community members at large. In addition, it has become clear that the local media response to suicide is of critical importance, and that school administrators and local mental health officials should work effectively with reporters so that news stories do not contribute to suicide contagion.

Adaptation, Psychological↗
PubMed1992

Operative laparoscopy.

Minimally invasive surgery is going through a rapid phase of evolution and over a relatively short time we have witnessed progress from simple ablative procedures such as the division of adhesions and destruction of endometriosis to far more complex operations such as laparoscopic myomectomy, hysterectomy, and, perhaps the hardest of all, cul-de-sac dissection and resection of bowel involved in dense fibrotic endometriosis. Some of these newer procedures reach the very limits of technical virtuosity and are extremely time consuming and will need careful appraisal before their true place in clinical gynecology is established.

Endometriosis↗
PubMed1991

Purification of recombinant human prostromelysin. Studies on heat activation to give high-Mr and low-Mr active forms, and a comparison of recombinant with natural stromelysin activities.

Recombinant human prostromelysin was purified in a single step using Procion Red-Sepharose chromatography. The purified prostromelysin was self-activated to high-Mr (45,000) and low-Mr (28,000) forms by incubation at 55 degrees C without the addition of extraneous activators. The two forms of stromelysin were subsequently separated, again using Procion Red-Sepharose. Both of the heat-activated recombinant forms demonstrated similar specific activities (for the macromolecular substrates casein, gelatin, elastin, proteoglycan and type IV collagen) when compared with either heat- or trypsin-activated natural stromelysin. The heat-activated recombinant stromelysins both showed similar abilities to potentiate activation of human procollagenase when compared with trypsin-activated natural stromelysin.

Amino Acid Sequence↗
PubMed1991

Purification and characterization of Ku-2, an octamer-binding protein related to the autoantigen Ku.

The octamer motif (ATTTGCAT) is an important regulatory element in eukaryotic gene expression. A previously unidentified protein that recognizes this motif has been isolated from the human B cell line, Daudi. The protein, which we term Ku-2, bears a close resemblance to the DNA-binding autoantigen Ku. Like Ku, it is a heterodimer with subunits of 83 and 72 kDa; antisera raised against either subunit of Ku cross-react with Ku-2. Two peptides have been sequenced and show a strong similarity to regions in the corresponding subunits of Ku. The sequences are not identical, however, suggesting that Ku-2 may be a B cell homologue of Ku. Both Ku and Ku-2 bind to the termini of DNA duplexes, but Ku-2 also binds to an internal octamer motif. It is not known whether Ku shares the latter property or whether the octamer binding is a consequence of sequence differences between the two proteins. Ku-2 does not react with antisera against the POU domain of the octamer-binding protein Oct-2, indicating that the DNA binding domains of the two proteins are dissimilar despite the ability of both to bind to the octamer motif. We discuss the evidence for the existence of a family of octamer-binding proteins related to Ku.

Amino Acid Sequence↗
PubMed1991

The V3 loops of the HIV-1 and HIV-2 surface glycoproteins contain proteolytic cleavage sites: a possible function in viral fusion?

Located close to the crown of the V3 type-specific neutralization loop of the human immunodeficiency virus type 1 (HIV-1) (IIIB) SU glycoprotein gp120, are several potential sites that should be susceptible to proteolytic cleavage by enzymes of trypsinlike or chymotrypsinlike specificity, or by aspartic proteinases. The linkages potentially sensitive to chymotryptic/aspartic proteinase cleavage are retained also within the equivalent domain of HIV-2 (ROD) gp105. We show that thrombin and tryptase cleave HIV-1 gp120 specifically at the tryptic site (GPGR decreases AFVT), and that cathepsin E, an endosomal aspartic proteinase, cleaves at the chymotrypsinlike site (GPGRAF decreases VT). HIV-2 gp105 is also cut by cathepsin E at a site (QIML decreases MSGH) in its V3 loop. Cleavage of HIV-1 gp120 by thrombin is enhanced by sCD4 binding, but is prevented by transient exposure of gp120 to nonionic detergent. Thrombin treatment of HIV-1 gp120 destroys the binding sites for some neutralizing monoclonal antibodies (MAbs) on the V3 loop, but does not affect the affinity of gp120 for sCD4. Conversely, binding of neutralizing MAbs to the HIV-1 V3 loop prior to addition of thrombin or cathepsin E blocks the cleavage reactions, and the binding of some HIV-positive sera to gp120 blocks thrombin cleavage. Analysis of published sequences suggests that all HIV-1, HIV-2, and simian immunovirus (SIV) isolates contain potential proteolytic cleavage sites at similar positions in their V3 loops or equivalent domains. We suggest that cleavage of the V3 loop by a cell surface or endosomal proteinase occurs during the HIV-cell fusion reaction, and that neutralizing antibodies directed against the V3 loop might act by inhibition of this reaction.

Amino Acid Sequence↗
PubMed1990

Laser laparoscopic adhesiolysis.

Carbon dioxide laser laparoscopy offers a safe, effective, and relatively easy means of performing intraabdominal adhesiolysis. Sixty-five patients suffering from chronic lower abdominal pain have undergone laser laparoscopic adhesiolysis during the past 6 years. Fifty-three patients (84%) experienced symptomatic relief. The controversial association between abdominal pain and intraabdominal adhesions can be resolved only by performing a controlled prospective laser laparoscopic adhesiolysis study.

Abdominal Pain↗
PubMed1990

Mutilating palmoplantar keratoderma with periorificial keratotic plaques (Olmsted's syndrome).

We report the case of a boy, now aged 4 years, with a progressive, painful and disabling palmoplantar keratoderma, associated with well-defined hyperkeratotic plaques around the mouth and nostrils. His mother has an identical palmoplantar keratoderma. The palmoplantar keratoderma failed to improve with etretinate, but considerable benefit resulted from full-thickness excision of the skin of both palms, followed by skin grafting. We believe that he has a distinctive but extremely rare form of hereditary palmoplantar keratoderma, first described by Olmsted.

Child, Preschool↗
PubMed1990

Laser laparoscopy in the treatment of endometriosis. A 5-year study.

The carbon-dioxide laser used laparoscopically provides a precise and virtually bloodless technique for the vaporization of endometriotic implants in the pelvis. The technique has been used at St Luke's Hospital, Guildford, for the past 6 years and this report presents 228 consecutive patients with endometriosis treated during the 5 years between 1982 and 1987 and followed up for between 1 and 6 years. Pain was improved in 70% and 80% of the 56 infertile patients with endometriosis as the only identifiable abnormality conceived. Of the 54 pregnancies, only 37 (69%) had a successful outcome, reflecting the high pregnancy failure rate found in women with endometriosis. Hospital stay was relatively short and complications were few and usually minor and there was no injury or morbidity caused by laser energy. The main advantage of laser laparoscopy in endometriosis is that patients may be treated at the time of diagnosis with less need for medication and no delay before conception is attempted.

Adolescent↗
PubMed1989

Purification and sequencing of glycosylation variants of BSF-1, as a MAF, from the EL-4 leukaemia cell line.

Macrophage activation activity was characterized from a PMA-induced subclone of the murine EL-4 leukaemic cell line. The MAF was purified from the cell line culture supernatant by concentration, CM-Sepharose and lentil lectin Sepharose chromatography, AcA 54 gel filtration, Mono Q FPLC and reverse phase HPLC. Four protein bands of different abundance were observed on SDS-PAGE with molecular weights of 17,500 to 21,000 Da. Three of the four proteins were sequenced from the N-terminal and shared homology with the published sequence of BSF-1. Variation of the molecular weight due to glycosylation was demonstrated by N-glycanase treatment, all four proteins gave a band of 14,200 Da after deglycosylation. Both glycosylated and deglycosylated forms of BSF-1 were equally active in the MAF assay. A monoclonal antibody to BSF-1 neutralized 80% of the activity from crude culture supernatants in the MAF assay. These studies have indicated that BSF-1 is the major, if not the only, MAF activity from this particular subline of the murine EL-4 leukaemic cell line.

Amino Acid Sequence↗
PubMed1989

Multiple myocardial infarctions associated with atheromatous emboli after PTCA of saphenous vein grafts. A clinicopathologic correlation.

Percutaneous transluminal coronary angioplasty (PTCA) of stenotic saphenous vein grafts is less invasive than repeat coronary bypass grafting; however, this procedure is complicated by atheromatous embolization in 2.5%-3.0% of cases, an incidence significantly higher than in angioplasty of native coronary vessels. We reviewed the cases of 98 patients who underwent elective saphenous vein graft angioplasty at our institution. Five patients (5.1%) had non-Q-wave myocardial infarctions after the procedure, documented by elevated serum creatine kinase. In four, atheroembolism was suspected during the procedure. Two patients died, and autopsy showed that both had multiple atherosclerotic emboli to the distal epicardial coronary artery supplied by the vein graft. In addition, multiple infarcts of varying age, some clearly antedating the angioplasty procedure, were identified. These findings suggest that both ongoing, recurrent atheroembolism as well as angioplasty-related embolism may occur in older vein grafts.

Aged↗
PubMed1988

Dietary intake of calcium and postmenopausal bone loss.

The use of calcium supplements to prevent postmenopausal bone loss and hence osteoporosis is widespread, but the evidence for their efficacy, either alone or in combination with other treatments, is contradictory. Skeletal measurements and dietary intake of calcium were determined in 59 healthy postmenopausal women, most of whom were within five years of the menopause. No correlation was found between current intake of calcium and either total calcium in the body or the density of trabecular or cortical bone in the forearm or vertebral trabecular bone. Dietary intake of calcium did not influence the rate of postmenopausal bone loss in the 54 women who completed 12 months of active or placebo treatment. Even when extremes of calcium intake were examined no difference was found in bone measurements between the women with the highest and lowest intakes. The results of this study suggest that the bone density of women in the early menopause is not influenced by current dietary intake of calcium.

Adult↗
PubMed1988

Biological performance of TiNi shape memory alloy vascular ring prostheses: a two year study.

A method was developed for the noninvasive insertion of a vascular ring prostheses aimed at preserving arterial patency and preventing restenosis following angioplasty. Using a specially designed 7F catheter 22 nitinol (TiNi) wire prostheses (I.D. 5 mm; 0.25 mm thickness) were torsion reduced in diameter and inserted under fluoroscopy into both carotid (n = 2) and iliac-femoral arteries (n = 20) of dogs. Aspirin (650 mg BID) and Persantin (200 mg BID) were given for only 30 days postoperatively. Angiography of all rings at 1, 6, 12 months exhibited excellent biocompatibility and long term patency 91% (20/22) as reported in Trans ASAIO 32:30, 1986. Four rings inserted in the right and left common iliac arteries and femoral artery were followed for up to 2 years and exhibited 100% patency. Angiography demonstrated that the anchorage of the prostheses was stable and the lumen was uniformly covered by a thin neointimal layer of endothelial like cells. The prostheses were patent with no evidence of thrombosis or inflammation. In view of the problem of recurrent stenosis occurring during the healing period after balloon angioplasty (PTA or PTCA), this approach may lead to a new means of clinical intervention in atherosclerosis.

Alloys↗
PubMed1984

Dietary protein supplementation from vegetable sources in the management of chronic portal systemic encephalopathy.

In a controlled cross-over trial, we have compared a conventional 40-g protein diet (30 g animal and 10 g vegetable, diet A) with an 80-g vegetable-protein-supplemented diet (30 g animal and 50 g vegetable, diet B) in the treatment of six patients with chronic stable portal systemic encephalopathy, requiring dietary and lactulose therapy. Each diet was given, in random order, for 5 days in hospital. EEG, clinical indices of encephalopathy, and the plasma amino acid profile were assessed at the end of each treatment period. The increase in vegetable protein intake was associated with minor improvement in EEG and clinical performance in two patients, and no change in the others. Fasting plasma phenylalanine and tyrosine were higher on diet B [phenylalanine 108.6 +/- 9.3 (SEM) mumol/L versus 99.6 +/- 8.37, p less than 0.05 (paired t test); tyrosine 153 +/- 15.2 mumol/L versus 140 +/- 14, p less than 0.05). The plasma branched-chain amino acid levels did not change, and the branched chain/aromatic amino acid ratio (BCAA/AAA) was lower on diet B (p less than 0.02). Fecal weights were not significantly altered. These results indicate that patients with chronic portal systemic encephalopathy are tolerant of protein supplementation from vegetable sources. A minor improvement in parameters of encephalopathy was seen in some individuals, despite a lowering of BCAA/AAA which some investigators have thought important in the pathogenesis of encephalopathy.

Adult↗