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Biomedical subjects

F Harvey

Publications and source records attributed to F Harvey.

16 recordsLinked to original sources
PubMed2004

Influence of nutrient application rate on growth and rooting potential of the West African hardwood Triplochiton scleroxylon.

Effects of stock plant nutrition on growth and subsequent rooting of leafy stem cuttings of the commercially important west African tree Triplochiton scleroxylon K. Schum. were investigated to identify the primary morphological variables influencing adventitious root formation. Potted plants were watered as required with one of four balanced nutrient solutions (0, 15, 63 or 125 mg N l(-1)). Increasing the nutrient supply to stock plants increased growth rate and rate of adventitious root production of subsequently harvested cuttings, but an optimum nutrient regime was not identified. Rooting percentage increased from 27% in cuttings harvested from stock plants receiving a low nutrient supply to 64% for cuttings harvested from stock plants receiving eight times the amount of nutrients extractable from plants under typical field conditions in West Africa. The ability of a cutting to retain its leaf during propagation and the length of the cutting were the primary measured characteristics associated with rooting and accounted for 43% of the variance fitted in the model. The length of the new shoot, total leaf area and within-shoot position (node position) were also significantly associated with rooting. After these characteristics were fitted to the model, the genetic origin (clone) was not statistically significant. We conclude that genetic variation in rooting potential is mediated through variations in morphological and physiological traits, rather than through genetic variation in cell differentiation or related aspects of root initiation.

Malvaceae↗
PubMed2000

Prospective, randomized, double-blind study comparing single-agent antibiotic therapy, ciprofloxacin, to combination antibiotic therapy in open fracture wounds.

OBJECTIVE: The purpose of this study was to compare the efficacy of a single agent, ciprofloxacin, with that of combination antibiotic therapy consisting of cefamandole and gentamicin in all types of open fracture wounds. STUDY DESIGN: A prospective double-blind randomized clinical trial. SETTING: A Level 1 trauma center. PATIENTS: One hundred ninety-five consecutive patients with 203 open fractures were enrolled over a twenty-month period. Twenty-nine fractures from low-velocity gunshot wounds were excluded, and three other patients were excluded because of protocol violations. Our final number of patients were 163, with 171 open fractures. MAIN OUTCOME MEASUREMENT: The infection rates for Type I and Type II open fractures for both antibiotic groups were calculated. The infection rate of Type III open fractures for both antibiotic groups was also calculated. Chi-square analysis with Yates correction was used to assess statistical significance of two treatment groups. RESULTS: The infection rate for Types I and II open fractures in the ciprofloxacin group was 5.8 percent and 6 percent for the cefamandole/gentamicin group (p = 1.000). The infection rate for Type III open fractures for the ciprofloxacin group was 31 percent (8 of 26) versus 7.7 percent (2 of 26) for the cefamandole/gentamicin group (p = 0.079). There were no statistically significant differences in infection rate between the group treated with ciprofloxacin and that treated with cefamandole/gentamicin for Types I and II open fracture wounds. However, there appeared to be a high failure rate for the ciprofloxacin Type III open fracture group, with patients being 5.33 times more likely to become infected than those in the combination therapy group. Although this difference was not statistically significant, possibly because of the small sample size, there was a definite trend toward statistical significance. CONCLUSION: Single-agent antibiotic therapy with ciprofloxacin is effective in treatment of Type I and Type II open fracture wounds. However, on the basis of our results, we cannot recommend ciprofloxacin alone for Type III wounds. Possibly one can use fluoroquinolones in combination therapy, specifically as an alternate to an aminoglycoside.

Adult↗
PubMed1998

Effect of low urine specific gravity on pregnancy testing.

Urine pregnancy tests performed at a large urban university student health center were examined for specific gravity to determine whether a low urine specific gravity, compared with a serum specimen, could alter the result of a urine pregnancy test. At the same time, a serum pregnancy test was performed on those samples with negative results and a specific gravity of less than 1.015. During the study period, 410 urine specimens were evaluated. Eighty of the women with a specific gravity under 1.015 had negative urine pregnancy tests with a concomitant serum specimen. The authors concluded that current sensitive immunoassay tests for human chorionic gonadotropin (HCG) are highly sensitive and that low specific gravity does not appear to alter this sensitivity.

Bias↗
PubMed1996

A prospective study of carbon dioxide-digital subtraction vs standard contrast arteriography in the evaluation of the renal arteries.

OBJECTIVE: To compare carbon dioxide-digital subtraction arteriographic (CO2-DSA) images of renal artery anatomy with standard iodinated contrast arteriographic (ICA) images. DESIGN: One hundred patients with vascular disease who required abdominal aortography were evaluated by both CO2-DSA and ICA modalities. Two blinded readers interpreted arteriograms for the degree of renal artery stenosis, and a third reader was employed to resolve differences in reader interpretations. SETTING: University medical center. MAIN OUTCOME MEASURES: The sensitivity, specificity, negative predictive value, positive predictive value, and accuracy were calculated for the ability of CO2-DSA to demonstrate a 60% or greater stenosis of the main renal artery; kappa values for CO2-DSA and ICA were calculated to assess intraobserver variability. RESULTS: Of the 200 main renal arteries imaged, 17 (9 by means of CO2-DSA), 8 means of ICA) were eliminated because of inadequate visualization of the renal artery. In identifying a renal artery stenosis of 60% or greater, CO2-DSA had a sensitivity of 0.83, specificity of 0.99, positive predictive value of 0.94, and negative predictive value of 0.98. The overall accuracy was 0.97. The kappa was 0.75 for CO2-DSA and 0.70 for ICA, hence, the variation in the interpretations of CO2-DSA and ICA were comparable. CONCLUSION: Images by means of CO2-DSA accurately reflect pathologic changes in renal arteries and are thus useful in the diagnosis of clinically occult occlusive renal artery disease in patients at risk of contrast medium-related nephrotoxicity.

Adult↗
PubMed1996

Syme amputation: results in patients with severe forefoot ischemia.

Since 1980, 35 patients (age range 40-77 years) with severe forefoot ischemia have undergone a unilateral Syme amputation. Thirty-one patients (89%) were diabetic. The indication for amputation was either extensive forefoot gangrene or ulceration too advanced for a digital or transmetatarsal amputation. Twenty-two amputations (63%) were immediately preceded by either percutaneous transluminal angioplasty (four) or a bypass procedure to the popliteal artery (five) or an infrapopliteal artery (13). Primary healing occurred in 19 (86%) of 22 amputations immediately preceded by revascularization and in 10 (77%) of 13 limbs undergoing amputation alone. Twenty-eight (97%) of the 29 patients with successful primary healing were successfully rehabilitated. Rehabilitation rendered 13 patients fully ambulatory, 15 ambulatory with intermittent use of a walker or cane and one unable to walk. At follow-up of four months to 13 years (mean 42 months), the cumulative ambulatory rate at 1, 3, and 5 years was 92, 80 and 80%, respectively. Syme amputation allows a return to a functional ambulatory status in a high percentage of patients with severe forefoot ischemia. These findings suggest that Syme amputation is an acceptable option in dysvascular patients with severe forefoot ischemia.

Adult↗
PubMed1991

Fungal infection: a common, unrecognised complication of acute liver failure.

The true incidence and clinical relevance of fungal infection was ascertained in a prospective study of 50 consecutive patients with acute liver failure. Fungal infection was present in 16 (32%) patients (15 candida, one aspergillus) and in seven was considered the major cause of death. All six untreated died, while five of ten patients treated with anti-fungal therapy survived. The diagnosis was made on positive cultures from at least one significant site or on histological evidence of tissue invasion. All 16 had concomitant bacterial infection and shared features suggestive of a clinical syndrome: deterioration in coma grade after initial improvement; pyrexia unresponsive to antibiotics; established renal failure; and a markedly elevated white cell count. Fungal infection is a common, serious complication of acute liver failure and therapy is indicated for those with positive cultures. A prophylactic trial would be justified in those surviving 5 days, especially, with established renal failure.

Acute Disease↗
PubMed1990

Prospective study of bacterial infection in acute liver failure: an analysis of fifty patients.

Fifty consecutive patients admitted with acute liver failure, minimal grade II encephalopathy, were studied prospectively to determine the incidence, timing and cause of bacterial infection, the relationship to clinical criteria for infection; and the influence of early microbiological diagnosis on clinical outcome. There were 53 proven bacterial infections in 40 patients, whereas in 5 of the remaining 10 patients infection was suspected on clinical grounds in the absence of significant cultures. Seven patients (14%) had more than one bacterial infection, and four patients had simultaneous infections caused by different organisms at each site. Fourteen infections (26.4%) were associated with bacteremia, and in six of these no source was found. Twenty-five infections (47.1%) arose from the respiratory tract, 12 (22.6%) from the urinary tract and 2 (3.7%) from central venous cannulas. Thirty-seven (69.8%) of the 53 infections were due to gram-positive bacteria; Staphylococcus aureus accounted for 19 (35.8%) of all the infections. Thirty patients died (60%), 28 of whom had bacterial infection at some time; in 24 of these the infection was diagnosed less than 24 hr before death. All nine deaths that occurred more than 7 days after admission were directly attributable to microbial infection. Clinical features such as elevated temperature and elevated peripheral white blood cell count were poor indicators of bacterial infection because these were absent in 30.2% of cases. These data show that there is a high incidence of bacterial infection early in the course of acute liver failure and suggest that prophylactic antimicrobial therapy, although unproven, might be justified.

Acute Disease↗
PubMed1988

Cytomegalovirus infection and donor/recipient HLA antigens: interdependent co-factors in pathogenesis of vanishing bile-duct syndrome after liver transplantation.

The contribution of cytomegalovirus (CMV) infection and its interrelation with HLA antigens in the development of chronic rejection (vanishing bile-duct syndrome--VBDS) was investigated in 101 patients surviving for at least 3 months after liver transplantation. A 1-2 antigen match for HLA DR antigens (30.9% vs 4.5% for zero DR match; p less than 0.002), a zero match for HLA A/B antigens (27.5% vs 10.9% for 1 or more A/B match; p less than 0.05), and active CMV infection (26.3% vs 4.4% for no CMV infection; p less than 0.005) were independently associated with an increased risk of VBDS. The coexistence of a 1-2 HLA DR match and CMV infection carried the highest relative risk (10.1) of VBDS; these two variables were probably interdependent since either alone was associated with a low relative risk (0.45 and 0.5). The association between VBDS and active CMV infection was not a consequence of alterations in immunosuppressive therapy. The findings would be consistent with precipitation of chronic rejection by CMV-induced HLA antigen expression in patients rendered susceptible by the donor/recipient HLA antigen match.

Adolescent↗
PubMed1985

Spinal cord contusion in the rat: production of graded, reproducible, injury groups.

A weight drop technique was used to produce a contusive injury of the spinal cord in the rat. A restricted laminectomy was carried out at T8 and the spinal column stabilized by clamps attached to the spinous processes of adjacent vertebrae. A 2.4-mm-diameter impounder was lowered onto the dura and a 10-g weight dropped 0.0, 2.5, 5.0, 7.5, 10.0, or 17.5 cm onto the impounder. The functional deficit was assessed for 4 weeks after injury and the spinal cord tissue processed for histopathologic analysis. The results indicated that groups of rats (N = 10) subjected to the weight dropped from increasing heights exhibited a graded final functional deficit as measured by scores on a modified Tarlov scale or the mean angle attained in the inclined plane test of Rivlin and Tator. Histopathologic results also indicated the production of graded lesions. Three groups of experimental animals were statistically distinguished corresponding to those with mild, moderate, or severe final functional deficit. The average functional deficit in these injury groups, produced by dropping the weight 2.5, 5.0, or 17.5 cm, respectively, was reproducible in replicate experiments. This model of spinal cord contusion in the rat may be useful in screening putative therapeutic drug regimens for subsequent clinical trials on different groups of patients with spinal cord injury.

Animals↗
PubMed1977

Species differences in the hepatic microsomal oxidation of nalidixic acid.

The kinetics of the conversion of nalidixic acid to the 7-hydroxymethyl derivative (M-HNA) by isolated liver microsomes of several common laboratory animal species was studied under optimal conditions. The order of activity was (from greatest activity to least): monkey greater than rabbit greater than mouse greater than rat greater than dog greater than cat. The formation of 7-HNA followed apparent Michaelis-Menton kinetics in all species except the cat; the substrate concentration at half-maximal velocity was highest with mouse microsomes, while the maximum velocity was greatest with monkey microsomes. Cat, dog, mouse and rabbit microsomes formed an additional metabolite, which was identified as 6-hydroxynalidixic acid, 1-ethyl-1,4-dihydro-6-hydroxy-7-methyl-4-oxo-1,8-naphthyridine-3-carboxylic acid (6-HNA); in the cat, this was the major microsomal metabolite.

Animals↗