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Biomedical subjects

R Warren

Publications and source records attributed to R Warren.

At least 19 recordsLinked to original sources
PubMed1992

A comparative study of imipenem versus piperacillin plus gentamicin in the initial management of febrile neutropenic patients with haematological malignancies.

Three-hundred and twelve episodes of fever in 234 neutropenic patients with haematological malignancies were treated empirically with either imipenem or a combination of piperacillin and gentamicin. There were no significant differences in the percentages of patients responding to therapy at either 72 h (59% and 56% of assessable episodes in the imipenem and combination groups respectively) or at the end of treatment (55% and 53% of assessable episodes in the imipenem and combination groups respectively). Patients in the piperacillin plus gentamicin group experienced significantly more renal tubular damage whereas those who received imipenem suffered more nausea or vomiting. We conclude that imipenem monotherapy represents an acceptable alternative to piperacillin plus gentamicin as empirical therapy of the febrile neutropenic patient.

Adolescent↗
PubMed1992

Improved method for the isolation and cultivation of human scalp dermal papilla cells.

We present an improved method for the isolation and cultivation of human scalp anagen hair follicle dermal papilla cells. Following treatment of the isolated dermal papilla with collagenase, incubation in Chang's medium mediates accelerated growth of the papilla cells when compared with other media such as DMEM, M199, and EMEM. Upon reaching confluency, the cells cultured in this fashion exhibit a multilayer-forming property that is dependent on normal proteoglycan synthesis. The papilla cells maintain this morphologic behavior for as long as 7 weeks in culture, or after being subcultured six times. During this time, the cells continue to synthesize extracellular matrix components associated with the human anagen follicle in situ. These include chondroitin sulfate, laminin, and type IV collagen. Type III collagen and keratan sulfate are poorly expressed by the papilla both in situ and in vitro. Heparan sulfate proteoglycan, a matrix component of the papilla in situ, is poorly expressed in vitro. Earlier reports suggested that the expression of extracellular matrix components is not maintained in culture. We show that the expression of these molecules is not dependent on the secondary culture medium, but continues in DMEM and M199 after primary culture in Chang's medium. Our results suggest that initial exposure of the dermal papilla to Chang's medium either selectively permits the outgrowth of papilla cells having extracellular matrix components similar to those found in situ, or stabilizes the expression of extracellular matrix components among the entire cultured cell population.

Cell Division↗
PubMed1992

Immediate and long-term results of percutaneous balloon aortic valvuloplasty: a report of 33 procedures.

The purpose of this study was to evaluate the immediate and long-term clinical and haemodynamic effects of Percutaneous Balloon Aortic Valvuloplasty (PBAV). Thirty-three procedures were performed in 27 patients, 11 males and 16 females with a mean age of 72 years. The peak to peak systolic gradient across the aortic valve decreased by 52%, from 67 +/- 24 mmHg to 31 +/- 15 mmHg (p < 0.0001) and the aortic valve area increased by 35%, from 0.48 +/- 0.16 to 0.67 +/- 0.21 cm2 (p < 0.001) after PBAV. There were no procedural deaths. Minor complications occurred in seven patients. Eighty-one per cent of patients (27 procedures) showed immediate symptomatic improvement, five remained symptomatic and one died in hospital before discharge. In a mean follow-up of 17 +/- 12 months (range six to 38 months), eight patients died due to congestive cardiac failure, six underwent repeat PBAV, three died due to noncardiac causes and three had recurrent symptoms controlled on medical therapy. Event free survival at 15 months was 43%. In conclusion PBAV produces a satisfactory immediate clinical and haemodynamic result, however, considering the high rate of symptom recurrence, this procedure has a beneficial role only in short-term palliation of severely symptomatic patients who are unable to undergo aortic valve replacement.

Actuarial Analysis↗
PubMed1992

Coronary-pulmonary artery fistula arising distal to obstructive coronary lesions.

We report 2 cases of coronary-pulmonary artery fistulae (CPF) arising distal to obstructive coronary artery disease. The fistula in the first patient was in the form of a tortuous dilatation of the distal portion of the right coronary artery and opened into the right pulmonary artery. In the second case, the fistula, a plexus of vessels, arose from the left anterior descending artery and entered the left pulmonary artery. Both the fistulae were successfully ligated at the time of concurrent coronary artery bypass graft surgery.

Aged↗
PubMed1992

Cleft lip repair using intramuscular hydroxyzine sedation and local anesthesia.

Intramuscular hydroxyzine was used alone for sedation in 18 cleft lip repairs with patients under 6 weeks of age. After injection of local anesthesia, the infants were quiet throughout the procedure. Blood pressure, pulse, respiration, and temperatures were normal throughout and the oxygen saturation remained above 94% in all cases. There were no complications noted with this series of patients and no patient required conversion to general anesthesia. Intramuscular hydroxyzine combined with local anesthesia and nerve block has been found to be a safe and effective method for cleft lip repairs in selected neonates under 6 weeks of age.

Anesthesia, Local↗
PubMed1992

Estimates of long-term immigration to the United States: moving US statistics toward United Nations concepts.

US immigration data are revised to reflect the UN demographic concept of long-term immigration. Long-term immigration is measured by the number of new immigrants (permanent resident aliens) arriving in the year, temporary migrant arrivals (nonimmigrants) who subsequently adjust to permanent resident status, arrivals of asylees and refugees, and nonimmigrants who arrive during the year and stay for more than twelve months before departing. The estimates of long-term immigration for 1983 are compared to official INS statistics on alien immigration. Significant differences emerge according to country of origin, age, and state of intended residence. A method of producing current estimates of long-term immigration is illustrated.

Age Factors↗
PubMed1991

Fibrosing mediastinitis with coronary artery involvement.

This case report describes a patient with chronic fibrosing mediastinitis involving the entire intrapericardial aorta, innominate artery, and the base of the heart with involvement of the proximal segments of the coronary arteries. This finding was unsuspected before emergency coronary artery bypass grafting. Coronary stenosis due to fibrosing mediastinitis is a rare complication of fibrosing mediastinitis. Owing to the extensive fibrosis, the normal bypass, cardiac preservation, and revascularization techniques required alteration and are discussed.

Coronary Disease↗
PubMed1991

Does tourniquet use during anterior cruciate ligament surgery interfere with postsurgical recovery of function? A review of the literature.

This article explores the issue of whether use of a tourniquet during arthroscopically assisted repair of the anterior cruciate ligament (ACL) slows the postoperative recovery of function. A tourniquet is customarily used to provide a bloodless field, thus enabling the surgeon to visualize the joint clearly. However, there is increasing evidence that tourniquets cause muscle and nerve damage that can have long-term consequences for the recovery of function following surgery. The two randomized trials that investigated tourniquet use during meniscectomy reached contradictory conclusions about the effects of the tourniquet. There have been no randomized trials of tourniquet use during the longer and more complex ACL surgery. This article reviews the pertinent literature and suggests some clinical implications of the available information.

Anterior Cruciate Ligament↗
PubMed1991

Age, sunlight, and facial skin: a histologic and quantitative study.

Quantitative methods were developed to assess the interrelation between age and sunlight on the facial skin of healthy women living in the same sunny area. The women were grouped into the following categories: young versus old and low versus high solar exposure. The features evaluated were perceived age, amount of facial wrinkling, skin color, and skin elasticity. A punch biopsy specimen of cheek skin was obtained and prepared histologically for evaluation of solar elastosis. The histologic examination was complemented by quantification of collagen and elastin by computer-assessed image analysis. Perceived age was estimated by untrained women viewing high quality photographs. As expected, those with greater sun exposure looked older and had more wrinkles, more severe elastosis, increased elastin, and decreased collagen.

Adult↗
PubMed1991

Specific syphilis serological tests may become negative in HIV infection.

The diagnosis of syphilis is frequently dependent upon the results of serological tests, but the reliability of syphilis serology in patients with HIV-1 infection has been questioned. We examined specific antibody to Treponema pallidum (TP) using the TP haemagglutination (TPHA) and fluorescent treponemal antibody-absorption (FTA-ABS) tests in AIDS patients and HIV-antibody-negative controls with a history of syphilis. Tests were carried out on two sera separated by an interval of at least 3 years from each patient. Twelve out of 29 AIDS patients compared with four out of 29 controls showed significant falls in titres of specific antibody as measured by the TPHA, FTA-ABS, or by both the TPHA and FTA-ABS (P = 0.02). Furthermore, in three out of 29 (10%) of the AIDS patients with past syphilis infections both the TPHA and FTA-ABS became non-reactive. We conclude that negative specific serology does not exclude a past syphilis infection in patients with AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Fasted state impedes recovery of porcine hepatic oxygen consumption after warm hepatic ischemia.

The most effective means to prepare the hepatic donor liver for harvest, preservation, and transplantation are not known. Studies have shown that in combination with an injury to the liver, fasting reduces hepatic function. This study randomized 20 market pigs, 20 to 45 kg, to an overnight fast (fed group) or a 42-hour fast (fasted group). Under general anesthetic perfusion of the portal vein and hepatic artery were controlled. Studies were performed at high flow (30 ml/min/kg portal flow and 10 ml/min/kg arterial flow) and after a 90-minute period of warm ischemia (no flow). Flow was restored at 25% of the original (low flow), then increased to 50% of the original (medium flow). After the ischemic insult, the fed group improved hepatic oxygen consumption at a faster rate than the fasted group (p less than 0.05 by ANOVA). In addition, significant differences were noted between the fed and fasted groups in the amount of insulin delivered by the portal venous system to the liver (p less than 0.001 by ANOVA). Hepatic oxygen consumption was related to insulin delivery (r2 = 0.46; p less than 0.001) for both groups. The data suggest that acute changes in the nutritional status of both the donor and the recipient may affect hepatic recovery from ischemia.

Amino Acids↗