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Biomedical subjects

C J Cahill

Publications and source records attributed to C J Cahill.

At least 19 recordsLinked to original sources
PubMed2000

Immunoelectron microscopic detection of tissue ganglioside antigens.

Glycolipid antigens are emerging as important markers of differentiated cells in vitro and in vivo. The study of the expression of these antigens in whole tissues by immunoelectron microscopy, using standard techniques, does not give acceptable results. We have established conditions for the specific demonstration of antibody binding to tissue glycolipid antigens by immunoelectron microscopy. Dehydration of tissues with alcohol is to be avoided as it extracts the glycolipid antigen out of the tissue. Dehydration in acetone provides good results. Embedding of the tissue in Araldite 512 results in high non-specific binding of the primary antibody and a decreased effective titre of the primary antibody. Embedding of tissues in Lowicryl HM20 resin resulted in low non-specific binding. We also describe a method of curing the Lowicryl resin that does not require a purpose built curing chamber. Quantitative analysis of immunogold binding reveals that acetone dehydration of tissues and embedding in Lowicryl gives greatly superior results in comparison with dehydration in alcohol and embedding in Araldite.

Animals↗
PubMed2000

Successful defibrillation in profound hypothermia (core body temperature 25.6 degrees C).

We report a case of successful defibrillation in a severely hypothermic patient with a core body temperature of 25.6 degrees C as measured oesophageally. Ventricular fibrillation is a recognised life threatening arrhythmia in severely hypothermic patients. The traditional wisdom is that this arrhythmia is refractory to defibrillation at temperatures below 28 degrees C.

Acute Disease↗
PubMed1997

Apoptosis participates in the remodeling of the endocrine pancreas in the neonatal rat.

In rodents, shortly after birth a lack of increase in pancreatic weight and in islet mass have been reported during a time of overall body weight increase. To understand this regulation of the neonatal growth of the beta cell mass, we studied Sprague Dawley rats at 2, 9, 13, 17, 20, 24, and 31 days of age for beta cell replication, beta cell mass, and cell size and for the presence of cell apoptosis. beta cell mass was stable from 2-20 days (range: 0.91 +/- 0.2 to 1.33 +/- 0.23 mg) and increased thereafter. beta cell replication progressively decreased. Condensed apoptotic nuclei were identified and counted on paraffin sections using the fluorescent dye propidium iodide. Apoptotic beta cell nuclei were found at a basal rate (1.54 +/- 0.22%) at 2, 9, and again after 20 days of age. However, at 13 and 17 days, the incidence of apoptosis was significantly increased (3.64 +/- 0.45%). The decreased replication and the increased incidence of apoptosis in the beta cells strongly suggest a wave of neogenesis of beta cells to maintain the constant beta cell mass. These data show that the endocrine pancreas undergoes significant modification during neonatal life and that apoptosis is an important mechanism in this remodeling of the beta cell mass. Whether a selective deletion of some population of beta cells occurs is unclear, but a dysregulation of this remodeling process could have important effects on the pancreatic beta cell mass.

Animals↗
PubMed1996

Suspension culture of differentiated rat heart myocytes on non-adhesive surfaces.

Cardiac myocytes isolated from adult rat ventricles have been maintained in a stable, differentiated state for prolonged periods by the use of suspension culture on hydrophobic tissue culture inserts or agarose-coated plates. The success of this procedure depends on the use of low-serum media to prevent myocyte-myocyte interaction and proliferation of any residual endothelial cells. Myocytes cultured in this manner retain many of their structural characteristics, suggesting that maintenance of their elongated irregular shape is not dependent on interaction with extracellular matrix. They also exclude trypan blue, can be vitally stained by the uptake and reduction of the tetrazolium dye MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide], synthesize myosin and when returned to adhesive surfaces are capable of attachment and attendant dedifferentiation. Stability of the myocytes in suspension permits their use in co-culture experiments; specifically, myocytes separated from endothelial cells by the hydrophobic membrane of the tissue culture insert stimulated proliferation of the latter cells, suggesting this to be a useful system for studying myocyte-endothelial cell interaction.

Animals↗
PubMed1996

Comparison of diclofenac sodium and morphine sulphate for postoperative analgesia after day case inguinal hernia surgery.

Postoperative pain may be a significant reason for delayed discharge from hospital, increased morbidity and reduced patient satisfaction with ambulatory hernia surgery. This study compared two postoperative oral analgesic protocols after day case inguinal hernia repair; 30 mg morphine sulphate (MST) and 10 mg metoclopramide every 8 h for 48 h or 75 mg diclofenac twice daily for 48 h. The pain reported in the MST group was significantly greater on both the day of operation and the first postoperative day (P < 0.05, Mann-Whitney U test). A significantly higher proportion of patients taking MST complained of nausea on the day of operation and on the 1st postoperative day (P < 0.05, chi 2). The time taken to walk, dress and leave home alone were achieved in a significantly shorter duration in patients taking diclofenac. We conclude that diclofenac provides effective analgesia, has a more acceptable side-effect profile than morphine sulphate and is the treatment of choice after ambulatory hernia surgery.

Activities of Daily Living↗
PubMed1995

An evaluation of hand immersion for rewarming individuals cooled by immersion in cold water.

The hypothesis that hypothermic individuals can be actively rewarmed in the field by immersion of the extremities in hot water was investigated. Three techniques for rewarming subjects with lowered deep body temperatures were compared: a) whole body immersion to the neck in water at 40 degrees C; b) immersion of two hands plus forearms only in water at 42 degrees C; and c) passive rewarming. The suggestion that the fall in deep body temperature resulting from immersion to the neck in water at 15 degrees C could be arrested by immersing both arms in water at 42 degrees C was also investigated. Results indicated that immersion to the neck in hot water was clearly the most effective rewarming technique. No significant difference (p > 0.05) was observed in the deep body temperature response during passive rewarming or during immersion of both hands and forearms in water at 42 degrees C. In the later condition some increase in peripheral blood flow to the hands may have occurred and resulted in a heat input of approximately 12 W, but any benefit from this was negated by an associated significant decrease (p > 0.05) in intrinsic heat production. Immersing the arms in hot water during immersion to the neck in cold water appeared to accelerate rather than decelerate the rate of fall of deep body temperature. We concluded that hand rewarming, although theoretically attractive, is ineffective in practice and could be detrimental in some circumstances, by suppressing intrinsic heat production or precipitating rewarming collapse.

Adult↗
PubMed1992

Expression of a monoclonal antibody (3G5) defined ganglioside antigen in the renal cortex.

The monoclonal antibody (mAb) 3G5 was found, by indirect immunofluorescence, to bind to renal cortical structures in frozen sections of human, rat and calf kidneys. Double indirect immunofluorescence studies on frozen sections of rat kidneys showed that 3G5 stained only the glomerulus and the distribution of the 3G5 antigen on the glomerulus was more extensive than the staining observed with antibodies to Factor VIII antigen. 3G5 stained the proximal convoluted tubules and collecting tubules in bovine renal sections but glomeruli did not stain with 3G5. The 3G5 mAb did not stain tissue cultured bovine glomerular endothelial cells or mesangial cells, but did stain bovine glomerular epithelial cell cultures. 3G5 did not stain MDCK cell cultures. The binding of mAb 3G5 to glomeruli was investigated by immunoelectron microscopy of rat renal tissue. In contrast to the podocyte specificity on bovine glomerular cells in vitro, it was found that the specificity of 3G5 expression on rat glomerular cells in vivo was broader. No binding of mAb 3G5 was found outside the glomerulus in the rat renal cortex. Podocytes, endothelial cells and capsular epithelial cells expressed the 3G5 antigen most strongly. A lesser amount of binding was found in the glomerular basement membrane. The mesangium showed a little binding of mAb 3G5 and no binding at all was found to other cortical structures. The 3G5 antigen in rat renal tissue was found to be a glycolipid that migrated between the ganglioside markers GM2 and GM1 by immunostaining of thin layer chromatograms.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Prevention of postoperative renal dysfunction in patients with obstructive jaundice: a multicentre study of bile salts and lactulose.

The role of preoperative lactulose and bile salts in the prevention of postoperative renal failure in patients with obstructive jaundice has been evaluated in a prospective randomized trial. One hundred and two patients undergoing surgery for obstructive jaundice (bilirubin greater than 100 mumols/l) were randomized into three groups: those receiving preoperative oral lactulose (n = 35), those receiving oral sodium deoxycholate (n = 32) and a control group of patients receiving no specific treatment (n = 35). All patients received intravenous fluids commencing the night before surgery. One patient in the control group and none in the treatment groups developed postoperative renal failure. Postoperative deterioration of renal function in patients with normal preoperative function was significantly more common in the control group than in the treatment groups (chi 2 = 8.1, d.f. = 2, P less than 0.02). The incidence of renal failure and impairment was lower in this control group than that reported in previous studies. This may be due to the introduction of adequate preoperative hydration. Additional protection occurs by the preoperative administration of either lactulose or sodium deoxycholate.

Acute Kidney Injury↗
PubMed1991

Prospective, randomized trial of the biofragmentable anastomosis ring. The BAR Investigational Group.

A randomized trial was undertaken to compare the biofragmental anastomotic ring (BAR) with conventional intraperitoneal colorectal anastomotic techniques. Patients were randomized into one of two schemes: BAR versus sutured or BAR versus stapled anastomosis. There were 782 patients entered into the study and 283 patients (36%) had a sutured anastomosis, 104 patients (13%) had a stapled anastomosis, and 395 (51%) had the BAR. Comparison of the BAR with combined suture and stapled controls revealed no significant differences in wound complication, abscess rate, bleeding, anastomotic leaks, ileus, obstruction, or deaths. There were no differences in return of bowel function, return to normal diet, or hospital stay. Intraoperative difficulties occurred in 46 BAR patients (17%), and this was significantly higher (p less than 0.001) than for sutured (3%) but not for stapled anastomoses (11%). The occurrence of these problems did not adversely effect the outcome. The data suggest that the BAR is a safe, satisfactory alternative to sutured or stapled colorectal anastomoses.

Adolescent↗
PubMed1991

The revascularization of healing flexor tendons in the digital sheath. A vascular injection study in dogs.

The role of revascularization in the nutritional support of repair of the flexor tendons is not completely understood. To explore the extent to which intrasynovial flexor tendons revascularize after transection and suture, a vascular injection study was carried out in a canine model. The tendons to the second and fifth digits of the forepaw in twelve adult mongrel dogs were transected and repaired. There were twenty-four experimental tendons and twenty-four normal tendons. The limb was placed in a polyurethane shoulder-spica cast, and the paw was treated with immediate protected passive mobilization. At three, seven, ten, seventeen, and twenty-eight days, the animals were killed and the major arteries supplying both the paw that had been operated on (left) and the contralateral normal paw (right) were injected with 200 milliliters of India ink. Segments of repaired and normal tendons were then clarified by a modified Spalteholz technique. The normal tendons demonstrated a well developed mesotenon that provided vascularization of the proximal portion of the flexor digitorum profundus tendon. A consistent three-cubic-millimeter avascular intrasynovial portion of tendon was noted. Distally, vessels arose from the vinculum breve, supplying the terminal twenty millimeters of tendon substance. In the experimental tendons, longitudinal and transverse clarified sections showed consistent revascularization of the site of repair by proximal vessels in the absence of ingrowth of peripheral adhesions. Vessels in the epitenon progressively extended for a distance of ten millimeters, through normally avascular regions, to reach the site of repair by the seventeenth postoperative day. Intratendinous vessels about the site of repair consistently originated from surface vessels, rather than from extensions of pre-existing intratendinous vessels. New vessels penetrated all areas, including the normally avascular volar segments of tendon, irrespective of previous topical zones of avascularity. Proximal vascular plexi were characterized by large tortuous vessels with frequent circuitous branches. More distal vessels had a longitudinally oriented, feathery appearance.

Animals↗
PubMed1990

Management of cyclical mastalgia.

In order to establish the current treatment of cyclical mastalgia, a postal questionnaire was sent to 276 consultant general surgeons (over 25% of the UK total), randomly selected from the 12 UK regional health authorities. Surgeons were questioned about their choices of treatment for cyclical mastalgia, after initial resassurance, and for persistent pain. Two hundred and forty-five (89%) responded, out of whom 219 saw patients with breast disease. Twenty-three (11%) of these surgeons were identified as having a major interest in breast disease. Danazol, used by 75% of surgeons, was the drug most commonly prescribed. Initial treatments by non-specialist surgeons included danazol (31%), analgesia (19%) and diuretics (17%), and by breast surgeons evening primrose oil (30%), tamoxifen (13%) and vitamin B6 (13%). For persistent pain 46% of non-specialist surgeons prescribed danazol and 18% surgery, whereas 65% of breast surgeons prescribed danazol and 30% bromocriptine. A wide variety of therapies are used, but danazol is the most common. For persistent unresponsive pain, local excision biopsy surgery is frequently considered by non-specialist surgeons. Breast specialist tend initially to use other methods that are associated with fewer side-effects and reserve other treatments such as danazol and bromocriptine for persistent cases.

Breast↗
PubMed1989

Sutureless large bowel anastomosis: European experience with the biofragmentable anastomosis ring.

Sutureless colonic anastomosis using a biofragmentable anastomosis ring (BAR) has been evaluated in a prospective randomized comparison with sutures and staples for elective colorectal surgery. One hundred and one patients underwent BAR anastomosis, 85 a sutured anastomosis, and 16 a stapled anastomosis. There were two anastomotic leaks in the patients undergoing BAR anastomosis, seven in patients having a sutured anastomosis, and one in a patient who had a stapled anastomosis. Wound infection occurred in ten BAR patients, ten sutured patients and no stapled patient. There was no statistically significant difference in these or in other postoperative complications between the groups. The BAR was easy to use and is a safe alternative to sutures and staples for large bowel anastomosis.

Adolescent↗
PubMed1988

Current practice in biliary surgery.

A questionnaire enquiring about current practices in biliary surgery was sent to over 25 per cent of consultant general surgeons in the UK; 90 per cent replied. Only 56 per cent use antibiotic prophylaxis for elective cholecystectomy, and 84 per cent for emergency cholecystectomy. Duration of use, choice of agent and absence of prophylaxis for high-risk cases were inappropriate in up to 20 per cent of cases. Of the respondents 84 per cent routinely perform operative cholangiography and use T tubes, and 75 per cent routinely place a peritoneal drain after cholecystectomy. Despite controversies in the literature, most UK surgeons still follow traditional practices in biliary surgery.

Anti-Bacterial Agents↗