Biomedical subjects

Roger W Soames

Publications and source records attributed to Roger W Soames.

9 recordsLinked to original sources

PubMed2006

The posterior longitudinal ligament and peridural (epidural) membrane.

The posterior longitudinal ligament (PLL) is described as having deep and superficial layers, though recent studies have suggested that there may be three layers. Additional membranous structures have been reported, although there is no consensus as to their presence or morphology. The vertebral canal and dural sac were opened and the spinal nerve roots and spinal cord removed. The anterior dural ligaments were sectioned at their attachment to the PLL and the dura mater freed from the posterior surface of the vertebral bodies. The borders of the PLL were identified and the superficial and deep layers separated. The PLL is a wide band in the cervical region becoming more denticulate inferiorly, the widest parts being attached to the intervertebral discs (IVD) and adjacent vertebral body where the superficial and deep layers could not be separated. A continuous well developed peridural membrane attaching to the pedicles was present anterior to the deep PLL as well as a separate, thin, incomplete layer in 6 of 18 cadavers, covering the posterior surface of the superficial PLL.

Aged↗

PubMed2005

The anterior visceral branches of the abdominal aorta and their relationship to the renal arteries.

Variations in the anatomy of the abdominal aorta and its branches are of interest as vessel geometry not only determines flow dynamics, but is also crucial in the pathogenesis of vascular disease. The relationship between the anterior visceral and renal arteries is important when undertaking diagnostic arteriography and endovascular interventions. To examine these relationships, the length of the abdominal aorta was determined and measurements taken of the position of origin of the celiac artery, superior mesenteric artery (SMA), inferior mesenteric artery (IMA) and renal arteries, as well as the three-dimensional projection of each vessel from the aorta. The mean level of bifurcation of the aorta was at the lower third of the body of L4, with the celiac artery, SMA, renal arteries and IMA arising at the level of the T12/L1 intervertebral disc, upper third of the body of L1, lower third of the body of L1 and lower third of the body of L3, respectively. The horizontal projection of the celiac artery, SMA and IMA was to the left of the midline; in the sagittal plane, the celiac artery and SMA projected anteriorly and the IMA posteriorly; in the coronal plane all vessels projected inferiorly, with the SMA to the right and the IMA to the left. The celiac artery, SMA and both renal arteries all arise from the proximal half of the abdominal aorta within 45 mm of each other, with the origins of the renal arteries being remarkably consistent. It is concluded that the celiac artery and SMA are both useful landmarks for determining the position of the renal arteries.

Abdomen↗

PubMed2005

Effect of patellar tendon shortening on tracking of the patella.

BACKGROUND: Although 10% postoperative patellar tendon shortening after bone-patellar tendon-bone autograft reconstruction of the anterior cruciate ligament has been reported, there are no published studies assessing the effect of shortening on patellofemoral joint biomechanics under physiological loading conditions. PURPOSE: To investigate the influence of patellar tendon shortening on patellofemoral joint biomechanics. STUDY DESIGN: Controlled laboratory study. METHODS: The authors evaluated the patellofemoral contact area, the location of contact, and the patellofemoral joint reaction force and contact stresses in 7 cadaveric knees before and after 10% patellar tendon shortening. Shortening was achieved using a specially designed device. Experimental conditions simulating those occurring during level walking were employed: physiological quadriceps loads and corresponding angles of tibial rotation were applied at 15 degrees , 30 degrees , and 60 degrees flexion of the knee. Patellofemoral joint contact areas were measured before and after shortening using the silicone oil-carbon black powder suspension squeeze technique. RESULTS: After patellar tendon shortening, patellofemoral joint contact areas were displaced proximally on the patellar surface and distally on the femoral surface. Although the contact area increased by 18% at 15 degrees of knee flexion (P = .04), no significant change occurred at 30 degrees or 60 degrees of knee flexion (P > .05). Patellofemoral contact stress remained unchanged after patellar tendon shortening (P > .05) at each flexion angle. CONCLUSION: Our results suggest that a 10% shortening of the patellar tendon does not alter patellar contact stresses during locomotion. It is not clear whether apparent changes in contact location in all positions and contact area at 15 degrees would have clinical consequences.

Aged, 80 and over↗

PubMed2005

Effects of cagA+ and cagA- strains of Helicobacter pylori on the human gastric mucus layer thickness.

BACKGROUND: Infection with cytotoxin-associated gene A (cagA) Helicobacter pylori is associated with severe gastric diseases, with contradictory views being expressed concerning the effect of H. pylori on the gastric mucus thickness. The aim of the present study was to differentiate between the effect of cagA+ and cagA- strains on gastric mucus thickness. METHODS: Ninety-nine patients without peptic ulcers who were not on medication were randomly recruited from consecutive endoscopy clinics: six biopsies (five antral, one body) were obtained from each patient. Cryostat sections (18 microm) were cut and stained using the modified periodic acid-Schiff/Alcian blue technique. Mucus thickness was measured using computer-assisted light microscopy. The H. pylori status was assessed by histology, Campylobacter-like organism (CLO)test and culture, and cagA+ status determined by polymerase chain reaction (PCR). RESULTS: There was no significant difference (P = 0.784) in mean mucus thickness between cagA+ (52.7 +/- 1.2 microm, n = 10), cagA- (46.6 +/- 1.1 microm, n = 18) or H. pylori-negative patients (51.3 +/- 1.1 microm, n = 30). In cagA- patients, mucus thickness was significantly reduced with increased H. pylori colonization density, Spearman (r(s)) = -0.805, P < 0.0001. In contrast, in cagA+ patients there was a weak positive, but not significant, association between mucus thickness and H. pylori colonization density, r(s) = 0.333, P = 0.381. CONCLUSIONS: The human gastric mucus thickness is not affected by infection with cagA+ or cagA- strains of H. pylori compared with uninfected. Although a trend of increased mucus thickness with cagA+ infection was observed.

Adolescent↗

PubMed2005

Human gastric mucosal hydrophobicity does not decrease with Helicobacter pylori infection or chronological age.

BACKGROUND AND AIMS: Infection with cytotoxin-associated gene A (cagA) Helicobacter pylori is associated with severe gastric diseases. Previous studies in humans have reported a decreased gastric hydrophobicity with H pylori infection. The aim of the present study was to differentiate between the effect of cagA+ and cagA- strains on gastric mucus hydrophobicity. METHODS: One hundred patients without peptic ulcers and not on medication were randomly recruited from endoscopy clinics; each patient had six biopsies. Contact angle measurements were performed using a goniometer assisted by computer software. H pylori status was assessed by histology, Campylobacter-like organism test and culture, and cagA+ status was determined by polymerase chain reaction. RESULTS: In age- and sex-matched patients, there was no significant difference (P=0.27) in contact angle between H pylori-positive (61+/-2.8 degrees ) and H pylori-negative patients (65.5+/-3.0 degrees ). There was also no significant difference (P=0.36) in contact angle among H pylori-negative, cagA- and cagA+ patients (65.5+/-3.0 degrees , 58.6+/-3.6 degrees and 63.4+/-4.9 degrees , respectively). However, a trend of increased mean contact angles in cagA+ compared with cagA- and H pylori-negative patients was observed in patients 50 years and younger (68.3+/-8.3 degrees , 61.1+/-6.1 degrees and 63.6+/-2.2 degrees , respectively; P=0.70) and in patients without atrophy (71.1+/-8 degrees , 59.6+/-4 degrees and 66+/-2 degrees , respectively; P=0.30). In addition, there was no significant correlation between contact angles and patient age (r=0.104, P=0.306). CONCLUSIONS: The present study shows that H pylori infection and the chronological age have no effect on the gastric mucus hydrophobicity, but it highlights a trend of increased mucus hydrophobicity with cagA+ infection that needs to be supported by future studies.

Adult↗

PubMed2005

Selectively attenuating soft tissues close to sites of inflammation in the peritalar region of patients with rheumatoid arthritis leads to development of pes planovalgus.

OBJECTIVE: To compare the 3-dimensional (3D) orientation of the tibiotalar, tibiocalcaneal, and intertarsal joints in cadaveric specimens following structural weakening to predetermined ligaments in the peritalar region and medial ankle tendons under axial loads and simulated calcaneal valgus deformity. METHODS: Eight fresh-frozen, unembalmed human lower leg and foot specimens were placed in a materials testing machine. The mid-stance period of gait was simulated and the 3D orientation of the tibiotalar, tibiocalcaneal, and intertarsal joints was measured using an electromagnetic motion analysis system. Specimens were then axially loaded at 840 N for 5400 cycles with the calcaneus in its initial orientation and under simulated valgus conditions using a heel wedge following attenuation (multiple stab incisions) of selected ligaments (tibionavicular, anterior tibiotalar and tibiocalcaneal portions of the medial deltoid ligament, the inferior calcaneonavicular ligament, and the superomedial calcaneonavicular ligament) or tendons (tibialis posterior, flexor digitorum longus, and flexor hallucis longus). The joint orientation measurements were then repeated and compared with baseline intact measurements. RESULTS: Pes planovalgus was observed in 6/8 specimens following testing. The tibiotalar, tibiocalcaneal, talonavicular, and calcaneocuboid joints were more dorsiflexed, everted, and externally rotated following either ligament or tendon compromise. The changes in orientation were small but showed consistent patterns with the smallest changes (typically < 1 degrees ) for the transverse plane and largest (up to 3.5 degrees ) for the frontal plane. The magnitude of change was similar for the tibiotalar and tibiocalcaneal joints, largest for the talonavicular joint, and smallest for the calcaneocuboid joint for both ligament and tendon compromise. The orientation of the talocalcaneal joint was more plantarflexed and everted relative to baseline, for both the ligament and tendon compromise with < 1 degrees of change in orientation about the transverse plane. Under simulated valgus heel conditions, joint orientation was further increased especially about the frontal plane in the direction of eversion. The smallest changes were noted for the calcaneocuboid joint (approximately 1 degrees ), similar change (approximately 2-3 degrees ) for the tibiotalar, tibiocalcaneal and talocalcaneal joints, and the largest changes (> 3 degrees ) for the talonavicular joint. There were no observed differences in the magnitude of change between ligament or tendon condition. CONCLUSION: Selective attenuation to either the ligaments supporting the tibiotalar, talocalcaneal, and talonavicular joints or the medial ankle tendons followed by cyclic loading results in small but important changes in the orientation of the tarsal bones consistent with the development of pes planovalgus.

Ankle Joint↗

PubMed2005

Helicobacter pylori. Basics and clinical overview.

The discovery of Helicobacter pylori (H. pylori) has greatly changed the approach to the management of peptic ulcer disease and gastric cancer. A sound knowledge of the basics of H. pylori is an important aid in the diagnosis and treatment of clinical conditions associated with this infection. Gastric carcinoma is estimated to be the world's second most common cancer as a cause of death. It is hoped that gastric cancer can be prevented by H. pylori eradication; however, this issue is still under investigation. Active research is ongoing to highlight the mechanisms by which H. pylori leads to severe gastric diseases as well as finding associations with extra-gastric diseases.

Helicobacter Infections↗

PubMed2004

cagA+ Helicobacter pylori induces greater levels of prostaglandin E2 than cagA- strains.

cagA+ Helicobacter pylori (HP) infection is associated with an increased risk of distal gastric cancer. Previous studies investigating the effect of HP infection on prostaglandin E2 (PGE2) levels have not differentiated between cagA+ and cagA- strains and consequently have produced contradictory results. The aim was to investigate the effect of cagA+ strains on PGE2 and enhance the understanding of the mechanisms leading to gastric diseases. Hundred patients without peptic ulcers and not on medication were recruited (one later excluded) from endoscopy clinics: six biopsies were obtained from each patient. PGE2, colonization density and histology were determined. In addition, HP status was assessed by histology, CLOtest and culture with cagA+ being determined by PCR. Sixty-nine patients were HP- and 30 HP+ (10 cagA+, 18 cagA-, 2 undetermined). In age and sex-matched patients, PGE2 was significantly greater (P = 0.04) in HP+ (37.2 +/- 1.2 pg/mg per 20 min) than in HP- (22.6 +/- 1.2). In patients without atrophy, those infected with cagA+ had significantly higher (P = 0.03) PGE2 levels (53 +/- 1.1) than HP- patients (22.6 +/- 1.1) and greater levels (P = 0.29) than cagA- patients (35 +/- 1.3). In conclusion, the increased levels of PGE2 in the presence of cagA+ infection could be an important factor by which cagA+ strains enhance the gastric mucus layer protective functions leading to established colonization, gastritis and increased risk of gastric cancer. However, further evaluation with a large-scale multi-centre study is required to substantiate this hypothesis.

Aged↗

PubMed2004

The association between cagA+ H. pylori infection and distal gastric cancer: a proposed model.

Cytotoxin-associated gene A (cagA)+ infection is associated with an increased risk of distal gastric cancer. The aim was to determine the effect of Helicobacter pylori (HP) on gastric mucus thickness, hydrophobicity, and PGE2 and their relation to colonization density. Ninety-nine patients were recruited (69 HP- and 30 HP+: 10 cagA+, 18 cagA-, 2 undetermined) and six biopsies were obtained from each patient. Mucus thickness, hydrophobicity, PGE2, and colonization density were determined. HP status was assessed by histology and culture; cagA+ was determined by PCR. In age- and sex-matched patients, PGE2 was greater in PH+ than HP- (P = 0.04), with cagA+ having higher PGE2 than HP- patients (P = 0.031). No differences were observed in mucus thickness (P = 0.717) or hydrophobicity (P = 0.27) between HP+ and HP- patients. However, cagA+ showed a nonsignificant trend of increase in mucus thickness (P = 0.784) and hydrophobicity (P = 0.30) compared to cagA- and HP- patients. cagA+ colonization density was weakly correlated with increased thickness (r = 0.333, P = 0.381), whereas cagA- density was inversely correlated with thickness (r = -0.805, P = 0.0001). A model suggesting the possible changes induced by cagA+ infection is proposed which explains the high association of cagA+ with distal gastric cancer. If supported by large multicenter studies, this could form the basis for the development of new therapies directed at the mucous layer to eradicate HP and thus reduce the risk of gastric cancer.

Antigens, Bacterial↗