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Biomedical subjects

G Ross

Publications and source records attributed to G Ross.

At least 325 records · Page 18Linked to original sources
PubMedDate not supplied

The greater susceptibility of North Ronaldsay sheep compared with Cambridge sheep to copper-induced oxidative stress, mitochondrial damage and hepatic stellate cell activation.

Sheep of the semi-feral North Ronaldsay (copper-sensitive) and domesticated Cambridge (copper-tolerant) breeds were compared in respect of pathological changes and protein expression in the liver as a result of excessive dietary copper. Acute mitochondrial damage and hepatic stellate cell (HSC) activation with collagen synthesis occurred in response to moderate copper overload in North Ronaldsay but not in Cambridge sheep. Mitochondrial degradative changes occurred either as ballooning degeneration and rupture with subsequent autophagic degradation or as mitochondrial matrical condensation (pyknosis). In North Ronaldsay sheep prolonged exposure to copper produced mitochondrial hyperplasia and hypertrophy, and nuclear damage with necrosis. Cytosolic isocitrate dehydrogenase (IDH), an enzyme responsive to oxidative stress, was induced in the liver of Cambridge sheep receiving a Cu-supplemented diet but was undetectable in the non-supplemented control sheep. Conversely, IDH was detected at similar levels in both control and copper-supplemented North Ronaldsay sheep, indicating a lower threshold response, and an enhanced susceptibility, to oxidative stress. "Upregulation" of mitochondrial thioredoxin-dependent peroxidase reductase (antioxidant protein-1) in the hepatic cytosol of the North Ronaldsay (but not Cambridge) sheep affirmed the increased susceptibility of the mitochondria to Cu-induced oxidative stress in this breed. Likewise the upregulation of cathepsin-D indicated increased lysosomal activity and HSC activation. The findings may be relevant to copper toxicosis in human infants.

Animals↗
PubMedDate not supplied

Afferent nerves are involved in the febrile response to injection of LPS into artificial subcutaneous chambers in guinea pigs.

In guinea pigs, fever was induced by injections of 100 or 10 microgram/kg lipopolysaccharide (LPS) into artificial subcutaneous chambers and analysed under the influence of the local anesthetic, ropivacaine (ROPI), which was administered into the chamber at a dose of 10 mg/kg 30 min prior to LPS. In response to injections of 100 microgram/kg LPS into the subcutaneous chambers, fever was not modified by pretreatment with ROPI. High amounts of bioactive tumor necrosis factor (TNF) alpha and interleukin-6 (IL-6) were measured in the lavage of the chambers after administration of LPS. Comparatively low concentrations of both cytokines (0.5-4% of the concentrations in the lavage fluid) were detected in blood plasma simultaneously. In response to injections of 10 microgram/kg LPS into the subcutaneous chambers, fever was significantly reduced by pretreatment with ROPI to about 60% of the febrile response of control animals. Levels of TNF and IL-6 were lower in response to the reduced dose of LPS. TNF in plasma was even below the limit of detection. The suppression of fever by the local anesthetic was not observed when ROPI was subcutaneously injected into the contralateral site of the chamber position so that a systemic effect of ROPI in the reduction of fever can be excluded. The results indicate a participation of afferent neural signals in the manifestation of fever. This effect becomes obvious only if the dose of the applied inflammatory stimulus (LPS) is not high enough to activate a systemic generalised inflammatory response.

Amides↗
PubMedDate not supplied

Cultivation of an ovine strain of Ehrlichia phagocytophila in tick cell cultures.

Ehrlichia phagocytophila (previously known as Cytoecetes phagocytophila) which causes tick-borne fever (TBF) in sheep and pasture fever in cattle in the UK and mainland Europe is transmitted by the temperate hard tick Ixodes ricinus. The disease in sheep is characterized by fever, leucopenia and immunosuppression. Studies on the pathogenesis and other aspects of the disease have been hampered because the organism has not been cultivated in continuous or primary cell culture systems. This paper describes the first successful cultivation of a European isolate of E. phagocytophila in two continuous cell lines, IDE8 and ISE6, derived from the temperate hard tick Ixodes scapularis. Once adapted to tick cell cultures the organism was serially sub-cultured in new cells by transferring small portions of infected cell suspension every 2 to 3 weeks. The identity of the organism was confirmed by polymerase chain reaction (PCR), with primers specific to the granulocytic ehrlichiae. Sequence analysis of the PCR products amplified from infected tick cells were shown to be identical with those amplified from the blood of sheep infected with the same strain of E. phagocytophila. A susceptible sheep inoculated with a third passage of the tick cell-adapted E. phagocytophila reacted with fever and rickettsiaemia 5 days later, thus satisfying Koch's postulates.

Anaplasma phagocytophilum↗
PubMedDate not supplied

The breast cancer prevention diet by Dr. Bob Arnot: unscientific and deceptive--a disservice to American women.

The following report is a critical review of the recently published book by NBC's chief medical correspondent, Dr. Bob Arnot, entitled, The Breast Cancer Prevention Diet: The Powerful Foods, Supplements, and Drugs That Can Save Your Life. The review represents the official opinion of the American Council on Science and Health (ACSH), a nonprofit public health education and advocacy group supported by a board of over 250 scientific and policy advisors. The scientists at the ACSH express their profound concern about the misleading, unscientific, and speculative advice that Dr. Arnot offers to women who wish to reduce their risk of breast cancer, i.e., to all women. The ACSH believes, first, that in the absence of sound, peer-reviewed evidence supporting such advice, there is harm in recommending lifestyle modifications for the purpose of preventing breast cancer. The ACSH also believes that a physician (and particularly one in a position of public trust, such as a professional media health expert) should refrain from selling advice based on the twin philosophies that "you can't afford to wait" for the evidence, and that "you can only improve your health" with this diet. Indeed, unproven interventions such as those put forth in this book can have negative effects on both physical and psychological health. The ACSH contacted many of the scientists quoted or cited in Dr. Arnot's book. Some expressed concerns regarding the book's message or the misrepresentation of their work or both. Those physicians affiliated with the Memorial-Sloan Kettering Cancer Center (MSKCC) in New York, while expressing their concerns about the claims made in the book, informed the ACSH that they had been "advised" not to comment on The Breast Cancer Prevention Diet. The MSKCC public relations office acknowledged that the center had serious concerns about the Arnot book and that these concerns had been conveyed to the publisher, Little, Brown and Co., and to Dr. Arnot. The MSKCC representative noted that Dr. Arnot had "graciously" agreed to delete all references to MSKCC from future editions.

Breast Neoplasms↗
PubMedDate not supplied

Evaluation of a critical pathway for pneumonia.

Pneumonia is the third most frequent admission diagnosis at Macomb Hospital Center. The average length of stay for this diagnosis (DRGs 89 and 90) was 9.07 days. After the initiation of a critical pathway that begins in the emergency department, the average length of stay decreased to 7.11 days. Quality of care also improved in two areas: the time elapsed before delivery of antibiotics and availability of X-ray reports. This article reviews the implementation and results of the critical pathway for pneumonia.

Critical Pathways↗
PubMedDate not supplied

The relative incidence of anterior cruciate ligament injury in men and women at the United States Naval Academy.

The purpose of this study was to evaluate the relative risk of anterior cruciate ligament injury in female versus male midshipmen at the United States Naval Academy. From 1991 to 1997, we recorded the incidence of anterior cruciate ligament injury during intercollegiate athletics, intramural athletics, and military training. The subjects were male and female varsity athletes, coed intramural athletes, and participants in military training consisting of the obstacle course and instructional wrestling. All patient data were collected at the time of injury. Records filed at the intramural sports office, along with a questionnaire completed by coaches and trainers, were used to estimate midshipmen exposures. Results showed that in intercollegiate soccer, basketball, and rugby, women had a relative injury risk of 3.96 compared with men. In coed soccer, basketball, softball, and volleyball, the women's relative injury risk was 1.40 compared with men. In military training, women had a relative injury risk of 9.74 compared with men. In comparing overall annual anterior cruciate ligament injury rates among midshipmen, we found that women had a relative injury risk of 2.44 compared with men. We concluded that female midshipmen have an increased relative risk of anterior cruciate ligament injury as compared with men in intercollegiate athletics, basic military training, and throughout their service academy career. This increase was not statistically significant at the intramural level of athletics.

Adolescent↗
PubMedDate not supplied

Magnetic resonance imaging for the evaluation of acute posterolateral complex injuries of the knee.

Clinical evaluation of posterolateral complex injuries of the knee can be difficult. To determine if magnetic resonance imaging can assist in decision-making in the treatment of posterolateral complex injuries, six consecutive patients with acute posterolateral knee trauma were imaged preoperatively with standard magnetic resonance imaging sequences. Magnetic resonance imaging findings were then correlated with results of examination under anesthesia or open lateral reconstruction. There were five complete lateral complex injuries (grade III) and one partial tear. Magnetic resonance imaging was able to accurately depict the extent of injury preoperatively in each case. All patients had concomitant anterior cruciate ligament tears. There was one partial posterior cruciate ligament tear. Visualization of the arcuate complex, biceps femoris tendon, lateral capsule, iliotibial band, popliteal tendon, and lateral collateral ligament was possible. A characteristic bone contusion on the anteromedial femoral condyle was present in all patients with complete posterolateral disruptions. Lateral complex injuries of the knee can be very accurately demonstrated on magnetic resonance imaging, and this imaging technique can be used to clarify the exact nature of the injury to allow better surgical planning.

Acute Disease↗
PubMedDate not supplied

Treatment of simple elbow dislocation using an immediate motion protocol.

The results of treatment after closed reduction of elbow dislocation vary. Twenty consecutive patients with closed posterior elbow dislocations were treated prospectively on a rapid motion, nonimmobilized functional regimen. This treatment protocol emphasizes immediate active range of motion under close supervision. No slings or splints were employed. Final range of motion averaged -4 degrees to 139 degrees. All patients attained final extension within 5 degrees of the contralateral side. Each patient achieved his final range of motion within an average of 19 days after reduction of the dislocation. Arm circumference returned to normal at an average of 6.5 days. There was one redislocation. After treatment, all patients met qualification for graduation from the U.S. Naval Academy and were able to pursue unrestricted athletic and career options. Our findings suggest that an aggressive immediate motion rehabilitation allows nearly full final elbow motion and an excellent functional outcome.

Adolescent↗
PubMedDate not supplied

Involvement of male-specific minor histocompatibility antigen H-Y in epidermal equivalent allograft rejection.

This study describes the involvement of male-specific minor histocompatibility antigen H-Y in vitro cultured epidermal equivalent (EE) rejection. Male and female Balb/c or C3H/HeN keratinocytes were isolated and cultured separately. Male EE were grafted onto adult male (isografts) and adult female (H-Y allografts) mice. As controls, Balb/c EE were grafted onto adult C3H/HeN (complete allografts) mice. Fourteen, 21, and 30 days postgrafting, histological studies showed well-organized cutaneous tissues with complete basement membranes (laminin and type IV collagen deposition) in H-Y allografts compared to the isografts. This cutaneous organization was altered 150 days postgrafting, which is a sign of the H-Y EE allograft rejection. Complete allografts were totally rejected 21 days postgrafting. Immunological studies revealed leucocyte infiltration of H-Y allografts. Significant infiltration was detected even 150 days postgrafting. Leucocyte phenotyping revealed the presence of Mac-I+, CD8+ and CD4+ cells in the H-Y allografts. Humoral immune analysis revealed the presence of circulating anti-H-Y allogeneic keratinocyte cytotoxic antibodies in female recipient sera. Our data suggest that male-specific minor histocompatibility antigen H-Y induces cellular and humoral activation of the recipient immune system even after grafting EE free of cutaneous active immune cells such as T lymphocytes and Langerhans cells.

Animals↗