PubMed Health⌕ Search

Biomedical subjects

J L Baker

Publications and source records attributed to J L Baker.

At least 19 recordsLinked to original sources
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↗
PubMed1990

Agricultural chemical management practices to reduce losses due to drainage.

Chemical losses with water and sediment are a product of the mass of carrier and chemical concentration in that carrier. One approach to controlling losses is to utilize chemical management practices that reduce the chemical concentrations in the water and sediment that leave a treated field; another is to control the masses of the carriers. In this paper, emphasis will be placed on the former, with a discussion of rate, timing, placement, and choice-of-chemical options available for the application of fertilizers and pesticides and their effect on offsite losses with surface and subsurface drainage. Particular emphasis will be on the known effects of application variables on nitrate-nitrogen (NO3-N) leaching and on herbicide losses in both surface runoff water and sediment and with percolation water. Current understanding of chemical transport processes will be used to extrapolate to situations in which actual data are not available. Areas of research to fill these data gaps and to improve our understanding of the effects of current management practices on losses and also to develop new chemical management practices to increase further the efficiency of use and reduce losses will be addressed. The usefulness of standards, or some form of health advisory levels, as goals for levels of control necessary will also be noted.

Agriculture↗
PubMed1990

Prevalence of human immunodeficiency virus seropositivity in pediatric emergency room patients undergoing phlebotomy.

Information on the prevalence of human immunodeficiency virus (HIV) infection among children and adolescents requiring medical care is sparse. A small but significant risk of seroconversion occurs in health care workers who handle blood and body fluids of patients infected with HIV. The prevalence of HIV seropositivity in children who had phlebotomy as part of emergency care was measured. Of 749 blood samples, 21 (2.8%) tested positive for HIV antibody by enzyme-linked immunosorbent assay and Western Blot analysis: 14 samples from 6 patients with hemophilia, 6 from 3 patients with acquired immunodeficiency syndrome/acquired immunodeficiency syndrome-related complex, and 1 from a patient with asthma. Of these 21 blood samples, 10 were from 4 children previously known to be HIV positive, 4 were from patients with a known parental risk factor, and 16 were from patients with known history of blood transfusion. One sample was from a children with unknown HIV status and no documented risk factors. Procedures included 9 venipunctures, 17 intravenous line placements, 1 lumbar puncture, and 1 pelvic examination. Most patients with HIV seropositivity had been known to be HIV seropositive or at significant risk for HIV seropositivity. Although the potential risk to health care workers from children without known risk factors for HIV seropositivity was small in this population, the currently recommended infection-control precautions should always be observed.

Adolescent↗
PubMed1989

Substantial increase in human immunodeficiency virus (HIV-1) infection in critically ill emergency patients: 1986 and 1987 compared.

In a follow-up study conducted one year after a previous report, we found that 7.8% of 126 patients with critical illness or injury were infected with the human immunodeficiency virus (HIV-1) in 1987 as compared with 3.0% of 203 similar patients in 1986. In the earlier study all patients with infection (six) were confined to a narrow age range (25 to 34 years old) and were trauma presentations. However, in the follow-up study, infections were found in all age groups under 45 years of age (nine) as well as in 3.4% of patients with nontrauma presentations. Infection rates among patients between the ages of 25 and 34 presenting with penetrating trauma remained over 18% during both study periods. While emergency health care providers may have inadvertently interpreted the results of the first study as indicating that the need for infection control precautions could be restricted to young victims of trauma, the follow-up study clearly indicates that appropriate protective measures must be taken on all patients requiring resuscitative measures regardless of age or clinical presentation, particularly in emergency facilities within similar locations.

AIDS Serodiagnosis↗
PubMed1988

Unrecognized human immunodeficiency virus infection in emergency department patients.

To determine the extent of unrecognized human immunodeficiency virus (HIV) infection, we examined blood samples drawn from patients presenting to an inner-city emergency department. We found 119 of 2302 consecutive adult patients (5.2 percent) to be seropositive for HIV. Although 27 patients presented with known symptomatic HIV infection, 92 of the remaining 2275 patients (4.0 percent) had unrecognized HIV infection. The highest seroprevalence rate (11.4 percent) was found among black men 30 to 34 years of age. Blacks, other nonwhites, and patients under the age of 45 had high rates of unrecognized infection. The clinical team established risk-factor status in only 29.0 percent of the patients. Of the 276 patients with identified risk factors, 13.0 percent were seropositive, whereas 3.1 percent of the 1616 patients with unknown risk-factor status were seropositive. None of the 102 patients who reported no risk factors were seropositive. Although penetrating trauma (seroprevalence, 13.6 percent) was the only clinical presentation associated with an increased seroprevalence rate independent of other known predictors of infection (P = 0.02), seropositive patients were found in all categories of clinical condition. These data, although based on observations in one emergency department setting, support the concept of universal blood and body-fluid precautions by all health care workers whether or not HIV infection is known.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Selenium-mediated reduction in the mutagenicity of cigarette smoke.

Cigarette smoke contains carcinogens and mutagens and affects the health of smokers. Recently, increased research has proven the potentially protective activity of selenium (Se) against heavy metal toxicity, cancer, and other health disorders. Accordingly, we have proposed the fortification of tobacco with Se to develop safer cigarettes. As a start in evaluating any biological effects of added Se, we have determined the mutagenicity of inhaled, mainstream (MS) cigarette smoke condensate (CSC), with and without Se, in the preincubation assay of the Ames test. Initially, it was shown that Se, as sodium selenite, was not mutagenic at high concentrations (up to 80 micrograms/plate) with strains TA1538 and TA1978. Subsequently, the effects of different levels of Se, added to MS CSC, were examined with TA98, TA100, and TA1538. On the average, addition of 10 micrograms Se produced mutagenicity reductions of about 50%. Higher levels of added Se yielded further reductions. Cigarette sidestream (SS) smoke, collected between puffs, was also tested. Again, Se added to SS-CSC gave similar reductions, confirming its antimutagenic effect for both mainstream and sidestream smoke.

Animals↗
PubMed1988

What is the occupational risk to emergency care providers from the human immunodeficiency virus?

The risk to health care providers of acquiring human immunodeficiency virus (HIV) infection through occupational exposure is very low, but the consequences of becoming infected are obviously severe. The magnitude of this risk has been debated extensively in the medical literature, but the majority of these discussions have focused on providers of surgical, orthopedic, and obstetric care, none of whom have ever been documented to have become infected with HIV through occupational exposure. In contrast, there has been very little information published regarding the degree of risk to emergency care providers, several of whom have been confirmed as having acquired HIV infection through occupational exposures. This report addresses the extent and nature of risk of HIV infection to emergency care providers and reviews the current management of significant exposures.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Hepatozoon canis in a dog with oral pyogranulomas and neurologic disease.

A ten-month-old Cocker Spaniel presented for fever, difficulty walking, and oral lesions. Muscle pain, bloody diarrhea, respiratory disease and central nervous system inflammation were found while the animal was hospitalized. Merozoites of Hepatozoon canis were discovered in association with pyogranulomas in a muscle biopsy. No other etiologic agent for the clinical signs was identified.

Animals↗
PubMed1987

Unsuspected human immunodeficiency virus in critically ill emergency patients.

To determine the prevalence of unsuspected human immunodeficiency virus (HIV) infection in critically ill emergency patients, we examined the anonymous serum samples of 203 critically ill or severely injured patients with no history of HIV infection. We found that six (3%) were seropositive for HIV antibody by both enzyme-linked immunoassay and Western blot analysis. All seropositives were trauma victims between the ages of 25 and 34 years, representing 16% of the trauma patients in that age group (n = 37). All seropositives were actively bleeding, and all required multiple invasive procedures. History of intravenous drug abuse was not discriminating in identifying potential seropositives. We conclude that infection-control precautions are indicated for both emergency department personnel and prehospital care providers (such as paramedics, police officers, and fire fighters) when caring for bleeding patients, whether or not previous suspicion of HIV infection exists.

Acquired Immunodeficiency Syndrome↗