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Biomedical subjects

R J Allen

Publications and source records attributed to R J Allen.

At least 37 records · Page 2Linked to original sources
PubMed1994

Strategies for establishing a critical care obstetric service.

Critical care obstetrics is gaining increased recognition as a subspecialty of perinatal medicine. As the specialty continues to expand, many institutions may consider establishing a critical care obstetric service. However, implementing such a service is not feasible for every institution because of space limitations, budgetary constraints, lack of necessary resources, and/or a limited number of critically ill obstetric patients. This article explores strategies for examining the feasibility of establishing a critical care obstetric service, suggests methods of implementation, and offers an alternative when establishing a critical care obstetric service is not feasible.

Feasibility Studies↗
PubMed1994

The latissimus dorsi/scapular bone flap (the "latissimus/bone flap").

During the past 4 years, our trauma and reconstructive service has treated a number of patients with lower extremity trauma involving the loss of both soft tissue and significant segments of tibia. While there are many methods for reconstruction of such defects, we became interested in providing a one-stage reconstruction of both the soft tissues and the missing bone segments. Since our standard flap for lower extremity reconstruction is a latissimus dorsi flap, we became interested in transferring a portion of the lateral border of the scapula along with the latissimus muscle. We dissected 34 cadaver scapulas in order to verify the reliability of the blood supply to the lateral border of the scapula based on the thoracodorsal artery. We then performed 12 "latissimus/bone flaps" from 1988 to 1992. Prior to flap transfer, control of the wound was obtained with surgical debridement and aggressive wound management. The flap usually was performed 5 to 7 days after initial contact with the patient. The muscle was skin grafted. All patients reported are ambulating, with x-ray evidence of bony incorporation of the transferred bone segment into the tibia. We feel that inclusion of the lateral scapula bone with the latissimus dorsi is a useful adjunct in the management of lower extremity trauma.

Adolescent↗
PubMed1994

MRI characterization of cerebral dysgenesis in maternal PKU.

MPKU pregnancies, with or without dietary treatment to reduce maternal plasma phenylalanine (phe), show variable, increased non-physiologic levels, as the putative cause of fetal teratogenicity. Cerebral dysgenesis with clinical neonatal microcephaly and congenital heart disease indicates altered organ morphogenesis. Although there is not an established precise relationship between maternal phe levels and outcome, dietary restriction before or early in gestation is universally advised. Both human experience and animal research have suggested differential organ responses to high and low phe levels. Structural microencephaly may be due to reduced brain volume or abnormal regional brain development. Infants in MPKU are also at risk to develop PKU. Microencephaly was evident by MRI in 8 of 21 infants born to 12 MPKU mothers; 2 infants of one mother developed PKU. All levels of gestational plasma phe were associated with otherwise structurally normal infant microencephalic brains appropriate for age in myelination. CHD occurred in one microencephalic infant of a classic MPKU treated in the first trimester. Maternal, cord and neonatal plasma phenylalanine at delivery did not correlate with teratogenic effects. Only untreated 'classic' MPKU fetal effects appear predictable.

Abnormalities, Multiple↗
PubMed1993

Impact of repackaging hazardous (infectious) hospital waste on the indoor air quality of a hospital.

With landfill bans on the disposal of hazardous (infectious) hospital wastes, many hospitals in the United States are faced with selecting alternative means of disposal. One alternative method of disposal is to repackage the waste and ship it off site for incineration. This paper reports on a study in which airborne bacteria were sampled in an area where waste was repackaged. Results of the sampling showed bacteria concentrations ranging from not detectable (central supply room) to 105 colonies/m3 air (approximately 40 feet from the incinerator room door). This would seem to indicate that the source of the bacteria was at or near the incinerator room door where the repackaging operation took place. Although some human pathogens were identified, most of the bacteria identified do not represent a serious health threat. However, Staphylococcus aureus was found in air samples collected from locations in the hospital served by the same ventilation system in the area of the repackaging operation. The waste handling practices used in hospitals need to be reevaluated, and the definition of 'sick building syndrome' needs to be expanded beyond chemicals to include microorganisms. More research is needed to characterize bacteria in air and to determine the impact of airborne bacteria on human health.

Air Microbiology↗
PubMed1993

A reversed digital artery island flap for the treatment of fingertip injuries.

A series of complex fingertip injuries managed with a reversed digital artery island flap is presented. An island of skin on the side of the proximal phalanx can be elevated on a digital arterial pedicle and rotated to the fingertip to provide abundant skin and subcutaneous coverage for acute or chronic deficits. The flap receives retrograde flow from its ipsilateral digital artery after passage through dorsal and palmar vascular plexuses at the middle and distal phalangeal level. Thirteen flaps were performed on eleven patients with no loss of any portion of the flap. The advantages of this procedure include a reconstruction that necessitates surgery only on the injured digit, allowing for the treatment of single or multiple fingertip injuries that provides functional sensation in the reconstructed fingertip without causing loss of motion.

Adolescent↗
PubMed1993

Effect of pregnancy on the vasodepressor response to atrial natriuretic factor.

OBJECTIVE: We attempted to determine whether pregnancy alters the vasodepressor response to both physiologic and pharmacologic infusions of atrial natriuretic factor 99-126. STUDY DESIGN: Ten virgin and 10 pregnant (17 +/- 1 days of gestation) conscious, unrestrained Sprague-Dawley rats with chronic indwelling vascular catheters were studied. Mean arterial pressure and heart rate were measured in response to steady-state infusions of either saline solution or increasing concentrations of atrial natriuretic factor (range 5 to 2560 ng.kg-1.min-1). RESULTS: Basal mean arterial pressure was significantly lower in pregnant rats than in virgin rats (89 +/- 3 vs 97 +/- 2 mm Hg, p < 0.02). Atrial natriuretic factor induced significant dose-dependent decreases in mean arterial pressure and heart rate in virgin and pregnant rats (p < 0.001). The hypotensive effects of atrial natriuretic factor were blunted in the pregnant rats only in response to the highest concentrations of atrial natriuretic factor administered (-27 +/- 3 mm Hg in pregnant rats vs -43 +/- 3 mm Hg in virgin rats, p < 0.005). CONCLUSIONS: The vasodepressor response to physiologic infusions of atrial natriuretic factor was not affected by pregnancy status. However, pharmacologic infusions of atrial natriuretic factor resulted in a blunted vasodepressor response in the pregnant animals. This may be due to alterations in vascular atrial natriuretic factor receptors, changes in the clearance rate of atrial natriuretic factor, or the modulating effects of other vasoactive hormones.

Animals↗
PubMed1993

A comparison of the laser flare cell meter and fluorophotometry in assessment of the blood-aqueous barrier.

PURPOSE: To evaluate and compare the use of the Kowa laser flare cell meter and intravenous anterior chamber fluorophotometry in assessment of the blood-aqueous barrier after cataract surgery. METHOD: Laser flare and cell measurements and fluorophotometry were performed at 1 and 3 months after surgery in 48 eyes of 44 patients admitted for routine cataract surgery. The fellow pseudophakic eyes of these patients were used as controls. RESULTS: The two techniques measure different parameters, but both methods are able to document the integrity or breakdown of the blood-aqueous barrier. However, the laser flare cell meter is more sensitive in quantifying subtle changes in barrier function to large molecules (proteins). Various methods of assessing anterior chamber fluorophotometry data were also compared. Measurement of a diffusion coefficient (requiring the measurement of plasma fluorescence) was not found to be more sensitive than other methods and did not alter the clinical significance of data obtained from the measurement of anterior chamber fluorescence alone. CONCLUSIONS: Both the laser flare cell meter and fluorophotometry provide a method for the assessment of the postoperative blood-aqueous barrier. However, the laser flare cell meter is rapid, noninvasive, and relatively easier to use. Therefore, for clinical use, it has great practical advantages over fluorophotometry.

Adult↗
PubMed1991

Referrals for vascular hypertension in a group of 45-64-year-old patients.

Two hundred and ten consecutive 45-66-year-old patients underwent a routine eye examination and a decision was made whether to refer each patient on the basis of fundus appearance and other non-sphygmomanometric criteria. Blood pressure was then measured and the referral decision was reviewed. Of the 33 (15.7%) patients finally referred, only 5 (2.4%) would have been referred on the non-sphygmomanometric findings. It is suggested that optometrists include a protocol of blood pressure measurement as part of the eye examination routine.

Blood Pressure Determination↗
PubMed1990

Medicinal leeches: once again at the forefront of medicine.

Medical grade leeches have recently been used in the management of acute problems relative to venous congestion in patients with traumatic injuries and surgical problems. Specific cases, especially in the realm of reconstructive microsurgery, have demonstrated the effectiveness and application of leech therapy. Specific contraindications include arterial insufficiency from either anatomic or mechanical obstruction. We present five illustrative cases of successful therapeutic intervention.

Acute Disease↗
PubMed1989

Emission of airborne bacteria from a hospital incinerator.

Only five studies have been found in the literature which provide any indication of the effectiveness of incineration for rendering infectious hospital waste innocuous. Although there is an indication from these studies for release of bacteria in stack gas, none of the studies identified the bacteria or determined the source of bacteria. The purpose of the present study was to investigate the potential for a hospital incinerator to release human pathogenic bacteria into the ambient environment. In this study, waste spiked with Bacillus subtillis was burned in a hospital incinerator. Although bacteria were found in the incinerator stack gas, (concentrations ranged from not detectable to 1157 colonies/m3 of air) no Bacillus subtilis was recovered from the stack gas. The results suggest that the source of the stack gas bacteria was not from unburned waste or from outdoor air. Analysis of samples of air from the incinerator room (not simultaneous with the stack gas samples) indicates that the source of the stack gas bacteria was most likely the combustion air.

Air Microbiology↗
PubMed1989

Proper planning reduces risk in new technology acquisition.

In an environment of limited resources and increased risk and competition, financial managers must determine which new technologies will have the most benefit for a healthcare organization's long-term interests. Adapting a 12-step business planning approach to the evaluation process for new technologies offers organizations a comprehensive method that ensures accountability, confidence, and support for the acquisition.

Capital Expenditures↗
PubMed1985

Valproic acid toxicity.

Explore the source record for details and available documents.

Chemical and Drug Induced Liver Injury↗
PubMed1984

Determination of pantothenic acid in multivitamin pharmaceutical preparations by reverse-phase high-performance liquid chromatography.

A high-performance liquid chromatographic procedure was developed for the analysis of calcium pantothenate in nutritional supplements. The method involves a simple extraction using phosphate buffer and sonication. Chromatographic separation is obtained using an aminopropyl-loaded silica gel column in the reverse-phase mode. A UV detector set at 210 nm was used to monitor the effluent. Quantitative recoveries were obtained, and precision of the method is discussed. The method is applicable to multivitamin tablets, calcium pantothenate raw material, and yeast grown in the presence of high levels of calcium pantothenate. The results of the method are compared with results obtained from the USP microbiological method of analysis. It was concluded that the procedure is rapid, accurate, easily automated, and practical for routine quality control use.

Chromatography, High Pressure Liquid↗
PubMed1983

Biotinidase deficiency: the enzymatic defect in late-onset multiple carboxylase deficiency.

Late-onset multiple carboxylase deficiency is characterized clinically by skin rash, alopecia, seizures and ataxia and occasionally by candidiasis and developmental delay. Biochemically, these individuals exhibit findings consistent with a combined deficiency of the biotin-dependent carboxylases. We have found that the activity of the enzyme biotinidase is also deficient in the sera of five affected children (0 to 3% of mean control activity, 5.80 +/- 0.89 nmol X min-1 X ml-1 serum), and believe that it represents the primary biochemical defect in this disease. Biotinidase catalyzes the removal of biotin from the epsilon-amino group of lysine, through which biotin is covalently bound to the four known human carboxylases, thereby regenerating biotin for reutilization. The deficient activity in our patients was not due to an inhibitor, particularly biotin. It is also not a consequence of feedback control in affected individuals under treatment with pharmacologic doses of biotin. The biotinidase activities of the parents of those children who were available for study were intermediate between deficient and normal values (46% to 65% of mean normal activity). Children lacking biotinidase activity are unable to recycle biotin, and are thus entirely dependent upon exogenous biotin to prevent deficiency. Our findings indicate that the primary biochemical defect in late-onset multiple carboxylase deficiency is in biotinidase activity which is inherited as an autosomal recessive trait.

Amidohydrolases↗