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Biomedical subjects

J L Baker

Publications and source records attributed to J L Baker.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1987

Electrocardiographic changes during antihypertensive therapy in the International Prospective Primary Prevention Study in Hypertension.

In the International Prospective Primary Prevention Study in Hypertension, electrocardiographic changes before and during 3- to 5-year antihypertensive treatment were investigated in a cohort of 5819 men and women aged 40 to 64 years with entry diastolic blood pressures of 100 to 125 mm Hg. They were randomly allocated to treatment regimens that either included or excluded the slow-release beta-blocker oxprenolol. Electrocardiograms (ECGs) were assessed using the Minnesota Code and assigned to groups of normal ECGs or ECGs with pressure-related, ischemic, "intermediate," or "other" abnormalities. Antihypertensive treatment was associated with a decrease (mainly in men) of pressure-related and (mainly in women) of intermediate abnormalities. Ischemic abnormalities increased, particularly in men. Inclusion of the beta-blocker resulted in a greater reduction in intermediate abnormalities and in a lesser increase in ischemic abnormalities. Better blood pressure control was associated with a lesser increase in ischemic abnormalities and in a regression of pressure-related abnormalities. The presence of ST segment depression and of a complete left bundle branch block in the entry ECG was associated with a significant risk for sudden death and myocardial infarction. Optimal blood pressure control prevents pressure-induced cardiac target organ damage and, hence, heart failure, and may delay the progression of ischemic abnormalities. This tallies with the lower critical cardiac event rate associated with lower blood pressure that was observed in the same study.

Antihypertensive Agents↗
PubMed1987

Comparative efficacy and safety of mezlocillin, cefoxitin, and clindamycin plus gentamicin in postpartum endometritis.

The efficacy of mezlocillin versus cefoxitin versus clindamycin plus gentamicin was evaluated in 152 patients with postpartum endometritis. There were no statistically significant differences in rate of cure among the three groups (87% with mezlocillin, 82% with cefoxitin, and 92% with clindamycin-gentamicin). There were no severe adverse reactions observed in any of the three treatment regimens. Mezlocillin is as safe and effective as cefoxitin and clindamycin-gentamicin for treatment of postpartum endometritis.

Bacteriuria↗
PubMed1983

Male rhytidectomy incisions.

Because the preauricular segment of a face lift incision is less noticeable when located behind the tragus, it is our preferred method in females. The desirability of preserving the normal hairless strip between the ear and sideburn precluded using the technique in males. In this report we describe a method of utilizing the retrotragal location in males. This has been accomplished by direct excision of the hair follicles and hair shafts.

Dermatologic Surgical Procedures↗
PubMed1983

Restricted energy intake and elevated calcium and phosphorus intake for gilts during growth. IV. Characterization of metacarpal, metatarsal, femur, humerus and turbinate bones of sows during three parities.

The effect of early nutrition on subsequent bone development was studied using gilts that had previously been fed ad libitum or 75% ad libitum intake and 100 or 150% National Research Council-recommended daily Ca and P from weaning to 100 kg. During the three-parity reproductive study, sows were fed a 14% protein diet. Metacarpals and metatarsals were taken from sows culled due to lameness or failure to breed and from sows after completing three parities. Femur and humerus articular cartilage and turbinates were described at necropsy. Metacarpals and metatarsals were heavier and tended to have thicker walls when sows were previously fed ad libitum or fed 150% Ca and P. Energy intake produced the greater response. Metacarpal breaking strength was greatest for sows previously fed ad libitum. Metatarsals were not affected by energy intake. Stiffness, Young's modulus of elasticity (YME) and flexural modulus for metacarpals and metatarsals were not affected by energy intake. Previously fed Ca and P intakes did not affect any of the mechanical bone characteristics. Metacarpals were heavier, had a greater breaking strength, were more elastic and exhibited slightly less resistance to bending than the metatarsals. The ether extract, ash, Ca and P content and the Ca:P ratio of metacarpals and metatarsals were not affected by previously fed energy or Ca and P intakes. The ether extract content tended to decrease and the ash, Ca and P content tended to increase with age. Articular cartilage and turbinate scores were not influenced by previously fed energy or Ca and P intakes. The YME and flexural modulus were the only bone characteristics that were even poorly correlated (average r = .25) with soundness scores, suggesting that high values result in poorer soundness scores. Energy and Ca and P intakes during growth and development had only minimal effects on bone characteristics and no apparent effect on structural soundness and longevity of sows kept for three parities.

Animals↗
PubMed1982

Positive identification of silicone in human mammary capsular tissue.

A specific quantitative assay was developed to determine silicone concentrations in contracted mammary capsular tissue. The concentrations of silicone in tissues from 14 patients with gel-filled implants varied from 15 to 9800 micrograms polydimethylsiloxane per gram of tissue. This silicone is probably a high-molecular-weight polymer that has diffused through the implant envelope. Samples from a patient with saline-filled implants contained no silicone. The concentration of silicone was not related to capsule age. The polymer in these tissues appeared to be unaltered, in that no evidence of metabolic products was found.

Breast↗
PubMed1981

The effectiveness of alpha-tocopherol (vitamin E) in reducing the incidence of spherical contracture around breast implants.

Vitamin E appears to be a safe, simple, and inexpensive means of reducing the number of postoperative capsular contractures following breast augmentation. The synthetic form of vitamin E (alpha-tocopherol) is recommended to avoid nausea or skin eruptions in patients with oily skin, which are frequently encountered when the natural form is taken. No harmful side effects have been noted in any of the patients to date. Vitamin E has no effect on coagulation systems and does not cause excessive bleeding either during or after surgery. The recommended dosage of synthetic vitamin E is 1000 IU, b.i.d., for 2 years beginning 1 week before surgery. If no contracture exists at that time, the dosage may be reduced to 1000 IU daily thereafter.

Breast↗