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Biomedical subjects

J L Baker

Publications and source records attributed to J L Baker.

At least 19 recordsLinked to original sources
PubMed2006

Soil and surface runoff phosphorus relationships for five typical USA midwest soils.

Excessively high soil P can increase P loss with surface runoff. This study used indoor rainfall simulations to characterize soil and runoff P relationships for five Midwest soils (Argiudoll, Calciaquaoll, Hapludalf, and two Hapludolls). Topsoil (15-cm depth, 241-289 g clay kg(-1) and pH 6.0-8.0) was incubated with five NH4H2PO4 rates (0-600 mg P kg(-1)) for 30 d. Total soil P (TPS) and soil-test P (STP) measured with Bray-P1 (BP), Mehlich-3 (M3P), Olsen (OP), Fe-oxide-impregnated paper (FeP), and water (WP) tests were 370 to 1360, 3 to 530, 10 to 675, 4 to 640, 7 to 507, and 2 to 568 mg P kg(-1), respectively. Degree of soil P saturation (DPS) was estimated by indices based on P sorption index (PSI) and STP (DPSSTP) and P, Fe, and Al extracted by ammonium oxalate (DPSox) or Mehlich-3 (DPSM3). Soil was packed to 1.1 g cm(-3) bulk density in triplicate boxes set at 4% slope. Surface runoff was collected during 75 min of 6.5 cm h(-1) rain. Runoff bioavailable P (BAP) and dissolved reactive P (DRP) increased linearly with increased P rate, STP, DPSox, and DPSM3 but curvilinearly with DPSSTP. Correlations between DRP or BAP and soil tests or saturation indices across soils were greatest (r > or = 0.95) for FeP, OP, and WP and poorest for BP and TPS (r = 0.83-0.88). Excluding the calcareous soil (Calciaquoll) significantly improved correlations only for BP. Differences in relationships between runoff P and the soil tests were small or nonexistent among the noncalcareous soils. Routine soil P tests can estimate relationships between runoff P concentration and P application or soil P, although estimates would be improved by separate calibrations for calcareous and noncalcareous soils.

Midwestern United States↗
PubMed2001

Limitations of improved nitrogen management to reduce nitrate leaching and increase use efficiency.

The primary mode of nitrogen (N) loss from tile-drained row-cropped land is generally nitrate-nitrogen (NO3-N) leaching. Although cropping, tillage, and N management practices can be altered to reduce the amount of leaching, there are limits as to how much can be done. Data are given to illustrate the potential reductions for individual practices such as rate, method, and timing of N applications. However, most effects are multiplicative and not additive; thus it is probably not realistic to hope to get overall reductions greater than 25 to 30% with in-field practices alone. If this level of reduction is insufficient to meet water quality goals, additional off-site landscape modifications may be necessary.

Agriculture↗
PubMed2001

Intermittent hypoglycemia in a horse with anaplastic carcinoma of the kidney.

Clinically apparent hypoglycemia is rare in adult horses. Hypoglycemia is a well-recognized paraneoplastic syndrome in humans and dogs with non-insulin-secreting tumors and may occur in horses as well. Hypoglycemia associated with non-insulin-secreting tumors is believed to result from production of an abnormal form of insulin-like growth factor II. Neoplasia should be considered in the differential diagnosis for adult horses with hypoglycemia.

Abscess↗
PubMed2001

Epidemiology of abdominal aortic aneurysms in the Asian community.

BACKGROUND: Studies relating to the ethnic origin of patients with an abdominal aortic aneurysm (AAA) are few and are mainly concerned with the differences between black and white Americans. The purpose of this study was to determine whether the incidence of AAA among the Asian population of Bradford is different from that in the Caucasian population. METHODS: A retrospective study of patients with an AAA was carried out between 1990 and 1997 using data collected by the Patient Administrative Service, personal databases of the vascular consultants and theatre records. Information about the ethnic composition of the population of Bradford was obtained from the 1991 national census. Demographic data, including ethnic origin and clinical details, were obtained from patient notes. RESULTS: Two hundred and thirty-three patients with an AAA were identified during the study interval. The Asian population comprised 14.0 per cent of the total population of Bradford. Twenty-eight AAAs would be expected per year. All of the aneurysms identified occurred in the Caucasian population and none in the Asian community. CONCLUSION: These early results suggest that AAA is rare among the Asian population.

Age Distribution↗
PubMed2000

Use of expanded polytetrafluoroethylene in aesthetic surgery of the face.

Aesthetic surgery procedures and materials available to improve the appearance of various subunits of the face have been evolving for the past several decades. Initially, techniques such as direct excision or placement of autogenous tissue grafts (e.g., fat, fascia, tendon, and dermal fat grafts) were used. Additional options became available with the development of silicone, injectable collagen, and ePTFE. These options for facial augmentation can be done rapidly in an office setting and as an outpatient. An important aspect of treatment is discussing clearly all pertinent options with the patient, and recommending the appropriate option based on the patient's anatomic findings and personal needs. For example, patients desiring lip augmentation but unsure about the result may be best treated with collagen injection, which gives temporary results and lets the patient consider a long-term result provided by ePTFE or autogenous grafts. Use of ePTFE in facial aesthetic surgery gradually has increased over the past two decades. Its use in augmentation of lips, nasolabial creases, and nose is becoming an important treatment modality for aesthetic surgeons.

Biocompatible Materials↗
PubMed1999

Inhibition of aflatoxin biosynthesis by phenolic compounds.

The phenolic compounds acetosyringone, syringaldehyde and sinapinic acid inhibited the biosynthesis of aflatoxin B1 (AFB1) by A. flavus. Acetosyringone was the most active among the three compounds, inhibiting aflatoxin level by 82% at 2 m moll-1. The synthesis and accumulation of norsolorinic acid, an aflatoxin biosynthetic intermediate, was also inhibited. These results suggest that at least one step early in the AFB1 biosynthetic pathway is inhibited by the phenolics.

Acetophenones↗
PubMed1999

Interactions of saprophytic yeasts with a nor mutant of Aspergillus flavus.

The nor mutant of Aspergillus flavus has a defective norsolorinic acid reductase, and thus the aflatoxin biosynthetic pathway is blocked, resulting in the accumulation of norsolorinic acid, a bright red-orange pigment. We developed a visual agar plate assay to monitor yeast strains for their ability to inhibit aflatoxin production by visually scoring the accumulation of this pigment of the nor mutant. We identified yeast strains that reduced the red-orange pigment accumulation in the nor mutant. These yeasts also reduced aflatoxin accumulation by a toxigenic strain of A. flavus. These yeasts may be useful for reducing aflatoxin contamination of food commodities.

Aflatoxins↗
PubMed1999

A practical guide to ultrasound-assisted lipoplasty.

This article provides practical guidelines for plastic surgeons to incorporate ultrasound-assisted lipoplasty into their practice. Tips for improved results are provided and methods to avoid complications are discussed. The author also weighs the advantages and disadvantages of ultrasound-assisted lipoplasty and suction-assisted lipoplasty.

Anesthesia, General↗
PubMed1995

A model of intestinal ischemia in the neonatal rat utilizing superior mesenteric artery occlusion and intraluminal platelet-activating factor.

The human premature newborn is susceptible to necrotizing enterocolitis (NEC) in the first 1 to 3 weeks of life, a time when the gastrointestinal tract is structurally and functionally premature. Studies of NEC are hampered by the lack of a standard, reproducible model in newborn animals. The purpose of this study was to produce a model for intestinal ischemic injury in newborn rats. On Days 14, 18, 22, and 26 of life, newborn rats (10/day) were subjected to 1 hr of superior mesenteric artery occlusion with a microaneurysm clip. Platelet activating factor (PAF, 50 micrograms/kg) was injected into the lumen of the proximal small intestine after occlusion was initiated. Control animals (10/day) underwent sham laparotomy on Days 14, 18, 22, and 26. Animals were autopsied upon demise (7.6 +/- 0.7 hr) or at 24 hr. The intestine was inspected for gross ischemic changes and samples were taken for histology and myeloperoxidase (MPO, an index of neutrophil infiltration). Ischemic injury was graded in a blinded fashion, by a pathologist, using a scale from 0 to 4 (0, no injury; 4, full-thickness necrosis). All animals in the experimental groups had evidence of histologic injury (mean +/- SEM) on Days 14 (1.0 +/- 0.0), 18 (2.5 +/- 0.5), 22 (3.6 +/- 0.3), and 26 (3.1 +/- 0.5). The sham-operated control animals had no injury (P < 0.0001). MPO levels (U/g protein) on Days 18 (27.2 +/- 1.7 vs 13.9 +/- 2.3), 22 (40.9 +/- 5.4 vs 7.6 +/- 0.8), and 26 (29.3 +/- 4.4 vs 7.6 +/- 1.0) were significantly higher in experimental groups vs controls (P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Acute appendicitis: a cause of recurrent abdominal pain in pediatric trauma.

When traumatic abdominal injury and acute appendicitis occur within a short period of time, the diagnosis can be difficult and may result in a delay in treatment of the appendicitis. We report the case of a four-year-old boy with documented intraabdominal injury from a motor vehicle crash who developed appendicitis while hospitalized and recovering from his injuries.

Abdominal Injuries↗
PubMed1995

Persistent fatigue in well women.

Fatigue is the subjective report of a sustained sense of exhaustion with reduced motivation and capacity for physical and/or mental activity. Although factors associated with fatigue have been explored in specific patient populations, minimal study has been devoted to exploring both the magnitude of fatigue and associated variables among women generally thought to be well. This cross-sectional, descriptive study examined the relationship of behavioral, socio-demographic, and emotional factors to subjective ratings of fatigue among women in the community who perceived themselves as being fatigued but otherwise healthy. A convenience sample of 155 adult women completed the Piper Fatigue Self-Report Scale (PFS), the Beck Depression Inventory (BDI), and an investigator-designed questionnaire that collected behavioral and socio-demographic data. Correlation and regression analyses were used with fatigue as measured by the PFS as the outcome variable. Statistically significant relationships were noted between PFS and BDI scores as well as PFS and sleep pattern, rest quality, and perceived stress. Construction of a multiple regression model revealed an adjusted R2 of .43 with the BDI score serving as the major predictor variable for fatigue. Persistent fatigue is a consistent element in the lives of many women. As such it can significantly undermine women's quality of life.

Adult↗
PubMed1995

Classification of capsular contracture after prosthetic breast reconstruction.

The Baker classification of capsular contracture remains the most popular and practical method of assessing clinical firmness of the breast after augmentation mammaplasty. This classification system was never intended to describe prosthetic breast reconstruction. A modification of the Baker classification to include classes IA, IB, II, III, and IV has been developed to describe breast reconstruction more accurately. For this modified system, a soft but visible implant (class IB), an implant with mild firmness (class II), and an implant with moderate firmness (class III) could still be considered good or excellent outcomes. Only a class IV classification with an excessively firm and symptomatic breast resulting in a poor aesthetic result would necessarily be considered a poor outcome.

Adult↗
PubMed1994

The health status of women following cosmetic surgery.

A retrospective study was performed to determine the frequency of new symptoms and diseases after silicone breast implantation. Questionnaires were mailed to 826 women who made up a breast implant group (n = 516) and a control group who had undergone blepharoplasty (n = 124), liposuction (n = 111), or rhinoplasty (n = 75). Responses were obtained from 370 women (45 percent); however, 68 of these patients (18 percent) were considered ineligible. The overall response rate was 59 percent for the breast implant group and 46 percent for controls. The 302 eligible women included patients with silicone breast implants (n = 222) and controls (n = 80). Women with implants were significantly younger than controls, the median age of women with breast implants being 37 years compared with 46.5 years for controls (p < 0.0001). We compared the incidence of 23 symptoms and 4 connective-tissue diseases after cosmetic surgery in the two groups. The symptoms of swollen glands under arms (p < 0.05) and tender glands under arms (p < 0.01) were statistically more frequent in the breast implant group. The symptom change in skin color was more common in the controls (p < 0.001). The Bonferroni correction for multiple (27) endpoints adjusts the 5 and 1 percent significance cutoff points to 0.00185 and 0.00037, respectively, leaving only change of skin color significant at the 5 percent level on the adjusted data. No cases of scleroderma or lupus were found, and the incidence of arthritis was not significantly different between the implant and control groups.

Adult↗
PubMed1993

Inflammatory enzyme composition of the neonatal rat intestine: implications for susceptibility to ischemia.

Recent evidence has suggested that the immaturity of the neonatal intestine may play a key role in the development of ischemic injury. However, relatively little data exist on the susceptibility of the neonatal intestine to ischemic injury at various ages especially in the fed versus fasted states. In this study, the levels of xanthine oxidase ([XO] an enzyme which is a known, major source of free radicals in postischemic tissue) and myeloperoxidase ([MPO] an index of tissue neutrophil infiltration) were measured in 1-, 5-, 10-, 15-, and 20-day-old Sprague-Dawley rats. Rats were divided into fed (n = 8/day) and fasted (n = 8/day) groups 4 hours prior to sacrifice. The entire small intestine was removed and divided into five segments: the duodenum, proximal jejunum, distal jejunum, proximal ileum, and distal ileum. The specimens were homogenized and assayed for XO and MPO levels. A significant increase in XO was observed in the fasted animals compared to the fed animals on all days. Peak levels in XO were observed in both groups from day 5 to 10. MPO levels were significantly higher in the fasted versus fed animals on day 1. MPO levels decreased as the animals aged. These data demonstrate dramatic differences in the levels of inflammatory enzymes of the newborn rat in the fed versus fasted states. Also, marked variations with age are seen in both XO and MPO. Whether the XO and MPO levels present at the time of ischemic insult affect severity of injury remains to be seen.

Animals↗
PubMed1992

Two classes of spontaneous GABA-mediated miniature synaptic currents in cultured rat hippocampal neurons.

Amplitude and time course of spontaneous gamma-aminobutyric acid (GABA)-mediated miniature postsynaptic currents (MPSCs), recorded in cultured embryonic hippocampal neurons in presence of either tetrodotoxin (TTX) or increased external [Mg2+/Ca2+] ratio, revealed that they form two classes. The distribution of the most commonly recorded MPSCs was skewed both in terms of peak amplitude and rise-time (skew-MPSCs, mode: 70-120 pS). Another, less frequent class (mode: 1-3 nS) formed bell-shaped (bell-MPSCs) amplitude and rise-time distributions. MPSC initial slope did not correlate with rise time, indicating that smaller MPSCs were not electrotonically attenuated. Bell-MPSCs did not result from the integration of skew-MPSCs and both classes appeared to be composed of subunits.

Animals↗
PubMed1992

Influence of breast versus formula milk on physiological gastroesophageal reflux in healthy, newborn infants.

The effect of milk type on physiological, gastroesophageal reflux (GER) was studied in 37 breast-fed and 37 formula-fed, healthy, term neonates aged 2-8 days. The neonates were randomly selected from the public maternity ward and studied for 4 h after their morning milk feed. GER was recorded by a pH microelectrode placed 6 cm above the gastroesophageal junction and analyzed in the third and fourth postprandial hours. Sleep state was accurately defined from the electroencephalogram, electrooculogram, electromyogram, breathing, and behavioral observations. Movement was recorded from a piezo-electric transducer. In active sleep, the breast-fed neonates demonstrated GER episodes of significantly shorter duration than the formula-fed neonates. The means and 95% confidence intervals (CI) were 3.0 (1.6,5.2) compared with 8.3 (5.0,13.3) min/h of active sleep respectively (p less than 0.05). This could not be explained by greater milk volume or increased movement before or during reflux in formula-fed neonates. However, the lower median pH values for GER in breast-fed neonates, 2.0 versus 2.5, were significantly different (p less than 0.05). This difference may reflect more rapid gastric emptying. The lower esophageal pH is more likely to stimulate peristalsis and thus limit the duration of reflux (shorter episodes), in the breast-fed neonates.

Animals↗
PubMed1991

Retinal capillary hemangioma.

Capillary hemangiomas of the retina, which commonly occur as part of von Hippel's disease, are classically composed of a retinal capillary tumor, a large feeder arteriole, and a draining venule. The fundamental pathology is a hamartomatous lesion. In this paper, the case of an early, incipient lesion will be presented. Since approximately 25 percent of patients with angiomatosis retinae develop the life-threatening von Hippel-Lindau disease, the eye care practitioner needs to be aware of this condition. Also included in the discussion are the treatment options available for these retinal abnormalities.

Adolescent↗