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Biomedical subjects

J Durham

Publications and source records attributed to J Durham.

At least 37 records · Page 2Linked to original sources
PubMed1996

Exposure for laparoscopic cholecystectomy dissection adversely alters biliary ductal anatomy.

BACKGROUND: Exposure for open cholecystectomy entails lateral, caudal traction on the gallbladder infundibulum, which results in opening the angle between the cystic and hepatic ducts. Laparoscopic cholecystectomy (LC), as initially described, is done with cephalad traction on the gallbladder. We hypothesized LC exposure technique narrows the angle between the cystic and hepatic ducts, placing them at increased risk of injury. METHODS: Twenty-three patients had routine LC. Cystic duct cholangiography (IOC) was done with a flexible 5-Fr catheter via a percutaneous introducer placed anterior to the gallbladder. Exposure of Calot's triangle was maintained with cephalad traction on the gallbladder fundus. IOC was repeated after allowing the organ to assume the anatomic position. The cholangiograms were inspected for significant differences, and the angle of the cystic to the hepatic duct (CDHD) was measured by a blinded radiologist. RESULTS: The mean angle of the cystic to hepatic duct was 30 degrees +/- 19 degrees in the IOCs taken with cephalad traction on the gallbladder fundus vs 59 degrees +/- 22 degrees, P < 0.001, in the cholangiograms taken without traction. A filling defect at the cystic-hepatic duct junction was present in 39% of IOC taken with traction vs none without traction. The intrahepatic ducts were seen in all films without traction, whereas the intrahepatic ducts were not visualized in 13% of IOCs taken with traction. CONCLUSIONS: From these data we conclude (1) extra-hepatic biliary ducts may be at increased risk of injury during LC because of the exposure technique and (2) imaging bile ducts in the anatomic position may convey misleading information about the relative location of important structures. Optimal exposure for dissection of Calot's triangle should utilize a second clamp on the infundibulum with lateral, caudal traction.

Bile Ducts, Intrahepatic↗
PubMed1996

Growth of single HL60 cells in liquid culture: analysis of the influences of differentiative agents.

Treatment of serum-free grown HL60 cells with certain combined amounts of retinoic acid (9-cis or all-trans RA) and 1 alpha 25 dihydroxyvitamin D3 (D3) results in differentiation of 71-77% of cells towards either neutrophils or monocytes. Studies of the differentiation of HL60 cells in flask cultures does not reveal: (i) the extent to which selective growth of cells might have occurred; and (ii) the overall level of cell survival. This information can be obtained by monitoring the effects of differentiative agents on individual cells. Serum-free grown HL60 cells were cultured as single cells in microtitre wells in conditioned medium obtained from exponentially growing and serum-free cultures of HL60. This resulted in a cloning efficiency of 85% and HL60 cells doubled every 24 h. During a period of exponential growth < 0.5 to 2% of the cells generated died. Single HL60 cells were treated with 9-cis and all-trans RA (5 x 10(-7) M) together with a small amount of D3 (3.9 x 10(-14) M) to promote neutrophil differentiation. D3 alone (10(-7) M) and D3 (5 x 10(-9) M) in combination with 9-cis RA (10(-8) M) were used to promote monocyte differentiation. The growth kinetics of HL60 cell cultures that were differentiating to neutrophils and to monocytes were similar. Single-cell experiments have revealed that: (i) differentiating HL60 cells undergo a variable number of divisions (two to five) prior to arresting their growth; and (ii) up to 33% of the cells that are generated (by day 5) die. Seventy to eighty per cent of the cells in each of the wells had matured. These findings have important implications in regard to whether retinoids and D3 provide signals that determine the choice of maturation pathway or that merely facilitate selective survival and/or expansion of cells that have independently determined their differentiation fates.

Cell Differentiation↗
PubMed1995

Assessment of compliance with home cardiorespiratory monitoring in infants at risk of sudden infant death syndrome. Collaborative Home Infant Monitoring Evaluation (CHIME).

OBJECTIVES: Documented monitoring was used to evaluate prospectively (1) the level of compliance among infants in whom cardiorespiratory monitoring was clinically indicated and (2) factors that might influence compliance: diagnosis, socioeconomic status, maternal age and education, and alarms. STUDY DESIGN: Sixty-seven infants (51% female, 49% term) were sequentially enrolled, and monitoring was prescribed for the following indications: siblings of sudden infant death syndrome victims (16%), apnea of prematurity (45%), and apparent life-threatening events or apnea of infancy (39%). Demographic data, alarm and event data, and a summary report of monitor use from the first monitor download were obtained. RESULTS: Maternal age, education, and insurance status did not differ significantly by indication for monitoring. The median number of monitor alarms per 10 hours of use was 0.7 for apnea or bradycardia and 0.6 for loose lead alarms. Monitors were available for use in the home from 2 to 106 days (median, 11 days). Median hours of monitor use per full day in the home was 15.5 hours. Of 67 infants, 58 used the monitor for at least part of every day in the home. The number of hours of monitor use per day did not differ significantly by diagnostic category, chronologic age, alarms, maternal age, education, or insurance type. This study population of infants at increased risk of sudden infant death syndrome had excellent compliance; 75% of the infants were monitored more than 10.5 hours per day, and 25% were monitored more than 21 hours per day. CONCLUSIONS: Documented monitoring provides an objective measure of compliance. These data provide a potential goal for level of compliance with home cardiorespiratory monitoring.

Analysis of Variance↗
PubMed1995

Particular combinations of signals, by retinoic acid and 1 alpha, 25 dihydroxyvitamin D3, promote apoptosis of HL60 cells.

The promyeloid cell line HL60, when grown in serum-free medium, is induced to differentiate towards either neutrophils or monocytes by treatment with particular concentrations of 9-cis retinoic acid (9-cis RA) and 1 alpha, 25 dihydroxyvitamin D3 (D3). We have investigated whether treatment of HL60 cells with 9-cis RA and D3 can lead to growth arrest and a failure to undergo cell differentiation. This occurred in two circumstances and HL60 cells died rapidly by apoptosis. First, treatment with 5 x 10(-7) M 9-cis RA and 1.25 x 10(-9)-3.1 x 10(-10) M D3 promoted growth arrest and apoptosis of HL60 cells. The amount of 9-cis RA alone promoted significant neutrophil differentiation of HL60 cells. The amounts of D3 alone promoted a very low level of monocyte differentiation. Treatment with each agent alone did not result in increased levels of apoptosis. Second, HL60 cells were treated with concentrations of 9-cis RA (5 x 10(-7) M) and D3 (3.9 x 10(-14) M) that were appropriate for induction of neutrophil differentiation. At the time when they were undergoing commitment to the neutrophil pathway of differentiation (days 1-2), an amount of D3 (1 x 10(-7) M) that promotes monocyte differentiation was added to the cultures. HL60 cells failed to differentiate and died by apoptosis. Hence, certain combinations of signals, elicited by 9-cis RA and D3, promote apoptosis of HL60 cells. This finding has important implications for the use of retinoids and D3 in differentiation therapy.

Apoptosis↗
PubMed1994

Indomethacin potentiates the induction of HL60 differentiation to neutrophils, by retinoic acid and granulocyte colony-stimulating factor, and to monocytes, by vitamin D3.

We have confirmed previous observations that HL60 cells treated with a combination of 10 nM retinoic acid (RA), and 30 ng/ml granulocyte colony-stimulating factor (G-CSF) differentiate efficiently towards neutrophils, as characterized by their growth arrest and acquisition of phagocytic ability. Such low concentrations of RA alone provoked only a small proportion of HL60 cells to differentiate, and G-CSF alone provoked no differentiation. In the presence of 30 microM indomethacin (an inhibitor of the enzyme cyclooxygenase that catalyses the first step of prostanoid synthesis), the onset of differentiation provoked by RA plus G-CSF was more rapid, but the final proportion of mature cells was unchanged. Indomethacin also potentiated the growth arrest and differentiation of cells in response to 10 nM RA alone. Although the potentiating effect of indomethacin on RA-induced differentiation occurred at several indomethacin and RA concentrations, it was only apparent when the RA concentration used was alone sufficient to induce a small proportion of cells to differentiate. Indomethacin shifted the G-CSF dose-response curve of cells treated with 10 nM RA to lower G-CSF concentrations. 1 alpha,25-dihydroxy vitamin D3 (VitD3) induces HL60 cells to differentiate to monocytes and indomethacin also potentiated the differentiation of HL60 cells in response to low doses of VitD3 5,8,11-eicosatriynoic acid, an inhibitor of 5-lipoxygenase and 12-lipoxygenase, neither potentiated neutrophil differentiation of HL60 cells, nor prevented indomethacin potentiation of the differentiation of RA-primed cells. Treatment of cells with dexamethasone, a steroid whose effects include inhibition of arachidonate mobilization by phospholipase A2, potentiated RA-primed neutrophil differentiation in a manner similar to indomethacin. These observations suggest that an arachidonate metabolite formed downstream of cyclooxygenase suppresses differentiation of HL60 cells both to neutrophils and monocytes, probably by inhibiting some event essential to commitment to differentiation.

Arachidonic Acid↗
PubMed1993

Chopart amputation with percutaneous heel cord lengthening.

When amputation becomes necessary in a patient with peripheral vascular disease, it is important to preserve as much tissue as possible to preserve maximum function. This is especially important because the other extremity may have similar involvement in the future. With appropriate care, an amputation at the Chopart (calcaneocuboid-talonavicular) level can give a good functional result.

Achilles Tendon↗
PubMed1992

Protein kinases and the androgen-induced proliferation of accessory sex organ smooth muscle.

The possible role of second messenger systems in androgen-dependent smooth muscle proliferation was investigated. Focusing on the hormone-sensitive guinea pig seminal vesicle, we analyzed changes in protein kinase C (PKC) and cAMP-dependent type I and II protein kinases during the androgen-dependent smooth muscle proliferation of puberty, as well as in the transition to the nonproliferative state of the adult. The androgenic sensitivity of the cAMP-dependent type I and II protein kinases and the cAMP-dependent phosphorylations of soluble muscle proteins did not correlate with the qualitative change in the androgenic sensitivity of the prepubertal vs. adult animals. In contrast to the cAMP-dependent protein kinases, regulation of the soluble and particulate forms of PKC corresponded to the androgen-induced smooth muscle proliferation. That is, in the seminal vesicle muscle of prepubertal castrated animals, androgen treatment reduced both the soluble and particulate forms of PKC during the increase in smooth muscle DNA synthesis, and in adult seminal vesicle smooth muscle, which was resistant to androgen-induced proliferation, both forms of the enzyme were resistant to androgenic stimulation. It is concluded that PKC may be a component of an autocrine mitogenic mechanism involved in the coupling and uncoupling of androgen-induced smooth muscle proliferation.

Androgens↗
PubMed1992

Compartment pressures of the leg following intramedullary fixation of the tibia.

A prospective study was performed to determine whether compartment pressures of the leg were affected by intramedullary fixation of the tibia. Ten of the 11 patients studied had surgery for acute diaphyseal fractures and 1 for tibial nonunion. Compartment pressures were measured immediately prior to the procedure and at 12 hours after the procedure. There was no difference between the preoperative and postoperative compartment pressures. Our data suggest that intramedullary stabilization of the tibia does not predictably increase compartment pressures.

Adolescent↗
PubMed1991

A virus-particle vaccine prepared from bovine mammillitis virus against herpes genitalis.

A vaccine against herpes genitalis was prepared from the extracellular virus particles from baby hamster kidney cells infected with bovine mammillitis virus (BMV) strain "Allerton". The virus was inactivated by formaldehyde followed by ultracentrifugation to concentrate the virus particles and eliminate formaldehyde to an acceptable concentration for immunisation of human subjects. The vaccine was cross antigenic and cross immunogenic with herpes simplex virus type 1. Thirty-four consorts at high risk of herpes genitalis were immunised with two or three doses each containing 10(9) virus particles equialent to approx. 150 micrograms protein. There has been no evidence of local or general side effect in a follow-up period of over 100 patient years. The immunogenicity and protective efficacy of this vaccine in human subjects will be investigated in a double-blind placebo-controlled trial.

Adult↗
PubMed1990

General practitioners' ability to predict outcome for elderly patients admitted to acute medical beds.

This study investigated general practitioners' expectations about the management of their elderly patients following admission to acute medical beds. They were asked to predict the length of stay, main type of hospital care and outcome of the admission. There was very poor agreement between the predicted and the observed length of stay, type of care and outcome. The general practitioners underestimated the length of stay and severity of outcome, and overestimated the amount of acute medical intervention patients would receive in hospital. These results suggest that there is an urgent need to improve the level of communication between general practitioners and secondary care services.

Aged↗
PubMed1990

Alternatives to the admission of some elderly patients to acute medical beds.

There is evidence that admission to an acute medical ward is not the best way to look after many elderly patients. This study investigated 83 general practitioners' preferences for the management of 200 elderly patients admitted to the medical beds at Wellington Hospital. For 63.5% of the patients this admission had been by their own doctor and 84% of these patients had been cared for by this doctor for longer than one year. Admission to an acute medical bed was the preferred option for only 48% of patients. Augmented home care was considered a possible option for 31.5% of patients but was mentioned as one of the preferred options for only 9.0%. Admission to a general practitioner bed was the preferred option for 16.5% of patients. The results of this study suggest that area health boards should provide more choices for the management of acute illness in elderly patients.

Aged↗
PubMed1990

The natural history of intimal flaps in a canine model.

The natural history of arterial intimal flaps has not been well defined. This study characterizes the natural history of unrepaired intimal flaps. Thirty-nine 1-, 2-, and 3-mm hemispheric, distally based intimal flaps were made in 4- to 5-mm diameter canine femoral and carotid arteries. Twenty arteries had 2- and 3-mm intimal flaps and were monitored for short-term arterial thrombosis and flap extension. Nineteen had 1- and 2-mm intimal flaps and were monitored for thrombosis, long-term development of neointimal hyperplasia, arterial stenosis, and persistence of the flap. While 40% of the arteries with 3-mm intimal flaps developed thrombosis in 3 to 5 days, only 3% of the arteries with 1- or 2-mm intimal flaps developed thrombosis. Most 1- to 2-mm intimal flaps resolved and the subsequent development of neointimal hyperplasia or arterial stenosis was minimal. Arteries with hemodynamically significant stenoses from intimal flaps warrant repair, while arteries with smaller intimal flaps may not require repair.

Animals↗
PubMed1990

Effects of propylthiouracil on the biodistribution of an iodine-131-labeled anti-myeloid antibody in normal dogs: dosimetry and clinical implications.

Despite the use of near maximal doses of chemoradiotherapy, tumor recurrence remains the most frequent cause of treatment failure following marrow transplantation for leukemia. We have previously demonstrated that it is possible to selectively deliver radiation to the marrow space. In that study an initial short half-life of the radionuclide was observed. In this study we attempted to prolong the retention of the radioiodine in marrow through the use of propylthiouracil (PTU). When administered to normal dogs, PTU pretreatment resulted in improved marrow localization of 131I-labeled DM-5. There was no appreciable loss of activity from the marrow during the 2-4 hr postinjection time interval; a finding in contrast to the control animals where marrow activity declined a mean 45 +/- 0.5% over the same time period. Additionally, in contrast to controls, a rise in plasma trichloroacetic acid (TCA) nonprecipitable activity was not demonstrated in the PTU treated group during this 2-4 hr period. These results suggest that PTU's inhibition of deiodinases resulted in longer residence time of the radionuclide in its target tissue without adversely affecting distribution to non-target organs.

Animals↗