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Biomedical subjects

J Mahoney

Publications and source records attributed to J Mahoney.

At least 55 records · Page 3Linked to original sources
PubMed1989

Non-neurogenic soft tissue tumours of the axilla: prospective review of 16 cases.

Sixteen consecutive patients entered in a prospective study of non-neurogenic soft tissue tumours had lesions in the axilla. Delayed diagnosis and inappropriate biopsy prior to referral to a surgical oncologist were frequent findings. Sarcoma and fibromatosis were diagnosed in 14 cases, and the approaches used for these two diseases were fundamentally different. The functional outcome with limb salvage surgery in these patients is presented.

Adolescent↗
PubMed1989

Salvage of the infected groin vascular graft with muscle flaps.

Debridement and reconstruction of the infected groin wound, including those involving prosthetic graft material, have been performed in eight patients. Healing of the groin wound with functional preservation of the graft has been possible. Our patients have been followed up for at least six months. The procedure described here is a useful addition to the surgical armamentarium for battling this difficult problem.

Aged↗
PubMed1989

Nonoperative management of complications of percutaneous renal nephrostomy.

Between 1984 and 1986 at the Wellesley Hospital in Toronto, 210 percutaneous renal nephrostomies were performed for drainage and 140 were done to provide access for nephrolithotomy. Less than 2% of the patients experienced complications requiring intervention and less than 0.5% required an open surgical approach for the management of procedure-related problems. Complications that were managed conservatively included splenic puncture, false aneurysm, laceration of the renal artery, arteriovenous fistula, hemorrhage requiring transfusion, pneumothorax-empyema, urinoma, septic shock and the hemolysis-hyponatremia-renal shutdown syndrome.

Adult↗
PubMed1989

Effect of capsulectomy on the hemodynamics and viability of random-pattern skin flaps raised on expanded skin in the pig.

Skin flaps constructed on expanded skin usually include the underlying capsular tissue. It has been hypothesized that capsulectomy may jeopardize the viability of the expanded skin flap. The experiments reported herein were designed to test this hypothesis. Specifically, we studied the hemodynamics and viability of random-pattern skin flaps (8 X 20 cm) raised on delayed bipedicle flaps (group A) and on expanded skin pockets with capsulectomy at the time of flap elevation (group B) or with intact underlying capsular tissue (group C). Each group was randomly assigned to each flank in 16 pigs. Skin pockets were expanded by inflation of subcutaneous silicone tissue expanders with sterile saline (299 +/- 7 ml; X +/- SEM) over a period of 3 weeks. At the end of this period, the bipedicle flaps were constructed. Eight days later, random-pattern skin flaps were raised on bipedicle flaps and skin pockets. The length and area of skin flap viability, judged by the fluorescein dye test performed 1 day postoperatively, were not significantly different (p greater than 0.05) among groups A, B, and C (n = 31 to 32). There also were no significant differences (p greater than 0.05) in total skin capillary blood flow measured 1 day postoperatively (A = 2.6 +/- 0.4, B = 2.4 +/- 0.4, and C = 2.7 +/- 0.6 ml/min per flap; n = 15 to 16) and in skin viability assessed 7 days postoperatively (A = 74 +/- 2, B = 75 +/- 2, and C = 76 +/- 2 percent; n = 16) among delayed skin flaps and skin flaps raised on expanded skin pockets with or without capsulectomy. The results of this flap viability study were confirmed in 5 minipigs in a separate experiment. We conclude that capsulectomy did not have a detrimental effect on the hemodynamics and viability of random-pattern skin flaps raised on expanded skin. Furthermore, we hypothesize that skin flaps raised on expanded skin are similar to delayed skin flaps in that the skin blood flow is optimally augmented; therefore, the capsular tissue does not add significant blood supply to the overlying skin.

Animals↗
PubMed1988

Altered hepatic calcium homeostasis in guinea pigs with halothane-induced hepatotoxicity.

Exposure of guinea pigs to 1% halothane in air for 4 hr resulted in extensive centrizonal hepatic necrosis in 70% of animals examined 2 to 3 days later. In contrast, confluent hepatic necrotic lesions were not present in animals studied 24 hr after halothane exposure; only microvascular fatty change of hepatocytes with occasional necrotic cells was observed at that time (in 84% of animals). This delayed onset of lesion development afforded the opportunity to study microsomal membrane composition and indices of Ca++ homeostasis before and after the onset of halothane-induced hepatic necrosis. Hepatic microsomal cytochrome P-450 levels were unaltered 24 hr after halothane exposure, but fell to approximately 50% of control values at 72 hr. This indicates that such changes were most likely the result of hepatocellular necrosis. Microsomal lipid composition, including the relative proportions of individual phospholipids, was unaltered during halothane-induced hepatotoxicity. In contrast, microsomal Ca++ sequestration, as assessed by 45Ca uptake, was reduced 24 hr after halothane exposure compared with controls (2.76 +/- 1.32 nmol/mg of protein per min, vs. 6.63 +/- 2.88 nmol/mg of protein per min, P less than .001). This early change in microsomal Ca++ uptake was associated with a 10-fold increase in total hepatic Ca++ content at 24 hr. Subsequent changes in hepatic Ca++ content were proportionate to the severity of liver necrosis. The observation that abnormalities of hepatic Ca++ homeostasis antedate the presence of liver cell necrosis is consistent with a role for altered Ca++ fluxes in the mechanism of halothane-induced liver injury.

Alanine Transaminase↗
PubMed1987

Toe transfer to the vessels of the reversed forearm flap.

A 23-year-old man had a severe degloving injury of his hand, amputation of multiple fingers, and devascularization of the thumb. Primary care consisted of successful revascularization of the thumb and skin grafting of the hand. Secondary soft tissue reconstruction of the hand was done with a reverse forearm flap. This was followed by second-toe transfer to the hand, with the recipient vessels, the radial artery, and the venae comitantes of the reverse forearm flap.

Adult↗
PubMed1987

Posterior wall disruption of the left ventricle after mitral valve replacement: management of bleeding and cardiac enlargement.

Two patients who underwent mitral valve replacement sustained posterior left ventricular disruption postoperatively and survived. Management consisted of repair from outside the heart without removal of the mitral prosthesis. This was achieved with a running Prolene suture in the atrioventricular junction in one patient and pledgeted sutures in the other who had transverse midventricular disruption. Biologic glue was crucial in controlling hemorrhage after the repair in both cases. The patient with transverse midventricular disruption required placement bilaterally of pectoralis muscle flaps to close the sternal wound because of swelling and dilatation of the heart.

Aged↗
PubMed1985

Purification of cachectin, a lipoprotein lipase-suppressing hormone secreted by endotoxin-induced RAW 264.7 cells.

Previous studies have indicated that endotoxin and other bacterial and protozoal products can stimulate macrophages to produce a factor that can suppress the activity of the enzyme lipoprotein lipase (LPL), in vivo and in vitro. In the present report we describe the purification of this factor, cachectin, to apparent homogeneity from the conditioned medium of endotoxin-stimulated RAW 264.7 cells. The isolated protein has an isoelectric point of 4.7 and a subunit molecular weight of 17,000. Although cachectin's isoelectric point and molecular weight are similar to those described for interleukin 1, pure cachectin has no leukocyte-activating factor (LAF) activity. Cachectin at a concentration of 10(-11) M has the ability to suppress the LPL activity of the 3T3-L1 adipocyte cell line by 80%. Binding studies using radio-labeled cachectin and 3T3-L1 adipocytes and C2 myotubules revealed approximately 10(4) high-affinity receptors per cell on both cell types (Ka, 3 X 10(9]. Cachectin receptors were also present on liver membranes but were absent on erythrocytes and lymphocytes. The isolation of cachectin and characterization of its receptor should facilitate further investigations into the role of cachectin and other macrophage mediators in the metabolic derangements that occur during infection and cachexia.

Adipose Tissue↗
PubMed1985

Use of influenza A virus vaccines in seronegative children: live cold-adapted versus inactivated whole virus.

We report the safety and antigenicity of influenza A vaccines in seronegative children one to seven years of age. A natural H1N1 challenge that occurred shortly after completion of the vaccination program permitted an evaluation of efficacy. Twenty-eight subjects were inoculated with live cold-adapted (ca) influenza A/Washington/897/80 (H3N2), 29 with ca influenza A/California/10/78 (H1N1), 24 with inactivated whole-virus influenza A/Bangkok/79 (H3N2), and 30 with a placebo. The ca vaccines were well tolerated, whereas the inactivated vaccine caused adverse reactions in about one-third of the children. Fifty-seven percent of the ca H1N1 recipients showed serological responses, contrasted with 84% and 100% of subjects receiving the ca or inactivated H3N2 vaccines, respectively. None of the 16 children with induced H1N1 antibody developed clinically apparent influenza-like illness, compared with eleven of the 51 initially seronegative children who did not receive the ca H1N1 vaccine and with four of the 12 who failed to respond. Results of the efficacy field trial suggest protection against infection and symptomatic illness in children inoculated with ca H1N1, despite its failure to stimulate high levels of hemagglutinin-inhibiting antibody.

Antibodies, Viral↗
PubMed1985

On the immunogenicity of the beta subunit of ovine luteinizing hormone (oLH beta) and equine chorionic gonadotropin (eCG) in the chimpanzee (Pan troglodytes): effect of antiserum on monkey cycle and early pregnancy.

Antibody to ovine LH beta (oLH beta) subunit and equine chorionic gonadotropin (eCG) were produced in adult male chimpanzees and evaluated for cross reactivity with oLH, human chorionic gonadotropin (hCG) and eCG by in vitro and in vivo methods. Chimpanzee antiserum to eCG failed to cross-react with hCG, but antibody raised against oLH beta subunit effectively neutralized not only exogenously administered hCG but also endogenous pituitary LH and monkey (Macaca radiata) chorionic gonadotropin. Chimpanzee antiserum to oLH beta when administered early in pregnancy reduced progesterone levels and terminated gestation in bonnet monkeys. Our data suggest that active immunization of chimpanzee, an ape that is very close to human, with oLH beta subunit leads to production of antibodies that are likely to affect both normal cycle as well as pregnancy.

Animals↗
PubMed1985

Hospice.

Explore the source record for details and available documents.

Aged↗
PubMed1985

Treatment of the chronically infected median sternotomy wound with muscle flaps.

While infection and dehiscence of the median sternotomy wound is a serious complication, débridement, sternal rewiring and wound irrigation will often result in wound healing. However, if these measures fail, radical débridement of all infected tissue and immediate reconstruction with muscle flaps is required and will give excellent results. The pectoralis major muscle based on the thoracoacromial artery is most satisfactory for this reconstruction. The rectus abdominis muscle, while also used, is not as effective because of variations in its proximal blood supply. The author describes 10 patients with chronically infected median sternotomy wounds, seen at St. Michael's Hospital in Toronto, in whom use of these techniques led to a rapid recovery with few complications.

Aged↗
PubMed1982

16 PF correlates of perceptual reactance.

College students (n = 24 males, 36 females) volunteered to take the kinesthetic figural aftereffect task and the 16 PF in a survey of state versus trait personality correlates of perceptual reactance. A reliable emergence of the trait component of perceptual reactance over trials was noted. Perceptual reducers were outgoing, affected by feelings, happy-go-lucky, practical, and undisciplined, while augmenters were reserved, stable, sober, imaginative, and controlled. Findings tend to support the trait model of perceptual reactance, with interference from a state component.

Female↗